TY - JOUR
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Bala, P.
T1 - Refined Calibration Model for Improving the Orientation Precision of Electron Backscatter Diffraction Maps
N2 - For the precise determination of orientations in polycrystalline materials, electron backscatter diffraction (EBSD) requires a consistent calibration of the diffraction geometry in the scanning electron microscope (SEM). In the present paper, the variation of the projection center for the Kikuchi diffraction patterns which are measured by EBSD is calibrated using a projective transformation model for the SEM beam scan positions on the sample. Based on a full pattern matching approach between simulated and experimental Kikuchi patterns, individual projection center estimates are determined on a subgrid of the EBSD map, from which least-square fits to affine and projective transformations can be obtained. Reference measurements on single-crystalline silicon are used to quantify the orientation errors which result from different calibration models for the variation of the projection center.
KW - Scanning electron microscopy
KW - Electron backscatter diffraction
KW - Kikuchi diffraction
KW - Projection center
KW - Orientation precision
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509342
DO - https://doi.org/10.3390/ma13122816
VL - 13
IS - 12
SP - 2816
PB - MDPI
AN - OPUS4-50934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Schilling, Markus
T1 - Environmental Stress Cracking (ESC) and Slow Crack Growth (SCG) of PE-HD induced by external fluids
N2 - High-density polyethylene (PE-HD) is widely used as a packaging material. Typical applications are pipes and containers for storage and transport of dangerous goods. For these applications, the understanding of the craze-crack damage mechanisms slow crack growth (SCG) and environmental stress cracking (ESC) is of importance. Since these mechanisms are considered to be the major causes of failure, their understanding is essential for inspection and release of those materials.
A well-established test method for the assessment of these damage mechanisms is the full-notch creep test (FNCT). It is used in this study for a detailed investigation of crack propagation phenomena in PE-HD container materials under the influence of different fluids such as air, water and aqueous detergent solutions (Arkopal N 100) as well as biodiesel and diesel. Based on the results of the FNCT, a classification scheme of different fluids is proposed, which allows for an assignment of the respective damage mechanisms. Hereby, it is differentiated between (i) inert, (ii) purely surface-active and (iii) additionally sorptive, bulk-active fluids with respect to SCG. If the test fluid changes the intrinsic properties (at the surface or in the bulk), the damage mechanism is addressed to ESC behavior.
In FNCT investigations, stress, temperature and specimen geometry were varied systematically. In addition to the time to failure as common measure for the resistance of a PE-HD type against crack propagation, specimen elongation was considered in detail.
Several imaging techniques were applied for fracture surface analysis of specimens tested in FNCT to gain novel information on SCG and ESC behavior. From height profiles obtained by laser scanning microscopy (LSM) and information on surface structures from scanning electron microscopy (SEM), indicators for the differentiation of the crack propagation mechanisms could be derived. Based on the LSM data, an algorithm for the distinction between ductile shear deformation and brittle crack growth as dominating failure mechanism was developed. Imaging techniques were also used for determination of crack propagation rates, which were related to time-resolved FNCT elongation data. From the time-resolved determination of crack lengths of partly damaged FNCT specimens, an increasing length of craze zone with a progressively propagating crack was revealed for the first time. This relation of crack and craze zones was specified by fracture mechanical considerations.
N2 - Polyethylen hoher Dichte (PE-HD) wird als Werkstoff für Rohre und Behälter für den Transport und zur Lagerung von Gefahrgütern verwendet. Für die Beurteilung und technische Freigabe dieser Materialien ist das Verständnis der beiden Schädigungsmechanismen „langsames Risswachstum“ (engl.: „slow crack growth“, SCG) und „umgebungsbedingter Spannungsriss“ (engl.: „environmental stress cracking“, ESC) essentiell.
Eine etablierte Prüfmethode zur Bewertung dieser Schädigungsmechanismen ist der Full-Notch Creep Test (FNCT), der in dieser Arbeit zur systematischen Untersuchung des Risswachstums in PE-HD Behältermaterialien unter Einwirkung von Luft, Wasser und wässrigen Netzmittellösungen (Arkopal N 100) sowie Biodiesel und Diesel verwendet wird. Aus den Ergebnissen des FNCT wird ein Klassifikationsschema für Fluide vorgeschlagen, welches ebenfalls eine Zuordnung zu den Schädigungsmechanismen erlaubt. Hierbei wird in (i) inerte, (ii) rein oberflächen-aktive und (iii) zusätzliche sorptive, volumen-aktive Fluide hinsichtlich des langsamen Risswachstums (SCG) unterschieden. Wenn ein Fluid lokal die intrinsischen Materialeigenschaften des Polymers verändert, wird der Schädigungsmechanismus dem umgebungsbedingten Spannungsriss (ESC) zugeordnet.
Bei den FNCT-Untersuchungen wurden die mechanische Spannung, die Temperatur und die Prüfkörpergeometrie systematisch variiert. Zusätzlich zur Standzeit wurde die Prüfkörperdehnung zeitabhängig erfasst.
Aus einer erweiterten Bruchflächenanalyse konnten neuartige Informationen über SCG und ESC erhalten werden. Hierzu wurden verschiedene Bildgebungsverfahren verwendet. Insbesondere wurden mit Laserscanningmikroskopie (LSM) Höhenprofile und mit Rasterelektronenmikroskopie (REM) Oberflächeninformationen zur Charakterisierung der Rissfortschrittsmechanismen erhalten. Auf Basis der LSM wurde unter Zuhilfenahme von Höhenprofildaten ein Algorithmus zur Unterscheidung zwischen duktiler Scherverformung und sprödem Risswachstum als dominierende Schädigungsmechanismen entwickelt. Die aus den bildgebenden Verfahren ermittelten Rissfortschrittsraten konnten mit den Daten der während des FNCT erfassten Dehnung der Prüfkörper in Beziehung gesetzt werden. Weiterhin wurde mithilfe von zeitaufgelösten Risslängendaten erstmals eine direkte Korrelation der Risslänge zu vorgeschädigten, fibrillierten Bereichen (Crazes) im PE-HD Prüfkörper während des FNCT nachgewiesen. Demnach vergrößert sich die Craze-Länge linear mit zunehmender Risslänge. Dieser Zusammenhang zwischen Riss- und Craze-Längen wurde auf mathematisch, bruchmechanischer Grundlage bestätigt.
KW - High-density polyethylene (PE-HD)
KW - Full-Notch Creep Test (FNCT)
KW - Slow crack growth (SCG)
KW - Environmental Stress Cracking (ESC)
KW - Biodiesel
KW - Diesel
KW - Crack propagation analysis
KW - Fracture Surface Analysis
KW - Test Improvement
KW - Imaging
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:tuda-tuprints-115443
DO - https://doi.org/10.25534/tuprints-00011544
SP - 1
EP - 212
CY - Darmstadt
AN - OPUS4-50941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rolle, Annette
A1 - Komann, Steffen
A1 - Wille, Frank
ED - Baraldi, P.
ED - Di Maio, F.
ED - Zio, E.
T1 - Ageing aspect in the safety evaluation of special form radioactive material
N2 - In accordance with the IAEA transport regulations Special Form Radioactive Material (SFRM) is either an indispersible solid radioactive material or a sealed capsule containing radioactive material.
The design of special form radioactive material has to resist a severe transport accident without undue loss or dispersal of radioactive material. The safety assessment for design approval shall include besides the required test program (impact, percussion, bending and heat test) also the evaluation of the management system for design, manufacture, testing, documentation, use, maintenance and inspection. The specified quality assurance measures have to assure, that every specimen of the approved design is produced in the same verified quality and every specimen must be able to survive the severe mechanical and thermal tests at any time of its working life.
Due to the long-term use of SFRM the consideration of ageing is an important aspect in the approval procedure by BAM, the competent authority for SFRM approval in Germany. Different fields of application imply a wide range of environmental conditions, from clean room atmosphere to highly aggressive industrial conditions. So, besides of radioactive content, corrosion is a main factor for possible design degradation.
This paper will describe major influencing factors to be taken into account to assess the ageing behavior of a SFRM design and will emphasize that there is a need for a regulatory specification of a SFRM-working life as basis for the aging evaluations.
T2 - 30th European Safety and Reliability Conference and 15th Probabilistic Safety Assessment and Management Conference (ESREL2020 PSAM15)
CY - Online meeting
DA - 01.11.2020
KW - Special form radioactive material
KW - Transport
KW - Ageing
KW - Material
KW - Safety assessment
KW - Management system
PY - 2020
UR - https://www.rpsonline.com.sg/proceedings/esrel2020/html/3659.xml
SN - 987-981-14-8593-0
SP - Paper 3659,1
EP - 5
PB - Research Publishing
CY - Singapore
AN - OPUS4-50969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Ghigo, Tea
A1 - Torallas, S.
T1 - Between Literary and Documentary Practices: The Montserrat Codex Miscellaneus (Inv. Nos. 126‐178, 292, 338) and the Material Investigation of Its Inks
N2 - The Montserrat Codex Miscellaneus (TM 59453/LDAB 552) has been the subject of numerous studies since the publication of ist first text by its owner, father Ramon Roca-Puig. Scholars have dealt with the content of its texts, as well as interrogated its origin and materiality. It is a fourth-century papyrus single quire codex, which contains texts in both Latin and Greek. It has been argued that it belonged to the Bodmer library, connected to a Pachomian library in the Thebaid. In this paper we want to contribute to the material study of the codex by presenting the first results of an archaeometric analysis performed upon the inks. The Analysis was carried out within the framework of the ‘PAThs’ project based at Sapienza University of Rome, and executed with the close cooperation of DVCTVS, a team of scholars who curate the Roca-Puig collection. The results obtained have not only cast light on the history of production of the codex, but also, and perhaps most importantly, point out that a meaningful interpretation of the analytical data is only possible through an interdisciplinary collaboration between the humanities and the natural sciences.
KW - Interdisciplinary approach
KW - Codex Miscellaneus
KW - Palaeography
KW - Book production
KW - Archaeometry
KW - Ink analysis
PY - 2020
SP - 101
EP - 114
AN - OPUS4-51004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vollert, F.
A1 - Thomas, Maximilian
A1 - Kromm, Arne
A1 - Gibmeier, J.
T1 - Solidification Cracking Assessment of LTT Filler Materials by Means of Varestraint Testing and μCT
N2 - Investigations of the weldability of metals often deal with hot cracking, as one of the most dreaded imperfections during weld fabrication. The hot cracking investigations presented in this paper were carried out as part of a study on the development of low transformation temperature (LTT) weld filler materials. These alloys allow to mitigate tensile residual stresses that usually arise during welding using conventional weld filler materials. By this means, higher fatigue strength and higher lifetimes of the weld can be achieved. However, LTT weld filler materials are for example, high-alloyed Cr/Ni steels that are susceptible to the formation of hot cracks. To assess hot cracking, we applied the standardized modified varestraint transvarestraint hot cracking test (MVT), which is well appropriate to evaluate different base or filler materials with regard to their hot cracking susceptibility. In order to consider the complete material volume for the assessment of hot cracking, we additionally applied microfocus X-ray computer tomography (μCT). It is shown that by a suitable selection of welding and MVT parameter the analysis of the complete 3D hot crack network can provide additional information with regard to the hot cracking model following Prokhorov. It is now possible to determine easy accessible substitute values (e.g., maximum crack depth) for the extent of the Brittleness Temperature Range (BTR) and the minimum critical strain Pmin.
KW - LTT weld filler materials
KW - μCT-analysis
KW - Hot cracking
KW - Varestraint test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509126
DO - https://doi.org/10.3390/ma13122726
VL - 13
IS - 12
SP - 2726
PB - MDPI
AN - OPUS4-50912
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahrbach, M.
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
A1 - Peiner, Erwin
T1 - Calibrating a high-speed contact-resonance profilometer
N2 - A European EMPIR project, which aims to use large-scale piezoresistive microprobes for contact resonance applications, a well-established measurement mode of atomic force microscopes (AFMs), is being funded. As the probes used in this project are much larger in size than typical AFM probes some of the simplifications and assumptions made for AFM probes are not applicable. This study presents a guide on how to systematically create a model that replicates the dynamic behavior of microprobes, including air damping, nonlinear sensitivities, and frequency dependencies. The model is then verified by analyzing a series of measurements.
KW - Piezoresistive cantilever
KW - AFM
KW - contact resonance
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509899
DO - https://doi.org/10.5194/jsss-9-179-2020
VL - 9
SP - 179
EP - 187
PB - Copernicus Publications
AN - OPUS4-50989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhattacharya, Biswajit
A1 - Das, S.
A1 - Lal, G.
A1 - Soni, S. R.
A1 - Ghosh, A.
A1 - Reddy, C. M.
A1 - Ghosh, S.
T1 - Screening, crystal structures and solubility studies of a series of multidrug salt hydrates and cocrystals of fenamic acids with trimethoprim and sulfamethazine
N2 - Multidrug solids have a potential use to efficiently treat and control a superfluity of medical conditions.
To address the current drawbacks of drug development in R&D, it was targeted to achieve new pharmaceutical solid forms of fenamic acids having improved solubility and thermal stability. Subsequently, five new multicomponent solids consisting of three salt hydrates of trimethoprim (TMP) with mefenamic acid (TMP-MFA-H2O), tolfenamic acid (TMP-TFA-H2O) and flufenamic acid (TMP-FFA-H2O), and two cocrystals of sulfamethazine (SFZ) with flufenamic acid (SFZ-FFA) and niflumic acid (SFZ-NFA) were prepared by liquid assisted grinding. Looking at the structures of active pharmaceutical ingredient (API) molecules, it was quite expected that a wide range of supramolecular synthons would lead to cocrystallization.
New forms were characterized thoroughly by various solid-state techniques, including single crystal X-ray diffraction (SCXRD), which provided details of hydrogen bonding, molecular packing and interactions between drug and coformer. Kinetic solubility at pH 7.4 buffer study has been carried out and a comparison is made with respect to the parent drugs. A significant enhancement of NSAIDs solubility was observed in all salt hydrate systems of TMP. Thus with increasing physicochemical properties such as improved solubility further leads to the enhancement of bioavailability, which has implications to overcoming the formulation related problems of active pharmaceutical ingredients (APIs).
KW - Cocrystals
KW - Crystal engineering
KW - Solubility
PY - 2020
DO - https://doi.org/10.1016/j.molstruc.2019.127028
SN - 0022-2860
VL - 1199
SP - 127028
PB - Elsevier B.V.
AN - OPUS4-49873
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ehlers, Henrik
A1 - Pelkner, Matthias
A1 - Thewes, R.
T1 - Heterodyne Eddy Current Testing Using Magnetoresistive Sensors for Additive Manufacturing Purposes
N2 - In recent years additive manufacturing technologies have become widely popular. For complex functional components or low volume production of workpieces, laser powder bed fusion can be used. High safety requirements, e.g. in the aerospace sector, demand extensive quality control. Therefore, offline non-destructive testing methods like computed tomography are used after manufacturing. Recently, for enhanced profitability and practicality online non-destructive testing methods, like optical tomography have been developed. This paper discusses the applicability of eddy current testing with magnetoresistive sensors for laser powder bed fusion parts. For this purpose, high spatial resolution giant magnetoresistance arrays are utilized for testing in combination with a single wire excitation coil. A heterodyne principle minimizes metrology efforts. This principle is compared to conventional signal processing in an eddy current testing setup using an aluminum test sample with artificial surface defects. To evaluate the influence of the powder used in the manufacturing process on eddy current testing and vice versa, a laser powder bed fusion mock-up made from stainless steel powder (316L) is used with artificial surface defects down to 100 µm. This laser powder bed fusion specimen was then examined using eddy current testing and the underlying principles.
KW - Eddy current testing
KW - Heterodyning
KW - Laser powder bed fusion
KW - Giant magnetoresistance
KW - Additive manufacturing
KW - 316L
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506140
DO - https://doi.org/10.1109/JSEN.2020.2973547
SN - 1530-437X
VL - 20
IS - 11
SP - 5793
EP - 5800
PB - IEEE
AN - OPUS4-50614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Zentrifugentechnologie zur statistischen Untersuchung von Stumpfklebungen: Ergebnisse ZENSUS-Ringversuchs
N2 - Der Vortrag widmet sich der „Zentrifugentechnologie zur statistischen Untersuchung von Stumpfklebungen“ und beschreibt drei wesentlich verschiedene Realsysteme (Fügefläche 1/Klebstoff/ Fügefläche 2), um die Statistik ZPM (wiederholte Ein-Proben-Prüfung) vs. CAT (Mehr-Proben-Prüfung) zu vergleichen. Dazu wurden drei unterschiedliche Klebstoff-klassen mit typischen Fügeteilmaterialkombinationen ausgewählt und in einem Vorversuch mit jeweils 3 unterschiedlichen Prüfgeschwindigkeiten sowohl im Weg-geregelten als auch Kraft-geregelten Mode beansprucht. Die Ergebnisse ZPM vs. CAT und Kraft- vs. Weg-Regelung des Vorversuches zeigten keinerlei Unterschiede auf. Im Ergebnis wurde ein Ringversuch im Kraft-geregelten Mode (6xZPM vs. 8xCAT) für ein Referenzsystem durchgeführt, der nachwies, dass die CAT-Technologie statistisch relevante Prüfergebnisse zur Klebfestigkeit bereitstellt. Es zeigte sich, dass für zwei ZPM-Teilnehmer im Vertrauensbereich 99% statistisch signifikant etwas kleinere Werte der Klebfestigkeit bestimmt wurden, was auf geringfügige Abweichungen von der axialen Ausrichtung des eingespannten Prüflings bei der Ein-Proben-ZPM-Zugprüfung zurückgeführt wird.
T2 - VCI
CY - Frankfurt/Main, Germany
DA - 10.03.2020
KW - Zentrifugentechnologie
KW - Statistischen Untersuchung
KW - Normung
KW - Prüfgeschwindigkeiten
KW - Stumpfklebungen
PY - 2020
AN - OPUS4-50581
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Influence of relative humidity on wear of self-mated 100 Cr6 steel
N2 - The influence of relative humidity on friction and wear is subject of several studies in the last decades. A comprehensive understanding of physical and chemical phenomena affecting the tribology is hampered by the lack of reproducible experimental results, by the large number of variables, and by several difficulties in the detection of tribochemical processes and products.
In the present work, we analyze the wear coefficient and the wear volumes of 686 unlubricated tests performed on different oscillating tribometers with 100Cr6 balls on 100Cr6 planes at different relative humidity.
Aim of this work is to assess the repeatability and reproducibility of data, to determine the dependence of the wear coefficient on the relative humidity, to understand the underlying physicochemical phenomena and to build three dimensional maps of the wear coefficient as a function of both humidity and the product of normal force and sliding distance.
KW - Wear
KW - 100Cr6
KW - Relative humidity
PY - 2020
DO - https://doi.org/10.1016/j.wear.2020.203239
VL - 450-451
SP - 203239
AN - OPUS4-50583
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Legall, Herbert
A1 - Schwanke, Christoph
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - X-ray radiation protection aspects during ultrashort laser processing
N2 - Ultrashort pulse laser processing of materials allows for precise machining with high accuracy. By increasing the repetition rate to several 100 kHz, laser machining becomes quick and cost-effective. Ultrafast laser processing at high repetition rates and peak intensities above 10^13 W/cm^2 can cause a potential hazard by generation of unwanted x-ray radiation. Therefore, radiation protection must be considered. For 925 fs pulse duration at a center wavelength of 1030 nm, the x-ray emission in air at a repetition rate of 400 kHz was investigated up to a
peak intensity of 2.6 × 10^14 W/cm^2. Based on the presented measurements, the properties of potential shielding materials will be discussed. By extending our previous works, a scaling of the x-ray radiation emission to higher peak intensities up to 10^15 W/cm^2 is described, and emitted x-ray doses are predicted.
KW - Laser ablation
KW - Ultrashort pulse laser processing
KW - Laser-induced x-ray emission
KW - Radiation protection
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505677
DO - https://doi.org/10.2351/1.5134778
VL - 32
IS - 2
SP - 022004
AN - OPUS4-50567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Gefährdung durch Röntgenstrahlung bei der UKP-Lasermaterialbearbeitung
N2 - Der Vortrag beschreibt die Gefährdung durch die Erzeugung unerwünschter Röntgenstrahlung bei der Lasermaterialbearbeitung mit ultrakurzen Laserimpulsen. Die Einfluss der Laserparameter, der Prozessführung und die Materialabhängigkeit werden dargestellt.
T2 - Bayerische Laserschutztage 2020
CY - Nuremberg, Germany
DA - 21.01.2020
KW - Ultrakurze Laserimpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
PY - 2020
AN - OPUS4-50318
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vollert, F.
A1 - Thomas, Maximilian
A1 - Kromm, Arne
A1 - Gibmeier, J.
T1 - Hot crack assessment of LTT welds using μCT
N2 - Investigations on weldability often deal with hot cracking, as one of the most popular failure during weld fabrication. The modified varestraint transvarestraint hot cracking test (MVT) is well known for the assessment of the hot cracking susceptibility of materials. The shortcoming of this approach is that the information is only from the very near surface region, which inhibits access to the characteristic of the hot crack network in the bulk. Here, we report about a new approach, illustrated in the example of low transformation temperature (LTT) weld filler materials, to monitor the entire 3D hot crack network after welding by means of microfocus X-ray computer tomography (μCT).
T2 - 10th Conference on Industrial Computed Tomography (iCT 2020)
CY - Wels, Austria
DA - 04.02.2020
KW - Varestraint testing
KW - LTT weld filler materials
KW - Hot cracking
KW - Welding
KW - μCT-analysis
PY - 2020
DO - https://doi.org/https://doi.org/10.58286/25121
SN - 1435-4934
VL - 25
IS - 2
SP - 1
EP - 7
PB - NDT.net
CY - Kirchwald
AN - OPUS4-50341
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Petrushina, M.
A1 - Dedova, E.
A1 - Portnaygin, A.
A1 - Papynov, E.
A1 - Filatov, E.
A1 - Gubanov, A.
T1 - Pressure induced change in the ZrWMoO8
N2 - In this paper we report high-pressure synchrotron x-ray powder diffraction data for the cubic ZrWMoO8. For the first time, extensive structural study of ZrWMoO8 solid solution as a function of pressure was performed. This study shows that disordered cubic-ZrWMoO8 (space group Pa) transforms to ordered cubic-ZrWMoO8 (space group P) at low pressure. A further high-pressure influence leads followed by amorphization of the sample at 2.2 GPa. All transformations are irreversible. Our work will have high impact in the design of new composite materials with well-defined thermal expansion, especially for applications under extreme conditions and high mechanic stress.
KW - Phase transition
KW - High-pressure
KW - Complex oxides
PY - 2020
DO - https://doi.org/10.1016/j.matpr.2019.12.141
VL - 25
IS - 3
SP - 428
EP - 430
PB - Elsevier Ltd.
AN - OPUS4-50822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 49, Heft 4 & Band 50, Heft 1
T3 - Amts- und Mitteilungsblatt der BAM - 4/2019 & 1/2020
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
KW - Festlegungen
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508230
SN - 0340-7551
VL - 49 & 50
IS - 4/2019 & 1/2020
SP - 1
EP - 298
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-50823
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Florian, Camilo
A1 - Kirner, Sabrina V.
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Surface functionalization by laser-induced periodic surface structures
N2 - In recent years, the improved understanding of the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical, and chemical properties of many materials. Such structures strongly depend on the laser beam polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. The most accepted explanation for the origin of the structures is based on the interference of the incident laser radiation with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periods ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelengths, pulse durations and repetition rate laser sources, customized micro- and nanometric spatial resolutions, and compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces, and bacterial and cell growth for medical devices, among many others.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser processing
KW - Surface functionalization
KW - Applications
PY - 2020
DO - https://doi.org/10.2351/7.0000103
SN - 1938-1387
VL - 32
IS - 2
SP - 022063
PB - Laser Institute of America
AN - OPUS4-50780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Comparative analysis of error sources in the determination of wear volumes of oscillating ball-on-plane tests
N2 - The accurate determination of wear volumes is a prerequisite for the study of numerous tribological phenomena. Wear volumes can be measured with different techniques or else be calculated starting from some quantities measured from the wear scar. Advantages and drawbacks of the measuring techniques are shown by means of wear scars and calottes resulting from ball-on-plane tests with 100Cr6 specimens. When measuring wear volumes, white light interferometry results to be one of the most suitable techniques. When wear volumes are calculated, errors result mainly from two sources: (1) the arbitrary choice of one or few line profiles for the determination of the width and of the planimetric wear, and (2) approximations in the calculation, which are even necessary when values of the wear volumes of the single tribological partners and not only the total volume are of interest. The effect of both error sources on the accuracy in the determination of wear volumes is characterized and elucidated by examples. It is found that errors due to approximations are negligible when compared to errors due to the arbitrary choice of one line profile.
KW - Error sources analysis
KW - White light interferometry
KW - Statistical analysis
KW - AFM
KW - Wear
KW - Oscillating ball-on-disc test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508407
DO - https://doi.org/10.3389/fmech.2020.00025
VL - 6
SP - Article 25
AN - OPUS4-50840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuerlein, C.
A1 - Andrieux, J.
A1 - Michels, M.
A1 - Lackner, F.
A1 - Chiriac, R.
A1 - Hagner, M.
A1 - Di Michiel, M.
A1 - Meyer, Christian
A1 - Toche, F.
ED - Foley, C. P.
T1 - Effect of the fabrication route on the phase and volume changes during the reaction heat treatment of Nb3Sn superconducting wires
N2 - Accelerator magnets that can reach magnetic fields well beyond the Nb-Ti performance limits are presently being built and developed, using Nb3Sn superconductors. This technology requires reaction heat treatment (RHT) of the magnet coils, during which Nb3Sn is formed from its ductile precursor materials (a “wind and react” approach). The Nb3Sn microstructure and microchemistry are strongly influenced by the conductor fabrication route, and by the Phase changes during RHT. By combining in situ differential scanning calorimetry, high Energy synchrotron x-ray diffraction, and micro-tomography experiments, we have acquired a unique data set that describes in great detail the phase and microstructure changes that take place during the processing of restacked rod process (RRP), powder-in-tube (PIT), and internal tin (IT) Nb3Sn wires. At temperatures below 450 ° the phase evolutions in the three wire types are similar, with respectively solid state interdiffusion of Cu and Sn, Cu6Sn5 formation, and Cu6Sn5 peritectic transformation. Distinct differences in phase evolutions in the wires are found when temperatures exceed 450 °C. The volume changes of the conductor during RHT are a difficulty in the production of Nb3Sn accelerator magnets. We compare the wire diameter changes measured in situ by dilatometry with the phase and void volume evolution of the three types of Nb3Sn wire. Unlike the Nb3Sn wire length changes, the wire diameter evolution is characteristic for each Nb3Sn wire type. The strongest volume increase, of about 5%, is observed in the RRP wire, where the main diameter increase occurs above 600 °C upon Nb3Sn formation.
KW - Nb3Sn
KW - Microstructure
KW - Phase transformations
KW - Volume changes
KW - X-ray diffraction
KW - Differential scanning calorimetry
KW - Synchrotron micro-tomography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505128
DO - https://doi.org/10.1088/1361-6668/ab627c
VL - 33
IS - 3
SP - 034004
PB - IOP Publishing
CY - Bristol (UK)
AN - OPUS4-50512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Current topics and challenges in the forum of notified bodies
N2 - Es werden aktuelle Herausforderungen und Problemfälle im Forum der benannten Stellen für pyrotechnische Gegenstände nach der Richtlinie 2013/29/EU vorgestellt. Diese betrift maßgeblich: Wechsel der benannten Stellen, RRT, Kennzeichnung, Feuerwerksraketen, Transport, Konditionierung, Fehler, Module, Raucheffekte, Losprüfungen.
N2 - Current challenges and problems in the forum of notified bodies under the Directive 2013/29/EU are presented. This mainly comprises of: change of notified bodies, labelling, fireworks rockets, transport, conditioning, nonconformities, modules smoke effects and batch testing.
T2 - 16th Meeting of the AdCo Pyrotechnic Articles
CY - Leuven, Belgium
DA - 03.03.2020
KW - Batch testing
KW - Pyrotechnics
KW - Nonconformities
PY - 2020
AN - OPUS4-50513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rai, Alena
T1 - Volumetrische Ansprache von Grindingoberflächen
N2 - Seit einigen Jahren steht die Oberflächentexturierung der Betonfahrbahndecken mittels Grinding im Fokus der Forschung und Entwicklung des Betonstraßenbaus. Dabei wird das Ziel verfolgt, Grindingtechnologie zeitnah in das deutsche Regelwerk einzuführen und gegebenenfalls die Regelbauweise Waschbeton dadurch zu ersetzen. Im Rahmen der systematischen Erprobung konnte festgestellt werden, dass es, bedingt durch Beanspruchungen während der Nutzungsphase, zur Verbesserung bzw. Verschlechterung der relevanten Oberflächenperformances, wie z.B. Griffigkeit, Ebenheit oder Geräuschpegel kommt. Dies wird gegenwärtig mit den Texturgeometrieveränderungen in Verbindung gebracht. Vor diesem Hintergrund stellt sich zunächst die Frage, in wie weit die Grindingtextur und deren Veränderungen messtechnisch erfasst werden können und welche statistischen Kenngrößen dabei abgeleitet werden können. In diesem Zusammenhang ist eine Evaluation der dreidimensionalen messtechnischen Ansprache von Grindingoberflächen notwendig. Perspektivisch bedarf es einer Korrelationsanalyse zwischen der o.g. Texturkenngrößen mit Veränderungen der Oberflächenperformances.
Dieser Beitrag zeigt, dass mithilfe eines auf Streifenlichtprojektion basierenden Messsystems, eine hochaufgelöste volumetrische Erfassung der Oberflächentopografie verschiedener Grindingtexturen sowohl im Labor als auch in situ möglich ist. Darauf aufbauend galt es, die messtechnischen Voraussetzungen zur Gewährleistung reproduzierbarer Messungen zu schaffen. Dies ermöglicht eine Dokumentation der zeitlichen Texturveränderungen infolge verschieden-artiger Beanspruchungen. Basierend auf den Ergebnissen der 3D-Texturerfassung wurden Auswerteroutinen zur quantitativen und statistischen Charakterisierung der Oberflächentextur entwickelt. Zusätzlich wurden diese angewandt, um exemplarisch die Veränderungen der Oberflächentopographie infolge klimatischer Beanspruchung quantitativ abzubilden.
T2 - Workshop Grinding
CY - Bergisch Gladbach, Germany
DA - 28.01.2020
KW - Betonfahrbahndeckentexturen
KW - Grinding
KW - 3D-Texturerfassung
KW - Streifenlichtprojektionssystem
PY - 2020
AN - OPUS4-50449
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Aktuelle Ultrakurzpulslaser-Anwendungen an der BAM
N2 - Der Vortrag fasst aktuelle Anwendungsgebiete ultrakurzer Laserimpulse in der Materialbearbeitung zusammen. Dabei wird auch die Gefährdung durch unerwünschte Emission von Röntgenstrahlung bei der Überschreitung bestimmter Laserparameter thematisiert.
T2 - Anwendertreffen des Laserverbundes Berlin-Brandenburg e.V.
CY - Brandenburg, Germany
DA - 16.01.2020
KW - Ultrakurze Laserimpulse
KW - Materialbearbeitung
KW - Oberflächenstrukturierung
PY - 2020
AN - OPUS4-50317
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
T1 - Application of fracture mechanics to welds with crack origin at the weld toe—a review. Part 2: welding residual stresses. Residual and total life assessment
N2 - The two-part paper series provides an overview on the state-of-the-art in the application of engineering fracture mechanics to weldments limited to butt and fillet welds with crack initiation at weld toes. In the present second part, one focus is on welding residual stresses, their characteristics and stability under cyclic loading and their effect on structural integrity. Subsequently, features will be addressed which are essential for applying fracture mechanics to overall fatigue life and fatigue strength considerations of weldments. These comprise fatigue life relevant initial crack sizes and multiple crack initiation and Propagation due to various stress peaks along the weld toe. A concept is briefly introduced which covers all these aspects.
KW - Fracture mechanics
KW - Welding residual stresses
KW - Multiple crack propagation
KW - Fatigue strength
PY - 2020
DO - https://doi.org/10.1007/s40194-019-00816-y
VL - 64
IS - 1
SP - 151
EP - 169
PB - Springer
AN - OPUS4-50263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Cios, G.
A1 - Winkelmann, A.
T1 - Manual measurement of angles in backscattered and transmission Kikuchi diffraction patterns
N2 - A historical tool for crystallographic analysis is provided by the Hilton net, which can be used for manually surveying the crystal lattice as it is manifested by the Kikuchi bands in a gnomonic projection. For a quantitative analysis using the Hilton net, the projection centre as the relative position of the signal source with respect to the detector plane needs to be known. Interplanar angles are accessible with a precision and accuracy which is estimated to be ≤0.3o. Angles between any directions, e.g. zone axes, are directly readable. Finally, for the rare case of an unknown projection-centre position, its determination is demonstrated by adapting an old approach developed for photogrammetric applications.
It requires the indexing of four zone axes [uvw]i in a backscattered Kikuchi diffraction pattern of a known phase collected under comparable geometric conditions.
KW - Electron backscatter diffraction
KW - EBSD
KW - Angle measurement
KW - Gnomonic projections
KW - Kikuchi patterns
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507625
DO - https://doi.org/10.1107/S1600576720000692
VL - 53
SP - 435
EP - 443
AN - OPUS4-50762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Oertzen, Alexander
A1 - Wilrich, Cordula
T1 - GHS Einstufung von Explosivstoffen — Quo vadis?
N2 - Länderübergreifende und vereinheitlichte Kriterien zur Einstufung von gefährlichen Chemikalien und zu ihrer Gefahrenkommunikation sind ein wichtiges Element für die Sicherheit im Umgang mit Gefahrstoffen. Das globale System zur Einstufung und Kennzeichnung von Chemikalien – das Globally Harmonized System der Vereinten Nationen (UN) – oder kurz GHS – unterstützt dieses Anliegen und hat auch Eingang in die europäischen Rechtsvorschriften gefunden. Die Vereinten Nationen (UN) haben sich nunmehr einiger systematischer Probleme im GHS angenommen und verändern in diesem Zuge auch das Einstufungssystem für Explosivstoffe. Die Fachdiskussionen im Kreis der Experten bei UN sind komplex und nicht leicht zu verfolgen. Es soll daher hier ein Zwischenstand über die bislang vorliegenden Ergebnisse der damit befassten Arbeitsgruppen dargestellt werden.
KW - GHS
KW - Explosivstoffe
PY - 2020
SN - 0941-4584
VL - 2020
IS - 01
SP - 25
EP - 29
AN - OPUS4-50651
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aratsu, K.
A1 - Takeya, R.
A1 - Pauw, Brian Richard
A1 - Hollamby, M.J.
A1 - Kitamoto, Y.
A1 - Shimizu, N.
A1 - Takagi, H.
A1 - Haruki, R.
A1 - Adachi, S.
A1 - Yagai, S.
T1 - Supramolecular copolymerization driven by integrative self-sorting of hydrogen-bonded rosettes
N2 - Molecular recognition to preorganize noncovalently polymerizable supramolecular complexes is a characteristic process of natural supramolecular polymers, and such recognition processes allow for dynamic self-alteration, yielding complex polymer systems with extraordinarily high efficiency in their targeted function. We herein show an example of such molecular recognition-controlled kinetic assembly/disassembly processes within artificial supramolecular polymer systems using six-membered hydrogen-bonded supramolecular complexes (rosettes). Electron-rich and poor monomers are prepared that kinetically coassemble through a temperature-controlled protocol into amorphous coaggregates comprising a diverse mixture of rosettes. Over days, the electrostatic interaction between two monomers induces an integrative self-sorting of rosettes. While the electron-rich monomer inherently forms toroidal homopolymers, the additional electrostatic interaction that can also guide rosette association allows helicoidal growth of supramolecular copolymers that are comprised of an alternating array of two monomers. Upon heating, the helicoidal copolymers undergo a catastrophic transition into amorphous coaggregates via entropy-driven randomization of the monomers in the rosette.
KW - Self-assembly
KW - Coaggregation
KW - Scattering
KW - Simulation
KW - AFM
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506555
DO - https://doi.org/10.1038/s41467-020-15422-6
VL - 11
IS - 1
SP - Article number: 1623
PB - Springer Nature
AN - OPUS4-50655
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matz, R.
A1 - Rabe, Torsten
A1 - Töpfer, J.
A1 - Ziesche, S.
T1 - Circuit-Board-Integrated Transformers Design and Manufacture
N2 - Transformers couple two sections of a circuit by electromagnetic induction. They are widely used to either transform alternating voltage levels or to transmit power or signals across galvanic isolation. Both of these functions are essential for the operation of sensors and controllers. Covering all aspects from idea to circuit performance and from design to manufacture, this paper presents the first comprehensive description of the making of miniaturized, rugged, up-to-100W transformers for embedding into multilayer circuit boards. For circular coils, the well-manageable Ampere-Laplace law is shown to yield reliable designs, predicting correctly the performance of manufactured hardware. This enables fast design without lengthy finite element modelling. In the low-power linear regime, basic relations describe how the device’s characteristics evolve from the material properties and device structure. While scattering Parameters are useful for the analysis of isolated transformers with their intrinsic parasitics, the interaction with the components of the final circuit and the aspects of power and efficiency are addressed by chain matrixes.
While these design rules are similar for multilayer boards of different material (like epoxy, Teflon, ceramics), the manufacturing of ceramic board transformers is considered here in detail. Low-temperature-cofired ceramic (LTCC) boards being sintered at 900 °C are particularly suited for harsh environments with chemical or thermal stress as frequently found at sensor positions. The transformer performance usually benefits from or even requires an integrated ceramic core of higher permeability, a ferrite, to shape the magnetic flux. Methods to sinter ferrites inside a dielectric ceramic multilayerandto measure their performance are therefore described in detail.Asthe sintering behaviour of dielectricandmagnetic ceramics differs considerably, their simultaneous sintering is challenging.However, the sintering temperatures of the usefulMnZnand NiZnCu ferrites can be lowered to that of the dielectric material with only moderate loss of permeability by glass additives. Furthermore, thermal mismatch between materials causes catastrophic failure or at least stress and loss of magnetic performance during cooling to room temperature after sintering. This is avoidable by either adjusting the thermal expansion coefficient of the ferrite or by enclosing the ferrite between stressreleasing separation layers.We present the state of the art in materials development according to the first approach as well as fully functional devices made with the second technique.
Other applications not directly addressed but well related to this work are characterized by low load resistance in relation to the coil resistance of the transformer. Efficient power transmission then requires that technological solutions are applied to achieve the lowest possible resistive loss inside the coils by an enlarged conductor cross-section.
As this is particularly challenging for LTCC boards, a technique is discussed to fabricate conductor traces with a thickness larger than their width.
KW - Multilayer ceramic technology
KW - LTCC
KW - Transformer
PY - 2020
DO - https://doi.org/10.4416/JCST2019-00071
SN - 2190-9385
VL - 11
IS - 1
SP - 44
EP - 61
PB - Göller Verlag
CY - Baden-Baden
AN - OPUS4-50751
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkelmann, A.
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Nolze, Gert
A1 - Hielscher, R.
A1 - Koziel, T.
T1 - EBSD orientation analysis based on experimental Kikuchi reference patterns
N2 - Orientation determination does not necessarily require complete knowledge of the local atomic arrangement in a crystalline phase. We present a method for microstructural phase discrimination and orientation analysis of phases for which there is only limited crystallographic information available. In this method, experimental Kikuchi diffraction patterns are utilized to generate a self-consistent master reference for use in the technique of Electron Backscatter Diffraction (EBSD). The experimentally derived master data serves as an application-specific reference in EBSD pattern matching approaches. As application examples, we map the locally varying orientations in samples of icosahedral quasicrystals observed in a Ti40Zr40Ni20 alloy, and we analyse AlNiCo decagonal quasicrystals.
KW - EBSD
KW - Quasicrystal
KW - Crystal orientation
KW - Pattern matching
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507611
DO - https://doi.org/10.1016/j.actamat.2020.01.053
VL - 188
SP - 376
EP - 385
PB - Elsevier Ltd.
AN - OPUS4-50761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Bernsmeier, D.
A1 - Schmack, R.
A1 - Häusler, I.
A1 - Hertwig, Andreas
A1 - Kraffert, K.
A1 - Nissen, J.
A1 - Kraehnert, R.
T1 - Colloidal bimetallic platinum–ruthenium nanoparticles in ordered mesoporous carbon films as highly active electrocatalysts for the hydrogen evolution reaction
N2 - Hydrogen features a very high specific energy density and is therefore a promising candidate for clean fuel from renewable resources. Water electrolysis can convert electrical energy into storable and transportable hydrogen gas. Under acidic conditions, platinum is the most active and stable monometallic catalyst for the hydrogen evolution reaction (HER). Yet, platinum is rare and needs to be used efficiently. Here, we report a synthesis concept for colloidal bimetallic platinum–ruthenium and rhodium–ruthenium nanoparticles (PtRuNP, RhRuNP) and their incorporation into ordered mesoporous carbon (OMC) films. The films exhibit high surface area, good electrical conductivity and well-dispersed nanoparticles inside the mesopores. The nanoparticles retain their size, crystallinity and composition during carbonization. In the hydrogen evolution reaction (HER), PtRuNP/OMC catalyst films show up to five times higher activity per Pt than Pt/C/Nafion® and PtRu/C/Nafion® reference catalysts.
KW - Ordered mesoporous carbon
KW - Bimetallic noble metal nanoparticles
KW - Platinum-ruthenium colloid
KW - Electrolysis
KW - Hydrogen evolution reaction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506868
DO - https://doi.org/10.1039/C9CY02285F
SN - 2044-4753
VL - 10
IS - 7
SP - 2057
EP - 2068
PB - Royal Society of Chemistry
AN - OPUS4-50686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spranger, Felix
A1 - Schirdewahn, S.
A1 - Kromm, Arne
A1 - Merklein, M.
A1 - Hilgenberg, Kai
T1 - On the influence of TiB2, TiC, and TiN hard particles on the microstructure of localized laser dispersed AISI D2 tool steel surfaces
N2 - The control of friction and wear is a major concern in many industrial applications. A promising method for tailored surface modification is the so-called laser implantation technique. This method combines surface texturing and material optimization in one processing step by a localized dispersing of hard ceramic particles using pulsed laser radiation. Wear resistant, protruding micrometric features (implants) with defined geometry can be created in a deterministic pattern where needed on highly stressed surfaces, i.e., on forming or cutting tools.
However, in order to maintain the implants over the tool’s lifetime, a suitable selection of hard ceramic particles is a prerequisite. They must provide a defect-free metal matrix composite with a high share of homogeneously distributed particles and, especially, high implant hardness. In this study, TiN, TiC, and TiB2 hard particles were compared as implant materials for the first time. By a systematic variation of pulse power and pulse duration, their dispersing behavior and influence on the material properties of AISI D2 tool steel were investigated.
Although all powder materials had grain sizes smaller than 10 μm, it was possible to disperse them by pulsed laser radiation and to obtain defect-free protruding implants. The highest share of dispersed particles (∼64%) was observed for TiB2. By scanning electron microscopy and energy dispersive x-ray spectroscopy, it was also shown that a significant share of the preplaced particles was dissolved by the laser beam and precipitated as nanometer sized particles within the matrix during solidification. These in situ formed particles have a decisive influence on the material properties. While the TiN and TiC implants have shown maximum hardness values of 750 and 850 HV1, the TiB2 implants have shown the highest hardness values with more than 1600 HV1. By x-ray diffraction, it was possible to ascribe the lower hardness values of TiC and TiN implants to high amounts of retained austenite in the metal matrix. By implanting TiB2, the formation of retained austenite was successfully suppressed due to the in situ formation of TiC particles, which was proven by electron backscatter diffraction.
In conclusion, all the implant materials are basically suitable for laser implantation on AISI D2 tool steel. However, TiB2 has shown
the most promising results.
T2 - ICALEO 2019
CY - Orlando, FL, USA
DA - 07.10.2019
KW - Laser implantation
KW - Surface texturing
KW - AISI D2
KW - TiB2
KW - TiN
KW - TiC
KW - Retained Austenite
KW - Localized laser dispersing
PY - 2020
DO - https://doi.org/10.2351/7.0000059
VL - 32
IS - 2
SP - 022028
EP - 022028-9
PB - AIP Publishing
AN - OPUS4-50712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Spektor, K.
A1 - Khandarkhaeva, S.
A1 - Fedotenko, T.
A1 - Pakhomova, A.
A1 - Kupenko, I.
A1 - Rohrbach, A.
A1 - Klemme, S.
A1 - Crichton, W. A.
A1 - Dyachkova, T. V.
A1 - Tyutyunnik, A. P.
A1 - Zainulin, Y. G.
A1 - Gramilov, S. A.
A1 - Dubrovinsky, L. S.
T1 - Decomposition of single-source precursors under high-temperature highpressure to access osmium–platinum refractory alloys
N2 - Thermal decomposition of (NH4)2[OsxPt1-xCl6] as single-source precursors for Os-Pt binary alloys has been investigated under ambient and high pressure up to 40 GPa. Thermal decomposition of mixed-metal (NH4)2[OsxPt1-xCl6] precursor in hydrogen atmosphere (reductive environment) under ambient pressure results in formation of β-trans[Pt(NH3)2Cl2] and α-trans-[Pt(NH3)2Cl2] crystalline intermediates as well as single and twophase Os—Pt binary alloys. For the first time, direct thermal decomposition of coordination compound under pressure has been investigated. A formation of pure metallic alloys from single-source precursors under pressure has been shown. Miscibility between fcc- and hcpstructured alloys has been probed up to 50 GPa by in situ high-pressure X-ray diffraction. Miscibility gap between fcc- and hcp-structured alloys does not change its positions with pressure up to at least 50 GPa.
KW - High-pressure high-temperature
KW - Osmium
KW - Platinum
KW - Phase diagrams
KW - Alloys
KW - Single-source precursors
PY - 2020
DO - https://doi.org/10.1016/j.jallcom.2019.152121
VL - 813
SP - 152121
PB - Elsevier
AN - OPUS4-50019
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Medeiros, V.L.
A1 - Goulart de Araujo, L.
A1 - Ratero, D.R.
A1 - Paula, A.S.
A1 - Ferreira Molina, E.
A1 - Jaeger, Christian
A1 - Takehiro Marumo, J.
T1 - Synthesis and physicochemical characterization of a novel adsorbent based on yttrium silicate: A potential material for removal of lead and cadmium from aqueous media
N2 - A new metallosilicate based on yttrium was synthesized and characterized by XRD, FT-IR, 29Si MAS-NMR, and 89Y MAS-NMR. The mixed framework of the material was confirmed by the detection of distinct chemical shift groups using 29Si MAS-NMR (at -82 to -87 ppm, -91 to -94 ppm, -96 to -102 ppm, and -105 to -108 ppm), as well as four distinct chemical shifts in the 89Y MAS-NMR spectrum (at -89, -142, -160, and -220 ppm). Adsorption and kinetic analyses indicated the potential of the new material for the removal of lead and cadmium from aqueous media. The adsorption results for lead indicated that dynamic equilibrium was reached after five hours, with total lead removal of around 94 %, while for cadmium it was reached in the first hour, with total Cadmium removal of around 74 %. The adsorptions of lead and cadmium were modeled using pseudo-first order (PFO) and pseudo-second order (PSO) kinetic models. Although both models provided high R2 values (0.9903 and 0.9980, respectively), the PSO model presented a much lower χ2 red value (4.41×10−4), compared to the PFO model (2.12×10−3), which indicated that the rate-limiting step was probably due to the chemisorption of lead from the solution onto the yttrium-based metallosilicate.
KW - Yttrium silicates
KW - 29Si
KW - 89Y MAS-NMR
KW - Adsorption
KW - Chemisorption
KW - Cadmium and lead remediation
PY - 2020
DO - https://doi.org/10.1016/j.jece.2020.103922
VL - 8
SP - 103922
PB - Elsevier Ltd.
AN - OPUS4-51292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schiffmann, J.
A1 - Emmerling, Franziska
A1 - Martins, Ines
A1 - Van Wüllen, L.
T1 - In-situ reaction monitoring of a mechanochemical ball mill reaction with solid state NMR
N2 - We present an approach towards the in situ solid state NMR monitoring of mechanochemical reactions in a ball mill. A miniaturized vibration ball mill is integrated into the measuring coil of a home-built solid state NMR probe, allowing for static solid state NMR measurements during the mechanochemical reaction within the vessel. The setup allows to quantitatively follow the product evolution of a prototypical mechanochemical reaction, the formation of zinc phenylphosphonate from zinc acetate and phenylphosphonic acid. MAS NMR investigations on the final reaction mixture confirmed a reaction yield of 89% in a typical example. Thus, NMR spectroscopy may in the future provide complementary information about reaction mechanisms of mechanochemical reactions and team up with other analytical methods which have been employed to follow reactions in situ, such as Raman spectroscopy or X-ray diffraction.
KW - Mechanochemistry
KW - Solid state NMR
KW - NMR probe Development
PY - 2020
DO - https://doi.org/10.1016/j.ssnmr.2020.101687
VL - 109
SP - 101687
PB - Elsevier Inc.
AN - OPUS4-51283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Localized Laser Dispersing of Titanium-Based Particles for Improving the Tribological Performance of Hot Stamping Tools
N2 - Within the scope of this work, a new surface engineering technology named laser implantation has been investigated, in order to improve the tribological performance of hot stamping tools. This technique is based on manufacturing highly wear-resistant, separated, and elevated microfeatures by embedding hard ceramic particles into the tool surface via pulsed laser radiation.
Hence, the topography and material properties of the tool are modified, which influences the thermal and tribological interactions at the blank-die interface. To verify these assumptions and to clarify the cause–effect relations, different titanium-based particles (TiB2, TiC, TiN) were laser-implanted and subsequently analyzed regarding to their geometrical shape and mechanical properties. Afterwards, quenching tests as well as tribological experiments were carried out by using titanium-diboride as the most promising implantation material for reducing the tribological load due to high hardness value of the generated implants. Compared to conventional tooling systems, the modified tool surfaces revealed a significantly higher wear resistance as well as reduced friction forces while offering the possibility to adjust the thermal interactions at the blank-die interface. Based on these results, a tailored tool surface modification can be pursued in future research work, in order to enhance the effectiveness of the hot stamping technology.
KW - Hot stamping
KW - Tribology
KW - Surface modification
KW - Localized laser dispersing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510981
DO - https://doi.org/10.3390/jmmp4030068
VL - 4
IS - 3
SP - 68
PB - MDPI
AN - OPUS4-51098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Beck, Uwe
A1 - Fischer, Daniel
T1 - MISTRAL-Müller-Matrix-basierte Identifizierung von Inhomogenitäten und strukturellen Anomalien
N2 - Mit abbildender Ellipsometrie (imaging ellipsometry: IE) können Nanometer-Beschichtungen/ Degradationen visualisiert und bezüglich Brechungsindex n, Extinktionskoeffizient k und Schichtdicke d charakterisiert werden. Materialseitig werden lokal Homogenität und Isotropie innerhalb eines/mehrerer Bildpunkte (field of analysis: FOA) und messtechnisch global die Ebenheit der Proben bezüglich aller Bildpunkte des Messfeldes vorausgesetzt. Für die Müller-Matrix-basierte abbildende Ellipsometrie (MM-IE), die den optischen Response anisotroper Materialien in jedem Bildpunkt über die bis zu 16 Müller-Matrix-Elemente erfasst, ist dies von besonderer Relevanz. Reale Substrate sind aber oft nicht eben, können lokal Noppen/Mulden (im FOA) aufweisen oder sind global konvex/ konkav im möglichen Messfeld (field of view: FOV) gekrümmt. Diese lokalen/globalen strukturellen Anomalien des Substrats werden schon für die IE messtechnisch/modellseitig oft nicht beherrscht und sind für die MM-IE in der Wirkung auf die MM-Elemente unbekannt. Diese Defizite sollen messtechnisch bzw. modellmäßig behoben und somit die Messung lokal/global gekrümmter Oberflächen ermöglicht werden (MM-CSIE, CS curved surface).
KW - Abbildende Ellipsometrie (IE)
KW - Müller-Matrix Ellipsometrie (MM-IE)
KW - Gekrümmte Oberflächen
KW - Schichtdicke
KW - Optische Konstanten
PY - 2020
SP - 1
EP - 7
AN - OPUS4-51574
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
A1 - Mann, S.
A1 - Sharma, R.
A1 - Reisgen, U.
T1 - In-situ Identifikation der Schweißnahtgeometrie bei der Anwendung von MSG-Schweißprozessen
N2 - Lichtbogenbasierte Schweißverfahren wie das Metallschutzgasschweißen (MSG) zählen zu den Standardverfahren der Fügetechnik und werden in vielen Industriebereichen automatisiert unter Verwendung von Industrierobotern eingesetzt. Dabei können Schweißnahtabweichungen auftreten, die aus Änderungen der Prozessrandbedingungen und der hohen Prozessdynamik resultieren. Hier ist die Kontrolle von Schmelzbad- und Schweißnahtgeometrie für die Sicherung der Nahtqualität bedeutsam. Durch den Einsatz optischer Sensorsysteme können mit hoher zeitlicher Auflösung in-situ Informationen des Prozesszustands ermittelt werden. Dabei stellen die rauen Prozessbedingungen und die hohe Strahlungsintensität des Lichtbogens eine Herausforderung für die optischen Komponenten dar. Forschungsarbeiten am Institut für Schweißtechnik und Fügetechnik der RWTH Aachen haben gezeigt, dass durch den Einsatz einer HDR-Kamera in Kombination mit einer strukturierten Laserbelichtung gezielt geometrische Informationen des Lichtbogens und des Schmelzbads aus den Prozessaufnahmen gewonnen werden können. In dieser Arbeit wird eine parallele Schweißnaht- und Schmelzbadbeobachtung durchgeführt, wobei geometrische Informationen durch die Anwendung von Bildverarbeitungsalgorithmen extrahiert werden. Dabei wird ein nachlaufendes Sensorsystem eingesetzt, welches aus einer HDR-Kamera und einer Laserbeleuchtung besteht. Es werden diffraktive optische Elemente (DOE) zur Erzeugung von verschiedenen Laserprojektionsmustern verwendet, um sowohl eine unidirektionale als auch eine multidirektionale Prozessbeobachtung durchführen zu können. Aus den geometrischen Informationen werden Kenngrößen berechnet, anhand derer der Prozesszustand beurteilt werden kann. Es zeigt sich, dass anhand der Kenngrößenverläufe Abweichungen in der Schweiß- und Schmelzbadgeometrie und Positionierungsfehler des Roboters identifiziert werden können.
T2 - Große Schweißtechnische Tagung - DVS CAMPUS
CY - Online meeting
DA - 14.09.2020
KW - Schweißnahtgeometrie
KW - MSG-Schweißen
KW - In-situ Monitoring
KW - Schmelzbadbeobachtung
PY - 2020
SN - 978-3-96144-098-6
VL - 365
SP - 41
EP - 47
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-51576
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - In-situ Identifikation der Schweißnahtgeometrie bei der Anwendung von MSG-Schweißprozessen
N2 - Lichtbogenbasierte Schweißverfahren wie das Metallschutzgasschweißen (MSG) zählen zu den Standardverfahren der Fügetechnik und werden in vielen Industriebereichen automatisiert unter Verwendung von Industrierobotern eingesetzt. Dabei können Schweißnahtabweichungen auftreten, die aus Änderungen der Prozessrandbedingungen und der hohen Prozessdynamik resultieren. Hier ist die Kontrolle von Schmelzbad- und Schweißnahtgeometrie für die Sicherung der Nahtqualität bedeutsam. Durch den Einsatz optischer Sensorsysteme können mit hoher zeitlicher Auflösung in-situ Informationen des Prozesszustands ermittelt werden. Dabei stellen die rauen Prozessbedingungen und die hohe Strahlungsintensität des Lichtbogens eine Herausforderung für die optischen Komponenten dar. Forschungsarbeiten am Institut für Schweißtechnik und Fügetechnik der RWTH Aachen haben gezeigt, dass durch den Einsatz einer HDR-Kamera in Kombination mit einer strukturierten Laserbelichtung gezielt geometrische Informationen des Lichtbogens und des Schmelzbads aus den Prozessaufnahmen gewonnen werden können. In dieser Arbeit wird eine parallele Schweißnaht- und Schmelzbadbeobachtung durchgeführt, wobei geometrische Informationen durch die Anwendung von Bildverarbeitungsalgorithmen extrahiert werden. Dabei wird ein nachlaufendes Sensorsystem eingesetzt, welches aus einer HDR-Kamera und einer Laserbeleuchtung besteht. Es werden diffraktive optische Elemente (DOE) zur Erzeugung von verschiedenen Laserprojektionsmustern verwendet, um sowohl eine unidirektionale als auch eine multidirektionale Prozessbeobachtung durchführen zu können. Aus den geometrischen Informationen werden Kenngrößen berechnet, anhand derer der Prozesszustand beurteilt werden kann. Es zeigt sich, dass anhand der Kenngrößenverläufe Abweichungen in der Schweiß- und Schmelzbadgeometrie und Positionierungsfehler des Roboters identifiziert werden können.
T2 - Große Schweißtechnische Tagung - DVS CAMPUS
CY - Online meeting
DA - 14.09.2020
KW - Schweißnahtgeometrie
KW - MSG-Schweißen
KW - In-situ Monitoring
KW - Schmelzbadbeobachtung
PY - 2020
AN - OPUS4-51579
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
T1 - Application of contact-resonance AFM methods to polymer samples
N2 - Contact-resonance AFM (CR-AFM) has been used in recent years for the measurement of mechanical properties. Compared with other techniques, CR-AFM has a much shorter acquisition time, compensating the incomplete theoretical understanding of the underlying physical phenomena. In the present paper, we propose a procedure, which allows to determine the elastic modulus of the sample as a parameter of the fit of the CR frequency as a function of the load. It is concluded that CR measurements are not appropriate for polymer samples. Major drawbacks are the bad resolution for moduli lower than ca. 10 GPa and the lack of a comprehensive physical model.
KW - Atomic force microscopy
KW - Contact resonance
KW - Mechanical properties
KW - Polymers
KW - Wear
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515621
DO - https://doi.org/10.3762/bjnano.11.154
VL - 11
SP - 1714
EP - 1727
AN - OPUS4-51562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Genga, R. M.
A1 - Rokebrand, P.
A1 - Cornish, L. A.
A1 - Nelwalani, N.
A1 - Brandt, Guido
A1 - Kelling, Norbert
A1 - Woydt, Mathias
A1 - Janse van Vuuren, A.
A1 - Polese, C.
T1 - High-temperature sliding wear, elastic modulus and transverse rupture strength of Ni bonded NbC and WC cermets
N2 - The effects of rapid pulse electric current sintering (PECS), substitution of WC by NbC and Co by Ni, and carbide additives (TiC and Mo2C) on the microstructure, elastic modulus, B3B transverse rupture strength (TRS) and high temperature sliding wear on WC-Co, WC-Ni, NbC-Co and NbC-Ni cermets were studied. High temperature sliding wear tests were carried out using a ball-on-disk tribometer, with a 10 N force, at a sliding speed of 1.34 m/s for 0.8 km (10 min) and 2.4 km (30 min), using 100Cr6 (AISI 52100) steel balls at 400 °C and 0% humidity. Additions of TiC and Mo2C to NbC-12Ni improved the sliding wear resistance, with TiC having the greater effect, reducing the sample wear rate by over 30% from 15.1×10−6mm3/N·m to 9.4×10−6mm3/N·m after sliding distance of 2.4 km. Generally, the LPS samples had lower wear volumes than the corresponding SPS samples, due to higher K1c and TRS.
KW - Pulse electric current sintering
KW - Niobium carbide
KW - Nickel
KW - Molybdenum carbide
KW - Titanium carbide
PY - 2020
DO - https://doi.org/10.1016/j.ijrmhm.2019.105143
SN - 0263-4368
VL - 87
SP - 105143
PB - Elsevier Ltd.
AN - OPUS4-51473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lüth, Peter
A1 - Uhlig, S.
A1 - Frost, K.
A1 - Malow, Marcus
A1 - Michael-Schulz, Heike
A1 - Schmidt, Martin
A1 - Zakel, S.
T1 - CEQAT-DGHS interlaboratory tests for chemical safety: Validation of laboratory test methods by determining the measurement uncertainty and probability of incorrect classification including so-called “Shark profiles”
N2 - Laboratory test results are of vital importance for correctly classifying and labelling chemicals as “hazardous” as defined in the UN Globally Harmonized System (GHS) / EC CLP Regulation or as “dangerous goods” as defined in the UN Recommendations on the Transport of Dangerous Goods. Interlaboratory tests play a decisive role in assessing the reliability of laboratory test results. Interlaboratory tests performed over the last 10 years have examined different laboratory test methods. After analysing the results of these interlaboratory tests, the following conclusions can be drawn:
1. There is a need for improvement and validation for all laboratory test methods examined.
2. To avoid any discrepancy concerning the classification and labelling of chemicals, the use of validated laboratory test methods should be state of the art, with the results accompanied by the measurement uncertainty and (if applicable) the probability of incorrect classification.
This paper addresses the probability of correct/incorrect classification (for example, as dangerous goods) on the basis of the measurement deviation obtained from interlaboratory tests performed by the Centre for quality assurance for testing of dangerous goods and hazardous substances (CEQAT-DGHS) to validate laboratory test methods. This paper outlines typical results (e.g. so-called “Shark profiles” – the probability of incorrect classification as a function of the true value estimated from interlaboratory test data) as well as general conclusions and steps to be taken to guarantee that laboratory test results are fit for purpose and of high quality.
T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE 2020)
CY - Braunschweig, Germany
DA - 27.07.2020
KW - Dangerous goods
KW - Hazardous substances
KW - Interlaboratory test
KW - Test method
KW - Validation
KW - Quality assurance
KW - Measurement uncertainty
KW - Incorrect classification
KW - Shark profile
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515376
UR - https://oar.ptb.de/files/download/5f3e662f4c93901010006dbf
DO - https://doi.org/10.7795/810.20200724
VL - 2020
SP - 50
EP - 61
PB - Open Access Repository der Physikalisch-Technischen Bundesanstalt (PTB-OAR)
CY - Braunschweig
AN - OPUS4-51537
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lüth, Peter
T1 - CEQAT-DGHS Ringversuchprogramm für die Chemikaliensicherheit - Probleme bei der Generierung kleiner Durchflüsse für ein Verfahren zur Verifizierung der Prüfapparatur gemäß Prüfmethode UN Test N.5
N2 - Ob Explosion in einem Chemiewerk oder Brand auf einem Gefahrgutfrachter – die Ursachen für Unfälle können vielfältig sein. Prävention beginnt bereits im Prüflabor, wenn Chemikalien auf ihre gefährlichen Eigenschaften getestet werden.
Sicherheitsfachleute, Transporteure oder Händler müssen sich jedoch auf die richtige Durchführung der Prüfung und Bewertung verlassen können. Ringversuche, Referenzmaterialien, Verifizoierungsverfahren etc sind Mittel, um Prüfgeräte bzw. die Messergebisse auf ihre Zuverlässigkeit hin zu überprüfen.
Im Vortrag ein an der BM neu entwickeltes Verifizierungsfahren für das Prüfverfahren UN-N.5 vorgestellt. Es wird hierbei gezeigt, dass Schwebekörperdurchflussmesser (Rotameter) zur Messung kleiner Durchflüsses nicht ausreichend zuverlässig sind. Es wird deshalb die Entwicklung eines alternativen, gravimetrischen Verifizierungsverfahrens diskutiert.
T2 - BAM-PTB-Erfa Messung kleiner Durchflüsse
CY - Braunschweig, Germany
DA - 16.01.2020
KW - Gefahrgut
KW - Gefahrstoff
KW - Ringversuch
KW - Prüfmethode
KW - Verifizierung
KW - Validierung
KW - Messunsicherheit
KW - Qualitätsicherung
KW - UN Test N.5
PY - 2020
AN - OPUS4-51538
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Localized dispersing of TiB2 and TiN particles via pulsed laser radiation for improving the tribological performance of hot stamping tools
N2 - The aim of this study is to increase the tribological performance of hot stamping tools by using a laser implantation process. This technique allows the fabrication of separated, elevated and dome-shaped microfeatures on the tool surface in consequence of a localized dispersing of ceramic particles via pulsed laser radiation. Hence, the topography and material properties of the tool are modified, which influences the tribological interactions at the blank-die interface. However, an appropriate selection of ceramic particles is an essential prerequisite, in order to obtain tailored and highly wear resistant surface features. In this regard, different titanium-based hard particles (TiB2 and TiN) were laser-implanted on hot working tool specimens and subsequently tested by means of a modified pin-on-disk test regarding to their wear and friction behavior.
KW - Surface modification
KW - Tribology
KW - Laser implantation
KW - Hot working tool steel
KW - Hot stamping
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514171
DO - https://doi.org/10.1016/j.procir.2020.09.069
VL - 94
SP - 901
EP - 904
PB - Elsevier B.V.
AN - OPUS4-51417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cios, G.
A1 - Nolze, Gert
A1 - Winkelmann, A.
A1 - Tokarski, T.
A1 - Hielscher, R.
A1 - Strzalka, R.
A1 - Buganski, I.
A1 - Wolny, J.
A1 - Bala, P.
T1 - Approximant-based orientation determination of quasicrystals using electron backscatter diffraction
N2 - Orientation mapping of quasicrystalline materials is demonstrated using crystalline approximant structures in the technique of electron backscatter diffraction (EBSD). The approximant-based orientations are symmetrised according to the rotational point group of the quasicrystal, including the visualization of orientation maps using proper colour keys for quasicrystal symmetries. Alternatively, approximant-based orientation data can also be treated using pseudosymmetry post-processing options in the EBSD system software, which enables basic grain size estimations. Approximant-based orientation analyses are demonstrated for icosahedral and decagonal quasicrystals.
KW - EBSD
KW - Quasicrystal
KW - Approximant
KW - Chrystal orientation
KW - Data processing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514221
DO - https://doi.org/10.1016/j.ultramic.2020.113093
VL - 218
SP - 113093
PB - Elsevier B.V.
AN - OPUS4-51422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
T1 - Quo vadis LIPSS? - Recent and future trends on laser-induced periodic surface structures
N2 - Nanotechnology and lasers are among the most successful and active fields of research and technology that have boomed during the past two decades. Many improvements are based on the controlled manufacturing of nanostructures that enable tailored material functionalization for a wide range of industrial applications, electronics, medicine, etc., and have already found entry into our daily life. One appealing approach for manufacturing such nanostructures in a flexible, robust, rapid, and contactless one-step process is based on the generation of laser-induced periodic surface structures (LIPSS). This Perspectives article analyzes the footprint of the research area of LIPSS on the basis of a detailed literature search, provides a brief overview on its current trends, describes the European funding strategies within the Horizon 2020 programme, and outlines promising future directions.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Direct laser interference patterning (DLIP)
KW - Surface functionalization
KW - Literature survey
KW - European funding strategies
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513530
DO - https://doi.org/10.3390/nano10101950
SN - 2079-4991
VL - 10
IS - 10
SP - 1950-1
EP - 1950-19
PB - MDPI
CY - Basel
AN - OPUS4-51353
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Gräf, S.
T1 - Maxwell Meets Marangoni — A Review of Theories on Laser‐Induced Periodic Surface Structures
N2 - Surface nanostructuring enables the manipulation of many essential surface properties. With the recent rapid advancements in laser technology, a contactless large‐area processing at rates of up to m2 s−1 becomes feasible that allows new industrial applications in medicine, optics, tribology, biology, etc. On the other hand, the last two decades enable extremely successful and intense research in the field of so‐called laser‐induced periodic surface structures (LIPSS, ripples). Different types of these structures featuring periods of hundreds of nanometers only—far beyond the optical diffraction limit—up to several micrometers are easily manufactured in a single‐step process and can be widely controlled by a proper choice of the laser processing conditions. From a theoretical point of view, however, a vivid and very controversial debate emerges, whether LIPSS originate from electromagnetic effects or are caused by matter reorganization. This article aims to close a gap in the available literature on LIPSS by reviewing the currently existent theories of LIPSS along with their numerical implementations and by providing a comparison and critical assessment of these approaches.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Electromagnetic theories
KW - Matter reorganization theories
KW - Surface plasmon polaritons
KW - Self-organization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514089
DO - https://doi.org/10.1002/lpor.202000215
SN - 1863-8899
VL - 14
IS - 10
SP - 2000215-1
EP - 2000215-25
PB - Wiley
CY - Berlin
AN - OPUS4-51408
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schade, U.
A1 - Dawei, C.
A1 - Puskar, L.
A1 - Ritter, E.
A1 - Beckmann, Jörg
T1 - Removal of Etalon Features in the Far-Infrared–Terahertz Transmittance Spectra of Thin Polymer Films
N2 - Etalon features in infrared spectra of stratified samples, their influence on the interpretation and methods to circumvent their presence in infrared spectra have been in discussion for decades. This paper focuses on the application of a method originally developed to remove interference fringes in the mid-infrared spectra for far-infrared Fourier transform spectroscopy on thin polymer films. We show that the total transmittance-reflectance technique, commonly used for mid-infrared, also works successfully in the far infrared spectral range where other approaches fail. Experimental spectra obtained by such technique are supported by model calculations and reveal the possibility and limits to obtain almost undisturbed far-infrared spectra which are suitable to determine low energy vibrations of ionomer salts under certain sample conditions.
KW - Far-infrared spectroscopy
KW - Absorption
KW - Etalon feature
KW - Total transmittance reflectance
PY - 2020
DO - https://doi.org/10.1177/0003702820922295
VL - 74
IS - 12
SP - 1530
EP - 1539
PB - Sage journals
AN - OPUS4-51367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koclega, Damian
A1 - Radziszewska, A.
A1 - Dymek, S.
A1 - Morgiel, J.
A1 - Maj, L.
A1 - Kranzmann, Axel
T1 - Improvement of Corrosion Resistance of 13CrMo4-5 Steel by Ni-Based Laser Cladding Coatings
N2 - The 13CrMo4-5 ferritic steel is commonly used in power plants, due to its favorable mechanical properties. According to EN 10028-2, this steel can be used at temperatures up to 570°C because of its creep behavior. The inefficient corrosion resistance limits the application of this steel to lower temperatures depending on the gas temperature and slag formation. Therefore, the application of a highly resistant Ni-based coating is proposed to extend the corrosion resistance of elements made of ferritic steel. The corrosion test was performed in an environment containing a mixture of gases, like O2, COx, and SOx, and deposited ashes with elements, e.g., Na, Cl, Ca, Si, C, Fe, and Al. The exposure time was, respectively, 240 h, 1000 h and 4500 h at a temperature of 600°C. The oxide scale formed on the 13CrMo4-5 steel was significantly thicker than on the IN686 coating. The microstructure and chemical and phase compositions of the oxide scale were investigated using light optical microscopy together with scanning and transmission electron microscopy techniques. Energy dispersive x-ray analyses were performed when appropriate.
KW - Aggressive environments
KW - Corrosion resistance
KW - High - temperature
KW - Inconel 686
KW - Laser cladding
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514289
DO - https://doi.org/10.1007/s11665-020-04867-x
SN - 1059-9495
VL - 29
IS - 6
SP - 3702
EP - 3713
PB - Springer
AN - OPUS4-51428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherb, T.
A1 - Fantin, Andrea
A1 - Checcia, S.
A1 - Stephan-Scherb, Christiane
A1 - Escolástico, S.
A1 - Franz, A.
A1 - Seeger, J.
A1 - Meulenberg, W. A.
A1 - d'Acapito, F.
A1 - Serra, J. M.
T1 - Unravelling the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d mixed ionic electronic conductors
N2 - Mixed ionic electronic conducting ceramics Nd6-yWO12-d (d is the Oxygen deficiency) provide excellent stability in harsh environments containing strongly reactive gases such as CO2, CO, H2, H2O or H2S. Due to this chemical stability, they are promising and cost-efficient candidate materials for gas separation, catalytic membrane reactors and protonic ceramic fuel cell technologies. As in La6-yWO12-d, the ionic/electronic transport mechanism in Nd6-yWO12-d is expected to be largely controlled by the crystal structure, the conclusive determination of which is still lacking. This work presents a crystallographic study of Nd5.8WO12-d and molybdenum-substituted Nd5.7W0.75Mo0.25O12-d prepared by the citrate complexation route. High-resolution synchrotron and neutron powder diffraction data were used in combined Rietveld refinements to unravel the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d. Both investigated samples crystallize in a defect fluorite crystal structure with space group Fm3m and doubled unit-cell parameter due to cation ordering. Mo replacesWat bothWyckoff sites 4a and 48h and is evenly distributed, in contrast with La6-yWO12-d. X-ray absorption spectroscopy as a function of partial pressure pO2 in the near-edge regions excludes oxidation state changes of Nd (Nd3+) and W(W6+) in reducing conditions: the enhanced hydrogen permeation, i.e. ambipolar conduction, observed in Mo-substituted Nd6-yWO12-d is therefore explained by the higher Mo reducibility and the creation of additional – disordered – oxygen vacancies.
KW - Powder diffraction
KW - Mixed conductors
KW - X-ray absorption spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514607
DO - https://doi.org/10.1107/S1600576720012698
VL - 53
SP - 1471
EP - 1483
AN - OPUS4-51460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Wolfgang
A1 - Stockmann, Jörg M.
A1 - Senoner, Mathias
A1 - Weimann, T.
A1 - Bütefisch, S.
A1 - Passiu, C.
A1 - Spencer, N. D.
A1 - Rossi, A.
T1 - Introduction to lateral resolution and analysis area measurements in XPS
N2 - Imaging and small-spot (small area) XPS have become increasingly important components of surface chemical analysis during the last three decades, and its use is growing. Some ambiguity in the use of terminology, understanding of concepts, and lack of appropriate reference materials leads to confusing and not always reproducible data. In this paper, it is shown that by using existing knowledge, appropriate test specimens, and standardized approaches, problems of comparability and such reproducibility issues recently observed for XPS data reported in the scientific literature can be overcome. The standardized methods of ISO 18516:2019, (i) the straight-edge, (ii) the narrow-line, and (iii) the grating method, can be used to characterize and compare the lateral resolution achieved by imaging XPS instruments and are described by reporting examples. The respective measurements are made using new test specimens. When running an XPS instrument in the small-spot (small area) mode for a quantitative analysis of a feature of interest, the question arises as to what contribution to the intensity originates from outside the analysis area. A valid measurement approach to control the intensity from outside the nominal analysis area is also described. As always, the relevant resolution depends on the specific question that needs to be addressed. The strengths and limitations of methods defining resolution are indicated.
KW - Imaging XPS
KW - Lateral resolution
KW - Analysis area measurements
KW - Small-spot XPS
PY - 2020
DO - https://doi.org/10.1116/6.0000398
VL - 38
IS - 5
SP - 053206
AN - OPUS4-51394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krautz, M.
A1 - Beyer, L.
A1 - Funk, Alexander
A1 - Waske, Anja
A1 - Weise, B.
A1 - Freudenberger, J.
A1 - Gottschall, T.
T1 - Predicting the dominating factors during heat transfer in magnetocaloric composite wires
N2 - Magnetocaloric composite wires have been studied by pulsed-field measurements up to μ0ΔH = 10 T with a typical rise time of 13 ms in order to evaluate the evolution of the adiabatic temperature change of the core, ΔTad, and to determine the effective temperature change at the surrounding steel jacket, ΔTeff, during the field pulse. An inverse thermal hysteresis is observed for ΔTad due to the delayed thermal transfer. By numerical simulations of application-relevant sinusoidal magnetic field profiles, it can be stated that for field-frequencies of up to two field cycles per second heat can be efficiently transferred from the core to the outside of the jacket. In addition, intense numerical simulations of the temperature change of the core and jacket were performed by varying different parameters, such as frequency, heat capacity, thermal conductivity and interface resistance in order to shed light on their impact on ΔTeff at the outside of the jacket in comparison to ΔTad provided by the core.
KW - Composite
KW - Heat transfer
KW - Numerical simulation
KW - Pulsed magnetic field
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513791
DO - https://doi.org/10.1016/j.matdes.2020.108832
VL - 193
SP - 108832
PB - Elsevier Ltd.
AN - OPUS4-51379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Adhesion of Coatings vs. Strength of Composite Materials – A Review of Applications Evaluated by Centrifugal Adhesion Testing (CAT)
N2 - Sufficient adhesion/tensile strength are basic requirements for any coating/composite material. For coatings, adhesive strength in N/mm2 is of Major interest for various applications such as decorative and water-repellent coatings on wood (paints and varnishes), optical coatings on glass and polymers (reflectors and filters), electrical coatings on semiconductors, glass and polymers (conducting and bondable layers), mechanical coatings on metals and polymers (wear-reduction, scratch-resistance) and adhesion-promoting layers. For composite materials, tensile strength in N/mm2 is also a key quantity for carbon fiber reinforced composites (CFC), laminates and adhesive-bonded joints. Centrifugal adhesion testing (CAT) transfers the single-sample tensile test from a tensile or universal testing machine into an analytical centrifuge as multiple-sample test of up to eight test pieces. The one-sided sample support instead of a two-sided sample clamping and the absence of mounting- and testing-correlated shear forces provides fast and reliable results both for adhesive strength and bonding strength by means of bonded test stamps. For bonding strength, the evaluation of failure pattern from microscopic inspection is required in order to determine the failure pattern according to ISO 10365 such as adhesive failure (AF), delamination failure (DF) and cohesive failure (CF). Hence, one test run by CAT-technology provides either statistics or ranking of up to eight samples at once. For adhesive strength of coatings, a variety of examples is discussed such as ALD-Al203 layers as adhesion promoters, evaporated Ag-layers on N-BK7 glass, sputtered Cr- and Al-layers on Borofloat 33 glass, evaporated Au-films on N-BK7 glass and sputtered SiO2 -layers on CR39 Polymer. Provided adhesive or bonding strength are high enough, the substrate or the joining part may also fail.
T2 - Special PSE 2020
CY - Online meeting
DA - 07.09.2020
KW - Centrifugal adhesion testing (CAT)
KW - Adhesive strength
KW - Pull-off test
KW - Failure pattern
KW - Compound strength
PY - 2020
AN - OPUS4-51231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, Silke
A1 - Kurth, Lutz
T1 - Wege zur richtigen Beurteilung von Gefährdungen - Unfalluntersuchung eines schwarzpulverähnlichen Reinigungspulvers
N2 - Bei der Explosion in einer Herstellungsstätte für ein Pulver zur Reinigung industrieller Feuerungsanlagen ist eine Person tödlich verunglückt. Die BAM wurde gebeten, beschlagnahmte Muster des Reinigungspulvers zu bewerten. Dafür wurden verschiedene Untersuchungen durchgeführt. Diese sollten klären, ob die stoffliche Einstufung des Reinigungspulvers in die Klasse 5.1 für die sichergestellten Pulverproben zutreffend ist. Es konnte nachgewiesen werden, dass die untersuchten Pulverproben explosionsgefährliche Eigenschaften aufweisen und der Klasse 1 zuzuordnen sind. Die weiterführende Gefährdungsbeurteilung erfolgte anhand neu eingeführter sicherheitstechnischer Kenndaten Kriterien und der daraus abgeleiteten Gefahrgruppe.
KW - Gefährdung
KW - Kenndaten
KW - Gefahrgruppen
PY - 2020
SN - 0941-4584
IS - 2
SP - 15
EP - 21
PB - Deutscher Sprengverband
CY - Siegen
AN - OPUS4-51146
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rawat, S. S.
A1 - Harsha, A. P.
A1 - Khatri, O. P.
A1 - Wäsche, Rolf
T1 - Pristine, reduced, and alkylated graphene oxide as additives to paraffin grease for enhancement of tribological properties
N2 - Pristine, reduced, and alkylated graphene oxides are applied as lubricating additives in paraffin grease. It has revealed that their crystalline structure governs the tribological properties of grease for steel tribo-pair. The microstructural analyses of grease samples showed that a loose fiber network of soap in the presence of graphene-based additive allows their facile release for efficient lubrication. The surface analyses based on the microscopic and elemental mapping show the development of a graphene-derived protective film on the worn scars, which protected the tribo-surfaces and subsided the wear. The reduced graphene oxide (rGO) with the interlamellar distance of 0.35 nm in the (002) plane provided minimum resistance to shear and exhibited maximum reduction in coefficient of friction (COF) for the paraffin grease. The presence of oxygen functionalities in the basal of pristine and alkylated graphene oxide (GO) compromised the interlamellar shearing under tribo-stress; consequently, higher COF than that of rGO.
KW - Coefficient of friction
KW - Graphene oxide
KW - Grease
KW - Nanoadditive
KW - Tribo-film
KW - Wear
KW - Boundary lubrication
KW - Grease lubrication
KW - Lubricant additives
KW - Lubricants
PY - 2021
DO - https://doi.org/10.1115/1.4047952
VL - 143
IS - 2
SP - 021903-1
EP - 021903-11
PB - ASME
AN - OPUS4-51170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hielscher-Bofinger, Stefan
A1 - Beck, Uwe
T1 - Multiple-sample Testing: Adhesive Strength of Coatings and Bonding Strength of Adhesives evaluated by Centrifugal Adhesion Testing (CAT)
N2 - The quantitative determination of adhesion and cohesion properties is a key requirement for adhesive-bonded joints and coated components in both R&D and Quality assurance. Because of the huge variety of layer/substrate Systems in terms of materials and large thickness range, adhesion tests display the same diversity as layer/substrate systems. There are only two tensile testing procedures available, that determine adhesive strength in terms of force per area (N/mm²), the single-sample pull-off test in a tensile testing machine and the multiple-sample-test using the Centrifugal Adhesion Testing (CAT) Technology.
The CAT Technology is a testing method which uses centrifugal force as tensile testing force in a multiple-sample arrangement within a drum rotor of a Desktop centrifuge. Hence, the adhesive/bonding strength A/B can be determined on a statistical basis under identical testing conditions for up to eight samples.
A variety of examples for bonding strength of adhesives, adhesive strength of coatings and compound strength of composite materials is discussed such as metalto-metal and glass-to-metal bonding, sputtered SiO2-layers on CR39 Polymer and carbon fiber reinforced polymer.
T2 - Colloquium Department 6.
CY - Berlin, BAM, Germany
DA - 03.09.2020
KW - Centrifugal Adhesion Testing (CAT)
KW - Adhesive strength
KW - Bonding strength
KW - Composite strength
KW - Interlaboratory comparision
PY - 2020
AN - OPUS4-51178
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lone, S. A.
A1 - Muck, M.
A1 - Fosodeder, P.
A1 - Mardare, C.C.
A1 - Florian, Camilo
A1 - Weth, A.
A1 - Krüger, Jörg
A1 - Steinwender, C.
A1 - Baumgartner, W.
A1 - Bonse, Jörn
A1 - Heitz, J.
A1 - Hassel, A.W.
T1 - Impact of Femtosecond Laser Treatment Accompanied with Anodization of Titanium Alloy on Fibroblast Cell Growth
N2 - Herein, Ti6Al4V alloy is surface modified by femtosecond laser ablation. The microstructure image obtained by secondary electron microscopy reveals a combination of micrometer spikes or cones superimposed by nanoripples (laser‐induced periodic surface structures). To make the surface hydrophilic, anodization is performed resulting in further smoothness of microstructure and a final thickness of 35 ± 4 nm is estimated for oxide produced after anodization at 10 V (scan rate = 0.1 V s−1) versus standard hydrogen electrode. The obtained electrochemically active surface area (ECSA) is approximately 8 times larger compared with flat mirror polished Ti6Al4V surface. Combined chemical analysis by Pourbaix diagram and X‐ray photoelectron spectroscopy (XPS) analyses reveal that titanium and aluminum are passivating into TiO2 and Al2O3, but the dissolution of aluminum in the form of solvated ion is inevitable. Finally, cell seeding experiments on anodized and laser‐treated titanium alloy samples show that the growth of murine fibroblast cells is significantly suppressed due to unique surface texture of the laser‐treated and anodized titanium alloy sample.
KW - Anodization
KW - Femtosecond laser ablation
KW - Laser-induced periodic surface structures, LIPSS
KW - Ti6Al4V alloys
KW - X-ray photoelectron spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510263
DO - https://doi.org/https://doi.org/10.1002/pssa.201900838
SN - 1862-6300
SN - 1862-6319
VL - 217
IS - 13
SP - 1900838-1
EP - 1900838-9
PB - WILEY-VCH Verlag
CY - Weinheim, Germany
AN - OPUS4-51026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
A1 - Gardei, André
A1 - Hoppe, Johannes
A1 - Meng, Birgit
ED - Littmann, K.
T1 - Funktionalisierung von Fasern für zementgebundene Materialien - ausgewählte Prüfmethoden
N2 - Die geringe Zugfestigkeit von zementgebundenen Materialien kann durch die Zugabe von Fasern maßgeblich verbessert werden. Ziel eines gemeinsamen Verbundprojekts mit einem Industriepartner war die Erhöhung der Leistungsfähigkeit von kurzen Polymer- und Carbonfasern durch eine Verbesserung des Verbundes zwischen Faseroberfläche und Zementsteinmatrix.
Von der IONYS AG wurde dazu eine spezielle Funktionalisierung entwickelt, die über eine Hydrophilisierung der Faseroberfläche eine chemische Anbindung an die Zementsteinmatrix gewährleistet. Aufgabe der BAM war es, die Effizienz der neuen Beschichtung bezüglich der Erhöhung der Nachrissbiegezugfestigkeit und der Reduzierung der Schwindrissbildung während der Erhärtungsphase zu quantifizieren. Die Ergebnisse zeigen, dass die Funktionalisierung die Neigung zur Schwindrissbildung für die Carbonfasern und in noch stärkerem Maße für die Polymerfasern reduziert.
Eine Erhöhung der Nachrissbiegezugfestigkeit konnte dagegen nur für die deutlich steiferen Carbonfasern nachgewiesen werden.
T2 - 10. Kolloquium Industrieböden
CY - Esslingen, Germany
DA - 03.03.2020
KW - Fibres
KW - Cementitious materials
KW - Shrinkage
KW - Strain hardening
PY - 2020
SN - 978-3-8169-3505-6
SP - 173
EP - 178
PB - expert Verlag GmbH
CY - Tübingen
AN - OPUS4-51915
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
T1 - Composite materials - focus polymer matrix composites (PMC)
N2 - Lecture about polymer matrix composites as part of the first trainings event GW4SHM, properties, production, basic theory, testing.
T2 - 1. Training GW4SHM-Project
CY - BAM, Berlin, Germany
DA - 23.11.2020
KW - Polymer matrix composites
KW - Composite testing
KW - NDT
PY - 2020
AN - OPUS4-51868
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nolze, Gert
T1 - Lattice parameter determination with EBSD. Is that possible?
N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined.
T2 - Institutskolloquium Kassel
CY - Online meeting
DA - 30.10.2020
KW - Phasenidentifikation
KW - EBSD
KW - Gitterkonstanten
PY - 2020
AN - OPUS4-51813
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
T1 - Trends in Materials Informatics
N2 - Many PhD students are interested in applying machine learning, AI, data science, etc., and there are many good reasons for this. However, there is a disconnect between mainstream data science and materials science, for example, when it comes to the sheer size of the data. This talk will highlight some of the unique challenges in materials informatics and present some interesting approaches to overcome them. Although the field is large, this talk will focus on cases that have some practical relevance to PhD students at BAM.
T2 - PhD Day at BAM 2020
CY - Online meeting
DA - 15.09.2020
KW - Materials Informatics
KW - Small Data
PY - 2020
AN - OPUS4-51814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy Harvesting Using Thermomagnetic Generators with Magnetocaloric Materials
N2 - To date, there are only very few technologies available for the conversion of low temperature waste heat to electricity. More than a century ago, thermomagnetic generators were proposed, which are based on a change of magnetization with temperature, switching a magnetic flux, which according to Faraday’s law induces a voltage. In this talk, we first describe the principle of thermomagnetic generators. Then we focus on the impact of topology of the magnetic circuit within thermomagnetic generators. We demonstrate that the key operational parameters strongly depend on the genus, i.e. the number of holes within the magnetic circuit. A pretzel-like topology of the magnetic circuit with genus =3 improves the performance of thermomagnetic generators by orders of magnitude. We will show that this technique is on its way to becoming competitive with thermoelectrics for energy harvesting near room temperature.
T2 - TMS Annual Meeting
CY - San Diego, CA, USA
DA - 23.02.2020
KW - Materials science
KW - Energy harvesting
PY - 2020
AN - OPUS4-51903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Materials for Thermomagnetic Harvesting of Low Temperature Waste Heat:
N2 - Thermomagnetic materials are a new type of magnetic energy materials, which enable the conversion of low temperature waste heat to electricity by three routes: Thermomagnetic motors, generators and microsystems. Taking our recent work on thermomagnetic generators as a starting point, in this talk we analyse the material requirements for a more energy and economic efficient conversion. We will describe the influence of magnetisation change and heat capacity on thermodynamic efficiency, as well as the consequences of thermal conductivity on power density. Our analysis will allow selecting the best thermomagnetic materials in Ashby plots and illustrate the substantial different properties compared to magnetocaloric materials. Supported by DFG, project FA 453/14)
T2 - TMS Annual Meeting
CY - San Diego, CA, USA
DA - 23.02.2020
KW - Materials science
KW - Energy harvesting
PY - 2020
AN - OPUS4-51904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yu, C.-H.
A1 - Peng, R. L.
A1 - Luzin, V.
A1 - Sprengel, Maximilian
A1 - Calmunger, M.
A1 - Lundgren, J.-E.
A1 - Brodin, H.
A1 - Kromm, Arne
A1 - Moverare, J.
T1 - Thin-wall effects and anisotropic deformation mechanisms of an additively manufactured Ni-based superalloy
N2 - Laser powder bed fusion (LPBF) of Ni-based superalloys shows great potential for high temperature applications, for example, as a burner repair application for gas turbines where the thin-walled structure is important. It motivates this work to investigate the evolution of microstructure and the anisotropic mechanical behavior when plate-like specimens are built with a thickness from 4 mm down to 1 mm. By performing texture analysis using neutron diffraction, a clear transition in fiber texture from <011> to <001> is indicated when the specimen becomes thinner. The residual stress shows no thickness dependence, and at the subsurface the residual stress reaches the same level as the yield strength. Due to the rough as-built surface, a roughness compensation method for mechanical properties of thin-walled structures is outlined and demonstrated. Tensile tests from room temperature up to 700 ◦C have been carried out. Anisotropic mechanical behavior is found at all temperatures, which is strongly related to the anisotropic texture evolution. Stronger texture evolution and grain rotations are discovered when the tensile loading is applied along the building direction. The mechanical behavior has been compared to a wrought material, where the high dislocation density and the subgrain structure of the LPBF material result in a higher yield strength. Combining the statistical texture analysis by neutron diffraction with mechanical testing, EBSD grain orientation mapping and the investigation of dislocation structures using transmission electron microscopy, this work illustrates the significance of texture for the thin-wall effect and anisotropic mechanical behavior of LPBF materials.
KW - Hastelloy X
KW - Hot tensile test
KW - Crystallographic texture
KW - Roughness
KW - Residual stress
KW - Dislocation density
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518759
DO - https://doi.org/10.1016/j.addma.2020.101672
VL - 36
SP - 101672
PB - Elsevier B.V.
AN - OPUS4-51875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, David
T1 - From W. C. Röntgen to modern Tomography
N2 - A not complete review of X-Ray related milestones from 1895 to the 21st century.
T2 - ITN GW4SHM, First Training Event
CY - Online Meeting
DA - 23.11.2020
KW - X-Ray
KW - Computed Tomography
KW - Laminography
KW - Digital Detector Arrays
KW - Wilhelm Conrad Röntgen
PY - 2020
AN - OPUS4-51881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Léonard, Fabien
T1 - Overview of XCT data processing workflow for ammonium nitrate prills quantitative analysis
N2 - This video presents the data processing workflow that was developed to perform the quantitative structural and morphological analysis of ammonium nitrate prills by x-ray computed tomography.
KW - ANFO
KW - Data processing
KW - Explosives
KW - Porosity
KW - Surface area
KW - XCT
PY - 2020
DO - https://doi.org/10.5281/zenodo.3611339
PB - Zenodo
CY - Geneva
AN - OPUS4-51897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heßmann, Jennifer
A1 - Bachmann, Marcel
A1 - Hilgenberg, Kai
T1 - Numerical and experimental investigation of controlled weld pool displacement by electromagnetic forces for joining dissimilar materials
N2 - In order to reduce CO2 emissions, an increasing interest in lightweight construction exists in the automotive industry, especially the multi-material-design approach. The main construction materials here are steels and aluminium alloys. Due to their different physical material properties and limited mutual solubility, these two materials cannot be joined thermally without difficulty. This paper presents a new joining approach for dissimilar materials. It uses electromagnetic displacement of a laser-generated melt pool to produce overlap joints between 1 mm steel (1.0330) and 2 mm aluminium alloy (EN AW 5754). Contactless induced Lorentz forces are generated by an alternating current (AC) magnet system. The controlled displacement of the aluminium alloy melt into the hole of the overlying steel sheet is investigated through numerical and experimental studies. The numerical results are compared with cross sections and thermocouple measurements. For the first time, it is possible to achieve a reproducible controlled melt pool displacement on thin sheets to produce overlap joints between dissimilar materials.
KW - Displacement
KW - Laser beam welding
KW - Dissimilar materials
KW - Joining technology
KW - Electromagnetic field
KW - Lorentz force
KW - Numerical investigation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516640
DO - https://doi.org/10.3390/met10111447
VL - 10
IS - 11
SP - 1447
EP - 1462
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-51664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Anja
A1 - Possling, A.
A1 - Malysheva, N.
A1 - Yousef, K. P.
A1 - Herbst, S.
A1 - von Kleist, M.
A1 - Hengge, R.
T1 - Local c-di-GMP signaling in the control of synthesis of the E. coli biofilm exopolysaccharide pEtN-cellulose
N2 - In many bacteria, the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of "local" c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC and a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modeling and simulation, we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.
KW - Biofilm
KW - Cellulose synthase
KW - Bacterial second messenger
KW - C-di-GMP
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511214
DO - https://doi.org/10.1016/j.jmb.2020.06.006
SN - 0022-2836
VL - 432
IS - 16
SP - 4576
EP - 4595
PB - Elsevir Ltd.
AN - OPUS4-51121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
T1 - Prozesssimulation elektromagnetischer Kräfte zum Fügen artungleicher Werkstoffe
N2 - Prozesssimulation zur Eingrenzung der elektromagnetischen Kräfte zum gezielten Verdrängen einer laserstrahlinduzierten Schmelze zum Fügen artungleicher Materialien. Berechnung der Lorentzkraftverteilung im Schmelzbad. Abschätzung der Temperaturentwicklung beim Verdrängungsprozess.
T2 - Assistentenseminar der WGF 2020
CY - Online meeting
DA - 01.09.2020
KW - Artungleiche Werkstoffe; Elektromagnetische Schmelzbadbeeinflussung; Fügetechnologie; Laserstrahlschweißen; Stahl und Aluminium
PY - 2020
AN - OPUS4-51666
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beckmann, Jörg
T1 - Novel Technique for On-Line Monitoring of the Curing Process of Fiber Reinforced Polymer Composites
N2 - A specially designed experimental set up has been integrated into a commercially available FT IR Spectrometer for ATR experiments on Epoxy Systems. Representative data of far infrared spectra measured during the curing process at different temperatures of an epoxy system will be presented in dependency of the curing situation. The experiments and the selected set up are discussed to demonstrate its potential for future monitoring and ageing control applications during a manufacturing process of polymer composites.
T2 - 45. International Confercene on infrared, milimeter and terahertz waves
CY - Online meeting
DA - 08.11.2020
KW - Far-infrared spectroscopy
KW - Curing Monitoring
PY - 2020
UR - https://live-irmmwthz.pantheonsite.io/technical-program
AN - OPUS4-51649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
T1 - Evaluation of Advanced NDT-Methods for Measurement of Fibre Orientation in Concrete
N2 - Integration of fibre reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel fibre reinforced concrete (FRC) is the deceleration of crack growth and hence it’s improved sustainability due to e.g. decrease of permeability of concrete by aggressive substances. Additional benefits are associated with the structural properties of FRC, where fibres can significantly increase the ductility and the tensile strength of concrete. In some applications, such as tunnel linings or industrial slabs, it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits. Fibre reinforcement can, however, have critical disadvantages and even hinder the performance of concrete, since it can induce an anisotropic material behaviour of the mixture if the fibres are not appropriately oriented. For a safe use of FRC in the future, reliable non-destructive methods need to be identified to assess the fibres’ orientation in hardened concrete. In this study, ultrasonic material testing, electrical impedance testing, and X-ray computer tomography have been investigated for this purpose using specially produced samples with biased or random fibre orientations. This paper demonstrates the capabilities of each of these NDT techniques for fibre orientation measurements and draws conclusions based on these results about the most promising areas for future research and development using these techniques.
T2 - fib2020 Shanghai
CY - Online meeting
DA - 22.11.2020
KW - Ultrasonic testing
KW - Steel fibre reinforced concrete (FRC)
KW - Fibre orientation
KW - X-ray computed tomography (CT)
KW - Electrical impedance
PY - 2020
AN - OPUS4-51651
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Focused ion beam techniques beyond the ordinary - Methodological developments within ADVENT
N2 - This poster presents the focused ion beam preparation methodologies developed within the framework of the EU funded EURAMET project ADVENT (Advanced Energy-Saving Technology).
It summarises the key breakthroughs achieved for various in situ investigation techniques, e.g. in situ experiments at the Synchrotron facility BESSY II (IR-SNOM and XRS), TEM and SMM instrumentation.
The created experimental devices from diverse thin-film semiconductor materials paved the way to dynamic structural studies bearing the potential to determine nanoscale correlations between strain and electric fields and, moreover, for the fundamental development of new in situ capabilities.
N2 - Dieses Poster zeigt die FIB Präparationstechniquen, die im Rahmen des EU-finanzierten EURAMET-Projekts ADVENT (Advanced Energy Saving Technology) entwickelt wurden.
Es fasst die wichtigsten Errungenschaften zusammen, die für verschiedene in situ Untersuchungstechniken erzielt wurden, z.B. situ-Experimente in dem Synchrotronring BESSY II (IR-SNOM und XRS), in situ TEM Experimente und für die SMM Technik.
Die experimentellen Probenstrukturen, die aus verschiedenen Dünnschicht-Halbleitermaterialien erzeugt wurden, ebneten den Weg für dynamische Strukturstudien, die das Potenzial haben, nanoskalige Korrelationen zwischen Dehnung und elektrischen Feldern zu bestimmen und darüber hinaus neue in situ Messmethoden zu entwickeln.
T2 - Final Meeting
CY - Online Meeting
DA - 30.06.2020
KW - FIB
KW - Sample preparation
KW - In situ
KW - TEM
KW - AFM
PY - 2020
AN - OPUS4-51606
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Innovations- Plattform Material Digital
N2 - Mit der Initiative MaterialDigital fördert das BMBF seit dem letzten Jahr ein wichtiges Instrument zur Digitalisierung der Materialwissenschaft und Werkstofftechnik in Deutschland. In der ersten Phase dieser Initiative wird seit Juli 2019 die Plattform MaterialDigital von einem Konsortium aufgestellt. Ziel dieser Plattform ist der Aufbau eines virtuellen Materialdatenraums, um zusammen mit allen Interessenten die Systematisierung des Umgangs mit Werkstoffdaten voranzutreiben. In einer zweiten Phase werden akademische F&E-Projekte voraussichtlich Anfang 2021 gefördert. In jedem dieser Projekte wird an einer konkreten Fragestellung das Themenfeld „Digitalisierung der Materialwissenschaft und Werkstofftechnik“ adressiert und multidisziplinär bearbeitet. In einer dritten Phase werden im Rahmen industriegeführter vorwettbewerblicher Verbundprojekte mit der gleichen Zielsetzung gefördert.
T2 - Workshop - “Datenmanagement in der Additiven Fertigung”
CY - Online meeting
DA - 27.10.2020
KW - Digitalisierung
KW - Plattform Material Digital
KW - Virtueller Materialdatenraum
KW - Vernetzung
KW - Ontologien
PY - 2020
AN - OPUS4-51609
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Reference Materials at BAM
N2 - A introduction into reference materials, the certification process and brief over current reference projects at BAM is given.
T2 - AK-Postdoc seminar
CY - BAM Berlin, Germany
DA - 02.02.2021
KW - Referenzmaterialien
KW - Reference material
KW - Homogeneity
KW - Stability
KW - Quality testing
KW - Analytic
KW - DNA
KW - Dosimetry
KW - Certification
PY - 2021
AN - OPUS4-52060
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Lauster, T.
A1 - Retsch, M.
T1 - Design of Multimodal Absorption in the Mid-IR: A Metal Dielectric Metal Approach
N2 - Specific control on the mid-infrared (mid-IR) Emission properties is attracting increasing attention for thermal camouflage and passive cooling applications. Metal−dielectric−metal (MDM) structures are well known to support strong magnetic polariton resonances in the optical and near-infrared range. We extend the current understanding of such an MDM structure by specifically designing Au disc arrays on top of ZnS−Au−Si substrates and pushing their resonances to the mid-IR regime. Therefore, we combine fabrication via lift-off photolithography with the finite element method and an inductance−capacitance model.
With this combination of techniques, we demonstrate that the magnetic polariton resonance of the first order strongly depends on the individual disc diameter. Furthermore, the fabrication of multiple discs within one unit cell allows a linear combination of the fundamental resonances to conceive broadband absorptance. Quite importantly, even in mixed resonator cases, the absorptance spectra can be fully described by a superposition of the individual disc properties. Our contribution provides rational guidance to deterministically design mid-IR emitting materials with specific narrow- or broadband properties.
KW - Mid-IR absorption
KW - Thermal emission
PY - 2021
DO - https://doi.org/10.1021/acsami.0c18160
VL - 13
IS - 1
SP - 1921
EP - 1929
PB - ACS Publications
AN - OPUS4-52070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maslyk, M.
A1 - Bach, S.
A1 - Li, W.
A1 - Shylin, S.
A1 - Panthöfer, M.
A1 - Barton, B.
A1 - Ksenofontov, V.
A1 - Xu, K.
A1 - Kolb, U.
A1 - Schmedt auf der Günne, J.
A1 - Tremel, W.
A1 - Meermann, Björn
T1 - Understanding the Stability and Recrystallization Behavior of Amorphous Zinc Phosphate
N2 - Zinc phosphate, an important pigment in phosphate conversion coatings, forms protective films on rubbing surfaces.
We have simulated the underlying reactions under shear by ball-milling zinc phosphate and monitored the reaction of hopeite (Zn3(PO4)2·4H2O) and the retarded recrystallization of the amorphous reaction product by powder X-ray diffraction (PXRD) and quantitative infrared (IR) spectroscopy. Abrasion of stainless steel was simulated by addition of pure 57Fe. The results provide insight into the chemistry of phosphate conversion coatings or during battery cycling of metal phosphates and give theoretical guidance for the preparation of amorphous phosphates. Thermal analysis revealed that the release of structural water is a key step during the reaction of hopeite under shear to ball-milled amorphous zinc phosphate. The back-reaction and associated recrystallization kinetics of amorphous zinc phosphate show a classical Langmuir behavior. Fe impurities inhibit the recrystallization of ball-milled amorphous zinc phosphate strongly. 57Fe Mössbauer spectroscopy and PXRD revealed that Fe is oxidized to Fe2+ and Fe3+ during ball-milling and incorporated locally at the tetrahedral and octahedral sites of the structure. Ball-milled amorphous zinc phosphate is metastable as γ-Zn3−xFex(PO4)2. EPR studies showed the incorporation of Fe3+ to be coupled with the formation of Zn2+ vacancies. The Fe3+ defect sites bind water because of their higher Pearson hardness (compared to Fe2+ and Zn2+), thereby reducing water mobility and inhibiting further reactions like the recrystallization to hopeite. Our findings reveal the amorphization mechanism of Zn3(PO4)2·4H2O in stainless steel ball mills at the atomic scale and highlight how the reactivity of amorphous products is affected by impurities associated with the processing method.
KW - Amorphous Zinc phosphate
PY - 2021
DO - https://doi.org/10.1021/acs.jpcc.0c09044
VL - 125
IS - 4
SP - 2636
EP - 2647
AN - OPUS4-52078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
T1 - Development of a standard series for ellipsometry
N2 - Ellipsometry is a powerful tool, which allows the investigation of material properties over a broad spectral range. Over the course of several years, the ellipsometry lab at BAM has become an accredited testing lab according to ISO/IEC 17025 laying bare the need of better methods for accuracy and traceability. Despite its wide range of application in both research and development as well as industry, there have been no generally accepted standards dealing with model validation and measurement uncertainties.
Based on the first German standard DIN 50989 – 1: 2018 Ellipsometry - Part 1: Principles (currently international standard ISO 23131: 2021) and under consideration of GUM [1] a series of standards for ellipsometry was developed. The entire 6-part series covers several model-based application cases. This standards series avoids having narrow and material specific application cases but instead classifies applications of ellipsometry according to the sample complexity. The concept of ellipsometric transfer quantities (Ψ and Δ or alternatively the elements of transfer matrices) is implemented in the series. For each application case a model-based validation strategy was developed. Thus, the standards are applicable to all materials, instruments and measuring principles.
The uniform structure concept of the series facilitates its practical applicability for users. The standards include the model-based GUM-compliant determination/estimation of the measurement uncertainties. In addition, the appendices of the documents contain numerous measurement and simulation examples as well as recommendations for measuring practice.
In this contribution we present the application cases and basic structure of the standards developed in collaboration with Accurion GmbH and SENTECH Instruments GmbH in the project SNELLIUS.
T2 - 11th Workshop Ellipsometry (WSE 11)
CY - Steyr, Austria
DA - 06.09.2021
KW - Standardization of ellipsometry
KW - DIN 50989 Parts 1 – 6
KW - ISO 23131: 2021
KW - Validation concepts of ellipsometric measurements
KW - Uncertainty budgets
KW - GUM-compliance
PY - 2021
AN - OPUS4-53250
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 51, Heft 3
T3 - Amts- und Mitteilungsblatt der BAM - 3/2021
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
KW - Festlegungen
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533350
SN - 0340-7551
VL - 51
IS - 3
SP - 111
EP - 134
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-53335
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Lei
A1 - Hoyt, J. J.
T1 - Layering misalignment and negative temperature dependence of interfacial free energy of B2-liquid interfaces in a glass forming system
N2 - From molecular dynamics simulations and the capillary fluctuation method, the solid-liquid interfacial free energy has been computed for the B2-liquid interface in the Cu-Zr system. Consistent with previous results for the FCC-liquid interface in Cu-Zr and Al-Sm but atypical of most alloys, was found to increase as the temperature is lowered. In addition, the temperature dependence was obtained for model Lennard-Jones B2-liquid alloys. In all cases the unusual temperature dependence of is correlated with an atomic structure of the interfacial region characterized by a misalignment of the number density peaks between solvents and solutes. In cases where the number density peaks are aligned, the typical temperature dependence is observed. The results are discussed in terms of the Gibbs theory of the thermodynamics of interfaces. It is proposed that the unique interfacial structure and the atypical temperature dependence of are hallmarks of an easy glass forming alloy.
KW - Atomistic simulations
KW - Interfacial free energy
KW - Layering misalignment
KW - Glass forming
PY - 2021
DO - https://doi.org/10.1016/j.actamat.2021.117259
SN - 1359-6454
VL - 219
SP - 117259
PB - Elsevier Ltd.
AN - OPUS4-53650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Bala, P.
A1 - Hourahine, B.
A1 - Trager-Cowan, C.
T1 - Kikuchi pattern simulations of backscattered and transmitted electrons
N2 - We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKDcan be affected by changes in the order of 10−3–10−2 if excess-deficiency
features are not considered in the theoreticalmodel underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer frombiases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model.
KW - Electron diffraction
KW - EBSD
KW - Kikuchi diffraction
KW - Pattern matching
PY - 2021
DO - https://doi.org/10.1111/jmi.13051
VL - 284
IS - 2
SP - 157
EP - 184
PB - Wiley Online Library
AN - OPUS4-53584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maisels, A.
A1 - Hiller, A.
A1 - Simon, Franz-Georg
T1 - Chemisches Recycling für Kunststoffe: Status und Perspektiven
N2 - Das mechanische Recycling von Kunststoffen ist seit Jahren großtechnisch etabliert, hat aber technische und ökonomische Grenzen. Durch Verfahren des chemischen Recyclings gelangt man zurück zu Monomeren oder den Rohstoffen, so dass am Ende wieder Neuware für alle Einsatzgebiete von Kunststoffen entsteht. Die Vielfalt von chemischen Recyclingverfahren ist groß. Die Kapazitäten der Anlagen sind heute noch gering und die Wirtschaftlichkeit wird stark vom Ölpreis beeinflusst.
Die Rentabilitätsgrenze liegt derzeit bei einem Preis zwischen 50 und 60 US-$ pro Barrel.
KW - Chemisches Recycling
KW - Oxyfuel-Verbrennung
KW - Pyrolyse
KW - Solvolyse
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535952
DO - https://doi.org/10.1002/cite.202100115
SN - 0009-286X
SN - 1522-2640
VL - 93
IS - 11
SP - 1742
EP - 1750
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-53595
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - The structure of amorphous calcium sulfate and its role in the nucleation pathway and final mesostructure of CaSO 4 phases
N2 - In recent years, we have come to appreciate the astounding intricacy of the formation process of minerals from ions in aqueous solutions. In this context, a number of studies have already revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of the different crystalline phases involves several steps including a common amorphous precursor. In this contribution a holistic view of the formation mechanism of gypsum and bassanite from solution will be presented.
In short, our in situ and time-resolved scattering data demonstrate that calcium sulfate precipitation starts with the formation and aggregation of well-defined sub-3 nm primary species. These species constitute building “bricks'' of an amorphous precursor phase. We characterised the “bricks” by combining information obtained at different length-scales accessible at the mesoscale (from small-angle scattering) and at the atomic-length-scale (wide-angle scattering and high-energy diffraction). From these scattering data we derived pair distribution functions of the clusters and restricted their external shapes and dimensions. This allowed us to propose a structure of the primary species and to explore their dynamic properties with unbiased MD simulations using polarizable force fields. The formation of the amorphous phase involves the aggregation of these small primary species into larger disordered aggregates exhibiting “brick-in-the-wall” structure. The actual crystallisation occurs by the restructuring and coalescence of the “bricks” into a given calcium sulfate phase depending on the thermodynamic conditions of the solution. Importantly, these rearrangement processes by no means continue until a (nearly-)perfect homogeneous single crystal is obtained. Instead they come to a stop or at least significantly slow down. Such a process thus yields a final imperfect mesocrystal, composed of smaller domains rather than a continuous crystal structure, within which the domains are separated by an amorphous calcium sulfate phase.
T2 - Goldschmidt Virtual 2021
CY - Online meeting
DA - 04.07.2021
KW - Amorphous calcium sulfate
KW - Scattering
KW - SAXS/WAXS
PY - 2021
UR - https://2021.goldschmidt.info/goldschmidt/2021/meetingapp.cgi/Paper/3847
AN - OPUS4-53621
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolbe, Matthias
T1 - Untersuchungen zur Explosivbearbeitung von Bauteilen in Schiffsmotoren
N2 - Vorstellung des Plattierens von Metallen mit Hilfe von Explosivstoffen.
T2 - 42. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 15.10.2021
KW - Explosivstoffe
KW - Sprengplattieren
KW - TTS
PY - 2021
AN - OPUS4-53632
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schridewahn, S.
A1 - Spranger, F.
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Laser Implantation of Niobium and Titanium-Based Particles on Hot Working Tool Surfaces for Improving the Tribological Performance within Hot Stamping
N2 - Within the scope of this work, a laser implantation process has been used, in order to improve the tribological performance of hot stamping tools. This surface engineering Technology enables the generation of dome-shaped, elevated and highly wear resistant microfeatures on tool surfaces in consequence of a localized dispersing of hard ceramic particles via pulsed laser radiation.
As a result, the topography and material properties of the tool and thus the tribological interactions at the blank-die interface are locally influenced. However, a suitable selection of hard ceramic particles is imperative for generating defect-free surface features with a high share of homogenously disturbed particles. For this purpose, different niobium (NbB2 and NbC) as well as titanium-based (TiB2 and TiC) materials were embedded on hot working tool specimens and subsequently analyzed with regard to their resulting shape and mechanical properties. Afterwards, modified pin-on-disk tests were carried out by using conventional and laser-implanted tool surfaces, in order to evaluate the wear and friction behavior of both tooling systems.
KW - Surface modification
KW - Triobology
KW - Laser implantation
PY - 2020
DO - https://doi.org/10.4028/www.scientific.net/DDF.404.117
SN - 1662-9507,
VL - 404
SP - 117
EP - 123
PB - Trans Tech Publications Ltd.
AN - OPUS4-53690
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schridewahn, S.
A1 - Spranger, F.
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Verbesserung des tribologischen Einsatzverhaltens von Presshärtewerkzeugen durch Laserimplantation titanbasierter Hartstoffpartikel
N2 - In der Automobilindustrie stellt das Presshärteverfahren eine Schlüsseltechnologie zur ressourceneffizienten Herstellung sicherheitsrelevanter Karosserie-komponenten dar. Während der Umformoperation treten jedoch hohe Reibungs- und Verschleißerscheinungen an den interagierenden Werkzeug- und Werkstückwirkflächen auf, die sowohl die Bauteilqualität als auch die Maschinenstandzeit nachhaltig beeinträchtigen. Um die bestehenden Verfahrensgrenzen zu erweitern, wird daher eine Modifikation der Presshärtewerkzeuge mittels Laserimplantation angestrebt. Hierbei werden in die Werkzeugoberfläche keramische Hartstoffpartikel anhand eines gepulsten Laserstrahles eingebettet, infolgedessen kuppelförmige sowie höchstfeste Strukturen im Mikrometerbereich entstehen. Die Auswahl geeigneter Hartstoffmaterialien stellt jedoch ein entscheidendes und bisweilen limitierendes Kriterium dar, um defektfreie sowie verschleißresistente Oberflächenmodifikationen zu generieren. In diesem Zusammenhang wurden im Rahmen dieser Arbeit unterschiedliche titanbasierte Hartstoffpartikel auf presshärtespezifische Werkzeugstähle laserimplantiert und anschließend mittels modifizierten Pin-on-Disk-Tests hinsichtlich ihres tribologischen Einsatzverhaltens untersucht. Um die Wirksamkeit des Laserimplantationsverfahrens zu evaluieren, wurden zudem Verschleißuntersuchungen an unmodifizierten Werkzeugoberflächen durchgeführt und mit den erzielten Ergebnissen der lokal dispergierten Topographien verglichen.
T2 - 15. Erlanger Workshop Warmblechumformung 2020
CY - Erlangen, Germany
DA - 17.11.2020
KW - Laserimplantation
KW - Werkzeugmodifikation
KW - Presshärten
KW - Tribologie
PY - 2020
SP - 1
AN - OPUS4-53692
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sachse, René
T1 - Towards hydrogen economy: correlative ex-situ ellipsometric analysis and operando investigation during oxygen evolution reaction of mesoporous iridium oxides films
N2 - In the face of rising energy demand and the impending climate change the development of a sustainable, fossil-free fuel and chemical production is of global importance. One possible goal is the development of electrochemical conversion processes using catalysts. Porous materials play an important role in such energy applications. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physico-chemical properties. However, the complex morphology of such catalysts constitutes a challenge even for modern analytical techniques.
Spectroscopic ellipsometry (SE) is a versatile method for studying material properties by using appropriate models (e.g. film thickness, optical and electronic properties). The fact that the material properties cannot be taken directly from the measured spectra, the developed models have to be validated. In a first step, the model for the ellipsometric fit studies of a calcination series of mesoporous iridium oxide films (300 – 600 °C) was investigated and validated with respect to their material properties. Moreover, the electronic structures of the catalysts reveal a direct correlation with electrochemical activities. The development of an environmental cell offers the possibility of investigations under real conditions. This will allow changes in the optical and electronic properties during the electrocatalytic oxygen evolution reaction.
T2 - Colloquium Department Seminar 6.
CY - BAM, Berlin, Germany
DA - 03.03.2020
KW - Hydrogen economy
KW - Correlative ex-situ ellipsometric analysis
KW - Ellipsometric operando investigation
KW - Oxygen evolution reaction
KW - Mesoporous iridium oxides films
PY - 2020
AN - OPUS4-51215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Colini, Claudia
ED - Michel, C.
ED - Friedrich, M.
T1 - La invencíon del Sacromonte: How and Why Scholars Debated about the Lead Books of Granada for Two Hundred Years
N2 - At the end of the sixteenth century, a number of relics and artefacts were discovered in Granada, Spain. They included what became known as the Lead Books of the Sacromonte, twenty-one written artefacts made of circular lead leaves engraved in archaic Arabic characters. The authorship was attributed to some Arab disciples of St James the Greater considered to be the first evangelisers of the Iberian Peninsula. The texts, the materiality and the circumstances of the discoveries fuelled a debate surrounding their authenticity that lasted more than two centuries, a debate so fierce and controversial that not even papal condemnation in 1682 was able to stop it. Soon after the discoveries were made public, scholars highlighted the many contradictions and errors of a historical, linguistic and theological nature present in the texts, identifying members of the local Morisco community as possible forgers. This article focuses on how the scholarly community of the sixteenth and seventeenth centuries handled these findings and looks at the methods employed by the scholars to evaluate the authenticity of the artefacts. It will also look at how the particular interests of the various authorities involved influenced the acceptance or dismissal of relevant academic results.
KW - Forgery
KW - Moriscos
KW - Parchment
KW - Lead books
PY - 2020
UR - https://www.degruyter.com/view/title/590832
DO - https://doi.org/10.1515/9783110714333-011
VL - Studies in Manuscript Cultures 20
SP - 209
EP - 262
PB - De Gruyter
CY - Berlin/Boston
AN - OPUS4-51936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Charmi, Amir
T1 - Mechanical anisotropy of additively manufactured stainless steel 316l: an experimental and numerical study
N2 - This work aims for a yield function description of additively manufactured (AM) parts of stainless steel 316L at the continuum-mechanical macro-scale by means of so-called virtual experiments using a crystal plasticity model at meso-scale.
T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - BAM, Berlin
DA - 10.12.2020
KW - Anisotropy
KW - Crystal plasticity
KW - Additive manufacturing
PY - 2020
AN - OPUS4-51941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte, Larissa
A1 - Andrade, Ana Carolina
A1 - Bettge, Dirk
T1 - Fractographic Analysis of Fatigue Striations Formation under different Microstructures and Loading Conditions
T1 - Fraktographische Untersuchung der Bildung von Schwingstreifen bei
unterschiedlichen Gefügezuständen und Belastungsbedingungen
N2 - Fatigue failure of a component can occur at service loads considerably lower than the yield strength of the material. Under fatigue loading condition, the material in the vicinity of the tip of a propagating crack repeatedly deforms plastically, leaving microscopic marks on the crack surface, commonly known as fatigue striations. Counting and measuring fatigue striations is a method in estimating the number of loading cycles a component went through until fracture. Some studies suggest a one-to-one relation between the number of fatigue striations and the number of load cycles, but this relation is still debatable, given that there are many factors influencing the formation of those striations. The main purpose of this work is to analyze the influence of microstructure and mechanical strength on the formation of fatigue striations in structural steels, in order to understand how these material properties are related to the fatigue crack behavior. For such, standard Charpy-V samples were subjected to hardness, fatigue and impact testing. Metallography was performed to characterize the microstructure, and a fractographic analysis by using optical and scanning electron microscopy was carried out to investigate the fracture surface. This study shows that steels with higher ductility have a closer one-to-one relation than those with a higher tensile strength. Above a certain level of tensile strength, fatigue striations do form rarely or completely disappear.
N2 - Weit unterhalb der Streckfestigkeit des Werkstoffs kann es durch Schwingbruch zum Bauteilversagen kommen. Unter Schwingbeanspruchung
wird der Werkstoff in der Nähe der Spitze eines sich ausbreitenden Risses wiederholt plastisch verformt. Dabei entstehen allgemein als Schwingstreifen bekannte mikroskopische Spuren. Das Zählen und Vermessen von Schwingstreifen ist ein Verfahren zum Schätzen der Anzahl von Belastungszyklen, denen ein Bauteil bis zum Bruch ausgesetzt war. Einige Studien legen hier eine 1 : 1-Beziehung
zwischen der Anzahl von Schwingstreifen und der Anzahl von Lastspielen nahe.
Dies erscheint angesichts der zahlreichen, die Bildung solcher Streifen beeinflussenden Faktoren allerdings fraglich. Hauptziel dieser Arbeit ist die Untersuchung der Auswirkungen des Gefüges und der mechanischen Festigkeit auf die Bildung von Schwingstreifen in
Baustählen, um Zusammenhänge zwischen diesen Werkstoffeigenschaften und dem Schwingbruchverhalten verstehen zu können.
Dafür wurden an Standard-Charpy-V-Proben Härte- sowie Schwing- und Schlagprüfungen durchgeführt. Zur Gefügecharakterisierung wurden die Proben metallographisch untersucht.
Die Bruchfläche wurde zur Analyse fraktographisch licht- und rasterelektronenmikroskopisch untersucht. Die vorliegende Untersuchung zeigt dabei auf, dass Stähle mit einer höheren Duktilität näher an eine solche 1 : 1-Beziehung herankommen als solche mit einer höheren Zugfestigkeit. Oberhalb einer bestimmten Zugfestigkeit bilden sich selten oder gar keine Schwingstreifen.
KW - Schwingstreifen
KW - Fatigue striations
PY - 2020
DO - https://doi.org/10.3139/147.110668
VL - 57
IS - 12
SP - 869
EP - 886
PB - Carl Hanser Verlag
CY - München
AN - OPUS4-51952
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
A1 - Fontana, P.
A1 - Hoppe, Johannes
A1 - Bilgin, S.
A1 - Meng, Birgit
ED - Serrat, C.
ED - Casas, J. R.
ED - Gibert, V.
T1 - Composite Facade Elements with Self-Cleaning Surface made of Ultra-High-Performance Concrete (UHPC)
N2 - In the framework of the European project H-House various concrete façade elements were developed with the aim to ensure a long service life by combining a very durable material with self-cleaning properties. The façade elements presented are made of a shell of UHPC filled with blocks of aerated autoclaved concrete as insulating material. Self-cleaning properties were realized amongst others by imprinting a microstructure into the surface during casting. The paper focuses on selected technological aspects of the manufacturing process of prototypes which had to be performed in two concreting sections. Furthermore the challenges faced when upscaling the self-cleaning properties are addressed and the strategy to assess the self-cleaning properties by measuring the contact and the roll-off angel is presented. The results show that a successfull upscalaing process requires detailed planning and that the best results can often be achieved with a moderate work effort or material use.
T2 - XV International Conference on Durability of Building Materials and Components (DBMC 2020)
CY - Online meeting
DA - 20.10.2020
KW - Ultra-High-Performance Concrete
KW - Facade Elements
KW - Self-Cleaning Properties
KW - Adhesive Pull-Strength
KW - Microstructure
KW - Architectural Concrete
PY - 2020
SN - 978-84-121101-8-0
SP - 1289
EP - 1297
PB - International Center for Numerical Methods in Engineering (CIMNE)
CY - Spain
AN - OPUS4-51967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spaltmann, Dirk
T1 - Trusted Qualification - On the need for procedures to harmonize tribological testing
N2 - In order to shorten time to market of products and to support new developments, the European Community is funding a HORIZON 2020 project called i-TRIBOMAT. In the field of tribology, renowned institutions combine their testing and analytical capabilities to provide the respective services. The later will be offered in Europe via a Single-Entry Point (SEP). Due to this combination of services, a testbed is created consisting of more than 100 tribometers. Thus, a large variety of testers exists, either commercially available or in-house built. Each tester is optimised to simulate a specific tribological contact situation. Currently, there is no standard available for the design of such testers. Especially, the way forces (normal load, friction force) and distances (e.g. stroke, linear wear) are measured, recorded and pre-processed differs from type to type. These forces and distances are essential for the determination of wear/ wear rates and coefficients of friction (COF), the core results of tribo-tests. This matter is complicated by the fact that e.g. for reciprocating motion, there are at least four different ways to determine COF. Depending on the testing conditions, these ways can lead to considerably different results. Currently, it is not obligatory to specify the method used for determining the COF.
In order to make data comparable, there is a need for measures which ensure that each tribometer is delivering similar, at best the same results under the same test conditions, irrespective of its manufacturer, design, location, determination method and even operator. The way forward are improved Round-Robin tests. First results and other challenges faced by creating comparable tribological data will be considered in the present contribution.
T2 - LUBMAT 2020
CY - Online meeting
DA - 15.12.2020
KW - I-TRIBOMAT
KW - Tribo-tests
KW - Tribological data
PY - 2020
AN - OPUS4-51981
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bulling, Jannis
A1 - Franosch, Georg
A1 - Lugovtsova, Yevgeniya
A1 - Prager, Jens
ED - Rizzo, P.
ED - Milazzo, A.
T1 - Sensitivity of Ultrasonic Guided Waves to Elastic Constants: A Numerical Study
N2 - The dispersive properties of Lamb waves can be utilised for material characterisation because the frequency-wavenumber-relationship, as well as the group velocity, depend on material parameters. These dependencies make a non-destructive estimation of an elastic constant possible. This preliminary study investigates the sensitivity of dispersion curves caused by a change in elastic constants. The Scaled Boundary Finite Element Method is used to compute special dispersion curves, which show the sensitivity value of the frequency and group velocity as a colour value. This representation allows for easy identification of patterns and local effects. Two sets of dispersion curves are presented, one set for a steel plate and the other set for a plate made of a carbon fibre reinforced polymer. In general, we notice that the sensitivity often increases with the frequency and that higher-order modes seem to be more suitable for material characterisation. Moreover, specific modes respond to material changes while others are relatively unaffected, which must be taken into consideration for material characterisation.
T2 - European Workshop on Structural Health Monitoring (EWSHM 2020)
CY - Online meeting
DA - 06.07.2020
KW - Scaled Boundary Finite Element Method
KW - Lamb waves
KW - Dispersion curves
KW - Carbon fibre reinforced polymer
KW - Transverse isotropy
PY - 2021
SN - 978-3-030-64593-9
DO - https://doi.org/10.1007/978-3-030-64594-6_73
VL - 127
SP - 759
EP - 768
PB - Springer
CY - Cham
AN - OPUS4-51986
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Uncertainty budgets in surface technology: stepheigt, layerthickness, indentation hardness, adehesive strength
N2 - The object (sample) and the measurement/testing procedure may always have unknown degrees of freedom, i.e. instead of 𝐯 ≥ n – 1 in many cases 𝐯 ≫ n - 1 may apply, in particular in the micro- and nano-world!
T2 - 10. VDI-Fachtagung, Messunsicherheit und Prüfprozesse
CY - Erfurt, Germany
DA - 10.11.2021
KW - Methodology in metrology
KW - Methodology in testing
KW - Spectroscopic Ellipsometry
KW - Instrumented Indentation Testing (IIT)
KW - Centrifugal Adhesion Testing (CAT)
PY - 2021
AN - OPUS4-53986
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Functional coatings for mechanical applications: characterization and standardization
N2 - The paper addresses the “Functional coatings for mechanical applications: characterization and standardization” and the following points are discussed in more detail:
1. Mechanic alapplications (coatings for tools and components, system features vs. material parameters)
2. Mechanical characterization (instrumented indentation testing (IIT), centrifugal adhesion testing (CAT), state of standardization)
3. Topometric characterization (white light interference microscopy (WLIM, 3D), mechanical stylus (MS, 2D), state of standardization)
4. Optical characterization (spectroscopic ellipsometry (SE), inter-laboratory comparison, state of standardization)
T2 - IC-CMTP6
CY - Miskolc, Hungary
DA - 04.10.2021
KW - Spectroscopic Ellipsometry
KW - White Light Interference Microscopy
KW - Instrumented Indentation Testing
KW - Functional coatings
KW - Mechanical characterization
KW - Optical characterization
KW - Topometric characterization
KW - Standardization
PY - 2021
AN - OPUS4-53987
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reetz, U.
T1 - Load- and path-controlled determination of bonding strength of butt joints - Comparison between tensile testing machine and centrifuge technology
N2 - The round robin test proves that the CAT-Technology provides statistically indistinguishable test results compared to TTM. A supplement to DIN EN 15870 taking into account CAT-Technology (with reference to equivalent increases of load and displacement) as second normative test method appears to make sense.
A presentation of a revision proposal at CEN TC 193 has been introduced with the decision to conduct a survey using the unchanged German revision proposal.
T2 - EURADH 2021 - 13 th European Adhesion Conference
CY - Online meeting
DA - 11.10.2021
KW - CAT – Technology
KW - Tensile testing machine (TTM)
KW - Round robin test
KW - Validation
PY - 2021
AN - OPUS4-53948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Katsikini, M.
A1 - Filintoglou, K.
A1 - Pinakidou, F.
A1 - Pilatsikas, N.
A1 - Arvanitidis, J.
A1 - Christofilos, D.
A1 - Paloura, E.C.
A1 - Ves, S.
A1 - Reinholz, Uwe
A1 - Papadomanolaki, E.
A1 - Lliopoulos, E.
T1 - Scaling of phonon frequencies and electron binding energies with interatomic distances in InxGa1−xN
N2 - In-K-edge x-ray absorption fine structure (EXAFS), x-ray photoelectron, and Raman spectroscopy results are combined for a comprehensive study of InxGa1−xN layers with energy gaps extending over nearly the whole visible spectrum. The In–N and In–(In,Ga) distances determind by EXAFS are used for the derivation of the In–N bond ionicity as well as for the phonon frequency dependence of the LO and B21 modes, assessed by Raman, and the N 1s, In 3d5/2, Ga 3s, and Ga 2p1/2 electron binding energies on those distances. Phonon confinement due to perturbation of the periodic potential caused by the alloying is also quantified.
KW - Band gap
KW - Phonons
KW - Epitaxy
KW - Electronic structure
KW - X-ray photoelectron
KW - Nitrides
PY - 2021
DO - https://doi.org/10.1063/5.0069359
VL - 130
IS - 20
SP - 205706 - 1
EP - 205706 - 9
PB - AIP Publishing
AN - OPUS4-53956
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Joubert, J.M.
A1 - Crivello, J.C.
A1 - Yusenko, Kirill
T1 - Modification of Lu's (2005) high pressure model for improved high pressure/high temperature extrapolations. Part II: Modeling of osmium-platinum system at high pressure/high temperature
N2 - In Part I of this paper, we have described a modification brought to the model of Lu (X.-G. Lu et al., Comput. Coupling Phase Diagr. Thermochem. 29 (2005) 49–55) in order to avoid extrapolation problems at high pressure and temperature. We now extend this approach to the study of a binary system: Os–Pt. For this, a complete description (equation of state) of Os at high pressure/high temperature is provided including the liquid phase. The thermodynamic assessment of the system Os–Pt has been carried out at ambient pressure by the Calphad method. All this study has been supported by first principles, special quasi-random structure (including under high pressure) and phonon calculations. Finally, using the high pressure description of metastable structures (hcp Pt and fcc Os), we have been able to obtain by extrapolation a complete description of Os–Pt system up to 500 GPa. Recent experimental data for Os–Pt system obtained up to 50 GPa at various temperatures up to 2300 °C may us allow to validate our modeling approach.
KW - Phase diagrams
KW - High-pressure
PY - 2021
DO - https://doi.org/10.1016/j.calphad.2021.102311
VL - 74
SP - 102311
PB - Elsevier
AN - OPUS4-54005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fedorova, E.A.
A1 - Asanov, Igor
A1 - Yusenko, Kirill
A1 - Asanova, T.I.
A1 - La Fontaine, Camille
A1 - Roudenko, olga
A1 - Gerasimov, E.Y.
A1 - Vasilchenko, D
A1 - Korenev, S.V.
T1 - Time-resolved study of thermal decomposition process of (NH4)(2) PtCl6 : Intermediates and Pt nucleation
N2 - Evolution in crystal, electronic and local atomic structures of Pt in ammonium hexachloroplatinate in the course of thermal decomposition in inert and reducing atmospheres have been studied by Powder X-Ray Diffraction (PXRD) and Quick X-ray Absorption Fine Structure (QXAFS) at Pt L3-edge for deeper understanding the thermally-induced solid state reaction and the formation of metallic nanoparticles. A three-step thermal decomposition mechanism of (NH4)2[PtCl6] in the inert atmosphere with the intermediate products Pt(NH3)2Cl2 and PtCl2 has been found instead one-[G.Meyer, A.Möller, J. Less. Common. Met. 170 (1991) 327–331] and two-step one [Q.Kong, F.Baudelet, J.Han, S.Chagnot, L.Barthe, J.Headspith, R. Goldsbrough, F.E.Picca, O.Spalla, Sci. Rep. 2 (2012) 1018–1025] considered early. In the reducing atmosphere, the thermal decomposition is a two-step process with the formation of the intermediate PtCl2. The best approach to determining the number of thermal decomposition steps turned out to be the express-analysis of QXAFS spectra offered in the papers, based on the simultaneous presentation of the most important parameters extracted from X-ray Absorption Near Edge Structure (XANES) and Fourier transformed Extended XAFS (EXAFS). This express-analysis was tested by comparison with results of various approaches such as conventional EXAFS fitting, linear combination fit (LCF), Multivariate Curve Resolution Alternating Least Squares method (MCR ALS).
KW - Platinum
KW - Quick-EXAFS
PY - 2021
DO - https://doi.org/10.1016/j.vacuum.2021.110590
VL - 194
SP - 110590
PB - Elsevier
AN - OPUS4-54008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asanova, T.I.
A1 - Asanov, Igor
A1 - Yusenko, Kirill
A1 - Le Fontane, Camille
A1 - Gerasimov, E.Y.
A1 - Zadesenetz, A.V.
A1 - Korenev, S.V.
T1 - Time-resolved study of Pd-Os and Pt-Os nanoalloys formation through thermal decomposition of Pd(NH3)(4) OsCl6 and Pt(NH3)(4) OsCl6 complex salts
N2 - The formation mechanisms of Pd-Os and Pt-Os alloys in the course of thermal decomposition of iso-formular and isostructural complex salts [Pd(NH3)4][OsCl6] and [Pt(NH3)4][OsCl6] in an inert atmosphere have been studied by in-situ QXAFS, XPS and PXRD. The mechanisms of thermal decomposition of the precursors are found to differ from each other, but the detected intermediate products show no significant effect on the local atomic structure around Os, Pt/Pd in their final products. A crystalline beta-trans-[Pd(NH3)2Cl2] intermediate of the first step of thermal decomposition of [Pd(NH3)4][OsCl6] makes the anion [OsCl6]2− transform differently than that of [Pt(NH3)4][OsCl6]. It transforms into a short-lived [Os(NH3)xCl6-x] (2≤x≤4), and then to a distorted octahedron [OsCl6]2−, similar to the high-temperature modification of OsCl4. In case of [Pt(NH3)4][OsCl6], the intermediate [Os(NH3)2Cl4] modifies into four chlorine coordinated Os,{OsCl4}0/1−. Consecutive reduction of Pd(II)/Pt(II) and Os(IV) to the metals defines the homophilic atomic order with the fcc-Pd covered by a random Pd-Os alloy layer and Os on the surface, that is supported by High-Resolution Transmission Electron Mictroscopy (HRTEM) and Scanning TEM (STEM) energy dispersive X-ray (EDX) data, and the diffusion direction going from the surface (hcp-Os) to bulk (fcc-Pd/Pt). As a result, the heterogeneous alloys are formed with a very similar electronic and local atomic structure of Os and Pd/Pt. Upon alloying, the Os 5d5/2,3/2 and Pt 5d5/2,3/2 levels are depleted in the Pt-Os alloys compared to dispersed hcp-Os, fcc-Pt, and Pt foil. This is an unusual behaviour for Os and Pt, calling into question the versatility of d-band theory in bimetallic Os-alloys. The spin-orbit effect at the Os site has been found for both the Pd-Os and Pt-Os alloys, but it is about 4 times less compared to the complex salts. The obtained values for the complex compounds are comparable with those for the iridates, proposed as materials with spin-orbit-induced properties.
KW - Thermal decomposition
KW - Quick-EXAFS
PY - 2021
DO - https://doi.org/10.1016/j.materresbull.2021.111511
VL - 144
SP - 111511
PB - Elsevier Ltd.
AN - OPUS4-54010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serebrennikova, P.
A1 - Komarov, V.
A1 - Sukhikh, A.
A1 - Khranenko, S.
A1 - Zadesenetz, A.
A1 - Gromilov, S
A1 - Yusenko, Kirill
T1 - [NiEn3](MoO4)0.5(WO4)0.5 co-crystals as single-source precursors for ternary refractory Ni-Mo-W alloys
N2 - The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown.
KW - Single source precursors
KW - Phase diagrams
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540123
DO - https://doi.org/10.3390/nano11123272
VL - 11
IS - 12
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-54012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yusenko, Kirill
T1 - Single-source precursors strategy to access refractory high-entropy alloys for electrocatalytic applications
N2 - High-entropy alloys containing up to 6 platinum group metals can be prepared by thermal decomposition of single-source precursors non requiring high temperature. We prepare the first example of a single-phase hexagonal high-entropy alloy. Heat treat- ment up to 1500 K and compression up to 45 GPa do not result in phase changes, a record temperature and pres- sure stability for a single-phase high-entropy alloy. The alloys show pronounced electrocatalytic activity in methanol oxidation, which opens a route for the use of high-entropy alloys as materials for sustainable energy conversion.
T2 - HEA2020: first international virtual workshop on high-entropy alloy and complex solid solution nanoparticles for electrocatalysis
CY - Online meeting
DA - 06.10.2020
KW - High-entropy alloys
KW - Single-source precursors
PY - 2020
AN - OPUS4-54013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yusenko, Kirill
A1 - Smekhova, A.
A1 - Kuzmin, A.
T1 - Extended X-Ray absorption fine structure (exafs) to study local constitution of high-entropy alloys
N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision.
T2 - SPP2006: ordering in high-entropy alloys
CY - Online meeting
DA - 05.10.2021
KW - EXAFS
KW - High-entropy alloys
PY - 2021
AN - OPUS4-54015
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
T1 - Prozesssimulation elektromagnetischer Kräfte zum Fügen artungleicher Werkstoffe
N2 - Prozesssimulation zur Eingrenzung der elektromagnetischen Kräfte zum gezielten Verdrängen einer laserstrahlinduzierten Schmelze zum Fügen artungleicher Materialien. Berechnung der Lorentzkraftverteilung im Schmelzbad. Abschätzung der Temperaturentwicklung beim Verdrängungsprozess.
T2 - Assistentenseminar der WGF 2020
CY - Online meeting
DA - 01.09.2020
KW - Stahl und Aluminium
KW - Artungleiche Werkstoffe
KW - Elektromagnetische Schmelzbadbeeinflussung
KW - Fügetechnologie
KW - Laserstrahlschweißen
PY - 2020
SN - 978-3-96144-141-9
VL - 370
SP - 51
EP - 60
PB - DVS Media GmbH
AN - OPUS4-53927
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grzegorz, Nehring
A1 - Krutzsch, M.
A1 - Rabin, Ira
T1 - Tuschenanalyse im P 11702
T1 - Ink Analysis in P 11702
N2 - Near-inframed reflectography and imaging X-Ray flourescence analysis reveal that carbon inks of two different compositions were used in the papyrus manuscript Berlin P 11702. in contrast with the writing ink, one of the carbon drawing inks contained a significant addition of iron. This result emphasises the need for routine instrumental ink analysis.
KW - Papyrus
KW - Ink analysis
KW - X-Ray flourescence spectroscopy
KW - Near-infrared refelctography
PY - 2021
DO - https://doi.org/10.1515/apf-2021-0026
SN - 1867-1551
VL - 67
IS - 2
SP - 277
EP - 282
PB - De Gruyter
AN - OPUS4-53942
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wilrich, Cordula
T1 - Sicherheitsdatenblatt: Physikalisch-chemische Eigenschaften im Abschnitt 9
N2 - Daten und Informationen zu physikalisch-chemischen Eigenschaften und Gefahren von Stoffen und Gemischen sind im Sicherheitsdatenblatt in Abschnitt 9 anzugeben. Die Anforderungen stammen aus REACH Anhang II und sind Anfang 2021 neugefasst worden. REACH implementiert damit die Neufassung des entsprechenden Abschnitts 9 aus dem UN-GHS – mit einigen europäischen Ergänzungen.
Der Vortrag gibt einen Überblick über die Änderungen und stellt die Ergänzungen, die sich an die Ersteller von Sicherheitsdatenblättern richten, anhand einiger aussagekräftiger Beispiele vor.
T2 - Informationsveranstaltung „REACH: Aktuelles zum Sicherheitsdatenblatt - Wie, was, wann?“ der nationalen Auskunftsstelle des Bundes für REACH, CLP und Biozide (Helpdesk)
CY - Online meeting
DA - 02.12.2021
KW - Chemikalienrecht
KW - Gefahrstoffe
KW - GHS
KW - Physikalische-chemische Eigenschaften
KW - Physikalische Gefahren
KW - REACH
KW - SDS
KW - Sicherheitsdatenblatt
PY - 2021
UR - https://www.reach-clp-biozid-helpdesk.de/SharedDocs/Termine/DE/2021-12-02_Aktuelles_zum_Sicherheitsdatenblatt.html
AN - OPUS4-53913
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reetz, U.
T1 - CAT -Technologie (CentrifugalAdhesionTesting) im Standardisierungsprozess
N2 - Der DIN Ringversuch weist nach, dass die CAT Technologie zur ZPM Prüfung statistisch nicht unterscheidbare Prüfergebnisse liefert, so dass lediglich eine Ergänzung der DIN EN 15870 unter Berücksichtigung der CAT-Technologie (mit Bezug auf äquivalente Kraft und Weg zunahmen) als zweiter normativer Prüfmethode sinnvoll erscheint.
Vorstellung des Revisionsvorschlages im CEN TC 193 am 08.04.2021 mit dem Beschluss, eine Umfrage unter Verwendung des unveränderten deutschen Revisionsvorschlages durchzuführen.
T2 - SKZ-Expertenkreis „Kleben und Oberflächentechnik für Kunststoffe“ 2021
CY - Online meeting
DA - 22.09.2021
KW - Centrifugal Adhesion Testing (CAT)
KW - Zweistichproben t Test: (ZPM)
KW - Ringversuch
KW - Validierung
KW - DIN EN 15870
PY - 2021
AN - OPUS4-53964
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kalinka, Gerhard
T1 - Optische Beobachtungen der Faser-Matrix-Trennung im Pull-out-Versuch
N2 - Der Vortrag behandelt Rissentstehung und Ausbreitung an Faser-Matrix-Interfaces, untersucht mit dem optischen Mikroskop.
T2 - Composites United, CU-Arbeitsgruppe/n Faser-Matrix-Haftung & Matrices
CY - Online meeting
DA - 02.12.2021
KW - Faser
KW - Matrix
KW - Pull-out
KW - Interface
PY - 2021
AN - OPUS4-53968
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lagleder, Michaela
T1 - Materialographische Untersuchungen an Bauteilen
N2 - Eine Grundanforderung an Bauteile ist deren mechanische Integrität, die als Festigkeit (globale Bauteilbeanspruchung) bzw. Tragfestigkeit (lokale Beanspruchung) zu verstehen ist. Die Bauteilfestigkeit wird wesentlich durch das Materialgefüge bestimmt und kann über die Prüfung der Härte des Grundwerkstoffes lokal erfasst werden. Bei Bauteilverbindungen (z.B. Schweißnähte) ist zudem der Übergangsbereich zwischen den Fügeteilen von besonderem Interesse, bei Passungen oder Gleitlagern sind zudem geringe Rauheiten erforderlich, die oft durch mechanische Oberflächen-bearbeitung realisiert werden. Leichtbauweisen können sowohl über hochfeste Stahllegierungen bei geringem Materialeinsatz als auch über Aluminiumlegierungen realisiert werden. Für unterschied-liche Grundwerkstoffe (X2CrNiMo18-14-3, Co-Cr-W-Ni, AlSi10Mg, X5CrNi1810, ferritische Schweiß-nähte) werden an Quer- und Oberflächenschliffen Änderungen im Gefüge, morphologische Besonderheiten, Härteverläufe sowie Änderungen in den Rauheitskennwerten betrachtet, wie sie im Ergebnis mechanischer Oberflächenbearbeitung, bedingt durch den Herstellungsprozess, die Beanspruchung oder den Fügeprozess auftreten. Zur Validierung der Härtebestimmung wurde ein Laborvergleichsversuch an einer MPA-zertifizierten Härtevergleichsplatte und einer 100Cr6 Referenzprobe durchgeführt, den drei bzw. fünf der insgesamt fünf Teilnehmer bestanden.
T2 - 55. Materialographie-Tagung
CY - Online meeting
DA - 29.09.2021
KW - Gleitlinien
KW - Rauheit
KW - Härteverlauf Schweißnaht
KW - Laborvergleich Härte
KW - Aluminium
PY - 2021
AN - OPUS4-53503
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Netzband, Olivia
T1 - Materialographische Untersuchungen an Funktionsschichten
N2 - Oberflächenmodifizierte Grundwerkstoffe, insbesondere solche mit funktionellen Schichten, sind in unterschiedlichsten Branchen und Anwendungen anzutreffen. Es werden Quer- und Kalottenschliffe von Einfach- und Mehrschichtsystemen mit Beispielen aus dem Bereich des Korrosions- und Verschleißschutzes sowie dekorativer Anwendungen auf unterschiedlichsten Grundwerkstoffen (X5CrNi1810 Stahl, 100Cr6 Stahl, Hartmetall, ABS und Pappe) vorgestellt. Ebenso vielfältig wie die Grundwerkstoffe sind die Oberflächenmodifizierungen mit Funktionsschichten auf Basis von Nitrierungen, Hartstoffen, diamantähnlichem Kohlenstoff, Metallisierungen und Lackschichten mit Interferenzpigmenten. Neben der Identifikation von Schichtdefekten gilt das Hauptaugenmerk der materialographischen Analyse der Erfüllung der Schichtdickenspezifikation und der Bewertung der Homogenität der Schichtdicke auch bei kritischen Geometrien. Zur Validierung der Schichtdicken- bzw. Längenbestimmung im Querschliff wurde ein Laborvergleichsversuch mit einem Nickel-beschichteten Kupferdraht durchgeführt, den alle der 10 Teilnehmer bestanden.
T2 - 55. Materialographie-Tagung
CY - Online meeting
DA - 29.09.2021
KW - Metallographie
KW - Schichtdicken
KW - Korrosion
KW - Kalottenverfahren
PY - 2021
AN - OPUS4-53504
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Additive Manufacturing: Opportunities and challenges for NDT
N2 - Additive manufacturing processes are increasingly being used in industrial applications. Especially powder bed fusion processes are of high interest due to their capability to economically produce individual, highly complex and functionally integrated components in small batches.
However, the quality assurance of these components remains a challenge. Internal defects and undesirable microstructures and surface conditions can deteriorate the mechanical properties. Especially for use in safety-relevant applications, new design and inspection concepts are needed that take these factors into account.
This talk presents typical defects and microstructure phenomena resulting from the laser powder bed fusion process and identifies challenges and opportunities for non-destructive testing from a manufacturing engineering perspective. In particular, the possibility of a process-integrated quality control is shown based on current research results.
T2 - The 13th International Symposium on NDT in Aerospace 2021
CY - Online meeting
DA - 05.10.2021
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - In-situ monitoring
PY - 2021
AN - OPUS4-53484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmies, Lennart
A1 - Sonntag, U.
T1 - Quantitative Fraktographie unter Verwendung klassischer Verfahren, Topographie-Daten und Deep-Learning
N2 - Die Analyse von Bruchflächen wird in der Schadensanalyse meist auf der Basis von Erfahrungswissen vorgenommen, welches aus vorliegenden Untersuchungen, eigenen Vergleichsversuchen und aus der Literatur stammt. Durch Vergleiche mit bereits vorliegenden Bildern werden qualitativ Bruchmechanismen ermittelt. Grundlage sind zumeist zweidimensionale Bilder aus licht- und elektronenoptischen Verfahren. Quantitative Aussagen beziehen sich bislang beispielsweise auf makroskopische Anteile von Bruchmechanismen oder die Ausmessung von Schwingstreifen. In jüngerer Zeit gibt es vermehrt Ansätze, Computer-Algorithmen einzusetzen, die in der Lage sind, unterschiedlich strukturierte Bruchmerkmale zu finden und zu klassifizieren. Im hier vorgestellten IGF-Vorhaben „iFrakto“, IGF Vorhaben Nr.: 21477 N, werden licht- und elektronen-optisch Topographie-Bilder erzeugt und die gewonnenen 3D-Informationen zusammen mit den klassischen 2D-Bildern ausgewertet. Analytische Algorithmen und Machine Learning werden eingesetzt, um Bruchmerkmale zu analysieren, zu bewerten und mit Informationen aus einer fraktographischen Datenbank zu verknüpfen. Ziel ist die Bereitstellung von Software zur Unterstützung der Fraktographie in der Schadensanalyse. In diesem Beitrag werden erste Ergebnisse des Vorhabens vorgestellt.
T2 - 55. Metallographie-Tagung
CY - Online meeting
DA - 29.9.2021
KW - Fraktographie
KW - Machine Learning
KW - Datenbank
KW - REM
KW - Topographie
PY - 2021
AN - OPUS4-53491
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - Coordination Polymers for the Applications in Electrochemical Devices
N2 - Coordination polymers can be used as sacrificial templates to prepare nitrogen- and metal doped carbons (NMCs), which are promising catalysts for the oxygen reduction reaction. We at BAM employ mechanochemistry as a "green" synthetic approach to coordiantion polymers, which are throroughly characterized by methods such as XRD, XPS and sorption studies. Our collaborators can prepare NMCs from our coordination polymers and assess the catalytic activity thereof.
T2 - 3rd Training School: "Mechanochemistry: from supramolecular to covalent bonds - synthesis and strctural characterization
CY - Lisbon, Portugal
DA - 22.03.2021
KW - PGM-free catalyst
KW - Mechanochemistry
KW - MOFs
KW - Electrocatalysis
KW - Oxygen reduction reaction (ORR)
PY - 2021
AN - OPUS4-53536
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Agea, Boris
A1 - Walzel, S.
T1 - 3D Druck unterstütz die Dekarbonisierung
N2 - Suspensionsbasiertes Binder Jetting reduziert die Brennzeiten von technischer Keramik im Vergleich zu anderen 3d-druckverfahren signifikant. dabei wird nicht nur Energie beim Betrieb der Brennöfen gespart, sondern auch die Emission von Kohlendioxid beim Brennvorgang selbst gesenkt.
KW - Schlickerdeposition
PY - 2021
VL - 6
SP - 26
EP - 28
PB - Keramische Zeitschrift
AN - OPUS4-53812
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Griesche, Axel
A1 - Pfretzschner, B.
A1 - Taparli, Ugur Alp
A1 - Kardjilov, N.
T1 - Time-Resolved Neutron Bragg-Edge Imaging: A Case Study by Observing Martensitic Phase Formation in Low Temperature Transformation (LTT) Steel during GTAW
N2 - Polychromatic and wavelength-selective neutron transmission radiography were applied during bead-on-plate welding on 5 mm thick sheets on the face side of martensitic low transformation temperature (LTT) steel plates using gas tungsten arc welding (GTAW). The in situ visualization of austenitization upon welding and subsequent α’-martensite formation during cooling could be achieved with a temporal resolution of 2 s for monochromatic imaging using a single neutron wavelength and of 0.5 s for polychromatic imaging using the full spectrum of the beam (white beam). The spatial resolution achieved in the experiments was approximately 200 µm. The transmitted monochromatic neutron beam intensity at a wavelength of λ = 0.395 nm was significantly reduced during cooling below the martensitic start temperature Ms since the emerging martensitic phase has a ~10% higher attenuation coefficient than the austenitic phase. Neutron imaging was significantly influenced by coherent neutron scattering caused by the thermal motion of the crystal lattice (Debye–Waller factor), resulting in a reduction in the neutron transmission by approx. 15% for monochromatic and by approx. 4% for polychromatic imaging.
KW - Austenite-to-martensite transformation
KW - Neutron radiography
KW - Bragg-edge imaging
KW - Gas tungsten arc welding (GTAW)
KW - Debye–Waller factor
KW - Low transformation temperature (LTT) steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538016
DO - https://doi.org/10.3390/app112210886
VL - 11
IS - 22
SP - 10886
PB - MDPI
CY - Basel
AN - OPUS4-53801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ivanov, S.
A1 - Gushchina, M.
A1 - Artinov, Antoni
A1 - Khomutov, M.
A1 - Zemlyakov, E.
T1 - Effect of Elevated Temperatures on the Mechanical Properties of a Direct Laser Deposited Ti-6Al-4V
N2 - In the present work, the mechanical properties of the DLD-processed Ti-6Al-4V alloy were obtained by tensile tests performed at different temperatures, ranging from 20 °C to 800 °C. Thereby, the process conditions were close to the conditions used to produce large-sized structures using the DLD method, resulting in specimens having the same initial martensitic microstructure. According to the obtained stress curves, the yield strength decreases gradually by 40% when the temperature is increased to 500 °C. Similar behavior is observed for the tensile strength. However, further heating above 500 °C leads to a significant increase in the softening rate. It was found that the DLD-processed Ti-6Al-4V alloy had a Young’s modulus with higher thermal stability than conventionally processed alloys. At 500 °C, the Young’s modulus of the DLD alloy was 46% higher than that of the wrought alloy. The influence of the thermal history on the stress relaxation for the cases where 500 °C and 700 °C were the maximum temperatures was studied. It was revealed that stress relaxation processes are decisive for the formation of residual stresses at temperatures above 700 °C, which is especially important for small-sized parts produced by the DLD method. The coefficient of thermal expansion was investigated up to 1050 °C.
KW - Direct laser deposition
KW - Ti-6Al-4V
KW - Mechanical properties
KW - Microstructure
KW - Stress relaxation
KW - Elevated temperatures
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538025
DO - https://doi.org/10.3390/ma14216432
SN - 1996-1944
VL - 14
IS - 21
SP - 1
EP - 17
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-53802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Carstensen, Niels
T1 - Generation of Tribosystems by Additive Surface Treatment on Tool Steel Substrate
N2 - Laser implantation aims at reducing friction and wear on highly stressed surfaces in forming processes. Especially the hot stamping process that is used as a resource efficient process for manufacturing geometrical complex and high-strength structures, exhibits severe wear and high friction during the forming operation. The laser implantation process addresses this problem by combining two different approaches (surface modification and surface structuring) in surface technology by creating elevated, highly wear-resistant micro-features to influence the tribological performance. Pure TiB2 implants have shown to reduce tool-sided wear significally and improve the part formability by reducing local necking in deep drawing tests. Within the scope of this work, TiB2-TiC and TiB2-TaC hard material mixtures are implanted on X38CrMoV5-3 hot work tool steel. The aim is to investigate how the implant material properties can be influenced by the application of different mixing ratios of hard material mixtures under the specific variation of the process parameters. Distinct implant formations are tested on a novel test apparatus to examine the influence on the tribological properties.
From the analyses of the implant properties by hardness measurements, light microscopic images, EDX and XRD analyses process parameter ranges are identified to produce defect-free dome- and ring-shaped implants. The specific process parameters (pulse power, pulse duration, mixing ratio and coating thickness) can be used for the determination of the implant geometry (height, width and depth). The tribological tests exhibit improved friction and wear properties. Based on these results, a tribosystem manufactured by this additive surface treatment technology shows great potential to enhance the effectiveness of the hot stamping process.
T2 - Friction 2021
CY - Sankt Augustin, Germany
DA - 18.11.2021
KW - Laser implantation
KW - Surface modification
KW - Additive surface treatment
KW - Hot stamping
KW - Tool steel
PY - 2021
AN - OPUS4-53809
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolzenberg, U.
A1 - Schmitt Rahner, M.
A1 - Pullner, B.
A1 - Legall, Herbert
A1 - Bonse, Jörn
A1 - Kluge, M.
A1 - Ortner, A.
A1 - Hoppe, B.
A1 - Krüger, Jörg
T1 - X-ray emission hazards from ultrashort pulsed laser material processing in an industrial setting
N2 - Interactions between ultrashort laser pulses with intensities larger than 10^13 W/cm^2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 10^15 W/cm^2 at pulse durations of ~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified.
KW - X-ray emission hazards
KW - Ultrashort pulsed laser
KW - Radiation protection
KW - Industrial applications
KW - Protection housing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538632
DO - https://doi.org/10.3390/ma14237163
SN - 1996-1944
VL - 14
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-53863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Legall, Herbert
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - Emission of X-rays during ultrashort pulse laser processing
N2 - Ultrashort pulse laser materials processing can be accompanied by the production of X-rays. Small doses per laser pulse can accumulate to significant dose rates at high laser pulse repetition rates which may exceed the permitted X-ray limits for human exposure. Consequently, a proper radiation shielding must be considered in laser machining. A brief overview of the current state of the art in the field of undesired generation of X-ray radiation during ultrashort pulse laser material processing in air is presented.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - Ultra-short pulse laser processing
KW - Laser-induced X-ray emission
KW - Radiation protection
PY - 2021
SP - 1
EP - 5
AN - OPUS4-53866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Halder, A.
A1 - Maiti, A.
A1 - Dinda, S.
A1 - Bhattacharya, Biswajit
A1 - Ghoshal, D.
T1 - Unraveling the Role of Structural Dynamism in Metal Organic Frameworks (MOF) for Excited-State Intramolecular Proton Transfer (ESIPT) Driven Water Sensing
N2 - Ligand based modification has been performed to synthesize a pair of
mixed ligands d10 MOF based materials related to a previously published compound as a base material. The previous compound was a Zn(II)-MOF, {[Zn(4-bpdh)(H2dht)](MeOH)(H2O)}n (1) [N,N′-bis(1-pyridin-4-yl-ethylidene)hydrazine = 4-bpdh and 2,5-dihydroxyterephthalic acid = H4dht], which is a five-fold interpenetrated framework and highly dynamic in nature. In the first synthetic modification, the central metal is replaced by Cd(II), which has the same framework formula as the base material, but this is a rigid compound and also there is no interpenetration in the framework. In the second modification, along with the metal center, the 4,4′- coordinating N,N′-donor ligand is replaced by an isomeric 3,3′-coordinating N,N′- donor linker. In this compound, the dynamism is regenerated. The dynamic nature can be realized by the extensive PXRD studies and characteristic “step-shaped” gas/solvent adsorption behavior for CO2, water, and ethanol. Furthermore, all these 3D MOFs show excited-state intramolecular proton transfer phenomena and water sensing properties in different organic solvents. Here excitingly, the ease of water sensing property is directly related to the dynamic behavior of the framework which has been studied thoroughly in terms of structural correlation.
KW - MOFs
PY - 2021
DO - https://doi.org/10.1021/acs.cgd.1c00446
SN - 1528-7483
VL - 21
IS - 11
SP - 6110
EP - 6118
PB - ACS Publications
AN - OPUS4-53903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Le, Quynh Hoa
A1 - Balzer, B
T1 - „Auffällige große Streifen“ im Schwingbruch
N2 - Die „auffälligen großen Streifen“ sind von echten Schwingstreifen nur sehr schwer zu trennen, weil sie parallel zu den Schwingstreifen verlaufen und meistens ebenfalls nicht sehr groß sind. Die im Labor getesteten Proben zeigten, dass diese großen Streifen zusammen mit Verreibungen auftraten und „tire tracks“ („Reifenspuren“) verursachten. Dies wurde durch eine hochauflösende REM-Untersuchung bestätigt, die „tire tracks“ auf den „großen Streifen“ zeigte. Ein weiterer Hinweis ist die Änderung des R-Werts von -1 auf 0,1, was zu einer Bruchfläche ohne große Streifen und „tire tracks“ führt.
T2 - Treffen der AG Fraktographie im Gemeinschaftsausschuss Rasterelektronenmikroskopie in der Materialprüfung
CY - Online meeting
DA - 19.11.2021
KW - Fractography
KW - Fracture surface
KW - SEM
KW - REM
KW - Fraktographie
KW - Schwingstreifen
KW - Fatigue
PY - 2021
UR - https://dgm.inventum.de/widget/preview/45d8c33d-622b-43e2-8459-ba783394a723/611d133ebdac0611d133ebdac1
AN - OPUS4-53796
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krietsch, Arne
A1 - Reyes Rodriguez, M.
A1 - Kristen, A.
A1 - Kadoke, D.
A1 - Abbas, Z.
A1 - Krause, U.
T1 - Ignition temperatures and flame velocities of metallic nanomaterials
N2 - The production of materials with dimensions in the nanometre range has continued to increase in recent years. In order to ensure safety when handling these products, the hazard potential of such innovative materials must be known. While several studies have already investigated the effects of explosions (such as maximum explosion pressure and maximum pressure rise) of powders with primary particles in the nanometre range, little is known about the ignition temperatures and flame velocities. Therefore, the minimum ignition temperature (MIT) of metallic nano powders (aluminium, iron, copper and zinc) was determined experimentally in a so called Godbert-Greenwald (GG) oven. Furthermore, the flame velocities were determined in a vertical tube. In order to better classify the test results, the tested samples were characterised in detail and the lower explosion limits of the tested dust samples were determined. Values for the burning velocity of aluminium nano powders are higher compared to values of micrometre powd
ers (from literature). While MIT of nanometre aluminium powders is within the range of micrometre samples, MIT of zinc and copper nano powders is lower than values reported in literature for respective micrometre samples.
KW - Dust explosions
KW - Nanomaterial
KW - Flame propagation
KW - Minimum ignition temperature
PY - 2021
DO - https://doi.org/10.1016/j.jlp.2021.104482
SN - 0950-4230
VL - 2021
IS - 71
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-54076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
T1 - Presenting “SLAMD” - The Sequential Learning App for Materials Discovery
N2 - Environmentally friendly alternatives to cement are created through the synthesis of numerous base materials. The variation of their proportions alone leads to millions of materials candidates. Identifying suitable materials is very laborious; traditional systematic research in the laboratory consumes a lot of time and effort.
Sequential learning (SL) potentially speeds up the materials research process despite limited but highly complex available information. SL does not make direct predictions of material properties but ranks possible experiments according to their utility. The most promising experiments are prioritized over dead-end experiments and experiments whose outcome is already known.
Our work has shown that SL seems to be promising for cement research. So far, research has mainly focused on materials whose synthesis is faster and whose material properties require less time for development or characterization (allowing many successive experiments). Contrarily, in the case of binders, SL is only useful if few experiments lead to the desired goal, as for example, the determination of the compressive strength alone typically requires 28 days.
In research practice, experimental designs and the availability of resources often determine which data can be used - for example, when some laboratory resources are not available or deemed irrelevant to a task. As a result, new research scenarios are constantly emerging, each of which requires to demonstrate SL’s performance.
We are presenting the SLAMD app to facilitate the exploration of SL methods in numerous research scenarios. The app provides flexible and low-threshold access to AI methods via intuitive and interactive user interfaces. We deliberately pursue a software-based research approach (as opposed to code-, or script-based). On the one hand, the results are more comprehensible since we refer to a common (code) basis (’reproducible science’). On the other hand, the methods are easily accessible to all which accelerates the knowledge transfer into laboratory practice.
T2 - DGM Materials Week 2021
CY - Online meeting
DA - 07.09.2021
KW - Sequential learning
KW - Scientific software
KW - Alcali activated binders
PY - 2021
AN - OPUS4-54128
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Albarrán Martínez, M. J.
A1 - Ghigo, Tea
T1 - The practice of writing inside an Egyptian monastic settlement
N2 - Over the last few years, the Federal Institute for material research (BAM, Berlin) together with the Centre for the Study of Manuscript Cultures (CSMC, University of Hamburg) have initiated a systematic material investigation of black inks produced from Late Antiquity to the Middle Ages (ca. fourth century CE–fourteenth/fifteenth centuries CE), aimed primarily at extending and complementing findings from previous sporadic studies. Part of this systematic investigation has focused on Egyptian Coptic manuscripts, and the present preliminary study is one of its outputs. It centres on a corpus of 45 Coptic manuscripts—43 papyri and 2 ostraca—preserved at the Palau-Ribes and Roca-Puig collections in Barcelona. The manuscripts come from the Monastery of Apa Apollo at Bawit, one of the largest monastic settlements in Egypt between the Late Antiquity and the Early Islamic Period (sixth–eighth centuries CE). The composition of their black inks was investigated in situ using near-infrared reflectography (NIRR) and X-ray fluorescence (XRF). The analyses determined that the manuscripts were written using different types of ink: pure carbon ink; carbon ink containing iron; mixed inks containing carbon, polyphenols and metallic elements; and iron-gall ink. The variety of inks used for the documentary texts seems to reflect the articulate administrative system of the monastery of Bawit. This study reveals that, in contrast to the documents, written mostly with carbon-based inks, literary biblical texts were written with iron-gall ink. The frequent reuse of papyrus paper for certain categories of documents may suggest that carbon-based inks were used for ephemeral manuscripts, since they were easy to erase by abrasion.
KW - Papyrus
KW - Ink analysis
KW - Coptic manuscripts
KW - Bawit
KW - Mixed ink
KW - Near-infrared refectography
KW - X-ray fuorescence
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528833
DO - https://doi.org/10.1186/s40494-021-00541-0
SN - 2050-7445
VL - 9
IS - 1
SP - 1
EP - 15
PB - Springer Open
CY - Rome, Italy
AN - OPUS4-52883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts-und Mitteilungsblatt, Band 51, Heft 1
T3 - Amts- und Mitteilungsblatt der BAM - 1/2021
KW - Anerkennungen
KW - Zulassungen
KW - Gefahrgutregeln
KW - Festlegungen
KW - Richtlinien
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527760
SN - 0340-7551
VL - 51
IS - 1
SP - 1
EP - 70
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-52776
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kauss, Norman
A1 - Heyn, A.
A1 - Michael, O.
A1 - Schymura, M.
A1 - Rosemann, P.
T1 - Application limits and sensitisation behaviour of the manganese- and nitrogen-alloyed austenitic stainless steel P2000 (X13CrMnMoN18-14-3)
N2 - Nickel‐free high‐nitrogen‐alloyed stainless steels like the P2000 (X13CrMnMoN18‐14‐3) were developed to enhance the strength and corrosion resistance of austenitic stainless steels like 304 and 316 while keeping the typical high ductility. The mechanical and corrosive properties of P2000 were investigated and compared with 304 and 316 to highlight the application opportunities of this new alloy. The microstructure of the solution‐annealed condition was characterised by electron backscatter diffraction and the mechanical properties were studied by uniaxial tensile tests, Charpy impact tests and hardness measurements. The passivation behaviour was analysed using the electrochemical potentiodynamic reactivation, whereas the pitting corrosion resistance was compared by pitting potentials and pitting temperatures. However, secondary thermal influences or suboptimal heat treatment can impair the corrosion resistance due to the precipitation of secondary phases and the resulting sensitisation. Thermodynamic calculations and artificial ageing treatment in the range of 500–900°C for up to 100 h were used to determine critical time–temperature parameters for sensitisation. The microstructure of the various aged states was evaluated by scanning electron microscopy and compared with the degrading corrosion resistance characterised by the KorroPad method.
KW - Austenitic stainless steel
KW - Electrochemical methods
KW - High‐nitrogen steel
KW - Mechanical properties
KW - Corrosion resistance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527925
DO - https://doi.org/10.1002/maco.202112450
VL - 71
IS - 10
SP - 1656
EP - 1667
PB - Wiley-VCH GmbH
AN - OPUS4-52792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Beck, Uwe
A1 - Hielscher-Hofinger, Stefan
A1 - Lerche, D.
A1 - Reetz, U.
T1 - Vorhaben ZENSUS, BAM Vh-Nr. 6768 „Zentrifugentechnologie zur statistischen Untersuchung von Stumpfklebungen“
N2 - Das Vorhaben ZENSUS beschäftigt sich mit der Erstellung eines Normenentwurfs bzw. einer normen-konformen Technischen Spezifikation für die Zentrifugen-basierte Prüfung der Klebfestigkeit von Stumpfklebungen. Das umfasst auch umfangreiche Validierungsversuche, um mögliche Unterschiede zwischen Kraft-gesteuerter (Zentrifuge) und Weg-gesteuerter (Zugprüfmaschine) bzw. ggf. dazu korrelierte Materialabhängigkeiten mit ihren Auswirkungen auf SOPs zu identifizieren. Die Zentri-fugen-basierte Mehr-Proben-Prüfung von bis zu 8 Klebverbunden wird im Weiteren mit CAT-Technologie („Centrifugal Adhesion Testing“) abgekürzt.
KW - Klebfestigkeit von Stumpfklebungen
KW - EN 15870
KW - Centrifugal Adhesion Testing (CAT) Technologie
KW - Zugprüfung mittels Zugprüfmaschine
KW - Zugprüfung mittels Zentrifugentechnologie
PY - 2021
SP - 1
EP - 28
AN - OPUS4-52858
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Gefährdung durch Röntgenstrahlung bei der UKP-Lasermaterialbearbeitung – eine Einführung
N2 - Der Vortrag gibt eine Einführung zur Gefährdung durch Röntgenstrahlung bei der Materialbearbeitung mit ultrakurzen Laserpulsen.
T2 - LEF - Laser in der Elektronikproduktion & Feinwerktechnik, LEF-Brick 4: Gefährdung durch Röntgenstrahlung bei UKP-Prozessen
CY - Online meeting
DA - 17.06.2021
KW - Ultrakurze Laserpulse
KW - Lasermaterialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
PY - 2021
AN - OPUS4-52864
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Emission of X-rays during ultrashort pulse laser processing
N2 - Ultrashort laser pulses have found their way into industrial material processing. They take advantage of the fact that moderate laser fluences can produce high quality material removal without significant thermal influence. The growing availability of powerful, highly repeating laser sources and an advanced laser beam control have favored these developments. However, the laser-matter interaction can be accompanied by the production of X-rays. Small doses per laser pulse can accumulate to significant dose rates at high laser pulse repetition rates which may exceed the permitted X-ray limits for human exposure. Consequently, a proper radiation shielding must be considered in laser material processing. The paper summarizes the current state of the art in the field of undesired generation of X-ray radiation during ultrashort pulse laser material processing in air.
T2 - LiM - Lasers in Manufacturing 2021
CY - Online meeting
DA - 21.06.2021
KW - Ultrashort laser pulses
KW - Material processing
KW - X-ray emission
KW - Radiation protection
PY - 2021
AN - OPUS4-52865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Mapping und Imaging modifizierter Oberflächen: Generische Kenngrößen, Fehlstellen, Reinigungszustand und Haftfestigkeit
N2 - Der Vortrag widmet sich dem Mapping und Imaging modifizierter Oberflächen: Generische Kenngrößen, Fehlstellen, Reinigungszustand und Haftfestigkeit. Es werden Untersuchungsmethoden zu ihrer Prüfung dargestellt.
T2 - 37. ak-adp 2021, Jena
CY - Online meeting
DA - 16.06.2021
KW - Qualitätssicherung
KW - Mapping modifizierter Oberflächen
KW - Generische Kenngrößen
KW - Haftfestigkeit
KW - Klebfestigkeit
PY - 2021
AN - OPUS4-52870
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Entwicklung thermoelektrischer Multilayergeneratoren auf der Basis von Calciumcobaltit
N2 - Thermoelectric generators can be used as energy harvesters for sensor applications. Multilayer thermoelectric generators (ML-TEGs) are a promising alternative to conventional π-type generators due to their high filling factor, high capability of automated production and the texturing potential during the production process. Calcium cobaltite is a promising thermoelectric oxide (p-type) with highly anisotropic properties. The following study shows the development of a textured unileg ML-TEG using ceramic multilayer technology.
Tape-casting and pressure assisted sintering are applied to fabricate textured calcium cobaltite. Compared to conventional sintering, pressure assisted sintering increases the strength by the factor 10. Thermoelectric properties can be tuned either towards maximum power factor or towards maximum figure of merit depending on the pressure level.
As electrical insulation material, a screen-printable glass-ceramic with high resistivity and adapted coefficient of thermal expansion is developed. From various commercial pastes a metallization with low contact resistance is chosen. The unileg ML-TEG is co-fired in one single step. The demonstrators reach 80% of the simulated output power and the power output is highly reproducible between the different demonstrators (99%). These results provide the first proof-of-concept for fabricating co-fired multilayer generators based on textured calcium cobaltite with high power factor, high density, and high strength.
N2 - Thermoelektrische Generatoren können zum „Energy harvesting“ für den autarken Betrieb von bspw. Sensoren eingesetzt werden. Eine interessante Alternative zu den herkömmlichen π-Typ Generatoren sind auf Grund der höheren Leistungsdichte und der guten Automatisierbarkeit thermoelektrische Multilayergeneratoren. Calciumcobaltit ist ein vielsprechendes oxidisches Thermoelektrika (p-Typ) mit stark anisotropen Eigenschaften. Die hier vorgestellte Studie zeigt die Entwicklung von texturierten Unileg-Multilayer-Generatoren mittels keramischer Multilayertechnologie.
Calciumcobaltit wird durch Foliengießen und druckunterstützte Sinterung texturiert. Im Vergleich zur konventionellen Sinterung verbessert sich die Festigkeit um den Faktor 10. Die thermoelektrischen Eigenschaften können je nach verwendetem Druckniveau hinsichtlich maximalem Power Factor oder hinsichtlich maximalem Gütefaktor optimiert werden.
Ein Glaskeramikkomposit wird als Isolationsmaterial mit hohem Volumenwiderstand und angepasstem Wärmeausdehnungskoeffizienten entwickelt. Der Unileg-Multilayer-Generator wird in einem Schritt co-gesintert. Die hergestellten Demonstratoren erreichen 80% der simulierten Output-Leistung. Diese Ergebnisse stellen den ersten Machbarkeitsnachweis für die Herstellung von co-gesinterten Multilayer-Generatoren aus texturiertem Calciumcobaltit mit hohem Power Factor und hoher Festigkeit dar.
T2 - Seminar des Lehrstuhls für Funktionsmaterialien, Universität Bayreuth
CY - Online meeting
DA - 18.06.2021
KW - Thermoelektrischer Generator
KW - Multilayertechnik
KW - Energy harvesting
PY - 2021
AN - OPUS4-52834
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Plichta, T.
A1 - Sirjovona, V.
A1 - Zvonek, M.
A1 - Kalinka, Gerhard
A1 - Cech, V.
T1 - The Adhesion of Plasma Nanocoatings Controls the Shear Properties of GF/Polyester Composite
N2 - High-performance fibre-reinforced polymer composites are important construction materials based not only on the specific properties of the reinforcing fibres and the flexible polymer Matrix but also on the compatible properties of the composite interphase. First, oxygen-free (a-CSi:H) and oxygen-binding (a-CSiO:H) plasma nanocoatings of different mechanical and tribological properties were deposited on planar silicon dioxide substrates that closely mimic E-glass. The nanoscratch test was used to characterize the nanocoating adhesion expressed in terms of critical normal load and work of adhesion. Next, the same nanocoatings were deposited on E-glass fibres, which were used as reinforcements in the polyester composite to affect its interphase properties. The shear properties of the polymer composite were characterized by macro- and micromechanical tests, namely a short beam shear test to determine the short-beam strength and a single fibre push-out test to determine the interfacial shear strength. The results of the polymer composites showed a strong correlation between the short-beam strength and the interfacial shear strength, proving that both tests are sensitive to changes in fibre-matrix adhesion due to different surface modifications of glass fibres (GF).
Finally, a strong correlation between the shear properties of the GF/polyester composite and the adhesion of the plasma nanocoating expressed through the work of adhesion was demonstrated.
Thus, increasing the work of adhesion of plasma nanocoatings from 0.8 to 1.5 mJ·m−2 increased the short-beam strength from 23.1 to 45.2 MPa. The results confirmed that the work of adhesion is a more suitable parameter in characterising the level of nanocoating adhesion in comparison with the critical normal load.
KW - Mechanical properties
KW - Plasma nanocoatings
KW - Glass fibre
KW - Polymer composite
KW - Short-beam strength
KW - Interfacial shear strength
KW - Work of adhesion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521844
DO - https://doi.org/10.3390/polym13040593
VL - 13
IS - 4
SP - 593
PB - MDPI
CY - Basel,Schweiz
AN - OPUS4-52184
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simões, R. G.
A1 - Melo, P. L. T.
A1 - Bernardes, C. E. S.
A1 - Heilmann, Maria
A1 - Emmerling, Franziska
A1 - Minas da Piedade, M. E.
T1 - Linking Aggregation in Solution, Solvation, and Solubility of Simvastatin: An Experimental and MD Simulation Study
N2 - The solubility is generally thought to be higher if the solvent effectively solvates solute molecules that are well-separated from each other. The present work suggests, however, that the formation of large solute aggregates does not necessarily imply less effective solvation and lower solubility. Measurements of the solubility of simvastatin (one of the most commonly prescribed antihyperlipidemic drugs) in three solvents with different polarities and protic characters, led to the solubility order acetone > ethyl acetate > ethanol, in the full temperature range covered by the experiments (283–308 K). An analysis of the structures of the different solutions on the basis of molecular dynamics simulation results indicated that this trend seems to be determined by a balance between the solute tendency toward aggregation and the ability of the solvent to efficiently solvate it, by integrating the cluster structures, regardless of their size, and effectively establishing solvent–solute interactions.
KW - Simvastatin
KW - Solubility
KW - API
KW - Aggregation
PY - 2021
DO - https://doi.org/10.1021/acs.cgd.0c01325
VL - 21
IS - 1
SP - 544
EP - 551
AN - OPUS4-52185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rabe, Torsten
A1 - Eichler, J.
A1 - Picht, G.
A1 - Rossner, W.
A1 - Stelter, M.
A1 - Voigt, I.
T1 - Digitalisierung der keramischen Fertigung - Herausforderungen und Chancen
N2 - Dieses Strategiepapier zielt darauf ab, Akteuren und Entscheidungsträgern den Status der Digitalisierung in der keramischen Fertigung, erfolgreiche Best-Practice-Beispiele aber auch die Herausforderungen nahezubringen, die es nun anzugehen gilt. Es ist die Vision, die Keramikfertigung durchgehend zu digitalisieren und alle Schritte des Produktkreislaufs lückenlos über die gesamte Wertschöpfungs- und Nutzungskette zu vernetzen: also eine Keramikindustrie 4.0 zu etablieren. Das Strategiepapier erfasst zunächst die Spezifität der keramischen Fertigung und nimmt eine Analyse des gegenwärtigen Standes der Digitalisierung in der keramischen Industrie vor, auch anhand einiger ausgewählter Beispiele aus der industriellen Praxis. Auf Basis der wesentlichen Bausteine für eine Fertigungsdigitalisierung werden schließlich die Chancen für Keramikproduzenten sowie der erforderliche Forschungs- und Entwicklungsbedarf aufgezeigt.
KW - Datenmanagement
KW - Digitalisierung
KW - Fertigungsprozess
KW - Keramik
KW - Sensorik
PY - 2021
SP - 1
EP - 39
PB - Deutsche Gesellschaft für Materialkunde (DGM) und Deutsche Keramische Gesellschaft (DKG)
CY - Köln
ET - 1000
AN - OPUS4-52708
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ehlers, Henrik
T1 - Online ET with MR Sensor Arrays for LPBF Parts
N2 - In this presentation we discuss the online monitoring of LPFB parts using eddy current testing with magenoresistive sensor arrays. The underlying principle, the developed hardware and the results of the firt online monitoring are described in the presentation.
T2 - 2. Online-Workshop "In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys "
CY - Online meeting
DA - 19.04.2021
KW - Eddy current testing
KW - LPBF
KW - GMR
KW - SLM
KW - Haynes282
KW - Additive manufacturing
PY - 2021
AN - OPUS4-52700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kempf, A.
A1 - Hilgenberg, Kai
T1 - Influence of heat treatments on AlSi10Mg specimens manufactured with different laser powder bed fusion machines
N2 - Mechanical properties such as ultimate tensile strength, yield strength, and tensile elongation of parts manufactured with Laser Powder Bed Fusion (L-PBF) can differ significantly after the building process limiting the advantage of production flexibility of that technology. At this background, the present work investigated the influence of post process heat treatments (HT) on microstructure, hardness, and tensile properties of AlSi10Mg specimens in different As-built (AB) conditions. For this purpose, two superordinate aspects were covered within this study. Firstly, various HTs were performed on specimens built-up with the same L-PBF machine applying the same parameter set-up. Results of tensile tests and hardness measurements were discussed considering the microstructural changes examined with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy as well as X-ray diffraction, and gathered in a material data map. Based on the observed microstructural changes and a calculated quality index which comprises strength and ductility properties, three HTs were selected for the second part of this work. Therein, the effect of these HTs on specimens fabricated with overall three L-PBF machines working with different raw materials, process parameters, and build-up strategies was studied. Specimens characterization included porosity measurements, the evaluation of material defects, microstructure analysis via SEM, hardness measurements, and tensile tests. It was found that strength properties in the AB condition revealed appreciable deviations: Values of yield strength and ultimate tensile strength were from 228 to 292 MPa and from 346 to 484 MPa, respectively. Whereas heat treated specimens at 300 °C for 0.5 as well as 2 h only exhibited slight differences in strength, a complete homogenization of strength properties was obtained after conducting a T6 HT. Nevertheless, ductility was not homogenized after heat treating caused by the presence of material defects such as keyhole pores and lack of fusion defects. It was shown that even slight differences in porosity determined in cross-sections can significantly affect ductility properties.
KW - Laser powder bed fusion
PY - 2021
DO - https://doi.org/10.1016/j.msea.2021.141371
SN - 0921-5093
VL - 818
SP - 141371
PB - Elsevier B.V.
CY - Berlin
AN - OPUS4-52741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Höhne, Patrick
T1 - Limits of computer tomography aided characterization of different types of porous ceramic materials
N2 - Ceramics with open porosity are attractive materials in many fields of applications covering medicine, catalysis, and filtration. Manifold technologies to produce porous ceramics are available, e.g. foaming and replica processes, resulting in various microstructures. Development and manufacturing of new materials is accelerating, while crucial characterization is becoming increasingly difficult and conventional measurements lack the desired speed. Computed tomography (CT) offers the possibility to three-dimensionally characterize entire samples with minimal sample preparation, while its main advantage is that it is non-destructive. Still, the assessment of quantitative results from CT measurements is not trivial.
The poster presents CT characterizations of newly developed as well as commercially available openly porous ceramic samples. Properties such as porosity, permeability or pore characteristics were measured conventionally and compared to results calculated from CT-measurements using the commercial software VG StudioMax.
The determined differences between measured and calculated values are presented and application areas as well as limits of the CT characterization are evaluated.
T2 - Jahrestagung der Deutschen keramischen Gesellschaft 2021
CY - Online Meeting
DA - 19.04.2021
KW - Ceramic
KW - Porosity
PY - 2021
AN - OPUS4-52724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolbe, M.
T1 - Explosivbearbeitung von Motorenbauteilen
N2 - Darstellung von Explosivplattieren als Fügeverfahren zur Herstellung von Anfangsformen zur Herstellung von Ventilen und Kolbenbodenteilen für maritime Motorenanwendungen.
T2 - 27. Sächsiche Fachtagung für Umformtechnik, TU BA Freiberg
CY - Online meeting
DA - 18.03.2021
KW - TTS
KW - Explosivplattieren
KW - Explosivstoffe
KW - Reibschweißen
KW - Fügen
PY - 2021
AN - OPUS4-52294
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Lohrer, Christian
A1 - Dudek, Gabriele
T1 - Kalte Pyrotechnik - ein heißes Thema
N2 - Beschreibung der Eigenschaften von vermeintlich kalter Pyrotechnik und die Gefährdungen bei der Verwendung. Beitrag ist als VS-NfD (Verschlusssache - Nur für den Dienstgebrauch) eingestuft.
KW - Aerosole
KW - Pyrotechnik
KW - Nitrocellulose
PY - 2021
SP - 32
EP - 38
PB - Bundeskriminalamt (BKA)
CY - Wiesbaden
AN - OPUS4-52400
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Florian, Camilo
A1 - Fischer, Daniel
A1 - Freiberg, K.
A1 - Duwe, M.
A1 - Sahre, Mario
A1 - Schneider, S.
A1 - Hertwig, Andreas
A1 - Krüger, Jörg
A1 - Rettenmayr, M.
A1 - Beck, Uwe
A1 - Undisz, A.
A1 - Bonse, Jörn
T1 - Single Femtosecond Laser-Pulse-Induced Superficial Amorphization and Re-Crystallization of Silicon
N2 - Superficial amorphization and re-crystallization of silicon in <111> and <100> orientation after irradiation by femtosecond laser pulses (790 nm, 30 fs) are studied using optical imaging and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) allows fast data acquisition at multiple wavelengths and provides experimental data for calculating nanometric amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. For a radially Gaussian laser beam and at moderate peak fluences above the melting and below the ablation thresholds, laterally parabolic amorphous layer profiles with maximum thicknesses of several tens of nanometers were quantitatively attained. The accuracy of the calculations is verified experimentally by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the superficial re-solidification of silicon after local melting by femtosecond laser pulses is drawn.
KW - Femtosecond laser
KW - Silicon
KW - Amorphization
KW - Crystallization
KW - Spectroscopic imaging ellipsometry
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523687
UR - https://www.mdpi.com/1996-1944/14/7/1651
DO - https://doi.org/10.3390/ma14071651
SN - 1996-1944
VL - 14
IS - 7
SP - 1651-1
EP - 1651-21
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-52368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Oertzen, Alexander
T1 - BAM Projects and Areas of Interest in Explosives and Testing
N2 - This is a short review on ongoing work and interests in Division 2.6 of BAM with a focus on transport regulations and related testing. The behaviour of primer caps in different packaging configurations is addressed and the new apparatus for the "Minimum Burning Pressure" test is presented. Further topics regarding classification are touched with the aim to attract comments and stimulate cooperation internationally.
T2 - IGUS EPP & CIE Virtual Meeting #1
CY - Online meeting
DA - 16.03.2021
KW - Explosives
KW - Class 1
KW - Classification
KW - Primer caps
KW - UN-test methods
PY - 2021
AN - OPUS4-52306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nolze, Gert
T1 - CALM down: Identifying unknown phases
N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined.
T2 - Chemnitz MTEX Workshop 2021
CY - Online meeting
DA - 08.03.2021
KW - EBSD
KW - Gitterkonstanten
KW - Phasenidentifikation
PY - 2021
AN - OPUS4-52345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Forero-Sandoval, I.
A1 - Cervantes-Alvarez, F.
A1 - Ramirez-Rincon, J.
A1 - Macias, J.
A1 - Pech May, Nelson Wilbur
A1 - Ordonez-Miranda, J.
A1 - Alvarado-Gil, J.
T1 - Percolation Threshold of the Thermal, Electrical and Optical Properties of Carbonyl-Iron Microcomposites
N2 - Composites made up of microparticles embedded in a polymeric matrix have attracted increasing attention due to the possibility of tailoring their physical properties by adding the adequate quantity of fillers. As the concentration of these fillers increases, their connectivity changes drastically at a given threshold and therefore the electrical, thermal and optical properties of these composites are expected to exhibit a percolation effect. In this work, the thermal and electrical conductivities along with the emissivity of Composites composed of carbonyl-iron microparticles randomly distributed in a polyester resin matrix are measured, for volume fractions ranging from 0 to 0.55. It is shown that both the thermal and electrical conductivities increase with the particles’ concentration, such that their percolation threshold appears at volume fractions of 0.46 and 0.38, respectively.
The emissivity, on the other hand, decreases as the fillers’ concentration increases, such that it exhibits a substantial decay at a volume fraction of 0.41. The percolation threshold of the emissivity is thus higher than that of the thermal conductivity, but lower than the electrical conductivity one. This dispersion on the percolation concentration is justified by the different physical mechanisms required to activate the electrical, thermal, and optical
responses of the considered composites. The obtained results thus show that the percolation phenomenon can efficiently be used to enhance or reduce the physical properties of particulate composites.
KW - Thermal conductivity
KW - Emissivity
KW - Thermal percolation threshold
PY - 2021
DO - https://doi.org/10.1007/s10443-021-09869-z
VL - 28
IS - 2
SP - 447
EP - 463
PB - Springer
AN - OPUS4-52355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - DNA based Reference Materials: In Biodosimetry and Pharmaceutical Quality Control
N2 - Applications of plasmid DNA base reference materials in dosimetry and pharmaceutical research.
T2 - Physical and Chemical Analysis of Polymers seminar
CY - Online meeting
DA - 29.03.2021
KW - Analytic
KW - Certification
KW - DNA
KW - Dosimetry
KW - Homogeneity
KW - Quality testing
KW - Reference material
KW - Referenzmaterialien
KW - Stability
KW - Dose
KW - Radiation
KW - Pharmacy
KW - Electrohpresis
PY - 2021
AN - OPUS4-52361
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Winkelmann, A.
A1 - Cios, G.
A1 - Tokarski, T.
T1 - Tetragonality mapping of martensite in high-carbon steel by EBSD
N2 - The locally varying tetragonality in martensite grains of a high-carbon steel (1.2 mass percent C) was resolved by electron backscatter diffraction (EBSD) with a spatial resolution in the order of 100 nm. Compared to spatially integrating X-ray diffraction, which yielded an average tetragonality fo c/a=1.05, the EBSD measurements in the scanning electron microscope allowed to image a local variation of the lattice papameter ration c/a in the range of 1.02 ≤ c/a ≤ 1.07. The local variation of tetragonality is confirmed by two different EBSD data analysis approaches based on the fitting of simulated to experimental EBSD patterns. The resulting EBSD-based tetragonality maps are pointing to a complex interaction of carbon concentration and local lattice distortions during the formation process of martensitic structures.
KW - EBSD
KW - Martensite
KW - Tetragonal distortion
KW - Pattern matching
PY - 2021
DO - https://doi.org/10.1016/j.matchar.2021.111040
VL - 175
SP - 111040
PB - Elsevier Inc.
AN - OPUS4-52343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahrbach, M.
A1 - Friedrich, Sebastian
A1 - Behle, H.
A1 - Xu, Min
A1 - Cappella, Brunero
A1 - Brand, U.
A1 - Peiner, E.
T1 - Customized piezoresistive microprobes for combined imaging of topography and mechanical properties
N2 - Customized piezoresistive cantilever microprobes with a deflection range of 120 μm and silicon tips of 100 μm height were operated in a Cypher AFM showing their functionality for measuring topography together with stiffness, adhesion, and viscoelastic properties of thin films.
KW - Cantilever microprobe
KW - Piezoresistive
KW - Atomic force microscopy
KW - Force-distance curves
KW - Contact resonance
KW - Lubricants
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524225
DO - https://doi.org/10.1016/j.measen.2021.100042
VL - 15
SP - 100042
PB - Elsevier Ltd.
AN - OPUS4-52422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Tensile Test: From Standard to PMD Application Ontology
N2 - Data analysis methods play an important role in both the experimental and simulation-based digital description of materials but have so far been poorly structured. The platform Material Digital (PMD) should contribute to a standardized description of data processing methods in materials research. The goal is the quality assurance of the processes and the output data, the acquisition and definition of their accuracy as well as the interoperability between applications.
Therefore, application ontologies are created to explicitly describe processes and test methods. In this presentation, the first efforts in creating a tensile test application ontology in accordance with the ISO standard 6892-1:2019-11 are shown. Especially, the path of ontology development to be pursued based on standards was focused.
T2 - Onboarding Workshop der Plattform Material Digital (PMD)
CY - Online meeting
DA - 13.04.2021
KW - Ontology
KW - Platform MaterialDigital
KW - PMD
KW - Tensile Test
KW - Normung
KW - Standardization
PY - 2021
AN - OPUS4-52425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, M. A.
A1 - Khan, I.
A1 - Dören, R.
A1 - Ashraf, M.
A1 - Qurashi, A.
A1 - Prädel, L.
A1 - Panthöfer, M.
A1 - von der Au, Marcus
A1 - Cossmer, Antje
A1 - Pfeifer, Jens
A1 - Meermann, Björn
A1 - Mondeshki, M.
A1 - Tahir, M. N.
A1 - Tremel, W.
T1 - High-speed solid state fluorination of Nb2O5 yields NbO2F and Nb3O7F with photocatalytic activity for oxygen evolution from water
N2 - Solid state reactions are slow because the diffusion of atoms or ions through the reactant, intermediate and crystalline product phases is the rate-limiting step. This requires days or even weeks of high temperature treatment, and consumption of large amounts of energy. We employed spark-plasma sintering, an engineering technique that is used for high-speed consolidation of powders with a pulsed Electric current passing through the sample to carry out the fluorination of niobium oxide in minute intervals. The approach saves time and large amounts of waste energy. Moreover, it allows the preparation of fluorinated niobium oxides on a gram scale using poly (tetrafluoroethylene) (®Teflon) scrap and without toxic chemicals.
The synthesis can be upscaled easily to the kg range with appropriate sintering equipment. Finally, NbO2F and Nb3O7F prepared by spark plasma sintering show significant photoelectrocatalytic (PEC) oxygen evolution from water in terms of photocurrent density and incident photon-to-current Efficiency (% IPCE), whereas NbO2F and Nb3O7F prepared by conventional high temperature chemistry show little to no PEC response. Our study is a proof of concept for the quick, clean and energy saving production of valuable photocatalysts from plastic waste.
KW - Fluorination
KW - Nb2O5, NbO2F, Nb3O7F
KW - Photocatalytic activity
PY - 2021
DO - https://doi.org/10.1039/d1dt00533b
VL - 50
IS - 19
SP - 6528
EP - 6538
PB - Royal Society of Chemistry
AN - OPUS4-52439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stargardt, Patrick
T1 - Modeling of the cooling behavior of thermoelectric multilayers
N2 - Multilayered designs are an attractive approach towards cost-effective manufacturing of thermoelectric generators. Therefore, efforts are being made to co-fire two promising thermoelectric oxides, namely calcium cobaltite and calcium manganate. In this study, ceramic tapes, multilayer technology, and pressure-assisted sintering (PAS) were used. A major challenge for the PAS of low-sintered calcium manganate was cracking during cooling. A relationship between the properties of the release tape used during PAS and the cracking behavior was experimentally observed.
To understand the origin of failure, reaction layers in the multilayer were analyzed and thermal stresses during cooling were estimated by finite element (FE) simulations. Thermal expansion, elastic properties, and biaxial strength of the thermoelectric oxides and selected reaction layers were determined on separately prepared bulk samples. The analysis showed that the reaction layers were not the cause for cracking of calcium manganate.
Using the FE model, thermal stresses in different manganate multilayer designs with varying properties of the release tape were studied. The FEM study indicated, and a validation experiment proved that the thickness of the release tape has the main effect on thermal stresses during cooling in separately sintered calcium manganate.
T2 - Keramik 2021 / Ceramics 2021
CY - Online Meeting
DA - 19.04.2021
KW - Fem
KW - Thermoelectric
KW - Pressure assisted sintering
PY - 2021
AN - OPUS4-52489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wilke, Olaf
T1 - Contaminants of Emerging Concern from Materials and Products: Measurement and Evaluation
N2 - Test chamber measurements are an important tool to improve indoor air quality and occupational safety. Test chamber measurements are possible for a wide range of materials, products and technologies. Determination of concerning contaminants is important to ensure good indoor air quality. The detection of concerning contaminants depends on the approriate sampling and analysis.
T2 - Webinar BAM-University of Birmingham
CY - Online meeting
DA - 24.02.2021
KW - Emerging Contaminants
KW - Emission Test Chamber
KW - Thermal Extraction
KW - Thermal Desorption
PY - 2021
AN - OPUS4-52262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Walter, Astrid
A1 - Costard, René
A1 - Dengel, Jörg
T1 - Aktuelles aus der Normung von Explosivstoffen & Pyrotechnik
N2 - In diesem Beitrag wird über den aktuellen Stand der Normfortentwicklung auf europäischer Ebene im Bereich der Explosivstoffe und Pyrotechnik berichtet. Gemäß der jeweiligen Normungsaufträge werden sämtliche harmonisierten Normen bzw. Normenreihen beider Fachgebiete überarbeitet. Neben der Anpassung an die neuen Richtlinien und dem Überprüfen des Stands der Technik werden auch weitere inhaltliche Neuerungen vorgenommen. In der Pyrotechnik wird unter anderem die verstärkte Einbeziehung von Umweltaspekten sowie die Schärfung der Abgrenzungskriterien zum Feuerwerk im Fokus stehen. Bei den Explosivstoffen sind die elektronischen Zündsysteme und die vor Ort hergestellten Sprengstoffe (MEMUs) bislang unzureichend durch Normen abgedeckt und werden nun berücksichtigt. Dieser Beitrag soll auch aufzeigen, welche Herausforderungen sich bei der Arbeit an den Normen ergeben.
T2 - Explosivstoffgespräch 2021
CY - Online meeting
DA - 26.04.2021
KW - Explosivstoffe
KW - Pyrotechnische Gegenstände
KW - Normung
PY - 2021
AN - OPUS4-52518
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Charmi, Amir
T1 - Mechanical anisotropy of LPBF 316L: a modeling approach
N2 - The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures.
To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF).
Tensile specimens were machined from these AM bulk materials for three different inclinations relative to the build plate. Dynamic Young's modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography, and texture analysis with electron backscatter diffraction (EBSD). A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture.
T2 - 2. Online-Workshop "In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys "
CY - Online meeting
DA - 20.04.2021
KW - Anisotropy
KW - Crystal plasticity
KW - Additive manufacturing
PY - 2021
AN - OPUS4-52603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ayerdi, J. J.
A1 - Aginagalde, A.
A1 - Llavori, I.
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
A1 - Zabala, A.
T1 - Ball-on-flat linear reciprocating tests: Critical assessment of wear volume determination methods and suggested improvements for ASTM
N2 - In the present work it was shown the importance of the correct selection, implementation, and reporting of wear volume computation method and quanitifies the potential errors.
KW - Wear
KW - Sliding
KW - Surface
KW - Analysis
KW - ASTM
KW - D7755-11
PY - 2021
DO - https://doi.org/10.1016/j.wear.2021.203620
VL - 470-471
SP - 3620
AN - OPUS4-52080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frisch, M.
A1 - Laun, J.
A1 - Marquardt, Julien
A1 - Arinchtein, A.
A1 - Bauerfeind, K.
A1 - Bernsmeier, D.
A1 - Bernicke, M.
A1 - Bredow, T.
A1 - Kraehnert, R.
T1 - Bridging experiment and theory: enhancing the electrical conductivities of soft-templated niobium-doped mesoporous titania films†
N2 - Theoretical calculations suggest a strong dependence of electrical conductivity and doping concentration in transition-metal doped titania. Herein, we present a combined theoretical and experimental approach for the prediction of relative phase stability and electrical conductivity in niobium-doped titania as model system.
Our method paves the way towards the development of materials with improved electrical properties.
KW - Electrical conductivity
KW - Prediction relative
KW - Transition-metal doped
KW - System method
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521371
DO - https://doi.org/10.1039/d0cp06544g
SN - 1463-9084
VL - 23
IS - 5
SP - 3219
EP - 3224
PB - Royal Society of Chemistry
AN - OPUS4-52137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Geschäftsbericht der Konformitätsbewertungsstelle Explosivstoffe / Pyrotechnik
N2 - Es werden die Aktivitäten im Fachbereich 2.5 aus dem Jahr 2020 dargestellt: Konformitätsbewertungen (auch unter Maßgabe von COVID-19), Normung, FE und Beratung.
T2 - 23. Beiratssitzung der BAM-Zertifizierungsstelle (BZS)
CY - Online meeting
DA - 17.02.2021
KW - Security
KW - Explosivstoffe
KW - Pyrotechnik
KW - Konformitätsbewertung
KW - Normung
PY - 2021
AN - OPUS4-52139
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
A1 - Trappe, Volker
T1 - Non-destructive characterization methods for polymer matrix composites
N2 - The mechanical behavior of fiber reinforced composites with polymer matrix is governed by several mechanisms operating at different length scales. In this contribution we describe first non-destructive techniques which are adequate for the characterization of the fiber-matrix interphase at a microscopic level. In a second step we describe on a mesoscopic level the influence of manufacturing related elements on the mechanical properties of rotor blades for wind turbines. We concentrate on thermography, laminography and ultrasound in connection with mechanical testing systems. Finally we present methods for monitoring rotor blades by using embedded optical fibers.
T2 - Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ, Brasilien
CY - Online meeting
DA - 26.11.2020
KW - Polymer matrix composites
PY - 2020
AN - OPUS4-52043
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
T1 - Charakterisierung metallischer Werkstoffe für Anwendungen bei hohen Temperaturen
N2 - In diesem Beitrag werden am Beispiel von Gasturbinen Verfahren zur Charakterisierung des werkstoff-mechanischen Verhaltens sowie der Gefügeentwicklung von Bauteilen für Anwendungen bei hohen Temperaturen aufgezeigt. Gasturbinen sind technisch gesehen sehr interessante Systeme, die in der Energietechnik und in der Luftfahrt von hoher wirtschaftlicher Relevanz sind. Seit Jahrzehnten gelten Gasturbinen als klassische Innovationstreiber, für ihre Entwicklung wurden bereits maßgebliche Erneuerungen im Bereich der Aerodynamik und der Werkstofftechnik hervorgebracht.
T2 - Deutsche Physikalische Gesellschaft Senior Expert Netzwerk
CY - Online meeting
DA - 20.01.2021
KW - Superlegierungen
KW - Gasturbinen
PY - 2020
AN - OPUS4-52045
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Large scale multi-parameter analysis of wear of self-mated 100Cr6 steel - A study of the validity of Archard's law
N2 - Considerable scattering of experimental wear results affects seriously the evaluation of repeatability and reproducibility of tribological measurements and hampers detecting, studying, and verifying tribological laws. An accurate characterization of the statistics of results, the detection of the influence of operating parameters, and the verification of equations describing tribological phenomena can be achieved only through the analysis of large datasets with wide variation of parameters. Taking advantage of more than 400 experiments performed with the same material pairing under the same conditions on four different tribometers, the repeatability and reproducibility of volumetric wear measurements has been evaluated using Welch's test.
By testing Archard's law over seven orders of magnitude of sFN, it was found that this law is not universally valid and that, under certain conditions, the wear coefficient depends on sFN itself.
KW - Wear
KW - Archard's law
KW - 100Cr6 steel
KW - Scattering
PY - 2021
DO - https://doi.org/10.1016/j.triboint.2021.106945
VL - 159
SP - 6945
PB - Elsevier Ltd.
AN - OPUS4-52244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
A1 - Krebber, Katerina
T1 - Fiber Optic Sensors for SHM - From Laboratory to Industrial
N2 - The paper highlights the research activities in Germany and Europe in the development of distributed fiber optic sensor for structural health monitoring (SHM) like the monitoring of geotechnical and civil infrastructures and presents selected results achieved within these projects.
T2 - Conaendi & IEV 2021
CY - Online meeting
DA - 09.03.2021
KW - Fiber
KW - Optic
KW - SHM
PY - 2021
AN - OPUS4-52254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Legall, Herbert
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - Review of x-ray exposure and safety issues arising from ultra-short pulse laser material processing
N2 - Laser processing with ultra-short laser pulses enables machining of materials
with high accuracy and throughput. The development of novel laser Technologies with laser pulse repetition rates up to the MHz range opened the way for industrial manufacturing processes. From a radiological point of view this evolution is important, because x-ray radiation can be generated as an unwanted side effect in laser material processing. Even if the emitted x-ray dose per pulse is comparably low, the x-ray dose can become hazardous to health at high laser repetition rates. Therefore, radiation protection must be considered. This article provides an overview on the generation and detection of x-rays in laser material processing, as well as on the handling of this radiation risk in the framework of radiological protection.
KW - Ultra-short pulse laser processing
KW - Laser-induced x-ray emission
KW - Radiation protection
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522376
DO - https://doi.org/10.1088/1361-6498/abcb16
VL - 41
IS - 1
SP - R28
EP - R42
AN - OPUS4-52237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thomas, Maximilian
T1 - Digitalisierung in der Heißrissprüfung - Wie viel Information steckt in einer MVT-Probe?
N2 - Die im MVT-Test standardmäßig erfasste Gesamtrisslänge erlaubt keine direkten Rückschlüsse auf die Heißrissanfälligkeit des untersuchten Werkstoffs. Der vorliegende Beitrag erläutert, inwiefern aus der Morphologie von Oberflächenrissen an MVT-Proben dennoch auf das Werkstoffverhalten geschlossen werden kann.
T2 - Jährl. Sitzung des DIN/DVS Normenausschuss 092-00-05 GA
CY - Online meeting
DA - 10.03.2021
KW - MVT
KW - Varestraint
KW - Heißriss
KW - Erstarrungsriss
PY - 2021
AN - OPUS4-52243
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Hemingway, J.
A1 - Morrison, C.
T1 - Predicting the Impact Sensitivities of Energetic Materials through Zone-Center Phonon Up-Pumping
N2 - The development of new energetic materials (EMs) is accompanied by significant hazards, prompting interest in their computational design. Before reliable in silico design strategies can be realized, however, approaches to understand and predict EM response to mechanical impact must be developed. We present here a fully ab initio model based in phonon up-pumping which successfully ranks the relative impact sensitivity of a series of organic EMs. The methodology depends only on the crystallographic unit cell and Brillouin zone center vibrational frequencies. We therefore expect this approach to become an integral tool in the large-scale screening of potential EMs.
KW - Energetic materials
KW - Ab initio simulation
PY - 2021
DO - https://doi.org/10.1063/5.0036927
VL - 154
IS - 6
SP - 064105
AN - OPUS4-52146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.
A1 - Camin, B.
A1 - Hansen, L.
A1 - Chyrkin, A.
A1 - Nolze, Gert
T1 - Synchrotron Sub-μ X-ray Tomography of Kirkendall Porosity in a Diffusion Couple of Nickel-Base Superalloy and Nickel after Annealing at 1250 °C
N2 - Kirkendall porosity that forms during interdiffusion in a diffusion couple of nickel-base superalloy CMSX-10 with pure nickel is investigated. The diffusion experiments are conducted at a temperature of 1250 °C, where the strengthening ƴ'-phase ist partially dissolved. The porosity is studied by X-ray sub-μ tomography with a spatial resolution of about 0.35³ μm³ at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. It is found that depending on the distance from the interface the Kirkendall pores take different shapes: octahedral, rounded pyramidal, drop shaped, dendritic, pear shaped, and joint shapes. Such a variety of pore morphologies indicates a complex multistage process of porosity nucleation and growth under vacancy supersaturation of different degrees. The experimental findings are interpreted on the basis of the results of diffusion modeling. It is shown that the kinetics of porosity growth is essentially influenced by the dissolution of the ƴ'-phase.
KW - Diffusion
KW - Nickel alloys
KW - Porous materials
KW - Synchrotron radiations
KW - Three-dimensional tomographies
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521476
DO - https://doi.org/10.1002/adem.202001220
VL - 23
IS - 4
SP - 1220
PB - Wiley Online Library
AN - OPUS4-52147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
T1 - Joining dissimilar materials a new approach based on laser beam welding and melt displacement by electromagnetic forces
N2 - In order to reduce weight of vehicles, the interest in multi-material-design has been growing within the last few years. For vehicles the combination of steel and aluminium alloys offers the most promising compromise between weight, strength and formability. Thermal joining of these dissimilar materials is still a challenge to overcome. A possible approach is a new joining technology, whereby a combination of laser beam welding and contactless induced electromagnetic forces are used to displace the generated melt of one joining partner into a notch of the other. This paper presents the working principle and shows numerical analyses to improve the understanding of this joining process. The simulations help to calculate the thermal development of the joining partners, which is important for the formation of intermetallic phases. Furthermore, the calculation of the time required for a complete displacement is possible. The numerical results are validated by experimental results.
T2 - LiM 2021
CY - Online meeting
DA - 21.06.2021
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Electromagnetic forces
KW - Steel and aluminium
PY - 2021
AN - OPUS4-52977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
A1 - Bachmann, Marcel
A1 - Hilgenberg, Kai
T1 - Joining dissimilar materials a new approach based on laser beam welding and melt displacement by electromagnetic forces
N2 - In order to reduce weight of vehicles, the interest in multi-material-design has been growing within the last few years. For vehicles the combination of steel and aluminium alloys offers the most promising compromise between weight, strength and formability. Thermal joining of these dissimilar materials is still a challenge to overcome. A possible approach is a new joining technology, whereby a combination of laser beam welding and contactless induced electromagnetic forces are used to displace the generated melt of one joining partner into a notch of the other. This paper presents the working principle and shows numerical analyses to improve the understanding of this joining process. The simulations help to calculate the thermal development of the joining partners, which is important for the formation of intermetallic phases. Furthermore, the calculation of the time required for a complete displacement is possible. The numerical results are validated by experimental results.
T2 - LiM 2021
CY - Online meeting
DA - 21.06.2021
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Electromagnetic forces
KW - Steel and aluminium
PY - 2021
SP - 1
EP - 9
PB - Wissenschaftliche Gesellschaft Lasertechnik e.V. (WLT)
AN - OPUS4-52978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Stephan-Scherb, Christiane
ED - Schorr, S.
ED - Weidenthaler, C.
T1 - Crystallographic challenges in corrosion research
N2 - High-temperature corrosion is a widespread problem in various industries.
As soon as a hot and reactive gas (CO2, O2, H2O, SO2, NOx, etc.) is in contact with a solid, physico-chemical processes at the surface and interfaces lead to material degradation. The processes are dynamic and controlled by thermodynamic and kinetic boundary conditions. Whether a reaction product is protective or not depends on various factors, such as chemical composition of the solid and the reactive media, surface treatment as well as diffusion and transport paths of cations and anions. Resulting chemical and structural inhomogeneities with the corrosion layers are characterized by off stoichiometry within cationic and anionic sub lattices. The competitive processes can be studied by various techniques of applied crystallography.
This chapter gives an overview on the challenges of chemical-structural Analysis of reaction products by crystallographic methods such as X-ray diffraction and X-ray near-edge structure spectroscopy and scanning electron microscopy electron backscatter diffraction (SEM-EBSD) for corrosion science.
KW - High-temperature corrosion
KW - Oxidation
KW - Diffraction
KW - Spectroscopy
KW - Oxides
PY - 2021
DO - https://doi.org/10.1515/9783110674910-009
SP - 291
PB - De Gruyter
ET - 1
AN - OPUS4-52903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Agea Blanco, Boris
A1 - Walzel, S.
A1 - Chi, J.
A1 - Lüchtenborg, J.
T1 - Making Binder Jetting Really Work for Technical Ceramics - Additive Manufacturing of Technical Ceramics
N2 - As an alternative shaping method to the traditionally used processes, additive manufacturing (AM) can produce economical ceramic components in small lot sizes and/or with complex geometries. Powder-based additive manufacturing processes like binder jetting are popular in the field of metal AM. One reason is the increased productivity compared to other AM technologies. For ceramic materials, powder-based AM technologies result in porous ceramic parts, provided they are not infiltrated. CerAMing GmbH unites the advantages of powder-based processes with the production of dense ceramic by means of the Layerwise Slurry Deposition. By using a suspension, a high packing density of the powder bed is achieved which leads to high green body densities. Due to this advantage the approach overcomes the problems of other powder-based AM technologies. Furthermore, a very economical debinding time allows the production of parts with high wall thicknesses.
KW - Additive Manufacturing
KW - Binder Jetting
KW - Layerwise Slurry Deposition
KW - Lithography-based technologies
KW - Technical Ceramics
PY - 2021
SP - 49
EP - 52
PB - Göller Verlag
CY - Baden-Baden
AN - OPUS4-52948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Tensile Test Ontology used in Platform Material Digital (PMD)
N2 - Data analysis methods play an important role in both the experimental and simulation-based digital description of materials but have so far been poorly structured. The platform Material Digital (PMD) is supposed to contribute to a standardized description of data processing methods in materials research. The goal is the quality assurance of the processes and the output data, the acquisition and definition of their accuracy as well as the interoperability between applications.
Therefore, application ontologies are created to explicitly describe processes and test methods. In this presentation, the first efforts within the joint project PMD in creating a tensile test application ontology in accordance with the ISO standard 6892-1:2019-11 are shown. Especially, the path of ontology development to be pursued based on standards was focused. Furthermore, the presentation includes a live demonstration of queries possibly performed to query data that was uploaded in the PMD triple store.
T2 - Online Workshop: An introduction to the semantic web and ontologies
CY - Online meeting
DA - 23.04.2021
KW - Ontology
KW - Tensile Test
KW - Platform Material Digital
KW - PMD
KW - Knowledge Graphs
KW - Semantic Web
PY - 2021
AN - OPUS4-52949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Even, Morgane
A1 - Hutzler, C.
A1 - Wilke, Olaf
A1 - Luch, A.
T1 - Emissions of volatile organic compounds from polymer-based consumer products: comparison of three emission chamber sizes
N2 - The ISO 16000 standard series provide guidelines for emission measurements of volatile organic compounds (VOCs) from building materials. However, polymer-based consumer products such as toys may also release harmful substances into indoor air. In such cases, the existing standard procedures are unsuitable for official control laboratories due to high costs for large emission testing chambers. This paper aims at developing and comparing alternative and more competitive methods for the emission testing of consumer products. The influence of the emission chamber size was investigated as smaller chambers are more suited to the common size of consumer products and may help to reduce the costs of testing. Comparison of the performance of a 203 l emission test chamber with two smaller chambers with the capacity of 24 l and 44 ml, respectively, was carried out by using a polyurethane reference material spiked with 14 VOCs during the course of 28 days. The area-specific emission rates obtained in the small chambers were always similar to those of the 203 l reference chamber after a few hours. This implies that smaller chambers can provide at least useful numbers on the extent of polymer-based consumer product emissions into indoor air, thereby supporting meaningful exposure assessments.
KW - Comparison
KW - Consumer products
KW - Emission chamber
KW - Reference material
KW - Volatile organic compounds
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-493697
DO - https://doi.org/10.1111/ina.12605
VL - 30
IS - 1
SP - 40
EP - 48
PB - Wiley VCH-Verlag
AN - OPUS4-49369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
A1 - Bachmann, Marcel
T1 - An electromagnetic approach to dissimilar metal welding
N2 - To save weight without affecting the functional properties of vehicles, heavy materials must be replaced with lighter alternatives.Modern lightweight concepts have therefore been developed, featuring multi-material designs that require the joining of dissimilar materials.One new possible approach for the joining of dissimilar metals is based on laser welding and melt displacement by contactless induced electromagnetic forces.
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Electromagnetic forces
KW - Steel and aluminium
PY - 2021
SP - 1
EP - 5
AN - OPUS4-53373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duwe, M.
T1 - Thickness Profiling of the Superficial Amorphization and Re-Crystallization of Silicon Induced by Femtosecond Laser Pulses
N2 - Crystalline Silicon undergoes a complex phase-change dynamic of melting, amorphization, ablation and re-crystallization upon irradiation with high intensity ultra-short laser pulses [1]. The final state of such a modified surface spot depends on many factors, most notably the local fluence and the surface’s crystal orientation. In this study, we induced superficial structure and phase changes in Silicon <111> and <100> wafers using single femtosecond laser pulses (790 nm, 30 fs) for a range of different peak fluences. The resulting surface modifications were studied in great detail using a number of different techniques, including spectroscopic imaging ellipsometry (SIE), atomic force microscopy, high-resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray spectroscopy within scanning transmission electron microscopy (STEM-EDX).
Playing a pivotal role in this work, SIE provided non-destructive measurements for the calculation of the radial amorphous layer-thickness profiles of the irradiated spots using a two-layer thin-film model (Silicon dioxide and amorphous Silicon on a crystalline Silicon substrate). The measurements further allowed for the analysis of the oxide-layer modifications induced by the laser treatment. The results of the SIE-calculations were cross-checked by an in-depth material lamella via HRTEM and STEM-EDX.
T2 - 11th Workshop Ellipsometry (WSE 11)
CY - Steyr, Austria
DA - 06.09.2021
KW - Femtosecond Laser
KW - Spectroscopic imaging ellipsometry
KW - Amorphization
KW - Ablation
KW - Re-crystallization
PY - 2021
AN - OPUS4-53363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
T1 - Acoustic emission of fibre reinforced AlSi12CuMgNi alloy under compression
N2 - Typically, the near-eutectic Al-Si alloys consist of highly interconnected three-dimensional network of the eutectic Silicon (Si) and intermetallics embedded into Aluminium (Al) matrix. For further improvement of the mechanical properties of such alloys, often, one single ceramic reinforcement phase, e.g. silicon carbide (SiC) or aluminium oxide (Al2O3) in the form of fibres or particles is added. However, hybrid reinforcements (fibres and particles) can further improve wear resistance and fracture toughness, and additionally, reduce anisotropy of the material. The engineering of metal matrix composites (MMC) for specific application requirements benefits from a comprehensive knowledge of the failure behaviour. Therefore, damage evolution under compression was investigated on:
- pure near-eutectic AlSi12CuMgNi matrix alloy
- type I: matrix reinforced with random-planar oriented Al2O3 short fibres (15 vol.%)
- type II: matrix reinforced with random-planar oriented Al2O3 short fibres (7 vol.%) and additional SiC particles (15 vol.%)
The analysis of damage mechanism was carried out in two rather independent but complementary studies. First, selected sister samples of every material were exposed to quasi-static compression (traverse control). The compression tests were interrupted at different strain levels. Miniature cylinders with a diameter of 1mm were extracted from the pre-strained samples and investigated by synchrotron computed tomography (SX-µCT) with a spatial resolution of about 0.7 µm. For the pure matrix alloy, microcracks are confined to the intermetallic particles and to the eutectic Si, hence no damage was observed in the Aluminium. The composite type II revealed a more effective strain accumulation (less damage) than type I at low plastic strain (up to 5 %), but a more catastrophic damage development due to cracking of the SiC clusters at higher strain levels.
The second approach to study the damage initiation and accumulation in the materials subjected to compressive load was Acoustic Emission (AE) analysis. In this case the in-situ monitoring of the acoustic emission signal was performed during compression tests on specimens with dimension of several mm. For all three material types, AE activity set at 2% strain. Differences in AE behaviour of the three materials was proven based on AE hitrate, signal peak amplitudes as well as weighted peak frequencies (WPF). Future work focuses on combination of AE and SX-µCT aiming for more detailed knowledge on damage mechanism of metal matrix composites.
T2 - Schall21
CY - Online meeting
DA - 24.02.2021
KW - AlSi12CuMgNi
KW - Al-Si alloys
KW - Acoustic emission
KW - Tension
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534268
UR - https://www.dgzfp.de/seminar/schall21
AN - OPUS4-53426
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Auswirkungen von vereinheitlichten Prozeduren auf tribologische Versuche
N2 - Anerkannte Institutionen stellen ihre kombinierten Kompetenzen auf dem Gebiet tribologischer Charakterisierungen Industrie und Forschung zur Verfügung (https://www.i-tribomat.eu/). Ein Aspekt hierbei ist eine tribologische Datenbank. Um die nötige Qualität der Daten sicherzustellen, sind vereinheitlichte Prozeduren erforderlich, in deren Auswirkungen dieser Vortrag einen Einblick gibt.
T2 - 62. Tribologie-Fachtagung der Gesellschaft für Tribologie e. V.
CY - Online meeting
DA - 28.09.2021
KW - Datenbank
KW - Tribologische Daten
KW - Europäisches Tribologie-Zentrum
PY - 2021
AN - OPUS4-53429
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
A1 - Grundtner, R.
A1 - Pagano, F.
A1 - Nyberg, E.
A1 - Heino, V.
A1 - Spaltmann, Dirk
A1 - Gradt, Thomas
T1 - Auswirkungen von vereinheitlichten Prozeduren auf tribologische Versuche
N2 - Anerkannte Institutionen stellen ihre Kompetenzen auf dem Gebiet tribologischer Charakterisierungen Industrie und Forschung zur Verfügung (https://www.i-tribomat.eu/). Ein Aspekt hierbei ist eine tribologische Datenbank. Um die nötige Qualität der Daten sicherzustellen, sind vereinheitlichte Prozeduren erforderlich, in deren Auswirkungen dieser Vortrag einen Einblick gibt.
T2 - 62. Tribologie-Fachtagung der Gesellschaft für Tribologie e. V.
CY - Online meeting
DA - 27.09.2021
KW - Datenbank
KW - Tribologische Daten
KW - Europäisches Tribologie-Zentrum
PY - 2021
SN - 978-3-9817451-6-0
VL - 15
SP - 15/1
EP - 15/4
AN - OPUS4-53430
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
A1 - Le, Quynh-Hoa
T1 - Entwicklung einer fraktographischen Symbolik
N2 - Bei der Untersuchung von Bruchflächen werden zunächst Beobachtungen gemacht, d.h. makroskopische und mikroskopische Merkmale analysiert und in Bildern dokumentiert. Im zweiten Schritt werden anhand der gefundenen Merkmale Rissverlauf und Bruchmechanismen ermittelt. Abschließend sollen diese Ergebnisse in einem Bericht oder Gutachten zusammengefasst werden. Hierbei ist eine skizzenhafte Darstellung der fraktographischen Befunde hilfreich für das Verständnis des Lesers. Ein vorgefertigter fraktographischer Symbolsatz würde dies erheblich vereinfachen.
Skizzen von fraktographischen Befunden sind in der Literatur recht häufig zu finden, z.B. in der VDI 3822 oder dem ASM Handbook Fractography, allerdings gibt es hierzu keine umfassende Systematik, wie sie z.B. aus der Meteorologie (Wetterkarten), Geographie (Landkarten, Seekarten) oder Geologie (Bodenkarten) seit langer Zeit bekannt sind. Deshalb wird hier der Versuch unternommen, einen Symbolsatz zu entwickeln und zur Verfügung zu stellen, mit dessen Hilfe fraktographische Befunde in eindeutiger und übersichtlicher Weise veranschaulicht werden können. Der fraktographische Symbolsatz ("Fracto Graphics") befindet sich in Entwicklung, ist offen zur Diskussion sowie für Verbesserungen.
T2 - 55. Metallographie-Tagung
CY - Online meeting
DA - 29.9.2021
KW - Fraktographie
KW - Symbolik
KW - Schadensanalyse
PY - 2021
AN - OPUS4-53433
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
T1 - Der Verformungswiderstand im Holz und die Rolle der Holzstrahlen
N2 - Von den Zellulosefibrillen über die Zellwand und die Anordnung der Früh- und Spätholzzellen in einem Jahrring bis hin zum Balken von Natur aus ist Holz ein optimierter Hochleistungswerkstoff, der Handwerker, Architekten, Ingenieure und Wissenschaftler fasziniert und begeistert. Im digitalen Zeitalter werden neben Standard-Laborexperimenten zunehmend Modelle und Simulationen eingesetzt, um das Verhalten des Materials unter verschiedenen Belastungen besser zu verstehen und vorherzusagen. Dazu werden Zahlenwerte von Verformungen im subzellulären Maßstab benötigt, die nun in Experimenten an der TOMCAT-Beamline (TOmographic Microscopy and Coherent rAdiology ExperimenTs) der SLS (Swiss Light Source) gewonnen werden konnten: Holzproben aus Fichte ( Picea abies Karst.) mit einem Prüfquerschnitt von mindestens 1 mm² auf Zug oder Druck beansprucht. Die strukturellen Veränderungen auf Zellebene wurden mittels Computertomographie erfasst. Für die nachträgliche Analyse der 3D-Mikrostruktur von Holz wurde ein Ansatz entwickelt, der es ermöglicht, einzelne Zellen, die in mehreren Tomogrammen unterschiedlicher Belastungszustände erfasst wurden, zu verfolgen. Dabei wurden die Zellgeometrien und das subzelluläre Deformationsverhalten quantifiziert. Unter Zugbelastung beispielsweise verengt sich die Zellwanddicke um ca. 0,8%, das sind bei der gemessenen mittleren Zellwanddicke von 3,5 µm ca. 28 nm. Diese und andere Erkenntnisse liefern nun einen direkten numerischen Zusammenhang zwischen Verformungen der Holzmikrostruktur und dem daraus resultierenden makroskopischen Verhalten.
T2 - 5. Holzanatomisches Kolloquium
CY - Dresden, Germany
DA - 09.09.2021
KW - Holz
KW - Wood materials
KW - Individual cell tracking
KW - Mikro CT
PY - 2021
AN - OPUS4-53403
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Florian, Camilo
A1 - Deziel, J.-L.
A1 - Kirner, Sabrina V.
A1 - Siegel, J.
A1 - Bonse, Jörn
T1 - Femtosecond laser-induced oxidation in the formation of periodic surface structures
N2 - Micro- and nanostructuring with laser-induced periodic surface structures (LIPSS) has been demonstrated to be feasible in a wide variety of materials including metals, semiconductors and dielectrics. Suitable processing regimes for flat, curved and complex surfaces have been identified for many materials, allowing the generation of diverse applications in fields such as optics, tribology and medicine, to name a few. A common side effect when producing such structures in air environment is the formation of a thin surface oxide layer in the laser irradiated areas. Previous studies have shown that oxidation plays an important role in the tribological performance for which the structures where created, and very recently it has been shown that the laser-induced oxide graded layers may contribute to the formation of a new type of embedded low-spatial frequency LIPSS (LSFL) with annomalous orientation parallel to the laser polarization, in addition to the appearance of the well-known high-spatial frequency LIPSS (HSFL) at the surface. In this contribution, we explore this effect experimentally for chromium nitride (CrN) irradiated with femtosecond laser pulses and compare the findings to finite-difference time-domain (FDTD) simulations of the intensity distributions at different depth positions.
T2 - 2021 Conference on Lasers and Electro-Optics/Europe – European Quantum Electronics Virtual Conferences
CY - Munich, Germany
DA - 21.06.2021
KW - Femtosecond laser ablation
KW - Finite-difference time-domain calculations
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface oxidation
PY - 2021
SN - 978-1-6654-1876-8
DO - https://doi.org/10.1109/CLEO/Europe-EQEC52157.2021.9542774
VL - 2021
SP - 1
PB - Institute of Electrical and Electronics Engineers (IEEE)
CY - Piscataway, NJ, USA
AN - OPUS4-53457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
A1 - Sanabria, S.
T1 - Der Verformungswiderstand im Holz und die Rolle der Holzstrahlen
N2 - Von den Zellulosefibrillen über die Zellwand und die Anordnung der Früh- und Spätholzzellen in einem Jahrring bis hin zum Balken von Natur aus ist Holz ein optimierter Hochleistungswerkstoff, der Handwerker, Architekten, Ingenieure und Wissenschaftler fasziniert und begeistert. Im digitalen Zeitalter werden neben Standard-Laborexperimenten zunehmend Modelle und Simulationen eingesetzt, um das Verhalten des Materials unter verschiedenen Belastungen besser zu verstehen und vorherzusagen. Dazu werden Zahlenwerte von Verformungen im subzellulären Maßstab benötigt, die nun in Experimenten an der TOMCAT-Beamline (TOmographic Microscopy and Coherent rAdiology ExperimenTs) der SLS (Swiss Light Source) gewonnen werden konnten: Holzproben aus Fichte ( Picea abies Karst.) mit einem Prüfquerschnitt von mindestens 1 mm² auf Zug oder Druck beansprucht. Die strukturellen Veränderungen auf Zellebene wurden mittels Computertomographie erfasst. Für die nachträgliche Analyse der 3D-Mikrostruktur von Holz wurde ein Ansatz entwickelt, der es ermöglicht, einzelne Zellen, die in mehreren Tomogrammen unterschiedlicher Belastungszustände erfasst wurden, zu verfolgen. Dabei wurden die Zellgeometrien und das subzelluläre Deformationsverhalten quantifiziert. Unter Zugbelastung beispielsweise verengt sich die Zellwanddicke um ca. 0,8%, das sind bei der gemessenen mittleren Zellwanddicke von 3,5 µm ca. 28 nm. Diese und andere Erkenntnisse liefern nun einen direkten numerischen Zusammenhang zwischen Verformungen der Holzmikrostruktur und dem daraus resultierenden makroskopischen Verhalten.
T2 - 5. Holzanatomisches Kolloquium
CY - Dresden, Germany
DA - 09.09.2021
KW - Wood materials
KW - Holz
KW - Individual cell tracking
KW - Mikro CT
PY - 2021
SP - 92
EP - 101
CY - Dresden
AN - OPUS4-53405
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolbe, M.
A1 - Theil, Benjamin
A1 - Göder, R.
T1 - Untersuchungen zur Explosivbearbeitung von Bauteilen in Schiffsmotoren
N2 - Eine besondere angewandte Fertigungstechnik stellt die Explosivumformung dar. Deren Grundlagen vom Detonationsvorgang, der Energieübertragung und -umsetzung sowie des Werkstoffverhaltens werden beschrieben. Aufgezeigt werden Vorteile des Explosivplattierens von Metallen und Bauteilen gegenüber anderen Fertigungsverfahren und deren Anwendung insbesondere für Motorenbauteile.
KW - Schiffsmotorbauteile
KW - Explosivbearbeitung (Plattieren, Härten)
PY - 2021
SN - 0941-4584
SP - 35
EP - 43
AN - OPUS4-53078
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cappella, Brunero
A1 - Reichelt, Manuel
T1 - Origin of lognormal distribution of wear coefficient values
N2 - Wear test results exhibit often large scattering. Hence, the study of spreading of experimental results requires big datasets.
In various studies, wear coefficients were found to have lognormal distributions. Therefore, it was supposed that the wear coefficient is affected by two normally distributed variables, which combine through a product.
In the present study, we demonstrate that a lognormal distribution may arise from a nonconstant wear coefficient, too, i.e., when a system does not follow Archard’s law.
KW - Wear
KW - Archard's law
KW - Statistical distributions
KW - Spreading
PY - 2021
DO - https://doi.org/10.1016/j.triboint.2021.107207
SN - 0301-679X
VL - 164
PB - Elsevier Ltd.
AN - OPUS4-53100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Investigation of the thermal and tribological performance of localized laser dispersed tool surfaces under hot stamping conditions
N2 - In the automotive industry, hot stamping has been established as a key technology for manufacturing safety-relevant car body components with high strength-to-weight ratio. However, hot stamping tools are stressed by cyclic thermo-mechanical loads, which leads to severe wear and high friction during the forming operation. Consequently, the quality of the parts, the durability of the tools and the efficiency of the process are negatively affected. Within the scope of this work, a promising approach named laser implantation process has been investigated for improving the tribological behavior of hot stamping tools. This technique enables the fabrication of highly wear resistant, separated and elevated micro-features by embedding hard ceramic particles into the tool via pulsed laser radiation. Hence, highly stressed tool areas can be modified, which influences the thermal and tribological interactions at the blank-die interface. To clarify these cause-effect relations, numerical simulations, quenching tests as well as tribological investigations have been conducted. In this context, laser-implanted tools reveal a significantly improved tribological performance while offering the possibility to adjust the thermal properties within hot stamping. Based on these results, a tailored tool modification can be pursued in future research work, in order to enhance the effectiveness of hot stamping tooling systems.
KW - Hot stamping
KW - Laser Implantation
KW - Surface structuring
KW - Wear
KW - Friction
PY - 2021
DO - https://doi.org/10.1016/j.wear.2021.203694
VL - 476
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-52988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
A1 - Baier, Jennifa
A1 - Fischer, Daniel
A1 - Griepentrog, Michael
A1 - Hertwig, Andreas
A1 - Hielscher-Hofinger, Stefan
A1 - Stockmann, Jörg Manfred
A1 - Weise, Matthias
T1 - Mapping und Imaging modifizierter Oberflächen: Generische Kenngrößen, Fehlstellen, Reinigungszustand und Haftfestigkeit
N2 - Der Vortrag widmet sich dem Mapping und Imaging modifizierter Oberflächen: generische Kenngrößen, Fehlstellen, Reinigungszustand und Haftfestigkeit. Es werden Untersuchungsmethoden zu ihrer Prüfung dargestellt.
T2 - 37. ak-adp 2021
CY - Jena, Germany
DA - 16.06.2021
KW - Qualitätssicherung
KW - Mapping modifizierter Oberflächen
KW - Imaging modifizierter Oberflächen
KW - Generische Kenngrößen
KW - Haftfestigkeit
KW - Klebfestigkeit
PY - 2021
SP - 1
EP - 10
AN - OPUS4-52893
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Proposal for revision of en 15870 „Adhesives determination of tensile strength of butt joints”
N2 - The paper addresses the PROPOSAL FOR REVISION OF EN 15870
„ADHESIVES -DETERMINATION OF TENSILE STRENGTH OF BUTT JOINTS” “ and the follow points are discussed in more detail: Adhesives-Determination of tensile strength of butt joints, Introduction of Centrifugal Adhesion Testing, Comparison of Testing Methods.
T2 - CEN TC 193 Madrid
CY - Online meeting
DA - 04.03.2021
KW - Centrifugal Adhesion Testing (CAT)
KW - DIN EN ISO/IEC 17025
KW - Adhesives - Determination
PY - 2021
AN - OPUS4-52900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Firdous, R.
A1 - Kruschwitz, Sabine
A1 - Stephan, D.
T1 - Sequential learning to accelerate discovery of alkali-activated binders
N2 - Alkali-activated binders (AAB) can provide a clean alternative to conventional cement in terms of CO2 emissions. However, as yet there are no sufficiently accurate material models to effectively predict the AAB properties, thus making optimal mix design highly costly and reducing the attractiveness of such binders. This work adopts sequential learning (SL) in high-dimensional material spaces (consisting of composition and processing data) to find AABs that exhibit desired properties. The SL approach combines machine learning models and feedback from real experiments. For this purpose, 131 data points were collected from different publications. The data sources are described in detail, and the differences between the binders are discussed. The sought-after target property is the compressive strength of the binders after 28 days. The success is benchmarked in terms of the number of experiments required to find materials with the desired strength. The influence of some constraints was systematically analyzed, e.g., the possibility to parallelize the experiments, the influence of the chosen algorithm and the size of the training data set. The results show the advantage of SL, i.e., the amount of data required can potentially be reduced by at least one order of magnitude compared to traditional machine learning models, while at the same time exploiting highly complex information. This brings applications in laboratory practice within reach.
KW - Alkali-activated binders
KW - Machine learning
KW - Sequential learning
KW - Materials by design
KW - Materials informatics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531376
DO - https://doi.org/10.1007/s10853-021-06324-z
SN - 0022-2461
SN - 1573-4803
VL - 56
SP - 15859
EP - 15881
PB - Springer
CY - Dordrecht
AN - OPUS4-53137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Wolf, Marcus
A1 - Kranzmann, Axel
T1 - Corrosion and corrosion fatigue of steels in downhole CCS environment - A summary
N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO₃ and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO₂: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
KW - Steel
KW - High alloyed steel
KW - Corrosion
KW - Corrosion fatigue
KW - Carbon capture and storage
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531391
DO - https://doi.org/10.3390/pr9040594
SN - 2227-9717
VL - 9
IS - 4
SP - 1
EP - 33
PB - MDPI
CY - Basel
AN - OPUS4-53139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pfennig, Anja
A1 - Kranzmann, Axel
T1 - Effects of saline aquifer water on the corrosion behaviour of martensitic stainless steels during exposure to CO2 environment
N2 - Immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 and X5CrNiCuNb16-4 at T=60 °C and ambient pressure and p=100 bar were performed for 700 h - 8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS-sites in the Northern-German-Basin. Main corrosion products are FeCO₃ and FeOOH. Highest surface corrosion rates at ambient pressure are 0.8 mm/year for 42CrMo4 and lowest 0.01 mm/year for X5CrNiCuNb16-4. Corrosion rates at 100 bar (max. 0.01 mm/year for 42CrMo4, X20Cr13, X46Cr13) are generally lower than at ambient pressure (<0.01 mm/year for X35CrMo4, X5CrNiCuNb16-4). Heat treatment to martensitic microstructure offers good corrosion resistance.
T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15
CY - Abu Dhabi, United Arab Emirates
DA - 15.03.2021
KW - CCS
KW - Corrosion
KW - High alloyed steels
PY - 2021
DO - https://doi.org/10.2139/ssrn.3812248
SP - 1
EP - 12
PB - SSRN
CY - Rochester, NY
AN - OPUS4-53140
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pfennig, Anja
A1 - Wolf, Marcus
A1 - Kranzmann, Axel
T1 - Evaluating corrosion and corrosion fatigue behavior via laboratory testing techniques in highly corrosive CCS-environment
N2 - In CCS environment (carbon capture and storage) pipes are loaded statically and/or cyclically and at the same time exposed constantly to the highly corrosive hot thermal water. Experimental procedures such as ambient pressure immersions tests, in-situ corrosion fatigue experiments using a flexibly designed corrosion chamber at ambient pressure and a specially designed corrosion chamber at high pressure. Experimental set-ups for push/pull and rotation bending load are introduced. The corrosion behavior and lifetime reduction of high alloyed steels (X46Cr13, 1.4043), (X5CrNiCuNb16-4, 1.4542) and (X2CrNiMoN22-5-3, 1.4462) is demonstrated (T=60 °C, geothermal brine: Stuttgart Aquifer flow rate: 9 l/h, CO₂).
T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15
CY - Abu Dhabi, United Arab Emirates
DA - 15.03.2021
KW - Steel
KW - Supercritical CO2
KW - Pipeline
KW - Corrosion
KW - CO2-storage
PY - 2021
DO - https://doi.org/10.2139/ssrn.3812193
SP - 1
EP - 11
PB - SSRN
CY - Rochester, NY
AN - OPUS4-53142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wagner, Adrian
T1 - Auslagerung von nichtrostenden Stählen in Straßentunneln - Stand nach 3 Jahren
N2 - Im Sinne einer mittel- bis langfristigen Reduktion wartungsbedingter Verkehrsbeeinflussungen in Tunnelbauwerken ist es von Bedeutung, die intensiven und aufwendigen Reinigungs- und Pflegearbeiten für Ein- und Anbauteile aus nichtrostendem Stahl in Straßentunneln zu reduzieren. Unter diesem Aspekt besteht großes Interesse die Einsatzmöglichkeiten alternativer nichtrostender Stähle, zu den bislang gebräuchlichen nichtrostenden austenitischen Stählen 1.4404 und 1.4571, zu eruieren. In dem Forschungsprojekt geht es um die Qualifizierung nichtrostender ferritisch austenitischer Stähle (Duplexstahl) in Straßentunneln. Diese verfügen im Vergleich zu austenitischen Stählen über eine doppelt so hohe Festigkeit bei gleichzeitig hoher Korrosionsbeständigkeit. In dieser Präsentation werden die Auslagerungsergebnisse nach 3 Jahren vorgestellt.
T2 - Vorstellung der 3 Jahres Ergebnisse beim VDEh in Düsseldorf
CY - Düsseldorf
DA - 04.08.2021
KW - Duplex
KW - Tunnelbauwerke
KW - Korrosion
KW - Korrosivität
KW - Straßentunnel
KW - Lean-Duplex
PY - 2021
AN - OPUS4-53068
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Bala, P.
A1 - Hourahine, B.
A1 - Trager-Cowan, C.
T1 - Kikuchi pattern simulations of backscattered and transmitted electrons
N2 - We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKDcan be affected by changes in the order of 10−3–10-2 if excess-deficiency features are not considered in the theoreticalmodel underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer frombiases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model.
KW - Electron diffraction
KW - EBSD
KW - Kikuchi diffraction
KW - Pattern matching
PY - 2021
DO - https://doi.org/10.1111/jmi.13051
VL - 284
IS - 2
SP - 157
EP - 184
PB - Wiley Online Library
AN - OPUS4-53109
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Treninkov, И. A
A1 - Petrushin, N. V.
A1 - Epishin, А. I.
A1 - Svetlov, I. L.
A1 - Nolze, Gert
A1 - Elyutin, E. S.
T1 - ЭКСПЕРИМЕНТАЛЬНОЕ ОПРЕДЕЛЕНИЕ ТЕМПЕРАТУРНОЙ ЗАВИСИМОСТИ СТРУКТУРНО-ФАЗОВЫХ ПАРАМЕТРОВ НИКЕЛЕВОГО ЖАРОПРОЧНОГО СПЛАВА
T1 - Experimental determination of temperature dependence of structural-phase parameters of nickel-based superalloy
N2 - Методом рентгеноструктурного анализа в интервале температур 18—1150 °С определены температурные зависимости периодов кристаллических решеток γ- и γ'-фаз, их размерно-го несоответствия (мисфит) и объемной доли γ'-фазы экспериментального монокристал-лического жаропрочного никелевого сплава. Определены диапазоны температур, в которых происходят интенсивные изменения структурно-фазовых характеристик исследованного сплава.
KW - рентгеноструктурный анализ
KW - высокие температуры
KW - жаропрочные нике- левые сплавы
KW - монокристалл
KW - γ- и γ'-фазы, период кристаллической решетки
PY - 2021
DO - https://doi.org/10.31044/1684-579x-2021-0-7-3-12
IS - 7
SP - 3
EP - 12
AN - OPUS4-53110
LA - rus
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tokarski, T.
A1 - Nolze, Gert
A1 - Winkelmann, A.
A1 - Rychlowski, L.
A1 - Bala, P.
A1 - Cios, G.
T1 - Transmission Kikuchi diffraction: The impact of the signal-to-noise ratio
N2 - Signal optimization for transmission Kikuchi diffraction (TKD) measurements in the scanning electron microscope is investigated by a comparison of different sample holder designs. An optimized design is presented, which uses a metal shield to efficiently trap the electron beam after transmission through the sample. For comparison, a second holder configuration allows a significant number of the transmitted electrons to scatter back from the surface of the sample holder onto the diffraction camera screen. It is shown that the secondary interaction with the sample holder leads to a significant increase in the background level, as well as to additional noise in the final Kikuchi diffraction signal. The clean TKD signal of the optimized holder design with reduced background scattering makes it possible to use small signal changes in the range of 2% of the camera full dynamic range. As is shown by an analysis of the power spectrum, the signal-to-noise ratio in the processed Kikuchi diffraction patterns is improved by an order of magnitude. As a result, the optimized design allows an increase in pattern signal to noise ratio which may lead to increase in measurement speed and indexing reliability.
KW - EBSD
KW - SEM
KW - Transmission Kikuchi diffraction
KW - Sample holder
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531743
DO - https://doi.org/10.1016/j.ultramic.2021.113372
SN - 0304-3991
SN - 1879-2723
VL - 230
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wiehle, Philipp
A1 - Brinkmann, M.
T1 - Tragfähigkeit von Lehmmauerwerk - Experimentelle und numerische Analyse
T1 - Load-bearing capacity of earth masonry – An experimental and numerical analysis
N2 - Die Bemessung von tragendem Lehmmauerwerk erfolgt in Deutschland auf Basis der Lehmbau Regeln. Das dort verankerte Nachweisverfahren beruht auf einem globalen Sicherheitskonzept, welches aus zuverlässigkeitstheoretischer Sicht nicht mehr dem Stand der Technik entspricht. Auf Grund dessen wird das Bemessungskonzept für Lehmmauerwerk vom Deutschen Institut für Bautechnik (DIBt) voraussichtlich 2023 außer Kraft gesetzt. Ein statischer Nachweis von tragenden Lehmbauten wäre in Deutschland dann ausschließlich mit einer Zustimmung im Einzelfall (ZiE) oder vorhabenbezogener Bauartgenehmigung (vBg) möglich. Beides ist mit erheblichem Mehraufwand und höheren Kosten verbunden, was für den Lehmmauerwerksbau einen entscheidenden Nachteil im Vergleich zum konventionellen Mauerwerksbau darstellt. Um eine unkomplizierte Praxisanwendung von Lehmmauerwerk zu ermöglichen, werden innerhalb eines Forschungsvorhabens, welches von der Bundesanstalt für Materialforschung und -prüfung (BAM), dem Institut für Massivbau der Technischen Universität Darmstadt sowie dem Ingenieurbüro ZRS durchgeführt wird, auf Basis der Produktnormen für Lehmsteine und Lehmmauermörtel Grundlagen für ein aktualisiertes Bemessungskonzept entwickelt. Im Rahmen des Projekts wird ebenfalls untersucht, inwiefern die Bemessungsregeln nach den vereinfachten Berechnungsmethoden für unbewehrtes Mauerwerk gemäß DIN EN 1996-3 / NA auf den Lehmmauerwerksbau übertragbar sind. Falls eine Anwendung des normativen Nachweisverfahrens bei Lehmmauerwerk möglich ist, wäre zukünftig eine Aufnahme von Lehmsteinen und Lehmmauermörtel in den nationalen Anhang des Eurocode 6 denkbar, was eine bedeutsame Erweiterung des Anwendungsbereichs von Lehmmauerwerk zur Folge hätte.
Diverse wissenschaftliche Untersuchungen konnten zeigen, dass bemessungsrelevante Festigkeits- und Verformungseigenschaften von Lehmmauerwerksbaustoffen stark von der vorherrschenden Materialfeuchte abhängen, welche im hygroskopischen Wassergehaltsbereich im Wesentlichen von der relativen Luftfeuchte (RLF) bestimmt wird. Auch die Zwischenergebnisse des laufenden Forschungsvorhabens zur Entwicklung eines Bemessungskonzepts für Lehmmauerwerk ergaben eine deutlich erkennbare Abhängigkeit zwischen der Materialfeuchte und den relevanten Festigkeits- und Verformungseigenschaften. Eine detaillierte Kenntnis des feuchteabhängigen Materialverhaltens von Lehmsteinen, -mörtel und -mauerwerk ist zwingend erforderlich, um ein konsistentes und zuverlässiges Bemessungskonzept für Lehmmauerwerk zu entwickeln. Im Rahmen des laufenden Forschungsprojektes werden deshalb umfangreiche Versuche zum Drucktragverhalten von Lehmsteinen und -mörtel sowie Lehmmauerwerk nach Konditionierung bei unterschiedlichen RLF durchgeführt und analysiert. Weiterhin werden auf Basis der experimentellen Ergebnisse numerische Modelle kalibriert, welche die detaillierte Analyse der Biegedrucktragfähigkeit von Lehmmauerwerk ermöglichen.
In diesem Beitrag werden zunächst die bisherigen Zwischenergebnisse bezüglich der experimentell ermittelten feuchteabhängigen Materialkennwerte von Lehmsteinen, -mörtel und -mauerwerk dargelegt. Darauf aufbauend werden numerische Untersuchungen zur Bestimmung der Systemtragfähigkeit von Lehmmauerwerk unter Feuchteeinflusses durchgeführt und erläutert.
N2 - The structural design of load-bearing earthen masonry in Germany is based on the Lehmbau Regeln. The verification procedure outlined in these regulations is based on a global safety concept that no longer corresponds to the state of the art from a reliability theory perspective. As a result, the structural design concept for earthen masonry will most likely be discontinued by the German Institute for Building Technology (DIBt) in 2023. A structural verification of load-bearing earthen buildings would then only be possible in Germany with an approval for individual cases (ZiE) or a project-related permit type (vBg). Both methods are associated with considerable additional work and higher costs, which is a decisive disadvantage for earthen masonry construction compared to conventional masonry construction. In order to enable a straightforward practical application of earthen masonry, the Federal Institute for Materials Research and Testing (BAM), the Institute for Solid Construction of the Technical University of Darmstadt and ZRS Engineers are laying the groundwork for an updated structural design concept based on the product standards for earth blocks and earthen masonry mortar. The project will also investigate the extent to which the design rules based on the simplified calculation methods for unreinforced masonry according to DIN EN 1996-3 / NA can be transferred to earthen masonry construction. If the normative verification procedure can be applied to earthen masonry, it would be conceivable to include earth blocks and earthen masonry mortar in the national appendix of Eurocode 6 in the future, which would result in a significant expansion of the field of application of earthen masonry.
Various scientific studies have shown that the strength and deformation properties of earthen masonry building materials relevant to structural design are strongly dependent on the prevailing material moisture level, which is essentially determined by the relative humidity (RH) in the hygroscopic water content range. The interim results of the current research project for the development of a structural design concept for earthen masonry also showed a clearly recognisable dependency between the material moisture level and the relevant strength and deformation properties. Detailed knowledge of the moisture-dependent material behaviour of earth blocks, earthen mortar and masonry is absolutely essential to developing a consistent and reliable structural design concept for earthen masonry. Within the framework of the current research project, extensive tests on the pressure load bearing capacity of earth blocks and earthen mortar as well as earthen masonry after conditioning at different RH levels are therefore being carried out and analysed. Furthermore, numerical models are being calibrated on the basis of the experiment results, which facilitate a detailed analysis of the bending pressure bearing capacity of earthen masonry.
This paper presents, firstly, the interim results obtained so far concerning the experimentally determined moisture-dependent material characteristics of earth blocks, earthen mortar and masonry. Based on this material, numerical investigations for determining the system bearing capacity of earthen masonry under the influence of moisture are carried out and explained.
T2 - LEHM 2020
CY - Weimar, Germany
DA - 30.10.2020
KW - Lehm
KW - Earth
KW - Tragfähigkeit
KW - Mauerwerk
KW - Feuchte
KW - Load-bearing
KW - Moisture
KW - Strength
PY - 2020
SP - 1
EP - 12
PB - Dachverband Lehm
CY - Weimar
AN - OPUS4-53231
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Undesired X-ray emission during ultrashort pulse laser material processing
N2 - The use of ultrashort laser pulses for material processing in air has many advantages. Due to the progressive development in the laser sector, average powers in the kW range with pulse repetition rates exceeding the MHz-level are available. The machining with high-intensity laser pulses can be accompanied by the generation of a near-surface electron plasma due to absorption and ionization of the material, a subsequent plasma heating by the laser pulse, and finally an interaction of “hot” plasma electrons with the workpiece leading to continuous and characteristic X-ray radiation. The amount of this unwanted X-ray radiation is determined by the laser parameters (pulse duration, intensity, wavelength, polarization), the workpiece (atomic number, surface preparation), and the laser process management (scanning or stationary regime, laser turning). The use of laser intensities above 10^13 W/cm^2 in combination with laser pulse repetition rates in the few 100 kHz-range can lead to X-ray dose rates exceeding the permitted X-ray limits for members of the public. Especially the materials tungsten and steel show significant X-ray emission. Recently, the current state of the art in the field of undesired generation of X-ray radiation during ultrashort pulse laser processing in air was reviewed. In this presentation, important aspects of the measured X-ray doses, X-ray spectra, and practical issues of radiation protection are discussed.
T2 - 28th International Conference on Advanced Laser Technologies (ALT'21)
CY - Online meeting
DA - 06.09.2021
KW - Ultrashort laser pulses
KW - Material processing
KW - X-ray emission
KW - Radiation protection
PY - 2021
AN - OPUS4-53241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Scattering is a powerful tool to follow nucleation and growth of minerals from solutions
N2 - In recent years, we have come to appreciate the astounding intricacy of the formation process of minerals from ions in aqueous solutions. The original ‘textbook’ image o these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species [e.g. 1], including solute clusters (e.g. prenucleation clusters PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc. In general, these precursor or intermediate species constitute different, often short-lived points along the pathway from dissolved ions to the final solids (typically crystals in this context). In this regard synchrotron-based scattering (SAXS/WAXS/HEXD appears to be the perfect tool to follow in situ and in a time-resolved manner the crystallization pathways because of the temporal and spatial length scales that can be directly accessed with these techniques.
Here, I show how we used scattering to probe the crystallization mechanisms o calcium sulfate. CaSO4 minerals (i.e. gypsum, anhydrite and bassanite) are widespread in natural and industrial environments. During the last several years, a number o studies have revealed indeed that nucleation in the CaSO4-H2O system is non-classical My SAXS data demonstrate that gypsum precipitation, involves formation and aggregation of sub-3 nm primary species. These species constitute building blocks o an amorphous precursor phase [2]. Further, I show how in situ high-energy X-ray diffraction experiments and molecular dynamics (MD) simulations can be combined to derive the atomic structure of the primary CaSO4 clusters seen at small-angles [3]. fitted several plausible structures to the derived pair distribution functions and explored their dynamic properties using unbiased MD simulations based on polarizable force fields. Finally, based on combined SAXS/WAXS, broad-q-range measurements, show that the process of formation of bassanite, a less hydrated form of CaSO4, is very similar to the formation of gypsum: it also involves the aggregation of small primary species into larger disordered aggregates [4].
Based on these recent insights I formulated a tentative general model for calcium sulfate precipitation from solution. This model involves primary species that are formed through the assembly of multiple Ca2+ and SO42- ions into nanoclusters. These nanoclusters assemble into poorly ordered (i.e. amorphous) hydrated aggregates which in turn undergo ordering into coherent crystalline units of either gypsum o bassanite (and possibly anhydrite). Determination of the structure and (meta)stability of the primary species is important from both a fundamental, e.g. establishing a general non-classical nucleation model, and applied perspective; e.g. allow for an improved design of additives for greater control of the nucleation pathway
T2 - BAM - Abteilungsseminar 6.3
CY - Online meeting
DA - 21.02.2021
KW - Scattering
KW - SAXS/WAXS
KW - Calcium sulfate
PY - 2021
AN - OPUS4-53713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Uncertainty budgets in surface techno-logy: step height, layer thickness, indentation hardness, adehesive strength
N2 - The object (sample) and the measurement/testing procedure may always have unknown degrees of freedom, i.e. instead of 𝐯 ≥ n – 1 in many cases 𝐯 ≫ n - 1 may apply, in particular in the micro- and nano-world!
T2 - 10. VDI-Fachtagung, Messunsicherheit und Prüfprozesse
CY - Erfurt, Germany
DA - 10.11.2021
KW - Methodology in metrology
KW - Methodology in testing
KW - Spectroscopic Ellipsometry
KW - Instrumented Indentation (IIT)
KW - Centrifugal Adhesion Testing (CAT)
PY - 2021
AN - OPUS4-53739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wagner, Adrian
T1 - Korrosionsmonitoring bei der Instandsetzung von chloridbelasteten Stahlbetonwerken
N2 - In der aktuellen RL-SIB (DAfStB) wie auch in der TR Instandsetzung (DIBt) ist bei Anwendung des Instandsetzungsprinzips W-CL der Erfolg der Maßnahme durch Einbau und Messung von Korrosionsstromsensoren gefordert. Art und Aufbau der Sensoren sowie Kriterien zur Bewertung der Ergebnisse gibt es nicht.
Ziel ist die Ausarbeitung eines Regelwerks-Entwurfes für die Art und den Aufbau von Korrosionsmonitoring-Systemen sowie für Kriterien zur zuverlässigen Bewertung der Messergebnisse, mit denen der Erfolg bei verschiedenen Instandsetzungskonzepten überprüft werden kann.
T2 - 3. PA Sitzung WIPANO Projekt KoMICS
CY - Berlin, Germany
DA - 17.11.2021
KW - Korrosion
KW - Korrosionsmonitoring
KW - Sensoren
KW - Chloridhaltiger Beton
KW - Instandhaltung
PY - 2021
AN - OPUS4-53782
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wilrich, Cordula
T1 - Von Aggregatzustand bis Zündtemperatur: Physikalisch-chemische Eigenschaften in Abschnitt 9 des Sicherheitsdatenblatts
N2 - Daten und Informationen zu physikalisch-chemischen Eigenschaften und Gefahren von Stoffen und Gemischen sind im Sicherheitsdatenblatt in Abschnitt 9 anzugeben. Die Anforderungen stammen aus REACH Anhang II und sind Anfang 2021 neugefasst worden. REACH implementiert damit die Neufassung des entsprechenden Abschnitts 9 aus dem UN-GHS – mit einigen europäischen Ergänzungen.
Der Vortrag gibt einen Überblick über die Änderungen und stellt die Ergänzungen, die sich an die Ersteller von Sicherheitsdatenblättern richten, anhand einiger aussagekräftiger Beispiele vor.
T2 - Informationsveranstaltung „REACH: Aktuelles zum Sicherheitsdatenblatt - Wie, was, wann?“ der nationalen Auskunftsstelle des Bundes für REACH, CLP und Biozide (Helpdesk)
CY - Online meeting
DA - 20.01.2022
KW - Chemikalienrecht
KW - GHS
KW - Gefahrstoff
KW - Physikalische Gefahren
KW - Physikalische-chemische Eigenschaften
KW - REACH
KW - SDS
KW - Sicherheitsdatenblatt
PY - 2022
UR - https://www.reach-clp-biozid-helpdesk.de/SharedDocs/Termine/DE/2022-01-22_Aktuelles_zum_Sicherheitsdatenblatt.html
AN - OPUS4-54235
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Effects of harmonised procedures in (digital) Tribology
N2 - The talk presents the work on digitalisation in tribology and the harmonised procedures developed in i-Tribomat.
T2 - NanoMECommons workshop "Materials characterization challenges to support the industry transition in the digital era
CY - Online meeting
DA - 13.12.2021
KW - Tribology
KW - i-TRIBOMAT
KW - Characterization
KW - Digitalisation
PY - 2021
AN - OPUS4-54192
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dzekan, D.
A1 - Waske, Anja
A1 - Nielsch, K.
A1 - Fähler, S.
T1 - Efficient and affordable thermomagnetic materials for harvesting low grade waste heat
N2 - Industrial processes release substantial quantities of waste heat, which can be harvested to generate electricity. At present, the conversion of low grade waste heat to electricity relies solely on thermoelectric materials, but such materials are expensive and have low thermodynamic efficiencies. Although thermomagnetic materials may offer a promising alternative, their performance remains to be evaluated, thereby hindering their real-world application. Here, the efficiency and cost effectiveness of thermomagnetic materials are evaluated for the usage in motors, oscillators, and generators for converting waste heat to electricity. The analysis reveals that up to temperature differences of several 10 K, the best thermomagnetic materials have the potential to compete with thermoelectric materials. Importantly, it is found that the price per watt of some thermomagnetic materials is much lower compared to that of present-day thermoelectrics, which can become competitive with conventional power plants. This materials library enables the selection of the best available thermomagnetic materials for harvesting waste heat and gives guidelines for their future development.
KW - Waste heat conversion
KW - Magnetic materials
KW - Thermomagnetic generator
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541493
DO - https://doi.org/10.1063/5.0033970
VL - 9
SP - 1
EP - 9
PB - AIP Publishing
CY - Melville, USA
AN - OPUS4-54149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pfennig, Anja
T1 - How flipped classroom teaching methods in first year studying succeed
N2 - Flipping the classroom is a method to let students study on their own and then take time to discuss their questions and do extended hands-on lectures or exercises in class – or in the case of the covid-19 pandemic during plenary online sessions. First year mechanical engineering students use different teaching materials (mainly lecture videos, lightboard videos and micromodule lectures) to study from a distance and comprehend the principle underlying science in theory. Then the online plenary lectures offer the opportunity to apply their knowledge and transfer different scientific aspects of the course to get the bigger picture. Exercises, worked solutions, selfassessed tests and peer-instruction during present time help students to check on their learning progress. However, the self-study periods and (online) plenary sessions need to be guided carefully. To meet the course learning outcome and overcome the diversity of a first year class various practical leads have to be fulfilled to turn flipped classroom teaching into success.
T2 - 7th International Conference on Higher Education Advances (HEAd’21)
CY - Valencia, Spain
DA - 20.06.2021
KW - Inverted classroom
KW - Flipped classroom
KW - Online teaching
KW - Lecture videos
KW - First year students
PY - 2021
DO - https://doi.org/10.4995/HEAd21.2021.12792
SP - 1211
EP - 1219
AN - OPUS4-54156
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Wolf, M.
A1 - Kranzmann, Axel
T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary
N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/− applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
KW - Steel
KW - High alloyed steel
KW - Corrosion fatigue
KW - Cabon capture and storage
KW - CCS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541626
DO - https://doi.org/10.3390/pr9040594
VL - 9
IS - 4
SP - 594
PB - MDPI
AN - OPUS4-54162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ernst, O. C.
A1 - Böttcher, K.
A1 - Fischer, Daniel
A1 - Uebel, D.
A1 - Teubner, T.
A1 - Boeck, T.
T1 - Morphogenesis of liquid indium microdroplets on solid molybdenum surfaces during solidification at normal pressure and under vacuum conditions
N2 - Electrical and optical applications based on micro- and nanoparticles have specific demands on their interfacial properties. These properties are strongly related to atmospheric conditions to which the particles were exposed during their formation. In this study, metallic In microparticles are synthesized by solidification of In droplets on an amorphous Mo substrate at normal pressure and under vacuum conditions. The influence of ambient pressure on the interface and surface shape is investigated. While solidification at atmospheric pressure leads to collapsed particles with undisturbed contact to the substrate, low pressures result in smooth spherical particles but with cavities inside. Numerical simulations with COMSOL Multiphysics reveal different temperature profiles and heat flux in particles during solidification for both cases. This indicates different starting conditions of the solidification, which leads to the described phenomenon eventually. The investigation of the varying process conditions on the particle shape in combination with the calculated and measured temperature curves over time gives valuable insights into new approaches to synthesize micro- and nanoparticles with defined interfacial properties. Both ambient pressure and cooling rate provide well-controllable and reliable parameters for the realization of different interfacial shapes.
KW - Morphogenesis
KW - Indium
KW - Microdroplet
KW - Molybdenum
PY - 2022
DO - https://doi.org/10.1021/acs.langmuir.1c02744
SN - 0743-7463
SN - 1520-5827
VL - 38
IS - 2
SP - 762
EP - 768
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-54242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ivanov, S.
A1 - Artinov, Antoni
A1 - Zemlyakov, E.
A1 - Karpov, I.
A1 - Rylov, S.
A1 - Em, V.
T1 - Spatiotemporal Evolution of Stress Field during Direct Laser Deposition of Multilayer Thin Wall of Ti-6Al-4V
N2 - The present work seeks to extend the level of understanding of the stress field evolution during direct laser deposition (DLD) of a 3.2 mm thick multilayer wall of Ti-6Al-4V alloy by theoretical and experimental studies. The process conditions were close to the conditions used to produce large-sized structures by the DLD method, resulting in specimens having the same thermal history. A simulation procedure based on the implicit finite element method was developed for the theoretical study of the stress field evolution. The accuracy of the simulation was significantly improved by using experimentally obtained temperature-dependent mechanical properties of the DLD-processed Ti-6Al4V alloy. The residual stress field in the buildup was experimentally measured by neutron diffraction. The stress-free lattice parameter, which is decisive for the measured stresses, was determined using both a plane stress approach and a force-momentum balance. The influence of the inhomogeneity of the residual stress field on the accuracy of the experimental measurement and the validation of the simulation procedure are analyzed and discussed. Based on the numerical results it was found that the non-uniformity of the through-thickness stress distribution reaches a maximum in the central cross-section, while at the buildup ends the stresses are distributed almost uniformly. The components of the principal stresses are tensile at the buildup ends near the substrate. Furthermore, the calculated equivalent plastic strain reaches 5.9% near the buildup end, where the deposited layers are completed, while the plastic strain is practically equal to the experimentally measured ductility of the DLD-processed alloy, which is 6.2%. The experimentally measured residual stresses obtained by the force-momentum balance and the plane stress approach differ slightly from each other.
KW - Direct laser deposition
KW - Finite element simulation
KW - Neutron diffraction
KW - Residual stresses
KW - Ti-6Al-4V
KW - Mechanical properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542444
DO - https://doi.org/10.3390/ma15010263
VL - 15
IS - 263
SP - 1
EP - 20
PB - MDPI
AN - OPUS4-54244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cakir, Cafer Tufan
T1 - Unravelling the depths of complex alloys with grazing exit XANES
N2 - High entropy alloys (HEAs) are considered as a new class of alloys containing at least 5 elements with concentrations between 5 and 35 atomic percent. There has been a growing interest in HEAs in the material research field in recent years. Due to their adjustable composition, which enables the modifications of mechanical properties (such as hardness, strength and ductility etc) and their stability at high temperatures, HEAs have been the focus of various studies.
Especially the corrosion behavior of HEAs has been a wide research interest. Since the grazing exit X-ray fluorescence (GEXRF) offers a non-destructive way to collect notable information regarding the high temperature oxidation, we consider it as a useful method to investigate how HEAs behave in corrosive environments.
The main idea of grazing geometry is to enhance the fluorescence signal of the surface. This enables highly sensitive surface analyses of thin protective film on surface in sub-micrometer scale. Position-sensitive area detectors provide information regarding the signal emitted from the sample as a function of emission angle and thus allow depth-sensitive analysis. Furthermore, the data collected from samples of an incidence energy which lays within a specific energy range provides XANES data to determine oxidation states. Moreover, since GEXRF profiles can also be simulated through physical models (Urbach 1999), they enable us to determine the layer thickness of a given sample in a non-destructive way.
In this contribution, we present the preliminary results of a conceptual study regarding layer properties of CrCoNi medium entropy alloy. The successful implementation of such methodological concept will pave the way for the investigation of more complex alloys with multiple layers, which is planned for the later phases of the project.
T2 - Denver X-Ray Conference DXC 2021
CY - Online meeting
DA - 02.08.2021
KW - GEXRF
KW - High entropy alloys
KW - XANES
KW - Grazing exit
KW - XAS
PY - 2021
AN - OPUS4-54027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cakir, Cafer Tufan
T1 - Unrevealing the depths of compositionally complex alloys with grazing exit XANES
N2 - High entropy alloys (HEAs) are considered as a new class of alloys containing at least 5 elements with concentrations between 5 and 35 atomic percent. There has been a growing interest in HEAs in the material research field in recent years. Due to their adjustable composition, which enables the modifications of mechanical properties (such as hardness, strength and ductility etc) and their stability at high temperatures, HEAs have been the focus of various studies.
Especially the corrosion behavior of HEAs has been a wide research interest. Since the grazing exit X-ray fluorescence (GEXRF) offers a non-destructive way to collect notable information regarding the high temperature oxidation, we consider it as a useful method to investigate how HEAs behave in corrosive environments.
The main idea of grazing geometry is to enhance the fluorescence signal of the surface. This enables highly sensitive surface analyses of thin protective film on surface in sub-micrometer scale. Position-sensitive area detectors provide information regarding the signal emitted from the sample as a function of emission angle and thus allow depth-sensitive analysis. Furthermore, the data collected from samples of an incidence energy which lays within a specific energy range provides XANES data to determine oxidation states. Moreover, since GEXRF profiles can also be simulated through physical models (Urbach 1999), they enable us to determine the layer thickness of a given sample in a non-destructive way.
In this contribution, we present the preliminary results of a conceptual study regarding layer properties of CrCoNi medium entropy alloy. The successful implementation of such methodological concept will pave the way for the investigation of more complex alloys with multiple layers, which is planned for the later phases of the project.
T2 - XAFS 2021, The 18th International XAFS Conference
CY - Online meeting
DA - 02.08.2021
KW - GEXRF
KW - High entropy alloys
KW - XANES
KW - Grazing exit
KW - XAS
PY - 2021
AN - OPUS4-54028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krietsch, Arne
A1 - Reyes Rodriguez, M.
A1 - Kristen, A.
A1 - Kadoke, D.
A1 - Abbas, Z.
A1 - Krause, U.
T1 - Ignition temperatures and flame velocities of metallic nanomaterials
N2 - The production of materials with dimensions in the nanometre range has continued to increase in recent years. In order to ensure safety when handling these products, the hazard potential of such innovative materials must be known. While several studies have already investigated the effects of explosions (such as maximum explosion pressure and maximum pressure rise) of powders with primary particles in the nanometre range, little is known about the ignition temperatures and flame velocities. Therefore, the minimum ignition temperature (MIT) of metallic nano powders (aluminium, iron, copper and zinc) was determined experimentally in a so called Godbert-Greenwald (GG) oven. Furthermore, the flame velocities were determined in a vertical tube. In order to better classify the test results, the tested samples were characterised in detail and the lower explosion limits of the tested dust samples were determined. Values for the burning velocity of aluminium nano powders are higher compared to values of micrometre powders (from literature). While MIT of nanometre aluminium powders is within the range of micrometre samples, MIT of zinc and copper nano powders is lower than values reported in literature for respective micrometre samples.
T2 - 13th Symposium International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE)
CY - Online meeting
DA - 27.07.2021
KW - Dust explosions
KW - Nanomaterial
KW - Flame propagation
KW - Minimum ignition temperature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540930
DO - https://doi.org/10.7795/810.20200724
SP - 591
EP - 605
PB - Physikalisch-Technische Bundesanstalt
AN - OPUS4-54093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pinomaa, T.
A1 - Lindroos, M.
A1 - Jreidini, P.
A1 - Haapalehto, M.
A1 - Ammar, K.
A1 - Wang, Lei
A1 - Forest, S.
A1 - Provatas, N.
A1 - Laukkanen, A.
T1 - Multiscale analysis of crystalline defect formation in rapid solidification of pure aluminium and aluminium-copper alloys
N2 - Rapid solidification leads to unique microstructural features, where a less studied topic is the formation of various crystalline defects, including high dislocation densities, as well as gradients and splitting of the crystalline orientation. As these defects critically affect the material’s mechanical properties and performance features, it is important to understand the defect formation mechanisms, and how they depend on the solidification conditions and alloying. To illuminate the formation mechanisms of the rapid solidification induced crystalline defects, we conduct a multiscale modelling analysis consisting of bond-order potential-based molecular dynamics (MD), phase field crystal-based amplitude expansion simulations, and sequentially coupled phase field–crystal plasticity simulations. The resulting dislocation densities are quantified and compared to past experiments. The atomistic approaches (MD, PFC) can be used to calibrate continuum level crystal plasticity models, and the framework adds mechanistic insights arising from the multiscale analysis.
This article is part of the theme issue ‘Transport phenomena in complex systems (part 2)’.
KW - Rapid solidification
KW - Crystalline defects
KW - Molecular dynamics
KW - Phase field crystal
KW - Phase field method
KW - Crystal plasticity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542156
DO - https://doi.org/10.1098/rsta.2020.0319
SN - 1364-503X
VL - 380
IS - 2217
SP - 1
EP - 20
PB - Royal Society
CY - London
AN - OPUS4-54215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Kranzmann, Axel
T1 - Understanding the Anomalous Corrosion Behaviour of 17% Chromium Martensitic Stainless Steel in Laboratory CCS-Environment—A Descriptive Approach
N2 - To mitigate carbon dioxide emissions CO2 is compressed and sequestrated into deep geological layers (Carbon Capture and Storage CCS). The corrosion of injection pipe steels is induced when the metal is in contact with CO2 and at the same time the geological saline formation water. Stainless steels X35CrMo17 and X5CrNiCuNb16-4 with approximately 17% Cr show potential as injection pipes to engineer the Northern German Basin geological onshore CCS-site. Static laboratory experiments (T = 60 ◦C, p = 100 bar, 700–8000 h exposure time, aquifer water, CO2-flow rate of 9 L/h) were conducted to evaluate corrosion kinetics. The anomalous surface corrosion phenomena were found to be independent of heat treatment prior to exposure. The corrosion process is described as a function of the atmosphere and diffusion process of ionic species to explain the precipitation mechanism and better estimate the reliability of these particular steels in a downhole CCS environment.
KW - Corrosion
KW - Steel
KW - High alloyed steel
KW - Corrosion mechanism
KW - CCS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545700
DO - https://doi.org/10.3390/cleantechnol4020014
VL - 4
IS - 2
SP - 239
EP - 257
PB - MDPI
AN - OPUS4-54570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Unerwünschte Röntgenemission bei der UKP-Lasermaterialbearbeitung
N2 - Der Vortrag fasst aktuelle Aspekte zum unerwünschten Auftreten von Röntgenstrahlung bei der Ultrakurzpuls-Lasermaterialbearbeitung zusammen. Es werden Einflussparameter, Grenzwerte, Schutzmaßnahmen, Fragen der Abschirmung und rechtliche Gesichtspunkte diskutiert.
T2 - Bayerische Laserschutztage 2022
CY - Online meeting
DA - 18.01.2022
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
PY - 2022
AN - OPUS4-54259
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, J.
A1 - Farris, L.
A1 - Nolze, Gert
A1 - Reinsch, Stefan
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Thompson, S.
T1 - Microstructure evolution in Inconel 718 produced by powder bed fusion additive manufacturing
N2 - Inconel 718 is a precipitation strengthened, nickel-based super alloy of interest for the Additive Manufacturing (AM) of low volume, complex parts to reduce production time and cost compared to conventional subtractive processes. The AM process involves repeated rapid melting, solidification and reheating, which exposes the material to non-equilibrium conditions that affect elemental segregation and the subsequent formation of solidification phases, either beneficial or detrimental. These variations are difficult to characterize due to the small length scale within the micron sized melt pool. To understand how the non-equilibrium conditions affect the initial solidification phases and their critical temperatures, a multi-length scale, multi modal approach has been taken to evaluate various methods for identifying the initial phases formed in the as-built Inconel 718 produced by laser-powder bed fusion (L-PBF) additive manufacturing (AM). Using a range of characterization tools from the bulk differential thermal analysis (DTA) and x-ray diffraction (XRD) to spatially resolved images using a variety of electron microscopy tools, a better understanding is obtained of how these minor phases can be properly identified regarding the amount and size, morphology and distribution. Using the most promising characterization techniques for investigation of the as-built specimens, those techniques were used to evaluate the specimens after various heat treatments. During the sequence of heat treatments, the initial as-built dendritic structures recrystallized into well-defined grains whose size was dependent on the temperature. Although the resulting strength was similar in all heat treated specimens, the elongation increased as the grain size was refined due to differences in the precipitated phase distribution and morphology.
KW - Metal additive manufacturing
KW - Inconel 718
KW - Heat treatment
KW - Grain boundary precipitates
KW - Laves phase
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542758
DO - https://doi.org/10.3390/jmmp6010020
SN - 2504-4494
VL - 6
IS - 1
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-54275
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Tribological and thermal behavior of laser implanted tool surfaces for hot stamping AlSi coated 22MnB5 sheets
N2 - In the automotive industry, the development of electrically powered vehicles has become a major forward-looking topic. For improving the range and thus the efficiency of electric cars, lightweight construction has gained even more importance. In this regard, hot stamping has been established as a suitable and resource efficient process to manufacture high-strength and lightweight body-in-white components. This method combines hot forming and quenching of boron-manganese steel 22MnB5 in a single process step. As a result, complex structures with thin sheet thicknesses and high ultimate tensile strength up to 1500 MPa are generated. However, the use of lubricants is not possible at elevated temperatures, which subsequently leads to high thermo-mechanical tool stresses. As a side effect, high friction and severe wear occur during the forming process, which affect the resulting part quality and maximum tool life. Therefore, the aim of this study is to improve the tribological performance of hot stamping tools by using a laser implantation process. This technique is based on manufacturing highly wear resistant, separated and elevated structures in micrometer range by embedding hard ceramic particles into the tool material via pulsed laser radiation. As a result, highly stressed areas on the tool surface can be modified locally, which in turn influence the tribological and thermal behavior during the forming process. In this regard, laser implanted and conventionally tool surfaces were investigated under hot stamping conditions. A modified pin-on-disk test was used to analyze the friction coefficient and occuring wear mechanisms. Furthermore, quenching tests as well as hardness measurements were carried out to gain in-depth knowledge about the cooling behavior of the modified tool surfaces and its impact to the resulting mechanical part properties.
KW - Laser implantation
KW - Laser dispersing
KW - Surface structuring
KW - Hot stamping
PY - 2022
DO - https://doi.org/10.4028/p-e4i60t
SN - 1662-9507
IS - 414
SP - 69
EP - 74
PB - Trans Tech Publications
CY - Baech
AN - OPUS4-54302
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Trusted tribological materials characterisation services
N2 - Renowed institutions in various European countries combine their tribo-testing as well as analytical and characterisation capabilities for the European Tribology Centre. This foundation of one of the largest Open Innovative Test Beds for tribological services, the aim of the European Horizon 2020 project i-TRIBOMAT, places certain demands on the comparability of the test equipment and execution process.
T2 - 23rd International Colloquium Tribology at TAE
CY - Online meeting
DA - 25.01.2022
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Harmonisation
KW - Round robin tests
KW - Interlaboratory tests
PY - 2022
AN - OPUS4-54291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
A1 - Grundtner, R.
A1 - Newrkla, K.
A1 - Spaltmann, Dirk
A1 - Pagano, F.
A1 - Pinedo, B.
A1 - Nyberg, E.
A1 - Söderfjäll, M.
A1 - Heino, V.
A1 - Ronkainen, H.
ED - Topolovec-Miklozic, K.
ED - Pauschitz, A.
ED - Fatemi, A.
T1 - Trusted tribological materials characterisation services
N2 - Renowed institutions in various European countries combine their tribo-testing as well as analytical and characterisation capabilities for the European Tribology Centre. This foundation of one of the largest Open Innovative Test Beds for tribological services, the aim of the European Horizon 2020 project i-TRIBOMAT, places certain demands on the comparability of the test equipment and execution process.
T2 - 23rd International Colloquium Tribology at TAE
CY - Online meeting
DA - 25.01.2022
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Harmonisation
KW - Round robin tests
KW - Interlaboratory tests
PY - 2022
SN - 978-3-8169-3547-6
SP - 503
EP - 505
PB - Narr Francke Attempto Verlag
CY - Tübingen
AN - OPUS4-54293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rütters, H.
A1 - Fischer, S.
A1 - Le, Quynh Hoa
A1 - Bettge, Dirk
A1 - Bäßler, Ralph
A1 - Maßmann, J.
A1 - Ostertag-Henning, C.
A1 - Wolf, J. L.
A1 - Pumpa, M.
A1 - Lubenau, U.
A1 - Knauer, S.
A1 - Jaeger, P.
A1 - Neumann, A.
A1 - Svensson, K.
A1 - Pöllmann, H.
A1 - Lempp, C.
A1 - Menezes, F. F.
A1 - Hagemann, B.
T1 - Towards defining reasonable minimum composition thresholds – Impacts of variable CO2 stream compositions on transport, injection and storage
N2 - To set up recommendations on how to define “reasonable minimum composition thresholds” for CO2 streams to access CO2 pipeline networks, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the CCS chain. All investigations were based on a generic “CCS cluster scenario” in which CO2 streams captured from a spatial cluster of eleven emitters (seven fossil-fired power plants, two cement plants, one refinery and one steel mill) are collected in a regional pipeline network. The resulting CO2 stream (19.78 Mio t impure CO2 per year) is transported in a trunk line (onshore and offshore) and injected into five generic replicate storage structures (Buntsandstein saline aquifers) offshore. Experimental investigations and modeling of selected impacts revealed beneficial as well as adverse impacts of different impurities and their combinations. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the considered variable compositions and mass flow rates were observed. We recommend to define minimum composition thresholds for each specific CCS project through limiting
i) the overall CO2 content,
ii) maximum contents of relevant impurities or elements,
iii) acceptable variability of concentrations of critical impurities, and defining impurity combinations to be avoided.
KW - Impurities
KW - CO2 quality
KW - Pipeline network
KW - Whole-chain CCS scenario
KW - Recommendations
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543004
DO - https://doi.org/10.1016/j.ijggc.2022.103589
SN - 1750-5836
VL - 114
SP - 1
EP - 14
PB - Elsevier
CY - New York, NY
AN - OPUS4-54300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Oesch, T.
A1 - Mielentz, Frank
A1 - Meinel, Dietmar
A1 - Spyridis, P.
T1 - Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete
N2 - Integration of fiber reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel Fiber reinforced concrete (SFRC) is the deceleration of crack growth and hence its improved sustainability.
Additional benefits are associated with its structural properties, as fibers can significantly increase the ductility and the tensile strength of concrete. In some applications it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits.
Fiber reinforcement can, however, have critical disadvantages and even hinder the Performance of concrete, since it can induce an anisotropic material behavior of the mixture if the fibers are not appropriately oriented. For a safe use of SFRC in the future, reliable non-destructive testing (NDT) methods need to be identified to assess the fibers’ orientation in hardened concrete. In this study,
ultrasonic material testing, electrical impedance testing, and X-ray computed tomography have been investigated for this purpose using specially produced samples with biased or random Fiber orientations. We demonstrate the capabilities of each of these NDT techniques for fiber orientation measurements and draw conclusions based on these results about the most promising areas for future research and development.
KW - Spectral induced polarization
KW - Steel fiber reiniforced concrete
KW - Fiber orientation
KW - Non-destructive testing
KW - Micro-computed tomography
KW - Ultrasound
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543520
DO - https://doi.org/10.3390/app12020697
VL - 12
IS - 2
SP - 1
EP - 14
PB - MDPI
CY - Basel Switzerland
AN - OPUS4-54352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - 3D imaging and residual stress analysis of AM materials at BAM
N2 - The overview of the activity of group 8.5 Micro-NDT (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The research of our group is focused on the 3D imaging of AM materials by means of X-ray Computed Tomography at the lab and at synchrotron, and the residual stress characterization by diffraction (nondestructive technique).
T2 - Seminar at Chalmers University and Centre for Additive Manufacture (CAM2)
CY - Gothenburg, Sweden
DA - 19.05.2022
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Residual stress
KW - Computed tomography
KW - Synchrotron X-ray diffraction
KW - X-ray refraction
PY - 2022
AN - OPUS4-55019
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Müller, Anja
T1 - Determination of the actual morphology of core-shell nanoparticles by advanced X-ray analytical techniques: A necessity for targeted and safe nanotechnology
N2 - Even though we often do not knowingly recognize them, nanoparticles are present these days in most areas of our daily life, including food and its packaging, medicine, pharmaceuticals, cosmetics, pigments as well as electronic products, such as computer screens. The majority of these particles exhibits a core-shell morphology either intendedly or unintendedly. For the purpose of practicability, this core-shell nanoparticle (CSNP) morphology is often assumed to be ideal, namely a spherical core fully encapsulated by a shell of homogeneous thickness with a sharp interface between core and shell material. It is furthermore widely presumed that all nanoparticles in the sample possess the same shell thickness. As a matter of fact, most real CSNPs deviate in several ways from this ideal model with quite often severe impact on how efficiently they perform in a specific application.
The topic of this cumulative PhD thesis is the accurate characterization of the actual morphology of CSNPs by advanced X-ray analytical techniques, namely X-ray photoelectron spectroscopy (XPS) and scanning transmission X-ray microscopy (STXM). A special focus is on CSNPs which deviate from an ideal core-shell morphology. In the paper from 2019 nanoparticle shell thicknesses are extracted from the elastic-peak intensities in an XPS spectrum based on an ideal particle morphology. This happens for a series of CSNP samples comprising a poly(tetrafluoroethylene) (PTFE) core and either a poly(methyl methacrylate) (PMMA) or polystyrene (PS) shell. The same paper as well as the paper from 2020 demonstrate for the first time, that the analysis of the inelastic background in an XPS spectrum of CSNPs can identify and quantify the heterogeneity of the shell and the incomplete encapsulation of the core.
The result from an XPS experiment is always an average across a large nanoparticle ensemble. Deviations from an ideal morphology within a single particle of the sample cannot be assessed separately. As opposed to that, a spatial resolution of 35 nm enables STXM to visualize the interior of single CSNPs which exhibit a sufficient X-ray absorption contrast between core and shell material. In the paper from 2018 a STXM analysis is demonstrated based on the example of the PTFE-PS CSNP samples already mentioned in the previous paragraph.
In the publication from 2021 (Ca/Sr)F₂ core-shell like nanoparticle ensembles for the practical use in, among others, antireflective coatings are investigated. These nanoparticles do not possess a sharp interface between core and shell material, which is why a shell thickness determination as described in the second paragraph is inappropriate. Instead, in-depth profiles of the chemical composition are obtained by XPS experiments based on synchrotron radiation with variable X-ray photon energy to elucidate the internal morphology of the particles. Additionally, theoretical in-depth profiles of Ca and Sr XPS peak intensities are simulated, in order to facilitate the interpretation of the experiments. Thus, an enrichment of CaF₂ at the particle surface was determined, which could hardly have been assessed by any other analytical technique. Because this kind of non-destructive depth profiling by XPS is very demanding, more than usual effort is spent on gapless documentation of the experiments to ensure full reproducibility.
Due to the vast diversity of nanoparticles differing in material, composition and shape, a measurement procedure cannot unalteredly be transferred from one sample to another. Nevertheless, because the papers in this thesis present a greater depth of reporting on the experiments than comparable publications, they constitute an important guidance for other scientists on how to obtain meaningful information about CSNPs from surface analysis.
N2 - Obwohl wir sie oft nicht bewusst wahrnehmen, sind Nanopartikel heutzutage in den meisten Bereichen unseres Alltags präsent, unter anderem in Lebensmitteln und ihren Verpackungen, Medizin, Medikamenten, Kosmetik, Pigmenten und in elektronischen Geräten wie Computermonitoren. Ein Großteil dieser Partikel weist, beabsichtigt oder unbeabsichtigt, eine Kern-Schale Morphologie auf. Einfachheitshalber wird diese Morphologie eines Kern-Schale-Nanopartikels (CSNP) oft als ideal angenommen, d.h. als ein sphärischer Kern, der komplett von einer Schale homogener Dicke bedeckt ist, mit einer scharfen Grenzfläche zwischen Kern- und Schalenmaterial. Außerdem wird vielfach auch davon ausgegangen, alle Partikel der Probe hätten gleiche Schalendicken. Tatsächlich weichen die meisten realen CSNPs in verschiedenster Weise von diesem Idealmodell ab, mit oft drastischen Auswirkungen darauf, wie gut sie ihre Aufgabe in einer bestimmten Anwendung erfüllen.
Das Thema dieser kumulativen Doktorarbeit ist die exakte Charakterisierung der wirklichen Morphologie von CSNPs mit modernen Röntgen-basierten Methoden, konkret Röntgen-Photoelektronen-Spektroskopie (XPS) und Raster-Transmissions-Röntgen-Mikroskopie (STXM). Der Fokus liegt insbesondere auf CSNPs, die von einer idealen Kern-Schale-Morphologie abweichen. Im Artikel von 2019 werden Schalendicken von Nanopartikeln aus den elastischen Peakintensitäten im XPS-Spektrum unter Annahme einer idealen Partikelmorphologie abgeleitet. Dies geschieht für eine Reihe von CSNP-Proben, welche aus einem Polytetrafluoroethylen- (PTFE) Kern und entweder einer Polymethylmethacrylat- (PMMA) oder Polystyrol- (PS) Schale bestehen. Sowohl dieser Artikel als auch der von 2020 zeigen erstmals, dass die Auswertung des inelastischen Untergrunds eines CSNP-XPS-Spektrums in der Lage ist, die Heterogenität der Schale und die unvollständige Ummantelung des Kerns zu identifizieren und zu quantifizieren.
Das Ergebnis eines XPS-Experiments ist immer ein Mittelwert über ein großes Nanopartikelensemble. Inwiefern ein einzelner Partikel innerhalb der Probe von einer idealen Morphologie abweicht, kann nicht gesondert erfasst werden. Im Gegensatz dazu kann STXM mit einer räumlichen Auflösung von 35 nm das Innere einzelner CSNPs visualisieren, sofern sie genügend Röntgenabsorptionskontrast zwischen Kern- und Schalenmaterial aufweisen. Im Artikel von 2018 wird am Beispiel der bereits im vorherigen Abschnitt genannt PTFE-PS-CSNPProben eine solche STXM-Untersuchung demonstriert.
In der Veröffentlichung von 2021 werden Kern-Schale-artige (Ca/Sr)F₂-Nanopartikel für den praktischen Einsatz in unter anderem entspiegelnden Beschichtungen untersucht. Da hier keine scharfe Grenzfläche zwischen Kern- und Schalenmaterial vorliegt, ist eine Schalendickenbestimmung, wie sie im zweiten Abschnitt diskutiert wird, nicht sinnvoll. Stattdessen werden mit Hilfe von XPS, angeregt mit Synchrotronstrahlung bei variabler Röntgenphotonenenergie, Tiefenprofile der chemischen Zusammensetzung generiert, um die innere Morphologie der Partikel aufzuklären. Zusätzlich werden theoretische Tiefenprofile der Ca- und Sr-XPS-Peakintensitäten simuliert, um die Interpretation der Experimente zu erleichtern. So wurde eine CaF₂-Anreicherung an der Oberfläche der Partikel festgestellt, die kaum mit einer anderen analytischen Methode hätte entdeckt werden können. Da diese zerstörungsfreie Bestimmung von XPS-Tiefenprofilen sehr anspruchsvoll ist, wird noch mehr als üblich auf die lückenlose Dokumentation des Experiments geachtet, um vollständige Reproduzierbarkeit zu gewährleisten.
Aufgrund der enormen Vielfalt an CSNPs, die sich in Material, Zusammensetzung und Form unterscheiden, kann eine Messmethode nicht völlig unverändert von einer Probe auf eine andere übertragen werden. Nichtsdestotrotz, da die als Teil dieser Doktorarbeit präsentierten Artikel eine deutlich ausführlichere Beschreibung der Experimente enthalten als vergleichbare Publikationen, stellen sie eine wichtige Anleitung für andere Wissenschaftler dafür dar, wie aussagekräftige Informationen über CSNPs durch Oberflächenanalytik erhalten werden können.
KW - Core-shell nanoparticle (CSNP)
KW - X-ray photoelectron spectroscopy (XPS)
KW - Scanning transmission X-ray microscopy (STXM)
PY - 2022
DO - https://doi.org/10.18452/24312
SP - i
EP - 243
PB - Humboldt-Universität
CY - Berlin
AN - OPUS4-54991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lamoriniere, S.
A1 - Mitchell, P. J.
A1 - Ho, K.
A1 - Kalinka, Gerhard
A1 - Shaffer, M. S. P.
A1 - Bismarck, A.
T1 - Carbon nanotube enhanced carbon Fibre-Poly(ether ether ketone) interfaces in model hierarchical composites
N2 - Poly (ether ether ketone) (PEEK) has a high continuous service temperature, excellent mechanical properties, and good solvent and abrasion resistance, which can be further improved through the addition of carbon nanotubes (CNTs). CNT-PEEK nanocomposites are promising matrices for continuous carbon fibre composites; powder processing can mitigate the high melt viscosities in these systems. In this study, model single fibre (hierarchical) composites were produced by embedding sized and desized carbon fibres in nanocomposite CNTPEEK powders followed by single fibre pull-out tests to assess interfacial characteristics. Carbon fibre-PEEK interfacial shear strength is typically 40–45 MPa. Increasing CNT loadings increased fibre-matrix interfacial shear strength linearly up to ~70 MPa at 5.0 wt%, which was attributed to the CNT-based mechanical modification of the PEEK matrix. Apparent interfacial shear strength was inversely correlated with the embedded fibre length irrespective of carbon fibre sizing or CNT loading, indicating brittle fracture of the fibre-matrix interface.
Pulled out carbon fibres were still coated with the matrix, which indicated strong adhesion at the interface in all samples, likely related to a transcrystalline region. Adhesion was, however, negatively affected by the presence of epoxy sizings. Frictional shear strength was independent of embedded fibre length and CNT content for all samples.
KW - Keywords: Poly(ether ether ketone)
KW - Carbon fibres
KW - Carbon nanotubes
KW - Interfacial strength
KW - Debonding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550052
DO - https://doi.org/10.1016/j.compscitech.2022.109327
SN - 0266-3538
VL - 221
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-55005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiehle, Philipp
A1 - Simon, Sebastian
A1 - Baier, J.
A1 - Dennin, L.
ED - Forde, M.
T1 - Influence of relative humidity on the strength and stiffness of unstabilised earth blocks and earth masonry mortar
N2 - Aim of this study is to provide information about moisture dependent material behaviour of unstabilised loadbearing earth blocks and mortars. Compressive strength and Young’s modulus were investigated after conditioning in varying relative humidity reaching from 40 % up to 95 %. The material composition and physical properties were investigated to understand the influence of relative humidity onto the mechanical properties. A normalisation of strength and stiffness by the values obtained at 23 ◦C and 50 % relative humidity reveals a linear dependence of compressive strength and Young’s modulus that is regardless of the material composition.
Thus, it is possible to describe the influence of relative humidity onto the load-bearing behaviour of unstabilised earth masonry materials in a generally valid formulation.
KW - Earth block masonry
KW - Load-bearing behaviour
KW - Compressive strength
KW - Moisture content
KW - Sorption isotherm
PY - 2022
DO - https://doi.org/10.1016/j.conbuildmat.2022.128026
SN - 0950-0618
VL - 342
IS - Part A
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-54949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Ultrakurzpulslaser induzierte Oxidschichten zur Reduktion von Reibung und Verschleiß auf Metalloberflächen
N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nano- und Mikrostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet.
T2 - Workshop "Nachhaltigkeit durch Tribologische Schichten" - Europäische Forschungsgesellschaft Dünne Schichten e.V.
CY - Karlsruhe, Germany
DA - 17.05.2022
KW - Laser-induzierte periodische Oberflächenstrukturen
KW - Reibungsreduktion
KW - Verschleißreduktion
KW - Oberflächenmodifikation
KW - Oxidation
KW - Additive
PY - 2022
AN - OPUS4-54849
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zvereva, V.V.
A1 - Asanov, I.P.
A1 - Yusenko, Kirill
A1 - Zadesenec, A.V.
A1 - Plyusnin, P.E.
A1 - Gerasimov, E.Yu.
A1 - Maksimovskiy, E.A.
A1 - Korenev, S.V.
A1 - Asanova, T.I.
T1 - Local atomic and electronic structure of Pt‑Os nanoplates and nanofbers derived from the single‑source precursor (NH4)2[Pt0.5Os0.5Cl6]
N2 - Abstract Nowadays, Pt-Os binary systems are mainly considered as catalysts and electrocatalysts, but the role of Os in these processes is still poorly understood. The electronic structure of Pt-Os nanosystems remains a few studied as well. Using bimetallic (NH4)2[Pt0.5Os0.5Cl6] as a single-source precursor for preparing Pt-Os nanoalloy through the thermal decomposition in hydrogen and inert atmospheres, the relation of morphology, atomic ordering, and electronic structure of Pt-Os nanoalloy was examined by in situ Quick XAFS, XPS, PXRD, SEM, and HRTEM techniques. Being the only variable parameter, the decomposition atmosphere was found to govern the morphology of the Pt-Os nanoalloy and change the atomic ordering (alloying extent), which involves a change in the electronic structure. In a hydrogen atmosphere, the nanofibers (NFs) (ø ~ 5–6 nm) with the atomic ordering Oscore&Pt-richshell were observed to form; in a nitrogen atmosphere, thin nanoplates (NPLs) (~ 12 nm) with the atomic architecture Os-richcore&Ptrichshell were found out. The depletion in the Os 5d5/2 and Pt 5d5/2,3/2 states was revealed for Pt-Os nanoalloys.
This unusual result disagrees with the known d-band theory and indicates that there is a gain of non-d conduction electron counts at one or both sites. Mixed conductivity may exist in such Pt-Os nanoalloy that may be responsible for a manifestation of new physical properties of this binary system .
KW - Bimetallic alloy
KW - Nanoalloy
KW - Synchrotron radiation
KW - XAFS
KW - Electronic structure
KW - Alloy morphology
PY - 2021
DO - https://doi.org/10.1007/s11051-021-05378-z
SN - 1388-0764
VL - 24
IS - 1
SP - 1
EP - 23
PB - Springer
AN - OPUS4-55347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Rethmier, Michael
T1 - A study of the magnetohydrodynamic effect on keyhole dynamics and defect mitigation in laser beam welding
N2 - In this paper, the highly transient keyhole dynamics, e.g., laser absorption, keyhole geometry, and fluctuation, etc., under a magnetic field are investigated using an experimental approach and multi-physical modeling. The model provides accurate predictions to the variation of penetration depth and weld pool profiles caused by the MHD effect, which is validated by the measurements of optical micrographs and in-situ metal/glass observation. The micro-X-ray computed tomography shows a remarkable reduction of keyhole-induced porosity with the magnetic field. The correlation between the porosity mitigation and the weld pool dynamics influenced by the magnetic field is built comprehensively. It is found that the magnetic field gives a direct impact on the laser energy absorption at the keyhole front wall by changing the protrusion movement. The porosity mitigation comes from multiple physical aspects, including keyhole stabilization, widening of the bubble floating channel, and the electromagnetic expulsive force. Their contributions vary according to the bubble size. The findings provide a deeper insight into the relationship between electromagnetic parameters, keyhole dynamics, and suppression of keyhole-relevant defects.
KW - Laser beam welding (LBW)
KW - Keyhole dynamics
KW - Porosity
KW - Magnetohydrodynamics (MHD)
KW - X-ray computed tomography
KW - Multi-physical modeling
PY - 2022
DO - https://doi.org/10.1016/j.jmatprotec.2022.117636
SN - 0924-0136
VL - 307
SP - 117636
PB - Elsevier B.V.
AN - OPUS4-55378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spaltmann, Dirk
T1 - Tribological performance of FS-laser-induced periodic surface structures on titanium alloy against different counter-body materials using a ZDDP lubricant additive
N2 - In this study the so-called laser-induced periodic surface structures (LIPSS, ripples) were produced on titanium alloy (Ti6Al4V) surfaces upon scan processing in air by a Ti:sapphire femtosecond (fs) laser. The tribological performance of the resulting surfaces was qualified in linear reciprocating sliding tribological tests (RSTT) against balls made of different materials (100Cr6 steel/Al2O3/Si3N4) using different oil-based lubricants. The admixture of the additive 2-ethylhexylzinc-dithiophosphate (ZDDP) to a base oil containing only anti-oxidants and temperature stabilizers disclosed the synergy of the additive with the laser-oxidized nanostructures. This interplay between the laser-textured sample topography and the local chemistry in the tribological contact area reduces friction and wear.
T2 - 7th World Tribology Congress - WTC 2022
CY - Lyon, France
DA - 11.07.2022
KW - Lubricant additives
KW - Laser-induced periodic surface structures (LIPSS)
KW - Wear
KW - Friction
PY - 2022
AN - OPUS4-55318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Woydt, M.
T1 - Slip-rolling resistant steel alloys up to P0max = 3,920 MPa under lubricated conditions
N2 - Downsizing (power-to-weight ratio) and higher speeds lead to a rise in Hertzian contact pressures in combination with an increase in surface or oil temperatures. Under such conditions, commonly used bearing steels, such as 100Cr6, reach their limits, creating a demand for alternative slip-rolling resistant steel alloys. The present work therefore compares the slip-rolling performance of various steel types with Maraging- and PM-type steel alloys in the Hertzian contact pressure range up to P0max of 4 GPa.
T2 - 7th World Tribology Congress - WTC 2022
CY - Lyon, France
DA - 11.07.2022
KW - Steel
KW - Alloy
KW - Slip-rolling
KW - Friction
KW - Wear rate
KW - Contact pressure
PY - 2022
AN - OPUS4-55320
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
T1 - MGA Round Robin Test on Al-AM Fatigue Testing - Fractographic Results
N2 - Presentation of results of an investigation of fracture mechanisms and crack start sites of an additive manufactured aluminium alloy after fatigue testing. Collaboration within the MGA initiative (Mobility Goes Additive).
T2 - MGA Mid Term Meeting 2022
CY - Berlin, Germany
DA - 05.07.2022
KW - Aluminium Alloy
KW - Fractography
KW - Additive Manufacturing
PY - 2022
AN - OPUS4-55192
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gupta, P.
A1 - Karnaushenko, D. D.
A1 - Becker, C.
A1 - Okur, I. E.
A1 - Melzer, Michael
A1 - Özer, B.
A1 - Schmidt, O. G.
A1 - Karnaushenko, D.
T1 - Large Scale Exchange Coupled Metallic Multilayers by Roll-to-Roll (R2R) Process for Advanced Printed Magnetoelectronics
N2 - Till now application of printed magnetoelectronics is hindered by lack of large area exchange coupled metallic multilayers required to produce printable magneto-sensory inks. Large-scale roll-to-roll (R2R) fabrication process is an attractive approach owing to its capabilities for high volume, high throughput, and large area manufacturing. Precise and high performance R2R sputtering technology is developed to fabricate large area giant magnetoresistive (GMR) thin-films stacks that contain 30 metallic bilayers prepared by continuous R2R sputtering of Co and Cu sequential on a hundred meters long polyethylene terephthalate (PET) web. The R2R sputtered Co/Cu multilayer on a 0.2 × 100 m2 PET web exhibits a GMR ratio of ≈40% achieving the largest area exchange coupled room temperature magneto-sensitive system demonstrated to date. The prepared GMR thin-film is converted to magnetosensitive ink that enables printing of magnetic sensors with high performance in a cost-efficient way, which promotes integration with printed electronics. An average GMR ratio of ≈18% is obtained for 370 printed magnetic sensors. The realized precise R2R sputtering approach can also be extended to a wide range of hybrid thin-film material systems opening up a path for new functional inks applied with printing technologies.
KW - Printed Electronics
KW - Flexible Magnetic Sensors
KW - Roll-to-Roll Processing
KW - Functional Materials
KW - Upscaling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552344
DO - https://doi.org/10.1002/admt.202200190
SN - 2365-709X
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim, Deutschland
AN - OPUS4-55234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Trash to treasure: recovery of transition metal phosphates for (electro-)catalytical applications
N2 - Wastewaters containing high concentrations of NH4+, PO43- and transition metals are environmentally harmful and toxic pollutants. At the same time phosphorous and transition metals constitute valuable resources. Here, we report the synthesis routes for Co- and Ni-struvites (NH4MPO4∙6H2O, M = Ni2+, Co2+) out of aqueous solutions resembling synthetic/industrial waste water compositions, and allowing for P, ammonia and metal co-precipitation. Furthermore, the as-obtained struvites were further up-cycled. When heated, these transition metal phosphates (TMPs) demonstrate significant changes in the degree of crystallinity/coordination environment involving a high amount of amorphous phases and importantly develop mesoporosity (Figure 1). In this regard, amorphous and mesoporous TMPs are known to be highly promising (electro-)catalysts.
Amorphous phases do not represent a simple “disordered” crystal but more a complex system with a broad range of compositions and physicochemical properties, which remain mostly unknown. Consequently, we investigated the recrystallization and amorphization process during thermal treatment and a resolved the complex amorphous/crystalline structures (Figure 2). As a proof-of-principle for their applicational use, the as-obtained TMPs demonstrate significant proton conductivity properties similar to apatite-like structures from room to high temperatures (>800°C).
Hence, we have developed a promising recycling route in which environmental harmful contaminants like PO43-, NH4+ and 3d metals would be extracted out of waste waters in the form of precursor raw materials. These raw materials can be then further up-cycled through a simple thermal treatment for their specific application in electrocatalysis.
T2 - Goldschmidt Conference 2022
CY - Hawai'i, USA
DA - 10.07.2022
KW - Mesoporosity
KW - Amorphous phases
KW - Transition metals
KW - Struvite
KW - Phosphates
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552852
UR - https://conf.goldschmidt.info/goldschmidt/2022/meetingapp.cgi/Paper/9501
AN - OPUS4-55285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - I n situ monitoring of growing oxidation of the chemically complex alloy AlMo 0.5 NbTa 0.5 TiZr in the high temperature regime using synchrotron radiation Preliminary results
N2 - The chemically complex alloys (CCAs) that contain mostly refractory elements (rCCAs), may be highly resistant to heat and load, which makes them attractive candidates for use at extremely high temperatures associated with many technological applications, e.g. aeroengine turbines. However, the field of CCAs, especially their resistance in harsh (oxidative) and hot environment is still young and not much experimental evidence for the understanding mechanisms in this regime is available, which the proposed study addresses. For safe use in structural applications, in addition to their mechanical performance, the environmental resistance of this alloy is also critical. Surface degradation can significantly decrease the mechanical resistance during high temperature exposure, leading to premature failure. The AlMo0.5NbTa0.5TiZr rCCA only contains Al as a protection candidate and it is composed of a coherent B2/bcc nanoscopic cube-on-cube interweave and an hexagonal phase. The evaluation of the oxidation process in the AlMo0.5NbTa0.5TiZr rCCA in the heat-treated state has not been assessed yet. The proposed study focusses on a deeper understanding of the formation mechanism and growth kinetics of oxides at high temperature in the AlMo0.5NbTa0.5TiZr rCCA using synchrotron radiation. Due to the envisaged high temperature structural applications, the alloy is evaluated in an oxidation environment specifically between 800°C and 1000°C.
T2 - Large scale facility-based techniques SPP meeting
CY - Online meeting
DA - 02.11.2021
KW - Refractory chemically complex alloys
KW - Oxidation behavior
KW - Microstructural analysis
KW - Synchrotron radiation
PY - 2021
AN - OPUS4-54383
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Konformitätsbewertungsstelle Explosivstoffe/Pyrotechnik - Geschäftsbericht für 2021
N2 - Der Vortrag gibt einen kurzen Überblick zum Thema Statistik Konformitätsbewertung im Bereich Explosivstoffe und pyrotechnische Gegenstände,aktuelle Herausforderungen und Information zu dem zu erwartenden Normungsauftrag.
T2 - 24. Sitzung des Beirats der BAM-Zertifizierungsstelle (BZS)
CY - Online meeting
DA - 24.02.2022
KW - Pyrotechnik
KW - Explosivstoffe
KW - Normungsauftrag
PY - 2022
AN - OPUS4-54393
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macková, A.
A1 - Malinský, P.
A1 - Jagerová, A.
A1 - Mikšová, A.
A1 - Lalik, O.
A1 - Nekvindová, P.
A1 - Mistrík, J.
A1 - Marvan, P.
A1 - Sofer, Z.
A1 - Holý, V.
A1 - Schütter, Jan David
A1 - Kentsch, U.
A1 - Azarov, A.
A1 - Galeckas, A.
T1 - Energetic Au ion beam implantation of ZnO nanopillars for optical response modulation
N2 - Nanopillars of ZnO were implanted with Au-400 keV ions at various ion fluences from 1 × 1015 cm−2 to 1 × 1016 cm−2 and subsequently annealed at 750 °C for 15 min in order to reduce the implantation damage and to support Au nanoparticle (NP) aggregation. It was found that implantation-induced effects and thermal effects influence the Au NP coalescence as well as the quality of the ZnO nanopillars. Rutherford Back-Scattering spectrometry (RBS) showed the broader Au-depth profiles than it was theoretically predicted, but the Au-concentration maximum agrees well with prediction taking into account the effective ZnO layer density. The implantation at the higher fluences induced the morphology modification of the nanopillar layer evidenced by RBS and scanning electron microscopy (SEM). An indirect evidence of this effect was given by optical ellipsometry due to gradual refractive index changes in the ZnO nanopillars with the increased Au-ion fluence. Optical characterization of the Au-implanted and annealed nanopillars performed by means of photoluminescence (PL) and diffuse-reflectance spectroscopy (DRS) evidenced the surface plasmon resonance (SPR) activity of the embedded Au NPs. The SPR-enhanced scattering and PL emission observed in the spectral range 500–650 nm are ascribed to Au NPs or more complex Au-clusters. In addition, the ellipsometry measurements of extinction coefficient are found to corroborate well results from DRS, both indicating increase of SPR effect with the increase of Au-ion fluence and after the post-annealing.
KW - ZnO nanopillars
KW - Ion beam implantation
PY - 2022
DO - https://doi.org/10.1088/1361-6463/ac5486
VL - 55
IS - 21
SP - 1
EP - 14
PB - IOP Publishing
AN - OPUS4-54394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Fachbereich 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik
N2 - Vorstellung der Kernaufgaben Konformitätsbewertung Explosivstoffe und pyrotechnische Gegenstände und Hauptaktiviäten in diesem Sektor
T2 - 42. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 15.10.2021
KW - Explosivstoffe
KW - Pyrotechnik
KW - Normung
KW - Konformitötsbewertung
KW - Politikberatung
PY - 2021
AN - OPUS4-54396
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Treninkov, I. A.
A1 - Petrushin, N. V.
A1 - Epishin, A. I.
A1 - Svetlov, I. L.
A1 - Nolze, Gert
A1 - Elyutin, E. S.
T1 - Experimental Determination of Temperature Dependence of Structural–Phase Parameters of Nickel-Based Superalloy
N2 - The temperature dependences of the periods of the crystal lattices of the γ and γ' phases, their dimensional mismatch (misfit), and volume fraction of the γ' phase of an experimental single-crystal hightemperature nickel-based alloy have been determined by X-ray diffraction analysis in the temperature range of 18–1150°C. The temperature ranges in which intense changes in the structural and phase characteristics of the alloy under study take place have been determined.
KW - X-ray diffraction analysis
KW - High temperatures
KW - Nickel-based superalloys
KW - Single crystal
KW - Crystal lattice period
PY - 2022
DO - https://doi.org/10.1134/s2075113322010373
SN - 2075-1133
VL - 13
IS - 1
SP - 171
EP - 178
PB - Springer Science + Business Media
CY - Dordrecht
AN - OPUS4-54466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - Ca-MOFs with varying fluorination degree
N2 - In current Li-ion batteries electrode materials consist typically of inorganic materials, such as LiCoO2, LiNixCoyMn1-zO2, LiFePO4, Li4Ti5O12. These materials struggle with toxicity or limited mineral resources, making them expensive. Therefore, eco-friendly, sustainable, and low-cost alternatives are researched for in recent years. A series of organic compounds were investigated as electrode materials for alkali-ion batteries. Among them organic carbonyl-based materials show reversible storage of lithium- or sodium-ions. Metal terephthalates stand out with their easy synthesis, moderate operational voltage and enhanced dissolution stability compared to other organic compounds. One degradation pathway consists of the dissolution of the electrode material by HF, formed in a side reaction by water and the fluorous electrolyte. Fluorinated metal terephthalates could offer higher dissolution stability against HF and less contamination by water due to their increased hydrophobicity.
The goal of this project is the synthesis and the investigation of the formation mechanism of a series of calcium-based MOFs with increasing fluorine content. For this purpose, we aimed for the construction of calcium-based MOFs with terephthalic acid (H2-pBDC), 2-fluoro-terephthalic acid (H2-2F-pBDC), 2,3,4,5-tetrafluoroterephthalic acid (H2-pBDC-F4), isophthalic acid (H2-mBDC) and 5-fluoro-isophthalic acid (H2-5F-mBDC).
T2 - SFB 1349 Wintersymposium 2022
CY - Berlin, Germany
DA - 15.03.2022
KW - Mechanochemistry
KW - Electrode materials
KW - Fluorinated MOFs
KW - In situ PXRD
PY - 2022
AN - OPUS4-54478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-Induced Periodic Surface Structures: when Maxwell meets Marangoni
N2 - Laser-Induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any material upon irradiation of solids with intense laser radiation. Nowadays, processing rates of up to m^2/min are enabling new industrial applications in medicine, optics, tribology, biology, etc. Depending on the specific type of LIPSS, their structural sizes typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, however, a controversial and vivid debate has emerged during the last two decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter reorganization processes, i.e. distinctly after the laser irradiation. This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
T2 - 16th International Conference on Laser Ablation (COLA 2021/22)
CY - Matsue, Japan
DA - 24.04.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser ablation
KW - Theoretical modelling
KW - Electromagnetic scattering
KW - Hydrodynamics
PY - 2022
AN - OPUS4-54716
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hübler, Daniela
A1 - Gradt, Thomas
T1 - Effect of different binders and secondary carbides on NbC cermets
T1 - Einfluss unterschiedlicher Binder und Sekundärkarbide auf NbC-Hartmetalle
N2 - Due to the rapidly increasing price of tungsten carbide and the significant health risks associated with the wear products of WC-Co (Co3O4 and Wo3), an alternative is required. Niobium carbide (NbC) is well suited as a cutting tool due to its high melting point and low solubility in iron. So far, NbC-Ni cermets best met the requirements of high hardness and toughness. Various secondary carbides such as VC, Mo2C, TiC, but also WC were added to further improve the hardness.
N2 - Aufgrund des rasanten Preisanstiegs von Wolframcarbid und signifikanter Gesundheitsrisiken, die mit den Verschleißprodukten von WC-Co-Hartmetallen (Co3O4 and Wo3) einhergehen, wird eine Alternative benötigt. Niobcarbid (NbC) ist als Zerspanwerkzeug aufgrund seiner hohen Schmelztemperatur und seiner geringen Löslichkeit in Eisen gut geeignet. Im Vergleich zu reinem NbC, führte eine vollständige Substitution von WC zu NbC-Co zu einem Anstieg der Zähigkeit und Festigkeit. Als alternative Binder wurden anschließend Nickel- und Eisengebundene Binder untersucht. Obwohl eisengebundene Hartmetalle im Vergleich zu NbC-Ni Hartmetallen eine ökonomische und kostengünstigere Alternative darstellen würden, zeigten sie einen höheren Reibkoeffizienten und eine höhere Verschleißrate. Bisher erfüllen die NbC-Ni-Hartmetalle die Anforderungen hinsichtlich einer hohen Härte und Zähigkeit am besten. Verschiedene Sekundärkarbide, wie VC, Mo2C, TiC, aber auch WC wurden zusätzlich hinzugefügt, um die Härte weiter zu steigern. Elementanalysen der NbC-Ni-MeC Hartmetalle (Me = Metall) zeigten, dass der Binder eine kubisch-flächenzentrierter Mischkristall ist, während die NbC Phase ein Mischkristall des Typs (Nb, Me)C ist.
KW - Niobium carbide (NbC)
KW - Cutting tool
KW - Binders
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547202
DO - https://doi.org/10.1007/s10010-022-00583-1
SN - 0015-7899
VL - 86
IS - 2
SP - 197
EP - 211
PB - Springer
CY - Berlin
AN - OPUS4-54720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - On the challenges in achieving comparable and reproducible tribological model tests
N2 - An infrastructure of more than 100 tribometers (for The European Tribology Centre i-TRIBOMAT) requires procedures which ensure that the respective results are characteristic as well as descriptive, trustworthy, comparable, and reproducible.
T2 - Tribology International Conference 2022 (SETCOR)
CY - Barcelona, Spain
DA - 28.04.2022
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Harmonisation
KW - Round robin tests
KW - Interlaboratory tests
PY - 2022
AN - OPUS4-54754
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
T1 - Charakterisierung von Salzbeton und alkali-aktivierten Material basierend auf der Schallemissionsanalyse
N2 - Nach einer kurzen Einführung in die Schallemissionsprüfung und -Analyse wird ein Versuchsstand vorgestellt, der im Rahmen des Themenfeldprojektes Seal Waste Safe installiert wurde. Schwerpunkt des Vortrages sind die Schallemissionsmessungen an einem 150 l Demonstrator aus Salzbeton und einem weiteren aus alkali-aktiviertem Material. Neben der konventionellen Schallemissionsanaylse mit Aktivitäts- und Intensitätsparametern der Zeitsignale, werden auch frequenzbasierte Parameter zur Analyse andiskutiert.
N2 - After a brief introduction to acoustic emission testing and analysis, an experimental test setup is presented, which was part of the Seal Waste Safe project (internal BAM project 2019-2022). Herein, the acoustic emission measurements of a 150 l demonstrator made of salt concrete and another one made of alkali-activated material are focused. In addition to the conventional acoustic emission analysis regarding the activity and intensity parameters of the detected time signals, also frequency-based parameters were discussed for analysis.
T2 - Dauerhafte Verschlussbauwerke für Endlager
CY - Online meeting
DA - 14.2.2022
KW - Acoustic Emission
KW - Schallemission
KW - Salzbeton
KW - Alkali aktiviertes Material
KW - Geopolymer
PY - 2022
AN - OPUS4-54937
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Bestimmung der Partikelgrößenverteilung mittels Zentrifugen-Sedimentationsverfahren nach ISO 13318-2 (Küvette)
N2 - Im Vortrag werden das Messprinzip des Zentrifugen-Sedimentationsverfahrens erläutert und die Anforderungen der zugrundeliegenden Normen diskutiert. Es schließen sich umfangreiche Ausführungen zur praktischen Durchführung der Messung, insbesondere auch zu den vorbereitenden Arbeiten, sowie zur Auswertung der Rohdaten an. Gezeigt werden die Validierung sowie ein Beispiel zur regelmäßigen Verifizierung des Verfahrens. Nach Beispielen und Vergleichen zu Ergebnissen mit anderen Messverfahren, wird das Verfahren in einer Zusammenfassung bewertet.
T2 - Seminar Rheologie und Stabilität von dispersen Systemen
CY - Potsdam, Germany
DA - 09.05.2022
KW - Nano powder
KW - Cetrifugal Liquid Sedimentation CLS
KW - Particle size determination
PY - 2022
AN - OPUS4-54863
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ehlers, Henrik
T1 - Hochauflösende Online Wirbelstromprüfung von PBF LB/M Bauteilen mit GMR Arrays
N2 - In den letzten Jahren haben additive Fertigungstechnologien an Bedeutung gewonnen. Für komplexe Funktionsbauteile oder die Produktion von Werkstücken in kleinen Stückzahlen kann das Laser-Pulverbettschmelzen eingesetzt werden. Hohe Sicherheitsanforderungen, z. B. in der Luft- und Raumfahrt, erfordern eine umfassende Qualitätskontrolle. Daher werden nach der Fertigung zerstörungsfreie Offline-Prüfverfahren wie die Computertomographie eingesetzt. In jüngster Zeit wurden zur Verbesserung der Rentabilität und Praktikabilität zerstörungsfreie Online-Prüfverfahren wie die optische Tomographie entwickelt. In diesem Beitrag wird die Anwendbarkeit der Wirbelstromprüfung mit GMR Sensoren für die online Prüfung von PBF-LB/M Teilen demonstriert. Die Ergebnisse einer online Wirbelstromprüfung mit GMR Sensoren und einer Ein-Draht-Anregung werden gezeigt. Während des Produktionsprozesses wird für jede Lage eine Wirbelstromprüfung durchgeführt. Trotz hochauflösender Arrays mit 128 Elementen wird durch eine angepasste Hardware die Prüfdauer geringgehalten. So kann die Messung während des Beschichtungsvorgangs durchgeführt werden, ohne den Fertigungsprozess signifikant zu verlangsamen. Eine online Wirbelstromprüfung eines stufenförmigen Testkörpers aus Haynes282 über 184 Lagen zeigt, dass die Kanten nicht nur in der aktuellen Lage detektiert werden können, sondern auch in einer Tiefe von 400 µm, wenn eine Anregungsfrequenz von 1,2 MHz gewählt wird.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Wirbelstrom
KW - Additive Fertigung
KW - GMR
KW - PBF
PY - 2022
AN - OPUS4-54899
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guillaume, F.
A1 - Knorr, Annett
A1 - Rotureau, P.
T1 - First QSPR models to predict the thermal stability of potential self-reactive substances
N2 - Self-reactive substances are unstable chemical substances which can easily decompose and may lead to explosion in transport, storage, or process situations. For this reason, their thermal stability properties are required to assess possible process safety issues and for classification purpose. In this study, the first quantitative structure–property relationships (QSPR) dedicated to this class of compounds were developed to predict the heat of decomposition of possible self-reactive substances from their molecular structures. The database used to develop and validate the models was issued from a dedicated experimental campaign on 50 samples using differential scanning calorimetry in homogeneous experimental conditions. QSPR models were derived using the GA-MLR methods (using a genetic algorithm and multi-linear regressions) using molecular descriptors calculated by Dragon software based on two types of inputs: 3D molecular structures determined using the density functional theory (DFT), allowing access to three-dimensional descriptors, and from SMILES codes, favoring the access to simpler models, requiring no preliminary quantum chemical calculations. All models respected the OECD validation guidelines for regulatory ac
ceptability of QSPR models. They were tested by internal and external validation tests and their applicability domains were defined and analyzed.
KW - Self-reactive substances
KW - Quantitative Structure-Property Relationships
KW - Thermal stability
KW - Genetic algorithm
PY - 2022
DO - https://doi.org/10.1016/j.psep.2022.05.017
SN - 0957-5820
VL - 163
SP - 191
EP - 199
PB - Elsevier Ltd.
AN - OPUS4-55631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tang, Chi-Long
T1 - Proposal of a standard test method for the quantification of particulate matter during 3D printing and the systematic ranking of filament materials
N2 - The diversity of fused filament fabrication (FFF) filaments continues to grow rapidly as the popularity of FFF-3D desktop printers for the use as home fabrication devices has been greatly increased in the past decade. Potential harmful emissions and associated health risks when operating indoors have induced many emission studies. However, the lack of standardization of measurements impeded an objectifiable comparison of research findings. Therefore, we designed a chamber-based standard method, i.e., the strand printing method (SPM), which provides a standardized printing procedure and quantifies systematically the particle emission released from individual FFF-3D filaments under controlled conditions. Forty-four marketable filament products were tested. The total number of emitted particles (TP) varied by approximately four orders of magnitude (1E9 ≤ TP ≤ 1E13), indicating that origin of polymers, manufacturer-specific additives, and undeclared impurities have a strong influence. Our results suggest that TP characterizes an individual filament product and particle emissions cannot be categorized by the polymer type (e.g., PLA or ABS) alone. The user's choice of a filament product is therefore decisive for the exposure to released particles during operation. Thus, choosing a filament product awarded for low emissions seems to be an easily achievable preemptive measure to prevent health hazards.
T2 - 11th International Aerosol Conference
CY - Athens, Greece
DA - 04.09.2022
KW - Ultrafine particles
KW - FFF-3D-Printer
KW - Indoor emission
KW - Emission test chamber
KW - Test method
KW - Exposure risk
PY - 2022
AN - OPUS4-55666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Valet, Svenja
T1 - Determination of the corrosion product layer resistance on zinc samples by using gel electrolytes
N2 - Crash barriers, railings, lamp posts, waste glass containers - these are just a few of the many examples of galvanized surfaces. They withstand wind and weather for decades, which is possible thanks to a protective layer made of corrosion products. When designing the atmospheric durability of galvanized components, a linear corrosion loss is assumed. In the past 30 years, however, the surrounding atmosphere has changed a lot. Due to the restriction of sulfur exhaust air, acid rain completely disappeared in Europe and Germany, which has a direct influence on the type and protective effect of the corrosion products. Under the influence of current atmospheric conditions, zinc layers are significantly more resistant and no longer show any linear corrosion loss. The established test methods cannot correctly map this change in neither short-term nor long-term tests and thus provide incorrect results. In order to solve this problem, a new measurement method was developed at BAM that can assess the protective effect of the formed surface layers in a minimally invasive manner without damaging the sample and in short test times. For this new method, gel electrolytes are used and the so-called corrosion product layer resistance RL, which is made up of various surface resistances, is measured electrochemically. As a single measurement, the surface layer resistance can provide information about the existing corrosion protection, while time-dependent measurements assess the stability of the layer. Thus, it is possible again to evaluate the corrosion protection layer. Furthermore, this method can also be used for field measurements on real components.
T2 - EUROCORR 2022
CY - Berlin, Germany
DA - 28.08.2022
KW - Corrosion
KW - Corrosion Testing
KW - Gel electrolytes
KW - Zinc and galvanized samples
KW - Corrosion product layer
PY - 2022
AN - OPUS4-55688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simon, Franz-Georg
T1 - Product testing and performance
N2 - Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80° C
and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years.
T2 - EuroGeo-7, Session Geosynthetics, Sustainability and Current Industry Challenges
CY - Warschau, Poland
DA - 04.09.2022
KW - Geosynthetics
KW - Ageing
KW - Autoclave tests
PY - 2022
AN - OPUS4-55671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deumer, J.
A1 - Pauw, Brian Richard
A1 - Marguet, S.
A1 - Skroblin, D.
A1 - Taché, O.
A1 - Krumrey, M.
A1 - Gollwitzer, C.
T1 - Small-angle X-ray scattering: characterization of cubic Au nanoparticles using Debye’s scattering formula
N2 - A versatile software package in the form of a Python extension, named CDEF (computing Debye’s scattering formula for extraordinary form factors), is proposed to calculate approximate scattering profiles of arbitrarily shaped nanoparticles for small-angle X-ray scattering (SAXS). CDEF generates a quasi-randomly distributed point cloud in the desired particle shape and then applies the open-source software DEBYER for efficient evaluation of Debye’s scattering formula to calculate the SAXS pattern (https://github.com/j-from-b/CDEF). If self-correlation of the scattering signal is not omitted, the quasi-random distribution provides faster convergence compared with a true-random distribution of the scatterers, especially at higher momentum transfer. The usage of the software is demonstrated for the evaluation of scattering data of Au nanocubes with rounded edges, which were measured at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II in Berlin. The implementation is fast enough to run on a single desktop computer and perform model fits within minutes. The accuracy of the method was analyzed by comparison with analytically known form factors and verified with another implementation, the SPONGE, based on a similar principle with fewer approximations. Additionally, the SPONGE coupled to McSAS3 allows one to retrieve information on the uncertainty of the size distribution using a Monte Carlo uncertainty estimation algorithm.
KW - X-ray scattering
KW - SAXS
KW - Non-spherical nanoparticles
KW - Nanoparticles
KW - Nanomaterials
KW - Debye scattering equation
KW - Simulation
KW - Data fitting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557652
DO - https://doi.org/10.1107/S160057672200499X
VL - 55
IS - Pt 4
SP - 993
EP - 1001
PB - International Union of Crystallography
CY - Chester, England
AN - OPUS4-55765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönauer-Kamin, Daniela
T1 - Powder-Aerosol deposited (PAD) calcium manganate as n-type thermoelectric material
N2 - Currently, calcium manganate CaMnO3 and calcium cobaltite Ca3Co4O9 are being investigated as n-type resp. p-type semiconducting materials as oxidation- and temperature-resistant thermoelectric materials for oxide multilayer thermoelectric generators (TEGs). In order to manufacture multilayer TEGs, pressure-assisted sintering processes at high temperatures are necessary to achieve optimal thermoelectric material properties. To realize TEGs in planar film technology, another method to obtain dense ceramic layers directly from the synthesized starting powders without a subsequent high temperature step is emerging recently: the powder aerosol deposition (PAD) method. In the present work, it is investigated whether PAD is suitable to produce dense ceramic films from Sm-doped CaMnO3 and Ca3Co4O9 powders. The resulting thermoelectric properties are characterized as a function of temperature.
CaMnO3 powder could successfully be processed by PAD with resulting layer thicknesses of 5- 6 µm without any high-temperature sintering steps of the films. The electrical conductivity and the Seebeck coefficient of the films were determined in-plane from room temperature to 600 °C in air. The results show a Seebeck coefficient of around -200 µV/K, which is comparable to results of pressed and sintered bars. At 400 °C, the electrical conductivity corresponds to the conductivity of the bar. At higher temperatures the conductivity is better than with the reference. Below 400°C, the electrical conductivity is somewhat lower than that of the reference sample, a mild thermal treatment of the PAD layer improves it. It is expected that the thermal conductivity of the PAD film will be lower compared to the bars due to the nano-crystalline film morphology. This should result in a significantly increased ZT value for the PAD layers and a higher efficiency of the TEG.
The work shows that both CaMnO3 and Ca3Co4O9 can be successfully processed by PAD, and the PAD films show comparable thermoelectric properties.
T2 - 18th European Conference on Thermoelectrics
CY - Barcelona, Spanien
DA - 14.09.2022
KW - Film depositition
KW - Calcium cobaltite
PY - 2022
AN - OPUS4-55771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Vorstellung des Konzeptes und der Ziele des Arbeitskreises „Atmosphärische Korrosion“
N2 - Der Vortrag wurde im Rahmen der konstituierenden Sitzung des Arbeitskreises "Atmosphärische Korrosion" der GfKORR - Gesellschaft für Korrosionsschutz e.V. gehalten. Er stellt die zur Diskussion stehenden Fragestellungen und Herausforderungen im Bereich der atmosphärischen Korrosion zusammen, denen sich der neue Arbeitskreis widmen wird.
T2 - Konstituierende Sitzung des GfKORR-Arbeitskreises „Atmosphärische Korrosion“
CY - Frankfurt a. M., Germany
DA - 19.09.2022
KW - Atmosphärische Korrosion
KW - Korrosion
KW - Korrosionsschutz
PY - 2022
AN - OPUS4-55772
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schwarz, Silke
T1 - Elektrostatische Empfindlichkeit von Explosivstoffen: Grundlagen, Messprinzip und erste Ergebnisse mit dem X-Spark-10
N2 - Der Vortrag stellt die neuesten Entwicklungen an der BAM zur Bestimmung der elektrostatischen Empfindlichkeit von Explosivstoffen dar. Ausgehend von der Motivation unsererseits diese Thematik wieder intensiver zu bearbeiten werden ein neues Messgerät und erste Ergebnisse vorgestellt. Lücken im sicherheitstechnischen Regelwerk zur Einstufung von Explosivstoffen hinsichtlich ihrer elektrostatischen Empfindlichkeit und daraus abgeleiteter Schutzmaßnahmen in der Industrie werden dargestellt.
T2 - BG RCI Erfahrungsaustausch "Explosivstoff-Industrie"
CY - Bremerhaven, Germany
DA - 22.09.2022
KW - Explosivstoffe
KW - elektrostatische Empfindlichkeit
PY - 2022
AN - OPUS4-55750
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Junge, P.
A1 - Stargardt, Patrick
A1 - Kober, D.
A1 - Greinacher, M.
A1 - Rupprecht, C.
T1 - Thermally Sprayed Al2O3 Ceramic Coatings for Electrical Insulation Applications
N2 - Thermal spraying enables a fast and propelling way to additively deposit various ceramics as electric insulators, which are used in conditions where polymers are not suitable. Alumina (Al2O3) is among the most employed materials in the coating industry since it exhibits good dielectric properties, high hardness, high melting point while still being cost-effective. Various parameters (e.g. feedstock type, plasma gas mixture, plasma power) significantly influence the resulting coating in terms of microstructure, porosity, crystallinity, and degree of un-or molten particles. As a consequence, these parameters need to be investigated to estimate the impact on the electrical insulating properties of thermally sprayed alumina. This study focuses on the development of a novel electric insulation coating from Al2O3 feedstock powders deposited via atmospheric plasma spray (APS). The microstructure, porosity, and corresponding crystallographic phases have been analyzed with optical microscopy, XRD, and SEM images. To achieve an understanding of the parameters influencing the electrical insulation performance of the manufactured coatings, an in-depth analysis of the fundamental dielectric parameters e.g., DC resistance, breakdown strength, dielectric loss tangent, permittivity is presented.
T2 - International Thermal Spray Conference and Exposition 2022
CY - Vienna, Austria
DA - 04.05.2022
KW - Thermal Spray
KW - Alumina
KW - Dielectric properties
PY - 2022
SP - 1
EP - 8
AN - OPUS4-55821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotula, Stefan
T1 - Zinkbeizen nach alter ISO 8407
N2 - Der Vortrag beschäftigt sich mit der Problemstellung der Entfernung von Korrosionsprodukten auf Zinkoberflächen zur Bewertung des Masseverlustes. Er diskutiert die Diskrepanzen zwischen der alten Version der ISO 8407 und der aktuellen Version.
T2 - Sitzung des DIN-Gemeinschaftsarbeitskreises NA 062 01 77 01 GAK
CY - Online Meeting
DA - 22.09.2022
KW - Atmosphärische Korrosion
KW - Deckschichtbildung
KW - ISO 8407
KW - Korrosion
PY - 2022
AN - OPUS4-55807
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced Periodic Surface Structures (LIPSS): Mechanisms, Applications, and unsolved Problems
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m^2/min level, industrial applications of LIPSS are sometimes limited by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches. Moreover, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry
T2 - 10th International LIPSS Workshop 2022
CY - Orléans, France
DA - 21.09.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Femtosecond laser processing
KW - Time-resolved coherent scattering
PY - 2022
AN - OPUS4-55814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Singh, S.
A1 - Palani, I. A.
A1 - Paul, C. P.
A1 - Funk, Alexander
A1 - Gokuldoss, P. K.
T1 - Wire Arc Additive Manufacturing of NiTi 4D Structures: Influence of Interlayer Delay
N2 - Shape memory alloy structures for actuator and vibration damper applications may be manufactured using wire arc additive manufacturing (W AAM), which is one of the additive manufacturing technologies. Multilayer deposition causes heat accumulation during W AAM, which rises the preheat temperature of the previously created layer. This leads to process instabilities, which result in deviations from the desired dimensions and mechanical properties changes. During W AAM deposition of the wall structure, a systematic research is carried out by adjusting the interlayer delay from 10 to 30 s. When the delay period is increased from 10 to 30 s, the breadth decreases by 45% and the height increases by 33%. Grain refinement occurs when the interlayer delay duration is increased, resulting in better hardness, phase transformation temperature, compressive strength, and shape recovery behavior. This study shows how the interlayer delay affects the behavior of W AAM-built nickel-titanium alloy (NiTi) structures in a variety of applications.
KW - Wire are additive manufacturing
KW - Shape memory alloy
KW - Nitinol
KW - Interlayer delay
PY - 2022
DO - https://doi.org/10.1089/3dp.2021.0296
SN - 2329-7662
SP - 1
EP - 11
PB - Liebert
CY - New Rochelle, NY
AN - OPUS4-55795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mehri, S.
A1 - Kolmangadi, Mohamed Aejaz
A1 - Dyre, J.C.
A1 - Ingebrigtsen, T.S.
T1 - Lines of invariant physics in the isotropic phase of the discotic Gay-Berne model
N2 - The Gay-Berne model is studied numerically with a choice of parameters allowing for the formation of a discotic liquid crystal at low temperatures. We show that the model has strong virial potential-energy correlations in the isotropic phase at high temperatures, i.e., it obeys the criterion for the existence of isomorphs, which are curves of approximately invariant structure and dynamics. These properties are demonstrated to be approximately invariant in reduced units along the isomorph studied. The isomorph is described well by the constant density-scaling exponent 11.5, a number that is significantly larger than the density-scaling exponents of various Lennard-Jones models that are always below 6.
KW - Liquid Crystal
KW - Molecular Dynamics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547611
DO - https://doi.org/10.1016/j.nocx.2022.100085
VL - 14
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-54761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishmastnehi, Moslem
A1 - Stawski, Tomasz
T1 - Crystals of Gypsum in Hands of Masters
N2 - The microstructure of most Seljuk and Ilkhanid stucco decorations consists of micrometer-sized crystals of gypsum. The stucco-masters of these periods (neither nowadays stucco-masters) were not able to directly control the properties of these tiny crystals with their hands or centimeter-sized tools. There are, however, traces of chaîne opératoire accumulated in the materialistic body of these pieces, some of which could be explored through an interdisciplinary approach. Such an investigation requires very careful in situ observation of the macrostructure, and scientific analyses of the material to discover part of the production process for each body of stucco. Furthermore, there are deterioration factors, some of which are not yet fully understood, and should be identified using modern analytical instruments. These damaging factors could easily affect the micro and macro structure of a stucco decoration, influencing our interpretation. The concept of chaîne opératoire reframes our questions about the production process and probable dating technique of Seljuk and Ilkhanid stuccoes, while analyses of labmade replicas and historic materials enhance our understanding and interpretation of these materials. Here we present the results of such a study for a large body of Seljuk and Ilkhanid stucco decorations at various sites in Iran, and present the potential of this approach as a new perspective in this field of research.
T2 - Stucco in the Architecture of Iran and Neighbouring Lands
CY - Bamberg, Germany
DA - 04.05.2022
KW - Gypsum
KW - Stuccos
KW - Crystallization
PY - 2022
AN - OPUS4-54782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Eine digital gestützte Qualitätssicherung für die additive Fertigung
N2 - Die additive Fertigung (ugs. „3D-Druck“) ist bei der Herstellung von hochkomplexen metallischen Bauteilen, bionisch inspiriertem Leichtbau oder Prototypen nicht mehr wegzudenken.
Für die konventionelle Fertigung hat sich das bestehende System der Qualitätsinfrastruktur (QI) bewährt. Die additive Fertigung vergrößert den gestalterischen Spielraum von möglichen Bauteilgeometrien und Prozessfehlern jedoch erheblich. Hier gerät die QI an ihre Grenzen, sodass die Fertigung und Zulassung sicherheitsrelevanter Bauteile sehr zeit- und kostenintensive Versuche erfordern. Eine moderne digitale QI erlaubt eine effizientere Qualitätssicherung für additiv gefertigte Bauteile. Dies erfordert eine durchgängig digitale Abbildung des physischen Materialflusses.
T2 - Werner-von-Siemens Centre for Industry and Science - AM Querschnittstreffen
CY - Online meeting
DA - 21.06.2022
KW - Additive Fertigung
KW - Qualitätssicherung
KW - Digitalisierung
PY - 2022
AN - OPUS4-55127
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Svetlov, I. L.
A1 - Epishin, A. I.
A1 - Petrushin, N. V.
A1 - Gerstein, G.
A1 - Nolze, Gert
A1 - Maier, H. J.
T1 - Creep of Directionally Solidified Eutectics Ni/Ni3 Al–NbC under Thermal Cycling
N2 - A nickel-based eutectic alloy with a γ/γ'-NbC structure was directionally solidified with a planar front. The specimens were tested for creep under sawtooth thermal cycling in the temperature range from 600 to 1100°C. It has been established that the lifetime under the conditions of thermal cycling is about five times shorter than it is predicted by the linear damage accumulation rule on the basis of results of isothermal creep tests. Faster creep under thermal cycling is caused by the rapid coarsening of the γ/γ' microstructure due to the periodic partial dissolution and reprecipitation of the γ' phase in heating and cooling half-cycles.
KW - High temperature nickel-based eutectic alloys
KW - γ/γ' matrix
KW - Carbide phase NbC
KW - In-situ composites
KW - Creep under thermal cycling
PY - 2022
DO - https://doi.org/10.1134/S2075113322040347
SN - 2075-1133
VL - 13
IS - 4
SP - 1099
EP - 1108
PB - Springer Science + Business Media
CY - Dordrecht
AN - OPUS4-55163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Oxidkeramische Werkstoffe und Folien für thermoelektrische Multilayergeneratoren
N2 - Thermoelektrische Effekte beschreiben die direkte Verknüpfung von thermischer Energie und elektrischer Energie in Festkörpern. Durch Thermodiffusionsströme entsteht direkt, ohne beweg¬liche Teile, ein elektrisches Feld als Folge einer Temperaturdifferenz. Diese Material-eigenschaft wird durch den Seebeckkoeffizienten beschrieben. Je nach Art der Ladungs¬träger sind die indu¬zierte Spannung und der Seebeckkoeffizient positiv (p-Typ) oder negativ (n-Typ). Thermo¬elek¬trische Effekte lassen sich beispielsweise in Thermo¬elementen zur Temperatur-messung, in Pel¬tierelementen zum Kühlen oder Heizen und in thermo¬elektrischen Generatoren zur Umwandlung von thermischer Energie in elektrische Energie nutzen.
In thermoelektrischen Generatoren werden Schenkel aus p-Typ- und n-Typ-Materialien elek-trisch in Reihe und thermisch parallel verschaltet. Konventionell werden einzelne Schenkel aus Bismut¬tellurid auf ein metallisiertes Substrat gelötet. Man spricht vom π-Typ-Design. Aufgrund auf¬wendiger Fertigung und nicht optimaler Flächennutzung stellt dieses Design nicht die best-mög¬liche Lösung dar. Neben Telluriden gibt es noch andere vielversprechende thermoelektrische Material¬systeme wie die oxidischen Thermoelektrika. Im Temperatur¬bereich oberhalb von 700 °C können oxidische thermoelektrische Materialien mit nichtoxidischen konkurrieren. Zudem sind sie oxidationsbeständig und können aus weniger toxischen und besser verfügbaren Rohstoffen her¬ge¬stellt werden. Da es sich um keramische Materialien handelt, können unter Nutzung der Multi¬layer¬technologie (auch Vielschicht- oder Mehrlagentechnik) Generatoren im Multilayer¬design hergestellt werden. Keramische Multi¬layer¬generatoren sind aufgrund der höheren Leis¬tungs¬dichte, der Möglichkeit der gezielten Texturierung und des hohen möglichen Auto¬mati¬sierungs¬grades des Herstellungs¬prozesses eine viel¬versprechende Alternative zu konven¬tionellen π-Typ-Generatoren. Alle Lagen werden in einem Schritt co-gesintert. Die beiden zum jetzigen Zeit¬punkt wohl viel¬versprechendsten oxi¬dischen Thermoelektrika sind Calcium-cobaltit Ca3Co4O9 als p-Typ und Calciummanganat CaMnO3 als n-Typ. Die Sinter¬tem¬peratur von Ca3Co4O9 ist durch eine Phasenumwandlung bei 926 °C beschränkt. Texturiertes, dichtes Ca3Co4O9 mit einer hohen Festigkeit kann nur über Hei߬pressen hergestellt werden. Das Co-Sintern von Ca3Co4O9 und CaMnO3 war wegen der Tem¬pera¬tur¬differenz von 350 K zwischen den jeweiligen Sinterintervallen bisher nicht möglich. Ziel dieser Arbeit war deshalb die Ent¬wick¬lung von kompatiblen oxidkeramischen Werkstoffen und Folien für thermoelektrische Multilayer-generatoren auf der Basis von Ca3Co4O9 und CaMnO3.
Daraus resultieren vier wesentliche Arbeitspakete. Zunächst die Materialentwicklungen von Ca3Co4O9 (p-Typ) und CaMnO3 (n-Typ) für ein Co-Sintern bei 900 °C mit akzeptablen thermoelek¬trischen Eigenschaften, dann die Entwicklung der weiteren im Generator benötigten Kompo¬nenten wie der Isolationsschicht und abschließend die Fertigung und Bewertung von Demonstra¬toren im Multi¬layer¬design.
Foliengießen und druckunterstütztes Sintern ermöglichen die Herstellung von dichtem, tex-turier¬tem Ca3Co4O9 mit hoher Festigkeit und hohem Leistungsfaktor. Letzterer ist das Produkt der elek¬trischen Leitfähigkeit und dem Quadrat des Seebeckkoeffizienten. Für die elektrische Leit¬fähigkeit zeigte sich in dieser Arbeit ein kombinierter Einfluss von Sinterdichte und Textur. Die thermo¬elektrischen Eigen¬schaften lassen sich somit über die Einstellung der Mikrostruktur gezielt steuern.
Durch die Optimierung der Pulversynthese, die Einführung des Sinteradditives CuO und die Kombi¬nation mit dem druckunterstützten Sintern (7,5 MPa) konnte die Sintertemperatur des CaMnO3 bei gleichbleibendem Leistungsfaktor von 1250 °C auf 950 °C gesenkt werden. Druck-unter¬stütztes Sintern von CaMnO3 ist bei 900 °C möglich, führt aber zu einem Werkstoff mit geringerem Leistungsfaktor, geringerer Dichte und ungenügender Festigkeit.
Zur elektrischen Isolation der beiden thermoelektrischen Materialien wurde ein Glas-Keramik-Kompo¬sit mit hohem Volumenwiderstand und angepasstem Wärmeausdehnungs¬koef¬fizienten ent¬wickelt.
Aus den zu Folien vergossenen thermoelektrischen Materialien, der siebgedruckten Iso¬lations-schicht und der siebgedruckten Metallisierung wurden mittels Multilayertech¬nologie De¬mons-tratoren hergestellt. Neben dem pn-Generator aus Ca3Co4O9 und CaMnO3 wurden auch Unileg-generatoren aus Ca3Co4O9 gefertigt. Bei Unileggeneratoren wird die Komplexität des Aufbaus durch die Verwendung von nur einem thermoelektrischen Material verringert. Die Simulation der Demonstratoren zeigte, dass der pn-Generator aus Ca3Co4O9 und CaMnO3 keine höheren Leis-tungsdichten erbringt als der aus nur Ca3Co4O9 bestehende Unileg¬generator. Auf¬grund des ge-ringen Leistungsfaktors und der geringen Festigkeit des bei 900 °C gesinterten CaMnO3 er¬scheint die Fertigung von pn-Multilayer¬generatoren aus Ca3Co4O9 und CaMnO3 derzeit nicht sinn¬voll. Die Unileg¬generatoren aus Ca3Co4O9 erreichen mit sehr hoher Reproduzier¬barkeit 2 mW/cm² bei einer Temperaturdifferenz von 230 K, dies entspricht 80 % der simulierten elektrischen Leistung. Es handelt sich hierbei um den ersten Machbarkeits¬nachweis zur Herstellung von Multilayer-generatoren auf Basis von texturiertem Ca3Co4O9 mit hohem thermoelektrischem Leistungsfaktor, hoher Dichte und hoher Festigkeit.
Solch thermoelektrische Multilayergeneratoren könnten zukünftig Systeme mit geringen elek-trischen Leistungsanforderungen wie Sensoren autark und nachhaltig mit elektrischer Energie ver¬sorgen.
T2 - Promotionskolloquium
CY - Bayreuth, Germany
DA - 25.04.2022
KW - Calciumcobaltit
KW - Calciummanganat
KW - Foliengießen
KW - Sintertemperatur
PY - 2022
AN - OPUS4-54726
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Roed, L.
A1 - Mehri, S.
A1 - Ingebrigtsen, T.
A1 - Hecksher, T.
A1 - Dyre, J.
A1 - Niss, K.
T1 - Predicting nonlinear physical aging of glasses from equilibrium relaxation via the material time
N2 - The noncrystalline glassy state of matter plays a role in virtually all fields of materials science and offers complementary properties to those of the crystalline counterpart. The caveat of the glassy state is that it is out of equilibrium and therefore exhibits physical aging, i.e., material properties change over time. For half a century, the physical aging of glasses has been known to be described well by the material-time concept, although the existence of a material time has never been directly validated. We do this here by successfully predicting the aging of the molecular glass 4-vinyl-1,3-dioxolan-2-one from its linear relaxation behavior. This establishes the defining property of the material time. Via the fluctuation-dissipation theorem, our results imply that physical aging can be predicted from thermal-equilibrium fluctuation data, which is confirmed by computer simulations of a binary liquid mixture.
KW - Physical aging
KW - Equilibrium relaxation
KW - Glass
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546015
DO - https://doi.org/10.1126/sciadv.abl9809
SN - 2375-2548
VL - 8
IS - 11
SP - 1
EP - 8
PB - American Association for the Advancement of Science
CY - Washington, DC
AN - OPUS4-54601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Hygienic assessment of SLM-printed stainless steel
N2 - Elektrochemische Messungen zur hygienischen Bewertung additiv gefertigter Bauteile werden diskutiert. Die Bewertung und Details des Werkstoffs werden beschrieben, Anwendungsbeispiele gezeigt.
T2 - Kormat 2022
CY - Online meeting
DA - 26.04.2022
KW - Korrosion
KW - Trinkwasser
KW - Hygienische Bewertung
KW - Additive Fertigung
PY - 2022
AN - OPUS4-54709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Normung Explosivstoffe & Pyrotechnik - Quo vadis?
N2 - Vorstellung der aktuellen Normungstätigkeiten mit Bezug zu Explosivstoffen und pyrotechnischen Gegenstände.
T2 - 43. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 22.04.2022
KW - Normung
KW - Zünder
KW - Explosivstoffe
KW - Pyrotechnik
KW - Feuerwerk
PY - 2022
AN - OPUS4-54690
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Stawski, Tomasz
ED - Van Driessche, A. E. S.
T1 - Special issue "Formation of sulfate minerals in natural and industrial environments"
N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods.
KW - Calcium sulfate
KW - Sulfates
PY - 2020
UR - https://www.mdpi.com/journal/minerals/special_issues/FSMNIE
SN - 2075-163X
VL - 10(9)-12(3)
SP - 10-812-1
EP - 12-299-3
PB - MDPI
CY - Basel
AN - OPUS4-54700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Misuse of pyrotechnics - a hazard assessment
N2 - The contribution focuses on intentional misuse of pyrotechnic articles, which are for the EU-market CE-marked and tested according to an intended use as declared by the manufacturer. Specific properties of the articles and associated hazards in view of the intended use and - in comparison - the illegal use are presented. Moreover, the basic concepts of the conformity assessment procedures and selected standard requirements for the articles concerned are described.
T2 - Security of Explosives pan-European Specialists Network — EXERTER, Virtual Conference - Year 4, topic: “Criminal use of explosives”
CY - Online meeting
DA - 06.04.2022
KW - Misuse
KW - Pyrotechnics
KW - Explosives
KW - Intended use
PY - 2022
AN - OPUS4-54614
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Van Driessche, A. E. S.
T1 - Editorial for special issue "Formation of sulfate minerals in natural and industrial environments"
N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods.
KW - Calcium sulfate
KW - Sulfates
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546794
DO - https://doi.org/10.3390/min12030299
SN - 2075-163X
VL - 12(3)
IS - Special issue "Formation of sulfate minerals in natural and industrial environments"
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-54679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Fachbereich 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik
N2 - Vorstellung der aktuellen Aufgaben und Tätigkeiten des FB 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik
T2 - 43. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 22.04.2022
KW - Benannte Stelle
KW - Konformitätsbewertung
KW - Normung
KW - FE
KW - Beratung Behörden/Ministerien
PY - 2022
AN - OPUS4-54688
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Forschungsschwerpunkte im Fachbereich 2.5 Konformitätsbewertung Explosivstoffe/Pyrotechnik
N2 - Vorstellung der aktuellen Forschungsthemen mit Bezug zu Explosivstoffen und pyrotechnischen Gegenstände
T2 - 43. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 22.04.2022
KW - Alterung von Pyrotechnik
KW - Sprengplattieren
KW - Fallhammer
KW - Zünder
PY - 2022
AN - OPUS4-54689
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - X-ray hazards and radiation protection aspects in ultrashort laser processing
N2 - Ultrashort pulse laser micromachining at repetition rates of several hundreds of kHz allows a cost-effective high precision manufacturing, which makes this method attractive for many industrial applications. Upon exceeding a critical laser intensity, hard X-ray radiation is generated as a side effect. Even if the emitted X-ray dose per laser pulse is low, for currently available high-repetition-rate laser systems the accumulated X-ray dose becomes significant and radiation safety must be considered. Influences of the processing parameters are discussed and radiation protection aspects will be outlined
T2 - AKL’22 – International Laser Technology Congress
CY - Aachen, Germany
DA - 04.05.2022
KW - Ultrashort pulse laser processing
KW - X-ray emission
KW - Radiation protection
PY - 2022
AN - OPUS4-54805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chambers, M. S.
A1 - Hunter, R. D.
A1 - Hollamby, M. J.
A1 - Pauw, Brian Richard
A1 - Smith, A. J.
A1 - Snow, T.
A1 - Danks, A. E.
A1 - Schnepp, Z.
T1 - In Situ and Ex Situ X‑ray Diffraction and Small-Angle X‑ray Scattering Investigations of the Sol−Gel Synthesis of Fe3N and Fe3C
N2 - Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows:
Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide−nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phasepure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol−gel synthesis of Fe3C nanoparticles.
KW - Small-angle X-ray Scattering
KW - SAXS
KW - Diffraction
KW - XRD
KW - Scattering
KW - Sol-gel
KW - Iron nitride
KW - Nanoparticles
KW - Iron carbide
KW - Catalyst
KW - In-situ
KW - Ex-situ
KW - Synthesis
KW - Synchrotron
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548226
DO - https://doi.org/10.1021/acs.inorgchem.1c03442
VL - 61
IS - 18
SP - 6742
EP - 6749
PB - ACS Publications
CY - Washington
AN - OPUS4-54822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Hygienische Eigenschaften von additiv gefertigtem 1.4404 in Trinkwasser
N2 - Elektrochemische Messungen zur hygienischen Bewertung additiv gefertigter Bauteile werden diskutiert. Die Bewertung und Details des Werkstoffs werden beschrieben, Anwendungsbeispiele gezeigt.
T2 - 3. Fachtagung Werkstoffe und Additive Fertigung
CY - Dresden, Germany
DA - 11.05.2022
KW - Korrosion
KW - Trinkwasser
KW - Hygiene
KW - Additive Fertigung
PY - 2022
AN - OPUS4-54829
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - In-situ Prozessüberwachung in der additiven Fertigung von Metallen (PBF-LB /M) mittels TT und ET
N2 - Durch die additive Fertigung ergeben sich durch die nun mögliche wirtschaftliche Fertigung hochgradig individueller und komplexer metallischer Bauteile in kleinen Stückzahlen bis hinunter zum Einzelstück für viele Industriebereiche ganz neue Möglichkeiten.
Gleichzeitig entstehen jedoch neue Herausforderungen im Bereich der Qualitätssicherung, da sich auf statistischen Methoden beruhende Ansätze nicht anwenden lassen, ohne wiederum die Vorteile der Fertigung massiv einzuschränken.
Eine mögliche Lösung für dieses Problem liegt in der Anwendung verschiedener In-situ-Überwachungstechniken während des Bauprozesses. Jedoch sind nur wenige dieser Techniken kommerziell verfügbar und noch nicht so weit erforscht, dass die Einhaltung strenger Qualitäts- und Sicherheitsstandards gewährleistet werden kann. In diesem Beitrag stellen wir die Ergebnisse einer Studie über mittels L-PBF gefertigte Probekörper aus der Nickelbasis-Superlegierung Haynes 282 vor, bei denen die Bildung von Defekten durch lokale Variationen der Prozessparameter wie der Laserleistung provoziert wurde. Die Proben wurden in-situ mittels Thermographie, optischer Tomographie, Schmelzbadüberwachung und Wirbelstromprüfung sowie ex-situ mittels Computertomographie (CT) überwacht, mit dem Ziel, die Machbarkeit und die Aussichten der einzelnen Methoden für die zuverlässige Erkennung der Bildung relevanter Defekte zu bewerten.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Additive Manufacturing
KW - Thermografie
KW - Additive Fertigung
KW - Thermography
PY - 2022
AN - OPUS4-55851
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - In-situ Monitoring of PBF-LB/M by thermography, optical tomography, melt-pool-monitoring and eddy current
N2 - The formation of defects such as keyhole pores is a major challenge for the production of metal parts by Laser Powder Bed Fusion (LPBF). The LPBF process is characterized by a large number of influencing factors which can be hard to quantify. Machine Learning (ML) is a prominent tool to predict the outcome of complex processes on the basis of different sensor data. In this study, a ML model for defect prediction is created using thermographic image features as input data. As a reference, the porosity information calculated from an x-ray Micro Computed Tomography (µCT) scan of the produced specimen is used. Physical knowledge about the keyhole pore formation is incorporated into the model to increase the prediction accuracy. From the prediction result, the quality of the input data is evaluated and future demands on in-situ monitoring of LPBF processes are formulated.
T2 - AM Bench 2022
CY - Bethesda, Washingthon DC, USA
DA - 15.08.2022
KW - Additive Manufacturing
KW - Thermography
KW - Additive Fertigung
KW - Thermografie
PY - 2022
AN - OPUS4-55854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
A1 - Lehmann, Jens
T1 - Einfach und echt schnell - Der KorroPad Test
N2 - In diesem dritten Teil wird die KorroPad Prüfmethode vorgestellt und erläutert.
T2 - ISER Kursleiterfortbildung 2022
CY - Düsseldorf, Germany
DA - 26.09.2022
KW - Korrosion
KW - nichtrostender Stahl
KW - KorroPad
KW - Korrosionsprüfung
KW - Schnelltest
PY - 2022
AN - OPUS4-55858
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dudek, Gabriele
T1 - Benefits of Digitization
N2 - The presentation will address recent achievements through the introduction of a digital seal and outline the potential future framework for AI-assisted classification decisions in the area of explosives or pyrotechnics transportation.
T2 - International Group of experts on the explosion risks of Unstable Substances (IGUS)- Joint Meeting CIE/IGUS-EPP
CY - Madrid, Spain
DA - 20.04.2023
KW - Explosivstoffe
KW - Pyrotechnik
KW - Transportklassifizierung
KW - Digitalisierung
KW - Lagergruppenzuordnung
PY - 2023
AN - OPUS4-57410
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valdestilhas, Andre
A1 - Bayerlein, Bernd
A1 - Moreno Torres, Benjami
A1 - Zia, Ghezal Ahmad Jan
A1 - Muth, Thilo
T1 - The Intersection Between Semantic Web and Materials Science
N2 - The application and benefits of Semantic Web Technologies (SWT) for managing, sharing, and (re-)using of research data are demonstrated in implementations in the field of Materials Science and Engineering (MSE). However, a compilation and classification are needed to fully recognize the scattered published works with its unique added values. Here, the primary use of SWT at the interface with MSE is identified using specifically created categories. This overview highlights promising opportunities for the application of SWT to MSE, such as enhancing the quality of experimental processes, enriching data with contextual information in knowledge graphs, or using ontologies to perform specific queries on semantically structured data. While interdisciplinary work between the two fields is still in its early stages, a great need is identified to facilitate access for nonexperts and develop and provide user-friendly tools and workflows. The full potential of SWT can best be achieved in the long term by the broad acceptance and active participation of the MSE community. In perspective, these technological solutions will advance the field of MSE by making data FAIR. Data-driven approaches will benefit from these data structures and their connections to catalyze knowledge generation in MSE.
KW - Linked open data
KW - Materials science
KW - Ontology
KW - Semantic web
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575506
DO - https://doi.org/10.1002/aisy.202300051
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-57550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - In-situ monitoring of the laser powder bed fusion process by thermography, optical tomography and melt pool monitoring for defect detection
N2 - For the wide acceptance of the use of additive manufacturing (AM), it is required to provide reliable testing methods to ensure the safety of the additively manufactured parts. A possible solution could be the deployment of in-situ monitoring during the build process. However, for laser powder bed fusion using metal powders (PBF-LB/M ) only a few in-situ monitoring techniques are commercially available (optical tomography, melt pool monitoring) but not researched to an extent that allows to guarantee the adherence to strict quality and safety standards.
In this contribution, we present results of a study of PBF-LB/M printed parts made of the nickel-based superalloy Haynes 282. The formation of defects was provoked by local variations of the process parameters and monitored by thermography, optical tomography and melt pool monitoring. Afterwards, the defects were characterized by computed tomography (CT) to identify the detection limits of the used in-situ techniques.
T2 - LiM Conference 2023 - Lasers in Manufacturing
CY - Munich, Germany
DA - 26.06.2023
KW - Thermography
KW - High temperature alloys
KW - Additive Manufacturing
KW - PBF-LB/M
PY - 2023
AN - OPUS4-57947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Automation of machine learning driven interatomic potential generation for predicting vibrational properties
N2 - Investigating the phononic properties is beneficial for predicting low thermal conductivity thermoelectric materials.1–3 Employing density functional theory4 takes many calculation steps and consumes a lot of computational resources.5,6 Using machine learning driven interatomic potentials (MLIP, e.g., Gaussian approximation potential,8 GAP) opens up a faster route to phonons7 but in most cases, the potentials are specifically tailored for a certain compound. In this work, we automate the generation of such MLIPs in a Python code-based workflow, based on the automation tools atomate29 and pymatgen10 which combines the automatic DFT computations with the automated fitting of GAPs. Automation enables easier testing, benchmarking and validation.11 We aim to provide the workflow-generated potentials for storage in databases.
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Ireland
DA - 03.07.2023
KW - Interatomic potentials
KW - Machine learning
KW - Phonons
KW - Thermoelectrics
PY - 2023
AN - OPUS4-57932
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Quantum chemical bonding analysis of functional materials using LOBSTER and automated workflows
N2 - A talk on how to use LOBSTER and automated workflows (supported by LobsterPy, atomate2 and more) to do quantum chemical bonding analysis for (functional) materials design.
T2 - Gastvortrag Inorganic Chemistry Laboratory, University of Oxford
CY - Oxford, UK
DA - 04.05.2023
KW - Chemical bonding
KW - Automated workflows
KW - Functional materials
PY - 2023
AN - OPUS4-57933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Workflows and automation (lecture/tutorial)
N2 - A lecture and tutorial on how to use workflows and automation methods for quantum chemical calculations.
T2 - Invited lecture
CY - Oxford, UK
DA - 28.04.2023
KW - Workflows
KW - Automation
KW - Quantum chemical bonding analysis
PY - 2023
AN - OPUS4-57934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schilling, Markus
T1 - Tensile Test Ontology (TTO)
N2 - This is the stable version 2.0.1 of the PMD ontology module of the tensile test (Tensile Test Ontology - TTO) as developed on the basis of the 2019 standard ISO 6892-1: Metallic materials - Tensile Testing - Part 1: Method of test at room temperature.
The TTO was developed in the frame of the PMD project. The TTO provides conceptualizations valid for the description of tensile test and corresponding data in accordance with the respective standard. By using TTO for storing tensile test data, all data will be well structured and based on a common vocabulary agreed on by an expert group (generation of FAIR data) which will lead to enhanced data interoperability. This comprises several data categories such as primary data, secondary data and metadata. Data will be human and machine readable. The usage of TTO facilitates data retrieval and downstream usage. Due to a close connection to the mid-level PMD core ontology (PMDco), the interoperability of tensile test data is enhanced and data querying in combination with other aspects and data within the broad field of material science and engineering (MSE) is facilitated.
The TTO class structure forms a comprehensible and semantic layer for unified storage of data generated in a tensile test including the possibility to record data from analysis, re-evaluation and re-use. Furthermore, extensive metadata allows to assess data quality and reproduce experiments. Following the open world assumption, object properties are deliberately low restrictive and sparse.
KW - Ontology
KW - Tensile Test
KW - Digitalization
KW - Plattform MaterialDigital
KW - Structured Data
PY - 2023
UR - https://github.com/MarkusSchilling/application-ontologies/blob/479311832819af695a2c64fa8eb772f2da398061/tensile_test_ontology_TTO/pmd_tto.ttl
UR - https://github.com/materialdigital/core-ontology/blob/59f5727b0437ceea5e3d9fcb8fcd0ac211e92cc3/pmd_tto.ttl
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-57935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bustamante, Joana
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Ueltzen, Katharina
A1 - George, Janine
T1 - Thermodynamic and Thermoelectric Properties of the Canfieldite, (Ag8SnS6 ), in the Quasi-Harmonic Approximation
N2 - Argyrodite-type materials have lately sparked a lot of research interest due to their thermoelectric properties.One promising candidate is canfieldite (Ag8SnS6), which has a Pna21 orthorhombic crystal structure at room temperature (RT). Recently, a new low-temperature (LT) phase transition of canfieldite at 120K has been found. Here, we investigate structural, vibrational and thermodynamic properties of Ag8SnS6 at room- and low-temperature employing density functional theory (DFT) and lattice dynamics computations. Thermal properties calculations were based on the quasi-harmonic approximation (QHA) as implemented in phonopy. We achieve good agreement with experiments. Thermal properties such as the constant-pressure heat capacity (Cp) and thermal conductivity are very close to experimental measurements. Furthermore, we compared RT and LT Ag8SnS6 Grüneisen parameters with argyrodites analogues, Ag8XS6 (X = Sn, Si, Ge), to arrive at an improved
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Ireland
DA - 03.07.2023
KW - Thermoelectric materials
KW - DFT
KW - QHA
KW - Grüneisen parameter
PY - 2023
AN - OPUS4-57887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Benefits of novel tools open to Industry from Open Innovation Testbeds. Effects of harmonised procedures in (digital) Tribology
N2 - The work on Tribology, digitalisation, and the harmonised procedures developed in i-TRIBOMAT Open Innovation Testbed was presented. The project develops procedures and shares ideas on how to deal with characterisation techniques and provide services to end users in different places and locations, which is realised by adopting a common and widely agreed procedures. i-TRIBOMAT is active also via YouTube platform to enhance communication and spread the word amongst the interested parties and society.
T2 - Workshop of NanoMECommons project: "Materials characterisation challenges to support the industry transition in the digital era"
CY - Online meeting
DA - 13.12.2021
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Interoperability
KW - Harmonisation
KW - Green Deal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548909
DO - https://doi.org/10.5281/zenodo.6339985
SP - 14
EP - 17
AN - OPUS4-54890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Walter, Astrid
A1 - Costard, René
A1 - Dengel, Jörg
A1 - Lohrer, Christian
T1 - Normung Explosivstoffe & Pyrotechnik - Quo vadis?
N2 - Dieser Beitrag gibt einen Überblick über die kürzlich abgeschlossenen und laufenden Normungsaktivitäten im Bereich der zivilen Explosivstoffe und pyrotechnischen Gegenstände. Ein Fokus dieses Beitrags liegt auf den Themen elektronische Zündsysteme, vor-Ort hergestellte Explosivstoffe und auf dem aktuellen Entwurf eines Normungsauftrags im Bereich der pyrotechnischen Gegenstände. Des Weiteren wird auf den Entwicklungsprozess und die Bedeutung der Normung im Allgemeinen eingegangen.
T2 - 43. Informationsveranstaltung Sprengtechnik
CY - Siegen, Germany
DA - 22.04.2022
KW - Normung
KW - Explosivstoffe
KW - Zünder
KW - Pyrotechnik
KW - Feuerwerk
PY - 2022
SN - 0941-4584
VL - 44
IS - 2
SP - 8
EP - 16
PB - Deutscher Sprengverband
CY - Siegen
AN - OPUS4-55569
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
T1 - Meeting the challenge of thermal joining of steel and aluminum using a new approach based on melt displacement by electromagnetic forces
N2 - Environmental protection, resource conservation and CO2 reduction require new joining concepts for effective multi-material design in automotive lightweight construction. The thermal joining of dissimilar materials, especially the combination of aluminum alloys and steel, is associated with difficulties. Different material properties, such as melting point and coefficient of thermal expansion, complicate joining processes. Furthermore, the insolubility between these materials results in the formation of intermetallic phases. These brittle phases reduce the load-bearing capacity and quality of the joints. The thickness of the intermetallic phases should not reach the critical value of 10 μm to ensure good mechanical properties of the joint. It is known that a two-phase reaction layer consisting of Al5Fe2 and Al3Fe (also known as Al13Fe4) forms at the interface between solid steel and liquid aluminum. Due to high cooling rates, as it is the case in laser beam welding, metastable intermetallic compounds can form different from the equilibrium state. The formation of the intermetallic reaction layer is a diffusion-controlled process. So, it is only possible to control the growth of these phases. This problem has led to use joining methods that do not require the melting of both joining partners. A promising joining method is laser beam welding-brazing, whereby only one joining partner is melted and wets the solid joining partner. Conventional laser beam welding-brazing only results in material-fit joints and often requires the use of expensive filler materials. An additional form-fit could optimize the mechanical performance of the joint. For this reason, a new joining method for overlap configurations of dissimilar materials was developed. A laser beam melts the lower joining partner through a cavity of the upper joining partner. The created melt pool is moved upwards into the cavity of the upper joining partner due to contactless induced Lorentz forces of an AC-magnetic system. The displaced melt creates a form- and material-fit joint after solidification. The advantage of this joining technology is the absence of filler materials, flux agents and expensive auxiliary joining elements.
T2 - 5th International Conference Hybrid 2022 - Materials and Structures
CY - Leoben, Austria
DA - 20.07.2022
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Electromagnetic forces
KW - Steel and aluminium
PY - 2022
AN - OPUS4-55534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
ED - Hausmann, J. M.
T1 - Meeting the challenge of thermal joining of steel and aluminum using a new approach based on melt displacement by electromagnetic forces
N2 - Environmental protection, resource conservation and CO2 reduction require new joining concepts for effective multi-material design in automotive lightweight construction. The thermal joining of dissimilar materials, especially the combination of aluminum alloys and steel, is associated with difficulties. Different material properties, such as melting point and coefficient of thermal expansion, complicate joining processes. Furthermore, the insolubility between these materials results in the formation of intermetallic phases. These brittle phases reduce the load-bearing capacity and quality of the joints. The thickness of the intermetallic phases should not reach the critical value of 10 μm to ensure good mechanical properties of the joint. It is known that a two-phase reaction layer consisting of Al5Fe2 and Al3Fe (also known as Al13Fe4) forms at the interface between solid steel and liquid aluminum. Due to high cooling rates, as it is the case in laser beam welding, metastable intermetallic compounds can form different from the equilibrium state. The formation of the intermetallic reaction layer is a diffusion-controlled process. So, it is only possible to control the growth of these phases. This problem has led to use joining methods that do not require the melting of both joining partners. A promising joining method is laser beam welding-brazing, whereby only one joining partner is melted and wets the solid joining partner. Conventional laser beam welding-brazing only results in material-fit joints and often requires the use of expensive filler materials. An additional form-fit could optimize the mechanical performance of the joint. For this reason, a new joining method for overlap configurations of dissimilar materials was developed. A laser beam melts the lower joining partner through a cavity of the upper joining partner. The created melt pool is moved upwards into the cavity of the upper joining partner due to contactless induced Lorentz forces of an AC-magnetic system. The displaced melt creates a form- and material-fit joint after solidification. The advantage of this joining technology is the absence of filler materials, flux agents and expensive auxiliary joining elements.
T2 - 5th International Conference Hybrid 2022 - Materials and Structures
CY - Leoben, Austria
DA - 20.07.2022
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Electromagnetic forces
KW - Steel and aluminium
PY - 2022
SN - 978-3-88355-426-6
SP - 6
EP - 8
PB - Deutsche Gesellschaft für Materialkunde (DGM)
CY - Sankt Augustin
AN - OPUS4-55536
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Räpke, Toni
T1 - Geometrie- und Prozesseinflüsse auf lokale Bauteileigenschaften in der metallischen additiven Fertigung mittels Laserstrahlschmelzen
N2 - Die mechanischen Eigenschaften und die Standardparametersätze werden im additiven Fertigungsverfahren Laser Powder Bed Fusion (L-PBF) zumeist an Körpern ermittelt, die unter festen Randbedingungen gefertigt werden. In der Literatur wird allerdings von verschiedenen Autoren auf einen Einfluss von Geometrie und Prozess auf die resultierenden Eigenschaften hingewiesen [1, 2, 3]. Aufgrund des häufig großen Komplexitätsgrads von L-PBF Bauteilen und Prozessen, ist eine Abweichung angenommener Eigenschaften daher nicht auszuschließen. Das kann besonders für tragende und sicherheitsrelevante Komponenten kritisch sein und ist eine Herausforderung für die Qualitätssicherung. Aufwendige Trial-and-Error Versuche sind zumeist die Folge. Ein einheitliches und umfassendes Verständnis der Einflussfaktoren auf die resultierenden Eigenschaften im L-PBF Prozess ist zum aktuellen Stand nicht vorhanden.
In diesem Vortrag werden erste Ergebnisse einer Studie vorgestellt, in der systematisch die Bandbreite möglicher Defekt- und Mikrostrukturvariationen in L-PBF Bauteilen am Beispiel der Nickelbasislegierung Haynes 282 untersucht wird. Aufbauend auf einer modellbasierten Beschreibung des lokalen Wärmehaushalts wurden Versuchspläne entwickelt, die eine Vielzahl möglicher Prozess- und Geometriekonfigurationen realer Anwendungen abbilden können. Zur Untersuchung des Geometrieeinflusses wurden typische Geometrieelemente komplexer Strukturen und deren Ausprägungen identifiziert. Prozessseitig wurden die Position im Bauraum, Schwankungen der Laserleistung, die Zwischenlagenzeit und die Belichtungsstrategie innerhalb der Schicht als typische Faktoren berücksichtigt. Die Zwischenlagenzeit bildet dabei Variationen im Bauraumfüllgrad ab. Die Belichtungsstrategie untersucht Effekte wie die Zwischenvektorzeit (engl. inter vector time, IVT) oder die lokale Vektorlänge. Die verschiedenen Konfigurationen wurden metallografisch bewertet. Die bisherigen Ergebnisse können einen Einfluss der Geometrie und des Prozesses auf die Defektbildung und die Mikrostruktur in L-PBF Bauteilen aufzeigen. Durch prozessbegleitende thermografische in situ Messungen konnte außerdem eine Abhängigkeit von lokalen und globalen Temperaturfeldern identifiziert werden. Die Erkenntnisse zeigen zudem, dass der geometrische Einfluss auf den lokalen Wärmehaushalt von Anordnung, Gestalt und Dimensionen der zweidimensionalen Belichtungsbereiche über die Aufbauhöhe abhängt. Das gewonnene Verständnis soll in die Entwicklung von Konstruktionsrichtlinien und Prüfkörpern einfließen, um Variationen lokaler Bauteileigenschaften in der zukünftigen Bauteil- und Prozessauslegung berücksichtigen zu können.
T2 - 3. Fachtagung Werkstoffe und Additive Fertigung 2022
CY - Dresden, Germany
DA - 11.05.2022
KW - Additive Fertigung
KW - L-PBF
PY - 2022
AN - OPUS4-55516
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heuser, Lina
A1 - Nofz, Marianne
T1 - Alkali and alkaline earth zinc and lead borate glasses: Structure and properties
N2 - Low melting Li2O-PbO-B2O3, Me2O-ZnO-B2O3, Me = Li, Na, K, Rb and CaO-ZnO-B2O3 glasses were studied with Raman and infrared spectroscopies to advance the structural understanding of zinc borate glasses as potential candidates for substitution of lead containing glasses. Although the effect of type of alkali ions on the number (N4) of fourfold coordinated boron (B4) in the glasses is small, the alkali ions direct the type of borate groups, i.e., pentaborate in lithium, sodium, and calcium zinc borate glasses, as well as diborate in potassium and rubidium containing ones. Both groups were simultaneously found in Li2O-PbO-B2O3. Alkali ions are mainly responsible for the formation of B4-units and metaborate. Zinc ions favorably compensate non-bridging oxygen and partially form ZnO4. With decreasing N4 and field strength of the alkali ions the atomic packing density, glass transition temper ature and Young’s Modulus also decrease. The coefficient of thermal expansion increases with decreasing N4.
KW - Raman spectroscopy
KW - IR spectroscopy
KW - Alkali zinc borate glasses
KW - Lead borate glasses
KW - Physical properties
KW - Young’s Modulus
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556109
DO - https://doi.org/10.1016/j.nocx.2022.100109
SN - 2590-1591
VL - 15
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thekkeppat, N. P.
A1 - Bhattacharya, Biswajit
A1 - Tothadi, S.
A1 - Ghosh, S.
T1 - Mechanically flexible crystals of styryl quinoline derivatives
N2 - Herein, we report three crystals of styryl quinoline derivatives. All these three crystals are mechanically flexible crystals, isostructural and also all of them comply with the common underlying features for elas- tic flexibility like absence of slip plane, criss-cross packing arrangement of neighbouring tapes, presence of weak and dispersive interactions such as halogen bonds, hydrogen bonds etc. The interactions facilitate easy movement of molecules under application of pressure thereby imparting elasticity. Further, the crys- tals were found to be blue light emitting making them promising candidates for optical waveguides. The optical properties were combined with flexibility by using crystal engineering approach towards achiev- ing various applications such as flexible OLEDs, optical waveguides, flexible optoelectronics etc.
KW - Mechanical flexibility
KW - Halogen bond
KW - Fluorescence
PY - 2022
DO - https://doi.org/10.1016/j.molstruc.2022.133293
SN - 0022-2860
VL - 1265
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schumacher, David
A1 - Waske, Anja
T1 - XCT data of metallic feedstock powder with pore size analysis
N2 - X-Ray computed tomography (XCT) scan of 11 individual metallic powder particles, made of (Mn,Fe)2(P,Si) alloy. The data set consists of 4 single XCT scans which have been stitched together [3] after reconstruction. The powder material is an (Mn,Fe)2(P,Si) alloy with an average density of 6.4 g/cm³. The particle size range is about 100 - 150 µm with equivalent pore diameters up to 75 µm. The powder and the metallic alloy are described in detail in [1, 2].
KW - Additive Manufacturing
KW - Feedstock powder
KW - Powder Characterization
KW - X-Ray Computed Tomography
PY - 2022
DO - https://doi.org/10.5281/zenodo.5796487
PB - Zenodo
CY - Geneva
AN - OPUS4-55556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paskin, A.
A1 - Couasnon, T.
A1 - Perez, J. P. H.
A1 - Lobanov, S. S.
A1 - Blukis, R.
A1 - Reinsch, Stefan
A1 - Benning, L. G.
T1 - Nucleation and Crystallization of Ferrous Phosphate Hydrate via an Amorphous Intermediate
N2 - The fundamental processes of nucleation and crystallization are widely observed in systems relevant to material synthesis and biomineralization; yet most often, their mechanism remains unclear. In this study, we unravel the discrete stages of nucleation and crystallization of Fe3(PO4)2·8H2O (vivianite). We experimentally monitored the formation and transformation from ions to solid products by employing correlated, time-resolved in situ and ex situ approaches. We show that vivianite crystallization occurs in distinct stages via a transient amorphous precursor phase. The metastable amorphous ferrous phosphate (AFEP) intermediate could be isolated and stabilized. We resolved the differences in bonding environments, structure, and symmetric changes of the Fe site during the transformation of AFEP to crystalline vivianite through synchrotron X-ray absorption spectroscopy at the Fe K-edge. This intermediate AFEP phase has a lower water content and less distorted local symmetry, compared to the crystalline end product vivianite. Our combined results indicate that a nonclassical, hydration-induced nucleation and transformation driven by the incorporation and rearrangement of water molecules and ions (Fe2+ and PO4 3−) within the AFEP is the dominating mechanism of vivianite formation at moderately high to low vivianite supersaturations (saturation index ≤ 10.19). We offer fundamental insights into the aqueous, amorphous-to-crystalline transformations in the Fe2+−PO4 system and highlight the different attributes of the AFEP, compared to its crystalline counterpart.
KW - Nucleation
KW - Crystallization
KW - Vivianite
KW - Ferrous phosphate hydrate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580696
DO - https://doi.org/10.1021/jacs.3c01494
SN - 0002-7863
VL - 145
IS - 28
SP - 15137
EP - 15151
PB - ACS Publications
AN - OPUS4-58069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madeja, B.
A1 - Gebauer, D.
A1 - Marsiske, M. R.
A1 - Ott, A.
A1 - Rückel, M.
A1 - Rosenberg, R.
A1 - Baken, A.
A1 - Stawski, Tomasz M.
A1 - Fernandez-Martinez, A.
A1 - Van Driessche, A.E.S.
A1 - Cölfen, H.
A1 - Kellermeier, M.
T1 - New insights into the nucleation of portlandite and the effects of polymeric additives
N2 - The crystallization of calcium hydroxide (Ca(OH)2, CH, portlandite) is a key process during the early stages of cement hydration. In the present work, we have revisited the formation of this mineral through nucleation and growth from supersaturated aqueous solutions, in the light of the currently emerging picture of multistage “non-classical” crystallization. To that end, we developed a titration-based assay, in which stock solutions of both relevant ions are added simultaneously into a reservoir, where supersaturation increases slowly at constant stoichiometry until nucleation occurs. This procedure allows both pre- and early post-nucleation phenomena to be analyzed quantitatively. Complementarily, the early stages of portlandite mineralization were probed by various advanced characterization techniques, including cryo-transmission electron microscopy (cryo-TEM), in-situ small-angle X-ray scattering (SAXS), pair distribution function (PDF) analysis of high-energy X-ray scattering (HEXS) data, and analytical ultracentrifugation (AUC). The experimental data show that the formation of calcium hydroxide starts with the association of ions into complexes and clusters, which subsequently coalesce to form amorphous nanoparticles – much like what has been observed in the case of calcium carbonate and other prominent minerals. Subsequently, these particles aggregate and build networks, which eventually transform into hexagonal Ca(OH)2 crystals. The presence of a soluble polycarboxylate – as a known inhibitor of portlandite crystallization – does not change the main characteristics of this multistep nucleation pathway, but it proved capable of significantly extending the lifetime of the amorphous intermediate phase and thus delaying the transition to the final crystalline phase. Our observations confirm the notion that “non-classical” crystallization is a much more common phenomenon than initially believed – and that, for minerals forming in aqueous environments, it may actually be the rule rather than the exception.
KW - General Materials Science
KW - Building and Construction
PY - 2023
DO - https://doi.org/10.1016/j.cemconres.2023.107258
SN - 0008-8846
VL - 173
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-58162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zare Pakzad, S.
A1 - Nasr Esfahani, M.
A1 - Tasdemir, Z.
A1 - Wollschläger, Nicole
A1 - Li, T.
A1 - Li, X.
A1 - Yilmaz, M.
A1 - Leblebici, Y.
A1 - Erdem Alaca, B.
T1 - Nanomechanical Modeling of the Bending Response of Silicon Nanowires
N2 - Understanding the mechanical behavior of silicon nanowires is essential for the implementation of advanced nanoscale devices. Although bending tests are predominantly used for this purpose, their findings should be properly interpreted through modeling. Various modeling approaches tend to ignore parts of the effective parameter set involved in the rather complex bending response. This oversimplification is the main reason behind the spread of the modulus of elasticity and strength data in the literature. Addressing this challenge, a surface-based nanomechanical model is introduced in this study. The proposed model considers two important factors that have so far remained neglected despite their significance: (i) intrinsic stresses composed of the initial residual stress and surface-induced residual stress and (ii) anisotropic implementation of surface stress and elasticity. The modeling study is consolidated with molecular dynamics-based study of the native oxide surface through reactive force fields and a series of nanoscale characterization work through in situ threepoint bending test and Raman spectroscopy. The treatment of the test data through a series of models with increasing complexity demonstrates a spread of 85 GPa for the modulus of elasticity and points to the origins of ambiguity regarding silicon nanowire properties, which are some of the most commonly employed nanoscale building blocks. A similar conclusion is reached for strength with variations of up to 3 GPa estimated by the aforementioned nanomechanical models. Precise consideration of the nanowire surface state is thus critical to comprehending the mechanical behavior of silicon nanowires accurately. Overall, this study highlights the need for a multiscale theoretical framework to fully understand the size-dependent mechanical behavior of silicon nanowires, with fortifying effects on the design and reliability assessment of future nanoelectromechanical systems.
KW - Silicon nanowires
KW - Native oxide
KW - Surface stress
KW - Surface elasticity
KW - Mechanical behavior
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581676
DO - https://doi.org/10.1021/acsanm.3c02077
SP - 1
EP - 14
PB - ACS Publications
AN - OPUS4-58167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ivanov, V.V.
A1 - Tielemann, Christopher
A1 - Avramova, K.
A1 - Reinsch, Stefan
A1 - Tonchev, V.
T1 - Modelling crystallization: When the normal growth velocity depends on the supersaturation
N2 - The crystallization proceeds by the advance of the crystal faces into the disordered phase at the expense of the material excess, the supersaturation. Using a conservation constraint for the transformation ratio α∈[0,1] as complementing the rescaled supersaturation to 1 and a kinetic law for the normal growth velocity as function of the supersaturation raised to power g, the growth order, we derive an equation for the rate of transformation dα/dt. We integrate it for the six combinations of the three spatial dimensions D = 1, 2, 3 and the two canonical values of g = 1, 2 towards obtaining expressions for αDg. The same equation, with g = 1 and D = n (n is the so called Avrami exponent) is obtained when taking only the linear in α term from the Taylor’s expansion around α = 0 of the model equation of Johnson-Mehl-Avrami-Kolmogorov (JMAK). We verify our model by fitting datasets of α21 and α31 (from α = 0 to αupper = 0.999) with JMAK to obtain from the fit n = 1.725, 2.43, resp. We show
further how the values of n depend on the value of αupper to which the fit is performed starting always from 0. Towards building a validation protocol, we start with validating α21 with published results.
KW - Crystallization
KW - Supersaturation
KW - Growth kinetics
KW - Growth rate
KW - JMAK model
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581706
DO - https://doi.org/10.1016/j.jpcs.2023.111542
SN - 0022-3697
VL - 181
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-58170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cios, G.
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
A1 - Dan, L.
A1 - Bala, P.
T1 - Mapping of lattice distortion in martensitic steel—Comparison of different evaluation methods of EBSD patterns
N2 - To visualize the varying tetragonal distortions in high carbon martensitic steels by EBSD, two different approaches have been applied on backscattered Kikuchi diffraction (BKD) patterns. A band-edge refinement technique called Refined Accuracy (RA) (Oxford Instruments) is compared with a technique called Pattern Matching (PM), which optimizes the fit to a simulated BKD signal. RA distinguishes between hypothetical phases of different fixed 𝑐∕𝑎, while PM determines a best fitting continuous 𝑐∕𝑎 by projective transformation of a master pattern. Both techniques require stored BKD patterns.
The sensitivity of the 𝑐∕𝑎-determination was tested by investigating the microstructure of a ferritic steel with an expected 𝑐∕𝑎 = 1. The influence of the Kikuchi pattern noise on 𝑐∕𝑎 was compared for a single or 40 averaged frames per measuring point, and turned out to be not significant. The application of RA and PM on the martensitic microstructure delivered qualitatively similar maps of 𝑐∕𝑎. The comparison of RA and PM shows that RA is suitably fast and precise during mapping the martensite 𝑐∕𝑎 ratio in analyses of high carbon martensite, especially for fast initial surveys. As RA leads quantitatively to higher noise in 𝑐∕𝑎, the PM analysis can be used for higher precision results.
KW - EBSD
KW - Steel
KW - Martensite
KW - Tetragonality
KW - Strain
PY - 2023
DO - https://doi.org/10.1016/j.ultramic.2023.113824
VL - 253
SP - 1
EP - 11
AN - OPUS4-58158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, A.
A1 - Wegener, T.
A1 - Degener, Sebastian
A1 - Bolender, A.
A1 - Möller, N.
A1 - Niendorf, T.
T1 - Experimental Analysis of the Stability of Retained Austenite in a Low‐Alloy 42CrSi Steel after Different Quenching and Partitioning Heat Treatments
N2 - Quenching and partitioning (Q&P) steels are characterized by an excellent combination of strength and ductility, opening up great potentials for advanced lightweight components. The Q&P treatment results in microstructures with a martensitic matrix being responsible for increased strength whereas interstitially enriched metastable retained austenite (RA) contributes to excellent ductility. Herein, a comprehensive experimental characterization of microstructure evolution and austenite stability is carried out on a 42CrSi steel being subjected to different Q&P treatments. The microstructure of both conditions is characterized by scanning electron microscopy as well as X‐ray diffraction (XRD) phase analysis. Besides macroscopic standard tensile tests, RA evolution under tensile loading is investigated by in situ XRD using synchrotron and laboratory methods. As a result of different quenching temperatures, the two conditions considered are characterized by different RA contents and morphologies, resulting in different strain hardening behaviors as well as strength and ductility values under tensile loading. In situ synchrotron measurements show differences in the transformation kinetics being rationalized by the different morphologies of the RA. Eventually, the evolution of the phase specific stresses can be explained by the well‐known Masing model.
KW - Condensed Matter Physics
KW - General Materials Science
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581618
DO - https://doi.org/10.1002/adem.202300380
SN - 1438-1656
VL - 25
IS - 17
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-58161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - 3D Imaging and residual stress analysis of additively manufactured materials
N2 - The focus of the presentation focus will be on 3D imaging by means of X-ray Computed Tomography (XCT) at the lab and at synchrotron, and the non-destructive residual stress (RS) characterization by diffraction of additively manufactured (AM) materials in BAM (Berlin, Germany). The manufacturing defects and high RS are inherent of AM techniques and affect structural integrity of the components. Using XCT the defects size and shape distribution as well as geometrical deviations can be characterized, allowing the further optimization of the manufacturing process. Diffraction-based RS analysis methods using neutron and synchrotron X-rays at large scale facilities offer the possibility to non-destructively spatially resolve both surface and bulk RS in complex components and track their changes following applied thermal or mechanical loads.
T2 - The International Symposium on Nondestructive Characterization of Materials 2023
CY - Zurich, Switzerland
DA - 15.08.2023
KW - Additive manufacturing
KW - Residual stress
KW - X-ray computed tomography
PY - 2023
AN - OPUS4-58113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tran, T.
A1 - Kodisch, C.
A1 - Schöttle, M.
A1 - Pech May, Nelson Wilbur
A1 - Retsch, M.
T1 - Characterizing the thermal diffusivity of single, micrometer-sized fibers via high-resolution lock-in thermography
N2 - Many advanced materials consist of fibers. They are used as nonwovens, fabrics, or in composite materials. Characterization of individual fibers allows us to predict resulting material properties. We present a measurement setup and analysis software to characterize individual, micrometer-sized fibers fast and reliably. The setup is based on the lock-in thermography principle. Thermal diffusivity values of seven reference samples agree very well with previously reported values. We use our setup to investigate critical measurement parameters like excitation frequency, excitation power, pixel size, and fiber orientation. Our results show that fibers with subpixel diameters can be measured even if they are not aligned. However, special care has to be taken to choose an adequate excitation power. Measurements at high intensities can underestimate thermal diffusivity even though the raw data looks reasonable. By automatically measuring at different excitation powers, our setup solves this issue.
KW - Surfaces, coatings and films
KW - Physical and theoretical chemistry
KW - General energy
KW - Electronic, optical and magnetic materials
PY - 2022
DO - https://doi.org/10.1021/acs.jpcc.2c04254
SN - 1932-7455
VL - 126
IS - 32
SP - 14003
EP - 14010
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-58128
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wilke, Olaf
T1 - Harmonised test standard EN 16516 - common approach for all building products for interiors
N2 - The presentation gives general information about the European Standard EN 16516 “Construction products – Assessment of release of dangerous substances – Determination of emissions into indoor air”. This test standard was developed based on the mandate M/366 of the European commission and is a horizontal reference method for the determination of volatile organic compounds (VOC) from different classes of construction (building) products. Specific test conditions are to be selected by the product TCs (technical committees) in a way that a product is tested under its intended condition of use.
The test is based on the use of emission test chambers which are operated at constant air change rate and climate (23°C, 50 % r.h.) over 28 days. The standard defines the conditions and requirements for the measurement including loading factor, air change rate, sampling, analysis and calculation of emission rates of the substances. A 30 m³ reference room is described which is used to calculate air concentrations from the determined emission rates.
The standard EN 16516 enables the evaluation of construction products regarding their emissions into indoor air under defined and comparable conditions. The evaluation includes the determination of identified target compounds, non-identified target compounds, volatile carcinogenic compounds and the sum values TVOC, TSVOC and R.
T2 - UBA Conference - Limiting health impacts of construction products regarding VOC
CY - Online meeting
DA - 20.04.2021
KW - Building products
KW - EN 16516
KW - Emisson testing
KW - Construction products
PY - 2021
AN - OPUS4-58079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Kalinka, Gerhard
A1 - Loose, Florian
T1 - Carbon fibre composites exemplarily research at BAM
N2 - Lightweighting as a cross-cutting technology contributes significantly to achieve the European Green Deal goals. Based on, but not limited to, advanced materials and production technologies, the demand for natural resources and CO2 emmissions are reduced by lightweighting during production, as well as use phase. Therefore, lightweighting is a crucial transformation technology assisting in decoupling economic growth from resource consumption. In this manner, lightweighting contributes significantly as a key technology of relevance for many industrial sectors such as energy, mobility, and infrastructure, towards resource efficiency, climate action and economic strength, as well as a resilient Europe. To strengthen international partnerships, addressing global issues of today at the edge of science with high performance lightweight material based on carbon fibers, an overview about the BAM expertise in carbon fiber reinforced materials is given.
T2 - Meeting KCarbon
CY - Berlin, Germany
DA - 15.06.2023
KW - Lightweighting
KW - Carbon Fibers
KW - Recycling
KW - Push-out Test
KW - multi scale testing
PY - 2023
AN - OPUS4-58094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilrich, Cordula
T1 - Ist jeder Gefahrstoff gefährlich?
N2 - Die Begriffe gefährlicher Stoff und Gefahrstoff werden häufig nicht unterschieden – in vielen Fällen resultieren aber durch den Kontext auch keine Missverständnisse. Tatsächlich bestehen aber Unterschiede – sowohl inhaltlich als auch bezüglich des Rechtsbereichs, der jeweils für sie gilt.
Stoffe sind gefährlich, wenn sie den Kriterien der CLP-Verordnung für physikalische Gefahren, Gesundheitsgefahren oder Umweltgefahren entsprechen. Sie werden dann im Sinne der CLP-Verordnung entsprechend eingestuft und es ergeben sich Pflichten bezüglich des Inverkehrbringens innerhalb der EU.
Gefahrstoffe sind in der Gefahrstoffverordnung definiert. Sie beinhalten die gefährlichen Stoffe und weitere nicht notwendigerweise als gefährlich eingestufte Stoffe. Das Ziel ist vor allem der Schutz von Beschäftigten bei Tätigkeiten mit Gefahrstoffen – es handelt sich also um eine Arbeitsschutzvorschrift.
Dieser Aufsatz stellt gefährliche Stoffe in ihrem Kontext vor, gibt einen Überblick über die Prinzipien und Rechtsfolgen sowie Hinweise auf weiterführende Informationen und stellt ihnen die Gefahrstoffe gegenüber.
KW - Chemikalienrecht
KW - CLP-Verordnung
KW - Gefährlicher Stoff
KW - Gefahrstoff
KW - Gefahrstoffverordnung
KW - Gefahrstoffrecht
KW - REACH
KW - Sicherheitsdatenblatt
KW - SDB
PY - 2023
UR - https://beck-online.beck.de/?vpath=bibdata/zeits/ARP/2023/cont/ARP.2023.H06.NAMEINHALTSVERZEICHNIS.htm
SN - 2698-3710
VL - 2023
IS - 6
SP - 162
EP - 167
PB - C.H. Beck
CY - München
AN - OPUS4-57736
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Explosivstoffe & Pyrotechnik – Neues von der Normung und den benannten Stellen
N2 - Überblick über aktuelle Normungsarbeiten im CEN/TC 212 (Pyrotechnik) und CEN/TC 321 (Zivile Explosivstoffe) gemäß Normungsauftrag der EU-KOM. Weiterhin Bericht über Aktivitäten im Forum der benannten Stellen nach 2013/29/EU (Pyrotechnik) und 2014/28/EU (Zivile Explosivstoffe) und Auswertung Open Space-Diskussionen der Veranstaltung.
T2 - 15. Informationsveranstaltung "Sprengstoffe und Pyrotechnik"
CY - Berlin, Germany
DA - 19.06.2023
KW - Pyrotechnik
KW - Explosivstoffe
KW - Bescheide
KW - Zertifizierung
PY - 2023
AN - OPUS4-57742
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - John, Elisabeth
A1 - Lothenbach, Barbara
ED - Carter, C. B.
T1 - Cement hydration mechanisms through time – a review
N2 - In this article the progress of the research on cement hydration mechanisms is critically reviewed, starting with the work of Le Chatelier and Michaelis during the late 19th century. Proposed mechanisms are discussed in the light of experimental data to highlight the role of new or improved analytical techniques. The focus of this article lies on the dormant period and the silicate reaction.
Today many of the mechanisms proposed throughout time cannot withstand experimental evidence and need to be rejected, including the classical protective hydrate layer theory. However, it seems likely that hydrated surface species are involved in the mechanism. Theories that aim to explain the rate changes solely based on the nucleation and growth of portlandite can also not withstand experimental evidence. Nevertheless, the retardation of portlandite crystal growth through silicate ions is a relevant factor. Especially since it might present a mechanism for the nucleation of calcium silicate hydrate (C-S-H), backing up theories that propose C-S-H and portlandite to grow from the same nuclei.
Finally, an overview over facts, that are currently considered to be valid and hence need to be regarded in future mechanisms is given.
KW - Cement hydration
KW - Calcium silicate hydrate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577460
DO - https://doi.org/10.1007/s10853-023-08651-9
SN - 1573-4803
VL - 58
IS - 24
SP - 9805
EP - 9833
PB - Springer Science + Business Media B.V
CY - Dordrecht [u.a.]
AN - OPUS4-57746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - Failure Mechanisms Investigation by Means of in-situ Synchrotron Computed Tomography in Aluminum MMC-based Alloy Tailored for Additive Manufacturing
N2 - Synchrotron X-ray computed tomography (SXCT) at BAMline has been paired with in-situ tensile loading to monitor damage evolution in LPBF Metal Matrix Composite (MMC) 7017 Aluminium alloy + 3 wt% Zr + 0.5 wt% TiC. The processing of the material leads formation to different categories of Zr-rich inclusions, precipitates and defects. In-situ SXCT test disclosed the critical role of the pre-cracks in the reinforcement phases in the failure mechanisms of LPBF MMC. The damage was initiated from lack-of-fusion defects and cracks propagated through coalescence with other defects.
T2 - HZB Uer Meeting 2023
CY - Berlin, Germany
DA - 22.06.23
KW - Additive manufacturing
KW - BAMline
KW - Synchrotron X-ray computed tomography
KW - in-situ
PY - 2023
AN - OPUS4-57801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - PMD Workshop: Use and benefits of the PMDco
N2 - This is an interactive workshop of the Plattform MaterialDigital (PMD) on Semantic Web technologies (SWT) where we delve into the world of ontology development and data structuring in the field of materials science and engineering (MSE). This workshop is designed to equip participants with essential skills in categorizing classes within ontologies, with a special emphasis on the PMD Core Ontology (PMDco). Discover the immense value of ontologies for MSE data reproducibility and reuse and harness the power of PMDco to foster your data management practices.
In this workshop, you will explore the intricacies of class categorization when developing ontologies in the MSE domain. Through interactive discussions and hands-on exercises, you will learn effective techniques for structuring and organizing ontologies to enhance data retrieval and analysis. You will gain valuable insights into best practices and considerations for class categorization, aiming at optimal data organization and management within your MSE projects.
One of the highlights of this workshop is the introduction to PMDco, a mid-level ontology in the field of MSE developed community-driven in the frame of the project PMD. Learn about PMDco, its underlying concepts, and its application in detail. Discover how PMDco provides a comprehensive framework for MSE data representation, enabling seamless integration and interoperability across different systems and platforms. In addition to exploring PMDco, this workshop will illustrate the benefits of data interoperability and SWT with respect to leveraging the full potential of MSE data.
T2 - NFDI MatWerk Conference 2023
CY - Siegburg, Germany
DA - 27.06.2023
KW - Workshop
KW - Ontology
KW - Plattform MaterialDigital
KW - PMDco
PY - 2023
AN - OPUS4-57802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Plattform MaterialDigital in DIN NA 062-01-42 AA
N2 - In dieser Präsentation werden die letzten Entwicklungen in der Plattform MaterialDigital (PMD) im DIN Normenausschuss 062-01-42 AA zur Zug- und Duktilitätsprüfung für Metalle vorgestellt. Dabei werden hauptsächlich die Entwicklungen und Neustrukturierung der PMD Core Ontology (PMDco) sowie die entsprechende Anpassung der Zugversuchsontologie (Tensile Test Ontology - TTO) inklusive des Datenmappings adressiert. Für das Datenmapping wurde ein speziell im Zusammenhang mit der PMD erstellter Zugversuchsdatensatz verwendet, welcher frei verfügbar in einem online Zenodo Repository veröffentlicht ist. Weiterhin wird die Weiterentwicklung der Norm in Verbindung mit ihrer folgenden Revision hinsichtlich der Integration von Aspekten zur Digitalisierung in der Materialwissenschaft und Werkstofftechnik sowie der Verwendung von semantischen Technologien, wie unter anderem ontologischen Repräsentationen von Materialien und Prozessen, diskutiert.
T2 - DIN NA 062-01-42 AA Meeting
CY - Berlin, Germany
DA - 14.06.2023
KW - Ontologie
KW - Semantic Web Technologies
KW - Normung
KW - DIN
KW - Plattform MaterialDigital
KW - Zugversuch
KW - Tensile Test
KW - Materialcharakterisierung
PY - 2023
AN - OPUS4-57803
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Unwanted X-ray emission in ultrashort pulse laser processing: From metallic to biological materials
N2 - Ultrashort laser pulses have become established in many industrial processes. Additionally, they are also an integral part of medical applications especially in ophthalmology and to some extent in dentistry. The availability of highly repetitive powerful laser sources and advanced laser beam control systems have favored these developments. However, the laser processing may be accompanied by the generation of unwanted X-rays. Small doses per laser pulse can accumulate to significant dose levels at high laser pulse repetition rates. Moreover, burst mode processing increases the X-ray dose rates compared to single pulse use and results in X-ray photon energies up to 40 keV for tungsten targets. For laser treatment of human teeth, clearly noticeable X-ray skin dose rates can be found. The paper summarizes the current state of the art in the field of undesired generation of X-ray radiation during ultrashort pulse laser processing in air.
T2 - Lasers in Manufacturing 2023 (LiM 2023)
CY - Munich, Germany
DA - 26.06.2023
KW - Ultrashort laser pulses
KW - Laser-induced X-ray emission
KW - Secondary hazard
PY - 2023
AN - OPUS4-57816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
A1 - Stawski, Tomasz
T1 - Crystallization study of transition metal phosphates: Characterization of a non-classical crystallization pathway
N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we investigate the crystallization of transition metal phosphate (TMP) compounds (NH4MPO4∙6H2O, M3(PO4)2∙8H2O with M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate) out of aqueous solutions, which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters has high potential as a P- and 3d metal recovery route. For this purpose, a detailed understanding of the crystallization process beginning from combination of solved ions and ending in a final crystalline product is required. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMPs could be controlled. Detailed investigations of the precipitation process in time using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases during the crystallization process. Over time, their complex amorphous framework changes significantly resulting simultaneously in an agglomeration and densification of the compound. After extended reaction times these colloidal nanophases condensed to a final crystal. However, the reaction kinetics of the formation of a final crystalline product and the lifetime of these intermediate phases vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications.
T2 - HZB Usermeeting 2023
CY - Berlin, Germany
DA - 22.06.2023
KW - Struvite
KW - Transition metal
KW - Phosphates
KW - Crystallization
KW - Amorphous phases
PY - 2023
AN - OPUS4-57775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gradt, Thomas
T1 - Reibungszahlen von Holz-Holz- und Holz-Stahl-Kontakten für Stoßdämpfer von CASTOR-Behältern
N2 - Holz wird vielfach in Stoßdämpfern von Transportbehältern für radioaktives Material eingsetzt. Dafür wird oftmals Fichtenholz verwendet. Die Reibung zwischen den dabei entstehenden Grenzflächen ist von entscheidender Bedeutung. Die Ergebnisse hierzu zeigen eine gleichmäßige, mit steigender Temperatur abfallende Reibung.
T2 - 63. Tribologie Fachtagung
CY - Göttingen, Germany
DA - 26.09.2022
KW - Reibung
KW - Hokz-Holz-Kontakte
KW - Holz-Stahl-Kontakte
KW - CASTOR-Behälter
KW - Stoßdämpfer
PY - 2022
AN - OPUS4-56018
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gradt, Thomas
A1 - Martin, Martin
A1 - Gleim, Tobias
T1 - Reibungszahlen von Holz-Holz- und Holz-Stahl-Kontakten für Stoßdämpfer von CASTOR-Behältern
N2 - Holz wird vielfach in Stoßdämpfern von Transportbehältern für radioaktives Material eingesetzt. Dafür wird oftmals Fichtenholz verwendet, das in mehreren Lagen und senkrecht zueinander liegender Faserrichtung zwischen einer inneren und einer äußeren Stahlhülle eingebaut wird. Die Reibung zwischen den dabei entstehenden Grenzflächen ist von entscheidender Bedeutung für die Stoß- und Energieabsorption, z. B. bei einem Aufprall des Behälters auf eine harte Unterlage. Um detaillierte Informationen für entsprechende numerische Simulationen zu bekommen, wurden in dieser Arbeit die Reibungszahlen von Holz-Holz- und Holz-Stahl-Paarungen bei für derartige Behälter relevanten Beanspruchungsbedingungen im Temperaturbereich zwischen -40°C und 90°C gemessen. Die Ergebnisse zeigen eine gleichmäßige, mit steigender Temperatur abfallende Reibung, wobei die Werte für Holz-Stahl-Paarungen zwischen 0,43 bei -40°C und 0,22 bei 90°C sowie für Holz-Holz-Kontakte zwischen 0,3 bei -40°C und 0,24 bei 90°C liegen.
T2 - 63. Tribologie-Fachtagung 2022
CY - Göttingen, Germany
DA - 26.09.2022
KW - Reibung
KW - Holz-Holz-Kontakte
KW - Holz-Stahl-Kontakte
KW - CASTOR-Behälter
KW - Stoßdämpfer
PY - 2022
SN - 978-3-9817451-7-7
SP - 23/1
EP - 23/4
AN - OPUS4-56021
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gradt, Thomas
T1 - Tribologisches Verhalten von a-C:H- und ta-C-Schichten in Methan- und Wasserstoffumgebung
N2 - Verschleißfeste Kohlenstoffschichten mit niedriger Reibung sind hervorragend für Anwendungen in der Erdgas- und Wasserstofftechnologie geeignet. Einige Varianten versagen jedoch in inerter Umgebung, was für die praktische Anwendung sehr nachteilig ist. Im Vortrag werden Beispiele aus Modellversuchen für verschiedene Varianten, auch für Flüssigmethan-Umgebung gezeigt.
T2 - Workshop: Nachhaltigkeit durch Tribologische Schichten
CY - Karlsruhe, Germany
DA - 17.05.2022
KW - Reibung
KW - Kohlenstoffschichten
KW - Methan
KW - Wasserstoff
KW - Tribologie
PY - 2022
AN - OPUS4-56014
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - On the quality of wear volume data of laboratory model tests
N2 - European tribological research organisations unify their capabilities for the European Tribology Centre (https://www.i-tribomat.eu/). At its core is a database, which data are made comparable and trusted via harmonised procedures for their generation. This contribution will focus on wear volume data.
T2 - 63. Tribologie-Fachtagung 2022
CY - Göttingen, Germany
DA - 27.09.2022
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Harmonisation
KW - Round robin tests
KW - Interlaboratory tests
KW - Wear volume
PY - 2022
AN - OPUS4-55880
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
A1 - Grundtner, R.
A1 - Newrkla, K.
A1 - Pagano, F.
A1 - Nyberg, E.
A1 - Heino, V.
A1 - Spaltmann, Dirk
T1 - On the quality of wear volume data of laboratory model tests
N2 - European tribological research organisations unify their capabilities for the European Tribology Centre (https://www.i-tribomat.eu/). At its core is a database, which data are made comparable and trusted via harmonised procedures for their generation. This contribution will focus on wear volume data.
T2 - 63. Tribologie-Fachtagung 2022
CY - Göttingen, Germany
DA - 26.09.2022
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Harmonisation
KW - Round robin tests
KW - Interlaboratory tests
KW - Wear volume
PY - 2022
SN - 978-3-9817451-7-7
SP - 192
EP - 194
PB - Gesellschaft für Tribologie e.V.
AN - OPUS4-55881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Griesche, Axel
A1 - Pfretzschner, Beate
A1 - Taparli, Ugur Alp
A1 - Kardjilov, N.
T1 - Time-Resolved Neutron Bragg-Edge Imaging: A Case Study by Observing Martensitic Phase Formation in Low Temperature Transformation (LTT) Steel during GTAW
N2 - Polychromatic and wavelength-selective neutron transmission radiography were applied during bead-on-plate welding on 5 mm thick sheets on the face side of martensitic low transformation temperature (LTT) steel plates using gas tungsten arc welding (GTAW). The in situ visualization of austenitization upon welding and subsequent α’-martensite formation during cooling could be achieved with a temporal resolution of 2 s for monochromatic imaging using a single neutron wavelength and of 0.5 s for polychromatic imaging using the full spectrum of the beam (white beam).
The spatial resolution achieved in the experiments was approximately 200 µm. The transmitted monochromatic neutron beam intensity at a wavelength of λ = 0.395 nm was significantly reduced during cooling below the martensitic start temperature M s since the emerging martensitic phase has a ~10% higher attenuation coefficient than the austenitic phase. Neutron imaging was significantly influenced by coherent neutron scattering caused by the thermal motion of the crystal lattice (Debye–Waller factor), resulting in a reduction in the neutron transmission by approx. 15% for monochromatic and by approx. 4% for polychromatic imaging.
KW - Neutron radiography
KW - Debye–Waller factor
KW - Austenite-to-martensite transformation
KW - Low transformation temperature (LTT) steel
KW - Bragg-edge imaging
KW - Gas tungsten arc welding (GTAW)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559077
DO - https://doi.org/10.3390/app112210886
VL - 11
IS - 22
PB - MDPI
AN - OPUS4-55907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 52, Heft 4
T3 - Amts- und Mitteilungsblatt der BAM - 4/2022
KW - Zulassungen
KW - Anerkennungen
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567677
SN - 0340-7551
VL - 52
IS - 4
SP - 405
EP - 460
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-56767
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brinkmann, M.
A1 - Wiehle, Philipp
T1 - Correlation between relative humidity and the strength and deformation characteristics of unstabilised earth masonry
N2 - The mechanical properties of unstabilised earthen building materials are distinctively influenced by changes in material moisture content. However, this moisture-dependency often remains unconsidered in the calculation of the load-bearing capacity of earth constructions. This paper aims to derive a convenient way to sufficiently consider the impact of different material moisture contents on the mechanical properties of unstabilised earth masonry. Therefore, the influence of relative humidity and temperature on the strength and deformation characteristics of unstabilised earth blocks, earth mortar and earth masonry is evaluated by conducting compression tests under various climate conditions. The results show that the compressive strength and the modulus of elasticity are linearly correlated with the relative humidity, whereas changes in temperature at constant relative humidity have no significant influence. To account the distinct moisture-dependency, a general applicable modification factor for unstabilised earthen materials is provided, which enables the adjustment of the compressive strength and the modulus of elasticity in dependency of arbitrary hygroscopic material moisture contents.
KW - Earth masonry
KW - Earth blocks
KW - Relative humidity
KW - Modulus of elasticity
KW - Moisture
KW - Compressive strength
KW - Stress–strain-relation
PY - 2023
DO - https://doi.org/10.1016/j.conbuildmat.2022.130048
SN - 0950-0618
VL - 366
IS - 22
SP - 1
EP - 11
PB - Elsevier BV
AN - OPUS4-56732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
A1 - Klinger, Christian
T1 - Schadensanalyse an Fahrradkomponenten - Fraktographie, Ursachen, Prävention
N2 - Komponenten von Fahrrädern werden im Betrieb vorwiegend schwingend beansprucht. Typische Werkstoffe sind Stahl, Aluminiumlegierungen, Messing, CFK und thermoplastische Kunststoffe. Da es sich, unabhängig von der Preiskategorie, um konstruktiven Leichtbau handelt, werden einige Bauteile betriebsfest mehr oder weniger weit oberhalb der Dauerfestigkeit ausgelegt. Die im normalen Betrieb auftretenden Schäden sind daher weit überwiegend Schwingbrüche. Andere Schadensmechanismen wie z.B. Korrosion spielen quantitativ eine untergeordnete Rolle. Schwingbrüche treten nach einer Periode unbemerkten Risswachstums oft ohne Vorwarnung und ohne makroskopische Verformung auf. Im Falle von sicherheitsrelevanten Komponenten wie Rahmen, Gabeln, Lenkern, Sattelstützen, Kurbelarmen oder Pedalen kann dies zu erheblichen Personenschäden führen, die den Wert des ursächlichen Bauteilschadens weit überschreiten.
Über einen langjährigen Zeitraum wurden gebrochene Komponenten aus dem Alltag und aus Gerichtsverfahren analysiert. Das Hauptaugenmerk lag hierbei auf der fraktographischen Analyse, teilweise wurden die zu Grunde liegenden Schadensursachen ermittelt. Einflussfaktoren sind beispielsweise konstruktive Kerben an ungünstigen Stellen, aber auch Werkstoffwahl und Fertigungsqualität spielen eine Rolle. In den meisten Fällen wurde jedoch die konstruktive Lebensdauer überschritten. Diese wird praktisch nie mitgeteilt, und eine wiederkehrende Prüfung sicherheitsrelevanter Bauteile findet nicht statt.
Im Sinne der Vermeidung von Schäden und Unfällen könnte darauf hingewirkt werden, für sicherheitsrelevante Komponenten Lebensdauern besser abzuschätzen und von der Laufleistung abhängige Sichtprüfungen zu empfehlen.
T2 - Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Fahrrad
KW - Fraktographie
KW - Lebensdauer
KW - Schadensanalyse
KW - Schadensprävention
KW - Öffentliche Sicherheit
PY - 2023
UR - https://dgm.de/fileadmin/DGM/Veranstaltungen/2022/Werkstoffpruefung/Tagungsband/WP2022-Tagungsband-online.pdf
SN - 978-3-88355-430-3
SP - 73
EP - 78
PB - DGM - Deutsche Gesellschaft für Materialkunde e.V
CY - Sankt Augustin
AN - OPUS4-56832
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
T1 - The SPONGE v.1.0.0: Modeling scattering of shapes by STL input, with absolute intensities and size distribution.
N2 - Simulates X-ray and Neutron scattering patterns from arbitrary shapes defined by STL files.
Features:
- Uses multithreading to compute a number of independent solutions, then uses the variance of the results to estimate an uncertainty on the output.
- Can be launched from the command line using an excel sheet to define settings, or from a jupyter notebook.
- Outputs scattering patterns in absolute units if the contrast is set.
- A Gaussian size distribution is available, where the relative scaling of objects for each repetion can be varied. Recommended to be used with limited width (max. 10%) to avoid artefacts.
- Writes results with settings to an archival HDF5 file.
Application examples:
This software has been used in several studies to date. For example, it has been used here to simulate a model scattering pattern for a cuboid shape, which was then fed forward into the McSAS3 analysis program for analyzing scattering patterns of polydisperse cuboids. A second use is here, where it was used for the modeling of flattened helices. In this paper, scattering pattern features could be matched with particular morphological changes in the structure. Lastly, this paper has an example where it was used to validate the analytical analysis model, and explore the realistic limits of application of the analytical model.
KW - Software
KW - Scattering pattern analysis
KW - Scattering pattern simulation
KW - X-ray
KW - Neutron
KW - Command-line interface
KW - Scattering pattern
KW - STL file input
KW - Python
KW - Arbitrary shapes
PY - 2023
DO - https://doi.org/10.6084/m9.figshare.21857130.v1
PB - Digital Science
CY - Cambridge, MA, USA
AN - OPUS4-56815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, Rudolf
T1 - Advanced materials broadening the scope of antibody-based analytical methods
N2 - Immunoanalytical Techniques, i.e., antibody-based analytical methods, have been used for decades in clinical diagnostics. What makes them attractive for other fields of application is their short time-to-result and high sensitivity. Microplate-based assays such as ELISA have been adopted early in environmental and food analysis. Yet, to make immunoassays even faster, more sensitive, robust, and, most desirable, portable, advanced materials, sometimes developed for other purposes, can be profitably used to achieve these goals. Materials can be novel labels, e.g., chemical or particle labels, such as fluorophores or nanoparticles. Carrier particles, such as magnetic or polymer beads, make it possible to adopt the assays to meso- or microfluidic set-ups and encoding them opens the path to multiplex analysis. Specialty electrodes can enable for higher sensitivity in electrochemical detection. All this broadens the scope of application and lowers effort and cost for analysis at the point-of-need.
T2 - ChemForum - Kolloquium des Instituts für Strukturchemie
CY - Lisbon, Portugal
DA - 07.09.2022
KW - Immunoassay
KW - Biosensor
KW - Antibody
PY - 2022
AN - OPUS4-56782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, Rudolf
T1 - Field Analysis by Antibody-based Analytical Methods: The Importance of Advanced Materials
N2 - Analytical methods based on the selectivity of antibodies, often called immunoassays, are a back-bone of clinical laboratory diagnostics. To bring them to the field, i.e., to make immunoanalytical methods portable, hopefully even faster, more sensitive, and robust, advanced materials are re-quired. Materials can be novel labels, e.g., chemical or particle labels, such as fluorophores or na-noparticles. Carrier particles, such as magnetic or polymer beads, make it possible to adopt the as-says to meso- or microfluidic set-ups and encoding them opens the path to multiplex analysis. Spe-cialty electrodes can enable for higher sensitivity in electrochemical detection. Without research into better materials, efforts to bring analysis to the point-of-need will not bear fruit.
T2 - Kolloquium des Aveiro Institut of Materials (CICECO) der Universität Aveiro
CY - Aveiro, Portugal
DA - 20.09.2022
KW - Immunoassay
KW - Biosensor
KW - Antibody
PY - 2022
AN - OPUS4-56785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Costard, René
T1 - “Kalte Pyrotechnik” – heißes Thema oder heiße Luft?
N2 - Das Poster zeigt Ergebnisse von Messungen der Verbrennungstemperaturen und Aerosolemissionen von "kalter Pyrotechnik" und einem Seenotrettungsmittel im Vergleich.
T2 - 44. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 14.04.2023
KW - Pyrotechnik
KW - Missbräuchliche Verwendung in Stadien
KW - Aerosole
PY - 2023
AN - OPUS4-57311
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dengel, Jörg
T1 - Untersuchung des Alterungsverhaltens von pyrotechnischen Seenotrettungsmitteln
N2 - Das Poster zeigt Ergnisse der Untersuchung der Alterungsprozesse von pyrotechnischen Seenotrettungsmitteln (kleine schwimmfähige Rauchsignale und Seenotfackeln). Dabei erfolgte die Bewertung der thermischen und chemischen Stabilität sowie der Funktionssicherheit. Die beschleunigte Alterung (EN 16263:2015) und andere Methoden wurden mit natürlich gealterten Gegenständen verglichen
T2 - 44. Informationstagung Sprengtechnik
CY - Siegen, Germany
DA - 14.04.2023
KW - Alterung von Pyrotechnik
KW - Seenotrettungsmittel
PY - 2023
AN - OPUS4-57312
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 1. Where is the Bragg angle?
N2 - The derivation of a crystal structure and its phase-specific parameters from a single wide-angle backscattered Kikuchi diffraction pattern requires reliable extraction of the Bragg angles. By means of the first derivative of the lattice profile, an attempt is made to determine fully automatically and reproducibly the band widths in simulated Kikuchi patterns. Even under such ideal conditions (projection centre, wavelength and lattice plane traces are perfectly known), this leads to a lattice parameter distribution whose mean shows a linear offset that correlates with the mean atomic number Z of the pattern-forming phase. The consideration of as many Kikuchi bands as possible reduces the errors that typically occur if only a single band is analysed. On the other hand, the width of the resulting distribution is such that higher image resolution of diffraction patterns, employing longer wavelengths to produce wider bands or the use of higher interference orders is less advantageous than commonly assumed.
KW - Bragg angles
KW - Kikuchi bands
KW - Kikuchi patterns
KW - First derivative
KW - Lattice parameters
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573141
DO - https://doi.org/10.1107/S1600576723000134
SN - 0021-8898
VL - 56
IS - Pt. 2
SP - 349
EP - 360
AN - OPUS4-57314
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 2. Offset corrections
N2 - A band width determination using the first derivative of the band profile systematically underestimates the true Bragg angle. Corrections are proposed to compensate for the resulting offset Δa/a of the mean lattice parameters derived from as many Kikuchi band widths as possible. For dynamically simulated Kikuchi patterns, Δa/a can reach up to 8% for phases with a high mean atomic number Z, whereas for much more common low-Z materials the offset decreases linearly. A predicted offset Δa/a = f(Z) is therefore proposed, which also includes the unit-cell volume and thus takes into account the packing density of the scatterers in the material. Since Z is not always available for unknown phases, its substitution by Zmax, i.e. the atomic number of the heaviest element in the compound, is still acceptable for an approximate correction. For simulated Kikuchi patterns the offset-corrected lattice parameter deviation is Δa/a < 1.5%. The lattice parameter ratios, and the angles α, β and γ between the basis vectors, are not affected at all.1.5%. The lattice parameter ratios, and the angles � , � and � between the basis vectors, are not affected at all.
KW - Mean atomic number
KW - Kikuchi patterns
KW - Lattice parameters
KW - Automated Bragg angle determination
KW - Lattice parameter determination
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573153
DO - https://doi.org/10.1107/s1600576723000146
SN - 0021-8898
VL - 56
IS - Pt. 2
SP - 361
EP - 366
AN - OPUS4-57315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 3. Pseudosymmetry
N2 - A pseudosymmetric description of the crystal lattice derived from a single wideangle Kikuchi pattern can have several causes. The small size (<15%) of the sector covered by an electron backscatter diffraction pattern, the limited precision of the projection centre position and the Kikuchi band definition are crucial. Inherent pseudosymmetries of the crystal lattice and/or structure also pose a challenge in the analysis of Kikuchi patterns. To eliminate experimental errors as much as possible, simulated Kikuchi patterns of 350 phases have been analysed using the software CALM [Nolze et al. (2021). J. Appl. Cryst. 54, 1012–1022] in order to estimate the frequency of and reasons for pseudosymmetric crystal lattice descriptions. Misinterpretations occur in particular when the atomic scattering factors of non-equivalent positions are too similar and reciprocal-lattice points are systematically missing. As an example, a pseudosymmetry prediction depending on the elements involved is discussed for binary AB compounds with B1 and B2 structure types. However, since this is impossible for more complicated phases, this approach cannot be directly applied to compounds of arbitrary composition and structure.
KW - Bravais lattices
KW - Pseudosymmetry
KW - Lattice point density
KW - Ordered/disordered structures
KW - Lattice distortion
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573169
DO - https://doi.org/10.1107/s1600576723000845
SN - 0021-8898
VL - 56
IS - Pt. 2
SP - 367
EP - 380
AN - OPUS4-57316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
T1 - Accessing radiation damage to biomolecules on the nanoscale by particle-scattering simulations
N2 - Radiation damage to DNA plays a central role in radiation therapy to cure cancer. The physico-chemical and biological processes involved encompass huge time and spatial scales. To obtain a comprehensive understanding on the nano and the macro scale is a very challenging tasks for experimental techniques alone. Therefore particle-scattering simulations are often applied to complement measurements and aide their interpretation, to help in the planning of experiments, to predict their outcome and to test damage models. In the last years, powerful multipurpose particle-scattering framework based on the Monte-Carlo simulation (MCS) method, such as Geant4 and Geant4-DNA, were extended by user friendly interfaces such as TOPAS and TOPAS-nBio. This shifts their applicability from the realm of dedicated specialists to a broader range of scientists. In the present review we aim to give an overview over MCS based approaches to understand radiation interaction on a broad scale, ranging from cancerous tissue, cells and their organelles including the nucleus, mitochondria and membranes, over radiosensitizer such as metallic nanoparticles, and water with additional radical scavenger, down to isolated biomolecules in the form of DNA, RNA, proteins and DNA-protein complexes. Hereby the degradation of biomolecules by direct damage from inelastic scattering processes during the physical stage, and the indirect damage caused by radicals during the chemical stage as well as some parts of the early biological response is covered. Due to their high abundance the action of hydroxyl radicals (•OH) and secondary low energy electrons (LEE) as well as prehydrated electrons are covered in additional detail. Applications in the prediction of DNA damage, DNA repair processes, cell survival and apoptosis, influence of radiosensitizer on the dose distribution within cells and their organelles, the study of linear energy transfer (LET), the relative biological effectiveness (RBE), ion beam cancer therapy, microbeam radiation therapy (MRT), the FLASH effect, and the radiation induced bystander effect are reviewed.
KW - DNA
KW - Protein
KW - G5P
KW - OH
KW - Au
KW - AuNP
KW - Radiation
KW - SSB
KW - DSB
KW - Beta decay
KW - Brachytherapy
KW - Cancer treatment
KW - Clustered nanoparticles
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - Livermore model
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - OH radical
KW - Particle scattering
KW - Penelope model
KW - Proteins
KW - Radiation damage
KW - Radiation therapy
KW - Radiationtherapy
KW - Radioactive decay
KW - Radiolysis
KW - Radiotherapy
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
KW - Base damage
KW - Base loss
KW - DNA radiation damage
KW - Direct damage
KW - Dissociative electron attachment (DEA)
KW - Dissociative electron transfer (DET)
KW - Double-strand break (DSB)
KW - ESCA
KW - Hydrated DNA
KW - Hydrated electron
KW - Hydration shell
KW - Hydroxyl radical
KW - Indirect damage
KW - Ionization
KW - Ionisation
KW - NAP-XPS
KW - Near ambient pressure xray photo electron spectroscopy
KW - Net-ionization reaction
KW - Prehydrated electron
KW - Presolvated electron
KW - Quasi-direct damage
KW - ROS
KW - Radical
KW - Reactive oxygen species
KW - Single-strand break (SSB)
KW - XPS
KW - Xray
KW - Xray photo electron spectrocopy
KW - Cosolute
KW - Ectoin
KW - Ectoine
KW - GVP
KW - Gene five protein
KW - Hydroxyectoine
KW - Ionizing radiation damage
KW - OH radical scavenger
KW - Monte-Carlo simulations
KW - Nanodosimetry
KW - Osmolyte
KW - Particle scattering simulations
KW - Protein unfolding
KW - Radical Scavenge
KW - Radical scavenger
KW - Single-stranded DNA-binding proteins
KW - SAXS
KW - Bio-SAXS
KW - X-ray scattering
KW - ssDNA
KW - dsDNA
KW - FLASH effect
KW - Bystander effect
KW - Ion beam therapy
KW - Bragg peak
KW - LET
KW - MCNP
KW - Photons
KW - Electrons
KW - Carbon ions
KW - MRT
KW - RNA
KW - RBE
KW - base loss
KW - abasic side
KW - DMSO
KW - Cells
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573240
DO - https://doi.org/10.1088/2399-6528/accb3f
SN - 2399-6528
VL - 7
IS - 4
SP - 042001
PB - Institute of Physics (IOP) Publishing
CY - London
AN - OPUS4-57324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönauer-Kamin, D.
T1 - Powder Aerosol deposited (PAD) calcium cobaltite as textured p type thermoelectric material
N2 - Oxide thermoelectric semiconducting materials like p-type calcium cobaltite Ca3Co4O9 are investigated as oxidation- and temperature-resistant thermoelectric materials for thermoelectric generators (TEGs). To realize TEGs in planar film technology, the powder aerosol deposition (PAD) method is emerging recently. PAD is a method to obtain dense ceramic films directly from the synthesized starting powders without a subsequent high temperature step.
In the present work, Ca3Co4O9 (CCO) powders are processed by PAD to ceramic films at room temperature. The thermoelectric properties of the films (film thickness 10 – 20 µm) are characterized from room temperature to 900°C. Additionally, the layer morphology and texture of the films will be investigated.
As result, the Seebeck coefficient of the CCO-PAD film is comparable to pressed and sintered CCO-bulk materials during the 1st heating cycle to 900°C. The morphology of the films after the thermal treatment shows strong aligned crystallites resulting in a strong texture of the films. The electrical conductivity increases strongly during the 1st heating cycle to 900°C and stays almost constant afterwards. Compared to CCO-bulks, the films provide higher electrical conductivity which could be explained by the oriented crystal growth in-plane direction of the film.
The relationship between thermoelectric properties and layer morphology as a function of thermal annealing parameters will be further investigated.
T2 - KERAMIK 2023 / 98. DKG-Jahrestagung
CY - Jena, Germany
DA - 27.03.2023
KW - Layer depostion
KW - Texture
KW - Heat treatment
PY - 2023
AN - OPUS4-57285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Godard, A.
A1 - Kalot, G.
A1 - Privat, M.
A1 - Bendellaa, M.
A1 - Busser, B.
A1 - Wegner, Karl David
A1 - Denat, F.
A1 - Le Guevel, X.
A1 - Coll, J.-L.
A1 - Paul, C.
A1 - Bodio, E.
A1 - Goze, C.
A1 - Sancey, L.
T1 - NIR-II Aza-BODIPY Dyes Bioconjugated to Monoclonal Antibody Trastuzumab for Selective Imaging of HER2-Positive Ovarian Cancer
N2 - Using fluorescence-guided surgery (FGS) to cytoreductive surgery helps achieving complete resection of microscopic ovarian tumors. The use of visible and NIR-I fluorophores has led to beneficial results in clinical trials; however, involving NIR-II dyes seems to outperform those benefits due to the deeper tissue imaging and higher signal/noise ratio attained within the NIR-II optical window. In this context, we developed NIR-II emitting dyes targeting human epidermal growth factor receptor 2 (HER2)-positive ovarian tumors by coupling water-soluble NIR-II aza-BODIPY dyes to the FDA-approved anti-HER2 antibody, namely, trastuzumab. These bioconjugated NIR-II-emitting dyes displayed a prolonged stability in serum and a maintained affinity toward HER2 in vitro. We obtained selective targeting of HER2 positive tumors (SKOV-3) in vivo, with a favorable tumor accumulation. We demonstrated the fluorescence properties and the specific HER2 binding of the bioconjugated dyes in vivo and thus their potential for NIR-II FGS in the cancer setting.
KW - NIR-II
KW - Fluorescent dye
KW - In vivo imaging
KW - Ovarian cancer
KW - Antibody conjuagtes
KW - Bioimaging
PY - 2023
DO - https://doi.org/10.1021/acs.jmedchem.3c00100
SN - 0022-2623
VL - 66
IS - 7
SP - 5185
EP - 5195
PB - ACS Publications
AN - OPUS4-57293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dümmel, Martin
T1 - Consumer fireworks in europe - challenges for the future
N2 - This presentation gives a brief overview on the current situation of fireworks safety and security on the EU market, outlines the current standardization request of the European Commission with new and more stringent requirements and gives a perspective to further challenges for fireworks in Europe.
T2 - 18th International Symposium on Fireworks
CY - Valetta, Malta
DA - 24.04.2023
KW - Fireworks
KW - Standardisation
KW - Pyrotechnics
PY - 2023
AN - OPUS4-57389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dümmel, Martin
T1 - Consumer fireworks in europe – challenges for the future
N2 - This paper gives a brief overview on the current situation of fireworks safety and security on the EU market, outlines the current standardization request of the European Commission with new and more stringent requirements and gives a perspective to further challenges for fireworks in Europe.
T2 - 18th International Symposium on Fireworks
CY - Valetta, Malta
DA - 24.04.2023
KW - Pyrotechnic articles
KW - Fireworks
KW - Standardisation
PY - 2023
SN - 978-0-9867279-6-2
SP - 33
EP - 42
PB - International Symposium on Fireworks Society Ltd.
CY - Whitefish Bay, Wisconsin 53217-5968 USA
AN - OPUS4-57395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Strahlenexpositionen bei der Anwendung von Ultrakurzpulslasern in der Medizin
N2 - Die Erzeugung unerwünschter Röntgenstrahlung bei der Ultrakurzpulslaser-Bearbeitung von Cornea und Zahnmaterial wurde untersucht. Laser-induzierte Dosisleistungen über dem natürlichen Hintergrund wurden gemessen. Mögliche Strahlenexpositionen in realen Anwendungen am Menschen wurden im Online-Vortrag diskutiert. Im Rahmen des vom BfS geförderten Projektes haben die Hochschule Mittweida und die BAM gemeinsam Untersuchungen durchgeführt.
T2 - Kolloquium des Bundesamtes für Strahlenschutz (BfS)
CY - Online meeting
DA - 18.04.2023
KW - Ultrakurzpulslaser
KW - Laser-induzierte Röntgenstrahlung
KW - Medizinische Anwendung
KW - Auge
KW - Zahn
PY - 2023
AN - OPUS4-57362
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D.
A1 - Kozadayeva, M.
A1 - Koptyug, A.
A1 - Mishurova, Tatiana
A1 - Meinel, Dietmar
A1 - Surmenev, R.
A1 - Surmeneva, M.
T1 - Geometrical features and mechanical properties of the sheet-based gyroid scaffolds with functionally graded porosity manufactured by electron beam melting
N2 - Functionally graded porous scaffolds (FGPS) constructed with pores of different size arranged as spatially continuous structure based on sheet-based gyroid with three different scaling factors of 0.05, 0.1 and 0.2 were produced by electron beam powder bed fusion. The pore dimensions of the obtained scaffolds satisfy the values required for optimal bone tissue ingrowth. Agglomerates of residual powder were found inside all structures, which required post-manufacturing treatment. Using X-ray Computed Tomography powder agglomerations were visualized and average wall thickness, wall-to-wall distances, micro- and macro-porosities were evaluated. The initial cleaning by powder recovery system (PRS) was insufficient for complete powder removal. Additional treatment by dry ultrasonic vibration (USV) was applied and was found successful for gyroids with the scaling factors of 0.05 and 0.1. Mechanical properties of the samples, including quasi-elastic gradients and first maximum compressive strengths of the structures before and after USV were evaluated to prove that additional treatment does not produce structural damage. The estimated quasi-elastic gradients for gyroids with different scaling factors lie in a range between 2.5 and 2.9 GPa, while the first maximum compressive strength vary from 52.5 for to 59.8 MPa, compressive offset stress vary from 46.2 for to 53.2 MPa.
KW - Additive manufacturing
KW - Electron beam
KW - Powder bed fusion
KW - Triply periodic minimal surfaces
KW - Functionally graded porous scaffolds
KW - X-ray computed tomography
PY - 2023
DO - https://doi.org/10.1016/j.mtcomm.2023.106410
SN - 2352-4928
VL - 35
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-57682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obaton, A.-F.
A1 - Fain, J.
A1 - Meinel, Dietmar
A1 - Tsamos, Athanasios
A1 - Léonard, F.
A1 - Lécuelle, B.
A1 - Djemaï, M.
T1 - In Vivo Bone Progression in and around Lattice Implants Additively Manufactured with a New Titanium Alloy
N2 - The osseointegration in/around additively manufactured (AM) lattice structures of a new titanium alloy, Ti–19Nb–14Zr, was evaluated. Different lattices with increasingly high sidewalls gradually closing them were manufactured and implanted in sheep. After removal, the bone–interface implant (BII) and bone–implant contact (BIC) were studied from 3D X-ray computed tomography images. Measured BII of less than 10 µm and BIC of 95% are evidence of excellent osseointegration.
Since AMnaturally leads to a high-roughness surface finish, the wettability of the implant is increased.
The new alloy possesses an increased affinity to the bone. The lattice provides crevices in which the biological tissue can jump in and cling. The combination of these factors is pushing ossification beyond its natural limits. Therefore, the quality and speed of the ossification and osseointegration in/around these Ti–19Nb–14Zr laterally closed lattice implants open the possibility of bone spline key of prostheses. This enables the stabilization of the implant into the bone while keeping the possibility of punctual hooks allowing the implant to be removed more easily if required. Thus, this new titanium alloy and such laterally closed lattice structures are appropriate candidates to be implemented in a new generation of implants.
KW - Osseointegration
KW - X-ray computed tomography
KW - Additive manufacturing
KW - Machine learning segmentation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577066
DO - https://doi.org/10.3390/app13127282
VL - 13
IS - 12
SP - 1
EP - 18
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-57706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krauss, S. W.
A1 - Eckardt, M.
A1 - Will, J.
A1 - Spiecker, E.
A1 - Siegel, R.
A1 - Dulle, M.
A1 - Schweins, R.
A1 - Pauw, Brian Richard
A1 - Senker, J.
A1 - Zobel, M.
T1 - H-D-isotope effect of heavy water affecting ligand-mediated nanoparticle formation in SANS and NMR experiments
N2 - An isotopic effect of normal (H2O) vs. heavy water (D2O) is well known to fundamentally affect structure and chemical properties of proteins, for instance. Here we correlate results from small angle X-ray and neutron scattering (SAXS, SANS) with high-resolution scanning transmission electron microscopy to track the evolution of CdS nanoparticle size and crystallinity from aqeuous solution in presence of the organic ligand ethylenediaminetetraacetate (EDTA) at room temperature in both H2O and D2O. We provide evidence via SANS experiments that exchanging H2O by D2O impacts nanoparticle formation by changing the equilibria and dynamics of EDTA clusters in solution as investigated by nuclear magnetic resonance. The colloidal stability of the CdS nanoparticles, covered by a layer of [Cd(EDTA)]2- complexes, is significantly reduced in D2O despite the strong stabilizing effect of EDTA in suspensions of normal water. Hence, conclusions about nanoparticle formation mechanisms from D2O solutions can bare limited transferability to reactions in normal water due to isotopic effects, which thus need to be discussed for contrast match experiments.
KW - General Materials Science
KW - Quantum dots
KW - CdS
KW - Deuterium
KW - X-ray scattering
KW - MOUSE
PY - 2023
DO - https://doi.org/10.1039/D3NR02419A
SN - 2040-3364
VL - 15
IS - 40
SP - 16413
EP - 16424
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Sokolowski‐Tinten, Klaus
T1 - Probing Laser‐Driven Structure Formation at Extreme Scales in Space and Time
N2 - Irradiation of solid surfaces with high intensity, ultrashort laser pulses triggers a variety of secondary processes that can lead to the formation of transient and permanent structures over a large range of length scales from mm down to the nano‐range. One of the most prominent examples are LIPSS – Laser‐Induced Periodic Surface Structures. While LIPSS have been a scientific evergreen for of almost 60 years, experimental methods that combine ultrafast temporal with the required nm spatial resolution have become available only recently with the advent of short pulse, short wavelength free electron lasers. Here, the current status and future perspectives in this field are discussed by exploiting the unique possibilities of these 4th‐generation light sources to address by time‐domain experimental techniques the fundamental LIPSS‐question, namely why and how laser irradiation can initiate the transition of a “chaotic” (rough) surface from an aperiodic into a periodic structure.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Free electron laser
KW - Pump-probe experiments
KW - Time-resolved scattering
KW - Capillary waves
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595048
DO - https://doi.org/10.1002/lpor.202300912
SN - 1863-8899
VL - 18
SP - 1
EP - 11
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-59504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Petrushin, N. V.
A1 - Epishin, A. I.
A1 - Svetlov, I. L.
A1 - Nolze, Gert
A1 - Elyutin, E. S.
A1 - Solov'ev, A. E.
T1 - Influence of the Sign of the γ/γ' Misfit on the Structure and Creep Strength of Single Crystals of Nickel-Based Superalloys
N2 - Using the method of directional solidification, single crystals of experimental nickel-based superalloys with negative, zero, and positive γ/γ' misfits are obtained. The γ' solvus, solidus, and liquidus temperatures of the alloys are determined, and the microstructures of the alloys after directional solidification, heat treatment, and creep tests are investigated. Creep tests are performed at temperatures of 800 and 1000°C. It is found that single crystals of the alloy with a negative γ/γ' misfit have the highest creep resistance and lifetime (the crystal lattice period of the γ' phase is smaller than that of the γ matrix).
KW - Nickel-based superalloys
KW - Single crystal
KW - Creep
KW - Creep strength
KW - Microstructure, γ/γ' misfit
PY - 2023
DO - https://doi.org/10.1134/s207511332301029x
SN - 2075-1133
VL - 14
IS - 1
SP - 13
EP - 22
AN - OPUS4-59505
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keshmiri, Hamid
A1 - Cikes, Domagoj
A1 - Samalova, Marketa
A1 - Schindler, Lukas
A1 - Appel, Lisa-Marie
A1 - Urbanek, Michal
A1 - Yudushkin, Ivan
A1 - Slade, Dea
A1 - Weninger, Wolfgang J.
A1 - Peaucelle, Alexis
A1 - Penninger, Josef
A1 - Elsayad, Kareem
T1 - Brillouin light scattering anisotropy microscopy for imaging the viscoelastic anisotropy in living cells
N2 - Maintaining and modulating mechanical anisotropy is essential for biological processes. However, how this is achieved at the microscopic scale in living soft matter is not always clear. Although Brillouin light scattering (BLS) spectroscopy can probe the mechanical properties of materials, spatiotemporal mapping of mechanical anisotropies in living matter with BLS microscopy has been complicated by the need for sequential measurements with tilted excitation and detection angles. Here we introduce Brillouin light scattering anisotropy microscopy (BLAM) for mapping high-frequency viscoelastic anisotropy inside living cells. BLAM employs a radial virtually imaged phased array that enables the collection of angle-resolved dispersion in a single shot, thus enabling us to probe phonon modes in living matter along different directions simultaneously. We demonstrate a precision of 10 MHz in the determination of the Brillouin frequency shift, at a spatial resolution of 2 µm. Following proof-of-principle experiments on muscle myofibres, we apply BLAM to the study of two fundamental biological processes. In plant cell walls, we observe a switch from anisotropic to isotropic wall properties that may lead to asymmetric growth. In mammalian cell nuclei, we uncover a spatiotemporally oscillating elastic anisotropy correlated to chromatin condensation. Our results highlight the role that high-frequency mechanics can play in the regulation of diverse fundamental processes in biological systems. We expect BLAM to find diverse applications in biomedical imaging and material characterization.
KW - Optical and magnetic materials
KW - Atomic and molecular physics and optics
KW - Electronic
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595125
DO - https://doi.org/10.1038/s41566-023-01368-w
SN - 1749-4885
SN - 1749-4893
VL - 18
IS - 3
SP - 276
EP - 285
PB - Nature Publ. Group
CY - London
AN - OPUS4-59512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Characterisation of thin layers of Polydopamine used as functional coatings in X-Ray optics
N2 - Polydopamine (PDA) is a biological / biomimetic polymer which has spiked considerable interest in recent years. Its monomer is an important neurotransmitter and it is one of the strongest glues produced by biological organisms. Polydopamine is a candidate for several applications, mainly in the field of biology and medicine, but also - recently - for layer coatings with optical, electrical, and mechanical function.
In this work, we investigate PDA layers intended as reflectivity enhancers for mirror surfaces in X-ray astronomical observatories. It has previously been shown, that such X-ray telescopes can be improved by a coating of PDA in the thickness range of several nm. Accurate thickness determination is required to monitor and optimise the coating process. We use spectroscopic ellipsometry to determine first the dielectric function of the polydopamine layers using model coatings of sufficient thickness. This data is then used to accurately determine the layer thickness of much thinner PDA layers. This study resulted in data on the thickness and dielectric function of PDA layers that could lead to a better understanding of the correlation of layer thickness and layer properties depending on the process parameters.
T2 - Deutsche Physikalische Gesellschaft - Frühjahrstagung
CY - Berlin, Germany
DA - 17.03.2024
KW - Ellipsometry
KW - Polydopamine
KW - Thin Polymer Layers
KW - X-Ray Reflectometry
KW - Biopolymers
PY - 2024
AN - OPUS4-59760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Singh, Amit Kumar
A1 - Mishra, Biswajit
A1 - Sinha, Om Prakash
T1 - Reduction Kinetics of Fluxed Iron Ore Pellets Made of Coarse Iron Ore Particles
N2 - The present work demonstrates a sustainable approach of using relatively coarser iron ore particles for ironmaking. The motivation is to reduce the energy consumption in the milling of the iron ore by utilizing coarser iron ore particles (+0.05 mm) and to select a suitable binder for improving pellet properties. Iron ore fines in the range of 0.05–0.25 mm was selected and classified into three size ranges. Fluxed iron ore pellets were prepared using lime as a binder for the basicity of 0, 1, and 2. Reduction of these pellets with a packed bed of coal fines was performed in the temperature range of 900–1200 °C for a duration of 30–120 min. The direct reduction kinetics of the iron ore pellets were studied by employing diffusion and chemical reaction control models to the experimental data. The results show that pellets made with coarser iron ore particles have improved reduction behavior and kinetics. The reduction reaction is found to be a mixed control. The activation energy for the reduction reaction varies from 44.3 to 74.76 kJ mol−1 as iron ore particle size decreases from 0.25 to 0.05 mm and basicity increases from 0 to 2.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Process Metallurgy
KW - Iron making
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598326
DO - https://doi.org/10.1002/srin.202300669
SN - 1611-3683
IS - 2300669
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-59832
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schilling, Markus
T1 - Full-Notch Creep Test Ontology (ontoFNCT)
N2 - This is the stable version of the full-notch creep test ontology (OntoFNCT) that ontologically represents the full-notch creep test. OntoFNCT has been developed in accordance with the corresponding test standard ISO 16770:2019-09 Plastics - Determination of environmental stress cracking (ESC) of polyethylene - Full-notch creep test (FNCT).
The OntoFNCT provides conceptualizations that are supposed to be valid for the description of full-notch creep tests and associated data in accordance with the corresponding test standard. By using OntoFNCT for storing full-notch creep test data, all data will be well structured and based on a common vocabulary agreed on by an expert group (generation of FAIR data) which is meant to lead to enhanced data interoperability. This comprises several data categories such as primary data, secondary data and metadata. Data will be human and machine readable. The usage of OntoFNCT facilitates data retrieval and downstream usage. Due to a close connection to the mid-level PMD core ontology (PMDco), the interoperability of full-notch creep test data is enhanced and querying in combination with other aspects and data within the broad field of materials science and engineering (MSE) is facilitated.
The class structure of OntoFNCT forms a comprehensible and semantic layer for unified storage of data generated in a full-notch creep test including the possibility to record data from analysis and re-evaluation. Furthermore, extensive metadata allows to assess data quality and reliability. Following the open world assumption, object properties are deliberately low restrictive and sparse.
KW - Ontology
KW - Full-Notch Creep Test
KW - FNCT
KW - Knowledge Representation
KW - Semantic Web Technologies
KW - Data Structures
KW - Data Management
PY - 2024
UR - https://github.com/MarkusSchilling/ontoFNCT/blob/4abce82852190a5e444d302da077aa7404f433f0/ontoFNCT.ttl
UR - https://raw.githubusercontent.com/MarkusSchilling/ontoFNCT/main/ontoFNCT.ttl
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-59815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Swaminathan, Srinivasan
A1 - Sun, K.
A1 - Was, G. S.
T1 - Decoupling the roles of grain boundary oxidation and stress in IASCC of neutron-irradiated 304L stainless steel
N2 - Irradiation assisted stress corrosion cracking (IASCC) is known to be a combination of applied stress, and a corrosive environment in irradiated materials, but an appropriate understanding of how each of these components affects cracking is not yet clear. In this work, we isolate the role of grain boundary (GB) oxidation in IASCC. For this purpose, solution-annealed 304L stainless steel irradiated in reactor to 5.4 or 69 dpa was studied using a miniaturized four-point bend technique. Two modes of bend tests were conducted; straining in simulated pressurized water reactor primary water (PW) at 320 ◦C in an incremental manner, and pre-oxidation in PW at 320 ◦C without application of stress followed by dynamic straining in purified Ar at the same temperature until crack initiation. Exposure of the 5.4 dpa sample for 210 h in high temperature water initiated cracks in Ar at 60% of the yield stress (0.6YS), whereas the companion sample of the same dose exposed for 1010 h cracked in Ar at 0.5YS. The long-term exposure in water led to GB oxidation that ultimately lowered the crack initiation stress. Dynamic straining in water resulted in larger crack lengths and greater crack depths indicating stress accelerated oxidation and cracking. Dislocation pile-ups at dislocation channel-grain boundary sites provide an amplification of the applied stress to a level consistent with the fracture stress of the grain boundary oxide, providing an explanation for IASCC that occurs at applied stresses well below the irradiated yield stress of the alloy. There was no evidence of cracking upon straining of an unoxidized 69 dpa sample in Ar to well above yield, confirming that the irradiated state is not inherently susceptible to intergranular (IG) cracking and that oxidized GBs are responsible for initiation of IG cracking.
KW - Stress corrosion cracking
KW - Grain boundary oxidation
KW - Stainless steel
KW - Crack initiation
KW - IASCC
PY - 2023
DO - https://doi.org/10.1016/j.jnucmat.2023.154604
SN - 0022-3115
VL - 585
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-58233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Everything SAXS Part 1: Introduction, Sample Requirements and Measurement "Space"
N2 - This talk for the Swiss Society for Crystallography (SSCr) workshop on SAXS will introduce scattering from various angles, focusing in particular on:
- Information content of X-ray scattering experiments, three entry points…
- An introduction to Fourier Transforms
- Sample criteria, compatibility, and selection
- Key indicators of a measurement – where is the information?
- Key indicators of measurement quality
- Experiment planning, the basics
T2 - Topical workshop of the Swiss Society for Crystallography
CY - Zurich, Switzerland
DA - 08.09.2023
KW - X-ray scattering
KW - Data stewardship
KW - Measurement science
KW - MOUSE
KW - Holistic experiment approaches
PY - 2023
AN - OPUS4-58235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Everything SAXS Part 2: Data Processing, Workflow and Pitfalls
N2 - The second talk for the Swiss Society for Crystallography (SSCr) workshop on SAXS will highlight the data processing challenges, holistic experimental workflow developments, and the pitfalls. In particular, the following items will be addressed:
- The importance of data processing and estimating uncertainty
- A universal correction pipeline – away with the headaches, at least for this step!
- Experiment planning part 2, some tips and advice to improve your corrected data.
- Sample preparation, background selection, some tips and advice to improve your corrected data.
- Automate for your mental well-being; electronic logbooks, measurement catalogs and workflow management software
- Life on the edge: several pitfalls to avoid…
T2 - Topical workshop of the Swiss Society for Crystallography
CY - Zurich, Switzerland
DA - 08.09.2023
KW - X-ray scattering
KW - MOUSE
KW - Data processing
KW - Uncertainties
KW - Pitfalls
PY - 2023
AN - OPUS4-58236
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Additive Fertigungsverfahren und Defekte
N2 - Überblick über die derzeitig wichtigsten additiven Fertigungsverfahren für metallische Werkstoffe in der Industrie (PBF, DED, BJT) und Berücksichtigung der wesentlichen Prozessmerkmale und Nachbearbeitungsschritte. Vorstellung der wichtigsten Defektphänomene und Nennung von Ursachen und Abhilfemaßnahmen.
T2 - BAM Akademie: Qualitätssicherung in der additiven Fertigung
CY - Online meeting
DA - 14.09.023
KW - Additive Fertigung
KW - Defekte
KW - Überblick
PY - 2023
AN - OPUS4-58302
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Birkholz, H.
A1 - Bayerlein, Bernd
T1 - PMD Core Ontology: A Community Driven Mid-Level Ontology in the MSE Domain
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
In this presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Knowledge Representation
KW - Semantic Interioerability
KW - Mid-Level Ontology for MSE
KW - FAIR Data Management
PY - 2023
AN - OPUS4-58201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lemiasheuski, Anton
A1 - Bajer, Evgenia
A1 - Oder, Gabriele
A1 - Göbel, Artur
A1 - Hesse, Rene
A1 - Bettge, Dirk
T1 - Development of an Automated 3D Metallography System (RASI) and its Application in Microstructure Analysis
N2 - Many microstructural features exhibit non-trivial geometries, which can only be derived to a limited extent from two-dimensional images. E.g., graphite arrangements in lamellar gray cast iron have complex geometries, and the same is true for additively manufactured materials and three-dimensional conductive path structures. Some can be visualized using tomographic methods, but some cannot be due to weak contrast and/or lack of resolution when analyzing macroscopic objects. Classic metallography can help but must be expanded to the third dimension. The method of reconstructing three-dimensional structures from serial metallographic sections surely is not new. However, the effort required to manually assemble many individual sections into image stacks is very high and stands in the way of frequent application. For this reason, an automated, robot-supported 3D metallography system is being developed at BAM, which carries out the steps of repeated preparation and image acquisition on polished specimen.
Preparation includes grinding, polishing and optionally etching of the polished surface. Image acquisition comprises autofocused light microscopic imaging at several magnification levels. The image stacks obtained are then pre-processed, segmented, and converted into 3D models, which in the result appear like microtomographic models, but with high resolution at large volume. Contrasting by classical chemical etching reveals structures that cannot be resolved using tomographic methods. The integration of further imaging and measuring methods into this system is underway. Some examples will be discussed in the presentation.
T2 - Euromat 2023
CY - Frankfurt a. M., Germany
DA - 04.07.2023
KW - Metallography
KW - 3D Reconstruction
KW - Roboter
KW - Automation
KW - Microstructure
PY - 2023
AN - OPUS4-58202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Chewle, S.
A1 - Weber, M.
T1 - Revealing Kinetics of Paracetamol Crystallization Using Time Resolved Raman Spectroscopy, Orthogonal Time-Lapse Photography, and Non-Negative Matrix Factorization (OSANO)
N2 - Crystallization is a complex phenomenon with farreaching implications for the production and formulation of active pharmaceutical ingredients. Understanding this process is critical for achieving control over key physicochemical properties that can affect, for example, the bioavailability and stability of a drug. In this study, we were able to reveal intricate and diverse dynamics of the formation of metastable intermediates of paracetamol crystallization varying with the choice of solvent. We demonstrate the efficacy of our novel approach utilizing an objective function-based non-negative matrix factorization technique for the analysis of time-resolved Raman
spectroscopy data, in conjunction with time-lapse photography.
Furthermore, we emphasize the crucial importance of integrating Raman spectroscopy with supplementary experimental instrumentation for the mathematical analysis of the obtained spectra.
KW - Polymorphism
KW - Crystallization
KW - Measurement
KW - Algorithm
PY - 2023
DO - https://doi.org/10.1021/acs.cgd.3c00617
SN - 1528-7483
VL - 23
SP - 6737
EP - 6746
PB - ACS Publications
AN - OPUS4-58193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - PMDco - Platform MaterialDigital Core Ontology
N2 - The PMD Core Ontology (PMDco) is a comprehensive set of building blocks produced via consensus building. The ontological building blocks provide a framework representing knowledge about fundamental concepts used in Materials Science and Engineering (MSE) today. The PMDco is a mid-level ontology that establishes connections between narrower MSE application ontologies and domain neutral concepts used in already established broader (top-level) ontologies. The primary goal of the PMDco design is to enable interoperability between various other MSE-related ontologies and other common ontologies.
PMDco’s class structure is both comprehensive and extensible, rendering it an efficient tool to structure MSE knowledge. The PMDco serves as a semantic middle-layer unifying common MSE concepts via semantic mapping to other semantic representations using well-known key terms used in the MSE domain. The PMDco enables straight-forward documentation and tracking of science data generation and in consequence enables high-quality FAIR data that allows for precise reproducibility of scientific experiments.
The design of PMDco is based on the W3C Provenance Ontology (PROV-O), which provides a standard framework for capturing the production, derivation, and attribution of resources. Via this foundation, the PMDco enables the integration of data from various data origins and the representation of complex workflows.
In summary, the PMDco is a valuable advancement for researchers and practitioners in MSE domains. It provides a common MSE vocabulary to represent and share knowledge, allowing for efficient collaboration and promoting interoperability between diverse domains. Its design allows for the systematic integration of data and metadata, enabling seamless tracing of science data. Overall, the PMDco is a crucial step towards a unified and comprehensive understanding of the MSE domain in general.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Knowledge Representation
KW - Ontology
KW - Semantic Interoperability
KW - FAIR
KW - Automation
PY - 2023
AN - OPUS4-58197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bettge, Dirk
A1 - Schmies, Lennart
T1 - Die Fraktographische Online-Datenbank der AG Fraktographie – Entwicklungsstand und Planung
T1 - The WG Fractography Online Database – Stage of Development and Planning
N2 - Die AG Fraktographie im DVM/DGM-Gemeinschaftsgremium „Elektronenmikroskopie in der Materialforschung“ betreibt seit 2013 eine fraktographische online-Datenbank („FractoDB“), die für das interessierte Fachpublikum kostenfrei zur Verfügung steht. Die Analyse und Bewertung von Bruchflächen und der darauf befindlichen Bruchmerkmale ist ein wichtiger Teilaspekt der Schadensanalyse bei der Suche nach Schadensmechanismen und Schadensursachen. Risse und Brüche an realen Bauteilen können nur dann bewertet werden, wenn gut dokumentierte Vergleichsbrüche aus Laborversuchen zur Verfügung stehen, sei es an Proben oder an Vergleichs-Bauteilen. Daher trägt die AG Fraktographie Bildmaterial zusammen, führt systematisch Laborversuche und Ringversuche durch und analysiert Brüche aus Schadensfällen. Die gewonnenen Daten werden zu Datensätzen zusammengestellt und über die Datenbank zugänglich gemacht. Derzeit ist ein Bestand von über 400 Datensätzen mit insgesamt über 4.500 Bildern verfügbar, welcher durchsucht werden kann und in Anlehnung an die VDI 3822 organisiert ist. Weitere Aktivitäten der AG Fraktographie, die in der FractoDB abgebildet werden, sind u.a. die Entwicklung einer fraktographischen Symbolik und die Analyse von Bruchmerkmalen mittels Machine Learning. Über die aktuellen Ergebnisse und Planungen wird berichtet.
N2 - Since 2013, the AG Fraktographie (Working Group (WG) Fractography) in the DVM/DGM Joint Committee “Elektronenmikroskopie in der Materialforschung” (Electron Microscopy in Materials Research) maintains a fractographic online database (“FractoDB”) available to interested professionals. When it comes to identifying failure mechanisms and causes of damage, the analysis and evaluation of fracture surfaces and their characteristics constitute important aspects of the failure analysis. Cracks and fractures in real components can only be assessed if well-documented comparative fractures from laboratory tests are available – be it in samples or in comparison components. The WG Fractography therefore gathers image material, systematically carries out laboratory and round robin tests, and analyzes fractures from damage cases. From the thus obtained data, datasets are compiled and made available via the database. Currently, a browsable inventory of more than 400 datasets with a total of more than 4500 images is available. It is organized in line with guideline VDI 3822. Other activities of the WG Fractography represented in the FractoDB include, amongst others, the development of a fractographic set of symbols and the analysis of fracture characteristics using machine learning. This contributbution reports on latest results and plans.
KW - Fraktographie
KW - Datenbank
KW - Schadensanalyse
KW - Bruchflächen
KW - Machine Learning
PY - 2023
DO - https://doi.org/10.1515/pm-2023-0048
SN - 0032-678X
VL - 60
IS - 9
SP - 569
EP - 579
PB - De Gruyter
CY - Berlin
AN - OPUS4-58200
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bintz, Thilo
T1 - Investigation of Capillary Water Absorption of Clinker-Reduced Binders by NMR Relaxometry
N2 - To evaluate the durability of new alternative cement compositions, it is important to examine the internal transport of moisture through these materials. For this purpose, mortars were prepared from different types of cement and capillary suction experiments were carried out. The moisture transport was studied with an NMR tomograph and compared with weight easurements. With the tomograph, the total moisture input could be determined, as well as the moisture content within the samples non-destructively and spatially resolved. This allows precise observation of the moisture fronts. The tomograph was also used to determine the capillary transport
coefficient.
T2 - ISEMA 2023
CY - Queensland, Australia
DA - 25.09.2023
KW - NMR relaxometry
KW - Capillary suction
KW - Capillary transport coefficient
PY - 2023
AN - OPUS4-59216
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Suárez Ocano, Patricia
T1 - Thermodynamic and microstructural stabilities at high temperatures and their effects on mechanical properties in an AlMo0.5NbTa0.5TiZr refractory high entropy superalloy
N2 - Today’s industrial demands challenge the research and development sector to make advances in the design and properties of materials that can withstand harsh environments. The AlMo0.5NbTa0.5TiZr refractory high-entropy superalloy (RSA), with a remarkable morphological similarity to the γ/γ' microstructure of Ni-based superalloys and promising high-temperature compressive properties, has been considered as a candidate for structural applications. However, additional properties need to be investigated in order to assess the suitability of this alloy for high temperature applications. Therefore, this work investigates the thermodynamic and microstructural stabilities of the RSA at room temperature and between 900 and 1100 °C, and their influence on the mechanical properties. Although it is possible to improve the mechanical properties at 20 °C by tuning the cooling rate, long-term high temperature exposures lead to phase instabilities that negatively influence the creep behavior.
N2 - Die heutigen industriellen Anforderungen erfordern Fortschritte bei Werkstoffdesign und -entwicklung, insbesondere für raue Umgebungen. Die hochentropische Refraktärsuperlegierung (RSA) AlMo0.5NbTa0.5TiZr, die eine bemerkenswerte morphologische Ähnlichkeit mit der γ/γ'-Mikrostruktur von Ni-Basis-Superlegierungen und vielversprechende Hochtemperatur-Druckeigenschaften aufweist, wurde als Kandidat für strukturelle Anwendungen erwägt. Weitere Eigenschaften müssen untersucht werden, um die Eignung dieser Legierung für Hochtemperaturanwendungen zu beurteilen. In dieser Arbeit werden die thermodynamischen und mikrostrukturellen Stabilitäten von RSA bei Raumtemperatur und zwischen 900 und 1100°C sowie deren Einfluss auf die mechanischen Eigenschaften untersucht. Obwohl es möglich ist, die mechanischen Eigenschaften bei 20 °C durch Abstimmung der Abkühlrate zu verbessern, führen langfristige Hochtemperaturexpositionen zu Phaseninstabilitäten, die das Kriechverhalten negativ beeinflussen.
KW - Hochentropielegierung
KW - Gefüge (Werkstoffkunde)
KW - Mikrostruktur
KW - Kriechen
KW - Thermodynamische Stabilität
KW - High entropy alloys
KW - Microstructure
KW - Creep
KW - Thermodynamic stability
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:hbz:294-108415
DO - https://doi.org/10.13154/294-10841
SP - 1
EP - 170
CY - Bochum
AN - OPUS4-59929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hassenstein, Christian
A1 - Heckel, Thomas
A1 - Tomasson, Ingimar
A1 - Vöhringer, Daniel
A1 - Berendt, Torsten
A1 - Wassermann, Jonas
A1 - Prager, Jens
T1 - Automated Wall Thickness Evaluation for Turbine Blades Using Robot-Guided Ultrasonic Array Imaging
N2 - Nondestructive testing has become an essential part of the maintenance of modern gas turbine blades and vanes since it provides an increase in both safety against critical failure and efficiency of operation. Targeted repairs of the blade’s airfoil require localized wall thickness information. This information, however, is hard to obtain by nondestructive testing due to the complex shapes of surfaces, cavities, and material characteristics. To address this problem, we introduce an automated nondestructive testing system that scans the part using an immersed ultrasonic array probe guided by a robot arm. For imaging, we adopt a two-step, surface-adaptive Total Focusing Method (TFM) approach.
For each test position, the TFM allows us to identify the outer surface, followed by calculating an adaptive image of the interior of the part, where the inner surface’s position and shape are obtained. To handle the large volumes of data, the surface features are automatically extracted from the TFM images using specialized image processing algorithms. Subsequently, the collection of 2D extracted surface data is merged and smoothed in 3D space to form the outer and inner surfaces, facilitating wall thickness evaluation. With this approach, representative zones on two gas turbine vanes were tested, and the reconstructed wall thickness values were evaluated via comparison with reference data from an optical scan. For the test zones on two turbine vanes, average errors ranging from 0.05 mm to 0.1 mm were identified, with a standard deviation of 0.06–0.16 mm.
KW - Automation
KW - Imaging
KW - Sensors
KW - Testing methodologies
KW - Ultrasonics
PY - 2024
DO - https://doi.org/10.1115/1.4064998
SN - 2572-3901
VL - 7
SP - 021005-1
EP - 021005-12
PB - The American Society of Mechanical Engineers (ASME)
CY - New York, USA
AN - OPUS4-59851
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaytsev, D.
A1 - Funk, Alexander
T1 - On the crack evolutional in human dentin under uniaxial compression imaged by high resolution tomography
N2 - An observation of the fracture process in front of the crack tip inside a dentin sample by means of ex-situ X-ray computed tomography after uniaxial compression at different deformation values was carried out in this work. This ex-situ approach allowed the microstructure and fracturing process of human dentin to be observed during loading. No cracks are observed up to the middle part of the irreversible deformation in the samples at least visible at 0.4μm resolution. First cracks appeared before the mechanical stress reached the compression strength. The growth of the cracks is realized by connecting the main cracks with satellite cracks that lie ahead of the main crack tip and parallel its trajectory. When under the stress load the deformation in the sample exceeds the deformation at the compression strength of dentin, an appearance of micro-cracks in front of the main cracks is observed. The micro-cracks are inclined (~60°) to the trajectory of the main cracks. The further growth of the main cracks is not realized due to the junction with the micro-cracks; we assume that the micro-cracks dissipate the energy of the main crack and suppressed its growth. These micro-cracks serve as additional stress accommodations, therefore the samples do not break apart after the compression test, as it is usually observed under bending and tension tests.
KW - Dentin
KW - Crack evolution
KW - Compression strength
KW - Mechanical properties
KW - Microstructure
KW - Ex-situ X-ray computed tomography
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594810
DO - https://doi.org/10.18149/MPM.5152023_5
SN - 1605-8119
VL - 51
IS - 5
SP - 38
EP - 51
PB - Advanced Study Center
CY - St. Petersburg
AN - OPUS4-59481
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andreoli, A. F.
A1 - Fantin, Andrea
A1 - Kasatikov, S.
A1 - Bacurau, V. P.
A1 - Widom, M.
A1 - Gargarella, P.
A1 - Mazzer, E. M.
A1 - Woodcock, T. G.
A1 - Nielsch, K.
A1 - Coury, F. G.
T1 - The impact of chemical short-range order on the thermophysical properties of medium- and high-entropy alloys
N2 - The unusual behavior observed in the coefficient of thermal expansion and specific heat capacity of CrFeNi, CoCrNi, and CoCrFeNi medium/high-entropy alloys is commonly referred to as the K-state effect. It is shown to be independent of the Curie temperature, as demonstrated by temperature-dependent magnetic moment measurements. CoCrFeNi alloy is chosen for detailed characterization; potential reasons for the K-state effect such as texture, recrystallization, and second-phase precipitation are ruled out. An examination of the electronic structure indicates the formation of a pseudo-gap in the Density of States, which suggests a specific chemical interaction between Ni and Cr atoms upon alloying. Hybrid Monte Carlo/Molecular Dynamic (MC/MD) simulations indicate the presence of non-negligible chemical short-range order (CSRO). Local lattice distortions are shown to be negligible, although deviations around Cr and Ni elements from those expected in a fully disordered structure are experimentally observed by X-ray absorption spectroscopy. The determined bonding distances are in good agreement with MC/MD calculations. A mechanism is proposed to explain the anomalies and calorimetric experiments and their results are used to validate the mechanism.
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595869
DO - https://doi.org/10.1016/j.matdes.2024.112724
SN - 0264-1275
VL - 238
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-59586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - FAIR Data in Platform MaterialDigital (PMD) - Ontologies , Semantic Data Integration and Data Exchange
N2 - Following the new paradigm of materials development, design, and optimization, digitalization is the main goal in materials sciences and engineering (MSE) which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web technologies (SWT) are used since they allow for machine-actionable and human-readable knowledge representations needed for data management, retrieval, and (re)use.
The project ‘platform MaterialDigital’ (PMD, https://materialdigital.de) aims to bring together and support interested parties from both industrial and academic sectors in a sustainable manner in solving digitalization tasks and implementing digital solutions. Therefore, the establishment of a virtual material data space and the systematization of the handling of hierarchical, process-dependent material data are focused. Core points to be dealt with are the development of agreements on data structures and interfaces implemented in distinct software tools and to offer users specific support in their projects. Furthermore, the platform contributes to a standardized description of data processing methods in materials research. In this respect, selected MSE methods are semantically represented which are supposed to serve as best practice examples with respect to knowledge representation and the creation of knowledge graphs used for material data.
Accordingly, this presentation shows the efforts taken within the PMD project towards the digitalization in MSE such as the development of the mid-level PMD core ontology (PMDco, https://github.com/materialdigital/core-ontology). Furthermore, selected results of a PMD partner project use case addressing data and knowledge management from synthesis, production, and characterization of materials are shown.
T2 - 1st VMAP User Meeting 2024
CY - Sankt Augustin, Germany
DA - 14.02.2024
KW - Ontology
KW - Semantic Web Technologies
KW - Plattform MaterialDigital
KW - Data Interoperability
KW - Data Exchange
KW - Data Structures
PY - 2024
AN - OPUS4-59567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Pohl, Rainer
T1 - Wirbelstromprüfung am Schrein der Heiligen Drei Könige im Kölner Dom
N2 - Die Wirbelstromprüfung ist ein bewährtes Verfahren zur zerstörungsfreien Prüfung elektrisch leitfähiger Objekte im oberflächennahen Bereich. Nach einer Einführung in die Wirkungsweise, Möglichkeiten und Grenzen des Wirbelstromprüfverfahrens wird am Beispiel des Schreins der Heiligen Drei Könige gezeigt, wie sich mit dem Wirbelstromprüfverfahren unterschiedliche Metalllegierungen unter einer Vergoldung zerstörungsfrei identifizieren lassen.
Der Schrein der Heiligen Drei Könige wurde um das Jahr 1200 von Nikolaus von Verdun erschaffen, ca. 1750 von Johann Rohr und 1807 von Wilhelm Pollack restauriert. Die Restaurierungsarbeiten wurden jedoch nur unvollständig dokumentiert. Es ist bekannt, dass zu den unterschiedlichen Zeiten unterschiedliche Metalllegierungen als Grundmaterial unter der Vergoldung verwendet wurden. Mit Hilfe von Vergleichsproben aus einer Sammlung der Kölner Dombauverwaltung ließen sich die Akanthus-Prägungen des Schreins den verschiedenen Restaurierungen zuordnen.
T2 - 1. Fachseminar Historisches trifft Materialkunde
CY - Quedlinburg, Germany
DA - 20.02.2024
KW - Zerstörungsfreie Prüfung
KW - Wirbelstromprüfung
KW - Leitfähigkeitsmessung
PY - 2024
AN - OPUS4-59569
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - Applications of x-ray computed tomography in material science
N2 - The overview of the activity of Federal Institute for Material Research and Testing (BAM, Belin, Germany) in the field material characterization by X-ray imaging is presented. The principle of X-ray Computed Tomography (XCT) is explained. The multiple examples of application of quantitative analysis by XCT are reported, such as additive manufacturing, Li-ion battery, concrete research.
T2 - Lecture for PhD students at Politecnico di Torino
CY - Turin, Italy
DA - 14.03.2024
KW - X-ray computed tomography
KW - Additive manufacturing
PY - 2024
AN - OPUS4-59689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chazeau, E.
A1 - Fabre, C.
A1 - Privat, M.
A1 - Godard, A.
A1 - Racoeur, C.
A1 - Bodio, E.
A1 - Busser, B.
A1 - Wegner, Karl David
A1 - Sancey, L.
A1 - Paul, C.
A1 - Goze, C.
T1 - Comparison of the In Vitro and In Vivo Behavior of a Series of NIR-II-Emitting Aza-BODIPYs Containing Different Water-Solubilizing Groups and Their Trastuzumab Antibody Conjugates
N2 - The development of new fluorescent organic probes effective in the NIR-II region is currently a fast-growing field and represents a challenge in the domain of medical imaging. In this study, we have designed and synthesized an innovative series of aza-boron dipyrromethenes emitting in the NIR-II region. We have investigated the effect of different water-solubilizing groups not only on the photophysical properties of the compounds but also on their in vitro and in vivo performance after bioconjugation to the antibody trastuzumab. Remarkably, we discovered that the most lipophilic compound unexpectedly displayed the most favorable in vivo properties after bioconjugation. This underlines the profound influence that the fluorophore functionalization approach can have on the efficiency of the resulting imaging agent.
KW - NIR-II
KW - In vivo imaging
KW - Fluorescence
KW - Spectroscopy
KW - Antibody conjugates
PY - 2024
DO - https://doi.org/10.1021/acs.jmedchem.3c02139
SN - 1520-4804
VL - 67
IS - 5
SP - 3679
EP - 3691
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-59607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Gefährdung durch Röntgenemission bei der UKP-Laser-Materialbearbeitung
N2 - Der Vortrag gibt einen Überblick zu ultrakurzen Laserpulsen, der Ultrakurzpulslaser-Materialbearbeitung und der dabei ggf. auftretenden unerwünschten Röntgenstrahlung. Es wird die Laserbearbeitung von technischen und biologischen Materialien diskutiert. Schutzmöglichkeiten gegenüber der Röntgenstrahlung werden erörtert.
T2 - Sonthofer Strahlenschutztage 2024
CY - Sonthofen, Germany
DA - 11.03.2024
KW - Ultrakurzpulslaser
KW - Laser-induzierte Röntgenstrahlung
KW - Materialbearbeitung
KW - Technische Materialien
KW - Biologische Anwendungen
PY - 2024
AN - OPUS4-59667
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
T1 - Trinamic TMCL IOC for exposing Trinamics motor controllers to EPICS CA
N2 - Trinamic TMCL IOC is a Python package designed for controlling stepper motors connected to a Trinamic board using the TMCL language (all boards supported by PyTrinamic should now work, has been tested on the TMCM 6110 and the TMCM 6214). Since it is implementing the TMCL protocol, it should be easy to adapt to other Trinamic motor controller boards. This package assumes the motor controller is connected over a machine network via a network-to-serial converter, but the underlying PyTrinamic package allows for other connections too.
This allows the control of attached motors via the EPICS Channel-Access virtual communications bus. If EPICS is not desired, plain Pythonic control via motion_control should also be possible. An example for this will be provided in the example.ipynb Jupyter notebook.
This package leverages Caproto for EPICS IOCs and a modified PyTrinamic library for the motor board control, and interfaces between the two via an internal set of dataclasses. Configuration for the motors and boards are loaded from YAML files (see tests/testdata/example_config.yaml).
The modifications to PyTrinamic involved extending their library with a socket interface. This was a minor modification that should eventually find its way into the official package (a pull request has been submitted).
KW - Instrumentation
KW - Motor controller
KW - EPICS
KW - Channel access
KW - Instrument control
KW - Laboratory automation
PY - 2024
DO - https://doi.org/10.5281/zenodo.10792593
PB - Zenodo
CY - Geneva
AN - OPUS4-59624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Technologie und Werkzeuge für ultraschallunterstütztes Fräsen von Eisen- und Titan-Aluminid-Bauteilen
N2 - In der Abschlusspräsentation des ZIM-Kooperationsvorhabens "TeWuFeAl" werden die wichtigsten Ergebnisse zusammengefasst dargestellt. Ziel des Projektes war die Entwicklung einer Prozess- und Werkzeugtechnologie für das ultraschallunterstützte Fräsen von im Kokillenguss hergestellter Eisen- und Titan-Aluminid-Bauteilen. Auf Basis einer eigens entwickelten Werkzeugtechnologie und Prozessführung konnten die Belastungen auf das Werkzeug und die Oberfläche von Bauteilen aus dem schwer zerspanbaren Eisenaluminid bei der frästechnischen Bearbeitung signifikant verringert werden. Die Messung der Prozesskräfte und der thermischen Belastung der Werkzeugschneide ermöglicht die Ermittlung geeigneter Zerspanungsparameter für eine maximale Werkzeuglebensdauer. Die Anwendung des ultraschallunterstützten Fräsens (USAM) wirkt sich vorteilhaft auf den Zerspanprozess aus. Neben einer deutlichen verlängerung der Werkzeuglebensdauer, zeigen sich Vorteile in Bezug auf die topographischen, metallurgischen sowie mechanischen Eigenschaften der erzeugten Oberflächenintegrität. Die durch USAM erzeugte homogene Bauteiloberfläche weist eine reduzierte Defektdichte und verringerte Rauheitskennwerte auf. Besonders vielversprechend sind die Ergebnisse der Messungen der Eigenspannungen im Tiefenprofil der Oberfläche. Die Werkzeugoszillation bewirkt eine, vergleichbar zum Strahlprozess, Verdichtung der Oberfläche was in Druckeigenspannungen resultiert. Diese potenziell vorteilhaften Druckeigenspannungen können maßgeblich zur Risssicherheit hochbelasteter Komponenten und somit zum Leichtbau und Ressourceneffizienz beitragen.
T2 - Abschlusstreffen ZIM-Vorhaben "TeWuFeAl"
CY - Lampertheim, Germany
DA - 06.07.2023
KW - Eisenaluminid
KW - Ultraschallunterstütztes Fräsen
KW - Oberflächenintegrität
KW - Werkzeuglebensdauer
PY - 2023
AN - OPUS4-59389
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
T1 - Imaging spectroscopic ellipsometry for investigation of energy materials and materials for nano-electronics
N2 - Ellipsometry is a very powerful tool used for accurate material investigation in a wide wavelength range. It is a non-destructive and fast method. Imaging ellipsometry as a combination of optical microscopy and ellipsometry enables spatially resolved measurements when determining the layer thickness and dielectric properties of thin layers. It is known for its high polarisation sensitivity and high contrast for the surface structures. In this contribution we show the application of the imaging ellipsometry for detection of defects in energy materials and quality validation of possible reference materials for nano-electronics.
Defects in wide bandgap semiconductors, in homoepitaxial SiC and heteroepitaxial GaN layers on transparent SiC substrates, can be successfully detected and classified by means of imaging ellipsometry. Correlation of imaging ellipsometry results with results from complementary techniques such as white light interference microscopy as well as atomic force microscopy contribute to understanding of surface topography and defect formation mechanisms. We discuss the potential of different methods for analysing ellipsometric map data for monitoring the defect densities.
Electric properties of materials at the nanoscale can be investigated by means of scanning probe microscopy methods such as scanning microwave microscopy and conductive atomic force microscopy. However, development of new robust and easy-to-use calibration methods and calibration standards is essential to increase the traceability of these methods and allow their broad application in industry. We show how imaging spectroscopic ellipsometry can be used for development and monitoring of processing quality of patterned reference samples based on indium tin oxide (ITO) layer with different thickness and conductivity.
T2 - 12th Workshop on Spectroscopic Ellipsometry (WSE)
CY - Prague, Czech Republic
DA - 18.09.2023
KW - Ellipsometry
KW - Thin Films
KW - Transparent Conductive Oxides
KW - Energy materials
KW - White light interference microscopy
KW - Nanoelectronics
KW - Wide-bandgap semiconductors
PY - 2023
AN - OPUS4-59340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schilling, Markus
A1 - Bayerlein, Bernd
A1 - Birkholz, H.
A1 - Fliegener, S.
A1 - Grundmann, J.
A1 - Hanke, T.
A1 - von Hartrott, P.
A1 - Waitelonis, J.
T1 - PMD Core Ontology (PMDco)
N2 - The PMD Core Ontology (PMDco) is a comprehensive framework for representing knowledge that encompasses fundamental concepts from the domains of materials science and engineering (MSE). The PMDco has been designed as a mid-level ontology to establish a connection between specific MSE application ontologies and the domain neutral concepts found in established top-level ontologies. The primary goal of the PMDco is to promote interoperability between diverse domains. PMDco's class structure is both understandable and extensible, making it an efficient tool for organizing MSE knowledge. It serves as a semantic intermediate layer that unifies MSE knowledge representations, enabling data and metadata to be systematically integrated on key terms within the MSE domain. With PMDco, it is possible to seamlessly trace data generation. The design of PMDco is based on the W3C Provenance Ontology (PROV-O), which provides a standard framework for capturing the generation, derivation, and attribution of resources. By building on this foundation, PMDco facilitates the integration of data from various sources and the creation of complex workflows. In summary, PMDco is a valuable tool for researchers and practitioners in the MSE domains. It provides a common language for representing and sharing knowledge, allowing for efficient collaboration and promoting interoperability between diverse domains. Its design allows for the systematic integration of data and metadata, enabling seamless traceability of data generation. Overall, PMDco is a crucial step towards a unified and comprehensive understanding of the MSE domain. PMDco at GitHub: https://github.com/materialdigital/core-ontology
KW - Ontology
KW - Semantic Web technologies
KW - Digitalization
KW - Data Interoperability
KW - PMD Core Ontology
PY - 2023
UR - https://github.com/materialdigital/core-ontology/blob/f2bd420348b276583fad6fa0fb4225f17b893c78/pmd_core.ttl
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-59352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - Birkholz, Henk
A1 - Jung, Matthias
A1 - Waitelonis, Jörg
A1 - Mädler, Lutz
A1 - Sack, Harald
T1 - PMD Core Ontology: Achieving semantic interoperability in materials science
N2 - Knowledge representation in the Materials Science and Engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant (consistent) and variant (context-specific) knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this paper, an approach how to maintain a comprehensive MSE-centric terminology composing a mid-level ontology–the Platform MaterialDigital Core Ontology (PMDco)–via MSE community-based curation procedures is presented. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics. Additionally, it demonstrates how the PMDco lowers development and integration thresholds. Moreover, the research highlights how to fuel it with real-world data sources ranging from manually conducted experiments and simulations with continuously automated industrial applications.
KW - Ontology
KW - Materials science and engineering
KW - Knowledge representation
KW - Reproducibility
KW - Semantic interoperability
KW - Semantic data integration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592948
DO - https://doi.org/10.1016/j.matdes.2023.112603
SN - 0264-1275
VL - 237
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-59294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Barzegar, M.
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Mishurova, Tatiana
A1 - Pasadas, Dario J.
A1 - Ribeiro, Artur L.
A1 - Ramos, Helena G.
T1 - Adhesive Porosity Analysis of Composite Adhesive Joints Using Ultrasonic Guided Waves
N2 - Adhesively bonded composite joints can develop voids and porosity during fabrication, leading to stress concentration and a reduced load-carrying capacity. Hence, adhesive porosity analysis during the fabrication is crucial to ensure the required quality and reliability. Ultrasonic-guided wave (UGW)-based techniques without advanced signal processing often provide low-resolution imaging and can be ineffective for detecting small-size defects. This article proposes a damage imaging process for adhesive porosity analysis of bonded composite plates using UGWs measured by scanning laser Doppler vibrometer (LDV). To implement this approach, a piezoelectric transducer is mounted on the composite joint specimen to generate UGWs, which are measured over a densely sampled area. The signals obtained from the scan are processed using the proposed signal processing in different domains. Through the utilization of filter banks in frequency and wavenumber domains, along with the root-mean-square calculation of filtered signals, damage images of the adhesive region are obtained. It has been observed that different filters provide information related to different void sizes. Combining all the images reconstructed by filters, a final image is obtained which contains damages of various sizes. The images obtained by the proposed method are verified by radiography results and the porosity analysis is presented. The results indicate that the proposed methodology can detect the pores with the smallest detectable pore area of 2.41 mm^2, corresponding to a radius of 0.88 mm, with an overall tendency to overestimate the pore size by an average of 11%.
KW - Adhesives
KW - Damage imaging
KW - Nondestructive testing (NDT)
KW - Porosity analysis
KW - Signal processing
KW - Ultrasonic guided waves (UGWs)
PY - 2024
DO - https://doi.org/10.1109/TUFFC.2024.3371671
VL - 71
IS - 4
SP - 485
EP - 495
PB - Institute of Electrical and Electronics Engineers (IEEE)
AN - OPUS4-59970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Creating a Tribological Dataspace
N2 - Dataspaces are a concept to share and distribute data. Introducing this concept in a tribological context will help to provide a wider availability of the domain a deeper understanding of tribological phenomena.
T2 - Tribology Days 2023
CY - Hagen, Germany
DA - 15.11.2023
KW - Tribology
KW - i-TRIBOMAT
KW - Dataspace
KW - Digitalisation
KW - Harmonisation
KW - Database
PY - 2023
AN - OPUS4-58901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jablonka, Kevin Maik
A1 - Ai, Qianxiang
A1 - Al-Feghali, Alexander
A1 - Badhwar, Shruti
A1 - Bocarsly, Joshua D.
A1 - Bran, Andres M.
A1 - Bringuier, Stefan
A1 - Brinson, L. Catherine
A1 - Choudhary, Kamal
A1 - Circi, Defne
A1 - Cox, Sam
A1 - de Jong, Wibe A.
A1 - Evans, Matthew L.
A1 - Gastellu, Nicolas
A1 - Genzling, Jerome
A1 - Gil, María Victoria
A1 - Gupta, Ankur K.
A1 - Hong, Zhi
A1 - Imran, Alishba
A1 - Kruschwitz, Sabine
A1 - Labarre, Anne
A1 - Lála, Jakub
A1 - Liu, Tao
A1 - Ma, Steven
A1 - Majumdar, Sauradeep
A1 - Merz, Garrett W.
A1 - Moitessier, Nicolas
A1 - Moubarak, Elias
A1 - Mouriño, Beatriz
A1 - Pelkie, Brenden
A1 - Pieler, Michael
A1 - Ramos, Mayk Caldas
A1 - Ranković, Bojana
A1 - Rodriques, Samuel G.
A1 - Sanders, Jacob N.
A1 - Schwaller, Philippe
A1 - Schwarting, Marcus
A1 - Shi, Jiale
A1 - Smit, Berend
A1 - Smith, Ben E.
A1 - Van Herck, Joren
A1 - Völker, Christoph
A1 - Ward, Logan
A1 - Warren, Sean
A1 - Weiser, Benjamin
A1 - Zhang, Sylvester
A1 - Zhang, Xiaoqi
A1 - Zia, Ghezal Ahmad Jan
A1 - Scourtas, Aristana
A1 - Schmidt, K. J.
A1 - Foster, Ian
A1 - White, Andrew D.
A1 - Blaiszik, Ben
T1 - 14 examples of how LLMs can transform materials science and chemistry: a reflection on a large language model hackathon
N2 - Large-language models (LLMs) such as GPT-4 caught the interest of many scientists. Recent studies suggested that these models could be useful in chemistry and materials science. To explore these possibilities, we organized a hackathon. This article chronicles the projects built as part of this hackathon. Participants employed LLMs for various applications, including predicting properties of molecules and materials, designing novel interfaces for tools, extracting knowledge from unstructured data, and developing new educational applications. The diverse topics and the fact that working prototypes could be generated in less than two days highlight that LLMs will profoundly impact the future of our fields. The rich collection of ideas and projects also indicates that the applications of LLMs are not limited to materials science and chemistry but offer potential benefits to a wide range of scientific disciplines.
KW - Large Language model
KW - Hackathon
KW - Concrete
KW - Prediction
KW - Inverse Design
KW - Orchestration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589961
DO - https://doi.org/10.1039/d3dd00113j
VL - 2
IS - 5
SP - 1233
EP - 1250
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moreno Torres, Benjami
A1 - Völker, Christoph
A1 - Firdous, Rafia
T1 - Concreting a sustainable future: A dataset of alkali-activated concrete and its properties
N2 - This data article introduces a dataset comprising 1630 alkali-activated concrete (AAC) mixes, compiled from 106 literature sources. The dataset underwent extensive curation to address feature redundancy, transcription errors, and duplicate data, yielding refined data ready for further data-driven science in the field of AAC, where this effort constitutes a novelty. The carbon footprint associated with each material used in the AAC mixes, as well as the corresponding CO2 footprint of every mix, were approximated using two published articles. Serving as a foundation for future expansions and rigorous data applications, this dataset enables the characterization of AAC properties through machine learning algorithms or as a benchmark for performance comparison among different formulations. In summary, the dataset provides a resource for researchers focusing on AAC and related materials and offers insights into the environmental benefits of substituting traditional Portland concrete with AAC.
KW - Multidisciplinary
KW - Data Set
KW - Alkali Activated Concrete
KW - Data driven design
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589974
DO - https://doi.org/10.1016/j.dib.2023.109525
SN - 2352-3409
VL - 50
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-58997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
A1 - Zia, Ghezal Ahmad Jan
A1 - Rug, Tehseen
A1 - Firdous, Rafia
A1 - Böhmer, Felix
A1 - Stephan, Dietmar
A1 - Kruschwitz, Sabine
T1 - Presenting SLAMD – A Sequential Learning Based Software for the Inverse Design of Sustainable Cementitious Materials
N2 - In recent decades, the number of components in concrete has grown, particularly in formulations aimed at reducing carbon footprints. Innovations include diverse binders, supplementary cementitious materials, activators, concrete admixtures, and recycled aggregates. These developments target not only the enhancement of material properties but also the mitigation of the ecological and economic impacts of concrete — the most extensively used material by humankind. However, these advancements also introduce a greater variability in the composition of raw materials. The material’s behavior is significantly influenced by its nanoscale properties, which can pose challenges in accurate characterization. Consequently, there’s an increasing need for experimental tuning of formulations. This is accompanied by a more inconsistent composition of raw materials, which makes an experimental tuning of formulations more and more necessary. However, the increased complexity in composition presents a challenge in finding the ideal formulation through trial and error. Inverse design (ID) techniques offer a solution to this challenge by allowing for a comprehensive search of the entire design space to create new and improved concrete formulations. In this publication, we introduce the concept of ID and demonstrate how our open-source app “SLAMD” provides all necessary steps of the workflow to adapt it in the laboratory, lowering the application barriers. The intelligent screening process, guided by a predictive model, leads to a more efficient and effective data-driven material design process resulting in reduced carbon footprint and improved material quality while considering socio-economic factors in the materials design.
KW - Sustainable concrete
KW - Machine learning optimization
KW - Inverse design techniques
KW - Scientific software
KW - Data-driven material design
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589993
DO - https://doi.org/10.17756/nwj.2023-s2-032
VL - 9
SP - 180
EP - 187
AN - OPUS4-58999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmies, Lennart
A1 - Hemmleb, Matthias
A1 - Bettge, Dirk
T1 - Relevant input data for crack feature segmentation with deep learning on SEM imagery and topography data
N2 - Fractography plays a critical role in failure analysis of engineering components and has a considerable importance for safety investigations. Usually, the interpretation of fracture surfaces is done by experts with the help of literature and experimental data, that requires a lot of experience. The use of deep learning (DL) with neural networks in failure analysis becomes more and more relevant with the rapidly developing possibilities. Especially, the modern network architectures can assist fractographers in determining various fracture features on SEM images of the fracture surfaces. The basis for the best possible evaluation is the understanding of the influence of the input data used for training deep neural networks (DNN). Therefore, this study discusses the influence of the selection of the input data used for the prediction quality of these networks in order to take this into account for future data acquisition. Specimens of various metallic materials were subjected to fatigue cracking experiment under laboratory conditions. The fractured surfaces were then imaged using various modes or detectors (such as SE, BSE and topography) in SEM, and those captured images were used to create a training data set. The relevance of the individual data for the quality of the prediction is determined by a specific combination of the different detector data. For the training, the well-established architecture of a UNet-ResNet34 with a fixed set of hyperparameters is used. It has been found in this present study that the combination of all input data significantly increases the prediction accuracy, whereby even the combination of SE and BSE data provides considerable advantages over the exclusive use of SE images.
KW - Fractography
KW - Machine Learning
KW - Deep Learning
KW - KI
PY - 2023
DO - https://doi.org/10.1016/j.engfailanal.2023.107814
VL - 156
SP - 1
EP - 8
PB - Elsevier
AN - OPUS4-58918
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schwarz, Silke
T1 - Elektrostatische Empfindlichkeit von Explosivstoffen: Erfahrungen und Probleme mit dem X-Spark-10
N2 - Der Vortrag fasst erste messtechnische Erfahrungen, Ergebnisse und Probleme bei der Bestimmung der elektrostatischen Empfindlichkeit zusammen.
T2 - BAM-Workshop "Bestimmung der elektrostatischen Empfindlichkeit energetischer Stoffe"
CY - Berlin, Germany
DA - 20.11.2023
KW - Elektrostatische Empfindlichkeit
KW - Explosivstoffe
PY - 2023
AN - OPUS4-58934
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cook, Jake Thomas
T1 - Assessment of concrete bioreceptivity in algal biofilm green façade systems
N2 - Content: Why Algal Biofilm Green Façade Systems?, Factors Influencing Bioreceptivity, Influence of pH and Microorganism Symbiosis, Pulse-Amplitude-Modulation (PAM) Fluorometry
T2 - International Conference on Bio-Based Building Materials
CY - Vienna, Austria
DA - 21.06.2023
KW - Concrete
KW - Façade
KW - Bio-receptive
KW - Extracellular polymeric substances
KW - Fractional factorial
PY - 2023
UR - https://www.rilem.net/agenda/5th-international-conference-on-bio-based-building-materials-1501
AN - OPUS4-58962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weichert, Dorina
A1 - Kister, Alexander
A1 - Volbach, Peter
A1 - Houben, Sebastian
A1 - Trost, Marcus
A1 - Wrobel, Stefan
T1 - Explainable production planning under partial observability in high-precision manufacturing
N2 - Conceptually, high-precision manufacturing is a sequence of production and measurement steps, where both kinds of steps require to use non-deterministic models to represent production and measurement tolerances. This paper demonstrates how to effectively represent these manufacturing processes as Partially Observable Markov Decision Processes (POMDP) and derive an offline strategy with state-of-the-art Monte Carlo Tree Search (MCTS) approaches. In doing so, we face two challenges: a continuous observation space and explainability requirements from the side of the process engineers. As a result, we find that a tradeoff between the quantitative performance of the solution and its explainability is required. In a nutshell, the paper elucidates the entire process of explainable production planning: We design and validate a white-box simulation from expert knowledge, examine state-of-the-art POMDP solvers, and discuss our results from both the perspective of machine learning research and as an illustration for high-precision manufacturing practitioners.
KW - Explainability
KW - Manufacturing
KW - Reinforcement Learning
KW - Monte Carlo tree search
KW - Partially observable Markov decision process
PY - 2023
DO - https://doi.org/10.1016/j.jmsy.2023.08.009
SN - 0278-6125
VL - 70
SP - 514
EP - 524
PB - Elsevier Ltd.
CY - Southfield
AN - OPUS4-58963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cook, Jake Thomas
T1 - Assessment of concrete bioreceptivity in algal biofilm green façade systems
N2 - Algal biofilm façades are an alternative to traditional green façades which can help to improve biodiversity and air quality within cities. They present a low maintenance approach in which subaerial algae are grown directly on concrete substrates. The intrinsic bioreceptivity of the substrate is a critical factor in successful facade colonisation. Existing research has identified several environmental and material properties which influence concrete bioreceptivity, however a consensus has yet to be made on which properties are most influential and how the interaction between properties may promote algal biofilm growth under specific conditions.
T2 - International Conference on Bio-Based Building Materials
CY - Vienna, Austria
DA - 21.06.2023
KW - Concrete
KW - Façade
KW - Bio-receptive
KW - Extracellular polymeric substances
KW - Fractional factorial
PY - 2023
UR - https://www.rilem.net/agenda/5th-international-conference-on-bio-based-building-materials-1501
AN - OPUS4-58976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Electron-beam induced particle synthesis: Phenomenological study of the physical mechanisms
N2 - Several studies have shown that the electron beam (e-beam) can be used to create nanomaterials from microparticles in situ in a TEM. However, attempts to produce gold nanoparticles (NPs) on silicon oxide substrate remained to be accomplished. Here, we show that the production of gold NPs is possible by using the e-beam in a SEM, under a set of parameters. To understand the physical mechanisms leading to the gold NPs, the mechanisms of e-beam induced charging as well as e-beam induced heating of the MPs were discussed. Several hints point to heating as the driving mechanism.
T2 - IFW Dresden, Seminar
CY - Dresden, Germany
DA - 06.12.2023
KW - Electron-beam-induced modification
KW - Nanoparticle synthesis
KW - Scanning electron microscopy
KW - Driving physical mechanism
KW - Negative charged microparticle
KW - Temperature driven process
PY - 2023
AN - OPUS4-59081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witt, Julia
T1 - Exploring innovative Materials and in situ techniques
N2 - Presentation of some projects conducted in recent years related to corrosion studies and research on electrocatalysis. The talk was part of a seminar at the University of Toronto and took place within the framework of a scientific exchange stay.
T2 - Seminar at the University of Toronto
CY - Toronto, Canada
DA - 11.10.2023
KW - Multi-principal element alloys (MPEAs)
KW - Electrocatalysis
KW - Corrosion
KW - Materials acceleration platforms (MAPs)
PY - 2023
AN - OPUS4-59029
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Hochwertige, verlässliche und FAIRe Daten erstellen: Von Ontologien und elektronischen Laborbüchern zu Datenmanagement und Wissenstransfer
N2 - Das hochaktuelle Thema der Integration und Wiederverwendung von Wissen und Daten aus Herstellung, Bearbeitung und Charakterisierung von Materialien wird im Zuge der digitalen Transformation in der Materialwissenschaft und Werkstofftechnologie in verschiedenen Projekten adressiert. Dabei stehen die Interoperabilität von nach FAIR-Prinzipien erstellten und veröffentlichten Daten und Anwendungen im Vordergrund. Zur Umsetzung eines komplexen Datenmanagements sowie der Digitalisierung im Bereich der Materialwissenschaften etablieren sich Ontologien zunehmend als belastbares Werkzeug. Sie ermöglichen sowohl menschenlesbare als auch maschinenverständliche und -interpretierbare Wissensrepräsentationen durch semantische Konzeptualisierungen.
Im Rahmen des Projektes Plattform MaterialDigital (PMD, materialdigital.de) werden Ontologien verschiedener Ebenen entwickelt (verbindende mid-level sowie Domänen-Ontologien). Die PMD-Kernontologie (PMD Core Ontology - PMDco) ist eine Ontologie der mittleren Ebene), die Verbindungen zwischen spezifischeren MSE-Anwendungsontologien und domänenneutralen Konzepten herstellt, die in bereits etablierten Ontologien höherer Ebenen (top-level Ontology) verwendet werden. Sie stellt somit einen umfassenden Satz von durch Konsensbildung in der Gemeinschaft (geteiltes Vokabular) entstanden Bausteinen grundlegender Konzepte aus der Materialwissenschaft und Werkstofftechnik (MSE) dar. Das primäre Ziel des PMDco-Designs ist es, die Interoperabilität zwischen verschiedenen MSE-bezogenen und anderen Ontologien zu ermöglichen. Die PMDco dient als umfassend ausgelegte und erweiterbare semantische Zwischenschicht, die gemeinsame MSE-Konzepte durch semantisches Mapping auf andere Darstellungen vereinheitlicht, was sie zu einem effizienten Werkzeug zur Strukturierung von MSE-Wissen macht. In dieser Präsentation wird die Version 2.0 der PMDco vorgestellt.
Weiterhin wird eine auf die PMDco bezogene normenkonforme ontologische Repräsentation zur Speicherung und Weiterverarbeitung von Zugversuchsdaten präsentiert, die in enger Zusammenarbeit mit Standardisierungsgremien erstellt wurde. Dies umfasst den Weg von der Entwicklung einer Ontologie nach Norm, der Konvertierung von Daten aus Standardtests in das interoperable RDF-Format bis hin zur Verbindung von Ontologie und Daten. Letztendlich können die entsprechenden Daten in einem Triple Store abgelegt und abgefragt werden. Auf Basis dieser Zugversuchsontologie wurde im Folgenden unter Verwendung eines elektronischen Laborbuches (electonic lab notebook – ELN) zur Datenaufnahme eine Praktikumsreihe von Universitätsstudierenden digitalisiert. Dadurch wurde eine vollständig digital integrierte Versuchsführung ermöglicht, die auf andere Versuchsreihen und Experimente übertragbar ist und ebenfalls vorgestellt werden soll. Neben einer erleichterten Aufnahme, Analyse und (Wieder-)Verwendbarkeit von Daten wird damit eine Sensibilisierung von Studierenden für Datenstrukturierung sowie semantische Technologien im Sinne der Aus- und Weiterbildung erreicht.
T2 - DVM-Tagung Werkstoffprüfung
CY - Berlin, Germany
DA - 23.11.2023
KW - Ontologie
KW - Semantic Web Technologies
KW - Plattform MaterialDigital
KW - PMDco
KW - Zugversuchsontologie
KW - Zugversuch
KW - Elektronisches Laborbuch (ELN)
PY - 2023
AN - OPUS4-59030
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - PMDco: Achieving High-Quality & Reliable FAIR Data
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
In this presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - Kupfer-Symposium
CY - Jena, Germany
DA - 29.11.2023
KW - Ontology
KW - Semantic Web Technologies
KW - Plattform MaterialDigital
KW - PMDco
PY - 2023
AN - OPUS4-59031
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Electron-beam-induced production of gold nanoparticles
N2 - Several studies have shown that the electron beam (e-beam) can be used to create nanomaterials from microparticles in situ in a TEM. However, attempts to produce gold nanoparticles (NPs) on silicon oxide substrate remained to be accomplished. Here, we show that the production of gold NPs is possible by using the e-beam in a SEM, under a set of parameters. The NPs produced present a size gradient along the radial direction. A parameter study shows that the microparticles may: 1) flicker away without producing NPs, 2) fragment to form NPs and/or 3) react with the silicon oxide substrate, depending on the applied current. A hypothesis regarding the driving physical phenomena that lead the microparticles to fragment into NPs is discussed. Fabrication of gold NPs in the SEM provides a more cost-effective option as compared to the established method in the TEM.
T2 - PhD Seminar
CY - Berlin, Germany
DA - 26.11.2023
KW - Electron-beam-induced modification
KW - Gold nanoparticles
KW - Fabrication method
KW - Scanning electron microscope
KW - Nano-assemblies
PY - 2023
AN - OPUS4-59080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drendel, Jan
A1 - Logvinov, Ruslan
A1 - Heinrichsdorff, Frank
A1 - Hilgenberg, Kai
T1 - Simulation-based controlling of local surface temperature in laser powder bed fusion using the process laser
N2 - State-of-the-art laser powder bed fusion (PBF-LB/M) machines allow pre-heating of the substrate plate to reduce stress and improve part quality. However, two major issues have been shown in the past: First, with increasing build height the apparent pre-heat temperature at the surface can deviate drastically from the nominal pre-heat temperature in the substrate plate. Second, even within a single layer the local surface pre-heat temperature can show large gradients due to thermal bottlenecks in the part geometry underneath the top surface. Both lead to unwanted changes in microstructure or defects in the final parts. In this study, a first attempt is taken to show the feasibility of pre-heating the top surface with the onboard laser beam to overcome the mentioned issues. A single layer of a group of three parts built from IN718 to a height of 33.5 mm is pre-heated in a commercially available PBF-LB/M machine to an average steady state surface temperature of 200 °C using the onboard laser beam. The parts are continuously heated, omitting powder deposition and melting step. Temperatures are measured by thermocouples underneath the surface. The experiments are supported by a thermal finite element (FE) model that predicts the temperature field in the parts. When heating the parts uniformly with the laser beam, differences in surface temperatures as large as 170 K are observed. To overcome this inhomogeneity, the heat flux supplied by the laser beam is modulated. An optimized, spatial heat flow distribution is provided by the thermal FE model and translated into a scan pattern that reproduces the optimized heat distribution on the PBF-LB/M machine by locally modulating hatch distance and scan velocity. This successfully reduces the differences in surface temperature to 20 K. Thermographic imaging shows that a homogeneous surface temperature can be achieved despite the localized heat input by the beam. The potential for industrial application of the optimized laser-heating technique is discussed.
KW - Additive Manufacturing
KW - Simulation
KW - Surface temperature
KW - Laser powder bed fusion
PY - 2023
DO - https://doi.org/10.1016/j.addma.2023.103854
SN - 2214-8604
VL - 78
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-58825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Eine digitale QI für die moderne Produktion: Digital Quality Assurance in der Additiven Fertigung
N2 - Der Vortragt stellt den Use Case Additive Fertigung und das zugehörige Reallabor in QI Digital in Kürze vor und zeigt, mit welchen digitalen Tools das Reallabor mit der übergeordneten Plattform QualityX Daten austauscht.
T2 - QI Forum 2023
CY - Berlin, Germany
DA - 10.10.2023
KW - Additive Fertigung
KW - Digitale Qualitätssicherung
KW - QI Digital
PY - 2023
AN - OPUS4-58830
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Cohen, Zina
T1 - Composition Analysis of Writing Materials in Cairo Genizah Documents
N2 - Through the application of scientific methods of analysis to a corpus of medieval manuscripts found in the Cairo Genizah, this work aims to gain a better understanding of the writing materials used by Jewish communities at that time, shedding new light not only on the production of manuscripts in the Middle Ages, but also on the life of those Jewish communities.
KW - Ink analyses
KW - Cairo Genizah
KW - X-Ray fluorescence analyses
KW - Reflectography
KW - Middle Ages
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588642
UR - https://brill.com/display/title/59331
SN - 978-90-04-44887-2
SN - 978-90-04-46935-8
SP - 1
EP - 192
PB - Brill
CY - Leiden & Boston
AN - OPUS4-58864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
A1 - Fähler, Sebastian
T1 - Thermomagnetic generators with magnetocaloric materials for harvesting low grade waste heat
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage.
Here we give an overview on our research, covering both materials and systems. We demonstrate that guiding the magnetic flux with an appropriate topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude. Through a combination of experiments and simulations, we show that a pretzel-like topology results in a sign reversal of the magnetic flux. This avoids the drawbacks of previous designs, namely, magnetic stray fields, hysteresis and complex geometries of the thermomagnetic material.
Though magnetocaloric materials had been the first choice also for thermomagnetic generators, they require some different properties, which we illustrate with Ashby plots for materials selection. Experimentally we compare La-Fe-Co-Si and Gd plates in the same thermomagnetic generator. Furthermore, we discuss corrosion and deterioration under cyclic use is a severe problem occurring during operation. To amend this, composite plates using polymer as a matrix have been suggested previously.
T2 - Dresden Days of Magnetocalorics
CY - Dresden, Germany
DA - 13.11.2023
KW - Thermomagnetic material
KW - Waste heat recovery
KW - Generator
PY - 2023
AN - OPUS4-58865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Ethics in research for PhD students
N2 - The talk gives a short overview and explains basic principles of research ethics for PhD students. We examine the most important principles in the codes of conduct for good scientific practice on EU and national level. Based on these general rules, we give some hands-on practical tips for daily scientific work and discuss in detail one of the fields most susceptible to conflict, the topic of authorship in scientific publications.
T2 - Kick-off meeting ITN USES2
CY - Online meeting
DA - 09.11.2023
KW - Research ethics
KW - PhD training
PY - 2023
AN - OPUS4-58783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cohen, Zina
T1 - Beyond the text: What writing materials of the Cairo Genizah tell us
N2 - Results:
- Four types of inks were measured iron gall (vitriolic and non vitriolic), carbonic, mixed and vegetable inks.
- We need to start analyzing systematically the organic part of the inks.
- Great variety in the composition of the inks.
- No correlation between the type of ink used and any other criteria apart from a personal preference.
- Inks purchased by (some) scribes.
- Reconstruction of the chronology of writing and signing of certain legal documents.
- Comparison with documents written by the Muslim court.
T2 - Ink Workshop
CY - Munich, Germany
DA - 28.06.2022
KW - Ink analyses
KW - Manuscript studies
KW - X-Ray fluorescence analyses
KW - Cairo Genizah
KW - Middle Ages
PY - 2022
UR - https://www.naher-osten.uni-muenchen.de/wasistlosaminstitut/veranstaltungsarchiv/veranstaltungen-2022/inkworkshop/index.html
AN - OPUS4-58874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cohen, Zina
T1 - Étude archéométrique des manuscrits de la Genizah du Caire: Ce que l'encre nous révèle des communautés juives
T1 - Archaeometric study of the Genizah manuscripts of Cairo: What ink reveals to us about Jewish communities
N2 - Conclusion et piste:
Il semblerait qu’il n’existe pas de corrélation entre le type d’encre utilisés et d’autres critères recherchés à part une marque de préférence personnelle, sauf en ce qui concerne des documents religieux, auquel cas une différence se fait en function de la communauté.
Les résultats réunis dans cette étude semble indiquer que les scribes achètent leur propre encre.
L’analyse des encres peut nous aider à retracer une chronologie de l’écriture et signature de certains documents juridiques.
Élargissement du corpus:
- Comparaison avec des documents écrits par la cour du Qadi
- Documents d’autres collections
- Avec d’autres documents contemporains (Génizah Afghane)
N2 - Conclusion and track:
It seems that there is no correlation between the type of ink used and other criteria sought apart from a mark of personal preference, except with regard to religious documents, in which case a difference is made according to the community.
The results gathered in this study seem to indicate that scribes purchased their own ink.
Ink analysis can help us trace a chronology of the writing and signing of certain legal documents.
Corpus expansion:
- Comparison with documents written by the court of the Qadi
- Documents from other collections
- With other contemporary documents (Génizah Afghane)
T2 - Codicologie quantitative et sociologie du livre médiéval : Faire corps par le livre
CY - Paris, France
DA - 31.01.2023
KW - Encre
KW - Genizah du Caire
KW - Archéométrie
KW - Manuscrits
KW - Moyen-âge
PY - 2023
AN - OPUS4-58875
LA - fra
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - PMDco - Platform MaterialDigital Core Ontology: Achieving High-Quality & Reliable FAIR Data
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
In this poster presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures is shown.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - DVM Arbeitskreis Betriebsfestigkeit - Potenziale der Betriebsfestigkeit in Zeiten des technologischen und gesellschaftlichen Wandels
CY - Munich, Germany
DA - 11.10.2023
KW - Digitalization
KW - Semantic Web Technologies
KW - FAIR
KW - Data Interoperability
KW - PMD Core Ontology
PY - 2023
AN - OPUS4-58602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ayerdi Gomez, A.
A1 - Slachciak, Nadine
A1 - Zubia Aranburu, J.
A1 - Zabala, A.
A1 - Aginagalde, A.
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
T1 - Improvement of the tribological performance of titanium alloy using FS-laser-induced periodic surface structures in combination with ZDDP and ionic liquid lubricant additives
N2 - The performance of titanium alloy (Ti6Al4V) surfaces was investigated in lubricated reciprocating sliding tribological tests (RSTT). Special emphasis was laid on the effect of surface nanostructures in area of contact on the respective friction and wear behaviour. These so-called laser-induced periodic surface structures (LIPSS, ripples) were produced on the titanium alloy surface upon scan processing in air by an ultrashort pulsed femtosecond (fs) laser. As lubricant served two types of base oils, a pure polyalcylene-glycol, and an SAE 0W30 oil containing only antioxidants and temperature stabilizers. Tribological tests were carried out on polished as well as LIPSS covered areas using both types of base oil. A test metrics was established, combining the additive 2-ethylhexyl-zincdithiophosphate (ZDDP) or the ionic liquid [P6,6,6,14] [DEHP] (98% purity) with the respective base oils. The test metrics also considered the orientation of motion with respect to the orientation of the structures formed on the surface. Results are presented which show that the interplay between LIPSS and the local chemistry formed by the respective additives is beneficial for the tribological behaviour of the titanium alloy. Certain combinations of base oil, additive and LIPSS reduced friction and wear significantly in the tribological contact.
T2 - 64. Tribologie-Fachtagung
CY - Göttingen, Germany
DA - 25.09.2023
KW - TiAl64V
KW - 100Cr6
KW - Friction
KW - Wear
KW - LIPSS
KW - Lubrication
KW - PAG
KW - Ionic liquid
PY - 2023
SP - 1
EP - 5
AN - OPUS4-58642
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - Influence of the spatial laser energy absorption on the molten pool dynamics in high-power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized level-set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a significant drop in the time-averaged laser energy absorption occurs at the focus position of the laser beam and that the rest of the keyhole region has relatively homogeneous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed. The obtained numerical results are compared with experimental measurements to ensure the validity of the proposed model.
KW - Laser beam welding
KW - Laser energy absorption
KW - Molten pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587531
DO - https://doi.org/10.2351/7.0001078
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 8
PB - AIP Publishing
AN - OPUS4-58753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - Influence of the spatial laser energy absorption on the molten pool dynamics in high-power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized Level-Set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a noticeable drop of the time-averaged laser energy absorption occurs at the focus position of the laser beam, and the rest region of the keyhole has relatively homogenous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of the different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed and compared. The obtained numerical results are compared with experimental measurements to assure the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, USA
DA - 16.10.2023
KW - Laser beam welding
KW - laser energy absorption
KW - molten pool
KW - keyhole dynamics
KW - numerical modeling
PY - 2023
SP - 1
EP - 8
AN - OPUS4-58754
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - The influence of the spatial laser energy absorption on the molten pool dynamics in high power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized Level-Set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a noticeable drop of the time-averaged laser energy absorption occurs at the focus position of the laser beam, and the rest region of the keyhole has relatively homogenous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of the different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed and compared. The obtained numerical results are compared with experimental measurements to assure the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, Illinois, USA
DA - 16.10.2023
KW - Laser beam welding
KW - Laser energy absorption
KW - Molten pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2023
AN - OPUS4-58755
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano, Daniel
A1 - Bulling, Jannis
A1 - Gravenkamp, Hauke
A1 - Birk, Carolin
T1 - Domain decoupling implementation for efficient ultrasonic wave simulations using scaled boundary finite elements and the mortar method
N2 - We introduce a novel approach that combines the scaled boundary finite element method (SBFEM) with a mortar coupling to enhance the computational modelling of elastic wave propagation and interaction with local features in the ultrasonic range. The key objective is to achieve decoupling between different regions of interest, enabling independent meshes for the zones where waves either propagate or interact with localised discontinuities in the elastic media. This decoupling allows us to exploit the benefits offered by various SBFEM formulations. Thus, we can select the most suitable solution for each specific region. An important concept we emphasise is the differentiation between the near field and far field regions. The near field encompasses zones where the precise representation of small features compared to the wavelength is crucial. At the same time, the far field comprises homogeneous regions where the waves propagate without interactions, eventually radiating towards infinity if the domain is unbounded. By separating these two zones, we can improve the computational performance by employing finer discretisation only where necessary. Furthermore, this decoupling enables the reuse of far field models in parametric analyses, making it highly valuable for scenarios focused particularly on local elastic wave interactions. This approach offers considerable potential in such cases. The modelling technique is validated, and its potential is demonstrated through practical applications.
KW - Computer Science Applications
KW - General Physics and Astronomy
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - Computational Mechanics
PY - 2023
DO - https://doi.org/10.1016/j.cma.2023.116465
SN - 0045-7825
VL - 417
IS - Part A
SP - 1
EP - 21
PB - Elsevier BV
AN - OPUS4-58478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - In-situ hot isostatic pressing combined with x-ray imaging and diffraction of laser powder bed fusion ti-6al-4v
N2 - Hot Isostatic Pressing (HIP) is often introduced to tackle the porosity issue in additively manufactured (AM) materials. For instance, HIP post-processing is recommended to improve fatigue resistance of Laser powder bed fusion (PBF-LB) manufactured parts [1, 2]. Even though HIP cannot completely remove porosity, it significantly decreases the defect population and its average size below the critical threshold value leading to early crack initiation.
In the present study, in-situ investigation of HIP procedure of PBF-LB Ti-6Al-4V parts was carried out to gain further insights into the densification mechanism occurring during HIP. The in-situ observations at high pressure and high temperature are uniquely possible at the PSICHE beamline of the Soleil synchrotron (France), thanks to the Ultrafast Tomography on a Paris-Edinburgh Cell (UToPEC) and the combination of the fast phase-contrast tomography and energy-dispersive diffraction [3, 4]. A detailed methodology was developed to ensure that the correct pressure and temperature were maintained during the experiments.
The results allowed an estimation of the global dentification rate during HIP of PBF-LB Ti-Al-4V material, as well as a detailed quantitative characterization of the influence of pore size and shape on the densification process, thereby understanding the effectiveness of HIP process on different pore categories. After 20 mins, 75% of porosity can be considered as closed or has size below the resolution of the XCT reconstruction. We also observed that the smallest defects showed higher densification rate, while the defect shape did not have significant effect on such rate. The current development of in-situ HIP experiment allows experimental quantification and validation of the simulation work. Ultimately it paves the road to tailoring the HIP procedure for different materials depending on the porosity and microstructure.
T2 - AAMS 2023
CY - Madrid, Spain
DA - 26.09.23
KW - Additive manufacturing
KW - HIP
KW - X-ray computed tomography
PY - 2023
AN - OPUS4-58482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
T1 - Entwicklungen bei der Normung von Explosivstoffen und Pyrotechnik
N2 - Vorstellung der aktuellen Arbeiten im CEN/TC 321 und CEN/TC 212 sowie Ausblick auf wesentliche Themen in den Bereichen zivile Explosivstoffe und pyrotechnische Gegenstände. Des Weiteren wird der Normungsauftrag der KOM für die Pyrotechnik vorgestellt und die damit verbundenen Herausforderungen und Möglichkeiten erläutert.
T2 - 20. Sitzung des Sachverständigenausschusses für explosionsgefährliche Stoffe
CY - Berlin, Germany
DA - 18.09.2023
KW - Explosivstoffe
KW - Pyrotechnik
KW - Normungsauftrag
PY - 2023
AN - OPUS4-58621
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
A1 - Hellfritz, Benjamin
A1 - Löffler, Frank
T1 - Digitisation of the quality infrastructure - using the example of additive manufacturing
N2 - Rapidly advancing technologies and progressive digitisation are posing challenges to the established quality infrastructure (QI). In response, the key stakeholders of the German QI established the initiative QI-Digital aimed at developing new solutions for modern quality assurance. One of the central use cases herein is quality assurance for additive manufacturing, in which a fully interlinked additive manufacturing process chain is established. The intention is to collect and process data from each production step, allowing for a comprehensive digital view of the physical material flow. Within this process chain, prototypes of digital QI tools like machine readable standards and digital quality certificates are being demonstrated, tested, and evolved. This is complemented by research on the process level, comprising the evaluation and refinement of methods for in-situ and ex-situ quality assurance, as well as algorithms for registration, reduction, and analysis of process data. This paper presents the status, goals, and vision for the QI-Digital use case additive manufacturing.
T2 - Metal Additive Manufacturing Conference 2023
CY - Wien, Austria
DA - 17.10.2023
KW - Additive Manufacturing
KW - Digitalisation
KW - Quality Assurance
PY - 2023
SP - 96
EP - 104
CY - Wien
AN - OPUS4-58628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitisation of the quality infrastructure - Using the example of additive manufacturing
N2 - Rapidly advancing technologies and progressive digitisation are posing challenges to the established quality infrastructure (QI). In response, the key stakeholders of the German QI established the initiative QI-Digital aimed at developing new solutions for modern quality assurance. One of the central use cases herein is quality assurance for additive manufacturing, in which a fully interlinked additive manufacturing process chain is established. The intention is to collect and process data from each production step, allowing for a comprehensive digital view of the physical material flow. Within this process chain, prototypes of digital QI tools like machine readable standards and digital quality certificates are being demonstrated, tested, and evolved. This is complemented by research on the process level, comprising the evaluation and refinement of methods for in-situ and ex-situ quality assurance, as well as algorithms for registration, reduction, and analysis of process data. This paper presents the status, goals, and vision for the QI-Digital use case additive manufacturing.
T2 - Metal Additive Manufacturing Conference 2023
CY - Vienna, Austria
DA - 17.10.2023
KW - Additive Manufacturing
KW - Digitalisation
KW - Quality Assurance
PY - 2023
AN - OPUS4-58629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Eine digitale QI für die moderne Produktion: Datenbasierte Qualitätssicherung in der Additiven Fertigung
N2 - Als Beispiel für moderne Produktion ist die additive Fertigung (ugs. „3D-Druck“) bei der Herstellung von hochkomplexen metallischen Bauteilen, bionisch inspiriertem Leichtbau oder Prototypen nicht mehr wegzudenken. Die Qualitätssicherung (QS) von Bauteilen für sicherheitskritische Anwendungen stellt jedoch noch eine Herausforderung dar. Die Additive Fertigung (AM) ist ein vergleichsweise junges und datenintensives Fertigungsverfahren. Daher ist es ideal geeignet, die neuen Werkzeuge einer digitalen Qualitätsinfrastruktur (QI) für die moderne Produktion zu erproben und weiterzuentwickeln.
T2 - 2. QI-Digital Forum
CY - Berlin, Germany
DA - 10.10.2023
KW - Additive Manufacturing
KW - Digitalisation
KW - Quality Assurance
PY - 2023
AN - OPUS4-58630
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - “Grabenkorrosion": How scientific debate leads to an solution. and modern failures due to neglection of well described facts
N2 - In the late 1980s, a new type of corrosion appeared in drinking water installations where galvanized steel pipes failed forming a deep groove with no corrosion at the other surfaces. The reason was discussed quite fiercely between failure analysts and material suppliers. In the end the discussion lead to the solution: inductive welded pipes of a certain sulphur content were prone to selective corrosion. The history of the arguments is discussed using old communications between Wilhelm Schwenk and Wolfgang Stichel, who later published the results in a paper unfortunately only I german.
Thus the knowledge got lost and new cases based on the same material problems are observed in application of so-called C-Steel piping systems. Failure cases are shown.
T2 - MTech 2023
CY - Cavtat, Croatia
DA - 02.10.2023
KW - Corrosion
KW - Grabenkorrosion
PY - 2023
SN - 2806-8769
SP - 1
EP - 6
PB - Croatian Society for Heat Treatment and Sufrace Engineering
CY - Zagreb
AN - OPUS4-58521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemiasheuski, Anton
A1 - Bajer, Evgenia
A1 - Oder, Gabriele
A1 - Göbel, Artur
A1 - Hesse, Rene
A1 - Pfennig, A.
A1 - Bettge, Dirk
T1 - Entwicklung eines automatisierten 3D-Metallographie-Systems und erste Beispiele für die Anwendung in der Gefüge-Analyse
T1 - Development of an automated 3D metallography system and some first application examples in microstructural analysis
N2 - Die klassische Metallographie basiert auf Abbildungen einzelner Schliffebenen und kann auf räumliche Formen und Anordnungen des Gefüges nur bedingt schließen. Die Idee, aus metallographischen Serienschliffen dreidimensionale Gefügestrukturen zu rekonstruieren, ist daher naheliegend und nicht neu. Allerdings ist der Aufwand, in Handarbeit viele Einzel-Schliffe zu präparieren und zu Bildstapeln zusammenzusetzen, sehr hoch und steht einer häufigen Anwendung entgegen.
Deshalb wird an der BAM ein Roboter-gestütztes 3D-Metallographie-System entwickelt, das an einer Schliffprobe die Schritte Präparation und Bildeinzug vollautomatisch mit vielen Wiederholungen ausführt. Die Präparation umfasst Schleifen, Polieren und optional Ätzen der Schlifffläche, der Bildeinzug autofokussierte lichtmikroskopische Aufnahmen bei mehreren Vergrößerungsstufen. Der erhaltene Bildstapel wird anschließend vorverarbeitet, segmentiert und in ein 3D-Modell umgesetzt, das einer mikrotomographischen Aufnahme ähnelt, allerdings mit besserer lateraler Auflösung bei großem Volumen. Im Gegensatz zu tomographischen Verfahren besteht die Möglichkeit der Kontrastierung durch klassische chemische Ätzung. Die Integration eines REMs ist geplant. Bislang durchgeführte Arbeiten verdeutlichen die Möglichkeiten der Darstellung von Heißgas-Korrosionsschichten, Grauguss-Werkstoffen und Keramik-basierten mikroelektronischen Strukturen (Vias).
N2 - Traditional metallography relies on the imaging of individual section planes. However, conclusions as to spatial shapes and microstructural arrangements can only be drawn to a limited extent. The idea to reconstruct three-dimensional microstructures from metallographic serial sections is therefore obvious and not at all new. However, the manual process of preparing a great number of individual sections and assembling them into image stacks is time-consuming and laborious and therefore constitutes an obstacle to frequent use. This is why the Federal Institute for Materials Research and Testing, or BAM for short (Bundesanstalt für Materialforschung und -prüfung), is developing a robot-assisted 3D metallography system performing the tasks of preparation and image acquisition on a metallographic section fully automatically and repeatedly. Preparation includes grinding, polishing and optional etching of the section surface. Image acquisition is performed using a light optical microscope with autofocus at several magnification levels. The obtained image stack is then pre-processed, segmented and converted to a 3D model resembling a microtomographic image, but with a higher lateral resolution when large volumes are sampled. As opposed to tomographic techniques, it is possible to perform traditional chemical etching for contrasting. The integration of a SEM is in the planning stages. Studies conducted so far have demonstrated the possibility of visualizing hot gas corrosion layers, grey cast irons and ceramic-based microelectronic structures (vias).
KW - 3D-Metallographie
KW - Gefügeanalyse
KW - Serienschnitte
KW - Gefügerekonstruktion
KW - 3D metallography
KW - Microstructure analysis
KW - Serial sectioning
KW - Microstrucure reconstruction
PY - 2023
DO - https://doi.org/10.1515/pm-2023-0057
SN - 0032-678X
VL - 60
IS - 10
SP - 676
EP - 691
PB - De Gruyter
CY - Berlin/Boston
AN - OPUS4-58593
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Platform MaterialDigital Core Ontology (PMDco): A Community Driven Mid-Level Ontology in the MSE Domain
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - Patents4Science
CY - Berlin, Germany
DA - 05.10.2023
KW - Knowledge Representation
KW - Semantic Interoperability
KW - FAIR data management
KW - Knowledge graph and ontologies
KW - PMD Core Ontology
PY - 2023
AN - OPUS4-58507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Poka, Konstantin
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Integration of the whole digital chain in a unique file for PBF-LB/M: practical implementation within a digital thread and its advantages
N2 - The industrialization of AM is only possible by creating synergy with the tools of Industry 4.0. The system technology of Powder Bed Fusion with Laser beam of Metals (PBF-LB/M) reached a level of high performance in terms of process stability and material spectrum in the past years. However, the digital process chain, starting from CAD via CAM and plant-specific compila-tion of the manufacturing file exhibits media disruptions. The consequence is a loss of metadata. A uniform data scheme of simulation for Design for Additive Manufacturing (DfAM), the PBF-LB/M process itself and quality assurance is currently not realized within industry. There is no entity in the common data flows of the process chains, that enables the integration of these functionalities. As part of the creation of a digital quality infrastructure in the QI-Digital pro-ject, an integration of the CAD/CAM chain is being established. The outcome is a file in an advanced commercially available format which includes all simula-tions and manufacturing instructions. The information depth of this file extends to the level of the scan vectors and allows the automatic optimization and holis-tic documentation. In addition, the KPI for the economic analysis are generated by compressing information into a unique file combined with the application of a digital twin. The implementation and advantages of this solution are demon-strated in a case study on a multi-laser PBF-LB/M system. A build job contain-ing a challenging geometry is thermally simulated, optimized, and manufac-tured. To verify its suitability for an Additive Manufacturing Service Platform (AMSP), the identical production file is transferred to a PBF-LB/M system of another manufacturer. Finally, the achieved quality level of the build job is evaluated via 3D scanning. This evaluation is carried out in the identical entity of the production file to highlight the versatility of this format and to integrate quality assurance data.
T2 - Additive Manufacturing for Products and Applications 2023
CY - Lucerne, Switzerland
DA - 11.09.2023
KW - Laser Powder Bed Fusion
KW - Digital Twin
KW - Data Integrity
KW - Process Chain Integration
KW - Computer Aided Manufacturing
PY - 2023
SN - 978-3-031-42982-8
DO - https://doi.org/10.1007/978-3-031-42983-5_7
SN - 2730-9576
VL - 3
SP - 91
EP - 114
PB - Springer
CY - Cham
AN - OPUS4-58363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
A1 - Rug, Tehseen
A1 - Firdous, Rafia
A1 - Zia, Ghezal Ahmad Jan
A1 - Lüders, Stefan
A1 - Lisdero Scaffino, Horacio
A1 - Höpler, Michael
A1 - Böhmer, Felix
A1 - Pfaff, Matthias
A1 - Stephan, Dietmar
A1 - Kruschwitz, Sabine
T1 - Data driven design of alkali-activated concrete using sequential learning
N2 - This paper presents a novel approach for developing sustainable building materials through Sequential Learning. Data sets with a total of 1367 formulations of different types of alkali-activated building materials, including fly ash and blast furnace slag-based concrete and their respective compressive strength and CO2-footprint, were compiled from the literature to develop and evaluate this approach. Utilizing this data, a comprehensive computational study was undertaken to evaluate the efficacy of the proposed material design methodologies, simulating laboratory conditions reflective of real-world scenarios. The results indicate a significant reduction in development time and lower research costs enabled through predictions with machine learning. This work challenges common practices in data-driven materials development for building materials. Our results show, training data required for data-driven design may be much less than commonly suggested. Further, it is more important to establish a practical design framework than to choose more accurate models. This approach can be immediately implemented into practical applications and can be translated into significant advances in sustainable building materials development.
KW - Sustainable building materials
KW - Sequential learning
KW - Data-driven materials design
KW - Alkali-activated building materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584376
UR - https://www.sciencedirect.com/science/article/pii/S095965262302379X
DO - https://doi.org/10.1016/j.jclepro.2023.138221
SN - 0959-6526
SN - 1879-1786
VL - 418
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-58437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - News from the working area - Semantic Interoperability
N2 - This presentation provides a comprehensive overview of recent developments and the current status within the Semantic Interoperability work area, with a particular emphasis on the advancements related to the Platform MaterialDigital Core Ontology (PMDco). The presentation will delve into the collaborative and community-supported curation process that has been instrumental in shaping PMDco. Additionally, we will introduce the innovative Ontology Playground, showcasing its role in fostering experimentation and exploration within the realm of ontology development.
T2 - MaterialDigital Vollversammlung
CY - Karlsruhe, Germany
DA - 21.09.2023
KW - Semantic Representation
KW - FAIR data management
KW - Semantic Interoperability
KW - Knowledge graph and ontologies
KW - PMD Core Ontology
KW - MaterialDigital
PY - 2023
AN - OPUS4-58422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
A1 - Osterwald, Stephan
A1 - Gerhold, Stefan
T1 - Mess- und Prüfverfahren für Schichten und Schichtsysteme - Der DIN-Normausschuss 062-01-61
N2 - Die Funktionalität von modernen technischen Komponenten liegt meist in der Oberfläche und in Beschichtungen. Das Design und die Herstellungsqualität von Beschichtungen ist essenziell für die optischen, elektrischen, mechanischen und chemischen Eigenschaften von Bauteilen, sowie für den Korrosions- und Verschleißschutz. In diesem Gremium bearbeiten wir Normen für die Qualitätssicherung von dünnen Schichten verschiedener Art. Dabei betrachten wir Eigenschaften wie Schichtdicke, Zusammensetzung, Haltbarkeit, Korrosionsbeständigkeit und physikalische Parameter von dünnen Schichten mit sehr vielfältigen Techniken. Neben klassischen Verfahren aus der Galvanik und Schichtmesstechnik, werden dabei auch neuere spektroskopische Verfahren wie Ellipsometrie und THz-Reflektion bedeutend. Unser Gremium ist offen für neue Mitglieder aus der Oberflächen- und Beschichtungsgemeinschaft.
T2 - ZVO Oberflächentage 2023
CY - Berlin, Germany
DA - 13.09.2023
KW - Dünne Schichten
KW - Galvanotechnik
KW - Metallschichten
KW - Messtechnik
PY - 2023
AN - OPUS4-58432
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
A1 - Heinrichsdorff, F.
A1 - Oster, Simon
A1 - Uhlmann, E.
A1 - Polte, J.
A1 - Gordei, A.
A1 - Hilgenberg, Kai
T1 - In-situ monitoring of the laser powder bed fusion process by thermography, optical tomography and melt pool monitoring for defect detection
N2 - For the wide acceptance of the use of additive manufacturing (AM), it is required to provide reliable testing methods to ensure the safety of the additively manufactured parts. A possible solution could be the deployment of in-situ monitoring during the build process. However, for laser powder bed fusion using metal powders (PBF-LB/M) only a few in-situ monitoring techniques are commercially available (optical tomography, melt pool monitoring), which have not been researched to an extent that allows to guarantee the adherence to strict quality and safety standards.
In this contribution, we present results of a study of PBF-LB/M printed parts made of the nickel-based superalloy Haynes 282. The formation of defects was provoked by local variations of the process parameters and monitored by thermography, optical tomography and melt pool monitoring. Afterwards, the defects were characterized by computed tomography (CT) to identify the detection limits of the used in-situ techniques.
T2 - Lasers in Manufacturing Conference 2023
CY - Munich, Germany
DA - 26.06.2023
KW - Thermography
KW - Optical tomography
KW - Melt-pool-monitoring
KW - Laser powder bed fusion
KW - Haynes 282
KW - Additive Manufacturing
PY - 2023
UR - https://www.wlt.de/lim2023-proceedings/system-engineering-and-process-control
SP - 1
EP - 10
AN - OPUS4-58466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
A1 - Schmies, Lennart
T1 - Die Fraktographische Online-Datenbank der AG Fraktographie – Entwicklungsstand und weitere Planung
N2 - Vortrag zum aktuellen Stand der fraktographischen online-Datenbank. Darstellung des AGM/DVM Gemeinschaftsausschusses REM in der Materialforschung und seiner Arbeitsgruppen Fraktographie, EBSD und 2D/3D-Prüfung. Ziele und Inhalte der fraktographischen Datenbank, Aufruf zum Mitmachen. Durchführung von Vergleichsversuchen, Entwicklung einer fraktographischen Symbolik, Ringversuch, Vorhaben iFrakto mit Entwicklung einer KI-gestützten Bruchflächenanalyse.
T2 - Metallographietagung 2023
CY - Leoben, Austria
DA - 13.09.2023
KW - Fraktographie
KW - Machine Learning
KW - Datenbank
PY - 2023
AN - OPUS4-58467
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Tabasco-Novelo, Carolina
A1 - Quintana, Patricia
A1 - Rodriguez-Gattorno, Geonel
A1 - Alvarado-Gil, Juan J.
T1 - Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions
N2 - In this work, the thermal properties of ternary Li₃ₓCo₇₋₄ₓSb₂₊ₓO₁₂ solid solutions are studied for different concentrations in the range 0 ≤ x ≤ 0.7. Samples are elaborated at four different sintering temperatures: 1100, 1150, 1200 and 1250 °C. The effect of increasing the content of Li⁺ and Sb⁵⁺, accompanied by the reduction of Co²⁺, on the thermal properties is studied. It is shown that a thermal diffusivity gap, which is more pronounced for low values of x, can be triggered at a certain threshold sintering temperature (around 1150 °C in this study). This effect is explained by the increase of contact area between adjacent grains. Nevertheless, this effect is found to be less pronounced in the thermal conductivity. Moreover, a new framework for heat diffusion in solids is presented that establishes that both the heat flux and the thermal energy (or heat) satisfy a diffusion equation and therefore highlights the importance of thermal diffusivity in transient heat conduction phenomena.
KW - General Chemical Engineering
KW - General Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593248
DO - https://doi.org/10.1021/acsomega.2c07557
SN - 2470-1343
VL - 8
IS - 8
SP - 7808
EP - 7815
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-59324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmies, Lennart
A1 - Botsch, B.
A1 - Le, Q.-H.
A1 - Yarysh, A.
A1 - Sonntag, U.
A1 - Hemmleb, M.
A1 - Bettge, Dirk
T1 - Classification of fracture characteristics and fracture mechanisms using deep learning and topography data
T1 - Klassifikation von Bruchmerkmalen und Bruchmechanismen mittels Deep Learning und unter Verwendung von Topographiedaten
N2 - In failure analysis, micro-fractographic analysis of fracture surfaces is usually performed based on practical knowledge which is gained from available studies, own comparative tests, from the literature, as well as online databases. Based on comparisons with already existing images, fracture mechanisms are determined qualitatively. These images are mostly two-dimensional and obtained by light optical and scanning electron imaging techniques. So far, quantitative assessments have been limited to macrocopically determined percentages of fracture types or to the manual measurement of fatigue striations, for example. Recently, more and more approaches relying on computer algorithms have been taken, with algorithms capable of finding and classifying differently structured fracture characteristics. For the Industrial Collective Research (Industrielle Gemeinschaftsforschung, IGF) project “iFrakto” presented in this paper, electron-optical images are obtained, from which topographic information is calculated. This topographic information is analyzed together with the conventional 2D images. Analytical algorithms and deep learning are used to analyze and evaluate fracture characteristics and are linked to information from a fractography database. The most important aim is to provide software aiding in the application of fractography for failure analysis. This paper will present some first results of the project.
N2 - Die mikrofraktographische Analyse von Bruchflächen wird in der Schadensanalyse meist auf der Basis von Erfahrungswissen vorgenommen, welches aus vorliegenden Untersuchungen, eigenen Vergleichsversuchen und aus der Literatur und online Datenbanken stammt. Durch Vergleiche mit bereits vorliegenden Bildern werden qualitativ Bruchmechanismen ermittelt. Grundlage dafür sind zumeist zweidimensionale Aufnahmen aus licht- und elektronenoptischen Verfahren. Quantitative Aussagen beschränken sich bislang beispielsweise auf makroskopische Anteile von Bruchmechanismen oder die manuelle Ausmessung von Schwingstreifen. In jüngerer Zeit gibt es vermehrt Ansätze, Computer-Algorithmen einzusetzen, die in der Lage sind, unterschiedlich strukturierte Bruchmerkmale zu finden und zu klassifizieren. Im hier vorgestellten IGF-Vorhaben „iFrakto“ werden elektronenoptische Aufnahmen erzeugt und daraus Topographie-Informationen berechnet. Diese gewonnenen Topographie-Informationen werden zusammen mit den klassischen 2D-Bildern ausgewertet. Analytische Algorithmen und Deep Learning werden eingesetzt, um Bruchmerkmale zu analysieren, zu bewerten und mit Informationen aus einer fraktographischen Datenbank zu verknüpfen. Wichtigstes Ziel ist die Bereitstellung von Software zur Unterstützung der Fraktographie in der Schadensanalyse. In diesem Beitrag werden erste Ergebnisse des Vorhabens vorgestellt.
KW - Fractography
KW - Deep Learning
KW - Classification
PY - 2023
DO - https://doi.org/10.1515/pm-2022-1008
SN - 0032-678X
VL - 60
IS - 2
SP - 76
EP - 92
PB - De Gruyter
AN - OPUS4-56962
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ghafafian, Carineh
A1 - Trappe, Volker
ED - Vassilopoulos, A. P.
ED - Michaud, V.
T1 - Fully-reversed fatigue behavior of scarf joint repairs for wind turbine blade shell applications
N2 - To enable a quick and cost-effective return to service for wind turbine blades, localized repairs can be executed by technicians in the field. Scarf repairs, shown to be highly efficient with a smooth load transition across angled joint walls and a restored aerodynamic profile, are the focus of this work. The failure mechanisms of these structures were examined under quasi-static tensile and fully-reversed cyclic loading. While the scarf ratio was held constant at 1:50, the repair layup was varied between large-to-small and small-to-large. The effect of the presence of resin pockets and the fiber orientation mismatch between parent and repair material on the restored strength of BIAX ±45° glass fiber reinforced polymer scarf joint structures was studied.
T2 - 20th European Conference on Composite Materials
CY - Lausanne, Switzerland
DA - 26.06.2022
KW - Fatigue
KW - Scarf repairs
KW - Glass fiber reinforced polymers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569646
UR - https://infoscience.epfl.ch/record/298799
SN - 978-2-9701614-0-0
VL - Vol. 5 - Applications and structures
SP - 195
EP - 201
PB - Composite Construction Laboratory (CCLab)
CY - Lausanne
AN - OPUS4-56964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, X.
A1 - Shi, L.
A1 - Wu, C.
A1 - Yang, Chunliang
A1 - Gao, S.
T1 - Multi-phase modelling of heat and mass transfer during Ti/Al dissimilar friction stir welding process
N2 - Friction stir welding (FSW) has the capacity to join the Al/Ti dissimilar structures with superior mechanical properties. The microstructures and mechanical characteristics of Al/Ti dissimilar FSW joints are determined by the heat and mass transfer during the welding process. However, a quantitative study of the Al/Ti dissimilar FSW process is lacking. Therefore, using the computational fluid dynamics (CFD) and volume of fluid (VOF) approach, a multi-phase model was constructed for quantitatively analyzing the heat and mass transfer behaviour in dissimilar FSW of TC4 titanium alloy and AA2024-T4 aluminium alloy. The mixed material was treated as a functionally graded material (FGM) to compute the thermophysical characteristics at the weld nugget zone (WNZ). Due to the vast disparity in the thermophysical characteristics of aluminum and titanium alloy, the temperature field in Al/Ti dissimilar FSW was severely asymmetric. The temperature of titanium alloy on the advancing side (AS) was higher than that of aluminium alloy on the retreating side (RS) at the same distance from the tool centre line near the tool shoulder, but it was lower than that of aluminium alloy on the RS without the influence of the shoulder. Due to the high flow stress of titanium alloy, plastic material flow mostly occurred on the RS of aluminium alloy in the Al/Ti dissimilar FSW, with its percentage exceeding 80%. This model was validated by experiment results.
KW - Dissimilar friction stir welding
KW - Al/Ti dissimilar joints
KW - Temperature distribution
KW - Heat generation
KW - Plastic material flow
PY - 2023
DO - https://doi.org/10.1016/j.jmapro.2023.03.037
SN - 2212-4616
VL - 94
SP - 240
EP - 254
PB - Elsevier Ltd.
AN - OPUS4-57265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cysne Barbosa, Ana Paula
A1 - Azevedo do Nascimento, Allana
A1 - Pavasarytė, Lina
A1 - Trappe, Volker
A1 - Melo, D.
T1 - Effect of addition of thermoplastic self-healing agent on fracture toughness of epoxy
N2 - Self-healing agents have the potential to restore mechanical properties and extend service life of composite materials. Thermoplastic healing agents have been extensively investigated for this purpose in epoxy matrix composites due to their strong adhesion to epoxy and their ability to fill in microcracks. One of the most
investigated thermoplastic additives for this purpose is poly(ethylene-co-methacrylic acid) (EMAA). Despite the ability of thermoplastic healing agents to restore mechanical properties, it is important to assess how the addition of thermoplastic healing agents affect properties of the original epoxy material. In this work, EMAA was added to epoxy resin and the effect of the additive on fracture toughness of epoxy was evaluated. Results indicate that although added in low concentrations, EMAA can affect fracture toughness.
T2 - 6th Brazilian Conference on Composite Materials
CY - Tiradentes, Minas Gerais, Brazil
DA - 14.08.2022
KW - Epoxy
KW - Self-healing
KW - Thermoplastic
KW - Fracture
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572707
SN - 978-65-00-49386-3
DO - https://doi.org/10.29327/566492
SN - 2316-1337
SP - 219
EP - 222
AN - OPUS4-57270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matamoros-Veloza, A.
A1 - Stawski, Tomasz
A1 - Vargas, S.
A1 - Neville, A.
T1 - Study of a Local Structure at the Interface between Corrosion Films and Carbon Steel Surface in Undersaturated CO2 Environments
N2 - Industries transporting CO2 gas-saturated fluids have infrastructures made of carbon steel. This is a good material with great mechanical properties but prone to corrosion and potential failure. Corrosion in sweet environments involves the formation of FeCO3 as a corrosion film, which is recognized to play a protective role under certain conditions. This work on the dissolution of corrosion films in sweet environments, under acidic and undersaturated conditions, demonstrates that the effects on the integrity of steel are far more significant than the damage observed on the surface of the corrosion film. Our results prove that dissolution of FeCO3 involved the presence of an amorphous phase, the intermediate formation of FeCl2 or FeCl+, and the presence of a phase with short distance atom–atom correlations. The amorphous phase was identified as a mixture of retained γ-Fe and Fe3C. Partially broken α-Fe and Fe3C structures were identified to prove the damage on the material, confirming the interface zone without evident damage on the corrosion film. Dissolution affected both the α-Fe and FeCO3, with the lattice [102̅] from the FeCO3 crystalline structure being the fastest to dissolve. The damage of steel at the molecular scale was evident at the macroscale with pit depths of up to 250 μm. The impact on the integrity of steel can be, therefore, more drastic than frequently reported in industrial operations of CO2 transport industries that use cleaning procedures (e.g., acid treatment, pigging) as part of their operational activities.
KW - Steel
KW - Corrosion
KW - Siderite
KW - Diffraction
KW - Pair distribution function
KW - Synchrotron
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572156
DO - https://doi.org/10.1021/acsomega.2c07631
SN - 2470-1343
VL - 8
IS - 9
SP - 8497
EP - 8504
PB - ACS
AN - OPUS4-57215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chambers, Aaron
T1 - Synthesis of ZIF nanoparticles with functionalisation towards effective composite formation
N2 - A presentation on functionalising ZIF-8 nanoparticles for composite formation. Characterisation data for the nanoparticles is shown.
T2 - Materials Chemistry Seminar
CY - Online meeting
DA - 23.02.23
KW - MOF composite
KW - Nanoparticles
KW - ZIF-8
PY - 2023
AN - OPUS4-57210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winterkorn, René
T1 - WAAM dickwandiger Bauteile aus höherfesten AL-MG-SI Legierungen
N2 - Das Wire and Arc Additive Manufacturing (WAAM) ist dank hoher erreichbarer Aufbauraten prädestiniert für die Fertigung großvolumiger Bauteile. Dabei ist auf die Wirkmechanismen zwischen Prozessparametern und den daraus resultierenden mechanisch-technologischen Eigenschaften zu achten. Dies gilt insbesondere für die Fertigung dickwandiger Bauteile aus Al-Mg-Si-Aluminiumlegierungen, die eine hohe Anfälligkeit gegenüber Erstarrungsrissen und wasserstoffinduzierter Porosität aufweisen. Der Einfluss der Prozessparameter und des resultierenden Temperaturregimes auf die Bauteilqualität wurde durch die Analyse der Größe und Verteilung von Poren sowie der resultierenden Festigkeit untersucht. Darüber hinaus wurde der Einfluss einer Wärmenachbehandlungsstrategien auf das Festigkeitsverhalten analysiert.
T2 - Additive Fertigung – Werkstoffe – Prozesse – Wärmebehandlung 2022
CY - Bremen, Germany
DA - 29.06.2022
KW - WAAM
KW - AlMgSi Legierungen
KW - Wärmenachbehandlung
KW - Mechanische Eigenschaften
PY - 2022
AN - OPUS4-56672
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
A1 - Kruschwitz, Sabine
T1 - Accelerating the search for sustainable concretes with AI
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders, part of the energy-intensive clinker production process can be dispensed. However, as numerous raw materials are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced binder formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of alkali-activated binder formulations can significantly accelerate research.
The "Sequential Learning App for Materials Discovery" (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings.
Our material database already includes more than 120,000 data points of alternative binders and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials.
Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
T2 - fib International Congress
CY - Oslo, Norway
DA - 12.06.2022
KW - Machine Learning
KW - Materials Design
KW - Sequential Learning
KW - Materials Discovery
KW - Concrete
PY - 2022
AN - OPUS4-56635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
T1 - SLAMD-FIB-Case-Study
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders part of the energy-intensive clinker production process can be dispensed with. However, because numerous chemicals are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced cement formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of cement formulations can significantly accelerate research. The „Sequential Learning App for Materials Discovery“ (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings. Our material database already includes more than 120,000 data points of alternative cements and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials. Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
KW - Alkali activated concrete
KW - Concrete
PY - 2022
UR - https://github.com/BAMcvoelker/SLAMD-FIB-Case-Study#slamd-fib-case-study
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-56637
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
T1 - Discovering climate-friendly building materials with AI
N2 - High greenhouse gas emissions from the production of building materials are a major contributor to the current climate crisis. However, developing alternative building materials is complex. Traditional laboratory methods are reaching their limits. Artificial intelligence, on the other hand, can give research a new dynamic.
Novel materials are usually developed manually in the laboratory rather than on a computer. This makes the processes time-consuming, difficult and expensive. With the app SLAMD (Sequential Learning App for Materials Discovery), materials researchers can explore the potential of artificial intelligence to speed up materials research and easily apply AI in the lab. The app was developed by our team at the Federal Institute for Materials Research and Testing (BAM) led by Prof. Sabine Kruschwitz together with a team in the Department of Building Materials and Construction Chemistry at TU Berlin led by Prof. Dietmar Stephan.
It uses material composition and characterization data to predict ideal material candidates. It can be used to optimize many material properties simultaneously and even incorporates database information such as carbon footprint, material cost or resource availability. Unlike the usual data-intensive AI methods, SLAMD optimally integrates existing knowledge and human feedback, and provides numerous decision support tools to precisely navigate complex scientific knowledge processes towards success.
In this talk, we will present some case studies where we were able to find suitable advanced materials in a few months instead of several years. We will talk about the challenges we overcame and the future potential we see for this approach to developing the green materials of the future.
T2 - Chemometrics meets Artificial Intelligence
CY - Berlin, Germany
DA - 01.04.2022
KW - Machine Learning
KW - Materials Informatics
KW - Sequential Learning
KW - Alkali activated concrete
PY - 2022
AN - OPUS4-56638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Völker, Christoph
T1 - Accelerating the search for sustainable concretes with AI
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders, part of the energy-intensive clinker production process can be dispensed. However, as numerous raw materials are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced binder formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of alkali-activated binder formulations can significantly accelerate research.
The "Sequential Learning App for Materials Discovery" (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings.
Our material database already includes more than 120,000 data points of alternative binders and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials.
Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
KW - Materials informatics
KW - Materials design
KW - Alkali activated concrete
KW - Machine learning
PY - 2022
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-56639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghafafian, Carineh
A1 - Trappe, Volker
T1 - Prolonging structural integrity—Fatigue of scarf repairs for wind turbine blade shell applications
N2 - The influence of scarf repair variables on the mechanical properties of glass fiber reinforced polymer sandwich structures is examined for the application of wind turbine blade shell repairs. Reference shell specimens are tested under fully-reversed cyclic loading to understand the fatigue behavior of the sub-component structure within a range of in-service loads, to which shell specimens with a scarf joint repair are compared. A fatiguesuperior repair material is shown to improve the fatigue behavior of the repaired structures compared to the reference specimens. In separating layup and geometry, damage development is examined on the subcomponent scale for a structural understanding of a scarf repair using in-situ digital image correlation-based strain field measurements as well as passive thermography. Within scarf repair variables, the geometry is shown to play a larger role than layup in the fatigue performance of the repaired structure.
KW - Polymer–matrix composites
KW - Fatigue
KW - Joints/joining
PY - 2023
DO - https://doi.org/10.1016/j.compositesa.2022.107419
SN - 1359-835X
VL - 167
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-56942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced periodic surface structures: mechanisms, applications, and unsolved problems
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation.
From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc.
This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
Fourth generation light sources, namely short wavelength, short pulse free electron lasers (FELs) are offering new and fascinating possibilities to resolve laser-induced structure formation at surfaces on the sub-micrometer to nanometer length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution. This unique spatio-temporal resolution allows to reveal early signatures of coherent/plasmonic electromagnetic scattering effects followed by the excitation of hydrodynamic capillary waves – providing new insights to the above-mentioned debate.
Finally, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. While the currently available laser and scanner technology already allows large area surface processing with rates at the m2/min level, industrial applications of LIPSS are sometimes limited by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. Strategies for overcoming such limitations are outlined.
T2 - Institutskolloquium des Leibniz-Instituts für Oberflächenmodifizierung
CY - Leipzig, Germany
DA - 02.02.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Industrial applications
KW - Femtosecond laser
PY - 2023
AN - OPUS4-56949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, P.
A1 - Chakraborty, Gouri
A1 - Roeser, J.
A1 - Vogl, S.
A1 - Rabeah, J.
A1 - Thomas, A.
T1 - Integrating Bifunctionality and Chemical Stability in Covalent Organic Frameworks via One-Pot Multicomponent Reactions for Solar-Driven H2O2 Production
N2 - Multicomponent reactions (MCRs) can be used to introduce different functionalities into highly stable covalent organic frameworks (COFs). In this work, the irreversible three-component Doebner reaction is utilized to synthesize four chemically stable quinoline-4-carboxylic acid DMCR-COFs (DMCR-1−3 and DMCR-1NH) equipped with an acid−base bifunctionality. These DMCR-COFs show superior photocatalytic H2O2 evolution (one of the most important industrial oxidants) compared to the imine COF analogue (Imine-1). This is achieved with sacrificial oxidants but also in pure water and under an oxygen or air atmosphere. Furthermore, the DMCR-COFs show high photostability, durability, and recyclability. MCR-COFs thus provide a viable materials’ platform for solar to chemical energy conversion.
KW - Reactions
KW - Bifunctionality
KW - Postsynthetic modification
KW - Multicomponent
PY - 2022
DO - https://doi.org/10.1021/jacs.2c11454
SN - 0002-7863
VL - 145
IS - 5
SP - 2975
EP - 2984
PB - ACS Publications
AN - OPUS4-56922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Sachs, Patrick
ED - Vassilopoulos, A. P.
ED - Michaud, V.
T1 - Dynamic mechanical analysis of epoxy-matrix cross linking measured in-situ using an elastomer container
N2 - A new patented dynamic mechanical analysis (DMA) is presented, where the tensile, bending- or torsional stiffness of a media can be characterized in-situ during the phase transition from liquid to solid. An epoxy system, e.g. Hexion L285/H287, is filled into an elastomer container, such as a silicone tube. This can be mounted into a conventional OMA and, based on a linear viscoelastic approach, the storage modulus (E';G'), the loss modulus (E'';G'') and the loss angle tan(δ) can be measured at constant temperature as a function of time in order to investigate the liquid to sol-gel to solid transition. With this new method, the stiffness increase as a result of the cure process can be directly measured more precisely than with a rheometer in a shear plate set-up, because using an elastomer container gives a defined cross section for calculating the Young's modulus.
T2 - 20th European Conference on Composite Materials
CY - Lausanne, Switzerland
DA - 26.06.2022
KW - Cross linking
KW - Dynamic mechanical analysis (DMA)
KW - Thermoset polymers
KW - Cure process
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569651
UR - https://infoscience.epfl.ch/record/298799
SN - 978-2-9701614-0-0
VL - Vol. 5 - Applications and structures
SP - 181
EP - 186
PB - Composite Construction Laboratory (CCLab)
CY - Lausanne
AN - OPUS4-56965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Azevedo do Nascimento, A.
A1 - Trappe, Volker
A1 - Diniz Melo, J. D.
A1 - Cysne Barbosa, A. P.
T1 - Fatigue behavior of self-healing glass fiber/epoxy composites with addition of poly (ethylene-co-methacrylic acid) (EMAA)
N2 - The interest in repair technologies for polymer composites has increased significantly over the last decades, due to the growing use of these materials in structural applications. In this study, poly (ethylene-co-methacrylic acid) (EMAA) was used as self-healing agent to glass fiber/epoxy composite. Materials with EMAA contents of 2 wt% and 5 wt% were manufactured using Resin Transfer Molding (RTM) and the effects of the healing agent on the properties were investigated using tensile tests and Dynamic Mechanical Analysis (DMA). Results show slight variation of properties, which was more pronounced as the content of EMAA increased. In addition, the healing efficiency was investigated through fatigue tests and the addition of higher content of EMAA increased the number of cycles to failure after the healing activation cycle.
KW - Fatigue
KW - Glass fiber-epoxy composites
KW - Self-healing
KW - Smart materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569661
DO - https://doi.org/10.1016/j.polymertesting.2022.107863
SN - 0142-9418
VL - 117
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-56966
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lunkenheimer, P.
A1 - Loidl, A.
A1 - Riechers, Birte
A1 - Zaccone, A.
A1 - Samwer, K.
T1 - Thermal expansion and the glass transition
N2 - Melting is well understood in terms of the Lindemann criterion, which
essentially states that crystalline materials melt when the thermal vibrationsof their atoms become so vigorous that they shake themselves free of the binding forces. This picture does not necessarily have to hold for glasses, where the nature of the solid–liquid cross-over is highly debated. The Lindemann criterion implies that the thermal expansion coefficients of crystals are inversely proportional to their melting temperatures. Here we find that, in contrast, the thermal expansion coefficient of glasses decreases more strongly with increasing glass temperature, which marks the liquid–solid cross-over in this material class. However, this proportionality returns when the thermal expansion coefficient is scaled by the fragility, a measure of particle cooperativity. Therefore, for a glass to become liquid, it is not sufficient to simply overcome the interparticle binding energies.
Instead, more energy must be invested to break up the typical cooperative particle network that is common to glassy materials. The thermal expansion coefficient of the liquid phase reveals similar anomalous behaviour and is universally enhanced by a constant factor of approximately 3. These universalities allow the estimation of glass temperatures from thermal expansion and vice versa.
KW - Glass transition
KW - Lindemann criterion
KW - Thermal expansion
KW - Glass
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570267
DO - https://doi.org/10.1038/s41567-022-01920-5
SN - 1745-2473
SP - 1
EP - 7
PB - Nature Publishing Group
CY - London
AN - OPUS4-57026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Kun
A1 - Pan, L.
A1 - Li, J.
A1 - Lin, C.
T1 - What is the mechanism of the fiber effect on the rheological behavior of cement paste with polycarboxylate superplasticizer?
N2 - Compared with most common construction materials, fiber reinforced cementitious materials are well known to exhibit better physical, working and mechanical properties. In this study, three fibers were selected: polypropylene fiber (PPF) and polyvinyl alcohol fiber (PVAF), which represented synthetic fibers, and sisal fiber (SF), which represented natural fibers. Effects of these fibers on the flowability, rheological properties, and adsorption behavior of the cement paste with polycarboxylate superplasticizer (PCE) were investigated. Furthermore, the above experimental results were verified by measuring the contact angle of the fiber with water and PCE solution and the apparent morphology of the fiber. Results revealed that the addition of fibers significantly reduces the fluidity of the cement paste, while the yield stress and plastic viscosity of the cement paste increase with the addition of fibers. From the contact angle and scanning electron microscope, the surface of SF was relatively rough, and the contact angle of SF with water or PCE solution was the smallest. It can be concluded that the plant fiber has a significant influence on the fluidity and rheology of cement paste.
KW - Cement paste
KW - Polycarboxylate superplasticizer
KW - Polypropylene fiber
KW - Polyvinyl alcohol fiber
KW - Sisal fiber
KW - Rheological property
KW - Fluidity
KW - Adsorption
PY - 2021
DO - https://doi.org/10.1016/j.conbuildmat.2021.122542
SN - 0950-0618
VL - 281
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Editorial: Special Issue “Advanced Pulse Laser Machining Technology"
N2 - “Advanced Pulse Laser Machining Technology” is a rapidly growing field that can be tailored to special industrial and scientific applications. This is significantly driven by the availability of high-repetition-rate laser sources and novel beam delivery concepts.
KW - Editorial
KW - Pulse Laser
KW - Laser Machining
KW - Ultrashort laser pulses
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568410
DO - https://doi.org/10.3390/ma16020819
SN - 1996-1944
VL - 16
IS - 2
SP - 1
EP - 4
PB - MDPI
CY - Basel
AN - OPUS4-56841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Krüger, Jörg
ED - Bonse, Jörn
T1 - Special Issue "Advanced Pulse Laser Machining Technology"
N2 - Advanced Pulse Laser Machining Technology is a rapidly growing field to tailor special industrial and scientific applications. This is significantly driven by the availability of high-repetition rate laser sources and novel beam delivery concepts.
This Special Issue focuses on developments in areas of surface and volume laser material processing, including spatial and temporal beam shaping, Bessel-beam dicing, direct laser interference patterning (DLIP), laser-induced forward transfer (LIFT), pulse burst machining, waveguide writing, and two-photon polymerization. Additionally, limitations of modern laser processing caused by failure of laser optics or unwanted secondary hazards like X-ray emission are addressed.
Here, we would like to attract contributors from industry and academics. This Special Issue shall bundle original research and review articles of the latest achievements.
KW - Advanced ultrashort-laser technology
KW - Bessel-beam laser dicing
KW - Direct laser interference patterning (DLIP)
KW - High-repetition rate ultrafast laser processing
KW - Laser-induced forward transfer (LIFT)
KW - X-ray hazards during ultrafast laser processing
KW - Volume processing, waveguide writing
KW - Temporal beam shaping for precision machining
PY - 2023
UR - https://www.mdpi.com/journal/materials/special_issues/pulse_laser_machining
SN - 1996-1944
PB - MDPI
CY - Basel
AN - OPUS4-56842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - 3D imaging and residual stress analysis for AM Materials
N2 - The overview of the activity of Federal Institute for Material Research and Testing (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The research of our group is focused on the 3D imaging of AM materials by means of X-ray Computed Tomography at the lab and at synchrotron, and the residual stress characterization by diffraction (nondestructive technique).
T2 - Seminar at Integrated Additive Manufacturing center, Politecnico Torino
CY - Turin, Italy
DA - 14.02.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Residual stress
KW - Computed tomography
KW - Synchrotron X-ray diffraction
PY - 2023
AN - OPUS4-57047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kraft, Sebastian
A1 - Schille, J.
A1 - Bonse, Jörn
A1 - Löschner, U.
A1 - Krüger, Jörg
T1 - X‑ray emission during the ablative processing of biological materials by ultrashort laser pulses
N2 - The ablative laser processing with ultrashort pulsed laser beams may cause secondary emission of hazardous X-rays. While the effect has recently been proven to be considered in working safety regulations when processing technical materials, such as metals, the X-ray emission rates during the ablative processing of biological tissue materials are widely unexplored yet.
Therefore, biological materials like water, isotonic saline solution, pig eyes, and human teeth were ablated with ultrashort laser pulses of 1030 nm wavelength, 600 fs pulse duration and 5 kHz pulse repetition rate, aiming to mimic typical surgery situations. Simultaneously, in-situ X-ray dose rate measurements were performed at a short distance from the plasma to display potential X-ray emission. For all four studied biological materials, our measurements prove the secondary emission of laser-induced X-rays.
KW - Ultrashort pulsed laser
KW - Laser-induced X-ray emission
KW - Ophthalmology
KW - Dentistry
KW - Secondary hazard
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569960
DO - https://doi.org/10.1007/s00339-023-06440-4
SN - 0947-8396
VL - 129
IS - 3
SP - 1
EP - 8
PB - Springer
AN - OPUS4-56996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dengel, Jörg
T1 - Geschäftsbericht der Konformitätsbewertungsstelle Explosivstoffe / Pyrotechnik
N2 - Übersicht über aktuelle Themen, Probleme, Herausforderungen und Entscheidungen als benannte Stelle für Pyrotechnik nach 2013/29/EU und Explosivstoffe nach 2014/28/EU.
T2 - 25. Sitzung des Beirats der BAM-Zertifizierungsstelle (BZS)
CY - Berlin, Germany
DA - 14.02.2023
KW - UKCA
KW - Konformitätsbewertung
KW - Statistik
KW - Brexit
KW - Normung
KW - Audit
PY - 2023
AN - OPUS4-56997
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Würth, Christian
T1 - Time resolved spectroscopy of upconverting lanthanide based upconversion nanocrystals
N2 - The optical properties of these materials strongly depend on the excitation power density, i.e., the number of photons absorbed per time interval. The upconversion quantum efficiencies (ΦUC) of these materials, the excitation power dependent population i.e. the emission characteristics, and the deactivation dynamics are influenced by nanoparticle architecture, doping concentration, and the microenvironment. We will discuss how time resolved measurements can help to understand the fundamental photophysical mechanisms and discuss differences to other nanocrystals like quantum dots.
T2 - 19th International Course on “Principles and Applications of Time-resolved Fluorescence Spectroscopy”
CY - Berlin, Germany
DA - 16.11.2022
KW - Nanoparticle
KW - Lanthanide
KW - Upconversion
KW - Energy transfer
PY - 2022
AN - OPUS4-57000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, M.
A1 - Schlingmann, T.
A1 - Schmidt, J.
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
A1 - Binder, M.
A1 - Klöden, B.
T1 - A Round Robin Test To Investigate The Printing Quality Of PBF LB/M Processed AlSi10Mg
N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail.
T2 - World PM2022
CY - Lyon, France
DA - 09.10.2022
KW - Additive manufacturing
KW - AlSi10Mg
KW - Laser powder bed fusion
KW - Round robin
KW - Reproducibility
PY - 2022
AN - OPUS4-56303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, M.
A1 - Schlingmann, T.
A1 - Schmidt, J.
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
A1 - Binder, M.
A1 - Klöden, B.
T1 - A Round Robin Test To Investigate The Printing Quality Of PBF-LB/M Processed AlSi10Mg
N2 - When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial Additive Manufacturing (AM) standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the AM process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB/M process. Differences of the results between the partners and the scatter itself were discussed in detail.
T2 - World PM2022
CY - Lyon, France
DA - 09.10.2022
KW - Additive manufacturing
KW - Round robin
KW - Reproducibility
KW - Laser powder bed fusion
KW - AlSi10Mg
PY - 2022
SN - 978-1-899072-54-5
SP - 1
EP - 10
PB - European Powder Metallurgy Association (EPMA)
AN - OPUS4-56304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macková, A.
A1 - Jagerová, A.
A1 - Lailik, O.
A1 - Miksová, R.
A1 - Poustka, D.
A1 - Mistrík, J.
A1 - Holý, V.
A1 - Schütter, Jan David
A1 - Kentsch, U.
A1 - Marvan, P.
A1 - Azarov, A.
A1 - Galeckas, A.
T1 - Combined Au/Ag nanoparticle creation in ZnO nanopillars by ion implantation for optical response modulation and photocatalysis
N2 - ZnO nanopillars were implanted with Au-400 keV and Ag-252 keV ions with ion fluences from 1 × 10^15 cm^2 to 1 × 10^16 cm^2. We compared ZnO nanopillars solely implanted with Au-ions and dually-implanted with Au and Ag-ions. Rutherford Back-Scattering spectrometry (RBS) confirmed Ag and Au embedded in ZnO nanopillar layers in a reasonable agreement with theoretical calculations. A decreasing thickness of the ZnO nanopillar layer was evidenced with the increasing ion implantation fluences. Spectroscopic Ellipsometry (SE) showed a decrease of refractive index in the nanopillar parts with embedded Au, Ag-ions. XRD discovered vertical domain size decreasing with the proceeding radiation damage accumulated in ZnO nanopillars which effect was preferably ascribed to Au-ions. SE and diffuse reflectance spectroscopy (DRS) showed optical activity of the created nanoparticles at wavelength range 500 – 600 nm and 430 – 700 nm for the Au-implanted and Au, Ag-implanted ZnO nanopillars, respectively. Photoluminescence (PL) features linked to ZnO deep level emission appear substantially enhanced due to plasmonic interaction with metal nanoparticles created by Ag, Au-implantation.
Photocatalytic activity seems to be more influenced by the nanoparticles presented in the layer rather than the surface morphology. Dual implantation with Ag, Au-ions enhanced optical activity to a larger extent without significant morphology deterioration as compared to the solely Au-ion implanted nanopillars.
KW - ZnO nanopillars
KW - Au/Ag nanoparticles,
KW - Ion implantation
KW - SPR
KW - Doped ZnO nanostructures
PY - 2022
DO - https://doi.org/10.1016/j.apsusc.2022.155556
SN - 0169-4332
VL - 610
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-56306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sergievskaya, A.
A1 - Absil, R.
A1 - Chauvin, A.
A1 - Yusenko, Kirill
A1 - Vesely, J.
A1 - Godfroid, T.
A1 - Konsstantinidis, S.
T1 - Sputtering onto liquids: How does the liquid viscosity affect the formation of nanoparticles and metal films?
N2 - This paper reports on the effect of the solvent viscosity on the formation of gold nanoparticles (Au NPs) during Sputtering onto Liquid (SoL) process. All other parameters related to the plasma and the host liquid are kept constant. SoL is a simple highly reproducible approach for preparation of colloidal dispersions of small naked NPs. The properties of the final product are determined by both the sputtering parameters and the host liquid characteristics. As a model system we chose to sputter a gold target by a direct-current magnetron discharge onto a line of polymerized rapeseed oils having similar surface tension (32.6 ― 33.1 mJ·m-2 at RT). It was found that well dispersed Au NPs grow in the bulk solution of oils with low viscosities (below 630 cP at 25 °C) while gold films form onto the surface of high viscosity liquids (more than 1000 cP at 25 °C). The mean diameter of the individual Au NPs slightly increases with oil viscosity and is in range about 2.1―2.5 nm according to transmission electron microscopy.
KW - Liquid spattering
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.1039/D2CP03038A
SN - 1463-9084
VL - 25
IS - 4
SP - 2803
EP - 2809
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-56562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding
N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. Firstly, the local variation of the solidification sequence of the weld pool causes an increase in the hot-cracking susceptibility due to a locally delayed solidification. Secondly, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g. during the welding with filler materials, is blocked. This leads to a non-homogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results which were supported by selected experimental validation results.
T2 - International Congress of Applications of Lasers & Electro-Optics 2022
CY - Orlando, FL, USA
DA - 17.10.2022
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
KW - Porosity
KW - Numerical process simulation
PY - 2022
SP - 1
AN - OPUS4-56532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - VORSTELLUNG DES NEUEN GFKORR ARBEITSKREISES „ATMOSPHÄRISCHE KORROSION“
N2 - In diesem Vortrag wird ein Überblick über die Themen und Schwerpunkte des Arbeitskreises Atmosphärische Korrosion gegeben. Dabei werden einige Beispiele für relevante Fragestellungen aufgegriffen.
T2 - Sitzung des GfKORR AK Eisen und Stahl
CY - Online meeting
DA - 08.12.2022
KW - Korrosion
KW - Atmosphäre
KW - Luftqualität
KW - Auslagerungsversuche
PY - 2022
AN - OPUS4-56546
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Malakhov, A.
A1 - Epishin, A.
A1 - Denisov, I.
A1 - Saikov, I.
A1 - Nolze, Gert
T1 - Morphology and Structure of Brass–Invar Weld Interface after Explosive Welding
N2 - This paper presents the results of a study of the morphology and structure at the weld interface in a brass–Invar bimetal, which belongs to the class of so-called thermostatic bimetals, or thermobimetals. The structure of the brass–Invar weld interface was analyzed using optical microscopy and scanning electron microscopy (SEM), with the use of energy-dispersive X-ray (EDX) spectrometry and back-scattered electron diffraction (BSE) to identify the phases. The distribution of the crystallographic orientation of the grains at the weld interface was obtained using an e-Flash HR electron back-scatter diffraction (EBSD) detector and a forward-scatter detector (FSD). The results of the study indicated that the weld interface had the wavy structure typical of explosive welding. The wave crests and troughs showed the presence of melted zones consisting of a disordered Cu–Zn–Fe–Ni solid solution and undissolved Invar particles. The pattern quality map showed that the structure of brass and Invar after explosive welding consisted of grains that were strongly elongated towards the area of the highest intensive plastic flow. In addition, numerous deformation twins, dislocation accumulations and shear bands were observed. Thus, based on the results of this study, the mechanism of Cu–Zn–Fe–Ni structure formation can be proposed.
KW - Explosive welding
KW - Thermobimetal
KW - Grain structure
KW - Brass
KW - Invar
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565964
DO - https://doi.org/10.3390/ma15238587
SN - 1996-1944
VL - 15
IS - 23
SP - 1
EP - 10
PB - MDPI
AN - OPUS4-56596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Katrin
A1 - Schmitt Rahner, M.
A1 - Stolzenberg, U.
A1 - Kraft, Sebastian
A1 - Bonse, Jörn
A1 - Feist, C.
A1 - Albrecht, D.
A1 - Pullner, B.
A1 - Krüger, Jörg
T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing
N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2.
KW - Ultrashort pulsed laser
KW - X-ray emission
KW - X-ray spectrum
KW - X-ray energies
KW - Radiation protection
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176
DO - https://doi.org/10.3390/ma15248996
VL - 15
IS - 24
SP - 1
EP - 17
PB - MDPI
AN - OPUS4-56617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitalisierung in der Additiven Fertigung
N2 - Die Entwicklung einer digitalen QI ermöglicht die objektive Qualitätssicherung in der Additiven Fertigung und macht die Technologie gerade auch für kleine und mittelständische Unternehmen besser nutzbar. Sie wird vollwertig im Rahmen des Qualitätsanspruchs „Made in Germany“ einsetzbar – gerade auch beim Umbruch in Industriezweigen. Der Vortrag gibt Einblicke in aktuelle Arbeiten und die Ziele des Use Case Additive Fertigung.
T2 - LEF-Themenwoche, Bayerisches Laserzentrum
CY - Online meeting
DA - 21.03.2023
KW - Digitalisierung
KW - Qualitätsinfrastruktur
KW - Additive Fertigung
KW - Qualitätssicherung
PY - 2023
AN - OPUS4-57186
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Harsha, A. P.
A1 - Wäsche, Rolf
A1 - Joyce, T. J.
T1 - Friction and wear of two polyethylenes under different tribological contact conditions
N2 - Tribological properties of ultrahigh-molecular weight polyethylene (UHMWPE) and cross-linked polyethylene (XLPE) were studied in two different wear modes. Firstly, reciprocating sliding wear studies under non-conformal contact investigated the effects of counterface surface roughness (polished, lapped and ground) of Ti6Al4V on the friction and wear of the polyethylenes. Secondly, two-body abrasive wear studies in conformal contact against different abrasive grit size papers were also carried out to ascertain the wear sensitivity of the polyethylenes under these adverse conditions. Wear mechanisms were studied using optical and scanning electron micrographs. The results of the reciprocating sliding wear studies showed that surface roughness of the counterface influenced friction and wear characteristics although no correlation was found between the coefficient of friction and specific wear rate. XLPE demonstrated wear sensitivity, particularly under severe abrasive wear condition. The results indicated that the performance of the polyethylenes greatly depends upon the tribological system under which it is operating.
KW - Abrasive wear
KW - Polyethylene
KW - Reciprocating sliding wear
KW - Surface roughness
KW - Wear mechanism
PY - 2021
DO - https://doi.org/10.1177/0967391120920130
SN - 0967-3911
SN - 1478-2391
VL - 29
IS - 5
SP - 393
EP - 404
PB - Sage Publishing
CY - London
AN - OPUS4-56903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kinne, R. W.
A1 - Gunnella, F.
A1 - Kunisch, E.
A1 - Heinemann, S.
A1 - Nies, B.
A1 - Maenz, S.
A1 - Horbert, V.
A1 - Illerhaus, Bernhard
A1 - Huber, R.
A1 - Firkowska-Boden, I.
A1 - Bossert, J.
A1 - Jandt, K. D.
A1 - Sachse, A.
A1 - Bungartz, M.
A1 - Brinkmann, O.
T1 - Performance of calcium phosphate cements in the augmentation of sheep vertebrae - An ex vivo study
N2 - Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactideco-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2–4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5). Untouched (L1) and empty vertebrae (L2) served as controls. Cement performance was analyzed using micro-computed tomography, histology, and biomechanical testing. Extrusion was comparable for Paste-CPC(-PLGA) and PMMA, but significantly lower for CPC + PLGA. Compressive strength and Young’s modulus were similar for Paste-CPC and PMMA, but significantly higher compared to those for empty defects and/or CPC + PLGA. Expectedly, all experimental groups showed significantly or numerically lower compressive strength and Young’s modulus than those of untouched controls. Ready-to-use Paste-CPC demonstrates a performance similar to that of PMMA, but improved biomechanics compared to those of water-based CPC + PLGA, expanding the therapeutic arsenal for bone defects. O, significantly lower extrusion of CPC + PLGA fibers into adjacent lumbar spongiosa may help to reduce the risk of local extrusion in spinal surgery.
KW - Sheep
KW - PMMA
KW - Calcium phosphate bone cement
KW - Oil-based
KW - Ready-to-use
KW - Water-based
KW - Micro-CT
KW - Compressive strength
KW - Young’s modulus
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569072
DO - https://doi.org/10.3390/ma14143873
SN - 1996-1944
VL - 14
IS - 14
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-56907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Einführung Ultrakurzpulslaser
N2 - Der Vortrag gibt eine Einführung zu ultrakurzen Laserpulsen, der Ultrakurzpulslaser-Materialbearbeitung und dem Schutz gegenüber unerwünschter Röntgenstrahlung bei der Ultrakurzpulslaser-Materialbearbeitung.
T2 - Vorkommnisse in der Medizin und Ultrakurzpulslaser, Veranstaltungsreihe: Erfahrungsaustausch zu Themen des Vollzugs im Strahlenschutz
CY - Cologne, Germany
DA - 26.04.2023
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
KW - Abschirmung
PY - 2023
AN - OPUS4-57408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolar, Tomislav
A1 - Pearce, Ben K.D.
A1 - Etter, Martin
A1 - Truong, Khai-Nghi
A1 - Ostojić, Tea
A1 - Krajnc, Andraž
A1 - Mali, Gregor
A1 - Rossi, Barbara
A1 - Molčanov, Krešimir
A1 - Lončarić, Ivor
A1 - Meštrović, Ernest
A1 - Užarević, Krunoslav
A1 - Grisanti, Luca
T1 - Base-pairing of uracil and 2,6-diaminopurine: from cocrystals to photoreactivity
N2 - We show that the non-canonical nucleobase 2,6-diaminopurine (D) spontaneously base pairs with uracil (U) in water and the solid state without the need to be attached to the ribose-phosphate backbone. Depending on the reaction conditions, D and U assemble in thermodynamically stable hydrated and anhydrated D-U base-paired cocrystals. Under UV irradiation, an aqueous solution of D-U base-pair undergoes photochemical degradation, while a pure aqueous solution of U does not. Our simulations suggest that D may trigger the U photodimerization and show that complementary base-pairing modifies the photochemical properties of nucleobases, which might have implications for prebiotic chemistry.
KW - Mechanochemistry
KW - In situ monitoring
KW - Cocrystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608622
DO - https://doi.org/10.1016/j.isci.2024.109894
VL - 27
IS - 6
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-60862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Davison, Nathan
A1 - Hemingway, Jack M.
A1 - Wills, Corinne
A1 - Stolar, Tomislav
A1 - Waddell, Paul G.
A1 - Dixon, Casey M.
A1 - Barron, Luke
A1 - Dawson, James A.
A1 - Lu, Erli
T1 - Mechanochemical Synthesis of a Sodium Anion Complex [Na+(2,2,2-cryptand)Na–] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions
N2 - Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is −1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na+(2,2,2-cryptand)Na–], which allows us to unveil a versatile reactivity profile of this once exotic species.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608632
DO - https://doi.org/10.1021/acs.inorgchem.4c02914
VL - 63
IS - 32
SP - 15247
EP - 15258
PB - American Chemical Society (ACS)
AN - OPUS4-60863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giv, Ali Nemati
A1 - Asante, Bright
A1 - Yan, Libo
A1 - Kasal, Bohumil
T1 - Shear performance and durability of adhesively bonded spruce wood-concrete composite joints: Effects of indoor and outdoor environmental conditions, mechanical load, and their coupled effect
N2 - A long-term study was conducted on double-lap spruce wood-concrete joints to investigate their shear strength and stiffness over a 12-month period. These joints were manufactured using both wet and dry processes, each incorporating two adhesive types for bonding the wood to the concrete: a brittle epoxy and a ductile polyurethane (PUR). The experimental design exposed the joints to three specific long-term environments: (1) outdoor exposure, (2) indoor conditions with applied load, and (3) outdoor conditions with applied load. The wood concrete joints exposed to outdoor conditions were subjected to destructive shear testing at intervals of 0 (serving as the reference sample), 2, 4, 6, and 12 months, respectively. For joints subjected to both indoor and outdoor conditions with shear loading, the shear deformation of joints was monitored continuously over the 12 months before performing the destructive tests. A gradual reduction in the shear stiffness and strength of dry joints (produced using the dry bond method) exposed to outdoor conditions was observed over a 12-month period, primarily due to bond failure at the concrete-adhesive interface. The wet joints exhibited no degradation in shear stiffness and strength across long-term conditions over the same period. The bond failure observed in dry joints was predominantly associated with stresses arising from dimensional changes in the wood. No degradation was found in the cross-linking density of the adhesive or in the concrete’s compressive stiffness and strength.
KW - Adhesively bonded joints
KW - Long-term study
KW - Ductile PUR
KW - Brittle epoxy
KW - Outdoor condition
KW - Mechanical load
KW - Indoor condition
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608878
DO - https://doi.org/10.1016/j.conbuildmat.2024.136905
VL - 436
SP - 1
EP - 22
PB - Elsevier BV
AN - OPUS4-60887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemiasheuski, Anton
A1 - Kranzmann, Axel
A1 - Pfennig, Anja
T1 - Herausforderungen und Möglichkeiten des manuellen metallografischen Serienschnittverfahrens anhand einer quantitativen Gefügeanalyse der Grafite eines Gusseisens
T1 - Challenges and possibilities of the manual metallographic serial sectioning process using the example of a quantitative microstructural analysis of graphite in cast iron
N2 - Die in dieser Studie vorgestellte 3D-Gefüge-Analyse konzentriert sich auf die Kugelgrafite eines Gusseisens des Typs EN-GJS. Es werden die Form anhand des Formfaktors und des Seitenverhältnisses sowie die durchschnittliche Teilchengröße und -verteilung untersucht.
Die Form der Grafite in Gusseisenwerkstoffen ist mitentscheidend für die mechanischen Eigenschaften dieser Legierungen und ist bei der Charakterisierung des Werkstoffs unumgänglich. Mittels Metallografischen Serienschnittverfahrens wird von dem Schicht für Schicht abgetragenen und lichtmikroskopisch schichtweise dargestellten Werkstoff ein digitaler Zwilling erstellt. Von diesem dreidimensionalen Zwilling lassen sich beliebige Ebenen digital projizieren und analysieren. Eine konventionelle quantitative 3D-Analyse untersucht die Voxelmenge und -zusammensetzung eines Körpers im 3D-Raum. Die hier vorgestellte Analyse wendet stereologische 2D-Analyseverfahren auf drei Raumebenen des Werkstoffs an. Dabei sind zwei der Ebenen digitale Projektionen des Zwillings. Die zwei rekonstruierten Ebenen des Werkstoffs sind so gewählt, dass die Richtungsvektoren aller drei Ebenen einen 90°-Winkel zueinander bilden. Diese Methodik wird eingehend beschrieben sowie Herausforderungen und Möglichkeiten des hier vorgestellten Serienschnittverfahrens diskutiert.
N2 - The 3D microstructure analysis presented in this study focuses on the nodular graphite of an EN-GJS grade cast iron. The shape is analyzed based on shape factor and aspect ratio as well as average particle size and distribution. The shape of graphites in cast iron materials is critical to the mechanical properties of these alloys and is essential for the characterization of the material. Metallographic serial sectioning creates a digital twin of the material, which is removed layer by layer and visualized layer by layer under an optical microscope. From this three-dimensional twin, any number of planes can be digitally projected and analyzed. Conventional quantitative 3D analysis examines the voxel count and composition of a body in 3D space. The analysis presented here applies stereological 2D analysis methods to three spatial planes of the material. Two of the planes are digital projections of the twin. The two reconstructed planes of the material are chosen so that the direction vectors of all three planes form an angle of 90° to each other. The methodology is described in detail and the challenges and opportunities of the serial section method presented here are discussed.
KW - Dreidimensionale Gefügeanalyse
KW - Three-dimensional microstructure analysis
KW - 3D-Metallografie
KW - Serienschnittverfahren
KW - Gefügerekonstruktion
KW - Quantitative Gefügeanalyse
KW - 3D metallography
KW - Serial sectioning
KW - Microstructure reconstruction
KW - Quantitative microstructure analysis
PY - 2024
DO - https://doi.org/10.1515/pm-2024-0066
SN - 0032-678X
VL - 61
IS - 9-10
SP - 746
EP - 768
PB - De Gruyter
CY - Berlin/Boston
AN - OPUS4-60976
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
A1 - Hertwig, Andreas
A1 - Döhring, Thorsten
A1 - Stanik, Eva
A1 - Cotroneo, Vincenzo
A1 - Gibertini, Eugenio
T1 - Ellipsometrical characterization of poly-dopamine layers considered for technical applications
N2 - Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as the “hormone of happiness”, thin films of poly-dopamine also have interesting technical properties. When produced by dip coating, the self-organizing layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometer thickness only. In this work, we introduce a method of determining the layer thickness of poly-dopamine on mirrors for astronomical X-ray telescopes. This work is based on spectroscopic ellipsometry measurements and involves the development of an optical model for the poly-dopamine layers including the dielectric function. Thereby the complex refractive index of the produced layers was determined, covering the range from the ultraviolet to the near infrared spectral region. These measurement results and the corresponding technical challenges are presented in this contribution. Furthermore, an outlook to potential technical applications of this interesting material is given and poly-dopamine layers will make scientist and engineers hopefully happy as an innovative and fascinating technical solution for the future.
T2 - SPIE PHOTONICS EUROPE
CY - Strasbourg. France
DA - 08.04.2024
KW - Polydopamine
KW - Thin Solid Layers
KW - X-ray optics
KW - Spectroscopic Ellipsometry
PY - 2024
SN - 978-1-5106-7344-1
DO - https://doi.org/10.1117/12.3015281
VL - 13013
SP - 1
EP - 8
PB - SPIE digital library
AN - OPUS4-60954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Hildebrandt, N.
T1 - Near infrared quantum dots for biosensing and bioimaging
N2 - Quantum dots (QDs) possess unique optoelectronic properties, which make them very attractive to be used as optical probes in biosensing and bioimaging applications. The strong absorbance and light scattering of biological compounds like tissue and blood in the visible range pose a problem. However, if optical probes emitting in the near-infrared (NIR) range are used, scattering, absorption, and autofluorescence of biological components are strongly reduced. This allows for an increased light penetration depth and higher spatial and temporal resolution for the investigation of biological processes. The synthesis and application of NIR emitting QDs is a fast-growing research field and the benefits of using QDs were demonstrated for a variety of applications, such as photoelectrochemical biosensor, in vivo vascular imaging, and fluorescence-guided surgery. This article reviews the state-of-the-art developments in the preparation of NIR/IR QDs and highlights the latest research about their utilization in biosensing and bioimaging applications.
KW - Quantum dots
KW - Near-infrared
KW - Biosensing
KW - Bioimaging
KW - NIR-II / SWIR
KW - Advanced nanomaterials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609708
SN - 0165-9936
DO - https://doi.org/10.1016/j.trac.2024.117922
VL - 180
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-60970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diller, Johannes
A1 - Siebert, Ludwig
A1 - Winkler, Michael
A1 - Siebert, Dorina
A1 - Blankenhagen, Jakob
A1 - Wenzler, David
A1 - Radlbeck, Christina
A1 - Mensinger, Martin
T1 - An integrated approach for detecting and classifying pores and surface topology for fatigue assessment 316L manufactured by powder bed fusion of metals using a laser beam using μ$$ \mu $$CT and machine learning algorithms
N2 - AbstractThis research aims to detect and analyze critical internal and surface defects in metal components manufactured by powder bed fusion of metals using a laser beam (PBF‐LB/M). The aim is to assess their impact on the fatigue behavior. Therefore, a combination of methods, including image processing of micro‐computed tomography (CT) scans, fatigue testing, and machine learning, was applied. A workflow was established to contribute to the nondestructive assessment of component quality and mechanical properties. Additionally, this study illustrates the application of machine learning to address a classification problem, specifically the categorization of pores into gas pores and lack of fusion pores. Although it was shown that internal defects exhibited a reduced impact on fatigue behavior compared with surface defects, it was noted that surface defects exert a higher influence on fatigue behavior. A machine learning algorithm was developed to predict the fatigue life using surface defect features as input parameters.
KW - Fatigue
KW - Machine learning
KW - Micro-computed tomography
KW - Powder bed fusion of metals using a laser beam
KW - Quality assurance
PY - 2024
DO - https://doi.org/10.1111/ffe.14375
SN - 8756-758X
SP - 1
EP - 16
PB - John Wiley & Sons Ltd.
AN - OPUS4-60593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
T1 - Thermographic Investigation of the Anisotropic Behaviour of Additively Manufactured AISI 316 Steel using DED-arc
N2 - Additive manufacturing is one of the most promising techniques for industrial production and maintenance, but the specifics of the layered structure must be considered. The Direct Energy Deposition-Arc process enables relatively high deposition rates, which is favourable for larger components. For this study, specimens with different orientations were prepared from one AISI316 steel block – parallel and orthogonal to the deposition plane. Quasistatic tensile loading tests were carried out, monitored by an infrared camera. The obtained surface temperature maps revealed structural differences between both orientations. The consideration of surface temperature transients yields more details about the behaviour of the material under tensile loading than the conventional stress-strain-curve. These preliminary investigations were supplemented by thermographic fatigue trials. Although the anisotropy was also observed during fatigue loading the fatigue behaviour in general was the same, at least for both inspected specimens. The presented results demonstrate the abilities and the potential of thermographic techniques for tensile tests.
T2 - 17th Quantitative Infrared Thermography Conference
CY - Zagreb, Croatia
DA - 01.07.2024
KW - Thermoelastic effect
KW - Thermoplastic effect
KW - Thermal stress analysis
PY - 2024
AN - OPUS4-60574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bacurau, V. P.
A1 - Moreira, P. A. F. P.
A1 - Bertoli, G.
A1 - Andreoli, A. F.
A1 - Mazzer, E.
A1 - de Assis, F. F.
A1 - Gargarella, P.
A1 - Koga, G.
A1 - Stumpf, G. C.
A1 - Figueroa, S. J. A.
A1 - Widom, M.
A1 - Kaufman, M.
A1 - Fantin, Andrea
A1 - Cao, Y.
A1 - Freitas, R.
A1 - Miracle, D.
A1 - Coury, F. G.
T1 - Comprehensive analysis of ordering in CoCrNi and CrNi2 alloys
N2 - Chemical Short-Range Order (CSRO) has attracted recent attention from many researchers, creating intense debates about its impact on material properties.
The challenges lie in confirming and quantifying CSRO, as its detection proves exceptionally demanding, contributing to conflicting data in the literature regarding its true effects on mechanical properties. Our work uses highprecision calorimetric data to unambiguously prove the existence and, coupled with atomistic simulations, quantify the type of CSRO. This methodology allows us to propose a mechanism for its formation and destruction based on the heat evolution during thermal analysis and facilitates a precise identification of local ordering in CoCrNi alloys. Samples of CoCrNi (Co33Cr33Ni33) and CrNi2 (Cr33Ni66) alloys are fabricated in varying ordered states, extensively characterized via synchrotron X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy. Samples with considerably different ordered states are submitted to tensile tests with in-situ synchrotron X-ray diffraction. We demonstrate, despite inducing varied CSRO levels in CoCrNi, no significant alterations in overall mechanical behavior emerge.
However, the CrNi2 alloy, which undergoes long-range ordering, experiences significant shifts in yield strength, ultimate tensile stress and ductility.
KW - Mechanical properties
KW - Short-range ordering
KW - Calorimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611075
DO - https://doi.org/10.1038/s41467-024-52018-w
VL - 15
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alić, Jasna
A1 - Schlegel, Moritz-Caspar
A1 - Emmerling, Franziska
A1 - Stolar, Tomislav
T1 - Meeting the UN Sustainable Development Goals with Mechanochemistry
N2 - Chemistry traditionally relies on reactions in solution, but this method is increasingly problematic due to the scale of chemical processes and their economic and environmental impact. Handling residual chemical waste, including solvents, incurs significant costs and environmental pressure. Conversely, novel chemical approaches are needed to address pressing societal issues such as climate change, energy scarcity, food insecurity, and waste pollution. Mechanochemistry, a sustainable chemistry discipline that uses mechanical action to induce chemical reactivity without bulk solvents, is a hot topic in academic research on sustainable and green chemistry. Given its fundamentally different working principles from solution chemistry, mechanochemistry offers more efficient chemical processes and the opportunity to design new chemical reactions. Mechanochemistry has a profound impact on many urgent issues facing our society and it is now necessary to use mechanochemistry to address them. This Minireview aims to provide a guide for using mechanochemistry to meet the United Nations (UN) Sustainable Development Goals (SDGs), thereby contributing to a prosperous society. Detailed analysis shows that mechanochemistry connects with most UN SDGs and offers more cost‐efficiency than other approaches together with a superior environmental performance.
KW - Mechanochemistry
KW - SDGs
PY - 2024
DO - https://doi.org/10.1002/anie.202414745
SP - 1
EP - 3
PB - Wiley
AN - OPUS4-61108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitale Qualitätssicherung in der Additiven Fertigung und Voraussetzungen in der Qualitätsinfrastruktur
N2 - Der Vortrag gibt einen Überblick über die Aktivitäten im QI-Digital Use Case Additive Fertigung, den aktuellen Stand und nächste Schritte.
Es wurde eine digitale Prozesskette für den PBF-LB/M Prozess aufgebaut. Hier werden Daten entlang der gesamten Fertigungsstrecke gesammelt, ausgewertet und zur Qualitätssicherung weiterverarbeitet. Die grundlegende Datenstruktur wurde in die Normung überführt.
T2 - TÜV SÜD Fachtagung: Additive Fertigung von Druckgeräten
CY - Munich, Germany
DA - 17.09.2024
KW - Digitalisierung
KW - Qualitätsinfrastruktur
KW - Additive Fertigung
PY - 2024
AN - OPUS4-61089
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tang, Chi-Long
T1 - UFP-Emission beim 3D-Druck
N2 - Desktop-3D-Drucker haben in der letzten Dekade große Popularität in Bildungseinrichtungen, kleinen Unternehmen und Privathaushalten erlangt. Weit verbreitet ist mittlerweile die „Fused Filament Fabrication (FFF)“ Technologie. Hier wird ein thermoplastisches Filament geschmolzen, durch eine Metalldüse extrudiert und anschließend schichtweise so auf ein Druckbett aufgetragen, dass ein 3D-Objekt entsteht. Das Filamentmaterial wird dabei thermisch stark belastet, was zur Emission von Aerosolen sowie flüchtigen organischen Verbindungen (VOC) führt. Dabei werden hauptsächlich ultrafeine Partikel (UFP, dP < 100 nm) freigesetzt werden, die sogar in manchen Fällen im sub-4nm Größenbereich einen signifikanten Anteil ausmachen können (Tang und Seeger 2024).
Die gesundheitliche Relevanz eingeatmeter UFP ist durch sehr viele Studien gut belegt. Während eines i.d.R. mehrstündigen FFF-Druckvorgangs wird ein Anwender mit diesen Luftschadstoffen im Innenraum exponiert, häufig ohne eine Einschätzung des damit verbundenen Risikos zu haben. Die Exposition kann durch technische Faktoren (z.B. Druckerausstattung und -einstellung, Innenraumventilation), aber auch erheblich durch die Filamentauswahl beeinflusst werden. Unser Vorschlag zur Risikominderung besteht in der Auszeichnung emissionsarmer Filamentprodukte mit dem Umweltzeichen „Blauer Engel“, um so den Verbrauchern eine fundierte Auswahl zu ermöglichen. In unserem Projekt entwickeln wir dafür ein kammerbasiertes, standardisierbares und robustes Prüfverfahren zur vergleichenden Messung der Emission aus Filamenten. Mit dem Strangdruck-Verfahren (engl. Strand Printing Method, SPM) wird eine festgelegte Filamentlänge mit konstanter Rate extrudiert und auf dem Druckbett abgelegt, ohne dabei ein 3D-Objekt aufzubauen. Diese Vorgehensweise reduziert den Einfluss experimentell schlecht zu kontrollierender Faktoren sowie die Ausfallquote. Eine detaillierte Beschreibung und die Vorteile von SPM werden in Tang und Seeger (2022) erläutert. SPM wurde bereits für 44 Filamentprodukte aus unterschiedlichen Polymeren und Additiven als Vergleichstest angewendet. Alle Messungen wurden in einer klimatisierten 1 m³-Emissionsprüfkammer durchgeführt. Die Gesamtanzahl der emittierten Partikel (TP) dient als Beurteilungsmaß, in Anlehnung an die Vergabegrundlage DE-UZ-219 des Umweltzeichens Blauer Engel für Laserdrucker. Unter den getesteten Filamentprodukten variiert TP um ca. vier Größenordnungen (1E+9 ≤ TP ≤ 1E+13). Auch innerhalb jeder der untersuchten Polymergruppen variierte TP signifikant. Die Partikelemission kann daher nicht allein nach dem Basispolymer kategorisiert werden. Unsere Resultate belegen, dass die Stärke der Partikelemission eher eine charakteristische und individuelle Eigenschaft eines Filamentproduktes ist. Die Herkunft der Polymere, die herstellerspezifischen Additive sowie die nicht deklarierte Verunreinigungen können einen starken Einfluss auf die Emission haben. Die Auszeichnung von emissionsarmen Filament-produkten verspricht somit eine einfache, aber effektive Maßnahme zu sein, um Verbrauchern eine Minderung des Expositionsrisikos beim FFF-3D-Druck zu ermöglichen.
T2 - 5. Symposium "Ultrafeinstaub in der Atmosphäre und in Innenräumen"
CY - Berlin, Germany
DA - 16.09.2024
KW - 3D-Druck
KW - Ultrafeine Partikel
KW - Innenraumemission
KW - Luftschadstoffe
KW - Emissionsprüfung
PY - 2024
AN - OPUS4-61067
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gaddam, Anuraag
A1 - Galleani, Gustavo
A1 - de Lima Reis, Vitor
A1 - de Camargo, Andrea S. S.
A1 - Eckert, Hellmut
T1 - Structural characterization of gallium fluoride phosphate glasses by advanced solid‐state NMR methods and correlation with photophysical properties
N2 - AbstractGallium fluoride phosphate glasses feature low refractive index, high energy radiation resistance, wide transmission range, and favorable emission characteristics of rare‐earth dopants. For the development of optimized glass compositions, a fundamental understanding of these properties in terms of glass structure is sought. We report nuclear magnetic resonance (NMR) structural studies of glasses in the system xGa(PO3)3–(40 − x)GaF3–20BaF2–20ZnF2–20SrF2 (x = 5, 10, 15, 20, and 25 mol%). 31P NMR results with 71Ga recoupling show that the network structure is dominated by P–O–Ga linkages, and no P–O–P linkages exist. 71Ga NMR results show that Ga is mainly six‐coordinated featuring a mixed fluoride/phosphate coordination. Quantitative estimates of this ligand distribution around gallium were obtained by 71Ga{31P} spin echo double resonance (REDOR) measurements. Photophysical properties suggest changes in the Eu(III) ligand distribution toward a fluoride‐dominated environment at low P/F ratio while the glass network is largely sustained by bridging oxygen atoms via P–O–Ga linkages.
KW - Gallium
KW - Glass
KW - NMR
KW - Oxyfluoride
PY - 2024
DO - https://doi.org/10.1111/jace.20051
SN - 0002-7820
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-60785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merízio, Leonnam Gotardo
A1 - Machado, Ian Pompermayer
A1 - Vastamäki, Roosa
A1 - de Camargo, Andréa Simone Stucchi
A1 - Lastusaari, Mika
T1 - Multifunctional persistent luminescent and photochromic hackmanite-based materials prepared by microwave-assisted solid-state synthesis
N2 - Advanced optical materials inspired by natural minerals and non-toxic light elements, such as the Hackmanites (Na8Al6Si6O24(Cl,S)2), find vast possibilities of applications as they can simultaneously perform photochromism and persistent luminescence (PersL). In this work, we have explored a rapid and energy-efficient microwaveassisted (MASS) methodology for the synthesis of PersL and photochromic hackmanites. In addition, we have prepared hackmanite materials using a zeolite-free precursor to control the Na–Al–Si ratio and study its influence on the materials photoluminescent properties. The PersL hackmanites showed a white-bluish emission color, with up to 2 h of emission time. Zeolite-free photochromic materials were able to change the color from white to purple/blue efficiently with a few seconds of 254 nm excitation, but the usage of zeolite precursors enhanced the overall optical performance. Microwave synthesis times of 10–40 min were demonstrated to be optimal, as longer times boosted the formation of nepheline spurious phase, which decreases luminescence efficiency. In this way, the MASS method led to a reduction of reaction time up to 98 %, yielding hackmanite materials with similar photoluminescent or photochromic properties compared to those obtained by a 24 h conventional solid-state synthesis. This work represents a significant improvement toward coupling eco-friendly synthetic processes to
eco-friendly solid-state materials for PersL illumination and PersL/photochromism optical marking.
KW - Hackmanite
KW - Persistent luminescence
KW - Photochromism
KW - Microwave-assisted synthesis
PY - 2024
DO - https://doi.org/10.1016/j.optmat.2024.115826
SN - 0925-3467
VL - 155
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Transitions from scale-free to scale-dependent fluctuations in plasticity
N2 - Plastic deformation in crystals is mediated by the motion of line defects known as dislocations. For decades, dislocation activity has been treated as a homogeneous, smooth continuous process that relies on well-average quantities. However, it is now recognized that plasticity can be determined by long-range correlated and intermittent collective dislocation activity, known as avalanches. These abrupt plastic fluctuations often exhibit pure power-law scaling or truncated power-law scaling, which indicates at least some degree of scale-free dislocation behavior. Intriguingly, such statistical signatures can persist across scales exceeding those of the material’s microstructure, raising the question of what relationship there may be between structure and long-range correlated dislocation activity that underlie power-law scaling.
In this talk, we address this question by highlighting examples in which a transition from scale-free to scale-dependent plastic deformation is observed either due to changing external testing conditions (stress-state or temperature) or by tuning the microstructure. In particular, we will focus on the details of the temperature-driven change, that demonstrates how scale-free intermittent flow in body-centered cubic Nb is progressively quenched out with decreasing temperature. The plastic response of Nb is shown to be bimodal across the studied temperature regime, with conventional thermally-activated smooth plastic flow coexisting with sporadic bursts controlled by athermal screw dislocation activity, thereby violating the classical notion of temperature-dependent screw dislocation motion at low temperatures. An abrupt increase of the athermal avalanche component is identified at the critical temperature of the material. We combine the experimental observations with 3D dislocation dynamics simulations, identify a possible origin to athermal screw activity, and discuss the co-existence scale-free and scale-dependent plasticity.
T2 - Cairo Symposium on The Physics of Metal Plasticity
CY - Cairo, Egypt
DA - 05.09.2023
KW - Plastic deformation
KW - Dislocations
KW - Avalanches
PY - 2023
AN - OPUS4-60648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Glauer, M.
A1 - Schilling, Markus
A1 - Stappel, M.
T1 - A practical ontology development guide
N2 - Knowledge representation is becoming increasingly important in view of the large amounts of data that are handled in the modern scientific landscape. Many of the domains that have most readily realised this problem and worked on potential solutions have been the domain of biochemistry. And although the developments sought here were not accompanied by philosophers, this process organically led to the development of formal and structured representations of certain domains. While the resulting structures were not the first formal ontologies, they are ones that are still in wide use to this day. These approaches have led to major advances in the organisation, structuring and communication of scientific results. Since then, a variety of other domains have tried to adapt a similar process and develop their own ontologies. However, the development of ontologies from the domain of biochemistry was the result of a years-long process that also involved a large number of errors and course corrections. One of the greatest challenges is also one of the greatest strengths of ontologies: Interoperability with other ontologies. To ensure this interoperability, ontologies must follow certain principles. In the field of biochemistry, the OBO Foundry has established itself, which offers functionalities for a rich network of ontologies from the domain, but at the same time also defines rules.
The purpose of this document is to define a similar set of rules for open ontology development, but which addresses a broader domain and at the same time lowers the barrier of entry for new ontology developers. To this end, we will outline a workflow that can be used to build new ontologies more efficiently. This workflow is based not only on our own years of experience in ontology development, but also on the rules of external experts such as the OBO Foundry.
KW - Ontology
KW - Data integration
KW - Ontologie
KW - Data interoperability
PY - 2024
UR - https://scientific-ontology-network.github.io/
UR - https://github.com/scientific-ontology-network/ontology-development-guide/releases/download/v0.1.0/ontology-guide.pdf
SP - 1
EP - 27
PB - GitHub
CY - San Francisco
ET - Version 0.1
AN - OPUS4-61140
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Birkholz, Henk
A1 - Bayerlein, Bernd
T1 - Evolution of the PMD Core Ontology (PMDco) Towards ISO/IEC 21838-2:2021 Basic Formal Ontology (BFO)
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
In this presentation, an approach how to maintain a comprehensive and intuitive MSE-centric terminology composing a mid-level ontology–the PMD Core Ontology (PMDco)–via MSE community-based curation procedures is shown.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - MSE Congress 2024 - Materials Science and Engineering
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Ontology
KW - Semantic Interoperability
KW - Knowledge representation
KW - FAIR Data Management
KW - PMD Core Ontology
PY - 2024
AN - OPUS4-61141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eisenbart, Miriam
T1 - Digitalization of a high-throughput alloy development process
N2 - Digitalization is nowadays the central key in developing pharmaceutical products, but it also becomes increasingly important in computer aided material development. In this work it is presented how a collaborative ontology development for the alloy development process is approached and a workflow for chemical optimization of copper alloys is introduced. This is done by employing a combination of a high-throughput alloy development method [1] with the calculation of the corresponding phase compositions.
The work presented here is part of the publicly funded project KupferDigital. The project is associated with the innovation platform MaterialDigital (PMD) and focusses on the digitalization of processes as well as knowledge representation along the life-cycle of copper and copper alloys. One part of this life cycle is the alloy development of copper alloys, in this case the alloy development employing a high throughput method based on diffusion couples. The alloy development process can be further broken down into several typical material processing steps such as casting, diffusion welding and annealing. As part of the copper life cycle, the constitution and the properties of an alloy play an important role for processes further down the road during product manufacturing and service life and are also crucial for the recycling properties of the alloy. It is therefore important to, on the one hand, communicate data concerning properties, process history and constitution to the following stations of the life cycle, on the other hand, it is also elementary for the material scientist to be aware of the recycling properties of the alloys constituents. This motivates sharing of data along the life cycle and the development of ontology based data spaces, where life-cycle information can be linked across all involved domains.
As part of the alloy development process, it is presented how experimental data created at fem are shared using linked data and ontologies with an example based on the digital representation of the chemical composition of copper alloys further processed by CALculation of PHAse Diagrams (CALPHAD) at the Fraunhofer IWM. The calculation results are used to correlate measured hardness data with the equilibrium phases of the alloys. Selected Compositions are cast and heat treated and subjected to mechanical testing at BAM and the resulting mechanical property-data are again linked to the measured and simulated data from the alloy development process.
T2 - MSE2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Digitalization
KW - Alloy development
PY - 2024
AN - OPUS4-61150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Additive Fertigungsverfahren und Defekte
N2 - Überblick über die derzeitig wichtigsten additiven Fertigungsverfahren für metallische Werkstoffe in der Industrie (PBF, DED, BJT) und Berücksichtigung der wesentlichen Prozessmerkmale und Nachbearbeitungsschritte. Vorstellung der wichtigsten Defektphänomene und Nennung von Ursachen und Abhilfemaßnahmen.
T2 - BAM Akademie: Qualitätssicherung in der additiven Fertigung
CY - Online meeting
DA - 17.09.2024
KW - Additive Fertigung
KW - Defekte
KW - Überblick
PY - 2024
AN - OPUS4-61172
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schob, Daniela
T1 - Deformation-Induced Martensitic Transformation in Fused Filament Fabricated Austenitic Stainless Steels During Tension at Wide Range of Temperatures. Part 2: Numerical Simulation
N2 - Structural components of superconducting magnets (e.g., collars, bladders, or keys) with complex shapes, operating at cryogenic temperatures (4K, 77K), as well as additional elements of tanks for storing liquid hydrogen (20K), such as hoses and valves, are made of austenitic steel. With conventional manufacturing technologies, complex geometries are difficult to manufacture. In contrast, additive manufacturing offers the possibility of easier production of complex geometries, although the knowledge about the material behavior is not yet comprehensively available. The scientific objective of the project is the experimental identification and numerical simulation of the evolution of the deformation-induced martensitic transformation and the prediction of the material behavior of Fused Filemant Fabricated (FFF) 316L for cryogenic applications.
The material behavior of FFF-316L under tensile stress at both room temperature and 77K was characterized. Utilizing experimental data and microstructure analysis through scanning electron microscopy, a comprehensive material model [1] was used. This constitutive model is centered on the deformation-induced martensitic transformation at both ambient and cryogenic temperatures. The linear kinetic law of evolution of deformation-induced phase transformation in ASS is adopted [1]. It posits that the phase transformation is driven by the accumulated plastic strain. The model intricately links the intensity of plastic deformation to the phase transformation, employing a mixed kinematic/isotropic linear plastic hardening approach based on Mori-Tanaka homogenization. A numerical results will be verified experimentaly at room and at 77K.
T2 - 43rd Solid Mechanics Conference
CY - Wroclaw, Poland
DA - 16.09.2024
KW - Phase transformation
KW - Deformation-induced martensitic transformation
KW - 316L
KW - Fused Deposition Modelling
PY - 2024
AN - OPUS4-61181
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hohendorf, Stefan
T1 - Medea und Jason, Eine Radiologische Untersuchung im Neuen Palais Potsdam
N2 - Seit der Antike gehört die Medea-Sage zu den bekanntesten Geschichten der Weltliteratur. Der berühmte französische Künstler Carle Van Loo hat sich dieses Epos um 1759 angenommen und ein beeindruckendes Ölgemälde mit Abmessungen von 2,30x3,28m² erschaffen. Mit Mademoiselle Clairon als Medea und Henri Louis Le Kain als Jason ist ein Kunstwerk entstanden, das seitdem einige Veränderungen und Restaurierungen erfahren hat.
Die Bundesanstalt für Materialforschung und -prüfung (BAM) hatte 2020 die Möglichkeit, dieses und ein zweites Kunstwerk, im Neuen Palais in Potsdam, für die Stiftung Preußische Schlösser und Gärten Berlin-Brandenburg, radiografisch zu untersuchen. Hierbei wurden sowohl technologisch als auch kunsthistorisch einige interessante Entdeckungen gemacht, die im vorliegenden Beitrag vorgestellt werden.
T2 - DGZfP Jahrestatung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Röntgen
KW - X-Ray
KW - Kunsstechnologisch
KW - Gemälde
KW - Untermalung
KW - Speicherfolie
KW - Strahlenschutz
PY - 2022
AN - OPUS4-56577
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
A1 - Madia, Mauro
A1 - Schurig, M.
A1 - Schlums, H.
A1 - Zerbst, Uwe
T1 - Fracture mechanics-based structural integrity assessment of aeroengine turbine disks under overspeed conditions
N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on productionsimilar disks. While these tests provide, on the one hand, a reliable definition of the critical conditions for real components, on the other hand they represent a relevant cost item for engine manufacturers. The aim of this work is to present part of a fracture mechanics-based procedure under development which aims at replacing the tests on production-similar disks with lab tests on fracture mechanics specimens. In particular, the rimpeeling failure mode is considered as case study. A semi-circular surface crack is modelled at the most stressed region at the diaphragm of a turbine disk, with the crack plane perpendicular to the radial direction. The crack is therefore subjected to a biaxial stress state and grows under increasing rotational speed until it triggers the rim-peeling failure. The finite element simulation of the cracked disk considers the real thermal and mechanical loading conditions. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of � -integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. This has been achieved and as expected, both the highest � -integral and constraint factor are calculated at the same location along the crack front for both disk and specimen. The results of the structural integrity assessment in the form of a Failure Assessment Diagram (FAD) show good agreement between designed specimen and disk both in terms of expected failure mode and value of the critical speed. Probabilistic aspects are also considered in the calculations.
T2 - ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition (GT2022)
CY - Rotterdam, The Netherlands
DA - 13.06.2022
KW - Fracture mechanics
KW - Burst
KW - Turbine disk
PY - 2022
SP - 1
EP - 7
PB - ASME
AN - OPUS4-55903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sechi, R.
A1 - Fackeldey, K.
A1 - Chewle, Surahit
A1 - Weber, M.
T1 - SepFree NMF: A toolbox for analyzing the kinetics of sequential spectroscopic data
N2 - This work addresses the problem of determining the number of components from sequential spectroscopic data analyzed by non-negative matrix factorization without separability assumption (SepFree NMF). These data are stored in a matrix M of dimension “measured times” versus “measured wavenumbers” and can be decomposed to obtain the spectral fingerprints of the states and their evolution over time. SepFree NMF assumes a memoryless (Markovian) process to underline the dynamics and decomposes M so that M = WH, with W representing the components’ fingerprints and H their kinetics. However, the rank of this decomposition (i.e., the number of physical states in the process) has to be guessed from pre-existing knowledge on the observed process. We propose a measure for determining the number of components with the computation of the minimal memory effect resulting from the decomposition; by quantifying how much the obtained factorization is deviating from the Markovian property, we are able to score factorizations of a different number of components. In this way, we estimate the number of different entities which contribute to the observed system, and we can extract kinetic information without knowing the characteristic spectra of the single components. This manuscript provides the mathematical background as well as an analysis of computer generated and experimental sequentially measured Raman spectra.
KW - Kinetics from experiments
KW - Separability assumption
KW - Sequential spectroscopic data
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559046
DO - https://doi.org/10.3390/a15090297
SN - 1999-4893
VL - 15
IS - 9
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Eine digital gestützte Qualitätssicherung für die additive Fertigung
N2 - Die Digitalisierung der Qualitätsinfrastruktur (QI) am Beispiel der Additiven Fertigung.
Der Vortrag erörtert, wie die Elemente einer digitalen QI zur Qualitätssicherung und Zertifizierung in der Additiven Fertigung beitragen können.
T2 - Treffen der Arbeitsgemeinschaft Additive Fertigung des VDMA
CY - Coburg, Germany
DA - 27.10.2022
KW - Qualitätsinfrastruktur
KW - Additive Fertigung
KW - Digitalisierung
PY - 2022
AN - OPUS4-56165
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Höhne, Patrick
T1 - Optimized spray granules for dry pressing by means of slurry destabilization and ultrasonic atomization
N2 - The homogeneous introduction of organic additives is a prerequisite for good processability of ceramic powders during dry pressing. The addition of organic additives by wet route via ceramic slurries offers advantages over dry processing. The organic content can be reduced and a more homogeneous distribution of the additives on the particle surface is achieved. In addition to the measurements of zeta potential and viscosity, sedimentation analysis by optical centrifugation was also tested and successfully used to characterize the ceramic slurries and accurately evaluate of the suitability of different types, amounts, and compositions of organic additives.
Spray drying of well-stabilized slurries usually results in mostly hollow granules with a hard shell leading to sintered bodies with defects and reduced strength and density. By purposefully degrading the slurry stability after dispersion of the ceramic powder, the drying behavior of the granules in the spray drying process and thus the granule properties can be influenced. Destabilization of the slurry and thus partial flocculation was quantified by optical centrifugation. Spray drying of the destabilized alumina slurries resulted in "non-hollow" granules without the detrimental hard shell and thus improved granule properties.
Further improvement of the granules was achieved by installing ultrasonic atomization in the spray dryer. A narrower granule size distribution was achieved, which had a positive effect on, among other things, the flowability of the granules.
Specimens produced from this granules had fewer defects of smaller size, leading to better results for the density and strength of the sintered bodies. The observations made for alumina could be transferred to zirconia and as well to ZTA with 20 wt% zirconia.
T2 - Ceramics in Europe 2022
CY - Krakau, Poland
DA - 10.07.2022
KW - Ultrasound
KW - Spray drying
KW - Slurry
PY - 2022
AN - OPUS4-56171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
A1 - Klinger, Christian
T1 - Schadensanalyse an Fahrradkomponenten - Fraktographie, Ursachen, Prävention
N2 - Komponenten von Fahrrädern werden im Betrieb vorwiegend schwingend beansprucht. Typische Werkstoffe sind Stahl, Aluminiumlegierungen, Messing, CFK und thermoplastische Kunststoffe. Da es sich, unabhängig von der Preiskategorie, um konstruktiven Leichtbau handelt, werden einige Bauteile betriebsfest mehr oder weniger weit oberhalb der Dauerfestigkeit ausgelegt. Die im normalen Betrieb auftretenden Schäden sind daher weit überwiegend Schwingbrüche. Andere Schadensmechanismen wie z.B. Korrosion spielen quantitativ eine untergeordnete Rolle. Schwingbrüche treten nach einer Periode unbemerkten Risswachstums oft ohne Vorwarnung und ohne makroskopische Verformung auf. Im Falle von sicherheitsrelevanten Komponenten wie Rahmen, Gabeln, Lenkern, Sattelstützen, Kurbelarmen oder Pedalen kann dies zu erheblichen Personenschäden führen, die den Wert des ursächlichen Bauteilschadens weit überschreiten.
Über einen langjährigen Zeitraum wurden gebrochene Komponenten aus dem Alltag und aus Gerichtsverfahren analysiert. Das Hauptaugenmerk lag hierbei auf der fraktographischen Analyse, teilweise wurden die zu Grunde liegenden Schadensursachen ermittelt. Einflussfaktoren sind beispielsweise konstruktive Kerben an ungünstigen Stellen, aber auch Werkstoffwahl und Fertigungsqualität spielen eine Rolle. In den meisten Fällen wurde jedoch die konstruktive Lebensdauer überschritten. Diese wird praktisch nie mitgeteilt, und eine wiederkehrende Prüfung sicherheitsrelevanter Bauteile findet nicht statt.
Im Sinne der Vermeidung von Schäden und Unfällen könnte darauf hingewirkt werden, für sicherheitsrelevante Komponenten Lebensdauern besser abzuschätzen und von der Laufleistung abhängige Sichtprüfungen zu empfehlen.
T2 - DGM Tagung Werkstoffprüfung
CY - Dresden, Germany
DA - 26.10.2022
KW - Fraktographie
KW - Fahrrad
KW - Lebensdauer
KW - Öffentliche Sicherheit
KW - Schadensanalyse
KW - Schadensprävention
PY - 2022
AN - OPUS4-56122
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, T.
T1 - Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing
N2 - In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray.
T2 - ITSC 2022
CY - Vienna, Austria
DA - 04.05.2022
KW - Cold Spray
KW - Copper powder particles
KW - Electrical conductivity
KW - Large electrical high-voltage machine
PY - 2022
AN - OPUS4-56127
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, T.
A1 - Uhlmann, E.
A1 - Häcker, Ralf
A1 - Jäger, M.
A1 - Rauch, H.
A1 - Kondas, J.
A1 - Brach, K.
A1 - Singh, R.
T1 - Evaluation of electric conductivity and mechanical load capacity of copper deposits for application in large winding components for electrical high-voltage machines made with cold spray additive manufacturing
N2 - In line with the industrial trend of additive manufacturing, cold spray as a non-laser-based process is becoming increasingly important for many fields of application. For the evaluation of additive manufacturing of winding components made of copper for large electrical high-voltage machines, material and component properties such as electrical conductivity, mechanical load capacity and the component size that can be produced are of particular importance. In this context, the cold spray process offers advantages over laser-based additive manufacturing processes such as laser powder bed fusion (LPBF) or laser cladding by using the kinetic energy of the copper powder particles to generate particle cohesion. To investigate the electrical conductivity as well as the mechanical load capacity of cold spray parts, specimens were machined out of cold sprayed bulk copper deposits. The characteristic values were obtained with regard to the direction of deposition, which is defined by the direction of the robot’s movement. Thus, for the investigation of the component properties, specimens were provided that had been produced both longitudinally and transversely as well as orthogonally to the direction of deposition. The results of the investigations show that both the electrical conductivity and the mechanical load capacity of the specimen have a strong preferential direction of the specimen orientation with respect to the direction of deposition. Furthermore, it could be shown that by increasing the deposition height, there is an increasing oxygen content in the sample material, combined with increasingly significant defect networks. These effects have a negative impact on the electrical conductivity as well as on the mechanical load capacity. As a conclusion, further need for investigation is identified in the optimization of the process parameters as well as in the deposition strategy for the additive manufacturing of large-volume components with cold spray.
T2 - ITSC 2022
CY - Wien, Austria
DA - 04.05.2022
KW - Cold Spray
KW - Electrical conductivity
KW - Copper powder particles
KW - Large electrical high-voltage machine
PY - 2022
SP - 1
EP - 7
AN - OPUS4-56108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pialat, A.
A1 - Kitos, A.
A1 - Witkowski, Tomasz
A1 - Cook, C.
A1 - Wang, S.
A1 - Hu, A.
A1 - Murugesu, M.
T1 - Achieving short ignition delay and high specific impulse with cyanoborohydride based hypergolic ionic liquids
N2 - The efficient design of hypergolic-ionic-liquid (HIL) fuels with attractive features, (e.g., short ignition delay and high specific impulse) can be achieved by fine-tuning the molecular organization comprising both cations with appropriate alkyl chains and cyanoborohydride-based hydrogen-rich anions. Attractive features of the presented derivatives were attained by combining cations with various substituents (substituted 1H-1,2,4-triazol-4-ium, pyrrolidinium, ammonium and pyridinium cations) and the cyanoborohydride anion. All shown HILs display high thermal stabilities with thermal decomposition temperatures over 154 °C and possess higher densities (from 0.82 to 1.02 g cm−3) compared to the unsymmetrical dimethylhydrazine (UDMH, 0.793 g cm−3). The hypergolic ignition behavior of the propellant combination was evaluated by a drop test setup using white fuming nitric acid (WFNA) as an oxidizer and recorded using a high-speed camera. All compounds feature ignition delay times (ID) under 50 ms, while the 1-hexyl-1-methylpyrrolidin-1-ium cyanotrihydroborate congener (17) exhibited the shortest ID time (5 ms), which is comparable to the ID time of UDMH (4.8 ms with WFNA as an oxidizer). In addition, these HILs exhibit higher heats of formation (187.6 to 392.6 kJ mol−1), heats of combustion (34.39 to 47.15 kJ g−1) and specific impulse (176 to 205 s) compared to UDMH.
KW - Hypergolic ionic liquids
PY - 2022
DO - https://doi.org/10.1039/D2NJ03372K
SN - 1144-0546
SP - 1
EP - 9
PB - RSC
CY - Cambridge
AN - OPUS4-56147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
T1 - Kennwertermittlung für die Bewertung der Integrität einer Turbinenscheibe bei Überdrehzahl
N2 - Turbinenscheiben sind thermisch und mechanisch hochbeanspruchte, sicherheitsrelevante Komponenten in Gasturbinen. Ihre Integrität wird in Bauteiltests unter Überdrehzahlbedingungen nachgewiesen. Kontext des Aufsatzes ist die Erarbeitung einer zusätzlichen Bewertungsebene auf der Grundlage von Versuchen unter monotoner Beanspruchung, die die Beanspruchung im Bauteil realistisch wiedergeben soll. Dazu werden zwei Typen von bruchmechanischen Proben anwendungsnah ausgelegt und aus einer Turbinenscheibe ausgeschnitten: Der erste Typ ist eine biaxiale Probe, die die Beanspruchung und den Dehnungsbehinderungszustand am Diaphragm der Turbinenscheibe abbildet, die zweite eine bruchmechanische Probe, die die einachsige Beanspruchung und den Dehnungsbehinderungszustand am Bore der Turbinenscheibe wiedergibt.
Im Rahmen eines Schadentoleranzansatzkonzepts ist anschließend jeweils ein halbelliptischer Riss an den genannten Stellen der Turbinenscheibe zu betrachten. Mittels numerischer Berechnungen wird ein kritischer Punkt auf der Rissfront des Risses am Diaphragm bestimmt, dort wo die höchste Rissspitzenbelastung (J-Integral) auftritt. Auf der Basis der Rissspitzenbelastung, des Dehnungsbehinderungszustands und des entsprechenden Spannungsverhältnisses an diesem kritischen Punkt wird eine Kreuzprobe mit einem Durchriss konzipiert, die diese Verhältnisse im Bauteil widerspiegelt. Die Versuche werden unter der Temperatur am Diaphragm der Turbinenscheibe durchgeführt. Die J-R-Kurve und die plastische Kollapsgrenze werden bestimmt. Auch die einachsigen Versuche werden unter der Temperatur am Bore der Turbinenscheibe durchgeführt. Die Zugprobe enthält halbelliptische Oberflächenrisse. Ähnlich wie bei der Auslegung der Kreuzproben werden die Rissspitzenbelastung, der Dehnungsbehinderungszustand und das Spannungsverhältnis vergleichbar mit der Turbinenscheibe eingestellt. Die J-R-Kurve und die plastische Kollapsgrenze werden bestimmt.
Mit den Versuchsergebnissen werden die kritischen Lasten für verschiedene Versagensmechanismen (instabiles Risswachstum, plastischer Kollaps) der bruchmechanischen Proben ermittelt, die der kritischen Überdrehzahl der Turbinenscheibe entsprechen.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Turbine disk
KW - Fracture mechanics
KW - Biaxial test
KW - Burst
PY - 2022
AN - OPUS4-56148
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
T1 - New approach for multi material design: combination of laser beam and electromagnetic melt pool displacement by induced lorentz forces
N2 - Multi-material structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatial uncoupled from the influence of the keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction (EBSD) and EDX-Analysis. The detected intermetallic phases consist of a 5 µm - 6 µm compact phase seam of Al5.6Fe2 and a needle shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN.
T2 - ICALEO Orlando 2022
CY - Orlando, Florida, USA
DA - 17.10.2022
KW - Electromagnetic forces
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Steel and aluminium
PY - 2022
AN - OPUS4-56149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - Strahlenschutz beim Umgang mit Ultrakurzpuls-Lasern
N2 - Ultrakurzpuls-Lasertechnik ist heute der Schlüssel für eine Vielzahl von Anwendungen in der industriellen Lasermaterialbearbeitung. Beim Einsatz hoher Laser-Intensitäten kann allerdings unerwünschte Röntgenstrahlung erzeugt werden. Die Röntgendosis und Energieverteilung ist von Laser-, Material- und Prozessparametern abhängig. Es können Röntgendosen über den erlaubten Grenzwerten für die Exposition des Menschen erreicht werden.
T2 - Kolloquium des Bundesamtes für Strahlenschutz (BfS)
CY - Online meeting
DA - 29.09.2022
KW - Ultrakurze Laserpulse
KW - Materialbearbeitung
KW - Röntgenstrahlung
KW - Strahlenschutz
KW - Abschirmung
PY - 2022
AN - OPUS4-55893
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.I.
A1 - Nolze, Gert
A1 - Alymov, M.I.
T1 - Pore Morphology in Single Crystals of a Nickel-Based Superalloy After Hot Isostatic Pressing
N2 - The morphology of pores partially shrunk during a half-hour HIP at temperature of 1288 °C and pressure of 103 MPa has been investigated in nickel-based superalloy CMSX-4. The investigation resulted in the following findings: surrounding the shrinking pores by a c¢-shell (Ni3Al), faceting of the pores surface by {023} and {011} planes, and formation the submicroscopic satellite pores connected by channels with the neighboring larger pores. It is assumed that the formation of the c¢-shell around the pores and the faceting of the pore surface is due to diffusion processes occurring during pore shrinkage, and therefore these findings can be considered as arguments supporting the vacancy model of pore annihilation. The submicroscopic satellite pores are expected to be the result of dividing the casting pores of a complex initial shape during their shrinking. The connecting channels are probably required for the gas to escape from the rapidly shrinking small satellite pores into the slowly shrinking large pore. Thus, it is reasonable to assume that the casting pores may contain some amount of gas.
KW - HIP
KW - Superalloy
KW - Porosity
KW - Faceting
KW - negative crystal growth
PY - 2022
DO - https://doi.org/10.1007/s11661-022-06893-x
SN - 1073-5623
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-56409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Weathering Resistance of Halogen-free Flame Retardancy in E&E Plastics
N2 - - Durability of fire retardancy
- Impact of different exposure conditions
- Degradation with respect to different fire properties/tests
T2 - Fire Resistance in Plastics
CY - Cologne, Germany
DA - 28.11.2022
KW - Durability
KW - Flame retardant
KW - Thermoplastic Polyurethane
KW - Cable
KW - EVA
KW - Weathering
PY - 2022
AN - OPUS4-56444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Berger, Anka
T1 - BAM Research Programm - SAPT Related to the safe transport of polymerizing substances
N2 - Präsentation zum geplanten BAM-Forschungsvorhaben ("Safe transport of stabilized polymerizing substances: Investigation on the degradation of selected stabilizers"), bezogen auf den sicheren Transport (Straße, See) von polymerisierenden Substanzen. Der Schwerpunkt liegt dabei auf den systematischen Untersuchungen - mittels Thermal Activity Monitor (TAM IV) - zum zeitlichen Abbau des Stabilisators bei der Polymerisation sowie auf der Bestimmung der entsprechenden volumenabhängigen selbstbeschleunigenden Polymerisation (SAPT).
T2 - IGUS EOS ad hoc working groups - "Testing of solid oxidizers" / "Classification of energetic substances" / "Revision of test series H"
CY - Frankfurt am Main, Germany
DA - 21.11.2022
KW - SAPT
KW - Prüfserie-H
KW - Polymerisierende Stoffe
KW - Zeitlicher Abbau von Stabilisatoren
KW - Thermisches Verhalten
KW - Transport
KW - TAM IV
PY - 2022
AN - OPUS4-56474
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Particle-mediated origins of mesocrystalline disorder in calcium sulfate single crystals
N2 - Calcium sulfate minerals are abundant in natural and engineered environments and they exist in the form of three hydrates: gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5H2O), and anhydrite (CaSO4). Due to their relevance in natural and industrial processes, the formation pathways of these calcium sulfate phases from aqueous solution have been the subject of intensive research1.
The state-of-the-art of the calcium sulfate formation mechanisms builds upon and goes beyond what we have come to appreciate in the astounding intricacy of other mineral formation processes from ions in aqueous solutions. The original, and rather naive, 'textbook' image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species2. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. In this context, a number of studies have already revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of the different crystalline phases involves several steps including a common amorphous precursor1, 3, 4.
In this contribution we show that the formation of the amorphous phase involves the aggregation of small primary particles into larger disordered aggregates exhibiting a "brick-in-the-wall" structure5, 6. The actual crystallization occurs by the restructuring and coalescence of the particles ("bricks") into a given calcium sulfate phase depending on the physicochemical conditions of the solution. Importantly, the rearrangement process does not continue until a (nearly-)perfect homogeneous single crystal is obtained. Instead it comes to a stop, or at least significantly slows down. Such a process thus yields a final imperfect mesocrystal, composed of smaller domains rather than a continuous crystal structure, within which the domains are separated by an amorphous (i.e. less ordered) calcium sulfate phase.
Hence, the non-classical crystallization process of CaSO4 yields a final imperfect mesocrystal with an overall morphology resembling that of a single crystal, yet composed of smaller nano-domains. Importantly, these observations reveal that organic-free calcium sulfate mesocrystals grown by a particle mediated-pathway preserve in the final crystal structure a “memory” or “imprint” of their non-classical nucleation process, something that has been overlooked until now. Furthermore, the nano-scale misalignment of the structural sub-units within these crystals can propagate through the length-scales, and be expressed macroscopically as misaligned zones/domains in large single crystals (Fig. 1). Indeed, by considering large anhydrite crystals from the famous Naica Mine (“Cueva de los cristales”) we observed a suite of correlated self-similar void defects spanning multiple length-scales7 (Fig 2). These flaws, in the macroscopic crystal, stem from “seeds of imperfection” originating from a particle-mediated nucleation pathway. Hence, building a crystal could be viewed as Nature stacking blocks in a game of Tetris, whilst slowly forgetting the games core concept and failing to fill rows completely.
T2 - Granada Münster Discussion Meeting (GMDM)
CY - Granda, Spain
DA - 30.11.2022
KW - Anhydrite
KW - Mesocrystals
KW - Calcium sulfate
KW - Bassanite
KW - Gypsum
PY - 2022
AN - OPUS4-56476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chambers, Aaron
T1 - Synthesis of functionalized ZIF nanoparticles for effective composite formation
N2 - A presentation looking at ZIF-8 nanoparticles and functionalising them for more effective ZIF composite formation.
T2 - UoB/BAM mini conference
CY - Birmingham, UK
DA - 06.10.2022
KW - MOF composite
KW - 2PP
KW - ZIF-8
KW - Nanoparticles
PY - 2022
AN - OPUS4-56482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
T1 - New approach for multi-material design: Combination of laser beam and electromagnetic melt pool displacement by induced Lorentz forces
N2 - Multimaterial structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam, and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatially uncoupled from the influence of keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction and EDX analysis. The detected intermetallic phases consist of a 5–6 μm compact phase seam of Al5.6Fe2 and a needle-shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN.
KW - Electromagnetic forces
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Steel and aluminium
KW - Lorentz forces
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564840
DO - https://doi.org/10.2351/7.0000763
SN - 1042-346X
VL - 35
IS - 1
SP - 1
EP - 8
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-56484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Herausforderungen in der additiven Fertigung sicherheitsrelevanter Komponenten
N2 - Der Vortrag stellt nach einer kurzen allgemeinen Einleitung zur additiven Fertigung und des Laser Powder Bed Fusion Verfahrens einige Herausforderungen vor, die derzeitig den Einsatz von AM-Komponenten in sicherheitsrelevanten Anwendungen erschweren. Abschließend werden zwei Beispiele von Arbeiten der BAM gezeigt, die zur Überwindung dieser Herausforderungen beitragen können.
T2 - Anwendertreffen des Laserverbundes Berlin-Brandenburg
CY - Berlin, Germany
DA - 25.11.2022
KW - Additive Fertigung
KW - Laser Powder Bed Fusion
PY - 2022
AN - OPUS4-56435
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Junge, P.
A1 - Greinacher, M.
A1 - Kober, D.
A1 - Stargardt, Patrick
A1 - Rupprecht, C.
T1 - Metastable Phase Formation, Microstructure, and Dielectric Properties in Plasma-Sprayed Alumina Ceramic Coatings
N2 - The need for new solutions for electrical insulation is growing due to the increased electrification in numerous industrial sectors, opening the door for innovation. Plasma spraying is a fast and efficient way to deposit various ceramics as electrical insulators, which are used in conditions where polymers are not suitable. Alumina (Al2O3) is among the most employed ceramics in the coating industry since it exhibits good dielectric properties, high hardness, and high melting point, while still being cost-effective. Various parameters (e.g., feedstock type, spray distance, plasma power) significantly influence the resulting coating in terms of microstructure, porosity, and metastable phase formation. Consequently, these parameters need to be investigated to estimate the impact on the dielectric properties of plasma-sprayed alumina coatings. In this work, alumina coatings with different spray distances have been prepared via atmospheric plasma spray (APS) on copper substrates. The microstructure, porosity, and corresponding phase formation have been analyzed with optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Moreover, we present an in-depth analysis of the fundamental dielectric properties e.g., direct current (DC) resistance, breakdown strength, dielectric loss tangent, and permittivity. Our results show that decreasing spray distance reduces the resistivity from 6.31 × 109 Ωm (130 mm) to 6.33 × 108 Ωm (70 mm), while at the same time enhances the formation of the metastable δ-Al2O3 phase. Furthermore, space charge polarization is determined as the main polarization mechanism at low frequencies.
KW - Alumina
KW - Plasma spray
KW - Dielectric properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564394
DO - https://doi.org/10.3390/coatings12121847
SN - 2079-6412
VL - 12
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-56439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - GLAS DIGITAL - Datengetriebener Workflow für die beschleunigte Entwicklung von Glas
N2 - Aktuelle Ergebnisse des Projektes GlasDigital werden kurz zusammenfassend und allgemein verständlich vorgestellt.
T2 - MatFo 2022
CY - Cologne, Germany
DA - 14.11.2022
KW - Oxidglas
KW - robotische Glasschmelzanlage
KW - Ontologie
KW - ML
KW - Digitaler Zwilling
KW - Bildanalyse
PY - 2022
AN - OPUS4-56492
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - Glas Digital Datengetriebener Workflow für die beschleunigte Entwicklung von Glas
N2 - Der aktuelle Stand des Projektes GlasDigital wird in Kurzform präsentiert.
T2 - PMD Vollversammlung
CY - Online meeting
DA - 17.03.2022
KW - Oxidglas
KW - robotische Glasschmelzanlage
KW - Ontologie
KW - ML
KW - Digitaler Zwilling
KW - Bildanalyse
PY - 2022
AN - OPUS4-56493
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Vorstellung des WIPANOVerbundforschungsvorhabens GELELEK: Forschungsziele und Ergebnisse
N2 - Der Vortrag stellt das WIPANO-Forschungsvorhaben GELELEK vor und fasst die wichtigsten erzielten Ergebnisse zusammen.
T2 - Sitzung des GfKORR Arbeitskreises „Korrosion und Korrosionsschutz von Eisen und Stahl“
CY - Online meeting
DA - 08.12.2022
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosionsuntersuchungen
KW - Normung
KW - Ringversuch
KW - WIPANO
KW - Zink
KW - Korrosion
PY - 2022
AN - OPUS4-56502
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Haacke, Nasrin
T1 - Vorstellung des Forschungsprojektes RUNOFF: "Neubewertung der Dauerhaftigkeit von Dach- und Fassadenmaterialien und des Eintrags von Schwermetallionen in die Umwelt hervorgerufen durch Runoff„
N2 - Der Vortrag stellt das Forschungsprojekt RUNOFF vor und geht auf das geplante Arbeitsprogramm ein. Darüber hinaus wird die Problemstellung erläutert.
T2 - Klempnerfachtagung des Zentralverbands Sanitär-Heizung-Klima
CY - Karlstadt a. M., Germany
DA - 11.10.2022
KW - Korrosion
KW - Kupfer
KW - Runoff
KW - Zink
KW - Atmosphärische Korrosion
PY - 2022
AN - OPUS4-56045
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nasr Esfahani, M.
A1 - Zare Pakzad, S.
A1 - Li, T.
A1 - Li, X.
A1 - Tasdemir, Z.
A1 - Wollschläger, Nicole
A1 - Leblebici, Y.
A1 - Erdem Alaca, B.
T1 - Effect of Native Oxide on Stress in Silicon Nanowires: Implications for Nanoelectromechanical Systems
N2 - Understanding the origins of intrinsic stress in Si nanowires (NWs) is crucial for their successful utilization as transducer building blocks in next-generation, miniaturized sensors based on anoelectromechanical systems (NEMS). With their small size leading to ultrahigh-resonance frequencies and extreme surface-to-volume ratios, silicon NWs raise new opportunities regarding sensitivity, precision, and speed in both physical and biochemical sensing. With silicon optoelectromechanical properties strongly dependent on the level of NW intrinsic stress, various studies have been devoted to the measurement of such stresses generated, for example, as a result of harsh fabrication processes. However, due to enormous NW surface area, even the native oxide that is conventionally considered as a benign surface condition can cause significant stresses. To address this issue, a combination of nanomechanical characterization and atomistic simulation approaches is developed. Relying only on low-temperature processes, the fabrication approach yields monolithic NWs with optimum boundary conditions, where NWs and support architecture are etched within the same silicon crystal. Resulting NWs are characterized by transmission electron microscopy and micro-Raman spectroscopy. The interpretation of results is carried out through molecular dynamics simulations with ReaxFF potential facilitating the incorporation of humidity and temperature, thereby providing a close replica of the actual oxidation environment - in contrast to previous dry oxidation or self-limiting thermal oxidation studies. As a result, consensus on significant intrinsic tensile stresses on the order of 100 MPa to 1 GPa was achieved as a function of NW critical dimension and aspect ratio. The understanding developed herein regarding the role of native oxide played in the generation of NW intrinsic stresses is important for the design and development of silicon-based NEMS.
KW - Nanoelectromechanical systems (NEMS)
KW - Silicon nanowires
KW - Native oxide
KW - Intrinsic stress
KW - Raman spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560471
DO - https://doi.org/10.1021/acsanm.2c02983
SN - 2574-0970
VL - 5
SP - 13276
EP - 13285
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, M.
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
A1 - Binder, M.
A1 - Dollmeier, K.
A1 - Dreyer, M.
A1 - Klöden, B.
A1 - Schlingmann, T.
A1 - Schmidt, J.
T1 - Reproducibility and Scattering in Additive Manufacturing: Results from a Round Robin on PBF-LB/M AlSi10Mg Alloy
T1 - Reproduzierbarkeit und Streuung bei der additiven Fertigung: Ergebnisse eines Ringversuchs mit einer PBF-LB/M AlSi10Mg-Legierung
N2 - The round robin test investigated the reliability users can expect for AlSi10Mg additive manufactured specimens by laser powder bed fusion through examining powder quality, process parameter, microstructure defects, strength and fatigue. Besides for one outlier, expected static material properties could be found. Optical microstructure inspection was beneficial to determine true porosity and porosity types to explain the occurring scatter in properties. Fractographic analyses reveal that the fatigue crack propagation starts at the rough as-built surface for all specimens. Statistical analysis of the scatter in fatigue using statistical derived safety factors concludes that at a stress of 36.87 MPa the fatigue limit of 107 cycles could be reached for all specimen with a survival probability of 99.999 %.
N2 - Im Rahmen eines Ringversuchs wurde durch die Untersuchung der Pulverqualität, der Prozessparameter, der Gefügefehler, der Festigkeit und der Ermüdung die Zuverlässigkeit bestimmt, die Nutzer von AlSi10Mg-Proben erwarten können, die mit pulverbettbasiertes Schmelzen mittels Laser (engl. Laser Powder Bed Fusion) gefertigt worden sind. Abgesehen von einem Ausreißer wurden die erwarteten statischen Materialeigenschaften erreicht. Eine optische Gefügeprüfung diente dazu, die tatsächliche Porosität und Arten von Porosität zu ermitteln, um die bei den Eigenschaften auftretende Streuung zu erklären. Fraktographische Unterschungen zeigen eine bei allen Proben von der rauen Oberfläche im As-built-Zustand ausgehende Ermüdungsrissausbreitung. Aus der statistischen Analyse der Streuung bezüglich der Ermüdung unter Anwendung von statistischen abgeleiteten Sicherheitsfaktoren geht hervor, dass alle Proben die Dauerfestigkeit von 107 Zyklen bei einer Spannung von 36,87 MPa mit einer Überlebenswahrscheinlichkeit von 99,999 % erreichten.
KW - Additive manufacturing
KW - Reproducibility
KW - Reliability
PY - 2022
DO - https://doi.org/10.1515/pm-2022-1018
SN - 2195-8599
VL - 59
IS - 10
SP - 580
EP - 614
PB - De Gruyter
AN - OPUS4-55935
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hemmleb, M.
T1 - Integrated topographic SEM imaging for software assisted fractography
N2 - The aim of a fractographic investigation is the evaluation of macroscopic and microscopic fracture surface characteristics and, as a result, the determination of the fracture mechanism of a component from a failure case. The basis for such evaluations of fracture characteristics comes from actual comparative mechanical testing and from the literature. A fractographic analysis can be very complex and, in any case, requires considerable experience.
Machine learning methods enables the quantitative determination of fracture characteristics and fracture mechanisms utilizing digitized expert knowledge [1]. Although the application of SE images provides promising results, additional information is required to obtain reliable solutions. As expected, BSE and 3D information helps to improve the classification (Fig. 1). But only a fast, widely integrated, and automated topography measurement can provide the required amount of referenced surface data for the application of machine learning methods.
To fulfil these requirements, topographical data are obtained from a BSE detector with four symmetric segments (4Q-BSE) using shape-from-shading technology [2]. Surface height calculation is performed live during image acquisition and provides immediate feedback in three dimensions. All available signals (SE, BSE and more if applicable) are recorded simultaneously together with the surface topography and stored in a multichannel data file. This guaranties the same geometrical reference for all data, which is required for further analysis (Fig. 2).
When applying machine learning methods to topographic data together with SEM images, topographic information must be provided as depth image. Consequently, a unique height scale is required for all applied data with different magnifications. This requires a calibrated height measurement, which is ensured with the integrated 3D calibration of the topographic acquisition and a dedicated calibration sample. Thus, a large number of data sets from different fracture samples was generated and used as training data for machine learning.
T2 - 16th Multinational Congress on Microscopy
CY - Brno, Czech Republic
DA - 04.09.2022
KW - Fractography
KW - Machine Learning
KW - Topography
PY - 2022
AN - OPUS4-55937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmies, Lennart
T1 - Using Machine Learning and Topographic SEM Imaging for Software Assisted Fractography
N2 - The aim of a fractographic investigation is the evaluation of macroscopic and microscopic fracture surface characteristics and, as a result, the determination of the fracture mechanism of a component from a failure case. The basis for such evaluations of fracture characteristics comes from actual comparative mechanical testing and from the literature. A fractographic analysis can be very complex and, in any case, requires considerable experience. In the IGF project "iFrakto", software is being developed that quantitatively determines fracture characteristics and fracture mechanisms utilizing digitized expert knowledge, machine learning, and standard 2D and topographical data from SEM imaging. Topographical data are obtained from 4QBSE detector using shape-from-shading technology. In the medium term, a software tool should provide knowledge-based suggestions for the evaluation of fracture surfaces in real time during SEM work or at subsequent evaluation. As a basis for this, round robins were carried out among fractographers in order to create a knowledge base, to query the practice-relevant requirements for such tools and to carry out first practical tests. Actual results are presented and the relevance of the evaluation strategy is evaluated.
T2 - Material Science and Engineering 2022
CY - Darmstadt, Germany
DA - 27.9.2022
KW - Fractography
KW - Machine Learning
KW - Topography
PY - 2022
AN - OPUS4-55938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sonntag, U.
T1 - Softwaregestützte Bestimmung von Bruchmechanismen und Bruchflächenmerkmalen mittels Machine Learning und Topographie-Informationen
N2 - Ziel von fraktographischen Untersuchungen ist die Auswertung von makroskopischen und mikroskopischen Bruchflächenmerkmalen und daraus resultierend die Bestimmung des Bruchmechanismus eines Bauteils aus einem Schadensfall. Die Grundlage für die Bewertung von Bruchmerkmalen stammt dabei aus zuvor durchgeführten eigenen Vergleichsversuchen und aus der Literatur. Eine fraktographische Analyse kann sehr aufwändig sein und setzt in jedem Fall erhebliches Erfahrungswissen voraus. Im IGF-Vorhaben „iFrakto“ wird Software entwickelt, die auf Basis von digitalisiertem Expertenwissen, Machine Learning und unter Zuhilfenahme von Topographie-Daten anhand von REM-Aufnahmen Bruchmerkmale und Bruchmechanismen quantitativ bestimmt, s. Abbildung. Solche Software soll mittelfristig direkt am REM oder bei der nachfolgenden Auswertung wissensbasierte Vorschläge für die Bewertung von Bruchflächen liefern. Als Grundlage hierfür wurden Ringversuche unter Fraktograph/inn/en durchgeführt, um die Wissensbasis zu schaffen, die praxisrelevanten Anforderungen an solche Software abzufragen und erste Praxistests durchzuführen. Die bisherigen Ergebnisse werden vorgestellt und die Relevanz der Auswertestrategie und unterschiedlicher Sensordaten bewertet.
T2 - 56. Metallographie-Tagung
CY - Saarbrücken, Germany
DA - 21.9.2022
KW - Fraktographie
KW - Machine Learning
KW - Topographie
PY - 2022
AN - OPUS4-55939
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Einlagiges MSG-Hochleistungsschweißen von dickwandigen Baustählen mit kontaktloser elektromagnetischer Schmelzbadsicherung
N2 - Diese Arbeit zeigt erstmals die Anwendung einer elektromagnetischen Schmelzbadstütze beim einlagigen MSG-Schweißen von dickwandigen Stählen. Die innovativen Entwicklungen im Bereich des Lichtbogenschweißverfahrens ermöglichen eine Erhöhung der Abschmelzleistung, um die Einschweißtiefe zu steigern. Somit kann die Lagenanzahl reduziert und die Produktivität gesteigert werden. Allerdings besteht insbesondere beim einlagigen Schweißen von dickwandigen Bauteilen in PA-Position ein erhöhtes Risiko für das gravitationsbedingte Austropfen der Schmelze an der Wurzel. Zur Verhinderung werden Badstützen eingesetzt, die mechanisch angebracht und nach dem Schweißen entfernt werden müssen, was zeit- und kostenintensiv ist.
Die im Rahmen dieser Studie eingesetzte elektromagnetische Schmelzbadstütze wirkt dem gravitationsbedingten Austropfen der Schmelze entgegen und kompensiert den hydrostatischen Druck. Sie wirkt kontaktlos, was im Gegensatz zu herkömmlichen Badstützen vorteilhaft ist, so dass auf eine zeit- und kostenintensive Nachbearbeitung der Schweißnahtwurzel verzichtet werden kann. Das auf extern angelegten oszillierenden Magnetfeldern beruhende Verfahren wird dabei unterhalb des zu schweißenden Bauteils positioniert. Die Magnetfeldlinien sind quer zur Schweißrichtung ausgerichtet, sodass längs zur Schweißrichtung Wirbelströme im Werkstück und eine stets nach oben gerichtete Lorentzkraft generiert werden. Mit Hilfe der elektromagnetischen Badstütze konnten beim einlagigen MSG-Schweißen von 8 mm bis 12 mm die Tropfenbildung vermieden werden. Die innovative Technologie ermöglicht es dickwandige Bauteile einlagig zu schweißen und reduziert die Nachbearbeitungszeit deutlich.
T2 - DVS Congress 2022 - Große Schweißtechnische Tagung
CY - Koblenz, Germany
DA - 19.09.2022
KW - Hochleistungsschweißen
KW - MSG-Schweißen
KW - Elektromagnetische Schmelzbadsicherung
PY - 2022
AN - OPUS4-56368
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Stainless steels: Fundamentals and causes for corrosion defects
N2 - The presentation gives an overview about the fundamentals on stainless steels. The mechanism of passive layer formation is explained and strategies for securing corrosion protection are given. The influence of a grinding process on corrosion resistance is discussed.
T2 - Tech-Day Mettler Toledo
CY - Online meeting
DA - 23.11.2022
KW - Corrosion
KW - Stainless steel
KW - Grinding
KW - KorroPad
KW - Surface
PY - 2022
AN - OPUS4-56370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - QI-Digital - Qualitätssicherung für die Additive Fertigung
N2 - Für die konventionelle Fertigung hat sich das bestehende System der Qualitätsinfrastruktur (QI) bewährt. Die additive Fertigung vergrößert den gestalterischen Spielraum von möglichen Bauteilgeometrien und Prozessfehlern jedoch erheblich. Hier gerät die QI an ihre Grenzen, sodass die Fertigung und Zulassung sicherheits-relevanter Bauteile sehr zeit- und kostenintensive Versuche erfordern. Eine moderne digitale QI erlaubt eine effizientere Qualitätssicherung für additiv gefertigte Bauteile. Dies erfordert eine durchgängig digitale Abbildung des physischen Materialflusses.
T2 - QI-Forum
CY - Berlin, Germany
DA - 11.10.2022
KW - Additive Fertigung
KW - Qualitätssicherung
KW - Digitalisierung
PY - 2022
AN - OPUS4-56382
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitalisierung der Qualitätsinfrastruktur am Beispiel der Additiven Fertigung
N2 - Die Digitalisierung der Qualitätsinfrastruktur (QI) am Beispiel der Additiven Fertigung. Der Vortrag erörtert, wie man mit Elementen einer digitalen QI (DPP, DCoC, Smart Standard, DCC, etc.) aktuelle Herausforderungen in der Qualitätssicherung additiv gefertigter Bauteile adressieren kann.
T2 - FORUM Qualitätssicherung in der additiven Fertigung – Quality Engineering
CY - Online meeting
DA - 13.09.2022
KW - Additive Fertigung
KW - Qualitätssicherung
KW - Digitalisierung
KW - Qualitätsinfrastruktur
PY - 2022
AN - OPUS4-56383
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meyer, Lena
T1 - Additive Fertigung unter Mikrogravitationsbedingungen für Anwendungen im Weltraum
N2 - Präsentation der Aktivitäten an der BAM im Bereich Additive Fertigung unter Mikrogravitationsbedingungen für Anwendungen im Weltraum beim Arbeitsgruppentreffen der AG Werkstoffe & Prozesse vom Netzwerk Space2Motion.
T2 - Arbeitsgruppentreffen beim Netzwerk Space2Motion
CY - Online meeting
DA - 09.11.2022
KW - Additive Fertigung
KW - Mikrogravitation
PY - 2022
AN - OPUS4-56353
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
T1 - Numerical analysis of the influence of an auxiliary oscillating magnetic field on suppressing the porosity formation in deep penetration laser beam welding of aluminum alloys
N2 - The contactless magnetohydrodynamic technology has been considered as a potential and promising method to improve the weld qualities of deep penetration laser beam welding. In this paper, numerical investigations are conducted to study the influence of the auxiliary oscillating magnetic field on the porosity suppression in laser beam welding of 5754 aluminum alloy. To obtain a deeper insight into the suppression mechanism, a three-dimensional transient multi-physical model is developed to calculate the heat transfer, fluid flow, keyhole dynamic, and magnetohydrodynamics. A ray tracing algorithm is employed to calculate the laser energy distribution on the keyhole wall. A time-averaged downward Lorentz force is produced by an oscillating magnetic field. This force acts in the molten pool, leading to a dominant downward flow motion in the longitudinal section, which blocks the bubble migration from the keyhole tip to the rear part of the molten pool. Therefore, the possibility for the bubbles to be captured by the solidification front is reduced. The electromagnetic expulsive force provides an additional upward escaping speed for the bubbles of 1 m/s ~ 5 m/s in the lower and middle region of the molten pool. The simulation results are in a good agreement with experimental measurements. Based on the results obtained in this study, a better understanding of the underlying physics in laser beam welding enhanced by an auxiliary oscillating magnetic field can be provided and thus the welding process can be further optimized reducing the porosity formation.
T2 - The 13th International Seminar "Numerical Analysis of Weldability"
CY - Graz, Austria
DA - 04.09.2022
KW - Deep penetration laser beam welding
KW - Oscillating magnetic field
KW - Numerical simulation
KW - Porosity
KW - Molten pool behaviour
PY - 2022
AN - OPUS4-56328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding
N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. First, the local variation of the solidification sequence of the weld pool causes an increase in the hotcracking susceptibility due to a locally delayed solidification. Second, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g., during the welding with filler materials, is blocked. This leads to a nonhomogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results that were supported by selected experimental validation results.
T2 - International Congress of Applications of Lasers & Electro-Optics 2022
CY - Orlando, FL, USA
DA - 17.10.2022
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
KW - Porosity
KW - Element distribution
KW - Numerical process simulation
PY - 2022
AN - OPUS4-56335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Surface nanotexturing by ultrashort laser pulses
N2 - The presentation reviews the BAM activities in the field of surface processing by ultrashort laser pulses. A focus is laid on the generation of laser-induced periodic surface structures (LIPSS) which allow various surface functionalizations for applications in optics, tribology, liquid management, and medicine.
T2 - Photonics Days Berlin Brandenburg 2022
CY - Berlin, Germany
DA - 05.10.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser
KW - Surface functionalization
PY - 2022
AN - OPUS4-55921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiehle, Philipp
A1 - Brinkmann, M.
T1 - Material behaviour of unstabilised earth block masonry and its components under compression at varying relative humidity
N2 - block and mortar types is analysed with particular regard to the influence of varying relative humidity. The uniaxial compressive strength and deformation characteristics of unstabilised earth blocks and mortars as well as of unstabilised earth block masonry are studied in detail and compared to conventional masonry to evaluate whether the structural design can be made accordingly. An increase of 30 % points in relative humidity leads to a reduction of the masonry´s compressive strength between 33 % and 35 % whereas the Young´s modulus is reduced by 24–29 %. However, the ratio between the Young´s modulus and the characteristic compressive strength of earth block masonry ranges between E33/fk = 283–583 but is largely independent of the relative humidity. The results show that the mechanical properties of the investigated unstabilised earth block masonry are sufficient for load-bearing structures, yielding a masonry compressive strength between 2.3 MPa and 3.7 MPa throughout the range of moisture contents
investigated. In general, the design concept of conventional masonry can be adapted for unstabilised earth masonry provided that the rather low Young´s modulus as well as the moisture dependence of both, compressive strength and Young´s modulus, are sufficiently taken into
account.
KW - Compressive strength
KW - Earth block masonry
KW - Compression tests
KW - Stress-strain relation
KW - Relative humidity
KW - Moisture content
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562417
DO - https://doi.org/10.1016/j.cscm.2022.e01663
SN - 2214-5095
VL - 17
SP - 1
EP - 15
PB - Elsevier B.V.
CY - Netherlands
AN - OPUS4-56241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Particle-mediated origins of mesocrystalline disorder in calcium sulfate single crystals
N2 - Calcium sulfate minerals are abundant in natural and engineered environments and they exist in the form of three hydrates: gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5H2O), and anhydrite (CaSO4). Due to their relevance in natural and industrial processes, the formation pathways of these calcium sulfate phases from aqueous solution have been the subject of intensive research1.
The state-of-the-art of the calcium sulfate formation mechanisms builds upon and goes beyond what we have come to appreciate in the astounding intricacy of other mineral formation processes from ions in aqueous solutions. The original, and rather naive, 'textbook' image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species2. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. In this context, a number of studies have already revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of the different crystalline phases involves several steps including a common amorphous precursor1, 3, 4.
In this contribution we show that the formation of the amorphous phase involves the aggregation of small primary particles into larger disordered aggregates exhibiting a "brick-in-the-wall" structure5, 6. The actual crystallization occurs by the restructuring and coalescence of the particles ("bricks") into a given calcium sulfate phase depending on the physicochemical conditions of the solution. Importantly, the rearrangement process does not continue until a (nearly-)perfect homogeneous single crystal is obtained. Instead it comes to a stop, or at least significantly slows down. Such a process thus yields a final imperfect mesocrystal, composed of smaller domains rather than a continuous crystal structure, within which the domains are separated by an amorphous (i.e. less ordered) calcium sulfate phase.
Hence, the non-classical crystallization process of CaSO4 yields a final imperfect mesocrystal with an overall morphology resembling that of a single crystal, yet composed of smaller nano-domains. Importantly, these observations reveal that organic-free calcium sulfate mesocrystals grown by a particle mediated-pathway preserve in the final crystal structure a “memory” or “imprint” of their non-classical nucleation process, something that has been overlooked until now. Furthermore, the nano-scale misalignment of the structural sub-units within these crystals can propagate through the length-scales, and be expressed macroscopically as misaligned zones/domains in large single crystals. Indeed, by considering large anhydrite crystals from the famous Naica Mine (“Cueva de los cristales”) we observed a suite of correlated self-similar void defects spanning multiple length-scales7. These flaws, in the macroscopic crystal, stem from “seeds of imperfection” originating from a particle-mediated nucleation pathway. Hence, building a crystal could be viewed as Nature stacking blocks in a game of Tetris, whilst slowly forgetting the games core concept and failing to fill rows completely.
T2 - ECCG: European Conference on Crystal Growth 7
CY - Paris, France
DA - 25.07.2022
KW - Anhydrite
KW - SAXS
KW - Single crystal
KW - Mesocrystal
PY - 2022
AN - OPUS4-56276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Particle-mediated origins of mesocrystallinity in calcium sulfate single crystals
N2 - Calcium sulfate minerals are abundant in natural and engineered environments in the form of three phases: gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5H2O), and anhydrite (CaSO4). Due to their relevance in natural and industrial processes, the formation pathways of these phases from aqueous solution have been the subject of intensive research, a number of studies have already revealed that nucleation in the CaSO4-H2O system is non-classical, The formation of the different crystalline phases involves several steps including a common amorphous precursor.
In this contribution we show that the formation of the amorphous phase involves the aggregation of small primary particles into larger disordered aggregates exhibiting a "brick-in-the-wall" structure. The actual crystallization occurs by the restructuring and coalescence of the "bricks" into a given calcium sulfate phase depending on the physicochemical conditions of the solution. Such a process yields a final imperfect mesocrystal, composed of smaller domains rather than a continuous single crystal structure.
These observations reveal that organic-free calcium sulfate mesocrystals grown by a particle mediated-pathway might preserve in the final crystal structure an “imprint” of their growth pathways. Indeed, by considering large anhydrite crystals from the famous Naica Mine we observed a suite of correlated self-similar void defects spanning multiple length-scales. These flaws, in the macroscopic crystal, stem from “seeds of imperfection” originating from an original particle-mediated growth. Hence, building a crystal could be viewed as Nature stacking blocks in a game of Tetris, whilst slowly forgetting the games core concept and failing to fill rows completely.
T2 - GeoMinKöln 2022
CY - Cologne, Germany
DA - 11.09.2022
KW - Anhydrite
KW - Mesocrystals
KW - Calcium sulfate
PY - 2022
AN - OPUS4-56277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - GlasDigital - Datengetriebener Workflow für die beschleunigte Entwicklung von Glas
N2 - Das Projekt GlasDigital im Rahmen der BMBF Initiative MaterialDigital wird vorgestellt.
T2 - MatFo22
CY - Berlin, Germany
DA - 14.11.2022
KW - Material Digital
PY - 2022
AN - OPUS4-56282
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Bähring, S.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Prognose von Qualitätsmerkmalen durch Anwendung von KI-Methoden beim Directed 10 Energy Deposition
N2 - Dieser Beitrag enthält die Ergebnisse eines im Rahmen der DVS Forschung entwickelten Ansatzes zur Qualitätssicherung im Directed Energy Deposition. Es basiert auf der Verarbeitung verschiedener während des Prozesses gesammelter Sensordaten unter Anwendung Künstlicher Neuronale Netze (KNN). So ließen sich die Qualitätsmerkmale Härte und Dichte auf der Datenbasis von 50 additiv gefertigten Probenwürfel mit einer Abweichung < 2 % vorhersagen. Des Weiteren wurde die Übertragbarkeit des KNN auf eine Schaufelgeometrie untersucht. Auch hier ließen sich Härte und Dichte hervorragend prognostizieren (Abweichung < 1,5 %), sodass der Ansatz als validiert betrachtet werden kann.
KW - Kl
KW - Directed Energy Depositio
KW - Qualitätssicherung
PY - 2022
SN - 0036-7184
VL - 74
IS - 10
SP - 672
EP - 679
PB - DVS Media
CY - Düsseldorf
AN - OPUS4-56284
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - KorroPad Prüfung in der industriellen Praxis
N2 - Anwendungsbeispiele aus dem industrielle Umfeld und Ausblick für weitere Entwicklungen des KorroPads.
T2 - GfKORR Jahrestagung - Aktuelles aus der Korrosionsforschung - Nutzen und praktische Anwendungen
CY - Frankfurt a.M., Germany
DA - 08.11.2022
KW - Korrosion
KW - Nichtrostender Stahl
KW - KorroPad
KW - Korrosionsprüfung
PY - 2022
AN - OPUS4-56205
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Lean Duplex als alternative Güte zu Standardausteniten im Bauwesen
N2 - Dieser Vortrag stellt die technologischen und industriellen Meilensteine bei der Etablierung von Lean Duplex Stählen im Bereich des Bauwesens vor. Ein weiterer Blick geht auf die weiteren Entwicklungen an der BAM hinsichtlich der Ausweitung der Kapazitäten und Standorte atmosphärischer Bewitterungsstände der BAM.
T2 - GfKORR Jahrestagung 2022
CY - Frankfurt am Main, Germany
DA - 08.11.2022
KW - Korrosion
KW - Bauwesen
KW - Duplexstähle
KW - Offshore
KW - Tunnel
PY - 2022
AN - OPUS4-56198
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
T1 - Innenhydrophobierung von Fahrbahndeckenbetonen als AKR-Vermeidungsstrategie
N2 - An den vor allem vor 2006 errichteten Betonfahrbahndecken sind in den letzten Jahren vermehrt AKR-Schäden aufgetreten. Vor diesem Hintergrund wurde durch das BMVBS das ARS 04/2013 erlassen. Dieses wiederum sieht verbindlich im Vorfeld des Neubaus und der Erneuerung von Fahrbahndecken aus Beton im deutschen Bundesautobahnnetz einen Eignungsnachweis für die Gesteinskörnungen vor. Das hatte in den Folgejahren eine drastische Reduzierung der einsatzbaren Gesteinskörnungen zur Folge. Vor diesem Hintergrund wird in dem Beitrag die Leistungsfähigkeit der Innenhydrophobierung als neuartige AKR-Vermeidungsstrategie zur Nutzbarmachung grenzwertig alkaliempfindlicher Gesteinskörnungen aufgezeigt. Dabei wird ein Einblick in die Ergebnisse zweier aufeinander aufbauender BASt-Forschungsvorhaben gegeben. Den Schwerpunkt bildet hierbei die Bewertung des Einflusses der Dosierung des Hydrophobierungsmittels auf die Frisch- und Festbetoneigenschaften im Rahmen von Basisuntersuchungen im Labor. Aufbauend darauf wird das Prüfprogramm eines großmaßstäblichen Technikumsversuchs und der aktuelle Stand der Umsetzung aufgezeigt.
T2 - 4. Forschungskolloquium Betonstraßenbau
CY - Dresden, Germany
DA - 19.01.2023
KW - Alkali-Kieselsäure-Reaktion
KW - Betonfahrbahndecke
KW - AKR-Vermeidung
KW - Innenhydrophobierung
PY - 2023
AN - OPUS4-56869
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shi, L.
A1 - Chen, J.
A1 - Yang, Chunliang
A1 - Chen, G.
A1 - Wu, C.
T1 - Thermal-fluid-structure coupling analysis of void defect in friction stir welding
N2 - Understanding the void defect formation mechanism and simultaneous predicting the tool service life in friction stir welding are critical for optimizing the welding parameters. However, the void defect formation mechanism in friction stir welding is not yet elucidated. In this study, a novel integrated thermal-fluid-structure coupling model of the friction stir welding process was proposed for simultaneous prediction of the weld formation and tool service life. A new non-uniform distribution model of the tool-workpiece contact pressure was proposed to describe the interaction between the tool and the workpiece. The void defect formation mechanism was quantitatively studied using the proposed integrated thermal-fluid-structure coupling model. The results show that the plastic material flows in the horizontal direction and can completely fill the cavity behind the tool for the welding condition of forming a sound weld. While the tool-workpiece contact interfacial frictional shear stress in the rear of the tool is decreased significantly which leads to a severe decrease in the plastic material flow velocity. Therefore, after bypassing the tool from the retreating side, the plastic material at the bottom of the weld stagnates, and void defect forms in the middle and lower part of the weld at the advancing side. The difference between the maximum and the minimum tool-workpiece contact pressure could serve as a numerical criterion to predict void defects. A sound joint is formed when the difference is lower than the critical value of 15 MPa, while a void defect is formed in the weld if it is higher than this critical value. The maximum equivalent stress acting on the tool is located at the pin root with severe stress concentration at a high welding speed. The front of the tool is subjected to tensile stress while its rear is subjected to compressive stress, therefore the tool is apt to fracture at its root under an inappropriate welding condition. The average normal stress of the tool varies periodically with its period consistent with the rotation period of the tool. The service life of the tool is decreased with the increase in welding speed and the decrease in rotation speed. The model is validated by experimental results.
KW - Friction stir welding
KW - Thermal-fluid-structure coupling model
KW - Tool-workpiece interaction
KW - Void defect formation mechanism
KW - Tool service life
PY - 2023
DO - https://doi.org/10.1016/j.ijmecsci.2022.107969
SN - 0020-7403
VL - 241
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-56929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merz, Benjamin
A1 - Nilsson, R.
A1 - Garske, C.
A1 - Hilgenberg, Kai
T1 - Camera-based high precision position detection for hybrid additive manufacturing with laser powder bed fusion
N2 - Additive manufacturing (AM) in general and laser powder bed fusion (PBF-LB/M) in particular are becoming increasingly important in the field of production technologies. Especially the high achievable accuracies and the great freedom in design make PBF-LB/M interesting for the manufacturing and repair of gas turbine blades. Part repair involves building AM-geometries onto an existing component. To minimise the offset between component and AM-geometry, a precise knowledge of the position of the component in the PBF-LB/M machine is mandatory. However, components cannot be inserted into the PBF-LB/M machine with repeatable accuracy, so the actual position will differ for each part. For an offset-free build-up, the actual position of the component in the PBF-LB/M machine has to be determined. In this paper, a camera-based position detection system is developed considering PBF-LB/M constraints and system requirements. This includes finding an optimal camera position considering the spatial limitations of the PBF-LB/M machine and analysing the resulting process coordinate systems. In addition, a workflow is developed to align different coordinate systems and simultaneously correct the perspective distortion in the acquired camera images. Thus, position characteristics can be determined from images by image moments. For this purpose, different image segmentation algorithms are compared. The precision of the system developed is evaluated in tests with 2D objects. A precision of up to 30μm in translational direction and an angular precision of 0.021∘ is achieved. Finally, a 3D demonstrator was built using this proposed hybrid strategy. The offset between base component and AM-geometry is determined by 3D scanning and is 69μm.
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Hybrid repair
KW - Machine vision
KW - Image processing
KW - Position detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568583
DO - https://doi.org/10.1007/s00170-022-10691-5
SP - 1
EP - 16
PB - Springer
AN - OPUS4-56858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abed, Jehad
A1 - Bai, Yanh
A1 - Persaud, Daniel
A1 - Kim, Jiheon
A1 - Witt, Julia
A1 - Hattrick.Simpers, Jason
A1 - Sargent, Edward
T1 - AMPERE: automated modular platform for expedited and reproducible electrochemical testing
N2 - Rapid and reliable electrochemical screening is critical to accelerate the development of catalysts for sustainable energy generation and storage. This paper introduces an automated and modular platform for expedited and reproducible electrochemical testing (AMPERE), designed to enhance the efficiency and reliability of multivariate optimization. The platform integrates a liquid-handling robot with custommade modular array reactors, offering sample preparation and electrochemical testing in the same platform. Additionally, we use offline inductively coupled plasma optical emission spectroscopy (ICPOES) to measure metal concentrations in the electrolyte after the reaction, which serves as a proxy for assessing the electrochemical stability. We use the platform to conduct 168 experiments continuously in less than 40 hours to examine the influence of catalyst ink formulation on the performance of Ir, Ru, IrO2, and RuO2 for the oxygen evolution reaction (OER) in acid. We specifically investigate the role of solvent type and concentration, catalyst concentration, and binder content on the performance. We find that Ru/RuO2 catalysts show improvements in activity that are not directly linked to improvements in the electrochemical surface area or inversely correlated to Ru dissolution. This suggests a complex interplay between the catalytic performance of the drop-casted catalyst film and ink formulation. AMPERE simplifies catalyst preparation and testing at large scale, making it faster, more reliable, and accessible for
widespread use.
KW - Electrochemical screening
KW - Automated platform
KW - Catalysis
KW - Energy generation and storage
KW - Oxygen evolution reaction (OER)
KW - MAPz@BAM
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614724
DO - https://doi.org/10.1039/d4dd00203b
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Phonon-accurate machine-learning potentials from automated workflows
N2 - Data-driven materials design aims to predict and optimise material properties, such as stability and thermal conductivity, that are influenced by vibrational behaviour. Approaches such as DFT are computationally demanding and have limitations for phonon calculations. Machine learning based interatomic potentials (MLIP), such as the Gaussian Approximation Potential (GAP), offer a more efficient alternative. We have developed a Python workflow to automate MLIP generation using the Materials Project database. DFT calculations, MLIP fitting and benchmarking steps are automated. This approach speeds up phonon calculations and allows testing of different data generation strategies and hyperparameters. Our goal is to provide open source and share these capabilities to improve reproducibility and accessibility in computational chemistry. This talk will provide a hih-level overview of the automated software and recent preliminary results.
T2 - Berlin PostDoc Day 2024
CY - Berlin, Germany
DA - 07.11.2024
KW - Interatomic potentials
KW - Machine learning
KW - Phonons
KW - Thermoelectrics
KW - Automated workflows
PY - 2024
AN - OPUS4-61576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kellermeier, Matthias
A1 - Scheck, Johanna
A1 - Drechsler, Markus
A1 - Rosenberg, Rose
A1 - Stawski, Tomasz
A1 - Fernandez-Martinez, Alejandro
A1 - Gebauer, Denis
A1 - Van Driessche, Alexander E. S.
T1 - From Ions to Crystals: A Comprehensive View of the Non‐Classical Nucleation of Calcium Sulfate
N2 - After years of intensive research and numerous important observations, our understanding of the early stages of crystallization is still limited due to the complexity of the underlying processes and their elusive character. In the present work, we provide a detailed view on the nucleation of calcium sulfate mineralization – an abundant mineral with broad use in construction industry – in aqueous systems at ambient conditions. As experimental basis, a co‐titration procedure with potentiometric, turbidimetric and conductometric detection was developed, allowing solution speciation and the formation of crystallization precursors to be monitored quantitatively as the level of nominal (super)saturation gradually increases. The nature and spatiotemporal evolution of these precursors was further elucidated by time‐resolved small‐angle X‐ray scattering (SAXS) and analytical ultracentrifugation (AUC) experiments, complemented by cryogenic transmission electron microscopy (cryo‐TEM) as a direct imaging technique. The results reveal how ions associate into nanometric primary species, which subsequently aggregate and develop anisotropic order by intrinsic structural reorganization. Our observations challenge the common understanding of fundamental notions such as the nucleation barrier or the meaning of supersaturation, with broad implications for mineralization phenomena in general and the formation of calcium sulfate in geochemical settings and industrial applications in particular.
KW - Calcium sulfate
KW - Gypsum
KW - Nucleation
KW - Crystallisation
PY - 2024
DO - https://doi.org/10.1002/anie.202408429
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-61585
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schultheiß, Annika L.
A1 - Kruschwitz, Sabine
A1 - Wilsch, Gerd
A1 - Bogner, Andreas
A1 - Patel, Ravi
T1 - Lessons learnt on quantiative spatial chloride analysis using libs and µXRF
N2 - Understanding chloride ingress is crucial in the context of the durability of concrete structures against corrosion. Techniques such as Laser-Induced Breakdown Spectroscopy (LIBS) and Micro X‑ray Fluorescence (µXRF) can provide a 2D representation of chloride ingress. However, obtaining quantitative data from such techniques is not a trivial task. In this study, we focus on factors such as sample preparation, measurement settings, calibration strategy, and post-processing of results which directly affect the outcome of the experiments but are rarely discussed in the literature.
T2 - Rilem Annual Week 2024
CY - Toulouse, Frankreich
DA - 25.08.2024
KW - Durability
KW - Chloride ingress
KW - LIBS
KW - µXRF
KW - Nondestructive testing
KW - Imaging
PY - 2024
SP - 1
EP - 9
AN - OPUS4-61664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cios, G.
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Jany, B. R.
A1 - Bala, P.
T1 - EBSD and TKD analyses using inverted contrast Kikuchi diffraction patterns and alternative measurement geometries
N2 - Electron backscatter diffraction (EBSD) patterns can exhibit Kikuchi bands with inverted contrast due to anomalous absorption. This can be observed, for example, on samples with nanoscale topography, in case of a low tilt backscattering geometry, or for transmission Kikuchi diffraction (TKD) on thicker samples. Three examples are discussed where contrast-inverted physics-based simulated master patterns have been applied to find the correct crystal orientation. As first EBSD example, self-assembled gold nanostructures made of Au fcc and Au hcp phases on single-crystal germanium were investigated. Gold covered about 12% of the mapped area, with only two thirds being successfully interpreted using standard Hough-based indexing. The remaining third was solved by brute force indexing using a contrast-inverted master pattern. The second EBSD example deals with maps collected at a non-tilted surface instead of the commonly used 70◦ tilted one. As TKD example, a jet-polished foil made of duplex stainless steel 2205 was examined. The thin part close to the hole edge producing normal-contrast patterns were standard indexed. The areas of the foil that become thicker with increasing distance from the edge of the hole produce contrast-inverted patterns. They covered three times the evaluable area and were successfully processed using the contrast-inverted master pattern. In the last example, inverted patterns collected at a non-tiled sample were mathematically inverted to normal contrast, and Hough/Radon-based indexing was successfully applied.
KW - EBSD
KW - TKD
KW - Contrast inversion
KW - Topography
KW - Kikuchi diffraction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613862
VL - 267
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weichert, Dorina
A1 - Kister, Alexander
A1 - Houben, Sebastian
A1 - Link, Patrick
A1 - Ernis, Gunar
ED - Kiyavash, Negar
ED - Mooij, Joris M.
T1 - Robust Entropy Search for Safe Efficient Bayesian Optimization
N2 - The practical use of Bayesian Optimization (BO) in engineering applications imposes special requirements: high sampling efficiency on the one hand and finding a robust solution on the other hand. We address the case of adversarial robustness, where all parameters are controllable during the optimization process, but a subset of them is uncontrollable or even adversely perturbed at the time of application. To this end, we develop an efficient information-based acquisition function that we call Robust Entropy Search (RES). We empirically demonstrate its benefits in experiments on synthetic and real-life data. The results show that RES reliably finds robust optima, outperforming state-of-the-art algorithms.
T2 - UAI 2024
CY - Barcelona, Spain
DA - 15.07.2024
KW - Bayesian Optimization
KW - Gaussian process
KW - Active learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613523
UR - https://proceedings.mlr.press/v244/weichert24a.html
SN - 2640-3498
VL - 244
SP - 3711
EP - 3729
PB - Proceedings of Machine Learning Research
AN - OPUS4-61352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Digitale Qualitätssicherung in der Additiven Fertigung
N2 - Der Vortrag stellt das Pilotprojekt Additive Fertigung innerhalb von QI Digital vor und zeigt bisher Erreichtes. Dies umfasst eine digital durchgängige Baujobvorbereitung, automatisierte Datenerhebung und -registrierung sowie die Einbindung des Prozessmonitorings. Seitens der PTB wird ein digitaler Prüfbericht vorgestellt.
T2 - QI Forum 2024
CY - Berlin, Germany
DA - 09.10.2024
KW - Additive Fertigung
KW - Digitale Qualitätssicherung
KW - QI Digital
PY - 2024
AN - OPUS4-61361
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Hygienische Bewertung von SLM-gedrucktem rostfreiem Stahl
N2 - Werkstoffe im Kontakt mit Trinkwasser müssen hygienisch bewertet werden. Hier wird ein bereits bewerteter Werkstoff wegen neuer Fertigungsmethoden (additive Fertigung) erneut geprüft und die Besonderheiten durch das Verfahren dargestellt. Der Werkstoff ist auch mit additiver Produktionsmethode geeignet.
T2 - GfKORR - Jahrestagung
CY - Frankfurt am Main, Germany
DA - 05.11.2024
KW - Additive Fertigung
KW - Trinkwasser
KW - Korrosion
KW - Nichtrostender Stahl
PY - 2024
AN - OPUS4-61845
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bruns, Sebastian
A1 - Bayerlein, Bernd
A1 - Kryeziu, Jehona
A1 - Schaarschmidt, Jörg
A1 - Waitelonis, Jörg
A1 - Dolabella Portella, Pedro
A1 - Durst, Karsten
T1 - Seamless Science: Lifting Experimental Mechanical Testing Lab Data to an Interoperable Semantic Representation
N2 - The scientific landscape is undergoing rapid transformations with the advent of the digital age which revolutionizes research methodologies. In materials science and engineering, an adoption of modern data management techniques is desirable to maximize the efficiency and accessibility of research efforts. Traditional practices in testing laboratories are usually inadequate for efficient data acquisition and utilization as they lead to local storage and difficulty in publication and correlation with other results. Electronic laboratory notebooks (ELNs) are promising prospects in this respect. Semantic concepts and ontologies enhance interoperability by standardizing experimental data representation. An in‐laboratory pipeline seamlessly integrating an ELN with transformation scripts to convert experimental into interoperable data in a machine‐actionable format is created in this study as a proof of concept. Tensile test results and the corresponding tensile test ontology are used exemplary. Linking ELN data to semantic concepts enriches the stored information while improving interpretability and reusability. Involving undergraduate students builds a bridge between theory and practice during their training and promotes their digital skills. This study underscores the potential of ELNs and knowledge representations as beneficial means toward improved data management practices that enhance collaborative research and education while ensuring compatibility with evolving standards and technologies.
KW - Semantic Data
KW - Data Integration
KW - Tensile Test Ontology
KW - Electronic Lab Notebook
KW - Wissensrepräsentation
KW - Education
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618251
DO - https://doi.org/10.1002/adem.202401527
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-61825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Interoperabilität und Wiederverwendung von Materialdaten: Der Weg zu Daten- und Wissensrepräsentationen in der PMD
N2 - Die Integration und Wiederverwendung von Wissen und Daten aus der Herstellung, Bearbeitung und Charakterisierung von Materialien wird im Zuge der digitalen Transformation in der Materialwissenschaft und Werkstofftechnologie in verschiedenen Projekten behandelt. Dabei liegt der Fokus auf der Interoperabilität von Daten und Anwendungen, die nach den FAIR-Prinzipien erstellt und veröffentlicht werden. Zur Umsetzung eines komplexen Datenmanagements und der Digitalisierung im Bereich der Materialwissenschaften gewinnen Ontologien zunehmend an Bedeutung. Sie ermöglichen sowohl menschenlesbare als auch maschinenverständliche und -interpretierbare Wissensrepräsentationen durch semantische Konzeptualisierungen.
Im Rahmen des Projektes Plattform MaterialDigital (PMD, materialdigital.de), welches in dieser Präsentation vorgestellt wird, werden Ontologien verschiedener Ebenen entwickelt (verbindende mid-level sowie Domänen-Ontologien). Die PMD-Kernontologie (PMD Core Ontology - PMDco) ist eine Ontologie der mittleren Ebene, die Verbindungen zwischen spezifischeren MSE-Anwendungsontologien und domänenneutralen Konzepten herstellt, die in bereits etablierten Ontologien höherer Ebenen (top-level Ontology) verwendet werden. Sie stellt somit einen umfassenden Satz von durch Konsensbildung in der Gemeinschaft (geteiltes Vokabular) entstanden Bausteinen grundlegender Konzepte aus der Materialwissenschaft und Werkstofftechnik (MSE) dar. In dieser Präsentation wird die PMDco adressiert.
Weiterhin wird eine auf die PMDco bezogene normenkonforme ontologische Repräsentation zur Speicherung und Weiterverarbeitung von Zugversuchsdaten – die Tensile Test Ontology (TTO) – präsentiert, die in enger Zusammenarbeit mit dem zugehörigen DIN-Standardisierungsgremium NA 062-01-42 AA erstellt wurde. Dies umfasst den Weg von der Entwicklung einer Ontologie nach Norm, der Konvertierung von Daten aus Standardtests in das interoperable RDF-Format bis hin zur Verbindung von Ontologie und Daten. Auf Grundlage der dabei entwickelten Struktur und Vorgehensweise können weitere Materialcharakterisierungsmethoden semantisch beschrieben werden, woraus sich in diesem Zusammenhang Kooperationsmöglichkeiten ergeben.
T2 - 20. Sitzung des NA 062-01-43 AA
CY - Online meeting
DA - 28.05.2024
KW - Semantische Daten
KW - Plattform Material Digital
KW - Ontologie
KW - Normung
KW - Wissensrepräsentation
PY - 2024
AN - OPUS4-60178
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavasarytė, Lina
A1 - Azevedo do Nascimento, Allana
A1 - Cysne Barbosa, Ana Paula
A1 - Trappe, Volker
A1 - Melo, Daniel
T1 - Effects of particle size and particle concentration of poly (ethylene-co-methacrylic acid) on properties of epoxy resin
N2 - Self-healing polymers have been developed to improve durability and reduce costs associated with maintenance during service. The addition of thermoplastics to thermosets to produce mendable polymers appears as a promising selfhealing technique. In this study, poly (ethylene-co-methacrylic acid) (EMAA) was added to epoxy resin and the effects of EMAA addition on epoxy properties were evaluated. Specimens with two different contents of thermoplastic and particles sizes were manufactured. A two-level full factorial experimental design was used to evaluate the effect of particle size and particle content on properties of epoxy modified with addition of EMAA. Tensile tests and dynamic mechanical analysis (DMA) were used and the evaluated responses were tensile strength, modulus of elasticity, and glass transition temperature (Tg). X-ray computed tomography (XCT) was used to investigate particle size and concentration after manufacturing. It was found that the particle concentration has greater effects on stress–strain behavior of epoxy while Tg was not significantly affected by neither of the analyzed entrance variables.
KW - Fracture
KW - Self-healing
KW - Epoxy
KW - Thermoplastic
PY - 2024
DO - https://doi.org/10.1002/app.55677
SN - 0021-8995
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-60205
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Digital Transformation in Materials Science: Insights from Platform MaterialDigital (PMD), Tensile Test Ontology (TTO), Electronic Lab Notebooks (ELN)
N2 - The digital era has led to a significant increase in innovation in scientific research across diverse fields and sectors. Evolution of data-driven methodologies lead to a number of paradigm shifts how data, information, and knowledge is produced, understood, and analyzed. High profile paradigm shifts in the field of materials science (MS) include exploitative usage of computational tools, machine learning algorithms, and high-performance computing, which unlock novel avenues for investigating materials. In these presentations, we highlight prototype solutions developed in the context of the Platform MaterialDigital (PMD) project that addresses digitalization challenges. As part of the Material Digital Initiative, the PMD supports the establishment of a virtual materials data space and a systematic handling of hierarchical processes and materials data using a developed ontological framework as high priority work items. In particular, the mid-level ontology PMDco and its augmentation through application-specific ontologies are illustrated. As part of the conclusion, a discussion encompasses the evolutionary path of the ontological framework, taking into account standardization efforts and the integration of modern AI methodologies such as natural language processing (NLP). Moreover, demonstrators illustrated in these presentations highlight: The integration and interconnection of tools, such as digital workflows and ontologies, Semantic integration of diverse data as proof of concept for semantic interoperability, Improved reproducibility in image processing and analysis, and Seamless data acquisition pipelines supported by an ontological framework. In this context, concepts regarding the application of modern research data management tools, such as electronic laboratory notebooks (ELN) and laboratory information management systems (LIMS), are presented and elaborated on. Furthermore, the growing relevance of a standardized adoption of such technologies in the future landscape of digital initiatives is addressed. This is supposed to provide an additional basis for discussion with respect to possible collaborations.
T2 - NIST Seminar Series
CY - Gaithersburg, MD, USA
DA - 11.06.2024
KW - Semantic Data
KW - Plattform Material Digital
KW - Digitalization
KW - Data Interoperability
KW - NIST
KW - Tensile Test Ontology
KW - Elctronic Lab Notebook
PY - 2024
AN - OPUS4-60392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nag, Sayak
A1 - Emmerling, Franziska
A1 - Tothadi, Srinu
A1 - Bhattacharya, Biswajit
A1 - Ghosh, Soumyajit
T1 - Distinct photomechanical responses of two new 1,3-dimethylbarbituric acid derivative crystals
N2 - We demonstrate two distinct photomechanical responses (i.e. photomechanical bending and photosalient bursting) of two new 1,3-dimethylbarbituric acid derivative crystals based on tailoring their substituents and the modulation of their spacers.
KW - Crystal engineering
KW - Fexible crystals
PY - 2024
DO - https://doi.org/10.1039/D4CE00233D
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poka, Konstantin
A1 - Ali, Sozol
A1 - Saeed, Waleed
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Design and implementation of a machine log for PBF-LB/M on basis of IoT communication architectures and an ETL pipeline
N2 - AbstractPowder Bed Fusion with Laser Beam of Metals (PBF-LB/M) has gained more industrial relevance and already demonstrated applications at a small series scale. However, its widespread adoption in various use cases faces challenges due to the absence of interfaces to established Manufacturing Execution Systems (MES) that support customers in the predominantly data-driven quality assurance. Current state-of-the-art PBF-LB/M machines utilize communication architectures, such as OPC Unified Architecture (OPC UA), Message Queuing Telemetry Transport (MQTT) and Representational State Transfer Application Programming Interface (REST API). In the context of the Reference Architecture Model Industry 4.0 (RAMI 4.0) and the Internet of Things (IoT), the assets, particularly the physical PBF-LB/M machines, already have an integration layer implemented to communicate data such as process states or sensor values. Missing is an MES component acting as a communication and information layer. To address this gap, the proposed Extract Transform Load (ETL) pipeline aims to extract relevant data from the fabrication of each build cycle down to the level of scan vectors and additionally to register process signals. The suggested data schema for archiving each build cycle adheres to all terms defined by ISO/TC 261—Additive Manufacturing (AM). In relation to the measurement frequency, all data are reorganized into entities, such as the AM machine, build cycle, part, layer, and scan vector. These scan vectors are stored in a runtime-independent format, including all metadata, to be valid and traceable. The resulting machine log represents a comprehensive documentation of each build cycle, enabling data-driven quality assurance at process level.
KW - FAIR data
KW - Data-driven quality assurance
KW - Laser powder bed fusion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601256
DO - https://doi.org/10.1007/s40964-024-00660-7
SN - 2363-9512
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-60125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Structure-property correlations in RE-doped fluoride-phosphate glasses sought by NMR, EPR & PL
N2 - As the development of optimized glass compositions by traditional trial-and-error methods is laborious, expensive, and time consuming, it is desirable to gather fundamental understanding of structure and to develop structure-property relation models, which allow best and faster choices. Particularly, when it comes to optical applications of glasses doped with emissive trivalent rare earth ions (RE), the chemical environmental around the ions will have a direct influence on the radiative/non-radiative emission probabilities. The vibrational environment and the chemical nature of the bonds in the first coordination sphere of the ions can be tailored, to some extent, based on structural information given by magnetic resonance (NMR and EPR) techniques associated to Raman and photophysical characterization. For the past 5 years, one of the interests of my research group at the University of São Paulo, in Brazil, has been the development of high-density fluoride-phosphate glasses as promising UV and X-ray scintillator materials. The targeted glasses offer a lower vibrational energy, less hygroscopic fluoride environment for the RE ions whereas the phosphate network provides improved mechanical and chemical stability than a purely fluoride glass matrix. Different sets of glasses, based on the compositional system (Ba/Sr)F2-M(PO3)3-MF3-(Sc/Y)F3 where M = Al, In, Ga, and the phosphate component is substituted by the fluoride analogue in 10-30 mol%, were investigated, using Sc3+, Y3+, and the Eu3+ and Yb3+ dopants, as structural probes. Overall, results show that the desired RE coordination by F, at a given F/P ratio, is proportional to the atomic mass of M (In> Ga> Al) and that the Ga- and In- based systems differ from the Al- one by near absence of P-O-P network linkages i.e, the network structures are dominated by Ga-O-P or In-O-P linkages as evidenced by 31P MAS-NMR and Raman. These results are nicely corroborated by observation of decreased intensity in the vibronic band of Eu3+ and significant increase in the excited state lifetime values. Radioluminescence studies were carried out for a series of In-based glasses doped with Ce3+ and Tb3+ yielding intense emissions in the blue and green, respectively, compatible to the spectral region of highest sensitivity of radiation sensor detectors. The aim of the presentation is to show how powerful the combination of NMR, EPR, Raman and PLE spectroscopies can be to provide structural information and to present the perspectives for their introduction in the research agenda of Division 5.6 – Glass, which I now lead, at the Federal Institute for Materials Research and Testing (BAM) in Berlin, Germany.
T2 - GOMD 2024 - Glass and Optical Division Meeting, ACerS
CY - Las Vegas, NV, USA
DA - 19.05.2024
KW - Glass Digital
KW - Glasses
KW - Robotic melting
PY - 2024
AN - OPUS4-60357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Galleani, Gustavo
A1 - Lodi, Thiago A.
A1 - Conner, Robin L.
A1 - Jacobsohn, Luiz G.
A1 - de Camargo, Andrea Simone Stucchi
T1 - Photoluminescence and X-ray induced scintillation in Gd3+-Tb3+ co-doped fluoride-phosphate glasses, and derived glass-ceramics containing NaGdF4 nanocrystals
N2 - The glass system (50NaPO3–20BaF2–10CaF2–20GdF3)-xTbCl3 with x = 0.3, 1, 3, 5, and 10 wt % was investigated. We successfully produced transparent glass ceramic (GC) scintillators with x = 1 through a melt-quenching process followed by thermal treatment. The luminescence and crystallization characteristics of these materials were thoroughly examined using various analytical methods. The nanocrystallization of Tb3+-doped Na5Gd9F32 within the doped fluoride-phosphate glasses resulted in enhanced photoluminescence (PL) and radioluminescence (RL) of the Tb3+ ions. The GC exhibited an internal PL quantum yield of 33 % and the integrated RL intensity across the UV-visible range was 36 % of that reported for the commercial BGO powder scintillator. This research showcases that Tb-doped fluoridephosphate GCs containing nanocrystalline Na5Gd9F32 have the potential to serve as efficient scintillators while having lower melting temperature compared to traditional silicate and germanate glasses.
KW - Glass scintillator
KW - Fluoride phosphate glasses
KW - Gd3+
KW - Tb3+
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603588
DO - https://doi.org/10.1016/j.omx.2023.100288
VL - 21
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-60358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Structure-property correlations in RE-doped fluoride-phosphate glasses for scintillation
N2 - As the development of optimized glass compositions by traditional trial-and-error methods is laborious, time consuming, and expensive, it is desirable to develop glass compositions based on a fundamental understanding of the glass structure and to establish structure-property relation models. Particularly, when it comes to optical applications of glasses doped with emissive trivalent rare earth ions (RE), the chemical environmental around the ions will have a direct influence on the radiative/non-radiative emission probabilities. The local vibrational environment and the chemical nature of the bonds in the first coordination sphere of the ions can be tailored, to good extent, based on structural information given by magnetic resonance techniques (NMR and EPR), associated to Raman and photophysical characterization. For the past 5 years, while still employed at the University of São Paulo, in Brazil, one of the interests of my research group has been the development of high-density fluoride-phosphate glasses as promising UV and X-ray scintillator materials. The targeted glasses offer a lower vibrational energy, less hygroscopic fluoride environment for the RE ions whereas the phosphate network provides better mechanical and chemical stability than a purely fluoride glass matrix. Different sets of glasses, based on the compositional system (Ba/Sr)F2-M(PO3)3-MF3-(Sc/Y)F3 where M = Al, In, Ga, and the phosphate component is substituted by the fluoride analogue in 10 - 30 mol%, were investigated, using Sc3+, Y3+, and the Eu3+ and Yb3+ dopants, as structural probes. Overall, results show that the desired RE coordination by fluorine, at a given F/P ratio, is proportional to the atomic mass of M (In> Ga> Al) and that the Ga- and In- based systems differ from the Al- one by near absence of P-O-P network linkages. That is, the network structures are dominated by Ga-O-P or In-O-P linkages, as evidenced by 31P MAS-NMR and Raman. These results are nicely corroborated by observation of decreased intensity of the vibronic band in Eu3+-doped glasses and marked increase in excited state lifetime values. Radioluminescence studies were carried out for a series of In-based glasses doped with Ce3+ and Tb3+, yielding intense emissions in the blue and green, respectively, compatible to the spectral region of the highest sensitivity of radiation sensor detectors. The aim of the presentation is to show how powerful the NMR and EPR techniques can be to provide decisive structural information, and to present the research perspectives in my new role as the Head of Division 5.6 – Glass at BAM.
T2 - Fachausschusses I „Physik und Chemie des Glases“, DGG
CY - Jena, Germany
DA - 02.11.2023
KW - Structure-property correlation
KW - Fluoride phosphate glasses
KW - Scintillators
KW - High energy radiation
PY - 2024
AN - OPUS4-60360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schob, Daniela
T1 - Comparative Analysis FFF vs. cold rolled 316L Samples
N2 - This study provides insights into the properties of 316L stainless steel produced by additive manufacturing using fused filament fabrication (FFF). One key finding is particularly noteworthy: in significant contrast to cold-rolled 316L, FFF316L develops a pronounced martensite phase after fabrication. The comprehensive comparative analysis shows that FFF316L not only retains the ferrite volume content, but that this is also significantly influenced by the build-up direction. Despite the sintering process, which typically involves densification of the material, a pore volume fraction of 8.45 % remains, which influences the mechanical properties. Although FFF316L has lower elastic
modulus and tensile strength values compared to cold-rolled 316L, its ductility is still competitive. The study further reveals that deformation-induced martensite forms at the intersections of the deformation twins and ferrite islands form at the grain boundaries during the compression and sintering phases. These findings highlight the challenges associated with FFF316L in specific application fields and signal the need to continue to carefully evaluate and improve the development of manufacturing technologies.
T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024
CY - Berlin, Germany
DA - 12.06.2024
KW - Additive manufacturing
KW - Fused Filament Fabrication
KW - Computed Tomography
KW - 316L Stainless Steel
KW - Deformation-Induced Martensite
PY - 2024
AN - OPUS4-60302
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Galleani, Gustavo
A1 - Lodi, Thiago
A1 - Merízio, Leonnam
A1 - de Jesus, Vinícius
A1 - de Camargo, Andrea Simone Stucchi
T1 - Scintillators, persistent luminescent and white light emitters: Progresses on UV and X-ray converting glasses and composites
N2 - Recently, detection and conversion of high energy radiation such as ultraviolet and X-rays has gained renewed attention. In part, technological applications in radioimaging and tomography have developed considerably as to allow lower dosages and higher resolutions, which require optimized scintillators and dosimeters. On the other hand, the increasing effort to reduce carbon footprint in energy production has triggered an intensive search for materials that can be excited with sunlight, ranging from photocatalysts to solar concentrators. At LEMAF – Laboratory of Spectroscopy of Functional Materials at IFSC/USP, we have been developing bulk glasses, polycrystalline and composite materials designed to target both challenges and, in this work an overview of recent progresses and of the state of art of these materials will be given.
For instance, the few available comercial scintillators are crystalline materials with costly and time consuming growth which hinders the development of new compositions. Glasses and glass ceramics, such as the NaPGaW composition developed in our lab, present high density, very good optical properties and high chemical stability which allow them radioluminescent response when doped with low concentrations of Ce3+, Eu3+ and Tb3+ offering a promise as alternatives to crystal scintillators. On the other hand, phosphor in glass (PiG) composites based on the persistent luminescent polycrystalline material Sr2MgSi2O7:Eu2+,Dy3+ (SMSO) embedded into NaPGa glasses offer interesting perspectives for the of UV light into visible, useful for white light generation (lighting), improved harvesting and conversion of solar light when coupled to c-Si PV cells and photocatalysis. These and other examples will be discussed.
The glasses are prepared through the conventional melt quenching technique, followed by controlled heating when glass ceramics are desired. The persistent luminescent phosphor is prepared by the microwave assisted technique (MAS) much faster and with considerable energy consumption reduction than in the usual solid state synthesis. The materials are characterized from the structural, morphological and spectroscopic (optical – UV-Vis, PL, PLE, and structural – NMR, EPR) points of view such that structure-property correlations are constantly sought to feedback synthesis and processing. Fig. 1, illustrates two examples of scintillator glasses doped with Tb3+ and PiG composites doped with Eu2+ and Dy3+.
T2 - 11th International Conference on f Elements (ICFE-11)
CY - Strasbourg, France
DA - 22.08.2023
KW - Scintillators
KW - Persistent luminescence
KW - White light emitters
PY - 2023
AN - OPUS4-60361
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Optical properties of dental ceramics: Characterization via UV-Vis and photoluminescence spectroscopies
N2 - When it comes to dental treatments, success is not only measured by attained functionality but, to a large extent, the associated aesthetics. This can become challenging for certain restorations and implants due to the complex optical characteristic of a tooth, which reflects, absorbs, diffuses, transmits, and even emits light. Thus, to get acceptable aesthetic results, favourable shade matching of ceramic restorations and implants should be achieved by strict control of optical response, which translates into a materials design question. Optical response is affected by several factors such as the composition, crystalline content, porosity, additives, grain size and the angle of incidence of light on the dental ceramics. The properties to be characterized are colour (and its stability), translucency, opalescence, refractive index, and fluorescence. Several techniques can be applied for the characterization of these properties and in this presentation, an overview will be given. Moreover, particular emphasis will be given on the capacitation of less familiarized public to UV-Vis absorption and photoluminescence (PLE) spectroscopies that are versatile and widely employed for functional and structural characterization of glasses and glass ceramic materials.
T2 - 2nd BAYLAT Workshop of CERTEV - FAU
CY - Nuremberg, Germany
DA - 04.12.2023
KW - Optical properties
KW - Dental ceramics
KW - Optical spectroscopy
PY - 2023
AN - OPUS4-60364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Glass Digitalization: Contributions from BAM
N2 - An overview of the Glass Digitalization efforts at BAM, within the framework of the Glass Digital consortium, was given. From the development of the robotic melting device to the ML capabilities, a description of the different stages of the developments and roles of project partner was presented.
T2 - GlaCerHub Melting Day
CY - Oponice, Slovakia
DA - 12.06.2024
KW - Glass Digital
KW - Robotic glass melting
KW - Digitalization
PY - 2024
AN - OPUS4-60365
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Gender equality in Sciences: Let´s teach our girls to be brave!
N2 - A panorama of the global gender gap scenario in sciences, specially STEM, was given to illustrate the need for urgent actions (and suggestions of them) to correct biased treatment and promote females in their scientific careers.
T2 - FunGlass School
CY - Oponice, Slovakia
DA - 10.06.2024
KW - Gender gap
KW - Women in science
KW - Female noble prize winners
PY - 2024
AN - OPUS4-60366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Spectroscopy Lectures
N2 - As a guest professor of FUNGLASS, I delivered 3 lectures on spectroscopy to the Graduate School Program, the postdoctoral fellows and other researchers: 1) Introduction to spectroscopy applied to solid state materials (with focus on glass and glass ceramics); 2) Vibrational spectroscopy (Infrared and Raman); 3) Electron Paramagnetic Resonance
T2 - FunGlass
CY - Trencín, Slovakia
DA - 03.06.2024
KW - Spectroscopy
KW - Radiation-matter interaction
KW - FT-IR
KW - Raman
KW - EPR
PY - 2024
AN - OPUS4-60367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - From guest scintillators to luminescent host-guest hybrid materials and nanoparticles: Contributions from LEMAF
N2 - An overview of the research work conducted at LEMAF - the laboratory of spectroscopy of functional materials in IFSC/USP Brazil under my leadership, before I joined BAM was given.
T2 - FunGlass Graduate Program School
CY - Oponice, Slovakia
DA - 10.10.2023
KW - Multifunctional nanoparticles
KW - Structure property correlations
KW - Host-guest hybrid materials
KW - Scintillators
KW - Persistent luminescent
KW - Phosphors
KW - Composite materials
PY - 2024
AN - OPUS4-60368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Gender equality in sciences: Let's teach our girls to be brave!
N2 - A global panorama of the Gender Gap in Sciences was presented along with recommendations on how to remediate unequal treatment of females in Science, and to prepare future generations for gender equality.
T2 - Lunch Talk - Women@DGM: Gender Mindsets/Bias in an International Context
CY - Online meeting
DA - 14.06.2024
KW - Gender gap
PY - 2024
AN - OPUS4-60369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Optical properties of glasses and ceramics
N2 - Optical glasses and glass ceramics are present in many devices often used in our daily routine, such as the mobile phones and tablets. Since the 1960´s with the development of glass lasers, and more recently, within the search for efficient W-LEDs, sensors and solar converters, this class of materials has experienced extreme research progress. In order to tailor a material for such applications, it is very important to understand and characterize optical properties such as refractive index, transmission window, absorption and emission cross sections, quantum yields, etc. These properties can often be tuned by appropriate compositional choice and post-synthesis processing. In this lecture we will discuss the optical properties of glasses and glass ceramics, relevant to that end.
T2 - 2nd CeRTEV Glass School
CY - São Carlos, SP, Brazil
DA - 22.04.2024
KW - Optical properties of glasses and ceramics
PY - 2024
AN - OPUS4-60370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - PMD core ontology: Building Bridges at the Mid-Level – A Community Effort for Achieving Semantic Interoperability in Materials Science
N2 - Knowledge representation in the materials science and engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant and variant knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific.
This poster presents an approach to create and maintain a comprehensive and intuitive MSE-centric terminology by developing a mid-level ontology–the PMD core ontology (PMDco)–via MSE community-based curation procedures.
The PMDco is designed in direct support of the FAIR principles to address immediate needs of the global experts community and their requirements. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics, how the PMDco lowers development and integration thresholds, and how to fuel it from real-world data sources ranging from manually conducted experiments and simulations as well as continuously automated industrial applications.
T2 - TMS - Specialty Congress 2024
CY - Cleveland, Ohio, US
DA - 16.06.2024
KW - Interoperability
KW - Semantic Interoperability
KW - Digtial Representation
KW - Knowledge graph and ontologies
PY - 2024
AN - OPUS4-60378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Digital Transformation in Materials Science: Insights From the Platform MaterialDigital (PMD)
N2 - The digital era has led to a significant increase in innovation in scientific research across diverse fields and sectors. Evolution of data-driven methodologies lead to a number of paradigm shifts how data, information, and knowledge is produced, understood, and analyzed. High profile paradigm shifts in the field of materials science (MS) include exploitative usage of computational tools, machine learning algorithms, and high-performance computing, which unlock novel avenues for investigating materials. In these presentations, we highlight prototype solutions developed in the context of the Platform MaterialDigital (PMD) project that addresses digitalization challenges. As part of the Material Digital Initiative, the PMD supports the establishment of a virtual materials data space and a systematic handling of hierarchical processes and materials data using a developed ontological framework as high priority work items. In particular, the mid-level ontology PMDco and its augmentation through application-specific ontologies are illustrated. As part of the conclusion, a discussion encompasses the evolutionary path of the ontological framework, taking into account standardization efforts and the integration of modern AI methodologies such as natural language processing (NLP). Moreover, demonstrators illustrated in these presentations highlight: The integration and interconnection of tools, such as digital workflows and ontologies, Semantic integration of diverse data as proof of concept for semantic interoperability, Improved reproducibility in image processing and analysis, and Seamless data acquisition pipelines supported by an ontological framework. In this context, concepts regarding the application of modern research data management tools, such as electronic laboratory notebooks (ELN) and laboratory information management systems (LIMS), are presented and elaborated on. Furthermore, the growing relevance of a standardized adoption of such technologies in the future landscape of digital initiatives is addressed. This is supposed to provide an additional basis for discussion with respect to possible collaborations.
T2 - NIST Seminar on Digital Transformation
CY - Gaithersburg, MD, USA
DA - 11.06.2024
KW - Digital Transformation
KW - Research Data Management
KW - Ontology
KW - Reusability
KW - FAIR
PY - 2024
AN - OPUS4-60381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vollmer, Malte
A1 - Degener, Sebastian
A1 - Bolender, Artjom
A1 - Bauer, Andre
A1 - Liehr, Alexander
A1 - Stark, Andreas
A1 - Schell, Norbert
A1 - Barriobero-Vila, Pere
A1 - Requena, Guillermo
A1 - Niendorf, Thomas
T1 - Time resolved insights into abnormal grain growth by in situ synchrotron measurements
N2 - Large oligo-crystalline or single-crystalline metallic materials are of great interest for numerous applications, and a recently developed strategy for promoting abnormal grain growth induced by a cyclic heat treatment opens up new opportunities to manufacture single crystals with a size of several centimeters. So far, the entire available knowledge on this kind of abnormal grain growth has been elaborated based on time discrete observations and, thus, detailed insights into the interplay of elementary mechanisms are still lacking in open literature. The present study reveals time resolved insights into this kind of abnormal grain growth for the first time. It was possible to break down the influence of the individual heat treatment phases by in situ synchrotron high energy X-ray diffraction analysis during cyclic heat reatment. The results obtained not only help to gain a deep understanding of the abnormal grain growth mechanisms, they will also be the basis for an adjustment of the cyclic heat treatment process to improve its efficiency and to eventually obtain even larger single crystals.
KW - Single crystals
KW - Grain growth method
KW - Synchrotron diffraction
KW - High-energy X-ray diffraction
KW - Grain boundary migration
PY - 2023
DO - https://doi.org/10.1016/j.actamat.2023.119168
SN - 1359-6454
VL - 257
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-62188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fink, Friedrich
T1 - From Bench to Mini – Identification of technical Lignins with NIR
N2 - One of the most underutilized biological materials on our planet is lignin. It is the second most abundant biopolymer after cellulose. On an industrial scale, it mainly accumulates as a by-product in the pulp and paper industry. However, the utilization of technical lignins faces several challenges, including their complex and heterogeneous structure, which makes them difficult to process and limits their application. Additionally, the feedstock origin is a limiting factor. Classification according to the biomass origin is important for quality assurance and predictability of potential applications.
In this study, technical lignins were analyzed using a near-infrared (NIR) spectrometer. Different models were developed to classify these lignins, enabling rapid and reliable identification of their biomass sources, including softwoods, hardwoods, straw, and grasses. Various machine learning algorithms such as Support Vector Machines (SVM), Gaussian Process Classification (GPC), Gaussian Naive Bayes (GNB), and Decision Tree Classification (DTC) were compared based on different spectral preprocessing techniques and dimensionality reduction tools. The efficacy of the method was further tested using combined spectra from small handheld and compact spectrometers.
T2 - ESOPS 2024
CY - Berlin, Germany
DA - 09.09.2024
KW - NIR
KW - Lignin
PY - 2024
AN - OPUS4-62275
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Taketa, I.
A1 - Kalinka, Gerhard
A1 - Gorbatikh, L.
A1 - Lomov, S.
A1 - Verpoest, I.
T1 - Influence of cooling rate on the properties of carbon fiber unidirectional composites with polypropylene, polyamide 6, and polyphenylene sulfide matrices
N2 - The longitudinal and transverse strength of three unidirectional thermoplastic prepreg systems: carbon fiber/polypropylene (CF/PP), polyamide 6 (CF/PA6), and polyphenylene sulfide (CF/PPS) are studied and analytical formulas are proposed for the estimation of matrix and fiber/matrix interface properties from composites properties. Since the matrices are semi-crystalline thermoplastics, the influence of cooling rate on the strength is statistically evaluated. While the 0° tensile strength is found to be independent of the cooling rate, the 90° tensile strength is strongly influenced by the matrix type and cooling rate. The matrix modulus increases as the cooling rate is decreased; the degree of crystallinity also increases. The matrix residual stress, interfacial shear strength, and mode II interlaminar fracture toughness are also found to depend on the cooling rate, with the trends different for different matrices.
KW - Matrix residual stress
KW - Thermoplastic prepreg
KW - Unidirectional composites
KW - Cooling rate
KW - Interfacial strength
PY - 2020
DO - https://doi.org/10.1080/09243046.2019.1651083
SN - 0924-3046
SN - 1568-5519
N1 - Die originale japanische Version des Artikels erschien in: Journal of the Japan Society for Composite Materials, Jg. 44, Nr. 4 (2018), S. 123-128. - The original Japanese version of the article was published in: Journal of the Japan Society for Composite Materials, vol. 44, no. 4 (2018), pp. 123-128.
VL - 29
IS - 1
SP - 101
EP - 113
PB - Taylor & Francis
CY - London
AN - OPUS4-45433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tabin, Jakub
T1 - Deformation-Induced Martensitic Transformation In Fused Filament Fabricated Austenitic Stainless Steels During Tension At Wide Range Of Temperatures. Part 1: Experimental Results
N2 - Structural components of superconducting magnets (e.g., collars, bladders, or keys) with complex shapes, operating at cryogenic temperatures (4K, 77K), as well as additional elements of tanks for storing liquid hydrogen (20K), such as hoses and valves, are made of austenitic steel. It is well known that achieving a complex shape for these elements using traditional machining methods is challenging. A viable solution lies in using additive manufacturing methods (AM), notably the cost-effective Fused Filament Fabrication (FFF) method. The scientific objective of the project is the experimental identification and numerical simulation of the evolution of the deformation-induced martensitic transformation in Fused Filament Fabricated Austenitic Stainless Steel (FFF ASS) 316L at a wide range of temperatures.
We will investigate how deformation-induced phase transformation develops in printed austenitic steels, how the initial state of the sample (e.g., pore distribution) affects it, and whether deformation-induced martensitic transformation influences the rate of damage development, especially at very low temperatures. Does the manufacturing technology of the sample affect the rate of phase transformation or damage development? Finally, but no less important, is whether, as in the case of traditional austenitic steels, the adverse effect of the microdamage field is inhibited by deformation-induced martensitic transformation. Which of these effects dominates in printed austenitic steels and under what conditions? The experimental setup developed in the Institute of Fundamental Technological Research (IPPT PAN) allows for monitoring the evolution of the 3D strain field during the kinematically-controlled tensile tests of macroscopic specimens at 77K. Moreover, the correlation between plastic strain field evolution, martensitic transformation, thermal distributions and acoustic emission will be defined for FFF 316L at 77K and room temperatures. EBSD and EDS investigation of samples pre-strained in uniaxial tensile tests at a wide range of temperatures are also performed.
T2 - 43rd Solid Mechanics Conference
CY - Wroclaw, Poland
DA - 16.09.2024
KW - Deformation-induced martensitic transformation
KW - Austenitic Stainless Steel
KW - Additive Manufacturing
KW - DIC
KW - Cryogenic temperatures
PY - 2024
AN - OPUS4-61187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - Curran, Maurice
A1 - Campbell, Carelyn E.
A1 - Dima, Alden A.
A1 - Birkholz, Henk
A1 - Lau, June W.
T1 - Natural Language Processing-Driven Microscopy Ontology Development
N2 - AbstractThis manuscript describes the accelerated development of an ontology for microscopy in materials science and engineering, leveraging natural language processing (NLP) techniques. Drawing from a comprehensive corpus comprising over 14 k contributions to the Microscopy and Microanalysis conference series, we employed two neural network-based algorithms for NLP. The goal was to semiautomatically create the Microscopy Ontology (MO) that encapsulates and interconnects the terminology most frequently used by the community. The MO, characterized by its interlinked entities and relationships, is designed to enhance the quality of user query results within NexusLIMS. This enhancement is facilitated through the concurrent querying of related terms and the seamless integration of logical connections.
KW - Microscopy Ontology
KW - Knowledge Representation
KW - Semantic Interoperability
KW - Natural Language Processing
KW - Ontology Development
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616942
DO - https://doi.org/10.1007/s40192-024-00378-y
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-61694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - The Dark Side of Science (2024.v2 edition)
N2 - This talk introduces the dark side of science (the ever increasing levels of fraudulent activities in science and scientific publishing). It furthermore explores why the focus on inherently limited metrics drives this phenomenon, and how one can arm themselves against going down this gradient. Tools and tips are presented to enable assessment of other works, and what can be done in general to move away from this.
T2 - Informationsmanagement“ im Master Lebensmitteltechnologie
CY - Berlin, Germany
DA - 26.11.2024
KW - Research fraud
KW - Scientific misconduct
KW - Literature research
KW - Materials science
PY - 2024
AN - OPUS4-61792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pelkner, Matthias
T1 - Vielschichtig: Methoden-Einblick Qualitätssicherung in der additiven Fertigung - Modul 3 Wirbelstromprüfung
N2 - Überblick über die derzeitige Entwicklungen für das Online-Monitoring additiver Fertigungsverfahren für metallische Werkstoffe mittels der Wirbelstromprüfung. Hierbei wird im Kurs eine Einführung in die Wirbelstromprüfung gegeben sowie erste Entwicklungen hinsichtlich eines Online-Monitoring thematisiert.
T2 - BAM Akademie: Vielschichtig: Methoden-Einblick Qualitätssicherung in der additiven Fertigung
CY - Online meeting
DA - 16.10.2024
KW - Wirbelstromprüfung
KW - Additive Fertigung
KW - Prozessüberwachung
PY - 2024
AN - OPUS4-61765
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pelkner, Matthias
T1 - Hochauflösendes WirbelstromPrüfsystem für das Online-Monitoring des PBF-LB/M-Prozesses
N2 - Additive Fertigungstechnologien gewinnen immer mehr an Bedeutung. Für komplexe Funktionsbauteile oder die Produktion von Werkstücken in kleinen Stückzahlen wird häufig das Laser-Pulverbettschmelzen eingesetzt. Hohe Sicherheitsanforderungen, wie etwa in der Luft- und Raumfahrt, machen eine umfassende Qualitätskontrolle unerlässlich. Daher kommen nach der Fertigung zerstörungsfreie „Offline“-Prüfverfahren wie die Computertomographie zum Einsatz. Um die Rentabilität und Praktikabilität zu steigern, wurden jüngst zerstörungsfreie Online-Prüfverfahren wie die optische Tomographie entwickelt.
Dieser Beitrag demonstriert die Anwendbarkeit der Wirbelstromprüfung mit GMR-Sensoren für die Online-Prüfung von PBF-LB/M-Teilen. Die Ergebnisse einer Online-Wirbelstromprüfung mit GMR-Sensoren und einer Ein-Draht-Anregung werden vorgestellt. Während des Produktionsprozesses wird jede Lage mittels Wirbelstromprüfung kontrolliert. Dank eines hochauflösenden Arrays mit 128 Elementen und angepasster Hardware bleibt die Prüfdauer gering. So kann die Messung während des Beschichtungsvorgangs erfolgen, ohne den Fertigungsprozess erheblich zu verlangsamen. Eine Online-Wirbelstromprüfung u.a. eines stufenförmigen Testkörpers aus Haynes282 über 184 Lagen zeigt, dass Kanten nicht nur in der aktuellen Lage, sondern auch in einer Tiefe von 400 μm bei einer Anregungsfrequenz von bis zu 1,2 MHz erkannt werden können.
T2 - Netzwerk ZfP
CY - Linz, Austria
DA - 19.09.2024
KW - Wirbelstromprüfung
KW - Prozessüberwachung
KW - GMR
KW - PBF/LB-M
KW - Additive Fertigung
PY - 2024
AN - OPUS4-61771
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Fundamentals of Energy harvesting
N2 - An introduction to the principles of energy harvesting and conversion, the main technology types and their application is given. A particular focus is on thermomagnetic energy harvesting.
T2 - EU ITN Heat4Energy School
CY - Dresden
DA - 14.10.2024
KW - Energy harvesting
KW - Magnetic materials
PY - 2024
AN - OPUS4-62285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Mohring, Wencke
A1 - Wolf, Marcus
T1 - The insignificant improvement of corrosion and corrosion fatigue behavior in geothermal environment applying Boehmit coatings on high alloyed steels
N2 - The efficacy of alumina-sol based coatings in a water-free atmosphere at high temperatures suggests a potential solution for enhancing the corrosion resistance of high-alloyed steels in Carbon Capture and Storage (CCS) environments. In this study, coupons of X20Cr13, designed for use as injection pipes with 13% Chromium and 0.20% Carbon (1.4021, AISI 420), were sol-gel coated with water and ethanol-based alumina. These coated coupons were then exposed to CO2-saturated saline aquifer water, simulating conditions in the Northern German Basin, for 1000 h at ambient pressure and 60 °C. Corrosion fatigue experiments were also conducted using specimens of X5CrNiMoCuNb16-4 (1.4542, AISI 630), a suitable candidate for geothermal applications, to assess the impact of the ethanol-based coating on the number of cycles to failure at different stress amplitudes. Unfortunately, the coating exhibited early spallation, resulting in corrosion kinetics and corrosion fatigue data identical to those of uncoated specimens. Consequently, the initially promising Boehmit coating is deemed unsuitable for CCS applications and further research therefore not advisable.
KW - Alumina coating
KW - High alloyed steel
KW - Pitting
KW - Surface corrosion
KW - CO2
KW - Pipeline
KW - Corrosion
KW - CCS
KW - CO2-storage
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623786
DO - https://doi.org/10.3390/app14041575
SN - 2076-3417
VL - 14
IS - 4
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-62378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kärcher, Victor
A1 - Reiker, Tobias
A1 - da Costa, Pedro F.G.M.
A1 - de Camargo, Andrea S.S.
A1 - Zacharias, Helmut
T1 - Quantum control in size selected semiconductor quantum dot thin films
N2 - We introduce a novel technique for coherent control that employs resonant internally generated fields in CdTe quantum dot (QD) thin films at the L-point. The bulk band gap of CdTe at the L-point amounts to 3.6 eV, with the transition marked by strong Coulomb coupling. Third harmonic generation (λ3 = 343 nm, hν = 3.61 eV) for a fundamental wavelength of λ 1 = 1,030 nm is used to control quantum interference of three-photon resonant paths between the valence and conduction bands. Different thicknesses of the CdTe QDs are used to manipulate the phase relationship between the external fundamental and the internally generated third harmonic, resulting in either suppression or strong enhancement of the resonant third harmonic, while the nonresonant components remain nearly constant. This development could pave the way for new quantum interference–based applications in ultrafast switching of nanophotonic devices.
KW - Nonlinear nanophotonics
KW - Quantum interference
KW - Third harmonic
KW - Coherent control
KW - Thin films
KW - Quantum dots
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625859
DO - https://doi.org/10.1515/nanoph-2024-0529
VL - 14
IS - 2
SP - 229
EP - 239
PB - Walter de Gruyter GmbH
AN - OPUS4-62585
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn Setsuko
A1 - Ravaro, Leandro Piaggi
A1 - Brambilla, Gabriel
A1 - Maia, Lauro June Queiroz
A1 - Reza Dousti, Mohammad
A1 - de Camargo, Andrea Simone Stucchi
T1 - Upconverting Nanoparticles and Cu(I) Complex-Based Platform for Oxygen Sensing, Thermometry, and Emission Color Tuning
N2 - Multifunctional nanoplatforms combine different material properties to meet a wide range of applications, allowing highly customizable systems. In this rapidly advancing research field, we introduce a multifunctional nanomaterial based on the synergy between Tm3+-doped upconverting nanoparticles (UCNPs) and a Cu(I) complex (CuCom). This material is designed for oxygen sensing, optical thermometry, and emission color tuning. In various concentrations, the CuCom complex was electrostatically integrated into a mesoporous silica shell surrounding the core UCNPs (UCNP@mSiO2). The optimized system, UCNP@mSiO2@CuCom-10, was evaluated for different applications. Due to the spectral overlap between the CuCom absorption and the nanoparticles emission, excitation at 980 nm allows most of the UV-blue emission output from the UCNPs to be transferred to the CuCom via luminescent resonance energy transfer (LRET), producing red emission from the molecule. The remaining Tm3+ emission enables optical thermometry, while CuCom’s sensitivity to molecular oxygen supports its application in gas sensing. In upconversion mode, the nanoplatform achieved a Stern−Volmer constant for O2 sensing of 1.64 and demonstrated thermometric relative sensitivities of 0.9% and 1% K−1 at room temperature, with a linear response from 193 to 373 K. Additionally, the emission color of UCNP@mSiO2@CuCom-10 can be tuned from blue to white and yellow, by varying the excitation and temperature, adding further functionality to the system. This multifunctional platform suggests promising applications in biology, medicine, and environmental monitoring.
KW - M
KW - O2 sensing
KW - Upconversion
KW - Luminescence resonance energy transfer (LRET)
KW - Optical thermometry
KW - Mesoporous silica shell
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625869
SN - 2574-0970
DO - https://doi.org/10.1021/acsanm.4c06351
VL - 8
SP - 854
EP - 862
PB - American Chemical Society (ACS)
AN - OPUS4-62586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Montazerian, Maziar
A1 - Mauro, John C.
A1 - de Camargo, Andrea S. S.
T1 - Richard Adolf Zsigmondy: Nobel laureate and pioneer in optical glasses
N2 - Austrian chemist Richard A. Zsigmondy was known for his work in colloid chemistry, but his research inspired advancements in optical glasses as well.
KW - Quantum dots
KW - Glass
KW - Richard Zsigmondy
PY - 2024
VL - 103
IS - 9
SP - 38
EP - 40
AN - OPUS4-62590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blaeß, Carsten
T1 - Binder jetting of crystallizing bioactive glass powders
N2 - Customized artificial bone replacement implants made of resorbable bioactive glass (BG) have not yet become widely accepted in clinical use. This is mainly due to the contrariness of sintering ability and appropriate bioactivity. Concurrent crystallization often prevents the generation of dense sinter bodies, especially for additive manufactured 3D scaffolds. The presented study investigates the limits and advantages of crystallization of powder compacts manufactured by binder jetting and uniaxial pressing for different particle size fractions (psf) of two BGs.
T2 - CeramicAM 2024 - 1º
CY - Sao Paulo, Brasil
DA - 19.09.2024
KW - Bioactive glass
KW - Sintering
KW - Crystallization
KW - Additive manufacturing
PY - 2024
AN - OPUS4-62594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Advancing Digital Workflows in Materials Science: The Role of PMDco in Data Integration and Semantic Representation
N2 - The field of Materials Science and Engineering (MSE) is undergoing a transformative shift towards digitalization, emphasizing the need for structured and interoperable data management. The Platform MaterialDigital Core Ontology (PMDco), now in version 3.0, addresses these challenges by providing a robust mid-level semantic framework. PMDco bridges the gap between abstract high-level ontologies, such as the Basic Formal Ontology (BFO) standardized in ISO/IEC 21838-2, and highly specific domain terminologies to ensure consistency and interoperability across diverse MSE applications. Developed through MSE community-based curation, PMDco facilitates the integration of real-world data from experiments, simulations, and industrial processes.
This presentation will explore PMDco's role in enabling advanced digital workflows and its integration into demonstrators within the Platform MaterialDigital (PMD) initiative. Highlighted use cases include the semantic representation of tensile test data in compliance with ISO 6892-1:2019-11, utilizing the corresponding tensile test ontology (TTO) built on PMDco. Through an electronic laboratory notebook (ELN), data from experiments performed by undergraduate students were transformed into machine-actionable knowledge graphs, demonstrating the potential for education and fully digitalized experimental procedures.
Additionally, a possible extension of PMDco as a linking point for semantically representing simulation data will be presented, aligning with the focus of VMAP. This includes linking experimental, simulation, and computational datasets to create comprehensive, FAIR-compliant knowledge ecosystems. By showcasing best practices in data acquisition, semantic integration, and knowledge graph generation, this presentation underscores PMDco’s versatility and its critical role in advancing digital MSE workflows.
T2 - VMAP User Forum 2025
CY - Sankt Augustin, Germany
DA - 18.02.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
KW - PMD Core Ontology
PY - 2025
AN - OPUS4-62607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Chaudhuri, Somsubhro
A1 - Pittner, Andreas
A1 - Winterkorn, Rene
A1 - de Finis, Rosa
A1 - Palumbo, Davide
A1 - Galietti, Umbero
T1 - Thermographic investigation of the anisotropic behaviour of additively manufactured AISI316 steel using DED-Arc
N2 - Additive manufacturing is one of the most promising techniques for industrial production and maintenance, but the specifics of the layered structure must be considered. The Direct Energy Deposition-Arc process enables relatively high deposition rates, which is favourable for larger components. For this study, specimens with different orientations were prepared from one AISI316 steel block – parallel and orthogonal to the deposition plane. Quasistatic tensile loading tests were carried out, monitored by an infrared camera. The obtained surface temperature maps revealed structural differences between both orientations. The consideration of surface temperature transients yields more details about the behaviour of the material under tensile loading than the conventional stress-strain-curve. These preliminary investigations were supplemented by thermographic fatigue trials. Although the anisotropy was also observed during fatigue loading the fatigue behaviour in general was the same, at least for both inspected specimens. The presented results demonstrate the abilities and the potential of thermographic techniques for tensile tests.
T2 - 17th Quantitative Infrared Thermography Conference
CY - Zagreb, Croatia
DA - 01.07.2024
KW - WAAM
PY - 2024
SP - 1
EP - 8
AN - OPUS4-62548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Massimo, Carraturo
A1 - Breese, Philipp P.
A1 - Oster, Simon
ED - Rank, E.
ED - Kollmannsberger, S.
T1 - Thermal model for laser-based powder bed fusion of metal process: modelling, calibration, and experimental validation
N2 - In the present contribution, we propose an effective numerical thermal modeling solution for melt pool simulations in Laser-based Powder Bed Fusion of Metals processes. The proposed model employs an anisotropic conductivity to represent melt pool dynamics effects in a homogeneous material model. The numerical implementation of the proposed physical model is first experimentally calibrated and then validated with respect to a series of melt pool measurements as acquired by using a short-wave infrared (SWIR) camera monitoring system.
T2 - IVth International Conference on Simulation for Additive Manufacturing (Sim-AM 2023)
CY - Munich, Germany
DA - 26.07.2023
KW - Laser powder bed fusion of metals
KW - Melt pool measurements
KW - Experimental validation
KW - Thermal analysis
KW - SS 316L
PY - 2023
DO - https://doi.org/10.23967/c.simam.2023.015
SP - 1
EP - 9
AN - OPUS4-62525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valentini, Martino
A1 - De Almeida, Olivier
A1 - Kakkonen, Markus
A1 - Kalinka, Gerhard
A1 - Dorigato, Andrea
A1 - Kallio, Pasi
A1 - Fredi, Giulia
T1 - Effect of fiber surface state on the thermomechanical and interfacial properties of in situ polymerized polyamide 6/basalt fiber composites
N2 - This study investigates the thermomechanical properties and interfacial adhesion of novel in-situ polymerized anionic polyamide 6 (aPA6) composites reinforced with basalt fibers (BF). The impact of different BF surface states - as-received (BFa), ethanol-washed (BFw), and thermally desized (BFu) on composite performance is examined through a comprehensive approach. For the first time, anionic PA6/BF composites with very low residual monomer content were successfully produced via thermoplastic resin transfer molding (tRTM). The PA6/BFw composites exhibited the highest interlaminar/interfacial shear strength in short beam shear test (52 ±8 MPa) and fiber push out test (34 ± 11 MPa) tests. Fiber microdebonding test, performed only on PA6/BFw, yielded a low interfacial shear strength (12 ± 4 MPa), which was attributed to droplet porosity resulting from concurrent polymerization and crystallization. Thermal desizing significantly deteriorated interfacial strength (19.6 ± 1.2 MPa in short beam shear test). This multi-technique characterization provides insights into optimizing the fiber–matrix adhesion in these advanced thermoplastic composites.
KW - Anionic Polyamide 6
KW - Reactive thermoplastics
KW - Basalt fibers
KW - Microdebonding
KW - Fiber push out
KW - Short beam shear test
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623596
DO - https://doi.org/10.1016/j.compositesa.2024.108681
SN - 1878-5840
VL - 190
SP - 1
EP - 15
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-62359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Genga, R. M.
A1 - Glaser, D.
A1 - Rokebrand, P.
A1 - Cornish, L. A.
A1 - Woydt, M.
A1 - Gradt, Thomas
A1 - Janse van Vuuren, A.
A1 - Polese, C.
ED - von Leipzig, K.
ED - Sacks, N.
ED - McClelland, M.
T1 - Laser shock peening: A NbC based cermet enhancement alternative for improved GCI interrupted face-milling
N2 - Attempts were made to improve the properties and machining performance of NbC based cermet cutting inserts for face milling of grey cast iron (GCI) (BS 1452/GG35) by spark plasma sintering (SPS), use of sub-stoichiometric NbC (NbC₀ˏ₈₈), Cr₃C₂ and Mo₂C additives and laser shock peening (LSP). The microstructure, hardness, fracture toughness and Young’s modulus of WC–Co, NbC₀ˏ₈₈-Co and NbC₀ˏ₈₈-Ni cermet-based inserts were investigated for machining performance. Additions of Mo₂C and manufacture by SPS significantly refined the NbC₀ˏ₈₈-Ni/Co cermet’s carbide grain size from ~5.0 μm to <0.9 μm, which increased the hardness (by ~4GPa) and wear resistance. Laser shock peening (LSP) improved the fracture toughness of all the inserts, from 10% (in the SPS WC based in cermets) to ~100% (in the LPS NbC based cermets). Uncoated cutting inserts were manufactured from the sintered cermets in an SNMA (double sided square insert without a chipformer on the cutting edge) shape (12.7 × 12.7 × 4.3 mm³, 1.6 mm nose radius). The inserts were used for interrupted face-milling of GCI at cutting speeds (ν˛) ranging from 100 m/minute (400 rpm)–500 m/minute (2000 rpm) and depths of cut (ɑₚ) of 0.2–1.0 mm. The insert wear was measured after every pass and analyzed by annular dark field scanning transmission electron microscopy (ADF-STEM). Cutting temperatures were measured with a high-speed thermal camera and forces were measured using a Kistler dynamometer. During machining at ν˛ = 200 m/minute and ɑₚ = 1.0 mm, WC–Co inserts had the lowest flank wear rate (FWR), although LSP significantly improved the tool life of the NbC₀ˏ₈₈-Ni inserts, significantly reducing the FWR from 148.63 μm/minute to 99.79 μm/minute (by ~33%) and the average resultant force from 1257 ± 15 N to 535 ± 15 N. During machining at ν˛ = 500 m/minute and ɑₚ = 0.2 mm, LSP significantly lowered the FWRs of the NbC₀ˏ₈₈ inserts, giving better tool life than all the WC based inserts. Generally, LSP improved the NbC₀ˏ₈₈ inserts’ tool life, reducing the flank wear rate by up to 33% during roughing and 63% during finishing.
T2 - 8th International Conference on Competitive Manufacturing (COMA ’22)
CY - Stellenbosch, South Africa
DA - 09.03.2022
KW - Niobium carbide
KW - Laser shock peening
KW - Face milling
KW - Tool wear
PY - 2023
SN - 978-3-031-15602-1
SN - 978-3-031-15601-4
SN - 978-3-031-15604-5
DO - https://doi.org/10.1007/978-3-031-15602-1_62
SN - 2194-0525
SN - 2194-0533
N1 - Serientitel: Lecture notes in production engineering – Series title: Lecture notes in production engineering
SP - 871
EP - 889
PB - Springer
CY - Cham
AN - OPUS4-62689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asante, Bright
T1 - Optimized mix design and fire resistance of geopolymer recycled aggregate concrete under elevated temperatures
N2 - This study investigates the performance of fly ash-based geopolymer recycled aggregate concrete (GRAC) as a sustainable alternative to Ordinary Portland Cement (OPC) concrete, focusing on its compressive strength and behavior under high-temperature exposure (150 ◦C, 300 ◦C, 600 ◦C, and 900 ◦C). The research emphasizes the use of 100 % recycled concrete aggregates as a replacement for natural aggregates, with samples cured at ambient conditions and at 60 ◦C in an oven. Key factors, including water content and curing conditions, were evaluated to determine their influence on compressive strength and thermal stability. Results indicate that water content is the primary factor governing compressive strength, while recycled aggregates contribute to a secondary but notable effect. GRAC maintained up to 65 % of its initial strength after exposure to 600 ◦C, though strength degradation and severe cracking occurred at 900 ◦C. Oven-cured samples showed fewer surface cracks but experienced slightly higher mass loss than room-cured coun-terparts. This study highlights the potential of GRAC as an environmentally friendly material capable of withstanding moderate thermal conditions, providing significant contributions to green construction practices and the reuse of construction and demolition waste.
KW - Geopolymer
KW - Recycled aggregate concrete
KW - Elevated temperature
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627071
DO - https://doi.org/10.1016/j.cscm.2025.e04401
SN - 2214-5095
VL - 22
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-62707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
A1 - Mishmastnehi, Moslem
T1 - What can we learn from traditional stucco masters?
N2 - Historical plaster formulations represent an underexplored avenue for understanding advanced materials engineering in premodern cultures. In this contribution, we investigate two distinct historical gypsum plasters, Gach-e Koshteh from 14th century Persia and Gesso Sottile from 15th century Italy, both of which were essential for architectural decoration and fine art. By replicating these methods in a laboratory setting, we explore how traditional artisans manipulated gypsum microstructures without any additives, to optimize surface and mechanical properties for specific artistic and functional outcomes.
Gach-e Koshteh employs a labor-intensive process involving kneading and mechanical treatment during hydration of bassanite to gypsum. This results in a plaster with a platelet-like crystal morphology and a pronounced alignment of the {010} faces, leading to a hydrophilic surface ideal for water-based decoration. These platelets form a compacted structure, reducing porosity while providing a smooth, workable surface for wall paintings. In contrast, Gesso Sottile relies on a slow recrystallization process in a large excess of water, yielding needle-like gypsum crystals that minimize hydrophilic surface area. This makes Sottile more suitable for oil-based panel paintings or as a substrate for gilding.
Our study applies a combination of wide-angle X-ray scattering (WAXS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) to reveal the microstructural and surface properties of these historical plaster recipes. We demonstrate that the mechanical treatment in the Koshteh method leads to a denser, better-packed plaster with enhanced wettability due to the increased exposure of hydrophilic crystallographic planes. Meanwhile, the extended treatment time and high dilution in the Sottile recipe promote larger, loosely packed needle crystals that create a more hydrophobic surface.
These findings not only highlight the ingenuity of historical materials engineering but also provide valuable insights for modern restoration and preservation techniques. By understanding the role of microstructure in the durability and surface properties of historical plasters, we can improve the conservation of gypsum-based cultural heritage objects. This research also demonstrates the potential for sustainable materials engineering practices rooted in historical techniques, as these additive-free formulations exhibit long-lasting performance with minimal environmental impact.
T2 - Granada Muenster Discussion Meeting, GMDM2024
CY - Granada, Spain
DA - 27.11.2024
KW - Gypsum
PY - 2024
AN - OPUS4-62004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alem, Sayed Ali Ahmad
A1 - Sabzvand, Mohammad Hossein
A1 - Govahi, Parnian
A1 - Poormehrabi, Pooria
A1 - Azar, Mahdi Hasanzadeh
A1 - Siouki, Sara Salehi
A1 - Rashidi, Reza
A1 - Angizi, Shayan
A1 - Bagherifard, Sara
T1 - Advancing the next generation of high-performance metal matrix composites through metal particle reinforcement
N2 - Metal matrix composites (MMCs) offer asignificant boost to achieve a wide range of advanced mechanical properties and improved performance for a variety of demanding applications. The addition of metal particles as reinforcement in MMCs is an exciting alternative to conventional ceramic reinforcements, which suffer from numerous shortcomings. Over the last two decades, various categories of metal particles, i.e., intermetallics, bulk metallic glasses, high-entropy alloys, and shape memory alloys, have become popular as reinforcement choices for MMCs. These groups of metal particles offer a combination of outstanding physico-mechanical properties leading to unprecedented performances; moreover, they are significantly more compatible with the metal matrices compared to traditional ceramic reinforcements. In this review paper, the recent developments in MMCs are investigated. The importance of understanding the active mechanisms at the interface of the matrix and the reinforcement is highlighted. Moreover, the processing techniques required to manufacture high-performance MMCs are explored identifying the potential structural and functional applications. Finally, the potential advantages and current challenges associated with the use of each reinforcement category and the future developments are critically discussed. Based on the reported results, the use of metal particles as reinforcement in MMCs offers a promising avenue for the development of advanced materials with novel mechanical properties. Further progress requires more in-depth fundamental research to realize the active reinforcing mechanisms at the atomic level to precisely identify, understand, and tailor the properties of the integrated composite materials.
KW - Intermetallic
KW - Composite
KW - Metal matrix composite
KW - Interface
KW - High entropy alloy
KW - Bulk metallic glass
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620730
DO - https://doi.org/10.1007/s42114-024-01057-4
SN - 2522-0128
VL - 8
IS - 1
SP - 1
EP - 68
PB - Springer Nature
AN - OPUS4-62073
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rasool, Muhammad Hammad
A1 - Ahmad, Maqsood
A1 - Siddiqui, Numair Ahmed
A1 - Junejo, Aisha Zahid
T1 - Eco-friendly drilling fluid: Calcium chloride-based natural deep eutectic solvent (NADES) as an all-rounder additive
N2 - Designing an effective drilling mud is a critical aspect of the drilling process. A well-designed drilling mud should not only provide efficient mud hydraulics but also fulfill three important functions: enhancing mud rheology, inhibiting hydrate formation in deepwater drilling, and suppressing shale swelling when drilling through shale formations. Achieving these functions often requires the use of various additives, but these additives are often expensive, non-biodegradable, and have significant environmental impacts. To address these concerns, researchers have explored the potential applications of ionic liquids and deep eutectic solvents in drilling mud design, which have shown promising results. However, an even more environmentally friendly alternative has emerged in the form of natural deep eutectic solvents (NADES). This research focuses on an in-house-prepared NADES based on calcium chloride and glycerine, with a ratio of 1:4, prepared at 60 °C, and utilizes it as a drilling mud additive following the API 13 B-1 standards and checks its candidacy as a rheology modifier, hydrates, and shale inhibitor. The findings of the study demonstrate that the NADES-based mud significantly improves the overall yield point to plastic viscosity ratio (YP/PV) of the mud, provides good gel strength, and inhibits hydrate formation by up to 80%. Additionally, it has shown an impressive 62.8% inhibition of shale swelling while allowing for 84.1% improved shale recovery. Moreover, the NADES-based mud exhibits a 28% and 25% reduction in mud filtrate and mud cake thickness, respectively, which is further supported by the results of XRD, zeta potential, and surface tension. Based on these positive outcomes, the calcium chloride–glycerine NADES-based mud is recommended as a versatile drilling mud additive suitable for various industrial applications. Furthermore, it presents a more environmentally friendly option compared to traditional additives, addressing concerns about cost, biodegradability, and environmental impact in the drilling process for an ultimate global impact.
KW - NADES
KW - Shale swelling
KW - Drilling fluid
KW - Mud rheology
KW - Hydrate inhibition
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623918
DO - https://doi.org/10.3390/en16145533
SN - 1996-1073
VL - 16
IS - 14
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-62391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, André
A1 - Hasenbein, Ines
A1 - Hortschansky, Peter
A1 - Schmuck, Klaus D.
A1 - Maenz, Stefan
A1 - Illerhaus, Bernhard
A1 - Kuehmstedt, Peter
A1 - Ramm, Roland
A1 - Huber, René
A1 - Kunisch, Elke
A1 - Horbert, Victoria
A1 - Gunnella, Francesca
A1 - Roth, Andreas
A1 - Schubert, Harald
A1 - Kinne, Raimund W.
T1 - BMP-2 (and partially GDF-5) coating significantly accelerates and augments bone formation close to hydroxyapatite/tricalcium-phosphate/brushite implant cylinders for tibial bone defects in senile, osteopenic sheep
N2 - Bilateral defects (diameter 8 mm) in the medial tibial head of senile, osteopenic female sheep (n = 48; 9.63 ± 0.10 years; mean ± SEM) were treated with hydroxyapatite (HA)/beta-tricalcium phosphate (β-TCP)/dicalcium phosphate dihydrate (DCPD; brushite) cylinders coated with BMP-2 (25 or 250 micrograms) or growth differentiation factor (GDF)-5 (125 or 1250 micrograms; left side); cylinders without BMP served as controls (right side). Three, 6, and 9 months post-operation (n = 6 each group), bone structure and formation were analyzed in vivo by X-ray and ex vivo by osteodensitometry, histomorphometry, and micro-computed tomography (micro-CT) at 3 and 9 months. Semi-quantitative X-ray evaluation showed significantly increasing bone densities around all implant cylinders over time. High-dose BMP-2-coated cylinders (3 and 9 months) and low-dose GDF-5-coated cylinders (3 and 6 months) demonstrated significantly higher densities than controls (dose-dependent for BMP-2 at 3 months). This was confirmed by osteodensitometry at 9 months for high-dose BMP-2-coated cylinders (and selected GDF-5 groups), and was again dose-dependent for BMP-2. Osteoinduction by BMP-2 was most pronounced in the adjacent bone marrow (dynamic histomorphometry/micro-CT). BMP-2 (and partially GDF-5) significantly increased the bone formation in the vicinity of HA/TCP/DCPD cylinders used to fill tibial bone defects in senile osteopenic sheep and may be suitable for surgical therapy of critical size, non-load-bearing bone defects in cases of failed tibial head fracture or defect healing.
KW - Bone morphogenetic protein (BMP)
KW - Growth differentiation factor (GDF)
KW - Bone replacement material
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623923
DO - https://doi.org/10.1007/s10856-023-06734-2
SN - 1573-4838
VL - 34
IS - 7
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
CY - Dordrecht
AN - OPUS4-62392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dolai, Malay
A1 - Saha, Urmila
A1 - Goswami, Juli Nanda
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Ifseisi, Ahmad A.
A1 - Biswas, Surajit
ED - Bhattacharya, Biswajit
T1 - Nickel(II)-mediated in situ complex formation with unexpected ligand transformations: crystal structures, DFT calculations, and catalytic activity in CO2 fixation reactions
N2 - Two transformed ligands, namely 1,3,5-triazapentadienato(imidoylamidinato) and N-(methoxy(pyrimidin-2-yl)(pyrimidine-2-carboxamido)methyl)pyrimidine-2-carboxamide, are reported here as the first products derived from 2-cyano pyridine/pyrimidine, respectively, under nickel metal mediation in the presence of hydroxylamine hydrochloride in situ. Two different nickel-coordinated complexes (1 and 2) were formed. Single crystal X-ray diffraction revealed that complex 1 is a mononuclear complex with tetra-coordinated square planar geometry, whereas complex 2 is a dinuclear complex with hexa-coordinated distorted octahedral geometry. The synthetic pathways of both transformed ligands are explained with the support of energy calculations of different states via density functional theory (DFT) calculations. The catalytic addition reactions of epoxides and carbon dioxide efficiently produce organic cyclic carbonates in the presence of complexes 1–2, attributed to the presence of Lewis acidic nickel and Lewis basic centers, such as free amine, imine, methoxy, or nitrogen in complexes 1 and 2. Under mild reaction conditions (1 atm CO2 pressure and 60 °C temperature), different types of epoxides (exocyclic, endocyclic, and aromatic epoxides) yield high levels of respective cyclic carbonates in the presence of both complexes 1–2 as catalysts, with tert-butylammonium bromide (TBAB) acting as a co-catalyst. The high turnover number (TON) and turnover frequency (TOF) of these catalytic reactions clearly indicate the efficacy of the two catalysts.
KW - Catalytic activity in CO2 fixation reactions DFT calculations
KW - Nickel(II)-complex
KW - In situ complex formation
KW - Crystal Structure
PY - 2025
DO - https://doi.org/10.1039/d4nj01801j
SN - 1369-9261
VL - 49
IS - 11
SP - 4451
EP - 4463
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - EOS M300 as the heart of the QI living lab: Advancing with digital process chains
N2 - This presentation shows how the connectivity of the EOS-M300/4 laser powder bed system is used to capture machine and process data as part of the living lab in QI Digital and how this can enable future digital quality assurance in additive manufacturing.
T2 - AM Forum 2025
CY - Berlin, Germany
DA - 17.03.2025
KW - Additive manufacturing
KW - Quality assurance
KW - QI Digital
KW - Living lab
PY - 2025
AN - OPUS4-62740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Saber, Yassin
A1 - Clague, Leighton
T1 - Automated Fused Filament Fabrication of Ceramics and Metals - Remote and in Space
N2 - Component manufacturing in remote (i.e., geographically isolated) settings poses significant challenges where access to conventional manufacturing facilities is limited or non-existent. Fused Filament Fabrication (FFF) enables the rapid manufacturing of plastic, metallic and ceramic components with complex geometries. Ceramic and metallic parts formed by FFF require subsequent debinding and sintering to reach full density. Debinding and sintering are typically executed in separate steps with different equipment, necessitating extensive human handling which hinders process automation and may be challenging for the operator in isolated environments. Here an innovative approach is presented: the integration of all process steps into a single, fully automated system, streamlining the process and minimizing human involvement. Our system combines a dual extrusion filament printer with a porous and heat-resistant ceramic print bed. The porous print bed enables mechanical interlocking of the first printed layers, ensuring adhesion and structural integrity during FFF. Ceramic and metallic parts are printed onto thin sacrificial rafts, which are built using an interface material with the same binder as the loaded filament. After the print is completed, the heat-resistant print bed with all parts is transferred seamlessly with a carrier system into a high-temperature furnace for debinding and sintering. During sintering the sacrificial raft is disintegrated, allowing for unconstrained sintering and easy removal of the finished parts. In conclusion, our integrated approach enables significant advancements in the fabrication of complex ceramic or metallic components in remote environments with increased efficiency and minimal human handling.
T2 - AM Forum 2025
CY - Berlin, Germany
DA - 17.03.2025
KW - Fused Filament Fabrication
KW - Ceramics
KW - Metalls
KW - Process automation
PY - 2025
AN - OPUS4-62745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Mike
A1 - Couzinié, Jean-Philippe
A1 - Shalabi, Amin
A1 - Ibrahimkhel, Farhad
A1 - Ferrari, Alberto
A1 - Körmann, Fritz
A1 - Laplanche, Guillaume
T1 - Effect of stacking fault energy on the thickness and density of annealing twins in recrystallized FCC medium and high-entropy alloys
N2 - This work aims to predict the microstructure of recrystallized medium and high-entropy alloys (MEAs and HEAs) with a face-centered cubic structure, in particular the density of annealing twins and their thickness. Eight MEAs and five HEAs from the Cr-Mn-Fe-Co-Ni system are considered, which have been cast, homogenized, cold-worked and recrystallized to obtain different grain sizes. This work thus provides a database that could be used for data mining to take twin boundary engineering for alloy development to the next level. Since the stacking fault energy is known to strongly affect recrystallized microstructures, the latter was determined at 293 K using the weak beam dark-field technique and compared with ab initio simulations, which additionally allowed to calculate its temperature dependence. Finally, we show that all these data can be rationalized based on theories and empirical relationships that were proposed for pure metals and binary Cu-based alloys.
KW - CoCrFeMnNi HEAs and MEAs
KW - Recrystallization
KW - Transmission electron microscopy (TEM)
KW - Electron backscatter diffraction
KW - Grain boundary engineering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629346
DO - https://doi.org/10.1016/j.scriptamat.2023.115844
SN - 1359-6462
VL - 240
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Digital Transformation in Materials Science through Semantic Technologies and Knowledge Graphs
N2 - The field of materials science is undergoing a transformative shift driven by digitalization. In this respect, semantic and AI technologies are paving the way for advancements in materials development, design, and optimization while leaping towards an Industry 4.0 environment. Addressing the dual challenges of quality assurance and data interoperability, this presentation examines the integration of semantic technologies and knowledge representation methods. By adhering to FAIR principles, this approach enhances data management, storage, and reuse. That way, both machine-actionable and human-understandable data structures crucial for digital research environments are fostered.
This presentation focuses on the ‘platform MaterialDigital’ (PMD) initiative, which aims to support efforts from both industrial and academic sectors to solve digitalization challenges and implement sustainable digital solutions. Besides establishing structures to create virtual material data spaces, PMD develops solutions for systematizing and unifying the handling of hierarchical, process-dependent material data. Semantic technologies play a crucial role in digitalization efforts as they enable the storage, processing, and querying of data in a contextualized form. Therefore, the development and prototypical application of the PMD Core Ontology 3.0 (PMDco 3.0) tailored for materials science is highlighted. This includes the design and documentation of graph patterns that may be compiled into rule-based semantic shapes. Its integration into daily lab life is demonstrated through its application to electronic lab notebooks (ELN). This illustrates potentials of standardized protocols and automation-ready solutions for managing diverse experimental data across different sources.
Outlining best practices and illustrating the possibilities that semantic technologies bring to modern labs, examples from materials processing and mechanical testing will underscore how knowledge graphs bridge the gap between data and decision-making in materials science, with potential for increased productivity and streamlined workflows across the field.
T2 - Materials Week 2025
CY - Frankfurt am Main, Germany
DA - 03.04.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
KW - PMD Core Ontology
PY - 2025
AN - OPUS4-62866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Kun
A1 - Lin, Chang
A1 - Pan, Lisha
T1 - Effect of sisal fibers on the rheology of cement paste plasticized by polycarboxylate superplasticizer
N2 - Sisal fibers (SF) and polycarboxylate superplasticizers (PCE) contribute to the sustainable development of cementitious materials by improving and optimizing their hardening properties. In this study, the impact of SF and PCE on the workability of cement pastes was investigated. The workability was evaluated through spreading diameter, yield stress, and plastic viscosity measurements, and the adsorption behavior of PCE was analyzed. The results showed that the introduction of SF had a negative effect on the workability of PCE plasticized cement pastes, reducing flowability and increasing yield stress and plastic viscosity, regardless of aspect ratio or dosage. A contact angle tester and a scanning electron microscope (SEM) were employed to examine the surface properties of SF. The mechanism behind this interaction of cement-PCE-SF was explored and found to be due to the rough surface of SF, which increased the consumption of PCE, and the formation of hydrogen bonds between PCE and SF. Additionally, PCE modified the interfacial structure between SF and the cement matrix, strengthening the relationship between the different phases. These findings provide new insights into the modification of fiber-reinforced cementitious materials.
KW - Cement paste
KW - Polycarboxylate
KW - Flowability
KW - Rheological
KW - Sisal fiber (SF)
KW - Adsorption
PY - 2024
DO - https://doi.org/10.1061/jmcee7.mteng-16789
SN - 0899-1561
VL - 36
IS - 3
SP - 1
EP - 12
PB - American Society of Civil Engineers (ASCE)
CY - Reston, VA
AN - OPUS4-62893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
A1 - John, Elisabeth
A1 - Firdous, Rafia
A1 - Hirsch, Tamino
A1 - Kaczmarek, Daria
A1 - Ziesack, Kevin
A1 - Buchwald, Anja
A1 - Stephan, Dietmar
A1 - Kruschwitz, Sabine
ED - Ferrara, Liberato
ED - Muciaccia, Giovanni
ED - di Summa, Davide
T1 - Beyond Theory: Pioneering AI-Driven Materials Design in the Sustainable Building Material Lab
N2 - This work focuses on Artificial Intelligence (AI)-driven materials design, addressing the challenge of improving the sustainability of building materials amid complex formulations. These formulations involve various components, such as binders, additives, and recycled aggregates, necessitating a balance between environmental impact and performance. Traditional experimental methods often fall short in managing the complexity of material composition, hindering fast enough development of optimal solutions. Our research explores complex composition materials design through a comprehensive, comparative lab study between Data-Driven Design, using SLAMD - an open-source AI materials design tool, and traditional Design of Experiments (DOE). We aimed to develop a high-performance, alkali-activated material using secondary precursors, aiming for a compressive strength exceeding 100 MPa after 7-days. The findings reveal that AI-driven design outperforms DOE in development speed and material quality, successfully identif.
T2 - 4 RILEM Spring Convention and Conference on advanced construction materials and processes for a carbon neutral society 2024
CY - Milano, Italy
DA - 07.04.2024
KW - Secondary Raw Materials
KW - Data-Driven Design
KW - Sequential Learning
KW - Design of Experiments
KW - Alkali-Activated Binder
PY - 2024
SN - 978-3-03170281-5
DO - https://doi.org/10.1007/978-3-031-70281-5_31
SN - 2211-0852
VL - 2
SP - 274
EP - 282
PB - Springer
AN - OPUS4-61662
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zia, Ghezal Ahmad Jan
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
A1 - Kruschwitz, Sabine
T1 - An Adaptive Upscaling Approach for Assessing Materials’ Circularity Potential with Non-destructive Testing (NDT)
N2 - Advancing towards a circular economy necessitates the efficient reuse and maintenance of structural materials, which relies on accurate, non-damaging condition assessments. This paper introduces an innovative AI-driven adaptive sampling (AS) technique integrated with Non-Destructive Testing (NDT) to optimize this process. AS focuses on critical data points, reducing the amount of data needed for precise assessments—evidenced by our method requiring on average only 7 samples for Logistic Regression and 8 for Random Forest, contrasted with 29 for traditional sampling.
By reducing the necessity for extensive data collection, our method not only streamlines the assessment process but also significantly contributes to the sustainability goals of the circular economy. These goals include resource efficiency, waste reduction, and material reuse. Efficient condition assessments promote infrastructure longevity, reducing the need for new materials and the associated environmental impact.
The circular economy aims to create a sustainable system where resources are reused, and waste is minimized. This is achieved by extending the lifecycle of materials, reducing the environmental footprint, and promoting recycling and reuse. Longevity directly contributes to the circular economy by maximizing the utility and lifespan of existing materials and structures. Longer-lasting infrastructure means fewer resources are needed for repairs or replacements, leading to reduced material consumption and waste generation. This aligns with the circular economy's principles of sustainability and resource efficiency. This research not only advances the field of structural health monitoring but also aligns with the broader objective of enhancing sustainable construction practices within the circular economy framework.
T2 - Rilem Spring Convention
CY - Milano, Italy
DA - 09.04.2024
KW - Adaptive Sampling
KW - Random Sampling
KW - Machine Learning
KW - Non-Destructive Testing
KW - Condition Assessment
KW - Circular Economy
PY - 2024
SN - 978-3-031-70277-8
DO - https://doi.org/10.1007/978-3-031-70277-8_38
SN - 2211-0844
VL - 55
SP - 330
EP - 338
PB - Springer Nature Switzerland
CY - Switzerland
AN - OPUS4-62458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Paul, Nathalie
A1 - Kister, Alexander
A1 - Schnellhardt, Thorben
A1 - Fetz, Maximilian
A1 - Hecker, Dirk
A1 - Wirtz, Tim
ED - Meo, Rosa
ED - Silvestri, Fabrizio
T1 - Reinforcement Learning for Segmented Manufacturing
N2 - The manufacturing of large components is, in comparison to small components, cost intensive. This is due to the sheer size of the components and the limited scalability in number of produced items. To take advantage of the effects of small component production we segment the large components into smaller parts and schedule the production of these parts on regular-sized machine tools. We propose to apply and adapt recent developments in reinforcement learning in combination with heuristics to efficiently solve the resulting segmentation and assignment problem. In particular, we solve the assignment problem up to a factor of 8 faster and only a few percentages less accurate than a classic solver from operations research.
T2 - European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases 2023
CY - Turin, Italy
DA - 18.09.2023
KW - Reinforcement Learning
KW - Assignment Problem
KW - Large component manufacturing
PY - 2025
DO - https://doi.org/10.1007/978-3-031-74640-6_38
VL - 1
IS - 1
SP - 470
EP - 485
PB - Springer Cham
AN - OPUS4-63031
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Siefke, Lennart
A1 - Linden, Anna
T1 - Towards a robust automated surface inspection method for CT-scanned cannulas
N2 - For certain cardiovascular diseases, cannulas are implanted into the blood circuit. To match the patients individual anatomy of the heart, there is research for cannulas to be custom-designed and manufactured aided by 3D printing. However, cannulas have to hold very high standards with regard to the smoothness of their surfaces, as rough patches can lead to formation of
blood clots. Therefore, this work uses computer vision to detect such patches as part of quality assurance. First, the produced cannula is scanned using a precise CT scanner and transformed into a 3D mesh object. Rough patches in an otherwise smooth but curved surface are detected by using cosine similarity between neighboring faces and a statistical evaluation. In the end, this method is able to raise a warning when curved surfaces are not smooth enough and visualizes the problematic patches. However, there is just limited access to test data currently and the scanner used needs to be upgraded.
T2 - 3D in Science & Applications (3D-iSA) 2024
CY - Berlin, Germany
DA - 26.11.2024
KW - Algorithm
KW - Additive manufacturing
KW - Surface evaluation
PY - 2025
UR - https://www.gfai.de
SN - 978-3-942709-34-7
SP - 66
EP - 70
AN - OPUS4-63057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reigl, Selina
A1 - Van Driessche, Alexander
A1 - Stawski, Tomasz
A1 - Koltzenburg, Sebastian
A1 - Kunz, Werner
A1 - Kellermeier, Matthias
T1 - Sustainable Pathways for the Synthesis of Calcium Sulfate Hemihydrate
N2 - Calcium sulfate, and especially its hemihydrate form (bassanite), is crucial in the construction industry, primarily used as a hydraulic binder in cements, mortars, and wallboards. Because of the rapid transformation of bassanite into thermodynamically stable gypsum (calcium sulfate dihydrate) upon contact with water, natural deposits are scarce, rendering it one of the most extensively produced inorganic materials worldwide. Currently, bassanite is derived from mined or waste gypsum through a thermal dehydration process, which is energy-intensive and costly. As sustainability has become a key target for industrial processes and products, a series of studies aiming to increase the energy efficiency and reduce the carbon footprint of bassanite production was published recently. Two primary approaches are pursued: conversion of gypsum and direct precipitation of bassanite from solution. In both cases, organic solvents, (specific) additives and/or elevated temperatures have been used to control the activity/availability of water in the reaction medium and thus direct phase selection towards bassanite. This review offers a comprehensive overview of alternative bassanite production methods, critically examining their benefits, potential downsides, and overall impact on
the sustainability of industrial-scale use.
KW - Calcium sulfate
KW - Gypsum
KW - Bassanite
KW - Recycling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630657
DO - https://doi.org/10.1002/anie.202415161
SN - 1521-3773
SP - 1
EP - 20
PB - Wiley VHC-Verlag
AN - OPUS4-63065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Alexander
A1 - Dingel, Kristina
A1 - Kottke, Daniel
A1 - Degener, Sebastian
A1 - Meier, David
A1 - Sick, Bernhard
A1 - Niendorf, Thomas
T1 - Data selection strategies for minimizing measurement time in materials characterization
N2 - Every new material needs to be assessed and qualified for an envisaged application. A steadily increasing number of new alloys, designed to address challenges in terms of reliability and sustainability, poses significant demands on well-known analysis methods in terms of their efficiency, e.g., in X-ray diffraction analysis. Particularly in laboratory measurements, where the intensities in diffraction experiments tend to be low, a possibility to adapt the exposure time to the prevailing boundary conditions, i.e., the investigated microstructure, is seen to be a very effective approach. The counting time is decisive for, e.g., complex texture, phase, and residual stress measurements. Traditionally, more measurement points and, thus, longer data collection times lead to more accurate information. Here, too short counting times result in poor signal-to-background ratios and dominant signal noise, respectively, rendering subsequent evaluation more difficult or even impossible. Then, it is necessary to repeat experiments with adjusted, usually significantly longer counting time. To prevent redundant measurements, it is state-of-the-art to always consider the entire measurement range, regardless of whether the investigated points are relevant and contribute to the subsequent materials characterization, respectively. Obviously, this kind of approach is extremely time-consuming and, eventually, not efficient. The present study highlights that specific selection strategies, taking into account the prevailing microstructure of the alloy in focus, can decrease counting times in X-ray energy dispersive diffraction experiments without any detrimental effect on data quality for the subsequent analysis. All relevant data, including the code, are carefully assessed and will be the basis for a widely adapted strategy enabling efficient measurements not only in lab environments but also in large-scale facilities.
KW - Materials characterization
KW - Machine learning
KW - X-ray diffraction
KW - Measurement optimization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630831
DO - https://doi.org/10.1038/s41598-025-96221-1
SN - 2045-2322
VL - 15
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-63083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zia, Ghezal Ahmad Jan
A1 - Valdestilhas, Andre
A1 - Moreno Torres, Benjami
A1 - Kruschwitz, Sabine
T1 - Leveraging large language models for automated knowledge graphs generation in non-destructive testing
N2 - This paper presents an innovative approach for the automatic generation of Knowledge Graphs (KGs) from heterogeneous scientific articles in the domain of Non-Destructive Testing (NDT) applied to building materials.
Our methodology leverages large language models (LLMs) to extract and semantically relate concepts from diverse sources. We developed material-specific agents for concrete, wood, steel, and bricks, each equipped with a curated glossary of terms to ensure domain accuracy. These agents process PDF documents, extracting relevant information on deterioration mechanisms, physical changes, and applicable NDT methods. The extracted data is then normalized, validated, and structured into a Neo4j graph database, forming a comprehensive KG. Our results demonstrate the system’s ability to automatically discover and represent intricate relationships between materials, deterioration mechanisms, physical changes, and NDT techniques. The generated KG successfully captures complex interactions, such as the applicability of specific NDT methods to various materials under different deterioration conditions. This work not only highlights the potential of KGs in enhancing knowledge discovery and representation in NDT research but also provides a scalable framework for extending this approach to other scientific domains.
T2 - SeMatS 2024 - The 1st International Workshop on Semantic Materials Science
CY - Amsterdam, The Netherlands
DA - 17.09.2024
KW - Materials science and engineering
KW - Large language model
KW - Linked open data
KW - Data interoperability
KW - RDF
KW - Semantic web
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624597
DO - https://doi.org/10.5281/zenodo.13834164
SN - 1613-0073
N1 - Serientitel: CEUR workshop proceedings – Series title: CEUR workshop proceedings
VL - 3760
SP - 101
EP - 110
PB - RWTH Aachen
CY - Aachen
AN - OPUS4-62459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Neues aus der BAM / Fachbereich 9.2
N2 - In dieser Präsentation werden die neuesten Herausforderungen und der Stand des Fachbereiches 9.2 für die Mitarbeit im AK des HGF "Bau wissenschaftlicher Geräte" dargestellt. Hierfür werden Neuigkeiten aus dem Bereich Materialprüfung in der BAM präsentiert und mit den Arbeiten der Zentralwerkstatt, die hierfür notwendig sind, in Zusammenhang gebracht.
T2 - Helmholtz-Arbeitskreis "Bau wissenschaftlicher Geräte"
CY - Berlin, Germany
DA - 12.06.2024
KW - Fertigungsverfahren
KW - Fertigungskompetenz
PY - 2024
AN - OPUS4-62293
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
ED - Valdestilhas, Andre
ED - Li, H.
ED - Lambrix, P.
ED - Sack, H.
T1 - SeMatS 2024 - Proceedings of the first international workshop on semantic materials science: Harnessing the power of semantic web technologies in materials science
N2 - Advanced technological solutions play a vital role in leveraging the potential of data and driving innovative research. However, the compatibility issues arising from different formats and structures of scientific data hinder progress in data generation, organization, storage, and sharing. To address these challenges, interoperability and efficient data access and analysis automation are crucial. The Semantic Web emerges as a powerful solution to overcome these obstacles.
Expanding and adapting Semantic Web technologies to the Materials Science domain can significantly enhance research outcomes by enabling the uniform consideration, integration, and analysis of heterogeneous data from diverse sources and formats. Implementing these technologies can improve the traceability and reproducibility of scientific procedures, experiments, and simulations. It also facilitates automatable data management solutions and empowers researchers to answer scientific inquiries using semantic queries. Moreover, machine learning methods can benefit from enhanced data completeness and coherence.
The primary objective of this workshop was to gather professionals in Semantic Web and in Materials Science and Engineering to show the recent advances in the use of Semantic Web technologies for Materials Science and Engineering, as well as provide a platform for discussing issues, finding collaboration opportunities and developing a community for this interdisciplinary field.
We thank all authors for their submissions and all members of the SeMatS program committee for their useful reviews and comments. We are also grateful to Daniel Garijo and Andrea Mannocci, the workshop chairs of SEMANTICS 2024, for their continuous support during the workshop organization.
T2 - SeMatS 2024 - The 1st International Workshop on Semantic Materials Science
CY - Amsterdam, The Netherlands
DA - 17.09.2024
KW - Materials science and engineering
KW - Semantic web
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:0074-3760-0
SN - 1613-0073
VL - 3760
SP - 1
EP - 127
PB - RWTH Aachen
CY - Aachen
AN - OPUS4-62497
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Ghnatios, C.
A1 - Robens-Radermacher, Annika
T1 - PGD in thermal transient problems with a moving heat source: A sensitivity study on factors affecting accuracy and efficiency
N2 - Thermal transient problems, essential for modeling applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting their applications, for example for model parameter estimation or online process control. Model order reduction, a solution to preserve the accuracy while reducing the computation time, is explored. This article addresses challenges in developing reduced order models using the proper generalized decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model’s performance and emphasize the importance of their consideration when implementing such models. For thermal example, it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model.
KW - Additive manufacturing
KW - Mapping for unseparable load
KW - Model order reduction (MOR)
KW - Thermal transient problem
KW - Sensitivity analysis
KW - Proper generalized decomposition (PGD)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598001
DO - https://doi.org/10.1002/eng2.12887
VL - 6
IS - 11
SP - 1
EP - 22
PB - John Wiley & Sons Ltd.
CY - Berlin
AN - OPUS4-59800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tamsen, Erik
T1 - From concrete mixture to structural design an optimization framework to reduce the global warming potential
N2 - Concrete has a long history in the construction industry and is currently one of the most widely used building materials. Unfortunately, the concrete industry has a significant impact on the environment by contributing to about 9% of the total anthropogenic greenhouse gas (GHG) emissions. Concrete is a highly complex composite material. However, the main source of concrete's GHG emissions is the cement. This leads to two main strategies when trying to reduce the environmental impact. The first is to reduce the cement within the concrete mix. This can be done by substituting it using additives or increasing the amount of aggregates. Usually this will lead to decreased material properties, like compressive strength or stiffness. The second option is to reduce the amount of required concrete by optimizing the topology of the structure. However, this might require higher compressive strength. In addition, there are other properties like to workability which need to be considered. All in all, this leads to a highly complex optimization problem, which requires the estimation of effective concrete properties, based on the mixture as input to a predictive simulation.
We present an automated workflow framework which combines experimental data with simulations, calibrates the simulation and performs the desired optimization. This workflow includes classical FE models, design guidelines based on model codes, as well as data driven methods. The chosen example is a beam, for which the concrete mixture is optimized to reduce GHG emissions. The first step is an estimation of material parameters, based on experimental data. This includes measures of stochastic distribution, allowing the quantification of the quality of the estimated parameters. The second step is the optimization. It takes into account constraints like the loading capacity after 28 days, the maximum allowed temperature during cement hydration and the maximum time till demoulding. The applied models include a Mori-Tanaka-based homogenization method to estimate effective concrete parameters, an FE simulation including the evolution of the concrete compressive strength and stiffness, the temperature field, displacements, and stress. This research shows a way towards a more performance-oriented material design.
T2 - M2P 2023 (First International Conference Math 2 Product)
CY - Taormina, Italy
DA - 30.05.2023
KW - Experimental data
KW - Simulations
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582545
AN - OPUS4-58254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krüger, Miriam E.
A1 - Hilbig, Harald
A1 - Stelzner, Ludwig
A1 - Machner, Alisa
T1 - Effect of the chemical composition of synthetic alkali-silica gels on their structure, swelling behavior and water uptake
N2 - For alkali-silica reaction (ASR) gels, the relationship between swelling expansion, structure and chemical composition, particularly the effect of aluminum, remains unknown. This study investigates the structure, swelling expansion and associated water uptake of synthetic ASR gels with various Al/Si (0–0.1) and Ca/Si (0.1–0.4) ratios. The results show that aluminum incorporated into the gel structure reduces the overall swelling expansion and the leaching of silicate species during the swelling test. Moreover, they revealed that water in the Al-ASR gels is more tightly bound, reducing the overall water uptake compared to the Al-free ASR gels. Additionally, there is a linear correlation between the maximal swelling results and the ASR gel composition.
However, no direct correlation emerged between the amount of water uptake and the free swelling of the ASR gels, which indicates that other factors, like the type of water bonding and pore size of the gels, are decisive for the swelling mechanism.
KW - Concrete
KW - Alkali-silica reaction (ASR)
KW - Durability
KW - 1H NMR relaxometry
KW - 29Si NMR
KW - 27Al NMR
KW - FTIR
KW - Al-ASR gel
KW - Swelling test
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624268
DO - https://doi.org/10.1016/j.cemconres.2024.107596
VL - 184
SP - 1
EP - 18
PB - Elsevier B.V.
AN - OPUS4-62426
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frei, Vivian
A1 - Pirskawetz, Stephan
A1 - Thiele, Marc
A1 - Rogge, Andreas
T1 - Ermüdungsverhalten von Beton für unterschiedliche Probekörpergeometrien
N2 - Die heute in der Anwendung befindlichen Bemessungskonzepte für Ermüdung von Beton stammen zum Teil noch aus den 1990er Jahren und sind speziell hinsichtlich hochfester Betone konservativ ausgelegt. Um die Vorteile von Türmen für Windkraftanlagen, vor allem auch aus hochfesten Betonen, im Zuge des geplanten Ausbaus der Windenergieversorgung in Deutschland wirtschaftlich nutzbar zu machen, müssen diese Bemessungskonzepte weiterentwickelt werden. Dafür sind umfangreiche Untersuchungen zur Ermittlung von Bruchlastwechselzahlen und zur Charakterisierung der Schädigungsentwicklung unter Ermüdungsbeanspruchung erforderlich. Allgemein anerkannte bzw. verbindliche Regelwerke oder Verfahren zur experimentellen Bestimmung der Ermüdungsfestigkeit (Bruchlastwechselzahlen) an Betonproben gibt es zurzeit aber nicht und die bisher durchgeführten Untersuchungen variieren in Parametern wie Probengeometrie, Probengröße und Prüffrequenz. Eine vergleichende Analyse der Ergebnisse der Studien und insbesondere die Übertragbarkeit auf bauteilrelevante Abmessungen ist auf dieser Grundlage nur sehr eingeschränkt möglich.
KW - Ermüdungsverhalten
KW - Probekörpergeometrien
KW - Druckschwellenversuch
KW - Bruchlastwechselzahlen
KW - Beton
PY - 2023
UR - https://www.betonverein.de/dbv-heft-52-materialermuedung-von-stahl-und-spannbeton-unter-hochzyklischer-beanspruchung-ergebnisse-des-verbundforschungsvorhabens-win-con-fat
IS - 52
SP - 19
EP - 22
PB - Deutscher Beton- und Bautechnik-Verein E.V.
CY - Berlin
AN - OPUS4-58746
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Villani, P.
A1 - Unger, Jörg F.
A1 - Weiser, M.
T1 - Adaptive Gaussian process regression for Bayesian inverse problems
N2 - We introduce a novel adaptive Gaussian Process Regression (GPR) methodology for efficient construction of surrogate models for Bayesian inverse problems with expensive forward model evaluations. An adaptive design strategy focuses on optimizing both the positioning and simulation accuracy of training data in order to reduce the computational cost of simulating training data without compromising the fidelity of the posterior distributions of parameters. The method interleaves a goal-oriented active learning algorithm selecting evaluation points and tolerances based on the expected impact on the Kullback-Leibler divergence of surrogated and true posterior with a Markov Chain Monte Carlo sampling of the posterior. The performance benefit of the adaptive approach is demonstrated for two simple test problems.
T2 - Algoritmy 2024 - Central-European Conference on Scientific Computing
CY - Vysoké Tatry, Slovakia
DA - 15.03.2024
KW - Active learning
KW - Bayesian inverse problems
KW - Gaussian Process Regression (GPR)
KW - Parameter identification
KW - Surrogate models
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600408
DO - https://doi.org/10.48550/arXiv.2404.19459
SN - 2331-8422
SP - 1
EP - 12
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-60040
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Werder, Julia
A1 - Simon, Sebastian
A1 - Gardei, André
A1 - Fontana, P.
A1 - Meng, Birgit
T1 - Thermal and hydrothermal treatment of UHPC: influence of the process parameters on the phase composition of ultra-high performance concrete
N2 - Several studies show that thermal and hydrothermal treatment can further improve the excellent properties of UHPC in terms of mechanical strength and durability. While for the thermal treatment the increase in strength is attributed to an intensified pozzolanic and hydraulic reaction, for the hydrothermal treatment previous studies accredited it mostly to the formation of tobermorite. In the presented study thermal and hydrothermal treatment of UHPC samples was systematically varied and the phase formation analysed related to the strength development of a reference sample cured for 28 days in water. For the thermal treatment the results show that the strength increase depends on the protection against desiccation and can be ascribed to an improved pozzolanic reaction of the siliceous fillers. To achieve a significant enhancement of strength, a pre-storage time of few days and a long dwell time at elevated temperature/pressure are required. For the hydrothermal treatment already heating the specimens up to 185 °C in saturated steam followed by an immediate cooling leads to a substantial increase in compressive strength. Pre-storage time did not affect the result as far as a minimum of several hours is guaranteed. The improved performance is due to an increase in the pozzolanic and hydraulic reaction. Surprisingly, tobermorite was only found within a very thin layer at the surface of the sample, but not in the bulk. Sulphate and aluminium stemming from the decomposition of the ettringite are bound in the newly formed phases hydroxylellestadite and hydrogarnet.
KW - UHPC
KW - Thermal treatment
KW - Hydrothermal treatment
KW - Compressive strength
KW - Phase development
KW - Durability
KW - Tobermorite
KW - Hydroxylellestadite
KW - Hydrogarnet
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523402
DO - https://doi.org/10.1617/s11527-021-01633-w
SN - 1871-6873
SN - 1359-5997
VL - 54
IS - 1
SP - Article 44
PB - Springer Nature
AN - OPUS4-52340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallau, Wilma
A1 - Recknagel, Christoph
T1 - Durability Assessment of Structural Sealant Glazing Systems applying a Performance Test Method
N2 - During the service life of a Structural Sealant Glazing (SSG) facade, its silicone bond is exposed to climatic, chemical, and mechanical loads. While current durability assessment methods schedule separate test programmes for accelerated weathering and fatigue, the presented test applies mechanical loading and weather cycling simultaneously to simulate 50 years of use. Specifically designed medium-scale system specimens resemble a common SSG-bond. Displacement-controlled sinusoidal load cycles in two load directions subject these specimens to tensile, compression and shear loads. Weathering comprises temperature and humidity cycles, UV-radiation, and application of water and detergent. During testing, the forces transmitted by the system specimens are continuously measured for performance assessment. The resulting system response reveals mechanical performance characteristics like elastic moduli and dissipated energies which decrease during exposure, indicating stress relaxation and degradation. Two common structural sealants were tested. After testing, sections of the system specimens were subjected to tensile and shear tests for mechanical characterisation. Strengths and moduli are notably reduced by combined loading compared to those of reference and weathered specimens. Hardness and visual inspections of the bond correlate with the performance and bond characteristics. The approach introduced in this article provides a basis for life cycle assessment of SSG-systems.
KW - Structural sealant glazing
KW - Cyclic weathering
KW - Mechanical loading
KW - Artificial ageing
KW - Durability assessment
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519172
DO - https://doi.org/10.1080/00218464.2020.1840985
VL - 98
IS - 5
SP - 464
EP - 487
PB - Taylor & Francis Group
AN - OPUS4-51917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
A1 - Bintz, Thilo
A1 - Heyn, R.
A1 - Hirsch, H.
A1 - Grunewald, J.
A1 - Kruschwitz, Sabine
T1 - Detailed investigation of capillary active insulation materials by 1H nuclear magnetic resonance (NMR) and thermogravimetric drying
N2 - Capillary active interior insulation materials are an important approach to minimize energy losses of historical buildings. A key factor for their performance is a high liquid conductivity, which enables redistribution of liquid moisture within the material. We set up an experiment to investigate the development of moisture profiles within two different interior insulation materials, calcium-silicate (CaSi) and expanded perlite (EP), under constant boundary conditions. The moisture profiles were determined by two different methods: simple destructive sample slicing with subsequent thermogravimetric drying as well as non-destructive NMR measurements with high spatial resolution. The moisture profiles obtained from both methods show good agreement, when compared at the low spatial resolution of sample slicing, which demonstrates the reliability of this method. Moreover, the measured T2-relaxation-time distributions across the sample depth were measured, which may give further insight into the saturation degree of the different pore sizes. In order to explain differences in the moisture profiles between CaSi and EP, we determined their pore-size distribution with different methods: conversion of the NMR T2 relaxationtime distribution at full saturation, mercury intrusion porosimetry and indirect determination from pressure plate measurements. CaSi shows a unimodal distribution at small pore diameters, while in EP, a bi-modal or wider distribution was found. We assume that the smaller pore diameters of CaSi lead to a higher capillary conductivity, which causes a more distributed moisture profile in comparison with that of EP.
T2 - NDT-CE
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Insulation material
KW - Nuclear magnetic resonance
KW - Capillary conductivity
KW - Pore-size distribution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579172
DO - https://doi.org/10.58286/27205
SN - 1435-4934
VL - 27
IS - 9
SP - 1
EP - 11
AN - OPUS4-57917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hirsch, T.
A1 - Voigt, Marieke
A1 - Lehmann, Christian
A1 - Meng, Birgit
A1 - Lothenbach, B.
T1 - Impact of autoclaving on the phase assemblage of Portland cement: Experiment and thermodynamic modelling
N2 - Even after autoclaving for 2 weeks in the temperature range of 120 to 200 °C, CEM I paste with a water-to-cement ratio of 0.5 still contains some low-crystalline C-S-H. The conversion of low-crystalline C-S-H to crystalline is faster with increasing temperature. The observed low-crystalline and crystalline C-S-H phases (reinhardbraunsite, jaffeite) indicate that the sampleshave not reached equilibrium yet under these experimental conditions. However, there is a good agreement between experiment and thermodynamic modelling for the other solids indicating that the used datasets are suitable for this application.
T2 - 16th International Congress on the Chemistry of cement 2023 - ICCC2023
CY - Bangkok, Thailand
DA - 18.09.2023
KW - Zement
KW - Thermodynamik
KW - Phasenzusammensetzung
KW - Mineralogie
KW - Modellierung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589779
UR - https://iccc2023.org
VL - 1
SP - 619
EP - 621
AN - OPUS4-58977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Signorini, C.
A1 - Bracklow, F.
A1 - Hering, Marcus
A1 - Butler, M.
A1 - Leicht, L.
A1 - Schubert, T.
A1 - Beigh, M. A. B.
A1 - Beckmann, B.
A1 - Curbach, M.
A1 - Mechtcherine, V.
T1 - Ballistic limit and damage assessment of hybrid fibre-reinforced cementitious thin composite plates under impact loading
N2 - Impact resistance of reinforced concrete (RC) structures can be significantly improved by strengthening RC members with thin composite layers featuring high damage tolerance. Indeed, to limit the well-known vulnerability of cement-based materials against impact loading, the synergistic effects of short fibres and continuous textile meshes as hybrid reinforcement has been proved to be highly beneficial. This paper addresses the characterisation of novel cement-based hybrid composites through accelerated drop-weight impact tests conducted on rectangular plates at different impact energies. Two distinct matrices are assessed, with particular interest in a newly developed limestone calcined clay cement (LC3)-based formulation. Important parameters quantifying energy dissipation capability, load bearing capacity and damage are cross-checked to compute the ballistic limit and estimate the safety-relevant characteristics of the different composites at hand. Although textiles alone can improve the damage tolerance of fine concrete to some extent, the crack-bridging attitude of short, well-dispersed fibres in hybrid composites imparts a certain ductility to the cement-based matrices, allowing a greater portion of the textile to be activated and significantly reducing the amount of matrix spalling under impact.
KW - Impact loading
KW - Cement-based composites
KW - SHCC
KW - TRC
KW - Sustainable binders
PY - 2023
DO - https://doi.org/10.1016/j.jobe.2023.108037
VL - 80
SP - 1
EP - 21
PB - Elsevier Ltd.
AN - OPUS4-58793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
T1 - Ermittlung der Porosität von Sandsteinen - Vergleich von Quecksilberporosimetrie, Tauchwägung und NMR
N2 - Die Porosität sowie die Porengrößenverteilung (PSD) eines Baustoffs sind wichtige petrophysikalische Eigenschaften, die Transportprozesse im Material beeinflussen und im direkten Zusammenhang mit der Schadensanfälligkeit stehen (Frost-Tau-Schäden, Schäden durch Salzeinträge und sauren Regen). Verfahren zur Ermittlung der Porosität stellen die Quecksilberporosimetrie (MIP), das Prinzip der Tauchwägung nach Archimedes (triple weighing method, TWM) und die Nuklear Magnetische Resonanz (NMR) dar.
Das Hauptziel dieser Arbeit ist der Vergleich der drei Methoden für die Porositätsbestimmung. Als Untersuchungsmaterial wurde Sandstein gewählt. Als Baustoff wird Sandstein trotz einer teilweise geringen Festigkeit, aber aufgrund seiner Farbvielfalt häufig für Kulturbauten, Gehwegmaterial und Fassaden eingesetzt. Sandsteine weisen zudem meist eine hohe effektive Porosität (bis zu ca. 30 %) und teilweise breite Porengrößenspektren auf, wodurch Feuchte- und Ioneneinträge begünstigt werden und zu z. B. langfristigen Verfärbungen an Sandsteinfassaden führen können.
Im Rahmen dieser Arbeit werden die Porositäten von 10 verschiedenen Sandsteinen aus Deutschland und Tschechien bestimmt. Für die Untersuchungen mittels TWM und NMR wurden für jede Sandsteinart zwei zylinderförmige Proben unter Unterdruck mit Leitungswasser aufgesättigt. Beim Vergleich der Verfahren liegt der Fokus insbesondere auf NMR und der verwendeten Gerätetechnik, die mit einer minimalen Echozeit von 50 µs ein Wasserstoffsignal in Sandsteinen aus bis zu ca. 2 nm kleine Poren erfassen kann. Darüber hinaus wird das Auflösungsvermögen von MIP und NMR bezüglich der Poren- bzw. Poreneingangsgrößen diskutiert. Für den Vergleich von NMR und MIP werden an ausgewählten Sandsteinproben ebenfalls die zusätzlich ermittelten PSD in Korrelation zueinander gebracht.
Erste Ergebnisse zeigen eine gute Korrelation von NMR- und TWM-Daten, aber teilweise starke Abweichungen zu den mit MIP bestimmten Porositäten. Ergebnisse zu den PSD zeigen teilweise nahezu identische Kurvenverläufe. Jedoch ist die Abschätzung des Umrechnungsfaktors für die NMR-Daten ohne Hinzuziehen von zusätzlichen Referenzverfahren wie Röntgen-Computer-Tomographie oder Spektral Induzierte Polarisation teilweise sehr schwierig.
T2 - Bauwerksdiagnose
CY - Berlin, Germany
DA - 13.02.2020
KW - NMR
KW - Porosität
KW - Sandsteine
KW - Quecksilberporosimetrie
KW - Tauchwägung
PY - 2020
N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M.
AN - OPUS4-50405
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
T1 - Ermittlung des Flüssigwasseranteils an voll- und teilgesättigten Sandsteinen mittels 1H-NMR und Hygrometrie
N2 - Da Feuchte insbesondere in Form von Flüssigwasser ein hohes Schadenspotential für Baustoffe und Konstruktionen darstellt, finden zerstörungsfreie Verfahren wie die Kernspinresonanz (NMR) zunehmend Einsatz im Bauwesen. Auch wenn zur qualitativen Lokalisierung möglicher Schad- und Risikostellen bereits zahlreiche zerstörungsfreie Verfahren in der Praxis Anwendung finden, so besteht beispielweise bei der Porenraumcharakterisierung und dem Verständnis von Feuchtetransportmechanismen weiterhin Forschungsbedarf. Eine besondere Herausforderung stellt in diesem Zusammenhang die (ortsaufgelöste) Erfassung und Quantifizierung von Feuchteverteilungen bei Teilsättigung dar.
Mittels 1H-NMR lassen sich der Wassergehalt sowie die Relaxationszeiten der Wasserstoffprotonen in Abhängigkeit von ihrer Bindungsart und der Porenumgebung messen. In vollgesättigten porösen Baustoffen kann somit das NMR-Signal als Porengrößenverteilung interpretiert werden. Da aber in der Praxis nur selten bis nie vollgesättigte Zustände vorliegen, befasst sich eine laufende Forschungsarbeit mit dem Verständnis der NMR-Signale teilgesättigter Porensysteme, die teilweise multimodale Porengrößenverteilungen aufweisen.
Im Rahmen dieser Arbeit werden insgesamt 19 Sandsteine aus Deutschland, Tschechien und Italien sowohl im voll- als auch im teilgesättigten Zustand mit NMR untersucht. Definierte teilgesättigte Zustände werden durch Aufsättigen der Proben in Exsikkatoren mit verschiedenen relativen Luftfeuchten (z. B. 33 %, 75 %, 96%) erzeugt. Die Regulierung der Luftfeuchten erfolgt mit Hilfe von gesättigten Salzlösungen. Als Ergebnis wird die Veränderung der Signalamplitude und der T2-Relaxationszeitenverteilungen in Abhängigkeit von dem Feuchtezustand näher betrachtet. Des Weiteren erfolgt die Berechnung des Flüssigwasseranteils bzw. der adsorbierten Wasserfilmdicke einzelner Poren aus der mit Quecksilberporosimetrie bestimmten Porengrößenverteilung und der Annahme einer Porengeometrie (z.B. Schlitz-, Zylinderpore, etc.). Am Ende dieser Arbeit soll der Zusammenhang des NMR-Signals (Amplitude und Relaxationszeiten) mit dem Porensättigungsgrad in einem Porensystem mit multimodaler Porengrößenverteilung bei Teilsättigung aufgezeigt werden.
T2 - Jahrestagung der Deutschen Geophysikalischen Gesellschaft
CY - Online meeting
DA - 18.05.2020
KW - NMR
KW - Sandstein
KW - Flüssigwasser
KW - Teilsättigung
KW - Hygrometrie
PY - 2020
N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M.
AN - OPUS4-50861
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wiehle, Philipp
T1 - Feuchteverhalten von Lehmsteinmauerwerk unter natürlichen Klimabedingungen
N2 - Druckfestigkeit und Elastizitätsmodul von Lehmsteinmauerwerk nehmen mit steigendem Feuchtegehalt ab, weswegen die Mauerwerksdruckfestigkeit bei der Bemessung gemäß DIN 18940 in Abhängigkeit der maximal zu erwartenden Ausgleichsfeuchte abgemindert wird. Da bisher allerdings keine Messdaten zum Feuchtegehalt von Lehmsteinmauerwerk unter natürlichen Klimabedingungen vorliegen, stellen die normativen Grenzwerte lediglich eine konservative Abschätzung dar. Um die Feuchtegehalte von Lehmsteinmauerwerk und somit die Tragfähigkeit realitätsnah einschätzen zu können, wurden im Rahmen der vorliegenden Arbeit sowohl experimentelle als auch numerische Untersuchungen zum feuchtetechnischen Verhalten durchgeführt. Dabei wurden erstmalig magnetresonanzspektroskopische Untersuchungen an tragenden Lehmsteinen unterschiedlicher Herstellungsmethoden angewandt Weiterhin wurden Luftfeuchtesensoren in Lehmsteinmauerwerk eingebettet, um hygrische Langzeitfeuchtemessungen unter natürlichen Klimabedingungen durchzuführen. Auf Basis dieser Erkenntnisse wurde schließlich ein numerisches Modell kalibriert und Parameterstudien durchgeführt, um den unter realen Klimabedingungen tatsächlich auftretenden Feuchtegehalt im Lehmmauerwerk sowie dessen Verteilung über den Querschnitt einschätzen zu können und die normativen Grenzwerte zu überprüfen.
Gezeigt wurde, dass die realitätsnahe instationäre Berechnung des Feuchtetransports mit üblichen hygrothermischen Simulationsprogrammen auf Basis einfacher feuchtetechnischer Kennwerte auch bei Lehmbaustoffen möglich ist. Der Einfluss des Quellens und Schwindens der enthaltenen Tonminerale und organischen Bestandteile wurde durch eine Modifikation bei der Ermittlung des Wasseraufnahmekoeffizienten explizit berücksichtigt und ist somit auch in den daraus abgeleiteten Transportkoeffizienten enthalten. Darüber hinaus wurde die Feuchtespeicherfunktion im überhygroskopischen Bereich auf Grundlage der Porenvolumenverteilung abgeschätzt. Die Approximation der Transportkoeffizienten und der Feuchtespeicherfunktion stellt dabei eine wesentliche Vereinfachung für Lehmbaustoffe dar, da ihre experimentelle Bestimmung aufgrund des Kontaktes mit Flüssigwasser kaum möglich ist.
In Bezug auf das Feuchteverhalten üblicher Außenwandaufbauten von Wohnräumen konnte festgestellt werden, dass die Ausgleichsfeuchte im Lehmsteinmauerwerk stets unterhalb des in Nutzungsklasse 1 gemäß DIN 18940 zulässigen Grenzwertes von 65 % liegt. Je nach Putzsystem und Dämmstoff reduziert sich die Ausgleichsfeuchte auf Werte unter 60 %, wobei sich eine annähernd gleichmäßige Verteilung der Feuchte über den Mauerwerksquerschnitt hinweg einstellt.
Bei Außenwänden von unbeheizten Räumen ergab sich eine maximale Ausgleichsfeuchte, die über weite Teile des Querschnitts unterhalb von 80 % lag. Der Ansatz einer maximalen Ausgleichsfeuchte von 90 % in Nutzungsklasse 2 ist folglich zu hoch angesetzt. Die zulässige Ausgleichsfeuchte bzw. der Umgebungsfeuchtefaktor in Nutzungsklasse 2 sollte dementsprechend angepasst werden.
T2 - LEHM 2024 - 9. Internationale Fachtagung für Lehmbau
CY - Weimar, Germany
DA - 27.09.2024
KW - Lehm
KW - Mauerwerk
KW - Feuchte
KW - Tragverhalten
KW - Bemessung
PY - 2024
AN - OPUS4-61904
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz M.
A1 - Salvalaglio, Matteo
A1 - Wallace, Adam F.
A1 - De Yoreo, James J.
T1 - The Birth of Minerals: From Single Step to Multiple Step Mechanisms
N2 - Mineral formation from ions in aqueous solutions begins with complex initial stages, where amorphous and liquid-like precursors play pivotal roles before crystalline growth occurs. Both classical and non-classical nucleation and growth theories, introduced in previous chapters, offer explanations, each with their own strengths and limitations, for the complex intermediate phases observed in experimental research. Analytical techniques play a critical role in detecting and characterizing precursor phases, offering valuable insights into nucleation and growth mechanisms across various temporal and spatial scales. Molecular dynamics and modelling provide in-depth perspectives on these phases, allowing for a closer examination of their nucleation and growth mechanisms at the molecular level, and revealing the intricate processes that govern their behaviour.
KW - Crystallisation
KW - Nucleation
KW - Synchrotron
KW - Thermodynamics
KW - Minerals
PY - 2025
DO - https://doi.org/10.2138/gselements.21.1.25
SN - 1811-5217
VL - 21
IS - 1
SP - 25
EP - 32
PB - Mineralogical Society of America
AN - OPUS4-62841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - McGonigle, Rebecca
A1 - Glasgow, Jodie
A1 - Houston, Catriona
A1 - Cameron, Iain
A1 - Homann, Christian
A1 - Black, Dominic J.
A1 - Pal, Robert
A1 - MacKenzie, Lewis E.
ED - MacKenzie, Lewis E.
T1 - Autoclave reactor synthesis of upconversion nanoparticles, unreported variables, and safety considerations
N2 - Autoclave reactors are widely used across chemical and biological sciences, including for the synthesis of upconversion nanoparticles (UCNPs) and other nanomaterials. Yet, the details of how autoclave reactors are used in such synthesis are rarely reported in the literature, leaving several key synthesis variables widely unreported and thereby hampering experimental reproducibility. In this perspective, we discuss the safety considerations of autoclave reactors and note that autoclaves should only be used if they are (a) purchased from reputable suppliers/manufacturers and (b) have been certified compliant with relevant safety standards. Ultimately, using unsuitable autoclave equipment can pose a severe physical hazard and may breach legal safety requirements. In addition, we highlight several parameters in autoclave synthesis that should be reported as standard to maximise the reproducibility of autoclave synthesis experiments across materials and chemistry research. We encourage users of autoclave synthesis vessels to: (1) adopt high-safety autoclaves and (2) report the many experimental variables involved to enhance experimental reproducibility.
KW - Reference material
KW - Nano
KW - Particle
KW - Shell
KW - Fluorescence
KW - Lifetime
KW - Decay kinetics
KW - Synthesis
KW - Quality assurance
KW - Method
KW - Energy transfer
KW - Upconversion
KW - Autoclave synthesis
KW - Data comparability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625672
DO - https://doi.org/10.1038/s42004-025-01415-3
VL - 8
IS - 1
SP - 1
EP - 7
PB - Springer Science and Business Media LLC
AN - OPUS4-62567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Alphonse, Amal
A1 - Hintermüller, Michael
A1 - Kister, Alexander
A1 - Lun, Chin Hang
A1 - Sirotenko, Clemens
T1 - A neural network approach to learning solutions of a class of elliptic variational inequalities
N2 - We develop a weak adversarial approach to solving obstacle problems using neural networks. By employing (generalised) regularised gap functions and their properties we rewrite the obstacle problem (which is an elliptic variational inequality) as a minmax problem, providing a natural formulation amenable to learning. Our approach, in contrast to much of the literature, does not require the elliptic operator to be symmetric. We provide an error analysis for suitable discretisations of the continuous problem, estimating in particular the approximation and statistical errors. Parametrising the solution and test function as neural networks, we apply a modified gradient descent ascent algorithm to treat the problem and conclude the paper with various examples and experiments. Our solution algorithm is in particular able to easily handle obstacle problems that feature biactivity (or lack of strict complementarity), a situation that poses difficulty for traditional numerical methods.
KW - Obstacle Problems
KW - Numerical Analysis
KW - Optimization and Control
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622160
DO - https://doi.org/10.48550/arXiv.2411.18565
SP - 1
EP - 38
AN - OPUS4-62216
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bulling, Jannis
T1 - On the efficient simulation of ultrasonic waves on polygonal meshes
N2 - At many stages of technology development in ultrasonic Non-Destructive Testing (NDT) and Structural Health Monitoring (SHM), simulation tools are essential. Many modern approaches to ultrasonic testing, such as Model Assisted Probability of Detection, inverse problems with iterative optimization, or the generation of data for AI training, benefit from highly effcient simulation tools in terms of simulation time. In this talk, we investigate explicit time stepping with the Scaled Boundary Finite Element Method (SBFEM) for approximating the linear elastic wave equation on 2D polygonal meshes, enhanced with a mass lumping technique for faster simulation times. We present the proposed changes to the formulation to successfully use mass lumping. Examples are used to demonstrate that there is no loss of quality due to the approximated mass matrix. Furthermore, mass lumping reduces the simulation time and makes the simulation more effcient. In addition, the proposed simulation method has the advantages of SBFEM meshing techniques. These advantages include fast meshing using an image-based quadtree algorithm or polygonal meshing by transforming triangular meshes based on a CAD model. The latter meshing method can include special crack tip elements that effciently handle the crack tip singularity.
T2 - DAS | DAGA 2025
CY - Copenhagen, Denmark
DA - 17.03.2025
KW - Non-Destructive Testing (NDT)
KW - Scaled Boundary Finite Element Method (SBFEM)
KW - Structural Health Monitoring (SHM)
PY - 2025
AN - OPUS4-63016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bulling, Jannis
A1 - Gravenkamp, H.
A1 - Birk, C.
T1 - On the efficient simulation of ultrasonic waves on polygonal meshes
N2 - At many stages of technology development in ultrasonic Non-Destructive Testing (NDT) and Structural Health Monitoring (SHM), simulation tools are essential. Many modern approaches to ultrasonic testing, such as Model Assisted Probability of Detection, inverse problems with iterative optimization, or the generation of data for AI training, benefit from highly efficient simulation tools in terms of simulation time. In this talk, we investigate explicit time stepping with the Scaled Boundary Finite Element Method (SBFEM) for approximating the linear elastic wave equation on 2D polygonal meshes, enhanced with a mass lumping technique for faster simulation times. We present the proposed changes to the formulation to successfully use mass lumping. Examples are used to demonstrate that there is no loss of quality due to the approximated mass matrix. Furthermore, mass lumping reduces the simulation time and makes the simulation more efficient. In addition, the proposed simulation method has the advantages of SBFEM meshing techniques. These advantages include fast meshing using an image-based quadtree algorithm or polygonal meshing by transforming triangular meshes based on a CAD model. The latter meshing method can include special crack tip elements that efficiently handle the crack tip singularity.
T2 - DAS | DAGA 2025
CY - Copenhagen, Denmark
DA - 17.03.2025
KW - Non-Destructive Testing (NDT)
KW - Scaled Boundary Finite Element Method (SBFEM)
KW - Structural Health Monitoring (SHM)
KW - Numerical simulation
PY - 2025
UR - https://pub.dega-akustik.de/DAS-DAGA_2025/imprint.html
SN - 978-3-939296-23-2
SP - 1592
EP - 1595
AN - OPUS4-63017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bintz, Thilo
A1 - Kruschwitz, Sabine
T1 - Non-destructive Testing for the Determination of Durability-Relevant Material Properties of Clinker-Reduced Building Materials
N2 - In the quest to combat climate change, the construction industry, heavily reliant on cement-based materials, faces scrutiny due to significant CO2 emissions, mainly from clinker production. To address this, there’s a need to strategically reduce clinker content in cement. However, these new formulations must meet the same requirements as the original ones, so their durability must be investigated. In this study, we determined material parameters that enable an assessment of moisture and ion transport. These methods offer advantages over conventional approaches, including non-destructiveness, reduced measurement time, simplified setup, enhanced resolution, and improvement of detection limits. Our investigation utilizes NDT techniques, using 1H NMR relaxometry for moisture transport and LIBS for ion transport in various clinker-reduced materials. The NMR tomograph provides spatial insights into internal moisture transport, correlated with weight change assessments for the capillary transport coefficient. Additionally, based on NMR relaxometry data the chloride diffusion coefficient is estimated. Chloride migration tests are performed, and results are evaluated using LIBS and indicator tests for the chloride migration coefficient. Our findings highlight NMR relaxometry and LIBS advantages over conventional methods, showcasing superior spatial resolution, non-destructiveness, and, in some cases, expedited results with independence from the formulation of the cement matrix. Thus, these new methods can be used to test the durability of new, more heterogeneous cementbased building.
T2 - Rilem Spring Convention 2024
CY - Milano, Italy
DA - 10.04.2024
KW - NMR relaxometry
KW - LIBS
KW - Clinker reduced cement
KW - Durability parameters
PY - 2025
SN - 978-3-031-70281-5
DO - https://doi.org/10.1007/978-3-031-70281-5_48
VL - 56
SP - 426
EP - 434
AN - OPUS4-61824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poka, Konstantin
A1 - Ali, Sozol
A1 - Saeed, Waleed
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Quality assurance via a cyber physical system of a PBF-LB/M machine
N2 - Powder Bed Fusion with Laser Beam of Metals (PBF-LB/M) faces challenges in reproducibility and quality assurance, even for widely applied alloys like AlSi10Mg. This work introduces a digital provenance framework for PBF-LB/M, showcased through the EOS M 300–4 multi-laser machine. An Extract, Transform, Load (ETL) pipeline autonomously captures machine data, including scan vectors as well as process signals, and organizes them into a Digital Shadow (DS). The DS is further extended by external data sources, such as Melt Pool Monitoring (MPM), to enable comprehensive analysis and root cause identification. This approach ensures continuous data representation and facilitates the development of new quality metrics. Moreover, the framework enhances quality assurance and traceability, supports compliance with industry standards, and improves productivity. It also enables more precise cost calculations and predictive maintenance. By addressing these challenges, the framework is essential for advancing PBF-LB/M in industrial applications, achieving greater consistency and scalability in production.
KW - PBF-LB/M
KW - Data driven quality assurance
KW - Data engineering
KW - Digital shadow
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625187
DO - https://doi.org/10.1007/s40964-025-00978-w
SN - 2363-9520
VL - 10
IS - 3
SP - 1771
EP - 1783
PB - Springer Science and Business Media LLC
AN - OPUS4-62518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
T1 - Anwendung von KI für die Materialoptimierung im Bauwesen
N2 - Diese Arbeit untersucht den Einsatz von Künstlicher Intelligenz (KI) in der Materialentwicklung für Beton, mit einem Fokus auf Karbonatisierungswiderstand, CO₂-Reduktion und Kostenoptimierung. Das KI-Tool SLAMD, das auf inverses Materialdesign setzt, konnte in Studien die Entwicklungszeit für Betonmischungen um bis zu 80 % verkürzen. Durch die Integration zusätzlicher 1H-Kernspinresonanz-Daten wurde der Prozess um weitere 40 % beschleunigt. Insgesamt zeigt sich, dass der Einsatz von KI die Effizienz und Nachhaltigkeit in der Materialentwicklung signifikant steigern kann.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Cement & Concrete
KW - SLAMD app
KW - Nuclear magnetic
KW - Resonance
KW - Carbonation resistance
PY - 2024
AN - OPUS4-61423
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Buchheim, Janine
A1 - Recknagel, Christoph
A1 - Wolter, Patrick
A1 - Kittler-Packmor, Kai
T1 - A new approach towards scientific evaluation and performance-related design of bituminous joint sealing materials and constructions
N2 - While there is a permanent improvement of concrete pavement mixtures and pavement construction types over the last decades, the state-of-the-art joint sealing materials and joint constructions seem to stagnate on an antiquated empirical level. This status has been reaffirmed in the latest European standard. The consequences in the motorway network due to unsatisfying capability and durabilty of joint sealing systems are unacceptable. In addition, inadequate traffic performance (noise emissions, roll-over comfort) and traffic safety losses in the joint area of concrete pavements are existing challenges. These deficits and weaknesses reflect a demand for joint sealing materials and constructions whose approval requirements take functional aspects into account. Furthermore a sufficient analysis of decisive loads and a practice-oriented method to evaluate the requirements towards performance and durability is still missed. In this contribution decisive loads to German highways are analyzed. The design of test specimen for representative functional testing of joint sealing systems is discussed. The focus is on the geometry of the test specimens and the used concrete mixture. Finally, a new approach for a function-orientated test concept that considers representative load functions is presented. The potential of this approach to validate the durability and capability of various joint sealing systems is also presented using an example.
T2 - RILEM International Symposium on Bituminous Materials
CY - Online meeting
DA - 08.06.2020
KW - Joint sealing
KW - Expansion joint
KW - Performance testing
KW - Capability
KW - Durability
PY - 2020
SN - 978-3-030-46454-7
VL - 27
SP - 1
EP - 6
PB - Springer Nature
AN - OPUS4-53488
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
A1 - Telong, Melissa
A1 - Grobla, Lili
A1 - Schumacher, Katrin
A1 - Völker, Christoph
A1 - Yared, Kaleb
A1 - Kruschwitz, Sabine
ED - Ferrara, Liberato
ED - Muciaccia, Giovanni
ED - di Summa, Davide
T1 - Study on the Predictability of Carbonation Resistance of Cementitous Materials Based on NMR Features and the Use of SLAMD
N2 - This study explores the acceleration of material design in the concrete
industry, focusing on improving carbonation resistance, a key factor in the durability of concrete structures. Traditional tests for carbonation resistance are lengthy, but with the construction industry aiming for sustainable production, finding a balance between carbonation resistance and CO2 footprint is crucial. Our research
employs two innovative methods:
1. Applying the Sequential Learning App for Materials Discovery (SLAMD), an
AI materials design framework, to an extensive dataset of real-world concrete
compositions to selectively test materials that meet market demands: maximum
durability, optimal eco-durability, and the best cost-durability trade-off.
2. Investigating 1H Nuclear Magnetic Resonance (NMR) relaxometry as a quick
alternative for characterizing carbonation behavior, as it saves time compared
to traditional tests and assesses the complete material’s pore space. Specific
NMR features are then integrated into the material design model, with the
model’s performance compared against traditional approaches.
The results of our study are compelling, demonstrating that materials can
be precisely tailored to meet specific requirements with minimal data points. This marks a significant stride in the concrete industry, indicating thatNMR-based, lowfidelity surrogate characterizations, combined with a focused, data-driven design approach, can substantially accelerate the development of durable, sustainable concrete mixtures.
T2 - 4 RILEM Spring Convention and Conference on advanced construction materials and processes for a carbon neutral society 2024
CY - Milano, Italy
DA - 07.04.2024
KW - Nuclear magnetic resonance
KW - carbonation resistance
KW - cement and concrete
KW - SLAMD app
KW - predictability
PY - 2024
DO - https://doi.org/10.1007/978-3-031-70281-5_49
VL - 2
SP - 435
EP - 442
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-61692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Diercks, Philipp
T1 - Multiscale modeling of heterogeneous structures based on a localized model order reduction approach
N2 - Many of today’s problems in engineering demand reliable and accurate prediction of failure mechanisms of mechanical structures. Thus, it is necessary to take into account the heterogeneous structure on the smaller scale, to capture the underlying physical phenomena. However, this poses a great challenge to the numerical solution since the computational cost is significantly increased by resolving the smaller scale in the model. Moreover, in applications where scale separation as the basis of classical homogenization schemes does not hold, the influence of the smaller scale on the larger scale has to be modelled directly. This work aims to develop an efficient concurrent methodology to model heterogeneous structures combining the variational multiscale method (VMM) [1] and model order reduction techniques (e. g. [2]). First, the influence of the smaller scale on the larger scale can be taken into account following the additive split of the displacement field as in the VMM. Here, also a decomposition of the global domain into subdomains, each containing a fine grid discretization of the smaller scale, is introduced. Second, local reduced approximation spaces for the smaller scale solution are constructed by exploring possible solutions for each subdomain based on the concept of oversampling [3]. The associated transfer operator is approximated by random sampling [4]. Herein, we propose to incorporate the actual physical behaviour of the structure of interest in the training data by drawing random samples from a multivariate normal distribution with the solution of a reduced global problem as mean. The local reduced spaces are designed such that local contributions of each subdomain can be coupled in a conforming way. Thus, the resulting global system is sparse and reduced in size compared to the direct numerical simulation, leading to a faster solution of the problem.
T2 - ECCOMAS YIC
CY - Porto, Portugal
DA - 19.06.2023
KW - Multiscale Method
KW - Variational Multiscale Method
KW - Domain Decomposition
KW - Model Order Reduction
PY - 2023
AN - OPUS4-58251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andrés Arcones, Daniel
T1 - Evaluation of Model Bias Identification Approaches Based on Bayesian Inference and Applications to Digital Twins
N2 - In recent years, the use of simulation-based digital twins for monitoring and assessment of complex mechanical systems has greatly expanded. Their potential to increase the information obtained from limited data makes them an invaluable tool for a broad range of real-world applications. Nonetheless, there usually exists a discrepancy between the predicted response and the measurements of the system once built. One of the main contributors to this difference in addition to miscalibrated model parameters is the model error. Quantifying this socalled model bias (as well as proper values for the model parameters) is critical for the reliable performance of digital twins. Model bias identification is ultimately an inverse problem where information from measurements is used to update the original model. Bayesian formulations can tackle this task. Including the model bias as a parameter to be inferred enables the use of a Bayesian framework to obtain a probability distribution that represents the uncertainty between the measurements and the model. Simultaneously, this procedure can be combined with a classic parameter updating scheme to account for the trainable parameters in the original model. This study evaluates the effectiveness of different model bias identification approaches based on Bayesian inference methods. This includes more classical approaches such as direct parameter estimation using MCMC in a Bayesian setup, as well as more recent proposals such as stat- FEM or orthogonal Gaussian Processes. Their potential use in digital twins, generalization capabilities, and computational cost is extensively analyzed.
T2 - 5th ECCOMAS Thematic Conference on Uncertainty Quantificationin Computational Sciences and Engineering
CY - Athens, Greece
DA - 12.06.2023
KW - Digital Twin
KW - Simulation Models
KW - Uncertainty Quantification
KW - Model Bias
PY - 2023
UR - https://2023.uncecomp.org/
AN - OPUS4-58226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen‑Wiegart, Yu‑chen Karen
A1 - Huber, Norbert
A1 - Yager, Kevin G.
T1 - Machine learning approaches for intentional materials engineering
N2 - The development of nanoporous metals and metallic composites through dealloying processes presents significant opportunities in materials engineering. However, designing multicomponent precursor alloys and establishing corresponding processing methods that yield predictable compositions and nanostructures remain a complex challenge. This article explores how machine learning (ML)-augmented computational and experimental methodologies can tackle these challenges by predicting precursor alloy compositions, final nanoporous structures, and mechanical properties, while integrating ML-enabled autonomous experimentation for material design and quantification. We highlight recent advancements in applying ML to nanostructured materials design via dealloying and discuss how techniques from other nanomaterial designs can be adapted for improved control over morphological and compositional outcomes in nanoporous and nanocomposite materials. Furthermore, we explore the role of ML in autonomous synchrotron x-ray experimentation, enabling real-time feedback between modeling and experimental setups. ML-driven approaches to microstructure characterization and mechanical property prediction are also examined, with a focus on modeling and advanced imaging techniques such as three-dimensional nanotomography.
Finally, this article outlines future directions for ML-enhanced materials science, emphasizing the exploration of high-dimensional parameter spaces and the incorporation of materials kinetics into processing and property evaluation, ultimately advancing the design of nanoporous structures and materials science.
KW - Artificial intelligence
KW - Autonomous
KW - Nanostructure
KW - X-ray tomography
KW - Mechanical properties
PY - 2025
DO - https://doi.org/10.1557/s43577-025-00908-9
SN - 1938-1425
VL - 50
IS - 5
SP - 1
EP - 12
PB - Springer Nature
CY - London
AN - OPUS4-63160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
T1 - Non-destructive testing application examples using the NMR core-analyzing tomograph
N2 - Nuclear magnetic resonance (NMR) with focus on 1H protons is increasingly applied for non-destructive testing applications. Besides mobile NMR, laboratory devices such as the NMR core-analyzing tomograph are used. As their magnetic field is more homogeneous, they enable measurements with higher signal-to-noise ratios (SNR), but with limited sample sizes. The tomograph presented here (8.9 MHz) was constructed for a maximum sample diameter of 70 mm and length of up to 1 m. The resolution, the echo time (min. 50 µs), the SNR and the measurement type can be adjusted by means of exchangable coils. The tomograph enables measurements along the complete sensitive length, slice-selective and even 2- or 3-dimensional measurements. A movable sample lifting system thereby allows a precise positioning of the sample.
T2 - Magnetic Resonance in Porous Medie (MRPM) 2022
CY - Online meeting
DA - 21.08.2022
KW - Spalling
KW - Nuclear magnetic resonance
KW - Tomography
KW - Moisture transport
KW - Frost salt attach
PY - 2022
AN - OPUS4-55828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kempf, A.
T1 - Einfluss der Porosität auf die Duktilitätseigenschaften von additiv gefertigtem AlSi10Mg
N2 - Die Werkstoffeigenschaften im selektiven Laserstrahlschmelz-Verfahren hergestellter Bauteile werden von einer Vielzahl technologischer Parameter beeinflusst, sodass sich die Fertigungsgüte verschiedener Anlagen voneinander unterscheiden kann. Vor diesem Hintergrund wurde in der vorliegenden Arbeit untersucht, inwiefern sich durch verschiedene nachgelagerte Wärmebehandlungen die Mikrostruktur und die quasistatischen Festigkeitseigenschaften von Proben aus der Aluminiumlegierung AlSi10Mg, die mit verschiedenen Anlagen, Pulvern, Belichtungsstrategien und Prozessparametern gefertigt wurden, harmonisieren lassen. Die Versuche zeigten u.a., dass die erheblichen Festigkeitsunterschiede im Ausgangszustand unabhängig von der angewendeten Wärmebehandlungsroute aufgehoben wurden. Dennoch wurden signifikante Unterschiede in der Duktilität ermittelt. Anhand umfangreicher Bruchflächenanalysen konnte nachgewiesen werden, dass die in der Bruchfläche ermittelte Porosität eine lineare Korrelation zu der Bruchdehnung aufwies.
T2 - 5. Tagung des DVM-Arbeitskreises Additiv gefertigte Bauteile und Strukturen
CY - Online meeting
DA - 04.11.2020
KW - Duktilität
KW - Additive Fertigung
KW - Laser powder bed fusion
KW - AlSi10Mg
KW - Festigkeit
PY - 2020
AN - OPUS4-51656
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - AI/ML starts with data, …a practical example
N2 - A brief introduction to the efforts we have done in our lab towards AI/ML analysis of SAXS data. For this, we need to extend the data with an extensive, structured hierarchy of metadata and associated data. A practical look into the information stored in our files, and the organization of the files in a data catalog is presented.
T2 - Benchmarking for AI for Science at the Exascale A2 Workshop for Materials Science
CY - Online meeting
DA - 23.11.2020
KW - Small angle scattering
KW - Machine learning
KW - Data organization
KW - Data curation
KW - Metadata structuring
PY - 2020
AN - OPUS4-51660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Simkin, Roman
T1 - Identifying the initial corrosion fatigue failure based on dropping electrochemical potential
N2 - The corrosion fatigue of duplex stainless-steel X2CrNiMoN22-5-3 can be determined by purely alternating axial cyclic load to failure using hour-glass shaped specimens. The experimental setup comprises a corrosion chamber allowing for the circulation of an aquifer electrolyte heated to 369 K simulating a carbon capture and storage as well as geothermal power plant environment. During engineering of a carbon storage site or geothermal power plant, it may be crucial to determine the failure onset of a component beforehand. Therefore, an algorithm with 93.3% reliability was established based on splitting the measured potential values into ten time series with a capacity of ten values. The failure of corrosion fatigue specimens in a geothermal environment correlates to the drop of the curves of the electrochemical potential which is measured simultaneously within the corrosion chamber. Crack initiation was, therefore, successfully derived from the electrochemical potential.
KW - Corrosion fatigue
KW - Surface corrosion
KW - CO2
KW - Crack initiation
KW - Geothermal energy production
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629310
DO - https://doi.org/10.3390/app15010403
SN - 2076-3417
VL - 15
IS - 1
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-62931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Crevice corrosion of 304 stainless steel under the influence of chlorine and chloride
N2 - Der Einfluss von elektrolytisch erzeugten Desinfektionsmitteln auf die Spaltkorrosion des nichtrostenden Stahls 1.4301 wird dargestellt. Der Einfluss der Chlor- und Chloridkonzentration wird ermittelt
N2 - The influence of electrolytically produced disinfectants on crevice corrosion of 304 stainless steel is shown. The influence of chlorine and chloride concentrations is determined.
T2 - Kormat 2020
CY - Online meeting
DA - 26.11.2020
KW - Crevice corrosion
KW - Werkstoffe
KW - Stainless steel
KW - Disinfection
PY - 2020
AN - OPUS4-51698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
T1 - Betriebsfestigkeit von Struktur-Klebungen im Anwendungsgebiet der CS22
N2 - Moderne Segelflugzeuge sind voll-verklebte tragende FKV-Strukturen. Über die Schwingfestigkeit der Faser-Kunststoff-Verbunde (FKV) und die Lebensdauerabschätzung dieser Werkstoffklasse auf Basis verschiedener Lastspektren wurden insbesondere von Christoph Kensche verschiedenen Arbeiten durchgeführt und auch auf dem Symposium für Segelflugzeugentwicklung vorgestellt. Hingegen ist die Betriebsfestigkeit von Struktur-Klebungen im Anwendungsbereich der CS22 vergleichsweise wenig untersucht worden.
Über die Jahre wurden in verschiedenen Projekten immer wieder Probleme in Struktur-Klebungen (u.a. Betriebsbelastungsversuche an Versuchs-Holmen) identifiziert, analysiert und spezielle Prüfverfahren weiter entwickelt (Projekt „Tragflügel neuer Technologie für die allgemeine Luftfahrt“, FK SIF765). Im Rahmen des LuFo-Vorhabens GeAviBoo (General Aviation Booster) wurde in zwei Arbeitspaketen das Thema erneut aufgegriffen und Betriebsbelastungsversuche an Klebproben durchgeführt. Im Rahmen des Vortrages werden die Erkenntnisse der letzten 10 Jahre aufbereitet und die neusten Ergebnisse vorgestellt.
T2 - Symposium für Segelflugzeugentwicklung
CY - Online meeting
DA - 19.11.2020
KW - Polymer Matrix Composites
KW - Betriebsfestigkeit
KW - Klebung
KW - General Aviation
PY - 2020
AN - OPUS4-51861
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
T1 - Funktionalisierung von Fasern für zementgebundene Materialien - ausgewählte Prüfmethoden
N2 - Die geringe Zugfestigkeit von zementgebundenen Materialien kann durch die Zugabe von Fasern maßgeblich verbessert werden. Ziel eines gemeinsamen Verbundprojekts mit einem Industriepartner war die Erhöhung der Leistungsfähigkeit von kurzen Polymer- und Carbonfasern durch eine Verbesserung des Verbundes zwischen Faseroberfläche und Zementsteinmatrix.
Von der IONYS AG wurde dazu eine spezielle Funktionalisierung entwickelt, die über eine Hydrophilisierung der Faseroberfläche eine chemische Anbindung an die Zementsteinmatrix gewährleistet. Aufgabe der BAM war es, die Effizienz der neuen Beschichtung bezüglich der Erhöhung der Nachrissbiegezugfestigkeit und der Reduzierung der Schwindrissbildung während der Erhärtungsphase zu quantifizieren. Die Ergebnisse zeigen, dass die Funktionalisierung die Neigung zur Schwindrissbildung für die Carbonfasern und in noch stärkerem Maße für die Polymerfasern reduziert.
Eine Erhöhung der Nachrissbiegezugfestigkeit konnte dagegen nur für die deutlich steiferen Carbonfasern nachgewiesen werden.
T2 - 10. Kolloquium Industrieböden
CY - Esslingen, Germany
DA - 03.03.2020
KW - Fibres
KW - Cementitious materials
KW - Shrinkage
KW - Strain hardening
PY - 2020
AN - OPUS4-51914
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotula, Stefan
T1 - Messsystemanalyse („Ringversuch“) zu WIPANO-Vorhaben „GELELEK“ – Zusammenfassung der Ergebnisse
N2 - Im Rahmen des WIPANO-Vorhabens „GELELEK“ wurde ein Ringversuch durchgeführt, bei dem ca. 20 Teilnehmer aus Wirtschaft und Forschung teilnahmen. Dabei wurde eine neuartige elektrochemische Messung von Zinkoberflächen durchgeführt, welche an der BAM entwickelt und für industrielle Anwendung optimiert wurde. Dabei diente ein an der BAM geschriebener Normvorschlag als Anleitung. In dem Vortrag werden die Ergebnisse und Auswertungen der Messdaten vorgestellt.
T2 - Sitzung der Ad hoc Gruppe "GELELEK" im DIN-Normenausschuss Materialprüfung (NMP)
CY - Online Meeting
DA - 07.09.2021
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosionsuntersuchungen
KW - Ringversuch
KW - Normung
KW - Zink
PY - 2021
AN - OPUS4-53280
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tache, O.
T1 - Synthesis of SiO2 Nanoparticles as reference materials: Metrological measurements and in-situ kinetics in lab with Small Angle X-Ray Scattering
N2 - The unambiguous correlation of possible health and sustainability risks to nanoparticle size must be enabled by reliable measurement of nanoparticle size, to ensure comparability and compatibility between results measured under different methods. The NPSIZE project funded by European Metrology Program (EMPIR) develop methods, reference materials and modelling to improve the traceability chain, comparability and compatibility of nanoparticle size measurements. In this work, we present how spherical silica nanoparticles are synthetized with controlled monomodal or bimodal dispersion to be use as reference materials and international round-robin. Improving the fabrication requires a fine understanding of synthesis (1), coupled with an expertise of in-situ or ex-situ analysis methods. This is a new challenge for the analysis : determining not only average characteristics (size, chemical composition and shape ...) but also the concentration and the distribution over the population studied (2). Small-Angle X-ray Scattering (3) allows very precise measurements of the nanoparticles size and concentration that can be directly link to the metric system (4) (metrological traceability) . We developed a SAXS laboratory instrument dedicated to the in-situ characterization of nanoparticles, which enable fast measurements, and the monitoring of the synthesis parameters. Measurement protocols and software processing chain (5) (i.e. size distribution) are also combined & optimized.
T2 - CNANO2021
CY - Toulouse, France
DA - 25.11.2021
KW - X-ray scattering
KW - Silica particles
KW - Synthesis
KW - Reference materials
PY - 2021
DO - https://doi.org/10.5281/zenodo.5749256
AN - OPUS4-53931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Vorstellung des WIPANOVerbundforschungsvorhabens GELELEK: Forschungsziele und Ergebnisse
N2 - Der Vortrag stellt das WIPANOForschungsvorhaben GELELEK vor und fasst die wichtigsten erzielten Ergebnisse zusammen.
T2 - 13. Sitzung des GfKORR Arbeitskreises „Korrosionsuntersuchung und -überwachung“
CY - Online meeting
DA - 08.12.2021
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosionsuntersuchungen
KW - Normung
KW - Ringversuch
KW - Zink
KW - WIPANO
PY - 2021
AN - OPUS4-53946
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Praktische Erfahrungen zur Granulometrie von Pulvern im Submikron- und Nanobereich
N2 - Der Vortrag beleuchtet insbesondere die Herausforderungen die sich bei der Dispergierung der Nanopulver aufgrund der hohen Adhäsivkräfte ergeben. Die Bewertung der Probenpräparation ist nur indirekt zugänglich, aber essentiell für die Zuverlässigkeit der Messergebnisse. Anhand von Beispielen werden Lösungsvorschläge aufgezeigt. Der Vortrag schließt mit einem Vorschlag zur Strategie der Herangehensweise bei der Partikelgrößenbestimmung von Nanopulvern.
T2 - Sitzung des Fachausschusses "Material- und Prozessdiagnostik" der Deutschen Keramischen Gesellschaft: Zuverlässige granulometrische Charakterisierung von Mikro- und Nanopulvern – Voraussetzung für optimierte Keramikwerkstoffe in der Energietechnik
CY - Online meeting
DA - 19.11.2020
KW - Nano-powder
KW - particle size determination
KW - dispersion
KW - sample preparation
PY - 2020
AN - OPUS4-51665
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hofmann, Detlef
T1 - Strukturüberwachung mit lokaler und verteilter faseroptischer Sensorik
N2 - Der Vortrag gibt einen Überblick über die Einsatzmöglichkeiten faseroptischer Sensorik (FOS) als ZfP-Verfahren. Dabei werden an Beispielen lokale und verteilte faseroptische Verfahren zur Dehnungs-, Temperatur- und Risserfassung sowie zur akustischen Messung vorgestellt. Weiterhin werden Möglichkeiten zur Selbstdiagnose von FOS aufgezeigt.
T2 - InnoTesting2020 "Innovative Ideen - neue Testmethoden"
CY - Wildau, Germany
DA - 27.02.2020
KW - Faseroptische Sensorik
KW - Strukturüberwachung
KW - Lichtwellenleiter
KW - Zerstörungsfreie Prüfung
KW - Selbstdiagnose
PY - 2020
AN - OPUS4-51688
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haapalehto, Matias
A1 - Pinomaa, Tatu
A1 - Wang, Lei
A1 - Laukkanen, Anssi
T1 - An atomistic simulation study of rapid solidification kinetics and crystal defects in dilute Al–Cu alloys
N2 - Rapid solidification kinetics of dilute Al–Cu alloys is simulated using a quantum mechanics based bondorder potential (BOP), in free solidification conditions, to determine kinetic and thermodynamic properties of solidification, as well as point defects and chemical ordering of the solidified structures. We measure the anisotropic kinetic coefficient, anisotropic solid–liquid interface energy, as well as solute trapping kinetics in terms of partition coefficient versus velocity and solute drag coefficient. Furthermore, solid–liquid interface free energy and its anisotropy are measured in equilibrium simulations, showing reasonably good agreement with previous studies. We also verified the self-consistency of the MD simulations, by comparing the interfacial temperature vs. velocity to that predicted by the continuous growth model. These solid–liquid interface properties are important for quantitative parametrization of larger scale solidification modeling techniques such as phase field models. We also investigated the point defect content, local chemical ordering, and local crystalline structures in the rapidly solidified samples. We found clustering of solute with vacancies, whereas copper atoms repelled each other in these dilute alloy simulations. In addition to vacancies, a large number of interstitials were found. In solidification velocities approaching the complete solute trapping regime, we found that the vacancies and interstitials formed in conjunction, i.e. as Frenkel pairs. Finally, in addition to FCC, we detected BCC and HCP phases, where the latter two were accompanied by an increase in local copper content. Understanding the formation of point defects and their relationship to chemical ordering is an important step towards controlling the formation of pre-precipitates and precipitates, which are an important strengthening mechanism for aluminum–copper alloys.
KW - Rapid solidification
KW - Aluminum–copper
KW - MD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628722
DO - https://doi.org/10.1016/j.commatsci.2022.111356
SN - 0927-0256
VL - 209
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kumar, Sumit
A1 - Swaminathan, Srinivasan
A1 - Hesse, Rene
A1 - Goldbeck, Hennig
A1 - Ding, Wenjin
A1 - Bonk, Alexander
A1 - Bauer, Thomas
T1 - Understanding the effect of oxide ions on Solar Salt chemistry and corrosion mechanism of 316L stainless steel at 600 °C
N2 - Solar Salt (60 wt% NaNO3, 40 wt% KNO3), used in Concentrated Solar Power (CSP) Thermal Energy Storage (TES) technology, can decompose into various products at elevated temperatures, with oxide ions being one of the known corrosive byproducts. The study mimics Solar Salt aging by intentionally adding sodium peroxide (Na2O2) and sodium oxide (Na2O) at concentrations of 0.005–0.33 wt% to investigate their role in the corrosion of austenitic stainless steel at 600 °C in typical operating conditions. Salt chemistry (nitrite, nitrate, oxide ions, and metal cations) was analyzed every 24 h, and steel corrosion after 168 h was assessed by weight change, corrosion rate, phase analysis, and cross-sectional morphology. Results reveal that at or above 0.135 wt% added Na2O2/Na2O leads to a quasi-steady-state equilibrium of oxide ions in the salt. Interestingly, at these concentrations, the presence of steel further decreases oxide ion concentration. Furthermore, above 0.135 wt%, the corrosion rate increases significantly, along with increased spallation, porosity and disintegration of the corrosion layer, forming a non-protective layer. This study highlights the critical role of oxide ions in the corrosion process.
KW - Solar Salt
KW - High temperature corrosion
KW - Thermal Energy Storage
KW - Alkali oxides
KW - Austenitic stainless steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628463
DO - https://doi.org/10.1016/j.corsci.2025.112849
SN - 1879-0496
VL - 249
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-62846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced periodic surface structures: When electromagnetics drives hydrodynamics
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any material upon irradiation of solids with intense laser radiation. Nowadays processing rates of up to m^2/min are enabling new industrial applications in medicine, optics, tribology, biology, etc. Depending on the specific type of LIPSS, their structural sizes typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, however, a vivid, controversial, and long-lasting debate has emerged during the last two decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter reorganization processes (distinctly after the laser irradiation). This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches.
T2 - 28th International Conference on Advanced Laser Technologies (ALT'21)
CY - Online meeting
DA - 06.09.2021
KW - Laser-induced periodic surface structures, LIPSS
KW - Electromagnetic scattering
KW - Matter reorganization
PY - 2021
DO - https://doi.org/10.24412/cl-35039-2021-21-25-25
AN - OPUS4-53218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - New findings on the formation of corrosion product layers on zinc in the atmosphere
N2 - The presentation shows systematic investigations to describe the corrosion and corrosion product formation processes of pure zinc under the climatic conditions currently prevailing in the Federal Republic of Germany. The investigations in their entirety aim at questioning current and establishing new ways of looking at the formation of corrosion products of pure zinc under atmospheric corrosion conditions. Thus, they make a significant contribution in understanding corrosion protection by zinc and zinc coatings. In particular, the focus is placed on the initial stage of the corrosion product formation. A systematic investigation of this time range, which is characterized by very reactive corrosion products, is only made possible by using gel-type electrolytes. The short periods of time at the beginning of weathering is now measurable and their influence on the formation of corrosion products and the kinetics of layer formation describable. By combining the new electrochemical approach with gravimetric, microscopic and analytical methods, new insights could be gained both on a methodic and scientific level.
T2 - EUROCORR 2021
CY - Online meeting
DA - 20.09.2021
KW - Atmospheric Corrosion
KW - Corrosion
KW - Corrosion products
KW - Gel-type electrolytes
KW - Zinc
PY - 2021
AN - OPUS4-53332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Scattering is a powerful tool to follow nucleation and growth of minerals from solutions
N2 - In recent years, we have come to appreciate the astounding intricacy of the formation process of minerals from ions in aqueous solutions. The original ‘textbook’ image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species [e.g. 1], including solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc. In general, these precursor or intermediate species constitute different, often short-lived, points along the pathway from dissolved ions to the final solids (typically crystals in this context). In this regard synchrotron-based scattering (SAXS/WAXS/HEXD) appears to be the perfect tool to follow in situ and in a time-resolved manner the crystallization pathways because of the temporal and spatial length scales that can be directly accessed with these techniques.
Here, we show how we used scattering to probe the crystallization mechanisms of calcium sulfate. CaSO4 minerals (i.e. gypsum, anhydrite and bassanite) are widespread in natural and industrial environments. During the last several years, a number of studies have revealed indeed that nucleation in the CaSO4-H2O system is non-classical. Our SAXS data demonstrate that gypsum precipitation, involves formation and aggregation of sub-3 nm primary species. These species constitute building blocks of an amorphous precursor phase [2]. Further, we show how in situ high-energy X-ray diffraction experiments and molecular dynamics (MD) simulations can be combined to derive the atomic structure of the primary CaSO4 clusters seen at small-angles [3]. We fitted several plausible structures to the derived pair distribution functions and explored their dynamic properties using unbiased MD simulations based on polarizable force fields. Finally, based on combined SAXS/WAXS, broad-q-range measurements, we show that the process of formation of bassanite, a less hydrated form of CaSO4, is very similar to the formation of gypsum: it also involves the aggregation of small primary species into larger disordered aggregates [4].
Based on these recent insights we formulated a tentative general model for calcium sulfate precipitation from solution. This model involves primary species that are formed through the assembly of multiple Ca2+ and SO42- ions into nanoclusters. These nanoclusters assemble into poorly ordered (i.e. amorphous) hydrated aggregates, which in turn undergo ordering into coherent crystalline units of either gypsum or bassanite (and possibly anhydrite). Determination of the structure and (meta)stability of the primary species is important from both a fundamental, e.g. establishing a general non-classical nucleation model, and applied perspective; e.g. allow for an improved design of additives for greater control of the nucleation pathway.
T2 - Annual Meeting of German Crystallographic Society (29. Jahrestagung der Deutschen Gesellschaft für Kristallographie - DGK
CY - Online meeting
DA - 15.03.2021
KW - Scattering
KW - Calcium sulfate
KW - SAXS/WAXS
PY - 2021
AN - OPUS4-53619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Experimentelle Charakterisierung der WIG-Schweißeignung einer Hoch- und Mediumentropie-Legierung
N2 - Equiatomic multi-element systems with defined entropy are a relatively new mate-rial concept for alloy production. These alloys consist of at least five elements in equiatomic distribution in the case of high entropy alloys (HEA) and three to four elements in equiatomic distribution in the case of medium entropy alloys (MEA). Previous studies on these alloys have focused primarily on their production, micro-structure and the resulting material properties. Meanwhile, the focus here is on the processing of the alloys and their influence on future applications. Up to now, there has been insufficient knowledge of the materials and processes involved in weld-ing.
In this work, therefore, the weldability of a CoCrFeMnNi-HEA and a CoCrNi-MEA by means of a TIG welding process was investigated as a basic system. To this end, the welding parameters were first determined on a reference alloy (Ni-based: 2.4858) and transferred to the welding of the CoCrFeMnNi-HEA and CoCrNi-MEA. Weldability was assessed by testing the absence of defects and microstructures obtained. The weld metal exhibited the dendritic microstructure typical of TIG, with microsegregations forming as interdendritic phases. Increased hardness was de-tected in the weld metal compared to the base metal. In the heat-affected zone, there was little grain growth and, in both alloys, the formation of hot cracks after welding. The cause of the cracks was to be found in the specimen preparation, which had an influence on the subsequent processing. After elimination of this in-fluence, no welding process-related imperfections were found in the CoCrFeMnNi-HEA and CoCrNi-MEA.
In summary, both materials show good fusion weldability by TIG welding. The re-sults of this work thus contribute to the understanding of the weldability of HEA and in particular for CoCrNi-MEA, which was considered in this depth for the first time.
T2 - Verteidigung Masterarbeit Otto von Guericke Universität Magdeburg
CY - Magdeburg, Germany
DA - 20.10.2021
KW - Hochentropielegierung
KW - Mediumentropielegierung
KW - WIG-Schweißen
PY - 2021
AN - OPUS4-53643
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - In-situ monitoring by thermography: Influence of the scan angle on the melt pool
N2 - Online quality control of security relevant parts manufactured by Laser Powder Bed Fusion (LPBF) remains to be a challenge due to the highly complex process conditions. Furthermore, the influence of characteristic scan strategy parameters is not sufficiently clarified yet due to the commonly used method of single-track investigations. In this contribution, this topic is addressed by observing large 316L volume sections using in-situ melt pool monitoring by thermography in high temporal and spatial resolution. In detail, the influence of the scan angle on the melt pool geometry is investigated on. Characteristic melt pool features are extracted from the image data and analyzed using statistical methods data for altering scan angles. The results show significant changes in the melt pool dimensions and temperature distribution over the scan angle rotation. A first explanation approach is presented that connects the observed changes to phenomena of beam attenuation by metal vapor plume.
T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online meeting
DA - 12.10.2020
KW - Laser Powder Bed Fusion
KW - Thermography
KW - In-situ Monitoring
KW - Angle dependency
PY - 2020
AN - OPUS4-51953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Neue Erkenntnisse zur Deckschichtbildung von Zink an der Atmosphäre
N2 - Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
T2 - Sitzung des Forschungsbeirats des Gemeinschaftsausschuss Verzinken e.V.
CY - Online Meeting
DA - 07.10.2021
KW - Atmosphärische Korrosion
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Zink
PY - 2021
AN - OPUS4-53478
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Vorstellung des WIPANO-Vorhabens GELELEK
N2 - Der Vortrag stellt das WIPANO-Forschungsvorhaben GELELEK vor und fasst die wichtigsten erzielten Ergebnisse zusammen.
T2 - Sitzung des Forschungsbeirats des Gemeinschaftsausschuss Verzinken e.V.
CY - Online meeting
DA - 07.10.2021
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosionsuntersuchungen
KW - Normung
KW - Ringversuch
KW - Zink
PY - 2021
AN - OPUS4-53479
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Wie gehe ich bei einer Schadensuntersuchung vor?
N2 - Die Vorgehensweise bei einer Schadensanalyse wird beschrieben. Hinweise zu Methodik, Fehlervermeidung und Verhalten werden gegeben.
T2 - Der sichere Einsatz von Werkstoffen aus Kupfer und Kupferlegierungen in der Trinkwasserinstallation
CY - Online meeting
DA - 12.20.2021
KW - Schadensanalyse
KW - Korrosion
PY - 2021
AN - OPUS4-53518
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simon, Franz-Georg
T1 - EI-GEO (S&T CALL 2017), Environmental impact of geosynthetics in aquatic systems
N2 - 2021 marks the 10th anniversary of the first ERA.Net RUS joint call for European-Russian STI cooperation projects. Pooling the resources of more than 20 European and Russian funding agencies, more than 150 projects were funded with an estimated budget of about € 60 million.
Being even larger than many thematic ERA.NETs, the ERA.Net RUS Plus has been the biggest and most successful regional ERA.NET so far. Indicating a strong demand for scientific cooperation, the smaller-scale projects funded within the ERA.Net RUS (Plus) calls perfectly complement Russian participation in the EU Framework Programmes.
Not least of all, the ERA-Net RUS calls are examples of successful collaboration at a time when cooperation in other fields is complicated by the politically challenging situation. These calls contributed to keeping the communication channels open.
Against this background a dedicated event in late 2021 highlighted what has been achieved within the first decade of the initiative. The project EI-GEO coordinated by BAM was selected as best practice project. The presentation displays the main results of the project and discusses the key success factors.
T2 - ERA.Net RUS: Celebrating ten years of multilateral European-Russian Research and Innovation cooperation
CY - Online meeting
DA - 09.12.2021
KW - Geosynthetics
KW - Coastal protection
KW - European research area
PY - 2021
AN - OPUS4-53965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Nanomaterial characterisation - The long way to standardisation
N2 - In 1981 the OECD published the Test Guideline on Particle size and size distribution. This TG is still a valid document for the measurement of particles all over the world.
When nanomaterials gained importance, ISO set up a technical commitee for Nanotechnologies in 2005 and the OECD followed this step in 2006 with the Working Party on Manufactured Nanomaterials.
In the following years ISO and OECD published several documents about nanomaterials and the systematisation developed.
In 2017 it was finally clear that nanomaterials need to be adressed in another way than chemicals and in 2020 ECHA revised the REACH-Annexes accordingly and included nanomaterials.
Unfortunately there is a little problem with this: Only a few applicable test guidelines exit for the measurement of the nanomaterials. Several test guidelines date from 1981 and do not address nanomaterials.
The logical next step for the OECD would be to publish a series of test guidelines which are indeed currently prepared and will be shown in this talk.
Finally there is an additional need for the future of NM standardisation: Digitalisation.
T2 - Bilateral workshop with Uni Bermingham
CY - Online meeting
DA - 10.03.2021
KW - Nano
KW - Standardisation
KW - Test guideline
KW - OECD
KW - Nanomaterial
PY - 2021
AN - OPUS4-53822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Le, Quynh Hoa
T1 - Licht- und Elektronenoptische 3D-Verfahren zur Analyse von Bruchflächen
N2 - Die Analyse von Bruchflächen wird in der Schadensanalyse meist auf der Basis von Erfahrungswissen vorgenommen, welches aus vorliegenden Untersuchungen, eigenen Vergleichsversuchen und aus der Literatur stammt. Durch Vergleiche mit bereits vorliegenden Bildern werden qualitativ Bruchmechanismen ermittelt. Grundlage sind zumeist zweidimensionale Bilder aus licht- und elekt-ronenoptischen Verfahren. Quantitative Aussagen beziehen sich bislang beispielsweise auf makroskopische Anteile von Bruchmechanismen oder die Ausmessung von Schwingstreifen. In jüngerer Zeit gibt es vermehrt Ansätze, Computer-Algorithmen einzusetzen, die in der Lage sind, unterschiedlich strukturierte Bruchmerkmale zu finden und zu klassifizieren. Im hier vorgestellten IGF-Vorhaben „iFrakto“, IGF Vorhaben Nr.: 21477 N, werden licht- und elektronenoptisch Topographie-Bilder erzeugt und die gewonnenen 3D-Informationen zusammen mit den klassischen 2D-Bildern ausgewertet.
T2 - Treffen der AG Fraktographie im Gemeinschaftsausschuss Rasterelektronenmikroskopie in der Materialprüfung
CY - Online meeting
DA - 19.11.2021
KW - 3D REM
KW - Fraktographie
KW - Bruchflächen
PY - 2021
UR - https://dgm.inventum.de/widget/preview/45d8c33d-622b-43e2-8459-ba783394a723/611d133ebdac0611d133ebdac1
AN - OPUS4-53800
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Size matters! - Auf dem Weg zu einer neuen OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien
N2 - Vorstellung der Ergebnisse bei der Entwicklung einer neuen OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien.
Ergebnisse:
Ideal sphärische Partikel sind gut und verlässlich mit vielen Methoden charakterisierbar.
Reale (Nicht ideale) Materialien sind gut charakterisierbar, wenn eine gewisse Homogenität und Stabilität vorliegt.
Stark inhomogene und stark agglomerierende Partikel liefern deutlich unterschiedliche Ergebnisse für verschiedene Methoden.
Partikel mit geringen Größenunterschieden lassen sich mit allen Methoden gut charakterisieren.
Partikel mit sehr deutlichen Größenunterschieden führen häufig zu einer Unterbewertung der kleineren Partikel.
Vollautomatische Partikeldetektion bei elektronenmikroskopischen Aufnahmen ist z.Zt. noch stark fehleranfällig und kann daher nicht empfohlen werden.
Es hat sich gezeigt, dass alle Methoden zur Bestimmung der Partikelgrößenverteilung Vor- und Nachteile haben. Es ist dringend zu empfehlen Größenverteilungen immer mit mindestens zwei unterschiedlichen Methoden zu bestimmen: Bildgebend und mit gute Anzahlstatistik.
Verschiedene Durchmesser wurden in der TG-PSD mit einem Indexsystem versehen, welches zukünftig Verwechslungen zwischen unterschiedlichen Durchmessern vermeiden soll.
Wird ein bestimmter Durchmesser benötigt (z.B. hydrodynamisch, aerodynamisch), muss die Methode passend gewählt werden. Eine Umrechnung von einem Durchmesser in einen anderen ist in der Regel fehlerbehaftet.
Es wurde ein einheitliches Reporting-System in der TG-PSD eingeführt.
T2 - Fachseminar des Umweltbundesamtes
CY - Online meeting
DA - 14.04.2021
KW - Nano
KW - OECD
KW - Prüfrichtlinie
KW - Nanomaterial
KW - BMU
PY - 2021
AN - OPUS4-53823
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien
N2 - Abschlusspräsentation des Projektes "OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien" - Projektteil Nanopartikel.
Es hat sich gezeigt, dass alle Methoden zur Bestimmung der Partikelgrößenverteilung Vor- und Nachteile haben. Es wird dringend empfohlen Größenverteilungen immer mit mindestens zwei unterschiedlichen Methoden zu bestimmen: Bildgebend und mit gute Anzahlstatistik.
Verschiedene Durchmesser wurden in der TG-PSD mit einem Indexsystem versehen, welches zukünftig Verwechslungen zwischen unterschiedlichen Durchmessern vermeiden soll.
Wird ein bestimmter Durchmesser benötigt (z.B. hydrodynamisch, aerodynamisch), muss die Methode passend gewählt werden. Eine Umrechnung von einem Durchmesser in einen anderen ist in der Regel fehlerbehaftet.
Es wurde ein einheitliches Reporting-System in der TG-PSD eingeführt.
T2 - Fachgespräch zur OECD - TG PSD - BMU BMWi BAM BAuA UBA
CY - Online meeting
DA - 10.09.2021
KW - Nano
KW - OECD
KW - Nanopartikel
KW - Prürfrichtlinie
KW - Nanomaterial
PY - 2021
AN - OPUS4-53825
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Neue Erkenntnisse zur Deckschichtbildung von Zink an der Atmosphäre
N2 - Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
T2 - Sitzung des GfKORR Arbeitskreises „Korrosion und Korrosionsschutz von Eisen und Stahl“
CY - Online meeting
DA - 22.06.2021
KW - Atmosphärische Korrosion
KW - Gelartige Elektrolyte
KW - Deckschichtbildung
KW - Zink
PY - 2021
AN - OPUS4-52843
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Florian, Camilo
T1 - Femtosecond laser-induced oxidation in the formation of periodic surface structures
N2 - Laser-induced oxide graded layers may contribute to the formation of a new type of embedded low-spatial frequency LIPSS with an anomalous orientation parallel to the laser polarization. In this contribution, we explore this effect experimentally with femtosecond laser pulses and numerically by finite-difference time-domain (FDTD) calculations.
T2 - 2021 Conference on Lasers and Electro-Optics/Europe – European Quantum Electronics Virtual Conferences
CY - Online meeting
DA - 21.06.2021
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface oxidation
KW - Femtosecond laser ablation
KW - Finite-difference time-domain calculations
PY - 2021
AN - OPUS4-52859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stephan-Scherb, Christiane
T1 - Novel insights into high temperature corrosion phenomena by advanced X-ray methods
N2 - A variety of materials of technological interest change their properties through contact with reactive media. Solid-gas reactions lead to a variety of reaction products on the surfaces and internal interfaces. The observation of nucleation and growth processes in the environment where they occur (in situ) from a chemical-structural perspective is especially challenging for aggressive atmospheres. The talk presents innovative approaches to study corrosion mechanisms using advanced X-ray methods. Using energy dispersive X-ray diffraction and X-ray absorption spectroscopy in different tailor made environmental reaction chambers, valuable insights into high temperature oxidation and sulfidation processes were gained. Fe-based alloys were exposed to hot and reactive atmospheres containing gases like SO2, H2O and O2 at 650°C. During the gas exposure the tailor made reaction chambers were connected to a high energy diffraction end station at the synchrotron. The crystallization and growth of oxide and sulfide reaction products at the alloy surfaces were monitored by collecting full diffraction pattern every minute. Careful examination of shape and intensity of phase-specific reflections enabled to a detailed view on growth kinetics. These studies showed, oxides are the first phases occurring immediately after experimental start. As soon as reactive gas media enter the chamber, the conditions change and different reaction products, such as sulfides start to grow. A comparison of different gas environments applied, illustrated the differences in the type of reaction products. The in situ observation of high temperature material degradation by corrosion made it possible to study the contribution of phases, which are not stable at room temperature. For instance, wuestite (Fe1-xO), was frequently observed at high temperatures in humid gases on Fe with 2 wt.% and 9 wt.% chromium, but not at room temperature. The strength of the occurrence of this phase additionally explains why, despite a higher Cr content, ferritic alloys with 9 wt.% Cr in a challenging atmosphere prevent the intrinsic formation of protective layers. The in situ observations were supplemented by careful considerations of thermodynamic boundary conditions and detailed post characterization by classical metallographic analysis. Additionally, the structure and chemistry of the dominant oxide layers were evaluated using X-ray absorption near edge structure spectroscopy. The talk will give an overview about chances and challenges for studying high temperature corrosion phenomena by advanced X-ray methods.
T2 - MRS Spring Meeting CT08.02.01
CY - Online Meeting
DA - 18.04.2021
KW - XRD
KW - Spectroscopy
KW - Corrosion
KW - High temperature
KW - In-situ
PY - 2021
AN - OPUS4-52486
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Sample Preparation of Nano-Powders for Particle Size Determination
N2 - The use of increasingly finer starting powders up to nanopowders can also be observed in the field of ceramics. Their advantages consist, for example, in their lower activation energy, an increase in strength or unique optical properties. However, handling and characterization of the powders are much more difficult. The main reason for this is the very high adhesive forces between the particles and between particles and other surfaces, too. Therefore, submicron and even more so nanoparticles tend to agglomerate and their separation into primary particles during sample preparation prior to particle sizing is of particular challenge. A representative measurement sample is only obtained when it no longer contains agglomerates. The evaluation of the dispersion process and a decision on whether it was successful thus increases in importance for the reliability of the measurement results of particle sizing.
The presentation uses examples to show possible approaches and provides information on possible sources of error.
It is shown that successful granulometric characterisation of fine powders requires both an improved dispersion technique and very often an effective combination of two or more measurement methods.
T2 - 96. Jahrestagung der Deutschen Keramischen Gesellschaft
CY - Online Meeting
DA - 19.04.2021
KW - Agglomerates
KW - Nano-powder
KW - Dispersion process
PY - 2021
AN - OPUS4-52503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fiedler, Saskia
T1 - Giant photon bunching of WS2 monolayer in cathodoluminescence
N2 - Cathodoluminescence (CL) spectroscopy has become a powerful tool to study nanostructures due to its high spectral and spatial resolution down to sub-nanometer. More recently, CL technique has also been used for second order auto-correlation measurements (g(2)(t)) to identify different single photon emitters and photon bunching in different materials [1-2].
In this work, tungsten disulfide (WS2) monolayers encapsulated in hexagonal boron nitride (hBN) with and without monocrystalline Au nanodisks (NDs) have been studied, using CL and PL spectroscopy as well as g(2)-CL- and PL-measurements.
CL and PL maps of different WS2 monolayers before/after Au ND deposition show a narrow peak at ~625 nm without any background emission. In CL, the hBN not only protects WS2 from the electron beam but also acts as a charge carrier sink which substantially increases the CL signal [3]. A further CL enhancement is achieved by Au ND deposition, exhibiting the maximum at the center of the NDs without any size dependence. The PL intensity is unaffected. This indicates that Purcell enhancement cannot be the underlying mechanism.
Furthermore, a giant CL-photon bunching of the hBN-encapsulated WS2 monolayers is found which is independent of the applied voltage but highly dependent on the electron beam current. At the lowest current of ~2 pA, a CL bunching factor of up to 160 is observed. Varying thicknesses of the surrounding hBN increases the overall CL signal but does not affect the bunching factor, though it exhibits small local changes within the same flake. In contrast, there is no PL correlation (g(2)(0) = 1).
Interestingly, this photon bunching can be further increased by Au NDs, resulting in the highest ever observed bunching factor of close to 2200. Once again, this enhancement is independent of the Au ND’s diameter although some disks show higher bunching factors than others. Most likely, the Au acts as shield for the incoming primary electrons, resulting in an even further decreased current, and thereby, increased bunching.
In conclusion, large CL-photon bunching is found in hBN-encapsulated WS2 monolayers which can be substantially enhanced by Au NDs.
References
[1] M.A. Feldmann, E.F. Demitrescu, D. Bridges, M.F. Chisholm, R.B. Davidson, P.G. Evans, J.A. Hachtel, A. Hu, R.C. Pooser, R.F. Haglund, B.J. Lawrie, Phys. Rev. B, 97, 081404(R) (2018)
[2] S. Meuret, L.H.G. Tizei, T. Cazimajou, R. Bourrellier, H.C. Chang, F. Treussartm M. Kociak, Phys. Rev. Letter, 114, 197401 (2015)
[3] S. Zheng, J.-K. So, F. Liu, Z. Liu, N. Zheludev, H.J. Fan, Nano Lett., 17, 6475-6480 (2017)
T2 - GSELOP2021
CY - Paris, France
DA - 23.08.2021
KW - Cathodoluminescence
KW - Photon bunching
KW - 2D materials
KW - TMDCs
KW - Au nanodisks
KW - Transition metal dichalcogenide
KW - Au nanoparticles
PY - 2021
AN - OPUS4-53153
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Florian, Camilo
T1 - Silicon surface amorphization and re-crystallization via single femtosecond laser pulses
N2 - Silicon is the material responsible for most of the technological developments during the past century, making it one of the most studied materials along different disciplines. However, there are still unturned stones regarding its superficial re-solidification after femtosecond laser-induced local melting. In this presentation, we report irradiation experiments with single femtosecond pulses (790 nm, 30 fs) with a spatially Gaussian distribution on two different types of silicon with orientations <111> and <100>. The surface modifications were studied in detail via different techniques, including optical microscopy, atomic force microscopy, spectroscopic imaging ellipsometry, energy dispersive X-ray spectroscopy and high-resolution transmission electron microscopy. We quantitatively estimate the resulting radial amorphous layer depth profiles with maximum thicknesses around some tenths of nanometers for fluences in between the melting and ablation thresholds. In particular, spectroscopic imaging ellipsometry (SIE) allowed fast data acquisition using multiple wavelengths to provide experimental measurements for calculating the nanometric radial amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. SIE proved to be capable of detecting and measuring nanometric structural and chemical modifications (oxidation) on the studied laser spots. The accuracy of the SIE-based calculations is verified experimentally by characterizing an in-depth material lamella via high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). For completeness, we present a mathematical modelling for the melt layer thickness considering different optical absorption processes including one photon absorption, two photon absorption and free-carrier absorption, highlighting the relevance of the latter one in the femtosecond laser-induced melting of silicon.
T2 - 28th International Conference on Advanced Laser Technologies (ALT'21)
CY - Online meeting
DA - 06.09.2021
KW - Silicon
KW - Femtosecond laser
KW - Phase transitions
KW - Spectroscopic imaging ellipsometry
KW - Transmission electron microscopy
PY - 2021
AN - OPUS4-53235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fiedler, Saskia
A1 - Ton-That, C.
A1 - Phillips, M. R.
T1 - Defect-free ZnO nanorods with high angular distribution for enhanced excitonic emission
N2 - AbstractLow-temperature hydrothermal growth has emerged as a popular method for the fabrication of ZnO nanorods (NRs), increasing the functionality and utility of ZnO-based devices. In this work, we study the influence of growth time, temperature and seed layer on the dimensions and angular distribution of ZnO NRs. High-quality NRs with a crisscrossed 60° angular distribution have been grown with a 20–60 nm diameter and 600 nm length. We show that, within the ideal range of growth parameters, the growth time and temperature have no controllable influence on NR diameter and length, while the deposition method and size of the pre-growth deposited ZnO seeds affects diameter and NR angular alignment. We demonstrate advantages of using crisscross-aligned NRs over planar ZnO for the enhancement of ZnO excitonic emission by optical coupling with gold nanoparticles. These results can be readily adapted for applications that involve surface coating-mediated enhancement of both light emission and injection.
KW - ZnO nanorod
KW - Hydrothermal growth
KW - Seed layer
KW - Angular distribution
KW - Cathodoluminescence
KW - Luminescence enhancement
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618176
DO - https://doi.org/10.1557/s43578-023-00941-x
SN - 0884-2914
SN - 2044-5326
VL - 38
IS - 8
SP - 2145
EP - 2155
PB - Springer
CY - Berlin
AN - OPUS4-61817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schardt, Annika
A1 - Schmitt, Johannes
A1 - Engelhard, Carsten
T1 - Single particle inductively coupled plasma mass spectrometry with nanosecond time resolution
N2 - In this proof-of-principle study, we present our contribution to single particle inductively coupled plasma mass spectrometry (spICP-MS) developments with a novel in-house built data acquisition system with nanosecond time resolution (nanoDAQ) and a matching data processing approach. The new system can continuously sample the secondary electron multiplier (SEM) detector signal and enables the detection of gold nanoparticles (AuNP) as small as 7.5 nm with the commercial single quadrupole ICP-MS instrument used in this study. Recording of the SEM signal by the nanoDAQ is performed with a dwell time of approximately 4 ns. A tailored method was developed to process this type of transient data, which is based on determining the temporal distance between detector events that is denoted as event gap (EG). We found that the inverse logarithm of EG is proportional to the particle size and that the number of detector events corresponding to a particle signal distribution can be used to calibrate and determine the particle number concentration (PNC) of a nanoparticle dispersion. Due to the high data acquisition frequency, a statistically significant number of data points can be obtained in 60 s or less and the main time limitation for analyses is merely the sample uptake time and rinsing step between analyte solutions. At this stage, the data processing method provides average information on complete data sets only and will be adapted to enable particle-by-particle analysis with future hardware/software revision.
KW - ICP-MS
KW - Nanoparticles
KW - Nanosecond time resolution
KW - Single particle detection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612706
DO - https://doi.org/10.1039/d3ja00373f
SN - 1364-5544
SN - 0267-9477
VL - 39
IS - 2
SP - 389
EP - 400
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-61270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fosodeder, P.
A1 - Baumgartner, W.
A1 - Steinwender, C.
A1 - Hassel, A. W.
A1 - Florian, Camilo
A1 - Bonse, Jörn
A1 - Heitz, J.
T1 - Repellent rings at titanium cylinders against overgrowth by fibroblasts
N2 - The invention of new miniaturized and smart medical implants continues in all medical fields, including miniaturized heart pacemakers. These implants often come with a titanium (Ti) casing, which may have to be removed after several months or years and shall therefore not be completely overgrown by cells or scar tissue after implantation. Scar tissue is mainly formed by fibroblast cells and extracellular matrix proteins like collagen produced by them. Suppression of fibroblast growth at Ti surfaces could be achieved by 800 nm femtosecond laser-ablation creating self-organized sharp spikes with dimensions in the 10 μm-range which are superposed by fine sub-μm parallel ripples. On flat Ti control samples, the best results regarding suppression of cell growth were obtained on spike-structures which were additionally electrochemically anodized under acidic conditions. When Ti cylinders with a diameter of 8 mm (similar as the pacemakers) were placed upright in a culture of murine fibroblasts, a multi-layer cell growth up to a height of at least 1.5 mm occurred within 19–22 days. We have demonstrated that a laser-structured and anodized ring around the Ti cylinder surface is an effective way to create a barrier that murine fibroblasts were not able to overgrow within this time.
KW - Cell-repellent surfaces
KW - Femtosecond laser-processing
KW - Electrochemical treatment
KW - Laser-induced micro- and nanostructures
KW - Medical implants
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509966
DO - https://doi.org/10.1515/aot-2019-0070
SN - 2193-8576
SN - 2193-8584
VL - 9
IS - 3 (Topical issue: Laser micro- and nano-material processing - Part 2)
SP - 113
EP - 120
PB - De Gruyter
CY - Berlin
AN - OPUS4-50996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser-induced Periodic Surface Structures - Mechanisms, Applications, and unsolved Problems
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m^2/min level, industrial applications of LIPSS are sometimes limited by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation reviews the currently existent theories of LIPSS. A focus is laid on the historic development of the fundamental ideas behind the LIPSS, their corresponding mathematical descriptions and numerical implementations, along with a comparison and critical assessment of the different approaches. Moreover, some unsolved scientific problems related to LIPSS are identified and the pending technological limitations are discussed. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.
T2 - SPIG 2022 - 31st Summer School and International Symposium on the Physics of Ionized Gases
CY - Belgrade, Serbia
DA - 05.09.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Femtosecond laser processing
PY - 2022
AN - OPUS4-55813
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 50, Heft 2 & 3
T3 - Amts- und Mitteilungsblatt der BAM - 2/2020 & 3/2020
KW - Anerkennungen
KW - Zulassungen
KW - Gefahrgutregeln
KW - Festlegungen
KW - Richtlinien
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512342
SN - 0340-7551
VL - 50
IS - 2 & 3
SP - 1
EP - 151
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-51234
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hille, Falk
A1 - Sowietzki, D.
A1 - Makris, R.
T1 - Luminescence-based early detection of fatigue cracks
N2 - Classic non-destructive fatigue crack detection methods reveal the state of the fatigue damage evolution at the moment of application, generally not under operational conditions. The here introduced crack luminescence method realizes a clear visibility of the occurred and growing crack in loaded components during operation. Different established experiments show that due to the sensitive coating a crack Formation can be detected even in early stage under the premise the crack reached the surface. The coating consists of two layers with different properties and functions. The bottom layer emits light as fluorescence under UV radiation. The top layer covers the fluorescing one and prevents the emitting of light in case of no damage at the surface. In case of surface crack occurrence, the luminescent light is clearly noticeable by visual observations and also by standard camera equipment which makes automated crack detection possible as well. It is expected that crack luminescence can increase structural safety as well as reduce costs and time for inspections and preventive maintenance.
KW - Coating
KW - Fatigue
KW - Crack damage detection
KW - Luminescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510517
DO - https://doi.org/10.1016/j.matpr.2020.02.338
SN - 2214-7853
SP - 1
EP - 5
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - ELENA: a European project for electrical nanoscale metrology in industry
N2 - A competitive advantage in the semiconductors industry is gained through the exploitation of new materials and processes, translating into improved components’ performances. This requires a metrological infrastructure allowing reliable nanoscale characterisation of new materials and devices, particularly in terms of their electrical parameters and properties. Traceability and reliability of nanoscale measurements stand as a major challenge for electrical properties (i.e. resistance, impedance) using conductive atomic force microscopy (C-AFM) and scanning microwave microscopy (SMM) techniques. The non-destructive analysis nature of these two methods is of paramount importance for the characterization of devices and components. However, the state of the art still lacks established measurement protocols, easy to use reference standards, well-defined best practice guides and easy to use 3D models to assess environmental and external stimulation effects. Moreover, costly instrumentation, particularly for high-frequency measurements, still hinders efficient advancements in these directions.
ELENA is a 3-years European project that aims at bringing solutions to the aforementioned difficulties. To achieve this goal, the project uses a combination of nanoscale electrodynamic scanning probe methods in combination with optical tools such as spectroscopic ellipsometry on several lateral length scales to determine the electrical properties of layers and small structures.
T2 - ICSE-9: The 9th International Conference on Spectroscopic Ellipsometry
CY - Beijing, China
DA - 2022-05-21
KW - Imaging Ellipsometry
KW - Electrical thin layers
KW - Scanning Probe methods
KW - Hybrid metrology
PY - 2022
AN - OPUS4-55464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schardt, Annika
A1 - Schmitt, Johannes
A1 - Engelhard, Carsten
T1 - Cover image for the article "Single particle inductively coupled plasma mass spectrometry with nanosecond time resolution"
N2 - Image for the front cover of the issue 39(2) of the JAAS (Journal of Analytical Atomic Spectrometry). See Annika Schardt et al., pp. 389–400. Image reproduced by permission of Annika Schardt, Johannes Schmitt and Carsten Engelhard.
KW - Analytical chemistry
KW - Nanoparticles
KW - Single-particle characterization
KW - Instrumentation
KW - spICP-MS
PY - 2024
DO - https://doi.org/10.1039/D4JA90005G
SN - 1364-5544
SN - 0267-9477
VL - 39
IS - 2
SP - 295
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-62156
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
A1 - Lehmann, Jens
T1 - Einfach und doch speziell - Das Korrosionsverhalten nichtrostender Stähle
N2 - In diesem zweiten Teil wird das spezielle Korrosionsverhalten nichtrostender Stähle vorgestellt.
T2 - ISER Kursleiterfortbildung 2022
CY - Düsseldorf, Germany
DA - 26.09.2022
KW - Korrosion
KW - Elektrochemie
KW - Experimentalvortrag
PY - 2022
AN - OPUS4-55857
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
A1 - Lehmann, Jens
T1 - Einfach und doch komplex - Korrosion metallener Werkstoffe
N2 - In diesem Teil 1 werden die Grundlagen der Korrosion für metallene Werkstoffe zusammengefasst.
T2 - ISER Kursleiterfortbildung 2022
CY - Düsseldorf, Germany
DA - 26.09.2022
KW - Korrosion
KW - Elektrochemie
KW - Experimentalvortrag
PY - 2022
AN - OPUS4-55855
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witt, Julia
T1 - In situ Atomic Force Microscopy (AFM) studies of corrosion processes on thin film coated AA2024-T3 aluminium alloy surfaces
N2 - The performance of functional coatings relies strongly on the stability of the polymer-metal interface. The increasing utilization of multi-material structures in the automotive and aerospace industry necessitates a fundamental understanding of the processes leading to interface degradation for the development of novel strategies to increase corrosion and delamination resistance.
The aim of this project is to investigate the corrosion processes at the buried interface of thin film coated aluminium alloy AA2024-T3 under corrosive and coupled corrosive-mechanical load. A spin coating procedure was developed to synthesize epoxy-like coatings and their nanofiller loaded composites with controlled thickness by layer-by-layer deposition of poly[(o-cresyl glycidyl ether)-co-formaldehyde] and poly-(ethylenimine) bi-layers. Our results indicate that the incorporation of graphene into the epoxy-based coatings leads to the improvement of mechanical and barrier properties. Furthermore, the functional groups play important roles in the interfacial bonding between polymer matrix and the nanofillers. Atomic force microscopy (AFM) results indicate very homogeneous and dense films with a thickness of ~25 nm per bi-layer and the successful integration of the nanofillers into the composite coatings. Ellipsometry measurements of film thickness verified a proportional film growth with the number of deposited layers.
The degradation and delamination behavior of the coating systems was characterized by means of in situ AFM corrosion experiments. Complementary energy dispersive X-ray spectroscopy (EDX) analysis was used to correlate the corrosion and delamination behavior with the different intermetallic particle chemistries and distributions. The presentation will summarize our results on the effect of coating composition and build-up on the local corrosion processes on thin film covered AA2024-T3 aluminium alloys.
T2 - Eurocorr 2021
CY - Online meeting
DA - 20.09.2021
KW - In situ AFM
KW - Corrosion
KW - Thin epoxy-based films
PY - 2021
AN - OPUS4-54053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulz, Wencke
T1 - High temperature corrosion of high (HEA) and medium (MEA) entropy alloys
N2 - The high-temperature corrosion behavior of the medium-entropy alloy Cr33Co33Ni33 (MEA) and the high-entropy alloy Fe20Cr20Co20Ni20Mn20 (HEA) in a mixed gas atmosphere of 10% H2O-2% O2 -0.5% SO2 + Ar as carrier gas [Vol.%] at 800 °C with duration times of t = 24h, 48h and 96h was investigated. Both alloys have a single-phase fcc microstructure. The oxidation kinetics of the HEA-CrMnFeCoNi roughly followed a linear rate law and a slow oxide growth was observable for the MEA-CrCoNi. The scale thickness of the corrosion layer in the quinary alloy increased with exposure time, while the scale thickness in the ternary alloy remained constant at around 1 µm. The MEA-CrCoNi developed a protective Cr2O3 layer with minor buckled parts. Co,Ni-chromite (Co,Ni)Cr2O4 was detected by XRD in minor amounts. The scale on HEA-CrMnFeCoNi displayed a triplex structure of a thin, continuous, inner Cr2O3 layer, a dense, intermediate Mn3O4 layer, and a thick, outer, porous layer consisting of Mn3O4 and MnSO4. Sulphides were only identified in the matrix of HEA-CrMnFeCoNi. Thermodynamic equilibrium calculations with FactSage (Log(S2) vs. Log(O2), ΔG of reactions) are in good agreement with these observations. The intense diffusion of Cr in the ternary alloy leads to an immediate formation of a protective Cr2O3 layer. The fast diffusion of Mn through the bulk HEA material and through the formed Cr2O3 layer compared to the other alloying elements is considered as the rate-limiting process.
T2 - DMG Sektionstreffen Angewandte Mineralogie und Kristallographie
CY - Online meeting
DA - 25.02.2021
KW - Cr2O3
KW - High-Temperature Corrosion
KW - HEA
KW - MEA
PY - 2021
AN - OPUS4-52164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuhlbusch, T.
T1 - Size matters! - Auf dem Weg zu einer neuen OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien _ Projektteil BAuA
N2 - Vorstellung der Ergebnisse bei der Entwicklung einer neuen OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien. (Projektteil Fasern.)
Ergebnisse:
Abweichungen zwischen SEM and TEM insbesondere bei langen Fasern
Die Anwendung von TEM auf kurze Fasern < 5 µm beschränkt
Für SEM wurde keine signifikante Abhängigkeit der Bestimmung der Faserdurchmesser von der Pixelgröße der Aufnahmen festgestellt
Für TEM wurde eine Abhängigkeit der Bestimmung der Faserdurchmesser von der Pixelgröße festgestellt
Der Einfluss der Bildauswertenden auf die Varianz der Ergebnisse ist klein im Vergleich zu der gesamten Varianz.
Nanofasern können mit TEM und SEM bestimmt werden!
T2 - Fachseminar des Umweltbundesamtes
CY - Online meeting
DA - 14.04.2021
KW - Nano
KW - Nanofasern
KW - OECD
KW - Prüfrichtlinie
KW - Nanomaterial
PY - 2021
AN - OPUS4-53824
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuhlbusch, T.
T1 - OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien - Projektteil Fasern
N2 - Abschlusspräsentation des Projektes "OECD Prüfrichtlinie zur Bestimmung der Partikelgröße und Anzahlgrößenverteilung von Nanomaterialien". (Projektteil Fasern)
T2 - Fachgespräch zur OECD - TG PSD - BMU BMWi BAM BAuA UBA
CY - Online meeting
DA - 10.09.2021
KW - Nano
KW - Nanofasern
KW - OECD
KW - Prüfrichtlinie
KW - Nanomaterial
PY - 2021
AN - OPUS4-53826
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - New findings on the formation of corrosion product layers on zinc in the atmosphere
N2 - The presentation shows systematic investigations to describe the corrosion and corrosion product formation processes of pure zinc under the climatic conditions currently prevailing in the Federal Republic of Germany. The investigations in their entirety aim at questioning current and establishing new ways of looking at the formation of corrosion products of pure zinc under atmospheric corrosion conditions. Thus, they make a significant contribution in understanding corrosion protection by zinc and zinc coatings. In particular, the focus is placed on the initial stage of the corrosion product formation. A systematic investigation of this time range, which is characterized by very reactive corrosion products, is only made possible by using gel-type electrolytes. The short periods of time at the beginning of weathering is now measurable and their influence on the formation of corrosion products and the kinetics of layer formation describable. By combining the new electrochemical approach with gravimetric, microscopic and analytical methods, new insights could be gained both on a methodic and scientific level.
T2 - 2nd Task Group Meeting TC124 WG4-TC 250 SC5 Task Group Corrosion
CY - Online Meeting
DA - 06.05.2021
KW - Zinc
KW - Corrosion products
KW - Gel-type electrolytes
KW - Corrosion
KW - Atmospheric corrosion
PY - 2021
AN - OPUS4-52604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Vorstellung des Forschungsvorhabens GELELEK
N2 - Der Vortrag stellt das Forschungsvorhaben GELELEK im Rahmen der Ad hoc Gruppe "GELELEK" des DIN-Normenausschusses Materialprüfung (NMP) vor.
T2 - Sitzung der Ad hoc Gruppe "GELELEK" im DIN-Normenausschuss Materialprüfung (NMP)
CY - Online Meeting
DA - 21.04.2021
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosionsuntersuchungen
KW - Zink
PY - 2021
AN - OPUS4-52541
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotula, Stefan
T1 - Messsystemanalyse („Ringversuch“) zu WIPANO-Vorhaben „GELELEK“
N2 - Der Vortrag stellt die anstehende Messsystemanalyse im Rahmen der Ad hoc Gruppe "GELELEK" des DIN-Normenausschusses Materialprüfung (NMP) vor und erläutert die notwendigen Schritte zur erfolgreichen Durchführung.
T2 - Sitzung der Ad hoc Gruppe "GELELEK" im DIN-Normenausschuss Materialprüfung (NMP)
CY - Online Meeting
DA - 21.04.2021
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosionsuntersuchungen
KW - Zink
KW - Normung
KW - Messsystemanalyse
PY - 2021
AN - OPUS4-52542
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seher, Julia
T1 - Lightweight Aggregates - Recycling of Construction and Demolition Waste
N2 - A brief introduction into the production of lightweight aggregates from construction and demolition waste and some results of the project HYTEGRA.
T2 - Postdoc Symposium: BAM Focus Area Material
CY - Online meeting
DA - 28.04.2021
KW - Leichte Gesteinskörnung
KW - Rohstoffliches Recycling
KW - Reststoffe
KW - Mauerwerkbruch
KW - Papierasche
KW - Speichermaterial
PY - 2021
AN - OPUS4-52606
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
T1 - Current and future technological advancement in polymer matrix composites enabled through fundamental discoveries
N2 - This presentation is a summary of the work from the past 20 years’ development of PMC-testing at the BAM-FB 5.3 with respect to safety-relevant design of advanced light weight structures in aircraft, wind turbine and automotive applications. The talk begins with wood as an example from nature, and emphasizes that load case, fiber architectural design and the production process and quality have to go hand in hand to generate an advanced light weight structure. Since PMC-relevant basic findings of mankind span across hundreds of years, high-performance composite applications today are based more on long term experiences than on breakthrough inventions of modern days.
In the second part of the talk, future plans and projects of FB-5.3 are presented, specifically addressing H2-safety, circular economy, recycling by design and digitalization of PMC-technologies.
T2 - Abteilungsseminar
CY - Online meeting
DA - 07.09.2021
KW - Polymer Matrix Composites
KW - Thermo mechanical fatigue
PY - 2021
AN - OPUS4-54150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
T1 - Beschreibung des Ermüdungsverhaltens von Endlos-Faserverstärkten-Kunststoff-Verbunden mit Hilfe mikromechanischer Modelle
N2 - Im Rahmen des Vortrags werden die neusten Ergebnisse aus dem Fachbereich 5.3 zur Beschreibung des Ermüdungsverhaltens von FKV mittels Mikromechanischer-Modelle präsentiert. Explizit wird der theoretische Ansatz am Beispiel von GFK unter thermomechanischer Beanspruchung hergeleitet und an Hand von Versuchsergebnissen verifiziert.
T2 - Webkonferenz Composites United, Composite Fatigue
CY - Online meeting
DA - 30.09.2021
KW - Faser-Kunststoff-Verbunde
KW - thermomechanische Beanspruchung
KW - Materialmodell
PY - 2021
AN - OPUS4-54151
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
T1 - Internal sulfate resistance of concrete
N2 - If the amount of sulfate within the mix design for concrete is not balanced, ettringite formation which first controls solidification continues while the concrete is hardening. Ettringite forms by reaction of sulfate contained in the cement or in some admixture with calcium aluminate (C3A) as cement component. The “late primary
ettringite formation” promotes an increase in volume within the hardened concrete leading to cracks. To analyze the effect of substituting part of ordinary Portland cement (OPC) by a treated brown coal fly ash mortar bars were tested according to ASTM C452. This test method was originally developed to extrapolate from the internal to external sulfate attack and is based on the idea that by testing a concrete mixture containing sulfate the process of deterioration is accelerated because it does not have to diffuse into the concrete before reaction first. In addition to the samples prescribed in ASTM C452 further samples in the size of the German SVA procedure were tested also designed for accessing the external sulfate resistance. The results show that while the replacement of 25 % of cement by brown coal fly ash leads to length changes around the limit defined by ASTM, the substitution of 50 % cement exceeded the limit by a multiple. The progress of expansion is the very similar for the two geometries tested. In-situ XRD measurements confirmed that while for pastes made of OPC the formation of ettringite is completed after 20 hours, this is not true for the mixtures containing the brown coal fly ash.
In a different study the effect of hydrothermal treatment on the phase composition of ultra-high-performance concrete was analyzed. The results show that the sulfate and aluminate resulting from the decomposition of ettringite are bound into new phases. If this binding is permanent this might allow the larger use of sulfate bearing raw
materials.
T2 - EuroCoalAsh 2021 Conference
CY - Online meeting
DA - 02.11.2021
KW - Brown coal fly ash
KW - Ettringite
KW - Internal sulfate resistance
KW - Test methods
KW - In-situ XRD
KW - Hydrothermal treatment
PY - 2021
AN - OPUS4-54134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Florian, Camilo
T1 - Influence of oxidation in the formation and performance of laser-induced periodic surface structures
N2 - The fabrication of laser-induced periodic surface structures (LIPSS) has been reported for metallic, semiconductor and dielectric materials when irradiated with linearly polarized ultrashort laser pulses. Different sets of processing parameters have been identified and extensively studied, allowing the use of LIPSS for applications in medicine, tribology and surface wetting to name a few. One important parameter that is often not considered is the laser-induced oxidation that is produced especially when oxidation prone materials are irradiated in air environment. This surface oxidation can potentially influence the final structures
size, shape and orientation and modify their functionality in some specific applications.
In this work, we first study the influence of the laser-induced oxidation layer on the formation of LIPSS by characterizing the response of the oxidation prone
hard-coating material chromium nitride. Moreover, we employ complementary surface and depth-profiling analytic techniques to reveal morphological, chemical and structural features of different types of surface structures and LIPSS produced on titanium-based substrates. Finite-difference time-domain (FDTD) calculations finally explain how this superficial oxidation layer promotes the formation of a new type of low spatial frequency LIPSS. Also, we measure the depth-extent of the different oxides formed and demonstrate its beneficial influence for friction reduction and wear resistance applications.
T2 - SPIE Photonics West Conference, Symposium "Laser-Based Micro- and Nano-Processing XVI"
CY - San Francisco, CA, USA
DA - 22.01.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Oxidation
KW - Femtosecond laser
KW - Laser processing
KW - Finite-difference time-domain calculations (FDTD)
PY - 2022
AN - OPUS4-54322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Esmann, M.
A1 - Chimeh, A.
A1 - Korte, A.
A1 - Zhong, J.
A1 - Stephan, S.
A1 - Witt, Julia
A1 - Wittstock, G.
A1 - Talebi, N.
A1 - Lienau, C.
T1 - Plasmonic nanofocusing spectral interferometry
N2 - We describe and demonstrate a novel experimental approach to measure broadband, amplitude- and phase-resolved scattering spectra of single nanoparticles with 10-nm spatial resolution. Nanofocusing of Surface plasmon polaritons (SPPs) propagating along the shaft of a conical gold taper is used to create a spatially isolated, spectrally broad nanoscale light source at ist very apex. The interference between these incident SPPs and SPPs that are backpropagating from the apex leads to the formation of an inherently phase-stable interferogram, which we detect in the far field by partially scattering SPPs off a small protrusion on the taper shaft. We show that these interferograms allow the reconstruction of both the amplitude and phase of the local optical near fields around individual nanoparticles optically coupled to the taper apex. We extract local light scattering spectra of particles and quantify line broadenings and spectral shifts induced by tip-sample coupling. Our experimental findings are supported by corresponding finite-difference time-domain and coupled dipole simulations and Show that, in the limit of weak tip-sample coupling, the measurements directly probe the projected local density of optical states of the plasmonic system. The combination of a highly stable inline interferometer with the inherent optical background suppression through nanofocusing makes it a promising tool for the locally resolved study of the spectral and temporal optical response of coupled hybrid nanosystems.
KW - Plasmonic nanofocusing
KW - Near-field spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504985
DO - https://doi.org/10.1515/nanoph-2019-0397
VL - 9
IS - 2
SP - 491
EP - 508
PB - De Gruyter
AN - OPUS4-50498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönherr, J. A.
T1 - Robust Determination of Fatigue Crack Propagation Thresholds from Crack Growth Data
N2 - To assess the ability of cracks to grow, a robust determination of the threshold against fatigue crack propagation ∆Kth is of paramount importance. The standards ASTM E647 and ISO 12108 introduce operational definitions of ∆Kth based on the crack propagation rate da/dN. For evaluating ∆Kth, both suggest fitting a linear function to a defined subset of the logarithmic ∆K – da/dN test data, where ∆Kth follows by evaluating the linear function at da/dN = 10-7 mm/cycle and da/dN = 10-8 mm/cycle, respectively.
In general, this kind of fit suffers from a bad representation of the actual curvature of the crack propagation curve. Therefore, we propose a robust method for evaluating ∆Kth using a non-linear function that reduces the artificial conservativeness induced by the evaluation method as well as the susceptibility to scatter in test data and the influence of test data density. The method is calibrated against a large set of S690QL crack growth data obtained from a total of 48 specimens, and validated against a set of S355NL and S960QL data (3 specimens each), obtained as a part the IBESS (integral fracture mechanics determination of the fatigue strength of welds) project.
T2 - ECF23 (European Conference on Fracture 2022)
CY - Madeira, Portugal
DA - 27.06.2022
KW - Fatigue crack propagation threshold
KW - ISO 12108
KW - ASTM E647
KW - Data evaluation methods
KW - Experimental determination
PY - 2022
AN - OPUS4-55252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Knigge, Xenia
T1 - First Experiences with the new HAXPES@BAM
N2 - This talk was part of the inauguration event for the new x-ray photoelectron spectrometer with the possibility to measure HAXPES (hard energy x-ray photoelectron spectroscopy). With HAXPES detailed chemical information can now be gained not only from the first outermost nanometres of the sample surface, but also from deeper regions. In this talk first results and experiences handling the spectrometer are shown.
T2 - Inauguration of the HAXPES@BAM - A new Hard-X-Ray Photoelectron Spectrometer
CY - Online meeting
DA - 25.01.2022
KW - HAXPES
KW - Nano@BAM
KW - Surface Analysis
KW - XPS
PY - 2022
UR - https://www.bam.de/Content/EN/Events/2022/2022-01-25-hapex.html
AN - OPUS4-54434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
T1 - Study of micro- and nanoscale wetting properties of lubricants using AFM force-distance curves
N2 - Atomic force microscopy (AFM) plays an important role as a multifuntional tool in nanotribology.In the present work it was shown that the main features of force-distance curves on different lubricants have been characterized and the underlying phenomena could be explained.
KW - Lubricants
KW - Atomic force microscopy
KW - Force-distance curves
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504631
DO - https://doi.org/10.1007/s11249-020-1275-3
SN - 1573-2711
VL - 68
IS - 1
SP - 1
EP - 12
PB - Springer
CY - Cham
AN - OPUS4-50463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
T1 - Editorial: Special issue "Laser-induced periodic surface nano- and microstructures for tribological applications"
N2 - Laser material processing is an emerging technology that generates surface functionalities on the basis of optical, mechanical, or chemical properties. In the form of laser surface texturing (LST), it has attracted a remarkable amount of research to tailor surface properties towards various tribological applications. The main advantages of this single-step, laser-based technology are the contactless machining, featuring a high flexibility, efficiency, and speed, along with the excellent quality of the processed products. LST can be applied precisely localized to sub-micrometric areas, but, via laser beam scanning, it is also feasible for structuring large surface areas at the square meter size.
This Special Issue focuses on the latest developments concerning the tribological performance of laser-generated periodic surface nano- and microstructures and their applications. This includes the laser-based processing of different surface patterns, such as “self-organized” laser-induced periodic surface structures (LIPSS, ripples), grooves, micro-spikes, hierarchical hybrid nano-/micro-structures, microfeatures generated by direct laser interference patterning (DLIP), or even dimples or other topographic geometries shaped by direct laser modification or ablation. The applications of these periodically nano- and micro-patterned surfaces may improve the lubricated or non-lubricated tribological performance of surfaces in conformal and even non-conformal contact through a reduction of wear, a variation of the coefficient of friction, altered load carrying capacity, etc., resulting in energy saving, improved reliability, increased lifetimes as well as durability, leading in turn to extended maintenance intervals/reduced down-time. This can be beneficial in terms of bearings, gears, engines, seals, cutting tools, or other tribological components. Fundamental aspects addressed may involve the investigation of the relevant physical and chemical effects accompanying the laser-generated nano- and microscale topographies, such as alterations of the material structures, the hardness, superficial oxidation, the role of additives contained in lubricants, surface wettability, micro-hydrodynamic effects, etc.
For this Special Issue we aim to attract both academic and industrial researchers and would like to provide a bridge between research in the fields of tribology and laser material processing in order to foster the current knowledge and present new ideas for future applications and new technologies.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Tribology
KW - Applications
KW - Wear
KW - Friction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505948
DO - https://doi.org/10.3390/lubricants8030034
SN - 2075-4442
VL - 8
IS - 3
SP - 34, 1
EP - 34, 3
PB - MDPI
CY - Basel
AN - OPUS4-50594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Reichelt, Manuel
T1 - Untersuchungen zu ungeschmiertem Schwingungsverschleiß an 100Cr6-Kugeln gegen 100Cr6-Ebenen
N2 - Die vorliegende Doktorarbeit handelt von der Bestimmung und der Untersuchung vom Verschleißvolumen und vom Verschleißkoeffizienten bei ungeschmierten Modellversuchen an 100Cr6-Ebenen und -Kugeln unter Schwingungsbeanspruchung. Die experimentelle Arbeit wurde mittels statistischer Auswertung einer großen Menge von eigenen und früheren Versuchsdaten an fünf Tribometern bei umfangreicher Variation der Beanspruchungsparameter durchgeführt. Ziel war es, die Wiederholbarkeit und Reproduzierbarkeit der experimentellen Ergebnisse zu überprüfen sowie das Archard-Gesetz zu verifizieren. Des Weiteren wurde der Einfluss der Luftfeuchtigkeit auf den Verschleiß untersucht.
KW - Verschleißkoeffizient
KW - 100Cr6-Stahl
KW - Gesetz von Archard
KW - Verschleiß-Map
KW - relative Luftfeuchtigkeit
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522664
DO - https://doi.org/10.14279/depositonce-10423
SP - 1
EP - 118
PB - Technische Universität Berlin
CY - Berlin
AN - OPUS4-52266
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dub, S.
A1 - Haftaoglu, Cetin
A1 - Kindrachuk, Vitaliy
T1 - Estimate of theoretical shear strength of C60 single crystal by nanoindentation
N2 - The onset of plasticity in a single crystal C60 fullerite was investigated by nanoindentation on the (111) crystallographic plane. The transition from elastic to plastic deformation in a contact was observed as pop-in events on loading curves. The respective resolved shear stresses were computed for the octahedral slip systems ⟨011¯¯¯⟩{111}, supposing that their activation resulted in the onset of plasticity. A finite element analysis was applied, which reproduced the elastic loading until the first pop-in, using a realistic geometry of the Berkovich indenter blunt tip. The obtained estimate of the C60 theoretical shear strength was about 1/11 of the shear modulus on {111} planes.
KW - Finite element analysis
KW - Fullerite
KW - Nanoindentation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523208
DO - https://doi.org/10.1007/s10853-021-05991-2
VL - 56
IS - 18
SP - 10905
EP - 10914
PB - Springer Nature
AN - OPUS4-52320
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Wolf, M.
A1 - Kranzmann, Axel
T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary
N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60°C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60°C , brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
KW - Carbon capture and storage
KW - Steel
KW - High alloyed steel
KW - Corrosion
KW - Corrosion fatigue
KW - CCS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523948
DO - https://doi.org/10.3390/pr9040594
VL - 9
IS - 4
SP - 594
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement by Monte-Carlo based particle scattering Simulations
N2 - Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined.[1] Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented. [2] These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for ongoing experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au.
T2 - #RSCposter 2023
CY - Online meeting
DA - 28.02.2023
KW - AuNP
KW - Beta decay
KW - Brachytherapy
KW - Cancer treatment
KW - Clustered nanoparticles
KW - DNA
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - LEE
KW - Livermore model
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - OH radical
KW - Penelope model
KW - Radiation damage
KW - Radiation therapy
KW - Radiationtherapy
KW - Radiotherapy
KW - Radioactive decay
KW - Radiolysis
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
KW - beta particle
KW - particle scattering
PY - 2023
AN - OPUS4-57060
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfretzschner, Beate
A1 - Schaupp, Thomas
A1 - Hannemann, Andreas
A1 - Schultz, Michael
A1 - Griesche, Axel
T1 - On the Genesis of Artifacts in Neutron Transmission Imaging of Hydrogenous Steel Specimens
N2 - Hydrogen-charged supermartensitic steel samples were used to systematically investigate imaging artifacts in neutron radiography. Cadmium stencils were placed around the samples to shield the scintillator from excessive neutron radiation and to investigate the influence of the backlight effect. The contribution of scattered neutrons to the total detected intensity was investigated by additionally varying the sample-detector distance and applying a functional correlation between distance and intensity. Furthermore, the influence of the surface roughness on the edge effect due to refraction was investigated.
KW - Refraction
KW - Neutron imaging
KW - Hydrogen
KW - Supermartensitic steel
KW - Backlight
KW - Scattering
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506587
DO - https://doi.org/10.3390/jimaging6040022
VL - 6
IS - 22
SP - 1
EP - 10
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50658
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Khandarkhaeva, S.
A1 - Bykov, M.
A1 - Fedotenko, T.
A1 - Hanfland, M.
A1 - Sukhikh, A.
A1 - Gromilov, S.
A1 - Dubrovinsky, L.
T1 - Face-centered cubic refractory alloys prepared from single-source precursors
N2 - Three binary fcc-structured alloys (fcc–Ir0.50Pt0.50, fcc Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50) were 14 prepared from [Ir(NH3)5Cl][PtCl6], [Ir(NH3)5Cl][PtBr6], [Rh(NH3)5Cl]2[PtCl6]Cl2 and 15 [Rh(NH3)5Cl][PdCl4]·H2O, respectively, as single-source precursors. All alloys were prepared by 16 thermal decomposition in gaseous hydrogen flow below 800 °C. Fcc–Ir0.50Pt0.50 and fcc–Rh0.50Pd0.50 17 correspond to miscibility gaps on binary metallic phase diagrams and can be considered as 18 metastable alloys. Detailed comparison of [Ir(NH3)5Cl][PtCl6] and [Ir(NH3)5Cl][PtBr6] crystal 19 structures suggests that two isoformular salts are not isostructural. In [Ir(NH3)5Cl][PtBr6], specific 20 Br…Br interactions are responsible for crystal structure arrangement. Room temperature 21 compressibility of fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50 has been investigated up to 50 GPa 22 in diamond anvil cells. All investigated fcc-structured binary alloys are stable under compression. 23 Atomic volumes and bulk moduli show good agreement with ideal solutions model. For fcc–24 Ir0.50Pt0.50, V0/Z = 14.597(6) Å3·atom-1, B0 = 321(6) GPa, B0' = 6(1); for fcc–Rh0.66Pt0.33, V0/Z = 14.211(3) 25 Å3·atom-1, B0 =259(1) GPa, B0' = 6.66(9); for fcc–Rh0.50Pd0.50, V0/Z = 14.18(2) Å3·atom-1, B0 =223(4) GPa, 26 B0' = 5.0(3).
KW - High-pressure
KW - Refractory alloys
KW - Platinum group metals
KW - Single-source precursors
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508176
DO - https://doi.org/10.3390/ma13061418
VL - 13
IS - 6
SP - 1418
PB - MDPI
CY - Basel
AN - OPUS4-50817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Sukhikh, A.
A1 - Kraus, Werner
A1 - Gromilov, S.
T1 - Synthesis and Crystal Chemistry of Octahedral Rhodium(III) Chloroamines
N2 - Rhodium(III) octahedral complexes with amine and chloride ligands are the most common starting compounds for preparing catalytically active rhodium(I) and rhodium(III) species. Despite intensive study during the last 100 years, synthesis and crystal structures of rhodium(III) complexes were described only briefly. Some [RhClx(NH3)6-x] compounds are still unknown. In this study, available information about synthetic protocols and the crystal structures of possible [RhClx(NH3)6−x] octahedral species are summarized and critically analyzed. Unknown crystal structuresof(NH4)2[Rh(NH3)Cl5],trans–[Rh(NH3)4Cl2]Cl·H2O,andcis–[Rh(NH3)4Cl2]Clarereported based on high quality single crystal X-ray diffraction data. The crystal structure of [Rh(NH3)5Cl]Cl2 was redetermined. All available crystal structures with octahedral complexes [RhClx(NH3)6-x] were analyzed in terms of their packings and pseudo-translational sublattices. Pseudo-translation lattices suggest face-centered cubic and hexagonal closed-packed sub-cells, where Rh atoms occupy nearly ideal lattices.
KW - Pseudo-translationalsublattices
KW - Rhodiumcomplexes
KW - Ligandsubstitution
KW - Crystalstructure
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508194
DO - https://doi.org/10.3390/molecules25040768
VL - 25
IS - 4
SP - 768
PB - MDPI
CY - Basel
AN - OPUS4-50819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Domonov, D.
A1 - Pechenyuk, S.
A1 - Belyevskii, A.
T1 - Formation of Nanostructured Carbon from [Ni(NH3)6]3[Fe(CN)6]2
N2 - The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800◦C. Above 600◦C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500°C and is completely oxidized above 700°C.
KW - Carbon materials
KW - Double complex compound
KW - Thermal decomposition
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508188
DO - https://doi.org/10.3390/nano10020389
VL - 10
IS - 2
SP - 389
PB - MDPI
CY - Basel
AN - OPUS4-50818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrand, G.
A1 - Sänger, Johanna Christiane
A1 - Schirmer, U.
A1 - Mantei, W.
A1 - Dupuis, Y.
A1 - Houbertz, R.
A1 - Liefeith, K.
T1 - Process Development for Additive Manufacturing of Alumina Toughened Zirconia for 3D Structures by Means of Two-Photon Absorption Technique
N2 - Additive manufacturing is well established for plastics and metals, and it gets more and more implemented in a variety of industrial processes. Beside these well-established material platforms, additive manufacturing processes are highly interesting for ceramics, especially regarding resource conservation and for the production of complex three-dimensional shapes and structures with specific feature sizes in the µm and mm range with high accuracy. The usage of ceramics in 3D printing is, however, just at the beginning of a technical implementation in a continuously and fast rising field of research and development. The flexible fabrication of highly complex and precise 3D structures by means of light-induced photopolymerization that are difficult to realize using traditional ceramic fabrication methods such as casting and machining is of high importance. Generally, slurry-based ceramic 3D printing technologies involve liquid or semi-liquid polymeric systems dispersed with ceramic particles as feedstock (inks or pastes), depending on the solid loading and viscosity of the system. This paper includes all types of photo-curable polymer-ceramic-mixtures (feedstock), while demonstrating our own work on 3D printed alumina toughened zirconia based ceramic slurries with light induced polymerization on the basis of two-photon absorption (TPA) for the first time. As a proven exemplary on cuboids with varying edge length and double pyramids in the µm-range we state that real 3D micro-stereolithographic fabrication of ceramic products will be generally possible in the near future by means of TPA. This technology enables the fabrication of 3D structures with high accuracy in comparison to ceramic technologies that apply single-photon excitation. In sum, our work is intended to contribute to the fundamental development of this technology for the representation of oxide-ceramic components (proof-of-principle) and helps to exploit the high potential of additive processes in the field of bio-ceramics in the medium to long-term future.
KW - Additive manufacturing
KW - Ceramics 3D printing
KW - Two-photon adsorption
KW - Polymer-ceramic mixtures
KW - Bio-ceramic engineering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526672
DO - https://doi.org/10.3390/ceramics4020017
VL - 4
IS - 2
SP - 224
EP - 239
PB - MDPI
CY - Basel
AN - OPUS4-52667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Bestimmung der Partikelgrößen-verteilung mittels Zentrifugen-Sedimentationsverfahren nach ISO 13318-2 (Küvette)
N2 - Im Vortrag werden das Messprinzip einer Photozentrifuge erläutert und die Anforderungen der zugrundeliegenden Normen diskutiert. Die praktische Durchführung der Messung und insbesondere auch die vorbereitenden Arbeiten, sowie die Auswertung der Rohdaten bilden den Schwerpunkt des Vortrags. Gezeigt werden auch die Validierung sowie ein Beispiel zur regelmäßigen Verifizierung des Verfahrens. Nach Anwendungsbeispielen und Vergleichen zu Ergebnissen mit anderen Messverfahren, wird das Verfahren in einer Zusammenfassung bewertet.
T2 - Seminar Rheologie und Stabilität von dispersen Systemen
CY - Potsdam, Germany
DA - 08.05.2023
KW - CLS
KW - Particle size
KW - Nano
PY - 2023
AN - OPUS4-57679
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 50, Heft 4
T3 - Amts- und Mitteilungsblatt der BAM - 4/2020
KW - Gefahrgutregeln
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
KW - Festlegungen
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527351
SN - 0340-7551
VL - 50
IS - 4
SP - 451
EP - 474
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-52735
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
T1 - How NDT and AI support Reincarnate
N2 - Der Vortrag gibt eine Übersicht über aktuelle zerstörungsfreie Prüfmethoden, die verwendet werden können, um eine Zustandsbewertung von Bauteilen im Bestand vorzunehmen und mögliche Wiederverwendungsstrategien zu entwickeln. Ebenfalls zeigt der Vortrag, welche Möglichkeiten es gibt, künstliche Intelligenzmethoden zu verwenden, um aus recykelten Materialien wieder hochwertige, neue Baustoffe zu entwickeln.
T2 - Stammtisch Nachhaltiges Bauen
CY - Berlin, Germany
DA - 23.05.2023
KW - Recycling
KW - Zerstörungsfreie Prüfung
KW - Kreislaufwirtschaft
KW - Bauteile
KW - Künstliche Intelligenz
PY - 2023
AN - OPUS4-57710
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 51, Heft 2
T3 - Amts- und Mitteilungsblatt der BAM - 2/2021
KW - Anerkennungen
KW - Zulassungen
KW - Gefahrgutregeln
KW - Festlegungen
KW - Richtlinien
KW - Gebührenverordnung
KW - Preis- Leistungsverzeichnis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529061
SN - 0340-7551
VL - 51
IS - 2
SP - 71
EP - 110
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-52906
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - New analytic ways to characterise mesoporous thin layers used in electrocatalytic water splitting
N2 - Mesoporous materials are needed in many applications where a high specific surface area and adsorptive behaviour is needed. Important examples are separation techniques and barrier layers and catalysts. Electrochemical water splitting is the key technology for producing green hydrogen and there is no foreseeable alternative to this process for producing elementary hydrogen from green electrical power. Water electrolysis can be divided into the anodic Oxygen Evolution Reaction (OER) and the cathodic Hydrogen Evolution Reaction (HER). Both processes have to be heavily optimised to a large extent to avoid energy losses caused by overvoltage. The development of electrodes for these processes is especially difficult due to the many boundary conditions. Water splitting is a catalytic as well as electrochemical process. The contact area between the electrolyte and the electrode must be maximised maintaining the stability of the surface. Side reactions must be suppressed, and effective gas transport must be ensured. The whole process has to be tolerant with respect to temperature, harsh chemical conditions from the electrolyte as well as high current densities.
We present a hybrid analytical method combining several analytical techniques for determining the properties of thin layers of mixed oxides of the general composition Ir:TiOx. These materials are promising candidates for electrocatalytical top coatings of OER electrodes. To lower the costs of the electrolysers, the main goal is to lower the Ir content retaining the system efficiency. The main properties which are hard to determine are the porous volume fraction and the Ir:Ti element ratio. By a combination of electron microscopy, spectroscopic operando ellipsometry, ellipsometric porosimetry, and other techniques, we can determine key features of mesoporous thin layer materials. We aim to develop operando capable techniques used in process monitoring as well as measurement techniques optimised for accuracy. By developing reference materials, we support long term uptake of our methodology. This work can directly be used for optimising electrocatalytic layers and is a good example for the power of hybrid metrology for improving materials design.
T2 - International Conference on Resource Chemistry
CY - Alzenau, Germany
DA - 11.03.2024
KW - Ellipsometry
KW - Electrocatalytic Water Splitting
KW - Mesoporous Materials
KW - Electron Probe Microanalysis
KW - Hydrogen Generation
PY - 2024
AN - OPUS4-59764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Surface oxidation accompanying the formation of various types of femtosecond laser-generated surface structures on titanium alloy
N2 - Different types of laser-generated surface structures, i.e., Laser-induced Periodic Surface Structures (LIPSS, ripples), Grooves, and Spikes are generated on titanium and Ti6Al4V surfaces by means of femtosecond (fs) laser scan processing (790 nm, 30 fs, 1 kHz) in ambient air. Morphological, chemical and structural properties of the different surface structures are characterized by various surface analytical techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), Glow discharge optical emission spectroscopy (GD-OES), and depth-profiling Auger electron spectroscopy (AES). It is revealed that the formation of near-wavelength sized LIPSS is accompanied by the formation of a graded oxide extending several tens to a few hundreds of nanometers into depth. GD-OES performed on other superficial fs-laser generated structures produced at higher fluences and effective number of pulses per spot area such as periodic Grooves and irregular Spikes indicate even thicker graded oxide layers. These graded layers may be suitable for applications in prosthetics or tribology.
T2 - E-MRS Spring Meeting 2021
CY - Online meeting
DA - 31.05.2021
KW - Laser-induced periodic surface structures (LIPSS)
KW - Titanium alloy
KW - Oxidation
KW - Glow-discharge optical emission spectroscopy
PY - 2021
AN - OPUS4-52749
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - The role of electromagnetic scattering in the formation of laser-induced periodic surface structures
N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon that is accompanying laser materials processing. These surface nanostructures pave a simple way for surface functionalization with numerous applications in optics, fluidics, tribology, medicine, etc. During the last decade remarkable experimental and theoretical improvements in understanding of their formation mechanisms were obtained - all pointing toward polarization-dependent energy deposition by absorption of optical radiation that is scattered at the surface roughness and interfering with the laser beam. This contribution reviews the current state-of-the-art on the role of electromagnetic scattering in the formation of LIPSS by ultrashort laser pulses. Special attention is drawn to recent finite-difference time-domain (FDTD) calculations that allow to visualize the radiation patterns formed in the vicinity of the sample surface and to the impact of a thin superficial laser-induced oxidation layer.
T2 - E-MRS Spring Meeting 2021
CY - Online meeting
DA - 31.05.2021
KW - Laser-induced periodic surface structures (LIPSS)
KW - Optical scattering
KW - Oxidation
KW - Femtosecond laser
PY - 2021
AN - OPUS4-52729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Angurel, L.A.
T1 - Effects of laser surface processing under different atmospheres on the superconducting properties of pure niobium
N2 - Niobium metal is the pure element with the highest superconducting critical temperature (T_c = 9.2 K), which is present in many applications. Particularly, in superconducting radio frequency (SRF) cavities of particle accelerators, the control of the surface characteristics of pure Nb is crucial, as the presence of defects may generate magnetic flux pinning that can increase by more than two orders of magnitude the surface critical current, ic. Several procedures such as chemical- or electro-polishing have been used aiming at cleaning surface contamination and decreasing its roughness. Sub-nanosecond lasers can be applied to generate a broad range of micro and nanostructures (e.g. Laser-Induced Periodic Surface Structures, LIPSS) that strongly modify the materials properties - as wettability, color, oxidation resistance or antibacterial behavior. In this work, we analyze a variety of surface structures generated on pure Nb sheets with different laser systems (UV, Vis and n-IR, fs and ps) by exploring a range of processing parameters. These include pulse overlap, irradiance or the effective number of pulses, under different atmospheres (air, N2, Ar, vacuum). The effects on Tc, critical currents and critical fields (Bc1, Bc2 and Bc3) have been obtained from magnetization, ac susceptibility and heat capacity measurements, revealing their dependence with the different surface nanostructures and the chemical changes generated with these laser treatments.
T2 - E-MRS Spring Meeting 2021
CY - Online meeting
DA - 31.05.2021
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser ablation
KW - Niobium
KW - Superconductivity
PY - 2021
AN - OPUS4-52730
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Neue Erkenntnisse zur Deckschichtbildung von Zink an der Atmosphäre
N2 - Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
T2 - Sitzung des GfKORR Arbeitskreises „Zink und Zinküberzügel“
CY - Online meeting
DA - 28.09.2021
KW - Atmosphärische Korrosion
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Zink
PY - 2021
AN - OPUS4-53410
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simon, Franz-Georg
T1 - Beschleunigte Alterung von Geotextilien zur Ermittlung von Materialeigenschaften
N2 - Geokunststoffe werden im Wasserbau häufig eingesetzt, beispielsweise bei Maßnahmen für den Küstenschutz oder in Ballastschichten für Windenergieanlagen. Eine zunehmende Anwendung von Geokunststoffen wird aufgrund der Ausweitung der Offshore-Windenergieerzeugung und des Schutzes auf steigende Wasserspiegel und extremere Wetterbedingungen infolge des Klimawandels beobachtet. Die Anwendung von Geokunststoffen in Wasserbauprojekten bietet zwar verschiedene wirtschaftliche und technische Vorteile, wurde jedoch kürzlich in Frage gestellt, da sich diese Materialien während ihrer Lebensdauer verschlechtern und langfristig gefährliche Auswirkungen auf die aquatische Umwelt haben können, insbesondere als Ursprung von Kunststoffabfällen oder als Quelle / Senke für Chemikalien wie Weichmacher und Stabilisatoren, die bei der Herstellung von Geokunststoffen verwendet werden, um deren Leistung zu verbessern. Der Vortrag geht auf diese Bedenken ein.
T2 - Geotextilien im Wasserbau
CY - Online Meeting
DA - 14.04.2021
KW - Wasserbau
KW - Geotextilien
KW - Beschleunigte Alterung
PY - 2021
AN - OPUS4-52434
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tian, H.
T1 - Composition and microstructure stability of cement compound under cyclic hydrothermal condition
N2 - There have been many researches focused on the performance improvement of ultra-high performance concrete (UHPC) by autoclaving treatment. The goal of autoclaving is to increase the pozzolanic reaction, and to densify the cement stone and the transition zone which originates from the incorporation of supplementary cementitious materials (SCMs), such as silica fume, fly ash and blast furnace slag. Due to the superior properties, UHPC can also be utilized under high mechanical load and aggressive condition, for example, the fabrication of water tanks for thermal storage which is of great significance for saving energy and reducing CO2 emission. It is known that mineral stability of the hydration products of an inorganic binder is highly related to the temperature and pressure of the environment. A certain stable composition at room temperature, however, may undergo a phase transformation at high temperature and the performance decrease under this severe condition will generally be more severe. In this way, the rationale behind this deterioration under long-term hydrothermal condition involving many cycles and long duration has to be clarified, and then appropriate optimizing methods will be performed in order to obtain a kind of construction with high durability under aggressive environment. For this purpose, different types and amounts of SCMs are introduced into the standard mixture of UHPC and the phase compositions after autoclaving at 200 °C and 15.5 bar are determined by combined X-ray diffraction and scanning electron microscope. Mercury intrusion porosimeter is used to characterise the microstructure of the samples. In order to establish the relationship between microstructure and macroscopic properties, compressive and flexural strength are also investigated.
T2 - HiPerMat 2020
CY - Kassel, Germany
DA - 11.03.2020
KW - Hydrothermal treatment
KW - UHPC
KW - Composition
PY - 2020
AN - OPUS4-52377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Prozess- und materialbedingte Ursachen für Korrosionserscheinungen an nichtrostenden Stählen
N2 - Der Vortrag beleuchtet prozess- und materialbedingte Ursachen für Korrosionserscheinungen an nichtrostenden Stählen. Der Fokus liegt auf dem Einfluss von Schleifprozessen. Es werden Maßnahmen erläutert, um die Korrosionsbeständigkeit der Oberfläche zu verbessern.
T2 - 3M Webinar „Schleiftechnologien zur Korrosionsvermeidung und Produktivitätssteigerung“
CY - Online meeting
DA - 25.03.2021
KW - Nichtrostender Stahl
KW - Korrosion
KW - Schleifprozesse
PY - 2021
AN - OPUS4-52360
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Process- and material-related causes for corrosion defects on stainless steels
N2 - The presentation provides information on process- and material-related causes for corrosion on stainless steels. The influence of surface grinding is discussed. Methods for enhancing the corrosion resistance of stainless steels are shown.
T2 - 3M Webinar “Technologies, Tools & Tips to avoid corrosion on Stainless Steel”
CY - Online meeting
DA - 25.02.2021
KW - Stainless steel
KW - Corrosion
KW - Grinding processes
PY - 2021
AN - OPUS4-52358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seneschal-Merz, Karine
T1 - New UV-protective glazing for the conservation of cultural assets
N2 - For centuries, churches, secular buildings and museums have been furnished with valuable works of art. Many works of art are UV- and light-sensitive. It is well known that especially UV radiation causes damage and discoloration in paintings, textiles, plastics, wood and other materials. In particular, the wavelengths between 280 and 410 nm cause color changes, embrittlement or destruction of e.g. plastics over time. Therefore, strongly UV-absorbing glasses are advantageous for architecture and are necessary for the protection of cultural assets. As restorers in all disciplines become more and more aware, the demands placed on buildings and their furnishings in terms of climate are becoming increasingly detailed and precise. The aim in each case is to preserve the valuable artwork.
For some years now, the industry has been offering the protection of cultural objects by installing special UV-protective glasses. Currently, UV protection for church buildings is realized by laminated safety glass equipped with appropriate UV-protective plastic films. Technically, this always means a second pane of glass in front of the windows, which is installed outside the building. This creates climatic gaps that are difficult to control and deterioration due to ageing effects can be expected. At the same time, this protective glazing is not invisible and has a considerable aesthetic influence on the interior and exterior appearance of the building. Meanwhile, the preservation of historical monuments accepts such aesthetic cuts on buildings in order to protect the artwork in the interior from UV light. To this day, however, the long-term durability of UV protection provided by inserted plastic films is still controversial.
To date the only available alternative on the market is a mouth-blown UV protection glass which uses a so-called overlay to provide UV protection. This shows that UV protection can also be achieved by glasses without plastic films thus realizing an exclusive inorganic protection which normally is more stable than a polymeric one. So far there are not enough studies to prove long-term durability.
The aim of this project is to provide existing glazing or new glazing to be created with a highly transparent layer that ensures this UV-protective filter function below 400 nm. The glass coating is to be applied to the glass over a large area and fired into the surface like a classic ceramic enamel paint with the same technics. In addition, it should be long-term durable in its function. It means, that the glass has to be fused at temperatures below 630 °C during the firing process, its chemical durability has to be high, its coefficient of thermal expansion has to be as close as the one of the substrate (usually float glass) and the glass has to absorb the UV-radiation within a thin thickness (thinner as 100 µm).
In this project, the long-term durability of commercial UV-protective glasses is examined. New low melting glasses containing UV-absorbing ions are being developed. Their UV-absorption as a thin layer is analyzed as well as their chemical durability and their thermal properties.
We are grateful to BMWI for the financial support in the frame of the Central Innovation Programme for SMEs (ZIM).
T2 - HVG-DGG: 94. Glastechnische Tagung
CY - Online meeting
DA - 10.05.2021
KW - Glass
KW - Low melting
KW - Chemical durability
KW - Weathering tests
KW - Aging test
KW - UV absorption
KW - UV protection
KW - Architecture
KW - Optical properties
PY - 2021
AN - OPUS4-52648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Data processing and nonlinear curve Fitting with fityk
N2 - A brief introduction into fityk is given. The introduction is followed by a pratical session. Fityk is a versatile data processing tool for nonlinear curve fitting.
T2 - AFM Data analysis seminar
CY - Online meeting
DA - 23.02.2021
KW - Fityk
KW - Curve fitting
KW - Analysis
KW - Raman
KW - IR
KW - XPS
PY - 2021
AN - OPUS4-52154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fiedler, Saskia
T1 - Cathodoluminescence of Silicon Nanoparticles
N2 - In this work, Mie resonances in single Si nanoparticles (NPs) of different sizes have been systematically studied, using dark field (DF) and cathodoluminescence (CL) spectroscopy. An analytical method has been developed to compare experiment with theory.
Experimental CL spectra are averaged over entire Si NPs, allowing for direct comparison to DF spectra of identical NPs. Theoretical spectra clarify the assignment of Mie resonances within the NP which contribute with different intensity in DF and CL, resulting in an apparent spectral shift. Furthermore, a substrate effect appears. A 100 nm-Si NP on 15 nm SiN results in a broad peak, spectrally in between that of the calculated electric and magnetic dipole, a NP on 50 nm SiN exhibits two separated peaks as theoretically predicted. High spatial resolution of electron beam excitation allows to study the spectral CL changes at varying beam impact parameters. Theory and experiment agree that depending on beam position within a small Si NP, relative intensity of electric and magnetic dipole change; electric dipole vanishing in the center of the NP. Similar results are found for larger (d = 210 nm) Si NPs although the mode assignment is challenging as higher order modes appear and overlap with others.
In conclusion, comparison of CL and DF spectra is not trivial, in fact, excitation/radiation of distinct Mie resonances within a single Si NP are dependent on beam placement. However, substrate effects need to be considered in CL.
T2 - European Material Research Society Fall Meeting 2021
CY - Online meeting
DA - 20.09.21
KW - Cathodoluminescence
KW - Silicon nanoparticles
KW - Mie resonances
PY - 2021
AN - OPUS4-53439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Botsch, B
T1 - Classification of fracture surface types based on SEM images
N2 - The following work deals with the quantitative fracture surface evaluation in damage analysis. So far, fracture surfaces have almost exclusively been evaluated qualitatively, i.e. the presence of fracture features is documented and their surface proportions are estimated, if necessary. Many years of experience are required, as well as an intensive comparison with defined comparative images from the literature. The aim of this work is the development of classifiers which can recognize fracture mechanisms or fracture features in scanning electron microscope images (SEM). The basis is 46 SEM images, which have been evaluated by fractography experts with regard to fracture features. The existing data set of images is expanded using augmentation methods in order to increase the variability of the data and counteract overfitting. Only convolutional neural networks (CNN) are used to create the classifiers. Various network configurations are tested, with the SegNet achieving the best results.
T2 - Materialsweek 2021
CY - Online meeting
DA - 07.09.2021
KW - Fractography
KW - Fracture surface
KW - Deep learning
KW - SEM
PY - 2021
AN - OPUS4-53418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Bonse, Jörn
ED - Spaltmann, Dirk
T1 - Laser-induced periodic surface nano- and microstructures for tribological applications
N2 - This book is a reprint collection of articles from the Special Issue published online in the open access journal Lubricants.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Friction
KW - Wear
KW - Applications
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516611
UR - https://www.mdpi.com/books/pdfview/book/3130
SN - 978-3-03943-523-4
SN - 978-3-03943-524-1
SP - 1
EP - 180
PB - MDPI
CY - Basel
AN - OPUS4-51661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan-Scherb, Christiane
A1 - Schulz, Wencke
A1 - Schneider, M.
A1 - Karafiludis, Stephanos
A1 - Laplanche, G.
T1 - High-Temperature Oxidation in Dry and Humid Atmospheres of the Equiatomic CrMnFeCoNi and CrCoNi High- and Medium-Entropy Alloys
N2 - Surface degradation phenomena of two model equiatomic alloys from the CrMnFeCoNi alloy system were investigated in 2% O2 and 10% H2O (pO2 = 0.02 and 10−7 atm, respectively) at 800 °C for times up to 96 h. The crystallographic structures, morphologies, and chemical compositions of the corrosion layers developing on CrMnFeCoNi and CrCoNi were comparatively analyzed by mass gain analysis, X-ray diffraction, and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and electron backscatter diffraction. The oxidation resistance of CrMnFeCoNi is relatively poor due to the fast growth of porous Mnoxide(s). CrCoNi forms an external chromia layer that is dense and continuous in a dry 2% O2 atmosphere. This layer buckles and spalls off after exposure to 10% H2O atmosphere. Beneath the chromia layer, a Cr-depleted zone forms in the CrCoNi alloy in both environments. As the oxide scale spalls off in the H2O-containing
atmosphere, a secondary chromia layer was observed and correspondingly enlarges the Cr-depleted zone. In contrast, as the chromia layer remains without significant spallation when CrCoNi is exposed to a dry oxidizing atmosphere, the region depleted in Cr is narrower.
KW - High temperature oxidation
KW - High entropy alloys
KW - Medium entropy alloys
KW - CrMnFeCoNi
KW - CrCoNi
KW - Mn-oxides
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517859
DO - https://doi.org/10.1007/s11085-020-10014-7
SN - 0030-770X
VL - 95
IS - 1-2
SP - 105
EP - 133
PB - Springer
AN - OPUS4-51785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santos, C.I.L.
A1 - Machado, W.S.
A1 - Wegner, Karl David
A1 - Gontijo, L.A.P.
A1 - Bettini, J.
A1 - Schiavon, M.A.
A1 - Reiss, P.
A1 - Aldakov, D.
T1 - Hydrothermal Synthesis of Aqueous-Soluble Copper Indium Sulfide Nanocrystals and Their Use in Quantum Dot Sensitized Solar Cells
N2 - facile hydrothermal method to synthesize water-soluble copper indium sulfide (CIS) nanocrystals (NCs) at 150 degrees C is presented. The obtained samples exhibited three distinct photoluminescence peaks in the red, green and blue spectral regions, corresponding to three size fractions, which could be separated by means of size-selective precipitation. While the red and green emitting fractions consist of 4.5 and 2.5 nm CIS NCs, the blue fraction was identified as in situ formed carbon nanodots showing excitation wavelength dependent emission. When used as light absorbers in quantum dot sensitized solar cells, the individual green and red fractions yielded power conversion efficiencies of 2.9% and 2.6%, respectively. With the unfractionated samples, the efficiency values approaching 5% were obtained. This improvement was mainly due to a significantly enhanced photocurrent arising from complementary panchromatic absorption.
KW - Aqueous quantum dot
KW - Solar cells
KW - CUINS2 nanocrystals
KW - Colloidal semiconductor nanocrystals
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517983
DO - https://doi.org/10.3390/nano10071252
VL - 10
IS - 7
SP - 1252
PB - MDPI
AN - OPUS4-51798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cubero, A.
A1 - Martínez, E.
A1 - Angurel, L.A.
A1 - de la Fuente, G.F.
A1 - Navarro, R.
A1 - Legall, Herbert
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Surface superconductivity changes of niobium sheets by femtosecond laser-induced periodic nanostructures
N2 - Irradiation with ultra-short (femtosecond) laser beams enables the generation of sub-wavelength laser-induced periodic surface structures (LIPSS) over large areas with controlled spatial periodicity, orientation, and depths affecting only a material layer on the sub-micrometer scale. This study reports on how fs-laser irradiation of commercially available Nb foil samples affects their superconducting behavior. DC magnetization and AC susceptibility measurements at cryogenic temperatures and with magnetic fields of different amplitude and orientation are thus analyzed and reported. This study pays special attention to the surface superconducting layer that persists above the upper critical magnetic field strength Hc2, and disappears at a higher nucleation field strength Hc3. Characteristic changes were distinguished between the surface properties of the laser-irradiated samples, as compared to the corresponding reference samples (non-irradiated). Clear correlations have been observed between the surface nanostructures and the nucleation field Hc3, which depends on the relative orientation of the magnetic field and the surface patterns developed by the laser irradiation.
KW - Niobium
KW - Surface superconductivity
KW - Laser-induced periodic surface structures (LIPSS)
KW - Nanostructures
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518462
DO - https://doi.org/10.3390/nano10122525
SN - 2079-4991
VL - 10(12)
IS - Special issue "Laser-generated periodic nanostructures"
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-51846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Vecchiato, Luca
T1 - Fatigue limit estimation of welded joints under constant amplitude uniaxial loading adopting the cyclic R-curve analysis
N2 - Most of the in-service failures of welded structures are due to fatigue damage occurring in the joints. Damage tolerant approaches based on the principles of Fracture Mechanics have been shown to play a key role in this framework, as the fatigue limit is defined by the non-propagating condition of multiple defects at the weld toe. The fatigue limit assessment can be performed using the cyclic R-curve analysis which consists in comparing the driving force of a crack propagating into a component, which depends on the geometry, material and external loads, with its resistance curve, i.e. the cyclic R-curve. The crack propagation occurs whenever the crack driving force is higher than the resistance to fatigue crack propagation, while the crack is arrested in the opposite case. Consequently, this suggests that the fatigue limit of a component is defined as that stress level at which the crack driving force curve is tangent to the crack resistance curve. In the present work, the cyclic R-curve analysis has been adopted for determining the fatigue limit of stress-relieved transverse non-load-carrying joints made of S355 structural steel and subjected to fatigue axial loadings. Experimental tests have been performed to evaluate the fatigue limit of the joints. The driving force, identified by the applied Stress Intensity Factor (SIF), has been evaluated by means of linear elastic finite element analysis taking advantage of the Peak Stress Method for its rapid estimation. Based on the experimental observations that the crack initiation and early crack growth phases in welded joints occur within the Heat Affected Zone (HAZ) the cyclic R-curve has been experimentally derived for both the base metal and HAZ material.
T2 - European Conference on Fracture 2022 (ECF23)
CY - Funchal, Portugal
DA - 27.06.2022
KW - Welded Joints
KW - Fatigue Limit
KW - Cyclic R-curve
PY - 2022
AN - OPUS4-55254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Formation of laser-induced periodic surface structures observed with extreme temporal and spatial resolution
N2 - Laser-induced periodic surface structures (LIPSS) have gained remarkable attention as they represent a universal phenomenon that is often accompanying laser-processing. Such LIPSS enable a plethora of different surface functionalizations for applications in the fields of optics, fluidics, tribology, or medicine. Due to the inherent multiscale nature of processes involved in LIPSS formation, their in-situ observation requires experimental techniques that combine high temporal resolution with the appropriate spatial resolution. In this respect fourth generation light sources, namely short wavelength, short pulse free electron lasers (FELs) are offering new and fascinating possibilities. This work contribution will discuss the results of scattering experiments carried at the FLASH free electron laser at DESY (Hamburg, Germany), which allowed us to resolve laser-induced structure formation at surfaces on the nm to sub-µm length scale and in temporal regimes ranging from ps to several ns with sub-ps resolution. A ps-optical pump / fs-XUV scattering probe scheme was employed to 100 nm thick laser-excited silicon films, while recording snapshots of the transmitted XUV scattering patterns at various delay times after the laser pulse impact. On timescales ranging from hundred ps until several ns almost quantitative agreement was observed between certain features of the recorded scattering patterns and predictions of the first-principles theory of J.E. Sipe and coworkers. Other scattering features appearing with a delay of ~100 ps and lasting for ~1 ns are attributed to capillary surface waves being excited at the laser-melted film material while ablation proceeds. Our superior spatio-temporal resolution experiments allow to uniquely reveal and distinguish early signatures of coherent/plasmonic electromagnetic scattering effects, separately followed by hydrodynamic matter reorganization.
T2 - EMRS Spring Meeting 2023, Symposium L “Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - XUV scattering
KW - Free electron laser
KW - Pump-probe
KW - Capillary waves
PY - 2023
AN - OPUS4-57601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Single Femtosecond Laser Pulse induced Amorphization, Re-crystallization and Native Oxide Removal at Silicon Wafer Surfaces
N2 - Single femtosecond laser pulse induced amorphization, re-crystallization and native oxide layer removal at silicon wafer surfaces of different crystal orientation is studied via spectroscopic imaging ellipsometry, atomic force microscopy, and high-resolution transmission electron microscopy.
T2 - 2023 Conference on Lasers and Electro-Optics/Europe – European Quantum Electronics Conferences
CY - Munich, Germany
DA - 26.06.2023
KW - Femtosecond laser
KW - Laser-induced amorphization
KW - Spectroscopic imaging ellipsometry
KW - Transmission electron microscopy
KW - Native oxide layer
PY - 2023
AN - OPUS4-57829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Sustainability Finding its Way into Flame Retardancy: Food for Thought between Fake Fiction and Future
N2 - Main message: Sustainability, or in other words, exploiting environmental conservation for the economic welfare and prosperity for all, would revolutionise the plastics industry were it to become predominant practice as a linear, fossil-fuel–based economy is switched to a carbon circular economy. Food for though is given by dint of a critical overview of the current trends in sustainable flame-retardant polymeric materials.
Introduction:
Transforming the plastics industry into a carbon circular economy over the next 30 years requires an immediate revolution entailing the development of cutting-edge materials and the planning of future industrial production plants. Hence, the innovative field of flame-retardant polymeric materials should lend its strength to drive this challenge. Visionary solutions are proposed to inspire us, while the implementation of economically feasible concepts can take us forward into the future.
Experimental The synthesis, processing, polymer analysis, thermal analysis, and investigation of fire behaviour from our own research are performed according to the state of the art, mostly in accordance with the pertinent ISO standards. Indeed, some of our equipment is part of the accredited lab; for the other methods we fulfil equivalent quality standards in terms of maintenance, calibration, participation in round robins, etc. Work steps such as the synthesis or preparation of new materials are usually outsourced or done with partners that have the relevant core competence. The talk also presents examples from other groups whose experimental is described in the corresponding scientific papers.
Results and Discussion An overview of current trends towards producing sustainable, flame-retardant polymeric materials is presented, using examples from the literature and by sketching our own projects performed in recent years. The examples are structured along a common theme leading from the use of old and new natural materials with some intrinsic flame retardancy, via flame-retardant biopolymers and biocomposites, to using renewable sources for flame retardants with the objective of exploiting natural sources available as industrial waste streams. Natural flame retardants and adjuvants are highlighted, although the status of most may be assessed as merely motivating our vision. Nevertheless, there are natural material streams finding their way into polymer mass production as fillers, adjuvants, polymers, or renewable educt sources. Natural substances originating from industrial waste streams open the door to sustainable solutions, because they are often available at low cost and avoid competition for land with farming or virgin forests. Aside from this main topic, remarks will address the recycling of flame-retarded polymeric materials; vitrimers are mentioned as a potential material for recyclable thermosets. At the end of the day, only convincing property profiles will prevail both for exploiting renewable sources and circular design, including cost effectiveness, sufficient availability, consistent quality, processibility, mechanical properties, and flame retardancy. However, sustainability must not be merely tolerated as an additional demand, but should instead be recognized as a solution, because sustainability aspires to ensure our economic welfare now and in the future.
Acknowledgement:
The examples shown from own project were supported by funding grants: BMBF WTZ: 01DN16040, DFG Scha 730/19-1, VW-Stiftung: Experiment No: 97437, DFG Scha 730/20-1, BMBF KMU Innovativ 031B1289B.
T2 - 19th European Meeting on Fire Retardant Polymeric Materials (FRPM23)
CY - Dübendorf, Switzerland
DA - 26.06.2023
KW - Renewable
KW - Biocomposite
KW - Sustainable
KW - Circular economy
KW - Natural
PY - 2023
AN - OPUS4-57815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Fraucture mechanics-based probablistic structural integrity assessment for aero-engine turbine disk
N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The aim of this work is to present part of a fracture mechanics-based probabilistic assessment procedure under development which aims at calculating the critical rotational speed of the turbine disk based on the numerical-analytical solutions and regulations for the failure probability. In particular, the rim-peeling failure mode is considered as case study. A semi-circular surface crack is modelled at the most stressed region at the diaphragm of a turbine disk. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of J-integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. The analytical solutions to calculate the crack driving force for the lab representative specimen are used for the Monte Carlo simulations, the result of which has been assessed in the form of a Failure Assessment Diagram (FAD). The results of the probabilistic structural integrity assessment show good agreement between Monte Carlo simulations and certification values for the disk in terms of expected failure mode and value of the critical speed.
T2 - ICF15 - International Conference on Fracture
CY - Atlanta, GA, USA
DA - 12.06.2023
KW - Fracture Mechanics
KW - Failure Assessment Diagram
KW - Finite Element Analysis
KW - Component Assessment
PY - 2023
AN - OPUS4-57727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Probabilistic structural integrity assessment of welded joints
N2 - The fatigue assessment of welded joints requires several input data, which can be subdivided into three categories: geometry, material and loading. The number of input data depends essentially on the complexity of the models employed and on the level of accuracy of the analysis. It is common practice to use safety factors in design to account for the scatter of the input parameters. Nevertheless, overly-conservative factors lead often to unrealistic estimations of fatigue life. This work presents a fracture mechanics-based model for the structural integrity assessment of welded joints under constant amplitude fatigue loading, in which the local geometry at the weld toe and the fatigue crack growth properties are considered statistically distributed. The approach is validated against a large number of experimental data.
T2 - ICF15 - International Conference on Fracture
CY - Atlanta, GA, USA
DA - 12.06.2023
KW - Fatigue
KW - Fracture Mechanics
KW - Weldments
KW - Short crack
KW - Probabilistic Assessment
PY - 2023
AN - OPUS4-57726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jentzsch, Stefan
T1 - Numerical and experimental investigations on metal shear band formation at high strain rates with a Hopkinson bar setup
N2 - The essence of dynamic failure is closely linked to the formation of adiabatic shear bands (ASB), which result from the localization of shear strain under high deformation speeds accompanied by a rapid temperature increase. Understanding this phenomenon is crucial in view of safety issues when impacts of fast rotating machine components (i.e. aircraft turbine blades) may occur. Our contribution addresses both the experimental evidence and characterization of ASBs due to high-speed impact tests at the Split HOPKINSON pressure bar (SHPB) setup and the finite element analysis to determine the parameters of the underlying constitutive model, which is closely related to JOHNSON-COOK (JC) material model.
Experimental investigations were performed on notched shear specimens made of the fine -grained structural steel S690QL and the displacements in the regions affected by shear localization were measured with subset-based local Digital Image Correlation (DIC). The displacement fields, obtained in the SHPB tests, were considered as an objective to validate and to identify the constitutive parameters with. The JC model could reasonably reproduce the displacement distribution. In order to overcome the issues with mesh dependency we provide a nonlocal extension based on the implicit gradient model approach.
T2 - GAMM Annual Meeting 2023
CY - Dresden, Germany
DA - 30.05.2023
KW - Gradient-enhanced damage
KW - Adiabatic shear bands
KW - Split Hopkinson bar
KW - Digital image correlation
KW - Viscoplasticity
KW - Finite element analysis
PY - 2023
AN - OPUS4-57827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Niemz, P.
A1 - Baensch, Franziska
A1 - Brunner, A. J.
ED - Pavalache-Ilie, M.
ED - Curtu, A. L.
T1 - Acoustic Emission Analysis And Synchrotron-based Microtomography of glued shear strength samples from spruce wood
N2 - To better understanding the failure of adhesive joints tensile tests were carried out on miniature test specimens from Norway spruce in the synchrotron. Urea-formaldehyde resin was used as adhesive. e. For comparison purposes, tensile tests were carried out on solid wood and on bonded miniature tensile shear samples with acoustic emission. The acoustic emission signals of all the experiments occurred with classified pattern recognition. This resulted in two classes of signals for each two frequency peaks. One class consisted of the low-frequency and the other of the higher-frequency peak of higher intensity, but this was essentially independent from the structure (solid wood or plywood) and size scale of the test specimens. The influence of the adhesive layers was determined on wood test specimens on laboratory scale and on miniature test specimens with an adhesive layer and selected fiber orientations. This gave evidence that the sound emission signals from the failure of the adhesive layer presumably of the class with low frequency signals peak in the range of services can be assigned.
KW - Wood
KW - Bondline
KW - In-situ test
KW - Acoustic emission
KW - Synchrotron tomography
PY - 2020
DO - https://doi.org/10.31926/but.fwiafe.2020.13.62.1.7
VL - 13
IS - 62 Part 1
SP - 81
EP - 88
PB - Transilvania University Press, Brasov, Romania
CY - Brasov
AN - OPUS4-51010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - New findings on the formation of corrosion product layers on zinc in the atmosphere
N2 - The presentation shows systematic investigations to describe the corrosion and corrosion product formation processes of pure zinc under the climatic conditions currently prevailing in the Federal Republic of Germany. The investigations in their entirety aim at questioning current and establishing new ways of looking at the formation of corrosion products of pure zinc under atmospheric corrosion conditions. Thus, they make a significant contribution in understanding corrosion protection by zinc and zinc coatings. In particular, the focus is placed on the initial stage of the corrosion product formation. A systematic investigation of this time range, which is characterized by very reactive corrosion products, is only made possible by using gel-type electrolytes. The short periods of time at the beginning of weathering is now measurable and their influence on the formation of corrosion products and the kinetics of layer formation describable. By combining the new electrochemical approach with gravimetric, microscopic and analytical methods, new insights could be gained both on a methodic and scientific level.
T2 - 26th International Galvanizing Conference and Exhibition
CY - Rome, Italy
DA - 20.06.2022
KW - Atmospheric Corrosion
KW - Corrosion
KW - Corrosion products
KW - Gel-type electrolytes
KW - Zinc
PY - 2022
AN - OPUS4-55113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Forschungsprojekt RUNOFF: "Neubewertung der Dauerhaftigkeit von Dach- und Fassadenmaterialien und des Eintrags von Schwermetall-Ionen in die Umwelt hervorgerufen durch Runoff„
N2 - Bei Betrachtungen zur Lebensdauer von Metallbauteilen im Bauwesen müssen Korrosions- und Runoff-Vorgänge an der Atmosphäre als verschiedene Reaktionen unterschieden werden. Korrosion ist der Prozess, der von elektrochemischen Reaktionen an der Grenzfläche Metall/Patina kontrolliert wird. Runoff dagegen wird durch chemische Reaktionen an der Grenzfläche Patina/Atmosphäre begünstigt. Mit zunehmender Bewitterungszeit nimmt die Korrosionsgeschwindigkeit stetig ab, während postuliert wird, dass die Geschwindigkeit des Runoffs über die gesamte Zeit konstant bleibt. Dieses Verhalten des Runoffs muss aber zunehmend bezweifelt werden. Die Gesamtmenge an abgezehrtem Metall beinhaltet zwei Bestandteile. Ein Teil wird in die Schicht aus Korrosionsprodukten eingebaut, der andere wird aufgrund von Niederschlägen aus der Patina gelöst. Aus diesem Grund ist die Menge an Zink-Runoff stark abhängig von den Eigenschaften der Korrosionsprodukt- bzw. Patinaschicht und nicht anhand der Zusammensetzung des Metalls abschätzbar. Vorhandene Modelle können die Menge an Runoff, und damit verbunden die Abzehrung einer Schicht aus Zink und Kupfer, sowie den resultierenden Eintrag von Schwermetallionen in die Umwelt nicht mehr darstellen und erklären. Um den Korrosionsschutz an Bauwerken zum einen dauerhaft unter Beachtung von Kostenaspekten und Ressourcenschonung und zum anderen unter ökologischen Gesichtspunkten auslegen zu können, müssen deshalb neue wissenschaftliche Grundlagen erarbeitet und die Mechanismen beschrieben werden.
Das BAM-Forschungsvorhaben RUNOFF widmet sich den Fragestellungen. Der Vortrag gibt einen kurzen Überblick zum Forschungsvorhaben.
T2 - 19. Projektetage der Bauforschung
CY - Online meeting
DA - 22.03.2022
KW - Runoff
KW - Zink
KW - Korrosion
KW - Kupfer
PY - 2022
AN - OPUS4-54580
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Micro- and nanowear of self-mated steel generated and studied with an AFM at the single asperity level
N2 - We show for the first time tribotests performed with self-mated 100Cr6 steel, taking advantage of an AFM, employed as a tribometer for the tribotests as well as for the inspection of wear of both tribopartners. Emphasis is put on the morphology of the scars, on wear particles, and on wear of the “colloidal” particles glued on the AFM cantilever. Measurements demonstrate the possibility of characterizing single asperity events leading to very small wear. We highlight several phenomena, which are elementary key constituents of tribological processes. Such phenomena, probably occurring also at the macroscale, can be detected, identified, and characterized with high spatial and time resolution only at the nanoscale, thus giving insight into conditions and causes of their emergence.
KW - Nanowear
KW - Atomic force microscope
KW - 100Cr6 (AISI 52100) steel
KW - Wear particles
KW - Single asperity contact
KW - Particle transfer
KW - Zero wear
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531389
DO - https://doi.org/10.3389/fmech.2021.722434
SN - 2297-3079
VL - 7
SP - 1
EP - 16
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-53138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, P.
A1 - Ihlemann, J.
A1 - Bonse, Jörn
T1 - Editorial: Special issue "Laser-generated periodic nanostructures"
N2 - The study of laser-fabricated periodic nanostructures is one of the leading topics of today’s photonics research. Such structures on the surface of metals, semiconductors, dielectrics, or polymers can generate new material properties with special functionalities. Depending on the specific material parameters and the morphology of the structures, new devices such as microlasers, optical nanoswitches, optical storage devices, sensors or antifraud features can be realized. Furthermore, laser-generated surface textures can be used to improve the tribological properties of surfaces in contact and in relative motion—to reduce friction losses or wear, to modify the wettability or the cell and biofilm growth properties of surfaces through bioinspired laser engineering, for emerging medical applications, or as decoration elements for the refinement of precious goods.
This Special Issue “Laser-Generated Periodic Nanostructures” focuses on the latest experimental and theoretical developments and practical applications of laser-generated periodic structures that can be generated in a “self-organized” way (laser-induced periodic surface structures, LIPSS, ripples) or via laser interference-based direct ablation (often referred to as direct laser interference patterning, DLIP). We aimed to attract both academic and industrial researchers in order to collate the current knowledge of nanomaterials and to present new ideas for future applications and new technologies. By 8 August 2021, 22 scientific articles have been published in the Special Issue, see www.mdpi.com/journal/nanomaterials/special_issues/laser-generated_periodic.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Direct laser interference patterning (DLIP)
KW - Surface functionalization
KW - Laser ablation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530980
DO - https://doi.org/10.3390/nano11082054
SN - 2079-4991
VL - 11
IS - 8
SP - 1
EP - 7
PB - MDPI
CY - Basel
AN - OPUS4-53098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weise, Frank
A1 - Fladt, Matthias
T1 - Innenhydrophobierung - neuartige AKR-Vermeidungsstrategie bei Betonfahrbahndecken
N2 - Um die zunehmenden AKR-Schäden an Betonfahrbahnen im deutschen Autobahnnetz zukünftig zu vermeiden, wurden mit dem ARS 04/2013 verbindliche Eignungsprüfungen zum Ausschluss alkaliempfindlicher Gesteinskörnungen bei Neubau- und Erhaltungsmaßnahmen eingeführt. Dies führte zu einer deutlichen Reduzierung der geeigneten Gesteinskörnungen. Vor diesem Hintergrund soll durch die Zugabe eines Innenhydrophobierungsmittels während der Betonherstellung grenzwertig alkaliempfindliche Gesteinskörnung nutzbar gemacht werden.
Die AKR-Vermeidungsstrategie basiert dabei auf der signifikanten Reduzierung des Eindringens von Wasser und Tausalzlösung in den Fahrbahndeckenbeton. In einem im Aufträge der BASt an der BAM durchgeführten Forschungsvorhaben wurde die Leistungsfähigkeit verschiedener Hydrophobierungsmittel für diesen Einsatzzweck
grundhaft untersucht. In dem Beitrag wird exemplarisch die Leistungsfähigkeit eines geeigneten Hydrophobierungsmittels in einem Waschbeton mit einer sehr alkaliempfindlichen Grauwacke aufgezeigt. Das Spektrum der Laboruntersuchungen reicht dabei von AKR-Betonversuchen mit Alkalizufuhr sowie den aufbauend durchgeführten mikroskopischen Untersuchungen zur Bewertung des AKR-Schädigungspotenzials über die Analyse des Feuchte- und Tausalzeintrags bis zur Ermittlung der mechanischen Eigenschaften und des Frost-Tausalz-Widerstands.
Abschließend wird der noch vorhandene Forschungsbedarf zur Überführung dieser neuen AKR-Vermeidungsstrategie in die Praxis aufgezeigt.
N2 - In order to avoid the increasing ASR damage to concrete pavements in the German motorway network in the future, binding suitability tests for the exclusion of alkali-sensitive aggregates in new construction and maintenanee measures were introduced with ARS 04/2013. This led to a significant reduetion in the number of suitable aggregates. Against this background, borderline alkali-sensitive aggregates are to be made usable by adding an internal water repellent during concrete easting.
The ASR avoidance strategy is based on the signifi-cant reduetion of the penetration of water and de-icing salt solution into the concrete pavement. In a research project carried out at BAM on behalf of the BASt, the performance of various hydrophobing agents for this application was thoroughly investigated. In this contribution, the performance of a suitable water repellent in an exposed aggregate concrete with a very alkali-sensitive greywacke is shown as an example. The spectrum of laboratory investigations ranges from ASR concrete tests with alkali supply and the microscopic investigations carried out to evaluate the ASR damage potential, to the analysis of the moisture and de-icing salt penetration, to the determination of the mechanical properties and the freeze-thaw resistance. Finally, the still existing need for research for the transfer of this new ASR prevention strategy into practice is shown.
KW - Betonfahrbahndecke
KW - Alkali-Kieselsäure-Reaktion
KW - Innenhydrophobierung
PY - 2021
SN - 0039-2162
IS - 9.2021
SP - 730
EP - 738
PB - Kirschbaum Verlag GmbH
AN - OPUS4-54554
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Jörg F.
A1 - Robens-Radermacher, Annika
A1 - Tamsen, Erik
T1 - Data provenance - from experimental data to trustworthy simulation models and standards
N2 - FAIR (findable, accessible, interoperable and reusable) data usage is one of the main principals that many of the research and funding organizations include in their strategic plans, which means that following the main principals of FAIR data is required in many research projects. The definition of data being FAIR is very general. When implementing that for a specific application or project or even setting a standardized procedure within a working group, a company or a research community, many challenges arise. In this contribution, an overview about our experience with different methods and tools is outlined.
We begin with a motivation on potential use cases for the application of FAIR data with increasing complexity starting from a reproducible research paper over collaborative projects with multiple participants such as Round-Robin tests up to data-based models within standardization codes, applications in machine learning or parameter estimation of physics-based simulation models.
In a second part, different options for structuring the data (including metadata schema) are discussed. The first one is the openBIS system, which is an open-source lab notebook and PostgreSQL based data management system. A second option is a semantic representation using RDF based on ontologies for the domain of interest.
In a third section, requirements for workflow tools to automate data processing are discussed and their integration into reproducible data analysis is presented with an outlook on required information to be stored as metadata in the database.
Finally, the presented procedures are exemplarily demonstrated for the calibration of a temperature dependent constitutive model for additively manufactured mortar. A metadata schema for a rheological measurement setup is derived and implemented in an openBIS database. After a short review of a potential numerical model predicting the structural build-up behavior, the automatic workflow to use the stored data for model parameter estimation is demonstrated.
KW - FAIR data
KW - Semantic web
KW - Scientific workflows
KW - Metadata
KW - Reproducible data processing
PY - 2023
DO - https://doi.org/10.1016/j.matpr.2023.08.081
SP - 1
EP - 10
PB - Elsevier
AN - OPUS4-58215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Weise, Frank
A1 - Fladt, Matthias
A1 - Meyer, I.
T1 - Bewertung der Innenhydrophobierung von Fahrbahndeckenbetonen als neuartige AKR-Vermeidungsstrategie
T1 - Evaluation of internal water-repellent treatment of concrete pavements as a novel AAR preventive measure
N2 - Zur Nutzbarmachung grenzwertig alkaliempfindlicher Gesteinskörnungen für Betonfahrbahndecken wurde basierend auf einer Literaturrecherche die Eignung von je einem Innenhydrophobierungsmittel auf der Basis eines Kalziumstearats (HM-A), eines Silan-Siloxan-Gemisches (HM-B) sowie eines der Vertraulichkeit unterliegenden Wirkstoffs (HM-C) für die neuartige AKR-Vermeidungsstrategie untersucht. Die Basis für die Eignungsuntersuchungen bildeten die Rezepturen im ARS 04/2013 für den OB (D>8)/UB sowie für den OB 0/8. Zur Herausarbeitung des Einflusses des Hydrophobierungsmittels auf die schädigende AKR fand in der groben Kornfraktionen ein alkaliempfindlicher Grauwackesplitt Anwendung. Aufgrund der unterschiedlichen Wechselwirkung zwischen dem LP-Bildner und dem Hydrophobierungsmittel wurde seine Dosierung beim HM-A reduziert sowie beim HM-B geringfügig und beim HM-C um ein Vielfaches erhöht.
Ausgehend von den ausgewählten Rezepturen mit den unterschiedlichen Hydrophobierungsmitteln wurden bei den Untersuchungen u.a. folgende Erkenntnisse gewonnen:
• Nachweis der Funktionalität aller drei Hydrophobierungsmittel im Festbeton durch signifikant reduzierte kapillare Aufnahme der Prüflösung.
• Verschlechterung der mechanischen Eigenschaften und des Frost-Tausalzwiderstands des OB (D>8)/UB bei Zugabe aller Hydrophobierungsmittel.
• Verzicht auf den Einsatz des HM-A im OB (D>8)/UB aufgrund drastischer Verschlechterung der Verarbeitbarkeit des Frischbetons und hohem Festigkeitsverlust.
• Verzicht auf den Einsatz des HM-B im OB (D>8)/UB aufgrund der Überschreitung des Dehnungsgrenzwerts nach dem 9. bzw. 10. Zyklus (mit bzw. ohne zyklischer Vorschädigung) und der einhergehenden starken Abwitterung bei der KWL mit NaCl-Lösung.
• Nachweis nachhaltiger Verminderung schädigender AKR in beiden Betonarten mit HM-C in Klimawechsellagerung und 60°C-Betonversuch mit externer Alkalizufuhr, allerdings zu Lasten der mechanischen Eigenschaften und des Frost-Tausalz-Widerstands.
Fazit: Bei geeigneter Wirkstoffauswahl hat die Innenhydrophobierung das Potenzial für die Nutzbarmachung grenzwertiger Gesteinskörnung. Ihre Überführung in die Praxis erfordert jedoch eine weitere ganzheitliche Optimierung der Baustoffperformance. Das schließt auch die Verifizierung gezielter betontechnologischer Maßnahmen zur Verminderung der Verschlechterung der mechanischen Eigenschaften und des Frost-Tausalz-Widerstandes ein.
N2 - In order to enable utilization of borderline-acceptable alkali-sensitive aggregates for concrete road pavements, the applicability of an internal hydrophobic treatment for a novel alkali-aggregate reaction (AAR) preventive measure was investigated. On the basis of a literature review, a calcium stearate (HM-A), a silane-siloxane emulsion (HM-B) and an active agent (HM-C), which is subject to confidentiality, were investigated. The mix designs from ARS 04/2013 for OB (D>8)/UB as well as for OB 0/8 formed the basis for the qualification tests. In order to shed light on the influence of the hydrophobic agent on the damaging AAR, alkali-sensitive greywacke chippings were used as the coarse grain aggregates. Due to the varying interaction between the air-entraining agent and the hydrophobic agent, the hydro-phobic agent dosage was reduced for HM-A, increased slightly for HM-B and increased many times over for HM-C.
Based on the selected concrete mixes with the different hydrophobic agents the following findings were obtained:
• Proof of the functionality of all three hydrophobic agents in hardened concrete by significantly reduced capillary absorption of the test solution.
• Deterioration of the mechanical properties and the resistance to freeze-thaw with de-icing salt of the OB (D>8)/UB through the addition of all hydropho-bic agents.
• The use of HM-A in OB (D>8)/UB should be avoided because of drastic deterioration of the workability of the fresh concrete and significant loss of strength.
• The use of HM-B in OB (D>8)/UB was abandoned due to the exceeding of the expansion limit value from the 9th or 10th cycle onwards (with or without cyclical pre-damage) and the accompanying severe scaling during the cyclic climate storage test (CCST) with NaCl solution.
• Proof of sustainable reduction of harmful AAR in both types of concrete with HM-C in CCST and 60°C concrete prism tests with external alkali supply.
The disadvantage is deterioration of the mechanical properties and the resistance to freeze-thaw with de-icing salt.
Conclusion: With a suitable selection of hydrophobic agent, internal waterrepellent treatment has the potential to enable utilization of borderline-acceptable alkali-sensitive aggregates. However, its transfer into practice re-quires a further holistic optimization of the building material performance. This includes the verification of specific concretetechnological measures to improve both, the mechanical properties and the resistance to freeze-thaw with de-icing salt.
KW - Tausalzeintrag
KW - Betonfahrbahndecke
KW - Alkali-Kieselsäure-Reaktion
PY - 2022
SN - 978-3-95606-643-6
SN - 0344-0788
VL - 1141
SP - 1
EP - 281
PB - Fachverlag NW in der Carl Ed. Schünemann KG
CY - Bremen
AN - OPUS4-54757
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maasch, Philipp
T1 - Numerical Modelling of Deformation-Induced Martensitic Transformation in Additively Manufactured 316L Stainless Steel under Cryogenic Conditions
N2 - Cryogenic structural components, including collars, bladders, and keys for superconducting magnets, as well as elements for liquid hydrogen storage systems, are often fabricated from austenitic stainless steel (e.g., 316L) due to favorable mechanical properties and corrosion resistance. However, producing these complex geometries through traditional methods is challenging. Additive manufacturing presents a promising alternative, though the numerical understanding of material behavior under extreme cryogenic conditions remains limited. This study advances the numerical simulation of deformation-induced martensitic transformation (DIMT) in additively manufactured fused filament fabricated (FFF) 316L stainless steel. Central to this effort is the prediction of tensile behavior at temperatures ranging from ambient down to 4K. Supporting experiments—including tensile tests and microstructural characterization via scanning electron microscopy (SEM) and computed tomography (CT)—provide essential input parameters and validation data for the numerical framework. The numerical modelling in this study is based on a nonlinear, temperature-dependent finite element approach incorporating a newly developed constitutive material law. This law couples a phase-kinetic description of the martensitic transformation with a mixed kinematic/isotropic plastic hardening formulation. By solving the underlying conservation laws and boundary conditions while considering temperature-dependent material parameters, the model provides a realistic representation of stress-strain states and evolving martensitic phase fractions across a wide range of thermal conditions. The implementation within a commercial finite element software relies on user-defined subroutines that integrate the constitutive relations and transformation kinetics. The simulations use adaptive time-stepping and iterative strategies to handle highly nonlinear, cryogenic loading scenarios efficiently. After parameter identification through experimental data, the numerical results are systematically compared with measured values from tensile tests and microstructural analyses. This iterative validation process continuously enhances the predictive capability of the model. By merging advanced material-theoretical concepts with robust numerical methods, the presented framework offers deeper insight into the mechanical behavior of additively manufactured austenitic steels under extreme thermal conditions. Ultimately, it supports the targeted design and optimization of cryogenic lightweight components and contributes to the fundamental understanding of material modeling challenges in applied mechanics.
T2 - 95th GAMM 2025 Poznan
CY - Poznan, Poland
DA - 07.04.2025
KW - Constitutive Modelling
KW - Deformation-induced martensitic transformation
KW - Cryogenic Conditions
KW - Fused Filament Fabrication
KW - Austenitic stainless steel 316L
PY - 2025
AN - OPUS4-63198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
T1 - Friction and mechanical properties of AFM-scan-induced ripples in polymer films
N2 - In the present paper, friction and mechanical properties of AFM-Scan-Induced ripple structures on films of polystyrene and poly-n-(butyl methacrylate) are investigated. Force volume measurements allow a quantitative analysis of the elastic moduli with nanometer resolution, showing a contrast in mechanical response between bundles and troughs. Additionally, analysis of the lateral cantilever deflection shows a clear correlation between friction and the sample topography. Those results support the theory of crack propagation and the formation of voids as a mechanism responsible for the formation of ripples. This paper also shows the limits of the presented measuring methods for soft, compliant, and small structures.
KW - AFM
KW - Polymer
KW - Ripples
KW - Mechanical properties
KW - Friction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532772
DO - https://doi.org/10.3389/fmech.2021.672898
SN - 2297-3079
VL - 7
SP - 1
EP - 8
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-53277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Gräf, S.
T1 - Ten Open Questions about Laser-Induced Periodic Surface Structures
N2 - Laser-induced periodic surface structures (LIPSS) are a simple and robust route for the nanostructuring of solids that can create various surface functionalities featuring applications in optics, medicine, tribology, energy technologies, etc. While the current laser technologies already allow surface processing rates at the level of m2/min, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry, as well as by limitations in controlling the processing of LIPSS and in the long-term stability of the created surface functions. This Perspective article aims to identify some open questions about LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, we intend to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Industrial application
KW - Functional properties
KW - Surface functionalization
KW - Modelling
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539503
DO - https://doi.org/10.3390/nano11123326
SN - 2079-4991
VL - 11
IS - 12
SP - 1
EP - 21
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-53950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiele, Marc
A1 - Pirskawetz, Stephan
T1 - Analysis of damage evolution in concrete under fatigue loading by acoustic emission and ultrasonic testing
N2 - The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.
KW - Concrete
KW - Fatigue
KW - Damage evolution
KW - Ultrasonic testing
KW - Acoustic emission
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541891
DO - https://doi.org/10.3390/ma15010341
SN - 1996-1944
VL - 15
IS - 1
SP - 341
EP - 355
PB - MDPI
CY - Basel
AN - OPUS4-54189
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruns, Sebastian
T1 - Digitalizing a lab course for undergraduate students: ELN, ontology, data management
N2 - We report about a joint project aiming at the digitalization of a lab course in materials testing. The undergraduate students were asked to prepare samples of a precipitation hardened aluminum alloy and characterize them using hardness and tensile tests. In a first step, we developed the frames for the digital labor notebook using eLabFTW. The primary data and the relevant metadata of each run were saved in a central database and made available for analysis and report issues. The whole set of results produced in a course was made available in the database. This database can be improved and serve as an open repository for data on this specific alloy.
The logical frame for the joint project was provided by the PMD Core Ontology (PMDco), a mid-level ontology that enables the representation and description of processes and process chains in an MSE-specific manner, ensuring full traceability of generated data. For the digitalization of this lab course, the tensile test ontology (TTO) was applied which is designed as a module of the PMDco using strongly related semantic concepts.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Electronic Lab Notebook
KW - FAIR data management
KW - Digtial Representation
KW - Knowledge graph and ontologies
PY - 2023
AN - OPUS4-58207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 52, Heft 1
T3 - Amts- und Mitteilungsblatt der BAM - 1/2022
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545287
SN - 0340-7551
VL - 52
IS - 1
SP - 1
EP - 54
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54528
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 52, Heft 2
T3 - Amts- und Mitteilungsblatt der BAM - 2/2022
KW - Festlegungen
KW - Zulassungen
KW - Richtlinien
KW - Anerkennungen
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550917
SN - 0340-7551
VL - 52
IS - 2
SP - 55
EP - 158
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-55091
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lindemann, Franziska
T1 - Bestimmung der spezifischen Oberfläche mittels Gasadsorption (BET-Verfahren)
N2 - Im Rahmen des 2. BAM-Akademie Info-Tages "Nano or not Nano" wurde die OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" vorgestellt.
Der Vortrag beschreibt die Bestimmung der spezifischen Oberfläche von dispersen und/oder porösen Pulvern mittels Gasadsorption nach dem BET-Verfahren.
Es wird auf die Anwendbarkeit der Methode eingegangen und es werden praktische Hinweise zur Probenvorbereitung und Messung von Nanomaterialien gegeben.
T2 - BAM Akademie II: Info-Tage "Nano or not Nano"
CY - Online meeting
DA - 25.01.2024
KW - OECD TG 124
KW - Nanopulver
KW - VSSA
KW - Nano powder
KW - BET
KW - Spezifische Oberfläche
PY - 2024
AN - OPUS4-59623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Innovation und Sicherheit durch Einsatz von Duplexstählen in Straßentunneln
N2 - Es werden die Ergebnisse eines mehrjährigen Forschungsvorhabens der BAM in Zusammenarbeit mit Straßenbauverwaltungen der Länder und Industriebeteiligten zur betriebstechnischen Ausrüstung von Straßentunneln präsentiert. Schwerpunkte waren die Bestimmung der Korrosivität der Atmosphäre von 3 ausgewählten Straßentunneln, die Analyse korrosionsrelevanter Ablagerungen und von Klimadaten. Die Auswirkungen dieser Einflussgrößen auf die Dauerhaftigkeit von Konstruktionen aus nichtrostenden Stählen wurde ermittelt und in Abhängigkeit verschiedener Einflussparameter dargestellt. Die Ergebnisse der systematischen Untersuchungen an Prüfköpern decken sich mit Beobachtungen an realen Bauteilen. Spaltbehaftete Konstruktionen aus Werkstoffen der CRC III führen demnach in Zeiträumen zwischen 10 und 15 Jahren zu Korrosionserscheinungen, welche die technische Sicherheit beeinträchtigen können und die erwartete Dauerhaftigkeit nicht erfüllen. Die Folge sind zusätzliche Sperrungen und ein vorzeitig notwendiger Unterhaltsaufwand, die erhebliche Kosten verursachen. Im Ergebnis ist eine Überarbeitung des aktuellen Regelwerkes erforderlich, um die angestrebte Dauerhaftigkeit von 30 Jahren zu gewährleisten.
T2 - Sitzung ISER Marketingausschuss
CY - Dusseldorf, Germany
DA - 24.04.2024
KW - Korrosion
KW - Straßentunnel
KW - Dauerhaftigkeit
KW - Nichtrostender Stahl
PY - 2024
AN - OPUS4-59955
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Porta-Velilla, L.
A1 - Turan, N.
A1 - Cubero, Á.
A1 - Shao, W.
A1 - Li, H.
A1 - de la Fuente, G.F.
A1 - Martínez, E.
A1 - Larrea, Á.
A1 - Castro, M.
A1 - Koralay, H.
A1 - Çavdar, Ş.
A1 - Bonse, Jörn
A1 - Angurel, L.A.
T1 - Highly Regular Hexagonally-Arranged Nanostructures on Ni-W Alloy Tapes upon Irradiation with Ultrashort UV Laser Pulses
N2 - Nickel tungsten alloy tapes (Ni—5 at% W, 10 mm wide, 80 µm thick, biaxially textured) used in second-generation high temperature superconductor (2G-HTS) technology were laser-processed in air with ultraviolet ps-laser pulses (355 nm wavelength, 300 ps pulse duration, 250–800 kHz pulse repetition frequency). By employing optimized surface scan-processing strategies, various laser-generated periodic surface structures were generated on the tapes. Particularly, distinct surface microstructures and nanostructures were formed. These included sub-wavelength-sized highly-regular hexagonally-arranged nano-protrusions, wavelength-sized line-grating-like laser-induced periodic surface structures (LIPSS, ripples), and larger irregular pyramidal microstructures. The induced surface morphology was characterized in depth by electron-based techniques, including scanning electron microscopy (SEM), electron back scatter diffraction (EBSD), cross-sectional transmission electron microscopy (STEM/TEM) and energy dispersive X-ray spectrometry (EDS). The in-depth EBSD crystallographic analyses indicated a significant impact of the material initial grain orientation on the type of surface nanostructure and microstructure formed upon laser irradiation. Special emphasis was laid on high-resolution material analysis of the hexagonally-arranged nano-protrusions. Their formation mechanism is discussed on the basis of the interplay between electromagnetic scattering effects followed by hydrodynamic matter re-organization after the laser exposure. The temperature stability of the hexagonally-arranged nano-protrusion was explored in post-irradiation thermal annealing experiments, in order to qualify their suitability in 2G-HTS fabrication technology with initial steps deposition temperatures in the range of 773–873 K.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser processing
KW - Hexagonally-arranged nano-protrusions
KW - Second-generation high temperature superconductor technology
KW - Electron microscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552551
DO - https://doi.org/10.3390/nano12142380
SN - 2079-4991
VL - 12
IS - 14
SP - 1
EP - 23
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
T1 - Curtain Walls with Biofilms for Improving the City Climate
N2 - Building envelopes & natural rock surfaces represent the frontier between solid material surfaces, biosphere and the atmospheric environment – and are subject to permanent change in structure and chemistry. These surfaces are a natural habitat of subaerial rock biofilms (SAB) that are an important stage of primary succession. As their metabolic processes have a great impact on the composition of the near-surface layers of the earth biofilms on natural and manmade hard substrates are a research focus of geomicrobiology. In technical systems immobilized algae biofilms are already used successfully for wastewater cleaning. Algae can eliminate bacteria from the water and at the same time increase the oxygen concentration and the pH value in the water through photosynthesis, which again allows phosphate elimination to take place. Nitrificants contained in the algae biofilm convert ammonium to nitrite and nitrate.
Mineral claddings for building facades could be engineered to sustain either natural or previously established carefully selected algae-dominated biofilms and this way help to clean the air.
For a targeted engineering of the mineral substrates and the biofilms attached to them basic knowledge is however missing. By systematic research in an interdisciplinary team of microbiologists and building material scientists the following questions shall be clarified
• How can a curated biofilm be stabilized on the surface and designed to be durable without compromising the substrate
• What exactly do the biofilms need in terms of moisture in their respective growth stages? Or how long water must be available in what form and quantity to enable growth.
• What is the influence of the substrate on the availability and quality of the (rain) water (water quality, leaching of substances (alkalis) from the building materials, leaching of aerosol components, surface tension, suction tension, thickness of the water molecule layers adsorbed in the pore spaces....)
There are several research groups working on bioreceptive building materials which emphasizes the general interest in the topic. The idea of speeding-up the process by the targeted establishment of biofilms on building façade panels is a unique approach that has so far only been researched at BAM. Architects are very interested in biofilm facades as a new co-designing method of humans and nature reflecting the changing awareness for the loss of biodiversity in cities. If the biofilms need irrigation the evaporative cooling would reduce the urban heat island effect.
T2 - Preparatory Workshop SPP 2451: Engineered Living Materials with Adaptive Functions
CY - Saarbrücken, Germany
DA - 10.07.2023
KW - Engineered living materials
KW - Adaptive functions
KW - Bioreceptivity
KW - Biofilm
KW - Concrete
PY - 2023
UR - https://spp2451.de/event/preparatory-workshop/
AN - OPUS4-58965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
T1 - Biorezeptiver Beton: Interdisziplinäre Forschung an der BAM
N2 - Inhalt des Vortrags: Forschungsidee und Zielstellung, Forschungsstruktur, Veränderung, Wasserverfügbarkeit, Wasserrückhaltevermögen, pH-Wert, Speziesauswahl, Applikation, Monitoring von Bewuchs
T2 - BDA Galerie, Ausstellung: wechselStoffwechsel, Galeriegespräch Nr. 3
CY - Berlin, Germany
DA - 06.06.2023
KW - Biorezeptivität
KW - Beton
KW - Biofilm
KW - Funktionalisierung
KW - Fassade
PY - 2023
UR - https://www.bda-berlin.de/events/wechsel-stoff-wechsel-gespraech-3/
AN - OPUS4-58961
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kalinka, Gerhard
T1 - Testing the fibre matrix interface of short glass fibre reinforced PMCs with using the push out technique
N2 - With this presentation, the push-out technique is explained. The focus of the experimental work is on the characterization of the fiber-matrix interface of short fiber reinforced composites. The reinforcing component was glass fibers and the matrix polymer was PA6.6 and PPA.
It is demonstrated for the first time that the push-out technique ca be applied on injection molded short fiber PMC and is sensitive to the mechanical interface properties. Further studies are planned on the influence of multiple processing, the temperature and humidity.
T2 - Composirtes United Workshop „Fiber Matrix Interphases“
CY - Online meeting
DA - 09.11.2023
KW - Polymer Matrix Composite
KW - Glass Fibres
KW - PA6.6
KW - PPA
KW - Push-out Test
KW - Interface Strength
PY - 2023
AN - OPUS4-59053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Simon, Franz-Georg
A1 - Scholz, Philipp
A1 - Barqawi, Haitham
T1 - Einfluss von Geokunststoffen auf die aquatische Umwelt
N2 - Im Rahmen des Projekts konnte gezeigt werden, dass Geokunststoffe bei ausreichender Stabilisierung Einsatzdauern von über 100 Jahren besitzen. Es werden keine Stoffe freigesetzt, die für Wasserorganismen schädlich sind. An den Ostseestränden im Gebiet Kaliningrad werden nennenswerte Mengen von Kunststoffresten gefunden, die zum Teil aus Küstenschutzbauwerken stammen. Ursache ist hier jedoch eine verfehlte Materialauswahl. Hauptsächlich stammen die Kunststoffreste am Strand jedoch aus unsachgemäße Abfallbehandlung.
KW - Geokunststoffe
KW - Mikroplastik
KW - Autoklaventest
KW - Ökotoxtests
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556431
DO - https://doi.org/10.2314/KXP:1813230285
SP - 1
EP - 15
AN - OPUS4-55643
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 51, Heft 4
T3 - Amts- und Mitteilungsblatt der BAM - 4/2021
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541902
SN - 0340-7551
VL - 51
IS - 4
SP - 135
EP - 158
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54190
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Ellipsometry as a production measurement tool
N2 - Spectroscopic Ellipsometry is an enormously versatile measurement tool for surfaces and thin layers. We discuss the use of ellipsometry in the context of quality control in production processes of eletrconic devices.
T2 - Photonics Days Berlin Brandenburg
CY - Berlin, Germany
DA - 09.10.2023
KW - Ellipsometry
KW - Quality control
KW - Metrology
PY - 2023
AN - OPUS4-59837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
T1 - Multi-scale optical imaging methods for quality control of electronic devices
N2 - The presentation demonstrates an application of multi-scale optical imaging methods such as spectroscopic imaging ellipsometry and white light interference microscopy for the investigation of wide-bandgap semiconductors for power electronics. The capabilities of these methods for the development of new reference calibration samples for scanning microwave microscopes (SMM) and conductive atomic force microscopes (C AFM) are discussed.
T2 - Photonics Days Berlin Brandenburg 2023
CY - Berlin, Germany
DA - 09.10.2023
KW - Imaging ellipsometry
KW - White light interference microscopy
KW - Power electronics
KW - Reference standards
KW - Metrology
KW - Nanoelectronics
PY - 2023
AN - OPUS4-59838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qiao, Linan
A1 - Nagelschmidt, Sven
A1 - Herbrich, Uwe
A1 - Keller, Christian
T1 - Introduction of a Power Law Time-Temperature Equivalent Formulation for the Description of Thermorheologically Simple and Complex Behavior
N2 - Abstract: In this work, a conceptual framework is suggested for analyzing thermorheologically simple and complex behavior by using just one approach. Therefore, the linear relation between master time and real time which is required in terms of the time-temperature superposition principle was enhanced to a nonlinear equivalent relation. Furthermore, we evaluate whether there is any relation among well-known existing time-temperature equivalent formulations which makes it possible to generalize different existing formulations. For this purpose, as an example, the power law formulation was used for the definition of the master time. The method introduced here also contributes a further framework for a unification of established time-temperature equivalent formulations, for example the time-temperature superposition principle and time-temperature parameter models. Results show, with additional normalization conditions, most of the developed time-temperature parameter models can be treated as special cases of the new formulation. In the aspect of the arrow of time, the new defined master time is a bended arrow of time, which can help to understand the corresponding physical meaning of the suggested method.
KW - bended arrow of time
KW - time-temperature superposition principle
KW - time-temperature equivalent formulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543800
DO - https://doi.org/10.3390/ma15030726
VL - 15
IS - 3
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-54380
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Korrosionsprüfung
N2 - Der Vortrag gibt einen Überblick über gängige Korrosionsversuche. Die wesentlichen Unterschiede zwischen Prüf- und Untersuchungsverfahren, deren jeweilige Zielstellung, Aussagefähigkeit und Grenzen werden aufgezeigt. Es werden ausgewählte Auslagerungsversuche, Kammerprüfungen sowie elektrochemische Messmethoden zur Bestimmung der Korrosionsbeständigkeit vorgestellt. Anhand praktischer Beispiele werden ausgewählte Ergebnisse der einzelner Methoden vorgestellt und diskutiert.
T2 - VDEh Seminar "Korrosionsverhalten nichtrostender Stähle in wässrigen Medien und bei atmosphärischer Beanspruchung*
CY - Düsseldorf, Germany
DA - 30.01.2024
KW - Korrosion
KW - Korrosionsversuche
KW - Nichtrostender Stahl
PY - 2024
AN - OPUS4-59553
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Bestimmung der Skelettdichte mittels Gaspyknometrie
N2 - Im Rahmen des 2. BAM-Akademie Info-Tages "Nano or not Nano" wurde die OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" vorgestellt. Der Vortrag beschreibt detailliert das Messverfahren der He-Gaspyknometrie zur Bestimmung der Skelettdichte von Pulvern und geht auf Anwendbarkeit, Besonderheiten bei Nanopulvern und wichtige Einstellparameter für die Messung ein.
T2 - BAM Akademie II: Info-Tage "Nano or not Nano"
CY - Online meeting
DA - 25.01.2024
KW - Pycnometry
KW - Density
KW - Nano powder
PY - 2024
AN - OPUS4-59561
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Einführung: Volume Specific Surface Area (VSSA)
N2 - Im Rahmen der 2. BAM-Akademie-Veranstaltung "Nano or not Nano" wurde die OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" vorgestellt.
Der Vortrag enthält ein Einführung zur VSSA mit Definitionen, Vorteilen und Einschränkungen.
T2 - BAM Akademie II: Info-Tage "Nano or not Nano"
CY - Online meeting
DA - 25.01.2024
KW - Nano powder
KW - VSSA
KW - Specific surface
KW - OECD TG
PY - 2024
AN - OPUS4-59560
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Herausforderungen bei der Granulometrie von (technischen) Nano-Pulvern
N2 - Einführungsvortrag im Rahmen der Veranstaltung der BAM-Akademie zur Anwendung der OECD TG 124 "Volume Specific Surface Area of Manufactured Nanomaterials" zu Herausforderungen bei der Granulometrie von Nanopulvern. Es werden die Einflüsse von Partikelform, Breite der Partikelgrößenverteilung und Agglomeration/ Aggregation auf das Messergebnis sowie die Vergleichbarkeit der Ergebnisse verschiedener Messverfahren dargelegt.
T2 - BAM Akademie II: Info-Tage "Nano or not Nano"
CY - Online meeting
DA - 25.01.2024
KW - Nanopulver
KW - Granulometrie
KW - Partikelgröße
KW - VSSA
KW - OECD TG 124
PY - 2024
AN - OPUS4-59558
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Weise, Frank
A1 - Werner, D.
A1 - Maier, Bärbel
A1 - Wilsch, Gerd
T1 - Schadenskategoriespezifische Bewertung von AKR-Prüfverfahren
T1 - Evaluation of ASR testing methods in relation to specific damage categories
N2 - Ausgehend von den verstärkt auftretenden AKR-Schäden an den vor 2005 hergestellten BAB-Abschnitten verfolgte das Forschungsvorhaben zwei Ziele. So sollte einerseits die Ursache für die mit der AKR-Schadensentwicklung einhergehende Dunkelfärbung der Oberfläche der Betonfahrbahndecke im Fugenbereich ermittelt werden. Andererseits galt es, ausgehend von der Zustands- und Schadenserfassung das AKR-Restschädigungspotenzial der Prüfkörper aus je drei ein- und zweischichtig ausgeführten, unterschiedlich stark AKR-geschädigten BAB-Abschnitten vergleichend zu bewerten. Folgende Ergebnisse wurden u. a. erzielt:
1. Dunkelfärbung Experimenteller Nachweis mit kombinierter insitu-
Feuchtemessung mit Radar (integral) und NMR (tiefenaufgelöst), dass Dunkelfärbung der Oberfläche der Betonfahrbahndecke im Fugenbereich auf eine erhöhte Durchfeuchtung der Betonrandzone zurückzuführen ist; erfolgreiche Validierung der ZfP-Ergebnisse mit Darr-Wäge-Versuch.
2. Zustand beprobter BAB-Abschnitte und schadenskategoriespezifische
Bewertung der AKR-Prüfverfahren:
• Auffinden von Horizontalrissen im Bereich der Querscheinfuge bei allen AKR-geschädigten BAB-Abschnitten,
• Ermittlung mittlerer Eindringtiefen bei Natrium von maximal 20 bis 45 mm und bei Chlorid von maximal 15 bis 60 mm im Entnahmezustand;
keine Korrelation mit der AKR-Schadenskategorie des jeweiligen BAB-Abschnitts,
• Nachweis gleichzeitig auftretender SEB bei allen AKR-geschädigten BAB-Abschnitten im Entnahmezustand,
• keine signifikante Verminderung der Spaltzugfestigkeit durch die verstärkte AKR am Plattenrand,
• Ermittlung eines erhöhten AKR-Restschädigungspotenzials bei vier der sechs beprobten BAB-Abschnitte primär mittels AKR-erformanceprüfungen,
• Ermittlung höherer Dehnungen bei Performanceprüfungen aus Ober- und Unterbeton bestehenden Halbschalen, als an separat aus Ober- und Unterbeton gewonnenen Prismen,
• Unauffälliges Verhalten nahezu aller bei der Performanceprüfung auffälligen Bestandsbetone im 40°C- und 60°C-Betonversuch; vermutete Ursache: mit LIBS nachgewiesene hohe und tiefreichende Auslaugung der Alkalien.
N2 - Our research project had two aims in addressing the increased occurrence of ASR damage on German motorway sections built before 2005: firstly, to establish the cause of the darker discolouration around the joints of concrete road surface that occurs in conjunction with ASR damage. Secondly, based on the status and damage report, it aimed to comparatively evaluate the residual ASR damage potential of test samples from three federal motorway sections of one-layer and three of twolayer pavement, showing different levels of ASR damage. We obtained the following results (among others):
1. Dark discolouration
Experimental evidence using non-destructive testing methods showing that dark discolouration of concrete road surfaces near joints is due to increased moisture in the concrete boundary zone: NDT findings successfully validated by weighing and drying test.
2. Condition of sampled motorway sections and evaluation of ASR test methods used:
• discovery of horizontal cracks located near transverse contraction joint in all motorway sections with ASR damage,
• determination of maximum mean penetration depth of sodium from 20 to 45 mm and of chloride from 15 to 60 mm in sample as extracted; no correlation with the ASR damage category of the relevant motorway
section,
• evidence of simultaneous occurrence of DEF on all ASR-damaged motorway sections in sample as extracted,
• no significant reduction of splitting tensile strength due to increased ASR at slab edge,
• increased ASR residual damage potential found on four of the six motorway sections tested primarily with ASR performance tests,
• increased expansion found during performance tests on half shells consisting of upper and lower concrete compared to prisms taken separately from upper and lower concrete,
• 40°C and 60°C concrete prism tests revealed no noticeable reactions in almost all existing concrete types that showed irregularities in
the performance test. Suggested cause: high and deep levels of alkali leaching determined by LIBS.
KW - NMR-Relaxometrie
KW - Alkali-Kieselsäure-Reaktion
KW - Betonfahrbahndecke
KW - AKR-Betonversuche
KW - Zerstörungsfreie Prüfung
KW - Radar
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:hbz:opus-bast-24661
UR - https://bast.opus.hbz-nrw.de/frontdoor/index/index/docId/2466
SN - 978-3-95606-543-9
SN - 0943-9323
VL - S 145
SP - 1
EP - 60
PB - Fachverlag NW in der Carl Ed. Schünemann KG
CY - Bremen
AN - OPUS4-54748
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Erzeugung und Charakterisierung anisotroper Nanostrukturen durch Ultrakurzpulslaser
N2 - Der Vortrag gibt einen Überblick über die Erzeugung und Charakterisierung anisotroper Nanostrukturen mittels ultrakurzgepulster Laserstrahlung. Besonderes Augenmerk liegt dabei auf dem Phänomen der sogenannten Laser-induzierten periodischen Oberflächen-Nanostrukturen auf dielektrischen Werkstoffen und ihrer zeitlichen Dynamik. Weitere Beispiele von Volumen-Nanostrukturen aus der Literatur werden diskutiert.
T2 - 21. Treffen des DGG-DKG Arbeitskreises „Glasig-kristalline Multifunktionswerkstoffe“
CY - Mainz, Germany
DA - 22.02.2024
KW - Laser-induzierte periodische Oberflächen-Nanostrukturen
KW - Quarzglas
KW - Saphir
KW - Bessel-Strahlen
PY - 2024
AN - OPUS4-59565
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - Offshore Auslagerung von nichtrostenden Stahlcoupons
N2 - Zur Erweiterung der Anwendungserfahrungen nichtrostender Stähle, insbesondere von Lean-Duplex-Stählen, unter maritimen Einsatzbedingungen, wurden Testracks auf der Umspannplattform OSS des Windparks Hohe See errichtet. Hier wurden neben Standardproben zur Korrosivitätsbestimmung nach ISO 9223 auch mehrere Serien nichtrostender Stahlgüten mit unterschiedlichen Oberflächen, Spaltausbildungen und Verarbeitungszuständen ausgelagert und nun nach 1-jähriger Bewitterungszeit bewertet. In diesem Beitrag werden Oberflächenzustände, Korrosionszustände und Lochtiefen dieser Probekörper gezeigt.
T2 - 21. Tagung Korrosionsschutz in der maritimen Technik
CY - Hamburg, Germany
DA - 24.01.2024
KW - Korrosion
KW - Offshore
KW - Atmosphärische Korrosion
KW - Nichtrostender Stahl
KW - Edelstahl rostfrei
PY - 2024
AN - OPUS4-59452
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - Demonstrationsexperimente
N2 - Ergänzend zu den theoretischen Betrachtungen des Korrosionsverhaltens nichtrostender Stähle werden in diesem Vortrag Demonstrationsexperimente gezeigt.
T2 - Seminar Korrosionsverhalten nichtrostender Stähle in wässrigen Medien und bei atmosphärischer Beanspruchung
CY - Düsseldorf, Germany
DA - 30.01.2024
KW - Korrosion
KW - Experimente
KW - Elektrochemie
KW - Nichtrostender Stahl
KW - Edelstahl rostfrei
PY - 2024
AN - OPUS4-59455
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Ellipsometry as a tool for electrical metrology - Referencing electrical properties of thin layers with TCO materials
N2 - Ellipsometry is a highly valuable technology for bridging different measurement methods. As a fast, highly sensitive, and non-destructive optical technique with low environmental requirements, it is ideal for transporting measurement accuracy and for up-scaling measurements in the production environment. It can be used for highly precise determination of properties, material identity and correctness confirmation, as well as defect detection.
Comparable, traceable, and accurate electrical measurements, especially at small scales are one of the biggest challenges in the development of the electrical and electronic devices of the future.
In this project, we develop structured thin layer systems of the transparent conductive material indium tin oxide (ITO) to prove the concept of using these systems as standards for conductivity and permittivity. The layers are produced in a reactive magnetron sputtering process from raw ITO targets with additional oxidation achieved by oxygen injection. We present results of a study correlating the coating process conditions with the properties of the final layer material. We found that especially the temperature development during coating is of key importance and determines the layer properties to a large extent. We will discuss questions of homogeneity and reproducibility of the coating processes used. The finished layers undergo lithographic structuring and etching to produce patterns to serve as reference structures for scanning probe electrical measurements. TCOs have a large variety of applications. In this work we also study the usability of ITO for other purposes and investigate the stability of this material under application conditions.
T2 - 12th Workshop Ellipsometry 2023
CY - Prague, Czech Republic
DA - 18.09.2023
KW - Thin Films
KW - Transparent Conductive Oxides
KW - Ellipsometry
KW - Electrical Properties
KW - Nanoelectronics
PY - 2023
AN - OPUS4-58410
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Grabowski, Sven
A1 - Sahrhage, H.
A1 - Lampke, T.
T1 - Electrochemical corrosion investigations on binary and ternary zinc alloy coatings using gel electrolytes
N2 - Novel agar-based test electrolytes are used to perform electrochemical corrosion investigations on ZnFe and ZnNi binary as well as ZnFeMo ternary zinc coatings. The objectives of the electrochemical investigations include the characterization of the corrosion behavior, the description of the protective effect of the coatings as well as the investigation of the layer formation and degradation under artificial aging. ZnFe and ZnFeMo coatings are applied with varying iron content as well as an additional passivation layer, respectively, to study the effect on corrosion resistance. The results show that the protective effect of the coatings is not negatively influenced by different iron contents or the addition of molybdenum. Additional passivation of the ZnFe-containing coatings by means of a passivating agent leads to a significant improvement in the protective effect. Artificial aging leads to slight degradation of the additional passivation layer whereas coatings without post-treatment enhance their protective effect by the formation of corrosion product layers.
KW - Binary zinc alloys
KW - Ternary zinc alloys
KW - Corrosion testing
KW - Gel electrolytes
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543013
DO - https://doi.org/10.1002/adem.202101336
SN - 1438-1656
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Advances in ultrafast laser manufacturing: nanostructures, thin films, and scaling perspectives
N2 - Advanced ultrafast laser technology is a rapidly growing field that currently enables many new industrial and scientific applications. During the last decades, this has been significantly driven by the availability of high-repetition-rate laser sources and novel beam delivery concepts. At the laser side, Moore’s law equally manifests for ultrafast laser technologies, since the average output power of such lasers doubles approximately every two years. This development is mainly driven by the increase of the pulse repetition rates of energetic laser pulses, currently enforcing the development of smart beam control and novel scanning strategies for preventing heat-accumulation and plasma-shielding effects during laser-based materials processing. This keynote presentation addresses the advantages, recent developments, and perspectives of laser processing with ultrashort laser pulses. A special focus is laid on the tailored structuring of thin films as well as the manufacturing and probing of sub-diffraction surface nanostructures – an ongoing race to extreme scales. Current limitations are identified and an outlook to future scaling perspectives will be provided.
T2 - SPIE Photonics Europe 2024 Conference, Symposium "Lasers and Photonics for Advanced Manufacturing"
CY - Strasbourg, France
DA - 07.04.2024
KW - Ultrafast laser processing
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Laser technology
KW - Time-resolved analysis
PY - 2024
UR - https://spie.org/photonics-europe/presentation/Advances-in-ultrafast-laser-manufacturing--nanostructures-thin-films-and/13005-36#_=_
AN - OPUS4-59852
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Korrosionsarten bei nichtrostenden Stählen
N2 - Übersichtsvortrag zu Korrosionsarten, die bei nichtrostenden Stählen unter verschiedenen Einsatzbedingungen auftreten können. Die Grundlagen zur Pasivität und der örtlichen Störung der Passivität werden im Zusammenspiel komplexer Einflussfaktoren des Korrosionssystems herausgestellt. Die erarbeiteten theoretischen Grundlagen werden anhand praktischer Beispiel für alle relevanten Korrosionsarten vertieft.
T2 - VDEh Seminar "Korrosionsverhalten nichtrostender Stähle in wässrigen Medien und bei atmosphärischer Beanspruchung*
CY - Düsseldorf, Germany
DA - 30.01.2024
KW - nichtrostender Stahl
KW - Korrosionsverhalten
KW - Passivität
PY - 2024
AN - OPUS4-59549
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - The Dark Side of Science (2024 edition)
N2 - This presentation highlights ongoing scientific misconduct as found in academic literature. This includes data- and image manipulation, and paper mills. Starting with an expose of examples, it delves deeper into the causes and metrics driving this phenomenon. Finally a range of possible tools is presented, that the young researcher can use to prevent themselves from sliding into the dark scientific methods.
T2 - Winter School on Metrology and Nanomaterials for Clean Energy
CY - Claviere, Italy
DA - 28.01.2024
KW - Scientific misconduct
KW - Data manipulation
KW - Image manipulation
KW - Paper mills
KW - Causes leading to scientific misconduct
KW - Tools to combat scientific misconduct
KW - Metrics
PY - 2024
AN - OPUS4-59622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Glimpses of the future: Systematic investigations of 1200 mofs using a highly automated, full-stack materials research laboratory
N2 - By automatically recording as much information as possible in automated laboratory setups, reproducibility and traceability of experiments are vastly improved. This presentation shows what such an approach means for the quality of experiments in an X-ray scattering laboratory and an automated synthesis set-up.
T2 - Winter School on Metrology and Nanomaterials for Clean Energy
CY - Claviere, Italy
DA - 28.01.2024
KW - Digitalization
KW - Automation
KW - Digital laboratory
KW - Scattering
KW - Synthesis
KW - Nanomaterials
KW - Holistic science
PY - 2024
AN - OPUS4-59621
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Simon, P.
ED - Ihlemann, J.
ED - Bonse, Jörn
T1 - Laser-generated periodic nanostructures
N2 - This book is a reprint collection of articles from the Special Issue published online in the open access journal Nanomaterials.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Direct laser-interference patterning (DLIP)
KW - Applications
KW - Numerical simulations
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535146
UR - https://www.mdpi.com/books/pdfview/book/4426
SN - 978-3-0365-2027-8
SN - 978-3-0365-2028-5
DO - https://doi.org/10.3390/books978-3-0365-2028-5
SP - 1
EP - 328
PB - MDPI
CY - Basel
AN - OPUS4-53514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Weise, Frank
A1 - Oesch, T.
A1 - Wilsch, Gerd
A1 - Sigmund, S.
A1 - Hünger, K.-J.
A1 - Kositz, M.
T1 - Analyse des gefügeabhängigen Löslichkeitsverhaltens potenziell AKR-empfindlicher Gesteinskörnungen
T1 - Analysis of the microstructure depending solubility behavior of potential ASR sensitive aggregates
N2 - Das gefügeabhängige Löslichkeitsverhalten wurde an folgenden vier Gesteinskörnungen unterschiedlicher Alkaliempfindlichkeitsklassen
untersucht:
• GK1 (EIII-S): quarzreicher Kies
• GK2 (EIII-S): Grauwacke (Splitt)
• GK3 (EI-S): Quarz-Feldspat-Porphyr (Splitt)
• GK4 (EI-S): sandsteinreicher Kies
DiePorenstrukturanalyse erfolgte sowohl an Einzelkörnern mittels vergleichender 3D-CT und BET- Untersuchungen als auch an Korngemengen der einzelnen Kornfraktionen (außer Fraktion 16/22 mm) über die Wasseraufnahme und mit BET. Für die Visualisierung und Quantifizierung der von außen zugänglichen Oberflächenanteile der Einzelkörner wurde ein Softwaretool entwickelt, erprobt und erfolgreich angewandt. Es gelang so u.a. den Nachweis zu erbringen, dass die gebrochenen Einzelkörner der Grauwacke und des Rhyoliths einen deutlich geringeren von außen zugänglichen Oberflächenanteil als die gleichartigen Gesteinskörner aus dem Kies besitzen. Aufgrund der limitierten Ortsauflösung der 3D-CT von 11 bis 16,5 μm wurde mit BET eine um drei Zehnerpotenzen höhere spezifische Oberfläche ermittelt.
Zu den Porositätsuntersuchungen an den Korngemengen sei angemerkt, dass zum Teil gegenläufige Trends zwischen offener Porosität und spezifischer Oberfläche festgestellt wurden. Dieses ist beim Bezug des bei den Löseversuchen in 0,1 M KOH mit definierter NaCl-Zugabe aus der Gesteinskörnung gelösten SiO2 und Al2O3 von zentraler Bedeutung. Bei den Löseversuchen an den fraktionsspezifischen Korngemengen selbst zeigte sich, dass die stufenweise Erhöhung des NaCl-Gehalts von 0 auf 10 M.-% im Eluat eine erhöhte SiO2-Löslichkeit und eine verminderte Auslaugung von Al2O3 zur Folge hat. Auffallend war hierbei, dass die Al2O3-Löslichkeit bei GK4 ohne und mit geringer NaCl-Zugabe die mit Abstand höchsten Werte annimmt. Bei den zusätzlich durchgeführten Löseversuchen an den tomografierten Einzelkörnern in 1 M KOH-Lösung mit Zugabe von 1 M.-% NaCl zeigte sich, dass nur vereinzelt bei den untersuchten Gesteinsarten eine Korrelation zwischen dem SiO2- bzw. Al2O3-Gehalt im Eluat und der absoluten BET-Oberfläche nachweisbar ist. Dies ist vermutlich darauf zurückzuführen, dass neben der Oberfläche weitere Parameter (z.B. die mineralogische Zusammensetzung der Einzelkörner) das Löseverhalten maßgebend beeinflussen. Bei den parallel zu den Löseversuchen durchgeführten Betonversuchen nach dem ARS 04/2013 zeigte sich, dass die Alkaliempfindlichkeit der GK4 bei beiden Betonversuchen mit Alkalizufuhr unterschiedlich zu bewerten ist. So ist unabhängig von der vorgegebenen pessimalen Betonrezeptur des Fahrbahndeckenbetons ausschließlich bei der Klimawechsellagerung die GK4 als alkaliempfindlich einzustufen. Allerdings konnte der Befund der stark ausgeprägten AKR bei der GK4 mit der Dünnschliffmikroskopie nicht bestätigt werden. Analoges gilt für die Bewertung der Alkaliempfindlichkeit von GK2 mit den Betonversuchen nach der Alkalirichtlichtlinie des DAfStb. So ist auch hier die GK2 nicht im 60 °C-Betonversuch sondern ausschließlich im 40 °C-Betonversuch als alkaliempfindlich einzustufen.
Dienach den verschiedenartigen Betonversuchen durchgeführten LIBS-Analysen am Vertikalschnitt der Prüfkörper zeigen, dass im Kernbereich nach dem 60 °C-Betonversuch mit 10 %iger NaCl-Lösung und nach der Klimawechsellagerung mit NaCl-Beaufschlagung annähernd gleich hohe Natrium- und Chloridgehalte vorgefunden werden. Wider Erwarten treten an den beaufschlagten Prüfflächen Abreicherungen von Natrium und Anreicherungen von Chlorid auf. Im 40°C- und 60 °C-Betonversuch wurde das Natrium bis in eine maximale Tiefe von ca. 30 mm bzw. 20 mm ausgelaugt. Die aufbauenden korrelativen Betrachtungen zwischen den Ergebnissen des 60°C Betonversuchs mit Alkalizufuhr und der Löseversuche an den fraktionsspezifischen Korngemengen in 1 M KOH-Lösung mit definierter NaCl-Zugabe sind durchaus vielversprechend. So zeigt sich beispielsweise beim Waschbeton, dass der fraktionsspezifisch gewichtete SiO2-Überschuss im Eluat nach 56 Tagen mit Zugabe von 0,5 M.-% NaCl ohne Bezug auf die BET-Oberfläche zur gleichen Einstufung der vier betrachteten Gesteinskörnungen wie bei den Dehnungen im 60 °C-Betonversuch mit 3 %-iger NaCl-Lösung führt. Außerdem korrelieren die im 60 °C-Betonversuch mit 10 %-iger NaCl-Lösung ermittelten Dehnungen mit dem gewichteten SiO2-Überschuss im Eluat bei Zugabe von 2 M.-% NaCl ohne Bezug auf die BET-Oberfläche.
Ausschließlich bei den Betonversuchen nach der Alkali-Richtlinie erwies sich der Bezug des im Eluat ermittelten SiO2-Überschusses auf die BET-Oberfläche als zielführend. Aufgrund des Potenzials der Löseversuche mit NaCl-Zugabe für die Bewertung der Alkaliempfindlichkeit der Gesteinskörnung im Fahrbahndeckenbeton wird empfohlen, die vergleichenden Untersuchungen zwischen den Löseversuchen an Korngemischen der einzelnen Fraktionen und den Betonversuchen nach dem ARS 04/2013 mit einer möglichst hohen Anzahl an Gesteinskörnungen und einem präzisierten Untersuchungsumfang fortzuführen.
N2 - The following four aggregates (GK) of varying grades of alkali sensitivity were examined for their microstructure-dependent solubility behavior:
• GK1 (EIII-S) gravel with high quarz content
• GK2 (EIII-S) greywacke (crushed stone)
• GK3 (EI-S) quarz-feldspar-porphyry (crushed stone)
• GK4 (EI-S) gravel with high sandstone content
Pore structure analysis was carried out both on single grains using comparative 3D-CT and BET tests, and on grain samples of individual grain fractions (excluding the 16/22 mm fraction) using water absorption and BET. A software tool for visualizing and quantifying the externally accessible surfaces of single grains was developed, tested and successfully applied.
This enabled us, among other things, to prove that single broken grains of greywacke and rhyolite have a much smaller externally accessible surface than grains of gravel of the same aggregate fraction. Due to the 3D-CT’s limited spatial resolution of 11 to 16.5 μm, BET was used to determine a two to three powers of ten higher specific surface.
In relation to the porosity tests of the grain samples, it should be noted that in some cases, counterdirectional trends between open porosity and specific surface were determined. This is of central importance in relation to the SiO2 and Al2O3 dissolved from the aggregate in the solubility tests in 1 M KOH with defined addition of NaCl.
The solubility tests on the grain samples of specific fractions showed that the gradual increase of the NaCl content in the eluate from 0 to 10 M.-% resulted in increased SiO2 solubility and reduced leaching of Al2O3. It was striking in this context that the solubility of Al2O3 in GK4 with no or little addition of NaCl gives by far the highest values.
The additional solubility tests carried out on single grains, that were previously subjected to CT testing, in 1 M KOH solution with 1 M.-% added NaCl showed that in the types of aggregate examined, a correlation between the SiO2 and Al2O3 in eluate and the absolute BET surface is only occasionally demonstrable. This is probably due to the fact that solubility behavior is decisively influenced by other parameters in addition to the surface (e.g. by the mineralogical composition of individual grains).
The concrete tests according to ARS 04/2013 carried out parallel to the solubility tests showed that GK4’s alkali sensitivity in both concrete tests with added alkali must be evaluated differently.
For example, independent of the prescribed pessimal road surface concrete formula, GK4 can only be classified as alkali sensitive under cyclic storage. However petrographic microscopy could not confirm the findings of very marked ASR in GK4. The same applies to the evaluation of alkali sensitivity in GK2 with the concrete tests according to the German Committee for Structural Concrete (DAfStb)’s Alkali Guidelines. In this case too, GK2 should not be classified as alkali sensitive in 60 °C concrete testing, but only in 40 °C concrete testing.
The LIBS analyses carried out on the vertical cross-section of the test specimens after the various concrete tests showed that almost equally high sodium and chloride levels were found in the core area after the 60 °C concrete prism test with 10 % NaCl solution and after cyclic storage with NaCl application. Contrary to expectations, the surfaces of samples after NaCl application showed a decrease in sodium and an increase in chloride. In the 40°C and 60°C concrete prism tests, sodium was depleted up to a maximum depth of approx. 30 mm and 20 mm respectively.
Subsequent correlative observations between the findings of the 60°C concrete prism test with alkali application, and the solubility tests on the samples of specific grain fractions in 1 M KOH solution with defined NaCl addition, are very promising. In the case of exposed aggregate concrete, for example, the fraction-specific weighted excess SiO2 to in the eluate after 56 days with added 0.5 M.-% NaCl unrelated to the BET surface results in the same classification of the four aggregates examined as the expansions in the 60 °C concrete prism test with 3% NaCl solution. In addition, the expansions found in the 60 °C concrete prism test with 10% NaCl solution correlated with the weighted excess SiO2 in eluate with added 2 M.-% NaCl without relation to the BET surface. Only in the case of the concrete test in accordance with the Alkali Guidelines did the relationship of the excess SiO2 in the eluate to the BET surface prove to be productive.
Due to the potential of the solubility test with added NaCl for the evaluation of alkali sensitivity of aggregates in road surface concrete, we recommend continuing with comparative tests between solubility tests of grain samples of the various fractions and the concrete tests in accordance with ARS O4/13 with the greatest possible number of aggregates and a precisely defined investigation scope.
KW - LIBS
KW - Betonfahrbahndecke
KW - Alkali-Kieselsäure-Reaktion
KW - Gesteinskörnung
KW - Alkaliempfindlichkeit
KW - 3D-CT
KW - Tausalzeintrag
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:hbz:opus-bast-25832
UR - https://bast.opus.hbz-nrw.de/frontdoor/index/index/docId/2583
SN - 978-3-95606-648-1
SN - 0943-9323
VL - S 165
SP - 1
EP - 111
PB - Fachverlag NW in der Carl Ed. Schünemann KG
CY - Bremen
AN - OPUS4-54755
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weise, Frank
A1 - von Werder, Julia
A1 - Manninger, Tanja
A1 - Maier, Bärbel
A1 - Fladt, Matthias
A1 - Simon, Sebastian
A1 - Gardei, Andre
A1 - Höhnel, Desirée
A1 - Pirskawetz, Stephan
A1 - Meng, Birgit
T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction
N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide.
The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented.
KW - Mitigation strategies
KW - Concrete
KW - Damage analysis
KW - Alkali silica reaction
KW - Road pavement
KW - Accelerated testing
KW - Non-destructive testing
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:101:1-2022052515100075090235
DO - https://doi.org/10.1002/adem.202101346
SN - 1527-2648
VL - 24
IS - 6
SP - 1
EP - 36
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Funktionalisierung durch laser-induzierte periodische Oberflächenstrukturen
N2 - Der Vortrag gibt einen Überblick über die vielfältigen Möglichkeiten der Oberflächenfunktionalisierung mittels Mikro- und Nanostrukturierung durch Ultrakurzpuls-Lasermaterialbeabeitung. Dies schließt eine Diskussion des Phänomens der Laser-induzierten periodischen Oberflächenstrukturen (LIPSS, engl.: Laser-induced Periodic Surface Structures, Ripples), sowie deren Klassifikation und Bildungsmechanismen mit ein. Ein Schwerpunkt der Präsentation liegt auf der Diskussion verschiedener Anwendungsmöglichkeiten der LIPSS in Bereichen der Optik, Fluidik, Tribologie und Medizin, sowie auf einem Ausblick auf die industrielle Skalierbarkeit der LIPSS-Technologie.
T2 - 1. Netzwerktreffen 2024 des UKPL-Innovationsnetzwerks
CY - Rostock, Germany
DA - 11.03.2024
KW - Laser-induced Periodic Surface Structures (LIPSS)
KW - Oberflächenfunktionalisierung
KW - Mikrostrukturen
KW - Nanostrukturen
KW - Ultrakurzpuls-Laserbearbeitung
PY - 2024
AN - OPUS4-59657
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lozano Duarte, Daniel Hernando
T1 - Modeling guided waves interacting with arbitrarily shaped inhomogeneities using SBFEM in combination with an extruded quadtree decomposition for 3D plates
N2 - For structural health monitoring systems or non-destructive testing, it is crucial to study the interactions of ultrasonic-guided waves with inhomogeneities or damage in structural components. Simulation of these interactions poses a challenge.
After the wave-damage interaction, the numerical model must reproduce features like mode conversion or wave scattering. Mathematically, damages are discontinuities in a computational domain, and each interacts diversely depending on its geometrical features. We propose a quadtree-based meshing in the current contribution to capture these geometrical
characteristics.
This kind of discretisation approach requires special techniques to couple cells of different sizes since, after a quadtree decomposition, the problem of so-called hanging nodes may arise. Transition elements based on high-order transfinite shape functions are used to solve this issue. The advantage is that these elements allow the correct coupling of the cells while retaining a high-order interpolation. Moreover, the reuse of the dynamic stiffness matrices can be exploited based on the similarity of the cells. This procedure renders the approach very efficient.
Examples show the scattering characteristics of different guided wave modes after interacting with inhomogeneities and discontinuities in a plate.
T2 - DAGA 2023
CY - Hamburg, Germany
DA - 06.03.2023
KW - SBFEM
KW - Quadtree
KW - Image-based models
KW - Wave-defect interaction
PY - 2023
AN - OPUS4-59661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lozano Duarte, Daniel Hernando
T1 - Octree Meshes for Ultrasonic Guided Waves: Mortar coupling combined with the Scaled Boundary Finite Element Method in Prismatic Structures
N2 - Ultrasonic guided waves interacting with complex geometrical features are of high interest in the SHM field. For example, investigations into the extent to which a small change in defect geometry affects wave propagation have applications in Probability of Detection and defect reconstruction. These fields have to be supported by numerical tools aiming to retrieve accurate and reliable results and, thus, more realistic modeling.
Due to the short wavelengths of ultrasonic waves and the relatively large domains in which the waves propagate, fine grid resolution for the entire domain is usually not possible due to limited computational resources. One solution is to partition the domain into different subdomains and use a specific, efficient approach for each subdomain.
This contribution shows a combination of methods that aims to study these wave defect interactions in an elastic media. Firstly we introduce high-order 3D meshes that can resolve very fine geometrical details and are based on an Octree discretisation technique that employs special transition shape functions to resolve the hanging nodes that may appear due to the nature of the method. Afterward, the Octree mesh is embedded in a prismatic wave-guide based on the semi-analytical formulation of the SBFEM in 3D. To couple the different domains, we employ the mortar method, which enforces the continuity of the wave field across the internal boundaries of the domains. Examples show the power of the approach especially when it comes to parametric analysis.
T2 - YIC23
CY - Porto, Portugal
DA - 19.06.2023
KW - Octrees
KW - Sbfem
KW - Ultrasound
KW - Mortar method
PY - 2023
AN - OPUS4-59662
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 52, Heft 3
T3 - Amts- und Mitteilungsblatt der BAM - 3/2022
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558323
SN - 0340-7551
VL - 52
IS - 3
SP - 159
EP - 404
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-55832
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lüdicke, M. G.
A1 - Hildebrandt, Jana
A1 - Schindler, C.
A1 - Sperling, R. A.
A1 - Maskos, M.
T1 - Automated QuantumDots Purification via Solid Phase Extraction
N2 - The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, resulting in an efficient scalable process in regard to time and solvent consumption, using common laboratory equipment and low-cost materials. The procedure is based on a combination of solvent-induced adhesion and solid phase extraction. The platform allows the transition from manual handling towards automation, yielding an overall purification performance similar to one conventional batch precipitation/centrifugation step, which was investigated by thermogravimetry and gas chromatography. The distinct miscibility gaps between surfactants used as nanoparticle capping agents, original and extraction medium are clarified by their phase diagrams, which confirmed the outcome of the flow chemistry process. Furthermore, the solubility behavior of the Quantum Dots is put into context with the Hansen solubility parameters framework to reasonably decide upon appropriate solvent types.
KW - Quantum Dots
KW - Purification
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559590
DO - https://doi.org/10.3390/nano12121983
SN - 2079-4991
VL - 12
IS - 12
PB - MDPI
CY - Basel
AN - OPUS4-55959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yusenko, Kirill
T1 - Reaction of high-entropy alloys with hydrogen under extreme conditions
N2 - In the current study, we investigate an interaction under high-pressure high-temperature of single phase fcc-, hcp- and bcc-structured high-entropy alloys with hydrogen, carbon and nitrogen to obtain high-entropy hydrides, carbides and nitrides. Structural changes in high-entropy alloys upon compression and heating in the presence of these light elements are in the focus of our investigation. An easy route to high-entropy hydrides, carbides and nitrides will open new synthetic horizons in compositionally complex materials. Our study suggests that high-entropy alloys form high- entropy hydrides mainly with a composition close to M:H 1:1 ratio. Hydrides can be obtained under compression with hydrogen as a pressure compression medium or using hydrogen fluid as reactive agent.
T2 - Intermetallics 2023
CY - Bad Staffelstein, Germany
DA - 03.10.2023
KW - HEA
PY - 2023
AN - OPUS4-58555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lifka, S.
A1 - Harsányi, K.
A1 - Baumgartner, E.
A1 - Pichler, L.
A1 - Baiko, D.
A1 - Wasmuth, Karsten
A1 - Heitz, J.
A1 - Meyer, M.
A1 - Joel, A.-C.
A1 - Bonse, Jörn
A1 - Baumgartner, W.
ED - Mail, M.
T1 - Laser-processed antiadhesive bionic combs for handling nanofibers inspired by nanostructures on the legs of cribellate spiders
N2 - Nanofibers are drawing the attention of engineers and scientists because their large surface-to-volume ratio is favorable for applications in medicine, filter technology, textile industry, lithium-air batteries, and optical sensors. However, when transferring nanofibers to a technical product in the form of a random network of fibers, referred to as nonwoven fabric, the stickiness of the freshly produced and thus fragile nanofiber nonwoven remains a problem. This is mainly because nanofibers strongly adhere to any surface because of van der Waals forces. In nature, there are animals that are actually able to efficiently produce, process, and handle nanofibers, namely cribellate spiders. For that, the spiders use the calamistrum, a comb-like structure of modified setae on the metatarsus of the hindmost (fourth) legs, to which the 10–30 nm thick silk nanofibers do not stick due to a special fingerprint-like surface nanostructure. In this work, we present a theoretical model of the interaction of linear nanofibers with a sinusoidally corrugated surface. This model allows for a prediction of the adhesive interaction and, thus, the design of a suitable surface structure to prevent sticking of an artificially nonwoven of nanofibers. According to the theoretical prediction, a technical analogon of the nanoripples was produced by ultrashort pulse laser processing on different technically relevant metal surfaces in the form of so-called laser-induced periodic surface structures (LIPSS). Subsequently, by means of a newly established peel-off test, the adhesion of an electrospun polyamide fiber-based nonwoven was quantified on such LIPSS-covered aluminium alloy, steel, and titanium alloy samples, as well as on polished (flat) control samples as reference and, additionally, on samples with randomly rough surfaces. The latter revealed that the adhesion of electrospun nanofiber nonwoven is significantly lowered on the nanostructured surfaces compared with the polished surfaces.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Cribellate spiders
KW - Calamistrum
KW - Electrospinning
KW - Nanofibers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561799
DO - https://doi.org/10.3762/bjnano.13.105
SN - 2190-4286
VL - 13
SP - 1268
EP - 1283
PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften
CY - Frankfurt, M.
AN - OPUS4-56179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, Sven
A1 - Jaenisch, Gerd-Rüdiger
A1 - Pavasaryte, Lina
A1 - Funk, Alexander
T1 - XCT and DLW: Synergies of Two Techniques at Sub-Micrometer Resolution
N2 - Direct Laser Writing (DLW) and X-ray computed tomography (XCT) both offer unique possibilities in their respective fields. DLW produces full three-dimensional (3D) polymer structures on the microscale with resolutions below 100 nm. The fabricated structures can be analysed by XCT or X-ray microscopy (XRM), which incorporates additional X-ray lenses, in three dimensions down to a minimal basic spatial resolution of about 500 nm or 50 nm, respectively. In this work, two different DLW structures are analysed via XCT. Internal defects are detected and analysed for the purpose of quality control. Defects and structures with sizes down to 1.5 µm are successfully analysed. A 3D reconstruction and internal, hidden features of the fabricated structures are shown and discussed. In a first-of-its-kind study, we demonstrate the detectability of a single-voxel line inside a fabricated structure that would not be detectable with SEM or light microscopy. Furthermore, the direct fabrication on a PET substrate is shown to overcome the high X-ray absorbance of commonly used glass substrates. Attenuation spectra of SZ2080 and glass substrates are compared to a fabrication route direct on a 170 µm PET foil. The practical aspects of XCT measurements for DLW structures on different substrates will be discussed.
KW - Non-destructive testing
KW - Two-photon polymerization
KW - X-ray microscopy
KW - XCT
KW - 2PP
KW - Direct laser writing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560525
DO - https://doi.org/10.3390/app122010488
VL - 12
IS - 20
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-56052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Lehmann, Jens
A1 - Burkert, Andreas
T1 - Field exposure study under sheltered and open exposure conditions at different test sites in Germany: First‐year corrosion rate and atmospheric corrosivity
N2 - The corrosivity of atmospheres in Europe has changed significantly in recent decades. For the Federal Republic of Germany, no current values for the corrosion rate based on 1‐year atmospheric exposure of standard specimens can be found in the scientific literature after 2000. This paper presents results from a field exposure study in the Berlin metropolitan area and Helgoland in 2016. Based on standard specimens, values for the corrosion rate and the corresponding atmospheric corrosivity category are determined for open exposure and indirect weathering in a ventilated enclosure as sheltering after 1 year of exposure. The results prove that determined corrosivity categories are material‐specific. Sheltered exposure is a typical atmospheric situation for many building components. It allows statements on the effect of the concentration of airborne substances on the corrosivity beyond the normative requirements.
KW - Atmospheric corrosion
KW - Corrosivity category
KW - ISO 9223
KW - Mass loss
KW - Atmosphärische Korrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565099
DO - https://doi.org/10.1002/maco.202213582
SN - 0947-5117 (print)
SN - 1521-4176 (online)
SP - 1
EP - 15
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-56509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - Structuring of thin films by ultrashort laser pulses
N2 - Modern life and global communication would not be possible without technologically tailored thin films; they are omnipresent in daily life applications. In most cases, the films are deposited entirely at the carrying substrates in a specific processing step of the device or sample. In some cases, however, removal or modification must be performed locally, i.e., site-controlled and material selective through an additional laser processing step. For that ultrashort laser pulses with durations in the femtosecond and picosecond range can provide unique advantages and capabilities in industrially scalable schemes. This article reviews the current state of the research and corresponding industrial transfer related to the structuring of thin films by ultrashort pulsed lasers. It focuses on the pertinent historic developments, reveals the relevant physical and chemical effects, explores the ultimate limits, and discusses selected industrial and scientific applications.
KW - Thin films
KW - Laser processing
KW - Ultrashort lasers
KW - Laser damage
KW - Femtosecond laser ablation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565732
DO - https://doi.org/10.1007/s00339-022-06229-x
SN - 0947-8396
SN - 1432-0630
VL - 129
IS - 1
SP - 1
EP - 38
PB - Springer
CY - Berlin
AN - OPUS4-56573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - OECD Prüfrichtlinie 125
N2 - Diese Präsentation ist eine Einführung in die OECD TG 125 zur Bestimmung der Partikelgrößen von Nanomaterialien. Es wird auf die verchiedenen Probleme der Partikelgrößenbestimmung eingegangen wie z.B. verschiedene Oberflächenschichten, Äquivalenzdurchmesser und Verteilungsfunktionen. Gleichzeitig werden die neuen Begrifflichkeiten eingeführt, die in der TG 125 definiert neu werden.
T2 - BAM Akademie Digitaler Info-Tag "Nano or not Nano"
CY - Online meeting
DA - 16.02.2023
KW - Nano
KW - Partikel
KW - Größe
KW - Partikeldurchmesser
KW - Äquivalenzdurchmesser
PY - 2023
AN - OPUS4-58449
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Differentielles Mobilitäts Analyse System (DMAS)
N2 - Die Bestimmung der Nanopartikelgrößen- und -formverteilung nach OECD TG 125 mit einem Differentiellen Mobilitäts Analyse System (DMAS), auch bekannt als SMPS, wird vorgestellt:
- Generelles Messprinzip
- Welchen Durchmesser misst die Methode?
- Welche Partikel kann diese Methode messen?
- Welche Informationen kann diese Methode liefern?
- Wo stößt die Methode an ihre Grenzen?
- Implementierung und Datenauswertung,
- Reporting.
Anschließend wurde eine Q&A-Session für DMAS/SMPS organisiert.
T2 - BAM Akademie Digitaler Info-Tag "Nano or not Nano"
CY - Online meeting
DA - 16.02.2023
KW - Partikel
KW - Nanopartikel
KW - SMPS
KW - Größenbestimmung
KW - DMAS
PY - 2023
AN - OPUS4-58450
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costache, F.
A1 - Valette, S.
A1 - Bonse, Jörn
T1 - Editorial: Special Issue “Dynamics and Processes at Laser-Irradiated Surfaces—A Themed Issue in Honor of the 70th Birthday of Professor Jürgen Reif”
N2 - The Special Issue “Dynamics and Processes at Laser-irradiated Surfaces” is dedicated to the 70th birthday of Jürgen Reif, retired full professor, former Chair of Experimental Physics II of the Faculty of Physics of the Brandenburg University of Technology Cottbus—Senftenberg in Germany.
KW - Laser ablation
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Femtosecond laser
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569482
DO - https://doi.org/10.3390/nano13030611
SN - 2079-4991
VL - 13
IS - 3
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-56948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cappella, Brunero
A1 - Spaltmann, Dirk
A1 - Gee, M.
T1 - Editorial: Tribology and Atomic Force Microscopy - Towards Single Asperity Contact
N2 - The concept behind this Research Topic (RT) was to collect works, in which Atomic Force Microscopy (AFM) techniques are employed to study tribological phenomena and to push the resolution of measurements towards single asperity contact. Thanks to the direct determination of sample height with sub-nanometer resolution and the possibility of measuring local friction, AFM can be employed after a tribotest to detect topography and friction changes at the nanometer scale. Recently, efforts are being expended to use AFM cantilevers as tribometers, i.e., as probes altering the volume of suitable samples, thereby measuring tip and/or sample wear and friction at the nano/microscale. Thus, single asperity contact, friction, and wear can be investigated. Since friction and wear at the macroscale are the result of asperities interactions, such experiments are of great importance for better understanding of tribological processes.
KW - Nanotribology
KW - Friction
KW - Wear
KW - Single asperity
KW - AFM
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571037
DO - https://doi.org/10.3389/fmech.2022.853934
SN - 2297-3079
VL - 8
SP - 1
EP - 2
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-57103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Einfluss der Oberflächennachbearbeitung auf die Korrosionsbeständigkeit von Schweißnähten
N2 - Bedingung für den schadensfreien Einsatz nichtrostender Stähle ist die vollständige Ausbildung der Passivschicht. Voraussetzung dafür sind glatte, blanke, saubere Oberfläche, eine gleichmäßige Elementverteilung, wenig Ausscheidungen und Verunreinigungen. Eine mögliche Beeinflussung der Gefügeausbildung durch Warmumformung und durch die schweißtechnische Verarbeitung sind zu beachten. Anlauffarben müssen durch geeignete geeignete chemische bzw. mechanische Nachbehandlung entfernt werden. Eine ausreichende Nachbehandlung kann durch elektrochemische Prüfverfahren ebenso sichergestellt werden wie mittels der KorroPad-Prüfmethode. Letzte ist einfach und schnell in der Anwendung und ermöglicht es dem Verarbeiter, die Geeignetheit einer Nachbehandlung zu überprüfen.
T2 - Fachtagung Edelstahl Rostfrei
CY - Dresden, Germany
DA - 19.10.2023
KW - Nichtrostender Stahl
KW - Korrosionsverhalten
KW - Schweißnaht
KW - Nachbearbeitung
KW - KorroPad Prüfverfahren
PY - 2023
AN - OPUS4-58703
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Swaminathan, Srinivasan
A1 - Kumar, S.
A1 - Kranzmann, Axel
A1 - Hesse, Rene
A1 - Goldbeck, Hennig
A1 - Fantin, Andrea
T1 - Corrosion characteristics of 316L stainless steel in oxide-rich molten solar salt at 600◦C
N2 - An attempt has been made in this work, to observe the influence on alloy aging by the sodium oxide (Na2O) in solar salt (60 wt% NaNO3 + 40 wt% KNO3). The accelerated aging was established by adding Na2O (0.005, 0.07, 0.135 and 0.2 wt%) to the solar salt and their effect on corrosion of 316L stainless steel (SS) at 600 ◦C in that oxide-rich solar salts for 168 h in synthetic air was investigated. Corrosion is significantly more in oxide-rich solar salt compared to pure solar salt. Strikingly, the oxide scale-base metal interface is wavy in solar salt containing 0.005 % Na2O clearly shows the oxide addition to salt melt influences Cr-rich inner oxide layer formation and its selective dissolution at early stage that leads to non-uniform corrosion. Interestingly, with increase of Na2O to 0.07 %, steel corrosion proceeded uniformly by accelerated disintegration of Cr-rich inner layer and subsequent dissolution. Severe scale spallation and weight loss in nitrate melt containing 0.2 % Na2O fostering more rapid corrosion, alarming that substantial tolerance of oxide content in solar salt is ≥ 0.135 % for an acceptable corrosion of 316L SS. Despite preferential dissolution of Cr and scale degradation/spallation with increased oxide content in solar salt, the corrosion layer in all cases comprised of sodium ferrite, and Cr-rich Cr-Fe mixed oxides with the Ni enrichment at the scale-metal interface. Competing processes between oxide scale growth, degradation and dissolution or even spallation has been discussed with an emphasis of Na2O addition to solar salt.
KW - Molten salt corrosion
KW - Solar salt
KW - Thermal energy storage
KW - Stainless steel
KW - Concentrating solar power
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610819
DO - https://doi.org/10.1016/j.solmat.2024.113176
VL - 278
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-61081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Sprechen wir über Korrosion - aber richtig!
N2 - Die Korrosion in ihren zahlreichen Erscheinungsformen beschäftigt Fachleute und Laien. Um-so wichtiger ist es, die einzelnen Phänomene korrekt und eindeutig zu benennen. Nur so kann man eine saubere Beschreibung der Korrosionsvorgänge erreichen und damit in der wörtlichen und schriftlichen Kommunikation richtig verstanden werden. An zahlreichen Beispielen wird der richtige und normgemäße Sprachgebrauch beschrieben.
T2 - Korrosionsschutz in der maritimen Technik
CY - Hamburg, Germany
DA - 29.01.2020
KW - Korrosion
KW - Nomenklatur
PY - 2020
SN - 978-3-935406-72-7
SP - 7
EP - 11
AN - OPUS4-50327
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beck, Uwe
T1 - Materials testing using centrifuge technology a journey through time from 2004 to 2024
N2 - This presentation provides an overview of materials testing using centrifuge technology in the period from 2004 to 2024. The development, the proof of concept, the functional principle, various operating modes as well as applications and examples are shown.
T2 - ICDAMT 2024
CY - Berlin, Germany
DA - 10.06.2024
KW - Centrifuge technology
KW - Materials testing
KW - Centrifugal adhesion testing
KW - Tensile and cmpressive stress testing
PY - 2024
AN - OPUS4-60541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - On the use of spectroscopic imaging ellipsometry for quantification and characterisation of defects in thin films for power electronics
N2 - Compound semiconductors (CS) are promising materials for the development of high-power electrical applications. They have low losses, can withstand high temperatures and can operate at very high voltages and currents. This makes them a key technology for the electrification of many high energy applications, especially electromobility and HVDC power lines.
The challenge with CS technology is that most of the process technology has to be developed anew to the high standards required by electronic applications. Today, compound semiconductors can be produced in thin layers on top of substrates fabricated from classical crystal growth processes that are already well established. A promising method for this is metal organic vapour phase epitaxy (MOVPE). With this method, many different compounds with semiconducting properties can be synthesized. Additionally, this process technology is a direct thin layer deposition method. Therefore, complex multilayer systems can be generated directly by the deposition process and without the need of doping after growing.
There are a number of critical defects that can originate from the deposition process of these thin film devices. Within this project, we intend to develop new correlative imaging and analysis techniques to determine defect types, to quantify defect size and number density, as well as to characterise defects for process optimisation.
We report here on the use of spectroscopic ellipsometry and imaging ellipsometry to investigate defects in several different compound semiconductor materials used in high-power electronic devices. The materials we investigated are β-Ga2O3, SiC, GaN, AlN, and AlGaN materials as well as oxidised SiC surfaces. All of these materials have their typical defects and require optimised measurement and analysis schemes for reliable detection and analysis. Spectroscopic ellipsometry is a highly sensitive method for determining the thicknesses and dielectric function of thin layers, yielding potentially a high number of microscopic properties. The combined method between ellipsometry and optical microscopy is called imaging ellipsometry and is especially powerful for the large amount of data it produces. We have analysed defects in SiC- and AlN-based thin film semiconductors as well as characterised the properties of different types of SiO2 layers created on top of SiC monocrystals. We developed ellipsometric models for the data analysis of the different semiconductor materials.
If the defects have geometric features, it is useful to combine the ellipsometric analysis with topometry method like interference microscopy and scanning probe microscopy. We have successfully characterised function-critical defects in MOVPE SiC layers and correlated the findings with topography from WLIM measurements. We have developed an imaging ellipsometric measurement methodology that allows to estimate the relative defect area on a surface by a statistical raw data analysis.
T2 - EMRS Spring Meeting 2024 - ALTECH 2024
CY - Strasbourg, France
DA - 27.05.2024
KW - compound semiconductors
KW - Ellipsometry
KW - Layer Materials
KW - Defect Analysis
PY - 2024
AN - OPUS4-61005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kempf, A.
A1 - Hilgenberg, Kai
T1 - Einfluss der Porosität auf die Duktilitätseigenschaften von additiv gefertigtem AlSi10Mg
N2 - Die Werkstoffeigenschaften im selektiven Laserstrahlschmelz-Verfahren hergestellter Bauteile werden von einer Vielzahl technologischer Parameter beeinflusst, sodass sich die Fertigungsgüte verschiedener Anlagen voneinander unterscheiden kann. Vor diesem Hintergrund wurde in der vorliegenden Arbeit untersucht, inwiefern sich durch verschiedene nachgelagerte Wärmebehandlungen die Mikrostruktur und die quasistatischen Festigkeitseigenschaften von Proben aus der Aluminiumlegierung AlSi10Mg, die mit verschiedenen Anlagen, Pulvern, Belichtungsstrategien und Prozessparametern gefertigt wurden, harmonisieren lassen. Die Versuche zeigten u.a., dass die erheblichen Festigkeitsunterschiede im Ausgangszustand unabhängig von der angewendeten Wärmebehandlungsroute aufgehoben wurden. Dennoch wurden signifikante Unterschiede in der Duktilität ermittelt. Anhand umfangreicher Bruchflächenanalysen konnte nachgewiesen werden, dass die in der Bruchfläche ermittelte Porosität eine lineare Korrelation zu der Bruchdehnung aufwies.
T2 - 5. Tagung des Arbeitskreises Additiv gefertigte Bauteile und Strukturen
CY - Online Meeting
DA - 04.11.2020
KW - Wärmebehandlung
KW - Additive Fertigung
KW - Laser powder bed fusion
KW - AlSi10Mg
KW - Ringversuch
PY - 2020
SN - 2509-8772
VL - 405
SP - 93
EP - 104
AN - OPUS4-51657
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hofmann, Detlef
A1 - Basedau, Frank
A1 - Heidenreich, F.
A1 - Herten, M.
T1 - Verwendung faseroptischer Messtechnik im Zuge wiederholter Eignungsprüfungen an Verpressankern
N2 - Im Rahmen des Ausbaus des Dortmund-Ems-Kanals wurden an der Schleuse Gleesen Forschungsanker installiert, die Rückschlüsse auf das Tragverhalten in Folge des chemischen Angriffs kalklösender Kohlensäure geben sollen. Die Forschungsanker werden seit der Erstellung im Jahr 2017 mit verteilter faseroptischer Sensorik während der jährlichen Eignungsprüfungen untersucht. Die Ergebnisse der Jahre 2017 bis 2019 werden im Folgenden dargestellt.
T2 - Messen in der Geotechnik 2020
CY - Braunschweig, Germany
DA - 20.02.2020
KW - Faseroptische Sensorik
KW - Rayleigh Rückstreuung
KW - Verpressanker
KW - Chemischer Angriff
KW - Rissbildung
PY - 2020
SN - 978-3-948141-02-8
DO - https://doi.org/10.24355/dbbs.084-201912181435-0
IS - 110
SP - 297
EP - 323
AN - OPUS4-51687
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tian, H.
A1 - Voigt, Marieke
A1 - Lehmann, C.
A1 - Meng, Birgit
A1 - Stephan, D.
ED - Middendorf, B.
ED - Fehling, E.
T1 - Composition and microstructure stability of cement compound under cyclic hydrothermal condition
N2 - There have been many researches focused on the performance improvement of ultra-high performance concrete (UHPC) by autoclaving treatment. The goal of autoclaving is to increase the pozzolanic reaction, and to densify the cement stone and the transition zone which originates from the incorporation of supplementary cementitious materials (SCMs), such as silica fume, fly ash and blast furnace slag. Due to the superior properties, UHPC can also be utilized under high mechanical load and aggressive condition, for example, the fabrication of water tanks for thermal storage which is of great significance for saving energy and reducing CO2 emission. It is known that mineral stability of the hydration products of an inorganic binder is highly related to the temperature and pressure of the environment. A certain stable composition at room temperature, however, may undergo a phase transformation at high temperature and the performance decrease under this severe condition will generally be more severe. In this way, the rationale behind this deterioration under long-term hydrothermal condition involving many cycles and long duration has to be clarified, and then appropriate optimizing methods will be performed in order to obtain a kind of construction with high durability under aggressive environment. For this purpose, different types and amounts of SCMs are introduced into the standard mixture of UHPC and the phase compositions after autoclaving at 200 °C and 15.5 bar are determined by combined X-ray diffraction and scanning electron microscope. Mercury intrusion porosimeter is used to characterise the microstructure of the samples. In order to establish the relationship between microstructure and macroscopic properties, compressive and flexural strength are also investigated.
T2 - HiPerMat 2020
CY - Kassel, Germany
DA - 11.03.2020
KW - Hydrothermal treatment
KW - UHPC
KW - Composition
PY - 2020
SN - 978-3-7376-0828-2
VL - 23
SP - 87
EP - 88
PB - Kassel University Press
CY - Kassel
AN - OPUS4-52375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Kalady, Mohammed Fayis
A1 - Schultz, Johannes
A1 - Weinel, Kristina
A1 - Wolf, Daniel
A1 - Lubk, Axel
T1 - Localization of Hybridized Surface Plasmon Modes on Random Gold Nanoparticle Assemblies
N2 - Assemblies of plasmonic nanoparticles (NPs) support hybridized modes of localized surface plasmons (LSPs), which delocalize in geometrically well-ordered arrangements. Here, the hybridization behavior of LSPs in geometrically completely disordered arrangements of Au NPs fabricated by an e-beam synthesis method is studied. Employing electron energy loss spectroscopy in a scanning transmission electron microscope in combination with numerical simulations, the disorder-driven spatial and spectral localization of the coupled LSP modes that depend on the NP thickness is revealed. Below 0.4nm sample thickness (flat NPs), localization increases towards higher hybridized LSP mode energies. In comparison, above 10nm thickness, a decrease of localization (an increase of delocalization) with higher mode energies is observed. In the intermediate thickness regime, a transition of the energy dependence of the localization between the two limiting cases, exhibiting a transition mode energy with minimal localization, is observed. This behavior is mainly driven by the energy and thickness dependence of the polarizability of the individual NPs.
KW - Plasmonics
KW - Electron-Energy Loss Spectroscopy
KW - Discrete Dipole Approximation
KW - Nanoparticles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618323
DO - https://doi.org/10.48550/arXiv.2410.10514
SP - 1
EP - 8
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-61832
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lauhoff, Christian
A1 - Degener, Sebastian
A1 - Bolender, Artjom
A1 - Liehr, Alexander
A1 - Hübner, Leoni
A1 - Frenck, Johanna-Maria
A1 - Molotnikov, Andrey
A1 - Niendorf, Thomas
T1 - In Situ Synchrotron Diffraction Assessment of Reversibility of the Martensitic Transformation in Single-Crystalline Co–Ni–Ga Shape Memory Alloy Under Torsion
N2 - AbstractHeusler-type Co–Ni–Ga shape memory alloys attracted significant attention due to their excellent functional properties in single-crystalline state under both compressive and tensile loading. The present study investigates the superelastic deformation behavior under torsion. Using a newly installed torsion testing setup, in situ synchrotron diffraction was carried out on single-crystalline material in order to investigate the martensitic phase transformation. Incremental deformation experiments reveal a fully reversible martensitic transformation under torsional loading at room temperature, leading to excellent strain recovery after deformation to 6.5% shear strain. Furthermore, relevant aspects towards the analysis of powder diffraction data obtained for single-crystalline material in transmission mode under torsional loading are presented and critically discussed.
KW - Shape memory alloy
KW - Pseudoelasticity
KW - Martensitic transformation
KW - Synchrotron diffraction
KW - In situ testing
KW - Torsion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621872
DO - https://doi.org/10.1007/s40830-024-00496-8
VL - 10
SP - 326
EP - 333
PB - Springer Science and Business Media LLC
AN - OPUS4-62187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Runze
A1 - Sur, Debashish
A1 - Li, Kangming
A1 - Witt, Julia
A1 - Black, Robert
A1 - Whittingham, Alexander
A1 - Scully, John R.
A1 - Hattrick-Simpers, Jason
T1 - Bayesian assessment of commonly used equivalent circuit models for corrosion analysis in electrochemical impedance spectroscopy
N2 - Electrochemical Impedance Spectroscopy (EIS) is a crucial technique for assessing corrosion of metallic materials. The analysis of EIS hinges on the selection of an appropriate equivalent circuit model (ECM) that accurately characterizes the system under study. In this work, we systematically examined the applicability of three commonly used ECMs across several typical material degradation scenarios. By applying Bayesian Inference to simulated corrosion EIS data, we assessed the suitability of these ECMs under different corrosion conditions and identified regions where the EIS data lacks sufficient information to statistically substantiate the ECM structure. Additionally, we posit that the traditional approach to EIS analysis, which often requires measurements to very low frequencies, might not be always necessary to correctly model the appropriate ECM. Our study assesses the impact of omitting data from low to medium-frequency ranges on inference results and reveals that a significant portion of low-frequency measurements can be excluded without substantially compromising the accuracy of extracting system parameters. Further, we propose simple checks to the posterior distributions of the ECM components and posterior predictions, which can be used to quantitatively evaluate the suitability of a particular ECM and the minimum frequency required to be measured. This framework points to a pathway for expediting EIS acquisition by intelligently reducing low-frequency data collection and permitting on-the-fly EIS measurements.
KW - Electrochemical Impedance Spectroscopy (EIS)
KW - MAPz@BAM
KW - Bayesian Inference
KW - Corrosion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623392
DO - https://doi.org/10.1038/s41529-024-00537-8
VL - 8
SP - 120
PB - Springer Materials
AN - OPUS4-62339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Anforderungen an den Einsatz von Metallen im Trinkwasser
N2 - Die Trinkwasserverordnung gibt regulatorische Vorgaben zum Werkstoffeinsatz. Daneben existieren normative Hinweise zur Beständigkeit der Werkstoffe. Das Zusammenspiel der unterschiedlichen Vorgaben wird dargestellt und diskutiert
T2 - Korrosionsverhalten bleifreier Kupfer-Zink-Legierungen im Kontakt mit Trinkwasser
CY - Dresden, Germany
DA - 11.10.2022
KW - Korrosion
KW - Trinkwasser
KW - Hygiene
KW - Werkstoffe
PY - 2022
AN - OPUS4-55982
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eisenbart, M.
T1 - KupferDigital – Datenökosystem für die digitale Materialentwicklung auf Basis Ontologie-basierter digitaler Repräsentationen von Kupfer und Kupferlegierungen
N2 - Kern des Projektes KupferDigital ist es, einen Demonstrator für ein digitales Datenökosystem zu erstellen, der der Digitalisierung der Materialforschung und der metallverarbeitenden Industrie als zukunftsfähige Plattform zur Verfügung stehen soll. Das Projekt KupferDigital entwickelt Methoden und Konzepte, um den Lebenszyklus am Beispiel von Kupfer – von der Erzgewinnung bis zum Recycling – digital zu erfassen. Grundlage ist die Entwicklung sogenannter Ontologien. Diese können als eine Art Wissensnetz verstanden werden. Sie dienen als gemeinsame Standards für die Beschreibung von Werkstoffen und technischen Vorgängen. Sie helfen bei der digitalen Erfassung von Prozessschritten sowie von Materialeigenschaften. Parallel dazu werden Konzepte für Datenstrukturen, die Speicherung und den Austausch von Werkstoffdaten über neu zu definierende Schnittstellen erarbeitet.
Über die Bereitstellung digitalisierter Lebenszyklen von Kupfer wird die Industrie bei der Pro-duktentwicklung befähigt, neue Werkstoffentwicklungen frühzeitig zu bewerten, beispielsweise unter dem Gesichtspunkt der Nachhaltigkeit. Kupfer kommt hier eine aktuelle Bedeutung zu, weil es für die digitale Transformation sowie die Energie- und Mobilitätswende von fundamentaler Bedeutung ist und somit von hohem gesellschaftlichem Wert. Die Projektziele sind sowohl auf weitere metallische Struktur- und Funktionswerkstoffe als auch auf andere Industriebereiche übertragbar.
Die Projektergebnisse werden im Rahmen der Aktivitäten der Innovationsplattform MaterialDigital allen Interessierten zur Verfügung gestellt.
T2 - MatFo2022 „Vom Material zur Innovation: Digital, Neutral, Vital“
CY - Online meeting
DA - 14.11.2022
KW - Kupfer
KW - Datenökosystem
KW - Materialentwicklung
KW - Ontologie
PY - 2022
AN - OPUS4-56405
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - What can we learn from polymer degradation by radiation?
N2 - It is discussed what can be learned from polymer degradation, especially of biopolymers such as DNA and proteins. Synergetci effects of combining methods for structural and chemical analysis as well as Monte-Carlo simulations are presented.
T2 - Material Strategy
CY - Beelitz, Germany
DA - 12.10.2022
KW - Polymer
KW - Polymer degradation
KW - DNA
KW - Protein
KW - XPS
KW - ESEM
KW - Raman
KW - MCS
KW - Monte-Carlo Simulations
PY - 2022
AN - OPUS4-56123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 53, Heft 1
T3 - Amts- und Mitteilungsblatt der BAM - 1/2023
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574038
SN - 0340-7551
VL - 53
IS - 1
SP - 1
EP - 340
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-57403
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolff, M.
A1 - Wonneberger, R.
A1 - Freiberg, K.E.
A1 - Hertwig, Andreas
A1 - Bonse, Jörn
A1 - Giebeler, L.
A1 - Koitzsch, A.
A1 - Kunz, C.
A1 - Weber, H.
A1 - Hufenbach, J.K.
A1 - Müller, F.A.
A1 - Gräf, S.
T1 - Formation of laser-induced periodic surface structures on Zr-based bulk metallic glasses with different chemical composition
N2 - Bulk metallic glasses (BMG) are amorphous metal alloys known for their unique physical and mechanical properties. In the present study, the formation of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on the Zr-based BMGs Zr46Cu46Al8, Zr61Cu25Al12Ti2, Zr52.5Cu17.9Al10Ni14.6Ti5 (Vit105) and Zr57Cu15.4Al10Ni12.6Nb5 (Vit106) was investigated as a function of their different chemical composition. For this purpose, LIPSS were generated on the sample surfaces in an air environment by fs-laser irradiation (λ = 1025 nm, τ = 300 fs, frep = 100 kHz). The surface topography was characterized by scanning electron microscopy and atomic force microscopy. Moreover, the impact of LIPSS formation on the structure and chemical surface composition was analyzed before and after fs-laser irradiation by X-ray diffraction and X-ray photoelectron spectroscopy as well as by transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. Despite the different chemical composition of the investigated BMGs, the fs-laser irradiation resulted in almost similar properties of the generated LIPSS patterns. In the case of Zr61Cu25Al12Ti2, Vit105 and Vit106, the surface analysis revealed the preservation of the amorphous state of the materials during fs-laser irradiation. The study demonstrated the presence of a native oxide layer on all pristine BMGs. In addition, fs-laser irradiation results in the formation of laser-induced oxide layers of larger thickness consisting of an amorphous ZrAlCu-oxide. The precise laser-structuring of BMG surfaces on the nanoscale provides a versatile alternative to thermoplastic forming of BMG surfaces and is of particular interest for the engineering of functional material surfaces.
KW - Bulk metallic glasses
KW - Femtosecond laser
KW - Laser-induced periodic surface structures (LIPSS)
KW - Chemical analysis
KW - Oxidation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581799
DO - https://doi.org/10.1016/j.surfin.2023.103305
SN - 2468-0230
VL - 42
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-58179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 53, Heft 3
T3 - Amts- und Mitteilungsblatt der BAM - 3/2023
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585302
SN - 0340-7551
VL - 53
IS - 3
SP - 463
EP - 516
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-58530
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Porta-Velilla, L.
A1 - Martínez, E.
A1 - Frechilla, A.
A1 - Castro, M.
A1 - de la Fuente, G. F.
A1 - Bonse, Jörn
A1 - Angurel, L. A.
T1 - Grain orientation, angle of incidence, and beam polarization effects on ultraviolet 300 ps-laser-induced nanostructures on 316L stainless steel
N2 - Laser-induced periodic surface structures (LIPSS) represent a unique route for functionalizing materials through the fabrication of surface nanostructures. Commercial AISI 316L stainless steel (SS316L) surfaces are laser treated by ultraviolet 300 ps laser pulses in a laser line scanning (LLS) approach. Processing parameters are optimized (pulse energy of 2.08 µJ, pulse repetition frequency of 300 kHz, and suitable laser scan and sample displacement rates) for the generation of low spatial frequency LIPSS over a large 25 × 25 mm2 area. Different angles of incidence of the laser radiation (0°, 30°, and 45°) and different linear laser beam polarizations (s and p) produce a plethora of rippled surface morphologies at distinct grains. Scanning electron microscopy and 2D Fourier transforms, together with calculations of the optical energy deposited at the treated surfaces using Sipe's first-principles electromagnetic scattering theory, are used to study and analyze in detail these surface morphologies. Combined with electron backscattering diffraction, analyses allow associating site-selectively various laser-induced-surface morphologies with the underlying crystalline grain orientation. Resulting grain orientation maps reveal a strong impact of the grain crystallographic orientation on LIPSS formation and point toward possible strategies, like multi-step processes, for improving the manufacturing of LIPSS and their areal coverage of polycrystalline technical materials.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Steel
KW - Grain orientation
KW - Electron backscattering diffraction (EBSD)
KW - Laser processing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588929
DO - https://doi.org/10.1002/lpor.202300589
SN - 1863-8899
SP - 1
EP - 21
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-58892
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Helmholtz-AK "Bau wissenschaftlicher Geräte" - Neues aus der BAM / Fachbereich 9.2
N2 - In dieser Präsentation werden die neuesten Herausforderungen und der Stand des Fachbereiches 9.2 für die Mitarbeit im AK des HGF "Bau wissenschaftlicher Geräte" dargestellt.
T2 - Helmholtz-Arbeitskreis "Bau wissenschaftlicher Geräte", 18. Jahrestagung
CY - Berlin, Germany
DA - 10.05.2023
KW - Werkstatt
KW - Erneuerbare Energien
PY - 2023
AN - OPUS4-59262
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krauklis, A. E.
A1 - Starovka, O.
A1 - Gibhardt, D.
A1 - Aouissi, H. A.
A1 - Burlakovs, J.
A1 - Sabalina, A.
A1 - Fiedler, Bodo
A1 - Kalinka, Gerhard
T1 - Reversible and irreversible effects on the epoxy GFRP fiber-matrix interphase due to hydrothermal aging
N2 - Epoxy R-Glass Fiber-Reinforced Polymer (GFRP) composite plates were hydrothermally aged at 60 ◦C for 23, 75, and 133 days. The water content reached 0.97 wt%, 1.45 wt% and 1.63 wt%, respectively. The studied GFRP matrix was inert to hydrolysis or chain scission, allowing for investigation of irreversible changes in the fiber-matrix interphase due to hydrothermal aging upon re-drying. During each period, a subset of the specimens was removed from the water bath and dried in a chamber. The weight loss upon drying was explained with epoxy leaching (impurities), sizing-rich interphase hydrolysis, glass fiber surface hydrolysis, accumulated degradation products escaping, and water changing state from bound to free. The influence of hydrothermal aging on the fiber-matrix interfacial properties was investigated. Lower interfacial strength of hydrothermally aged (wet)
samples was attributed to plasticization of the epoxy, plasticization and degradation of the sizing-rich interphase (including formation of hydrolytic flaws), and hydrolytic degradation of the glass fiber surface. The kinetics of epoxy-compatible epoxysilane W2020 sizing-rich interphase hydrolysis provided an estimate of ca. 1.49%, 4.80%, and 8.49% of the total composite interphase degraded after 23, 75, and 133 days, respectively. At these conditions, the interface lost 39%, 48%, and 51% of its strength. Upon re-drying the specimens, a significant part of the interfacial strength was regained. Furthermore, an upward trend was observed, being 13%, 10% and 3% strength, respectively; thus, indicating a possibility of partial recovery of properties.
KW - GFRP
KW - Hydrothermal Ageging
KW - Interphase
KW - Water Diffusion
KW - Desorption
KW - Interfacial Strength
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581554
DO - https://doi.org/10.1016/j.jcomc.2023.100395
SN - 2666-6820
VL - 12
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-58155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 53, Heft 4
T3 - Amts- und Mitteilungsblatt der BAM - 4/2023
KW - Anerkennungen
KW - Zulassungen
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592823
SN - 0340-7551
VL - 53
IS - 4
SP - 517
EP - 540
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-59282
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
T1 - 1H NMR Relaxometry: A Reliable Tool for Predicting Durability Properties?
N2 - Resistance to carbonation and chloride migration are critical durability properties in cementitious construction materials. The ingress of CO2 and chlorides can lead to concrete deterioration and reinforcement corrosion, underscoring the importance of ensuring high resistance to these durability-reducing factors. Traditional methods, such as determinating the carbonation coefficient using standard procedures, are time-consuming and resource-intensive. These tests typically require 42 days of preconditioning, followed by 70 days before the final results can be determined using a phenolphthalein test, for a total duration of 112 days. In addition, some test chambers can only accommodate four samples at a time.
In this study, we investigate whether 1H NMR relaxometry can effectively predict not only the carbonation resistance, KAC,3%, but also the chloride migration coefficient, DRCM, and the compressive strength, fc, of concrete, providing a method that could potentially streamline and accelerate the material development process by directing us quickly to potentially well-suited formulations. We performed measurements on non-carbonated fully saturated concrete and mortar samples at 28, 56, and 92 days using the NMR tomograph at BAM (8.9 MHz). Notably, the NMR measurements taken at 28 days showed no significant differences, suggesting that this timeframe is sufficient for meaningful results. The samples analyzed were drill cores, each 70 mm in diameter and approximately 120 mm in height. The NMR features we focused on included the initial amplitude E0, the x and y values of the dominant T2 relaxation time, and the logarithmic mean of the T2 relaxation time distribution. Another key feature was the surface relaxivity, which was determined by comparing the NMR curves with results from mercury intrusion porosimetry. We examined the correlation of these NMR features with the aforementioned durability properties, which were determined in a laboratory on sister samples using standard procedures. No chloride migration tests were performed on the mortar samples, and the carbonation procedure was carried out unter atmospheric conditions.
The preliminary results show that the correlation factors for the NMR features with the carbonation coefficients of concrete were particularly remarkable. The strongest correlations were observed for the dominant relaxation time and the logarithmic mean, with values approaching 1. The preliminary results also indicate that there are high correlations between the compressive strength and amplitude-related features. In contrast, no strong correlations are observed for the DRCM. Although the results related to the mortar samples are still being analyzed, these initial correlations suggest that 1H NMR relaxometry could be a valuable tool for early assessment of material properties. Furthermore, the rapid and non-destructive nature of NMR measurements, requiring only a few minutes per sample, suggests that this technique has the potential to significantly accelerate the process of evaluating durability properties in cementitious materials. This capability also paves the way for the use of NMR features as input for AI-driven predictive models.
T2 - Magnetic Resonance in Porous Media 2024
CY - Tromso, Norway
DA - 26.08.2024
KW - Nuclear magnetic resonance
KW - SLAMD
KW - Carbonation
KW - Durability
PY - 2024
AN - OPUS4-61058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schwettmann, K.
A1 - Stephan, D.
A1 - Nytus, N.
A1 - Radenberg, M.
A1 - Weigel, Sandra
T1 - Post carbon road - The endless cycle of bitumen reuse
N2 - In Germany, the reuse of asphalt has a long tradition. Since the 1980s, the reclaimed asphalt has been recycled achieving a reuse rate of around 90% and thus a very high value in the last years. In the future, instead of the amount, the quality of the reclaimed asphalt will be more important because the recycled asphalt will be reused again and again. Thus, these asphalt mixes are in the second or even third cycle of reuse. Concerning this situation, the question arises if asphalt can be reused several times without any loss in quality. An important factor affecting the asphalt quality is the binder bitumen. During the production, construction and service life, the ageing of this binder occurs causing a hardening of the bitumen. To compensate this hardening, additives for the reclaimed asphalt in terms of rejuvenation agents (rejuvenators) gain in importance. With these rejuvenators, the physical properties of bitumen can be modified e.g. the hardness and the stiffness reduced. However, the mechanism of the rejuvenation agents and the effects of the bitumen chemistry are largely unknown because the composition of the products varies very strongly. But with growing knowledge about these mechanisms and effects of the rejuvenation agents, the chemical composition and thus the physical and ageing behavior of bitumen can be targeted modified by the use of suitable rejuvenators. In this work, the actual results of the project Postcarbone road should be presented including investigations about the chemical and physical mechanisms as well as the efficiency of different rejuvenators.
Further, a model for the cyclic reuse of bitumen should be developed. Based on this model, the choice of a suitable rejuvenation agent for the considered bitumen or rather asphalt should be possible. The project Postcarbone road (392670763) is funded by the German Research Foundation (DFG).
T2 - 7th Eurasphalt and Eurobitume Comgress
CY - Online meeting
DA - 15.06.2021
KW - Bitumen
KW - Multiple ageing and rejuvenation
KW - Conventional testing
KW - DSR
KW - BBR
KW - FTIR
KW - Asphaltene content
KW - Column chromatography
PY - 2021
SP - 1
EP - 14
AN - OPUS4-53490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
T1 - Study on the predictability of carbonation resistance of cementitous materials based on nmr features and the use of slamd
N2 - This study explores the acceleration of material design in the concrete industry, focusing on improving carbonation resistance, a key factor in the durability of concrete structures. Traditional tests for carbonation resistance are lengthy, but with the construction industry aiming for sustainable production, finding a balance between carbonation resistance and CO2 footprint is crucial. Our research employs two innovative methods: 1. Applying the Sequential Learning App for Materials Discovery (SLAMD), an AI materials design framework, to an extensive dataset of real-world concrete compositions to selectively test materials that meet market demands: maximum durability, optimal eco-durability, and the best cost-durability trade-off. 2. Investigating 1H Nuclear Magnetic Resonance (NMR) relaxometry as a quick alternative for characterizing carbonation behavior, as it saves time compared to traditional tests and assesses the complete material's pore space. Specific NMR features are then integrated into the material design model, with the model's performance compared against traditional approaches. The results of our study are compelling, demonstrating that materials can be precisely tailored to meet specific requirements with minimal data points. This marks a significant stride in the concrete industry, indicating that NMR-based, low-fidelity surrogate characterizations, combined with a focused, data-driven design approach, can substantially accelerate the development of durable, sustainable concrete mixtures.
T2 - Rilem Spring Convention & Conference
CY - Milan, Italy
DA - 10.04.2024
KW - Nuclear magnetic resonance
KW - Carbonation resistance
KW - Cement and concrete
KW - SLAMD app
KW - Predictability
PY - 2024
AN - OPUS4-60000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
A1 - Müller, U.
A1 - Hüsken, Götz
A1 - Gardei, Andre
T1 - Begutachtung Berliner Tuffsteinfassaden - Turmruine der Kaiser-Wilhelm-Gedächtniskirche und Charlottenburger Tor
N2 - Am Ende des 19. und zu Beginn des 20. Jahrhunderts wurden auch in Berlin vermehrt Bauwerke mit einer Fassadenverblendung aus Eifeler Tuffsteinen errichtet. Die Eifeler Tuffsteine zeichnen sich aufgrund ihrer hohen Porosität einerseits durch eine gute Verarbeitbarkeit aus. Andererseits sind sie nur schwach gebunden und besitzen deshalb eine geringe Verwitterungsbeständigkeit.
T2 - Workshop Kulturguterhaltung - Vom Dampfkessel zu Nanomaterialien
CY - Berlin, Germany
DA - 17.11.2021
KW - Fassade
KW - Tuffstein
KW - Schalenbildung
PY - 2021
SN - 2567-1251
VL - 3
SP - 107
EP - 123
PB - Druckerei G. Bohm
CY - Berlin
AN - OPUS4-54461
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stohl, Leonie
T1 - Funktionalisierter Beton: Biorezeptivität von strukturiertem UHPC
N2 - Understanding the fundamentals of bioreceptivity enables the developement of functionalized materials. Concrete as the most used building material worldwide is of special interest as microbially greened panels may represent an alternative to classic façade greening with plants.
As standards are not ye established, material characterization in context as well as bioreceptivity assessment itself has been proven to be difficult. The presentation reviews first results of methods adapted for this application.
T2 - Tagung des Instituts für Bioanalytik: Bewertung biozidhaltiger Baustoffe
CY - Augsburg, Germany
DA - 29.06.2023
KW - Biorezeptivität
KW - Beton
KW - UHPC
KW - Biofilm
PY - 2023
AN - OPUS4-58375
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Nielow, Dustin
T1 - Einfluss fertigungsbedingter Imperfektionen auf die Schwingfestigkeit von FKV-Schalenstrukturen in Sandwichbauweise
N2 - Rotorblätter von Windenergieanlagen (WEA) weisen häufig nach wenigen Jahren, lange vor dem Erreichen der prognostizierten Lebensdauer von 20 bis 30 Jahren Risse in der Blattschale auf. Die Folge sind aufwendige Reparaturen am installierten und schwer zugänglichen Rotorblatt und der kostenintensive Nutzungsausfall durch den Stillstand der WEA.
Als mögliche Initiatoren für die Schäden in der Blattschale der Rotorblätter gelten fertigungsbedingte Imperfektionen. Für die Untersuchung des Einflusses dieser Imperfektionen auf das Ermüdungsverhalten der Rotorblätter wurde an der BAM (Bundesanstalt für Mate-rialforschung und -prüfung) ein Prüfstand für statische und zyklische Versuche von Schalensegmenten im intermediate scale entwickelt und betrieben. Die untersuchten Schalensegmente in Sandwichbauweise sind der Rotorblattschale von WEA im Hinblick auf die Strukturmechanik, die eingesetzten Halbzeuge, den Laminataufbau und dem eingesetzten Fertigungsverfahren ähnlich. Als Imperfektionen wurden verschiedenen Variationen von Lagenstößen in die Hautlagen und Schaumstöße mit Breitenvariation in den Stützkern reproduzierbar eingebracht. Die Überwachung des Schädigungszustandes während der Schwingversuche unter realistischen Lastszenarien erfolgt über eine kombinierte in situ Schädigungsüberwachung mittels passiver Thermografie und Felddehnungsmessung.
Mit den durchgeführten Schwingversuchen und der begleitenden Überwachung des Schädigungszustandes ließen sich die Schadensinitiation und die signifikante Herabsetzung der Lebensdauer durch die eingebrachten Imperfektionen zweifelsfrei nachweisen und entsprechende Konstruktionshinweise für die betriebssichere Auslegung von Sandwichstrukturen ableiten.
N2 - Wind turbines often exhibit cracks in the blade shells after only a few years in service, significantly before their expected 20 to 30 year design lifespan. This leads to complicated repairs on difficult to reach rotor blades, and can cause a cost-intensive standstill of the turbine.
A possible source of these defects in the rotor blade shells are the imperfections which occur during production. In order to investigate the effect of these imperfections on the fatigue behavior of rotor blades, a test rig was developed at the BAM (Bundesanstalt für Materialforschung und -prüfung) upon which intermediate scale static and cyclic-fatigue testing could be performed. The complementary sandwich shell specimens developed and investigated with the test rig are representative of the outer shell of wind turbine rotor blades in terms of materials and manufacturing processes, as well as structural mechanics. The specimens were built with reproducible imperfections, including laminate overlaps in the face sheets and gaps of varying size in the foam core. The damage condition was monitored during cyclic-fatigue testing under realistic load cases using a combination of in-situ passive thermography and strain field measurement.
The cyclic testing and parallel non-destructive structural health monitoring of the shell specimens showed the imperfections to significantly influence the damage initiation and decrease the component service life. The results can be used accordingly as recommendations for operationally more reliable design of sandwich structures.
T3 - BAM Dissertationsreihe - 170
KW - Erneuerbare Energien
KW - Windenergie
KW - Verbundwerkstoffe
KW - Betriebsfestigkeit
KW - Komponentenprüfung
KW - Renewable ernergy
KW - Wind energy
KW - Intermediate scale
KW - Composites
KW - Fatigue
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546701
SN - 1613-4249
VL - 170
SP - 1
EP - 178
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54670
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Kraus, David
T1 - Ermüdungsverhalten von Glasfaser-Kunststoff-Verbunden unter thermomechanischer Beanspruchung
N2 - Die Werkstoffgruppe der Faser-Kunststoff-Verbunde (FKV) hat sich aufgrund ihrer hervorragenden Leichtbaueigenschaften unter anderem im Sportgerätebau, in der Luft- und Raumfahrt und in der Windenergieindustrie etabliert. Die so hergestellten Strukturen sind in der Regel nicht nur mechanischen Belastungen, sondern auch thermischen Lasten in einem breiten Temperaturspektrum ausgesetzt. Dennoch ist die Auswirkung des Temperatureinflusses bei einer Kombination von thermischer und mechanischer Last auf die Lebensdauer von Strukturen aus FKV bisher nur wenig untersucht.
Im Rahmen dieser Arbeit wird der Einfluss von Temperaturen zwischen 213 K und 343 K auf einen Glasfaser-Epoxidharz-Verbund experimentell untersucht. Das Material wird in diesem Temperaturbereich eingehend charakterisiert: Es werden sowohl die thermomechanischen Eigenschaften von Faser- und Matrixwerkstoff als auch die des Verbundes ermittelt. In einem weiteren Schritt wird dann der Einfluss der Temperatur auf die Schädigungsentwicklung im quasi-statischen Lastfall sowie unter schwingender Ermüdungsbeanspruchung bei verschiedenen FKV-Mehrschichtverbunden analysiert.
Basierend auf den experimentellen Daten wird ein Zusammenhang zwischen der Schädigung und der Anstrengung der Matrix innerhalb der Einzelschicht demonstriert. Die Matrixanstrengung wird mithilfe eines mikromechanischen Modells unter Berücksichtigung der thermomechanischen Eigenspannungen analytisch berechnet. Bei Querzugbeanspruchung kann gezeigt werden, dass eine Vorhersage der Schädigung in Abhängigkeit der Volumenänderungsenergie innerhalb der Matrix getroffen werden kann.
Mithilfe des Konzepts der Matrixanstrengung ist eine Vorhersage der Lebensdauer des Werkstoffs unter schwingender Ermüdungsbeanspruchung in Abhängigkeit der Einsatztemperatur möglich.
N2 - Due to their superior lightweight properties, fiber reinforced polymer (FRP) materials are well established in various fields, such as sports equipment, aerospace or wind energy structures.
These structures are not only subjected to mechanical loads, but also to a broad spectrum of thermal environments. However, the impact of temperature on the fatigue life of thermomechanically loaded FRP structures is barely investigated to-date.
In the scope of this work, the influence of temperatures in a range of 213 K to 343 K on a glass fiber reinforced epoxy polymer is experimentally examined. An extensive thermo-mechanical characterization of the static properties of the material is performed. The neat resin and Fiber material are investigated, as well as the composite. In addition, the impact of thermal loads on the damage evolution under quasi-static as well as cyclic fatigue loading is investigated for different multi-angle laminates.
Based on the experimental data, a correlation is shown between damage and matrix effort of the unidirectional layer. The matrix effort is calculated according to a micromechanical model considering thermal residual stresses. Particularly under transverse loading, the damage Evolution can be predicted as a function of the dilatational strain energy of the matrix.
Using the concept of the matrix effort presented in this work, a prediction of the fatigue life of the investigated material at different ambient temperature conditions can be performed.
T3 - BAM Dissertationsreihe - 169
KW - Ermüdung
KW - Faser-Kunststoff-Verbund
KW - GFK
KW - Schädigung
KW - Thermomechanik
KW - Fatigue
KW - Composite
KW - Glas fibre reinforced polymer
KW - Damage
KW - Thermomechanics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530253
SN - 1613-4249
VL - 169
SP - 1
EP - 164
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-53025
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - X-ray generation
N2 - This talk was recorded during the 2020 Better with Scattering workshop held at BAM in Berlin. This educational talk explains the various ways in which X-rays can be generated in the lab as well as at the synchrotron, with benefits and drawbacks for all.
T2 - Better with Scattering workshop 2020
CY - BAM, Berlin, Germany
DA - 16.03.2020
KW - Small angle scattering
KW - X-ray instrumentation
KW - X-ray generation
PY - 2020
UR - https://www.youtube.com/watch?v=Hze3PvcK7es
AN - OPUS4-51016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - A brief history of scattering
N2 - Recorded on the first day of the Better with Scattering workshop. In this video, I explore some of the highlights of the development of small-angle X-ray scattering over its long history. I discuss developments on the technical side, analytical methods, detectors, data quality and data management.
T2 - Better with Scattering workshop 2020
CY - BAM, Berlin, Germany
DA - 16.03.2020
KW - Small angle scattering
KW - History
PY - 2020
UR - https://www.youtube.com/watch?v=mFH6P4tZbyM
AN - OPUS4-51015
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulz, Wencke
T1 - High temperature corrosion phenomena of HEAs and MEAs
N2 - High- and medium-entropy alloys (HEAs and MEAs) constitute a new class of materials. Those with a face-centered cubic (fcc) structure from the Cr-Mn-Fe-Co-Ni system have excellent mechanical properties and are considered for high-temperature applications since diffusion in these alloys was reported to be sluggish. However, their corrosion resistance at high temperatures must still be evaluated to further qualify them for such kinds of applications.
Various groups studied the oxidation behavior of HEAs and MEAs under (dry) laboratory and artificial air as well as CO2/CO mixtures in different temperature ranges. CrCoNi exhibits the best corrosion resistance at 800 °C due to the formation of a protective Cr2O3 layer. The matrix below the oxide scale was reported to be correspondingly depleted in Cr. It was further shown that the addition of Mn and Fe to CrCoNi changes the phase composition of the oxide scale at 800 °C. A Mn2O3 layer was grown during oxidation on CrMnCoNi and CrMnFeCoNi and a Cr2O3 scale was formed at the matrix/oxide scale interface. Beneath these oxide layers, Mn- and Cr-depleted zones were detected. These phase morphologies demonstrate the inward diffusion of oxygen and outward diffusion of Cr and Mn resulting in the formation of Cr2O3 and Mn2O3.
In the present study, the corrosion resistance of CrMnFeCoNi and CrCoNi were confirmed and additionally characterized under further oxidizing atmospheres at 800 °C including Ar-2 Vol.% O2, Ar-2 Vol.% H20, and Ar-2 Vol.% SO2 mixtures.
T2 - Symposium on Advanced Mechanical and Microstructural Characterization of High-Entropy Alloys
CY - Ruhr-Universität Bochum, Germany
DA - 03.02.2020
KW - Mn3O4
KW - High-entropy alloy
KW - Medium-entropy alloy
KW - High-temperature corrosion
KW - Chromia
PY - 2020
AN - OPUS4-50984
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Scattering is a powerful tool to follow nucleation and growth of minerals from solutions
N2 - In recent years, we have come to appreciate the astounding intricacy of the processes leading to the formation of minerals from ions in aqueous solutions. The original, and rather naive, ‘textbook’ image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. Does it, however, mean that all the minerals grow through intermediate phases, following a non-classical pathway?
In general, the precursor or intermediate species constitute different, often short-lived, points along the pathway from dissolved ions to the final solids (typically crystals in this context). In this regard synchrotron-based scattering (SAXS/WAXS/total scattering) appears to be the perfect tool to follow in situ and in a time-resolved manner the crystallization pathway because of the temporal and spatial length scales that can be directly accessed with these techniques. In this presentation we show how we used scattering to probe the crystallisation mechanisms of calcium sulfate, This system contains minerals that are widespread in diverse natural environments, but they are also important in various industrial settings. Our data demonstrate that calcium sulfate precipitation involves formation and aggregation of sub-3 nm anisotropic primary species. The actual crystallisation and formation of imperfect single crystals of calcium sulfate phases, takes place from the inside of the in itial aggregates. Hence, calcium sulfate follows a non-classical pathway.
T2 - X-ray Powder Diffraction at DESY - new opportunities for research and industry
CY - Online meeting
DA - 22.06.2020
KW - Nucleation
KW - Calcium sulfate
KW - Diffraction
KW - Scattering
KW - Synchrotron
KW - SAXS/WAXS
PY - 2020
AN - OPUS4-50943
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Simulaciónes de Montecarlo II: El scoring en las superficies
N2 - En esta presentación desarrollaremos un ejemplo de aplicación para la dispersión de partículas utilizando el método de simulación de Monte- Carlo. Se discutirá el caso de las nanopartículas de oro radiactivo y como obtener informacions sobre diferente tipos de particulas pasando las superfices.
T2 - Seminar of the bioanalysis group
CY - Universidad Nacional de Colombia, Medellin, Colombia
DA - 16.03.2020
KW - Geant4
KW - Geant4-DNA
KW - MCS
KW - Particle scattering simulation
KW - Particle scattering simulations
KW - Radioactive decay
KW - Radioactive nanoparticle
KW - Desintegracion radioactiva
KW - Geant4
KW - Monte-Carlo simulations
KW - Método de Montecarlo
KW - Topas
KW - nanoparticula
PY - 2020
AN - OPUS4-50564
LA - spa
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Setup of a Particle Scattering Simulation environment
N2 - A step by step introduction to the setup of a particle scattering simulation is given. Followed by an installation session.
T2 - Seminar of the bioanalysis group
CY - Universidad Nacional de Colombia, Medellin, Columbia
DA - 12.02.2020
KW - Geant4
KW - Geant4-DNA
KW - MCS
KW - Monte-Carlo simulations
KW - Particle scattering simulations
KW - Scattering
KW - Simulations
KW - Debian
KW - Linux
KW - Topas
KW - C++
KW - Topas-nbio
KW - Git
KW - Cmake
PY - 2020
AN - OPUS4-50366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Sprechen wir über Korrosion - aber richtig!
N2 - Die Korrosion in ihren zahlreichen Erscheinungsformen beschäftigt Fachleute und Laien. Um-so wichtiger ist es, die einzelnen Phänomene korrekt und eindeutig zu benennen. Nur so kann man eine saubere Beschreibung der Korrosionsvorgänge erreichen und damit in der wörtlichen und schriftlichen Kommunikation richtig verstanden werden. An zahlreichen Beispielen wird der richtige und normgemäße Sprachgebrauch beschrieben.
T2 - Korrosionsschutz in der maritimen Technik
CY - Hamburg, Germany
DA - 29.01.2020
KW - Korrosion
KW - Nomenklatur
PY - 2020
AN - OPUS4-50328
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Basics and applications of good SAXS: Quantifying the fine structure of lots of materials
N2 - In contrast to the crisp, clear images you can get from electron microscopy, small-angle X-ray scattering (SAXS) patterns are rather featureless. These patterns, however, contain averaged structural information of all of the finest material structures that were illuminated by the X-ray beam. With careful and precise investigation, and supplementary information from complementary techniques, this bulk material structure can be quantified to reveal structural information spanning four or even five decades in size. Additionally, while the data correction and analysis is complex, sample preparation is very straightforward, also allowing for in-situ and operando measurements to be performed without breaking a sweat. In the right hands, then, this technique can be the most powerful tool in your analytical arsenal.
T2 - OpTecBB webinar within the scope of the focus area Optical Analytics
CY - Online meeting
DA - 27.05.2020
KW - Small-angle scattering
KW - Introduction
KW - Application
KW - Saxs
KW - Nanomaterials
KW - Nanostructure
PY - 2020
UR - https://www.youtube.com/watch?v=mXkYL3dSsTY
UR - https://optecbb.de/veranstaltungen/veranstaltung/webinar-basics-and-applications-of-good-saxs-1238/
AN - OPUS4-50879
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Ejemplos de simulaciónes de Montecarlo La desintegración radioactiva
N2 - A walkthrough how to setup radioactive sources in monte-carlo particle scattering simulations and perform different types of scorings.
N2 - En esta presentación desarrollaremos un ejemplo de aplicación para la dispersión de partículas utilizando el método de simulación de Monte- Carlo. Se discutirá el caso de las nanopartículas de oro radiactivo y los diferentes tipos del scoring.
T2 - Seminar of the bioanalysis group
CY - Universidad Nacional de Colombia, Medellin, Columbia
DA - 27.02.2020
KW - MCS
KW - Geant4-DNA
KW - Geant4
KW - Radioactive nanoparticle
KW - Radioactive decay
KW - Particle scattering simulations
KW - Particle scattering simulation
KW - Topas
KW - Monte-Carlo simulations
KW - Desintegracion radioactiva
KW - Método de Montecarlo
KW - Geant4
KW - nanoparticula
PY - 2020
AN - OPUS4-50472
LA - spa
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Neue Erkenntnisse zum Korrosionsverhalten von Zink an der Atmosphäre
N2 - Die Untersuchungen und Ausführungen im Vortrag belegen, dass verfügbare Modellvorstellungen zur Beschreibung der Deckschichtbildung und Korrosion von Zink unter aktuellen atmosphärischen Bedingungen in Europa nicht mehr gültig sind und neu bewertet werden müssen. So können beispielsweise bisher verfügbare Prognosemodelle den Korrosionsfortschritt nicht mehr ausreichend beschreiben, da durch die Verringerung des Schwefeldioxidgehaltes der Luft veränderte Mechanismen vorliegen.
T2 - 69. Sitzung des NA 062-01-71 AA "Korrosion und Korrosionsschutz"
CY - Berlin, Germany
DA - 27.02.2020
KW - Korrosion
KW - Zink
KW - Atmosphärische Korrosion
KW - Korrosionsprüfung
KW - Deckschichtbildung
KW - gelartige Elektrolyte
PY - 2020
AN - OPUS4-50479
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heise, Svenja
T1 - Normentwurf für ein Prüfverfahren zur Bestimmung von Deckschichtwiderständen an Zinküberzügen mittels gelartiger Elektrolyte (WIPANO - GELELEK)
N2 - Der Vortrag stellt eine Ergebniszusammenfassung des WIPANO-Vorhabens GELELEK im Hinblick auf eine Normung dar. Dafür wird das Projekt zunächst kurz vorgestellt, um anschließend auf normungsrelevante Parameter einzugehen. Dazu gehören insbesondere die Umgebungs- und Messbedingungen, die Herstellungsparameter der Gelpads, das Messverfahren selbst sowie die messbaren Proben. Ein erster Ausblick auf den Normvorschlag wird gegeben.
T2 - 14. Sitzung des NA 062-01-77 AA „Korrosionsprüfverfahren“
CY - Berlin, Germany
DA - 26.02.2020
KW - Deckschichtbildung
KW - Gelartige Elektrolyte
KW - Korrosion
KW - Korrosionsprüfung
KW - Zinküberzüge
KW - Atmosphärische Korrosion
PY - 2020
AN - OPUS4-50536
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Beschreibung der Deckschichtbildung bei Zink und Zinklegierungen mittels minimalinvasiver Korrosionsuntersuchungen und analytischer Methoden (MINIMAL)
N2 - Der Vortrag stellt ein neuartiges Korrosionsprüfverfahren für Zinküberzüge auf Basis gelartiger Elektrolyte vor und führt die Vorteile gegenüber konventionellen Prüfverfahren auf. Basierend auf den Ergebnissen wird die Idee für einen IGF-Projektantrag in Kooperation mit dem Fraunhofer IKTS vorgestellt.
T2 - Web-Meeting GAV-Forschungsbeirat
CY - Online meeting
DA - 29.04.2020
KW - Deckschichtbildung
KW - Zink
KW - Korrosionsprüfung
KW - Gelartige Elektrolyte
PY - 2020
AN - OPUS4-50718
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Werkstoffe im Kontakt mit Trinkwasser: Der Weg nach Europa
N2 - Die Veränderungen bei der Regulierung der Werkstoffe im Kontakt mit Trinkwasser durch die neue EU-Trinkwasserrichtlinie werden erläutert. Folgen für die etablierten Werkstoffe und Verfahren werden aufgezeigt
T2 - DVGW- Bezirksgruppenveranstaltung Berlin/Potsdam
CY - Online meeting
DA - 15.04.2025
KW - Korrosion
KW - Metallmigration
KW - Trinkwasser
PY - 2025
AN - OPUS4-62985
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Metall - Migration in der Trinkwasserinstallation
N2 - Der grundsätzliche Mechanismus der Metallmigration wird erläutert, die gesetzlichen Regeln erläutert. Die Veränderungen, die sich aus der neuen EU-Trinkwasserrichtlinie für den Werkstoffeinsatz ergeben, werden erläutert. Beispiele für die Vorgehensweise werden gezeigt, ein Ausblick für die Umsetzung bildet den Abschluss.
T2 - 24. Sanitärtechnisches Symposium
CY - Ahaus, Germany
DA - 04.04.2025
KW - Korrosion
KW - Metallmigration
KW - Trinkwasser
PY - 2025
AN - OPUS4-62900
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stephan-Scherb, Christiane
T1 - Effect of a mixed atmosphere H2O-O2-SO2 on the oxidation kinetics and phase formation on CrMnFeCoNi and CrCoNi
N2 - The high-entropy alloy (HEA) CrMnFeCoNi and the medium-entropy alloy (MEA) CrCoNi with a face-centered cubic (fcc) structure have excellent mechanical properties and are considered for high-temperature applications. Both materials were exposed under several oxidized atmospheres in a wide temperature range/regime. Mn-oxide (Mn3O4, Mn2O3) was mainly formed on the HEA and Cr2O3 on the MEA. The fast diffusion of manganese prevents the formation of a continuous chromia layer on CrMnFeCoNi in Ar-O2, Ar-H2O and Ar-SO2 at 800°C.
The Cantor alloy and his ternary subsystem CrCoNi were exposed in Ar-O2-H2O-SO2 at 800°C up to 96 h to clarify their oxidation behavior in a mixed atmosphere. The oxidized samples were analyzed by weight measurement, scanning electron microscopy (SEM), and X-ray diffraction analysis (XRD). It was found that mass gain of all samples increased with increasing exposure time. The oxidation rate of the Cantor alloy is significantly higher than that of the ternary alloy system.
T2 - International Conference on High Entropy Materials
CY - Berlin, Germany
DA - 27.09.2020
KW - High Entropy Alloys
KW - Medium Entropy Alloys
KW - High temperature corrosion
KW - Oxidation
KW - Sulfidation
PY - 2020
AN - OPUS4-51488
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wagner, Adrian
T1 - Korrosionsmonitoring bei der Instandsetzung von chloridbelasteten Stahlbetonwerken (KOMICS)
N2 - In der aktuellen RL-SIB wie auch im Gelbdruck der Instandhaltungsrichtlinie ist bei Anwendung des Instandsetzungsprinzips W-Cl bzw. Verfahren 8.3 der Erfolg der Maßnahme durch Einbau und Messung von Korrosionsstrom-Mess-Einrichtungen nachzuweisen. Auch wird bei der Instandsetzung von chloridbelasteten Rissen bei Stahlbetonbauteilen durch Verpressen der Risse bzw. Aufbringen einer Rissbandage ein Korrosionsmonitoring empfohlen. Anerkannte Regelwerke oder Normen über Art und Aufbau des Monitoring-Systems sowie Kriterien zur Bewertung der Messergebnisse im Hinblick auf den Erfolg der Instandsetzungsmaßnahme gibt es derzeit nicht. Auch sind keine Untersuchungen zur Qualität der Messergebnisse veröffentlicht. Ziel des Vorhabens ist die Ausarbeitung eines Regelwerks-Entwurfes für die Art und den Aufbau von Korrosionsmonitoring-Systemen sowie für Kriterien zur zuverlässigen Bewertung der Messergebnisse, mit denen der Erfolg bei folgenden Instandsetzungskonzepten überprüft werden kann.
T2 - 15. Sitzung des NA 062-01-77 AA "Korrosionsprüfverfahren"
CY - Online meeting
DA - 28.10.2020
KW - Korrosionsmonitoring
KW - Korrosion
KW - Korrosionssensoren
KW - Chloridinduzierte Lochkorrosion
KW - W-Cl Instandsetzungsprinzip
PY - 2020
AN - OPUS4-51520
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Standard Operating Procedures in the digital context
N2 - The intention of the presentation is to inspire a discussion on the needs and challenges for the digitalisation of SOPs. SOPs are available for the disciplines of physical-chemical characterisation, for toxicology, for environmental applications and for exposure applications. Furthermore the SOPs need to be integrated in the regulatory framework and need to be detailed enough for the digital processing. This is highlighted in this presentation.
T2 - Nanosafety 2020
CY - Online meeting
DA - 07.10.2020
KW - Nano
KW - SOP
KW - NFDI
KW - Digitalisation
KW - Operating Procedure
PY - 2020
AN - OPUS4-51491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Klinger, Christian
T1 - Systematische Schadensanalyse: Vergleich und Anwendung von Richtlinien und Prozeduren
N2 - Recherche verschiedener jeweils nationaler/internationaler Regelwerke
und Prozeduren für die Systematische Schadensanalyse
• Literaturrecherche zu Methoden der systematischen interdisziplinären Schadensanalyse
• Vergleich der Regelwerke VDI 3822, ASTM, ASM sowie der Methoden
• Anwendung der Regelwerke/Prozeduren und Methoden am Beispiel
T2 - 46. VDI Jahrestagung: Schadensanalyse in der Energietechnik
CY - Online meeting
DA - 06.10.2020
KW - Regelwerke
KW - Systematische Schadensanalysen, Prozeduren
PY - 2020
AN - OPUS4-51401
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Wie gehe ich bei einer Schadensuntersuchung vor?
N2 - Die Vorgehensweise bei einer Schadensanalyse wird beschrieben. Hinweise zu Methodik, Fehlervermeidung und Verhalten werden gegeben.
T2 - Der sichere Einsatz von Werkstoffen aus Kupfer und Kupferlegierungen in der Trinkwasserinstallation
CY - Online meeting
DA - 21.10.2020
KW - Schadnesanalyse
KW - Vorgehensweise
KW - Korrosion
PY - 2020
AN - OPUS4-51453
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
T1 - Wenn es im Holz knackt. Über die Herausforderung, kritische Versagensvorgänge in Holzstrukturen mittels Schallemissionsanalyse zu identifizieren
N2 - Um die Versagensabläufe über die verschiedenen Skalen im Holzwerkstoff verfolgen zu können, werden Zugversuche an Lagenhölzern mittels Schallemissionsmessung überwacht. Synchron erfolgen In-situ-Messungen mit Digitaler Bildkorrelation bzw. Synchrotron-Mikro-Computertomographie. Die Kombination aller Ergebnisse wie auch die Anwendung der frequenzbasierten Mustererkennung und die Simulation ausgewählter Versuche zielen auf die Identifizierung zugrunde liegender Mechanismen hin. Abschließend werden Ansätze für ein Monitoring von Holzstrukturen diskutiert.
T2 - 419. Sitzung AK Berlin der DGZFP
CY - Online meeting
DA - 15.09.2020
KW - Acoustic Emission (AE)
KW - Holzwerkstoffe
KW - Mustererkennung
KW - Monitoring Konzept
PY - 2020
AN - OPUS4-51361
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Corrosion Problems with 1.4521 steel pipes in drinking water
N2 - In several cases crevice corrosion with 1.4521 stainless steel pipes was observed. The presentation shows the investigations that lead to the solution of the failure cases
T2 - Eurocorr 2020
CY - Online meeting
DA - 07.09.2020
KW - Crevice corrosion
KW - Drinking water
KW - Stainless steel
KW - Failure analysis
PY - 2020
AN - OPUS4-51235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Everything and the kitchen sink: correcting X-ray data for everything
N2 - Recorded at the Better with Scattering workshop 2020, this talk highlights the complete set of data correction steps that we do for the MAUS, and how they can be used elsewhere too. This links well with the talk in this series by Dr. Tim Snow, and also highlights the details of the background subtraction that needs to be done.
T2 - Better with Scattering workshop 2020
CY - BAM, Berlin, Germany
DA - 16.03.2020
KW - Small angle scattering
KW - Data corrections
PY - 2020
UR - https://www.youtube.com/watch?v=Hp4qziOxZFk
AN - OPUS4-51018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Auslagerungsversuche von Standardproben nach DIN EN ISO 9223 unter verschiedenen atmosphärischen Bedingungen
N2 - Der Vortrag berichtet über die Auslagerung von Standardproben nach DIN EN ISO 9223 bis 9226 aus Zink, Stahl, Kupfer und Aluminium auf den verschiedenen atmosphärischen Bewitterungsständen der Bundesanstalt für Materialforschung und -prüfung (BAM). Im Vortrag werden die Masseverluste, Korrosionsgeschwindigkeiten und Korrosivitätskategorien der Standardproben im freibewitterten und überdachten Bereich nach einem Jahr vorgestellt und Unterschiede hinsichtlich der Atmosphärenbedingungen aufgezeigt. Freibewitterte Proben zeigen dabei deutliche Unterschiede hinsichtlich ihres Korrosionsverhaltens im Vergleich zu überdachten Proben. Die ermittelten Korrosivitätskategorien sind sowohl standort- als auch materialspezifisch.
T2 - Gemeinsame Sitzung des GfKORR Arbeitskreises „Korrosionsschutz von Windenergieanlagen“ mit der Fachgruppe „Korrosionsschutz“ der WAB e.V.
CY - Online meeting
DA - 07.12.2020
KW - Atmosphärische Korrosion
KW - Auslagerungsversuche
KW - Freibewitterung
KW - Korrosion
PY - 2020
AN - OPUS4-51783
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voigt, Marieke
A1 - Gardei, Andre
A1 - Meng, Birgit
ED - di Prisco, M.
ED - Meda, A.
ED - Balazs, G.L.
T1 - The adaption of the set-up for gas permeability measurements for ultra-high performance concrete
N2 - In the framework of this project, a steam pressure vessel was to be developed from ultra-high perfor-mance concrete (UHPC) to withstand process temperatures of 200 °C and the respective steam pressure of 15,5 bar. To guarantee the long-term water vapour tightness of the system, the permeability of two UHPC mixtures were tested after long-term cyclic autoclaving. As UPHC shows a high density and therefore low permeability, measurements after the RILEM-Recommendation (TC 116-PCD) reached their detection limit. Therefore, the measurement set-up was adapted to measure the permeability of highly dense UHPC more reliably and quickly. This adaption includes measurements in a higher pres-sure range, the change of sample size thickness and the usage of Ar as a medium compared with the RILEM Recommendation. Additionally, the system was equipped with two pressure sensors and Ar-flowmeters to guarantee a continuous record of the experimental parameters. The new system was tested and evaluated by comparing measurements with the RILEM recommended system. Preliminary results show that the adapted system is capable to provide efficient and reliable results of concrete with low permeability.
T2 - 14th fib PhD Symposium in Civil Engineering
CY - Rom, Italy
DA - 05.09.2022
KW - Durability
KW - UHPC
KW - gas permeability
PY - 2022
SN - 978-2-940643-17-2
SN - 2617-4820
VL - 58
SP - 353
EP - 359
AN - OPUS4-56862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stohl, Leonie
T1 - Bioreceptivity of structured concrete panels
N2 - Understanding the fundamentals of bioreceptivity enables the developement of functionalized materials. Concrete as the most used building material worldwide is of special interest as microbially greened panels may represent an alternative to classic façade greening with plants. � This project includes extensive outdoor experiments, in which eight differently structured concrete panels are weathered under different conditions, aiming to grow a stable biofilm of photosynthetic eukaryotic organisms. Documentation and data analysis of this experiment will be demonstrated using an example of one of the surfaces.
T2 - Word Green Infrastructure Congress 2023
CY - Berlin, Germany
DA - 27.06.2023
KW - Bioreceptivity
KW - Concrete
KW - Material design
PY - 2023
AN - OPUS4-57919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Brinkmann, M.
A1 - Wiehle, Philipp
A1 - Thiele, Marc
A1 - Graubner, C.-A.
ED - Schermer, D.
ED - Brehm, E.
T1 - Grundlagen zur Bemessung druckbeanspruchten Lehmmauerwerks
N2 - Lehmmauerwerk bietet sich aufgrund seiner zahlreichen ökologischen Vorteile für die Errichtung klimafreundlicher und ressourcenschonender Gebäude an. Um den Anwendungsbereich tragenden Lehmmauerwerks durch eine zeitgemäße Nachweisführung zu erweitern, werden in diesem Beitrag Grundlagen für die Entwicklung eines eurocodekonformen Bemessungskonzepts erarbeitet. Hierzu werden die Ergebnisse umfangreicher experimenteller Untersuchungen an Lehmmauerwerk sowie Lehmsteinen und -mörteln nach Konditionierung bei unterschiedlichen Klimata vorgestellt. Darauf aufbauend erfolgt eine Traglastanalyse druckbeanspruchter Lehmmauerwerkswände mittels numerischer und analytischer Methoden. Die daraus gewonnenen Erkenntnisse werden abschließend in einen an DIN~EN~1996-3/NA angelehnten Bemessungsvorschlag überführt, welcher die materialspezifischen Besonderheiten von Lehmmauerwerk berücksichtigt und eine fundierte Grundlage für eine wirtschaftliche und zuverlässige Nachweisführung darstellt.
KW - Druckfestigkeit
KW - Lehm
KW - Mauerwerk
KW - Bemessung
KW - Feuchte
PY - 2023
SN - 978-3-433-03373-9
DO - https://doi.org/10.1002/9783433611142.ch4
VL - 48
SP - 79
EP - 110
PB - Ernst & Sohn GmbH
CY - Berlin
ET - 1
AN - OPUS4-57509
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Strobl, Domninic
T1 - PGD in thermal transient problems with a moving heat source – a sensitivity study on factors affecting accuracy and efficiency
N2 - Thermal transient problems, essential in applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting the application, e. g. for model parameter estimation or online process control. Model order reduction, a solution to preserve accuracy while reducing complexity, is explored. This paper addresses challenges in developing a reduced model using the Proper Generalized Decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model's performance and emphasize the importance of their consideration when implementing such models. For thermal examples it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model.
KW - Additive manufacturing
KW - Mapping for unseparable load
KW - Model order reduction
KW - Proper generalized decomposition
KW - Sensitivity analysis
KW - Thermal transient problem
PY - 2024
DO - https://doi.org/10.5281/zenodo.10102489
PB - Zenodo
CY - Geneva
AN - OPUS4-62235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manninger, T.
A1 - von Werder, Julia
A1 - Rübner, Katrin
T1 - Lehmstabilisierung mittels eines Biomasseasche basierten Alkali-Aktivators und kalziniertem Ton
N2 - Lehm sowie Lehmziegel sind jahrtausendealte Baustoffe, die sich durch lokale Verfügbarkeit, Umweltverträglichkeit und geringe COa-Belastung auszeichnen.
Diese Eigenschaften machen sie zu Baustoffen der Zukunft. Wasserbeständigkeit ist ein wichtiger Aspekt, der beim Einsatz beachtet werden muss. Es gibt verschiedene Ansätze zur Stabilisierung, Idealerwelse sollen dabei die positiven Aspekte des Lehms, wie beispielsweise die Luftfeuchteregullerung, bewahrt werden. Zement ist hierfür nur bedingt geeignet.
Als Alternative zur Stabilisierung mit Zement wurden in einer Versuchsreihe Mischungen mit calclnierten Tonen untersucht. Diese bei 600 °C auf CO2 sparende Welse erzeugten, lokal verfügbaren Rohstoffe, können mittels Alkall-Aktivierung zu einem festen „Geopolymer" vernetzt werden. Zur Aktivierung wurde eine lokal verfügbare Biomasseasche aus Hackschnitzelholz, sowie Industriell hergestelltes KOH genutzt, da das in beiden enthaltene Kalium das umweltverträglichste Alkallion Ist.
In einer Versuchsreihe wurde das Verhalten des reinen Lehms mit dem stabilisierten Material verglichen. Es wurden Festigkeitswerte, Wasserlagerungsbeständigkeit und Wasserdampfdiffusionswiderstand geprüft.
T2 - Internationale Baustofftagung (ibausil)
CY - Weimar, Germany
DA - 13.09.2023
KW - Lehmstabilisierung
KW - Alkali aktivierte Bindemittel
KW - Wasserbeständigkeit
KW - Putz
KW - Erdbau
KW - Kalzinierter Ton
PY - 2023
UR - https://www.uni-weimar.de/de/bauingenieurwesen/institute/fib/ibausil/
VL - 2023
SP - 1
EP - 6
PB - Sonderausgabe des Online-Journals ce/papers von Wiley
AN - OPUS4-58316
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spilker, A.
A1 - Stelzner, Ludwig
A1 - Weise, Frank
A1 - Wieland, M.
T1 - Analyse der thermischen Dehnung von Fahrbahndeckenbetonen aus dem BAB-Netz
N2 - Die Kenntnis von Materialeigenschaften spielt bei der Entwicklung oder Optimierung von Betonen und Bauweisen für den Straßenbau sowie der Qualitätssicherung eine bedeutende Rolle. Gleichermaßen bilden physikalische Materialkennwerte die Grundlage für die rechnerische Dimensionierung und die Restsubstanzbewertung von Betonfahrbahndecken. Eine relevante Kenngröße bei der Untersuchung thermisch induzierter Spannungs- und Verformungszustände stellt der thermische Ausdehnungskoeffizient dar. Im Zuge der systematischen Weiterentwicklung der rechnerischen Dimensionierung, aber auch im Zusammenhang mit der gezielten Verbesserung der Gebrauchseigenschaften von Betonfahrbahndecken gilt es zu hinterfragen, ob lastunabhängige Formänderungseigenschaften der verwendeten Betone aktuell ausreichend Beachtung finden, ob allgemeine Literaturwerte für die heutigen Fahrbandeckenbetone stets Gültigkeit besitzen und ob deren Implementierung in numerische Modelle zu realitätsnahen Vorhersagen führt. Für eine empirische Herangehensweise ist die Verfügbarkeit adäquater Prüfverfahren von entscheidender Bedeutung. In Deutschland existiert aktuell jedoch kein standardisiertes oder genormtes Verfahren für die prüftechnische Bestimmung des thermischen Ausdehnungskoeffizienten von Beton. Daher wurden unter Beachtung straßenbauspezifischer Gesichtspunkte zwei Prüfansätze entwickelt, die in diesem Beitrag vorgestellt sowie hinsichtlich möglicher Messunsicherheiten und Messungenauigkeiten diskutiert werden. Außerdem werden ausgewählte Ergebnisse aus Analysen an Bestandsbetonen aus dem BAB-Netz dargestellt. Im Ergebnis sollen die Untersuchungen einen Beitrag zur Schaffung der prüftechnischen Voraussetzungen für eine abgesicherte Quantifzierung der thermischen Dehnung von Fahrbahndeckenbetonen leisten.
KW - Betonfahrbahndecken
KW - Materialkennwerte
KW - Thermischer Ausdehnungkoeffizient
KW - Prüfverfahren
PY - 2020
DO - https://doi.org/10.1002/best.202000044
VL - 116
IS - 1
SP - 26
EP - 34
PB - John Wiley & Sons
AN - OPUS4-54967
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
T1 - Amts- und Mitteilungsblatt, Band 53, Heft 2
T3 - Amts- und Mitteilungsblatt der BAM - 2/2023
KW - Anerkennungen
KW - Zulassungen
KW - Richtlinien
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577330
SN - 0340-7551
VL - 53
IS - 2
SP - 341
EP - 462
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-57733
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Probing laser-driven structure formation at extreme scales in space and time
N2 - Irradiation of solid surfaces with intense ultrashort laser pulses represents a unique way of depositing energy into materials. It allows to realize states of extreme electronic excitation and/or very high temperature and pressure and to drive materials close to and beyond fundamental stability limits. As a consequence, structural changes and phase transitions often occur along unusual pathways and under strongly nonequilibrium conditions. Due to the inherent multiscale nature — both temporally and spatially—of these irreversible processes, their direct experimental observation requires techniques that combine high temporal resolution with the appropriate spatial resolution and the capability to obtain good quality data on a single pulse/event basis. In this respect, fourth-generation light sources, namely, short wavelength and short pulse free electron lasers (FELs), are offering new and fascinating possibilities. As an example, this talk will discuss the results of scattering experiments carried out at the FLASH free electron laser at DESY (Hamburg, Germany), which allowed us to resolve laser-induced structure formation at surfaces on the nanometer to submicron length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution. The current status and future perspectives in this field via exploiting the unique possibilities of these 4th-generation light sources will be discussed.
T2 - Seminar, Instituto de Óptica, CSIC
CY - Madrid, Spain
DA - 05.10.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Free electron laser (FEL)
KW - Time-resolved scattering
KW - Capillary waves
PY - 2023
AN - OPUS4-58517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
T1 - Bewertung der Innenhydrophobierung als neuartige AKR-Vermeidungsstrategie bei Betonfahrbahndecken
N2 - Zur Vermeidung von AKR-Schäden an Betonfahrbahndecken im deutschen Autobahnnetz wurden mit dem ARS 04/2013 verbindliche Eignungsprüfungen zum Ausschluss alkaliempfindlicher Gesteinskörnungen bei Neubau- und Erhaltungsmaßnahmen eingeführt. Das hatte eine signifikante Reduzierung geeigneter Gesteinskörnungen zur Folge. Deshalb wird geprüft, ob durch die Zugabe eines Hydrophobierungsmittels während der Betonherstellung grenzwertig alkaliempfindliche Gesteinskörnungen nutzbar gemacht werden können. In diesem Beitrag wird der Einfluss der Dosierung eines Compounds mit Hydrophobierungsmittel (HM) auf die Frisch- und Festbetoneigenschaften eines Waschbetons mit einer reaktiven Grauwacke dargestellt. Es zeigt sich, dass aufgrund des Antagonismus die zunehmende Dosierung des HM-Compounds eine signifikante Erhöhung der Zugabe des Luftporenbildners auf Wurzelharzbasis erfordert. Der AKR-Schädigungsprozess wird ab einer Dosierung des HM-Compounds von 0,75 M.-%, bezogen auf den Zementgehalt, hinreichend vermindert. Die mechanischen Eigenschaften des hydrophobierten Waschbetons verschlechtern sich im betrachteten Dosierungsbereich des HM-Compounds nur geringfügig. Auch der Frost-Tausalz-Widerstand vermindert sich, ohne den normativen Grenzwert für die Abwitterung zu überschreiten.
T2 - 21. Internationale Baustofftagung ibausil
CY - Weimar
DA - 13.09.2023
KW - Alkali-Kieselsäure-Reaktion
KW - Betonfahrbahndecke
KW - Innenhydrophobierung
KW - AKR-Vermeidung
PY - 2023
AN - OPUS4-58357
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spaltmann, Dirk
T1 - Improvement of the tribological performance of titanium alloy using FS-laser-induced periodic surface structures in combination with ZDDP and ionic liquid lubricant additives
N2 - The performance of titanium alloy (Ti6Al4V) surfaces was investigated in lubricated reciprocating sliding tribological tests (RSTT). Special emphasis was laid on the effect of surface nanostructures in area of contact on the respective friction and wear behaviour. These so-called laser-induced periodic surface structures (LIPSS, ripples) were produced on the titanium alloy surface upon scan processing in air by an ultrashort pulsed femtosecond (fs) laser. As lubricant served two types of base oils, a pure polyalcylene-glycol, and an SAE 0W30 oil containing only antioxidants and temperature stabilizers. Tribological tests were carried out on polished as well as LIPSS covered areas using both types of base oil. A test metrics was established, combining the additive 2-ethylhexyl-zincdithiophosphate (ZDDP) or the ionic liquid [P6,6,6,14] [DEHP] (98% purity) with the respective base oils. The test metrics also considered the orientation of motion with respect to the orientation of the structures formed on the surface. Results are presented which show that the interplay between LIPSS and the local chemistry formed by the respective additives is beneficial for the tribological behaviour of the titanium alloy. Certain combinations of base oil, additive and LIPSS reduced friction and wear significantly in the tribological contact.
T2 - 64. Tribologie-Fachtagung
CY - Göttingen, Germany
DA - 25.09.2023
KW - TiAl64V
KW - 100Cr6
KW - Friction
KW - Wear
KW - LIPSS
KW - Lubrication
KW - PAG
KW - Ionic liquid
PY - 2023
AN - OPUS4-58641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - "Grabenkorrosion": How scientific debate leads to an solution. And modern failures due to neglection of well described facts
N2 - In the late 1980s, a new type of corrosion appeared in drinking water installations where galvanized steel pipes failed forming a deep groove with no corrosion at the other surfaces. The reason was discussed quite fiercely between failure analysts and material suppliers. In the end the discussion lead to the solution: inductive welded pipes of a certain sulphur content were prone to selective corrosion. The history of the arguments is discussed using old communications between Wilhelm Schwenk and Wolfgang Stichel, who later published the results in a paper unfortunately only I german.
Thus the knowledge got lost and new cases based on the same material problems are observed in application of so-called C-Steel piping systems. Failure cases are shown.
T2 - MTech 2023
CY - Cavtat, Croatia
DA - 02.10.2023
KW - Corrosion
KW - Grabenkorrosion
PY - 2023
AN - OPUS4-58518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Milks, A.
A1 - Lehmann, J.
A1 - Leder, D.
A1 - Sietz, M.
A1 - Koddenberg, T.
A1 - Böhner, U.
A1 - Wachtendorf, Volker
A1 - Terberger, T.
T1 - A double-pointed wooden throwing stick from Schöningen, Germany: Results and new insights from a multianalytical study
N2 - The site of Schöningen (Germany), dated to ca. 300,000 years ago, yielded the earliest large-scale record of humanly-made wooden tools. These include wooden spears and shorter double-pointed sticks, discovered in association with herbivores that were hunted and butchered along a lakeshore. Wooden tools have not been systematically analysed to the same standard as other Palaeolithic technologies, such as lithic or bone tools. Our multianalytical study includes micro-CT scanning, 3-dimensional microscopy, and Fourier transform infrared spectroscopy, supporting a systematic technological and taphonomic analysis, thus setting a new standard for wooden tool analysis. In illustrating the biography of one of Schöningen’s double-pointed sticks, we demonstrate new human behaviours for this time period, including sophisticated woodworking techniques. The hominins selected a spruce branch which they then debarked and shaped into an aerodynamic and ergonomic tool. They likely seasoned the wood to avoid cracking and warping. After a long period of use, it was probably lost while hunting, and was then rapidly buried in mud. Taphonomic alterations include damage from trampling, fungal attack, root damage and compression. Through our detailed analysis we show that Middle Pleistocene humans had a rich awareness of raw material properties, and possessed sophisticated woodworking skills. Alongside new detailed morphometrics of the object, an ethnographic review supports a primary function as a throwing stick for hunting, indicating potential hunting strategies and social contexts including for communal hunts involving children. The Schöningen throwing sticks may have been used to strategically disadvantage larger ungulates, potentially from distances of up to 30 metres. They also demonstrate that the hominins were technologically capable of capturing smaller fast prey and avian fauna, a behaviour evidenced at contemporaneous Middle Pleistocene archaeological sites.
KW - FTIR
KW - Stone Age
KW - Middle Pleistocene
KW - Throwing-stick
KW - Wood
KW - Micro-CT scanning
KW - 3-dimensional microscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580012
DO - https://doi.org/10.1371/journal.pone.0287719
SN - 1932-6203
VL - 18
IS - 7
SP - 1
EP - 32
PB - PLOS
CY - San Francisco, California, US
AN - OPUS4-58001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pirker, F.
A1 - Toth, I.
A1 - Cihak-Bayr, U.
A1 - Grundtner, R.
A1 - Vernes, A.
A1 - Benedicto, J.
A1 - Spaltmann, Dirk
A1 - Gradt, Thomas
A1 - Alberdi, A.
A1 - Alonso, I.
A1 - Bayón, R.
A1 - Igartua, A.
A1 - García, Á.
A1 - Pagano, F.
A1 - Bravo, I.
A1 - Kogia, M.
A1 - Dykeman, D.
A1 - Liedtke, S.
A1 - Minami, I.
A1 - Nyberg, E.
A1 - Soivio, K.
A1 - Ronkainen, H.
A1 - Majaniemi, S.
A1 - Heino, V.
A1 - Gkagkas, K.
A1 - Mont, L.
A1 - Amigorena, I.
T1 - Tribological characterisation services for materials - i-TRIBOMAT
N2 - Um den Entwicklungsprozess von neuen Komponenten zu beschleunigen, ist die Vorrausage der Eigenschaften der eingesetzten Werkstoffe im Betrieb der Komponenten von enormer Bedeutung. Um neue Werkstoffe hinsichtlich Ihrer Performance (in einer Komponente) bewerten zu können, ist deshalb die Entwicklung neuer innovativer Methoden notwendig. Diese Methoden können auch unter dem Begriff „lab-to-field“ oder „materials“ – up-scaling zusammengefasst werden. D. h. Werkstoffe werden im Labor charakterisiert, und deren Eigenschaften mittels z.B. Simulation auf die Komponentenperformance hochskaliert (upscaling). i-TRIBOMAT ist ein EU gefördertes Projekt (H2020, GA Nr. 814494) mit dem Ziel ein Open Innovation Test Bed für tribologische Werkstoffcharakterisierung aufzubauen und entsprechende Services von der tribologischen Charakterisierung neuer Werkstoffe bis hin zu Simulationsmodellen zur Vorrausage der Perfomance von Komponenten der Industrie anzubieten. Durch die Bündelung von Knowhow und Infrastruktur zu Charakterisierung sowie den Aufbau einer digitalen Plattform, wird i-TRIBOMAT das weltgrößte Open Innovation Test Bed für tribologische Werkstoffcharakterisierung.
N2 - The prediction of the properties of the materials used in the operation of components is of enormous importance, in order to accelerate the development process of new components. To evaluate new materials in terms of their performance (in a component), the development of new innovative methods is necessary. These methods can also be summarized under the term lab-to-field or materials – upscaling, meaning materials being characterised in a laboratory and their properties being upscaled to the component performance by means of e.g. simulation. i-TRIBOMAT is a EU funded project (H2020, GA Nr. 814494) aiming at building an Open Innovation Test Bed for tribological material characterization and offering corresponding services from tribological characterization of new materials to simulation models for predicting the performance of industrial components. By bundling the infrastructure, know-how for characterization and building a digital platform, i-TRIBOMAT becomes the world’s largest open innovation test bed for tribological material characterization.
T2 - 22nd International Colloquium Tribology
CY - Esslingen, Germany
DA - 28.01.2020
KW - Tribologie
KW - Lab-to-field up-scaling
KW - Werkstoffdatenbank
KW - Geteilte Infrastruktur
KW - Tribo-Analytik
KW - Intelligente tribologische Werkstoffcharakterisierung
KW - Lab-to-field upscaling
KW - Tribology
KW - Intelligent tribological material characterization
KW - Materials database
KW - Shared infrastruture
KW - Tribo-analytics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576762
DO - https://doi.org/10.30419/TuS-2020-0026
SN - 0724-3472
SN - 2941-0908
VL - 67
IS - 5-6
SP - 35
EP - 50
PB - Expert
CY - Tübingen
AN - OPUS4-57676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Einführung in die Korrosion metallener Werkstoffe
N2 - Im Vortrag werden die wesentlichen Grundlagen zum Verständnis der Korrosion metallener Werkstoffe in komprimierter Form vorgestellt. Der Schwerpunkt liegt auf der Betrachtung der atmosphärischen Korrosion und den sich daraus ergebenden Anforderungen an den Korrosionsschutz insbesondere für den Bereich Verpackungen.
T2 - CORPAC Seminar: Wie lassen sich VCI-Korrosionsschutz und Nachhaltigkeit vereinbaren?
CY - Weidhausen bei Coburg/Germany
DA - 29.03.2023
KW - Atmosphärische Korrosion
KW - Einflussparameter
KW - Befeuchtungsdauer
PY - 2023
AN - OPUS4-57250
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hering, Marcus
A1 - Sievers, Jürgen
A1 - Curbach, Manfred
A1 - Beckmann, Birgit
T1 - An Approach to Predicting the Ballistic Limit of Thin Textile-Reinforced Concrete Plates Based on Experimental Results
N2 - In this article, a partial selection of experiments on enhancing the impact resistance of structural components with non-metallic, textile-reinforced concrete is discussed. The focus is on the experimental investigations in which the impact resistance of thin, textile-reinforced concrete plates is characterized. The article discusses the materials, fabrics and test setup used. For the experimental work, a drop tower from the Otto Mohr Laboratory, which belongs to the Technische Universtät Dresden, was used. Furthermore, the experimental results are presented and evaluated using different methods. Based on the collected data, a suitable approach to determining the perforation velocity of an impactor through the investigated thin, textile-reinforced concrete plates is shown.
KW - Building and Construction
KW - Civil and Structural Engineering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586692
DO - https://doi.org/10.3390/buildings13092234
VL - 13
IS - 9
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-58669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weichert, D.
T1 - Robustness in Fatigue Strength Estimation
N2 - Fatigue strength estimation is a costly manual material characterization process in which state-of-the-art approaches follow a standardized experiment and analysis procedure. In this paper, we examine a modular, Machine Learning-based approach for fatigue strength estimation that is likely to reduce the number of experiments and, thus, the overall experimental costs. Despite its high potential, deployment of a new approach in a real-life lab requires more than the theoretical definition and simulation. Therefore, we study the robustness of the approach against misspecification of the prior and discretization of the specified loads. We identify its applicability and its advantageous behavior over the state-of-the-art methods, potentially reducing the number of costly experiment.
T2 - 2nd Annual AAAI Workshop on AI to Accelerate Science and Engineering
CY - Washington DC, USA
DA - 07.02.2023
KW - Active Learning
KW - Gaussian Process
KW - Fatigue Strength
PY - 2022
AN - OPUS4-56684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andrade, C.
A1 - Saucedo, L.
A1 - Rebolledo, N.
A1 - Cabeza, S.
A1 - Meinel, Dietmar
T1 - X-Ray computed tomography and traditional analysis of a capillary absorption test in cement pastes
N2 - Water absorption testing has the attraction of being simple, relatively quick and use water as a fluid which is the key substance in the possible concrete deterioration. However, in spite of the advantages its application has remained empirical, except for the testing of resistance to frost, through the identification of the critical degree of saturation. Rilem TC-116 studied this test, among others, for the characterization of concrete resistance against transport through the concrete pore network. Results indicated a low discriminating ability of the absorbency for qualifying concrete resistance and then, it seemed necessary to try to move forward by making the link between the absorption testing and the concrete pore microstructure. In the present work, thanks to the X-Ray computed tomography, it is described the evolution of the water front in three paste-specimen with different w/c ratios (different pore radius distributions). The observations allowed us to deduce that all the pores start to fill simultaneously, but the bigger ones fill quicker and rise less. The saturation degree is measured along the height of the sample, showing that each pore size has a different rate which becomes constant after the first hour. Washburn’s equation was applied to the progressive advance of the water front, resulting in a pore radius much smaller than the one expected.
KW - Capillary absorption
KW - Pore size distribution
KW - X-ray CT
KW - Gravimetry
PY - 2020
DO - https://doi.org/10.1016/j.cemconcomp.2020.103634
VL - 113
SP - 103634
PB - Elsevier Ltd.
CY - London
AN - OPUS4-51487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brockmann, N.
A1 - Sicken, A.
A1 - Krüger, Jörg
T1 - Effects of laser cleaning on the condition of different silk model samples using varying wavelengths and pulse durations
N2 - The cleaning of aged silk fibers poses a common challenge in the conservation of textiles, since traditional cleaning techniques often yield unsatisfactory results or even harm objects. In this regard, cleaning objects with laser radiation is a promising addition to the range of available methods. Due to it being contactless, even brittle and touch-sensitive objects with disfiguring or harmful soiling could potentially be cleaned and therefore made accessible for research and presentation. Examples of treatment have sometimes shown spectacular results. Still there is some skepticism concerning the safety of this treatment for textile materials, which has been strengthened through previous 532 nm wavelength nanosecond laser cleaning studies on silk fibers. Taking these published results into account, the range of examined laser parameters has been extended in this study, from 532 nm nanosecond laser to 1064 nm nanosecond and even 800 nm femtosecond laser, reevaluating the effect of this treatment on the fibers. The physicochemical processes taking place on the silk fibers when cleaning with lasers are complex and still not fully understood. The aim of this project was therefore to bring more clarification about potential effects of those processes on the condition of silk samples treated with a set of different parameters for wavelength, pulse duration, energy density and number of pulses per spot. It also looks at the influence of the presence of soiling on the results. The analysis of potential effects was then carried out using statistical methods and advanced analytics. Scanning electron microscopy, Fourier-transform infrared spectroscopy and colorimetry technology provided the required insights to better assess the effects. Results show that laser cleaning of silk fibers, like most other conventional cleaning techniques, is not completely without risk, but knowing what the possible effects are helps making decisions on whether the benefits of the technique used justify these risks.
KW - Laser cleaning
KW - Cultural heritage
KW - Conservation
KW - Silk
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594601
DO - https://doi.org/10.1186/s40494-024-01152-1
SN - 2050-7445
VL - 12
IS - 1
SP - 1
EP - 15
PB - Springer
AN - OPUS4-59460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Was, G.S.
A1 - Bahn, C.-B.
A1 - Busby, J.
A1 - Cui, B.
A1 - Farkas, D.
A1 - Gussev, M.
A1 - Rigen He, M.
A1 - Hesterberg, J.
A1 - Jiao, Z.
A1 - Johnson, D.
A1 - Kuang, W.
A1 - McMurtrey, M.
A1 - Robertson, I.
A1 - Sinjlawi, A.
A1 - Song, M.
A1 - Stephenson, K.
A1 - Sun, K.
A1 - Swaminathan, Srinivasan
A1 - Wang, M.
A1 - West, E.
T1 - How irradiation promotes intergranular stress corrosion crack initiation
N2 - Irradiation assisted stress corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide.
KW - Irradiation
KW - Stress corrosion cracking
KW - Grain boundaries
KW - Oxidation
KW - Austenitic alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595748
DO - https://doi.org/10.1016/j.pmatsci.2024.101255
SN - 0079-6425
VL - 143
SP - 1
EP - 15
PB - Elsevier
AN - OPUS4-59574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Minenkov, Alexey
A1 - Hollweger, Sophia
A1 - Duchoslav, Jiri
A1 - Erdene-Ochir, Otgonbayar
A1 - Weise, Matthias
A1 - Ermilova, Elena
A1 - Hertwig, Andreas
A1 - Schiek, Manuela
T1 - Monitoring the Electrochemical Failure of Indium Tin Oxide Electrodes via Operando Ellipsometry Complemented by Electron Microscopy and Spectroscopy
N2 - Transparent conductive oxides such as indium tin oxide (ITO) are standards for thin film electrodes, providing a synergy of high optical transparency and electrical conductivity. In an electrolytic environment, the determination of an inert electrochemical potential window is crucial to maintain a stable material performance during device operation. We introduce operando ellipsometry, combining cyclic voltammetry (CV) with spectroscopic ellipsometry, as a versatile tool to monitor the evolution of both complete optical (i.e., complex refractive index) and electrical properties under wet electrochemical operational conditions. In particular, we trace the degradation of ITO electrodes caused by electrochemical reduction in a pH-neutral, water-based electrolyte environment during electrochemical cycling. With the onset of hydrogen evolution at negative bias voltages, indium and tin are irreversibly reduced to the metallic state, causing an advancing darkening, i.e., a gradual loss of transparency, with every CV cycle, while the conductivity is mostly conserved over multiple CV cycles. Post-operando analysis reveals the reductive (loss of oxygen) formation of metallic nanodroplets on the surface. The reductive disruption of the ITO electrode happens at the solid–liquid interface and proceeds gradually from the surface to the bottom of the layer, which is evidenced by cross-sectional transmission electron microscopy imaging and complemented by energy-dispersive X-ray spectroscopy mapping. As long as a continuous part of the ITO layer remains at the bottom, the conductivity is largely retained, allowing repeated CV cycling. We consider operando ellipsometry a sensitive and nondestructive tool to monitor early stage material and property changes, either by tracing failure points, controlling intentional processes, or for sensing purposes, making it suitable for various research fields involving solid–liquid interfaces and electrochemical activity.
KW - General Materials Science
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597625
DO - https://doi.org/10.1021/acsami.3c17923
SN - 1944-8252
VL - 16
IS - 7
SP - 9517
EP - 9531
PB - American Chemical Society (ACS)
AN - OPUS4-59762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knapic, D.
A1 - Mardare, A. I.
A1 - Voss, Heike
A1 - Bonse, Jörn
A1 - Hassel, A. W.
T1 - Corrosion study of picosecond-laser structured and anodized Ti6Al4V for bone screws
N2 - A corrosion study is performed on six variations of titanium grade 5 (Ti6Al4V) samples. Samples are prepared in different conditions by variation of preanodization, postanodization, and picosecond-laser (ps-laser) surface treatment, while polished and anodized samples serve as reference. Microcones and nanosized periodic surface features are successfully produced on Ti6Al4V samples. The morphology and topography of the structures are visualized by scanning electron microscopy and white light interference microscopy. Furthermore, the relative electrochemically active surface area (ECSA) is determined for the ps-laser-treated samples. It is determined that the preanodized and laser-treated sample has 3.5 times larger ECSA than a polished sample, and that the laser-treated sample has 4.1 times larger area. Moreover, Tafel analysis is performed to determine the corrosion properties of the samples. It is shown that the corrosion resistance improves for both laser-structured samples after the anodization. To further study the surface of the samples, electrochemical impedance spectroscopy measurements are conducted. The study indicates that the ps-laser-treated and anodized Ti6Al4V is suitable to be used for the fabrication of bone screws and plates due to its improved corrosion resistance as compared to nonanodized samples.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Anodization
KW - Bone screws
KW - Implant material
KW - Titanium alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597890
DO - https://doi.org/10.1002/pssa.202300609
SN - 1862-6319
VL - 221
SP - 1
EP - 8
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-59789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nawaz, Q.
A1 - Blaeß, Carsten
A1 - Mueller, Ralf
A1 - Boccaccini, A.R.
T1 - Processing and cytocompatibility of Cu-doped and undoped fluoride-containing bioactive glasses
N2 - Sintered or additive-manufactured bioactive glass (BG) scaffolds are highly interesting for bone replacement applications. However, crystallization often limits the high-temperature processability of bioactive glasses (BGs). Thus, the BG composition must combine high bioactivity and processability. In this study, three BGs with nominal molar (%) compositions 54.6SiO2-1.7P2O3-22.1CaO-6.0Na2O-7.9K2O-7.7MgO (13–93), 44.8SiO2-2.5P2O3-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2 (F3) and 44.8SiO2-2.5P2O3-35.5CaO-6.6Na2O-6.6K2O-3.0CaF2-1.0CuO (F3–Cu) were investigated. The dissolution and ion release kinetics were investigated on milled glass powder and crystallized particles (500–600 μm). All glasses showed the precipitation of hydroxyapatite (HAp) crystals after 7 days of immersion in simulated body fluid. No significant differences in ion release from glass and crystalline samples were detected. The influence of surface roughness on cytocompatibility and growth of preosteoblast cells (MC3T3-E1) was investigated on sintered and polished BG pellets. Results showed that sintered BG pellets were cytocompatible, and cells were seen to be well attached and spread on the surface after 5 days of incubation. The results showed an inverse relation of cell viability with the surface roughness of pellets, and cells were seen to attach and spread along the direction of scratches.
KW - Bioactive glass
KW - Crystallization
KW - Solubility
KW - Cytocompatibility
KW - Surface roughness
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598257
DO - https://doi.org/10.1016/j.oceram.2024.100586
SN - 2666-5395
VL - 18
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-59825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
T1 - Semantic integration of diverse data in materials science: Assessing Orowan strengthening
N2 - AbstractThis study applies Semantic Web technologies to advance Materials Science and Engineering (MSE) through the integration of diverse datasets. Focusing on a 2000 series age-hardenable aluminum alloy, we correlate mechanical and microstructural properties derived from tensile tests and dark-field transmission electron microscopy across varied aging times. An expandable knowledge graph, constructed using the Tensile Test and Precipitate Geometry Ontologies aligned with the PMD Core Ontology, facilitates this integration. This approach adheres to FAIR principles and enables sophisticated analysis via SPARQL queries, revealing correlations consistent with the Orowan mechanism. The study highlights the potential of semantic data integration in MSE, offering a new approach for data-centric research and enhanced analytical capabilities.
KW - Semantic Interoperability
KW - Knowledge Graph
KW - Orowan Mechanism
KW - Aluminum Alloy Aging
KW - Ontology
KW - Semantic Data Integration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599780
DO - https://doi.org/10.1038/s41597-024-03169-4
VL - 11
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-59978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ratkovac, Mirjana
A1 - Gerards-Wünsche, Paul
A1 - Thiele, Marc
A1 - Brackrock, Daniel
A1 - Stamm, Michael
T1 - Detection and monitoring of the fatigue crack growth on welds – Application-oriented use of NDT methods
N2 - Early detection of fatigue cracks and accurate measurements of the crack growth play an important role in the maintenance and repair strategies of steel structures exposed to cyclic loads during their service life. Observation of welded connections is especially of high relevance due to their higher susceptibility to fatigue damage. The aim of this contribution was to monitor fatigue crack growth in thick welded specimens during fatigue tests as holistically as possible, by implementing multiple NDT methods simultaneously in order to record the crack initiation and propagation until the final fracture. In addition to well-known methods such as strain gauges, thermography, and ultrasound, the crack luminescence method developed at the Bundesanstalt für Materialforschung und -prüfung (BAM), which makes cracks on the surface particularly visible, was also used. For data acquisition, a first data fusion concept was developed and applied in order to synchronize the data of the different methods and to evaluate them to a large extent automatically. The resulting database can ultimately also be used to access, view, and analyze the experimental data for various NDT methods. During the conducted fatigue tests, the simultaneous measurements of the same cracking process enabled a comprehensive comparison of the methods, highlighting their individual strengths and limitations. More importantly, they showed how a synergetic combination of different NDT methods can be beneficial for implementation in large-scale fatigue testing but also in monitoring and inspection programs of in-service structures - such as the support structures of offshore wind turbines.
T2 - Fatigue Design 2023 (FatDes 2023)
CY - Senlis, France
DA - 29.11.2023
KW - Fatigue
KW - Welded
KW - NDT
KW - Crack growth
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600238
DO - https://doi.org/10.1016/j.prostr.2024.03.062
VL - 57
SP - 560
EP - 568
PB - Elsevier B.V.
AN - OPUS4-60023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
A1 - François, P.
T1 - ELENA Project: Creating a simplified uncertainty calculation for industrial applications
N2 - In this workpackage of the ELENA project, we develop a way to express the measurement uncertainty of nanoscale determination of electrical propserties. The method developed aims to be usable for industrial contexts and described in technical documents and standards drafts. Standards and reference samples are used to make traceable measurements available for the end user.
T2 - Congrès International de Metrologie
CY - Lyon, France
DA - 06.03.2023
KW - Nanoscale measurements
KW - Electrical properties
KW - Optical measurements
KW - Surfaces
KW - Scanning probe measurements
PY - 2023
AN - OPUS4-57155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Dynamische Lichtstreuung DLS nach ISO 22412:2017
N2 - Einführung in die Partikelgrößenbestimmung von Nano-Materialien mittels Dynamischer Lichtstreuung. Normative Grundlagen (ISO 22412 und OECD TG 125); Messprinzip, Auswertealgorithmen, Informationsgehalt der Daten, Metadaten, Reporting.
T2 - BAM Akademie: Info-Tage "NANO OR NOT NANO"
CY - Online meeting
DA - 16.02.2023
KW - DLS
KW - Particle size
KW - Nano
PY - 2023
AN - OPUS4-57128
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Exkurs Partikelgrößenverteilungen
N2 - Einführung in die Darstellung der Ergebnisse von Partikelgrößenbestimmungen:
Was ist ein Kugeläquivalenzdurchmesser; welche Bedeutung hat die gemessene Mengenart; welche Parameter werden ausgewiesen. Bezug zu Regularien hinsichtlich der Bewertung "Nano- oder nicht Nano-Material.
T2 - BAM Akademie: Info-Tage "NANO OR NOT NANO"
CY - Online meeting
DA - 16.02.2023
KW - Nano material
KW - Particle size
KW - Size distribution
PY - 2023
AN - OPUS4-57127
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Nagelschmidt, Sven
T1 - Ein Beitrag zur Zusammenführung von Zeit-Temperatur-Äquivalenz-Methoden: Entwicklung und Anwendung am Beispiel ausgewählter Materialverhalten für Zeit-Temperatur-Parameter und Zeit-Temperatur-Superpositionsprinzip
N2 - In der Wissenschaft und Technik gibt es verschiedene Gründe, um auf Basis geeigneter Modelle in die Zukunft schauen zu wollen, beispielsweise um zu bewerten, ob ein Bauteil auch noch deutlich länger verwendet werden kann als eigentlich einmal vorgesehen. Eine Methode dieses zu tun, basiert auf dem Zeit-Temperatur-Äquivalenz-Prinzip, welches besagt, dass ein Zustand oder eine Materialeigenschaft gleichwertig bei verschiedenen Zeit-Temperatur-Kombinationen auftritt oder erreicht werden kann. Höhere Temperaturen verkürzen in der Regel die Dauer und umgekehrt. In den letzten Jahrzehnten hat sich ein umfangreiches Methodenspektrum für unterschiedliche Werkstoffe und Anwendungsgebiete entwickelt, sodass die Identifikation einer geeigneten Methode für einen konkreten Anwendungsfall oder neue Materialien eine Herausforderung darstellt. These: „Fortschrittlich wäre, existierende Methoden zusammenzuführen, methodenspezifische Vorteile zu kombinieren, um mit geringerem Aufwand ein geeignetes Prognosemodell zu entwickeln.“
Für metallische Werkstoffe und Polymere verläuft die Entwicklung von Prognosemodellen mit Zeit-Temperatur-Korrelation seit ca. 1940 parallel und unabhängig voneinander. In diesem Zusammenhang bekannte Methoden sind das Zeit-Temperatur-Superpositionsprinzip und Zeit-Temperatur-Parameter, wie der LARSON-MILLER-Parameter. Die jeweiligen methodischen Ansätze sind in der Regel anwendungs- und materialspezifisch und nur einzelnen Fachartikeln zu entnehmen. Eine zusammenführende thematische Übersicht und Untersuchung existierender Methoden wurden bislang nicht publiziert. Diese Forschungsarbeit verfolgt dahingehend einen neuartigen methodischen Ansatz und zeigt untersuchte Gemeinsamkeiten und Unterschiede als auch Analogien für das Zeit-Temperatur-Superpositionsprinzip und Zeit-Temperatur-Parameter anhand bestimmter Merkmale auf. Dafür wurden verschiedene analytische und grafische Ansätze verwendet. Ferner wird eine zusammenführende Untersuchung anhand eines rheologischen Materialmodells sowie anhand eines praktischen Anwendungsbeispiels gezeigt. Hergeleitet wurde u. a., dass das Prinzip der Zeit-Temperatur-Superposition für sogenanntes thermorheologisch einfaches und komplexes Verhalten konkreten Zeit-Temperatur-Parametern zugeordnet werden können. Und dadurch Verschiebefunktionen nicht nur in Abhängigkeit der Temperatur, sondern auch abhängig vom Zustand untersucht und definiert werden können. Ferner ermöglicht eine Skalierung der Zeit-Temperatur-Parameter auf eine Referenztemperatur physikalisch anschaulichere Auswertungen analog zum Zeit-Temperatur-Superpositionsprinzip. Untersuchungen zeigen, dass sich für einen konkreten Anwendungsfall die geeignetste Zeit-Temperatur-Äquivalenz-Methode aus einer gegenseitigen Abhängigkeit bzw. Kompatibilität einzelner Elemente, wie zugrunde gelegte Daten, Koordinatenachsenskalierung, ermittelte Zeit-Temperatur-Äquivalenz, Masterfunktionsansatz und der geforderten Interpolationsgüte herleitet.
Der gewählte Forschungsansatz und die erzielten Ergebnisse bieten eine Plattform für die weitere Entwicklung von Prognosemodellen auf Basis des Zeit-Temperatur-Äquivalenz-Prinzips, insbesondere im Hinblick auf eine Zusammenführung und Kombination existierender Methoden.
KW - Zeit-Temperatur-Äquivalenz
KW - Zeit-Temperatur-Korrelation
KW - Zeit-Temperatur-Superposition
KW - Extrapolation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601530
DO - https://doi.org/10.14279/depositonce-20439
SP - 1
EP - 145
CY - TU Bibliothek online
AN - OPUS4-60153
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kuchenbecker, Petra
T1 - Zentrifugen Sedimentationsverfahren CLS nach ISO 13318 2:2007
N2 - Einführung in die Bestimmung der Partikelgröße von Nano-Materialien mittels Zentrifugen Sedimentationsverfahren CLS nach ISO 13318 2:2007.
Normative Grundlagen (einschließlich OECD TG 125), Messprinzip, Auswertung, Vor- und Nachteile der Methode, Metadaten, Reporting.
T2 - BAM Akademie: Info-Tage "NANO OR NOT NANO"
CY - Online meeting
DA - 16.02.2023
KW - CLS
KW - Particle size
KW - Nano
PY - 2023
AN - OPUS4-57129
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grundmann, Jana
A1 - Bodermann, Bernd
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - Hertwig, Andreas
A1 - Klapetek, Petr
A1 - Rafighdoost, Jila
A1 - Pereira, Silvania F.
T1 - Optical and tactile measurements on SiC sample defects
N2 - Abstract. In power electronics, compound semiconductors with large bandgaps, like silicon carbide (SiC), are increasingly being used as material instead of silicon. They have a lot of advantages over silicon but are also intolerant of nanoscale material defects, so that a defect inspection with high accuracy is needed. The different defect types on SiC samples are measured with various measurement methods, including optical and tactile methods. The defect types investigated include carrots, particles, polytype inclusions and threading dislocations, and they are analysed with imaging ellipsometry, coherent Fourier scatterometry (CFS), white light interference microscopy (WLIM) and atomic force microscopy (AFM). These different measurement methods are used to investigate which method is most sensitive for which type of defect to be able to use the measurement methods more effectively. It is important to be able to identify the defects to classify them as critical or non-critical for the functionality of the end product. Once these investigations have been completed, the measurement systems can be optimally distributed to the relevant defects in further work to realize a hybrid analysis of the defects. In addition to the identification and classification of defects, such a future hybrid analysis could also include characterizations, e.g. further evaluation of ellipsometric data by using numerical simulations.
KW - Compound semiconductors
KW - Hybrid metrology
KW - Material defects
KW - Spectroscopic ellipsometry
KW - Scanning probe microscopy
KW - White-light interference microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601220
DO - https://doi.org/10.5194/jsss-13-109-2024
SN - 2194-878X
VL - 13
IS - 1
SP - 109
EP - 121
PB - Copernicus Publ.
CY - Göttingen
AN - OPUS4-60122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hashemi, Seyedreza
A1 - Zscherpel, Uwe
T1 - Measurement of Focal Spots of X-ray Tubes Using a CT Reconstruction Approach on Edge Images of Large Holes and Comparison to Pinhole Imaging
N2 - The first Non-destructive testing (NDT) method which evolved in the industrial age was radiographic testing (RT). Among all NDT methods, RT is no exception, so there are still many issues for optimizations even today. One of them is the measurement of the focal spot of X-ray tubes. The size of the focal spot is critical for imaging, because it determines the spatial resolution in the X-ray image. The classical way to evaluate focal spots of X-ray tubes is by pinhole imaging using a camera obscura. But this method has a natural lower limit, which is defined by the diameter of the pinhole used (today min. 10 µm). Therefore, focal spot sizes lower than 50 µm diameter cannot be imaged and measured correctly. An alternative approach, which permits this, was investigated here using the edge unsharpness of holes much larger than the focal spot size. The results of both methods were compared using 3 different X-ray tubes.
KW - Reconstruction method
KW - Radiographic testing (RT) using X-rays
KW - Focal spot measurement
KW - Edge unsharpness
KW - X-ray tubes
KW - Pinhole imaging
KW - Computed Tomography (CT)
KW - Focal Spot (FS)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608646
DO - https://doi.org/10.58286/29556
SN - 2941-4989
SP - 1
EP - 9
PB - NDT.net
CY - Berlin, Germany
AN - OPUS4-60864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bulling, Jannis
T1 - Mass Lumping for Scaled Boundary Polygonal Elements
N2 - Many modern ultrasonic methods in the fields of Non-Destructive Testing (NDT) and Structural Health Monitoring (SHM) require simulations in research. Researchers either use simulation data initially during development to investigate certain aspects, or the simulation process is directly part of the research task. Examples of the second case are inverse methods for parameter estimation, model-assisted probability of detection analysis or the generation of training data for AI algorithms. All these applications require algorithms that are as efficient as possible. For methods based on explicit time-step methods, a significant increase in efficiency can be achieved if a so-called lumped mass matrix can be used, which approximates the consistent mass matrix but is easier to invert.
The finite element method has been the subject of many studies on approximations of the mass matrix. In contrast, the lumped mass matrix in the context of the Scaled Boundary Finite Element Method (SBFEM) is a current field of research [1,2]. In the time domain, the semi-analytical SBFEM is notable for its flexibility to be applied to polygonal meshes. In particular, image-based mesh generation using a quadtree algorithm is possible. In general, polygonal meshes have the same flexibility as triangular meshes, but polygonal meshes can have additional advantages such as greater tolerance to distortion.
In this contribution, the SBFEM formulation based on bubble functions [3] for the time domain is presented for two-dimensional elastic waves. The adjustments necessary for a good approximating lumped mass matrix are emphasized. Several grid generation methods for polygonal elements are shown. Figure 1 depicts the difference between the consistent mass matrix and the lumped mass matrix for a normal polygonal mesh. Finally, the accuracy of mass lumping for linear, quadratic and cubic shape functions is presented and the computational efficiency is demonstrated using exemplary waveguide geometries.
T2 - Guided Ultrasonic Waves: Emerging Methods (GUWEM)
CY - Überherrn, Germany
DA - 08.07.2024
KW - Scaled boundary finite element method
KW - Mass lumping
KW - Guided waves
PY - 2024
UR - https://doi.org/10.5281/zenodo.12517188
AN - OPUS4-60766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - da Costa, P. F. G. M.
A1 - Merízio, L. G.
A1 - Wolff, N.
A1 - Terraschke, H.
A1 - de Camargo, Andrea Simone Stucchi
T1 - Real-time monitoring of CdTe quantum dots growth in aqueous solution
N2 - Quantum dots (QDs) are remarkable semiconductor nanoparticles, whose optical properties are strongly size-dependent. Therefore, the real-time monitoring of crystal growth pathway during synthesis gives an excellent opportunity to a smart design of the QDs luminescence. In this work, we present a new approach for monitoring the formation of QDs in aqueous solution up to 90 °C, through in situ luminescence analysis, using CdTe as a model system. This technique allows a detailed examination of the evolution of their light emission. In contrast to in situ absorbance analysis, the in situ luminescence measurements in reflection geometry are particularly advantageous once they are not hindered by the concentration increase of the colloidal suspension. The synthesized particles were additionally characterized using X-ray diffraction analysis, transition electron microscopy, UV-Vis absorption and infrared spectroscopy. The infrared spectra showed that 3-mercaptopropionic acid (MPA)-based thiols are covalently bound on the surface of QDs and microscopy revealed the formation of CdS. Setting a total of 3 h of reaction time, for instance, the QDs synthesized at 70, 80 and 90 °C exhibit emission maxima centered at 550, 600 and 655 nm. The in situ monitoring approach opens doors for a more precise achievement of the desired emission wavelength of QDs.
KW - CdTe quantum dots
KW - In situ synthesis
KW - Real time growth control
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603596
DO - https://doi.org/10.1038/s41598-024-57810-8
SN - 2045-2322
VL - 14
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-60359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Fengchan
A1 - Oiticica, Pedro Ramon Almeida
A1 - Abad-Arredondo, Jaime
A1 - Arai, Marylyn Setsuko
A1 - Oliveira, Osvaldo N.
A1 - Jaque, Daniel
A1 - Fernandez Dominguez, Antonio I.
A1 - de Camargo, Andrea Simone Stucchi
A1 - Haro-González, Patricia
T1 - Brownian Motion Governs the Plasmonic Enhancement of Colloidal Upconverting Nanoparticles
N2 - Upconverting nanoparticles are essential in modern photonics due to their ability to convert infrared light to visible light. Despite their significance, they exhibit limited brightness, a key drawback that can be addressed by combining them with plasmonic nanoparticles. Plasmon-enhanced upconversion has been widely demonstrated in dry environments, where upconverting nanoparticles are immobilized, but constitutes a challenge in liquid media where Brownian motion competes against immobilization.
This study employs optical tweezers for the three-dimensional manipulation of an individual upconverting nanoparticle, enabling the exploration of plasmon-enhanced upconversion luminescence in water. Contrary to expectation, experiments reveal a long-range (micrometer scale) and moderate (20%) enhancement in upconversion luminescence due to the plasmonic resonances of gold nanostructures. Comparison between experiments and numerical simulations evidences the key role of Brownian motion. It is demonstrated how the three-dimensional Brownian fluctuations of the upconverting nanoparticle lead to an “average effect” that explains the magnitude and spatial extension of luminescence enhancement.
KW - Upconversion
KW - Plasmon enhancement
KW - Optical tweezers
KW - Brownian motion
KW - Nanoparticles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603551
DO - https://doi.org/10.1021/acs.nanolett.4c00379
VL - 24
IS - 12
SP - 3785
EP - 3792
PB - American Chemical Society (ACS)
AN - OPUS4-60355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Plasmonic Behavior in Assemblies of Disordered Gold Nanoparticles
N2 - Plasmons are collective oscillations of the free electron density in metals which can be described by an electromagnetic field. Surface plasmons are longitudinal waves propagating at the surface of the metallic material coupled to an external field. Localized surface plasmons on a nanoparticle reveal the behavior of standing waves with discrete resonance frequencies whose dominating mode is called dipole mode. Coupling of nanoparticles leads eventually to a hybridization of those dipole modes and therefore to spectral and spatial delocalization which was already investigated in ordered systems. In disordered systems, there are a lot of open questions regarding the propagation behavior which changes from delocalization to localization for instance due to the disorder. This phenomenon is then called Anderson localization. To investigate the propagation behavior of plasmonic waves in an assembly of disordered gold NPs, we combine experimental results of electron energy loss spectroscopy in a scanning transmission microscope with simulation results of the self-consistent dipole modelling. We indeed find experimentally localization of plasmon modes and with the simulation we could exclude other localization mechanism such as life-time damping or retardation. In conclusion, we could found Anderson localization of surface plasmons in assemblies of disordered gold nanoparticles which will enhance the understanding of this kind of vector waves to the Anderson localization as a general wave behavior in disordered systems.
T2 - PhD seminar Leipniz Institut for solid state and material research (IFW Dresden)
CY - Dresden, Germany
DA - 19.06.2024
KW - Plasmonic
KW - EELS in STEM
KW - Self-consistent dipole model
KW - Assemblies of gold nanoparticles
PY - 2024
AN - OPUS4-60945
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Held, Mathias
A1 - Bulling, Jannis
A1 - Lugovtsova, Yevgeniya
A1 - Prager, Jens
T1 - Determination of isotropic elastic constants from dispersion images based on ultrasonic guided waves by using neural networks
N2 - This article presents a method to use the dispersive behavior of ultrasonic guided waves and neural networks to determine the isotropic elastic constants of plate-like structures through dispersion images. Therefore, two different architectures are compared: one using convolutions and transfer learning based on the EfficientNetB7 and a Vision Transformer-like approach. To accomplish this, simulated and measured dispersion images are generated, where the first is applied to design, train, and validate and the second to test the neural networks. During the training of the neural networks, distinct data augmentation layers are employed to introduce artifacts appearing in measurement data into the simulated data. The neural networks can extrapolate from simulated to measured data using these layers. The trained neural networks are assessed using dispersion images from seven known material samples. Multiple variations of the measured dispersion images are tested to guarantee the prediction stability. The study demonstrates that neural networks can learn to predict the isotropic elastic constants from measured dispersion images using only simulated dispersion images for training and validation without needing an initial guess or manual feature extraction, independent of the measurement setup. Furthermore, the suitability of the different architectures for generating information from dispersion images in general is discussed.
KW - Ultrasonic guided waves
KW - Dispersion
KW - Elastic constants
KW - Neural networks
KW - Image processing
KW - Vision transformer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607090
DO - https://doi.org/10.1016/j.ultras.2024.107403
SN - 0041-624X
VL - 143
SP - 1
EP - 48
PB - Elsevier B.V.
AN - OPUS4-60709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Characterisation of thin layers of Polydopamine used as functional coatings in X-Ray optics
N2 - Polydopamine (PDA) is a biological / biomimetic polymer which has spiked considerable interest in recent years. Its monomer is an important neurotransmitter and it is one of the strongest glues produced by biological organisms. Polydopamine is a candidate for several applications, mainly in the field of biology and medicine, but also - recently - for layer coatings with optical, electrical, and mechanical function.
In this work, we investigate PDA layers intended as reflectivity enhancers for mirror surfaces in X-ray astronomical observatories. It has previously been shown, that such X-ray telescopes can be improved by a coating of PDA in the thickness range of several nm. Accurate thickness determination is required to monitor and optimise the coating process. We use spectroscopic ellipsometry to determine first the dielectric function of the polydopamine layers using model coatings of sufficient thickness. This data is then used to accurately determine the layer thickness of much thinner PDA layers. This study resulted in data on the thickness and dielectric function of PDA layers that could lead to a better understanding of the correlation of layer thickness and layer properties depending on the process parameters.
T2 - Deutsche Physikalische Gesellschaft - Frühjahrstagung
CY - Berlin, Germany
DA - 17.03.2024
KW - Polydopamine
KW - Thin Solid Layers
KW - X-ray optics
KW - Spectroscopic Ellipsometry
PY - 2024
AN - OPUS4-60955
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulrich, A. S.
A1 - Kasatikov, S.
A1 - König, T.
A1 - Fantin, Andrea
A1 - Margraf, J. T.
A1 - Galetz, M. C.
T1 - Decreased Metal Dusting Resistance of Ni-Cu Alloys by Fe and Mn Additions
N2 - Ni-Cu alloys are promising for application at temperatures between 400–900 °C and reducing atmospheres with high C-contents. Typically, under such conditions, metallic materials in contact with the C-rich atmosphere are degraded by a mechanism called metal dusting (MD). Ni-Cu-alloys do not form protective oxide scales, but their resistance is attributed to Cu, which catalytically inhibits the C-deposition on the surface. Adding other alloying elements, such as Mn or Fe, was found to enhance the MD attack of Ni-Cu alloys again. In this study, the effect of the Mn and Fe is divided into two affected areas: the surface and the bulk. The MD attack on binary Ni-Cu alloys, model alloys with Fe and Mn additions, and commercial Monel Alloy 400 is experimentally demonstrated. The surface electronic structure causing the adsorption and dissociation of C-containing molecules is investigated for model alloys. Analytical methods such as scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, electron probe microanalysis combined with wavelength-dispersive X-ray spectroscopy, X-ray diffraction analysis, and near-edge X-ray absorption fine structure measurements were used. The results are correlated to CALPHAD calculations and atomistic simulations combining density functional theory calculations and machine learning. It is found that the Cu content plays a significant role in the surface reaction. The effect of Mn and Fe is mainly attributed to oxide formation. A mechanism explaining the enhanced attack by adding both Fe and Mn is proposed.
KW - Metal Dusting
KW - XANES
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608226
DO - https://doi.org/10.1007/s11085-024-10263-w
SN - 2731-8397
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-60822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Keller, Christian
T1 - Beitrag zur numerischen Beanspruchungsanalyse an dünnwandigen Stahlblechcontainern im Fallversuch - Schädigungsmechanische Materialmodellierung duktiler Werkstoffe unter Berücksichtigung der Dehnratenabhängigkeit der plastischen Instabilität
N2 - Gegenstand der vorliegenden Arbeit ist die Bereitstellung expliziter numerischer Simulationen von Fallversuchen mit dünnwandigen Stahlblechcontainern, die als Endlagerbehälter für radioaktive Abfälle mit vernachlässigbarer Wärmeentwicklung, d. h. schwach- und mittelradioaktive Abfälle, für die Verbringung in das Endlager Konrad vorgesehen sind. Die Betrachtung von potentiellen Absturzszenarien ist ein grundlegender und zentraler Bestandteil der Sicherheitsnachweise zur Auslegung der verschiedenen endlagergängigen Behälter- und Containertypen gegen mechanische Störfallbelastungen. Für dünnwandige Stahlblechcontainer existierten bislang keine sicherheitstechnischen Untersuchungen, die auf numerischen Bewertungsmethoden basieren und eine Bewertung der vorhandenen Sicherheitsreserven hinsichtlich der mechanischen Integrität ermöglichen. Daraus resultierte die Motivation, ein verifiziertes Finite-Elemente-Modell eines repräsentativen Referenzcontainers zu entwickeln, das das dynamische Verformungs- sowie duktile Schädigungs- und Versagensverhalten in numerischen Simulationen von dynamischen Lastfällen physikalisch mit der erforderlichen Güte beschreibt.
Duktile Schädigungs- und Versagensvorgänge metallischer Werkstoffe gehen grundsätzlich mit großen plastischen Dehnungen einher und führen somit unweigerlich zu der Notwendigkeit der Diskussion von plastischer Instabilität und damit verknüpften Lokalisierungseffekten, die einen wesentlichen Einfluss auf die Entwicklung des lokalen Beanspruchungszustands haben. Für die schädigungsmechanische Materialmodellierung folgt hieraus das grundsätzliche Erfordernis der korrekten Berücksichtigung des Instabilitätsbeginns, der in der Regel dehnratenunabhängig angenommen wird. Für dynamische Randbedingungen ist der werkstoffspezifische Einfluss der Dehnrate auf das Einsetzen der Lokalisierung jedoch nicht uneingeschränkt vernachlässigbar, so dass im Rahmen dieser Arbeit ein theoretischer Ansatz ausgearbeitet wird, der die plastische Instabilität dehnratenabhängiger Werkstoffe anhand des zeit- und ortsabhängigen Dehnungsgradienten im einachsigen Zugversuch diskutiert. Darüber hinaus ist für eine hinreichend genaue Materialmodellierung neben der korrekten Prognose des Instabilitätsbeginns auch die korrekte Beschreibung des Verformungsverhaltens jenseits der Gleichmaßdehnung notwendig. Zu diesem Zweck wird in dieser Arbeit eine konstitutive Beziehung entwickelt, die sowohl unter Berücksichtigung der plastischen Instabilität als auch unter der Beachtung von ver- sowie entfestigenden Einflussfaktoren der dynamischen Plastizität formuliert werden kann.
Insgesamt wird eine praxistaugliche Bewertungsmethode der mechanischen Integrität dünnwandiger Stahlblechcontainer unter Störfallbedingungen auf Basis expliziter dynamischer Simulationen erarbeitet, die die komplexen duktilen Schädigungs- und Versagensmechanismen dehnratenabhängiger Werkstoffe berücksichtigt. Mit der zur Simulation von Fallversuchen entwickelten numerischen Modellbildung und den zur Verifizierung entsprechend mit Testcontainern im Originalmaßstab durchgeführten Fallversuchen wird nachgewiesen, dass anhand des Finite-Elemente-Modells eines repräsentativen Referenzcontainers zum einen eine quantitativ belegte Bestimmung ungünstiger Fallorientierungen hinsichtlich maximaler Verformungen und zum anderen eine realistische Abbildung des duktilen Versagensverhaltens ermöglicht wird. Damit können tatsächlich vorhandene Sicherheitsreserven bei potentiell zu unterstellenden Behälterabstürzen quantitativ aufgezeigt und zukünftig eine verbesserte sicherheitstechnische Beurteilung von Stahlblechcontainern im Fallversuch bereitgestellt werden. Damit leistet die vorliegende Arbeit einen wichtigen Beitrag für die Bewertung von Sicherheitsnachweisen von Endlagerbehältern für radioaktive Abfälle und trägt dazu bei, den langfristigen Schutz von Mensch und Umwelt vor Schäden durch radioaktive Stoffe zu gewährleisten.
N2 - The subject of the present work is the provision of explicit numerical simulations of drop tests with thin-walled sheet steel containers, which are intended as repository containers for radioactive waste with negligible heat generation, i.e. low and intermediate level waste, for shipment to the Konrad repository. The consideration of potential crash scenarios is a fundamental and central component of the safety analyses for the design of the various types of casks and containers suitable for final disposal against mechanical accident loads. For thin-walled sheet steel containers, no safety investigations based on numerical assessment methods existed so far that would allow an evaluation of the existing safety reserves with regard to mechanical integrity. This resulted in the motivation to develop a verified finite element model of a representative reference container that physically describes the dynamic deformation and ductile damage and failure behaviour in numerical simulations of dynamic load cases with the required quality.
Ductile damage and failure processes of metallic materials are fundamentally accompanied by large plastic strains and thus inevitably lead to the need to discuss plastic instability and associated localisation effects, which have a significant influence on the development of the local stress state. For damage-mechanical material modelling this results in the fundamental requirement of correctly considering the onset of instability, which is usually assumed to be strain-rate independent. For dynamic boundary conditions, however, the material-specific influence of the strain rate on the onset of localisation cannot be neglected without restriction, so that a theoretical approach is elaborated within the scope of this work that discusses the plastic instability of strain-rate-dependent materials on the basis of the time- and location-dependent strain gradient in the uniaxial tensile test. Furthermore, for a sufficiently accurate material modelling, besides the correct prediction of the onset of instability, the correct description of the deformation behaviour in the postcritical region, i.e., beyond the uniform strain, is necessary. For this purpose, a constitutive relationship is developed in this work, which can be formulated both under consideration of the plastic instability as well as under consideration of hardening as well as softening influencing factors of the dynamic plasticity.
Overall, a practical assessment method of the mechanical integrity of thin-walled sheet steel containers under accident conditions is developed based on explicit dynamic simulations, which takes into account the complex ductile damage and failure mechanisms of strain rate-dependent materials. With the numerical modelling developed for the simulation of drop tests and the drop tests carried out accordingly with full-scale test containers for verification, it is demonstrated that, on the basis of the finite element model of a representative reference container, on the one hand a quantitatively proven determination of unfavourable drop orientations with regard to maximum deformations and, on the other hand, a realistic representation of the ductile failure behaviour is made possible. This allows it to quantitatively demonstrate actually existing safety reserves in case of potential container crashes and to provide an improved safety assessment of sheet steel containers in drop tests in the future. This work thus makes an important contribution to the evaluation of safety verifications of final storage containers for radioactive waste and helps to ensure the long-term protection of humans and the environment from damage caused by radioactive substances.
KW - FEM
KW - Dynamische Plastizität
KW - Plastische Instabilität
KW - Duktile Schädigung
KW - Endlager Konrad
PY - 2024
DO - https://doi.org/10.14279/depositonce-21874
SP - 1
EP - 188
PB - DepositOnce
CY - Berlin
AN - OPUS4-61581
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elahi, Seyed Ahmad
A1 - Mehri Sofiani, F.
A1 - Chaudhuri, Somsubhro
A1 - Balbin, J.A.
A1 - Larossa, N.O.
A1 - De Waele, Wim
T1 - A numerical study on fatigue strength degradation due to pitting corrosion of S355 structural steel in a marine environment
N2 - This study investigates the influence of pitting corrosion on the fatigue strength of S355 steel, commonly used in offshore wind support structures. A short crack microstructural model is employed to estimate the degraded fatigue strength, effectively capturing the physics of the problem with minimal input parameters. Material characterization tests provide the key mechanical properties of S355 steel.
A parametric analysis is used to examine the effects of pit shape, size, and aspect ratio. A generic relationship is identified between degraded fatigue strength and pit size for various pit aspect ratios. A sensitivity analysis reveals that the pit aspect ratio significantly influences fatigue strength, with sharper pits leading to greater reductions. The threshold stress intensity factor has a moderate effect, while in-air fatigue strength and grain size have minimal impacts.
A case study is performed to evaluate the fatigue strength degradation of S355 steel exposed to the North Sea environment. Findings indicate that the most severe degradation occurs in the initial years of exposure, with the degradation rate declining over time. The results align well with experimental data, offering a robust framework for assessing structural integrity in a marine environment.
KW - Fatigue strength
KW - Corrosion fatigue
KW - Pitting corrosion
KW - Short crack
KW - Micromechanical model
KW - S355 structural steel
PY - 2025
DO - https://doi.org/10.1016/j.engfailanal.2025.109669
SN - 1873-1961
VL - 177
SP - 1
EP - 21
PB - Elsevier Ltd.
AN - OPUS4-63062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lüders, C.
A1 - Kalinka, Gerhard
A1 - Li, Wei
A1 - Sinapius, M.
A1 - Wille, T.
T1 - Experimental and numerical multiscale approach to thermally cycled FRP
N2 - Due to the different thermal expansion of the constituent materials, cyclic thermal loading of FRP induces alternating stresses in the material at two scales: at the micro scale (level of fibre–matrix-interaction) and at the macro scale (level of the multidirectional laminate). Especially the micro scale effect is not comprehensively investigated yet. Additionally, computational investigations mostly neglect this effect due to the homogenous modelling of the composite material. As this effect is assumed to significantly contribute to the fatigue of FRP at thermal loads, the present paper suggests an experimental and numerical multiscale approach including Experiments at the different involved material scales to separately observe the effects acting at these scales. The approach also includes numerical modelling for each scale to complement the knowledge gained from the Experiments and to create a basis for the consideration of the micro effect even in macroscopic fatigue models treating homogeneous modelled composites. The main focus of the contribution is to bring the overall Approach up for discussion, rather than to present the multiscale modelling details.
KW - Fatigue
KW - Thermal cycling
KW - Fibre reinforced plastic
KW - Cryogenic
KW - Carbon Fibre
KW - Epoxy Resin
PY - 2020
DO - https://doi.org/10.1016/j.compstruct.2020.112303
SN - 0263-8223
VL - 244
SP - 112303
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-50844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wu, Cheng-Chieh
A1 - Weisbrich, S.
A1 - Burger, M.
A1 - Neitzel, F.
ED - Zemčík, R.
T1 - A four-point bending test apparatus for measurement- and model-based structural analysis
N2 - By means of a small-scale truss bridge, the ability of the Measurement- and Model-based Structural Analysis to detect and localise damage was examined in. Although there was no noteworthy difficulty in detecting damage, it turned out that damage localisation responds sensitively to systematic influences, i.e. non-modelled properties of the mechanical model. Therefore, another experiment is being conducted to re-examine the Measurement- and Model-based Structural Analysis. For this purpose, the bending test is carried out as it has been already theoretically respectively numerically discussed in. In this attempt, the systematic influences such as residual stress are kept as low as possible.
T2 - 36th Danubia Adria Symposium on Advances in Experimental Mechanics
CY - Pilsen, Czech Republic
DA - 24.09.2019
KW - Damage detection
KW - Adjustment calculation
KW - Finite element method
KW - Integrated analysis
PY - 2020
UR - http://www.sciencedirect.com/science/article/pii/S2214785320326432
DO - https://doi.org/10.1016/j.matpr.2020.04.028
SN - 2214-7853
VL - 32
IS - 2
SP - 156
EP - 161
PB - Elsevier Ltd.
AN - OPUS4-51551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Acosta-Zepeda, C.
A1 - Saavedra, S.
A1 - Bonse, Jörn
A1 - Haro-Poniatowski, E.
T1 - Modelling of single UV nanosecond pulsed laser surface modifications of silicon
N2 - Irradiation with a single spatially Gaussian-shaped nanosecond laser pulse in the melting regime can result in a characteristic annular change in the surface morphology of crystalline silicon. This has been verified experimentally in a variety of situations, where dimple-shaped surface topographies are produced. In a recent work we have investigated the induced changes in the surface topography upon exposure to wavelengths in the visible and near infrared spectral region. Irradiation in the UV requires a more detailed analysis due to the enhanced absorption of the material. In the present analysis, we determine under which conditions our previous model can be used and the corresponding results are presented.
KW - Laser
KW - Silicon
KW - Surface modification
PY - 2020
DO - https://doi.org/10.1088/1555-6611/ab9b2c
SN - 1555-6611
SN - 1054-660X
VL - 30
IS - 8
SP - 086003-1
EP - 086003-4
PB - IOP Publishing / Astro Ltd
CY - Bristol, United Kingdom
AN - OPUS4-51022
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Pfeffer, M.
ED - Bonse, Jörn
ED - Lasagni, A. F.
T1 - Topical issue: Laser micro- and nano-material processing - Part 1
N2 - This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods.
KW - Laser processing
KW - Microstructures
KW - Nanostructures
KW - Applications
PY - 2020
UR - https://www.degruyter.com/view/journals/aot/9/1-2/aot.9.issue-1-2.xml
SN - 2193-8576
SN - 2193-8584
VL - 9
IS - 1-2
SP - 7
EP - 110
PB - De Gruyter
CY - Berlin
AN - OPUS4-50798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezera, Marek
T1 - Bacterial adhesion on femtosecond laser-induced periodic surface structures
N2 - Biofilm formation in industrial or medical settings is usually unwanted and leads to serious health problems and high costs. Inhibition of initial bacterial adhesion prevents biofilm formation and is, therefore, a major mechanism of antimicrobial action of surfaces. Surface topography largely influences the interaction between bacteria and surfaces which makes topography an ideal base for antifouling strategies and eco-friendly alternatives to chemical surface modifications. Femtosecond laser-processing was used to fabricate sub-micrometric surface structures on silicon and stainless steel for the development of antifouling topographies on technical materials.
T2 - Future Tech Week 2020
CY - Online meeting
DA - 21.09.2020
KW - Laser-induced periodic surface structures (LIPSS)
KW - Bacterial adhesion
KW - Biofilm growth
KW - Structural color
KW - Femtosecond laser processing
PY - 2020
UR - http://futuretechweek.fetfx.eu/wp-content/uploads/gravity_forms/2-5432af7ecff9e0243d7383ab3f931ed3/2020/09/BioCombs4Nanofibers_Poster-for-Future_Tech_Week_2020_08-09-2020_with_Reprint-permission_for_upload.pdf
AN - OPUS4-51233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shahsanaei, Majid
A1 - Farahbakhsh, Nastaran
A1 - Pour-Ali, Sadegh
A1 - Schardt, Annika
A1 - Orangpour, Setareh
A1 - Engelhard, Carsten
A1 - Mohajernia, Shiva
A1 - Killian, Manuela S.
A1 - Hejazi, Sina
T1 - Synergistic enhancement of photocatalytic hydrogen production in TiO2 nanosheets through light-induced defect formation and Pt single atoms
N2 - In this investigation, we present a direct method employing UV-light radiation to induce point defects, specifically Ti3+ and VO, onto the surface of TiO2 nanosheets (TiO2-NSs) and efficiently decorate them with Pt particles. The addition of the Pt precursor is carried out during rest periods following UV-light cessation (light-induced samples, LI) and during UV-light exposure (photo-deposited samples, PD). The size and distribution of Pt particles on both LI and PD TiO2-NSs are systematically correlated with varying resting times, enabling precise control over Pt loading. The characterization of various TiO2-NSs is extensively conducted using microscopy techniques (FESEM, TEM, and HAADF-STEM) and spectroscopy (XPS). Gas chromatography is also employed for the evaluation of the H2 photocatalytic performance of various samples. Our findings reveal that Pt particles deposit on the TiO2-NSs surfaces as nanoparticles under illumination. After a 5 minutes resting time, a combination of Pt single atoms (SAs) and clusters, with a maximum loading of 0.37 at%, is formed. Extending the resting time to 60 minutes results in a gradual reduction in Pt SAs and clusters, leading to the deposition of Pt nanoparticles with lower loadings. Notably, Pt SAs and clusters exhibit superior performance in hydrogen evolution, showcasing a remarkable 4000-fold increase over pristine TiO2-NSs. Additionally, sustained UV radiation during Pt addition in the photo-deposited samples results in the formation of Pt nanoparticles with lower loading compared to LI samples, consequently diminishing photocatalytic hydrogen production. This study not only provides insights into the controlled manipulation of Pt SAs on TiO2-NSs but also highlights their exceptional efficacy in hydrogen evolution, offering valuable contributions to the design of efficient photocatalytic systems for sustainable hydrogen generation.
KW - Chemistry
KW - Nanosheets
KW - Hydrogen
PY - 2024
DO - https://doi.org/10.1039/D4TA01809E
VL - 12
IS - 29
SP - 18554
EP - 18562
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61271
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wojciak, K.
A1 - Tokarski, T.
A1 - Cios, G.
A1 - Nolze, Gert
T1 - Precision and accuracy during standard-less mapping of local lattice distortions using ebsd and calm technique
N2 - Electron Back Scatter Diffraction (EBSD) is a very versatile analytical technique allowing for the characterization of material structure. Historically, diffraction images (Kikuchi patterns) registered during EBSD analysis were solved using Hough/Radon transformation. The last decade brought several novel techniques of experimental pattern analysis, focusing entirely on image analysis routines such as pattern matching, or various variants of High-Resolution EBSD. However, all the above-mentioned techniques require prior knowledge of the material structure to perform orientation analysis. The recently presented algorithm employed in Crystallographic Analysis of Lattice Metric (CALM) software, effectively removes this limitation enabling a standard-less analytical approach in EBSD systems. At its core, the CALM technique couples accurate detection of the Kikuchi bands position, with a rigid construction of reciprocal lattice resulting from translational crystal symmetry. A unique characteristic of the methodology also gives an opportunity for application in the analysis of continuous lattice changes, for example tetragonality mapping. During mapping, however, the geometry of the gnomonic projection (represented by the projection center) is continuously altered decreasing overall algorithm efficiency. The work presents an analysis of the projection center in terms of precision and accuracy.
T2 - Oxford User Meeting 2024
CY - Krakow, Poland
DA - 14.05.2024
KW - EBSD
KW - Kikuchi
KW - Lattice parameters
KW - Ratio refinement
PY - 2024
AN - OPUS4-60087
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tokarski, T.
A1 - Nolze, Gert
T1 - Exploring Unconventional Uses of Kikuchi Pattern Analysis
N2 - The characterization of really unknown phases typically uses 70 to 150 reflectors for lattice metric calculation. The determination of the lattice parameters follows with 4% accuracy. Including a Z correction up to 1% can be reached. The precision of the lattice parameters ratios (a:b:c) is, however, better than 0.1%.
T2 - Oxford Users Meeting 2024
CY - Krakow, Poland
DA - 14.05.2024
KW - EBSD
KW - Kikuchi
KW - Lattice parameters
KW - Ratio refinement
PY - 2024
AN - OPUS4-60086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gebhardt, M.
A1 - Manolakis, I.
A1 - Chatterjee, A.
A1 - Kalinka, Gerhard
A1 - Deubener, J.
A1 - Pfnür, H.
A1 - Chakraborty, S.
A1 - Meiners, D.
T1 - Reducing the raw material usage for room temperature infusible and polymerisable thermoplastic CFRPs through reuse of recycled waste matrix material
N2 - In this work, a closed loop recycling process is investigated, which allows polymerised bulk thermoplastic matrix (Elium 150) from production waste (also referred to as recyclate) to be reused as additive in composite manufacturing by vacuum assisted resin infusion (VARI) of virgin Elium 150 monomer. It is shown that this process can save up to 7.5 wt% of virgin material usage in each processing cycle. At the same time, the thermal stability and stiffness of the composite increases with the proportion of recyclate introduced. Contemporarily, the shear and bending properties have also been observed to improve. Gel permeation chromatography (GPC) showed that the changes observed are due to an increase in molecular weight with the recyclate content. In particular, a correlation between the molecular weight and the shear properties of the composite was discovered using single fibre push-out tests.
KW - Mechanical properties
KW - Recycling
KW - Carbon fibres
KW - Fibre/matrix bond
PY - 2021
DO - https://doi.org/10.1016/j.compositesb.2021.108877
SN - 1359-8368
VL - 216
SP - 108877
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-52711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindrachuk, Vitaliy
A1 - Klunker, Andre
T1 - Phase field modeling of Hertzian cone cracks under spherica indentation
N2 - A phase field model of brittle fracture has been developed to simulate the Hertzian crack induced by penetration of a rigid sphere to an isotropic linear-elastic half-space. The fracture formation is regarded as a diffusive field variable, which is zero for the intact material and unity if there is a crack. Crack growth is assumed to be driven by a strain invariant. The numerical implementation is performed with the finite element method and an implicit time integration scheme. The mechanical equilibrium and the phase field equations are solved in a staggered manner, sequentially updating the displacement field and the phase field variable. Numerical examples demonstrate the capability of the model to reproduce the nucleation and growth of the Hertzian cone crack.
KW - Hertzian cracks
KW - Phase field model
KW - Contact mechanics
PY - 2021
DO - https://doi.org/10.1007/s11223-021-00251-9
VL - 52
IS - 6
SP - 967
EP - 974
AN - OPUS4-52276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Anja
T1 - Bacterial adhesion on ultrashort laser processed surfaces
N2 - Bacterial biofilms are multicellular communities adhering to surfaces and embedded in a self-produced extracellular matrix. Due to physiological adaptations and the protective biofilm matrix itself, biofilm cells show enhanced resistance towards antimicrobial treatment. In medical and industrial settings, biofilms on e.g. for implants or for surfaces in food-processing industry can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. As extensive usage of antibiotics and biocides can lead to the emergence of resistances, various strategies are currently developed, tested and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics. In this study, contact-less and aseptic large-area ultrashort laser scan processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials, i.e. titanium-alloy, steel, and polymer. The processed surfaces were characterized by optical and scanning electron microscopy and subjected to bacterial colonization studies with Escherichia coli test strains. For each material, biofilm results of the fs-laser treated surfaces are compared to that obtained on polished (non-irradiated) surfaces as a reference. Depending on the investigated surfaces, different bacterial adhesion patterns were found, suggesting an influence of geometrical size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself.
T2 - European Materials Research Society Spring Meeting 2021
CY - Online Meeting
DA - 31.05.2021
KW - Bacterial adhesion
KW - Biofilm formation
KW - Ultrashort laser processing
KW - Laser-induced periodic surface structures (LIPSS)
PY - 2021
UR - https://www.european-mrs.com/laser-material-processing-fundamental-interactions-innovative-applications-emrs
AN - OPUS4-52765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Bonse, Jörn
A1 - Kirner, Sabrina V.
A1 - Krüger, Jörg
ED - Sugioka, K.
T1 - Laser-Induced Periodic Surface Structures (LIPSS)
N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon and can be generated on almost any material by irradiation with linearly polarized radiation. This chapter reviews the current state in the field of LIPSS, which are formed in a “self-ordered” way and are often accompanying materials processing applications. LIPSS can be produced in a single-stage process and enable surface nanostructuring and, in turn, adaption of optical, mechanical, and chemical surface properties. Typically, they feature a structural size ranging from several micrometers down to less than 100 nm and show a clear correlation with the polarization direction of the light used for their generation. Various types of LIPSS are classified, relevant control parameters are identified, and their material-specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser
KW - Laser ablation
KW - Microstructures
KW - Nanostrcutures
PY - 2021
SN - 978-3-030-63646-3 (Print)
SN - 978-3-030-63647-0 (Online)
DO - https://doi.org/10.1007/978-3-030-63647-0_17
SP - 879
EP - 936
PB - Springer-Nature Switzerland AG
CY - Cham
ET - 1
AN - OPUS4-53728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Bonse, Jörn
A1 - Kirner, Sabrina V.
A1 - Krüger, Jörg
ED - Sugioka, K.
T1 - Laser-induced periodic surface structures (LIPSS)
N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon and can be generated on almost any material by irradiation with linearly polarized radiation. This chapter reviews the current state in the field of LIPSS, which are formed in a “self-ordered” way and are often accompanying materials processing applications. LIPSS can be produced in a single-stage process and enable surface nanostructuring and, in turn, adaption of optical, mechanical, and chemical surface properties. Typically, they feature a structural size ranging from several micrometers down to less than 100 nm and show a clear correlation with the polarization direction of the light used for their generation. Various types of LIPSS are classified, relevant control parameters are identified, and their material-specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser ablation
KW - Femtosecond laser
KW - Nanostructures
KW - Microstructures
PY - 2020
SN - 978-3-319-69537-2
DO - https://doi.org/10.1007/978-3-319-69537-2_17-1
SP - 1
EP - 59
PB - Springer Nature
CY - Cham, Switzerland
ET - 1
AN - OPUS4-51332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Lasagni, A. F.
T1 - Editorial: Laser micro- and nano-material processing – Part 1
N2 - This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods.
KW - Laser processing
KW - Microstructures
KW - Nanostructures
KW - Applications
PY - 2020
DO - https://doi.org/10.1515/aot-2020-0009
SN - 2193-8576
SN - 2193-8584
VL - 9
IS - 1-2
SP - 7
EP - 9
PB - De Gruyter
CY - Berlin
AN - OPUS4-50797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lasagni, A. F.
A1 - Bonse, Jörn
T1 - Editorial: Laser micro- and nano-material processing – Part 2
N2 - This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods.
KW - Applications
KW - Laser processing
KW - Microstructures
KW - Nanostructures
PY - 2020
DO - https://doi.org/10.1515/aot-2020-0025
SN - 2193-8576
SN - 2193-8584
VL - 9
IS - 3
SP - 111
EP - 112
PB - De Gruyter
CY - Berlin
AN - OPUS4-50995
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Pfeffer, M.
ED - Bonse, Jörn
ED - Lasagni, A. F.
T1 - Topical issue: Laser micro- and nano-material processing - Part 2
N2 - This special issue of Advanced Optical Technologies (AOT) is dedicated to the field of laser-based micro- and nanostructuring methods.
KW - Applications
KW - Laser processing
KW - Microstructures
KW - Nanostructures
PY - 2020
UR - https://www.degruyter.com/view/journals/aot/9/3/aot.9.issue-3.xml
SN - 2193-8576
SN - 2193-8584
VL - 9
IS - 3
SP - 111
EP - 153
PB - De Gruyter
CY - Berlin
AN - OPUS4-50997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Critical needs and stakeholder networks for engineered particles in air
N2 - In the frame of CCQM a new Task Group for particle characterization is being formed. This presentation is a gap analysis and stakeholder mapping for particles in air, from engineered to natural materials. The analysis was requested for the following points:
(1) critical literature on stakeholder needs and relevant metrology
(2) existing reference materials and relevant interlaboratory comparisons
(3) relevant metrology projects
(4) critical stakeholders and stakeholder networks and stakeholder surveys
T2 - CCQM IAWG/SAWG TG Particle Metrology
CY - Online meeting
DA - 09.07.2024
KW - CCQM
KW - Particle
KW - Nano
KW - Characterization
KW - Aerosol
PY - 2024
AN - OPUS4-62067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunz, C.
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
A1 - Neumann, C.
A1 - Turchanin, A.
A1 - Bartolomé, J. F.
A1 - Müller, F. A.
A1 - Gräf, S.
T1 - Tribological performance of metal-reinforced ceramic composites selectively structured with femtosecond laser-induced periodic surface structures
N2 - The impact of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on tribological properties was investigated for metal-reinforced ceramic composites (Al2O3-ZrO2-Nb). For this purpose, the metallic niobium (Nb) phase was selectively structured with LIPSS in an air environment with different values of the fs-laser peak fluence by near-infrared fs-laser radiation (λ = 1025 nm, τ = 300 fs, frep = 1 kHz), taking advantage of the different light absorption behavior of ceramic and metal. The tribological performance was evaluated by reciprocating sliding tests in a ball-on-disc configuration using Ringer's solution as lubricant. The surfaces were characterized before and after laser irradiation by optical microscopy, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy and by measuring the contact angle with Ringer's solution. The LIPSS formation resulted in an increased wetting of the surface with the lubricant. Moreover, the selectively structured composite surfaces revealed a coefficient of friction significantly reduced by a factor of ~3 when compared to the non-irradiated surface. Furthermore, the formation of a laser-induced oxidation layer was detected with NbO as the most prominent oxidation state. Selectively structured composites with outstanding mechanical properties and enhanced tribological performance are of particular interest for biomedical applications.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser ablation
KW - Ceramic matrix composites
KW - Tribology
PY - 2020
DO - https://doi.org/10.1016/j.apsusc.2019.143917
SN - 0169-4332
SN - 1873-5584
VL - 499
IS - 1
SP - 143917
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-49255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Simon, P.
ED - Ihlemann, J.
ED - Bonse, Jörn
T1 - Special issue "Laser-generated periodic nanostructures"
N2 - The study of laser-fabricated periodic nanostructures is one of the leading topics of today’s photonics research. Such structures on the surface of metals, semiconductors, dielectrics, or polymers can generate new material properties with special functionalities. Depending on the specific material parameters and the morphology of the structures, new devices such as microlasers, optical nanoswitches, optical storage devices, sensors or antifraud features can be realized. Furthermore, laser-generated surface textures can be used to improve the tribological properties of surfaces in contact and in relative motion—to reduce friction losses or wear, to modify the wettability or the cell and biofilm growth properties of surfaces through bioinspired laser engineering, for emerging medical applications, or as decoration elements for the refinement of precious goods.
This Special Issue “Laser-Generated Periodic Nanostructures” focuses on the latest experimental and theoretical developments and practical applications of laser-generated periodic structures that can be generated in a “self-organized” way (laser-induced periodic surface structures, LIPSS, ripples) or via laser interference-based direct ablation (often referred to as direct laser interference patterning, DLIP). We aimed to attract both academic and industrial researchers in order to collate the current knowledge of nanomaterials and to present new ideas for future applications and new technologies. By 8 August 2021, 22 scientific articles have been published in the Special Issue.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Direct laser-interference patterning (DLIP)
KW - Surface functionalization
KW - Laser processing
KW - Applications
PY - 2021
UR - https://www.mdpi.com/journal/nanomaterials/special_issues/laser-generated_periodic
SN - 2079-4991
VL - 10(1)-11(8)
SP - 147-1
EP - 2054-7
PB - MDPI
CY - Basel
AN - OPUS4-53099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thuy, Maximilian
T1 - Influence of molecular orientation on the environmental stress cracking resistance
N2 - Molecular orientation has a significant effect on the material properties of polymers. Preferential orientation of the microstructure (polymer chains or crystallites) in a specific direction or plane often enhances the material properties, especially if the high-strength covalent bonds are primarily exposed to loads instead of the weaker van der Waals bonds. However, the orientation-dependent microstructure and its mechanical behavior is in general already well understood by many scientific studies [1-3]. Isotropic materials are frequently required for an intrinsic material characterization without prevailing processing-induced properties, as is the case for Full Notch Creep Test (FNCT) [4] addressing environmental stress cracking (ESC) in high-density polyethylene (PE-HD) [5, 6]. Since ESC is one of the major limiting issues for long-term performance of PE-HD pipes and containers [7], which in contrast have a production-related preferential orientated microstructure due to extrusion or extrusion blow molding, it is important to additionally investigate the ESC resistance of such anisotropic microstructure.
Investigations of the slow crack growth (SCG) with respect to the molecular orientation generally obtain a factor of 1.2 up to 4.7 between crack growth perpendicular to the extrusion direction and crack growth parallel to the extrusion direction 8. Based on FNCT investigations with an aqueous detergent solution as environmental medium, hot pressed sheets with isotropic morphology are compared with extruded sheets from which specimens with different orientation angles are taken. However, the time to failure obtained by FNCT is also significantly influenced by the different cooling conditions under which the final morphology is formed. The tendency of the specimen to fail due to ESC is investigated as a function of environmental medium temperature. For a more detailed analysis of the affecting parameters in the manufacturing process, the ESC resistance is discussed considering the differences in crystallinity as revealed by thermal analysis.
T2 - 36th International Conference of the Polymer Processing Society
CY - Montreal, Canada
DA - 26.09.2021
KW - Environmental stress cracking
KW - Orientation-dependent microstructure
KW - High-density polyethylene
KW - Full Notch Creep Test
PY - 2021
AN - OPUS4-53399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Busch, R.
A1 - Tielemann, Christopher
A1 - Reinsch, Stefan
A1 - Müller, Ralf
A1 - Patzig, C.
A1 - Krause, M.
A1 - Höche, T.
T1 - Sample preparation for analytical scanning electron microscopy using initial notch sectioning
N2 - A novel method for broad ion beam based sample sectioning using the concept of initial notches is presented. An adapted sample geometry is utilized in order to create terraces with a well-define d step in erosion depth from the surface. The method consists of milling a notch into the surface, followed by glancing-angle ion beam erosion, which leads to preferential erosion at the notch due to increased local surface elevation. The process of terrace formation can be utilized in sample preparation for analytical scanning electron microscopy in order to get efficient access to the depth-dependent microstructure of a material. It is demonstrated that the method can be applied to both conducting and non-conducting specimens. Furthermore, experimental parameters influencing the preparation success are determined. Finally, as a proof-of-concept, an electron backscatter diffraction study on a surface crystallized diopside glass ceramic is performed, where the method is used to analyze orientation dependent crystal growth phenomena occurring during growth of surface crystals into the bulk.
KW - 3D etching
KW - Ion beam erosion Sectioning
KW - EBSD
KW - Sample preparation
KW - Analytical scanning electron microscopy
KW - SEM
KW - Glass Ceramic
KW - Glass
KW - Diopsid
PY - 2021
DO - https://doi.org/10.1016/j.micron.2021.103090
SN - 0968-4328
VL - 150
PB - Elsevier B.V.
AN - OPUS4-53075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulz, Wencke
T1 - Effect of corrosive atmosphere on the oxidation behavior of CrMnFeCoNi and CrCoNi alloys
N2 - High- and medium-entropy alloys (HEAs and MEAs) constitute a new class of materials. Those with a face-centered cubic (fcc) structure from the Cr-Mn-Fe-Co-Ni system have excellent mechanical properties and are considered for high-temperature applications since diffusion in these alloys was reported to be sluggish. However, their corrosion resistance at high temperatures must still be evaluated to further qualify them for such kinds of applications. Various groups studied the oxidation behavior of HEAs and MEAs under (dry) laboratory and artificial air as well as CO2/CO mixtures in different temperature ranges. Adomako et al. carried out oxidation tests in dry air between 800 °C and 1000 °C for 24 h in equiatomic CrCoNi, CrMnCoNi, and CrMnFeCoNi alloys. The authors showed that CrCoNi exhibits the best corrosion resistance at 800 °C due to the formation of a protective Cr2O3 layer. The matrix below the oxide scale was reported to be correspondingly depleted in Cr. It was further shown that the addition of Mn and Fe to CrCoNi changes the phase composition of the oxide scale at 800 °C. A Mn2O3 layer was grown during oxidation on CrMnCoNi and CrMnFeCoNi and a Cr2O3 scale was formed at the matrix/oxide scale interface. Beneath these oxide layers, Mn- and Cr-depleted zones were detected. These phase morphologies demonstrate the inward diffusion of oxygen and outward diffusion of Cr and Mn resulting in the formation of Cr2O3 and Mn2O3. In the present study, the corrosion resistance of CrMnFeCoNi and CrCoNi were confirmed and additionally characterized under further oxidizing atmospheres at 800 °C including Ar-2 Vol.% O2, Ar-2 Vol.% H20, and Ar-2 Vol.% SO2 mixtures.
T2 - 10th International Symposium on High-Temperature Corrosion and Protection of Materials
CY - Online meeting
DA - 28.03.2021
KW - High-entropy alloys
KW - High-temperature corrosion
KW - Chromium oxide
KW - Manganese oxide
PY - 2021
AN - OPUS4-53143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, C.
A1 - Battig, Alexander
A1 - Schartel, Bernhard
A1 - Siegel, R.
A1 - Senker, J.
A1 - von der Forst, I.
A1 - Unverzagt, C.
A1 - Agarwal, S.
A1 - Möglich, A.
A1 - Greiner, A.
T1 - Investigation of the Thermal Stability of Proteinase K for the Melt Processing of Poly(L‑lactide)
N2 - The enzymatic degradation of aliphatic polyesters offers unique opportunities for various use cases in materials science. Although evidently desirable, the implementation of enzymes in technical applications of polyesters is generally challenging due to the thermal lability of enzymes. To prospectively overcome this intrinsic limitation, we here explored the thermal stability of proteinase K at conditions applicable for polymer melt processing, given that this hydrolytic enzyme is well established for its ability to degrade poly(L-lactide) (PLLA). Using assorted spectroscopic methods and enzymatic assays, we investigated the effects of high temperatures on the structure and specific activity of proteinase K. Whereas in solution, irreversible unfolding occurred at temperatures above 75−80 °C, in the dry, bulk state, proteinase K withstood prolonged incubation at elevated temperatures. Unexpectedly little activity loss occurred during incubation at up to 130 °C, and intermediate levels of catalytic activity were preserved at up to 150 °C. The resistance of bulk proteinase K to thermal treatment was slightly enhanced by absorption into polyacrylamide (PAM) particles. Under these conditions, after 5 min at a temperature of 200 °C, which is required for the melt processing of PLLA, proteinase K was not completely denatured but retained around 2% enzymatic activity. Our findings reveal that the thermal processing of proteinase K in the dry state is principally feasible, but equally, they also identify needs and prospects for improvement. The experimental pipeline we establish for proteinase K analysis stands to benefit efforts directed to this end. More broadly, our work sheds light on enzymatically degradable polymers and the thermal processing of enzymes, which are of increasing economical and societal relevance.
KW - Enzymatic degradation
KW - Poly(L‑lactide)
KW - Polyesters
KW - biodegradation
PY - 2022
DO - https://doi.org/10.1021/acs.biomac.2c01008
SN - 1525-7797
SN - 1526-4602
VL - 23
IS - 11
SP - 4841
EP - 4850
PB - ACS Publications
AN - OPUS4-56292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guerra, E. S. S.
A1 - Silva, B. L.
A1 - Melo, J. D. D.
A1 - Kalinka, Gerhard
A1 - Barbosa, A. P. C.
T1 - Microscale evaluation of epoxy matrix composites containing thermoplastic healing agent
N2 - Among the strategies to produce healable thermosetting systems is their modification by the addition of thermoplastic particles. This work investigates the influence of poly(ethylene-co-methacrylic acid) (EMAA) on fibermatrix interfacial properties of a glass fiber reinforced epoxy matrix composite. Epoxy-EMAA interactions were evaluated using differential scanning calorimetry (DSC) and infrared spectroscopy. The effects of EMAA on the epoxy network formation were evidenced by changes in glass transition temperature, cure kinetics and alteration of chemical groups during cure. Interfacial shear strength (IFSS) measurements obtained by single fiber pull-out tests indicate similar interfacial properties for pure and EMAA modified epoxy. Additionally, the potential for self-healing ability of an EMAA modified epoxy was demonstrated. However, IFSS after a healing cycle for the EMAA modified epoxy was lower as compared to the pure epoxy, because of the lower fiber-EMAA interfacial shear strength. So, thermoplastic healing agents has not only to fill cracks in the matrix material, but also have to be optimized regarding its interface properties to the reinforcing fibers.
KW - Interfacial strength
KW - Fiber/matrix bond
KW - Self-healing
KW - Polymer-matrix composites (PMC)
PY - 2022
DO - https://doi.org/10.1016/j.compscitech.2022.109843
SN - 0266-3538
VL - 232
SP - 1
EP - 9
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-56379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hertwig, Andreas
A1 - Ermilova, Elena
T1 - Optical constants of a single AlN layer on Si
N2 - Spectroscopic ellipsometry was used to determine the thickness and dielectric function of a Aluminium Nitride (AlN) layer on a Si wafer. The layer was determined to be 170 nm thick. The layer was provided by AIXTRON and manufactured by means of MOVPE.
The data was created using a M2000DI spectroscopic ellipsometer from Woollam Co. Inc. Analysis was done using the CompleteEASE software. The model used is a multi-peak oscillator model for the AlN layer.
The data resembles common database values for the material AlN.
KW - Aluminium nitride
KW - Thin solid layers
KW - Spectroscopic ellipsometry
KW - Compund semiconductors
KW - MOVPE
PY - 2024
UR - https://zenodo.org/records/12743500
DO - https://doi.org/10.5281/zenodo.12743499
PB - Zenodo
CY - Geneva
AN - OPUS4-60661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bordeenithikasem, Punnathat
A1 - Carpenter, Kalind C.
A1 - Hofmann, Douglas C.
A1 - White, Victor E.
A1 - Yee, Karl Y.
A1 - Rizzardi, Quentin
A1 - Maher, Jacob
A1 - Maaß, Robert
T1 - Miniaturized bulk metallic glass gripping structures for robotic mobility platforms
N2 - Advancements in bulk metallic glass thermoplastic forming unleash the potential to fabricate microscale metallic features with unparalleled precision and durability, i.e. microspine gripping structures for mobility platforms on planetary or in-space robots. Four designs of grippers were fabricated and rigorously tested. Coefficient of friction on four test surfaces were measured and compared to SiC paper and Velcro. The hardness and elasticity of the bulk metallic glasses make them a game-changer in the field, offering a superior alternative to conventional nonmetallic grippers.
KW - Bulk metallic glasses
KW - Thermoplastic forming
KW - Mobility
KW - Microspine
PY - 2024
DO - https://doi.org/10.1016/j.actaastro.2024.03.040
SN - 0094-5765
VL - 219
SP - 399
EP - 407
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-60182
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
T1 - Merkmale von alltäglichen Brüchen und wie wir daraus lernen können
N2 - Schadensfälle aus dem Alltag erscheinen oft simpel, sind im Detail aber meist komplexer als erwartet und eröffnen die Möglichkeit, Merkmale zu studieren, Aufnahmetechniken und Bildbearbeitung zu optimieren und die Erfahrungen am Ende ohne Restriktionen weiter zu vermitteln. Beispielsweise verändern sich die mikroskopischen Merkmale von Schwingrissen über ihren Verlauf oft deutlich. Dies hängt von der Art des Werkstoffs und von den Beanspruchungsbedingungen ab. Die Bruchmerkmale werden schließlich systematisch dargestellt und ein Datensatz für die Fraktographische online-Datenbank der DVM/DGM AG Fraktographie erstellt, die fachöffentlich einsehbar ist.
T2 - Metallographietagung 2024
CY - Berlin, Germany
DA - 18.09.2024
KW - Fraktographie
KW - Schadensanalyse
PY - 2024
AN - OPUS4-61239
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völker, Christoph
A1 - Kruschwitz, Sabine
A1 - Moreno Torres, Benjami
A1 - Firdous, R.
A1 - Zia, G. J. A.
A1 - Stephan, D.
T1 - Accelerating the search for alkali-activated cements with sequential learning
N2 - With 8% of man-made CO2 emissions, cement production is an important driver of the climate crisis. By using alkali-activated binders, part of the energy-intensive clinker production process can be dispensed. However, as numerous raw materials are involved in the manufacturing process here, the complexity of the materials increases by orders of magnitude. Finding a properly balanced binder formulation is like looking for a needle in a haystack. We have shown for the first time that artificial intelligence (AI)-based optimization of alkali-activated binder formulations can significantly accelerate research.
The "Sequential Learning App for Materials Discovery" (SLAMD) aims to accelerate practice transfer. With SLAMD, materials scientists have low-threshold access to AI through interactive and intuitive user interfaces. The value added by AI can be determined directly. For example, the CO2 emissions saved per ton of cement can be determined for each development cycle: the more efficient the AI optimization, the greater the savings.
Our material database already includes more than 120,000 data points of alternative binders and is constantly being expanded with new parameters. We are currently driving the enrichment of the data with a life cycle analysis of the building materials.
Based on a case study we show how intuitive access to AI can drive the adoption of techniques that make a real contribution to the development of resource-efficient and sustainable building materials of the future and make it easy to identify when classical experiments are more efficient.
T2 - fib International Congress
CY - Oslo, Norway
DA - 12.06.2022
KW - Concrete
KW - Materials Design
KW - Sequential Learning
KW - Machine Learning
PY - 2022
SP - 1
EP - 9
AN - OPUS4-56634
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - KorroPad - Vom Schadensphänomen zur Prüfmethode für Forschung und betriebliche Anwendung
N2 - Eine Erfolgsgeschichte von der praktischen Umsetzung von Forschungsergebnissen für Entwicklung einer Prüfmethode.
T2 - GfKORR Jahrestagung - Aktuelles aus der Korrosionsforschung - Nutzen und praktische Anwendungen
CY - Frankfurt a. M., Germany
DA - 08.11.2022
KW - Korrosion
KW - Nichtrostender Stahl
KW - KorroPad
KW - Korrosionsprüfung
PY - 2022
AN - OPUS4-56204
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schraa, Lucas
A1 - Rodricks, Carol
A1 - Kalinka, Gerhard
A1 - Roetsch, Karl
A1 - Scheffler, Christina
A1 - Sambale, Anna
A1 - Uhlig, Kai
A1 - Stommel, Markus
A1 - Trappe, Volker
T1 - Characterisation and Modelling of the Fibre-Matrix Interface of Short Fibre Reinforced Thermoplastics using the Push-Out Technique
N2 - This study investigates the suitability of the single fibre push-out (SFPO) test for the determination of the interfacial shear strength (IFSS) of injection moulded short fibre reinforced thermoplastics. It includes a detailed description of the required sample preparation steps and the boundary conditions of the SFPO setup. Experimental SFPO tests were carried out on PA66 GF, PPA GF35 and PA6 GF50 materials. Furthermore, a finite element model was set up to simulate the behaviour of these materials during this test. The numerical results showed that the inhomogeneous stress distribution in the fibre-matrix interphase during the test causes the measured apparent IFSS to underestimate the true strength of the interphase. The simulations put the experimental results into perspective and provide valuable information for the further development of the test setup. This study therefore not only provides new insights into the interphase strength of injection moulded short fibre reinforced thermoplastics, but also an insight into local load conditions during testing and thus an indication of the true IFSS.
KW - GFRP
KW - Interface
KW - fibre matrix bond
KW - single fibre push-out
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626087
DO - https://doi.org/10.1016/j.compositesb.2025.112317
SN - 1879-1069
VL - 297
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-62608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
T1 - The use of effective fatigue crack propagation data obtained at closure-free conditions for component assessment
N2 - The knowledge of fatigue crack propagation data in terms of their effective values is important for a conservative and safe life assessment of components subjected to cyclic loading. To overcome issues related to the precise consideration of the crack-closure effects on experimental data obtained at small R ratios, closure-free data have been obtained at R ≈ 0.8 by different experimental procedures. The statistical analysis of the intrinsic fatigue crack propagation threshold obtained experimentally has shown a small data scatter and good agreement between procedures. When compared with effective values obtained from analytical corrections of closure-affected data, the data obtained at R ≈ 0.8 should lead to a conservative life estimation.
T2 - 43rd International Conference on Materials Mechanics
CY - Sani, Greece
DA - 05.06.2022
KW - Component assessment
KW - Effective crack propagation data
KW - Experimental procedure
KW - Crack-closure
PY - 2022
SP - 104
EP - 108
AN - OPUS4-56851
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Drago, Claudia
T1 - Sweetening the (microplastics) pill: PET tablets (1-100µm) as candidate reference material for the validation of microplastics measurement
N2 - The lack of validation and standard procedures in microplastics studies has led to the inability to compare and harmonise data from different analytical methods, laboratories and time scales. To monitor and regulate exposure to microplastics in the environment and in food for human health, it is crucial to ensure their comparability and to validate the analytical methods used in microplastics studies.
Monitoring microplastics requires complex approaches for accurate determination otherwise it can lead to an over- or underestimation in environmental and food-relevant matrices. Moreover, to support the need of reliable measurement required by the European legislation directive on drinking water (EU 2020/2184) or the revision of the urban waste water directive, which will be finalised in 2024 the production and validation of polymeric reference materials with environmentally relevant concentrations, irregular shapes, defined aging status and different sizes is essential. The production of reference material with acceptable uncertainties in homogeneity need to be balanced, considering the low microplastics concentrations detected in the environment and in food.
The aim of the project PLASTICTRACE and of this study, is to propose a “easy-to-use PET tablet ” (PET particle size mainly 1-100 µm) for routine applications as a candidate general reference material for detection methods. Batches of water-soluble matrix containing different concentrations of PET powder were produced.
Results of imaging and counting methods (SEM, Laser diffraction), including production´s challenges; together with thermo-analytical methods (TED-GC/MS and Py-GC/MS) and vibrational spectroscopy (µ-Raman and µ-FTIR), will be presented. These data are useful to assess homogeneity and stability of the particles over time according to ISO 33405:2024.
In addition, we will show some insights on the application of the PET-tablets in complex matrices, as milk powder and suspended solid from surface water, that could be easily used for routine microplastics analysis.
T2 - MICRO 2024
CY - Arrecife, Spain
DA - 23.09.2024
KW - Microplastics
KW - Reference materials
KW - Polymer 3R
KW - TED-GC/MS
PY - 2024
AN - OPUS4-61274
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte Bernardino, Carolina
A1 - Lee, Mihyun
A1 - Ren, Qun
A1 - Ruehle, Bastian
T1 - Facile Spray-Coating of Antimicrobial Silica Nanoparticles for High-Touch Surface Protection
N2 - The rising threat from infectious pathogens poses an ever-growing challenge. Metal-based nanomaterials have gained a great deal of attention as active components in antimicrobial coatings. Here, we report on the development of readily deployable, sprayable antimicrobial surface coatings for high-touch stainless steel surfaces that are ubiquitous in many healthcare facilities to combat the spread of pathogens. We synthesized mesoporous silica nanoparticles (MSNs) with different surface functional groups, namely, amine (MSN-NH2), carboxy (MSN-COOH), and thiol groups (MSN-SH). These were chosen specifically due to their high affinity to copper and silver ions, which were used as antimicrobial payloads and could be incorporated into the mesoporous structure through favorable host−guest interactions, allowing us to find the most favorable combinations to achieve antimicrobial efficacy against various microbes on dry or semidry high-touch surfaces. The antimicrobial MSNs were firmly immobilized on stainless steel through a simple two-step spray-coating process. First, the stainless steel surfaces are primed with sprayable polyelectrolyte solutions acting as adhesion layers, and then, the loaded nanoparticle dispersions are spray-coated on top. The employed polyelectrolytes were selected and functionalized specifically to adhere well to stainless steel substrates while at the same time being complementary to the MSN surface groups to enhance the adhesion, wettability, homogeneity, and stability of the coatings. The antimicrobial properties of the nanoparticle suspension and the coatings were tested against three commonly found pathogenic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, as well as a fungal pathogen, Candida albicans. Especially MSN-SH loaded with silver ions showed excellent antimicrobial efficacy against all tested pathogens under application-relevant, (semi)dry conditions. The findings obtained here facilitate our understanding of the correlation between the surface properties, payloads, and antimicrobial activity and show a new pathway toward simple and easily deployable solutions to combat the spread of pathogens with the help of sprayable antimicrobial surface coatings.
KW - Mesoporous silica nanoparticles
KW - Thin films
KW - Antimicrobial coatings
KW - Spray-coating
KW - Infectious diseases
KW - Pathogen transmission
KW - High-touch surfaces
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626269
DO - https://doi.org/10.1021/acsami.4c18916
SN - 1944-8252
SP - 1
EP - 13
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-62626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bulling, Jannis
A1 - Jurgelucks, B.
A1 - Prager, Jens
A1 - Walther, A.
T1 - Modellierung und Validierung eines inversen Verfahrens zur Schadensrekonstruktion mittels Lamb-Wellen im Ultraschallbereich
N2 - Das Ausbreitungsverhalten geführter Ultraschallwellen ermöglicht die großflächige Prüfung von Platten und schalenförmigen Bauteilen wie Rohren und Laminaten auf Fehlstellen von wenigen Prüfpunkten aus. Während die beschränkte Divergenz der geführten Wellen die Ultraschallprüfung begünstigt, erschwert das dispersive und multimodale Verhalten der Lamb-Wellen die Auswertung der Ultraschallsignale. Die dispersive und multimodale Wellenausbreitung verkompliziert die Bestimmung der Fehlerposition bei der Auswertung der Geschwindigkeiten einzelner Wellenpakete. Zudem ist es herausfordernd, einen einfachen Zusammenhang zwischen den Reflexionen der Fehlstelle und deren Größe und Form herzustellen. Eine Möglichkeit zur genauen Bestimmung der Fehlerposition und -geometrie bietet der direkte Vergleich der Messsignale mit den Signalen aus einem Simulationsmodell. Die Nachbildung des Schadens im Simulationsmodell stellt ein inverses Problem dar, das iterativ gelöst werden kann, indem ein Vorwärtsmodell immer weiter optimiert wird. Klassische Ansätze wie die Finite Elemente Methode (FEM) sind für die Simulation von Ultraschallwellen aufgrund der kleinen Wellenlängen im Vergleich zur Bauteilgröße meist ineffizient. Aus diesem Grund basiert das vorgestellte Vorwärtsmodell auf der semi-analytischen Scaled Boundary Finite Element Method (SBFEM), die große Teile der Wellenausbreitung analytisch berechnet. In diesem Beitrag wird die Validierung des zweidimensionalen Modells an Platten mit einer rechteckigen Nut als Ersatzfehler präsentiert und es werden erste Schritte zur Validierung von 3D-Modellen vorgestellt.
T2 - DAGA 2024
CY - Hannover, Germany
DA - 18.03.2024
KW - Geführter Ultraschall
KW - Inverse Verfahren
KW - SBFEM
PY - 2024
UR - https://www.dega-akustik.de/publikationen/online-proceedings
SP - 644
EP - 647
AN - OPUS4-60212
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kalinka, Gerhard
T1 - Moderne Faserverbundwerkstoffe – Reparatur und Recycling
N2 - Der Vortrag beschreibt Aktivitäten der BAM zur Reparatur von Rotorblättern von Windkraftanlagen sowie ein Konzept zum Recycling by Design für faserverstärkte Kunststoffe
T2 - Reparaturgerechtes Produktdesign
CY - Potsdam, Germany
DA - 06.11.2024
KW - GFRP
KW - Rotorblätter
KW - Reparatur
KW - Recycling
KW - Composites
PY - 2024
AN - OPUS4-61533
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishmastnehi, Moslem
A1 - Stawski, Tomasz M.
A1 - Eftekhari, Negar
A1 - Schneider, Kathrin P.
A1 - Vaccaro, Carmela
A1 - Aghajani, Iman
A1 - Grbanovic, Ana Marija
A1 - Korn, Lorenz
T1 - Unveiling the craftsmanship and knowledge behind iranian stuccoes (11th–14th centuries): New insights from an archaeometric perspective
N2 - Gypsum-based stucco decorations of 47 monuments in Iran, from the Seljuq to the Ilkhanid period (11th-14th centuries), were studied by multimodal analytical methods, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy and image analysis to evaluate their composition properties. The assessment of results shows that stucco masters in those periods exerted control over the setting process of the gypsum-paste and its microstructure by adjusting water-to-plaster ratio, fine-clay addition, and by means of mechanical processing. Furthermore, the presence of anhydrite in the composition of stucco decorations located in the hot-desert climate of Iran provides evidence for the probability of gypsum-anhydrite transition, which has technical and preservation consequences for this less-investigated type of cultural materials.
KW - Gypsum
KW - Diffraction
KW - Anhydrite
KW - Calcium sulfate
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628406
DO - https://doi.org/10.1016/j.jas.2025.106199
SN - 1095-9238
VL - 177
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-62840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seilert, J.
T1 - (Re)engineering functional fat phases – bridging industry and ivory tower
N2 - The crystallization kinetics of commercial structuring fats are determined by the interplay of polymorphic transitions and the formation of mixed crystals involving three primary melting groups: H3, H2M, and H2U. Here, H represents long-chain saturated fatty acids, M denotes medium-chain saturated fatty acids, and U signifies unsaturated fatty acids. Assigning the molecular makeup of structuring fats to the kinetic pathways proves to be a challenging task when dealing with complex mixtures. For example, incorporating H2M triglycerides alters the crystallization pathways substantially by impacting the formation of mixed crystals with and between H3 and H2U triglycerides (TAGs). However, determining the impact of specifics in molecular composition, e.g., fatty acid content and TAG asymmetry, remains a complex challenge when dealing with intricate mixtures. This might be overcome by targeting distinct melting groups and comparing their behavior in complex mixtures to academic replicates.
This study examined four commercial blends with different fatty acids (palmitic versus stearic acid) and varying H3 contents (8% versus 4%), C8-P, C8-S, C4-P, and C4-S. The H2M content and sum of structuring melting groups was kept constant at 9 % and 25 %, respectively. Further, the commercial blends were replicated using synthetic triglycerides representing the main melting groups: PPP and SSS for H3, PLaP and SLaS for H2M and POP and SOS for H2U – resulting in academic blends A8-P, A8-S, A4-P, and A4-S. The crystallization under quiescent conditions at a cooling rate of 3.5 K/min of all eight blends was studied via DSC and time-resolved SAXS/WAXS.
While the P-based commercial blends (C8-P and C4-P) followed typical crystallization routes including an α-β’ transition and clear dependency on H3 content, the S-based counterparts, C8-S and C4-S, showed an α-phase of prolonged stability and evidence of two distinct β’ phases. Differences between commercial and academic blends are discussed.
T2 - 2nd Berlin Symposium on Structured Lipid Phases
CY - Berlin, Germany
DA - 30.09.2024
KW - Lipid phases
KW - Thermal structuring
KW - Crystallography
KW - X-ray scattering
PY - 2024
AN - OPUS4-61334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kalinka, Gerhard
T1 - Recycling von Faserverbundwerkstoffen
N2 - Der Vortrag beschreibt Aktivitäten der BAM zum Recycling von carbonfaser-verstärkten Verbundwerkstoffen.
T2 - Fachdialog Recycling von Windenergieanlagen
CY - Berlin, Germany
DA - 23.09.2024
KW - Polymer Matrix Composite
KW - Carbon Fibres
KW - Recycling
KW - Pyrolysis
KW - Recycling by Design
PY - 2024
AN - OPUS4-61536
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hadley, I.
A1 - Zerbst, Uwe
A1 - Coules, H.
A1 - James, P.
A1 - Sharples, J.
A1 - Bath, S.
A1 - Larrosa, N.
T1 - Knowledge gaps in fitness-for-service assessment procedures; summary of the 2nd ‘mind the gap’ workshop
N2 - In 2015, the University of Manchester hosted a workshop (‘Mind the Gap’) aimed at identifying gaps in a number of structural integrity fitness-for-service procedures, including R5, R6, BS 7910 and API/ASME. The findings were subsequently summarised in a journal paper and shared with the relevant stakeholders. A second workshop, this time hosted by the University of Bristol in 2017, was intended to build on the findings of the earlier event, identifying which gaps had been filled, which remain and whether new ones have been identified in the meantime. ‘Mind the Gap 2’ was wide-ranging, including consideration of failure by fracture, fatigue crack growth, hightemperature creep and environmentally assisted crack growth, along with the use of innovative techniques to follow the progress of crack growth from the atomic to the macroscopic scale. A summary of the whole event is thus outside the scope of a single paper, so here we concentrate mainly on advances in fracture assessment, on the interface between inspection and ECA, and on how developments are being incorporated into structural integrity procedures. There is a particular emphasis on the energy transition in the UK, where the planned energy mix will include both nuclear power and offshore wind.
KW - Flaw assessment procedures
KW - Non-sharp defects
KW - Flaw interaction
KW - Codes and standards
KW - Nuclear reactor systems
PY - 2023
DO - https://doi.org/10.1016/j.ijpvp.2022.104883
SN - 0308-0161
VL - 202
SP - 1
EP - 14
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-56846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Temperature in micromagnetism: Cell size and scaling effects of the stochastic Landau-Lifshitz equation
N2 - The movement of the macroscopic magnetic moment in ferromagnetic systems can be described by the Landau-Lifshitz (LL) or Landau-Lifshitz-Gilbert (LLG) equation. These equations are strictly valid only at absolute zero temperature. To include temperature effects a stochastic version of the LL or LLG equation for a spin density of one per unit cell can be used instead. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion regarding simulation cell size and temperature has to be established. Based on energetic considerations, a conversion for ferromagnetic bulk and thin film systems is proposed. The conversion is tested in micromagnetic simulations which are performed with the Object Oriented Micromagnetic Framework (OOMMF). The Curie temperatures of bulk Nickel, Cobalt and Iron systems as well as Nickel thin-film systems with thicknesses between 6.3 mono layer (ML) and 31ML are determined from micromagnetic simulations. The results show a good agreement with experimentally determined Curie temperatures of bulk and thin film systems when temperature scaling is performed according to the presented model.
T2 - #RSCposter 2023
CY - Online meeting
DA - 28.02.2023
KW - Exchange interaction
KW - Ferromagnetism
KW - LLG
KW - Landau Lifshitz equation
KW - Magnetic moment
KW - Magnetic nanoparticles
KW - Micromagnetism
KW - OOMMF
KW - Object oriented micromagnetic framework
KW - Stochastic Landau Lifshitz Gilbert equation
KW - Temperature scaling
PY - 2023
AN - OPUS4-57062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tang, Chi-Long
T1 - Sub-4 nm particles from FFF-3D printing measured with the TSI 1 nm CPC and the Airmodus A11 nCNC
N2 - Concerns have been raised as Fused Filament Fabrication (FFF) desktop 3D printer emits harmful ultrafine particles (dP < 100 nm) during operation in indoor spaces. However, the vast majority of previous emission studies have neglected the possible occurrence of sub-4 nm particles by using conventional condensation particle counter (CPC) for detection. Thus, the total particle emission could be systematically underestimated. This study has compared two diethylene glycol (DEG) based instruments to evaluate their suitability for measuring organic FFF particles in the sub-4 nm size range either as particle counter or as a particle size spectrometer.
T2 - European Aerosol Conference 2024
CY - Tampere, Finland
DA - 25.08.2024
KW - Air pollution
KW - Emission testing
KW - FFF-3D printing
KW - Sub-4nm particles
KW - Ultrafine particles
PY - 2024
AN - OPUS4-60930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Junge, Paul
A1 - Rupprecht, Christian
A1 - Sänger, Johanna
A1 - Oedinghofen, Frank
T1 - Thermisch gespritzte Schichten auf keramischen Hitzeschutzschilden für den Einsatz regenerativer Brennstoffe in stationäre Gasturbinen
T1 - Thermally sprayed coatings on ceramic heat shields
for the utilisation of regenerative fuels in stationary gas turbines
N2 - Die Entwicklung zukünftiger Generationenvon stationären Gasturbinen verfolgt das Hauptziel, den thermischen Wirkungsgrad zu erhöhen, bei gleichzeitiger Reduktion der CO2-Emissionen. Ein mögliches Lösungskonzept besteht darin, bestehende Turbinenkonzepte auf nachhaltig erzeugten Wasserstoff umzustellen. Durch den Betrieb mit Wasserstoff entsteht eine erhöhte Belastung für konventionelle thermische Hitzeschutzkomponenten. Daher ist die Entwicklung von sogenannte Environmental Barrier Coatings (EBC) oder Materialkonzepten, die eine thermodynamische Stabilität in heißer Gasumgebung aufweisen, erforderlich.
N2 - The development of future generations of stationary gas turbines is
pursuing the main objective of increasing the thermal efficiency, with a simultaneous reduction in the CO2 emissions. One possible solution concept consists of converting existing turbine concepts to sustainably produced hydrogen. The operation with hydrogen results in increased loads for conventional thermal heat protection components. Therefore, it is necessary to develop so-called environmental barrier coatings (EBCs) or material concepts which exhibit thermodynamic stability in a hot gas environment
KW - Keramischen Hitzeschutzschilden
KW - Thermische Spritzschichten
KW - Gasturbine
PY - 2024
UR - https://www.thermal-spray-bulletin.info/en/article/thermisch-gespritzte-schichten-auf-keramischen-hitzeschutzschilden-fuer-den-einsatz-regenerativer-brennstoffe-in-stationaeren-gasturbinen
IS - 2
SP - 100
EP - 103
PB - DVS Media
AN - OPUS4-61066
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Semantic integration of diverse data in materials science: Assessing Orowan strengthening
N2 - This study applies Semantic Web technologies to advance Materials Science and Engineering (MSE) through the integration of diverse datasets. Focusing on a 2000 series age-hardenable aluminum alloy, we correlate mechanical and microstructural properties derived from tensile tests and darkfield transmission electron microscopy across varied aging times. An expandable knowledge graph, constructed using the Tensile Test and Precipitate Geometry Ontologies aligned with the PMD Core Ontology [1], facilitates this integration. This approach adheres to FAIR principles and enables sophisticated analysis via SPARQL queries, revealing correlations consistent with the Orowan mechanism (see Fig.1). The study highlights the potential of semantic data integration in MSE, offering a new approach for data-centric research and enhanced analytical capabilities [2].
T2 - MSE Congress 2024 - Materials Science and Engineering
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Semantic Representation
KW - Age-Hardenable Aluminium Alloy
KW - Digtial Representation
KW - Knowledge graph and ontologies
KW - PMD Core Ontology
PY - 2024
AN - OPUS4-61139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kempf, A.
A1 - Hilgenberg, Kai
T1 - Influence of sub-cell structure on the mechanical properties of AlSi10Mg manufactured by laser powder bed fusion
N2 - AlSi10Mg is one of the most applied alloys for laser powder bed fusion (LPBF) technology, due to its great possibilities for implementing new lightweight concepts such as in automotive industries. For the component design it is necessary to know about the mechanical properties and the mechanical behaviour. The many published strength properties of LPBF processed AlSi10Mg show significant differences up to approximately 225 MPa in ultimate tensile strength (UTS) and 195 MPa in yield strength (YS). To understand these varying properties, a ring trial was carried out manufacturing specimens on 6 LPBF machines with different parameters and build-up strategies. They were studied in the as-built (AB) condition and after heat treatment at 300 °C for 30 min, respectively. For examining the mechanical properties, tensile tests and hardness measurements were carried out. The microstructure was characterized by optical light microscopy (OM), field emission scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). The identified differences in strength properties were discussed based on the 4 strengthening mechanism known for metallic materials and at the background of material defects. It was found that the size of the typical sub-cell structure of LPBF AlSi10Mg affected substantially the mechanical properties in the AB condition, in which with decreasing sub-cell size strength increased. If heat treatment was applied, the strength properties decreased and did not differ anymore. Since annealing led to coarsened sub-cells, whereas the grains itself did not change in size, the influence of sub-cell structure on strength was further confirmed. In addition, acicular precipitates in the AB condition were observed at specimens from one LPBF machine showing the lowest tensile elongation.
KW - Laser powder bed fusion
KW - AlSi10Mg
KW - Mechanical properties
KW - Microstructure
PY - 2020
DO - https://doi.org/10.1016/j.msea.2020.138976
VL - 776
SP - Paper 138976, 12
PB - Elsevier B.V.
AN - OPUS4-50316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erning, Johann Wilhelm
A1 - Kamaraj, A.
T1 - Susceptibility of 304 Stainless Steel to Crevice Corrosion in Electrochemically Active Fluids
N2 - The susceptibility of Type 304 stainless steel (SS) to crevice corrosion upon contacting with electrochemically active fluids was investigated using exposure tests and stepwise potentiostatic polarization. Crevice materials made of 304 SS and polyether ether ketone (PEEK) were focused on in this study. The combined influence of oxidant and chloride concentration on crevice corrosion was examined in detail in the two types of crevice combinations (304 SS-to-PEEK and 304 SS-to-304 SS). The 304 SS specimens were strongly susceptible to crevice corrosion when coupled with 304 SS. Even at a low concentration of 5 mg/L free chlorine and 150 mg/L chloride, which is below nominal dilutions in beverage industries, the examined specimens underwent crevice corrosion in both crevices. The effect of water composition on crevice corrosion was also studied, indicating high susceptibility of 304 SS to crevice corrosion in low pH (pH ≤ 5) solutions. The corroded surface morphology was analyzed using scanning electron microscope, energy dispersive x-ray, and confocal.
KW - Crevice corrosion
KW - Disinfectants
KW - Stainless steel
PY - 2020
DO - https://doi.org/10.5006/3324
SN - 0010-9312
VL - 76
IS - 4
SP - 424
EP - 435
PB - Nace International
CY - Houston
AN - OPUS4-50652
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheffler, F.
A1 - Tielemann, Christopher
T1 - Crystallization of glasses studied with PEEM
N2 - A heat treated glass that formed crystals under controlled conditions can be a glass ceramic. A proper understanding of crystallization in glassy melts is needed yet still lacking. Involved processes include the mobility of Elements within the glass during heat treatment and the reorganization of atomic bonds during crystallization. This change in coordination number of certain elements is easily observable in bulk glass samples during heat treatment with XAS. Our plan was to monitor these reorganization processes in situ at the immediate surface during heat treatment with PEEM to get time and spatial resolved data.
T2 - Joint Meeting of the Polish Synchrotron Radiation Society and SOLARIS Users
CY - Online meeting
DA - 09.09.2020
KW - Glass
KW - Surface
KW - Peem
KW - Synchrotron
PY - 2020
AN - OPUS4-51336
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Babutzka, Martin
T1 - Neue Erkenntnisse zur Deckschichtbildung von Zink an der Atmosphäre
N2 - Die Korrosionsbeständigkeit und die Dauerhaftigkeit von Zink und Zinküberzügen an der Atmosphäre sind direkt mit der Bildungs- und Auflösungskinetik von schützenden Deckschichten aus festhaftenden Korrosionsprodukten verknüpft. Bei einem optimalen Zusammenwirken und einer günstigen Abfolge von atmosphärischen Einflussfaktoren bilden sich gut schützende, bei Feuchtigkeitszutritt nahezu unlösliche Deckschichten aus. Art und Eigenschaften der gebildeten Deckschichten hängen dabei insbesondere von den Luftinhaltsstoffen der Einsatzumgebung sowie von spezifischen Temperatur-Feuchte-Zyklen ab. Dabei besteht das Problem, dass sich die klimatischen Bedingungen und infolge auch die Deckschichtbildungsreaktionen bei Zink an der Atmosphäre im Laufe der letzten Jahrzehnte stark geändert haben.
Das Ziel der vorliegenden Arbeit ist die systematische Untersuchung und Beschreibung von Korrosions- und Deckschichtbildungsvorgängen bei Reinzink unter den aktuell in der Bundesrepublik Deutschland vorherrschenden klimatischen Bedingungen. Die Untersuchungen zielen in ihrer Gesamtheit auf das Hinterfragen aktueller und die Etablierung neuer Betrachtungsweisen zur Deckschichtbildung bei Reinzink unter atmosphärischen Korrosionsbedingungen ab und sollen damit einen wesentlichen Beitrag für das Verständnis des Korrosionsschutzes durch Zink und Zinküberzüge liefern. Dabei wurde der Fokus insbesondere auf das Anfangsstadium der Deckschichtbildung gelegt. Eine systematische Untersuchung dieses Zeitraums, der von sehr reaktiven Deckschichten geprägt ist, wurde erst durch den gezielten Einsatz gelartiger Elektrolyte ermöglicht.
KW - Zink
KW - Korrosion
KW - Deckschichtbildung
KW - Atmosphäre
KW - gelartige Elektrolyte
PY - 2020
SN - 978-3-8440-7626-4
DO - https://doi.org/10.2370/9783844076264
SN - 0945-1056
SP - 1
EP - 181
PB - Shaker Verlag
CY - Düren
AN - OPUS4-51458
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Ralf
A1 - Waurischk, Tina
A1 - Behrens, H.
A1 - Deubener, J.
T1 - Crack growth in borate and silicate glasses: Stress-corrosion susceptibility and hydrolytic resistance
N2 - A double cantilever beam technique in air equipped with ultrasound modulation was used to measure the crack velocity v in borate and silicate glasses. In all glasses v and the stress intensity KI followed the empirical correlation v ~ KIn. Indicated by its smallest KI at v = 1 μm s − 1, KI* = 0.27 MPa m0.5, the silicoborate glass containing 70 mol% B2O3 was found most susceptible to stress-corrosion enhanced crack growth. Contrarily, the sodium calcium magnesium silicate glass appeared least susceptible with KI* = 0.57 MPa m0.5. No clear correlation is evident between KI*, reflecting the stress-corrosion susceptibility, and the hydrolytic resistance for all glasses under study, but values of n obtained from the present study and taken from previous literature for 35 glasses tend to decrease with increasing network modifier ion fraction. Energy dissipation during stress-corrosion enhanced crack propagation is assumed to cause this trend.
KW - DCB
KW - Alkali and alkaline earth silicate and borate glass
KW - Crack growth in air
KW - Stress-corrosion
KW - Stress intensity
PY - 2021
DO - https://doi.org/10.1016/j.jnoncrysol.2020.120414
VL - 551
SP - 120414
PB - Elsevier B.V.
AN - OPUS4-51393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hensel, J.
A1 - Kromm, Arne
A1 - Nitschke-Pagel, T.
A1 - Dixneit, Jonny
A1 - Dilger, K.
T1 - Capability of martensitic low transformation temperature welding consumables for increasing the fatigue strength of high strength steel joints
N2 - The use of low transformation temperature (LTT) filler materials represents a smart approach for increasing the fatigue strength of welded high strength steel structures apart from the usual procedures of post weld treatment. The main mechanism is based on the effect of the low start temperature of martensite formation on the stress already present during welding. Thus, compressive residual stress formed due to constrained volume expansion in connection with phase transformation become highly effective. Furthermore, the weld metal has a high hardness that can delay the formation of fatigue cracks but also leads to low toughness. Fundamental investigations on the weldability of an LTT filler material are presented in this work, including the characterization of the weld microstructure, its hardness, phase transformation temperature and mechanical properties. Special attention was applied to avoid imperfections in order to ensure a high weld quality for subsequent fatigue testing. Fatigue tests were conducted on the welded joints of the base materials S355J2 and S960QL using conventional filler materials as a comparison to the LTT filler. Butt joints were used with a variation in the weld type (DY-weld and V-weld). In addition, a component-like specimen (longitudinal stiffener) was investigated where the LTT filler material was applied as an additional layer. The joints were characterized with respect to residual stress, its stability during cyclic loading and microstructure. The results show that the application of LTT consumables leads to a significant increase in fatigue strength when basic design guidelines are followed. This enables a benefit from the lightweight design potential of high-strength steel grades.
KW - Low transformation temperature
KW - Welding
KW - Fatigue strength
KW - Residual stress
PY - 2020
DO - https://doi.org/10.3139/120.111562
VL - 62
IS - 9
SP - 891
EP - 899
PB - Carl Hanser Verlag
AN - OPUS4-51180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Hamm, C.
A1 - Röser, T.
A1 - Michels, H.
T1 - Vom Kokillenguss bis zur Fräsbearbeitung - Bauteile aus innovativen Eisen- und Titanaluminiden wirtschaftlich herstellen
N2 - Der Beitrag gibt einen kurzen Einblick in das gerade bewilligte ZIM-Vorhaben „Technologie und Werkzeuge für ultraschallunterstütztes Fräsen von Eisen- und Titan-Aluminid-Bauteilen (TeWuFeAl)“. In dem Vorhaben wird durch 2 KMU aus dem Bereichen der Werkzeugentwicklung (Wolf GmbH) und der Anwendung (AWB GmbH) sowie durch 2 Forschungsinstitute, Access e. V. und Bundesanstalt für Materialforschung und -prüfung (BAM), die Herstellbarkeit sicherheitsrelevanter Leichtbauteile aus FeAl und TiAl durch das besonders wirtschaftliche Kokillengussverfahren und die anschließende ultraschallunterstützte Zerspanung untersucht.
KW - Eisenaluminid
KW - Titanaluminid
KW - Kokillenguss
KW - Fräsbearbeitung
KW - Ultraschallunterstütztes Fräsen
KW - Oberflächenintegrität
PY - 2020
SP - 12
PB - Manufacturing Innovation Network e. V.
CY - Varel, Germany
AN - OPUS4-51593
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuchenbecker, Petra
T1 - Granulometry of Nano Powders - a Challenge Especially for the Dispersion Process
N2 - The use of increasingly finer starting powders up to nanopowders can also be observed in the field of ceramics. Their advantages consist, for example, in their lower activation energy, an increase in strength or unique optical properties. However, handling and characterization of the powders are much more difficult. The main reason for this is the very high adhesive forces between the particles and between particles and other surfaces, too. Therefore, submicron and even more so nanoparticles tend to agglomerate and their separation into primary particles during sample preparation prior to particle sizing is of particular challenge. A representative measurement sample is only obtained when it no longer contains agglomerates. The evaluation of the dispersion process and a decision on whether it was successful thus increases in importance for the reliability of the measurement results of particle sizing.
The presentation uses examples to show possible approaches and provides information on possible sources of error.
It is shown that successful granulometric characterisation of fine powders requires both an improved dispersion technique and very often an effective combination of two or more measurement methods.
KW - Agglomerates
KW - Nano-powder
KW - Dispersion process
PY - 2021
SN - 0173-9913
VL - 98
IS - 2
SP - 47
EP - 54
PB - Göller Verlag GmbH
CY - Baden-Baden
AN - OPUS4-52504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hübler, Daniela
A1 - Höhne, Patrick
A1 - Gradt, Thomas
T1 - Influence of TiC content on the tribological behavior of NbC-Ni-TiC cermets
N2 - Increasing demand for alternatives to tungsten carbide (WC) cemented carbides as cutting tools, due to the health risks of their wear products WO3 and Co3O4. Niobium carbide (NbC) has a high potential, due to its high wear resitance, high hot hardness and melting point (3520°C), and low solubility in iron alloys.
T2 - 23rd International Conference on Wear of Materials
CY - Online meeting
DA - 26.04.2021
KW - Niobium carbide (NbC)
KW - Cermets
KW - Tribological behavior
PY - 2021
AN - OPUS4-52560
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A. I.
A1 - Petrushin, N. V.
A1 - Svetlov, I. L.
A1 - Nolze, Gert
T1 - Model for Forecasting Temperature Dependence of γ/γ' Misfit in Heat-Resistant Nickel Alloys
N2 - An analytical model for forecasting the temperature dependence of γ/γ' misfit in heat-resistant nickel alloys is proposed. The model accounts for the concentration dependences of the periods of crystalline lattices of the γ and γ' phases (Vegard law), thermal expansion of the γ and γ' lattices, and dissolution of the γ' phase at high temperatures. Adequacy of calculations of misfit is confirmed by comparison with the results of measurements using methods of X-ray and neutron diffraction. The model is applied for development of a nickel alloy with positive misfit.
KW - Heat-resistant nickel alloys
KW - Dimensional mismatch of crystalline lattice periods (misfit)
KW - Microstructure evolution
PY - 2022
DO - https://doi.org/10.1134/S2075113322010105
SN - 2075-1133
VL - 13
IS - 1
SP - 7
EP - 16
PB - Springer
AN - OPUS4-54379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt-Grund, R.
A1 - Sturm, C.
A1 - Hertwig, Andreas
T1 - Ellipsometry and polarimetry - Classical measurement techniques with always new developments, concepts, and applications
N2 - Ellipsometry is a matured experimental method, whose roots reach back into the early phase of modern optics itself. It is often attributed to be invented by Paul Drude in the last decade of the 19th century, but similar techniques had already been applied for years before Drude started his work. With this Special Issue about ellipsometry and related techniques, we hope to bring more attention to this method and advance and propagate it to be used by a broader community. We have collected a good mixture of articles: some texts are more in the line of users’ tutorial and best practice guides; others are intended to show recent developments of the method. With this collection, we also hope to show the generally rapidly expanding possibilities of ellipsometry and polarimetry to draw attention of new users and previously unrelated communities to this valuable tool.
KW - Ellipsometry
KW - Polarimetry
KW - Surfaces
KW - Thin films
KW - Optical analysis
PY - 2022
DO - https://doi.org/10.1515/aot-2022-0025
SN - 2192-8584
SN - 2192-8576
VL - 11
IS - 3-4 (Topical issue: Ellipsometry)
SP - 57
EP - 58
PB - De Gruyter
CY - Berlin
AN - OPUS4-55467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement by Monte-Carlo based particle scattering Simulations
N2 - Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined.[1] Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented. [2] These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for ongoing experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au.
T2 - NALS 2022
CY - Santander, Spain
DA - 27.04.2022
KW - AuNP
KW - Beta decay
KW - beta particle
KW - Brachytherapy
KW - Cancer treatment
KW - Clustered nanoparticles
KW - DNA
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - LEE
KW - Livermore model
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - OH radical
KW - particle scattering
KW - Penelope model
KW - Radiation damage
KW - Radiation therapy
KW - Radiationtherapy
KW - Radioactive decay
KW - Radiolysis
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
PY - 2022
AN - OPUS4-54775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Schmidt-Grund, R.
ED - Sturm, C.
ED - Hertwig, Andreas
T1 - Topical issue: Ellipsometry
N2 - Ellipsometry is a matured experimental method, whose roots reach back into the early phase of modern optics itself. It is often attributed to be invented by Paul Drude in the last decade of the 19th century, but similar techniques had already been applied for years before Drude started his work. With this Special Issue about ellipsometry and related techniques, we hope to bring more attention to this method and advance and propagate it to be used by a broader community.
KW - Spectroscopy
KW - Ellipsometry
KW - Surfaces
KW - Thin films
KW - Advanced optics
KW - Optical measurement technology
PY - 2022
UR - https://www.degruyter.com/journal/key/aot/11/3-4/html#contents
SN - 2192-8584
SN - 2192-8576
VL - 11
IS - 3-4
SP - 47
EP - 147
PB - De Gruyter
CY - Berlin
AN - OPUS4-55468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Luminescent multifunctional nanostructures for sensing and theranostics applications
N2 - An overview of the work carried out at LEMAF - Laboratory of Spectroscopy of Functional Materials at IFSC/USP was given. The work presented focus on the design, production and functional characterization of multifunctional nanoparticles.
T2 - NANOANDES - Latin American School on Nanomaterials and Appllications
CY - Araraquara, SP, Brazil
DA - 10.10.2023
KW - Multifunctional nanoparticles
KW - Upconversion nanoparticles
KW - Quantum dots
KW - Noble metal nanoparticles
PY - 2023
AN - OPUS4-60363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
T1 - Advanced lightweight applications – recycling versus reliability and fossil energy footprint
N2 - Advanced light weight applications like aircrafts and wind turbine blades are made of fibre reinforced plastics (FRP) with continuous fibre reinforcement and must withstand a high thermo-mechanical cyclic loading. The quality of the fibre matrix interface has a high impact on the fatigue life and was continuously improved over the years since the 50th. The fatigue life of glass fibre reinforced plastics (GFRP) used in aircraft industry is 10 to 100 times higher compared to glass fibre non crimp fabrics used for wind turbine blades.
To assure a constant and reliable high quality and strength of reinforcement fibres, synthetic fibre production is state of the art (CF, GF). There is a need for recycling GFRP and CFRP waste due to the upcoming use. Pyrolysis and solvolysis are more expensive than the mechanical route however enable a more sustainable recycling. Natural fibres and recycled synthetic fibres have a high scatter in quality and strength. Hence it is a challenge to optimize the production / recycling processes to get a reliable quality for any demanding (second life) application.
Chemical routes for using renewables resources and recycling, is going to be a good approach especially for polymer-matrix systems to get 100% quality (back) compared to the state of the art.
Finally, a proper design, life-time extension and repair is preferable to recycling to keep the carbon footprint as low as possible.
T2 - 27. INTERNATIONALES DRESDNER LEICHTBAUSYMPOSIUM
CY - Dresden, Germany
DA - 13.06.2024
KW - Polymer Matrix Composites
KW - Carbon Fibre
KW - Recycling
KW - Circular Economy
PY - 2024
UR - https://leichtbausymposium.de/deu/
AN - OPUS4-60683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Luminescent multifunctional nanostructures for sensing and theranostics applications
N2 - The research carried out at the Laboratory of Spectroscopy of Functional Materials at IFSC/USP, in Brazil, is focused on the synthesis and structural-property correlation of luminescent materials including rare-earth (RE) doped glasses, ceramics and hybrid host-guest materials. For the past five years, we have been particularly interested in the development of single- and multifunctional nanosystems based on core-shell upconversion nanoparticles (UCNP) associated with dyes, organometallic complexes and other organic molecules, for biophotonic and sensing applications. In these systems, we take advantage of energy transfer between the UCNPs and the molecules to either supress or enhance luminescent response. Examples include the possibility of bioimaging and photodynamic therapy of bacteria and cancer cells, simultaneous magnetothermia and thermometry, localized O2 sensing, fast detection and quantification of biological markers (e.g. kidney disease) and microorganisms. On what concerns the development of luminescent sensors - a recently started project, our aim is to develop paper-based platforms for point-of-care devices. In this presentation, an overview of our contributions for the past years and our future aims will be presented with several examples.
T2 - ICL2023 - 20th International Conference on Luminescence
CY - Paris, France
DA - 27.08.2023
KW - Upconversion
KW - Sensing
KW - Theranostics
KW - Nanoparticles
KW - Photodynamic therapy
PY - 2023
AN - OPUS4-60362
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Elastic Microstructures in Metallic Glasses
N2 - Metallic glasses (MGs) are disordered solids that exhibit a range of outstanding mechanical, thermomechanical, and functional properties. Whilst being a promising class of structural materials, well-defined and exploitable structure-property relationships are still lacking. This offsets them strongly from the crystalline counterparts, for which length-scale based property determination has been key for decades.
In recent years, both atomistic simulations and experiments have nurtured the view of heterogeneities that manifest themselves either as a structural partitioning into well-relaxed percolated network components and more frustrated domains in atomistic simulations, or as spatially-resolved property fluctuations revealed with atomic force microscopy. These signatures depend sensitively on the processing history and likely reflect emerging medium-range order fluctuations at the scale of 1-10 nanometers.
Here we demonstrate and discuss the emergence of spatially resolved property fluctuations at length scales that are one to two orders of magnitude larger. Such long-range decorrelation length scales are hard to reconcile in a monolithic glass but may offer the perspective of experimentally easy-to-access length-scale based structure-property relationships. Whilst long-range property fluctuations can be seen in both the plastic and elastic response, we focus here on high-throughput elastic nanoindentation mapping across the surface of a Zr-based model glass. After a deconvolution of surface topography and curvature effects, the spatially-resolved elastic response reveals an elastic microstructure with a correlation length of ca. 150-170 nm. Analytical scanning-transmission electron microscopy (STEM) is used to link the elastic property fluctuations to the chemistry and structure of the MG. In concert, nano-elastic mapping and STEM suggests that structural variations in the glass are responsible for the unexpectedly large length scales. We discuss these findings in terms of the materials processing history and the perspective of exploiting nanoindentation-based spatial mapping to uncover structural length scales in atomically disordered solids.
T2 - 7th International Indentation Workshop – IIW7
CY - Hyderabad, India
DA - 17.12.2023
KW - Metallic glass
KW - Nanoindentation
KW - Microstructure
PY - 2023
AN - OPUS4-60692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
T1 - Der KorroPad Korrosions-Schnelltest Einfach, schnell, zerstörungsfrei
N2 - Eine kurze Einführung in den KorroPad test. Kombiniert mit einer praktischen Vorführung.
T2 - Tag der Technik, Romain-Rolland-Gymnasium
CY - Berlin, Germany
DA - 16.07.2024
KW - Korrosion
KW - Experimente
KW - KorroPad
PY - 2024
AN - OPUS4-60664
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
T1 - Embracing AI and User-Centered Design in Modern Technological Systems: The Case of Non-Destructive Testing
N2 - The use of artificial intelligence (AI) in the design of technological systems is now ubiquitous. Non-destructive testing (NDT)—a set of techniques used to evaluate the properties and integrity of materials, components, or structures without causing damage to the tested object—is one of the disciplines seeking to benefit from this technology to increase reliability, safety, and productivity. Human-machine interaction (HMI), a recognized key area within Industry 4.0, plays an important role in the design, development, acceptance, and successful implementation of these systems.
The integration of AI will significantly transform NDT tasks, introducing new tools, higher levels of process automation, and fully automated integration into production systems. The addition of assistive technologies like augmented reality will alleviate manual tasks but increase complexity, marking a transitional phase. For an NDT system to fully integrate into the broader Industry 4.0 framework, it must move beyond its traditional role as a self-contained entity and become part of a larger interconnected system. This transition will require new ways of interacting with technology, new task demands, and new competencies such as data analytics, automation, usability, control, oversight, communication, and complex problem-solving.
We propose a paradigm shift to new roles: the Systems Developer, responsible for strategizing, developing, and integrating NDT systems with input from multiple sources and automation systems; the Caretaker, monitoring system functionality, resolving errors, and managing day-to-day operations; and the Problem Solver, diagnosing system problems and ensuring proper functioning. This development involves a multidisciplinary team, known as the "UX Design" role, tasked with creating a physical system that mediates between users and information sources to enhance inspection reliability and user acceptance.
It is agreed that AI systems will continue to be operated and controlled by humans, so addressing human-machine interaction is paramount. The transition to more advanced NDT systems presents challenges such as adapting to complex technologies, addressing skill loss, and ensuring user acceptance. To overcome these hurdles, a user-centered approach that emphasizes intuitive interfaces and appropriate roles for humans and automation is critical. In addition, training programs tailored to new roles and responsibilities can help mitigate skill loss, while clear communication and phased implementation strategies are essential to manage organizational change and user resistance. By effectively addressing these challenges, companies can maximize the benefits of advanced AI technologies.
Non-destructive testing serves as an illustrative example, but the principles and strategies discussed apply broadly across various technological systems integrating AI and HMI. The evolution towards more advanced, AI-driven systems demands a careful balance between technological capabilities and human factors, ensuring that the full potential of these innovations can be realized in a practical, user-friendly manner.
T2 - 6th International Conference on Human Systems Engineering and Design: Future Trends and Applications (IHSED 2024)
CY - Split, Croatia
DA - 27.09.2024
KW - Human Factors
KW - Artificial intelligence
KW - AI
KW - Human-Machine Interaction
KW - Non-Destructive Testing
KW - Acceptance
PY - 2024
AN - OPUS4-61868
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
T1 - Ellipsometry as optical metrology method for analysis of reference materials for nanoelectronics
N2 - Electrical properties of materials at the nanoscale can be characterized using scanning microwave microscopes (SMM) and conductive atomic force microscopes (C AFM). However, the measurement results are difficult to compare since different setups and different reference standards are used. The development of new “out-of-lab” reference standards can contribute to the traceability and reliability of these scanning probe microscopy methods (SPM) and facilitate their broader industrial application.
In this study, we discuss the capability of optical methods such as ellipsometry for the characterization of existing and the development of new reference calibration samples for scanning microwave microscopy. Ellipsometry is a fast and non-destructive method, which enables very accurate determination of the layer thickness and the dielectric functions of the materials. Imaging ellipsometry is suitable for spatially resolved measurements when analyzing thin layers in microstructured samples.
We show how the electrical resistivity of indium tin oxide (ITO) layers in newly designed resistive calibration samples can be obtained from spectroscopic ellipsometric measurements. The extension of the measurement range into the mid-infrared region was necessary when analyzing ITO layers with low conductivity. This parameter was obtained by fitting a Drude function describing the absorption of the free carriers. The impact of the coating process conditions on the layer properties is discussed.
Imaging ellipsometry was applied for the characterisation of thin ITO and SiO2 layers in microstructured resistive and capacitance calibration kits. The uncertainties of determined layer thicknesses were specified according to standardized practice guides used in ellipsometry. We show how statistical fingerprint analysis of the measured ellipsometric transfer quantities can be used to validate the quality of potential reference materials for nano-electronics and to monitor the processing of structured samples.
T2 - L. ALTECH 2024 - Analytical techniques for accurate nanoscale characterization of advanced materials
CY - Strasbourg, France
DA - 27.05.2024
KW - Ellipsometry
KW - Reference materials
KW - Transparent conductive Oxides
KW - Scannig probe microscope
KW - Metrology
KW - Nanoelectronics
PY - 2024
AN - OPUS4-60268
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bulling, Jannis
A1 - Jurgelucks, B.
A1 - Prager, Jens
A1 - Walther, A.
T1 - Modellierung und Validierung eines inversen Verfahrens zur Schadensrekonstruktion mittels Lamb-Wellen im Ultraschallbereich
N2 - Das Ausbreitungsverhalten geführter Ultraschallwellen ermöglicht die großflächige Prüfung von Platten und schalenförmigen Bauteilen wie Rohren und Laminaten auf Fehlstellen von wenigen Prüfpunkten aus. Während die beschränkte Divergenz der geführten Wellen die Ultraschallprüfung begünstigt, erschwert das dispersive und multimodale Verhalten der Lamb-Wellen die Auswertung der Ultraschallsignale. Die dispersive und multimodale Wellenausbreitung verkompliziert die Bestimmung der Fehlerposition bei der Auswertung der Geschwindigkeiten einzelner Wellenpakete. Zudem ist es herausfordernd, einen einfachen Zusammenhang zwischen den Reflexionen der Fehlstelle und deren Größe und Form herzustellen. Eine Möglichkeit zur genauen Bestimmung der Fehlerposition und -geometrie bietet der direkte Vergleich der Messsignale mit den Signalen aus einem Simulationsmodell. Die Nachbildung des Schadens im Simulationsmodell stellt ein inverses Problem dar, das iterativ gelöst werden kann, indem ein Vorwärtsmodell immer weiter optimiert wird. Klassische Ansätze wie die Finite Elemente Methode (FEM) sind für die Simulation von Ultraschallwellen aufgrund der kleinen Wellenlängen im Vergleich zur Bauteilgröße meist ineffizient. Aus diesem Grund basiert das vorgestellte Vorwärtsmodell auf der semi-analytischen Scaled Boundary Finite Element Method (SBFEM), die große Teile der Wellenausbreitung analytisch berechnet. In diesem Beitrag wird die Validierung des zweidimensionalen Modells an Platten mit einer rechteckigen Nut als Ersatzfehler präsentiert und es werden erste Schritte zur Validierung von 3D-Modellen vorgestellt.
T2 - DAGA 2024
CY - Hannover, Germany
DA - 18.03.2024
KW - Geführter Ultraschall
KW - Inverse Verfahren
KW - SBFEM
PY - 2024
AN - OPUS4-60214
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Determining Material Properties with Spectroscopic Ellipsometry
N2 - In this lecture, an introduction will be given on Spectroscopic Ellipsometry, what quantities can be obtained with it, and how we use it in ELENA and other projects to determine functional parameters of thin layers at the nanoscale.
T2 - Summer school ELENAM : metrology at the nanoscale
CY - Fréjus, France
DA - 02.06.2024
KW - Thin Layers
KW - Ellipsometry
KW - Nanotechnology
KW - Electrical Paramters
PY - 2024
AN - OPUS4-60247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Würth, Christian
T1 - Time resolved spectroscopy of upconverting lanthanide based upconversion nanocrystals
N2 - This presentation gives an overview of time correlated population and depopulation processes of the electronic states of lanthanide doped nanoparticles. The fundamental principles of sensitized photon upconversion are explained. Theoretical principles and the correlation to experimental results are shown. Examples are given for particle growth, dissolution as well as influences of size, doping concentration and microenvironment.
T2 - Principles and Applications of Time-resolved Fluorescence Spectroscopy
CY - Berlin, Germany
DA - 12.11.2024
KW - Upconversion
KW - Time domain
PY - 2024
AN - OPUS4-61652
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Neues von der Bundesanstalt für Materialforschung und –prüfung
N2 - Es werden ausgewählte Folien aus der Standard-BAM-Präsentation gezeigt, im Anschluss daran die besonderen Kompetenzen des Fachbereichs 7.6. Dort wird insbesondere auf Anknüpfungspunkte zu Infrastruktur (Leitungen, Brücken,…) abgestellt.
T2 - Sitzung DVGW-Landesgruppe Berlin-Brandenburg
CY - Potsdam, Germany
DA - 21.04.2024
KW - Kompetenzen
KW - BAM
KW - Korrosion
PY - 2024
AN - OPUS4-61841
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - On the use of spectroscopic imaging ellipsometry for quantification and characterisation of defects in thin films for power electronics
N2 - Compound semiconductors (CS) are promising materials for the development of high-power electrical applications. They have low losses, can withstand high temperatures and can operate at very high voltages and currents. This makes them a key technology for the electrification of many high energy applications, especially electromobility and HVDC power lines.
The challenge with CS technology is that most of the process technology has to be developed anew to the high standards required by electronic applications. Today, compound semiconductors can be produced in thin layers on top of substrates fabricated from classical crystal growth processes that are already well established. A promising method for this is metal organic vapour phase epitaxy (MOVPE). With this method, many different compounds with semiconducting properties can be synthesized. Additionally, this process technology is a direct thin layer deposition method. Therefore, complex multilayer systems can be generated directly by the deposition process and without the need of doping after growing.
There are a number of critical defects that can originate from the deposition process of these thin film devices. Within this project, we intend to develop new correlative imaging and analysis techniques to determine defect types, to quantify defect size and number density, as well as to characterise defects for process optimisation.
We report here on the use of spectroscopic ellipsometry and imaging ellipsometry to investigate defects in several different compound semiconductor materials used in high-power electronic devices. The materials we investigated are β-Ga2O3, SiC, GaN, AlN, and AlGaN materials as well as oxidised SiC surfaces. All of these materials have their typical defects and require optimised measurement and analysis schemes for reliable detection and analysis. Spectroscopic ellipsometry is a highly sensitive method for determining the thicknesses and dielectric function of thin layers, yielding potentially a high number of microscopic properties. The combined method between ellipsometry and optical microscopy is called imaging ellipsometry and is especially powerful for the large amount of data it produces. We have analysed defects in SiC- and AlN-based thin film semiconductors as well as characterised the properties of different types of SiO2 layers created on top of SiC monocrystals. We developed ellipsometric models for the data analysis of the different semiconductor materials.
If the defects have geometric features, it is useful to combine the ellipsometric analysis with topometry method like interference microscopy and scanning probe microscopy. We have successfully characterised function-critical defects in MOVPE SiC layers and correlated the findings with topography from WLIM measurements. We have developed an imaging ellipsometric measurement methodology that allows to estimate the relative defect area on a surface by a statistical raw data analysis.
Compound semiconductors (CS) are promising materials for the development of high-power electrical applications. They have low losses, can withstand high temperatures and can operate at very high voltages and currents. This makes them a key technology for the electrification of many high energy applications, especially electromobility and HVDC power lines.
The challenge is that most of the process technology has to be developed specifically and tailored to the high standards required by electronic applications. Today, many different CS materials can be produced in thin layers on top of substrates fabricated from classical crystal growth processes that are already well established. A promising method for this is metal organic vapour phase epitaxy (MOVPE). This technology is a direct thin layer deposition method capable of producing complex multilayer systems directly from one deposition process without the need of doping after growing.
There are a number of critical defects that can originate from the deposition process when targeting electronic thin film devices. Within this project, we intend to develop new correlative imaging and analysis techniques to determine defect types, to quantify defect size and density, as well as to characterise defects for further process optimisation.
We report here on the use of spectroscopic and multispectral imaging ellipsometry to investigate defects in several different compound semiconductor materials used in high-power electronic devices. The materials we investigated are β-Ga2O3, SiC, GaN, AlN, and AlGaN as well as oxidised SiC. All of these materials have their typical defects and require optimised measurement and analysis schemes for reliable detection and analysis. Spectroscopic ellipsometry is a highly sensitive method for determining the thicknesses and dielectric function of thin layers, yielding potentially a high number of microscopic properties. The combined method between ellipsometry and optical microscopy is known as imaging ellipsometry and is especially powerful for the large amount of data it produces. We have analysed defects in SiC- and AlN-based thin film semiconductors as well as characterised the properties of different types of SiO2 layers created on top of SiC monocrystals. We developed ellipsometric models for the data analysis of the different semiconductor materials.
If the defects have geometric features, it is useful to combine the ellipsometric analysis with topometry methods like interference microscopy and scanning probe microscopy. We have successfully characterised function-critical defects in MOVPE SiC layers and correlated the findings with topography from WLIM measurements. We have developed an imaging ellipsometric measurement methodology that allows to estimate the relative defect area on a surface by a statistical raw data analysis.
T2 - EMRS Spring Meeting 2024 - ALTECH 2024
CY - Strasbourg, France
DA - 27.05.2024
KW - Ellipsometry
KW - Power Electronics
KW - Layer Materials
KW - Defect Analysis
PY - 2024
AN - OPUS4-60266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kozdras, Mark
T1 - Towards a Self-driving Lab for Nanoparticle Research
N2 - Society is currently confronted with two global challenges, climate change and sustainable development. This reality reverberates amongst the leading nations of the world and is articulated as a priority by the United Nations through the Framework Convention on Climate Change and its seventeen Sustainable Development Goals. In 2016, under the Paris Accord, Mission Innovation, MI, emerged as a global response to climate change and developed eight innovation challenges to mitigate its effect, including Clean Energy Materials, IC6. This innovation challenge focused its efforts on accelerating the development and deployment of clean energy materials by more than a factor of ten through Materials Acceleration Platforms, MAPs – autonomous, self-driving materials laboratories and renewed itself under the current mandate as Materials for Energy, M4E.
Self-driving labs deploy artificial intelligence, robotic automation and high-performance simulation and modeling in a closed loop system of material synthesis and characterization. An international ecosystem for accelerated materials discovery has been established and finds applications in many enabling materials technologies, including nanomaterials. The importance of nanomaterials to catalysis for hydrogen production and carbon dioxide conversion as well as energy storage in batteries is well known. In this work, the international efforts under Materials for Energy will be elaborated including the development of MINERVA - MAP for Intelligent Nanomaterial synthesis Enabled by Robotics for Versatile Applications. MINERVA was specifically built to include the specialized equipment required for the synthesis, characterization and closed-loop optimization of various nano- and advanced materials, ranging from simple inorganic (silica, metal, metal oxide) or polymeric nanoparticles to more complex core-shell architectures and materials with well-defined porosity or surface chemistry. Currently, we are investigating materials for applications in antimicrobial and antibiofouling surface coatings, sensor materials, as well as the reproducible synthesis of reference materials with this platform.
T2 - Nanotek 2024
CY - Barcelona, Spain
DA - 25.03.2024
KW - Self-driving Labs
KW - SDLs
KW - Advanced Materials
KW - Autonomous Materials Discovery
KW - Nanoparticles Synthesis and Characterization
PY - 2024
AN - OPUS4-60382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunji Purayil, Sruthi Krishna
A1 - Balasubramaniam, K.
T1 - Data-driven AI for the automated classification of the isothermal heat-treated thermal barrier coatings using pulsed infrared thermography
N2 - Development of reliable age prediction models are crucial in monitoring the formation of oxide layer and degradation of TBC at regular intervals. This study proposes an automated classification of isothermal heat-treated TBC samples using temperature data, which helps in predicting the TBC life and monitoring the TBC degradation. TBC-coated samples are isothermal heat-treated at 1000 °C, and the initial growth of thermally grown oxide is monitored using a non-destructive thermal imaging technique. The proposed study integrates data-driven AI (DAI) models and feature extraction techniques to interpret complex thermal patterns measured from the TBC coating surface. The performance of the proposed classification framework is tested using deep learning and classical machine learning models with different types and window sizes of input data. Input data used for validation are raw experiment data, logarithmic of experiment data, polynomial fit data, and thermal signal reconstruction fit coefficients. The maximum c
KW - Infrared thermography
KW - NDT
KW - Artificial intelligence
KW - Deep learning
KW - Predictive maintenance
PY - 2024
DO - https://doi.org/10.1088/1361-6463/ad8ce7
SN - 1361-6463
VL - 58
IS - 4
SP - 1
EP - 10
PB - IOP Publishing
CY - Bristol
AN - OPUS4-61641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Petrushina, M.
A1 - Dedova, E.
A1 - Portnaygin, A.
A1 - Papynov, E.
A1 - Filatov, E.
A1 - Korenev, S.
A1 - Gubanov, A.
T1 - Effect of temperature and pressure on mixed oxide solid solutions
N2 - A hydrothermal synthesis of ZrW2-xMoxO8 (0 ≤ x ≤ 2) from the corresponding precursors is reported in this paper. High-temperature and high-pressure data are presented for the sample with x = 1.6. An increase in temperature initiates the phase transition from tetragonal precursor to orthorhombic-ZrW2-xMoxO8 (x = 1.6) with the subsequent formation of cubic and trigonal phases. The thermolysis parameter of the disordered cubic ZrW2-xMoxO8 (x = 1.6) phase is 803 K, and the coefficient of thermal expansion is α = -4.6∙10–6 K−1. Data on ZrW2-xMoxO8 (x = 1.6) structure as a function of pressure are obtained for the first time. Pressureinduced changes from cubic to orthorhombic ZrW2-xMoxO8 (x = 1.6) phase at 1.38 GPa are observed. The sample amorphization is irreversible during decompression.
KW - Phase transition
KW - High-pressure
KW - Complex oxides
PY - 2020
DO - https://doi.org/10.1016/j.inoche.2020.107965
VL - 117
SP - 107965
PB - Elsevier B.V.
AN - OPUS4-50821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Besselink, R.
A1 - Chatzipanagis, K.
A1 - Hövelmann, J.
A1 - Benning, L. G.
A1 - Van Driessche, E. S.
T1 - Nucleation Pathway of Calcium Sulfate Hemihydrate (Bassanite) from Solution: Implications for Calcium Sulfates on Mars
N2 - CaSO4 minerals (i.e., gypsum, anhydrite, and bassanite) are widespread in natural and industrial environments. During the last several years, a number of studies have revealed that nucleation in the CaSO4–H2O system is nonclassical, where the formation of crystalline phases involves several steps. Based on these recent insights, we have formulated a tentative general model for calcium sulfate precipitation from solution. This model involves primary species that are formed through the assembly of multiple Ca2+ and SO42– ions into nanoclusters. These nanoclusters assemble into poorly ordered (i.e., amorphous) hydrated aggregates, which in turn undergo ordering into coherent crystalline units. The thermodynamic (meta)stability of any of the three CaSO4 phases is regulated by temperature, pressure, and ionic strength, with gypsum being the stable form at low temperatures and low-to-medium ionic strengths and anhydrite being the stable phase at high temperatures and at lower temperature for high salinities. Bassanite is metastable across the entire phase diagram but readily forms as the primary phase at high ionic strengths across a wide range of temperatures and can persist up to several months. Although the physicochemical conditions leading to bassanite formation in aqueous systems are relatively well established, nanoscale insights into the nucleation mechanisms and pathways are still lacking. To fill this gap and to further improve our general model for calcium sulfate precipitation, we conducted in situ scattering measurements at small-angle X-ray scattering and wide-angle X-ray scattering and complemented these with in situ Raman spectroscopic characterization. Based on these experiments, we show that the process of formation of bassanite from aqueous solutions is very similar to the formation of gypsum: it involves the aggregation of small primary species into larger disordered aggregates, only from which the crystalline phase develops. These data thus confirm our general model of CaSO4 nucleation and provide clues to explain the abundant occurrence of bassanite on the surface of Mars (and not on the surface of Earth).
KW - Gypsum' SAXS
KW - Calcium sulfate
KW - Bassanite
KW - Nucleation
PY - 2020
DO - https://doi.org/10.1021/acs.jpcc.0c01041
VL - 124
IS - 15
SP - 8411
EP - 8422
PB - American Chemical Society
AN - OPUS4-50849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Thieme, C.
A1 - Rüssel, C.
T1 - Crystal growth velocities of a highly anisotropic phase obtained via surface and volume crystallization of barium–strontium–zinc silicate glasses
N2 - In the past few years, a new phase, Ba0.5Sr0.5Zn2Si2O7 with negative thermal expansion has been described in the literature. Some excess of SiO2 is necessary to produce glasses from which the Ba0.5Sr0.5Zn2Si2O7 phase can be crystallized.
Unfortunately, in such glasses usually surface crystallization occurs; however, the addition of nucleating agents such as trace quantities of platinum or relatively high quantities of ZrO2 is necessary to achieve bulk nucleation. These additional components also affect the crystal growth velocity, which furthermore is different for crystal growth from the surface and in the bulk. In this paper, three different chemical compositions containing different ZrO2 concentrations, where one composition additionally contains 100 ppm platinum, are studied with respect to their crystallization behaviour. Although the compositions do not differ much, the crystallization behaviour and also the Crystal growth velocities are surprisingly different.
KW - Glass ceramic
KW - Crystal growth velocity
KW - Low expansion
PY - 2020
DO - https://doi.org/10.1007/s10853-020-04773-6
SN - 0022-2461
VL - 55
SP - 10364
EP - 10374
PB - Springer
AN - OPUS4-50853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - GISAXS and XRR for STOP - M30 update
N2 - With a representative set of samples measured in reflection geometry at the MOUSE we lead through our recent advances in this talk. A thin polystyrene film serves as an example for X-ray reflectivity and we show the effect of polishing on the reflectivity of stainless steel. Polystyrene spheres spin-coated onto different substrates including the polished stainless steel are demonstrated to show the characteristic scattering of spherical particles in GISAXS. We conclude with the first GISAXS data from laser-induced periodic surface structures (LIPSS) recorded at the MOUSE.
T2 - M30 project meeting Surface Transfer of Pathogens (STOP)
CY - Sofia, Bulgaria
DA - 27.02.2025
KW - X-ray reflectivity
KW - Substrate roughness
KW - Grazing incidence
KW - Particle-based coating
PY - 2025
AN - OPUS4-62777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigel, Sandra
A1 - Sielaff, S.
A1 - Kunsic-Nowak, T.
A1 - Nytus, N.
A1 - Schwettmann, K.
A1 - Schulze, C.
A1 - Wetekam, J.
T1 - Die FTIR-Untersuchung von Bitumen: Chancen, Durchführung und Präzision
N2 - Die Fourier-Transformations-Infrarot-Spektroskopie (FTIR-Spektroskopie) stellt eine innovative und wirkungsvolle Methode zur Charakterisierung von Bitumen und bitumenhaltigen Bindemitteln dar. So erlaubt die FTIRCharakterisierung nicht nur eine Bewertung des Alterungsfortschritts eines Bindemittels, sondern zudem auch die Identifizierung von im Bitumen enthaltenen Additiven und Schadstoffen wie z. B. polyzyklischen aromatischen Kohlenwasserstoffen (PAK), die Ableitung verschiedener physikalischer und chemischer Kennwerte sowie weiterhin eine Klassifizierung von Bindemitteln nach verschiedenen übergeordneten Eigenschaften wie der Raffinerie, dem Alterungszustand und auch der Alterungsempfindlichkeit.
KW - Bitumen und bitumenhaltige Bindemittel
KW - FTIR-Spektroskopie
KW - Anwendungsmöglichkeiten
KW - Vergleichuntersuchung
KW - Arbeitsanleitung
KW - Präzision
PY - 2023
UR - https://www.kirschbaum.de/fachzeitschriften/strasse-und-autobahn/strasse-und-autobahn/aktuelles-heft-17.html
DO - https://doi.org/10.53184/STA8-2023-4
VL - 74/8
SP - 630
EP - 642
PB - KIRSCHBAUM VERLAG GmbH
CY - Bonn
AN - OPUS4-59049
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Besselink, R.
A1 - Stawski, Tomasz
A1 - Freeman, H. M.
A1 - Hovelmann, J.
A1 - Tobler, D. J.
A1 - Benning, L. G.
T1 - Mechanism of Saponite Crystallization from a Rapidly Formed Amorphous Intermediate
N2 - Clays are crucial mineral phases in Earth’s weathering engine, but we do not know how they form in surface environments under (near-)ambient pressures and temperatures. Most synthesis routes, attempting to give insights into the plausible mechanisms, rely on hydrothermal conditions, yet many geological studies showed that clays may actually form at moderate temperatures (<100 °C) in most terrestrial settings. Here, we combined high-energy X-ray diffraction, infrared spectroscopy, and transmission electron microscopy to derive the mechanistic pathways of the low-temperature (25–95 °C) crystallization of a synthetic Mg-clay, saponite. Our results reveal that saponite crystallizes via a two stage process: (1) a rapid (several minutes) coprecipitation where ∼20% of the available magnesium becomes incorporated into an aluminosilicate network, followed by (2) a much slower crystallization mechanism (several hours to days) where the remaining magnesium becomes gradually incorporated into the growing saponite sheet structure.
KW - Saponite
KW - FTIR
KW - PDF
KW - Diffraction
PY - 2020
DO - https://doi.org/10.1021/acs.cgd.0c00151
VL - 20
IS - 5
SP - 3365
EP - 3373
PB - American Chemical Society
AN - OPUS4-50917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Hensel, Jonas
T1 - Application of fracture mechanics to weld fatigue
N2 - The application of fracture mechanics to the determination of the fatigue behavior of weldments is discussed with the focus on classic fatigue, i.e., the overall fatigue life and the fatigue strength in terms of an S-N curve and the endurance limit. The following issues are addressed: specific features of short fatigue crack propagation, an adequate initial crack size, multiple crack propagation and its statistical treatment as well as welding residual stresses. As an example, an approach of the authors is applied to the determination of FAT classes for a butt weld with varying weld toe geometry.
KW - Weld fatigue
KW - Weld toe geometry
KW - Short crack propagation
KW - FAT class concept
PY - 2020
DO - https://doi.org/10.1016/j.ijfatigue.2020.105801
SN - 0142-1123
VL - 139
SP - 105801
PB - Elsevier Ltd.
AN - OPUS4-50991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Oliveira, C.
A1 - Silveira, D.
A1 - Varum, H.
A1 - Parisi, F.
A1 - Miccoli, Lorenzo
A1 - Solis, M.
A1 - Rodriguez-Mariscal, J. D.
A1 - Tarque, N.
ED - Varum, H.
ED - Parisi, F.
ED - Tarque, N.
ED - Silveira, D.
T1 - Mechanical Characterization of Adobe Masonry
N2 - The characterization of the mechanical properties and behaviour of adobe masonry is fundamental for the understanding of the structural behaviour of adobe constructions. Thus, in the last decades, experimental studies focused on this topic have been carried out by different authors. Many of the existing experimental works, however, were carried out aiming to support broader studies focused on the seismic behaviour of adobe constructions and are not very detailed. Moreover, authors tend to adopt different procedures in their experimental work, since there are few indications in existing standards for testing adobe masonry. The wide variety in materials used, both for the adobes and mortars, further complicates this work, making it difficult to compare results obtained in different studies. This chapter provides an overview of the indications given by standards and other technical recommendations for the mechanical testing of adobe masonry. It presents a review of existing research on the mechanical behaviour of adobe masonry, addressing studies that focus on: (i) compression behaviour, (ii) shear behaviour, (iii) joint shear behaviour. It provides a global analysis of the existing knowledge, suggesting improvements for normative documents and identifying future Research needs.
KW - Adobe masonry
KW - Mechanical behaviour
KW - Experimental tests
KW - Standards
PY - 2021
SN - 978-3-030-74736-7
DO - https://doi.org/10.1007/978-3-030-74737-4_4
SN - 2194-9832
VL - 20
SP - 55
EP - 92
PB - Springer Nature Switzerland AG
AN - OPUS4-54171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Silveira, D.
A1 - Oliveira, C.
A1 - Varum, H.
A1 - Ioannou, I.
A1 - Miccoli, Lorenzo
A1 - Tarque, N.
A1 - Parisi, F.
A1 - Fenu, L.
A1 - Solis, M.
A1 - Rodriguez-Mariscal, J. D.
ED - Varum, H.
ED - Parisi, F.
ED - Tarque, N.
ED - Silveira, D.
T1 - Mechanical Characterization of Adobe Bricks
N2 - The mechanical characterization of adobe bricks is an important first step in the study of the behaviour of adobe masonry. For this reason, in the last decades, different authors have conducted research on the mechanical behaviour of adobes from various regions of the world. Despite the importance of mechanical characterization, there are still only a few standards and normative documents with clear indications for the mechanical testing of earthen materials and, in general, These indications are not thorough and vary among different countries. Consequently, authors tend to adopt different types of test specimens and procedures in their experimental work, thus obtaining results that are not directly comparable. The fact that the materials and procedures traditionally used are also not standardized,varying greatly from region to region, also contributes to the difficulty of comparing results from different studies. This chapter presents a review of the indications provided by codes, standards and other technical recommendations for the mechanical testing of adobe bricks, as well as a detailed review of procedures adopted, and results obtained by different authors regarding the mechanical characterization of traditional adobe bricks. This chapter focuses, in particular, on the behaviour of adobe bricks when subjected to simple compression. It provides an overview of the existing knowledge and identifies needs for future research and development.
KW - Adobe
KW - Adobe masonry
KW - Mechanical behaviour
KW - Test procedures
KW - Standards
PY - 2021
SN - 978-3-030-74736-7
DO - https://doi.org/10.1007/978-3-030-74737-4
SN - 2194-9832
VL - 20
SP - 35
EP - 54
PB - Springer Nature Switzerland AG
AN - OPUS4-54170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
T1 - Modeling the Relationship between Weld Pool Dynamics and Centerline Solidification Cracking in High Power Laser Beam Welding
N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and two thermal imaging cameras is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs above 10 mm penetration depth. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.
T2 - Gastvortrag an der Universität Innsbruck, Institut für Konstruktion und Materialwissenschaften
CY - Innsbruck, Austria
DA - 18.06.2023
KW - Laser beam welding
KW - Centerline solidification cracking
KW - Bulging
KW - Numerical simulation
PY - 2024
AN - OPUS4-60333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krütt, Enno
A1 - Weise, Frank
A1 - Meng, Birgit
T1 - Einfluss einer druckschwellinduzierten Degradation von Fahrbahndeckenbeton auf die schädigende AKR
T1 - Influence of cyclic compressive loading induced degradation
of road pavement concrete on harmful AAR
N2 - In den letzten Jahren sind im deutschen Bundesautobahnnetz verstärkt Schäden an vor 2005 errichteten Betonfahrbahndecken aufgetreten, die mit einer Alkali-Kieselsäure-Reaktion (AKR) in Verbindung gebracht werden. Neben dem AKR-fördernden Einfluss von alkalihaltigen Taumitteln werden Fahrbahndecken zyklischen mechanischen Belastungen infolge des Verkehrs und Zwangsspannungen durch klimatische Einwirkungen ausgesetzt. Solche mechanischen Belastungen werden bisher in keinem AKR-Prüfverfahren berücksichtigt. Die zyklischen Belastungen können zu einer Degradation des Betongefüges führen, die ggf. einen AKR-fördernden Einfluss hat. Dieser Beitrag stellt Untersuchungen vor, die zur Beantwortung der Frage nach dem Einfluss einer zyklischen mechanischen Belastung auf den AKR-Schadensprozess beitragen. Dabei wird der Hypothese nachgegangen, dass die ermüdungsinduzierte Degradation zu einer Erhöhung des Stofftransports führt.
Dieser hat einen Einfluss auf die AKR-Schadensentwicklung, da die Reaktionspartner zunächst zum Reaktionsort transportiert werden müssen. Daher wird angenommen, dass sich mit dem Stofftransport auch die AKR-Schädigung verstärkt. Es werden Betonproben aus typischen Fahrbahndeckenbetonen einer vorgeschalteten zyklischen Druckschwellbelastung ausgesetzt.
Die Degradation infolge der Vorbelastung wird simultan mittels ZfP-Verfahren charakterisiert. Anschließend werden die Auswirkungen der zyklischen Vorschädigung auf den Stofftransport sowie auf die AKR vergleichend an Prüfkörpern ohne und mit Vorschädigung untersucht. Die Ergebnisse lassen den Schluss zu, dass die zyklische Vorschädigung sowohl den Stofftransport als auch die AKR fördert.
N2 - In recent years the German motorway network has seen an increase in the occurrence of damage to concrete road surfaces built before 2005, which can be attributed to the alkali-silica reaction (ASR). In addition to exposure to ASR-stimulating alkalirich deicing-agents, road surfaces are also subjected to cyclical mechanical loading resulting from traffic and induced stresses due to climatic impact. Such mechanical loadings are not considered in any of the previously developed ASR testing procedures. This cyclical loading could, however, lead to a degradation of the concrete microstructure and, in turn, stimulate the ASR-process. This article presents investigations that contribute to answering the question of whether a mechanically induced degradation influences the ASR-process. The hypothesis that the mechanically induced degradation leads to an increase in mass transport is examined. The mass transport is important for the ASR process because the reactants need to be transported to the reaction location before the reaction can take place. Therefore, it is assumed that increased mass Transport also leads to increased ASR damage. Concrete specimens made of typical pavement concretes are subjected to a predamaging cyclic compressive loading. The degradation is characterized simultaneously during the pre-damaging process using non-destructive testing (NDT) techniques. Then the effects of the cyclical pre-damage on the mass transport as well as on the ASR are determined by comparing results from test specimens with and without pre-damage. The results lead to the conclusion that the cyclical pre-damage increases both the mass transport and the ASR.
KW - Stofftransport
KW - Betonfahrbahndecken
KW - AKR
KW - Zyklische Belastung
KW - Degradation
PY - 2020
DO - https://doi.org/10.1002/best.202000017
SN - 0005-9900
VL - 115
IS - 10
SP - 779
EP - 788
PB - Wilhelm Ernst & Sohn
CY - Berlin
AN - OPUS4-51561
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fladt, Matthias
T1 - Internal water-repellent treatment – a novel strategy for mitigating alkali-aggregate reaction in concrete pavements
N2 - To prevent future alkali-aggregate reaction (AAR) damage, which has occurred frequently in the German highway network in recent years, a new regulation has been drafted. This regulation severely limits the use of alkali-sensitive aggregates by requiring that their suitability be verified by certified inspectors using newly developed AAR concrete tests that involve the external supply of alkali. This has led to a significant limitation in the number of aggregates usable for concrete pavements. A novel AAR avoidance strategy is now being pursued, which aims to enable the use of borderline alkali-sensitive aggregates through the application of an internal water-repellent treatment. The addition of water repellents during concrete production should significantly reduce the ingress of water and external de-icing salts into the concrete pavement, thus reducing the potential for AAR damage.
This paper presents the results of laboratory tests to assess the suitability of this new AAR prevention strategy. Representative, highly AAR-susceptible road paving concrete made with an alkali-sensitive greywacke and various water repellents were used as the basis for these experiments. The tests for concrete suitability included determining the conventional fresh and hardened concrete properties as well as concrete prism tests with external alkaline supply. Building on these results, laser-induced breakdown spectroscopy (LIBS) analyses of de-icing-salt intrusion as well as microscopic examinations for verification of the AAR characteristics were carried out.
The results of the AAR concrete tests with external alkaline supply support the conclusion that, when hydrophobic agents containing a suitable active ingredient are used, the AAR damage process in road paving concrete can be sufficiently prevented.
T2 - 16th International Conference on Alkali-Aggregate Reaction in Concrete
CY - Lisboa, Portugal
DA - 31.05.2022
KW - Concrete pavements
KW - Internal water-repellent treatment
KW - Preventive measures
KW - Testing for potential AAR
PY - 2022
AN - OPUS4-56870
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Weise, Frank
A1 - Hüsken, Götz
T1 - Ringversuch zum statischen Spaltzugversuch nach AL Sp-Beton
N2 - Für die rechnerische Dimensionierung der Betondecken im Oberbau von Verkehrsflächen für den Neubau sowie die Erneuerung nach RDO-Beton 09 ist die statische Spaltzugfestigkeit an der unteren und oberen Bohrkernscheibe entsprechend der Vorgaben der AL Sp-Beton zu bestimmen. Aufgrund der unzureichenden Kenntnis der Präzision dieses Prüfverfahrens wurden, basierend auf dem Entwurf des FGSV-Merkblatts zur statistischen Auswertung von Prüfergebnissen, mit einem breit aufgestellten Ringversuch die statistischen Kennwerte an Labor- und Bestandsbetonen unter Vergleich- und Wiederholbedingungen ermittelt. Zur möglichst guten statistischen Absicherung nahmen an dem Ringversuch dreizehn erfahrene Prüfstellen teil, die vorab einem Audit unterzogen wurden. Zur Abdeckung des vielschichtigen Einsatzes des Prüfverfahrens erfolgte der Ringversuch an acht Prüflosen, die sowohl die Erst-/ Eignungsprüfung und Übereinstimmungskontrolle bei Neubaumaßnahmen, als auch die Restsubstanzbewertung von Betonfahrbahnplatten berücksichtigen. Zur Bewertung des Materialeinflusses wurde zusätzlich ein Prüflos mit Labormörtel untersucht.
Die Probenvorbereitung erfolgte zentral an der BAM. Zur Sicherstellung einheitlicher Prüfbedingungen bei den Prüfstellen wurde zusätzlich eine detaillierte Standardarbeitsanweisung erarbeitet, die partiell bereits Eingang in das Normenwerk gefunden hat. Bei der Plausibilitätsprüfung aller prüflosspezifischen Einzelwerte der Spaltzug- und Druckfestigkeit wurden vereinzelt sowohl Ausführungsfehler als auch Übertragungs- und Tippfehler festgestellt. Der sich anschließende Lilliefors-Test zeigt, dass die ermittelten Einzelwerte bis auf wenige Aus-nahmen normalverteilt sind und damit die Voraussetzungen für die statistische Auswertung gegeben sind.
Mittels grafischer Darstellung der Mandel’s h- und k-Werte wurden die Auffälligkeiten hinsichtlich der Mittelwerte und Varianzen prüflosspezifisch für die einzelnen Prüfstellen visualisiert und anschließend einige von ihnen mittels Grubbs- und Cochran-Test als Ausreißer identifiziert. Nach Ausreißerelimination wurde mit dem klassischen Verfahren bei der Spaltzugfestigkeit der geringste Variationskoeffizient unter Vergleich- und Wiederholbedingungen bei der Erst-/Eignungsprüfung mit 6,2 und 6,4 Prozent ermittelt. Bei einer Verminderung des Materialeinflusses durch die Verwendung eines Labormörtels verbessern sich die statistischen Kennwerte auf 4,5 und 5,3 Prozent. Mit 8,2 und 9,5 Prozent beziehungsweise 8,6 und 9,5 Prozent werden bei der Restsubstanzbewertung von Wasch- und Unterbetonen die höchsten Werte bestimmt.
Das robuste Auswerteverfahren (ohne Eliminierung der Ausreißer) nach dem Entwurf des FGSV-Merkblatts zur statistischen Auswertung von Prüfergebnissen erwies sich in der Form als ungeeignet und bedurfte einer Überarbeitung. Bezüglich der vergleichend mit klassischen und robusten Verfahren gewonnenen Kennwerte ist festzustellen, dass bei sehr homogenen Messergebnissen eines Prüfloses beide Verfahren nahezu die gleichen statistischen Kennwerte liefern. Bei der Eliminierung von Ausreißern sind die Ergebnisse des robusten Verfahrens in der Regel etwas größer als die des klassischen Verfahrens.
Die begleitenden vertiefenden Untersuchungen bei der Spaltzugprüfung mit innovativen Prüftechniken lieferten wertvolle Erkenntnisse zur Bewertung der Prüfeinflüsse.
N2 - The computational design of concrete pavements according to the requirements of the RDO-Beton 09 requires the splitting tensile strength to be determined according to specifications of the AL Sp-Beton. However, detailed information on the precision of the described test procedure is missing. Therefore, a round robin test was set up in order to determine the statistical parameters of the prescribed splitting tensile strength test on laboratory concrete and cores extracted from concrete pavements in terms of repeatability and reproducibility. 13 testing institutes have been involved in the round robin test to guarantee a representative coverage of the sector. The selected testing institutes have been audited prior the round robin test in order to ensure their capabilities. The round robin test was divided into 8 testing lots for covering the broad field of possible applications. Thereby, the testing lots cover both the initial testing of concrete and quality control of new construction. The latter case implies also the assessment of existing concrete pavements. Additionally, a cementitious mortar was designed in order to consider the influence of the material, such as maximum grain size, on the test procedure.
The samples were prepared at BAM to guarantee a uniform sample preparation. Furthermore, a standard operating procedure was prepared to assure constant test conditions at the testing institutes. This standard operating procedure is already partly considered by the corresponding standard. A revision of the data reported by the testing institutes revealed that execution errors, transcription errors as well as typing errors occurred. However, a Lilliefors-Test was conducted to verify the Gaussian distribution of the reported test data and to allow the further statistical analysis. Only view data sets do not follow a Gaussian distribution, has no remarkable influence on the obtained statistical data.
By means of the graphical illustration of Mandel’s h- and k-values, abnormalities of the arithmetic mean and variance are depicted. These apparent abnormalities can be identified as outliers using the Grubbs and Cochran test. After eliminating the identified outliers, the corresponding statistical parameters have been determined using the classical method for data analysis. The lowest coefficient of variation that was determined for the splitting tensile strength by using the classical method for assessment of the repeatability and reproducibility of the test procedure amounts to 6.2 and 6.4%, respectively, for the initial testing of concrete. Reducing the material influence by using a cementitious mortar, the corresponding statistical parameters were reduced to 4.5 and 5.3%. On the contrary, the highest statistical values were obtained for the assessment of existing concrete pavements. Here, values of 8.2 and 9.5% were obtained for the exposed aggregate concrete and 8.6 and 9.5% for the subconcrete, respectively.
The robust method for data analysis (without elimination of outliers) according to the draft version of the technical bulletin of the FGSV turned out to be inappropriate and required, therefore, a revision. Comparing the statistical parameters obtained by the classical and robust method used for data analysis it can be stated that both methods result in nearly identical values for homogeneous data sets without outliers. Considering outliers in the existing data sets, the statistical parameters obtained by the robust method are slightly higher than the values obtained by the classical method with elimination of outliers.
The additional investigations on the splitting tensile strength using innovative test procedures provided valuable findings for the assessment of test results.
KW - Verfahrenspräzision
KW - Betonfahrbahndecke
KW - Prüfverfahren AL Sp-Beton
KW - Spaltzugfestigkeit
KW - Ringversuch
PY - 2022
SN - 978-3-95606-688-7
SN - 0943-9323
VL - Straßenbau Heft S 178
SP - 1
EP - 90
PB - Fachverlag NW in der Carl Ed. Schünemann KG
CY - Bremen
AN - OPUS4-54957
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kühnel, Alena
T1 - 3D-Ansprache von Betonfahrbahndeckentexturen
N2 - Die Oberflächentexturierung der Betonfahrbahndecken mittels Grinding und Grooving steht seit einigen Jahren im Mittelpunkt der Forschung und Entwicklung des Betonstraßenbaus in Deutschland. In den vergangenen Jahren wurden die vorteilhaften Oberflächenperformances derartiger Texturen, wie z.B. Griffigkeit, Ebenheit, Lärmminderung, in zahlreichen Forschungsprojekten umfassend untersucht. Im Kontext des gegenwärtig verfolgten ganzheitlichen performanceorientierten Ansatzes liegt der Fokus nun verstärkt auf der Analyse und Charakterisierung der Oberflächentopografie von Grinding- bzw. Groovingtexturen. Insbesondere gilt ein Hauptaugenmerk hierbei der zeitlichen Entwicklung der Oberflächentexturen in Abhängigkeit von äußeren Einwirkungen durch Klima und Verkehr.
Im Rahmen eines von der Bundesanstalt für Straßenwesen (BASt) geförderten Forschungsvorhabens wurden zunächst die messtechnischen Voraussetzungen für eine hochaufgelöste dreidimensionale Erfassung der Oberflächentopografie von Grinding- und Groovingtexturen in situ geschaffen. Das schließt auch die Entwicklung einer Messanordnung, die eine Wiederholbarkeit der 3D-Messungen gewährleistet und somit die Erfassung der zeitlichen Texturveränderungen ermöglicht. Basierend darauf wurden Auswerteroutinen zur qualitativen und quantitativen Beschreibung der Oberflächentexturen und deren Veränderungen entwickelt und angewandt. Anschließend wurde der Zustand von Grinding- und Groovingtexturen an ausgewählten Praxisstrecken in definierten Zeitintervallen erfasst. Unter Verwendung der erarbeiteten Auswerteroutinen wurden die erfassten Oberflächen analysiert und repräsentative Texturkennwerte abgeleitet.
T2 - Forschungskolloquium Betonstraßenbau
CY - Dresden, Germany
DA - 19.01.2023
KW - Betonfahbahndeckentexturen
KW - Grinding
KW - 3D-Laserscanning
KW - Datenanalyse
KW - Grooving
PY - 2023
AN - OPUS4-56896
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Frei, Vivian
A1 - Pirskawetz, Stephan
A1 - Thiele, Marc
A1 - Rogge, Andreas
T1 - Ermüdungsverhalten von Beton für unterschiedliche Probekörpergeometrien
N2 - Die zunehmende Anwendung hochfesten Betons in ermüdungsbelasteten Bauwerken, herausfordernde Belastungsszenarien im Bereich von On- und Offshore Windenergieanlagen bezüglich sehr hoher Lastwechselzahlen sowie das gleichzeitige Streben nach energie- und ressourcenschonendem Bauen stellen die Bemessung von Beton gegen Ermüdung vor neue Aufgaben. Eine Vielzahl von Studien beschreibt bereits die Auswirkung von Einflussfaktoren wie Mischungszusammensetzung, Feuchte, Probekörpergröße oder Belastungsart auf die Ermüdungsfestigkeit und den Ermüdungsprozess. Aufgrund der unterschiedlichen Geometrien und Mischungen der in den verschiedenen Studien verwendeten Proben sind die Auswirkungen der Einflussfaktoren jedoch kaum miteinander vergleichbar. In dem vom Bundesministerium für Wirtschaft und Klimaschutz (BMWK) geförderten Verbundprojekt WinConFat wurden deshalb verschiedene Einflussfaktoren gezielt an Proben mit einheitlichen Mischungen untersucht. Das durch die Bundesanstalt für Materialforschung und -prüfung (BAM) bearbeitete Teilprojekt fokussierte sich auf den „Einfluss der Probengeometrie und -größe auf die Ermüdung von Beton“. Neben der Erhebung von Daten zur Ermüdungsfestigkeit wurde der Ermüdungsprozess mit zerstörungsfreien Prüf- und Messmethoden untersucht. Diese Prüfmethoden wurden auch hinsichtlich ihrer Anwendbarkeit zur Erfassung der ermüdungsbedingten Schädigungsentwicklung an Betonbauwerken im Rahmen von Monitoringkonzepten bewertet. Untersucht wurden die Ermüdungsfestigkeiten und der Ermüdungsprozess an Zylindern mit drei unterschiedlichen Betonmischungen sowie unterschiedlicher Größe und Schlankheit. Die Ergebnisse dieser Untersuchungen werden im Folgenden vorgestellt und diskutiert.
KW - Ermüdung
KW - Hochfester Beton
KW - Probengröße
KW - Probengeometrie
PY - 2024
VL - 644
SP - 1
EP - 135
PB - Beuth
CY - Berlin
AN - OPUS4-59647
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Grabenkorrosion: Wie wissenschaftliche Diskussion eine Lösung ergibt. Und aktuelle Schäden durch Ignoranz
N2 - In den 1990er Jahren traten ungewöhnliche Schäden an verzinkten Stahlrohren auf, für die ein Mechanismus zunächst nicht bekannt war. Die Diskussion führte zur Beschreibung des Mechanismus, der bereits in den 1970er Jahren beschrieben wurde. Nach etwa 20 Jahren treten die Schäden erneut auf, weil die Ursache erneut ignoriert wird.
T2 - Sitzung GfKORR AK Schadensuntersuchung
CY - Berlin, Germany
DA - 09.04.2024
KW - Grabenkorrosion
KW - C-Stahl
PY - 2024
AN - OPUS4-61843
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Brass under stress
N2 - Different failure cases concerning brass alloys are discussed. The main connection is tensile stress due to processing in drinking water installations. The causes of the failures are discussed, solutions are given.
T2 - Kormat 2024
CY - Zagreb, Croatia
DA - 10.04.2024
KW - Brass
KW - Corrosion
KW - Drinking water
PY - 2024
AN - OPUS4-61844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Korrosion an Rohren aus ferritischem Stahl 1.4521: Untersuchungen an Trinkwasserinstallationen mit Spaltkorrosion an Pressverbindungen
N2 - Schäden durch Spaltkorrosion an Trinkwasserrohren aus 1.4521 werden diskutiert. Zur Ermittlung der Ursachen werden elektrochemische Versuche sowie das Korropad eingesetzt und Untersuchungen der Oberflächen gezeigt.
T2 - Sitzung GfKORR AK Schadensuntersuchung
CY - Berlin, Germany
DA - 09.03.2024
KW - Spaltkorrosion
KW - Trinkwasser
KW - Nichtrostender Stahl
PY - 2024
AN - OPUS4-61842
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Anwendungen von maschinellem Lernen und KI an der BAM
N2 - Im Austausch mit den anderen Bundesoberbehörden wurden die KI-Ansätze der verschiedenen Bundesoberbehörden zu spezifischen Themen der Nanowissenschaften präsentiert. Der Vortrag der BAM fokusiert sich auf die Themen "Self driving lab", semantische Segmentierung und Auswertung von elektronenmikroskopischen Bildern sowie die Generierung von ausführbaren Machineninstruktionen aus natürlicher Sprache. Abschließend wird der neue BAM DataStore vorgestellt.
T2 - Nano-Behördenklausur 2024
CY - Berlin, Germany
DA - 03.07.02024
KW - Nano
KW - Bundesoberbehörden
KW - Künstliche Intelligenz
KW - Neuronale Netzwerke
KW - Elektronisches Laborbuch
PY - 2024
AN - OPUS4-61819
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voigt, Marieke
A1 - von Werder, Julia
A1 - Meng, Birgit
ED - Middendorf, B.
ED - Fehling, E.
T1 - Microstructure analysis of thermally treated ultra high performance concrete in the context of the durability performance
N2 - Ultra high performance concrete (UHPC) is known for its high compressive strength of more than 150 MPa and its high durability. Thermal treatment at 90°C can accelerate the strength development so that the 28-days-strength can be achieved immediately after the treatment and an additional increase up to 30 % in some cases. The reason for the strength development is an accelerated hydration of the clinker minerals and an intensified pozzolanic reaction leading to a denser microstructure.
In previous research inhomogeneities in form of a zonation after unprotected thermal treatment were observed and analysed in respect to changes in the microstructure. This zonation is defined by a different microstructure in the core compared to the outer zone in the matter of porosity, mineral phase composition and a significant change in the potassium and sulphur concentration of the zones is measurable.
To isolate different transport mechanisms responsible for these element distributions UHPC samples were thermally treated at 90 °C and the microstructure was investigated under dry conditions and after immersion in water to investigate the influence of dehydration during and rehydration after the thermal treatment on the microstructure. Through durability testing via water absorption, water vapour diffusion, permeability testing and sulfuric acid resistance transport mechanisms like diffusion, migration, capillary suction are under investigation in correlation with the microstructure analysis. For the microstructure analysis measurements with µXRF, mercury intrusion porosity, XRD and SEM were conducted.
T2 - HiPerMat 2020
CY - Kassel, Germany
DA - 11.03.2020
KW - UHPC
KW - Thermal treatment
KW - Zonation
KW - Transport mechanism
KW - Durability
PY - 2020
SN - 978-3-7376-0828-2
DO - https://doi.org/10.17170/kobra-202002271026
VL - 23
SP - 151
EP - 152
PB - Kassel University Press
CY - Kassel
AN - OPUS4-52373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
T1 - Tutorial: NDE Reliability and the Influence of Human Factors
N2 - Human factors significantly influence the reliability of non-destructive testing (NDT) systems, impacting safety, efficiency, and cost. This tutorial explores the interplay between human capabilities, organizational context, and technological systems in NDT inspections. It starts with a short overview of reliability models, including the Probability of Detection (POD) framework, alongside with advanced approaches for reliability assessment. The distinction between human factors and human error is emphasized, advocating a systemic approach to human error that addresses underlying organizational and environmental conditions. The implications of increasing automation and AI integration are discussed, highlighting the challenges of trust, usability, and skill preservation in human-AI collaboration. Practical strategies, including user-centered design, targeted training, and risk management frameworks, are proposed to enhance inspection performance and maintain NDT reliability in evolving technological landscapes. This tutorial underscores the critical role of human factors in the transition to NDT 4.0 and the development of effective human-machine systems.
T2 - USES2 Training week#2
CY - Berlin, Germany
DA - 24.06.2024
KW - Human Factors
KW - Non-Destructive Testing
KW - Reliability
KW - Human-Machine Interaction
KW - Artificial Intelligence
PY - 2024
AN - OPUS4-61874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voigt, Marieke
A1 - von Werder, Julia
A1 - Meng, Birgit
T1 - Investigation of the zonation of thermally treated ultra high performance concrete
N2 - Ultra high performance concrete (UHPC) is characterised by its high compressive strength of more than 120 MPa and its high durability. With thermal treatment at 90°C, hydration is accelerated and a strength comparable to the 28-day strength can be achieved immediately after the treatment. In applying Optimum process conditions, the strength can be even further increased by up to 30%. Previous Research showed that thermal treatment can lead to inhomogeneities in form of a visible zonation within the cross-section, if the UHPC is not protected sufficiently from desiccation. This led to the question, to what extent the related changes in mechanical properties, microstructure and phase composition are of relevance for the performance of the UHPC. First investigations of small specimens thermally treated without protection exhibited a decrease of compressive strength, indicating that the zonation aspect requires further research.
In this study the zonation of UHPC treated thermally at 90°C is investigated after applying four different procedures of treatment and curing in comparison. The samples are characterized with respect to their chemistry, mineral composition and microstructure to allow an assessment on durability and strength development, with focus on potential depth dependent changes associated with the zonation.
The measurements reveal the formation of a visible zonation in case of unprotected treatment, if followed by immersion in water. The compressive strength is not significantly impaired, but a decrease in bending strength gives reason for concern. Further results allow clear correlation with changes in pore structure, whereas the interpretation of relationships with phase distribution, degree of hydration, microchemistry is more complex and therefore, provides only partial clarification.
KW - UHPC
KW - Thermal treatment
KW - Zonation
KW - Desiccation
KW - Microstructure
KW - Durability
PY - 2020
DO - https://doi.org/10.1016/j.conbuildmat.2020.119187
VL - 254
SP - 119187
PB - Elsevier Ltd.
AN - OPUS4-50828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Beltran, R.
A1 - Frei, Vivian
A1 - Marx, S.
T1 - Ultraschallprüfungen zur Erfassung der Schädigungsentwicklung unter verschiedenen Umweltbedingungen und unter zyklischer Druckschwellbelastung
N2 - Derzeit ist die Instandhaltung von großen Betontragwerken wie Brücken oder Windenergieanlagen problemorientiert und von einem reaktiven Vorgehen geprägt. Das bedeutet, erst wenn sichtbare Schäden vorliegen, werden diese meist unter Beeinträchtigung des Betriebs instand gesetzt. Im Hinblick auf die Entwicklung von prädiktiven Instandhaltungsstrategien, deren Fokus in der langfristigen Bauwerksüberwachung und der Vorhersage von Schädigungsentwicklungen liegt, wurde die Anwendung von Ultraschallverfahren für die Identifizierung der Degradationsprozesse von Betontragwerken unter Ermüdungsbeanspruchung untersucht. Hierzu fanden Arbeiten im vom Bundesministerium für Wirtschaft und Klimaschutz (BMWK) geförderten Verbundprojekt WinConFat zum "Einfluss der Probengeometrie und -größe auf die Ermüdung von Beton" an der Bundesanstalt für Materialforschung und -prüfung (BAM) und zu den "Methoden zur Zustandsanalyse von Windenergieanlagen" am Institut für Massivbau (IfMa) der Leibniz Universität Hannover (LUH) statt, welches zudem vom Deutschen Beton- und Bautechnik Verein e.V. (Forschungsvorhaben DBV-311) gefördert wurde. Dabei wurden verschiedene Einflussfaktoren auf die Schädigungsentwicklung unter Ermüdungsbeanspruchung wie die Probekörpergröße, das Belastungsniveau und die Betonfestigkeit untersucht. Als Schädigungsindikator und Vergleichsparameter wurden die Ultraschallgeschwindigkeit und der dynamische E-Modul des Betons verwendet. Um das Potential der Schädigungserfassung im Beton mittels Ultraschallprüfung umfassender zu bewerten, wurden zusätzlich Versuche an Betonproben unter monoton steigender Belastung, Kriechversuche, Temperaturversuche und Untersuchungen an großformatigen Balken durchgeführt.
KW - Ultraschallprüfung
KW - Ermüdung
KW - Hochfester Beton
PY - 2024
SN - 978-3-410-65917-4
SN - 0171-7197
VL - 651
SP - 1
EP - 102
PB - Beuth
CY - Berlin
AN - OPUS4-59801
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Schmidt, Alexandra
A1 - Bresch, Harald
A1 - Kämpf, K.
A1 - Bachmann, V.
A1 - Peters, T.
A1 - Kuhlbusch, T.
T1 - Development of a specific OECD Test Guideline on Particle Size and Particle Size Distribution of Nanomaterials
N2 - In this research project, a new OECD Test Guideline (TG) for the determination of “Particle Size and Particle Size Distributions of Nanomaterials” was developed as the existing OECD TG 110 is considered to be outdated in terms of applicable size range (not covering sizes <200 nm) and methods. By its scope with an applicable size range from 1 to 1000 nm the new Test Guideline (TG PSD) covers the whole nanoscale. The TG PSD is applicable for particulate and fibrous nanomaterials. The prescribed, pairwise measurement of fibre diameter and length in the TG PSD allows for the first time to differen-tiate fibres with regard to their size-dependent hazard properties. Measurement instructions for each included method were validated within two separated interlaboratory comparisons, as a distinction between near spherical particles and fibres when applying the methods has to be made.
Besides information on content and structure of the TG PSD, this final report outlines essential steps, considerations and organisational aspects during the development of the TG. Insights into the selec-tion, preparation and prevalidation of test materials used in the interlaboratory comparison are given. Finally, main results of the interlaboratory comparisons and their impacts on the TG PSD are pre-sented.
N2 - Im Rahmen des Forschungsprojekts wurde eine neue OECD-Prüfrichtlinie (TG) für die Bestimmung von Partikelgrößen und Partikelgrößenverteilungen von Nanomaterialien entwickelt, da die existie-rende OECD TG 110 zur Bestimmung von Partikelgrößen in Bezug auf den anwendbaren Größenbe-reich und die gegebenen Methoden veraltet ist bzw. den Nanometerbereich < 200 nm nicht abdeckt. Mit ihrem Anwendungsbereich von 1 bis 1000 nm deckt die neue Prüfrichtlinie (TG PSD) die gesamte Nanoskala ab. Die TG PSD ist für partikel- und faserförmige Nanomaterialien anwendbar. Durch die, in der TG PSD vorgeschriebene, paarweise Messung von Faserdurchmesser und -länge ermöglicht diese TG zum ersten Mal Fasern hinsichtlich ihrer größenabhängigen Gefahrstoffeigenschaften zu unter-scheiden. Die Messanweisungen aller enthaltenen Methoden wurden im Rahmen von zwei getrennten Ringversuchen validiert, da bei der Anwendung der Methoden eine Unterscheidung zwischen Parti-keln und Fasern gemacht werden muss.
Neben Angaben zum Inhalt und Struktur der TG PSD, befasst sich der vorliegende Abschlussbericht mit den wesentlichen Schritten, Überlegungen und organisatorischen Aspekten bei der Entwicklung der Prüfrichtlinie. Darüber hinaus werden Einblicke in die Auswahl, Vorbereitung und Prävalidierung der im Ringversuch verwendeten Testmaterialien gegeben. Schließlich werden die wichtigsten Ergeb-nisse aus den Ringversuchen und ihre Auswirkungen auf die TG PSD vorgestellt.
KW - Nano
KW - OECD
KW - Particle size distribution
KW - Testguideline
KW - Nanoparticle
PY - 2021
VL - 2021
SP - 1
EP - 47
PB - German Environment Agency
CY - Dessau
AN - OPUS4-54021
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Babutzka, Martin
A1 - Valet, Svenja
A1 - Kotula, Stefan
A1 - Burkert, Andreas
A1 - Gümmer, K.
A1 - Bender, S.
A1 - Huckshold, M.
T1 - Normentwurf für ein Prüfverfahren zur Bestimmung von Deckschichtwiderständen an Zinküberzügen mittels gelartiger Elektrolyte
N2 - Das Grundproblem der heute verfügbaren und normativ geregelten Prüfverfahren für Zinküberzüge besteht neben den realitätsfernen Prüfbedingungen vor allem in der subjektiv geprägten Auswertung der Prüfergebnisse. Die systematische Betrachtung der Entwicklungen der letzten Jahre zeigt, dass die üblichen Verfahren den aktuellen Anforderungen damit schon vom Ansatz her nicht gerecht werden können und auch die bisher betriebene, fortlaufende Variation und Anpassung von Prüfbedingungen keinen grundlegend neuen Lösungsansatz bieten können. Ein solcher ergibt sich nur, wenn die Zinküberzüge hinsichtlich der kinetischen Eigenschaften der Deckschichtbildung und -auflösung umfassend beschrieben werden können, was nur durch den Einsatz elektrochemischer Untersuchungsmethoden mittels Gelelektrolyten möglich ist.
Aus diesem Grund wurde im Verbundforschungsvorhaben GELELEK auf der Basis elektrochemischer Methoden unter Verwendung eines Gelelektrolyten ein Normenvorschlag für eine Prüfnorm erarbeitet und zur Normungsreife geführt, welcher den Anforderungen an ein Messsystem für Feldanwendungen entspricht.
Im Verbundforschungsvorhaben GELELEK wurde eine gezielte Kombination von Laboruntersuchungen mit Untersuchungen im Feld und Bauteilen unter realen Einsatzbedingungen angestrebt. Randbedingungen für eine gesicherte Messung von atmosphärisch bewitterten Zinküberzügen unter Einsatz von Gelelektrolyten wurden erarbeitet und im Normenvorschlag festgeschrieben. Darüber hinaus wurde ein mobiles Messgerät für Messungen mit Gelelektrolyten an realen Bauteilen entwickelt. Nach Abschluss des Forschungsvorhabens steht Industrievertretern und Prüfinstituten ein wissenschaftlich gesichertes Messverfahren basierend auf Kennwerten zur Verfügung, um Zinküberzüge und deren momentane Schutzwirkung unter praxisrelevanten Bedingungen einschätzen und normativ geregelt prüfen zu können.
Der vorliegende Forschungsbericht gibt einen Überblick über die Motivation zur Durchführung des Forschungsvorhabens, wichtige Arbeitsschritte, Details zur entwickelten Prüfmethode sowie Einsatzmöglichkeiten für Prüfinstitute und Unternehmen.
KW - Normung
KW - Zink
KW - Korrosion
KW - Deckschichtbildung
KW - Atmosphärische Korrosion
KW - Korrosionsprüfung
PY - 2022
UR - https://www.gav-verzinken.de/forschung/wissenspool
SP - 1
EP - 24
AN - OPUS4-54947
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Piquemal, François
A1 - Hoffmann, Johannes
A1 - Gautier, Brice
A1 - Hertwig, Andreas
A1 - Frabricius, Norbert
T1 - Publishable Summary for 20IND12 Elena Electrical nanoscale metrology in industry
N2 - Consumer electronics, innovative quantum technologies, and Internet of Things applications all rely on semiconductors, where reliable characterisation of electrical properties at the nanoscale is essential for European innovation and competitiveness. The measurement of these properties allows the evaluation of critical parameters used to define the performance of electronic materials and components. Currently, Conductive Atomic Force Microscopes and Scanning Microwave Microscopes enable nanoscale electrical characterisation, but they are costly, complicated and, in many cases where they are used, unreliable as measurements are not traceable. The aim of the project was to make such measurements traceable for the first time, with stated uncertainties, and affordable by developing and testing cost effective instrumentation and the first “out of lab” reference standards from DC to GHz and by elaborating robust calibration methods and good practice guides using simplified uncertainty budgets. All the objectives were achieved. The project has successfully improved the user-friendly uncertainty quantification for the electrical measurements at the nanoscale in the industrial environment. The design of calibration standards has been improved and new standards for DC resistance / current as well as HF impedance have been introduced and quantified. Good practice guides for the calibration and uncertainty quantification have been written and will be available to the users’ community. New ways of determining the properties of standard samples like ellipsometry have been evaluated. The interaction with stakeholders and industry collaborators was very important for the consortium and several case studies were carried out with industry-relevant samples. All data, procedures, and example uncertainty data from the project are included into the standardisation process and two IEC standards projects have been started during this project. These standards will be used as one important dissemination ways for the results of the project.
KW - Electrical Properties
KW - Nanometrology
KW - Scanning Probe Microscopy
KW - Optical Surface Analysis
PY - 2024
SP - 1
EP - 9
AN - OPUS4-61812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bresch, Harald
A1 - Schmidt, Alexandra
A1 - Kämpf, K.
A1 - Bachmann, V.
A1 - Peters, T.
A1 - Kuhlbusch, T.
T1 - Draft OECD Test Guideline for the Testing of Chemicals - Particle Size and Particle Size Distribution of Nanomaterials
N2 - Final Draft of the OECD Test Guideline for Particle Size and Particle Size Distribution of Nanomaterials.
The OECD Working Party on Manufactured Nanomaterials (WPMN) has actively worked towards understanding possible safety issues for manufactured nanomaterials and has contributed significantly to resolving these by developing Test Guidelines, Guidance Documents, Test Reports and other publications with the aim of a safe use of manufactured nanomaterials. The OECD website (www.oecd.org/science/nanosafety) and the referenced publications contain more background information.
Among others, the OECD Test Guideline “Particle Size Distribution/Fibre Length and Diameter Distributions” (TG 110, adopted in 1981) was identified to require an update to address the specific needs of manufactured nanomaterials as the TG 110 is currently only valid for particles and fibres with sizes above 250 nm. The WPMN prioritised to either update TG 110 to be applicable also to particles at the nanoscale or draft a new nanomaterial specific Test Guideline (TG). Eventually, it was decided to develop a new TG for particle size and particle size distribution measurements of nanomaterials covering the size range from 1 nm to 1000 nm for further justification. This TG overlaps with TG 110 in the size range from 250 nm to 1000 nm. When measuring particulate or fibrous materials, the appropriate TG should be selected depending on the size range of particles tested. In line with TG 110, the new TG for nanomaterials includes separate parts for particles and fibres. For the part of this TG which addresses particles, several methods applicable to nanomaterials were reviewed and included to take into account developments since 1981 when the TG110 was adopted. This TG includes the following methods: Atomic Force Microscopy (AFM), Centrifugal Liquid Sedimentation (CLS)/Analytical Ultracentrifugation (AUC), Dynamic Light Scattering (DLS), Differential Mobility Analysis System (DMAS), (Nano)Particle Tracking Analysis (PTA/NTA), Small Angle X-Ray Scattering (SAXS), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM).
For measuring the diameter and length of fibres, analysing images captured with electron microscopy is currently the only method available. This TG includes Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).
To test the validity of this TG, an ILC was performed. Test materials were chosen to reflect a broad 68 range of nanomaterial classes, e.g. metals, metal oxides, polymers and carbon materials. Where possible, well-characterised test materials were used. Additionally, the test materials were chosen, so that they reflect a broad range of sizes representing the size range 1 nm to 1000 nm and finally,
for fibres only, aspect ratios from length/diameter of 3 to > 50.
KW - Nano
KW - OECD
KW - Test guideline
KW - Nanomaterial
KW - Nanoparticle
PY - 2021
UR - https://www.oecd.org/chemicalsafety/testing/draft-test-guideline-particle-size-distribution-nanomaterials.pdf
SP - 1
PB - Organisation for Economic Co-operation and Development
CY - Paris
AN - OPUS4-53828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bresch, Harald
A1 - Schmidt, Alexandra
A1 - Kämpf, K.
A1 - Bachmann, V.
A1 - Peters, T.
A1 - Kuhlbusch, T.
T1 - Test Guideline No. 125 - Nanomaterial Particle Size and Size Distribution of Nanomaterials
N2 - The OECD Working Party on Manufactured Nanomaterials (WPMN) has actively worked towards understanding possible safety issues for manufactured nanomaterials and has contributed significantly to resolving these by developing Test Guidelines, Guidance Documents, Test Reports and other publications with the aim of a safe use of manufactured nanomaterials. To address the specific needs of manufactured nanomaterials, the OECD Test Guideline No. 110 “Particle Size Distribution/Fibre Length and Diameter Distributions” was identified as one of the test guidelines (TGs) to require an update. The current TG 110 (adopted in 1981) is only valid for particles and fibres with sizes above 250 nm. The WPMN prioritised to either update TG 110 to be applicable also to particles at the nanoscale or draft a new nanomaterial specific (TG).
Eventually, it was decided to develop a new TG that covers the size range from 1 nm to 1000 nm, intended for particle size and particle size distribution measurements of nanomaterials. Paragraph 11 provides further justification on the need for such measurements for nanomaterials. This TG overlaps with TG 110 in the size range from 250 nm to 1000 nm. When measuring particulate or fibrous materials, the appropriate TG should be selected depending on the size range of particles tested. In line with TG 110, the new TG for nanomaterials includes separate parts for particles and fibres.
For the part of this TG which addresses particles, several methods applicable to nanomaterials were reviewed and included to take into account developments since 1981 when the TG 110 was adopted. This TG includes the following methods: Atomic Force Microscopy (AFM), Centrifugal Liquid Sedimentation (CLS)/Analytical Ultracentrifugation (AUC), Dynamic Light Scattering (DLS), Differential Mobility Analysis System (DMAS), (Nano)Particle Tracking Analysis (PTA/NTA), Small Angle X-Ray Scattering (SAXS), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The method Single Particle Inductively Coupled Plasma Mass Spectrometry (sp-ICP-MS) could not be sufficiently validated within the interlaboratory comparison (ILC) carried out for the different methods in this TG (see also paragraph 6 for further details on the ILC). Applicability of sp-ICP-MS is strongly limited to nanomaterials with high mass values in combination with a sufficiently high particle size. However, the general method ICP-MS is widely used and the sp-mode for the size measurement of specific nanomaterials was successfully performed in ILCs elsewhere. The method is therefore included in the Appendix Part C of this TG, which further details the limitations of sp-ICP-MS.
For measuring the diameter and length of fibres, analysing images captured with electron microscopy is currently the only method available. This TG includes Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).
To test the validity of this TG, an ILC was performed. Test materials were chosen to reflect a broad range of nanomaterial classes, e.g. metals, metal oxides, polymers and carbon materials. Where possible, well-characterised test materials were used.
Additionally, the test materials were chosen to reflect a broad range of sizes representing the size range 1 nm to 1000 nm. Specifically for fibres, a broad range of aspect ratios was included (length/diameter of 3 to > 50). Some of the test materials used are commercially available and further references are given in the validation report of the ILC. Sample preparation for physical chemical characterisation is critical for all listed methods. Due to the differences between individual nanomaterials and due to the wide range of individual material properties it is impossible to have a generic protocol to obtain the best possible sample preparation for every nanomaterial. Therefore, a generic protocol on sample preparation is not part of this TG. Information on sample preparation is given in the paragraphs 25-29, 33, 34 and 39 for particles and in paragraphs 159) for fibres. Further information on sample preparation of nanomaterials for physical chemical characterisation can be found in the OECD Guidance on Sample Preparation and Dosimetry for the Safety Testing of Manufactured Nanomaterials and elsewhere.
KW - Nano
KW - Nanomaterial
KW - Nanoparticle
KW - OECD
KW - Test guideline
PY - 2022
DO - https://doi.org/10.1787/20745753
SP - 1
EP - 72
PB - Organisation for Economic Co-operation and Development
CY - Paris
AN - OPUS4-55191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Xiangju
A1 - Huang, Yanliang
A1 - Li, Jianzheng
A1 - Yang, Dan
A1 - Xu, Yong
A1 - Kunte, Hans-Jörg
T1 - Effect of microbial hydrogen consumption on the hydrogen permeation behaviour of AISI 4135 steel under cathodic protection
N2 - The feasibility of microbial hydrogen consumption to mitigate the hydrogen embrittlement (HE) under different cathodic potentials was evaluated using the Devanathan-Stachurski electrochemical test and the hydrogen permeation efficiency h. The hydrogen permeation efficiency h in the presence of strain GA-1 was lower than that in sterile medium. The cathodic potential inhibited the adherence of strain GA-1 to AISI 4135 steel surface, thereby reducing the hydrogen consumption of strain GA-1. The adherent GA-1 cells were capable of consuming ‘cathodic hydrogen’ and reducing the proportions of absorbed hydrogen, indicating that it is theoretically possible to control HE by hydrogen-consuming microbes.
KW - Energy Engineering and Power Technology
KW - Condensed Matter Physics
KW - Fuel Technology
KW - Renewable Energy, Sustainability and the Environment
PY - 2020
DO - https://doi.org/10.1016/j.ijhydene.2019.12.058
SN - 1879-3487
VL - 45
IS - 7
SP - 4054
EP - 4064
PB - Elsevier BV
CY - New York, NY
AN - OPUS4-59319
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Böhning, Martin
T1 - Dataset of comprehensive Full-notch creep tests (FNCT) of selected high-density polyethylene (PE-HD) materials
N2 - The dataset provided in this repository comprises data obtained from a series of full-notch creep tests (FNCT) performed on selected high-density polyethylene (PE-HD) materials (for further details, see section 1 Materials in this document) in accordance with the corresponding standard ISO 16770.
The FNCT is one of the mechanical testing procedures used to characterize polymer materials with respect to their environmental stress cracking (ESC) behavior. It is widely applied for PE-HD materials, that are predominantly used for pipe and container applications. It is based on the determination of the time to failure for a test specimen under constant mechanical load in a well-defined and temperature controlled liquid environment. The test device used here also allows for continuous monitoring of applied force, specimen elongation and temperature.
KW - Polyethylene
KW - Environmental Stress Cracking
KW - Full-notch creep test
KW - PE-HD
KW - Crack growth
PY - 2023
DO - https://doi.org/10.5281/zenodo.10143351
PB - Zenodo
CY - Geneva
AN - OPUS4-58835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Bonse, Jörn
A1 - Kirner, Sabrina V.
A1 - Krüger, Jörg
ED - Sugioka, K.
T1 - Laser-induced periodic surface structures (LIPSS)
N2 - Laser-induced periodic surface structures (LIPSS) are a universal phenomenon and can be generated on almost any material by irradiation with linearly polarized radiation. This chapter reviews the current state in the field of LIPSS, which are formed in a “self-ordered” way and are often accompanying materials processing applications. LIPSS can be produced in a single-stage process and enable surface nanostructuring and, in turn, adaption of optical, mechanical, and chemical surface properties. Typically, they feature a structural size ranging from several micrometers down to less than 100 nm and show a clear correlation with the polarization direction of the light used for their generation. Various types of LIPSS are classified, relevant control parameters are identified, and their material-specific formation mechanisms are analyzed for different types of inorganic solids, i.e., metals, semiconductors, and dielectrics. Finally, technological applications featuring surface functionalization in the fields of optics, fluidics, medicine, and tribology are discussed.
KW - Femtosecond laser
KW - Laser ablation
KW - Laser-induced periodic surface structures (LIPSS)
KW - Microstructures
KW - Nanostructures
PY - 2021
SN - 978-3-319-69537-2
DO - https://doi.org/10.1007/978-3-319-69537-2_17-2
SP - 1
EP - 59
PB - Springer Nature
CY - Cham, Switzerland
ET - 2
AN - OPUS4-51493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, Yanliang
A1 - Liu, Xiangju
A1 - Zhang, Qichao
A1 - Xu, Yong
A1 - Kunte, Hans-Jörg
A1 - De Marco, Roland
T1 - Hydrogen release from carbon steel in chloride solution under anodic polarization
N2 - The hydrogen permeation current increase was noticed for carbon steel in 0.5 mol/L NaCl solution under strong anodic potentials, which is contrary to the common understanding. Hydrogen permeation under cathodic potentials has been widely studied because of possible hydrogen embrittlement failures of high strength steels in seawater, but investigations of anodic polarization on hydrogen permeation are fairly rare, as the hydrogen evolution reaction shall be retarded. To corroborate the observed phenomenon, experiments were conducted using both as-received and vacuum-annealed sheet specimens. It was verified that the observed phenomena originated from the released hydrogen in traps by metal dissolution under anodic polarization.
KW - Energy Engineering and Power Technology
KW - Condensed Matter Physics
KW - Fuel Technology
KW - Renewable Energy, Sustainability and the Environment
PY - 2020
DO - https://doi.org/10.1016/j.ijhydene.2019.11.218
SN - 1879-3487
VL - 45
IS - 4
SP - 3307
EP - 3315
PB - Elsevier BV
CY - New York, NY
AN - OPUS4-59322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Y.
A1 - Gruner, A.
A1 - Aboud, D. G. K.
A1 - Bonse, Jörn
A1 - Schille, J.
A1 - Loeschner, U.
A1 - Kietzig, A.-M.
T1 - Polarization effects on laser-inscribed angled micro-structures
N2 - The polarization of the laser beam exhibits more substantial differences in laser micromachining as the angle of incidence deviates from zero. In the reported work, our focus was to explore the effects of circularly, p- and s-polarized laser on angled ultrashort pulse laser micromachining of micropillar arrays. The examination encompassed laser process factors, including angles of incidence, microstructure dimensions, and inter-pillar spacing. A comparison between the resulting structures demonstrated that p-polarized laser beam was the most efficient in material removal in angled laser micromachining, followed by circularly polarized laser. While the s-polarized beam exhibited the lowest ablation efficiency among the three. Such distinction is mainly attributed to the distinguishing reflectivity of the three states of polarization on tilted planes. The development of structural heights during ablation processes was examined, and potential defects in laser processing methodologies were interpreted. The dependency of structural heights on inter-pillar spacing was analyzed. This study bridges the gap between existing studies on angled ultrashort pulse laser machining and the influences of polarization on laser machining. The comparison between structures produced using laboratory-scale and industrial-scale laser systems also yielded pertinent recommendations for facilitating a smooth transition of angled laser micromachining from laboratory-scale research to industrial applications.
KW - Laser processing
KW - Laser-induced periodic surface structures (LIPSS)
KW - Microstructures
KW - Nanostructures
PY - 2024
UR - https://www.sciencedirect.com/science/article/pii/S0169433223028714
DO - https://doi.org/10.1016/j.apsusc.2023.159191
SN - 0169-4332
VL - 649
SP - 1
EP - 15
PB - Elsevier
AN - OPUS4-59329
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rolle, Annette
A1 - Neumeyer, Tino
T1 - Prüfung und Zulassung von radioaktiven Stoffen in besonderer Form
N2 - Radioaktive Stoffe in besonderer Form (SFRM) sind nicht dispergierbare feste radioaktive Stoffe oder dichte Kapseln, die radioaktive Stoffe enthalten /1/. SFRM sind eine Kategorie innerhalb der verkehrsrechtlichen Vorschriften. Für die Beförderung zu Anwendern in der Industrie, Medizin und Forschung werden umschlossene radioaktive Stoffe (Strahler) gemäß ihrem aktivitätsabhängigen Gefahrenpotenzial verpackt. Strahler mit einer hohen Aktivität (> A2) erfordern entsprechend der verkehrsrechtlichen Vorschriften eine Beförderung in Typ B (U) Versandstücken, die als unfallsicher gelten. Alternativ besteht bis zu einer Aktivität < A1 die Möglichkeit der Beförderung in nicht unfallsicheren Typ A Versandstücken, wenn die Strahler nachweislich unfallsicher ausgelegt sind und eine Zulassung als SFRM vorliegt.
Die Bundesanstalt für Materialforschung und –prüfung (BAM) ist gemäß GGVSEB §8 (2) /2/ in Deutschland die zuständige Behörde für die Prüfung und Zulassung radioaktiver Stoffe in besonderer Form.
KW - Zulassung
KW - Radioaktiv
KW - Beförderung
KW - Strahlenschutz
PY - 2020
SN - 0947-434 X
IS - 1
SP - 14
EP - 16
PB - TÜV Media
CY - Köln
AN - OPUS4-50763
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Kuchenbecker, Petra
A1 - Lindemann, Franziska
T1 - Particle size determination of a commercially available CeO2 nano powder - SOPs and reference data
N2 - Compilation of detailed SOPs for characterization of a commercially available CeO2 nano powder including
- suspension preparation (indirect and direct sonication),
- particle size determination (Dynamic Light Scattering DLS and Centrifugal Liquid Sedimentation CLS) with reference data, respectively.
For sample preparation and analysis by Scanning Electron Microscopy (SEM) of this powder see related works (submitted, coming soon).
KW - Wet dispersion
KW - Nano powder
KW - Particle size
KW - CeO2
KW - Ceria
KW - DLS
KW - CLS
PY - 2023
DO - https://doi.org/10.5281/zenodo.10061079
PB - Zenodo
CY - Geneva
AN - OPUS4-58785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Kuchenbecker, Petra
A1 - Lindemann, Franziska
T1 - SOP and reference data for determination of the Volume-specific Surface Area (VSSA) of a commercially available CeO2 nano powder
N2 - Detailed SOP and reference data for the determination of the VSSA of a commercially available CeO2 nano powder:
specific (BET-) Surface Area by gas adsorption (Ar and N2)
skeletal (true solid state) density by gas pycnometry.
Estimation of the particle size by VSSA screening method.
KW - Nano powder
KW - VSSA
KW - Volume specific surface area
KW - Screening method
KW - Ceria
KW - CeO2
PY - 2023
DO - https://doi.org/10.5281/zenodo.10061235
PB - Zenodo
CY - Geneva
AN - OPUS4-58786
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - BP150: Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement by Monte-Carlo based particle scattering Simulations
N2 - Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of radiation damage in biomolecules and tissue.
To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined. Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented. We apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications
with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared.
Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus.
T2 - DPG Frühjahrstagung
CY - Dresden, Germany
DA - 26.03.2023
KW - AuNP
KW - Beta decay
KW - Brachytherapy
KW - Cancer treatment
KW - Clustered nanoparticles
KW - DNA
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - LEE
KW - Livermore model
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - OH radical
KW - Penelope model
KW - Radiation damage
KW - Radiation therapy
KW - Radiationtherapy
KW - Radioactive decay
KW - Radiolysis
KW - Radiotherapy
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
KW - Beta particle
KW - Particle scattering
KW - Protein
KW - Proteins
PY - 2023
AN - OPUS4-57253
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bulling, Jannis
A1 - Jurgelucks, B.
A1 - Prager, Jens
A1 - Walther, A.
T1 - Experimental validation of an inverse method for defect reconstruction in a two-dimensional waveguide model
N2 - Defect reconstruction is essential in non-destructive testing and structural health monitoring with guided ultrasonic waves. This paper presents an algorithm for reconstructing notches in steel plates, which can be seen as artificial defects representing cracks by comparing measured results with those from a simulation model. The model contains a parameterized notch, and its geometrical parameters are to be reconstructed. While the algorithm is formulated and presented in a general notation, a special case of guided wave propagation is used to investigate one of the simplest possible simulation models that discretizes only the cross section of the steel plate. An efficient simulation model of the plate cross section is obtained by the semi-analytical scaled boundary finite element method. The reconstruction algorithm applied is gradient-based, and algorithmic differentiation calculates the gradient. The dedicated experimental setup excites nearly plane wave fronts propagating orthogonal to the notch. A scanning laser Doppler vibrometer records the velocity field at certain points on the plate surface as input to the reconstruction algorithm. Using two plates with notches of different depths, it is demonstrated that accurate geometry reconstruction is possible.
KW - Ultrasound
KW - Waveguides
KW - Symbolic computation
KW - Optimization problems
PY - 2024
DO - https://doi.org/10.1121/10.0025469
SN - 0001-4966
VL - 155
IS - 6
SP - 3794
EP - 3806
PB - Acoustical Society of America (ASA)
AN - OPUS4-60325
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn Setsuko
A1 - Kim, Hyunho
A1 - Pascavis, Madeleine
A1 - Cha, Baekdong
A1 - Brambilla, Gabriel
A1 - Cho, Young Kwan
A1 - Park, Jinho
A1 - Vilela, Raquel R. C.
A1 - de Camargo, Andrea S. S.
A1 - Castro, Cesar M.
A1 - Lee, Hakho
T1 - Upconverting Nanoparticle-based Enhanced Luminescence Lateral-Flow Assay for Urinary Biomarker Monitoring
N2 - Development of efficient portable sensors for accurately detecting biomarkers is crucial for early disease diagnosis, yet remains a significant challenge. To address this need, we introduce the enhanced luminescence lateral-flow assay, which leverages highly luminescent upconverting nanoparticles (UCNPs) alongside a portable reader and a smartphone app. The sensor’s efficiency and versatility were shown for kidney health monitoring as a proof of concept. We engineered Er3+- and Tm3+-doped UCNPs coated with multiple layers, including an undoped
inert matrix shell, a mesoporous silica shell, and an outer layer of
gold (UCNP@mSiO2@Au). These coatings synergistically enhance emission by over 40-fold and facilitate biomolecule conjugation, rendering UCNP@mSiO2@Au easy to use and suitable for a broad range of bioapplications. Employing these optimized nanoparticles in lateral-flow assays, we successfully detected two acute kidney injury-related biomarkers-kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL)-in urine samples. Using our sensor platform, KIM-1 and NGAL can be accurately detected and quantified
within the range of 0.1 to 20 ng/mL, boasting impressively low limits of detection at 0.28 and 0.23 ng/mL, respectively. Validating our approach, we analyzed clinical urine samples, achieving biomarker concentrations that closely correlated with results obtained via ELISA. Importantly, our system enables biomarker quantification in less than 15 min, underscoring the performance of our novel UCNP-based approach and its potential as reliable, rapid, and user-friendly diagnostics.
KW - Biosensor
KW - Upconverting nanoparticles
KW - Lateral flow
KW - Portable sensor
KW - Kidney injury
PY - 2024
DO - https://doi.org/10.1021/acsami.4c06117
SN - 1944-8244
VL - 16
IS - 29
SP - 38243
EP - 38251
PB - American Chemical Society (ACS)
AN - OPUS4-60689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenck, Johanna-Maria
A1 - Frenck, Georg
A1 - Degener, Sebastian
A1 - Vollmer, Malte
A1 - Niendorf, Thomas
T1 - Interrelationships of stress-induced martensitic phase transformation and pitting corrosion in iron-based shape memory alloys
N2 - Orientation dependence of stress-induced martensitic transformation under compression and the influence of a corrosion attack on superelastic properties were investigated for Fe42.7Mn34.7Al13.4Ni7.7Cr1.5 (at.−%) single crystals. The results of incremental strain tests show that the crystallographic orientation has a considerable impact on the superelastic performance, eventually resulting from the formation of twinned or detwinned martensite to accommodate strain as well martensite variant interaction. In order to investigate the effect of a corrosive environment on the mechanical performance and martensitic transformation, compression specimens were immersed in a 5.0 wt.−% NaCl solution for 24 h before tested in incremental strain tests. The immersion of the compression specimens revealed a partial surface corrosion attack including localized pitting corrosion. The localized corrosion attack increased the number of active martensite plates, most probably due to an induced multiaxial stress state. Further investigations on specimens subjected to −6% compressive strain revealed that areas with retransformed martensite serve as nucleation zones for corrosion damage. Stress-induced corrosion cracks developed, which eventually deteriorate functional response.
KW - Shape memory alloy (SMA)
KW - In situ characterization
KW - Corrosion
KW - Austenite-to-martensite phase transformation
PY - 2024
DO - https://doi.org/10.1016/j.mtla.2023.102001
VL - 33
SP - 1
EP - 11
PB - Elsevier BV
AN - OPUS4-61283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iannuzzi, Maurizio
A1 - Chowdhary, Suvrat
A1 - Fiedler, Holly
A1 - Haoues, Kilian
A1 - Schade, Boris
A1 - Thünemann, Andreas
A1 - Quaas, Elisa
A1 - Koksch, Beate
T1 - Rational design of polyfluorinated peptide-based materials: Self-assembly of an amphiphilic motif
N2 - Generation of a pH sensitive amphiphilic block oligopeptide containing the bioactive function RGD and a library of derivatives varying the length of the hydrophobic core and the degree of side chain fluorination. Peptide rational design enables us to obtain desired features (pH sensitivity etc.). The introduction of fluorine alters a wide range of peptide properties such as secondary structure propensity, folding, thermal and metabolic stability and proteolytic resistance. The RGD function is highly effective at promoting the attachment of numerous cell types to a plethora of materials. This small sequence is the principal integrin-binding domain present within ECM proteins such as fiobronectin, vibronectin and fibrinogen. For this reason, RGD containing peptides offer several advantages for biomaterials applications. The use of RGD compared with native ECM proteins, minimized the risk of immune reactivity or pathogen transfer. Herein in this work, we present the peptide motif X6RGD and its fluoro-derivates for prospective receptor-specific drug delivery in cancer theraphy. Overall, our results demonstrate that high degree of fluorination achieved triggers a selective modification of peptide self-assembly dramatically improving the structural properties, the carrier suitability, enzimatic degradation profiles and cytotoxic features of the fluoropeptide conjugate(s).
T2 - 37th European Peptide Symposium
CY - Florence, Italy
DA - 25.08.2024
KW - Nanostructure
KW - SAXS
KW - Small-angle X-ray scattering
PY - 2024
SN - 1099-1387
VL - 30
IS - S2
SP - 247
EP - 248
PB - Wiley
CY - New York, NY
AN - OPUS4-62191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte Bernardino, Carolina
T1 - Metal-Ion Loaded Silica Nanoparticles as Antimicrobial Coatings for Safer High-Touch Surfaces
N2 - Not only since the Covid-19 pandemic have researchers focused their efforts on high touch surfaces to minimize the contraction of infectious diseases due to human contact. To help prevent the spread of infectious pathogens, surfaces and coatings are designed to minimize the presence or survivability of pathogens on surfaces in various settings, including healthcare centers, long-term care facilities, public transport, schools, and businesses. Extensive research has focused on finding solutions to prevent bacterial transmission and biofilm formation by killing or reducing the attachment of microbes. These solutions include surface-bound active antimicrobials, biocidal coatings, and passive pathogen-repellent surfaces, developed using nanomaterials, chemical modifications, and micro- and nano-structuring.
Nanomaterials are a prime candidate for such a solution. Here, we developed mesoporous silica nanoparticles (MSNs) loaded with antimicrobially active silver and copper ions that can be used in sprayable formulations as surface coatings. The influence of different surface functionalization and metal ion loadings on the efficacy of these sprayable coatings was studied. Amine- (MSN-NH2), carboxy- (MSN-COOH) and thiol-functionalized mesoporous silica nanoparticles (MSN-SH) were synthesized and characterized using different techniques, such as transmission electron microscopy (TEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), dynamic light scattering (DLS), electrophoretic light scattering (Zeta potential measurements) and nitrogen sorption measurements.
After loading MSNs with antimicrobially active silver or copper ions, the nanoparticle dispersions were spray-coated on stainless steel substrates that were primed with sprayable polyelectrolyte solutions to enhance coating homogeneity and nanoparticle adhesion. The metal ion release was analyzed by Inductively coupled plasma optical emission spectroscopy (ICP-OES). The antimicrobial properties of the nanoparticle suspension and the coatings were tested against three commonly found pathogenic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli as well as a fungal pathogen, Candida albicans. The toxicity of the coatings against human skin cells was also assessed.
T2 - STOP Antimicrobial Coatings Conference
CY - Mons, Belgium
DA - 05.12.2024
KW - Mesoporous Silica Nanoparticles
KW - Antimicrobial Coatings
KW - Spray-Coating
KW - Pathogens
PY - 2024
AN - OPUS4-62180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ruehle, Bastian
T1 - Natural language processing for automated workflow and knowledge graph generation in self-driving labs
N2 - Natural language processing with the help of large language models such as ChatGPT has become ubiquitous in many software applications and allows users to interact even with complex hardware or software in an intuitive way. The recent concepts of Self-Driving Labs and Material Acceleration Platforms stand to benefit greatly from making them more accessible to a broader scientific community through enhanced user-friendliness or even completely automated ways of generating experimental workflows that can be run on the complex hardware of the platform from user input or previously published procedures. Here, two new datasets with over 1.5 million experimental procedures and their (semi)automatic annotations as action graphs, i.e., structured output, were created and used for training two different transformer-based large language models. These models strike a balance between performance, generality, and fitness for purpose and can be hosted and run on standard consumer-grade hardware. Furthermore, the generation of node graphs from these action graphs as a user-friendly and intuitive way of visualizing and modifying synthesis workflows that can be run on the hardware of a Self-Driving Lab or Material Acceleration Platform is explored. Lastly, it is discussed how knowledge graphs – following an ontology imposed by the underlying node setup and software architecture – can be generated from the node graphs. All resources, including the datasets, the fully trained large language models, the node editor, and scripts for querying and visualizing the knowledge graphs are made publicly available.
KW - Natural Language Processing
KW - Large Language Models
KW - Self-Driving Labs
KW - Materials Acceleration Platforms
KW - Workflows
KW - Nanomaterials
KW - Advanced Materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631947
UR - https://github.com/BAMresearch/MAPz_at_BAM/tree/main/Minerva-Workflow-Generator
DO - https://doi.org/10.1039/d5dd00063g
SN - 2635-098X
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
A1 - Bulling, Jannis
A1 - Lugovtsova, Yevgeniya
A1 - Zeipert, Henning
A1 - Prager, Jens
A1 - Henning, Bernd
ED - van Keulen, Wim
ED - Kok, Jim
T1 - On the repulsion effect of coupled Lamb wave modes
N2 - Lamb waves, recognized for their significance in material characterisation, structural health monitor-ing, and non-destructive testing, exhibit complex behaviours that are crucial for industrial applica-tions. This paper delves into the mathematical and physical principals of the repulsion effect that can be observed in the dispersion curves of coupled Lamb wave modes. This effect is the result from the mechanical coupling of thin-walled solid plates and prevents the crossing of the dispersion curves. The study employs the Scaled Boundary Finite Element Method to calculate the dispersion curves of coupled plates and to simulate their interaction for a weak and ideal coupling. Through a mathemati-cal framework and a physical analogy with simple harmonic oscillators, the paper elucidates the un-derlying principals of this effect. Furthermore, the paper highlights the practical significance of the repulsion effect in Lamb waves, suggesting its application for testing and monitoring the integrity of multi-layer structures like adhesive bonds, which are important for various industrial applications. A deepened understanding of this effect could contribute to the enhancement of non-destructive evalua-tion techniques.
T2 - ICSV 2024
CY - Amsterdam, The Netherlands
DA - 08.07.2024
KW - Scaled Boundary Finite Element Method (SBFEM)
KW - Lamb waves
KW - Mode repulsion
KW - Mechanical coupling
KW - Dispersion curves
PY - 2024
SN - 978-90-90-39058-1
SN - 2329-3675
SP - 410
EP - 418
PB - The International Institute of Acoustics and Vibration (IIAV)
CY - Amsterdam
AN - OPUS4-62855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
A1 - Bulling, Jannis
A1 - Lugovtsova, Yevgeniya
A1 - Zeipert, Henning
A1 - Prager, Jens
A1 - Henning, Bernd
T1 - On the repulsion effect of coupled Lamb wave modes
N2 - This work investigates the phenomenon of mode repulsion in coupled Lamb wave systems. By mechanically coupling two dissimilar plates using spring elements, it is shown that previously intersecting Lamb wave modes are repelled, avoiding any crossing in the dispersion curves. The effect, rooted in eigenvalue theory and first observed in quantum systems, is explained through both mathematical models and classical analogies with coupled harmonic oscillators. Numerical simulations using the Scaled Boundary Finite Element Method validate the theoretical predictions, revealing a correlation between strain distribution and frequency splitting. The observed mode repulsion provides new insights into interface properties and offers potential for applications such as monitoring adhesive degradation in layered structures.
T2 - DAGA 2024
CY - Hannover, Germany
DA - 18.03.2024
KW - Scaled Boundary Finite Element Method (SBFEM)
KW - Lamb waves
KW - Mode repulsion
KW - Mechanical coupling
KW - Dispersion curves
PY - 2024
SP - 632
EP - 635
AN - OPUS4-62854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schultheiß, Annika L.
A1 - Kruschwitz, Sabine
A1 - Wilsch, Gerd
A1 - Bogner, Andreas
A1 - Patel, Ravi
T1 - Lessons learnt on quantitative spatial chloride analysis using LIBS and μXRF
N2 - Understanding chloride ingress is crucial in the context of the durability of concrete structures against corrosion. Techniques such as Laser-Induced Breakdown Spectroscopy (LIBS) and Micro X‑ray Fluorescence (µXRF) can provide a 2D representation of chloride ingress. However, obtaining quantitative data from such techniques is not a trivial task. In this study, we focus on factors such as sample preparation, measurement settings, calibration strategy, and post-processing of results which directly affect the outcome of the experiments but are rarely discussed in the literature.
T2 - Rilem Annual Week 2024
CY - Toulouse, France
DA - 25.08.2024
KW - Chloride ingress
KW - LIBS, µXRF
KW - Imaging
KW - Nondestructive testing
KW - Durability
PY - 2024
AN - OPUS4-61663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Small-angle scattering for everyone: How to unlock the power of this ancient technique
N2 - The obscure, yet fundamental technique of scattering can unlock essential information on the fine structure of materials. For you, it can help you understand how your batteries charge, how squid backbones work, or how hundreds of small variations in your syntheses affect your samples.
As a nondestructive technique, it also measures your materials *in situ* or operando, as you pull it, heat it, electrify it, or align it one way or another. Scattering can be done using light, X-rays, neutrons, and even electrons, giving you the choice on which probe is best for you. The only downside? Scattering will always remain a complicated technique to do right.
The technique gives you only one piece of information: the length distribution of density in your sample. How you interpret this (rather abstract) piece of information is up to you and your samples. Unlike microscopy, where the real-space image can be interpreted almost intuitively and artefacts are easier to spot, in scattering you cannot always easily identify artefacts. Therefore, the only way to do scattering experiments correctly is through rigour and care. For those of us with that particular eccentricity, seeing the rigour and care pay off is exhilarating, and opens the door to a life of happiness and excitement.
This lecture will introduce scattering (in particular using X-rays and neutrons), what it is, what you can (and cannot) get out of it, and how to approach your scattering experiment. Regarding the experimental section, it will discuss the five parts that make up a successful scattering experiment based on real-life examples:
Preparation: which and how you prepare your samples affects what you can get out of the interpretation
Measurement: The machine design and your measurement choices dictates the final quality of your data
Correction: Obtaining trustworthy scattering curves will greatly improve the speed and quality of your analysis.
Analysis: Do you linearize, use generic scattering models, perform classical least-squares fitting, play with Monte-Carlo analysis or transform your data.. Some tips to help you make a choice.
Interpretation: what does the analysis of all your samples tell you? Can you fit the puzzle pieces together to form a piece of knowledge?
For further information, please feel free to explore the https://lookingatnothing.com/ weblog, the https://youtube.com/drheaddamage video channel, or by asking me in person or by email for specific questions at brian.pauw@bam.de . Some introductory reading can be found in the following papers:
Pauw, B. R. (2013): Everything SAXS: small-angle scattering pattern collection and correction. _J. Phys.: Condens. Matter_ 25: 383201. DOI: [10.1088/0953-8984/25/38/383201](http://dx.doi.org/10.1088/0953-8984/25/38/383201)
B. R. Pauw, A. J. Smith, T. Snow, N. J. Terrill, A. F. Thünemann, (2017): The modular SAXS data correction sequence for solids and dispersions, _Journal of Applied Crystallography_, 50: 1800–1811, DOI: [10.1107/S1600576717015096](https://doi.org/10.1107/S1600576717015096)
G. J. Smales, B. R. Pauw (2021): The MOUSE project: a meticulous approach for obtaining traceable, wide-range X-ray scattering information. _Journal of instrumentation_ 16 (6) P06034. DOI: [10.1088/1748-0221/16/06/P06034](https://doi.org/10.1088/1748-0221/16/06/P06034)
T2 - SAS School at the XIX International Small Angle Scattering Conference
CY - Taipei, Taiwan
DA - 02.11.2024
KW - X-ray scattering
KW - Neutron scattering
KW - Scattering
KW - X-ray
KW - Neutron
KW - Introduction
KW - Methodology
PY - 2024
AN - OPUS4-61623
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kühnel, Alena
A1 - Stelzner, Ludwig
A1 - Weise, Frank
T1 - Measurement and analysis of concrete pavement surface textures using hand-held 3D laser scanning technology
N2 - Concrete pavement surface textures are divided by means of their dimension into four categories: microtexture, macrotexture, megatexture and roughness. They influence the most important performance characteristics of road surfaces, such as friction (also referred to as “skid resistance”), tire/pavement noise, evenness and surface drainage. These properties are relevant for driving safety, comfort and environmental aspects. Up to now, research in Germany has focused on monitoring these characteristics by tire/pavement noise and skid resistance measurements. However, the topography of surface textures has not been sufficiently investigated and evaluated until now. The development and availability of high-performance, hand-held 3D scanning systems during the last years enable measurements of the microtexture and macrotexture of concrete pavement surfaces at short measuring times and high resolution.
This paper shows the ability of modern laser-based technology to record three-dimensional data of different concrete pavement surface textures in situ. For this purpose, a special measuring frame has been developed. The presented results were primarily obtained within the framework of a research project commissioned by the German Federal Highway Research Institute (BASt) and processed by the Federal Institute for Materials Research and Testing. Various concrete pavement surface textures by means of diamond grinding and hybrid of diamond grinding and grooving were investigated in situ. In addition, exposed aggregate concretes (EAC), which were introduced as a standard type of concrete for motorway pavements in Germany in 2006, have been analyzed. Based on the gathered 3D data, evaluation routines for qualitative and quantitative analysis have been developed and applied. The aim was to derive the statistical parameters such as the relative and cumulative frequency distribution of the profile depth as well as the roughness coefficient for diamond ground pavements and EAC. Also, the “mean profile depth” (MPD) as a common texture-related parameter was determined.
T2 - 14th International Symposium on Concrete Roads
CY - Krakow, Poland
DA - 25.06.2023
KW - Concrete pavement surface textures
KW - 3D Laser Scanning
KW - Diamond Grinding
KW - Exposed aggregate concrete
KW - Data analysis
KW - Surface characteristics
PY - 2023
SP - 1
EP - 14
AN - OPUS4-57893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
A1 - Simon, Sebastian
A1 - Meng, Birgit
T1 - Internal sulfate resistance of concrete
N2 - If the amount of sulfate within the mix design for concrete is not balanced, ettringite formation which first controls solidification continues while the concrete is hardening. Ettringite forms by reaction of sulfate contained in the cement or in some admixture with calcium aluminate (C3A) as cement component. The “late primary ettringite formation” promotes an increase in volume within the hardened concrete leading to cracks. To analyze the effect of substituting part of ordinary Portland cement (OPC) by a treated brown coal fly ash mortar bars were tested according to ASTM C452. This test method was originally developed to extrapolate from the internal to external sulfate attack and is based on the idea that by testing a concrete mixture containing sulfate the process of deterioration is accelerated because it does not have to diffuse into the concrete before reaction first. In addition to the samples prescribed in ASTM C452 further samples in the size of the German SVA procedure were tested also designed for accessing the external sulfate resistance. The results show that while the replacement of 25 % of cement by brown coal fly ash leads to length changes around the limit defined by ASTM, the substitution of 50 % cement exceeded the limit by a multiple. The progress of expansion is the very similar for the two geometries tested. In-situ XRD measurements confirmed that while for pastes made of OPC the formation of ettringite is completed after 20 hours, this is not true for the mixtures containing the brown coal fly ash.
In a different study the effect of hydrothermal treatment on the phase composition of ultra-high-performance concrete was analyzed. The results show that the sulfate and aluminate resulting from the decomposition of ettringite are bound into new phases.
If this binding is permanent this might allow the larger use of sulfate bearing raw materials.
T2 - EuroCoalAsh 2021 Conference
CY - Online meeting
DA - 02.11.2021
KW - Brown coal fly ash
KW - Ettringite
KW - Internal sulfate resistance
KW - Test methods
KW - In-situ XRD
KW - Hydrothermal treatment
PY - 2021
SP - 131
EP - 137
CY - Thessaloniki
AN - OPUS4-54133
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Advanced Coating Materials
N2 - This book by Scrivener Publishing contains 14 chapters written by 82 leading scientists, experienced in the field of coatings. They demonstrate mechanisms, usage and manipulation of cutting‐edge coating methods. Each chapter is well structured and ends with a conclusion, highlighting the content. The book is divided into 3 parts: “Materials and Methods”, “Coating Materials Nanotechnology” and “Advanced Coating Technology and Applications”.
Finally, this book provides a comprehensive insight into innovative research in advanced coating materials and state‐of‐the‐art technologies, without being a real textbook. It fulfills its intension of being beneficial both for technicians and scientists.
KW - Corrosion
KW - Coating
KW - Protection
PY - 2020
DO - https://doi.org/10.1002/maco.202070044
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 4
SP - 675
EP - 676
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stratakis, E.
A1 - Bonse, Jörn
A1 - Heitz, J.
A1 - Siegel, J.
A1 - Tsibidis, G.D.
A1 - Skoulas, E.
A1 - Papadopoulos, A.
A1 - Mimidis, A.
A1 - Joel, A.-C.
A1 - Comanns, P.
A1 - Krüger, Jörg
A1 - Florian, C.
A1 - Fuentes-Edfuf, Y.
A1 - Solis, J.
A1 - Baumgartner, W.
T1 - Laser engineering of biomimetic surfaces
N2 - The exciting properties of micro- and nano-patterned surfaces found in natural species hide a virtually endless potential of technological ideas, opening new opportunities for innovation and exploitation in materials science and engineering. Due to the diversity of biomimetic surface functionalities, inspirations from natural surfaces are interesting for a broad range of applications in engineering, including phenomena of adhesion, friction, wear, lubrication, wetting phenomena, self-cleaning, antifouling, antibacterial phenomena, thermoregulation and optics. Lasers are increasingly proving to be promising tools for the precise and controlled structuring of materials at micro- and nano-scales. When ultrashort-pulsed lasers are used, the optimal interplay between laser and material parameters enables structuring down to the nanometer scale. Besides this, a unique aspect of laser processing technology is the possibility for material modifications at multiple (hierarchical) length scales, leading to the complex biomimetic micro- and nano-scale patterns, while adding a new dimension to structure optimization. This article reviews the current state of the art of laser processing methodologies, which are being used for the fabrication of bioinspired artificial surfaces to realize extraordinary wetting, optical, mechanical, and biological-active properties for numerous applications. The innovative aspect of laser functionalized biomimetic surfaces for a wide variety of current and future applications is particularly demonstrated and discussed. The article concludes with illustrating the wealth of arising possibilities and the number of new laser micro/nano fabrication approaches for obtaining complex high-resolution features, which prescribe a future where control of structures and subsequent functionalities are beyond our current imagination.
KW - Biomimetic surfaces
KW - Laser processing
KW - Surface functionalization
KW - Bioinspiration
KW - Bionic materials
PY - 2020
DO - https://doi.org/10.1016/j.mser.2020.100562
SN - 0927-796X
VL - 141
SP - 100562-1
EP - 100562-47
PB - Elsevier B.V.
AN - OPUS4-50927
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Mezera, Marek
A1 - Florian, C.
A1 - Römer, G.-W.
A1 - Krüger, Jörg
A1 - Bonse, Jörn
ED - Stoian, R.
ED - Bonse, Jörn
T1 - Creation of Material Functions by Nanostructuring
N2 - Surface nanostructures provide the possibility to create and tailor surface functionalities mainly via controlling their topography along with other chemical and physical material properties. One of the most appealing technologies for surface functionalization via micro- and nanostructuring is based on laser processing. This can be done either via direct contour-shaping of the irradiated material using a tightly focused laser beam or in a self-ordered way that allows employing larger laser beam diameters along with areal scanning to create a variety of laser-induced periodic surface structures (LIPSS). For the latter approach, particularly ultrashort pulsed lasers have recently pushed the borders across long-lasting limitations regarding the minimum achievable feature sizes and additionally boosted up the production times. This chapter reviews the plethora of recently investigated applications of LIPSS—for example, via imposing diffractive or plasmonic structural colors, the management of liquids and surface wetting properties, biomedical and bioinspired functionalities, beneficial effects in tribology for reducing friction and wear, the manipulation of optical scattering and absorption in photovoltaics, or the modification of magnetic or superconducting surface properties in other energy applications. The footprint of the LIPSS-based technology is explored in detail regarding the current state of industrialization, including an analysis of the market and associated LIPSS production costs.
KW - Laser-induced periodic surface structures, LIPSS
KW - Surface functionalization
KW - Nanostructures
KW - Microstructures
KW - Laser processing
PY - 2023
SN - 978-3-031-14751-7
SN - 978-3-031-14752-4
DO - https://doi.org/10.1007/978-3-031-14752-4_23
VL - 239
SP - 827
EP - 886
PB - Springer Nature Switzerland AG
CY - Cham, Switzerland
AN - OPUS4-57295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Sokolowski-Tinten, K.
A1 - Bonse, Jörn
A1 - Barty, A.
A1 - Chapman, H.N.
A1 - Bajt, S.
A1 - Bogan, M.J.
A1 - Boutet, S.
A1 - Cavalleri, A.
A1 - Düsterer, S.
A1 - Frank, M.
A1 - Hajdu, J.
A1 - Hau-Riege, S.
A1 - Marchesini, S.
A1 - Stojanonovic, N.
A1 - Treusch, R.
ED - Stoian, R.
ED - Bonse, Jörn
T1 - In-Situ Observation of the Formation of Laser-Induced Periodic Surface Structures with Extreme Spatial and Temporal Resolution
N2 - Irradiation of solid surfaces with intense ultrashort laser pulses represents a unique way of depositing energy into materials. It allows to realize states of extreme electronic excitation and/or very high temperature and pressure and to drive materials close to and beyond fundamental stability limits. As a consequence, structural changes and phase transitions often occur along unusual pathways and under strongly nonequilibrium conditions. Due to the inherent multiscale nature—both temporally and spatially—of these irreversible processes, their direct experimental observation requires techniques that combine high temporal resolution with the appropriate spatial resolution and the capability to obtain good quality data on a single pulse/event basis. In this respect, fourth-generation light sources, namely, short wavelength and short pulse free electron lasers (FELs), are offering new and fascinating possibilities. As an example, this chapter will discuss the results of scattering experiments carried out at the FLASH free electron laser at DESY (Hamburg, Germany), which allowed us to resolve laser-induced structure formation at surfaces on the nanometer to submicron length scale and in temporal regimes ranging from picoseconds to several nanoseconds with sub-picosecond resolution.
KW - Laser-induced periodic surface structures, LIPSS
KW - Capillary waves
KW - Time-resolved scattering
KW - Pump-probe experiments
KW - Free electron laser
PY - 2023
SN - 978-3-031-14751-7
SN - 978-3-031-14752-4
DO - https://doi.org/10.1007/978-3-031-14752-4_6
VL - 239
SP - 257
EP - 276
PB - Springer Nature Switzerland AG
CY - Cham, Switzerland
AN - OPUS4-57297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Giese, Marcel
T1 - Experimentelle Charakterisierung der WIG-Schweißeignung einer Hoch- und Mediumentropie-Legierung
N2 - Equiatomic multi-element systems with defined entropy are a relatively new mate-rial concept for alloy production. These alloys consist of at least five elements in equiatomic distribution in the case of high entropy alloys (HEA) and three to four elements in equiatomic distribution in the case of medium entropy alloys (MEA). Previous studies on these alloys have focused primarily on their production, micro-structure and the resulting material properties. Meanwhile, the focus here is on the processing of the alloys and their influence on future applications. Up to now, there has been insufficient knowledge of the materials and processes involved in weld-ing.
In this work, therefore, the weldability of a CoCrFeMnNi-HEA and a CoCrNi-MEA by means of a TIG welding process was investigated as a basic system. To this end, the welding parameters were first determined on a reference alloy (Ni-based: 2.4858) and transferred to the welding of the CoCrFeMnNi-HEA and CoCrNi-MEA. Weldability was assessed by testing the absence of defects and microstructures obtained. The weld metal exhibited the dendritic microstructure typical of TIG, with microsegregations forming as interdendritic phases. Increased hardness was de-tected in the weld metal compared to the base metal. In the heat-affected zone, there was little grain growth and, in both alloys, the formation of hot cracks after welding. The cause of the cracks was to be found in the specimen preparation, which had an influence on the subsequent processing. After elimination of this in-fluence, no welding process-related imperfections were found in the CoCrFeMnNi-HEA and CoCrNi-MEA.
In summary, both materials show good fusion weldability by TIG welding. The re-sults of this work thus contribute to the understanding of the weldability of HEA and in particular for CoCrNi-MEA, which was considered in this depth for the first time.
KW - WIG-Schweißen
KW - Hochentropielegierung
KW - Mediumentropielegierung
PY - 2021
SP - 1
EP - 79
CY - Otto von Guericke Universität
AN - OPUS4-53644
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Zvereva, V.
A1 - Martynova, S.
A1 - Asanov, I.
A1 - La Fontaine, C.
A1 - Roudenko, O.
A1 - Gubanov, A.
A1 - Plyusnin, P.
A1 - Korenev, S.
A1 - Asanova, T.
T1 - Insight of the thermal decomposition of ammonium hexahalogenoiridates(IV) and hexachloroiridate(III)
N2 - Thermal decomposition of (NH4)3[IrCl6]·H2O, (NH4)2[IrCl6] and (NH4)2[IrBr6] in reductive and inert atmospheres has been investigated in situ using quick-EXAFS and temperature-resolved powder X-ray diffraction. For the first time, (NH4)2[Ir(NH3)Cl5] and (NH4)2[Ir(NH3)Br5] have been proven as intermediates of thermal decomposition of (NH4)3[IrCl6]·H2O, (NH4)2[IrCl6] and (NH4)2[IrBr6]. Thermal degradation of (NH4)2[IrCl6] and (NH4)2[IrBr6] is a more complex process as suggested previously and includes simultaneous formation of (NH4)2[Ir(NH3)Cl5] and (NH4)2[Ir(NH3)Br5] intermediates mixed with metallic iridium. In the inert atmosphere, complexes (NH4)[Ir(NH3)2Cl4] and (NH4)[Ir(NH3)2Br4] as well as [Ir(NH3)3Br3] were proposed as possible intermediates before formation of metallic iridium particles
KW - Thermal decomposition
KW - Iridium compounds
KW - EXAFS
KW - In situ PXRD
PY - 2020
DO - https://doi.org/10.1039/D0CP02743J
VL - 22
IS - 40
SP - 22923
EP - 22934
AN - OPUS4-51224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zutta Villate, J. M.
A1 - Viviana Rojas, J.
A1 - Hahn, Marc Benjamin
A1 - Anselmo Puerta, J.
T1 - Synthesis of 198Au nanoparticles sub 10 nm due optimization on local dose by Monte Carlo simulations for cancer treatment
N2 - To enhance the biological effects of radiation damage in cancerous cells, we present an alternative approach to the use of gold nanoparticles (AuNP), focusing on the synthesis and characterization of highly monodisperse, spherical radioactive gold nanoparticles 198AuNP. The size of the AuNP size was optimized with the help of Geant4/TOPAS particle scattering simulations, and energy deposition per nm3 per decay for varying radii (2–10 nm) was evaluated. This work is the foundation for ongoing experimental work to evaluate cell death induced by 198AuNP which aims for the use of radioactive gold nanoparticles in cancer treatment.
KW - AuNP
KW - Beta decay
KW - Beta particle
KW - Brachytherapy
KW - Cancer treatment
KW - Nanoparticles
KW - Nanoparticle
KW - DNA
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Gamma ray
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - LEE
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - Synthesis
KW - TEM
KW - OH radicals
KW - Particle scattering
KW - Radiation damage
KW - Radiationtherapy
KW - Radioactive decay
KW - Radiolysis
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
PY - 2022
DO - https://doi.org/10.1007/s10967-022-08355-5
SN - 1588-2780
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-55132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Atomic force microscope study of friction at the submicron-scale during tribotests with self-mated steel
N2 - Friction at the microscale during reciprocal sliding tribotests was studied for the first time with self-mated steel (100Cr6/AISI 52100) taking advantage of an atomic force microscope (AFM). To this aim, microsized steel particles were glued to the AFM-cantilever and employed as colloidal tips to perform tribotests on a steel disc. The torsion of the cantilever, which correlates with the friction force, was measured during the tests. Few tests with the same load did not yield any wear and show that the load and adhesion contributions to friction stay constant when the shape of the test particle does not change. Most of the presented tribotests engendered wear. For those tests, the increase of friction during the tribotests was attributed to the emerging plowing contribution. Furthermore, analysis of both torsion and local slope gives information on the creation of wear particles and their influence on friction.
KW - Friction
KW - Microtribology
KW - Sliding
KW - Wear
PY - 2022
DO - https://doi.org/10.1115/1.4054251
VL - 144
IS - 10
SP - 1
EP - 9
PB - ASME
AN - OPUS4-54839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Zerbst, Uwe
A1 - Madia, Mauro
T1 - Bruchmechanische Bauteilbewertung
N2 - Die sichere Auslegung von Bauteilen kommt an der Anwendung bruchmechanischer Methoden heute nicht mehr vorbei. Das vorliegende Buch bietet eine Einführung in diese Methoden mit besonderen Schwerpunkten auf dem aktuellen Stand der bruchmechanischen Kennwertermittlung und den Methoden der analytischen bruchmechanischen Bauteilbewertung. Es beschreibt die Mechanismen von Risswachstum und Bruch, die grundlegenden Konzepte der Bruchmechanik, die analytische Ermittlung der Rissspitzenbelastung in Bauteilen sowie die Anwendung der Bruchmechanik in unterschiedlichen Kontexten. Der Schwerpunkt liegt dabei auf der praktischen Anwendung u. a. anhand von Demonstrationsbeispielen, die im Detail nachvollzogen werden können.
KW - Rissausbreitung
KW - Bruch
KW - Bruchmechanische Konzepte
KW - Bruchmechanische Kennwerte
KW - Rissspitzenbelastung
KW - Failure Assessment Diagram
KW - Rissschließfunktion
KW - Kritische Last
KW - J-Integral
KW - Risswiderstand
KW - Stretch-Zone
KW - IBESS-Prozedur
KW - Constraint faktor
KW - Mismatch
KW - Ligamentplastifizierung
KW - Crack Tip Opening Displacement (CTOD)
PY - 2022
SN - 978-3-658-36150-1
SN - 978-3-658-36151-8
DO - https://doi.org/10.1007/978-3-658-36151-8
SP - C1
EP - 372
PB - Springer
CY - Heidelberg
AN - OPUS4-56004
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaki, Mohammad
T1 - Nano- And Advanced Materials Synthesis In A Self-driving Lab (SDL)
N2 - Development of new nano- and advanced materials - or improvement of existing ones - are important drivers in materials research due to the high importance of these material classes for various applications. Traditional laboratory methods for material development often suffer from reproducibility issues, inefficiencies, human errors, and long experimental optimization times. To overcome these challenges and thus accelerate and optimize the process of material synthesis and discovery, we are building a Self-Driving Lab (SDL), in which we integrate robotics for autonomous nanomaterial synthesis, and automated characterization and data analysis for a complete and reliable nanomaterial synthesis workflow. We also leverage artificial intelligence (AI) and machine learning (ML) algorithms to analyze characterization results and plan new experiments to optimize material properties in an ML-guided active learning feedback loop.
Our SDL is very agnostic towards the types of nano- and advanced materials it can synthesize. On the same SDL platform, we successfully synthesized Stober silica, mesoporous silica, copper-oxide, and gold nanoparticles, as well as metal-organic frameworks and more complex structures from multi-step reactions, such as Au@SiO2 and CuO@SiO2 core-shell nanoparticles. All these material syntheses showed excellent reproducibility when run on the SDL platform multiple times.
Automated, in-line characterization measurements of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence) of the nanomaterials have also been incorporated in the SDL, along with automating data analysis of at-line or off-line characterization techniques such as electron microscopy image analyses [1]. Incorporating these characterization results alongside a machine learning feedback loop that suggests new experimental parameters for obtaining materials with target properties is a key step for developing autonomous, closed-loop optimization processes. In such a process, we typically start by using random sampling to suggest initial experimental parameters, followed by ML-guided active learning algorithms such as Bayesian optimization, artificial neural networks, or downhill simplex optimizers (e.g., Nelder-Mead) that suggest new synthesis parameters to finally arrive at a material with the targeted or enhanced properties. Further improvement and optimization of our SDL has the potential to mitigate challenges faced by traditional approaches and open a way for rapid and reproducible nano- and advanced material synthesis, optimization, and discovery.
T2 - ANAKON Conference 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Self-driving laboratories
KW - Materials acceleration platforms
KW - Nanomaterials
KW - Advanced materials
KW - Automation
KW - Robotics
KW - In-line characterization
PY - 2025
AN - OPUS4-62737
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Sustainable mechanochemical reaction engineering: from molecular mechanisms to scalable technology
N2 - In this talk, I will present about our quest to fundamentally understand mechanochemical reactions by in situ monitoring studies. Another of our interest is scaling up mechanochemistry. For example, we are now working on developing mechanochemical technology to enable a circular economy of plastics.
T2 - Korea-Germany Symposium on Mechanochemistry
CY - Jeonju, South Korea
DA - 02.10.2024
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2024
AN - OPUS4-62110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Mechanochemistry: fundamentals to application
N2 - In the first part, I will talk about the role of mechanochemistry in prebiotic chemistry. For example, prebiotically plausible pathways to peptides from inactivated amino acids are unclear as most oligomerization approaches rely on thermodynamically disfavored reactions in solution. I will show how a combination of mineral surfaces and mechanochemical activation enables the oligomerization of amino acids to oligopeptides (Figure 1). In the second part, I will show how fundamental studies inspired to use mechanochemistry for the sustainable synthesis of commercially relevant compounds, in line with the United Nations Sustainable Development Goals.2 We developed a solvent-free thermo-mechanochemical approach for the direct coupling of carboxylic acids and amines, which avoids activators and additives. We applied our methodology for the quantitative synthesis of the active pharmaceutical ingredient moclobemide (Figure 2).
T2 - Solutions in Chemistry Conference 2024
CY - Sveti Martin na Muri, Croatia
DA - 15.11.2024
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2024
AN - OPUS4-62111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwibbert, Karin
A1 - Richter, Anja
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Laser-Textured Surfaces: A Way to Control Biofilm Formation?
N2 - Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria-repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria-repellent surfaces lies in the contactless and aseptic large-area laser-processing of technical surfaces. Tailored surface textures, enabled by different laser-processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state-of-the-art review of laser-surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser-processed surfaces, the challenges of anti-microbial surface designs are discussed, and future directions will be outlined.
KW - Antibacterial surfaces
KW - Biofilms
KW - Laser processing
KW - Laser-induced periodic surface structures (LIPSS)
KW - Microbial adhesions
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588260
DO - https://doi.org/10.1002/lpor.202300753
SN - 1863-8899
SP - 1
EP - 41
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-58826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reuter, T.
A1 - Wohlgemuth, F.
A1 - Bellon, Carsten
A1 - Hausotte, T.
T1 - Measurement-based Detector Characteristics for Digital Twins in aRTist 2
N2 - Various software products for the simulation of industrial X-ray radiography have been developed in recent years (e.g., aRTist 2, CIVA CT, Scorpius XLab, SimCT, Wilcore) and their application potential has been shown in numerous works. However, full systematic approaches to characterise a specific CT system for these simulation software products to obtain a truthful digital twin are still missing. In this contribution, we want to present two approaches to obtain realistic grey values in X-ray projections in aRTist 2 simulations based on measured projections. In aRTist 2, the displayed grey value of a pixel is based on the energy density incident on that pixel.
The energy density is calculated based on the X-ray tube spectrum, the attenuation between source and detector as well as an energy-dependent sensitivity curve of the detector. The first approach presented in this contribution uses the sensitivity curve as a free modelling parameter. We measured the signal response at different thicknesses of Al EN-AW6082 at different tube voltages (i.e., different tube spectra). We then regarded the grey values displayed by these projections as a data regression respectively an optimisation problem and obtained the sensitivity curve that is best able to reproduce the measured behaviour in aRTist 2. The resulting sensitivity curve does not necessarily hold physical meaning but is able to simulate the real system behaviour in the simulation software.
The second approach presented in this contribution is to estimate the sensitivity curve based on assumptions about the characteristics of the scintillation detector (e.g., scintillator material, scintillator thickness and signal processing characteristics). For this approach, a linear response function (linear relationship between the deposited energy per pixel and the resulting grey value) is assumed. If the detector characteristics, which affect the simulated deposited energy, are properly modelled, the slope and offset of the response function to match the measured grey values should be the same for different tube spectra. As the offset is constant and given by the grey values measured at no incident radiation, the slope is the remaining parameter to evaluate the success of the detector modelling. We therefore adapted the detector characteristics by changing the detector setup until the slope was nearly the same for all measured tube spectra. We are aware that the resulting parameters of the scintillator material and thickness might not be the real ones, but with those modelling parameters we are able to simulate realistic grey values in aRTist 2. Both of those approaches could potentially be a step forward to a full systematic approach for a digital twin of a real CT system in aRTist 2.
T2 - 20th World Conference on Non-Destructive Testing (WCNDT 2024)
CY - Incheon, South Korea
DA - 27.05.2024
KW - Digital Twin
KW - Computed Tomography
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602046
DO - https://doi.org/10.58286/29910
SP - 1
EP - 10
PB - NDT.net
CY - Mayen, Germany
AN - OPUS4-60204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
T1 - Zerstörungsfreie Strukturaufklärung antiker Baudenkmäler des Pergamonmuseums
N2 - Das Pergamonmuseum ist eines der am meisten besuchten Museen Berlins. Es wird seit etwa 20 Jahren im Rahmen des 1999 von der Stiftung Preußischer Kulturbesitz beschlossenen Masterplans Museumsinsel schrittweise grundhaft instandgesetzt und um einen weiteren Flügel ergänzt, der 2025 fertig gestellt sein soll. In diesem Kontext wurde auch kurz nach dem Beschluss des Masterplans eine Bauzustandsanalyse an den in Originalgröße in der Antikensammlung ausgestellten Baudenk¬ mälern durchgeführt. Allerdings stellte man dabei fest, dass herkömmliche Erkundungsverfahren wie die Bauaufnahme, die baugeschichtliche Untersu¬ chung, das Quellenstudium sowie die äußerliche Begutachtung nicht ausreichen, um die innere Struktur der antiken Baudenkmäler hinreichend zu charakterisieren. Deshalb wurde die BAM im Jahr 2003 von der ARGE Pfanner Pergamonmuseum
beauftragt, in enger Zusammenarbeit mit zwei Ingenieurbüros, dem Ingenieurbüro Patitz (IGP) und der Gesellschaft für geophysikalische Unter¬ suchungen mbH (GGU) unter Hinzuziehung einer Restauratorin, die innere Struktur ausgewählter an¬ tiker Baudenkmäler zerstörungsfrei zu untersuchen. Das Ziel der zerstörungsfreien Strukturaufklärung zum inneren Aufbau der Bauteile war es, einerseits sicherheitsrelevante Informationen für die statische Nachweisführung bereitzustellen, sowie andererseits eine Planungsgrundlage für die eventuell erforder¬ liche Ertüchtigung der Baudenkmäler zu schaffen. Im Fokus der Untersuchungen standen dabei das Markttor von Milet und das Säulenjoch der Heiligen Halle am Markt von Priene1 • Im nachstehenden Beitrag werden exemplarisch die am Markttor von Milet durchgeführten Untersuchungen vorgestellt.
T2 - Workshop zur Kulturguterhaltung
CY - Berlin, Germany
DA - 17.11.2021
KW - Bauzustandsanalyse
KW - Radar
KW - Radiografie
PY - 2021
AN - OPUS4-54458
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stohl, Leonie
T1 - Bioreceptivity of Concrete Facades
N2 - In recent years, the demand for new and sustainable products has been constantly rising. Especially cementitious materials are known for their high carbon footprint and novel approaches will be needed to counterbalance that. The BAM departments 7.1 (building materials) and 4.0 (Material and the environment) try to improve the sustainability of concrete panels by establishing a biofilm on the weather protection layer. Using an ultra-high-performance-concrete allows the production of very thin facade tiles with a small carbon footprint. Furthermore, the durability of these tiles is expected to surpass the one of “normal” concrete facades and offer the possibility of modular renewing of defective tiles instead of a wall, or even remodeling a whole building. The controlled application of biofilms on facades aims to improve biodiversity, microclimate, and air quality in cities. Furthermore, the greening of typically gray surfaces could improve the mental health of the residents. The project focuses on testing a multiplicity of concrete samples, varying e.g., in roughness or pH. The bioreceptivity is analyzed via laboratory tests, as well as in perennial outdoor experiments.
T2 - Biology versus building materials: from biocides to bio-receptivity
CY - Online meeting
DA - 08.02.2022
KW - Bioreceptivity
KW - Algea
KW - Concrete
KW - Biofilm
PY - 2022
AN - OPUS4-54470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
A1 - Patitz, G.
A1 - Redmer, B.
A1 - Hübner, M.
T1 - Zerstörungsfreie Strukturaufklärung antiker Baudenkmäler des Pergamonmuseums
N2 - Das Pergamonmuseum ist eines der am meisten besuchten Museen Berlins. Es wird seit etwa 20 Jahren im Rahmen des 1999 von der Stiftung Preußischer Kulturbesitz beschlossenen Masterplans Museumsinsel schrittweise grundhaft instandgesetzt und um einen weiteren Flügel ergänzt, der 2025 fertig gestellt sein soll. In diesem Kontext wurde auch kurz nach dem Beschluss des Masterplans eine Bauzustandsanalyse an den in Originalgröße in der Antikensammlung ausgestellten Baudenk¬ mälern durchgeführt. Allerdings stellte man dabei fest, dass herkömmliche Erkundungsverfahren wie die Bauaufnahme, die baugeschichtliche Untersu¬ chung, das Quellenstudium sowie die äußerliche Begutachtung nicht ausreichen, um die innere Struktur der antiken Baudenkmäler hinreichend zu charakterisieren. Deshalb wurde die BAM im Jahr 2003 von der ARGE Pfanner Pergamonmuseum beauftragt, in enger Zusammenarbeit mit zwei Ingenieurbüros, dem Ingenieurbüro Patitz (IGP) und der Gesellschaft für geophysikalische Unter¬ suchungen mbH (GGU) unter Hinzuziehung einer Restauratorin, die innere Struktur ausgewählter an¬ tiker Baudenkmäler zerstörungsfrei zu untersuchen. Das Ziel der zerstörungsfreien Strukturaufklärung zum inneren Aufbau der Bauteile war es, einerseits sicherheitsrelevante Informationen für die statische Nachweisführung bereitzustellen, sowie andererseits eine Planungsgrundlage für die eventuell erforder¬ liche Ertüchtigung der Baudenkmäler zu schaffen. Im Fokus der Untersuchungen standen dabei das Markttor von Milet und das Säulenjoch der Heiligen Halle am Markt von Priene1 • Im nachstehenden Beitrag werden exemplarisch die am Markttor von Milet durchgeführten Untersuchungen vorgestellt.
T2 - Workshop Kulturguterhaltung - Vom Dampfkessel zu Nanomaterialien
CY - Berlin, Germany
DA - 17.11.2021
KW - Bauzustandsanalyse
KW - Radar
KW - Radiografie
PY - 2021
SN - 2567-1251
VL - 3
SP - 47
EP - 57
PB - Druckerei G. Bohm
CY - Berlin
AN - OPUS4-54460
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
A1 - Fladt, Matthias
A1 - Wieland, M.
T1 - Internal water-repellent treatment - a novel strategy for mitigating alkali-aggregate reaction in concrete pavements
N2 - To prevent future alkali-aggregate reaction (AAR) damage, which has occurred frequently in the Germanhighway network in recent years, a new regulation has been drafted. This regulation severely limits the use of alkali-sensitive aggregates by requiring that their suitability be verified by certified inspectors using newly developed AAR concrete tests that involve the external supply of alkali. This has led to a significant limitation in the number of aggregates usable for concrete pavements. A novel AAR avoidance strategy is now being pursued, which aims to enable the use of borderline alkali-sensitive aggregates through the application of an internal water-repellent treatment. The addition of water repellents during concrete production should significantly reduce the ingress of water and external de-icing salts into the concrete pavement, thus reducing the potential for AAR damage.
This paper presents the results of laboratory tests to assess the suitability of this new AAR prevention strategy. Representative, highly AAR-susceptible road paving concrete made with an alkali- sensitive greywacke and various water repellents were used as the basis for these experiments. The tests for concrete suitability included determining the conventional fresh and hardened concrete properties as well as concrete prism tests with external alkaline supply. Building on these results, laser-induced breakdown spectroscopy (LIBS) analyses of de-icing-salt intrusion as well as microscopic examinations for verification of the AAR characteristics were carried out.
The results of the AAR concrete tests with external alkaline supply support the conclusion that, when hydrophobic agents containing a suitable active ingredient are used, the AAR damage process in road paving concrete can be sufficiently prevented.
T2 - 16th International Conference on Alkali-Aggregate Reaction in Concrete
CY - Lisboa, Portugal
DA - 31.05.2022
KW - Concrete pavements
KW - Internal water-repellent treatment
KW - Preventive measures
KW - Testing for potential AAR
PY - 2021
SN - 978-972-49-2315-4
VL - 1
SP - 511
EP - 524
AN - OPUS4-54551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kositz, M.
A1 - Hünger, K.-J.
A1 - Weise, Frank
T1 - Regression analysis of ASR expansions and silica dissolution in the presence of NaCl
N2 - The durability of concrete structures due to alkali-silica-reaction (ASR) is usually been assessed by ASR concrete prism tests (CPT). Therefore, the expansion of concrete specimens indicates an alkalisensitivity.
In Germany these tests are performed at 40°C or accelerated 60°C. Nevertheless, ASR prism tests are expensive, power and time-consuming. For these reasons, an alternative chemical test (“mod. BTU-test”) was developed in the past. The “mod. BTU-test” was correlated with German standard CPT.
In this test, the solubility of silica and alumina in the liquid phase is measured by ICP-OES.
For special requirements in concrete road construction, stricter test procedures are necessary. The specimens are repeatedly subjected to cyclic alternating storage in NaCl. On the one hand, the presence of NaCl increases the ASR expansion, on the other hand NaCl also changes the dissolution behaviour of silica and alumina.
For now is not possible to correlate the solubilities of “mod. BTU-test” and ASR expansions influenced by NaCl. Therefore, four aggregates with different ASR sensitivities were chosen and ASR concrete prism tests (in addition with NaCl) have been performed. According to the “mod. BTU-test” the solubilities of silica and alumina in presence of different NaCl concentrations were measured.
This paper is about the regression analysis of silica and alumina dissolution and ASR expansion tests in presence of NaCl. The regression analysis shows the influence of a quasi-continuous and an interrupted cyclic alternating storage. Additionally the effects of temperature and NaCl concentration are investigated. In the end, a suitable NaCl concentration of the “mod. BTU-test” for dissolution experiments is recommended. The “mod. BTU-Test” with NaCl might be a serious and reliable test method for ASR classification for concrete road construction.
T2 - 16th International Conference on Alkali-Aggregate Reaction in Concrete
CY - Lisboa, Portugal
DA - 31.05.2022
KW - Alkali silica reaction
KW - Alkaline solution
KW - Alumina & silica dissolution
KW - NaCl
KW - Regression analysis
PY - 2021
SN - 978-972-49-2315-4
VL - 1
SP - 711
EP - 723
AN - OPUS4-54552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krütt, Enno
A1 - Pirskawetz, Stephan
A1 - Wallau, Wilma
A1 - Meng, Birgit
T1 - Development of an automated 60 °C Concrete Prism Test
N2 - ln most of the ASR-test procedures, the expansion of concrete or mortar specimens is used as an indicator to assess the ASR-potential of an aggregate or a specific concrete mix. For these tests, the specimens are stored in an ASR-provoking environment, where the reaction is accelerated by elevated temperature and humidity. To measure the length change, the storage must be interrupted for at least a few minutes. Düring the 60 °C Concrete Prism Test (60 °C-CPT), the specimens are cooled down to 20 °C for 24 hours, to ensure the same hygrothermal conditions for every measurement. This limits the number of measurements during the test period and may lead to additional effects, that probably influence the expansion development.
With a recently developed device, it is possible to continuously monitor the expansion ofprisms without interrupting the ASR-provoking storage. Due to the dense database of this automated test, the results can contribute to a better understanding of the ASR-process. This study compares results of the automated and conventional 60 °C-CPT. Tests of different aggregates showed, that the results of the automated and conventional test are consistent, but the expansions during the conventional test are generally higher. Preliminary results led to the conclusion, that the cooling for the measurements leads to additional expansions. Therefore, a modified threshold should be discussed for the automated 60 °C-CPT.
T2 - 16th International Conference on Alkali-Aggregate Reaction in Concrete
CY - Lisboa, Portugal
DA - 31.05.2022
KW - 60 °C-CPT
KW - ASR expansion monitoring
KW - Automated testing
PY - 2021
SN - 978-972-49-2315-4
VL - 1
SP - 789
EP - 799
AN - OPUS4-54553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fladt, Matthias
T1 - Utilisation of alkali-sensitive aggregates for concrete pavements by internal hydrophobisation
N2 - In order to avoid the increased ASR damage to concrete pavements in the German motorway network in the future, the ARS 04/2013 introduced mandatory suitability tests to exclude alkali-sensitive aggregates in new construction measures. This resulted in a significant reduction of suitable aggregates. Against this background, borderline alkali-sensitive aggregates are to be made usable by adding an internal water repellent agent during concrete casting. The ASR avoidance strategy is based on the significant reduction of the penetration of water and de-icing salt solution into the concrete pavement. Laboratory tests show that, with a suitable active ingredient, the ASR damage process can be significantly reduced with internal hydrophobisation. The disadvantage is that this is associated with a deterioration of the mechanical properties and the resistance to freeze-thaw with de-icing salt. The aim of the ongoing research is to reduce these disadvantages through targeted modification of the hydrophobising agent and air-entraining agent.
T2 - European Coatings Show
CY - Online meeting
DA - 13.09.2021
KW - Concrete pavement
KW - Alkali-Silica-Reaction
KW - Hydrophobisation
KW - Preventive measure
PY - 2021
AN - OPUS4-54549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
T1 - Begutachtung Berliner Tuffsteinfassaden - Turmruine der Kaiser-Wilhelm-Gedächtniskirche und Charlottenburger Tor
N2 - Am Ende des 19. und zu Beginn des 20. Jahrhunderts wurden auch in Berlin vermehrt Fassadenverblendung aus Eifeler Tuffsteinen errichtet. Die Eifeler Tuffsteine zeichnen sich aufgrund ihrer hohen Porosität einerseits durch eine gute Verarbeitbarkeit aus. Andererseits sind sie nur schwach gebunden und besitzen deshalb eine geringe Verwitterungsbeständigkeit.
T2 - Workshop zur Kulturguterhaltung
CY - Berlin, Germany
DA - 17.11.2021
KW - Fassade
KW - Tuffstein
KW - Schalenbildung
PY - 2021
AN - OPUS4-54633
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Plattform MaterialDigital (PMD): Konsortium, Zielsetzung, Core Ontology
N2 - Die Materialwissenschaft und Werkstofftechnik (MSE) durchläuft derzeit eine digitale Transformation, die ein strukturiertes und interoperables Datenmanagement erfordert. Die Plattform MaterialDigital (PMD) adressiert diese Herausforderungen mit der PMD Core Ontology (PMDco), die inzwischen in Version 3.0 vorliegt. Diese mittlere Ontologieebene schafft eine Brücke zwischen abstrakten Top-Level-Ontologien wie der ISO/IEC 21838-2 standardisierten Basic Formal Ontology (BFO) und spezifischen domänenspezifischen Vokabularen. Ziel ist die Förderung semantischer Interoperabilität sowie die Nachvollziehbarkeit und Wiederverwendbarkeit von Daten entlang der gesamten Wertschöpfungskette in der MSE.
Die Präsentation gibt einen Überblick über die Zielsetzung des PMD-Konsortiums, die Community-getriebene Entwicklung der PMDco sowie ihre Rolle in digitalen Workflows und Demonstratoren. Praxisbeispiele beinhalten die semantische Modellierung von Zugversuchen gemäß ISO 6892-1:2019-11 mithilfe der darauf aufbauenden Zugversuch-Ontologie (TTO) sowie die Umwandlung experimenteller Daten von Studierenden in maschinenlesbare Wissensgraphen über eine elektronische Laborbuch-Pipeline. Zudem wird die Ontologieentwicklung durch NLP-gestützte Ansätze (z. B. für Mikroskopie) sowie die Harmonisierung heterogener Datenquellen (z. B. im Orowan-Demonstrator) vorgestellt. Damit leistet PMDco einen entscheidenden Beitrag zur digitalen Zukunft der Materialforschung.
T2 - Abschlusskolloquium LeBeDigital
CY - Berlin, Germany
DA - 04.06.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalisierung
KW - Digitale Transformation
KW - Plattform MaterialDigital
PY - 2025
AN - OPUS4-63295
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tamsen, Erik
T1 - Towards an automatic optimization framework for performance oriented precast concrete design
N2 - Concrete has a long history in the construction industry and is currently one of the most widely used building materials. Especially precast concrete elements are frequently utilized in construction projects for standardized applications, increasing the quality of the composite material, as well as reducing the required building time. Despite the accumulated knowledge, continuous research and development in this field is essential due to the complexity of the composite combined with the ever-growing number of applications and requirements. Especially in view of global climate change, design aspects as CO2 emissions and resource efficiency require new mix designs and optimization strategies. A result of the material’s high complexity and heterogeneity on multiple scales is that utilizing the full potential with changing demands is highly challenging, even for the established industry. We propose a framework based on an ontology, which automatically combines experimental data with numerical simulations. This not only simplifies experimental knowledge transfer, but allows the model calibration and the resulting simulation predictions to be reproducible and interpretable. This research shows a way towards a more performance oriented material design. Within this talk we present our workflow for an automated simulation of a precast element, demonstrating the interaction of the ontology and the finite element simulation. We show the automatic calibration of our early-age concrete model [1, 2], to improve the prediction of the optimal time for the removal of the form work.
T2 - The 8th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS) 2022
CY - Oslo, Norway
DA - 05.06.2022
KW - Performance oriented concrete design
KW - Early-age concrete
KW - Precast concrete
KW - Ontology
KW - Optimization workflow
PY - 2022
AN - OPUS4-55302
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tamsen, Erik
T1 - Towards an automatic optimization framework for performance oriented precast concrete design
N2 - The aim of the project LeBeDigital is to present opportunities of digitalization for concrete applications and show a way towards a performance oriented material design.
Due to the high complexity of the manufacturing process of concrete and the range of parameters affecting the effective composite properties, a global optimization is challenging.
Currently, most optimization is only carried out on a narrow scope related to the respective players, e.g. a mix optimization for a target strength, or a design optimization for minimum weight, using a given mix. To enable a path toward a full global optimization
requires a reproducible chain of data, accessible for all contributors.
We propose a framework based on an ontology, which automatically combines experimental data with numerical simulations. This not only simplifies experimental knowledge transfer, but allows the model calibration and the resulting simulation predictions to be
reproducible and interpretable. In addition to an optimized set of parameters, this setup allows to study the quality and uncertainty of the data and models, as well as giving information about optimal experiments to improve the data set.
We will present the proposed optimization workflow, using the example of a precast concrete element. The contribution will focus on the workflow and challenges of an interoperable FEM formulation.
T2 - Material Science and Engineering, MSE Congress 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Performance oriented concrete design
KW - Ontology
KW - Optimization workflow
PY - 2022
AN - OPUS4-56208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koch, Claudia
T1 - Marktüberwachung und Digitalisierung der Qualitätsinfrastruktur: Initiative QI-Digital
N2 - Der Vortrag gibt einen Überblick zur Digitalisierung der Qualitätsinfrastruktur sowie den Aktivitäten der Initiative QI-Digital, in der die BAM engagiert ist um Lösungen für eine moderne QI zu entwickeln, erproben und die Anwendung zu bringen. Besonderes Augenmerk liegt auf der Bedeutung und Nutzbarmachung für die Marktüberwachung.
T2 - Deutsche Marktüberwachungskonferenz 2024
CY - Berlin, Germany
DA - 27.11.2024
KW - Qualitätsinfrastruktur
KW - Marktüberwachung
KW - Digitalisierung
KW - Digitale Transformation
PY - 2024
AN - OPUS4-62056
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Birgit
T1 - Betondesign digital - Potenziale für das Bauwesen
N2 - Beton ist weltweit einer der wichtigsten Konstruktionswerkstoffe und zeichnet sich durch eine enorme Anpassungsfähigkeit an sich verändernde Anforderungen aus. Damit verbunden ist eine hohe und kontinuierlich zunehmende Komplexität hinsichtlich der Ausgangsstoffe, Rezepturen und des Herstellungsprozesses. Folglich setzt eine Ausschöpfung des technischen und umweltbezogenen Potenzials der Betonbauweise höchste Expertise bei den Einzelakteuren der Bauindustrie voraus.
T2 - MatFo2022 „Vom Material zur Innovation: Digital, Neutral, Vital“
CY - Cologne, Germany
DA - 14.11.2022
KW - Beton
KW - Zement
KW - Digitalisierung
KW - Ontologien
PY - 2022
UR - https://www.werkstofftechnologien.de/veranstaltungen/matfo2022-vom-material-zur-innovation-digital-neutral-vital
AN - OPUS4-59140
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Andrés Arcones, Daniel
A1 - Diercks, Philipp
A1 - Robens-Radermacher, Annika
A1 - Rosenbusch, Sjard Mathis
A1 - Tamsen, Erik
A1 - Tyagi, Divyansh
A1 - Unger, Jörg F.
T1 - FenicsXConcrete
N2 - FenicsXConcrete is a Python package for the simulation of mechanical problems. The general PDE solving software FEniCSx is extended with classes describing experimental setups, mechanical problems, thermo-mechanical problems, additive manufacturing and sensors.
KW - FEM
KW - Fenics
KW - Concrete modelling
PY - 2023
UR - https://github.com/BAMresearch/FenicsXConcrete
DO - https://doi.org/10.5281/zenodo.7780757
PB - Zenodo
CY - Geneva
AN - OPUS4-59121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Diercks, Philipp
A1 - Veroy, K.
A1 - Robens-Radermacher, Annika
A1 - Unger, Jörg F.
T1 - Multiscale modeling of linear elastic heterogeneous structures via localized model order reduction
N2 - In this paper, a methodology for fine scale modeling of large scale linear elastic structures is proposed, which combines the variational multiscale method, domain decomposition and model order reduction. The influence of the fine scale on the coarse scale is modelled by the use of an additive split of the displacement field, addressing applications without a clear scale separation. Local reduced spaces are constructed bysolving an oversampling problem with random boundary conditions. Herein, we inform the boundary conditions by a global reduced problem and compare our approach using physically meaningful correlated samples with existing approaches using uncorrelated samples. The local spaces are designed such that the local contribution of each subdomain can be coupled in a conforming way, which also preserves the sparsity pattern of standard finite element assembly procedures. Several numerical experiments show the accuracy and efficiency of the method, as well as its potential to reduce the size of the local spaces and the number of training samples compared to the uncorrelated sampling
KW - Multiscale methods
KW - Variational multiscale method
KW - Localized model order reduction
KW - Proper orthogonal
PY - 2024
UR - https://arxiv.org/abs/2201.10374
DO - https://doi.org/10.48550/arXiv.2201.10374
PB - Arxiv; Cornell Tech
CY - New York, NY
AN - OPUS4-59803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kjaervik, Marit
A1 - Schwibbert, Karin
A1 - Dietrich, P.M.
A1 - Unger, Wolfgang
T1 - NAP-XPS spectra of the bacterial cell-envelope of Pseudomonas fluorescens bacteria
N2 - Pseudomonas fluorescens (Gram-negative) bacteria purchased from Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures were analyzed using high-resolution x-ray photoelectron spectroscopy at near ambient pressure conditions (NAP-XPS), 1500 Pa water vapor atmosphere. Fresh layers of P. fluorescence bacteria were grown on Luria Broth agar plates. Bacteria were taken from the agar plate with a sterile spatula and gently spread on a Si-wafer piece for NAP-XPS analysis. The NAP-XPS spectra of the bacterial envelope of P. fluorescence were obtained using monochromatic Al Kα radiation and include a survey scan and high-resolution spectra of C 1s, N 1s, P 2p, and O 1s as well. The presentation of the C 1s high-resolution spectrum includes the results of peak fitting analysis.
KW - Pseudomonas fluorescens
KW - Cell-envelope
KW - Water atmosphere
KW - Near ambient x-ray photoelectron spectroscopy
KW - NAP-XPS
PY - 2022
DO - https://doi.org/10.1116/6.0001543
SN - 1055-5269
VL - 29
IS - 1
SP - 014008-1
PB - AVS
AN - OPUS4-54464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Anja
T1 - Reducing Escherichia coli adhesion to PET by modulating spatial periods of laser-induced surface nanoripples
N2 - Using nanofiber-like cell appendages, secreted proteins and sugars, bacteria can establish initial surface contact followed by irreversible adhesion and the formation of multicellular biofilms. Here, the stabilizing extracellular biofilm matrix together with physiological changes on the single cell level leads to an increased resilience towards harsh environmental conditions, antimicrobials, the host immune response and established cleaning procedures. Persistent microbial adhesion on e.g., medical implants, in water supply networks or food-processing industry is often associated with chronic inflammation, nosocomial and foodborne infections, enhanced biofouling and product contamination. To prevent persistent microbial colonization, antibacterial surface strategies often target the initial steps of biofilm formation and impede adhesion of single cells before a mature biofilm is being formed. While chemical coatings have been widely used, their restricted biocompatibility for eukaryotic cells and attenuated antibacterial-effects due to compound release limit their areas of application and alternative strategies focus on modified surfaces topographies to impede bacterial adhesion. In this work, we used ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns) to generate laser-induced periodic surface structures (LIPSS) with different submicrometric periods ranging from ~210 to ~610 nm on commercial poly(ethylene terephthalate) (PET) foils. Following structurally and chemically analyses, PET samples were subjected to bacterial colonization studies with Escherichia coli TG1, a bacterial test strain with a strong biofilm formation capacity due to the formation of nanofiber-like cell-appendages (pili). Bacterial adhesion tests revealed that E. coli repellence decisively depends on the spatial periods of the LIPSS with the strongest reduction (~91%) in cell adhesion observed for LIPSS periods of 214 nm. Scanning electron microscopy and additional biofilm studies using a pili-deficient E. coli TG1 strain revealed the importance of extracellular appendages in the bacterial repellence observed here, thus, pointing out new antibiotics-free strategies for antibacterial surfaces by impeding nanofiber-mediated bacterial adhesion.
T2 - E-MRS Spring Meeting 2022
CY - Online meeting
DA - 30.05.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Bacterial adhesion tests
KW - Bacteria repellent surfaces
KW - Polymer foils
KW - E. coli
PY - 2022
AN - OPUS4-54930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
A1 - Bilgin, S.
A1 - Hoppe, Johannes
A1 - Fontana, P.
A1 - Meng, Birgit
ED - Middendorf, B.
ED - Fehling, E.
ED - Wetzel, A.
T1 - Composite UHPC facade elements with self-cleaning surface: Aspects of technological manufacturing
N2 - In the framework of the European collaborative project H-House, which was finished in 2017, large façade elements were developed consisting of a box shaped external shell of ultra-high-performance concrete (UHPC) with a functionalized surface and an insulation of autoclaved aerated concrete (AAC). The exposed concrete of the elements was further refined by adding self-cleaning properties to the surface through imprinting a microstructure in combination with chemical agents directly in the casting process. The paper focuses on selected technological aspects of the manufacturing process of large-scale prototypes. Presented are results of the upscaling process of functionalized surfaces from small specimen up to large UHPC composite facade elements produced for the construction of a demonstrator.
T2 - 5th International Symposium on Ultra-High Performance Concrete and High Performance Construction Materials (HiPerMat 2020)
CY - Kassel, Germany
DA - 11.03.2020
KW - Ultra-High Performance Concrete
KW - Facade Elements
KW - Self-Cleaning Properties
KW - Architectural Concrete
PY - 2020
SN - 978-3-7376-0828-2
DO - https://doi.org/10.17170/kobra-202002271026
IS - 32
SP - 51
EP - 52
PB - kassel university press
CY - Kassel
AN - OPUS4-51908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
T1 - Composite UHPC facade elements with self-cleaning surface: Aspects of technological manufacturing
N2 - In the framework of the European collaborative project H-House, which was finished in 2017, large façade elements were developed consisting of a box shaped external shell of ultra-high-performance concrete (UHPC) with a functionalized surface and an insulation of autoclaved aerated concrete (AAC). The exposed concrete of the elements was further refined by adding self-cleaning properties to the surface through imprinting a microstructure in combination with chemical agents directly in the casting process. The paper focuses on selected technological aspects of the manufacturing process of large-scale prototypes. Presented are results of the upscaling process of functionalized surfaces from small specimen up to large UHPC composite facade elements produced for the construction of a demonstrator.
T2 - 5th International Symposium on Ultra-High Performance Concrete and High Performance Construction Materials (HiPerMat 2020)
CY - Kassel, Germany
DA - 11.03.2020
KW - Ultra-High Performance Concrete
KW - Facade Elements
KW - Self-Cleaning Properties
KW - Architectural Concrete
PY - 2020
AN - OPUS4-51912
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Buchheim, Janine
T1 - A new approach towards performance-related design and scientific evaluation of joint sealing systems
N2 - While there is a permanent improvement of concrete pavement mixtures and pavement construction types over the last decades, the state-of-the-art joint sealing materials and joint constructions seem to stagnate on an antiquated empirical level. This status has been reaffirmed in the latest European standard.
The consequences in the motorway network due to unsatisfying capability and durability of joint sealing systems are unacceptable. In addition, inadequate traffic performance (noise emissions, roll-over comfort) and traffic safety losses in the joint area of concrete pavements are existing challenges. These deficits and weaknesses reflect a demand for joint sealing materials and constructions whose approval requirements take functional aspects into account. Furthermore a sufficient analysis of decisive loads and a practice-oriented method to evaluate the requirements towards performance and durability is still missed.
In this contribution decisive loads to German highways are analyzed. The design of test specimen for representative functional testing of joint sealing systems is discussed. The focus is on the geometry of the test specimens and the used concrete mixture. Finally, a new approach for a function-orientated test concept that considers representative load functions is presented. The potential of this approach to validate the durability and capability of various joint sealing systems is also presented using an example.
T2 - RILEM International Symposium on Bituminous Materials
CY - Online Meeting
DA - 14.12.2020
KW - Joint sealing
KW - Expansion joint
KW - Performance testing
KW - Capability
KW - Durability
PY - 2020
AN - OPUS4-52437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigel, Sandra
A1 - Recknagel, Christoph
T1 - FTIR-Charakterisierung von Bitumen - Möglichkeiten und Chancen
N2 - Das erdölstammige Bindemittel Bitumen weist eine so komplexe Struktur auf, dass diese mit den derzeit eingesetzten Verfahren nur eingeschränkt erfasst werden kann. Eine innovative und vielversprechende Möglichkeit bietet in diesem Zusammenhang die FTIR-Spektroskopie in Kombination mit einer chemometrischen Auswertung, mit der schnell und einfach Aussagen über die Zusammensetzung sowie verschiedenste physikalische und chemische Eigenschaften von bitumenhaltigen Materialien möglich werden.
KW - Bitumen
KW - FTIR
KW - Chemometrie
KW - Multivariate Analysemethoden
KW - Charakterisierung
KW - Identifizierung von Additiven
PY - 2021
SN - 1618-8357
SP - 42
EP - 49
PB - ALPHA Informationsgesellschaft mbH
CY - Lampertheim
AN - OPUS4-53486
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schwettmann, K.
T1 - Post carbon road - The endless cycle of bitumen reuse
N2 - In Germany, the reuse of asphalt has a long tradition. Since the 1980s, the reclaimed
asphalt has been recycled achieving a reuse rate of around 90% and thus a very high
value in the last years. In the future, instead of the amount, the quality of the
reclaimed asphalt will be more important because the recycled asphalt will be reused
again and again. Thus, these asphalt mixes are in the second or even third cycle of
reuse. Concerning this situation, the question arises if asphalt can be reused several
times without any loss in quality. An important factor affecting the asphalt quality is the
binder bitumen. During the production, construction and service life, the ageing of this
binder occurs causing a hardening of the bitumen. To compensate this hardening,
additives for the reclaimed asphalt in terms of rejuvenation agents (rejuvenators) gain
in importance. With these rejuvenators, the physical properties of bitumen can be
modified e.g. the hardness and the stiffness reduced. However, the mechanism of the
rejuvenation agents and the effects of the bitumen chemistry are largely unknown
because the composition of the products varies very strongly. But with growing
knowledge about these mechanisms and effects of the rejuvenation agents, the
chemical composition and thus the physical and ageing behavior of bitumen can be
targeted modified by the use of suitable rejuvenators. In this work, the actual results of
the project Postcarbone road should be presented including investigations about the
chemical and physical mechanisms as well as the efficiency of different rejuvenators.
Further, a model for the cyclic reuse of bitumen should be developed. Based on this
model, the choice of a suitable rejuvenation agent for the considered bitumen or rather
asphalt should be possible. The project Postcarbone road (392670763) is funded by the
German Research Foundation (DFG).
T2 - 7th Eurasphalt and Eurobitume Congress
CY - Online meeting
DA - 15.06.2021
KW - Bitumen
KW - Multiple ageing and rejuvenation
KW - Conventional testing
KW - DSR
KW - BBR
KW - FTIR
KW - Asphaltene content
KW - Column chromatography
PY - 2021
AN - OPUS4-53489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pelkner, Matthias
T1 - Simulation und Analyse des Einflusses der Prozesswärme in der additive Fertigung auf Leitfähigkeit und Wirbelstromsignale
N2 - Additive Fertigungstechnologien gewinnen zunehmend an Bedeutung. Insbesondere das Laser-Pulverbettschmelzen findet häufig Anwendung bei der Herstellung komplexer Funktionsbauteile oder kleiner Serien von Werkstücken. In sicherheitskritischen Bereichen, wie der Luft- und Raumfahrt, ist eine umfassende Qualitätskontrolle unverzichtbar. Traditionell werden hierfür nach der Fertigung zerstörungsfreie „Offline“-Prüfmethoden wie die Computertomographie eingesetzt. Um die Effizienz und Wirtschaftlichkeit zu erhöhen, wurden jedoch in jüngster Zeit Online-Prüfverfahren (in-situ) wie die Wirbelstromprüfung oder die optische Tomographie weiterentwickelt.
Bei der in-situ-Wirbelstromprüfung werden die zuletzt gefertigten Schichten überprüft. Aufgrund des durch den Fertigungsprozess eingebrachten Wärmeflusses ist die Oberfläche dieser Schichten deutlich stärker erhitzt als die Umgebungstemperatur im Bauraum. Diese Erwärmung führt zu einem Anstieg des spezifischen Widerstands, wodurch die erzeugten Wirbelströme in der Oberfläche schwächer werden, und die Signalstärke abnimmt. Eine Anpassung der Anregefrequenz kann jedoch dazu beitragen, diesen Effekt zu reduzieren.
Der vorliegende Beitrag untersucht die Auswirkungen unterschiedlicher Oberflächentemperaturen auf die Wirbelströme. Dafür wurden die von einer Sonde erzeugten Wirbelströme bei variierenden Oberflächentemperaturen – und damit bei unterschiedlichen Leitfähigkeitswerten – simuliert. Grundlage dieser Simulationen waren temperaturabhängige Leitfähigkeitswerte von additiv gefertigten Bauteilen aus dem Werkstoff 316L, die zuvor ermittelt wurden. Ziel dieser Untersuchungen ist die Entwicklung und Präsentation einer Strategie zur Anpassung der Wirbelstromprüfung während des Fertigungsprozesses.
T2 - DGZfP-Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - Wirbelstromprüfung
KW - Magnetosresistive Sensoren
KW - FEM-Simulationen
KW - Elektrische Leitfähigkeit
KW - Online-Prüfung
KW - Additive Fertigung
PY - 2025
AN - OPUS4-63283
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
A1 - Schwibbert, Karin
T1 - Laserstrukturierte Oberflächen: Ein Weg zur Kontrolle der Biofilmbildung?
N2 - Bakterielle Biofilme stellen in medizinischen und industriellen Bereichen ein ernsthaftes Problem dar. Eine der größten gesellschaftlichen Herausforderungen liegt in der zunehmenden Resistenz von Bakterien gegen Biozide, die bei antimikrobiellen Behandlungen eingesetzt werden, z.B. durch übermäßigen Einsatz in Medizin, Industrie und Landwirtschaft oder durch Reinigung und Desinfektion in Privathaushalten. Daher sind neue effiziente bakterienabweisende Strategien, die den Einsatz von Bioziden vermeiden, dringend erforderlich.
Ein vielversprechender Weg zur Erzielung bakterienabweisender Oberflächen liegt in der berührungslosen und aseptischen großflächigen Laserbearbeitung von technischen Oberflächen. Maßgeschneiderte Oberflächentexturen, ermöglicht durch verschiedene Laserbearbeitungsstrategien, die zu topographischen Skalen im Bereich von Nanometern bis Mikrometern führen, können eine Lösung für diese Herausforderung darstellen.
In dem Vortrag wird ein Überblick über den aktuellen Stand der Technik bei der subtraktiven Texturierung von Laseroberflächen zur Kontrolle der Biofilmbildung bei verschiedenen Bakterienstämmen und in unterschiedlichen Umgebungen gegeben. Auf der Grundlage spezifischer Eigenschaften von Bakterien und laserbearbeiteten Oberflächen werden die Herausforderungen antimikrobieller Oberflächendesigns erörtert und zukünftige Richtungen aufgezeigt.
T2 - GRAVOSeminar, GRAVOmer Kompetenznetzwerk
CY - Online meeting
DA - 28.02.2024
KW - Laser-Materialbearbeitung
KW - Ultrakurzpuls-Laser
KW - Biofilme
KW - Antibakterielle Oberflächen
KW - Oberflächenfunktionalisierung
PY - 2024
UR - https://gravomer.de/veranstaltungen-anzeigen/laserstrukturierte-oberflaechen-ein-weg-zur-kontrolle-der-biofilmbildung
AN - OPUS4-59594
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nietzke, Jonathan
A1 - Rhode, Michael
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
T1 - Experimental and numerical characterization of hydrogen diffusion in thick-walled submerged arc welded joint of S420G2+M offshore steel grade
N2 - Offshore wind turbines are an important goal in national energy strategies worldwide. Foundation structures are manufactured from submerged arc welded (SAW) plates with thicknesses up to 200 mm. In that connection, high-strength steels like the S420G2+M are more and more applied offering the possibility for increased stability and load-bearing capacity of the foundations. These offshore steel grades can show a susceptibility for delayed hydrogen assisted cold cracking of the weld joints. For that purpose, a minimum waiting time (MWT) of up to 48 h (dependent on applied standards) is recommended before non-destructive testing is allowed and conducted. But this concept is based on older steel grades that have been used for three or more decades. Nowadays, the metallurgical improvements (clean steels, proper rolling, and heat treatment) of base materials and well as welding consumables must be anticipated. Hence, the MWT concept should be critically discussed as it is assumed to be very conservative. For that reason, the focus of this study was to investigate the diffusion behavior in S420G2+M steel and its multi-layer SAW joint. Electrochemical permeation experiments were carried at room temperature. Boundary conditions were anticipated in terms of using different sample thicknesses. From the experimental data, hydrogen diffusion coefficients and absorbed diffusible hydrogen concentrations had been calculated. It was shown that hydrogen diffusion in the base material is increased compared to the weld metal. In addition, the sample thickness had a significant on the calculated diffusion coefficients. The minimum and maximum diffusion coefficients had been used for numerical modelling of the hydrogen diffusion in the welding joint. It became clear that a MWT must be always regarded together with a critical initial diffusible hydrogen concentration for the evaluation of a possible delayed cracking as diffusion times were mostly > 48 h due to the thick plates.
T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022
CY - Ghent, Belgium
DA - 11.10.2022
KW - Hydrogen
KW - Submerged arc welding
KW - Diffusion
KW - Minimum waiting time
KW - Electrochemical permeation
PY - 2022
SP - 1
EP - 11
CY - Ghent, Belgium
AN - OPUS4-56075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Czeskleba, Denis
A1 - Kannengießer, Thomas
T1 - Untersuchung von Spannungsrelaxationsrissmechanismen mittels Simulation einachsiger Spannungszustände in der Grobkornzone von UP-geschweißtem CrMoV-Stahl
N2 - Druckbehälter mit großen Wandstärken (250+ mm) aus hochwarmfesten, niedriglegierten Stählen werden hauptsächlich Mehrdraht-Unterpulver-(UP) geschweißt. Der damit verbundene hohe Energieeintrag führt unter anderem zu hohen lokalen Schweißeigenspannungen, welche bei unsachgemäßer Prozessführung der notwendigen Wärmenachbehandlung (PWHT) zu Spannungsrelaxationsrissen (SRR) führen. In den Bewertungskriterien zur Spannungsrelaxationsrissanfälligkeit finden weder die, mit klassischen, freischrumpfenden Schweißversuchen nicht abbildbaren, erhöhten Eigenspannungen aus der Schrumpfbehinderung der Bauteilsteifigkeit Beachtung, noch die damit einhergehenden metallurgischen Effekte wie bspw. das Ausscheidungswachstum während der PWHT und damit einhergehende Härteunterschiede an den Korngrenzen bzw. die vorzeitige Alterung durch Bildung differenter Sonderkarbide. Die Aufheizrate des PWHT als Einflussfaktor für die SRR-Bildung bleibt derzeit ebenfalls unbeachtet.
Daher wurde eine Versuchsmethodik entwickelt, die eine mögliche SRR-Anfälligkeit durch die Kopplung von thermischer und mechanischer Beanspruchung untersucht. Dazu wurden Proben mit unterschiedlichen Gefügen thermisch simuliert und während des PHWT repräsentativ mit sehr hohen Lasten/Eigenspannungen mechanisch beansprucht.
Dazu wurde an Kleinzugproben für das as-welded UP-Schweißgut und die thermisch simulierte GKZ eines 13CrMoV9-10 die Dehnung des Prüfbereichs bei variablen Querspannungen und Aufheizraten gemessen. Diese aufheizraten- und gefügeabhängige Längenänderung der Probe wurde durch mathematische Prozeduren analysiert. Damit war es möglich, singuläre werkstoffliche Effekte auf μm-Ebene (Ausscheidungswachstum) als summarische Längen- bzw. Volumenänderung per klassischer Kurvendiskussion zu beschreiben. Die erste und zweite Ableitung zeigten eine ausscheidungsabhängige Härtezunahme, welche von der Spannung und Aufheizrate im geringen Maß linear abhängig war. Gleichzeitig sind Volumenänderungen bei Bildung und Wachstum differenter Sonderkarbide bekannt, welche zusammen mit gefügespezifischen Untersuchungen und der neuen Versuchsmethodik zu einer verbesserten Beurteilung der SRR-Anfälligkeit von geschweißten CrMoV-Stählen beitragen sollen. Prinzipiell ist die vorgestellte Methodik jedoch werkstoff- und zustandsoffen, d.h. sowohl für Grundwerkstoff e als auch definierte Wärmebehandlungsbedingungen geeignet. Dies ermöglicht erstmals die Schaffung einer Transfergröße zwischen Labor und realen Schweißungen, unter Beibehaltung der Bauteilsteifigkeit, d.h. vereinfachte, aber realistische Eigenspannungsabbildung als Grundlage für weitergehende gefügespezifische metallurgische Effekte während des PWHT.
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - UP-Schweißen
KW - Spannungsrelaxationsriss
KW - Wärmenachbehandlung
KW - Ersatzgeometrie
KW - Prüfverfahren
PY - 2022
SN - 978-3-96144-190-7
VL - 382
SP - 69
EP - 75
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-55946
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bodechtel, S.
A1 - Fuhrmann, A.
A1 - Henning, A.
A1 - Hahn, Oliver
A1 - Rabin, Ira
A1 - Kreische, W.
A1 - Mäder, M.
T1 - The Madonna with the Wash-Basin by Giulio Romano: A Multidisciplinary Study of the Painting’s History
N2 - In an interdisciplinary collaboration, restorers, art historians, and scientists examined Guilio Romano’s The Madonna with the Wash-Basin of 1525 (Dresden State Art Collections). Insights into the painting technique along with art historical comparisons provided the opportunity for a better understanding of the painting’s genesis, in particular concerning an early reworking of the background by the artist. A recovery and reconstruction of the earlier version of the background is now possible. The discovery of zinc in distinct passages of the painting, as well as the grey-black pigment stibnite and glass particles used as a supplement in paint layers are of special interest. The technological investigation initiated a discussion about the circumstances of the revision, as well as the painting’s relation to Vasari’s Lives of Artists.
KW - Giulio Romano
KW - Holy Family
KW - Basin
KW - Reworking
KW - Pentimenti
KW - Portrayal of St Joseph
KW - Sixteenth-century painting technique
KW - Raphael school
KW - Zinc
KW - Antimony black (stibnite)
KW - Vasari
PY - 2022
DO - https://doi.org/10.1080/00393630.2022.2118302
VL - 2022
SP - 2
EP - 12
PB - Routledge Taylor & Francis Group
CY - London, UK
AN - OPUS4-55970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Czeskleba, Denis
T1 - Entwicklung von Wärmenachbehandlungskonzepten zur Vermeidung von Spannungsrelaxationsrissen - Endbericht (DVS-Nr. 01.2261, IGF-Nr. 20171 N)
N2 - Komponenten aus dickwandigen, hochwarmfesten CrMoV-Stählen erfordern eine anspruchsvolle UP-Schweißverarbeitung. Dabei muss die notwendige Wärmenachbehandlung der Schweißnaht (PWHT) sicher beherrscht werden. Hier kann u.U. Bauteilversagen infolge von Spannungsrelaxationsrissbildung (SRR) auftreten. Bislang erfolgt die Beurteilung der SRR-Neigung primär über Ersatzgrößen, wie temperaturbedingte Änderung der Härte und Duktilität.
Die Wirkung der konstruktiven Schrumpfbehinderung einer Schweißnaht auf die SRR ist bislang völlig unbekannt.
Hier setzt das Forschungsprojekt an, hinsichtlich der Gewinnung und Optimierung der Parameter für die PWHT unter realitätsnahen Bauteilsteifigkeiten (definierte Einspannbedingung) mit dem Ziel der SRR-Vermeidung. Am Beispiel des niedriglegierten, hochwarmfesten Stahls 13CrMoV9-10 wurden UP-Schweißungen unter industriepraktischen
Bedingungen freischrumpfend bzw. unter definierter Schrumpfbehinderung durchgeführt. Diese wurden mit unterschiedlichen PWHT-Szenarien (Variation der Aufheizrate und Endtemperatur) beaufschlagt. Die Ergebnisse des Projektes DVS 01.2261 / IGF 20171 N werden in diesem Beitrag vorgestellt.
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - UP-Schweißen
KW - Spannungsrelaxationsriss
KW - Forschung
KW - Wärmenachbehandlung
PY - 2022
AN - OPUS4-55945
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Czeskleba, Denis
T1 - Untersuchung von Spannungsrelaxationsrissmechanismen mittels Simulation einachsiger Spannungszustände in der Grobkornzone von UP geschweißtem CrMoV Stahl
N2 - Druckbehälter mit großen Wandstärken (250+ mm) aus hochwarmfesten, niedriglegierten Stählen werden hauptsächlich Mehrdraht-Unterpulver-(UP) geschweißt. Der damit verbundene hohe Energieeintrag führt unter anderem zu hohen lokalen Schweißeigenspannungen, welche bei unsachgemäßer Prozessführung der notwendigen Wärmenachbehandlung (PWHT) zu Spannungsrelaxationsrissen (SRR) führen. In den Bewertungskriterien zur SRR-Anfälligkeit finden weder die, mit klassischen, freischrumpfenden Schweißversuchen nicht abbildbaren, erhöhten Eigenspannungen aus der Schrumpfbehinderung der Bauteilsteifigkeit Beachtung, noch damit einhergehende metallurgischen Effekte.
Die Aufheizrate des PWHT als Einflussfaktor für die SRR-Bildung bleibt blieb bisher unbeachtet. Daher wurde eine Versuchsmethodik entwickelt, die eine mögliche SRR-Anfälligkeit durch die Kopplung von thermischer und mechanischer Beanspruchung untersucht. Dazu wurden Proben mit unterschiedlichen Gefügen thermisch simuliert und während des PHWT repräsentativ mit sehr hohen Lasten/Eigenspannungen mechanisch beansprucht. Dazu wurde das as-welded UP-Schweißgut und die thermisch simulierte GKZ eines 13CrMoV9-10 Stahls untersucht und an Kleinzugproben, die Dehnung bei variablen Querspannungen und Aufheizraten gemessen.
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - UP-Schweißen
KW - Spannungsrelaxationsriss
KW - Wärmenachbehandlung
KW - Prüfverfahren
KW - CrMoV-Stahl
PY - 2022
AN - OPUS4-55947
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nietzke, Jonathan
A1 - Konert, Florian
T1 - Experimental and numerical characterization of hydrogen diffusion in thick-walled submerged arc welded joint of S420G2+M offshore steel grade
N2 - Offshore wind turbines are an important goal in national energy strategies worldwide. Foundation structures are manufactured from submerged arc welded (SAW) plates with thicknesses up to 200 mm. In that connection, high-strength steels like the S420G2+M are more and more applied offering the possibility for increased stability and load-bearing capacity of the foundations. These offshore steel grades can show a susceptibility for delayed hydrogen assisted cold cracking of the weld joints. For that purpose, a minimum waiting time (MWT) of up to 48 h (dependent on applied standards) is recommended before non-destructive testing is allowed and conducted. But this concept is based on older steel grades that have been used for three or more decades. Nowadays, the metallurgical improvements (clean steels, proper rolling, and heat treatment) of base materials and well as welding consumables must be anticipated. Hence, the MWT concept should be critically discussed as it is assumed to be very conservative. For that reason, the focus of this study was to investigate the diffusion behavior in S420G2+M steel and its multi-layer SAW joint. Electrochemical permeation experiments were carried at room temperature. Boundary conditions were anticipated in terms of using different sample thicknesses. From the experimental data, hydrogen diffusion coefficients and absorbed diffusible hydrogen concentrations had been calculated. It was shown that hydrogen diffusion in the base material is increased compared to the weld metal. In addition, the sample thickness had a significant on the calculated diffusion coefficients. The minimum and maximum diffusion coefficients had been used for numerical modelling of the hydrogen diffusion in the welding joint. It became clear that a MWT must be always regarded together with a critical initial diffusible hydrogen concentration for the evaluation of a possible delayed cracking as diffusion times were mostly > 48 h due to the thick plates.
T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022
CY - Ghent, Belgium
DA - 11.10.2022
KW - Hydrogen
KW - Submerged arc welding
KW - Minimum Waiting Time
KW - Cold Cracking
KW - Offshore steel grade
PY - 2022
AN - OPUS4-56008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Repair welding of pressurized in-service hydrogen pipelines - A review on current challenges and strategies
N2 - As energy carrier of the future, green hydrogen can make a decisive contribution to a sustainable energy supply. Particularly important is the decarbonization of heavy industry. Therefore, a reliable supply of hydrogen must be guaranteed. A hydrogen pipeline grid can achieve this purpose. In Europe concrete plans for a hydrogen pipeline grid already exist, as the so called “European Hydrogen backbone”. As building a completely new pipeline grid is economically not justifiable, a dual-way strategy of repurposing natural gas (NG) pipelines and newly built pipelines is intended. Long distance pipeline grids require regular maintenance and repairs. For natural gas (NG) pipelines in-service welding is state of the art. Concepts such as hot-tapping (drilling into pressurized pipelines) and “stoppling” (sealing off pipeline sections after installing bypasses or pressure relieves) allow the repair of damaged pipeline sections or the installation of new branches without shutting the pipeline down, which in most cases isn’t possible from an economic standpoint. The EIGA 121/14 guideline already pointed out in 2014 that “a hydrogen hot-tap shall not be considered a routine procedure”. This shows that the determination of the transferability of these repair concepts to hydrogen pipelines is of utmost importance. Due to the degrading effects of hydrogen on mechanical proper-ties, commonly referred to as “hydrogen embrittlement” it is necessary to understand and investigate the occurring effects. In the special case of repair welding on in-service hydrogen pipelines an increased hydro-gen uptake due to a large heat input and microstructural changes in the material needs to be considered. Therefore, material degradation must be investigated to determine whether modifications of repair procedures are necessary to ensure a reliable and safe hydrogen transportation via pipelines. For this reason, this paper gives an overview on existing weld repair concepts and its risks and limitations in terms of hydrogen absorption and possible embrittlement effects when transferred to hydrogen pipelines. The complexity lies in a large variety of materials (low alloyed steels), pipeline diameters and corresponding welded joints. The material compatibility of materials in used (repurposed NG-pipelines) and new condition must be investigated. Particularly for repurposed/used pipelines the effect of a pre-matured/corroded inner surface and sometimes insufficient documentation of the material “history” needs to be considered. An overview on ongoing and completed R&D-projects with respect to repair concepts for hydrogen pipelines and hydrogen effects on pipeline materials is given. The focus hereby lies on possible methods of material testing and modeling. Its current difficulties, limits and possible solution will be discussed.
T2 - IIW Intermediate Meeting, Com. II-A
CY - Incheon, Republic of Korea
DA - 12.03.2024
KW - Hydrogen
KW - Repair welding
KW - Pipelines
KW - In-service
PY - 2024
AN - OPUS4-59674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Combined effect of heating rate and restraint condition on stress relief cracking susceptibility during PWHT of thick-walled Cr-Mo-V steel submerged arc welded joints
N2 - Contemporary steels creep-resistant steels like the 13CrMoV9-10 are used as thick plates e.g., for applications in hydrocrackers. The large plate thickness requires high efficiency welding processes like submerged arc welding (SAW) and a mandatory post weld heat treatment (PWHT). The PWHT-parameters stem from a combination of empirical knowledge and traditional experiments on free shrinking (FS) welds. In that connection, the formation of so-called stress-relief cracking (SRC) must be anticipated. The SRC susceptibility of a welded component is a complex combination and interaction of com-ponent specific, thermal, and metallurgical factors. Many of which have to date not been conclusively researched. For example, it is well known that SRCs develop during PWHT due to formation and growth of carbides on prior austenite grain boundaries, resulting in a significant hardness increase (secondary hardening) and toughness decrease. This leads to a high SRC susceptibility of the coarse grain heat-affected zone (CGHAZ) of the last weld bead during PWHT. This is intensified in case of high residual stresses from the component-specific, structurally induced stiffness. In combination with multi-layer welding this leads to a multiaxial stress distribution. Nonetheless, the combined effect of PWHT and high-residual stresses on the SRC formation is merely unknown. For that reason, this study presents the effect of different heating rates in conjunction with a certain component stiffness. For that reason, SAW joints of 13CrMoV9-10 steel were investigated under FS and defined external restraint condition.
T2 - IIW Intermediate Meeting, Com. II-A
CY - Incheon, Republic of Korea
DA - 12.03.2024
KW - Stress relief cracking
KW - Welding
KW - Post weld heat treatment
KW - Submerged arc welding
KW - Cr-Mo-V steel
KW - Creep-resisting steel
PY - 2024
AN - OPUS4-59673
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Call for interested people to contribute to series of comprehensive papers on welding and joining of components for sustainable energy systems
N2 - Joining and welding technologies are of high importance for the manufacturing of components and parts used in sustainable energy generation, conversion, and transport. In that connection, offshore and on-shore installed wind turbines are of high interest for the generation of electrical energy as well as photo-voltaic systems (solar cells). The electricity can be either directly transported or conversed via power-to-gas e.g., to hydrogen. In that scope, electrolyzer up to MW-range are of interest as well as the conver-sion back to electricity via fuel cells. In addition, hydrogen is a key element of the decarburization of in-dustries as well as the mobility sector encompassing sea, air and land transportation driven by hydrogen or its derivates. Well-known examples cover the direct reduction of iron ore to replace the conventional blast furnace process up to gas turbines or fuel cells for home-end use. All mentioned technologies re-quire reliable components, which are to a high extend dependent on joining and especially welding pro-cessing of materials. Especially, the (petro-) chemical industry has many years of experience with both materials used in hydrogen applications. The challenge is e.g., the transition to mass production of sys-tem components of electrolyzers/fuel cells and for distribution grids. At this point, the scalability of cur-rently applied joining processes often limits the economic efficiency, whereas especially laser welding or additive manufacturing will be of high interest. In that connection, it is very important to provide answers by joint research of universities, institutes, and industrial companies. Very often, solutions are already available and “just” have to be investigated and adapted for the new application, like repair welding of NG pipelines. For that reason, we want to set up a series of comprehensive papers with the aforementioned title. The idea is to get an in-depth but manageable overview of the importance of joining technologies in sustaina-ble energy generation, conversion, and transport encompassing current processes, limitations, and fur-ther perspectives. In that connection, the additive manufacturing is gaining more and more attention. If applicable, current challenges in the adaption or creation of new standards/regulations shall be addressed.
T2 - IIW Intermediate Meeting, Com. II-A
CY - Incheon, Republic of Korea
DA - 12.03.2024
KW - Hydrogen
KW - Welding
KW - Comprehensive study
KW - Component manufatcturing
KW - Additive manufacturing
PY - 2024
AN - OPUS4-59676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Hahn, Oliver
A1 - Nehring, G.
A1 - Freisitzer, R.
A1 - Rabin, Ira
T1 - A study on early european inks from St. Paul in lavanttal
N2 - Typology of Inks
Archives and museums around the world contain a vast number of manuscripts that were written in different inks: carbon inks, plant inks, iron-gall inks and mixed inks. Yet most archaeometric studies of manuscripts focus on the palette of pigments found in illuminated manuscripts whereas identification of the inks is still largely based on cultural-historical studies and visual inspections. One of the reasons of this disproportion in the studies can be explained by the properties of Raman spectroscopy, the technique of choice for identification of pigments. In contrast, this technique is only partially viable when dealing with organic colourants. Brown and Clark discuss these difficulties and the uncertainties of identification of iron-gall inks by Raman spectroscopy in their pioneering work on early medieval Anglo-Saxon manuscripts (K. Brown and R. Clark 2004). To facilitate instrumental analysis of inks, we have developed a protocol that starts with the identification of the inks type (Rabin et al. 2012) which doesn’t require complicated instrumentation and can be carried out by paleographers and codicologists.
Three typological ink classes
The black writing materials used in manuscript production in Antiquity und Middle Ages can be sorted in three typologically different ink classes: soot, plant and iron-gall. Soot ink is a fine dispersion of carbon pigments in a water soluble binding agent; plant-based ink consists of a solution of the tannins extracted from gallnuts or tree bark; iron-gall ink, is produced by mixing a soluble compound of iron (II) with gallic or tannic acid extracted from gallnuts or tree bark. Therefore, iron-gall ink presents a boundary case between solution and dispersion ink, in which a water-soluble preliminary stage oxidizes and evolves into a black, insoluble precipitate similar to the carbon pigments when the writing is exposed to air (Krekel 1999). The additional category of mixed inks, i.e. inks produced by addition of various metals to the soot inks or intentional mixing of iron-gall and soot - based inks started attracting scholarly attention only recently because their significance was established only a short while ago (Brun et al. 2016, Colini 2018, Nehring et al. 2021). We suggest that plant and mixed inks build a bridge from the carbon ink of Antiquity to the properly formulated iron-gall ink that became a standard black ink from the late Middle Ages to the 19th century when it gave way to modern inks.
KW - Early european inks
KW - Typology of Inks
KW - Raman spectroscopy
KW - Illuminated manuscripts
KW - Archaeometric studies
KW - Dispersion of carbon pigments
PY - 2021
VL - 2021
SP - 56
EP - 75
PB - Gazette du livre médiéval
CY - Paris
AN - OPUS4-53844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabin, Ira
ED - D'Angelo, M.
ED - Essler, H.
ED - Nikolardi, F.
T1 - Tracing the same Path
T1 - Tradizione e innovazione nella papirologia ercolanese tra Germania e Italia
T1 - Tradition und Fortschritt in der herkulanischen Papyrologie zwischen Deutschland und Italien
N2 - While studying the socio-geographic history of inks, division 4.5 of the BAM (Bundesanstalt für Materialforschung und Prüfung) together with the Centre for the Study of Manuscript Cultures in Hamburg has developed a protocol for ink analysis.
It consists of a primary screening to determine the type of the ink, and a subsequent in-depth analysis using several spectroscopic techniques. The XRF elemental analysis aims primarily at identifying and characterizing metallic components of inks. Besides the instrumental methods, the paper presents an overview of historic inks in the period of transition from carbon inks of the Antiquity to iron-gall inks commonly used in the Middle Ages.
KW - Carbon ink
KW - Mixed ink
KW - Iron-gall ink
KW - Instrumental analysis of ink
KW - Optical properties of ink
PY - 2021
SN - 0391-1535
VL - 2021
IS - 228
SP - 175
EP - 180
PB - Centro Internazionale per lo Studio dei Papiri Ercolanesi ‘Marcello Gigante’
CY - Napoli, Italy
AN - OPUS4-53975
LA - ita
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Fügetechnik für Wasserstofftechnologien: Ausgewählte Themen und Herausforderungen
N2 - Die Präsentation fasst die Bedeutung der Fügetechnik für Wasserstofftechnologien im Rahmen der Arbeiten für einer Studie (DVS-Berichte Nr. 373) mit besonderer Berücksichtigung der Normung und Regelwerkssetzung zusammen.
T2 - Sitzung des DIN-Gemeinschaftsarbeitsausschusses NA 092 00 05 GA, NAS/NMP: Zerstörende Prüfung von Schweißverbindungen
CY - Online meeting
DA - 10.03.2022
KW - Wasserstoff
KW - Fügetechnik
KW - Schweißen
KW - Wasserstofftechnologien
KW - Bedeutung
PY - 2022
AN - OPUS4-54447
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Ultraschallunterstütztes Fräsen von Eisenaluminid
N2 - Eisenaluminide eignen sich als Werkstoff für sicherheitsrelevante Komponenten welche hohen thermischen, mechanischen und korrosiven Belastungen ausgesetzt sind. Mit ihrer geringen Dichte und der kostengünstigen Verfügbarkeit der Legierungsbestandteile bieten sie ein hohes Marktpotenzial und eignen sich als Substitutionswerkstoff konventioneller Hochtemperaturwerkstoffe. Durch die Verwendung von Dauerformen im Kokillenguss lassen sich FeAl-Bauteile bereits äußerst wirtschaftlich herstellen. Das dabei entstehende komplexe, mehrphasige, sehr feinkörnige Gefüge mit harten Ausscheidungen und hohen Festigkeiten erschwert jedoch eine nachfolgende spanende Bearbeitung mit hohen Belastungen auf Werkzeug und Bauteiloberfläche. Um eine gesamtheitlich wirtschaftliche Herstellungsroute zu ermöglichen, sollen im Hinblick auf die erschwerte Zerspanbarkeit geeignete Werkzeuge und Fräsprozesse entwickelt werden. Durch die Verwendung des hybriden Bearbeitungsverfahrens des ultraschallunterstützten Fräsens können diese Ziele unter Einhaltung der hohen Anforderung an die Oberflächenintegrität sicherheitsrelevanter Bauteile erreicht werden.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium der Otto-von-Guericke Universität Magdeburg
CY - Online meeting
DA - 01.12.2021
KW - Eisenaluminid
KW - Zerspanung
KW - Ultraschallunterstütztes Fräsen
KW - Oberflächenintegrität
PY - 2021
AN - OPUS4-54268
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Bewertungsmethode zur Interaktion von Metallurgie und Reaktionskräften beim PWHT warmfester Stähle
N2 - Die Präsentation fasst die Entwicklung einer Ersatzprüfmethode für sogenannte Stress-Relief-Cracks (SRC) bei dickwandigen und kriechfesten geschweißten Stahlkomponenten zusammen. Über die Kombination von gezielter mechanischer Beanspruchung unter hoher Temperaturbeanspruchung werden die Effekte des Post Weld Heat Treatments auf SRC realistisch erstmal auf Laborskala nachgebildet.
T2 - Sitzung des DIN-Gemeinschaftsarbeitsausschusses NA 092 00 05 GA, NAS/NMP: Zerstörende Prüfung von Schweißverbindungen
CY - Online meeting
DA - 10.03.2022
KW - PWHT
KW - Warmfeste Stähle
KW - UP Schweißen
KW - Metallurgie
KW - Stress relief cracking
PY - 2022
AN - OPUS4-54448
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cohen, Zina
A1 - Hahn, Oliver
A1 - Rabin, Ira
ED - Lattuati-Derieux, Agnès
ED - Ribeyrol, Charlotte
ED - Heginbotham, Arlen
T1 - Black Carolingian inks under examination. Part 1: recipes and literature survey
N2 - Black writing materials of different types and compositions have varied in use over time and different geographical regions. With this paper, we would like to contribute to their study by listing and reviewing recipes for black writing inks that were in circulation in the Carolingian Empire as well as by referencing the archaeometric analyses of the black inks used in the manuscripts. The studies presented here that involved the humanities and natural sciences provide new insights into how the scholars of the early Medieval Ages organized manuscripts.
N2 - L’emploi des differents types de materiaux d’ecriture noirs et leurs compositions ont varie selon les epoques et les regions. Nous souhaitons ici contribuer a leur etude en repertoriant et en analysant les recettes d’encres de calligraphie noires en circulation dans l’Empire carolingien, ainsi qu’en procedant au referencement des analyses archeometriques des encres noires utilisees dans les manuscrits. Faisant appel aux sciences humaines et aux sciences naturelles, ces analyses apportent un eclairage nouveau sur la maniere dont les savants du haut Moyen Age organisaient les manuscrits.
KW - Ink
KW - Manuscript
KW - Middle Ages
KW - Recipes
KW - Ink analyses
KW - Carolingian
PY - 2023
SN - 1254-7867
VL - 2023
IS - 55
SP - 90
EP - 95
PB - Centre de Recherche et de Restauration des Musées de France
CY - Paris
AN - OPUS4-58839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Reliable hydrogen determination in metallic materials and their weld joints: Parameters and challenges
N2 - In the course of tomorrow's hydrogen-based energy transition, the construction of the corresponding infrastructure will play a central role. The majority of materials used to date are typically welded for component fabrication. In that context, steels are widely applied and can be prone to hydrogen embrittlement. This includes the classical delayed cold cracking during welding processing as well as embrittlement phenomena during operation. For the evaluation of any hydrogen effect on, for example, the mechanical properties of a welded metallic material, the hydrogen content must be precisely determined. In the case of welds, for example, according to ISO 3690, this is the isothermal carrier gas hot extraction (CGHE). CGHE is based on accelerated hydrogen degassing due to thermal activation of hydrogen at elevated temperatures. In addition to the pure quantification of hydrogen, thermal desorption analysis (TDA) with varied heating rates can be used to determine and evaluate the bonding state at microstructural defects in the material. For both techniques, experimental and measurement influences have to be considered, which have a great effect on the result. For CGHE, for example, ISO 3690 suggests different sample geometries as well as minimum extraction times. The present study summarizes results and experiences of numerous investigations with different sample temperatures and geometries (ISO 3690 type B and cylindrical TDA samples) regarding: the influence of the sample surface (polished/welded), measurement accuracies depending on the sample volume as well as the insufficient monitoring of the effect of the PI controller on the extraction temperature. In particular, a deviating extraction temperature to the set temperature, can significantly falsify the measurement results. Based on the results, methods are shown to quickly reach the desired extraction temperature without having to physically interfere with the measurement equipment. This serves to substantially improve the reliability of hydrogen measurement through increased signal stability and accelerated hydrogen desorption. In general, an independent temperature measurement with dummy samples for the selected heating procedure is advisable to exclude possible unwanted temperature influences already before the measurement. In addition (and way more important), the methods described can be transferred directly to industrial applications.
T2 - 47th MPA-Seminar
CY - Stuttgart, Germany
DA - 10.10.2023
KW - Hydrogen assisted cracking
KW - Carrier gas hot extraction
KW - Welding
KW - ISO 3690
KW - Metals
PY - 2023
AN - OPUS4-58677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungsle¬gierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Es werden die Ergebnisse der Mikrostruktur und der Zerspanbarkeit der Modifikationen der MSG-Schweißung der FeNi36-Referenzlegierung mit 0,4 Gew.-% Zr und der Modifikationen der MSG-Schweißung der CoCr-Referenzlegierung mit 1 Gew.-% Zr sowie Hf vorgestellt. Abschließend werden aus den Ergebnissen Handlungsempfehlungen abgeleitet.
T2 - Sitzung der Arbeitsgruppe (AG) V 12 „Additive Fertigung“
CY - Online meeting
DA - 15.11.2023
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
PY - 2023
AN - OPUS4-58859
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Analyzing the impact of individual alloying elements on weld microstructure: In situ chemical composition measurement during TIG welding of Duplex Stainless Steels microstructure
N2 - Various industrial applications require the joining of DSS components. Tungsten Inert Gas (TIG) welding is particularly well-suited for this purpose due to the ability to achieve highly reproducible automated welds. However, during solidification of the weld pool, critical phase ratios of ferrite (α) and austenite (γ) may occur, leading to solidification cracking, increased corrosion susceptibility, lower ductility and critical strength values. Hence, in order to achieve the desired material characteristics, it is crucial to accurately predict the α/γ phase ratio within the weld. Conventionally, the WRC-1992 diagram is employed for this purpose. In our study, we used Laser-Induced Breakdown Spectroscopy (LIBS) to track alterations in the chemical composition of the weld metal on the surface throughout the welding process. One significant benefit of this method is its capability to provide precise and real-time measurements of chemical compositions during welding, both temporally and spatially. In previous investigations, we could develop routines to quantify the measurement of chemical compositions within the weld metal and the Heat-Affected Zone (HAZ). The conducted research focuses on examining the alterations in chemical concentrations of specific alloying elements, namely Cu and Mn as γ-forming elements, and Nb and Cr as α-forming elements, during welding. These changes are measured in real-time using Laser-Induced Breakdown Spectroscopy (LIBS). To achieve this, both the ferrite number, determined through magnetic-inductive techniques, and the weld microstructure are analyzed. Through image-analytical methods, a correlation is established between the microstructure and the LIBS data obtained.
T2 - AJP 2023
CY - Braga, Portugal
DA - 19.10.2023
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
PY - 2023
AN - OPUS4-58657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cohen, Zina
T1 - Material Studies of Torah Scrolls at the Bundesanstalt für Materialforschung und -Prüfung
N2 - In recent years the BAM has been focusing on the characterization of the writing materials of the medieval Torah scrolls. The challenge imposed by the study of this specific type of manuscript led to designing and building dedicated stages to ensure the safety of the scrolls during the analysis. Furthermore, the identification of multiple corrections executed in apparently identical inks required broadening the standard two-step protocol of near infrared reflectography and X-ray fluorescence to include multispectral imaging. This work has prepared the division to participate in the large collaborative project “To roll: Materialisierte Heiligkeit (Materialised Holiness)” based at the Free University, Berlin.
The presentation will demonstrate the aims of the studies, preliminary results and the strategies adopted by the division 4.5 of the BAM.
T2 - EAJS Congress Branching Out: Diversity of Jewish Studies
CY - Frankfurt/Main, Germany
DA - 16.07.2023
KW - Ink analyses
KW - Manuscript studies
KW - Torah Scrolls
KW - X-Ray fluorescence
KW - Middle Ages
PY - 2023
AN - OPUS4-58881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Fügetechnik in Wasserstofftechnologien - Forschungsbedarf für die Branche (Kurzversion)
N2 - Die Studie gibt einen kurzen Überblick über die jetzige Bedeutung der Fügetechnik in Wasserstofftechnologien und über zukünftige Forschungsbedarfe für die Branche in den einzelnen Technologiefeldern Wasserstofferzeugung, -speicherung, -transport und -nutzung. Fügetechnologien haben dabei wesentliche Bedeutung für die erfolgreiche Umsetzung von technischen Komponenten der Wasserstofftechnologien. Die Schwerpunkte bzw. Forschungsbedarfe ergeben sich bspw. durch die Erstellung neuer Infrastruktur für Wasserstoffspeicherung und -transport sowie durch Umnutzung der bestehenden Erdgasinfrastruktur. Bei der Wasserstofferzeugung und -anwendung wird z.B. die Entwicklung effiziente Massenproduktionsmethoden von Elektrolyseuren und Brennstoffzellen einen wichtigen Meilenstein bilden und laserbasierte Fügetechnologien sind hier zum Teil schon etabliert. Die additive Fertigung nimmt dabei eine Querschnittsposition ein und besitzt hohes Anwendungspotential für die Zukunft z.B. für die Fertigung von Komponenten in Gasturbinen. Aus den technischen Fragestellungen und Forschungsbedarfen ergeben sich zudem Herausforderungen für die notwendige Neu- und Weiterentwicklung von technischen Regelwerken und Normen und den Eingang in die Aus- und Weiterbildung von fügetechnischem Fachpersonal.
T2 - DVS Congress 2021
CY - Online meeting
DA - 14.09.2021
KW - Wasserstoff
KW - Fügetechnik
KW - Forschung
KW - Werkstoff
KW - Bedarf
PY - 2021
SN - 978-3-96144-146-4
VL - 371
SP - 612
EP - 624
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-53370
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Czeskleba, Denis
A1 - Kannengießer, Thomas
T1 - Kurzbericht zum Projekt „Entwicklung von Wärmenachbehandlungskonzepten zur Vermeidung von Spannungsrelaxationsrissen an Bauteilen aus hochwarmfesten Stählen“ (DVS-Nr. 01.2261 / IGF-Nr. 20171 N)
N2 - Komponenten aus dickwandigen, hochwarmfesten CrMoV-Stählen erfordern eine anspruchsvolle UP-Schweißverarbeitung. Dabei muss die notwendige Wärmenachbehandlung der Schweißnaht (PWHT) sicher beherrscht werden.
Hier kann u.U. Bauteilversagen infolge von Spannungsrelaxationsrissbildung (SRR) auftreten. Bislang erfolgt die Beurteilung der SRR-Neigung primär über Ersatzgrößen, wie temperaturbedingte Änderung der Härte und Duktilität.
Die Wirkung der konstruktiven Schrumpfbehinderung einer Schweißnaht auf die SRR ist bislang völlig unbekannt.
Hier setzt das Forschungsprojekt an, hinsichtlich der Gewinnung und Optimierung der Parameter für die PWHT unter realitätsnahen Bauteilsteif igkeiten (def inierte Einspannbedingung) mit dem Ziel der SRR-Vermeidung. Am Beispiel des niedriglegierten, hochwarmfesten Stahls 13CrMoV9-10 wurden UP- Schweißungen unter industriepraktischen Bedingungen freischrumpfend bzw. unter definierter Schrumpfbehinderung durchgeführt. Diese wurden mit unterschiedlichen PWHT-Szenarien (Variation der Auf heizrate und Endtemperatur) beaufschlagt. Die Ergebnisse des Projektes DVS 01.2261 / IGF 20171 N werden in diesem Beitrag vorgestellt, wie Aussagen zur SRR-Suszeptibilität in Abhängigkeit von Mikrostruktur und vorliegender mehrachsiger mechanischer Beanspruchung der Schweißnaht vor/während des PWHT. Für einen kritischen Zustand sind hohe Kräfte / Spannungen notwendig, die in freischrumpfenden Schweißversuchen u.U. nicht abbildbar sind. Die Berücksichtigung des mikrostrukturspezifischen Ausscheidungsverhaltens (in Schweißgut und Wärmeeinflusszone) unter realitätsnahen Einspannbedingungen ist für die Bewertung einer SRR-Suszeptibilität notwendig. Instrumentierte Schweißversuche unter definierter Schrumpfbehinderung ermöglichen hier das Monitoring der entstehenden Reaktionskräfte, -momente bzw. -spannungen. Ausgehend von diesem Referenzzustand erfolgte die Applikation der PWHT-Szenarien bzw. deren praktische Überprüfung. Zusätzlich wurde eine Ersatzprüfmethodik entwickelt, die die Betrachtung der mikrostrukturspezifischen SRR-Suszeptibilität unter Beibehaltung der äußeren Schrumpfbehinderung der Schweißnaht während des PWHT ermöglicht. Hierdurch wird die Bauteilübertragbarkeit ermöglicht und eine Transfergröße geschaffen, welche die Bauteilbewertung hinsichtlich der SRR-Neigung umfasst.
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - UP-Schweißen
KW - Spannungsrelaxationsriss
KW - Forschungsprojekt
KW - Dickblech
KW - Wärmebehandlung
PY - 2022
SN - 978-3-96144-190-7
SP - 76
EP - 82
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-55944
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical Concentration by Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the work is to quantitatively measure the chemical composition in the weld seam of various DSS and to identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material. Spectra were recorded every 1.3 s at a spacing of approximately 2 mm. During the cooling process the location of the measurement was not changed. The LIBS method is proofed to be suitable for the quantitative representation of the chemical compositions during the welding process.
T2 - 6th International Conference on Advances in Solidification Processes
CY - Le Bischenberg, France
DA - 20.06.2022
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
PY - 2022
AN - OPUS4-55116
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - First measurements of chemical composition changes during cooling of duplex stainless steel during TIG welding using laser-induced breakdown spectroscopy (LIBS)
N2 - Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the work is to quantitatively measure the chemical composition in the weld seam of various DSS and to identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material. Spectra were recorded every 1.3 s at a spacing of approximately 2 mm. During the cooling process the location of the measurement was not changed. The LIBS method is proofed to be suitable for the quantitative representation of the chemical compositions during the welding process.
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
PY - 2022
AN - OPUS4-55922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
A1 - Treutler, K.
A1 - Gehling, T.
A1 - Eissel, A.
A1 - Wesling, V.
T1 - In situ Messung der chemischen Konzentration in der Schmelze während des WIG-Schweißens von Duplexstählen
N2 - Duplexstähle besitzen ein zweiphasiges Gefüge und werden aufgrund ihrer verbesserten Schweißeignung gegenüber den Vollausteniten häufig im Anlagen- bzw. Apparatebau eingesetzt. Aufgrund der hohen Abkühlgeschwindigkeit und dem Abbrand von Legierungselementen kommt es zu einer Ferritisierung des Schweißguts und damit zu einer Degradation der mechanischen Eigenschaften. Zur Vorhersage des Phasenverhältnisses im Schweißgut wird das WRC1992-Diagramm genutzt. Dieses Diagramm zeigt einige Ungenauigkeiten und benötigt zur genaueren Vorhersage der Phasenverhältnisse eine Überarbeitung. Um den Einfluss einzelner Elemente auf das Schweißnahtmikrogefüge besser zu verstehen, wurden drahtförmige Schweißzusatzwerkstoffe mit dem Ferrit-Bildner Nb und dem Austenit-Bildner Cu beschichtet und für Schweißungen verwendet. Die Messmethode der Laser-induzierten Plasmaspektroskopie (LIBS) bietet hier eine gute Möglichkeit der in situ Überwachung der chemischen Konzentrationen, während des WIG-Schweißens von Duplexstählen. Die LIBS-Messergebnisse, konnten mit der Ferritnummer und der Schweißnahtmikrostruktur korreliert werden.
T2 - Symposium Materialtechnik der TU Clausthal
CY - Clausthal-Zellerfeld, Germany
DA - 23.02.2023
KW - LIBS
KW - In situ measurement
KW - WRC 1992 diagram
KW - Dduplex stainless steel
KW - TIG welding
PY - 2023
VL - 12
SP - 612
EP - 627
PB - Shaker
CY - Aachen
AN - OPUS4-57991
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Analyse der chemischen Konzentrationen während des WIG-Schweißens von Duplexstählen mittels Laser induzierter Plasmaspektroskopie (LIPS)
N2 - Die Kombination aus hoher Korrosionsbeständigkeit und guten mechanischen Eigenschaften von Duplexstählen (DSS) ist auf ihre chemische Zusammensetzung und das ausgewogene Phasenverhältnis von Ferrit (α) und Austenit (γ) zurückzuführen.
Viele industrielle Anwendungen erfordern eine stoffschlüssige Verbindung von DSS. Das Wolfram-Inertgas-Schweißen (WIG) ist relativ einfach zu handhaben, benötigt nur wenig Platz und ermöglicht ein automatisiertes Schweißen, mit sehr hoher Reproduzierbarkeit und ist daher hervorragend zum Schweißen von DSS.
Während der Erstarrung dieser Dualphasenstähle kann es zu kritischen Phasenverhältnissen von α und γ kommen, was zu Erstarrungsrissen, Korrosionsanfälligkeit, geringerer Duktilität und kritischen Festigkeitswerten führt. Um die gewünschten Werkstoffeigenschaften zu erhalten, muss daher die α/γ-Verteilung zuverlässig vorhergesagt werden. Dies geschieht in der Regel mit Hilfe des WRC1992-Diagramms. Die Vorhersagegenauigkeit des Ferritgehalts in diesem Diagramm ist jedoch meist nicht genau genug und muss daher optimiert werden. Daher ist es notwendig, selbst kleinste Veränderungen in der chemischen Zusammensetzung des Schweißguts idealerweise während des Schweißens zu überwachen. Dies wird in diesen Experimenten mit Hilfe der laser-induzierten Plasmaspektroskopie (LIBS) durchgeführt. Ein großer Vorteil dieser Technik ist die hochgenaue zeit- und ortsaufgelöste Messung der chemischen Zusammensetzung während des Schweißens. In vorherigen Arbeiten wurde bereits die chemische Zusammensetzung im Schweißgut und der WEZ quantifiziert. In der präsentierten Untersuchung wird der Einfluss einzelner Elemente, wie Nb und Cu, auf das resultierende Schweißmikrogefüge untersucht.
T2 - BMDK der Universität Magdeburg
CY - Magdeburg, Germany
DA - 05.07.2023
KW - LIBS
KW - In situ measurement
KW - WRC 1992 diagram
KW - TIG welding
KW - Duplex stainless steels
PY - 2023
AN - OPUS4-57873
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Increasing the Significance of Varestraint Tests through Improved Crack Evaluation
N2 - The contribution describes a newly developed software tool for crack identification and selection in Modified Varestraint Transvarestraint (MVT) testing. From the digital crack information, in addition to the classical results, such as Total Crack Length (TCL) and Maximum Crack Length (MCL), advanced evaluations can be applied, taking into account the loading and welding parameters. A numerical parameter study is conducted to demonstrate how the isolated variation of individual welding and loading parameters, affects the crack lengths that can potentially be expected based on the machine specifics. An alternative crack criterion is presented that evaluates the crack formation in relation to the machine behavior. Some examples demonstrate the possibilities and limitations of the approach. The criterion can be used to compare and transfer the results of different varestraint test variants.
T2 - IIW Annual Assembly, Comission II-C
CY - Singapore
DA - 17.07.2023
KW - Solidification cracking
KW - Varestraint-Test
PY - 2023
AN - OPUS4-57984
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reinsch, Stefan
T1 - Oriented Surface Crystallization in Glasses
N2 - Up to now, oriented surface crystallization phenomena are discussed controversially, and related studies are restricted to few glasses. For silicate glasses we found a good correlation between the calculated surface energy of crystal faces and oriented surface nucleation. Surface energies were estimated assuming that crystal surfaces resemble minimum energy crack paths along the given crystal plane. This concept was successfully applied at the Institute of Physics of Rennes in calculating fracture surface energies of glasses. Several oriented nucleation phenomena can be herby explained assuming that high energy crystal surfaces tend to be wetted by the melt. This would minimize the total interfacial energy of the nucleus. Furthermore, we will discuss the evolution of the microstructure and its effect on the preferred crystal orientation.
T2 - ACerS GOMD 2024- Glass & Optical Materials Division Meeting
CY - Las Vegas, NV, USA
DA - 19.05.2024
KW - Surface nucleation
KW - Oriented surface crystallization
KW - Surface energy
PY - 2024
AN - OPUS4-60238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, P.
T1 - The contribution of the Platform MaterialDigital (PMD) in building up a Materials Data Space - Application to glass design and manufacturing
N2 - Suitable material solutions are of key importance in designing and producing components for engineering systems – either for functional or structural applications. Materials data are generated, transferred, and introduced at each step along the complete life cycle of a component. A reliable
materials data space is therefore crucial in the digital transformation of an industrial branch.
A great challenge in establishing a materials data space lies in the complexity and diversity of materials science and engineering. It must be able to handle data from different knowledge areas over several magnitudes of length scale.
The Platform MaterialDigital (PMD) is expected to network a large number of repositories of materials data, allowing the direct contact of different stakeholders as materials producers, testing labs, designers and end users. Following the FAIR principles, it will promote the semantic
interoperability across the frontiers of materials classes. In the frame of a large joint initiative, PMD works intensively together with currently near 20 research consortia in promoting this exchange (www.material-digital.de).
In this presentation we will describe the status of our Platform MaterialDigital. We will also present in more detail the activities of GlasDigital, one of the joint projects mentioned above dealing with the digitalization of glass design and manufacturing.
(https://www.bam.de/Content/EN/Projects/GlasDigital/glasdigital.html)
T2 - OntoCommons Workshop
CY - Berlin, Germany
DA - 04.04.2023
KW - Ontology
KW - Materials Data Space
KW - PMD
KW - Glass
PY - 2023
AN - OPUS4-60371
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reinsch, Stefan
T1 - A new robot-assisted compositional screening method
N2 - The system Na2O.B2O3-SiO2 (NBS) is the basis of many industrial glass applications and therefore one of the most studied systems at all. Glass formation is possible over a wide compositional range, but the system also contains ranges of pronounced phase separation and crystallization tendency. Despite its importance, experimental data are limited to few compositional areas. The general understanding and modelling of glass formation, phase separation, and crystallization in this system would therefore be easier if small step melt series could be studied. The efficient melting of such glass series is now possible with the new robotic glass melting system at the Federal Institute for Materials Research and Testing (BAM, Division Glasses). Using three exemplary joins within this NBS system, the small step changes of glass transition temperature (Tg), crystallization behavior as well as glass density (Roh) was studied. Additionally, experimental Tg and Roh data were compared with their modeled counterparts using SciGlass and a newly developed DFT model, respectively.
T2 - Annual meeting of the French Union for Science and Glass Technology (USTV) and the 96th Annual Meeting of the German Society of Glass Technology - USTV-DGG joint meeting.
CY - Orléans, France
DA - 22.05.2023
KW - Robot-assisted galss melting
KW - Sodiumborosilicate glasses
KW - Density
KW - Glass transformation temperature
KW - Property simulation
PY - 2023
AN - OPUS4-58724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Bedingungen für den schadensfreien Einsatz von nichtrostenden Stählen
N2 - Der Vortrag beleuchtet die Passivität von nichtrostenden Stählen und erläutert anhand von praktischen Schadensfällen den korrosionsschutzgerechten Einsatz dieser Werkstoffe
T2 - VdEh Seminar "Nichtrostende Stähle - Eigenschaften und Anwendungen"
CY - Düsseldorf, Germany
DA - 06.06.2023
KW - Korrosion
KW - Nichtrostende Stähle
KW - Passivität
KW - PREN
PY - 2023
AN - OPUS4-57618
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Spannungsrisskorrosion an Bauteilen aus nichtrostenden Edelstählen - Bittere Erfahrungen in der Vergangenheit und sichere Verwendung in der Gegenwart
N2 - Der Vortrag beschreibt die grundlegenden Voraussetzungen für das Auftreten von Spannungsrisskorrosion an nichtrostenden Stählen und erläutert den Schadensmechanismus bis zum Versagen des Werkstoffs. Abgeleitet von den notwendigen Voraussetzungen für das Auftreten von SpRK werden werkstoff, medien und belastungsabhängige Einflussfaktoren erläutert, die die Beständigkeit der Werkstoffe gegenüber dieser Schädigungsart positiv wie auch negativ verändern. Weiterhin werden historische und aktuelle Schadensfälle präsentiert und Ursachen, Folgen und mögliche Fehlervermeidung disktutiert. Abschließend werden Prüfverfahren zum Nachweis der Empfindlichkeit von nichtrostenden Stählen gegenüber SpRK näher beschrieben.
T2 - fkss Infotag 01/2024
CY - Esslingen, Germany
DA - 11.01.2024
KW - Korrosion
KW - Spannungsrisskorrosion
KW - Nichtrostender Stahl
KW - Korrosionsprüfung
KW - Schwimmhallen
PY - 2024
AN - OPUS4-59355
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - Nichtrostender Stahl im Kontakt mit anderen Werkstoffen
N2 - Der Beitrag zeigt die Mechanismen, Voraussetzungen und Einflussgrößen der Bimetallkorrosion wichtiger Werkstoffe im Kontakt mit nichtrostenden Stahl anhand von verschiedenen Beispielen. Darüber hinaus wird das Korrosionsverhalten von nichtrostenden Stahl im Kontakt mit Holz als saurer Baustoff und mit Beton als alkalischer Baustoff beschrieben.
T2 - VDEh Seminar Korrosionsverhalten nichtrostender Stähle
CY - Düsseldorf, Germany
DA - 30.01.2024
KW - Bimetallkorrosion
KW - Nichtrostender Stahl
KW - Saure und alkalische Baustoffe
KW - Potentialbeeinflussung der Kontaktpartner
PY - 2024
AN - OPUS4-59456
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Arendt, F.
A1 - de Camargo, Andrea Simone Stucchi
A1 - Chen, Y.-F.
A1 - Gogula, S.
A1 - Kilo, M.
A1 - Waurischk, Tina
T1 - GlasDigital
N2 - Der aktuelle Stand des MateriaDigital Projektes GlasDigital wird vorgestellt. Hierbei wird allgemein die Problem- und Zielstellung präsentiert, als auch auf 2 separaten Postern die Ergebnisse. Diese beinhalten zum Einen die smarte Gestaltung der robotergestützten Glasschmelzanlage der BAM inkl. Analytik und zum Anderen die Digitalisierungsbestrebungen im Bereich Glas, d.h. ML-gestützte C-S-P-Simulation, Ontologie für den Werkstoff Glas, Digitaler Zwilling des Gießprozesses.
T2 - PMD Vollversammlung 2023
CY - Karlsruhe, Germany
DA - 21.09.2023
KW - GlasDigital
KW - Ontologie
KW - Bildanalyse
KW - Simulation
KW - Roboter
KW - Digitalisierung
PY - 2023
AN - OPUS4-58734
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kilo, M.
T1 - New Approaches for the Preparation and Characterisation of New Glasses
N2 - The new robot-assisted glass melting device at BAM is presented by the manufacturing team within the joint project GlasDigital together with an automatic thermo-optical measurement technique.
T2 - UST-DGG joint meeting
CY - Orléans, France
DA - 23.05.2023
KW - Glass melting
KW - Thermo-optical measurement
PY - 2023
AN - OPUS4-58733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
A1 - Müller, Thoralf
A1 - Ebell, Gino
ED - Pillai, Radhakrishna G.
T1 - Development of a new test method for assessing the susceptibility of prestressing steels to hydrogen-induced stress corrosion cracking
N2 - For prestressing steel’s factory production control, approvals, and continuous surveillance in Germany, a susceptibility test against hydrogen-induced stress corrosion cracking is performed. The measured time to fracture results (in hours) must be reproducible and reliable in the test. ISO 15630-3 gives currently unpersuasive and diverging results using a free corrosion approach for hydrogen charging. A newly developed test method uses cathodic polarization for defined hydrogen charging instead of an uncontrolled and variable electron supply by metal dissolution during free corrosion. With this new test method, a reliable differentiation is possible between highly susceptible-known “old-type” quenched and tempered prestressing steel, i.e., Neptun, Hennigsdorfer, Sigma, and currently approved cold-drawn wires St 1470/1670 (CDS-1670) and St 1570/1770 (CDS-1770). The reproducibility of the new test method was evaluated in a round-robin test with eight attended testing institutes on a St 1470/1670 (CDS-1670) batch.
T2 - Conference CONSEC24
CY - Chennai, India
DA - 25.09.2024
KW - Hydrogen charging
KW - ISO 15630-3
KW - Prestressing steels
KW - Round-robin
KW - Stress corrosion cracking
PY - 2024
UR - https://consec24.com/#
SP - 1
EP - 8
PB - Indian Institute of Technology (IIT) Madras, Centre of Excellence on Technologies for Low Carbon & Lean Construction
CY - Chennai, India
AN - OPUS4-61163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reinsch, Stefan
T1 - Oriented Surface Crystallization in Glasses
N2 - Up to now, oriented surface crystallization phenomena are discussed controversially, and related studies are restricted to few glasses. For silicate glasses we found a good correlation between the calculated surface energy of crystal faces and oriented surface nucleation. Surface energies were estimated assuming that crystal surfaces resemble minimum energy crack paths along the given crystal plane. This concept was successfully applied at the Institute of Physics of Rennes in calculating fracture surface energies of glasses. Several oriented nucleation phenomena can be herby explained assuming that high energy crystal surfaces tend to be wetted by the melt. This would minimize the total interfacial energy of the nucleus. Furthermore, we will discuss the evolution of the microstructure and its effect on the preferred crystal orientation.
T2 - 13th International Symposium on Crystallization in Glasses and Liquids
CY - Orléans, France
DA - 24.09.2024
KW - Surface crystallization
KW - Surface energy
KW - Crystal orientation
KW - Silicate glass
PY - 2024
AN - OPUS4-62219
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - GlassDigital: Digital Infrastructure for Data-Driven High-Throughput Glass Development
N2 - Gläser zeichnen sich durch eine breite und kontinuierlich abstimmbare chemische Zusammensetzung sowie einzigartige Formgebungstechniken aus, was sie oft zur Schlüsselkomponente moderner Hochtechnologien macht. Die Glasentwicklung ist jedoch oft noch zu kosten-, zeit- und energieintensiv. Der Einsatz von robotergestützten Schmelzsystemen, eingebettet in eine Ontologie-basierte digitale Umgebung, soll diese Probleme in Zukunft überwinden. Im Rahmen der BMBF Forschungsinitiative MaterialDigital unternimmt das Verbundprojekt GlasDigital „Datengetriebener Workflow für die beschleunigte Entwicklung von Glas“ erste Schritte in diese Richtung. Das Projektkonsortium, an dem das Fraunhofer ISC in Würzburg, die Friedrich-Schiller-Universität Jena (OSIM), die Technische Universität Clausthal (INW) und die Bundesanstalt für Materialforschung und -prüfung (BAM, Fachgruppe Glas) beteiligt sind, will alle wesentlichen Basiskomponenten für eine beschleunigte datengetriebene Glasentwicklung zusammenführen. Zu diesem Zweck wird ein robotergestütztes Hochdurchsatz-Glasschmelzsystem mit neuartigen Inline-Sensoren zur Prozessüberwachung, auf maschinellem Lernen (ML) basierenden adaptiven Algorithmen zur Prozessüberwachung und -optimierung, neuartigen Werkzeugen für die Hochdurchsatz-Glasanalyse sowie ML-basierten Algorithmen zum Glasdesign, Data Mining sowie Eigenschafts- und Prozessmodellierung ausgestattet. Der Vortrag gibt einen Überblick darüber, wie all diese Komponenten miteinander verzahnt sind, und veranschaulicht ihre Nutzbarkeit anhand einiger Beispiele.
T2 - HVG-Fortbildungskurs
CY - Offenbach, Germany
DA - 27.11.2023
KW - Glas
KW - Ontology
KW - Workflow
KW - Simulation
KW - Robotic melting
PY - 2023
AN - OPUS4-60386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - GlasDigital - Datengetriebener Workflow für die beschleunigte Glasentwicklung
N2 - Im Projekt GlasDigital sollen digitale Werkzeuge für die Hochdurchsatzentwicklung neuartiger Glaswerkstoffe erarbeitet werden. Dies soll durch die Kombination robotischer Syntheseverfahren mit selbstlernenden Maschinen und ihre Einbindung in eine Ontologie-basierte digitale Infrastruktur realisiert werden.
T2 - 4. Fachsymposium der Fachgruppe Glasapparatebauer
CY - Mitterteich, Germany
DA - 13.06.2024
KW - Glas
KW - Ontology
KW - Data Space
KW - Simulation
KW - Workflow
KW - Robotische Schmelzanlage
PY - 2024
AN - OPUS4-60388
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - Digital infrastructure for accelerated glass development
N2 - Glasses stand out by their wide and continuously tunable chemical composition and large variety of unique shaping techniques making them a key component of modern high technologies. Glass development, however, is still often too cost-, time- and energy-intensive. The use of robotic melting systems embedded in an ontology-based digital environment is intended to overcome these problems in future.
For this purpose, a robotic high throughput glass melting system is equipped with novel inline sensors for process monitoring, machine learning (ML)-based, adaptive algorithms for process monitoring and optimization, novel tools for high throughput glass analysis and ML-based algorithms for glass design. This includes software tools for data mining as well as property and process modelling. The presentation provides an overview of how all these tools merge into a digital infrastructure and illustrates their usability using examples.
All infrastructural parts were developed by a consortium consisting of the Fraunhofer ISC in Würzburg, the Friedrich-Schiller-University Jena (OSIM), the Clausthal University of Technology (INW) and the Federal Institute for Materials Research and Testing (BAM, Division Glasses) as part of a joint project of the German research initiative MaterialDigital.
T2 - 97. Glass-Technology Conference
CY - Aachen, Germany
DA - 27.05.2024
KW - Glass
KW - Robotic melting
KW - Ontologie
KW - Simulation
KW - Workflow
KW - Data Space
KW - Digital Twin
PY - 2024
AN - OPUS4-60387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - GlasDigital: Data-driven workflow for accelerated glass development
N2 - Glasses stand out by their wide and continuously tunable chemical composition and large variety of unique shaping techniques making them a key component of modern high technologies. Glass development, however, is still often too cost-, time- and energy-intensive. The use of robotic melting systems embedded in an ontology-based digital environment is intended to overcome these problems in future. As part of the German research initiative MaterialDigital, the joint project GlasDigital takes first steps in this direction. The project consortium involves the Fraunhofer ISC in Würzburg, the Friedrich Schiller University Jena (OSIM), the Clausthal University of Technology (INW), and the Federal Institute for Materials Research and Testing (BAM, Division Glasses) and aims to combine all main basic components required for accelerated data driven glass development. For this purpose, a robotic high throughput glass melting system is equipped with novel inline sensors for process monitoring, machine learning (ML)-based, adaptive algorithms for process monitoring and optimization, novel tools for high throughput glass analysis and ML-based algorithms for glass design, including software tools for data mining as well as property and process modelling. The talk gives an overview how all these tools are interconnected and illustrates their usability with some examples.
T2 - USTV-DGG joint meeting
CY - Orleans, France
DA - 22.05.2023
KW - Glass
KW - Ontology
KW - Data Space
KW - Workflow
KW - Robotic melting
PY - 2023
AN - OPUS4-60372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - New Stress Corrosion Cracking Test Method for Prestressing Steel Wires
N2 - This presentation at CONSEC24 gives an overview of the new stress corrosion cracking test for prestressing steel wires using cathodic polarisation. Design of Experiments (DOE) studies on prestressing levels and cathodic current density on time to fracture will be presented, testing different prestressing steels. Finally, an experimental solution for testing strands is proposed.
T2 - 10th International Conference on CONcrete under SEvere Conditions – Environment and Loading 2024 (CONSEC24)
CY - Chennai, India
DA - 25.09.2024
KW - Prestressing Steels
KW - ISO 15630-3
KW - Hydrogen-induced Stress Corrosion Cracking
KW - Brittle Fracture
KW - Hydrogen Charging
PY - 2024
AN - OPUS4-61166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
A1 - Lehmann, Jens
T1 - Einfluss der Oberflächennachbearbeitung auf die Korrosionsbeständigkeit von Schweißnähten
N2 - Bedingung für den schadensfreien Einsatz nichtrostender Stähle ist die vollständige Ausbildung der Passivschicht. Voraussetzung dafür sind glatte, blanke, saubere Oberfläche, eine gleichmäßige Elementverteilung, wenig Ausscheidungen und Verunreinigungen. Eine mögliche Beeinflussung der Gefügeausbildung durch Warmumformung und durch die schweißtechnische Verarbeitung sind zu beachten. Anlauffarben müssen durch geeignete geeignete chemische bzw. mechanische Nachbehandlung entfernt werden. Eine ausreichende Nachbehandlung kann durch elektrochemische Prüfverfahren ebenso sichergestellt werden wie mittels der KorroPad-Prüfmethode. Letzte ist einfach und schnell in der Anwendung und ermöglicht es dem Verarbeiter, die Geeignetheit einer Nachbehandlung zu überprüfen.
T2 - ISER Kursleiterfortbildung HWK Dresden
CY - Dresden, Germany
DA - 23.09.2024
KW - Korrosionsschutz
KW - KorroPad
KW - Nichtrostender Stahl
KW - Prüfmethoden
KW - Schweißnaht
PY - 2024
AN - OPUS4-61382
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Bedingungen für den schadensfreien Einsatz von nichtrostenden Stählen
N2 - Unter Passivität versteht man den Korrosionsschutz durch dünne, festhaftende Schichten aus Korrosionsprodukten. Für den schadensfreien Einsatz nichtrostender Stähle ergeben sich daraus zwei grundsätzliche Anforderungen.
Erstens muss sich die Passivschicht vollständig ausbilden können. Dabei sind die Oberflächenausführung, die mechanische Bearbeitung, die Elementverteilung, Ausscheidungen, die Wärmeeinbringung z.B. bei der schweißtechnischen Verarbeitung, Anlauffarben, sowie die chemische Nachbehandlung bzw. Konditionierung der Oberflächen von großer Bedeutung. Zweitens muss die Repassivierung von Defektstellen unter den Einsatzbedingungen möglich sein. Für das Repassivierungsvermögen sind die Legierungszusammensetzung, mögliche kritische Betriebszustände, prozessbedingte Besonderheiten, wie etwa Stagnationsbedingungen und Reinigungsprozesse von Bedeutung.
T2 - Nichtrostende Stähle - Eigenschaften und Anwendungen
CY - Dusseldorf, Germany
DA - 11.06.2024
KW - Korrosion
KW - Passivität
KW - Dauerhaftigkeit
KW - Schadensursachen
PY - 2024
AN - OPUS4-60298
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blaeß, Carsten
T1 - Undesired Foaming of Silicate Glass Powders
N2 - The manufacture of sintered glasses and glass-ceramics, glass matrix composites, and glass-bounded ceramics or pastes is often affected by un-expected gas bubble formation also named foaming. Against this background, in this presentation the main aspects and possible reasons of foaming are shown for completely different glass powders: a barium silicate glass powders used as SOFC sealants, and bioactive glass powders using different powder milling procedures.
Sintering and foaming were measured by means of heating microscopy backed up by XRD, differential thermal analysis (DTA), vacuum hot extraction (VHE), optical and electron microscopy, and infrared spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS).
Different densification was reached followed by significant foaming starting partly immediately, partly at higher temperature. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the milling atmosphere significantly affects the foaming of uniaxially pressed powder compacts sintered in air.
VHE studies show that foaming is driven by carbon gases and carbonates were detected by Infrared spectroscopy to provide the major foaming source. Carbonates could be detected even after heating to 750 °C, which hints on a thermally very stable species or mechanical trapping or encapsulating of CO2. Otherwise, dark gray compact colors for milling in isopropanol indicate the presence of residual carbon as well. Its significant contribution to foaming, however, could not be proved and might be limited by the diffusivity of oxygen needed for carbon oxidation to carbon gas.
T2 - Seminário de Laboratório de Materiais Vítreos (LaMaV) de Departamento de Engenharia de Materiais (DEMa), Universidade Federal São Carlos UFSCar)
CY - Saint Charles, Brazil
DA - 06.06.2024
KW - Bioactive
KW - Foaming
KW - Glass
KW - Crystallization
KW - Viscose sintering
PY - 2024
AN - OPUS4-60245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Diegeler, A.
T1 - Digital material data based glass screening for the systematic development of new glasses
N2 - Current German developments for accelerated glass development is presented to an international audience at GOMD 2023. The focus is on a screening device which is embedded in a digital infrastructure.
T2 - GOMD
CY - New Orleans, LA, USA
DA - 04.06.2023
KW - Glass
KW - Robotic melting
PY - 2023
AN - OPUS4-60376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kilo, M.
T1 - New Approaches for the Preparation and Characterisation of New Glasses
N2 - The new robot-assisted glass melting device at BAM is presented by the manufacturing team within the joint project GlasDigital together with an automatic thermo-optical measurement technique.
T2 - USTV-DGG joint meeting
CY - Orleans, France
DA - 22.05.2023
KW - Glass
KW - Robotic melting
PY - 2023
AN - OPUS4-60374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - GlasDigital
N2 - Der aktuelle Stand (Sep 2023) des Projekts GlasDigital wird präsentiert. Der Fokus liegt hierbei auf einer knappen Übersicht, aus der die nachhaltigen Beiträge für die Innovationsplattform MaterialDigital hervorgehen.
T2 - PMD Vollversammlung
CY - Karlsruhe, Germany
DA - 21.09.2023
KW - Glas
KW - Robotische Schmelzanlage
KW - Ontologie
KW - Simulation
PY - 2023
AN - OPUS4-60377
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Qualitätsüberwachung durch das KorroPad®-Verfahren
N2 - Am Beispiel des KorroPad®-Verfahrens wird ein Ergebnis des H2Mare Teilprojektes "TransferWind" vorgestellt. Im Rahmen des Vorhabens konnte für das Verfahren die DIN 50024:2025-07 erstellt und verabschiedet werden. Das Prüfverfahren ermöglicht es, die Barrierefunktion der Passivschicht auf nichtrostenden Stählen einfach und schnell, direkt durch die Verarbeiter zu prüfen und somit die werkstoffgerechte Verarbeitung sicherzustellen. Das Verfahren liefert ein optisches Prüfergebnis, ist zerstörungsfrei und ermöglicht eine direkte Intervention durch den Verarbeiter bei einer unvollständigen Ausbildung der Passivschicht. Damit kann es helfen spätere Korrosionserscheinungen an Bauteilen und Komponenten aus nichtrostenden Stählen zu vermeiden. Erforderliche Nacharbeiten wären insbesondere bei Offshore -Prozessanlagen mit erheblichen Kosten verbunden.
T2 - Verbundtreffen PtX-Wind / Transferwind
CY - Bremerhaven, Germany
DA - 09.07.2025
KW - Nichtrostender Stahl
KW - Passivität
KW - KorroPad
KW - Normung
PY - 2025
AN - OPUS4-63745
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eggert, Lara
T1 - Korrosivitätsbestimmungen an Offshoreanlagen
N2 - Im Rahmen des Teilprojektes PtX-Wind wurden verschiedene küstennahe sowie offshore Standorte beprobt, um die tatsächliche Korrosivität der Atmosphären zu bestimmen. Mit Offshore Auslagerungsversuchen auf einer Technikplattform (freibewitterter und überdachter Bereich) und an Windenergieanlagen (Außen- und Innenbereich), sollten Daten zur Korrosivität ermittelt werden. Diese stellen eine Grundlage für die dauerhafte und gleichzeitige wirtschaftliche Auslegung des Korrosionsschutzes für Offshore-Prozessanlagen dar. Für Offshore-Windkraftanlagen wird auf Grundlage der abgeschätzten Atmosphäre nach DIN ISO 9223 immer einer Korrosivitätskategorie C5/CX angenommen, was einen entsprechenden Aufwand für den Korrosionsschutz nach sich zieht.
Bei den vorliegenden Untersuchungen zeigte sich, dass für Stahl ab einer Höhe von ca. 40 m über der Meeresoberfläche nur eine Korrosivitätskategorie von C3 bis C4 ermittelt wurde. Dies ist vergleichbar mit Standorten an küstennahen Bereichen bzw. Inseln, bei denen die Kategorie C3 vorliegt.
Im teilklimatisierten Inneren des Turmes liegt die Korrosivitätskategorie nur bei C2. Die Korrosivitätskategorie C2 wurde aber auch für das nicht klimatisierte Air Transition Deck festgestellt. Auf Grundlage dieser Informationen kann die Auslegung des Korrosionsschutzes sowohl für Außenkomponenten als auch für Anlagenkomponenten in klimatisierten Containern abgeleitet werden.
Für alle anderen küstennahen Standorten lag die ermittelte Korrosivität für Zink und Aluminium maximal bei C3. Für Kupfer wurden die höchsten Korrosionsraten mit C4 bis C5 ermittelt, was etwa bei der Auslegung des Korrosionsschutzes elektronischer Bauteile im Außenbereich entsprechend Beachtung finden muss.
Neben den Korrosivitätsinformationen liefern die Auslagerungsversuche auch Informationen über die Performance typischer Konstruktionsmaterialien im Offshore Bereich, wie etwa nichtrostender Stähle sowie ausgewählter Korrosionsschutzmaßnahmen. Der Beitrag stellt ausgewählte Ergebnisse der Auslagerungskampagnen vor.
T2 - H2Mare-Verbundprojekttreffen PtX-Wind & TransferWind
CY - Bremerhaven, Germany
DA - 09.07.2025
KW - Atmosphärische Korrosion
KW - Standardproben
KW - Offshore
PY - 2025
AN - OPUS4-63767
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eggert, Lara
T1 - Möglichkeiten im Meerwasserlabor
N2 - Das Meerwasserlabor am Eidersperrwerk wurde vorgestellt. Dabei lag der Fokus auf die elektrochemischen Versuchsmöglichkeiten, Monitoring von Versuchsparametern, atmosphärische Korrosion und der Bewuchs an getauchten Prüfkörpern.
T2 - H2Mare-Verbundprojekttreffen PtX-Wind & TransferWind
CY - Bremerhaven, Germany
DA - 09.07.2025
KW - Meerwasserlabor
KW - Maritime Korrosion
PY - 2025
AN - OPUS4-63766
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
T1 - The contribution of the Platform MaterialDigital (PMD) in building up a Materials Data Space - Application to glass design and manufacturing
N2 - Suitable material solutions are of key importance in designing and producing components for engineering systems – either for functional or structural applications. Materials data are generated, transferred, and introduced at each step along the complete life cycle of a component. A reliable materials data space is therefore crucial in the digital transformation of an industrial branch.
A great challenge in establishing a materials data space lies in the complexity and diversity of materials science and engineering. It must be able to handle data from different knowledge areas over several magnitudes of length scale.
The Platform MaterialDigital (PMD) is expected to network a large number of repositories of materials data, allowing the direct contact of different stakeholders as materials producers, testing labs, designers and end users. Following the FAIR principles, it will promote the semantic interoperability across the frontiers of materials classes. In the frame of a large joint initiative, PMD
works intensively together with currently near 20 research consortia in promoting this exchange (www.material-digital.de).
In this presentation we will describe the status of our Platform MaterialDigital. We will also present in more detail the activities of GlasDigital, one of the joint projects mentioned above dealing with the digitalization of glass design and manufacturing.
(https://www.bam.de/Content/EN/Projects/GlasDigital/glasdigital.html)
T2 - Onto Commons Workshop
CY - Berlin, Germany
DA - 04.04.2023
KW - Ontology
KW - Data space
PY - 2023
AN - OPUS4-58732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - GlasDigital: Data-driven workflow for accelerated glass development
N2 - Glasses stand out by their wide and continuously tunable chemical composition and large variety of unique shaping techniques making them a key component of modern high technologies. Glass development, however, is still often too cost-, time- and energy-intensive. The use of robotic melting systems embedded in an ontology-based digital infrastructure might overcome these problems. As part of the German research initiative MaterialDigital [1], the joint project GlasDigital took first steps in this direction combining all main components required for accelerated data driven glass development. For this purpose, a robotic high throughput glass melting system was equipped with inline sensors for process monitoring, machine learning (ML)-based adaptive algorithms for process monitoring and optimization, novel tools for high throughput glass analysis and ML-based algorithms for glass design, including data mining as well as property and process modelling. The talk gives an overview how these tools are interconnected and illustrates their usability.
T2 - 27th International Congress on Glass 2025
CY - Kolkata, India
DA - 20.01.2025
KW - Materials digitalisation
PY - 2025
AN - OPUS4-63820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - Internal friction and energy dissipation during crack propagation in silicate glasses
N2 - To obtain a deeper insight into the nature of energy dissipation during crack propagation, the internal friction of 13 borosilicate, aluminosilicate, soda-lime, and lead-containing glasses, for which inert crack growth data are available in the literature, was measured using dynamic mechanical thermal analysis. For asymmetrically bent glass beams, the loss tangent tanδ was determined between 0.2 and 50 Hz at temperatures between 273 K and the glass transition temperature Tg. It was found that the area under the tanδ vs. T/Tg curve correlates with the crack growth exponent, n, in the empirical v ~ KIn relation between crack growth velocity, v, and stress intensity, KI. This correlation was most distinct for T/Tg < 0.3, still clear for T/Tg < 0.5, but not found for T/Tg > 0.8. The observed results indicate that n correlates with the degree of energy dissipation of relaxation phenomena below Tg.
T2 - 27th International Congress on Glass 2025
CY - Kolkata, India
DA - 20.01.2025
KW - Internal friction
KW - Energy dissipation
KW - Crack propagation
KW - Silicate glasses
PY - 2025
AN - OPUS4-63819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dávila, Josué
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Parameter development for Laser Powder Bed Fusion of nickel-based Haynes 282 using diverse density determination methods
N2 - To manufacture functional components using laser powder bed fusion (PBF-LB/M), the execution of a parameter development with the specific material and machine is an indispensable step. Typically, in the search for the optimal parameter set, the volumetric energy density (VED) used to melt the material serves as an adjustment variable, while the resulting part density as the target parameter. Although this approach effectively reduces the process parameters search-space, additional criteria concerning part quality should be considered in the development. This paper introduces a systematic parameter selection approach, refining the characterization process for processing the nickel-based superalloy Haynes® 282®. The presented strategy not only incorporates the density as target condition but also considers the surface quality and dimensional accuracy of the manufactured samples, crucial for near-net-shape manufacturing. Additionally, three porosity measurement methods (Archimedes method, microscopy, gaspycnometry) for AM metal parts are compared, and their validity for this purpose is discussed.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Additive Manufacturing
KW - Laser powder bed fusion (PBF-LB/M)
KW - Archimedes principle
KW - Parameter development
KW - Gaspycnometry
KW - Density determination method
KW - Density optimization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624417
VL - 124
SP - 93
EP - 97
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-62441
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Wiehle, Philipp
T1 - Einfluss der Feuchtigkeit auf das Tragverhalten von Lehmmauerwerk
N2 - Im Mittelpunkt der vorliegenden Arbeit steht der Einfluss der Feuchte auf die mechanischen Eigenschaften von Lehmmauerwerk. Der Wissensstand zum feuchteabhängigen Tragverhalten von Lehm(mauerwerk) ist bisher lückenhaft, sodass keine explizite Berücksichtigung der Bauteilfeuchte bei der Bemessung tragender Konstruktionen erfolgt. Aktuelle und verlässliche Daten zum Einfluss der Feuchte auf die mechanischen Kenngrößen moderner Lehmbaustoffe fehlen bisher ebenso wie Messwerte in Bezug auf die Bauteilfeuchte unter natürlichen Klimabedingungen. Deswegen wurden im Rahmen dieser Arbeit umfangreiche Untersuchungen zum mechanischen und hygrothermischen Verhalten von Lehmmauerwerk durchgeführt.
Die experimentellen Untersuchungen bestehen im Wesentlichen aus Druckversuchen an Lehmsteinen, -mörteln, kleinformatigen Lehmmauerwerksprobekörpern und geschosshohen Lehmmauerwerkswänden. Um das Feuchteverhalten beschreiben zu können, fanden außerdem erstmalig magnetresonanzspektroskopische Messungen an Lehmsteinen statt und es wurden die tatsächlich auftretenden Feuchtegehalte an einer Lehmmauerwerkswand unter natürlichen Klimabedingungen in Form von Langezeitmessungen ermittelt.
Es konnte festgestellt werden, dass ein linearer Zusammenhang zwischen Druckfestigkeit und relativer Luftfeuchte besteht, wobei sich die Druckfestigkeit umgekehrt proportional zur relativen Luftfeuchte verhält. Je Prozent Steigerung der relativen Luftfeuchte kommt es zur Abnahme von einem Prozent der Druckfestigkeit. Gleiches gilt für das Elastizitätsmodul. Weiterhin konnte auf Basis der feuchtetechnischen Untersuchungen ein numerisches Modell zur Berechnung des instationären hygrothermischen Verhaltens für Lehmbaustoffe kalibriert werden. Anhand dieses Modells gelang es die bemessungsrelevanten Feuchtegehalte unter Berücksichtigung des instationären hygrothermischen Verhaltens realitätsnah zu berechnen. Die maximalen Feuchtegehalte im Lehmmauerwerk konnten somit in Form einer Parameterstudie in Abhängigkeit des Anwendungsfalls ermittelt werden, wodurch eine explizite Berücksichtigung des Feuchtegehaltes bei der Bemessung ermöglicht wurde. Die Verknüpfung der Erkenntnisse aus den mechanischen und hygrothermischen Untersuchungen dieser Arbeit bildet die Grundlage für das Bemessungskonzept der im Juni 2023 veröffentlichten DIN 18940: Tagendes Lehmsteinmauerwerk.
KW - NMR
KW - Lehm
KW - Mauerwerk
KW - Druckfestigkeit
KW - Feuchtigkeit
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637794
DO - https://doi.org/10.14279/depositonce-20800
SP - 1
EP - 114
CY - Berlin
AN - OPUS4-63779
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiehle, Philipp
A1 - Baier, Johanna
A1 - Thiele, Marc
T1 - Structural Design of Earth Masonry in Accordance with Eurocode 6 – Considering Moisture Content and E/fk Ratio
N2 - The load‐bearing behaviour of earth masonry is similar to conventional masonry, with two key differences: compressive strength and Young's modulus are dependent on moisture content, and the ratio between Young's modulus and characteristic compressive strength (E/fk) is significantly lower. The current design concept according to the Lehmbau Regeln does not explicitly address these factors, relying instead on a general safety margin, leading to an underestimation of the load‐bearing capacity of modern earth masonry.Compression tests on small‐scale masonry specimens and storey‐high walls revealed that compressive strength and Young's modulus decrease inversely proportional to the increase in relative humidity. Additionally, it was found that conventional masonry design guidelines overestimate the buckling resistance of earth masonry due to its low E/fk ratio of ∼440. However, this ratio remains independent of moisture content, simplifying structural design, as the load‐bearing capacity is only influenced by wall slenderness.The study's findings form the foundation for the newly published German design standard DIN 18940, which explicitly considers moisture content through service classes with moisture factors and addresses the low E/fk ratio with a bilinear adaptation of the reduction factor considering the slenderness. Along with the introduction of the semi‐probabilistic design concept and rigid‐plastic determination of cross‐sectional load‐bearing capacity, modern earth masonry can now be applied in buildings up to four storeys.
T2 - Earth Builder Summit
CY - Biberach, Germany
DA - 06.03.2025
KW - Service class
KW - Earth masonry
KW - Structural design
KW - Moisture
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637803
DO - https://doi.org/10.1002/cepa.3287
SN - 2509-7075
VL - 8
IS - 1
SP - 9
EP - 21
PB - Ernst & Sohn GmbH
AN - OPUS4-63780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Busch, Richard
T1 - Surface Initiated Structure Formation in Glass Ceramics
N2 - A summery of previous research regarding surface crystallization is given as well as results regarding thecurrent DFG project are presented.
T2 - XRM Workshop
CY - Halle, Germany
DA - 03.03.2020
KW - Glass
KW - Surface
KW - XRM
PY - 2020
AN - OPUS4-51337
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Bedingungen für den schadensfreien Einsatz von nichtrostenden Stählen
N2 - Unter Passivität versteht man den Korrosionsschutz durch dünne, festhaftende Schichten aus Korrosionsprodukten. Für den schadensfreien Einsatz nichtrostender Stähle ergeben sich daraus zwei grundsätzliche Anforderungen.
Erstens muss sich die Passivschicht vollständig ausbilden können. Dabei sind die Oberflächenausführung, die mechanische Bearbeitung, die Elementverteilung, Ausscheidungen, die Wärmeeinbringung z.B. bei der schweißtechnischen Verarbeitung, Anlauffarben, sowie die chemische Nachbehandlung bzw. Konditionierung der Oberflächen von großer Bedeutung. Zweitens muss die Repassivierung von Defektstellen unter den Einsatzbedingungen möglich sein. Für das Repassivierungsvermögen sind die Legierungszusammensetzung, mögliche kritische Betriebszustände, prozessbedingte Besonderheiten, wie etwa Stagnationsbedingungen und Reinigungsprozesse von Bedeutung.
T2 - Nichtrostende Stähle - Eigenschaften und Anwendungen
CY - Dusseldorf, Germany
DA - 27.05.2025
KW - Passivität
KW - Korrosion
KW - Dauerhaftigkeit
KW - Schadensursachen
PY - 2025
AN - OPUS4-63242
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reinsch, Stefan
T1 - Orientierte Oberflächenkristallisation in Gläsern
N2 - Bislang wird das Phänomen der orientierten Oberflächenkristallisation kontrovers diskutiert und entsprechende Studien beschränken sich auf nur wenige Gläser. Für Silikatgläser haben wir eine gute Korrelation zwischen der berechneten Oberflächenenergie von Kristallflächen und der orientierten Oberflächenkeimbildung gefunden. Die Oberflächenenergien wurden unter der Annahme abgeschätzt, dass die Kristalloberflächen bei der Keimbildung den Kristallebenen mit minimaler Energie entsprechen, denen ein Riss beim Bruch folgt. Dieses Konzept wurde am Institut für Physik in Rennes erfolgreich bei der Berechnung der Bruchflächenenergien von Gläsern angewandt. Mehrere orientierte Keimbildungsphänomene lassen sich dadurch erklären, dass man annimmt, dass Kristalloberflächen mit hoher Energie dazu neigen, von der Schmelze benetzt zu werden. Dies minimiert die gesamte Grenzflächenenergie des Keims. Darüber hinaus werden wir die Entwicklung der Mikrostruktur beim weiteren Kristallwachstum und ihre Auswirkungen auf die bevorzugte Kristallorientierung diskutieren.
T2 - 21. Treffen des DGG-DKG Arbeitskreises „Glasig-kristalline Multifunktionswerkstoffe“
CY - Mainz, Germany
DA - 22.02.2024
KW - Oberflächenkeimbildung
KW - Kristallorientierung
KW - Grenzflächenenergie
PY - 2024
AN - OPUS4-60237
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Abschlussbericht zum FGS Vorhaben "Gefügeveränderungen bei trockener Grobbearbeitung"
N2 - Der Vortrag stellt die Ergebnisse des Forschungsvorhabens zum Thema Gefügeveränderungen bei trockener Grobbearbeitung vor. Ziel des Vorhabens war die Identifizierung und Quantifizierung möglicher mechanisch- oder thermomechanisch-bedingter Gefügeveränderungen nach trockener Oberflächenbearbeitung. Es wurden opfische und metallografische Untersuchungen sowie Härtemessungen und elektrochemische Korrosionsuntersuchungen durchgeführt.
T2 - Jahrestagung der Foschungsgemeinschaft Schleiftechnik e.V
CY - Würzburg, Germany
DA - 26.03.2025
KW - Stahl
KW - Trockene Schleifbearbeitung
KW - Metallografie
KW - Mikrohärte
KW - Korrosion
PY - 2025
AN - OPUS4-62796
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quosdorf, Heike
T1 - A Digital Object Identifier for Additively Manufactured Parts as Open Source Software Package
N2 - A method to uniquely identify samples without printed or handwritten labels is an advantage not just for additively manufactured parts. To kickstart industry use cases it is important to provide a ready made implementation kit. Following an open science and open source software approach Germanys Federal Institute for Materials Research and Testing BAM seeks to promote digital solutions of ongoing Research projects. With this software package a novel method based on microstructural features as identifiers DOI4AM (digital object identifier for additively manufactured parts will be explained alongside its implementation as open source Python software package.
The digital object identifier (DOI) links product data clearly and forgery proof with real components. Its implementation helps to identify and securely authenticate additively manufactured components during its product life cycle by using characteristic microstructure features just like a fingerprint. To calculate the DOI fingerprint, a few preprocessing steps need to be performed to detect the uniquely distributed microstructure features that occur during the 3D printing process. A go through guide show s the preprocessing steps that include computer tomography (CT) image capturing, feature segmentation and data distribution via CSV files. While all steps can be followed along in a Jupyter notebook with sample data, the software package includes functions to create and compare fingerprints, as well, as an application programming interface (API) for integration in existing software platforms.
A quick showcase of our industry partners implementation of the algorithm as containerized micro service in their digital product passport (DPP) web solution PASS X proves the first successful technology transfer of this project.
T2 - MSE Research Data Forum 2025
CY - Siegburg, Germany
DA - 08.07.2025
KW - Open Science
KW - Authentication
KW - Unique identification
KW - Digital fingerprint
KW - X-ray Computed Tomography
KW - Additive manufacturing
KW - Open Source Software
PY - 2025
AN - OPUS4-63904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Characteristics of environmental stress cracking of PE-HD induced by biodiesel and diesel fuels
N2 - In the context of the increasing effect of carbon dioxide emissions on the global climate biodiesel produced from renewable sources has emerged as a promising contender replacing fossil fuels, especially in long-range transport vehicles, using existing engines and infrastructure.
High-density polyethylene is one of the prevailing materials for pipe and container applications for storage and transport of such fuels, both, from fossil and renewable resources. The contact with the respective fuels raises questions concerning material compatibility as biodiesel exhibits significant differences compared to conventional diesel fuel affecting its sorption and plasticization behavior in polyethylene. In this study, its behavior with respect to environmental stress cracking, considered one of the most frequent damage mechanisms leading to failure of polymer parts and packaging, was evaluated using the well-established Full Notch Creep Test. This
approach allows for a detailed fracture surface analysis using imaging techniques, such as optical and laser scanning microscopy, as well as infrared spectroscopy. Comparing the environmental stress cracking behavior in standard surfactant solutions with that in biodiesel and diesel, respective crack propagation rates, showing different levels of acceleration, were determined and details of the underlying mechanisms could be revealed.
Furthermore, the specific infrared absorption of the biodiesel’s ester functionality allows its semi-quantitative determination on the fracture surface of the tested specimens after failure. Thus, a preferred uptake of sorptive fluids in the fracture zone due to local morphological changes of the polyethylene could be directly evidenced by infrared spectroscopy.
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Confocal laser scanning microscopy (LSM)
KW - Biodiesel
KW - Diesel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608591
DO - https://doi.org/10.1016/j.polymertesting.2024.108547
SN - 0142-9418
VL - 138
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-60859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stühler, Merlin R.
A1 - Makki, Hesam
A1 - Silbernagl, Dorothee
A1 - Dimde, Mathias
A1 - Ludwig, Kai
A1 - Tegner, Bengt E.
A1 - Greve, Christopher
A1 - Rausch, Konstantin
A1 - Herzig, Eva M.
A1 - Köhler, Anna
A1 - Plajer, Alex J.
T1 - Flexibility and Dynamicity Enhances and Controls Supramolecular Self-Assembly of Zinc(II) Metallogels
N2 - Supramolecular self-assembly of stacked architectures is typically achieved through hydrogen bonding or π–π interactions between monomers constructed from stable and inert bonds. In contrast, coordinative interactions of early metals promise distinct self-assembly behaviour due to more flexible bonding geometries and a wider range of stabilities and exchange kinetics. In this report we demonstrate that tailoring the flexible coordination sphere of Zinc(II) complexes via subtle ligand modification promotes not only one but also three-dimensional self-assembly both thermodynamically and kinetically into higher-order fibrous morphologies, the latter being elucidated by electron tomography. As a result, coordination chemistry can be translated into both nanoscopic (fibre stiffness) and macroscopic (thermal gel stability) material properties. Utilizing dynamicity enables gelation via subcomponent self-assembly, constructing the supramolecular polymer network simultaneously with the monomer. Furthermore, coordinative dis- and reassembly via metal-ligand exchange reactions involving the first and second coordination spheres allows for control over gelation and emission of the system. Our report links concepts in supramolecular self-assembly and coordination chemistry by leveraging the unique bonding interactions that cannot be achieved for traditional monomers, promising applications in stimuli-responsive optoelectronics.
KW - Nanomaterial
KW - AFM
KW - Organometallic
KW - Gel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634221
DO - https://doi.org/10.1002/adfm.202507793
SN - 1616-301X
SP - 1
EP - 10
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-63422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thuy, Maximilian
A1 - Pedragosa-Rincon, M.
A1 - Niebergall, Ute
A1 - Oehler, H.
A1 - Alig, I.
A1 - Böhning, Martin
T1 - Environmental Stress Cracking of High-Density Polyethylene Applying Linear Elastic Fracture Mechanics
N2 - The crack propagation rate of environmental stress cracking was studied on high-density polyethylene compact tension specimens under static loading. Selected environmental liquids are distilled water, 2 wt% aqueous Arkopal N100 solution, and two model liquid mixtures, one based on solvents and one on detergents, representing stress cracking test liquids for commercial crop protection products. The different surface tensions and solubilities, which affect the energetic facilitation of void nucleation and craze development, are studied. Crack growth in surface-active media is strongly accelerated as the solvents induce plasticization, followed by strong blunting significantly retarding both crack initiation and crack propagation. The crack propagation rate for static load as a function of the stress intensity factor within all environments is found to follow the Paris–Erdogan law. Scanning electron micrographs of the fracture surface highlight more pronounced structures with both extensive degrees of plasticization and reduced crack propagation rate, addressing the distinct creep behavior of fibrils. Additionally, the limitations of linear elastic fracture mechanisms for visco-elastic polymers exposed to environmental liquids are discussed.
KW - Crack propagation
KW - Environmental stress cracking
KW - Fracture toughness
KW - Crop protection products
KW - High-density polyethylene
KW - Craze–crack mechanism
KW - Linear elastic fracture mechanics
KW - Stress intensity factor
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550476
DO - https://doi.org/10.3390/polym14122415
SN - 2073-4360
VL - 14
IS - 12
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-55047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erdmann, Maren
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Evaluation of UV-induced embrittlement of PE-HD by Charpy impact test
N2 - The impact fracture behavior of two common high-density polyethylene grades for container applications were intensively studied by the instrumented Charpy impact test after well-defined exposure to UV-irradiation. Individual stages of the impact event, such as crack initiation and crack propagation energy as well as maximum impact load, were investigated from the recorded load–deflection curves. UV-induced material property changes were further investigated by infrared spectroscopy, differential scanning calorimetry, and dynamic-mechanical analysis as well as density measurements. Based on the results of the Charpy impact test, three indicators were identified to describe the extend of photooxidation on high-density polyethylene: (a) a reduced Charpy impact strength—at least to half of its initial value for a distinctly brittle impact fracture, (b) a marked decrease in the crack propagation contribution to the impact strength, and (c) an increase of the brittle features of the fracture surface.
KW - Degradation
KW - Mechanical properties
KW - Packaging
KW - Polyolefins
KW - Polyethylene
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509130
DO - https://doi.org/10.1002/APP.49069
SN - 0021-8995
VL - 137
IS - 36
SP - 49069
PB - Wiley
AN - OPUS4-50913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Niebergall, Ute
A1 - Marschall, Niklas
A1 - Alig, I.
A1 - Böhning, Martin
T1 - A phenomenological criterion for an optical assessment of PE-HD fracture surfaces obtained from FNCT
N2 - The full-notch creep test (FNCT) is a common test method to evaluate the environmental stress cracking (ESC) behavior of high-density polyethylene (PE-HD), e.g. for container materials. The test procedure as specified in ISO 16770 provides a comparative measure of the resistance against ESC using the time to failure of PE-HD specimens under constant mechanical load in a well-defined liquid test environment. Since the craze-crack damage mechanism underlying the ESC phenomenon is associated with brittle failure, the occurrence of a predominantly brittle fracture surface is a prerequisite to consider an FNCT measurement as representative for ESC, i.e. a time to failure dominated by craze-crack propagation.
The craze-crack propagation continuously reduces the effective residual cross-sectional area of the specimen during the test, which results in a corresponding increase of the effective mechanical stress. Thus, a transition to ductile shear deformation is inevitable at later stages of the test, leading usually to a pronounced central ligament.
Therefore, an optical evaluation of FNCT fracture surfaces concerning their brittleness is essential. An enhanced imaging analysis of FNCT fracture surfaces enables a detailed assessment of craze-crack Propagation during ESC. In this study, laser scanning microscopy (LSM) was employed to evaluate whether FNCT fracture surfaces are representative with respect to craze-crack propagation and ESC. Based on LSM height data, a phenomenological criterion is proposed to assess the validity of distinct FNCT measurements. This criterion is
supposed to facilitate a quick evaluation of FNCT results in practical routine testing. Its applicability is verified on a sample basis for seven different commercial PE-HD container materials.
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Laser scanning microscopy (LSM)
KW - Fracture surfaces
KW - Optical criterion of brittleness
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521012
DO - https://doi.org/10.1016/j.polymertesting.2020.107002
VL - 94
SP - 107002
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-52101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erxleben, Kjell
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
A1 - Kannengiesser, Thomas
A1 - Kromm, Arne
T1 - In-service and repair welding of pressurized hydrogen pipelines–a review on current challenges and strategies
N2 - Hydrogen is the energy carrier for a sustainable future without fossil fuels. As this requires a reliable transportation infrastructure, the conversion of existing natural gas (NG) grids is an essential part of the worldwide individual national hydrogen strategies, in addition to newly erected pipelines. In view of the known effect of hydrogen embrittlement, the compatibility of the materials already in use (typically low-alloy steels in a wide range of strengths and thicknesses) must be investigated. Initial comprehensive studies on the hydrogen compatibility of pipeline materials indicate that these materials can be used to a certain extent. Nevertheless, the material compatibility for hydrogen service is currently of great importance. However, pipelines require frequent maintenance and repair work. In some cases, it is necessary to carry out welding work on pipelines while they are under pressure, e.g., the well-known tapping of NG grids. This in-service welding brings additional challenges for hydrogen operations in terms of additional hydrogen absorption during welding and material compatibility. The challenge can be roughly divided into two parts: (1) the possible austenitization of the inner piping material exposed to hydrogen, which can lead to additional hydrogen absorption, and (2) the welding itself causes an increased temperature range. Both lead to a significantly increased hydrogen solubility in the respective materials compared to room temperature. In that connection, the knowledge on hot tapping on hydrogen pipelines is rare so far due to the missing service experiences. Fundamental experimental investigations are required to investigate the possible transferability of the state-of-the-art concepts from NG to hydrogen pipeline grids. This is necessary to ensure that no critical material degradation occurs due to the potentially increased hydrogen uptake. For this reason, the paper introduces the state of the art in pipeline hot tapping, encompassing current research projects and their individual solution strategies for the problems that may arise for future hydrogen service. Methods of material testing, their limitations, and possible solutions will be presented and discussed.
KW - In-service
KW - Welding
KW - Hydrogen pipeline
KW - Review
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638847
DO - https://doi.org/10.1007/s40194-025-02127-x
SN - 0043-2288
SP - 1
EP - 24
PB - Springer Science and Business Media LLC
AN - OPUS4-63884
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Thuy, Maximilian
A1 - Brauch, N.
A1 - Niebergall, Ute
A1 - Alig, I.
A1 - Oehler, H.
A1 - Böhning, Martin
T1 - Environmental Stress Cracking of PE-HD Induced by Liquid Test Media Representing Crop Protection Formulations
N2 - Packaging containers for dangerous goods that include aggressive liquids require that any packaging material that is based on high-density polyethylene has a high degree of stability and durability. This work is focused on testing the environmental stress cracking of the high-density polyethylenes used for such containers in contact with crop protection formulations, in particular, two model liquids established in Germany as standardized test media representatives for crop protection formulations containing the various admixtures typical for such products. One of the liquids is water-based and contains mostly surface-active ingredients, while the other is solvent-based and includes some emulsifiers. Originally established for pin impression tests, these model liquids and their individual components were here used for the first time as environmental media in the Full Notch Creep Test, which addresses the resistance against environmental stress cracking. The Full Notch Creep Test was carried out on five high-density polyethylene types with both model liquids, and also on one selected material with its components. The evaluation was focused on the fracture surface structures, which were visualized by a scanning electron microscope and by optical in situ imaging of the notch opening. While the water-based model liquid and its surface-active individual components induced environmental stress cracking with the characteristic pattern for a craze-crack mechanism and so-called brittle fracture on the surface, the solvent-based model liquid and its soluble ingredients exhibited rather ductile failure behavior, caused by the plasticizing effect on the polymer that reduced the yield stress of the high-density polyethylene.
For both cases, fracture surface analysis, together with side views of the crack opening, showed a clear relation between surface pattern, notch deformation (e.g., by blunting), or crack opening due to crack growth with time to failure and the solubility of the liquids in high-density polyethylene.
KW - Environmental stress cracking
KW - Fracture surface
KW - Full Notch Creep Test
KW - Crop protection formulations
KW - High-density polyethylene
PY - 2023
DO - https://doi.org/10.1520/STP164320210095
SP - 317
EP - 341
PB - ASTM International
CY - West Conshohocken, PA (USA)
AN - OPUS4-57459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thuy, Maximilian
T1 - Umgebungsbedingter Spannungsriss: Gefahr für Kunststoffbauteile unter Medieneinfluss
N2 - Polyethylen hoher Dichte (PE-HD) ist ein weit verbreitetes Material für Transportbehälter, die oft für eine längere Nutzungsdauer vorgesehen sind. Insbesondere in diesem Fall können mikroskopische Schäden im Material auch weit unterhalb der Streckgrenze auftreten, die durch eine Spannungskonzentration verursacht werden, deren Ursprung in intrinsischen Materialfehlern oder äußeren Kratzern liegt. Mit fortschreitender Schädigung bilden sich Rissstrukturen, die von verstreckten Fibrillen aufgespannt werden, bis es zum Versagen dieser Fibrillen kommt und sich der Riss ausbreitet. Dieser Schadensmechanismus des langsamen Risswachstums kann durch eine Vielzahl von Umgebungsmedien beschleunigt werden und wird dann als "environmental stress cracking" (ESC) bezeichnet. Eine international normierte Methode zur Validierung der Spannungsrissbeständigkeit von PE-HD Materialien ist der „Full Notch Creep Test“ (FNCT).
Anhand von Bruchflächenauswertungen mittels Rasterelektronenmikroskopie und Laser-Scanning-Mikroskopie, werden die typischen Schädigungsstrukturen des ESC sichtbar. Die fibrillierten Strukturen des ESC auf der Bruchfläche von PE-HD ergeben sich besonders bei oberflächenaktiven wässrigen Umgebungsmedien. In Lösungsmittel-Umgebungsmedien, im Zusammenspiel mit PE-HD, kommt es aufgrund der plastifizierenden Wirkung zur Herabsetzung der Streckspannung und Bruchflächen aus dem FNCT veranschaulichen keine signifikanten Anzeichen des Schädigungsmechanismus ESC.
T2 - 47. VDI-Jahrestagung Schadensanalyse 2021- Mediale und klimatische Beanspruchung von polymeren Produkten
CY - Würzburg, Germany
DA - 06.10.2021
KW - Umgebungsbedingter Spannungsriss
KW - Polyethylen hoher Dichte
KW - Full Notch Creep Test
KW - Lösungsmittel
KW - Oberflächenaktive wässrige Medien
KW - Bruchflächenauswertung
PY - 2021
AN - OPUS4-53665
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Alig, I.
T1 - Charakterisierung von Behälterwerkstoffen aus Polyethylen
N2 - Das langsame Risswachstum (slow crack growth, SCG) sowie der umgebungsbedingte Spannungsriss (environmental stress cracking, ESC) sind relevante Schädigungsmechanismen für teilkristalline Werkstoffe auf Basis von Polyethylen hoher Dichte (PE-HD).
Der Vortrag gibt einerseits einen Überblick über die grundlegenden Struktur-Eigenschafts-Beziehungen in diesem Kontext, andererseits werden auch verschiedene praxisorientierte Prüfverfahren vorgestellt. Letztere wurden in gemeinsamen Forschungsprojekten von BAM und LBF mit dem Schwerpunkt Gefahrgutbehälter bzw. Pflanzenschutzmittel vergleichend untersucht und durch weitergehende Analytik ergänzt.
T2 - 16. Tagung des Arbeitskreises Polymeranalytik Webkonferenz, Fraunhofer LBF und FGK
CY - Online meeting
DA - 22.03.2022
KW - Polyethylen
KW - Full Notch Creep Test
KW - Environmental Stress Cracking
KW - Spannungsriss
PY - 2022
AN - OPUS4-54547
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thuy, Maximilian
T1 - Damage progression of environmental stress cracking affected by manufacturing process-induced microstructural orientation
N2 - Currently, the Full Notch Creep Test (FNCT) [1] method is used by material suppliers and end users in industry for the approval of container and pipe materials based on high-density polyethylene (PE-HD). The resistance to environmental stress cracking (ESC) of the material is evaluated using the time to failure of the specimen in an aqueous solution of a detergent [2, 3]. Usually specimens made of sheets with isotropic material properties, manufactured by hot pressing, are employed in order to obtain intrinsic properties of the material in terms of ESC failure. In contrast, the processes used in manufacturing to form containers and pipes, such as extrusion blow molding or extrusion, impose anisotropic properties to the material. These are mostly due to a microstructural orientation (polymer chains or crystallites) [4]. Furthermore, the different cooling conditions significantly affect the size distribution of crystallites as well as the overall morphology. It is therefore essential to understand the influence of process-induced material characteristics on failure due to ESC.
A large number of studies on material properties as a function of microstructural preferential orientation have already been conducted [5-7]. However, effects on ESC as the major failure mechanism of containers and pipes are still rather unexplored [8, 9]. The most important factor is whether primarily intramolecular high-strength covalent bonds or the substantially weaker intermolecular van der Waals forces are predominantly loaded.
In addition to the widely established classification by time to failure, the strain or crack opening displacement (COD) provides valuable information about the evolution and progression of damage as a function of time [10, 11]. Optical strain measurement using digital image correlation allows the differences in COD for isotropic and different angles of orientation of anisotropic specimens to be discussed. Also, a post-fracture surface analysis provides clarification on the craze-crack mechanism of the ESC. These different ESC-related properties of extruded and hot-pressed specimens have been investigated at different environmental medium temperatures and different initial stresses to provide a broad characterization of the fracture behavior of PE-HD.
T2 - 36th International Conference of the Polymer Processing Society
CY - Montreal, Canada
DA - 26.09.2021
KW - Environmental stress cracking
KW - High-density polyethylene
KW - Fracture behavior
KW - Microstructural orientation
PY - 2021
AN - OPUS4-53400
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Böhning, Martin
T1 - Modernizing FNCT data handling in polymer labs: Towards efficient management
N2 - A streamlined Python-based workflow for transforming Full-Notch Creep Test (FNCT) data into organized, machine-actionable formats is presented. The workflow automates the conversion of raw FNCT data from classic CSV and Excel files into structured outputs that facilitate future semantic integration. Emphasizing practical data handling, the approach includes automation scripts for efficient data extraction, transformation, and storage, which culminate in well-ordered files. This transformation paves the way for potential semantic data integration and facilitates access for users with varying levels of digital experience to enhanced data management in polymer research and testing.
KW - PE-HD
KW - Full-Notch Creep Test (FNCT)
KW - Environmental Stress Cracking (ESC)
KW - Data Interoperability
KW - FAIR Data
KW - Semantic Data
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637826
DO - https://doi.org/10.1016/j.commatsci.2025.114085
SN - 0927-0256
VL - 259
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-63782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Iskhakov, Tagir
T1 - Computational modeling of temperature compensation for eddy current testing during PBF-LB/M
N2 - The laser powder bed fusion (PBF-LB/M) process enables the production of highly customized parts with complex geometries. However, the mechanical performance of additively manufactured parts can be compromised by the presence of microstructural inhomogeneities. To address this issue, a reliable process monitoring tool is required to detect these flaws and improve part quality. Eddy current testing presents a promising solution for such monitoring. However, the high temperature gradients within the manufactured specimen affect the electrical conductivity of the material, which, in turn, influences the eddy current testing performance. Therefore, accurately predicting the temperature distribution is essential for reliable flaw detection, which is the focus of this work.
In this study, a Finite Element (FE) transient thermal model is developed to predict the temperature field in multipart build jobs. In this model, scan vectors are grouped into clusters based on their timestamps, enabling the homogenization of thermal loads from multiple scan vectors. When a single cluster is used, the thermal load is applied to the entire layer in a single step. Increasing the number of clusters per layer — and thus the number of steps — enhances the accuracy of temperature predictions. This approach allows for optimizing the trade-off between modeling accuracy and computational efficiency. The study evaluates the prediction accuracy required for eddy current testing and investigates the optimal number of clusters (i.e., the adequate level of homogenization) needed to achieve this accuracy. The model predictions are validated through comparison with thermography images and thermocouple measurements. Finally, the concept of eddy current testing with simulation-based temperature compensation is evaluated on specimens with simple geometries.
T2 - SIM-AM 2025
CY - Pavia, Italy
DA - 09.09.2025
KW - Eddy current testing
KW - FEM
KW - 316L
PY - 2025
AN - OPUS4-64121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eggert, Lara
T1 - Possibilities in the seawater laboratory on Germany’s North Sea coast
N2 - The aim of the seawater laboratory is to observe and test corrosion and corrosion protection systems in real seawater in a fully equipped electrochemistry laboratory. The unique selling point is a seawater bypass, which makes it possible to colonize and maintain salt water or brackish water growth (bacteria, algae, krill, shell, fungi, etc.). The annual course of the marine environment can be observed.
Issues like the selection of materials or simulation of corrosion and corrosion protection systems in real seawater can be studied. As an example, the corrosive influence of the real seawater on immersed steel (S355) and a bimetallic cell of S355 and stainless steel (1.4362) is monitored over one year by measuring potentials and cell currents. Experiments were performed to study the possible corrosion accelerating effects like bimetallic and microbiologically influenced corrosion. These can be run under two different conditions to simulate light and dark environments. The results can help to understand enhanced corrosion rates of steel mounted on offshore wind power plant. Moreover, the roof of the seawater laboratory is also an atmospheric exposure site and will be continuously sampled in the coming years.
T2 - EuroCorr 2025
CY - Stavanger, Norway
DA - 07.09.2025
KW - Meerwasserlabor
KW - Maritime Korrosion
KW - Atmosphärische Korrosion
PY - 2025
AN - OPUS4-64128
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Component test for the assessment of in-service welding on/onto pressurized hydrogen pipelines
N2 - Hydrogen is seen as the energy carrier of the future. Therefore a reliable infrastructure to transport hydrogen in a large scale is needed. A so called European hydrogen backbone out of long distance transmission pipelines is planned by European countries to create a hydrogen transport infrastructure. Due to economic reasons this will be achieved by new build pipelines such as repurposed natural Gas (NG) pipelines, converted to hydrogen useage. A general suitability for hydrogen service of low alloyed pipeline steel, as it is used for NG service today, is given. But in case of necessary in-service welding procedures in terms of e.g. hot-tapping and stoppling, the risk of a critical hydrogen uptake into the pipe materials due to much higher temeperatures while welding and the possibility of hydrogen embrittlement (HE) needs to be closely investigated. The presentation gives an overview of the current H2-SuD project, investigating the feasability of in-service welding on future hydrogen pipelines. Therefore, component-like demonstrators were developed to test (I) the additional hydrogen uptake due to in-service welding under hydrogen pressure and (II) to measure the temperature field due to different welding parameters and demonstrator geometries, especially on the inner pipe wall surface. Collected data will be used to validate a numerical simulation of the thermal field and additionally the hydrogen diffusion in the pipeline material.
T2 - Presentation at The University of Manchester
CY - Manchester, United Kingdom
DA - 12.09.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Welding
PY - 2025
AN - OPUS4-64129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - Applied and Technical Mineralogy:� high-throughput automated platform for in-situ monitoring of CaSO4 formation
N2 - In this project we investigate nucleation pathways by utilizing synchrotron-XRD and running a case-study on calcium sulfate and its polymorphs. To accomplish this, we developed a modular automation setup for reactions in solution to run synthesis and control reaction conditions. So far we successfully characterized the recycling process of gypsum (CaSO4*2H2O) and are now investigating the formation of anhydrite (CaSO4*0H2O) as well as possible applications for the automation setup and analysis.
T2 - Geo4Göttingen 2025
CY - Göttingen, Germany
DA - 14.09.2025
KW - Recycling
KW - Gypsum
KW - Synchrotron-X-ray-diffraction
KW - Raman-spectroscopy
KW - Automation
PY - 2025
AN - OPUS4-64139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Semantic Technologies for Digital Transformation in Materials Science: From PMDco to Prototypical Applications
N2 - The digital transformation of Materials Science and Engineering (MSE) is accelerating the adoption of structured, interoperable, and FAIR data practices, in particular with respect to an advanced research data management. Semantic technologies play a pivotal role in this transformation, as the enable the integration, contextualization, and automation of diverse data sources across experimental, computational, and simulation domains. Central to these efforts is the Platform MaterialDigital Core Ontology (PMDco), now in version 3.0, which provides a robust mid-level semantic framework tailored for MSE. PMDco bridges abstract high-level ontologies, such as the Basic Formal Ontology (BFO) standardized in ISO/IEC 21838-2, with domain-specific terminologies to ensure consistency and interoperability across applications.
This presentation explores the application of PMDco and its integration into workflows within the Platform MaterialDigital (PMD) initiative. Through its deployment in electronic laboratory notebooks (ELNs), PMDco enables semantic representation of experimental data, such as tensile test results compliant with ISO 6892-1:2019-11, transforming them into machine-actionable knowledge graphs. Prototypical implementations demonstrate how semantic technologies enhance laboratory processes, improve data reuse, and streamline documentation which offers opportunities for automation and education.
Further extending its versatility, PMDco serves as a linking point for semantically representing simulation data, enabling comprehensive integration of experimental and computational datasets. This creates structured data spaces that support advanced digital workflows. Beyond PMDco, the presentation highlights the design of graph patterns and semantic shapes, showcasing generalizable methods for managing diverse data in MSE being based on data structuring and formatting.
By presenting best practices in ontology development, data acquisition, and knowledge graph generation, this talk underscores the transformative potential of semantic technologies in MSE. It offers a forward-looking perspective on the role of structured data spaces as a driver for innovation, ensuring that materials science continues to advance through rigorous, interoperable, and automated digital methodologies.
T2 - FEMS Euromat 2025
CY - Granada, Spanien
DA - 14.09.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
KW - PMD Core Ontology
KW - Graph Patterns
PY - 2025
AN - OPUS4-64165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Numerical simulation of weld heat input effect on microstructure and hydrogen diffusion in thick-walled S690 submerged arc welded joints
N2 - High-strength, low-alloy (HLSA) steels such as S690 are an attractive option for heavy industries such as offshore wind turbines and peripheral equipment due to their combination of excellent mechanical properties and weldability. The construction of these thick-walled structures requires highly efficient welding processes such as submerged arc welding (SAW). However, SAW presents challenges related to delayed hydrogen assisted cold cracking (HACC). Despite its importance, the effect of different diffusion coefficients on the cold cracking susceptibility of different microstructures within SAW-welded S690 steels is not fully understood. For this reason, the present study focuses on comparing the cold cracking susceptibility of thermomechanically rolled (TM) or quenched and tempered (QL) variants of S690 steel. SAW was performed on specimens of both steel grades to produce weldments consisting of weld metal, heat-affected zone (HAZ), and base metal. Electrochemical hydrogen permeation tests (ISO 17081) were performed to determine the microstructure specific coefficients. Using the obtained coefficients, a numerical model was developed to identify the time- and microstructure-dependent local hydrogen diffusion and its influence on the distribution within the welds. The results showed that the TM grade exhibited slightly accelerated hydrogen diffusion compared to the QL grade, which is beneficial for hydrogen reduction and increases the HACC resistance. However, the further simulations with different ply sequences showed that the welding heat input (i.e. welding ply sequence) had a significantly higher effect on hydrogen accumulation. Specifically, increased welding heat input and increased thicknesses decrease hydrogen diffusivity. For this reason, microstructure-specific hydrogen diffusion played a minor role in thick-layer SAW joints compared to the need to control the welding parameters (layer sequence, individual layer thickness, welding heat input).
T2 - FEMS Euromat 2025 - 18th European Congress and Exhibition on Advanced Materials and Processes
CY - Granada, Spain
DA - 15.09.2025
KW - Hydrogen assisted cracking
KW - Welding
KW - High strength steels
KW - Numerical simulation
KW - Electrochemical permeation
PY - 2025
AN - OPUS4-64158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Hydrogen trap characterization in 200 and 1,000 bar charged CoCrNi medium entropy alloy compared to steel AISI 316L
N2 - Multiple principal element alloys (MPEAs) represent a new class of metallic materials. MPEAs, such as the CoCrNi medium entropy alloy (MEA), have attracted considerable research attention as potential materials to replace, for example, austenitic steels in high-pressure hydrogen environments. Due to the relatively new alloy concept, studies on the specific hydrogen diffusion and trapping behavior of high-pressure hydrogen-charged CoCrNi MEAs are rare so far. For this reason, a CoCrNi-MEA was investigated and compared to an austenitic stainless steel, AISI 316L. Both materials were subjected to high pressure hydrogen loading for two different pressures: 200 bar and 1,000 bar. After charging, thermal desorption analysis (TDA) was used with three heating rates from 0.125 K/s to 0.500 K/s to clarify the specific hydrogen desorption and trapping behavior. To the best of our knowledge, this study is the first to characterize hydrogen diffusion and trapping in 1,000 bar high-pressure charged CoCrNi. For this purpose, the underlying TDA spectra were analyzed in terms of peak deconvolution into a metallurgically justifiable number of defined peaks. The individual peak temperatures and activation energies “EA” were calculated. The following conclusions can be drawn from the results obtained: (1) Exposure to 200 bar or 1,000 bar leads to an increase in hydrogen absorption, regardless of the material investigated, expressed by a significantly increased desorption rate at 1,000 bar. However, the effusion peaks typically occur only at high temperatures. The (2) TDA showed that a four-peak deconvolution scenario was sufficient to describe the trapping behavior and the "EA" indicated the dominance of irreversible traps. In addition, the average trapping energy is higher than in the 316L. The (3) charge pressure related hydrogen solubility was in the order of: CoCrNi-MEA < 316L for both pressures and (4) charging at 1000 bar results in an average concentration of 49 wt.ppm (CoCrNi-MEA) and > 75 wt.ppm (316L). In summary, the CoCrNi-MEA was characterized by a reduced solubility, but very deep entrapment compared to the 316L. For this reason, further application potentials of the MEA may arise.
T2 - FEMS Euromat 2025 - 18th European Congress and Exhibition on Advanced Materials and Processes
CY - Granada, Spain
DA - 15.09.2025
KW - Medium entropy alloy
KW - Hydrogen
KW - Trapping
KW - Diffusion
KW - High-pressure charging
PY - 2025
AN - OPUS4-64160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Effect of Ti and Nb on hydrogen trapping in welded S690 HSLA steel and effect on delayed cold cracking
N2 - Fine-grain, high-strength, low-alloy (HSLA) structural steels with yield strengths > 600 MPa are now the state of the art in construction applications such as mobile cranes and civil engineering. HSLA grades derive their strength from a combination of specific heat treatment and the underlying chemical composition. In this context, Ti or Nb are essential to obtain a fine-grained microstructure as well as the necessary carbides or nitrides for precipitation strengthening. In this context, the specific effect of Ti or Nb-rich compounds on hydrogen trapping and diffusion is well known for special laboratory cast alloys, but unknown for realistic steel compositions. For this reason, a series of S690Q-based alloys were synthesized, close to a real steel composition, but with well controlled Ti or Nb additions in different amounts. Specimens were obtained from these alloys by electrochemical discharge machining (EDM). The specimens were tested using the well-established electrochemical permeation technique. From the experimental results, the hydrogen diffusion coefficients and the analytical subsurface hydrogen concentration were calculated. In addition, the hydrogen trapping behavior at elevated temperatures was interpreted by thermal desorption analysis (TDA) using different heating rates of hydrogen charged samples. The results showed that in contrast to metallurgically "pure" laboratory cast alloys, realistic chemical compositions were similar in their hydrogen trapping behavior, despite some small differences. All investigated steel grades exhibited shallow and reversible hydrogen trapping, regardless of their chemical composition. Of course, the experiments only allowed the calculation of effective diffusion coefficients and trapping energies, which represent an average of the entire microstructure. Nevertheless, HSLA steels are typically joined by arc welding, which includes the risk of delayed hydrogen assisted cracking. From the point of view of welding practice, however, a more or less identical hydrogen diffusion behavior means that no special "metallurgically specific", justifiable measures need to be considered, despite the well-established processes such as "soaking" or dehydrogenation heat treatment. Of course, a closer look at the heat-affected zone (HAZ) or the weld metal of the specific welds is necessary. However, especially in the case of thick-walled welds, it is assumed that the weld metal and HAZ are similar to the base material due to the multi-layer welding, which results in multiple annealing cycles of the weld metal and HAZ.
T2 - FEMS Euromat 2025 - 18th European Congress and Exhibition on Advanced Materials and Processes
CY - Granada, Spain
DA - 15.09.2025
KW - Hydrogen assisted cracking
KW - HSLA
KW - Diffusion
KW - Electrochemical permeation
PY - 2025
AN - OPUS4-64156
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Component test for the assessment of in-service welding on/onto pressurized hydrogen pipelines
N2 - Hydrogen is the energy carrier of tomorrow and requires a reliable large-scale transport infrastructure. In addition to new pipelines, the conversion of existing natural gas (NG) pipeline grids is an essential part. The transport of hydrogen is fundamentally different from that of NG, as hydrogen can be absorbed into the pipeline material. Given the effects of hydrogen embrittlement, the material compatibility (low alloy steels in a wide range of strengths and thicknesses) must be investigated. However, pipelines e.g. require maintenance or the need for installation of additional outlets with the necessity of welding on/onto the pipelines while they are still in service, i.e. with gas flow under high pressure, such as the well-known "hot tapping". This in-service welding poses challenges for hydrogen operations. The challenge can be roughly divided into the possible austenitization of the inner pipe material exposed to hydrogen, the welding itself, which causes an increased temperature range. Both lead to a significant increase in hydrogen solubility and diffusivity compared to room temperature. In addition, possible surface reactions of the present iron oxides (e.g. magnetite or hematite) with the hot hydrogen should be considered. In this context, the knowledge of hydrogen pipelines is scarce due to the lack of operational experience. Fundamental experimental investigations are required to investigate the transferability from NG to hydrogen pipeline grids. For this reason, the present study presents a specially designed mock-up / demonstrator concept for the realistic assessment of the welding process conditions. The mock-up was designed to allow in-situ temperature measurement during the welding process as well as ex-post sample extraction for quantification of the absorbed hydrogen concentration. For safety reasons, the required volume of pressurized hydrogen was limited by inserting a solid cylinder to ensure a 1 cm thick layer of hydrogen gas. Welding experiments on the DN60 and DN200 pressurized mock-ups showed the possibility of safe welding on or onto pressurized hydrogen pipelines. Indeed, the austenitizing temperature was reached on the inner surface of the pipeline, especially on thinner-walled pipelines, using current welding parameter recommendations. This corresponded to an increased hydrogen uptake in the welded area of several ppm. From this point of view, the suggested component concept is a viable strategy for the screening of several materials and welding parameter combinations under realistic operational conditions.
T2 - FEMS Euromat 2025 - 18th European Congress and Exhibition on Advanced Materials and Processes
CY - Granada, Spain
DA - 15.09.2025
KW - In-service welding
KW - Pipeline
KW - Hydrogen
KW - Component test
PY - 2025
AN - OPUS4-64159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Component-test for determination of welding residual stresses and their effect on stress relief cracking in thick-walled welds
N2 - Controlling the residual stress level during welding of creep-resistant Cr-Mo-V steels is crucial to avoid so called stress relief cracking (SRC) during post weld heat treatment (PWHT) of large-scale components. In the present study, a laboratory scale test specimen (slotted sample with 400 mm width, 400 mm length and 25 mm thickness) was used to simulate thick-walled component welds made of 13CrMoV9-10. The aim was to identify the level and distribution of residual stresses to evaluate the suitability of the specimen for laboratory based SRC testing. High restraint was ensured by the specimen geometry with a narrow welding gap in the center. This gap was filled by multi-layer submerged arc welding. Two specimens were welded with identical parameters and compared in the as-welded state and after PWHT (705 °C for 10 h). Neutron diffraction was used to determine the residual stresses in the weld metal, the heat-affected zone (HAZ) and the base material at different depths longitudinal, transverse, and normal to the welding direction. The experiments were performed on the former instrument E3 of the research reactor BER II of Helmholtz-Zentrum Berlin (HZB), Germany. Complementarily, laboratory X-ray diffraction was applied to characterize the surface residual stresses. In the welded condition, especially in the weld metal and the adjacent HAZ, the longitudinal residual stresses reached values of up to 1,000 MPa to 1,200 MPa due to the increasing strength and hardness of the CrMoV-material during welding. The conducted welding experiments revealed that way higher residual stresses in the welded joint have to anticipated before the PWHT is performed than it was expected in advance. This demonstrated the necessity of suitable component-like welding tests as they must ensure realistic mechanical stiffness (hindered shrinkage of welding joint by slotted self-restraint sample) and heat dissipation conditions (definition of minimum welding joint thickness vs. welding process-specific heat input).
T2 - FEMS Euromat 2025 - 18th European Congress and Exhibition on Advanced Materials and Processes
CY - Granada, Spain
DA - 15.09.2025
KW - Component test
KW - Submerged arc welding
KW - Post weld heat treatment
KW - Residual stresses
KW - Neutron diffraction
PY - 2025
AN - OPUS4-64161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geranmayeh, Ali
T1 - Laser Metal Deposition of NiTi Shape Memory Alloys: Influence of Process Parameters on Thermal Profiles and Part Properties
N2 - Laser Metal Deposition (LMD), a laser powder–directed energy deposition technology (LP-DED), offers unique flexibility for fabricating complex metallic components. Among candidate materials, Nitinol (NiTi) is particularly attractive due to its shape memory and superelastic properties, though its high sensitivity to processing conditions demands precise parameter control. In this work, prealloyed NiTi powder was deposited as single tracks, and process parameters were optimized using a Design of Experiments methodology. A Central Composite Design (CCD) was implemented with laser power, scan speed, and powder feed rate as inputs, while track’s height, width, aspect ratio, and dilution served as optimization responses. To address the strong susceptibility of NiTi to heat accumulation, hatch spacing was further optimized using a geometrically derived formula, enabling the use of maximum spacing while ensuring dense parts with smooth surfaces and minimal waviness. The presented framework establishes a systematic route for parameter optimization in NiTi LMD, offering practical guidelines for balancing densification and surface quality.
T2 - WGF Assistant Seminar
CY - Rechenberg-Bienenmühle, Germany
DA - 10.09.2025
KW - Additive manufacturing
KW - Shape memory alloys
KW - Nitinol
KW - Laser metal deposition
KW - Design of experiments
PY - 2025
AN - OPUS4-64164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fontoura Barroso, Daniel
A1 - Epple, Niklas
A1 - Niederleithinger, Ernst
T1 - A Portable Low-Cost Ultrasound Measurement Device for Concrete Monitoring
N2 - This paper describes a new ultrasonic measuring device called “W-Box”. It was developed based on the requirements of the DFG Forschergruppe (research unit) CoDA for a portable device for monitoring of concrete specimens, models and actual structures using embedded ultrasonic transducers as well as temperature and humidity sensors. The W-Box can send ultrasonic pulses with a variable frequency of 50–100 kHz to one selectable transducer and records signals from up to 75 multiplexed channels with a sample rate of 1 MHz and a resolution of 14 bits. In addition, it measures temperature and humidity with high accuracy, adjustable amplification, restarts automatically after a power failure and can be fully controlled remotely. The measured data are automatically stored locally on-site data quality checks and transferred to remote servers. The comparison of the W-Box with a laboratory setup using commercial devices proves that it is equally reliable and precise, at much lower cost. The W-Box also shows that their measurement capacities, with the used embedded ultrasonic transducers, can reach above 6 m in concrete.
KW - Low-cost
KW - Coda wave interferometry
KW - Ultrasound
KW - IoT
KW - Non-destructive testing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546756
DO - https://doi.org/10.3390/inventions6020036
SN - 2411-5134
VL - 6
IS - 2
SP - 1
EP - 17
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-54675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diewald, F.
A1 - Epple, Niklas
A1 - Kraenkel, T.
A1 - Gehlen, C.
A1 - Niederleithinger, Ernst
T1 - Impact of External Mechanical Loads on Coda Waves in Concrete
N2 - During their life span, concrete structures interact with many kinds of external mechanical loads. Most of these loads are considered in advance and result in reversible deformations. Nevertheless, some of the loads cause irreversible, sometimes unnoticed changes below the macroscopic scale depending on the type and dimension of the impact. As the functionality of concrete structures is often relevant to safety and society, their condition must be known and, therefore, assessed on a regular basis. Out of the spectrum of non-destructive monitoring methods, Coda Wave Interferometry using embedded ultrasonic sensors is one particularly sensitive technique to evaluate changes to heterogeneous media. However, there are various influences on Coda waves in concrete, and the interpretation of their superimposed effect is ambiguous. In this study, we quantify the relations of uniaxial compression and uniaxial tension on Coda waves propagating in normal concrete. We found that both the signal correlation of ultrasonic signals as well as their velocity variation directly reflect the stress change in concrete structures in a laboratory environment. For the linear elastic range up to 30% of the strength, we calculated a velocity variation of −0.97‰/MPa for compression and 0.33%/MPa for tension using linear regression. In addition, these parameters revealed even weak irreversible changes after removal of the load. Furthermore, we show the time-dependent effects of shrinkage and creep on Coda waves by providing the development of the signal parameters over time during half a year together with creep recovery. Our observations showed that time-dependent material changes must be taken into account for any comparison of ultrasonic signals that are far apart in time. The study’s results demonstrate how Coda Wave Interferometry is capable of monitoring stress changes and detecting even small-size microstructural changes. By indicating the stated relations and their separation from further impacts, e.g., temperature and moisture, we anticipate our study to contribute to the qualification of Coda Wave Interferometry for its application as an early-warning system for concrete structures.
KW - Ultrasound
KW - Coda Wave Interferometry (CWI)
KW - Mechanical Load
KW - Microstructure
KW - Concrete
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556878
DO - https://doi.org/10.3390/ma15165482
SN - 1996-1944
VL - 15
IS - 16
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-55687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reinsch, Stefan
T1 - Robot-assisted compositional screening in the System Na2O-Al2O3-B2O3-SiO2
N2 - The system Na2OB2O3SiO2 (NBS) is the basis of many industrial glass applications and therefore one of the most studied systems at all. Glass formation is possible over a wide compositional range, but the system also contains ranges of pronounced phase separation and crystallization tendency. Even small addition of Al2O3can change this behavior essentially. As the Na2OAl2O3B2O3SiO2 (NABS) system is also known as the basis for glasses in strength-relevant applications, the behavior during the transition from the NBS system to the NABS system is of interest. Therefore, some small step melt series in these systems were studied using the robotic glass melting system at the Federal Institute for Materials Research and Testing (BAM, Division Glasses). For these series the small step changes of glass transition temperature, crystallization behavior as well as glass density were studied. Additionally, experimental data were compared with their modeled counterparts.
T2 - 98. Glastechnische Tagung
CY - Goslar, Germany
DA - 26.05.2025
KW - Sodium alumino boro silicate glasses
KW - Glass transition temperature
KW - Density
KW - Robotic melting
PY - 2025
AN - OPUS4-64076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Linden, Anna
T1 - AMVAD - Additive manufacturing for ventricular assist devices
N2 - Some children are born with a univentricular heart, meaning their heart has only one pumping chamber instead of two. To improve circulation, patients often undergo the Fontan procedure, which reroutes blood flow — but this can put stress on other organs. In some cases, ventricular assist devices, or VADs, are used to support the heart’s pumping function. This involves an artificial pump connected directly to the patient's heart via silicone-based cannulas. Unique anatomical conditions introduce special challenges for cannula geometry. Additive manufacturing offers innovative solutions by enabling the production of personalized medical devices. The aim of the project is to develop the manufacturing workflow for the individualized cannula from digital imaging of the patient and customized design to additive manufacturing. Besides technical feasibility, validating the entire process is crucial for regulatory approval. The selection and testing of suitable additive manufacturing processes and biocompatible materials for individualized silicone cannulas, ensuring compliance with quality standards for high-risk medical products, will be presented.
T2 - AMBER Spotlight On: 3D Printing meets Health & Biotech
CY - Berlin, Germany
DA - 16.09.2025
KW - Additive manufacturing
KW - Medical device
KW - Liquid silicone rubber
PY - 2025
AN - OPUS4-64101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - A New Young Network - die junge gfkorr (Das Netzwerk für junge Korrosionisten)
N2 - This invited talk at the Young EFC Meeting (European Federation of Corrosion) was about the new network, founded in Germany in 2023, specialising in corrosion and corrosion protection. The network is called "die junge gfkorr" and has the following aims: (i) Initiation of in-person events with excursions and a networking atmosphere. (ii) Members come from both industry and academia can find similarities in each other's work (iii) Get to know each other and learn from each other, and (iv) Members benefit long-term by using the network throughout their careers and for future collaboration on daily business and research projects.
T2 - Conference EUROCORR 2025, Young EFC Meeting
CY - Stavanger, Norway
DA - 07.09.2025
KW - Coatings
KW - Corrosion
KW - Corrosion Protection
KW - Network
PY - 2025
AN - OPUS4-64102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - My surface at a glance: grazing incidence scattering applications
N2 - Three literature examples are presented to demonstrate the wide range of applications of grazing incidence scattering. These examples concern 1) the determination of the density of a porous film, 2) how orientation of conducting polymers is observed in grazing incidence scattering, and 3) how the three-dimensional order of nanoparticles is reflected in the data. To conclude we show recent data from the MOUSE lab demonstrating the new capability to observe intermolecular distances in thin films using the molybdenum X-ray source.
T2 - Surface Transfer of Pathogens (STOP) - M37 meeting
CY - Turin, Italy
DA - 11.09.2025
KW - Grazing incidence
KW - GISAXS
KW - Applications
PY - 2025
AN - OPUS4-64115
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Clozel, Melanie
A1 - Neumann, Christian
A1 - Thore, Johannes
A1 - Kolbe, Matthias
A1 - Yang, Fan
A1 - Gutowski, Olof
A1 - Dippel, Ann-Christin
A1 - Ruschel, Lucas M.
A1 - Busch, Ralf
A1 - Altenbach, Christoph
A1 - Akuata, Chijioke Kenneth
A1 - Zander, Daniela
A1 - Wilbig, Janka
A1 - Meyer, Andreas
T1 - Microstructure formation during gas flow-assisted additive manufacturing of a metallic glass powder on ground and in microgravity
N2 - We studied bulk metallic glasses produced from gas flow-assisted laser-based powder bed fusion process, which is capable of additive manufacturing metallic parts in microgravity. A Zr-based bulk metallic glass composition Zr₅₉ˏ₃Cu₂₈ˏ₈Al₁₀ˏ₄Nb₁ˏ₅ has been processed on ground and in microgravity in a compact sounding rocket payload MARS-M. Microstructure characterization was performed using electron microscopy and X-ray diffraction computed tomography, which cope with small amounts of sample materials, especially for those fabricated under microgravity conditions. Very similar microstructures and crystalline fractions are observed in sample manufactured on ground and in microgravity, which shows that process parameters of conventional laser powder bed fusion for manufacturing metallic glasses can be transferred to the processes in microgravity. Two different origins of crystallization have been identified in the Zr₅₉ˏ₃Cu₂₈ˏ₈Al₁₀ˏ₄Nb₁ˏ₅ sample. The preferred occurrence of CuZr₂ at the interlayer boundaries is likely a result of recrystallization from the undercooled melt and hence associated with laser scanning strategy. In contrast, the more uniformly distributed Al₃Zr₄ phase is considered to be triggered by the formation of Cu₂Zr₄O. Thus, for the fabrication of fully amorphous builds both on ground and in space, our findings point to higher scanning speeds and lower oxygen contents, while the latter can also be used to tune the crystalline fractions in the sample.
KW - Gas flow-assisted laser-based powder bed fusion
KW - Microgravity
KW - Glass-forming alloys
KW - X-ray diffraction tomography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641253
DO - https://doi.org/10.1007/s40964-025-01275-2
SN - 2363-9512
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
CY - Cham, Switzerland
AN - OPUS4-64125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paskin, Alice
A1 - Couasnon, Thaïs
A1 - Blukis, Roberts
A1 - Perez, Jeffrey Paulo H.
A1 - Reinsch, Stefan
A1 - Roddatis, Vladimir
A1 - Syczewski, Marcin
A1 - Benning, Liane G.
T1 - Temperature-Induced Phase Transitions of Vivianite: In Situ Analysis of a Redox-Driven Crystallization
N2 - We document a solid-state, temperature-dependent (25−700 °C), multistage redox transformation of crystalline ferrous iron phosphate, vivianite (Fe3(PO4)2·8H2O). Under anoxic conditions, vivianite breaks down at T > 250 °C into an anhydrous, amorphous intermediate Fe3(PO4)2 phase, yet the bulk shape and morphology of the starting vivianite crystals were retained. This amorphous intermediate phase remained stable until T > 500 °C, after which a redox-dependent crystallization into two different minerals was observed. Under anoxic conditions, the amorphous ferrous intermediate (Fe3(PO4)2) transformed into the crystalline ferrous phosphate (graftonite, (Fe2+)3(PO4)2), while under oxic conditions it crystallized into a ferric phosphate (rodolicoite, Fe3+PO4). Graftonite formation occurs via an exothermic molar enthalpy (ΔHcryst) of −16.7 ± 0.2 kJ mol−1. Rietveld refinements of the two crystalline endmembers (vivianite and graftonite) revealed a unit cell volume decrease of ∼3.1% during the transformation, which was observed by in situ electron microscopic observations as an overall shrinking of the initial vivianite crystals. Despite volume loss and bubble-like features, the original vivianite shape was preserved, indicating a solid-state pseudomorphic transformation. Ex situ XRD and TEM-EELS analyses confirmed the ferrous-to-ferric oxidation, forming rodolicoite, through changes in the Fe geometry and oxidation state.
KW - Vivianite
KW - Graftonite
KW - Crystallization enthalpy
KW - Ferrous phosphates
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640782
DO - https://doi.org/10.1021/acs.inorgchem.5c02399
SN - 0020-1669
VL - 46
IS - 36
SP - 18227
EP - 18236
PB - American Chemical Society (ACS)
AN - OPUS4-64078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Clauß, F.
A1 - Epple, Niklas
A1 - Ahrens, M. A.
A1 - Niederleithinger, Ernst
A1 - Mark, P.
T1 - Comparison of Experimentally Determined Two-Dimensional Strain Fields and Mapped Ultrasonic Data Processed by Coda Wave Interferometry
N2 - Due to the high sensitivity of coda waves to the smallest structural alterations such as strain, humidity or temperature changes, ultrasonic waves are a valid means to examine entire structures employing networks of ultrasonic transducers. In order to substantiate this ex ante assessment, the viability of measuring ultrasonic waves as a valid point of reference and inference for structural changes is to be further scrutinized in this work. In order to investigate the influence of mechanical strain on ultrasonic signals, a four-point bending test was carried out on a reinforced concrete beam at Ruhr University Bochum. Thus, measurements collected from a network of selected transducer pairings arranged across the central, shear-free segment of the test specimen, were correlated to their respective strain fields. Detected ultrasonic signals were evaluated employing Coda Wave Interferometry. Such analysis comprised the initial non-cracked state as well as later stages with incremental crack depth and quantity. It was to ascertain that the test specimen can in fact be qualitatively compartmentalized into areas of compression and tension identified via Relative Velocity Changes presented in Attribute Maps. However, since results did not entail a zero crossing, i.e., neither positive nor negative values were to be calculated, only relative changes in this work displayed staggered over the height of the object under test, are discussed. Under the given methodological premises, additional information is currently required to make quantitative assertions regarding this correlation of ultrasonic and strain results. This holds true for the comparability of the ultrasonic and strain results for both non-cracked and even the cracked state.
KW - Digital image correlation
KW - Fiber optic sensors
KW - Coda Wave Interferometry
KW - Ultrasound
KW - Concrete
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510501
DO - https://doi.org/10.3390/s20144023
SN - 1424-8220
VL - 20
IS - 14
SP - Paper 4023, 1
PB - MDPI
CY - Basel
AN - OPUS4-51050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hussein, S.
A1 - Kühl, A. A.
A1 - Golusda, L.
A1 - Plattner, C.
A1 - Heinze, N.
A1 - Sturm, G.
A1 - Freise, C.
A1 - Traub, Heike
A1 - Schannor, Mathias
A1 - Trajanoski, Z.
A1 - Taupitz, M.
A1 - Siegmund, B.
A1 - Paclik, D.
T1 - Phenotype and function of human monocytes remain mainly unaffected by very small superparamagnetic iron oxide particles
N2 - The field of medical application of organic or inorganic nanoparticles is extensive. Medical nanoparticles offer benefits but pose risks. For safe use in diagnostics and therapy, they should be inert, non-immunogenic, non-aggregating, and avoid long-term accumulation in sensitive tissues like bone marrow or the brain. We have developed in-house very small superparamagnetic iron oxide nanoparticles (VSOP), 7 nm in size, which have been successfully used in preclinical magnetic resonance imaging (MRI) to detect intestinal inflammation, neuroinflammation and atherosclerosis. This study examines nanoparticle effects on human blood cells focusing on monocytes in vitro as a first step toward clinical application. Whole blood and monocytes from healthy donors and patients with inflammatory bowel disease were treated with VSOP in vitro and analyzed for changes in their transcriptome, phenotype and function. RNA sequencing of monocytes identified the transferrin receptor as one of the most significantly downregulated genes after VSOP treatment, likely to limit iron uptake. Whereas whole blood RNA sequencing showed significant changes only in three non-coding genes. CyTOF analysis confirmed that VSOP-treated monocytes remain inactive, with no increased proliferation or altered migration. Metabolically, VSOP uptake enhanced the oxygen consumption rate. This effect was likely due to phagocytosis rather than effects mediated by the VSOP itself, as phagocytosis of latex beads showed comparable results. In summary, the analysis of peripheral blood mononuclear cells and monocytes suggests that VSOP treatment has no major impact on immune cell phenotype or function indicating VSOP as a promising diagnostic tool in MRI for inflammatory bowel disease.
KW - Imaging
KW - Nanoparticle
KW - Monocytes
KW - Contrast agent
KW - Diagnostics
KW - ICP-MS
KW - LA-ICP-MS
KW - VSOP
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632012
DO - https://doi.org/10.3389/fnano.2025.1584000
SN - 2673-3013
VL - 7
SP - 1
EP - 16
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-63201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Neubewertung von metallenen Dach- und Fassadenmaterialien unter Dauerhaftigkeits- und Umweltaspekten
N2 - Die Feldstudien haben gezeigt, dass die Dauer und Menge der Regenereignisse die Run-Off-Rate beeinflusst. Zwischen den Auslagerungsstandorten sind die Unterschiede gering. Bei Zink werden im ersten Jahr ca. 80 % der in Lösung gehenden Metallionen über den Run-OFF abgeschwemmt. Dagegen sind es bei Kupfer nur etwa 10 %. Grund ist die unterschiedliche Wasserlöslichkeit der gebildeten Korrosionsprodukte. Die Laborstudien haben gezeigt, dass der Einfluss von Regendauer und Regenmenge erwartungsgemäß hoch ist. Die Kombination aus geringer Dachneigung und einem pH-Wert von 4,5 führt zu den höchsten Run-Off-Raten für Zink und auch Kupfer. Zinkhydroxid-Korrosionsprodukte erhöhen die Run-Off-Rate, bis sich wasserunlösliche Zinkkarbonatschichten bilden.
T2 - Sitzung DIN NA 062-01-71 AA Korrosion und Korrosionsschutz
CY - Berlin, Germany
DA - 16.10.2024
KW - Korrosion
KW - Regensimulator
KW - Runoff
KW - Deckschichtbildung
KW - Metalleintrag in die Umwelt
PY - 2024
AN - OPUS4-61381
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Introduction to AGIL
N2 - An introduction to the Themenfeld Material project AGIL will be presented. The concept of the project, the work package structure and the material used within the project will be presented.
T2 - 2nd Workshop on In situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online meeting
DA - 19.04.2021
KW - AGIL
KW - Ageing
KW - Additive manufacturing
KW - Laser powder bed fusion
PY - 2021
AN - OPUS4-54107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Panzier, Nicole
A1 - Zocca, Andrea
T1 - Silikatkeramik und Hochleistungskeramik aus dem 3-D-Druck
N2 - In diesem Artikel werden die verschiedenen additiven Fertigungsverfahren und ihre Anwendungsmöglichkeiten vorgestellt. Der Fokus liegt hierbei auf Silikatkeramik. Für jedes 3D Druckverfahren werden die Möglichkeiten mit Silikatkeramik, Hochleistungskeramik und Dentalkeramik aufgezeigt. Auf den Nutzen der verschiedenen 3D Druckverfahren für industrielle Anwendungen, den privaten Bereich, sowie die Verwendung für Kunst und Design wird eingegangen. Das Potenzial der Additiven Fertigung wird auch für den Bereich der Keramik in der dentalen Anwendung bewertet.
KW - Additive Fertigung
KW - 3D Druck
KW - Silikatkeramik
KW - Hochleistungskeramik
PY - 2022
UR - https://www.quintessence-publishing.com/deu/de/article/3634513/quintessenz-zahntechnik/2022/12/silikatkeramik-und-hochleistungskeramik-aus-dem-3-d-druck
SN - 0340-4641
VL - 48
IS - 12
SP - 1260
EP - 1268
PB - Quintessence Publ.
CY - Berlin
AN - OPUS4-56792
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Design of finite temperature materials properties enabled by digital concepts
N2 - Since the function of materials is controlled by properties and processes on the atomic scale, ab initio based high-throughput methods are valuable strategies in materials design. For computational efficiency, they are however often restriction to T=0K calculations, while many technologically relevant materials properties and thermodynamic stabilities change when going from low to high temperatures. On the other hand, the constantly increasing performance of digital tools for simulation and data-driven science enables more targeted material development including these kinds of finite-temperature effects. A flexible infrastructure, including data management and workflow solutions is required to make this symbiosis user-friendly efficient. Within this presentation, examples from ab initio thermodynamics for the design of phase stabilities in hard-magnetic alloys and defect-phases in advanced high-strength steels will be demonstrated. We will discuss physical concepts with a focus at the impact of magnetic excitations. At the same time, the examples will be used to derive requirements and present solutions for a digital infrastructure. An outlook will be given to current strategies with the NDFI initiative NFDI-MatWerk.
T2 - HetSys Seminar Warwick University
CY - Warwick, UK
DA - 16.01.2023
KW - Digital Infrastructure
KW - Workflows
KW - Ab initio thermodynamics
KW - Compositionally complex alloys
KW - Hard magnets
PY - 2023
AN - OPUS4-58856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Castanon-Jano, Laura
A1 - Palomera-Obregon, Paula
A1 - Lázaro, Mariano
A1 - Blanco-Fernandez, Elena
A1 - Blasón Gonzalez, Sergio
T1 - Enhancing sustainability in polymer 3D printing via fusion filament fabrication through integration of by-products in powder form: Mechanical and thermal characterization
N2 - FFF (fused filament fabrication) is a type of 3D printing that utilizes filament for part creation. This study proposes using by-products or waste to replace part of the plastic in FFF filament, reducing environmental impact. The aim is to maintain a simple manufacturing process involving extrusion on a single-screw desktop machine followed by printing. The plastic matrix comprises polylactic acid (PLA) and polyethylene glycol (PETG), with added powdered by-products: seashells, car glass and mill scale (metal). Additives will be incorporated at 10% and 20% by weight, with two grain sizes: up to 0.09 mm and up to 0.018 mm. Mechanical tests (tensile, flexural and hardness) and thermal characterization tests will be conducted. Findings suggest adding 10%w powder of any variety to PETG increases tensile strength up to 48%, with metal powder (mill scale) showing the highest enhancement, even at 20%w, resulting in a 41% increase. Conversely, adding powder to PLA worsens mechanical properties without stiffening the material; instead, the elastic modulus decreases. Metal grain size has minimal impact, with grain sizes lower than 0.09 mm optimal for PLA. Thermal conductivity in polymers blended with powder additives is lower than in virgin polymers, likely due to air void formation, supported by density and microscopic evaluations. This research underscores the potential of utilizing waste materials with a simple FFF filament production to enhance sustainability in 3D printing practices.
KW - 3D printing
KW - FFF
KW - PLA
KW - PETg
KW - Metal powder
KW - Glass powder
KW - Seashells powder
KW - Tension
KW - Bending
KW - Thermal properties
KW - Sustainability
KW - Plastic consumption
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635027
DO - https://doi.org/10.1007/s00170-024-13635-3
SN - 0268-3768
VL - 133
IS - 3-4
SP - 1251
EP - 1269
PB - Springer
CY - London
AN - OPUS4-63502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - Ziele der Jungen GfKORR
N2 - Die Junge GfKORR soll ein attraktives Angebot für junge Leute sein, sich fachübergreifend zu vernetzen und einen Einstieg in Querschnittsthemen bieten. Sowohl der Korrosionsschutz zum Zwecke der Nachhaltigkeit und Sicherheit von Bauwerken als auch der Korrosionsschutz bei Energie- und Mobilitätssystemen soll in zukünftigen Veranstaltungen übergreifend betrachtet werden. Dabei wollen wir den fachlichen und informativen Input aus den Arbeitskreisen der GfKORR bei unseren Seminaren suchen. In diesem 1. Netzwerk- und Arbeitstreffen wurde die Fahrtrichtung der Jungen GfKORR genauer abgesteckt und es hat sich eine Leitungsebene gefunden. Weiter wollen wir ab 2024 interessante Präsenzveranstaltungen mit Exkursionen anbieten.
T2 - 1. Netzwerk- und Arbeitstreffen Junge GfKORR
CY - Berlin, Germany
DA - 12.03.2024
KW - Junge GfKORR
KW - Netzwerkbildung
KW - Corrosion
KW - Korrosion
PY - 2024
AN - OPUS4-60990
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Transforming Materials Science with Concepts for a Semantically Accessible Data Space
N2 - The digital transformation in materials science enables more efficient and sustainable processes. Through technological adaptations and a commitment to the FAIR principles, materials and processes are holistically addressed across entire value chains. The Platform MaterialDigital (PMD) and related initiatives are developing innovative solutions to the challenges of digitalization. The focus is on the interoperable integration of heterogeneous materials and processes data in semantically accessible data spaces. An ontological framework, based on the PMD Core Ontology and application-specific ontologies, promotes semantic interoperability of cross-domain and multi-scale (meta)data. This framework can be extended through natural language processing in a script-supported manner, as demonstrated with the Microscopy Ontology. The presentation further highlights how freely available mechanical and microstructural datasets of various aging stages of an aluminum alloy can be semantically integrated and flexibly searched. Graph-based operations enable links between processing and microstructural properties to be established, facilitating enhanced correlation analysis and pattern recognition.
T2 - TMS Specialty Congress 2025
CY - Anaheim, CA, USA
DA - 15.06.2025
KW - FAIR Data
KW - Semanitc Interoperability
KW - Community
KW - Reproducibility
PY - 2025
AN - OPUS4-63474
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Farhat, Abbas
A1 - Luu, Li-Hua
A1 - Doghmane, Alexis
A1 - Cuéllar, Pablo
A1 - Benahmed, Nadia
A1 - Wichtmann, Torsten
A1 - Philippe, Pierre
T1 - Micro and macro mechanical characterization of artificial cemented granular materials
N2 - The focus of this study is the experimental characterization of cemented granular materials, with the aim of identifying the microscopic properties of the solid bonds and describing the extension to macroscopic mechanical strength of cemented samples.We chose to use artificially bonded granular materials, made of glass beads connected by solid paraffin bridges. The results of several sets of laboratory tests at different scales are presented and discussed. Micromechanical tests investigate the yield strength of single solid bonds between particles under traction, shearing, bending and torsion loading, as a function of variations in particle size, surface texture and binder content. Macro-scale tensile tests on cemented samples explore then the scale transition, including influence of confining walls through homothetic variations of the sample size. Despite the large statistical dispersion of the results, it was possible to derive and validate experimentally an analytical expression for micro tensile yield force as a function of the binder content, coordination number and grain diameter. In view of the data, an adhesive bond strength at the contact between bead and solid bond is deduced with very good accuracy and it is even reasonable to assume that the other threshold values (shear force, bending and torsion moments) are simply proportional to the tensile yield, thus providing a comprehensive 3D model of cemented bond. However, the considerable dispersion of the data at the sample scale prevents validation of the extended model for macroscopic yield stress. A final discussion examines the various factors that may explain intrinsic variability. By comparison with other more realistic systems studied in the literature in the context of bio-cementation, our artificial material nevertheless appears suitable for representing a cemented granular material. Being easy to implement, it could thus enable the calibration of discrete cohesion models for simulation of practical applications.
KW - Cemented granular material
KW - Micro-mechanical characterisation
KW - Artificial soils
KW - Yield tensile stress
PY - 2024
DO - https://doi.org/10.1007/s10035-024-01426-2
SN - 1434-5021
VL - 26
IS - 3
SP - 1
EP - 20
PB - Springer
CY - Berlin
AN - OPUS4-63507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Data-Driven Materials Science Supported by Community, Reproducibility, and Standardization
N2 - Reproducible research in materials science demands a strong community and shared semantic standards. The interdisciplinary nature of the field has led to fragmented data practices, hampering collaboration and integration. Digitalisation initatives such as the German MaterialDigital Initiative addresses this by fostering a community-driven approach to FAIR data management, using ontologies to build consensus and semantic interoperability. Through interactive events like the Ontology Playground, a unified data culture that accelerates innovation and ensures reproducibility across materials research is supported.
T2 - Seminar of the Person Group
CY - Berkeley, CA, USA
DA - 23.06.2025
KW - FAIR Data
KW - Semantic Interoperability
KW - Community
KW - Reproducibility
PY - 2025
AN - OPUS4-63475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monavari, Mahshid
A1 - Sohrabi, Razieh
A1 - Motasadizadeh, Hamidreza
A1 - Monavari, Mehran
A1 - Fatahi, Yousef
A1 - Ejarestaghi, Negin Mousavi
A1 - Fuentes-Chandia, Miguel
A1 - Leal-Egaña, Aldo
A1 - Akrami, Mohammad
A1 - Homaeigohar, Shahin
T1 - Levofloxacin loaded poly (ethylene oxide)-chitosan/quercetin loaded poly (D,L-lactide-co-glycolide) core-shell electrospun nanofibers for burn wound healing
N2 - This study developed a new burn wound dressing based on core-shell nanofibers that co-deliver antibiotic and antioxidant drugs. For this purpose, poly(ethylene oxide) (PEO)-chitosan (CS)/poly(D,L-lactide-co-glycolide) (PLGA) core-shell nanofibers were fabricated through co-axial electrospinning technique. Antibiotic levofloxacin (LEV) and antioxidant quercetin (QS) were incorporated into the core and shell parts of PEO-CS/PLGA nanofibers, respectively. The drugs could bond to the polymer chains through hydrogen bonding, leading to their steady release for 168 h. An in vitro drug release study showed a burst effect followed by sustained release of LEV and QS from the nanofibers due to the Fickian diffusion. The NIH 3T3 fibroblast cell viability of the drug loaded core-shell nanofibers was comparable to that in the control (tissue culture polystyrene) implying biocompatibility of the nanofibers and their cell supportive role. However, there was no significant difference in cell viability between the drug loaded and drug free core-shell nanofibers. According to in vivo experiments, PEO-CS-LEV/PLGA-QS core-shell nanofibers could accelerate the healing process of a burn wound compared to a sterile gauze. Thanks to the synergistic therapeutic effect of LEV and QS, a significantly higher wound closure rate was recorded for the drug loaded core-shell nanofibrous dressing than the drug free nanofibers and control. Conclusively, PEO-CS-LEV/PLGA-QS core-shell nanofibers were shown to be a promising wound healing material that could drive the healing cascade through local co-delivery of LEV and QS to burn wounds.
KW - Core-shell nanofiber
KW - Co-axial electrospinning
KW - Drug delivery
KW - Burn wound
KW - Wound healing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635115
DO - https://doi.org/10.3389/fbioe.2024.1352717
SN - 2296-4185
VL - 12
SP - 1
EP - 14
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-63511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cortabitarte, G.
A1 - Llavori, I.
A1 - Esnaola, J.A.
A1 - Blasón Gonzalez, Sergio
A1 - Larrañaga, M.
A1 - Larrañaga, J.
A1 - Arana, A.
A1 - Ulacia, I.
T1 - Application of the theory of critical distances for fatigue life assessment of spur gears
N2 - This study evaluates the effectiveness of the theory of critical distances (TCD) method in determining the fatigue lifetime of a spur gear. A comprehensive characterization of the material parameters necessary for critical distance calculation was performed, including the fatigue limit and crack growth threshold, as well as σ-N and ε-N curves for 16MnCr5 steel. A variety of TCD methods were applied to analyse the component, including the point method, line method, volume method, and mesh control. The results indicate that overall, the TCD method is a reliable and accurate way to predict the fatigue lifetime of spur gears. The study reveals a strong correlation between predicted and experimental crack locations and fatigue lifetime, suggesting accurate prediction using TCD and the Smith-Watson-Topper parameter. Although all TCD methods, when applied correctly, yield similar results, mesh control is the faster method and is therefore more attractive from an industrial perspective. The results of this study provide valuable insight for engineers and researchers in the field of fatigue analysis of spur gears and similar mechanical components.
KW - Spur gear
KW - Theory of critical distances (TCD)
KW - Multiaxial fatigue
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624246
DO - https://doi.org/10.1016/j.tafmec.2023.104086
SN - 0167-8442
VL - 128
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Neubewertung von metallenen Dach- und Fassadenmaterialien unter Dauerhaftigkeits- und Umweltaspekten
N2 - Metallene Dach- und Fassadenmaterialien unterliegen nach ihrer Installation infolge von Korrosions- und Abschwemmprozessen einem Abtrag von Metallionen. Durch Regenereignisse gelangen diese in umliegende Gewässer und Böden. Die verwendeten metallenen Werkstoffe, wie z.B. Kupfer und Zink bilden zeitabhängig schützende Deckschichten aus, die die Dauerhaftigkeit der Werkstoffe gewährleisten und damit den Austrag von Metallionen signifikant begrenzen. Die Geschwindigkeit der Deckschichtbildung sowie die erreichte Schutzwirkung sind von verschiedenen Umwelteinflüssen und klimatischen Bedingungen abhängig. Diese haben sich in den letzten Jahrzehnten in Europa stark verändert, so dass es einer aktuellen Datenbasis für die Bewertung der Dauerhaftigkeit und der Umweltauswirkungen bedarf. Im Rahmen eines Forschungsvorhabens werden aktuell Feldstudien zur Ermittlung des Runoffs und der Schutzwirkung der gebildeten Deckschichten durchgeführt. Ergänzt werden diese durch Laborversuche mit künstlicher Beregnung.
T2 - 76. Sitzung DIN Arbeitsausschuss Korrosion und Korrosionsschutz
CY - Berlin, Germany
DA - 17.10.2023
KW - Atmosphärische Korrosion
KW - Runoff
KW - Deckschichtbildung
KW - Schutzwirkung
KW - Umgebungseinflüsse
PY - 2023
AN - OPUS4-58706
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Findeisen, Dietmar
A1 - Schröpfer, Dirk
T1 - Energy efficiency in materials testing by reactive power part 2: resonance method in fatigue testing
N2 - Reactive power is related to the type of power that does not consume energy but stores it. In the design of test machines, the utilization of this physical phenomenon would be very beneficial. Reactive power allows for the combination of power amplification with energy savings, making it an ideal principle for conducting long-term tests that involve high loads and prolonged energy consumption. This work focuses on testing machines operating in resonance, which allows for higher test frequencies and reduced test durations. Various types of fatigue testing machines, including those with rotating-unbalance actuators, servo-hydraulic actuators, and piezoelectric actuators, are examined through vibration analysis, methodical design, and mechatronics. Resonant testing machines provide significant advantages in energy efficiency and test accuracy for a wide range of applications in materials testing. These methods are crucial for future applications in industries where energy efficiency and precise fatigue testing are critical, such as aerospace, automotive, and civil engineering.
KW - Reactive power
KW - Amplitude magnification
KW - Power amplification
KW - Fatigue testing
KW - Resonant test machines
PY - 2024
DO - https://doi.org/10.1515/mt-2024-0350
SP - 1
EP - 11
PB - Walter de Gruyter GmbH
AN - OPUS4-62356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
A1 - Spaltmann, Dirk
A1 - Borras, Xavier
A1 - Llavori, Inigo
T1 - How shall we harmonize reciprocating friction tests?
N2 - Reciprocating friction tests are often used to investigate the tribological performance of systems. However, the evaluation of the coefficient of friction of these tests lacks harmonisation. This webinar hosted by TriboNet provides insights into this topic from different perspectives. At the same time, the community can engage with the creators of the “Tribology Challenge” hosted by i-TRIBOMAT.
T2 - TriboNet Webinar & Workshop „How Shall We Harmonize Reciprocating Friction Tests?”
CY - Online meeting
DA - 19.12.2024
KW - Standardisation
KW - Coefficient fo Friction
KW - Reciprocating
KW - Tribology Challenge
KW - Round Robin Tests
PY - 2024
AN - OPUS4-62479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Werder, Julia
T1 - Composite Facade Elements with Self-Cleaning Surface made of Ultra-High-Performance Concrete (UHPC)
N2 - In the framework of the European project H-House various concrete façade elements were developed with the aim to ensure a long service life by combining a very durable material with self-cleaning properties. The façade elements presented are made of a shell of UHPC filled with blocks of aerated autoclaved concrete as insulating material. Self-cleaning properties were realized amongst others by imprinting a microstructure into the surface during casting. The paper focuses on selected technological aspects of the manufacturing process of prototypes which had to be performed in two concreting sections. Furthermore the challenges faced when upscaling the self-cleaning properties are addressed and the strategy to assess the self-cleaning properties by measuring the contact and the roll-off angel is presented. The results show that a successfull upscalaing process requires detailed planning and that the best results can often be achieved with a moderate work effort or material use.
T2 - XV International Conference on Durability of Building Materials and Components (DBMC 2020)
CY - Online meeting
DA - 20.10.2020
KW - Ultra-High-Performance Concrete
KW - Facade Elements
KW - Self-Cleaning Properties
KW - Adhesive Pull-Strength
KW - Microstructure
KW - Architectural Concrete
PY - 2020
AN - OPUS4-51968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voigt, Marieke
T1 - Thermally treated UHPC: a durability study
N2 - Ultra high performance concrete (UHPC) is known for its high compressive strength of more than 150 MPa and its high durability. Thermal treatment at 90°C can accelerate the strength development so that the 28-days-strength can be achieved immediately after the treatment and an additional increase up to 30 % in some cases. The reason for the strength development is an accelerated hydration of the clinker minerals and an intensified pozzolanic reaction leading to a denser microstructure.
In previous research inhomogeneities in form of a zonation after unprotected thermal treatment were observed and analysed in respect to changes in the microstructure. This zonation is defined by a different microstructure in the core compared to the outer zone in the matter of porosity, mineral phase composition and a significant change in the potassium and sulphur concentration of the zones is measurable.
To isolate different transport mechanisms responsible for these element distributions UHPC samples were thermally treated at 90 °C and the microstructure was investigated under dry conditions and after immersion in water to investigate the influence of dehydration during and rehydration after the thermal treatment on the microstructure. Through durability testing via water absorption, water vapour diffusion, permeability testing and sulfuric acid resistance transport mechanisms like diffusion, migration, capillary suction are under investigation in correlation with the microstructure analysis. For the microstructure analysis measurements with µXRF, mercury intrusion porosity, XRD and SEM were conducted.
T2 - HiPerMat 2020
CY - Kassel, Germany
DA - 11.03.2020
KW - UHPC
KW - Thermal treatment
KW - Zonation
KW - Transport mechanism
KW - Durability
PY - 2020
AN - OPUS4-52372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kilinc, Sefine
T1 - Grinding method and oxidative aging of tire wear microplastics affect the fitness of the nematode C. elegans
N2 - This study gives a first insight in the toxicological relevance of tire wear MP on soil invertebrates. Both grinding technique and aging method had an effect on the results of the particle size distribution, particle properties and toxicity tests. This outcome highlights the importance of oxidative and mechanical aging of tire wear when investigating effects on soil biota. In particular the demonstrated differences due to grinding method of the pristine material questions scientific practice in common toxicity tests. It is essential to implement realistic refernce material as well as standardized aging and handling procedures.
T2 - Tire Emissions Research Conference 2024
CY - Munich, Germany
DA - 04.12.2024
KW - Nematode C. elegans
KW - Oxidative aging
KW - Tire wear
KW - Microplastics
PY - 2024
AN - OPUS4-62361
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Thermo mechanochemistry: merging heat and force for discovering new chemical transformations
N2 - Mechanochemistry is a hot topic in chemistry, and the number of researchers from academia and industry joining the field is growing. Mechanical action drives chemical reactions forward independently of the solubility of reactants and drastically minimises solvent usage and waste production. Mechanochemistry also provides other advantages, such as faster reaction times, higher yields, altered selectivity, and access to products not obtainable by other methods. Furthermore, recent innovations in mechanochemistry enable conducting chemical reactions by combining force and heat in approach called thermo-mechanochemistry [1]. These conditions typically overcome high activation energies and access products not obtainable by mechanochemistry at ambient temperature conditions. In this talk, I will give an overview to this emerging topic and to our discoveries by thermo-mechanochemistry that include prebiotic peptide bond formation [2], synthesis of amide-based active pharmaceutical ingredient [3], condensation of diamondoid derivatives [4], and manipulation of polymorphic transition temperatures in organic molecular crystals [5].
T2 - Department Seminar at Newcastle University
CY - Newcastle, UK
DA - 15.09.2023
KW - Mechanochemistry
PY - 2023
AN - OPUS4-62104
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Sustainable mechanochemical reaction engineering: from molecular mechanisms to scalable technology
N2 - In this talk, I will present about our quest to fundamentally understand mechanochemical reactions by in situ monitoring studies. Another of our interest is scaling up mechanochemistry. For example, we are now working on developing mechanochemical technology to enable a circular economy of plastics.
T2 - Hokkaido International Workshop on Mechanochemistry
CY - Hokkaido, Japan
DA - 29.09.2024
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2024
AN - OPUS4-62109
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Grinding away plastic waste: enabling the circular economy of plastics
N2 - Single-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or is being incinerated in a highly unsustainable manner. Plastic waste in the environment endangers ecosystems, and microplastics in babies raise alarming health concerns. Hence, one of the global priorities is circular economy for plastics which does not further exploit fossil fuel feedstocks. However, current technologies like mechanical recycling are inadequate, and innovative ones such as chemical recycling, i.e., converting plastics back to the starting monomers, are essential. For example, we can use the recycled monomers to make new plastics in a circular manner or upcycle them to other value-added functional materials. Here, I will present a sustainable technology we developed for the chemical recycling of polyethylene terephthalate (PET). PET represents 10% of global plastic production and dominates in plastic packaging. The technology relies on mechanochemistry (grinding) which uses mechanical action for the chemical breakdown of plastic polymers in an environmentally friendly way. The next step in our research is to use life cycle and techno-economic assessment to validate the sustainability and commercial viability of our technology with the goal of transferring it to real-world industrial application.
T2 - Berlin PostDoc Day 2023
CY - Berlin, Germany
DA - 02.11.2023
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2023
AN - OPUS4-62103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Bonse, Jörn
ED - Spaltmann, Dirk
T1 - Special issue: Laser-induced periodic surface nano- and microstructures for tribological applications
N2 - Laser material processing is an emerging technology that generates surface functionalities on the basis of optical, mechanical, or chemical properties. In the form of laser surface texturing (LST), it has attracted a remarkable amount of research to tailor surface properties towards various tribological applications. The main advantages of this single-step, laser-based technology are the contactless machining, featuring a high flexibility, efficiency, and speed, along with the excellent quality of the processed products. LST can be applied precisely localized to sub-micrometric areas, but, via laser beam scanning, it is also feasible for structuring large surface areas at the square meter size.
This Special Issue focuses on the latest developments concerning the tribological performance of laser-generated periodic surface nano- and microstructures and their applications. This includes the laser-based processing of different surface patterns, such as “self-organized” laser-induced periodic surface structures (LIPSS, ripples), grooves, micro-spikes, hierarchical hybrid nano-/micro-structures, microfeatures generated by direct laser interference patterning (DLIP), or even dimples or other topographic geometries shaped by direct laser modification or ablation. The applications of these periodically nano- and micro-patterned surfaces may improve the lubricated or non-lubricated tribological performance of surfaces in conformal and even non-conformal contact through a reduction of wear, a variation of the coefficient of friction, altered load carrying capacity, etc., resulting in energy saving, improved reliability, increased lifetimes as well as durability, leading in turn to extended maintenance intervals/reduced down-time. This can be beneficial in terms of bearings, gears, engines, seals, cutting tools, or other tribological components. Fundamental aspects addressed may involve the investigation of the relevant physical and chemical effects accompanying the laser-generated nano- and microscale topographies, such as alterations of the material structures, the hardness, superficial oxidation, the role of additives contained in lubricants, surface wettability, micro-hydrodynamic effects, etc.
For this Special Issue we aim to attract both academic and industrial researchers and would like to provide a bridge between research in the fields of tribology and laser material processing in order to foster the current knowledge and present new ideas for future applications and new technologies.
KW - Applications
KW - Friction
KW - Laser-induced periodic surface structures (LIPSS)
KW - Tribology
KW - Wear
PY - 2020
UR - https://www.mdpi.com/journal/lubricants/special_issues/laser_periodic
SN - 2075-4442
VL - 8
IS - 3
SP - Article 1
EP - Article 10
PB - MDPI
CY - Basel
AN - OPUS4-50914
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pelkner, Matthias
T1 - ZfP und Materialcharakterisierung mit GMR-Sensorarrays
N2 - Vorstellungen der Aktivitäten des Fachbereichs 8.4 im Bereich der elektromagnetischen Prüfmethoden. Hierbei werden insbesondere der Einsatz von magnetoresistiven Sensoren für die elektromagnetische ZfP thematisiert.
T2 - Gemeinsame Sitzung der DGZfP FA Wirbelstrom und Automotive
CY - Zwickau, Germany
DA - 06.03.2024
KW - Wirbelstromprüfung
KW - Magnetfeldsensoren
KW - GMR / TMR
KW - Magnetischer Streufluss
KW - Eigenspannungen
KW - plastische Verformung
PY - 2024
AN - OPUS4-61769
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Breaking the wall of circular plastics economy
N2 - Traditional mechanical recycling cannot process most plastic waste streams and most of the plastic waste currently goes to landfills or incineration. Chemical recycling is a promising technology to mitigate this but is hindered by high costs (due to high process temperatures and production of solvent waste). We developed a cost-efficient technology for chemical recycling of plastic waste that reduces greenhouse gas emissions and minimizes energy consumption. It is based on solvent-free mechanochemistry for depolymerization of plastic polymers at ambient conditions.
T2 - Falling Walls Lab Berlin-Adlershof
CY - Berlin, Germany
DA - 21.09.2023
KW - Mechanochemistry
KW - Recycling
KW - Circular economy
PY - 2023
AN - OPUS4-62101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Breaking the wall of circular plastics economy
N2 - Traditional mechanical recycling cannot process most plastic waste streams and most of the plastic waste currently goes to landfills or incineration. Chemical recycling is a promising technology to mitigate this but is hindered by high costs (due to high process temperatures and production of solvent waste). We developed a cost-efficient technology for chemical recycling of plastic waste that reduces greenhouse gas emissions and minimizes energy consumption. It is based on solvent-free mechanochemistry for depolymerization of plastic polymers at ambient conditions.
T2 - 2023 Falling Walls Science Summit
CY - Berlin, Germany
DA - 07.11.2023
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2023
AN - OPUS4-62102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
T1 - Modenabstoßung bei schwach und stark gekoppelten Lamb Wellen
N2 - Lamb-Wellen, die für ihre Bedeutung in der zerstörungsfreien Prüfung bekannt sind, zeigen komplexe Verhaltensweisen, die für industrielle Anwendungen von großer Relevanz sind. Diese Arbeit untersucht das Phänomen der Modenabstoßung, das in den Dispersionskurven von verklebten, dünnwandigen Platten beobachtet wird. Zudem wird dessen potenzielle industrielle Anwendung zur Quantifizierung der Haftfestigkeit zwischen diesen Platten erforscht. Das Phänomen resultiert aus der mechanischen Kopplung der Platten, die das Kreuzen der Dispersionskurven verhindert und zu einem interessanten dispersiven Verhalten führt. Um ein besseres physikalisches Verständnis zu erlangen, wird die Scaled-Boundary-Finite-Elemente-Methode eingesetzt, um die Lamb-Wellen-Moden gekoppelter Platten zu berechnen und ihr Verhalten unter schwacher und starker Kopplung zu simulieren. Mithilfe eines mathematischen Models und einer physikalischen Analogie zu einfachen harmonischen Oszillatoren werden die zugrundeliegenden Prinzipien dieses Phänomens erläutert. Darüber hinaus werden experimentelle Dispersionskurven für schwache und starke Kopplungen mithilfe von PZT-Wandlern für die breitbandige Anregung (100 kHz – 1 MHz) von Lamb-Wellen erfasst, wobei die Modendetektion durch Laser-Doppler-Vibrometrie erfolgt. Die numerischen Dispersionskurven werden mit den experimentellen verglichen, um die angeregten Moden zu identifizieren. Es zeigt sich, dass die Bereiche der Modenabstoßung durch die Kopplungsstärke der Platten beeinflusst werden. Zudem wurde ein numerisches Modell entwickelt, um die Kopplungsstärke anhand der Frequenzdifferenz, die in den Modenabstoßungsbereichen erhalten wurde, zu korrelieren und zu quantifizieren.
T2 - Doktorandenseminar in Joachimsthal
CY - Joachimsthal, Germany
DA - 28.10.2024
KW - Lamb waves
KW - Mode repulsion
KW - Mechanical coupling
KW - Dispersion curves
KW - Scaled Boundary Finite Element Method
PY - 2024
AN - OPUS4-62860
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
T1 - On the repulsion effect of coupled Lamb Wave modes
N2 - Lamb waves, recognized for their significance in material characterisation, structural health monitoring, and non-destructive testing, exhibit complex behaviours that are crucial for industrial applications. This paper delves into the mathematical and physical principals of the repulsion effect that can be observed in the dispersion curves of coupled Lamb wave modes. This effect is the result from the mechanical coupling of thin-walled solid plates and prevents the crossing of the dispersion curves. The study employs the Scaled Boundary Finite Element Method to calculate the dispersion curves of coupled plates and to simulate their interaction for a weak and ideal coupling. Through a mathematical framework and a physical analogy with simple harmonic oscillators, the paper elucidates the underlying principals of this effect. Furthermore, the paper highlights the practical significance of the repulsion effect in Lamb waves, suggesting its application for testing and monitoring the integrity of multi-layer structures like adhesive bonds, which are important for various industrial applications. A deepened understanding of this effect could contribute to the enhancement of non-destructive evaluation techniques.
T2 - ICSV 2024
CY - Amsterdam, Netherlands
DA - 08.07.2024
KW - Lamb waves
KW - Mode repulsion
KW - Scaled Boundary Finite Element Method (SBFEM)
KW - Mechanical coupling
KW - Dispersion curves
PY - 2024
AN - OPUS4-62857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
T1 - On the repulsion effect of coupled Lamb Wave modes
N2 - In dieser Arbeit wird der Modenabstoßungseffekt bei gekoppelten Lamb-Wellen untersucht. Wird eine mechanische Kopplung zwischen zwei Platten mit unterschiedlichen Materialeigenschaften eingeführt, so kreuzen sich deren Lamb-Wellen-Moden nicht mehr in den Dispersionsdiagrammen – stattdessen kommt es zur sogenannten Modenabstoßung. Dieser Effekt wird sowohl mathematisch als auch physikalisch erklärt, unter anderem durch eine Analogie zu gekoppelten harmonischen Oszillatoren. Numerische Simulationen mit der Scaled Boundary Finite Element Method (SBFEM) bestätigen die theoretischen Ergebnisse und zeigen eine klare Abhängigkeit der Frequenzaufspaltung vom Kopplungsgrad. Der Effekt ermöglicht Rückschlüsse auf Eigenschaften der Kopplungsschicht und bietet Potenzial für industrielle Anwendungen wie die Überwachung von Klebschichtzuständen in Mehrschichtstrukturen.
T2 - Doktorandenseminar
CY - Berlin, Germany
DA - 18.04.2024
KW - Lamb waves
KW - Mode repulsion
KW - Scaled Boundary Finite Element Method (SBFEM)
KW - Mechanical coupling
KW - Dispersion curves
PY - 2024
AN - OPUS4-62859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
T1 - On the repulsion effect of coupled Lamb Wave modes
N2 - This work investigates the phenomenon of mode repulsion in coupled Lamb wave systems. By mechanically coupling two dissimilar plates using spring elements, it is shown that previously intersecting Lamb wave modes are repelled, avoiding any crossing in the dispersion curves. The effect, rooted in eigenvalue theory and first observed in quantum systems, is explained through both mathematical models and classical analogies with coupled harmonic oscillators. Numerical simulations using the Scaled Boundary Finite Element Method validate the theoretical predictions, revealing a correlation between strain distribution and frequency splitting. The observed mode repulsion provides new insights into interface properties and offers potential for applications such as monitoring adhesive degradation in layered structures.
T2 - DAGA 2024
CY - Hannover, Germany
DA - 18.03.2024
KW - Lamb waves
KW - Mode repulsion
KW - Mechanical coupling
KW - Dispersion curves
KW - Scaled Boundary Finite Element Method (SBFEM)
PY - 2024
AN - OPUS4-62858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koch, Claudia
T1 - Digital Transformation in Conformity Assessment: International Study Insights & Current Initiatives in Germany
N2 - This presentation provides an overview on the key insights from our international study exploring the status and trends of digital transformation in conformity assessment bodies (e.g. testing and calibration laboratories, inspection and certification bodies) in 15 countries and regions worldwide. It covers comparative information from three main areas: their digital maturity, drivers & barriers, as well as the adoption of digital technologies. It further presents follow-up activities carried out at BAM, such as additional workshops with laboratories to deepen insights. Finally, it introduces the German QI-Digital initiative in which BAM together with key actors of the Quality Infarsrtucture develops solutions for a digital QI.
T2 - Empowering Quality Infrastructure through Digital Transformation
CY - Online meeting
DA - 11.12.2024
KW - Qualitätsinfrastruktur
KW - Quality Infrastructure
KW - Digitalisierung
KW - Digitale Transformation
KW - Laboratories
KW - Konformitätsbewertung
PY - 2024
AN - OPUS4-62177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schob, Daniela
T1 - Numerical and Experimental Investigation of Deformation Induced Martensitic Transformation in Fused Filament Fabricated Austenitic Stainless Steel for Cryogenic Applications
N2 - Cryogenic structural components, such as collars, bladders, keys for superconducting magnets, and elements of liquid hydrogen storage systems like hoses and valves, are frequently constructed from austenitic stainless steel due to its favorable properties. However, manufacturing these components using traditional methods is challenging due to their complex geometries. Additive manufacturing emerges as a promising solution, though a comprehensive understanding of the associated material behavior under extrem e conditions is still developing.
This study aims to explore the deformation induced martensitic transformation (DIMT) in fused
filament fabricated (FFF) 316L stainless steel through both experimental testing and numerical
simulation. The research focuses on predicting the material’s respo nse under tensile stress at ambient, 77K, and 4K temperatures.
Numerical simulations employ a finite element approach to incorporate the constitutive model and its temperature dependent phase transformation kinetics, enabling detailed investigation of stress and strain distributions at various cryogenic temperatures. These simulations are systematically calibrated and validated against corresponding experimental datasets, ensuring that the computational predictions mirror the observed microstructural evolution and macroscopic response under tensile loading. By comparin g simulation results to experimental findings obtained at temperatures from room temperature down to 4K, the reliability of the model can be assessed, and its predictive capabilities can be refined.
Ultimately, the research seeks to expand the understanding of DIMT in additively manufactured 316L components, supporting the development of advanced, simulation driven material models tailored for demanding cryogenic structural applications.
T2 - Cryogenic Engineering Conference (CEC) and International Cryogenic Materials Conference (ICMC)
CY - Reno, NV, USA
DA - 18.05.2025
KW - Phase transformation
KW - Deformation induced martensitic transformation
KW - 316L
KW - Fused Deposition Modelling
PY - 2025
AN - OPUS4-63238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Anja
A1 - Buchberger, G.
A1 - Stifter, D.
A1 - Duchoslav, J.
A1 - Hertwig, Andreas
A1 - Bonse, Jörn
A1 - Heitz, J.
A1 - Schwibbert, Karin
T1 - Spatial Period of Laser-Induced Surface Nanoripples on PET Determines Escherichia coli Repellence
N2 - Bacterial adhesion and biofilm formation on surfaces are associated with persistent microbial contamination, biofouling, and the emergence of resistance, thus, calling for new strategies to impede bacterial surface colonization. Using ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns), laser-induced periodic surface structures (LIPSS) featuring different submicrometric periods ranging from ~210 to ~610 nm were processed on commercial poly(ethylene terephthalate) (PET) foils. Bacterial adhesion tests revealed that these nanorippled surfaces exhibit a repellence for E. coli that decisively depends on the spatial periods of the LIPSS with the strongest reduction (~91%) in cell adhesion observed for LIPSS periods of 214 nm. Although chemical and structural analyses indicated a moderate laser-induced surface oxidation, a significant influence on the bacterial adhesion was ruled out. Scanning electron microscopy and additional biofilm studies
using a pili-deficient E. coli TG1 strain revealed the role of extracellular appendages in the bacterial repellence observed here.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser processing
KW - Polyethylene terephthalate
KW - Biofilm formation
KW - Cell appendages
KW - Biomimetic
KW - F pili
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537431
DO - https://doi.org/10.3390/nano11113000
VL - 11
IS - 11
SP - 3000
PB - MDPI
AN - OPUS4-53743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schiek, Manuela
A1 - Minenkov, Alexey
A1 - Hollweger, Sophia
A1 - Duchoslav, Jiri
A1 - Erdene-Ochir, Otgonbayar
A1 - Weise, Matthias
A1 - Ermilova, Elena
A1 - Hertwig, Andreas
T1 - Optical constants of In2O3-SnO2 (Indium tin oxide, ITO)
N2 - Optical constants of In2O3-SnO2 (Indium tin oxide, ITO)
Minenkov et al. 2024: on glass; n,k 0.191–1.69 µm
Optical constants of In2O3-SnO2 (Indium tin oxide, ITO)
Minenkov et al. 2024: on Si wafer, top; n,k 0.191–1.69 µm
Optical constants of In2O3-SnO2 (Indium tin oxide, ITO)
Minenkov et al. 2024: on Si wafer, bottom; n,k 0.191–1.69 µm
KW - Indium Tin Oxide
KW - Optical constants
KW - Magnetron Sputtering
KW - Electrochemical Degradation
KW - Spectroscopic Ellipsometry
PY - 2024
UR - https://refractiveindex.info/?shelf=other&book=In2O3-SnO2&page=Minenkov-glass
UR - https://refractiveindex.info/?shelf=other&book=In2O3-SnO2&page=Minenkov-wafer-top
UR - https://refractiveindex.info/?shelf=other&book=In2O3-SnO2&page=Minenkov-wafer-bottom
PB - Refractiveindex.info
AN - OPUS4-59766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Findeisen, Dietmar
A1 - Schröpfer, Dirk
T1 - Energy efficiency in materials testing by reactive power – part 1: power recirculating method in wear testing
N2 - Reactive power is related to the type of power that does not consume energy but stores it. In the design of test machines, the utilization of this physical phenomenon would be very beneficial. Reactive power allows for the combination of power amplification with energy savings, making it an ideal principle for conducting long-term tests that involve high loads and prolonged energy consumption. This concept is illustrated in this work focusing test machines used in rotary testing procedures. Drive element pairs, which serve as component test objects, are primarily exposed to wear stress. These stressed element pairs are consequently integral parts of a tribological system. The underlying principles of power amplification and power feedback are explained from the perspectives of drive technology, systematic design, methodical design, and mechatronics.
KW - Reactive power
KW - Power amplification
KW - Power feedback
KW - Wear testing
KW - Strained element pairs
PY - 2024
DO - https://doi.org/10.1515/mt-2023-0136
VL - 67
IS - 1
SP - 189
EP - 197
PB - Walter de Gruyter GmbH
AN - OPUS4-62355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rai, Alena
A1 - Stelzner, Ludwig
A1 - Weise, Frank
A1 - Wieland, M.
T1 - 3D-Analyse von Betonfahrbahnoberflächen mit Grinding- und Groovingtextur mittels Streifenlichtprojektion
N2 - Die Oberflächentexturierung der Betonfahrbahndecken mittels Grinding- und Grooving steht seit einigen Jahren im Mittelpunkt der Forschung und Entwicklung des Betonstraßenbaus in Deutschland. In den vergangenen Jahren wurden die vorteilhaften Oberflächenperformances derartiger Texturen wie z.B. Griffigkeit, Ebenheit, Lärmminderung in zahlreichen Forschungsprojekten umfassend untersucht und daraus die Technologie „Texturgrinding“ entwickelt.
Im Kontext des gegenwärtig verfolgten ganzheitlichen performanceorientierten Ansatzes liegt der Fokus nun verstärkt auf der Analyse und Charakterisierung der Oberflächentopografie von Grinding- bzw. Groovingtexturen. Insbesondere gilt ein Hauptaugenmerk hierbei der zeitlichen Entwicklung der Oberflächentexturen in Abhängigkeit von äußeren Einwirkungen durch Klima und Verkehr.
Dieser Beitrag zeigt, dass durch den Einsatz eines auf Streifenlichtprojektion basierenden Messsystems, eine hochaufgelöste dreidimensionale Erfassung der Oberflächentopografie verschiedenartiger Grinding- und Groovingtexturen möglich ist. Darauf aufbauend wurden messtechnische Voraussetzungen zur Gewährleistung reproduzierbarer Messungen geschaffen, die eine Dokumentation der zeitlichen Texturveränderungen infolge klimatischer Beanspruchung ermöglichen. Anschließend wurden Auswerteroutinen zur quantitativen und statistischen Charakterisierung der Oberflächentextur entwickelt und angewandt, um exemplarisch die Veränderungen der Oberflächentopografie infolge klimatischer Beanspruchung quantitativ abzubilden.
KW - Betonfahrbahndecken
KW - Grinding
KW - Grooving
KW - Oberflächentexturierung
KW - Streifenlichtprojektion
PY - 2020
DO - https://doi.org/10.1002/best.202000015
SP - 1
EP - 9
PB - Wilhelm Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG
CY - Berlin
AN - OPUS4-51012
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Delgado Arroyo, Diego
A1 - Börner, Andreas
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Lindner, T.
A1 - Löbel, M.
A1 - Preuß, B.
A1 - Lampke, T.
T1 - Ultrasonic assisted milling of a CoCrFeNi medium entropy alloy
N2 - Medium and High Entropy Alloys (MEA/HEA) are recently developed material classes, providing manifold applications, e.g., due to extraordinary structural properties. In that connection, the machinability as important issue for the processing of these materials was not in the scientific focus. This study focusses on experimental analysis of milling process conditions including ultrasonic assisted milling (USAM) and their effects on the resulting surface integrity of equiatomic CoCrFeNi-MEA specimens. For that reason, milling parameters (cutting speed, feed per cutting edge) were systematically varied for both conventional milling and USAM. The surface integrity was analyzed in terms of topography, defects, and residual stresses. Especially USAM leads to a decrease of occurring cutting forces and, hence, to an improvement of the surface integrity. Beneficial effects were observed in terms of lower tensile residual stresses at high cutting speed and feed per cutting edge.
KW - Medium entropy alloy
KW - Ultrasonic Assisted Machining
KW - Surface Integrity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554458
DO - https://doi.org/10.1016/j.procir.2022.05.203
VL - 108
SP - 879
EP - 884
PB - Elsevier B.V.
AN - OPUS4-55445
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Modification of Co Cr alloys to optimize of additively welded microstructures and subsequent surface finishing
N2 - Cobalt chromium alloys are often used in turbine and plant construction. This is based on their high thermal and mechanical stress resistance as well as their high wear resistance to corrosive and abrasive loads. However, cobalt is a cost-intensive material that is difficult to machine. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components in many sectors. Concerning inhomogeneity
and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. As a result of the high stresses on the components and requirements for a high surface quality, a complementary use of additive and machining manufacturing processes is necessary. Thereby, Co–Cr alloys are extremely challenging for machining with geometrically defined cutting edges because of their low thermal conductivity combined with high strength and toughness. An approach to solve this problem is to refine and homogenise the microstructure. This is achieved by modifying the alloy with elements zirconium and hafnium, which are added up to a maximum of 1 wt.-%. A reduction of the process forces and stresses on the tool and work piece surface is also achievable via hybrid milling processes. There are already studies on the combined use of additive and machining manufacturing processes based on laser technology. However, knowledge based on powder and wire-based arc processes is
important, as these processes are more widespread. Furthermore, the effects on the surface zone of additively manufactured components by hybrid finish milling have not yet been a subject of research. The results show that the structural morphology could be significantly influenced with the addition of zirconium and hafnium.
T2 - 74th IIW Annual Assembly
CY - Online meeting
DA - 12.07.2021
KW - Modification of structural morphology
KW - Co–Cr-alloy
KW - Plasma-transferred arc welding
KW - Ultrasonic-assisted milling
PY - 2021
AN - OPUS4-56670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Innovative Multielement-Legierungen: Ergebnisse zur Schweißbarkeit und Anwendungseigenschaften
N2 - Multielement-Legierungen (MPEA – multiple pricipal element alloys) stellen eine neue Klasse von Werkstoffen dar, die aus mindestens drei äquiatomaren Legierungselementen mit jeweils einem Gehalt von 5–35 Atom-% bestehen. Somit unterscheidet sich das Legierungskonzept fundamental von konventionellen bspw. Stahl- oder Al-basierten Legierungen. In jüngster Zeit lag der Schwerpunkt auf dem Legierungs-Design der MPEA und der Überprüfung bzw. Erreichung der gewünschten Eigenschaften bzw. -kombinationen. Hierzu werden die Legierungselemente gezielt ausgewählt und die Mikrostrukturen ein- und zum Teil auch mehrphasig eingestellt. Ziel sind hochinnovative MPEA mit angepassten Eigenschaften für die industrielle Anwendung. Dabei sollen insbesondere die bei konventionellen Legierungen wesentlichen Zielkonflikte, wie bspw. der Trade-off zwischen Festigkeit und Duktilität, überwunden werden. Darüber hinaus sind mechanische Eigenschaften bei sehr hohen sowie kryogenen Temperaturen bei gleichzeitig höchster Korrosionsbeständigkeit von hohem Interesse. Die Herstellung von Bauteilen erfordert dazu werkstoff- und beanspruchungsgerechte Füge- bzw. Schweißverfahren. Der Schweißeignung von MPEA wurde bis Ende 2021 nur äußert wenig Aufmerksamkeit zuteil. Die Auswirkungen durch Schweißprozesse auf die Metallurgie und die gewünschten Eigenschaften sind bisher kaum bekannt und limitieren die potenzielle Anwendbarkeit als Funktions- oder Konstruktionswerkstoffe.
In einem interdisziplinären BAM-Forschungsprojekt werden aktuell grundlegende Untersuchungen zur Schweißverarbeitung und resultierender Mikrostruktur-Anwendungseigenschafts-Beziehung verschiedener MPEA durchgeführt. Insbesondere Wärmeeinflusszone und Schweißgut sind geprägt durch eine Mikrostruktur, die aus Ungleichgewichtszuständen resultiert. Im Falle von MPEA wurde dies bisher nicht systematisch untersucht. Dazu erfolgte im Rahmen des Projektes eine umfassende Literaturauswertung zum Schweißen von MPEA und Zusammenfassung in einer umfassenden, systematischen Datenbasis. Aus diesem Grund sollen in der vorliegenden Studie die bisher bedeutsamsten Erkenntnisse zur Schweißbarkeit von MPEA systematisch nach MPEA-Typ und Schweißverfahren geordnet und mit eigenen aktuellen Forschungsergebnissen verglichen werden. Durch WIG- und Rührreibschweißversuche an den MPEA-Systemen CoCrNiFeMn bzw. CoCrNi konnten im Projektverlauf bereits wesentliche Fragestellungen beantwortet werden. Dazu zählen Auftreten bzw. Verhinderung intermetallischer Phasen/Seigerungen oder deren Auswirkung auf die Eigenschaften der Schweißverbindung (bspw. Festigkeit oder Korrosionsbeständigkeit).
T2 - DVS Congress
CY - Koblenz, Germany
DA - 19.09.2022
KW - High Entropy Alloy
KW - Schweißen
KW - Multielementlegierungen
PY - 2022
AN - OPUS4-56704
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Boschmann Käthler, C.
A1 - Ebell, Gino
A1 - Keßler, S.
A1 - Schiegg, Y.
A1 - Dauberschmidt, C.
A1 - Angst, U. M.
T1 - A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete: Particular consideration of 12% chromium steel
N2 - The critical chloride content C(crit) is an indicator for the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content C(crit) of mild and an alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests using more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, with the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing.
KW - Chloride‐induced corrosion
KW - Critical chloride content
KW - Reinforced concrete
KW - Testing methods
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529751
DO - https://doi.org/10.1002/maco.202112609
SN - 1521-4176
SP - 1
EP - 20
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-52975
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valet, Svenja
A1 - Burkert, Andreas
A1 - Ebell, Gino
A1 - Babutzka, Martin
T1 - Determination of the corrosion product layer resistance on zinc and electrolytically galvanized steel samples by using gel electrolytes
N2 - Although zinc and zinc coatings have been widely used for corrosion protection for decades new zinc coatings are constantly being developed. Characterizing the corrosion protectiveness of these new coatings, however, should not be underestimated. While exposure tests are time intensive, cyclic tests can only be used for a very limited field of application. Thus, electrochemical measurements provide both an efficient and an effective alternative. Conventional aqueous bulk electrolytes influence the surface layers of a tested zinc coating and are therefore not reliable. Gel electrolytes, however, have evolved over the last few years, are minimally invasive and provide reliable results.
This work describes experiments with gel electrolytes made of agar. Unlike previous work, it proposes a composition of gel electrolyte for minimally invasive description of the protective power of naturally formed oxide layers on zinc and zinc coatings. Therefore, as a first part, the gel electrolyte made of agar is verified as a method for zinc and zinc-coated samples. Afterwards, this paper introduces the corrosion product layer resistance RL as a promising parameter to evaluate the protective power of zinc coatings. Results are verified with EIS and FTIR measurements. An example on a representative zinc coating demonstrates the practical application.
KW - Gel electrolytes
KW - Agar
KW - Zinc coatings
KW - Atmospheric exposure
KW - Corrosion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526053
DO - https://doi.org/10.1016/j.electacta.2021.138191
SN - 0013-4686
VL - 385
SP - 138191
PB - Elsevier Ltd.
AN - OPUS4-52605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilhelm, Eugen
A1 - Mente, Tobias
A1 - Rhode, Michael
T1 - Waiting time before NDT of welded offshore steel grades under consideration of delayed hydrogen-assisted cracking
N2 - Offshore wind turbines (OWT) are a major goal of the energy strategy of Germany encompassing the increase of the installed wind power. OWT components are manufactured from welded steel plates with thicknesses up to 200 mm. The underlying standards and technical recommendations for construction of OWTs encompass specifications of so-called minimum waiting time (MWT) before non-destructive testing of the weld joints is allowed. Reason is the increased risk of time-delayed hydrogen assisted cold cracking as hydrogen diffusion is very slow due to the very thick plates. The strict consideration of those long MWT up to 48 h during the construction of OWTs leads to significant financial burden (like disproportionately high costs for installer ships as well as storage problems (onshore)). In this study, weld joints made of S355 ML were examined in comparison with the offshore steel grade S460 G2+M. The aim was to optimize, i.e., reduce, the MWT before NDT considering varied heat input, hydrogen concentration and using self-restraint weld tests. This would significantly reduce the manufacturing time and costs of OWT construction. To quantify the necessary delay time until hydrogen-assisted cold cracks appear, acoustic emission analysis was applied directly after welding for at least 48 h.
KW - Hydrogen
KW - Welding
KW - Cracking
KW - Offshore
KW - Steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524959
DO - https://doi.org/10.1007/s40194-020-01060-5
SN - 0043-2288
VL - 65
SP - 947
EP - 959
PB - Springer Nature
AN - OPUS4-52495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Erxleben, Kjell
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Mente, Tobias
A1 - Michael, Thomas
T1 - Local mechanical properties of dissimilar metal TIG welded joints of CoCrFeMnNi high entropy alloy and AISI 304 austenitic steel
N2 - Multiple principal element alloys encompass the well-known high entropy alloys (HEA). The alloy system represents a new class of materials consisting of at least three alloying elements, each containing 5 to 35 at.%. Thus, this alloying concept differs fundamentally from conventional materials such as steel or nickel alloys. For this purpose, the alloying elements are specifically selected, the microstructures are adjusted in a single-phase and, in some cases, multi-phase manner. In particular, conflicting goals, such as the trade-off between strength and ductility in conventional steels, are overcome. However, in the last 20 years, the focus has been on material synthesis. With the increase in available material quantities, the focus is now on processing issues such as joining and welding processes. The weldability of HEAs has received very little attention so far. The experience with dissimilar metal welds is completely lacking but is essential for the application of these materials in combination with conventional materials. The present study presents comprehensive experimental results on the weldability of an equimolar CoCrFeMnNi-HEA in cold-rolled and heat-treated condition, which was joined by tungsten inert gas welding to an austenitic steel AISI 304. The mechanical properties of the dissimilar metal welds were characterized by cross-weld tensile samples, whereas the local deformation in the weld of the different welding zones was measured by digital image correlation. In accordance with the respective initial HEA condition (cold-rolled vs. heat-treated), the local strain behavior was divergent and influenced the global mechanical properties of both DMW types. Nonetheless, the experiments provided proof in principle of the weldability for dissimilar joints of the CoCrFeMnNi-HEA welded to conventional materials like austenitic stainless steels ensuring a corresponding capability for mechanical loading. This allows further considerations on the application of these innovative materials.
KW - TIG welding
KW - High-entropy alloys
KW - Mechanical properties
KW - Dissimilar metal weld
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595775
DO - https://doi.org/10.1007/s40194-024-01718-4
SN - 0043-2288
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-59577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Giese, Marcel
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Michael, Thomas
A1 - Fritsch, Tobias
T1 - Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys
N2 - Multi-element systems with defined entropy (HEA—high entropy alloy or MEA—medium entropy alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcoming of the trade-off between high strength and ductility. Thus, the synthesis, the resulting microstructures, and properties of HEA have been primarily investigated so far. In addition, processing is crucial to achieve a transfer of potential HEA/MEA materials to real applications, e.g., highly stressed components. Since fusion welding is the most important joining process for metals, it is of vital importance to investigate the weldability of these materials. However, this has rarely been the subject of research to date. For that reason, in this work, the weldability depending on the surface preparation of a CoCrFeMnNi HEA and a CoCrNi MEA for TIG welding is investigated. The fusion welding of longer plates is described here for the first time for the CoCrNi alloy. The welds of both materials showed distinct formation of cracks in the heat affected Zone (HAZ). Optical and scanning electron microscopy analysis clearly confirmed an intergranular fracture topography. However, based on the results, the crack mechanism cannot be conclusively identified as either a liquid metal embrittlement (LME) or hot cracking-like liquid film separation.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - TIG welding
KW - Cracking
KW - High entropy alloy
KW - Medium entropy alloy
KW - Surface preparation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541697
DO - https://doi.org/10.3390/jmmp6010005
SN - 2504-4494
VL - 6
IS - 5
SP - 1
EP - 13
PB - MDPI
CY - Basel (CH)
AN - OPUS4-54169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - D'Accardi, E.
A1 - Krankenhagen, Rainer
A1 - Ulbricht, Alexander
A1 - Pelkner, Matthias
A1 - Pohl, Rainer
A1 - Palumbo, D.
A1 - Galietti, U.
T1 - Capability to detect and localize typical defects of laser powder bed fusion (L‑PBF) process: an experimental investigation with different non‑destructive techniques
N2 - Additive manufacturing (AM) technologies, generally called 3D printing, are widely used because their use provides a high added value in manufacturing complex-shaped components and objects. Defects may occur within the components at different time of manufacturing, and in this regard, non-destructive techniques (NDT) represent a key tool for the quality control of AM components in many industrial fields, such as aerospace, oil and gas, and power industries. In this work, the capability of active thermography and eddy current techniques to detect real imposed defects that are representative of the laser powder bed fusion process has been investigated. A 3D complex shape of defects was revealed by a μCT investigation used as reference results for the other NDT methods. The study was focused on two different types of defects: porosities generated in keyhole mode as well as in lack of fusion mode. Different thermographic and eddy current measurements were carried out on AM samples, providing the capability to detect volumetric irregularly shaped defects using non-destructive methods.
KW - Additive Manufacturing
KW - Defect detection
KW - Thermography
KW - Eddy-current testing
KW - Micro-computed tomography
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546680
DO - https://doi.org/10.1007/s40964-022-00297-4
SN - 2363-9512
VL - 7
IS - 6
SP - 1239
EP - 1256
PB - Springer
AN - OPUS4-54668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Franchin, G.
A1 - Zocca, Andrea
A1 - Karl, D.
A1 - Yun, H.
A1 - Tian, X.
T1 - Editorial: Advances in additive manufacturing of ceramics
N2 - Recently, additive manufacturing of ceramics has achieved the maturity to be transferred from scientific laboratories to industrial applications. At the same time, research is progressing to expand the boundaries of this field into the territory of novel materials and applications. This feature issue addresses current progress in all aspects of additive manufacturing of ceramics, from parts design to feedstock selection, from technological development to characterization of printed components.
KW - Additive manufacturing
KW - Ceramic
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549361
DO - https://doi.org/10.1016/j.oceram.2022.100277
SN - 2666-5395
VL - 10
SP - 1
EP - 2
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voigt, Marieke
T1 - Hydration and crystallization of Portland cement at 100 C
N2 - For the construction of hot water storage tanks, ultra high performance concrete proofed to be a suitable building material to ensure water tightness. Common storage tanks build with concrete are designed to endure temperatures up to 90 °C. To increase the energy efficiency however, modern tanks need to withstand temperatures above 100 °C. With increasing temperature and correlating water vapor pressures, the cement must meet new requirements. Thermodynamic modelling is a promising tool for predicting the phase stabilities of minerals in the cement within these temperature and pressure ranges (T/P). Thus, mixture designs can be investigated and optimized with regard to the expected mineral phases in selected T/P-ranges. Additionally, predictions of the long-term material behavior can be derived from thermodynamic data and subsequently the experimental effort can be reduced notably. On the other hand, validation of predictions is needed. The base for the thermodynamic model is a thermodynamic equilibrium and thus, the experimental data for validation should approach the presumed conditions of the equilibrium. This study investigates variable experimental conditions for the hydration of Portland cement at 100 °C to reach a sufficiently progressed development of the phase composition. In case of Portland cement, the highest degree of hydration achievable within a reasonable time span is the most significant parameter. Therefore, Portland cement pastes with w/c ratios from 0.4 to 0.6 and dwell times up to three weeks were examined with powder X-ray diffraction to identify mineral phase changes. At 100 °C and high humidity, Portland cement paste shows the expected mineral phases like portlandite, katoite, and remaining clinker phases. The cement pastes with high water content and long dwell time seem to have the highest degree of hydration, even though the AFm phases stabilize with increasing w/c ratio. A dwell time of two weeks and a w/c ratio of 0.5 was found to provide the mineral composition with the highest degree of hydration including the major phase transitions.
T2 - 4th International Conference on the Chemistry of Construction Materials (ICCCM)
CY - Karlsruhe, Germany
DA - 26.09.2022
KW - Hydration
KW - High temperature
KW - Portland cement
PY - 2022
AN - OPUS4-56866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voigt, Marieke
T1 - The adaption of the set-up for gas permeability measurements for ultra-high performance concrete
N2 - In the framework of this project, a steam pressure vessel was to be developed from ultra-high perfor-mance concrete (UHPC) to withstand process temperatures of 200 °C and the respective steam pressure of 15,5 bar. To guarantee the long-term water vapour tightness of the system, the permeability of two UHPC mixtures were tested after long-term cyclic autoclaving. As UPHC shows a high density and therefore low permeability, measurements after the RILEM-Recommendation (TC 116-PCD) reached their detection limit. Therefore, the measurement set-up was adapted to measure the permeability of highly dense UHPC more reliably and quickly. This adaption includes measurements in a higher pres-sure range, the change of sample size thickness and the usage of Ar as a medium compared with the RILEM Recommendation. Additionally, the system was equipped with two pressure sensors and Ar-flowmeters to guarantee a continuous record of the experimental parameters. The new system was tested and evaluated by comparing measurements with the RILEM recommended system. Preliminary results show that the adapted system is capable to provide efficient and reliable results of concrete with low permeability.
T2 - 14th fib PhD Symposium in Civil Engineering
CY - Rome, Italy
DA - 05.09.2022
KW - Hydration
KW - High temperature
KW - Portland cement
PY - 2022
AN - OPUS4-56859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
T1 - Junior Research Group Materials Characterization and Informatics for Sustainability in Civil Engeneering (CE)
N2 - Vorstellung der Themen der Nachwuchsgruppe "Materialcharakterisierung und -informatik für die Nachhaltigkeit im Bauwesen" von Prof. Sabine Kruschwitz (TU Berlin und BAM)
T2 - Themenkonferenz Nachhaltiges Bauen
CY - Berlin, Germany
DA - 08.12.2022
KW - Recycling
KW - NMR
KW - Materialcharakterisierung
KW - Data Science
PY - 2022
AN - OPUS4-56648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koch, Claudia
A1 - Hilgenberg, Kai
T1 - Eine moderne Qualitätsinfrastruktur: digital und vernetzt
N2 - Der Vortrag stellt die Arbeiten der BAM in der Initiative QI-Digital vor, in deren Rahmen Lösungen für eine moderne und digitale Qualitätsinfrastruktur entwickelt werden. Schwerpunkt liegt auf dem zentralen Werkzeug Quality-X sowie dem Pilotprojekt "Moderne Qualitätssicherung in der Additiven Fertigung".
T2 - BAM Kuratoriumssitzung
CY - Berlin, Germany
DA - 22.06.2023
KW - Qualitätsinfrastruktur
KW - Digitalisierung
KW - Quality-X
KW - Additive Fertigung
PY - 2023
AN - OPUS4-58121
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adwani, D.
A1 - Pipintakos, G.
A1 - Mirwald, J.
A1 - Wang, Y.
A1 - Hajj, R.
A1 - Guo, M.
A1 - Liang, M.
A1 - Jing, R.
A1 - Varveri, A.
A1 - Zhang, Y.
A1 - Pei, K.
A1 - Xu, X.
A1 - Leng, Z.
A1 - Li, D.
A1 - Villamil, W.
A1 - Caro, S.
A1 - Chailleux, E.
A1 - Cantot, J.
A1 - Weigel, Sandra
A1 - Škulteckė, J.
A1 - Tarsi, G.
A1 - Margaritis, A.
A1 - Wang, H.
A1 - Hu, Y.
A1 - Airey, G.
A1 - Sreeram, A.
A1 - Bhasin, A.
T1 - Examining the efficacy of promising antioxidants to mitigate asphalt binder oxidation: Insights from a worldwide interlaboratory investigation
N2 - Oxidative aging induces significant stiffening of asphalt binders that leads to a pronounced reduction in the overall durability of asphalt pavements. The strategic implementation of antioxidant additives provides a potential solution to alleviate this issue. This work presents results from the second phase of the global consortium for antioxidants research aimed at investigating the effectiveness of potential antioxidants in increasing the durability of asphalt binders. Sixteen laboratories around the world participated in this effort and a total of 28 binders from diverse geographical regions were tested. Two promising antioxidants, namely zinc diethyldithiocarbamate (ZDC) and kraft lignin were evaluated in this phase and blended with the binders at specific proportions. Subsequently, a comprehensive investigation was conducted to assess rheological characteristics and chemical properties of the various blends, utilising Dynamic Shear Rheometer (DSR) measurements and Fourier Transform Infrared (FTIR) Spectroscopy. The findings indicate that additives such as ZDC hold considerable promise as an effective antioxidant, particularly when considering a wide diversity of binders. In general, its incorporation does not compromise the rutting performance of the binders and significantly improves fatigue performance. Therefore, research efforts should be focused on exploring additional facets to assess its practical applicability in field.
KW - Asphalt oxidation
KW - Binder aging
KW - Antioxidant additives
KW - Binder rheology
KW - Binder chemistry
KW - Bitumen und bitumenhaltige Bindemittel
KW - FTIR-Spektroskopie
KW - Anwendungsmöglichkeiten
KW - Vergleichsuntersuchung
KW - Arbeitsanleitung
KW - Präzision
PY - 2024
DO - https://doi.org/10.1080/10298436.2024.2332363
SN - 1477-268X
VL - 25
IS - 1
SP - 1
EP - 15
PB - Taylor & Francis
CY - London
AN - OPUS4-59957
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Diercks, Philipp
A1 - Gläser, D.
A1 - Lünsdorf, O.
A1 - Selzer, M.
A1 - Flemisch, B.
A1 - Unger, Jörg F.
T1 - Evaluation of tools for describing, reproducing and reusing scientific workflows
N2 - In the field of computational science and engineering, workflows often entail the application of various software, for instance, for simulation or pre- and postprocessing. Typically, these components have to be combined in arbitrarily complex workflows to address a specific research question. In order for peer researchers to understand, reproduce and (re)use the findings of a scientific publication, several challenges have to be addressed. For instance, the employed workflow has to be automated and information on all used software must be available for a reproduction of the results. Moreover, the results must be traceable and the workflow documented and readable to allow for external verification and greater trust. In this paper, existing workflow management systems (WfMSs) are discussed regarding their suitability for describing, reproducing and reusing scientific workflows. To this end, a set of general requirements for WfMSswere deduced from user stories that we deem relevant in the domain of computational science and engineering. On the basis of an exemplary workflow implementation, publicly hosted at GitHub (https:// this http URL), a selection of different WfMSs is compared with respect to these requirements, to support fellow scientists in identifying the WfMSs that best suit their requirements.
KW - FAIR
KW - Reproducibility, scientific workflow
KW - Tool comparison
KW - Workflow management
PY - 2024
UR - https://arxiv.org/abs/2211.06429
DO - https://doi.org/10.48550/arXiv.2211.06429
PB - Arxiv; Cornell Tech
CY - New York, NY
AN - OPUS4-59804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigel, Sandra
T1 - Estimating aging sensitivity of bitumen using FTIR spectroscopy and multivariate evaluation
N2 - In this work, a methodology based on Fourier transform infrared (FTIR)spectroscopy and multivariate evaluation is presented to estimate the aging sensitivity of bitumen based on the unaged samples and thus without the need for time- and material-consuming aging simulations. For this purpose, factor analysis and linear discriminant analysis are used to develop a statistical model based on the FTIR spectra of unaged bitumen samples, which can be used fast and simple in everyday laboratory work and allows to assign the bitumen to a low, moderate, or strong aging sensitivity. The evaluation of the aging sensitivity is based on the complex shear modulus|G* | and the phase angle δ from the measurement with a dynamic shear rheometer(DSR), whose aging-related changes were captured as the slope in the Black diagram. A relevant influence on the classification concerning the aging sensitivity has the oxygen-containing compounds(sulfoxide, hydroxyl and partly carbonyl compounds), whereby lower contents and thus less preaged bitumen tend to have a stronger aging sensitivity. However, in addition to the oxygen-containing compounds, the structure of the aliphatic and aromatic compounds and, in particular, the interaction of the different structures are decisive for the aging sensitivity
KW - Bitumen
KW - Ageing behaviour
KW - Characterisation
KW - FTIR
KW - Multivariate analysis methods
PY - 2023
DO - https://doi.org/10.1088/2631-8695/acdce0
SN - 2631-8695
VL - 5
IS - 2
SP - 1
EP - 14
PB - IOP Publishing
AN - OPUS4-58020
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bintz, Thilo
T1 - Detailed investigation of capillary active insulation materials by 1H nuclear magnetic resonance (NMR) and thermogravimetric drying
N2 - Capillary active interior insulation materials are an important approach to minimize energy losses of historical buildings. A key factor for their performance is a high liquid conductivity, which enables redistribution of liquid moisture within the material. We set up an experiment to investigate the development of moisture profiles within two different interior insulation materials, calcium-silicate (CaSi) and expanded perlite (EP), under constant boundary conditions. The moisture profiles were determined by two different methods: simple destructive sample slicing with subsequent thermogravimetric drying as well as non-destructive NMR measurements with high spatial resolution. The moisture profiles obtained from both methods show good agreement, when compared at the low spatial resolution of sample slicing, which demonstrates the reliability of this method. Moreover, the measured T2- relaxation-time distributions across the sample depth were measured, which may give further insight into the saturation degree of the different pore sizes. In order to explain differences in the moisture profiles between CaSi and EP, we determined their pore-size distribution with different methods: conversion of the NMR T2 relaxationtime distribution at full saturation, mercury intrusion porosimetry and indirect determination from pressure plate measurements. CaSi shows a unimodal distribution at small pore diameters, while in EP, a bi-modal or wider distribution was found. We assume that the smaller pore diameters of CaSi lead to a higher capillary conductivity, which causes a more distributed moisture profile in comparison with that of EP.
T2 - NDT-CE
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Insulation material
KW - Nuclear magnetic resonance
KW - Capillary conductivity
KW - Pore-size distribution
PY - 2022
AN - OPUS4-57918
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigel, Sandra
A1 - Wetekam, J.
A1 - Mollenhauer, K.
T1 - Identification and classification of PAH in asphalt binders with FTIR spectroscopy and multivariate analysis methods
N2 - Reclaimed asphalt pavements (RAP) with increased contents of polycyclic aromatic hydrocarbons (PAH) are restricted for reuse due to their harmful effects on humans and the environment. This work investigated whether Fourier transform infrared (FTIR) spectroscopy is suitable for a fast and simple identification and quantification of PAH in binders recovered from reclaimed asphalts. For this, the binders from 34 RAP samples were recovered using a rapid procedure developed at the Universität Kassel and were examined with infrared spectroscopy. The obtained spectra were pre-processed (Standard Normal Variate transformation, 1st derivative) and evaluated using a combination of factor analysis and linear discriminant analysis. The results showed that various PAH groups with differently pronounced aromatic structures are present in the binders.
However, with FTIR spectroscopy combined with the multivariate methods, a statistical model was developed allowing for the differentiation between the PAH groups and also for the distinction between PAH contents below or above the threshold of 25 mg/kg valid in Germany.
KW - Polycyclic aromatic hydrocarbons PAH
KW - Reclaimed asphalt
KW - Rapid procedure for binder extraction
KW - FTIR spectroscopy
KW - Multivariate analysis methods
PY - 2023
DO - https://doi.org/10.1016/j.fuel.2022.126845
SN - 0016-2361
VL - 337
SP - 1
EP - 7
PB - Elsevier Ltd.
AN - OPUS4-56961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hirsch, T.
T1 - Impact of autoclaving on the phase assemblage of Portland cement: Experiment and thermodynamic modelling
N2 - Even after autoclaving for 2 weeks in the temperature range of 120 to 200 °C, CEM I paste with a water-to-cement ratio of 0.5 still contains some low-crystalline C-S-H. The conversion of low-crystalline C-S-H to crystalline is faster with increasing temperature. The observed low-crystalline and crystalline C-S-H phases (reinhardbraunsite, jaffeite) indicate that the samples have not reached equilibrium yet under these experimental conditions. However, there is a good agreement between experiment and thermodynamic modelling for the other solids indicating that the used datasets are suitable for this application.
T2 - 16th International Congress on the Chemistry of cement 2023 - ICCC2023
CY - Bangkok, Thailand
DA - 18.09.2023
KW - Zement
KW - Thermodynamik
KW - Phasenzusammensetzung
KW - Mineralogie
KW - Modellierung
PY - 2023
UR - https://iccc2023.org
AN - OPUS4-58967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Birgit
A1 - Dehn, F.
A1 - Unger, Jörg F.
A1 - Shepherd, D. A.
A1 - Tamsen, Erik
A1 - Pirskawetz, Stephan
T1 - Wissensbasierte Digitalisierung von betontechnologischen Materialdaten
N2 - Die sprunghaft zunehmende Wichtigkeit von FAIR- und Open-Data für die Qualitätssicherung, aber auch für die Nachnutzbarkeit von Daten und den Erkenntnisfortschritt führt zu enormem Flandlungsbedarf in Forschung und Entwicklung. Damit verbunden laufen derzeit vielfältige, ambitionierte Aktionen, z. B. bezüglich der Erstellung von Ontologien und Wissensgraphen. Das Knowhow entwickelt sich rasant, die Ansätze zur Implementation entstehen in verschiedenen Fachwelten bzw. mit
unterschiedlichen Zielsetzungen parallel, so dass recht heterogene Herangehensweisen resultieren.
Diese Veröffentlichung fokussiert auf Arbeiten, die derzeit als möglichst ganzheitlicher Ansatz für Materialdaten im Rahmen der Digitalisierungsinitiative „Plattform MaterialDigital" vorangetrieben werden. Die Autoren bearbeiten baustoffbezogene Aspekte im Verbundprojekt „LeBeDigital - Lebenszyklus von Beton". Zielsetzung ist die digitale Beschreibung des Materialverhaltens von Beton über den kompletten Herstellungsprozess eines Fertigteils mit einer Integration von Daten und Modellen innerhalb eines Workflows zur probabilistischen Material- und Prozessoptimierung.
Es wird über die Vorgehensweise und die dabei gewonnenen Erfahrungen berichtet, nicht ohne den Blick auf die oft unterschätzte Komplexität der Thematik zu lenken.
T2 - Internationale Baustofftagung (ibausil)
CY - Weimar, Germany
DA - 13.09.2023
KW - Beton
KW - Digitalisierung
KW - Materialdaten
KW - Datenmanagement
KW - FAIR-Prinzip
KW - Metadaten
KW - Ontologie
KW - Wissengraph
PY - 2023
UR - https://www.uni-weimar.de/de/bauingenieurwesen/institute/fib/ibausil/
VL - 2023
SP - 1
EP - 11
PB - Sonderausgabe des Online-Journals ce/papers von Wiley
AN - OPUS4-58315
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stohl, Leonie
A1 - Manninger, T.
A1 - von Werder, Julia
T1 - Biofilmfassaden; Begrünung von Beton auf der Mikroskala
N2 - Die Klimakrise führt zu einer steigenden Nachfrage nach ökologisch orientierten Konzepten. Dazu gehören im Baubereich nicht nur umweltfreundliche Materialien, sondern auch die Begrünung städtischer Gebiete.
Vor diesem Hintergrund wird ein Projekt vorgestellt, dass eine Fassadenbegrünung mithilfe von mikrobiellen Organismen wie Algen statt höheren Pflanzen realisieren will. Die Entwicklung von sogenannten biorezeptiven Materialien ist eine Herausforderung, weil es aktuell noch keine standardisierten Methoden zur Bestimmung der Biorezeptivität gibt. Um ein grundlegendes Verständnis für die Prozesse und Interaktionen zwischen Organismen und Substrat zu gewinnen, werden Betonplatten unterschiedlich strukturiert und ihre Oberflächencharakteristiken dokumentiert. Anschließend werden die Platten unter verschiedensten Bedingungen bewittert und auf ihre Biorezeptivität untersucht.
Von besonderem Interesse sind hierbei Einfluss der materialintrinsischen Oberflächenparameter sowie der Umwelt. Langfristig wird geplant ein geeignetes Messkonzept vorzuschlagen, das Materialwissenschaft und Biologie verbindet und verlässliche Vorhersagen zur Biorezeptivität eines Materials treffen kann.
In der vorliegenden Arbeit liegt der Schwerpunkt auf dem theoretischen Ansatz und der Versuchsplanung.
T2 - Internationale Baustofftagung (ibausil)
CY - Weimar, Germany
DA - 13.09.2023
KW - Biorezeptivität
KW - Beton
KW - Fassadenbegrünung
KW - pH-Messungen
KW - Rauheit
KW - Benetzungsverhalten
KW - Materialdesign
PY - 2023
UR - https://www.uni-weimar.de/de/bauingenieurwesen/institute/fib/ibausil/
SP - 1
EP - 8
PB - Sonderausgabe des Online-Journals ce/papers von Wiley
AN - OPUS4-58303
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fladt, Matthias
A1 - Weise, Frank
T1 - Bewertung der Innenhydrophobierung als neuartige AKR-Vermeidungsstrategie bei Betonfahrbahndecken
N2 - Zur Vermeidung von AKR-Schäden an Betonfahrbahndecken im deutschen Autobahnnetz wurden mit dem ARS 04/2013 verbindliche Eignungsprüfungen zum Ausschluss alkaliempfindlicher Gesteinskörnungen bei Neubau- und Erhaltungsmaßnahmen eingeführt. Das hatte eine signifikante Reduzierung geeigneter Gesteinskörnungen zur Folge. Deshalb wird geprüft, ob durch die Zugabe eines Hydrophobierungsmittels während der Betonherstellung grenzwertig alkaliempfindliche Gesteinskörnungen nutzbar gemacht werden können. In diesem Beitrag wird der Einfluss der Dosierung eines Compounds mit Hydrophobierungsmittel (HM) auf die Frisch- und Festbetoneigenschaften eines Waschbetons mit einer reaktiven Grauwacke dargestellt. Es zeigt sich, dass aufgrund des Antagonismus die zunehmende Dosierung des HM-Compounds eine signifikante Erhöhung der Zugabe des Luftporenbildners auf Wurzelharzbasis erfordert. Der AKR-Schädigungsprozess wird ab einer Dosierung des HM-Compounds von 0,75 M.-%, bezogen auf den Zementgehalt, hinreichend vermindert. Die mechanischen Eigenschaften des hydrophobierten Waschbetons verschlechtern sich im betrachteten Dosierungsbereich des HMCompounds nur geringfügig. Auch der Frost-Tausalz-Widerstand vermindert sich, ohne den normativen Grenzwert für die Abwitterung zu überschreiten.
T2 - Internationale Baustofftagung (ibausil)
CY - Weimar, Germany
DA - 13.09.2023
KW - Betonfahrbahndecke
KW - Alkali-Kieselsäure-Reaktion
KW - Massenhydrophobierung
KW - AKRVermeidungsstrategie
PY - 2023
UR - https://www.uni-weimar.de/de/bauingenieurwesen/institute/fib/ibausil/
VL - 2023
SP - 1
EP - 10
PB - Sonderausgabe des Online-Journals ce/papers von Wiley
AN - OPUS4-58317
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stohl, Leonie
A1 - von Werder, Julia
A1 - Manninger, T.
T1 - Bioreceptive concrete: Greening facades on the microscale
N2 - The accelerating climate crisis results in a rising demand for ecologically driven concepts. Regarding construction, this does not only include environmentally friendly materials but also the establishment of greenery in urban regions.
This contribution presents the progress of two projects in which textured concrete slabs were designed to grow a stable biofilm of photosynthetic eukaryotic organisms. The greened panels represent an alternative to classic fa9ade greening with plants. Current literature suggests that the development of bioreceptive surface materials in the construction sector is difficult because there are no standardized methodological approaches for measuring said bioreceptivity. Therefore, the long-term. ahn is proposing a suitable measurement concept combining material Science and biology. Among other things, the intrinsic Substrate property pH value is expected to have a significant influence on biological colonization. In the current contribution the focus lies on the theoretical approach and design of experiment regarding this parameter.
Available experimental data will be presented.
T2 - 77th RILEM Annual Week and the 1st Interdisciplinary Symposium on Smart & Sustainable Infrastructures (ISSSI 2023)
CY - Vancouver, Canada
DA - 04.09.2023
KW - Bioreceptivity
KW - Concrete
KW - Surface pH measurement
KW - Material characterization
KW - Green Facade
PY - 2023
UR - https://www.rilemweek2023.com/submissions/
SP - 1
EP - 6
AN - OPUS4-58304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
T1 - AI-Driven Material Design: Accelerating Innovation with SLAMD
N2 - In the Horizon Europe-funded project REINCARNATE, a user-friendly web application, the "Sequential Learning App for Materials Discovery" (SLAMD), was developed to revolutionize the materials design process [1]. By integrating a digital lab twin with AI-driven approaches, SLAMD supports and significantly accelerates the discovery of optimal material compositions within complex parameter spaces, while considering eco-efficiency and cost-effectiveness. Its versatility and practical relevance are demonstrated through diverse applications:
SLAMD is being used to develop two classes of concrete incorporating recycled materials, each with unique requirements and constraints imposed by regulations and industry standards. The first application focuses on optimizing compressive strength with at least 30 % substitution of the CEM II binder using a mix of recycled glass powder and concrete fines. The second targets the formulation of concrete for five exposure classes, exceeding the regulatory limit of 50 % recycled aggregates while meeting all performance criteria. Besides finding new concrete mixes with a higher percentage of recycling materials in their composition, these demonstration cases aim also to spread the use of SLAMD as a tool for industry stakeholders.
In collaboration with the industrial partner Holcim (Germany) GmbH, SLAMD accelerated the development process of concrete with high carbonation resistance by a factor of 80 %. This success was further enhanced by incorporating NMR features from non-carbonated sister samples at only 28 days of age, revealing additional acceleration potential [2]. Currently, the integration of non-destructive testing methods, such as Laser-Induced Breakdown Spectroscopy, is being explored to further shorten development cycles.
Another example is the use of SLAMD within the Volkswagen Foundation-funded project "Circular B-IO," where it is adapted and applied to optimize the heterogeneous material flow of recycled substances. By creating homogenized supply streams, SLAMD contributes to the reliable production of low-carbon concrete in Kenya, enabling more sustainable construction practices.
Looking ahead, SLAMD may be used to address a wide range of material-related challenges. Through its ability to navigate complex datasets and identify promising solutions efficiently, it opens new opportunities for advancing material design, accelerating innovation, and promoting sustainability.
T2 - MaterialsWeek 2025
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - SLAMD
KW - Carbonation resistance
KW - REINCARNATE
KW - Nuclear magentic resonance
KW - Circular B-IO
PY - 2025
AN - OPUS4-62990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - A brief survey on open questions about laser-induced periodic surface structures
N2 - The processing of laser-induced periodic surface structures (LIPSS) represents a simple and robust way for the nanostructuring of solids that allows creating a wide range of surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m2/min level, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation aims to identify some unsolved scientific problems related to LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.
T2 - E-MRS Spring Meeting 2022
CY - Online meeting
DA - 30.05.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Industrial applications
KW - Biofilm growth
PY - 2022
AN - OPUS4-54929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zubia Aranburu, Judith
A1 - Cappella, Brunero
A1 - Zabala Eguren, A.
A1 - Buruaga Lamarain, L.
A1 - Aginagalde Lopez, A.
A1 - Bonse, Jörn
A1 - Schwibbert, Karin
T1 - Quantification of the adhesion force of E. coli on Ti via single-cell force spectroscopy
N2 - Antibiotic resistance is a growing global problem which poses a massive threat to human health. Although human activity contributes to the acceleration of the process, bacteria have a self-driven stabilisation mechanism to protect themselves from such and other external threats: biofilm formation. Nonetheless, it is the adhesion of a single bacterial cell to a surface that triggers the formation of such network of biomolecules and microorganisms, as well as its hazardous consequences. The main objective of this work was to quantify the adhesion force of a single E. coli cell on a Ti substrate via the AFM-related single-cell force spectroscopy, with both the cell and the substrate material being of high clinical relevance. A set of 25 x 25 force displacement curves was acquired with a maximum force of 3.2 nN without dwell time, yielding a topography map and an adhesion force map that showed to be correlated. A mean adhesion force of 0.85 ± 0.175 nN was measured and the presence of cell appendages on the bacterial cell wall was verified through individual force-displacement curves. Bacterial viability was assessed after the measurements via live/dead staining.
T2 - XL Congreso Anual de la Sociedad Española de Ingeniería Biomédica CASEIB 2022
CY - Valladolid, Spain
DA - 23.11.2022
KW - Bacteria
KW - Atomic force microscopy
KW - Force distance curve
PY - 2022
SN - 978-84-09-45972-8
SP - 217
EP - 220
AN - OPUS4-57039
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kraft, S.
A1 - Böttcher, Katrin
A1 - Bonse, Jörn
A1 - Schille, J.
A1 - Löschner, U.
A1 - Krüger, Jörg
T1 - Unwanted X-ray emission in ultrashort pulse laser processing: From metallic to biological materials
N2 - X-rays can be generated as an unwanted side effect during ultrashort pulse laser material processing of technical work pieces and even biological samples with laser intensities above 10^13 W/cm^2. First studies demonstrate the need to address this effect in industrial as well as in medical applications. This secondary hazard should be considered in work safety and risk assessment.
T2 - Lasers in Manufacturing 2023 (LiM 2023)
CY - Munich, Germany
DA - 26.06.2023
KW - Ultrashort pulse laser processing
KW - Laser-induced X-ray emission
KW - Secondary hazard
PY - 2023
SP - LiM 2023 - 1
EP - LiM 2023 - 6
PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik e.V. (WLT)
AN - OPUS4-58358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwettmann, K.
A1 - Nytus, N.
A1 - Weigel, Sandra
A1 - Radenberg, M.
A1 - Stephan, D.
T1 - Effects of rejuvenators on bitumen ageing during simulated cyclic reuse: A review
N2 - Single reuse of asphalt is an approved practice, but its success highly depends on restoring the properties of the aged binder. Rejuvenators have become increasingly important for softening the binder because they make it possible to increase the amount of reclaimed asphalt pavement (RAP) while reducing the dependence on virgin bitumen. The vital questions to be investigated are how the rejuvenators affect the ageing properties of bitumen and if rejuvenators offer the possibility of cyclic bitumen reuse. The main objective of this publication is to present the current state of the art regarding the effects of rejuvenators on bitumen ageing. The results of laboratory life cycle simulations indicate that repetitive ageing and rejuvenation processes are possible, but reuse mainly depends on the rejuvenator type and its interaction with the respective bitumen sample. There are rejuvenators that have good rejuvenating properties but accelerate subsequent ageing, which is essential to consider when evaluating a rejuvenator. Bitumen rejuvenated with petroleum-based products, such as aromatic extracts, performs slightly better after subsequent ageing than when rejuvenated with bio-based products. As there are a limited number of studies simulating cyclic bitumen reuse, more studies are necessary to evaluate the general limits of bitumen reuse.
KW - Bitumen
KW - Asphalt
KW - Ageing
KW - Rejuvenator
KW - Recycling
KW - Cyclic reuse
KW - Multiple reuse
PY - 2023
DO - https://doi.org/10.1016/j.resconrec.2022.106776
SN - 0921-3449
VL - 190
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-56963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andrés Arcones, Daniel
A1 - Weiser, M.
A1 - Koutsourelakis, F.-S.
A1 - Unger, Jörg F.
T1 - Evaluation of Model Bias Identification Approaches Based on Bayesian Inference and Applications to Digital Twins
N2 - In recent years, the use of simulation-based digital twins for monitoring and assessment of complex mechanical systems has greatly expanded. Their potential to increase the information obtained from limited data makes them an invaluable tool for a broad range of real-world applications. Nonetheless, there usually exists a discrepancy between the predicted response and the measurements of the system once built. One of the main contributors to this difference in addition to miscalibrated model parameters is the model error. Quantifying this socalled model bias (as well as proper values for the model parameters) is critical for the reliable performance of digital twins. Model bias identification is ultimately an inverse problem where information from measurements is used to update the original model. Bayesian formulations can tackle this task. Including the model bias as a parameter to be inferred enables the use of a Bayesian framework to obtain a probability distribution that represents the uncertainty between the measurements and the model. Simultaneously, this procedure can be combined with a classic parameter updating scheme to account for the trainable parameters in the original model.
This study evaluates the effectiveness of different model bias identification approaches based on Bayesian inference methods. This includes more classical approaches such as direct parameter estimation using MCMC in a Bayesian setup, as well as more recent proposals such as stat-FEM or orthogonal Gaussian Processes. Their potential use in digital twins, generalization capabilities, and computational cost is extensively analyzed.
T2 - 5th ECCOMAS Thematic Conference on Uncertainty Quantificationin Computational Sciences and Engineering
CY - Athen, Greece
DA - 12.06.2023
KW - Model bias
KW - Bayesian Uncertainty Quantification
KW - Digital Twins
KW - Gaussian Processes
KW - Statistical Finite Element Method
PY - 2023
UR - https://2023.uncecomp.org/
SP - 1
EP - 15
AN - OPUS4-58227
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schiebel, J.
A1 - Noack, J.
A1 - Rödiger, S.
A1 - Kammel, A.
A1 - Menzel, Friederike
A1 - Schwibbert, Karin
A1 - Weise, Matthias
A1 - Weiss, R.
A1 - Böhm, A.
A1 - Nitschke, J.
A1 - Elimport, A.
A1 - Roggenbuck, D.
A1 - Schierack, P.
T1 - Analysis of three-dimensional biofilms on different material surfaces
N2 - Biofilms cause complications and high costs in both industry and medicine. Of particular interest are bacterial infections of prosthetic materials, which usually cannot be eliminated due to the high antibiotic resistance known for bacteria forming biofilms. The search for new materials and coatings with lower colonization potential and antibacterial activity is of great importance to reduce biofilm formation. However, there is no standardized procedure to examine the colonization characteristics of bacteria in the Biofilm state in situ. Here, we describe an automated epifluorescence microscopy system for the semi-quantitative analysis of three-dimensional (3D) biofilms on various surfaces. To analyze adherent bacteria, three materials (glass, steel and titanium) were incubated with bacteria in a flow chamber system. After fluorescence staining of the bacteria, automated image capturing, quantification of the bacteria, measurement of the colonized area and determination of the 3D biofilm height were carried out by using novel software.
Furthermore, the materials were examined for their surface topography using white light scanning interferometry. Titanium compared to glass showed a significantly higher number of adherent bacteria.
We argue that this was due to the higher microroughness of titanium. The colonized area was in accordance with the number of adherent bacteria and was also significantly larger on titanium coupons compared to glass. Maximum 3D biofilm height on glass coupons was significantly lower compared to the ones on steel and titanium. This novel method enables the standardized, automated investigation of the colonization with bacteria on different materials. This approach can considerably support the characterization of new material surfaces and their innovative coatings by analyzing the amount of attached Bacteria and thickness of biofilms in situ and eliminates the need of conventional cultivation.
KW - Biofilm
KW - Bacterial adhesion
KW - Biofilm quantification
KW - Automated analysis
PY - 2020
DO - https://doi.org/10.1039/D0BM00455C
SP - 1
EP - 11
PB - Royal Society of Chemistry
AN - OPUS4-50815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Anja
T1 - Laser-processing – a tool to direct biofilm formation
N2 - Using nanofiber-like cell appendages, secreted proteins and sugars, bacteria can establish initial surface contact followed by irreversible adhesion and the formation of multicellular biofilms, often with enhanced resistance towards antimicrobial treatment and established cleaning procedures. On e.g. medical implants, in water supply networks or food-processing industry, biofilms can be a fertile source of bacterial pathogens and are repeatedly associated with persisting, nosocomial and foodborne infections. Nowadays, the emergence of resistances because of extensive usage of antibiotics and biocides in medicine, agriculture and private households have become one of the most important medical challenges with considerable economic consequences. In addition, aggravated biofilm eradication and prolonged cell-surface interaction can lead to increased biodeterioration and undesired modification of industrial and medical surface materials. Various strategies are currently developed, tested, and improved to realize anti-bacterial surface properties through surface functionalization steps avoiding antibiotics.
In this study, contact-less and aseptic large-area short or ultrashort laser processing is employed to generate different surface structures in the nanometer- to micrometer-scale on technical materials such as titanium-alloy and polyethylene terephthalate (PET). The laser processed surfaces were subjected to bacterial colonization studies with Escherichia coli test strains and analyzed with reflected-light and epi-fluorescence microscopy. Depending on the investigated surfaces, different bacterial adhesion patterns were found, ranging from bacterial-repellent to bacterial-attractant effects. The results suggest an influence of size, shape and cell appendages of the bacteria and – above all – the laser-processed nanostructure of the surface itself, emphasizing the potential of laser-processing as a versatile tool to control bacterial surface adhesion.
T2 - International Biodeterioration & Biodegradation Symposium 2021
CY - Online meeting
DA - 06.09.2021
KW - Bacterial adhesion
KW - Biofilm formation
KW - Laser-induced periodic surface structueres (LIPPS)
KW - Laser processing
PY - 2021
UR - https://www.ibbs18.org/programme
AN - OPUS4-53223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishmastnehi, M.
A1 - Van Driessche, A.
A1 - Smales, Glen Jacob
A1 - Moya, A.
A1 - Stawski, Tomasz
T1 - Advanced materials engineering in historical gypsum plaster formulations
N2 - We show how historical gypsum plaster preparation methods affect the microstructure and the wettability properties of the final stucco materials. We reproduced a traditional Persian recipe (Gach-e Koshteh, ~14th century AD), which involves a continuous mechanical treatment during plaster hydration. These samples were compared with a laboratory-replicated historical recipe from Renaissance Italy (Gesso Sottile, ~15th century AD) and contemporary low-strength plaster. The Koshteh recipe induces the formation of gypsum platelets, which exhibit preferential orientation in the plaster bulk. In contrast,
the Italian and low-strength plasters comprise a typical needle-like morphology of gypsum crystals. The platelets in Koshteh expose the more hydrophilic {010} face of gypsum in a much more pronounced manner than needles. Consequently, the Iranian plaster displays enhanced wettability, enabling its direct use for water-based decoration purposes, or as a fine finishing thin layer, without the need of mixing it with a binder material.
Contrary, in Sottile, gypsum crystals are left to equilibrate in large excess of water, which promotes the growth of long needles at the expense of smaller crystals. Typically, such needles are several times longer than those found in a control regular plaster. For this
crystal habit, the total surface of hydrophilic faces is minimized. Consequently, such plaster layers tend to repel water, which can then be used, e.g., as a substrate for oilbased panel paintings. These findings highlight the development of advanced functional materials, by tuning their microtexture, already during the premodern era.
KW - Gypsum
KW - Calcium sulfate
KW - Diffraction
KW - Force microscopy
PY - 2023
DO - https://doi.org/10.1073/pnas.2208836120
VL - 120
IS - 7
SP - 1
EP - 9
PB - National Academy of Sciences of the USA
AN - OPUS4-57219
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Foroutan, F.
A1 - Kyffin, B. A.
A1 - Nikolaou, A.
A1 - Merino-Gutierrez, J.
A1 - Abrahams, I.
A1 - Kanwal, N.
A1 - Knowles, J. C.
A1 - Smith, A. J.
A1 - Smales, Glen Jacob
A1 - Carta, D.
T1 - Highly porous phosphate-based glasses for controlled delivery of antibacterial Cu ions prepared via sol–gel chemistry
N2 - Mesoporous glasses are a promising class of bioresorbable biomaterials characterized by high surface area and extended porosity in the range of 2 to 50 nm. These peculiar properties make them ideal materials for the controlled release of therapeutic ions and molecules. Whilst mesoporous silicate-based glasses (MSG) have been widely investigated, much less work has been done on mesoporous phosphate-based glasses (MPG). In the present study, MPG in the P2O5–CaO–Na2O system, undoped and doped with 1, 3, and 5 mol% of Cu ions were synthesized via a combination of the sol–gel method and supramolecular templating. The non-ionic triblock copolymer Pluronic P123 was used as a templating agent. The porous structure was studied via a combination of Scanning Electron Microscopy (SEM), Small-Angle X-ray Scattering (SAXS), and N2 adsorption–desorption analysis at 77 K. The structure of the phosphate network was investigated via solid state 31P Magic Angle Spinning Nuclear Magnetic Resonance (31P MAS-NMR) and Fourier Transform Infrared (FTIR) spectroscopy. Degradation studies, performed in water via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), showed that phosphates, Ca2+, Na+ and Cu ions are released in a controlled manner over a 7 days period. The controlled release of Cu, proportional to the copper loading, imbues antibacterial properties to MPG. A significant statistical reduction of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacterial viability was observed over a 3 days period. E. coli appeared to be more resistant than S. aureus to the antibacterial effect of copper. This study shows that copper doped MPG have great potential as bioresorbable materials for controlled delivery of antibacterial ions.
KW - Bioresorbable Biomaterials
KW - Mesoporous phosphate-based glasses
KW - Synthesis
KW - Degradation studies
KW - X-ray scattering
KW - MOUSE
KW - Antibacterial properties
KW - Aantimicrobial
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578101
DO - https://doi.org/10.1039/D3RA02958A
VL - 13
IS - 29
SP - 19662
EP - 19673
PB - Royal Society of Chemistry
AN - OPUS4-57810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, W.
A1 - Schweins, R.
A1 - Nöcker, B.
A1 - Kohlbrecher, J.
A1 - Smales, Glen Jacob
A1 - Huber, K.
T1 - Comparative study of the co-assembly behaviour of 3-chloro-4-hydroxy-phenylazo dyes with DTAB
N2 - The co-assembly of three one-fold negatively charged 3-chloro-4-hydroxy-phenylazo dyes (Yellow, Blue and Red) with the cationic surfactant dodecyltrimethylammoniumbromide (DTAB) was studied to probe dye–DTAB binding stoichiometry and assembly morphology. For each dye, phase separation was observed above a given dye : DTAB ratio with the ratio depending on the dye. While Yellow and DTAB showed liquid/liquid phase separation above Yellow : DTAB = 1 : 1.67, crystalline dye–DTAB complexes were observed for Blue–DTAB and Red–DTAB above Blue : DTAB = 1 : 2.56 and Red : DTAB = 1 : 2.94 respecively. In homogeneous solution, UV/vis spectroscopic investigations suggest stochiometries of Yellow : DTAB = 1 : 2, Blue : DTAB = 1 : 3 and Red : DTAB = 1 : 4. It was concluded, that Yellow exhibits the highest dye : DTAB binding stoichiometry in both, dye–surfactant complexes in the 2-phase region and in solution, whereas the lowest dye : DTAB binding stoichiometry was observed for Red–DTAB in both cases. The observed stoichiometries are inversely correlated to the impact dye addition has on the morphology of DTAB micelles. Generally, addition of dye to DTAB micelles leads to a reduction in spontaneous curvature of these micelles and to the formation of triaxial ellipsoidal or cylindrical micelles from oblate ellipsoidal DTAB micelles. At a DTAB concentration of 30 mM and a dye concentration of 5 mM, this effect was most pronounced for Red and least pronounced for Yellow, whilst Blue showed an intermediate effect.
KW - Dye
KW - DTAB
KW - SAXS
KW - Small-angle X-ray scattering
KW - X-ray scattering
KW - Data analysis
KW - Micelle
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576978
DO - https://doi.org/10.1039/D3SM00501A
SN - 1744-683X
VL - 19
IS - 24
SP - 4588
EP - 4598
PB - Royal Society of Chemistry
AN - OPUS4-57697
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - What’s that beyond the grasslands? Expanding your world view via wide-range X-ray scattering
N2 - This talk introduces the expanded view that comes from wide-range X-ray scattering investigations.
Compared to X-ray diffraction studies alone, the additional angular range of this technique provides information on the larger structural dimensions present in your samples. This allows for the extraction of information on the size and size distribution of nanostructural components, such as nanoparticles, nanovoids, and any other structure exhibiting an electron density contrast.
The talk introduces the technique, the MOUSE instrument used for these investigations, and provides several real-world examples of its uses. The audience is invited to choose which examples captures their interest from a range of options, in the latter segment of the talk.
T2 - ECS8: European Crystallography School 2023
CY - Berlin, Germany
DA - 18.06.2023
KW - X-ray scattering
KW - Introduction
KW - Fourier transforms
KW - Nanostructure investigation
KW - Instrument automation
KW - MOUSE
PY - 2023
AN - OPUS4-57769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chambers, Aaron
T1 - Using an automation assisted Synthesis to produce functionalized ZIF-8 nanoparticles for effective composite formation
N2 - This presentation details the progress of the PhD project so far. It discuss the background of the project such as what is a MOF, ZIF and ZIF composite before discussing the aims and approaches for the work. Then the presentation looks at the data obtained so far and the techniques/syntheses used.
T2 - Postgraduate Researcher Symposium, University of Birmingham
CY - Online meeting
DA - 27.06.2023
KW - Automation
KW - Nanoparticles
KW - ZIF-8
KW - Composites
PY - 2023
AN - OPUS4-57867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heyn, A.
A1 - Kotula, Stefan
A1 - Ebell, Gino
A1 - Babutzka, M.
T1 - Results of a Round Robin Test for the Determination of Polarization Resistances on Differently Weathered Zinc Samples Using Gel Electrolytes
N2 - This article presents the results of a round robin test throughout Germany with 19 participating institutions. Corrosion productlayer resistances (RL ) were determined on two differently weathered pure zinc samples and a sample activated with NaOH bymeans of electrochemical measurement of the linear polarization resistance (LPR) using agar‐based gel electrolytes. The roundrobin test was organized by the Bundesanstalt für Materialforschung und ‐prüfung (BAM) in Berlin. The measurements werecarried out by the participants in the period from May to July 2021. The results are summarized in this article comprising anassessment of the reproducibility and repeatability of the measurements. The methodology is suitable for distinguishing zincsurfaces after exposure to different atmospheres based on the corrosion product layer resistances (RL). In addition, possibleproblems in the application of the method were identified, and solutions for improving reproducibility and repeatability arediscussed. The results and knowledge from the round robin test are incorporated into a new test standard (DIN 50023:2024‐07)for this measurement method
KW - Corrosion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630546
DO - https://doi.org/10.1002/maco.202414696
SN - 1521-4176
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-63054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ebell, Gino
T1 - Exposure Site 41 Berlin
N2 - The United Nations Educational, Social and Cultural Organization (UNESCO) is establishing a project with the objective of investigating the role of air pollution in the acceleration of ongoing corrosion processes and the resulting corrosion intensity. Consequently, since the early 1980s, research has been conducted on 60 different exposure sites. The Bundesumweltamt has mandated the BAM to oversee a designated test sites, a responsibility that the BAM has accepted since 2024. The presentation will provide a visual representation of the newly constructed test site, in addition to the inaugural results of 2024.
T2 - UNESCO Materials RISE Meeting
CY - Prague, Czech Republic
DA - 05.05.2025
KW - Korrosion
KW - Corrosion
PY - 2025
AN - OPUS4-63080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Delgado Arroyo, Diego
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Boerner, Andreas
A1 - Rhode, Michael
A1 - Lindner, T.
A1 - Preuß, B.
A1 - Lampke, T.
T1 - Influence of Milling Conditions on AlxCoCrFeNiMoy Multi-Principal-Element Alloys
N2 - Multi-Principal-Element or High-Entropy Alloys (MPEAs/HEAs) have gained increasing interest in the past two decades largely due to their outstanding properties such as superior mechanical strength and corrosion resistance. However, research studies on their processability are still scarce. This work assesses the effect of different machining conditions on the machinability of these novel alloys, with the objective of advancing the introduction of MPEA systems into industrial applications. The present study focuses on the experimental analysis of finish-milling conditions and their effects on the milling process and resulting surface finish of CoCrFeNi, Al0.3CoCrFeNi and Al0.3CoCrFeNiMo0.2 alloys fabricated via Spark Plasma Sintering. Ball-nose-end milling experiments have been carried out various milling parameters such as cutting speed, feed per cutting edge, and ultrasonic assistance. In situ measurements of cutting forces and temperature on the tool edge were performed during the experiments, and surface finish and tool wear were analyzed afterwards. The results exhibited decreasing cutting forces by means of low feed per cutting edge and reduced process temperatures at low cutting speed, with the use of ultrasonic-assisted milling. It was shown that the machinability of these modern alloys through conventional, as well as modern machining methods such as ultrasonic-assisted milling, is viable, and common theories in machining can be transferred to these novel MPEAs.
KW - Multi-principal element alloys
KW - Finish milling
KW - Spark plasma sintering
KW - Ultrasonic-assisted milling
KW - Microstructure characterization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572990
DO - https://doi.org/10.3390/coatings13030662
VL - 13
IS - 3
SP - 1
EP - 18
PB - MDPI (Multidisciplinary Digital Publishing Institute)
CY - Basel (CH)
AN - OPUS4-57299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buzolin, R.H.
A1 - Richter, Tim
A1 - Pixner, F.
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Enzinger, N.
T1 - Microstructure and texture characterisation of friction stir welded CoCrNi and CoCrFeMnNi multi-principle element alloys
N2 - This work investigates the microstructure formed in friction stir welds of FCC alloys, focused on two multiprincipal alloys: a CoCrFeMnNi high-entropy alloy (HEA) and a CoCrNi medium-entropy alloy (MEA). A commercial stainless steel AISI 304 is used for comparison. The largest nugget was formed in the MEA, while the smallest was formed in the HEA. Grain refinement occurs in the stirred zone in all welds. Discontinuous dynamic recrystallisation is the predominant restoration mechanism during friction stir welding of the three investigated alloys. A sharp decrement in the Σ3 boundary fraction occurs in the stirred zone of the AISI 304 and HEA welds, while comparable values with the base metal are found for the MEA weld. The peak in the maximum index of crystallographic texture is observed on the advancing side of the stirred zone of the AISI 304 weld. A strong <001> θ-fibre texture is formed in the advancing side of the nugget in the AISI 304 from a well-established {123} <634> S-type texture in the base metal. Multiple crystallographic texture components without specific fibres are identified in most regions of the welds, indicating the complex shear path history during friction stir welding.
KW - Microstructure
KW - Multiple principal element alloy
KW - Friction stir welding
KW - Electron backscattered diffraction
KW - Crystallographic texture
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572987
DO - https://doi.org/10.1016/j.mtcomm.2023.105870
VL - 35
SP - 1
EP - 14
PB - Elsevier Ltd.
CY - Amsterdam (NL)
AN - OPUS4-57298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, F.
A1 - Ren, H.
A1 - Zheng, M.
A1 - Shao, X.
A1 - Dai, T.
A1 - Wu, Y.
A1 - Tian, L.
A1 - Liu, Y.
A1 - Liu, B.
A1 - Günster, Jens
A1 - Liu, Y.
A1 - Liu, Y.
T1 - Development of biodegradable bioactive glass ceramics by DLP printed containing EPCs/BMSCs for bone tissue engineering of rabbit mandible defects
N2 - Bioactive glass ceramics have excellent biocompatibility and osteoconductivity; and can form direct chemical bonds with human bones; thus, these ceramic are considered as “Smart” materials. In this study, we develop a new type of bioactive glass ceramic (AP40mod) as a scaffold containing Endothelial progenitor cells (EPCs) and Mesenchymal stem cells (BMSCs) to repair critical-sized bone defects in rabbit mandibles. For in vitro experiments:
AP40mod was prepared by Dgital light processing (DLP) system and the optimal ratio of EPCs/BMSCs was screened by analyzing cell proliferation and ALP activity, as well as the influence of genes related to osteogenesis and angiogenesis by direct inoculation into scaffolds. The scaffold showed suitable mechanical properties, with a Bending strength 52.7 MPa and a good biological activity. Additionally, when EPCs/BMSCs ratio were combined at a ratio of 2:1 with AP40mod, the ALP activity, osteogenesis and angiogenesis were significantly increased. For in vivo experiments: application of AP40mod/EPCs/BMSCs (after 7 days of in vitro spin culture) to repair and reconstruct critical-sized mandible defect in rabbit showed that all scaffolds were successfully accurately implanted into the defect area. As revealed by macroscopically and CT at the end of 9 months, defects in the AP40mod/EPCs/BMSCs group were nearly completely covered by normal bone and the degradation rate was 29.9% compared to 20.1% in the AP40mod group by the 3D reconstruction. As revealed by HE and Masson staining analyses, newly formed blood vessels, bone marrow and collagen maturity were significantly increased in the AP40mod/EPCs/BMSCs group compared to those in the AP40mod group. We directly inoculated cells on the novel material to screen for the best inoculation ratio. It is concluded that the AP40mod combination of EPCs/BMSCs is a promising approach for repairing and reconstructing large load bearing bone defect.
KW - Three-dimensional Bone tissue engineering
KW - Endothelial progenitor cell
KW - Bone marrow-derived mesenchymal stem cell
KW - Bioactive glass scaffold
PY - 2020
DO - https://doi.org/10.1016/j.jmbbm.2019.103532
SN - 1751-6161
VL - 103
SP - 103532
EP - 103532
PB - Elsevier Ltd.
AN - OPUS4-50491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - In situ Messung chemischer Konzentrationen im Schmelzbad von Duplexstählen während des WIG-Schweißens
N2 - Die Kombination aus hoher Korrosionsbeständigkeit und guten mechanischen Eigenschaften von Duplexstählen (DSS) ist auf ihre chemische Zusammensetzung und das ausgewogene Phasenverhältnis von Ferrit (α) und Austenit (γ) zurückzuführen.
Viele industrielle Anwendungen erfordern eine stoffschlüssige Verbindung von DSS. Das Wolfram-Inertgas-Schweißen (WIG) ist relativ einfach zu handhaben, benötigt nur wenig Platz und ermöglicht ein automatisiertes Schweißen, mit sehr hoher Reproduzierbarkeit und ist daher hervorragend zum Schweißen von DSS.
Während der Erstarrung dieser Dualphasenstähle kann es zu kritischen Phasenverhältnissen von α und γ kommen, was zu Erstarrungsrissen, Korrosionsanfälligkeit, geringerer Duktilität und kritischen Festigkeitswerten führt. Um die gewünschten Werkstoffeigenschaften zu erhalten, muss daher die α/γ-Verteilung zuverlässig vorhergesagt werden. Dies geschieht in der Regel mit Hilfe des WRC1992-Diagramms. Die Vorhersagegenauigkeit des Ferritgehalts in diesem Diagramm ist jedoch meist nicht genau genug und muss daher optimiert werden. Daher ist es notwendig, selbst kleinste Veränderungen in der chemischen Zusammensetzung des Schweißguts idealerweise während des Schweißens zu überwachen. Dies wird in diesen Experimenten mit Hilfe der laser-induzierten Plasmaspektroskopie (LIBS) durchgeführt. Ein großer Vorteil dieser Technik ist die hochgenaue zeit- und ortsaufgelöste Messung der chemischen Zusammensetzung während des Schweißens. In vorherigen Arbeiten wurde bereits die chemische Zusammensetzung im Schweißgut und der WEZ quantifiziert. In der präsentierten Untersuchung wird der Einfluss einzelner Elemente, wie Nb und Cu, auf das resultierende Schweißmikrogefüge untersucht.
T2 - BMDK der Universität Magdeburg
CY - Magdeburg, Germany
DA - 08.11.2023
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Calibration free
PY - 2023
AN - OPUS4-58777
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zekhnini, Khalid
T1 - Corrosion at metallic offshore constructions – Bundesanstalt für Materialforschung und -prüfung (BAM)
N2 - In the maritime context of offshore operation, corrosion, in combination with the materials used, poses a particular challenge to ensure safe operation over long indefinite periods and to minimise susceptibility to failure. Until today, only a few corrosion protection systems have proven themselves for the interaction of efficiency, installation, and maintenance in the offshore sector. In addition, available corrosion test methods sometimes have major deficits about conclusions of the durability. Therefore, there is more research and development needed.
The flagship project H2Mare of the Federal Ministry of Education and Research aims to enable the production of green hydrogen and PtX products at high seas. Research is being driven forward by the partners in four individual projects, where BAM is involved in two.
In PtX-Wind, major kinds of corrosion attacks at offshore constructions are characterized and investigated, and suitable corrosion protection measures determined. In TransferWind, attention focusses on transferring scientific results into standardization.
This poster at the H2Mare Conference 2023 presents an overview of the investigation methods and contribution of the department “Corrosion and Corrosion Protection”.
T2 - H2Mare Conference 2023
CY - Frankfurt/Main, Germany
DA - 12.06.2023
KW - Atmospheric Corrosion
KW - Sea Water
KW - Corrosion Testing
KW - Offshore
KW - Laboratory Container
KW - Corrosion protecting system
PY - 2023
AN - OPUS4-57838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Residual stresses in near-component specimens of a high and a medium entropy alloy due to tig and friction stir welding
N2 - The new alloying concept of multi-element systems with defined entropy (HEA - High Entropy Alloy or MEA - Medium Entropy Alloy) is gaining increasing importance in materials research. Significantly improved properties or combinations of properties are shown by some HEA/MEA-systems, which have the potential to substitute conventional alloys such steels and are therefore promising for a wide range of applications, e.g., overcome of the trade-off between high strength and ductility. Thus, primarily the production and resulting microstructures of HEA as well as properties have been investigated so far. Furthermore, processing is a main issue to transfer HEA systems from the laboratory to real components, e.g., for highly stressed components. Since welding is the most important joining process for metals, it is crucial to investigate the influence of welding processing on these material properties to guarantee component integrity. Welding leads to residual stresses, which significantly affect the component integrity. Only a very few studies on the effect of welding on residual stresses in HEA and MEA weld joints are available so far. Hence, the focus of this study is the residual stress formation and distribution in a CoCrFeMnNi HEA and ternary CoCrNi MEA using two different welding processes: Tungsten Inert Gas (TIG) welding and soldi-state Friction Stir Welding (FSW). As a pathway for application of HEA in this investigation for the first time residual stress analyses in realistic near-component specimens were performed. The residual stresses were determined by X-ray diffraction (XRD) on the surfaces of top and root weld side. The results were correlated with the local welding microstructures. The results show that both FSW and TIG generate significant tensile residual stresses on the weld surfaces in and transverse to the welding direction. In the case of FSW of the CoCrFeMnNi HEA, the longitudinal residual stresses are in the range of the yield strength of approx. 300 MPa in the weld zone.
T2 - OVGU-Kolloquium (BMDK des IWF)
CY - Online meeting
DA - 19.05.2022
KW - High Entropy Alloy
KW - Welding
KW - Residual stresses
KW - Microstructure
PY - 2022
AN - OPUS4-56671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Diese, Marcel
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
T1 - Characterization of cracking phenomena in TIG welds of high and medium entropy alloy
N2 - Multi-element systems with defined entropy (HEA - High Entropy Alloy or MEA - Medium Entropy Alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcome of the trade-off between high strength and ductility. Thus, the synthesis, the resulting microstructures, and properties of HEA have been primarily investigated so far. In addition, processing is crucial to achieve a transfer of potential HEA/MEA materials to real applications, e.g. highly stressed components. Since fusion welding is the most important joining process for metals, it is of vital importance to investigate the weldability of these materials. However, this has rarely been the subject of research up to date. For that reason, in this work the weldability depending on the surface preparation of a CoCrFeMnNi-HEA and a CoCrNi-MEA for TIG welding is investigated. The fusion welding of longer plates is described here for the first time for the CoCrNi alloy. The welds of both materials showed distinct formation of cracks in the heat affected zone (HAZ). Optical and scanning electron microscopy analysis clearly confirmed an intergranular fracture topography. But based on the results, the crack mechanism cannot be conclusively clarified as either a liquid metal embrittlement (LME) or hot cracking like liquid film separation occurred.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Online meeting
DA - 21.10.2021
KW - High Entropy Alloy
KW - TIG welding
KW - Cracking
PY - 2021
AN - OPUS4-53607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Z.
A1 - Villa Santos, C.
A1 - Legrand, A.
A1 - Haase, F.
A1 - Hara, Y.
A1 - Kanamori, K.
A1 - Aoyama, T.
A1 - Urayama, K.
A1 - Doherty, C. M.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Colon, Y. J.
A1 - Furukawa, S.
T1 - Multiscale structural control of linked metal–organic polyhedra gel by aging-induced linkage-reorganization
N2 - Assembly of permanently porous metal–organic polyhedra/cages (MOPs) with bifunctional linkers leads to soft supramolecular networks featuring both porosity and processability. However, the amorphous nature of such soft materials complicates their characterization and thus limits rational structural control. Here we demonstrate that aging is an effective strategy to control the hierarchical network of supramolecular gels, which are assembled from organic ligands as linkers and MOPs as junctions. Normally, the initial gel formation by rapid gelation leads to a kinetically trapped structure with low controllability. Through a controlled post-synthetic aging process, we show that it is possible to tune the network of the linked MOP gel over multiple length scales. This process allows control on the molecular-scale rearrangement of interlinking MOPs, mesoscale fusion of colloidal particles and macroscale densification of the whole colloidal network. In this work we elucidate the relationships between the gel properties, such as porosity and rheology, and their hierarchical structures, which suggest that porosity measurement of the dried gels can be used as a powerful tool to characterize the microscale structural transition of their corresponding gels. This aging strategy can be applied in other supramolecular polymer systems particularly containing kinetically controlled structures and shows an opportunity to engineer the structure and the permanent porosity of amorphous materials for further applications.
KW - SAXS
KW - Metal-organic polyhedra
KW - Structural control
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532309
DO - https://doi.org/10.1039/d1sc02883a
SN - 1478-6524
SN - 1742-2183
VL - 12
IS - 38
SP - NIL_1
EP - NIL_9
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-53230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pallasch, Sebastian M.
A1 - Bhosale, Manik
A1 - Smales, Glen Jacob
A1 - Schmidt, Caroline
A1 - Riedel, Sibylle
A1 - Zhao-Karger, Zhirong
A1 - Esser, Birgit
A1 - Dumele, Oliver
T1 - Porous Azatruxene Covalent Organic Frameworks for Anion Insertion in Battery Cells
N2 - Covalent organic frameworks (COFs) containing well-defined redox-active groups have become competitive materials for next-generation batteries. Although high potentials and rate performance can be expected, only a few examples of p-type COFs have been reported for charge storage to date with even fewer examples on the use of COFs in multivalent ion batteries. Herein, we report the synthesis of a p-type highly porous and crystalline azatruxene-based COF and its application as a positive electrode material in Li- and Mg-based batteries. When this material is used in Li-based half cells as a COF/carbon nanotube (CNT) electrode, a discharge potential of 3.9 V is obtained with discharge capacities of up to 70 mAh g−1 at a 2 C rate. In Mg batteries using a tetrakis(hexafluoroisopropyloxy)borate electrolyte, cycling proceeds with an averge discharge voltage of 2.9 V. Even at a fast current rate of 5 C, the capacity retention amounts to 84% over 1000 cycles.
KW - COFs
PY - 2024
DO - https://doi.org/10.1021/jacs.4c04044
VL - 146
IS - 25
SP - 17318
EP - 17324
PB - Journal of the American Chemical Society
AN - OPUS4-60419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kool, L.
A1 - Dekker, F.
A1 - Bunschoten, A.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Velders, A. H.
A1 - Saggiomo, V.
T1 - Gold and silver dichroic nanocomposite in the quest for 3D printing the Lycurgus cup
N2 - The Lycurgus cup is an ancient glass artefact that shows dichroism as it looks green when a white light is reflected on it and a red colouring appears when a white light is transmitted through it. This peculiar dichroic effect is due to silver and gold nanoparticles present in the glass. In this research we show the synthesis of dichroic silver nanoparticles and their embedding in a 3D printable nanocomposite. The addition of gold nanoparticles to the silver nanoparticle composite, gave a 3D printable nanocomposite with the same dichroism effect of the Lycurgus cup.
KW - SAXS
KW - Au
KW - Ag
KW - Nanocomposite
KW - 3D printing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501831
DO - https://doi.org/10.3762/bjnano.11.2
SP - 16
EP - 23
AN - OPUS4-50183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hunter, R. D.
A1 - Rowlandson, J. L.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Ting, V. P.
A1 - Kulak, A.
A1 - Schnepp, Z.
T1 - The effect of precursor structure on porous carbons produced by iron-catalyzed graphitization of biomass
N2 - This paper reports a systematic study into the effect of different biomass-derived precursors on the structure and porosity of carbons prepared via catalytic graphitization. Glucose, starch and cellulose are combined with iron nitrate and heated under a nitrogen atmosphere to produce Fe3C nanoparticles, which catalyze the conversion of amorphous carbon to graphitic nanostructures. The choice of organic precursor provides a means of controlling the catalyst particle size, which has a direct effect on the porosity of the material. Cellulose and glucose produce mesoporous carbons, while starch produces a mixture of micro- and mesopores under the same conditions and proceeds via a much slower graphitization step, generating a mixture of graphitic nanostructures and turbostratic carbon. Porous carbons are critical to energy applications such as batteries and electrocatalytic processes. For These applications, a simple and sustainable route to those carbons is essential. Therefore, the ability to control the precise structure of a biomass-derived carbon simply through the choice of precursor will enable the production of a new generation of energy materials.
KW - SAXS
KW - Porous carbons
KW - Graphitization
KW - Iron nanoparticles
KW - Catalysis
KW - Gas sorption
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515531
DO - https://doi.org/10.1039/d0ma00692k
VL - Royal Society of Chemistry
SP - 1
EP - 11
AN - OPUS4-51553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallau, Wilma
A1 - Recknagel, Christoph
A1 - Smales, Glen Jacob
T1 - Structural silicone sealants after exposure to laboratory test for durability assessment
N2 - During the service life of structural sealant glazing (SSG) facades, the loadbearing capacity of the silicone bonds needs to be guaranteed. Laboratory Tests can assess the durability of SSG-systems based on mechanical characteristics of the bond after simultaneous exposure to both climatic and mechanical loads.
This article studies how the material characteristics of two common structural sealants are affected by laboratory and field exposure. Dynamic mechanical Analysis (DMA) confirms a reduction in the dynamic modulus of exposed Silicone samples. Results from thermogravimetric analysis, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and small-angle X-ray scattering/wide-angle X-ray scattering show differences between the two sealants and indicate no/minor changes in the composition and morphology of the laboratory and field exposed sealants. Mechanical characterization methods, such as DMA, and tensile and shear testing of the structural bond, are shown to be sensitive toward the combined climatic and mechanical loadings, and are hence suitable for studying degradation mechanisms of structural sealants.
KW - Aging
KW - Analytical methods
KW - Fatigue
KW - Silicone elastomer
KW - Structural sealant glazing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527217
DO - https://doi.org/10.1002/app.50881
VL - 138
IS - 35
SP - 50881
PB - Wiley
AN - OPUS4-52721
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - How to manage a modern X-ray scattering lab – a modest example
N2 - Introduction
A good laboratory organization can help address the reproducibility crisis in science, and easily multiply the scientific output of a laboratory, while greatly elevating the quality of the measurements. We have demonstrated this for small- and wide-angle X-ray scattering in the MOUSE project (Methodology Optimization for Ultrafine Structure Exploration). In the MOUSE, we have combined: a) a comprehensive laboratory workflow with b) a heavily modified, highly automated X-ray scattering instrument. This combination allows us to collect fully traceable scattering data, with a well-documented data flow (akin to what is found at the more automated beamlines). With two full-time researchers, the lab collects and interprets thousands of datasets, on hundreds of samples for dozens of projects per year, supporting many users along the entire process from sample selection and preparation, to the analysis of the resulting data.
While these numbers do not light a candle to those achieved by our hardworking compatriots at the synchrotron beamlines, the laboratory approach does allow us to continually modify and fine-tune the integral methodology. So for the last three years, we have incorporated e.g. FAIR principles, traceability, automated processing, data curation strategies, as well as a host of good scattering practices into the MOUSE system. We have concomitantly expanded our purview as specialists to include an increased responsibility for the entire scattering aspect of the resultant publications. This ensures full exploitation of the data quality, whilst avoiding common pitfalls.
Talk scope
This talk will present the MOUSE project as implemented to date, and will introduce foreseeable upgrades and changes. These upgrades include better pre-experiment sample scattering predictions to filter projects on the basis of their suitability, exploitation of the measurement database for detecting long-term changes and automated flagging of datasets, extending the measurement range through an Ultra-SAXS module, and enhancing MC fitting with sample scattering simulations for better matching of odd-shaped scatterers.
T2 - 2021 joint virtual meeting of the African Light Source (AfLS), the African Physical Society (AfPS), and Pan African Conference on Crystallography (ePCCr)
CY - Online meeting
DA - 15.11.2021
KW - X-ray scattering
KW - MOUSE
KW - Instrumentation
KW - SAXS
KW - Methodology
KW - Laboratory management
KW - Databases
KW - Data management
KW - Data catalog
KW - Scicat
PY - 2021
UR - https://events.saip.org.za/event/170/contributions/7619/
AN - OPUS4-53811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Better with Scattering Part 1: Fundamentals of X-ray scattering
N2 - Today's speaker is a young scientist whose research on all aspects of small-angle scattering has taken him from his birthplace in Netherlands, to Denmark, Japan and now Germany. His research has led to a new method and software for scattering pattern analysis, a comprehensive set of data corrections together with the Diamond Light Source, and a new ultra-SAXS plug-in instrument.
For the last few years, he has been working on a comprehensive and universal methodology to get high-quality X-ray scattering measurements for any sample, using his new instrument at the institute. This instrument has now been heavily modified both in hardware and software, so that it can deliver better data.
These developments are always driven by interesting collaborations with materials researchers and other scientists. As a joint member he has published works on a wide variety of materials, including self-assembled structures in liquids, composite materials and porous carbon catalysts.
He has also been very active in outreach, for example by co-organizing an online lecture series called ‘#the Light Stuff’ on scattering and diffraction, running the ‘looking at nothing’ weblog, hosting a yearly introductory scattering course, and he has many scattering-related lectures available on YouTube.
Our distinguished speaker is Dr. Brian Richard Pauw from the Federal Institute for Materials Research and Testing in Germany. I proudly invite Dr. Pauw to begin his talk
T2 - The first training course on the principles & application of X-ray scattering in nanomaterials
CY - Online meeting
DA - 28.04.2021
KW - X-ray scattering
KW - Methodology
KW - MOUSE
KW - Introduction
KW - Theory
PY - 2021
AN - OPUS4-53275
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - More of the same, please! Standardizing a perfectionist X-ray Scattering methodology for labs and synchrotrons
N2 - After a colleague sent me a more useful measurement from a laboratory instrument than what I could get from the beamline, I knew it was time to reassess my life's choices. Over the course of several subsequent post-doc and permanent positions around lab instruments, I managed to refine a flexible, comprehensive methodology for data collection, correction and analysis which can be applied to many X-ray scattering investigations at the lab and at the synchrotron. With the help of friends at round places, this methodology was implemented and put into production, and has been delivering high-quality data since then. Now, we have almost all possible data corrections (for X-ray scattering) implemented, and are improving the hardware to deliver higher-quality metadata to enable the corrections to be performed to a higher accuracy.
Simultaneously, we have set up a mini-large facility at BAM with the MAUS, the Multi-scale Analyzer for Ultrafine Structures. The MAUS combines the freedom of a laboratory instrument, with the spectrum of users of a beamline: besides measuring our own samples, and performing our own machine and methodology developments, we have opened this instrument for collaboration with fellow scientists from within BAM and from external institutes and universities. Here, we provide a comprehensive support for these collaborations, guiding the user from concept to sample selection, to interpretation and analysis. In 2019, we have supported over 30 different projects this way, leading to seven co-authored publications involving the MAUS in that year alone. As the MAUS uses the latest iteration of our comprehensive measurement methodology, the data quality is unmatched by any other lab instrument, and fully traceable to boot.
The freedom of the laboratory allows for more proof-of-principle experimentation than what is possible at the synchrotron. Therefore, the MAUS provides a good first (and sometimes final) step towards many experimental materials science investigations, nicely complementing the capabilities of the synchrotron. If and when more flux is needed, the step to the synchrotron is now smaller than ever, in particular with the same method
T2 - Symposium on large scale facilities
CY - BAM, Berlin, Germany
DA - 09.03.2020
KW - Small angle scattering
KW - Methodology
KW - X-ray scattering
PY - 2020
AN - OPUS4-51014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Smales, Glen Jacob
T1 - Following the formation of zeolites and MOFs in-situ
N2 - Porous materials are of a great interest due to their ability to interact with ions and molecules not only on their surface but throughout their bulk. Porous materials are conventionally used in applications; such as ion exchange, adsorption/separation and in catalysis, exploiting the huge internal surface area of highly ordered porous materials. [1, 2] The ability for these materials to succeed, in a particular field, is dependent greatly upon the uniformity of the shape and size of the pores within the material. However, despite how well we are able to understand the stability of 3-D frameworks in crystalline or polycrystalline zeolites and ZIFs, there still remains major limitations in fully understanding the synthetic mechanisms occurring prior to their formation. [3, 4] Though the syntheses of a wide variety of porous solids are already well established, their formation mechanisms continue to be of great interest to both academic and industrial communities, with the thought that with greater understanding of the formation of these solids can lead to their rational design. By obtaining a better knowledge of the underlying nucleation mechanisms, it can allow for increased predictability of new structures and in addition can reveal valuable information regarding the particle dimensions aiding in controlling particle morphology and size.
Small-angle and wide-angle X-ray scattering (SAXS/WAXS) are ideal techniques for determining morphological changes in-situ, where the shape, size and crystallinity can be followed at a high temporal resolution, and when these techniques are deployed alongside complimentary techniques, such as ex-situ microscopy, a great deal of information on the formation of materials can be obtained. The above-mentioned methodologies were utilised to study the formation of Silicalite-1 from multiple silica sources to obtain a detailed picture of the formation as a whole, including the formation of intermediate species (Image 1 show the in-situ SAXS data collected from the formation of Silicalite-1 from tetraethyl orthosilicate).
In-situ SAXS/WAXS studies were also utilized to observe the formation of ZIF-8 alongside in-situ X-ray absorption spectroscopy (XAS) experiments to probe both the morphological changes, as well as any changes occurring to the local structure during synthesis (Image 2 show the in-situ SAXS data collected from the formation of ZIF-8). These timeresolved in-situ studies have been utilised to follow changes in crystallinity and crystallite size, whilst also providing valuable information on the formation of intermediate species, the nucleation of crystalline ZIFs, and their subsequent growth.
References:
[1] M E Davis. Nature, 417(6891):813–21, 2002
[2] S T Meek, J A Greathouse, M D Allendorf, Advanced Materials, 23 (2): 249-267, 2011
[3] J Grand, H Awala, CrystEngComm,18 (5): 650–664, 2016
[4] M J V Vleet, T Weng, X Li, J R Schmidt. Chem.Rev.,118 (7): 3681–3721, 2018
T2 - 8th Conference of the Federation of European Zeolite Associations (FEZA 2021)
CY - Online meeting
DA - 05.07.2021
KW - SAXS
KW - Zeolites
KW - MOFs
KW - In situ
PY - 2021
AN - OPUS4-53187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - The Meticulous Approach: Fully traceable X-ray scattering data via a comprehensive lab methodology
N2 - To find out if experimental findings are real, you need to be able to repeat them. For a long time, however, papers and datasets could not necessarily include sufficient details to accurately repeat experiments, leading to a reproducibility crisis. It is here, that the MOUSE project (Methodology Optimization for Ultrafine Structure Exploration) tries to implement change – at least for small- and wide-angle X-ray scattering (SAXS/WAXS).
In the MOUSE project, we have combined: a) a comprehensive laboratory workflow with b) a heavily modified, highly automated Xenocs Xeuss 2.0 instrumental component. This combination allows us to collect fully traceable scattering data, with a well-documented data flow (akin to what is found at the more automated beamlines). With two full-time researchers, the lab collects and interprets thousands of datasets, on hundreds of samples for dozens of projects per year, supporting many users along the entire process from sample selection and preparation, to the analysis of the resulting data.
While these numbers do not light a candle to those achieved by our hardworking compatriots at the synchrotron beamlines, the laboratory approach does allow us to continually modify and fine-tune the integral methodology. So for the last three years, we have incorporated e.g. FAIR principles, traceability, automated processing, data curation strategies, as well as a host of good scattering practices into the MOUSE system. We have concomitantly expanded our purview as specialists to include an increased responsibility for the entire scattering aspect of the resultant publications, to ensure full exploitation of the data quality, whilst avoiding common pitfalls.
This talk will discuss the MOUSE project1 as implemented to date, and will introduce foreseeable upgrades and changes. These upgrades include better pre-experiment sample scattering predictions to filter projects on the basis of their suitability, exploitation of the measurement database for detecting long-term changes and automated flagging of datasets, and enhancing MC fitting with sample scattering simulations for better matching of odd-shaped scatterers.
T2 - S4SAS
CY - Online meeting
DA - 01.09.2021
KW - X-ray scattering
KW - Methodology
KW - MOUSE
KW - Data organization
KW - Automation
KW - Traceability
PY - 2021
AN - OPUS4-53273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
T1 - Complete set of raw and processed datasets, as well as associated Jupyter notebooks for analysis, associated with manuscript entitled: "The MOUSE project: a practical approach for obtaining traceable, wide-range X-ray scattering information"
N2 - This dataset is a complete set of raw, processed and analyzed data, complete with Jupiter notebooks, associated with the manuscript mentioned in the title.
In the manuscript, we provide a "systems architecture"-like overview and detailed discussions of the methodological and instrumental components that, together, comprise the "MOUSE" project (Methodology Optimization for Ultrafine Structure Exploration). Through this project, we aim to provide a comprehensive methodology for obtaining the highest quality X-ray scattering information (at small and wide angles) from measurements on materials science samples.
KW - X-ray scattering
KW - Measurement methodology
KW - Traceability derivation
KW - Multi-scale measurements
KW - Systems architecture
KW - Nanomaterials
PY - 2020
DO - https://doi.org/10.5281/zenodo.4312953
PB - Zenodo
CY - Geneva
AN - OPUS4-51825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - The MOUSE project - A meticulous approach for obtaining traceable, wide-range X-ray scattering information
N2 - Herein, we provide a "systems architecture"-like overview and detailed discussions of the methodological and instrumental components that, together, comprise the "MOUSE" project (Methodology Optimization for UltrafineStructure Exploration). The MOUSE project provides scattering information on a wide variety of samples, with traceable dimensions for both the scattering vector (q) and the absolute scattering cross-section (I). The measurable scattering vector-range of 0.012≤ q (nm-1) ≤ 92, allows information across a hierarchy of structures with dimensions ranging from ca. 0.1 to 400 nm. In addition to details that comprise the MOUSE project, such as the organisation and traceable aspects, several representative examples are provided to demonstrate its flexibility. These include measurements on alumina membranes, the tobacco mosaic virus, and dual-source information that overcomes fluorescence limitations on ZIF-8 and iron-oxide-containing carbon catalyst materials.
KW - X-ray scattering
KW - MOUSE
KW - Instrumentation
KW - SAXS
KW - Methodology
KW - Traceability
KW - Wide-range
KW - Data curation
KW - FAIR
KW - Uncertainties
KW - Nanomaterials
KW - Nanometrology
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528669
DO - https://doi.org/10.1088/1748-0221/16/06/P06034
VL - 16
IS - 6
SP - 1
EP - 50
PB - IOP
CY - Bristol, UK
AN - OPUS4-52866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - X-ray Scattering for Nanostructure Quantification, and the Quest for the Perfect Experiment
N2 - Compared to the clear, real-space images you can get from electron microscopy, X-ray scattering patterns are rather featureless. These patterns, however, contain structural information from all of the material structure illuminated by the X-ray beam. With this technique, you can measure nanoparticle dispersions, catalysts, composites, MOF powders, battery materials, light metal alloys and gels to reveal information on the structural features found within these materials. We have even measured many such materials for several research groups from the University of Birmingham, revealing structure features in the sub-nm to the micrometer range.
Measuring an X-ray scattering pattern is relatively easy, but measuring a high-quality, useful pattern requires significant effort and good laboratory organization. Such laboratory organization can help address the reproducibility crisis in science, and easily multiply the scientific output of a laboratory, while greatly elevating the quality of the measurements. We have demonstrated this for small- and wide-angle X-ray scattering in the MOUSE project (Methodology Optimization for Ultrafine Structure Exploration) [1]. With the MOUSE, we have combined: a) a comprehensive and highly automated laboratory workflow with b) a heavily modified X-ray scattering instrument. This combination allows us to collect fully traceable scattering data, within a well-documented, FAIR-compliant data flow (akin to what is found at the more automated synchrotron beamlines). With two full-time researchers, our lab collects and interprets thousands of datasets, on hundreds of samples, for dozens of projects per year, supporting many users along the entire process from sample selection and preparation, to the analysis of the resulting data.
T2 - School of Chemistry Seminars
CY - Birmingham, UK
DA - 10.11.2021
KW - X-ray scattering
KW - MOUSE
KW - Instrumentation
KW - SAXS
KW - Methodology
KW - Nanostructure
PY - 2021
UR - https://www.youtube.com/watch?v=N2kY4wbqeM4
AN - OPUS4-53810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Rhode, Michael
T1 - Hydrogen embrittlement and mechanical properties of 9 % Cr P92 steel and P91 weld metal
N2 - Martensitic 9 %-Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen assisted cracking. The focus of this study was the microstructure and heat treatment effect on the mechanical properties of P92 base material and P91 multi-layer weld metal in both as-welded and post weld heat treated (PWHT) condition.
Tensile tests with hydrogen free reference samples and electrochemically hydrogen charged samples were carried out, the mechanical properties were assessed and supported by dedicated fractographic analysis. In addition, hydrogen and microstructure dependent fracture criteria were calculated. All investigated microstructures showed a hydrogen influenced degradation of the mechanical properties compared to the hydrogen free reference samples. In that connection, the as welded martensitic P91 weld metal had the highest degree of degradation in presence of hydrogen. The P91 PWHT weld metal and the P92 base material had comparable properties. From that point of view, a significantly increased risk for hydrogen assisted cold cracking during welding fabrication of P91 weld joints must be considered before any heat treatment is conducted.
T2 - IIW Annual Assembly, Meeting of Commission IX-C
CY - Tokyo, Japan
DA - 21.07.2022
KW - Creep-resistant steel
KW - Mechanical properties
KW - Hydrogen assisted cracking
KW - Weld joint
KW - Degradation
PY - 2022
AN - OPUS4-55462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Weldability of dissimilar metal welds of innovative high and medium entropy alloys to austenitic stainless steels joint by tungsten inert gas and friction stir welding
N2 - The new multi-element alloying concept of systems with defined entropy (HEA - High Entropy Alloy or MEA - Medium Entropy Alloy) is increasing in materials research interest. Improved properties or combinations of properties are shown by several systems. Thus, the resulting microstructures and production of HEA/MEA as well as properties have been primarily investigated so far. Furthermore, processing is a key issue to transfer HEA/MEA systems to real components. Since welding is the most important joining process for metals, it is crucial to investigate the influence of welding to guarantee component integrity. Since most HEA are made of expensive alloying elements such as Co or Ni, they will not be used entirely as structural materials. Thus, it can be advantageous to weld conventional alloys such as austenitic stainless steels with the HEA and MEA to produce components that are both application-oriented and economically viable. Therefore, in this paper, first results of dissimilar metal welding, by tungsten inert gas- (TIG) and friction stir welding (FSW), of a CoCrFeMnNi HEA as well as a CoCrNi MEA with a conventional AISI 304 austenitic stainless steel are presented. The focus is on the microstructure formation due to the two welding processes. The results of TIG welding show a dendritic microstructure, whereas in FSW both materials are stirred but still coexist.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - High Entropy Alloy
KW - Medium Entropy Alloys
KW - Welding microstructure
PY - 2022
AN - OPUS4-55442
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Towards component safety in laser powder bed fusion of metals
N2 - The thermal history during additive manufacturing of complex components differs significantly from the thermal history of geometrically primitive test specimens. This can result in differences in properties that can lead to different material behavior. In this talk, the concept of representative test specimens is introduced, which enables the transfer of thermal histories from complex geometries to simple geometries, which can lead to better comparability of material properties.
T2 - Additive Alliance
CY - Hamburg, Germany
DA - 05.03.2024
KW - Additive manufacturing
KW - Heat accumulation
KW - Laboratory specimens
KW - In situ monitoring
KW - Representative specimens
KW - Thermal history
PY - 2024
AN - OPUS4-60263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Rüden, H.
T1 - Röntgen-Computertomographie (CT) für die Kulturguterhaltung
N2 - Als bildgebendes und zerstörungsfreies Verfahren eignet sich die Röntgen-Computertomographie (CT) insbesondere bei der Untersuchung von Kunst- und Kulturgütern. Die für Werkstoffprüfung und Materialanalyse konzipierten CT-Anlagen bieten dank hoher Röntgenleistung die Möglichkeit zusätzlich zu Holz, Keramiken und Kunststoffen auch stark schwächende Materialien, wie bspw. Metalle, zu durchdringen. Für eine hohe räumliche Auflösung im unteren Mikrometerbereich (2-200µm) sorgen entsprechend ausgelegte CT-Anlagen. In der Bundesanstalt für Materialforschung und -prüfung (BAM) stehen mehrere solcher CT-Anlagen für unterschiedliche Fragestellungen sowie Probengrößen und - materialien zur Verfügung. Einige Beispiele aus den vergangenen Arbeiten der BAM veranschaulichen das große Potential dieser Untersuchungsmethode.
Da bei einer CT-Messung in der Regel das gesamte Untersuchungsobjekt erfasst und in ein digitales Volumenmodell überführt wird, eröffnet sich für Archäologen und Restoratoren die Möglichkeit Untersuchungen hinsichtlich Materialzusammensetzung, Erhaltungszustand und Herstellungstechnik am virtuellen Objekt vorzunehmen, ohne die Originalsubstanz zu beeinträchtigen. Gegenüber der klassischen Radiografie, bei der nur eine zweidimensionale Abbildung erreicht wird, bietet die CT-Untersuchung die Möglichkeit innenliegende Strukturen dreidimensional zu erfassen. Die notwendige Bestimmung der Objektoberfläche erlaubt zudem die Erstellung eines Oberflächenmodells des untersuchten Gegenstandes. Damit lassen sich unter anderem mechanische Simulationen (Belastung, Durchbiegung, Durchströmung) durchführen. Der erzeugte Datensatz kann somit auch zur Herstellung eines Replikats im 3D-Druckverfahren genutzt werden. Anhand der Untersuchung der Mandoline von Smorsone wird gezeigt, wie eine CT-Messung durchgeführt wird und wie in dem anschließend rekonstruierten 3D-Datensatz mittels Koordinatenmesstechnik Maße (Abstände, Wandstärken, Winkel) exakt ermittelt werden können.
T2 - Jahrestagung der Gesellschaft für Musikforschung
CY - Berlin, Germany
DA - 28.09.2022
KW - Mikro-CT
KW - Bildverarbeitung
KW - Holz
KW - Bronze
KW - ZfP
PY - 2022
AN - OPUS4-56412
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blasón Gonzalez, Sergio
A1 - Fernández-Canteli, A.
A1 - Poveda, E.
A1 - Ruiz, G.
A1 - Yu, R. C.
A1 - Castillo, E.
T1 - Damage evolution and probabilistic strain-lifetime assessment of plain and fiber-reinforced concrete under compressive fatigue loading: Dual and integral phenomenological model
N2 - A phenomenological approach is proposed to describe and predict the random behaviour of the total strain in plain and fiber concrete under compressive fatigue loading. Twofold viewpoints are considered in the assessment of the fatigue damage process. The first one, acknowledged as the stochastic cumulative damage evolution in terms of the number of applied cycles is represented by a sample function, physically identified with the total specimen strain caused by matrix microcracking. The second one is ascribed to the intrinsic scatter of the total lifetime referred to as the prefixed ultimate fatigue strain limit state (not necessarily failure). The sample function, once normalized to the total fatigue lifetime, is identified as a cumulative distribution function (cdf) of the generalized extreme value (GEV) family, particularly as Weibull distribution. Besides the reliable probabilistic lifetime prediction for the material under compressive fatigue, the approach allows fatigue tests to be prematurely interrupted while the remaining evolution of the ε-N curve up to failure is fully restored from the fragment recorded. In this way, a remarkable time and cost reduction of the experimental program is achieved without detriment of data reliability.
KW - Prematurely interrupted tests
KW - Fatigue damage
KW - Cyclic creep curve
KW - Lifetime normalization
KW - Probabilistic lifetime prediction
PY - 2022
DO - https://doi.org/10.1016/j.ijfatigue.2022.106739
SN - 0142-1123
VL - 158
SP - 1
EP - 20
PB - Elsevier Ltd.
AN - OPUS4-55239
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
A1 - Przyklenk, A.
T1 - European Metrology Network for Advanced Manufacturing
N2 - The progress of Advanced Manufacturing, which has been identified by the European Commission as a Key Enabling Technology (KET) for future economic and societal progress is strongly reliant on the development of metrology capabilities. EURAMET, the association of metrology institutes in Europe, has established metrology research programs to address the metrology requirements across a spectrum of different thematic areas. In order to leverage the benefits of these developments on the wider industrial landscape, a high-level coordination of the metrology community supporting the Advanced Manufacturing landscape is required. This coordination is aimed to be achieved by the establishment of European Metrology Networks (EMNs), which are intended by EURAMET to provide a sustainable structure for stakeholder engagement and support. The joint networking project 19NET01 AdvManuNet funded by EMPIR for 4 years, started in June 2020 and aims to accelerate the process of establishing an EMN to strengthen Europe’s position in Advanced Manufacturing. The AdvManuNet project aims to support the establishment of an EMN on Advanced Manufacturing via the following specific aims:
1. Creation of a single hub for stakeholder engagement across the landscape of various industrial sectors including relevant societies and standardization bodies.
2. Development of a Strategic Research Agenda (SRA) and roadmaps for Advanced Manufacturing metrology based on the stakeholder engagement activities, considering current gaps in metrological capabilities existing networks and roadmaps.
3. Establish a knowledge-sharing program for Advanced Manufacturing stakeholders, promoting the dissemination and exploitation of the results of the project, including those from previous EU funded research projects.
4. Development of a sustainable web-based platform and service desk for Advanced Manufacturing stakeholders to allow for easy access to European metrology capabilities and support the wider advanced manufacturing community with metrology-based requirements.
5. Develop a plan for a coordinated and sustainable European metrology infrastructure for Advanced Manufacturing via a European Metrology Network.
The project concept followed by the scope and definition of Advanced Manufacturing will be described. The analysis of the current capability of metrology for Advanced Manufacturing and the preliminary concepts for the strategic research agenda will be presented with a focus on dimensional metrology.
T2 - CIM 2021
CY - Online meeting
DA - 07.09.2021
KW - Advanced manufacturing
KW - Metrology
KW - European Metrology Networks (EMNs)
KW - Strategic Research Agenda (SRA)
KW - Stakeholder
PY - 2021
AN - OPUS4-54101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ebell, Gino
A1 - Burkert, Andreas
T1 - Standortabhängige Dauerhaftigkeitsbetrachtungen von Zink unter atmosphärischer Korrosion
N2 - In maritimer Exposition können Zinkbauteile Nutzungsdauern von 50 Jahren erreichen. Dabei werden Expositionen mit Spritzwasserbelastung durch Meerwasser nicht betrachtet. Normative Betrachtungen und Korrosionsprognosen basierend auf Einjahreswerten liefern hier grundlegend falsche Ergebnisse, da sie eine signifikant höhere Belastung der Atmosphäre mit SO2 voraussetzen.
T2 - AK-Sitzung Atmosphärische Korrosion
CY - Berlin, Germany
DA - 24.10.2023
KW - Korrosion
KW - Deckschichtbildung
KW - Zink
PY - 2023
AN - OPUS4-59342
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Innovative Multielement-Legierungen: Aktuelle Ergebnisse zur Schweißbarkeit und Anwendungseigenschaften
N2 - Multielement-Legierungen (MPEA – multiple pricipal element alloys) stellen eine neue Klasse von Werkstoffen dar, die aus mindestens drei äquiatomaren Legierungselementen mit jeweils einem Gehalt von 5–35 Atom-% bestehen. Somit unterscheidet sich das Legierungskonzept fundamental von konventionellen bspw. Stahl- oder Al-basierten Legierungen. In jüngster Zeit lag der Schwerpunkt auf dem Legierungs-Design der MPEA und der Überprüfung bzw. Erreichung der gewünschten Eigenschaften bzw. -kombinationen. Hierzu werden die Legierungselemente gezielt ausgewählt und die Mikrostrukturen ein- und zum Teil auch mehrphasig eingestellt. Ziel sind hochinnovative MPEA mit angepassten Eigenschaften für die industrielle Anwendung. Dabei sollen insbesondere die bei konventionellen Legierungen wesentlichen Zielkonflikte, wie bspw. der Trade-off zwischen Festigkeit und Duktilität, überwunden werden. Darüber hinaus sind mechanische Eigenschaften bei sehr hohen sowie kryogenen Temperaturen bei gleichzeitig höchster Korrosionsbeständigkeit von hohem Interesse. Die Herstellung von Bauteilen erfordert dazu werkstoff- und beanspruchungsgerechte Füge- bzw. Schweißverfahren. Der Schweißeignung von MPEA wurde bis Ende 2021 nur äußert wenig Aufmerksamkeit zuteil. Die Auswirkungen durch Schweißprozesse auf die Metallurgie und die gewünschten Eigenschaften sind bisher kaum bekannt und limitieren die potenzielle Anwendbarkeit als Funktions- oder Konstruktionswerkstoffe.
In einem interdisziplinären BAM-Forschungsprojekt werden aktuell grundlegende Untersuchungen zur Schweißverarbeitung und resultierender Mikrostruktur-Anwendungseigenschafts-Beziehung verschiedener MPEA durchgeführt. Insbesondere Wärmeeinflusszone und Schweißgut sind geprägt durch eine Mikrostruktur, die aus Ungleichgewichtszuständen resultiert. Im Falle von MPEA wurde dies bisher nicht systematisch untersucht. Dazu erfolgte im Rahmen des Projektes eine umfassende Literaturauswertung zum Schweißen von MPEA und Zusammenfassung in einer umfassenden, systematischen Datenbasis. Aus diesem Grund sollen in der vorliegenden Studie die bisher bedeutsamsten Erkenntnisse zur Schweißbarkeit von MPEA systematisch nach MPEA-Typ und Schweißverfahren geordnet und mit eigenen aktuellen Forschungsergebnissen verglichen werden. Durch WIG- und Rührreibschweißversuche an den MPEA-Systemen CoCrNiFeMn bzw. CoCrNi konnten im Projektverlauf bereits wesentliche Fragestellungen beantwortet werden. Dazu zählen Auftreten bzw. Verhinderung intermetallischer Phasen/Seigerungen oder deren Auswirkung auf die Eigenschaften der Schweißverbindung (bspw. Festigkeit oder Korrosionsbeständigkeit).
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Magdeburg, Germany
DA - 14.12.2022
KW - High Entropy Alloy
KW - Schweißen
KW - Multielementlegierungen
PY - 2022
AN - OPUS4-56701
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Do Microbes like Additively Manufactured Aluminium? First Details of a Corrosion Test using Sulphate-Reducing Bacteria
N2 - Additively manufactured metals become relevant for industrial application. Although many studies on wet corrosion of these metals have been conducted, to the authors knowledge no study seems to contain microbiological corrosion (MIC). In the presented study an experiment was conducted on PBF-LB/AlSi10Mg to test this material's susceptibility for MIC. The tested specimen were analysed using Computed Tomography before and after the MIC experiment to enable a detailed characterisation the damage on the specimens' global and local level. A global reduction of material was observed. In addition, localised damage along process inherent features of the materials microstructure was observed.
T2 - Beiratssitzung TF Umwelt
CY - Berlin, Germany
DA - 17.03.2025
KW - Computed Tomography
KW - Additive Manufacturing
KW - Biocorrosion
KW - Sulphate-reducing Bacteria
KW - Microbially influenced corrosion
PY - 2025
AN - OPUS4-62772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Rührreibschweißen von Hoch- und Mediumentropie-Legierungen
N2 - Hoch- und Mittelentropie-Legierungen (engl. High/Medium Entropy Alloys–HEA/MEA) sind relativ neue Werkstoffklassen. Im Gegensatz zu herkömmlichen Legierungen bestehen HEA aus fünf bzw. MEA aus drei oder vier Legierungselementen im äquiatomaren Gleichgewicht. Viele HEA weisen aufgrund hervorragender struktureller Eigenschaftskombinationen von sehr tiefen bis zu hohen Temperaturen enormes Anwendungspotential auf. Die Anwendung für reale Bauteile stellt jedoch die zentrale Frage der Eignung für die fügetechnische Verarbeitung. Dieser Aspekt findet in der weltweiten Materialforschung bisher kaum Beachtung. Anforderungen an die zuverlässige und sichere fügetechnische Verarbeitung dieser Werkstoffe sind von wesentlicher Bedeutung hinsichtlich wirtschaftlicher Bauteilfertigung für spätere potenzielle Anwendungsbereiche, bspw. in der Energietechnik. Das Rührreibschweißen (engl. Friction Stir Welding–FSW) stellt hierbei einen vielversprechenden Fügeprozess dar, dessen Hauptvorteil in der Schweißprozesstemperatur unterhalb der Schmelztemperatur der zu fügenden Werkstoffe liegt. Dies bedingt die Vermeidung der Ausbildung von harten, versprödenden intermetallischen Phasen, wie sie z. B. beim konventionellen Schmelzschweißen von Eisen-Aluminium-Verbindungen auftreten. Die vorliegende Arbeit stellt grundlegende Untersuchungen zur Schweißbarkeit einer CoCrFeMnNi-Legierung (HEA) und einer CoCrNi-Legierung (MEA) mit dem FSW-Prozess vor. Die Versuchsschweißungen werden mittels mikroskopischer Analysen hinsichtlich des Schweißnahtaufbaus sowie Schweißnahtfehlern charakte-risiert. FSW zeigt sich als grundlegend geeignet zur Verbindungsschweißung der HEA bzw. MEA. Anhand dieser Ergebnisse kann eine weitere Bewertung der Schweißbarkeit erfolgen.
T2 - 4 Niedersächsisches Symposium Materialtechnik Clausthal
CY - Online meeting
DA - 25.02.2021
KW - Hochentropie Legierung
KW - Rührreibschweißen
KW - Mediumentropie Legierung
PY - 2021
AN - OPUS4-52257
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - García-González, M.
A1 - Blasón Gonzalez, Sergio
A1 - García-García, I.
A1 - Lamela-Rey, M. J.
A1 - Fernández-Canteli, A.
A1 - Álvarez-Arenal, Á.
T1 - Optimized planning and evaluation of dental implant fatigue testing: A specific software application
N2 - Mechanical complications in implant-supported fixed dental prostheses are often related to implant and prosthetic design. Although the current ISO 14801 provides a framework for the evaluation of dental implant mechanical reliability, strict adherence to it may be difficult to achieve due to the large number of test specimens which it requires as well as the fact that it does not offer any probabilistic reference for determining the endurance limit. In order to address these issues, a new software program called ProFatigue is presented as a potentially powerful tool to optimize fatigue testing of implant-supported prostheses. The present work provides a brief description of some concepts such as load, fatigue and stress-number of cycles to failure curves (S-N curves), before subsequently describing the current regulatory situation. After analyzing the two most recent versions of the ISO recommendation (from 2008 and 2016), some limitations inherent to the experimental methods which they propose are highlighted. Finally, the main advantages and instructions for the correct implementation of the ProFatigue free software are given. This software will contribute to improving the performance of fatigue testing in a more accurate and optimized way, helping researchers to gain a better understanding of the behavior of dental implants in this type of mechanical test.
KW - Dental materials
KW - Prostheses
KW - Implants
KW - Reference standards
KW - Software
KW - Cyclic loading
KW - Fatigue
KW - Lifetime
KW - S-N curve
KW - Staircase method
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516268
DO - https://doi.org/10.3390/biology9110372
SN - 2079-7737
VL - 9
IS - 11
SP - 372-1
EP - 372-12
PB - MDPI
CY - Basel
AN - OPUS4-51626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monavari, M.
A1 - Medhekar, R.
A1 - Nawaz, Q.
A1 - Monavari, Mehran
A1 - Fuentes‐Chandía, M.
A1 - Homaeigohar, S.
A1 - Boccaccini, A. R.
T1 - A 3D printed bone tissue engineering scaffold composed of alginate dialdehyde-gelatine reinforced by lysozyme loaded cerium doped mesoporous silica-calcia nanoparticles
N2 - A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) is 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raise the mechanical stiffness of the hydrogel composite scaffold and induce surface apatite mineralization, when the scaffold is immersed in simulated body fluid (SBF). Moreover, the scaffolds can co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds can hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel bone tissue engineering (BTE) scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth.
KW - Materials chemistry
KW - Polymers and plastics
KW - Biomaterials
KW - Bioengineering
KW - Biotechnology
KW - 3D printing
KW - Bone tissue engineering
KW - Drug delivery
KW - Lysozyme
KW - Mesoporous SiO2-CaO nanoparticles
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581238
DO - https://doi.org/10.1002/mabi.202200113
SN - 1616-5195
VL - 22
IS - 9
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-58123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernádez-Canteli, A.
A1 - Castillo, E.
A1 - Blasón Gonzalez, Sergio
T1 - A methodology for phenomenological analysis of cumulative damage processes. Application to fatigue and fracture phenomena
N2 - Sample functions, i.e., stochastic process realizations, are used to define cumulative damage phenomena which end into an observable terminal state or failure. The complexity inherent to such phenomena justifies the use of phenomenological models associated with the evolution of a physical magnitude feasible to be monitored during the test. Sample functions representing the damage evolution may be identified, once normalized to the interval [0,1], with cumulative distribution functions (cdfs), generally, of the generalized extreme value (GEV) family. Though usually only a fraction of the whole damage evolution, according to the specific problem handled, is available from the test record, the phenomenological models proposed allow the whole damage process to be recovered. In this way, down- and upwards extrapolations of the whole damage process beyond the scope of the experimental program are provided as a fundamental tool for failure prediction in the practical design. The proposed methodology is detailed and its utility and generality confirmed by its successive application to representative well-known problems in fatigue and fracture characterization. The excellent fittings, the physical interpretation of the model parameters and the good expectations to achieve a complete probabilistic analysis of these phenomena justify the interest of the proposed phenomenological approach with possible applications to other cumulative damage processes.
KW - Bayesian technique
KW - Sample random results
KW - Stochastic sample functions
KW - Probabilistic assessment
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552371
DO - https://doi.org/10.1016/j.ijfatigue.2021.106311
SN - 0142-1123
VL - 150
SP - 106311
PB - Elsevier Ltd.
AN - OPUS4-55237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nourinejhad Zarghani, Shaheen
A1 - Ehlers, Jens
A1 - Monavari, Mehran
A1 - von Bargen, Susanne
A1 - Hamacher, Joachim
A1 - Büttner, Carmen
A1 - Bandte, Martina
T1 - Applicability of Different Methods for Quantifying Virucidal Efficacy Using MENNO Florades and Tomato Brown Rugose Fruit Virus as an Example
N2 - After entry of a quarantine/regulated pathogen, infected plants shall be destroyed, and the cultivated area (e.g., greenhouse) shall be disinfected. Therefore, the selection of an effective disinfectant plays an important role. With the availability of different methods for virus quantification, we investigated the application of quantitative ELISA (qELISA), RT-qPCR (reverse transcription-quantitative polymerase chain reaction), and bioassays for the quantification of disinfectant efficacy. Therefore, we estimated the titer reduction in tomato brown rugose fruit virus (ToBRFV), a regulated pathogen, in plant sap and on germ carriers after treatment with MENNO Florades 4% for 16 h. The virus load before and after the treatment was measured with the mentioned methods. The RT-qPCR and qELISA methods showed very low efficacy in the presence of the disinfectant. Although bioassays are time-consuming, need purified particles for establishing the quantification models, and are less sensitive than RT-qPCR, they were able to quantify the differences in virus titer in the presence/absence of disinfectant. Interestingly, the bioassays reached at least the lower limit sensitivity of a qELISA. By being less sensitive to the presence of the disinfectant, bioassays proved to be the only technique for the determination of the disinfectant efficacy against ToBRFV on different germ carriers as well as on virus-infected plant sap.
KW - Plant Science
KW - Ecology
KW - Evolution
KW - Behavior and Systematics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585497
DO - https://doi.org/10.3390/plants12040894
VL - 12
IS - 4
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-58549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nourinejhad Zarghani, Shaheen
A1 - Monavari, Mehran
A1 - Ehlers, Jens
A1 - Hamacher, Joachim
A1 - Büttner, Carmen
A1 - Bandte, Martina
T1 - Comparison of Models for Quantification of Tomato Brown Rugose Fruit Virus Based on a Bioassay Using a Local Lesion Host
N2 - Considering the availability of serological and molecular biological methods, the bioassay has been paled into insignificance, although it is the only experimental method that can be used to demonstrate the infectivity of a virus. We compared goodness-of-fit and predictability power of five models for the quantification of tomato brown rugose fruit virus (ToBRFV) based on local lesion assays: the Kleczkowski model, Furumoto and Mickey models I and II, the Gokhale and Bald model (growth curve model), and the modified Poisson model. For this purpose, mechanical inoculations onto Nicotiana tabacum L. cv. Xanthi nc and N. glutionosa L. with defined virus concentrations were first performed with half-leaf randomization in a Latin square design. Subsequently, models were implemented using Python software and fitted to the number of local lesions. All models could fit to the data for quantifying ToBRFV based on local lesions, among which the modified Poisson model had the best prediction of virus concentration in spike samples based on local lesions, although data of individual indicator plants showed variations. More accurate modeling was obtained from the test plant N. glutinosa than from N. tabacum cv. Xanthi nc. The position of the half-leaves on the test plants had no significant effect on the number of local lesions.
KW - Plant Science
KW - Ecology
KW - Evolution
KW - Behavior and Systematics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585506
DO - https://doi.org/10.3390/plants11243443
VL - 11
IS - 24
SP - 1
EP - 16
PB - MDPI
AN - OPUS4-58550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaudry, Mohsin Ali
T1 - Simulation of heat accumulation during laser powder bed fusion of 316L stainless steel
N2 - In this talk, a numerical study of the heat accumulation during LPBF based manufacturing of 316L steel parts is presented. For the simulation, a computationally efficient FEM model is used, where several layers are simultaneously exposed to a volumetric heat source. For the validation of the model, the temperature field from simulation is compared with emissivity-corrected temperature measurements, which are obtained using thermography during experiments.
T2 - ACEX 2022
CY - Florence, Italy
DA - 05.07.2022
KW - FEM
KW - LPBF
KW - Inter layer time
PY - 2022
AN - OPUS4-55523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - O'Connor, Daniel
T1 - European Metrology Network (EMN) for Advanced Manufacturing Development of the Strategic Research Agenda (SRA)
N2 - The European Commission has identified Advanced Manufacturing and Advanced Materials as two of six Key Enabling Technologies (KETs). It is considered that Metrology is a key enabler for the advancement of these KETs. Consequently, EURAMET, the association of metrology institutes in Europe, has strengthened the role of Metrology for these KETs by enabling the creation of a European Metrology Network (EMN) for Advanced Manufacturing. The EMN is comprised of National Metrology Institutes (NMIs) and Designated Institutes (DIs) from across Europe and was formally established in October 2021. The aim of the EMN is to provide a high-level coordination of European metrology activities for the Advanced Manufacturing community.
The EMN itself is organized in three sections representing the major stages of the manufacturing chain: 1) Advanced Materials, 2) Smart Manufacturing Systems, and 3) Manufactured Components & Products. The EMN for Advanced Manufacturing is engaging with stakeholders in the field of Advanced Manufacturing (large companies & SMEs, industry organisations, existing networks, and academia), as well as the wider Metrology community, including Technical Committees, to provide input for the Strategic Research Agenda (SRA) on Metrology for Advanced Manufacturing.
This contribution will give an overview about the first version of the SRA prepared by the EMN for Advanced Manufacturing.
T2 - Euspen, 23rd International Conference & Exhibitio
CY - Copenhagen, Danmark
DA - 13.06.2023
KW - European Metrology Network (EMN)
KW - Advanced Manufacturing
KW - Metrology
KW - Strategic Research Agenda (SRA)
PY - 2023
AN - OPUS4-59176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
T1 - Precise Position Detection for Repair of Gas Turbine Blades using PBF-LB/M
N2 - Additive manufacturing (AM) technologies are becoming increasingly important, not only for the manufacture of parts, but also as repair technology that complement existing production technologies. Powder bed fusion of metals by laser beam (PBF-LB/M) combines the freedom in design with high achievable accuracy, making it ideal as a repair approach. However, there are still challenges in adapting process for repair applications. When mounting parts inside PBF-LB/M machines, their real position within the build volume is unknown. One goal of a repair process is to minimize the offset between the base component and the additively manufactured structure to reduce additional rework. For a minimum offset between component and additively manufactured structure, the actual position of the component has to be identified with high precision within the machine coordinate system (MCS). In this work a process setup is presented that allows the actual position of a gas turbine blade to be detected inside a PBF-LB/M machine. A high resolution camera with 65 megapixel is used for this purpose. The presented setup is implemented on a SLM 280 HL PBF-LB/M machine. In addition to the setup, a novel repair workflow using PBF-LB/M is presented. The developed setup and workflow consider inaccuracies in the component and camera mounting, as well as process inaccuracies. This includes keystone distortion correction by homography. The machine setup and workflow are used to repair a real gas turbine blade. Subsequently the offset between the turbine blade and the additivley manufactured structure is validated by 3D scanning the repaired part. The maximum offset is 160 µm. The presented approach can be extended to other geometries and PBF-LB/M machine manufacturers. The high-resolution camera approach is platform independent, which facilates the market penetration of PBF-LB/M repair processes.
T2 - International Symposium Additive Manufacturing 2023 (ISAM 2023)
CY - Dresden, Germany
DA - 30.11.2023
KW - additive manufacturing
KW - powder bed fusion of metals utilizing a laser beam
KW - PBF-LB/M
KW - hybrid repair
KW - position detection
KW - high-resolution camera
PY - 2023
AN - OPUS4-59193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
A1 - Poka, Konstantin
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
A1 - Polte, Julian
T1 - Advanced camera calibration for lens distortion correction in hybrid manufacturing processes: An exemplary application in laser powder bed fusion (PBF-LB/M)
N2 - Hybrid additive manufacturing is becoming increasingly important in the field of additive manufacturing. Hybrid approaches combine at least two different manufacturing processes. The focus of this work is the build-up of geometries onto conventionally manufactured parts using Powder Bed Fusion with Laser Beam of Metals (PBF-LB/M). The hybrid build-up requires a precise position detection system inside the PBF-LB/M machines to determine the exact position of the existing component. For this purpose, high-resolution camera systems can be utilized. However, the use of a camera system is associated with several challenges. The captured images are subject to various distortions of the optical path. Due to these distortions, it is not possible to use the images for measurements and, therefore, it is not possible to calculate the positions of objects. In this study a homography matrix is calculated to correct keystone distortion in the images. Different calibration patterns have been tested for the calculation of the homography matrix. The influence of the number of calibration points on the precision of position detection of objects is determined. Furthermore, the influence of an additional camera calibration by using ChArUco boards is evaluated. The result is a camera calibration workflow with associated calibration pattern for a precise position detection of parts inside PBF-LB/M machines allowing a hybrid build-up with minimum physical offset between base component and build-up.
T2 - euspen’s 24th International Conference & Exhibition
CY - Dublin, Ireland
DA - 10.06.2024
KW - Additive manufacturing
KW - Hybrid build-up
KW - Position detection
KW - Camera calibration
PY - 2024
SP - 1
EP - 4
AN - OPUS4-60599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krösche, C.
A1 - Malow, Marcus
A1 - Budde, K.
T1 - False-Positive Results of UN Test O.2 Liquid Oxidizer Test of Polychlorosilanes
N2 - According to UN Test O.2, surprisingly, the polychlorosilanes hexachlorodisilane (HCDS), octachlorotrisilane (OCTS) and decachlorotetrasilane (DCTS) formally fulfill the criteria of the “test for oxidizing liquids”. This result is in contrast to the properties of polychlorosilanes that are described in the literature and those we have experienced in our own production.
By investigating the reaction products from the UN O.2 test reactor, using IR, Raman and XPS spectroscopy, it was shown that the results are not due to oxidizing properties of HCDS, OCTS or DCTS, but are caused by the specified test substance cellulose. To our knowledge, this is the very first substance class in which the reference substance oxidizes the test sample, instead of vice versa. This represents an important limitation of the internationally used UN Test O.2 for this substance class. The cause for this false-positive result is the known high degree of affinity of oxygen to silicon.
It is shown that the correctly executed UN Test O.2 produces false-positive results and that the polychlorosilanes do not have an oxidizing effect and, therefore, do not have to be classified as “oxidizing substances”.
KW - Polychlorosilanes
KW - UN Test O.2
KW - Hexachlorodisilane
KW - Octachlortrisilane
KW - Decachlorotetrasilane
KW - False-positive results
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523989
DO - https://doi.org/10.1016/j.jlp.2021.104434
VL - 70
SP - 104434
PB - Elsevier Ltd.
AN - OPUS4-52398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lüth, Peter
A1 - Uhlig, S.
A1 - Frost, K.
A1 - Malow, Marcus
A1 - Michael-Schulz, Heike
A1 - Schmidt, Martin
A1 - Zakel, Sabine
T1 - CEQAT-DGHS interlaboratory tests for chemical safety: Validation of laboratory test methods by determining the measurement uncertainty and probability of incorrect classification including so-called “Shark profiles”
N2 - Laboratory test results are of vital importance for correctly classifying and labelling chemicals as “hazardous” as defined in the UN Globally Harmonized System (GHS) / EC CLP Regulation or as “dangerous goods” as defined in the UN Recommendations on the Transport of Dangerous Goods. Interlaboratory tests play a decisive role in assessing the reliability of laboratory test results. Interlaboratory tests performed over the last 10 years have examined different laboratory test methods. After analysing the results of these interlaboratory tests, the following conclusions can be drawn:
1. There is a need for improvement and validation for all laboratory test methods examined.
2. To avoid any discrepancy concerning the classification and labelling of chemicals, the use of validated laboratory test methods should be state of the art, with the results accompanied by the measurement uncertainty and (if applicable) the probability of incorrect classification.
This paper addresses the probability of correct/incorrect classification (for example, as dangerous goods) on the basis of the measurement deviation obtained from interlaboratory tests performed by the Centre for quality assurance for testing of dangerous goods and hazardous substances (CEQAT-DGHS) to validate laboratory test methods. This paper outlines typical results (e.g. so-called “Shark profiles” – the probability of incorrect classification as a function of the true value estimated from interlaboratory test data) as well as general conclusions and steps to be taken to guarantee that laboratory test results are fit for purpose and of high quality.
T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE 2020)
CY - Brunswick, Germany
DA - 27.07.2020
KW - Dangerous goods
KW - Hazardous substances
KW - Interlaboratory test
KW - Test method
KW - Validation
KW - Quality assurance
KW - Measurement uncertainty
KW - Incorrect classification
KW - Shark profiles
PY - 2021
DO - https://doi.org/10.1016/j.jlp.2021.104532
SN - 0950-4230/
VL - 72
SP - 104532
PB - Elsevier Ltd.
AN - OPUS4-52751
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lüth, Peter
A1 - Malow, Marcus
T1 - CEQAT-DGHS Interlaboratory tests for chemical safety – A new gravimetric procedure for the gas flow measurement for flammable and toxic gases
N2 - Testing of hazardous materials and evaluating their hazardous properties concerning transport, handling or use is essential for the prevention of incidents. For this purpose, test methods have been developed and published that are used worldwide today (European Union, 2008, United Nations, 2019). For the evaluation of test results their correct measurement is of importance. On basis of the interlaboratory tests carried out by BAM and PTB within the framework of the CEQAT-DGHS in the last years, it is shown that there is a need for improvement in all the test methods examined so far. In addition to the interlaboratory tests further quality measures are mandatory (ISO, 2017). For example, methods for verifying the test equipment used in the laboratories should be developed.
The development of a verification method is demonstrated using the test method UN Test N.5 as an example. This test method is used to evaluate substances which in contact with water emit flammable gases. The basic principle of the verification method is demonstrated by Lüth et al. (2019). Requirements and difficulties during this development are discussed.
This test procedure UN Test N.5 has now been modified at BAM so that it is possible to measure very small or large amounts of both flammable and/or toxic gases over a long period of time in a validated and verified test apparatus, utilizing the principle of a gas collector. This allows us to determine slow as well as fast gas evolution rates. The determination of the evolution rates (e.g. total gas amount or flow rate) of toxic gases is of special interest because of the ongoing discussion how to evaluate and quantify toxic gases which are formed from a substance due to contact with water. Up today no validated test procedure for the measurement of evolution rates for toxic gases is described. It is shown that the newly modified test method could help to solve this problem.
T2 - 13th International Symposium on Hazards, Prevention, and Mitigation of Industrial Explosions
CY - Online meeting
DA - 27.07.2020
KW - Hazardous materials
KW - Transport regulations
KW - Flammable gases
KW - Toxic gases
PY - 2020
SP - Paper 1002
AN - OPUS4-51271
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Michael-Schulz, Heike
T1 - Classification of organic peroxide and self-reactive
N2 - Organic peroxide and self-reactive are classified into seven types according to their hazards. In order to determine the substance type, it is necessary to determine the properties based on test methods. The types range from type A, which is not accepted for transport in the packing in which it is tested, to type G, which is exempted from the provisions for organic peroxides or self-reactive substances.
T2 - Training course of the European Chemicals Agency (ECHA)
CY - Online meeting
DA - 17.03.2021
KW - Organische Peroxide
KW - Selbstzersetzliche Stoffe
KW - Peressigsäuren
KW - Self reactive substances
KW - Organic peroxides
KW - Peroxyacetic acids
PY - 2021
AN - OPUS4-53177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Scheuschner, Nils
A1 - Chand, Keerthana
A1 - Altenburg, Simon
T1 - Local porosity prediction in metal powder bed fusion using in-situ thermography: A comparative study of machine learning techniques
N2 - The formation of flaws such as internal porosity in parts produced by Metal-based Powder Bed Fusion with Laser Beam (PBF-LB/M) significantly hinders its broader industrial application, as porosity can potentially lead to part failure. Addressing this issue, this study explores the efficacy of in-situ thermography, particularly short-wave infrared thermography, for detecting and predicting porosity during manufacturing. This technique is capable of monitoring the part’s thermal history which is closely connected to the flaw formation process. Recent advancements in Machine Learning (ML) have been increasingly leveraged for porosity prediction in PBF-LB/M. However, previous research primarily focused on global rather than localized porosity prediction which simplified the complex prediction task. Thereby, the opportunity to correlate the predicted flaw position with expected part strain to judge the severity of the flaw for part performance is neglected. This study aims to bridge this gap by studying the potential of SWIR thermography for predicting local porosity levels using regression models. The models are trained on data from two identical HAYNES®282® specimens. We compare the effectiveness of feature-based and raw data-based models in predicting different porosity types and examine the importance of input data in porosity prediction. We show that models trained on SWIR thermogram data can identify systematic trends in local flaw formation. This is demonstrated for forced flaw formation using process parameter shifts and, moreover, for randomly formed flaws in the specimen bulk. Furthermore, we identify features of high importance for the prediction of lack-of-fusion and keyhole porosity from SWIR monitoring data.
KW - PBF-LB/M
KW - In situ monitoring
KW - Thermography
KW - Additive Manufacturing
KW - Process monitoring
KW - Porosity prediction
KW - Machine Learning
KW - Feature extraction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621798
DO - https://doi.org/10.1016/j.addma.2024.104502
SN - 2214-7810
VL - 95
SP - 1
EP - 17
PB - Elsevier B.V.
AN - OPUS4-62179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Einfluss von Wärmeführung und Bauteildesign auf die Eigenschaften und fertigungsbedingten Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle
N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein.
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Kaltrisssicherheit
KW - Wärmeführung
KW - Windenergie
PY - 2022
SN - 978-3-96144-189-1
VL - 382
SP - 737
EP - 745
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-56719
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Combined effect of heating rate and restraint condition on stress relief cracking susceptibility during PWHT of thick walled Cr Mo V steel submerged arc welded joints
N2 - Contemporary steels creep-resistant steels like the 13CrMoV9-10 are used as thick plates e.g., for applications in hydrocrackers. The large plate thickness requires high efficiency welding processes like submerged arc welding (SAW) and a mandatory post weld heat treatment (PWHT). The PWHT-parameters stem from a combination of empirical knowledge and traditional experiments on free shrinking (FS) welds. In that connection, the formation of so-called stress-relief cracking (SRC) must be anticipated. The SRC susceptibility of a welded component is a complex combination and interaction of com-ponent specific, thermal, and metallurgical factors. Many of which have to date not been conclusively researched. For example, it is well known that SRCs develop during PWHT due to formation and growth of carbides on prior austenite grain boundaries, resulting in a significant hardness increase (secondary hardening) and toughness decrease. This leads to a high SRC susceptibility of the coarse grain heat-affected zone (CGHAZ) of the last weld bead during PWHT. This is intensified in case of high residual stresses from the component-specific, structurally induced stiffness. In combination with multi-layer welding this leads to a multiaxial stress distribution. Nonetheless, the combined effect of PWHT and high-residual stresses on the SRC formation is merely unknown. For that reason, this study presents the effect of different heating rates in conjunction with a certain component stiffness. For that reason, SAW joints of 13CrMoV9-10 steel were investigated under FS and defined external restraint condition.
T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission II-A
CY - Ixia, Rhodes, Greece
DA - 07.07.2024
KW - Stress relief cracking
KW - Submerged arc welding
KW - Post weld heat treatment
KW - Cr-Mo-V steel
PY - 2024
AN - OPUS4-60675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Projektkurzvorstellung: Bewertung konstruktiv bedingter Erstarrungsrisse beim Schweißen hochfester Feinkornbaustähle
N2 - Die Integrität von Leichtbaustrukturen aus hochfesten Stählen ist zunehmend durch die Bildung von Heißrissen gefährdet. Aktuell treten Erstarrungsrisse an Konstruktionsmerkmalen auf, obwohl heißrisssichere niedriglegierte Grund- und Zusatzwerkstoffe als auch Schweißprozessbedingungen eingesetzt wurden. Werkstoff- und prozessseitig wurden diese Rissursachen bereits eingehend erforscht. Untersuchungen zum Aspekt der konstruktiv bedingten Heißrissvermeidung, aus denen sich Empfehlungen für ein beanspruchungsgerechtes Gestalten für KMU ableiten lassen, liegen bislang lückenhaft vor bzw. sind veraltet und für hochfeste Leichtbauten kaum zielführend. Konstruktive Gegenmaßnahmen zur Vermeidung von Erstarrungsrissen liegen oft nicht vor. Das Design und die konstruktiven Randbedingungen beeinflussen die Erstarrungsrisse entscheidend. Um eine schnelle Umsetzbarkeit der Resultate für KMU zu ermöglichen, soll eine einfache und kostengünstige Methodik zur Heißrissbewertung entwickelt werden. Gerade KMU haben einen hohen Nachholbedarf an heißrisssicheren und wirtschaftlichen Leichtbaulösungen. Konstrukteure und Anwender aus KMU würden durch fundierte Kenntnisse über mögliche erstarrungsrisskritische Beanspruchungszustände kostenintensive Qualitätsmängel vermeiden. Das Ziel ist es, Kenngrößen zu identifizieren, die während des Schweißens unter realitätsnahen Bedingungen erfasst werden können. Diese Parameter werden als Transfergrößen genutzt, um eine Heißrissbewertung eines geschweißten Bauteils zu ermöglichen. Anliegen des Vorhabens wird die Prüfung und Bewertung von typischen Beanspruchungszuständen beim Schweißen von Leichtbaustrukturen hinsichtlich ihrer Erstarrungsrissneigung sein. Durch Ableitung klassifizierter Gestaltungshinweise wird ein signifikanter Beitrag zur Steigerung der Wettbewerbsfähigkeit insbesondere für KMU geliefert. Die Ergebnisse werden in Normen zur sicheren schweißtechnischen Fertigung von Leichtbaustrukturen aus hochfesten Stählen direkt einfließen.
T2 - Sitzung des NA 092-00-05 GA "Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)"
CY - Online meeting
DA - 10.03.2022
KW - Schweißen
KW - Erstarrungsrisse
KW - hochfester Stahl
PY - 2022
AN - OPUS4-54579
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Einfluss der Prozessführung auf den Eigenspannungszustand beim WAAM-Schweißen hochfester Stahlbauteile
N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein.
Im Rahmen der Normungssitzung werden praktikable Verarbeitungsempfehlungen basierend auf den Erkenntnissen des Vh. mit Vertretern aus Industrie und Forschung diskutiert.
T2 - NA 092-00-05 GA: Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)
CY - Online meeting
DA - 10.03.2022
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Kaltrisssicherheit
KW - Wärmeführung
KW - Windenergie
PY - 2022
AN - OPUS4-56722
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Joining technologies for hydrogen components: current need and future perspectives
N2 - The study provides an overview of the aspects of joining and its importance in manufacturing of components for the more and more important field of hydrogen as key factor for the energy transition to a decarburized future. To this end, the fundamentals of the technology fields of hydrogen production, storage, transport, and application are presented and the state of the art of manufacturing of components for hydrogen technologies by joining is summarized. Based on representative examples from practice, research and development, the importance of joining technology in hydrogen technologies is clearly highlighted and perspectives for the future are derived. From a macroeconomic perspective, the focal points, or trends of joining technologies here include: the erection of new infrastructure for hydrogen storage and transport, and the safe conversion of existing natural gas infrastructure and its challenges for welded materials. In addition, we show the problems that are anticipated with in-service repair welding of hydrogen pipelines. In hydrogen applications, the efficient mass production of fuel cells and electrolysers is becoming increasingly important. For that reason, the importance of additive manufacturing is highlighted. Finally, the challenges for technical regulations and standardization by using hydrogen are shown.
T2 - AJP 2023: 3rd International Conference on Advanced Joining Processes 2023
CY - Braga, Portugal
DA - 19.10.2023
KW - Hydrogen
KW - Infractstructure
KW - Joining
KW - Welding
KW - Research
PY - 2023
AN - OPUS4-58674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Treutler, K.
A1 - Schröpfer, Dirk
A1 - Wesling, V.
A1 - Kannengießer, Thomas
ED - da Silva, L. F. M.
ED - Martins, P. A. F.
ED - Reisgen, U.
T1 - Nickel-Iron-Alloy Modification to Enhance Additively Welded Microstructure for Subsequent Milling
N2 - The aerospace industry uses nickel–iron alloys, e.g., FeNi36, to create moulding tools for composite materials, since these alloys have a low coefficient of thermal expansion. Nickel–iron alloys are hard-to-cut materials. The moulding tools are large in size and involve complex structures, making them cost-intensive and difficult to manufacture. Thus, the focus is set on additive manufacturing, which can additionally enable the repair of components in order to eliminate local defects. However, the process usually results in a heterogeneous microstructure and anisotropic mechanical properties. As there is a high demand for a precise and exact fit of the precision moulds and the surface quality, the welded components must be subsequently machined. Additionally, inhomogeneous microstructure may lead to unstable cutting forces and conditions. Consequently, a modification of the microstructure morphology is achieved through specific alloy modifications in order to stabilise and improve the subsequent machining process. Therefore, titanium and zirconium are chosen as modification elements with a maximum 1% weight percent and are added to nickel–iron alloy powder. The elements are alloyed, and build-up welded by plasma-transferred-arcwelding. The resulting microstructure morphology of the welded wall structure and the machining properties are then determined. It can be shown that titanium has a significant effect on the structural morphology of the welded layers, as well as on the machining.
KW - Alloy modification
KW - Alloy 36
KW - Plasma-transferred arc welding
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
SN - 978-3-030-95463-5
DO - https://doi.org/10.1007/978-3-030-95463-5_6
SP - 85
EP - 99
PB - Springer
CY - Cham
AN - OPUS4-55484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Eissel, A.
T1 - 3. Sitzung des projektbegleitenden Ausschusses, 23.09.2021: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Im Laufe der Sitzung des projektbegleitenden Ausschusses (PbA) wurde der aktuelle Bearbeitungsstand sowie der Zeitplan vorgestellt. Darüber hinaus wurde mit dem PbA über die bereits erzielten Ergebnisse diskutiert. Abschließend wurde ein kurzer Ausblick über die zeitnah beginnenden Arbeiten beider Forschungseinrichtungen sowie ein Überblick über die vorhabenbezogenen Aufwendungen der Wirtschaft und des Ergebnistransfers in die Wirtschaft gegeben.
T2 - 3. Sitzung des Projektbegleitenden Ausschusses
CY - Online meeting
DA - 23.09.2021
KW - Projektbegleitender Ausschuss
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Schweißzusatzmodifikation
PY - 2021
AN - OPUS4-53637
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hensel, J.
T1 - Influence of build-up height and heat input on distortion and residual stresses in additive repair and modification of multi-material composites using DED-Arc
N2 - In hybrid additive manufacturing, components or semi-finished products manufactured by conventional primary forming are enhanced or modified by additive manufactured structures. The integration of additive manufacturing steps into existing production routes opens up significant economic and technical potential. However, systematic investigations focusing on the critical transition area between the specific properties of the substrate (like high-strength) and the additively manufactured component, made of specific filler material, are still lacking. Residual stresses heighten the risk of cold cracking, excessive distortion and a reduction in yield stress. This is particularly evident in sensitive transition areas, resulting from a complex interaction among the material used, process conditions, and component design. This risk can be minimized by an optimized layer structure in combination with suitable process parameters. The focus of the present study was to determine the influence of deposition strategy on t
T2 - International Materials Science and Engineering Congress - MSE 2024
CY - Darmstadt, Germany
DA - 02.04.2024
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2024
AN - OPUS4-61929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Increasing the Significance of Varestraint Tests through Improved Crack Evaluation
N2 - It was found that there is a systematic dependence of the crack growth on the welding parameters as well as on the load. Decreasing welding speeds with simultaneously higher heat input promote crack formation with increasing strain rate.
Based on the results, a new crack criterion was finally selected which allows an extended assessment of the material behavior during the MVT-test. The threshold introduced can quantify the dependencies of the crack formation on the welding and testing parameters, which could not be comprehensively described with the conventional evaluation. In principle, the evaluation routine can also be transferred to other Varestraint or externally loaded hot cracking tests.
T2 - IIW Intermediate Meeting Comission II-c
CY - Garching, Germany
DA - 06.03.2023
KW - Solidification cracking
KW - Varestraint-Test
PY - 2023
AN - OPUS4-57131
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Residual stress formation in DED-arc manufactured high strength steel components
N2 - Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
T2 - IIW Intermediate Meeting C-II/CIX
CY - Munich, Germany
DA - 06.03.2023
KW - Additive manufacturing
KW - High strength steel
KW - Residual stress
PY - 2023
AN - OPUS4-59307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Projektvorstellung FOSTA P1311: Beanspruchungsgerechte Reparatur von Schweiß-verbindungen bei der Fertigung von Bauteilen aushochfesten Feinkornbaustählen
N2 - Bei der Montage von Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich. Die Verarbeitungsregelwerke empfehlen das lokale thermische Ausfugen betroffener Bereiche und erneutes Schweißen, geben aber aufgrund fehlender wissenschaftlich fundierter Untersuchungen kaum Informationen zu adäquaten Reparaturkonzepten. Dies betrifft insbesondere die Berücksichtigung und Optimierung resultierender schweißbedingter Beanspruchungen durch hohe Schrumpfbehinderungen der Ausfugenuten sowie der Gefügedegradation angrenzender Bereiche durch das Ausfugen und erneute Schweißen. Gerade bei hochfesten Stahlgüten ergeben sich dadurch häufig reduzierte mechanische Eigenschaften und zusätzliche schweißbedingte Beanspruchungen sowie erneut auftretende Nahtdefekte.
Deshalb sind für das Forschungsvorhaben systematische bauteilrelevante Untersuchungen der schweißbedingten Beanspruchungen und Gefügeveränderungen reparierter Schweißnähte in Abhängigkeit von der Schrumpfbehinderung und Wärmeführung beim Schweißen und Ausfugen sowie von der Reparaturzyklenanzahl geplant, mit dem Ziel Empfehlungen für beanspruchungs- und werkstoffgerechte Reparaturkonzepte abzuleiten. Hierfür sind gerade Analysen an hochfesten Stahlgüten S500 für den Offshore-Bereich und S960QL für den Mobilkranbau interessant, die zur Errichtung und Fertigung hocheffizienter Konstruktionen wie Windenergieanlagen notwendig sind. Die Erkenntnisse bieten eine Grundlage für entsprechende Normen und Regelwerke. Damit können letztlich Schäden und zumeist teure Nacharbeiten verhindert und eine verbesserte Ausnutzung des hohen Festigkeitspotentials hochfester Stähle erreicht werden. Gerade auch KMU können mit Blick auf die Kosten für Fertigung, Schweißarbeit und Material von den Erkenntnissen beim Einsatz hochfester Stähle, die für eine effiziente Realisierung der Energiewende in Deutschland notwendig sind, profitieren
T2 - NA 092-00-05 GA (DVS AG Q 4/Q 4.1)
CY - Hamm, Germany
DA - 04.03.2020
KW - Reparatur
KW - Eigenspannungen
KW - Schweißen
KW - Wärmeführung
KW - Hochfester Feinkornbaustahl
KW - Gefügedegradation
PY - 2020
AN - OPUS4-51584
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Griesche, Axel
T1 - The Debye-Waller Factor for Temperature Distribution Determination in NBEI Experiments: A Case Study for GTAW
N2 - In Neutron-Bragg-Edge Imaging (NBEI) in situ experiments, we studied the phase transitions in martensitic steel sheets during butt-welding. Gas tungsten arc welding was used with a motorized torch allowing automated weldments. The austenitization in the heat affected zone underneath the welding head could be clearly visualized. Also, the retransformation into the martensitic phase upon cooling. However, we observed an unexpected additional change in transmission at λ = 0.44 nm that is at a wavelength larger than the wavelength of the Bragg edges of both the martensitic and austenitic phases. We attribute this change to the Deybe-Waller-Factor that describes the temperature dependence of coherent scattering at a crystal lattice. With help of temperature field simulations that were calibrated by the reading of anattached thermo couple during welding, we could show that the Debye-Waller factor can produce an additional image contrast.
T2 - SNI 2022
CY - Berlin, Germany
DA - 05.09.2022
KW - Welding
KW - Debys-Waller-Factor
KW - Neutron Imaging
PY - 2022
AN - OPUS4-55630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Heat control and design‑related effects on the properties and welding stresses in WAAM components of high‑strength structural steels
N2 - Commercial high-strength fller metals for wire arc additive manufacturing (WAAM) are already available. However, widespread industrial use is currently limited due to a lack of quantitative knowledge and guidelines regarding welding stresses and component safety during manufacture and operation for WAAM structures. In a joint research project, the process- and material-related as well as design infuences associated with residual stress formation and the risk of cold cracking are being investigated. For this purpose, reference specimens are welded fully automated with defned dimensions and systematic variation of heat control using a special, high-strength WAAM fller metal (yield strength>790 MPa). Heat control is varied by means of heat input (200–650 kJ/m) and interlayer temperature (100–300 °C). The ∆t8/5 cooling times correspond with the recommendations of fller metal producers (approx. 5–20 s). For this purpose, additional thermo-physical forming simulations using a dilatometer allowed the complex heat cycles to be reproduced and the resulting ultimate tensile strength of the weld metal to be determined. Welding parameters and AM geometry are correlated with the resulting microstructure, hardness, and residual stress state. High heat input leads to a lower tensile stress in the component and may cause unfavorable microstructure and mechanical properties. However, a sufciently low interlayer temperature is likely to be suitable for obtaining adequate properties at a reduced tensile stress level when welding with high heat input. The component design afects heat dissipation conditions and the intensity of restraint during welding and has a signifcant infuence on the residual stress. These complex interactions are analyzed within this investigation. The aim is to provide easily applicable processing recommendations and standard specifcations for an economical, appropriate, and crack-safe WAAM of high-strength steels.
KW - GMA welding
KW - Additive manufacturing
KW - Residual stresses
KW - High-strength steel
KW - Cold cracking safety
KW - Heat control
KW - Wind energy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567397
DO - https://doi.org/10.1007/s40194-022-01450-x
SN - 1878-6669
VL - 2022
SP - 1
EP - 11
PB - Springer
CY - Berlin
AN - OPUS4-56739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czeskleba, Denis
A1 - Nietzke, Jonathan
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Investigation of stress relief crack susceptibility of CrMoV steels coarse grain HAZ via simulation of uniaxial stress conditions during PWHT
N2 - Creep-resistant steels such as the 13CrMoV9-10, used in the construction of thick-walled pressure vessels, are most commonly submerged arc welded (SAW). These steels can develop stress relief cracks (SRC) if the mandatory post weld heat treatment (PWHT) is performed improperly. Current PWHT parameters, such as heating rate and holding time at a specific holding temperature, are based on both empirical experience and conventional free shrinking welding experiments to characterize the SRC-susceptibility of the weld. These cannot adequately depict the higher residual stresses caused by the structurally induced stiffness of the surrounding construction. This study discusses the development of a repeatable, precise, and time-efficient methodology to study the effects of different stress levels and heating rates on the SRC susceptibility of the coarse grain heat-affected zone (CGHAZ). For that purpose, samples were thermically treated to simulate a coarse grain heat-affected zone (CGHAZ) and subsequently exposed to representative levels of stress during the heating phase of a PWHT. The recorded stress and heating rate–dependent strains were mathematically analyzed via curve tracing/calculus to identify interdependent effects. This procedure facilitates the measurement of material characteristics such as carbide growth on grain boundaries at the µm-scale via an integrated value over the entire sample volume. The first and second derivatives show a slight, precipitate-dependent, increase in hardness of the sample, depending on the heating rate and applied stress. This new methodology generates an improved assessment of the SRC susceptibility of SAW microstructures of creep-resistant CrMoV steels.
KW - Submerged arc welding
KW - Creep-resistant steel
KW - Stress relief cracking
KW - Component-like test
KW - Post weld heat treatment
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576007
DO - https://doi.org/10.1007/s40194-023-01539-x
SN - 0043-2288
SP - 1
EP - 9
PB - Springer Nature
CY - Basel (CH)
AN - OPUS4-57600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Gustus, R.
A1 - Treutler, K.
A1 - Wesling, V.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Alloy modification for additive manufactured Ni alloy components—part I: effect on microstructure and hardness of Invar alloy
N2 - Alloy 36 (1.3912), also known as “Invar,” is an alloy with 36% nickel. The alloy has a remarkably low thermal expansion coefficient in certain temperature ranges. This peculiarity is called the invar effect, which was discovered in 1896 by the Swiss physicist Charles Édouard Guillaume. Therefore, it is used in applications in which dimensional stability is critical, such as molding tools for composite materials in aerospace, automotive applications, or liquified natural gas (LNG) cargo tanks. Moreover, increasingly complex structures and the optimization of resource efficiency also require additive manufacturing steps for the production or repair of components. Additively manufactured components have a heterogeneous microstructure and anisotropic mechanical properties. In addition, the manufactured components require subsequent machining surface finishing, like finish milling, to achieve their final contour. Nickel iron alloys are difficult to machine. Additionally, inhomogeneous microstructure may lead to unstable cutting forces and conditions. In part I of this investigation, the initial alloy 36 is modified with the elements Ti, Zr, and Hf up to a maximum of 0.33 wt.-%. The influence of the modification elements on the microstructure as well as on the hardness of the AM components is examined. Furthermore, one modification is applied to metal arc welding process and investigated. Part II focuses on the effect of the alloy modifications on machinability as well as on the surface integrity of plasma-transferred-arc-welded (PTA) and finish milled invar components.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - Alloy modification
KW - Alloy 36
KW - Plasma-transferred arc welding
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571777
DO - https://doi.org/10.1007/s40194-023-01510-w
SN - 0043-2288
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-57177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
T1 - Optimisation of surface residual stresses using ultrasonic‑assisted milling for wire‑arc additive manufactured Ni alloy components
N2 - Nickel alloys are cost intensive materials and generally classified as difficult-to-cut material. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. In this investigation, machining experiments were carried out on wire arc additive manufactured components made of alloy 36, varying the cutting speed and the feed rate. In addition, the conventional milling process (CM) was compared with a modern, hybrid machining process, the ultrasonic-assisted milling (US). The cutting forces and the surface-near residual stresses were analysed using X-ray diffraction. A significant improvement of the machinability as well as the surface integrity by using the ultrasonic assistance was observed, especially at low cutting speeds. The CM induced mainly tensile residual stresses, the US mainly compressive residual stresses.
KW - Surface integrity
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - Ni alloy
KW - Alloy 36
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575246
DO - https://doi.org/10.1007/s00170-023-11326-z
SN - 1433-3015
VL - 126
IS - 9
SP - 4191
EP - 4198
PB - Springer Nature
AN - OPUS4-57524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, Julien
A1 - Schröpfer, Dirk
A1 - Hamacher, M.
A1 - Michels, H.
A1 - Hamm, C.
A1 - Appelt, M.
A1 - Börner, Andreas
A1 - Kannengießer, Thomas
T1 - Tool development for hybrid finishing milling of iron aluminides
N2 - The importance of high-temperature materials made of iron aluminides (FeAl) has been increasing in light weight applications, e.g., airplane turbines, due to the high material’s specific strength. However, the highly economic production by means of permanent mold casting involves special microstructures for Fe26Al4Mo0.5Ti1B alloy components leading to difficult machinability for subsequent finishing milling and low surface qualities. Major effects of tool and machining parameter variation incorporating ultrasonic assistance on the milling process and surface integrity are shown. Loads for tool and component surface are significantly adjustable to enable an economic process chain regarding the surface integrity of safety-relevant components.
KW - Ultrasonic-assisted milling
KW - Iron aluminide
KW - Surface integrity
KW - Tool wear
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566294
DO - https://doi.org/10.1016/j.procir.2022.03.123
SN - 2212-8271
VL - 108
SP - 793
EP - 798
PB - Elsevier B.V.
AN - OPUS4-56629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schröpfer, Dirk
A1 - Becker, Amadeus
A1 - Kannengießer, Thomas
T1 - Kurzdarstellung der Projektergebnisse: Beanspruchungsgerechte Reparatur von Schweißverbindungen bei der Fertigung von Bauteilen aus hochfesten Feinkornbaustählen
N2 - Bei der Montage von Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich.
In einem Forschungsprojekt (FOSTA P1311) wurden Untersuchungen durchgeführt und Kenntnisse erarbeitet, um mittelfristig vor allem KMU beanspruchungsgerechte Reparaturkonzepte zur Verfügung zu stellen. Damit können letztlich Schäden und zumeist teure Nacharbeiten verhindert und eine verbesserte Ausnutzung des hohen Festigkeitspotentials hochfester Stähle erreicht werden. Gerade KMU können mit Blick auf die Kosten für Fertigung, Schweißarbeit und Material von den Erkenntnissen beim Einsatz hochfester Stähle, die für eine effiziente Realisierung der Energiewende in Deutschland notwendig sind, profitieren.
KW - MAG-Schweißen
KW - Hochfester Stahl
KW - Eigenspannungen
KW - Thermisches Ausfugen
KW - Reparaturschweißen
KW - Gefügedegradation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555822
SP - 1
EP - 2
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-55582
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Kromm, Arne
A1 - Mente, Tobias
A1 - Brackrock, Daniel
A1 - Czeskleba, Denis
A1 - Kannengießer, Thomas
T1 - Component test for the assessment of delayed hydrogen-assisted cracking in thick-walled SAW joints for offshore applications
N2 - Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods, or jackets. These components are typically constructed using submerged arc welding (SAW) with high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen-assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicates the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam/layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled with over 20 passes and a seam length of 1000 mm. Additional welded stiffeners simulated the effect of a high restraint, to achieve critical HAC conditions. The necessity of a minimum waiting time (MWT) before the NDT can be conducted (to exclude HAC) was critically verified by the application of ultrasonic testing of the welded joint at different time-steps of the NDT of up to 48 h after the completion welding. The residual stresses were determined by a robot XRD goniometer. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modeling allowed the qualitative estimation of the hydrogen diffusion in the weld. No noticeable HAC occurrence was identified and confirms the high cracking resistance of the investigated material. Finally, the applicability of the MWT concept should be critically discussed.
KW - Hydrogen
KW - Cold cracking
KW - Minimum Waiting Time
KW - Offshore steel grade
KW - Component test
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591981
DO - https://doi.org/10.1007/s40194-023-01658-5
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-59198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wandtke, Karsten
ED - Becker, Amadeus
ED - Schröpfer, Dirk
ED - Kromm, Arne
ED - Kannengießer, Thomas
ED - Scharf-Wildenhain, R.
ED - Hälsig, A.
ED - Hensel, J.
T1 - Residual Stress Evolution during Slot Milling for Repair Welding and Wire Arc Additive Manufacturing of High-Strength Steel Components
N2 - High-strength steels offer potential for weight optimization due to reduced wall thicknesses in modern constructions. Additive manufacturing processes such as Wire Arc Additive Manufacturing (WAAM) enable the resource-efficient production of structures. In the case of defects occurring in weld seams orWAAM components due to unstable process conditions, the economical solution is local gouging or machining and repair welding. It is important to understand the effects of machining steps on the multiaxial stress state in conjunction with the design-related shrinkage restraints. Research into how welding and slot milling of welds andWAAM structures affects residual stresses is still lacking. For this reason, component-related investigations with high-strength steels with yield strengths ≥790 MPa are carried out in our research. In-situ digital image correlation (DIC) and ex-situ X-ray diffraction (XRD) were used to analyze the stresses and strains induced on specimens during and after milling. The systematic analyses revealed a significant interaction of the stiffness and microstructure of the specimens with the initial residual stresses induced by welding. Subsequent repair welds can result in significantly higher residual stresses.
KW - High strength steels
KW - Additive manufacturing
KW - Residual stress
KW - Repair welding
KW - Ditigtal image correlation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593515
DO - https://doi.org/10.3390/met14010082
VL - 14
IS - 1
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-59351
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Fertigungsbedingte Beanspruchungen und Kaltrisssicherheit in generativ gefertigten Bauteilen aus hochfesten Feinkornbaustählen - Kurzdarstellung der Projektergebnisse, FOSTA P1380
N2 - Die Verwendung hochfester Feinkornbaustähle hat für viele Anwendungen des Stahlbaus ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen mit ho-her mechanischer Beanspruchbarkeit. Weitere Zugewinne an Effizienz sind durch generative Fertigungsschritte sowie bionische Bauweisen erzielbar. Hierzu stehen bereits kommerzielle hochfeste drahtförmige Zusatzwerkstoffe für formgebendes MSG-Schweißen zur Verfügung. Dem Einsatz stehen noch fehlende quantitative Aussagen zu den fertigungsbedingten Beanspruchungen und der Bauteilsicherheit während Herstellung und Betrieb im Wege. Dies betrifft insbesondere prozess- sowie materialbedingte Einflüsse und die konstruktive Schrumpfbehinderung verbunden mit der Ausbildung hoher Zugeigenspannungen und damit zusammenhängenden Kaltrissbildung.
Hierfür wurden im Projekt detaillierte und anwenderbezogene Kenntnisse zu den komplexen Wechselwirkungen zwischen Schweißprozess und Wärmeführung während der Fertigung, der metallurgischen Vorgänge und insbesondere der vorliegenden konstruktiven Einflüsse auf die entstehenden Eigenspannungen erarbeitet, um ein frühzeitiges Bauteilversagen aufgrund eines hohen fertigungsbedingten Beanspruchungsniveaus bis hin zu einer Rissbildung während der Fertigung sicher zu vermeiden. Gleichzeitig wurden die Einflüsse auf die mechanisch-technologischen Gütewerte systematisch analysiert. Zudem wurden die Auswirkungen trennender Verfahren durch Entfernen der Substratplatte sowie durch die spanende Bearbeitung der Vorformlinge zu Endbauteilgeometrien geklärt, da diese unmittelbar den Eigenspannungszustand beeinflussen und deutlichen Verzug der Bauteile auslösen.
Für das generative Schweißen konnten Verarbeitungsempfehlungen sowie Normenvorgaben erarbeitet werden. Dies hilft insbesondere KMU eine wirtschaftliche, beanspruchungsgerechte und risssichere generative Fertigung von Bauteilen aus hochfesten Feinkornbaustählen zu ermöglichen.
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Kaltrisssicherheit
KW - Hochfester Stahl
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582198
N1 - Das IGF-Vorhaben IGF-Nr. 21162 BG (P 1380) "Fertigungsbedingte Beanspruchungen und Kaltrisssicherheit in generativ gefertigten Bauteilen aus hochfesten Feinkornbaustählen" der Forschungsvereinigung Stahlanwendung e. V. wurde über die AiF im Rahmen des Programms zur Förderung der Industriellen Gemeinschaftsforschung (IGF) vom Bundesministerium für Wirtschaft und Klimaschutz aufgrund eines Beschlusses des Deutschen Bundestages gefördert.
SP - 1
EP - 2
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-58219
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Witte, Julien
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Stresses in repair welding of high-strength steels—part 1: restraint and cold cracking risk
N2 - AbstractThe sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures, like mobile or ship cranes. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of global and local welding-induced stresses may lead to crack formation and component failure, particularly in interaction with the degradation of the microstructure and mechanical properties of high-strength steels during the repair process. However, manufacturers hardly have any information about these issues and there is a lack of recommendations and guidelines to take these safety-relevant aspects into account in adequate repair concepts. The aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines to avoid cold cracking, damage and expensive reworking especially for high-strength steels. Part 1 of this study involves systematic investigations of influences of shrinkage restraint during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures. The quantification of the shrinkage restraint of repair weld joints was achieved by means of experimental and numerical restraint intensity analysis. In welding experiments with self-restrained slot specimens, restraint intensity and introduction of hydrogen via the welding arc using anti spatter spray were varied systematically to analyse the effect on welding result, residual stresses and cold cracking. It could be shown that increasing restraint intensities result in significantly higher transverse residual stress levels. In the case of hydrogen introduction S500MLO showed no cold cracking independent of the restraint conditions. However, S960QL was found to be considerably cold cracking sensitive if hydrogen is introduced. With increasing restraint intensity length and number of cold cracks increases significantly. Part 2 [1] of this study is focussed on microstructure and residual stresses due to gouging and stress optimization via adequate heat control parameters in repair welding.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595212
DO - https://doi.org/10.1007/s40194-024-01691-y
SN - 0043-2288
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-59521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Witte, Julien
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Stresses in repair welding of high-strength steels—part 2: heat control and stress optimization
N2 - In welding of high-strength steels, e.g. for foundations and erection structures of wind energy plants, unacceptable defects can occasionally be found in the weld area, which should be removed by thermal gouging and subsequent re-welding. High shrinkage restraint of repair welds may lead to crack formation and component failure, predominantly in interaction with degraded microstructures and mechanical properties due to repair cycles. This study aims for elaboration of recommendations for repair concepts appropriate to the stresses and materials involved to avoid cold cracking, damage and expensive reworking. In part 1 [1] of this study, systematic investigations of influences of shrinkage restraint on residual stresses and cold cracking risk during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures were focussed. In this part 2, the microstructure, particularly hardness, and residual stresses due to gouging and influences of heat control parameters in repair welding are analysed. A clear reduction in residual stress after gouging can be observed, especially for the specimens with restrained transverse shrinkage. Gouging to a depth of approx. 2/3 of the seam height does not lead to a complete relaxation of the observed reaction forces. Particularly for the higher strength steel S960QL, there are pronounced areas influenced by the gouging process in which a degradation of the microstructure and properties should be assumed. Overall, the repair welds show a significant increase in the width of the weld and HAZ compared to the original weld, especially in the case of S960QL/G89. The repair welds show higher welding-induced stresses than the original welds, especially in the areas of the HAZ and the base metal close to the weld seam. This behaviour can be attributed overall to increased restraint conditions due to the remaining root weld or shorter gouge grooves. In good agreement with earlier investigations, the residual stresses transverse to the weld can be significantly reduced by upwardly limited working or interpass temperatures, and the reaction stresses resulting from high restraint conditions can be effectively counteracted. The influence of the heat input on the stress formation is low compared to the interpass temperature for both test materials.
KW - Repair-welding
KW - Wind Energy
KW - High-strength steels
KW - Cold cracking
KW - Residual stresses
KW - Offshore steels
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600259
DO - https://doi.org/10.1007/s40194-024-01731-7
SN - 0043-2288
SP - 1
EP - 15
PB - Springer Nature
AN - OPUS4-60025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Willeke, Maraike
A1 - Giese, Marcel
A1 - Lorenz, Swenja
A1 - Treutler, Kai
A1 - Schröpfer, Dirk
A1 - Wesling, Volker
A1 - Kannengießer, Thomas
T1 - Effect of alloy modification on the wear protection coatings made of Ni- and Co-based materials and surface machinability via ultrasonic milling process
N2 - AbstractWear-resistant coatings are required for highly efficient and economical steel components in equipment, process, and power plant engineering to withstand high corrosive, tribological, thermal, and mechanical stresses. Co-alloys are used as wear-resistant coatings for steel components, tailored to the specific application. The substitutability of Co alloys with Ni-based wear protection systems, in addition to price and supply uncertainties, is facilitated by the combination of innovative welding and machining processes such as ultrasonic-assisted milling. The aim of the study is to improve the machinability of two different hard-facing alloys while maintaining the same wear protection potential. Therefore, the wear-resistant alloys NiMoCrSi (Colmonoy C56) and CoMnCrSi (Tribaloy T400) were modified by the alloying additions Nb, Hf, and Ti and then applied to a carbon-manganese steel S355 using the plasma transfer arc (PTA) welding process. The influence of the alloying additions on the microstructure as
KW - Wear resistance
KW - Co-based alloy
KW - Ni-based alloy
KW - PTA welding process
KW - Ultrasonic assisted milling process
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623931
DO - https://doi.org/10.1007/s00170-024-14955-0
SN - 0268-3768
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-62393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giese, Marcel
A1 - Gräbner, Maraike
A1 - Schröpfer, Dirk
A1 - Treutler, Kai
A1 - Lorenz, Svenja
A1 - Kannengießer, Thomas
A1 - Wesling, Volker
T1 - Alloy modification and ultrasonic-assisted milling of wear-resistant alloys with defined surfaces
N2 - The reduction of CO2 emissions is closely linked to the development of highly efficient and economical steel components in plant and process engineering. To withstand the high combined corrosive, tribological, thermal, and mechanical stresses, wear-resistant coatings tailored to the application and steel grade are used. In addition to the increasing demand to substitute conventional cobalt alloys with nickel alloys, there is also a growing need for defined or functional surfaces of high integrity. Due to high tool wear, milling operations required to produce the complex geometries of the components are often not economically feasible for SMEs. By means of alloy modification of the filler metals for nickel-based plasma build-up welded wear-resistant coatings and by the use of innovative ultrasonic-assisted milling processes more favourable machinability shall be achieved without reducing the wear protection potential. In this paper, the influence of the microstructure and precipitation morphology adjusted by means of alloy modification on the machinability is investigated. This is done based on a wear protection alloy NiCrMoSiFeB (trade name: Colmonoy 56 PTA) typically used for screw machines, which substitutes conventional CoCr alloys (Stellite). Metallurgical investigations and in-situ measurements of occurring process forces and temperatures at the tool cutting edge during milling as well as subsequent investigations of tool wear and surface integrity allow a detailed analysis and correlation between microstructural properties and machinability. For the cast samples, a clear change in the microstructure and hardness can be seen through the addition of Al, Ti, or Nb. These differences lead to an improvement in the machining process for Nb. Al and Ti cause long-needled or star-shaped precipitations and hardness increases, which lead to higher cutting forces and increased tool wear.
KW - Cladding
KW - Wear resistant alloys
KW - Alloy modification
KW - Post-processing
KW - Ultrasonic assisted milling
KW - Renewable energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622918
DO - https://doi.org/10.1007/s40194-024-01786-6
SN - 1878-6669
VL - 68
SP - 2567
EP - 2575
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-62291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Evaluation of local strain behavior of cross-weld tensile specimens of micro-alloyed high-strength steels by digital image correlation
N2 - Microalloying elements such as Nb and Ti play a decisive function in achieving the desired mechanical strength of quenched and tempered, high-strength fine-grain structural steels with a nominal yield strength ≥ 690 MPa. The current specifications for the chemical composition only provide manufacturers with upper limits. However, even minor deviations in the alloy concept can have a significant impact on the mechanical properties. Consequently, accurate prediction of weldability and the integrity of welded joints becomes difficult or even impossible due to differences in composition and the resulting microstructures. Undesirable consequences include a possible softening of the heat-affected zone (HAZ) or, conversely, hardening effects. In view of these challenges, various microalloying strategies with different Ti and Nb contents are being systematically investigated for the first time using specially developed laboratory casting alloys. Each alloying route is based on the common S690QL, maintaining both the chemical composition and the heat treatment parameters. To analyse the weldability, three-layer welds were performed using gas metal arc welding (GMAW) and critical microstructures, such as areas of the heat-affected zone (HAZ) that exhibit significant softening or hardening, were identified. The effect of the softened HAZ region on failure was evaluated using transverse tensile specimens. Digital image correlation (DIC) is used to image changes in local strains in different HAZ regions in situ. Using a specially developed mirror system, the local strains of the microstructure zones on the top and bottom of the weld are recorded simultaneously. This makes it possible to analyse how the weld seam geometry (e.g., V-seam) influences the strain gradients. In addition, the analysis of the local deformation helps to understand the effects of the softened HAZ on the global strain, the fracture constriction, the fracture position, and the overall fracture behavior.
T2 - IIW Intermediate Meeting, Com. II-A
CY - Incheon, Republic of Korea
DA - 12.03.2024
KW - Welding
KW - High-strength steel
KW - Alloy concept
KW - Cross-weld tensile sample
KW - Mechanical properties
PY - 2024
AN - OPUS4-59675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Welding of in service hydrogen pipelines for repair and maintenance purposes Concepts and Challenges
N2 - Hydrogen will make a decisive contribution to a sustainable large-scale energy supply, the transport of which will be based on long-distance pipeline grids. Previous material compatibility studies have shown that the currently used low-alloy pipe steels are generally suitable for hydrogen pipelines. However, this cannot be directly transferred to the case of repair welding. For technical and economic reasons, welding work on hydrogen pipelines in service is usually carried out during operation under continuous pressure and gas flow. In this context, concepts such as hot tapping and stoppling are well established in natural gas (NG) grids and crude oil transportation. In hot tapping, a pressurized pipeline is drilled by flanging a sealed, pressure-tight system consisting of a shut-off valve and drilling equipment. For this purpose, sleeves (made of preformed cylindrical half-shells) must be welded by longitudinal seams and then welded to the product-carrying pipeline by circumferential girth welds. Preheat temperatures of approximately 100 °C must be maintained for most manual metal arc (MMA) / shielded metal arc welding (SMAW) and 250 °C for the interpass temperature in multi-pass welding. This is particularly important for thin-walled pipelines because the austenitizing temperature is exceeded on the inside of the pipeline when the girth welds are welded. As a result, significantly higher hydrogen absorption in the pipeline steel is expected, with possible degradation of mechanical properties or cracking.
T2 - MSE 2024: International Materials Science and Engineering Congress
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Hydrogen
KW - Repair welding
KW - Pipelines
KW - In-service
PY - 2024
AN - OPUS4-61155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Influence of residual stresses and heat control on stress relief cracking in a CrMoV steel mockup
N2 - Preventing failures in the manufacture or operation of petrochemical reactors made from creep-resistant, low-alloy steels such as 13CrMoV9-10 still requires research, despite over 60 years of investigation into the field of stress relief cracking. Welding this steel grade requires care. This is due to its low toughness and high strength in the welded condition if not heat treated after welding, combined with an increased susceptibility to cracking during stress relaxation. Previous research on cracking in creep resistant steels has focused on thermal and metallurgical factors; however, little knowledge has been gained on cracking under real-life restraint conditions. In this work, the influence of welding heat control on cracking was investigated by simulating the manufacturing conditions prevailing in the construction of petrochemical reactors using a special weld mockup. The application of acoustic emission analysis showed that cracks formed during post-weld heat treatment in a temperature range between 300 °C and 500 °C. Compared to small scale samples, the toughness of the restrained welds was significantly lower. SEM and TEM analyses of all samples revealed early ageing due to early precipitation of special carbides during post-weld heat treatment under restraint. Neutron diffraction experiments showed that the residual stresses in the weld seam reach the yield point of the material. The presentation provides an overview of how a comprehensive assessment of the integrity of submerged arc welded CrMoV steels can be achieved in the laboratory.
T2 - Cracking Phenomena in Welding and Additive Manufacturing 2025
CY - Trollhättan, Sweden
DA - 12.03.2025
KW - CrMoV
KW - Stress Relief Cracking
KW - Sub-merged arc welding
PY - 2025
AN - OPUS4-62783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Modification of CoCr alloys to optimize of additively welded microstructures and subsequent surface finishing
N2 - Due to increasing requirements relating to the efficiency of highly stressed components in turbine or plant construction, the use of cost-intensive, difficult to process materials is increasingly necessary today. In this context, cobalt-chromium alloys in particular are highly resistant to thermal and mechanical stress, as well as to corrosive and abrasive loads. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components in many sectors. In order to realise a homogeneous and isotropic microstructure, alloy modifications are made to the alloy CoCr26Ni9Mo5W. For this purpose, hafnium and zirconium are added at 1 % and 0,33 % by mass each, as these elements are supposed to have a positive effect on the microstructure morphology. Plasma-Transferred-Arc is used for the welding tests. Wall structures are welded by multiple single-layer, overlapping welding beads on low-alloyed steel substrate (S355). The results show that the alloying elements hafnium and zirconium have a clear influence on the microstructure. Hardness measurements were also carried out. With each modification, the hardness is increased compared to the original material. The machining analyses show a reduction in cutting forces using ultrasonic assisted milling for high cutting speed and low feed rate.
T2 - 2021 Intermediate meeting of C IX NF
CY - Online meeting
DA - 09.03.2021
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Plasma-Transferred-Arc
KW - Filler metal modification
KW - Additive manufacturing
PY - 2021
AN - OPUS4-52356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Michael, Thomas
T1 - Konstruktive Einflüsse bei der beanspruchungsgerechten Reparatur geschweißter Bauteile aus hochfesten Feinkornbaustählen
N2 - Für eine nachhaltige und ressourceneffiziente Fertigung von Windkraftanlagen ist der Einsatz moderner hochfester Feinkornbaustähle vielfach notwendig. Bei der Montage hochfester Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich. Derzeitige Normen und Verarbeitungsrichtlinien geben hierbei kaum Informationen zu adäquaten Reparaturkonzepten, insbesondere für hochfeste Stähle. Vor diesem Hintergrund werden an der Bundesanstalt für Materialforschung und -prüfung (BAM) bauteilrelevante Untersuchungen zu den schweißbedingten Beanspruchungen und Gefügeveränderungen bei der schweißtechnischen Reparatur durch lokales thermisches Ausfugen und erneutes Schweißen durchgeführt.
Hierzu werden einige wesentliche Ergebnisse an Beispielen des Ingenieurbaus, mit Blick auf die mechanisch-technologischen Eigenschaften und Eigenspannungen erörtert. In einem aktuellen Vorhaben (FOSTA P1311, IGF 20162N) sind darauf aufbauend die Einflüsse durch die Schrumpfbehinderung und Wärmeführung beim Reparaturschweißen hochfester Feinkornbaustähle (S500MLO, S960QL) sowie die Reparaturzyklenanzahl Fokus systematischer Untersuchungen. Mittels strukturmechanischer Berechnungen ließen sich hierzu selbstbeanspruchende Probenformen identifizieren, die unterschiedliche definierte Steifigkeitsverhältnisse von Reparaturschweißnähten realer Bauteile abbilden. Schweißnähte an diesen bauteilähnlichen Proben weisen signifikant erhöhte schweißbedingte Beanspruchungen mit zunehmenden (Biege-)Einspanngraden auf. Im Vergleich mit bisherigen Erkenntnissen wird gezeigt, dass eine sichere Reparatur solcher Schweißnähte nur mittels optimaler Reparaturkonzepte und Wärmeführung gelingt, um diesen hohen Beanspruchungen und auch den speziellen Gefügen hochfester Stähle Rechnung zu tragen.
Ziel der Untersuchungen ist es letztlich, Empfehlungen für beanspruchungs- und werkstoffgerechte Reparaturkonzepte gerade für KMU abzuleiten, um Schäden und zumeist teure Nacharbeiten zu vermeiden.
T2 - 4. Niedersächsisches Symposium Materialtechnik
CY - Online meeting
DA - 25.02.2021
KW - Eigenspannungen
KW - Gefügedegradation
KW - Hochfester Feinkornbaustahl
KW - Reparatur
KW - Schweißen
PY - 2021
SN - 978-3-8440-8021-6
SN - 2364-0804
VL - 10
SP - 488
EP - 501
PB - Shaker Verlag
CY - Düren
AN - OPUS4-53315
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
A1 - Treutler, K.
A1 - Wesling, V.
A1 - Engelking, Lorenz
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Modifikation von CoCr-Legierungen für die additive lichtbogenbasierte Fertigung
N2 - Für Komponenten im Turbinen- oder Anlagenbau werden aufgrund ihrer Eigenschaften häufig Kobalt-Chrom-Legierungen verwendet. Diese weisen eine hohe Korrosionsbeständigkeit und hohen Verschleißwiederstand auf. Aufgrund der komplexen Strukturen und dem Bestreben nach Ressourceneffizienz wird zur Herstellung der Komponenten die additive Fertigung verwendet. Hierbei sind hinsichtlich der Inhomogenität und Anisotropie der Gefüge und deren Eigenschaften weitere Kenntnisse notwendig. Bei den vorliegenden Belastungen liegt ein erhöhter Anspruch an die Oberflächenintegrität vor, welcher durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten sichergestellt wird. Dabei sind gerade Co-Cr-Legierungen wegen der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ausgehend von dieser Problemstellung erfolgt im Zuge eines Gemeinschaftsvorhabens des ISAF in Kooperation mit der BAM eine gezielte Beeinflussung des Gefüges. Ziel des Projektes ist die Zusammenhänge zwischen verschiedenen Legierungsmodifikationen, der entstehenden Gefügemorphologie und den Zerspanungseigenschaften von Co- Cr-Legierungen für die additive Fertigung mittels PTA darzustellen. Der Fokus liegt auf dem Beheben der bestehenden Nachteile bei gleichzeitigem Aufrechthalten der besonderen Eigenschaften der Legierung. Durch das Hinzulegieren von variierenden Gehalten von Zirkonium und Hafnium wird die Gefügeveränderung eingestellt. Es hat sich gezeigt, dass Hafnium als zusätzliches Legierungselement einen deutlichen Einfluss auf die Gefügemorphologie hat. Darüber hinaus wird die Auswirkung der Legierungsmodifikation auf die Härte und die Zerspanbarkeit dargestellt.
T2 - 42. Assistentenseminar der Wissenschaftlichen Gesellschaft Fügetechnik e.V.
CY - Blankenau, Germany
DA - 06.10.2021
KW - Legierungsmodifikation
KW - ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2022
SN - 978-3-96144-210-2
VL - 385
SP - 103
EP - 113
PB - DVS Media GmbH
AN - OPUS4-56658
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Additive Manufacturing of Iron Aluminides: Microstructure, Machinability, and Surface Integrity
N2 - The increasing global focus on energy and resource efficiency has stimulated a growing interest in additive manufacturing. AM offers economic advantages and enables an efficient use of materials. However, AM components often require subsequent mechanical post-processing, such as machining (e.g. milling), to achieve the final contours or surfaces. This is a particular challenge due to the heterogeneous and anisotropic nature of AM structures, which affect machining and the resulting component properties. High-performance materials such as iron aluminide represent a promising alternative to conventional high-temperature materials with a significant economic advantage. However, the strength and hardness properties, which are advantageous for applications in highly stressed lightweight components, pose a challenge for economical machining in addition to the AM microstructure properties. The difficult-to-cut material causes accelerated tool wear and insufficient surface quality. This study shows that crack-free additive manufacturing of the three-component system of iron-nickel-aluminum is possible and advantages in terms of machinability compared to FeAl-AM components are achieved. The more homogeneous microstructure leads to a reduction in cutting forces, with positive effects on the machinability and optimized surface integrity. Ultrasonic assisted milling (USAM) offers great potential to address the major challenges posed by difficult-to-cut materials and additively manufactured weld structures. Therefore, this study focuses on assessing the transferability of previous positive results by USAM to the selected iron aluminide alloys. The machinability of the aluminides is analyzed by varying significant influencing variables in finish milling experiments and evaluated in terms of the loads on the tool and the resulting surface integrity.
T2 - 77. IIW Annual International Conference
CY - Rhodos, Greece
DA - 07.07.2024
KW - Additive manufacturing
KW - Surface-integrity
KW - Iron-aluminide
KW - Ultrasonic-assisted milling
KW - Difficult-to-cut
KW - Tool wear
PY - 2024
AN - OPUS4-62027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Joining technology for the new hydrogen economy: Current need and future perspectives
N2 - This presentation gives an overview on the importance of joining processes for component fabrication in hydrogen technologies. For that reason, the current need and future research and developement activites are highlighted for the three technological fields: hydrogen storage, transport and use (in terms of the emerging field of additive manufacturing). Finally, some remarks are given for necessary changes in the standardization.
T2 - Laser Colloquium Hydrogen 2024
CY - Aachen, Germany
DA - 10.09.2024
KW - Hydrogen technologies
KW - Joining
KW - Welding
KW - Challenges
KW - Standardization
PY - 2024
AN - OPUS4-61012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
T1 - Vorstellungsvortrag: "H2-SuD" - Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2-Ferngasleitungen
N2 - Zur Umsetzung der wasserstoffbasierten Energiewende ist eine zuverlässige Transportinfrastruktur unverzichtbar. Hierfür ist die Nutzung großer Teile des vorhandenen Erdgasnetzes vorgesehen. Im Rahmen von Reparatur- und Wartungsarbeiten ist das Schweißen im Betrieb an Erdgaspipelines Stand der Technik. In Verbindung mit Wasserstoff wirft diese Technik jedoch Fragen der Materialverträglichkeit auf. Das im Vortrag vorgestellte Projekt H2SuD leistet Beiträge zur Aufklärung des Einflusses von Reparaturschweißprozessen auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen. Ein Schwerpunkt des Vortrages liegt auf der im Projekt erarbeiteten Prüfmethode für Modellversuche, mit denen der Einfluss von Schweißen im Betrieb an Pipelines auf die Wasserstoffaufnahme getestet wird. Die Durchführung erster Versuche und dabei erzielte Ergebnisse werden präsentiert.
T2 - Bacheloranden-, Masteranden-, Doktoranden Kolloquium (BMDK) OvGU Magdeburg
CY - Magdeburg, Germany
DA - 17.01.2024
KW - Pipeline
KW - Prüfverfahren
KW - Schweißen
KW - Reparatur
KW - Wasserstoff
PY - 2024
AN - OPUS4-59447
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ebell, Gino
T1 - Risiko der Wasserstoffentwicklung an martensitischen Schraubankern unter baupraktischen Bedingungen
N2 - Die vorliegende Untersuchung beschäftigt sich mit der Fragestellung ob unter praxisrelevanten Bedingungen die Entstehung von Wasserstoff an vollmartensitischen Schraubankern möglich ist. Im Gegensatz zu austenitischen Werkstoffen besteht bei martensitischen Werkstoffen bei Gegenwart von Wasserstoff stets die Möglichkeit einer wasser-stoffinduzierten Versprödung des Materials. Hierfür wurde ein in der Praxis häufig anzutreffendes Szenario gewählt, das ein galvanisches Element, bestehend aus nichtrostenden Schraubankern (in diesem Fall martensitischen) und einer verzinkten Ankerplatte an einem Betonkörper, umfasst. Zum Nachweis einer Wasserstoffentwicklung wird der Elementstrom zwischen den Bauteilen sowie das Korrosionspotential erfasst. Die Ergebnisse der Versuche zeigen, dass über eine zeitlich begrenzte Dauer eine starke kathodische Polarisation der martensitischen Schraubanker durch die korrosive Auflösung des Zinks erfolgt. Als Folge kommt es zur Wasserzersetzung im Phasengrenzbereich der Schraubanker und zur Entstehung von atomarem Wasserstoff. Das berechnete Gasvolumen des entstandenen Wasserstoffs an den Stahlankern wurde bestimmt und lag im Mittel bei 11,14 ± 1,94 ml. Eine Diffusion des an der Stahloberfläche adsorbierten Wasserstoffs in den martensitischen Werkstoff ist somit theoretisch möglich und impliziert eine mögliche Gefährdung durch wasserstoffinduzierte Rissbildung und spontanem Versagen unter Belastung.
T2 - Arbeitskreis Korrosionsschutz im konstruktiven Ingenieurbau
CY - Online meeting
DA - 24.09.2020
KW - Korrosion
KW - Wasserstoff
PY - 2020
AN - OPUS4-51309
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Effects of inter layer time and build height on resulting properties of 316L stainless steel processed by laser powder bed fusion
N2 - Das pulverbettbasierte selektive Laserstrahlschmelzen (engl. laser powder bed fusion, L-PBF) ist die am weitesten verbreitete additive Fertigungstechnologie für die Herstellung metallischer Komponenten. Unter der Vielzahl an Einflussfaktoren auf die Qualität und die mechanischen Eigenschaften von L-PBF-Bauteilen hat die Zwischenlagenzeit (engl. inter layer time, ILT) bisher kaum Beachtung in der wissenschaftlichen Literatur gefunden, obwohl sie je nach Bauraumausnutzungsgrad stark variieren kann. In diesem Vortrag werden Ergebnisse einer Studie präsentiert, die den Einfluss der ILT in Kombination mit der Bauteilhöhe und unter Berücksichtigung verschiedener Volumenenergiedichten am Beispiel der austenitischen Stahllegierung AISI 316L untersucht. Die Fertigungsprozesse wurden in-situ mittels Thermographiekamera überwacht. Auf diese Weise konnten intrinsische Vorerwärmungstemperaturen während der Bauteilfertigung lagenweise extrahiert werden. Es wurden signifikante Effekte der ILT und der Bauteilhöhe auf Wärmeakkumulation, Mikrostruktur, Schmelzbadgeometrie und Härte festgestellt. Ferner konnte ein Anstieg von Defektdichten bei einem gegenseitigen Wechselspiel aus Bauteilhöhe und ILT aufgezeigt werden. Die Zwischenlagenzeit wurde somit als kritischer Faktor für die L-PBF-Fertigung von Realbauteilen identifiziert.
T2 - 74th IIW Annual Assembly and International Conference
CY - Online meeting
DA - 07.07.2021
KW - Additive Manufacturing
KW - Laser powder bed fusion
KW - In-situ process monitoring
KW - Thermography
KW - Preheating temperature
KW - Inter layer time
PY - 2021
AN - OPUS4-52954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Thickness and microstructure effect on hydrogen diffusion in creep-resistant 9 % Cr P92 steel and P91 weld metal
N2 - Martensitic 9 %-Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. The small number of available diffusion coefficients varies already at room temperature by several orders of magnitude (mostly regarded as result of present microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. The diffusion coefficients are calculated by two methods (time-lag and inflection point method) were performed. The results show that, despite of microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients.
T2 - IIW Annual Assembly, Meeting of Commission IX-C
CY - Online meeting
DA - 15.07.2021
KW - Creep-resistant steel
KW - Diffusion
KW - Electrochemical permeation
KW - Hydrogen
KW - Welding
PY - 2021
AN - OPUS4-53048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Hydrogen embrittlement of steels
N2 - Hydrogen assisted cracking of metals is a serious issue in the safety of components, espcially in case of welding. The current presentation gives an overview on specialized testing procedures at Department 9 including the quantitative determination of hydrogen.
T2 - HYDROGENIUS BAM Joint Hydrogen Symposium
CY - Online meeting
DA - 06.07.2021
KW - Hydrogen
KW - Embrittlement
KW - Degradation
KW - Carrier gas hot extraction
KW - Welding
PY - 2021
AN - OPUS4-53049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Heat control and design-related effects on the properties and welding stresses in WAAM components of high-strength structural steels
N2 - Commercial high-strength filler metals for wire arc additive manufacturing (WAAM) are already available. However, widespread industrial use is currently limited due to a lack of quantitative knowledge and guidelines regarding welding stresses and component safety during manufacture and operation for WAAM structures. In a joint research project (FOSTA-P1380/IGF21162BG), the process- and material-related as well as design influences associated with residual stress formation and the risk of cold cracking are being investigated. For this purpose, reference specimens are welded fully automated with defined dimensions and systematic variation of heat control using a special, high-strength WAAM filler metal (yield strength >790 MPa). Heat control is varied by means of heat input (200–650 kJ/m) and interlayer temperature (100–300 °C). The ∆t8/5 cooling times correspond with the recommendations of steel producers (approx. 5–20 s). Welding parameters and AM geometry are correlated with the resulting microstructure, hardness and residual stress state. High heat input leads to a lower tensile stress in the component and may cause unfavorable microstructure and mechanical properties. However, a sufficiently low interlayer temperature is likely to be suitable for obtaining adequate properties at a reduced tensile stress level when welding with high heat input. The component design affects heat dissipation conditions and the intensity of restraint during welding and has a significant influence on the residual stress. These complex interactions are analyzed within this investigation. The aim is to provide easily applicable processing recommendations and standard specifications for an economical, appropriate and crack-safe WAAM of high-strength steels.
T2 - Third edition of the International Congress on Welding, Additive Manufacturing and associated non destructive testing
CY - Online meeting
DA - 08.06.2022
KW - MAG-Schweißen
KW - Eigenspannungen
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Kaltrisssicherheit
PY - 2022
AN - OPUS4-56710
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Hydrogen determination in welded metallic materials: Necessity and challenges
N2 - In the course of tomorrow's hydrogen-based energy transition, the construction of the corresponding infrastructure will play a central role. The majority of materials used to date are typically welded for component fabrication. In that context, steels are widely applied and can be prone to hydrogen embrittlement. For the evaluation of any hydrogen effect on, for example, the mechanical properties of a welded metallic material, the hydrogen content must be precisely determined. According to ISO 3690, carrier gas hot extraction (CGHE) can be used. In addition to the pure quantification of hydrogen, thermal desorption analysis (TDA) with varied heating rates can be used to determine and evaluate the bonding state at microstructural defects in the material. For both techniques, experimental and measurement influences have to be considered, which have a great effect on the result. For CGHE, for example, ISO 3690 suggests different sample geometries as well as minimum extraction times. The present study summarizes results and experiences of numerous investigations with different sample temperatures and geometries (ISO 3690 type B and cylindrical TDA samples) regarding: the influence of the sample surface (polished/welded), measurement accuracies depending on the sample volume. In particular, a deviating extraction temperature to the set temperature, can significantly falsify the measurement results. Based on the results, methods are shown to quickly reach the desired extraction temperature without having to physically interfere with the measurement equipment. This serves to substantially improve the reliability of hydrogen measurement through increased signal stability and accelerated hydrogen desorption. In general, an independent temperature measurement with dummy samples for the selected heating procedure is advisable to exclude possible unwanted temperature influences already before the measurement. In addition (and way more important), the methods described can be transferred directly to industrial applications.
T2 - Eurocorr 2023 - The European Corrosion Congress
CY - Brussels, Belgium
DA - 27.08.2023
KW - Hydrogen
KW - Carrier gas hot extraction
KW - Welding
KW - ISO 3690
KW - Measurement
PY - 2023
AN - OPUS4-58305
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
T1 - Schweißen im Betrieb an Wasserstoff-Ferngasleitungen
N2 - Wasserstoff gilt als Energieträger für die Erreichung der Klimaziele und einer nachhaltigen zukünftigen Energieversorgung. Für den notwendigen Transport des Wasserstoffs in großem Maßstab und über weite Entfernungen ist eine zuverlässige Pipeline-Infrastruktur erforderlich. Umfassende weltweite Forschungsprojekte deuten auf die allgemeine Kompatibilität der verwendeten überwiegend ferritischen Stähle für die vorgesehenen Betriebsbedingungen von bis zu 60 °C bei 100 bar Wasserstoff hin. Dies ist jedoch nicht direkt übertragbar auf schweißtechnische Reparatur- und Wartungsarbeiten an im Betrieb befindlichen Pipelines. Ein im Erdgasnetz etabliertes Verfahren stellt das „Hot-Tapping“ dar, bei dem eine unter Druck stehende Pipeline im Betrieb angebohrt wird. Hierfür kommt ein an die Rohrleitung geschweißtes Formstück zum Einsatz, das die Montage der Bohr-/Lochschneidemaschine ermöglicht. In den Richtlinien EIGA 121/14 bzw. AIGA 033/14 wird darauf hingewiesen, dass das Anbohren von Wasserstoffleitungen kein Routineverfahren darstellt: “[…] a hydrogen hot-tap shall not be considered a routine procedure […]“. Dieser Aussage liegt unter anderem zugrunde, dass das Anschweißen des Formstücks an das Rohr und alle zu erwartenden Wärmebehandlungen vor und nach dem Schweißen eine lokale Temperaturerhöhung verursachen. Insbesondere auch an der Rohrinnenfläche, die dem Wasserstoff ausgesetzt ist. Diese erhöhten Temperaturen begünstigen die Absorption und Diffusion von Wasserstoff in das Material. Besonders zu beachten ist außerdem die lokal auftretende kurzzeitige Austenitisierung des Materials, die eine lokal stark erhöhte Wasserstoffkonzentration verursachen kann. Aus den genannten Gründen gibt diese Studie einen kurzen Überblick über die derzeit weltweit verfügbaren Forschungsprojekte zum Schweißen von Wasserstoff-Pipelines im Betrieb. Vorgestellt werden unter anderem erste Ergebnisse des Kooperationsforschungsprojektes H2SuD, das derzeit an der BAM bearbeitet wird.
T2 - 6. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - Pipeline
KW - Schweißen
KW - Wasserstoff
PY - 2025
AN - OPUS4-62628
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Optimizing residual stresses in additively manufactured high-performance materials
N2 - The integration of modern high-performance materials in combination with additive manufacturing (AM) has revolutionized the approach to lightweight construction across diverse applications. This study explores the synergy between these materials and additive manufacturing (AM), focusing on their unique properties to engineer resource-efficient structures. Despite these advancements, machining these hard-to-cut materials such as iron-aluminide for safety-critical components remains challenging due to increased tool wear and compromised surface integrity. This research focuses on overcoming these challenges through the application of ultrasonic-assisted milling (USAM), a hybrid machining process exhibiting significant potential. By incorporating ultrasonic oscillations along the milling tool axis, USAM minimizes tool and component surface loads, enhancing tool life and producing defect-free, homogeneous surfaces with reduced roughness parameters. This investigation centers on the influence of ultrasonic-assisted milling on residual material stresses, crucial for component performance under load. In contrast to conventional milling generating tensile stresses, USAM induces advantageous compressive residual stresses, potentially enhancing the component's crack resistance. The study employs experimental variations in ultrasonic amplitude during the machining process to identify optimal parameters for achieving maximum compressive stresses. In addition, the depth profile of these residual stresses on the surface is investigated, which provides more detailed insights into their distribution and possible effects. This research not only contributes to the evolving environment of innovative manufacturing technologies, but also places particular focus on the central role of residual stresses in the performance and reliability of safety-critical AM components. The results not only contribute to a better understanding of ultrasonic-assisted milling, but also provide crucial guidance for the design of components that can withstand the challenges of real-world applications.
T2 - BMDK OvGU Magdeburg
CY - Magdeburg, Germany
DA - 19.06.2024
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - High-performance materials
KW - Surface integrity
KW - Residual stresses depth profile
PY - 2024
AN - OPUS4-62025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - "H2-SuD" Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2-Ferngasleitungen, Statusbericht – März 2024
N2 - Die Umstellung der Wirtschaft auf wasserstoffbasierte Energieversorgung soll in Deutschland vor allem auf Basis der Umstellung des bestehenden Erdgasnetzes erfolgen. Dabei sollen ca. 90 % dieser Fernleitungsnetze auf dem bestehenden Erdgasnetz basieren. Die Beimischung von Wasserstoff zum Erdgas als auch der reine Wasserstofftransport werfen jedoch die Frage auf, ob und wie kompatibel die eingesetzten Materialien sind. Die Reparatur- und Erweiterungsfähigkeit von Erdgas-Bestandspipelines ist zu klären, wenn diese auf Wasserstoff umgestellt werden. Denn gerade Gashochdruckleitungen müssen regelmäßig gewartet und erweitert werden, um einen ordnungsgemäßen Betrieb sicherzustellen. Insbesondere das Schweißen unter Betriebsdruck bzw. an in Betrieb befindlichen Gasleitungen ist eine der wichtigsten Instandhaltungstechnologien, unabhängig von der Zusammensetzung des geförderten Mediums. Es ist daher dringend notwendig, eine geeignete Teststrategie zu erarbeiten, welche die nötigen Vorrausetzungen für sicheres Schweißen an in Betrieb befindlichen Druckwasserstoffleitungen schafft und entsprechende Kriterien für die Praxis liefert. Im Projekt H2-SuD - Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2-Ferngasleitungen - soll geklärt werden, ob und wie stark mit einer Eigenschaftsdegradation geschweißter Rohrstähle in Gasnetzen in Folge einer Wasserstoffaufnahme zu rechnen ist. Die Präsentation gibt dazu einen kurzen Überblick über den aktuellen Status des Projektes. Die Förderung erfolgt im Rahmen der DVGW-Innovationsprogammes Wasserstoff (Nr. G 202131).
T2 - DVGW - Arbeitsgruppentreffen
CY - Berlin, Germany
DA - 19.03.2024
KW - Wasserstoff
KW - Pipeline
KW - Reparaturschweißen
KW - Betrieb
KW - Hochdruck
PY - 2024
AN - OPUS4-59758
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Stresses in repair welding of high-strength steels Part 2: Heat Control and Stress Optimization
N2 - In welding of high-strength steels, e.g., for foundations and erection structures of wind energy plants, unacceptable defects can occasionally be found in the weld area, which should be removed by thermal gouging and subsequent re-welding. High shrinkage restraint of repair welds may lead to crack formation and component failure, particularly in interaction with degraded microstructures and mechanical properties due to repair cycles. This study aims for elaboration of recommendations for repair concepts appropriate to the stresses and materials involved to avoid cold cracking, damage and expensive reworking. In part 1 [1] of this study systematic investigations of influences of shrinkage restraint on residual stresses and cold cracking risk during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures were focussed. In this part 2, the microstructure and residual stresses due to gouging and influences of heat control parameters in repair welding are analysed. A clear reduction in residual stress after gouging can be observed, especially for the specimens with restrained transverse shrinkage. Gouging to a depth of approx. 2/3 of the seam height does not lead to a complete relaxation of the observed reaction forces. Particularly for the higher strength steel S960QL, there are pronounced areas influenced by the gouging process in which a degradation of the microstructure and properties should be assumed. Overall, the repair welds show a significant increase in the width of the weld and HAZ compared to the original weld, especially in the case of S960QL/G89. The repair welds show higher welding-induced stresses than the original welds, especially in the areas of the HAZ and the base metal close to the weld seam. This behaviour can be attributed overall to increased restraint conditions due to the remaining root weld or shorter gouge grooves. In good agreement with earlier investigations, the residual stresses transverse to the weld can be significantly reduced by upwardly limited working or interpass temperatures and the reaction stresses resulting from high restraint conditions can be effectively counteracted. The influence of the heat input on the stress formation is low compared to the interpass temperature for both test materials.
T2 - IIW Annual Assembly 2023
CY - Singapore
DA - 16.07.2023
KW - Repair-welding
KW - High-strength steels
KW - Cold cracking
KW - Residual stresses
PY - 2023
AN - OPUS4-59254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Correlation of process, design and welding residual stresses in WAAM of high-strength steel components
N2 - High-strength fine-grained structural steels have great potential for modern weight optimized steel construc-tions. Efficient manufacturing and further weight savings are achievable due to Wire Arc Additive Manu-facturing (WAAM). First commercial high-strength welding consumables for WAAM are already available. However, the application is still severely limited due to a lack of knowledge and guidelines for the industry regarding welding residual stresses and component safety in manufacturing and operation. Residual stresses may be critical regarding the special microstructure of high-strength steels in context with the risk of cold cracking and component performance in service. Therefore, process- and material-related influences, as well as the design effects on residual stress formation and cold cracking, are being investi-gated in a research project (IGF 21162 BG) focusing a high-strength WAAM welding consumable with yield strength of over 800 MPa. Objectives are the establish-ment of special WAAM cold cracking tests and pro-cessing recommendations allowing economical, suita-ble, and crack-safe WAAM of high-strength steels. First studies on process-related influences showed transfor-mation residual stresses arising during cooling, which significantly influence stress evolution of the compo-nent during layer-wise build-up. This has not yet been investigated for WAAM of high-strength steels. Focus of this study is on the systematic investigation of interactions of the WAAM welding process and design with cooling time, hardness, and residual stresses.
Defined open hollow cuboids were welded and investi-gated under systematic variation (design of experi-ments, DoE) of the scale/dimensions (cf. Fig. 1a) and heat control (interlayer temperature Ti: 100–300 °C), heat input E: 200–650 kJ/m. The welding parameters were kept constant as possible to avoid any influence by the arc and the material transfer mode. The heat input adjusted primarily via the welding speed. The resulting different weald bead widths were considered by different build-up strategies (weld beads per layer) to ensure defined wall thicknesses. The hardness was determined on cross-sections taken from the manufac-tured hollow cuboids (Fig. 1c) and the analysis of the residual stress state was carried out by means of X-ray diffraction (XRD) at defined positions on the lateral wall (Fig. 1b).
The hardness is higher at the top compared to the lower weld beads, as shown in Fig. 1c exemplarily for central test parameters of the DoE = 425 kJ/mm, Ti = 200 °C). This may be attributed to the specific heat control of the top weld beads, i.e., quenching effects, which are not tempered by weld beads above as is the case for lower weld beads implying a higher hardness. It was observed that the hardness level decreases with increasing energy per unit length, while the in-terpass temperature has a rather low influence on the hardness
Residual stress analysis was performed on the lat-eral wall in the welding direction, cf. Fig. 1b, to deter-mine the influence of heat control and design. In the top area of the wall, maximum longitudinal residual stress-es of up to over 500 MPa exhibit, which corresponds to approx. 65% of the nominal yield strength of the mate-rial. The statistic evaluation of stress levels in welding direction of all test specimens show that adaption of heat input may reduce welding stresses up to 50%. In-terpass temperature has less pronounced effect on cool-ing times, microstructure, and on the residual level within parameter matrix. Overall, the results show a significant influence of heat input and component di-mensions on the residual stresses and minor effect of the interpass temperature. Hence, the properties of the specimens may be effectively adjusted via heat input. The working temperatures should be considered for global shrinkage behavior or restraints. Such investiga-tions of residual stress are necessary to further deter-mine local and global welding stresses regarding the consequences on the component safety during manu-facturing and service.
T2 - 6th International Symposium on Visualization in Joining & Welding Science through Advanced Measurements and Simulation
CY - Osaka, Japan
DA - 25.10.2022
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Kaltrisssicherheit
KW - Wärmeführung
KW - Windenergie
PY - 2022
AN - OPUS4-56725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Kurzvorstellung des DVGW-geförderten Projektes “H2SuD” - Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2-Gasleitungen
N2 - Die Wasserstoffinfrastruktur ist eine zentraler Bestandteil der erfolgreichen Umsetzung der wasserstoffbasierten Energiewende. Dabei bilden Ferngasleitungen quasi das "Rückgrat" der Transportinfrastruktur großer Gasmengen. Dabei müssen unter Umständen Reparaturen an den Pipelines durchgeführt werden. Dabei ist in der Erdgasinfrastruktur das Schweißen an in Betrieb befindlichen (d.h. von Gas durchflossenen) Pipelines Stand der Technik. Es ist jedoch vollkommen offen, inwieweit diese Technik auf die reine Wasserstoffpipelines übertragbar sind. Hierzu leistet das Projekt H2SuD wichtige Beiträge zur Aufklärung des Einfluss eines Reparaturschweißprozesses auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen.
T2 - Sitzung des Unterarbeitskreises / UAK 2.1.1 "Rohrleitungen" im Rahmen der Normungsroadmap Wasserstofftechnologien
CY - Online meeting
DA - 16.06.2023
KW - Wasserstoff
KW - Schweißen
KW - Pipeline
KW - Reparatur
KW - Prüfverfahren
PY - 2023
AN - OPUS4-57714
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - In situ Messung der chemischen Konzentration in der Schmelze während des WIG-Schweißens von Duplexstählen zur Analyse der Phasenverteilung
N2 - Die Kombination aus hoher Korrosionsbeständigkeit und guten mechanischen Eigenschaften von Duplexstählen (DSS) ist auf ihre chemische Zusammensetzung und das ausgewogene Phasenverhältnis von Ferrit (α) und Austenit (γ) zurückzuführen.
Viele industrielle Anwendungen erfordern eine stoffschlüssige Verbindung von DSS. Das Wolfram-Inertgas-Schweißen (WIG) ist relativ einfach zu handhaben, benötigt nur wenig Platz und ermöglicht ein automatisiertes Schweißen, mit sehr hoher Reproduzierbarkeit und ist daher hervorragend zum Schweißen von DSS.
Während der Erstarrung dieser Dualphasenstähle kann es zu kritischen Phasenverhältnissen von α und γ kommen, was zu Erstarrungsrissen, Korrosionsanfälligkeit, geringerer Duktilität und kritischen Festigkeitswerten führt. Um die gewünschten Werkstoffeigenschaften zu erhalten, muss daher die α/γ-Verteilung zuverlässig vorhergesagt werden. Dies geschieht in der Regel mit Hilfe des WRC1992-Diagramms. Die Vorhersagegenauigkeit des Ferritgehalts in diesem Diagramm ist jedoch meist nicht genau genug und muss daher optimiert werden. Daher ist es notwendig, selbst kleinste Veränderungen in der chemischen Zusammensetzung des Schweißguts idealerweise während des Schweißens zu überwachen. Dies wird in diesen Experimenten mit Hilfe der laser-induzierten Plasmaspektroskopie (LIBS) durchgeführt. Ein großer Vorteil dieser Technik ist die hochgenaue zeit- und ortsaufgelöste Messung der chemischen Zusammensetzung während des Schweißens. In vorherigen Arbeiten wurde bereits die chemische Zusammensetzung im Schweißgut und der WEZ quantifiziert. In der präsentierten Untersuchung wird der Einfluss einzelner Elemente, wie Nb und Cu, auf das resultierende Schweißmikrogefüge untersucht.
T2 - BMDK der Universität Magdeburg
CY - Magdeburg, Germany
DA - 25.01.2023
KW - LIBS
KW - In situ measurement
KW - WRC 1992 diagram
KW - Duplex stainless steel
KW - TIG welding
PY - 2023
AN - OPUS4-56902
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berkes, L.
A1 - Nehring, Grzegorz
A1 - Bonnerot, O.
A1 - Krutzsch, M.
A1 - Rabin, Ira
A1 - Richter, T. S.
T1 - Mixed Inks in Two Coptic Documents from the Hermopolite Region Relating to Lease Business
N2 - In this article, we present two Coptic papyri, P 11934 and P 11935 from the Berlin collection excavated in Ashmunein (ancient Hermopolis) by Otto Rubensohn in 1906. We employ a multi-disciplinary approach that takes into account both their materiality – writing support as well as ink – and their content, as has become ‘best practice’. 1 Material aspects of written documents have traditionally been the purview of papyrologists. Recently developed methods of scientific analysis generate sets of archaeometric data with the potential to improve understanding of the materiality of ancient document production, as well as to yield new evidence for genuine papyrological research questions. To achieve this, a large corpus of comparative data needs to be built. Our contribution offers a first step in this direction. We aim at presenting the papyri, which were selected because of the ink corrosion during conservation work at the Berlin collection, in a format that is exhaustive both for material and textual aspects. The inks from both papyri were analysed using a combination of techniques, contributing to our better understanding of the development of ink technology in Late Antiquity.
KW - Coptic papyri
KW - Methods of scientific analysis
KW - Sets of archaeometric data
KW - Mixed Inks
KW - Ink corrosion
KW - Ancient document production
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579948
DO - https://doi.org/10.48631/pylon.2023.3.98234
SN - 2751-4722
VL - 2023/3
IS - 3
SP - 1
EP - 18
PB - Ceative Commons Attribution ShareAlike
CY - Heidelberg, Germany
AN - OPUS4-57994
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghigo, Tea
A1 - Rabin, Ira
A1 - Buzi, P.
T1 - Black Egyptian inks in Late Antiquity: new insights on their manufacture and use
N2 - We present here our methodological approach applied to the study of Egyptian inks in Late Antiquity. It is based on an interdisciplinary strategy, bringing together a variety of disciplines from humanities and natural sciences, and it aims at systematically collecting a statistically relevant amount of data regarding the composition of the inks. The application of a wellestablished, non-invasive protocol that includes near-infrared imaging and X-ray fluorescence spectroscopy for in situ measurements enables the identification and characterisation of inks dating from the end of Late Antiquity onwards. However, sometimes this method limits our understanding when characterising more ancient inks. Trying to overcome these limitations, the potential of a new device for the characterisation of organic compounds is here explored by conducting preliminary tests on mock samples.
In this work, we present the results from 77 codicological units that include some of the earliest manuscripts of our corpus that presently lists 159 units.
KW - Ink
KW - Archaeometry
KW - Manuscripts
KW - Coptic
KW - Egypt
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503893
DO - https://doi.org/10.1007/s12520-019-00977-3
VL - 12
IS - 3
SP - 1
EP - 14
PB - Springer
AN - OPUS4-50389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Bonnerot, Olivier
A1 - Gordon, N.
A1 - Rabin, Ira
T1 - Writing and Correcting a Torah Scroll in Germany of the Thirteenth and Fourteenth Centuries
N2 - Scientific material analysis of the elemental composition of inks from different strata of a manuscript has the potential to complement scholarly observations using palaeography and philology in reconstructing the history of the manuscript’s production, correction and repair.
There are three typologically different classes of black writing inks: soot inks consist of carbon particles.
KW - Manuscript studies
KW - Hebrew studies
KW - Ink analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540658
DO - https://doi.org/10.25592/uhhfdm.9749
VL - Comparative Oriental Manuscript Studies Bulletin 7, 2021
IS - 7
SP - 2
EP - 20
PB - Centre for the study of manuscript cultures
CY - Hamburg
AN - OPUS4-54065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Girard, Solène
A1 - Rabin, Ira
T1 - Conservation and Technical Evaluation of an Early Medieval Papyrus Codex
N2 - In 2005, a team of Polish archaeologists discovered three Coptic codices, two on papyrus and one on parchment, in the rubbish dump of a hermitage at Sheik Abd el-Gurna, Egypt. While the parchment codex and the remains of the bindings of the papyrus ones have been conserved, the text blocks of the papyrus codices were opened and disassembled and after being disinfected remained untouched for nearly 15 years, until the current project started. Currently, all three books are stored in the collection of the Coptic Museum in Cairo. Our team undertook the conservation of and archaeometric research on the papyrus codices. The first of the books contains the Canons of Pseudo-Basil, while the second is an Encomium of St. Pisenthios. Both codices have been palaeographically dated to the seventh-eighth centuries CE. In this paper, we describe our project and present the results of the work carried out on the Canons of Pseudo-Basil. Our work involved photography in transmitted light, measurements of the thickness of the papyrus leaves, and digital microscopy under three-light illumination. These measurements allowed us to determine the types of the inks and characterize the papyrus writing substrate. For conservation, we used a novel method developed in the Egyptian Museum in Berlin that comprises suspending papyrus folios on a translucent, extremely thin Japanese paper inside glass frames without the use of adhesives.In 2005, a team of Polish archaeologists discovered three Coptic codices, two on papyrus and one on parchment, in the rubbish dump of a hermitage at Sheik Abd el-Gurna, Egypt. While the parchment codex and the remains of the bindings of the papyrus ones have been conserved, the text blocks of the papyrus codices were opened and disassembled and after being disinfected remained untouched for nearly 15 years, until the current project started. Currently, all three books are stored in the collection of the Coptic Museum in Cairo. Our team undertook the conservation of and archaeometric research on the papyrus codices. The first of the books contains the Canons of Pseudo-Basil, while the second is an Encomium of St. Pisenthios. Both codices have been palaeographically dated to the seventh-eighth centuries CE. In this paper, we describe our project and present the results of the work carried out on the Canons of Pseudo-Basil. Our work involved photography in transmitted light, measurements of the thickness of the papyrus leaves, and digital microscopy under three-light illumination. These measurements allowed us to determine the types of the inks and characterize the papyrus writing substrate. For conservation, we used a novel method developed in the Egyptian Museum in Berlin that comprises suspending papyrus folios on a translucent, extremely thin Japanese paper inside glass frames without the use of adhesives.
KW - Papyrus
KW - Codex
KW - Conservation
KW - Iron gall ink
KW - Coptic
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570998
DO - https://doi.org/10.1080/00393630.2023.2183554
SN - 0039-3630
SP - 1
EP - 12
PB - Taylor & Francis
AN - OPUS4-57099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Gordon, Nehemia
A1 - Rabin, Ira
T1 - Distinguishing between seemingly identical inks using scanning μXRF and heat maps
N2 - This study will present a new approach to distinguishing writing inks that have the same elemental compositions and visual appearances. The approach is based on displaying the intensity of elemental distributions as heat maps that represent data recorded with a scanning μX-ray fluorescence spectrometer. The heat maps present the data so as to facilitate digitally identifying and distinguishing between inks used to produce, correct, and reink two medieval Torah scrolls. As ritual objects, Torah scrolls had to be written in accordance with exacting standards that evolved over time. This requirement led to successive stages of modifications, sometimes over centuries. Both vitriolic and non-vitriolic inks used to modify Torah scrolls can be visually identical to each other. Furthermore, different non-vitriolic inks usually have an identical elemental composition. The solid material analysis evidence and its presentation as heat maps made it possible to discriminate between original and altered portions of text that in some cases would have been impossible. Our interdisciplinary work brought together conservation, material science, paleog-raphy, and philology to enable the identification of complex stratigraphy in multiple stages of production, correction, and reinking. ©2 0 2 2 Published by Elsevier Masson SAS.
KW - Spectroscopy
KW - Scanning micro-X-ray fluorescence
KW - Vitriolic iron-gall inks
KW - Non-vitriolic iron-gall inks
KW - Heat maps
KW - Torah scrolls
KW - Scribal corrections
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557271
DO - https://doi.org/10.1016/j.culher.2022.07.007
SN - 1296-2074
VL - 57
SP - 142
EP - 148
PB - Elsevier Masson SAS
AN - OPUS4-55727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Boaretto, E.
A1 - Newman, H.
A1 - Shevchuk, I.
A1 - Breterniz, S.
A1 - Rabin, Ira
T1 - Date, Materiality and Historical Significance of P.Köln Inv. 5941
N2 - The paper presents the results of the radiocarbon dating and ink analysis of a leather fragment bearing an important liturgical text in Hebrew from the early centuries of the common era. The work initiated by the scholarly interest in the text stresses the importance of the date and materiality of the manuscripts and closes with an appeal to the curators of manuscript collections.
KW - Mixed ink
KW - Radiocarbon
KW - Leather
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528063
DO - https://doi.org/10.25592/uhhfdm.8471
VL - 6/2
SP - 173
EP - 186
AN - OPUS4-52806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rabin, Ira
ED - Raggetti, L.
T1 - Material Studies of Historic Inks: Transition from Carbon to Iron-Gall Inks
N2 - This chapter offers observations and considerations concerning black writing inks encountered in writing supports transmitting documentary and literary texts of the late Antiquity and early Middle Ages. It discusses different types of inks, the Methods of their detection and their use in different times and geographical areas.
KW - Material analysis
KW - Writing inks
KW - Ink fingerprint
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528057
DO - https://doi.org/10.1163/9789004444805_006
SP - 70
EP - 78
PB - Brill
CY - Leiden
AN - OPUS4-52805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Eissel, A.
A1 - Treutler, K.
A1 - Wesling, V.
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die additive Fertigung (AM) durch schweißtechnische Verfahren eröffnet vielfach ökonomische Vorteile für eine ressour-ceneffiziente Bauteilherstellung. Gerade hinsichtlich der Homogenität und Anisotropie der resultierenden Schweißgefüge und den damit verbundenen Eigenschaften gibt es noch offene Fragestellungen. Die Einstellung der finalen Bauteilgeo-metrie und Oberflächengüte erfordert den komplementären Einsatz abtragender Fertigungsschritte. Hochleistungslegie-rungen auf der Basis von Nickel oder Kobalt sind aufgrund ihrer niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit schwer spanbar. Eine gezielte Gefügebeeinflussung mittels Modifikation der AM-Schweißzusatz-werkstoffe und der Einsatz des ultraschallunterstützten Fräsens (US) bietet das Potential insgesamt die Zerspanungssi-tuation zu verbessern. Dieser Lösungsansatz unter Gewährleistung des Erhalts der geforderten Werkstoff- bzw. Bauteileigenschaften ist Untersuchungsgegenstand eines Gemeinschaftsvorhabens (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF. Der vorliegende Beitrag stellt Ergebnisse für die beiden untersuchten FeNi- und CoCr-Legierungen sowie wesentliche Zusammenhänge zwischen Legierungsmodifikation, entstehender Gefügemorphologie und Zerspanungseigenschaften der mittels MAG additiv gefertigter Proben vor. Das größte Potential für die Modifikation zeigten Zr und Hf. Die Zulegierung in das Schweißgut erfolgte durch Beschichtung von Massivdrähten sowie durch Her-stellung von Fülldrähten.
T2 - DVS Congress - GST
CY - Essen, Germany
DA - 11.09.2023
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
PY - 2023
SN - 978-3-96144-230-0
VL - 389
SP - 697
EP - 703
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-58380
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
T1 - Materialverhalten und Herausforderungen beim Instandsetzungsschweißen von Altstahl
N2 - Neben dem Neubau von Stahlkonstruktionen ist aus Gründen der Nachhaltigkeit und Wirtschaftlichkeit in vielen Bereichen der stahlverarbeitenden Industrie aktuell ein deutlicher Trend zum Bauen im Bestand zu verzeichnen, um kostenintensive Sperrungen oder den Rückbau bestehender Konstruktion zu vermeiden. In Deutschland existieren mehr als 6000 Stahlbrücken und Stahlskelettbauten des Hochbaus aus Altstahl, die älter als 80 Jahre und in den nächsten Jahren instandzusetzen sind. Für werterhaltende und steigernde Maßnahmen an bestehenden Stahlkonstruktionen aus Altstahl, wie Instandsetzungen, Modernisierungen oder Umnutzungen findet das Schweißen als besonders wirtschaftliches Fügeverfahren bislang jedoch kaum Anwendung. Nieten- und Schraubenverbindungen sind dagegen oft äußerst unwirtschaftlich. Für die Instandsetzung ist vielfach bestehendes und beschädigtes durch neues Material zu ersetzen und mit Altstahl, meist Flussstahl, zu schweißen. Dieser Beitrag fokussiert die Analyse der Mikrostruktur in der Wärmeeinflusszone durch MSG-Schweißen verschiedener relevanter Altstähle, um die Schweißeignung durch ausgewählte Zusatzwerkstoffe zu beurteilen. Hierzu ließ sich mittels Dilatometrie subsidiär eine Datenbasis (ZTU-Diagramme, schweißsimulierte Gefüge) schaffen, um systematisch praxisrelevante Schweißexperimente mit minimalen Versuchs- und Materialaufwand abzuleiten.
T2 - Forschungsseminar Universität Magdeburg
CY - Magdeburg, Germany
DA - 08.01.2025
KW - Altstahl
KW - Schweiß-ZTU Diagramme
KW - Instandsetzungsschweißen
PY - 2025
AN - OPUS4-62406
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Repair welding of in service hydrogen pipelines
N2 - In the course of tomorrow's hydrogen-based energy transition, the construction of the corresponding infrastructure will play a central role. In that context, large diameter long-distance transmission pipelines for hydrogen will be the backbone in the European Union with service pressures from 70 to 90 bar (e.g., depending on national regulations). It is a major goal to rededicate the existing LNG infrastructure despite the necessity of new pipelines. From that point of view repairing of such transmissions pipelines via welding can be necessary. For the LNG infrastructure, it is state of the art that repair welding is conducted at pipelines under service, i.e., the LNG is still flowing as pressurized gas in the steel pipes. The reason is that a shut-down of large diameter pipelines is not so easy or sometimes impossible. In fact, as long no oxygen enters the pipeline, there would be any combustion or (in the worst case) explosion. At the moment, it is entirely open if current repair welding procedures for LNG pipelines can be transferred to pure hydrogen pipelines. In opposite to LNG, hydrogen can be way easier absorbed to the pipeline steels and diffuses through the material. If it accumulates in susceptible regions, i.e., in the welded joint, hydrogen assisted embrittlement could occur. The planned welding procedure requires a so-called preheating and maintenance of the weld joint of up to 300°C for several hours. This temperature is way higher compared to the typical service temperature of max. 40 to 50°C at operational pressures of 100 bar. In accordance to API 941, these low-alloyed pipeline steels are subjected to short-term service loads, which they are not designed for. For that reason, a collaborative project between BAM and DVGW (German Association for Gas and Water professions) was initiated in 2022 to answer the following questions by experiments and numerical simulation of: (1) How many hydrogen is additionally absorbed during the heating of the material to max. 300°C under remaining operational pressures? (2) Is the hydrogen concentration sufficient to reach a critical condition? (3) Which material and weld microstructure is the most susceptible? (4) Is there a significant difference in the repair welding behavior of LNG pipelines that had been already in use for long-term? (5) Which welding parameters and joint dimensions must be ensured for safe repair welding repair of typical pipelines? For that reason, the present study gives an overview on the current practice in repair welding of in-service pipelines, the industrial importance of this topic for the hydrogen-based energy transition and summarizes first results.
T2 - Eurocorr 2023 - The European Corrosion Congress
CY - Brussels, Belgium
DA - 27.08.2023
KW - Hydrogen
KW - Repair Welding
KW - Pipeline
KW - In-service
KW - High-pressure
PY - 2023
AN - OPUS4-58334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
A1 - Mente, Tobias
T1 - Zuverlässige Wasserstoff Bestimmung in Metallen und ihren Schweißverbindungen: Parameter, Einflüsse, Grenzen
N2 - Im Zuge der wasserstoffbasierten Energiewirtschaft von morgen, kommt der Errichtung der dementsprechenden Infrastruktur die zentrale Rolle zu. Der überwiegende Teil bisher eingesetzter und meist geschweißter Werkstoffe, wie Stähle, kann unter bestimmten Bedingungen zur Wasserstoffversprödung neigen. Dies umfasst die klassische verzögerte Kaltrissbildung während der Schweißverarbeitung als auch Versprödungsphänomene während des Betriebs. Für die Bewertung eines jeden Wasserstoffeffektes auf bspw. die mechanischen Eigenschaften eines geschweißten metallischen Werkstoffes, muss der Wasserstoffgehalt präzise bestimmt werden, Im Fall von Schweißnähten ist die beispielsweise nach der ISO 3690, die klassische isotherme Trägergas-Heißextraktion (TGHE). Die TGHE basiert dabei auf der beschleunigten Wasserstoffentgasung aufgrund der thermischen Aktivierung des Wasserstoffs bei erhöhten Temperaturen. Neben der reinen Quantifizierung des Wasserstoffs, kann über die thermische Desorptionsanalyse (TDA) mit variierten Heizraten, der Bindungszustand an mikrostrukturellen Defekten im Material festgestellt und bewertet werden. Für beide Techniken sind experimentelle und messtechnische Einflüsse zu beachten, die großen Effekt auf das Ergebnis haben. Für die TGHE schlägt die ISO 3690 schlägt beispielswiese verschiedene Probengeometrien sowie Mindestextraktionszeiten vor. Die vorliegende Studie fasst Ergebnisse und Erfahrungen zahlreicher Untersuchungen an der Bundesanstalt für Materialforschung und -prüfung (BAM) mit unterschiedlichen Probentemperaturen und Geometrien (ISO 3690 Typ B und zylindrische TDA-Proben) zusammen hinsichtlich: Einfluss der Probenoberfläche (poliert/geschweißt), Messgenauigkeiten in Abhängigkeit des Probenvolumens sowie die unzureichende Überwachung des Effektes des PI-Reglers auf die Extraktionstemperatur. Insbesondere eine abweichende Extraktionstemperatur zur eingestellten Temperatur, kann die Messergebnisse wesentlich verfälschen. Basierend auf den Ergebnissen werden Methoden aufgezeigt, um schnell die gewünschte Extraktionstemperatur zu erreichen, ohne physisch in das Messequipment eingreifen zu müssen. Dies dient der wesentlichen Verbesserung der Zuverlässigkeit der Wasserstoffmessung durch erhöhte Signalstabilität und beschleunigte Wasserstoffdesorption. Im Allgemeinen ist eine unabhängige Temperaturmessung mit Dummy-Proben für die gewählte Heizprozedur angeraten, um mögliche unerwünschte Temperatureinflüsse bereits vor der Messung auszuschließen. Die beschriebenen Methoden können ohne großen Aufwand direkt in die industrielle Anwendung überführt werden.
T2 - DVS Congress 2023
CY - Essen, Germany
DA - 11.09.2023
KW - Wasserstoff
KW - Schweißen
KW - Forschung
KW - ISO 3690
PY - 2023
SN - 978-3-96144-230-0
VL - 389
SP - 435
EP - 442
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-58309
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rabin, Ira
ED - Ciner, P.
ED - Nunez, A.
T1 - Writing Materials of the Dead See Scrolls
N2 - The first manuscripts from the Qumran caves were found in 1947. Within the following 10 years, clandestine and legal excavations revealed some 900 highly fragmented manuscripts from the late Second Temple period. This collection is generally known as Scrolls of the Judea Desert or Dead Sea Scrolls (DSS). For many years after their discovery, text analysis and fragmeents attribution were the main concern of the scholars dealing with the scrolls. The uncertain archaeological provenance of the larger part of the collection added an additional difficulty to the formidable task of sorting some 19000 fragments. After 60 years of scholar research the question of origin, archaeological provenance and correct attribution of the fragmenst are still hotly debated. To dtermine a possible contribution to the debate from the point of view of writing materials, we used otpical and electron microscopy, various X-ray based techniques as well as vibratiional sprectroscopy. We validated our approach with SY - based studies using the advantages of the synchroton radiation source with respect to the benchtop devices. Our laboratory studies showed that often production and storage locality could be distinguished thenks to the specific residues ("fingerprint") they left on the material. Moreover, we have diescovered that diferrent parchment production processses coexisted in the antiquity, and the resulting writing materials can readily be distinguished.
T2 - 2nd International Conference on Patristic Studies
CY - San Juan, Argentina
DA - 28.03.2017
KW - Dead Sea Scrolls
KW - Text analysis
KW - Fragmented manuscripts
KW - X-ray based techniques
KW - Archaeological provenance
PY - 2021
SN - 978-2-503-59149-0
DO - https://doi.org/10.1484/M.STR-EB.5.1211558
SN - 2566-073X
VL - 0095/ 19
SP - 325
EP - 331
PB - Brepols
CY - Turnhout, Belgium
AN - OPUS4-54593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Wasserstoffabhängige mechanische Eigenschaften der Schweißnahtgefüge niedriglegierter Stähle für Ferngasleitungen
N2 - Der Vortrag stellt aktuelle Ergebnisse des Fosta-Forschungsprojektes P1668 vor. Ziel ist hier, die Wasserstoffresistenz geschweißter Mikrostrukturen gängiger und neuer Pipeline-Stählen zu untersuchen. Im Fokus stehen hierbei durch physikalische Simulation nachgebildete, schweißnahtähnliche Mikrostrukturen in Form von (1) Wärmeeinflusszonen mit unterschiedlicher Abkühlgeschwindigkeit und (2) angelassene Zonen zur Simulation der typischen Mehrlagenschweißungen. Aus diesen repräsentativen Mikrostrukturen werden Zugproben extrahiert welche elektrochemisch oder mit Druckwasserstoff beladen werden. Aus diesen wird dann eine Datenbasis der spezifischen mechanische Eigenschaften unter Wasserstoff bereitgestellt. Die so entwickelte, praxisorientierte Prüfstrategie ermöglicht die schnelle und zuverlässige Bewertung sowohl in Betrieb befindlicher als auch neuer Rohrleitungswerkstoffe.
T2 - Herbstsitzung des DGM Arbeitskreises "Materialprüfung unter Wasserstoff"
CY - Dortmund, Germany
DA - 19.11.2024
KW - Wasserstoff
KW - Pipeline
KW - Mechanische Kennwerte
KW - Schweißen
KW - Prüfung
PY - 2024
AN - OPUS4-61750
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Standardization and examples for R & D activities on hydrogen technologies with respect to testing procedures in Germany
N2 - This contribution briefly summarizes the standardization activities in accordance with the "Nationale Roadmap Wasserstofftechnologien" and presents selected results on the activities in Germany with scope on hydrogen transport in pipelines. The talk was given during a panel discussion to set-up a steering committee for standardization for hydrogen pipelines and welding , coordinated by the International Institute of Welding.
T2 - IIW Annual Assembly, Meeting of Commission XI
CY - Singapore
DA - 19.07.2023
KW - Hydrogen
KW - Welding
KW - Pipelines
KW - Standardization
KW - Research
PY - 2023
AN - OPUS4-57976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hensel, J.
T1 - Influence of the WAAM process and design aspects on residual stresses in high-strength structural steels
N2 - High-strength fine-grain structural steels have great potential for weight optimization of many modern engineering structures. Efficient manufacturing can be achieved here above all by Wire Arc Additive Manufacturing (WAAM). First commercial high-strength welding consumables for WAAM are already available. However, due to a lack of knowledge and guidelines for the industry regarding welding residual stresses and component safety in manufacturing and operation, their application is still severely limited. Residual stresses play a crucial role here, as the sensitive microstructure of high-strength steels carries a high risk of cold cracking. For this reason, process- and material-related influences, as well as the design aspects on residual stress formation and the risk of cold cracking, are being investigated in a recent project (FOSTA-P1380/IGF21162BG). This high strength of the WAAM welding consumables is adjusted via a martensitic phase transformation. The volume expansion associated with martensite formation has a significant influence on residual stress evolution. However, this has not yet been investigated in relation to the processing of high-strength steels by WAAM. The aim of this work is to establish a WAAM cold crack test and easy-to-apply processing recommendations that will allow economical, expedient, and crack-resistant fabrication of high-strength steels, especially for SME. This paper focuses on the analysis of the effects of welding heat control and design of WAAM components on cooling conditions, microstructure, mechanical-technological properties and residual stresses. For this purpose, geometrically defined specimens (hollow cuboids) are welded fully automatically with a special, high-strength WAAM solid wire (yield strength >790 MPa). The heat control and specimen dimensions are varied within a statistical experimental design. The weld heat control is adjusted in such a way that the t8/5 cooling times are ensured within the recommended processing range (approx. 5–20 s). For this purpose, additional thermo-physical forming simulations using a dilatometer allowed the complex heat cycles to be reproduced and the resulting ultimate tensile strength of the weld metal to be determined. The WAAM welding of complex geometries with varying welding heat control and geometric factors or wall thicknesses not only has an effect on the cooling conditions, cooling times and microstructure, but also has a significant influence on the structural restraint conditions during welding. Hence, the welding experiments show significant effects of specimen scaling and heat input on the welding residual stresses, which may be detrimental regarding component properties and crack-critical tensile residual stresses. These complex interactions are analyzed within this investigation.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - WAAM
KW - Residual Stresses
KW - High-strength Steels
KW - Cold cracking safety
KW - Heat control
KW - Wind energy
PY - 2022
AN - OPUS4-56713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Intended weld repair of in service hydrogen pipelines
N2 - In the course of tomorrow's hydrogen-based energy transition, the construction of the corresponding infrastructure will play a central role. In that context, large diameter long-distance transmission pipelines for hydrogen will be the backbone in the European Union with service pressures from 70 to 90 bar (e.g., de-pending on national regulations). It is a major goal to repurposing the existing natural gas (NG) infrastructure despite the necessity of new pipelines. From that point of view repair welding or further welding of branch pipe etc. can be necessary during in-service, i.e., permanent flow of pressurized hydrogen. The reason is that a shut-down of large diameter pipelines is not easy or sometimes merely impossible. At the moment, it is entirely open if current repair welding procedures for NG pipe-lines can be transferred to pure hydrogen pipelines. For that reason, a collaborative project between BAM, DVGW (German Association for Gas and Water Professions) and a large number of gas grid operators, pipeline manufacturers and construction companies was initiated in 2023 to answer questions on: (1) How many hydrogen is additionally absorbed during the preheating and maintaining at interpass temperature under remaining operational pressures? (2) Is the hydrogen concentration sufficient to reach a critical condition? (3)Which material and weld microstructure are the most susceptible? (4) Is there a difference in the repair welding behavior of NG pipelines with materials in “used” condition? (5) Which welding parameters and joint dimensions must be ensured for safe repair welding? The final aim of this project is the publication of a recommended practice for repair welding of in-service hydrogen pipelines. For that reason, the present study gives an overview on: (A) current practice in repair welding of in-service pipelines and (b) plans for hydrogen pipelines and first results of international research projects.
T2 - IIW Annual Assembly, Meeting of Commission XI
CY - Singapore
DA - 19.07.2023
KW - Hydrogen
KW - Repair Welding
KW - Pipelines
KW - Research
PY - 2023
AN - OPUS4-57975
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Unter Druck gesetzt: Die unterschätzte Bedeutung des In-Service-Schweißen für die Wasserstoffinfrastruktur der Zukunft
N2 - Wasserstoff leistet als Energieträger der Zukunft einen entscheidenden Beitrag zur nachhaltigen Energieversorgung. Der Transport wird vorwiegend durch das europäische Ferngasleitungsnetz erfolgen. Bisherige Untersuchungen zeigen, dass bisher verwendete Rohrstähle grundsätzlich für den Wasserstofftransport geeignet sind. Diese Eignung ist nicht direkt auf Reparaturfragestellungen im Betrieb übertragbar, da Schweißungen aus technisch-ökonomischen Gründen oft unter fortwährendem Gasfluss durchgeführt werden. Ein im Erdgasnetz angewandtes Konzept ist das Anbohren druckführender Pipelines („Hot Tapping“). Dazu werden Zylinderhalbschalen zuerst durch Längs- und dann per Rohrrundnähten an die Pipeline geschweißt. Essenziell ist dabei die maßgeschneiderte Wärmeeinbringung, um das „Durchbrennen“ in die Pipeline zu vermeiden. Für zukünftige Wasserstoffpipelines liegt der Fokus u.a. auf dünnwandigen Leitungen. Im Gegensatz zu Erdgas, führen die beim Schweißen erreichten hohen Temperaturen an der Innenseite der Pipeline zu einer zusätzlichen Wasserstoffaufnahme in den Rohrstahl mit möglicher Materialdegradation. Zur praktischen Lösung der Fragestellung, sind internationale Aktivitäten im Gang. Diese umfassen bspw. die Möglichkeiten und Weiterentwicklung von realistischen Prüfkonzepten (u.a. durch maßstäbliche Bauteilversuche). Dazu untersucht die Bundesanstalt für Materialforschung und -prüfung (BAM) in einem DVGW-geförderten Kooperationsprojekt zusammen mit den grossen Gasnetzbetreibern, die Frage der Übertragbarkeit der Schweißkonzepte der Erdgastechnik auf zukünftiger Wasserstoffpipelines.
T2 - Herbstsitzung des DGM Arbeitskreises "Materialprüfung unter Wasserstoff"
CY - Dortmund, Germany
DA - 19.11.2024
KW - Wasserstoff
KW - Pipeline
KW - Reparaturschweißen
KW - Komponententest
PY - 2024
AN - OPUS4-61723
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Assessing ferrite content in duplex stainless steel weld metals: WRC '92 predictions vs. practical measurements
N2 - The weldability of stainless steels is largely controlled by the chemical composition, and alloys with ferritic or ferritic-austenitic solidification show the highest resistance to hot cracking. As the resulting phase balance also
affects the final properties, it may be beneficial to both foresee and measure the weld metal ferrite content. The WRC ’92 constitution diagram is currently the most accurate prediction tool available, but it does not take the cooling rate into consideration and the precision may be less accurate for stainless steels with high ferrite numbers (FN). This study aims to validate the reliability of the WRC ’92 diagram for weld metals with FN > 50. The chemical composition was altered through gas tungsten arc welding (GTAW) of UNS S32205 with ER347 filler wire that had been PVD-coated with either niobium (Nb), copper (Cu), nickel (Ni), manganese (Mn), carbon (C), or silicon (Si). The actual ferrite content was assessed using image analysis, FERITSCOPE® and X-ray diffraction (XRD). While the WRC ’92 diagram predictions were deemed accurate to acceptable for Ni, Si, and Mn, notable deviations were observed for Nb, Cu, and C. The FeriteScope exhibited a consistent trend with image analysis, though the values were higher, and scatter was wider, and the conversion factor is open for discussion. The lowest accuracy and largest spread were obtained using non-contact XRD, rendering it unsuitable for ferrite measurements of welds.
T2 - IIW Intermediate Meeting Comission IX-H
CY - Incheon, Republic of Korea
DA - 12.03.2024
KW - Duplex Stainless Steel
KW - Ferrite
KW - WRC 92
PY - 2024
AN - OPUS4-59750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Alloy modification for additive manufactured Ni alloy components Part I: Effect on microstructure and hardness
N2 - Alloy 36 (1.3912), also known as “Invar”, is an alloy with 36% nickel. The alloy has a remarkably low thermal expansion coefficient in certain temperature ranges. Therefore, it is used in applications in which dimensional stability is critical, such as moulding tools for composite materials in aerospace and automotive applications. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components. Additively manufactured components have a heterogeneous microstructure and anisotropic mechanical properties. In part I of this investigation, the initial alloy 36 is modified with the elements Ti, Zr and Hf up to a maximum of 0.33 wt.-%. The influence of the modification elements on the microstructure as well as on the hardness of the AM components is examined. Part II focusses on the effect of the alloy modifications on machinability as well as on the surface integrity of plasma-transferred-arc-welded (PTA) and finish milled invar components. The results show that PTA welding cause numerous finely distributed precipitates with high silicon content.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - Alloy modification
KW - Alloy 36
KW - Additive manufacturing
PY - 2022
AN - OPUS4-55439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
A1 - Schaupp, Thomas
ED - Brockmann, S.
ED - Krupp, U.
T1 - Wasserstoffunterstützte Kaltrissbildung in Schweißnähten hochfester Stahlgüten - Anforderungen an die Prüfung
N2 - Wasserstoff kann eine Rissbildung u.U. auch noch nach Tagen in der Schweißnaht bewirken. Dabei stellen höherfeste Stähle etablierte Kaltrissprüftests vor Herausforderungen. Generell nimmt die zur Rissvermeidung tolerierbare Wasserstoffkonzentration mit zunehmender Festigkeit der Werkstoffe ab. Zudem verändern weiterentwickelte Schweißverfahren die Nahtgeometrie und Wärmeeinbringung und die Ausbildung risskritischer Mikrostrukturen (z.B. Wärmeeinflusszone). Am Beispiel des Implant- und Tekken-Tests werden die Einsatz- u. Anwendungsgrenzen bewertet. Zu berücksichtigen ist, dass beim Schweißen eine äußere mechan. Beanspruchung durch bauteilspezifische Steifigkeitsverhältnisse wirksam ist. Zusätzlich werden weiterführende Prüfverfahren zur Bestimmung der Wasserstoffkonzentration und -diffusion in Schweißnähten vorgestellt, wie die Trägergasheißextraktion (TGHE) für die Ermittlung der Wasserstoffkonzentration (ISO 3690) oder Hochtemperaturdiffusionskoeffizienten.
Diese Werte sind für die schweißtechnische Praxis von großer Bedeutung, um Haltezeiten z.B. für das Wasserstoffarmglühen abzuleiten.
T2 - Tagung Werkstoffprüfung 2021
CY - Online meeting
DA - 02.12.2021
KW - Wasserstoff
KW - Kaltrissprüfung
KW - Schweißen
KW - Stahl
KW - Hochfest
PY - 2021
SN - 978-3-941269-98-9
SP - 15
EP - 20
PB - Stahlinstitut VDEh
CY - Düsseldorf
AN - OPUS4-53900
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Fertigungsbedingte Beanspruchungen und Kaltrisssicherheit in generativ gefertigten Bauteilen aus hochfesten Feinkornbaustählen
N2 - Der Vortrag gibt einen Überblick über den Einfluss der Prozessparameter auf die Eigenspannungen sowie die Härte in additiv gefertigten Bauteilen aus hochfestem stahl. Des Weiteren wird dargestellt, wie sich das Bauteildesign und trennende Fertigungsschritte auf die Eigenspannungen der Bauteile auswirken.
T2 - DVS Arbeitsgruppe (AG) V 12
CY - Online meeting
DA - 15.11.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
AN - OPUS4-59235
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - In situ measurement of chemical concentrations in the weld during TIG welding of Duplex stainless steels for phase distribution analysis
N2 - The combination of high corrosion resistance and good mechanical properties of duplex steels (DSS) is due to their chemical composition and the balanced phase ratio of ferrite (α) and austenite (γ).
Many industrial applications require a material joint of DSS. Tungsten inert gas (TIG) welding is relatively easy to use, requires little space and allows automated welding, with very high reproducibility and is therefore excellent for welding DSS.
During solidification of these steels, critical phase ratios of α and γ can occur, leading to solidification cracking, susceptibility to corrosion, lower ductility, and critical strength values. Therefore, to obtain the desired material properties, the α/γ distribution must be reliably predicted. This is usually done using the WRC1992 diagram. However, the prediction accuracy of the ferrite content in this diagram is usually not accurate enough and must therefore be optimized. It is therefore necessary to monitor even the smallest changes in the chemical composition of the weld metal, ideally during welding. This is done in these experiments using Laser-induced Breakdown Spectroscopy (LIBS). A major advantage of this technique is the highly accurate time- and spatially-resolved measurement of chemical composition during welding. Previous work has quantified the chemical composition in the weld metal and heat affected zone. In the presented study, the influence of individual elements, such as Nb and Cu, on the resulting weld microstructure is investigated.
T2 - IIW Intermediate Meeting 2023
CY - Hachenburg, Germany
DA - 27.02.2023
KW - LIBS
KW - Duplex Stainless Steel
KW - WRC 1992 diagram
KW - TIG welding
PY - 2023
AN - OPUS4-57079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Kannengießer, Thomas
A1 - Kromm, Arne
A1 - Dixneit, Jonny
A1 - Dilger, K.
A1 - Nitschke-Pagel, T.
A1 - Hensel, J.
A1 - Eslami, H.
T1 - Schwingfestigkeitsverbesserung hochfester Schweißverbindungen mit Hilfe neuartiger LTT-Zusatzwerkstoffe
N2 - Die Verwendung von LTT-Zusatzwerkstoffen stellt einen alternativen Ansatz zu den sonst üblichen Verfahren der Schweißnahtnachbehandlung zur Schwingfestigkeitserhöhung geschweißter Stahlkonstruktionen dar. Der wesentliche Wirkmechanismus beruht auf der Beeinflussung des Eigenspannungszustands durch die niedrige Martensitstarttemperatur bereits während des Schweißens. Dadurch werden die Druckeigenspannungen aus der behinderten Volumenausdehnung infolge Phasenumwandlung voll wirksam. Weiter weist die Schweißnaht eine hohe Härte auf, die die Schwingrissbildung verzögern kann, allerdings auch zu einer niedrigen Kerbschlagarbeit führt.
Im vorliegenden Forschungsvorhaben wurden grundlegende Untersuchungen zur schweißtechnischen Verarbeitung eines LTT-Zusatzwerkstoffes durchgeführt. Dies beinhaltet die Sicherstellung der Schweißbarkeit sowie die Charakterisierung der Verbindungseigenschaften.
Untersuchungen zur Schweißeignung machten deutlich, dass ein sicherer Einsatz in dem für hochfeste Stähle zur Verfügung stehenden Arbeitsfenster möglich ist. Der verwendete LTT-Zusatz auf Cr-Ni-Basis lässt sich mit hoher Nahtgüte fügen. Auch die mechanischen Eigenschaften erlauben den Einsatz im Bereich hochfester Stähle mit einer Streckgrenze von 960 MPa. Entwicklungspotential gibt es hinsichtlich der Zähigkeit. Die in dieser Arbeit erreichten Kerbschlagwerte liegen deutlich unter denen kommerziell verfügbarer konventioneller Schweißgüter. Die Untersuchungen belegen, dass der Effekt der martensitischen Phasenumwandlung im gesamten Schweißgut zum Tragen kommt. Die angestrebten hohen Druckeigenspannungen finden sich vornehmlich im Schweißgutinnern.
Im weiteren Vorgehen wurden Schwingfestigkeitsuntersuchungen an den Stählen S355J2 und S960Q unter Verwendung konventioneller Zusatzwerkstoffe im Vergleich zum LTT-Zusatz durchgeführt. Die verwendeten Konstruktionsdetails sind ein Stumpfstoß unter Variation der Schweißnahtausführung (DY-Naht und V-Naht), ein Kreuzstoß mit HV-Naht sowie ein Überlappstoß mit einseitig und beidseitig geschweißter Kehlnaht.
Weitergehend wurde eine bauteilähnliche Probe (die Längssteife) untersucht, bei der der LTT-Zusatzwerkstoff als zusätzliche Schweißlage aufgebracht wurde. Neben der Schwingfestigkeit wurden die Schweißnähte hinsichtlich der Eigenspannungen, der Eigenspannungsstabilität im Schwingversuch sowie metallografisch charakterisiert.
Eine generell positive Wirkung des LTT-Zusatzwerkstoffes im Hinblick auf die Schwingfestigkeitssteigerung kann nicht bestätigt werden. Teilweise ist eine Steigerung der Schwingfestigkeit bei Substitution konventioneller Zusatzwerkstoffe zu beobachten, teilweise zeigt sich kein Effekt. Ursächlich hierfür ist die bei manchen Stoßformen mangelnde Steifigkeit quer zur Schweißnaht, die zur Ausbildung hoher Druckeigenspannungen infolge Phasenumwandlung notwendig wäre. Die bauteilähnliche Längssteife bestätigt allerdings das grundlegende Potential der LTT-Zusatzwerkstoffe bei Vorliegen hinreichender Steifigkeit.
KW - Schweißen
KW - Eigenspannungen
KW - Schwingfestigkeit
KW - Hochfester Stahl
KW - LTT
PY - 2020
UR - https://matplus.shop/produkt/p-1060-schwingfestigkeitsverbesserung-hochfester-schweissverbindungen-mit-hilfe-neuartiger-ltt-zusatzwerkstoffe
SN - 978-3-946885-75-7
VL - P 1060
SP - 1
EP - 123
PB - Verlag und Vertriebsgesellschaft
CY - Düsseldorf
AN - OPUS4-51216
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Determination of residual stress evolution during repair welding of high-strength steel components
N2 - The sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of design and welding-induced residual stress can lead to crack formation and ultimately to component failure, particularly in interaction with the degradation of the microstructure and mechanical properties high-strength steels during the repair process.
In this context, component-related investigations of S500MLO and S960QL (FOSTA-P1311/IGF-Nr. 20162 N) focusing on welding residual stress evolution during local thermal gouging and rewelding. In this study, repair welding of S500MLO is carried out using in-situ digital image correlation (DIC) and ex-situ X-ray diffraction methods (XRD) to analyse strains and stresses. Therefore, self-restrained specimens were systematically gouged and rewelded with defined welding heat control (heat input, working temperature) and parameters. By means of structural mechanics calculations, geometries of self-restrained specimens were identified, that represent defined rigidity conditions of repair welds of real components. It could be shown that with increasing restraint intensity significantly higher residual stresses occur in the weld metal and heat affected zone. Furthermore, it revealed that the transverse stresses along the weld seam decrease at the weld seam ends leading to different stress state during gouging and welding. XRD analysis of the local residual stresses after cooling to RT longitudinal and transverse to the weld direction showed a good comparability with global DIC analyses.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - MAG-Schweißen
KW - Eigenspannungen
KW - Reparatur
KW - Thermisches Ausfugen
KW - Hochfester Stahl
PY - 2021
AN - OPUS4-56700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Berücksichtigung konstruktiver Einflüsse für die beanspruchungsgerechte Reparatur hochfester Schweißverbindungen
N2 - Bei der Montage von Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich. Die Verarbeitungsregelwerke empfehlen das lokale thermische Ausfugen betroffener Bereiche und erneutes Schweißen, geben aber aufgrund fehlender wissenschaftlich fundierter Untersuchungen kaum Informationen zu adäquaten Reparaturkonzepten. Dies betrifft insbesondere die Berücksichtigung und Optimierung resultierender schweißbedingter Beanspruchungen durch hohe Schrumpfbehinderungen der Ausfugenuten sowie der Gefügedegradation angrenzender Bereiche durch das Ausfugen und erneute Schweißen. Gerade bei hochfesten Stahlgüten ergeben sich dadurch häufig reduzierte mechanische Eigenschaften und zusätzliche schweißbedingte Beanspruchungen sowie erneut auftretende Nahtdefekte.
Deshalb sind für das Forschungsvorhaben systematische bauteilrelevante Untersuchungen der schweißbedingten Beanspruchungen und Gefügeveränderungen reparierter Schweißnähte in Abhängigkeit von der Schrumpfbehinderung und Wärmeführung beim Schweißen und Ausfugen sowie von der Reparaturzyklenanzahl geplant, mit dem Ziel Empfehlungen für beanspruchungs- und werkstoffgerechte Reparaturkonzepte abzuleiten. Hierfür sind gerade Analysen an hochfesten Stahlgüten S500 für den Offshore-Bereich und S960QL für den Mobilkranbau interessant, die zur Errichtung und Fertigung hocheffizienter Konstruktionen wie Windenergieanlagen notwendig sind. Die Erkenntnisse bieten eine Grundlage für entsprechende Normen und Regelwerke. Damit können letztlich Schäden und zumeist teure Nacharbeiten verhindert und eine verbesserte Ausnutzung des hohen Festigkeitspotentials hochfester Stähle erreicht werden. Gerade auch KMU können mit Blick auf die Kosten für Fertigung, Schweißarbeit und Material von den Erkenntnissen beim Einsatz hochfester Stähle, die für eine effiziente Realisierung der Energiewende in Deutschland notwendig sind, profitieren.
T2 - NA 092-00-05 GA (DVS AG Q 4/Q 4.1)
CY - Online meeting
DA - 10.03.2021
KW - Eigenspannungen
KW - Gefügedegradation
KW - Hochfester Feinkornbaustahl
KW - Reparatur
KW - Schweißen
KW - Wärmeführung
PY - 2021
AN - OPUS4-53316
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schaupp, Thomas
T1 - Einfluss von Konstruktion und Wasserstoff auf die Kaltrissbildung hochfester Feinkornbaustähle
N2 - Der konstruktive Leichtbau erfordert den zunehmenden Einsatz hochfester Feinkornbaustähle mit Streckgrenzen ≥ 690 MPa. Neben den durch die Wandstärkenreduzierung erreichbaren Einsparungen an Ressourcen und Fertigungszeit lässt sich eine weitere Minimierung der Schweißzeit und -kosten mittels abgesenkter Schweißnahtvolumina erreichen. Hierzu wurden moderne Lichtbogenprozesse, wie bspw. der modifizierte Sprühlichtbogen (Mod.SLB), mit erhöhter Abschmelzleistung entwickelt, mit denen auch enge Nahtspalte bzw. Nahtöffnungswinkel geschweißt werden können. Hochfeste Verbindungen unterliegen zunehmend erhöhten Anforderungen in Bezug auf die schweißtechnische Verarbeitung und der resultierenden Bauteilperformance und sicherheit. Dies gilt insbesondere beim Bauteil-schweißen mittels solcher Hochleistungsverfahren in Verbindung mit engen Nahtspalten. In der vorliegenden Arbeit soll dieser Herausforderung durch Klärung der Einflüsse auf die Kaltrissbildung bei einem hochfesten Feinkornbaustahl S960QL Rechnung getragen werden. Für die Kaltrissprüfung werden entsprechende adaptierte Proben analog dem selbstbeanspruchenden TEKKEN-Test verwendet und hinsichtlich Rissbildung, Gefüge, Gehalt an diffusiblem Wasserstoff und Eigenspannungen analysiert. Die Variation der Nahtöffnungswinkel der Prüfnähte erfolgt zwischen 30° und 60°. Zur Vermeidung wasserstoffunterstützter Kaltrissbildung wird die Wirksamkeit einer Nachwärmprozedur aus der Schweißwärme heraus untersucht. Als Ergebnis zeigen die Schweißgüter, die an reduziertem Nahtöffnungs-winkel erzeugt wurden, im Mittel etwas höhere Wasserstoffkonzentrationen. Zudem ist an diesen Schweißgütern eine vermehrte Mikro- als auch Makrorissbildung festzustellen. An allen Proben, die nicht nachgewärmt wurden, treten Kerbrisse aufgrund von Kaltrissbildung auf, deren Vermeidung sich durch ein Nachwärmen unmittelbar nach dem Schweißen als besonders effektiv darstellte.
T2 - DVS Congress - Große Schweißtechnische Tagung
CY - Online meeting
DA - 14.09.2020
KW - Hochfester Feinkornbaustahl
KW - MAG-Schweißen
KW - Kaltriss
KW - TEKKEN
PY - 2020
AN - OPUS4-51258
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hülagü, Deniz
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - de Préville, Sophie
A1 - Hoffmann, Johannes
A1 - Morán-Meza, José
A1 - Piquemal, Francois
A1 - Hertwig, Andreas
T1 - Characterization of electrical properties in microstructured ITO layers using spectroscopic ellipsometry
N2 - Thin indium tin oxide (ITO) layers are essential in optoelectronics due to their good electrical conductivity, optical transparency in the visible and near infrared regions, substrate adherence and chemical stability. They are widely used in photovoltaic cells, displays, and organic LEDs, and as low emissivity coatings in smart windows and energy-efficient buildings. For nanophotonic devices, understanding the interplay of ITO’s optical and electrical properties is crucial. Electrical resistivity can be tuned by modifying deposition conditions and layer thickness. However, measuring these properties, especially on microstructured surfaces, remains challenging due to the issues like homogeneity and instability during etching.
Spectroscopic ellipsometry (SE), a non-destructive and phase-sensitive optical technique, offers precise measurement of thin film thickness and dielectric properties. In this study, we investigated the layer thickness, optical constants, and sheet resistance of unstructured and microstructured ITO thin layers using SE. Unstructured layers were deposited via DC-magnetron sputtering on silicon (Si) substrates in argon (Ar) atmospheres with varying oxygen (O2) flows.
This multi-technique approach enhances the understanding of ITO layer structuring and provides robust methodologies for correlating optical and electrical properties, advancing metrology for nanotechnology applications and material science. It also opens the pathway to new reference samples and calibration methods for electrical properties involving device-like structured samples.
T2 - ICSE10 - 10th International Conference on Spectroscopic Ellipsometry
CY - Boulder, CO, USA
DA - 08.06.2025
KW - Ellipsometry
KW - Indium tin oxide (ITO)
KW - Scanning microwave microscopy (SMM)
KW - Sheet resistance calibration standards
KW - ITO wet etching
PY - 2025
AN - OPUS4-63631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Einfluss der Wärmeführung auf den Beanspruchungszustand in additiv gefertigten Bauteilen aus hochfestem Stahl
N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein.
T2 - OVGU-Kolloquium (BMDK des IWF)
CY - Magdeburg, Germany
DA - 23.06.2022
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Kaltrisssicherheit
KW - Wärmeführung
KW - Windenergie
PY - 2022
AN - OPUS4-56726
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Terhedebrügge, Gabriel
A1 - Prager, Jens
T1 - How can SHM be applied in a quality assured and legally compliant manner?
T1 - Wie kann SHM qualitätssicher und rechtssicher angewendet werden?
N2 - Many SHM applications developed at universities and research institutions have not yet left the laboratory scale. Possible reasons for this include:
- Real components and structures are often more complex than expected,
- The POD (probability of detection) of the SHM system is usually difficult to determine,
- The reliability of SHM systems is often unsatisfactory, and
- The transition from recurring inspection to permanent monitoring with automated SHM systems fails due to existing safety regulations and testing standards.
The workshop addresses these issues and aims to present solutions that facilitate the practical use of SHM. The solutions will be developed using real-world applications, such as those in the field of renewable energy.
N2 - Viele SHM-Anwendungen, die an den Universitäten und Forschungseinrichtungen entwickelt wurden, haben den Labormaßstab noch nicht verlassen. Mögliche Gründe dafür sind,
- dass reale Bauteile und Strukturen häufig komplexer sind als erwartet,
- die POD (probability of detection) des SHM-Systems zumeist schwer bestimmbar ist,
- die Zuverlässigkeit der SHM-Systeme oft nicht zufriedenstellend ist und
- der Übergang von wiederkehrender Prüfung zur permanenter Überwachung mit automatisierten SHM-Systemen an vorhandenen Sicherheitsrichtlinien und Prüfvorschriften scheitert.
Der Workshop greift diese Fragestellungen auf und soll Lösungsansätze aufzeigen, die den Einsatz von SHM in der Praxis erleichtern. Die Lösungen werden beispielhaft für reale Anwendungen, z.B. aus dem Bereich der erneuerbaren Energien, erarbeitet.
T2 - SCHALL 25
CY - Dresden, Germany
DA - 28.03.2025
KW - SHM
KW - Legal aspects
KW - Pressure vessels
KW - SMART-tools
KW - QI-Digital
KW - Periodic inspection
PY - 2025
AN - OPUS4-62909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Large scale hydrogen assisted cracking test for thick walled SAW joints for offshore applications
N2 - Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods or jackets. These components are typically submerged arc welded (SAW) high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicate the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam / layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled with 22 passes and a seam length of 1,000 mm. Additional welded stiffeners simu-lated the effect of a high restraint, to stimulate critical HAC conditions. The necessity of a minimum waiting time (MWT) before the NDT can be conducted (to exclude HAC) was critically verified by the application of ultrasonic testing of the welded joint at different time-steps of the NDT of 48 h after welding. The residual stresses were determined by a robot XRD goniometer. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modelling allowed the qualitative estimation of the hydrogen diffusion in the weld. A remarkable HAC occurrence was not identified and proves both, a certain resistance of the weld joint to HAC and the (questionable) duration of the MWT.
T2 - IIW Annual Assembly, Meeting of Commission II-C
CY - Singapore
DA - 19.07.2023
KW - Mock-up
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - Offshore
KW - Steel
PY - 2023
AN - OPUS4-57977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Adequate repair concepts for high-strength steel weld joints for offshore support structures considering design influences
N2 - The sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of global and local welding-induced stresses may lead to crack formation and component failure, particularly in interaction with the degradation of the microstructure and mechanical properties of high-strength steels during the repair process [1]. Corresponding standards hardly provide any information on adequate repair concepts, and there is no uniform scientific data on which to base such concepts.
In this study, several relevant findings are discussed based on examples of structural engineering focusing on mechanical-technological properties and residual stresses, e.g. [1]. Further experimental and numerical work as conducted by [2] and weld tests under defined restraint conditions in special weld test-setups [3] show that an optimization of the welding-induced stresses of high-strength structural steels is achievable by means of an adapted heat control. The present research involves systematic investigations of influences of shrinkage restraint, the number of repair cycles and heat control during repair welding of a recently available high-strength offshore steel S500MLO (EN 10225-1). A quantification of the shrinkage restraint of repair weld joints is achievable by means of restraint intensity concept [4], analogous to previous studies [5]. Using structural mechanics calculations, geometries of self-restrained specimens are identified representing different defined rigidity conditions of repair welds considering actual high-strength steel components. Welding experiments with DIC analyses (digital image correlation) of the occurring strains during welding and XRD analyses (X-ray diffraction) of the resulting residual stresses after welding and cooling show increasing transient loads and significantly elevated residual stress profiles in the weld area with increasing restraint intensity. Especially in the heat affected zone, tensile residual stresses of up to 80 % of the nominal yield strength occur when welding under increased restraint conditions. In relation to the presented existing results, this indicates that a safe repair welding is primarily achievable by means of appropriate repair concepts and heat control taking into account the high welding stresses and special microstructures of high-strength steels. Finally, the aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines, especially for SMEs, in order to avoid damage and, in most cases, expensive reworking and to improve the full utilization of the potential of high-strength steels.
T2 - 74th IIW Annual Assembly and International Conference, C II-A
CY - Online meeting
DA - 07.07.2021
KW - High-strength structural steels
KW - Welding
KW - Repair
KW - Residual stresses
KW - Restraint
PY - 2021
AN - OPUS4-53320
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique authenticator for additively manufactured parts derived from 3D microstructural information
N2 - Additive manufacturing (AM) is rapidly emerging from rapid prototyping to industrial production [1]. Thus, providing AM parts with a tagging feature that allows identification, like a fingerprint, can be crucial for logistics, certification, and anti-counterfeiting purposes since nearly any geometry can be produced by AM with stolen data or reverse engineering of an original product. However, the mechanical and functional properties of the replicated part may not be identical to the original ones and pose a safety risk [2].
Several methods are already available, which range from encasing a detector to leveraging the stochastic defects of AM parts for the identification, authentication, and traceability of AM components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface of the internal cavity of hollow components. Local manipulation of components may alter the properties. The external tagging features can be altered or even removed by post-processing treatments. Integrating electronic systems [4] in AM parts can be used to identify and authenticate components with complex or customized geometries. However, metal-based AM, especially in powder bed fusion (PBF-LB/M) techniques, has a strong shielding effect that interferes with the communication between the reader and the transponder.
Our work suggests a methodology for the identification, authentication, and traceability of AM components using microstructural features in AM components. We will show a workflow that includes analysing 3D micro computed tomography data and selecting a set number of voids that fulfil the identification criteria. We will show the results this workflow produces for a series of 20 Al-based cuboid samples with identical processing parameters and discuss their prospects and limitations. The workflow can help to establish a non-tamperable connection between an additively manufactured part and its digital data and hence link the physical and the digital world.
T2 - MSE Konferenz
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Additive Manufacturing
KW - Fingerprint
KW - Computed tomography
PY - 2024
AN - OPUS4-62288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - H2Mare - PtX-Wind: UAP 5.4 BAM Offshore Corrosion - Seawater Laboratory
N2 - The lecture will focus on the experimental possibilities in BAM's seawater laboratory at the Eidersperrwerk. In this laboratory, water parameters can be monitored and, for the first time, it is possible to colonise and maintain salt water growth in a corrosion laboratory environment in order to study systems and materials for offshore applications.
T2 - Leitprojekt H2Mare Verbundtreffen PtX-Wind & TransferWind
CY - Frankfurt am Main, Germany
DA - 05.12.2024
KW - Offshore Corrosion
KW - Marine Corrosion
KW - Corrosion
KW - Green Hydrogen
PY - 2024
AN - OPUS4-62055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - Das Meerwasserlabor am Eidersperrwerk
N2 - Das Meerwasserlabor (Laborcontainer) ist eine Remote-fähiges Elektrochemie-Labor mit entfeuchtungsfähiger Klimatisierung in dem eine Vielfalt an experimentellen Möglichkeiten besteht. Das Alleinstellungsmerkmal ist der Meerwasser-Bypass, durch den eine Besiedlung und Erhalt von Salzwasser- bzw. Brackwasserbewuchs (Bakterien, Algen, Tiere, Pilze, etc.) möglich ist. Der jährliche Verlauf der Meeresumwelt wird dadurch abgebildet.
T2 - Leitprojekt H2Mare Verbundtreffen PtX-Wind & TransferWind
CY - Frankfurt am Main, Germany
DA - 05.12.2024
KW - Offshore Corrosion
KW - Marine Corrosion
KW - Corrosion
KW - Green Hydrogen
PY - 2024
AN - OPUS4-62054
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Erxleben, Kjell
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Michael, Thomas
A1 - Börner, Andreas
T1 - Microstructure characterization of dissimilar metal welds of innovative high- and medium-entropy alloys to austenitic stainless steels joint by tungsten inert gas and friction stir welding
N2 - The new multi-element alloying concept of systems with defined entropy (HEA — high-entropy alloy or MEA — medium-entropy alloy) is increasing in material research interest. Improved properties or combinations of properties are shown by several systems. Thus, the resulting microstructures and production of HEA/MEA as well as properties have been primarily investigated so far. Furthermore, processing is a key issue to transfer HEA/MEA systems to real components. Since welding is the most important joining process for metals, it is crucial to investigate the influence of welding to guarantee component integrity. Since most HEA are made of expensive alloying elements such as Co or Ni, they will not be used entirely as structural materials. Thus, it can be advantageous to weld conventional alloys such as austenitic stainless steels with the HEA and MEA to produce components that are both application-oriented and economically viable. Therefore, in this paper, first results of dissimilar metal welding, by tungsten inert gas (TIG) and friction stir welding (FSW), of a CoCrFeMnNi HEA as well as a CoCrNi MEA with a conventional AISI 304 austenitic stainless steel are presented. The focus is on the microstructure formation due to the two welding processes. The results of TIG welding show a dendritic microstructure, whereas in FSW both materials are stirred but still coexist.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2023
DO - https://doi.org/10.1007/s40194-023-01618-z
SN - 1878-6669
SP - 1
EP - 9
PB - Springer
AN - OPUS4-59252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Effect of Ultrasonic-Assisted Machining for Surface Functionalization of Innovative Work-Hardening Multi-Principal-Element Alloys
N2 - Multi-principal-element alloys (MPEAs) are an alloying concept consisting of at least two main alloying elements resulting in unique microstructures and potentially superior physical, mechanical and chemical properties, for instance a high work hardening capacity. These characteristics are determined by four core effects: sluggish diffusion, severe lattice distortion, high-entropy and cocktail effect. The development of MPEAs is a promising approach to extend the range of applications of conventional alloys by exploiting these core effects. In the present study, as reference to the conventional high-manganese steel X120Mn12 (ASTM A128), characterized by particularly high work hardening capacity generating exceptional mechanical properties, work-hardening MPEAs based on the equimolar composition CoFeNi in combination with Mn and C were developed. Specimens were produced as bulk material by melting via an electric arc furnace. In a second step the specimens undergo a surface finishing via milling process. Therefore, a hybrid milling process was used which, in addition to producing defined surfaces, also has the potential to reduce tool wear and increase surface integrity by introducing compressive stresses and increasing hardness through pronounced work hardening in comparison to conventional machining. The so-called ultrasonic-assisted milling (USAM) is characterized by an axial oscillation of the tool during the milling process. The machining parameters were varied to analyze the effect on work hardening together with process forces during milling and resulting surface integrity. Subsequently, microstructure evolution, hardness as well as resulting wear resisting capacity were investigated and correlated with the composition and the USAM parameters. For the MPEA CoFeNi-Mn12C1.2 a pronounced lattice strain and grain refinement due to the plastic deformation during the USAM was recorded, especially at high USAM amplitude and lower cutting speed due to the greater number of tool oscillations per cutting engagement. Consequently, a hardness increase of up to 380 HV0.025 was induced for the aforementioned MPEA exhibiting a higher wear resistance compared to the X120Mn12. This shows the promising approach for the development of work-hardening materials based on new alloy concepts such as MPEAs allowing also coatings required for applications in tribological systems. As conventional hard and wear-resistant coatings are challenging in machining due to massive tool wear this approach of functional coating materials with high hardening capacity during USAM have the potential to reduce tool wear and ensure a adequate surface integrity and wear resistance.
T2 - 50th International Conference on Metallurgical Coatings and Thin Films (ICMCTF 2024)
CY - San Diego, CA, USA
DA - 19.05.2024
KW - Ultrasonic assisted milling
KW - Surface integrity
KW - High entropy alloys
PY - 2024
AN - OPUS4-61928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulte, Petra
T1 - Physikalische Gefahren: Einstufungskriterien, Prüfmethoden, Vergleich mit Gefahrgutvorschriften
N2 - Vorgehensweise und Verfahren für die Validierung von Informationen zur Bewertung der Eigenschaften von Stoffen und Gemischen, die zu einer Einstufung und Kennzeichnung der physikalischen Gefahren nach der CLP-Verordnung (Verordnung (EG) Nr. 1272/2008) führen.
T2 - Haus der Technik: GHS/CLP Basisseminar - Einstufen und Kennzeichnen mit dem GHS (CLP-Verordnung)
CY - Online meeting
DA - 01.06.2021
KW - Einstufung
KW - Kennzeichnung
KW - GHS
KW - CLP
KW - Prüfmethoden
KW - Gefahrenklasse
KW - Gefahreneigenschaften
PY - 2021
AN - OPUS4-53184
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulte, Petra
T1 - Physical hazard testing and assessment strategies
N2 - The presentation will give an overview of the testing required for physical hazards under the BPR and CLP Regulations (Regulation (EU) No 528/2012 and Regulation (EC) No 1272/2008), safety characteristics, actual Standards and the UN Manual of Tests and Criteria as well, the importance of quality assurance in testing and data reporting, and the testing and assessment strategies on topics that have been specifically asked by EU Member States.
T2 - Biocides Working Group Meeting I-2021, Training on physical hazards for ECHA Working Group – Analytical methods and Physico-Chemical Properties (APCP) to the Biocidal Products Committee
CY - Online meeting
DA - 16.03.2021
KW - Biocidal Products Regulation
KW - Data requirements
KW - Screening tests
KW - Data waiving
KW - Hazard classification
KW - Physical hazard classes
KW - ECHA
KW - Competent Authority
KW - Applications for Union authorisation of biocidal products
PY - 2021
AN - OPUS4-52397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fayet, G.
T1 - First models to predict thermal decomposition properties of possible self-reactive substances based on industrial datasets
N2 - Self-reactive substances are unstable chemical substances which can easily decompose and may lead to explosion. For this reason, their thermal stability properties are required within regulatory frameworks related to chemicals in order to assess their hazardous properties. Due to the fast development and availability of computers, predictive approaches like QSPR models are increasingly used in the evaluation process of hazardous substances complementary to experiments.
In that context, the HAZPRED project (2015-2018) aimed to develop QSPR models to predict physical hazards of substances to fill the lack of knowledge on these hazardous substances quickly.
An experimental campaign, based on 50 samples provided by Industrial producers, was carried out on potential self-reactive substances, for which no QSPR model already existed. Their heats of decomposition were characterized using differential scanning calorimetry in homogeneous experimental conditions.
QSPR models were derived using the GA-MLR method (using a genetic algorithm and multi-linear regressions) using molecular descriptors calculated by Dragon software based on both 3D molecular structures from density functional theory (DFT) optimizations, to access three-dimensional descriptors, and SMILES codes, favoring the access to simpler models, requiring no preliminary quantum chemical calculations. All models respected the OECD validation guidelines for regulatory acceptability of QSPR models. They were tested by internal and external validation tests and their applicability domains were defined and analyzed.
If improved models should be expected with larger database (and a better ratio between size and chemical diversity), these first models already represent a screening tool capable to access early reactive hazards.
T2 - 19th International Workshop on Quantitative Structure-Activity Relationships in Environmental and Health Sciences
CY - Online meeting
DA - 07.06.2021
KW - QSPR
KW - Self-reactive substances
KW - Thermal decomposition
PY - 2021
AN - OPUS4-53178
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Entwicklung innovativer Niobcarbid-Fräswerkzeuge
N2 - Die Niobvorkommen übersteigen die von Wolfram um ein Vielfaches. Mit 92 % ist Brasilien heute der weltweit größte Niobproduzent. Daher ist NbC eine nachhaltige und wirtschaftliche Alternative zu konventionellen Schneidstoffen, insbesondere zu Wolframkarbid (WC). Darüber hinaus kann NbC in einer Ni-Legierungsmatrix verwendet werden und bietet somit als Ersatz für WC in einer Co-Matrix als Schneidstoff erhebliche Vorteile in Bezug auf Gesundheitsrisiken sowie Rohstoffpreis- und Versorgungsrisiken. Auf der Grundlage jüngster Studien, in denen eine höhere Leistung von NbC im Vergleich zu WC-Schneidwerkzeugen festgestellt wurde, ist in dieser Studie die Zusammensetzung NbC-12Ni-4Mo-4VC für die Fertigbearbeitung eines hochfesten Stahls S960QL gewählt worden. Die Versuche wurden auf einer ultraschallunterstützten 5-Achsen-Fräsmaschine mit speziell angefertigten NbC-Werkzeugen durchgeführt, um sie mit handelsüblichen beschichteten WC-Schneideinsätzen zu vergleichen. Darüber hinaus wird der Einfluss eines Beschichtungssystems für die NbC-Schneidplatten getestet und hinsichtlich seiner Leistung im Zerspanungsprozess bewertet. Werkzeugverschleiß- und Schnittkraftanalysen werden durchgeführt, um optimale Parameterkonstellationen und Werkzeugeigenschaften für das neue NbC-Werkzeug zu ermitteln. Zusammen mit der Oszillation des ultraschallunterstützten Fräsens können die Belastungen auf die Bauteiloberfläche und das Werkzeug reduziert und das Verschleißverhalten des neuartigen NbC-Werkzeugs verfeinert werden. Diese Fräsversuche werden von standardisierten Verschleißtests mit den oben genannten Materialkombinationen begleitet und die Ergebnisse miteinander korreliert. Schließlich wird auch das Verhalten beim Einsatz schwer zerspanbarer Werkstoffe wie Ni-Legierungen oder innovativer Materialien wie Eisenaluminid getestet. Mit dieser Strategie lassen sich umfassende Erkenntnisse für den zukünftigen effizienten Einsatz von NbC für Fräswerkzeuge erzielen, die bereits seit Jahrzehnten in Form von WC erforscht werden.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium der Otto-von-Guericke Universität Magdeburg
CY - Magdeburg, Deutschland
DA - 30.11.2022
KW - Niobcarbid
KW - Zerspanungswerkzeug
KW - Ultraschallunterstütztes Fräsen
KW - Werkzeugverschleiß
PY - 2022
AN - OPUS4-56632
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schaupp, Thomas
T1 - Zur Bewertung der Kaltrissempfindlichkeit moderner hochfester Feinkornbaustähle mit dem Implant-Test
N2 - Der Implant-Test nach ISO 17642-3 gehört zur Gruppe der fremdbeanspruchten Kaltrisstests, bei dem eine äußere Beanspruchung auf einen zylindrischen Stab (Implant-Probe) definiert aufgebracht wird. Mit dieser Kaltrissprüfung wurden vergleichende Analysen zur Kaltrissempfindlichkeit der modernen hochfesten Feinkornbaustähle S960MC und S960QL durchgeführt. Zudem kamen sowohl Massiv- als auch Metallpulverfülldraht zur Variation der Wasserstoffkonzentration zum Einsatz. Der Einsatz des modernen modifizierten Sprühlichtbogens ermöglichte außerdem die Untersuchung des Einbrandprofils auf die Kaltrissbildung.
T2 - Sitzung des NA 092-00-05 GA „Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)“
CY - Hamm, Germany
DA - 04.03.2020
KW - Hochfester Feinkornbaustahl
KW - MAG-Schweißen
KW - Wasserstoff
KW - Kaltriss
KW - Implant-Test
PY - 2020
AN - OPUS4-50506
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Einfluss der Schweiß- und Prüfparameter bei der Heißrissbewertung hochfester Schweißzusatzwerkstoffe
N2 - Die Heißrissneigung beim Schweißen kann mittels einer ganzen Reihe von Prüfverfahren ermittelt werden. Eine etablierte Methode ist die sogenannte Varestraint-Prüfung, welche auch an der Bundesanstalt für Materialforschung und -prüfung (BAM) als modifizierter Varestraint/Transvarestraint-Test (MVT) zum Einsatz kommt. Die Ergebnisse von Varestraint-Prüfungen hängen jedoch stets in unterschiedlichem Maße von der individuellen Prüfmaschinenauslegung und den verwendeten Prüfparametern ab. Dies kann zu einer uneinheitlichen Bewertung des Rissverhaltens führen, wenn die Risslänge konventionell als Kriterium für die Rissneigung herangezogen wird. Scheinbare Abhängigkeiten von Prozessparametern erschweren dann die Interpretation der Ergebnisse. Eine neuartige Bewertungsmethodik entkoppelt den Maschineneinfluss vom Materialverhalten und verwendet die Dehnrate als Risskriterium in Analogie zu Prokhorovs Heißrissmodell. Die neue Auswertung wird anhand einer Studie hochfester Schweißzusatzwerkstoffe vorgestellt, deren Rissverhalten in Abhängigkeit der chemischen Zusammensetzung und der Schweißparameter bewertet wird.
T2 - 5. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 23.02.2023
KW - Heißrisse
KW - Varestraint-Test
KW - Materialprüfung
PY - 2023
AN - OPUS4-57070
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Kannengießer, Thomas
A1 - Kromm, Arne
A1 - Hensel, J.
T1 - Influence of the WAAM process and design aspects on residual stresses in high-strength structural steels
N2 - Wire arc additive manufacturing (WAAM) enables the efficient production of weight-optimized modern engineering structures. Further increases in efficiency can be achieved by using high-strength structural steels. Commercial welding consumables for WAAM are already available on the market. Lack of knowledge and guidelines regarding welding residual stress and component safety during production and operation leads to severely limited use for industry applications. The sensitive microstructure of high-strength steels carries a high risk of cold cracking; therefore, residual stresses play a crucial role. For this reason, the influences of the material, the WAAM process, and the design on the formation of residual stresses and the risk of cold cracking are being investigated. The material used has a yield strength of over 800 MPa. This strength is adjusted via solid solution strengthening and a martensitic phase transformation. The volume expansion associated with martensite formation has a significant influence on the residual stresses. The focus of the present investigation is on the additive welding parameters and component design on their influence on hardness and residual stresses, which are analyzed by means of X-ray diffraction (XRD). Reference specimens (hollow cuboids) are welded fully automated with a systematic variation of heat control and design. Welding parameters and AM geometry are correlated with the resulting microstructure, hardness, and residual stress state. Increased heat input leads to lower tensile residual stresses which causes unfavorable microstructure and mechanical properties. The component design affects heat dissipation conditions and the intensity of restraint during welding and has a significant influence on the residual stress.
KW - DED-arc
KW - Additive manufacturing
KW - High-strength steel filler metal
KW - Residual stress
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572698
DO - https://doi.org/10.1007/s40194-023-01503-9
SN - 1878-6669
VL - 67
IS - 4
SP - 987
EP - 996
PB - Springer
CY - Berlin
AN - OPUS4-57269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
T1 - Prozessüberwachung in der additiven Fertigung von Metallen - das Projekt ProMoAM
N2 - Prozessüberwachung in der additiven Fertigung von Metallen - das Projekt ProMoAM. In diesem Vortrag wird das gesamte Projekt vorgestellt. Dabei wird auf die Thermografie im LMD und L-PBF Prozess näher eingegangen. Hierbei werden sowohl stationäre als auch mit bewegte Systeme vorgestellt.
T2 - Webinar: Inline-Messtechnik und –Prozessüberwachung
CY - Online meeting
DA - 01.07.2020
KW - Pulverbettverfahren
KW - Laser Metal Deposition
KW - Thermografie
KW - Optische Tomografie
PY - 2020
UR - https://quality-engineering.industrie.de/webinarreihe-additive-verfahren/#Inline-Messtechnik
AN - OPUS4-50962
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Maierhofer, Christiane
A1 - Altenburg, Simon
A1 - Scheuschner, Nils
ED - Meyendorf, N.
ED - Ida, N.
ED - Singh, R.
ED - Vrana, J.
T1 - In Situ Real-Time Monitoring Versus Post NDE for Quality Assurance of Additively Manufactured Metal Parts
N2 - In this chapter, the current state-of-the-art of in situ monitoring and in situ NDE methods in additive manufacturing is summarized. The focus is set on methods, which are suitable for making statements about the quality and usability of a component currently being manufactured. This includes methods which can be used to determine state properties like temperature or density, other physical properties like electrical or thermal conductivity, the microstructure, the chemical composition, the actual geometry, or which enable the direct detection of defects like cracks, voids, delaminations, or inclusions. Thus, optical, thermographic, acoustic, and electromagnetic methods, as well as methods being suitable for investigating particle and fume emission are presented. The requirements of in situ monitoring methods with a focus on thermographic methods are discussed by considering different additive manufacturing processes like laser powder bed fusion (PBF-LB/M) and direct energy deposition (DED-LB/M). Examples of the successful implementation and applications of such monitoring methods at BAM are given. The in situ monitoring and NDE methods are compared against post-process NDE methods. The advantages and challenges of in situ methods concerning real-time data analysis and the application of AI algorithms are addressed and discussed.
KW - Additive manufacturing
KW - In situ monitoring
KW - In situ NDE
KW - Post NDE
KW - Thermography
KW - Laser powder bed fusion
KW - Direct energy deposition
PY - 2021
SN - 978-3-030-48200-8
DO - https://doi.org/10.1007/978-3-030-48200-8_51-1
SP - 1
EP - 37
PB - Springer Nature Switzerland AG
CY - Cham, Switzerland
ET - 1
AN - OPUS4-52824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Prozessüberwachung in der additiven Fertigung von Metallen an der BAM: Das Projekt ProMoAM
N2 - Vorstellung des TF-Projektes ProMoAM mit allen in-situ Verfahren und Referenzverfahren
T2 - Sitzung des VDI AK Mess- und Automatisierungstechnik
CY - Kassel, Germany
DA - 03.03.2020
KW - Additive manufacturing
KW - In situ monitoring
KW - Zerstörungsfreie Prüfung
PY - 2020
AN - OPUS4-53537
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Introduction to ProMoAM
N2 - A brief introduction to the project ProMoAM is given.
T2 - 2nd Workshop on In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys
CY - Online meeting
DA - 19.04.2021
KW - Additive Manufacturing
KW - Process monitoring
KW - ProMoAM
PY - 2021
AN - OPUS4-52513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Improving additive manufacturing technologies by in-situ monitoring: Thermography
N2 - Additive manufacturing of metals gains increasing relevance in the industrial field for part production. However, especially for safety relevant applications, a suitable quality assurance is needed. A time and cost efficient route to achieve this goal is in-situ monitoring of the build process. Here, the BAM project ProMoAM (Process monitoring in additive manufacturing) is briefly introduced and recent advances of BAM in the field of in-situ monitoring of the L-PBF and the LMD process using thermography are presented.
T2 - Anwenderkonferenz Infratec GmbH
CY - Online meeting
DA - 04.11.2021
KW - Additive Manufacturing
KW - Process monitoring
KW - Thermography
PY - 2021
AN - OPUS4-54026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
T1 - Summary of in-situ monitoring in additive manufacturing - ProMoAM
N2 - The quality of additively manufactured components is significantly influenced by the process parameters used during production. Thus, sensors and measuring systems are already commercially available for process monitoring, at least in metal-based additive manufacturing. However, it is not yet possible to detect defects and inhomogeneities directly or indirectly during the building process. The aim of the project ProMoAM is to develop spectroscopic and non-destructive testing methods for the in-situ evaluation of the quality of additively manufactured metal components in laser- or arc-based AM processes. In addition to passive and active methods of thermography, this includes optical tomography, optical emission spectroscopy, eddy current testing, laminography (radiography), X-ray backscattering, particle emission spectroscopy and photoacoustic methods.
T2 - 2nd Workshop on In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys
CY - Online meeting
DA - 19.04.2021
KW - In-situ monitoring
KW - Additive manufacturing
KW - Metals
KW - Thermography
PY - 2021
AN - OPUS4-52539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Multispectral in-situ monitoring of a L-PBF manufacturing process using three thermographic camera systems
N2 - The manufacturing of metal parts for the use in safety-relevant applications by Laser Powder Bed Fusion (L-PBF) demands a quality assurance of both part and process. Thermography is a nondestructive testing method that allows the in-situ determination of the thermal history of the produced part which is connected to the mechanical properties and the formation of defects [1]. A wide range of commercial thermographic camera systems working in different spectral ranges is available on the market. The understanding of the applicability of these cameras for qualitative and quantitative in-situ measurements in L-PBF is of vital importance [2]. In this study, the building process of a cylindrical specimen (Inconel 718) is monitored by three camera systems simultaniously. These camera systems are sensitive in various spectral bandwidths providing information in different temperature ranges. The performance of each camera system is explored in the context of the extraction of image features for the detection of defects. It is shown that the high temporal and thermal process dynamics are limiting factors on this matter. The combination of different spectral camera systems promises the potential of an improved defect detection by data fusion.
T2 - LASER SYMPOSIUM & ISAM 2021
CY - Online meeting
DA - 07.12.2021
KW - Laser Powder Bed Fusion
KW - Thermography
KW - In-situ Monitoring
KW - Defect detection
PY - 2021
AN - OPUS4-54141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Oster, Simon
A1 - Altenburg, Simon
A1 - Metz, C.
A1 - Maierhofer, Christiane
T1 - Aktive Laserthermografie im L-PBF-Prozess zur in-situ Detektion von Defekten
N2 - Die zerstörungsfreie Prüfung von metallischen Bauteilen hergestellt mit additiver Fertigung (Additive Manufacturing - AM) gewinnt zunehmend an industrieller Bedeutung. Grund dafür ist die Feststellung von Qualität, Reproduzierbarkeit und damit auch Sicherheit für Bauteile, die mittels AM gefertigt wurden. Jedoch wird noch immer ex-situ geprüft, wobei Defekte (z.B. Poren, Risse etc.) erst nach Prozessabschluss entdeckt werden. Übersteigen Anzahl und/oder Abmessung die vorgegebenen Grenzwerte für diese Defekte, so kommt es zu Ausschuss, was angesichts sehr langer Bauprozessdauern äußerst unrentabel ist. Eine Schwierigkeit ist dabei, dass manche Defekte sich erst zeitverzögert zum eigentlichen Materialauftrag bilden, z.B. durch thermische Spannungen oder Schmelzbadaktivitäten. Dementsprechend sind reine Monitoringansätze zur Detektion ggf. nicht ausreichend.
Daher wird in dieser Arbeit ein Verfahren zur aktiven Thermografie an dem AM-Prozess Laser Powder Bed Fusion (L-PBF) untersucht. Das Bauteil wird mit Hilfe des defokussierten Prozesslasers bei geringer Laserleistung zwischen den einzelnen gefertigten Lagen unabhängig vom eigentlichen Bauprozess erwärmt. Die entstehende Wärmesignatur wird ort- und zeitaufgelöst durch eine Infrarotkamera erfasst. Durch diese der Lagenfertigung nachgelagerte Prüfung werden auch zum Bauprozess zeitversetzte Defektbildungen nachweisbar.
In dieser Arbeit finden die Untersuchungen als Proof-of-Concept, losgelöst vom AM-Prozess, an einem typischen metallischen Testkörper statt. Dieser besitzt eine Nut als oberflächlichen Defekt. Die durchgeführten Messungen finden an einer eigens entwickelten L-PBF-Forschungsanlage innerhalb der Prozesskammer statt. Damit wird ein neuartiger Ansatz zur aktiven Thermografie für L-PBF erforscht, der eine größere Bandbreite an Defektarten auffindbar macht. Der Ansatz wird validiert und Genauigkeit sowie Auflösungsvermögen geprüft. Eine Anwendung am AM-Prozess wird damit direkt forciert und die dafür benötigten Zusammenhänge werden präsentiert.
T2 - DGZfP-Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Thermografie
KW - Zerstörungsfreie Prüfung
KW - Aktive Laserthermografie
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550353
SN - 978-3-947971-25-1
VL - 177
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V.
AN - OPUS4-55035
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Process monitoring in metal AM @ BAM - The project ProMoAM
N2 - Results of the project ProMoAM (Process monitoring in additive manufacturing) presented. Results from in-situ eddy current testing, optical emission spectroscopy, thermography, optical tomography as well as particle and gas emission spectroscopy are summarized and correlated to results from computed tomography for future in-situ defect detection.
T2 - 3rd Meeting of WG6 (NDT in AM) of the EFNDT
CY - Online meeting
DA - 15.03.2022
KW - Additive Manufacturing
KW - Process monitoring
KW - ProMoAM
PY - 2022
AN - OPUS4-54484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Towards hyperspectral in-situ temperature measurement in metal additive manufacturing
N2 - The industrial use of additive manufacturing for the production of metallic parts with high geometrical complexity and lot sizes close to one is rapidly increasing as a result of mass individualisation and applied safety relevant constructions. However, due to the high complexity of the production process, it is not yet fully understood and controlled, especially for changing (lot size one) part geometries.
Due to the thermal nature of the Laser-powder bed fusion (L-PBF) process – where parts are built up layer-wise by melting metal powder via laser - the properties of the produced part are strongly governed by its thermal history. Thus, a promising route for process monitoring is the use of thermography. However, the reconstruction of temperature information from thermographic data relies on the knowledge of the surface emissivity at each position on the part. Since the emissivity is strongly changing during the process due to phase changes, great temperature gradients, possible oxidation, and other potential influencing factors, the extraction of real temperature data from thermographic images is challenging. While the temperature development in and around the melt pool, where melting and solidification occur is most important for the development of the part properties. Also, the emissivity changes are most severe in this area, rendering the temperature deduction most challenging.
A possible route to overcome the entanglement of temperature and emissivity in the thermal radiation is the use of hyperspectral imaging in combination with temperature emissivity separation (TES) algorithms. As a first step towards the combined temperature and emissivity determination in the L-PBF process, here, we use a hyperspectral line camera system operating in the short-wave infrared region (0.9 µm to 1.7 µm) to measure the spectral radiance emitted. In this setup, the melt pool of the L-PBF process migrates through the camera’s 1D field of view, so that the radiation intensities are recorded simultaneously for multiple different wavelength ranges in a spatially resolved manner. At sufficiently high acquisition frame rate, an effective melt pool image can be reconstructed. Using the grey body approximation (emissivity is independent of the wavelength), a first, simple TES is performed, and the resulting emissivity and temperature values are compared to literature values. Subsequent work will include reference measurements of the spectral emissivity in different states allowing its analytical parametrisation as well as the adaption and optimisation of the TES algorithms. An illustration of the proposed method is shown in Fig.1.
The investigated method will allow to gain a deeper understanding of the L-PBF process, e.g., by quantitative validation of simulation results. Additionally, the results will provide a data basis for the development of less complex and cheaper sensor technologies for L-PBF in-process monitoring (or for related process), e.g., by using machine learning.
T2 - 21st International Conference on Photoacoustic and Photothermal Phenomena
CY - Bled, Slovenia
DA - 19.06.2022
KW - Thermography
KW - Additive manufacturing
KW - L-PBF
KW - Hyperspectral
PY - 2022
AN - OPUS4-55152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - Aktive Laserthermografie im L-PBF-Prozess zur in-situ Detektion von Defekten
N2 - Die zerstörungsfreie Prüfung von metallischen Bauteilen hergestellt mit additiver Fertigung (Additive Manufacturing - AM) gewinnt zunehmend an industrieller Bedeutung. Grund dafür ist die Feststellung von Qualität, Reproduzierbarkeit und damit auch Sicherheit für Bauteile, die mittels AM gefertigt wurden. Jedoch wird noch immer ex-situ geprüft, wobei Defekte (z.B. Poren, Risse etc.) erst nach Prozessabschluss entdeckt werden. Übersteigen Anzahl und/oder Abmessung die vorgegebenen Grenzwerte für diese Defekte, so kommt es zu Ausschuss, was angesichts sehr langer Bauprozessdauern äußerst unrentabel ist. Eine Schwierigkeit ist dabei, dass manche Defekte sich erst zeitverzögert zum eigentlichen Materialauftrag bilden, z.B. durch thermische Spannungen oder Schmelzbadaktivitäten. Dementsprechend sind reine Monitoringansätze zur Detektion ggf. nicht ausreichend.
Daher wird in dieser Arbeit ein Verfahren zur aktiven Thermografie an dem AM-Prozess Laser Powder Bed Fusion (L-PBF) untersucht. Das Bauteil wird mit Hilfe des defokussierten Prozesslasers bei geringer Laserleistung zwischen den einzelnen gefertigten Lagen unabhängig vom eigentlichen Bauprozess erwärmt. Die entstehende Wärmesignatur wird ort- und zeitaufgelöst durch eine Infrarotkamera erfasst. Durch diese der Lagenfertigung nachgelagerte Prüfung werden auch zum Bauprozess zeitversetzte Defektbildungen nachweisbar.
In dieser Arbeit finden die Untersuchungen als Proof-of-Concept, losgelöst vom AM-Prozess, an einem typischen metallischen Testkörper statt. Dieser besitzt eine Nut als oberflächlichen Defekt. Die durchgeführten Messungen finden an einer eigens entwickelten L-PBF-Forschungsanlage innerhalb der Prozesskammer statt. Damit wird ein neuartiger Ansatz zur aktiven Thermografie für L-PBF erforscht, der eine größere Bandbreite an Defektarten auffindbar macht. Der Ansatz wird validiert und Genauigkeit sowie Auflösungsvermögen geprüft. Eine Anwendung am AM-Prozess wird damit direkt forciert und die dafür benötigten Zusammenhänge werden präsentiert.
T2 - DGZfP-Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Thermografie
KW - Zerstörungsfreie Prüfung
KW - Aktive Laserthermografie
PY - 2022
AN - OPUS4-55040
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Porosity prediction in metal based additive manufacturing utilizing in situ thermography
N2 - Quality assessment of components produced by metal based additive manufacturing (AM) technologies such as laser powder bed fusion is rising in importance due to the increased use of AM in industrial production. Here, the presence of internal porosity was identified as a limiting factor for the final component quality. The utilization of thermography as an in-situ monitoring technique allows the determination of the part’s thermal history which was found to be connected to the porosity formation [1]. Combining the local thermal information derived from thermography with the porosity information obtained by x-ray micro computed tomography, machine learning algorithms can be utilized to predict the porosity distribution in the part. In this study, a first approach for the prediction of keyhole porosity in a cylindric specimen from AISI 316L stainless steel is presented. It is based on data augmentation using the “SmoteR” algorithm [2] to cure the dataset imbalance and a 1-dimensional convolutional neural network.
[1] C.S. Lough et al., Local prediction of Laser Powder Bed Fusion porosity by short-wave infrared thermal feature porosity probability maps. Journal of Materials Processing Technology, 302, p. 117473 (2022)
https://dx.doi.org/10.1016/j.imatprotec.2021.117473
[2] L. Torgo et al., SMOTE for Regression. Progress in Artificial Intelligence, Chapter 33, p. 378-289 (2013)
https://dx.doi.org/10.1007/978-3-642-40669-0_33
T2 - KI-Tag Arbeitskreis Chemometrik & Qualitätssicherung - Chemometrics meets Artificial Intelligence
CY - Berlin, Germany
DA - 01.04.2022
KW - Laser Powder Bed Fusion
KW - Thermography
KW - Defect Prediction
KW - Convolutional Neural Networks
PY - 2022
AN - OPUS4-54621
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
A1 - Scheuschner, Nils
A1 - Chand, Keerthana
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Heinrichsdorff, F.
A1 - Altenburg, Simon
T1 - From Thermographic In-situ Monitoring to Porosity Detection – A Deep Learning Framework for Quality Control in Laser Powder Bed Fusion
N2 - In this study, we present an enhanced deep learning framework for the prediction of porosity based on thermographic in-situ monitoring data of laser powder bed fusion processes. The manufacturing of two cuboid specimens from Haynes 282 (Ni-based alloy) powder was monitored by a short-wave infrared camera. We use thermogram feature data and x-ray computed tomography data to train a convolutional neural network classifier. The classifier is used to perform a multi-class prediction of the spatially resolved porosity level in small sub-volumes of the specimen bulk.
T2 - SMSI - Sensor and Measurement Science International 2023
CY - Nürnberg, Germany
DA - 08.05.2023
KW - Porosity
KW - Laser powder bed fusion
KW - In-situ monitoring
KW - Thermography
KW - Machine Learning
PY - 2023
UR - https://www.ama-science.org/proceedings/details/4404
DO - https://doi.org/10.5162/SMSI2023/C5.4
SP - 179
EP - 180
AN - OPUS4-57616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - From Thermographic In-situ Monitoring to Porosity Detection – A Deep Learning Framework for Quality Control in Laser Powder Bed Fusion
N2 - In this study, we present an enhanced deep learning framework for the prediction of porosity based on thermographic in-situ monitoring data of laser powder bed fusion processes. The manufacturing of two cuboid specimens from Haynes 282 (Ni-based alloy) powder was monitored by a short-wave infrared camera. We use thermogram feature data and x-ray computed tomography data to train a convolutional neural network classifier. The classifier is used to perform a multi-class prediction of the spatially resolved porosity level in small sub-volumes of the specimen bulk.
T2 - Sensor and Measurement Science International
CY - Nurnberg, Germany
DA - 08.05.2023
KW - Laser powder bed fusion
KW - In-situ monitoring
KW - Thermography
KW - Machine Learning
KW - Porosity
PY - 2023
AN - OPUS4-57614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Tina
T1 - Multi measurand in-situ monitoring of the laser powder bed fusion process by means of multispectral optical tomography
N2 - Laser Powder Bed Fusion (L-PBF), as one of the most promising production process in the field of metal additive manufacturing, enables traditional constructive solutions to be rethought and the manufacturing of optimized components according to the "form follows function" principle. The most significant obstacle for a broad industrial application of the L-PBF process is the inadequate quality assurance during the manufacturing process so far, leading to high production costs. Although several mainly camera based commercial in-process monitoring systems are already available, a deep understanding of the interpretation of the monitored data and correlation with actual defects is still lacking. One reason for this is the reduction of the complex process signature to just one measurement value.
The focus of this contribution is the presentation of the multispectral optical tomography as alternative to single measurand in-situ monitoring systems. The potential of this approach is hereby shown on L-PBF printed samples with induced process instabilities. Beyond that, an in-house developed L-PBF printer for further testing of multi-sensor in-situ monitoring systems is presented.
T2 - ICAM2021
CY - Online meeting
DA - 01.11.2021
KW - In-situ monitoring
KW - L-PBF
KW - Optical tomography
KW - 3d printing
KW - Thermography
PY - 2021
AN - OPUS4-54388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Börner, Andreas
T1 - Ultraschallunterstütztes Schlichtfräsen einer schwer spanbaren FeNi-Legierung
N2 - Zunächst wird die BAM vorgestellt. Anschließend wird die Messung bzw. Bestimmung der Amplitude der Ultraschallunterstützung erläutert, gefolgt von Schlichtfräsexperimenten an AM-Bauteilen aus einer schwer spanbaren FeNi-Legierung. Es werden die Ergebnisse der Zerspankraft, der Rauheit und der Eigenspannungen vorgestellt.
T2 - Ultrasonic Seminar
CY - Stipshausen, Germany
DA - 08.09.2022
KW - Ultraschallunterstütztes Fräsen
KW - Alloy 36
KW - Schwer spanbar
KW - Additive Fertigung
PY - 2022
AN - OPUS4-55709
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Influence of the WAAM process on residual stresses in high-strength steels (IIW-Doc. II-A-408-2022)
N2 - High-strength fine-grain structeural steels have great potential for weight optimization of many modern engineering structures. Efficient manufacturing can be achieved here above all by Wire Arc Additive Manufacturing (WAAM). First commercial high-strength welding consumables for WAAM are already available. However, due to a lack of knowledge and guidelines for the industry regarding welding residual stresses and component safety in manufacturing and operation, their application is still severely limited. Residual stresses play a crucial role here, as the sensitive microstructure of high-strength steels carries a high risk of cold cracking. For this reason, process- and material-related influences, as well as the design aspects on residual stress formation and the risk of cold cracking, are being investigated in a recent project (FOSTA-P1380/IGF21162BG). This high strength of the WAAM welding consumables is adjusted via a martensitic phase transformation. The volume expansion associated with martensite formation has a significant influence on residual stress evolution. However, this has not yet been investigated in relation to the processing of high-strength steels by WAAM. The aim of this work is to establish a WAAM cold crack test and easy-to-apply processing recommendations that will allow economical, expedient, and crack-resistant fabrication of high-strength steels, especially for SME. This paper focuses on the analysis of the effects of welding heat control and design of WAAM components on cooling conditions, microstructure, mechanical-technological properties and residual stresses. For this purpose, geometrically defined specimens (hollow cuboids) are welded fully automatically with a special, high-strength WAAM solid wire (yield strength >790 MPa). The heat control and specimen dimensions are varied within a statistical experimental design. The weld heat control is adjusted in such a way that the t8/5 cooling times are ensured within the recommended processing range (approx. 5–20 s). For this purpose, additional thermo-physical forming simulations using a dilatometer allowed the complex heat cycles to be reproduced and the resulting ultimate tensile strength of the weld metal to be determined. The WAAM welding of complex geometries with varying welding heat control and geometric factors or wall thicknesses not only has an effect on the cooling conditions, cooling times and microstructure, but also has a significant influence on the structural restraint conditions during welding. Hence, the welding experiments show significant effects of specimen scaling and heat input on the welding residual stresses, which may be detrimental regarding component properties and crack-critical tensile residual stresses. These complex interactions are analyzed within this investigation.
T2 - Intermediate Meeting of IIW Comissions II and IX
CY - Online meeting
DA - 17.03.2022
KW - MAG-Welding
KW - Additive Manufacturing
KW - Residual stresses
KW - high-strength steel
KW - cold cracking safety
PY - 2022
AN - OPUS4-56712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
T1 - Innovatives Instandsetzungsschweißen von Altstahl: Materialverhalten und Herausforderungen
N2 - Aus Gründen der Nachhaltigkeit und Wirtschaftlichkeit gibt es in der stahlverarbeitenden Industrie einen Trend zum Bauen im Bestand, um kostenintensive Sperrungen oder Rückbau zu vermeiden. Schweißen wird dabei als wirtschaftliches Fügeverfahren im Zusammenhang mit Altstählen kaum genutzt, obwohl Nieten- und Schraubenverbindungen oft unwirtschaftlich sind. Für die Instandsetzung ist häufig beschädigtes Bestandsmaterial durch neue Stähle zu ersetzen bzw. Alt-Neu-Stahl-Mischverbindungen herzustellen. Aufgrund der verschiedenen Herstellungsprozesse von Altstählen ist nicht jeder Stahl aus dem 20. Jahrhundert schweißgeeignet. Daher ist zunächst eine Schweißeignungsprüfung erforderlich. In den vorliegenden Untersuchungen wurden verschiedene Altstähle hinsichtlich ihres Schweißverhaltens mittels Dilatometrie analysiert. Ziel war es, eine Datenbasis aus Schweiß-Zustands-Zeit-Diagrammen und Simulationen der Wärmeeinflusszone zu erstellen, um praxisrelevante Schweißuntersuchungen ableiten zu können. Diese geben wesentlichen Aufschluss hinsichtlich ihres schweißmetallurgischen Verhaltens und ihrer Schweißeignung. Solche Grundlagen sind zur Entwicklung innovativer schweißtechnischer Konzepte zur beanspruchungsgerechten Instandsetzung bestehender Altstahl-Infrastruktur in Deutschland notwendig.
T2 - 6. Niedersächsisches Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - Altstahl
KW - Schweiß-ZTU Diagramme
KW - Instandsetzungsschweißen
KW - Schweißeignungsprüfung
KW - Dilatometrie
PY - 2025
AN - OPUS4-62629
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
A1 - Schaupp, Thomas
A1 - Zavdoveev, Anatoly
T1 - Challenges for testing hydrogen-assisted cold cracking in weld seams of high-strength steel grades
N2 - Hydrogen can cause weld cold cracking even days after fabrication. In this respect, higher strength steels present a challenge to established cold crack testing. In general, the tolerable hydrogen concentration for crack prevention decreases with increasing material strength. In addition, advanced welding processes require changes in weld geometry and heat input. This directly influences the formation of crack-critical microstructures, e.g. in hardened areas of the heat-affected zone. The limits of use and application of modern cold cracking tests are evaluated by (1) the externally loaded Implant-test and (2) the self-restraint Tekken-test. In particular, external mechanical stresses, which cause additional mechanical loads on the components during welding, must be considered due to the component-specific stiffness of high-strength steels. Accompanying test methods for
determining hydrogen concentration and diffusion in welds are presented, such as carrier gas hot extraction for determining hydrogen concentration (ISO 3690) or temperature-dependent diffusion coefficients. These values are of great importance for a holistic approach to the evaluation of the cold cracking sensitivity of high strength steels.
KW - Hydrogen
KW - Welding
KW - Cold cracking test
KW - High-strength steel
PY - 2024
DO - https://doi.org/10.37434/tpwj2024.08.01
SN - 0957-798X
VL - 2024
IS - 8
SP - 3
EP - 9
PB - International Association "Welding"
CY - Kyiv, Ukraine
AN - OPUS4-60946
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Prüfkonzept für die Wasserstoffaufnahme beim Schweißen im Betrieb an Wasserstoffpipelines
N2 - Für eine effektive Nutzung von Wasserstoff ist zukünftig ein nationales, sowie europäisches Wasserstoffnetz aus Pipelines geplant. Schweißen an zukünftigen Wasserstoffpipelines im Betrieb (unter Gasfluss und Druck) ist dabei unumgänglich. Für Erdgaspipelines bestehen etablierte Reparaturkonzepte, wie z.B. das "Hot-tapping". Beim Schweißen an Wasserstoffpipelines muss jedoch eine erhöhte Wasserstoffaufnahme in das Pipelinematerial hinlänglich untersucht werden, um mögliche wasserstoffinduzierte Schädigungen auszuschließen. Im Rahmen des Projekts H2-SuD "Schweißen an in Betrieb befindlichen Wasserstoffpipelines" wurde ein Prüfkonzept für die Wasserstoffaufnahme beim Schweißen im Betrieb entwickelt, getestet und angewandt. Dabei wurden realitätsnahe Schweißexperimente an unter Druck stehenden Demonstratoren durchgeführt. Anschließend wurde eine kryogene Probenentnahmeprozedur etabliert und der diffusible Wasserstoffgehalt in den Proben via Trägergasheißextraktion (TGHE) ermittelt. Vielfältige Schweißexperimente an unter 50 bar bis 100 bar Druckwasserstoff stehenden Demonstratoren verschiedener Durchmesser (DN50, DN200) und Wandstärken (4,1 mm bis 7,8 mm) wurden mit unterschiedlichen Schweißparametern durchgeführt. Dabei wurde ein signifikanter Einfluss von Wandstärke, Streckenenergie, Schweißnahtgeometrie und Abkühlbedingung auf die Wasserstoffaufnahme nachgewiesen. Die Durchführbarkeit und Eignung des Prüfkonzepts wurde aufgezeigt.
T2 - Bacheloranden-, Masteranden-, Doktoranden Kolloquium (BMDK) OvGU Magdeburg
CY - Magdeburg, Germany
DA - 22.01.2025
KW - Reparaturschweißen
KW - Pipeline
KW - Wasserstoff
KW - Ferngasleitung
PY - 2025
AN - OPUS4-62502
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Wasserstoffunterstützte Kaltrissbildung in Schweißnähten hochfester Stahlgüten - Anforderungen an die Prüfung
N2 - Die Vortrag gibt einen Überblick, warum Kaltrissprüfung von geschweißten Stählen ständig weiterentwickelt werden muss. Am Beispiel des Implant- und Tekken-Tests werden die Einsatz- u. Anwendungsgrenzen bewertet. Zu berücksichtigen ist, dass beim Schweißen eine äußere mechan. Beanspruchung durch bauteilspezifische Steifigkeitsverhältnisse wirksam ist. Zusätzlich werden weiterführende Prüfverfahren zur Bestimmung der Wasserstoffkonzentration und -diffusion in Schweißnähten vorgestellt, wie die Trägergasheißextraktion (TGHE) für die Ermittlung der Wasserstoffkonzentration (ISO 3690) oder Hochtemperaturdiffusionskoeffizienten. Diese Werte sind für die schweißtechnische Praxis von großer Bedeutung, um Haltezeiten z.B. für das Wasserstoffarmglühen abzuleiten.
T2 - Tagung Werkstoffprüfung 2021
CY - Online meeting
DA - 02.12.2021
KW - Wasserstoff
KW - Kaltrissprüfung
KW - Schweißen
KW - Stahl
KW - Hochfest
PY - 2021
AN - OPUS4-53902
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Effect of deposition strategies on mechanical properties and residual stresses at the transition zone of component and substrate in hybrid DED-arc manufacturing
N2 - In hybrid additive manufacturing, components or semi-finished products manufactured by conventional primary forming are enhanced or modified by additive manufactured structures. The integration of additive manufacturing steps into existing production routes opens up significant economic and technical potential. However, systematic investigations focusing on the critical transition area between the specific properties of the substrate (like high-strength) and the additively manufactured component, made of specific filler material, are still lacking. Residual stresses heighten the risk of cold cracking, excessive distortion and a reduction in yield stress. This is particularly evident in sensitive transition areas, resulting from a complex interaction among the material used, process conditions, and component design. This risk can be minimized by an optimized layer structure in combination with suitable process parameters. The focus of the present study was to determine the influence of deposition strategy on the Δt8/5 cooling time, the mechanical properties and the residual stresses in order to establish a correlation between heat control, cooling conditions and residual stresses in the transition area of hybrid-additive components. This contributed to the knowledge regarding the safe avoidance of cold cracking, excessive distortion and a reduction in yield stress and the implementation of hybrid DED-arc manufacturing. The heat control was varied by means of the build-up strategy, heat input and working temperature such that the Δt8/5 cooling times corresponded to the recommended processing range. For the deposition strategy, significant effects were exhibited, in particular on the local residual stresses in the transition area. The working temperature showed a higher influence on cooling time, displacement and residual stresses than the heat input. A low working temperature of 100 °C produces almost twice as much deformation of the substrate plate in the tests compared to manufacturing at a high working temperature of 300 °C. Furthermore, compressive longitudinal residual stresses in the sensitive transition area are reduced from 500 MPa to approx. 100 MPa by adjusting the working temperature from 100 °C to 300 °C. Such complex interactions must be clarified comprehensively to provide users with easily applicable processing recommendations and standard specifications for an economical hybrid additive manufacturing of components, for example made of high-strength steels in the transition area.
T2 - 77th IIW Annual Assembly and International Conference on Welding and Joining
CY - Rhodes, Greece
DA - 06.07.2024
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2024
AN - OPUS4-61925
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Reparaturschweißen zukünftiger, in Betrieb befindlicher Wasserstoffpipelines
N2 - Wasserstoff leistet als Energieträger der Zukunft einen entscheidenden Beitrag zur nachhaltigen Energieversorgung. Der Transport wird vorwiegend durch das europäische Ferngasleitungsnetz erfolgen. Bisherige Untersuchungen zeigen, dass bisher verwendete Rohrstähle grundsätzlich für den Wasserstofftransport geeignet sind. Diese Eignung ist nicht direkt auf Reparaturfragestellungen im Betrieb übertragbar, da Schweißungen aus technisch-ökonomischen Gründen oft unter fortwährendem Gasfluss durchgeführt werden.
Ein im Erdgasnetz angewandtes Konzept ist das Anbohren druckführender Pipelines („Hot Tapping“). Dazu werden Zylinderhalbschalen zuerst durch Längs- und dann per Rohrrundnähten an die Pipeline geschweißt. Essenziell ist dabei die maßgeschneiderte Wärmeeinbringung, um das „Durchbrennen“ in die Pipeline zu vermeiden. Für zukünftige Wasserstoffpipelines liegt der Fokus u.a. auf dünnwandigen Leitungen. Im Gegensatz zu Erdgas, führen die beim Schweißen erreichten hohen Temperaturen an der Innenseite der Pipeline zu einer zusätzlichen Wasserstoffaufnahme in den Rohrstahl mit möglicher Materialdegradation.
Zur praktischen Lösung der Fragestellung, sind internationale Aktivitäten im Gang. Diese umfassen bspw. die Möglichkeiten und Weiterentwicklung von realistischen Prüfkonzepten (u.a. durch maßstäbliche Bauteilversuche). Dazu untersucht die Bundesanstalt für Materialforschung und -prüfung (BAM) in einem DVGW-geförderten Kooperationsprojekt mit Gasnetzbetreibern, die Frage der Übertragbarkeit der Schweißkonzepte der Erdgastechnik auf zukünftiger Wasserstoffpipelines.
T2 - DVS CONGRESS 2024
CY - Erfurt, Germany
DA - 16.09.2024
KW - Schweißen
KW - Reparatur
KW - Wasserstoff
KW - Pipeline
PY - 2024
AN - OPUS4-61076
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Reparaturschweißen zukünftiger, in Betrieb befindlicher Wasserstoffpipelines
N2 - Es existieren konkrete nationale und europäische Pläne für eine Wasserstoffpipeline Netz. Dieses soll in Zukunft eine Nachhaltige Energieversorgung von Industrie mit hohem energiebedarf sicherstellen. Dabei müssen zukünftige Wasserstoffpipelines aus wirtschaftlich und technischen Gründen im Betrieb gewartet, repariert oder erweitert werden. Die Übertragbarkeit von etablierten Reparaturkonzepten von Ergaspipelines, wie das "Hot-tapping", muss für Wasserstoffpipelines hinlänglich untersucht werden. Das Schweißen im Betrieb ist dabei unumgänglich. Durch eine erhöhte thermische Belastungen bei der Schweißprozedur muss die Wassestoffaufnahme in den Pipelinestahl ausgehend von der Innenwand der Pipeline und eine mögliche Materialdegradation (hydrogen embrittlement, HE) eingehend untersucht werden. Dazu wurden im Rahmen des Projekts "H2-SuD" zwei Prüfkonzepte entiwckelt. Ein Demonstrator Konzept (1) zur Bestimmung der Wasserstoffaufnahme durch realistische Reparaturschweißversuche an druckbeaufschlagten Demonstratoren und ein Prüfkonzept (2) mit vereinfachter Geometrie zur Messung von Wärmefeldern, die beim Reparaturschweißen entstehen. Erste Ergebnisse zur Wasserstoffaufnahme (1) und Temperaturmessungen (2) werden präsentiert und bewertet. Beide Prüfkonzepte bieten die experimentelle Grundlage zur Validierung von geplanten Temperatur- und Diffusionssimulationen von Reparaturschweißungen an Wasserstoffpipelines.
T2 - 1. Weiterbildungsveranstaltung 2025 des DVS BV Potsdam
CY - Götz, Germany
DA - 19.02.2025
KW - Reparaturschweißen
KW - Wasserstoff
KW - Pipeline
PY - 2025
AN - OPUS4-62606
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Component test for safety assessment of in-service welding on / onto pressurized hydrogen pipelines
N2 - Hydrogen is the energy carrier of tomorrow for a fossil-free future. This requires a reliable transport infrastructure capable of transporting large quantities of hydrogen, e.g. for the steel and chemical industries. In addition to the construction of new pipelines, the conversion of existing natural gas (NG) networks is an essential part of global hydrogen strategies. The transport of hydrogen is fundamentally different from that of NG, as hydrogen can be absorbed into the pipeline material. Given the known effects of hydrogen embrittlement, the compatibility of the materials for the proposed pipelines (typically low alloy steels in a wide range of strengths and thicknesses) must be investigated. However, pipelines require frequent maintenance, repair, or the need to install additional outlets. In some cases, it is necessary to perform welding on or to the pipelines while they are still in service, i.e. with active gas flow under high pressure, such as the well-known "hot tapping". This in-service welding poses challenges for hydrogen operations in terms of additional hydrogen absorption during welding and material compatibility. The challenge can be roughly divided into the possible austenitization of the inner pipe material exposed to hydrogen, which can lead to sufficient hydrogen absorption, and the welding itself, which causes an increased temperature range. Both lead to a significant increase in hydrogen solubility and diffusivity of the respective materials compared to room temperature. In this context, knowledge about hot tapping on hydrogen pipelines is scarce due to the lack of operational experience. Fundamental experimental investigations are required to investigate the transferability from natural gas to hydrogen pipeline networks. For this reason, the present study presents a specially designed mock-up / demonstrator concept for the realistic assessment of the welding process conditions.
T2 - Materials Week 2025
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Repair welding
PY - 2025
AN - OPUS4-62874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
T1 - Evaluation of welding on in-service pressurized hydrogen pipelines by component testing
N2 - Hydrogen transportation is fundamentally different from natural gas (NG) as it can be absorbed into the pipeline material. However, pipelines require frequent maintenance or repair, in some cases on or onto the pipelines while they are still under pressure. This in-service welding causes challenges for hydrogen operations. They can be roughly divided into: (1) possible austenitization of the inner pipe material exposed to hydrogen, and (2) welding itself with its temperature cycles. Both lead to a significant increase in hydrogen solubility/diffusivity of the materials. Fundamental investigations are required due to the missing service experience. The present study introduces a specially designed demonstrator concept for the assessment of the welding processing conditions. The mock-up was designed to enable temperature measurement during welding as well as ex-post extraction of samples for the quantification of the absorbed hydrogen. The necessary pressurized hydrogen volume was limited by the insertion of a solid cylinder. Welding experiments on the pressurized mock-ups (DN50 and DN200) have shown that the austenitization temperature is nearly reached on the inner surface of the pipeline. This corresponds to a significant hydrogen absorption of several ppm in the welded joint, especially for thin-walled pipelines. Nonetheless, a potential hydrogen assisted cracking was not identified.
T2 - 24. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
DA - 02.04.2025
KW - Pipeline
KW - In-Service
KW - Welding
KW - Hydrogen
PY - 2025
AN - OPUS4-62917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
A1 - Erxleben, Kjell
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Repair Welding of In-Service Hydrogen Pipelines - Concepts and Challenges
N2 - Hydrogen is set as the energy carrier of tomorrow for a more sustainable fossil fuel free future. As this necessitates a reliable transport infrastructure, repurposing of the existing natural gas grid is planned. With regards to the well-known effect of hydrogen embrittlement, the compatibility of utilized materials must be investigated. First comprehensive studies on pipeline material hydrogen compatibility indicate that these materials can be applied to a certain extent. Nonetheless, the material compatibility is currently of high interest and focus of numerous research projects worldwide. However, pipelines require frequent maintenance and repair work. As part of these, in some cases it is necessary to do weldments onto pipelines while they are pressurized. This in-service welding introduces additional challenges for the material compatibility. Due to the resulting high temperatures, the metallurgical changes in the material and of course the presence of high-pressure hydrogen in the pipeline, additional investigations need to be conducted to ensure that no critical material degradation because of increased hydrogen absorption occurs and an overall material compatibility is given. For this reason, the present paper introduces in-service welding on pipelines. An overview of current research projects that deal with the application of in-service welding specifically on hydrogen pipelines and the emerging problems when applying these techniques on hydrogen pipelines is given. Methods of material testing, their limits and possible solutions are presented and discussed.
T2 - 2024 15th International Pipeline Conference
CY - Calgary, Alberta, Canada
DA - 23.09.2024
KW - Hydrogen
KW - Pipeline
KW - Welding
KW - In-Service
PY - 2024
SN - 978-0-7918-8856-8
DO - https://doi.org/10.1115/IPC2024-133052
SP - 1
EP - 6
PB - The American Society of Mechanical Engineers (ASME)
CY - New York
AN - OPUS4-62262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Einfluss der Wärmeführung auf die Eigenschaften und fertigungsbedingten Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle
N2 - Hochfeste Feinkornbaustähle verfügen über ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Kommerzielle hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Derzeit ist jedoch eine breite industrielle Anwendung insbesondere für KMU aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse untersucht. Im Fokus dieser Analysen steht die Bestimmung der Wechselwirkungen zwischen WAAM-Prozessparametern bzw. der Wärmeführung auf das Gefüge und die Eigenspannungen. Hierfür werden Referenzproben als offene Hohlquader mit definierten Abmessungen vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die gezielte Einstellung der geometrischen Eigenschaften erfolgt durch Schweißparameter und Nahtaufbau bei ca. 4 kg/h mittlerer Abschmelzleistung. Die Wärmeführung wird innerhalb eines statistischen Versuchsplanes mittels Streckenenergie (200 kJ/m bis 650 kJ/m) und Zwischenlagentemperatur (100 °C bis 300 °C) so variiert, dass die t8/5-Abkühlzeiten dem empfohlenen Verarbeitungsbereich entsprechen (ca. 5 s bis 20 s). Ziel ist es bei konstanten geometrisch-konstruktiven Randbedingungen, den Einfluss der Wärmeführung auf Gefüge und resultierende Eigenspannungen zu analysieren. Darüber hinaus erfolgt die Bestimmung des Einflusses der t8/5-Abkühlzeit auf die mechanisch-technologischen Eigenschaften des speziellen, hochfesten WAAM-Massivdrahts mithilfe von Dilatometeranalysen. Für die Streckenenergie können neben den Gefügeeinflüssen aufgrund der resultierenden Abkühlzeit deutliche Effekte insbesondere auf die lokalen Eigenspannungen im Bauteil belegt werden. Das Schweißen mit zu hoher Wärmeeinbringung bzw. Abschmelzleistung kann zu ungünstigen Gefüge- und Bauteileigenschaften führen, gleichzeitig jedoch niedrigere Zugeigenspannungsniveaus bewirken. Die Dilatometeranalysen zeigen für den untersuchten WAAM-Schweißzusatzwerkstoff eine großes t8/5-Zeitfenster mit einer vergleichsweise geringen Abnahme der Zugfestigkeit mit zunehmender t8/5-Abkühlzeit. Solche komplexen Wechselwirkungen gilt es letztlich mit diesen Untersuchungen zu klären, um leicht anwendbare Verarbeitungsempfehlungen und Normvorgaben für ein wirtschaftliches, anforderungsgerechtes und risssicheres WAAM von hochfesten Stählen den Anwendern zur Verfügung zu stellen.
T2 - 42. Assistentenseminar Fügetechnik
CY - Braunschweig, Germany
DA - 06.10.2021
KW - MAG-Schweißen
KW - Eigenspannungen
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Kaltrisssicherheit
PY - 2021
AN - OPUS4-56691
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
T1 - Challenges in the evaluation of the weldability of old mild steels for future use
N2 - From the middle of the 19th century, the development and implementation of completely new manufacturing processes meant that molten steel could be produced in almost any quantity. This enabled the widespread use of the steels from this time, whose area of application was considerably expanded. Numerous structures built on this basis are still in operation today and represent an essential part of the infrastructure. For example, around 50 % of the bridges and engineering structures in the German railway network are over 80 years old, with around 80 % of these structures having existed for more than 100 years. Similarly, around 6,000 bridges in Germany's road network were built more than 80 years ago. Particularly, today high level of loads due to railway/road traffic (masses, speed etc.) intensifies the importance of maintaining and repairing these structures. The focus of these measures is to enable the structures to fulfil future requirements.
As earlier constructions were predominantly designed for screws and rivet joints, old steels were originally manufactured without considering their suitability for welding. In addition, for historical steel structures there is often insufficient or no documentation available. This includes data on material specifications such as the chemical composition, information on the mechanical-technological properties and on the manufacturing process used. These missing information poses a major challenge for the assessment of the steels suitability for welding. Furthermore, old steels are characterised by a typical macrostructure. Depending on whether the manufacturing process is a cast steel process or ingot casting (currently continuous casting), the question arises as to the type of deoxidisation (non-/deoxidized). In the case of non-deoxidized old mild steels, a relatively clean, dense surface layer, the so-called ‘rim-layer’, forms during the solidification of the steel ingot. Towards the centre of the sheet cross-section however, the remaining molten metal becomes increasingly enriched with tramp elements such as sulphur and phosphorus. This so-called segregation layer makes fault-free welding significantly more difficult, as depending on the heat input, chemical composition and the filler metal used, hot cracking, the risk of brittle fracture and a tendency to terrace fracture can be expected. Thus, an individual assessment of the suitability for welding of each old steel charge used in such old structures, that must be repaired is necessary.
T2 - 78th Annual Assembly and International Conference
CY - Genoa, Italy
DA - 22.06.2025
KW - Old mild Steels
KW - Weld-CCT diagrams
KW - Suitability for welding
KW - Dilatometry
KW - Repair measures
PY - 2025
AN - OPUS4-63649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Zuverlässige Wasserstoffbestimmung in Metallen und ihren Schweißverbindungen: Parameter, Einflüsse, Grenzen
N2 - Im Zuge der wasserstoffbasierten Energiewirtschaft von morgen, kommt der Errichtung der dementsprechenden Infrastruktur die zentrale Rolle zu. Der überwiegende Teil bisher eingesetzter und meist geschweißter Werkstoffe, wie Stähle, kann unter bestimmten Bedingungen zur Wasserstoffversprödung neigen. Dies umfasst die klassische verzögerte Kaltrissbildung während der Schweißverarbeitung als auch Versprödungsphänomene während des Betriebs. Für die Bewertung eines jeden Wasserstoffeffektes auf bspw. die mechanischen Eigenschaften eines geschweißten metallischen Werkstoffes, muss der Wasserstoffgehalt präzise bestimmt werden, Im Fall von Schweißnähten ist die beispielsweise nach der ISO 3690, die klassische isotherme Trägergas-Heißextraktion (TGHE). Die TGHE basiert dabei auf der beschleunigten Wasserstoffentgasung aufgrund der thermischen Aktivierung des Wasserstoffs bei erhöhten Temperaturen. Neben der reinen Quantifizierung des Wasserstoffs, kann über die thermische Desorptionsanalyse (TDA) mit variierten Heizraten, der Bindungszustand an mikrostrukturellen Defekten im Material festgestellt und bewertet werden. Für beide Techniken sind experimentelle und messtechnische Einflüsse zu beachten, die großen Effekt auf das Ergebnis haben. Für die TGHE schlägt die ISO 3690 schlägt beispielswiese verschiedene Probengeometrien sowie Mindestextraktionszeiten vor. Die vorliegende Studie fasst Ergebnisse und Erfahrungen zahlreicher Untersuchungen an der Bundesanstalt für Materialforschung und -prüfung (BAM) mit unterschiedlichen Probentemperaturen und Geometrien (ISO 3690 Typ B und zylindrische TDA-Proben) zusammen hinsichtlich: Einfluss der Probenoberfläche (poliert/geschweißt), Messgenauigkeiten in Abhängigkeit des Probenvolumens sowie die unzureichende Überwachung des Effektes des PI-Reglers auf die Extraktionstemperatur. Insbesondere eine abweichende Extraktionstemperatur zur eingestellten Temperatur, kann die Messergebnisse wesentlich verfälschen. Basierend auf den Ergebnissen werden Methoden aufgezeigt, um schnell die gewünschte Extraktionstemperatur zu erreichen, ohne physisch in das Messequipment eingreifen zu müssen. Dies dient der wesentlichen Verbesserung der Zuverlässigkeit der Wasserstoffmessung durch erhöhte Signalstabilität und beschleunigte Wasserstoffdesorption. Im Allgemeinen ist eine unabhängige Temperaturmessung mit Dummy-Proben für die gewählte Heizprozedur angeraten, um mögliche unerwünschte Temperatureinflüsse bereits vor der Messung auszuschließen. Die beschriebenen Methoden können ohne großen Aufwand direkt in die industrielle Anwendung überführt werden.
T2 - DVS Congress 2023
CY - Essen, Germany
DA - 11.09.2023
KW - Wasserstoff
KW - Messung
KW - Trägergasheißextraktion
KW - ISO 3690
KW - Schweißverbindung
PY - 2023
AN - OPUS4-58307
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, Julien
A1 - Hübler, Daniela
A1 - Schröpfer, Dirk
A1 - Börner, Andreas
A1 - Kannengießer, Thomas
ED - Hanke, S.
T1 - Wear behavior of innovative niobium carbide cutting tools in ultrasonic-assisted finishing milling
N2 - The resources of niobium exceed the ones of tungsten by an order of magnitude. With 92%, Brazil is today the main global producer of niobium. Hence, niobium carbides (NbC) are a sustainable and economic alternative to conventionally used cutting materials, especially tungsten carbides (WC). Moreover, NbC can be used in Ni alloy matrix and thus offer significant advantages by substituting WC in Co matrix as cutting materials in terms of health risks and raw material price and supply risk. Based on recent studies which found an increased performance of NbC compared to WC cutting tools in machining higher strength steels, the composition NbC12Ni4Mo4VC was chosen for finish machining of a high-strength steel S960QL in this study. The experiments were carried out on an ultrasonic-assisted 5-axis milling machine using NbC tools specially made to benchmark them with commercially available coated WC cutting inserts. In addition, the influence of a coating system for the NbC inserts is tested and evaluated for its performance in the cutting process. Tool wear and cutting force analyses are implied to identify optimal parameter combinations as well as tool properties for the novel NbC tool. Together with the oscillation of ultrasonic-assisted milling, the loads on the component surface and the tool can be reduced and the wear behavior of the novel NbC tool can be refined. These milling tests are accompanied by standardized wear tests, i.e., pin-on-disc, between the aforementioned material combinations, and the results are correlated with each other. Finally, the behavior when using hard-to-cut materials such as Ni alloys, or innovative materials such as iron aluminide is also being tested, as these are constantly in the focus of machining optimization. With this strategy, comprehensive knowledge is achievable for future efficient application of NbC for milling tools, which have already been researched for decades using WC.
T2 - 24th International Conference on Wear of Materials
CY - Banff, Canada
DA - 16.04.2023
KW - Niobium carbide
KW - Cutting tool
KW - Ultrasonic-assisted milling
KW - Tool wear
PY - 2023
DO - https://doi.org/10.1016/j.wear.2023.204722
SN - 0043-1648
VL - 522
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-57561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmitt, Johannes
T1 - Data acquisition system for single particle inductively coupled plasma mass spectrometry (spICP-MS) with nanosecond time resolution
N2 - This study presents our data acquisition system prototype for single particle inductively coupled plasma mass spectrometry (spICP-MS) with nanosecond time resolution (nanoDAQ) and a matching data processing approach for time-resolved data in the nanosecond range. The system continuously samples the secondary electron multiplier (SEM) detector signal with a dwell time of approximately 2 ns and enables detection of gold nanoparticles (AuNP) as small as 7.5 nm with a commercial single quadrupole ICP-MS instrument. [1]
Analysis of acquired transient data is based on the temporal distance between detector events and a derived ion event density. It was shown that the inverse logarithm of the distance between detector events is proportional to particle size. Also, the number of detector events per particle can be used to calibrate and determine the particle number concentration (PNC) of a nanoparticle dispersion.
Particle-by-particle-based analysis of ion event density and other parameters derived from nanosecond time resolution show promising results. High data acquisition frequency of the systems allows recording of a statistically significant number of data points in 60 s or less, which leaves only the sample uptake and rinsing steps as remaining factors for limiting the total measurement time.
T2 - 20th European Winter Conference on Plasma Spectrochemistry
CY - Berlin, Germany
DA - 02.03.2025
KW - ICP-MS
KW - Instrumentation
KW - Nano
KW - Nanoparticle Characterization
PY - 2025
AN - OPUS4-63599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Alloy Modification and ultrasonic assisted milling of wear resistant alloys with defined surfaces
N2 - The targets for reducing CO2 emissions are closely linked to the development of highly efficient and economical steel components in plant, process and power plant technology, which require wear protection coatings tailored to the application and steel material for high combined corrosive, tribological, thermal and mechanical stresses. There is a growing demand in industry for defined functional surfaces of high quality for these coatings. Milling is a standard process for finish machining. The desired properties of wear resistant alloys imply significant challenges for the milling process due to high tool wear and surface defects. Besides the hardness of the coating materials, especially due to the precipitations, inhomogeneous, anisotropic weld structures of the claddings lead to further deteriorations of milling processes due to unstable milling conditions and process forces.
A joint project of BAM and ISAF of TU Clausthal (Fosta P1550/IGF 21959 N) investigates the optimization of these challenging machining conditions by means of alloy modifications of the welding powder for plasma transferred arc cladding, without reducing the wear protection potential and using ultrasonic assisted milling process.
In this paper, the influence of the microstructure and precipitation morphology adjusted by means of alloy modification on machining for a NiCrMoSiFeB alloy (trade name: Colmonoy 56 PTA) is investigated. Through metallurgical investigations and in-situ measurement of cutting forces and temperatures at the cutting edge during the milling process as well as the subsequent investigation of tool wear and surface integrity, a detailed analysis and correlation between microstructural properties and machinability is feasible. The findings allow recommendations for standards and processing guidelines, enabling safe and economical production of highly stressed steel components with non-critical, cost-reduced materials.
T2 - IIW Annual Assembly
CY - Singapore
DA - 16.07.2023
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
KW - Zerspankräfte
PY - 2023
AN - OPUS4-59087
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Alloy Modification and ultrasonic assisted milling of wear resistant alloys with defined surfaces
N2 - The targets for reducing CO2 emissions are closely linked to the development of highly efficient and economical steel components in plant, process and power plant technology, which require wear protection coatings tailored to the application and steel material for high combined corrosive, tribological, thermal and mechanical stresses. In addition to increasing demands to replace conventional cobalt alloys with nickel alloys as a result of price and supply risks, there is a growing demand in industry for defined functional surfaces of high quality for these coatings. Milling is a standard process for finish machining. The desired properties of wear resistant alloys imply significant challenges for the milling process due to high tool wear and surface defects. Besides the hardness of the coating materials, especially due to the precipitations, inhomogeneous, anisotropic weld structures of the claddings lead to further deteriorations of milling processes due to unstable milling conditions and process forces.
A joint project of BAM and ISAF of TU Clausthal (Fosta P1550/IGF 21959 N) investigates the optimization of these challenging machining conditions by means of alloy modifications of the welding powder for plasma transferred arc cladding, without reducing the wear protection potential and using ultrasonic assisted milling process.
In this paper, the influence of the microstructure and precipitation morphology adjusted by means of alloy modification on machining is investigated. The alloy used is a NiCrMoSiFeB alloy (trade name: Colmonoy 56 PTA). Through metallurgical investigations and in-situ measurement of cutting forces and temperatures at the cutting edge during the milling process as well as the subsequent investigation of tool wear and surface integrity, a detailed analysis and correlation between microstructural properties and machinability is feasible. The findings allow recommendations for standards and processing guidelines, enabling safe and economical production of highly stressed steel components with non-critical, cost-reduced materials.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Magdeburg, Germany
DA - 31.05.2023
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
KW - Zerspankräfte
PY - 2023
AN - OPUS4-59212
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Alloy modification and ultrasonic assisted milling of wear resistant alloys with defined surfaces
N2 - The targets for reducing CO2 emissions are closely linked to the development of highly efficient and economical steel components in plant, process and power plant technology, which require wear protection coatings tailored to the application and steel material for high combined corrosive, tribological, thermal and mechanical stresses. In addition to increasing demands to replace conventional cobalt alloys with nickel alloys as a result of price and supply risks, there is a growing demand in industry for defined functional surfaces of high quality for these coatings. Milling is a standard process for finish machining. The desired properties of wear resistant alloys imply significant challenges for the milling process due to high tool wear and surface defects. Besides the hardness of the coating materials, especially due to the precipitations, inhomogeneous, anisotropic weld structures of the claddings lead to further deteriorations of milling processes due to unstable milling conditions and process forces.
A joint project of BAM and ISAF of TU Clausthal (Fosta P1550/IGF 21959 N) investigates the optimization of these challenging machining conditions by means of alloy modifications of the welding powder for plasma transferred arc cladding, without reducing the wear protection potential and using ultrasonic assisted milling process.
In this paper, the influence of the microstructure and precipitation morphology adjusted by means of alloy modification on machining is investigated. The alloy used is a NiCrMoSiFeB alloy (trade name: Colmonoy 56 PTA). Through metallurgical investigations and in-situ measurement of cutting forces and temperatures at the cutting edge during the milling process as well as the subsequent investigation of tool wear and surface integrity, a detailed analysis and correlation between microstructural properties and machinability is feasible. The findings allow recommendations for standards and processing guidelines, enabling safe and economical production of highly stressed steel components with non-critical, cost-reduced materials.
T2 - European steel technology and application days
CY - Düsseldorf, Germany
DA - 12.06.2023
KW - Ultrasonic assisted milling
KW - Surface integrity
KW - Tool wear
PY - 2023
AN - OPUS4-58945
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Alloy Modification and ultrasonic assisted milling of wear resistant alloys with defined surfaces
N2 - The targets for reducing CO2 emissions are closely linked to the development of highly efficient and economical steel components in plant, process and power plant technology, which require wear protection coatings tailored to the application and steel material for high combined corrosive, tribological, thermal and mechanical stresses. There is a growing demand in industry for defined functional surfaces of high quality for these coatings. Milling is a standard process for finish machining. The desired properties of wear resistant alloys imply significant challenges for the milling process due to high tool wear and surface defects. Besides the hardness of the coating materials, especially due to the precipitations, inhomogeneous, anisotropic weld structures of the claddings lead to further deteriorations of milling processes due to unstable milling conditions and process forces.
A joint project of BAM and ISAF of TU Clausthal (Fosta P1550/IGF 21959 N) investigates the optimization of these challenging machining conditions by means of alloy modifications of the welding powder for plasma transferred arc cladding, without reducing the wear protection potential and using ultrasonic assisted milling process.
In this paper, the influence of the microstructure and precipitation morphology adjusted by means of alloy modification on machining for a NiCrMoSiFeB alloy (trade name: Colmonoy 56 PTA) is investigated. Through metallurgical investigations and in-situ measurement of cutting forces and temperatures at the cutting edge during the milling process as well as the subsequent investigation of tool wear and surface integrity, a detailed analysis and correlation between microstructural properties and machinability is feasible. The findings allow recommendations for standards and processing guidelines, enabling safe and economical production of highly stressed steel components with non-critical, cost-reduced materials.
T2 - IIW Intermediate meeting of Commission II-A
CY - Garching, Germany
DA - 06.03.2023
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
PY - 2023
AN - OPUS4-59086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Investigation of the influence of PWHT heating rate and global stress conditions on the stress relief cracking mechanism of CrMoV steel SAW joints
N2 - This presentation summarizes the latest research results of the influence of the post weld heat treatment (PWHT) rate and
the global mechanical stress conditions on the stress relief cracking (SRC) susceptibility of low-alloyed and creep-resistant CrMoV steel submerged arc weld joints. It was found that a certain effect of very low heating rates could be confirmed. In addition, the interlinking of SRC susceptibility increasing effects during the PWHT and the ex-post indentification in metallographic cross-section via microstructure characterization is very complex.
T2 - IIW Intermediate meeting of Commission II-A
CY - Garching, Germany
DA - 06.03.2023
KW - Creep-resistant steel
KW - Submerged arc welding
KW - Stress relief cracking
KW - Heating rate
KW - Microstructure characterization
PY - 2023
AN - OPUS4-57116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Alloy modification for additive manufactured Ni alloy components Part I: Effect on microstructure and hardness
N2 - Alloy 36 is an iron-based alloy with 36% nickel. It is used in applications in which dimensional stability is critical, such as molding tools for composite materials in aerospace and automotive applications. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components. Additively manufactured components have a heterogeneous microstructure and anisotropic mechanical properties. In addition, the manufactured components require subsequent machining surface finishing due to the high requirements. Nickel iron alloys are difficult to machine. Additionally, inhomogeneous microstructure may lead to unstable cutting forces and conditions. Alloy modifications are made to the alloy 36. For this purpose, titanium, zirconium and niobium are added up to 1 % by mass each. Plasma-Transferred-Arc is used for the welding tests. The hardness profile is determined on the transverse section. The initial structure as well as the modifications have an austenitic structure. The microstructure of the modifications of Alloy 36 with 1% Ti and 1% Zr is not refined, instead the grain size increases.
T2 - IIW C-II Intermediate meeting
CY - Online meeting
DA - 17.03.2022
KW - Alloy modification
KW - Alloy 36
KW - Additive manufacturing
PY - 2022
AN - OPUS4-56622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Optimisation of surface residual stresses using hybrid milling processes for additive manufactured Nickel alloy components
N2 - Ni alloys are cost intensive materials and generally classified as difficult-to-cut materials. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. Recent studies exhibited that hybrid machining processes, such as ultrasonic-assisted milling (USAM), are suitable for achieving favourable residual stress states at the surface of difficult-to-cut Ni-Cr alloys. In this investigation, wire arc additive manufactured (WAAM) specimens of alloy 36 were finish milled under different milling conditions. In addition to the machined surfaces condition and topology, the surface-near residual stresses were analysed using X-ray diffraction (XRD). Especially for low cutting speeds, significantly improved surface properties, roughness parameters and lower mechanical and microstructural degradations were found for the specimen machined with USAM compared to conventional milling. The improved surface integrity could furthermore be observed by a significant reduction of the tensile residual stresses in the surface boundary area.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium, Otto-von-Guericke-Universität Magdeburg
CY - Magdeburg, Germany
DA - 18.05.2022
KW - Surface integrity
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - Ni alloy
KW - Alloy 36
PY - 2022
AN - OPUS4-54908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Ghigo, Tea
A1 - Rabin, Ira
T1 - Gaining Perspective into the Materiality of Manuscripts: The Contribution of Archaeometry to the Study of the Inks of the White Monastery Codices
N2 - An interdisciplinary approach to the study of manuscript traditions is here applied to the analysis of the leaves from the White Monastery, one of the greatest centres of literary production in Late Antique Egypt. In the framework of the ‘PAThs’ project, archaeometric analyses complement the information pieced together by a range of disciplines in the field of humanities. The use of different complementary analytical techniques provides information on the type of ink used and its elemental composition, unveiling interesting details regarding the materials and methodology of manufacturing of writing media. Moreover, this contribution takes a step forward and discusses the possible existence of a regional arrangement in the elemental composition revealed in the inks studied.
KW - Manuscript making
KW - Archaeometry
KW - Ink analysis
KW - Interdisciplinary approach
KW - Coptic studies
PY - 2020
SP - 273
EP - 282
AN - OPUS4-51003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maltomini, F.
A1 - Ghigo, T.
A1 - Hahn, Oliver
A1 - Rabin, Ira
ED - Fournet, J.-L.
ED - Kramer, B.
ED - Luppe, W.
ED - Maehler, H.
ED - McGing, B.
ED - Poethke, G.
ED - Reiter, F.
ED - Richter, S.
T1 - Florentine papyri under examination: The material study of the inks used at the beginning of the Common Era in the "Family of Kôm Kâssûm" Archive (Hermopolis)
N2 - Carbon inks with metallic admixtures are found on some papyri of the 2nd century CE from a family archive in Hermopolis. The great diversity of inks found in a single household within a short period of time suggests that inks were purchased rather than self-made.
KW - Carbon ink
KW - Iron-gall ink
KW - Mixed ink
KW - XRF ink analysis
KW - Family archives
KW - Hermopolis
PY - 2021
DO - https://doi.org/10.1515/apf-2021-0010
SN - 0066-6459
SN - 1867-1551
VL - 67
IS - 1
SP - 146
EP - 165
PB - De Gruyter
CY - Berlin
AN - OPUS4-53160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Wandtke, Karsten
A1 - Kannengießer, Thomas
T1 - Wire Arc Additive Manufacturing (WAAM) mit hochfesten Feinkornbaustählen
N2 - Die additive Verarbeitung hochfester Feinkornbaustähle mittels Wire Arc Additive Manufacturing (WAAM) ist ein komplexes, aber zugleich auch effizientes Verfahren, bei dem Werkstoff, Bauteilgeometrie und Schweißprozess gezielt aufeinander abgestimmt sein müssen. Ziel dieser Studie war es, einen Zusammenhang zwischen den Prozessparametern und der generierten Schichtgeometrie zu ermitteln. Dazu wurden definierte Referenzkörper mit einem robotergestützten Schweißsystem additiv gefertigt und hinsichtlich Schichthöhe, Wandstärke und Mikrostruktur analysiert. Fokus der Untersuchung waren sowohl konventionelle als auch für die WAAM-Fertigung speziell entwickelte hochfeste Schweißzusatzwerkstoffe. Die geometrischen Eigenschaften additiv gefertigter Bauteile lassen sich insbesondere durch die Faktoren Drahtvorschubgeschwindigkeit und Schweißgeschwindigkeit gezielt einstellen. Jedoch können diese Parameter nicht beliebig variiert werden, auch aufgrund der rheologischen Eigenschaften der Zusatzwerkstoffe. Zu hohe Streckenenergien führen zu lokalen Überhitzungen und Fehlstellen in der generierten Schicht. Undefinierte Fließ- und Erstarrungsvorgänge im überhitzten Bereich erschweren die maßhaltige Fertigung. Deshalb wird bei speziellen WAAM-Schweißdrähten das Fließverhalten gezielt modifiziert, sodass es über einen größeren Temperaturbereich hinweg konstant ist. Erst die Kenntnis über die komplexen Zusammenhänge zwischen den Prozessparametern und der Bauteilgeometrie ermöglicht die Erzeugung exakter Schichtmodelle für die additive Fertigung. Dies bildet die Grundlage für die Bearbeitung weiterer Fragestellungen auf dem Gebiet der additiven Fertigung mit hochfesten Zusatzwerkstoffen und insbesondere deren Anwendung in modernen hochfesten Bauteilen.
T2 - 41. Assistentenseminar Fügetechnik
CY - Magdeburg, Germany
DA - 03.09.2020
KW - MAG-Schweißen
KW - Eigenspannungen
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Kaltrisssicherheit
PY - 2021
SN - 978-3-96144-141-9
VL - 370
IS - 41
SP - 113
EP - 124
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-56641
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Challenges in repair welding of in-service h2-pipelines
N2 - Hydrogen will be one of the most important energy carriers of tomorrow. For the necessary large-scale and long-distance transportation, a reliable pipeline infrastructure is required. It is meanwhile in the most countries accepted to follow a two-way strategy by (I) repurposing the existing natural gas (NG) grid combined with (II) the installation of new pipelines. For example, in Europe a so-called European Hydrogen Backbone (EHB) is planned for 2040. Currently, 28 countries work together to establish a hydrogen pipeline grid of several thousands of kilometers. In that connection, a wide number of materials are used with different thicknesses, strength levels, chemical composition, surface conditions and so on. Worldwide research projects suggest the general compatibility of the currently applied pipeline steels e.g., in Germany the “SysWestH2” project. Nonetheless, the hydrogen gas grid will require regular inspections, repair, and maintenance. In addition, sometimes pipeline tees are required to connect new grids or pipelines the existing infrastructure. From that point of view, existing concepts from NG-grids must be investigated in terms of the transferability to hydrogen service. An overview on occurring challenges for this hydrogen transition, especially for in-service weld repair procedures is given in this presentation.
T2 - AMPP 2024 - The Association for Materials Protection and Performance
CY - Genoa, Italy
DA - 09.06.2024
KW - In-service
KW - Pipeline
KW - Repair welding
KW - High-pressure
KW - Hydrogen
PY - 2024
AN - OPUS4-60327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Phase Transformation and Strain Evolution during Welding of Low Transformation Temperature Alloys
N2 - In this work, the phase and strain formation in multipass welding of LTT gas metal arc welds were observed under realistic restraints by means of time resolved angular-dispersive synchrotron X-ray diffraction at the High Energy Materials Science beamline HEMS at PETRA III (DESY), Hamburg Germany. It was shown that the strain evolution during cooling correlates with the amount of martensite formed. Both, the strain of martensite and austenite are affected during phase transformation. Even though dilution processes limit the LTT effect in the root compared to the top layer, the strains are significantly reduced compared to the conventional weld metal. The observed effects are found for both Ni and Mn based LTT filler metals regardless of their respective Ms temperature.
T2 - 2nd International Conference on Advanced Joining Processes AJP 2021
CY - Sintra, Portugal
DA - 21.10.2021
KW - Welding
KW - Residual Stress
KW - In-situ diffraction
KW - Synchrotron
PY - 2021
AN - OPUS4-53609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Residual Stress Analysis on a DED-Arc High-strength Steel Component Using the Contour Method
N2 - This poster compares the results of the residual stress determination of DED-Arc open hollow cuboid specimens via XRD with the contour method. The results are in very good agreement.
T2 - ECRS11
CY - Prague, Czech Republic
DA - 03.06.2024
KW - DED-Arc
KW - Residual stress
KW - Contour method
PY - 2024
AN - OPUS4-60221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Component test for the assessment of hydrogen assisted cracking susceptibility of thick-walled submerged arc welded offshore steels
N2 - Offshore wind turbines (OWT) are a key factor of the sustainable energy generation of tomorrow. The continuously increasing installation depths and weight of the OWTs require suitable foundation concepts like monopiles or tripods. Typically, mild steels like the S420ML are used with plate thicknesses up to several hundreds of mm causing high restraints in the weld joints. Due to the large plate thickness, submerged arc welding (SAW) with multiple wires is the state-of-the-art welding procedure. As a result of the very high stiffness of the construction, a certain susceptibility for time-delayed hydrogen-assisted cracking (HAC) may occur. The evaluation of crack susceptibility is very complex due to the component size and stiffness of real offshore structures. For this purpose, a near-component test geometry was developed to transfer the real stiffness conditions to laboratory (i.e., workshop) scale. The investigated mock-up, weighing 350 kg, comprised heavy plates (thickness 50 mm, seam length 1,000 m) joined by a 22-pass submerged arc weld. Additional stiffeners simulated the effect of high restraint or shrinkage restraint of the weld. Extreme scenarios of hydrogen absorption during welding were simulated via the use of welding fluxes in dry (HD < 5 ml/100g Fe) and moisture condition (HD > 15 ml/100g Fe). The residual stresses were determined by a robot X-ray diffractometer. Areas of critical tensile residual stress (at the level of the yield strength) were found in the weld metal and heat affected zone. To identify possible delayed cracking, the welds were tested by phased array ultrasonic testing (PAUT) after 48 h. Summarized, no significant occurrence of HAC was detected, indicating the high crack resistance of the welded joint, i.e., a suitable combination of base material, welding consumable and welding parameters.
T2 - AJP 2023: 3rd International Conference on Advanced Joining Processes 2023
CY - Braga, Portugal
DA - 19.10.2023
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - Component test
KW - NDT
KW - Waiting time
PY - 2023
AN - OPUS4-58672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Residual Stress Evolution During Slot Milling for Repair Welding and WAAM of High-Strength Steel Components
N2 - High-strength steels have great potential for weight optimization due to reduced wall thicknesses in many modern steel constructions. Further advances in efficiency can be achieved through the application of additive manufacturing processes, such as Wire Arc Additive Manufacturing (WAAM). These technologies enable the sustainable and resource-efficient manufacturing of high-strength steels into near-net-shape, efficient structures. During the production of steel structures, unacceptable defects may occur in the weld area or in the WAAM component, e.g., due to unstable process conditions. The economical solution for most of the cases is local gouging or machining of the affected areas and repair welding. With respect to the limited ductility of high-strength steels, it is necessary to clarify the effects of machining steps on the multiaxial stress state and the high design-induced shrinkage restraint. In this context, the component-related investigations in two research projects are concerned with the residual stress evolution during welding and slot milling of welds and WAAM structures made of high-strength steels with yield strengths ≥790 MPa. In-situ digital image correlation (DIC) and ex-situ X-ray diffraction (XRD) were used to analyse the stresses and strains induced on specimens during and after milling. The systematic analyses revealed a significant interaction of the stiffness and relaxation of the specimens with the initial residual stresses induced by welding.
T2 - ICRS 11 - The 11th International Conference on Residual Stresse
CY - Nancy, France
DA - 27.03.2022
KW - MAG-Schweißen
KW - Eigenspannungen
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Reparaturschweißen
KW - Gefügedegradation
KW - Windenergie
PY - 2022
AN - OPUS4-56708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Konstruktive Einflüsse bei der beanspruchungsgerechten Reparatur geschweißter Bauteile aus hochfesten Feinkornbaustählen
N2 - Für eine nachhaltige und ressourceneffiziente Fertigung von Windkraftanlagen ist der Einsatz moderner hochfester Feinkornbaustähle vielfach notwendig. Bei der Montage hochfester Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich. Derzeitige Normen und Verarbeitungsrichtlinien geben hierbei kaum Informationen zu adäquaten Reparaturkonzepten, insbesondere für hochfeste Stähle. Vor diesem Hintergrund werden an der Bundesanstalt für Materialforschung und -prüfung (BAM) bauteilrelevante Untersuchungen zu den schweißbedingten Beanspruchungen und Gefügeveränderungen bei der schweißtechnischen Reparatur durch lokales thermisches Ausfugen und erneutes Schweißen durchgeführt.
Hierzu werden einige wesentliche Ergebnisse an Beispielen des Ingenieurbaus, mit Blick auf die mechanisch-technologischen Eigenschaften und Eigenspannungen erörtert. In einem aktuellen Vorhaben (FOSTA P1311, IGF 20162N) sind darauf aufbauend die Einflüsse durch die Schrumpfbehinderung und Wärmeführung beim Reparaturschweißen hochfester Feinkornbaustähle (S500MLO, S960QL) sowie die Reparaturzyklenanzahl Fokus systematischer Untersuchungen. Mittels strukturmechanischer Berechnungen ließen sich hierzu selbstbeanspruchende Probenformen identifizieren, die unterschiedliche definierte Steifigkeitsverhältnisse von Reparaturschweißnähten realer Bauteile abbilden. Schweißnähte an diesen bauteilähnlichen Proben weisen signifikant erhöhte schweißbedingte Beanspruchungen mit zunehmenden (Biege-)Einspanngraden auf. Im Vergleich mit bisherigen Erkenntnissen wird gezeigt, dass eine sichere Reparatur solcher Schweißnähte nur mittels optimaler Reparaturkonzepte und Wärmeführung gelingt, um diesen hohen Beanspruchungen und auch den speziellen Gefügen hochfester Stähle Rechnung zu tragen.
Ziel der Untersuchungen ist es letztlich, Empfehlungen für beanspruchungs- und werkstoffgerechte Reparaturkonzepte gerade für KMU abzuleiten, um Schäden und zumeist teure Nacharbeiten zu vermeiden.
T2 - 4. Niedersächsisches Symposium Materialtechnik
CY - Online meeting
DA - 25.02.2021
KW - Feinkornbaustähle
KW - Hochfest
KW - Reparaturschweißen
KW - Eigenspannungen
PY - 2021
AN - OPUS4-52562
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Analysen zur Beeinflussung von Gefüge und Fertigungsbeanspruchungen bei der Generation, Reparatur und Bearbeitung hochbelasteter Komponenten Kurzvorstellung des DVS Vorhabens 1.3211 (20.979N)
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die ersten Ergebnisse der Mikrostruktur sowie der Härte der via PTA gefertigten Probenkörper des CoCr-Werkstoffes und den ersten Modifizierungen werden vorgestellt. Darüber hinaus wird ein Ausblick auf die folgenden Arbeiten gegeben.
T2 - Gemeinschaftssitzung DIN/DVS NAS 092-00-05 GA "Zerstörende Prüfung von Schweißverbindungen"
CY - Online meeting
DA - 10.03.2021
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Plasma-Pulver-Auftragschweißen
KW - Schweißzusatzmodifikation
KW - Schlichtfräsen
PY - 2021
AN - OPUS4-52352
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dudek, Gabriele
T1 - Klassifizierung von Feuerwerk in Metallkäfigen
N2 - Die Untersuchungen richten sich auf Verbundfeuerwerk und Feuerwerksbatterien, welche mit Zwischenverpackungen, bestehend aus Metallkäfigen und Metallbändern, für den Transport versehen wurden. Es wird gezeigt, wie sich diese Zwischenverpackungen auf unterschiedliche Feuerwerksartikel auswirken können und welche Klassifizierungen resultieren. Es wurde beobachtet, dass die Wirkung der Metallkäfige bei bestimmten Konstellationen äußerst nachteilig ist und eine Massenexplosion befördern kann.
T2 - BGRCI Erfahrungsaustausch „Explosivstoff-Industrie“ 2022 Sachgebiet „Explosionsgefährliche Stoffe“
CY - Bremerhaven, Germany
DA - 22.09.2022
KW - Lagergruppenzuordnung
KW - Feuerwerk
KW - Pyrotechnik
KW - Transportklassifizierung
PY - 2022
AN - OPUS4-55785
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dudek, Gabriele
T1 - Classification of fireworks in metal wire cages
N2 - Classification tests (UN 6a and 6c) of firework batteries and composite fireworks in metal wire cages were presented. The cages are intended to be used during transport to prevent the occurrence of projections in the event of a fire. However, the results of this investigation showed that, particularly in the case of articles with whistle effects packed in this way, confinement phenomena occurred that lead to mass explosions and must be considered in future classification.
T2 - International Group of experts on the explosion risks of Unstable Substances (IGUS)- Joint Meeting CIE/IGUS-EPP
CY - Madrid, Spain
DA - 17.04.2023
KW - Feuerwerk
KW - Pyrotechnik
KW - Transportklassifizierung
KW - Lagergruppenzuordnung
PY - 2023
AN - OPUS4-57388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Agasty, Amit
T1 - Application of underwater tests to determine he-equivalents of pyrotechnic substances
N2 - A technical-safety evaluation of the detonation effects of pyrotechnic compositions can be performed on the basis of TNT/PETN equivalence. The equivalence determination can be carried out by characterization of the blast wave generated because of detonation in free field tests, which however can be highly resource intensive and prone to uncertainties. Here, we present underwater ‘small-scale’ experiments for the determination of such equivalents.
Underwater experiments, as described in the European standard EN 13763-15:2004, are performed to test the capability of detonators to initiate secondary explosives by determining the released energy. At BAM this test was modified to compare the energy output of the pyrotechnic mixtures (those used in air bag gas generators and firework flash compositions) and thus to determine their equivalents of high explosives like TNT or PETN. In the modified tests, small cylindrical copper containers were filled with pyrotechnic substances, which were then attached to standard detonators. This explosive charge assembly was then lowered into a water tank of about 1000 l capacity. At the same depth as the charge assembly, a piezoelectric pressure sensor was immersed in the water at a horizontal distance of about 400 mm from the charge. By recording the time-dependent pressure during the test, the shock energy as well as the energy associated with the expanding gas bubble were determined.
T2 - 26th International Symposium on Military Aspects of Blast and Shock (MABS26)
CY - Wollongong, Australia
DA - 03.12.2023
KW - Underwater Tests
KW - TNT/PETN - Equivalent
PY - 2023
AN - OPUS4-58928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - Researching automation of gypsum recycling
N2 - This poster illustrates first successful experiments of recycling gypsum in hypersaline solutions with quantification via Raman-spectroscopy. To furhter enhancements include an automation setup, that was developed to gain in-situ measurements and open a pathway for batch-conversions and upscaling.
T2 - BESSY@HZB User Meeting
CY - Berlin, Germany
DA - 12.12.2024
KW - Recycling
KW - Gypsum
KW - Raman-spectroscopy
KW - Automation
PY - 2024
AN - OPUS4-62292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Common Strategies for Advancing the Digital Transformation in Materials Science
N2 - Materials science and engineering is inherently interdisciplinary, bridging the natural sciences and engineering domains. This diversity is reflected in its digitalisation efforts, where subdomains often define distinct data structures, taxonomies, and terminologies. As a result, semantic ambiguities and fragmented research data management remain major obstacles to data integration across the field.
Recent advances in AI underscore the role of data as a strategic resource for innovation. However, the effectiveness of these methods depends on the availability, completeness, and quality of data. Well-structured and semantically annotated materials and process data that is processed and stored using semantic technologies, for example, can enable breakthroughs, particularly at the interface of processing, structure, properties, and performance. A systematic, coordinated approach grounded in the FAIR guiding principles and lifecycle-oriented data management is therefore essential.
The German MaterialDigital Initiative, funded by the Federal Ministry of Education and Research, exemplifies such a collaborative framework. It brings together diverse project consortia, fostering community-driven consensus through exchange forums like the Ontology Playground, and supporting harmonized solutions for semantic interoperability.
By strengthening data culture and semantic infrastructure, collaborative digitalisation initiatives offer a scalable path to accelerated materials development and reproducible scientific progress paving the way for more efficient, data-driven innovation in materials science and engineering.
T2 - The 4th International Symposium for Materials R&D Data
CY - Tsukuba, Japan
DA - 17.07.2025
KW - FAIR Research Data Management
KW - Community Building
KW - Semantic Web Technologies
PY - 2025
AN - OPUS4-63741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Ergebnisse des Ringversuchs zur Integration der DIN 55635 in die DIN 50937
N2 - Die Präsentation zeigt die Motivation und die Ergebnisse des Ringversuchs gemäß DIN 55635 an Zinkblechen. Die dort bestimmten Abtragsraten dienen der Aufnahme der DIN 55635 in die Vergleichsnorm 50937.
T2 - Sitzung des Normausschusses NA 062-01-77 AA
CY - Online meeting
DA - 28.10.2020
KW - Korrosion
KW - Korrosionswechselprüfung
KW - Zink
KW - Stahl
KW - Normung
PY - 2020
AN - OPUS4-51481
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Ergebnisse des Ringversuchs zur Integration der DIN 55635 in die DIN 50937
N2 - Die Präsentation stellt die Hintergründe und die Ergebnisse des Ringversuchs zur DIN 55635 an Reinzinkblechen vor. Die Ergebenisse dienen der Aufnahme der DIN 55635 in die Vergleichnorm DIN 50937.
T2 - Sitzung des Normausschusses NA 062-01-71 AA
CY - Online meeting
DA - 27.10.2020
KW - Korrosion
KW - Korrosionswechselprüfung
KW - Zink
KW - Stahl
KW - Normung
PY - 2020
AN - OPUS4-51480
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Nichtrostende Stähle - Passivität ist naturgemäß aber unter welchen Bedingungen stabil ?
N2 - Der Vortrag behandelt die Passivität von nichtrostenden Stählen. Es werden Ausführungen zur Passivschichtbildung und deren Kinetik gemacht. Weiterhin werden lokale Korrosionsarten näher erläutert und deren Mechanismen erklärt. An praktischen Beispielen werden inner und äussere Einflussfaktoren auf die Passivität und Korrosionsbeständigkeit von nichtrostenden Stählen näher beleuchtet und erklärt.
T2 - fkks infotag 2021
CY - Online meeting
DA - 14.01.2021
KW - Korrosion
KW - Passivität
KW - Nichtrostender Stahl
KW - Lochkorrosion
KW - Spaltkorrosion
PY - 2021
AN - OPUS4-52008
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Ergebnisse des Ringversuchs zur Integration der DIN 55635 in die DIN 50937
N2 - Die Präsentation zeigt die Motivation und die Ergebnisse des Ringversuchs gemäß DIN 55635 an Zinkblechen. Die dort bestimmten Abtragsraten dienen der Aufnahme der DIN 55635 in die Vergleichsnorm 50937.
T2 - Sitzung der Ad-hoc Gruppe "Ringversuch DIN 55635"
CY - Online meeting
DA - 15.12.2020
KW - Korrosion
KW - Klimawechseltest
KW - Zink
KW - Korrosionsprüfung
PY - 2020
AN - OPUS4-51864
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Korrosion und Korrosionsschutzverfahren Teil 2: Korrosionsschutzverfahren
N2 - Dieser Vortrag erläutert die verschiedenen Korrosionsschutzmethoden, welche sich aus den grundlegendem Verständnis der Korrosion ableiten lassen. So werden korrosionsschutzgerechte Kontruktionen, die Asuwahl geeigneter Werkstoffe und die Vermeidung von galvanischen Elementen erläutert. Unterstützt werden die verschiedenen Themengebiete mit Praxisbeispielen.
T2 - TAE Seminar Kathodischer Korrosionsschutz - Grundlagenkurs für erdverlegte Anlagen, Stahlbeton und Innenschutz
CY - Online meeting
DA - 09.02.2021
KW - Korrosion
KW - Korrosionsschutz
KW - Beschichtung
KW - Überzüge
KW - Passivität
PY - 2021
AN - OPUS4-52103
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Korrosion und Korrosionsschutzverfahren Teil 1: Korrosion metallener Werkstoffe
N2 - Dieser Vortrag behandelt die Grundlagen der Korrosion metallener Werkstoffe. Es wird die Triebkraft der Korrosion, die Teilreaktionen sowie die messtechnische Bestimmung der Korrosionsgeschwindigkeit beschrieben. Weiterhin werden Korrosionselemente wie Konzentrationselemente und Bimetallkorrosion näher erläutert.
T2 - TAE Seminar Kathodischer Korrosionsschutz - Grundlagenkurs für erdverlegte Anlagen, Stahlbeton und Innenschutz
CY - Online meeting
DA - 09.02.2021
KW - Korrosion
KW - Metallene Werkstoffe
KW - Korrosionselemente
KW - Bimetallkorrosion
KW - Korrosionsschutz
PY - 2021
AN - OPUS4-52102
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tielemann, Christopher
A1 - Busch, R.
A1 - Reinsch, Stefan
A1 - Patzig, C.
A1 - Höche, T.
A1 - Avramov, I.
A1 - Müller, Ralf
T1 - Oriented surface nucleation in diopside glass
N2 - Es wird die Texturbildung in kristallisierendem Diopsidglas im Zusammenhang mit der Oberflächenbeschaffenheit der unbehandelten Probe untersucht. Zudem wird der diskutiert, dass es sich bei der Texturbildung in Gläsern höchstwahrscheinlich um ein Nukleationsphänomen handelt welches auf die richtungsabhängige Grenzflächenenergie der kristallisierenden Phase zurückzuführen ist.
N2 - Oriented surface crystallization on polished diopside glass surfaces has been studied with scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy and laser scanning microscopy.
An orientation preference of [001] parallel to the glass surface was detected for separately growing diopside crystals even as small as 700 nm in size. This finding shows that crystal orientation occurs in the outermost surface layer without crystal-crystal interaction and indicates that the crystal orientation is a result of oriented nucleation. Depending on surface preparation, monomodal crystal orientation distributions with [100] perpendicular to the surface or bimodal distributions with [100] and [010] perpendicular to the glass Surface were detected. It was also shown that the degree of crystal orientation increases with decreasing Surface roughness. The observed orientation of diopside crystals could be explained in terms of the interfacial energies of different crystal faces.
KW - Surface energy
KW - Glass ceramic
KW - Glass
KW - EBSD
KW - Diopsid
PY - 2021
UR - https://www.sciencedirect.com/science/article/pii/S002230932100020X
DO - https://doi.org/10.1016/j.jnoncrysol.2021.120661
SN - 0022-3093
VL - 562
PB - Elsevier B.V.
AN - OPUS4-53073
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Reinsch, Stefan
A1 - Rouxel, T.
A1 - Behrens, H.
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Vacuum crack growth in alkali silicate glasses
N2 - Crack growth velocity in alkali silicate glasses was measured in vacuum across 10 orders of magnitude with double cantilever beam technique. Measured and literature crack growth data were compared with calculated intrinsic fracture toughness data obtained from Young´s moduli and the theoretical fracture surface energy estimated from chemical bond energies. Data analysis reveals significant deviations from this intrinsic brittle fracture behavior. These deviations do not follow simple compositional trends. Two opposing processes may explain this finding: a decrease in the apparent fracture surface energy due to stress-induced chemical changes at the crack tip and its increase due to energy dissipation during fracture.
KW - Silicate glass
KW - Brittle fracture
KW - Crack growth
KW - Calculated intrinsic fracture toughness
PY - 2021
DO - https://doi.org/10.1016/j.jnoncrysol.2021.121094
SN - 0022-3093
VL - 572
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - Sintering and Foaming of Silicate Glass Powders
N2 - The lecture focuses on the mechanisms of non-desired gas bubble formation and foaming during the sintering of glass powder compacts. It is shown that foaming is driven by carbon gases and that carbonates, encapsulated in micropores or mechaniacally dissolved beneath the glass surface, provide the major foaming source.
T2 - Sandanski Workshop Sinter crystallization 27th-29th September 2021 PROJECT “THEORY AND APPLICATIONS OF SINTER-CYSTALLIZATION” DN 19/7
CY - Online meeting
DA - 27.10. 2021
KW - Sintering
KW - Non-desired foaming
PY - 2021
AN - OPUS4-53772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Kurzbericht aus den DIN Ausschüssen
N2 - Der Vortrag gibt einen Überblick über die Tätigkeiten der DIN-Ausschüsse "Korrosionsprüfverfahren" sowie "Korrosion und Korrosionsschutz". Es werden neuste Informationen zum Stand verschiedener Normen aus den beiden Ausschüssen gegeben.
T2 - Arbeitskreissitzung des GfKorr-Arbeitskreises Korrosionsuntersuchung und -überwachung
CY - Online meeting
DA - 08.12.2021
KW - Korrosion
KW - Korrosionsschutz
PY - 2021
AN - OPUS4-54085
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Bedingungen für den schadensfreien Einsatz von nichtrostenden Stählen
N2 - Unter Passivität versteht man den Korrosionsschutz durch dünne, festhaftende Schichten aus Korrosionsprodukten. Für den schadensfreien Einsatz nichtrostender Stähle ergeben sich daraus zwei grundsätzliche Anforderungen.
Erstens muss sich die Passivschicht vollständig ausbilden können. Dabei sind die Oberflächenausführung, die mechanische Bearbeitung, die Elementverteilung, Ausscheidungen, die Wärmeeinbringung z.B. bei der schweißtechnischen Verarbeitung, Anlauffarben, sowie die chemische Nachbehandlung bzw. Konditionierung der Oberflächen von großer Bedeutung. Zweitens muss die Repassivierung von Defektstellen unter den Einsatzbedingungen möglich sein. Für das Repassivierungsvermögen sind die Legierungszusammensetzung, mögliche kritische Betriebszustände, prozessbedingte Besonderheiten, wie etwa Stagnationsbedingungen und Reinigungsprozesse von Bedeutung.
T2 - Nichrostende Stähle - Eigenschaften und Anwendung
CY - Düsseldorf, Germany
DA - 01.06.2022
KW - Korrosion
KW - Werkstoffauswahl
KW - Dauerhaftigkeit
PY - 2022
AN - OPUS4-54989
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blaeß, Carsten
T1 - 3D printing of crystallizing bioactive glasses
N2 - Artificial bone replacement by individual customized three-dimensional resorbable bioactive glass has not yet been widely established in the clinical use. This is mainly due to the antagonism of sintering ability and suitable bioactivity. Competitive crystallization often prevents the generation of dense sintered bodies, especially for additive manufactured 3D structures. Previous studies of the fluoride-containing glass F3 have shown its potential to combine both sintering ability and suitable bioactivity. Furthermore, the occurring sintering blockade by surface crystallization of Na2CaSi2O6 was tunable by glass particle size.
In this study the glasses F3, F3-Cu with 1 mol% CuO added at the expense of CaO and the well-known 13-93 were chosen to determine the influence of surface crystallization on 3D printed sinter bodies. For this purpose, grain size fractions in range of smaller 32 µm to 315 µm in fraction size of 6-20 µm were sieved from jaw crushed glass frit as well as glass cubes were cut from casted blocks for all glasses. Sintering behavior of both pressed and printed powder compacts was observed via heating microscopy. Crystallization was determined by DTA and crystallization progress was monitored on fractured sinter bodies and polished cubes via electron and laser scanning microscopy as well as with diffractometry.
Depending on grain size the formation of crystalline support framework along former grain boundaries shows the capability to stabilize fully densified sinter bodies before softening. Beside of this, the generation of complex hierarchic porosity was possible as well.
T2 - ICG Berlin 2022
CY - Berlin, Germany
DA - 03.07.2022
KW - Bioactive Glass
KW - Crystallization
KW - Sintering
KW - 3D printing
PY - 2022
AN - OPUS4-55253
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Field exposure studies under sheltered and unsheltered conditions at different test sites in northern and eastern Germany: Update after 5 years of exposure
N2 - A series of field exposure tests according to ISO 9223 up to 9226 was carried out at different locations to determine the corrosivity and the corrosion progress of different test sites throughout northern and eastern Germany. Standard test specimens of steel, zinc, copper and aluminium were exposed to rural, city and marine atmosphere at test sites of the Bundesanstalt für Materialforschung und -prüfung (BAM). Test sites at city atmosphere comprised exposure on a rooftop, next to a highly frequented road and directly at a motorway. Exposure under marine conditions was carried out at Heligoland in the North Sea. The specimens were stored under sheltered and unsheltered conditions on each test site, respectively. Corrosion rates after the first year of field exposure were determined and used for the classification of the atmospheres and the test sites regarding the corrosivity category.
Results after the first year of exposure were presented at the EUROCORR 2018 in Cracow. The current presentation will present an update of results of the systematic study after five years of exposure. The corrosion progress and the mass loss of the standard metals steel, zinc, copper and aluminium will be presented and discussed with respect to the atmospheric conditions and the time of wetness at the test sites. In addition, the difference between sheltered and unsheltered conditions will be discussed.
T2 - EUROCORR 2022
CY - Berlin, Germany
DA - 28.08.2022
KW - Atmospheric Corrosion
KW - Atmosphärische Korrosion
KW - Korrosionsuntersuchungen
KW - Corrosion testing
PY - 2022
AN - OPUS4-55602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reinsch, Stefan
T1 - Surface-Initiated Microstructure Formation in Glass Ceramics
N2 - Up to now, oriented surface crystallization phenomena are discussed controversially, and related studies are restricted to few glasses. For silicate glasses we found a good correlation between the calculated surface energy of crystal faces and oriented surface nucleation. Surface energies were estimated assuming that crystal surfaces resemble minimum energy crack paths along the given crystal plane. This concept was successfully applied by Rouxel in calculating fracture surface energies of glasses. Several oriented nucleation phenomena can be herby explained assuming that high energy crystal surfaces tend to be wetted by the melt. This would minimize the total interfacial energy of the nucleus. Furthermore, we will discuss the evolution of the microstructure and its effect on the preferred crystal orientation.
T2 - 26th International Congress on Glass
CY - Berlin, Germany
DA - 03.07.2022
KW - Glass
KW - Oriented surface crystallization
KW - Surface energy
KW - Bond energy
KW - Nucleation mode
PY - 2022
AN - OPUS4-56070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tielemann, Christopher
T1 - Oriented Surface Crystallization
N2 - Up to now, oriented surface crystallization phenomena are discussed controversially, and related studies are restricted to few glasses. For silicate glasses we found a good correlation between the calculated surface energy of crystal faces and oriented surface nucleation. Surface energies were estimated assuming that crystal surfaces resemble minimum energy crack paths along the given crystal plane. This concept was successfully applied by Rouxel in calculating fracture surface energies of glasses. Several oriented nucleation phenomena can be herby explained assuming that high energy crystal surfaces tend to be wetted by the melt. This would minimize the total interfacial energy of the nucleus. Furthermore, we will discuss the evolution of the microstructure and its effect on the preferred crystal orientation.
T2 - 26th International Congress on Glass
CY - Berlin, Germany
DA - 03.07.2022
KW - Glass
KW - Surface energy
KW - Crystal orientation
PY - 2022
AN - OPUS4-56074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Sinn und Unsinn der Wirksumme bei Nichtrostenden Stählen
N2 - Anhand der Wirksumme ist eine Abschätzung des legierungsabhängigen Einflusses auf den Korrosionswiderstand gegen chloridhaltige Medien möglich. Die berechneten Werte sind nur bei optimaler Wärmebehandlung und Verarbeitung zutreffend.
Die Anwendung einer einfachen Formel unter Berücksichtigung von Chrom, Molybdän und Stickstoff ist in der Regel völlig ausreichend. Das daraus abgeleitete Ranking von Werkstoffen ist für diverse technische Regelwerke und zur Unterstützung der Werkstoffauswahl geeignet.
Für die Warenein-/Ausgangskontrolle ist die alleinige Feststellung der Wirksumme unzureichend. Ergänzende Korrosionsuntersuchungen/-prüfungen zur Beschreibung des Korrosionswiderstandes sind dafür notwendig. Gleiches gilt für die Beurteilung von Schadensfällen. Hier sind Verarbeitung, Einsatzbedingungen und die Konstruktion von ausschlaggebender Bedeutung.
T2 - fkks Infotag: Charakteristische Kennwerte zur Einschätzung des Korrosionsschutzes
CY - Online meeting
DA - 12.01.2023
KW - Wirksumme
KW - Korrosion
KW - Nichtrostende Stähle
PY - 2023
AN - OPUS4-56821
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - Vacuum crack growth in silicate glasses
N2 - Although the slow crack growth in glass is dominated by stress-corrosion phenomena, it also should reflect the underlaying intrinsic fracture behavior controlled by glass chemistry and structure. To investigate such underlaying phenomena, crack growth velocity in alkali silicate glasses was measured in vacuum across 10 orders of magnitude with double cantilever beam technique. Measured and literature crack growth data were compared with calculated intrinsic fracture toughness data obtained from Young’s moduli and theoretical fracture surface energy. Data analysis reveals slight correlation with the packing density and significant deviations from the intrinsic brittle fracture behavior. These deviations do not follow simple compositional trends. Two opposing processes may explain this finding: a decrease in the apparent fracture surface energy due to stress-induced chemical changes at the crack tip and its increase due to energy dissipation during fracture.
T2 - 26th International Congress on Glass
CY - Berlin, Germany
DA - 03.07.2022
KW - Oxide glass
KW - Fracture toughness
KW - Fracture surface
PY - 2022
AN - OPUS4-56485
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
A1 - Reinsch, Stefan
A1 - Müller, Ralf
A1 - Chen, Y.-F.
A1 - Contreras Jaimes, A.
T1 - Datengetriebener Workflow für die beschleunigte Entwicklung von Glas (GlasDigital)
N2 - Das Projekt GlasDigital wurde im allgemeinen vorgestellt, sowie die einzelnen Zwischenstände der verschiedenen Arbeitspakete aller Projektpartner präsentiert. Die allgemeine Porjektvorstellung ist auf deutsch. Die Zwischenstände der Arbeitsinhalte sind auf englisch.
T2 - PMD Vollversammlung
CY - Berlin, Germany
DA - 03.11.2022
KW - Oxidglas
KW - Robotische Glasschmelzanlage
KW - ML
KW - Ontologie
KW - Digitaler Zwilling
KW - Bildanalyse
PY - 2022
AN - OPUS4-56491
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Mehr als Chrom-Nickel - Alternative nichtrostende Stähle und ihre Anwendungspotentiale
N2 - In diesem Vortrag werden die Hintergründe, Ziele und ausgewählte Ergebnisse aus dem IGF-Vorhaben zu Korrosionsuntersuchungen an alternativen nichtrostenden Stählen vorgestellt. Weiterhin werden die Vorteile dieser Stähle hinsichtlich mechanisch -technologischer Eigenschaften sowie deren Kosten gegenüber den klassischen austenitischen nichtrostenden Stählen aufgezeigt.
T2 - GfKORR Jahrestagung 2022
CY - Frankfurt am Main, Germany
DA - 08.11.2022
KW - Korrosion
KW - Nichtrostende Stähle
KW - Duplexstähle
KW - Lochkorrosion
KW - Festigkeit
PY - 2022
AN - OPUS4-56197
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kilo, M.
T1 - Glass Screening for the systematic development of new glasses
N2 - Die technischen Möglichkeiten der robotischen Glasschmelzanlage der BAM werden vorgestellt.
T2 - 26th International Conference on Glass
CY - Berlin, Germany
DA - 04.07.2022
KW - Material Digital
PY - 2022
AN - OPUS4-56280
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waurischk, Tina
T1 - Data-driven Workflow for Accelerated Glass Development (GlasDigital)
N2 - As part of a joint project involving the Fraunhofer Institute for Silicate Research (ISC), the Friedrich Schiller University of Jena, the Clausthal University of Technology and the Federal Institute for Materials Research and Testing (BAM), digital tools are to be created for the development of new types of glass materials. Current processes for the production of glasses with improved properties are usually very cost- and energy-intensive due to the low degree of automation and are subject to long development cycles. The use of robotic synthesis processes in combination with self-learning machines is intended to overcome these problems in the long term. The development of new types of glass can then not only be accelerated considerably, but also be achieved with much less effort.
In this talk, data generation via a robotic high-throughput glass melting system is presented, which should be the experimental basis for the ontology developed within the project GlasDigital.
T2 - Materials Science and Engineering Congress (MSE 2022)
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Oxidglas
KW - Robotische Glasschmelzanlage
PY - 2022
AN - OPUS4-56489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Korrosionsarten an geschweißten Bauteilen aus Cr-Ni-Stahl
N2 - Die Bedingungen für den schadensfreien Einsatz nichtrostender Stähle, nicht nur bei Schweißverbindungen, sind:
1) Die Passivschicht muss sich vollständig ausbilden können.
Voraussetzung dafür sind glatte, blanke, saubere Oberfläche, eine gleichmäßige Elementverteilung, wenig Ausscheidungen und Verunreinigungen. Eine mögliche Beeinflussung der Gefügeausbildung durch Warmumformung und durch die
schweißtechnische Verarbeitung sind zu beachten. Anlauffarben
müssen durch geeignete geeignete chemische bzw. mechanische Nachbehandlung entfernt werden.
2) Die Repassivierung von Defektstellen unter Einsatzbedingungen muss möglich sein, was durch geeignete Werkstoffauswahl und die Legierungszusammensetzung sicherzustellen ist. Unplanmäßige Betriebszustände oder Störungen können kritische Systemzustände hervorrufen, die die Repassivierung beeinträchtigen oder verhindern.
Eine geeignete Unterhaltsreinigung ist sicherzustellen.
T2 - Weiterbildung DVS Bezirksverband Chiemgau
CY - Trostberg, Germany
DA - 02.03.2023
KW - Nichtrostender Stahl
KW - Korrosionsverhalten
KW - Verarbeitung
KW - Fehlerquellen
PY - 2023
AN - OPUS4-57150
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Projektvorstellung Gefügeveränderung bei trockener Schleifbearbeitung
N2 - Der Vortrag stellt die Projektskizze zum Thema Gefügeveränderung bei trockener Schleifbearbeitung vor. Das Projekt hat das Ziel, das sich aus dem Trockenschleifverfahren ergebende chemische, mechanische und thermische Belastungskollektiv in der Kontaktzone zwischen Schleifmittel und Stahloberfläche in Abhängigkeit der verwendeten Schleifparameter genau zu beschreiben und die daraus resultierenden Oberflächen- und Gefügeveränderungen zu identifizieren und zu klassifizieren.
T2 - Jahrestagung der Forschungsgemeinschaft Schleifen (FGS) 2023
CY - Würzburg, Germany
DA - 30.03.2023
KW - Korrosion
KW - Trockenschleifen
KW - Mikrostruktur
KW - Stahl
KW - Nichtrostender Stahl
PY - 2023
AN - OPUS4-57256
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosenbusch, Ivo
A1 - Arai, Marylyn Setsuko
A1 - Rizzo, Fabio
A1 - de Camargo, Andrea S. S.
A1 - Ravoo, Bart Jan
T1 - A host–guest approach to ratiometric pH sensing using upconversion nanoparticles
N2 - A new pH nanosensor based on β-NaYF4:Yb3+/Tm3+ upconversion nanoparticles functionalized with cyclodextrin and a pH-sensitive adamantane-modified nitrobenzoxadiazole dye (NBD-Ad).
KW - Host-guest materials
KW - Upconversion nanoparticles
KW - Ratiometric optical sensors
KW - pH sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637722
DO - https://doi.org/10.1039/d5na00145e
SN - 2516-0230
VL - 7
IS - 13
SP - 4142
EP - 4151
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Optical and Spectroscopic Properties of Glasses
N2 - Optical glasses have given us the eyes to unveil the microscopic and the macroscopic worlds through microscope and telescope lenses, they have revolutionized the way we communicate through fiber optics and portable device screens, as well as given us new perspectives for sustainable energy harvesting conversion and generation. To meet the demands of ever-growing markets, the compositional design of new glasses requires full characterization of thermal, mechanical, electric, and optical properties. Particularly, the characterization of optical properties is not only relevant for optical/luminescent applications but is also essential for the tailored design of some medical and dental materials such as restorative resins, implants and prothesis. In this seminar we will introduce the fundaments on the optical properties of materials, with particular focus on glasses, and the techniques to characterize them.
T2 - 3rd Sao Carlos School on Glasses and Glass-Ceramics
CY - Sao Carlos, Brazil
DA - 10.03.2025
KW - Optical properties
KW - Glasses
PY - 2025
AN - OPUS4-63773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea Simone Stucchi
T1 - Structure and photophysics of RE ion doped gallium phosphofluoride glasses containing silver nanostructures: Effects of heat treatment and femtosecond direct laser writing.
N2 - Gallium fluoride phosphate glasses are interesting hosts for emissive rare-earth (RE) dopants. Despite featuring low refractive index, they present high energy radiation resistance and a wide optical transmission range (350 to 1700 nm) enabling observation of important RE3+ emissions in the visible to near-infrared spectral range. In a previous, NMR-based structural study of the system xGa(PO3)3–(40-x)GaF3–20BaF2–20ZnF2–20SrF2 (x = 5 - 25 mol%), we verified that the network structure of these glasses is dominated by P-O-Ga linkages with no P-O-P linkages and that Ga is mainly six-coordinated in a mixed fluoride/phosphate environment. For Eu3+ doped samples, the photophysical properties strongly suggest changes in the ion´s ligand distribution toward a fluoride-dominated environment at low P/F, which translates into improved radiative emissions. To extend the studies to other RE doped glasses, and glasses containing Ag nanostructures (and their influence on RE emission), we selected the composition 25Ga(PO3)3 – 20ZnF2 – 30BaF2 - (25 – x - y)SrF2 – xAgNO3 - yNdF3, where x = 0, 1, 3, 5, 10 mol% and y = 0 or 1 mol%. The glasses were synthesized through the conventional melt-quenching technique and fully characterized from the thermal, structural, and microstructural viewpoints. By appropriate heat-treatment, the presence of both Ag nanoclusters (Ag-NCs, < 10 nm) and larger nanoparticles was confirmed by TEM in agreement with the observation of broad emission bands in the visible spectrum. Excited state lifetime measurements evidence the presence of non-radiative energy transfer processes between the Ag species to Nd3+ ions but there is no direct evidence of plasmon enhancement effects. In samples singly doped with silver, direct laser writing experiments using a femtosecond laser were also performed which induced localized growth of Ag-NCs associated to a variation in the refractive index. Preliminary results indicate the potential of the DLW technique for tailoring optical glass properties.
T2 - 27th International Congress on Glass 2025
CY - Kolkata, India
DA - 20.01.2025
KW - Gallium phosphofluoride glass
KW - Structure-property correlation
KW - Femtosecond direct laser writting
KW - Neodymium
PY - 2025
AN - OPUS4-63774
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heuser, Lina
T1 - Composition-structure-property relationships of ternary borate glasses
N2 - Since the pioneer work of Krogh-Moe [1] in the 1960’s the structure clarification of borate glasses is of interest for many generations. In the present contribution the composition–structure–property relationships of Me2O–ZnO–B2O3, Me = Li (LZB), Na (NZB), K (KZB), Rb (RZB), CaO–ZnO–B2O3 (CaZB), and Li2O–PbO–B2O3 (LPbB) glasses are investigated. Non-toxic, highly polarizable zinc oxide potentially substitutes harmful lead oxide in glasses for applications e.g., in photovoltaics and microelectronics. Glass structure was analyzed using Raman and infrared spectroscopy, and the glass properties were measured using dilatometry (Tg, viscosity data, coefficient of thermal expansion) and rotational viscometry (high-temperature viscosity) [2,3]. The spectroscopic results show that alkali and calcium ions largely balance out the negative charges of BO4-units, while zinc and lead ions mainly stabilize the non-bridging oxygen atoms (NBO). The type of network modifier ion directs formation of the BO4-containing groups and the number of BO4-units (N4). Thus, i.) BO4-containing pentaborate was assigned in LZB, NZB and CaZB glasses, and ii.) diborate in KZB and RZB glasses. Simultaneous presence of pentaborate and diborate was only detected in LPbB. The combination of modifier’s properties, i.e., lower Lewis’s basicity (Rb+ > Li+), higher field strength (Rb+ < Li+), lower polarizability (Rb+ > Li+), and steric effects with increasing size (Rb+ > Li+) [4], leads to slightly increasing N4 in the series RZB (0.36) ≈ KZB < NZB (0.37) < LZB ≈ CaZB (0.39). This increase in N4 results in an increase in the atomic packing density 0.519 (RZB) – 0.584 (LZB) and thus in the Young’s Modulus 38.1 GPa (RZB) – 92.5 GPa (LZB) and in the glass transition temperature (Tg) 444 °C (RZB) – 467 °C (LZB) in the alkali series. In reverse order the coefficient of thermal expansion decreases from 12·10-6 K-1 (RZB) – 8.54·10-6 K-1 (LZB) with increasing N4. Ca2+ in CaZB enhances the viscosity (Tg: 580 °C) compared to Li+ in isocompositional LZB due to higher coordination. On the other hand, Pb2+ in LPbB decreases the viscosity (Tg: 399 °C) compared to Zn2+ in LZB with similar molar fractions.
T2 - 98th Glass-Technology Conference of the German Society of Glass Technology (DGG)
CY - Goslar, Germany
DA - 26.05.2025
KW - Borate glasses
KW - Structure-property relationship
PY - 2025
AN - OPUS4-63771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xie, Zhuocheng
A1 - Atila, Achraf
A1 - Guénolé, Julien
A1 - Korte-Kerzel, Sandra
A1 - Al-Samman, Talal
A1 - Kerzel, Ulrich
T1 - Predicting grain boundary segregation in magnesium alloys: An atomistically informed machine learning approach
N2 - Grain boundary (GB) segregation substantially influences the mechanical properties and performance of magnesium (Mg). Atomic-scale modeling, typically using ab-initio or semi-empirical approaches, has mainly focused on GB segregation at highly symmetric GBs in Mg alloys, often failing to capture the diversity of local atomic environments and segregation energies, resulting in inaccurate structure-property predictions. This study employs atomistic simulations and machine learning models to systematically investigate the segregation behavior of common solute elements in polycrystalline Mg at both 0 K and finite temperatures. The machine learning models accurately predict segregation thermodynamics by incorporating energetic and structural descriptors. We found that segregation energy and vibrational free energy follow skew-normal distributions, with hydrostatic stress, an indicator of excess free volume, emerging as an important factor influencing segregation tendency. The local atomic environment’s flexibility, quantified by flexibility volume, is also crucial in predicting GB segregation. Comparing the grain boundary solute concentrations calculated via the Langmuir-McLean isotherm with experimental data, we identified a pronounced segregation tendency for Nd, highlighting its potential for GB engineering in Mg alloys. This work demonstrates the powerful synergy of atomistic simulations and machine learning, paving the way for designing advanced lightweight Mg alloys with tailored properties.
KW - Machine learning
KW - Grain boundary segregation
KW - Magnesium alloys
KW - Atomistic simulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638499
DO - https://doi.org/10.1016/j.jma.2025.03.021
SN - 2213-9567
VL - 13
IS - 6
SP - 2636
EP - 2650
PB - Elsevier B.V.
AN - OPUS4-63849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janczynski, Jessica
A1 - Tewes, Andreas
A1 - Ulbricht, Alexander
A1 - Jaenisch, Gerd-Rüdiger
T1 - Evaluation Metrics for Comparison between Virtual and Industrial XCT
N2 - Simulations of XCT systems, as employed in the context of the manufacturing and design process, represent a time-saving, cost- and resource-efficient alternative to repeated experimental measurements. This article is dedicated to the development and evaluation of various metrics that should enable an adequate verification and optimization of a XCT simulation of an experimental XCT system. The present study employed statistical evaluation as a methodological approach. The present article makes a significant contribution to the optimization of the development process of a XCT simulation and provides a foundation for future research activities in this field.
KW - Computed Tomography
KW - Computertomographie
KW - aRTist
KW - Simulation
KW - Virtual CT
KW - Evaluation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641444
DO - https://doi.org/10.1007/s10921-025-01213-w
SN - 0195-9298
VL - 44
IS - 4
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
CY - Berlin/Heidelberg
AN - OPUS4-64144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - The influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling
N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a ray-tracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized Level-Set method. The PLIC-based method is discrete, resulting in non-continuous free surface reconstruction. In the localized Level-Set method, a continuous free surface is reconstructed, and thus the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics.
T2 - International Congress of Applications of Lasers & Electro-Optics 2022
CY - Orlando, FL, USA
DA - 17.10.2022
KW - Laser beam welding
KW - laser energy distribution
KW - Weld pool dynamics
KW - Ray-tracing
PY - 2022
SP - 1
EP - 9
AN - OPUS4-56533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simón Muzás, Juan
T1 - Laser Welding of L PBF AM Components of Inconel 718
N2 - With regard to efficient production, it is desirable to combine the respective advantages of additively and conventionally manufactured components. Particularly in the case of large-volume components that also include filigree or complex structures, it makes sense to divide the overall part into individual elements, which afterwards have to be joined by welding.
The following research represents a first step in fundamentally investigating and characterizing the joint welding of Laser Powder Bed Fusion (L-PBF) components made of Inconel 718. For this purpose, bead-on-plate welds were performed on plates manufactured using the L-PBF process and compared with the conventionally manufactured material. Conventional laser beam welding was used as welding process. The weld geometry was investigated as a function of the L-PBF build-up orientation. It was found that the welding depth and weld geometry differ depending on this orientation and in comparison to the conventional material.
T2 - LANE-2022 Conference. 12th CIRP Conference on Photonic Technologies
CY - Fürth, Germany
DA - 04.09.2022
KW - Bead-on-plate welds
KW - Laser Welding
KW - L-PBF
KW - Inconel 718
KW - Weld geometry
PY - 2022
AN - OPUS4-55745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epple, Niklas
T1 - Monitoring of Concrete with Embedded Ultrasound Sensors, Coda Waves and a Novel Measurement Device
N2 - Using embedded ultrasound (US) sensors in civil engineering structures and Coda Wave Interferometry (CWI), DFG research group CoDA aims for developing methods of concrete damage assessment by combination of Micro and macro scale simulations and experiments. BAMs goal within the project is the provision of small and durable measurement equipment on the one hand, and the investigation of damage sensitive parameters and development of an imaging algorithm on the other hand. In this study we focus on the development of the measurement system and the influence of temperature variations on the measurements.
T2 - Summer School DFG FOR CoDA
CY - Berchtesgaden, Germany
DA - 27.09.2020
KW - Ultrasound
KW - Coda Wave Interferometry
KW - Structural Health Monitoring
PY - 2020
AN - OPUS4-51382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - John, Sebastian
A1 - Duffner, Eric
A1 - Mair, Georg W.
T1 - Degradation and damage analysis of composite pressure vessels via experimental modal analysis
N2 - For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests.
T2 - NOVEM Conference 2023
CY - Auckland, New Zealand
DA - 09.01.2023
KW - Composite material
KW - Pressure vessel
KW - Degradation
KW - Modal analysis
PY - 2023
SP - 57-1
EP - 57-6
AN - OPUS4-58062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - John, Sebastian
A1 - Duffner, Eric
T1 - Degradation and damage analysis of composite pressure vessels via experimental modal analysis
N2 - For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests.
T2 - NOVEM 2023
CY - Auckland, New Zealand
DA - 09.01.2023
KW - Pressure vessel
KW - Composite
KW - Modal analysis
KW - Degradation
PY - 2023
AN - OPUS4-58063
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deffo, Gullit
A1 - Tamo, Arnaud Kamdem
A1 - Fotsop, Cyrille Ghislain
A1 - Tchoumi, Honorine Hortense Bougna
A1 - Talla, Donald Eric Njiajo
A1 - Wabo, Calice Gildas
A1 - Deussi, Marcel Cédric Ngaha
A1 - Temgoua, Ranil Clément Tonleu
A1 - Doungmo, Giscard
A1 - Njanja, Evangeline
A1 - Tonle, Ignas Kenfack
A1 - Puzari, Panchanan
A1 - Birkemeyer, Claudia
A1 - Ngameni, Emmanuel
T1 - Metal-organic framework-based materials: From synthesis and characterization routes to electrochemical sensing applications
N2 - Metal-organic frameworks (MOFs) are formed by coordination bonds between organic ligands and metal ions or clusters. Their key properties, including high surface area, porosity, and adjustable functionalities, enable diverse applications in gas separation, catalysis, energy storage, luminescence, and more recently, the development of electrochemical sensors. In this review, we provide an overview of various electrochemical methods and discuss different MOF-based electrochemical sensors reported in the literature. We focus on the synthesis of MOFs, their characterization, and the preparation of MOF-based working electrodes for electroanalysis. A brief history of MOFs, along with their nomenclature, classifications, and features, is discussed to provide a chronological understanding of MOFs before delving into their electroanalytical uses. Recent advancements in the use of MOFs as electrode materials for electrochemical sensing have been extensively reviewed and documented, highlighting their increasing relevance in various analytical fields. This review investigates the key properties of MOFs that make them suitable candidates for sensing applications and the ability for post-synthesis modifications to improve their selectivity and sensitivity. It also examines the challenges associated with the synthesis and modification of MOFs, including issues related to scalability, eproducibility, and the stability of the materials under operational conditions. Furthermore, the review discusses potential future directions for the use of MOFs in electrochemical sensing, emphasizing their role as electrode materials to enhance the sensitivity and selectivity of modified sensors for sustainable applications.
KW - Metal-organic frameworks (MOFs)
KW - MOF synthesis and characterization
KW - Electrochemical sensors
KW - Electroanalysis
PY - 2025
DO - https://doi.org/10.1016/j.ccr.2025.216680
SN - 0010-8545
VL - 536
SP - 1
EP - 78
PB - Elsevier B.V.
AN - OPUS4-63742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - Workflow generation, management, and semantic description for Self-Driving Labs
N2 - The software backend that controls the robotic hardware and runs the synthesis workflows is a very important component of any Self-Driving Lab (SDL). On the one hand, it has to deal with orchestrating and managing complex and task-specific hardware through low-level communication protocols and plan and use the available resources as efficiently as possible while executing (parallelized) workflows, on the other hand, it is the interface the users use to communicate with this highly complex platform, and as such, it needs to be as helpful and user-friendly as possible. This includes the AI-aided experimental design in which the system helps the user to decide which experiment to run next, providing automated data analysis from characterization measurements, and offering easy to understand tools and graphical user interfaces for generating the workflows that are executed on the platform. Lastly, the specificity of the workflows and their dependence on the hardware and software of the SDLs necessitates a common description or ontology for making them easily interchangeable and interoperable between different platforms and labs.
In this contribution, we present several key aspects of “Minerva-OS”, the central backend that orchestrates the syntheses workflows of our SDL for Nano- and Advanced Materials Syntheses [1]. One key feature is the resource management or “traffic control” for scheduling and executing parallel reactions in a multi-threaded environment. Another is the interface with data analysis algorithms from in-line, at-line, and off-line measurements. Here, we will give examples of how automatic image segmentation of electron microscopy images with the help of AI [2] can be used for reducing the “data analysis bottleneck” from an off-line measurement. We will also discuss, compare, and show benchmarks of various machine learning (ML) algorithms that are currently implemented in the backend and can be used for ML-guided, closed-loop material optimization in our SDL. Lastly, we will show our recent efforts [3] in making the workflow generation on SDLs more user-friendly by using large language models to generate executable workflows automatically from synthesis procedures given in natural language and user-friendly graphical user interfaces based on node editors that also allow for knowledge graph extraction from the workflows. In this context, we are currently also working on an ontology for representing the process steps of the workflows, which will greatly facilitate the semantic description and interoperability of workflows between different SDL hardware and software platforms.
T2 - Accelerate 2025
CY - Toronto, Canada
DA - 11.08.2025
KW - Nanomaterials
KW - Advanced Materials
KW - Workflows
KW - Machine Learning
KW - SDL
PY - 2025
AN - OPUS4-63936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - Nano- and Advanced Materials Synthesis in a Self-Driving Lab (SDL)
N2 - Nano- and advanced materials have been recognized as a key enabling technology of the 21st century, due to their high potential of driving innovations in new clean energy technologies, sustainable manufacturing by substitution of critical raw materials and replacement of hazardous substances, breakthroughs in energy conversion and storage, improvement of the environmental performance of products and processes, and facilitation of circularity. Consequently, improving tools that enhance the development and optimization cycle of nano- and advanced materials is crucial.
In this contribution, we present our Self-Driving Lab (SDL) for Nano and Advanced Materials [1], that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nanomaterials – with automated characterization and data analysis, for a complete and reliable nanomaterial synthesis workflow. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. The system also exhibits high modularity and adaptability in terms of reaction scales and incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence) of the nanomaterials. We discuss the excellent reproducibility of the various materials synthesized on the platform in terms of particle size and size distribution, and the adaptability and modularity that allows access to a diverse set of nanomaterial classes. These features underscore the SDL’s potential as a transformative tool for advancing and accelerating the development of nano- and advanced materials, offering solutions for a sustainable and environmentally responsible future.
T2 - Accelerate 2025
CY - Toronto, Canada
DA - 11.08.2025
KW - Nanomaterials
KW - Advanced Materials
KW - Automation
KW - SDL
KW - MAP
PY - 2025
AN - OPUS4-63935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huber, Norbert
T1 - Testing and analysis of materials and components ‒ an expedition from lab to field in a digitally transforming world
N2 - In an era where digital transformation is reshaping every facet of our lives, the field of material science and engineering is no exception. This presentation delves into the exciting journey of material and component testing, tracing its path from the confines of the laboratory to the vast expanse of real-world applications, with a particular focus on enhancing safety and reliability. We will explore how modern techniques are pushing the boundaries of conventional material testing, revealing new dimensions of material behavior and performance that are crucial for ensuring safety. The integration of in situ quality control within production processes is revolutionizing manufacturing, ensuring unparalleled precision and reliability, which are essential for maintaining high safety standards.
As we venture into the realm of Structural Health Monitoring (SHM), discover how cutting-edge technologies are being deployed in field applications, from infrastructure to renewable energy sectors, to monitor and ensure the safety and integrity of critical systems. The presentation will also offer a glimpse into the future, where centralized systems for research data management and innovative digital initiatives promise to transform the landscape of material testing and analysis, further bolstering safety measures. Join us to uncover how these advancements are not only enhancing safety and reliability but also paving the way for a digitally interconnected world.
T2 - MaterialsWeek 2025
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - Characterization
KW - Materials testing
KW - In situ quality control
KW - Digitalization
PY - 2025
AN - OPUS4-63918
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huber, Norbert
T1 - Machine Learning Approaches for Intentional Materials Engineering
N2 - The development of nanoporous metals and metallic composites through dealloying processes presents significant opportunities in materials engineering. However, designing multicomponent precursor alloys and establishing corresponding processing methods that yield predictable compositions and nanostructures remain a complex challenge. The talk explores how machine learning (ML)-augmented computational and experimental methodologies can tackle these challenges by predicting precursor alloy compositions, final nanoporous structures, and mechanical properties, while integrating ML-enabled autonomous experimentation for material design and quantification. Recent advancements in applying ML to nanostructured materials design will be touched along with techniques from other nanomaterial designs that can be adapted for improved control over morphological and compositional outcomes in nanoporous and nanocomposite materials. The focus of the talk will be set on ML-driven approaches to microstructure characterization and mechanical property prediction, modeling, and advanced imaging techniques such as three-dimensional nanotomography. Finally, the talk outlines future directions for ML-enhanced materials science, emphasizing the exploration of high-dimensional parameter spaces and the incorporation of materials kinetics into processing and property evaluation, ultimately advancing the design of nanoporous structures and materials science.
T2 - MSE Research Data Forum 2025
CY - Siegburg, Germany
DA - 08.07.2025
KW - Nanoporous Metals
KW - Machine Learning
KW - Microstructure
KW - Mechanical Properties
KW - Structure-Properties-Relationship
PY - 2025
AN - OPUS4-63919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemiasheuski, Anton
A1 - Wehrkamp, F.
A1 - Bajer, Evgenia
A1 - Sonnenburg, Elke
A1 - Göbel, Artur
A1 - Porohovoj, Ilja
A1 - Bettge, Dirk
A1 - Pfennig, Anja
T1 - Practical application of an automated 3D metallography system for the reconstruction and microstructural analysis of porosity in a sintered steel
N2 - In the 3D microstructural analysis of a digital twin of porosity in the sintered steel Astaloy CrA, pore shape, average pore size as well as pore distribution will be analyzed. Porosity plays a major role in powder-metallurgical materials since it greatly impacts the mechanical properties of these materials and therefore represents a key parameter in their characterization. Based on the robot-assisted automated serial sectioning and imaging (RASI) system of the Federal Institute for Materials Research and Testing (BAM, Bundesanstalt für Materialforschung und Prüfung) in Berlin, the technique of metallographic serial sectioning will be used to image the microstructure and reconstruct a digital 3D twin from the stack of images obtained. Compared with an individual 2D microsection, the quantitative microstructural analysis of this 3D twin will enable more accurate conclusions on the shape, size and distribution of pores. This paper will detail the key steps in 3D microstructural analysis, including the metallographic preparation routine, the imaging technique, image alignment as well as the segmentation of pores. After the methodology has been described, the results of the quantitative microstructural analysis will be presented and the validity of quantitative parameters of 3D and 2D images will be compared and discussed. The analysis of more than 10,000 pores revealed a correlation between pore shape and pore size. It was also found that a 2D representation of the material surface is insufficient for a precise quantitative characterization of porosity.
N2 - In der 3D-Gefügeanalyse eines digitalen Zwillings von Poren in einem Sinterstahl des Typs Astaloy CrA werden sowohl die Porenform als auch die durchschnittliche Porengröße und -verteilung analysiert. Die Porosität spielt in pulvermetallurgischen Werkstoffen eine große Rolle, da sie erheblich die mechanischen Eigenschaften beeinflusst und daher bei der Charakterisierung dieser Werkstoffe ein wichtiger Parameter ist. Basierend auf der Verwendung des Robot-Assisted Automated Serial-Sectioning and Imaging (RASI)-Systems der Bundesanstalt für Materialforschung und Prüfung (BAM) in Berlin, wird das metallographische Serienschnittverfahren genutzt, um das Gefüge aufzunehmen und aus dem Bildstapel einen digitalen 3D-Zwilling zu rekonstruieren. Verglichen zu einem 2D-Einzelschliff ermöglicht die quantitative Gefügeanalyse dieses 3D-Zwillings präzisere Aussagen zu Porenform, -größe und -verteilung. Diese Arbeit beschreibt die wesentlichen Schritte, die für eine 3D-Gefügeanalyse nötig sind, darunter die metallografische Präparationsroutine, das Bildgebungs-Verfahren, das Alignment der Bilder sowie die Segmentierung der Poren. Im Anschluss an die methodische Darstellung werden die Ergebnisse der quantitativen Gefügeanalyse präsentiert und ein Vergleich zwischen der Aussagekraft der quantitativen Parameter von 3D- und 2D-Abbildungen diskutiert. Bei der Analyse von über 10.000 Poren konnte eine Korrelation zwischen der Form und der Porengröße aufgezeigt werden. Weiterhin konnte aufgezeigt werden, dass eine 2D-Abbildung der Werkstoffoberfläche nicht ausreichend für eine eindeutige quantitative Beschreibung der Porosität ist.
KW - 3D Metallographie
KW - RASI
KW - Porenstruktur
PY - 2025
DO - https://doi.org/10.1515/pm-2025-0049
SN - 2195-8599
VL - 62
IS - 8
SP - 516
EP - 535
PB - De Gruyter Brill
AN - OPUS4-63930
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - Nano- and Advanced Materials Synthesis in a Self-Driving Lab (SDL)
N2 - Nano- and advanced materials have been recognized as a key enabling technology of the 21st century, due to their high potential of driving innovations in new clean energy technologies, sustainable manufacturing by substitution of critical raw materials and replacement of hazardous substances, breakthroughs in energy conversion and storage, improvement of the environmental performance of products and processes, and facilitation of circularity. Consequently, improving tools that enhance the development and optimization cycle of nano- and advanced materials is crucial.
In this contribution, we present our Self-Driving Lab (SDL) for Nano and Advanced Materials [1], that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nanomaterials – with automated characterization and data analysis, for a complete and reliable nanomaterial synthesis workflow. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. The system also exhibits high modularity and adaptability in terms of reaction scales and incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence) of the nanomaterials. We discuss the excellent reproducibility of the various materials synthesized on the platform in terms of particle size and size distribution, and the adaptability and modularity that allows access to a diverse set of nanomaterial classes. These features underscore the SDL’s potential as a transformative tool for advancing and accelerating the development of nano- and advanced materials, offering solutions for a sustainable and environmentally responsible future.
T2 - Accelerate 2025
CY - Toronto, Canada
DA - 11.08.2025
KW - Nanomaterials
KW - Advanced Materials
KW - Automation
KW - SDL
KW - MAP
PY - 2025
AN - OPUS4-63934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mege-Revil, Alexandre
A1 - Rapontchombo-Omanda, Jessie
A1 - Serrano-Munoz, Itziar
A1 - Cristol, Anne-Lise
A1 - Magnier, Vincent
A1 - Dufrenoy, Philippe
T1 - Sintered Brake Pads Failure in High-Energy Dissipation Braking Tests: A Post-Mortem Mechanical and Microstructural Analysis
N2 - The industrial sintering process used to produce metallic matrix pads has been altered to diminish the amount of copper used. Unfortunately, replacing a large part of the copper with iron seems to have reached a limit. In the high-energy, emergency-type rail braking used in this study, the materials are put to the very limit of their usage capacity, allowing us to observe the evolution of the microstructure and mechanical properties of sintered, metallic matrix pads. After the braking test, their compressive behaviour was assessed using digital image correlation (DIC), and their microstructure with scanning electron microscopy (SEM). The worn material has three flat layers with different microstructures and compressive behaviours. The boom layer seems unmodified. Macroscopic and microscopic cracks run through the intermediate layer (2–15 mm depth). The top layer has stiffened thanks to resolidification of copper. The temperature reaches 1000 °C during the braking test, which also explains the carbon diffusion into iron that result in the weakening of iron–graphite interfaces in the pad. Finally, submicronic particles are detected at many open interfaces of the worn and compressed pad. Associated with the predominant role of graphite particles, this explains the weak compressive behaviour of the pads.
KW - Friction braking
KW - Sintering
KW - Metallic matrix pad
KW - Microstructure
KW - Scanning electron microscopy (SEM)
KW - Compressive test
KW - Cracks
KW - Digital image correlation (DIC)
KW - Diffusion
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587318
DO - https://doi.org/10.3390/ma16217006
SN - 1996-1944
VL - 16
IS - 21
SP - 1
EP - 18
PB - MDPI
AN - OPUS4-58731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Magnier, V.
A1 - Brunel, F.
A1 - Dufrenoy, P.
T1 - Influence of the Composition on the Compressive Behaviour of a Semi-Metallic Brake-Pad Material
N2 - The contact interface between the rotation and static part of a friction brake is central to the optimal functioning of the brake system due to the occurrence of heat dissipation, mechanical interaction and thermal exchanges. Generally, braking performances are evaluated by the energetic efficiency and wear rates of the contact surface. However, the compressive behaviour of the contact materials has also a significant contribution to the overall performances. In this work, the meso- and microscopic compressive behaviour of a sintered semi-metallic brake-pad material is investigated mainly via compression testing coupled with Digital Image Correlation (DIC) technique, as well as optical and scanning electron microscopy (SEM) analysis. The composition of a reference material (RM) is simplified to a selection of nine components, as opposed to up to thirty components typically used in commercial brake-pad materials. The retained components are considered as the most crucial for safe-operating performances. At the studied stress levels, the RM material is flexible (E = 5330 MPa), deformable (Ezz−plastic = −0.21%), and exhibits hysteresis loops. Subsequently, the contribution to the mechanical response of each individual component is investigated by producing the so-called dissociated materials, where the number of components is, at a time, further reduced. It is observed that the macroscopic behaviour is mainly controlled by the content (i.e., size distribution, shape and nature) of graphite particles, and that the hysteresis is only related to one of the two types of graphite used (G2 particles). Moreover, RM containing 13 wt% of G2 particles embedded in a relatively soft matrix (10.86 GPa) is able to increase the hysteresis (by 35%) when compared to the dissociated material containing 20 wt% of G2 particles which is embedded in a stiffer matrix (E = 106 GPa).
KW - Semi-metallic brake-pad material
KW - Powder metallurgy
KW - Components influence
KW - Graphite induced hysteresis
KW - Digital image correlation (DIC)
KW - Compression testing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562003
DO - https://doi.org/10.3390/ma15227911
VL - 15
IS - 22
SP - 7911
PB - MDPI
AN - OPUS4-56200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Walter, Keven
A1 - Hoch, Dominik P.
A1 - Hertweck, Leon
A1 - Balasubramanian, Kannan
A1 - Geisler, Jonas
A1 - Röllig, Mathias
A1 - Neubert, Tilmann J.
A1 - Börner, Hans G.
T1 - Unlocking the Essence of Lignin: High‐Performance Adhesives That Bond via Thiol‐Catechol Connectivities and Debond on Electrochemical Command
N2 - AbstractThe next generation of adhesives requires effective debonding capabilities that can be triggered on demand to enable advanced circular repair and recycling strategies. A new class of lignin‐inspired, two‐component (2K) structural adhesives offers bonding strengths of up to 20 MPa and clean, on‐command electrochemical debonding within 5–30 min. The debonding is induced by a distinct electrochemical oxidation of thiol‐catechol connectivities (TCCs) within the entire adhesive network, enforcing rapid and clean adhesive failure on the cathodic substrate side. The TCC‐functionalities are formed during curing by a thiol‐quinone Michael‐type polyaddition, reacting polyester‐based trithiols with tris‐quinones as lignin‐inspired minimal building blocks. The structural adhesive can be fine‐tuned by adjusting the formulation. The addition of carbon black and ionic liquids facilitates the desired electrochemical transformation of TCC‐catechols to TCC‐quinones. Applying only 9 V for 5–30 min, leads to clean debonding with 72–86% loss of shear strength. A comprehensive study of curing, bonding, and debonding behavior by rheological, spectroscopic, and electrochemical investigations reveals the debonding mechanism by correlating catechol oxidation to adhesive performance. The electrochemical debonding capability of TCC‐structural adhesives is demonstrated in a functional prototype, where on‐command detachment of a cover glass from a display device is achieved within 6.5 min.
KW - Lignin-inspired
KW - Electrochemical-Debonding
KW - Thiol-Catechol-Connectivity (TCC)
KW - Michael-Type Polyaddition
KW - On-Demand Adhesive Failure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639674
DO - https://doi.org/10.1002/adma.202510463
SN - 0935-9648
SP - 1
EP - 10
PB - Wiley VHC-Verlag
CY - 69451 Weinheim
AN - OPUS4-63967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-Driven Chemical Understanding
N2 - This talk presents my research on data-driven chemical understanding to graduate students in chemistry at the Graduate School Chemistry in Paris.
T2 - Workshop : Practical applications of Machine Learning in chemistry: perspectives and pitfalls
CY - Paris, France
DA - 13.07.2022
KW - Chemical Understanding
KW - Automation
KW - Bonding Analysis
PY - 2022
UR - https://gs-chem13.sciencesconf.org/
AN - OPUS4-55410
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automated bonding analysis based on crystal orbital Hamilton populations
N2 - We created a workflow that fully automates bonding analysis using Crystal Orbital Hamilton Populations, which are bond-weighted densities of states. This enables understanding of crystalline material properties based on chemical bonding information. To facilitate data analysis and machine-learning research, our tools include automatic plots, automated text output, and output in machine-readable format.
T2 - Sommersymposium des Fördervereins Chemieolympiade
CY - Online meeting
DA - 25.06.2022
KW - Bonding Analysis
KW - Automation
KW - DFT
PY - 2022
AN - OPUS4-55409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding with geometrical and quantum-chemical bonding analysis
N2 - Chemical bonding and coordination environments are crucial descriptors of material properties. They have previously been applied to creating chemical design guidelines and chemical heuristics. They are currently being used as features in machine learning more and more frequently. I will discuss implementations and algorithms (ChemEnv and LobsterEnv) for identifying these coordination environments based on geometrical characteristics and chemical bond quantum chemical analysis. I'll demonstrate how these techniques helped in testing chemical heuristics like the Pauling rule and thereby improved our understanding of chemistry. I'll also show how these tools can be used to create new design guidelines and a new understanding of chemistry. To use quantum-chemical bonding analysis on a large-scale and for machine-learning approaches, fully automatic workflows and analysis tools have been developed. After presenting the capabilities of these tools, I will also point out how these developments relate to the general trend towards automation in the field of density functional based materials science.
T2 - ICAMS Interdisciplinary Centre for Advanced Materials Simulation Seminar Series
CY - Online meeting
DA - 24.11.2022
KW - Automation
KW - High-throughput
KW - Machine learning
KW - Materials informatics
KW - Bonding Analysis
PY - 2022
AN - OPUS4-56417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding with geometrical and quantum-chemical bonding analysis
N2 - Chemical bonding and coordination environments are crucial descriptors of material properties. They have previously been applied to creating chemical design guidelines and chemical heuristics. They are currently being used as features in machine learning more and more frequently. I will discuss implementations and algorithms (ChemEnv and LobsterEnv) for identifying these coordination environments based on geometrical characteristics and chemical bond quantum chemical analysis. I will demonstrate how these techniques helped in testing chemical heuristics like the Pauling rule and thereby improved our understanding of chemistry. I will also show how these tools can be used to create new design guidelines and a new understanding of chemistry. To use quantum-chemical bonding analysis on a large-scale and for machine-learning approaches, fully automatic workflows and analysis tools have been developed. After presenting the capabilities of these tools, I will also point out how these developments relate to the general trend towards automation in the field of density functional based materials science.
T2 - UniSysCat - Colloquium
CY - Berlin, Germany
DA - 08.02.2023
KW - Automation
KW - Chemical Bonds
KW - High-throughput
KW - Data Analysis
PY - 2023
UR - https://www.unisyscat.de/news-events/display?tx_news_pi1%5Baction%5D=detail&tx_news_pi1%5Bcontroller%5D=News&tx_news_pi1%5Bnews%5D=386&cHash=f95c8af783c08c2c6039440145a036bb
AN - OPUS4-57051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automation and Workflows in Computational Materials Science
N2 - This talks describes why we need automation and workflows in materials informatics. It introduces tools to automatize tasks in computational materials science. Furthermore, a bonding analysis and a phonon workflow are presented.
T2 - Seminar in Theoretical Chemistry Group atFU Berlin
CY - Berlin, Germany
DA - 06.12.2022
KW - Automation
KW - Workflows
KW - Density functional theory
PY - 2022
AN - OPUS4-56524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automation and workflows incomputational materials science
N2 - This talk introduced the audience to automation and workflows in the field of computational materials science. The audience were the members of the FONDA Sonderforschungsbereich at HU Berlin
T2 - FONDA Seminar Series
CY - Berlin, Germany
DA - 10.10.2022
KW - Automation
KW - Workflows
KW - Materials Informatics
PY - 2022
AN - OPUS4-56419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Mit Hilfe künstlicher Intelligenz neue Materialien finden
N2 - In diesem Vortrag für Schüler*innen, die an der nationalen Auswahl der internationalen Chemieolympiade teilnehmen, stellte ich meinen akademischen Werdegang und das Fach Materialinformatik und die Forschung in diesem Bereich vor.
T2 - Landesseminar zur Internationalen Chemieolympiade in Berlin-Brandenburg
CY - Berlin, Germany
DA - 30.10.2022
KW - Materialinformatik
KW - Automatisierung
KW - Computerchemie
PY - 2022
AN - OPUS4-56128
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Vibe Check via Machine Learning: Testing the Prototype
N2 - Vibrational properties play a key role in determining the stability and thermal conductivity behaviour of materials. The quasi- harmonic approximation gives insight into the phononic properties of a compound, but in the established way, i.e. density functional theory based methods, it takes many calculation steps and consumes a lot of resources to arrive at the desired results. Machine learning (ML) trained interatomic potentials (e.g. Gaussian approximation potential, GAP) pose an alternative to the traditional computation way of phonons. We develop a Python code based workflow which combines automation tools like atomate2 with ML to ease providing interactomic potentials for (quantum chemical) computations and databases.
T2 - #RSCPoster Twitter conference 2023
CY - Online meeting
DA - 28.02.2023
KW - Interatomic potentials
KW - Machine learning
KW - Phonons
KW - Workflow
PY - 2023
UR - https://twitter.com/cer5814012/status/1630547004462858240
AN - OPUS4-57059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash
T1 - New descriptors for materials properties based on bonding indicators
N2 - Includes a summary of the Ph.D. project that deals with generating a database populated with materials bonding properties and how we intend to gain deeper insights into material properties through this research.
T2 - SALSA 2022
CY - Berlin, Germany
DA - 15.09.2022
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
PY - 2022
AN - OPUS4-56142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding with geometrical and quantum-chemical bonding analysis
N2 - Talk about my recent research on data-driven chemical understanding with geometrical and quantum-chemical bonding analysis.
T2 - Donnerstagskolloquium IPC/IAAC
CY - Münster, Germany
DA - 04.05.2023
KW - Automation
KW - Machine learning
KW - Bonding Analysis
PY - 2023
AN - OPUS4-57431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash
T1 - Building quantum chemical orbital based bonding descriptor database
N2 - Motivation, methodology and and results of our quantum chemical bonding descriptors database presented in form of a Poster
T2 - RSC Twitter Conference 2023
CY - Online meeting
DA - 28.02.2023
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
UR - https://twitter.com/NaikAak/status/1630400167080869893
UR - https://twitter.com/NaikAak/status/1630540436434558977
AN - OPUS4-57101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding and machine learning of materials properties
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics for materials. More and more frequently, they are used as features in machine learning. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying these local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale and for machine-learning approaches. The latter relates to a general trend toward automation in density functional-based materials science. The lecture will demonstrate how our tools, that assess local atomic environments, helped to test and develop heuristics and design rules and an intuitive understanding of materials.
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Irland
DA - 03.07.2023
KW - Automation
KW - Bonding Analysis
KW - Materials Informatics
PY - 2023
AN - OPUS4-57876
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
T1 - Fraktographie mit Hilfe von klassischen Methoden und Machine Learning – bisherige Erfahrungen und Anwendung auf weitere Fragestellungen
N2 - In der Schadensanalyse und bei der Bewertung von mechanischen Experimenten liefert die Fraktographie Informationen über die vorliegenden Bruchmerkmale und den Bruchmechanismus eines Bauteils oder einer Probe. Im Rahmen des DGM AK Fraktographie werden an metallischen Werkstoffen Vergleichsexperimente durchgeführt und die Ergebnisse in einer Datenbank zur Verfügung gestellt. In einem Vorhaben wurde die Analyse von Bruchmerkmalen mittels Topographie-Daten und Machine Learning erprobt. Die gewonnenen Erfahrungen könnten auf weitere Anwendungsfälle wie z.B. Schweißverbindungen angewendet werden.
T2 - Erfahrungsaustausch Werkstoff- und Bauteilprüfung
CY - Halle, Germany
DA - 04.09.2025
KW - Fraktographie
KW - Machine Learning
KW - Schadensanalyse
KW - Schweißverbindungen
PY - 2025
AN - OPUS4-64032
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Colombo, Marta
A1 - Mostoni, Silvia
A1 - Fredi, Giulia
A1 - Rodricks, Carol
A1 - Kalinka, Gerhard
A1 - Riva, Massimiliano
A1 - Vassallo, Andrea
A1 - Di Credico, Barbara
A1 - Scotti, Roberto
A1 - Zappalorto, Michele
A1 - D'Arienzo, Massimiliano
T1 - Interfacial Chemistry Behind Damage Monitoring in Glass Fiber‐Reinforced Composites: Attempts and Perspectives
N2 - Glass Fiber Reinforced Polymers (GFRPs) are widely used in structural applications but degrade over time due to internal damage. Structural Health Monitoring (SHM) enables early damage detection, improving reliability and reducing maintenance costs. Traditional SHM methods are often invasive and expensive. An emerging solution involves the embedding of carbon‐based filler like carbon nanotubes and reduced graphene oxide into GFRPs, forming conductive networks that detect damage through resistance changes. However, poor adhesion among GF, filler, and matrix can reduce mechanical performance. Therefore, tailoring GF and filler surface chemistry is essential to enhance durability and enable effective self‐sensing properties. This review summarizes the most recent efforts in modifying GF with carbon‐based filler to design GFRP with improved sensing ability and mechanical performance. After a brief introduction on the role of SHM solutions in early damage detection, an overview of the common GF and filler used in GFRPs will be provided. Then, the most relevant GF modification strategies exploited to incorporate carbon‐based filler in GFRPs will be described, focusing on the chemical grafting approach, which allows a careful optimization of the fiber/matrix interface. Last, a concise summary of the key mechanical and electrical tests to evaluate interfacial adhesion and self‐sensing will be supplied.
KW - Review
KW - Interface
KW - Micromechanics
KW - Polymer matrix composites
KW - Glass fibre reinforced composites
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639934
DO - https://doi.org/10.1002/pc.70332
SN - 0272-8397
SP - 1
EP - 30
PB - Wiley
AN - OPUS4-63993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hülagü, Deniz
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - de Préville, Sophie
A1 - Hoffmann, Johannes
A1 - Morán‐Meza, José
A1 - Piquemal, François
A1 - Hertwig, Andreas
T1 - Multimethod Electrical Characterization of Thin Indium Tin Oxide Films: Structuring and Calibration Sample Development for Scanning Probe Microscopy
N2 - Indium tin oxide (ITO), a transparent conductive oxide, is widely used in optoelectronic applications due to its electrical conductivity, optical transparency, and chemical stability. This study employs spectroscopic ellipsometry (SE) to analyze ITO layers, enabling nondestructive determination of film thickness, dielectric functions, and bulk conductivity. Electrical properties derived from SE are compared with those obtained using the four‐point probe method (4PM) to improve metrological tools for nanotechnology applications and optimize deposition process monitoring for better control of film properties. This work also investigates the chemical stability of ITO layers under etching conditions and explores the development of new sheet resistance standards for scanning microwave microscopy (SMM). The results show that ITO resistivity, calculated from fitted SE data, increases with oxygen flow rate up to 5 cm3(STP) min−1. Good agreement is observed between sheet resistance values obtained by SE and 4PM up to 3 cm3(STP) min−1. Additionally, the sheet resistance values of a distinct set of microstructured ITO samples with different ITO layer thicknesses are determined by SMM, which are highly consistent with those obtained by the 4PM.
KW - Ellipsometry
KW - Indium tin oxide (ITO)
KW - Scanning microwave microscopy (SMM)
KW - Sheet resistance calibration standards
KW - ITO wet etching
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626242
DO - https://doi.org/10.1002/pssa.202400871
SN - 1862-6300
VL - 222
IS - 14
SP - 1
EP - 18
PB - Wiley
CY - Hoboken, New Jersey, USA
AN - OPUS4-62624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munzke, Dorit
A1 - Duffner, Eric
A1 - Eisermann, René
A1 - Schukar, Marcus
A1 - Schoppa, André
A1 - Szczepaniak, Mariusz
A1 - Strohhäcker, J.
A1 - Mair, Georg W.
T1 - Monitoring of type IV composite pressure vessels with multilayer fully integrated optical fiber based distributed strain sensing
N2 - We present the results of distributed fiber optic strain sensing for condition monitoring of a hybrid type IV composite fully wrapped pressure vessel using multilayer integrated optical fibers. Distributed strain sensing was performed for a total number of 252,000 load cycles until burst of the vessel. During this ageing test material fatigue could be monitored and spatially localized. Critical material changes were detected 17,000 cycles before material failure. Results have been validated by acoustic emission analysis.
T2 - 12th International Conference on Composite Science and Technology (ICCST12)
CY - Sorrento, Italy
DA - 08.05.2019
KW - Hybrid composite pressure vessel
KW - Distributed fiber optic sensing
KW - Acoustic emission analysis
KW - Structural health monitoring
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516772
DO - https://doi.org/10.1016/j.matpr.2020.02.872
SN - 2214-7853
VL - 34
SP - 217
EP - 223
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-51677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmusto, Juho
T1 - Initial oxidation of the refractory high-entropy superalloy AlMo0.5NbTa0.5TiZr
N2 - In contrast to traditional alloys, which are typically based on a single dominant element, high-entropy alloys (HEAs) consist of five or more principal elements in roughly equal proportions. These complex alloys often exhibit superior characteristics compared to conventional alloys, including enhanced strength and hardness, exceptional wear resistance, high structural stability, and strong resistance to oxidation. Despite these promising characteristics, the vast compositional space of HEAs means that only a limited number have been thoroughly investigated for their mechanical and chemical behavior. One notable example is the refractory high-entropy superalloy AlMo0.5NbTa0.5TiZr, which represents a newly emerging class of materials. This alloy features a nanoscale microstructure composed of B2 and bcc phases, resulting in compressive strength at elevated temperatures that surpasses that of conventional Ni-based superalloys. Such performance offers potential benefits for improving turbine efficiency in aerospace and energy generation applications. However, the alloy’s microstructure is known to be sensitive to annealing. Specifically, its mechanical properties deteriorate when intragranular hexagonal Al-Zr-based intermetallic compounds form, likely due to issues with phase stability. On the other hand, the inclusion of Al has been shown to enhance oxidation resistance. Nevertheless, HEAs are also known to develop pronounced internal aging zones caused by diffusion during oxidation processes. These findings indicate a need for further investigation into the thermodynamic stability of this alloy. In addition, its oxidation behavior—both at the surface and within the material—remains incompletely understood. This ongoing research explores the oxidation behavior of the AlMo0.5NbTa0.5TiZr alloy at temperatures ranging from 800 °C to 1000 °C. The influence of water vapor on the oxidation process is also examined. Ultimately, the goal is to integrate insights into the alloy’s structural, mechanical, and chemical characteristics at high temperatures.
T2 - Gordon Research Conference - High Temperature Corrosion
CY - New London, United States
DA - 16.07.2023
KW - High-Entropy superalloy
KW - Phase stability
KW - Microstructural evolution
KW - Oxidation behavior
KW - High-Temperature Performance
PY - 2023
AN - OPUS4-63851
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Robens-Radermacher, Annika
T1 - Efficient cooling time optimization in Wire Arc Additive Manufacturing using a multi-layer reduced order model
N2 - Additive manufacturing (AM) has transformed the industry by enabling the production of complex geometries and parts with customized properties. Among various AM techniques, wire arc additive manufacturing (WAAM) stands out due to its high deposition rate and low equipment cost. However, WAAM’s complex thermal history poses challenges for real-time simulation, essential for online process control and optimization. Consequently, experimental optimization remains the state-of-the-art approach. A critical parameter to optimize is the cooling phase duration, which prevents structural overheating, controls the molten pool size, and influences the mechanical properties of the final product.
For efficient cooling time optimization, a fast-to-evaluate model of the temperature field during multi-layer deposition is necessary. This study proposes a reduced order model (ROM) using the proper generalized decomposition (PGD) method as a powerful tool to minimize computational effort. Given the moving heat source in WAAM processes, a mapping approach is employed to achieve a fully separated representation of the temperature field. Building on the authors’ previous one-layer approach, this contribution extends the model to multiple layers through enhanced mapping and compression techniques. The compression reduces the total number of PGD modes as the number of layers increases. The extended mapping allows computations with a fixed mesh over the simulation time, in contrast to standard methods such as the element birth technique.
For cooling time optimization, the cooling duration of each layer is incorporated as PGD variables, enabling time-efficient computation of the temperature field for varying cooling times. The developed ROM is applied to optimize the cooling time of a multiple layer example. Therefore a 5-10 layer wall structure is investigated using the austenitic stainless steel 1.4404 (AISI 316 L). The resulting cooling times and the efficiency of the approach are discussed.
T2 - 12th European solid mechanics conference (ESMC)
CY - Lyon, France
DA - 07.07.2025
KW - Model order reduction
KW - Proper generalized decomposition
KW - Welding
KW - Additive manufacturing
KW - Optimzation
PY - 2025
UR - https://esmc2025.sciencesconf.org/
AN - OPUS4-63855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Niebergall, Ute
A1 - Marschall, Niklas
A1 - Meinel, Dietmar
A1 - Böhning, Martin
T1 - Relation of craze to crack length during slow crack growth phenomena in high‐density polyethylene
N2 - The craze‐crack mechanism occurring in high‐density polyethylene (HDPE) causing slow crack growth and environmental stress cracking is investigated in detail with respect to the relation of crack length and the related craze zone. This is essential for the understanding of the resulting features of the formed fracture surface and their interpretation in the context of the transition from crack propagation to ductile shear deformation. It turns out that an already formed craze zone does not inevitably result in formation of a propagating crack, but could also undergo ductile failure. For the examination, the full notch creep test (FNCT) was employed with a subsequent advanced fracture surface analysis that was performed using various imaging techniques: light microscopy, laser scanning microscopy, scanning electron microscopy, and X‐ray micro computed tomography scan. FNCT specimens were progressively damaged for increasing durations under standard test conditions applying Arkopal, the standard surfactant solution, and biodiesel as test media were used to analyze the stepwise growth of cracks and crazes. From considerations based on well‐established fracture mechanics approaches, a theoretical correlation between the length of the actual crack and the length of the preceding craze zone was established that could be evidenced and affirmed by FNCT fracture surface analysis. Moreover, the yield strength of a HDPE material exposed to a certain medium as detected by a classic tensile test was found to be the crucial value of true stress to induce the transition from crack propagation due to the craze‐crack mechanism to shear deformation during FNCT measurements.
Highlights
- Progress of crack formation in high‐density polyethylene is analyzed by different imaging techniques
- Determined growth rates depend on distinction between craze zone and crack
- The ratio of the present crack to the anteceding craze zone is validated theoretically
- The transition from crack propagation to ductile shear deformation is identified
- An already formed craze zone may still fail by ductile mechanisms
KW - Craze-crack mechanism
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Laser scanning microscopy (LSM)
KW - Slow crack growth (SCG)
KW - X-ray computed tomography (CT)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601831
DO - https://doi.org/10.1002/pen.26698
SN - 1548-2634
VL - 64
IS - 6
SP - 2387
EP - 2403
PB - Wiley
AN - OPUS4-60183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thuy, Maximilian
A1 - Niebergall, Ute
A1 - Oehler, H.
A1 - Alig, I.
A1 - Böhning, Martin
T1 - Damaging effect of admixtures used in crop protection products on high density polyethylene packaging material
N2 - The phenomenon of environmental stress cracking is still a major issue in materials engineering as well as from a scientific perspective. Especially in the case of packaging materials made of high-density polyethylene, assessing the potential of premature damage due to environmental stress cracking is complex because of the large number of components in possible liquid filling goods. As a first guideline, the well-known effect of detergents and dispersants is usually considered, but the interplay with other components, such as organic solvents is often unknown. Particularly challenging in this respect are crop protection products, consisting of several different admixtures in addition to the biologically active ingredients. This study is based on two model liquids representing these admixtures that were established for testing in this context. The model liquids as well as their constituting components were used as liquid media in the Full Notch Creep Test to characterize the environmental stress cracking behavior of a typical high-density polyethylene. Complementary to the time-to failure of a notched specimen obtained from these tests, the crack opening was monitored optically, and the fracture surface was analyzed post-failure by laser scanning microscopy as well as scanning electron microscopy. Based on the results, the effect of various surfactants as well as the influence of organic solvents on environmental stress cracking are discussed.
KW - Environmental stress cracking
KW - High-density polyethylene
KW - Crop protection products
KW - Full notch creep test
KW - Fracture surface analysis
KW - Crack opening displacement
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554631
DO - https://doi.org/10.1016/j.polymertesting.2022.107672
SN - 0142-9418
VL - 114
SP - 1
EP - 16
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-55463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
A1 - Serrano-Munoz, Itziar
T1 - Multiscale residual stress analysis and synchrotron X-ray refraction of additively manufactured parts
N2 - The overview of the activity of group 8.5 Micro-NDT (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The challenges in the residual stress analysis of AM components are discussed on the basis on the show studies performed in BAM. Also, the synchrotron X-ray refraction technique, available in BAM, is presented, showing example of in-situ heating test of Al10SiMg AM material.
T2 - Seminar at Grenoble INP, Science et Ingénierie des Matériaux et Procédés (SIMaP)
CY - Grenoble, France
DA - 01.07.2022
KW - Additive manufacturing
KW - Residual stress
KW - X-ray refraction
KW - Computed tomography
PY - 2022
AN - OPUS4-55232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - 3D imaging and residual stress analysis for AM Materials
N2 - Metal Additive Manufacturing (AM) technologies such as Laser Powder Bed Fusion (LPBF) are characterized by layer wise construction, which enable advancements of component design, leading to potential efficiency and performance improvements. However, the rapid cooling rates associated with the process consequently leads to the generation of high magnitude residual stresses (RS). Therefore, a deep understanding of the formation of RS, the influence of process parameters on their magnitude and the impact on mechanical performance is crucial for widespread application. The experimental characterization of these RS is essential for safety related engineering application and supporting the development of reliable numerical models. Diffraction-based methods for RS analysis using high energy synchrotron X-rays and neutrons enable non-destructive spatially resolved characterization of both surface and bulk residual stresses in complex components. This presentation will provide an overview of recent research conducted by the BAM at large scale facilities for the characterization of residual stresses in LPBF metallic alloys. Special focus will be given to the challenges posed by textured LPBF materials for the reliable choice of the diffraction elastic constants (DECs), which is crucial to the accurate calculation of the level of RS.
T2 - Seminar at LTDS, Ecole Centrale de Lyon
CY - Lyon, France
DA - 15.06.2023
KW - Residual stress
KW - Additive manufacturing
KW - Diffraction methods
PY - 2023
AN - OPUS4-57808
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Magnier, Vincent
A1 - Dufrenoy, Philippe
T1 - Identification of damage mechanisms in a metal-matrix composite material via digital volume correlation and finite element model updating
N2 - A 3D experimental and numerical investigation of the damage mechanisms induced by compression in a metal matrix composite is presented. The investigated composite is a simplified version of those typically used for heavy-duty brake linings, comprising only nine constituents. The analysis combines laboratory X-ray computed tomography (XCT), image volume correlation (DVC), as well as image-based finite element method (FEM) paired with an inverse identification approach known as finite element model updating (FEMU). The combination of in situ XCT and DVC allows the rationalization of the mechanisms controlling strain localization and damage accumulation within the heterogeneous metal matrix. The damage mainly occurs in the form of fractured material within thin cell-walls located between large graphite G2 particles. In addition, the herein developed FEMU approach enables the identification of the elastic moduli of the two defined key constituents controlling the macroscopic compressive behavior (i.e., the Matrix –where eight of the nine constituents are lumped– and G2 particles), as well as the prediction of the damaged regions within the Matrix. It is emphasized that an implementation of the damage mechanisms within the FEMU is essential for a reliable numerical prediction of the compressive response of the composite.
KW - Metallic brake lining
KW - Compression tests
KW - In situ X-ray computed tomography (XCT)
KW - Image-based finite element method (FEM)
KW - Damage mechanisms
KW - Digital volume correlation (DVC)
KW - Finite element model updating (FEMU)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639388
DO - https://doi.org/10.1016/j.mtcomm.2025.113459
SN - 2352-4928
VL - 48
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-63938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santi, Alberto
A1 - Schröder, Jakob
A1 - Serrano-Munoz, Itziar
A1 - Bayat, Mohamad
A1 - Hattel, Jesper Henri
T1 - Exploring the Flash Heating method in additive manufacturing for residual stress prediction: A comparative study with diffraction results from X-ray and neutron techniques
N2 - Residual stress (RS) control is crucial for ensuring the performance and reliability of components produced through laser-based powder bed fusion (PBF-LB) additive manufacturing (AM). This study evaluates the Flash Heating (FH) method as an efficient approach for RS prediction, comparing its outcomes with multiple experimental techniques, including X-ray diffraction, neutron diffraction, and layer removal methods. These experimental assessments are conducted in different regions of the component, both before and after detachment from the baseplate. The study validates the FH method and analyzes key numerical parameters, such as meta-layer height, contact time, and time-stepping strategies. Results indicate that FH effectively predicts bulk RS distributions but shows discrepancies in surface stress estimations, likely due to unaccounted factors like surface roughness. Additionally, implementing experimentally derived material properties from as-built AM samples significantly enhances model accuracy compared to conventional material datasets. These findings underscore the potential of FH for efficient RS prediction in PBF-LB while identifying areas for further improvement. Refinements should focus on incorporating anisotropic, temperature-dependent material behavior derived from as-built AM samples and surface roughness effects. This work advances the understanding of key factors necessary for accurate and computationally efficient RS prediction, supporting the optimization of AM processes.
KW - Finete element method
KW - Inconel 718
KW - Metal additive manufacturing
KW - Residual stress
KW - Thermomechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639533
DO - https://doi.org/10.1080/01495739.2025.2541862
SN - 0149-5739
SP - 1
EP - 24
PB - Taylor & Francis
AN - OPUS4-63953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Shiozawa, D.
A1 - Dancette, S.
A1 - Verdu, C.
A1 - Buffiere, J.-Y.
T1 - Torsional fatigue mechanisms of an A357-T6 cast aluminium alloy
N2 - The mechanisms controlling the fatigue response of an A357-T6 cast aluminium alloy under cyclic torsional loading are investigated. Surface crack monitoring coupled with Electron BackScattering Diffraction (EBSD) analysis is used to study crack initiation. Determination of S-N curve combined with interrupted in situ fatigue testing using synchrotron tomography allows the study of the propagation behaviour. It is observed that fractographic morphologies depend on the stress level. At intermediate-low stress levels ( τmax < 100 MPa), the grain structure controls the crack initiation and propagation periods. Cracks are usually nucleated in mode II from slip planes close to the specimen axis or perpendicular to it. Mode II crack growth dominates the early stages of crack propagation as mode III inward crack growth is rapidly decelerated. This behaviour leads to the formation of characteristic shallow surface cracks. Once the crack is long enough for the mode II driving force to be overtaken by mode III, propagation branches into ~45 ◦mode I.
KW - A357-T6 casting
KW - Fractographic observations
KW - EBSD analysis
KW - X-ray synchrotron tomography
KW - Torsional in situ fatigue testing
KW - SIF evaluation
PY - 2020
DO - https://doi.org/10.1016/j.actamat.2020.09.046
VL - 201
SP - 435
EP - 447
PB - Elsevier Ltd.
AN - OPUS4-51461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Dancette, S.
A1 - Verdu, C.
A1 - Buffiere, J.-Y.
T1 - Influence of Pore Size and Crystallography on the Small Crack HCF Behavior of an A357-T6 Cast Aluminum Alloy
N2 - The high-cycle fatigue, small crack propagation behavior of an A357-T6 cast aluminum alloy is investigated. Laboratory X-ray micro-computed tomography (μCT) is used to assist in the manufacturing of two flat fatigue specimens containing subsurface shrinkage pores of different sizes (Pore 1 √A=522μm against Pore 2 √A=280μm). Surface crack monitoring is performed by means of optical microscopy and the cracked specimens are analyzed via scanning electron microscopy and electron backscatter diffraction techniques. The subsurface pores tend to induce intergranular crack nucleation, principally when the grain boundaries are oriented perpendicular to the loading direction. Pore 1 induces a fatigue life reduction of 500.000 cycles when compared to Pore 2. The crystallography is able to influence small crack propagation by slightly decelerating the crack growth rates as well as by altering the crack path topography. Tailoring of the crystallography for improved fatigue resistance requires an investigation of the optimal largest defect to grain size ratio.
KW - A357-T6 cast aluminum alloy
KW - EBSD analysis
KW - Laboratory XµCT
KW - Pore size
KW - Crack initiation period
KW - Crystal plasticity finite element modeling (CPFEM)
PY - 2020
DO - https://doi.org/10.1007/s11661-019-05590-6
SN - 1543-1940
SN - 1073-5623
SP - 1
EP - 12
PB - Springer
AN - OPUS4-50206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erxleben, Kjell
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
A1 - Kannengiesser, Thomas
A1 - Kromm, Arne
T1 - In-service and repair welding of pressurized hydrogen pipelines–a review on current challenges and strategies
N2 - Hydrogen is the energy carrier for a sustainable future without fossil fuels. As this requires a reliable transportation infrastructure, the conversion of existing natural gas (NG) grids is an essential part of the worldwide individual national hydrogen strategies, in addition to newly erected pipelines. In view of the known effect of hydrogen embrittlement, the compatibility of the materials already in use (typically low-alloy steels in a wide range of strengths and thicknesses) must be investigated. Initial comprehensive studies on the hydrogen compatibility of pipeline materials indicate that these materials can be used to a certain extent. Nevertheless, the material compatibility for hydrogen service is currently of great importance. However, pipelines require frequent maintenance and repair work. In some cases, it is necessary to carry out welding work on pipelines while they are under pressure, e.g., the well-known tapping of NG grids. This in-service welding brings additional challenges for hydrogen operations in terms of additional hydrogen absorption during welding and material compatibility. The challenge can be roughly divided into two parts: (1) the possible austenitization of the inner piping material exposed to hydrogen, which can lead to additional hydrogen absorption, and (2) the welding itself causes an increased temperature range. Both lead to a significantly increased hydrogen solubility in the respective materials compared to room temperature. In that connection, the knowledge on hot tapping on hydrogen pipelines is rare so far due to the missing service experiences. Fundamental experimental investigations are required to investigate the possible transferability of the state-of-the-art concepts from NG to hydrogen pipeline grids. This is necessary to ensure that no critical material degradation occurs due to the potentially increased hydrogen uptake. For this reason, the paper introduces the state of the art in pipeline hot tapping, encompassing current research projects and their individual solution strategies for the problems that may arise for future hydrogen service. Methods of material testing, their limitations, and possible solutions will be presented and discussed.
KW - In-service
KW - Hydrogen
KW - Repair welding
KW - Pipeline
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638944
DO - https://doi.org/10.1007/s40194-025-02127-x
SN - 0043-2288
SP - 1
EP - 24
PB - Springer Science and Business Media LLC
AN - OPUS4-63894
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thuy, Maximilian
A1 - Niebergall, Ute
A1 - Oehler, H.
A1 - Alig, I.
A1 - Böhning, Martin
T1 - Evaluation of the damaging effect of crop protection formulations on high density polyethylene using the Full Notch Creep Test
N2 - Four typical high-density polyethylene container materials were used to investigate damage or stress cracking behavior in contact with model liquids for crop protection products. These model liquids are established in German regulations for the approval of dangerous goods containers and consist of typical admixtures used for crop protection products but without biological active ingredients. This study is performed with the standardized method of Full Notch Creep Test, adapting the media temperature to 40 °C according to the usual conditions where these test liquids are applied. The two model liquids differ into a water-based solution and a composition based on different organic solvents which are absorbed by the material up to significant levels. Therefore, extensive sorption measurements are performed. The fracture surfaces obtained are analyzed in detail not only by light microscopy, but also by laser scanning microscopy as well as scanning electron microscopy. Influence of pre-saturation and applied stress are addressed by respective systematic series of experiments.
KW - Polyethylene
KW - Full Notch Creep Test
KW - Environmental Stress Cracking
KW - Fracture
PY - 2021
DO - https://doi.org/10.1016/j.polymer.2021.123853
SN - 0032-3861
VL - 228
SP - 123853
PB - Elsevier Ltd.
AN - OPUS4-52686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Böhning, Martin
T1 - Environmental Stress Cracking in PE-HD – Assessment of Crack Propagation and Mechanisms by Optical Methods
N2 - Slow crack growth (SCG) under the influence of external fluid media, usually termed environmental stress cracking (ESC), is still one of the most frequent origins of severe damage and failure of polymeric materials. For polyethylene (PE) this is relevant for mass products, like bottles for consumer products, but also for high-performance materials for pipes or industrial packaging, including containers for chemicals and other dangerous goods. Especially for high-density polyethylene (PE-HD) the susceptibility to SGC and ESC is depending on the complex interplay between molecular weight and architecture and the resulting semicrystalline morphology, especially the formation of tie-molecules.
A reliable assessment of the resistance against this damage phenomenon is essential for demanding as well as safety-critical applications and has to take into account suitable testing methodologies and conditions in combination with environmental media reflecting the properties representative for typical fillings and relevant components causing ESC. In this context a better understanding of different influencing factors, such as sorption, swelling or surface activity is necessary together with a detailed characterization of different stages of crack propagation and underlying mechanisms. Therefor well-established testing methods, such as the Full Notch Creep Test (FNCT), were complemented by detailed fracture surface analysis using e.g. LSM and SEM in combination with a time-dependent optical monitoring of the progressing crack growth.
For the crack growth also the ratio of fibrillated craze zone to crack opening is important for the deeper understanding of crack propagation and related material parameters which can be additionally addressed by X-ray computed tomography.
T2 - 34th Polymer Degradation Disscussion Group (PDDG) Conference
CY - Dubrovnik, Croatia
DA - 12.06.2023
KW - Polyethylen
KW - Full Notch Creep Test
KW - Environmental Stress Cracking
KW - Fracture Surface Analysis
PY - 2023
AN - OPUS4-57711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kern, Simon
A1 - Liehr, Sascha
A1 - Wander, Lukas
A1 - Bornemann-Pfeiffer, Martin
A1 - Müller, S.
A1 - Maiwald, Michael
A1 - Kowarik, Stefan
T1 - Artificial neural networks for quantitative online NMR spectroscopy
N2 - Industry 4.0 is all about interconnectivity, sensor-enhanced process control, and data-driven systems. Process analytical technology (PAT) such as online nuclear magnetic resonance (NMR) spectroscopy is gaining in importance, as it increasingly contributes to automation and digitalization in production. In many cases up to now, however, a classical evaluation of process data and their transformation into knowledge is not possible or not economical due to the insufficiently large datasets available. When developing an automated method applicable in process control, sometimes only the basic data of a limited number of batch tests from typical product and process development campaigns are available. However, these datasets are not large enough for training machine-supported procedures. In this work, to overcome this limitation, a new procedure was developed, which allows physically motivated multiplication of the available reference data in order to obtain a sufficiently large dataset for training machine learning algorithms. The underlying example chemical synthesis was measured and analyzed with both application-relevant low-field NMR and high-field NMR spectroscopy as reference method. Artificial neural networks (ANNs) have the potential to infer valuable process information already from relatively limited input data. However, in order to predict the concentration at complex conditions (many reactants and wide concentration ranges), larger ANNs and, therefore, a larger Training dataset are required. We demonstrate that a moderately complex problem with four reactants can be addressed using ANNs in combination with the presented PAT method (low-field NMR) and with the proposed approach to generate meaningful training data.
KW - Online NMR spectroscopy
KW - Real-time process monitoring
KW - Artificial neural networks
KW - Automation
KW - Process industry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507508
DO - https://doi.org/10.1007/s00216-020-02687-5
SN - 1618-2642
VL - 412
IS - 18
SP - 4447
EP - 4459
PB - Springer
CY - Berlin
AN - OPUS4-50750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Kern, Simon
A1 - Liehr, Sascha
A1 - Wander, Lukas
A1 - Bornemann-Pfeiffer, Martin
A1 - Müller, S.
A1 - Maiwald, Michael
A1 - Kowarik, Stefan
T1 - Training data of quantitative online NMR spectroscopy for artificial neural networks
N2 - Data set of low-field NMR spectra of continuous synthesis of nitro-4’-methyldiphenylamine (MNDPA). 1H spectra (43 MHz) were recorded as single scans.
Two different approaches for the generation of artificial neural networks training data for the prediction of reactant concentrations were used: (i) Training data based on combinations of measured pure component spectra and (ii) Training data based on a spectral model.
Synthetic low-field NMR spectra
First 4 columns in MAT-files represent component areas of each reactant within the synthetic mixture spectrum.
Xi (“pure component spectra dataset”)
Xii (“spectral model dataset”)
Experimental low-field NMR spectra from MNDPA-Synthesis
This data set represents low-field NMR-spectra recorded during continuous synthesis of nitro-4’-methyldiphenylamine (MNDPA). Reference values from high-field NMR results are included.
KW - NMR spectroscopy
KW - Real-time process monitoring
KW - Artificial neural networks
KW - Online NMR spectroscopy
KW - Automation
KW - Process industry
PY - 2020
DO - https://doi.org/10.5281/zenodo.3677139
PB - Zenodo
CY - Geneva
AN - OPUS4-50456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - High-resolution optical spectrometry for lithium isotope ratio analysis
N2 - An alternative method for lithium isotope amount ratio analysis is proposed by combining atomic absorption spectrometry with spectra data analysis by machine leaning. It is based on the well-known isotope shift of around 15 pm for the electronic transition at wavelength 670.7845 nm which can be measured by a high-resolution continuum source atomic absorption spectrometer (HR-CS-AAS). For isotope amount ratio analysis, a scalable three boosting machine learning algorithm (XGBoost) was employed and calibrated with a set of samples with a 6Li isotope amount fraction ranging from 99% to 6%. The absolute Li isotope amount fractions of these calibration samples were previously measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and used as ab-initio data for the machine learning algorithm. Validation of the machine leaning model was performed with two standard reference materials (LSVEC and IRMM-016). The procedure was employed for the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, LiOH, and LiF) as well as a BAM candidate LiMNC cathode reference material. Achieved uncertainties are one order of magnitude higher than those obtained by MC-ICP-MS. This precision and accuracy is nonetheless sufficient to resolve natural occurring variations in Lithium isotope ratios. Also, the LiMNC material was analyzed by HR-CS-AAS with and without matrix purification. The results are comparable within statistical error.
T2 - Groupseminar - GFZ Potsdam
CY - Online Meeting
DA - 27.10.2020
KW - Lithium batteries
KW - HR-CS-AAS
KW - Machine learning
KW - Isotope analysis
PY - 2020
AN - OPUS4-51572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Chi-Long
A1 - Seeger, Stefan
T1 - Measurement of sub-4 nm particle emission from FFF-3D printing with the TSI Nano Enhancer and the Airmodus Particle Size Magnifier
N2 - The emission of ultrafine particles from small desktop Fused Filament Fabrication (FFF) 3D printers has been frequently investigated in the past years. However, the vast majority of FFF emission and exposure studies have not considered the possible occurrence of particles below the typical detection limit of Condensation Particle Counters and could have systematically underestimated the total particle emission as well as the related exposure risks. Therefore, we comparatively measured particle number concentrations and size distributions of sub-4 nm particles with two commercially available diethylene glycol-based instruments – the TSI 3757 Nano Enhancer and the Airmodus A10 Particle Size Magnifier. Both instruments were evaluated for their suitability of measuring FFF-3D printing emissions in the sub-4 nm size range while operated as a particle counter or as a particle size spectrometer. For particle counting, both instruments match best when the Airmodus system was adjusted to a cut-off of 1.5 nm. For size spectroscopy, both instruments show limitations due to either the fast dynamics or rather low levels of particle emissions from FFF-3D printing in this range. The effects are discussed in detail in this article. The findings could be used to implement sub-4 nm particle measurement in future emission or exposure studies, but also for the development of standard test protocols for FFF-3D printing emissions.
KW - Air pollution
KW - Ultrafine particles
KW - Sub-4nm particles
KW - FFF-3D printing
KW - Emission testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595952
DO - https://doi.org/10.1080/02786826.2024.2320430
SN - 0278-6826
VL - 58
IS - 6
SP - 644
EP - 656
PB - Taylor & Francis
CY - London
AN - OPUS4-59595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Chi-Long
A1 - Seeger, Stefan
A1 - Röllig, Mathias
T1 - Improving the comparability of FFF-3D printing emission data by adjustment of the set extruder temperature
N2 - Fused filament fabrication (FFF) is a material extrusion-based technique often used in desktop 3D printers. Polymeric filaments are melted and are extruded through a heated nozzle to form a 3D object in layers. The extruder temperature is therefore a key parameter for a successful print job but also one of the main emission driving factors as harmful pollutants (e.g., ultrafine particles) are formed by thermal polymer degradation. The awareness of potential health risks has increased the number of emission studies in the past years. However, studies usually refer their calculated emission data to the printer set extruder temperature for comparison purposes. In this study, we used a thermocouple and an infrared camera to measure the actual extruder temperature and found significant temperature deviations to the displayed set temperature among printer models. Our result shows that printing the same filament feedstocks with three different printer models and with identical printer set temperature resulted in a variation in particle emission of around two orders of magnitude. A temperature adjustment has reduced the variation to approx. one order of magnitude. Thus, it is necessary to refer the measured emission data to the actual extruder temperature as it poses a more accurate comparison parameter for evaluation of the indoor air quality in user scenarios or for health risk assessments.
KW - Ultrafine particles
KW - Infrared thermography
KW - Thermocouple
KW - Indoor air quality
KW - FFF-3D printer
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572842
DO - https://doi.org/10.1016/j.aeaoa.2023.100217
VL - 18
SP - 100217
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-57284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Stephan, D.
A1 - Ostermann, Markus
A1 - Possolo, A.
A1 - Vogl, Jochen
T1 - Fingerprinting Portland cements by means of 87Sr/86Sr and 143Nd/144Nd isotope ratios and geochemical profiles
N2 - This study uses conventional 87Sr/86Sr and 143Nd/144Nd isotope and interelement ratios of Ca, Sr, K, Mn, Mg and Ti as fingerprints for provenancing ordinary Portland cements (OPC). Herein, the first database of Sr and Nd isotope ratios investigated in OPCs, stemming from 29 cement plants located worldwide, was created. The results show that the Sr isotope ratios of OPCs are higher than those of seawater from the observed geological period. The spread of 143Nd/144Nd in OPCs is not as large as the spread for 87Sr/86Sr isotope ratios. However, the combination of both Sr and Nd isotope ratios provides the potential for distinguishing between cements of different production sites. Most of the OPCs investigated have measurable differences in their 87Sr/86Sr and 143Nd/144Nd isotope ratios, which can be employed as a valuable analytical fingerprinting tool. In the case of equivocal results, divisive hierarchical clustering was employed to help overcome this issue. The construction of geochemical profiles allowed the computing of suitably defined distances between cements and clustering them according to their chemical similarity. By applying this methodology, successful fingerprinting was achieved in 27 out of the 29 ordinary Portland cements that were analysed.
KW - Elemental fingerprints
KW - Geochemistry
KW - Portland cement
KW - Sr and Nd isotope analysis
KW - Statistical analysis
PY - 2023
DO - https://doi.org/10.1680/jadcr.23.00018
SN - 0951-7197
VL - 36
IS - 6
SP - 260
EP - 271
PB - Emerald Publishing Limited
AN - OPUS4-57979
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tang, Chi-Long
T1 - Minimizing the FFF-3D printer hardware bias on particle emission by adjustment of the set extruder temperature
N2 - Fused filament fabrication (FFF) on desktop 3D printers is a material extrusion-based technique often used by educational institutions, small enterprises and private households. Polymeric filaments are melted and extruded through a heated nozzle to form a 3D object in layers. The extrusion temperature is therefore a key parameter for a successful print job, but also one of the main driving factors for the emission of harmful air pollutants, namely ultrafine particles and volatile organic gases, which are formed by thermal stress on the polymeric feedstock. The awareness of potential health risks has increased the number of emission studies in the past years. However, the multiplicity of study designs makes an objective comparison of emission data challenging because printer hardware factors such as the actual extruder temperature (TE) and also feedstockspecific emissions are not considered. We assume that across the market of commercial low- and mid-price FFF printers substantial deviations between actual and set extruder temperatures exist, which have a strong effect on the emissions and hence may bias the findings of exposure studies. In our last publication, we presented a standardized feedstock-specific emission test method and showed that for each investigated feedstock an increase in actual extruder temperature was accompanied by an increase in particle emissions (Tang and Seeger, 2022). Therefore, any systematic discrepancy between set and actual extruder temperature matters. In this study, we used a thermocouple and an infrared camera to measure the actual extruder temperatures at different heights. We found significant under- and overestimation of the actual extruder temperatures by the respective set temperatures in three commercial printers. This caused a broad variation of the measured total numbers of emitted particles (TP), even when the same feedstock was operated. For the determination of TP, we followed the DE-UZ 219 test guideline. In a second round we repeated the tests with all printers adjusted to exactly the same extruder temperatures, i.e., to TE=230°C for ABS and TE=210°C for PLA. All measurements were conducted in a 1 m³ emission test chamber. Particle emissions in the size range between 4 nm and 20 μm were detected. Printing on three different printer models without temperature adjustment resulted for each of the investigated feedstocks in a variation in TP of around two orders of magnitude. After temperature adjustment, this was substantially reduced to approx. one order of magnitude and hence minimizes the bias of printer hardware on the emissions. Our findings suggest that adjustment of the extruder temperature should be mandatory in emission testing standards. It also poses a more accurate benchmark and provides more reliable emission data for evaluation of indoor air quality or for health risk assessments. In addition, a proper temperature setting is in the interest of the user. Some commercial FFF printers may have a higher actual extruder temperature than displayed and unintended overheating may not only impair the print quality but may cause unnecessarily increased exposure to particle emissions.
T2 - European Aerosol Conference 2023
CY - Málaga, Spain
DA - 03.09.2023
KW - Ultrafine particles
KW - Thermal imaging
KW - 3D printing
KW - Indoor air quality
KW - Emission testing
PY - 2023
AN - OPUS4-58258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Why do I have to charge my phone twice a day?
N2 - Aging Mechanisms of Lithium Batteries: How can we make batteries more durable and more sustainable in the future?
Lithium batteries are particularly susceptible to ageing processes. During each charging and discharging process in an electric battery, lithium ions are deposited in the electrodes of the cell like in the pores of a sponge. Over time, however, fractures and cracks occur in the filigree structures. The result: more and more lithium ions no longer fit into the hollow spaces of the „sponge“, instead they accumulate in heaps around the electrodes and hinder the movement of other ions. The performance of the battery decreases.
We present our new project, in which we are developing a fast and cost-effective method with which companies that produce lithium batteries can already assess the ageing behaviour of their batteries in the laboratory.
T2 - Berlin Science Week 2022
CY - Online meeting
DA - 10.11.2022
KW - Lithium Ion Batteries
KW - Aging Mechanisms
PY - 2022
UR - https://berlinscienceweek.com/de/event/why-do-i-have-to-charge-my-phone-twice-a-day/
UR - https://www.youtube.com/watch?v=bF7bQTY49rQ
AN - OPUS4-56245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baynosa, M. L.
A1 - Mady, A. H.
A1 - Nguyen, V. Q.
A1 - Kumar, D. R.
A1 - Sayed, M. S.
A1 - Tuma, Dirk
A1 - Shim, J.-J.
T1 - Eco-friendly synthesis of recyclable mesoporous zinc ferrite@reduced graphene oxide nanocomposite for efficient photocatalytic dye degradation under solar radiation
N2 - Zinc ferrite and graphene composites have attracted considerable attention in wastewater treatment. In this work, a magnetically separable mesoporous composite of ZnFe2O4 nanoparticles (NPs) and reduced graphene oxide (rGO) was prepared through a simple and eco-friendly method with pure water as solvent and without the need for subsequent thermal treatment. Uniformly dispersed ZnFe2O4 NPs on the surface of rGO sheets exhibited good crystallinity and a large BET specific surface area. These factors contributed to good photocatalytic performance of the composite for the degradation of methylene blue (MB) under simulated solar-light radiation, increased adsorptivity, increased separation efficiency of the photo-excited charges on the surface of the catalyst, and broadened light-absorption range of the composite. Efficient interfacial interaction between the ZnFe2O4 NPs and rGO sheets resulted in synergistic effects. The magnetically separable ZnFe2O4@rGO nanocomposite proved an efficient and stable catalyst in three consecutive photodegradation cycles for MB dye in aqueous solution under solar radiation. In addition, the synthesis method proposed in this study could be scaled-up easily due to the simplicity of the process, the lack of a toxic reagent, and the use of low temperatures.
KW - Zinc ferrite
KW - Reduced graphene oxide
KW - Nanocomposite
KW - Wastewater
PY - 2020
DO - https://doi.org/10.1016/j.jcis.2019.11.018
SN - 0021-9797
VL - 561
SP - 459
EP - 469
PB - Elsevier B. V.
CY - Amsterdam
AN - OPUS4-50211
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dahmen, N.
A1 - Deiters, U. K.
A1 - Tuma, Dirk
T1 - In Memoriam - Professor Dr. rer. nat. Gerhard Manfred Schneider (May 7, 1932 - October 16, 2020) - Professor and Chair of Physical Chemistry, Ruhr-University, Bochum, Germany (1969-1997)
N2 - Professor Gerhard Schneider, a truly dedicated researcher, teacher, and pioneer in the field of high-pressure science, passed away on October 16th, 2020. It is with deep gratitude that we remember him here.
KW - Obituary
KW - Physical Chemistry
KW - Phase Equilibria
PY - 2021
DO - https://doi.org/10.1016/j.supflu.2021.105219
SN - 0896-8446
VL - 174
SP - 1
EP - 2
PB - Elsevier
CY - Amsterdam
AN - OPUS4-52457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Shiflett, M. B.
A1 - Magee, J. W.
A1 - Tuma, Dirk
ED - Shiflett, M. B.
T1 - Important Developments in the History of Ionic Liquids from Academic Curiosity to Commercial Processes and Products
N2 - Twenty years ago, research involving ionic liquids was a minor field of interest, and only a few chemists and even fewer engineers were interested in salts with melting points near room temperature. In April 2000, the first NATO advanced research workshop on ionic liquids was held in Heraklion, Crete. The conference was the first international meeting devoted to ionic liquids and attracted most of the active researchers at that time. Following that meeting, activity in the field began to flourish and the first books and international conferences devoted to ionic liquids began to appear. By the end of 2018, more than 80,000 scientific papers had been published, and 17,000 patents were applied for in the field of ionic liquids! This book provides an overview of the current and emerging industrial applications of ionic liquids covering the core processes and products, the practical implementation and technical challenges involved, and the potential future directions for Research and development. The individual chapters were written by leading scientists in the field from industry and academia to address specific processes and products that are or will be soon commercialized. Examples include the use of a chloroaluminate ionic liquid as a next-generation alkylation catalyst to a new class of capillary gas chromatography (GC) columns with stationary phases based on ionic liquids. Over the past twenty years, there has been a growing realization that ionic liquids have moved from being mere academic curiosities to having genuine applications in fields as wide-ranging as advanced materials, biotechnology, catalysis, pharmaceuticals, renewable fuels, and sustainable energy. There are many optimistic indications that ionic liquids are on their way to becoming a commercial success story. This first book on “Commercial Applications of Ionic Liquids” provides over 50 applications that are either at the pilot scale or have been commercialized, which indicates that an exciting new chapter in the field of ionic liquids is about to begin!
KW - Ionic Liquids
KW - Historical Developments
KW - Advanced Materials
PY - 2020
SN - 978-3-030-35245-5
DO - https://doi.org/10.1007/978-3-030-35245-5_1
SN - 2196-6990
SP - 3
EP - 29
PB - Springer
CY - Cham
AN - OPUS4-50453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Sommer, Konstantin
A1 - Knobloch, Tim
A1 - Altenburg, Simon
A1 - Recknagel, Sebastian
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
T1 - Process Induced Preheating in Laser Powder Bed Fusion Monitored by Thermography and Its Influence on the Microstructure of 316L Stainless Steel Parts
N2 - Undetected and undesired microstructural variations in components produced by laser powder bed fusion are a major challenge, especially for safety-critical components. In this study, an in-depth analysis of the microstructural features of 316L specimens produced by laser powder bed fusion at different levels of volumetric energy density and different levels of inter layer time is reported. The study has been conducted on specimens with an application relevant build height
(>100 mm). Furthermore, the evolution of the intrinsic preheating temperature during the build-up of specimens was monitored using a thermographic in-situ monitoring set-up. By applying recently determined emissivity values of 316L powder layers, real temperatures could be quantified. Heat accumulation led to preheating temperatures of up to about 600 °C. Significant differences in the preheating temperatures were discussed with respect to the individual process parameter combinations, including the build height. A strong effect of the inter layer time on the heat accumulation was observed. A shorter inter layer time resulted in an increase of the preheating temperature by more than a factor of 2 in the upper part of the specimens compared to longer inter layer times. This, in turn, resulted in heterogeneity of the microstructure and differences in material properties within individual specimens. The resulting differences in the microstructure were analyzed using electron back scatter diffraction and scanning electron microscopy. Results from chemical analysis as well as electron back scatter diffraction measurements indicated stable conditions in terms of chemical alloy composition and austenite phase content for the used set of parameter combinations. However, an increase of the average grain size by more than a factor of 2.5 could be revealed within individual specimens. Additionally, differences in feature size of the solidification cellular substructure were examined and a trend of increasing cell sizes was observed. This trend was attributed to differences in solidification rate and thermal gradients induced by differences in scanning velocity and preheating temperature. A change of the thermal history due to intrinsic preheating could be identified as the main cause of this heterogeneity. It was induced by critical combinations of the energy input and differences in heat transfer conditions by variations of the inter layer time. The microstructural variations were directly correlated to differences in hardness.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - In-situ process monitoring
KW - Thermography
KW - Heat accumulation
KW - Inter layer time
KW - Cellular substructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529240
DO - https://doi.org/10.3390/met11071063
VL - 11
IS - 7
SP - 1063
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-52924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iqbal, S.
A1 - Mady, A. H.
A1 - Kim, Y.-I.
A1 - Javed, U.
A1 - Shafi, P. M.
A1 - Nguyen, V. Q.
A1 - Hussain, I.
A1 - Tuma, Dirk
A1 - Shim, J.-J.
T1 - Self-templated hollow nanospheres of B-site engineered non-stoichiometric perovskite for supercapacitive energy storage via anion-intercalation mechanism
N2 - The continual increase in energy demand and inconsistent supply have attracted attention towards sustainable energy storage/conversion devices, such as electrochemical capacitors with high energy densities and power densities. Perovskite oxides have received significant attention as anion-intercalation electrode materials for electrochemical capacitors. In this study, hollow nanospheres of nonstoichiometric cubic perovskite fluorides, KNi1-xCoxF3-delta (x = 0.2; delta = 0.33) (KNCF-0.2) have been synthesized using a localized Ostwald ripening. The electrochemical performance of the non-stoichiometric perovskite has been studied in an aqueous 3 M KOH electrolyte to categorically investigate the fluorine-vacancy-mediated charge storage capabilities. High capacities up to 198.55 mA h g-1 or 714.8 C g-1 (equivalent to 1435 F g-1) have been obtained through oxygen anion-intercalation mechanism (peroxide pathway, O-). The results have been validated using ICP (inductively coupled Plasma mass spectrometry) analysis and cyclic voltammetry. An asymmetric supercapacitor device has been fabricated by coupling KNCF-0.2 with activated carbon to deliver a high energy density of 40 W h kg-1 as well as excellent cycling stability of 98 % for 10,000 cycles. The special attributes of hollow-spherical, non-stoichiometric perovskite (KNCF-0.2) have exhibited immense promise for their usability as anion-intercalation type electrodes in supercapacitors.
KW - Nanospheres
KW - Perovskite
KW - Supercapacitor
PY - 2021
DO - https://doi.org/10.1016/j.jcis.2021.03.147
SN - 0021-9797
VL - 600
SP - 729
EP - 739
PB - Elsevier Inc.
CY - Amsterdam
AN - OPUS4-52873
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Advantages of N2-MICAP-MS for Trace Metal Analysis in Steel
N2 - The climate and energy crisis are extreme challenges. One possible solution could be hydrogen technology. Safety is a big concern. Steel used for pipelines and storage is under permanent stress from low temperatures and high pressures. The content of different alloyed metals determines the performance of the steel. Nitrogen microwave inductively coupled atmosphere pressure plasma mass spectrometry (N2-MICAP-MS) is a promising method for trace metal analysis in steel. Nitrogen is cheap and can be generated on site. It has fewer interferences than argon. Additionally, MICAP-MS is very matrix tolerant, proving the matrix-matched calibration expendable. Safety in technology and chemistry is the mission of BAM. Providing reference methods and materials can create trust in future technologies like hydrogen.
T2 - SALSA Make and Measure 2022
CY - Berlin, Germany
DA - 15.09.2022
KW - Trace analysis
KW - Steel
KW - Microwave plasma
KW - Mass spectrometry
KW - Safety
PY - 2022
AN - OPUS4-55792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Liehr, Sascha
T1 - ANNforPAT - Artificial Neural Networks for Process Analytical Technology
N2 - This code accompanies the paper "Artificial neural networks for quantitative online NMR spectroscopy" published in Analytical and Bioanalytical Chemistry (2020).
KW - Artificial neural networks
KW - Automation
KW - Online NMR spectroscopy
KW - Process industry
KW - Real-time process monitoring
PY - 2020
UR - https://github.com/BAMresearch/ANNforPAT
PB - GitHub
CY - San Francisco
AN - OPUS4-54481
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tuma, Dirk
A1 - Moreau, A.
A1 - Polishuk, I.
A1 - Segovia, J. J.
A1 - Vega-Maza, D.
A1 - Martín, M. C.
T1 - Measurements and predictions of densities and viscosities in CO2 + hydrocarbon mixtures at high pressures and temperatures: CO2 + n-pentane and CO2 + n-hexane blends
N2 - This work reports new experimental data on densities and viscosities of (CO2 + n-pentane) and (CO2 + n-hexane) mixtures at high pressures and temperatures. The densities were measured by a vibrating-tube densimeter with an expanded uncertainty (k = 2) smaller than 1.8 kg/m3 at six isotherms (from 273.15 K to 373.15 K), twelve pressures starting at 5 MPa up to 100 MPa, and at six CO2 molar compositions (from 0 to 0.6). The viscosities were measured by a vibrating-wire viscometer with the corresponding relative expanded uncertainty (k = 2) smaller than 0.016 at five isotherms (from 273.15 K to 373.15 K), twelve pressures (from 5 MPa up to 100 MPa), and at two CO2 molar compositions (0.1 and 0.3). The densities were fitted by the semiempirical Tammann-Tait equation for density data and the Vogel-Fulcher-Tammann (VFT) equation for viscosity data, respectively. The Groupe Européen de Recherches Gazières (GERG-2008) equation of state was also applied for modelling the densities. Over-all robustness and reliability of the Perturbed-Chain Statistical Association Fluid Theory (PC-SAFT) and its critical point-based modification (CP-PC-SAFT) were examined. Accuracies of the Modified Yarranton-Satyro (MYS) coupled with CP-PC-SAFT and the NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP 10) in predicting the viscosities were evaluated.
KW - CO2 + n-alkanes
KW - thermophysical properties
KW - Perturbed-Chain Statistical Association Fluid Theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555728
DO - https://doi.org/10.1016/j.molliq.2022.119518
SN - 0167-7322
VL - 360
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
ED - Tuma, Dirk
ED - Weide, T.
ED - Rasmusson, H.
T1 - MefHySto - Metrology for advanced hydrogen storage solutions
N2 - The “Metrology for Advanced Hydrogen Storage Solutions” (MefHySto) project is a European initiative addressing the need for large-scale energy storage solutions, that is crucial for the successful transition to renewable energy sources. The main objective of this project was to develop and provide metrological standards and validated techniques for the storage and utilization of hydrogen. Hydrogen is increasingly recognized as an important component in the future energy system due to its ability to store and supply energy during peak demand periods when renewable sources, such as solar and wind, are not generating power.
KW - Water electrolysis
KW - Thermophysical properties
KW - Fuel cell
KW - Hydrogen storage
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625952
DO - https://doi.org/10.5281/zenodo.12684898
SP - 1
EP - 40
PB - ERIG European Research Institute for Gas and Energy Innovation a.i.s.b.l.
CY - Bruxelles
AN - OPUS4-62595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Advanced spectroscopic methods for fluorine microanalysis in lithium-ion batteries
N2 - To address the challenges of the climate crisis, multiple solutions for sustainable energy sources and storage systems are needed. One such solution is lithium-ion batteries (LIBs). Currently, 5 to 30 % of LIBs are discarded immediately after manufacturing. The homogeneous distribution of all materials used in the coating of cathodes and anodes is critical for the quality of LIBs. Furthermore, during formation i.e., the first steps of the charge/discharge cycling, the solid-electrolyte interphase forms on the anode particles, which has a huge impact on the performance. The same happens to some extent on the cathode, forming the cathode-electrolyte interphase. Fluorinated polymers and electrolytes are used in the manufacturing of LIBs. The electrolyte in particular is prone to degradation during formation and aging of the batteries. The interface of the cathode material with the aluminum current collector is also a critical point where degraded fluorine components cause pitting corrosion and at the same time promote passivation of the metal foil. Monitoring the spatial distribution of fluorine on these surfaces and interfaces is essential for sustainable LIB production.
T2 - SALSA Kick-Off Meeting
CY - Berlin, Germany
DA - 11.04.2024
KW - Lithium Ion Batteries
KW - solid microanalysis
KW - depth-profiling
KW - fluorine
PY - 2024
AN - OPUS4-60199
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Safarov, J.
A1 - Tuma, Dirk
A1 - Müller, K.
T1 - Thermophysical properties of the paramagnetic ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate over an extended range of temperature and pressure
N2 - The paramagnetic ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate [BMIM][FeCl4] was subject to multiple high-precision thermophysical property measurements under both ambient and high pressure. Density rho(p0,T) / kg m-3 and speed of sound u(p0,T) / m s-1 data at ambient pressure were recorded at temperatures T = (278.15 to 343.16) K using a DSA 5000 M combined vibrating tube densimeter and speed of sound analyser with a standard uncertainty of delta rho(p0,T) = ±0.001 kg m-3 and delta u(p0,T) = ±0.1 m s-1, respectively. High-pressure volumetric (p,rho,T) data were measured on an Anton Paar DMA HPM vibrating tube densimeter at T = (273.16 to 413.15) K and at pressures up to p = 140 MPa with an estimated experimental relative combined average percentage deviation (APD) of delta rho(p,T) / rho(p,T) = ±(0.01 to 0.08) %.
The specific isobaric heat capacity cp(p0,T) / J kg-1 K-1, a caloric property, was determined at T = (273.15 to 413.15) K with an uncertainty delta cp / cp = ±0.5 % using a Perkin Elmer Pyris 1 DSC differential scanning calorimeter. To gain knowledge of transport properties, the dynamic viscosity eta(p0,T) / mPa s at ambient pressure was recorded at T = (275.03 to 413.18) K by an Anton Paar SVM 3000 Stabinger viscometer and additionally an Anton Paar rheometer MCR 302 device with uncertainties of delta eta / eta = ±0.35 % and delta eta / eta = ±1 %, respectively.
The obtained data were first correlated by empirical polynomial equations of state and further processed by the application of classic thermodynamic potentials to determine isothermal compressibility kappa T(p,T) / MPa-1, isobaric thermal expansivity alpha p(p,T) / K-1, thermal pressure coefficient gamma(p,T) / MPa K-1, internal pressure pint(p,T) / MPa, specific heat capacity at constant pressure cp(p,T) / J kg-1 K-1 and at constant volume cv(p,T) / J kg-1 K-1, the difference of isobaric and isochoric heat capacity (cp–cv)(p,T) / J kg-1 K-1, speed of sound u(p,T) / m s-1 and ultimately isentropic exponent kappa s(p,T).
This work extends knowledge about the thermophysical properties of [BMIM][FeCl4] particularly to high temperatures and pressures.
KW - Ionic liquid
KW - Volumetric properties
KW - Transport properties
KW - Caloric properties
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2021.117939
SN - 0167-7322
VL - 346
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tuma, Dirk
A1 - Shafi, P. M.
A1 - Mohapatra, D.
A1 - Reddy, V. P.
A1 - Dhakal, G.
A1 - Kumar, D. R.
A1 - Brousse, T.
A1 - Shim, J.-J.
T1 - Sr- and Fe-substituted LaMnO3 Perovskite: Fundamental insight and possible use in asymmetric hybrid supercapacitor
N2 - The symmetry or structural stability of ABO3-type perovskite oxides depends largely on the size of ‘A’ and ‘B’ cations, which determines the material properties. The partial substitution of these cations may be used to tune these properties. The ionic sizes and valence states of the cations play an important role in improving the prop- erties of perovskite. In this study, the substitution of La3+ with Sr2+ with a larger ionic radius and Mn3+ with Fe3+ with a similar ionic radius favored both the crystal symmetry and the mixed ionic–electronic conductivity of the perovskite. Electrodes based on La0.7Sr0.3Mn0.5Fe0.5O3 (LSMFO55) exhibited a faradaic behavior with a specific capacity of 330 C g−1 (92 mAh g−1 ) at 12C rate, while this electrode maintained a capacity of 259 C g−1 at 240C (charge or discharge in 15 s). Additionally, exohedral carbon nano-onions (CNO) were introduced as a negative electrode to design an asymmetric hybrid supercapacitor (AHS) with a widened cell voltage. The use of CNO as a negative electrode in the AHS improved the rate capability drastically compared to the use of rGO. This device maintained a good energy density even at an extra-high charging rate (600C) owing to its outstanding rate capability. The high-rate performance of the LSMFO55//CNO AHS can be elucidated by successful fabrication with a mixed ionic–electronic conductive positive electrode and a CNO negative electrode. Tuning the electronic and ionic conductivities by cationic substitution and adopting an appropriate carbon-derived negative electrode (such as CNO) can provide a practical high-rate hybrid device using various perovskites.
KW - Perovskite
KW - Carbon nano-onion
KW - Supercapacitor
PY - 2022
DO - https://doi.org/10.1016/j.ensm.2021.11.028
SN - 2405-8297
VL - 45
SP - 119
EP - 129
PB - Elsevier B. V.
CY - Amsterdam
AN - OPUS4-54882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eshetie Kidie, A.
A1 - Dhakal, G.
A1 - Sahoo, S.
A1 - Tuma, Dirk
A1 - Shim, J.-J.
T1 - Interlayer spacing-controlled carnation flower-like microstructure of nickel-manganese layered double hydroxide for enhancing hybrid supercapacitor performance
N2 - Energy harvested from intermittent sources can be stored in supercapacitors for high-power delivery with long cycling stability. Binary layered double hydroxide (LDH) materials have great potential for hybrid supercapacitor applications owing to their mixed and tunable charges and layered structure. This study presents carnation flower-like, 3D micro-structured NiMn-LDH prepared by a facile single-step hydrothermal synthesis using hexamethylenetetramine to produce hydroxides. The 3D structure was assembled from ultrathin 2D NiMn-LDH nanosheets, and the largest interlayer spacing was obtained by optimizing synthesis parameters, such as Ni:Mn molar ratio and reaction temperature, ensuring a fast diffusion and thus the best energy storage performance. The optimized NiMn-LDH electrode delivered a high specific capacity of 612 C/g with an excellent rate capability of 67% at 20 A/g in a three-electrode test. An asymmetric device assembled using NiMn-LDH and reduced graphene oxide as positive and negative electrodes provided a high energy density of 60.0 Wh/kg and power density of 17.7 kW/kg with 90.4% capacity retention after 10,000 charge–discharge cycles. This superior result highlights the potential industrial applications, such as portable electronics and trams.
KW - Supercapacitor
KW - Hydrothermal synthesis
KW - Interlayer spacing
PY - 2024
DO - https://doi.org/10.1016/j.jiec.2023.12.032
SN - 1226-086X
VL - 133
SP - 550
EP - 560
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-60472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - A numerical study on the suppression of a detrimental weld pool profile in wire feed laser beam welding by MHD technique
N2 - The weld quality and the possible defect formation are directly determined by the weld pool shape and the thermo-fluid dynamics therein. In this paper, an untypical weld pool profile, i.e., elongated at its top and bottom but narrowed at the middle, is found experimentally and numerically in the wire feed laser beam welding. The detrimental influence of the weld pool narrowing on the element transport is analyzed and discussed. A magnetohydrodynamic technique is utilized to suppress the narrowing, aiming at a more homogenous element distribution. It is found that a low-temperature region is formed in the middle of the weld pool due to the interaction of the two dominant circulations from the top and bottom regions. The weld pool is significantly narrowed due to the untypical growth of the mushy zone in the low-temperature region, which results in a direct blocking effect on the downward flow and the premature solidification in the middle region. The Lorentz force produced by a transverse oscillating magnetic field shows the potential to change the flow pattern into a single-circulation type and the low-temperature-gradient region is mitigated. Therefore, the downward transfer channel is widened, and its premature solidification is prevented. The numerical results are well validated by experimental measurements of metal/glass observation and X-ray fluorescence element mapping.
T2 - The 13th International Seminar "Numerical Analysis of Weldability"
CY - Graz, Austria
DA - 04.09.2022
KW - Thermo-fluid flow
KW - Element transport
KW - Laser beam welding
KW - Magnetohydrodynamics
KW - Multi-physical modeling
PY - 2022
AN - OPUS4-55780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - An investigation of keyhole dynamics and porosity mitigation in laser beam welding with external magnetic field
N2 - The macro and micro benefits from a magnetic field have been well recognized in the laser beam welding, but the influence mechanism, especially on the local keyhole dynamics, is yet not fully understood. A combination of experimental approach and numerical modeling was conducted to study the highly transient keyhole dynamics under the magnetic field. It was found that the magnetic field gave a direct impact on the laser energy absorption at the keyhole front wall. The keyhole-induced porosity was suppressed under the influence of the magnetic field, which was confirmed by the micro-X-ray computed tomography. The porosity mitigation comes from multiple physical aspects, including keyhole stabilization, widening of the bubble floating channel, and the electromagnetic expulsive force. The predicted penetration depth and weld pool profiles with/without magnetic field show a good agreement with the experimental measurements, including optical micrographs and in-situ metal/glass observation.
T2 - The 75th IIW Annual Assembly and International Conference
CY - Tokyo, Japan
DA - 17.07.2022
KW - Laser beam welding (LBW)
KW - Keyhole dynamics
KW - Porosity
KW - Magnetic field
KW - Multi-physical modeling
PY - 2022
AN - OPUS4-55781
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Numerical analysis of the dependency of the weld pool shape on turbulence and thermodynamic activity of solutes in laser beam welding of unalloyed steels
N2 - A three-dimensional numerical model was developed to accurately predict the steady-state weld pool shape in full penetration laser beam welding. The model accounts for the coupling between the heat transfer and the fluid dynamics by considering the effects of solid/liquid phase transition, thermo-capillary convection, natural convection, and phase-specific and temperature-dependent material properties up to the evaporation temperature. A fixed right circular cone was utilized as a keyhole geometry to consider the heat absorbed from the laser beam. The model was used to analyze the influence of the thermodynamic activity of solutes and turbulence on the weld pool shape. A mesh sensitivity analysis was performed on a hybrid mesh combining hexahedral and tetrahedral elements. For the case of full penetration laser beam welding of 8 mm thick unalloyed steel sheets, the dependence of the weld pool shape on the surface-active element sulfur was found to be negligible. The analysis of the results showed that a laminar formulation is sufficient for accurately predicting the weld pool shape since the turbulence has a minor impact on the flow dynamics in the weld pool. The validity of the numerical results was backed up by experimental measurements and observations, including weld pool length, local temperature history, and a range of metallographic cross-sections.
T2 - 13th International Seminar Numerical Analysis of Weldability
CY - Seggau, Austria
DA - 04.09.2022
KW - Weld pool shape
KW - Numerical modeling
KW - Laser beam welding
KW - Thermo-capillary convection
KW - Turbulence
PY - 2022
AN - OPUS4-55718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Untersuchung zum Elektronenstrahlschweißen von additiv gefertigtem Inconel 939
N2 - Hochfeste Nickelbasislegierungen wie Inconel 939 spielen eine wesentliche Rolle im modernen Turbinenbau. Additive Fertigungstechnologien eröffnen hierbei neue Möglichkeiten für die Verarbeitung, jedoch fehlen verlässliche Fügeprozesse für die Absicherung der additiven Prozesskette im Bereich Neuteilfertigung und Instandsetzung. Insbesondere Heißrisse stellen eine große Herausforderung an die Fügetechnik. Die vorliegende Untersuchung befasst sich daher mit dem Verhalten von additiv gefertigten Blechen aus Inconel 939 beim Elektronenstrahlschweißen. Es werden grundlegende Zusammenhänge zwischen Prozessparametern, Härte und Rissneigung betrachtet und Ansätze für eine Optimierung auf Basis statistischer Versuchsplanung aufgezeigt. Hierbei erfolgt eine Einteilung der Risse nach bestimmten Nahtbereichen. Risse am Nahtkopf können durch die Faktoren Vorschub und Streckenenergie sowie die Härte des Schweißgutes beeinflusst werden. Risse im Bereich der parallelen Nahtflanken stehen hingegen im Zusammenhang mit der Härte der Wärmeinflusszone. Ein abschließender Vergleich der angepassten Parameter mit der Ausgangssituation zeigt, dass durch Anwendung der statistischen Optimierung eine deutliche Reduzierung der Rissneigung erreicht werden kann.
T2 - 42. Assistentenseminar Fügetechnik
CY - Beverungen, Germany
DA - 06.10.2021
KW - Elektronenstrahlschweißen
KW - Additive Fertigung
KW - Schweißnahtbewertung
PY - 2022
SN - 978-3-96144-210-2
VL - 385
SP - 1
EP - 8
PB - DVS Media GmbH
AN - OPUS4-57320
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simón Muzás, Juan
T1 - Mechanical properties of laser welded joints of wrought and heat treated PBF LB/M Inconel 718 parts depending on build direction
N2 - Laser-based Powder Bed Fusion of Metal (PBF-LB/M) is a broadly used metal additive manufacturing (AM) method for fabricating complex metallic parts, whose sizes are however limited by the build envelope of PBF-LB/M machines. Laser welding arises as a valid joining method for effectively integrating these AM parts into larger assemblies.
PBF-LB/M components must usually be stress-relieved before they can be separated from the build plate. An additional heat treatment can be beneficial for obtaining homogeneous mechanical properties across the seam or for the formation of desired precipitations in nickel-based-alloys.
Therefore, the tensile performance of laser welded hybrid (AM/wrought) and AM-AM tensile samples of Inconel 718 is examined after undergoing three different heat treatments and considering three relevant build directions. It can be shown that the build orientation is an influencing factor on weld properties even after two applied heat treatments.
T2 - Lasers in Manufacturing LiM 2023
CY - Munich, Germany
DA - 26.06.2023
KW - Laser welding
KW - PBF/LB-M
KW - Hybrid components
KW - Heat treatments
KW - Build direction
KW - Tensile performance
KW - Inconel 718
PY - 2023
AN - OPUS4-58016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Manzoni, Anna Maria
A1 - Schneider, M.
A1 - Laplanche, G.
T1 - Welding of high-entropy alloys and compositionally complex alloys - an overview
N2 - High-entropy alloys (HEAs) and compositionally complex alloys (CCAs) represent new classes of materials containing five or more alloying elements (concentration of each element ranging from 5 to 35 at. %). In the present study, HEAs are defined as single-phase solid solutions; CCAs contain at least two phases. The alloy concept of HEAs/CCAs is fundamentally different from most conventional alloys and promises interesting properties for industrial applications (e.g., to overcome the strength-ductility trade-off). To date, little attention has been paid to the weldability of HEAs/CCAs encompassing effects on the welding metallurgy. It remains open whether welding of HEAs/CCAs may lead to the formation of brittle intermetallics and promote elemental segregation at crystalline defects. The effect on the weld joint properties (strength, corrosion resistance) must be investigated. The weld metal and heat-affected zone in conventional alloys are characterized by non-equilibrium microstructural evolutions that most probably occur in HEAs/CCAs. The corresponding weldability has not yet been studied in detail in the literature, and the existing information is not documented in a comprehensive way. Therefore, this study summarizes the most important results on the welding of HEAs/CCAs and their weld joint properties, classified by HEA/CCA type (focused on CoCrFeMnNi and AlxCoCrCuyFeNi system) and welding process.
KW - High-entropy alloy
KW - Compositionally complex alloy
KW - Welding
KW - Properties
KW - Review
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527068
DO - https://doi.org/10.1007/s40194-021-01110-6
SP - 1
EP - 15
PB - Springer Nature
AN - OPUS4-52706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, M.
A1 - Diercks, P.
A1 - Manzoni, Anna Maria
A1 - Čížek, J.
A1 - Ramamurty, U.
A1 - Banhart, J.
T1 - Positron annihilation investigation of thermal cycling induced martensitic transformation in NiTi shape memory alloy
N2 - Thermal cycling of a Ni-excess NiTi alloy was conducted between 50 °C and liquid nitrogen temperature to induce martensitic transformations and to reverse them after. The starting point was an annealed and slowly cooled state, the end point a sample thermally cycled 1500 times. Positron annihilation lifetime spectra and Coincidence Doppler Broadening profiles were obtained in various states and at various tem- peratures. It was found that the initial state was low in defects with positron lifetimes close to that of bulk NiTi. Cycling lead to a continuous build-up of a defect structure up to 20 0 −50 0 cycles after which saturation was reached. Two types of defects created during cycling were identified, namely pure dislo- cations and vacancies attached to dislocations.
KW - Shape memory alloy
KW - Thermal Cycling
KW - Defects
KW - Positron annihilation spectroscopy
KW - Austenite-to-martensite phase transformation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533641
DO - https://doi.org/10.1016/j.actamat.2021.117298
VL - 220
SP - 117298
PB - Elsevier Ltd.
AN - OPUS4-53364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valderrey, Virginia
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Thiourea- and Amino-Substituted Benzoxadiazole Dyes with Large Stokes Shifts as Red-Emitting Probe Monomers for Imprinted Polymer Layers Targeting Carboxylate-Containing Antibiotics
N2 - Bifunctional fluorescent molecular oxoanion probes based on the benzoxadiazole (BD) chromophore are described which integrate a thiourea binding motif and a polymerizable 2-aminoethyl methacrylate unit in the 4,7-positions of the BD core. Concerted charge transfer in this electron donor-acceptor-donor architecture endows the dyes with strongly Stokes shifted (up to >250 nm) absorption and fluorescence. Binding of electron-rich carboxylate guests at the thiourea receptor leads to further analyte-induced red-shifts of the emission, shifting the fluorescence maximum of the complexes to ≥700 nm. Association constants for acetate are ranging from 1–5×105 M−1 in acetonitrile. Integration of one of the fluorescent probes through its polymerizable moiety into molecularly imprinted polymers (MIPs) grafted from the surface of submicron silica cores yielded fluorescent MIP-coated particle probes for the selective detection of antibiotics containing aliphatic carboxylate groups such as enoxacin (ENOX) at micromolar concentrations in highly polar solvents like acetonitrile.
KW - Molecular imprinting
KW - Anion recognition
KW - Antibiotics
KW - Benzoxadiazole dyes
KW - Charge transfer
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545027
DO - https://doi.org/10.1002/chem.202104525
SN - 1521-3765
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-54502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sommer, Konstantin
A1 - Agudo Jácome, Leonardo
A1 - Hesse, René
A1 - Bettge, Dirk
T1 - Revealing the nature of melt pool boundaries in additively manufactured stainless steel by nano-sized modulation
N2 - In the current study, the 3D nature of the melt pool boundaries (MPBs) in a 316 L austenitic steel additively manufactured by laser-based powder bed fusion (L-PBF) is investigated. The change of the cell growth direction and its relationship to the MPBs is investigated by transmission electron microscopy. A hitherto unreported modulated substructure with a periodicity of 21 nm is further discovered within the cell cores of the cellular substructure, which results from a partial transformation of the austenite, which is induced by a Ga+ focused ion beam. While the cell cores show the modulated substructure, cell boundaries do not. The diffraction pattern of the modulated substructure is exploited to show a thickness ≥200 nm for the MPB. At MPBs, the cell walls are suppressed, leading to continuously connecting cell cores across the MPB. This continuous MPB is described either as overlapping regions of cells of different growing directions when a new melt pool solidifies or as a narrow planar growth preceding the new melt pool.
KW - Additive manufacturing
KW - Austenitic steel 316L
KW - Melt pool boundary
KW - Microstructural characterization
KW - Transmission electron microscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547295
DO - https://doi.org/10.1002/adem.202101699
SN - 1527-2648
VL - 24
IS - 6
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Inui, H.
A1 - Kishida, K.
A1 - Li, L.
A1 - Manzoni, Anna Maria
A1 - Haas, S.
A1 - Glatzel, U.
T1 - Uniaxial mechanical properties of face‑centered cubic singleand multiphase high‑entropy alloys
N2 - Since the high entropy concept was proposed at the beginning of the millennium, the research focus of this alloy family has been wide ranging. The initial search for single-phase alloys has expanded with the aim of improving mechanical properties. This can be achieved by several strengthening mechanisms such as solid-solution hardening, hot and cold working and precipitation hardening. Both single- and multiphase high- and medium-entropy alloys can be optimized for mechanical strength via several processing routes, as is the case for conventional alloys with only one base element, such as steels or Ni-based superalloys.
KW - High entropy alloy
KW - Compositionally complex alloys
KW - Tensile properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543955
DO - https://doi.org/10.1557/s43577-022-00280-y
VL - 47
IS - 2
SP - 168
EP - 174
PB - Springer
AN - OPUS4-54395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sternbaek, L.
A1 - Kimani, Martha Wamaitha
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Janicke, B.
A1 - Alm, K.
A1 - Gjörloff-Wingren, A.
A1 - Eriksson, H.
T1 - Molecularly Imprinted Polymers Exhibit Low Cytotoxic and Inflammatory Properties in Macrophages In Vitro
N2 - Molecularly imprinted polymers (MIPs) against sialic acid (SA) have been developed as a detection tool to target cancer cells. Before proceeding to in vivo studies, a better knowledge of the overall effects of MIPs on the innate immune system is needed. The aim of this study thus was to exemplarily assess whether SA-MIPs lead to inflammatory and/or cytotoxic responses when administered to phagocytosing cells in the innate immune system. The response of monocytic/macrophage cell lines to two different reference particles, Alhydrogel and PLGA, was compared to their response to SA-MIPs. In vitro culture showed a cellular association of SA-MIPs and Alhydrogel, as analyzed by flow cytometry. The reference particle Alhydrogel induced secretion of IL-1b from the monocytic cell line THP-1, whereas almost no secretion was provoked for SA-MIPs. A reduced number of both THP-1 and RAW 264.7 cells were observed after incubation with SA-MIPs and this was not caused by cytotoxicity. Digital holographic cytometry showed that SA-MIP treatment affected cell division, with
much fewer cells dividing. Thus, the reduced number of cells after SA-MIP treatment was not linked to SA-MIPs cytotoxicity. In conclusion, SA-MIPs have a low degree of inflammatory properties, are not cytotoxic, and can be applicable for future in vivo studies.
KW - Molecularly imprinted polymers
KW - Digital holographic cytometry
KW - Cytotoxicity
KW - Proinflammatory cytokines
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552250
DO - https://doi.org/10.3390/app12126091
SN - 2076-3417
VL - 12
IS - 12
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55225
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jiang, Shan
A1 - Wang, T.
A1 - Behren, S.
A1 - Westerlind, U.
A1 - Gawlitza, Kornelia
A1 - Persson, J. L.
A1 - Rurack, Knut
T1 - Sialyl-Tn Antigen-Imprinted Dual Fluorescent Core–Shell Nanoparticles for Ratiometric Sialyl-Tn Antigen Detection and Dual-Color Labeling of Cancer Cells
N2 - Sialyl-Tn (STn or sialyl-Thomsen-nouveau) is a carbohydrate antigen expressed by more than 80% of human carcinomas. We here report a strategy for ratiometric STn detection and dual-color cancer cell labeling, particularly, by molecularly imprinted polymers (MIPs). Imprinting was based on spectroscopic studies of a urea-containing green-fluorescent monomer 1 and STn-Thr-Na (sodium salt of Neu5Acα2-6GalNAcα-O-Thr). A few-nanometer-thin green-fluorescent polymer shell, in which STn-Thr-Na was imprinted with 1, other comonomers, and a cross-linker, was synthesized from the surface of red-emissive carbon nanodot (R-CND)-doped silica nanoparticles, resulting in dual fluorescent STn-MIPs. Dual-color labeling of cancer cells was achieved since both red and green emissions were detected in two separate channels of the microscope and an improved accuracy was obtained in comparison with single-signal MIPs. The flow cytometric cell analysis showed that the binding of STn-MIPs was significantly higher (p < 0.001) than that of non-imprinted polymer (NIP) control particles within the same cell line, allowing to distinguish populations. Based on the modularity of the luminescent core–fluorescent MIP shell architecture, the concept can be transferred in a straightforward manner to other target analytes.
KW - Cancer
KW - Core−shell particles
KW - Dual-color labeling glycan
KW - Molecular imprinting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563106
DO - https://doi.org/10.1021/acsanm.2c03252
SP - 1
EP - 14
PB - ACS Publications
AN - OPUS4-56310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yesilcicek, Yasemin
A1 - Haas, S.
A1 - Suárez Ocano, Patricia
A1 - Zaiser, E.
A1 - Hesse, René
A1 - Többens, D. M.
A1 - Glatzel, U.
A1 - Manzoni, Anna Maria
T1 - Controlling Lattice Misfit and Creep Rate Through the γ' Cube Shapes in the Al10Co25Cr8Fe15Ni36Ti6 Compositionally Complex Alloy with Hf and W Additions
N2 - Trace elements play an important role in the fine-tuning of complex material properties. This study focuses on the correlation of microstructure, lattice misfit and creep properties. The compositionally complex alloy Al10Co25Cr8Fe15Ni36Ti6 (in at. %) was tuned with high melting trace elements Hf and W. The microstructure consists of a γ matrix, γ' precipitates and the Heusler phase and it is accompanied by good mechanical properties for high temperature applications. The addition of 0.5 at.% Hf to the Al10Co25Cr8Fe15Ni36Ti6 alloy resulted in more sharp-edged cubic γ′ precipitates and an increase in the Heusler phase amount. The addition of 1 at.% W led to more rounded γ′ precipitates and the dissolution of the Heusler phase. The shapes of the γ' precipitates of the alloys Al9.25Co25Cr8Fe15Ni36Ti6Hf0.25W0.5 and Al9.25Co25Cr8Fe15Ni36Ti6Hf0.5W0.25, that are the alloys of interest in this paper, create a transition from the well-rounded precipitates in the alloy with 1% W containing alloy to the sharp angular particles in the alloy with 0.5% Hf. While the lattice misfit has a direct correlation to the γ' precipitates shape, the creep rate is also related to the amount of the Heusler phase. The lattice misfit increases with decreasing corner radius of the γ' precipitates. So does the creep rate, but it also increases with the amount of Heusler phase. The microstructures were investigated by SEM and TEM, the lattice misfit was calculated from the lattice parameters obtained by synchrotron radiation measurements.
KW - High entropy alloy
KW - Lattice misfit
KW - Creep
KW - Transmission electron microscopy
KW - X-ray diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565655
DO - https://doi.org/10.1007/s44210-022-00009-1
SP - 1
EP - 9
PB - Springer
AN - OPUS4-56565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haas, S.
A1 - Manzoni, Anna Maria
A1 - Holzinger, M.
A1 - Glatzel, U.
T1 - Influence of high melting elements on microstructure, tensile strength and creep resistance of the compositionally complex alloy Al10Co25Cr8Fe15Ni36Ti6
N2 - Due to its matrix/γ′ structure, the compositionally complex alloy (CCA) Al10Co25Cr8Fe15Ni36Ti6 has excellent properties that fulfill the requirements for a high-temperature material. This base alloy is alloyed with small amounts of high melting elements to a further improvement of its properties, which results in different shapes, fractions and sizes of the two phases γ′ and Heusler after various homogenization and annealing steps. By correlating this microstructure with time independent and dependent mechanical properties, conclusions can be drawn about the effects of the individual phases. The needle-shaped Heusler-phase leads to bad mechanical behavior if its phase fraction is too high. A fraction below 3 vol% is not critical in tensile tests, but it reduces the creep resistance compared to a purely two-phase matrix/γ′-alloy. Sharp-edged cubic γ′-particles and a coarse Heusler-phase without sharp edges in case of the base alloy with 0.5 at.% hafnium lead to the best tensile and creep properties in the high temperature range. At 750 °C, the Hf-containing alloy clearly outperforms two commercially used alloys in the targeted area of application when it comes to creep resistance.
KW - High entropy alloy
KW - Creep
KW - Microstructure
PY - 2021
DO - https://doi.org/10.1016/j.matchemphys.2021.125163
SN - 0254-0584
VL - 274
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53175
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pu, Y.
A1 - Lawrence, M. J.
A1 - Celorrio, V.
A1 - Wang, Q.
A1 - Gu, M.
A1 - Sun, Z.
A1 - Agudo Jácome, Leonardo
A1 - Russell, A. E.
A1 - Huang, L.
A1 - Rodriguez, P.
T1 - Nickel confined in 2D earth-abundant oxide layers for highly efficient and durable oxygen evolution catalysts
N2 - Low cost, high-efficiency catalysts towards water splitting are urgently required to fulfil the increasing demand for energy. In this work, low-loading (<20 wt%) Ni-confined in layered metal oxide anode catalysts (birnessite and lepidocrocite titanate) have been synthesized by facile ion exchange methodology and subjected to systematic electrochemical studies. It was found that Ni-intercalated on K-rich birnessite (Ni-KMO) presents an onset overpotential (ηonset) as low as 100 mV and overpotential at 10 mA cm−2 (η10) of 206 mV in pH = 14 electrolyte. By combining electrochemical methods and X-ray absorption and emission spectroscopies (XAS and XES), we demonstrate Ni sites are the active sites for OER catalysis and that the Mn3+ sites facilitate Ni intercalation during the ion-exchange process, but display no observable contribution towards OER activity. The effect of the pH and the nature of the supporting electrolyte on the electrochemical performance was also evaluated.
KW - Confined catalyst
KW - Low-loading
KW - Layered manganese oxide
KW - Oxygen evolution reaction
KW - Transmission electron microscopy (TEM)
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515027
DO - https://doi.org/10.1039/D0TA04031B
SN - 2050-7496
SN - 2050-7488
VL - 8
IS - 26
SP - 13340
EP - 13350
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-51502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gadelmeier, C.
A1 - Haas, S.
A1 - Lienig, T.
A1 - Manzoni, Anna Maria
A1 - Feuerbacher, M.
A1 - Glatzel, U.
T1 - Temperature Dependent Solid Solution Strengthening in the High Entropy Alloy CrMnFeCoNi in Single Crystalline State
N2 - The main difference between high entropy alloys and conventional alloys is the solid solution strengthening effect, which shifts from a single element to a multi-element matrix. Little is known about the effectiveness of this effect at high temperatures. Face-centered cubic, equiatomic, and single crystalline high entropy alloy CrMnFeCoNi was pre-alloyed by arc-melting and cast as a single Crystal using the Bridgman process. Mechanical characterization by creep testing were performed at temperatures of 700, 980, 1100, and 1200°C at different loads under vacuum and compared to single-crystalline pure nickel. The results allow a direct assessment of the influence of the chemical composition without any disturbance by grain boundary sliding or diffusion. The results indicate different behaviors of single crystalline pure nickel and CrMnFeCoNi. At 700°C CrMnFeCoNi is more creep-resistant than Ni, but at 980°C both alloys show a nearly similar creep strength. Above 980°C the creep behavior is identical and the solid solution strengthening effect of the CrMnFeCoNi alloy disappears.
KW - High entropy alloys
KW - Single crystal
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514572
DO - https://doi.org/10.3390/met10111412
VL - 10
IS - 11
SP - 1412
PB - MDPI
AN - OPUS4-51457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohring, Wencke
A1 - Karafiludis, Stephanos
A1 - Manzoni, Anna Maria
A1 - Laplanche, G.
A1 - Schneider, M.
A1 - Stephan-Scherb, Christiane
T1 - High-Temperature Corrosion of High- and Medium-Entropy Alloys CrMnFeCoNi and CrCoNi Exposed to a Multi-Oxidant Atmosphere H2O–O2–SO2
N2 - AbstractThe high-temperature corrosion behaviors of the equimolar CrCoNi medium-entropy alloy and CrMnFeCoNi high-entropy alloy were studied in a gas atmosphere consisting of a volumetric mixture of 10% H2O, 2% O2, 0.5% SO2, and 87.5% Ar at 800 °C for up to 96 h. Both alloys were initially single-phase fcc with a mean grain size of ~ 50 μm and a homogeneous chemical composition. The oxide layer thickness of CrMnFeCoNi increased linearly with exposure time while it remained constant at ~ 1 μm for CrCoNi. A Cr2O3 layer and minor amounts of (Co,Ni)Cr2O4 developed on the latter while three oxide layers were detected on the former, i.e., a thin and continuous chromium rich oxide layer at the oxide/alloy interface, a dense (Mn,Cr)3O4 layer in the center and a thick and porous layer of Mn3O4 and MnSO4 at the gas/oxide interface. Additionally, a few metal sulfides were observed in the CrMnFeCoNi matrix. These results were found to be in reasonable agreement with thermodynamic calculations.
KW - high entropy alloys
KW - corrosion
KW - oxidation
KW - scanning electron microscopy
KW - sulfidation
KW - CrMnFeCoNi
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594189
DO - https://doi.org/10.1007/s44210-023-00026-8
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-59418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Manzoni, Anna Maria
A1 - Lopez-Galilea, I.
A1 - Ruttert, B.
A1 - Laplanche, G.
A1 - Agudo Jácome, Leonardo
T1 - Influence of cooling rate on the microstructure and room temperature mechanical properties in the refractory AlMo0.5NbTa0.5TiZr superalloy
N2 - Refractory chemically complex alloys with bcc-based microstructures show great potential for high-temperature applications but most of them exhibit limited room-temperature ductility, which remains a challenge. One such example is the AlMo0.5NbTa0.5TiZr alloy, mainly consisting of a nano-scaled structure with an ordered B2 matrix and a high-volume fraction of aligned cuboidal and coherently embedded A2 precipitates. This work aims to investigate how the cooling rate after hot isostatic pressing of the AlMo0.5NbTa0.5TiZr alloy affects its microstructure and its resulting hardness and fracture toughness at room temperature. A slow cooling rate of 5 °C/min leads to a coarse microstructure consisting of aligned slabs (mean A2 precipitate ≈ 25 nm) with a nanohardness of about 8 GPa. In contrast, after the fastest cooling rate (30 °C/min), the A2 precipitates become more cubic with an edge length of ≈ 16 nm, resulting in an increase in nanohardness by 10 %. The fracture toughness is roughly independent of the cooling rate and its mean value (≈ 4.2 MPa∙m1/2) resembles that of some B2 intermetallics and other A2/B2 alloys. As the lattice misfit between the A2 and B2 phases is known to play a key role in microstructure formation and evolution, its temperature dependence between 20 and 900 °C was investigated. These findings offer insights into the evolution of the microstructure and room-temperature mechanical properties of the AlMo0.5NbTa0.5TiZr alloy, which could help the development of advanced chemically complex alloys.
KW - High entropy alloy
KW - Lattice misfit
KW - Scanning electron microscopy
KW - Transmission electron microscopy
KW - X-ray diffraction
KW - Refractory alloy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572809
DO - https://doi.org/10.1016/j.jallcom.2023.169871
SN - 0925-8388
VL - 949
SP - 169871
PB - Elsevier B.V.
AN - OPUS4-57280
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Lepore, G. O.
A1 - Widom, M.
A1 - Kasatikov, S.
A1 - Manzoni, Anna Maria
T1 - How Atomic Bonding Plays the Hardness Behavior in the Al–Co–Cr–Cu–Fe–Ni High Entropy Family
N2 - A systematic study on a face‐centered cubic‐based compositionally complex alloy system Al–Co–Cr–Cu–Fe–Ni in its single‐phase state is carried out, where a mother senary compound Al₈Co₁₇Cr₁₇Cu₈Fe₁₇Ni₃₃ and five of its suballoys, obtained by removing one element at a time, are investigated and exhaustively analyzed determining the contribution of each alloying element in the solid solution. The senary and the quinaries are compared using experimental techniques including X‐ray absorption spectroscopy, X‐ray diffraction, transmission electron microscopy, and first principles hybrid Monte Carlo/molecular dynamics simulations. Chemical short‐range order and bond length distances have been determined both at the experimental and computational level. Electronic structure and local atomic distortions up to 5.2 Å have been correlated to the microhardness values. A linear regression model connecting hardness with local lattice distortions is presented.
KW - High entropy alloys
KW - EXAFS
KW - Short-range order
KW - Microhardness
KW - Alloy design
KW - Transmission electron microscopy
KW - Lattice distortion
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593333
DO - https://doi.org/https://doi.org/10.1002/smsc.202300225
SN - 2688-4046
SP - 1
EP - 12
PB - Wiley
CY - Weinheim
AN - OPUS4-59333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gonzalez-Martinez, I.
A1 - Weinel, Kristina
A1 - Feng, W.
A1 - Agudo Jácome, Leonardo
A1 - Gemming, T.
A1 - Büchner, B.
T1 - Hybrid tungsten-carbon 2D nanostructures via in-situ gasification of carbon substrates driven by ebeam irradiation of WO2.9 microparticles
N2 - Since the TEM has the capacity to observe the atomic structure of materials, in-situ TEM synthesis methods are uniquely suited to advance our fundamental understanding of the bottom-up dynamics that drive the formation of nanostructures. E-beam induced fragmentation (potentially identified as a manifestation of Coulomb explosion) and electron stimulated desorption (ESD) are phenomena that have received attention because they trigger chemical and physical reactions that can lead to the production of various nanostructures. Here we report a simple TEM protocol implemented on WO2.9 microparticles supported on thin amorphous carbon substrates. The method produces various nanostructures such as WC nanoparticles, WC supported films and others. Nevertheless, we focus on the gradual graphitization and gasification of the C substrate as it interacts with the material expelled from the WO2.9 microparticles. The progressive gasification transforms the substrate from amorphous C down to hybrid graphitic nanoribbons incorporating W nanoparticles. We think these observations open interesting possibilities for the synthesis of 2D nanomaterials in the TEM.
KW - Transmission electron microscope (TEM)
KW - in-situ synthesis
KW - Tungsten carbide
KW - Nanoribbons
KW - Coulomb explosion
PY - 2023
DO - https://doi.org/10.1088/1361-6528/acf584
SN - 0957-4484
VL - 34
IS - 49
SP - 1
EP - 15
PB - IOP Publishing
AN - OPUS4-58279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bhattacharya, Biswajit
A1 - Rurack, Knut
T1 - Ratiometric Molecularly Imprinted Particle Probes for Reliable Fluorescence Signaling of Carboxylate-Containing Molecules
N2 - In addition to sensitivity, selectivity, and portability, chemical sensing systems must generate reliable signals and offer modular configurability to address various small molecule targets, particularly in environmental applications. We present a versatile, modular strategy utilizing ratiometric molecularly imprinted particle probes based on BODIPY indicators and dyes for recognition and internal referencing. Our approach employs polystyrene core particles doped with a red fluorescent BODIPY as an internal standard, providing built-in reference for environmental influences. A molecularly imprinted polymer (MIP) recognition shell, incorporating a green-fluorescent BODIPY indicator monomer with a thiourea binding site for carboxylate containing analytes, is grafted from the core particles in the presence of the analyte as the template. The dual-fluorescent MIP probe detects fexofenadine as the model analyte with a change in green emission signal referenced against a stable red signal, achieving a detection limit of 0.13 μM and a broad dynamic range from 0.16 μM to 1.2 mM, with good discrimination against other antibiotics in acetonitrile. By selecting a versatile dye scaffold and recognition element, this approach can be extended to other carboxylate-containing analytes and/or wavelength combinations, potentially serving as a robust multiplexing platform.
KW - Core-shell particles
KW - Molecular imprinting
KW - Pharmaceutical contaminants
KW - Self-referenced measurements
KW - Fluorescence
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609385
DO - https://doi.org/10.1021/acsami.4c09990
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-60938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gadelmeier, C.
A1 - Agudo Jácome, Leonardo
A1 - Suárez Ocano, Patricia
A1 - Glatzel, U.
T1 - Effect of stacking fault energy (SFE) of single crystal, equiatomic CrCoNi and Cantor alloy on creep resistance
N2 - Compared to mechanisms like solid solution strengthening, the stacking fault energy (SFE) should be considered as a further factor that influences the material properties. The effect of SFE of alloys or individual elements on strength and resistance can vary considerably. In the high-temperature regime above 700 ◦C, there are still significant gaps in the knowledge about the effect of the SFE on the mechanical properties of single-phase alloys. The effect of SFE on creep resistance of two face-entered cubic equiatomic medium and high entropy alloys, CrCoNi and CrMnFeCoNi, respectively, is evaluated to fill parts of these gaps. Using the Bridgman solidification process, the alloys were produced as single crystals and crept under vacuum at 700 ◦C up to 1100 ◦C. This work shows a significant impact of the lower SFE of CrCoNi on the creep behavior compared to the results of previous investigations of CrMnFeCoNi. The creep resistance of the former is higher over the complete temperature range. At very high temperatures, the strengthening effect of the stacking faults is significantly present. The formation of tetragonal stacking faults and extended dislocation nodes can be identified as the reason for this effect.
KW - Medium entropy alloy
KW - MEA
KW - HEA
KW - Single crystal
KW - CrCoNi
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602620
DO - https://doi.org/10.1016/j.msea.2024.146779
SN - 0921-5093
VL - A 908
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-60262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Weinel, Kristina
A1 - Hahn, Marc Benjamin
A1 - Lubk, Axel
A1 - Feng, Wen
A1 - Martinez, Ignacio Gonzalez
A1 - Büchner, Bernd
A1 - Agudo Jácome, Leonardo
T1 - Electron-beam-induced modification of gold microparticles in an SEM
N2 - Electron-beam-induced conversion of materials in a transmission electron microscope uses the high power density of a localized electron beam of acceleration voltages above 100 kV as an energy source to transform matter at the sub-micron scale. Here, the e-beam-induced transformation of precursor microparticles employing a low-energy e-beam with an acceleration voltage of 30 kV in a scanning electron microscope is developed to increase the versatility and efficiency of the technique. Under these conditions, the technique can be classified between e-beam lithography, where the e-beam is used to mill holes in or grow some different material onto a substrate, and e-beam welding, where matter can be welded together when overcoming the melting phase. Modifying gold microparticles on an amorphous SiOx substrate reveals the dominant role of inelastic electron-matter interaction and subsequent localized heating for the observed melting and vaporization of the precursor microparticles under the electron beam. Monte-Carlo scattering simulations and thermodynamic modeling further support the findings.
KW - Scanning electron microscopy
KW - Electron-beam-induced modification
KW - Heat transfer
KW - Gold microparticles
KW - Nanoparticles synthesis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609513
UR - https://arxiv.org/html/2408.02409v1
SP - 1
EP - 9
AN - OPUS4-60951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kingsbery, P.
A1 - Manzoni, Anna Maria
A1 - Suárez Ocano, Patricia
A1 - Többens, D. M.
A1 - Stephan-Scherb, C.
T1 - High‐temperature KCl‐induced corrosion of high Cr and Ni alloys investigated by in‐situ diffraction
N2 - High‐temperature KCl‐induced corrosion in laboratory air was observed in situ utilizing X‐ray diffraction. High Cr‐containing model alloys (Fe‐13Cr, Fe‐18Cr‐12Ni, and Fe‐25Cr‐20Ni) were coated with KCl and exposed to dry air at 560°C. KCl‐free alloys were studied in the equivalent atmosphere as a reference. After exposure to KCl‐free environments, all alloys showed the formation of very thin oxide layers, indicating good corrosion resistance. In contrast, KCl‐bearing alloys showed distinct damage after exposure.
KW - Corrosion
KW - In-situ diffraction
KW - High-temperature corrosion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600831
DO - https://doi.org/10.1002/maco.202314224
SN - 0947-5117
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-60083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feng, Wen
A1 - Gemming, Thomas
A1 - Giebeler, Lars
A1 - Qu, Jiang
A1 - Weinel, Kristina
A1 - Agudo Jácome, Leonardo
A1 - Büchner, Bernd
A1 - González-Martínez, Ignacio
T1 - Influence of magnetic field on electron beam-induced Coulomb explosion of gold microparticles in transmission electron microscopy
N2 - In this work we instigated the fragmentation of Au microparticles supported on a thin amorphous carbon film by irradiating them with a gradually convergent electron beam inside the Transmission Electron Microscope. This phenomenon has been generically labeled as “electron beam-induced fragmentation” or EBIF and its physical origin remains contested. On the one hand, EBIF has been primarily characterized as a consequence of beam-induced heating. On the other, EBIF has been attributed to beam-induced charging eventually leading to Coulomb explosion. To test the feasibility of the charging framework for EBIF, we instigated the fragmentation of Au particles under two different experimental conditions. First, with the magnetic objective lens of the microscope operating at full capacity, i.e. background magnetic field B = 2 T, and with the magnetic objective lens switched off (Lorenz mode), i.e. B = 0 T. We observe that the presence or absence of the magnetic field noticeably affects the critical current density at which EBIF occurs. This strongly suggests that magnetic field effects play a crucial role in instigating EBIF on the microparticles. The dependence of the value of the critical current density on the absence or presence of an ambient magnetic field cannot be accounted for by the beam-induced heating model. Consequently, this work presents robust experimental evidence suggesting that Coulomb explosion driven by electrostatic charging is the root cause of EBIF.
KW - Electron beam-induced fragmentation
KW - Coulomb explosion
KW - X-ray diffraction
KW - Lorenz transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600247
DO - https://doi.org/10.1016/j.ultramic.2024.113978
SN - 1879-2723
VL - 262
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-60024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Prabhakara, Prathik
T1 - Ein synergistischer Ansatz zur Charakterisierung anisotroper Materialien mit Hilfe von Ultraschall und Mikrostrukturanalyse
N2 - Es wird eine Studie zur Charakterisierung eines anisotropen Stahls vorgestellt, bei der Ultraschalluntersuchungen mit Mikrostrukturanalysen verbunden werden. Das Material weist hohe Festigkeit und Korrosionsbeständigkeit auf, zugleich ist mit anisotropen Eigenschaften die mechanischen und betrieblichen Eigenschaften beeinflussen zu rechnen. Vorläufige Ergebnisse lassen vermuten, dass weitere Untersuchungen notwendig sind, um die Fähigkeiten und Grenzen des Materials genau zu bestimmen. Es wird ein systematischer Ansatz mit Array- Prüfköpfen, Time-of-Flight Diffraction (TOFD) Technik und mikrostrukturellen Untersuchungen angewendet, um die Wechselwirkung zwischen Anisotropie und Mikrostruktur des Stahls zu analysieren. Ultraschallprüfungen mit der TOFD-Technik und in Tauchtechnik liefern Einblicke in das anisotrope Verhalten des Werkstoffes, einschließlich entsprechenden Kornorientierung, Dämpfung und Schallgeschwindigkeitsvariation. Diese Messungen führen in Verbindung mit mikrostrukturellen Analysen zu einem tieferen Verständnis des Materialverhaltens. Unser Hauptziel ist es, ein Framework zu erstellen, welches die Ultraschallantwort anisotroper Materialien mit ihren mikroskopischen Struktureigenschaften verbindet. Die vorgestellte Methodik ermöglicht eine zerstörungsfreie und zügige Bewertung der Materialintegrität, was besonders bei der Anwendung von Hochleistungsmaterialien relevant ist. Durch diesen integrativen Ansatz werden verschiedener Charakterisierungsmethoden kombiniert, um ein umfassenderes Materialverständnis zu erreichen.
T2 - DGZfP-Jahrestagung 2024
CY - Osnabrück, Germany
DA - 06.05.2024
KW - Ultrasonic Testing
KW - Time-offlight Diffraction (TOFD)
KW - Microstructure Analysis
KW - Non-Destructive Testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600122
UR - https://www.ndt.net/?id=29535
AN - OPUS4-60012
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
T1 - Preliminary study to investigate the applicability of optical strain measurement technique for the detection of hot cracks in laser metal deposited layers
N2 - Laser metal deposition (LMD) as an additive manufacturing technique became increasingly important in recent years and thus the demand for component safety. This is the reason, for the need for reliable in-situ defect detection techniques. For laser beam weld seams an optical measurement technique based on an optical flow algorithm was successfully used to define the critical straining conditions that lead to hot cracking. This algorithm was adapted for bead-on-plate weld seams on LMD deposited layers of IN718 alloy while performing external strain on the specimen in an externally loaded hot cacking test facility. The resulting transversal hot cracks along the weld seam were localized via X-Ray inspection and the type of cracking confirmed by Scanning Electron Microscopy (SEM). The strain distribution was measured in the vicinity of the solidification front and correlated to the detected hot cracks. Based on the results this technique could be adopted for LMD experiments.
T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Strain measurement
KW - Optical flow
KW - Laser Metal Deposition (LMD)
KW - Critical strain
PY - 2022
AN - OPUS4-55642
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Investigating defects caused by narrow pool shapes in deep penetration welding
N2 - Laser beam welding is a widely used joining technique in many industrial applications. This is mainly due to its many unique advantages, especially compared to conventional arc welding processes. These advantages include, among others, highly concentrated energy deposition, low total heat input and a capacity to penetrate deep into the material while causing only small welding distortions.
However, at the same time, the small dimension of the laser spot, high solidification rates, and small dimensions of the weld pool itself can provoke issues regarding the assembly tolerances of the workpiece, the hot-cracking phenomena, as well as keyhole-induced bubbles escaping from the melt.
Weld pool shapes in laser beam welding are elongated at the external, free surfaces under the action of the main driving forces in the melt – such as recoil pressure and surface tension forces – while being shorter in the internal areas of the weld pool. This leads to a regular solidification sequence from the internal zones toward the free surfaces, e.g. from the bottom to the top in partial penetration welding. However, in recent studies reported in the literature and seen in the experimental and numerical investigations of BAM Bundesanstalt für Materialforschung und -prüfung in Berlin, it was found that an internal narrowing phenomenon can occur that is often accompanied by a distinct bulging of the weld bead in deeper zones.
As the internal behaviour of the melt during the process is hardly optically accessible, several numerical models and experimental techniques were established to visualise the mechanisms of the formation of the bulging and the narrowing phenomenon and to reveal the consequences on the solidification sequence, pore formation, and filler metal dilution.
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
PY - 2022
SN - 1759-0752
IS - 57
SP - 28
EP - 29
PB - Europa Science
CY - Cambridge, UK
AN - OPUS4-56995
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kempf, A.
A1 - Agudo Jácome, Leonardo
A1 - Hilgenberg, Kai
T1 - Influence of process-relevant parameters and heat treatments on the microstructure and resulting mechanical behavior of additively manufactured AlSi10Mg via Laser Powder Bed Fusion
N2 - Within the group of additive manufacturing (AM) technologies for metals, laser powder bed fusion (L-PBF) has a leading position. Nevertheless, reproducibility of part properties has not reached sufficient maturity hindering the use for industrial applications especially for safety-relevant components. This article presents the results of various experimental tests performed with the aluminium alloy AlSi10Mg identifying reasons for the high deviations in mechanical properties. Herein, it is discussed how microstructure is influenced by different process parameters (laser power, scanning speed, energy density, building height) and how it can be adjusted by suitable post process heat treatments. The impact of resulting changes in microstructure is shown by monotonic tensile and cyclic fatigue tests considering specimens manufactured with different L-PBF machines.
T2 - LiM 2021
CY - Online meeting
DA - 21.06.2021
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - AlSi10Mg
PY - 2021
SP - 1
EP - 9
AN - OPUS4-52991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kempf, A.
T1 - Influence of process-relevant parameters and heat treatments on the microstructure and resulting mechanical behavior of additively manufactured AlSi10Mg via Laser Powder Bed Fusion
N2 - Within the group of additive manufacturing (AM) technologies for metals, laser powder bed fusion (L-PBF) has a leading position. Nevertheless, reproducibility of part properties has not reached sufficient maturity hindering the use for industrial applications especially for safety-relevant components. This article presents the results of various experimental tests performed with the aluminium alloy AlSi10Mg identifying reasons for the high deviations in mechanical properties. Herein, it is discussed how microstructure is influenced by different process parameters (laser power, scanning speed, energy density, building height) and how it can be adjusted by suitable post process heat treatments. The impact of resulting changes in microstructure is shown by monotonic tensile and cyclic fatigue tests considering specimens manufactured with different L-PBF machines.
T2 - LiM 2021
CY - Online meeting
DA - 21.06.2021
KW - Additive manufacturing
KW - AlSi10Mg
KW - Laser powder bed fusion
PY - 2021
AN - OPUS4-53046
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nicolai, Marcel
A1 - Bulling, Jannis
A1 - Narayanan, M.M.
A1 - Zeipert, Henning
A1 - Prager, Jens
A1 - Henning, Bernd
T1 - Dynamic interface behavior in coupled plates: Investigating Lamb wave mode repulsion with a spring-based model
N2 - This study investigates the phenomenon of mode repulsion in Lamb waves propagating through two coupled plates with an elastic interface. Using a spring-based coupling model and the Scaled Boundary Finite Element Method, the dispersion curves of the coupled system are analyzed under various interface conditions—weak coupling, sliding boundary, and perfect coupling. This research highlights how the mechanical stiffness of the interface influences the separation of modes and the emergence of repulsion regions. A novel focus on interface displacements reveals a unique dynamic behavior within the repulsion regions, driven by in-phase and out-of-phase oscillations of the coupled plates. The findings provide a physically grounded explanation of mode repulsion, linking it to the strain patterns in the interface. This insight lays the theoretical groundwork for future applications in material characterization and non-destructive evaluation, enabling more precise selection of Lamb wave modes for scientific and industrial purposes.
KW - Lamb waves
KW - Mode repulsion
KW - Coupled plates
KW - Elastic interface
KW - Dispersion curves
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642245
DO - https://doi.org/10.1016/j.ultras.2025.107799
SN - 0041-624X
VL - 158
SP - 1
EP - 9
PB - Elsevier BV
AN - OPUS4-64224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
T1 - Investigating Lamb wave mode repulsion with a spring-based model
N2 - Lamb waves are widely utilized in material characterization, non-destructive testing (NDT), and structural health monitoring (SHM). A unique feature of Lamb waves is mode repulsion, where dispersion curves approach each other but do not cross. This phenomenon is observed in both single and multilayer plates and is influenced by wave coupling. While mode repulsion in single plates has been linked to symmetry-breaking effects, its underlying mechanism in multilayer systems remains unclear. This study investigates mode repulsion in a coupled aluminum-polycarbonate plate system using a spring-based interface model. Dispersion curves are computed via the Scaled Boundary Finite Element Method, and time-domain simulations are used to analyze the interface dynamics. Results indicate that repulsion depends on interface stiffness, distinguishing between opening and closing repulsion regions. The study further reveals that mode repulsion corresponds to distinct oscillatory behaviors in the interface, where certain wave modes induce increased coupling spring elongation, leading to localized strain. A coupled harmonic oscillator model effectively explains opening repulsion regions but does not fully capture closing regions. Findings suggest that mode repulsion could be leveraged for non-destructive evaluation of adhesive interfaces, offering insights into bond strength characterization. This research contributes to a deeper understanding of wave interactions in multilayer structures and provides a theoretical foundation for advancing NDT and SHM techniques.
T2 - ICU2025 - International Congress on Ultrasonics 2025
CY - Paderborn, Germany
DA - 21.09.2025
KW - Lamb waves
KW - Mode repulsion
KW - Coupled plates
KW - Dispersion curves
KW - Elastic Interfaces
PY - 2025
AN - OPUS4-64225
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eggert, Lara
T1 - Korrosionsuntersuchungen im maritimen Bereich
N2 - Im Rahmen des Projektes H2Mare wurden verschiedene küstennahe sowie offshore Standorte beprobt, um die tatsächliche Korrosivität der Atmosphären zu bestimmen. Mit Offshore Auslagerungsversuchen auf einer Technikplattform (freibewitterter und überdachter Bereich) und an Windenergieanlagen (Außen- und Innenbereich), sollten Daten zur Korrosivität ermittelt werden. Diese stellen eine Grundlage für die dauerhafte und gleichzeitige wirtschaftliche Auslegung des Korrosionsschutzes für Offshore-Prozessanlagen dar. Neben den Korrosivitätsinformationen liefern die Auslagerungsversuche auch Informationen über die Performance typischer Konstruktionsmaterialien im Offshore Bereich, wie etwa nichtrostender Stähle sowie ausgewählter Korrosionsschutzmaßnahmen. Der Beitrag stellt ausgewählte Ergebnisse der Auslagerungskampagnen vor.
T2 - H2Mare-Abschlusskonferenz
CY - Rostock, Germany
DA - 23.09.2025
KW - Atmosphärische Korrosion
KW - Spaltkorrosion bei nichtrostenden Stählen
KW - Reparaturbeschichtungen
PY - 2025
AN - OPUS4-64236
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eggert, Lara
T1 - Offshore-Reparaturbeschichtungen mit Chloridvorbelastung
N2 - Bei maritimen Reparaturbeschichtungen ist eine chloridfreie Oberfläche nicht immer zu gewährleisten. Zur Untersuchung des Einflusses chloridhaltiger Verunreinigungen auf die Schutzwirkung maritimer Epoxid-Reparaturbeschichtungen wurden gestrahlte Stahlproben (Sa 2½) mit künstlichem Meerwasser besprüht. So entstanden drei Verunreinigungszustände: sauber (C0), leicht verunreinigt (C1) und stark verunreinigt (C2). Zwei Beschichtungen (A1 und A2) wurden appliziert und durch Ritzen und Impact-Schäden zusätzlich beansprucht.
T2 - H2Mare-Abschlusskonferenz
CY - Rostock, Germany
DA - 23.09.2025
KW - Reperaturbeschichtung
KW - Maritime Korrosion
KW - Wechselzyklustest
PY - 2025
AN - OPUS4-64235
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Przyklenk, A.
A1 - Balsamo, A.
A1 - O'Connor, D.
A1 - Evans, Alexander
A1 - Yandayan, T.
A1 - Akgöz, S.
A1 - Flys, O.
A1 - Zeleny, V.
A1 - Czułek, D.
A1 - Meli, F.
A1 - Ragusa, C.
A1 - Bosse, H.
T1 - New European Metrology Network for advanced manufacturing
N2 - Advanced manufacturing has been identified as one of the key enabling technologies with applications in multiple industries. The growing importance of advanced manufacturing is reflected by an increased number of publications on this topic in recent years. Advanced manufacturing requires new and enhanced metrology methods to assure the quality of manufacturing processes and the resulting products. However, a high-level coordination of the metrology community is currently absent in this field and consequently this limits the impact of metrology developments on advanced manufacturing. In this article we introduce the new European Metrology Network (EMN) for Advanced Manufacturing within EURAMET, the European Association of National Metrology Institutes (NMIs). The EMN is intended to be operated sustainably by NMIs and Designated Institutes in close cooperation with Stakeholders interested in advanced manufacturing. The objectives of the EMN are to set up a permanent stakeholder dialogue, to develop a Strategic Research Agenda for the metrology input required for advanced manufacturing technologies, to create and maintain a knowledge sharing programme and to implement a web-based service desk for stakeholders. The EMN development is supported by a Joint Network Project within the European Metrology Programme for Innovation and Research.
KW - Stakeholder
KW - Advanced manufacturing
KW - Metrology
KW - European Metrology Networks (EMNs)
KW - Strategic Research Agenda (SRA),
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530618
DO - https://doi.org/10.1088/1361-6501/ac0d25
VL - 32
IS - 11
SP - 111001
PB - IOP Publishing
AN - OPUS4-53061
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Scheuschner, Nils
A1 - Hilgenberg, Kai
T1 - In situ heat accumulation by geometrical features obstructing heat flux and by reduced inter layer times in laser powder bed fusion of AISI 316L stainless steel
N2 - Material qualification for laser powder bed fusion (L-PBF) processes are often based on results derived from additively manufactured (AM) bulk material or small density cubes, although it is well known that the part geometry has a tremendous influence on the heat flux and, therefore, on the thermal history of an AM component. This study shows experimentally the effect of simple geometrical obstructions to the heat flux on cooling behavior and solidification conditions of 316L stainless steel processed by L-PBF. Additionally, it respects two distinct inter layer times (ILT) as well as the build height of the parts. The cooling behavior of the parts is in-situ traced by infrared (IR) thermography during the built-up. The IR signals reveal significant differences in cooling conditions, which are correlated to differences in melt pool geometries. The acquired data and results can be used for validation of computational models and improvements of quality assurance.
KW - Selective laser beam melting
KW - Thermography
KW - Melt pool depth
KW - Inter layer time
KW - Ppreheating temperature
KW - Additive Manufacturing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512549
DO - https://doi.org/10.1016/j.procir.2020.09.030
VL - 94
SP - 155
EP - 160
PB - Elsevier B.V.
AN - OPUS4-51254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Azimzada, Agil
A1 - Meermann, Björn
T1 - AF4/ICP-ToF-MS for the investigation of species-specific adsorption of organometallic contaminants on natural colloidal particles
N2 - Organotin (OT) compounds, while crucial in many industrial applications, pose substantial risks to the environment and human health. The toxicity and environmental behaviour of OTs depend on their chemical form, i.e., the type and number of organic substituents. Each species thus exhibits distinct toxicity profiles and varying binding affinities to environmental colloids, which influence their mobility, bioavailability, and environmental impacts. To date, however, most studies addressed speciation and colloidal characterization separately, leaving the combined determinations of organometallics along with their carrier colloids largely elusive. Here, we develop and validate an on-line measurement system to quantify the adsorption dynamics of 10 OT species on natural colloidal particles (<500 nm). The approach integrates a versatile fractionation technique (AF4), with a state-of-the-art multi-element analyzer (ICP-ToF-MS), achieving Sn detection limits as low as 6.0 ng/L. The method separates colloid-free OT species from those bound to colloids and enables the determination of OT interactions with distinct colloidal fractions. Validated in both fractionation and detection, the method provides reliable data that could elucidate the species-specific and temporal aspects of species-colloids adsorption processes. The results feature comparative studies of 10 OT species, offering critical insights into OT mobility and distribution in environmental systems.
KW - Fractionation
KW - Speciation
KW - Adsorption
KW - Colloids
KW - Organotin
KW - AF4
KW - Nanoparticle characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625244
DO - https://doi.org/10.1016/j.jhazmat.2025.137320
SN - 1873-3336
VL - 488
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-62524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Ultrasonic assisted milling of a CoCrFeNi medium entropy alloy
N2 - Medium and High Entropy Alloys (MEA/HEA) are recently developed material classes, providing manifold applications, e.g., due to extraordinary structural properties. In that connection, the machinability as important issue for the processing of these materials was not in the scientific focus. This study focusses on experimental analysis of milling process conditions including ultrasonic assisted milling (USAM) and their effects on the resulting surface integrity of equiatomic CoCrFeNi-MEA specimens. For that reason, milling parameters (cutting speed, feed per cutting edge) were systematically varied for both conventional milling and USAM. The surface integrity was analyzed in terms of topography, defects, and residual stresses. Especially USAM leads to a decrease of occurring cutting forces and, hence, to an improvement of the surface integrity. Beneficial effects were observed in terms of lower tensile residual stresses at high cutting speed and feed per cutting edge.
T2 - 6th CIRP Conference on Surface Integrity 2022, Lyon, 06
CY - Lyon, France
DA - 08.06.2022
KW - Medium entropy alloy
KW - Ultrasonic assisted machining
PY - 2022
AN - OPUS4-55443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
A1 - Knobloch, Tim
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Concepts for bridging voids in metal additive manufacturing for repair of gas turbine blades using laser powder bed fusion
N2 - One of the main advantages of additive manufacturing (AM) processes such as laser powder bed fusion (PBF-LB/M) is the possibility to manufacture complex near-net-shape components. Therefore, the PBF-LB/M process is becoming increasingly important for the manufacturing and repair of gas turbine blades. Despite the great freedom in design, there are also limitations to the process. Manufacturing overhangs or bridging voids are some of the main challenges. In the conventional PBF-LB/M process, overhangs with angles up to 45° can be manufactured. However, gas turbine blades feature voids for cooling, which have to be bridged when using PBF-LB/M. In this work, different concepts for bridging voids are developed for future application in gas turbine blade repair. For this purpose, a test geometry is derived from the tip area of a gas turbine blade as a reference. By changing the initial geometry of the reference body, different designs for bridging voids are developed based on the PBF-LB/M requirements. Subsequently, these distinct designs are manufactured by PBF-LB/M. The different approaches are compared with respect to their volume increase. In addition, the specimens are visually inspected for warpage, shrinkage and imperfections by overheating. Out of the seven concepts developed, three concepts can be recommended for gas turbine blade repair based on low volume increase, distortion and shrinkage.
T2 - Metal Additive Manufacturing Conference - MAMC 2022
CY - Graz, Austria
DA - 26.09.2022
KW - Repair of gas turbine blades
KW - Laser Powder Bed Fusion (PBF-LB/M)
KW - Selective Laser Melting (SLM)
KW - Design for Additive Manufacturing (DfAM)
KW - Bridging voids
KW - Supportless
PY - 2022
SP - 19
EP - 28
PB - TU Graz
CY - Graz
AN - OPUS4-55868
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
A1 - Poka, Konstantin
A1 - Nilsson, R.
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - On the challenges of hybrid repair of gas turbine blades using laser powder bed fusion
N2 - Additive manufacturing (AM) processes such as laser powder bed fusion (PBF-LB/M) are rapidly gaining popularity in repair applications. Gas turbine components benefit from the hybrid repair process as only damaged areas are removed using conventional machining and rebuilt using an AM process. However, hybrid repair is associated with several challenges such as component fixation and precise geometry detection. This article introduces a novel fixturing system, including a sealing concept to prevent powder sag during the repair process. Furthermore, a high-resolution camera within an industrial PBF-LB/M machine is installed and used for object detection and laser recognition. Herein, process related inaccuracies such as PBF-LB/M laser drift is considered by detection of reference objects. This development is demonstrated by the repair of a representative gas turbine blade. The final offset between AM build-up and component is analysed. An approximate accuracy of 160 μm is achieved with the current setup.
T2 - LiM 2023
CY - Munich, Germany
DA - 26.06.2023
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Hybrid repair
KW - Position detection
KW - High-resolution camera
PY - 2023
SP - 1
EP - 9
AN - OPUS4-57836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reuter, T.
T1 - Measurement-based Detector Characteristics for Digital Twins in aRTist 2
N2 - Various software products for the simulation of industrial X-ray radiography have been developed in recent years (e.g., aRTist 2, CIVA CT, Scorpius XLab, SimCT, Wilcore) and their application potential has been shown in numerous works. However, full systematic approaches to characterise a specific CT system for these simulation software products to obtain a truthful digital twin are still missing. In this contribution, we want to present two approaches to obtain realistic grey values in X-ray projections in aRTist 2 simulations based on measured projections. In aRTist 2, the displayed grey value of a pixel is based on the energy density incident on that pixel.
The energy density is calculated based on the X-ray tube spectrum, the attenuation between source and detector as well as an energy-dependent sensitivity curve of the detector. The first approach presented in this contribution uses the sensitivity curve as a free modelling parameter. We measured the signal response at different thicknesses of Al EN-AW6082 at different tube voltages (i.e., different tube spectra). We then regarded the grey values displayed by these projections as a data regression respectively an optimisation problem and obtained the sensitivity curve that is best able to reproduce the measured behaviour in aRTist 2. The resulting sensitivity curve does not necessarily hold physical meaning but is able to simulate the real system behaviour in the simulation software.
The second approach presented in this contribution is to estimate the sensitivity curve based on assumptions about the characteristics of the scintillation detector (e.g., scintillator material, scintillator thickness and signal processing characteristics). For this approach, a linear response function (linear relationship between the deposited energy per pixel and the resulting grey value) is assumed. If the detector characteristics, which affect the simulated deposited energy, are properly modelled, the slope and offset of the response function to match the measured grey values should be the same for different tube spectra. As the offset is constant and given by the grey values measured at no incident radiation, the slope is the remaining parameter to evaluate the success of the detector modelling. We therefore adapted the detector characteristics by changing the detector setup until the slope was nearly the same for all measured tube spectra. We are aware that the resulting parameters of the scintillator material and thickness might not be the real ones, but with those modelling parameters we are able to simulate realistic grey values in aRTist 2. Both of those approaches could potentially be a step forward to a full systematic approach for a digital twin of a real CT system in aRTist 2.
T2 - 20th World Conference on Non-Destructive Testing (WCNDT 2024)
CY - Incheon, South Korea
DA - 27.05.2024
KW - Computed Tomography
KW - Digital Twin
KW - Simulation
PY - 2024
AN - OPUS4-61776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Orth, Anthony
T1 - Sensitivitätstest für ausgewählte X-Ray CT Prüfkörper
N2 - Industrial X-Ray computed tomography (XCT) is an alternative procedure to tactile coordinate measuring machines (CMM) for dimensional measurement as it has the advantage to be able to measure internal and external features. However, the uncertainty determination according to the standard VDI/VDE 2630 Part 2.1 is both complex and resource consuming. The procedure could be simplified with the help of computer simulations if a suitable digital replica of the XCT machine is available.
The project CTSimU2 has the aim of establishing a guideline for evaluating the applicability of such a digital replica. In this context, the work presented here focuses on: determining the sensitivity of two specimens, on several modelling parameters; determining the significance of the modelled parameters; and estimating the sensitivity of the specimens measurands. The approach was to determine the effects of selected parameters and parameter interactions on dimensional measurands of the specimens by simulation. These effects were determined by varying the parameters in accordance with a D-optimal experimental design, with 83 runs for 10 parameters. The measurands were distances, flatness of fitted planes, cylindricities of fitted cylinders, and testing of modular transfer function on edges. By definition the effects are linked to the coefficients of the statistical model – multiple linear regression – related to the design criterion.
The results yielded good models with high regression coefficients. The models for distances were dominated by the geometrical parameters, whereas parallelism and flatness responded more to x-ray parameters. The results have shown that both specimens are necessary to test the digital replica.
T2 - DGZfP Jahrestagung 2024
CY - Osnabrück, Germany
DA - 06.05.2024
KW - X-ray CT
KW - Dimensional Measurements
KW - Simulation
KW - Specimen Sensitivity
KW - DoE
PY - 2024
AN - OPUS4-61797
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kasperl, S.
T1 - Realistic simulation of real X-ray computed tomography systems with basic-qualified simulation software - the CTSimU2 project
N2 - Industrial X-ray computed tomography (CT) completely captures workpieces, including their inner and outer structures for metrology purposes. However, previous effort to determine task-specific measurement uncertainty is not always justifiable. Simulating the measuring process allows to estimate measurement uncertainty numerically and to predict systematic measurement deviations. For any future simulation applications it is essential that the simulation is reliable. The WIPANO research project CTSimU2 – “Realistic Simulation of Realistic X-Ray Computed Tomography Systems with basic-qualified simulation software” aims to develop tools for realistic replication of industrial CT systems in a simulation software. As a precondition, simulation software systems must be basic-qualified by the test framework developed in the previous project CTSimU1. The test framework tests sufficient physical correctness and functionality of the software. For a realistic simulation, not only the quality of the software, but in particular the quality of the real CT system’s parameterization within the simulation software is crucial. Four steps yield the desired parametrization: First, acquire data on the real CT system (step 1), evaluate data to generate general parameter specifications (step 2), transfer parameters into the specific simulation software (step 3), and validate parameters with a suitable test (step 4). In addition to developing a toolbox with general methods for data acquisition and data evaluation, this project therefore aims to develop a test, on the basis of which the sufficiently correct simulation of a real system can be evaluated. As in the preliminary project CTSimU1, the results obtained are to be transferred into a draft guideline for the VDI/VDE 2630 series of guidelines. This article presents an overview of the project and the initial results. Acknowledgments: This work was funded through the project Wipano-CTSimU2 (WIPANO project 03TN0049A-L). WIPANO projects are financed by the German Federal Ministry for Economic Affairs and Climate Action and managed by Project Management Jülich.
T2 - 20th World Conference on Non-Destructive Testing (WCNDT 2024)
CY - Incheon, South Korea
DA - 27.05.2024
KW - Computed Tomography
KW - Simulation
KW - Digital Twin
PY - 2024
AN - OPUS4-61795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grimmer, Christoph
T1 - Constant emitting reference material for material test procedures
N2 - In industrialised countries more than 80% of the time is spent indoors. Products, such as building materials and furniture, emit volatile organic compounds (VOCs), which are therefore ubiquitous in indoor air. VOC in combination may, under certain environmental and occupational conditions, result in reported sensory irritation and health complaints. Emission concentrations can become further elevated in new or refurbished buildings where the rate of air exchange with fresh ambient air may be limited due to improved energy saving aspects. A healthy indoor environment can be achieved by controlling the sources and by eliminating or limiting the release of harmful substances into the air. One way is to use (building) materials proved to be low emitting. Meanwhile, a worldwide network of professional commercial and non-commercial laboratories performing emission tests for the evaluation of products for interior use has been established. Therefore, comparability of test results must be ensured. A laboratory’s proficiency can be proven by internal and external validation measures that both include the application of suitable emission reference materials (ERM). For the emission test chamber procedure according to EN 16516, no artificial ERM is commercially available. The EU-funded EMPIR project MetrIAQ aims to fill this gap by developing new and improved ERMs. The goal is to obtain a material with a reproducible and temporally constant compound release (less than 10% variability over 14 days). Different approaches, such as the impregnation of porous materials, are being tested. The generation as well as results of the most promising materials will be presented.
T2 - Airmon 2022
CY - Bristol, UK
DA - 07.11.2022
KW - Emission reference materials
KW - Emission test chamber procedure
KW - Quality assurance
KW - Reference material
PY - 2022
AN - OPUS4-56575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heller, C.
A1 - Altmann, Korinna
A1 - Braun, U.
A1 - Kerndorff, A.
A1 - Bannick, C.-G.
A1 - Fuchs, M.
A1 - Thamsen, P. U.
T1 - Garment ageing in a laundry care process under household‐like conditions
N2 - This study reflects typical consumer textile washing behaviour while taking into account existing standards in the household appliance and garment industries. Two garments were washed repeatedly with artificial dirt and detergent 30 times. The collected washing water was separated using fractional filtration. Textile physical tests were used to follow property changes of the garments, the microplastic release is determined using thermoextraction/desorbtion–gas chromatography/mass spectrometry and the total organic carbon was measured as a sum parameter for the organic bonded carbon. This article shows the importance of a reality‐based approach when investigating microplastics of textile origin in the laundry care process. Deposits of detergent and dirt on the textiles were detected. The total mass of sieve residues was much higher than the release of synthetic polymers. The cotton content of the garments causes a much higher fibre release than synthetic fibres. Both will lead to false results by purely gravimetric analysis because nonpolymer fibres will be included microplastic mass. The results cannot be generalised only by the main polymer type, knowledge of the textile construction must be included for final evaluation.
KW - Fibre release
KW - Microplastics
KW - TED-GC/MS
KW - Washing machine
PY - 2023
DO - https://doi.org/10.1002/appl.202200086
SP - 1
EP - 8
PB - Wiley online library
AN - OPUS4-56976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Needs, concepts and state of the art: Top-down production of reference materials for micro- and nanoplastics and their use in harmonisation processes
N2 - The talk explains the top-down production of materials suitable for mircoplastics and nanoplastics and the use in ILCs.
T2 - EUROLAB webinar: MICROPLASTICS: regulations, standards and the role of laboratories
CY - Online meeting
DA - 15.02.2023
KW - Microplastics
KW - Nanoplastics
KW - ILC
KW - Milling
PY - 2023
AN - OPUS4-57008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - PlasticsEurope - plastic powders - Reference materials
N2 - The talk gives ideas about possible collaboration between BAM and PlasticEurope and their BRIGID project.
T2 - Project meeting of BRIDGIT project of PlasticsEurope
CY - Online meeting
DA - 01.02.2023
KW - Microplastics
KW - PlasticEurope
PY - 2023
AN - OPUS4-57012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Stakeholder Workshop – Plastictrace WP1
N2 - The talk is about WP1 in the PlasticTrace project funded by Euromat. The projects harmonizes microplastic analysis by developing SOPs and reference materials. WP1 is responsible for material selection and preparation. All particles are homogeneity and stability checked according to ISO guide 35.
T2 - Stakeholder workshop of PlasticTrace project
CY - Online meeting
DA - 14.12.2022
KW - Microplastic
KW - Microplastics standardisation
KW - Reference materials
PY - 2022
AN - OPUS4-56772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strzelczyk, Rebecca
T1 - Zeolites loaded with VOCs as reference for material emissions testing
N2 - Nowadays, people spend most of their time indoors. Thus, a good indoor air quality is important. Emissions of volatile organic compounds (VOCs) from furniture and building materials can cause health complaints1. Quantitative VOC-emission testing is carried out under standardized conditions in emission test chambers. In the presented project an emission reference material (ERM) is developed that emits a defined mixture of VOCs which is required for quality assurance and -control (QA/QC) measures. Porous materials (e.g zeolites, activated carbons, MOFs or aerogels) are used as reservoir materials and impregnated with VOC. The porous materials are selected, among others, by their pore size, pore size distribution, polarity and availability. Due to their regular pore structure zeolites are tested at first. For a prediction of the emission profile, the ERM is supposed to exhibit a constant emission rate over time. The aim is a stability of ≤ 10 % change in the emission rate over a minimum of 14 days.
Method
For impregnation, the material is placed into an autoclave inside a rotatable basket. The VOC is added and the autoclave is closed. Afterwards, CO2 is inserted. The closed system is then heated to the supercritical point of CO2 (31 °C, 73.75 bar). In this state, the CO2 acts as solvent for the VOC. By rotating the basket, the distribution of the VOC is ensured. After a few minutes, the pressure is decreased slowly and the CO2 is released. For the determination of the emission profile, the impregnated sample is placed into an emission test chamber. These chambers can be operated either with dry or humid air (50 ± 5 % rel. humidity). Every second to third day, air samples are taken and analyzed by gas chromatography. For an ideal impregnation, several different pressures and temperatures as well as impregnation times are tested.
Results
Two zeolite materials tested in dry air conditions reach emission profiles with a decrease of less than 10 % over 14 days (heptane and toluene, respectively). Further it was discovered that smaller pellets of the same zeolite show better results than bigger particles. When the pore size of a zeolite is too small, e.g. 0.3 nm, the VOC cannot be absorbed sufficiently. The main disadvantage of zeolites is their hygroscopicity because it has a large impact on the release of VOC when they are used in emission test chambers under standardized test conditions (23 °C, 50 % rel. humidity). Activated carbons have emission profiles with a larger change over 14 days. However, the high hydrophobicity allows measurements in humid air conditions which was not possible with the before mentioned hygroscopic zeolites. It is possible to impregnate powdered materials as well, and thus powdered non-hygroscopic (n.h.) zeolites were impregnated. Their emission profiles are comparable to those of the activated carbons. The use of methylated hygroscopic zeolites with a decrease in hygroscopicity did not yield successful emission measurements. The change over 14 days is calculated only for the stable phase (~250–300 h).
The desired stability of ≤ 10 % change of the emission rate over 14 days could already be reached under dry testing conditions. Further investigations under humid conditions show that zeolites with high Si/Al-ratios are non-hygroscopic and comparable to activated carbons (20–30 % change). The next step is to reduce the change in the emission rate of these materials to the aimed ≤ 10 % over 14 days.
T2 - Deutsche Zeolithtagung
CY - Jena, Germany
DA - 28.02.2024
KW - VOC
KW - Emission
KW - Quality assurance
KW - Reference material
KW - Zeolite
PY - 2024
AN - OPUS4-59843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strzelczyk, Rebecca
T1 - Constant emitting reference material for emissions test procedures
N2 - Since nowadays people spend most of their time indoors, a healthy environment is essential. Volatile organic compounds (VOCs) emitted from furniture and building materials are reported to cause health complaints. Therefore, the usage of low emitting materials will improve the indoor air quality. Quantitative VOC emission testing is usually conducted in emission test chambers under specified controlled conditions as described in DIN 16000-9 and DIN EN 16516.
For reasons of quality control/quality assurance (QC/QA) and for a better comparability of test results from different laboratories, suitable emission reference materials (ERM) are needed. Here, it is important to have a homogenous material with known emission rates over a specific time. Different approaches can be found in literature, inter alia polymer films loaded with the target compound to be released again, or a lacquer material to which a VOC mixture is added. After curing of the lacquer, the material can be loaded into a test chamber. Drawback of those approaches are their relatively fast decreasing emission profiles. For QC/QA purposes according to the test standards, VOC sources with constant emission profiles are desirable.
The EU-funded research project MetrIAQ “Metrology for the determination of emissions of dangerous substances from building materials into indoor air” is working on a multi-component ERM with an envisaged instability of ≤ 10 % in the emission rate over at least 14 days.
Within a doctoral thesis porous materials are impregnated with VOCs. Supercritical CO2 is used as solvent. Thus, the impregnated material does not contain any solvent that may show a measurable amount of emission in the emission test chamber. Furthermore, CO2 has the benefits to have a good availability and low costs. For the selection of porous materials several properties like the pore size, the surface, and the interaction with the components in the atmosphere need to be considered. The impregnation method is optimised while the different porous materials are tested. For the selection of porous materials the pores need to be large enough for the VOC molecules, further influence of the pore size is tested.
T2 - Healthy Buildings
CY - Aachen, Germany
DA - 11.06.2023
KW - VOC
KW - Emission
KW - Quality assurance
KW - Reference material
PY - 2023
AN - OPUS4-59842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
T1 - On the challenges of hybrid repair of gas turbine blades using laser powder bed fusion
N2 - Additive manufacturing (AM) processes such as laser powder bed fusion (PBF-LB/M) are rapidly gaining popularity in repair applications. Gas turbine components benefit from the hybrid repair process as only damaged areas are removed using conventional machining and rebuilt using an AM process. However, hybrid repair is associated with several challenges such as component fixation and precise geometry detection. This article introduces a novel fixturing system, including a sealing concept to prevent powder sag during the repair process. Furthermore, a high-resolution camera within an industrial PBF-LB/M machine is installed and used for object detection and laser recognition. Herein, process related inaccuracies such as PBF-LB/M laser drift is considered by detection of reference objects. This development is demonstrated by the repair of a representative gas turbine blade. The final offset between AM build-up and component is analysed. An approximate accuracy of 160 μm is achieved with the current setup.
T2 - LiM 2023
CY - Munich, Germany
DA - 26.06.2023
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Hybrid repair
KW - Position detection
KW - High-resolution camera
PY - 2023
AN - OPUS4-57837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Thermal desorption spectroscopy for identification of diffusion and trapping in CoCrFeMnNi high-entropy alloy at 1,000 bar high-pressure hydrogen
N2 - First studies on the mechanical behavior of high-entropy alloys (HEAs) in high-pressure hydrogen environment are available. In contrast, the underlying hydrogen absorption, diffusion and trapping in these HEAs like the Cantor-alloy was less in the scientific scope so far. For that reason, the CoCrFeMnNi-HEA was compared to a conventional AISI 316L austenitic steel, by exposing to high-pressure hydrogen charging at 200 bar and very-high pressure at 1,000 bar. Thermal desorption analysis (TDA) was applied with different heating rates (0.125 K/s to 0.500 K/s). The underlying TDA spectra were analyzed in terms of a reasonable peak deconvolution to into a defined number of peaks and the calculation of the activation energies for the respective and predominant hydrogen trap sites. Both materials show a comparable hydrogen diffusivity. The obtained activation energies suggest that in case of the CoCrFeMnNi-HEAs an interaction of the austenitic phase as well as the direct atomic bonding of hydrogen to the metal atoms are the dominant traps, since “impurities” such as carbides or inclusions are only present in trace amounts. Available literature suggests that the Cr and Mn-content is here of special interest for the direct hydrogen bonding at solute atoms. Despite the activation energy, the trap occupancy rate must be considered in terms of a pressure-related hydrogen absorption. The derived apparent hydrogen solubility was in the order: 316L < CoCrFeMnNi-HEA for both charging pressures. Especially, the 1,000 bar values lead to noteworthy results with > 70 wt.ppm for the AISI 316L and >130 wt.ppm for the CoCrFeMnNi. In fact, both the hydrogen diffusion and trapping data on gaseous high-pressure hydrogen charged HEAs are rare so far. The results of the present study allow a deeper understanding of hydrogen trapping in the regarded CoCrFeMnNi-system.
T2 - 1st Conference on Hydrogen in Materials Science and Engineering (H2-MSE)
CY - Freiburg, Germany
DA - 11.02.2025
KW - High-entropy alloy
KW - Hydrogen diffusion
KW - High-pressure charging
KW - Thermal desorption analysis
PY - 2025
AN - OPUS4-62543
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Benjamin, Merz
T1 - Advanced camera calibration for lens distortion correction in hybrid additive manufacturing processes
N2 - Hybrid additive manufacturing is becoming increasingly important in the field of additive manufacturing. Hybrid approaches combine at least two different manufacturing processes. The focus of this work is the build-up of geometries onto conventionally manufactured parts using laser-based powder bed fusion of metals (PBF-LB/M). The hybrid build-up requires a precise position detection system inside the PBF-LB/M machines to determine the exact position of the existing component. For this purpose, high-resolution camera systems can be utilized. However, the use of a camera system is associated with several challenges. The captured images are subject to various distortions of the optical path. Due to these distortions, it is not possible to use the images for measurements and, therefore, it is not possible to calculate the positions of objects. In this study a homography matrix is calculated to correct keystone distortion in the images. Different calibration patterns have been tested for the calculation of the homography matrix. The influence of the number of calibration points on the precision of position detection of objects is determined. Furthermore, the influence of an additional camera calibration by using ChArUco boards is evaluated. The result is a camera calibration workflow with associated calibration pattern for a precise position detection of parts inside PBF-LB/M machines allowing a hybrid build-up with minimum physical offset between base component and build-up.
T2 - euspen’s 24th International Conference & Exhibition
CY - Dublin, Ireland
DA - 10.06.2024
KW - Aditive Manufacturing
KW - Hybrid build-up
KW - Position detection
KW - Camera calibration
PY - 2024
AN - OPUS4-60600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuschner, Nils
A1 - Oster, Simon
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Comparison of NIR and SWIR thermography for defect detection in Laser Powder Bed Fusion
N2 - Since laser powder bed fusion (PBF-LB/M) is prone to the formation of defects during the building process, a fundamental requirement for widespread application is to find ways to assure safety and reliability of the additively manufactured parts. A possible solution for this problem lies in the usage of in-situ thermographic monitoring for defect detection. In this contribution we investigate possibilities and limitations of the VIS/NIR wavelength range for defect detection. A VIS/NIR camera can be based on conventional silicon-based sensors which typically have much higher spatial and temporal resolution in the same price range but are more limited in the detectable temperature range than infrared sensors designed for longer wavelengths. To investigate the influence, we compared the thermographic signatures during the creation of artificially provoked defects by local parameter variations in test specimens made of a nickel alloy (UNS N07208) for two different wavelength ranges (~980 nm and ~1600 nm).
KW - Laser powder bed fusion
KW - PBF-LB/M
KW - Thermography
KW - Additive manufacturing
KW - NDT
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610380
DO - https://doi.org/10.1016/j.procir.2024.08.122
VL - 124
SP - 301
EP - 304
PB - Elsevier B.V.
AN - OPUS4-61038
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Fügetechnik in Wasserstofftechnologien: Erzeugung, Transport, Speicherung, Nutzung
N2 - Der Vortrag gibt einen kurzen Überblick über die Bedeutung der Fügetechnik in Wasserstofftechnologien und über zukünftige FuE-Bereiche. Fügetechnologien haben dabei wesentliche Bedeutung für die Umsetzung von technischen Komponenten der Wasserstofftechnologien. Forschungsschwerpunkte ergeben sich insbesondere für die Erzeugung und den Transport des Wasserstoffs.
T2 - Vortragsreihe des DVS Bezirksverbandes Berlin
CY - Berlin, Germany
DA - 22.02.2023
KW - Wasserstoff
KW - Fügetechnik
KW - Forschung
KW - Review
PY - 2023
AN - OPUS4-57040
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Local mechanical properties of TIG dissimilar metal welded high entropy alloy with austenitic steel AISI 304
N2 - High entropy alloys (HEA) are a new class of materials that have been investigated since the early 2000s and offer great potential to replace conventional alloys. However, since they sometimes have significant contents of expensive alloying elements such as Co or Ni, their use is only conceivable in highly stressed areas of components. For this purpose, the weldability with conventional alloys such as high-alloy austenitic steels must be investigated. In addition to the resulting microstructure, the mechanical properties are also fundamental for the usability of HEAs in DMWs. For this purpose, TIG welds of CoCrFeMnNi HEA (cold rolled and recrystallized state) with AISI 304 austenitic steel are investigated. These mechanical properties are analyzed in this work by means of tensile tests and local hardness measurement. The local strain behavior of the welded joints is also characterized by means of Digital Image Correlation (DIC). The results of the local hardness measurement show a clear influence of the initial condition of the HEA on the HAZ. Thus, the HEA in the cold-rolled condition shows a clear softening because of recrystallization processes in the HAZ. On the other hand, there is no influence on the hardness of the weld metal, which is approx. 200 HV0.1 in both cases. The tensile tests show a consistent failure of the weld in the weld metal. However, regardless of the HEA condition, strengths in the range of the recrystallized HEA (RM ~ 550–600 MPa) are achieved, although with significantly reduced fracture elongations.
T2 - IIW Intermediate Meeting of Commission II-A
CY - Garching, Germany
DA - 06.03.2023
KW - High-entropy alloy
KW - Welding
KW - Dissimilar metal weld (DMW) joint
KW - Mechanical properties
KW - Digital image correlation
PY - 2023
AN - OPUS4-57108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - D'Accardi, E.
T1 - Capability of active thermography to detect and localize pores in Metal Additive Manufacturing materials
N2 - A powerful tool to understand, demonstrate and explain the limits of the pulsed technique in terms of detectability and localizability of AM keyhole pores has been assessed by comparing the active thermographic approach (both experimental and FEM simulations) to Computed Tomography results;
✓ µCT results demonstrate that the intended defect geometry is not achieved; indeed a network of voids (microdefects consisting of small sharp-edged hollows with a complicated, almost fractal, inner surface) was found;
✓ both Exp-PT and FEM results explains clearly why no indication of defect related to the thermal contrasts could be found during the investigation of an uncoated surface. However, the application of further data evaluations focusing on the thermal behavior and emissivity evaluation (PPT post data processing) enable the detection of some defects;
✓ coating facilitates a closer inspection of inner defects, but inhomogeneities of the coating could impair the spatial resolution and lead to the emergence of hotspots (the FEM simulation reached its limit with this extreme geometry where a 25 µm thin disc is considered at a 1 cm thick specimen in millisecond time resolution);
✓ both Exp-PT and FEM results allow the conclusion that very short pulses of 200 ms or shorter should be sufficient to detect these defects below, but near the surface; besides a short duration of the thermal phenomenon it should be emphasized, about 0.04 s (high frame rate camera);
T2 - Convegno AIAS 2020
CY - Online meeting
DA - 02.09.2020
KW - Additive Manufacturing
KW - Laser powderbed fusion
KW - Pores
KW - Thermography
PY - 2020
AN - OPUS4-51922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - Comparison of NIR and SWIR thermography for defect detection in laser powder bed fusion
N2 - Since laser powder bed fusion (PBF-LB/M) is prone to the formation of defects during the building process, a fundamental requirement for widespread application is to find ways to assure safety and reliability of the additively manufactured parts. A possible solution for this problem lies in the usage of in-situ thermographic monitoring for defect detection. In this contribution we investigate possibilities and limitations of the VIS/NIR wavelength range for defect detection. A VIS/NIR camera can be based on conventional silicon-based sensors which typically have much higher spatial and temporal resolution in the same price range but are more limited in the detectable temperature range than infrared sensors designed for longer wavelengths. To investigate the influence, we compared the thermographic signatures during the creation of artificially provoked defects by local parameter variations in test specimens made of a nickel alloy (UNS N07208) for two different wavelength
ranges (~980 nm and ~1600 nm).
T2 - 13th CIRP Conference on Photonic Technologies - LANE 2024
CY - Fürth, Germany
DA - 15.09.2024
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Nondestructive Testing
KW - Defect Detection
KW - Thermography
PY - 2024
AN - OPUS4-61285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Korrosion und Korrosionsschutzverfahren: Teil 1 Grundlagern der Korrosion metallener Werkstoffe
N2 - Der Übersichtsvortrag vermittelt Kenntnisse zu den Grundlagen der Korrosion metallischer Werkstoffe für das KKS Grundlagenseminar für erdverlegte Anlagen und Stahlbetonbau zur Vorbereitung auf die Zertifikatsprüfung DIN EN 15257. Diese Kenntnisse bilden die Grundlage zum Verständnis der Beeinflussung von Korrosionssystemen durch die Anwendung kathodischer Schutzmaßnahme
T2 - Fachausbildung Kathodischer Korrosionsschutz - Grundlagenkurs für erdverlegte Anlagen, Stahlbeton und Innenschutz
CY - Online meeting
DA - 14.02.2024
KW - Korrosion
KW - Atmosphäre
KW - Passivität
KW - Stahl
KW - Nichtrostender Stahl
PY - 2024
AN - OPUS4-59531
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudry, Mohsin Ali
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Experimental and numerical comparison of heat accumulation during laser powder bed fusion of 316L stainless steel
N2 - Heat accumulation during laser powder bed fusion (LPBF) of metallic build parts can adversely affect their microstructure and mechanical properties. To study the heat accumulation during 316L steel based parts manufactured by LPBF, a finite element method (FEM) based numerical study is carried out. For the investigation, a computationally efficient FEM based model, where the whole layer is simultaneously exposed to a heat source, is used. The simulation results are compared with experimental results to validate the numerical model. While considering different influencing factors such as volumetric energy density (VED) and inter-layer time (ILT), the FEM model is shown to successfully simulate the process of heat accumulation during LPBF based manufacturing of a cuboidal shaped geometry. It is shown that ILT and VED have a significant effect on heat accumulation. The validated numerical model provides a good basis for the optimization of processing parameters and geometries for a future investigation of a reduction of heat accumulation effects. Furthermore, it can be used to quickly provide preheating boundary conditions for detailed investigations by different model approaches at a finer scale for future studies.
KW - Laser powder bed fusion
KW - Finite element method
KW - Heat accumulation
KW - Inter-layer time
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545115
DO - https://doi.org/10.1007/s40964-022-00282-x
SP - 1
EP - 13
PB - Springer
AN - OPUS4-54511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Griesche, Axel
T1 - Measurement of Hydrogen Distributions in Metals by Neutron Radiography and Tomography
N2 - Neutron imaging is a valuable tool for measuring hydrogen distributions qualitatively and quantitatively in metals. Time-resolved neutron radiography allows to measure hydrogen mass flow inside cm thick steel samples with ~10 s temporal resolution. Hydrogen accumulations around cracks in embrittled iron samples can be visualized three-dimensionally by neutron tomography. This quality of information allows new insights for the analysis of damage mechanisms on a micrometer scale, e.g. of hydrogen blistering. Even the gas pressure of molecular hydrogen in crack cavities has been measured from tomographic reconstructions to be in the range of 5 MPa to 15 MPa for technical iron. Further, this method is non-destructive and provides local information in situ and in all three dimensions with a spatial resolution of 20 - 30 µm. The combination with other methods gives a new quality of information, e.g. of the hydrogen allocation on fractured surfaces.
T2 - Symposium on large scale facilities
CY - Berlin, Germany
DA - 09.03.2020
KW - Hydrogen embrittlement
KW - Neutron imaging
KW - Hydrogen diffusion
KW - Neutron radiography
KW - Neutron tomography
PY - 2020
AN - OPUS4-50548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Korrosion und Korrosionsschutzverfahren: Teil 2 Korrosionsschutzverfahren
N2 - Der Vortrag thematisiert die Grundlagen des Korrosionsschutzes. Dieser kann planungs-,werkstoff oder mediumsseitig erfolgen oder mit elektrochemischen Methoden umgesetzt werden. Der Vortrag beschreit die Korrosivitäten der Atmosphären und welche Maßnahmen für den Korrosionsschutz daraus abgeleitet werden können.
T2 - Fachausbildung Kathodischer Korrosionsschutz - Grundlagenkurs für erdverlegte Anlagen, Stahlbeton und Innenschutz
CY - Online meeting
DA - 14.02.2024
KW - Korrosion
KW - Nichtrostende Stähle
KW - Passivität
KW - Korrosionsschutz
PY - 2024
AN - OPUS4-59530
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Research data infrastructures as enablers for materials design
N2 - Suitable material solutions are of key importance in designing and producing components for engineering systems – either for functional or structural applications. Materials data are generated, transferred, and introduced at each step along the complete life cycle of a component. A reliable materials data space is therefore crucial in the digital transformation and an important prerequisite for machine learning in materials science.
Therefore, the consortium NFDI MatWerk aims to develop a sustainable infrastructure for the standardized digital representation of materials science and engineering (MatWerk). The goal is to seamlessly integrate decentralized data and metadata, experimental and computational workflows, and a materials ontology to maximize interoperability and reproducibility of materials data processing. To this end, data use profiles of participant projects from different sub-disciplines are analyzed to identify the most relevant scientific scenarios within MatWerk.
Similarly, the Plattform MaterialDigital (PMD) is committed to provide a prototypical infrastructure for the digitalization of materials in an industrial context implemented by decentralized data servers, semantic data schemas and digital workflows. The standards, methods, and tools developed within the PMD are deployed and consolidated within the context of currently more than 20 BMBF-funded academic and industrial research consortia. Scientific workflow environments represent a major focus area, including efforts to improve the definition and representation of digital workflows, as well as their distribution in form of a workflow store.
In this presentation we will describe the overarching visions behind these initiatives, their status, and progress of dissemination with a focus on the workflow activities and the connection to machine learning applications. Following the philosophy of both consortia, specific examples will be used to demonstrate innovative and pragmatic solutions.
T2 - MLEdays TUHH 2023
CY - Hamburg, Germany
DA - 25.09.2023
KW - Digital Infrastructure
KW - Workflows
KW - Integrated Development Environment
PY - 2023
AN - OPUS4-58853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Residual stress formation in DED-arc manufactured high strength steel components
N2 - Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
T2 - IIW Intermediate Meeting C-XIII
CY - Online meeting
DA - 20.04.2023
KW - Additive Manufacturing
KW - High strength steel
KW - Residual Stress
PY - 2023
AN - OPUS4-59308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Diffusion and trapping of gaseous hydrogen charged CoCrFeMnNi-HEA vs. austenitic steel AISI 316L at pressure up to 1000 bar
N2 - First studies on the mechanical behavior of high-entropy alloys (HEAs) in high-pressure hydrogen environment are available. In contrast, the underlying hydrogen absorption, diffusion and trapping in these HEAs like the Cantor-alloy was less in the scientific scope so far. For that reason, the CoCrFeMnNi-HEA was compared to a conventional AISI 316L austenitic steel, by exposing to high-pressure hydrogen charging at 200 bar and very-high pressure at 1,000 bar. Thermal desorption analysis (TDA) was applied with different heating rates (0.125 K/s to 0.500 K/s). The underlying TDA spectra were analyzed in terms of a reasonable peak deconvolution to into a defined number of peaks and the calculation of the activation energies for the respective and predominant hydrogen trap sites. Both materials show a comparable hydrogen diffusivity. The obtained activation energies suggest that in case of the CoCrFeMnNi-HEAs an interaction of the austenitic phase as well as the direct atomic bonding of hydrogen to the metal atoms are the dominant traps, since “impurities” such as carbides or inclusions are only present in trace amounts. Available literature suggests that the Cr and Mn-content is here of special interest for the direct hydrogen bonding at solute atoms.
T2 - MSE 2024: International Materials Science and Engineering Congress
CY - Darmstadt, Germany
DA - 24.09.2024
KW - High-entropy alloy
KW - Hydrogen
KW - Trapping
KW - Diffusion
KW - High-pressure charging
PY - 2024
AN - OPUS4-61156
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Lei
A1 - Magdysyuk, Oxana V.
A1 - Jiang, Fuqing
A1 - Wang, Yiqiang
A1 - Evans, Alexander
A1 - Kabra, Saurabh
A1 - Cai, Biao
T1 - Mechanical performance and deformation mechanisms at cryogenic temperatures of 316L stainless steel processed by laser powder bed fusion: In situ neutron diffraction
N2 - Manufacturing austenitic stainless steels (ASSs) using additive manufacturing is of great interest for cryogenic applications. Here, the mechanical and microstructural responses of a 316L ASS built by laser powder bed fusion were revealed by performing in situ neutron diffraction tensile tests at the low-temperature range (from 373 to 10 K). The stacking fault energy almost linearly decreased from 29.2 ± 3.1 mJm⁻² at 373 K to 7.5 ± 1.7 mJm⁻² at 10 K, with a slope of 0.06 mJm⁻²K⁻¹, leading to the transition of the dominant deformation mechanism from strain-induced twinning to martensite formation. As a result, excellent combinations of strength and ductility were achieved at the low-temperature range.
KW - Condensed Matter Physics
KW - General Materials Science
KW - Mechanics of Materials
KW - Metals and Alloys
KW - Mechanical Engineering
PY - 2022
DO - https://doi.org/10.1016/j.scriptamat.2022.114806
SN - 1359-6462
VL - 218
SP - 1
EP - 7
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-59317
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Repräsentative Prüfkörper – Ein Beitrag zur Komponentensicherheit beim pulverbettbasierten Laserstrahlschmelzen (PBF-LB/M)
N2 - Die thermische Historie beim additiven Aufbau von komplexen Realkomponenten und geometrisch primitiven Prüfkörpern unterscheidet sich signifikant. Daraus können Eigenschaftsunterschiede resultieren, die zu unterschiedlichem Materialverhalten führen können. In diesem Vortrag wird das Konzept repräsentativer Probekörper eingeführt, das eine Übertragung thermischer Historien von komplexen Geometrien auf einfache Geometrien ermöglicht und hierdurch zu einer besseren Vergleichbarkeit der Werkstoffeigenschaften führen soll.
T2 - Schweißen - Österreichs Fachmesse für Füge-, Trenn- und Beschichtungstechnik
CY - Wels, Austria
DA - 23.04.2024
KW - Additive manufacturing
KW - Thermal history
KW - Laboratory specimens
KW - In situ monitoring
KW - Representative specimens
PY - 2024
AN - OPUS4-60261
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Charakterisierung der WIG und FSW-Mischverbindungen neuartiger Multielement-Legierungen mit einem austenitischen Stahl
N2 - Multielement-Legierungen (MPEA - Multiple Principal Element Alloys, gemeinhin auch als Hochentropielegierungen bezeichnet) stellen eine neue Klasse von Werkstoffen dar, die aus mindestens drei Legierungselementen mit jeweils 5 bis 35 Atom-% bestehen. Somit unterscheidet sich diese Legierungskonzept fundamental von konventionellen Werkstoffen wie Stahl oder Nickellegierungen. Hierzu werden die Legierungselemente gezielt ausgewählt und die Mikrostrukturen ein- und zum Teil auch mehrphasig eingestellt. Das Ziel ist dabei, hochinnovative MPEA mit individuell einstellbaren Eigenschaften für die industrielle Anwendung zu identifizieren. Dabei werden insbesondere Zielkonflikte, wie bspw. der Trade-off zwischen Festigkeit und Duktilität bei konventionellen Stählen, überwunden. Insbesondere die hohe mechanische Festigkeit bei höchster Korrosionsbeständigkeit sind bei bestimmten Legierungssystemen von hohem Interesse. Hier kann u.a. die Substitution klassischer hochlegierter Stähle oder von Ni-Basislegierungen perspektivisch erfolgen. In den letzten 20 Jahren lag der Fokus jedoch auf der reinen Materialsynthese. Mit der Zunahme verfügbarer Werkstoffquantitäten, stehen Verarbeitungsfragen, wie werkstoff- und beanspruchungsgerechte Füge- bzw. Schweißverfahren jetzt im Mittelpunkt. Der Schweißeignung von MPEA wurde bis Ende 2022 nur äußert wenig Aufmerksamkeit zuteil. Erfahrungen zu Mischverbindungen (sogenannte DMWs - Dissimilar Metal Welds) fehlen dabei vollständig, sind jedoch essenziell für die Anwendung dieser Werkstoffe in Verbindung mit konventionellen Werkstoffen. Die vorliegende Studie präsentiert erstmals im deutschen Sprachraum, die umfassenden experimentellen Ergebnisse zur Schweißeignung von MPEA-Mischverbindungen und der resultierenden Mikrostruktur. Dazu wurden zwei äquiatomare MPEAs CoCrFeMnNi (Hochentropie-) und CoCrNi (Mittelentropielegierung) mittels WIG- und Rührreibschweißen mit einem konventionellen, hochlegierten und austenitischen Cr-Ni-Stahl (1.4301) gefügt. Die erstmals untersuchten DMWs resultierten dabei in sehr interessanten Mikrostrukturen, mechanisch-technologische Eigenschaften wurden durch instrumentierte Zugversuche gewonnen, die gleichzeitig der Ermittlung der lokalen Verformung im Schweißnahtbereich dienten (durch Verwendung der berührungslosen DIC-Digital Image Correlation-Technik). Dabei zeigt sich für beide Schweißverfahren eine Erweichung in der WEZ der MPEAs sowie eine geringfügig verminderte Zugfestigkeit. Durch die Experimente konnte der prinzipielle Nachweis der Schweißeignung der MPEAs für DMWs mit konventionellen Werkstoffen erbracht werden, die auch eine dementsprechende mechanische Beanspruchbarkeit ermöglichen. Dies ermöglicht zielgerichtete weitere Betrachtungen dieser höchst innovativen Werkstoffe.
T2 - DVS Congress 2023
CY - Essen, Germany
DA - 11.09.2023
KW - Hochentropiewerkstoff
KW - Schweißen
KW - Rührreibschweißen
KW - Mechanische Eigenschaften
KW - Digitale Bildkorrelation (DIC)
PY - 2023
AN - OPUS4-58306
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Dissimilar metal TIG weld joints of multiple principal element alloys (MPEA) to austenitic steel 304
N2 - Multi-element alloys (MPEA - Multiple Principal Element Alloys) represent a new class of materials consisting of at least three alloying elements, each with 5 to 35 atomic %. This material class includes high-entropy alloys (HEA, with n ≥ 4 elements). The underlying alloying concept differs fundamentally from conventional materials such as the Fe-based steel. For this purpose, the alloying elements are specifically selected, and the microstructures are adjusted in a single-phase and, in some cases, multi-phase manner. The aim is to identify highly innovative MPEA with individually adjustable properties for industrial applications. In the last 20 years, however, the focus has been on pure material synthesis. With the increase in available material quantities, the focus is on processing issues such as joining and welding processes. In that connection, the weldability of MPEAs has received very little attention so far. Experience with dissimilar metal welds (DMWs) is completely lacking but is essential for the application of these materials if joint to conventional materials. This study presents selected experimental results on the weldability of MPEA-DMWs and the resulting microstructures. For this purpose, the equiatomic CoCrFeMnNi (HEA) was investigated in cold-rolled (CR) and heat-treated (HT) condition and joined by tungsten inert gas (TIG) welding to an austenitic stainless steel 304. The DMWs showed defect-free conditions (no lack of fusion, cracks and so on), whereas the cold-rolling increases the microhardness. The global mechanical properties were obtained by instrumented tensile tests of cross-weld samples and showed sufficient yield and tensile strength comparable to that of the individual base materials (BM). The local strain conditions were determined by digital image correlation and showed the highest local strains to occur in the intermixed weld metal. Indeed, the preferred fracture location of the cross-weld tensile samples was in the weld metal. Finally, the experiments proofed the weldability of the MPEAs to conventional 304. This enables targeted further considerations for example as structural materials.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 04.09.2023
KW - Multi-principal element alloys
KW - TIG welding
KW - Dissimilar metal weld (DMW) joint
KW - Microstructure
KW - Mechanical properties
KW - Digital Image Correlation (DIC)
PY - 2023
AN - OPUS4-58222
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monavari, Mahshid
A1 - Homaeigohar, Shahin
A1 - Medhekar, Rucha
A1 - Nawaz, Qaisar
A1 - Monavari, Mehran
A1 - Zheng, Kai
A1 - Boccaccini, Aldo R.
T1 - A 3D-Printed Wound-Healing Material Composed of Alginate Dialdehyde–Gelatin Incorporating Astaxanthin and Borate Bioactive Glass Microparticles
N2 - In this study, a wound dressing composed of an alginate dialdehyde−gelatin (ADA-GEL) hydrogel incorporated by astaxanthin (ASX) and 70B (70:30 B2O3/CaO in mol %) borate bioactive glass (BBG) microparticles was developed through 3D printing. ASX and BBG particles sti.ened the composite hydrogel construct and delayed its in vitro degradation compared to the pristine hydrogel construct, mainly due to their cross-linking role, likely arising from hydrogen bonding between the ASX/BBG particles and ADA-GEL chains. Additionally, the composite hydrogel construct could hold and deliver ASX steadily. The composite hydrogel constructs codelivered biologically active ions (Ca and B) and ASX, which should lead to a faster, more e.ective wound-healing process. As shown through in vitro tests, the ASX-containing composite hydrogel promoted fibroblast (NIH 3T3) cell adhesion, proliferation, and vascular endothelial growth factor expression, as well as keratinocyte (HaCaT) migration, thanks to the antioxidant activity of ASX, the release of cell-supportive Ca2+ and B3+ ions, and the biocompatibility of ADA-GEL. Taken together, the results show that the ADA-GEL/BBG/ASX composite is an attractive biomaterial to develop multipurposed wound-healing constructs through 3D printing.
KW - General Materials Science
PY - 2023
DO - https://doi.org/10.1021/acsami.2c23252
SP - 1
EP - 12
PB - American Chemical Society (ACS)
AN - OPUS4-58548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Erxleben, Kjell
A1 - Richter, Tim
A1 - Schröpfer, Dirk
T1 - Charakterisierung der WIG und FSW-Mischverbindungen neuartiger Multielement-Legierungen mit einem austenitischen Stahl
N2 - Multielement-Legierungen (MPEA - Multiple Principal Element Alloys), gemeinhin und partiell fälschlicherweise auch als Hochentropielegierungen bezeichnet) stellen eine neue Klasse von Werkstoffen dar, die aus mindestens drei Legierungselementen mit jeweils 5 bis 35 Atom-% bestehen. Somit unterscheidet sich dieses Legierungskonzept fundamental von konventionellen Werkstoffen wie Stahl oder Nickellegierungen. Hierzu werden die Legierungselemente gezielt ausgewählt und die Mikrostrukturen ein- und zum Teil auch mehrphasig eingestellt. Das Ziel ist dabei, hochinnovative MPEA mit individuell einstellbaren Eigenschaften für die industrielle Anwendung zu identifizieren. Dabei werden insbesondere Zielkonflikte, wie bspw. der Trade-off zwischen Festigkeit und Duktilität bei konventionellen Stählen, überwunden. Insbesondere die hohe mechanische Festigkeit bei höchster Korrosionsbeständigkeit sind bei bestimmten Legierungssystemen von hohem Interesse. Hier kann u.a. die Substitution klassischer hochlegierter Stähle oder Ni-Basislegierungen perspektivisch erfolgen. In den letzten 20 Jahren lag der Fokus jedoch auf der reinen Materialsynthese. Mit der Zunahme verfügbarer Werkstoffquantitäten, stehen Verarbeitungsfragen, wie werkstoff- und beanspruchungsgerechte Füge- bzw. Schweißverfahren jetzt im Mittelpunkt. Der Schweißeignung von MPEA wurde bisher nur äußert wenig Aufmerksamkeit zuteil. Erfahrungen zu Mischverbindungen
(DMWs - Dissimilar Metal Welds) fehlen dabei vollständig, sind jedoch essenziell für die Anwendung dieser Werkstoffe in Verbindung mit konventionellen Werkstoffen. Die vorliegende Studie präsentiert erstmals im deutschen Sprachraum, die umfassenden experimentellen Ergebnisse zur Schweißeignung von MPEA-Mischverbindungen und der resultierenden Mikrostruktur. Dazu wurden zwei äquiatomare MPEAs in Form einer Co20Cr20Fe20Mn20Ni20 (Hochentropie-) und Co33.3Cr33.3Ni33.3 (Mediumentropielegierung) mittels WIG und Rührreibschweißen mit einem konventionellen, korrosionsbeständigem Cr-Ni-Stahl AISI 304 (1.4301 bzw. X5CrNi18-10) gefügt. Die erstmals untersuchten DMWs resultierten dabei in sehr interessanten Mikrostrukturen, mechanisch-technologische Eigenschaften wurden durch instrumentierte Zugversuche gewonnen, die gleichzeitig der Ermittlung der lokalen Verformung im Schweißnahtbereich dienten (durch Verwendung der berührungslosen DIC-Digital Image Correlation-Technik). Dabei zeigt sich für beide Schweißverfahren eine Erweichung in der Wärmeeinflusszone (WEZ) der MPEAs sowie eine geringfügig verminderte Zugfestigkeit, bei einer deutlichen Abnahme der Bruchdehnung. Durch die Experimente konnte der prinzipielle Nachweis der Schweißeignung der MPEAs für DMWs mit konventionellen Werkstoffen erbracht werden, die auch eine dementsprechende mechanische Beanspruchbarkeit ermöglichen. Dies ermöglicht weitere Betrachtungen zur Anwendung dieser innovativen Werkstoffe.
T2 - DVS Congress 2023
CY - Essen, Germany
DA - 11.09.2023
KW - Schweißeignung
KW - Mischverbindung
KW - Hochentropielegierung
KW - Multielement-Legierung
KW - FSW
KW - WIG
PY - 2023
SN - 978-3-96144-230-0
VL - 389
SP - 615
EP - 623
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-58352
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Xinyue
A1 - Dong, Ximan
A1 - Zhang, Chuyan
A1 - Zhu, Meng
A1 - Ahmed, Essraa
A1 - Krishnamurthy, Giridharan
A1 - Rouzbahani, Rozita
A1 - Pobedinskas, Paulius
A1 - Gauquelin, Nicolas
A1 - Jannis, Daen
A1 - Kaur, Kawaljit
A1 - Hafez, Aly Mohamed Elsayed
A1 - Thiel, Felix
A1 - Bornemann, Rainer
A1 - Engelhard, Carsten
A1 - Schönherr, Holger
A1 - Verbeeck, Johan
A1 - Haenen, Ken
A1 - Jiang, Xin
A1 - Yang, Nianjun
T1 - Interlayer Affected Diamond Electrochemistry
N2 - Diamond electrochemistry is primarily influenced by quantities of sp3‐carbon, surface terminations, and crystalline structure. In this work, a new dimension is introduced by investigating the effect of using substrate‐interlayers for diamond growth. Boron and nitrogen co‐doped nanocrystalline diamond (BNDD) films are grown on Si substrate without and with Ti and Ta as interlayers, named BNDD/Si, BNDD/Ti/Si, and BNDD/Ta/Ti/Si, respectively. After detailed characterization using microscopies, spectroscopies, electrochemical techniques, and density functional theory simulations, the relationship of composition, interfacial structure, charge transport, and electrochemical properties of the interface between diamond and metal is investigated. The BNDD/Ta/Ti/Si electrodes exhibit faster electron transfer processes than the other two diamond electrodes. The interlayer thus determines the intrinsic activity and reaction kinetics. The reduction in their barrier widths can be attributed to the formation of TaC, which facilitates carrier tunneling, and simultaneously increases the concentration of electrically active defects. As a case study, the BNDD/Ta/Ti/Si electrode is further employed to assemble a redox‐electrolyte‐based supercapacitor device with enhanced performance. In summary, the study not only sheds light on the intricate relationship between interlayer composition, charge transfer, and electrochemical performance but also demonstrates the potential of tailored interlayer design to unlock new capabilities in diamond‐based electrochemical devices.
KW - Nanocrystalline diamond
KW - Interfaces
KW - Electrochemistry
KW - TOF-SIMS
KW - SEM
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621576
DO - https://doi.org/10.1002/smtd.202301774
SN - 2366-9608
VL - 9
IS - 2
SP - 1
EP - 10
PB - Wiley VHC-Verlag
CY - Weinheim
AN - OPUS4-62157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
A1 - Engelking, Lorenz
T1 - Bericht aus DVS Vorhaben 01.3211: Schweißzusatzmodifikation zur Gefüge und Eigenschaftsoptimierung bei kombinierter additiver und zerspanender Fertigung hochbelasteter Bauteile
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Es wird eine kurze Übersicht über die bisher erzielten Ergebnisse gegeben. Thematisiert wird sowohl die Mikrostruktur und Härte als auch Ergebnisse der Zerspanbarkeit hinsichtlich der resultierenden Zerspankraft, der Temperatur sowie der erzielten Rauheit unterschiedlicher Modifikationen der FeNi36- und der CoCr-Legierung.
T2 - NA 092-00-05 GA "Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)"
CY - Online meeting
DA - 10.03.2022
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2022
AN - OPUS4-54913
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Wear behavior of innovative niobium carbide cutting tools in ultrasonic-assisted finishing milling
N2 - The resources of niobium exceed the ones of tungsten by an order of magnitude. With 92%, Brazil is today the main global producer of niobium. Hence, niobium carbides (NbC) are a sustainable and economic alternative to conventionally used cutting materials, especially tungsten carbides (WC). Moreover, NbC can be used in Ni alloy matrix and thus offer significant advantages by substituting WC in Co matrix as cutting materials in terms of health risks and raw material price and supply risk. Based on recent studies which found an increased performance of NbC compared to WC cutting tools in machining higher strength steels, the composition NbC12Ni4Mo4VC was chosen for finish machining of a high-strength steel S960QL in this study. The experiments were carried out on an ultrasonic-assisted 5-axis milling machine using NbC tools specially made to benchmark them with commercially available coated WC cutting inserts. In addition, the influence of a coating system for the NbC inserts is tested and evaluated for its performance in the cutting process. Tool wear and cutting force analyses are implied to identify optimal parameter combinations as well as tool properties for the novel NbC tool. Together with the oscillation of ultrasonic-assisted milling, the loads on the component surface and the tool can be reduced and the wear behavior of the novel NbC tool can be refined. These milling tests are accompanied by standardized wear tests, i.e., pin-on-disc, between the aforementioned material combinations, and the results are correlated with each other. Finally, the behavior when using hard-to-cut materials such as Ni alloys, or innovative materials such as iron aluminide is also being tested, as these are constantly in the focus of machining optimization. With this strategy, comprehensive knowledge is achievable for future efficient application of NbC for milling tools, which have already been researched for decades using WC.
T2 - 24th International Conference on Wear of Materials
CY - Banff, Canada
DA - 16.04.2023
KW - Cutting tool
KW - Niobium carbide
KW - Tool wear
KW - Ultrasonic-assisted milling
PY - 2023
AN - OPUS4-59258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - WAAM process influences on local microstructure and residual stresses in high-strength steels
N2 - High-strength fine-grain structural steels have great potential for weight optimization of many modern engineering structures. Efficient manufacturing can be achieved here above all by Wire Arc Additive Manufacturing (WAAM). First commercial high-strength welding consumables for WAAM are already available. Due to a lack of knowledge and guidelines for the industry regarding welding residual stresses and component safety in manufacturing and operation, their application is still severely limited. Residual stresses play a crucial role here, as the special microstructure of high-strength steels is sensitive to cold cracking.
For this reason, process- and material-related influences, as well as the design effects on residual stress formation, are being investigated in a project funded by the AiF (FOSTA P1380/IGF 21162 BG). This study focuses on determining the interactions between heat control during WAAM process, resulting hardness, microstructure, and residual stresses, analyzed by X-ray diffraction. Welding experiments using geometrically similar AM specimens show that, with regard to the heat input, the energy per unit length in particular leads to significantly affected cooling times and microstructures and causes pronounced localized effects in terms of residual stresses in the upper weld beads.
T2 - 46th MPA-Seminar
CY - Stuttgart, Germany
DA - 12.10.2021
KW - Wire Arc Additive Manufacturing
KW - High-strength structural steels
KW - Vickers hardness
KW - Residual stresses
PY - 2021
AN - OPUS4-53567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Zum Einfluss der Wärmeführung auf die Eigenschaften und Beanspruchungen bei hybrid-additiver Fertigung hochfester Stähle mittels MSG-Prozessen
N2 - Der Einsatz von Stählen mit höheren Streckgrenzen erlaubt die Reduzierung von Wandstärken, Bauteilgewicht und Fertigungskosten. Mittels hybrid-additiver Fertigung auf Basis von MSG-Schweißverfahren (DED-Arc) können hocheffizient Bauteilmodifikationen und -reparaturen an Halbzeugen sowie (primär) additiv gefertigten Strukturen realisiert werden. Der breiten Anwendung, gerade bei KMU, stehen noch wesentliche Fragestellungen entgegen. Neben der fertigungstechnischen Gestaltung, Aufbaustrategie und geometrischen Bauteiladaption für Modifikatio-nen oder Reparaturen betrifft dies die schweißbedingten Beanspruchungen im Zusammenhang mit den mikrostruk-turellen Einflüssen durch die additiven Fertigungsschritte insbesondere im Anbindungsbereich von Substrat und Schweißzusatzwerkstoff. Hierfür werden in einem gemeinsamen Forschungsprojekt (FOSTA-P1660/IGF22628BG) der BAM und der TU Chemnitz systematisch Kenntnisse zur metallurgischen Auswirkung sowie zu den resultieren-den Spannungen und Dehnungen beim hybrid-additiven MSG-Schweißen von hochfesten Stählen speziell im Übergangsbereich zwischen Substrat und additiv gefertigter Struktur erarbeitet. Der vorliegende Beitrag fokussiert die durchgeführten Analysen zur Auswirkung der Wärmeführung der AM-Bauteile auf die Abkühlbedingungen, Gefüge und Eigenspannungen, insbesondere im Anbindungsbereich. Hierfür wurden definierte Probenkörper vollautomatisiert mit einem hochfesten speziell für DED-Arc angepassten Massivdraht (Streckgrenze > 790 MPa) auf Substrat-Körper aus S690QL-Grundwerkstoff geschweißt und die Arbeitstemperatur sowie die Streckenenergie innerhalb eines Design of Experiments variiert. Hinsichtlich der Schweißwärmeführung wurden t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt. Die Ergebnisse zeigen einen deutlichen Einfluss der Wärmeführung auf die lokalen Eigenspannungen insbesonde-re im Anbindungsbereich. Mit den Ergebnissen lassen sich Verarbeitungsempfehlungen erarbeiten, um DED-Arc-Prozesse für beanspruchungsgerechte und risssichere hybrid-additive Fertigung zur Bauteilmodifizierung und -reparatur zu etablieren. Dies ermöglicht gerade KMU eine wirtschaftliche und ressourcenschonende Fertigung hochfester Stahlkomponenten.
T2 - 6. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - DED-Arc
KW - Eigenspannung
KW - Wärmeführung
PY - 2025
AN - OPUS4-62618
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelhard, Carsten
T1 - On ICP-MS with Nanosecond Time Resolution: From Nanoparticles to Microplastics
N2 - In this presentation, recent developments in inductively coupled plasma mass spectrometry (ICP-MS) instrumentation for particle characterization in complex mixtures will be reviewed. The current state-of-the-art in single-particle (sp) ICP-MS instrumentation for the detection and characterization of nanoparticles (NP) and microplastics (MPs) as well as remaining challenges will be discussed.
While millisecond dwell times were used in the advent of spICP-MS, the use of microsecond dwell times helped to improve nanoparticle data quality and particle size detection limits. We could show that a custom-built high-speed data acquisition unit with microsecond time resolution (μsDAQ) can be used to successfully address issues of split-particle events and particle coincidence, to study the temporal profile of individual ion clouds, and to extend the linear dynamic range by compensating for dead time related count losses.
Our latest development is an in-house built data acquisition system with nanosecond time resolution (nanoDAQ). Recording of the SEM signal by the nanoDAQ is performed on the nanosecond time scale with a dwell time of approximately 2 ns and enables detection of gold nanoparticles (AuNP) as small as 7.5 nm with a commercial single quadrupole ICP-MS instrument. [1] Analysis of acquired transient data is based on the temporal distance between detector events and a derived ion event density. It was shown that the inverse logarithm of the distance between detector events is proportional to particle size. Also, the number of detector events per particle can be used to calibrate and determine the particle number concentration (PNC) of a nanoparticle dispersion. In addition to inorganic nanoparticles, first results on the detection of microplastics with spICP-MS will be discussed.
T2 - ANAKON 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Nano
KW - Microplastics
KW - Nanoparticle Characterization
KW - ICP-MS
KW - Instrumentation
PY - 2025
AN - OPUS4-63580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelhard, Carsten
T1 - From Particles to PFAS: Recent Advances in Plasma-based Instrumentation Development
N2 - In this presentation, recent advances in plasma spectrochemistry with hot and cold plasma sources for the direct detection of nanoparticles as well as per- and polyfluoroalkyl substances (PFAS) will be discussed. In the first part, single-particle inductively coupled plasma mass spectrometry (spICP-MS) with an in-house built data acquisition system with nanosecond time resolution (nanoDAQ) will be presented. In the second part, we turn to a cooler plasma source. Specifically, a flowing atmospheric-pressure afterglow source (FAPA) and its application for the direct mass spectrometric analysis of PFAS will be discussed.
T2 - 20th European Winter Conference on Plasma Spectrochemistry
CY - Berlin, Germany
DA - 02.03.2025
KW - ICP-MS
KW - Instrumentation
KW - Nano
KW - Nanoparticle Characterization
KW - PFAS
PY - 2025
AN - OPUS4-63581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Einfluss der Wärmeführung auf die Eigenschaften und fertigungsbedingten Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle
N2 - Hochfeste Feinkornbaustähle verfügen über ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Kommerzielle hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Derzeit ist jedoch eine breite industrielle Anwendung insbesondere für KMU aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse untersucht. Im Fokus dieser Analysen steht die Bestimmung der Wechselwirkungen zwischen WAAM-Prozessparametern bzw. der Wärmeführung auf das Gefüge und die Eigenspannungen. Hierfür werden Referenzproben als offene Hohlquader mit definierten Abmessungen vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die gezielte Einstellung der geometrischen Eigenschaften erfolgt durch Schweißparameter und Nahtaufbau bei ca. 4 kg/h mittlerer Abschmelzleistung. Die Wärmeführung wird innerhalb eines statistischen Versuchsplanes mittels Streckenenergie (200 kJ/m bis 650 kJ/m) und Zwischenlagentemperatur (100 °C bis 300 °C) so variiert, dass die t8/5-Abkühlzeiten dem empfohlenen Verarbeitungsbereich entsprechen (ca. 5 s bis 20 s). Ziel ist es bei konstanten geometrisch-konstruktiven Randbedingungen, den Einfluss der Wärmeführung auf Gefüge und resultierende Eigenspannungen zu analysieren. Für die Streckenenergie können neben den Gefügeeinflüssen aufgrund der resultierenden Abkühlzeit deutliche Effekte insbesondere auf die lokalen Eigenspannungen im Bauteil belegt werden. Das Schweißen mit zu hoher Wärmeeinbringung bzw. Abschmelzleistung kann zu ungünstigen Gefüge- und Bauteileigenschaften führen, gleichzeitig jedoch niedrigere Zugeigenspannungsniveaus bewirken. Solche komplexen Wechselwirkungen gilt es letztlich mit diesen Untersuchungen zu klären, um leicht anwendbare Verarbeitungsempfehlungen und Normvorgaben für ein wirtschaftliches, anforderungsgerechtes und risssicheres WAAM von hochfesten Stählen den Anwendern zur Verfügung zu stellen.
T2 - DVS Congress 2021
CY - Online meeting
DA - 14.09.2021
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Kaltrisssicherheit
KW - Hochfester Stahl
PY - 2021
AN - OPUS4-56668
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Zum Einfluss der Wärmeführung auf die Eigenschaften und Beanspruchungen bei hybrid-additiver Fertigung hochfester Stähle mittels MSG-Prozessen
N2 - Der Einsatz von Stählen mit höheren Streckgrenzen erlaubt die Reduzierung von Wandstärken, Bauteilgewicht und Fertigungskosten. Mittels hybrid-additiver Fertigung auf Basis von MSG-Schweißverfahren (DED-Arc) können hocheffizient Bauteilmodifikationen und -reparaturen an Halbzeugen sowie (primär) additiv gefertigten Strukturen realisiert werden. Der breiten Anwendung, gerade bei KMU, stehen noch wesentliche Fragestellungen entgegen. Neben der fertigungstechnischen Gestaltung, Aufbaustrategie und geometrischen Bauteiladaption für Modifikatio-nen oder Reparaturen betrifft dies die schweißbedingten Beanspruchungen im Zusammenhang mit den mikrostruk-turellen Einflüssen durch die additiven Fertigungsschritte insbesondere im Anbindungsbereich von Substrat und Schweißzusatzwerkstoff. Hierfür werden in einem gemeinsamen Forschungsprojekt (FOSTA-P1660/IGF22628BG) der BAM und der TU Chemnitz systematisch Kenntnisse zur metallurgischen Auswirkung sowie zu den resultieren-den Spannungen und Dehnungen beim hybrid-additiven MSG-Schweißen von hochfesten Stählen speziell im Übergangsbereich zwischen Substrat und additiv gefertigter Struktur erarbeitet. Der vorliegende Beitrag fokussiert die durchgeführten Analysen zur Auswirkung der Wärmeführung der AM-Bauteile auf die Abkühlbedingungen, Gefüge und Eigenspannungen, insbesondere im Anbindungsbereich. Hierfür wurden definierte Probenkörper vollautomatisiert mit einem hochfesten speziell für DED-Arc angepassten Massivdraht (Streckgrenze > 790 MPa) auf Substrat-Körper aus S690QL-Grundwerkstoff geschweißt und die Arbeitstemperatur sowie die Streckenenergie innerhalb eines Design of Experiments variiert. Hinsichtlich der Schweißwärmeführung wurden t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt. Die Ergebnisse zeigen einen deutlichen Einfluss der Wärmeführung auf die lokalen Eigenspannungen insbesonde-re im Anbindungsbereich. Mit den Ergebnissen lassen sich Verarbeitungsempfehlungen erarbeiten, um DED-Arc-Prozesse für beanspruchungsgerechte und risssichere hybrid-additive Fertigung zur Bauteilmodifizierung und -reparatur zu etablieren. Dies ermöglicht gerade KMU eine wirtschaftliche und ressourcenschonende Fertigung hochfester Stahlkomponenten.
T2 - NA 092-00-05 GA Gemeinschaftsarbeitsausschuss NAS/NMP, Zerstörende Prüfung von Schweißverbindungen
CY - Online meeting
DA - 20.03.2025
KW - DED-Arc
KW - Eigenspannung
KW - Wärmeführung
PY - 2025
AN - OPUS4-62746
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Schröpfer, Dirk
A1 - Becker, Amadeus
A1 - Kannengießer, Thomas
T1 - Beanspruchungsgerechte Reparatur von Schweißverbindungen bei der Fertigung von Bauteilen aus hochfesten Feinkornbaustählen
N2 - Bei der Montage von Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich. Die Verarbeitungsregelwerke empfehlen das lokale thermische Ausfugen betroffener Bereiche und erneutes Schweißen, geben aber aufgrund fehlender wissenschaftlich fundierter Untersuchungen kaum Informationen zu adäquaten Reparaturkonzepten. Dies betrifft insbesondere die Berücksichtigung und Optimierung resultierender schweißbedingter Beanspruchungen durch hohe Schrumpfbehinderungen der Ausfugenuten sowie der Gefügedegradation angrenzender Bereiche durch das Ausfugen und erneute Schweißen. Gerade bei hochfesten Stahlgüten ergeben sich dadurch häufig reduzierte mechanische Eigenschaften und zusätzliche schweißbedingte Beanspruchungen sowie erneut auftretende Nahtdefekte.
Deshalb wurden für das Forschungsvorhaben systematische bauteilrelevante Untersuchungen der schweißbedingten Beanspruchungen und Gefügeveränderungen reparierter Schweißnähte in Abhängigkeit von der Schrumpfbehinderung und Wärmeführung beim Schweißen und Ausfugen sowie von der Reparaturzyklenanzahl durchgeführt. Die Untersuchungsergebnisse zeigen auf, welche Faktoren sich für eine Beanspruchungsreduzierung auch bei hohen Einspannbedingungen eignen und wie eine Degradation des Gefüges und der Eigenschaften der Schweißnaht sowie wiederholte Schweißnahtdefekte in der Reparaturnaht vermieden werden können. Insbesondere können mittels adaptiver Wärmeführung geringere schweißbedingte Beanspruchungen in den Reparaturschweißnähten bewirkt werden. Bauteilversuche sichern zudem die Übertragbarkeit der Schweißexperimente in die Praxis ab.
Aufgrund der Erkenntnisse konnten Empfehlungen für beanspruchungs- und werkstoffgerechte Reparaturkonzepte abgeleitet und ausgesprochen werden. Die Analysen wurden an den hochfesten Stahlgüten S500MLO für den Offshore-Bereich und S960QL für den Mobilkranbau realisiert. Damit wird insbesondere der wirtschaftlichen Fertigung hocheffizienter Konstruktionen für Windenergieanlagen und hochfester Strukturen, die für deren Errichtung notwendig sind, Rechnung getragen.
So bieten die Forschungsergebnisse eine wesentliche Grundlage für die Weiterentwicklung entsprechender Normen und Regelwerke. Damit können letztlich Schäden und zumeist teure Nacharbeiten verhindert und eine verbesserte Ausnutzung des hohen Festigkeitspotentials hochfester Stähle erreicht werden. Gerade auch KMU können mit Blick auf die Kosten für Fertigung, Schweißarbeit und Material von den Erkenntnissen beim Einsatz hochfester Stähle, die für eine effiziente Realisierung der Energiewende in Deutschland notwendig sind, profitieren.
KW - MAG-Schweißen
KW - Hochfester Stahl
KW - Reparatur
KW - Kaltrisssicherheit
KW - Reparaturschweißen
KW - Wärmeführung
KW - Windenergie
PY - 2023
UR - https://matplus.shop/produkt/p-1311-beanspruchungsgerechte-reparatur-von-schweissverbindungen-bei-der-fertigung-von-bauteilen-aus-hochfesten-feinkornbaustaehlen
SN - 978-3-96780-146-0
N1 - Schlussbericht vom 18.07.2022 zu dem über die Arbeitsgemeinschaft industrieller Forschungsvereinigungen "Otto von Guericke" (AiF) im Rahmen des Programms zur Förderung der Industriellen Gemeinschaftsforschung und -entwicklung (IGF) vom Bundesministerium für Wirtschaft und Energie (BMWi) aufgrund eines Beschlusses des Deutschen Bundestages geförderten Vorhaben Nr. 20162 N (Berichtszeitraum 01.07.2019 - 28.02.2022)
VL - P 1311
SP - 1
EP - 156
PB - Verlag und Vertriebsgesellschaft
CY - Düsseldorf
AN - OPUS4-59260
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
T1 - Effect of alloy modification for additive manufactured Ni alloy components on microstructure and subsequent machining properties
N2 - Ni alloys are generally classified as difficult-to-cut materials and cost intensive. Additive manufacturing (AM) offers economic advantages. However, machining of these AM components is mandatory to create the final contour or surface. The inhomogeneous and anisotropic microstructure and properties of AM components causes an unstable cutting process. Moreover, undesirable tensile residual stresses are generated due to subsequent machining. In this investigation, the initial alloy 36 is modified with Ti and Nb up to 1.6 wt.-% and build-up welded via gas metal arc welding (GMAW) and plasma-transferred-arc (PTA). Then, finish-milling tests are carried out to investigate the influence of the modification as well as the cutting parameters on the resulting cutting force and the surface integrity. In addition, the conventional milling process (CM) is compared with the ultrasonic-assisted milling process (US), which has a significant influence on the machinability as well as on the surface integrity.
T2 - Additive Fertigung – Werkstoffe – Prozesse – Wärmebehandlung 2022
CY - Bremen, Germany
DA - 29.06.2022
KW - Additive manufacturing
KW - Alloy 36
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
SP - 57
EP - 67
AN - OPUS4-55430
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Legierungsmodifikation und Einsatz hybrider Fräsprozesse zur Optimierung der Zerspanungssituation Ni-basierter Verschleißschutzauftragschweißungen mit definierten Oberflächen
N2 - Die Ziele zur Verringerung der CO2-Emissionen sind eng verknüpft mit der Entwicklung hocheffizienter und wirtschaftlicher Komponenten aus Stahl in der Anlagen-, Verfahrens- und Kraftwerktechnik, die für hohe kombinierte korrosive, tribologische, thermische und mechanische Beanspruchungen auf Anwendungsfall und Stahlwerkstoff abgestimmte Verschleißschutzschichten erfordern. Neben zunehmenden Forderungen infolge des Preis- und Lieferrisikos konventionelle Kobalt- durch Nickellegierungen zu ersetzen, wächst in der Industrie der Bedarf nach definierten Oberflächen hoher Güte bzw. Funktionsflächen für die Schutzschichten. Eine für Bauteile mit komplexer Geometrie erforderliche Fräsbearbeitung ist insbesondere für KMU aufgrund hohen Werkzeugverschleißes oftmals nicht wirtschaftlich realisierbar, jedoch für viele Einsatzfälle dringend notwendig.
In einem Gemeinschaftsvorhaben der BAM und des ISAF der TU Clausthal (Fosta P1550/IGF 21959 N) wird daher untersucht, wie mittels Legierungsmodifikationen der Schweißzusätze für nickelbasierte plasmaauftraggeschweißte Verschleißschutzschichten und durch Einsatz innovativer ultraschallunterstützter Fräsprozesse eine günstigere Zerspanbarkeit erreicht werden kann, ohne das Verschleißschutzpotential zu mindern.
Im vorliegenden Beitrag wird der Einfluss der mittels Legierungsmodifikation eingestellten Gefüge- und Ausscheidungsmorphologie auf die Zerspanung untersucht. Dies erfolgt anhand einer typischerweise für Schneckenmaschinen eingesetzte Verschließschutzlegierung zur Substitution entsprechender CoCr-Legierungen (Stellite), einer NiCrMoSiFeB-Legierung (Handelsname: Colmonoy 56 PTA). Durch metallurgische Untersuchungen und In-situ-Messung auftretender Prozesskräfte und Temperaturen an der Werkzeugschneide beim Fräsprozesses sowie der anschließenden Untersuchung von Werkzeugverschleiß und Oberflächenintegrität ist eine detaillierte Analyse und Korrelation zwischen den mikrostrukturellen Eigenschaften und der Zerspanbarkeit möglich. Die Vorgehensweise erlaubt einer Beurteilung des Einflusses der ultraschallunterstützten Fräsbearbeitung auf den Prozess sowie die resultierenden Oberflächenintegrität. Unter systematischer Anwendung dieser Methodik sowie der Berücksichtigung der Anbindung zum Stahlsubstratwerkstoff und der Wirksamkeit des Verschleißschutzes lässt sich letztlich eine gezielte Optimierung der Zerspanungssituation und des Verschleißschutzes erreichen. Die Erkenntnisse erlauben Handlungsanweisungen und Empfehlungen für Normen und Verarbeitungsrichtlinien, die besonders KMU eine sichere und wirtschaftliche Fertigung hochbelasteter Stahlkomponenten mit unkritischen, kostenreduzierten Werkstoffen ermöglichen sollen.
T2 - DVS Congress 2023
CY - Essen, Germany
DA - 11.09.2023
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
KW - Zerspankräfte
PY - 2023
AN - OPUS4-59209
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Generative Fertigung und Kaltrisssicherheit
N2 - Hochfeste Feinkornbaustähle verfügen über ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. In dieser Präsentation werden erste Ergebnisse der Eigenspannungsanalysen von additiv gefertigten Bauteilen aus hochfestem Stahl vorgestellt.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Online meeting
DA - 10.06.2021
KW - Additive Fertigung
KW - Wärmeführung
KW - Hochfester Stahl
KW - Eigenspannungen
KW - Härteprüfung nach Vickers
PY - 2021
AN - OPUS4-53326
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
T1 - Repair welding of pressurized in-service hydrogen pipelines: A review on current challenges and strategies
N2 - As energy carrier of the future, green hydrogen can make a decisive contribution to a sustainable energy supply. Particularly important is the decarbonization of heavy industry. Therefore, a reliable supply of hydrogen must be guaranteed. A hydrogen pipeline grid can achieve this purpose. In Europe concrete plans for a hydrogen pipeline grid already exist, as the so called “European Hydrogen backbone”. As building a completely new pipeline grid is economically not justifiable, a dual-way strategy of repurposing natural gas (NG) pipelines and newly built pipelines is intended.
Long distance pipeline grids require regular maintenance and repairs. For NG pipelines in-service welding is state of the art. Concepts such as hot-tapping (drilling into pressurized pipelines) and “stoppling” (sealing off pipeline sections after installing bypasses or pressure relieves) allow the repair of damaged pipeline sections or the installation of new branches without shutting the pipeline down, which in most cases isn’t possible from an economic standpoint.
The EIGA 121/14 guideline already pointed out in 2014 that “A hydrogen hot-tap shall not be considered a rou-tine procedure, […]”. This shows that the determination of the transferability of these repair concepts to hydrogen pipelines is of utmost importance. Due to the degrading effects of hydrogen on mechanical properties, commonly referred to as “hydrogen embrittlement” it is necessary to understand and investigate the occurring effects. In the special case of repair welding on in-service hydrogen pipelines an increased hydrogen uptake due to a large heat input and microstructural changes in the material needs to be considered. Therefore, material degradation must be investigated to determine whether modifications of repair procedures are necessary to ensure a reliable and safe hydrogen transportation via pipelines.
For this reason, this paper gives an overview on existing weld repair concepts and its risks and limitations in terms of hydrogen absorption and possible embrittlement effects when transferred to hydrogen pipelines. The complexity lies in a large variety of materials (low alloyed steels), pipeline diameters and corresponding weld-ed joints. The material compatibility of materials in used (repurposed NG-pipelines) and new condition must be investigated. Particularly for repurposed/used pipelines the effect of a pre-matured/corroded inner surface and sometimes insufficient documentation of the material “history” needs to be considered.
An overview on ongoing and completed R&D-projects with respect to repair concepts for hydrogen pipelines and hydrogen effects on pipeline materials is given.
T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission II-A "Metallurgy of Weld Metals"
CY - Ixia, Rhodes Island, Greece
DA - 07.07.2024
KW - Hydrogen
KW - Pipeline
KW - In-Service Welding
PY - 2024
AN - OPUS4-60757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Czeskleba, Denis
T1 - Entwicklung von Wärmenachbehandlungskonzepten zur Vermeidung von spannungsrelaxationsrissen
N2 - Vorstellung des Projekts Vh_9475 im Rahmen eines Kolloquiums der OVGU Magdeburg. In diesem Projekt wird erforscht, welchen Einfluss die PWHT-Parameter Aufheizrate und Haltetemperatur auf die Rissanfälligkeit von 13CrMoV9-10 haben. Diese Präsentation stellt den aktuellen Projektstand dar, gibt eine Übersicht über die Rissentstehung und wie die Forschungsstelle bei ihren Forschungen zu diesem Projekt vorgeht. Gleichzeitig wurde die Versuchstechnik vorgestellt und insbesondere die neue UP-Schweißanlage präsentiert.
T2 - BMDK
CY - Online meeting
DA - 18.11.2020
KW - Spannungsrelaxationsrisse
KW - 13CrMoV9-10
KW - PWHT
KW - BMDK
KW - Aufheizrate
PY - 2020
AN - OPUS4-51583
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
A1 - Hadick, C.
A1 - Schu, K.
T1 - Quantification of hydrogen uptake during in-service hydrogen pipeline welding
N2 - Hydrogen must be transported on a large scale from producers to consumers to ensure the energy transition. The necessary pipeline grid is achieved by conversion of the natural gas (NG) grid and building new pipelines. Welding during service as part e.g. of “hot-tapping” is unavoidable for maintenance/repair/expansion. Based on existing studies, the basic material compatibility of (low-alloyed) pipeline steels with hydrogen is postulated. However, this cannot be assumed for the case of in-service welding on pipelines in pressurized condition. The reason is the increased temperature e.g. by preheating and (in particular) during welding of the single passes. As a result, the inner pipeline surface undergoes multiple short-term heating but to high temperatures. In particular, the first passes can result in a temperature close to the austenitic transformation of the material for small wall thicknesses. Both increase the hydrogen uptake into the welded joint. If hydrogen embrittlement is likely to occur, depends on the hydrogen uptake, which must be quantified. For this purpose, welding experiments on pressurized demonstrators were conducted. The hydrogen uptake at 100 bar was compared to reference experiments with nitrogen. A new sample extraction routine for the quantification of the weld-zone specific hydrogen uptake was established. Comprehensive experiments with different steels (P235, L360, L485), wall thicknesses (4.1 mm to 7.8 mm) and diameters (DN50 and DN200) were conducted. In addition, the influence of the welding layer sequence on the hydrogen uptake between single- and multi-layer welds was investigated. Analytical approaches were used to approximate the hydrogen uptake in the respective weld zones. The main findings were that the layer sequence and especially the wall thickness have a large influence on the hydrogen uptake.
T2 - 20th Pipeline Technology Conference ptc2025
CY - Berlin, Germany
DA - 06.05.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Repair welding
KW - component test
PY - 2025
SP - 1
EP - 12
AN - OPUS4-63166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Large scale hydrogen assisted cracking test for thick walled SAW joints for offshore applications
N2 - Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods or jackets. These components are typically submerged arc welded (SAW) high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicate the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam / layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled more than 20 passes and a seam length of 1,000 mm. Additional welded stiffeners simulated the effect of a high restraint, to stimulate critical HAC conditions. The necessity of a minimum waiting time (MWT) before the NDT can be conducted (to exclude HAC) was critically verified by the application of ultrasonic testing of the welded joint at different time-steps of the NDT of 48 h after welding. The residual stresses were determined by a robot XRD goniometer. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modelling allowed the qualitative estimation of the hydrogen diffusion in the weld. A remarkable HAC occurrence was not identified and proves both, a certain resistance of the weld joint to HAC and the (questionable) duration of the MWT.
T2 - IIW Intermediate Meeting of Commission II-A
CY - Garching, Germany
DA - 06.03.2023
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - Offshore wind turbine
KW - High-strength steel
KW - Component test
PY - 2023
AN - OPUS4-57100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmitt, Johannes
T1 - Data acquisition system for single particle inductively coupled plasma mass spectrometry (spICP-MS) with nanosecond time resolution
N2 - This study presents our data acquisition system prototype for single particle inductively coupled plasma mass spectrometry (spICP-MS) with nanosecond time resolution (nanoDAQ) and a matching data processing approach for time-resolved data in the nanosecond range. The system continuously samples the secondary electron multiplier (SEM) detector signal with a dwell time of approximately 2 ns and enables detection of gold nanoparticles (AuNP) as small as 7.5 nm with a commercial single quadrupole ICP-MS instrument. [1]
Analysis of acquired transient data is based on the temporal distance between detector events and a derived ion event density. It was shown that the inverse logarithm of the distance between detector events is proportional to particle size. Also, the number of detector events per particle can be used to calibrate and determine the particle number concentration (PNC) of a nanoparticle dispersion. [1]
Particle-by-particle-based analysis of ion event density and other parameters derived from nanosecond time resolution show promising results. High data acquisition frequency of the systems allows recording of a statistically significant number of data points in 60 s or less, which leaves only the sample uptake and rinsing steps as remaining factors for limiting the total measurement time.
T2 - ANAKON 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - ICP-MS
KW - Instrumentation
KW - Nano
KW - Nanoparticle Characterization
PY - 2025
AN - OPUS4-63603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Taparli, Ugur Alp
A1 - Kannengießer, Thomas
A1 - Griesche, Axel
T1 - Tungsten inert gas bead-on-plate weld chemical composition analysis by laser-induced breakdown spectroscopy
N2 - Chemical compositions of a weld can be varying locally as a result of the welding process. These local variations can be due to the vaporization of individual alloying elements. In this work, tungsten inert gas (TIG) bead-on-plate stainless steel welds of EN grade 1.4404 and 1.4435 were investigated using laser-induced breakdown spectroscopy (LIBS) on the completed welds. This study aims to reveal the welding parameters’ influence on the resulting local chemical compositions of the stainless steel welds. We demonstrated Mn vaporize before Cr due to its lower latent enthalpy of vaporization. Hence, Mn accumulates on the heat-affected zone (HAZ) both sides across the weld bead by being swept away through the circulation flow of the welding plasma. Additionally, increasing the heat input tends to enhance the accumulated Mn content on the HAZ as well as increasing the shielding gas flow rate. The results are in good agreement with the literature and proved that LIBS is an effective method to inspect completed welds.
T2 - Symposium on Materials and Joining Technology
CY - Magdeburg, Germany
DA - 07.09.2020
KW - LIBS TIG welding
KW - Austenitic stainless steels
KW - Chemical composition
KW - In situ measurement
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511595
DO - https://doi.org/10.1088/1757-899X/882/1/012023
SN - 1757-8981
SN - 1757-899X
VL - 882
IS - 012023
SP - 1
EP - 8
PB - IOP Publishing
CY - Bristol
AN - OPUS4-51159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Rhode, Michael
A1 - Wimpory, R. C.
A1 - Kannengießer, Thomas
T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part III - Assessment of residual stresses from small-scale to real component welds
N2 - For higher operational temperatures and pressures required in petrochemical plants, the modified 13CrMoV9-10 steel was developed providing high resistance against creep and compressed hydrogen. Extreme care during the welding procedure is necessary for this steel, attributed to low toughness, high strength in as-welded state, and increased susceptibility to stress relief cracking (SRC) during post-weld heat treatment (PWHT). Previous research of SRC in creep-resistant steels discussed mainly thermal and metallurgical factors. Few previous findings addressed the influences of welding procedure on crack formation during PWHT considering real-life manufacturing conditions. These investigations focus on effects of welding heat control on stresses during welding and subsequent PWHT operations close to realistic restraint and heat dissipation conditions using a special 3D testing facility, which was presented in parts I and II of this contribution. Part III addresses investigations on residual stress evolution affecting crack formation and discusses the transferability of results from large-scale testing to laboratory-scale. Experiments with test set-ups at different scales under diverse rigidity conditions and an assessment of the residual stresses of the weld-specimens using X-ray (surface near) and neutron diffraction analysis (bulk) were performed. This study aims to provide a way of investigating the SRC behaviour considering component-specific residual stresses via small-scale testing concepts instead of expensive weld mock-ups.
KW - Welding
KW - Creep-resistant steel
KW - Residual stresses
KW - Post-weld heat treatment
KW - Stress relief cracking
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524403
DO - https://doi.org/10.1007/s40194-021-01101-7
SN - 1878-6669
VL - 65
SP - 1671
EP - 1685
PB - Springer
CY - Berlin
AN - OPUS4-52440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Börner, Andreas
A1 - Gustus, R.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
A1 - Maus-Friedrichs, W.
T1 - Surface finishing of hard-to-machine cladding alloys for highly stressed components
N2 - The supply and processing of materials for highly stressed components are usually cost-intensive. Efforts to achieve cost and resource efficiency lead to more complex structures and contours. Additive manufacturing steps for component repair and production offer significant economic advantages. Machining needs to be coordinated with additive manufacturing steps in a complementary way to produce functional surfaces suitable for the demands. Regarding inhomogeneity and anisotropy of the microstructure and properties as well as production-related stresses, a great deal of knowledge is still required for efficient use by small- and medium-size enterprises, especially for the interactions of subsequent machining of these difficult-to-machine materials. Therefore, investigations on these influences and interactions were carried out using a highly innovative cost-intensive NiCrMo alloy (IN725). These alloys are applied for claddings as well as for additive component manufacturing and repair welding using gas metal arc welding processes. For the welded specimens, the adequate solidification morphology, microstructure and property profile were investigated. The machinability in terms of finishing milling of the welded surfaces and comparative analyses for ultrasonic-assisted milling processes was examined focussing on surface integrity. It was shown that appropriate cutting parameters and superimposed oscillating of the milling tool in the direction of the tool rotation significantly reduce the mechanical loads for tool and workpiece surface. This contributes to ensure a high surface integrity, especially when cutting has to be carried out without cooling lubricants.
KW - WAAM
KW - IN725
KW - Machining
KW - Ultrasonic-assisted milling
KW - Residual stresses
KW - Cutting forces
KW - Surface integrity
KW - Microstructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524872
DO - https://doi.org/10.1007/s00170-021-06815-y
VL - 114
IS - 5-6
SP - 1427
EP - 1442
PB - Springer
AN - OPUS4-52487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Wandtke, Karsten
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Process-related influences and correlations in wire arc additive manufacturing of high-strength steels
N2 - High-strength fine-grained structural steels have great potential for weight-optimized, efficient structures in many modern steel applications. Further advances in efficiency can be achieved through additive manufacturing and bionic design. Commercial high-strength filler materials for wire arc additive manufacturing (WAAM) are already provided by the consumable producers. Today, application would be strictly limited due to absence of quantitative findings or any guidelines for the industry regarding welding-related stresses and component safety during manufacturing and service. Hence, process- and material-related influences and design-related restraint conditions associated with formation of residual stresses and cold cracking risk are investigated. The aim is the accessibility of special WAAM self-restraining cold cracking tests and easy applicable processing recommendations, enabling an economical, fit-for-purpose and crack-safe WAAM of high-strength steels. This first study focuses on determination of interactions between WAAM process parameters, resulting layer geometry, microstructure and residual stresses, analyzed via X-ray diffraction. Defined reference specimens are automated welded using a special WAAM solid wire (yield strength >820 MPa). Geometric properties can be specifically adjusted by wire feed and welding speed, but cannot be varied arbitrarily, since a high heat input causes local overheating, inadmissible changes of microstructure and mechanical properties, defects and comparable high tensile residual stresses.
T2 - 22. Werkstofftechnischen Kolloquium der TU Chemnitz
CY - Online meeting
DA - 24.03.2021
KW - Residual stresses
KW - Additive Manufacturing
KW - High-strength steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533300
DO - https://doi.org/10.1088/1757-899X/1147/1/012002
VL - 1147
SP - 012002
PB - IOP Publishing Ltd
AN - OPUS4-53330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Mente, Tobias
A1 - Richter, Tim
A1 - Kannengießer, Thomas
T1 - Characterization of Hydrogen Diffusion in Offshore Steel S420G2+M Multi-layer Submerged Arc Welded Joint
N2 - As onshore installation capacity is limited, the increase in the number of offshore wind turbines (OWT) is a major goal. In that connection, the OWTs continuously increase in size and weight and demand adequate foundations concepts like monopiles or tripods. These components are typically manufactured from welded mild steel plates with thickness up to 200 mm. The predominant welding technique is submerged arc welding (SAW). In accordance with the standards, the occurrence of hydrogen-assisted cracking is anticipated by either a minimum waiting time (MWT, before non-destructive testing of the welded joint is allowed) at ambient or a hydrogen removal heat treatment (HRHT) at elevated temperatures. The effectiveness of both can be estimated by calculation of the diffusion time, i.e., diffusion coefficients. In this study, these coefficients are obtained for the first time for a thick-walled S420G2+M offshore steel grade and its multi-layer SAW joint. The electrochemical permeation technique at ambient temperature is used for the determination of diffusion coefficients for both the base material and the weld metal. The coefficients are within a range of 1025 to 1024 mm2/s (whereas the weld metal had the lowest) and are used for an analytical and numerical calculation of the hydrogen diffusion and the related MWT. The results showed that long MWT can occur, which would be necessary to significantly decrease the hydrogen concentration. Weld metal diffusion coefficients at elevated temperatures were calculated from hydrogen desorption experiments by carrier gas hot extraction. They are within a range of 1023 mm2/s and used for the characterization of a HRHT dwell-time. The analytical calculation shows the same tendency of long necessary times also at elevated temperatures. That means the necessary time is strongly influenced by the considered plate thickness and the estimation of any MWT/HRHT via diffusion coefficients should be critically discussed.
T2 - European Congress and Exhibition on Advanced Materials and Process - Euromat 2021
CY - Online meeting
DA - 13.09.2021
KW - Thick-walled
KW - Hydrogen diffusion
KW - Offshore
KW - Steel
KW - Submerged arc welding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544127
DO - https://doi.org/10.1007/s11665-022-06679-7
SN - 1059-9495
SP - 1
EP - 13
PB - Springer Nature
AN - OPUS4-54412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
T1 - In situ investigation of chemical composition during TIG welding in duplex stainless steels using Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - Many applications in industry require a material-to-material joining process of Duplex Stainless Steels (DSS). Therefore, it is essential to investigate the material’s properties during a welding process to control the weld quality. With the help of Laser-Induced Breakdown Spectroscopy (LIBS), the chemical composition during the Tungsten Inert Gas (TIG) welding process of DSS could be monitored in situ. The chemical composition could be quantitatively measured using pre-established calibration curves. Although the surface temperature and the welding plasma have a high influence on the spectral intensities, reliable composition measurements were possible. The concentration of alloying elements could be mapped during the TIG welding process.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - LIBS
KW - In situ measurement
KW - WRC 1992 diagram
KW - TIG welding
KW - Duplex stainless steels
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542026
DO - https://doi.org/10.1016/j.finmec.2021.100063
SN - 2666-3597
VL - 6
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Steppan, Enrico
T1 - Zur Analyse der Eigenschaftsdegradation und des Bindungsverhaltens von Wasserstoff in höherfesten Feinkornbaustählen
N2 - Der Stahlbedarf in Deutschland wird maßgeblich neben dem Automobilsektor vom Maschinenbau und allgemeinen Bauwesen geprägt. In diesen Segmenten werden qualitativ hochwertige Stähle mit höchsten Ansprüchen an Festigkeit, Verformungsfähigkeit, schweißtechnische Verarbeitung und sicherheitsrelevante Aspekte gestellt. Wichtige Vertreter, welche diesen Ansprüchen gerecht werden, sind die heutigen modernen höherfesten FKB. Aus der Entwicklung dieser Stähle kristallisierten sich in den letzten Jahrzehnten verschiedene Legierungskonzepte und Herstellungsrouten heraus. Dem liegt neben essentiellen Eigenschaften, z.B. Streck- und Zugfestigkeit, noch weitere Anforderungen, bspw. Kaltumformbarkeit, Kerbschlagzähigkeit und Verschleißfestigkeit, zugrunde. Zunehmend werden im genormten Bereich mit Streckgrenzen bis 700 MPa neben den vergüteten Stählen (Q) auch thermomechanische Stähle (M) eingesetzt. Ein immerwährender paralleler Begleiter während der Stahlherstellung und -verarbeitung ist Wasserstoff.
Wasserstoff wird in den nächsten Jahren als Schlüsselelement für eine nachhaltige Energiewirtschaft angesehen. Aus heutiger Sicht ist Wasserstoff ein Hoffnungsträger für eine klimafreundliche Energiewirtschaft und zukunftsfähige Industrie. Forschung und Industrie arbeiten intensiv an der Erschließung und Weiterentwicklung des enormen Potentials, um eine höhere Nutzbarkeit zu erreichen. Die Gründe liegen zum einen darin, dass Wasserstoff als Brennstoff unproblematisch (Umweltverträglichkeit und Verfügbarkeit) ist und zum anderen ein hervorragender Energieträger ist.
Wasserstoff ist durch seine gebundene Form erst nach dem Lösen aus chemischen Verbindungen zugänglich. Dies geschieht für eine Nutzbarmachung in einer zukunftsfähigen Energiewirtschaft gezielt. Demgegenüber stehen Prozesse, wodurch Wasserstoff aus seiner chemischen Verbindung gelöst wird und aufgrund seiner Größe bzw. geringsten Atommasse von Werkstoffen aufgenommen wird. Damit verbunden interagiert der aufgenommene Wasserstoff mit dem Gefüge und kann zu einer negativen Beeinflussung der Eigenschaften des Werkstoffs führen.
Wasserstoff kann Degradationsprozesse in Stählen verursachen, die sich insbesondere auf die mechanischen Eigenschaften auswirken. Diese Mechanismen können wasserstoffunterstützte Risse in höherfesten Stählen während der Herstellung oder im industriellen Einsatz verursachen.
Elektrochemisch beladene Zugproben zeigen ein unterschiedliches Degradationsverhalten in ihren Eigenschaften. Die vorliegende Arbeit beschreibt die Wechselwirkungen zwischen Wasserstoff und Gitterdefekten in unterschiedlichen mikrolegierten Systemen und wärmebeeinflussten Zonen in den schweißbaren Feinkornbaustählen. Die Ergebnisse zeigen eine klare Abhängigkeit zwischen Mikrolegierung und Herstellungsprozess dieser Stahlsorten, respektive ihrer simulierten wärmebeeinflussten Bereiche.
N2 - In addition to the automotive sector, demand for steel in Germany is dominated by mechanical engineering and general construction. These segments demand high-quality steels with the highest requirements in terms of strength, formability, welding processing and safety aspects. Important representatives that meet these requirements are today's more modern high-strength FKB. In the development of these steels, various alloying concepts and production routes have crystallized in recent decades. In addition to essential properties, e.g. yield and tensile strength, this is also based on other requirements, e.g. cold formability, notched impact strength and wear resistance.
Increasingly, thermomechanical steels (M) are being used in addition to quenched and tempered steels (Q) in the standardized range with yield strengths up to 700 MPa. An ever-present parallel companion during steel production and processing is hydrogen.
Hydrogen is seen as a key element for a sustainable energy economy in the coming years. From today's perspective, hydrogen is a beacon of hope for a climate-friendly energy economy and sustainable industry. Research and industry are working intensively on tapping and further developing the enormous potential in order to achieve greater usability. The reasons are, on the one hand, that hydrogen is unproblematic as a fuel (environmental compatibility and availability) and, on the other hand, that it is an excellent energy carrier. Due to its bonded form, hydrogen is only accessible after dissolution from chemical compounds. This is done in a targeted manner for utilization in a sustainable energy economy. In contrast, there are processes by which hydrogen is released from its chemical compound and absorbed by materials due to its size or lowest atomic mass. In connection with this, the absorbed hydrogen interacts with the microstructure and can lead to a negative influence on the properties of the material.
Hydrogen can cause degradation processes in steels that affect mechanical properties in particular. These mechanisms can cause hydrogen-assisted cracking in higher strength steels during fabrication or in industrial use. Electrochemically loaded tensile specimens show different degradation behavior in their properties. The present work describes the interactions between hydrogen and lattice defects in different microalloyed systems and heat affected zones in the weldable fine grain structural steels. The results show a clear dependence between microalloying and manufacturing process of these steels, respectively their simulated heat affected zones.
T3 - BAM Dissertationsreihe - 172
KW - Höherfeste Feinkornbaustähle
KW - Wasserstoffdegradation
KW - Wasserstoffdiffusion
KW - Wasserstoffbindungsverhalten
KW - Kaltriss und Schweißen
KW - High strength fine grained structural steels
KW - Hydrogen degradation
KW - Hydrogen diffusion
KW - Hydrogen trapping
KW - Cold cracking and welding
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579412
SN - 1613-4249
VL - 172
SP - 1
EP - 266
PB - Eigenverlag
CY - Berlin
AN - OPUS4-57941
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Sprengel, Maximilian Franz-Arthur
T1 - Study on the determination and the assessment of the residual stress in laser powder bed fused stainless steel structures
N2 - Additive manufacturing processes offer extensive advantages for the design freedom of structures through layer-by-layer production. This enables high weight savings as well as the integration of functions such as cooling channels. This technology thus offers great potential to contribute to a sustainable future. The pioneer among these manufacturing processes is the powder bed fusion of metals with laser beams (PBF-LB/M). This process is characterised by high laser scanning speeds and highly localised heat input, which have a strong effect on the microstructure and thus also on the mechanical properties. For example, the austenitic steel 316L exhibits a cellular structure at the subgrain level. This microstructure feature leads to higher yield strengths and comparable ductility to conventionally processed 316L. In addition to the traditional applications of 316L steel in the petrochemical and nuclear industries, this enables new applications such as medical stents or bipolar plates for fuel cells with proton exchange membranes. However, the layer-by-layer production with high scanning speeds and localised heat input induces cooling rates in the order of 106 K.s-1. The large temperature gradients and the shrinkage restraints of each weld bead and layer lead to the development of complex residual stress fields. These reduce the material performance and can even lead to premature failure. Thus, the fatigue properties are severely affected by rapid crack growth or prematurely developing cracks. Furthermore, specimens may warp during PBF-LB/M or immediately when the components are separated from the build plate. Therefore, residual stress is one of the main disadvantages of PBF-LB/M, making it difficult for this technology to be more widely accepted in the industry. Based on the current state of the literature, the procedure for determining residual stress employing diffraction methods, the influence of the component geometry, as well as the inter-layertime (ILT) on residual stress and, lastly, suitable heat treatment strategies for relaxing residual stress in PBF-LB/M/316L, were identified as insufficiently researched areas.
Determining residual stress is a major challenge. X-ray and neutron diffraction are particularly suitable for filigree structures, which can preferably be produced using PBF-LB/M. Here, the microscopic strain of the lattice planes is used to calculate the macroscopic residual stress. These methods are nondestructive and allow the spatial resolution of the bi-axial and tri-axial residual stress. In the present work, in-situ neutron diffraction tensile tests were performed to analyse the micromechanical behaviour of PBF-LB/M/316L. The suitability of the lattice planes for calculating the macroscopic residual stress was investigated. The (311) lattice plane was found to be the best option for determining the macroscopic residual stress in PBF-LB/M/316L. Furthermore, it was shown that the Kröner model can be used to calculate the X-ray diffraction constants despite the texture. Currently, both aspects are common practices in the determination of residual stress. The results presented here support the validity of this approach and increase the confidence in the experimentally determined residual stress, which has a positive effect on the assessment of quality concerning the safety of a component manufactured by PBF-LB/M.
The geometry of a structure manufactured by PBF-LB/M determines the component stiffness and influences the thermal gradients during manufacture and ultimately the residual stress. The effect of smaller or larger dimensions (larger than 10 mm) on the residual stress is rarely considered. To investigate this aspect, representative test specimens with different thicknesses and lengths were produced. Hence, the influence of the geometry i.e., component stiffness on the residual stress was evaluated. The residual stress was determined using X-ray and neutron diffraction. The analysis of the residual stress showed that an increase in thickness leads to overall higher residual stress. In addition, it was shown that increasing the sample dimension leads to smaller residual stress gradients. Above a threshold value of a few millimetres, no significant change in the residual stress was observed.
The ILT is inherent in every PBF-LB/M construction job and influences the thermal gradients during production and thus the residual stress. A change in wall thickness in a geometrically complex structure or a variation in the number of specimens in the construction process leads directly to a change in the ILT. To simulate this, specimens with different ILT were produced. The residual stress was determined by X-ray and neutron diffraction. The use of a short ILT resulted in higher surface residual stress, but lower volume residual stress. Here, the surface residual stress and the residual stress in the volume showed contrary behaviour. This was attributed to the complex heat conduction during the process, as shown by the thermographic measurements.
To avoid distortion of the specimens or real components upon separation from the build plate or during post-processing steps, stress relief annealing is usually performed after the PBF-LB/M process. Based on standards for heat treatment of welded austenitic steels, heat treatments were performed at low (450 °C for four hours) and high (800 °C and 900 °C for one hour) temperatures. The results show that the heat treatment at 450 °C relaxed the residual stress by only 5 %. This low relaxation is due to the stability of the cell structures. The high-temperature heat treatment showed that 900 °C is required to dissolve the cell structure and achieve a relaxation of about 85 %. This result is in good agreement with the standards for stress relief annealing of welded austenitic steels.
N2 - Additive Fertigungsverfahren bieten durch die schichtweise Herstellung weitreichende Vorteile für die Gestaltungsfreiheit von Strukturen und ermöglichen somit hohe Gewichtseinsparungen. Auch die Integration von Funktionen, beispielsweise Kühlkanäle, können unmittelbar während der Herstellung eingebracht werden. Damit bietet diese Technologie ein hohes Potential zu einer nachhaltigen Zukunft beizutragen. Der Vorreiter unter diesen Fertigungsprozessen ist das Pulverbettbasierte Schmelzen von Metallen mittels Laserstrahlen (PBF-LB/M). Dieser Prozess zeichnet sich durch hohe Laserscangeschwindigkeiten und eine stark lokalisierte Wärmeeinbringung aus, welche sich auf die Mikrostruktur und damit auch auf die mechanischen Eigenschaften auswirken. So weist der austenitische Stahl 316L eine zelluläre Struktur auf Subkornniveau auf, welche zu höheren Streckgrenzen jedoch nicht verringerter Duktilität im Vergleich zu konventionell verarbeitetem 316L führt. Dies ermöglicht, neben den traditionellen Einsatzgebieten des Stahls 316L in der petrochemischen und nuklearen Industrie, neue Anwendungen wie medizinische Stents oder Bipolarplatten für Brennstoffzellen mit Protonenaustauschmembran. Die schichtweise Fertigung mit hohen Scangeschwindigkeiten und lokaler Wärmeeinbringung bedingt jedoch Abkühlraten in der Größenordnung von 106 K.s-1. Die hohen Temperaturgradienten im Zusammenspiel mit den Schrumpfbehinderungen jeder Schweißraupe und Lage sorgen für die Entstehung komplexer Eigenspannungsfelder. Diese verringern die Beanspruchbarkeit des Materials und können sogar zu einem vorläufigen Versagen führen. So sind die Ermüdungseigenschaften durch ein rapides Risswachstum bzw. ein vorzeitig entstehender Riss durch Eigenspannungen stark beeinträchtigt. Des Weiteren kommt es vor, dass sich die Proben während des PBF-LB/M oder unmittelbar bei der Trennung der Bauteile von der Bauplatte verziehen. Daher sind die Eigenspannungen eines der Hauptnachteile des PBF-LB/M, die eine breitere Akzeptanz dieses Verfahrens in der Industrie erschweren. Ausgehend vom aktuellen Literaturstand, wurde die Vorgehensweise bei der Bestimmung der Eigenspannungen mittels Beugungsmethoden, der Einfluss der Bauteilgeometrie bzw. Bauteilsteifigkeit sowie der Zwischenlagenzeit auf die Eigenspannungen und zuletzt geeignete Wärmebehandlungsstrategien zur Relaxation der Eigenspannungen in PBF-LB/M/316L als unzureichend erforschte Bereiche identifiziert.
Die Bestimmung der Eigenspannung ist eine große Herausforderung. Insbesondere bei filigranen Strukturen, welche vorzugsweise mittels PBF-LB/M hergestellt werden können, eignen sich die Röntgen- und Neutronenbeugung. Hierbei wird die mikroskopische Dehnung der Gitterebenen zur Berechnung der makroskopischen Eigenspannung verwendet. Diese Methoden sind zerstörungsfrei und ermöglichen die räumliche Auflösung der bi-axialen und tri-axialen Eigenspannungen. In der vorliegenden Arbeit wurden in-situ Neutronenbeugungszugversuche durchgeführt, um das mikromechanische Verhalten des PBF-LB/M/316L zu analysieren. Die Eignung der Gitterebenen zur Berechnung der makroskopischen Eigenspannung wurde untersucht. Die (311) Gitterebene erwies sich als die beste Option für die Bestimmung der makroskopischen Eigenspannung in PBF-LB/M/316L.
Darüber hinaus wurde gezeigt, dass das Kröner-Modell trotz Textur zur Berechnung der Röntgenbeugungskonstanten verwendet werden kann. Derzeit werden beide Aspekte in der Bestimmung der Eigenspannungen standardmäßig angewandt. Die hier präsentierten Ergebnisse untermauern die Gültigkeit dieses Vorgehens und erhöhen das Vertrauen in den experimentell bestimmten Eigenspannungen, welches sich positiv auf die Beurteilung der Qualität hinsichtlich der Sicherheit eines durch PBF-LB/M gefertigten Bauteils auswirkt.
Die Geometrie einer durch PBF-LB/M hergestellten Struktur bestimmt maßgeblich die Bauteilsteifigkeit und beeinflusst die thermischen Gradienten während der Herstellung und letztendlich die Eigenspannungen. Die Auswirkung kleinerer oder größerer Abmessungen (größer 10 mm) auf die Eigenspannungen wird derzeit oft nicht berücksichtigt. Um diesen Aspekt zu untersuchen, wurden repräsentative Probekörper mit unterschiedlichen Dicken und Längen hergestellt. Damit konnte der Einfluss der Geometrie bzw. Bauteilsteifigkeit auf die Eigenspannungen gezielt bewertet werden. Die Eigenspannungen wurden mittels Röntgen- als auch Neutronenbeugung bestimmt. Die Analyse der Eigenspannungen ergab, dass eine Erhöhung der Dicke zu insgesamt höheren Eigenspannungen führt. Zusätzlich wurde gezeigt, dass eine Vergrößerung der Probenabmessung zu kleineren Eigenspannungsgradienten führt. Oberhalb eines Schwellenwerts von wenigen Millimetern ändern sich die Eigenspannungen nicht mehr signifikant.
Die sogenannte Zwischenlagenzeit (ILT) ist jedem PBF-LB/M-Bauauftrag inhärent und beeinflusst die thermischen Gradienten während der Herstellung und damit maßgeblich die Eigenspannungen. Ein Wanddickensprung in einer geometrisch komplexen Struktur bzw. einer Variation der Probenanzahl im Bauprozess führt unmittelbar zu einer Änderung der ILT. Um dies nachzubilden, wurden Proben mit unterschiedlichen ILT hergestellt. Die Eigenspannungen wurden mittels Röntgen- und Neutronenbeugung bestimmt. Die Verwendung einer kurzen ILT hat zu höheren Oberflächeneigenspannungen geführt, jedoch zu geringeren Volumeneigenspannungen. Hierbei zeigten die Oberflächeneigenspannungen und die Eigenspannungen im Volumen ein konträres Verhalten. Dies wurde auf die komplexe Wärmeleitung während des Prozesses zurückgeführt, wie die thermografischen Messungen zeigten.
Um den Verzug der hergestellten Probekörper oder realen Bauteile bei der Abtrennung der Bauplatte oder in Nachbearbeitungsschritten zu vermeiden, wird in der Regel ein Spannungsarmglühen nach dem PBF-LB/M Prozess durchgeführt. Basierend auf Standards für die Wärmebehandlung von geschweißten austenitischen Stählen, wurden Wärmebehandlungen bei niedrigen (450 °C für vier Stunden) und hohen (800 °C bzw. 900 °C für eine Stunde) Temperaturen durchgeführt. Die Ergebnisse zeigen, dass die Wärmebehandlung bei 450 °C die Eigenspannungen um lediglich 5 % relaxierte. Diese geringe Relaxation ist auf die Stabilität der Zellstrukturen zurückzuführen. Die Hochtemperatur-Wärmebehandlung zeigte, dass 900 °C erforderlich sind, um die Zellstruktur aufzulösen und eine Relaxation von etwa 85 % zu erreichen. Dieses Ergebnis steht in guter Übereinstimmung mit den Standards für das Spannungsarmglühen geschweißter austenitischer Stähle.
T3 - BAM Dissertationsreihe - 173
KW - Residual Stress
KW - Powder Bed Fusion of Metals with Laser Beams
KW - Austenitic Stainless Steel
KW - Diffraction
KW - Heat Treatment
KW - Eigenspannungen
KW - Pulverbettbasiertes Laserstrahlschmelzen
KW - Austenitischer Rostfreier Stahl
KW - Beugung
KW - Wärmbehandlung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579802
SN - 1613-4249
VL - 173
SP - 1
EP - 256
PB - Eigenverlag
CY - Berlin
AN - OPUS4-57980
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Thomas, Maximilian
T1 - Verbesserung der Übertragbarkeit von Erstarrungsrissprüfungen nach dem MVT-Verfahren durch Digitalisierung der Probenauswertung
N2 - Zur Prüfung der Erstarrungsrissanfälligkeit von Werkstoffen existiert eine Vielzahl von Prüfverfahren, die jedoch oft nur in ihren Grundzügen standardisiert sind. Ein Beispiel ist der an der Bundesanstalt für Materialforschung und -prüfung entwickelte und angewendete Modifizierte Varestraint-/Transvarestraint-Test (MVT), der eine von vielen Umsetzungen des Varestraint-Verfahrensprinzips darstellt. Hierbei werden durch Biegung während des Schweißens gezielt Erstarrungsrisse erzeugt und anschließend lichtmikroskopisch vermessen. Die Ergebnisse von Varestraint-Prüfungen charakterisieren jedoch nicht allein das Werkstoffverhalten, sondern sind in hohem Maße von der Konstruktion der jeweiligen Prüfmaschine sowie den verwendeten Prüfparametern abhängig. Dies erschwert die Vergleichbarkeit von Ergebnissen, welche nicht unter exakt identischen Bedingungen ermittelt wurden, und kann darüber hinaus zu einer ungenauen oder unvollständigen Bewertung des Werkstoffverhaltens führen.
Die vorliegende Arbeit widmet sich zunächst der detaillierten Ausgestaltung der geometrischen Zusammenhänge rund um die Ausbreitung von Erstarrungsrissen während der Varestraint-Prüfung. Mit Blick auf Prokhorovs Technological Strength Theory und die sich daraus ergebenden erstarrungsrisskritischen Temperaturen wird anschließend eruiert, wie aus den Anfangs- und Endkoordinaten der entstandenen Risse auf das charakteristische Erstarrungsrissverhalten geschlossen werden kann. Die daraus entwickelte Bewertung der Rissanfälligkeit
ist weitestgehend von den Prüfparametern und weiteren verfahrensspezifischen Einflüssen entkoppelt, wodurch eine deutlich bessere Übertragbarkeit der Ergebnisse gewährleistet ist. Zur Erprobung der neu entwickelten Bewertungsansätze wurden zunächst MVT-Prüfungen an mehreren hochlegierten, martensitischen Schweißzusatzwerkstoffen, sowie am Nickelbasiswerkstoff Alloy 602 CA durchgeführt. So konnten einerseits verschiedene Legierungen hinsichtlich ihres Erstarrungsrissverhaltens charakterisiert und Empfehlungen für die schweißtechnische Fertigung generiert werden. Zum anderen dienten die Proben zur vollständigen Konzipierung, Entwicklung und Validierung einer digitalen Auswertemethodik.
Die eigens programmierte Software ermöglicht die schnelle und praxisgerechte Auswertung von MVT-Proben, und implementiert dabei zusätzlich die zuvor entwickelten, prozessunabhängigen Bewertungsansätze. Als Ergebnis konnten kritische Dehnraten identifiziert werden,ab deren Überschreitung die betrachteten Werkstoffe unter den verwendeten Prüfbedingungen gesteigerte Erstarrungsrissanfälligkeiten aufweisen. So ergibt sich ein direkter Zusammenhang zwischen MVT-Prüfergebnissen und der Technological Strength Theory
von Prokhorov. Die Bewertung des Werkstoffverhaltens anhand der kritischen Dehnraten erwies sich gegenüber den üblicherweise betrachteten Gesamtrisslängen als deutlich zuverlässiger.
Zusammenfassend konnte gezeigt werden, dass die digitale Auswertung eine sinnvolle Verbesserung der analogen Standardauswertung darstellt.
N2 - A multitude of testing procedures exist for the assessment of the solidification cracking susceptibilities of metal alloys. Many of these tests are only standardised on a very basic level.
This also applies to the Modified Varestraint-/Transvarestraint Test (MVT), which was developed at the Federal Institute for Materials Research and Testing (BAM) and is one of many variants of the original Varestraint test. Its functional principle is the bending of flat specimens during welding. Any solidification cracks formed during the procedure are quantified in a later step using optical light microscopy. However, the test results don’t exclusively characterise the analysed material, but also greatly depend on the design of the testing rig, as well as the applied testing parameters. This complicates the comparison of results obtained under different circumstances, and furthermore can lead to an inaccurate or insufficient assessment of the material characteristics.
The present work elaborates the geometrical aspects of solidification crack initiation and propagation during Varestraint testing. Applying Prokhorov’s Technological Strength Theory and the ensuing Brittleness Temperature Range, it is then determined how the start and end points of solidification cracks can be used to characterise the materials solidification cracking susceptibility. Ultimately, these insights are developed into a standard of evaluation which aims to eliminate the influence of testing parameters and characteristics, helping to greatly improve the comparability of Varestraint testing results.
To test the newly developed standard of evaluation, MVT tests were carried out on several high-alloyed martensitic steels, as well as on the nickel-based Alloy 602 CA. On the one hand, the obtained results provide detailed characterisations of the solidification cracking susceptibilities of different materials as well as guidelines for their use in welding processes.
On the other hand, the specimens were used for conception and validation of a novel, digital examination procedure. The software developed for this purpose allows for fast and practice-oriented examination of MVT specimens. At the same time, the new software implements the previously developed standard of evaluation to eliminate the influence of testing parameters. As a result, critical strain rates could be identified, which indicate the transition towards increased solidification cracking susceptibility under the respective circumstances.
In this way, a direct connection between MVT test results and Prokhorov’s Technological Strength Theory can be drawn. Compared to the Total Crack Length, which is usually given as a test result, critical strain rates were found to be a more reliable characteristic.
In summary, the newly developed procedures were proven to be a meaningful improvement of the current, analogue standard procedure.
T3 - BAM Dissertationsreihe - 171
KW - Heißriss
KW - Erstarrungsriss
KW - Schweißen
KW - Varestraint Test
KW - Digitalisierung
KW - Hot crack
KW - Solidification
KW - Welding
KW - Varestraint test
KW - digitalisation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553800
SN - 1613-4249
VL - 171
SP - 1
EP - 160
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-55380
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Hydrogen diffusion in thick-walled S690 SAW joints: Part 1 - Experimental determination of microstructure dependent diffusion coefficients
N2 - S690 steels are widely used in heavy-duty applications, such as structural components, mobile cranes, and industrial plant construction, owing to their high strength and weldability. However, thick-plate submerged arc welding (SAW) can introduce elevated hydrogen levels and residual stresses that promote time-delayed hydro-gen-assisted cold cracking (HACC). Accurate, microstructure-specific diffusion data are scarce, limiting pre-dictive HACC assessments. This study presents an experimental determination of hydrogen diffusion coeffi-cients (DH) in two S690 variants: thermomechanically rolled (S690MC) and quenched and tempered (S690Q). Multi-layer SAW welds were produced from 30 mm-thick plate material at three heat input levels, and diffusion membranes were extracted from weld metal (WM), heat-affected zone (HAZ), and base material (BM). Hydro-gen permeation tests, conducted in accordance with DIN EN ISO 17081, yielded time-normalized flux curves from which DH was derived using the inflection-point method. At room temperature, DH values ranged from 6 × 10⁻⁵ to 9 × 10⁻⁵ mm²/s across all regions and heat inputs, with no significant difference between S690MC and S690Q. Weld metal exhibited marginally lower DH, attributed to enhanced hydrogen trapping, while base mate-rial measurements showed greater variability. These microstructure-resolved diffusion coefficients fill a critical data gap and provide essential input for the numerical simulations presented in Part 2. The results also support practical guidelines for mitigating HACC risk through the optimization of welding parameters.
T2 - 78th IIW Annual Assembly, Meeting of Commission II-C
CY - Genoa, Italy
DA - 22.06.2025
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - High strength steels
KW - Hydrogen Diffusion
KW - Electrochemical permeation
PY - 2025
AN - OPUS4-63540
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Weld heat input effect on microstructure and hydrogen diffusion in thick-walled S690 submerged arc welded joints
N2 - High-strength, low-alloy (HLSA) steels such as S690 are an attractive option for heavy industries such as offshore wind turbines and peripheral equipment due to their combination of excellent mechanical properties and weldability. The construction of these thick-walled structures requires highly efficient welding processes such as submerged arc welding (SAW). However, SAW faces challenges related to delayed hydrogen assisted cold cracking (HACC). Despite its importance, the effect of different diffusion coefficients on the cold cracking susceptibility of different microstructures within SAW-welded S690 steels is not fully understood. For this reason, the present study focuses on comparing the cold cracking susceptibility of thermomechanically rolled (TM) or quenched and tempered (QL) variants of S690 steel. Submerged arc welding was performed on both steel grades at different welding heat inputs. From these thick-walled welds, metallic membranes were extracted from the weld metal, the heat-affected zone (HAZ), and the two base metals. The specimens were subjected to electrochemical hydrogen permeation tests (according to ISO 17081) to determine the microstructure-specific hydrogen diffusion coefficients. In general, increased welding heat input and thickness decreased the hydrogen diffusion coefficients, i.e., the time required for hydrogen diffusion increased. In addition, the results showed that the TM grade exhibited slightly accelerated hydrogen diffusion coefficients compared to the QL grade, which is beneficial for hydrogen reduction and increases the HACC resistance. As a result, the microstructure-specific assessment of hydrogen diffusion in the BM, HAZ or WM of the SAW joint was less important for a given set of welding parameters compared to other welding processes such as gas metal arc welding (GMAW). The reason is that in multilayer SAW, the relatively large welding heat input and multiple annealing resulted in similar microstructures, resulting in very close hydrogen diffusion coefficients. From this point of view, it is sufficient to characterize the hydrogen diffusion coefficients of both the weld metal and the base material.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genoa, Italy
DA - 26.06.2025
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - Diffusion
KW - Electrochemical permeation
KW - Microstructure
PY - 2025
AN - OPUS4-63543
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Hydrogen diffusion in thick-walled S690 SAW joints: Part 2 - Predictive modeling of welding heat input and microstructure influence
N2 - High-strength low-alloy (HSLA) steels such as S690 are widely employed in thick-walled welded structures, where hydrogen-assisted cold cracking (HACC) remains a persistent concern. While microstructure-specific hydrogen diffusion coefficients (DH) for weld metal (WM), heat-affected zone (HAZ), and base material (BM) were experimentally established in Part 1 of this study, their quantitative influence on hydrogen accumulation and effusion has not yet been fully clarified. This work presents a transient, spatially resolved numerical model for simulating hydrogen transport in multi-pass submerged arc welds. The model integrates experimentally determined DH values with realistic thermal cycles and temperature-dependent boundary conditions. Developed in Python, the simulation tool is purpose-built for hydrogen diffusion in welded joints and offers a focused, transparent alternative to general-purpose finite element platforms. Parametric analyses demonstrate that, although the diffusion coefficients vary by up to 50 %, their impact on overall hydrogen retention is minor. In contrast, welding parameters such as plate thickness, bead geometry, cooling time (t₈/₅), and interpass tem-perature exert a dominant influence on hydrogen distribution. Despite clear microstructural differences between the thermomechanically rolled (S690MC) and quenched and tempered (S690Q) variants, including hardness softening versus hardening in the heat-affected zone of the (pen)ultimate weld bead, the simulations confirm that their diffusion behavior and hydrogen solubility are closely aligned. Consequently, differences in diffusivity and solubility exert only a minor influence on hydrogen retention compared to thermal exposure and joint geometry. These findings support the interchangeable use of both steel grades in terms of HACC risk due to hydrogen diffusion kinetics, under comparable welding conditions.
T2 - 78th IIW Annual Assembly, Meeting of Commission II-C
CY - Genoa, Italy
DA - 22.06.2025
KW - Hydrogen assisted cracking
KW - Numerical simulation
KW - Hydrogen diffusion
PY - 2025
AN - OPUS4-63541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Czeskleba, Denis
A1 - Fleißner-Rieger, H.
A1 - Nietzke, Jonathan
A1 - Kannengießer, Thomas
T1 - Combined heating rate and restraint condition effect on stress relief cracking during PWHT of thick-walled Cr–Mo-V steel SAW joints
N2 - Creep-resistant steels such as 13CrMoV9-10 are utilized in the manufacture of thick-walled pressure vessels and are typically joined by submerged arc welding (SAW). However, these materials are susceptible to stress relief cracking (SRC) if the required post weld heat treatment (PWHT) is not applied correctly. Existing PWHT guidelines, encompassing heating rate and dwell (or holding) time at a given temperature, are derived from a synthesis of empirical knowledge and typically free-shrinkage weld experiments to assess the susceptibility to SRC. Therefore, this study discusses the combined effect of the PWHT heating rate under free-shrinkage compared to restrained shrinkage. Welding experiments were conducted (using plates with a thickness of 25 mm) for both shrinkage conditions for a variety of heating rates and maximum temperatures. In-situ acoustic emission analysis was used to locate propagating SRCs during PWHT. Hardness measurements, mechanical property characterization (Charpy impact strength), and microstructure correlation were used to evaluate the SRC susceptibility. The results suggested that the influence of heating rate could not be directly related to SRC formation and that the initial weld microstructure prior to PWHT was more relevant in terms of very high hardness in the coarse grain heat affected zone, especially that of the last beads in the top layer of the welding sequence. This was seen in the form of random, unexpected SRC occurrence in only one specimen at a heating rate commonly used in welding practice (approximately 100 K/h). In this context, the additional effect of an external shrinkage restraint on SRC must be considered in the form of increasing mechanical loads during welding, which are typically not within the scope of welding practice. To mitigate the probability of SRC during PWHT, it is imperative to reduce the welding heat input and to restrict the structural shrinkage restraint of the weld joint.
KW - Component test
KW - Stress relief cracking
KW - PWHT
KW - Creep-resistant steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631439
DO - https://doi.org/10.1007/s40194-025-02062-x
SN - 1878-6669
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-63143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Scharf-Wildenhain, R.
A1 - Schröpfer, Dirk
A1 - Hälsig, A.
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Influence of heat input on properties and residual stresses in hybrid addi-tive manufacturing of high strength steels using MSG processes
N2 - The application of steels with a higher yield strength allows reductions in wall thickness, component weight and production costs. Hybrid additive manufacturing based on Gas Metal Arc Welding (GMAW) processes (DED-Arc) can be used to realise highly effi-cient component modifications and repairs on semi-finished products and additively manufactured structures. There are still a number of key issues preventing widespread implementation, particularly for SMEs. In addition to the manufacturing design, detailed information about assembly strategy and geometric adaptation of the component for modifications or repairs are missing. These include the welding-related stresses associ-ated with the microstructural influences caused by the additive manufacturing steps, particularly in the transition area of the substrate and filler material interface. The pre-sent research focuses the effect of welding heat control during DED-Arc process on the residual stresses, especially in the transition area. Defined specimens were welded fully automatically with a high-strength solid wire (yield strength > 790 MPa) especially adapted for DED-Arc on S690QL substrate. The working temperature and heat input were systematically varied for a statistical effect analysis on the residual stress state of the hybrid manufactured components. Regarding heat control, t8/5 cooling times within the recommended processing range (approx. 5 s to 20 s) were complied. The investiga-tion revealed a significant influence of the working temperature Ti on the compressive residual stresses in the transition area and the tensile residual stresses at the base of the substrate. High working temperatures result in lower compressive residual stresses, heat input E does not significantly affect the tensile stresses.
T2 - 6. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632188
DO - https://doi.org/10.21268/20250506-3
SP - 110
EP - 122
AN - OPUS4-63218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Favres, Georges
T1 - European Metrology Network (EMN) for Advanced Manufacturing
N2 - The European Commission has identified Advanced Manufacturing and Advanced Materials as two of six Key Enabling Technologies (KETs). By fully utilizing these KETs, advanced and sustainable economies will be created. It is considered that Metrology is a key enabler for the advancement of these KETs. EURAMET, the association of metrology institutes in Europe, has strengthened the role of Metrology for these KETs by enabling the creation of a European Metrology Network for Advanced Manufacturing. The EMN is made up of National Metrology Institutes (NMIs) and Designated Institutes (DIs) from across Europe and was formally established in October 2021. The EMN aims to provide a high-level coordination of European metrology activities for the Advanced Materials and Advanced Manufacturing community.
The EMN itself is organized in three sections representing the major stages of the manufacturing chain: 1) Advanced Materials, 2) Smart Manufacturing Systems, and 3) Manufactured Components & Products. The EMN for Advanced Manufacturing is engaging with stakeholders in the field of Advanced Manufacturing and Advanced Materials (Large companies & SMEs, industry organisations, existing networks, and academia), as well as the wider metrology community (including TCs) to provide input for the preparation of a Strategic Research Agenda (SRA) for Metrology for Advanced Manufacturing.
This presentation will describe the progress in the development of the SRA by the EMN for Advanced Manufacturing. The metrology challenges identified across the various key industrial sectors, which utilise Advanced Materials and Advanced Manufacturing will be presented.
The EMN for Advanced Manufacturing is supported by the project JNP 19NET01 AdvManuNet.
T2 - 21st International Metrology Congress, CIM 2023
CY - Lyon (Chassieu), France
DA - 07.03.2023
KW - Advanced Materials
KW - EMN
KW - European Metrology Network for Advanced Manufacturing, Strategic Research Agenda
KW - SRA
PY - 2023
AN - OPUS4-59208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - O'Connor, Daniel
A1 - Evans, Alexander
A1 - Balsamo, Alessandro
A1 - Favres, Georges
A1 - Przyklenk, Anita
A1 - Bosse, Harald
A1 - Phillips, Dishi
T1 - European Metrology Network (EMN) for Advanced Manufacturing ─ Development of the Strategic Research Agenda (SRA)
N2 - The European Commission has identified Advanced Manufacturing and Advanced Materials as two of six Key Enabling Technologies (KETs). It is considered that Metrology is a key enabler for the advancement of these KETs. Consequently, EURAMET, the association of metrology institutes in Europe, has strengthened the role of Metrology for these KETs by enabling the creation of a European Metrology Network (EMN) for Advanced Manufacturing. The EMN is comprised of National Metrology Institutes (NMIs) and Designated Institutes (DIs) from across Europe and was formally established in October 2021. The aim of the EMN is to provide a high-level coordination of European metrology activities for the Advanced Manufacturing community.
The EMN itself is organized in three sections representing the major stages of the manufacturing chain: 1) Advanced Materials, 2) Smart Manufacturing Systems, and 3) Manufactured Components & Products. The EMN for Advanced Manufacturing is engaging with stakeholders in the field of Advanced Manufacturing (large companies & SMEs, industry organisations, existing networks, and academia), as well as the wider Metrology community, including Technical Committees, to provide input for the Strategic Research Agenda (SRA) on Metrology for Advanced Manufacturing.
This contribution will give an overview about the first version of the SRA prepared by the EMN for Advanced Manufacturing
T2 - Euspen, 23rd International Conference & Exhibitio
CY - Copenhagen, Danmark
DA - 12.06.2023
KW - European Metrology Network (EMN)
KW - Advanced Manufacturing
KW - Metrology
KW - Strategic Research Agenda (SRA)
PY - 2023
SP - 363
EP - 364
AN - OPUS4-59196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Constructing defect phase diagrams from ab initio calculations
N2 - Thermodynamic bulk phase diagrams have become the roadmap used by researchers to identify alloy compositions and process conditions that result in novel materials with tailored microstructures. On the other hand, recent progress in experimental atomic-scale characterization techniques allows one to study the local chemical composition at individual defects such as interfaces, grain boundaries, dislocations and surfaces. They show that changes in the alloy composition can drive not only transitions in the bulk phases present in a material, but also in the concentration and type of defects they contain. Defect phase diagrams, using chemical potentials as thermodynamics variables, provide a natural route to study these chemically driven defects. Our results show, however, that the direct application of thermodynamic approaches can fail to reproduce the experimentally observed defect formation.
Therefore, we extend the concept to metastable defect phase diagrams to account for kinetic limitations that prevent the system from reaching equilibrium. We use ab initio calculations based on density functional theory to quantify the extension of regions where defect formation is expected. We successfully applied this concept to explain the formation of large concentrations of planar defects in supersaturated Fe2Nb Laves phases. In addition, we identify in a joint study with experiments conditions and structures in Mg-Al-Ca alloys for defect phase occurrence. The concept offers new avenues for designing materials with tailored defect structures.
T2 - 6th MoD-PMI 2023 Workshop
CY - Aachen, Germany
DA - 29.05.2023
KW - Ab initio simulations
KW - Defects
KW - Phase diagrams
PY - 2023
AN - OPUS4-58854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ebell, Gino
T1 - Korrosion von Zink unter variierenden Bedingungen
N2 - Die Korrosionsbeständigkeit von zink in variierenden Elektrolyten hängt von der Deckschichtstabilität und Resistenz gegenüber dem Elektrolyten ab. Das amphotere Verhalten von Zinkhydroxid führt dazu das Zink in sauren und alkalischen Elektrolyten deutlich höhere Korrosionsraten erfährt als in pH-neutralen leicht alkalischen Elektrolyten. In diesem Vortrag werden verschiedene Anwendungsfälle dargestellt.
T2 - Gemeinschaftssitzung des AK atmosphärische Korrosion und Elektrotechnik
CY - Online meeting
DA - 05.12.2024
KW - Corrosion
KW - Korrosion
KW - Zink
PY - 2024
AN - OPUS4-62010
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulte, Petra
T1 - Physikalische Gefahren: Einstufungskriterien, Prüfmethoden, Vergleich mit Gefahrgutvorschriften
N2 - Vorgehensweise und Verfahren für die Validierung von Informationen zur Bewertung der Eigenschaften von Stoffen und Gemischen, die zu einer Einstufung und Kennzeichnung der physikalischen Gefahren nach der CLP-Verordnung (Verordnung (EG) Nr. 1272/2008) führen.
T2 - Haus der Technik e.V.: GHS/CLP Basisseminar - Einstufen und Kennzeichnen mit dem GHS (CLP-Verordnung)
CY - Wolfsburg, Germany
DA - 06.09.2022
KW - Einstufung
KW - Kennzeichnung
KW - GHS
KW - CLP
KW - Prüfmethoden
KW - Gefahrenklasse
KW - Gefahreneigenschaften
PY - 2022
AN - OPUS4-55589
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulte, Petra
T1 - Predicting explosive properties
N2 - This presentation focuses on the possibilities of the QSAR (Quantitative Structure-Activity Relationship) tools to access hazard properties using simulation techniques including the FAIR (Findable, Accessible, Interoperable, Reusable) data principles.
T2 - IGUS: Energetic and Oxidizing Substances Working Group (EOS)
CY - Stockholm, Sweden
DA - 20.09.2022
KW - QSAR Toolbox
KW - Explosive properties
KW - Energetic materials
KW - Friction sensitivity
KW - Impact sensitivity
KW - Thermal stability
PY - 2022
AN - OPUS4-56436
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulte, Petra
T1 - DSC measurements proficiency test
N2 - Differential Scanning Calorimetry (DSC) may be used to avoid testing for explosive and self-reactive properties according to the legal regulations of chemicals substances and dangerous goods.
Demonstrated measured exothermic decomposition energy value significantly affected by numerous factors - choice of sample vessel, sample mass, baseline shape, peak shape, heating rate.
T2 - IGUS: Energetic and Oxidizing Substances Working Group (EOS)
CY - Stockholm, Sweden
DA - 20.09.2022
KW - Dangerous Goods
KW - Classification
KW - DSC
KW - Exothermic decomposition energy
KW - Explosive properties
KW - Energetic materials
PY - 2022
AN - OPUS4-56437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulte, Petra
T1 - UN Test N.1 - Test method for flammable solids
N2 - This presentation focuses on the test procedure for assessing the flammability hazard for an appropriate classification according to GHS classification.
A comparison of test descriptions shows that the performance of the test should be improved so that a consistent evaluation would be achieved.
T2 - IGUS: Energetic and Oxidizing Substances working group (EOS)
CY - Stockholm, Sweden
DA - 20.09.2022
KW - Dangerous Goods
KW - Classification
KW - UN Test N.1
KW - Test methods
KW - Flammability
KW - GHS
PY - 2022
AN - OPUS4-56438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Breese, Philipp Peter
A1 - Metz, Christian
A1 - Altenburg, Simon
T1 - In-situ monitoring for PBF-LB/M processes: Does multispectral optical tomography add value in recognizing process deviations?
N2 - Laser powder bed fusion of metallic components (PBF-LB/M) is gaining acceptance in industry. However, the high costs and lengthy qualification processes required for printed components create the need for more effective in-situ monitoring and testing methods. This article proposes multispectral Optical Tomography (OT) as a new approach for monitoring the PBF-LB/M process. Compared to other methods, OT is a low-cost process monitoring method that uses long-time exposure imaging to observe the build process. However, it lacks time resolution compared to expensive thermographic sensor systems. Monochromatic OT (1C-OT) is already commercially available and observes the building process layer-wise using a single wavelength window in the NIR range. Multispectral OT (nC-OT) utilizes a similar setup but can measure multiple wavelength ranges per location simultaneously. By comparing the classical 1C-OT and nC-OT approaches, this article examines the advantages of nC-OT (two channel OT and RGB-OT) in reducing the false positive rate for process deviations and approximating maximum temperatures for a better comparison between different build processes and materials. This could ultimately reduce costs and time for part qualification. The main goal of this contribution is to assess the advantages of nC-OT compared to 1C-OT for in-situ process monitoring of PBF-LB/M.
T2 - Nolamp 2023
CY - Turku, Finland
DA - 22.08.2023
KW - Thermography
KW - Process Monitoring
KW - Additive manufacturing
KW - BPF-LB/M
KW - In-situ
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592498
DO - https://doi.org/10.1088/1757-899X/1296/1/012008
VL - 1296
SP - 1
EP - 11
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-59249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Scheuschner, Nils
A1 - Chand, Keerthana
A1 - Altenburg, Simon
A1 - Gerlach, G.
T1 - Potentials and challenges of deep-learning-assisted porosity prediction based on thermographic in-situ monitoring in laser powder bed fusion
N2 - Laser powder bed fusion is one of the most promising additive manufacturing techniques for printing complex-shaped metal components. However, the formation of subsurface porosity poses a significant risk to the service lifetime of the printed parts. In-situ monitoring offers the possibility to detect porosity already during manufacturing. Thereby, process feedback control or a manual process interruption to cut financial losses is enabled.
Short-wave infrared thermography can monitor the thermal history of manufactured parts which is closely connected to the probability of porosity formation. Artificial intelligence methods are increasingly used for porosity prediction from the obtained large amounts of complex monitoring data. In this study, we aim to identify the potential and the challenges of deep-learning-assisted porosity prediction based on thermographic in-situ monitoring.
Therefore, the porosity prediction task is studied in detail using an exemplary dataset from the manufacturing of two Haynes282 cuboid components. Our trained 1D convolutional neural network model shows high performance (R² score of 0.90) for the prediction of local porosity in discrete sub-volumes with dimensions of (700 x 700 x 40) μm³.
It could be demonstrated that the regressor correctly predicts layer-wise porosity changes but presumably has limited capability to predict differences in local porosity. Furthermore, there is a need to study the significance of the used thermogram feature inputs to streamline the model and to adjust the monitoring hardware. Moreover, we identified multiple sources of data uncertainty resulting from the in-situ monitoring setup, the registration with the ground truth X-ray-computed tomography data and the used pre-processing workflow that might influence the model’s performance detrimentally.
T2 - XXXVII. Messtechnisches Symposium 2023
CY - Freiburg, Germany
DA - 27.09.2023
KW - Porosity prediction
KW - Defect detection
KW - Laser powder bed fusion (PBF-LB/M, L-PBF)
KW - Selective laser melting
KW - Thermography
KW - Machine learning
PY - 2023
DO - https://doi.org/10.1515/teme-2023-0062
SN - 0171-8096
SN - 2196-7113
VL - 90
SP - 85
EP - 96
PB - De Gruyter
CY - Berlin
AN - OPUS4-58366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Altenburg, Simon
A1 - Scheuschner, Nils
A1 - Breese, Philipp Peter
A1 - Metz, C.
A1 - Hilgenberg, Kai
A1 - Maierhofer, Christiane
T1 - In-situ monitoring of the Laser Powder Bed Fusion build process via bi- chromatic optical tomography
N2 - As metal additive manufacturing (AM) is entering industrial serial production of safety relevant components, the need for reliable process qualification is growing continuously. Especially in strictly regulated industries, such as aviation, the use of AM is strongly dependent on ensuring consistent quality of components. Because of its numerous influencing factors, up to now, the metal AM process is not fully controllable. Today, expensive part qualification processes for each single component are common in industry.
This contribution focusses on bi-chromatic optical tomography as a new approach for AM in-situ quality control. In contrast to classical optical tomography, the emitted process radiation is monitored simultaneously with two temperature calibrated cameras at two separate wavelength bands. This approach allows one to estimate the local maximum temperatures during the manufacturing process, thus increases the comparability of monitoring data of different processes. A new process information level at low investment cost is reachable, compared to, e.g., infrared thermography.
T2 - LANE 2022
CY - Fürth, Germany
DA - 04.08.2022
KW - Optical tomography
KW - Additive Manufacturing
KW - L-PBF
KW - In-process monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560270
DO - https://doi.org/10.1016/j.procir.2022.08.035
SN - 2212-8271
VL - 111
SP - 340
EP - 344
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-56027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Oster, Simon
A1 - Metz, C.
A1 - Altenburg, Simon
T1 - In-situ defect detection via active laser thermographic testing for PBF-LB/M
N2 - Great complexity characterizes Additive Manufacturing (AM) of metallic components via laser powder bed fusion (PBF-LB/M). Due to this, defects in the printed components (like cracks and pores) are still common. Monitoring methods are commercially used, but the relationship between process data and defect formation is not well understood yet. Furthermore, defects and deformations might develop with a temporal delay to the laser energy input. The component’s actual quality is consequently only determinable after the finished process.
To overcome this drawback, thermographic in-situ testing is introduced. The defocused process laser is utilized for nondestructive testing performed layer by layer throughout the build process. The results of the defect detection via infrared cameras are shown for a research PBF-LB/M machine.
This creates the basis for a shift from in-situ monitoring towards in-situ testing during the AM process. Defects are detected immediately inside the process chamber, and the actual component quality is determined.
T2 - Lasers in Manufacturing (LiM)
CY - Munich, Germany
DA - 26.06.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Nondestructive testing
KW - Laser thermography
KW - Defect detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585060
SP - 1
EP - 10
PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik (WLT)
CY - Hannover
AN - OPUS4-58506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - In-situ Prüfung additiv gefertigter L-PBF-Bauteile mit aktiver Laserthermografie
N2 - Die additive Fertigung von metallischen Bauteilen (Additive Manufacturing - AM; auch 3D-Druck genannt) bietet eine Vielzahl an Vorteilen gegenüber konventionellen Fertigungsmethoden. Durch den schichtweisen Auftrag und das selektive Aufschmelzen von Metallpulver im Laser Powder Bed Fusion Prozess (L-PBF) sind u.a. optimierte und flexibel anpassbare Designs und die Nutzung von neuartigen Materialien möglich. Aufgrund der Komplexität des AM-Prozesses und der Menge an Einflussfaktoren ist eine Qualitätssicherung der gefertigten Bauteile unabdingbar. Verschiedene in-situ Monitoringansätze werden bereits angewendet, jedoch findet eine dedizierte Prüfung erst im Nachgang der Fertigung ex-situ statt. Der Grund dafür ist, dass die Entstehung von geometrischen Abweichungen und Defekten auch zeitversetzt zum eigentlichen Materialauftrag und damit auch zum Monitoring stattfinden kann. Die Notwendigkeit geeigneter in-situ Prüfmethoden für L-PBF, um die Erforderlichkeit einer Nacharbeitung frühzeitig festzustellen und Ausschuss zu vermeiden ist angesichts kostenintensiver Ausgangsstoffe und einer oftmals mehrstündigen bis mehrtägigen Prozessdauer besonders hoch.
Daraus motiviert wird im Rahmen des Projektes ATLAMP die Möglichkeit der aktiven Laserthermografie mit Hilfe des defokussierten Fertigungslasers untersucht. Damit ist, bei vergleichsweise geringer Laserleistung, eine zerstörungsfreie Prüfung mittels Flying Spot Thermografie möglich. Diese findet jeweils anschließend an die Fertigung einer Schicht statt, womit der reale Status des Bauteils im Verlauf des AM-Prozesses geprüft wird.
Als Grundlage dafür werden im Rahmen dieser Arbeit mit AM gefertigte, defektbehaftete Probekörper zunächst losgelöst vom Fertigungsprozess untersucht. Damit werden die Grundlagen für den neuartigen Ansatz der aktiven in-situ Laserthermografie im L-PBF-Prozess mittels des Fertigungslasers geschaffen. Auf diese Weise lassen sich auch zeitversetzt auftretende Defekte zerstörungsfrei im Prozessverlauf feststellen und eine aussagekräftige Qualitätssicherung des Ist-Zustands des Bauteils erreichen.
T2 - Thermographie-Kolloquium 2022
CY - Saarbrücken, Germany
DA - 28.09.2022
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Defekte
KW - Zerstörungsfreie Prüfung
KW - Aktive Laserthermografie
PY - 2022
UR - https://www.dgzfp.de/Portals/thermo2022/BB178/Inhalt/18.pdf
SN - 978-3-947971-27-5
AN - OPUS4-56810
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Potentials and challenges of deep-learning-assisted porosity prediction based on thermographic in-situ monitoring in PBF-LB/M
N2 - Laser powder bed fusion is one of the most promising additive manufacturing techniques for printing complex-shaped metal components. However, the formation of subsurface porosity poses a significant risk to the service lifetime of the printed parts. In-situ monitoring offers the possibility to detect porosity already during manufacturing. Thereby, process feedback control or a manual process interruption to cut financial losses is enabled.
Short-wave infrared thermography can monitor the thermal history of manufactured parts which is closely connected to the probability of porosity formation. Artificial intelligence methods are increasingly used for porosity prediction from the obtained large amounts of complex monitoring data. In this study, we aim to identify the potential and the challenges of deep-learning-assisted porosity prediction based on thermographic in-situ monitoring.
Therefore, the porosity prediction task is studied in detail using an exemplary dataset from the manufacturing of two Haynes282 cuboid components. Our trained 1D convolutional neural network model shows high performance (R2 score of 0.90) for the prediction of local porosity in discrete sub-volumes with dimensions of (700 x 700 x 40) μm³.
It could be demonstrated that the regressor correctly predicts layer-wise porosity changes but presumably has limited capability to predict differences in local porosity. Furthermore, there is a need to study the significance of the used thermogram feature inputs to streamline the model and to adjust the monitoring hardware. Moreover, we identified multiple sources of data uncertainty resulting from the in-situ monitoring setup, the registration with the ground truth X-ray-computed tomography data and the used pre-processing workflow that might influence the model’s performance detrimentally.
T2 - XXXVII. Messtechnisches Symposium 2023
CY - Freiburg im Breisgau, Germany
DA - 27.09.2023
KW - Porosity prediction
KW - Defect detection
KW - Laser Powder Bed Fusion (PBF-LB/M, L-PBF)
KW - Selective Laser Melting
KW - Thermography
KW - Machine Learning
PY - 2023
AN - OPUS4-59192
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Tina
T1 - Two approaches for multi measurand in-situ monitoring of the L-PBF process – bicolor- and RGB-optical tomography
N2 - Since metal additive manufacturing (AM) becomes more and more established in industry, also the cost pressure for AM components increases. One big cost factor is the quality control of the manufactured components. Reliable in-process monitoring systems are a promising route to lower scrap rates and enhance trust in the component and process quality.
The focus of this contribution is the presentation and comparison of two optical tomography based multi measurand in-situ monitoring approaches for the L-PBF process: the bicolor- and the RGB-optical tomography. The classical optical tomography (OT) is one of the most common commercial in-situ monitoring techniques in industrial L-PBF machines. In the OT spatial resolved layer-images of the L-PBF process are taken from an off-axis position in one near infrared wavelength window. In addition to the explanatory powers classical OT, both here presented approaches enable the determination of the maximum surface temperature. In contrast to thermography that may also yield maximum temperature information, the needed equipment is significantly cheaper and offers a higher spatial resolution. Both approaches are implemented at a new in-house developed L-PBF system (Sensor-based additive manufacturing machine - SAMMIE). SAMMIE is specifically designed for the development and characterization of in-situ monitoring systems and is introduced as well.
T2 - ICAM2022
CY - Orlando, FL, USA
DA - 31.10.2022
KW - Additive Manufacturing
KW - L-PBF
KW - In-process monitoring
KW - Optical tomography
PY - 2022
AN - OPUS4-56594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - In-situ defect detection for laser powder bed fusion with active laser thermography
N2 - Defects are still common in metal components built with Additive Manufacturing (AM). Process monitoring methods for laser powder bed fusion (PBF-LB/M) are used in industry, but relationships between monitoring data and defect formation are not fully understood yet. Additionally, defects and deformations may develop with a time delay to the laser energy input. Thus, currently, the component quality is only determinable after the finished process.
Here, active laser thermography, a non-destructive testing method, is adapted to PBF-LB/M, using the defocused process laser as heat source. The testing can be performed layer by layer throughout the manufacturing process. The results of the defect detection using infrared cameras are presented for a custom research PBF-LB/M machine. Our work enables a shift from post-process testing of components towards in-situ testing during the AM process. The actual component quality is evaluated in the process chamber and defects can be detected between layers.
T2 - 2023 Annual International Solid Freeform Fabrication Symposium
CY - Austin, TX, USA
DA - 14.08.2023
KW - Additive Manufacturing
KW - Additive Fertigung
KW - Laser Powder Bed Fusion
KW - Nondestructive Testing
KW - Flying Spot Laser Thermography
PY - 2023
AN - OPUS4-58137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - In-situ defect detection via active laser thermographic testing for PBF-LB/M
N2 - Great complexity characterizes Additive Manufacturing (AM) of metallic components via laser powder bed fusion (PBF-LB/M). Due to this, defects in the printed components (like cracks and pores) are still common. Monitoring methods are commercially used, but the relationship between process data and defect formation is not well understood yet. Furthermore, defects and deformations might develop with a temporal delay to the laser energy input. The component’s actual quality is consequently only determinable after the finished process.
To overcome this drawback, thermographic in-situ testing is introduced. The defocused process laser is utilized for nondestructive testing performed layer by layer throughout the build process. The results of the defect detection via infrared cameras are shown for a research PBF-LB/M machine.
This creates the basis for a shift from in-situ monitoring towards in-situ testing during the AM process. Defects are detected immediately inside the process chamber, and the actual component quality is determined.
T2 - Lasers in Manufacturing (LiM)
CY - Munich, Germany
DA - 26.06.2023
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Nondestructive Testing
KW - Defect Detection
KW - Flying Spot Laser Thermography
PY - 2023
AN - OPUS4-57922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Stark, T.
A1 - Arduini, M.
A1 - Manara, J.
A1 - Altenburg, Simon
T1 - Knowing the spectral directional emissivity of 316L and AlSi10Mg PBF-LB/M surfaces: Gamechanger for quantitative in situ monitoring
N2 - For a deep process understanding of the laser powder bed fusion process (PBF-LB/M), recording of the occurring surface temperatures is of utmost interest and would help to pave the way for reliable process monitoring and quality assurance. A notable number of approaches for in-process monitoring of the PBF-LB/M process focus on the monitoring of thermal process signatures. However, due to the elaborate calibration effort and the lack of knowledge about the occurring spectral directional emissivity, only a few approaches attempt to measure real temperatures. In this study, to gain initial insights into occurring in the PBF-LB/M process, measurements on PBF-LB/M specimens and metal powder specimens were performed for higher temperatures up to T = 1290 °C by means of the emissivity measurement apparatus (EMMA) of the Center for Applied Energy Research (CAE, Wuerzburg, Germany). Also, measurements at ambient temperatures were performed with a suitable measurement setup. Two different materials—stainless steel 316L and aluminum AlSi10Mg—were examined. The investigated wavelength λ ranges from the visible range (λ-VIS= 0.40–0.75 µm) up to the infrared, λ = 20 µm. The influence of the following factors were investigated: azimuth angle φ, specimen temperature TS, surface texture as for PBF-LB/M surfaces with different scan angles α, and powder surfaces with different layer thicknesses t.
T2 - Rapid.Tech 3D 2024
CY - Erfurt, Germany
DA - 14.05.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Emissivity
KW - Additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601471
DO - https://doi.org/10.1007/s40964-024-00665-2
SN - 2363-9520
SP - 1
EP - 10
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-60147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - Hyperspektrale Thermografie im metallischen Laser-Pulverbettschweißen (PBF-LB/M): Grundlagen für eine in-situ Realtemperatur-Bestimmung
N2 - Die additive Fertigung (Additive Manufacturing AM, auch als 3D Druck bekannt) von Metallen nimmt einen stetig wachsenden Stellenwert in industriellen Anwendungen ein. Gründe dafür sind u.a. die Möglichkeit der Umsetzung komplexer Bauteildesigns und die Nutzung neuartiger Werkstoffe. Damit hebt sich AM von konventionellen Fertigungsmethoden wie der subtraktiven Fertigung (Drehen, Fräsen, etc.) ab. Das für Metalle am weitesten verbreitete AM-Verfahren ist das Laser-Pulverbettschweißen (Laser Powder Bed Fusion PBF-LB/M, auch als Selective Laser Melting SLM bekannt). Es besitzt aktuell den höchsten Industrialisierungsgrad und die größte Anzahl an eingesetzten Maschinen. Bei PBF-LB/M liegt der metallische Ausgangswerkstoff unter Inertgasatmosphäre innerhalb einer Prozesskammer in einem Bett als Pulver vor und ein Laser schmilzt dieses lokal auf. Durch wiederholtes Auftragen einer neuen Pulverschicht und anschließendes selektives Schmelzen mit Hilfe des Lasers findet der lagenweise Aufbau eines Bauteils statt. Die dabei auftretenden lokalen Temperaturverteilungen bestimmen sowohl die Eigenschaften des gefertigten Bauteils als auch das mögliche Auftreten von Defekten wie Poren oder Risse. Durch diese Relevanz der thermischen Historie wäre die Aufzeichnung der auftretenden Realtemperaturen in zeitlicher und räumlicher Abhängigkeit optimal. Mit quantitativen Werten wären Vergleichbarkeit und Wiederholbarkeit des AM-Prozesses gegeben, was sich auch positiv auf Qualität und Sicherheit des gefertigten Bauteils auswirkt. Außerdem wäre ein Beitrag zur Validierung von Simulationen sowie zur Gewinnung eines tieferen Verständnisses des Fertigungsprozesses gegeben.
Jedoch findet aktuell lediglich ein qualitatives Monitoring statt (bspw. mittels Überwachung des Schweißbades durch eine Photodiode) und sicherheitsrelevante Bauteile müssen zeit- und kostenaufwändig im Nachgang ex-situ geprüft werden. Grund dafür sind auch die herausfordernden Bedingungen des PBF-LB/M-Prozesses mit hohen Scangeschwindigkeiten bei geringem Durchmesser des Laserspots. Des Weiteren erschweren die auftretenden Emissionsgradänderungen mit hoher Dynamik (zeitlich, räumlich) und den gegebenen Abhängigkeiten (temperatur-/wellenlängenabhängig) eine berührungslose Temperaturbestimmung basierend auf emittierter Infrarotstrahlung deutlich. Klassische Thermografie bietet zwar sehr gute qualitative Einblicke, ist dabei jedoch ohne eine aufwändige Temperaturkalibrierung inklusive Bildsegmentierung und Zuweisung von vorher ermittelten Emissionsgraden für eine verlässliche Bestimmung der Realtemperatur nicht ausreichend. Aus diesem Grund wird in dieser Veröffentlichung der Ansatz der hyperspektralen Thermografie für den PBF-LB/M Prozess vorgestellt: Die emittierte Infrarotstrahlung wird gleichzeitig bei einer Vielzahl von benachbarten Wellenlängenbereichen gemessen. Dies wird in dieser Untersuchung mittels einer selbst zusammengestellten hyperspektralen Linienkamera, die im kurzwelligen Infrarotbereich arbeitet, realisiert. Hierbei wird die thermische Strahlung einer Linie auf dem Messobjekt spektral aufgespalten und detektiert, sodass die spektrale spezifische Ausstrahlung entlang dieser Linie vermessen werden kann. Bewegt sich das Schmelzbad des PBF-LB/M Prozesses bei ausreichender Bildfrequenz durch diese Linie, ist eine räumliche Rekonstruktion eines effektiven Schmelzbades möglich.
Ein Ansatz, um aus diesen hyperspektralen Daten die gesuchten Emissionsgrade sowie die Realtemperatur zu ermitteln, sind Methoden der Temperatur-Emissionsgrad-Separation (TES). Ein Hauptproblem besteht darin, dass n spektrale Messungen verfügbar sind, jedoch n+1 Kenngrößen für jeden Bildpixel gesucht werden (n Emissionsgrade + eine Temperatur). TES-Methoden liefern die Möglichkeit, dieses mathematisch unterbestimmte Problem verlässlich und nachvollziehbar zu approximieren, indem der spektrale Emissionsgrad mit wenigen Freiheitsgraden analytisch parametriert wird. Mit Hilfe dieses Ansatzes werden Setup und Methoden an SAMMIE (Sensor-based Additive Manufacturing Machine), einer Forschungsmaschine für PBF-LB/M, angewendet. Erste Ergebnisse unter AM-Prozessbedingungen werden gezeigt, welche die Grundlage für die Bestimmung von Realtemperaturen im PBF-LB/M-Prozess bilden. Dies leistet einen wichtigen Beitrag zur verbesserten Vergleichbarkeit und Wiederholbarkeit der Fertigung, zur Validierung von Simulationen sowie zum Verständnis des Prozesses selbst. Das unterstützt langfristig dabei das Vertrauen in die Sicherheit von AM-Produkten zu stärken.
T2 - TEMPERATUR 2024
CY - Berlin, Germany
DA - 05.06.2024
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Schmelzbadtemperatur
KW - Hyperspectral Imaging
KW - Emissionsgrad
KW - Quantitative Temperatur
PY - 2024
AN - OPUS4-60753
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - SAMMIE – PBF-LB/M Research System for the Development of in-situ Monitoring methods
N2 - The additive manufacturing of metals has now reached a level of maturity that enables its use in many branches of industry or brings it within reach. The main advantages are the ability to produce complex components that cannot be produced conventionally or only at great expense, as well as in the production of highly individualized components in small quantities. However, the additive manufacturing process is highly complex and prone to errors. In order to guarantee the quality control required particularly for safety-relevant components, complex downstream nondestructive testing NDT of the individual components is currently necessary. In-situ process monitoring and testing could offer alternatives, but these have not yet reached a sufficient level of functionality. Industrial production facilities offer little or no flexibility and accessibility to enable extensive investigations in this area. For this reason, we developed a system for the powder bed fusion process of metals (PBF-LB/M) called SAMMIE. It offers a completely open system architecture with full control over the process and flexible access to the build chamber, e.g., optically both on-axis and off-axis to the production laser. In this contribution, we present the system and show first experimental results of in-situ monitoring and testing, e.g., high-resolution thermographic melt pool monitoring, multispectral optical tomography, and high-speed videos of the process. SAMMIE enables us to conduct fundamental investigations that will help to further develop in-situ process monitoring and testing, gain new insights into the process, and improve its safety and reliability.
T2 - 48th MPA-Seminar
CY - Stuttgart, Germany
DA - 08.10.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Custom machine
KW - Additive Manufacturing
KW - Process monitoring
PY - 2024
AN - OPUS4-61350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Tina
T1 - PBF-LB/M: Prozess Monitoring mittels Multispektraler OT
N2 - Die metallische additive Fertigung hat in den letzten Jahren in der industriellen Fertigung zunehmend an Bedeutung gewonnen. Hierbei dominiert das Laser-Pulverbettschweißen von Metallen (PBF/LB-M) die Fertigung von kleinformatigen Bauteilen mit hoher Oberflächengüte. Die anspruchsvolle und kostspielige Qualitätssicherung stellt aber weiterhin ein Hindernis für eine breitere und kostengünstigere Anwendung der additiven Fertigung dar. Dies resultiert teilweise aus fehlenden zuverlässigen In-situ-Monitoringsystemen. Belastbarere Prozessüberwachungsdaten würden eine oft erforderliche teure nachgelagerte Prüfung mittels Computertomografie entbehrlich machen. Die Aufzeichnung der thermischen Signaturen des Aufbauprozess mittels Thermografie-Kameras zeigen hier vielversprechende Ergebnisse. Eine Korrelation zu auftretender Porosität, Delaminationen und Deformationen scheinen möglich. Die geringe räumliche Auflösung und die hohen Anschaffungskosten für thermografische Kamerasysteme stehen jedoch einer größeren industriellen Nutzung im Wege.
Ein bereits industriell angewendeter Ansatz zur in-Situ Überwachung des PBF-LB/M Prozesses ist die Optische Tomografie (OT). Hierbei wird die emittierte Prozessstrahlung jeder Bauteilschicht mittels einer hochauflösenden günstigen Kamera für den sichtbaren Wellenlängenbereich in einer Langzeitbelichtung dokumentiert. Die zeitliche Information der emittierten Strahlung geht hierbei verloren. Der gesamte Bauprozess kann jedoch in einem vergleichsweise kleinen Datensatz dokumentiert werden (ein Bild pro Schicht). Eine direkte Korrelation zu auftretenden Defekten gestaltet sich aufgrund der reduzierten thermischen Informationsdichte jedoch schwierig.
In diesem Beitrag soll deshalb das Prinzip der Multispektralen Optischen Tomografie (MOT) vorgestellt und erste Messergebnisse an der Forschungsanlage SAMMIE diskutiert werden. Bei der MOT handelt es sich um eine Übertragung des Prinzips der Quotientenpyrometrie auf das etablierte Verfahren der Optischen Tomografie. Die auftretende Prozessstrahlung wird in mehreren Wellenlängenbereichen ortsaufgelöst über die gesamte Bauplattform erfasst und zeitlich in einer Langzeitbelichtung integriert. Hierbei kommen günstige Kamerasysteme für den sichtbaren Wellenlängenbereich zum Einsatz.
Das erfasste Signal I jedes Bildpixels für jeden separat erfassten Wellenlängenbereich kann als Maß für das zeitliche Integral der spezifischen Ausstrahlung M des Schmelzbades in diesem Wellenlängenbereich gesehen werden. Nach dem Stefan-Boltzmann-Gesetz hängt die abgestrahlte thermische Leistung P eines idealen Schwarzen Körpers in der vierten Potenz von dessen absoluten Temperatur T ab. Wird nur, wie z.B. bei der klassischen OT angewendet, der nahinfrarote Wellenlängenbereich betrachtet, lässt sich mit dem Planck’schen Strahlungsgesetz sogar eine Proportionalität zur siebten Potenz der Temperatur zeigen. Deshalb liegt ein starker Einfluss der maximal auftretenden Oberflächentemperatur Tmax auf das erfasste Messsignal vor.
Das erfasste Signal I wird aber auch durch die spektrale Transmission τ der verwendeten optischen Komponenten des Kamera-Setups, z.B. Filter und Objektive, durch die spektrale Sensitivität S der verwendeten Kamera-Sensoren und den nur sehr schwer zu bestimmenden Emissionsgrad ε der emittierenden (flüssigen) Oberfläche beeinflusst.
In einer ersten Näherung wird das Schmelzbad hier als Graukörper, also ein Körper mit wellenlängenunabhängigem Emissionsgrad ε, betrachtet. Basierend auf dieser Annahme und vermessenen optischen Eigenschaften des verwendeten Systems ist es möglich, eine erste Schätzung der maximalen Oberflächentemperatur Tmax vorzunehmen, selbst ohne genaue Kenntnis des tatsächlichen Emissionsgrades ε. Dies wird durch die Anwendung des Planck‘schen Strahlungsgesetzes und die Quotienten Bildung aus den einzelnen erfassten Signalen I ermöglicht.
Auch bei diesem Verfahren geht die zeitliche Information einer Schicht, also das Aufwärm- und Abkühlverhalten des Schmelzbades, verloren. Zudem sind die Messergebnisse in Hinblick auf tatsächlich gemessene „maximal auftretende Oberflächentemperatur“ mit gebotener Zurückhaltung zu interpretieren. Trotzdem konnten erste Ergebnisse bereits zeigen, dass die MOT-Daten auch in Bereichen mit Doppelbelichtungen (das teilweise notwendige mehrfache Scannen eines Bereiches mittels des Fertigungslasers) im Gegensatz zur klassischen OT erwartbare Maximaltemperaturen liefern. Abbildung 1 zeigt das erfasste Messergebnis für drei aufeinanderfolgende Schichten eines Bauteils einmal mit MOT (links) und einmal mit einfacher OT (rechts). Deutlich zu erkennen ist das durch die doppelte Belichtung hohe Signal bei der OT. Die Daten der MOT zeigen hier keine erhöhten Werte.
Um die ermittelten Temperaturwerte mittels MOT besser einordnen zu können, sind u.a. vergleichende Messungen an Referenzmaterialien geplant. Um die Auswertung der gemessenen Daten zu verbessern, wird zudem der Zeitverlauf des Abkühlens und Aufheizens des Schmelzbades sowie die Einflüsse von Prozessbeiprodukten wie Schmauch und Spritzer näher untersucht. Auch werden Messungen zum Emissionsgrad ε an additiv gefertigten Proben und Metallschmelzen vorgenommen.
T2 - Temperatur 2024
CY - Berlin, Germany
DA - 05.06.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Optische Tomografie
KW - Additive Fertigung
KW - Prozessüberwachung
KW - Additive Manufacturing
PY - 2024
AN - OPUS4-60235
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Prozessüberwachung mittels Thermografie im Laser-Pulverbettschweißen zur Vorhersage von Fehlstellen im Bauteilvolumen
N2 - Metallbasierte additive Fertigungsverfahren werden zunehmend industriell zur Anfertigung von komplex geformten Komponenten eingesetzt. In diesem Zusammenhang ist das Laser-Pulverbettschweißen von Metall (PBF-LB/M) ist ein weitläufig genutztes Verfahren. Im PBF-LB/M-Prozess werden lagenweise aufgetragene Metallpulverschichten selektiv mittels eines Lasers aufgeschmolzen. Die Entstehung von internen Fehlstellen (bspw. Porosität, Lunker oder Risse) während des Fertigungsvorgangs stellt ein ernstzunehmendes Risiko für die Bauteilsicherheit und somit für die weitere industrielle Etablierung des Verfahrens dar. Die Entstehung von Fehlstellen hängt eng mit lokalen Änderungen der thermischen Historie des Bauteils zusammen. Mit Hilfe von thermografischen Kameras zur Prozessüberwachung kann die thermische Historie bereits während der Fertigung erfasst werden. Damit eröffnet sich die Möglichkeit, die Entstehung von Fehlstellen anhand der thermografischen Daten vorherzusagen und somit potenziell Kosten für eine nachgelagerte Qualitätssicherung einzusparen.
In diesem Beitrag soll die Modellierung der Fehlstellenvorhersage anhand thermografischer Prozessdaten diskutiert werden. Hierbei liegt ein Schwerpunkt auf der Fragestellung, mit welcher Genauigkeit unterschiedliche Formen von Fehlstellen, im speziellen Anbindungsfehler und Keyhole-Porosität, auf lokaler Bauteilebene vorhergesagt werden können. Weiterhin werden verschiedenen Modelltypen aus dem Bereich des Maschinellen Lernens auf ihre Eignung für die Fehlstellenvorhersage verglichen. Ein weiterer zentraler Aspekt in diesem Zusammenhang ist die Untersuchung der Eingangsdaten des Modells auf ihre Relevanz für das Vorhersageergebnis.
Als Datengrundlage für die durchgeführten Untersuchungen dienen die Fertigungsprozesse von zwei identischen Haynes-282-Bauteilen (Nickel-Basislegierung), welche mit Hilfe einer im kurzwelligen Infrarotbereich arbeitenden Thermografiekamera überwacht wurden. Das Bauteildesign umfasste lokale Bereiche, in denen mit Hilfe einer Parametervariation die Entstehung von Fehlstellen forciert wurde. Um die Position und Größe der entstandenen Defekte zu quantifizieren, wurden beide Bauteile nach erfolgter Fertigung mittels Computertomografie (CT) geprüft. Im Rahmen der Datenvorbereitung für die Modellierung erfolgte eine Reduzierung der erhobenen Thermogramme zu physikalisch-interpretierbaren Merkmalen (bspw. Schmelzbadfläche oder Zeit-über-Schwellwert). Weiterhin erfolgte eine Registrierung der thermografischen Daten mit den Fehlstellen-Referenzdaten der CT, um eine exakte örtliche Überlagerung von thermischer Information und lokalem Fehlstellenbild zu erzielen. Zur Ermöglichung einer lokalen Fehlstellenvorhersage wurden die thermografischen Daten schichtweise in kleinteiligen Volumina angeordnet, welche als Eingangsgröße für die genutzten ML-Algorithmen dienten.
Die Ergebnisse der Untersuchungen zeigen, dass sich die Porosität auf Bauteilschichtebene mit einer hohen Genauigkeit vorhersagen lässt. Eine Vorhersage der Porosität auf lokaler Bauteilebene erweist sich noch als herausfordernd. Die erprobten ML-Algorithmen zeigen vergleichbare Ergebnisse, obwohl ihnen unterschiedliche Modellierungsannahmen zugrunde liegen und sie variierende Komplexität aufweisen. Mit Hilfe der erzielten Erkenntnisse eröffnet sich die Möglichkeit, Rückschlüsse auf die gewählte Prozessüberwachungshardware und Datenvorverarbeitung zu ziehen und somit langfristig die Leistungsfähigkeit von Modellen zur Fehlstellenvorhersage zu verbessern.
T2 - Temperatur 2024
CY - Berlin, Germany
DA - 05.06.2024
KW - Laser-Pulverbettschweißen
KW - Porositätsvorhersage
KW - Qualitätsüberwachung
KW - Thermografie
KW - Machine Learning
PY - 2024
AN - OPUS4-60267
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - SAMMIE: Eigenbau-Anlage für Metall-AM zur Sensorentwicklung und Qualifizierung
N2 - Im additiven Fertigungsprozess Laser-Pulverbettschweißen wird Metallpulver lagenweise mittels eines Lasers aufgeschmolzen, um Bauteile zu generieren. Hierbei werden die Eigenschaften der Bauteile zu einem großen Teil durch die im Verlauf des Prozesses vorliegenden Temperaturen bestimmt. Dies beinhaltet unter anderem Materialeigenschaften wie Mikrostruktur, Härte, thermische und elektrische Leitfähigkeiten sowie die Ausbildung von Defekten wie z.B. Anbindungsfehler, Keyhole-Porosität (Gaseinschlüsse) oder auch die Ausbildung von Rissen. Zur Überwachung bzw. Vorhersage dieser Eigenschaften sowie zum Abgleich von Simulationen ist eine orts- und zeitaufgelöste Messung der Temperaturverteilung im Prozess daher von herausragender Bedeutung. In der Industrie kommen optische Verfahren, die auf der Messung der thermischen Strahlung basieren, regelmäßig zum Einsatz. Allerdings dienen diese bislang nur der statistischen Auswertung und der Identifikation von Abweichungen vom Normalprozess. Der quantitativen Auswertung zur Temperaturbestimmung stehen aktuell noch eine Vielzahl von Herausforderungen entgegen. Einerseits stellt der Prozess an sich hohe Anforderungen an die Datenerfassung und -auswertung: der Emissionsgrad verändert sich dynamisch im Prozess und lokale Schmauchbildung sorgt für potenzielle Absorption oder Streuung der thermischen Strahlung oder auch des Fertigungslasers. Weiterhin stellt der hochdynamische Prozess hohe Anforderungen an Orts- und Zeitauflösung der eingesetzten Sensorik (z.B. Kameratechnik). Andererseits erschweren an üblichen kommerziell erhältlichen Fertigungsanlagen praktische Hindernisse wie eine eingeschränkte optische Zugänglichkeit und der fehlende Zugriff auf die Anlagensteuerung sowie fehlende Möglichkeiten der Synchronisation der Messtechnik mit dem Prozess eine eingehende Untersuchung dieser Effekte.
Um letztere Hindernisse zu umgehen, wurde an der BAM die Forschungsanlage SAMMIE (sensor-based additive manufacturing machine) entwickelt. Einerseits bietet das System alle Möglichkeiten, die auch übliche kommerzielle Systeme bieten. Dies beinhaltet die Fertigung ganzer Bauteile (maximale Größe ca. 65mm x 45 mm x 30 mm) und den Einsatz einer Inertgasatmosphäre inkl. gefiltertem Schutzgasstrom. Andererseits bietet es aber auch einen besonders kompakten Bauraum, um die Sensorik möglichst nah an den Prozess führen zu können, sechs optische Fenster zur Prozessbeobachtung aus unterschiedlichen Winkeln und die Möglichkeit der Prozessbeobachtung koaxial zum Fertigungslaser. Des Weiteren besteht eine einfache Austauschbarkeit aller Fenster, Spiegel und Strahlteiler, um den gesamten optischen Pfad der aktuellen Messaufgabe flexibel anzupassen. Die komplette Anlagensteuerung ist eine Eigenentwicklung und bietet daher auch völlige Anpassbarkeit. Eine synchrone und frei konfigurierbare Triggerung diverser Sensoriken und synchrone Datenerfassung bieten maximale Kontrolle über die Sensorsteuerung.
Dieser Beitrag gibt einen Überblick über die Fertigungsanlage SAMMIE. Wissenschaftliche Ergebnisse sowie laufende Arbeiten an der Anlage werden in weiteren Beiträgen vorgestellt.
T2 - Temperatur 2024
CY - Berlin, Germany
DA - 05.06.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Anlage
KW - Additive Fertigung
KW - Prozessüberwachung
KW - Additive Manufacturing
PY - 2024
AN - OPUS4-60234
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Machine Learning based defect detection in Laser Powder Bed Fusion utilizing thermographic feature data
N2 - The formation of irregularities such as keyhole porosity pose a major challenge to the manufacturing of metal parts by laser powder bed fusion (PBF-LB/M). In-situ thermography as a process monitoring technique shows promising potential in this manner since it is able to extract the thermal history of the part which is closely related to the formation of irregularities. In this study, we investigate the utilization of machine learning algorithms to detect keyhole porosity on the base of thermographic features. Here, as a referential technique, x-ray micro computed tomography is utilized to determine the part's porosity. An enhanced preprocessing workflow inspired by the physics of the keyhole irregularity formation is presented in combination with a customized model architecture. Furthermore, experiments were performed to clarify the role of important parameters of the preprocessing workflow for the task of defect detection . Based on the results, future demands on irregularity prediction in PBF-LB/M are derived.
T2 - International Conference on NDE 4.0
CY - Berlin, Germany
DA - 24.10.2022
KW - Laser Powder Bed Fusion
KW - Thermography
KW - In-situ Monitoring
KW - Convolutional Neural Networks
PY - 2022
AN - OPUS4-56332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Tina
T1 - Emissivity – Gamechanger for quantitative in-situ monitoring
N2 - For a deep process understanding of the laser powder bed fusion process (PBF-LB/M), recording of the occurring surface temperatures is of utmost interest and would help to pave the way for reliable process monitoring and quality assurance. A notable number of approaches for in-process monitoring of the PBF-LB/M process focus on the monitoring of thermal process signatures. However, due to the elaborate calibration effort and the lack of knowledge about the occurring spectral directional emissivity, only a few approaches attempt to measure real temperatures. In this study, to gain initial insights into occurring in the PBF-LB/M process, measurements on PBF-LB/M specimens and metal powder specimens were performed for higher temperatures up to T = 1290 °C by means of the emissivity measurement apparatus (EMMA) of the Center for Applied Energy Research (CAE, Wuerzburg, Germany). Also, measurements at ambient temperatures were performed with a suitable measurement setup. Two different materials—stainless steel 316L and aluminum AlSi10Mg—were examined. The investigated wavelength λ ranges from the visible range (λ-VIS = 0.40–0.75 µm) up to the infrared, λ = 20 µm. The influence of the following factors were investigated: azimuth angle φ, specimen temperature TS, surface texture as for PBF-LB/M surfaces with different scan angles α, and powder surfaces with different layer thicknesses t.
T2 - Rapid.Tech 3D 2024
CY - Erfurt, Germany
DA - 14.05.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Emissivity
KW - Additive Manufacturing
PY - 2024
AN - OPUS4-60148
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilberg, Alec
T1 - In-situ Temperaturbestimmung im LPA Prozess mittels multispektraler Thermografie
N2 - Mit der zunehmenden Relevanz der additiven Fertigung in Fertigungsbereiche mit hohen Anforderungen an Bauteilqualität, wird eine gute Prozessüberwachung unausweichlich. Eine Methode, die bereits gute Korrelation mit Bauteilfehlern gezeigt hat, ist die Temperaturüberwachung mithilfe von thermografischen Methoden. Allerdings unterliegt die Bestimmung der Realtemperaturen vielen unterschiedlichen Problemen. Ein Ansatz mit den Herausforderungen umzugehen, stellt der multispektrale Ansatz dar, der im Projekt QT-LPA untersucht und hier vorgestellt wird.
T2 - Temperatur 2024
CY - Berlin, Germany
DA - 05.06.2024
KW - Additive Fertigung
KW - Multispektral Thermografie
KW - LPA
PY - 2024
AN - OPUS4-60921
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breese, Philipp Peter
A1 - Altenburg, Simon
T1 - Absolute temperature determination in laser powder bed fusion (PBF-LB/M) via hyperspectral thermography
N2 - Temperature is a key characteristic in laser powder bed fusion of metals (PBF-LB/M). As a quantitative physical property, the temperature can determine the actual process quality independently from the nominal process parameters. Thus, establishing a process evaluation on temperatures rather than the comparison of process conditions is expected to be more effective. However, quantitative in situ temperature measurements with classical thermographic methods are virtually impossible. The reason is that the required emissivity value changes drastically throughout the process. Additionally, large temperature ranges along with the highly dynamic nature of the PBF-LB/M process make temperature measurements difficult. Based on this challenge, this work presents a method for hyperspectral temperature determination. The spectral exitance (in W/m2⋅nm) was measured in situ at many adjacent wavelengths in the short-wave infrared (SWIR). This enabled a local temperature determination via Planck’s law in combination with a spectral emissivity function. The temperature field of the melt pool crossing the 1D measurement line was reconstructed from the information, gathered at nearly 20 kHz sampling rate. The reconstructed melt pool had a spatial resolution of 17 µm by 40 µm, and temperatures between 2700 and 1300 K were observable. Comparison of the 316L stainless steel solidification temperature and the observed solidification plateau in the gathered thermal data revealed a relative error of less than 6% in the absolute temperature measurement. These initial results of hyperspectral temperature determination in PBF-LB/M show the potential in the method. It allows for physically founded process evaluation, and the prospects for tuning and validation of numerical simulations are highly promising.
KW - Additive Manufacturing
KW - Infrared Thermography
KW - In-situ Monitoring
KW - Quantitative Temperature Measurement
KW - Emissivity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631977
DO - https://doi.org/10.1007/s40964-025-01148-8
SN - 2363-9512
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-63197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Oster, Simon
A1 - Metz, C.
A1 - Altenburg, Simon
T1 - In-situ defect detection for laser powder bed fusion with active laser thermography
N2 - Defects are still common in metal components built with Additive Manufacturing (AM). Process monitoring methods for laser powder bed fusion (PBF-LB/M) are used in industry, but relationships between monitoring data and defect formation are not fully understood yet. Additionally, defects and deformations may develop with a time delay to the laser energy input. Thus, currently, the component quality is only determinable after the finished process.
Here, active laser thermography, a nondestructive testing method, is adapted to PBF-LB/M, using the defocused process laser as heat source. The testing can be performed layer by layer throughout the manufacturing process. We study our proposed testing method along experiments carried out on a custom research PBF-LB/M machine using infrared (IR) cameras.
Our work enables a shift from post-process testing of components towards in-situ testing during the AM process. The actual component quality is evaluated in the process chamber and defects can be detected between layers.
T2 - 2023 International Solid Freeform Fabrication Symposium
CY - Austin, TX, USA
DA - 14.08.2023
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Nondestructive Testing
KW - Thermography
KW - Defect Detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606288
DO - https://doi.org/10.26153/tsw/51096
SP - 1978
EP - 1989
PB - University of Texas at Austin
CY - Austin, TX, USA
AN - OPUS4-60628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - A comparison of machine learning approaches for porosity prediction in PBF-LB/M based on thermography
N2 - Metal-based additive manufacturing processes are increasingly used in industry to produce complex-shaped components. In this regard, the laser-based Powder Bed Fusion process (PBF-LB/M) is one of the key technologies due to its capability to produce components in high spatial accuracy. The formation of porosity during manufacturing poses a serious risk to the safety of the printed parts. For quality assessment, in-situ monitoring technologies such as thermography can be used to capture the thermal history during production. It was shown that discontinuities within the thermal history can be correlated with the probability of porosity or defect formation. In this context, Machine Learning (ML) algorithms have achieved promising results for the task of porosity prediction based on thermographic in-situ monitoring data. One important technique is the use of thermogram features for porosity prediction that are extracted from the raw data (e.g., features related to the melt pool geometry or spatter generation). However, the reduction from large thermogram data to discrete features holds the risk of losing potentially important thermal information and, thereby, introducing bias in the model.
Therefore, we present a raw data-based deep learning approach that uses thermographic image sequences for the prediction of local porosity. The model takes advantage of the self-attention mechanism that considers not only the thermogram information but also its positional context within the sequence. The model is used to predict porosity in the form of a many-to-one regression. It is trained and tested on a dataset retrieved from the manufacturing of HAYNES282 cuboid specimens. The model results are compared against state-of-the-art thermogram feature-based ML models and artificial neural networks. The raw data model outperforms its feature-based counterparts in terms of prediction scores and, therefore, seems to make better use of the information available in the thermogram data.
T2 - 4th Symposium on Materials and Additive Manufacturing
CY - Berlin, Germany
DA - 12.06.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Thermography
KW - Additive Manufacturing
KW - Machine learning
KW - Porosity prediction
PY - 2024
AN - OPUS4-62472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - SAMMIE - Research PBF-LB/M system for the development of in-situ monitoring methods
N2 - By allowing economic on-demand manufacturing of highly customized and complex workpieces, metal based additive manufacturing (AM) has the prospect to revolutionize many industrial areas. Since AM is prone to the formation of defects during the building process, a fundamental requirement for AM is to find ways to assure the safety and reliability of the additively manufactured parts to become applicable in most fields.
A possible solution for this problem lies in the deployment of various in-situ monitoring techniques. However, only a few of these techniques are commercially available and are not researched to an extent that allows to guarantee the adherence to strict quality and safety standards. Since commercial AM machines are not designed for research applications, they provide only limited access to the build chamber during the process and little control over the exact timing and parameters of the process. Therefore, for our research at BAM, we built a laser powder bed fusion system (PBF-LB/M), called “Sensor-based Additive Manufacturing MachInE” (SAMMIE). It provides a fully open system architecture with flexible accesses to the build camber and full control of the complete process. In this contribution, we show first results using thermographic cameras and optical tomography. The flexibility of SAMMIE allows us to use the multiple cameras either fixed relatively to the build plate or coaxially to the process laser.
T2 - 20th World Conference on Non-Destructive Testing (WCNDT)
CY - Incheon, South Korea
DA - 27.05.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Custom machine
KW - Additive Manufacturing
KW - Thermography
PY - 2024
AN - OPUS4-62471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - SAMMIE – Forschungssystem für die additive Fertigung von Metallen (PBF-LB/M) zur Entwicklung von In-situ-Überwachungs- und -prüfmethoden
N2 - Die additive Fertigung von Metallen hat inzwischen einen Reifegrad erreicht, der einen Einsatz in vielen Industriezweigen ermöglicht oder in greifbare Nähe rückt. Die Vorteile liegen vor allem in der Möglichkeit der Fertigung komplexer Bauteile, die sich konventionell nicht oder nur sehr aufwändig produzieren lassen, sowie in der Fertigung von hochindividualisierten Bauteilen in kleinen Stückzahlen. Allerdings ist der additive Fertigungsprozess hoch komplex und fehleranfällig. Um eine insbesondere für sicherheitsrelevante Bauteile notwendige Qualitätskontrolle zu gewährleisten, ist aktuell aufwändige nachgelagerte ZfP der einzelnen Bauteile notwendig. Alternativen könnten die In-situ-Prozessüberwachung und -prüfung bieten, die aktuell aber noch keinen ausreichenden Entwicklungsstand erreicht haben. Industrielle Fertigungsanlagen bieten keine oder nur geringe Flexibilität und Zugänglichkeit, um umfangreiche Untersuchungen auf diesem Gebiet zu ermöglichen. Daher haben wir an der BAM ein System für den Prozess des selektiven Laserschmelzens (PBF-LB/M) entwickelt, genannt SAMMIE. Es bietet eine komplett offene Systemarchitektur mit voller Kontrolle über den Prozess und flexiblem Zugang zur Baukammer, z.B. optisch sowohl direkt als auch koaxial zum Fertigungslaser. In diesem Beitrag stellen wir das System vor und zeigen erste experimentelle Ergebnisse der In-situ-Überwachung und -prüfung: Thermografische Schmelzbadüberwachung, optische Tomografie und In-situ-Laserthermografie. SAMMIE ermöglicht uns grundlegende Untersuchungen, die helfen werden, die In-situ-Prozessüberwachung und -prüfung weiterzuentwickeln, neue Erkenntnisse über die additive Fertigung zu gewinnen und die Sicherheit und Zuverlässigkeit des Prozesses zu verbessern.
T2 - DGZfP-Jahrestagung 2024
CY - Osnabrück, Germany
DA - 06.05.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Anlage
KW - Additive Fertigung
KW - Prozessüberwachung
KW - Additive Manufacturing
PY - 2024
AN - OPUS4-60149
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pelkner, Matthias
A1 - Altenburg, Simon
T1 - Sicher gedruckt
N2 - Sicherheitsrelevante Bauteile werden mittlerweile auch mit Hilfe der additiven Fertigung gedruckt. Allerdings ist die Qualifizierung aufgrund fehlender Überwachungssysteme weiterhin nicht vollständig und zufriedenstellend gelöst. Aus diesem Grund entwickelt die BAM Methoden und Prüfsystemen, die zur Onlineüberwachung des additiven Herstellungsprozesses eingesetzt werden. Der Artikel stellt die aktuellen Aktivitäten der BAM im Bereich der Thermografie und Wirbelstromprüfung für den PBF/LB-M-Prozess vor.
KW - Prozessüberwachung
KW - Wirbelstromprüfung
KW - Thermografie
KW - GMR/TMR
KW - PBF/LB-M
PY - 2024
UR - https://www.konstruktion-entwicklung.de/bessere-prozessueberwachung-fuer-sicherheitsrelevante-teile
UR - https://epaper.konstruktion-entwicklung.de/html5/DsTHKgm3cs/CMx70AIEQLMwE/1
VL - 5
IS - 2
SP - 14
EP - 17
PB - Schlütersche Fachmedien GmbH
CY - Hannover
AN - OPUS4-61781
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Breese, Philipp Peter
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Altenburg, Simon
T1 - A deep learning framework for defect prediction based on thermographic in-situmonitoring in laser powder bed fusion
N2 - The prediction of porosity is a crucial task for metal based additive manufacturing techniques such as laser powder bed fusion. Short wave infrared thermography as an in-situ monitoring tool enables the measurement of the surface radiosity during the laser exposure. Based on the thermogram data, the thermal history of the component can be reconstructed which is closely related to the resulting mechanical properties and to the formation of porosity in the part. In this study, we present a novel framework for the local prediction of porosity based on extracted features from thermogram data. The framework consists of a data pre-processing workflow and a supervised deep learning classifier architecture. The data pre-processing
workflow generates samples from thermogram feature data by including feature information from multiple subsequent layers.
Thereby, the prediction of the occurrence of complex process phenomena such as keyhole pores is enabled. A custom convolutional neural network model is used for classification. Themodel is trained and tested on a dataset from thermographic in-situ monitoring of the manufacturing of an AISI 316L stainless steel test component. The impact of the pre-processing parameters and the local void distribution on the classification performance is studied in detail. The presented model achieves an accuracy of 0.96 and an f1-Score of 0.86 for predicting keyhole porosity in small sub-volumes with a dimension of (700 × 700 × 50) μm3. Furthermore, we show that pre-processing parameters such as the porosity threshold for sample
labeling and the number of included subsequent layers are influential for the model performance. Moreover, the model prediction is shown to be sensitive to local porosity changes although it is trained on binary labeled data that disregards the actual sample porosity.
KW - Laser Powder Bed Fusion (PBF-LB/M, L-PBF)
KW - Selective Laser Melting (SLM)
KW - SWIR thermography
KW - Online monitoring
KW - Flaw detection
KW - Machine learning
KW - Convolutional neural networks (CNN)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575148
DO - https://doi.org/10.1007/s10845-023-02117-0
SN - 0956-5515
SP - 1
EP - 20
PB - Springer
AN - OPUS4-57514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Ulbricht, Alexander
A1 - Heinrich, Ph.
A1 - Baum, D.
A1 - Maierhofer, Christiane
A1 - Hilgenberg, Kai
T1 - In-Situ Defect Detection in Laser Powder Bed Fusion by Using Thermography and Optical Tomography—Comparison to Computed Tomography
N2 - Among additive manufacturing (AM) technologies, the laser powder bed fusion (L-PBF) is one of the most important technologies to produce metallic components. The layer-wise build-up of components and the complex process conditions increase the probability of the occurrence of defects. However, due to the iterative nature of its manufacturing process and in contrast to conventional manufacturing technologies such as casting, L-PBF offers unique opportunities for in-situ monitoring. In this study, two cameras were successfully tested simultaneously as a machine manufacturer independent process monitoring setup: a high-frequency infrared camera and a camera for long time exposure, working in the visible and infrared spectrum and equipped with a near infrared filter. An AISI 316L stainless steel specimen with integrated artificial defects has been monitored during the build. The acquired camera data was compared to data obtained by computed tomography. A promising and easy to use examination method for data analysis was developed and correlations between measured signals and defects were identified. Moreover, sources of possible data misinterpretation were specified. Lastly, attempts for automatic data analysis by data Integration are presented.
KW - Laser powder bed fusion (L-PBF)
KW - Selective laser melting (SLM)
KW - Additive manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
KW - Optical tomography
KW - Computed tomography (CT)
KW - Data fusion
KW - Lack-of-fusion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502417
DO - https://doi.org/10.3390/met10010103
VL - 10
IS - 1
SP - 103
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-50241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
T1 - Effects of inter layer time and build height on resulting properties of 316L stainless steel processed by laser powder bed fusion
N2 - Laser powder bed fusion (L-PBF) is the most prominent additive manufacturing (AM) technology for metal part production. Among the high number of factors influencing part quality and mechanical properties, the inter layer time (ILT) between iterative melting of volume elements in subsequent layers is almost completely unappreciated in the relevant literature on L-PBF. This study investigates the effect of ILT with respect to build height and under distinct levels of volumetric energy density (VED) using the example of 316L stainless steel. In-situ thermography is used to gather information on cooling conditions during the process, which is followed by an extensive metallographic analysis. Significant effects of ILT and build height on heat accumulation, sub-grain sizes, melt pool geometries and hardness are presented. Furthermore, the rise of defect densities can be attributed to a mutual interplay of build height and ILT. Hence, ILT has been identified as a crucial factor for L-PBF of real part components especially for those with small cross sections.
KW - Laser powder bed fusion (L-PBF)
KW - Laser beam melting (LBM)
KW - Selective laser melting (SLM)
KW - Dwell-time
KW - Thermography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503300
DO - https://doi.org/10.1016/j.addma.2020.101080
SN - 2214-8604
VL - 32
SP - 101080-1
EP - 101080-13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Nowakowski, Susanna
A1 - Altenburg, Simon
A1 - Maierhofer, Christiane
A1 - Hilgenberg, Kai
T1 - Experimental Determination of the Emissivity of Powder Layers and Bulk Material in Laser Powder Bed Fusion Using Infrared Thermography and Thermocouples
N2 - Recording the temperature distribution of the layer under construction during laser powder bed fusion (L-PBF) is of utmost interest for a deep process understanding as well as for quality assurance and in situ monitoring means. While having a notable number of thermal monitoring approaches in additive manufacturing (AM), attempts at temperature calibration and emissivity determination are relatively rare. This study aims for the experimental temperature adjustment of an off-axis infrared (IR) thermography setup used for in situ thermal data acquisition in L-PBF processes. The temperature adjustment was conducted by means of the so-called contact method using thermocouples at two different surface conditions and two different materials: AISI 316L L-PBF bulk surface, AISI 316L powder surface, and IN718 powder surface. The apparent emissivity values for the particular setup were determined. For the first time, also corrected, closer to real emissivity values of the bulk or powder surface condition are published. In the temperature region from approximately 150 °C to 580 °C, the corrected emissivity was determined in a range from 0.2 to 0.25 for a 316L L-PBF bulk surface, in a range from 0.37 to 0.45 for 316L powder layer, and in a range from 0.37 to 0.4 for IN718 powder layer.
KW - Emisssivity
KW - Laser Powder Bed Fusion (L-PBF)
KW - Selective Laser Melting (SLM)
KW - Additive Manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516148
DO - https://doi.org/10.3390/met10111546
VL - 10
IS - 11
SP - 1546
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-51614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
T1 - On the limitations of small cubes as test coupons for process parameter optimization in laser powder bed fusion of metals
N2 - The capability to produce complexly and individually shaped metallic parts is one of the main advantages of the laser powder bed fusion (PBF LB/M) process. Development of material and machine specific process parameters is commonly based on results acquired from small cubic test coupons of about 10 mm edge length. Such cubes are usually used to conduct an optimization of process parameters to produce dense material. The parameters are then taken as the basis for the manufacturing of real part geometries. However, complex geometries go along with complex thermal histories during the manufacturing process, which can significantly differ from thermal conditions prevalent during the production of simply shaped test coupons. This may lead to unexpected and unpredicted local inhomogeneities of the microstructure and defect distribution in the final part and it is a root cause of reservations against the use of additive manufacturing for the production of safety relevant parts. In this study, the influence of changing thermal conditions on the resulting melt pool depth of 316L stainless steel specimens is demonstrated. A variation of thermo-graphically measured intrinsic preheating temperatures was triggered by an alteration of inter layer times and a variation of cross section areas of specimens for three distinct sets of process parameters. Correlations between the preheating temperature, the melt pool depth, and occurring defects were analyzed. The limited expressiveness of the results of small density cubes is revealed throughout the systematic investigation. Finally, a clear recommendation to consider thermal conditions in future process parameter optimizations is given.
T2 - Icaleo 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Additive manufacturing
KW - Heat accumulation
KW - Thermal history
KW - In situ monitoring
KW - Representative specimens
KW - Thermography
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586558
DO - https://doi.org/10.2351/7.0001080
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
AN - OPUS4-58655
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
ED - Wei, Z.
ED - Pang, J.
T1 - On critical shifts of the process window due to heat accumulation in laser powder bed fusion
N2 - Safety-critical applications of products manufactured by laser powder bed fusion (PBF-LB/M) are still limited to date. This is mainly due to a lack of knowledge regarding the complex relationship between process, structure, and resulting properties. The assurance of homogeneity of the microstructure and homogeneity of the occurrence and distribution of defects within complexly shaped geometries is still challenging. Unexpected and unpredicted local inhomogeneities may cause catastrophic failures. The identification of material specific and machine specific process parameter windows for production of fully dense simple laboratory specimens is state of the art. However, the incorporation of changing thermal conditions that a complexly shaped component can be faced with during the manufacturing process is often neglected at the stage of a process window determination. This study demonstrates the tremendous effect of changing part temperatures on the defect occurrence for the broadly used stainless steel alloy AISI 316L. Process intrinsic variations of the surface temperature are caused by heat accumulation which was measured by use of a temperature adjusted mid-wavelength infrared (MWIR) camera. Heat accumulation was triggered by simple yet effective temporal and geometrical restrictions of heat dissipation. This was realized by a variation of inter layer times and reduced cross section areas of the specimens. Differences in surface temperature of up to 800 K were measured. A severe development of keyhole porosity resulted from these distinct intrinsic preheating temperatures, revealing a shift of the process window towards unstable melting conditions. The presented results may serve as a warning to not solely rely on process parameter optimization without considering the actual process conditions a real component is faced with during the manufacturing process. Additionally, it motivates the development of representative test specimens.
T2 - The 76th IIW Annual Assembly and International Conference On Welding And Joining (IIW 2023)
CY - Singapore, Singapore
DA - 16.07.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Laboratory specimens
KW - Process parameter optimization
KW - Heat accumulation
KW - Keyhole porosity
KW - Infrared thermography
PY - 2023
SP - 1
EP - 8
AN - OPUS4-58024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
A1 - Maierhofer, Christiane
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
A1 - Ulbricht, Alexander
A1 - Altenburg, Simon
T1 - Investigation of the thermal history of L-PBF metal parts by feature extraction from in-situ SWIR thermography
N2 - Laser powder bed fusion is used to create near net shape metal parts with a high degree of freedom in geometry design. When it comes to the production of safety critical components, a strict quality assurance is mandatory. An alternative to cost-intensive non-destructive testing of the produced parts is the utilization of in-situ process monitoring techniques. The formation of defects is linked to deviations of the local thermal history of the part from standard conditions. Therefore, one of the most promising monitoring techniques in additive manufacturing is thermography. In this study, features extracted from thermographic data are utilized to investigate the thermal history of cylindrical metal parts. The influence of process parameters, part geometry and scan strategy on the local heat distribution and on the resulting part porosity are presented. The suitability of the extracted features for in-situ process monitoring is discussed.
T2 - Thermosense: Thermal Infrared Applications XLIII
CY - Online meeting
DA - 12.04.2021
KW - SWIR camera
KW - Additive manufacturing (AM)
KW - Selective laser melting (SLM)
KW - Laser beam melting (LBM)
KW - In-situ monitoring
KW - Infrared thermography
PY - 2021
SN - 978-1-5106-4324-6
DO - https://doi.org/10.1117/12.2587913
VL - 11743
SP - 1
EP - 11
PB - SPIE - The international society for optics and photonics
AN - OPUS4-52535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
A1 - Scheuschner, Nils
A1 - Maierhofer, Christiane
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Thermography in laser powder bed fusion of metals: time over threshold as feasible feature in thermographic data
N2 - Thermography is one on the most promising techniques for in-situ monitoring of metal additive manufacturing processes. Especially in laser powder bed fusion processes, the high process dynamics and the strong focus of the laser beam cause a very complex thermal history within the produced specimens, such as multiple heating cycles within single layer expositions. This complicates data interpretation, e.g., in terms of cooling rates. A quantity that is easily calculated is the time a specific area of the specimen is at a temperature above a chosen threshold value (TOT). Here, we discuss variations occurring in time-over-threshold-maps during manufacturing of an almost defect free cuboid specimen.
T2 - 15th Quantitative InfraRed Thermography conference
CY - Online meeting
DA - 21.09.2020
KW - Additive Manufacturing
KW - Process monitoring
KW - Thermography
KW - L-PBF
KW - Time over threshold
PY - 2020
DO - https://doi.org/10.21611/qirt.2020.005
SP - 1
EP - 5
PB - QIRT Council
CY - Quebec, Canada
AN - OPUS4-52014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - In-situ Prozessüberwachung in der additiven Fertigung von Metallen mittels optischer Verfahren
N2 - Einer der aussichtsreichsten Ansätze, die Qualität und Sicherheit der gefertigten Teile in der metallbasierten additiven Fertigung (AM) zu erhöhen und die Notwendigkeit aufwändiger und zeitintensiver, zerstörender oder zerstörungsfreier Prüfungen (ZfP) nach der Fertigung zu verringern, liegt in dem Einsatz von in-situ Prozessüberwachungstechniken. Bereits jetzt werden erste Messsysteme zur Kontrolle der Energiequelle, des Bauraums, des Schmelzbades und der Bauteilgeometrie kommerziell angeboten. Weitere ZfP Verfahren, wie z.B. die aktive und passive Thermografie, werden in der Literatur als geeignet für die in-situ Anwendung angesehen, allerdings gibt es noch wenig konkrete praktische Umsetzungen, da die Möglichkeiten und individuellen Grenzen dieser Methoden, angewendet auf AM, noch nicht ausreichend erforscht sind. Aus diesem Grund verfolgt die BAM mit dem Projekt „Process Monitoring of AM“ (ProMoAM) im Themenfeld Material das Ziel, Verfahren des Prozessmonitorings zur in-situ Bewertung der Qualität additiv gefertigter Metallbauteile weiterzuentwickeln.
Im Beitrag wird zunächst das Projekt vorgestellt und anschließend der Fokus auf eine Messserie gelegt, in der Probekörper aus dem austenitischen Edelstahl 316L mit lokal variierenden Prozessparametern mittels selektiven Laserschmelzen (L-PBF) aufgebaut wurden. Der Bauprozess wurde hierbei durch das maschineneigene, koaxial arbeitende Photodiodensystem (Melt-Pool-Monitoring), einer Mittelwellen-Infrarotkamera und einer optischen Tomografiekamera im sichtbaren Wellenlängenbereich (Langzeitbelichtung für die Dauer eines Lagenaufbaus mit einer CMOS-Kamera mit hoher Ortsauflösung) simultan überwacht. Als Referenz für diese Methoden wurden die Probekörper mittels Computertomografie untersucht. Für die dabei anfallenden teils großen Datenmengen wurden Algorithmen für ein effizientes Preprocessing entwickelt. Es wurden Merkmale der Messdaten in Korrelation zu Fehlern und Inhomogenitäten extrahiert, welche für die einzelnen Methoden vergleichend vorgestellt und diskutiert werden.
T2 - 5. Tagung des Arbeitskreises Additiv gefertigte Bauteile und Strukturen
CY - Online meeting
DA - 04.11.2020
KW - Additive Fertigung
KW - Prozessüberwachung
KW - Thermografie
KW - Optische Tomografie
KW - Computertomografie
KW - L-PBF
KW - AM
KW - CT
KW - In-situ
PY - 2020
AN - OPUS4-51627
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
A1 - Kromm, Arne
T1 - Reparaturschweißen zukünftiger, in Betrieb befindlicher Wasserstoffpipelines
N2 - Wasserstoff leistet als Energieträger der Zukunft einen entscheidenden Beitrag zur nachhaltigen Energieversorgung, wobei der Transport auf Basis des europäischen Ferngasleitungsnetzes erfolgen wird. Bisherige Untersuchungen zur Werkstoffkompatibilität zeigen, dass die hier verwendeten, niedriglegierten Rohrstähle für Wasserstofftransport unter normalen Betriebsbedingungen (≤ 60 °C, max. 100 bar) grundsätzlich geeignet sind. Die Eignung kann nicht ohne Weiteres übertragen werden, sobald Reparaturschweißungen beispielsweise aufgrund von Wartungsarbeiten an druckführenden, in Betrieb befindlichen, Hochdruckgasleitungen erfolgen. Aus technisch-ökonomischen Gründen werden Schweißarbeiten dabei im Betrieb unter fortwährendem Druck und Gasfluss durchgeführt. Dies soll auch bei Wasserstoffpipelines erfolgen. Dazu im Erdgasnetz angewandte und etablierte Konzepte sind beispielsweise das „Hot-Tapping“ und „Stoppling“. Beim „Hot-Tapping“ wird eine druckführende Pipeline durch Anflanschen eines abgeschlossenen, druckdichten Systems aus Absperrventil und Bohrvorrichtung angebohrt. Dazu müssen sogenannte Überschieber (aus vorgeformten Zylinderhalbschalen) durch Längsnaht verbunden und dann mit Rohrrundnähten am Produktrohr verbunden werden. Für das zum überwiegenden Teil durchgeführte E-Hand-Schweißen sind dabei Vorwärmtemperaturen von ca. 100 °C bzw. 250 °C für die maximale Zwischenlagentemperatur einzuhalten. Besonderer Fokus liegt auf der Betrachtung dünnwandiger Leitungen, da hier beim Schweißen der Rundnähte die Austenitisierungstemperatur an der Innenseite der Pipeline überschritten wird. Dadurch wird eine signifikant höhere Wasserstoffaufnahme in den Leitungsstahl vermutet, mit einer möglichen Degradation der mechanischen Kennwerte bzw. Rissbildung. Durch die langen Schweiß- und Abkühlzeiten wird der Rohrleitungsstahl zudem teilweise stundenlang Temperaturen von bis zu 250 °C ausgesetzt. Neben der klassischen „Versprödung“ muss daher eventuell auch ein sogenannter Hochtemperatur-Wasserstoffangriff betrachtet werden. Diese vorliegende Studie gibt Einblick zur Übertragbarkeit der bekannten Konzepte aus der Erdgastechnik zum Reparaturschweißen. Dazu werden Möglichkeiten und Grenzen momentaner Prüfkonzepte sowie deren Weiterentwicklungen aufgezeigt. Dies umfasst bspw. geeignete Methodiken zur Werkstoffprüfung als auch skalierte Bauteilversuche unter realistischen Druckgas-Betriebsbedingungen einer Pipeline. In diesem Rahmen erfolgt auch die Kurzvorstellung des Kooperationsprojektes von BAM, DVGW und Ferngasnetzbetreibern „H2-SuD“ zum Einfluss der Temperaturführung und Rohrgeometrie auf die Wasserstoffaufnahme.
T2 - DVS CONGRESS 2024
CY - Erfurt, Germany
DA - 16.09.2024
KW - Reparaturschweißen
KW - Pipeline
KW - Wasserstoff
KW - Im Betrieb
PY - 2024
SN - 978-3-96144-269-0
VL - 395
SP - 341
EP - 349
AN - OPUS4-61478
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Einfluss trennender Fertigungsschritte auf die Eigenspannungen in additiv gefertigten Bauteilen aus hochfestem Stahl
N2 - Additive Fertigungsverfahren wie das Wire Arc Additive Manufacturing (WAAM) ermöglichen die effiziente Fertigung von gewichtsoptimierten endkonturnahen Strukturen in modernen Stahlkonstruktionen. Ihre Effizienz kann weiter durch die Verwendung von hochfesten Stählen gesteigert werden. Dies erlaubt eine signifikante Einsparung von Kosten, Zeit und Ressourcen. Entsprechende Schweißzusatzwerkstoffe für Lichtbogenschweißverfahren sind kommerziell verfügbar. Fehlende Richtlinien und fehlende quantitative Kenntnisse über die schweißtechnische Beanspruchung während der Fertigung und im Betrieb limitieren den industriellen Einsatz stark. Daher werden in einem aktuellen Vorhaben (IGF-Nr. 21162 BG) der BAM und TU Chemnitz die wesentlichen Einflüsse und komplexen Interaktionen durch Werkstoff, Fertigungsprozess, Konstruktion und trennende Fertigungsschritte auf den Beanspruchungszustand untersucht. Der vorliegende Beitrag fokussiert hierfür die Auswirkungen trennender Fertigungsschritte auf Verzug und Eigenspannungen definierter WAAM-Prüfkörper. Die Eigenspannungsanalyse erfolgt mittels Röntgenbeugung. Die große Anzahl an Ergebnissen von zuvor untersuchten Referenzproben, die mit einem speziellen WAAM-Massivdraht (Streckgrenze >820 MPa) bei unterschiedlicher Wärmeführung und Geometrie vollautomatisiert geschweißt wurden, lässt eine Korrelation der Messdaten zu. Hierzu erfolgt die Analyse des Ausgangszustandes und abschließend des Zustandes nach trennender Bearbeitung, welche begleitend mittels digitaler Bildkorrelation hinsichtlich des Verzuges untersucht wurden. So ist zu beobachten, dass die Geometrie deutlichen Einfluss auf Relaxation und Umlagerung der Eigenspannungen hat und damit die Risssicherheit positiv beeinflussen kann.
T2 - Werkstofftechnisches Kolloquium 2023 Chemnitz
CY - Chemnitz, Germany
DA - 29.03.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
AN - OPUS4-57690
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Stresses in repair welding of high-strength steels Part 1: Restraint and Cold cracking risk
N2 - The sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures, like mobile or ship cranes. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of global and local welding-induced stresses may lead to crack formation and component failure, particularly in interaction with the degradation of the microstructure and mechanical properties of high-strength steels during the repair process. However, manufacturers hardly have any information about these issues and there is a lack of recommendations and guidelines to take these safety-relevant aspects into account in adequate repair concepts. The aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines to avoid cold cracking, damage and expensive reworking especially for high-strength steels. Part 1 of this study involves systematic investigations of influences of shrinkage restraint during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures. The quantification of the shrinkage restraint of repair weld joints was achieved by means of experimental and numerical restraint intensity analysis. In welding experiments with self-restrained slot specimens, restraint intensity and introduction of hydrogen via the welding arc using anti spatter spray were varied systematically to analyse the effect on welding result, residual stresses, and cold cracking. It could be shown that increasing restraint intensities result in significantly higher transverse residual stress levels. In the case of hydrogen introduction S500MLO showed no cold cracking independent of the restraint conditions. However, S960QL was found to be considerably cold cracking sensitive if hydrogen is introduced. With increasing restraint intensity length and number of cold cracks increases significantly. Part 2 [1] of this study is focussed on microstructure and residual stresses due to gouging and stress optimization via adequate heat control parameters in repair welding.
T2 - IIW Annual Assembly 2023
CY - Singapore
DA - 16.07.2023
KW - Repair-welding
KW - MAG welding
KW - High-strength steels
KW - Cold cracking
KW - Residual stresses
PY - 2023
AN - OPUS4-59253
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Lippold, J. C.
A1 - Farajian, M.
A1 - Kannengießer, Thomas
A1 - Scotti, A.
A1 - Raufelder, E.
T1 - Welding in the world - 2024 update
N2 - This is an editorial regarding the performance of the journal "Welding in the World" in the year 2023 (vol. 67).
KW - Journal performance
KW - Editorial
PY - 2024
DO - https://doi.org/10.1007/s40194-024-01686-9
SN - 0043-2288
SN - 1878-6669
VL - 68
SP - 179
EP - 181
PB - Springer
CY - Berlin
AN - OPUS4-63013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Czeskleba, Denis
T1 - Kurzvorstellung des Projektes "H2SuD / Wasserstoff und Schweißen Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen"
N2 - Die Wasserstoffinfrastruktur ist eine zentraler Bestandteil der erfolgreichen Umsetzung der wasserstoffbasierten Energiewende. Dabei bilden Ferngasleitungen quasi das "Rückgrat" der Transportinfrastruktur großer Gasmengen. Dabei müssen unter Umständen Reparaturen an den Pipelines durchgeführt werden. Dabei ist in der Erdgasinfrastruktur das Schweißen an in Betrieb befindlichen (d.h. von Gas durchflossenen) Pipelines Stand der Technik. Es ist jedoch vollkommen offen, inwieweit diese Technik auf die reine Wasserstoffpipelines übertragbar sind. Hierzu leistet das Projekt H2SuD wichtige Beiträge zur Aufklärung des Einfluss eines Reparaturschweißprozesses auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen.
T2 - Sitzung des FA1 "Schweißmetallurgie" der Forschungsvereinigung Schweißen und verwandte Verfahren des DVS e.V.
CY - Aachen, Germany
DA - 22.02.2023
KW - Wasserstoff
KW - Pipeline
KW - Reparatur
KW - Schweißen
KW - Ferngasleitung
PY - 2023
AN - OPUS4-57087
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Component test to simulate critical conditions of hydrogen assisted cracking in submerged arc welded offshore steel
N2 - Offshore Wind Turbines (OWT) are a key factor in tomorrow's sustainable energy generation. The ever� increasing installation depth and weight of OWTs require suitable foundation concepts such as monopiles or tripods. Typically, mild steels such as S420ML are used with plate thicknesses of up to several hundred mm, resulting in high restraints in the welded joints. The large plate thickness requires high-efficiency welding processes such as submerged arc welding (SAW) with multiple wires. Due to the very high stiffness and plate thickness of the large-scale offshore structure, a susceptibility to time� delayed hydrogen assisted cracking (HAC) may occur. For this reason, a minimum waiting time (MWT) of up to 48 h must be considered before NDT is conducted. The evaluation of the crack susceptibility is complex due to the component size and stiffness of real offshore structures. For this purpose, a near-component test geometry has been developed to transfer the real stiffness conditions to laboratory (i.e. workshop) scale. The 350 kg mock-up consisted of heavy plates (thickness 50 mm, seam length 1,000 m) joined by a 22-pass submerged-arc weld. Additional stiffeners simulated the effect of high restraint or shrinkage restraint of the weld. Extreme scenarios of hydrogen absorption during welding were simulated by using flux in dry (HD < 5 ml/100g Fe) and wet (HD > 15 ml/100g Fe) conditions. Weld residual stresses were determined using a robotic X-ray diffractometer. Areas of critical tensile residual stress (at the yield strength level) were found in the weld metal and in the heat affected zone, suggesting that these weld subzones are the most critical in the case of hydrogen ingress. To identify possible delayed cracking, the welds were inspected by phased array ultrasonic testing (PAUT) after welding, 6 h, 12 h, 24 h, and a maximum of 48 h. Summarized, no significant occurrence of HAC was detected, indicating the high crack resistance of the welded joint, i.e., a suitable combination of base material, welding consumable and parameters.
T2 - Materials Week/Steel Innovation
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - Cold cracking
KW - Component test
KW - Hydrogen
KW - Minimum waiting time
KW - Offshore steel grade
PY - 2025
AN - OPUS4-62873
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Gruskovà, J.
A1 - Martin, G.
A1 - Kresten, O.
A1 - Mitthoff, F.
A1 - Kaska, K.
A1 - Hofmann, C.
A1 - Kreuzer, W.
A1 - Phelps, M.
A1 - Boydston, K.
A1 - Easton Jr., R. L.
A1 - Knox, K. T.
A1 - Kelbe, D.
A1 - Kasotakis, D.
A1 - Christens-Barry, W. A.
A1 - Stewart, D.
A1 - Rabin, Ira
A1 - Hahn, Oliver
A1 - Glaser, L.
A1 - Garrevoet, J.
A1 - Shevchuk, I.
A1 - Klumpp, S.
A1 - Deckers, D.
A1 - Buck, J.
ED - Cronier, M.
ED - Mondrain, B.
T1 - Insights-into-the-Digital-Recovery-of-the-Scythica-Vindobonesia
N2 - The Scythica Vindobonensia, the new fragments on Gothic incursions into Roman provinces in the Balkans in the middle of the third century AD that were revealed some years ago in a Greek palimpsest at the Austrian National Library in Vienna (ÖNB), are commonly considered as one of the most important additions of the last decades to the corpus of texts from classical Antiquity. Tere is a high degree of confdence among scholars in supposing that the fragments come from the lost work Scythica written in Greek by the third-century historian P. Herennius Dexippus (Δέξιππος) of Athens. The new fragments have hence also been called Dexippus Vindobonensis. In his Scythica, Dexippus recorded wars of the Romans with the Goths (and other tribes) whom he called Scythians.
The work had been hitherto known only from excerpts and quotes by later authors. Eight pages of a Byzantine manuscript copy of the ancient text have survived hidden underneath the visible surface of the last four parchment folios of the Vienna manuscript Historicus graecus 73, f. 192r -195v4. The copy is written in a Greek calligraphic minuscule which has been estimated by palaeographers to be of the middle or the second half of the eleventh century. In the thirteenth century, the text (on each of the eight pages arranged in one column, with 30 lines per page) was washed of the parchment and the valuable material made from animal skin was re-used for Christian texts. The new writing largely covered the faded remnants of the original text. It thus became hidden from the human eye for more than seven hundred years. Its discovery by Jana Grusková, a classical philologist specialized in the transmission of Greek texts, resulted from a systematic review of all Greek palimpsests kept at the Austrian National Library in Vienna at the beginning of the twenty-first century and a detailed examination of the four folios in 2007-20097.
KW - Scythica Vindobonensia,
KW - Gothic incursions
KW - A Greek palimpsest
KW - Antiquity
KW - Byzantine manuscript
KW - Vienna manuscript
PY - 2020
SN - 978-2-916716-81-7
SN - 0577-1471
VL - 2020
IS - 24/1
SP - 945
EP - 967
PB - Association des Amis du Centre d’Histoire et Civilisation de Byzance
CY - Paris
ET - 1
AN - OPUS4-53843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schaupp, Thomas
T1 - Modified TEKKEN test for studying hydrogen-assisted cracking in high-strength structural steels
N2 - In the present work, the complex interactions of the influences of material, welding process and seam configuration and the restraint of shrinkage on the residual stresses and the influence of diffusible hydrogen on hydrogen-assisted cracking (HAC) in the high-strength steel S960QL were investigated. For this purpose, self-restraint specimens were selected using the TEKKEN test with correspondingly adapted seam opening angles and a restraint intensity of approx. RFy = 17 kN/(mm·mm). The variation of the seam opening angle of the test seams was between 30° and 60°. Due to the comparatively high restraint of shrinkage in the transverse direction of the weld, high tensile residual stresses in the weld metal were expected for both weld seam configurations. In addition, a dehydrogenation heat treatment (DHT) for HAC prevention under restraint of shrinkage was verified. In order to keep distortion and heat input as low as possible, the seam geometries were manufactured from the solid material by means of electric discharge machining (EDM). Both, solid wire and metal cored wire were used. In addition, hydrogen was added to the shielding gas in solid wire welding to increase diffusible hydrogen concentration. Moreover, welding residual stresses at the weld seam surface, which were measured by using mobile X-ray diffraction, were taken into account to evaluate the HAC behavior. DHT was carried out at 250 °C for 4 h in an external furnace.
T2 - 73rd IIW Annual Assembly: Commission II-A
CY - Online meeting
DA - 15.07.2020
KW - High-strength steel
KW - Gas metal arc welding
KW - Hydrogen-assisted cracking
KW - TEKKEN test
KW - Residual stresses
KW - Dehydrogenation heat treatment
PY - 2020
AN - OPUS4-51035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
A1 - Erxleben, Kjell
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Herausforderungen beim Schweißen im Betrieb an Wasserstoff-Ferngasleitungen
N2 - Als Energieträger der Zukunft kommt grünem Wasserstoff große Bedeutung bei der Energiewende und der zukünftigen, nachhaltigen Energieversorgung zu Teil. Zum effizienten und sicheren Transport des Wasserstoffs ist die Bereitstellung einer Pipeline-Infrastruktur geplant. Die meisten Länder verfolgen hierbei die Strategie der Umwidmung bestehender Erdgastransportleitungen, ergänzt durch Errichtung neuer Pipelines. Die bestehenden Erdgasnetze sind dabei aus unterschiedlichsten Rohrgeometrien und Materialien zusammengesetzt. Bei der Umwidmung von Erdgaspipelines zum Transport von Wasserstoff müssen daher Fragen der Materialverträglichkeit hinsichtlich des als Wasserstoffversprödung bekannten Phänomens der Beeinträchtigung der mechanischen Eigenschaften metallischer Werkstoffe durch Wasserstoff betrachtet werden. Bisherige Forschungsergebnisse und Feldversuche deuten darauf hin, dass die niedriglegierten, ferritischen Stähle, aus denen die Ferngasleitungen des Erdgasnetzes überwiegend bestehen, für den Transport von Wasserstoff unter normalen Betriebsbedingungen geeignet sind. Eine Frage, die bislang weniger Aufmerksamkeit erhielt, ist die, wie sich das Schweißen im Betrieb an Wasserstoffpipelines auf die Materialkompatibilität auswirkt. Im Erdgasnetz sind etablierte Verfahren wie beispielsweise das „Hot-Tapping“ unumgänglich für die Instandhaltung und Erweiterung des Netzes. Hierbei werden an eine im Betrieb befindliche Pipeline geteilte T-Stücke aufgeschweißt, über die die Pipeline dann mit geeigneten Bohrvorrichtungen während eines ununterbrochenen Betriebs angebohrt werden kann. Um zu beurteilen, ob diese Verfahren gefahrlos auf Wasserstoffpipelines übertragen werden können, müssen Problemstellungen betrachtet werden, die sich durch den Wärmeeintrag ins Material beim Schweißen ergeben. Wasserstofflöslichkeit und Diffusionsgeschwindigkeit sind temperaturabhängig. Erhöhte Temperaturen könnten eine Wasserstoffaufnahme ins Material bewirken, die zu einer kritischen Degradation der mechanischen Eigenschaften des Materials führen könnte. Die Temperaturen, die beim Schweißen erreicht werden, führen lokal zur Überschreitung der Austenitisierungstemperatur. Austenit weist eine deutlich höhere Löslichkeit von Wasserstoff auf, während die Diffusionsgeschwindigkeit des Wasserstoffs in dieser Phase deutlich herabgesetzt ist. Es wird vermutet, dass dies zu einer lokal erhöhten Wasserstoffkonzentration führt. Damit geht ein erhöhtes Risiko einer kritischen Materialdegradation einher. Durch die lange Zeitdauer beim Schweißen von mehrlagigen Rundkehlnähten an großen Pipelines, einschließlich einer möglichen Vorwärmprozedur, ist weiterhin zu klären, ob der aus Anwendungsfällen in der Petrochemie bekannte Hochtemperaturwasserstoffangriff auftritt. Der vorliegende Beitrag liefert einen Überblick über das Schweißen im Betrieb an Gaspipelines, hierbei auftretenden Herausforderungen bei der möglichen Anwendung auf Wasserstoffleitungen. Dabei werden auch aktuelle Forschungsprojekte zum Thema Schweißen an Wasserstoffpipelines im Betrieb eingehend diskutiert. In diesem Zusammenhang werden erste Ergebnisse des gemeinschaftlichen Forschungsprojektes „H2-SuD: Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2-Ferngasleitungen“ des Deutschen Vereins des Gas- und Wasserfaches (DVGW), der Bundesanstalt für Materialforschung und -prüfung (BAM) und deutscher Gasnetzbetreiber (Open Grid Europe, ONTRAS Gastransport, u.v.m.) präsentiert.
T2 - 53. Sondertagung - Schweißen im Anlagen-und Behälterbau 2025
CY - Munich, Germany
DA - 18.03.2025
KW - Materialdegradation
KW - Pipeline
KW - Schweißen
KW - Wasserstoff
PY - 2025
SN - 978-3-96144-290-4 (Print)
SN - 978-3-96144-291-1 (E-Book)
VL - 2025
SP - 106
EP - 115
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-62911
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Schweißen im Wasserstoffanlagen- und Behälterbau - Eine Kurzübersicht
N2 - Wasserstoff erfüllt die zentrale Rolle für die Umwandlung der bisherigen fossil-basierten Energieerzeugung und -nutzung auf eine dekarbonisierte, nachhaltige Form. Dazu muss der Wasserstoff erzeugt, gespeichert, transportiert werden, bevor er wieder der Nutzung zugeführt wird. Hierzu sind entlang der gesamtem Prozesskette Wasserstofftechnologien notwendig, die einen sicheren Betrieb erfordern. Hierbei kommt dem schweißtechnischen Anlagen- und Behälterbau wesentliche Bedeutung zu, insbesondere (aber nicht ausschließlich) für Speicherung und Transport des Wasserstoffes. Der vorliegende Beitrag gibt einen kurzen Überblick, wo und wie die konventionelle Schweißtechnik hierzu wichtige Beiträge leistet. Die additive Fertigung, also das „Drucken“ von Bauteilen wird dabei zunehmend wichtiger, entlang der gesamtem Prozesskette der Wasserstofftechnologien. Gleichwohl darf nicht unterschätzt werden, dass auch wesentlicher Bedarf an der Erweiterung und teilweiser Neufassung von bestehenden Regel- und Normenwerken besteht.
T2 - 51. Sondertagung "Schweißen im Behälter- und Anlagenbau"
CY - Munich, Germany
DA - 01.03.2023
KW - Wasserstoff
KW - Anlagenbau
KW - Schweißen
KW - Studie
KW - Pipeline
PY - 2023
SN - 978-3-96144-219-5
VL - 387
SP - 83
EP - 88
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-57075
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Herstellung und Charakterisierung von WAAM-Bauteilen aus hochfesten Zusatzwerkstoffe
N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein.
Im vorliegenden Beitrag werden einige Verarbeitungsempfehlung auf Basis der Ergebnisse für den Arbeitskreis des DVS AG V 12 (Additive Fertigung) abgeleitet.
T2 - Sitzung der DVS Arbeitsgruppe (AG) V 12 Additive Fertigung
CY - Online meeting
DA - 23.11.2022
KW - MAG-Schweißen
KW - Additive Fertigung
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Kaltrisssicherheit
KW - Wärmeführung
KW - Windenergie
PY - 2022
AN - OPUS4-56721
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ziegler, Mathias
A1 - Altenburg, Simon
A1 - Krankenhagen, Rainer
A1 - Maierhofer, Christiane
A1 - Scheuschner, Nils
A1 - Marquardt, E
A1 - Mühlberger, W.
A1 - Nagel, F.
A1 - Neumann, E.
A1 - Rohwetter, P.
A1 - Rutz, F.
A1 - Schwake, C.
A1 - Schramm, S.
A1 - Schwaneberg, F.
A1 - Taubert, R. D.
T1 - Thermografie und Strahlungsthermometrie - Stand und Trends
N2 - In vielen Umgebungen, besonders bei hohen Temperaturen, korrosiven Umgebungen oder auf bewegten oder schlecht zugänglichen Flächen, kann die Temperatur nicht oder nur mit nicht akzeptablem Aufwand mit Berührungsthermometern gemessen werden. Diese Umgebungsbedingungen sind unter anderem in der chemischen Industrie, der Lebensmittel-, Metall-, Glas-, Kunststoff- und Papierherstellung sowie bei der Lacktrocknung anzutreffen. In diesen Bereichen kommen Strahlungsthermometer zum Einsatz. Der VDI-Statusreport zeigt typische Anwendungsfelder von nicht radiometrisch kalibrierten Wärmebildkameras und von radiometrisch kalibrierten Thermografiekameras. Um verlässlich mit spezifizierten Messunsicherheiten berührungslos Temperaturen zu messen, müssen die Strahlungsthermometer und Thermografiekameras nicht nur kalibriert, sondern radiometrisch und strahlungsthermometrisch umfassend charakterisiert werden. Auch die optische Materialeigenschaft, der spektrale Emissionsgrad und die Gesamtstrahlungsbilanz (Strahlung des Messobjekts und der Umgebung) sind bei der industriellen Temperaturmessung von großer Bedeutung. In den letzten Jahrzehnten ist dazu ein umfassendes technisches Regelwerk entstanden, das wir Ihnen mit diesem VDI-Statusreport vorstellen. Manche in den Richtlinien beschriebenen Kennwerte mögen abstrakt wirken. In diesem Statusreport zeigen wir an konkreten Beispielen, was diese Kenngrößen für die berührungslose Temperaturmessung bedeuten. Beispiele von Anwendungen zeigen, wo temperaturmessende Thermografiekameras und ausschließlich bildgebende Wärmebildkameras in der Praxis eingesetzt werden. Mit einer Analyse, welche Themen und Anwendungen derzeit besonders intensiv diskutiert werden, versuchen wir Trends für zukünftige Entwicklungen herauszuarbeiten.
KW - Thermografie
KW - Temperaturmessung
PY - 2021
UR - https://www.vdi.de/ueber-uns/presse/publikationen/details/thermografie-und-strahlungsthermometrie-stand-und-trends
SP - 1
EP - 40
PB - VDI Verein Deutscher Ingenieure e.V.
CY - Düsseldorf
AN - OPUS4-52904
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Measurement of real temperatures in metal powder bed fusion: Hyperspectral thermography
N2 - Detailed knowledge about the physics of the PBF-LB/M process is still lacking, and the simulation of the fast and small-scale process is challenging. Especially the experimental validation of complex simulations lacks a suitable measurement technique for temperature distributions at high speeds and spatial resolution. The complicated process physics, specifically the rapidly changing emissivity in and around the meltpool, pose a severe challenge for usual thermographic approaches.
Here, we present first results of a hyperspectral measurement approach to reconstruct temperature and emissivity maps during the PBF-LB/M process in a custom manufacturing machine. The camera setup measures the thermal radiation of the process along a line at a rate of 20 kHz, spectrally resolved between 1 µm and 1.6 µm. When the meltpool travels perpendicularly across this line, a typical meltpool can be reconstructed by pointwise fitting for temperature emissivity separation, based on typical spectral emissivities from reference measurements.
T2 - Lasers in Manufacturing Conference - LiM
CY - Munich, Germany
DA - 23.06.2025
KW - PBF-LB/M
KW - In situ monitoring
KW - Thermography
KW - Additive Manufacturing
KW - Process monitoring
KW - Hyperspectral
PY - 2025
AN - OPUS4-63564
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - Fundamentals of quantitative temperature determination during laser powder bed fusion of metals (PBF-LB/M) via hyperspectral thermography
N2 - Additive manufacturing (AM, also known as 3D printing) of metals is becoming increasingly important in industrial applications. Reasons for this include the ability to realize complex component designs and the use of novel materials. This distinguishes AM from conventional manufacturing methods such as subtractive manufacturing (turning, milling, etc.). The most widely used AM process for metals is laser powder bed fusion (PBF-LB/M, also known as selective laser melting SLM). Currently, it has the highest degree of industrialization and the largest number of machines in use. In PBF-LB/M, the feedstock is present as metal powder in an inert gas atmosphere inside a process chamber where a laser melts it locally. By repeatedly lowering the build platform, applying a new layer of powder, and then selectively melting it with the laser, a component is built up layer by layer. The local temperature distributions that occur during this process determine not only the properties of the finished component, but also the possible formation of defects such as pores and cracks. Due to the high relevance of the thermal history for precise geometries and defect formation, a temporally and spatially resolved measurement of quantitative (or real/actual) temperatures would be optimal. Quantitative values would ensure comparability and repeatability of the AM process which would also positively affect the quality and safety of the manufactured component. Furthermore, it would also contribute to the validation of simulations and to a deeper understanding of the manufacturing process itself.
At present, however, only qualitative monitoring of the thermal radiation is performed (e.g., by monitoring the melt pool using a photodiode), and safety-relevant components must be inspected ex situ afterwards which is time-consuming and costly. A reason for the lack of quantitative temperature data from the process are the challenging conditions of the PBF-LB/M process with high scanning speeds and a small laser spot diameter. Furthermore, the emissivity of the surface changes at high dynamics (temporally/spatially) as well as with temperature and wavelength. This specifically makes contactless temperature determination based on emitted infrared radiation challenging for PBF-LB/M. Although classical thermography offers very good qualitative insights, it is not sufficient for a reliable quantitative temperature determination without a complex temperature calibration including image segmentation and assignment of previously determined emissivities.
For this reason, this publication presents the hyperspectral thermography approach for the PBF-LB/M process: The emitted infrared radiation is measured simultaneously at many adjacent wavelengths. In this study, this is realized via a fast hyperspectral line camera that operates in the short-wave infrared range. The thermal radiation of a line on the target is spectrally dispersed and detected to measure the radiant exitance along that line. If the melt pool of the PBF-LB/M process moves through this line at a sufficient frame rate, a spatial reconstruction of an effective melt pool is possible.
One approach to determine the desired emissivities and the quantitative temperature from this hyperspectral data are temperature-emissivity separation (TES) methods. A major problem is that n spectral measurements are available, but n+1 parameters are required for each image pixel (n emissivity values + one temperature value). TES methods offer the possibility to approximate this mathematically underconstrained problem in a reliable and traceable way by analytically parameterizing the spectral emissivity with a few degrees of freedom. Using this approach, setup and method are applied to a research machine for PBF-LB/M, called SAMMIE (Sensor-based Additive Manufacturing Machine). First results under AM process conditions are shown which form the basis for the determination of quantitative temperatures in the PBFLB/M process. This marks an important contribution to improving the comparability and repeatability of production, validating simulations, and understanding the process itself. When fully developed and validated, the presented method can also provide reference measurements to evaluate and optimize other, more practical monitoring methods, such as melt pool monitoring or optical tomography. In the long run, this will help to increase confidence in the safety of AM products.
T2 - QIRT 2024
CY - Zagreb, Croatia
DA - 01.07.2024
KW - Additive Manufacturing
KW - Additive Fertigung
KW - Real Temperature
KW - Melt Pool
KW - Emissivity
PY - 2024
AN - OPUS4-60762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Characterization of hydrogen trapping in a CoCrFeMnNi high-entropy alloy charged up to 1000 bar high-pressure hydrogen
N2 - First studies on the mechanical behavior of high-entropy alloys (HEAs) in high-pressure hydrogen environment are available. In contrast, the underlying hydrogen absorption, diffusion and trapping in these HEAs like the Cantor-alloy was less in the scientific scope so far. For that reason, the CoCrFeMnNi-HEA was compared to a conventional AISI 316L austenitic steel, by exposing to high-pressure hydrogen charging at 200 bar and very-high pressure at 1,000 bar. Thermal desorption analysis (TDA) was applied with different heating rates (0.125 K/s to 0.500 K/s), see Fig. 1a to d. The underlying TDA spectra were analyzed in terms of a reasonable peak deconvolution to into a defined number of peaks and the calculation of the activation energies for the respective and predominant hydrogen trap sites. Both materials show a comparable hydrogen diffusivity. The obtained activation energies suggest that in case of the CoCrFeMnNi-HEAs an interaction of the austenitic phase as well as the direct atomic bonding of hydrogen to the metal atoms are the dominant traps, since “impurities” such as carbides or inclusions are only present in trace amounts. Available literature suggests that the Cr and Mn-content is here of special interest for the direct hydrogen bonding at solute atoms. In addition, the trap occupancy rate must be considered in terms of a pressure-related hydrogen absorption. The derived apparent hydrogen solubility was in the order: 316L < CoCrFeMnNi-HEA for both charging pressures. Especially, the 1,000 bar values lead to noteworthy results with > 70 wt.ppm for the AISI 316L and >130 wt.ppm for the CoCrFeMnNi. In fact, both the hydrogen diffusion and trapping data on gaseous high-pressure hydrogen charged HEAs are rare so far. The results of the present study allow a deeper understanding of hydrogen trapping in the regarded CoCrFeMnNi-system.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genoa, Italy
DA - 26.06.2025
KW - Hydrogen
KW - Thermal desorption analysis
KW - High-pressure charging
KW - Trapping
KW - Diffusion
PY - 2025
AN - OPUS4-63542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Treutler, K.
A1 - Wesling, V.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Modification of Co–Cr alloys to optimize additively welded microstructures and subsequent surface finishing
N2 - Cobalt chromium alloys are often used in turbine and plant construction. This is based on their high thermal and mechanical stress resistance as well as their high wear resistance to corrosive and abrasive loads. However, cobalt is a cost-intensive material that is difficult to machine. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components in many sectors. Concerning inhomogeneity and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. As a result of the high stresses on the components
and requirements for a high surface quality, a complementary use of additive and machining manufacturing processes is necessary. Thereby, Co–Cr alloys are extremely challenging for machining with geometrically defined cutting edges because of their low thermal conductivity combined with high strength and toughness. An approach to solve this problem is to refine and homogenise the microstructure. This is achieved by modifying the alloy with elements zirconium and hafnium, which are added up to a maximum of 1 wt.-%. A reduction of the process forces and stresses on the tool and work piece surface is also achievable via hybrid milling processes. There are already studies on the combined use of additive and machining manufacturing processes based on laser technology. However, knowledge based on powder and wire-based arc processes is important, as these processes are more widespread. Furthermore, the effects on the surface zone of additively manufactured components by hybrid finish milling have not yet been a subject of research. The results show that the structural morphology could be significantly influenced with the addition of zirconium and hafnium.
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Plasma-transferred arc welding
KW - Co-Cr-alloy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554182
DO - https://doi.org/10.1007/s40194-022-01334-0
SN - 0043-2288
SN - 1878-6669
SP - 1
EP - 13
PB - Springer
CY - Heidelberg
AN - OPUS4-55418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Treutler, K.
A1 - Schröpfer, Dirk
A1 - Wesling, V.
A1 - Kannengießer, Thomas
T1 - Investigations on influencing the microstructure of additively manufactured Co‑Cr alloys to improve subsequent machining conditions
N2 - Co-Cr alloys are frequently used for highly stressed components, especially in turbine and plant construction, due to their high resistance to thermal and mechanical stress, as well as to corrosive and abrasive loads. Furthermore, they are classified as difficult-to-cut materials because of their high strength and toughness as well as their low thermal conductivity. However, for Co, an increased cost and supply risk can be observed in recent years. Therefore, additive manufacturing (AM) offers significant economic advantages due to higher material efficiency regarding repair, modification, and manufacturing of such components. Concerning inhomogeneity and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. In addition, subsequent machining, particularly contour milling, is essential to generate the required complex contours and surfaces. Hence, additive and machining manufacturing processes need to be coordinated in a complementary way, especially due to additional challenges arising in milling of heterogeneous hard-to-cut microstructures. Recently, it has been shown that modern, hybrid cutting processes, such as ultrasonic-assisted milling (US), can improve the cutting situation. In this investigation, the Co-Cr initial alloy is additionally modified with Ti and Zr up to 1 wt% with the aim to enhance the homogeneity of the microstructure and, thus, the machinability. Hence the investigation includes finish milling tests of the AM components and the comparison of US and conventional machining. Both the modifications and the ultrasonic assistance exhibit a significant effect on the machining situation; for example US causes a higher surface integrity of the finish milled surfaces compared to conventional milling.
T2 - International Congress on Welding, Additive Manufacturing and associated non-destructive testing
CY - Online meeting
DA - 08.06.2022
KW - Cobalt-chromium alloy
KW - Additive manufacturing
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560917
DO - https://doi.org/10.1007/s40194-022-01397-z
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-56091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Amadeus
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Determination of residual stress evolution during repair welding of high-strength steel components
N2 - During the assembly of steel structures, unacceptable weld defects may be found. An economical solution is local thermal gouging of the affected areas and re-welding. Due to high shrinkage restraints of repair weld and sur- rounding structure, high global and local welding stresses superimpose, and may lead to cracking and component failure, especially in connection with the degraded microstructure and mechanical properties of high-strength steels during the repair process. Component-related investigations of high-strength steels (FOSTA P1311/ IGF20162N) focus on welding residual stress evolution during local thermal gouging and rewelding. In this study, repair welding of S500MLO (EN 10225) is carried out using in-situ digital image correlation (DIC) and ex- situ X-ray diffraction (XRD) to analyse strains and stresses. Self-restrained slit specimen geometries were identified representing defined rigidity conditions of repair welds of real components, which were quantified using the restraint intensity concept. The specimens were rewelded with constant welding heat control and parameters. Weld specimens exhibited significantly increased transverse residual stresses with higher transverse restraint intensities, in the weld metal, and in the heat affected zone. Transverse stresses along the weld seam decrease at the weld seam ends leading to different stress state during gouging and welding. XRD analysis of the longitudinal and transverse local residual stresses after cooling to RT showed a good comparability with global DIC analyses.
KW - Repair-welding
KW - High-strength steels
KW - X-ray diffraction
KW - Digital image correlation
KW - Residual stresses
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555672
DO - https://doi.org/10.1016/j.finmec.2022.100073
SN - 2666-3597
VL - 6
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
T1 - Abschlussbericht Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die Beschaffung und Verarbeitung von Werkstoffen für hochbelastete Komponenten sind meist kostenintensiv. Bestrebungen zur Kosten- und Ressourceneffizienz führen zu komplexeren Strukturen bzw. Konturen, sodass additive Fertigungsschritte zur Bauteilreparatur und -fertigung deutliche ökonomische Vorteile bieten. Hierfür sind additive und abtragende Fertigungsschritte komplementär und gezielt aufeinander abzustimmen, um beanspruchungsgerechte Funktionsflächen herzustellen. Hinsichtlich Inhomogenität und Anisotropie der Gefüge und Eigenschaften sowie fertigungsbedingter Beanspruchungen sind für den wirtschaftlichen Einsatz bei KMU, gerade für drahtbasierte Fertigungsverfahren und Wechselwirkungen nachfolgender Zerspanung dieser schwer spanbaren Werkstoffe noch viele Kenntnisse notwendig. Deshalb sind Untersuchungen zu diesen Einflüssen und Wechselwirkungen unter Nutzung innovativer Ansätze durchgeführt worden. Mit typischen kostenintensiven Ni- und Co-Cr-Legierungen wurden additive Bauteile, Auftrag- und Reparaturschweißungen hergestellt und Schweißzusätze für das PTA-Verfahren modifiziert, um die Erstarrungsmorphologie und das Eigenschaftsprofil zu optimieren. Die Übertragung auf MSG-Verfahren sicherte einen breiten industriellen Einsatz für hohe Auftragraten ab. Dies geschah mithilfe von modifizierten Fülldrähten sowie beschichteten Massivdrähten. Die wirtschaftliche spanende Bearbeitbarkeit wurde mit Zerspanbarkeitsanalysen für Schlichtfräsen und vergleichend für ultraschallunterstütze Fräsprozesse sichergestellt. Instrumentierte Experimente und Werkstoffanalytik hinsichtlich der Einflüsse auf Schmelzbad, Gefüge und Ausscheidungen sowie auf Randzoneneigenschaften und Eigenspannungen ermöglichten umfassende Erkenntnisse zur kombinierten additiven und abtragenden Fertigung. Dabei hat sich herausgestellt, dass eine Modifikation der Schweißzusatzwerkstoffe eine Homogenisierung der Mikrostruktur bedingt, welche wiederum den Zerspanprozess stabilisiert und letztendlich zu reduzierten Zerspankräften führt. Ferner wurde festgestellt, dass der ultraschallunterstützte Fräsprozess im Vergleich zum konventionellen Fräsprozess eine signifikante Reduzierung der Zerspankraft sowie eine höhere Oberflächenintegrität bedingt. Insbesondere die Induzierung oberflächennaher Druckeigenspannungen ist dabei hervorzuheben. Durch Bauteilversuche und -prüfungen, erfolgreiche Übertragbarkeitsstudien weiterer innovativer Werkstoffe verbunden mit Handlungsempfehlungen und der Zusammenarbeit mit den jeweiligen Normungsgremien, profitieren KMU von einer hochwirtschaftlichen Herstellung und Reparatur kostenintensiver Komponenten.
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
KW - Metallschutzgasschweißen
PY - 2023
SN - 978-3-96870-578-1
VL - 578
SP - 1
EP - 142
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-60796
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
A1 - Ulbricht, Alexander
A1 - Evans, Alexander
A1 - Altenburg, Simon
A1 - Ehlers, Henrik
A1 - Hilgenberg, Kai
A1 - Mohr, Gunther
T1 - Monitoring additive manufacturing processes by using NDT methods
N2 - In this presentation we discuss the online monitoring of metallic AM parts produced by the Laser Powder Bed Fusion (LPBF) process by using optical, thermographic and electromagnetic methods. In a first approach we present the detection of defects generated during the process and discuss how to improve these methods for the optimization of design and production of metallic AM parts.
T2 - ABENDI - Workshop
CY - Online meeting
DA - 19.11.2020
KW - Additive Fertigung
PY - 2020
AN - OPUS4-52042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Defect prediction on the Base of Thermographic features in Laser Powder Bed Fusion Utilizing Machine Learning Algorithms
N2 - Avoiding the formation of defects such as keyhole pores is a major challenge for the production of metal parts by Laser Powder Bed Fusion (LPBF). The use of in-situ monitoring by thermographic cameras is a promising approach to detect defects, however the data is hard to analyze by conventional algorithms. Therefore, we investigate the use of Machine Learning (ML) in this study, as it is a suitable tool to model complex processes with many influencing factors. A ML model for defect prediction is created based on features extracted from process thermograms. The porosity information calculated from an x-ray Micro Computed Tomography (µCT) scan is used as reference. Physical characteristics of the keyhole pore formation are incorporated into the model to increase the prediction accuracy. Based on the prediction result, the quality of the input data is inferred and future demands on in-situ monitoring of LPBF processes are derived.
T2 - Additive Manufacturing Benchmarks 2022
CY - Bethesda, MA, USA
DA - 14.08.2022
KW - Laser Powder Bed Fusion
KW - Thermography
KW - In-situ Monitoring
KW - Machine Learning
KW - Defect prediction
PY - 2022
AN - OPUS4-55591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Investigation of the thermal history of L-PBF metal parts by feature extraction from in-situ SWIR thermography
N2 - Laser powder bed fusion is used to create near net shape metal parts with a high degree of freedom in geometry design. When it comes to the production of safety critical components, a strict quality assurance is mandatory. An alternative to cost-intensive non-destructive testing of the produced parts is the utilization of in-situ process monitoring techniques. The formation of defects is linked to deviations of the local thermal history of the part from standard conditions. Therefore, one of the most promising monitoring techniques in additive manufacturing is thermography. In this study, features extracted from thermographic data are utilized to investigate the thermal history of cylindrical metal parts. The influence of process parameters, part geometry and scan strategy on the local heat distribution and on the resulting part porosity are presented. The suitability of the extracted features for in-situ process monitoring is discussed.
T2 - Thermosense: Thermal Infrared Applications XLIII
CY - Online meeting
DA - 12.04.2021
KW - SWIR camera
KW - Additive manufacturing (AM)
KW - Selective laser melting (SLM)
KW - Laser beam melting (LBM)
KW - In-situ monitoring
KW - Infrared thermography
PY - 2021
UR - https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11743/117430C/Investigation-of-the-thermal-history-of-L-PBF-metal-parts/10.1117/12.2587913.short?SSO=1&tab=ArticleLink
AN - OPUS4-52540
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oster, Simon
T1 - Defect prediction in laser powder bed fusion based on thermographic features utilizing convolutional neural networks
N2 - The appearance of irregularities such as keyhole porosity is a major challenge for the production of metal parts by laser powder bed fusion (PBF-LB/M). The utilization of thermographic in-situ monitoring is a promising approach to extract the thermal history which is closely related to the formation of irregularities. In this study, we investigate the utilization of convolutional neural networks to predict keyhole porosity based on thermographic features. Here, the porosity information calculated from an x-ray micro computed tomography scan is used as reference. Feature engineering is performed to enable the model to learn the complex physical characteristics of the porosity formation. The model is examined with regard to the choice of hyperparameters, the significance of thermal features and characteristics of the data acquisition. Based on the results, future demands on irregularity prediction in PBF-LB/M are derived.
T2 - GIMC SIMAI YOUNG 2022
CY - Pavia, Italy
DA - 29.09.2022
KW - Laser Powder Bed Fusion
KW - Thermography
KW - In-situ Monitoring
KW - Convolutional Neural Networks
PY - 2022
AN - OPUS4-56331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Thermography in laser powder bed fusion of metals: time over threshold as feasible feature in thermographic data
N2 - Thermography is one on the most promising techniques for in-situ monitoring for metal additive manufacturing processes. The high process dynamics and the strong focus of the laser beam cause a very complex thermal history within the produced specimens, such as multiple heating cycles within single layer expositions. This complicates data interpretation, e.g., in terms of cooling rates. A quantity that is easily calculated is the time a specific area of the specimen is at a temperature above a chosen threshold value (TOT). Here, we discuss variations occurring in time-over-threshold-maps during manufacturing of a defect free cuboid specimen.
T2 - 15th Quantitative InfraRed Thermography conference
CY - Online meeting
DA - 21.09.2020
KW - Additive Manufacturing
KW - Process monitoring
KW - Thermography
KW - L-PBF
KW - Time over threshold
PY - 2020
AN - OPUS4-51630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
T1 - Parameters and challenges for reliable hydrogen determination in welded joints by carrier gas hot extraction
N2 - For the hydrogen-based energy economy of tomorrow, the construction of the necessary infrastructure will play a central role. Most materials used to date, such as welded steels, can be prone to hydrogen embrittlement under certain conditions. This includes the classic delayed cold cracking during welding as well as degradation phenomena during service of components in hydrogen-containing environment. For the evaluation of any hydrogen effect, for example, on the mechanical properties of a welded metallic material, the hydrogen content must be precisely determined. In the case of weld seams, the carrier gas hot extraction (CGHE) according to ISO 3690 is meanwhile state-of-the-art. CGHE is based on accelerated hydrogen degassing due to the thermal activation of hydrogen at elevated temperatures. In addition to the quantification of hydrogen, thermal desorption analysis (TDA) with varying heating rates can be used to determine and evaluate the hydrogen trapping at microstructural defects in the material. For both techniques, experimental and metrological influences must be considered, which have a major effect on the result. For example, ISO 3690 suggests different sample geometries and minimum extraction times for CGHE. This study summarizes the results and experiences of numerous investigations at the Federal Institute for Materials Research and Testing (BAM) with different sample temperatures and geometries (ISO 3690 type B and cylindrical TDA samples) regarding the influence of the sample surface (polished/welded), measurement accuracy depending on the sample volume and the insufficient monitoring of the effect of PI control on the extraction temperature. A deviating extraction temperature from the target temperature can significantly falsify the measurement results. Based on the results, methods are shown which allow the desired extraction temperature to be reached quickly without physically interfering with the measuring equipment. This serves to significantly improve the reliability of the hydrogen measurement through increased signal stability and accelerated hydrogen desorption. In general, an independent temperature measurement with dummy samples is recommended for the heating procedure of choice to exclude possible undesired temperature influences before the measurement. The methods described can be transferred directly to industrial applications
KW - Welding
KW - Hydrogen measurement
KW - ISO 3690
KW - Carrier gas hot extraction
PY - 2024
DO - https://doi.org/10.37434/tpwj2024.04.01
SN - 0957-798X
VL - 4
SP - 3
EP - 10
PB - International Association Welding
AN - OPUS4-60071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Eissel, A.
A1 - Treutler, K.
A1 - Wesling, V.
T1 - Alloy modification for additive manufactured Ni alloy components Part II: Effect on subsequent machining properties
N2 - Alloy 36 (1.3912) is an alloy with 36% nickel and 64% iron and is generally classified as a difficult-to-cut material. Increasingly complex structures and the optimization of resource efficiency are making additive manufacturing (AM) more and more attractive for the manufacture or repair of components. Subsequent machining of AM components is unavoidable for its final contour. By using modern, hybrid machining processes, e.g., ultrasonic-assisted milling (US), it is possible to improve the cutting situation regarding the resulting surface integrity as well as the cutting force. Part I deals with the influence of the alloying elements Ti, Zr, and Hf on the microstructure and the hardness of the initial alloy 36. Part II focusses on the effect of the alloy modifications and the ultrasonic assistance on machinability as well as on the surface integrity after finish-milling. The results show a highly significant influence of the ultrasonic assistance. The cutting force during the US is reduced by over 50% and the roughness of approx. 50% compared to conventional milling (CM) for all materials investigated. Moreover, the US causes a defect-free surface and induces near-surface compressive residual stresses. CM leads to a near-surface stress state of approx. 0 MPa.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - Alloy 36
KW - Ultrasonic-assisted milling
KW - Surface integrity
KW - Modification of structural morphology
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566609
DO - https://doi.org/10.1007/s40194-022-01438-7
SP - 1
EP - 8
PB - Springer
CY - Heidelberg
AN - OPUS4-56660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Fügetechnik in Wasserstofftechnologien: Prozesse und Perspektiven
N2 - Die Wasserstofftechnologien der näheren Zukunft erfordern sichere Komponenten. Die Füge- und Schweißtechnik ist hier von zentraler Bedeutung, insbesondere für die Transportinfrastruktur (wie Pipelines). Der vorliegende Vortrag gibt hierzu einen umfassenden Überblick, beginnend bei der Erzeugung, Speicherung über Transport und Nutzung. Zusätzlich wird die zunehmende Bedeutung der additiven Fertigung beleuchtet und ein kurzer Ausblick auf die aktuelle Normungsroadmap der Wasserstofftechnologien gegeben.
T2 - Weiterbildung für Schweißaufsichtspersonen (a.d. SLV Halle)
CY - Halle (a.d. Saale), Germany
DA - 30.11.2023
KW - Wasserstofftechnologien
KW - Fügetechnik
KW - Studie
KW - Pipelines
KW - Forschung
PY - 2023
AN - OPUS4-59005
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
A1 - Kromm, Arne
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Innovatives Instandsetzungsschweißen von Altstahl: Materialverhalten und Herausforderungen
N2 - Aus Gründen der Nachhaltigkeit und Wirtschaftlichkeit gibt es in der stahlverarbeiten-den Industrie einen Trend zum Bauen im Bestand, um kostenintensive Sperrungen oder Rückbau zu vermeiden. Schweißen wird dabei als wirtschaftliches Fügeverfahren im Zusammenhang mit Altstählen kaum genutzt, obwohl Nieten- und Schraubenverbindungen oft unwirtschaftlich sind. Für die Instandsetzung ist häufig beschädigtes Bestands-material durch neue Stähle zu ersetzen bzw. Alt-Neu-Stahl-Mischverbindungen herzu-stellen. Aufgrund der verschiedenen Herstellungsprozesse von Altstählen ist nicht jeder Stahl aus dem 20. Jahrhundert schweißgeeignet. Daher ist zunächst eine Schweißeignungsprüfung erforderlich. In den vorliegenden Untersuchungen wurden verschiedene Altstähle hinsichtlich ihres Schweißverhaltens mittels Dilatometrie analysiert. Ziel war es, eine Datenbasis aus Schweiß-Zustands-Zeit-Diagrammen und Simulationen der Wärmeeinflusszone zu erstellen, um praxisrelevante Schweißuntersuchungen ableiten zu können. Diese geben wesentlichen Aufschluss hinsichtlich ihres schweißmetallurgischen Verhaltens und ihrer Schweißeignung. Solche Grundlagen sind zur Entwicklung innovativer schweißtechnischer Konzepte zur beanspruchungsgerechten Instandsetzung bestehender Altstahl-Infrastruktur in Deutschland notwendig.
T2 - 6. Symposium Materialtechnik, 20. bis 21. Februar 2025
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - Altstahl
KW - Schweiß-ZTU Diagramme
KW - Instandsetzungsschweißen
KW - Schweißeignungsprüfung
KW - Dilatometrie
PY - 2025
SN - 978-3-8440-9961-4
DO - https://doi.org/10.21268/20250505-1
VL - 15
SP - 370
EP - 380
PB - Shaker Verlag GmbH
CY - Düren
AN - OPUS4-63377
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Reparaturschweißen von zukünftigen in Betrieb befindlichen Wasserstoff-Pipelines
N2 - Wasserstoff leistet als Energieträger der Zukunft einen entscheidenden Beitrag zur nachhaltigen Energieversorgung. Der Transport wird vorwiegend durch das europäische Ferngasleitungsnetz erfolgen. Bisherige Untersuchungen zeigen, dass bisher verwendete Rohrstähle grundsätzlich für den Wasserstofftransport geeignet sind. Diese Eignung ist nicht direkt auf Reparaturfragestellungen im Betrieb übertragbar, da Schweißungen aus technisch-ökonomischen Gründen oft unter fortwährendem Gasfluss durchgeführt werden. Ein im Erdgasnetz angewandtes Konzept ist das Anbohren druckführender Pipelines („Hot Tapping“). Dazu werden Zylinderhalbschalen zuerst durch Längs- und dann per Rohrrundnähten an die Pipeline geschweißt. Essenziell ist dabei die maßgeschneiderte Wärmeeinbringung, um das „Durchbrennen“ in die Pipeline zu vermeiden. Für zukünftige Wasserstoffpipelines liegt der Fokus u.a. auf dünnwandigen Leitungen. Im Gegensatz zu Erdgas, führen die beim Schweißen erreichten hohen Temperaturen an der Innenseite der Pipeline zu einer zusätzlichen Wasserstoffaufnahme in den Rohrstahl mit möglicher Materialdegradation. Zur praktischen Lösung der Fragestellung, sind internationale Aktivitäten im Gang. Diese umfassen bspw. die Möglichkeiten und Weiterentwicklung von realistischen Prüfkonzepten (u.a. durch maßstäbliche Bauteilversuche). Dazu untersucht die Bundesanstalt für Materialforschung und -prüfung (BAM) in einem DVGW-geförderten Kooperationsprojekt mit Gasnetzbetreibern, die Frage der Übertragbarkeit der Schweißkonzepte der Erdgastechnik auf zukünftiger Wasserstoffpipelines.
T2 - DVS BV-Berlin / BAM Gemeinschaftsveranstaltung: Know-How-Transfer in der Fügetechnik: Forschung - Bildung - Fertigung
CY - Berlin, Germany
DA - 08.11.2024
KW - Schweißen
KW - Wasserstoff
KW - Pipelines
KW - Hot-tapping
KW - Bauteilversuch
PY - 2024
AN - OPUS4-61589
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rhode, Michael
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
A1 - Czeskleba, Denis
T1 - Simulation of hydrogen distribution in submerged arc welded heavy plates as tool for evaluating cold cracking sensitivity for offshore structures
N2 - Foundation structures for offshore wind turbines are typically made of heavy plate struc-tural steels, such as S420ML, welded by submerged arc welding. Due to the welding process conditions, higher amounts of hydrogen can be introduced. In this context, large plate thicknesses result in long diffusion paths and a prolonged diffusion time for hydrogen at ambient temperature and possible delayed hydrogen-assisted cold cracking. As a result, hydrogen can accumulate in areas of high mechanical stress and strain. Due to the delayed diffusion, a minimum waiting time of up to 48 h must be observed before non-destructive testing can be performed. In addition, the assessment of possible cold crack locations is very complex. For this reason, a numerical model of a component-like weld test was developed to simulate the temperature field during welding and subsequent cooling. A hydrogen diffusion model based on the temporal-local temperature distribution was established. It was applied to simulate the change of hydrogen distribution as a function of temperature cycle during multi-layer welding and further for the entire waiting time interval ≤ 48 h. As a result, crack critical areas could be evaluated in terms of accu-mulated hydrogen. An advantage of the diffusion model is the simulation of a normalized concentration, i.e. between "0" (no hydrogen) and "1" (max. concentration), which can be scaled to experimentally determined hydrogen concentrations. Finally, selected results for increased real hydrogen ingress are presented, which confirm the relatively high crack resistance of the S420 submerged arc welded joint.
KW - Hydrogen assisted cracking
KW - Diffusion
KW - Numerical simulation
KW - Offshore steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632416
DO - https://doi.org/10.21268/20250507-6
SP - 1
EP - 12
PB - Technische Universität Clausthal
CY - Clausthal-Zellerfeld, Deutschland
AN - OPUS4-63241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
A1 - Hadick, C.
A1 - Schu, K.
T1 - Component test concept for evaluation of in-service welding on pressurized hydrogen pipelines
N2 - Hydrogen is set as the energy carrier of tomorrow and most countries will achieve large-scale hydrogen transport through the conversion of the natural gas (NG) grid and the construction of new pipelines. The interaction between hydrogen and the pipeline materials differs fundamentally from that of NG, as hydrogen is readily absorbed into the material. Considering the possible hydrogen embrittlement (HE), the compatibility of the pipeline materials (low-alloyed steels with a wide strength/thickness range) must be investigated. However, pipelines require intervention for maintenance, repair, or grid expansion with welding on/onto the pipelines while in service, i.e. the well-known "hot tapping" and "plugging" or “stoppling”. The challenges compared to NG can be broadly divided into the possible austenitization of the inner pipe material exposed to hydrogen and the welding itself. Both result in a significant increase in hydrogen solubility and could potentially pose challenges in terms of HE. Emphasis is placed on the word "could" because knowledge of "hot tapping" on hydrogen pipelines is scarce due a lack of service experience. To this end, this study proposes a concept for a component-like demonstrator with the objectives: (1) safe feasibility of "hot tapping" on pressurized model hydrogen pipeline sections, (2) facilitate ex-post sample extraction for the purpose of quantifying the absorbed hydrogen concentrations, and (3) ensure in-situ temperature measurement during welding to monitor the pipeline surface temperature. For safety reasons in the event of an unintentional "burn-through", a solid cylinder was inserted in the demonstrator to restrict the hydrogen gas volume to a small, pressurized layer. Reference pipeline surface temperature measurements were ensured on comparable, unpressurized geometries. The investigated range of welding conditions was investigated for representative material/thickness combinations (DN50 to DN200), suggesting the feasibility of the demonstrator for the determination of reliable in-service welding conditions for both installed and new pipelines for hydrogen service.
T2 - 20th Pipeline Technology Conference ptc2025
CY - Berlin, Germany
DA - 06.05.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Repair welding
KW - component test
PY - 2025
SP - 1
EP - 11
AN - OPUS4-63168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Component test concept for evaluation of in-service welding on pressurized hydrogen pipelines
N2 - Hydrogen is set as the energy carrier of tomorrow and most countries will achieve large-scale hydrogen transport through the conversion of the natural gas (NG) grid and the construction of new pipelines. The interaction between hydrogen and the pipeline materials differs fundamentally from that of NG, as hydrogen is readily absorbed into the material. Considering the possible hydrogen embrittlement (HE), the compatibility of the pipeline materials (low-alloyed steels with a wide strength/thickness range) must be investigated. However, pipelines require intervention for maintenance, repair, or grid expansion with welding on/onto the pipelines while in service, i.e. the well-known "hot tapping" and "plugging" or “stoppling”. The challenges compared to NG can be broadly divided into the possible austenitization of the inner pipe material exposed to hydrogen and the welding itself. Both result in a significant increase in hydrogen solubility and could potentially pose challenges in terms of HE. Emphasis is placed on the word "could" because knowledge of "hot tapping" on hydrogen pipelines is scarce due a lack of service experience. To this end, this study proposes a concept for a component-like demonstrator with the objectives: (1) safe feasibility of "hot tapping" on pressurized model hydrogen pipeline sections, (2) facilitate ex-post sample extraction for the purpose of quantifying the absorbed hydrogen concentrations, and (3) ensure in-situ temperature measurement during welding to monitor the pipeline surface temperature. For safety reasons in the event of an unintentional "burn-through", a solid cylinder was inserted in the demonstrator to restrict the hydrogen gas volume to a small, pressurized layer. Reference pipeline surface temperature measurements were ensured on comparable, unpressurized geometries. The investigated range of welding conditions was investigated for representative material/thickness combinations (DN50 to DN200), suggesting the feasibility of the demonstrator for the determination of reliable in-service welding conditions for both installed and new pipelines for hydrogen service.
T2 - 20th Pipeline Technology Conference ptc2025
CY - Berlin, Germany
DA - 06.05.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Repair welding
KW - Component test
PY - 2025
AN - OPUS4-63170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Mikrostrukturspezifische Wasserstoffdiffusion in UP-Schweißverbindungen hochfester Stahlgrobbleche
N2 - Hochfeste Baustähle sind für den sogenannten, modernen Stahlleichtbau im Gebäude-, Anlagen- oder Mobilkranbau nicht mehr wegzudenken. Durch den Einsatz dieser Stähle mit Streckgrenzen ≥ 690 MPa können durch die Reduzierung der Wanddicke kann eine erhebliche konstruktive Gewichtsreduzierung erreicht werden. Dies führt zudem zu weiteren sekundären Vorteilen, wie geringeren Schweißverarbeitungskosten, da u.a. die zu füllenden Nahtquerschnitte kleiner sind. Für hochfeste Grobbleche kommt dabei insbesondere das Unterpulverschweißen (UP) zum Einsatz, das durch seine hohe Abschmelzleistung gekennzeichnet ist. Allerdings haben hochfeste Stahlgrobbleche aufgrund ihrer Mikrostruktur eine von vornherein begrenzte Duktilität ggü. niederfesten Stählen und sind per se anfälliger für verzögerte, wasserstoffunterstützte Kaltrissbildung Zudem führt die große Bleckdicke einerseits zu hoher konstruktiver Steifigkeit der Komponenten (mit der Folge erhöhter Eigenspannungen) und andererseits durch die dicken Schweißlagen zu langen Diffusionswege für den Wasserstoff, welcher bspw. durch feuchtes Schweißpulver in die Naht gelangen kann. Hieraus ergeben sich zwei Schwierigkeiten: (1) bis zu welcher Zeit mit einer verzögerten Rissbildung bei Raumtemperatur zu rechnen, wenn keine weitere Wärmebehandlung zur Reduktion des Wasserstoffes erfolgt bzw. (2) wenn diese notwendig ist, bei welche Temperatur dies erfolgen sollte. Dazu sind abgesicherte Diffusionskoeffizienten für den Wasserstoff in UP-Schweißungen notwendig, u.a. für numerische Simulationen. Diese Koeffizienten sind bisher nur äußert lückenhaft verfügbar. Aus diesem Grund wurden mikrostrukturspezifische, elektrochemische Permeationsversuche (nach ISO 17081) und Warmauslagerungsversuche mit TGHE an UP-Schweißverbindungen durchgeführt. Dazu wurden ein thermomechanisch (TM) gewalzter bzw. vergüteter (QT) Grundwerkstoff betrachtet, sowie das Schweißgut und die Wärmeeinflusszone (WEZ). Interessanterweise (und im Gegensatz zu Effekten des Wärmebehandlungszustandes auf die Diffusion in MSG-Schweißverbindungen) zeigten die UP-Schweißmikrostrukturen kaum signifikante Unter-schiede im Diffusionsverhalten von WEZ und Schweißgut. Dies ist auf den positiven Ef-fekt des mehrfachen Anlassens der Mikrostruktur durch die Mehrlagenschweißung zu-rückzuführen. Aus praktischer Anwendersicht können daher dickwandige UP-Verbindungen ausschließlich anhand der einfach ermittelbaren Diffusionskoeffizienten für den Grundwerkstoff beurteilt werden. Zudem zeigte sich, dass der Walzzustand (QT vs. TM) in Grobblechen gegenüber Dünnblechen eine untergeordnete Rolle für die Wasserstoffdiffusion bildet. Ergänzende numerische Simulationen zeitabhängigen Wasserstoffdiffusion bestätigten das Verhalten.
T2 - DGM Arbeitskreis Wasserstoff
CY - Neu-Isenburg, Germany
DA - 26.05.2025
KW - Wasserstoff
KW - Kaltrissbildung
KW - Diffusion
KW - Numerische Simulation
KW - Permeation
PY - 2025
AN - OPUS4-63235
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Quantification of hydrogen uptake during in-service hydrogen pipeline welding
N2 - Hydrogen must be transported on a large scale from producers to consumers to ensure the energy transition. The necessary pipeline grid is achieved by conversion of the natural gas (NG) grid and building new pipelines. Welding during service as part e.g. of “hot-tapping” is unavoidable for maintenance/repair/expansion. Based on existing studies, the basic material compatibility of (low-alloyed) pipeline steels with hydrogen is postulated. However, this cannot be assumed for the case of in-service welding on pipelines in pressurized condition. The reason is the increased temperature e.g. by preheating and (in particular) during welding of the single passes. As a result, the inner pipeline surface undergoes multiple short-term heating but to high temperatures. In particular, the first passes can result in a temperature close to the austenitic transformation of the material for small wall thicknesses. Both increase the hydrogen uptake into the welded joint. If hydrogen embrittlement is likely to occur, depends on the hydrogen uptake, which must be quantified. For this purpose, welding experiments on pressurized demonstrators were conducted. The hydrogen uptake at 100 bar was compared to reference experiments with nitrogen. A new sample extraction routine for the quantification of the weld-zone specific hydrogen uptake was established. Comprehensive experiments with different steels (P235, L360, L485), wall thicknesses (4.1 mm to 7.8 mm) and diameters (DN50 and DN200) were conducted. In addition, the influence of the welding layer sequence on the hydrogen uptake between single- and multi-layer welds was investigated. Analytical approaches were used to approximate the hydrogen uptake in the respective weld zones. The main findings were that the layer sequence and especially the wall thickness have a large influence on the hydrogen uptake.
T2 - 20th Pipeline Technology Conference ptc2025
CY - Berlin, Germany
DA - 06.05.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Repair welding
KW - Component test
PY - 2025
AN - OPUS4-63165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Ernst, W.
A1 - Spindler, H.
A1 - Kannengießer, Thomas
T1 - Hydrogen-assisted cracking of GMA welded 960 MPa grade high-strength steels
N2 - High-strength steels with yield strength of 960 MPa are susceptible to hydrogen-assisted cracking (HAC) during welding processing. In the present paper, the implant test is used to study HAC in a quenched and tempered steel S960QL and a high-strength steel produced by thermo-mechanical controlled process S960MC. Welding is performed using the gas metal arc welding process. Furthermore, diffusible hydrogen concentration (HD) in arc weld metal is determined. Based on the implant test results, lower critical stress (LCS) for complete fracture, critical implant stress for crack initiation, and embrittlement index (EI) are determined. At HD of 1.66 ml/100 g, LCS is 605 MPa and 817 MPa for S960QL and S960MC, respectively. EI is 0.30 and 0.46 for S960QL and S960MC, respectively. Fracture surfaces of S960QL show higher degradation with reduced deformation. Both, higher EI of S960MC and fractography show better resistance to HAC in the HAZ of S960MC compared to S960QL.
KW - High-strength steel
KW - Welding
KW - Diffusible hydrogen
KW - Hydrogen-assisted cracking
KW - Heat-affected zone
KW - Implant test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510307
DO - https://doi.org/10.1016/j.ijhydene.2020.05.077
SN - 0360-3199
VL - 45
IS - 38
SP - 20080
EP - 20093
PB - Elsevier Ltd
CY - Amsterdam, NL
AN - OPUS4-51030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thomas, Maximilian
A1 - Vollert, F.
A1 - Weidemann, Jens
A1 - Gibmeier, J.
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals
N2 - The subject of this study is how, and to what extent, Varestraint/Transvarestraint test results are influenced by both testing parameters and characteristics of evaluation methods. Several different high-alloyed martensitic LTT (low Transformation temperature) filler materials, CrNi and CrMn type, were selected for examination due to their rather distinctive solidification cracking behaviour, which aroused interest after previous studies. First, the effects of different process parameter sets on the solidification cracking response were measured using standard approaches. Subsequently, microfocus X-ray computer tomography (μCT) scans were performed on the specimens. The results consistently show sub-surface cracking to significant yet varying extents. Different primary solidification types were found using wavelength dispersive X-ray (WDX) analysis conducted on filler metals with varying Cr/Ni equivalent ratios. This aspect is regarded as the main difference between the CrNiand CrMn-type materials in matters of cracking characteristics. Results show that when it comes to testing of modern highperformance alloys, one set of standard Varestraint testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account.
KW - Solidification cracking
KW - Varestraint testing
KW - MVT
KW - LTT filler metal
KW - Microfocus X-ray computer tomography (μCT)
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506039
DO - https://doi.org/10.1007/s40194-020-00895-2
VL - 64
SP - 913
EP - 923
PB - Springer Nature
CY - Heidelberg, New York
AN - OPUS4-50603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part II - Mechanisms of stress relief cracking during post weld heat treatment
N2 - Welding of 13CrMoV9-10 vanadium steel requires care due to an increased susceptibility to stress relief cracking during post weld heat treatment. Previous research into the crack formation in creep-resistant steels has focused on thermal and metallurgical factors; however, little knowledge has been gathered regarding the crack formation during post weld heat treatment considering real-life restraint conditions. This work is subdivided in two parts. Part I showed that an increasing heat input during submerged arc welding under restraint led to an increasing stress level in the joint prior to the post weld heat treatment. The magnitude of stress relief cracking observed in the heat-affected zone after the post weld heat treatment is affected by the heat input. In Part II of this work, the cracks and the associated microstructure which occurred under restraint were studied. The application of a Special acoustic emission analysis indicated that the cracks formed in a temperature range between 300 and 500 °C during the post weld heat treatment. The toughness in the heat-affected zone of the restrained welds was affected by the welding heat input.
Microstructural analyses of all specimens revealed accelerated aging due to precipitation of carbides during post weld heat treatment under restraint.
KW - Welding
KW - Creep-resistant steel
KW - Post weld heat treatment
KW - Stress relief cracking
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506283
DO - https://doi.org/10.1007/s40194-020-00881-8
SN - 1878-6669
VL - 64
SP - 819
EP - 829
PB - Springer
CY - Berlin
AN - OPUS4-50628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part I - Effect of heat control on welding stresses and stress relief cracking
N2 - The avoidance of failures during the fabrication or operation of petrochemical reactors made of creep-resistant, low-alloy steels as 13CrMoV9-10 requires still research despite over 60 years of international investigations in the field of stress relief cracking. The quality of modern base materials and filler metals leads to the fact that previously known crack causes, such as impurities of S or P, recede into the background. Rather, the causes are increasingly to be found in the fabrication process. Investigations on the influence of heat control on the stresses in welded components and thus on the stress relief cracking sensitivity under realistic manufacturing conditions are not yet available. This work is subdivided in two parts. Part 1 of this study focused on the effect of heat control during submerged arc welding on the stresses. For this purpose, a testing facility was applied, which allows to observe the forces and moments accumulating during welding or heat treatment in a component-like specimen under shrinkage restraint. The stress acting in the specimen increases with higher preheat/interpass temperatures and higher heat input. During the heat treatment, the stresses are relieved. Nevertheless, cracks are formed already during heating. The total crack length correlates with the heat input.
KW - Welding
KW - Creep-resistant steel
KW - Post weld heat treatment
KW - Stress relief cracking
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506271
DO - https://doi.org/10.1007/s40194-020-00875-6
SN - 1878-6669
VL - 64
IS - 5
SP - 807
EP - 817
PB - Springer
CY - Berlin
AN - OPUS4-50627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Börner, Andreas
T1 - Rührreibschweißen von Hoch- und Mittelentropie-Legierungen
N2 - Hoch- und Mittelentropie-Legierungen (engl. High/Medium Entropy Alloys–HEA/MEA) sind relativ neue Werkstoffklassen. Im Gegensatz zu herkömmlichen Le-gierungen bestehen HEA aus fünf bzw. MEA aus drei oder vier Legierungselementen im äquiatomaren Gleichgewicht. Viele HEA weisen aufgrund hervorragender struktu-reller Eigenschaftskombinationen von sehr tiefen bis zu hohen Temperaturen enor-mes Anwendungspotential auf. Die Anwendung für reale Bauteile stellt jedoch die zentrale Frage der Eignung für die fügetechnische Verarbeitung. Dieser Aspekt findet in der weltweiten Materialforschung bisher kaum Beachtung. Anforderungen an die zuverlässige und sichere fügetechnische Verarbeitung dieser Werkstoffe sind von wesentlicher Bedeutung hinsichtlich wirtschaftlicher Bauteilfertigung für spätere po-tenzielle Anwendungsbereiche, bspw. in der Energietechnik. Das Rührreibschweißen (engl. Friction Stir Welding–FSW) stellt hierbei einen vielversprechenden Fügepro-zess dar, dessen Hauptvorteil in der Schweißprozesstemperatur unterhalb der Schmelztemperatur der zu fügenden Werkstoffe liegt. Dies bedingt die Vermeidung der Ausbildung von harten, versprödenden intermetallischen Phasen, wie sie z. B. beim konventionellen Schmelzschweißen von Eisen-Aluminium-Verbindungen auf-treten. Die vorliegende Arbeit stellt grundlegende Untersuchungen zur Schweißbar-keit einer CoCrFeMnNi-Legierung (HEA) und einer CoCrNi-Legierung (MEA) mit dem FSW-Prozess vor. Die Versuchsschweißungen werden mittels mikroskopischer Analysen hinsichtlich des Schweißnahtaufbaus sowie Schweißnahtfehlern charakte-risiert. FSW zeigt sich als grundlegend geeignet zur Verbindungsschweißung der HEA bzw. MEA. Anhand dieser Ergebnisse kann eine weitere Bewertung der Schweißbar-keit erfolgen.
T2 - 4 Niedersächsisches Symposium Materialtechnik Clausthal
CY - Online meeting
DA - 25.02.2021
KW - Hochentropie Legierung
KW - Rührreibschweißen
KW - Mediumentropie Legierung
PY - 2021
SP - 502
EP - 511
AN - OPUS4-52255
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Thickness and microstructure effect on hydrogen diffusion in creep-resistant 9 % Cr P92 steel and P91 weld metal
N2 - Martensitic 9 %-Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. The small number of available diffusion coefficients varies already at room temperature by several orders of magnitude (mostly regarded as result of present microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. The diffusion coefficients are calculated by two methods (time-lag and inflection point method) were performed. The results show that, despite of microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients.
T2 - IIW Intermediate Meeting, Comm. IX-C "Welding of creep and heat-resistant materials"
CY - Online meeting
DA - 08.03.2021
KW - Hydrogen
KW - Welding
KW - Diffusion
KW - Creep-resistant steel
KW - Electrochemical permeation
PY - 2021
AN - OPUS4-52239
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Untersuchungen zur Verarbeitung von Hochentropielegierungen
N2 - Es werden Untersuchungsmethoden und erste Ergebnisse zur Verarbeitbarkeit von Hochentropielegierungen aufgezeigt.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Online meeting
DA - 20.01.2021
KW - Hochentropie Legierung
KW - Rührreibschweißen
KW - Zerspanung
PY - 2021
AN - OPUS4-52258
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Safarov, J.
A1 - Abdullayeva, G.
A1 - Bashirov, M.
A1 - Tuma, Dirk
A1 - Bashirov, R.
T1 - The ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate revisited: Solubility of carbon dioxide over an extended range of temperature and pressure
N2 - Solubility data of carbon dioxide (CO2) in the ionic liquid 1-ethyl-3-methylimidazolium methanesulfonate [EMIM][CH3SO3] at T= (273.15 to 413.15) K and pressures up to p= 5.0 MPa are reported. The solubility measurements were carried out using an isochoric method which operates in decrements of ΔT = 20 K within the investigated temperature range and at selected four different pressure steps ranging froma pressure p of around 5.0 MPa down to around 0.4 MPa. The solubility of CO2 in the ionic liquid monotonously decreases with increasing temperatures at a constant pressure. Within the p,T-range investigated, CO2 displayed a solubility in [EMIM] [CH3SO3] from a mole fraction x= 0.0160 mol·mol−1 and a corresponding molality m = 0.0791 mol·kg−1 at T = 413.15 K and p =0.432 MPa up to x = 0.4049 mol·mol−1 and m = 3.2982 mol·kg−1 at T = 293.15 K and p = 4.577 MPa. Henry's law constant was calculated from the solubility data reported here, and literature data were reviewed for comparison. Additionally, thermodynamic state properties that can be derived from Henry's law constant, such as the Gibbs energy of solvation ΔsolG, the enthalpy of solvation ΔsolH, the entropy of solvation ΔsolS, and the heat capacity of solvation ΔsolCp, were calculated.
KW - Hydrophilic ionic liquid
KW - Carbon dioxide
KW - High-pressure solubility
PY - 2021
DO - https://doi.org/10.1016/j.molliq.2021.115920
SN - 0167-7322
VL - 333
SP - 115920
PB - Elsevier B. V.
CY - Amsterdam
AN - OPUS4-52436
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wagner, Adrian
T1 - Ergebnisse der 2. Probenentnahme im Rahmen des Forschungsprojekt es zur Auslagerung von Edel und Duplexstählen in Straßentunneln
N2 - Aufgrund der stark korrosiven Atmosphäre in Tunnelbauwerken kommt es aufgrund von Reinigungs- und Sanierungsmaßnahmen an Ein- und Anbauteilen aus nichtrostendem Stahl häufig zu wartungsbedingten Verkehrsbeeinflussungen und Tunnelsperrungen. Bislang ist nur eine kleine Gruppe rostfreier Edelstähle für die Verwendung in Tunnelbauwerken zugelassen. Im Sinne einer mittel- bis langfristigen Reduktion von Wartungsarbeiten besteht jedoch großes Interesse, die Einsatzmöglichkeiten alternativer nichtrostender Stähle zu erhöhen. Ziel ist die Qualifizierung ferritischer-austenitischer Stähle.
Erste Untersuchungen nach 2 Jahren Auslagerung zeigten bisher vielversprechende Ergebnisse.
T2 - Vorstellung der Ergebnisse bei VDEh in Düsseldorf
CY - Online meeting
DA - 11.08.2020
KW - Duplex
KW - Tunnelbauwerke
KW - Korrosion
PY - 2020
AN - OPUS4-51109
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - In situ heat accumulation by geometrical features obstructing heat flux and by reduced inter layer times in laser powder bed fusion of AISI 316L stainless steel
N2 - Material qualification for laser powder bed fusion (L-PBF) processes are often based on results derived from additively manufactured (AM) bulk material or small density cubes, although it is well known that the part geometry has a tremendous influence on the heat flux and, therefore, on the thermal history of an AM component. This study shows experimentally the effect of simple geometrical obstructions to the heat flux on cooling behavior and solidification conditions of 316L stainless steel processed by L-PBF. Additionally, it respects two distinct inter layer times (ILT) as well as the build height of the parts. The cooling behavior of the parts is in-situ traced by infrared (IR) thermography during the built-up. The IR signals reveal significant differences in cooling conditions, which are correlated to differences in melt pool geometries. The acquired data and results can be used for validation of computational models and improvements of quality assurance.
T2 - 11th CIRP Conference on Photonic Technologies (LANE 2020)
CY - Online meeting
DA - 07.09.2020
KW - Additive Manufacturing
PY - 2020
AN - OPUS4-51255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Der Einfluss moderner Bearbeitungsverfahren auf die Oberflächenintegrität von Hoch- und Medium-Entropie-Legierungen
N2 - High Entropy Alloys (HEAs) are a recent class of materials. In contrast to conventional alloys, HEAs consist of five alloying elements in equiatomic equilibrium. The high entropy effect is due, among other things, to the increased configuration entropy, which promotes solid solution formation. Many HEAs have enormous application potential due to excellent structural property combinations from very low to high temperatures. For the introduction of HEAs in real components, however, the question of the applicability of machining production technologies for component manufacture is of central importance. This has so far received Little attention in global materials research. Reliable and safe processing is essential for the demand of economical component production for potential areas of application, e.g. in power plant technology.
For metals, milling is the standard machining process. This article presents the results of machining analyses. It focuses on the surface integrity resulting from the milling process on a Co20Cr20Fe20Mn20Ni20-HEA. For this purpose, investigations were carried out using ball nose end milling tools for conventional milling process in comparison to an innovative hybrid process available at BAM Berlin, Ultrasonic-Assisted Milling (USAM). USAM promises a lower Degradation of the surface properties due to lower loads on the workpiece surface during machining.
For this purpose, basic milling parameters (cutting speed and tooth feed) were systematically varied and cutting forces were measured during the milling experiments. The subsequent Analysis of these forces allows an understanding of the mechanical loads acting on the tool and component surface. These loads cause topographical, mechanical and microstructural influences on the surface and consequently on the surface integrity. For their characterization, light and scanning electron microscopy were used, and the roughness and residual stresses via X-ray diffraction were measured. The results indicate significant advantages using USAM, especially due to reduced cutting forces compared to the conventional milling process. This causes lower mechanical loads on the tool and surface, combined with lower tensile residual stresses on and below the surface, and ultimately results in a significantly enhanced surface integrity.
N2 - Hochentropie Legierungen (engl. High Entropy Alloys, HEAs) sind eine relativ neue Werkstoffklasse. Seit ersten Veröffentlichungen im Jahr 2004, steigt das Forschungsinteresse an diesem Werkstoffkonzept stetig an. Im Gegensatz zu herkömmlichen Legierungen bestehen HEAs aus fünf Legierungselementen in äquiatomaren Gleichgewicht. Der Hochentropie-Effekt ist dabei u.a. auf die erhöhte Konfigurationsentropie zurückzuführen, der die Mischkristallbildung fördert. Viele HEAs weisen aufgrund hervorragender struktureller Eigenschaftskombinationen von sehr tiefen bis zu hohen Temperaturen enormes Anwendungspotential auf. Für ihre Anwendung als reale Bauteile stellt sich aber die zentrale Frage der Anwendbarkeit von trennenden Fertigungstechnologien für HEAs. Dies findet in der bisherigen weltweiten Materialforschung bisher kaum Beachtung. Für die Forderung nach wirtschaftlicher Bauteilfertigung ist für potenzielle Anwendungsbereiche, bspw. in der Energietechnik, eine zuverlässige und sichere Verarbeitung von wesentlicher Bedeutung. Fräsen ist dabei ein Standardprozess für die zerspanende Bearbeitung von Metallen. Der vorliegende Beitrag stellt Ergebnisse durchgeführter Zerspanbarkeitsanalysen vor. Diese konzentriert sich auf die aus dem Fräsprozesse resultierende Oberflächenintegrität an einem sogenannten „Cantor-HEA“ (mit der Zusammensetzung Co20Cr20Fe20Mn20Ni20). Hierfür wurden Untersuchungen mit konventionellem Kugelkopffräsen durchgeführt und mit dem an der BAM Berlin verfügbaren innovativen Hybridverfahren, dem ultraschallunterstützten Fräsen (engl. Ultrasonic Assisted Milling, USAM), verglichen. USAM verspricht dabei eine geringere Degradation der Oberflächeneigenschaften aufgrund geringerer Belastungen auf die Werkstückoberfläche beim Spanen. Dazu wurden grundlegende Fräsparameter (Schnittgeschwindigkeit und Zahnvorschub) systematisch variiert und während der Fräsexperimente die Zerspankräfte gemessen, deren anschließende Analyse ein Verständnis für die mechanischen Beanspruchungen ermöglicht, die auf Werkzeug und Bauteiloberfläche wirken. Diese Beanspruchungen bedingen eine topographische, mechanische und mikrostrukturelle Beeinflussung der Oberfläche und letztlich der Oberflächenintegrität. Zur deren Charakterisierung wurden Licht- und Rasterelektronen-mikroskopie eingesetzt, sowie die Rauheit mittels 3D-Mikroskop und die Eigenspannungen mittels Röntgendiffraktion gemessen. Die Ergebnisse belegen einen signifikanten den positiven Effekt beim USAM, insbesondere durch reduzierte Zerspankräfte im Vergleich zum konventionellen Kugelkopffräsen. Dies führt zu geringerer mechanischer Beanspruchung von Werkzeug und Oberfläche verbunden mit geringeren Zugeigenspannungen an und unter der Oberfläche und bewirkt schließlich eine wesentlich höhere Oberflächenintegrität.
T2 - Symposium on Materials and Joining
CY - Magdeburg, Germany
DA - 07.09.2020
KW - High entropy alloy
KW - Machining
KW - Ultrasonic machining
PY - 2020
AN - OPUS4-51586
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Data-Driven Materials Science: Reproducibility and Standardization
N2 - Advancing development and digitalization in materials science requires to focus on quality assurance, interoperability, and compliance with FAIR principles. Semantic technologies offer effective solutions for these challenges by enabling the storage, processing, and contextualization of data in machine-actionable and human-readable formats – essential for robust data management.
This presentation highlights the PMD Core Ontology 3.0 (PMDco 3.0), developed specifically for the field of materials science and engineering, and its implementation within generic knowledge representation frameworks. Demonstrators such as standardized mechanical testing, material processing workflows, and the Orowan Demonstrator exemplify the ontology’s practical applications. The use of graph patterns, able to be compiled into rule-based semantic shapes, supports a unified and automated approach to managing heterogeneous experimental data across domains.
T2 - Persson Group Seminar
CY - Berkeley, CA, USA
DA - 23.06.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
KW - PMD Core Ontology
KW - Graph Patterns
PY - 2025
AN - OPUS4-63484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - García-González, M.
A1 - González-González, I.
A1 - García-García, I.
A1 - Blasón Gonzalez, Sergio
A1 - Lamela-Rey, M. J.
A1 - Fernández-Canteli, A.
A1 - Álvarez-Arenal, A.
T1 - Effect of abutment finish lines on the mechanical behavior and marginal fit of screw-retained implant crowns: An in vitro study
N2 - Statement of problem
The design of the implant-abutment connection has been widely researched, but the impact of different crown-abutment geometries remains unclear.
Purpose
The purpose of this in vitro study was to evaluate the effect of different crown-abutment margin geometries on the mechanical behavior and fit of screw-retained implant-supported single-crown restorations by using mechanical static and fatigue tests and mastication simulation.
Material and methods
A total of 45 cobalt-chromium premolar-shaped metal frameworks were fabricated for single-unit implant-supported screw-retained restorations on stock abutments and internal hexagon Ø4.25×11-mm cylindrical implants. They were divided into 3 groups according to margin geometry: S, shoulder; C, chamfer; and F, feather-edge. Three static load until fracture and 24 dynamic load tests were performed by using the International Organization for Standardization 14801:2016 standard (ISO 14801:2016) (number of cycles limit: 5×106 cycles, frequency: 6 Hz). The ProFatigue software program was used to optimize the procedure (S, n=12 specimens; C, n=7 specimens; and F, n=5 specimens). Six additional specimens from each group were subjected to a mastication simulation (limit number of cycles: 1×106 cycles, cyclic loading from Pmin=30 N to Pmax=300 N, frequency: 6 Hz). Results from the fatigue tests were reported descriptively, and the Fisher exact test was used to analyze the difference in failure modes. Data from maximum misfit were evaluated by photogrammetry and statistically analyzed with the Anderson-Darling test and the Kruskal-Wallis and Dunn multiple comparison tests (α=.05).
Results
The fatigue limit was 456 N for group S, 512 N for group C, and 514 N for group F. The mean ±standard deviation misfit was 2.6 ±0.1 μm for group S, 3.8 ±1.1 μm for group C, and 3.6 ±0.8 μm for group F. Differences in misfit between groups S and C and between groups S and F were statistically significant (P<.05).
Conclusions
Crown-abutment connections with chamfer and feather-edge margins showed better mechanical behavior, while shoulder margin exhibited better fit. However, high levels of fit were achieved for all the evaluated geometries.
KW - Photogrammetry
KW - Implant-supported prostheses
KW - Crown-abutment connection
KW - Margin design
KW - Static load
KW - Dynamic load
KW - Misfit
PY - 2022
DO - https://doi.org/10.1016/j.prosdent.2021.08.028
SN - 0022-3913
VL - 127
IS - 2
SP - 318.e1
EP - 318.e10
PB - Elsevier
AN - OPUS4-55238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khan, K.
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
A1 - De, A.
T1 - Probing a novel heat source model and adaptive remeshing technique to simulate laser powder bed fusion with experimental validation
N2 - A finite element method based three-dimensional heat transfer model with adaptive remeshing is presented to simulate the building of multiple tracks and layers in laser powder bed fusion of metallic powders with enhanced computational competence. A dimensional analysis is undertaken to define the heat source dimensions as function of laser parameters and properties of alloy powder. The computational model is used to calculate the melt pool cross sections for multiple combinations of laser power and scanning velocities considering multi-track-multi-layer builds of SS316L powder. The computed results are verified extensively with the corresponding experimentally measured ones. The model is utilized further to examine its ability to predict defects such as melt track discontinuity and incomplete fusion between neighboring tracks and layers. Overall, the adaptive remeshing and the proposed heat source expression could significantly enhance the model competence by reducing the computational time and memory while maintaining the accuracy of results in simulating laser powder bed fusion of multiple tracks and layers.
KW - Selective laser melting (SLM)
KW - Laser powder bed fusion (L-PBF)
KW - Adaptive remeshing
KW - SS316L alloy
KW - Pool dimensions
KW - Melt pool defects
PY - 2020
DO - https://doi.org/10.1016/j.commatsci.2020.109752
VL - 181
SP - 109752
PB - Elsevier B.
CY - Amsterdam
AN - OPUS4-50703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Friction stir welding of a CoCrFeMnNi high entropy alloy compared to AISI 304 austenitic stainless steel: evolution of microstructure and mechanical properties
N2 - High entropy alloys (HEA) are a new class of materials. In contrast to conventional alloys, HEA are single-phase alloys with at least five alloying elements. HEAs have enormous application potential due to (postulated) excellent structural property combinations from low to high temperatures. For HEA-application as structural materials in real components, a key issue is the suitability for joining processing. Requirements for the reliable and safe joining of these materials are crucial regarding economical component manufacture for future applications. In this context, friction stir welding (FSW) is a promising joining process due to the welding process temperature below the material melting point avoiding major issues, e. g. formation of (hard and brittle) intermetallic phases, which may have detrimental influences on the weld joint properties.
This study presents elementary research about the FSW process influences on a CoCrFeMnNi-HEA with focus on the microstructure and mechanical properties. For that purpose, the FSW joint of the HEA is compared to that of an austenitic stainless steel AISI 304. The microstructures of the welds were investigated and characterized by means of light microscopy, SEM, EBSD and XRD. Hardness and tensile testing were applied to determine influences on the mechanical properties. Generally, a comparable weldability of HEA and AISI 304 in terms of metallurgical characteristics and resulting mechanical properties exhibited. For the weld joints of both materials typical characteristics regarding FSW were observed within the weld metal and thermo-mechanically influenced zone: fine-grained stirred zone with increased hardness and reduced fracture elongation compared with the respective base material.
T2 - EUROMAT 2021
CY - Online meeting
DA - 13.09.2021
KW - High entropy alloy
KW - Friction stir welding
PY - 2021
AN - OPUS4-53308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Rührreib- und WIG-Schweißen der CoCrFeMnNi-HEA und CoCrNi-MEA
N2 - Hochentropielegierungen sind eine neue Materialklasse. Um diese in die als reale Bauteile zu in die Anwendung zu überführen muss die Verarbeitbarkeit ausführlich erforscht werden. In dieser Präsentation werden dafür erste Ergebnisse der schweißtechnischen Verarbeitung mittels Rührreib- und WIG-Schweißen dargestellt.
T2 - SURDIA Zwischenkolloquium
CY - Online meeting
DA - 25.06.2021
KW - Hochentropie Legierung
KW - Schweißen
KW - Mediumentropie Legierung
KW - Rührreibschweißen
KW - WIG-Schweißen
PY - 2021
AN - OPUS4-53312
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Schweißen von Hochentropielegierungen
N2 - Hochentropielegierungen sind deine relative neue Werkstoffklasse, mit ersten Veröffentlichungen von 2004. Seitdem wurden diese Legierungen weiterentwickelt um möglichst gute Eigenschaften zu erhalten. Um diese Eigenschaften auch für reale Bauteile genutzt zu werden, muss auch die Verarbeitbarkeit und deren Einfluss auf die Anwendungseigenschaften untersucht werden. Diese Präsentation fasst den aktuellen Stand der Forschung zusammen und ordnet erste eigene Untersuchungen in den aus der Literatur ein.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium der Otto-von-Guericke Universität Magdeburg
CY - Online meeting
DA - 23.06.2021
KW - Hochentropie Legierung
KW - Schweißen
PY - 2021
AN - OPUS4-53309
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Delgado Arroyo, Diego
T1 - Influence of machining parameters on the surface of high entropy alloys
N2 - High entropy alloys are a new class of materials. In order to transfer their use to real components, their machinability must be investigated. For this purpose, preliminary investigations were carried out on samples from the TU Chemnitz in order to apply for a joint project based on these investigations.
T2 - Kooperationsmeeting TU-Chemnitz
CY - Online meeting
DA - 01.06.2021
KW - High Entropy Alloy
KW - Ultrasonic assisted machining
PY - 2021
AN - OPUS4-53324
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Prozessinduzierte Vorerwärmung beim pulverbasierten Laserstrahlschmelzen und deren Auswirkung auf die Bauteileigenschaften austenitischer Stahlbauteile
N2 - Heterogene Fehlstellendichten und Mikrostrukturausbildungen sind große Heraus-forderungen für den Einsatz des pulverbettbasierten Laserstrahlschmelzens (L PBF) besonders für sicherheitskritische Bauteile. Unter der Vielzahl an Einflussfaktoren auf die Qualität und die mechanischen Eigenschaften von L PBF-Bauteilen hat die Zwischenlagenzeit (ILT) bisher wenig Beachtung gefunden. Sie nimmt ebenso wie die Bauteilgeometrie Einfluss auf die thermische Historie während der Fertigung. Ihr Einfluss auf die intrinsische Vorerwärmung ist in Kombination mit der Bauteilhöhe mittels thermografischer Temperaturmessung untersucht worden. Signifikante Unterschiede in der thermischen Historie konnten dabei mit variierenden Schmelzbaddimensionen, Korngrößen und Fehlstellendichten am Beispiel der austenitischen Stahllegierung AISI 316L in Zusammenhang gebracht werden.
T2 - DVM Tagung Additiv gefertigte Bauteile und Strukturen
CY - Berlin, Germany
DA - 03.11.2021
KW - Additive Manufacturing
KW - Laser powder bed fusion
KW - In-situ process monitoring
PY - 2021
AN - OPUS4-53729
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
ED - Eiber, M.
T1 - Prozessinduzierte Vorerwärmung beim pulverbettbasierten Laserstrahlschmelzen und deren Auswirkung auf die Bauteileigenschaften austenitischer Stahlbauteile
N2 - Heterogene Fehlstellendichten und Mikrostrukturausbildungen sind große Herausforderungen für den Einsatz des pulverbettbasierten Laserstrahlschmelzens (L PBF) besonders für sicherheitskritische Bauteile. Unter der Vielzahl an Einflussfaktoren auf die Qualität und die mechanischen Eigenschaften von L PBF-Bauteilen hat die Zwischenlagenzeit (ILT) bisher wenig Beachtung gefunden. Sie nimmt ebenso wie die Bauteilgeometrie Einfluss auf die thermische Historie während der Fertigung. Ihr Einfluss auf die intrinsische Vorerwärmung ist in Kombination mit der Bauteilhöhe mittels thermografischer Temperaturmessung untersucht worden. Signifikante Unterschiede in der thermischen Historie konnten dabei mit variierenden Schmelzbaddimensionen, Korngrößen und Fehlstellendichten am Beispiel der austenitischen Stahllegierung AISI 316L in Zusammenhang gebracht werden.
T2 - DVM 6. Tagung Additiv gefertigte Bauteile und Strukturen
CY - Berlin, Germany
DA - 03.11.2021
KW - Additive Fertigung
KW - Laserstrahlschmelzen
KW - In-situ Prozessüberwachung
KW - Wärmeakkumulation
KW - Zwischenlagenzeit
PY - 2021
DO - https://doi.org/10.48447/Add-2021-003
SP - 19
EP - 30
PB - Deutscher Verband für Materialforschung und -prüfung (DVM)
CY - Berlin
AN - OPUS4-54287
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - HEA Processing - SURDIA - Current R&D at BAM
N2 - This presentation summarizes the latest results on the BAM-Themenfeld project SURDIA on processing of high-entropy alloys (HEAs) at BAM. At first, the influence of machining by ultrasonic-assisted milling on the surface integrity is presented. Second, the weld processing by Tungsten Inert Gas (TIG) welding is presented and the results of the Friction Stir Welding (FSW), which is conducted at BAM for the first time.
T2 - DFG SSP 2006 - Subgroup meeting on the synthesis and processing of CCAs/HEAs
CY - Online meeting
DA - 08.10.2021
KW - High-entropy alloy
KW - Ultrasonic-assisted milling
KW - Welding
KW - Processing
KW - Surface integrity
PY - 2021
AN - OPUS4-53497
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monavari, M.
A1 - Homaeigohar, S.
A1 - Fuentes-Chandía, M.
A1 - Nawaz, Q.
A1 - Monavari, Mehran
A1 - Venkatraman, A.
A1 - Boccaccini, A.
T1 - 3D printing of alginate dialdehyde-gelatin (ADA-GEL) hydrogels incorporating phytotherapeutic icariin loaded mesoporous SiO2-CaO nanoparticles for bone tissue engineering
N2 - 3D printing enables a better control over the microstructure of bone restoring constructs, addresses the challenges seen in the preparation of patient-specific bone scaffolds, and overcomes the bottlenecks that can appear in delivering drugs/growth factors promoting bone regeneration. Here, 3D printing is employed for the fabrication of an osteogenic construct made of hydrogel nanocomposites. Alginate dialdehyde-gelatin (ADA-GEL) hydrogel is reinforced by the incorporation of bioactive glass nanoparticles, i.e. mesoporous silica-calcia nanoparticles (MSNs), in two types of drug (icariin) loading. The composites hydrogel is printed as superhydrated composite constructs in a grid structure. The MSNs not only improve the mechanical stiffness of the constructs but also induce formation of an apatite layer when the construct is immersed in simulated body fluid (SBF), thereby promoting cell adhesion and proliferation. The nanocomposite constructs can hold and deliver icariin efficiently, regardless of its incorporation mode, either as loaded into the MSNs or freely distributed within the hydrogel. Biocompatibility tests showed that the hydrogel nanocomposites assure enhanced osteoblast proliferation, adhesion, and differentiation. Such optimum biological properties stem from the superior biocompatibility of ADA-GEL, the bioactivity of the MSNs, and the supportive effect of icariin in relation to cell Proliferation and differentiation. Taken together, given the achieved structural and biological properties and effective drug delivery capability, the hydrogel nanocomposites show promising potential for bone tissue engineering.
KW - 3D printed hydrogel
KW - ADA-GEL
KW - Drug delivery
KW - Mesoporous SiO2-CaO nanoparticles
KW - Bone tissue engineering
PY - 2021
DO - https://doi.org/10.1016/j.msec.2021.112470
VL - 131
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-53848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
ED - Brockmann, S.
ED - Krupp, U.
T1 - Untersuchungsmethoden beim Fräsen additiv gefertigter schwer spanbarer Kobalt-Chrom-Legierungen
N2 - Für den Anlagenbau werden hochbelastete Komponenten aus Co-Cr-Legierungen hergestellt. Dabei ist die Zerspanung so herausfordernd, dass additive Fertigungsschritte oft wirtschaftlicher sind. Diese bedingen aber vorwiegende heterogene, anisotrope Gefüge und Eigenschaften und bei nachfolgender Fräsbearbeitung unstetige Zerspankräfte und instabile Spanvorgänge. Hierbei können hybride Zerspanprozesse helfen, hohe Belastungen für Werkzeug und Werkstückoberfläche zu minimieren. Diesbezügliche Charakterisierungen erfordern speziell adaptierte Zerspanungsanalysen.
Anhand eines Anwendungsbeispiels, bei dem eine Modifikation der Ausgangslegierung mit 1 % Hf erfolgte, wird die Wechselwirkung zwischen Gefügemorphologie und Fräsprozess dargestellt, der konventionelle mit einem hybriden ultraschallunterstützten Fräsprozess verglichen und die Charakterisierung des Werkzeugverschleißes anhand zweier verschiedener Fräser betrachtet. Analysen auftretender Prozesskräfte mittels Piezo-Mehrkomponenten-Dynamometer, der Werkzeugoszillation mittels Laser-Vibrometer und zusätzliche In-situ-Temperaturmessungen der Werkzeugschneiden mittels Highspeed-Pyrometer bilden den Kern der neuen Zerspanungsprüftechnik.
Die vorgestellten Untersuchungsmethoden bilden die Vorgänge bei der Zerspanung additiv gefertigter Werkstoffe detailliert und reproduzierbar ab. Sowohl Legierungsmodifikation als auch hybride Prozessbedingungen lassen gezielte Einflüsse zur deutlichen Verbesserung der Zerspanungssituation zu.
T2 - Tagung Werkstoffprüfung 2021
CY - Online meeting
DA - 02.12.2021
KW - Ultraschallunterstütztes Fräsen
KW - Legierungsmodifikation
KW - Additive Fertigung
KW - Plasma-Pulver-Auftragschweißen
KW - Werkzeugverschleiß
PY - 2021
SN - 978-3-941269-98-9
SP - 93
EP - 98
PB - Stahlinstitut VDEh
CY - Düsseldorf
AN - OPUS4-54921
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
T1 - Innovative Multielement-Legierungen: Aktuelle Ergebnisse zur Schweißbarkeit und Anwendungseigenschaften
N2 - Multielement-Legierungen (MPEA – multiple pricipal element alloys) stellen eine neue Klasse von Werkstoffen dar, die aus mindestens drei äquiatomaren Legierungselementen mit jeweils einem Gehalt von 5–35 Atom-% bestehen. Somit unterscheidet sich das Legierungskonzept fundamental von konventionellen bspw. Stahl- oder Al-basierten Legierungen. In jüngster Zeit lag der Schwerpunkt auf dem Legierungs-Design der MPEA und der Überprüfung bzw. Erreichung der gewünschten Eigenschaften bzw. -kombinationen. Hierzu werden die egierungselemente gezielt ausgewählt und die Mikrostrukturen ein- und zum Teil auch mehrphasig eingestellt. Ziel sind hochinnovative MPEA mit angepassten Eigenschaften für die industrielle Anwendung. Dabei sollen insbesondere die bei konventionellen Legierungen wesentlichen Zielkonflikte, wie bspw. der Trade-off zwischen Festigkeit und Duktilität, überwunden werden. Darüber hinaus sind mechanische Eigenschaften bei sehr hohen sowie kryogenen Temperaturen bei gleichzeitig höchster Korrosionsbeständigkeit von hohem Interesse. Die Herstellung von Bauteilen erfordert dazu werkstoff- und beanspruchungsgerechte Füge- bzw. Schweißverfahren. Der Schweißeignung von MPEA wurde bis Ende 2021 nur äußert wenig Aufmerksamkeit zuteil. Die Auswirkungen durch Schweißprozesse auf die Metallurgie und die gewünschten Eigenschaften sind bisher kaum bekannt und limitieren die potenzielle Anwendbarkeit als Funktions- oder Konstruktionswerkstoffe.
In einem interdisziplinären BAM-Forschungsprojekt werden aktuell grundlegende Untersuchungen zur Schweißverarbeitung und resultierender Mikrostruktur-Anwendungseigenschafts-Beziehung verschiedener MPEA durchgeführt. Insbesondere Wärmeeinflusszone und Schweißgut sind geprägt durch eine Mikrostruktur, die aus Ungleichgewichtszuständen resultiert. Im Falle von MPEA wurde dies bisher nicht systematisch untersucht. Dazu erfolgte im Rahmen des Projektes eine umfassende Literaturauswertung zum Schweißen von MPEA und Zusammenfassung in einer umfassenden, systematischen Datenbasis. Aus diesem Grund sollen in der vorliegenden Studie die bisher bedeutsamsten Erkenntnisse zur Schweißbarkeit von MPEA systematisch nach MPEA-Typ und Schweißverfahren geordnet und mit eigenen aktuellen Forschungsergebnissen verglichen werden. Durch WIG- und Rührreibschweißversuche an den MPEA-Systemen CoCrNiFeMn bzw. CoCrNi konnten im Projektverlauf bereits wesentliche Fragestellungen beantwortet werden. Dazu zählen Auftreten bzw. Verhinderung intermetallischer Phasen/Seigerungen oder deren Auswirkung auf die Eigenschaften der Schweißverbindung (bspw. Festigkeit oder Korrosionsbeständigkeit).
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - High Entropy Alloy
KW - Schweißen
KW - Multielementlegierungen
PY - 2022
SP - 62
EP - 67
AN - OPUS4-56706
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
T1 - Friction stir welding of a CoCrFeMnNi high entropy alloy compared to AISI 304 austenitic stainless steel: evolution of microstructure and mechanical properties
N2 - High entropy alloys (HEA) are a new class of materials. In contrast to conventional alloys, HEA are single-phase alloys with at least five alloying elements. HEAs have enormous application potential due to (postulated) excellent structural property combinations from low to high temperatures. For HEA-application as structural materials in real components, a key issue is the suitability for joining processing. Requirements for the reliable and safe joining of these materials are crucial regarding economical component manufacture for future applications. In this context, friction stir welding (FSW) is a promising joining process due to the welding process temperature below the material melting point avoiding major issues, e. g. formation of (hard and brittle) intermetallic phases, which may have detrimental influences on the weld joint properties.
This study presents elementary research about the FSW process influences on a CoCrFeMnNi-HEA with focus on the microstructure and mechanical properties. For that purpose, the FSW joint of the HEA is compared to that of an austenitic stainless steel AISI 304. The microstructures of the welds were investigated and characterized by means of light microscopy, SEM, EBSD and XRD. Hardness and tensile testing were applied to determine influences on the mechanical properties. Generally, a comparable weldability of HEA and AISI 304 in terms of metallurgical characteristics and resulting mechanical properties exhibited. For the weld joints of both materials typical characteristics regarding FSW were observed within the weld metal and thermo-mechanically influenced zone: fine-grained stirred zone with increased hardness and reduced fracture elongation compared with the respective base material.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Magdeburg, Germany
DA - 20.10.2021
KW - High Entropy Alloy
KW - Friction stir welding
KW - Austenitic stainless steel
PY - 2021
AN - OPUS4-53608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sankaran, Shivasarathy
A1 - Ebell, Gino
T1 - Analyzing the performance of discrete galvanic anode systems using electrochemical investigations
N2 - Corrosion of reinforcement is one of the major reasons in questioning the service life of building structures. The application of cathodic protection techniques plays a big role in controlling the corrosion process to ensure a longer service life of building structures. This systematic study compares the efficiency and durability of various discrete galvanic zinc anode systems available in the current market using different criteria for measuring efficiency such as potential measurements, electrolyte resistance measurements and several polarization methods to determine the polarizability of the anodes. The results to validate the performance of long-time exposure of discrete zinc anodes in concrete medium are discussed.
T2 - EUROCORR 2021
CY - Online meeting
DA - 20.09.2021
KW - Corrosion
KW - Cathodic Protection
KW - Zinc anodes
KW - Electrochemical
PY - 2021
AN - OPUS4-53507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - The European Metrology Network (EMN) for Advanced Manufacturing
N2 - Advanced Manufacturing and Advanced Materials have been identified by the European Commission as one of six Key Enabling Technologies (KETs), the full exploitation of which will create advanced and sustainable economies. Metrology is a key enabler for progress of these KETs. EURAMET, which is the association of metrology institutes in Europe, has addressed the vital importance of Metrology for these KETs through the support for the creation of a European Metrology Network for Advanced Manufacturing. The EMN for Advanced Manufacturing (AdvanceManu) was approved in June 2021 and held the formal kick-of meeting in October 2022. The EMN comprises both National Metrology Institutes (NMIs) from across Europe and other designated Institutes (Dis). The EMN is organized in three sections; Advanced Materials, Smart Manufacturing Systems and Manufactured components and products. The aim of the EMN is to engage with stakeholders in the field of Advanced Manufacturing and Advanced Materials (Large & SMEs, industry organisations, existing networks and academia) with the aim to prepare a Strategic Research Agenda (SRA) for Metrology for Advanced Manufacturing. In the shorter term, an orientation paper is aimed to be produce to in the context of the European Partnership for Metrology. In addition to the SRA, the EMN will establish knowledge and technology transfer and promotion plan. This includes leveraging the existing research results from the completed and running EMPIR JRP projects funded through EURAMET.
This presentation will outline the EMN for Advanced Manufacturing, describing the structures and goals, the route to the production of the SRA and the progress made to date identifying the key metrology challenges across the related Key Industrial Sectors (KICs). In particular, the presentation aims to inform the community on how to be involved in the shaping of the strategic research agenda for the future of Metrology for Advanced Manufacturing and Advanced Materials.
T2 - 3D Metrology Conference (3DMC)
CY - Online meeting
DA - 08.11.2021
KW - Advanced manufacturing
KW - Metrology
KW - European Metrology Network (EMN)
KW - Strategic Research Agenda (SRA)
KW - JNP
PY - 2021
AN - OPUS4-54099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernádez-Canteli, A.
A1 - Castillo, E.
A1 - Blasón Gonzalez, Sergio
A1 - Correia, J. A. F. O.
A1 - de Jesus, A. M. P.
T1 - Generalization of the Weibull probabilistic compatible model to assess fatigue data into three domains: LCF, HCF and VHCF
N2 - n this work, three classes of fatigue models are reviewed according to the fatigue regimes commonly considered in the current components design. Particular attention is devoted to the so-called Class III fatigue models, covering the three fatigue regimes, namely, LCF, HCF and VHCF. The applicability and limitations of the pro-posed analytical sigmoidal solutions are discussed from the viewpoint of practical design. The compatible Weibull S-N model by Castillo and Canteli is revisited and improved by considering a new reference parameter GP = E⋅σM ⋅(dε/dσ)|M as the driving force alternative to the conventional stress range. In this way, the requirement, σM ≤ σu, according to the real experimental conditions, is fulfilled and the parametric limit number of cycles, N0, recovers its meaning. The probabilistic definition of the model on the HCF and VHCF regimes is maintained and extended to the LCF regime. The strain gradients may be calculated from the monotonic or cyclic stress–strain curve of the material although a direct derivation from the hysteresis loop is recommended. Some Class III fatigue models from the literature and another one improved by the authors are applied to the assessment of one experimental campaign under different stress ratios conditions and the results compared accordingly. Finally, the new probabilistic GP-N field is evaluated. The results confirm the practical confluence of the stress- and the strain-based approaches into a single and advantageous unified methodology.
KW - LCF region
KW - S-N probabilistic field
KW - Energetic reference parameter
PY - 2022
DO - https://doi.org/10.1016/j.ijfatigue.2022.106771
SN - 0142-1123
VL - 159
SP - 1
EP - 18
PB - Elsevier Ltd.
AN - OPUS4-55235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Przyklenk, A.
T1 - Progress of the European Metrology Network for Advanced Manufacturing
N2 - The European Metrology Network (EMN) for Advanced Manufacturing has been established in June 2021. Currently nine EMNs focussing on different important topics of strategic importance for Europe exist and form an integral part of EURAMET, the European Association of National Metrology Institutes (NMI). EMNs are tasked to ▪ develop a high-level coordination of the metrology community in Europe in a close dialogue with the respective stakeholders (SH)
▪ develop a strategic research agenda (SRA) within their thematic areas
▪ provide contributions to the European Partnership on Metrology research programme Based on the analysis of existing metrology infrastructures and capabilities of NMIs, the metrology research needs for advanced manufacturing are identified in close cooperation with academic, governmental and industrial stakeholders.
Here, we report on the progress of the EMN for Advanced Manufacturing.
T2 - Euspen 22nd International Conference & Exhibition (Euspen 2022)
CY - Genf, Switzerland
DA - 30.05.2022
KW - JNP AdvManuNet
KW - Metrology
KW - Advanced manufacturing
KW - European Metrology Network
KW - EMN
PY - 2022
AN - OPUS4-55805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
T1 - Concepts for bridging voids in metal additive manufacturing for repair of gas turbine blades using laser powder bed fusion
N2 - One of the main advantages of additive manufacturing (AM) processes such as laser powder bed fusion (PBF-LB/M) is the possibility to manufacture complex near-net-shape components. Therefore, the PBF-LB/M process is becoming increasingly important for the manufacturing and repair of gas turbine blades. Despite the great freedom in design, there are also limitations to the process. Manufacturing overhangs or bridging voids are some of the main challenges. In the conventional PBF-LB/M process, overhangs with angles up to 45° can be manufactured. However, gas turbine blades feature voids for cooling, which have to be bridged when using PBF-LB/M. In this work, different concepts for bridging voids are developed for future application in gas turbine blade repair. For this purpose, a test geometry is derived from the tip area of a gas turbine blade as a reference. By changing the initial geometry of the reference body, different designs for bridging voids are developed based on the PBF-LB/M requirements. Subsequently, these distinct designs are manufactured by PBF-LB/M. The different approaches are compared with respect to their volume increase. In addition, the specimens are visually inspected for warpage, shrinkage and imperfections by overheating. Out of the seven concepts developed, three concepts can be recommended for gas turbine blade repair based on low volume increase, distortion and shrinkage.
T2 - Metal Additive Manufacturing Conference - MAMC 2022
CY - Graz, Austria
DA - 26.09.2022
KW - Laser Powder Bed Fusion (PBF-LB/M)
KW - Selective Laser Melting (SLM)
KW - Design for Additive Manufacturing (DfAM)
KW - Repair of gas turbine blades
KW - Bridging voids
KW - Supportless
PY - 2022
AN - OPUS4-55869
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
T1 - Position Detection for Hybrid Repair of gas turbine blades using PBF-LB/M
N2 - This poster presents a workflow for camera-based position detection of components within PBF-LB/M machines. This enables a hybrid repair process of highly stressed components such as gas turbine blades using PBF-LB/M.
T2 - Kuratoriumsführung
CY - Berlin, Germany
DA - 21.06.2022
KW - Additive Manufacturing
KW - PBF-LB/M
KW - Position detection
KW - Camera
KW - Image processing
PY - 2022
AN - OPUS4-56587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Modifikation von CoCr Legierungen für die additive lichtbogenbasierte Fertigung
N2 - Für Komponenten im Turbinen- oder Anlagenbau werden aufgrund ihrer Eigenschaften häufig Kobalt-Chrom-Legierungen verwendet. Diese weisen eine hohe Korrosionsbeständigkeit und hohen Verschleißwiederstand auf. Aufgrund der komplexen Strukturen und dem Bestreben nach Ressourceneffizienz wird zur Herstellung der Komponenten die additive Fertigung verwendet. Hierbei sind hinsichtlich der Inhomogenität und Anisotropie der Gefüge und deren Eigenschaften weitere Kenntnisse notwendig. Bei den vorliegenden Belastungen liegt ein erhöhter Anspruch an die Oberflächenintegrität vor, welcher durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten sichergestellt wird. Dabei sind gerade Co-Cr-Legierungen wegen der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ausgehend von dieser Problemstellung erfolgt im Zuge eines Gemeinschaftsvorhabens des ISAF in Kooperation mit der BAM eine gezielte Beeinflussung des Gefüges. Ziel des Projektes ist die Zusammenhänge zwischen verschiedenen Legierungsmodifikationen, der entstehenden Gefügemorphologie und den Zerspanungseigenschaften von Co- Cr-Legierungen für die additive Fertigung mittels PTA darzustellen. Der Fokus liegt auf dem Beheben der bestehenden Nachteile bei gleichzeitigem Aufrechthalten der besonderen Eigenschaften der Legierung. Durch das Hinzulegieren von variierenden Gehalten von Zirkonium und Hafnium wird die Gefügeveränderung eingestellt. Es hat sich gezeigt, dass Hafnium als zusätzliches Legierungselement einen deutlichen Einfluss auf die Gefügemorphologie hat. Darüber hinaus wird die Auswirkung der Legierungsmodifikation auf die Härte und die Zerspanbarkeit dargestellt.
T2 - 42. Assistentenseminar der Wissenschaftlichen Gesellschaft Fügetechnik e.V.
CY - Blankenau, Germany
DA - 06.10.2021
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2021
AN - OPUS4-56659
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilke, Olaf
A1 - Horn, Wolfgang
A1 - Richter, Matthias
A1 - Jann, Oliver
T1 - Volatile organic compounds from building products - Results from six round robin tests with emission test chambers conducted between 2008 and 2018
N2 - Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt für Materialforschung und -prüfung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m3. This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m3. In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28 % in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51 %.
KW - Construction product
KW - Emission test chamber
KW - Interlaboratory comparison
KW - Proficiency testing
KW - Rround robin test
KW - VOC emission
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526139
DO - https://doi.org/10.1111/ina.12848
VL - 31
IS - 6
SP - 2049
EP - 2057
PB - Wiley
AN - OPUS4-52613
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique Authenticator for additively manufactured parts
N2 - Components produced using additive manufacturing can be marked for unique identification and secure authentication [1,2]. Serial numbers and machine-readable codes can be used to identify the component, and link digital product-related data (i.e., a digital product passport) to the actual components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface of the internal cavity of hollow components. However, local manipulation of components may alter the properties, and external tagging features can be altered or even removed by post-processing treatments. This work therefore aims to provide a new methodology for identification, authentication, and traceability of additively manufactured (AM) components using microstructural features that are unique to each part. X-ray computed tomography (XCT) was employed to image the microstructural features of AlSi10Mg parts. Based on size and geometry, the most prominent features were selected to create a unique digital authenticator. We implemented a framework in Python using open-access modules that can successfully create a digital object authenticator using the segmented microstructure information from XCT. The authenticator is stored as a QR code, along with the 3D information of the selected features.
T2 - DGM Additive Berlin 2024
CY - Berlin, Germany
DA - 12.06.2024
KW - Additive Fertigung
KW - Authentifizierung
KW - Mikrostruktur
PY - 2024
AN - OPUS4-60957
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Preuß, Bianca
A1 - Lindner, Thomas
A1 - Hanisch, Niclas
A1 - Giese, Marcel
A1 - Schröpfer, Dirk
A1 - Richter, Tim
A1 - Rhode, Michael
A1 - Lampke, Thomas
T1 - Surface Functionalization of Novel Work‐Hardening Multi‐Principal‐Element Alloys by Ultrasonic Assisted Milling
N2 - The development of multi‐principal‐element alloys (MPEAs) with unique characteristics such as high work hardening capacity similar to well‐known alloy systems like Hadfield steel X120Mn12 (ASTM A128) is a promising approach. Hence, by exploiting the core effects of MPEAs, the application range of conventional alloy systems can be extended. In the present study, work‐hardening MPEAs based on the equimolar composition CoFeNi are developed. Mn and C are alloyed in the same ratio as for X120Mn12. The production route consists of cast manufacturing by an electric arc furnace and surface functionalization via mechanical finishing using ultrasonic‐assisted milling (USAM) to initiate work hardening. The microstructure evolution, the hardness as well as the resulting oscillating wear resistance are detected. A pronounced lattice strain and grain refinement due to the plastic deformation during the USAM is recorded for the MPEA CoFeNi‐Mn12C1.2. Consequently, hardness increases by ≈380 HV0.025 in combination with a higher oscillating wear resistance compared to the X120Mn12. This shows the promising approach for developing work‐hardening alloys based on novel alloy concepts such as MPEAs.
KW - Electric arc furnace
KW - Finish milling
KW - High manganese steels
KW - Multi-principal element alloy
KW - Ultrasonic-assisted milling
KW - Work hardening
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608008
DO - https://doi.org/10.1002/adem.202400339
SN - 1438-1656
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-60800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heyn, A.
A1 - Meist, M.
A1 - Michael, O.
A1 - Babutzka, M.
A1 - Valet, Svenja
A1 - Ebell, Gino
T1 - Electrochemical characterization of surfaces of galvanized steels under different exposure conditions using gel electrolytes
N2 - The corrosion behavior of galvanized steels and zinc components under atmospheric exposure depends mostly on the corrosion product‐based cover layer formation under the prevailing conditions. The use of agar‐based gel electrolytes makes it possible to use electrochemical methods to obtain a characteristic value from these cover layers that describe their current and future protective capacity. It is shown here that different states of galvanized steel can be distinguished very well under laboratory conditions and that this method is also suitable for use under practical conditions. Based on the characteristic values and assuming future time of wetness, it is very easy to draw up a forecast for the future corrosion rate, which provides plausible values.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - Environmental Chemistry
KW - Corrosion
KW - Znc
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599234
DO - https://doi.org/10.1002/maco.202414389
SP - 1
EP - 16
PB - Wiley VHC-Verlag
AN - OPUS4-59923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Mente, Tobias
T1 - Trapping and diffusion in high-pressure hydrogen charged CoCrFeMnNi high entropy alloy compared to austenitic steel 316L
N2 - High entropy alloys (HEAs) have attracted considerable research attention as potential substitute materials for austenitic steels in high-pressure hydrogen environments. The corresponding hydrogen absorption, diffusion and trapping has received less scientific attention. Therefore, the CoCrFeMnNi-HEA was investigated and compared to an austenitic steel AISI 316L. Both were subjected to high-pressure hydrogen charging at 200 bar and 1000 bar. Thermal Desorption Analysis (TDA) was used to clarify the specific desorption behavior and hydrogen trapping. For this purpose, the underlying TDA spectra were analyzed in terms of a reasonable peak deconvolution into a defined number of peaks and the activation energies for the respective and predominant hydrogen trapping sites were then calculated. Both materials show comparable hydrogen diffusivity. However, there were significant differences in the absorbed hydrogen concentrations at both charging pressures. The calculated activation energies suggest strong hydrogen trapping in the CoCrFeMnNi-HEA.
KW - High-entropy alloy
KW - Hydrogen diffusion
KW - Trapping
KW - High-pressure charging
KW - Thermal desorption analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611901
DO - https://doi.org/10.1016/j.ijhydene.2024.09.393
SN - 0360-3199
VL - 89
IS - 89
SP - 772
EP - 782
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-61190
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Rhode, Michael
T1 - Normungsroadmap Wasserstofftechnologien 2024
N2 - Im Auftrag des Bundesministeriums für Wirtschaft und Klimaschutz (BMWK) wurden Anfang 2023 unter Leitung der Projektpartner DIN, DKE, DVGW, NWB, VDA, VDI und VDMA die Arbeiten an der Normungsroadmap Wasserstofftechnologien (NRM H2) begonnen. Ziel des Verbundprojekts war es, einen strategischen Fahrplan für eine schnelle und gezielte Erweiterung und Anpassung des technischen Regelwerks im Bereich der Wasserstofftechnologien auszuarbeiten und die aufgezeigten Lücken effizient zu schließen. Die Erarbeitung erfolgte in 39 Arbeitsgruppen mit einer Beteiligung von mehr als 600 Expertinnen und Experten. Die Clusterung erfolgte auf Basis von fünf großen Themenfeldern, die die gesamte Wertschöpfungskette abdecken: - Erzeugung - Infrastruktur - Anwendung - Qualitätsinfrastruktur - Weiterbildung, Zertifizierung und Sicherheit. Im Rahmen der des AK Infrastruktur erfolgte die Mitarbeit in der Arbeitsgruppe „Rohrleitungen“ (AG 2.1.1). Die AG war zuständig für die Ermittlung der Normungsbedarfe auf dem Gebiet der industriellen Rohrleitungen zur Werksversorgung sowie dem Gebiet der Flansche und ihren Verbindungen wie auch Prozessleitungen. Dies umfasst unter anderem Anforderungen für oberirdische oder in Kanälen verlegte oder erdgedeckte Rohrleitungen aus metallischen und nichtmetallischen Werkstoffen für Wasserstoff und -gemische. Mit dem Ziel, sicherer Betriebsbedingungen, waren hierbei insbesondere Anforderungen für industrielle Rohrleitungssysteme von Bedeutung (z. B. Normenreihe DIN EN 13480). Dabei unterscheiden sich die industriellen Rohrleitungssysteme von Fern- bzw. Transportleitungen, außerhalb der industriellen Werke, bspw. Raffinerien. Diese waren Bestandteil der AG 2.1.2 „Transportleitungen“.
KW - Normung
KW - Wasserstoff
KW - Rohrleitungen
KW - Metallische Werkstoffe
KW - Regelwerke
PY - 2024
SP - 49
EP - 54
AN - OPUS4-62442
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Diffusion in high-pressure hydrogen charged multi-principal element alloys CoCrFeMnNi and CoCrNi vs. AISI 316L
N2 - Multi-principal element alloys (MPEAs) are innovative materials that have attracted extensive research attention within the last decade. MPEAs are characterized by a solid solution of equiatomic metallic elements. Depending on the number of elements, they are also referred as high entropy alloys (HEAs with n ≥ 4 elements like CoCrFeMnNi) and medium-entropy alloys (MEA with n = 3 elements CoCrNi). Depending on the alloy concept, MPEAs show exceptional properties in terms of mechanical performance or corrosion resistance at extreme environments. In that connection, hydrogen and its challenges for the most metallic materials gets more and more important. MPEAs are candidate materials for the substitution of conventional materials like austenitic stainless steels e.g., at very high-pressure up to 1000 bar. Those pressures are typically reached in valves or compressors for refueling of tanks with operational pressure of 700 bar. So far, the susceptibility of HEA/MEAs to hydrogen assisted cracking (if any) and the especially the underlying hydrogen uptake and diffusion was not within the scientific scope and not investigated in detail yet. For that reason, we focused on the hydrogen absorption the characterization of the hydrogen diffusion and trapping at elevated temperatures in a CoCrFeMnNi-HEA (each element with 20 at.-%) and CoCrNi-MEA, each element with 33.3 at.-%). As reference grade, the commercially available austenitic stainless steel AISI 316L was investigated. High-pressure hydrogen charging was conducted at different pressures in autoclave environment with maximum value of 1,000 bar. Thermal desorption analysis (TDA) via carrier gas hot extraction with coupled mass spectrometry was used with a max. heating rate of 0.5 K/s up to 650 °C. The measured desorption spectra of the different samples were deconvoluted into a defined number of individual peaks. The individually calculated peak temperatures allowed the definition of activation energies for predominant trap sites in the respective materials as well as the percentage share of the totally absorbed hydrogen concentration. The results present for the first time the complex interaction of both MPEAs and high-pressure hydrogen charging. A deconvolution of four peaks was selected and a main desorption peak was identified the dominant hydrogen trap containing the biggest share of the absorbed hydrogen concentration. The chemical composition an austenitic phase of both MPEAs is responsible for delayed hydrogen diffusion and strong, but mostly reversible, trapping. The comparison with the 316L samples showed significantly higher activation energies in the MPEAs, whereas hydrogen was also trapped at very high extraction temperatures. The absorbed maximum hydrogen concentration at 1,000 bar was 130 ppm for the CoCrFeMnNi-HEA, 50 ppm for the CoCrNi-MEA and 80 ppm for the 316L. It is interesting that the CoCrFeMnNi-HEA has obviously a way higher trapping capability compared to the conventional austenitic 316L, which could be a major advantage in terms of resistance to hydrogen assisted cracking.
T2 - 47th MPA-Seminar
CY - Stuttgart, Germany
DA - 10.10.2023
KW - High-entropy alloy
KW - Hydrogen
KW - Diffusion
KW - Thermal desorption analysis
KW - Multiple-principal element alloy
PY - 2023
AN - OPUS4-58675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Residual stresses in near-component specimens of a high and a medium entropy alloy due to tig and friction stir welding
N2 - The new alloying concept of multi-element systems with defined entropy (HEA - High Entropy Alloy or MEA - Medium Entropy Alloy) is gaining increasing importance in materials research. Significantly improved properties or combinations of properties are shown by some HEA/MEA-systems. Thus, primarily the production and resulting microstructures of HEA as well as properties have been investigated so far. Furthermore, processing is a main issue to transfer HEA systems from the laboratory to real components. Since welding is the most important joining process for metals, it is crucial to investigate the influence of welding to guarantee component integrity. Welding leads to residual stresses, which significantly affect the component integrity. Hence, the focus of this study is the residual stress formation and distribution in a CoCrFeMnNi HEA and ternary CoCrNi MEA using two different welding processes: Tungsten Inert Gas (TIG) welding and soldi-state Friction Stir Welding (FSW). As a pathway for application of HEA in this investigation for the first-time residual stress analyses in realistic near-component specimens were performed. The residual stresses were determined by X-ray diffraction (XRD) on the surfaces of top and root weld side. The results were correlated with the local welding microstructures. The results show that both FSW and TIG generate significant tensile residual stresses on the weld surfaces in and transverse to the welding direction. In the case of FSW of the CoCrFeMnNi HEA, the longitudinal residual stresses are in the range of the yield strength of approx. 300 MPa in the weld zone.
T2 - ICRS11 – 11th International Conference on Residual Stresses
CY - Nancy, France
DA - 27.03.2022
KW - High Entropy Alloy
KW - Medium Entropy Alloys
KW - Welding microstructure
KW - Residual stresses
PY - 2022
AN - OPUS4-55444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
T1 - Local mechanical properties of TIG dissimilar metal welded CoCrFeMnNi high-entropy alloy to austenitic steel AISI 304
N2 - Multiple principal element alloys (MPEA) encompass the well-known high entropy alloys (HEAs). MPEA/HEA represent a new class of materials consisting of at least three alloying elements, each containing 5 to 35 at.-%. This alloying concept thus differs fundamentally from conventional materials such as steel or nickel alloys. For this purpose, the alloying elements are specifically selected, and the microstructures are adjusted in a single-phase and, in some cases, multi-phase manner. In particular, conflicting goals, such as the trade-off between strength and ductility in conventional steels, are overcome. In the last 20 years, however, the focus has been on material synthesis. With the increase in available material quantities, the focus is now on pro-cessing issues such as joining and welding processes. The weldability of MPEA has received very little atten-tion so far. Experience with dissimilar metal welds (DMWs) is completely lacking but is essential for the appli-cation of these materials in combination with conventional materials. The present study presents, comprehen-sive experimental results on the weldability of MPEA-DMWs. For that purpose, a Co20Cr20Fe20Mn20Ni20 HEA in cold-rolled and heat-treated condition was joined by means of tungsten inert gas welding (TIG) with the austenitic Cr-Ni steel AISI 304. The DMWs resulted in interesting mechanical properties. They were obtained by instrumented tensile tests as well as the local deformation in the weld area by using digital image correlation (DIC) technique. A significant softening in the heat-affected zone (HAZ) of the MPEAs as well as a slightly reduced tensile strength with a significant decrease of the elongation at fracture were found. The experiments provided proof in principle of the weldability of the MPEAs for DMWs with conventional materials that ensure a corresponding capability for mechanical loading. This allows further considerations on the application of these innovative materials.
T2 - IIW Annual Assembly, Meeting of Commission C-II
CY - Singapore
DA - 18.07.2023
KW - High-entropy alloy
KW - Welding
KW - Microstructure
KW - Mechanical properties
KW - Dissimilar metal weld
PY - 2023
AN - OPUS4-57978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Richter, Tim
A1 - Mente, Tobias
A1 - Mayr, P.
A1 - Nitsche, A.
T1 - Thickness and microstructure effect on hydrogen diffusion in creep‑resistant 9% Cr P92 steel and P91 weld metal
N2 - Martensitic 9% Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. Limited data on room temperature diffusion coefficients reported in literature vary widely by several orders of magnitude (mostly attributed to variation in microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. From the results obtained, diffusion coefficients were calculated using to different methods, time-lag, and inflection point. Results show that, despite microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients.
KW - Creep-resistant steel
KW - Diffusion
KW - Hydrogen assisted cracking
KW - Welding
KW - Electrochemical permeation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540645
DO - https://doi.org/10.1007/s40194-021-01218-9
SN - 0043-2288
SP - 1
EP - 16
PB - Springer Nature Switzerland AG
AN - OPUS4-54064
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Experimentelle Charakterisierung der WIG-Schweißeignung einer Hoch- und Mittelentropie-Legierung
N2 - Hoch- und Mittelentropie-Legierungen (engl. High/Medium Entropy Alloys–HEA/MEA) sind relativ neue Werkstoffklassen. Im Gegensatz zu herkömmlichen Legierungen bestehen HEA aus fünf bzw. MEA aus drei oder vier Legierungselementen im äquiatomaren Gleichgewicht. Um diese als reale Bauteile in die Anwendung zu überführen, muss die Verarbeitbarkeit ausführlich erforscht werden. In dieser Präsentation werden dafür erste Ergebnisse der schweißtechnischen Verarbeitung mittels WIG-Schweißen dargestellt. Dazu wurden zunächst die Schweißparameter mit einer Referenzlegierung (Ni-Basislegierung: 2.4858) bestimmt und auf eine CoCrFeMnNi-HEA sowie eine CoCrNi-MEA übertragen.
T2 - OVGU-Kolloquium
CY - Online meeting
DA - 23.06.2021
KW - Hochentropielegierung
KW - Mediumentropielegierung
KW - WIG-Schweißen
PY - 2021
AN - OPUS4-56621
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sprachmann, J.
A1 - Grabicki, N.
A1 - Möckel, Anna
A1 - Maltitz, J.
A1 - del Refugio Monroy Gómez, J.
A1 - Smales, Glen Jacob
A1 - Dumele, O.
T1 - Substituted Benzophenone Imines for COF Synthesis via Formal Transimination
N2 - Covalent organic frameworks (COFs) are a prominent class of organic materials constructed from versatile building blocks via reversible reactions. The quality of imine-linked COFs can be improved by using amine monomers protected with benzophenone forming benzophenone imines. Here, we present a study on substituted benzophenones in COF synthesis via formal transimination. 12 para-substituted N-aryl benzophenone imines, with a range of electron-rich to electron-poor substituents, were prepared and their hydrolysis kinetics were studied spectroscopically. All substituted benzophenone imines can be employed in COF synthesis and lead to COFs with high crystallinity and high porosity. The substituents act innocent to COF formation as the substituted benzophenones are cleaved off. Imines can be tailored to their synthetic demands and utilized in COF formation. This concept can make access to previously unattainable, synthetically complex COF monomers feasible.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - General Chemistry
KW - Ceramics and Composites
KW - Electronic, Optical and Magnetic Materials
KW - Catalysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586449
DO - https://doi.org/10.1039/D3CC03735E
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dal Molin, E. S.
A1 - Henning, L. M.
A1 - Müller, J. T.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Bekheet, M. F.
A1 - Gurlo, A.
A1 - Simon, U.
T1 - Robocasting of ordered mesoporous silica‐based monoliths: Rheological, textural, and mechanical characterization
N2 - Hierarchically porous, high‐surface‐area silica materials are excellent candidates for multiple applications like catalysis and environmental remediation. Shaping these materials with additive manufacturing (AM) techniques, like robocasting, could enable their use with the benefit of on‐demand, customized shaping and maximizing performance. Herein, ordered mesoporous silica COK‐12 slurries were robocasted into monoliths, containing different ratios of uncalcined COK‐12 and sodium bentonite (0–25 wt.%). The rheology of the mixed slurries is characterized by lower flow indexes (0.69 vs. 0.32) and higher yield stresses (96 vs. 259 Pa) compared to pure COK‐12 ones. Monoliths were printed in woodpile structures and calcined at 600°C. Micro‐CT measurements showed a linear shrinkage of 25% after calcination. Mechanical characterization showed increased uniaxial strength (0.20 ± 0.07 to 1.0 ± 0.3 MPa) with increasing binder/solids ratio from 13 to 25%. The amorphous, mesoporous structure of COK‐12 was retained. The structures exhibited open porosities of 52 ± 4% and showed higher specific mesopore volumes, and increased average mesopore size (6 vs. 8 nm) compared to COK‐12. Small‐angle x‐ray scattering analysis revealed an increased lattice parameter (10.3 vs. 11.0 nm) and reduced wall thickness (3.1 nm vs. 4.1 nm) of the COK‐12 in the monoliths. These properties indicate suitability for their application as porous supports and adsorbents.
KW - Industrial and Manufacturing Engineering
KW - Additive manufacturing
KW - OMS
KW - Porous materials
KW - Robocasting
KW - X-ray scattering
KW - MOUSE
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582503
DO - https://doi.org/10.1002/nano.202300109
VL - 4
IS - 11-12
SP - 615
EP - 631
PB - Wiley-VCH GmbH
AN - OPUS4-58250
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Foroutan, Farzad
A1 - Abrahams, Isaac
A1 - Smales, Glen Jacob
A1 - Kanwal, Nasima
A1 - di Pasquale, Roberto
A1 - Knowles, Jonathan C.
A1 - Smith, Andrew J.
A1 - Carta, Daniela
T1 - A sol-gel templating route for the synthesis of hierarchical porous calcium phosphate glasses containing zinc
N2 - Hierarchical porous phosphate-based glasses (PPG) have great potential in biomedicine. Micropores (pore size <2 nm) increase the surface area, mesopores (pore size 2–50 nm) facilitate the absorption and diffusion of therapeutic ions and molecules making them ideal controlled delivery systems, while macropores (pore size >50 nm) facilitate the movement and diffusion of cells and fluids. In addition, the bioresorbability of PPG allows for their complete solubility in body fluid, alongside simultaneous formation of new tissue. Making PPG via the traditional melt-quenching (MQ) synthesis method used for phosphate-based glasses (PG), is not straightforward. Hence, we present here a route for preparing such glasses using a combination of sol-gel (SG) and templating methods. Hierarchical PPG in the P₂O₅–CaO–Na₂O system with the addition of 1, 3 and 5 mol % of Zn²⁺ were prepared with pore dimensions ranging from the micro-to the macro scales using Pluronic 123 (P123) as a surfactant. The presence of micropores (0.30–0.46 nm), mesopores (1.75–9.35 nm) and macropores (163–207 nm) was assessed via synchrotron-based Small-Angle X-ray Scattering (SAXS), with the presence of the latter two confirmed by Scanning Electron Microscopy (SEM). Structural characterisation performed using ³¹P solid state magic angle spinning nuclear magnetic resonance (MAS NMR) and Fourier Transform Infrared (FTIR) spectroscopies shows the presence of Q², Q¹ and Q⁰ phosphate species with a predominance of Q¹ species in all compositions. Dissolution studies in deionised (DI) water confirm that controlled release of phosphates, Ca²⁺, Na⁺ and Zn²⁺ is achieved over a period of 7 days. In particular, the release of Zn²⁺ is proportional to its loading, making its delivery particularly easy to control.
KW - Sol-gel
KW - Phosphate-based glasses
KW - Mesoporous materials
KW - Hierarchical porosity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613698
DO - https://doi.org/10.1016/j.ceramint.2024.07.180
SN - 0272-8842
VL - 50
IS - 20, Part A
SP - 38174
EP - 38182
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hayward, E. C.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Takeguchi, M.
A1 - Kulak, A.
A1 - Hunter, R. D.
A1 - Schnepp, Z.
T1 - The effect of catalyst precursors on the mechanism of iron-catalysed graphitization of cellulose
N2 - Iron-catalysed graphitization of biomass is a simple and sustainable route to carbons with high graphitic content. It uses abundant precursors and moderate processing temperatures and generates carbons with high porosity. Recently, it has been demonstrated that the choice of biomass precursor can have a significant impact on the textural and compositional properties of the resulting carbon. In this paper, we demonstrate that the choice of catalyst is also critical to the carbon structure. Aqueous iron(III) nitrate and iron(III) chloride convert cellulose to carbons with very different textural properties. This is due to the choice of iron catalyst changing the mechanism of cellulose decomposition and also the nature of the active graphitization catalyst.
KW - Catalyst
KW - Carbon materials
KW - Cellulose
KW - Small-angle scattering
KW - Green energy
KW - Graphitic carbon
KW - Green synthesis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614800
DO - https://doi.org/10.1039/D4SU00365A
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hallier, Dorothea C.
A1 - Smales, Glen Jacob
A1 - Seitz, H.
A1 - Hahn, Marc Benjamin
T1 - Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine
N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies.
KW - BioSAXS
KW - Bio-SAXS
KW - Cosolute
KW - Ectoine
KW - G5P
KW - GVP
KW - Radiation damage
KW - Radical Scavenger
KW - Single-stranded DNA-binding proteins
KW - X-ray scattering
KW - DNA
KW - ssDNA
KW - Protein
KW - SAXS
KW - Small-angle xray scattering
KW - McSAS3
KW - Dosimetry
KW - Microdosimetry
KW - Geant4
KW - Geant4-DNA
KW - Topas
KW - Topas-MC
KW - Monte-Carlo simulations
KW - Particle scattering simulations
KW - Topas-nBio
KW - OH Radical
KW - OH radical scavenger
KW - LEE
KW - Ionizing radiation damage
KW - Protein unfolding
KW - Ectoin
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568909
DO - https://doi.org/10.1039/d2cp05053f
SN - 1463-9076
SN - 1463-9084
VL - 25
IS - 7
SP - 5372
EP - 5382
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-56890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hallier, Dorothea C.
A1 - Smales, Glen Jacob
A1 - Seitz, H.
A1 - Hahn, Marc Benjamin
T1 - Inside back cover for the article "Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine"
N2 - Showcasing research from the Federal Institute for Material Research and Testing Berlin and Fraunhofer Institute for Celltherapy and Immunology Branch Bioanalytics and Bioprocesses Potsdam.
Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine.
We aimed to increase the possible undisturbed exposure time during bio-SAXS measurements of single-stranded DNA-binding proteins. Therefore small angle X-ray scattering was performed on Gene-V Protein (G5P/GVP), which is involved in DNA repair processes. To achieve this, irradiations were performed in presence and absence of the hydroxyl-radical scavenger and osmolyte Ectoine, which showed efficient radiation protection and prevented protein aggregation, thus allows for a non-disturbing way to improve structure-determination of biomolecules.
KW - Bio-SAXS
KW - BioSAXS
KW - Cosolute
KW - DNA
KW - Dosimetry
KW - Ectoin
KW - Ectoine
KW - G5P
KW - GVP
KW - Geant4
KW - Geant4-DNA
KW - Ionizing radiation damage
KW - LEE
KW - McSAS3
KW - Microdosimetry
KW - Monte-Carlo simulations
KW - OH Radical
KW - OH radical scavenger
KW - Protein
KW - Protein unfolding
KW - Radiation damage
KW - Radical Scavenger
KW - SAXS
KW - Single-stranded DNA-binding proteins
KW - Small-angle xray scattering
KW - Topas-MC
KW - Topas-nBio
KW - TopasMC
KW - X-ray scattering
KW - Particle scatterin simulations
KW - ssDNA
PY - 2023
DO - https://doi.org/10.1039/D3CP90056H
SN - 1463-9076
SN - 1463-9084
VL - 25
IS - 7
SP - 5889
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-57006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hunter, R. D.
A1 - Hayward, E. C.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Kulak, A.
A1 - Guan, S.
A1 - Schnepp, Z.
T1 - The effect of nitrogen on the synthesis of porous carbons by iron-catalyzed graphitization
N2 - This paper reports a systematic study into the effect of nitrogen on iron-catalyzed graphitization of biomass. Chitin, chitosan, N-acetylglucosamine, gelatin and glycine were selected to represent nitrogen-rich saccharides and amino-acid/polypeptide biomass precursors. The materials were pyrolyzed with an iron catalyst to produce carbons with a wide range of chemical and structural features such as mesoporosity and nitrogen-doping. Many authors have reported the synthesis of nitrogen-doped carbons by pyrolysis and these have diverse applications. However, this is the first systematic study of how nitrogen affects pyrolysis of biomass and importantly the catalytic graphitization step. Our data demonstrates that nitrogen inhibits graphitization but that some nitrogen survives the catalytic graphitization process to become incorporated into various chemical environments in the carbon product.
KW - Graphitization
KW - Nanoparticles
KW - Nanocomposite
KW - Porous carbon
KW - Nitrogen
KW - Scattering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575351
DO - https://doi.org/10.1039/d3ma00039g
VL - 4
SP - 2070
EP - 2077
PB - Royal Society of Chemistry
AN - OPUS4-57535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - Extending Bio-SAXS measurements of Single-Stranded DNA-Binding Proteins: Radiation Protection of G5P by Cosolutes
N2 - Small-angle X-ray scattering (SAXS) can be used for structural de- termination of biological macromolecules and polymers in their na- tive states. To improve the reliability of such experiments, the re- duction of radiation damage occurring from exposure to X-rays is needed.One method, is the use of scavenger molecules that protect macromolecules against radicals produced by radiation exposure.In this study we investigate the feasibility to apply the compatible solute, osmolyte and radiation protector Ectoine (THP(B)) as a scavenger throughout SAXS measurements of single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). Therefore we monitor the radiation induced changes of G5P during bio-SAXS. The resulting microscopic energy-damage relation was determined by particle scattering simu- lations with TOPAS/Geant4. The results are interpreted in terms of radical scavenging as well as post-irradiation effects, related to preferential-exclusion from the protein surface. Thus, Ectoine provides an non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies.
T2 - MultiChem Conference 2023
CY - Prague, Czech Republic
DA - 26.04.2023
KW - Bio-SAXS
KW - BioSAXS
KW - Compatible solute
KW - Cosolute
KW - DNA
KW - Dosimetry
KW - Ectoin
KW - Ectoine
KW - Ectoin
KW - G5P
KW - GVP
KW - Geant4
KW - Geant4-DNA
KW - Gene five protein
KW - Hydroxyectoine
KW - Ionizing radiation damage
KW - LEE
KW - McSAS3
KW - Microdosimetry
KW - Monte-Carlo simulations
KW - OH Radical
KW - OH radical scavenger
KW - Osmolyte
KW - Particle scattering simulations
KW - Protein
KW - Protein unfolding
KW - Proteins
KW - ROS
KW - Radiation damage
KW - Radical Scavenger
KW - Radical scavenger
KW - SAXS
KW - Single-stranded DNA-binding proteins
KW - Small-angle xray scattering
KW - Topas
KW - Topas-MC
KW - Topas-nBio
KW - X-ray scattering
KW - ssDNA
KW - Median lethal energy deposit
PY - 2023
AN - OPUS4-57407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
T1 - Electric Safety Interlock
N2 - This interlock is designed to prevent electrical shock from high voltage (>60V) equipment.
While the general safety interlock can be generically applied, this particular example employs an external vacuum-activated switch. It is for safeguarding human operations inside a vacuum sample chamber while the chamber doors are open. The circuit is closed (output is active) when a sufficient level of vacuum is reached, i.e. when all accessible openings are necessarily closed.
The initial application is to interrupt power to a 220V, 250W heating cartridge (itself mounted inside a small sample holder with potentially exposed contacts) when the sample chamber is open.
The external circuit can be modified to use different interlock mechanisms as needed. Note that the external interlock circuit is only a single circuit (with two signal lines) and thus is not protected against external shorts.
To accomodate a range of safety interlocks, the 4-pin M12 connector is wired as follows: Pin 1 (Brown): +24V for power supply, max current 0.6A Pin 2 (White): Safety interlock system signal 1 (0 or 24V) Pin 3 (Blue) : Safety interlock system signal 2 (0 or 24V) Pin 4 (Black): 0V for power supply
The safety is interlocked (output active) when both signal pins are set high (24V), with sufficient current to activate the two relays. Pin 1 and 4 can be used to power safety hardware (such as light curtains or proximity detectors) with 24VDC up to a current of 0.6A. A larger power supply can be installed when higher currents are needed, while staying within the current limits imposed by the wiring cross-section.
KW - Electric Safety Interlock
KW - MOUSE
KW - 60-230V
PY - 2023
DO - https://doi.org/10.6084/m9.figshare.22265920.v1
PB - Digital Science
CY - Cambridge, MA, USA
AN - OPUS4-57138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - X-ray Scattering USAXS/SAXS/WAXS (/XRD/PDF)
N2 - A ten minute introduction to the technique of X-ray scattering. This talk discusses the foundation and the resulting morphological parameters that can be obtained from the technique. The talk is prepared for discussion within the framework of the OECD REACH guideline for nanomaterials.
T2 - Digitaler Info-Tag "Nano or not Nano"
CY - Berlin, Germany
DA - 16.02.2023
KW - X-ray scattering
KW - BAM Academy
KW - SAXS
KW - XRD
KW - WAXS
KW - Nanomaterial
KW - REACH
KW - OECD
KW - Guideline
PY - 2023
AN - OPUS4-57013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Wetzel, Annica
A1 - Oczan, Ozlem
A1 - Nietzke, Jonathan
A1 - Richter, Tim
A1 - Schröpfer, Dirk
T1 - Hydrogen diffusion and local Volta potential in high- and medium-entropy alloys
N2 - High-entropy alloys (HEAs) are characterized by a solid solution of minimum five and medium-entropy alloys (MEAs) of minimum three principal alloying elements in equiatomic proportions. They show exceptional application properties, such as high-strength and ductility or corrosion resistance. Future HEA/MEA-components could be exposed to hydrogen containing environments like vessels for cryogenic or high-pressure storage where the hydrogen absorption and diffusion in these materials is of interest. In our study, we investigated the HEA Co20Cr20Fe20Mn20Ni20 and the MEA Co33.3Cr33.3Ni33.3. For hydrogen ingress, cathodic charging was applied and diffusion kinetic was measured by high-resolution thermal desorption spectros-copy using different heating rates up to 0.250 K/s. Peak deconvolution resulted in high-temperature desorption peaks and hydrogen trapping above 280 °C. A total hydrogen concentration > 40 ppm was identified for the MEA and > 100 ppm for HEA. This indicates two important effects: (1) delayed hydrogen diffusion and (2) considerable amount of trapped hydrogen that must be anticipated for hydrogen assisted cracking phenomenon. Local electrochemical Volta potential maps had been measured for the hydrogen free condition by means of high-resolution Scanning Kelvin Probe Force Microscopy (SKPFM).
T2 - Symposium on Materials and Joining Technology
CY - Online meeting
DA - 07.09.2020
KW - Hydrogen
KW - High-entropy alloy
KW - Diffusion
KW - Scanning kelvin probe force microscopy
KW - Corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511684
DO - https://doi.org/10.1088/1757-899X/882/1/012015
VL - 882
SP - 1
EP - 15
PB - IOP Publishing
CY - Bristol
AN - OPUS4-51168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Börner, Andreas
T1 - Influence of modern machining processes on the surface integrity of high-entropy alloys
N2 - High Entropy Alloys (HEAs) are a recent class of materials. In contrast to conventional alloys, HEAs consist of five alloying elements in equiatomic equilibrium. The high entropy effect is due, among other things, to the increased configuration entropy, which promotes solid solution formation. Many HEAs have enormous application potential due to excellent structural property combinations from very low to high temperatures. For the introduction of HEAs in real components, however, the question of the applicability of machining production technologies for component manufacture is of central importance. This has so far received Little attention in global materials research. Reliable and safe processing is essential for the demand of economical component production for potential areas of application, e.g. in power plant technology.
For metals, milling is the standard machining process. This article presents the results of machining analyses. It focuses on the surface integrity resulting from the milling process on a Co20Cr20Fe20Mn20Ni20-HEA. For this purpose, investigations were carried out using ball nose end milling tools for conventional milling process in comparison to an innovative hybrid process available at BAM Berlin, Ultrasonic-Assisted Milling (USAM). USAM promises a lower Degradation of the surface properties due to lower loads on the workpiece surface during machining.
For this purpose, basic milling parameters (cutting speed and tooth feed) were systematically varied and cutting forces were measured during the milling experiments. The subsequent Analysis of these forces allows an understanding of the mechanical loads acting on the tool and component surface. These loads cause topographical, mechanical and microstructural influences on the surface and consequently on the surface integrity. For their characterization, light and scanning electron microscopy were used, and the roughness and residual stresses via X-ray diffraction were measured. The results indicate significant advantages using USAM, especially due to reduced cutting forces compared to the conventional milling process. This causes lower mechanical loads on the tool and surface, combined with lower tensile residual stresses on and below the surface, and ultimately results in a significantly enhanced surface integrity.
T2 - Symposium on Materials and Joining Magdeburg 2020
CY - Online meeting
DA - 07.09.2020
KW - High entropy alloy
KW - Machining
KW - Ultrasonic machining
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512958
DO - https://doi.org/10.1088/1757-899X/882/1/012016
VL - 882
IS - 012016
SP - 1
EP - 11
PB - Institute of Physics
CY - London
AN - OPUS4-51295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Richter, Tim
A1 - Mente, Tobias
A1 - Mayr, P
A1 - Nitsche, A
T1 - Hydrogen effect on mechanical properties and cracking of creep‑resistant 9% Cr P92 steel and P91 weld metal
N2 - Martensitic 9% Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen-assisted cracking. The focus of this study was the microstructure and heat treatment efect on the mechanical properties of P92 base material and P91 multi-layer weld metal in both as-welded and post weld heat treated (PWHT) condition. Tensile tests with hydrogen free reference samples and electrochemically hydrogen charged samples were carried out; the mechanical properties were assessed and supported by detailed fractographic analysis. Finally, a hydrogen and microstructure-dependent fracture criterion is established. All investigated microstructures showed a hydrogen-infuenced degradation of the mechanical properties compared to the hydrogen-free reference samples. The as-welded martensitic P91 weld metal had the highest degree of degradation in the presence of hydrogen. The P91 PWHT weld metal and the P92 base material had comparable properties. From that point of view, a signifcantly increased risk for hydrogen-assisted cold cracking during welding fabrication of P91 weld joints must be considered before any heat treatment is conducted.
T2 - IIW Annual Assembly, Meeting of Commission IX-C
CY - Tokyo, Japan
DA - 16.07.2022
KW - Creep-resisting materials
KW - Welding
KW - Hydrogen assisted cracking
KW - Hydrogen embrittlement
KW - Mechanical properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564070
DO - https://doi.org/10.1007/s40194-022-01410-5
SN - 0043-2288
SP - 1
EP - 12
PB - Springer Nature
CY - Basel (CH)
AN - OPUS4-56407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buzolin, R. H.
A1 - Richter, Tim
A1 - Pixner, F.
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Enzinger, N.
T1 - Microstructure characterisation of multi-principal element alloys welds produced by electron beam welding
N2 - This work explores the feasibility of producing bead-on-plate welds of a CrCoNi medium entropy alloy and a CrMnFeCoNi high entropy alloy using electron beam welding. The alloys were welded in two states: one in an as-cold-rolled condition and the other in an annealed condition. In addition, the materials are welded with two different parameters. The FCC microstructure of the welds is investigated using scanning electron microscopy assisted by energy-dispersive X-ray spectroscopy and electron-backscattered diffraction. The impact of the weld on the microstructure is discussed. The heat-affected zone is negligible for the annealed condition of both medium and high entropy alloys since there is no driving force for recrystallisation and the exposure time to high temperature is insufficient for grain coarsening. The texture formed in the fusion zone is also discussed and compared to the texture in the base metal and the heat-affected zone. Although the grain growth along the (100) crystallographic direction is preferential in all cases, the crystallographic texture type differs from each weld. Higher hardness values are measured in the medium entropy alloy’s base metal and fusion zone than in the high entropy alloy.
KW - Multi-principal element alloy
KW - Electron backscattered diffraction
KW - Electron beam welding
KW - High-entropy alloy
KW - Microstructure characterization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568129
DO - https://doi.org/10.1016/j.matdes.2023.111609
SN - 1873-4197
VL - 225
SP - 1
EP - 14
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-56812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
T1 - Residual stresses in a high- and a medium-entropy alloy due to TIG and friction stir welding
N2 - The new alloying concept of multi-element systems with defined entropy (HEA—high-entropy alloy; MEA—medium-entropy alloy) is gaining increasing importance in materials research. Significantly improved properties or combinations of properties are shown by some HEA/MEA systems. Thus, primarily the production and resulting microstructures of HEA, as well as its properties, have been investigated so far. Furthermore, processing is a main issue in transferring HEA systems from the laboratory to real components. Since welding is the most important joining process for metals, it is crucial to investigate the influence of welding to guarantee component integrity. Welding leads to residual stresses, which significantly affect the component integrity. Hence, the focus of this study is the residual stress formation and distribution in a CoCrFeMnNi HEA and ternary CoCrNi MEA using two different welding processes: tungsten inert gas (TIG) welding and solid-state friction stir welding (FSW). As a pathway for the application of HEA in this investigation, for the first time, residual stress analyses in realistic near-component specimens were performed. The residual stresses were determined by X-ray diffraction (XRD) on the surfaces of top and root weld side. The results were correlated with the local welding microstructures. The results show that both FSW and TIG generate significant tensile residual stresses on the weld surfaces in, and transverse to, the welding direction. In the case of FSW of the CoCrFeMnNi HEA, the longitudinal residual stresses are in the range of the yield strength of approx. 260 MPa in the weld zone.
KW - High entropy alloy
KW - Welding
KW - Residual stresses
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567039
DO - https://doi.org/10.3390/jmmp6060147
SN - 2504-4494
VL - 6
IS - 6
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-56703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Reimagining user-driven science
N2 - The materials scientists we work with do not want (or need) to learn the ways of the scatterer; they are primarily interested in obtaining trustworthy, authoritative answers. In particular, they need structural understanding in light of the wider framework of their experiment(s). Our interest, therefore, lies in helping them attain this this interconnected understanding, while using such investigations to further hone our methodology to approximate perfection.
While perfection is by definition an unattainable goal, we have spent the last 15+ years exploring and expanding on many of its constituent aspects (often together with likeminded people) [1]. These aspects include:
developing various visualization and simulation tools,
deconstructing data corrections and uncertainty estimation,
advancing analysis methods,
quantifying questions on traceability, documentation,
reproducible automation of synthesis-, measurement- and data pipelines,
data visualization, exploration and education,
and many more…
As we explored these individual aspects, it has become clear that high quality output demands involving ourselves in the entire experimental workflow, with all associated aspects. This allows you to establish trustworthy links between parameters, structure, and performance. Through multiple cross-checks and validations, we can furthermore assign a degree of confidence to our findings. This is what we call the holistic approach.
This talk will briefly define perfection in scattering experiments, expand on the holistic approach, and show examples to demonstrate its benefits.
T2 - Invited talk - special event
CY - Trieste, Italy
DA - 15.05.2025
KW - X-ray scattering
KW - Holistic experiments
KW - Laboratory management
KW - Laboratory automation
KW - Data stewardship
KW - User support
PY - 2025
AN - OPUS4-63372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - and now it's bigger…: setting up for large scale experimentation
N2 - In our laboratory, we rely heavily on automation for synthesis and measurement. Done right, automation can deliver reliable quantities of excruciatingly detailed data, produced in a reproducible and traceable way. This data then needs sorting and organising, and a good structure of metadata is a good start to long-lasting data.
This metadata collection is an essential part of our “holistic experimentation”-approach. In this approach, we try to ensure that all aspects of the experimental chain are performed to a high standard, so that experimental integrity is maintained. In other words: as a failure in one of the components of the chain can make an entire experiment worthless, we must ensure each component is done (and documented) well.
In this talk, we show how we 1) synthesise well-documented sample series, 2) apply a complete end-to-end X-ray scattering characterisation methodology to those samples, and 3) can link the data from the synthesis to the structural details obtained from the scattering experiments in a visual dashboard. Furthermore, we will show examples on how data can be organised in hierarchical structures in HDF5-based datafiles, and how this helps move towards more trustworthy, traceable science.
T2 - Future Labs Live 2025
CY - Basel, Switzerland
DA - 27.05.2025
KW - Lab automation
KW - Holistic experiments
KW - Synthesis
KW - Traceability
KW - Data stewardship
PY - 2025
AN - OPUS4-63373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monroy, José del Refugio
A1 - Deshpande, Tejas
A1 - Schlecht, Joël
A1 - Douglas, Clara
A1 - Stirling, Robbie
A1 - Grabicki, Niklas
A1 - Smales, Glen Jacob
A1 - Kochovski, Zdravko
A1 - Fabozzi, Filippo Giovanni
A1 - Hecht, Stefan
A1 - Feldmann, Sascha
A1 - Dumele, Oliver
T1 - Homochiral versus racemic 2D covalent organic frameworks
N2 - The synthesis of homochiral two-dimensional covalent organic frameworks (2D COFs) from chiral π-conjugated building blocks is challenging, as chiral units often lead to misaligned stacking interactions. In this work, we introduce helical chirality into 2D COFs using configurationally stable enantiopure and racemic [5]helicenes as linkers in the backbone of 2D [5]HeliCOFs as powders and films. Through condensation with 1,3,5-triformylbenzene (TFB) or 1,3,5-triformylphloroglucinol (TFP), our approach enables the efficient formation of a set of homochiral and racemic 2D [5]HeliCOFs. The resulting carbon-based crystalline and porous frameworks exhibit distinct structural features and different properties between homochiral and racemic counterparts. Propagation of helical chirality into the backbone of the crystalline frameworks leads to the observation of advanced chiroptical properties in the far-red visible spectrum, along with a less compact structure compared with the racemic frameworks. Homogeneous thin films of [5]HeliCOFs disclosed photoluminescent properties arising from the controlled growth of highly ordered π-conjugated lattices. The present study offers insight into general chiral framework formation and extends the Liebisch−Wallach rule to 2D COFs.
KW - Chirality
KW - Covalent organic frameworks
KW - Diffraction
KW - Lattices
KW - Thin films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633755
DO - https://doi.org/10.1021/jacs.5c01004
SN - 0002-7863
VL - 147
IS - 21
SP - 17750
EP - 17763
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-63375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Vereinfachte Prüfmethode zur Bewertung der Gefahr wasserstoffunterstützter Kaltrisse (HACC) beim Lichtbogenschweißen hochfester Stähle
N2 - Die Präsentation gibt einen Kurzüberblick über die Versuchsmethodik und den erreichten Projektfortschritt des IGF-Projektes 01IF22624N bzw. DVS-Nr. 01.3410. Ziel der Untersuchungen ist eine Methodik für eine vereinfachte Probenform zur Bewertung der Kaltrissanfälligkeit durch Wasserstoff bei hochfesten, geschweißten Stählen. Dazu wird ISO 3690 (Quantifizierung des H-Gehaltes) mit direkt prüfbaren Querzugproben kombiniert, die die realistische Bewertung der Schweißnaht unter industriepraktischen Parametern ermöglicht.
T2 - Sitzung des NA 092-00-05 GA Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)
CY - Online meeting
DA - 20.03.2025
KW - Schweißnaht
KW - Kaltrissbildung
KW - Wasserstoff
KW - Prüfung
KW - ISO 3690
PY - 2025
AN - OPUS4-62759
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Boschmann Käthler, C.
A1 - Ebell, Gino
A1 - Keßler, S.
A1 - Schiegg, Y.
A1 - Dauberschmidt, C.
A1 - Angst, U. M.
T1 - A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete - Particular consideration of 12% chromium steel
N2 - The critical chloride content Ccrit is an indicator of the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content Ccrit of mild and alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests employing more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, against the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing.
KW - Chloride‐induced corrosion
KW - Critical chloride content
KW - Reinforced concrete
KW - Testing methods
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628485
DO - https://doi.org/10.1002/maco.202112826
SN - 0947-5117
VL - 73
IS - 3
SP - 306
EP - 325
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-62848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aliyah, K.
A1 - Prehal, C.
A1 - Diercks, J. S.
A1 - Diklić, N.
A1 - Xu, L.
A1 - Ünsal, S.
A1 - Appel, C.
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Guizar-Sicairos, M.
A1 - Herranz, J.
A1 - Gubler, L.
A1 - Büchi, F. N.
A1 - Eller, J.
T1 - Quantification of PEFC Catalyst Layer Saturation via In Silico, Ex Situ, and In Situ Small-Angle X-ray Scattering
N2 - The complex nature of liquid water saturation of polymer electrolyte fuel cell (PEFC) catalyst layers (CLs) greatly affects the device performance. To investigate this problem, we present a method to quantify the presence of liquid water in a PEFC CL using small-angle X-ray scattering (SAXS). This method leverages the differences in electron densities between the solid catalyst matrix and the liquid water filled pores of the CL under both dry and wet conditions. This approach is validated using ex situ wetting experiments, which aid the study of the transient saturation of a CL in a flow cell configuration in situ. The azimuthally integrated scattering data are fitted using 3D morphology models of the CL under dry conditions. Different wetting scenarios are realized in silico, and the corresponding SAXS data are numerically simulated by a direct 3D Fourier transformation. The simulated SAXS profiles of the different wetting scenarios are used to interpret the measured SAXS data which allows the derivation of the most probable wetting mechanism within a flow cell electrode.
KW - Polymer electrolyte fuel cell
KW - Water management
KW - Catalyst layer
KW - Representative morphology modeling
KW - Small-angle X-ray scattering
KW - MOUSE
KW - SAXS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575973
DO - https://doi.org/10.1021/acsami.3c00420
SN - 1944-8244
VL - 15
IS - 22
SP - 26538
EP - 26553
PB - ACS Publications
AN - OPUS4-57597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
T1 - Small-angle scattering data analysis round robin dataset - Original for participants
N2 - These are four datasets that were made available to the participants of the Small-angle Scattering data analysis round robin. The intent was to find out how comparable results from different researchers are, who analyse exactly the same processed, corrected dataset.
In this repository, there are:
1) a PDF document with more details for the study,
2) the datasets for people to try and fit,
3) an Excel spreadsheet to document the results.
Datasets 1 and 2 were modified from: Deumer, Jerome, & Gollwitzer, Christian. (2022). npSize_SAXS_data_PTB (Version 5) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.5886834
Datasets 3 and 4 were collected in-house on the MOUSE instrument.
KW - Round robin
KW - SAXS
KW - Small angle scattering
KW - SANS
KW - X-ray
KW - Neutron
KW - Human factor
KW - Data analysis
KW - Data fitting
KW - Human influence
PY - 2023
DO - https://doi.org/10.5281/zenodo.7506365
PB - Zenodo
CY - Geneva
AN - OPUS4-56799
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
T1 - McSAS3
N2 - McSAS3 is a refactored version of the original McSAS (see DOI 10.1107/S1600576715007347). This software fits scattering patterns to obtain size distributions without assumptions on the size distribution form. The refactored version has some neat features:
- Multiprocessing is included, spread out over as many cores as number of repetitions!
- Full state of the optimization is stored in an organized HDF5 state file.
- Histogramming is separate from optimization and a result can be re-histogrammed as many times as desired.
- SasModels allow a wide range of models to be used
- If SasModels does not work (e.g. because of gcc compiler issues on Windows or Mac), an internal sphere model is supplied
- Simulated data of the scattering of a special shape can also be used as a McSAS fitting model. Your models are infinite!
- 2D fitting also works.
KW - X-ray scattering
KW - Polydispersity
KW - Monte carlo
KW - Scattering pattern analysis
KW - Analysis approach
KW - Neutron scattering
KW - Automation
KW - Command line
PY - 2023
DO - https://doi.org/10.6084/m9.figshare.21814128.v1
PB - Digital Science
CY - Cambridge, MA, USA
AN - OPUS4-56787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
T1 - X-ray scattering Datasets of gold and silver nanoparticle composites, relating to the publication "Gold and silver dichroic nanocomposite in the quest for 3D printing the Lycurgus cup"
N2 - Wide-range X-ray scattering datasets and analyses for all samples described in the 2020 publication "Gold and silver dichroic nanocomposite in the quest for 3D printing the Lycurgus cup". These datasets are composed by combining multiple small-angle x-ray scattering and wide-angle x-ray scattering curves into a single dataset. They have been analyzed using McSAS to extract polydispersities and volume fractions. They have been collected using the MOUSE project (instrument and methodology).
KW - X-ray scattering
KW - MOUSE
KW - Saxs
KW - Waxs
KW - Analyses
KW - Datasets
PY - 2022
DO - https://doi.org/10.5281/zenodo.7193859
PB - Zenodo
CY - Geneva
AN - OPUS4-55979
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - The human factor: A round robin study on the variation in data analyses
N2 - How much do we, the small-angle scatterers, influence the results of an investigation? What uncertainty do we add by our human diversity in thoughts and approaches, and is this significant compared to the uncertainty from the instrumental measurement factors?
After our previous Round Robin on data collection, we know that many laboratories can collect reasonably consistent small-angle scattering data on easy samples. To investigate the next, human component, we compiled four existing datasets from globular (roughly spherical) scatterers, each exhibiting a common complication, and asked the participants to apply their usual methods and toolset to the quantification of the results (https://lookingatnothing.com/index.php/archives/3274).
Accompanying the datasets was a modicum of accompanying information to help with the interpretation of the data, similar to what we normally receive from our collaborators. More than 30 participants reported back with volume fractions, mean sizes and size distribution widths of the particle populations in the samples, as well as information on their self-assessed level of experience and years in the field.
While the Round Robin is still underway (until the 25th of April, 2022), the initial results already show significant spread in the results. Some of these are due to the variety in interpretation of the meaning of the requested parameters, as well as simple human errors, both of which are easy to correct for. Nevertheless, even after correcting for these differences in understanding, a significant spread remains. This highlights an urgent challenge to our community: how can we better help ourselves and our colleagues obtain more reliable results, how could we take the human factor out of the equation, so to speak?
In this talk, we will introduce the four datasets, their origins and challenges. Hot off the press, we will summarize the anonymized, quantified results of the Data Analysis Round Robin. (Incidentally, we will also see if a correlation exists between experience and proximity of the result to the median). Lastly, potential avenues for improving our field will be offered based on the findings, ranging from low-effort yet somehow controversial improvements, to high-effort foundational considerations.
T2 - International Small-Angle Scattering Conference (SAS2022)
CY - Campinas, Brazil
DA - 11.09.2022
KW - Round robin
KW - Data analysis
KW - Small angle scattering
KW - Nanomaterials
KW - MOUSE
KW - Interlaboratory comparison
KW - Intercomparability
KW - Reliability
KW - Data analysis round robin
KW - Large number of participants
PY - 2022
AN - OPUS4-55762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - X-ray scattering for nanostructure quantification, and the quest for the perfect experiment
N2 - Measuring an X-ray scattering pattern is relatively easy, but measuring a steady stream of high-quality, useful patterns requires significant effort and good laboratory organization.
Such laboratory organization can help address the reproducibility crisis in science, and easily multiply the scientific output of a laboratory, while greatly elevating the quality of the measurements. We have demonstrated this for small- and wide-angle X-ray scattering in the MOUSE project (Methodology Optimization for Ultrafine Structure Exploration).
With the MOUSE, we have combined a comprehensive and highly automated laboratory workflow with a heavily modified X-ray scattering instrument. This combination allows us to collect fully traceable scattering data, within a well-documented, FAIR-compliant data flow (akin to what is found at the more automated synchrotron beamlines). With two full-time researchers, our lab collects and interprets thousands of datasets, on hundreds of samples, for dozens of projects per year, supporting many users along the entire process from sample selection and preparation, to the analysis of the resulting data.
This talk will briefly introduce the foundations of X-ray scattering, present the MOUSE project, and will highlight the proven utility of the methodology for materials science. Upgrades to the methodology will also be discussed, as well as possible avenues for transferring this holistic methodology to other instruments
T2 - SNI 2022
CY - Berlin, Germany
DA - 05.09.2022
KW - Methodology
KW - X-ray scattering
KW - Laboratory management
KW - Instrumentation utilization
KW - MOUSE
KW - SAXS
KW - WAXS
KW - Automation
PY - 2022
AN - OPUS4-55760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Smales, Glen Jacob
A1 - Hahn, Marc Benjamin
A1 - Hallier, Dorothea C.
A1 - Seitz, H.
T1 - X-ray scattering datasets and simulations associated with the publication "Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine"
N2 - This dataset contains the processed and analysed small-angle X-ray scattering data associated with all samples from the publications "Bio-SAXS of Single-Stranded DNA-Binding Proteins: Radiation Protection by the Compatible Solute Ectoine" (https://doi.org/10.1039/D2CP05053F).
Files associated with McSAS3 analyses are included, alongside the relevant SAXS data, with datasets labelled in accordance to the protein (G5P), its concentration (1, 2 or 4 mg/mL), and if Ectoine is present (Ect) or absent (Pure). PEPSIsaxs simulations of the GVP monomer (PDB structure: 1GV5 ) and dimer are also included.
TOPAS-bioSAXS-dosimetry extension for TOPAS-nBio based particle scattering simulations can be obtained from https://github.com/MarcBHahn/TOPAS-bioSAXS-dosimetry which is further described in https://doi.org/10.26272/opus4-55751.
This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under grant number 442240902 (HA 8528/2-1 and SE 2999/2-1). We acknowledge Diamond Light Source for time on Beamline B21 under Proposal SM29806. This work has been supported by iNEXT-Discovery, grant number 871037, funded by the Horizon 2020 program of the European Commission.
KW - SAXS
KW - Radiation protection
KW - Microdosimetry
KW - G5P
KW - Ectoine
KW - DNA-Binding protein
PY - 2023
DO - https://doi.org/10.5281/zenodo.7515394
PB - Zenodo
CY - Geneva
AN - OPUS4-56811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Richter, Tim
T1 - Hydrogen diffusion and desorption characteristics of a CoCrFeMnNi high entropy and a CoCrNi medium entropy alloy
N2 - High-entropy alloys (HEAs) are innovative high-performance materials that have attracted more and more research attention. HEAs are characterized by a solid solution of typically five equiatomic metallic elements. In addition, medium-entropy alloys (MEA, with three elements) are of interest and become more and more important. Depending on the alloy concept, HEAs and MEAs show exceptional mechanical properties, especially high-strength and ductility combinations at both cryogenic and elevated temperatures combined with excellent corrosion resistance. Future structural HEA/MEA components can be exposed to potential applications with hydrogen containing environments like high-temperature water in pressurized nuclear reactors or aerospace structures. Other potential applications could be in materials for vessel walls in the field of cryogenic and high-pressure hydrogen storage. So far, the susceptibility of HEAs/MEAs to hydrogen assisted cracking (if any) and the hydrogen diffusion is not investigated in detail yet and can limit or extend possible applications of HEA/MEA as structural materials. In our work, we focused on the hydrogen absorption, diffusion, and distribution in a HEA (CoCrFeMnNi the original Cantor-alloy) and a MEA (CoCrNi). Cathodic hydrogen charging was carried out for the hydrogen ingress, and thermal desorption analysis (TDA) revealed complex hydrogen trapping in both alloy types up to 300 °C. The absorbed total hydrogen concentrations were > 100 ppm for the HEA and > 40 ppm for MEA. In addition, the assessment of the peak deconvolution is not trivial and must consider both experimental and microstructure influences.
T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022
CY - Ghent, Belgium
DA - 11.10.2022
KW - Hydrogen
KW - High-entropy alloy
KW - Multiple principal element alloy
KW - Thermal desorption analysis
KW - Diffusion
PY - 2022
SP - 1
EP - 11
CY - Ghent, Belgium
AN - OPUS4-56076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, Daniel
A1 - Bertovic, Marija
T1 - Expertise oder KI – Was hilft uns in der ZfP'?
N2 - Die zunehmende Integration von Automatisierung und KI in die zerstörungsfreie Prüfung (ZfP) verändert nicht nur die Prüfprozesse selbst, sondern auch die Art und Weise, wie Entscheidungen getroffen werden. Während technische Systeme die Fehleranfälligkeit verringern und die Datenverarbeitung unterstützen können, bleibt die letztendliche Verantwortung beim Menschen. Dieser Beitrag untersucht die Rolle der Intuition in der Entscheidungsfindung und analysiert typische Fehleinschätzungen mithilfe der Prospekttheorie und Erkenntnissen aus der kognitiven Psychologie. Zudem wird aufgezeigt, wie fundierte Entscheidungen in KI-gestützten ZfP Prozessen unterstützt werden können – durch Schulung, erklärbare Systeme, nutzerzentrierte Gestaltung, geeignete Metriken und eine gezielte Aufgabenverteilung zwischen Mensch und Technik.
T2 - DGZfP-Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - Zerstörungsfreie Prüfung
KW - Künstliche Intelligenz
KW - Entscheidungsfindung
KW - Mensch-Maschine-Interaktion
KW - Human Factors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634070
DO - https://doi.org/10.58286/31237
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-63407
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, Daniel
A1 - Bertovic, Marija
T1 - Expertise oder KI – Was hilft uns in der ZfP'?
N2 - Die zunehmende Integration von Automatisierung und KI in die zerstörungsfreie Prüfung (ZfP) verändert nicht nur die Prüfprozesse selbst, sondern auch die Art und Weise, wie Entscheidungen getroffen werden. Während technische Systeme die Fehleranfälligkeit verringern und die Datenverarbeitung unterstützen können, bleibt die letztendliche Verantwortung beim Menschen. Dieser Beitrag untersucht die Rolle der Intuition in der Entscheidungsfindung und analysiert typische Fehleinschätzungen mithilfe der Prospekttheorie und Erkenntnissen aus der kognitiven Psychologie. Zudem wird aufgezeigt, wie fundierte Entscheidungen in KI-gestützten ZfPProzessen unterstützt werden können – durch Schulung, erklärbare Systeme, nutzerzentrierte Gestaltung, geeignete Metriken und eine gezielte Aufgabenverteilung zwischen Mensch und Technik.
T2 - DGZfP-Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - Zerstörungsfreie Prüfung
KW - Artificial intelligence
KW - Entscheidungsfindung
KW - Mensch-Maschine-Interaktion
KW - Human Factors
PY - 2025
AN - OPUS4-63408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valet, Svenja
A1 - Bohlmann, Tatjana
A1 - Burkert, Andreas
A1 - Ebell, Gino
T1 - Zinc acetate containing gel pads for electrochemical measurements of Zn samples
N2 - Agar gel pads have been used for electrochemical measurements for some time. For zinc in particular, a standard method for measuring the stability of the corrosion product layer is being established. The main interpretation factor is the corrosion product layer resistance RL, as it is easy to determine and interpret. A high corrosion product layer resistance indicates a high level of protection. However, it is not yet known how low the corrosion product layer resistance is for freshly produced zinc samples. As zinc is highly active, it reacts immediately with the environment to form a corrosion product layer, which affects the corrosion product layer resistance. The addition of zinc acetate to the agar gel pads prevents the formation of a surface layer and destroys existing ones.
This makes it possible to measure an almost corrosion product-free zinc surface. This is important in defining the range of corrosion product layer resistance for a protective surface.
KW - Electrochemistry
KW - General Chemical Engineering
KW - Analytical Chemistry
KW - Corrosion
KW - Zinc
KW - Korrosion
PY - 2023
DO - https://doi.org/10.1016/j.jelechem.2023.117814
SN - 1572-6657
VL - 948
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-59079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nietzke, Jonathan
T1 - Hydrogen diffusion and desorption characteristics of a CoCrFeMnNi high entropy and a CoCrNi medium entropy alloy
N2 - Future structural components made of the novel high-entropy (HEA) or medium-entropy alloys (MEA) components can be potentially exposed to hydrogen containing environments like high-temperature water in pressurized nuclear reactors or aerospace structures. Further applications are vessels wall materials for cryogenic or high-pressure hydrogen storage. So far, the susceptibility of HEA/MEAs to hydrogen assisted cracking (if any) and the hydrogen diffusion is not investigated in detail yet and can limit or extend possible applications of HEA/MEA as structural materials. In our work, we focused on the hydrogen absorption, diffusion, and distribution in a HEA (Co20Cr20Fe20Mn20Ni20, the original Cantor-alloy) and a MEA (Co33.3Cr33.3Ni33.3). Conventional cathodic hydrogen charging was carried out for the hydrogen ingress in the materials. Thermal desorption analysis (TDA) via carrier gas hot extraction with coupled mass spectrometry revealed complex hydrogen trapping in both alloy types up to 300 °C. The absorbed total hydrogen concentrations were ≥ 70 ppm for the HEA and approximately 40 ppm for the MEA-type. Although both materials have different chemical composition, the TDA spectra were comparable. In addition, it was shown that the consideration of the sample geometry is an important influence on the sample temperature. It decreases the effective applied heating rate, which must be anticipated for each hydrogen peak after deconvolution of the spectra. This increases the activation energy and shifts the peak to lower temperatures. As a result, microstructure effects can be separated from experimental boundary conditions like the concentration gradient due to the charging process and later thermal activation.
T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022
CY - Ghent, Belgium
DA - 11.10.2022
KW - High-entropy alloy
KW - Diffusion
KW - Hydrogen
KW - Thermal desorption analysis
KW - Trapping
PY - 2022
AN - OPUS4-56007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gupta, Kanhaiya
T1 - Microstructural fingerprinting of additively manufactured components prepared by PBF LB/M
N2 - Additive manufacturing (AM) is rapidly emerging from rapid prototyping to industrial production [1]. Thus, providing AM parts with a tagging feature that allows identification, like a fingerprint, can be crucial for logistics, certification, and anti-counterfeiting purposes since nearly any geometry can be produced by AM with stolen data or reverse engineering of an original product. However, the mechanical and functional properties of the replicated part may not be identical to the original ones and pose a safety risk [2].
Several methods are already available, which range from encasing a detector to leveraging the stochastic defects of AM parts for the identification, authentication, and traceability of AM components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface of the internal cavity of hollow components. Local manipulation of components may alter the properties. The external tagging features can be altered or even removed by post-processing treatments. Integrating electronic systems [4] in AM parts can be used to identify and authenticate components with complex or customized geometries. However, metal-based AM, especially in powder bed fusion (PBF-LB/M) techniques, has a strong shielding effect that interferes with the communication between the reader and the transponder.
Figure 1: Selection of the few most prominent pores sorted according to decreasing volume that are suitable for tagging and authentication.
Our work aims to provide a new methodology for the identification, authentication, and traceability of AM components using microstructural feathers in AM components without altering their properties. Further, we set various benchmark points that can be used in generating the fingerprints for both identification and authentication. This can help digitalize traceability information and tagging features via the link between the physical and cyber worlds through a deeper understanding of the printed object-tag-virtual twin integration.
T2 - MSE Konferennz
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Fingerprint
KW - Additive Manufacturing
KW - Computed tomography
PY - 2024
AN - OPUS4-62286
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Wire Arc Additive Manufacturing (WAAM) mit hochfesten Feinkornbaustählen
N2 - Die additive Verarbeitung hochfester Feinkornbaustähle mittels Wire Arc Additive Manufacturing (WAAM) ist ein komplexes, aber zugleich auch effizientes Verfahren, bei dem Werkstoff, Bauteilgeometrie und Schweißprozess gezielt aufeinander abgestimmt sein müssen. Ziel dieser Studie war es, einen Zusammenhang zwischen den Prozessparametern und der generierten Schichtgeometrie zu ermitteln. Dazu wurden definierte Referenzkörper mit einem robotergestützten Schweißsystem additiv gefertigt und hinsichtlich Schichthöhe, Wandstärke und Mikrostruktur analysiert. Fokus der Untersuchung waren sowohl konventionelle als auch für die WAAM-Fertigung speziell entwickelte hochfeste Schweißzusatzwerkstoffe. Die geometrischen Eigenschaften additiv gefertigter Bauteile lassen sich insbesondere durch die Faktoren Drahtvorschubgeschwindigkeit und Schweißgeschwindigkeit gezielt einstellen. Jedoch können diese Parameter nicht beliebig variiert werden, auch aufgrund der rheologischen Eigenschaften der Zusatzwerkstoffe. Zu hohe Streckenenergien führen zu lokalen Überhitzungen und Fehlstellen in der generierten Schicht. Undefinierte Fließ- und Erstarrungsvorgänge im überhitzten Bereich erschweren die maßhaltige Fertigung. Deshalb wird bei speziellen WAAM-Schweißdrähten das Fließverhalten gezielt modifiziert, sodass es über einen größeren Temperaturbereich hinweg konstant ist. Erst die Kenntnis über die komplexen Zusammenhänge zwischen den Prozessparametern und der Bauteilgeometrie ermöglicht die Erzeugung exakter Schichtmodelle für die additive Fertigung. Dies bildet die Grundlage für die Bearbeitung weiterer Fragestellungen auf dem Gebiet der additiven Fertigung mit hochfesten Zusatzwerkstoffen und insbesondere deren Anwendung in modernen hochfesten Bauteilen.
T2 - 41. Assistentenseminar Fügetechnik
CY - Magdeburg, Germany
DA - 03.09.2020
KW - Additiver Fertigung
KW - MSG-Schweißen
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Kaltrisssicherheit
PY - 2020
AN - OPUS4-56690
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meinel, Dietmar
T1 - Classic Materials Testing in the Light of CT
N2 - Currently, mandatory requirements and recommendations for the detection of irregularities in laser beam welded joints are based on classic micrographs as set out in the standard ISO 13919-1:2019. Compared to classic micrographs, computed tomography enables a non-destructive, three-dimensional and material-independent mode of operation, which delivers much more profound results. Even in building material testing, methods with limited informative value can be checked and supplemented by CT examinations.
T2 - 13th International Conference on Industrial Computed Tomography (iCT2024)
CY - Wels, Austria
DA - 06.02.2024
KW - Computed Tomography
KW - Additive Manufacturing
KW - Machine-Learning Segmentation
KW - Air Void System
PY - 2024
AN - OPUS4-59568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Dissimilar metal joints of multiple principal element alloys friction stir welded to conventional austenitic steel 304
N2 - Multiple principal element alloys (MPEA) represent a class of materials consisting of at least three alloying elements, each with 5 to 35 atomic %. The MPEAs encompass the so-called high-entropy (HEA) and medium-entropy alloys (MEAs) and are fundamentally different from conventional materials like the Fe-based steel. Within the last 20 years, highly innovative MPEA with individually adjustable properties for industrial applications were identified. However, the focus has been on pure material synthesis. With the increase in available material quantities, the focus is now on processing issues such as joining and welding. In that connection, the weldability of MPEAs has received very little attention so far and experience in dissimilar metal welds (DMWs) is lacking so far but. The present study summarizes comprehensive experimental results on the weldability of MPEA-DMWs and their resulting microstructure. For this purpose, two equiatomic MPEAs, CoCrFeMnNi (HEA) and CoCrNi (MEA) in cold-rolled and annealed conditions were joined by solid-state friction stir welding (FSW) to an austenitic stainless steel 316L. The DMWs showed very interesting microstructure features. In addition, the mechanical-technological properties were obtained by instrumented tensile tests, and the local straining was determined in-situ by digital image correlation (DIC). A significant influence of the FSW processing on the mechanical performance was identified,in terms of the formation of FSW-specific defects like whitebands or tunnel defects. The experiments proofed the general (but currently limited) FS weldability of the MPEAs to conventional austenitic steel grade AISI 304. This enables targeted further considerations of these highly innovative MPEAs.
T2 - AJP 2023: 3rd International Conference on Advanced Joining Processes 2023
CY - Braga, Portugal
DA - 19.10.2023
KW - Multi-principal element alloys
KW - Friction stir welding
KW - Dissimilar metal weld (DMW) joint
KW - Mechanical properties
KW - Digital image correlation (DIC)
PY - 2023
AN - OPUS4-58678
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Development of a component test for assessment of delayed hydrogen assisted cracking susceptibility of thick walled submerged arc welded high strength offshore steels
N2 - Offshore Wind Turbines (OWT) are a key factor in tomorrow's sustainable energy generation. The ever-increasing installation depth and weight of OWTs require suitable foundation concepts such as monopiles or tripods. Typically, mild steels such as S420ML are used with plate thicknesses of up to several hundred mm, resulting in high restraints in the welded joints. The large plate thickness requires high-efficiency welding processes such as submerged arc welding (SAW) with multiple wires. Due to the very high stiffness and plate thickness of the large-scale offshore structure, a susceptibility to time-delayed hydrogen assisted cracking (HAC) may occur. The evaluation of this crack susceptibility is very complex due to the component size and stiffness of real offshore structures. For this purpose, a near-component test geometry was developed to transfer the real stiffness conditions to laboratory (i.e. workshop) scale. The 350 kg mock-up studied consisted of heavy plates (thickness 50 mm, seam length 1,000 m) joined by a 22-pass submerged-arc weld. Additional stiffeners simulated the effect of high restraint or shrinkage restraint of the weld. Extreme scenarios of hydrogen absorption during welding were simulated by using flux in dry (HD < 5 ml/100g Fe) and wet (HD > 15 ml/100g Fe) conditions. Weld residual stresses were determined using a robotic X-ray diffractometer. Areas of critical tensile residual stress (at the level of the yield strength) were found in the weld metal and in the heat affected zone, suggesting that these weld sub-zones are the most critical in the case of hydrogen ingress. To identify possible delayed cracking, the welds were tested by phased array ultrasonic testing (PAUT) after welding, 6 h, 12 h, 24 h, and a maximum of 48 h. Summarized, no significant occurrence of HAC was detected, indicating the high crack resistance of the welded joint, i.e., a suitable combination of base material, welding consumable and parameters.
T2 - MSE 2024: International Materials Science and Engineering Congress
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Hydrogen
KW - Offshore wind turbine
KW - Component test
KW - Submerged arc welding
KW - Minimum waiting time
PY - 2024
AN - OPUS4-61154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Czeskleba, Denis
T1 - Investigation of the Stress Relief Cracking mechanism through the simulation of uniaxial stress conditions in the coarse grain HAZ of CrMoV-steel SAW joints
N2 - Creep-resistant steels such as the 13CrMoV9-10 used in pressure vessel construction, with wall thicknesses of 250 mm and above, are most commonly submerged arc welded (SAW). The characteristic high heat input during the SAW-process introduces very high, localized residual stresses, which can lead to stress relief cracking (SRC) if the mandatory post weld heat treatment (PWHT) of the welding joint is performed improperly. Current PWHT parameters, such as heating rate and holding time at a specific holding temperature are mostly based on both empirically experience and conventional free shrinking welding experiments to characterize the SRC-susceptibility of the weld. These cannot adequately depict the higher residual stresses caused by the structurally induced stiffness of the surrounding construction and its constraint on the thermal shrinkage of the weld. Nor do they consider the resulting metallurgic effects such as the growth of precipitates during the PWHT and the resulting differences in hardness of the grain boundaries or the premature aging via a dissimilar precipitation behavior. The effect of the heating rate of the PWHT on the SRC susceptibility has to date not been adequately studied either.
This study discusses the development of a repeatable, precise and time efficient methodology to study the effects of different stress levels and heating rates on the SRC susceptibility of the coarse grain heat affected zone (CGHAZ). For that purpose, samples were thermically treated to simulate a CGHAZ and subsequently exposed to representative levels of stress during PWHTs with defined parameters. The recorded stress and heating rate dependent strains were mathematically analyzed via curve tracing/ calculus to identify interdependent effects. This procedure facilitates the measurement of material characteristics such as carbide growth on grain boundaries at the µm-scale via an integrated value over the entire sample volume. The first and second derivate show a slight, precipitate dependent, increase in hardness of the sample, depending on the heating rate and applied stress. Additionally, the formation and growth of special carbides is well known to have a volumetric effect, which together with the material characterization and this new methodology is believed to generate an improved assessment of the SRC susceptibility of SAW microstructures of creep-resistant CrMoV steels. The main advantage of the suggested methodology is the material independence. It thus provides, a comparative value between welds under ideal conditions in the lab and real-world scenarios by including an idealized, simulated component rigidity.
T2 - IIW 2022
CY - Tokyo, Japan
DA - 16.07.2022
KW - Repair-welding
KW - High-strength steels
KW - Transient stresses
KW - Residual stresses
PY - 2022
AN - OPUS4-55441
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Einfluss der Zwischenlagenzeit und der Bauteilhöhe auf die resultierenden Eigenschaften laserstrahlgeschmolzener austenitischer Stahlbauteile
N2 - Das pulverbettbasierte selektive Laserstrahlschmelzen (engl. laser powder bed fusion, L-PBF) ist die am weitesten verbreitete additive Fertigungstechnologie für die Herstellung metallischer Komponenten. Unter der Vielzahl an Einflussfaktoren auf die Qualität und die mechanischen Eigenschaften von L PBF-Bauteilen hat die Zwischenlagenzeit (engl. inter layer time, ILT) bisher kaum Beachtung in der wissenschaftlichen Literatur gefunden, obwohl sie je nach Bauraumausnutzungsgrad stark variieren kann. In diesem Vortrag werden Ergebnisse einer Studie präsentiert, die den Einfluss der ILT in Kombination mit der Bauteilhöhe und unter Berücksichtigung verschiedener Volumenenergiedichten am Beispiel der austenitischen Stahllegierung AISI 316L untersucht. Die Fertigungsprozesse wurden in situ mittels Thermographiekamera überwacht, sodass Informationen über das Abkühlverhalten der Bauteile während des Prozesses gewonnen werden konnten. Es wurden signifikante Effekte der ILT und der Bauteilhöhe auf Wärmeakkumulation, Mikrostruktur, Schmelzbadgeometrie und Härte festgestellt. Ferner konnte ein Anstieg von Defektdichten bei einem gegenseitigen Wechselspiel aus Bauteilhöhe und ILT aufgezeigt werden. Die Zwischenlagenzeit wurde somit als kritischer Faktor für die L-PBF-Fertigung von Realbauteilen identifiziert.
T2 - DGM Fachtagung "Werkstoffe und Additive Fertigung"
CY - Online meeting
DA - 13.05.2020
KW - Laser Powder Bed Fusion
KW - Additive Fertigung
KW - Zwischenlagenzeit
KW - In-situ Monitoring
PY - 2020
AN - OPUS4-50788
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Griesche, Axel
T1 - Martensitumwandlung in situ analysiert mit Röntgenstrahlung
N2 - Die dehnungsinduzierte Martensitbildung wurde mittels Röntgen-Diffraktion und -Radiographie mit dem EDDI-Instrument am BESSY II in supermartensitischem Stahl mit Anlassaustenit untersucht. Die Bildung wird durch Wasserstoff im Gefüge unterdrückt. Die Duktilität von wasserstofffreiem SMSS korreliert mit dem Anteil an dehnungs-induziertem Martensit
T2 - Symposium on Materials and Joining Technology
CY - Online meeting
DA - 07.09.2020
KW - Wasserstoff
KW - Materialschädigung
KW - Materialschaedigung
KW - Synchrotron
PY - 2020
AN - OPUS4-51190
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schaupp, Thomas
A1 - Schröpfer, Dirk
A1 - Schröder, Nina
A1 - Kannengießer, Thomas
T1 - Einfluss von Konstruktion und Wasserstoff auf die Kaltrissbildung hochfester Feinkornbaustähle
N2 - Der konstruktive Leichtbau erfordert den zunehmenden Einsatz hochfester Feinkornbaustähle mit Streckgrenzen ≥ 690 MPa. Neben den durch die Wandstärkenreduzierung erreichbaren Einsparungen an Ressourcen und Fertigungszeit lässt sich eine weitere Minimierung der Schweißzeit und -kosten mittels abgesenkter Schweißnahtvolumina erreichen. Hierzu wurden moderne Lichtbogenprozesse, wie bspw. der modifizierte Sprühlichtbogen (Mod.SLB), mit erhöhter Abschmelzleistung entwickelt, mit denen auch enge Nahtspalte bzw. Nahtöffnungswinkel geschweißt werden können. Hochfeste Verbindungen unterliegen zunehmend erhöhten Anforderungen in Bezug auf die schweißtechnische Verarbeitung und der resultierenden Bauteilperformance und sicherheit. Dies gilt insbesondere beim Bauteilschweißen mittels solcher Hochleistungsverfahren in Verbindung mit engen Nahtspalten. In der vorliegenden Arbeit soll dieser Herausforderung durch Klärung der Einflüsse auf die Kaltrissbildung bei einem hochfesten Feinkornbau-stahl S960QL Rechnung getragen werden. Für die Kaltrissprüfung werden entsprechende adaptierte Proben analog dem selbstbeanspruchenden TEKKEN-Test verwendet und hinsichtlich Rissbildung, Gefüge, Gehalt an diffusiblem Wasserstoff und Eigenspannungen analysiert. Die Variation der Nahtöffnungswinkel der Prüfnähte erfolgt zwischen 30° und 60°. Zur Vermeidung wasserstoffunterstützter Kaltrissbildung wird die Wirksamkeit einer Nachwärmprozedur aus der Schweißwärme heraus untersucht. Als Ergebnis zeigen die Schweißgüter, die an reduziertem Nahtöffnungswinkel erzeugt wurden, im Mittel etwas höhere Wasserstoffkonzentrationen. Zudem ist an diesen Schweißgütern eine vermehrte Mikro- als auch Makrorissbildung festzustellen. An allen Proben, die nicht nachgewärmt wurden, treten Kerbrisse aufgrund von Kaltrissbildung auf, deren Vermeidung sich durch ein Nachwärmen unmittelbar nach dem Schweißen als besonders effektiv darstellte.
T2 - DVS Congress 2020 - Große Schweißtechnische Tagung
CY - Online meeting
DA - 14.09.2020
KW - Hochfester Feinkornbaustahl
KW - MAG-Schweißen
KW - Kaltriss
KW - Wasserstoff
KW - TEKKEN
PY - 2020
SN - 978-3-96144-098-6
VL - 365
SP - 564
EP - 570
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-51259
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Taparli, Ugur Alp
T1 - Online weld analysis by laser-induced breakdown spectroscopy (LIBS)
N2 - Principles of online weld inspection using laser-induced breakdown spectroscopy, inspection of stationary and bead-on-plate welds containing solidification cracks.
T2 - Symposium on Materials and Joining Technology
CY - Online meeting
DA - 07.09.2020
KW - Welding
KW - LIBS
KW - Austenitic stainless steel
KW - Metal vapor
KW - Hot cracking
PY - 2020
AN - OPUS4-51191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Influence of welding stresses on relaxation cracking during heat treatment of a creep-resistant 13CrMoV steel, Part III
N2 - Efficiency and flexibility are currently a major concern in the design of modern power plants and chemical processing facilities. The high requirements for economic profitability and in particular climate change neutrality are driving this development. Consequently, plant equipment and chemical reactor components are designed for higher operating pressure and temperature. Creep-resistant CrMo steels had been used as constructional materials for decades but came to operational limitations, for example the resistance against so-called high-temperature hydrogen attack in petrochemical reactors. For that purpose, 20 years ago V-modified CrMo steels had been developed for use in the petrochemical industry due to their very good creep-strength and hydrogen pressure resistance at elevated temperatures enabling long service life of the respective components. For example, the 13CrMoV9-10 steel is applicable for process temperatures of up to 482 °C and hydrogen pressures of up to 34.5 MPa.
Due to the large dimensions and wall thickness of the reactors (wall thickness up to 475 mm) and the special alloy concept, reliable weld manufacturing of the components is extremely challenging. First, low toughness and high strength of the weld joint in the as-welded condition are critical regarding weld cracking. High welding residual stresses are the result of the highly restrained shrinkage of the component welds. For this purpose, the entire component must be subjected to Post-Weld Heat Treatment (PWHT) after completion of the welding operation. The aim is to increase the toughness of the weld joints as well as to reduce the welding induced residual stresses. Before and during PWHT, extreme caution is required to prevent cracking. Unfortunately, V-modified CrMo steels possess an increased susceptibility to cracking during stress relaxation the so-called stress relief cracking (SRC).
Available literature studies have largely focused on thermal and metallurgical factors. However, little attention has been paid on the influence of the welding procedure on crack formation during PWHT considering actual manufacturing conditions. For that reason, we investigated in our previous studies (part I and II), the influence of heat control on the mechanical properties by simulating actual manufacturing conditions prevailing during the construction of petrochemical reactors using a special 3D- acting testing facility. The focus of part I was put on the influence of the welding heat control on mechanical stresses and the effect on cracking during PWHT. Part II was mainly dedicated to the metallurgical causes of SRC during PWHT and the interaction with the occurring mechanical stresses. It could be shown that not only high welding-induced stresses due to increased weld heat input cause higher susceptibility for SRC formation. It was further intensified by an altered precipitation behaviour in presence of mechanical stresses that are caused by the component related restraint. The present part III shows how residual stresses, which are present in such welded components and significantly influence the crack formation, can be transferred to the laboratory scale. As a result, the effect on the residual stresses on the SRC behaviour can be evaluated on simplified small-scale specimens instead of expensive mock-ups. For this purpose, experiments with test set-ups at different scales and under different rigidity conditions were designed and carried out.
T2 - IIW Annual Assembly, Meeting of Commission II-A
CY - Online meeting
DA - 20.07.2020
KW - Welding
KW - Creep-resistant steel
KW - Residual stresses
KW - Post weld heat treatment
KW - Stress relief cracking
PY - 2020
AN - OPUS4-51587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
A1 - Engelking, Lorenz
T1 - Bericht zum Fortschritt des laufenden Projekts: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehen die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die mit dem Forschungsvorhaben verbundenen Nutzen für KMU sind die Stärkung der Innovationsfähigkeit und der Wirtschaftlichkeit sowie die Erhöhung der Wettbewerbsfähigkeit. In AP-1 wurden erste Zerspanversuche am CoCr-Ausgangswerkstoff durchgeführt. Ziel der Versuche war in erster Linie die Identifikation geeigneter Fräswerkzeuge und -parameter. In AP-2 wurden erste Legierungsmodifikationen des CoCr-Ausgangswerkstoffes durchgeführt und die Mikrostruktur sowie die Härte analysiert.
T2 - Sitzung des Fachausschusses 01 „Schweißmetallurgie und Werkstoffverhalten“
CY - Online meeting
DA - 17.02.2021
KW - DVS
KW - Legierungsmodifikation
KW - Ultraschallunterstützter Fräsprozess
KW - Additive Fertigung
KW - Fortschrittsbericht
PY - 2021
AN - OPUS4-52179
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
T1 - Monitoring additive manufacturing
N2 - Additive manufacturing (AM) processes allow a high level of freedom in designing and producing components for complex structures. They offer the possibility of a significant reduction of the process chain. However, the large number of process parameters influence the structure and the behavior of AM parts. A thorough understanding of the interdependent mechanisms is necessary for the reliable design and production of safe AM parts.
In this presentation we discuss the online monitoring of metallic AM parts produced by the Laser Powder Bed Fusion (LPBF) process by using optical, thermographic and electromagnetic methods. In a first approach we present the detection of defects generated during the process and discuss how to improve these methods for the optimization of design and production of metallic AM parts.
T2 - Conaendi&IEV 2021
CY - Online meeting
DA - 10.03.2021
KW - Additive Fertigung
PY - 2021
AN - OPUS4-52241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - LIBS In situ Chemical Analysis in Duplex Stainless Steel Welding
N2 - The high corrosion resistance and good mechanical properties of duplex stainless steel (DSS) are due to its special chemical composition, which is a balanced phase ratio of ferrite (α) and austenite (γ). Many industrial applications require the integration of DSS components. For this, tungsten inert gas welding (TIG) is an excellent choice, as it allows an automated operation with high reproducibility. However, when the weld pool solidifies, critical ratios of α- and γ- phases can occur, which leads to solidification cracking, increased susceptibility to corrosion, and a decrease in ductility and critical strength. Previous studies have shown that these defects can be caused by the accumulation of manganese and chromium in the heat affected zone (HAZ), and this accumulation can be detected using LIBS.
Unlike conventional LIBS analyses, which requires reference samples to generate a calibration curve, calibration-free LIBS (CF-LIBS) can determine the chemical composition solely from the emission spectrum of the plasma. Numerous publications show that CF-LIBS is a fast and efficient analytical method for quantitative analysis of metal samples.
We present the results of in situ CF-LIBS analysis during TIG DSS welding. Using a new approach, it is possible to quantitatively determine the chemical composition of the weld metal directly in the welding process. The results of the CF-LIBS analysis are compared with the results of the calibration-based PLS analysis and reasonable agreement is found. Thus, the CF-LIBS method offers the significant advantage of quickly measuring in situ the concentrations of the main alloying elements that prevent the formation of welding defects, without the tedious calibration procedure.
T2 - EMSLIBS 2023
CY - Porto, Portugal
DA - 04.09.2023
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Calibration free
PY - 2023
AN - OPUS4-58314
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
A1 - Engelking, Lorenz
T1 - Bericht zum Fortschritt des laufenden Projekts: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die mit dem Forschungsvorhaben verbundenen Nutzen für KMU sind die Stärkung der Innovationsfähigkeit und der Wirtschaftlichkeit sowie die Erhöhung der Wettbewerbsfähigkeit. In AP-2 wurden die Legierungsmodifikationen des CoCr-Ausgangswerkstoff abgeschlossen und weitere Legierungsmodifikationen des FeNi36-Ausgangswerkstoffes erstellt. In AP-4 wurden erste Zerspanversuche an den Modifikationen des FeNi36-Ausgangswerkstoffes gefahren. Ferner wurden erste Eigenspannungsanalysen an schlichtgefrästen Proben durchgeführt.
T2 - Sitzung des DVS Fachausschusses 01 „Schweißmetallurgie und Werkstoffverhalten“
CY - Online meeting
DA - 22.03.2022
KW - Additive Fertigung
KW - DVS
KW - Fortschrittsbericht
KW - Ultraschallunterstütztes Fräsen
KW - Legierungsmodifikation
KW - Eigensapnnungen
PY - 2022
AN - OPUS4-54911
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Investigations on influencing the microstructure of additively manufactured Co-Cr alloys to improve subsequent machining conditions
N2 - Co-Cr alloys are frequently used for highly stressed components, especially in turbine and plant construction, due to their high resistance to thermal and mechanical stress, as well as to corrosive and abrasive loads. Furthermore, they are classified as difficult-to-cut materials because of their high strength and toughness as well as their low thermal conductivity. However, for Co, an increased cost and supply risk can be observed in recent years. Therefore, additive manufacturing (AM) offers significant economic advantages due to higher material efficiency regarding repair, modification, and manufacturing of such components. Concerning inhomogeneity and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. In addition, subsequent machining, particularly contour milling, is essential to generate the required complex contours and surfaces. Hence, additive and machining manufacturing processes need to be coordinated in a complementary way, especially due to additional challenges arising in milling of heterogeneous hard-to-cut microstructures. Recently, it has been shown that modern, hybrid cutting processes, such as ultrasonic-assisted milling (US), can improve the cutting situation. In this investigation, the Co-Cr initial alloy is additionally modified with Ti and Zr up to 1 wt.-% with the aim to enhance the homogeneity of the microstructure and, thus, the machinability. Hence the investigation includes finish milling tests of the AM components and the comparison of US and conventional machining. Both the modifications and the ultrasonic assistance exhibit a significant effect on the machining situation, e.g., US causes a higher surface integrity of the finish milled surfaces compared to conventional milling.
T2 - International Congress on Welding, Additive Manufacturing and associated non destructive testing
CY - Online meeting
DA - 08.06.2022
KW - Co-Cr-alloy
KW - Additive manufacturing
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
AN - OPUS4-55431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
ED - Hahn, Oliver
ED - Doil, Thorsten
T1 - Workshop Kulturguterhaltung - Vom Dampfkessel zu Nanomaterialien
N2 - Sehr geehrte Damen und Herren,
liebe Leserinnen und Leser,
bereits im ersten Band der N.i.Ke. Schriftenreihe des Netzwerks zur interdisziplinären Kulturerhaltung hatte ich angeführt, dass bei der Untersuchung von kulturellen Artefakten naturwissenschaftliche Untersuchungsmethoden zunehmend an Bedeutung gewinnen, sie eigentlich unverzichtbar geworden sind.
Ein besonders einprägsames Beispiel dieser fächerübergreifenden Zusammenarbeit zwischen Geisteswissenschaften, Naturwissenschaften und Restaurierungswissenschaften war die Ausstellung Johannes Vermeer. Vom Innehalten, die in diesem Jahr in der Gemäldegalerie Alter Meister in den staatlichen Kunstsammlungen Dresden gezeigt wurde. Eigens für diese Ausstellung wurde das Gemälde Brieflesendes Mädchen am offenen Fenster einer grundlegenden Restaurierung unterzogen. Diese Restaurierung diente jedoch nicht nur der Reparatur des Bildes. Um sich dem ursprünglichen Zustand des Gemäldes zwischen 1657 und 1659 anzunähern, wurden später hinzugefügte Malschichten großflächig abgenommen. Möglich wurde dies durch unterschiedliche, bildgebende materialwissenschaftliche Untersuchungen im Vorfeld, welche die wissenschaftlichen Grundlagen für die Diskussion über den weiteren Umgang mit der Lesenden schufen.
Materialanalytische Verfahren wurden und werden ständig weiterentwickelt und optimiert. Sei es, um aus einer Vielzahl von Einzelmessungen ein Gesamtbild zu erstellen, oder die Größe einer Probenentnahme so zu reduzieren, dass von einer „minimal-invasiven“ oder „quasi nicht-invasiven“ Untersuchung ausgegangen werden kann. Nun feiert die Bundesanstalt für Materialforschung und -prüfung, zusammen mit ihren Vorgängerinstitutionen, den königlichen Versuchsanstalten, in diesem Jahr ihren einhundertfünfzigsten Geburtstag. Sie blickt damit auf eine lange Tradition materialwissenschaftlicher Analysen zurück, an deren Beginn beispielsweise die metallographischen Untersuchungen von Adolf Martens stehen. Derartige Untersuchungen bilden auch heute noch einen wesentlichen Bestandteil archäometallurgischer Forschung. Die Historie bzw. die Weiterentwicklung der Methodik lässt sich hier besonders gut nachzeichnen. Jedoch blicken auch Verfahren zur Charakterisierung weiterer Werkstoffe, wie Glas, Keramik, oder organischer Materialien auf eine lange Geschichte zurück.
Die in diesem Band der N.i.Ke.-Schriftenreihe präsentierten Beiträge dokumentieren einerseits aktuelle Forschungsarbeiten, die erst in diesem Jahr in entsprechenden Fachjournalen publiziert wurden, andererseits liegen einige der Arbeiten bereits 50 Jahre zurück. Sie bekunden damit nicht nur die materialtechnologische und historische Bandbreite der Projekte, sondern offenbaren die Vielfältigkeit kulturhistorischer oder restauratorischer Fragestellungen, zu deren Beantwortung natur- und materialwissenschaftliche Forschung wesentliche Beiträge liefern können.
Ich bedanke mich bei allen Kolleginnen und Kollegen, die zur Erstellung dieser dritten Ausgabe der N.i.Ke. Schriftenreihe des Netzwerks zur interdisziplinären Kulturerhaltung beigetragen haben. Ihre Aufsätze ermöglichen den Blick in die Vielfältigkeit materialwissenschaftlicher Untersuchungen im Bereich Kunst- und Kulturgut. Ich wünsche Ihnen viel Spaß auf dieser kleinen Zeitreise.
T2 - Workshop Kulturguterhaltung - Vom Dampfkessel zu Nanomaterialien
CY - Berlin, Germany
DA - 17.11.2021
KW - Pergamonmuseums
KW - Schriftrollen vom Toten Meer
KW - Gold mit Synchrotronstrahlung
KW - Kandelaber des Ensembles am Charlottenburger Tor
KW - Berliner Tuffsteinfassaden
KW - Betondickglasfenster des Glockenturms am Eiermannbau
KW - Kaiser-Wilhelm-Gedächtniskirche
KW - Radiografische Untersuchung
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543239
UR - https://netzwerke.bam.de/Netzwerke/Navigation/DE/Netzwerke/NIKE/nike.html
VL - 3
SP - 1
EP - 155
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54323
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Diana
A1 - Hahn, Oliver
ED - Lois, C.
T1 - Colours on East Asian Maps
N2 - Maps and colours have a close connection. Drawn or printed in black on white, subsequently added colours enhance maps with additional information. Colours were not just there to improve maps aesthetically, but they regulated how they were read and thus reinforced their meanings, significances and ideas. Colour is an important key to a more precise understanding of the map’s purposes and uses; moreover, colours are also an important aspect of a map’s materiality. The material scientific analysis makes it possible to find out more about the making of colours and the process of colouring maps. By skillfully deploying colours, map colourists were able to create mimetic representations of nature or codify information in an abstract form. The use of colours involved many considerations as to the materials. ‘Reading’ colours in this way gives a glimpse into the social lives of mapmakers as well as map users and reveals the complexity of the historical and social context in which maps were produced and how the maps were actually made. Within the scope of the three-year joint research project Coloured Maps (2018–2021), we undertook an in-depth and systematic study of hand-drawn and hand-coloured maps from East Asia in the Museum am Rothenbaum (MARKK) in Hamburg and produced between the seventeenth and twentieth centuries.
With a multi-perspective approach and transdisciplinary methods (humanities and the sciences), we were able to pool and compare the research results from different fields of research on Asian maps. The aim of this publication is to provide a first general overview of the subject of colours on maps in East Asia in the period from the seventeenth to the early twentieth century and to stimulate further research on the topic.
KW - Maps and colours
KW - Colouring
KW - Colourants
KW - Dyes and pigments
KW - Map production and publishing
KW - Non-invasive scientific methods
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569682
UR - https://brill.com/display/title/61839
SN - 978-90-04-54562-5
VL - 2023
SP - 1
EP - 79
PB - Brill
CY - Leiden, Netherlands
AN - OPUS4-56968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Alloy modification for additive manufactured Ni alloy components Part II: Effect on subsequent machining properties
N2 - Alloy 36 (1.3912), also known as “Invar”, is an alloy with 36% nickel. It was developed in 1897 by Guillaume and stands out for its very low thermal expansion coefficient. It is classified as a difficult-to-cut material and is commonly used for the production of fiber-reinforced composites in the field of mold construction. Additive manufacturing (AM) offers many economic advantages regarding the repair, modification and manufacture of entire components. Subsequent machining of the AM components is necessary to account for complex structures, final contours or defined surfaces. This is usually done using a tool with a geometrically defined cutting edge, i.e., milling processes. Surface integrity is determined by metallurgical (e.g., microstructure of the subsurface), topological (e.g., surface defects, roughness) and mechanical (e.g., residual stresses) factors, which is crucial in terms of component safety and performance. Modern, hybrid cutting processes, such as ultrasonic-assisted milling (US), provide potentially improvement of the cutting situation of these components.
In part I of this investigation, the initial alloy 36 is modified with the elements Ti, Zr and Nb up to a maximum of 1 wt.-%. The influence of the modification elements on the microstructure as well as on the hardness of the AM components is examined. Part II focusses on the effect of the alloy modifications on machinability as well as on the surface integrity of plasma-transferred-arc-welded (PTA) and finish milled invar components.
The results show a significant positive influence of ultrasonic assistance on the resulting cutting force of both materials. The modification with 1% Ti shows a positive influence on the surface integrity, as the roughness of the conventional machining processes is lower compared to the initial alloy, which has to be confirmed in further experiments.
T2 - IIW C-II Intermediate meeting
CY - Online meeting
DA - 17.03.2022
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Plasma-Transferred-Arc
KW - Surface integrity
KW - Alloy 36
KW - Additive manufacturing
PY - 2022
AN - OPUS4-54910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Khropost, Diana
A1 - Riethmüller, Franziska
A1 - Döhring, Thorsten
A1 - Flachs, Dennis
A1 - Hülagü, Deniz
A1 - Hertwig, Andreas
A1 - Cotroneo, Vincenzo
A1 - gibertini, eugenio
T1 - Polydopamine – a bio-inspired polymer for X-ray mirror coatings and other technical applications
N2 - Although the organic molecule dopamine (3,4-dihydroxyphenethylamine) is commonly known as one of the “hormones of happiness”, thin polymer films of polydopamine (PDA) also have interesting technical properties. PDA is a very strong glue that sticks on almost everything, even under water. In nature, PDA is found in the byssal thread cuticles of mussels. When produced by dip-coating, the self-organizing PDA layers grow in a reproducible thickness of single or multiple molecule monolayers of a few nanometres thickness only. Here we present an optimized preparation regime as derived from polymerization analysis through absorption spectroscopy. One application is the use of thin PDA overcoatings to increase the soft X-ray reflectivity of astronomical X-ray mirrors. Furthermore, we give an outlook to other technical applications for this interesting material, presenting this bio-inspired organic polymer as an innovative technical solution for the future, with applications such as PDA-based super-capacitors and its promising role in enhancing separator materials for batteries.
T2 - SPIE Optics + Optoelectronics 2025
CY - Prague, Czech Republic
DA - 07.04.2025
KW - X-ray mirrors
KW - Reflectivity
KW - Polydopamine
KW - Ellipsometry
PY - 2025
DO - https://doi.org/10.1117/12.3056298
VL - 13531
SP - 1
EP - 11
PB - SPIE
AN - OPUS4-63630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die additive Fertigung mittels Schweißverfahren bietet große ökonomische Vorteile für eine ressourceneffiziente Bauteilherstellung. Offene Fragen bezüglich Homogenität, Anisotropie der Schweißgefüge und den damit verbundenen Bauteileigenschaften stehen einer wirtschaftlichen Verarbeitung oftmals im Wege. Finale Bauteilgeometrie und Oberflächengüte erfordern meist komplementäre subtraktive Fertigungsschritte. Werkstoffe für hochbelastbare Komponenten sind oftmals schwer spanbar. In einem Vorhaben der BAM und des ISAF wurde untersucht, wie die Modifikation der AM-Schweißzusätze und das ultraschallunterstützte Fräsen (US) die Zerspanungssituation verbessern. Der vorliegende Artikel stellt wesentliche Zusammenhänge zwischen Legierung, Gefüge und Zerspanung zweier schwer spanbarer Hochleistungslegierungen (FeNi und CoCr) dar. Großes Potenzial zeigte neben dem US die Modifikation mit Zr und Hf bei Zulegierung in das Schweißgut mittels Beschichtung von Massivdrähten bzw. Herstellung von Fülldrähten.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium (BMDK)
CY - Magdeburg, Germany
DA - 19.06.2024
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
PY - 2024
AN - OPUS4-60429
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Alloy modification for additive manufactured Ni alloy components Part II: Effect on subsequent machining properties
N2 - Alloy 36 (1.3912), also known as “Invar”, is an alloy with 36% nickel. It was developed in 1897 by Guillaume and stands out for its very low thermal expansion coefficient. It is classified as a difficult-to-cut material and is commonly used for the production of fiber-reinforced composites in the field of mold construction. Additive manufacturing (AM) offers many economic advantages regarding the repair, modification and manufacture of entire components. Subsequent machining of the AM components is necessary to account for complex structures, final contours or defined surfaces. In part I of this investigation, the initial alloy 36 is modified with the elements Ti, Zr and Hf up to a maximum of 0.33 wt.-%. The influence of the modification elements on the microstructure as well as on the hardness of the AM components is examined. Part II focusses on the effect of the alloy modifications on machinability as well as on the surface integrity of plasma-transferred-arc-welded (PTA) and finish milled invar components. Machining tests were carried out, to investigate the influence of ultrasonic assistance and the effects of modification elements Ti, Zr and Hf on the occurring cutting forces, temperatures and resulting surface integrity of the AM components made of alloy 36 and their modifications. The results show a significant positive influence of ultrasonic assistance on the resulting cutting force as well as on the roughness of all materials investigated.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - Alloy modification
KW - Alloy 36
KW - Additive manufacturing
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
AN - OPUS4-55432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Assessment of in-service welding conditions for pressurized hydrogen pipelines via component test
N2 - Hydrogen is the energy carrier of tomorrow. This requires a reliable transport infrastructure with the ability to carry large amounts of hydrogen e.g. for steel industry or chemical industry. The conversion of existing natural gas (NG) grids is an essential part of the worldwide hydrogen strategies, in addition to the construction of new pipelines. In this context, the transportation of hydrogen is fundamental different from NG as hydrogen can be absorbed into the pipeline material. Given the well-known effects of hydrogen embrittlement, the compatibility of the materials for the intended pipelines must be investigated (typically low alloy steels in a wide range of strengths and thicknesses). However, pipelines require frequent maintenance, repair or the need for installation for further outlets. In some cases, it is necessary to perform welding on or onto the pipelines while they are still in service, i.e. with active gas flow under high pressure, e.g. such as the well-known “hot tapping”, see Fig. 1a. This in-service welding causes challenges for hydrogen operations in terms of additional hydrogen absorption during welding and the material compatibility. The challenge can be roughly divided into the possible austenitization of the inner pipe material exposed to hydrogen, which can lead to sufficient hydrogen absorption, and the welding itself, which causes an increased temperature range. Both lead to a significant increase in hydrogen solubility and diffusivity of the respective materials compared to room temperature. In this context, knowledge about hot tapping on hydrogen pipelines is scarce due to the lack of operating experience. Fundamental experimental investigations are required to investigate the transferability from NG to hydrogen pipeline grids. For this reason, the present study introduces a specially designed mock-up / demonstrator concept for the realistic assessment of the welding processing conditions, see Fig. 1b. The mock-up was designed to enable in-situ temperature measurement during welding as well as ex-post extraction of samples for the quantification of the absorbed hydrogen concentration, see Fig. 1c. For safety measures, the necessary pressurized hydrogen volume was limited by the insertion of a solid cylinder ensuring a 1 cm hydrogen gas layer. Welding experiments on the pressurized mock-ups with the diameters DN50 and DN200 have shown that the austenitization temperature can be reached on the inner surface of the pipeline, especially on thinner-walled pipelines, using current welding practices. This corresponds to an increased hydrogen uptake in the welded area of several ppm
T2 - 1st Conference on Hydrogen in Materials Science and Engineering (H2-MSE)
CY - Siegburg, Germany
DA - 11.02.2025
KW - Hydrogen
KW - Pipeline
KW - In-service welding
KW - Component test
PY - 2025
AN - OPUS4-62544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Microalloying influence on precipitation behavior and mechanical properties of welded high strength structural steels
N2 - Microalloying elements, such as Nb and Ti, are essential for the targeted mechanical strength of quenched and tempered, high-strength fine-grained structural steels with a nominal yield strength ≥ 690 MPa. Current specifications for chemical composition only provide upper limits for manufacturers. But even small deviations in the alloying route can have a drastic effect on the mechanical properties. Thus, an adequate prediction of the weldability and the integrity of the welded joint becomes difficult or even impossible due to the varying composition and, hence, the microstructures. Undesirable side effects are the possible softening of the heat-affected zone (HAZ) as well as the opposite effect of hardening. Against this background, different microalloying routes with varying Ti and Nb contents are systematically investigated for the first time on specially designed lab-cast alloys. The basis of each alloy route was the common S690QL in terms of both the chemical composition as well as the heat treatment. To investigate the weldability, three-layer welds were performed using metal active gas welding (MAG) and critical microstructural areas with high softening/hardening were identified. The scope was here on the identification of phase transformations during cooling and on the respective metallurgical precipitation behavior. Isothermal and non-isothermal phase calculations were performed using Thermo-Calc® and showed that the prediction of the non-equilibrium precipitation characteristics during welding is not trivial, especially for this relatively complex chemical composition. The mechanical properties of the welded joints were identified by both Charpy tests (toughness) and tensile tests (strain and strength). During the test, the local straining behavior of the welded joints, was identified using a digital image correlation (DIC) system, see Figure 1. Despite the generally good weldability of the materials, the results show a significant influence of the microalloying route as well as the welding heat input on the different precipitation kinetics.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 04.09.2023
KW - High-strength
KW - Steel
KW - Mechanical properties
KW - Welding
KW - Thoughness
PY - 2023
AN - OPUS4-58221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - In situ investigation of phase distribution and weld solidification in duplex stainless steels using laser-induced breakdown spectroscopy (LIBS)
N2 - Welding processes of duplex stainless steels cause an unbalanced austenite (γ)/ferrite (δ) ratio due to high cooling rates and changes in chemical composition. That causes a degradation of mechanical properties and corrosion resistance. In situ monitoring of the weld pool is to be realized with the help of laser-induced breakdown spectroscopy (LIBS). A major advantage of this technique is the highly accurate time and spatially resolved measurement of the chemical composition during welding. Previous research has established that the LIBS method is suitable to detect chemical elements during welding and to show a distribution of selected elements. Chemical composition in the WM and HAZ can now be quantified using calibration curves generated by certified reference materials (CRM). Furthermore, a cooling rate can be plotted against the measured electron temperature.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - LIBS
KW - In situ measurement
KW - WRC 1992 diagram
KW - duplex stainless steel
KW - TIG welding
PY - 2021
AN - OPUS4-53613
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Khropost, Diana
A1 - Riethmüller, Franziska
A1 - Stanik, Eva
A1 - Döhring, Thorsten
A1 - Hertwig, Andreas
A1 - Hülagü, Deniz
T1 - Polydopamine -a bionic material and its potential applications for batteries
N2 - Polydopamine (PDA) recently came into focus as an innovative material for applications in various technical fields. It is a very strong glue that sticks on almost everything, even under water: In nature, PDA is found in the byssal thread cuticles of mussels. In 2007, Lee et al. first showed that dipping substrates into a solution of dopamine results in the formation of thin PDA films on numerous materials. The simple preparation and the high durability of these coatings have stimulated growing research interest and a wide variety of applications in energy, biomedical and environmental science, and other fields.
We have investigated thin layers of PDA with different methods including ellipsometry, tactile measurements of the layer thickness and in situ absorption measurements during the polymerization process. During polymerization the dopamine solution shows a progressive colour change from transparent to brown that has been monitored by spectrometric measurements. The increasing absorption of the cuvette with dopamine solution can be seen in figure 1. The absorption levels off after approximately 2,5 h of polymerization time, thus indicating termination of the primary formation of the PDA film. This data shows that for homogeneous layer growth it is advantageous to interrupt the process after two hours. To generate a higher layer thickness, the samples need to be cleaned and immersed in a fresh dopamine solution subsequently. In addition, ellipsometry measurements on polydopamine layers could determine the corresponding coating thickness as well as its complex refractive index over a broad wavelength range.
T2 - Materials Week 2025
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - Polydopamine
KW - Ellipsometry
KW - Leyer thickness
PY - 2025
AN - OPUS4-63636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Treutler, K.
A1 - Schröpfer, Dirk
A1 - Wesling, V.
A1 - Kannengießer, Thomas
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungslegierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Im vorliegenden Beitrag werden für die beiden untersuchten FeNi- und CoCr-Legierungen wesentliche Zusammenhänge zwischen verschiedenen Legierungsmodifikationen, der entstehenden Gefügemorphologie und den Zerspanungseigenschaften von mittels PTA additiv gefertigter Proben dargestellt. Hierbei ließen sich Ti, Zr und Hf pulvermetallurgisch zu den jeweiligen Ausgangsschweißzusätzen hinzulegieren.
T2 - #additivefertigung: Metall in bestForm
CY - Essen, Germany
DA - 26.10.2022
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2022
SN - 978-3-96144-202-7
VL - 383
SP - 93
EP - 99
PB - DVS-Media GmbH
AN - OPUS4-56615
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Effect of alloy modification for additive manufactured Ni alloy components on microstructure and subsequent machining properties
N2 - Ni alloys are generally classified as difficult-to-cut materials and cost intensive. Additive manufacturing (AM) offers economic advantages. However, machining of these AM components is mandatory to create the final contour or surface. The inhomogeneous and anisotropic microstructure and properties of AM components causes an unstable cutting process. Moreover, undesirable tensile residual stresses are generated due to subsequent machining. In this investigation, the initial alloy 36 is modified with Ti and Nb up to 1.6 wt.-% and build-up welded via gas metal arc welding (GMAW) and plasma-transferred-arc (PTA). Then, finish-milling tests are carried out to investigate the influence of the modification as well as the cutting parameters on the resulting cutting force and the surface integrity. In addition, the conventional milling process (CM) is compared with the ultrasonic-assisted milling process (US), which has a significant influence on the machinability as well as on the surface integrity.
T2 - Additive Fertigung – Werkstoffe – Prozesse – Wärmebehandlung 2022
CY - Bremen, Germany
DA - 29.06.2022
KW - Additive manufacturing
KW - Alloy 36
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
AN - OPUS4-55429
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Kurzvorstellung des Projektes H2SuD / Wasserstoff und Schweißen Einfluss des Schweißens auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen
N2 - Die Wasserstoffinfrastruktur ist eine zentraler Bestandteil der erfolgreichen Umsetzung der wasserstoffbasierten Energiewende. Dabei bilden Ferngasleitungen quasi das "Rückgrat" der Transportinfrastruktur großer Gasmengen. Dabei müssen unter Umständen Reparaturen an den Pipelines durchgeführt werden. Dabei ist in der Erdgasinfrastruktur das Schweißen an in Betrieb befindlichen (d.h. von Gas durchflossenen) Pipelines Stand der Technik. Es ist jedoch vollkommen offen, inwieweit diese Technik auf die reine Wasserstoffpipelines übertragbar sind. Hierzu leistet das Projekt H2SuD wichtige Beiträge zur Aufklärung des Einfluss eines Reparaturschweißprozesses auf die Wasserstoffaufnahme und Degradation im Betrieb befindlicher H2 Gasleitungen.
T2 - Sitzung des DIN-Gemeinschaftsarbeitsausschusses NA 092 00 05 GA, NAS/NMP: Zerstörende Prüfung von Schweißverbindungen
CY - Berlin, Germany
DA - 15.03.2023
KW - Wasserstoff
KW - Pipeline
KW - Reparatur
KW - Schweißen
PY - 2023
AN - OPUS4-57169
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
A1 - Schröpfer, Dirk
A1 - Börner, Andreas
A1 - Kannengießer, Thomas
A1 - Michels, H.
A1 - Hamm, C.
A1 - Appelt, M.
A1 - Hamacher, M.
T1 - Ultraschallunterstütztes Fräsen zur Reduzierung der Belastung auf Werkzeug und Bauteiloberfläche von Eisenaluminid-Bauteilen
N2 - Intermetallische Werkstoffe werden für Hochtemperaturanwendungen immer wichtiger. Insbesondere Aluminide mit hohen spezifischen Festigkeiten haben ein großes Potenzial für Leichtbauanwendungen, z. B. werden Titanaluminide bereits in Flugzeugturbinen eingesetzt. Ökonomische und ökologische Aspekte sind die treibende Kraft zur Substitution konventioneller Legierungen, z. B. Nickelbasislegierungen, die eine wesentlich höhere Kostenintensität und ein höheres Gewichts-Festigkeits-Verhältnis aufweisen. Insbesondere Eisenaluminide (FeAl) sind aufgrund guter mechanischer Eigenschaften und der guten Verfügbarkeit der wichtigsten Hauptlegierungselemente attraktiv. Speziell entwickelte FeAl-Legierungskonzepte ermöglichen eine wirtschaftliche Produktion im Kokillenguss, bei der die Erstarrung der Schmelze spezielle komplexe Gefüge ermöglicht, um die hohen thermischen und mechanischen Eigenschaften durch eine hohe Anzahl von harten Ausscheidungen entlang der Korngrenzen zu erreichen. Zu diesen Eigenschaften gehört aber auch, dass notwendige Bearbeitungsschritte, wie das Schlichtfräsen, zur Erzielung komplexer Endkonturen, zu vorzeitigem Werkzeugverschleiß und geringen Oberflächengüten führen. Für das finale FeAl-Bauteil ist eine hohe Oberflächenintegrität insbesondere in sicherheitsrelevanten Anwendungen in der Luftfahrt oder im Energiebereich erforderlich. Aus diesem Grund konzentriert sich die vorliegende Untersuchung auf die Mechanismen und die Minimierung des Werkzeugverschleißes und die Auswirkungen auf die Oberfläche eines in Kokille vergossenen FeAl-Bauteils. Neben den Optimierungen des Fräsprozesses und der Werkzeugparameter (Geometrie, Material) wird ein modernes hybrides Bearbeitungsverfahren, das ultra-schallunterstützte Fräsen (USAM), eingesetzt, bei dem eine Überlagerung mit einer hochfrequenten Schwingung des rotierenden Werkzeugs erzeugt wird. Analysen der Kräfte und Temperaturen im Fräsprozess, der Verschleißerscheinungen am Werkzeug und der Oberflächenintegrität zeigen positive Auswirkungen durch USAM. Darüber hinaus wird eine valide Grundlage für die Optimierung des Werkzeugs und des Fräsprozesses geschaffen, um eine hohe Oberflächenintegrität (z. B. Verringerung von Zugeigenspannungen und Defekten) und eine längere Werkzeuglebensdauer zu gewährleisten, die zukünftig eine wirtschaftliche Herstellung von FeAl-Bauteilen ermöglicht.
T2 - 5. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 23.02.2023
KW - Eisenaluminid
KW - Ultraschallunterstütztes Fräsen
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
PY - 2023
VL - 12
SP - 738
EP - 748
PB - Shaker Verlag
CY - Düren
AN - OPUS4-59219
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Influence of various microalloying strategies on the mechanical properties of weld seams in S690QL steel
N2 - Microalloying elements such as niobium (Nb) and titanium (Ti) play a crucial role in achieving the desired mechanical properties of quenched and tempered high-strength fine-grained structural steels with a nominal yield strength of ≥ 690 MPa. Current specifications for the chemical composition only define upper limits for these elements, providing manufacturers with some flexibility. However, even minor deviations in alloying concepts can significantly influence the resulting mechanical properties. Consequently, accurately predicting weldability and the integrity of welded joints becomes challenging or even unfeasible due to variations in composition and the associated microstructural changes. Potential adverse effects include the softening of the heat-affected zone (HAZ) or, conversely, localized hardening phenomena. To address these challenges, various microalloying strategies with different Ti and Nb contents are being systematically investigated for the first time using specially designed laboratory-cast alloys. Each alloying approach is based on the commonly used S690QL steel grade while maintaining consistent chemical composition and heat treatment parameters. To evaluate the weldability, three-layer welds were produced using gas metal arc welding (GMAW), and critical microstructural regions, particularly those within the heat-affected zone (HAZ) exhibiting significant softening or hardening, were identified. The influence of the softened HAZ region on failure behavior was assessed through transverse tensile testing. Digital image correlation (DIC) was employed for in situ analysis of local strain distributions across different HAZ regions. In addition, Charpy tests were carried out on BM, WM and HAZ to determine the Charpy impact toughness. This was supported by metallographic analyses and thermodynamic simulation using ThermoCalc.
T2 - IIW Intermediate Meeting, Com. II-A
CY - Trollhättan, Sweden
DA - 10.03.2025
KW - Welding
KW - Microalloy elements
KW - High strength steels
KW - Mechanical properties
PY - 2025
AN - OPUS4-62691
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Kaltrissprüfung für Offshore-Gründungen
N2 - Die klassische Prüfung der verzögerten, wasserstoffunterstützten Kaltrissbildung von Schweißnähten umfasst mehr als 200 mögliche Prüfverfahren. Von diesen hat aber nur ein kleiner Teil praktische Bedeutung. Unabhängig davon, sind die Prüfverfahren typischerweise auf kleine Bauteilgeometrien beschränkt bzw. hinsichtlich ihrer Anwendungsfähigkeit für große Struktruren oder dickwandige, UP-geschweißte Komponenten wie Monopiles. Als Gründundgsstrukturen für Offshore-Windenergieanlagen können die Monopiles Größen bis zu 9 m Durchmesser, Längen bis zu 100 m, bei Gewichten bis zu 1.300 t erreichen. Hier ist eine Prüfung auf verzögerte Kaltrissbildung schwer durchführbar bzw. muss eine Wartezeit von bis zu 48 h eingehalten werden. Die voliegenende Präsentation gibt einen Überblick über an der BAM entwickelte Demonstratorgeometrien um eine praktikable Kaltrissprüfung auf Laborebene zu ermöglichen. Allerdings unter Beibehaltung der realen Steifigkeits- und Wärmeableitungsbedingungen, wie bei realen Großkomponenten. Zusätzlich wird ein Überblick über die Möglichkeiten von Wasserstoffdiffusionsmessungen zur Ermittlung von Diffusionskoeffizienten gegeben, die wiederum Anwendung in der numerischen Simulation der Wasserstoffdiffusion finden.
T2 - Vortragsreihe des DVS e.V. - Bezirksverband Rostock
CY - Rostock, Germany
DA - 05.12.2024
KW - Schweißen
KW - Rissbildung
KW - Monopile
KW - Kaltriss
KW - Komponententest
PY - 2024
AN - OPUS4-62033
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Fügetechnik in Wasserstofftechnologien: Prozesse und Perspektiven
N2 - Der Vortrag gibt einen tiefen Überblick über die Bedeutung der Füge- und Schweißtechnik in Wasserstofftechnologien. Dazu gliedert sich der Vortrag in die Komplexe H2-Erzeugung, Speicherung, Transport, Anwendung auf und gibt jeweils repräsentative Industriebeispiele für den heutigen Anwendungsstand. Insbesondere werden hier Fertigungstechnologien für Brennstoffzellen vorgestellt, sowie Herausforderungen beim Reparaturschweißen von Wasserstoffpipelines. Zeitgleich wird in einem eigenen Kapitel die Bedeutung der additiven Fertigung ebenso erläutert, wie die aktuellen und umfassenden Tätigkeiten auf dem Gebiet der Normung zu H2-Technologien.
T2 - Vortragsreihe der VDI-Ortsgruppe Magdeburg
CY - Magdeburg, Germany
DA - 23.10.2023
KW - Wasserstofftechnologien
KW - Fügetechnik
KW - Pipelines
KW - Additive Fertigung
KW - Normung
PY - 2023
AN - OPUS4-58671
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Graebner, Maraike
A1 - Giese, Marcel
A1 - Treutler, Kai
A1 - Lorenz, Swenja
A1 - Schröpfer, Dirk
A1 - Wesling, Volker
A1 - Kannengießer, Thomas
T1 - Processing of crack-free Nickel- and Cobalt-based wear protection coatings and defined surfaces by subsequent milling processes
N2 - In the area of plant engineering, steel components are provided with a wear protection coating for efficient use to protect them against corrosive, tribological, thermal and mechanical stresses. The use of innovative ultrasound-assisted milling processes and plasma-welded nickel- and cobalt-based wear protection coatings are being investigated to determine how more favourable machinability can be achieved while retaining the same wear protection potential. The focus is on the NiCrSiFeB alloy, which is intended to replace CoCr alloys in the area of screw machines. The utilization of ultrasonic-assisted milling for the machining of coating materials is a novel approach. The modification of hard facing layers in terms of microstructure and precipitation morphology as well as suitability for machining is investigated and compared with the CoCr alloy. The alloy modifications are generated by a PTA process by systematically adjusting the preheating and interpass temperatures, a crack-free wear-resistant layer can be generated, which is subsequently machined by a milling process. In addition to the crack-free properties, the microstructure, the bonding as well as the mixing between the NiCrSiFeB alloy and a 1.8550 as well as between the CoCr alloy and a 1.4828 are analysed and compared in the joining areas. In addition, heating and cooling rates are determined and a chemical analysis of the weld metals is performed. Furthermore, it was found that the build-up layers of NiCrSiFeB alloy are more difficult to machine using the milling process than the CoCr alloy, as higher milling forces are required.
KW - PTA welding
KW - Wear-resistant alloys
KW - Ultrasonic assisted milling
KW - Wear
KW - Cadding
KW - Milling
KW - Ni-based alloy
KW - Co-based alloy
PY - 2024
DO - https://doi.org/10.1177/14644207241265778
SN - 1464-4207
SP - 1
EP - 17
PB - SAGE Publications
AN - OPUS4-60799
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - Grundlagen Korrosion und Korrosionsschutz
N2 - Im Rahmen des Events des jungen Berufsnetzwerks "die junge gfkorr" der Gesellschaft für Korrosionsschutz e.V. beim Industriepartner Dörken Coatings wurde dieser Vortrag über die Grundlagen der Korrosion und des Korrosionsschutzes gehalten. Themen dieses Vortrags waren unter anderen die Bimetallkorrosion, atmosphärische Korrosion und einige Aspekte des Korrosionsschutzes durch Beschichtungen.
T2 - die junge gfkorr @ Dörken Coatings
CY - Herdecke, Germany
DA - 26.05.2025
KW - Korrosion
KW - Korrosionsschutz
KW - Bimetallkorrosion
PY - 2025
AN - OPUS4-63263
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Statusbericht zum FGS Projekt Gefügeveränderung bei trockener Grobbearbeitung
N2 - Der Vortrag gibt eine Übersicht zum Stand des Projekts zum Thema Gefügeveränderung bei trockener Grobbearbeitung. Es wurden vier verschiedene trockene Oberflächenbearbeitungsverfahren an 2 Werkstoffen eingesetzt um Testoberflächen zu schaffen. Die so gefertigten Oberflächen wurden lichtmikroskopisch untersucht und die jeweiligen Rauhigkeitskennwerte bestimmt. Weiterhin wurden metallografische Querschliffe angefertigt um die verfahrens- bzw. materialabhängigen Einflüsse auf mögliche Gefügeveränderungen zu untersuchen. Zusätzlich wurden elektrochemische Polarisationsversuche durchgeführt um die oberflächenspezifische Korrosionsbeständigkeit der nichtrostenden Stahlproben zu quantifizieren.
T2 - Jahrestagung der Forschungsgemeinschaft Schleifen (FGS) 2023
CY - Würzburg
DA - 21.03.2024
KW - Schleifbearbeitung
KW - Korrosion
KW - Nichtrostender Stahl
KW - Stahl
KW - Verformung
PY - 2024
AN - OPUS4-59739
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Viscous crack healing in soda–lime–magnesium–silicate–ZrO2 glass matrix composites
N2 - AbstractThe present study investigates the influence of the crystal volume content on viscous crack healing in glass ceramic glass sealants. To ensure constant microstructure during healing, soda–lime–magnesium silicate glass matrix composites with varied volume fractions of ZrO2 filler particles were used. Crack healing was studied on radial cracks induced by Vickers indentation, which were stepwise annealed to monitor the healing progress by confocal laser scanning microscopy. Confirming previous studies, healing of radial cracks in pure glass was found delayed by global flow phenomena like crack widening and crack edge and tip rounding to minimize the sample surface. With increasing ZrO2 filler content, these global flow phenomena were progressively inhibited whereas local flow phenomena like sharp crack tip healing could still occur. As a result, crack healing was even accelerated by filler particles up to a maximum filler content of 17 vol% whereas crack healing was fully suppressed only at 33 vol% filler content.
KW - Crack healing
KW - Glass matrix composite
KW - Solid oxide fuell cell
KW - Vickers identation
KW - Viscosity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607860
DO - https://doi.org/10.1111/jace.20002
SN - 0002-7820
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-60786
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gogula, Shravya
A1 - Bornhöft, H.
A1 - Wondraczek, L.
A1 - Sierka, M.
A1 - Diegeler, A.
A1 - Müller, Ralf
A1 - Deubener, J.
T1 - Optical Real-Time Castability Evaluation for High-Throughput Glass Melting
N2 - A novel optical real-time method for evaluating the castability of glass forming melts for laboratory furnaces is presented. The method is based on the analysis of top view images of the melt surface inside the crucible during melting after being subjected to a small mechanical impulse. In this way, the melt surface is excited to oscillate. The difference in contrast between two images taken in quick succession scales with the viscosity, with a larger difference occurring at lower viscosities. The method is designed as an instrument for the in-line evaluation of the castability for a high-throughput glass melting system as part of the joint project “GlasDigital” in the framework of the German Platform Material Digital initiative but is applicable to other laboratory furnaces as well.
KW - Optical Real-Time Castability Check
KW - Image Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618659
DO - https://doi.org/10.52825/glass-europe.v2i.1359
VL - 2
SP - 83
EP - 93
AN - OPUS4-61865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - Bericht aus den DIN Ausschüssen "Korrosion und Korrosionsschutz" und "Korrosionsprüfverfahren"
N2 - Der Vortrag gibt einen Überblick über aktuelle Themen und Normen, die in den DIN Ausschüssen NA 171 "Korrosion und Korrosionsschutz" und NA 177 "Korrosionsprüfverfahren" behandelt werden. Stand des Berichts ist Oktober 2024.
T2 - GfKorr Gemeinschaftssitzung der AKs "Korrosionsuntersuchungen und -überwachung" und "Grundlagen und Simulation"
CY - Online meeting
DA - 13.11.2024
KW - Korrosion
KW - Normung
KW - DIN
KW - Korrosionsschutz
KW - Korrosionsprüfung
PY - 2024
AN - OPUS4-62306
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Bedeutung der Wirksumme bei Nichtrostenden Stählen
N2 - Anhand der Wirksumme ist eine Abschätzung des legierungsabhängigen Einflusses auf den Korrosionswiderstand gegen chloridhaltige Medien möglich. Die berechneten Werte sind nur bei optimaler Wärmebehandlung und Verarbeitung zutreffend.
Die Anwendung einer einfachen Formel unter Berücksichtigung von Chrom, Molybdän und Stickstoff ist in der Regel völlig ausreichend. Das daraus abgeleitete Ranking von Werkstoffen ist für diverse technische Regelwerke und zur Unterstützung der Werkstoffauswahl geeignet.
Für die Warenein-/Ausgangskontrolle ist die alleinige Feststellung der Wirksumme unzureichend. Ergänzende Korrosionsuntersuchungen/-prüfungen zur Beschreibung des Korrosionswiderstandes sind dafür notwendig. Gleiches gilt für die Beurteilung von Schadensfällen. Hier sind Verarbeitung, Einsatzbedingungen und die Konstruktion von ausschlaggebender Bedeutung.
T2 - Fortbildung Kursleiter Kompetenzzentren Edelstahl Rostfrei
CY - Trier, Germany
DA - 25.09.2023
KW - Nichtrostender Stahl
KW - Korrosion
KW - Wirksumme
PY - 2023
AN - OPUS4-58453
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bellon, Carsten
T1 - Artistlib - remote control the radiographic simulator aRTist from Python
N2 - The software aRTist is a simulation tool for the generation of realistic radiographs of virtual radiographic superstructures. With radiographic simulations, virtual component models can be scanned as in a computed-tomography scanner. In modern radiography, simulation has become an important tool to minimize cost- and time-intensive measurements. It is increasingly used to optimize techniques for complex applications, to support the method developments, and for educational purposes. With Artistlib, we have started the development of a programming interface to support use cases where the interactive use of the graphical user interface is not suitable. The open-source Python library is intended to remote control and automate the radiographic simulator aRTist.
T2 - 10th International Symposium on Digital Industrial Radiography and Computed Tomography (DIR 2025)
CY - Paris, France
DA - 01.07.2025
KW - Computed Tomography
KW - Numerical Simulation
PY - 2025
AN - OPUS4-63703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Moschetti, Michael
T1 - Capabilities and Applications of the Robot-Assisted Serial-Sectioning and Imaging (RASI) System
N2 - The Robot-Assisted Serial-sectioning and Imaging (RASI) system at BAM provides automated, high-resolution 3D microstructural characterization for diverse materials. Integrating robotics with precision sectioning, etching, and optical microscopy, RASI reconstructs large volumes (approaching 15 × 15 × 15 mm³) with sub-micron detail. This presentation showcases RASI’s versatility through case studies on cast irons, sintered and additively manufactured steels, and ceramic-metallic packages. We demonstrate how RASI reveals true 3D architectures of features like graphite networks, pores, melt pools, and defects, often missed by 2D analysis. These quantitative datasets elucidate process-microstructure-property relationships and provide crucial 'ground truth' for validating computational models and developing digital twins. Ongoing RASI enhancements will also be highlighted.
T2 - The 7th International Congress on 3D Materials Science (3DMS 2025)
CY - Anaheim, CA, USA
DA - 15.06.2025
KW - 3D microstructural characterization
KW - Deep learning image segmentation
KW - High-throughput materials analysis
KW - Advanced materials’ development
PY - 2025
AN - OPUS4-63693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bellon, Carsten
T1 - Realistische Simulation von Röntgencomputertomografie-Systemen
N2 - Die Entwicklung und Bewertung realitätsnaher Nachbildungen eines industriellen CTSystems in einer Simulationssoftware waren Inhalt des WIPANO Forschungsprojektes CTSimU2 – „Realistische Simulation realer Röntgencomputertomografie-Systeme mit basisqualifizierter Simulationssoftware“. Als Voraussetzung dienen dabei Simulationssoftwares, die durch das Testframework aus dem Vorprojekt CTSimU1 basisqualifiziert wurden. Das Testframework testet die hinreichende physikalische Korrektheit und Funktionalität einer Simulationssoftware (Basisqualifizierung der Software). Für eine realitätsnahe Nachbildung ist nicht nur die Güte der Simulationssoftware, sondern insbesondere die Güte der Parametrisierung des realen CT-Systems in der Simulationssoftware ausschlaggebend. Dabei kann das Vorgehen der Parametrisierung in vier Schritte unterteilt werden: die Datenaufnahme am realen CT-System (Schritt 1), die Auswertung der aufgenommenen Daten für die Generierung allgemeiner Parameterangaben (Schritt 2), die Übertragung der Parameter in die spezifischen Simulationssoftwares (Schritt 3) und die Validierung der resultierenden Simulationsergebnisse Simulationsparameter durch einen geeigneten Test an dimensionellen Messgrößen (Schritt 4) Ziel des Projektes war es neben der Erarbeitung allgemeiner Methoden zur Datenaufnahme und Auswertung der Daten, die Entwicklung eines Tests, auf dessen Basis die ausreichend korrekte Simulation einer realen Anlage im Hinblick auf eine spätere Messunsicherheitsbestimmung beurteilt werden kann. Die erarbeiteten Ergebnisse sollen wie bereits im Vorprojekt CTSimU1 in einen Richtlinienentwurf für die Richtlinienreihe VDI/VDE 2630 übertragen werden. Dieser Beitrag fasst die Arbeiten und Ergebnisse des Projekts zusammen.
T2 - DGZfP Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2024
KW - Computertomografie
KW - Simulation
PY - 2025
AN - OPUS4-63705
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Boccaccini, A. R.
A1 - Müller, Ralf
T1 - Sintering and Crystallization of Fluoride-Containing Bioactive Glass F3
N2 - The fluoride-containing bioactive glass F3 with nominal composition (mol%) 44.8 SiO2 - 2.5 P2O3 - 36.5 CaO - 6.6 Na2O - 6.6 K2O - 3.0 CaF2 is a highly promising candidate for bone replacement applications. Its strong crystallization tendency, however, requires a thorough understanding of the interplay between glass powder particle size, surface crystallization, and sintering. Therefore, this study characterizes the sintering and crystallization of bulk specimens and various particle size fractions by differential thermal-analysis, laser scanning, electron microscopy, X-ray diffraction, and Infrared spectroscopy. Particle size fractions < 56 µm were found to fully densify, while crystals growing from the glass particle surface retard sintering of coarser fractions. Small amounts of a non-stoichiometrically calcium phosphosilicate (Ca14.92(PO4)2.35(SiO4)5.65) occurs as the primary crystal phase followed by combeite (Na4Ca4[Si6O18]) as a temporarily dominating phase. The surface crystallization of both phases was found to be mainly responsible for sinter retardation. During later stages of crystallization, additional phases such as cuspidine (Ca4F2Si2O7) and silicorhenanite (Na2Ca4(PO4)2SiO4) occur, but finally monoclinic wollastonite (CaSiO3) forms as the dominant phase.
KW - Bioactive Glass
KW - Sintering
KW - Crystallization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632482
DO - https://doi.org/10.52825/glass-europe.v3i.2564
SN - 2940-8830
VL - 3
SP - 105
EP - 124
AN - OPUS4-63248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal friction and energy dissipation during fracture in silicate glasses
N2 - To obtain a deeper insight into the nature of energy dissipation during fracture, the internal friction of 13 borosilicate, aluminosilicate, soda-lime, and lead-containing glasses, for which inert crack growth data are known, was measured using dynamic mechanical thermal analysis. For asymmetrically bent glass beams, the loss tangent, tan δ, was determined between 0.2 and 50 Hz at temperatures between 273 K and the glass transition temperature, Tg. It was found that the area under the tan δ vs T·Tg−1 curve correlates with the crack growth exponent, n, in the empirical v = v0·KIn relation between crack growth velocity, v, and stress intensity, KI, which indicates that n correlates with the degree of energy dissipation of sub-Tg relaxation phenomena.
KW - Glass
KW - Internal friction
KW - Crack growth
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631582
DO - https://doi.org/10.1063/5.0255432
SN - 0021-9606
VL - 162
IS - 19
SP - 1
EP - 9
PB - AIP Publishing
AN - OPUS4-63158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pan, Z.
A1 - Waurischk, Tina
A1 - Duval, A.
A1 - Müller, Ralf
A1 - Deubener, J.
A1 - Krishnan, N. M. A.
A1 - Wondraczek, K.
A1 - Wondraczek, L.
T1 - Precise Real‐Time Measurement of Liquid Viscosity Using Digital Video Data
N2 - Quantitative knowledge of liquid viscosity is of fundamental importance in many areas of materials synthesis and processing. However, the determination of viscosity often relies on specialized experimental equipment, offline experimentation, or invasive procedures, in particular when required in extreme conditions such as at high temperature, high pressure, and in confined or corrosive environments. Here, this study proposes and validates a fast and simple method that mimics the intuitive perception of liquid flow within a quantitative framework. For this, this study employs digital video observation to derive quantitative values of the shear viscosity of liquids, with high precision and rapid acquisition rates. The technique involves capturing liquid dynamics after minor mechanical stimulation. Processed imaging data are indexed by similarity and referenced to a digital database generated with a finite element model, from which values of viscosity are obtained in line. The approach is tested on water at room temperature and on a high‐temperature glass melt. Covering a viscosity range of four orders of magnitude, both yield convincing agreement with tabulated reference data at low computational cost.
KW - Image analyses
KW - Liquids
KW - Materials discovery
KW - Similarity analyses
KW - Viscosities
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634606
DO - https://doi.org/10.1002/aisy.202500297
SN - 2640-4567
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-63460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gupta, Kanhaiya
A1 - Poka, Konstantin
A1 - Ulbricht, Alexander
A1 - Waske, Anja
T1 - Identification and authentication of additively manufactured components using their microstructural fingerprint
N2 - In the field of additive manufacturing, the ability to uniquely identify and authenticate parts is crucial for certification, logistics, and anti-counterfeiting efforts. This study introduces a novel methodology that leverages the intrinsic microstructural features of additively manufactured components for their identification, authentication, and traceability. Unlike traditional tagging methods, such as embedding QR codes on the surface or within the volume of parts, this approach requires no alteration to the printing process, as it utilizes naturally occurring microstructural characteristics. The proposed workflow involves the analysis of 3D micro-computed tomography data to identify specific voids that meet predefined identification criteria. This method is demonstrated on a batch of 24 parts manufactured with identical process parameters, proving capable of achieving unambiguous identification and authentication. By establishing a tamper-proof link between the physical part and its digital counterpart, this methodology effectively bridges the physical and digital realms. This not only enhances the traceability of additively manufactured parts but also provides a robust tool for integrating digital materials, parts databases, and product passports with their physical counterparts.
KW - Authentication
KW - Additive manufacturing
KW - X-ray Computed Tomography
KW - Digital fingerprint
KW - Unique identification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630356
DO - https://doi.org/10.1016/j.matdes.2025.113986
SN - 1873-4197
VL - 254
SP - 1
EP - 12
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-63035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Müller, Ralf
A1 - Reinsch, Stefan
A1 - Kiefer, P.
A1 - Deubener, J.
A1 - Balzer, R.
A1 - Behrens, H.
T1 - Crack Growth in Hydrous Soda-Lime Silicate Glass
N2 - Stable crack growth was measured for nominal dry and water-bearing (6 wt%) soda-lime silicate glasses in double cantilever beam geometry and combined with DMA studies on the effects of dissolved water on internal friction and glass transition, respectively. In vacuum, a decreased slope of logarithmic crack growth velocity versus stress intensity factor is evident for the hydrous glass in line with an increase of b-relaxation intensity indicating more energy Dissipation during fracture. Further, inert crack growth in hydrous glass is found to be divided into sections of different slope, which indicates different water related crack propagation mechanism. In ambient air, a largely extended region II is observed for the hydrous glass, which indicates that crack growth is more sensitive to ambient water.
KW - Internal friction
KW - Soda-lime silicate glass
KW - Water content
KW - Stable crack growth
KW - DCB geometry
KW - Stress intensity factor
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506829
DO - https://doi.org/10.3389/fmats.2020.00066
VL - 7
SP - Articel 66
AN - OPUS4-50682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Müller, Thoralf
A1 - Mietz, Jürgen
A1 - Burkert, Andreas
T1 - Investigation of the influence of iron‐containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4
N2 - The corrosion resistance of aluminium surfaces is closely linked to the surfacecstate after a grinding process. For years, iron‐containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary.
For the current investigation, specimens of a technical Al‐Si alloy from the same batch were used. The test specimens were mechanically ground with various resin‐bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron‐containing abrasives on the corrosion behaviour of the Al–Si alloy.
However, the most sensitive measuring method (electrochemical noise)
showed differences in the surface activity depending on the type of abrasive.
KW - Aluminium
KW - Corrosion
KW - Corrosion testing
KW - Grinding
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506762
DO - https://doi.org/10.1002/maco.202011657
SN - 0947-5117
SN - 1521-4176
VL - 71
IS - 10
SP - 1667
EP - 1679
PB - Wiley‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kiefer, P.
A1 - Maiwald, M.
A1 - Deubener, J.
A1 - Balzer, R.
A1 - Behrens, H.
A1 - Waurischk, Tina
A1 - Reinsch, Stefan
A1 - Müller, Ralf
T1 - Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses
N2 - To explore the impact of ambient and structural water on static fatigue, the initiation and growth of 3279 Vickers induced median radial cracks were automatically recorded and analyzed. We find that humidity is more efficient in initiating cracks and promoting their growth than water, which is dissolved in the glass structure. In particular for slow crack growth (< 3x10-6 m s-1), tests in dry nitrogen showed a considerable decrease in the crack growth exponent with increasing water content of the glasses. On the other hand, if tests were performed in humid air, the crack growth exponent was independent of the water content of the hydrous glasses, while stress intensity decreased slightly. These observations indicate that water promotes the processes at the crack-tip regardless of its origin. However, ambient water is more efficient.
KW - Indentation fracture toughness
KW - Slow crack growth
KW - Automated analysis
KW - Hydrous glass
KW - Vickers indentation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513085
DO - https://doi.org/10.3389/fmats.2020.00268
VL - 7
SP - 268
AN - OPUS4-51308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heuser, Lina
A1 - Nofz, Marianne
A1 - Müller, Ralf
T1 - Alkali and alkaline earth zinc and lead borate glasses: Sintering and crystallization
N2 - Glasses in the systems Me2O-ZnO-B2O3 with Me = Li, Na, K, Rb (MeZB), Na2O-ZnO-CuO-B2O3 (NZCuB), CaO-ZnO-B2O3 (CaZB), and Li2O-PbO-B2O3 (LPbB) as a reference, were studied by differential thermal analysis, dilatometry, rotational viscometry, and heating microscopy. A decrease of viscosity and sintering range was found with decreasing number of fourfold coordinated boron. The viscosity of the alkali zinc borate glasses varies only slightly. LPbB and CaZB stand out by their reduced and increased viscosities, respectively. Sodium, potassium, and calcium zinc borate glasses possess a fragility above 76. All glasses were sintered to full density before crystallization. Mostly binary zinc borate phases govern crystallization. A ternary crystalline phase was detected only in the potassium containing sample. The Weinberg glass stability parameter ranges between 0.07 and 0.12. This is caused by the presence of several crystalline phases and varying melting points of even the same crystalline phase in different glass matrices.
KW - Alkali zinc borate glasses
KW - Lead borate glasses
KW - Viscosity
KW - Sintering
KW - Crystallization
KW - Fragility
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556128
DO - https://doi.org/10.1016/j.nocx.2022.100116
SN - 2590-1591
VL - 15
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Sintering and foaming of bioactive glasses
N2 - Sintering, crystallization, and foaming of 44.8SiO2–2.5P2O3–36.5CaO–6.6Na2O–6.6K2O–3.0CaF2 (F3) and 54.6SiO2–1.7P2O3–22.1CaO–6.0Na2O–7.9K2O–7.7MgO (13–93) bioactive glass powders milled in isopropanol and CO2 were studied via heating microscopy, differential thermal analysis, vacuum hot extraction (VHE), Infrared spectroscopy, and time-of-flight secondary ion mass spectrometry. Full densification was reached in any case and followed by significant foaming.
VHE studies show that foaming is driven by carbon gases and carbonates were detected by Infrared spectroscopy to provide the major foaming source. Carbonates could be detected even after heating to 750◦C, which hints on a thermally very stable species or mechanical trapping. Otherwise, dark gray compact colors for milling in isopropanol indicate the presence of residual carbon as well. Its significant contribution to foaming, however, could not be proved and might be
limited by the diffusivity of oxygen needed for carbon oxidation to carbon gas.
KW - Bioactive Glass
KW - Crystallization
KW - Foaming
KW - Sintering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552454
DO - https://doi.org/10.1111/jace.18626
SN - 0002-7820
SP - 1
EP - 11
PB - Wiley online library
AN - OPUS4-55245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deubener, J.
A1 - Behrens, H.
A1 - Müller, Ralf
T1 - An overview on the effect of dissolved water on the viscosity of soda lime silicate melts
N2 - In this review article, the impact of dissolved water on the viscous properties of soda lime silicate melts is addressed against the background of the upcoming switch from natural gas to hydrogen combustion. This change will lead to an increase in the total water content of the glasses by up to 0.4 mol%. In order to better define possible influences of water speciation, water-rich glasses were synthesised under increasing pressure up to the kbar range. It is shown that a distinction must be made between the influence of dissolved OH-groups and H2Omolecules in order to accurately reflect the dependence of isokom temperatures on water content. In addition, an increase of one order of magnitude in the tolerance to higher deformation rates was observed for the range of expected increased water contents during isothermal deformation processes, which is based on the timetemperature superposition principle, i.e. congruent flow curves were determined under isokomal conditions.
KW - Water in glass
KW - Viscosity
KW - Soda lime silicate glass
KW - Shear thinning
KW - Nydrogen melting
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587276
DO - https://doi.org/10.1016/j.nocx.2023.100195
VL - 19
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-58727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes Fernandes, Roger
A1 - Al-Mukadam, Raschid
A1 - Bornhöft, Hansjörg
A1 - Reinsch, Stefan
A1 - Müller, Ralf
A1 - Selle, Susanne
A1 - Deubener, Joachim
T1 - Viscous Sintering of Acid Leached Glass Powders
N2 - The process of viscous flow sintering is a phenomenon that is closely linked to the surface properties of the glass particles. In this work, we studied the extreme case of acid-leaching of soda-lime-silicate glass beads of two different particle size distributions and its effects on non-isothermal viscous sintering of powder compacts. Depth profiling of the chemical composition after leaching revealed a near-surface layer depleted in alkali and alkaline earth ions, associated with concurrent hydration as mass loss was detected by thermogravimetry. Heating microscopy showed that acid treatment of glasses shifted the sinter curves to higher temperatures with increasing leaching time. Modelling of the shrinkage with the cluster model predicted a higher viscosity of the altered surface layer, while analysis of the time scales of mass transport of mobile species (Na+, Ca2+ and H2O) during isochronous sintering revealed that diffusion of Na+ can compensate for concentration gradients before sintering begins. Also, exchanged water species can diffuse out of the altered layer, but the depletion of Ca2+ in the altered surface layer persists during the sinter interval, resulting in a glass with higher viscosity, which causes sintering to slow down.
KW - Glass powder
KW - Viscous sintering
KW - Acid-leaching
KW - Sinter retardation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589008
DO - https://doi.org/10.52825/glass-europe.v1i.681
VL - 1
SP - 37
EP - 53
AN - OPUS4-58900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Viscous healing of Vickers indentation–induced cracks in glass
N2 - AbstractViscous healing of cracks induced by the Vickers indentation in a soda lime magnesium silicate, a soda borosilicate, and a soda aluminosilicate glass (NAS) was studied by laser scanning microscopy. Plots of the crack length, width, and depth normalized to the initial crack length versus time over viscosity merge into single master curves of each of these quantities for each glass. Despite glass properties do not differ strikingly from each other, however, these master curves strongly differ among the glasses. This finding was attributed to a different interplay of various crack healing phenomena. Lateral cracks were found to be responsible for the bulging of the sample surface around the Vickers imprint, which in turn promotes radial crack widening as the main cause of healing delay. The most rapid healing of lateral cracks was observed in NAS in which bulging and crack widening were least pronounced.
KW - Crack healing
KW - Glass
KW - Vickers indentation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587295
DO - https://doi.org/10.1111/jace.19245
SN - 0002-7820
VL - 106
IS - 10
SP - 5795
EP - 5805
PB - Wiley
AN - OPUS4-58729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheffler, Franziska
A1 - Fleck, Mirjam
A1 - Busch, Richard
A1 - Casado, Santiago
A1 - Gnecco, Enrico
A1 - Tielemann, Christopher
A1 - Brauer, Delia S.
A1 - Müller, Ralf
T1 - Surface Crystallization of Barium Fresnoite Glass: Annealing Atmosphere, Crystal Morphology and Orientation
N2 - Controlled oriented crystallization of glass surfaces is desired for high precision applications, since the uppermost crystal layer significantly influences the properties of the material. In contrast to previous studies, the data presented here deal with separated crystals growing at defect-free surfaces in four atmospheres with different degrees of humidity (ambient/dry air, argon and vacuum). A glass with the composition 2 BaO–TiO2–2.75 SiO2 was heat-treated at 825 °C until fresnoite (Ba2TiSi2O8) grew to a significant size. The crystal growth rate is found to increase with increasing humidity. The morphology of the crystals changes from highly distorted dendrites in the driest atmosphere (vacuum) to circular/spear-head-shaped crystals in the wettest atmosphere (ambient air), which we attribute to a decrease in viscosity of the glass surface due to water uptake. The least distorted crystals appear in the form of depressions of up to 6 µm. This has an influence on the observed crystal orientation, as measured by electron backscatter diffraction (EBSD). The pulled-in crystals change the orientation during growth relative to the flat glass surface due to an enrichment in SiO2 at the crystal fronts. This confirms that the orientation of crystals is not fixed following nucleation.
KW - Fresnoite
KW - Surface crystallization
KW - Crystal growth
KW - Crystal morphology
KW - Crystal orientation
KW - EBSD
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587230
DO - https://doi.org/10.3390/cryst13030475
VL - 13
IS - 3
SP - 1
EP - 17
PB - MDPI AG
CY - Basel
AN - OPUS4-58723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Ralf
A1 - Behrens, Harald
A1 - Ageo-Blanco, Boris
A1 - Reinsch, Stefan
A1 - Wirth, Thomas
T1 - Foaming Species and Trapping Mechanisms in Barium Silicate Glass Sealants
N2 - Barium silicate glass powders 4 h milled in CO2 and Ar and sintered in air are studied with microscopy, total carbon analysis, differential thermal Analysis (DTA), vacuum hot extraction mass spectroscopy (VHE-MS), Fourier-transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary-ion mass spectrometry (TOF-SIMS). Intensive foaming of powder compacts is evident, and VHE studies prove that foaming is predominantly caused by carbonaceous species for both milling gases. DTA Shows that the decomposition of BaCO3 particles mix-milled with glass powders occurs at similar temperatures as foaming of compacts. However, no carbonate at the glass surface could be detected by FTIR spectroscopy, XPS, and TOF-SIMS after heating to the temperature of sintering. Instead, CO2 molecules unable to rotate identified by FTIR spectroscopy after milling, probably trapped by mechanical dissolution into the glass bulk. Such a mechanism or microencapsulation in cracks and particle aggregates can explain the contribution of Ar to foaming after intense milling in Ar atmosphere. The amount of CO2 molecules and Ar, however, cannot fully explain the extent of foaming. Carbonates mechanically dissolved beneath the surface or encapsulated in cracks and micropores of particle aggregates are therefore probably the major foaming source.
KW - Milling
KW - Foaming
KW - Glass powder
KW - Sintering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531227
DO - https://doi.org/10.1002/adem.202100445
SN - 1438-1656
VL - 24
IS - 6
SP - 2100445-1
EP - 2100445-13
AN - OPUS4-53122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rabin, Ira
T1 - Black writing inks: From Antiquity to the Middle Ages
N2 - Tracing the transition from writing inks based on soot, common in Antiquity to the iron-gall inks commonly used in the Middle Ages builds a focus of our investigative work at the BAM and the Centre for the Studies of Manuscript Cultures (CSMC) [1-4]. With the aim of creating a detailed history of writing black inks, we worked out a non-invasive protocol to collect statistically relevant ink data from dated and localized manuscripts covering a large time span and different geographic areas.
The first step of our protocol consists of the screening carried out by means of the NIR & IRR reflectography. The optical differences between carbon, tannin, and iron-gall inks are best recognized by comparing their response to the infrared light: carbon ink has a deep black color, iron-gall ink becomes transparent above 1400 nm, and tannin ink disappears at about 750 nm, we have simplified the analysis using a small USB microscope with built-in NIR (940 nm) and UV (395 nm) LED in addition to an external white light source [1]. Comparing the images under white and near infrared illumination, we determine the ink typology by observing the changes in the opacity of the ink. Here, carbon-based inks show no change in their opacity when illuminated with NIR wavelength, while the opacity of iron-gall inks changes considerably, and tannin inks become transparent. Our own recent finding that mixed carbon / iron-gall inks were quite popular in the late Antiquity and early Middle Ages suggested to return to the conventional IRR method.
The presentation will show the panorama of historic inks and our attempt to follow up the transition of the inks from those based on soot to the iron-gall inks commonly used in the Middle Ages.
T2 - Seminar University of Oslo
CY - Oslo, Norway
DA - 23.09.2022
KW - Ink
KW - Historic ink
PY - 2022
AN - OPUS4-61194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Microstructure and local mechanical properties of friction stir welded dissimilar joints of CoCrFeMnNi and CoCrNi to austenitic steel AISI 304
N2 - Multiple principal element alloys (MPEA) represent a meanwhile widely investigated material class, which encompass high-entropy (HEA) and medium-entropy alloys (MEA). They are fundamentally different from conventional materials like Fe-Cr-Ni-based austenitic steels. However, the focus has been merely on the material synthesis. With the increase in available material quantities, the focus is now shifting to processing issues such as joining and welding. In this context, the weldability of MPEAs has received very little attention so far. In addition, MPEA/HEA/MEA are and will be expensive due to the alloying concept. From this point of view, also such materials will also have to be joined with other conventional materials like austenitic steels. In particular, there is a lack of experience with dissimilar metal welds (DMWs) and the corresponding mechanical properties. For this reason, the present study summarizes comprehensive experimental results on equiatomic CoCrFeMnNi (HEA) and CoCrNi (MEA), joined by solid-state friction stir welding (FSW) to an austenitic steel AISI 304. The mechanical properties were obtained by cross-weld tensile tests. For the first time (for these welding process and materials), the local strains in the different weld microstructures were measured in-situ by digital image correlation (DIC). A significant influence of the FSW process on both the resulting microstructure and the mechanical performance of the DWMs was identified. For example, the dynamic recrystallization plays a significant role in the performance of the welded joint. In addition, the FSW experiments proofed the weldability of both MPEAs when joined to austenitic steel AISI 304. This allows for further focused consideration of these highly innovative MPEAs.
T2 - MSE 2024: International Materials Science and Engineering Congress
CY - Darmstadt, Germany
DA - 24.09.2024
KW - High-entropy alloy
KW - Dissimilar metal weld
KW - Microstructure characterization
KW - Mechanical properties
KW - Friction stir welding
PY - 2024
AN - OPUS4-61157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Update on "Call for interested people to contribute to series of comprehensive papers on welding and joining of components for sustainable energy systems"
N2 - Based on the initial call in March 2024, an update time-frame is introduced on the working plan for a comprehensive review paper series on joining and welding technologies for the manufacturing of components and parts used in sustainable energy generation, conversion, and transport with focus on hydrogen and wind energy.
T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission II-A
CY - Ixia, Rhodes, Greece
DA - 07.07.2024
KW - Review paper
KW - Research study
KW - Hydrogen
KW - Joining
KW - Welding
PY - 2024
AN - OPUS4-60674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Challenges and difficulties in repair welding procedures on in-service hydrogen pipelines
N2 - Hydrogen as an energy carrier plays a key role in tomorrow's energy transition. For effective use of hydro-gen as energy carrier the construction of the corresponding infrastructure is of utmost importance. In that context, large diameter long-distance transmission pipelines will form the so-called hydrogen backbone in the European Union with service pressures up to 100 bar (e.g., depending on national regulations). From an economically and ecologically point of view, a major goal is to repurpose the existing natural gas (NG) infra-structure to minimize the need to install new pipelines. To ensure the safety, reliability and integrity of this future hydrogen infrastructure repair welding or further welding of branch pipes etc. can be necessary at in-service conditions, meaning a permanent flow of pressurized hydrogen while executing the repair procedure. The reason is that a shut-down of large diameter pipelines is not easy or sometimes merely impossible. In fact, as long, as no oxygen enters the pipeline, there will neither be any combustion nor (in the worst-case scenario) explosion. The special techniques like hot tapping or stoppling are state-of-the-art for NG and oil pipeline grids. Currently, it is not finally clarified if repair welding procedures for NG pipelines can be trans-ferred to pure hydrogen pipelines. In opposite to NG, hydrogen can be way easier absorbed to the pipeline steels and diffuses through the material. If it accumulates in susceptible regions, i.e., in the welded joint or heat affected zone, hydrogen assisted embrittlement could occur and lead to loss of integrity or even cata-strophic failure of the pipeline. For example, requires the planned welding procedure a preheating and maintenance of the weld joint of up to 300°C for up to several hours at the outer. This temperature is way higher compared to the typical service temperature of max. 60°C at operational pressures of up to 100 bar. In accordance to API 941, these low-alloyed pipeline steels are subjected to short-term service loads, which they are not designed for. Another considerable fact is that if the weld seam is attached to the pipeline, the temperature especially for small wall thickness can be easily above the austenitization temperature. It is well known that austenite has a way higher hydrogen solubility compared e.g. to ferrite/bainite microstructure of the low-alloyed steel. Current studies indicate a remarkable increase of the hydrogen ingress dur-ing the austenitization from the inner pipe wall. It must be answered if a critical material degradation because of increased hydrogen uptake due to in-service welding procedures is likely to occur.
T2 - MPA Seminar 2024
CY - Stuttgart, Germany
DA - 08.10.2024
KW - In-service
KW - Pipeline
KW - Hydrogen
KW - Welding
KW - Repair
PY - 2024
AN - OPUS4-61468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Component test for simplified testing of hydrogen‐assisted delayed cold cracking of high‐strength, submerged arc‐welded offshore steel structures
N2 - Offshore Wind Turbines (OWT) are a key factor in tomorrow's sustainable energy generation. The ever-increasing installation depth and weight of OWTs require suitable foundation concepts such as monopiles or tripods. Typically, mild steels such as S420ML are used with plate thicknesses of up to several hundred mm, resulting in high restraints in the welded joints. The large plate thickness requires high-efficiency welding processes such as submerged arc welding (SAW) with multiple wires. Due to the very high stiffness and plate thickness of the large-scale offshore structure, a susceptibility to time-delayed hydrogen assisted cracking (HAC) may occur. The evaluation of this crack susceptibility is very complex due to the component size and stiffness of real offshore structures. For this purpose, a near-component test geometry was developed to transfer the real stiffness conditions to laboratory (i.e. workshop) scale. The 350 kg mock-up studied consisted of heavy plates (thickness 50 mm, seam length 1,000 m) joined by a 22-pass submerged-arc weld. Additional stiffeners simulated the effect of high restraint or shrinkage restraint of the weld. Extreme scenarios of hydrogen absorption during welding were simulated by using flux in dry (HD < 5 ml/100g Fe) and wet (HD > 15 ml/100g Fe) conditions. Weld residual stresses were determined using a robotic X-ray diffractometer. Areas of critical tensile residual stress (at the level of the yield strength) were found in the weld metal and in the heat affected zone, suggesting that these weld sub-zones are the most critical in the case of hydrogen ingress. To identify possible delayed cracking, the welds were tested by phased array ultrasonic testing (PAUT) after welding, 6 h, 12 h, 24 h, and a maximum of 48 h. Summarized, no significant occurrence of HAC was detected, indicating the high crack resistance of the welded joint, i.e., a suitable combination of base material, welding consumable and parameters.
T2 - MPA Seminar 2024 - Materials, Processes, Applications
CY - Stuttgart, Germany
DA - 08.10.2024
KW - Hydrogen
KW - Offshore wind turbine
KW - Component test
KW - Submerged arc welding
KW - Minimum waiting time
PY - 2024
AN - OPUS4-61323
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
T1 - Repair welding of in-service hydrogen pipelines - concepts and challenges
N2 - Hydrogen is set as the energy carrier of tomorrow for a more sustainable fossil fuel free future. As this necessitates a reliable transport infrastructure, repurposing of the existing natural gas grid is planned. With regards to the well-known effect of hydrogen embrittlement, the compatibility of utilized materials must be investigated. First comprehensive studies on pipeline material hydrogen compatibility indicate that these materials can be applied to a certain extent. Nonetheless, the material compatibility is currently of high interest and focus of numerous research projects worldwide. However, pipelines require frequent maintenance and repair work. As part of these, in some cases it is necessary to do weldments onto pipelines while they are pressurized. This in-service welding introduces additional challenges for the material compatibility. Due to the resulting high temperatures, the metallurgical changes in the material and of course the presence of high-pressure hydrogen in the pipeline, additional investigations need to be conducted to ensure that no critical material degradation because of increased hydrogen absorption occurs and an overall material compatibility is given. For this reason, the present paper introduces in-service welding on pipelines. An overview of current research projects that deal with the application of in-service welding specifically on hydrogen pipelines and the emerging problems when applying these techniques on hydrogen pipelines is given. Methods of material testing, their limits and possible solutions are presented and discussed.
T2 - 15th International Pipeline Conference and Exhibition (IPCE 2024)
CY - Calgary, Alberta, Canada
DA - 23.09.2024
KW - Hydrogen
KW - In-Service
KW - Pipelines
KW - Repair welding
PY - 2024
AN - OPUS4-61471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
A1 - Engelking, Lorenz
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, Ronny
A1 - Hälsig, Andre
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Fertigungsbedingte Beanspruchungen und Kaltrisssicherheit in generativ gefertigten Bauteilen aus hochfesten Feinkornbaustählen
N2 - Additive Fertigungsverfahren wie das Direct Energy Deposition-Arc (DED-Arc) oder Wire Arc Additive Manufacturing (WAAM) ermöglichen die effiziente Herstellung gewichtsoptimierter, endkonturnaher Bauteile im modernen Stahlbau. Steigerungen der Effizienz können durch den Einsatz hochfester Stähle erreicht werden, insbesondere durch Verringerung von Wandstärken und Bauteilgewicht sowie signifikante Einsparung
von Kosten, Zeit und Ressourcen. DED-Arc Schweißzusatzwerkstoffe sind bereits auf dem Markt verfügbar, allerdings fehlen Richtlinien und quantitative Kenntnisse über die schweißbedingte Beanspruchung während der Fertigung und im Betrieb, welche den industriellen Einsatz stark limitieren. In einem gemeinsamen Projekt der BAM und der Technischen Universität Chemnitz wurden die wesentlichen Einflüsse und komplexen Wechselwirkungen von Werkstoff, Fertigungsverfahren, Konstruktion und Bearbeitungsschritten auf die Eigenspannungen untersucht. Ziel war es, den stahlverarbeitenden Anwendern, insbesondere KMU, eine risssichere und beanspruchungsgerechte Herstellung und Modifizierung von Bauteilen und Halbzeugen aus hochfesten Feinkornbaustahl unter Verwendung MSG-basierter generativer Verfahren zu ermöglichen.
T2 - DVS Innovationstage 2024
CY - Düsseldorf, Germany
DA - 10.04.2024
KW - Wire Arc Additive Manufacturing (WAAM)
KW - Feinkornbaustähle
KW - Additive Fertigung
KW - Kaltrisssicherheit
KW - Direct Energy Deposition-Arc (DED-Arc)
PY - 2024
SP - 96
EP - 104
AN - OPUS4-61932
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Bericht zum Fortschritt des laufenden Projekts: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die mit dem Forschungsvorhaben verbundenen Nutzen für KMU sind die Stärkung der Innovationsfähigkeit und der Wirtschaftlichkeit sowie die Erhöhung der Wettbewerbsfähigkeit. In AP-1 wurden Zerspanversuche am FeNi- und CoCr-Ausgangswerkstoff durchgeführt. Ziel der Versuche war in erster Linie die Identifikation geeigneter Fräswerkzeuge und -parameter. In AP-2 wurden die Legierungsmodifikationen des CoCr-Ausgangswerkstoffes durchgeführt und die Mikrostruktur sowie die Härte analysiert. In AP-4 wurden erste Zerspanversuche in Abhängigkeit der Legierungsmodifikation der CoCr-Legierung durchgeführt.
T2 - Sitzung des Fachausschusses 01 „Schweißmetallurgie und Werkstoffverhalten“ des DVS
CY - Online meeting
DA - 26.10.2021
KW - Fortschrittsbericht
KW - DVS
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2021
AN - OPUS4-53636
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Adequate repair concepts for high-strength steel weld joints considering design influences
N2 - The sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of design and welding-induced residual stress can lead to crack formation and ultimately to component failure, particularly in interaction with the degradation of the microstructure and mechanical properties high-strength steels during the repair process.
In this context, component-related investigations (FOSTA-P1311/IGF-Nr. 20162 N) focusing on welding residual stress evolution during local thermal gouging and rewelding of S500MLO and S960QL are carried out using in-situ digital image correlation (DIC) and ex-situ X-ray diffraction methods (XRD). Therefore, self-restrained specimens were systematically gouged and rewelded with defined welding heat control (heat input, working temperature) and parameters. By means of structural mechanics calculations, geometries of self-restrained specimens were identified, that represent defined rigidity conditions of repair welds of real components. It could be shown that with increasing restraint intensity significantly higher residual stresses occur in the weld metal and heat affected zone. Furthermore, it revealed that the transverse stresses along the weld seam decrease at the weld seam ends leading to different stress state during gouging and welding. XRD analysis of the local residual stresses after cooling to RT longitudinal and transverse to the weld direction showed a good comparability with global DIC analyses.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium der Otto-von-Guericke Universität Magdeburg
CY - Magdeburg, Germany
DA - 20.10.2021
KW - High-strength steels
KW - Repair welding
KW - X-ray diffraction
KW - Digital image correlation
PY - 2021
AN - OPUS4-53640
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Treutler, K.
T1 - Nickel-iron-alloy modification to enhance additively welded microstructure for subsequent milling
N2 - The aerospace industry uses nickel-iron-alloys to create moulding tools for composite materials because of the low coefficient of thermal expansion. These tools have a large-sized and complex structure, making them cost-intensive and difficult to manufacture. Therefore, the focus is set on additive manufacturing, which can additionally enable the repair of components in order to eliminate local defects. However, the process usually results in a heterogeneous microstructure and anisotropic mechanical properties. As there is a high demand for a precise and exact fit of the precision moulds and thus the surface quality, the welded components must be subsequently machined. Nickel-iron alloys are difficult to machine and an inhomogeneous microstructure also leads to unstable cutting forces.
Consequently, a refinement and homogenisation of the microstructure morphology is achieved through specific alloy modifications in order to stabilise and improve the subsequent machining process. Studies on the refinement of FeNi 36 based on vacuum arc melting furnaces are used as a starting point. Therefore, titanium and niobium are chosen as modification elements with a maximum 1 % weight percent and are added to nickel-iron base alloy. The elements are alloyed and build-up welded by using plasma-transferred-arc welding. The resulting microstructure morphology of the welded wall structure and the machining properties are then determined. Furthermore, the influence on the coefficient of thermal expansion is investigated in connection with the modification and the welding process itself. It can be shown that even small amounts of niobium have a significant influence on the structural morphology of the welded layers during plasma-transferred-arc welding.
T2 - 2nd international Conference on Advanced Joining Processes 2021
CY - Sintra, Portugal
DA - 21.10.2021
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Nickel-iron-alloy
KW - Additive manufacturing
KW - Plasma transferred arc welding
PY - 2021
AN - OPUS4-53635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Bericht zum Fortschritt des Projektes "Entwicklung von Wärmenachbehandlungskonzepten zur Vermeidung von Spannungsrelaxationsrissen" zur Sitzung des FA1
N2 - Dieses Dokument fasst den Projekfortschritt des BAM-Projektes "Entwicklung von Wärmenachbehandlungsstrategien zur Vermeidung von Spannungsrelaxationsrissen" im Rahmen des Fachausschusses 1 "Schweißmetallurgie" des DVS e.V.
T2 - Sitzung des FA1 "Schweißmetallurgie" der Forschungsvereinigung Schweißen und verwandte Verfahren des DVS e.V.
CY - Online meeting
DA - 26.10.2021
KW - Spannungsrelaxationsrisse
KW - Forschung
KW - Schweißen
KW - Wärmenachbehandlung
PY - 2021
AN - OPUS4-53647
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Regelwerke aus Forschungsvorhaben der Forschungsvereinigung des DVS: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungsle¬gierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Es werden die Ergebnisse der Mikrostruktur und der Zerspanbarkeit der Modifikationen der FeNi36-Referenzlegierung mit 0,33 Gew.-% Ti, Zr sowie Hf und der Modifikationen der CoCr-Referenzlegierung mit 1 Gew.-% Ti, Zr sowie Hf vorgestellt. Abschließend werden aus den Ergebnissen Handlungsempfehlungen abgeleitet.
T2 - Sitzung der Arbeitsgruppe (AG) V 12 „Additive Fertigung“
CY - Online meeting
DA - 23.11.2022
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2022
AN - OPUS4-56610
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Bericht zum Fortschritt des laufenden Projekts: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die mit dem Forschungsvorhaben verbundenen Nutzen für KMU sind die Stärkung der Innovationsfähigkeit und der Wirtschaftlichkeit sowie die Erhöhung der Wettbewerbsfähigkeit. In AP-2 wurden die Legierungsmodifikationen des CoCr-Ausgangswerkstoffes sowie des FeNi36-Ausgangswerkstoffes abgeschlossen. In AP-4 wurden Zerspanversuche an den Modifikationen des FeNi36-Ausgangswerkstoffes sowie des CoCr-Ausgangswerkstoffes gefahren. Ferner wurden die zur Übertragung auf den MSG-Prozess ausgewählten Modifikationen beider Ausgangswerkstoffe vorgestellt.
T2 - Sitzung des Fachausschusses 01 „Schweißmetallurgie und Werkstoffverhalten“ des DVS
CY - Magdeburg, Germany
DA - 09.11.2022
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2022
AN - OPUS4-56609
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eissel, A.
T1 - Bericht zum Fortschritt des laufenden Projekts:„Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - In vielen Anwendungen werden aufgrund zunehmender Anforderungen an den Widerstand gegenüber hohen, kombinierten mechanischen, tribologischen, thermischen und korrosiven Beanspruchungen Hochleistungsle¬gierungen eingesetzt. Den vielfach komplexen Bauteilstrukturen, herausfordernden Fertigungseigenschaften und der Erhöhung der Ressourceneffizienz lässt sich heute mit der additiven Fertigung (AM) begegnen, dem oftmals noch unzureichende Kenntnisse über die resultierende Homogenität und Anisotropie der speziellen Gefüge und den damit verbundenen Eigenschaften entgegensteht. Viele Anwendungen benötigen zudem definierte Oberflächen mit hohen Anforderungen an die Oberflächenintegrität, dem durch komplementären Einsatz von additiven und abtragenden Fertigungsschritten Rechnung getragen wird. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind infolge der niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit äußerst herausfordernd mit Blick auf eine wirtschaftliche Zerspanung mit geometrisch bestimmter Schneide. Ein Vorhaben (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF befasst sich mit der Lösung dieser Problemstellung durch gezielte Beeinflussung des Gefüges mittels Modifikation der Schweißzusatzwerkstoffe und den Einsatz des ultraschallunterstützten Fräsens (US), bei gleichzeitiger Sicherstellung der geforderten Eigenschaften der untersuchten Werkstoffe. Im vorliegenden Beitrag werden für die beiden untersuchten FeNi und CoCr-Legierungen wesentliche Zusammenhänge zwischen ver¬schiedenen Legierungsmodifikationen, der entstehenden Gefüge¬morphologie und den Zerspanungseigenschaften von mittels PTA additiv gefertigter Proben dargestellt. Hierbei ließen sich Ti, Zr und Hf pulvermetallurgisch zu den jeweiligen Ausgangsschweißzusätzen hinzulegieren.
T2 - #additivefertigung: Metall in bestForm
CY - Essen, Germany
DA - 26.10.2022
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
PY - 2022
AN - OPUS4-56613
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Untersuchungen zum Einfluss der Amplitude beim ultraschallunterstützten Schlichtfräsen schwer spanbarer FeNi Legierungen
N2 - Es werden erzielte Ergebnisse des ultraschallunterstützen Schlichtfräsens einer schwer spanbaren FeNi-Legierung vorgestellt. Dabei wird der Einfluss der Amplitude der Ultraschallunterstützung auf die Zerspankraft sowie die Oberflächenintegrität untersucht, wobei ein besonderer Fokus auf die Passivkraft gelegt wird. Die Ultraschallunterstützung bedingt beim Schlichtfräsen der Alloy 36 im Vergleich zum konventionellen Fräsprozess eine signifikante Reduzierung der resultierenden Zerspankraft sowie der Rauheit. Außerdem werden oberflächennahen Druckeigenspannungen induziert. Eine Angehobene Osziallations-Amplitude beim ultraschallunterstützten Fräsen bewirkt eine Erhöhung des Anteils der Passivkraft an der resultierenden Zerspankraft sowie eine Erhöhung der oberflächennahen Druckeigenspannungen und eine Verringerung von Oberflächendefekten und Rauheitskennwerten.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Magdeburg, Germany
DA - 30.11.2022
KW - Ultraschallunterstütztes Fräsen
KW - Alloy 36
KW - Oberflächenintegrität
PY - 2022
AN - OPUS4-56612
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Fügetechnik für die neue Wasserstoffökonomie – Werkstoffe, Schweißtechnologien, Perspektiven –
N2 - Die Studie gibt einen Überblick über die Aspekte der Fügetechnik und ihrer Bedeutung in Wasserstofftechnologien. Dazu werden die Grundlagen der Technologiefelder Wasserstofferzeugung, -speicherung, -transport und -nutzung vorgestellt und der Stand der Technik der fügetechnischen Fertigung von Komponenten in Wasserstofftechnologien zusammengefasst. Dabei werden nicht nur exklusiv Metalle betrachtet. Anhand repräsentativer Beispiele aus der Praxis, Forschung und Entwicklung wird die Bedeutung der Fügetechnik in Wasserstofftechnologien klar herausgestellt und mögliche Perspektiven für die Zukunft abgeleitet. Hier ist ersichtlich, dass Fügetechnologien wesentliche Bedeutung für die erfolgreiche Umsetzung von technischen Komponenten der Wasserstofftechnologien haben, von der Erzeugung bis zur Anwendung. Aus gesamtwirtschaftlicher Sicht umfassen die Schwerpunkte bzw. Trends der Fügetechnik dabei: die Erstellung neuer Infrastruktur für Wasserstoffspeicherung und -transport sowie die sichere Umnutzung der bestehenden Erdgasinfrastruktur. Bei der Wasserstoffanwendung wird die effiziente massentaugliche Produktion von Brennstoffzellen immer wichtiger. Es ist zudem klar ersichtlich, dass die additive Fertigung bereits jetzt ein hohes Potential für Komponenten von Wasserstofftechnologien besitzen und dieses wachsen wird. Aus den perspektivischen Anwendungen ergeben sich zudem Herausforderungen und Forschungsbedarfe für die notwendigen nationalen und internationalen Regelwerke und technischen Normen. Schwerpunktmäßig sind hierbei die bereits bestehenden Empfehlungen und kodifizierten Regeln vollständig zu adaptieren und in die Aus- und Weiterbildung von fügetechnischem Fachpersonal einzubetten.
KW - Fügetechnik
KW - Wasserstoff
KW - Werkstoffe
KW - Prozesse
KW - Perspektiven
PY - 2021
UR - https://www.dvs-media.eu/de/neuerscheinungen/4425/dvs-studie-zur-fuegetechnik-fuer-die-neue-wasserstoffoekonomie-werkstoffe-schweisstechnologien-perspektiven
SN - 978-3-96144-157-0
SN - 978-3-96144-158-7
VL - 373
SP - 1
EP - 59
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-53498
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Beanspruchungsgerechte Reparatur beim Bauteilschweißen hochfester Feinkornbaustähle
N2 - Eine nachhaltige und ressourceneffiziente Fertigung und Errichtung von Windenergieanlagen, sowohl auf See als auch an Land, erfordert zunehmend den Einsatz moderner hochfester Feinkornbaustähle. Werden nach dem Schweißen dieser hochfesten Konstruktionen unzulässige Defekte detektiert, sind nach geltenden Verarbeitungsrichtlinien die defekten Bereiche durch lokales Ausfugen und anschließendes Schweißen zu reparieren. Fehlende Informationen zu adäquaten Reparaturkonzepten in den Regelwerken bedingen oftmals eine unzureichende Berücksichtigung dabei auftretender zusätzlicher Beanspruchungen durch die erhöhte Schrumpfbehinderung der Ausfugenuten. Zusätzlich haben die ausführenden Betriebe vielfach kaum Kenntnis über die Degradation angrenzender Gefüge durch thermische Ausfugeprozesse und erneutes Schweißen, die in diesem Zusammenhang besonders bei den hochfesten Stählen als kritisch anzusehen sind. Das aktuelle Forschungsvorhaben der BAM (FOSTA P1311/IGF-Nr.20162N) fokussiert hierfür systematisch bauteilrelevante Untersuchungen zu den schweißbedingten Beanspruchungen und Gefügeveränderungen bei der Reparatur von hochfesten Schweißverbindungen. Wesentlich sind hierbei der Einfluss der Schrumpfbehinderung, der Wärmeführung beim Schweißen und Ausfugen sowie der Reparaturzyklenanzahl und die metallurgischen Aspekte bei den hochfesten Güten S500MLO für zukünftige Offshore-Anwendungen und S960QL für aktuelle Mobilkrananwendungen. Aufbauend auf einigen Studien zur schweißbedingten Beanspruchung hochfester Stähle zeigt der vorliegende Beitrag die Identifikation geeigneter Probengeometrien und Schweißdetails mittels numerischer und experimenteller Analysen. Dadurch wird die Übertragbarkeit der vorgestellten Schweißexperimente und Ergebnisse hinsichtlich der resultierenden Schweißeigenspannungen auf reale Reparaturfälle im Bereich des hochfesten Stahlbaus sichergestellt. Es zeigt sich in Übereinstimmung mit früheren Ergebnissen eine signifikante Erhöhung der Beanspruchungen an den variierten schlitzförmigen Prüfnähten. Das Eigenspannungsniveau sowohl im Schweißgut als auch in der WEZ korreliert mit dem Einspanngrad. Mit dem Ziel beanspruchungs- und werkstoffgerechte Reparaturkonzepte zu erarbeiten, sind zum einen geringere Wärmeinbringungen, besonders durch niedrige Zwischenlagentemperaturen und Einspannbedingungen anzustreben, um hohe Beanspruchungen und kritische Gefügedegradationen im Reparaturbereich zu vermeiden. Dies wird durch systematische Untersuchungen zum Ausfugen und Schweißen sowie letztlich dem Transfer von Verarbeitungsempfehlungen für die Anwender und Richtlinien erreicht.
T2 - DVS Congress 2021
CY - Essen, Germany
DA - 14.09.2021
KW - Eigenspannungen
KW - Hochfest
KW - Feinkornbaustahl
KW - Reparatur
KW - Schweißen
PY - 2021
AN - OPUS4-53317
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Consideration of design influences to provide adequate repair concepts for high-strength steel weld joints in offshore support structures
N2 - The sustainable and resource-efficient production of offshore wind turbines requires the use of modern high-strength fine-grained structural steels (Martin and Schroeter, 2005). This applies to wind turbines in terms of increasing turbine sizes as well as to maintenance and installation vessels and equipment (Ummenhofer et al., 2013). Without the demanded high load-bearing capacities and boom lengths, the economic realization of these goals would be inconceivable. During the assembly of high-strength steel structures, unacceptable defects can occasionally be found in the weld area, although the welding process was executed in accordance with the specifications. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Corresponding standards hardly provide any information on adequate repair concepts, and there is no uniform scientific data on which to base such concepts. This applies particularly to the consideration and optimization of welding-induced stresses due to the high shrinkage hindrance of the gouging grooves and degradation of the adjacent microstructures by gouging and re-welding. The result, especially in the case of high-strength steel grades, are frequently recurring imperfections as well as a missing consideration of the additionally induced welding stresses in the design of the structure. In this context, at BAM component-relevant investigations focused on welding residual stress evolution and microstructural degradation during repair of weld joints due to local thermal gouging and re-welding are carried out within the scope of a FOSTA project (P1311, IGF 20162N).
In this study, several relevant findings are discussed based on examples of structural engineering focusing on mechanical-technological properties and residual stresses, for instance found by (Schasse, 2017). Also experimental and numerical work as conducted by (Wongpanya, 2008) and weld tests under defined shrinkage restraint in special weld test-setups for research projects, e. g. FOSTA-P922 (Kannengiesser and Schroepfer, 2015) and P1011 (Kannengiesser and Schroepfer, 2017) have shown that an optimization of the welding-induced stresses of high-strength structural steels is specifically achievable by means of adapted heat control concepts (Schroepfer, 2017). The present research involves systematic investigations of influences of shrinkage restraint, the number of repair cycles and heat control during repair welding of the relatively new developed offshore-relevant high-strength steel S500MLO (EN 10225-1). For the quantification of the shrinkage restraint of weld joints, the concept of restraint intensity established by (Satho et al., 1973) was applied analogous to recent research, e. g. (Schwenk et al., 2008). By means of structural mechanics calculations, geometries of self-strained specimens were identified, that represent different defined rigidity conditions of repair welds of real components, cf. Fig. 1. It could be shown that with increasing weld joint restraint intensity significantly higher residual stresses in the weld metal and heat affected zone up to 80 % of the nominal yield strength occur, cf. Fig. 2. In relation to existing results, it has been shown that a safe repair of such welds can only be achieved by means of appropriate repair concepts and heat control taking the high welding stresses and special microstructures of high-strength steels into account.
Finally, the aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines, especially for SMEs, in order to avoid damage and, in most cases, expensive reworking and to improve the full utilization of the potential of high-strength steels.
T2 - Wind Energy Science Conference 2021
CY - Online meeting
DA - 25.05.2021
KW - High-strength structural steels
KW - Welding
KW - Repair
KW - Residual stresses
KW - Restraint
PY - 2021
AN - OPUS4-53319
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
T1 - Characterization of Hydrogen Diffusion in a Thick-walled Submerged Arc Multi-Layer Weld Joint
N2 - The energy production of the future will be dominated by CO2-emission free techniques like wind turbines and become essential in scope of the planned hydrogen economy. As onshore installation capacity is limited, the in-crease of the number of offshore wind turbines (OWT) is a major goal. In that connection, the OWTs continuously increase in size and weight and demand adequate foundations concepts like monopiles or tripods. These compo-nents are typically manufactured from welded mild steel plates with thickness up to 200 mm. The predominant welding technique is submerged arc welding (SAW) with up to five wires. In accordance with the standards, the occurrence of delayed hydrogen assisted cracking is anticipated by either a hydrogen removal heat treatment (HRHT) or a so-called minimum waiting time (MWT) before non-destructive testing (NDT) of the respective weld joint is allowed. The reason for the MWT is the necessary time for the hydrogen diffusion at ambient temperature due the high plate thickness. Both the effectiveness of a HRHT at elevated temperatures or the MWT at ambient temperature can be estimated by calculation of the diffusion time. This time depends on reliable hydrogen diffu-sion coefficients and these are rare in literature. For that reason, this study presents the hydrogen diffusion coef-ficients obtained from a multi-layer SAW joint of an offshore steel grade. Two different experimental techniques were used to identify the respective diffusion behavior: (1) hydrogen desorption experiments with a carrier gas hot extraction analyzer at elevated temperatures for the characterization of a HRHT and (2) the electrochemical permeation technique at ambient temperature for the characterization of an MWT. From both experiments, the respective diffusion coefficients were calculated. The obtained DCs are different from those reported in literature, i.e., the duration or applicability of a HRHT or MWT must be critically discussed.
T2 - European Congress and Exhibition on Advanced Materials and Process - Euromat 2021
CY - Online meeting
DA - 13.09.2021
KW - Welding
KW - Offshore
KW - Wind turbine
KW - Hydrogen
KW - Cracking
PY - 2021
AN - OPUS4-53296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Process-related influences and correlations in wire arc additive manufacturing of high-strength steels
N2 - High-strength fine-grained structural steels have great potential for weight-optimized, efficient structures in many modern steel applications. Further advances in efficiency can be achieved through additive manufacturing and bionic design. Commercial high-strength filler materials for wire arc additive manufacturing (WAAM) are already provided by the consumable producers. Today, application would be strictly limited due to absence of quantitative findings or any guidelines for the industry regarding welding-related stresses and component safety during manufacturing and service. Hence, process- and material-related influences and design-related restraint conditions associated with formation of residual stresses and cold cracking risk are investigated. The aim is the accessibility of special WAAM self-restraining cold cracking tests and easy applicable processing recommendations, enabling an economical, fit-for-purpose and crack-safe WAAM of high-strength steels. This first study focuses on determination of interactions between WAAM process parameters, resulting layer geometry, microstructure and residual stresses, analyzed via X-ray diffraction. Defined reference specimens are automated welded using a special WAAM solid wire (yield strength >820 MPa). Geometric properties can be specifically adjusted by wire feed and welding speed, but cannot be varied arbitrarily, since a high heat input causes local overheating, inadmissible changes of microstructure and mechanical properties, defects and comparable high tensile residual stresses.
T2 - 22. Werkstofftechnischen Kolloquium der TU Chemnitz
CY - Online meeting
DA - 24.03.2021
KW - Additive Manufacturing
KW - High-strength steel
KW - Residual stresses
PY - 2021
AN - OPUS4-53328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
T1 - Konstruktive Einflüsse bei der beanspruchungsgerechten Reparatur geschweißter Bauteile aus hochfesten Feinkornbaustählen
N2 - Bei der Montage von Stahlkonstruktionen kommt es trotz anforderungsgerechter schweißtechnischer Fertigung vereinzelt zur Detektion von unzulässigen Unregelmäßigkeiten im Schweißbereich. Die Verarbeitungsregelwerke empfehlen das lokale thermische Ausfugen betroffener Bereiche und erneutes Schweißen, geben aber aufgrund fehlender wissenschaftlich fundierter Untersuchungen kaum Informationen zu adäquaten Reparaturkonzepten. Dies betrifft insbesondere die Berücksichtigung und Optimierung resultierender schweißbedingter Beanspruchungen durch hohe Schrumpfbehinderungen der Ausfugenuten sowie der Gefügedegradation angrenzender Bereiche durch das Ausfugen und erneute Schweißen. Gerade bei hochfesten Stahlgüten ergeben sich dadurch häufig reduzierte mechanische Eigenschaften und zusätzliche schweißbedingte Beanspruchungen sowie erneut auftretende Nahtdefekte.
Deshalb sind für das Forschungsvorhaben systematische bauteilrelevante Untersuchungen der schweißbedingten Beanspruchungen und Gefügeveränderungen reparierter Schweißnähte in Abhängigkeit von der Schrumpfbehinderung und Wärmeführung beim Schweißen und Ausfugen sowie von der Reparaturzyklenanzahl geplant, mit dem Ziel Empfehlungen für beanspruchungs- und werkstoffgerechte Reparaturkonzepte abzuleiten. Hierfür sind gerade Analysen an hochfesten Stahlgüten S500 für den Offshore-Bereich und S960QL für den Mobilkranbau interessant, die zur Errichtung und Fertigung hocheffizienter Konstruktionen wie Windenergieanlagen notwendig sind. Die Erkenntnisse bieten eine Grundlage für entsprechende Normen und Regelwerke. Damit können letztlich Schäden und zumeist teure Nacharbeiten verhindert und eine verbesserte Ausnutzung des hohen Festigkeitspotentials hochfester Stähle erreicht werden. Gerade auch KMU können mit Blick auf die Kosten für Fertigung, Schweißarbeit und Material von den Erkenntnissen beim Einsatz hochfester Stähle, die für eine effiziente Realisierung der Energiewende in Deutschland notwendig sind, profitieren.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium der Otto-von-Guericke Universität Magdeburg
CY - Online meeting
DA - 17.06.2021
KW - Eigenspannungen
KW - Hochfest
KW - Feinkornbaustahl
KW - Reparatur
KW - Schweißen
PY - 2021
AN - OPUS4-53318
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Erste Untersuchungen auf dem Weg zum WAAM-Kaltrisstest für hochfeste Stähle
N2 - Hochfeste Feinkornbaustähle verfügen über ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. In dieser Präsentation werden erste Analysen des Einflusses der Fertigungsstrategie auf die Härte in additiv gefertigten Bauteilen aus hochfestem Stahl vorgestellt.
T2 - NA 092-00-05 GA (DVS AG Q 4/Q 4.1)
CY - Online meeting
DA - 10.03.2021
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Härteprüfung nach Vickers
PY - 2021
AN - OPUS4-53327
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Schweißen im Wasserstoffanlagen- und Behälterbau - Eine Kurzübersicht
N2 - Wasserstoff erfüllt die zentrale Rolle für die Umwandlung der bisherigen fossil-basierten Energieerzeugung und -nutzung auf eine dekarbonisierte, nachhaltige Form. Dazu muss der Wasserstoff erzeugt, gespeichert, transportiert werden, bevor er wieder der Nutzung zugeführt wird. Hierzu sind entlang der gesamtem Prozesskette Wasserstofftechnologien notwendig, die einen sicheren Betrieb erfordern. Hierbei kommt dem schweißtechnischen Anlagen- und Behälterbau wesentliche Bedeutung zu, insbesondere (aber nicht ausschließlich) für Speicherung und Transport des Wasserstoffes. Der vorliegende Beitrag gibt einen kurzen Überblick, wo und wie die konventionelle Schweißtechnik hierzu wichtige Beiträge leistet. Die additive Fertigung, also das „Drucken“ von Bauteilen wird dabei zunehmend wichtiger, entlang der gesamtem Prozesskette der Wasserstofftechnologien. Gleichwohl darf nicht unterschätzt werden, dass auch wesentlicher Bedarf an der Erweiterung und teilweiser Neufassung von bestehenden Regel- und Normenwerken besteht.
T2 - 51. Sondertagung "Schweißen im Behälter- und Anlagenbau"
CY - Munich, Germany
DA - 28.02.2023
KW - Wasserstoff
KW - Fügetechnik
KW - Schweißen
KW - Studie
PY - 2023
AN - OPUS4-57076
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Bericht zum Fortschritt des laufenden Projekts: „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“
N2 - Das DVS-Vorhaben 01.3211 „Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten“ ist ein Kooperationsprojekt der Bundesanstalt für Materialforschung und -prüfung (BAM) und dem Institut für Schweißtechnik und Trennende Fertigungsverfahren (ISAF) der Technischen Universität Clausthal. Das Übergeordnete Projektziel ist das Erlangen von Erkenntnissen für eine sichere und wirtschaftliche, kombinierte additive und abtragende Fertigung aus kostenintensiven Werkstoffen hochbelasteter Komponenten insbesondere für KMU. Dabei stehe die beiden Werkstoffe CoCr26Ni9Mo5W (2.4681) und FeNi36 (1.3912) im Fokus. Mittels Modifikation der Schweißzusätze sind homogen und isotrop ausgeprägte Werkstoffeigenschaften und eine Erhöhung der Prozessstabilität und Fertigungsfreiheitsgrade bei der additiven Fertigung erzielbar. Darüber hinaus wird der Einfluss nachfolgender abtragender Bearbeitungsschritte des ultraschallunterstützen und des konventionellen Fräsprozesses untersucht. Die mit dem Forschungsvorhaben verbundenen Nutzen für KMU sind die Stärkung der Innovationsfähigkeit und der Wirtschaftlichkeit sowie die Erhöhung der Wettbewerbsfähigkeit. In AP-3 wurden die Mikrostruktur der MSG-Schweißung der CoCr-Referenzlegierung untersucht. In AP-4 wurden Zerspanversuche an der MSG-Schweißung der CoCr-Referenzlegierung durchgeführt.
T2 - Sitzung des Fachausschusses 01 „Schweißmetallurgie und Werkstoffverhalten“ des DVS
CY - Aachen, Germany
DA - 22.02.2023
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
PY - 2023
AN - OPUS4-57175
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - In situ Messung chemischer Konzentrationen im Schmelzbad während des WIG-Schweißens von Duplexstählen zur Analyse der Phasenverteilung
N2 - Die Kombination aus hoher Korrosionsbeständigkeit und guten mechanischen Eigenschaften von Duplexstählen (DSS) ist auf ihre chemische Zusammensetzung und das ausgewogene Phasenverhältnis von Ferrit (α) und Austenit (γ) zurückzuführen.
Viele industrielle Anwendungen erfordern eine stoffschlüssige Verbindung von DSS. Das Wolfram-Inertgas-Schweißen (WIG) ist relativ einfach zu handhaben, benötigt nur wenig Platz und ermöglicht ein automatisiertes Schweißen, mit sehr hoher Reproduzierbarkeit und ist daher hervorragend zum Schweißen von DSS.
Während der Erstarrung dieser Dualphasenstähle kann es zu kritischen Phasenverhältnissen von α und γ kommen, was zu Erstarrungsrissen, Korrosionsanfälligkeit, geringerer Duktilität und kritischen Festigkeitswerten führt. Um die gewünschten Werkstoffeigenschaften zu erhalten, muss daher die α/γ-Verteilung zuverlässig vorhergesagt werden. Dies geschieht in der Regel mit Hilfe des WRC1992-Diagramms. Die Vorhersagegenauigkeit des Ferritgehalts in diesem Diagramm ist jedoch meist nicht genau genug und muss daher optimiert werden. Daher ist es notwendig, selbst kleinste Veränderungen in der chemischen Zusammensetzung des Schweißguts idealerweise während des Schweißens zu überwachen. Dies wird in diesen Experimenten mit Hilfe der laser-induzierten Plasmaspektroskopie (LIBS) durchgeführt. Ein großer Vorteil dieser Technik ist die hochgenaue zeit- und ortsaufgelöste Messung der chemischen Zusammensetzung während des Schweißens. In vorherigen Arbeiten wurde bereits die chemische Zusammensetzung im Schweißgut und der WEZ quantifiziert. In der präsentierten Untersuchung wird der Einfluss einzelner Elemente, wie Nb und Cu, auf das resultierende Schweißmikrogefüge untersucht.
T2 - Symposium Materialtechnik der TU Clausthal
CY - Clausthal, Germany
DA - 23.02.2023
KW - LIBS
KW - Duplex Stainless Steel
KW - WRC 1992 diagram
KW - TIG welding
PY - 2023
AN - OPUS4-57078
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schroeder, Nina
T1 - Influence of microalloying on precipitation behavior and notched impact strength of welded high-strength structural steels
N2 - This presentation summarizes the latest results on the microalloying influence on the preciptitation behavior on the mechanical properties of welded high-strength steel with a design yield strength of 690 MPa and above. For that reason, Charpy tests were performed for the pure weld metal and different heat-affected zones. Thermodynamic phase field modeling showed the usefulness of calculations in Thermocalc to predict the preciptiation behavior and (finally) to conclude the mechanistic behavior of the welded joint.
T2 - IIW Intermediate meeting of Commission II-A
CY - Garching, Germany
DA - 06.03.2023
KW - Welding
KW - High-strength steel
KW - Phase field modeling
KW - Preciptiates
KW - Microstructure characterization
PY - 2023
AN - OPUS4-57107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - WAAM process influences on local microstructure and residual stresses in high-strength steels
N2 - High-strength fine-grain structural steels have great potential for weight optimization of many modern engineering structures. Efficient manufacturing can be achieved here above all by Wire Arc Additive Manufacturing (WAAM). First commercial high-strength welding consumables for WAAM are already available. Due to a lack of knowledge and guidelines for the industry regarding welding residual stresses and component safety in manufacturing and operation, their application is still severely limited. Residual stresses play a crucial role here, as the special microstructure of high-strength steels is sensitive to cold cracking.
For this reason, process- and material-related influences, as well as the design effects on residual stress formation, are being investigated in a project funded by the AiF (FOSTA P1380/IGF 21162 BG). This study focuses on determining the interactions between heat control during WAAM process, resulting hardness, microstructure, and residual stresses, analyzed by X-ray diffraction. Welding experiments using geometrically similar AM specimens show that, with regard to the heat input, the energy per unit length in particular leads to significantly affected cooling times and microstructures and causes pronounced localized effects in terms of residual stresses in the upper weld beads.
T2 - 46th MPA-Seminar
CY - Stuttgart, Germany
DA - 12.10.2021
KW - Wire Arc Additive Manufacturing
KW - High-strength structural steels
KW - Vickers hardness
KW - Residual stresses
PY - 2021
VL - 46
SP - 296
EP - 306
PB - MPA-Stuttgart
AN - OPUS4-53571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Joining Processes in Hydrogen Technologies - Current need and future R&D activites, a review
N2 - This study gives an overview on the important field of joining processes for component fabrication in hydrogen technologies. For that reason, the current need and future research and developement activites are highlighted for the different technological field of hydrogen generation, storage, transport and use. In addition, the emerging field of additive manufacturing is included. Finally, some remarks are given for necessary changes in the standardization and its challenges.
T2 - 46th Seminar - Additive Manufacturing, Hydrogen, Energy, Integrity
CY - Online meeting
DA - 12.10.2021
KW - Hydrogen
KW - Joining process
KW - Welding
KW - Review
KW - Research and Development
PY - 2021
AN - OPUS4-53554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Griesche, Axel
T1 - The influence of hydrogen on strain-induced martensite formation and cracking in SMSS investigated simultaneously by ED-XRD and by X-ray radiography
N2 - Die Ergebnisse von in-situ Experimenten am Berliner Elektronenspeicherring (BESSY II) werden vorgestellt. Es wurden Zugversuche an wasserstoffbeladenen und wasserstofffreien supermartensitischen Proben durchgeführt und Diffraktionsspektren und radiographische Bilder aufgenommen. Die energiedispersive Röntgendiffraktion ermöglichte dabei in-situ die dehnungsinduzierte Phasenumwandlung von Restaustenit zu Martensit zu beobachten. Die Radiographiebilder der zerreisenden Probe gaben Einblicke in das Bruchverhalten in Abhängigkeit vom Wasserstoffgehalt.
T2 - 4th in-situ Workshop 2021 @ 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - Wasserstoffdegradation
KW - Snergiedispersive Röntgendiffraktion
KW - Zugversuch
KW - Röntgenradiographie
KW - Supermatensitischer Stahl
PY - 2021
AN - OPUS4-53697
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Erstellung von Tiefenprofilen auf Schweißnähten mittels Laserinduzierter plasmaspektroskopie (LIPS)
N2 - Duplexstähle sind hochlegierte, nichtrostende Stähle. Sie bieten aufgrund des ausgewogenen Phasenverhältnisses von Austenit und Ferrit einige physikalische Vorteile gegenüber anderen nichtrostenden Stählen. Beim Schweißen können sich durch die Kondensation von Schweißrauch und verdampftem Material verschiedene chemische Elemente auf der Oberfläche der erstarrten Schweißnaht anreichern. Dann ist die Bildung einer schützenden Chromoxidschicht nicht mehr gewährleistet und es kann an diesen Stellen zu Lochfraß kommen. Frühere Arbeiten haben gezeigt, dass die Anreicherung von Mangan und Chrom an der Oberfläche der Wärmeeinflusszone des geschweißten Edelstahls 304L mit LIBS gemessen werden kann. Wir stellen die Ergebnisse der Optimierung der LIBS-Parameter für präzise Dickenmessungen solcher dünnen Schichten und für Tiefenprofilmessungen vor. Dazu haben wir galvanisch beschichtete Kupferproben mit bekannten Schichtdicken verwendet. Die Mangankonzentration im Schweißgut ist reduziert. Dies hat einen großen Einfluss auf die metallografische Struktur des Materials.
T2 - BMDK der Universität Magdeburg
CY - Online Meeting
DA - 25.11.2021
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Evaporation
PY - 2021
AN - OPUS4-53821
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Investigation of the chemical element distribution on the surface of duplex stainless steel welds using laser-induced breakdown spectroscopy (LIBS)
N2 - Duplex steels are high-alloyed, stainless steels. They offer some physical advantages over other stainless steels due to the balanced phase ratio of austenite and ferrite. During welding processes, when welding fumes and vaporized material condensates, different chemical elements can accumulate on the surface of the solidified weld. Then, the formation of a protective chromium oxide layer is no longer guaranteed and pitting corrosion can occur at these places. Previous work has shown that the accumulation of manganese and chromium on the surface of the heat-affected zone of the welded high-grade steel 304L can be measured by LIBS.
We present the results of the optimization of LIBS parameters for precise thickness measurements of such thin films and for depth profile measurements Therefore, we used galvanically coated copper samples with known film thicknesses. The Concentration of manganese is reduced in the weld metal. This has a high impact on the metallografic structure of the material.
T2 - EMSLIBS 2021
CY - Online meeting
DA - 29.11.2021
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Evaporation
PY - 2021
AN - OPUS4-53869
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Einfluss der Wärmeführung auf die Eigenschaften und fertigungsbedingten Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle
N2 - Hochfeste Feinkornbaustähle verfügen über ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Kommerzielle hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Derzeit ist jedoch eine breite industrielle Anwendung insbesondere für KMU aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse untersucht. Im Fokus dieser Analysen steht die Bestimmung der Wechselwirkungen zwischen WAAM-Prozessparametern bzw. der Wärmeführung auf das Gefüge und die Eigenspannungen. Hierfür werden Referenzproben als offene Hohlquader mit definierten Abmessungen vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die gezielte Einstellung der geometrischen Eigenschaften erfolgt durch Schweißparameter und Nahtaufbau bei ca. 4 kg/h mittlerer Abschmelzleistung. Die Wärmeführung wird innerhalb eines statistischen Versuchsplanes mittels Streckenenergie (200 kJ/m bis 650 kJ/m) und Zwischenlagentemperatur (100 °C bis 300 °C) so variiert, dass die t8/5-Abkühlzeiten dem empfohlenen Verarbeitungsbereich entsprechen (ca. 5 s bis 20 s). Ziel ist es bei konstanten geometrisch-konstruktiven Randbedingungen, den Einfluss der Wärmeführung auf Gefüge und resultierende Eigenspannungen zu analysieren. Für die Streckenenergie können neben den Gefügeeinflüssen aufgrund der resultierenden Abkühlzeit deutliche Effekte insbesondere auf die lokalen Eigenspannungen im Bauteil belegt werden. Das Schweißen mit zu hoher Wärmeeinbringung bzw. Abschmelzleistung kann zu ungünstigen Gefüge- und Bauteileigenschaften führen, gleichzeitig jedoch niedrigere Zugeigenspannungsniveaus bewirken. Solche komplexen Wechselwirkungen gilt es letztlich mit diesen Untersuchungen zu klären, um leicht anwendbare Verarbeitungsempfehlungen und Normvorgaben für ein wirtschaftliches, anforderungsgerechtes und risssicheres WAAM von hochfesten Stählen den Anwendern zur Verfügung zu stellen.
T2 - DVS Congress 2021
CY - Online meeting
DA - 14.09.2021
KW - MAG-Schweißen
KW - Hochfester Stahl
KW - Eigenspannungen
KW - Additive Fertigung
KW - Kaltrisssicherheit
PY - 2021
SN - 978-3-96144-146-4
VL - 371
SP - 16
EP - 22
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-56669
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Becker, Amadeus
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Beanspruchungsgerechte Reparatur beim Bauteilschweißen hochfester Feinkornbaustähle
N2 - Eine nachhaltige und ressourceneffiziente Fertigung und Errichtung von Windenergieanlagen, sowohl auf See als auch an Land, erfordert zunehmend den Einsatz moderner hochfester Feinkornbaustähle. Werden nach dem Schweißen dieser hochfesten Konstruktionen unzulässige Defekte detektiert, sind nach geltenden Verarbeitungsrichtlinien die defekten Bereiche durch lokales Ausfugen und anschließendes Schweißen zu reparieren. Fehlende Informationen zu adäquaten Reparaturkonzepten in den Regelwerken bedingen oftmals eine unzureichende Berücksichtigung dabei auftretender zusätzlicher Beanspruchungen durch die erhöhte Schrumpfbehinderung der Ausfugenuten. Zusätzlich haben die ausführenden Betriebe vielfach kaum Kenntnis über die Degradation angrenzender Gefüge durch thermische Ausfugeprozesse und erneutes Schweißen, die in diesem Zusammenhang besonders bei den hochfesten Stählen als kritisch anzusehen sind. Das aktuelle Forschungsvorhaben der BAM (FOSTA P1311/IGF-Nr.20162N) fokussiert hierfür systematisch bauteilrelevante Untersuchungen zu den schweißbedingten Beanspruchungen und Gefügeveränderungen bei der Reparatur von hochfesten Schweißverbindungen. Wesentlich sind hierbei der Einfluss der Schrumpfbehinderung, der Wärmeführung beim Schweißen und Ausfugen sowie der Reparaturzyklenanzahl und die metallurgischen Aspekte bei den hochfesten Güten S500MLO für zukünftige Offshore-Anwendungen und S960QL für aktuelle Mobilkrananwendungen. Aufbauend auf einigen Studien zur schweißbedingten Beanspruchung hochfester Stähle zeigt der vorliegende Beitrag die Identifikation geeigneter Probengeometrien und Schweißdetails mittels numerischer und experimenteller Analysen. Dadurch wird die Übertragbarkeit der vorgestellten Schweißexperimente und Ergebnisse hinsichtlich der resultierenden Schweißeigenspannungen auf reale Reparaturfälle im Bereich des hochfesten Stahlbaus sichergestellt. Es zeigt sich in Übereinstimmung mit früheren Ergebnissen eine signifikante Erhöhung der Beanspruchungen an den variierten schlitzförmigen Prüfnähten. Das Eigenspannungsniveau sowohl im Schweißgut als auch in der WEZ korreliert mit dem Einspanngrad. Mit dem Ziel beanspruchungs- und werkstoffgerechte Reparaturkonzepte zu erarbeiten, sind zum einen geringere Wärmeinbringungen, besonders durch niedrige Zwischenlagentemperaturen und Einspannbedingungen anzustreben, um hohe Beanspruchungen und kritische Gefügedegradationen im Reparaturbereich zu vermeiden. Dies wird durch systematische Untersuchungen zum Ausfugen und Schweißen sowie letztlich dem Transfer von Verarbeitungsempfehlungen für die Anwender und Richtlinien erreicht.
T2 - DVS Congress 2021
CY - Online meeting
DA - 14.09.2021
KW - MAG-Schweißen
KW - Reparatur
KW - Eigenspannungen
KW - Hochfester Stahl
KW - Thermisches Ausfugen
KW - Windenergie
KW - Gefügedegradation
PY - 2021
SN - 978-3-96144-146-4
VL - 371
SP - 285
EP - 292
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-56666
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Härtel, S.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Einfluss der Wärmeführung auf die Eigenschaften und fertigungsbedingten Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle
N2 - Hochfeste Feinkornbaustähle verfügen über ein großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Kommerzielle hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Derzeit ist jedoch eine breite industrielle Anwendung insbesondere für KMU aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse untersucht. Im Fokus dieser Analysen steht die Bestimmung der Wechselwirkungen zwischen WAAM-Prozessparametern bzw. der Wärmeführung auf das Gefüge und die Eigenspannungen. Hierfür werden Referenzproben als offene Hohlquader mit definierten Abmessungen vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die gezielte Einstellung der geometrischen Eigenschaften erfolgt durch Schweißparameter und Nahtaufbau bei ca. 4 kg/h mittlerer Abschmelzleistung. Die Wärmeführung wird innerhalb eines statistischen Versuchsplanes mittels Streckenenergie (200 kJ/m bis 650 kJ/m) und Zwischenlagentemperatur (100 °C bis 300 °C) so variiert, dass die t8/5-Abkühlzeiten dem empfohlenen Verarbeitungsbereich entsprechen (ca. 5 s bis 20 s). Ziel ist es bei konstanten geometrisch-konstruktiven Randbedingungen, den Einfluss der Wärmeführung auf Gefüge und resultierende Eigenspannungen zu analysieren. Darüber hinaus erfolgt die Bestimmung des Einflusses der t8/5-Abkühlzeit auf die mechanisch-technologischen Eigenschaften des speziellen, hochfesten WAAM-Massivdrahts mithilfe von Dilatometeranalysen. Für die Streckenenergie können neben den Gefügeeinflüssen aufgrund der resultierenden Abkühlzeit deutliche Effekte insbesondere auf die lokalen Eigenspannungen im Bauteil belegt werden. Das Schweißen mit zu hoher Wärmeeinbringung bzw. Abschmelzleistung kann zu ungünstigen Gefüge- und Bauteileigenschaften führen, gleichzeitig jedoch niedrigere Zugeigenspannungsniveaus bewirken. Die Dilatometeranalysen zeigen für den untersuchten WAAM-Schweißzusatzwerkstoff eine großes t8/5-Zeitfenster mit einer vergleichsweise geringen Abnahme der Zugfestigkeit mit zunehmender t8/5-Abkühlzeit. Solche komplexen Wechselwirkungen gilt es letztlich mit diesen Untersuchungen zu klären, um leicht anwendbare Verarbeitungsempfehlungen und Normvorgaben für ein wirtschaftliches, anforderungsgerechtes und risssicheres WAAM von hochfesten Stählen den Anwendern zur Verfügung zu stellen.
T2 - 42. Assistentenseminar Fügetechnik
CY - Brunswick, Germany
DA - 06.10.2021
KW - MAG-Schweißen
KW - Hochfester Stahl
KW - Eigenspannungen
KW - Additive Fertigung
KW - Kaltrisssicherheit
PY - 2022
SN - 978-3-96144-210-2
VL - 385
IS - 42
SP - 94
EP - 101
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-56642
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Einfluss von Wärmeführung und Bauteildesign auf die Beanspruchungen additiv geschweißter hochfester Feinkornbaustähle
N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für additives MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf die Abkühlbedingungen, Gefüge, mechanisch-technologischen Eigenschaften und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung und Probenabmessungen werden innerhalb eines statistischen Versuchsplans variiert. Die Schweißwärmeführung wird dabei so eingestellt, dass die t8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) sichergestellt sind. Hierzu ließen sich über zusätzliche thermo-physikalische Umformsimulationen mittels Dilatometer die komplexen Wärmezyklen abbilden und die resultierende Zugfestigkeit des Schweißgutes bestimmen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein.
T2 - DVS Congress 2022
CY - Koblenz, Germany
DA - 19.09.2022
KW - WAAM
KW - Eigenspannungen
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Kaltrisssicherheit
KW - Windenergie
KW - Wärmeführung
PY - 2022
AN - OPUS4-56718
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Influence of the WAAM process and design aspects on residual stresses in high-strength structural steels
N2 - High-strength fine-grain structural steels have great potential for weight optimization of many modern engineering structures. Efficient manufacturing can be achieved here above all by Wire Arc Additive Manufacturing (WAAM). First commercial high-strength welding consumables for WAAM are already available. However, due to a lack of knowledge and guidelines for the industry regarding welding residual stresses and component safety in manufacturing and operation, their application is still severely limited. Residual stresses play a crucial role here, as the sensitive microstructure of high-strength steels carries a high risk of cold cracking. For this reason, process- and material-related influences, as well as the design aspects on residual stress formation and the risk of cold cracking, are being investigated in a recent project (FOSTA-P1380/IGF21162BG). This high strength of the WAAM welding consumables is adjusted via a martensitic phase transformation. The volume expansion associated with martensite formation has a significant influence on residual stress evolution. However, this has not yet been investigated in relation to the processing of high-strength steels by WAAM. The aim of this work is to establish a WAAM cold crack test and easy-to-apply processing recommendations that will allow economical, expedient, and crack-resistant fabrication of high-strength steels, especially for SME. This paper focuses on the analysis of the effects of welding heat control and design of WAAM components on cooling conditions, microstructure, mechanical-technological properties and residual stresses. For this purpose, geometrically defined specimens (hollow cuboids) are welded fully automatically with a special, high-strength WAAM solid wire (yield strength >790 MPa). The heat control and specimen dimensions are varied within a statistical experimental design. The weld heat control is adjusted in such a way that the t8/5 cooling times are ensured within the recommended processing range (approx. 5–20 s). For this purpose, additional thermo-physical forming simulations using a dilatometer allowed the complex heat cycles to be reproduced and the resulting ultimate tensile strength of the weld metal to be determined. The WAAM welding of complex geometries with varying welding heat control and geometric factors or wall thicknesses not only has an effect on the cooling conditions, cooling times and microstructure, but also has a significant influence on the structural restraint conditions during welding. Hence, the welding experiments show significant effects of specimen scaling and heat input on the welding residual stresses, which may be detrimental regarding component properties and crack-critical tensile residual stresses. These complex interactions are analyzed within this investigation
T2 - 75th IIW Annual Assembly (Subcomission IIA)
CY - Online meeting
DA - 17.07.2022
KW - WAAM
KW - Residual Stresses
KW - High-strength Steels
KW - Cold cracking safety
KW - Wind energy
KW - Heat control
PY - 2022
AN - OPUS4-56715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Legierungsmodifikation und Einsatz hybrider Fräsprozesse zur Optimierung der Zerspanungssituation Ni-basierter Verschleißschutzauftragschweißungen mit definierten Oberflächen
N2 - Die Ziele zur Verringerung der CO2-Emissionen sind eng verknüpft mit der Entwicklung hocheffizienter und wirtschaftlicher Komponenten aus Stahl in der Anlagen-, Verfahrens- und Kraftwerktechnik, die für hohe kombinierte korrosive, tribologische, thermische und mechanische Beanspruchungen auf Anwendungsfall und Stahlwerkstoff abgestimmte Verschleißschutzschichten erfordern. Neben zunehmender Forderungen infolge des Preis- und Lieferrisikos konventionelle Kobalt- durch Nickellegierungen zu ersetzen, wächst in der Industrie der Bedarf nach definierten Oberflächen hoher Güte bzw. Funktionsflächen für die Schutzschichten. Eine für Bauteile mit komplexer Geometrie erforderliche Fräsbearbeitung ist insbesondere für KMU aufgrund hohen Werkzeugverschleißes oftmals nicht wirtschaftlich realisierbar, jedoch für viele Einsatzfälle dringend notwendig.
Es soll daher mittels Legierungsmodifikationen an Schweißzusätzen für nickelbasierte plasmaauftraggeschweißte Verschleißschutzschichten und durch Einsatz innovativer ultraschallunterstützter Fräsprozesse eine günstigere Zerspanbarkeit erreicht werden, ohne das Verschleißschutzpotential zu mindern.
Im vorliegenden Beitrag wird die Methodik für die Untersuchungen der Wechselwirkung zwischen der mittels Legierungsmodifikation eingestellten Gefüge- bzw. Ausscheidungsmorphologie und der durch Ultraschalloszillation unterstützten Zerspanungskinetik mittels hochinstrumentierter Fräsversuche vorgestellt. In-situ-Messungen auftretender Prozesskräfte (mittels Dynamometer), Oszillationen (mittels Laser-Vibrometer) und Temperaturen (mittels Hochgeschwindigkeitspyrometer) an der Werkzeugschneide sowie der anschließenden Untersuchungen von Werkzeugverschleiß und Oberflächenintegrität (Rauheit, Degradationen, fertigungsbedingte Beanspruchungen) ermöglichen eine detaillierte, reproduzierbare Analyse und Korrelation zwischen den mikrostrukturellen Eigenschaften und der Zerspanbarkeit. Unter systematischer Anwendung dieser Methodik sowie der Berücksichtigung der Anbindung zum Stahlsubstratwerkstoff und der Wirksamkeit des Verschleißschutzes lässt sich letztlich eine gezielte Optimierung der Zerspanungssituation erreichen.
T2 - Tagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
PY - 2022
AN - OPUS4-56626
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Tool development for hybrid finishing milling of iron aluminides
N2 - The importance of high-temperature materials made of iron aluminides (FeAl) has been increasing in light weight applications, e.g., airplane turbines, due to the high material’s specific strength. However, the highly economic production by means of permanent mold casting involves special microstructures for Fe26Al4Mo0.5Ti1B alloy components leading to difficult machinability for subsequent finishing milling and low surface qualities. Major effects of tool and machining parameter variation incorporating ultrasonic assistance on the milling process and surface integrity are shown. Loads for tool and component surface are significantly adjustable to enable an economic process chain regarding the surface integrity of safety-relevant components.
T2 - 6th CIRP Conference on Surface Integrity 2022, Lyon, 06
CY - Lyon, France
DA - 08.06.2022
KW - Ultrasonic-assisted milling
KW - Iron aluminide
KW - Surface integrity
KW - Tool wear
PY - 2022
AN - OPUS4-56630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Verschleißschutz durch Hartphasenauftragschweißungen mit spanend bearbeiteten Funktionsflächen
N2 - Das Schlichtfräsen von Verschleißschutzlegierungen ist aufgrund hohen Werkzeugverschleißes vor allem für KMU oftmals nicht wirtschaftlich. Durch gezielte Legierungsmodifikationen sowie den Einsatz hybrider Fertigungsprozesse wie dem ultraschallunterstützten Fräsen soll die Zerspanbarkeit der Legierungen verbessert werden. In dieser Präsentation werden erste Ergebnisse zu Voruntersuchungen zu der Legierung und den Einfluss auf das Werkzeug gezeigt.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Magdeburg, Germany
DA - 14.12.2022
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
PY - 2022
AN - OPUS4-56623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Projektkurzvorstellung FOSTA P1550: Beitrag zur sicheren Verarbeitung beim Verschleißschutz hochbelasteter Stahlbauteile
N2 - Die Ziele zur Verringerung der CO2-Emissionen sind eng verknüpft mit der Entwicklung hocheffizienter und wirtschaftlicher Komponenten aus Stahl in der Anlagen-, Verfahrens- und Kraftwerktechnik, die für hohe kombinierte korrosive, tribologische, thermische und mechanische Beanspruchungen auf Anwendungsfall und Stahlwerkstoff abgestimmte Verschleißschutzschichten erfordern. Neben zunehmender Forderungen infolge des Preis- und Lieferrisikos konventionelle Kobalt- durch Nickellegierungen zu ersetzen, wächst in der Industrie der Bedarf nach definierten Oberflächen hoher Güte bzw. Funktionsflächen für die Schutzschichten. Eine für Bauteile mit komplexer Geometrie erforderliche Fräsbearbeitung ist insbesondere für KMU aufgrund hohen Werkzeugverschleißes oftmals nicht wirtschaftlich realisierbar, jedoch für viele Einsatzfälle dringend notwendig.
Es soll daher mittels Legierungsmodifikationen an Schweißzusätzen für nickelbasierte plasmaauftraggeschweißte Verschleißschutzschichten und durch Einsatz innovativer ultraschallunterstützter Fräsprozesse eine günstigere Zerspanbarkeit erreicht werden, ohne das Verschleißschutzpotential zu mindern.
T2 - NA 092-00-05 GA "Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)"
CY - Online meeting
DA - 12.03.2022
KW - Verschleißschutz
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
PY - 2022
AN - OPUS4-56636
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Eissel, A.
A1 - Treutler, K.
A1 - Wesling, V.
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die additive Fertigung mittels Schweißverfahren bietet große ökonomische Vorteile für eine ressourceneffiziente Bauteilherstellung. Offene Fragen bezüglich Homogenität, Anisotropie der Schweißgefüge und den damit verbundenen Bauteileigenschaften stehen einer wirtschaftlichen Verarbeitung oftmals im Wege. Finale Bauteilgeometrie und Oberflächengüte erfordern meist komplementäre subtraktive Fertigungsschritte. Werkstoffe für hochbelastbare Komponenten sind oftmals schwer spanbar. In einem Vorhaben der BAM und des ISAF wurde untersucht, wie die Modifikation der AM-Schweißzusätze und das ultraschallunterstützte Fräsen (US) die Zerspanungssituation verbessern. Der vorliegende Artikel stellt wesentliche Zusammenhänge zwischen Legierung, Gefüge und Zerspanung zweier schwer spanbarer Hochleistungslegierungen (FeNi und CoCr) dar. Großes Potenzial zeigte neben dem US die Modifikation mit Zr und Hf bei Zulegierung in das Schweißgut mittels Beschichtung von Massivdrähten bzw. Herstellung von Fülldrähten.
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
KW - Metallschutzgasschweißen
PY - 2024
VL - 76
IS - 1-2
SP - 8
EP - 13
PB - DVS-Media GmbH
CY - Düsseldorf
AN - OPUS4-59463
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Residual stress formation in DED-arc manufactured high strength steel components
N2 - Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
T2 - IIW Intermediate Meeting 2023 CII and CIX
CY - Munich, Germany
DA - 06.03.2023
KW - WAAM
KW - Residual Stresses
KW - High-strength Steels
KW - Microstructure
KW - Cold cracking safety
KW - Wind energy
PY - 2023
AN - OPUS4-59261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Einfluss trennender Fertigungsschritte auf die Eigenspannungen in Bauteilen aus hochfestem Stahl
N2 - Der Vortrag gibt einen Überblick über den Einfluss
Trennender Fertigungsschritte auf die Eigenspannungen in einer Schweißverbindung und an additiv gefertigten Bauteilen aus hochfestem Stahl. Es wird dargestellt, wie die Spanende Bearbeitung in Wechselwirkung mit der lokalen Mikrostruktur die Eigenspannungen beeinflusst.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium OvGU Magdeburg
CY - Magdeburg, Germany
DA - 17.01.2024
KW - Hochfester Stahl
KW - Additive Fertigung
KW - Reparaturschweißen
KW - Eigenspannungen
PY - 2024
AN - OPUS4-59413
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Neutronen- und Röntgendiffraktion Zur Einflussanalyse des Bauteil-Designs auf die Eigenspannungen bei der additiven Fertigung mit hochfestem Stahl
N2 - Der Vortrag gibt einen Überblick über die mittels XRD und Neutronenbeugung ermittelten Eigenspannungen in additiv gefertigten Bauteilen. Zusätzliche wird der Einfluss von Geometrieparameters auf de Eigenspannungen betrachtet
T2 - Sitzung DIN NA 092-00-05 GA
CY - Berlin, Germany
DA - 15.03.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
AN - OPUS4-59236
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Minimization of tool wear in milling of iron aluminides using ultrasonic-assisted process
N2 - Presentation of key results from the ZIM cooperation project "TEWUFEAL" on tool development for ultrasonic-assisted milling of iron aluminide alloys cast in gravity die casting.
T2 - 24th International Conference on Wear of Materials
CY - Banff, Canada
DA - 16.04.2023
KW - Iron aluminides
KW - Ultrasonic-assisted milling
KW - Surface integrity
KW - Tool wear
PY - 2023
AN - OPUS4-59259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
T1 - Diffusionsmessungen in UP-Mehrlagenschweißgut als effektives Tool gegen verzögerte Kaltrissbildung in Dickblechschweißungen
N2 - Offshore-Windenergieanlagen bilden einen zentralen Bestandteil der zukünftigen Energieerzeugung. Hierzu notwendige Gründungs- und Turmstrukturen werden vorrangig aus UP-geschweißten Blechen aus hochfesten niedriglegierten Stählen mit Dicken bis zu 200 mm hergestellt. Die großen Blechdicken begünstigen hohe Schweißeigenspannungen und lange Diffusionswege für z. B. über den Schweißprozess eingebrachten Wasserstoff. Damit steigt das Risiko für eine wasserstoffunterstützte Kaltrissbildung (WKB) an. Zum sichereren Ausschluss von WKB in den geschweißten Komponenten wird in Abhängigkeit der Nahtgröße, Wärmeeinbringung und Stahlsorte eine Mindestwartezeit (MWZ) von bis zu 48 h empfohlen, bevor die zerstörungsfreie Prüfung durchgeführt wird. Es ist allerdings offen, ob die empfohlene MWZ zu konservativ ist. Einflüsse sind hier bspw. die schwierige Bewertung des Wasserstoffdiffusionsverhaltens im heterogenen UP-Mehrlagen-Schweißgut (SG) im Vergleich zum Grundwerkstoff (GW).
Zudem sind nur sehr begrenzt H-Diffusionskoeffizienten für UP-Mehrlagen-SG als Grundlage zur Abschätzung des Zeitintervalls einer möglichen verzögerten Kaltrissbildung (somit MWZ) oder auch für Nachwärmprozeduren zur Wasserstoffreduktion (keine MWZ) verfügbar. Verlässliche H-Diffusionskoeffizienten sind daher ein adäquates Tool zur Bewertung des Risikos einer verzögerten WKB. Dieser Beitrag beschreibt Untersuchungen zur Charakterisierung der Wasserstoffdiffusionsverhalten in UP-Mehrlagen-SG eines 60 mm dicken Bleches einer Offshore-Stahlgüte.
Dazu wurden Proben unterschiedlicher Dicke aus dem reinen Schweißgut extrahiert und über elektrochemische Permeation und Trägergasheißextraktion im Temperaturbereich bis 400 °C sehr interessante Ergebnisse zu den korrespondierenden Diffusionskoeffizienten erarbeitet.
T2 - DVS Congress 2021
CY - Online meeting
DA - 14.09.2021
KW - UP-Schweißen
KW - Wasserstoff
KW - Kaltriss
KW - Permeation
KW - Diffusion
PY - 2021
SN - 978-3-96144-146-4
VL - 371
SP - 448
EP - 459
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-53369
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Joining processes for components in hydrogen technologies: Current need and future importance
N2 - This presentation gives an overview on the importance of joining processes for component fabrication in hydrogen technologies. For that reason, the current need and future research and developement activites are highlighted for the three technological fields: hydrogen storage, transport and use (in terms of the emerging field of additive manufacturing). Finally, some remarks are given for necessary changes in the standardization.
T2 - IIW Intermediate Meeting, Comm. II-A "Welding Metallurgy"
CY - Online meeting
DA - 17.03.2022
KW - Hydrogen
KW - Welding
KW - Research
KW - Review
KW - Additive manufacturing
PY - 2022
AN - OPUS4-54488
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Fügetechnik für die neue Wasserstoffökonomie
N2 - Die Herausforderungen für die Fügetechnikbranche, die sich durch die neuen Wasserstoff-Technologiefelder „Erzeugung“, „Speicherung“, „Transport“ und „Nutzung“ ergeben, sind sehr vielfältig. Der DVS-Bericht 373 gibt dazu einen tieferen Einblick. Der hier vorliegende Kurzbericht stellt dazu ausgewählte Praxisbeispiele, zugehörige Herausforderungen und sich ergebende Chancen vor. Fügetechnologien haben dabei wesentliche Bedeutung für das erfolgreiche Umsetzen und Herstellen der benötigten technischen Komponenten, wie anhand der Themenkomplexe „Wasserstoff-Pipelines“ und „additive Fertigung“ betrachtet wird. Zudem ergeben sich Herausforderungen für die notwendigen Regelwerke und Normen, die nahezu vollständig angepasst oder geschaffen werden müssen.
KW - Wasserstoff
KW - Fügetechnik
KW - Studie
KW - Werkstoffe
KW - Schweißen
PY - 2022
UR - https://www.schweissenundschneiden.de/artikel/fuegetechnik-fuer-die-neue-wasserstoffoekonomie
SN - 0036-7184
VL - 74
IS - 3
SP - 142
EP - 144
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-54563
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Bericht zum Fortschritt des laufenden Projekts: "Entwicklung von Wärmenachbehandlungskonzepten zur Vermeidung von Spannungsrelaxationsrissen"
N2 - Dieses Dokument fasst den Projekfortschritt des BAM-Projektes "Entwicklung von Wärmenachbehandlungsstrategien zur Vermeidung von Spannungsrelaxationsrissen" im Rahmen des Fachausschusses 1 "Schweißmetallurgie" des DVS e.V. für das Projektjahr 2021 zusammen und stellt die wichtigsten Ergebnisse in Kurzform vor.
T2 - Sitzung des FA1 "Schweißmetallurgie" der Forschungsvereinigung Schweißen und verwandte Verfahren des DVS e.V.
CY - Online meeting
DA - 22.03.2022
KW - UP-Schweißen
KW - Spannungsrelaxationsriss
KW - Wärmenachbehandlung
KW - Eigenspannungen
KW - Schallemissionsanalyse
PY - 2022
AN - OPUS4-54525
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Chemical Concentrations in the weld pool measured in situ by Laser-Induced Breakdown Spectroscopy (LIBS) during GTAW
N2 - Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). We could quantitatively measure the chemical composition in the weld seam of various DSS and identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material.
T2 - IIW joint intermediate meeting Comm.I,IV,XII_2022_ON-LINE
CY - Online Meeting
DA - 21.03.2022
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
PY - 2022
AN - OPUS4-54527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Consideration of manufacturing-related stresses and cold crack avoidance in high-strength steels WAAM components
N2 - High-strength steels offer great potential in weight-optimised modern steel structures. Additive manufacturing processes, such as Wire Arc Additive Manufacturing (WAAM), enable near-net-shape manufacturing of complex structures and more efficient manufacturing, offering significant savings in costs, time, and resources. Suitable filler materials for WAAM are already commercially available. However, the lack of knowledge or technical guidelines regarding welding residual stresses during manufacturing and operation in connection with cold cracking risk limit their industrial application significantly. In a project of BAM and TU Chemnitz, the influences and complex interactions of material, manufacturing process, design and processing steps on residual stress evolution are investigated. By developing process recommendations and a special cold cracking test, economic manufacturing, and stress-appropriate design of high-strength steel WAAM components are main objectives.
The present study focuses on determining the influence of heat control (interpass temperature, heat input, cooling time) and the design aspects of the components on the hardness and residual stresses, which are analysed by X-ray diffraction. Defined reference specimens, i.e., hollow cuboids, are automatically welded with a special WAAM solid wire. The influences of wall length, wall thickness and wall height on the residual stresses are analysed. Geometric properties can be selectively adjusted by wire feed and welding speed but cannot be varied arbitrarily. This was addressed by adapted build-up strategies. The results indicate a significant influence of the heat control and the wall height on the residual stresses. The interpass temperature, wall thickness and wall length are not significant. These analyses allow recommendations for standards and manufacturing guidelines, enabling a safe and economic manufacturing of high-strength steel components.
T2 - European Steel Technology and Application Days
CY - Düsseldorf, Germany
DA - 14.06.2023
KW - DED-arc
KW - Additive manufacturing
KW - Heat control
KW - High-strength filler metals
KW - Residual stress
PY - 2023
AN - OPUS4-57691
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Einfluss trennender Fertigungsschritte auf die Eigenspannungen in additiv gefertigten Bauteilen aus hochfestem Stahl
N2 - Additive Fertigungsverfahren wie das Wire Arc Additive Manufacturing (WAAM) ermöglichen die effiziente Fertigung von gewichtsoptimierten endkonturnahen Strukturen in modernen Stahlkonstruktionen. Ihre Effizienz kann weiter durch die Verwendung von hochfesten Stählen gesteigert werden. Dies erlaubt eine signifikante Einsparung von Kosten, Zeit und Ressourcen. Entsprechende Schweißzusatzwerkstoffe für Lichtbogenschweißverfahren sind kommerziell verfügbar. Fehlende Richtlinien und fehlende quantitative Kenntnisse über die schweißtechnische Beanspruchung während der Fertigung und im Betrieb limitieren den industriellen Einsatz stark. Daher werden in einem aktuellen Vorhaben (IGF-Nr. 21162 BG) der BAM und TU Chemnitz die wesentlichen Einflüsse und komplexen Interaktionen durch Werkstoff, Fertigungsprozess, Konstruktion und trennende Fertigungsschritte auf den Beanspruchungszustand untersucht. Der vorliegende Beitrag fokussiert hierfür die Auswirkungen trennender Fertigungsschritte auf Verzug und Eigenspannungen definierter WAAM-Prüfkörper. Die Eigenspannungsanalyse erfolgt mittels Röntgenbeugung. Die große Anzahl an Ergebnissen von zuvor untersuchten Referenzproben, die mit einem speziellen WAAM-Massivdraht (Streckgrenze >820 MPa) bei unterschiedlicher Wärmeführung und Geometrie vollautomatisiert geschweißt wurden, lässt eine Korrelation der Messdaten zu. Hierzu erfolgt die Analyse des Ausgangszustandes und abschließend des Zustandes nach trennender Bearbeitung, welche begleitend mittels digitaler Bildkorrelation hinsichtlich des Verzuges untersucht wurden. So ist zu beobachten, dass die Geometrie deutlichen Einfluss auf Relaxation und Umlagerung der Eigenspannungen hat und damit die Risssicherheit positiv beeinflussen kann.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium OvGU Magdeburg
CY - Magdeburg, Germany
DA - 31.05.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
AN - OPUS4-57689
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Neutronen- und Röntgendiffraktion zur Einflussanalyse des Bauteil-Designs auf die Eigenspannungen bei der additiven Fertigung mit hochfestem Stahl
N2 - Vorstellung und Gegenüberstellung von Eigenspannungsanalysen mittels Röntgen- und Neutronenbeugung an einer additiven Prüfgeometrie aus hochfestem Stahl.
Einflussanalyse des Designs (Länge, Höhe, Wandstärke) von additiv gefertigten Bauteilen aus hochfestem Stahl auf die Eigenspannungen.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium OvGU Magdeburg
CY - Magdeburg, Germany
DA - 25.01.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
AN - OPUS4-57688
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Korrelation von Wärmeführung, Nahtgeometrie, Bauteildesign und Eigenspannungen bei DED-Arc mit hochfesten Zusatzwerkstoffen
N2 - Hochfeste Feinkornbaustähle verfügen über großes Potenzial für gewichtsoptimierte, effiziente Strukturen in vielen modernen Stahlkonstruktion. Weitere Effizienzsteigerungen können durch additives Fertigen sowie bionische Bauweisen erreicht werden. Hochfeste Zusatzwerkstoffe für formgebendes MSG-Schweißen (engl.: Wire Arc Additive Manufacturing, WAAM) sind bereits von den Schweißzusatzherstellern lieferbar. Eine breite industrielle Anwendung insbesondere für KMU ist aufgrund fehlender quantitativer Erkenntnisse und Richtlinien bezüglich schweißbedingter Beanspruchungen und Bauteilsicherheit während der Herstellung und des Betriebs derzeit stark limitiert. In einem gemeinsamen Forschungsprojekt (FOSTA-P1380/IGF21162BG) der BAM und der TU Chemnitz werden daher die mit Eigenspannungsausbildung und der Gefahr einer Kaltrissbildung verbundenen prozess- und werkstoffbedingten sowie konstruktiven Einflüsse beim WAAM hochfester Stähle untersucht. Der vorliegende Beitrag fokussiert die Analyse der Auswirkungen von Schweißwärmeführung und Design der WAAM-Bauteile auf Nahtgeometrie, Materialausnutzung und Eigenspannungen. Hierfür werden geometrisch definierte Probenkörper (Hohlquader) vollautomatisiert mit einem speziellen, hochfesten WAAM-Massivdraht (Streckgrenze >790 MPa) geschweißt. Die Wärmeführung wird innerhalb eines statistischen Versuchsplans so variiert, dass die Dt8/5-Abkühlzeiten im empfohlenen Verarbeitungsbereich (ca. 5 s bis 20 s) liegen. Das WAAM-Schweißen komplexer Geometrien mit variierenden Schweißwärmeführungen und geometrischen Verhältnissen bzw. Wanddicken bedingt neben den Auswirkungen auf die Abkühlbedingungen, Abkühlzeiten und Gefüge deutliche Einflüsse auf die konstruktiven Steifigkeitsverhältnisse beim Schweißen. Es zeigen sich anhand der Schweißexperimente signifikante Auswirkungen durch Probenskalierung und Wärmeeinbringung auf die resultierenden lokalen Eigenspannungen. Die Folge können ungünstige Bauteileigenschaften und risskritische Zugeigenspannungen sein.
T2 - 43. Assistentenseminar Füge- und Schweißtechnik 2022
CY - Chemnitz, Germany
DA - 27.09.2022
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
VL - 386
SP - 1
EP - 7
PB - DVS Media
CY - Düsseldorf
AN - OPUS4-59232
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Gräbner, Maraike
A1 - Treutler, Kai
A1 - Wesling, Volker
T1 - Legierungsmodifikation und Einsatz hybrider Fräsprozesse zur Optimierung der Zerspanungssituation Ni-basierter Verschleißschutzauftragschweißungen mit definierten Oberflächen
N2 - Die Verringerung der CO2-Emissionen ist eng mit der Entwicklung hocheffizienter und wirtschaftlicher Komponenten aus Stahl in der Anlagen- und Verfahrenstechnik verknüpft. Um den hohen kombinier-ten korrosiven, tribologischen, thermischen und mechanischen Beanspruchungen stand zu halten, werden auf Anwendungsfall und Stahlwerkstoff abgestimmte Verschleißschutzschichten eingesetzt. Neben der zunehmenden Forderung konventionelle Kobalt- durch Nickellegierungen zu ersetzen, wächst auch der Bedarf nach definierten Ober- bzw. Funktionsflächen hoher Güte. Aufgrund hohen Werkzeugverschleißes ist die erforderliche Fräsbearbeitung zu Herstellung der komplexen Geomet-rien der Bauteile für KMU oftmals wirtschaftlich nicht möglich. Mittels Legierungsmodifikation der Schweißzusätze für nickelbasierte plasmaauftraggeschweißte Verschleißschutzschichten und durch den Einsatz innovativer ultraschallunterstützter Fräsprozesse soll eine günstigere Zerspanbarkeit er-reicht werden, ohne das Verschleißschutzpotential zu mindern. Im vorliegenden Beitrag wird der Ein-fluss der mittels Legierungsmodifikation eingestellten Gefüge- und Ausscheidungsmorphologie auf die Zerspanbarkeit untersucht. Dies erfolgt anhand einer typischerweise für Schneckenmaschinen einge-setzten Verschleißschutzlegierung NiCrMoSiFeB-Legierung („Colmonoy 56 PTA“), die konventionelle CoCr-Legierungen (Stellite) substituiert. Metallurgische Untersuchungen und In-situ-Messungen auf-tretender Prozesskräfte an der Werkzeugschneide beim Fräsen sowie anschließende Untersuchungen von Werkzeugverschleiß und Oberflächenintegrität ermöglichen eine detaillierte Analyse und Korrela-tion zwischen mikrostrukturellen Eigenschaften und Zerspanbarkeit.
T2 - DVS Congress 2023
CY - Essen, Germany
DA - 11.09.2023
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
KW - Zerspankräfte
PY - 2023
SP - 742
EP - 747
AN - OPUS4-59210
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Müller, Thomas
A1 - Treutler, Kai
A1 - Wesling, Volker
T1 - Legierungsmodifikation und Einsatz hybrider Fräsprozesse zur Optimierung der Zerspanungssituation Ni-basierter Verschleißschutzauftragschweißungen mit definierten Oberflächen
N2 - Die Bestrebungen zur Verringerung der CO2-Emissionen erfordern hochbelastbare und effiziente Komponenten aus Stahl in der Anlagen-, Verfahrens- und Kraftwerkstechnik. Hierfür sind in zunehmendem Maße auf den Anwendungsfall und Stahlwerkstoff abgestimmte Verschleißschutzschich-ten und definierte, zerspante Oberflächen notwendig. Die hohen Härten dieser Schichten und der Einsatz konventioneller Co-basierter Verschleißwerkstoffe führen oftmals zu unwirtschaftlichen Bauteilen, gerade aufgrund hohen Werkzeugverschleißes bei der Zerspanung mit geometrisch bestimmter Schneide. Er-kenntnisse über den Einsatz Ni-basierter Verschleißwerkstoffe und die Optimierung der Zerspanbarkeit mittels Legierungsmodifikationen und moderner hybrider Fräsprozesse ohne Verschlechterung der Ver-schleißschutzeigenschaften sind deshalb für die Anwender und Verarbeiter zur wirtschaftlichen Fertigung hochbelasteter Stahlbauteile wesentlich. Der vorliegende Beitrag stellt die Untersuchungsmethodik eines aktuell laufenden Vorhabens der TU Clausthal und BAM, Berlin, vor. Fokus liegt hierbei auf den hochin-strumentierten Fräsexperimenten, die eine reproduzierbare Analyse und Korrelation zwischen den mik-rostrukturellen Eigenschaften der auftraggeschweißten Legierungen, dem Zerspanprozess und der Zer-spanbarkeit, insbesondere der resultierenden Oberflächenintegrität, ermöglichen sollen.
T2 - Tagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
KW - Ultraschallunterstütztes Fräsen
KW - Zerspankräfte
PY - 2022
SP - 368
EP - 374
AN - OPUS4-59211
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Residual stress formation in DED-arc manufactured high strength steel components
N2 - Additive manufacturing (AM) processes enable the efficient production of advanced constructions. New developments in topology optimization are leading to weight-optimized designs of increasing complexity. Direct energy deposition processes (DED) such as wire and arc-based additive manufacturing are an important method of additive manufacturing. The wire filler metals enable a wide range of materials, while the arc process provides a high deposition rate compared to laser and powder-based processes. Combined with the use of high-strength steels, the thickness of walls or components can be significantly reduced in the context of lightweight construction, which results in significant savings in energy, costs, time and resources. Suitable high-strength steel filler metals are commercially available for DED-arc AM processes. However, guidelines and quantitative knowledge about welding stresses and cold cracking issues during component production and service are lacking. This limits the industrial application considerably. In a joint project of BAM and Chemnitz University of Technology, the main influences and complex interactions of material, production process, design and processing steps on the residual stress level are investigated. The aim is to develop processing recommendations and a cold cracking test for economical processing and stress-related design of high-strength steels with DED-arc. This study focuses on residual stress analysis by neutron diffraction (ND) and X-ray diffraction (XRD) on defined test specimens. The ND analysis were performed at the Paul Scherrer Institute- Villigen, Switzerland (PSI) and the XRD analysis at BAM. The study shows a quantitative and qualitative comparison of the residual stress magnitudes and distribution between the component bulk (ND) and surface (XRD) analyses. The ND analysis reveals that in DED-arc AM walls the residual stresses dominate in the direction of welding and are negligibly small in each case transverse to the direction of welding. The topology of the analyzed residual stresses shows almost identical residual stress maps compared to XRD. In addition, the residual stresses are significantly influenced by the solid phase transformation of the material due to low cooling times and less post heat treatment cycles of following AM layers in the area of the top layer.
T2 - 76th IIW Annual Assembly and International Conference on Welding and Joining
CY - Singapore
DA - 16.07.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
PY - 2023
AN - OPUS4-59233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
T1 - Einfluss trennender Fertigungsschritte auf die Eigenspannungen in additiv gefertigten Bauteilen aus hochfestem Stahl
N2 - Additive Fertigungsverfahren wie das Wire Arc Additive Manufacturing (WAAM) ermöglichen die effiziente Fertigung von gewichtsoptimierten endkonturnahen Strukturen in modernen Stahlkonstruktionen. Ihre Effizienz kann weiter durch die Verwendung von hochfesten Stählen gesteigert werden. Dies erlaubt eine signifikante Einsparung von Kosten, Zeit und Ressourcen. Entsprechende Schweißzusatzwerkstoffe für Lichtbogenschweißverfahren sind kommerziell verfügbar. Fehlende Richtlinien und fehlende quantitative Kenntnisse über die schweißtechnische Beanspruchung während der Fertigung und im Betrieb limitieren den industriellen Einsatz stark. Daher werden in einem aktuellen Vorhaben (IGF-Nr. 21162 BG) der BAM und TU Chemnitz die wesentlichen Einflüsse und komplexen Interaktionen durch Werkstoff, Fertigungsprozess, Konstruktion und trennende Fertigungsschritte auf den Beanspruchungszustand untersucht. Der vorliegende Beitrag fokussiert hierfür die Auswirkungen trennender Fertigungsschritte auf Verzug und Eigenspannungen definierter WAAM-Prüfkörper. Die Eigenspannungsanalyse erfolgt mittels Röntgenbeugung. Die große Anzahl an Ergebnissen von zuvor untersuchten Referenzproben, die mit einem speziellen WAAM-Massivdraht (Streckgrenze >820 MPa) bei unterschiedlicher Wärmeführung und Geometrie vollautomatisiert geschweißt wurden, lässt eine Korrelation der Messdaten zu. Hierzu erfolgt die Analyse des Ausgangszustandes und abschließend des Zustandes nach trennender Bearbeitung, welche begleitend mittels digitaler Bildkorrelation hinsichtlich des Verzuges untersucht wurden. So ist zu beobachten, dass die Geometrie deutlichen Einfluss auf Relaxation und Umlagerung der Eigenspannungen hat und damit die Risssicherheit positiv beeinflussen kann.
T2 - 23. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
DA - 29.03.2023
KW - Additive Fertigung
KW - Hochfester Stahl
KW - Eigenspannungen
KW - Residual stress
PY - 2023
AN - OPUS4-59231
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Ultraschallunterstütztes Fräsen zur Reduzierung der Belastung auf Werkzeug und Bauteiloberfläche von Eisenaluminid-Bauteilen
N2 - Auf der Grundlage einer speziell entwickelten Werkzeugtechnologie sowie Prozessführung können die Belastungen auf das Werkzeug und die Bauteiloberfläche bei der frästechnischen Bearbeitung von Bauteilen aus dem innovativen jedoch schwer zerspanbaren Eisenaluminid deutlich reduziert werden. Die Messung der Prozesskräfte sowie der thermischen Belastung der Werkzeugschneide ermöglicht die Identifikation geeigneter Zerspanungsparameter hinsichtlich einer maximalen Werkzeuglebensdauer. Die Verwendung des ultraschallunterstützten Fräsens (USAM) besitzt vorteilhafte Einflüsse auf den Zerspanprozess, insbesondere hinsichtlich einer homogenen Bauteiloberfläche. Im Rahmen von Standzeitversuchen erfolgt durch USAM ein gleichmäßiger und im Vergleich zum konventionellen Fräsen (CM) deutlich reduzierter Werkzeugverschleiß. Mit wachsendem Zerspanvolumen verstärkt sich der positive Effekt von USAM und äußert sich in einer deutlichen Reduzierung der Rauheit und Defektdichte auf der Bauteiloberfläche.
T2 - 5. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 23.02.2023
KW - Eisenaluminid
KW - Ultraschallunterstütztes Fräsen
KW - Werkzeugverschleiß
KW - Oberflächenintegrität
PY - 2023
AN - OPUS4-59223
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Alloy modification and use of hybrid milling processes to optimize the machining situation of Ni-based wear protection claddings with defined surfaces
N2 - The goals of reducing CO2 emissions are closely linked to the development of highly efficient and economical steel components in plant, process and power plant engineering, which require wear protection coatings tailored to the application and steel material for high combined corrosive, tribological, thermal and mechanical stresses. In addition to increasing demands to replace conventional cobalt alloys with nickel alloys due to the price and supply risk, there is a growing demand in the industry for defined surfaces of high quality or functional surfaces for the protective coatings. Milling required for components with complex geometries is often not economically feasible, especially for SMEs, due to high tool wear, but is urgently required for many applications.
A joint project between BAM and ISAF at Clausthal University of Technology (Fosta P1550/IGF 21959 N) is therefore investigating how more favorable machinability can be achieved by means of alloy modifications to the filler metals for nickel-based plasma deposition-welded wear protection coatings and by using innovative ultrasound-assisted milling processes, without reducing the wear protection potential.
This article examines the influence of the microstructure and precipitation morphology set by means of alloy modification on machining. This is carried out using wear resistant cladding typically used for screw machines to replace corresponding CoCr alloys (Stellite), a NiCrMoSiFeB alloy (trade name: Colmonoy 56 PTA). A detailed analysis and correlation between the microstructural properties and the machinability is possible through metallurgical investigations and in-situ measurement of process forces and temperatures occurring at the tool cutting edge during the milling process as well as the subsequent investigation of tool wear and surface integrity. The changes in the microstructure achieved by adding small amounts of modifying elements (< 1 m%) lead to significant differences in machinability. The cutting forces and the resulting tool wear are thus positively influenced, whereby longer tool life and higher surface integrities can be achieved. The knowledge gained allows for instructions and recommendations for standards and processing guidelines, which should enable the safe and economical production of highly stressed steel components with non-critical, cost-reduced materials, especially for SMEs.
T2 - MPA Seminar Stuttgart
CY - Stuttgart, Germany
DA - 08.10.2024
KW - Ultrasonic assisted milling
KW - Surface integrity
PY - 2024
AN - OPUS4-61972
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - Optimizing residual stresses in additively manufactured high-performance materials
N2 - The integration of modern high-performance materials in combination with additive manufacturing (AM) has revolutionized the approach to lightweight construction across diverse applications. This study explores the synergy between these materials and additive manufacturing (AM), focusing on their unique properties to engineer resource-efficient structures. Despite these advancements, machining these hard-to-cut materials such as iron-aluminide for safety-critical components remains challenging due to increased tool wear and compromised surface integrity. This research focuses on overcoming these challenges through the application of ultrasonic-assisted milling (USAM), a hybrid machining process exhibiting significant potential. By incorporating ultrasonic oscillations along the milling tool axis, USAM minimizes tool and component surface loads, enhancing tool life and producing defect-free, homogeneous surfaces with reduced roughness parameters. This investigation centers on the influence of ultrasonic-assisted milling on residual material stresses, crucial for component performance under load. In contrast to conventional milling generating tensile stresses, USAM induces advantageous compressive residual stresses, potentially enhancing the component's crack resistance. The study employs experimental variations in ultrasonic amplitude during the machining process to identify optimal parameters for achieving maximum compressive stresses. In addition, the depth profile of these residual stresses on the surface is investigated, which provides more detailed insights into their distribution and possible effects. This research not only contributes to the evolving environment of innovative manufacturing technologies, but also places particular focus on the central role of residual stresses in the performance and reliability of safety-critical AM components. The results not only contribute to a better understanding of ultrasonic-assisted milling, but also provide crucial guidance for the design of components that can withstand the challenges of real-world applications.
T2 - European Conference on Surface Integrity 11
CY - Prague, Czech Republic
DA - 03.06.2024
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - High-performance materials
KW - Surface integrity
KW - Residual stresses depth profile
PY - 2024
AN - OPUS4-62026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Scharf-Wildenhain, Ronny
A1 - Hälsig, Andre
A1 - Kromm, Arne
A1 - Hensel, J.
T1 - Fertigungsbedingte Beanspruchungen und Kaltrisssicherheit in generativ gefertigten Bauteilen aus hochfesten Feinkornbaustählen
N2 - Additive Fertigungsverfahren wie das Direct Energy Deposition-Arc (DED-Arc) oder Wire Arc Additive Manufacturing (WAAM) ermöglichen die effiziente Herstellung gewichtsoptimierter, endkonturnaher Bauteile im modernen Stahlbau. Steigerungen der Effizienz können durch den Einsatz hochfester Stähle erreicht werden, insbesondere durch Verringerung von Wandstärken und Bauteilgewicht sowie signifikante Einsparung von Kosten, Zeit und Ressourcen. DED-Arc Schweißzusatzwerkstoffe sind bereits auf dem Markt verfügbar, allerdings fehlen Richtlinien und quantitative Kenntnisse über die schweißbedingte Beanspruchung während der Fertigung und im Betrieb, welche den industriellen Einsatz stark limitieren. In einem gemeinsamen Projekt der BAM und der Technischen Universität Chemnitz wurden die wesentlichen Einflüsse und komplexen Wechselwirkungen von Werkstoff, Fertigungsverfahren, Konstruktion und Bearbeitungsschritten auf die Eigenspannungen untersucht. Ziel war es, den stahlverarbeitenden Anwendern, insbesondere KMU, eine risssichere und beanspruchungsgerechte Herstellung und Modifizierung von Bauteilen und Halbzeugen aus hochfesten Feinkornbaustahl unter Verwendung MSG-basierter generativer Verfahren zu ermöglichen.
T2 - DVS Innovationstage 2024
CY - Düsseldorf, Germany
DA - 10.04.2024
KW - Feinkornbaustähle
KW - Additive Fertigung
KW - Kaltrisssicherheit
KW - Direct Energy Deposition-Arc (DED-Arc), Wire Arc Additive Manufacturing (WAAM)
PY - 2024
AN - OPUS4-61934
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gräbner, Maraike
T1 - The evaluation of the impact of alloy modification on the wear protection coatings made of Ni- and Co-based materials and the examination of surface machinability through the ultrasonic milling process
N2 - The development of technologies for climate-neutral energy generation is an important contribution to the reduction of greenhouse gases, whereby the efficient use of material systems is a key factor. Wear-resistant coatings are required for highly efficient and economical steel components in plant, process and power plant engineering to withstand the high corrosive, tribological, thermal and mechanical stresses. Co alloys are utilized as wear protection coatings for steel components that are customized to the specific application. The research area of interest is the substitutability of Co alloys with Ni-based wear protection systems. This research endeavour considers the price and supply uncertainties as well as the escalating demands on corrosive load-bearing capacity at elevated temperatures.
The wear-resistant alloys NiMoCrSi (Colmonoy C56) and CoMnCrSi (Tribaloy T400) have been modified through various alloying additions and subsequently applied to a carbon-manganese steel S355 using the Plasma Arc Transferred Arc (PTA) welding process. The influence of the alloying additions on the microstructure as well as on the formation of the hard phases of the build-up welds is compared. The inclusion of the alloying element Nb, for instance, results in the formation of a more refined hard phase and reduces the machining force required for the C56 and T400. The incorporation of Al results in an enhancement of the cutting forces for the C56, as the hard phases exhibit more needle-like structures. Al reduces the cutting forces of the T400. The wear potential of the modified build-up welds of the C56 and T400 is also being examined In the industrial sector, there is a growing demand for functional surfaces of superior quality. Therefore, it is imperative to ensure the machinability of the wear protection layers to achieve clearly defined contours. The machinability of the build-up welds is investigated using ultrasonic milling. The optimization of the demanding machining conditions through alloy modifications of the Co- and Ni-based alloys without impairing the wear protection potential and using the ultrasonic-assisted milling process is a joint project of BAM and ISAF at Clausthal University of Technology (Fosta P1550/IGF 21959 N).
T2 - ICMCTF
CY - San Diego, CA, USA
DA - 19.05.2024
KW - Ultrasonic assisted milling
KW - Surface integrity
PY - 2024
AN - OPUS4-62358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Treutler, Kai
T1 - Additive Manufacturing of Iron Aluminides: Microstructure, Machinability, and Surface Integrity
N2 - The increasing global focus on energy and resource efficiency has stimulated a growing interest in additive manufacturing. AM offers economic advantages and enables an efficient use of materials. However, AM components often require subsequent mechanical post-processing, such as machining (e.g. milling), to achieve the final contours or surfaces. This is a particular challenge due to the heterogeneous and anisotropic nature of AM structures, which affect machining and the resulting component properties. High-performance materials such as iron aluminide represent a promising alternative to conventional high-temperature materials with a significant economic advantage. However, the strength and hardness properties, which are advantageous for applications in highly stressed lightweight components, pose a challenge for economical machining in addition to the AM microstructure properties. The difficult-to-cut material causes accelerated tool wear and insufficient surface quality. This study shows that crack-free additive manufacturing of the three-component system of iron-nickel-aluminum is possible and advantages in terms of machinability compared to FeAl-AM components are achieved. The more homogeneous microstructure leads to a reduction in cutting forces, with positive effects on the machinability and optimized surface integrity. Ultrasonic assisted milling (USAM) offers great potential to address the major challenges posed by difficult-to-cut materials and additively manufactured weld structures. Therefore, this study focuses on assessing the transferability of previous positive results by USAM to the selected iron aluminide alloys. The machinability of the aluminides is analyzed by varying significant influencing variables in finish milling experiments and evaluated in terms of the loads on the tool and the resulting surface integrity.
T2 - Intermediate Meeting of IIW
CY - Online meeting
DA - 13.03.2024
KW - Additive manufacturing
KW - Surface-integrity
KW - Iron-aluminide
KW - Ultrasonic-assisted milling
KW - Difficult-to-cut
KW - Tool wear
PY - 2024
AN - OPUS4-62294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
A1 - Thomas, Maximilian
A1 - Liepold, Philipp
A1 - Kannengießer, Thomas
A1 - Schröpfer, Dirk
T1 - Einfluss der Schweiß- und Prüfparameter bei der Heißrissbewertung hochfester Schweißzusatzwerkstoffe
N2 - Die Heißrissneigung beim Schweißen kann mittels einer ganzen Reihe von Prüfverfahren ermittelt werden. Eine etablierte Methode ist die sogenannte Varestraint-Prüfung, welche auch an der Bundesanstalt für Materialforschung und -prüfung (BAM) als modifizierter Varestraint/Transvarestraint-Test (MVT) zum Einsatz kommt. Die Ergebnisse von Varestraint-Prüfungen hängen jedoch stets in unter-schiedlichem Maße von der individuellen Prüfmaschinenauslegung und den verwendeten Prüfparametern ab. Dies kann zu einer uneinheitlichen Bewertung des Rissverhaltens führen, wenn die Risslänge konventionell als Kriterium für die Rissneigung herangezogen wird. Scheinbare Abhängigkeiten von Prozessparametern erschweren dann die Interpretation der Ergebnisse. Eine neuartige Bewertungsmethodik entkoppelt den Maschineneinfluss vom Materialverhalten und verwendet die Dehnrate als Risskriterium.
T2 - 5. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 23.02.2023
KW - Heißrisse
KW - Varestraint-Test
PY - 2023
SN - 978-3-8440-9105-2
SN - 2364-0804
VL - 12
SP - 357
EP - 365
PB - Shaker
CY - Düren
AN - OPUS4-57993
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Treutler, K.
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die additive Fertigung (AM) durch schweißtechnische Verfahren eröffnet vielfach ökonomische Vorteile für eine ressourceneffiziente Bauteilherstellung. Gerade hinsichtlich der Homogenität und Anisotropie der resultierenden Schweißgefüge und den damit verbundenen Eigenschaften gibt es noch offene Fragestellungen. Die Einstellung der finalen Bauteilgeometrie und Oberflächengüte erfordert den komplementären Einsatz abtragender Fertigungsschritte. Hochleistungslegierungen auf der Basis von Nickel oder Kobalt sind aufgrund ihrer niedrigen Wärmeleitfähigkeit verbunden mit hoher Festigkeit und Zähigkeit schwer spanbar. Eine gezielte Gefügebeeinflussung mittels Modifikation der AM-Schweißzusatzwerkstoffe und der Einsatz des ultraschallunterstützten Fräsens (US) bietet das Potential insgesamt die Zerspanungssituation zu verbessern. Dieser Lösungsansatz unter Gewährleistung des Erhalts der geforderten Werkstoff- bzw. Bauteileigenschaften ist Untersuchungsgegenstand eines Gemeinschaftsvorhabens (IGF-Nr. 20.979 N/DVS-Nr. 1.3211) der BAM und TU Clausthal/ISAF. Der vorliegende Beitrag stellt Ergebnisse für die beiden untersuchten FeNi- und CoCr-Legierungen sowie wesentliche Zusammenhänge zwischen Legierungsmodifikation, entstehender Gefügemorphologie und Zerspanungseigenschaften der mittels MAG additiv gefertigter Proben vor. Das größte Potential für die Modifikation zeigten Zr und Hf. Die Zulegierung in das Schweißgut erfolgte durch Beschichtung von Massivdrähten sowie durch Herstellung von Fülldrähten.
T2 - DVS Congress - GST
CY - Essen, Germany
DA - 11.09.2023
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Schwer spanbar
KW - Metallschutzgasschweißen
PY - 2023
AN - OPUS4-58379
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - On the limitations of small cubes as test coupons for process parameter optimization in laser powder bed fusion of metals
N2 - The capability to produce complexly and individually shaped metallic parts is one of the main advantages of the laser powder bed fusion (PBF LB/M) process. Development of material and machine specific process parameters is commonly based on results acquired from small cubic test coupons of about 10 mm edge length. Such cubes are usually used to conduct an optimization of process parameters to produce dense material. The parameters are then taken as the basis for the manufacturing of real part geometries. However, complex geometries go along with complex thermal histories during the manufacturing process, which can significantly differ from thermal conditions prevalent during the production of simply shaped test coupons. This may lead to unexpected and unpredicted local inhomogeneities of the microstructure and defect distribution in the final part and it is a root cause of reservations against the use of additive manufacturing for the production of safety relevant parts. In this study, the influence of changing thermal conditions on the resulting melt pool depth of 316L stainless steel specimens is demonstrated. A variation of thermo-graphically measured intrinsic preheating temperatures was triggered by an alteration of inter layer times and a variation of cross section areas of specimens for three distinct sets of process parameters. Correlations between the preheating temperature, the melt pool depth, and occurring defects were analyzed. The limited expressiveness of the results of small density cubes is revealed throughout the systematic investigation. Finally, a clear recommendation to consider thermal conditions in future process parameter optimizations is given.
T2 - Icaleo 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Additive manufacturing
KW - Heat accumulation
KW - Thermal history
KW - In situ monitoring
KW - Representative specimens
KW - Thermography
PY - 2023
AN - OPUS4-58656
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - On critical shifts of the process window due to heat accumulation in laser powder bed fusion
N2 - Safety-critical applications of products manufactured by laser powder bed fusion (PBF-LB/M) are still limited to date. This is mainly due to a lack of knowledge regarding the complex relationship between process, structure, and resulting properties. The assurance of homogeneity of the microstructure and homogeneity of the occurrence and distribution of defects within complexly shaped geometries is still challenging. Unexpected and unpredicted local inhomogeneities may cause catastrophic failures. The identification of material specific and machine specific process parameter windows for production of fully dense simple laboratory specimens is state of the art. However, the incorporation of changing thermal conditions that a complexly shaped component can be faced with during the manufacturing process is often neglected at the stage of a process window determination. This study demonstrates the tremendous effect of changing part temperatures on the defect occurrence for the broadly used stainless steel alloy AISI 316L. Process intrinsic variations of the surface temperature are caused by heat accumulation which was measured by use of a temperature adjusted mid-wavelength infrared (MWIR) camera. Heat accumulation was triggered by simple yet effective temporal and geometrical restrictions of heat dissipation. This was realized by a variation of inter layer times and reduced cross section areas of the specimens. Differences in surface temperature of up to 800 K were measured. A severe development of keyhole porosity resulted from these distinct intrinsic preheating temperatures, revealing a shift of the process window towards unstable melting conditions. The presented results may serve as a warning to not solely rely on process parameter optimization without considering the actual process conditions a real component is faced with during the manufacturing process. Additionally, it motivates the development of representative test specimens.
T2 - The 76th IIW annual assembly and international conference on welding and joining
CY - Singapore
DA - 16.07.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Laboratory specimens
KW - Process parameter optimization
KW - Heat accumulation
KW - Keyhole porosity
KW - Infrared thermography
PY - 2023
AN - OPUS4-58023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kaiser, Sebastian
T1 - Repair welding of pressurized in-service hydrogen pipelines: A review on current challenges and strategies
N2 - As energy carrier of the future, green hydrogen can make a decisive contribution to a sustainable energy supply. In Europe concrete plans for a hydrogen pipeline grid already exist, as the so called “European Hydrogen backbone”. As building a completely new pipeline grid is economically not justifiable, a dual-way strategy of repurposing natural gas (NG) pipelines and newly built pipelines is intended. Long distance pipeline grids require regular maintenance and repairs. In that conection, for natural gas (NG) pipelines in-service welding is state of the art. Concepts such as hot-tapping (drilling into pressurized pipelines) and “stoppling” (sealing off pipeline sections after installing bypasses or pressure relieves) allow the repair of damaged pipeline sections or the installation of new branches without shutting the pipeline down. The EIGA 121/14 guideline already pointed out in 2014 that “a hydrogen hot-tap shall not be considered a routine procedure”. This shows that the determination of the transferability of these repair concepts to hydrogen pipelines is of utmost importance. Due to the degrading effects of hydrogen on mechanical proper-ties, commonly referred to as “hydrogen embrittlement” it is necessary to understand and investigate the occurring effects. In the special case of repair welding on in-service hydrogen pipelines an increased hydro-gen uptake due to a large heat input and microstructural changes in the material needs to be considered. For this reason, this paper gives an overview on existing weld repair concepts and its risks and limitations in terms of hydrogen absorption and possible embrittlement effects when transferred to hydrogen pipelines. The complexity lies in a large variety of materials (low alloyed steels), pipeline diameters and corresponding welded joints. The material compatibility of materials in used (repurposed NG-pipelines) and new condition must be investigated. Particularly for repurposed/used pipelines the effect of a pre-matured/corroded inner surface and sometimes insufficient documentation of the material “history” needs to be considered. An overview on ongoing and completed R&D-projects with respect to repair concepts for hydrogen pipelines and hydrogen effects on pipeline materials is given.
T2 - 77th IIW Annual Assembly and International Conference, Meeting of Commission XI "Pressure Vessels and Piping"
CY - Ixia, Rhodes, Greece
DA - 07.07.2024
KW - Hydrogen
KW - Repair welding
KW - Pipelines
KW - Study
PY - 2024
AN - OPUS4-60673
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die additive Fertigung mittels Schweißverfahren bietet große ökonomische Vorteile für eine ressourceneffiziente Bauteilherstellung. Offene Fragen bezüglich Homogenität, Anisotropie der Schweißgefüge und den damit verbundenen Bauteileigenschaften stehen einer wirtschaftlichen Verarbeitung oftmals im Wege. Finale Bauteilgeometrie und Oberflächengüte erfordern meist komplementäre subtraktive Fertigungsschritte. Werkstoffe für hochbelastbare Komponenten sind oftmals schwer spanbar. In einem Vorhaben der BAM und des ISAF wurde untersucht, wie die Modifikation der AM-Schweißzusätze und das ultraschallunterstützte Fräsen (US) die Zerspanungssituation verbessern. Der vorliegende Artikel stellt wesentliche Zusammenhänge zwischen Legierung, Gefüge und Zerspanung zweier schwer spanbarer Hochleistungslegierungen (FeNi und CoCr) dar. Großes Potenzial zeigte neben dem US die Modifikation mit Zr und Hf bei Zulegierung in das Schweißgut mittels Beschichtung von Massivdrähten bzw. Herstellung von Fülldrähten.
T2 - Innovationstag 2024
CY - Düsseldorf, Germany
DA - 10.04.2024
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Additive Fertigung
KW - Oberflächenintegrität
PY - 2024
AN - OPUS4-59958
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Ralf
T1 - GlasDigital: Data-driven workflow for accelerated glass development
N2 - lasses stand out by their wide and continuously tunable chemical composition and large variety of unique shaping techniques making them a key component of modern high technologies. Glass development, however, is still often too cost-, time- and energy-intensive. The use of robotic melting systems embedded in an ontology-based digital environment is intended to overcome these problems in future. As part of the German research initiative MaterialDigital, the joint project GlasDigital takes first steps in this direction. The project consortium involves the Fraunhofer ISC in Würzburg, the Friedrich Schiller University Jena (OSIM), the Clausthal University of Technology (INW), and the Federal Institute for Materials Research and Testing (BAM, Division Glasses) and aims to combine all main basic components required for accelerated data driven glass development. For this purpose, a robotic high throughput glass melting system is equipped with novel inline sensors for process monitoring, machine learning (ML)-based, adaptive algorithms for process monitoring and optimization, novel tools for high throughput glass analysis and ML-based algorithms for glass design, including software tools for data mining as well as property and process modelling. The talk gives an overview how all these tools are interconnected and illustrates their usability with some examples.
T2 - HVG-DGG Fachausschuss I
CY - Jena, Germany
DA - 03.11.2023
KW - Glass
KW - Robotic melting
KW - Ontologie
KW - Simulation
KW - Workflow
KW - Data Space
PY - 2023
AN - OPUS4-60383
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Ya‐Fan
A1 - Arendt, Felix
A1 - Bornhöft, Hansjörg
A1 - de Camargo, Andréa S. S.
A1 - Deubener, Joachim
A1 - Diegeler, Andreas
A1 - Gogula, Shravya
A1 - Contreras Jaimes, Altair T.
A1 - Kempf, Sebastian
A1 - Kilo, Martin
A1 - Limbach, René
A1 - Müller, Ralf
A1 - Niebergall, Rick
A1 - Pan, Zhiwen
A1 - Puppe, Frank
A1 - Reinsch, Stefan
A1 - Schottner, Gerhard
A1 - Stier, Simon
A1 - Waurischk, Tina
A1 - Wondraczek, Lothar
A1 - Sierka, Marek
T1 - Ontology‐Based Digital Infrastructure for Data‐Driven Glass Development
N2 - The development of new glasses is often hampered by inefficient trial‐and‐error approaches. The traditional glass manufacturing process is not only time‐consuming, but also difficult to reproduce with inevitable variations in process parameters. These challenges are addressed by implementing an ontology‐based digital infrastructure coupled with a robotic melting system. This system facilitates high‐throughput glass synthesis and ensures the collection of consistent process data. In addition, the digital infrastructure includes machine learning models for predicting glass properties and a tool for extracting patent information. Current glass databases have significant gaps in the relationships between compositions, process parameters, and properties due to inconsistent studies and nonconforming units. In addition, process parameters are often omitted, and even original literature references provide limited information. By continuously expanding the database with consistent, high‐quality data, it is aimed to fill these gaps and accelerate the glass development process.
KW - Digitalisation
KW - Data-driven glass development
KW - Ontology
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625844
DO - https://doi.org/10.1002/adem.202401560
SN - 1527-2648
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-62584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Fast crack healing in glass-matrix composites with rigid filler percolation frameworks
N2 - To ensure the durability of solid oxide fuel cell sealants, the understanding of the microstructural influence on viscous crack healing is essential. To this end, the effect of microstructure with respect to the spatial distribution of filler particles on viscous crack healing was studied with confocal laser scanning microscopy in glass-matrix composites (GMCs) made by mix-milling and sintering of sodalime magnesium silicate glass and Φ ≈ 6 vol% ZrO2 chemically inert rigid filler particles. This way, no change in Φ occurred during the crack healing treatments studied on Vickers indentation-induced radial cracks in polished GMC surfaces.
Different microstructures were mimicked using different ZrO2 particle sizes for mix-milling. Unlike coarse ZrO2 particles, similar in size to the glass particle, fine ZrO2 particles, much smaller than the glass particles, form a rigid percolation framework (RPF) of ZrO2 filler particles around the former glass particles or glass particle agglomerates. For this RPF microstructure, crack healing was observed more readily as crack healing retardation phenomena like large-scale crack widening and crack tip rounding were strongly reduced, whereas narrow cracks could still heal locally within the glassy regions.
KW - Crack healing
KW - Glass matrix composite
KW - Rigid percolation frameworks
KW - Vickers indentation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625921
DO - https://doi.org/10.1111/jace.20386
SN - 0002-7820
SP - 1
EP - 10
PB - Wiley
AN - OPUS4-62592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - In situ Untersuchung der Phasenverteilung und der Schmelzbaderstarrung von Duplexstählen mittels laserinduzierter Plasmaspektroskopie (LIPS)
N2 - Schweißprozesse von nichtrostenden Duplexstählen verursachen aufgrund hoher Abkühlungsraten und Änderungen der chemischen Zusammensetzung ein unausgewogenes Austenit (γ)/Ferrit (δ)-Verhältnis. Das verursacht eine Degradation der mechanischen Eigenschaften und der Korrosionsbeständigkeit. Die In-situ-Überwachung des Schweißbades soll mit Hilfe der laserinduzierten Plasmaspektroskopie (LIPS) realisiert werden. Ein großer Vorteil dieser Technik ist die hochgenaue zeit- und ortsaufgelöste Messung der chemischen Zusammensetzung während des Schweißens. Bisherige Untersuchungen haben ergeben, dass die LIBS-Methode geeignet ist, chemische Elemente während des Schweißens zu detektieren und eine Verteilung ausgewählter Elemente aufzuzeigen. Chemische Zusammensetzungen können mit vorab erstellten Kalibrierkurven dargestellt weerden.
T2 - BMDK der Universität Magdeburg
CY - Online Meeting
DA - 17.06.2021
KW - LIBS
KW - In situ
KW - Duplex stainless steel
KW - TIG welding
PY - 2021
AN - OPUS4-52823
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Effects of inter layer time and build height on resulting properties of 316L stainless steel processed by laser powder bed fusion
N2 - Das pulverbettbasierte selektive Laserstrahlschmelzen (engl. laser powder bed fusion, L-PBF) ist die am weitesten verbreitete additive Fertigungstechnologie für die Herstellung metallischer Komponenten. Unter der Vielzahl an Einflussfaktoren auf die Qualität und die mechanischen Eigenschaften von L PBF-Bauteilen hat die Zwischenlagenzeit (engl. inter layer time, ILT) bisher kaum Beachtung in der wissenschaftlichen Literatur gefunden, obwohl sie je nach Bauraumausnutzungsgrad stark variieren kann. In diesem Vortrag werden Ergebnisse einer Studie präsentiert, die den Einfluss der ILT in Kombination mit der Bauteilhöhe und unter Berücksichtigung verschiedener Volumenenergiedichten am Beispiel der austenitischen Stahllegierung AISI 316L untersucht. Die Fertigungsprozesse wurden in situ mittels Thermographiekamera überwacht, sodass Informationen über das Abkühlverhalten der Bauteile während des Prozesses gewonnen werden konnten. Es wurden signifikante Effekte der ILT und der Bauteilhöhe auf Wärmeakkumulation, Mikrostruktur, Schmelzbadgeometrie und Härte festgestellt. Ferner konnte ein Anstieg von Defektdichten bei einem gegenseitigen Wechselspiel aus Bauteilhöhe und ILT aufgezeigt werden. Die Zwischenlagenzeit wurde somit als kritischer Faktor für die L-PBF-Fertigung von Realbauteilen identifiziert.
T2 - Workshop In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys
CY - Online meeting
DA - 19.04.2021
KW - Infrared thermography
KW - Laser Powder Bed Fusion (L-PBF)
KW - Selective Laser Melting (SLM)
KW - Additive Manufacturing (AM)
KW - Process monitoring
PY - 2021
AN - OPUS4-52699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Tales from Within: Residual Stress and Void Formation in LPBF 316L
N2 - An unusual microstructure, inherent residual stresses and void formation are the three key aspects to control when assessing metallic parts made by LPBF. This talk explains an experiment to unravel the interlinked influence of the two mechanisms for the formation of residual stresses in LPBF: the temperature gradient mechanism and constricted solidification shrinkage. The impact of each mechanism on the shape and magnitudes of the residual stress distribution is described. Combined results from neutron diffraction, X-ray diffraction, computed tomography and in-situ thermography are presented.
Also, influence of scan strategies as well as surface roughness of subjacent layers on void formation is shown. Results from computed tomography and in-situ thermography of a specimen dedicated to study the interaction of the melt pool with layers of powder underneath the currently illuminated surface are presented.
T2 - 2nd Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online meeting
DA - 19.04.2021
KW - Neutron diffraction
KW - Laser powder bed fusion
KW - In-situ thermography
KW - Computed tomography
KW - X-ray diffraction
KW - Residual stress
KW - Pore formation
KW - AISI 316L
PY - 2021
AN - OPUS4-52819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
T1 - Spatially resolved EDS, XRF and LIBS measurements of the chemical composition of duplex stainless steel welds: A comparison of methods
N2 - Duplex stainless steels (DSS) are used in all industries where corrosion problems play a major role. Examples include the chemical industry, the food industry and shipping industries. DSS have a balanced phase ratio of ferrite (α) and austenite (γ). Unlike single-phase stainless steels, DSS combine the advantages of these and can therefore fit many industry requirements, such as weight saving or high mechanical strength. When these steels are welded, alloying elements can burn off and condense as thin layers on cold surface regions. This loss of chemical elements can lead to changes in the microstructure. With the help of Laser-Induced Breakdown Spectroscopy (LIBS), chemical element distributions were visualized. The results were compared with those of conventional measurement methods, such as energy dispersive X-ray analysis (EDS) and X-ray fluorescence analysis (XRF), and the results from LIBS could be validated. LIBS is suitable as a fast, straightforward measurement method for producing line scans along the weld seam and provides spatially resolved information on accumulation phenomena of burned off alloying elements. LIBS is very well suited for the detection of sub-surface elements due to the exclusively superficial ablation of the material. In addition, the measurement method has been calibrated so that quantitative statements about element concentrations can also be made.
T2 - EMSLIBS 2021
CY - Online Meeting
DA - 25.11.2021
KW - LIBS
KW - TIG welding
KW - Duplex stainless steel
KW - XRF
KW - EDS
PY - 2022
DO - https://doi.org/10.1016/j.sab.2022.106439
SN - 0584-8547
VL - 193
SP - 1
EP - 8
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-54837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Untersuchungsmethoden beim Fräsen additiv gefertigter schwer spanbarer Co Cr Legierungen
N2 - Für den Anlagenbau werden hochbelastete Komponenten aus Co-Cr-Legierungen hergestellt. Dabei ist die Zerspanung so herausfordernd, dass additive Fertigungsschritte oft wirtschaftlicher sind. Diese bedingen aber vorwiegende heterogene, anisotrope Gefüge und Eigenschaften und bei nachfolgender Fräsbearbeitung unstetige Zerspankräfte und instabile Spanvorgänge. Hierbei können hybride Zerspanprozesse helfen, hohe Belastungen für Werkzeug und Werkstückoberfläche zu minimieren. Diesbezügliche Charakterisierungen erfordern speziell adaptierte Zerspanungsanalysen.
Anhand eines Anwendungsbeispiels, bei dem eine Modifikation der Ausgangslegierung mit 1 % Hf erfolgte, wird die Wechselwirkung zwischen Gefügemorphologie und Fräsprozess dargestellt, der konventionelle mit einem hybriden ultraschallunterstützten Fräsprozess verglichen und die Charakterisierung des Werkzeugverschleißes anhand zweier verschiedener Fräser betrachtet. Analysen auftretender Prozesskräfte mittels Piezo-Mehrkomponenten-Dynamometer, der Werkzeugoszillation mittels Laser-Vibrometer und zusätzliche In-situ-Temperaturmessungen der Werkzeugschneiden mittels Highspeed-Pyrometer bilden den Kern der neuen Zerspanungsprüftechik.
Die vorgestellten Untersuchungsmethoden bilden die Vorgänge bei der Zerspanung additiv gefertigter Werkstoffe detailliert und reproduzierbar ab. Sowohl Legierungsmodifikation als auch hybride Prozessbedingungen lassen gezielte Einflüsse zur deutlichen Verbesserung der Zerspanungssituation zu.
T2 - Tagung Werkstoffprüfung 2021
CY - Online meeting
DA - 02.12.2021
KW - Legierungsmodifikation
KW - Ultraschallunterstütztes Fräsen
KW - Plasma-Pulver-Auftragschweißen
KW - Additive Fertigung
KW - Co-Cr-Legierung
PY - 2021
AN - OPUS4-54903
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Optimisation of surface residual stresses using hybrid milling processes for additive manufactured Ni alloy components
N2 - Ni alloys are cost intensive materials and generally classified as difficult-to-cut materials. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. Recent studies exhibited that hybrid machining processes, such as ultrasonic-assisted milling (USAM), are suitable for achieving favourable residual stress states at the surface of difficult-to-cut Ni-Cr alloys. In this investigation, wire arc additive manufactured (WAAM) specimens of alloy 36 were finish milled under different milling conditions. In addition to the machined surfaces condition and topology, the surface-near residual stresses were analysed using X-ray diffraction (XRD). Especially for low cutting speeds, significantly improved surface properties, roughness parameters and lower mechanical and microstructural degradations were found for the specimen machined with USAM compared to conventional milling. The improved surface integrity could furthermore be observed by a significant reduction of the tensile residual stresses in the surface boundary area.
T2 - ICRS11, 11th International Conference on Residual Stresses
CY - Nancy, France
DA - 27.03.2022
KW - Surface integrity
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - Ni alloy
KW - Alloy 36
PY - 2022
AN - OPUS4-54904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
T1 - Untersuchungsmethoden beim Fräsen additiv gefertigter schwer spanbarer Kobalt-Chrom-Legierungen
N2 - Für den Anlagenbau werden hochbelastete Komponenten aus Co-Cr-Legierungen hergestellt. Dabei ist die Zerspanung so herausfordernd, dass additive Fertigungsschritte oft wirtschaftlicher sind. Diese bedingen aber vorwiegende heterogene, anisotrope Gefüge und Eigenschaften und bei nachfolgender Fräsbearbeitung unstetige Zerspankräfte und instabile Spanvorgänge. Hierbei können hybride Zerspanprozesse helfen, hohe Belastungen für Werkzeug und Werkstückoberfläche zu minimieren. Diesbezügliche Charakterisierungen erfordern speziell adaptierte Zerspanungsanalysen.
Anhand eines Anwendungsbeispiels, bei dem eine Modifikation der Ausgangslegierung mit 1 % Hf erfolgte, wird die Wechselwirkung zwischen Gefügemorphologie und Fräsprozess dargestellt, der konventionelle mit einem hybriden ultraschallunterstützten Fräsprozess verglichen und die Charakterisierung des Werkzeugverschleißes anhand zweier verschiedener Fräser betrachtet. Analysen auftretender Prozesskräfte mittels Piezo-Mehrkomponenten-Dynamometer, der Werkzeugoszillation mittels Laser-Vibrometer und zusätzliche In-situ-Temperaturmessungen der Werkzeugschneiden mittels Highspeed-Pyrometer bilden den Kern der neuen Zerspanungsprüftechnik.
Die vorgestellten Untersuchungsmethoden bilden die Vorgänge bei der Zerspanung additiv gefertigter Werkstoffe detailliert und reproduzierbar ab. Sowohl Legierungsmodifikation als auch hybride Prozessbedingungen lassen gezielte Einflüsse zur deutlichen Verbesserung der Zerspanungssituation zu.
T2 - Bachelor-, Master-, Doktoranden-Kolloquium
CY - Online meeting
DA - 26.01.2022
KW - Ultraschallunterstütztes Fräsen
KW - Legierungsmodifikation
KW - Additive Fertigung
KW - Werkzeugverschleiß
PY - 2022
AN - OPUS4-54907
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quackatz, Lukas
T1 - Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical concentration by Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - Nichtrostende Duplexstähle (DSS) werden häufig verwendet, insbesondere bei Anwendungen, die eine hohe Festigkeit in Verbindung mit einer hohen Korrosionsbeständigkeit in aggressiven Medien erfordern. Beispiele hierfür sind Kraftwerkskomponenten und maritime Anwendungen. Beim Schweißen dieser Stähle kann es zu lokalen Schwankungen in der chemischen Zusammensetzung kommen. Dies führt zu einer Ferritisierung des Werkstoffs und beeinträchtigt die mechanischen Eigenschaften der Bauteile. In dieser Arbeit wurden Versuche zum Wolfram-Inertgas-Schweißen (WIG) mit DSS durchgeführt. Die Analyse der chemischen Zusammensetzung wurde in situ mit Hilfe der laserinduzierten Plasmaspektroskopie (LIBS) durchgeführt. Ziel der Arbeit ist es, die chemische Zusammensetzung in der Schweißnaht verschiedener DSS quantitativ zu messen und mögliche Einflüsse der Schweißparameter auf die Mikrostruktur des Werkstoffs zu ermitteln. Gemessen wurden die chemischen Konzentrationen der Hauptlegierungselemente Cr, Ni, Mn auf der Oberfläche der Probe während des Schweißprozesses und des Abkühlungsprozesses. Mn und Ni sind Austenitstabilisatoren, deren Gehalt beim Schweißen durch die Verwendung bestimmter hochlegierter Schweißzusatzwerkstoffe zunimmt. Die Spektren wurden alle 1,3 s in einem Abstand von etwa 2 mm aufgezeichnet. Während des Abkühlungsprozesses wurde der Ort der Messung nicht verändert. Die LIBS-Methode eignet sich nachweislich zur quantitativen Darstellung der chemischen Zusammensetzungen während des Schweißvorgangs.
T2 - BMDK der Universität Magdeburg
CY - Magdeburg, Germany
DA - 19.05.2022
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Evaporation
PY - 2022
AN - OPUS4-54865
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Fügetechnik in Wasserstofftechnologien Ein aktueller Überblick
N2 - Der Vortrag gibt einen kurzen Überblick über die Bedeutung der Fügetechnik in Wasserstofftechnologien und über zukünftige Herausforderungen. Fügetechnologien, insbesondere die Schweißtechnik, haben dabei wesentliche Bedeutung für die Umsetzung von technischen Komponenten der Wasserstofftechnologien. Forschungsschwerpunkte ergeben sich insbesondere für die Erzeugung und den Transport des Wasserstoffs.
T2 - Vortragsreihe des DVS Bezirksverbandes Mannheim-Ludwigshafen
CY - Online meeting
DA - 27.04.2023
KW - Wasserstoff
KW - Schweißen
KW - Studie
PY - 2023
AN - OPUS4-57411
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Bewertung und Vermeidung von schweißverarbeitungsbedingten Rissen in hochfesten Baustählen
N2 - Die vorliegende Präsentation fasst die Ergebnisse von drei laufenden bzw. beendeten AiF/IGF-Projekten zusammen, die über die Forschungsvereinigung Stahlanwendung FOSTA e.V. an der BAM bearbeitet wurden zum Thema: Bewertung und Vermeidung von schweißverarbeitungsbedingten Rissen in hochfesten Baustählen.
T2 - FOSTA Tagung: Hochfester Stahl im Stahl und Anlagenbau
CY - Essen, Germany
DA - 16.05.2023
KW - Studie
KW - Schweißen
KW - Hochfester Stahl
KW - Riss
KW - Forschung
PY - 2023
AN - OPUS4-57517
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kromm, Arne
A1 - Mente, Tobias
A1 - Czeskleba, Denis
A1 - Brackrock, Daniel
A1 - Kannengießer, Thomas
T1 - Bauteilversuch zur Bewertung der wasserstoffunterstützten Rissanfälligkeit geschweißter, dickwandiger Offshore-Gründungsstrukturen
N2 - Offshore-Windenergieanlagen erfordern Gründungskonzepte aus unterpulver-(UP-)geschweißten Dickblechen (bspw. der Güte S420ML). Während der Schweißfertigung kann eine zeitverzögerte wasserstoffunterstützte Kaltrissbildung auftreten, deren Bewertung aufgrund der Bauteilgröße von Offshore-Strukturen sehr komplex ist. Deswegen wurde eine bauteilähnliche Geometrie (Mock-Up) entwickelt, um reale Steifigkeitsverhältnisse auf den Labormaßstab zu übertragen. Zusätzliche Versteifungen simulieren die Wirkung einer Einspannung bzw. Schrumpfbehinderung der Schweißnaht. Über die Verwendung von Schweißpulvern mit definierter Feuchte wurden zudem ein Extremszenario der Wasserstoffaufnahme simuliert. Entsprechend der vorgegebenen Mindestwartezeit für die ZfP von bis zu 48 h wurde die Schweißnaht zerstörungsfrei mit Phased-Array-Ultraschall-Prüfung (PAUT) geprüft und die Eigenspannungen über Röntgendiffraktometrie (XRD) bestimmt. Zusätzlich wurde die Wasserstoffverteilung in der Schweißverbindung numerisch simuliert. Außer zulässigen Defekten (wie Poren), wurde keine verzögerte Kaltrissbildung in den Mock-Ups festgestellt, was auf hohe Rissbeständigkeit hindeutet.
T2 - Tagung Werkstoffprüfung 2023
CY - Berlin, Germany
DA - 23.11.2023
KW - Kaltrissbildung
KW - Wasserstoff
KW - Offshore
KW - Schweißen
KW - Bauteiltest
PY - 2023
DO - https://doi.org/10.48447/WP-2023-219
SP - 316
EP - 321
CY - Berlin
AN - OPUS4-58908
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Rimon, Hasia
A1 - Rabin, Ira
ED - Fuller, R.E.
ED - Lange, A.
T1 - Conservation of the Dead Sea Scrolls
N2 - The current state of preservation of the DSS results from the synergetic effect of various factors such as great age, post-discovery treatments, poor storage conditions, environmental influences and exhibitions. With rare exceptions, neither the initial state nor a list of the treatments performed on each DSS fragment is known. Reconstruction of the individual fragment history will have to rely upon advanced analytical techniques to identify the treatments and their effects.
Management of the scrolls may be divided roughly into three periods: a) the scholarly archiving period, from 1948 to the mid-1960s; b) first attempts at conservation, from the mid-1960s to late-1980s; c) Israel Antiquities Authority Scrolls Lab, from 1991 onwards.
KW - Preservation
KW - Dead Sea Scrolls
PY - 2023
SN - 2468-3027
VL - 3D
SP - 102
EP - 105
PB - Brill
CY - Leiden / Boston
AN - OPUS4-58910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Rabin, Ira
ED - Russel, R.E.
ED - Lange, A.
T1 - Ancient Inks
N2 - In the last decade scientists and scholars have accumulated more knowledge on black ink used for writing in Antiquity and the early Middle Ages.
Ready availability of non-destructive testing instruments employed in interdisciplinary projects on historic manuscripts have made it possible to determine the composition of ink and to compare it with the extant records.
KW - Writing Ink
KW - Antiquity
PY - 2023
SN - 2468-3027
VL - 3D
SP - 117
EP - 120
PB - Brill
CY - Leiden / Boston
AN - OPUS4-58913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gräbner, Maraike
T1 - Process optimisation for realisation of crack-free Ni-based wear protection coatings and assessment of machinability by subsequent milling processes to produce defined surfaces
N2 - Reducing CO2 emissions to 62 percent up to 2030 and achieving greenhouse neutrality up to 2050 are the key goals of the EU's climate protection legislation. The expansion of technologies for climate-neutral energy generation is not the only important contribution to reducing greenhouse gases, the efficient use of material systems is also a key factor. In the area of plant engineering, steel components are provided with a wear-protection coating for efficient use to protect them against corrosive, tribological, thermal and mechanical stresses. The wear-protection coatings are primarily made of Co alloys, which are to be replaced by alternative materials, such as nickel alloys, because of the poor working conditions regarding the extraction of the cobalt and because of the health risks. In terms of corrosion behavior, many applications require a crack-free wear protection layer and additional machining. Machining by milling is not economical for wear materials, especially for SME because of the high tool wear, but it is essential to produce defined surfaces with high quality.
Alloy modifications of the filler metals for nickel-based plasma deposition welded wear protection coatings and the use of innovative ultrasonic-assisted milling processes are examined to determine how more favorable machinability can be achieved without reducing the wear protection potential. The focus is on the NiCrSiFeB alloy, which is intended to replace CoCr alloys in the area of screw machines. The modification of hard facing layers in terms of microstructure and precipitation morphology as well as suitability for machining is investigated and compared with the CoCr alloy. In this aspect, the alloy modifications are generated by a PTA process by systematically adjusting the preheating and interpass temperatures, a crack-free wear-resistant layer can be generated, which is subsequently machined by a milling process. In addition to the crack-free properties,
the microstructure, the bonding as well as the mixing between the NiCrFeB alloy and a 1.8550 as well as between the CoCr alloy and a 1.4828 are analyzed and compared in the joining areas. In addition, heating and cooling rates are determined and a chemical analysis of the weld metals is performed. This study provides important knowledge about the differences between NiCrFeB alloy and CoCr alloys in terms of microstructure morphology, bonding and mixing behavior in the joining zones to the basic material.
T2 - 3rd International Conference on Advanced Joining Processes
CY - Braga, Portugal
DA - 19.10.2023
KW - Legierungsmodifikation
KW - Auftragschweißen
KW - Ultraschallunterstütztes Fräsen
KW - Zerspankräfte
PY - 2023
AN - OPUS4-59088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Bauteilversuch zur Bewertung der wasserstoffunterstützten Rissanfälligkeit geschweißter, dickwandiger Offshore Gründungsstrukturen
N2 - Offshore-Windenergieanlagen erfordern Gründungskonzepte aus unterpulver-(UP-)geschweißten Dickblechen (bspw. der Güte S420ML). Während der Schweißfertigung kann eine zeitverzögerte wasserstoffunterstützte Kaltrissbildung auftreten, deren Bewertung aufgrund der Bauteilgröße von Offshore-Strukturen sehr komplex ist. Deswegen wurde eine bauteilähnliche Geometrie (Mock-Up) entwickelt, um reale Steifigkeitsverhältnisse auf den Labormaßstab zu übertragen. Zusätzliche Versteifungen simulieren die Wirkung einer Einspannung bzw. Schrumpfbehinderung der Schweißnaht. Über die Verwendung von Schweißpulvern mit definierter Feuchte wurden zudem ein Extremszenario der Wasserstoffaufnahme simuliert. Entsprechend der vorgegebenen Mindestwartezeit für die ZfP von bis zu 48 h wurde die Schweißnaht zerstörungsfrei mit Phased-Array-Ultraschall-Prüfung (PAUT) geprüft und die Eigenspannungen über Röntgendiffraktometrie (XRD) bestimmt. Zusätzlich wurde die Wasserstoffverteilung in der Schweißverbindung numerisch simuliert. Außer zulässigen Defekten (wie Poren), wurde keine verzögerte Kaltrissbildung in den Mock-Ups festgestellt, was auf hohe Rissbeständigkeit hindeutet.
T2 - Tagung Werkstoffprüfung 2023
CY - Berlin, Germany
DA - 23.11.2023
KW - Kaltrissbildung
KW - Wasserstoff
KW - Offshore
KW - Bauteilversuch
KW - Imperfektion
PY - 2023
AN - OPUS4-58907
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nehring, Grzegorz
T1 - Breaking the limits of the non-destructive instrumental analysis of writing inks
N2 - The ink analysis protocol developed through cooperation between the Bundesanstalt für Materialforschung und -prüfung in Berlin and the Centre for the Study of Manuscript Cultures at the University of Hamburg involves the use of imaging techniques for ink screening, followed by spectroscopic analysis. In our presentation, we will begin by briefly reviewing the history of writing inks and discussing the three main categories: carbon-based inks, plant, and iron-gall inks. We will address their chronology, precursors, and mixed forms, as well as the features that allow for their identification. Then, we will present the techniques we use in ink analysis, whereby we would like to highlight the limitations, advantages, and disadvantages of each approach. Finally, we will discuss the new mass-spectrometric method based on micro-sampling and using atmospheric solid analysis probe (ASAP).
T2 - Future of the Past
CY - Torun, Poland
DA - 14.06.2023
KW - Ink analyses
KW - Spectroscopy
KW - Mass spectroscopy
PY - 2023
AN - OPUS4-58882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giese, Marcel
T1 - Mashining of wear resistant materials by means of ultrasonic assisted milling
N2 - The long-term global goals of achieving almost net zero carbon emissions in the next decades are closely linked to the development of highly efficient components in plant, process and energy engineering, and their sustainable and resource-saving production. Plant components must increasingly withstand tribological loads in addition to high thermal, mechanical, and corrosive stresses. Such combined stresses demand high-performance alloys economically tailored to the application for wear protection and components produced as semi-finished products, via additive manufacturing (AM) or claddings via deposition welding. For instance, the protection of special components made of less cost-intensive materials, e.g., steel in process engineering for screw machines or exhaust gas separation, is feasible applying cost-intensive Ni- or Co-based hard-phase claddings.
Today an increasing number of above-mentioned applications demand precise finishing machining of components to ensure defined compact surfaces with a high integrity and complex contours. Contour milling is standard process for finishing machining of metals. Especially, the desired properties of wear resistant materials (e.g., high strength, hard precipitations) imply significant challenges for milling processes and tools, leading frequently to uneconomic milling conditions due to intolerable high tool wear and surface defects. Inhomogeneous, anisotropic weld structures due to cladding or AM of wear resistance alloys lead to further deteriorations of milling processes due to unstable milling conditions and process forces during chip removal.
To tackle these challenges, already several approaches exist, (1) to enhance machinability of the claddings by alloy modifications to specifically influence solidification and hard phases morphology (precipitation shape, size, distribution) and (2) to achieve significant improvements of the machining situation (e.g., increase of tool life and surfaces integrity) by means of modern hybrid machining processes such as ultrasonic-assisted milling. This contribution shows a comprehensive overview of recent results with these promising approaches for additively welded Ni- CoCr-alloys.
T2 - 24th International Conference on Wear of Materials
CY - Banff, Alberta, Canada
DA - 16.04.2023
KW - Ultrasonic assisted milling
KW - Surface integrity
PY - 2023
AN - OPUS4-58944
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erxleben, Kjell
T1 - Assessment of in-service welding conditions for pressurized hydrogen pipelines via component test
N2 - Hydrogen is the energy carrier of tomorrow for a fossil-free future. This requires a reliable transport infrastructure capable of transporting large quantities of hydrogen. In addition to the construction of new pipelines, the conversion of existing natural gas (NG) networks is an essential part of global hydrogen strategies. The transport of hydrogen is fundamentally different from that of NG, as hydrogen can be absorbed into the pipeline material. Given the known effects of hydrogen embrittlement, the compatibility of the materials for the proposed pipelines (typically low alloy steels in a wide range of strengths and thicknesses) must be investigated. However, pipelines require frequent maintenance, repair, or the need to install additional outlets. In some cases, it is necessary to perform welding on or to the pipelines while they are in-service, i.e. with active gas flow under high pressure. This in-service welding poses challenges for hydrogen operations in terms of additional hydrogen absorption during welding and material compatibility. The challenge can be roughly divided into the possible austenitization of the inner pipe material exposed to hydrogen, which can lead to sufficient hydrogen absorption, and the welding itself, which causes an increased temperature range. Both lead to a significant increase in hydrogen solubility of the respective materials compared to room temperature. In this context, knowledge about welding on hydrogen pipelines is scarce due to the lack of operational experience. Fundamental experimental investigations are required to investigate the transferability from natural gas to hydrogen pipeline networks. For this reason, the present study presents a specially designed demonstrator concept for the realistic assessment of the welding process conditions. The demonstrator was designed ex-post sample extraction for quantification of the absorbed hydrogen concentration. For safety reasons, the required volume of pressurized hydrogen was limited by inserting a solid cylinder. Welding experiments on the DN50 and DN200 pressurized demonstrators showed an increased hydrogen uptake in the welded area of several ppm.
T2 - Materials Week/Steel Innovation
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - In-service
KW - Hydrogen
KW - Pipeline
KW - Repair welding
KW - Component test
PY - 2025
AN - OPUS4-62941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Balzer, R.
A1 - Behrens, H.
A1 - Waurischk, Tina
A1 - Reinsch, Stefan
A1 - Müller, Ralf
A1 - Kiefer, P.
A1 - Deubener, J.
A1 - Fechtelkord, M.
T1 - Water in Alkali Aluminosilicate Glasses
N2 - To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of <4 wt%, and molecular water becomes dominating at water content of >5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses.
KW - NMR spectroscopy
KW - Alkali aluminosilicate glasses
KW - Water speciation
KW - Glass transition
KW - Infrared spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509497
DO - https://doi.org/10.3389/fmats.2020.00085
VL - 7
SP - 85
AN - OPUS4-50949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, R.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Funktional gradierte Materialien auf Basis von Stellite und Stahl im Laserpulver-Auftragschweißen
N2 - Das Hinzufügen von Stellite auf Stahl ist eine typische Vorgehensweise um Bauteile gegen Verschleiß und Korrosion zu schützen. Der Sprung in den Materialeigenschaften kann jedoch zu Rissen und somit zum Versagen der Beschichtung führen. Um die Lebensdauer von Beschichtungen zu erhöhen wird daher ein gradierter Übergang mit verschiedenen Materialpaarungen untersucht.
T2 - 13. Fachtagung Verschleiss- und Korrosionsschutz von Bauteilen durch Auftragschweißen
CY - Haale (Saale), Germany
DA - 22.06.2022
KW - FGM
KW - DED
KW - AM
KW - Functionally Graded Materials
KW - Additive Manufacturing
KW - Directed Energy Deposition
PY - 2022
SP - 66
EP - 73
AN - OPUS4-55504
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simón Muzás, Juan
T1 - Weldability of PBF-LB/M Inconel 718 lattice structures by laser beam
N2 - The present research focuses on the weldability of PBF-LB/M lattice structure parts of Inconel 718 by means of laser beam welding. The integration of complex and lightweight AM structures into assemblies employing conventional joining methods is challenging. During the welding process, dissipation of the laser heat input through thin-walled structures of these lightweight structures is strongly limited, resulting in heat accumulation, atypical cooling rates, and affecting weld geometry, quality of the joint and microstructure. PBF-LB/M parts have been manufactured in three characteristic build directions. They were all stress relieved, then a group of them were submitted to an additional solution annealing and the second group to a two-step aging treatment. Afterwards, these parts were welded to identical PBF-LB/M parts and to wrought ones in butt position. To gain insight into the welding temperature field and to explain segregation mechanisms, grain growth and asymmetries, thermocouples have been attached on the surface’s regions and struts nearby. Joining a lattice structure with a full material wrought sample results in clear asymmetric welds due to dissimilar heat dissipation on both sides of the seam. Selected pre-weld heat treatments have a crucial influence on the quality of the seam on the AM part.
T2 - International Institute of Welding IIW 2023 Conference
CY - Singapore
DA - 16.07.2023
KW - Additive manufacturing (AM)
KW - Laser-based powder bed fusion of metal (PBF-LB/M)
KW - Laser beam welding
KW - Lattice structure
KW - Hybrid part
KW - Heat treatment
KW - Inconel 718
PY - 2023
AN - OPUS4-58017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocaño, Patricia
A1 - Agudo Jácome, Leonardo
T1 - Oxidation Behavior of the AlMo0.5NbTa0.5TiZr Chemically Complex Alloy
N2 - The chemically complex alloys that contain mostly refractory elements (rCCAs), may be highly resistant to heat and load, which makes them attractive candidates for use at extremely high temperatures associated with technological applications such as aeroengine turbines. However, the oxidation behavior remains an emerging field within the CCA community. The fully heat treated AlMo0.5NbTa0.5TiZr rCCA contains a dual-phase microstructure that resembles the γ/ γ’ pattern of the well-known Ni-base superalloys, however with a continuous Al-Zr-Ti-rich B2 ordered matrix embedding Mo-Nb-Ta-rach bcc precipitates. The question thus arises what is the oxidation behavior of this rCCA alloy? In this study, this question is addressed via in situ and ex situ X-ray diffraction (XRD) in dry and humid air in the 800–1000 °C regime. Electron microscopic investigations complement the findings.
In situ synchrotron experiments were carried out at the KMC2 beamline of the Helmholtz Zentrum Berlin (HZB), with a wavelength of 1.5418 Å at 800 and 950 °C under dry and humid (≈ 40% rH, laboratory air) air for 12 h. Scanning and transmission electron microscopy was performed before and after exposure to spatially resolve the scale development ex situ. In general, 12 h exposure led to an oxide scale which internal oxidation reaches several tens of microns, and which is dominated by Zr-, Ti- and Mo-containing oxides although aluminum oxide was also always present. Main differences are observed between temperatures, while the humidity played a lesser role.
T2 - International Conference on High Entropy Materials (ICHEM) 2023
CY - Knoxville, TN, USA
DA - 18.06.2023
KW - High entropy superalloy
KW - High temperature oxidation
KW - In situ synchrotron diffraction
KW - Electron microscopy
PY - 2023
AN - OPUS4-63857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaiser, E.
A1 - Fantin, Andrea
A1 - Manzoni, Anna Maria
A1 - Hesse, René
A1 - Többens, D. M.
A1 - Hsu, W.-C.
A1 - Murakami, H.
A1 - Yeh, A.-C.
A1 - Pavel, M. J.
A1 - Weaver, M. L.
A1 - Zhu, H.
A1 - Wu, Y.
A1 - Vogel, F.
T1 - Elucidating hierarchical microstructures in high entropy superalloys: An integrated multiscale study
N2 - In this study, we examine a high entropy superalloy (HESA-Y1: Ni49.37Co20Cr7Fe4Al11.6Ti6Re1Mo0.5W0.5Hf0.03 at%), focusing on hierarchical microstructure formation and its effects on mechanical properties. Thermodynamic modeling using Thermo-Calc predicts equilibrium phase fractions, compositions, and transition temperatures,which are validated by experimental data from differential scanning calorimetry (DSC). Transmission electronmicroscopy (TEM) reveals that secondary aging induces nanometer-sized γ particles within γ’ precipitates, forming a hierarchical γ/γ’ microstructure. Atom probe tomography (APT) confirms supersaturation of γ’ precipitates with γ-forming elements (Co, Cr, Fe), driving γ particle formation, and measures interfacial widths between γ’ and γ phases. Partitioning coefficients derived from APT align with Thermo-Calc predictions for most elements. Vickers microhardness testing shows an increase of about 50 HV in the hierarchical microstructure compared to the conventional one. In situ synchrotron X-ray diffraction (XRD) from 25 to 750 ◦C determines a small, negative lattice misfit δ between γ and γ’ phases, suggesting enhanced microstructural stability, consistent with Thermo-Calc calculations. Our methodological approach enables measurement of the unconstrained lattice parameter of phase-extracted γ’ in a single-crystal XRD setup. Due to their small size and low volume fraction, γ particles do not produce distinct reflections in the X-ray diffractogram. Elucidating hierarchical microstructures across multiple scales, we establish that the presence of Re and Hf and controlled aging processes lead to enhanced mechanical properties, offering valuable insights for the design of advanced high entropy superalloys.
KW - High entropy alloys
KW - Transmission electron microscopy
KW - X-ray diffraction
KW - Superalloy
PY - 2025
DO - https://doi.org/10.1016/j.matchar.2024.114642
VL - 220
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-62348
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Mohring, Wencke
A1 - Hesse, René
A1 - Agudo Jácome, Leonardo
A1 - Stephan-Scherb, C.
T1 - Early material damage in equimolar CrMnFeCoNi in mixed oxidizing/sulfiding hot gas atmosphere
N2 - The challenges to use more varied fuels at medium and high temperatures above 500 °C need to be addressed by tuning the materials toward a better resistance against increased corrosion. As a first step the corrosion processes need to be better understood, especially in the case of the unavoidable and highly corrosive sulfur-based gases. Herein, oxidation/sulfidation of an equimolar CrMnFeCoNi high-entropy alloy is studied at an early stage after hot gas exposure at 600 °C for 6 h in 0.5% SO2 and 99.5% Ar. The oxidation process is studied by means of X-ray diffraction, scanning and transmission electron microscopy, and supported by thermodynamic calculations. It is found that the sulfur does not enter the bulk material but interacts mainly with the fast-diffusing manganese at grain boundary triple junctions at the alloy surface. Submicrometer scaled Cr–S–O-rich phases close to the grain boundaries complete the sulfur-based phase formation. The grains are covered in different Fe-, Mn-, and Cr-based spinels and other oxides.
KW - High entropy alloy
KW - Sulfiding
KW - Corrosion
KW - Transmission electron microscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543495
DO - https://doi.org/10.1002/adem.202101573
SN - 1527-2648
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54349
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Effect of a mixed atmosphere H2O-O2-SO2 on the oxidation kinetics and phase formation on CrMnFeCoNi and CrCoNi
N2 - The high-temperature corrosion behaviors of the equimolar CrCoNi medium- and CrMnFeCoNi high-entropy alloy were studied in a gas atmosphere consisting of a volumetric mixture of 10% H2O, 2% O2, 0.5% SO2, and 87.5% Ar at 800 °C for up to 96 h. Both alloys were initially single-phase fcc structured and showed a mean grain size of ~50 µm and a homogeneous chemical composition. The oxide layer thickness of the Cantor alloy CrMnFeCoNi increased linearly with exposure time while it remained constant at ~1 µm for CrCoNi. A Cr2O3 layer and minor amounts of (Co,Ni)Cr2O4 developed on CrCoNi while three layers were detected on the Cantor alloy. These layers were a thin and continuous chromium rich oxide layer at the oxide/alloy interface, a dense (Mn,Cr)3O4 layer in the center and a thick and porous layer of Mn3O4 and MnSO4 at the gas/oxide interface. Additionally, a few metal sulfides were observed in the CrMnFeCoNi matrix. These results were found to be in reasonable agreement with thermodynamic calculations.
T2 - ICHEM 2023
CY - Knoxville, TN, USA
DA - 18.06.2023
KW - High entropy alloys
KW - Chemically complex alloys
KW - Corrosion
KW - Mixed gas atmosphere
PY - 2023
AN - OPUS4-57776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Buchholz, Michelle
T1 - Dual Fluorescent Molecularly Imprinted Polymers (MIPs) for Detection of the Prevalent Anti-Inflammatory Drug Diclofenac
N2 - Ensuring the purity of air and water is essential for the overall well-being of life on earth and the sustainability of the planet's diverse ecosystems. To achieve the goal of zero pollution, as outlined in the 2020 European Green Deal by the European Commission,[1] significant efforts are in progress. A key aspect of this commitment involves advancing more efficient and economically viable methods for treating wastewater. This includes the systematic monitoring of harmful pollutants such as heavy metals, microplastics, pesticides, and pharmaceuticals.
One example is the presence of the anti-inflammatory drug diclofenac in water systems, primarily originating from its use as a gel or lotion for joint pain treatment. Diclofenac contamination in surface waters has been detected at approximately 10 μg L-1 (0.03 μM)[2] which is not solely due to widespread usage but also because of the drug's resistance to microbial degradation. Conventional wastewater treatment plants (WWTPs), which rely on biodegradation, sludge sorption, ozone oxidation, and powdered activated carbon treatment, struggle to efficiently remove diclofenac from wastewater.[3],[4] For instance, to enable WWTPs to efficiently monitor and optimize their processes, it would be advantageous to develop on-site detection and extraction methods for persistent pharmaceutical residues in aqueous samples.
In this work, a sol-gel process was used to prepare Nile blue-doped silica nanoparticles (dSiO2-NPs) with a diameter of ca. 30 nm that were further functionalized to enable reversible-addition-fragmentation chain-transfer (RAFT) polymerization. To achieve fluorescence detection, a fluorescent monomer was used as a probe for diclofenac in ethyl acetate, generating stable complexes through hydrogen bond formation. The diclofenac/fluorescent monomer complexes were imprinted into thin molecularly imprinted polymer (MIP) shells on the surface of the dSiO2-NPs. Thus, the MIP binding behaviour could be easily evaluated by fluorescence titrations to monitor the spectral changes upon addition of the analyte. Doping the core substrate with Nile blue generates effective dual fluorescent signal transduction. This approach does not solely depend on a single fluorescence emission band in response to analyte recognition. Instead, it enables the fluorescent core to function as an internal reference, minimizing analyte-independent factors such as background fluorescence, instrumental fluctuation, and operational parameters.[5] Rebinding studies showed that the MIP particles have excellent selectivity towards the imprinted template and good discrimination against the competitor ibuprofen, with a discrimination factor of 2.5. Additionally, the limit of detection was determined to be 0.6 μM. Thus, with further optimization of the MIP, there is potential for the development of a MIP-based biphasic extract-&-detect fluorescence assay for simple, sensitive and specific sensing of diclofenac in aqueous samples down to the required concentrations of 0.03 μM.
T2 - MIP2024: The 12th International Conference on Molecular Imprinting
CY - Verona, Italy
DA - 18.06.2024
KW - Sensor
KW - Diclofenac
KW - Molecularly Imprinted Polymers
KW - Fluorescence
KW - Pollutant
PY - 2024
AN - OPUS4-60439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Early Material Damage in Equimolar CrMnFeCoNi in Mixed Oxidizing/Sulfiding Hot Gas Atmosphere
N2 - The challenges to use more varied fuels at medium and high temperatures above 500 °C need to be addressed by tuning the materials towards a better resistance against increased corrosion. As a first step the corrosion processes need to be better understood, especially in the case of the unavoidable and highly corrosive sulfur-based gases. In this work oxidation/sulfidation of an equimolar CrMnFeCoNi high entropy alloy is studied at an early stage after hot gas exposure at 600 °C for 6 h in 0.5% SO2 and 99.5% Ar. The oxidation process is studied by means of x-ray diffraction, scanning and transmission electron microscopy and supported by thermodynamic calculations. It is found that the sulfur does not enter the bulk material but interacts mainly with the fast-diffusing manganese at grain boundary triple junctions at the alloy surface. Sub-micrometer scaled Cr-S-O rich phases close to the grain boundaries complete the sulfur-based phase formation. The grains are covered in different Fe, Mn and Cr based spinels and other oxides.
T2 - Priority Programme (Schwerpunktprogramm) Compositionally Complex Alloys - High Entropy Alloys (SPP CCA - HEA)
CY - Bayreuth, Germany
DA - 12.07.2022
KW - High entropy alloy
KW - Corrosion
KW - Sulfiding
KW - Cantor alloy
KW - Transmission electron microscopy
PY - 2022
AN - OPUS4-55395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmusto, Juho
T1 - The effect of humidity on the initial oxidation of the refractory high-entropy superalloy AlMo0.5NbTa0.5TiZr
N2 - Unlike conventional alloys, which typically consist of one main element, high-entropy alloys (HEAs) contain five or more principal elements. When compared with conventional alloys, HEAs may possess desirable properties such as improved strength/hardness, remarkable wear resistance, high structural stability, and notable oxidation resistance. However, due to the numerous possibilities of alloy composition, only a small fraction of HEAs has been characterized in terms of their mechanical and chemical properties. A refractory high-entropy superalloy AlMo0.5NbTa0.5TiZr, with its superalloy-like microstructure, belongs to the first group of a subclass of such Al-containing refractory HEAs that has recently drawn attention. The alloy has a nanoscale microstructure consisting of B2 and bcc phases, enabling high-temperature compressive strengths beyond conventional Ni-based alloys. This feature could improve turbine efficiency in the aerospace and power production industries. However, the microstructure has been reported to be sensitive to heat treatment after which it loses mechanical performance when the intragranular hexagonal Al-Zr-based intermetallic forms. This might be connected with the phase stability in the material. Then again, the addition of Al has been reported to improve the oxidation resistance of the material, but also that HEA materials tend to show pronounced zones of internal aging caused by diffusion during oxidation. These previous results imply that further research on the thermodynamic stability of the alloy is required. Furthermore, the oxidation behavior (both external and internal) and the role of humidity in the process are not fully understood. With such a multi-component material, the grain boundaries are expected to play a key role in the oxidation process, serving as short-circuit pathways for diffusion.
To shed more light on the oxidation behavior of the AlMo0.5NbTa0.5TiZr alloy, experiments were carried out for 24 hours at 800 °C under both dry (21% O2 + 79% N2) and humid (8% O2 + 74% N2 + 18% H2O) atmospheres. After the experiments, the samples were characterized with XRD, SEM-EDS, and EPMA.
The alloy oxidized rapidly under both studied atmospheres, resulting in a visibly oxidized region with a thickness of around 1.5 microns (dry) and 3.8 microns (humid). The porosity of the oxidized regions differs from one another: a thin layer of pores was detected in the outermost part of the oxidized zone under dry conditions, whereas the pores were distributed throughout the oxidized zone under humid conditions. Furthermore, the presence of humidity affected the phase formation. The grain boundaries, while still recognizable, differed visually from the grains in the as-received material, indicating the active role of grain boundaries during the oxidation. In addition, in the exposed samples, cracks along the grain boundaries were detected. Interestingly, cracks were also located within the grains. This could originate from the diffusion of species from the grains to the grain boundaries, which has changed the composition of grains. As a consequence, cracks formed most likely during cooling due to the Pilling-Bedworth effect. The formation of cracks suggested that the macro-scale homogeneity of the material may change during operation at high temperatures due to the active grain boundaries.
T2 - High Temperature Corrosion and Oxidation 2023 Workshop
CY - Marktheidenfeld, Germany
DA - 25.09.2023
KW - High-Entropy superalloy
KW - Oxidation behavior
KW - Grain boundaries
KW - Microstructure Evolution
KW - High-Temperature Performance
PY - 2023
AN - OPUS4-63850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - Incipient Oxidation and Deformation Mechanisms of the Chemically Complex Alloy AlMo 0.5 NbTa 0.5 TiZr in the high temperature regime
N2 - The development of refractory chemically complex alloys (rCCAs) has been explored for potential use in high temperature applications. An example of this is the AlMo0.5NbTa0.5TiZr alloy. It was named as “high entropy superalloy” as it resembles the well-known γ/γ’ microstructure in Ni-Base superalloys with cuboidal particles embedded in a continuous matrix. However, the continuous phase in Ni Base alloys is an fcc solution and the cuboidal γ’ precipitates present the L12 intermetallic structure. On the opposite, this CCA has a reversed microstructure where the continuous matrix is formed by an ordered B2 phase which contains cuboidal precipitates of a disordered BCC phase. Some of the most importat results of microstructural analysis, creep test and oxidation are presented in the following work. The as-cast sample shows a bcc/B2 structure with hexagonal phase precipitates in amorphous state whereas the annealed sample also shows a combination of these phases but with larger bcc precipitates and a fully crystallized hexagonal intermetallic. It was found that porosity was higher in the annealed samples (Kinkerdall effect) and the hardness was higher in samples with faster cooling rate due smaller nanostructure. Norton plots show both diffusion and dislocation controlled deformation, and it was found different kinetics between dry and humid air oxidation with the presence of spallation.
T2 - CONVEMI 2021 (Venezuelan congress of microscopy and microanalysis)
CY - Online meeting
DA - 29.10.2021
KW - High entropy superalloys
KW - Mechanical properties
KW - Oxidation behavior
KW - Microstructural analysis
PY - 2021
AN - OPUS4-54382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Heat-driven synthesis of gold nanoparticles from gold microparticles in an e-beam of an SEM
N2 - The synthesis of gold nanoparticles from a microparticle precursor were done by illuminating the precursor with an e-beam in an SEM. To understand the driving physical mechanism, a model for thermodynamic calculation were set up and solved numerically. The results support not charging, but heat as the main mechanism.
T2 - IFW annual PhD seminar
CY - Görlitz, Germany
DA - 22.10.2024
KW - Heat-driven synthesis
KW - Scanning Electron Microscopy
KW - Nanoparticle synthesis
PY - 2024
AN - OPUS4-61834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, F.
A1 - Ngai, S.
A1 - Zhou, X. Y.
A1 - Zaiser, E.
A1 - Manzoni, Anna Maria
A1 - Wu, Y.
A1 - Zheng, W. W.
A1 - Zhang, P.
A1 - Thompson, G. B.
T1 - Tracking maze-like hierarchical phase separation behavior in a Fe-Si-V alloy
N2 - Optimizing the properties of next-generation high-temperature and corrosion-resistant alloys is rooted in balancing structure-property relationships and phase chemistry. Here, we implement a complementary approach based on transmission electron microscopy (TEM) and atom probe tomography (APT) to ascertain aspects of hierarchical phase separation behavior, by understanding the microstructural evolution and the three-dimensional (3D) nanochemistry of a single crystal Fe79.5Si15.5V5.0 (at%) alloy. A maze-like hierarchical microstructure forms, in which a complex network of metastable disordered α plates (A2 phase) emerges within ordered α1 precipitates (D03 phase). The supersaturation in α1 (D03) precipitates with Fe and V drives the formation of α (A2) plates. The morphology of α (A2) plates is discussed concerning crystal structure, lattice misfit, and elastic strain. Phase compositions and a ternary phase diagram aid the thermodynamic assessment of the hierarchical phase separation mechanism via the Gibbs energy of mixing. A perspective on the stabilization of hierarchical microstructures beyond Fe79.5Si15.5V5.0 is elaborated by comparing hierarchical alloys. We find that the ratio of elastic anisotropy (Zener ratio) serves as a predictor of the hierarchical particles’ morphology. We suggest that the strengthening effect of hierarchical microstructures can be harnessed by improving the temporal and thermal stability of hierarchical particles. This can be achieved through phase-targeted alloying aiming at the hierarchical particles phase by considering the constituents partitioning behavior. Beyond Fe79.5Si15.5V5.0, our results demonstrate a potential pathway for improving the properties of high-temperature structural materials.
KW - Atom probe tomography
KW - Transmission electron microscopy
KW - Hierarchical microstructure
KW - Phase separation
PY - 2023
DO - https://doi.org/10.1016/j.jallcom.2023.172157
SN - 0925-8388
VL - 968
SP - 1
EP - 17
PB - Elsevier B.V.
AN - OPUS4-58343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oskolkova, Tatiana O.
A1 - Matiushkina, Anna
A1 - Borodina, Lyubov' N.
A1 - Smirnova, Ekaterina S.
A1 - Dadadzhanova, Antonina I.
A1 - Sewid, Fayza A.
A1 - Veniaminov, Andrey V.
A1 - Moiseeva, Ekaterina O.
A1 - Orlova, Anna O.
T1 - FRET‐Amplified Singlet Oxygen Generation by Nanocomposites Comprising Ternary AgInS2/ZnS Quantum Dots and Molecular Photosensitizers
N2 - Antibacterial photodynamic therapy (a‐PDT) has emerged as a promising non‐invasive therapeutic modality that utilizes the combination of a photosensitive agent, molecular oxygen, and excitation light to generate reactive oxygen species (ROS), demonstrating remarkable activity against multidrug‐resistant bacterial infections. However, the effective use of conventional photosensitizers is significantly limited by a number of their shortcomings, namely, poor water solubility and low selectivity. Herein, we present a novel biocompatible water‐soluble nanocomposite based on hydrophobic tetraphenylporphyrin (TPP) molecules and hydrophilic ternary AgInS2/ZnS quantum dots incorporated into a chitosan matrix as an improved photosensitizer for a‐PDT. We demonstrated that TPP molecules could be successfully transferred into chitosan solution while remaining primarily in the form of monomers, which are capable of singlet oxygen generation. We performed a detailed analysis of the Förster resonance energy transfer (FRET) between quantum dots and TPP molecules within the nanocomposite and proposed the mechanism of the singlet oxygen efficiency enhancement via FRET.
KW - Nano
KW - Particle
KW - Quantum dot
KW - Fluorescence
KW - Synthesis
KW - Optical spectroscopy
KW - Energy transfer
KW - Quality assurance
KW - Lifetime
KW - Quantum yield
PY - 2024
DO - https://doi.org/10.1002/cnma.202300469
SN - 2199-692X
VL - 10
IS - 3
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-59728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - (Nano-)Partikel-Tracking-Analyse (PTA/NTA)
N2 - Einführung in die Partikelgrößenbestimmung von (Nano)Materialien mittels NTA/PTA. Normative Grundlagen (ISO 19430:2016 und ASTM E2834), Messprinzip, Messgeräte, Einflussfaktoren und Besonderheiten, Implementierung, Informationsgehalt der Daten, Reporting.
T2 - BAM Akademie: Info-Tage "NANO OR NOT NANO"
CY - Online meeting
DA - 16.02.2023
KW - Partikelgrößenbestimmung
KW - Partikelkonzentration
KW - Nano
KW - Standardisierung
KW - Brownsche Molekularbewegung
KW - Lichtstreuung
PY - 2023
AN - OPUS4-59132
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grauel, Bettina
A1 - Würth, Christian
A1 - Homann, C.
A1 - Krukewitt, Lisa
A1 - Andresen, Elina
A1 - Roik, Janina
A1 - Recknagel, Sebastian
A1 - Haase, M.
A1 - Resch-Genger, Ute
T1 - Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals
N2 - Despite considerable advances in synthesizing high-quality core/shell upconversion (UC) nanocrystals (NC; UCNC) and UCNC photophysics, the application of near-infrared (NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence (UCL) of UCNC of small size or thin protecting shell. To obtain deeper insights into energy transfer and surface quenching processes involving Yb3+ and Er3+ ions, we examined energy loss processes in differently sized solid core NaYF4 nanocrystals doped with either Yb3+ (YbNC; 20% Yb3+) or Er3+ (ErNC; 2% Er3+) and co-doped with Yb3+ and Er3+ (YbErNC; 20% Yb3+ and 2% Er3+) without a surface protection shell and coated with a thin and a thick NaYF4 shell in comparison to single and co-doped bulk materials. Luminescence studies at 375 nm excitation demonstrate backenergy transfer (BET) from the 4G11/2 state of Er3+ to the 2F5/2 state of Yb3+, through which the red Er3+ 4F9/2 state is efficiently populated. Excitation power density (P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and threephotonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+ emission.
The intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC core. We provide a threedimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC.
KW - Nano
KW - Nanomaterial
KW - Upconversion
KW - Nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Pphotophysics
KW - Lifetime
KW - Sensor
KW - Excitation
KW - Power density
KW - Single particle
KW - Brightness
KW - NIR
KW - Mechanism
KW - Modeling
KW - Simulation
KW - Energy transfer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535317
DO - https://doi.org/10.1007/s12274-021-3727-y
SN - 1998-0124
VL - 15
IS - 3
SP - 2362
EP - 2373
PB - Springer
AN - OPUS4-53531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, R.
A1 - Fa, X.
A1 - Yang, J.
A1 - Cheng, Z.
A1 - Ansari, A. A.
A1 - Ou, Jun
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Preparation of core–shell structured NaYF4:Yb3+/ Tm3+@NaYF4:Yb3+/Er3+ nanoparticles with high sensitivity, low resolution and good reliability and application of their fluorescence temperature properties
N2 - A series of NaYF4:Yb3+/Tm3+@NaYF4:Yb3+/Er3+ nanoparticles doped with Tm3+ and Er3+ were successfully prepared by the solvothermal method. Under 980 nm laser excitation, intense upconversion emission peaks of Tm3+ and Er3+ were observed for all samples. By doping Tm3+ and Er3+ with core–shell partitioning, not only a significant increase in fluorescence intensity could be achieved, but also simultaneous temperature measurements on multiple thermocouple energy levels could be realised. In addition, the temperature sensing performance of different thermocouple energy levels was also investigated, and it was found that the 3 F3 → 3 H6 and 1 G4 → 3 F4 thermocouple energy level pairs of Tm3+ were the best, with maximum absolute sensitivity and maximum relative sensitivity of up to 0.0250 K−1 and 2.155% K−1 respectively, higher than the sensitivity of other thermocouple energy levels. It has a temperature resolution of less than 0.0139 K, which is lower than that of most materials available today. By using this material as a probe to build a fiber optic temperature sensor platform, it was found to have reliable temperature measurement performance.
KW - Flourescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Temperature
KW - Nano
KW - Particle
KW - Upconversion
KW - Lanthanide
KW - Qantum yield
KW - Quality assurance
KW - Monitoring
KW - Infrastructure
PY - 2022
DO - https://doi.org/10.1039/d1ce01729b
VL - 24
IS - 9
SP - 1752
EP - 1763
PB - RSC Publishing
AN - OPUS4-54416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ahiboz, D.
A1 - Andresen, Elina
A1 - Manley, P.
A1 - Resch-Genger, Ute
A1 - Würth, Christian
A1 - Becker, C.
T1 - Enhanced photon upconversion using erbium-doped nanoparticles interacting with silicon metasurfaces
N2 - Photon upconversion (UC) using trivalent erbium (Er+3) doped crystals is a promising concept to harness near infrared photons of the solar spectrum which cannot be directly absorbed by silicon solar cells. However, their UC efficiency at low-intensity 1 sun illumination is not relevant on device level so far. Exploiting giant near-field enhancement effects on metasurfaces is an appealing approach to enable efficient UC at low irradiance conditions. Here, we report on more than 1000-fold enhanced photon UC of NaYF4:Er+3 nanoparticles interacting with the near-fields supported by a silicon metasurface under 1550 nm excitation.
T2 - 48th Photovoltaic Specialists Conference (PVSC)
CY - Online meeting
DA - 20.06.2021
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Excitation power density
KW - Brightness
KW - NIR
KW - Mechanism
KW - Modeling
KW - Simulation
KW - Energy transfer
KW - Photonic crystal
KW - Enhancement strategy
PY - 2021
DO - https://doi.org/10.1109/pvsc43889.2021.9518495
SP - 1
EP - 3
PB - IEEE
CY - Berlin
AN - OPUS4-53786
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bandi, V.G.
A1 - Luciano, M.P.
A1 - Saccomano, M.
A1 - Patel, N.L.
A1 - Bischof, Th. S.
A1 - Lingg, J.G.P.
A1 - Tsrunchev, P.T.
A1 - Nix, M.N.
A1 - Ruehle, Bastian
A1 - Sanders, C.
A1 - Riffle, L.
A1 - Robinson, C.M.
A1 - Difilippantonio, S.
A1 - Kalen, J.D.
A1 - Resch-Genger, Ute
A1 - Ivanic, J.
A1 - Bruns, O.T.
A1 - Schnermann, M.
T1 - Targeted multicolor in vivo imaging over 1,000 nm enabled by nonamethine cyanines
N2 - Recent progress has shown that using wavelengths between 1,000 and 2,000 nm, referred to as the shortwave-infrared or near-infrared (NIR)-II range, can enable high-resolution in vivo imaging at depths not possible with conventional optical wavelengths.
However, few bioconjugatable probes of the type that have proven invaluable for multiplexed imaging in the visible and NIR range are available for imaging these wavelengths. Using rational design, we have generated persulfonated indocyanine dyes with absorbance maxima at 872 and 1,072 nm through catechol-ring and aryl-ring fusion, respectively, onto the nonamethine scaffold. Multiplexed two-color and three-color in vivo imaging using monoclonal antibody and dextran conjugates in several tumor models illustrate the benefits of concurrent labeling of the tumor and healthy surrounding tissue and lymphatics.
These efforts are enabled by complementary advances in a custom-built NIR/shortwave-infrared imaging setup and software package for multicolor real-time imaging.
KW - Photoluminescence
KW - Fluorescence
KW - Dye
KW - Cyanine
KW - Antibody
KW - Bioconjugate
KW - Conjugate
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - SWIR
KW - Mechanism
KW - Imaging
KW - Application
KW - Contrast agent
KW - Bioimaging
PY - 2021
DO - https://doi.org/10.1038/s41592-022-01394-6
VL - 19
IS - 3
SP - 353
EP - 358
PB - Nature Research
AN - OPUS4-54465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maisuls, I.
A1 - Wang, Cui
A1 - Gutierrez Suburu, M. E.
A1 - Wilde, S.
A1 - Daniliuc, C.-G.
A1 - Brunink, D.
A1 - Doltsinis, N. L.
A1 - Ostendorp, S.
A1 - Kösters, J.
A1 - Resch-Genger, Ute
A1 - Strassert, C. A.
T1 - Ligand-controlled and nanoconfinement-boosted luminescence employing Pt(II) and Pd(II) complexes: from color-tunable aggregation-enhanced dual emitters towards self-referenced oxygen reporters
N2 - In this work, we describe the synthesis, structural and photophysical characterization of four novel Pd(II) and Pt(II) complexes bearing tetradentate luminophoric ligands with high photoluminescence quantum yields (FL) and long excited state lifetimes (s) at room temperature, where the results were interpreted by means of DFT calculations. Incorporation of fluorine atoms into the tetradentate ligand favors aggregation and thereby, a shortened average distance between the metal centers, which provides accessibility to metal–metal-to-ligand charge-transfer (3MMLCT) excimers acting as red-shifted Energy traps if compared with the monomeric entities. This supramolecular approach provides an elegant way to enable room-temperature phosphorescence from Pd(II) complexes, which are otherwise quenched by a thermal population of dissociative states due to a lower ligand field splitting. Encapsulation of These complexes in 100 nm-sized aminated polystyrene nanoparticles enables concentration-controlled aggregation-enhanced dual emission. This phenomenon facilitates the tunability of the absorption and emission colors while providing a rigidified environment supporting an enhanced FL up to about 80% and extended s exceeding 100 ms. Additionally, these nanoarrays constitute rare examples for selfreferenced oxygen reporters, since the phosphorescence of the aggregates is insensitive to external influences, whereas the monomeric species drop in luminescence lifetime and intensity with increasing triplet molecular dioxygen concentrations (diffusion-controlled quenching).
KW - Fluorescence
KW - Multiplexing
KW - Lifetime
KW - Bead
KW - Particle
KW - Dye
KW - Barcoding
KW - Encoding
KW - Quantum yield
KW - Label
KW - Reporter
KW - Pd(II)
KW - Pt(II)
KW - Complex
KW - NMR
KW - X-ray
KW - Sythesis
KW - Aggregation
KW - Monomer
KW - Color
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525288
DO - https://doi.org/10.1039/d0sc06126c
VL - 12
IS - 9
SP - 3270
EP - 3281
PB - Royal Society of Chemistry
AN - OPUS4-52528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Würth, Christian
A1 - Pauli, Jutta
A1 - Weigert, Florian
T1 - Quantitative optical-spectroscopic characterization of luminescent nanomaterials - Photoluminescence Quantum Yields
N2 - Accurate and quantitative photoluminescence measurements are mandatory for the comparison of different emitter classes and the rational design of the next generation of molecular and nanoscale reporters as well as for most applications relying on their luminescence features in the life and material sciences and nanobiophotonics. In the following, procedures for the determination of the spectroscopic key parameter photoluminescence quantum yield, i.e., the number of emitted per absorbed photons, in the UV/vis/NIR/SWIR are presented including pitfalls and achievable uncertainties and material-specific effects related to certain emitter classes are addressed. Special emphasis is dedicated to luminescent nanocrystals.
T2 - International Workshop on "Emerging Nanomaterials for Displays and SSL"
CY - Dresden, Germany
DA - 11.11.2021
KW - Nano
KW - Nanomaterial
KW - Nanocrystal
KW - Semiconductor quantum dot
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Surface chemistry
KW - Brightness
KW - NIR
KW - SWIR
KW - Method
KW - Uncertainty
KW - Rreference material
PY - 2021
AN - OPUS4-53783
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Design, characterization, and application of fluorescent sensor particles
N2 - pH and oxygen are amongst the most important and frequently measured analytes in the life and material sciences, indicating, e.g., diseases and corrosion processes. This includes the optical monitoring of pH in living cells for studying cellular internalization pathways, such as phagocytosis, endocytosis, and receptor ligand internalization with the aid of molecular and nanoscale fluorescent sensors. Nanoparticle (NP)-based sensors, that are labeled or stained with a multitude of sensor dyes, have several advantages as compare to conventional molecular probes like enhanced brightness, i.e., amplified signals, ease of designing ratiometric systems by combining analyte sensitive and inert reference dyes, and increased photostability. Moreover, this can enable the use of hydrophobic dyes in aqueous environments. Versatile templates and carriers for the fabrication of nanosensors by the staining and/or labelling with different fluorophores and sensor molecules or surface functionalized NP like silica (SiO2-NP) and polystyrene (PS-NP) particles provide. Here we present the design of a versatile platform of color emissive nanosensors and stimuli-responsive microparticles for the measurement of pH, oxygen, and other targets utilizing both types of matrices and sets of spectrally distinguishable sensor and reference dyes and their characterization and demonstrate the applicability of representative sensor particle for cellular studies.
T2 - Vortrag bei dem Projekttreffen MicraGen
CY - Copenhagen, Denmark
DA - 18.08.2022
KW - Dye
KW - Luminescence
KW - Quantitative spectroscopy
KW - Photophysics
KW - Quality assurance
KW - Nano
KW - Particle
KW - Quantum yield
KW - Lifetime
KW - Standard
KW - Integrating sphere spectroscopy
KW - Sensor
KW - pH
KW - Oxygen
KW - Microfluidics
KW - Cancer
KW - Cell
KW - Life sciences
PY - 2022
AN - OPUS4-57049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, P.
A1 - Morales-Marquez, R.
A1 - Cervas, G.
A1 - Hernandez Medel, A.
A1 - Ogayar, M. P.
A1 - Jimenez de Aberasturi, D.
A1 - de Isidro-Gomez, A. I.
A1 - Torres-Padro, A.
A1 - Palomares, F. J.
A1 - Garcia-Orrit, S.
A1 - Sousa, C. T.
A1 - Espinosa, A.
A1 - Telle, H. H.
A1 - Ortgies, D. H.
A1 - Vega-Mayoral, V.
A1 - Cabanillas-Gonzalez, J.
A1 - Rodriguez, E. M.
A1 - Resch-Genger, Ute
A1 - Wegner, Karl David
A1 - Juarez, B. H.
T1 - The role of temperature in the photoluminescence quantum yield (PLQY) of Ag2S-based nanocrystals
N2 - Highly emissive Ag2S nanocrystals (NCs) passivated with a gradated shell incorporating Se and Zn were synthesized in air, and the temperature dependence of their photoluminescence quantum yield (PLQY) was quantified in both organic and aqueous media at B1200 nm. The relevance of this parameter, measured at physiological temperatures, is highlighted for applications that rely on the near infrared (NIR) photoluminescence of NCs, such as deep NIR imaging or luminescence nanothermometry. Hyperspectral NIR imaging shows that Ag2S-based NCs with a PLQY in organic media of about 10% are inefficient for
imaging at 40 8C through 20 mm thick tissue with low laser irradiation
power densities. In contrast, water-transferred Ag2S-based NCs with an
initial PLQY of 2% in water exhibit improved robustness against temperature changes, enabling improved imaging performance.
KW - Quantum dots
KW - Ag2S
KW - Fluorescence
KW - Nanomaterial design
KW - Advanced nanomaterials
KW - Shortwave infrared (SWIR)
KW - Temperature sensing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613877
DO - https://doi.org/10.1039/D4MH01016G
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Amorphous, fluorescent silica particles for bioimaging applications
N2 - Nowadays amorphous silica nanoparticles (SiO2 NP) are one of the most abundant engineered nanomaterials, with an annual production of hundreds of thousands of tons, that are used in a broad field of industrial products and processes. Since SiO2 NP are highly stable and easily produced on a large scale at low cost, they are widely employed as fillers for rubbers and composites, absorbents, catalysts, advanced coating additives as well as plant growth agents in agriculture, anti-caking agents in food products, or as carrier material in cosmetic industry. Moreover, they are promising candidates for colloidal scaffolds in biomedical applications like bioimaging, sensing or controlled drug delivery. SiO2 NP modified with luminescent chromophores have several advantages as compared to conventional molecular probes like enhanced brightness, ease of designing ratiometric systems, and increased photostability. Here we present our work on multicolored SiO2 NP for imaging and sensing applications.
T2 - FUNGLASS Workshop
CY - Berlin, Germany
DA - 06.03.2024
KW - Sensors
KW - Nano
KW - Particles
KW - Silica
KW - Luminescence
KW - Fluorescence
KW - Quality assurance
KW - Method
KW - Synthesis
KW - Dye
KW - pH
KW - Surface analysis
PY - 2024
AN - OPUS4-62167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Krappe, Alexander R.
A1 - Fürstenwerth, Paul C.
A1 - Brosius, Amelie L.
A1 - Fasting, Carlo
A1 - Hoffmann, Kurt F.
A1 - Resch-Genger, Ute
A1 - Eigler, Siegfried
A1 - Steinhauer, Simon
A1 - Riedel, Sebastian
T1 - Luminescent Perhalofluoro Trityl Radicals
N2 - In this proof-of-concept study, we show that polyfluorinated trityl radicals with the, to this date, highest fluorination grade can be accessed in quantitative yields in a straightforward manner starting from the perfluorinated trityl cation. The trityl skeleton is functionalized with trimethylsilyl halides to yield perhalofluoro trityl cations, which are subsequently reduced using commercial zinc powder. In this way, we prepare three perhalofluoro trityl radicals and analyze the impact of the fluorine ligands on their electro-optical properties, revealing some interesting trends. In comparison to literature-known polychlorinated trityl radicals, the new polyfluorinated derivatives exhibit substantially higher fluorescence quantum yields, longer luminescence lifetimes, and an expanded emission range that extends into the yellow spectral region. They further display enhanced photostability under light irradiation. In radical-stained polystyrene nanoparticles, an additional broad emission band in the red−NIR wavelength region is observed, which is attributed to excimer formation. Finally, the stability of the new radicals is investigated under ambient conditions, showing the slow conversion with atmospheric oxygen yielding the respective peroxides, which are characterized by single-crystal X-ray diffraction. All in all, our study extends the present scope of luminescent trityl radicals, as the functionalization of the perfluorinated cationic precursor unlocks the path toward a vast variety of polyfluorinated trityl radicals.
KW - Dye
KW - Fluorescence
KW - Radical
KW - Synthesis
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Polarity
KW - Polymer
KW - Solvatchromism
KW - Excimer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647973
DO - https://doi.org/10.1021/jacs.5c16418
SN - 0002-7863
VL - 147
IS - 46
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-64797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, R.
A1 - Zhenlong, F.
A1 - Yang, J.
A1 - Ansari, A.
A1 - Ou, Jun
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Retracted article: Effect of Ca2+ doping on the upconversion luminescence properties of NaYF4:Yb3+/Tm3+ nanoparticles and study of its temperature measurement performance
N2 - A solvothermal method was used to prepare a series of Yb3+/Tm3+/Ca2+ co-doped NaYF4 nanoparticles with different Ca2+ contents. Strong upconversion blue fluorescence could be observed under 980 nm laser excitation of the samples. The effect of different Ca2+ contents on the luminescence intensity was investigated, and it was found that the UV-vis upconversion luminescence increased and then decreased with an increasing Ca2+ concentration during the increase of the Ca2+ content from 0 mol% to 25 mol%, reaching the strongest fluorescence at 15 mol%, which was up to about 28 times stronger than that without Ca2+ doping. Furthermore, the mechanism was investigated, and it was found that the doping of Ca2+ disrupted the symmetry of the crystal field, resulting in a significant enhancement of the overall fluorescence. Applied to fluorescence intensity ratio thermometry, the absolute and relative sensitivities are as high as 0.0418 K−1 and 2.31% K−1, respectively, with a minimum temperature resolution of 0.0129 K.
KW - Sensor
KW - Temperature
KW - Lanthanide
KW - Luminescence
KW - Nanoparticles
KW - Upconversion
KW - Advanced materials
PY - 2022
DO - https://doi.org/10.1039/D2CE00562J
SN - 1466-8033
VL - 24
IS - 27
SP - 4887
EP - 4898
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-56952
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zavoiura, O.
A1 - Resch-Genger, Ute
A1 - Seitz, O.
T1 - Reactive Quantum Dot-Based FRET Systems
N2 - Oligonucleotide-templated reactions (OTRs) between two reactive hybridization probes allow for the detection of a DNA or RNA of interest by exploiting the target molecule as a catalyst of chemical reactions.
The product of such a reaction commonly exhibits distinct fluorescence properties and can be detected by the means of fluorescence spectroscopy. The vast majority of OTR systems utilize organic dyes as fluorescent reporters. However, the use of brighter emitters, such as semiconductor quantum dots (QDs), has potential to improve the sensitivity of detection by providing brighter signals and permitting the use of probes at very low concentrations. Here we report an RNA-templated reaction between two fluorescently labeled peptide nucleic acid (PNA)-based probes, which proceeds on the surface of a QD. The QD-Bound PNA probe bears a cysteine functionality, while the other PNA is functionalized with an organic dye as a thioester. OTR between these probes proceeds through a transfer of the organic dye to the QD and can be conveniently monitored via fluorescence resonance energy transfer (FRET) from the QD to the Cy5. The reaction was performed in a conventional fluorescence microplate reader and permits the detection of RNA in the picomolar range.
KW - Fluorescence
KW - Nano
KW - Particle quantum dot
KW - FRET
KW - Assay
KW - Sensor
KW - RNA-templated reactions
KW - Bioconjugation
KW - Synthesis
KW - Dye
KW - Click chemistry
KW - Peptide nucleic acid
KW - Quantum dots
KW - RNA
KW - Fluorescence spectroscopy
PY - 2020
DO - https://doi.org/10.1007/978-1-0716-0243-0_11
VL - 2105
SP - 187
EP - 198
PB - Springer Sience+Business Media
AN - OPUS4-50553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bertorelle, F.
A1 - Wegner, Karl David
A1 - Berkulic, M. P.
A1 - Fakhouri, H.
A1 - Comby-Zerbino, C.
A1 - Sagar, A.
A1 - Bernadó, P.
A1 - Resch-Genger, Ute
A1 - Bonacic-Koutecký, V.
A1 - Le Guével, X.
A1 - Antoine, R.
T1 - Tailoring the NIR-II Photoluminescence of Single Thiolated Au25 Nanoclusters by Selective Binding to Proteins
N2 - Atomically precise gold nanoclusters are a fascinating class of nanomaterials that exhibit molecule-like properties and have outstanding photoluminescence (PL). Their ultrasmall size, molecular chemistry, and biocompatibility make them extremely appealing for selective biomolecule labeling in investigations of biological mechanisms at the cellular and anatomical levels. In this work, we report a simple route to incorporate a preformed Au25 nanocluster into a model bovine serum albumin (BSA) protein. A new approach combining small-angle X-ray scattering and molecular modeling provides a clear localization of a single Au25 within the protein to a cysteine residue on the gold nanocluster surface.
Attaching Au25 to BSA strikingly modifies the PL properties with enhancement and a redshift in the second near-infrared (NIR-II) window. This study paves the way to conrol the design of selective sensitive probes in biomolecules through a ligand-based strategy to enable the optical detection of biomolecules in a cellular environment by live imaging.
KW - Fluorescence
KW - Aggregation
KW - Signal enhancement
KW - Cluster
KW - Nano
KW - Metal
KW - NIRII
KW - SWIR
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Synthesis
KW - Protein
KW - Imaging
KW - Bioimaging
KW - Ligand
KW - Gold
PY - 2022
DO - https://doi.org/10.1002/chem.202200570
SN - 1521-3765
VL - 28
IS - 39
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55077
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cheng, Z.
A1 - Meng, M.
A1 - Qiao, X.
A1 - Liu, Y.
A1 - Resch-Genger, Ute
A1 - Ou, J.
T1 - The synthesis of Er3+/Yb3+/K+ triple-doped NaYF4 phosphors and its high sensitivity optical thermometers at low power
N2 - Optical Thermometry is popular among researchers because of its non-contact, high sensitivity, and fast measurement properties. In the present experiment, Er3+/Yb3+/K+ co-doped NaYF4 nanoparticles with different K+ concentrations were synthesized by solvothermal method, and the samples showed bright upconversion green emission under the excitation of a 980 nm laser. The powder X-ray diffractometer and transmission electron microscope were used to characterize the crystal structure and its surface morphology, respectively. The spectral characteristics of nanoparticles with K+ doping concentration from 10% to 30% (Molar ratio) were investigated by fluorescence spectroscopy, and it was observed that the fluorescence intensity reached the maximum at the K+ concentration of 20%, after which the intensity weakened when the K+ content continued to increase. According to the dependence between the luminescence intensity of the sample and the laser power density and fluorescence lifetime, the intrinsic mechanism was carefully investigated. Temperature-dependent spectra of the samples were recorded in the temperature range of 315–495 K, and the maximum values of absolute sensitivity (Sa) and relative sensitivity (Sr) were measured at 0.0041 K−1 (455 K) and 0.9220%K−1 (315 K). The experimental results show that K+/Er3+/Yb3+ triple-doped NaYF4 green fluorescent nanoparticles (GFNs) have good prospects for applications in display devices, temperature sensing, and other fields.
KW - K+ doped
KW - Upconversion luminescence
KW - Optical temperature sensing
KW - Thermal coupling energy level
PY - 2023
DO - https://doi.org/10.1016/j.jallcom.2022.168299
VL - 937
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-57106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Wang, Cui
A1 - You, Y.
A1 - Förster, C.
A1 - Schubert, H.
A1 - Heinze, K.
A1 - Seitz, M.
T1 - NIR-NIR-Aufkonvertierung in molekularen Chrom-Ytterbium-Salzen
N2 - Photonen-Aufkonvertierung in hetero-oligonuklearen, Metallkomplex-Architekturen mit organischen Liganden ist ein interessantes, aber bisher selten beobachtetes Phänomen, trotz des großen Potentials sowohl aus Sicht der Grundlagenforschung als auch aus der Anwendungsperspektive. Nun wurde ein neues photonisches Material aus molekularen Chrom(III)- und Ytterbium(III)-Komplexionen entwickelt.
Dieses zeigt im Festkörper bei Raumtemperatur abhängig von der Anregungsleistungsdichte nach Anregung des 2F7/2! 2F5/2-3berganges des Ytterbiums bei ca. 980 nm eine kooperative Sensibilisierung der Chrom(III)-zentrierten 2E/2T1-Phosphoreszenz bei ca. 775 nm. Der Aufkonvertierungsprozess ist unempfindlich gegenüber Luftsauerstoff und kann in Gegenwart von Wassermolekülen im Kristallgitter beobachtet werden.
KW - Crystal
KW - Sensor
KW - NIR
KW - Yb(III) complex
KW - Cr(III)
KW - Upconversion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517217
DO - https://doi.org/10.1002/ange.202007200
VL - 132
IS - 42
SP - 18804
EP - 18808
PB - Angewandte Chemie
AN - OPUS4-51721
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Wegner, Karl David
A1 - Fischer, C.
A1 - Resch-Genger, Ute
T1 - Exploring Simple Particle-Based Signal Amplification Strategies in a Heterogeneous Sandwich Immunoassay with Optical Detection
N2 - Heterogeneous sandwich immunoassays are widely used for biomarker detection in bioanalysis and medical diagnostics. The high analyte sensitivity of the current “gold standard” enzyme-linked immunosorbent assay (ELISA) originates from the signal-generating enzymatic amplification step, yielding a high number of optically detectable reporter molecules. For future point-of-care testing (POCT) and point-of-need applications, there is an increasing interest in more simple detection strategies that circumvent time-consuming and temperature-dependent enzymatic reactions. A common concept to aim for detection limits comparable to those of enzymatic amplification reactions is the usage of polymer nanoparticles (NP) stained with a large number of chromophores. We explored different simple NP-based signal amplification strategies for heterogeneous sandwich immunoassays
that rely on an extraction-triggered release step of different types of optically detectable reporters. Therefore, streptavidinfunctionalized polystyrene particles (PSP) are utilized as carriers for (i) the fluorescent dye coumarin 153 (C153) and (ii) hemin (hem) molecules catalyzing the luminol reaction enabling chemiluminescence (CL) detection. Additionally, (iii) NP labeling with hemin-based microperoxidase MP11 was assessed. For each amplification approach, the PSP was first systematically optimized regarding size, loading concentration, and surface chemistry. Then, for an immunoassay for the inflammation marker C- eactive protein (CRP), the analyte sensitivity achievable with optimized PSP
ystems was compared with the established ELISA concept for photometric and CL detection. Careful optimization led to a limit of detection (LOD) of 0.1 ng/mL for MP11-labeled PSP and CL detection, performing similarly well to a photometric ELISA (0.13 ng/mL), which demonstrates the huge potential of our novel assay concept.
KW - Nanoparticle
KW - Fluorescence
KW - Immunoassay
KW - Quality assurance
KW - Antibody
KW - Polymer
KW - Dye
KW - Signal enhancement
KW - CRP
KW - Biosensing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597853
DO - https://doi.org/10.1021/acs.analchem.3c03691
SN - 1520-6882
VL - 96
IS - 13
SP - 5078
EP - 5085
PB - American Chemical Society
CY - Columbus, Ohio
AN - OPUS4-59785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Resch-Genger, Ute
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Zou, Shan
A1 - Johnston, Linda
T1 - Behind the Paper: Nanoscale Reference and Test Materials for the Validation of Characterization Methods for Engineered Nanomaterials – Current State, Limitations and Needs
N2 - Engineered nanomaterials (NMs) of different material composition, morphology, and surface chemistry are widely used in material and life sciences. For NM quality control and risk assessment, NM key properties must be characterized with validated methods, requiring reference materials (RMs).
KW - Engineered Nanomaterials
KW - Nanoscale reference materials
KW - Interlaboratory comparisons
KW - Traceability
KW - Standardization and Regulation
KW - Nano
KW - Particle
KW - Quality assurance
KW - Surface chemistry
PY - 2025
UR - https://communities.springernature.com/posts/nanoscale-reference-and-test-materials-for-the-validation-of-characterization-methods-for-engineered-nanomaterials-current-state-limitations-and-needs
SP - 1
EP - 3
PB - Springer Nature
CY - Online
AN - OPUS4-62572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haroun, A. A. A.
A1 - Derbala, H. A.
A1 - Bassioni, G.
A1 - Resch-Genger, Ute
A1 - Shafik, E. S.
A1 - Hassan, A. M. A.
T1 - N-aminophthalimide as a novel UV-stabilizer to promote physico-mechanical properties of highdensity polyethylene (HDPE)
N2 - This study aimed to evaluate the efficacy of Naminophthalimide (NAP) as a novel UV-stabilizer for highdensity polyethylene (HDPE) in improving its physicomechanical properties under UV exposure. NAP was synthesized by interaction between phthalimide and hydrazine hydrate. It was incorporated into HDPE with different weight ratios (1, 1.5, 2, and 3%), and its performancewas compared with Hostavin as a traditional UV stabilizer. The HDPE composites were exposed to UV irradiation for different periods (7 and 14 days) to evaluate their photodegradation behavior. Tensile strength, elongation at break were assessed before and after UV exposure. Also, oxidation induction time (OIT), melt flow rate (MFR), Vicat softening temperature were evaluated. Hostavin incorporation reduced tensile strength from 22.36 to 20.62MPa at higher concentrations. It has been found that 3% Hostavin, significantly improved elongation at break, increasing from 423% to 1,170%, suggesting enhanced flexibility. In contrast, NAP increased tensile strength to 22.9MPa and moderately enhanced elongation but slightly declined at 3%due to potential over-stabilization. Under UV exposure, retained tensile strength and elongation was improved with stabilizer content, which increasing tensile strength retention. The HDPE that containing NAP showed enhanced UV resistance and superior retention of mechanical properties compared to Hostavin.
KW - Polymer
KW - Advanced materials
KW - Quality assurance
KW - Stabilizer
KW - Synthesis
KW - Physico-mechanical properties
PY - 2025
DO - https://doi.org/10.1515/polyeng-2024-0262
SN - 2191-0340
SP - 1
EP - 8
PB - De Gruyter
CY - Berlin
AN - OPUS4-63534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Reliable Photoluminescence Quantum Yields – New Reference Materials and Interlaboratory Comparisons
N2 - The rational design and choice of molecular and nanoscale reporters, the comparison of different emitter classes, and photophysical and mechanistic studies require quantitative photoluminescence measurements and the reliable determination of the key performance parameter photoluminescence quantum yield (QY), i.e., the number of emitted per absorbed photons. This is of special importance for all photoluminescence applications in the life and material sciences in the UV/vis/NIR/SWIR. To improve the reliability and comparability of photoluminescence and QY measurements across laboratories, pitfalls, achievable uncertainties, and material-specific effects related to certain emitter classes must be explored. Also, suitable protocols and reference materials are needed which have been validated in interlaboratory comparisons for different wavelength regions and transparent and scattering luminophores.[1]
Based on absolute and relative photoluminescence measurements of functional dyes and luminescent nanomaterials, reliable methods for determining QY of transparent and scattering luminophores, nonlinear emitters, and solid luminescent nanomaterials have been developed.[1-4] Thereby, material- and method-related uncertainties of relative and absolute QY measurements and achievable uncertainties could be quantified for linear and nonlinear UV/vis/NIR/SWIR emitters and lately for also luminescent and scattering materials and solid phoshors.
In this context, we present the development and certification of a first set of UV/vis/NIR quantum yield standards with a complete uncertainty budget,[5] which present simple tools for a better comparability of QY measurements. In addition, a first interlaboratory comparison of absolute QY measurements of solid and scattering LED converter materials with integrating sphere spectroscopy has been performed.[5] The outcome of this study is presented, thereby addressing common pitfalls and measurement uncertainties and providing recommendations for the performance of reliable QY measurements of linear and non-linear emitters in transparent, scattering, and solid samples.
T2 - Anakon 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Quality assurance
KW - Reference material
KW - Method
KW - Fluorescence
KW - Quantum yield
KW - Absolute
KW - Integrating sphere spectroscopy
KW - Interlaboratory comparison
KW - Dye
KW - Film
KW - Nano
KW - Particle
KW - Scattering
KW - Uncertainty
KW - LED converter
PY - 2025
AN - OPUS4-62792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schweizer, S.
T1 - Interlaboratory comparison on absolute PL quantum yield measurements of scattering luminescent materials
N2 - Optical measurements of scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders play an important role in fundamental research and industry. Typical examples are luminescent nano- and microparticles and phosphors of different composition in different matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter for the performance of these materials is the photoluminescence quantum yield QY, i.e., the number of emitted photons per number of absorbed photons. QY of transparent luminophore solutions can be determined relatively to a fluorescence quantum yield standard of known QY. Such standards are meanwhile available as certified reference materials.[1] The determination of QY of scattering liquid and solid samples like dispersions of luminescent nanoparticles, solid phosphors, and optoceramics requires, however, absolute measurements with an integrating sphere setup. Although the importance of reliable absolute QY measurements has been recognized, no interlaboratory comparisons (ILCs) on measurement uncertainties and the identification of typical sources of uncertainty have been yet reported. Also, no scattering reference materials with known QY are available.
We present here the results of a first ILC of 3 laboratories from academia and industry performed to identify and quantify sources of uncertainty of absolute QY measurements of scattering samples. Thereby, two types of commercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring QY of transparent and scattering dye solutions and solid phosphors. As representative and industrially relevant solid and scattering samples, YAG:Ce optoceramics of varying surface roughness were chosen, applied, e.g., as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank, utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While matching QY values could be obtained for transparent dye solutions and scattering dispersions, here using a blank with scattering properties closely matching those of the sample, QY measurements of optoceramic samples with different blanks revealed substantial differences, with the blank's optical properties accounting for measurement uncertainties of more than 20 %. Based upon the ILC results, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder which reveals a near-Lambertian light scattering behavior, yielding a homogeneous light distribution within the integrating sphere.
T2 - 8th IWASOM
CY - Gdánsk, Poland
DA - 07.07.2024
KW - Nano
KW - Particle
KW - Fluorescence
KW - Quantum yield
KW - Method
KW - Sensor
KW - Film
KW - Absolute quantum yield
KW - Scattering
KW - YAG:Ce
KW - Quality assurance
KW - Lanthanide
KW - Upconverter
KW - LED
KW - Uncertainty
KW - Standardization
KW - Reference material
PY - 2024
AN - OPUS4-62100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Osiopova, Viktoriia
A1 - Tavernaro, Isabella
A1 - Ge, L.
A1 - Kitzmann, W. R.
A1 - Heinze, K.
A1 - Reithofer, M. R.
A1 - Resch-Genger, Ute
T1 - Complete protection of NIR-luminescent molecular rubies from oxygen quenching in air by L-arginine-mediated silica nanoparticles
N2 - The application of emerging luminophores such as near-infrared (NIR) emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion (TTA-UC) systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from uminescence quenching by oxygen. Therefore, we explored the influence of sol–gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles (SiO2 NPs), utilizing the molecular ruby-type luminophores CrPF6 ([Cr(ddpd)2](PF6)3; ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridin-2,6-diamine) and CrBF4 ([Cr(ddpd)2](BF4)3) with their oxygendependent, but polarity-, proticity-, viscosity-, and concentration-independent luminescence as optical probes for oxygen permeability. The sol–gel chemistry routes we assessed include the classical Stöber method and the underexplored Larginine approach, which relies on the controlled hydrolysis of tetraethoxysilane (TEOS) in a biphasic cyclohexane/water system with the catalyst L-arginine. As demonstrated by luminescence measurements of air- and argon-saturated dispersions of CrPF6- and CrBF4-stained SiO2 NPs of different size and particle architecture, utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF6 and CrBF4 in acetonitrile (ACN) as benchmarks, only SiO2 NPs or shells synthesized by the L-arginine approach provided complete oxygen protection of the CrIII complexes under ambient conditions. We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings, leading to different oxygen permeabilities. Our Larginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future.
KW - Quality assurance
KW - Fluorescence
KW - Quantification
KW - Advanced materials
KW - Nano
KW - Quantum yield
KW - NIR
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Synthesis
KW - Oxygen sensing
KW - Surface
KW - Doping
KW - Lifetime
KW - Cr(III) complex
KW - Shielding
KW - Sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638271
DO - https://doi.org/10.26599/NR.2025.94907241
SN - 1998-0000
VL - 18
IS - 3
SP - 1
EP - 13
PB - SciOpen
AN - OPUS4-63827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yu, Z.
A1 - Musnier, B.
A1 - Wegner, Karl David
A1 - Henry, M.
A1 - Chovelon, B.
A1 - Desroches-Castan, A.
A1 - Fertin, A.
A1 - Resch-Genger, Ute
A1 - Bailly, S.
A1 - Coll, J.-L.
A1 - Usson, Y,
A1 - Josserand, V.
A1 - Le Gúevel, X.
T1 - High-Resolution Shortwave Infrared Imaging of Vascular Disorders Using Gold Nanoclusters
N2 - We synthesized a generation of water-soluble, atomically precise gold nanoclusters (Au NCs) with anisotropic Surface containing a short dithiol pegylated chain (AuMHA/TDT). The AuMHA/TDT exhibit a high brightness (QY ∼ 6%) in the shortwave infrared (SWIR) spectrum with a detection above 1250 nm.
Furthermore, they show an extended half-life in blood (t1/2ß = 19.54 ± 0.05 h) and a very weak accumulation in organs. We also developed a non-invasive, whole-body vascular imaging system in the SWIR window with high-resolution, benefiting from a series of Monte Carlo image processing. The imaging process enabled to improve contrast by 1 order of magnitude and enhance the spatial Resolution by 59%. After systemic administration of these nanoprobes in mice, we can quantify vessel complexity in depth (>4 mm), allowing to detect very subtle vascular disorders non-invasively in bone morphogenetic protein 9 (Bmp9)-deficient mice. The combination of these anisotropic surface charged Au NCs plus an improved SWIR imaging device allows a precise mapping at high-resolution and an in depth understanding of the organization of the vascular network in live animals.
KW - Nanoparticle
KW - Nanosensor
KW - Fluorescence
KW - Metal cluster
KW - NIR
KW - SWIR
KW - Photophysics
KW - Ligand
KW - Size
KW - Surface chemistry
KW - Quantum yield
KW - Mechanism
KW - Lifetime
KW - Decay kinetics
PY - 2020
DO - https://doi.org/10.1021/acsnano.0c01174
VL - 14
IS - 4
SP - 4973
EP - 4981
PB - ACS Publication
AN - OPUS4-50671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Reliable measurements of the photoluminescence quantum yield of transparent and scattering luminophores
N2 - Optical measurements of transparent solutions of organic dyes and semiconductor quantum dots and scattering materials such as luminescent nanocomposites and microparticles and phosphors dispersed in liquid and solid matrices play an important role in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. A key performance parameter is the photoluminescence quantum yield QY, i.e., the number of emitted per number of absorbed photons. QY of transparent luminophore solutions can be obtained relative to a fluorescence QY standard of known QY.[1] Meanwhile, a first set of certified fluorescence QY standards is available.[2] Such relative QY measurements require a calibrated spectrofluorometer.[1,3] For determining QY of scattering liquid and solid samples, absolute measurements of QY with a calibrated integrating sphere setup are mandatory.[1,4,5] However, scattering QY standards are not available and uncertainties of such measurements have not yet been assessed in interlaboratory comparisons (ILCs).
To determine typical sources of uncertainty of absolute QY measurements, we assessed the influence of the measurement geometry and the optical properties of the blank for determining the number of incident photons absorbed by the sample in an ILC using commercial integrating sphere setups and a custom-designed integrating sphere setup. Samples examined included transparent and scattering dye solutions, solid phosphors such as YAG:Ce optoceramics used as LED converter material, and polymer films stained with different amounts of phosphor microparticles. Matching QY values could be obtained for transparent dye solutions and scattering dispersions with a blank with scattering properties closely matching those of the sample, while QY measurements of optoceramic samples with different blanks revealed substantial differences of more than 20 %. Based on our data, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder as blanks.
T2 - eMRS 2025 Fall Meeting
CY - Warsaw, Poland
DA - 15.09.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Advanced material
KW - Synthesis
KW - Characterization
KW - Fluorescence quantum yield
KW - Phosphor
KW - Absolute
KW - Integrating sphere spectroscopy
KW - Dye
KW - Standardization
KW - Reference material
KW - Interlaboratory comparison
KW - Uncertainty
PY - 2025
AN - OPUS4-64184
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Z.
A1 - Wegner, Karl David
A1 - Stiegler, L. M. S.
A1 - Zhou, X.
A1 - Rezvani, A.
A1 - Odungat, A. S.
A1 - Zubiri, B. A.
A1 - Wu, M.
A1 - Spiecker, E.
A1 - Walter, J.
A1 - Resch-Genger, Ute
A1 - Segets, D.
T1 - Optimizing the Shelling Process of InP/ZnS Quantum Dots Using a Single-Source Shell Precursor: Implications for Lighting and Display Applications
N2 - InP/ZnS core/shell quantum dots (QDs), recognized as highly promising heavy-metal-free emitters, are increasingly being utilized in lighting and display applications. Their synthesis in a tubular flow reactor enables production in a highly efficient, scalable, and reproducible manner, particularly when combined with a single-source shell precursor, such as zinc diethyldithiocarbamate (Zn(S2CNEt2)2). However, the photoluminescence quantum yield (PLQY) of QDs synthesized with this route remains significantly lower compared with those synthesized in batch reactors involving multiple steps for the shell growth. Our study identifies the formation of absorbing, yet nonemissive ZnS nanoparticles during the ZnS shell formation process as a main contributing factor to this discrepancy. By varying the shelling conditions, especially the shelling reaction temperature and InP core concentration, we investigated the formation of pure ZnS nanoparticles and their impact on the optical properties, particularly PLQY, of the resultant InP/ZnS QDs through ultraviolet−visible (UV−vis) absorption, steady-state and time-resolved photoluminescence (PL) spectroscopy, scanning transmission electron microscopy (STEM), and analytical ultracentrifugation (AUC) measurements. Our results suggest that process conditions, such as lower shelling temperatures or reduced InP core concentrations (resulting in a lower external surface area), encourage homogeneous nucleation of ZnS. This reduces the availability of shell precursors necessary for effective passivation of the InP core surfaces, ultimately resulting in lower PLQYs. These findings explain the origin of persistently underperforming PLQY of InP/ZnS QDs synthesized from this synthesis route and suggest further optimization strategies to improve their emission for lighting and display applications.
KW - Nano
KW - Particle
KW - Synthesis
KW - InP
KW - Shell
KW - Fluorescence
KW - Quantum yield
KW - ZnS
KW - Semiconductor
KW - Quantum dot
KW - Flow reactor
KW - Method
KW - AUC
KW - Size
KW - Automation
KW - Sensor
PY - 2024
DO - https://doi.org/10.1021/acsanm.4c05265
SN - 2574-0970
VL - 7
IS - 20
SP - 24262
EP - 24273
PB - ACS Publications
AN - OPUS4-61518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Soyka, J. P.
A1 - Witte, J. F.
A1 - Wiesner, A.
A1 - Krappe, A. R.
A1 - Wehner, D.
A1 - Alnicola, N.
A1 - Paulus, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - [3]Radialene Fluorophores with pH-Switchable Emission and Stable Absorption Maxima
N2 - The first push–pull quino [3]radialene fluorescent dye is reported. Herein, the novel bis(dicyanomethylene)-[3]radialene electron acceptor is connected to a benzimidazole donor. With protonation, a substantial redshift of fluorescence wavelength is observed, while the absorption maximum remains stable. This process is accompanied with an increased fluorescence quantum yield to about 70%. Further, the findings are explained by a combined experimental and theoretical approach, and it is found that vibronic coupling plays a crucial role. This study highlights the yet unexplored potential of [3]radialene-based motifs for the design of environment-responsive fluorophores.
KW - DADQ
KW - Nanographene
KW - fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Quantum yield
KW - Photophysic
KW - pH
KW - Probe
KW - Sensor
KW - Lifetime
KW - Polarity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642147
DO - https://doi.org/10.1002/ejoc.202500669
SN - 1099-0690
SP - 1
EP - 6
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64214
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amouroux, B.
A1 - Würth, Christian
A1 - Roux, C.
A1 - Eftekhari, A.
A1 - Sliwa, M.
A1 - Bouchet, A.
A1 - Micheau, J.-C.
A1 - Resch-Genger, Ute
A1 - Coudret, C.
T1 - Time-Resolved Rate Equation Analysis Disclose Kinetics Controlling Luminescence of Nanometer Tm-Upconverting Nanoparticles
N2 - Upconversion luminescence of lanthanide-based upconversion nanoparticles (UCNPs) is a nonlinear step-wise process in which the consecutive absorption of multiple, low-energy photons results in the subsequent emission of a high-energy photon. The primary upconversion mechanism is energy transfer upconversion (ETU) from a sensitizer (Yb3+) to an activator (Tm3+). It requires the absorption of several excitation lowenergy photons by Yb3+, followed by the sequential energy transfer to Tm3+ions. Excited states relax to their ground states either radiatively by emitting a high-energy photon or non-radiatively by multiphonon relaxation through the crystalline host matrix. The time-resolved rise and decay luminescence curves of a set of five ultrasmall have been recorded under varying power near-infrared μs pulses. Six wavelengths have been used to monitor the evolution of the main Yb and Tm excited states. We use an average rate equations model to decipher the relationships between the compositional constraints and size of these ultrasmall UCNPs and the luminescence kinetic parameters. Several rate constants of ETU and other depopulation processes involving the multiple states of the Tm3+ energy scaffold have been retrieved from the simultaneous fit of the recorded curves. Their values have been interpreted by considering bulk and surface quenching, radiative and multi-phonon relaxations, and ion-to-ion hopping. Energy transfer between Yb3+ and Tm3+ is mainly occurring within neighbor atoms. The importance of mismatches on multiphonon relaxations, ETUs, and back-transfers has also been highlighted. For these numerical modeling, it appears that changing the composition and synthesis conditions with the aim to improve a single-specific parameter could remain a major challenge as this modification would automatically impact other properties with immediate consequences on UCNP dynamics.
KW - Nano
KW - Particle
KW - Synthesis
KW - Shell
KW - Fluorescence
KW - Lifetime
KW - Decay kinetics
KW - Method
KW - Modelling
KW - Quality assurance
KW - Energy transfer
KW - Upconversation
PY - 2024
DO - https://doi.org/10.1021/acs.jpcc.4c04969
VL - 128
IS - 44
SP - 18836
EP - 18848
PB - ACS Publications
AN - OPUS4-61645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, T.
A1 - Wang, J.
A1 - Cheng, Z.
A1 - Liu, Y.
A1 - Qiao, X.
A1 - Wen, J.
A1 - Resch-Genger, Ute
A1 - Long, W.
A1 - Ou, J.
T1 - NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ Upconversion Nanoparticles for Optical Temperature Monitoring and Self-Heating in Photothermal Therapy
N2 - The core−shell NaYF4:Yb3+/Tm3+@NaYF4:Yb3+ upconversion nanoparticles were successfully prepared by a solvothermal method, and a layer of mesoporous silica (mSiO2) was successfully coated on the periphery of the core−shell nanoparticles to transform their surface from lipophilic to hydrophilic, further expanding their applications in biological tissues. The physical phase, morphology, structure, and fluorescence properties were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (TEM), Fourier infrared spectroscopy (FT-IR), ζ potential analysis, and fluorescence spectroscopy. It was found that the material has a hexagonal structure with good hydrophilicity and emits intense fluorescence under 980 nm pump laser excitation. The non-contact temperature sensing performance of nanoparticles was evaluated by analyzing the upconversion fluorescence of Tm3+ (1G4 → 3F4 and 3F3 → 3H6) in the temperature range of 284−344 K. The absolute and relative sensitivities were found to be 0.0067 K−1 and 1.08 % K−1, respectively, with high-temperature measurement reliability and good temperature cycling performance. More importantly, its temperature measurement in phosphate-buffered saline (PBS) solution is accurate. In addition, the temperature of the cells can be increased by adjusting the laser power density and laser irradiation time. Therefore, an optical temperature sensing platform was built to realize the application of real-time monitoring of cancer cell temperature and the dual function of photothermal therapy.
KW - Sensor
KW - Temperature
KW - Lanthanide
KW - Tag
KW - Fluorescence
KW - Nanoparticles
KW - Synthesis
KW - Environment
KW - Monitoring
KW - Sensing
KW - Nano
KW - Life sciences
KW - Upconversion
PY - 2023
DO - https://doi.org/10.1021/acsanm.2c05110
VL - 6
IS - 1
SP - 759
EP - 771
PB - ACS Publications
AN - OPUS4-57081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, T.
A1 - Wang, J.
A1 - Cheng, Z.
A1 - Li, Z.
A1 - Qiao, X.
A1 - Wen, J.
A1 - Resch-Genger, Ute
A1 - Long, W.
A1 - Ou, Jun
T1 - Preparation of NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles and application of their fluorescence temperature sensing properties
N2 - The NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles were successfully prepared by the solvothermal method, and the samples were pure hexagonal phase with good crystallinity and homogeneous size, asevidenced by XRD and TEM analysis. The FT-IR analysis shows that β-CD is successfully encapsulated on the surface of NaYF4: Yb3+/Tm3+@NaYF4 nanoparticles. The fluorescence intensity 3and lifetime were significantly increased after coating the inert layer on the surface of core nanoparticles. After further surface modification of β-CD, the fluorescence intensity and fluorescence lifetime were reduced, but the overall fluorescence was stronger. Temperature measurements using the fluorescence intensity ratio technique were found to have relatively low reliability and absolute sensitivity for temperature measurements using thermally coupled energy levels. However, the reliability of temperature measurements using non-thermally coupled energy levels is significantly higher and the absolute sensitivity is much higher than for measurements at thermally coupled levels. Since the maximum absolute sensitivity, maximum relative sensitivity and minimum temperature resolution are determined to be 0.1179 K-1, 2.19 %K 1 and 0.00019 K, respectively, NaYF4: Yb3+/Tm3+@NaYF4@β-CD upconversion nanoparticles are expected to be widely used in the biomedical field due to their feasibility, reliability, non-toxicity and harmlessness.
KW - Upconversion
KW - Surface modification
KW - Fluorescence intensity ratio
KW - Thermally coupled levels
KW - Non-thermally coupled levels
PY - 2023
DO - https://doi.org/10.1016/j.optmat.2022.113389
SN - 0925-3467
VL - 136
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-57105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Tavernaro, Isabella
A1 - Abram, Sarah-Luise
A1 - Andresen, Elina
A1 - Matiushkina, Anna
T1 - Quantifying the number of total and accessible functional groups on nanomaterials
N2 - Inorganic and organic functional nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are relevant for many key technologies of the 21st century. Decisive for most applications of NM are their specific surface properties, which are largely controlled by the chemical nature and number of ligands and functional groups (FG on the NM surface. The surface chemistry can strongly affect the physicochemical properties of NM, their charge, hydrophilicity/hydrophobicity, reactivity, stability, and processability and thereby their impact on the environment and biological species as well as their possible risk for human health. Thus, reliable, validated, and eventually standardized analytical methods for the characterization of NM surface chemistry, i.e., the chemical identification, quantification, and accessibility of FG and surface ligands 1,2] flanked by interlaboratory comparisons, control samples, and reference materials, 2 ,3 are of considerable importance for process and quality control of NM production and function. This is also important for the safe use of NM the design of novel NM, and sustainable concepts for NM fabrication. Here, we provide an overview of analytical methods for FG analysis and quantification and highlight method and material related challenges for selected NM. Analytical techniques address ed include electrochemical titration methods, optical assays, nuclear magnetic resonance (NMR) and vibrational (IR) spectroscopy, and X ray based and thermal analysis methods. Criteria for method classification and evaluation include the need for a signal generating label, provision of either the total or derivatizable number of FG, and suitability for process and production control.
T2 - AUC - Analytical Ultracentrifugation
CY - Nuremberg, Germany
DA - 22.07.2024
KW - Nanoparticle
KW - Particle
KW - Microparticle
KW - Silica
KW - Quantum dot
KW - Polymer
KW - Surface group
KW - Luminescence
KW - Quality assurance
KW - Synthesis
KW - Surface modification
KW - ILC
KW - Optical assay
KW - Functional group
KW - Ligand
KW - qNMR
KW - Conductometry
KW - Potentiometry
KW - Standardization
KW - Reference product
KW - Reference material
PY - 2024
AN - OPUS4-60749
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auxillos, J.
A1 - Crouigneau, R.
A1 - Li, Y.-F.
A1 - Dai, Y.
A1 - Stigliani, A.
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Sandelin, A.
A1 - Marie, R.
A1 - Pedersen, S. F.
T1 - Spatially resolved analysis of microenvironmental gradient impact on cancer cell phenotypes
N2 - Despite the physiological and pathophysiological significance of microenvironmental gradients, e.g., for diseases such as cancer, tools for generating such gradients and analyzing their impact are lacking. Here, we present an integrated microfluidic-based workflow that mimics extracellular pH gradients characteristic of solid tumors while enabling high-resolution live imaging of, e.g., cell motility and chemotaxis, and preserving the capacity to capture the spatial transcriptome. Our microfluidic device generates a pH gradient that can be rapidly controlled to mimic spatiotemporal microenvironmental changes over cancer cells embedded in a 3D matrix. The device can be reopened allowing immunofluorescence analysis of selected phenotypes, as well as the transfer of cells and matrix to a Visium slide for spatially resolved analysis of transcriptional changes across the pH gradient. This workflow is easily adaptable to other gradients and multiple cell types and can therefore prove invaluable for integrated analysis of roles of microenvironmental gradients in biology.
KW - Bioimaging
KW - Fluorescence
KW - Cell
KW - Cancer
KW - Method
KW - Microfluids
KW - Model
KW - Calibration
KW - Sensor
KW - Ph
KW - Probe
KW - Workflow
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604631
DO - https://doi.org/10.1126/sciadv.adn3448
VL - 19
IS - 18
SP - 1
EP - 17
AN - OPUS4-60463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oskoei, P.
A1 - Nogueira, J.
A1 - Keller, Lisa-Marie
A1 - Andresen, Elina
A1 - Maturi, F. E.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Daniel-da-Silva, A. L.
A1 - Carlos, L. D.
A1 - Oliviera, H.
T1 - Effects of doxorubicin-loaded UCNP@MSN core-shell particles with a thermoresponsive nanovalve in melanoma cells
N2 - Melanoma, one of the most aggressive forms of skin cancer, has an increasingly higher incidence. When detected in advanced stages, tumour eradication is often incomplete, contributing to poor prognosis with conventional treatments. Upconversion nanoparticles (UCNPs) haveunique optical properties that allow their effective use in several biomedical applications. This includes the excitability under near-infrared (NIR) excitation light, which has a relatively high penetration depth in tissue, a multitude of characteristic emission bands in the ultraviolet (UV), visible (Vis), NIR, and short-wave infrared (SWIR), along with long luminescence lifetimes, and high photostability. Mesoporous silica nanoparticles (MSN) with nanovalves or derived coatings have widely been used for triggered and targeted drug delivery in the past. Anticancer drugs can be loaded into the pores of MSN, enabling spatiotemporally controlled drug release.
KW - Nano
KW - Particle
KW - Silica
KW - Upconversation
KW - Lanthanide
KW - Triggered release
KW - Temperature
KW - Cell studies
KW - Drug
KW - Toxicity studies
PY - 2024
DO - https://doi.org/10.1016/j.toxlet.2024.07.237
SN - 0378-4274
VL - 399
IS - Supplement 2
SP - S89
EP - S90
PB - Elsevier B.V.
AN - OPUS4-62571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amouroux, B.
A1 - Eftekhari, A.
A1 - Roux, C.
A1 - Micheau, J.
A1 - Roblin, P.
A1 - Pasturel, M.
A1 - Gauffre, F.
A1 - Würth, Christian
A1 - Resch-Genger, Ute
A1 - Sliwa, M.
A1 - Bouchet, A.
A1 - Coudret, C.
T1 - Synthesis and Emission Dynamics of Sub-3 nm Upconversion Nanoparticles
N2 - Reducing the size of upconversion nanoparticles (UCNPs) down to a few nm yields luminescent materials containing a very small number of emitters.
Considering the bottom limit of one activator per particle ultrasmall UCNPs offer an unprecedented platform to study the contributions of the energy transfers at play in upconversion luminescence. Maintaining detectable emission despite the limited number of emitting ions and the high surface-to-volume ratio requires suitable particle architectures.
Na(Gd-Yb)F4:Tm3+ emissive sub-3 nm diameter 𝜷-phase UCNPs are prepared using a gadolinium-rich composition in situ mixing of the precursors and a microwave high-temperature cycling sequence allowing precise control of the particle size and dispersity. These cores are coated with a NaGdF4 inert shell to minimize the deleterious influence of surface quenching (SQ).
Time-resolved luminescence measurements combining standard NIR excitation of the Yb3+ sensitizer and direct UV excitation of the Tm3+ activator are performed to quantify cross relaxation and surface quenching processes.
The fine tuning of the number of activators per particle via an optimized synthesis pathway along with the use of an appropriate excitation scheme enabled to provide an accurate analysis of the different mechanisms at play in these model nanoparticles and to characterize the structure of the core-shell architecture.
KW - Lanthanide
KW - Nanoparticle
KW - Luminescence
KW - Quantitative spectroscopy
KW - Quantum yield
KW - Energy transfer
KW - Quality assurance
KW - Synthesis
KW - Surface modification
KW - Photophysics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606877
DO - https://doi.org/10.1002/adom.202303283
SN - 2195-1071
SP - 1
EP - 13
AN - OPUS4-60687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nirmalananthan-Budau, Nithiya
A1 - Budau, J. H.
A1 - Moldenhauer, Daniel
A1 - Hermann, G.
A1 - Kraus, Werner
A1 - Hoffmann, Katrin
A1 - Paulus, Beate
A1 - Resch-Genger, Ute
T1 - Substitution pattern controlled aggregation-induced emission in donor-acceptor-donor dyes with one and two propeller-like triphenylamine donors
N2 - We present a comparative study of the spectroscopic properties of the donor–acceptor–donor substituted dyes triphenylamine-allylidenemalononitrile-julolidine (TMJ) and triphenylamine-allylidenemalononitriletriphenylamine (TMT), bearing one and two propeller-like triphenylamine donor moieties, in solvents of varying polarity and viscosity and in the aggregated and solid state. Our results reveal control of the aggregation-induced spectroscopic changes and the packing motifs of the dye molecules in the solid state by the chemical nature and structure of the second nitrogen-containing donor, i.e., a planar and a rigid julolidine or a twisted triphenyl group. Assuming that the TMT and TMJ aggregates show a comparable arrangement of the molecules to the respective crystals, these different molecular interactions in the solid state are responsible for aggregation induced emission (AIE) in the case of TMT and its absence for TMJ. Moreover, a versatile strategy for the fluorescence enhancement of only weakly emissive AIE dyes is shown, turning these dyes into bright nanoscale fluorescent reporters by using them as stains for preformed polymer particles.
KW - Nano
KW - Nanoparticle
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Dye
KW - Enhancement
KW - Particle
KW - Polarity
KW - AIE
KW - Aggregation
KW - Aggregation-induced emission
KW - Solid state emission
PY - 2020
DO - https://doi.org/10.1039/d0cp00413h
VL - 22
IS - 25
SP - 14142
EP - 14154
AN - OPUS4-50967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stroyuk, O.
A1 - Raievska, O.
A1 - Barabash, A.
A1 - Batentschuk, M.
A1 - Osvet, A.
A1 - Fiedler, Saskia
A1 - Resch-Genger, Ute
A1 - Hauch, J.
A1 - Brabec, C. J.
T1 - "Green" synthesis of highly luminescent lead-free Cs2AgxNa1-xBiyIn1-yCl6 perovskites
N2 - A new “green” and mild synthesis of highly stable microcrystalline Cs2AgxNa1-xBiyIn1-yCl6 (CANBIC) perovskites under ambient conditions was developed that is scalable to the multi-gram production. Under UV illumination, the CANBIC perovskites emit intense broadband photoluminescence (PL) with a quantum yield (QY) of 92% observed for x = 0.35 and y = 0.01-0.02. The combination of strong UV absorbance and broadband visible emission, high PL QY, and long PL lifetimes of up to 1.4 μs, along with an outstanding stability makes these CANBICs a promising material class for many optical applications.
KW - Fluorescence
KW - Perovskites
KW - Solar cell
KW - Automated synthesis
KW - Green synthesis
KW - Quantum yield
KW - Integrating sphere spectroscopy
KW - Absolute fluorescence
KW - Quality assurance
KW - Nano
KW - Particle
KW - Application
KW - Semiconductor
KW - Quantum dot
KW - Renewable energy
PY - 2022
DO - https://doi.org/10.1039/d2tc02055f
SN - 2050-7526
VL - 10
IS - 27
SP - 9938
EP - 9944
PB - Royal Society of Chemistry
AN - OPUS4-55453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Nirmalananthan-Budau, Nithiya
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
T1 - Analyzing the surface of functional nanomaterials — how to quantify the total and derivatizable number of functional groups and ligands
N2 - Functional nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are of increasing relevance for many key technologies of the twenty-first century. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide-based NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. The surface chemistry can significantly affect the physicochemical properties of NM, their charge, their processability and performance, as well as their impact on human health and the environment. Thus, analytical methods for the characterization of NM surface chemistry regarding chemical identification, quantification, and accessibility of functional groups (FG) and surface ligands bearing such FG are of increasing importance for quality control of NM synthesis up to nanosafety. Here, we provide an overview of analytical methods for FG analysis and quantification with special emphasis on bioanalytically relevant FG broadly utilized for the covalent attachment of biomolecules like proteins, peptides, and oligonucleotides and address methodand material-related challenges and limitations. Analytical techniques reviewed include electrochemical titration methods, optical assays, nuclear magnetic resonance and vibrational spectroscopy, as well as X-ray based and thermal analysis methods, covering the last 5–10 years. Criteria for method classification and evaluation include the need for a signal-generating label, provision of either the total or derivatizable number of FG, need for expensive instrumentation, and suitability for process and production control during NM synthesis and functionalization.
KW - Functional group quantification
KW - Surface ligand
KW - Nanomaterial
KW - Optical detection
KW - Electrochemical titration
KW - Nanosafety (Safe-by-design)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533597
DO - https://doi.org/10.1007/s00604-021-04960-5
VL - 188
IS - 10
SP - 1
EP - 28
PB - Springer Nature
AN - OPUS4-53359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Cui
A1 - Kitzmann, W.R.
A1 - Weigert, Florian
A1 - Förster, Ch.
A1 - Wang, X.
A1 - Heintze, K.
A1 - Resch-Genger, Ute
T1 - Matrix Effects on Photoluminescence and Oxygen Sensitivity of a Molecular Ruby
N2 - The molecular ruby analogue [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) exhibits near infrared (NIR) emission with a high photoluminescence (PL) quantum yield ΦPL of 11 % and a lifetime of 898 μs in deaerated water at room temperature. While ligand-based control of the photophysical properties has received much attention, influences of the counter anions and microenvironment are still underexplored. In this study, the luminescence properties of the molecular ruby were systematically examined for the counter anions Cl−, Br−, [BF4]−, [PF6]−, [BPh4]−, and [BArF24]− in acetonitrile (MeCN) solution, in crystals, and embedded into polystyrene nanoparticles (PSNP). Stern-Volmer analyses of the oxygen quenching studies in the intensity and lifetime domain showed the highest oxygen sensitivity of the complexes with the counter anions of [BF4]− and [BArF24]−, which also revealed the longest luminescence lifetimes. Embedding [Cr(ddpd)2][PF6]3 in PSNPs and shielding with poly(vinyl alcohol) yields a strongly NIR-emissive oxygen-insensitive material with a record ΦPL of 15.2 % under ambient conditions.
KW - Fluorescence
KW - Sensor
KW - Oxygen
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Solid state
KW - X-Ray analysis
KW - Structure-property relationship
KW - Nano
KW - Polymer
KW - Particle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546057
DO - https://doi.org/10.1002/cptc.202100296
SN - 2367-0932
VL - 6
IS - 6
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, C.
A1 - Schäferling, Michael
A1 - Resch-Genger, Ute
A1 - Gradzielski, M.
T1 - Solvothermal Synthesis of Lanthanide-doped NaYF4 Upconversion
N2 - Lanthanide-doped NaYF4 upconversion nano- and microcrystals were synthesized via a facile solvothermal approach. Thereby, the influence of volume ratios of ethylene glycol (EG)/H2O, molar ratios of NH4F/RE3+ (RE3+ represents the total amount of Y3+ and rare-earth dopant ions), Gd3+ ion contents, types of activator dopant ions, and different organic co-solvents on the crystal phase, size, and morphology of the resulting particles were studied systematically. A possible formation mechanism for the growth of crystals of different morphology is discussed. Our results show that the transition from the α- to the β-phase mainly depends on the volume ratio of EG/H2O and the molar ratio of NH4F/RE3+, while the morphology and size could be controlled by the type of organic co-solvent and Gd3+ dopant ions. Furthermore, the reaction time has to be long enough to convert α-NaYF4 into β-NaYF4 during the growth process to optimize the upconversion luminescence. The formation of larger β-NaYF4 crystals, which possess a higher upconversion luminescence than smaller particles, proceeds via intermediates of smaller crystals of cubic structure. In summary, our synthetic approach presents a facile route to tailor the size, Crystal phase, morphology, and luminescence features of upconversion
materials.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Photoluminescence
KW - Lanthanide
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Surface chemistry
KW - Single particle
KW - Brightness
KW - NIR
KW - Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520307
DO - https://doi.org/10.1002/cnma.202000564
VL - 7
IS - 2
SP - 174
EP - 183
PB - Wiley
AN - OPUS4-52030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bastos, V.
A1 - Oskoei, P.
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Oliveira, H.
T1 - Stability, dissolution, and cytotoxicity of NaYF4‑upconversion nanoparticles with different coatings
N2 - Upconversion nanoparticles (UCNPs) have attracted considerable attention owing to their unique photophysical properties. Their utilization in biomedical applications depends on the understanding of their transformations under physiological conditions and their potential toxicity. In this study, NaYF4: Yb,Er UCNPs, widely used for luminescence and photophysical studies, were modified with a set of four different coordinatively bound surface ligands, i.e., citrate, alendronate (AA), ethylendiamine tetra(methylene phosphonate) (EDTMP), and poly(maleic anhydride-alt-1-octadecene) (PMAO), as well as silica coatings with two different thicknesses. Subsequently, the aging-induced release of fluoride ions in water and cell culture media and their cytotoxic profile to human keratinocytes were assessed in parallel to the cytotoxic evaluation of the ligands, sodium fluoride and the lanthanide ions. The cytotoxicity studies of UCNPs with different surface modifications demonstrated the good biocompatibility of EDTMP-UCNPs and PMAO-UCNPs, which is in line with the low amount of fluoride ions released from these samples. An efficient prevention of UCNP dissolution and release of cytotoxic ions, as well as low cytotoxicity was also observed for UCNPs with a sufficiently thick silica shell. Overall, our results provide new insights into the
understanding of the contribution of surface chemistry to the stability, dissolution behavior, and cytotoxicity of UCNPs. Altogether, the results obtained are highly important for future applications of UCNPs in the life sciences and bioimaging studies.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Excitation power density
KW - Surface chemistry
KW - Coating
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544681
DO - https://doi.org/10.1038/s41598-022-07630-5
SN - 2045-2322
VL - 12
SP - 1
EP - 13
PB - Springer Nature
CY - London
AN - OPUS4-54468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, F.
A1 - Rietsch, P.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Weigert, Florian
A1 - Götze, J. P.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
A1 - Paulus, B.
T1 - Aggregation-induced emission leading to two distinct emissive species in the solid-state structure of high-dipole organic chromophores
N2 - The concept of aggregation-induced emission represents a means to rationalise photoluminescence of usually nonfluorescent excimers in solid-state materials. In this publication, we study the photophysical properties of selected diaminodicyanoquinone (DADQ) derivatives in the solid state using a combined approach of experiment and theory. DADQs are a class of high-dipole organic chromophores promising for applications in non-linear optics and light-harvesting devices. Among the compounds investigated, we find both aggregation-induced emission and aggregation-caused quenching effects rationalised by calculated energy transfer rates. Analysis of fluorescence spectra and lifetime measurements provide the interesting result that (at least) two emissive species seem to contribute to the photophysical properties of DADQs. The main emission peak is notably broadened in the long-wavelength limit and exhibits a blue-shifted shoulder. We employ high-level quantum-chemical methods to validate a molecular approach to a solid-state problem and show that the complex emission features of DADQs can be attributed to a combination of H-type aggregates, monomers, and crystal structure defects.
KW - Fluorescence
KW - Optical probe
KW - Dye
KW - Photophysics
KW - Theory
KW - Quantum yield
KW - Mechanism
KW - Quantum chemistry
KW - Modelling
KW - Aggregation
KW - Lifetime
KW - Single particle
KW - Microscopy
KW - Solid
KW - Crystal
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531138
DO - https://doi.org/10.1039/d1cp02534a
SP - 1
EP - 9
PB - Royal Society of Chemistry
AN - OPUS4-53113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le Guevel, X.
A1 - Wegner, Karl David
A1 - Würth, Christian
A1 - Baulin, V. A.
A1 - Musnier, B.
A1 - Josserand, V.
A1 - Resch-Genger, Ute
A1 - Koll, J-C
T1 - Tailoring the SWIR emission of gold nanoclusters by surface ligand rigidification and their application in 3D bioimaging
N2 - The influence of solvent polarity and surface ligand rigidification on the SWIR emission profile of gold nanoclusters with an anistropic surface was investigated. A strong enhancement of the SWIR emission band at 1200 nm was observed when measuring in different local environments: in solution, in polymer composites, and in solids. SWIR in vivo imaging of mice assisted by deep learning after intravenous administration of these gold nanoclusters provides high definition pseudo-3D views of vascular blood vessels.
KW - Nano
KW - Nanomaterial
KW - Metal cluster
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - SWIR
KW - Ligand
KW - Gold
KW - Mechanism
KW - Charge transfer
KW - Enhancement strategy
KW - Imaging
KW - Application
KW - Contrast agent
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543582
DO - https://doi.org/10.1039/D1CC06737K
VL - 58
IS - 18
SP - 2967
EP - 2970
PB - RSC
AN - OPUS4-54358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Mohring, Wencke
A1 - Schneider, Mike
A1 - Laplanche, Guillaume
A1 - Hagen, Sebastian Peter
A1 - Stephan‐Scherb, Christiane
T1 - High‐Temperature Oxidation of the CrFeNi Medium‐Entropy Alloy
N2 - The isothermal high‐temperature oxidation behavior of the equiatomic CrFeNi medium‐entropy alloy is a key issue that determines whether this material is suited for high‐temperature application. In this view, the understanding of the long‐term behavior is even more crucial than short‐term corrosion effects. Herein, a single‐phase CrFeNi alloy of the face‐centered‐cubic structure is exposed to synthetic air at 1000, 1050, and 1100 °C for 24, 100, and 1000 h and its oxidation behavior is systematically compared to that of 316L steel, which shows a surprising initial oxidation stabilization during early stages. The oxidation rate of CrFeNi is parabolic at 1000 °C (with a parabolic constant kp = 1.4·10−5 mg−2 cm−4 s−1) and 1050 °C (kp = 2.7·10−5 mg−2 cm−4 s−1), but breakaway oxidation occurs at 1100 °C after 4 h of exposure. In all cases, the oxide scales are found to (at least) partially spall off. Chromium diffuses outward to form a Cr2O3 layer at the gas/oxide interface, and a thin layer of (Cr, Fe, Ni)3O4 is identified at the oxide/alloy interface. Unlike the 316L alloy, which contains more Mn and Fe, the CrFeNi alloy does not show any catastrophic oxidation behavior at the investigated conditions.
KW - Corrosion
KW - Medium-entropy alloy
KW - Scanning electron microscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636672
DO - https://doi.org/10.1002/adem.202500400
SN - 1438-1656
SP - 1
EP - 14
PB - Wiley VHC-Verlag
AN - OPUS4-63667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Agudo Jácome, Leonardo
A1 - Thompsom, Sean
A1 - Schneider, Judy
T1 - On the transferability of post-processing heat treatments designed for PBF-LB IN718 alloys to directed energy deposition specimens
N2 - Many processes are being developed for metal additive manufacturing (AM) which vary by their heat source and feedstock. The use of directed energy deposition (DED) is growing due to its ability to build larger structures outside of a contained powder bed chamber. However, the only standard exclusively for post-build heat treatment of AM IN718 is ASTM standard F3055-14a, developed for powder bed fusion (PBF). This study evaluates the applicability of this current heat treatment standard to AM IN718 specimens produced using two methods of DED: laser-blown powder (LP)-DED and arc-wire (AW)-DED. Electron microscopy and X-ray diffraction techniques were used to characterize the specimens in the as-built condition and after the full heat treatment (FHT) specified in F3055. No evidence of remaining Laves phase was observed in the two DED specimens after the FHT. Yield strengths for the DED specimens were 1049 MPa for FHT AW-DED and 1096 MPa for LP-DED, higher than the minimum stated for PBF-LB IN718 of 920 MPa. The size, morphology, inter-spacing, and diffraction patterns of the γ´ and γ´´ strengthening precipitates are found to be similar for both DED processes. Differences were observed in the microstructure evolution where the F3055 heat treatments resulted in partial recrystallization of the grain structure, with a higher content of annealing twins observed in the AW-DED. These microstructural differences correlate with differences in the resulting elongation to failure. Thus, it is proposed that variations in heat treatments are needed for optimizing IN718 produced by different AM processes.
KW - Additive manufacturing variants
KW - Directed energy deposition (DED)
KW - Post-process heat treatments
KW - SEM-EBSD and TEM microscopy
KW - XRD phase analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628165
DO - https://doi.org/10.1007/s00170-025-15386-1
SN - 1433-3015
VL - 137
IS - 7-8
SP - 3949
EP - 3965
PB - Springer Science and Business Media LLC
AN - OPUS4-62816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weinel, Kristina
A1 - Hahn, Marc Benjamin
A1 - Lubk, Axel
A1 - González Martínez, Ignacio Guillermo
A1 - Büchner, Bernd
A1 - Agudo Jácome, Leonardo
T1 - Nanoparticle Synthesis by Precursor Irradiation with Low-Energy Electrons
N2 - Nanoparticles (NPs) and their fabrication routes are intensely studied for their wide range of application in optics, chemistry, and medicine. Γ-ray and ion irradiation of precursor matter are established methods that facilitate tailored NP synthesis without complicated chemistry. Here, we develop and explore NP synthesis based on irradiating precursor microparticles with low-energy electron beams. We specifically demonstrate the fabrication of plasmonic gold nanoparticles of sizes between 3 and 350 nm on an amorphous SiOx substrate using a 30 kV electron beam. By detailed comparison with electron scattering simulations and thermodynamic modeling, we reveal the dominant role of inelastic electron–matter interaction and subsequent localized heating for the observed vaporization of the precursor gold microparticles. This general principle suggests the suitability of electron-beam irradiation for synthesizing NPs of a wide class of materials.
KW - Gold Nanoparticle
KW - Scanning Electron Microscopy
KW - In situ irradiation
KW - Thermodynamic modelling
KW - Heat Transfer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627609
DO - https://doi.org/10.1021/acsanm.4c06033
SN - 2574-0970
VL - 8
IS - 10
SP - 4980
EP - 4988
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-62760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence
N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors.
KW - Fluorescence
KW - BODIPY probe
KW - Molecularly Imprinted Polymers
KW - Sensor Materials
KW - Dyes
KW - Water analysis
KW - Advanced materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629
DO - https://doi.org/10.1039/D3MA00476G
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Verhassel, Alejandra
A1 - Kimani, Martha Wamaitha
A1 - Gidwani, Kamlesh
A1 - Sandholm, Jouko
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Härkönen, Pirkko
T1 - Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles
N2 - Aim: Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with Vicia villosa lectin (VVL)-labeled nanoparticles.
Materials & methods: Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy.
Results: Flow cytometry showed that the binding of VVL-labeled nanoparticles was significantly higher to Tn-antigen-expressing cancer cells than controls. Confocal microscopy demonstrated that particles bound to the cell surface. According to the correlative light and electron microscopy the particles bound mostly as aggregates.
Conclusion: VVL-labeled nanoparticles could provide a new tool for the detection of Tn-antigen-expressing breast and prostate cancer cells.
KW - Breast cancer cells
KW - Fluorescence detection
KW - Lectin labeling
KW - Prostate cancer cells
KW - Silica-coated polystyrene nanoparticles
KW - Tn-antigen
KW - VVL
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613451
DO - https://doi.org/10.1080/17435889.2024.2405454
SN - 1743-5889
VL - 19
SP - 2463
EP - 2478
PB - Taylor & Francis
CY - London
AN - OPUS4-61345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feng, Wen
A1 - Schulz, Johannes
A1 - Wolf, Daniel
A1 - Pylypenko, Sergii
A1 - Gemming, Thomas
A1 - Weinel, Kristina
A1 - Agudo Jácome, Leonardo
A1 - Büchner, Bernd
A1 - Lubk, Axel
T1 - Secondary electron emission from gold microparticles in a transmission electron microscope: comparison of Monte Carlo simulations with experimental results
N2 - We measure the electron beam-induced current to analyze the electron-induced secondary electron (SE) emission from micron-sized gold particles illuminated by 80 and 300 keV electrons in a transmission electron microscope. A direct comparison of the experimental and simulated SE emission (SEE) employing Monte Carlo scattering simulations based on the GEANT4 toolkit yields overall good agreement with a noticeable discrepancy arising from the shortcoming of the GEANT4 scattering cross sections in the low-loss regime. Thus, the electron beam-induced current analysis allows to quantify the inelastic scattering including SEE in the transmission electron microscope and provides further insight into the charging mechanisms.
KW - Electron beam-induced current
KW - Transmission electron microscopy
KW - Secondary electron emission
KW - Secondary electron yield
KW - Gold micronoparticle
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622557
DO - https://doi.org/10.1088/1361-6463/ad9840
VL - 58
IS - 8
SP - 1
EP - 7
PB - IOP Publishing
CY - Bristol, GB
AN - OPUS4-62255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weinel, Kristina
A1 - Schultz, Johannes
A1 - Kalady, Mohammed Fayis
A1 - Wolf, Daniel
A1 - Agudo Jácome, Leonardo
A1 - Lubk, Axel
T1 - Fabrication of 2-dimensional disordered assemblies of gold nanoparticles and investigation of localized surface plasmon resonances
N2 - Interaction of electromagnetic waves, such as electron beams or light, with conductive material can lead to localized surface plasmon resonances (LSPRs) where the incoming energy can be deposited in a collective excitation of electrons of the conduction band, which in turn can result in coherent localized plasmon oscillations. LSPR in metallic nanostructures, such as nanoparticles (NPs), which are sensitive to geometry, material composition and environment, are currently utilized in a wide range of applications, such as surface-enhanced Raman spectroscopy, plasmonic wave guides, improved solar cells, on-chip particle accelerators and nanoantennas. A host of studies that focus on plasmonic NPs ranging from single NPs with several shapes (cubic, spherical, tetrahedral) over 1D assemblies of NPs such as chains, to ordered 2D assemblies of NPs show an increase of the complexity regarding the hybridization behavior of LSPRs eventually lead to delocalized Surface Plasmons. Furthermore, Anderson predicted in 1977 the absence of diffusion or delocalization of waves in disordered systems, which has been discussed as the underlying mechanism for LSPRs localization in disordered metallic thin films and ultrathin 2D networks. Our aim is to further develop these studies on the surface plasmon localization in disordered structures by (1) developing a novel NPs assembly fabrication method that allows fabricating disordered assemblies of NPs of a wide range of NPs sizes, and (2) probing the LSPR with high-resolution electron energy-loss spectroscopy (EELS). Moreover, the dominant dipolar interaction between the NPs, also facilitates an efficient numerical modeling of these systems, which in comparison with the experiments allows for an in-depth study of the impact of various geometric parameters as well as retardation and life-time damping on the observed localization behavior.
To synthesize 2D disordered assemblies of gold NPs on a TEM transparent silicon oxide substrate, a new synthesis routine was developed. This procedure is based on sublimation and redeposition of a gold microparticle precursor induced by an electron beam in a scanning electron microscope (SEM) operated at 30 kV. To characterize the assembly of synthesized NPs in terms of size, shape and spreading over the substrate, TEM measurements were conducted subsequently. To study LSPRs experimentally, EELS in scanning transmission electron microscopy (STEM) mode was carried out. The numerical modelling of LSPRs was performed using a self-consistent dipole model.
The synthesized 2D disordered gold NPs assemblies exhibit a gradient in the NPs mean size, which ranges from 100 nm close to the precursor location down to 2 nm at a distance of more than 20 µm from the precursor location. Additionally, the interparticle distance between the gold NPs increases with increasing distance to the precursor location.
The experimental investigation as well as the numerical simulation of the LSPRs demonstrate a localization behavior that decreases toward larger energies, which is driven by the disorder of the NPs assembly (mainly the random particle distance). That localization behavior stays in contrast to what was found in ultrathin 2D gold networks showing increasing of localization towards higher LSPRs energies. By varying the geometric parameters of the NPs assembly in the simulation, we could identify the NPs thickness as the parameter, that determines the energy-dependence of the localization. Specifically, a critical thickness of approx. 10 nm separates the two localization regimes, which correlates to the energy of the dipole mode resonance crucially depending on the thickness of the NPs.
2D disordered assemblies of gold NPs of a wide range of NPs sizes and distances can be synthesized directly on thin substrates facilitating structural characterization and EELS measurements in a TEM. It could be shown that such assemblies exhibit LSPRs with a localization behavior that may be tuned by the NPs sizes (including thickness) and interparticle distances. The proposed synthesis of random NPs assemblies opens new avenues for fundamental studies on Anderson localization in disordered plasmonic structures as well as its applications such as surface-enhanced Raman spectroscopy where localization behavior must be tuned to specific wave lengths.
T2 - 17th European Microscopy Congress (EMC 2024)
CY - Copenhagen, Denmark
DA - 26.08.2024
KW - Scanning electron microscopy
KW - Gold nanoparticle synthesis
KW - Disordered assemblies
KW - Localized surface plasmon resonances
KW - Transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618330
DO - https://doi.org/10.1051/bioconf/202412932007
VL - 129
SP - 1
EP - 2
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-61833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocaño, Patricia
A1 - Agudo Jácome, Leonardo
T1 - Creep degradation of the high entropy superalloy AlMo0.5NbTa0.5TiZr
N2 - The refractory high entropy superalloy (RSA) AlMo0.5NbTa0.5TiZr was the first of a class, with a dual-phase microstructure that resembles that of γ/γ’ in Ni-base superalloys), and the open question whether it performs better as structural alloy under high temperature (HT) applications. Here, we address the HT creep behavior and its associated microstructural degradation of this RSA.
The material was produced by arc-melting, heat treatment in argon (24 h @ 1400 °C + 4 h hot isostatic pressure @ 1370 °C & 170 MPa). Interrupted vacuum creep tests were performed at 900-1100 °C and 30-120 MPa. Scanning (S) and transmission (T) electron microscopy (EM) were used to reveal degradation mechanisms.
At 1100 °C (Fig.1, middle), the dual A2/B2 microstructure coarsens and partially transforms into a Zr-Al-rich phase (red arrow). An additional external load pronounces directional coarsening. Results are further discussed on the base dislocation and additional damage mechanisms.
T2 - International Conferende on Strength of Materials (ICSMA) 2022
CY - Metz, France
DA - 26.06.2022
KW - High entropy superalloy
KW - Rrafting
KW - Dislocation creep
KW - Phase transformation
PY - 2022
AN - OPUS4-63856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paulisch-Rinke, M. C.
A1 - Manzoni, Anna Maria
A1 - Agudo Jácome, Leonardo
A1 - Vogel, F.
A1 - Reimers, W.
T1 - Influence of chemical composition on microstructure and mechanical properties in the extruded aluminum alloys 7021B and 7175
N2 - The aim of this study is to improve the mechanical properties of Al 7xxx series alloys by achieving the strengthening benefits typically provided by Cu while avoiding the formation of low-melting eutectic phases associated with excessive Cu content. This is accomplished through a tailored combination of alloying elements and optimized thermomechanical treatments.
Alloys 7021B (high Zn content) and 7175 (high Cu and Mg content) are analyzed and optimized threefold in this study: the heat treatment, the microstructural evolution and the mechanical properties are investigated by several methods and compared with the aim of improving the process parameters for subsequent application.
The peak-aging process is optimized via compression tests to overcome the strength-ductility trade-off. Microstructure and phase chemistry analyses by transmission electron microscopy and atom probe tomography enable a better understanding of the underlying morphological features such as the spatial distribution, and the chemical composition of the hardening phases. The mechanical properties of the peak-aged alloys are determined by compression and tensile tests. Both alloys exhibit very high strength – even by 7xxx series standards. It can be traced back to the dislocation movement: it is impeded both by homogeneously distributed cuttable Guinier–Preston zones in both alloys and by non-cuttable η’ precipitates.
As a result, we demonstrate that alloy 7021B offers novel possibilities for processing and industrial application: high strength, typically associated with Cu containing alloys, can also be obtained in Cu free alloys, if the Zn content is sufficiently high. We can thus suggest new opportunities for processing and industrial applications by reducing the risk of forming low-melting eutectic phases.
KW - Aluminium alloys
KW - Transmission electron microscopy
KW - Atom probe tomography
KW - Extrusion
KW - Mechanical properties
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640338
DO - https://doi.org/10.1016/j.matdes.2025.114649
SN - 0264-1275
VL - 258
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-64033
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller-Elmau, Johanna
A1 - Göbel, Artur
A1 - Junge, Paul
A1 - Müller, Julian
A1 - Rousseau, Tom
A1 - Görke, Oliver
A1 - Nikasch, Christian
A1 - Kiliani, Stefan
T1 - Thermal cycling of YAG infiltration and plasma sprayed coatings as environmental barrier coating on ceramic heat shields for use in hydrogen operating gas turbines
N2 - Environmental barrier coatings (EBC) are intended to protect alumina ceramic tiles in hot water vapor conditions, enabling gas turbines to operate with higher hydrogen content or even pure hydrogen. For these operating conditions, yttrium aluminum garnet (YAG) promises the highest protection against hydrolysis, which can be applied via atmospheric plasmaspraying (APS). To enhance the protection efficiency, the coating is combined with a prior infiltration of the base material. The obtained design acts as in-depth protection even if the coating exhibits cracks.
KW - Thermal shock
KW - Thermal cycles
KW - Environmental barrier coating (EBC)
KW - Water vapor corrosion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639829
DO - https://doi.org/10.1016/j.oceram.2025.100837
VL - 23
SP - 1
EP - 7
PB - Elsevier Ltd.
AN - OPUS4-63982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Agudo Jácome, Leonardo
T1 - In situ electron-beam 'melting' (sublimation) of gold microparticles in the SEM
N2 - Gold micro particles have been modified in the past using the high power density of a localized electron beam of acceleration voltages above 100 kV as an energy source to transform matter at the sub-micron scale in a transmission electron microscope uses. Here, the e-beam-induced transformation of precursor microparticles employing a low-energy e-beam with an acceleration voltage of 30 kV in a scanning electron microscope is implemented. Under these conditions, the technique can be classified between e-beam lithography, where the e-beam is used to mill holes in or grow some different material onto a substrate, and e-beam welding, where matter can be welded together when overcoming the melting phase. Modifying gold microparticles on an amorphous SiOx substrate reveals the dominant role of inelastic electron-matter interaction and subsequent localized heating for the observed melting and vaporization of the precursor microparticles under the electron beam. Monte-Carlo scattering simulations and thermodynamic modeling further support the findings.
T2 - IKZ International Fellowship Award & Summer School 2025 from May 5 to 7, 2025
CY - Berlin, Germany
DA - 05.05.2025
KW - Gold Nanoparticle
KW - Scanning Electron Microscopy
KW - In situ irradiation
KW - Thermodynamic modelling
KW - Heat Transfer
PY - 2025
AN - OPUS4-63256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - van de Kreeke, Johannes
T1 - QI-Digital-Werkzeuge: DRMD
N2 - Im Rahmen der Initiative QI-Digital wird ein digitales Referenzmaterial-Zertifikat (DRMD) entwickelt. Es basiert auf dem digitalen Kalibrierzertifikat (DCC) und ist ebenso wie dieses ein Element des Quality-X-Ökosystems. Die Entwicklung fokussiert zunächst auf zwei Produkte: das DRMD-XML-Schema einerseits und einen DRMD-Generator andererseits, mit dem händisch und/oder mittels KI DRMD-Dateien generiert werden können. Als Repositorium - und vor allem auch als PR-Maßnahme - könnte die COMAR-Datenbank dienen.
T2 - Forum QI-Digital 2024
CY - Berlin, Germany
DA - 09.10.2024
KW - Digitalisierung
KW - Qualitätsinfrastruktur
PY - 2024
AN - OPUS4-61886
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gawlitza, Kornelia
T1 - Fluorescent molecularly imprinted polymer particles for direct detection of glyphosate in organic solvents and water
N2 - Glyphosate (GPS) is the most widely used pesticide in the world whose use increased dramatically after the introduction of genetically modified crops engineered to resist its herbicidal action during application. In recent years, there have been growing concerns over its toxicity following its classification by the International Agency for Research on Cancer (IARC) as a probable carcinogen as well as reports of its ecotoxicological effects. This resulted in increased efforts to develop quick and sensitive detection methods.
In this work, molecular imprinting was combined with direct fluorescence detection of GPS by improving its solubility in organic solvents using tetrabutylammonium (TBA+) and tetrahexylammonium (THA+) as counterions. To achieve fluorescence detection, a fluorescent crosslinker containing urea binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation. The GPS/fluorescent dye complexes were imprinted into 2–3 nm molecularly imprinted polymer (MIP) shells on the surface of sub-micron silica particles. Thus, the MIP binding behavior could be easily evaluated by fluorescence titrations in suspension to monitor the spectral changes upon addition of the GPS analytes. While MIPs prepared with GPS-TBA and GPS-THA both displayed satisfactory imprinting following titration with the corresponding analytes in chloroform, GPS-THA MIPs displayed better selectivity against competing molecules. Moreover, the THA+ counterion was found to be a more powerful phase transfer agent than TBA+, enabling the direct fluorescence detection and quantification of GPS in water in a biphasic assay. A limit of detection of 1.45 µM and a linear range of 5–55 µM, which matches well with WHO guidelines for the acceptable daily intake of GPS in water (5.32 µM), have been obtained. The assay can be further optimized to allow miniaturization into microfluidic devices and shows potential for on-field applications by untrained personnel.
T2 - 36th European Colloid & Interface Society Conference
CY - Chania, Greece
DA - 04.09.2022
KW - Glyphosate
KW - Molecular Imprinting
KW - Core-Shell Particles
KW - Fluorescent Urea Receptors
PY - 2022
AN - OPUS4-56311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Haas, S.
A1 - Kropf, H.
A1 - Duarte, J.
A1 - Cakir, Cafer Tufan
A1 - Dubois, F.
A1 - Többens, D.
A1 - Glatzel, U.
T1 - Temperature evolution of lattice misfit in Hf and Mo variations of the Al 10 Co 25 Cr 8 Fe 15 Ni 36 Ti 6 compositionally complex alloy
N2 - Misfits of γ- γ’ based Al10Co25Cr8Fe15Ni36Ti6 and its Mo- and Hf-variations are studied up to a temperature of 980 °C and compared with Ni- and Co-based superalloys. The trace elements decrease (Hf) or increase (Mo) the edge radii of the γ’ cuboids without changing their sizes. Atom probe measurements revealed that the Hf alloy prefers the γ’ phase while Mo prefers the γ matrix, leading to a lattice parameters enhancement of both phases, as could be revealed by synchrotron X-ray diffraction. The misfit is influenced in opposite ways: Hf increases the positive misfit, while Mo reduces it at all investigated temperatures.
KW - Metal and alloys
KW - Transmission electron microscopy
KW - X-ray diffraction
KW - Atom probe tomography
KW - High entropy alloy
PY - 2020
DO - https://doi.org/10.1016/j.scriptamat.2020.07.013
VL - 188
SP - 74
EP - 79
PB - Elsevier Ltd.
AN - OPUS4-51025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strommer, Bettina
A1 - Battig, Alexander
A1 - Schulze, Dietmar
A1 - Agudo Jácome, Leonardo
A1 - Schartel, Bernhard
A1 - Böhning, Martin
T1 - Shape, orientation, interaction, or dispersion: valorization of the influence factors in natural rubber nanocomposites
N2 - The addition of nanoparticles as reinforcing fillers in elastomers yields nanocomposites with unique property profiles, which opens the door for various new application fields. Major factors influencing the performance of nanocomposites are studied by varying the type and shape of nanoparticles and their dispersion in the natural rubber matrix. The industrial applicability of these nanocomposites is put into focus using two types of graphene and a nanoscale carbon black, all commercially available, and scalable processing techniques in the form of a highly filled masterbatch production via latex premixing by simple stirring or ultrasonically assisted dispersing with surfactant followed by conventional two-roll milling and hot pressing. Different processing and measurement methods reveal the potential for possible improvements: rheology, curing behavior, static and dynamic mechanical properties, swelling, and fire behavior. The aspect ratio of the nanoparticles and their interaction with the surrounding matrix prove to be crucial for the development of superior nanocomposites. An enhanced dispersing method enables the utilization of the improvement potential at low filler loadings (3 parts per hundred of rubber [phr]) and yields multifunctional rubber nanocomposites: two-dimensional layered particles (graphene) result in anisotropic material behavior with strong reinforcement in the in-plane direction (157% increase in the Young's modulus). The peak heat release rate in the cone calorimeter is reduced by 55% by incorporating 3 phr of few-layer graphene via an optimized dispersing process.
KW - Graphene
KW - Natural rubber
KW - Nanocomposites
KW - Anisotropy
KW - Fire behavior
PY - 2023
DO - https://doi.org/10.5254/rct.23.77961
SN - 0035-9475
SN - 1943-4804
VL - 96
IS - 1
SP - 40
EP - 58
PB - Allen Press
CY - Lawrence (KA), USA
AN - OPUS4-57568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andresen, Elina
T1 - Towards Development of Reference Test Materials for Metrology in Nanomedicine
N2 - The EPM-project “MetrINo” responds to the immediate metrological needs expressed by industry, regulators and policy makers for the development and validation of traceable measurement methods and reference materials (RMs) candidates for the assessment of CQAs of nanotherapeutics. The conference talk focuses on the preparation, homogeneity and stability studies of iron oxide and multi-element nanoparticles as candidate reference materials for size measurements. The developed materials aim to support the development and harmonization of traceable methodologies for nanoparticle characterization.
T2 - NME 2025
CY - Barcelona, Spain
DA - 27.05.2025
KW - IONPs
KW - Reference materials
KW - Lanthanide-based upconverting nanoparticles
PY - 2025
AN - OPUS4-63905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Johnston, L. J.
A1 - Zou, S.
T1 - Nanoscale reference and test materials for the validation of characterization methods for engineered nanomaterials — current state, limitations, and needs
N2 - The rational design of engineered nanomaterials (NMs) with improved functionality and their increasing industrial application requires reliable, validated, and ultimately standardized characterization methods for their application-relevant, physicochemical key properties such as size, size distribution, shape, or surface chemistry. This calls for nanoscale (certified)
reference materials (CRMs; RMs) and well-characterized reference test materials (RTMs) termed also quality control (QC) samples, assessed, e.g., in interlaboratory comparisons, for the validation and standardization of commonly used characterization methods. Thereby, increasing concerns regarding potential risks of NMs are also addressed and the road for safe and
sustainable-by-design concepts for the development of new functional NMs and their use as nanomedicines is paved. With this respect, we will provide an overview of relevant international standardization and regulatory activities, definitions, and recommendations on characterization methods and review currently available organic or inorganic nanoscale CRMs, RMs, and RTMs, including their characterization or certification. In addition, we will highlight typical applications to streamline the regulatory approval process and improve manufacturability including the special challenges imposed by the colloidal nature and sometimes limited stability of NMs. Subsequently, we will critically assess the limitations of currently available nanoscale RMs and RTMs and address the gaps to be filled in the future such as the availability of NMs that come with reference data on properties other than commonly addressed particle size, such as surface chemistry or particle number concentration, or
more closely resemble commercially available formulations or address application-relevant matrices.
KW - Nano
KW - Particle
KW - Silica
KW - Quality assurance
KW - Reference material
KW - Review
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Lipid nanoparticles
KW - Metal nanoparticles
KW - Liposomes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625746
DO - https://doi.org/10.1007/s00216-024-05719-6
SN - 1618-2650
SP - 1
EP - 21
PB - Springer
AN - OPUS4-62574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Labrador-Paez, Lucia, L.
A1 - Kankare, J.
A1 - Hyppanen, I.
A1 - Soukka, T.
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Widengren, J
A1 - Liu, H.
T1 - Frequency-Domain Method for Characterization of Upconversion Luminescence Kinetics
N2 - The frequency-domain (FD) method provides an alternative to the commonly used time-domain (TD) approach in characterizing the luminescence kinetics of luminophores, with its own strengths, e.g., the capability to decouple multiple lifetime components with higher reliability and accuracy. While extensively explored for characterizing luminophores with down-shifted emission, this method has not been investigated for studying nonlinear luminescent materials such as lanthanide-doped upconversion nanoparticles (UCNPs), featuring more complicated kinetics. In this work, employing a simplified rate-equation model representing a standard two-photon energy-transfer upconversion process, we thoroughly analyzed the response of the luminescence of UCNPs in the FD method. We found that the FD method can potentially obtain from a single experiment the effective decay rates of three critical energy states of the sensitizer/activator ions involved in the upconversion process. The validity of the FD method is demonstrated by experimental data, agreeing reasonably well with the results obtained by TD methods.
KW - Quality assurance
KW - Luminescence
KW - Method
KW - Quantitative spectroscopy
KW - Nano
KW - Particle
KW - Lifetime
KW - Method development
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597435
DO - https://doi.org/10.1021/acs.jpclett.3c00269
SP - 3436
EP - 3444
AN - OPUS4-59743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Introduction to Fluorescence Spectroscopy
N2 - A brief introduction to fluorescence spectroscopy will be provided, ranging from typically measured fluorescence quantities over instrument-specific contributions to measured fluorescence signals to selected applications. In this context, an overview of the photoluminescence properties of molecular and nanoscale luminescence reporters will be given including a brief insight into their photophysics and fluorescence standards designed by division Biophotonics for the calibration and instrument performance validation of fluorescence measuring devices will be presented.
T2 - Analytical Academy
CY - Berlin, Germany
DA - 13.01.2020
KW - Linearity
KW - Fluorescence
KW - Dye
KW - Quality assurance
KW - Nnano particle
KW - Method
KW - Measurement uncertainty
KW - Quantification
PY - 2020
AN - OPUS4-51618
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Career Options in Public Service
N2 - In the following, an overview of possible career options for chemists is presented covering metrology institutes, departmental research institutes of ministries, Federal and state research institutes and options in areas such as Federal or state institutions in charge of occupational safety, the German armed forces, wastewater treatment plants and labs/institutes controlling water quality, and museums. Thereby also examples and personal insights of the daily work routine are provided for some employers.
T2 - Career-Workshop ChiÖD
CY - Karlsruhe, Germany
DA - 02.04.2025
KW - Quality assurance
KW - Reference analysis
KW - Standardization
KW - Metrology
KW - Reference products
KW - Reference materials
KW - Mission
PY - 2025
AN - OPUS4-62867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - From molecular and nanoscale chromophores with UV/VIS/NIR/SWIR luminescence to multi method characterization of surface coatings
N2 - An overview of the research activities of division Biophotonics is presented covering examples for photophysical studies of different types of molecular and nanocrystalline luminophores, luminescent particles, and sensor systems in solution, in dispersion, and in the solid state and multi-method charactreization workflow for the characterization of surface-functionalized engineered nanomaterials. In addition, the importance of reliable optical measurements, particularly standardized workflows for the determination of the key performance parameter luminescence quantum yield of transparent and scattering luminescent samples with fluorescence and integrating sphere spectroscopy, and validated methods for quantifying surface functional groups and ligands on nanomaterials is highlighted. Thereby, also ongoing standardization activities are presented as well as certified reference materials and reference materials from division Biophotonics.
T2 - Chinese-German Chemical Association - Annual Meeting
CY - Berlin, Germany
DA - 22.08.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - Characterization
KW - Advanced material
KW - Surface
KW - Lifetime
KW - Sensor
KW - Oxygen
KW - Ph
KW - Standardization
KW - Fluorescent probe
KW - Reference material
PY - 2025
AN - OPUS4-64181
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Clark, P.C.J
A1 - Andresen, Elina
A1 - Sear, M. J.
A1 - Favaro, M.
A1 - Girardi, L.
A1 - van de Krol, R.
A1 - Resch-Genger, Ute
A1 - Starr, D.E.
T1 - Quantification of the Activator and Sensitizer Ion Distributions in NaYF4:Yb3+, Er3+ Upconverting Nanoparticles Via Depth-Profiling with Tender X-Ray Photoemission
N2 - The spatial distribution and concentration of lanthanide activator and sensitizer dopant ions are of key importance for the luminescence color and efficiency of upconverting nanoparticles (UCNPs). Quantifying dopant ion distributions and intermixing, and correlating them with synthesis methods require suitable analytical techniques. Here, X-ray photoelectron spectroscopy depth-profiling with tender X-rays (2000–6000 eV), providing probe depths ideally matched to UCNP sizes, is used to measure the depth-dependent concentration ratios of Er3+ to Yb3+, [Er3+]/[Yb3+], in three types of UCNPs prepared using different reagents and synthesis methods. This is combined with data simulations and inductively coupled plasma-optical emission spectroscopy (ICP-OES) measurements of the lanthanide ion concentrations to construct models of the UCNPs’ dopant ion distributions. The UCNP sizes and architectures are chosen to demonstrate the potential of this approach. Core-only UCNPs synthesized with XCl3·6H2O precursors (β-phase) exhibit a homogeneous distribution of lanthanide ions, but a slightly surface-enhanced [Er3+]/[Yb3+] is observed for UCNPs prepared with trifluroacetate precursors (α-phase). Examination of Yb-core@Er-shell UCNPs reveals a co-doped, intermixed region between the single-doped core and shell. The impact of these different dopant ion distributions on the UCNP's optical properties is discussed to highlight their importance for UCNP functionality and the design of efficient UCNPs.
KW - Shell
KW - Nanomaterial
KW - Nano
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Excitation power density
KW - Surface
KW - Coating
KW - Core-shell
KW - XPS
KW - Intermixing
KW - HAXPES
KW - Method
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552075
DO - https://doi.org/10.1002/smll.202107976
SN - 1613-6813
SP - 1
EP - 13
PB - Wiley-VCH-Verlag
CY - Weinheim, Germany
AN - OPUS4-55207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, C.
A1 - Schwibbert, Karin
A1 - Gadicherla, A. K.
A1 - Thiele, Dorothea
A1 - Nirmalananthan-Budau, Nithiya
A1 - Laux, P.
A1 - Resch-Genger, Ute
A1 - Luch, A.
A1 - Tschiche, H. R.
T1 - Monitoring and imaging pH in biofilms utilizing a fluorescent polymeric nanosensor
N2 - Biofilms are ubiquitous in nature and in the man-made environment. Given their harmful effects on human health, an in-depth understanding of biofilms and the monitoring of their formation and growth are important. Particularly relevant for many metabolic processes and survival strategies of biofilms is their extracellular pH. However, most conventional techniques are not suited for minimally invasive pH measurements of living biofilms. Here, a fluorescent nanosensor is presented for ratiometric measurements of pH in biofilms in the range of pH 4.5–9.5 using confocal laser scanning microscopy. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with pH-inert dye Nile Red and is surface functionalized with a pH-responsive fluorescein dye. Its performance was validated by fluorometrically monitoring the time-dependent changes in pH in E. coli biofilms after glucose inoculation at 37 °C and 4 °C. This revealed a temperature-dependent decrease in pH over a 4-h period caused by the acidifying glucose metabolism of E. coli. These studies demonstrate the applicability of this nanosensor to characterize the chemical microenvironment in biofilms with fluorescence methods.
KW - Dye
KW - Fluorescence
KW - Signal enhancement
KW - Sensor
KW - Quantum yield
KW - Synthesis
KW - Nanoparticle
KW - Nano
KW - Polymer
KW - Ph
KW - Biofilm
KW - MIC
KW - Corrosion
KW - Microorganism
KW - Bacteria
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550751
DO - https://doi.org/10.1038/s41598-022-13518-1
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 10
PB - Nature Publishing Group
CY - London
AN - OPUS4-55075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Eckert, J. G.
A1 - Lutowski, Marc
A1 - Geißler, Daniel
A1 - Hertwig, Andreas
A1 - Hidde, Gundula
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Influence of nanoparticle encapsulation and encoding on the surface chemistry of polymer carrier beads
N2 - Surface-functionalized polymer beads encoded with molecular luminophores and nanocrystalline emitters such as semiconductor nanocrystals, often referred to as quantum dots (QDs), or magnetic nanoparticles are broadly used in the life sciences as reporters and carrier beads. Many of these applications require a profound knowledge of the chemical nature and total number of their surface functional groups (FGs), that control bead charge, colloidal stability, hydrophobicity, and the interaction with the environment and biological systems. For bioanalytical applications, also the number of groups accessible for the subsequent functionalization with, e.g., biomolecules or targeting ligands is relevant. In this study, we explore the influence of QD encoding on the amount of carboxylic acid (COOH) surface FGs of 2 μm polystyrene microparticles (PSMPs). This is done for frequently employed oleic acid and oleylamine stabilized, luminescent core/shell CdSe QDs and two commonly used encoding procedures. This included QD addition during bead formation by a thermally induced polymerization reaction and a post synthetic swelling procedure. The accessible number of COOH groups on the surface of QD-encoded and pristine beads was quantified by two colorimetric assays, utilizing differently sized reporters and electrostatic and covalent interactions. The results were compared to the total number of FGs obtained by a conductometric titration and Fourier transform infrared spectroscopy (FTIR). In addition, a comparison of the impact of QD and dye encoding on the bead surface chemistry was performed. Our results demonstrate the influence of QD encoding and the QD-encoding strategy on the number of surface FG that is ascribed to an interaction of the QDs with the carboxylic acid groups on the bead surface. These findings are of considerable relevance for applications of nanoparticle-encoded beads and safe-by-design concepts for nanomaterials.
KW - Optical spectroscopy
KW - Particle
KW - Optical assay
KW - IR spectroscopy
KW - Fluorescence
KW - Quantum yield
KW - Quality assurance
KW - Nano
KW - Synthesis
KW - Surface chemistry
KW - Quantification
KW - Method
KW - Conductometry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581502
DO - https://doi.org/10.1038/s41598-023-38518-7
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 15
PB - Springer Nature
CY - London
AN - OPUS4-58150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reiber, T.
A1 - Hübner, Oskar
A1 - Dose, C.
A1 - Yushchenko, D. A.
A1 - Resch-Genger, Ute
T1 - Fluorophore multimerization on a PEG backbone as a concept for signal amplification and lifetime modulation
N2 - Fluorescent labels have strongly contributed to many advancements in bioanalysis, molecular biology, molecular imaging, and medical diagnostics. Despite a large toolbox of molecular and nanoscale fluorophores to choose from, there is still a need for brighter labels, e.g., for flow cytometry and fluorescence microscopy, that are preferably of molecular nature. This requires versatile concepts for fluorophore multimerization, which involves the shielding of dyes from other chromophores and possible quenchers in their neighborhood. In addition, to increase the number of readout parameters for fluorescence microscopy and eventually also flow cytometry, control and tuning of the labels’ fluorescence lifetimes is desired. Searching for bright multi-chromophoric or multimeric labels, we developed PEGylated dyes bearing functional groups for their bioconjugation and explored their spectroscopic properties and photostability in comparison to those of the respective monomeric dyes for two exemplarily chosen fluorophores excitable at 488 nm. Subsequently, these dyes were conjugated with anti-CD4 and anti-CD8 immunoglobulins to obtain fluorescent conjugates suitable for the labeling of cells and beads. Finally, the suitability of these novel labels for fluorescence lifetime imaging and target discrimination based upon lifetime measurements was assessed. Based upon the results of our spectroscopic studies including measurements of fluorescence quantum yields (QY) and fluorescence decay kinetics we could demonstrate the absence of significant dye-dye interactions and self-quenching in these multimeric labels. Moreover, in a first fluorescence lifetime imaging (FLIM) study, we could show the future potential of this multimerization concept for lifetime discrimination and multiplexing.
KW - Imaging
KW - Quantum yield
KW - Quality assurance
KW - Antibody
KW - Conjugate
KW - Cell
KW - FLIM
KW - PEG
KW - Flow cytometry
KW - Lifetime
KW - Energy transfer
KW - Quantitative spectroscopy
KW - Nano
KW - Particle
KW - Fluorescence
KW - Dye
KW - Amplification
KW - Microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602197
DO - https://doi.org/10.1038/s41598-024-62548-4
SN - 2045-2322
VL - 14
IS - 1
SP - 1
EP - 11
AN - OPUS4-60219
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Resch-Genger, Ute
T1 - The 2023 Nobel Prize in Chemistry: Quantum dots
N2 - The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery.
KW - Quantum dots
KW - Semiconductor nanocrystals
KW - Luminescence
KW - Quantitative spectroscopy
KW - Quantum yield
KW - Advanced nanomaterials
KW - Quality assurance
KW - Energy transfer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597843
DO - https://doi.org/10.1007/s00216-024-05225-9
VL - 2024
SP - 1
EP - 11
PB - Springer
CY - Cham
AN - OPUS4-59784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohammad, W.
A1 - Wegner, Karl David
A1 - Comby-Zerbino, C.
A1 - Trouillet, V.
A1 - Ogayer, M. P.
A1 - Coll, J.-L.
A1 - Marin, R.
A1 - Jaque Garcia, D.
A1 - Resch-Genger, Ute
A1 - Antoine, R.
A1 - Le Guevel, X.
T1 - Enhanced brightness of ultra-small gold nanoparticles in the second biological window through thiol ligand shell control
N2 - Gold-based nanoparticles below 2 nm in size are promising as luminescent probes for in vivo bioimaging, owing to their brightness and rapid renal clearance. However, their use as contrast agents in the near-infrared II (NIR-II, 1000–1700 nm) range remains challenging due to their low photoluminescence (PL) quantum yield. To address this, PL enhancement can be achieved by either rigidifying the ligand-shell structure or increasing the size of the ligand shell. In this study, we synthesized ultra-small gold nanoparticles stabilized by co-ligands, namely monothiol and short dithiol molecules. By precisely controlling the amount of reducing agent used during particle preparation, we successfully modulated the physicochemical properties of the co-ligand shell, including its size, composition, and structure. Consequently, we achieved a remarkable 60-fold increase in the absorption cross-section at 990 nm while maintaining the small size of the 1.5-nm metal core. The analytical and optical characterization of our thiol-capped gold nanoparticles indicates that the ligand shell size is governed by the quantity of the reducing agent, which, in turn, impacts the balance between radiative and non-radiative processes, thereby influencing the PL quantum yield.
KW - Gold nanocluster
KW - NIR-II fluorescence
KW - SWIR
KW - Nanomaterial design
KW - Calibrated fluorescence measurements
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588117
DO - https://doi.org/10.1039/D3TC03021K
SN - 2050-7526
VL - 11
IS - 42
SP - 14714
EP - 14724
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fiedler, Saskia
A1 - Frenzel, Florian
A1 - Würth, Christian
A1 - Tavernaro, Isabella
A1 - Grüne, M.
A1 - Schweizer, S.
A1 - Engel, A.
A1 - Resch-Genger, Ute
T1 - Interlaboratory Comparison on Absolute Photoluminescence Quantum Yield Measurements of Solid Light Converting Phosphors with Three Commercial Integrating Sphere Setups
N2 - Scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders are increasingly relevant for fundamental research and industry. Examples are luminescent nano- and microparticles and phosphors of different compositions in various matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter to characterize the performance of these materials is the photoluminescence/fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. To identify and quantify the sources of uncertainty of absolute measurements of Φf of scattering samples, the first interlaboratory comparison (ILC) of three laboratories from academia and industry was performed by following identical measurement protocols. Thereby, two types ofcommercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring the Φf of transparent and scattering dye solutions and solid phosphors, namely, YAG:Ce optoceramics of varying surface roughness, used as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While the Φf values of the liquid samples matched between instruments, Φf measurements of the optoceramics with different blanks revealed substantial differences. The ILC results underline the importance of the measurement geometry, sample position, and blank for reliable Φf data of scattering the YAG:Ce optoceramics, with the blank’s optical properties accounting for uncertainties exceeding 20%.
KW - Nano
KW - Fluorescence
KW - Reference material
KW - Luminescence
KW - Quantitative spectroscopy
KW - Particle
KW - Quantum yield
KW - Quality assurance
KW - Phosphor
KW - Converter material
KW - Lifetime
KW - Interlaboratory comparison
KW - Method
KW - Uncertainty
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600945
DO - https://doi.org/10.1021/acs.analchem.4c00372
SN - 0003-2700
SP - 6730
EP - 6737
PB - ACS Publications
AN - OPUS4-60094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Cui
A1 - Ebel, Kenny
A1 - Heinze, Katja
A1 - Resch-Genger, Ute
A1 - Bald, Ilko
T1 - Quantum Yield of DNA Strand Breaks under Photoexcitation of a Molecular Ruby
N2 - Photodynamic therapy (PDT) used for treating cancer relies on the generation of highly reactive oxygen species, for example, singlet oxygen 1O2, by light-induced excitation of a photosensitizer (PS) in the presence of molecular oxygen, inducing DNA damage in close proximity of the PS. Although many precious metal complexes have been explored as PS for PDT and received clinical approval, only recently, the potential of photoactive complexes of nonnoble metals as PS has been discovered. Using the DNA origami technology that can absolutely quantify DNA strand break cross sections, we assessed the potential of the luminescent transition metal complex [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) to damage DNA in an air-saturated aqueous environment upon UV/Vis illumination. The quantum yield for strand breakage, that is, the ratio of DNA strand breaks to the number of absorbed photons, was determined to 1–4%, indicating efficient transformation of photons into DNA strand breaks by [Cr(ddpd)2]3+.
KW - Fluorescence
KW - Synthesis
KW - Production
KW - Optical spectroscopy
KW - Ligand
KW - Photophysics
KW - Cr(III)
KW - Mechanism
KW - NIR
KW - PDT
KW - Singlet oxygen
KW - DNA
KW - Origami
KW - Quantum yield
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573631
DO - https://doi.org/10.1002/chem.202203719
SP - 1
EP - 7
AN - OPUS4-57363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Iglesias, C.
A1 - Markovina, A.
A1 - Nirmalananthan-Budau, N.
A1 - Resch-Genger, Ute
A1 - Klinger, D.
T1 - Optically monitoring the microenvironment of a hydrophobic cargo in amphiphilic nanogels: influence of network composition on loading and release
N2 - Amphiphilic nanogels (ANGs) are promising carriers for hydrophobic cargos such as drugs, dyes, and catalysts.
Loading content and release kinetics of these compounds are controlled by type and number of hydrophobic groups in the amphiphilic copolymer network. Thus, understanding the interactions between cargo and colloidal carrier is mandatory for a tailor-made and cargo-specific ANG design. To systematically explore the influence of the network composition on these interactions, we prepared a set of ANGs of different amphiphilicity and loaded these ANGs with varying concentrations of the solvatochromic dye Nile Red (NR). Here, NR acts as a hydrophobic model cargo to optically probe the polarity of its microenvironment. Analysis of the NR emission spectra as well as measurements of the fluorescence quantum yields and decay kinetics revealed a decrease in the polarity of the NR microenvironment with increasing hydrophobicity of the hydrophobic groups in the ANG network and dye–dye interactions at higher loading concentrations. At low NR concentrations, the hydrophobic cargo NR is encapsulated in the hydrophobic domains. Increasing NR concentrations resulted in probe molecules located in a more hydrophilic environment, i.e., at the nanodomain border, and favored dye–dye interactions and NR aggregation.
These results correlate well with release experiments, indicating first NR release from more hydrophilic network locations. Overall, our findings demonstrate the importance to understand carrier–drug interactions for efficient loading and controlled release profiles in amphiphilic nanogels.
KW - Particle
KW - Energy transfer
KW - Limit of detection
KW - Polymer
KW - Luminescence
KW - Quantitative spectroscopy
KW - Nano
KW - Quantum yield
KW - Lifetime
KW - Quality assurance
KW - Dye
KW - Probe
KW - Sensor
KW - Nile Red
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601603
DO - https://doi.org/10.1039/d4nr00051j
SN - 2040-3364
IS - 16
SP - 9525
EP - 9535
PB - The Royal Society of Chemistry
AN - OPUS4-60160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Matiushkina, Anna
A1 - Rother, Kai Simon
A1 - Mating, Celina
A1 - Resch-Genger, Ute
T1 - Exploring the potential of simple automation concepts for quantifying functional groups on nanomaterials with optical assays
N2 - Until now, automation in nanomaterial research has been largely focused on the automated synthesis of engineered nanoparticles (NPs) including the screening of synthesis parameters and the automation of characterization methods such as electron microscopy. Despite the rapidly increasing number of NP samples analyzed due to increasing requirements on NP quality control, increasing safety concerns, and regulatory requirements, automation has not yet been introduced into workflows of analytical methods utilized for screening, monitoring, and quantifying functional groups (FGs) on NPs. To address this gap, we studied the potential of simple automation tools for the quantification of amino surface groups on different types of aminated NPs, varying in size, chemical composition, and optical properties, with the exemplarily chosen sensitive optical fluorescamine (Fluram) assay. This broadly applied, but reportedly error-prone assay, which utilizes a chromogenic reporter, involves multiple pipetting and dilution steps and photometric or fluorometric detection. In this study, we compared the influence of automated and manual pipetting on the results of this assay, which was automatically read out with a microplate reader. Special emphasis was dedicated to parameters like accuracy, consistency, achievable uncertainties, and speed of analysis and to possible interferences from the NPs. Our results highlight the advantages of automated surface FG quantification and the huge potential of automation for nanotechnology. In the future, this will facilitate process and quality control of NP fabrication, surface modification, and stability monitoring and help to produce large data sets for nanomaterial grouping approaches for sustainable and safe-by-design, performance, and risk assessment studies.
KW - Automation
KW - Quantification of amino groups
KW - Fluorescamine assay
KW - Amorphous silica nanoparticles
KW - Iron oxide nanoparticles
KW - Upconversion nanoparticles
PY - 2024
DO - https://doi.org/10.1007/s12274-024-6970-1
VL - 17
IS - 11
SP - 10119
EP - 10126
PB - Springer
AN - OPUS4-61459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Sander, P. C.
A1 - Andresen, Elina
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Expanding the Toolbox of Simple, Cost-Efficient, and Automatable Methods for Quantifying Surface Functional Groups on Nanoparticles� Potentiometric Titration
N2 - Measuring surface functional groups (FGs) on nanomaterials (NMs) is essential for designing dispersible and stable NMs with tailored and predictable functionality. FG screening and quantification also plays a critical role for subsequent processing steps, NM long-term stability, quality control of NM production, and risk assessment studies and enables the implementation of sustainable and safe(r)-by-design concepts. This calls for simple and cost-efficient methods for broadly utilized FGs that can be ideally automated to speed up FG screening, monitoring, and quantification. To expand our NM surface analysis toolbox, focusing on simple methods and broadly available, cost-efficient instrumentation, we explored a NM-adapted pH titration method with potentiometric and optical readout for measuring the total number of (de)protonable FGs on representatively chosen commercial and custom-made aminated silica nanoparticles (SiO2 NPs). The accuracy and robustness of our stepwise optimized workflows was assessed by several operators in two laboratories and method validation was done by cross-comparison with two analytical methods relying on different signal generation principles. This included traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA), providing the amounts of amino silanes released by particle dissolution and the total mass of the surface coatings. A comparison of the potentiometric titration results with the reporter-specific amounts of surface amino FGs determined with the previously automated fluorescamine (Fluram) assay highlights the importance of determining both quantities for surface-functionalized NMs. In the future, combined NM surface analysis with optical assays and pH titration will simplify quality control of NM production processes and stability studies and can yield large data sets for NM grouping that facilitates further developments in regulation and standardization.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - Fluorescamine
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642371
DO - https://doi.org/10.1021/acsmeasuresciau.5c00062
SN - 2694-250X
SP - 1
EP - 13
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-64237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stiegler, L. M. S.
A1 - Wegner, Karl David
A1 - Weigert, Florian
A1 - Peukert, W.
A1 - Resch-Genger, Ute
A1 - Walter, J.
T1 - Analysis of Giant-Shell CdSe/CdS Quantum Dots via Analytical Ultracentrifugation Combined with Spectrally Resolved Photoluminescence
N2 - Knowledge of the structure–property relationships of functional nanomaterials, including, for example, their size- and composition-dependent photoluminescence (PL) and particle-to-particle variations, is crucial for their design and reproducibility. Herein, the Angstrom-resolution capability of an analytical ultracentrifuge combined with an in-line multiwavelength emission detection system (MWE-AUC) for measuring the sedimentation coefficient-resolved spectrally corrected PL spectra of dispersed nanoparticles is demonstrated. The capabilities of this technique are shown for giant-shell CdSe/CdS quantum dots (g-QDs) with a PL quantum yield (PL QY) close to unity capped with oleic acid and oleylamine ligands. The MWE-AUC PL measurements are calibrated and validated with certified fluorescence standards. The spectrally corrected and size-dependent PL spectra of the g-QDs derived from a single MWE-AUC experiment are then analyzed and compared with the results of single-particle spectroscopic studies, yielding the PL spectra, decay kinetics, and blinking behavior of individual g-QDs. This study underlines the vast potential of MWE-AUC with in-line optical detection for the characterization of advanced nanomaterials with a complex structure.
KW - Quantum dots
KW - Analytical ultracentrifugation
KW - Photoluminescence
KW - Advanced nanomaterial characterization
KW - Calibrated fluorescence measurements
KW - Reference materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624357
DO - https://doi.org/10.1002/smtd.202401700
SN - 2366-9608
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-62435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Extending certified spectral fluorescence standards for the calibration and performance validation of fluorescence instruments to the NIR—closing the gap from 750 to 940 nm with two novel NIR dyes
N2 - Fluorescence techniques such as fluorescence spectroscopy, microfluorometry, and fluorescence microscopy, providing spectral, intensity, polarization, and lifetime information, are amongst the most broadly utilized analytical methods in the life and materials sciences. However, the measured fluorescence data contain sample- and instrument-specific contributions, which hamper their comparability across instruments and laboratories. Comparable, instrument-independent fluorescence data require the determination of the fluorescence instrument’s wavelength-dependent spectral responsivity, also termed emission correction curve, for the same instrument settings as those used for the fluorescence measurements as a prerequisite for the subsequent correction of the measured instrument-specific data. Such a spectral correction is essential for the performance comparison of different fluorescent labels and reporters, quantitative fluorescence measurements, the determination of the fluorescence quantum yield, and the spectroscopic measure for the fluorescence efficiency of a fluorophore. Simple-to-use tools for obtaining emission correction curves are chromophore-based reference materials (RMs), referred to as fluorescence standards, with precisely known, preferably certified instrument-independent fluorescence spectra. However, for the increasingly used near-infrared (NIR) wavelength region >700 nm, at present, no spectral fluorescence standards are available. To close this gap, we developed two novel spectral fluorescence standards, BAM F007 and BAM-F009, with broad emission bands from about 580 to 940 nm in ethanolic solution. These liquid fluorescence standards currently under certification, which will be released in 2025, will expand the wavelength range of the already available certified Calibration Kit BAM F001b-F005b from about 300–730 to 940 nm. In this research article, we will detail the criteria utilized for dye and matrix selection and the homogeneity and stability tests accompanying dye certification as well as the calculation of the wavelength-dependent uncertainty budgets of the emission spectra BAM F007 and BAM-F009, determined with the traceably calibrated BAM reference spectrofluorometer. These fluorescence standards can provide the basis for comparable fluorescence measurements in the ultraviolet, visible, and NIR for the fluorescence community.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626317
DO - https://doi.org/10.1007/s00216-024-05723-w
SN - 1618-2650
SP - 1
EP - 15
PB - Springer
AN - OPUS4-62631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deumer, J.
A1 - Andresen, Elina
A1 - Gollwitzer, C.
A1 - Schürmann, R.
A1 - Resch-Genger, Ute
T1 - Adding More Shape to Nanoscale Reference Materials-LiYF4:Yb,Tm Bipyramids as Standards for Sizing Methods and Particle Number Concentration
N2 - The increasing industrial use of nanomaterials calls for the reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry, and test and reference materials (RMs) with sizes and shapes, closely matching real-world nonspheric nano-objects. An efficient strategy to minimize efforts in producing nanoscale RMs (nanoRMs) for establishing, validating, and standardizing methods for characterizing nanomaterials are multimethod nanoRMs.
Ideal candidates are lanthanide-based, multicolor luminescent, and chemically inert nanoparticles (NPs) like upconversion nanoparticles (UCNPs), which can be prepared in different sizes, shapes, and chemical composition with various surface coatings. This makes UCNPs interesting candidates as standards not only for sizing methods, but also for element-analytical methods like laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), quantitative bioimaging methods like X-ray fluorescence computed tomography (XFCT), and luminescence methods and correlative measurements.
Here, we explore the potential of two monodisperse LiYF4:Yb,Tm bipyramids with peak-to-peak distances of (43 ± 2) nm and (29 ± 2) nm as size standards for small-angle X-ray scattering (SAXS) and tools for establishing and validating the sophisticated simulations required for the analysis of SAXS data derived from dispersions of nonspheric nano-objects. These SAXS studies are supplemented by two-dimensional (2D)-transmission electron microscopy measurements of the UCNP bipyramids. Additionally, the particle number concentration of cyclohexane dispersions of these UCNP bipyramids is determined by absolute SAXS measurements, complemented by gravimetry, thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectrometry (ICP-OES). This approach enables traceable particle number concentration measurements of ligand-capped nonspheric particles with unknown chemical composition.
KW - Fluorescence
KW - Upconversion nanoparticles
KW - SAXS
KW - Particle number concentration
KW - Reference material
KW - Traceability
KW - Quality assurance
KW - Quantum yield
KW - Spectroscopy
KW - Synthesis
KW - Quantification
KW - NanoRM
KW - Nano
KW - Particle
KW - Bipyramid
KW - Reference data
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617940
DO - https://doi.org/10.1021/acs.analchem.4c03641
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-61794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahiboz, D.
A1 - Andresen, Elina
A1 - Manley, P.
A1 - Resch-Genger, Ute
A1 - Würth, Christian
A1 - Becker, C.
T1 - Metasurface-Enhanced Photon Upconversion upon 1550 nm Excitation
N2 - Photon upconversion upon 1550 nm excitation is of high relevance for applications in the third biological excitation window, for photovoltaics beyond current limitations, and enables appealing options in the field of glass Fiber telecommunications. Trivalent doped erbium ions (Er3+) are the material of choice for 1550 nm excited upconversion, however, they suffer from a low absorption cross-section and a low brightness. Therefore, the ability of Silicon metasurfaces to provide greatly enhanced electrical near-fields is employed to enable efficient photon upconversion even at low external Illumination conditions. Hexagonally shaped β-NaYF4:Er3+ nanoparticles are placed on large-area silicon metasurfaces designed to convert near-infrared (1550 nm) to visible light. More than 2400-fold enhanced photon upconversion luminescence is achieved by using this metasurface instead of a planar substrate.
With the aid of optical simulations based on the finite-element method, this result is attributed to the coupling of the excitation source with metasurface resonances at appropriate incident angles. Analysis of the excitation power density dependence of upconversion luminescence and red-to-green-emission ratios enables the estimation of nanoscale near-field enhancement on the metasurface. The findings permit the significant reduction of required external excitation intensities for photon upconversion of 1550 nm light, opening perspectives in biophotonics, telecommunication, and photovoltaics.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Excitation power density
KW - Single particle
KW - Brightness
KW - NIR
KW - Mechanism
KW - Single enhancement
KW - SWIR
KW - Method
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537193
DO - https://doi.org/10.1002/adom.202101285.
SN - 2195-1071
VL - 9
IS - 24
SP - 2101285
PB - Wiley-VCH-GmbH
AN - OPUS4-53719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Carl, F.
A1 - Grauel, Bettina
A1 - Pons, Monica
A1 - Würth, Christian
A1 - Haase, M.
T1 - LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals
N2 - We developed a procedure to prepare luminescent LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with a size of approximately 40 nm revealing luminescence decay times of the dopant ions that approach those of high-quality laser crystals of LiYF4:Yb (Yb:YLF) and LiYF4:Yb,Er (Yb,Er:YLF) with identical doping concentrations. As the luminescence decay times of Yb3+ and Er3+ are known to be very sensitive to the presence of quenchers, the long decay times of the core/shell nanocrystals indicate a very low number of defects in the core particles and at the core/shell interfaces. This improvement in the performance was achieved by introducing two important modifications in the commonly used oleic acid based synthesis. First, the shell was prepared via anewly developed method characterized by a very low nucleation rate for particles of pure LiYF4 shell material. Second, anhydrous acetates were used as precursors and additional drying steps were applied to reduce the incorporation of OH− in the crystal lattice, known to quench the emission of Yb3+ ions. Excitation power density (P)-dependent absolute measurements of the upconversion luminescence quantum yield (Φ,UC) of LiYF4:Yb,Er/LiYF4 core/shell particles reveal a maximum value of 1.25% at P of 180 W·cm−2.
Although lower than the values reported for NaYF4:18%Yb,2%Er core/shell nanocrystals with comparable sizes, these Φ, UC values are the highest reported so far for LiYF4:18%Yb,2%Er/LiYF4 nanocrystals without additional dopants. Further improvements May nevertheless be possible by optimizing the dopant concentrations in the LiYF4 nanocrystals.
KW - Nano
KW - Crystal
KW - Quantum yield
KW - LiYF4
KW - Synthesis
KW - Lifetime
KW - Fluorescence
KW - NIR
KW - Photoluminescence
KW - Lanthanide
KW - Upconversion nanoparticle
KW - Nanomaterial
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515395
DO - https://doi.org/10.1007/s12274-020-3116-y
SN - 1998-0124
VL - 14
IS - 3
SP - 797
EP - 806
PB - Springer
AN - OPUS4-51539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Grauel, Bettina
A1 - Pons, Monika
A1 - Frenzel, Florian
A1 - Rissiek, P.
A1 - Rücker, Kerstin
A1 - Haase, Markus
A1 - Resch-Genger, Ute
T1 - Yb- and Er concentration dependence of the upconversion luminescence of highly doped NaYF4:Yb,Er/NaYF4:Lu core/shell nanocrystals prepared by a water-free synthesis
N2 - High sensitizer and activator concentrations have been increasingly examined to improve the performance of multi-color emissive upconversion (UC) nanocrystals (UCNC) like NaYF4:Yb,Er and first strategies were reported to reduce concentration quenching in highly doped UCNC. UC luminescence (UCL) is, however, controlled not only by dopant concentration, yet by an interplay of different parameters including size, crystal and shell quality, and excitation power density (P). Thus, identifying optimum dopant concentrations requires systematic studies of UCNC designed to minimize additional quenching pathways and quantitative spectroscopy. Here, we quantify the dopant concentration dependence of the UCL quantum yield (ΦUC) of solid
NaYF4:Yb,Er/NaYF4:Lu upconversion core/shell nanocrystals of varying Yb3+ and Er3+ concentrations (Yb3+ series: 20%‒98% Yb3+; 2% Er3+; Er3+ series: 60% Yb3+; 2%‒40% Er3+). To circumvent other luminescence quenching processes, an elaborate synthesis yielding OH-free UCNC with record ΦUC of ~9% and ~25 nm core particles with a thick surface shell were used. High Yb3+ concentrations barely reduce ΦUC from ~9% (20% Yb3+) to ~7% (98% Yb3+) for an Er3+ concentration of 2%, thereby allowing to strongly increase the particle absorption cross section and UCNC brightness. Although an increased Er3+ concentration reduces ΦUC from ~7% (2% Er3+) to 1% (40%) for 60% Yb3+. Nevertheless, at very high P (> 1 MW/cm2) used for microscopic studies, highly Er3+-doped UCNC display a high brightness because of reduced saturation. These findings underline the importance of synthesis control and will pave the road to many fundamental studies of UC materials.
KW - Upconverion
KW - Nanoparticle
KW - Lanthanides
KW - Quantum yield
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551346
DO - https://doi.org/10.1007/s12274-022-4570-5
SP - 1
EP - 8
PB - Springer
AN - OPUS4-55134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Molecular and nanoscale emitters photophysics , photoluminescence quantum yields, and surface chemistry
N2 - Inorganic nanocrystals such as spectrally shifting lanthanide-based nanoparticles (LnNCs) like NaYF4: Yb, Er and semiconductor quantum dots, organic and inorganic particles stained with sensor molecules, and organic dyes showing aggregation-induced emission are meanwhile broadly applied in the life and material sciences. The identification of optimum particle architectures and molecular structures for photonic applications requires quantitative spectroscopic studies and methods to control and analyse particle surface chemistry. In the following, photoluminescence studies of different emitter classes are presented, thereby addressing the measurement of particle brightness and photoluminescence quantum yields in different spectral windows parameters required for an in-depth mechanistic understanding. In addition, examples for the quantification of surface functional groups on nanomaterials with optical spectroscopy are given.
T2 - GdCH Kolloquium
CY - Düsseldorf, Germany
DA - 11.11.2025
KW - Dye
KW - Fluorescence
KW - Quantum yield
KW - Lifetime
KW - Sensor materials
KW - Temperature
KW - Cr(III) complex
KW - Nano
KW - Particle
KW - Silica
KW - Polymer
KW - Metrology
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - qNMR
KW - Validation
KW - Potentiometry
KW - XPS
PY - 2025
AN - OPUS4-64728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Eckert, J. G.
A1 - Graf, Rebecca T.
A1 - Kunst, A.
A1 - Wegner, Karl David
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Correlating semiconductor nanoparticle architecture and applicability for the controlled encoding of luminescent polymer microparticles
N2 - Luminophore stained micro- and nanobeads made from organic polymers like polystyrene (PS) are broadly used in the life and material sciences as luminescent reporters, for bead-based assays, sensor arrays, printable barcodes, security inks, and the calibration of fluorescence microscopes and flow cytometers. Initially mostly prepared with organic dyes, meanwhile luminescent core/shell nanoparticles (NPs) like spherical semiconductor quantum dots (QDs) are increasingly employed for bead encoding. This is related to their narrower emission spectra, tuneability of emission color, broad wavelength excitability, and better photostability. However, correlations between particle architecture, morphology, and photoluminescence (PL) of the luminescent nanocrystals used for encoding and the optical properties of the NP-stained beads have been rarely explored. This encouraged us to perform a screening study on the incorporation of different types of luminescent core/shell semiconductor nanocrystals into polymer microparticles (PMPs) by a radical-induced polymerization reaction. Nanocrystals explored include CdSe/CdS QDs of varying CdS shell thickness, a CdSe/ZnS core/shell QD, CdSe/CdS quantum rods (QRs), and CdSe/CdS nanoplatelets (NPLs).
Thereby, we focused on the applicability of these NPs for the polymerization synthesis approach used and quantified the preservation of the initial NP luminescence. The spectroscopic characterization of the resulting PMPs revealed the successful staining of the PMPs with luminescent CdSe/CdS QDs and CdSe/CdS NPLs. In contrast, usage of CdSe/CdS QRs and CdSe QDs with a ZnS shell did not yield luminescent PMPs. The results of this study provide new insights into structure–property relationships between NP stained PMPs and the initial luminescent NPs applied for staining and underline the importance of such studies for the performance optimization of NP-stained beads.
KW - Quantitative spectroscopy
KW - Energy transfer
KW - Synthesis
KW - Surface chemistry
KW - Semiconductor quantum dot
KW - Luminescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Lifetime
KW - Quality assurance
KW - Polymer particle
KW - Quantum rod
KW - Nanoplatelet
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602206
DO - https://doi.org/10.1038/s41598-024-62591-1
SN - 2045-2322
VL - 14
SP - 1
EP - 16
AN - OPUS4-60220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rietsch, P.
A1 - Zeyat, M.
A1 - Hübner, Oskar
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Kutter, M.
A1 - Paskin, A.
A1 - Uhlig, J.
A1 - Lentz, D.
A1 - Eigler, S.
T1 - Substitution Pattern-Controlled Fluorescence Lifetimes of Fluoranthene Dyes
N2 - The absorption and emission properties of organic dyes are generally tuned by altering the substitution pattern. However, tuning the fluorescence lifetimes over a range of several 10 ns while barely affecting the spectral features and maintaining a moderate fluorescence quantum yield is challenging. Such properties are required for lifetime multiplexing and barcoding applications. Here, we show how this can be achieved for the class of fluoranthene dyes, which have substitution-dependent lifetimes between 6 and 33 ns for single wavelength excitation and emission. We explore the substitution-dependent emissive properties in the crystalline solid state that would prevent applications.
Furthermore, by analyzing dye mixtures and embedding the dyes in carboxyfunctionalized 8 μm-sized polystyrene particles, the unprecedented potential of these dyes as labels and encoding fluorophores for time-resolved fluorescence detection techniques is demonstrated.
KW - Fluorescence
KW - Label
KW - Fluoranthene
KW - Quantum yield
KW - Reporter
KW - Crystal
KW - Encoding
KW - Multiplexing
KW - Particle
KW - Bead
KW - Lifetime
KW - Dye
KW - Barcoding
PY - 2021
DO - https://doi.org/10.1021/acs.jpcb.0c08851
SN - 1520-5207
VL - 125
IS - 4
SP - 1207
EP - 1213
PB - American Chemical Society
AN - OPUS4-52087
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
A1 - Sander, P.
A1 - Andresen, Elina
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Potentiometric and Optical Titration for Cost- Efficient Quantification of Surface Functional Groups on Silica Nanoparticles
N2 - Surface chemistry of engineered nanomaterials (NMs) plays a critical role not only in determining their interactions with the environment but also in their stability, safety, and functionality across diverse applications ranging from catalysis to biomedicine. Accurate quantification of surface functional groups (FGs) is therefore essential for quality control, risk assessment, and performance optimization.[1] However, many existing analytical techniques are either cost-intensive, require specialized instrumentation, or lack scalability for routine use.
In this study, we present a comparative evaluation of potentiometric and optical titration as two simple, cost-efficient, and automatable methods for quantifying surface functional groups on a variety of surface-modified silica nanoparticles (SiO₂ NPs). These NPs were chosen as they are among the most frequently utilized engineered NMs in the life and material sciences.
Potentiometric titration, based on pH monitoring during acid-base neutralization, offers a direct and label-free approach to determine the total amount of FGs. Optical titration provides a complementary method with potential for high-throughput screening. To examine the accuracy and robustness of our stepwise-optimized workflows and the achievable relative standard deviations (RSDs), measurements were performed by multiple operators in two laboratories. Method validation was conducted through cross-comparison with traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA). A comparison with optical assays highlights the importance of measuring both quantities for comprehensive characterization of surface-modified NMs.[2]
A combined NM surface analysis using optical assays and pH titration will simplify quality control of NM production processes and stability studies, and can yield large datasets for NM grouping in sustainable and safe(r)-by-design studies.
T2 - eMRS Fall Meeting 2025
CY - Warsaw, Poland
DA - 15.09.2025
KW - Fluorescence
KW - Advanced material
KW - Synthesis
KW - Characterization
KW - Nano
KW - Particle
KW - Silica
KW - Surface analysis
KW - Validation
KW - qNMR
KW - Fluram assay
KW - Functional group
KW - Quantification
KW - Potentiometry
KW - Amino groups
KW - Fluorescamine
KW - Calibration
KW - Method comparison
PY - 2025
AN - OPUS4-64205
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saleta Reig, D.
A1 - Grauel, Bettina
A1 - Konyushkin, V. A.
A1 - Nakladov, A. N.
A1 - Federov, P. P.
A1 - Busko, D.
A1 - Howard, I. A.
A1 - Richards, B. S.
A1 - Resch-Genger, Ute
A1 - Kuznetsov, S. V.
A1 - Turshatov, A.
A1 - Würth, Christian
T1 - Upconversion properties of SrF2:Yb3+,Er3+ single
N2 - Synthesis of new upconversion (UC) materials that can convert near-infrared excitation light into visible emission light with high efficiency has crucial importance for energy and bio-applications. Herein, SrF2 single crystals with a doping concentration of 2 mol% Er3+ and 2–8 mol% Yb3+ were synthesized and the optical properties were studied. The absorption cross-section of the different doping ions was calculated. To identify the most efficient and brightest material absolute excitation power dependent UC photoluminescence quantum yields (ϕUC) and brightness values were determined. In addition, excitation characteristics and luminescence lifetimes were analysed to understand the changes in population pathways and possible quenching mechanisms. A dominant two-photon population behaviour of the red and green emission bands was observed for all investigated doping concentrations of Yb3+ and Er3+. The ϕUC value of 6.5% measured using 230 W cm−2 of 976 nm excitation for SrF2 crystal co-doped with 2 mol% Er3+ and 3 mol% Yb3+. These findings broaden the scope of efficient UC materials apart from the record UC material β-NaYF4:Yb3+, Er3+ and provide benchmark values for cubic-phase and especially SrF2- nano and micrometer sized materials.
KW - Luorescence
KW - Upconversion
KW - Crystal
KW - Lanthanide
KW - Quantum yield
KW - Absolute
KW - Lifetime
KW - Er(III)
KW - Quality assurance
KW - Fluorescence standard
KW - SrF2
PY - 2020
DO - https://doi.org/10.1039/c9tc06591a
VL - 8
IS - 12
SP - 4093
EP - 4101
PB - Journal of Materials Chemistry C
AN - OPUS4-50825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Luminescent Nanoparticles – Photophysics, Mechanistic Studies, and Applications
N2 - Inorganic nanocrystals with linear and nonlinear luminescence in the ultraviolet, visible, near infrared and short-wave infrared like semiconductor quantum dots and spectrally shifting lanthanide-based nanophosphors have meanwhile found many applications in the life and material sciences. This includes optical reporters for bioimaging and sensing, security and authentication barcodes, solid state lighting, converter materials, and photovoltaics. The identification of optimum particle structures requires quantitative spectroscopic studies under application-relevant conditions, focusing on the key performance parameter photoluminescence quantum yield, ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods. In this context, methods to quantify the photoluminescence of these different nanoscale emitters are shown and utilized as a basis for a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments. Exemplary for the application potential of such nanomaterials, in addition, the design of optical sensors from different nanomaterials and functional organic dyes is briefly summarized.
T2 - CRC 1411 Symposium
CY - Nürnberg, Germany
DA - 20.03.2023
KW - Semiconductor quantum dot
KW - Upconversion nanocrystal
KW - Luminescence
KW - Quantitative spectroscopy
KW - Photophysics
PY - 2023
AN - OPUS4-57364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Quantifying functional groups and coatings on nanoobjects
N2 - Engineered nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are increasingly used for many key technologies of the 21st century and consumer products. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. Decisive for most applications of NMs are their specific surface properties, which are largely determined by the chemical nature and amounts of ligands and functional groups (FGs) on the NM surface. The surface chemistry can strongly affect the physicochemical properties of NM, their charge, hydrophilicity/hydrophobicity, reactivity, function, stability, and processability and thereby their impact on human health and environment. Knowledge of NM surface chemistry plays an important role for NM functionality and performance in (bio)applications and the fate, exposure, dissolution, transformation, and accumulation of NM, and thus, the potential risks for human health and the environment. This highlights the importance of reliable, validated, and eventually standardized analytical methods for analyzing and quantifying NM surface chemistry for process and quality control of NM production, safe use of NMs, design of novel NM, and sustainable concepts for NM fabrication.[1-3] In this context, interlaboratory comparisons (ILCs) are needed to assess method reliability and reference materials with known surface chemistries for establishing surface analytical methods and their performance validation.[2,4] Also, to respond to the increasing number of samples to be analyzed, cost-efficient automation concepts for surface analysis are needed that can be realized with affordable and preferably commercial instrumentation.[5] Here, we provide an overview of analytical methods for FG analysis and quantification used by us for quantifying broadly utilized FGs and ligands on different types of NMs with electrochemical titration methods, optical assays, nuclear magnetic resonance (NMR) and vibrational (IR) spectroscopy, and X-ray based and thermal analysis methods.[1,2] Thereby, method- and material-related challenges are addressed, and the importance of multi-method characterization approaches easing method validation by method cross-validation. Special emphasis is dedicated to simple, versatile, and cost-efficient methods such as optical assays and electrochemical titration methods.
T2 - eMRS Fall Meeting 2025
CY - Warsaw, Poland
DA - 15.09.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Interlaboratory comparison
KW - Uncertainty
PY - 2025
AN - OPUS4-64183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Godard, A.
A1 - Kalot, G.
A1 - Pliquett, J.
A1 - Busser, B.
A1 - Le Guével, X.
A1 - Wegner, Karl David
A1 - Resch-Genger, Ute
A1 - Russelin, Y.
A1 - Coll, J.-L.
A1 - Denat, F.
A1 - Bodio, E.
A1 - Goze, C.
A1 - Sancey, L.
T1 - Water-Soluble Aza-BODIPYs: Biocompatible Organic Dyes for High Contrast In Vivo NIR-II Imaging
N2 - A simple NIR-II emitting water-soluble system has been developed and
applied in vitro and in vivo. In vitro, the fluorophore quickly accumulated in 2D and 3D cell cultures and rapidly reached the tumor in rodents, showing high NIR-II contrast for up to 1 week. This very efficient probe possesses all the qualities necessary for translation to the clinic as well as for the development of NIR-II emitting materials.
KW - Aza-BODIPY
KW - NIR-II Imaging
KW - In vivo imaging
KW - organic dyes
KW - SWIR
KW - Cancer
KW - Fluorescence
PY - 2020
DO - https://doi.org/10.1021/acs.bioconjchem.0c00175
VL - 31
IS - 4
SP - 1088
EP - 1092
PB - ACS Publications
AN - OPUS4-50695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Assessing different types of silica networks for the complete protection of nir luminescent molecular rubies from oxygen quenching in air
N2 - The application of emerging luminophores such as near-infrared (NIR) emissive earth-abundant chromium(III) (CrIII) complexes and triplet-triplet annihilation upconversion (TTA-UC) systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from luminescence quenching by oxygen. Therefore, we explored the influence of sol-gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles (SiO2 NPs), utilizing the molecular ruby-type luminophores CrPF6 ([Cr(ddpd)2](PF6)3; ddpd = N,N’-dimethyl- N,N’-dipyridin-2-ylpyridin-2,6-diamine) and CrBF4 ([Cr(ddpd)2](BF4)3) with their oxygen-dependent, but polarity-, proticity-, viscosity-, and concentration-independent luminescence as optical probes for oxygen permeability. The sol-gel chemistry routes we assessed include the classical Stöber method and the underexplored larginine approach, which relies on the controlled hydrolysis of tetraethoxysilane (TEOS) in a biphasic cyclohexane/water system with the catalyst l-arginine. As demonstrated by luminescence measurements of air- and argon-saturated dispersions of CrPF6- and CrBF4-stained SiO2 NPs of different size and particle architecture, utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF6 and CrBF4 in acetonitrile (ACN) as benchmarks, only SiO2 NPs or shells synthesized by the l-arginine approach provided complete oxygen protection of the CrIII complexes under ambient conditions. We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings, leading to different oxygen permeabilities. Our l-arginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future.
T2 - eMRS Strasbourg
CY - Strasbourg, France
DA - 26.05.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - NIR
KW - Mechanism
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Oxygen sensing
KW - Surface
KW - Doping
KW - Lifetime
KW - Cr(III) complex
PY - 2025
AN - OPUS4-63300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Güttler, Arne
A1 - Richter, Maria
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - New Reference Materials for the Quantification and Standardization of Fluorescence-based Measurements
N2 - Luminescence techniques are amongst the most commonly used analytical methods in the life and material sciences due to their high sensitivity and non-destructive and multiparametric character. Photoluminescence signals are, however, affected by wavelength-, polarization-, and time-dependent instrument specific effect and the compound-specific photoluminescence quantum yield. The former hamper the comparability of fluorescence measurements, while the relative determination of the latter requires suitable quantum yield standards with well-known photoluminescence quantum yields (QY). For the simple correction of instrument specific effects in the wavelength region of 300 nm to 950 nm, the set of the five certified spectral fluorescence standards BAM-F001 – BAM-F005, has been extended to the NIR range by including two new fluorescence standards currently under certification. For the reliable and accurate determination of QY which is the key performance parameter for the comparison of different luminophores, we certified a set of 12 quantum yield standards, which absorb and emit in the wavelength range from 300 nm to 1000 nm.
T2 - Methods and Applications in Fluorescence
CY - Gothenburg, Sweden
DA - 11.09.2022
KW - Luminescence
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Certified reference material
KW - Standard
PY - 2022
AN - OPUS4-55914
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Getting it right with photoluminescence quantum yields of molecular and nanoscale luminophores and luminescent particles
N2 - Photophysical and mechanistic studies, the comparison of different emitter classes, and the rational design of the next generation of molecular and nanoscale reporters require quantitative photoluminescence measurements and the reliable determination of the key performance parameter photoluminescence quantum yield (QY), i.e., the number of emitted per absorbed photons. This is of special importance for all photoluminescence applications in the life and material sciences in the UV/vis/NIR/SWIR. To improve the reliability and comparability of photoluminescence and QY measurements across laboratories, pitfalls, achievable uncertainties, and material-specific effects related to certain emitter classes must be explored. Also, suitable protocols and reference materials are needed which have been validated in interlaboratory comparisons for different wavelength regions and transparent and scattering luminophores.[1] Based on absolute and relative photoluminescence measurements of functional dyes and nanomaterials like semiconductor quantum dots and rods, spectrally shifting lanthanide upconversion nanocrystals, perovskites, and YAG:Cer converter materials, reliable methods for determining QY of transparent and scattering luminophores, nonlinear emitters, and solid luminescent nanomaterials have been developed.[2,3] Thereby, material- and method-related uncertainties of relative and absolute QY measurements and achievable uncertainties could be quantified for linear and nonlinear UV/vis/NIR/SWIR emitters and lately for also luminescent and scattering materials and solid phoshors, here in an interlaboratory comparison of three labs utilizing integrating sphere spectroscopy.[4,5] In addition, to provide simple tools for a better comparability of QY measurements, recently, a first set of UV/vis/NIR quantum yield standards has been developed and certified with complete uncertainty budgets.[6] In the following, the outcome of these studies will be presented, thereby addressing common pitfalls and providing recommendations on the performance of reliable QY measurements of linear and non-linear emitters in transparent, scattering, and solid samples.
T2 - 29th Lecture Conference on Photochemistry (LCP 2024) GDCh
CY - Mainz, Germany
DA - 16.09.2024
KW - Nanoparticle
KW - Nano
KW - Luminescence
KW - Quality assurance
KW - Synthesis
KW - Standardization
KW - Reference material
KW - Quantum yield
KW - Fluorescence
KW - Reference data
KW - Integrating sphere spectroscopy
KW - ILC
KW - Converter material
KW - YAG:Ce
KW - Optoceramic
PY - 2024
AN - OPUS4-61075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krappe, Alexander R.
A1 - Mayer, Jacob C.
A1 - Zhang, Wuai
A1 - Filla, Lina M.
A1 - Ligorio, Giovanni
A1 - Hermerschmidt, Felix
A1 - Eitelhuber, Larissa S.
A1 - Güttler, Arne
A1 - Weber, Manuela
A1 - Paulus, Beate
A1 - Resch-Genger, Ute
A1 - List-Kratochvil, Emil J.W.
A1 - Eigler, Siegfried
T1 - Highly Emissive Hexa-peri-benzocoronene-fluoranthene Hybrid as Easily Processable and Stable OLED Material
N2 - We report the synthesis of a fluorescent polycyclic aromatic hydrocarbon dye with a “symmetry-broken” core, derived from the related hexa-peri-benzocoronene (HBC) core with fluoranthene subunit. The fluorophore is composed of a pure Carbon skeleton without heteroatoms and exhibits remarkable photo luminescence properties with a photoluminescence Quantum yield (PLQY) of up to 67% in toluene, exceeding that of theparent HBC by a factor of 30. The single crystal X-ray structure reveals the distorted polycyclic aromatic hydrocarbon structure, which is responsible for the optoelectronic properties, as supported by density functional theory calculations. We show that the new fluorescent dye can be readily used for the fabrication of organic light-emitting diodes (OLED) without extensive optimization, whereby solubility in a variety of solvents and successful film formation are decisive.
KW - Quantum Yield
KW - OLED
KW - Fluorescence
KW - Synthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631298
DO - https://doi.org/10.1002/chem.202500742
SN - 1521-3765
SP - 1
EP - 7
PB - John Wiley & Sons, Inc
AN - OPUS4-63129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Solid-State Emissive Aroyl-S,N-Ketene Acetals with Tunable
N2 - N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-Benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation-induced emission characteristics.
Varying the substituent from electron-donating to electronwithdrawing enables the tuning of the solid-state emission Color from deep blue to red.
KW - Nano
KW - Nanoparticle
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - dye
KW - Enhancement
KW - Particle
KW - Polarity
KW - AIE
KW - Aggregation
KW - Aggregation-induced emission
KW - Solid state emission
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509072
DO - https://doi.org/10.1002/anie.201916396
VL - 59
IS - 25
SP - 10037
EP - 10041
PB - Wiley Online Libary
AN - OPUS4-50907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Denißen, M.
A1 - Hannen, R.
A1 - Itskalov, D.
A1 - Biesen, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Reiss, G. J.
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - One-pot synthesis of a white-light emissive bichromophore operated by aggregation-induced dual emission (AIDE) and partial energy transfer
N2 - Merocyanine–triarylamine bichromophores are readily synthesized by sequentially Pd-catalyzed insertion alkynylation–Michael–Suzuki four-component reactions. White-light emissive systems form upon aggregation in 1 : 99 and 0.1 : 99.9 vol% CH2Cl2–cyclohexane mixtures, ascribed to aggregation-induced dual emission (AIDE) in combination with partial energy transfer between both chromophore units as supported by spectroscopic studies.
KW - Energy transfer
KW - Nano
KW - Nanoparticle
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Dye
KW - Enhancement
KW - Particle
KW - Polarity
KW - AIE
KW - Aggregation
KW - Aggregation-induced emission
KW - Solid state emission
KW - Merocyanine
PY - 2020
DO - https://doi.org/10.1039/d0cc03451g
VL - 56
IS - 54
SP - 7407
PB - Royal Society of Chemistry
AN - OPUS4-50936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - May, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Communication of Bichromophore Emission upon Aggregation – Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines
N2 - Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution patterntunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.
KW - Dye
KW - Fluorescence
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531123
DO - https://doi.org/10.1002/chem.202102052
VL - 27
IS - 53
SP - 13426
EP - 13434
PB - Wiley-VCH
AN - OPUS4-53112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, F.
A1 - Fiedler, S.
A1 - Bardan, A.
A1 - Güttler, Arne
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Influence of Measurement Geometry and Blank on Absolute Measurements of Photoluminescence Quantum Yields of Scattering Luminescent Films
N2 - For a series of 500 μm-thick polyurethane films containing different concentrations of luminescent and scattering YAG:Ce microparticles, we systematically explored and quantified pitfalls of absolute measurements of photoluminescence quantum yields (Φf) for often employed integrating sphere (IS) geometries, where the sample is placed either on a sample holder at the bottom of the IS surface or mounted in the IS center. Thereby, the influence of detection and illumination geometry and sample position was examined using blanks with various scattering properties for measuring the number of photons absorbed by the sample. Our results reveal that (i) setup configurations where the scattering sample is mounted in the IS center and (ii) transparent blanks can introduce systematic errors in absolute Φf measurements.
For strongly scattering, luminescent samples, this can result in either an under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf. The size of these uncertainties depends on the scattering properties of the sample and instrument parameters, such as sample position, IS size, wavelength-dependent reflectivity of the IS surface coating, and port configuration. For accurate and reliable absolute Φf measurements, we recommend (i) a blank with scattering properties closely matching those of the sample to realize similar distributions of the diffusely scattered excitation photons within the IS, and (ii) a sufficiently high sample absorption at the excitation wavelength. For IS setups with center-mounted samples, measurement geometries should be utilized that prevent the loss of excitation photons by reflections from the sample out of the IS.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Characterization
KW - Silica
KW - Scattering
KW - Uncertainty
KW - Film
KW - Pphosphor
KW - YAG:Ce
KW - LED
KW - Converter material
KW - Solid material
KW - Polymer
KW - Composite material
KW - Advanced material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638304
DO - https://doi.org/10.1021/acs.analchem.4c06726
SN - 1520-6882
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-63830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Güttler, Arne
T1 - Certified Reference Materials for the Quantification and Standardization of Fluorescence-based Measurements
N2 - The size and shape of photoluminescence signals is affected by wavelength-, polarization-, and time-dependent instrumentspecific contributions and the compound- and environment-specific photoluminescence quantum yield. The former hamper the comparability of fluorescence measurements performed on different measuring devices. The commonly relatively done determination of the performance parameter requires suitable quantum yield standards with well-known. The performance of such measurements is, e.g., described in the written standard IEC 62607 currently revised.
T2 - Colloquium für Optische Spektrometrie 2025
CY - Jena, Germany
DA - 24.09.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Advanced material
KW - Calibration
KW - Characterization
KW - Fluorescence quantum yield
KW - Phosphor
KW - Absolute
KW - Integrating sphere spectroscopy
KW - Dye
KW - Standardization
KW - Reference material
KW - Interlaboratory comparison
KW - Uncertainty
PY - 2025
AN - OPUS4-64213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matiushkina, Anna
T1 - Quantification of Citrate Ligands on the Surface of Nanoparticles
N2 - In this study, different methods for determining nanoparticle surface ligands including thermogravimetric analysis (TGA) are explored to quantify citrate as one of the most popular hydrophilic ligands on the surface of nanoparticles such as iron oxide nanoparticles (IONPs). The purpose of work is to understand which analytical methods are best suited for surface chemistry analysis of citrate stabilized IONPs and to validate these methods.
T2 - SALSA Make and Measure 2024: Interfaces
CY - Berlin, Germany
DA - 11.09.2024
KW - Nano
KW - Particle
KW - Iron oxide
KW - Ligand
KW - Quantification
KW - Advanced material
KW - Surface analysis
KW - Functional group
PY - 2024
AN - OPUS4-62310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Wegner, Karl David
A1 - Kalot, G.
A1 - Busser, B.
A1 - Pliquett, J.
A1 - Köster, U.
A1 - Koll, J. C.
A1 - Denat, F.
A1 - Bodio, E.
A1 - Goze, C.
A1 - Sacey, L.
T1 - NIR aza-BODIPY: a new vector for boron neutron capture therapy (BNCT)
N2 - Boron neutron capture therapy (BNCT) relies on the activation of 10B by thermal neutrons, which results in small highly energetic particle emission inducing cancer cells damage. However, in order to overcome the limits of the currently used BNCT agents, it is necessary to design new systems, which can specifically accumulate and deliver a sufficient amount of 10B in tumors. In this study, we designed a 10B-BSH-containing aza-BODIPY (aza-SWIR-BSH). It enabled the efficient vectorization of clinically used 10B-BSH to the tumor, resulting in higher therapeutic activity than the 10B-BSH alone.
T2 - EMIM 2021
CY - Göttingen, Germany
DA - 24.08.2021
KW - Flourescence
KW - Optical probe
KW - Dye
KW - Photophysics
KW - Quantum yield
KW - Mechanism
KW - NIR
KW - SWIR
KW - Imaging
KW - Method
KW - Quality assurance
KW - BODIPY
KW - Boron Neutron Capture Therapy (BNCT)
KW - Medicine
KW - Life sciences
PY - 2021
AN - OPUS4-53731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Korrosion im Zoo. Kanada in Niedersachsen oder sind Pinguine Inhibitoren?
N2 - Es wird über Schadensfälle an einem komplexen Tiergehege im Zoo Hannover berichtet. Die Schadensursachen werden diskutiert, Abhilfemaßnahmen erläutert und die Umsetzung dargestellt.
T2 - Sitzung gfkorr AK Schadensuntersuchung
CY - Frankfurt am Main, Germany
DA - 30.10.2025
KW - Korosion
KW - Meerwasser
KW - Kathodischer Schutz
PY - 2025
AN - OPUS4-64874
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyerhofer, F.
A1 - Dissinger, F.
A1 - Weigert, Florian
A1 - Jungclaus, J.
A1 - Müller-Caspary, K.
A1 - Waldvogel, S. R.
A1 - Resch-Genger, Ute
A1 - Voss, T.
T1 - Citric Acid Based Carbon Dots with Amine Type Stabilizers: pHSpecific
N2 - We report the synthesis and spectroscopic characteristics of two different sets of carbon dots (CDs) formed by hydrothermal reaction between citric acid and polyethylenimine (PEI) or 2,3-diaminopyridine (DAP). Although the formation of amide-based species and the presence of citrazinic acid type derivates assumed to be responsible for a blue emission is confirmed for both CDs by elemental analysis, infrared spectroscopy, and mass spectrometry, a higher abundance of sp2-hybridized nitrogen is observed for DAP-based CDs, which causes a red-shift of the n-π* absorption band relative to the one of PEI-based CDs. These CD Systems possess high photoluminescence quantum yields (QY) of ∼40% and ∼48% at neutral pH, demonstrating a possible tuning of the optical properties by the amine precursor. pH-Dependent spectroscopic studies revealed a drop in QY to < 9% (pH ∼ 1) and < 21% (pH ∼ 12) for both types of CDs under acidic and basic conditions. In contrast, significant differences in the pHdependency of the n-π* transitions are found for both CD types which are ascribed to different (de)protonation sequences of the CD-specific fluorophores and functional groups using Zeta potential analysis.
KW - Fluorescence
KW - Particle
KW - Nano
KW - Surface group analysis
KW - Carbon dot
KW - C-dot
KW - Fluorescent probe
KW - Quantum yield
KW - Synthesis
KW - IR
KW - MS
KW - Polymer
KW - Ligand
PY - 2020
DO - https://doi.org/10.1021/acs.jpcc.9b11732
VL - 124
IS - 16
SP - 8894
EP - 8904
PB - American Chemical Society
AN - OPUS4-50813
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, T.
A1 - Wang, J.
A1 - Cheng, Z.
A1 - Yang, J.
A1 - Qiao, X.
A1 - Wen, J.
A1 - Resch-Genger, Ute
A1 - Ou, J.
T1 - Fluorescence temperature sensing of NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ nanoparticles at low and high temperatures
N2 - NaYF4:Yb3+/Tm3+@NaGdF4:Nd3+/Yb3+ upconversion nanoparticles (UCNPs) were prepared using a solvothermal method, and the effects of key factors such as the content of sensitiser Nd 3+ and Yb3+ on their luminescence properties were investigated. The nanoparticles are homogeneous in size and well dispersed. Under 808 nm excitation, it can produce strong upconversion fluorescence. At the same time, the nanoparticles have good temperature-sensing properties at the thermally coupled energy levels of 700 nm and 646 nm for Tm3+. Using its fluorescence intensity ratio (FIR), accurate temperature measurements can be performed, and it has been found that it exhibits different temperature sensing properties in low and high-temperature regions. The maximum relative sensitivity was found to be 0.88% K-1 and 1.89% K-1 for the lowtemperature region of 285 K-345 K and the high-temperature region of 345 K-495 K. The nanoparticles were applied to the internal temperature measurement of lithium batteries and the actual high-temperature environment, respectively, and were found to have good temperature measurementt performance.
KW - Fluorescence
KW - Sensor
KW - Temperature
KW - Ratiometric
KW - Lanthanide
KW - Quantum yield
KW - Integrating sphere spectroscopy
KW - Absolute fluorescence
KW - Quality assurance
KW - Nano
KW - Particle
KW - Application
KW - Upconversion nanoparticle
PY - 2022
DO - https://doi.org/10.1088/1361-6528/ac84e4
SN - 1361-6528
VL - 33
IS - 34
SP - 1
EP - 15
PB - IOP Publishing
CY - Bristol
AN - OPUS4-55454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oskoei, Parastu
T1 - Thermoresponsive UCNP@MSN Nanoparticles for Doxorubicin Delivery in Melanoma Cells
N2 - Upconversion nanoparticles (UCNPs) possess unique photophysical characteristics, such as excita bility by near infrared (NIR) light, which facilitates deep tissue penetration, multi color emission , long luminescence lifetimes, and an excellent photostability. These features have made UCNPs promising tools for biomedical applications . M esoporous silica nanoparticles (MSNs) functionalized with stimuli responsive nanovalves or specific coatings enable the encapsulation and controlled release of therapeutic agen ts, thereby offering spatiotemporal precision in drug delivery 1 3 ]]. Among drug delivery strategies, photoresponsive systems have attracted growing attention due to their potential for clinical applications . This is especially relevant for melanoma, an aggressive skin cancer with increasing global incidence, for which conventional therapeutic modalities remain largely insufficient in advanced stage 4 In this work, core shell UCNP@MSN nanoparticles were synthetised by coating UCNPs with a mesoporous silica layer, which was subsequently functionalized with thermoresponsive retro Diels Alder nanovalves [ and loaded with the chemotherapeutic agent doxorubicin (DOX). Controlled drug release was effectively achieved under 980 nm NIR i llumination . Treatment with functionalized nanoparticles significantly reduced the viability of melanoma cell lines, with an enhanced cytotoxicity being observed upon combined nanoparticle exposure and NIR illumination . Mechanistic analyses revealed that neither UCNPs nor NIR i llumination alone could induce the production of reactive oxygen species (ROS); however, their combination induced a marked increase in ROS levels in two of the three tested cell lines. Furthermore, this dual treatment promoted substantial apoptotic and/or necrotic responses across all cell models. These findings underscore the potential of UCNP@MSN nanoplatforms, equipped with thermoresponsive ga tes , as efficient photoactivated drug delivery systems for melanoma therapy.
T2 - Conference Jornadas CICECO
CY - Aveiro, Portugal
DA - 09.10.2025
KW - Nano
KW - Particle
KW - Lanthanide
KW - Upconversion
KW - Surface chemistry
KW - Mesoporous silica
KW - Doxorubicin
KW - Nanomedicine
KW - Triggered release
KW - pH
KW - Cellular uptake
KW - Toxicity
KW - Folate
KW - Ligand
PY - 2025
AN - OPUS4-64371
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Quantifying the total and accessible amount of surface functionalities and ligands on nanomaterials
N2 - Engineered nanomaterials (NMs) of various chemical composition and surface functionalization are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NM dispersibility, stability, processability, and function as well as the interaction with biological species and environmental fate are largely determined by NM surface functionalities, i.e., functional groups (FGs) and ligands. Therefore, reliable, reproducible, and eventually standardized surface characterization methods are vital for quality control of NMs, and mandatory to meet increasing concerns regarding their safety.
Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods.[1] The latter less costly and fast methods, which can be automated, are often used by NM producers for process and quality control.[1,2] To validate methods, establish measurement uncertain-ties, test reference materials, and produce reference data, multi-method characterization studies are needed.[3,4] as well as interlaboratory comparisons (ILC) on determining NM surface chemistry and well characterized test and reference NMs providing benchmark values.[5,6] Here, we present examples for quantifying common surface FGs such as amino and carboxyl groups on functional NMs of different chemical composition such as silica, polymer, iron oxide, and lanthanide-based upconversion nanoparticles with optical assays, electrochemical titration methods, qNMR, and chromatographic separation techniques. In addition, ongoing interlaboratory comparisons will be presented.
T2 - Yucomat 2025
CY - Herec Novi, Montenegro
DA - 01.09.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Interlaboratory comparison
KW - Uncertainty
PY - 2025
AN - OPUS4-64182
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Measurements of Photoluminescence Quantum Yields of Scattering LED Converter Materials
N2 - How to Get it Right with the Absolute Measurement of Photoluminescence Quantum Yields of Scattering LED Converter Materials Saskia Fiedler+,a, Florian Frenzel+,a, Christian Würth a, Isabella Tavernaro a, Michelle Grüne c, Stefan Schweizer c,d, Axel Engel e, and Ute Resch-Genger a* a Division Biophotonics, Federal Institute for Materials Research and Testing (BAM), Richard-Willstaetter-Strasse 11, D-12489 Berlin, Germany; email: ute.resch@bam.de b Present address: Photonic Materials, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands c Faculty of Electrical Engineering, South Westphalia University of Applied Sciences, Lübecker Ring 2, 59494, Soest, Germany d Fraunhofer Application Center for Inorganic Phosphors, Branch Lab of Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Lübecker Ring 2, 59494, Soest, Germany e Schott AG Technical Services, Hattenbergstrasse 10, D-55122 Mainz, Germany Optical measurements of scattering materials such as luminescent nano- and microparticles and phosphors dispersed in liquid and solid matrices play an important role in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. A key performance parameter is the photoluminescence quantum yield QY, i.e., the number of emitted per number of absorbed photons. QY of transparent luminophore solutions can be obtained relative to a fluorescence QY standard of known QY, meanwhile available as certified reference materials.[1] The determination of QY of scattering liquid and solid samples like nanoparticle dispersions, phosphors, and optoceramics requires, however, absolute measurements with an integrating sphere setup. Despite the need for reliable absolute QY measurements, no interlaboratory comparison (ILCs) on measurement uncertainties has been performed and scattering standards with known QY are not available. We present the results of an ILC of 3 labs from academia and industry on measurements of transparent and scattering dye solutions and solid phosphors and converter materials like YAG:Ce optoceramics with commercial stand-alone integrating sphere setups of different illumination and detection geometries. Special emphasis was dedicated to the influence of measurement geometry, optical properties of the blank for determining the number of incident photons absorbed by the sample, and sample-specific surface roughness. Matching QY values could be obtained for transparent dye solutions and scattering dispersions with a blank with scattering properties closely matching those of the sample, QY measurements of optoceramic samples with different blanks revealed substantial differences of more than 20 %. Based on our data, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder as blanks.
T2 - eMRS
CY - Strasbourg, France
DA - 26.05.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - NIR
KW - Characterization
KW - Electron microscopy
KW - Film
KW - Integrating sphere spectroscopy
KW - Calibration
KW - Lifetime
KW - Advanced materials
KW - LED converter
KW - YAG:Ce
KW - ILC
KW - Measurement uncertainty
KW - Absolute quantum yield
PY - 2025
AN - OPUS4-63327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Development of multimodal methods to quantify the total and accessible number of functional groups and ligands on nanomaterials
N2 - Engineered and tailored nanomaterials (NM) are of great interest in the life and material sciences, as they can be used, e.g., as drug carriers, barcodes, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. Their performance and safety depend not only on their particle size, size distribution, and morphology, but also on their surface chemistry, i.e., the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. It also underlines the importance of validated analytical methods that provide accurate information on these application-relevant physicochemical properties with a known uncertainty. In the case of FG quantification, this calls for robust, fast, inexpensive, and reliable methods which allow for the characterization of a broad variety of NM differing in size, chemical composition, and optical properties.
Methods
Aiming at the development of simple, versatile, and multimodal tools for the quantification of bioanalytically relevant FG such as amine, carboxy, thiol, and aldehyde functionalities, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance (NMR), mass spectrometry (MS), and thermal analysis methods.
Results
Here, we will present examples for different types of NMs and FGs including results from a currently running interlaboratory comparison (ILC) with the National Research Council of Canada (NRC) to pave the road for method standardization.
Innovative aspects
• Surface analysis
• Performance and safety of nanomaterials
• Standardization
T2 - ANAKON 2023
CY - Vienna, Austria
DA - 11.04.2023
KW - Engineered Nanomaterials
KW - Surface group analysis
KW - Optical spectroscopy
KW - Quantitative NMR
KW - Ligands
KW - Dye
KW - Particle synthesis
KW - Optical Assays
KW - Titration
KW - Safe-by-Design
KW - Nano
KW - Nanosafety
KW - Silica- and Polystyrene Particles
PY - 2023
AN - OPUS4-59127
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rezvani, A.
A1 - Wang, Z.
A1 - Wegner, Karl David
A1 - Soltanmoradi, H.
A1 - Kichigin, A.
A1 - Zhou, X.
A1 - Gantenberg, T.
A1 - Schram, J.
A1 - Zubiri, B. A.
A1 - Spiecker, E.
A1 - Walter, J.
A1 - Resch-Genger, Ute
A1 - Segets, D.
T1 - Separation of Indium Phosphide/Zinc Sulfide Core−Shell Quantum Dots from Shelling Byproducts through Multistep Agglomeration
N2 - Semiconductor quantum dots (QDs) possess unique electronic and optical properties, making them promising candidates for applications in lightemitting diodes, solar cells, bioimaging, and photocatalysis. Precise control over their size, shape, and chemical and electronic structure is crucial to ensure the desired functional properties and optimize device performance. However, challenges in QD synthesis and post-synthesis modification persist, especially in large-scale production. This study addresses the classification of QDs synthesized in a tubular flow reactor consisting of a mixture of the desired InP/ZnS core−shell QDs and QDs made from the shell material, i.e., here ZnS QDs formed as a byproduct during the formation step of the ZnS shell. The homogeneous nucleation of ZnS nanoparticles from the shelling material introduces a heterogeneity in size and composition and affects the optical properties of the resulting QDs. To address this issue, we developed a size-selective agglomeration (SSA) technique by incrementally introducing ethanol as a poor solvent and classified the synthesized QDs into 13 distinct fractions. These 13 fractions are sorted into three distinct groups: (i) larger InP/ZnS QDs, (ii) a combination of smaller InP/ZnS QDs and larger ZnS QDs, and (iii) predominant ZnS QDs with some very tiny InP/ZnS QDs. The comprehensive characterization of the fractions was conducted using UV−visible absorption spectroscopy, photoluminescence spectroscopy, high-resolution scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, total reflection X-ray fluorescence, and analytical ultracentrifugation. We could demonstrate that our method effectively separated unwanted ZnS QDs from the target InP/ZnS QDs. In addition, the fractions enriched in smaller InP/ZnS QDs exhibited a higher photoluminescence quantum yield compared to the fractions with larger QDs. This demonstrates the efficacy of SSA in finetuning the composition of QD mixtures produced on a larger scale to improve their functional properties. This approach provides fundamental understanding toward the development of a scalable two-dimensional classification process for such ultrasmall nanoparticles by particle size and composition.
KW - Quality assurance
KW - Reference material
KW - Nano
KW - Particle
KW - Quantum dot
KW - Synthesis
KW - Flow reactor
KW - InP
KW - Shell
KW - ZnS
KW - Surface chemistry
KW - Method
KW - Fluorescence
KW - Quantum yield
KW - TEM
PY - 2025
DO - https://doi.org/10.1021/acsnano.4c18530
SN - 1936-086X
VL - 19
IS - 20
SP - 19080
EP - 19094
PB - ACS Publications
AN - OPUS4-63215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oskoei, Párástu
T1 - Cell mechanisms induced by doxorubicin-loaded UCNP@MSN nanoparticles with a thermosresponsive nanovalve in melanoma cells
N2 - Upconversion nanoparticles (UCNPs) exhibit several remarkable optical properties, including excitation by near infrared (NIR) light, which enables deep tissue penetration, multiple distinct emission bands across a wide range of wavelengths, long luminescen ce lifetimes, and high photostability. These features make them particularly attractive for various biomedical applications. Mesoporous silica nanoparticles (MSNs), functionalized with nanovalves or specific coatings, have been explored for controlled and targeted drug delivery, where therapeutic agents are encapsulated within the nanopores, allowing spatiotemporal release 1 3 ]]. Among the promising approaches, photoactivated drug delivery systems have drawn considerable interest due to their versatility and potential. One relevant application is in the treatment of melanoma, an aggressive form of skin cancer with a rising global incidence. In advanced stages, conventional therapies often fail to achieve complete tumour eradication, resulting in poor prognose s 4 In this study, UCNPs were coated with a mesoporous silica shell to form core shell UCNP@MSN nanoparticles, which were further functionalized with thermoresponsive retro Diels Alder nanovalves and loaded with doxorubicin (DOX), a chemotherapeutic drug used in melanoma treatment. Upon exposure to 980 nm NIR light, DOX release was successfully triggered in the culture medium. Exposure to functionalized UCNPs decreased the viability of the tested melanoma cell lines, with further reductions observed when the ex posure to the nanoparticles was combined with irradiation. Subsequently, t he toxicity mechanisms were evaluated and showed that w hile individual treatments with either the functionalized UCNPs or NIR irradiation alone had no effect on reactive oxygen species (ROS) production, their combination significantly increased ROS levels in two of the three tested cell lines. This combined treatment also led to notable increases in apoptotic , necrotic or both type of cells’ percentages on all cell lines. Overall, these findings highlight the potential of these nanoparticles with thermoresponsive gating mechanisms as effective platforms for targeted drug delivery in melanoma therapy.
T2 - EUROTOX 2025
CY - Athens, Greece
DA - 14.09.2025
KW - Nano
KW - Particle
KW - Lanthanide
KW - Upconversion
KW - Surface chemistry
KW - Mesoporous silica
KW - Doxorubicin
KW - Nanomedicine
KW - Triggered release
KW - pH
KW - Cellular uptake
KW - Toxicity
KW - Folate
KW - Ligand
PY - 2025
AN - OPUS4-64372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Forschung in einer Bundesoberbehörde wie der BAM
N2 - Die Bundesanstalt für Materialforschung und -prüfung (BAM) ist eine forschende Bundesoberbehörde und Einrichtung der Ressortforschung der Bundesrepublik Deutschland. Unter ihrer Leitlinie „Sicherheit in Technik und Chemie“ ist sie zuständig für die öffentliche technische Sicherheit und für metrologische Aufgaben in der Chemie. Das Aufgabenspektrum der BAM, das sich an aktuellen Fragestellungen aus Wissenschaft, Wirtschaft, Politik und Normung orientiert, bietet sehr viele interessante Tätigkeitsfelder für Naturwissenschaftler*Innen und Ingenieur*Innen.
T2 - WIFO Leipzig 2023
CY - Leipzig, Germany
DA - 05.09.2023
KW - Quality assurance
KW - Optical spectroscopy
KW - Certification
KW - Reference product
KW - Integrating sphere spectroscopy
KW - Fluorescence
KW - Quantum yield
KW - Reference material
KW - Reference data
KW - Traceability
KW - Nano
KW - Particle
KW - Analytical chemistry
KW - Sensor
KW - Safety
PY - 2023
AN - OPUS4-58397
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - pH- and O2-Responsive Nanoparticles – The MiGraGen Project
N2 - In recent years, the demand for reliable, versatile, fluorescent pH and oxygen sensors has increased rapidly in many biomedical applications since these analytes are important indicators of cell function or certain diseases. Therefore, sensor particles are needed that are small enough to penetrate cells, non-toxic, and allow for close-up optical monitoring. When developing such sensor systems, one must consider the pH and oxygen range detectable by the sensor dye and the matrix material of the used carrier particles. Here, we present the development of pH- and oxygen-responsive polymeric beads functionalized with fluorescent dyad molecules that consist of an analyte-responsive fluorophore and an analyte-inert dye.
T2 - MiGraGen Project Meeting 09.08.2023
CY - Online Meeting
DA - 09.08.2023
KW - Nano- and microsensors
KW - Functionalized silica and polymeric particles
KW - pH sensing
KW - Oxygen sensing
KW - Fluorescence
PY - 2023
AN - OPUS4-58071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Krenzer, J.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
A1 - Müller, Th. J. J.
T1 - Asymmetrically bridged aroyl-S,N-ketene acetalbased multichromophores with aggregationinduced tunable emission
N2 - Asymmetrically bridged aroyl-S,N-ketene acetals and aroyl-S,N-ketene acetal multichromophores can be readily synthesized in consecutive three-, four-, or five-component syntheses in good to excellent yields by several successive Suzuki-couplings of aroyl-S,N-ketene acetals and bis(boronic)acid esters. Different aroyl-S,N-ketene acetals as well as linker molecules yield a library of 23 multichromophores with substitution and linker pattern-tunable emission properties. This allows control of different communication pathways between the chromophores and of aggregation-induced emission (AIE) and energy transfer (ET) properties, providing elaborate aggregation-based fluorescence switches.
KW - Dye
KW - Aggregation
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Sythesis
KW - Nanaoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550719
DO - https://doi.org/10.1039/d2sc00415a
VL - 13
SP - 5374
EP - 5381
PB - Royal Society of Chemistry
AN - OPUS4-55071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Soares, J. X.
A1 - Wegner, Karl David
A1 - Ribeiro, D. S. M.
A1 - Melo, A.
A1 - Häusler, I.
A1 - Santos, J. L. M.
A1 - Resch-Genger, Ute
T1 - Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control
N2 - In the blossoming field of Cd-free semiconductor quantum dots (QDs), ternary I–III–VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water, their high photoluminescence (PL) Quantum yields (QYs) in the red and near infrared (NIR) region, and their inherently low toxicity. Moreover, their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL lifetime. To overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties, we assessed and modelled the synthesis of high-quality MPA-capped AgInS2/ZnS (AIS/ZnS) QDs. Systematically refined Parameters included reaction time, temperature, Ag:In ratio, S:In ratio, Zn:In ratio, MPA:In ratio, and pH using a design-of-experiment approach.
Guidance for the optimization was provided by mathematical models developed for the application-relevant PL parameters, maximum PL wavelength, QY, and PL lifetime as well as the elemental composition in terms of Ag:In:Zn ratio. With these experimental data-based models, MPA:In and Ag:In ratios and pH values were identified as the most important synthesis parameters for PL Control and an insight into the connection of these parameters could be gained. Subsequently, the experimental conditions to synthetize QDs with tunable emission and high QY were predicted. The excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AIS/ZnS QDs with defined PL features.
This approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs.
KW - Modelling
KW - Nanoparticle
KW - AIS
KW - Semiconductor quantum dot
KW - Design of experiment
KW - Photoluminescence
KW - Quantum yield
KW - Surface chemistry
KW - Synthesis
KW - Lifetime
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510075
DO - https://doi.org/10.1007/s12274-020-2876-8
VL - 13
IS - 9
SP - 2438
EP - 2450
PB - Springer
AN - OPUS4-51007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kage, Daniel
A1 - Hoffmann, Katrin
A1 - Borcherding, H.
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Lifetime encoding in flow cytometry for bead‑based sensing of biomolecular interaction
N2 - To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis, clinical diagnostics, and optically encoded bead-based assays, we performed a proof-of-principle study to detect biomolecular interactions utilizing fluorescence lifetime (LT)-encoded micron-sized polymer beads bearing target-specific bioligands and a recently developed prototype lifetime flow cytometer (LT-FCM setup). This instrument is equipped with a single excitation light source and different fluorescence detectors, one operated in the photon-counting mode for time-resolved measurements of fluorescence decays and three detectors for conventional intensity measurements in different spectral windows. First, discrimination of bead-bound biomolecules was demonstrated in the time domain exemplarily for two targets, Streptavidin (SAv) and the tumor marker human chorionic gonadotropin (HCG). In a second step, the determination of biomolecule concentration levels was addressed representatively for the inflammation-related biomarker tumor necrosis factor (TNF-α) utilizing fluorescence intensity measurements in a second channel of the LT-FCM instrument. Our results underline the applicability of LT-FCM in the time domain for measurements of biomolecular interactions in suspension assays. In the future, the combination of spectral and LT encoding and multiplexing and the expansion of the time scale from the lower nanosecond range to the longer nanosecond and the microsecond region is expected to provide many distinguishable codes. This enables an increasing degree of multiplexing which could be attractive for high throughput screening applications.
KW - Fluorescence
KW - Sensor
KW - Assay
KW - Protein
KW - Multiplexing
KW - Flow cytometry
KW - Barcoding
KW - Lifetime
KW - Dye
KW - Bead
KW - Bead-based assay
KW - Method
KW - Quantification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516007
DO - https://doi.org/10.1038/s41598-020-76150-x
VL - 10
IS - 1
SP - 19477
PB - Nature
AN - OPUS4-51600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Katrin
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
T1 - Fluorescence calibration standards made from broadband emitters encapsulated in polymer beads for fluorescence microscopy and flow cytometry
N2 - We present here the design and characterization of a set of spectral calibration beads. These calibration beads are intended for the determination and regular control of the spectral characteristics of fluorescence microscopes and other fluorescence measuring devices for the readout of bead-based assays. This set consists of micrometer-sized polymer beads loaded with dyes from the liquid Calibration Kit Spectral Fluorescence Standards developed and certified by BAM for the wavelength-dependent Determination of the spectral responsivity of fluorescencemeasuring devices like spectrofluorometers. To cover the wavelength Region from 400 to 800 nm, two new near-infrared emissive dyes were included, which were spectroscopically characterized in solution and encapsulated in the beads. The resulting set of beads presents the first step towards a new platform of spectral calibration beads for the determination of the spectral characteristics of fluorescence instruments like fluorescence microscopes, FCM setups, and microtiter plate readers, thereby meeting the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas, e.g., medical diagnostics. This will eventually provide the basis for standardized calibration procedures for imaging systems as an alternative to microchannel slides containing dye solutions previously reported by us.
KW - Fluorescence standard
KW - Fluorescence
KW - Dye
KW - Microscopy
KW - Bead
KW - Particle
KW - NIR
KW - calibration
KW - Quality assurance
KW - Traceability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508117
DO - https://doi.org/10.1007/s00216-020-02664-y
SN - 1618-2642
VL - 412
IS - 24
SP - 6499
EP - 6507
PB - Springer
AN - OPUS4-50811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rietsch, P.
A1 - Sobottka, S.
A1 - Hoffmann, K.
A1 - Popov, A. A.
A1 - Hildebrandt, P.
A1 - Sarkar, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - Between Aromatic and Quinoid Structure: A Symmetrical UV to Vis/NIR Benzothiadiazole Redox Switch
N2 - Reversibly switching the light absorption of organic molecules by redox processes is of interest for applications in sensors, light harvesting, smart materials, and medical diagnostics. This work presents a symmetrical benzothiadiazole (BTD) derivative with a high fluorescence quantum yield in solution and in the crystalline state and shows by spectroelectrochemical analysis that reversible switching of UV absorption in the neutral state, to broadband Vis/NIR absorption in the 1st oxidized state, to sharp band Vis absorption in the 2nd oxidized state, is possible.
For the one-electron oxidized species, formation of a delocalized radical is confirmed by electron paramagnetic resonance spectroelectrochemistry. Furthermore, our results reveal an increasing quinoidal distortion upon the 1st and 2nd oxidation, which can be used as the leitmotif for the development of BTD based redox switches.
KW - Dye
KW - Electrochemistry
KW - Switch
KW - Redox
KW - Sensor
KW - Photophysics
KW - Quantum yield
KW - photoluminescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517222
DO - https://doi.org/10.1002/chem.202004009
VL - 26
IS - 72
SP - 17361
EP - 17365
PB - Wiley-VCH GmbH
AN - OPUS4-51722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Deumer, J.
A1 - Andresen, Elina
T1 - SAXS data of bipyramidal LiYF4 nanoparticles
N2 - SAXS data of bipyramidal LiYF4 nanoparticles synthesized by the Federal Institute for Materials Research and Testing (BAM) and measured by the Physikalisch-Technische Bundesanstalt (PTB) at the synchrotron facility Bessy II, Berlin, Germany.
KW - Reference data set
KW - Simulation
KW - Reference material
KW - Upconversion nanoparticles
KW - Particle number concentration
KW - SAXS
PY - 2024
DO - https://doi.org/10.5281/zenodo.13691409
PB - Zenodo
CY - Geneva
AN - OPUS4-62134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matiushkina, Anna
T1 - Quantification of Hydrophilic Surface Ligands on Nanoparticles
N2 - The rapid development of nanotechnology is driven by a wide range of possible applications of nanoparticles (NPs) depending on their functions and composition, for example, in biomedicine, energy harvesting, and optoelectronics. Due to the large surface-to-volume ratio of nanoparticles, their properties and function are often highly dependent on surface chemistry, which also determines their stability and interaction with the environment. To ensure the successful advancement of nanomaterials in biomedical applications as well as in material sciences, it is hence crucial to develop reliable methods to control and quantify ligand molecules and functional groups on the NP surface for different NP processing steps including ligand exchange and the subsequent functionalization with, e.g., antifouling agents and recognition moieties. These methods must then be validated and eventually standardized. This also calls for suitable reference materials with known surface chemistries or functionalities.
Methods for determining and quantifying surface functional groups and NP capping ligands include quantitative nuclear magnetic resonance (qNMR) techniques, thermogravimetric analysis (TGA), mass spectrometric (MS) methods, high-performance liquid chromatography (HPLC), and optical assays with photometric and/or fluorometric readout.[1] In the focus of this study on ligand exchange and quantification are differently sized iron oxide nanoparticles (IONPs), already used in biomedicine with applications as magnetic resonance imaging (MRI) contrast agents or for magnetic hyperthermia. IONPs can be prepared by a high temperature synthesis in nonpolar solvents, resulting in a superior monodispersity and crystallinity compared to particles prepared by aqueous synthesis methods. Such IONPs bear, however, hydrophobic surface ligands, that need to be exchanged for hydrophilic molecules to ensure water dispersibility required for biomedical applications. For these applications, a complete removal of potentially toxic surface ligands remaining from IONP synthesis is crucial. Here, we will present the synthesis of differently sized spherical IONPs capped with hydrophobic oleic acid molecules and an in-depth study of the ligand exchange to hydrophilic molecules such as citrate. We assessed the size, size distribution, and colloidal stability of the IONPs utilizing transmission electron microscopy (TEM), dynamic light scattering (DLS), and Zeta potential measurements before and after ligand exchange. In addition, several approaches to ligand quantification have been explored involving a variety of analytical tools. Our ultimate goal is here to identify the optimal methods for ligand analysis and to develop schemes for method validation, via the comparison of analytical techniques relying on different principles of signal generation (method cross-validation).
T2 - E-MRS 2024 SPRING MEETING
CY - Strasbourg, France
DA - 27.05.2024
KW - Nano
KW - Particle
KW - Iron oxide
KW - Ligand
KW - Quantification
KW - Advanced material
KW - Surface analysis
KW - Functional group
PY - 2024
AN - OPUS4-62296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zou, Q.
A1 - Marcelot, C.
A1 - Ratel-Ramond, N.
A1 - Yi, X.
A1 - Roblin, P.
A1 - Frenzel, Florian
A1 - Resch-Genger, Ute
A1 - Eftekhari, A.
A1 - Bouchet, A.
A1 - Coudret, C.
A1 - Verelst, M.
A1 - Chen, X.
A1 - Mauricot, R.
A1 - Roux, C.
T1 - Heterogeneous Oxysulfide@Fluoride Core/ Shell Nanocrystals for Upconversion-Based Nanothermometry
N2 - Lanthanide (Ln3+)-doped upconversion nanoparticles (UCNPs) often suffer from weak luminescence, especially when their sizes are ultrasmall (less than 10 nm). Enhancing the upconversion luminescence (UCL) efficiency of ultrasmall UCNPs has remained a challenge that must be undertaken if any practical applications are to be envisaged. Herein, we present a Ln3+-doped oxysulfide@fluoride core/shell heterostructure which shows efficient UCL properties under 980nm excitation and good stability in solution. Through epitaxial heterogeneous growth, a ∼4 nm optically inert β-NaYF4 shell was coated onto ∼5 nm ultrasmall Gd2O2S:20%Yb,1%Tm. These Gd2O2S:20%Yb,1%Tm@NaYF4 core/shell UCNPs exhibit a more than 800-fold increase in UCL intensity compared to the unprotected core, a 180-fold increase in luminescence decay time of the 3H4 → 3H6 Tm3+ transition from 5 to 900 μs, and an upconversion quantum yield (UCQY) of 0.76% at an excitation power density of 155 W/cm2. Likewise, Gd2O2S:20%Yb,2%Er@NaYF4 core/shell UCNPs show a nearly 5000-fold
increase of their UCL intensity compared to the Gd2O2S:20%Yb,2%Er core and a maximum UCQY of 0.61%. In the Yb/Er core−shell UCNP system, the observed variation of luminescence intensity ratio seems to originate from a change in lattice strain as the temperature is elevated. For nanothermometry applications, the thermal sensitivities based on thermally coupled levels are estimated for both Yb/Tm and Yb/Er doped Gd2O2S@NaYF4 core/shell UCNPs.
KW - Upconversion nanoparticle
KW - Nanosensor
KW - Lanthanide
KW - Surface coating
KW - Quantum yield
KW - Photophysic
PY - 2022
DO - https://doi.org/10.1021/acsnano.2c02423
SN - 1936-0851
SP - 1
EP - 11
PB - ACS Publications
AN - OPUS4-55440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Simon, Fabian
A1 - Gehrenkemper, Lennart
A1 - Tobias, Charlie
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
T1 - Quantification of the amount of surface groups of aminated silica nano- and microparticles utilizing a fluorine tag and HR-CS-GFMAS
N2 - The performance, bioavailability, and safe use of engineered nanomaterials (NMs) depends not only on properties such as size, shape, and surface area, but largely on surface chemistry. While many sizing methods have been established, there is still a lack of validated screening methods for determining NM surface functional groups (FGs). In this context, we present a fast and simple method for FG quantification using high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) and assess its applicability for the surface analysis of representatively chosen aminated silica nanoparticles (NPs) and microparticles (MPs) in conjunction with amino FG labeling with a fluorine tag. For this proof-of-concept study, first surface amino FG screening of the silica NPs and MPs was done with a potentiometric back titration method, providing the total amount of protonatable surface FGs, and two optical assays relying on reporter dyes with sizes and spatial requirements, i.e., surface binding areas smaller or larger than that of the fluorine tag to estimate the maximum and reporter-accessible number of amino FGs. Subsequently, the surface amino FGs were labeled with the fluorine tag 4-(trifluoromethyl)benzoic acid (TFMB) and the amount of fluorine originating from the bound TFMB molecules was quantified by HR-CS-GFMAS in two common organic solvents, i.e., dimethyl sulfoxide (DMSO) or ethanol (EtOH) to assess possible interferences from organic matrices. Our study revealed limits of detection (LODs) and quantification (LOQs) for fluorine of 1.0 µg/L and 3.5 µg/L in EtOH and 1.5 µg/L and 5.0 µg/L in DMSO, respectively. Overall, a quick and simple method for analyzing surface FGs on NPs and MPs was presented utilizing broadly available fluorine tags and HR-CS-GFMAS for fluorine quantification, which can be applied, e.g., for homogeneity, stability, and aging studies of surface-modified particles. This could contribute to ease the understanding of property-safety relationships for surface-functionalized NMs.
KW - Fluorine Analysis
KW - Nano- and microparticles
KW - Surface group quantification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641965
DO - https://doi.org/10.1007/s00216-025-06107-4
SN - 1618-2642
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-64196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Oskoei, Párástu
T1 - Effects of upconversion nanoparticles with a thermo-responsive nanovalve loaded with doxorubicin in melanoma cells
N2 - Melanoma skin cancer has an increasingly higher incidence , and w hen detected in advanced stages, tumour eradication is often incomplete, contributing to poor prognosis with conventional treatments. Upconversion nanoparticles (UCNPs) have unique properties, such as excitability under near infrared (NIR) excitation light, which confers a relatively high penetration depth in tissue that allow their effective use in several biomedical applications Mesoporous silica nanoparticles (MSN) with nanovalves or derived coatings have widely been used for triggered and targeted drug delivery in the past. Anticancer drugs can be loaded into the pores of MSN, enabling controlled drug release. In this work, UCNPs were coated with a mesoporous silica shell yielding UCNP@MSN core shell nanoparticles which were equipped with thermoresponsive retro Diels Alder nanovalves and then loaded with DOX , a chemotherapeutic agent for melanoma treatmen t (UCNP@MSN DOX) Subsequent DOX release from this drug delivery system was triggered by 980 nm NIR light. Melanoma cells exposed to UCNP@MSN DOX or the NIR laser exhibited no change in ROS production , while the combination of both induced an increase in ROS production. This combination of conditions also induced changes on apoptosis and necrosis levels. These findings underscore the potential use of UCNP @MSN drug delivery systems with thermoresponsive caps as effective drug delivery platforms for melanoma therapy.
T2 - VII iBiMED Symposium
CY - Aveiro, Portugal
DA - 23.05.2025
KW - Nano
KW - Particle
KW - Lanthanide
KW - Upconversion
KW - Surface chemistry
KW - Mesoporous silica
KW - Doxorubicin
KW - Nanomedicine
KW - Triggered release
KW - pH
KW - Cellular uptake
KW - Toxicity
KW - Folate
KW - Ligand
PY - 2025
AN - OPUS4-64373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Resch-Genger, Ute
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
T1 - Extending Certified Spectral Fluorescence Standards for the Calibration and Performance Validation of Fluorescence Instruments to the NIR – Closing the Gap from 750 nm to 940 nm with Two Novel NIR Dyes
N2 - Fluorescence methods provide spectral, intensity, polarization, and lifetime information, which contain sample- and instrument-specific contributions. Fluorescence data, comparable across instruments and laboratories, require validated calibration procedures and certified fluorescence standards.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
SP - 1
EP - 4
PB - Springer Nature
CY - London
AN - OPUS4-62739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
A1 - Walter, J.
T1 - Size-resolved emission properties of core/shell CdSe/CdS quantum dots via multiwavelength emission analytical ultracentrifugation
N2 - Colloids provide manifold opportunities for targeted product design due to their tunable properties with respect to size, shape, composition, surface, and spectral characteristics. However, the determination of structure-property relationships is quite challenging as most particulate samples exhibit polydispersity of their disperse properties. Analytical ultracentrifugation (AUC) is a fractionating technique and highly accurate method for the multidimensional analysis of nanoparticles as it permits the differentiation of spectral information linked to hydro- and thermodynamic properties of the particles.
So far, characterization capabilities for fluorescent nanoparticles by AUC were limited, as the formerly commercially available fluorescence detector could not provide any spectral information. Using a multiwavelength emission detector developed in our group, it is possible to extract spectra of fluorescent particles and biomolecules alongside their sedimentation and diffusion coefficients within a single centrifugation experiment.
In our contribution, we will highlight that even narrowly distributed core/shell CdSe/CdS quantum dots still show size- and structure-dependent shifts of their fluorescence spectra, which can be resolved with our AUC system in an ensemble measurement. Thereby, we can link spectral changes of only a few nanometers to particle sizes retrieved with Angstrom size resolution. Single-particle measurements not only supported the results obtained with the AUC system but also provided deeper insights into the photophysical processes of individual QDs, clearly demonstrating the complementary nature of the techniques used. With our novel multiwavelength emission detector and the established extinction-based detector for AUC, a comprehensive platform for the holistic characterization of fluorescent colloids is now available.
T2 - 26th International Analytical Ultracentrifugation Symposium
CY - Bad Staffelstein, Germany
DA - 24.07.2024
KW - Quantum dots
KW - Analytical ultracentrifugation
KW - Reference materials
KW - Calibrated fluorescence measurements
KW - Size-resolved emission
PY - 2024
AN - OPUS4-60814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andreato, E.
A1 - Panov, N.
A1 - Artiga, A.
A1 - Osipova, Viktoriia
A1 - Resch-Genger, Ute
A1 - Ximendes, E.
A1 - Molina, P.
A1 - Canton, P.
A1 - Marin, R.
T1 - Indium-Based Fluoride Nanoparticles Doped with Chromium for Near-Infrared Luminescence
N2 - Transition metal (TM) and rare earth (RE) ion-doped nanoparticles (NPs) are photoluminescent materials of technological relevance in bioimaging, sensing, and light conversion. Fluoride NPs are particularly attractive in this context, since they combine low-energy phonons, high chemical stability, optical transparency, size, and architecture tunability. Yet, nearly all reported colloidal fluoride NPs (e.g., NaYF4 and LiYF4) can only be efficiently doped with RE3+ and not with luminescent TM ions. Herein, we contribute to filling this gap in materials science by reporting Na3InF6 NPs doped with Cr3+ as a model luminescent TM ion. We unveil the heat-driven NP formation mechanism, which involves a cubic-to-monoclinic phase conversion, similarly to the cubic-tohexagonal phase conversion in NaYF4. Reaction temperatures above 225 °C and reaction time have a limited impact on the NP morphology, while the amount of fluoride precursor and oleylamine grants control over the NP size. After verifying that Na3InF6 NPs show negligible cytotoxicity toward U-87 cell line, we study the optical properties of these NPs upon Cr3+ doping.
Temperature-dependent photoluminescence measurements indicate that Cr3+ ions experience a weak crystal field in the Na3InF6 host lattice, while their photoluminescence lifetime varies linearly in the 20−50 °C range. These results set the ground for further studies of photoluminescent TM-doped fluoride NPs, toward their applications in bioimaging, sensing, and light-converting devices.
KW - Quality assurance
KW - Fluorescence
KW - Traceability
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - NIR
KW - Mechanism
KW - Characterization
KW - XRD
KW - Phase transition
KW - Ligand
KW - Surface
KW - Doping
KW - Lifetime
PY - 2025
DO - https://doi.org/10.1021/acs.chemmater.4c03335
SN - 1520-5002
SP - 1
EP - 14
PB - American Chemical Society
AN - OPUS4-63073
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matiushkina, Anna
T1 - Quantification of Citrate Ligands on Nanoparticle Surfaces
N2 - To ensure the successful advancement of nanomaterials (NM) in applications and their safe use, it is crucial to develop reliable methods to control and quantify ligands and functional groups (FG) on the nanoparticle (NP) surface as surface chemistry largely determines the interactions of NPs with their surroundings. Many analytical methods can be used for this purpose. However, their applicability strongly depends on the type of NM and ligand(s) and most of them require challenging protocols for sample preparation, i.e., the removal of the NPs or their dissolution, which can influence the accuracy of the measurements. While some methods allow the precise quantification of specific ligands such as quantitative nuclear magnetic resonance (qNMR), others provide only semi-quantitative results like Fourier Transform infrared spectroscopy (FTIR) or target more general analyte groups like thermogravimetric analysis (TGA) detecting mass losses (total organic content) or conductometry (e.g., (de)protonable FGs such as carboxyl or amine groups). [1] The calculation of the coverage of the NP surface with ligands, additionally requires knowledge of their total surface area, which can be obtained, e.g., from a precise characterization of NP size and concentration.
Citrate is one of the most frequently utilized surface ligand for stabilizing metal, metal oxide, and lanthanide-based upconversion NPs in hydrophilic environments. However, its quantification on NP surfaces has rarely been addressed although it is a frequent analyte in medical or food analysis. In this study we compare several methods for quantifying citrate as capping ligands of iron oxide NPs (IONPs), exemplarily chosen because of their broad applications in the life science. [2] The size of the IONPs was characterized by electron microscopy (EM) and dynamic light scattering (DLS), while their concentration was determined by quantifying iron ions after acidic particle dissolution using a colorimetric assay and inductively coupled plasma optical emission spectroscopy (ICP-OES). The simplest approach for citrate quantification, direct photometric UV-detection after acidic digestion of the IONPs, yielded only reasonable results when combined with reversed phase high-performance liquid chromatography (HPLC). These results were cross validated with qNMR that required the development of a reliable sample preparation protocol addressing not only particle dissolution in deuterated solvents but also the removal of the paramagnetic iron ions interfering with NMR measurements. Comparison with results from TGA gives insight into the sensitivity and specificity of these methods and their potential for quantifying surface ligands on NPs.
T2 - Anakon 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Advanced material
KW - Functional group
KW - Iron oxide
KW - Ligand
KW - Nano
KW - Particle
KW - Quantification
KW - Surface analysis
PY - 2025
AN - OPUS4-64861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
T1 - AIFRI - Artificial Intelligence for Rail Inspection
N2 - Verlegte Eisenbahnschienen werden mit Schienenprüfzügen, die mit zerstörungsfreier Ultraschall- und Wirbelstromprüftechnik ausgerüstet sind, auf Schienenfehler geprüft. Im Rahmen des mFund-geförderten Projektes AIFRI wurden von der TU Berlin KI-Algorithmen entwickelt, die die Prüfer bei der Auswertung der Daten unterstützen. Felddaten von realen Prüffahrten sind für das Training der KI ungeeignet, da es einerseits kaum Defekte in den Schienen gibt, die sich mit Ultraschall detektieren lassen, andererseits bei der Wirbelstromprüfung zahlreiche Oberflächeneffekte unbekannter Ursache angezeigt werden. Die Aufgabe der BAM bestand darin, durch Simulation gelabelte Trainingsdaten für die KI zu generieren.
Während die mit simulierten Daten trainierte KI bei der Ultraschallprüfung eine gute Performance aufweist, sofern der Sim2Real-Gap durch Addition realitätsnaher Rauschsignaturen zu den simulierten Trainingsdaten minimiert wird, erwies sich die verwendete KI bei der Wirbelstromprüfung aufgrund zu vieler Falsch-Positives als ungeeignet. Die Ursache liegt vermutlich darin, dass aufgrund der großen Vielfalt von teils unbekannten Oberflächeneffekten nur eine kleine Auswahl simuliert werden konnte und die KI bei untrainierten Signalsignaturen halluziniert.
T2 - AI/ML Symposium
CY - Berlin, Germany
DA - 06.11.2025
KW - Artificial intelligence
KW - Non-destructive testing
KW - Ultrasonic testing
KW - Eddy current testing
KW - Simulation
KW - Sim2real gap
KW - Railway rail inspection
PY - 2025
AN - OPUS4-64630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mente, Tobias
T1 - Gasflaschenzerknall in einer Löschanlage: Ursachen – Schadensanalyse – Prävention
N2 - Schadensanalyse an einer mit Inergen gefüllten Gasflasche aus einer Löschanlage aus dem vergütetem Stahl 34CrMo4. Die Durchführung der Schadensanalyse erfolgte nach VDI 3822. Schadensursache war Spannungsrisskorrosion durch Wasserreste in Verbindung mit dem Gasbestandteil Kohlendioxid des eingefüllten Inergen. Die Wasserreste verblieben nach der hydraulischen Druckprüfung unentdeckt in der 1996 hergestellten Gasflasche. Auch bei der Erstbefüllung mit Inergen im Jahr 2003 blieben die Wasserreste unentdeckt. Nach Installation der befüllten Gasflasche in der Löschanlage im Jahr 2004 verblieb diese dort bis zum Schadensereignis im Jahr 2021.
T2 - 51. VDI-Jahrestagung Schadensanalyse - Produktverbesserung durch Schadensprävention
CY - Würzburg, Germany
DA - 21.10.2025
KW - Gasflasche
KW - Inergen-Löschanlage
KW - Schadensanalyse
PY - 2025
AN - OPUS4-64652
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Machine Learning and Thermography as Tools for Local Porosity Prediction in AM of Metals
N2 - Quality assurance of metal additive manufacturing (PBF-LB/M) is still a challenge. Offering deep process insights, thermography is a well-suited monitoring technique. Here, we show how machine learning based on thermographic data enables a local part porosity prediction.
T2 - Laser Applications Conference (LAC)
CY - Prague, Czech Republic
DA - 19.10.2025
KW - PBF-LB/M
KW - In situ monitoring
KW - Thermography
KW - Additive Manufacturing
KW - Process monitoring
KW - Porosity prediction
KW - Machine Learning
KW - Feature extraction
PY - 2025
AN - OPUS4-64669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Towards sustainable solution-driven recycling of gypsum
N2 - Calcium sulfate hemihydrate (CaSO4ᐧ0.5H2O), also known as bassanite, has been used as a precursor to produce gypsum (dihydrate, CaSO4ᐧ2H2O) for various construction and decorative purposes since prehistoric times. The main route to obtain hemihydrate is a thermal treatment of gypsum at temperatures typically between 150 °C and 200 °C to remove some of the structural water. In this contribution, we introduce (Fig. 1) a more efficient and sustainable method (T < 100 °C) that enables the direct, rapid, and reversibly conversion of gypsum to bassanite using reusable high salinity aqueous solutions (brineswith c[NaCl] > 4 M). The optimum conditions for the efficient production of bassanite in a short time (< 5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the typical behaviour of the bassanite phase in low salt environments. Traditionally, hemihydrate is obtained through a solid state thermal treatment because bassanite is considered to be metastable with respect to gypsum and anhydrite in aqueous solutions, and therefore gypsum-to-bassanite conversion should not occur in water. Its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures is inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline structure for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios.
T2 - RAL-SAS - UK Small angle scattering meeting 2025
CY - Oxford, United Kongdom
DA - 16.06.2025
KW - Scattering
KW - SAXS
KW - Calcium sulfate
KW - Gypsum
PY - 2025
AN - OPUS4-64682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Y.
A1 - Ulbricht, Alexander
A1 - Schmidt, F.
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Schwitalla, A.D.
T1 - Micro-CT analysis and mechanical properties of low dimensional CFR-PEEK specimens additively manufactured by material extrusion
N2 - Material extrusion of thermoplastic polymers enables the realization of complex specific designs with high performance composites. The present study aims at evaluating the mechanical properties of carbon fiberreinforced semi-crystalline thermoplastic polymer polyether ether ketone (CFR-PEEK) manufactured by material extrusion and correlating them with results obtained by micro-CT. Samples in the shape of small bars were provided by Kumovis (Munich, Germany). The determination of surface roughness and density was followed by three-point bending tests. To reveal the pore distribution as well as the fusion quality of CFR PEEK when applied with external forces, micro-CT scans were performed with an X-ray microscope before and after the mechanical test to localize the sites where the fracture is generated. The density of CFR-PEEK bars indicated that they had superior mechanical properties compared with our previous study on unfilled 3D printed PEEK (bending modulus: (5.4 ± 0.5) GPa vs. (1.05 ± 0.05) GPa to (1.48 ± 0.10) GPa; bending strength: (167 ± 11) MPa vs. (51 ± 15) to (193 ± 7) MPa). Micro-CT analyses revealed the local 3D-distribution of voids. Voids of 30 μm diameter are nearly spherical and make up the main part of the total porosity. The larger the voids, the more they deviate from a spherical shape. Significant lack-of-fusion voids are located between the deposited filaments. By growing and merging, they act as seeds for the forming fracture line in the region of the flexural specimens where the maximum local tensile stresses occurred under bending load. Our work provides a detailed analysis of printed PEEK with fiber additive and relates this with mechanical properties.
KW - CFR-PEEK
KW - Material extrusion (MEX)
KW - FFF
KW - Surface topography
KW - Bending property
KW - Micro-CT
PY - 2023
DO - https://doi.org/10.1016/j.jmbbm.2023.106085
SN - 1751-6161
VL - 146
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-58112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Soares, A.P.
A1 - Baum, D.
A1 - Hesse, B.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Zaslansky, P.
T1 - Scattering and phase-contrast X-ray methods reveal damage to glass fibers in endodontic posts following dental bur trimming
N2 - Objectives. There is concern that the integrity of fiberglass dental posts may be affected by chairside trimming during treatment. We hypothesize that hard X-ray methods of phase contrast-enhanced micro-CT (PCE-CT) and synchrotron based X-ray refraction (SXRR) can reliably identify and help characterize the extent of damage.
Methods. Fiberglass posts were imaged both as manufactured and following trimming with a diamond bur. Each of the posts was imaged by SXRR and by PCE-CT. Datasets from PCE-CT were used to visualize and quantify 2D and 3D morphological characteristics of intact and of damage-affected regions caused by trimming. Results. The SXRR images revealed fiber inhomogeneities from manufacturing with a significant increase in internal surfaces in sample regions corresponding to damage from trimming. PCE-CT volumes unveiled the micromorphology of single fibers in the posts and some damage in the trimmed area (e.g. fractures, splinters and cracks). Area, perimeter, circularity, roundness, volume and thickness of the glass fibers in the trimmed area were statistically different from the control (p < 0.01).
Significance. The integrity of single fibers in the post is critical for bending resistance and for long-term adhesion to the cement in the root canals. Damage to the fibers causes substantial structural weakening across the post diameter. Glass fragments produced due to contact with the dental bur may separate from the post and may significantly reduce bond capacity. The above mentioned synchrotron-based imaging techniques can further facilitate assessment of the structural integrity and the appearance of defects in posts (e.g. after mechanical load).
KW - Fiberglass composite
KW - Fiber reinforced dental post
KW - X-ray refraction
KW - Phase contrast-enhanced micro-CT
KW - Non-destructive testing
PY - 2021
DO - https://doi.org/10.1016/j.dental.2020.10.018
SN - 0109-5641
VL - 37
IS - 2
SP - 201
EP - 211
PB - Elsevier Inc.
AN - OPUS4-52071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bauer, L. J.
T1 - Complementary X-ray techniques reveal hidden details in teeth
N2 - Within the DFG project ‘IXdent’, first results have been achieved on 2D µXRF and X-ray refraction radiography measurements as well as combined 3D confocal µXRF and µXCT investigations at the interface between filling and bovine tooth tissue. The benefit of multiple analytical techniques and the combination of structural and elemental analysis will be demonstrated.
T2 - HZB User Meeting 2021
CY - Online meeting
DA - 09.12.2021
KW - Dental materials
KW - X-ray refraction
KW - Computed tomography
KW - X-ray fluorescence
PY - 2021
AN - OPUS4-54094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Engelking, Lorenz
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Effect of heat control on mechanical properties and residual stresses at the transition zone of component and substrate in hybrid DED‑arc manufacturing
N2 - In hybrid additive manufacturing, components or semi-finished products manufactured by conventional primary forming are enhanced or modified by additive manufactured structures. However, systematic investigations focusing on the critical transition area between the specific properties of the substrate (like high-strength) and the additively manufactured component, made of specific filler material, are still lacking. The focus of the present study was to determine the influence of heat control on the Δt8/5 cooling time, the distortion, the mechanical properties, and the residual stresses in the transition area of hybrid-additive components. This contributed to the knowledge regarding the safe avoidance of cold cracking, excessive distortion, a reduction in yield stress, and the implementation of hybrid DED-arc manufacturing. The heat control was varied by means of heat input and working temperature such that the Δt8/5 cooling times corresponded to the recommended processing range. The heat input has a greater influence on the cooling time in the transition area than the working temperature. Working temperature and the total energy applied per layer have a significant effect on component distortion. The lowest working temperature of 100 °C in combination with the highest total energy per layer leads to significantly greater distortion compared to manufacturing with a high working temperature of 300 °C and low total energy per layer. In addition, the longitudinal residual compressive stresses in the sensitive transition area are reduced from − 500 MPa to approx. − 200 MPa by adjusting the working temperature from 100 to 300 °C. Such complex interactions must be clarified comprehensively to provide users with easily applicable processing recommendations and standard specifications for an economical hybrid additive manufacturing of components made, for example, of high-strength steels in the transition area.
T2 - IIW Annual Assembly and International Conference
CY - Rhodes Island, Greece
DA - 07.07.2024
KW - Hybrid additive manufacturing
KW - DED-arc
KW - Heat control
KW - High-strength metals
KW - Residual stress
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630415
DO - https://doi.org/10.1007/s40194-025-02036-z
SN - 1878-6669
SP - 1
EP - 15
PB - Springer
AN - OPUS4-63041
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Stawski, Tomasz
A1 - Miliute, Aiste
T1 - Structural Refinement of ZrV₂O₇ with Negative Thermal Expansion Using Pair Distribution Function Analysis
N2 - This repository contains Python scripts specifically developed for structural refinement of Zirconium Vanadate (ZrV₂O₇), a material known for its negative thermal expansion (NTE). The scripts implement Pair Distribution Function (PDF) analysis to refine crystal structures directly from experimental X-ray diffraction (XRD) data. The refinement workflow is built around the DiffPy-CMI library, enhanced with custom functionalities tailored for ZrV₂O₇ and similar oxide materials.
KW - Zirconium vandate
KW - Total scattering
KW - Pair distribution function
KW - Structure refinement
PY - 2025
DO - https://doi.org/10.5281/zenodo.15395752
PB - Zenodo
CY - Geneva
AN - OPUS4-64750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hälsig, André
A1 - Eßbach, Tim-Bernd
A1 - Scharf-Wildenhain, Ronny
A1 - Altobelli, Martin Gabriel
A1 - Phadnis, Prathamesh Jayant
A1 - Hensel, Jonas
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Armansyah,
T1 - Qualitätssicherung beim Lichtbogenschweißen
N2 - Der fortschreitende Trend der Automatisierung und Dokumentation sowie die wirtschaftliche und technische Optimierung von Fügeaufgaben machen es notwendig, Sensoren zielführend in bestehende und vorhandene Anlagentechnik zu integrieren. Jedoch bietet die reine Datenerfassung alleine nur einen geringen Mehrwert. Erst durch eine optimierte Datenspeicherung, eine intelligente sowie automatische Datenauswertung und -bewertung entsteht ein echter Nutzen für den industriellen Anwender.
Zur Qualifizierung einer standardisierbaren Herangehensweise der Qualitätssicherung beim Lichtbogenschweißen wurden mit einer nationalen Arbeitsgruppe bestehende Unstetigkeiten der Qualitätsbeeinflussung geschweißter Bauteile aufgeschlüsselt und definiert. Parallel dazu wurde ein automatisiertes Schweißsystem mit hochgenauer Messtechnik (u. a. Stromstärke, Spannung, Drahtvorschub, Thermokamera, Geometriescanner usw.) ausgerüstet und validiert. Hierfür wurde die Open-Source-Technologie WelDX der BAM genutzt. Anschließend wurden bewusst fehlerhaft geschweißte Nähte im Vergleich zu fehlerfreien Referenzschweißungen hergestellt, Messdaten erfasst und analysiert. Im Rahmen dieses Beitrags werden erste Ergebnisse und Erkenntnisse in Bezug auf die Detektion und Bewertung von Unstetigkeiten beim Lichtbogenschweißen dargestellt. Dabei wurde deutlich, dass alternative Darstellungs- und Analysemethoden wie die Anwendung der Mahalanobis-Distanz im Stromstärke-Spannungs-Diagramm eine eindeutigere Korrelation zwischen Unstetigkeiten und Prozesssignalen ermöglichen.
T2 - DVS CONGRESS 2025
CY - Essen, Germany
DA - 16.09.2025
KW - Lichtbogenschweißen
KW - Qualitätssicherung
KW - Forschungsdatenmanagement
KW - WelDX
PY - 2025
SN - 978-3-96144-298-0
VL - 401
SP - 76
EP - 85
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-64565
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simón Muzás, Juan
T1 - Mitigation of liquation cracking in laser welding of pairs of L-PBF processed and wrought plates of Inconel 718
N2 - Laser welding is an appropriate technique for joining Laser Powder Bed Fusion (L-PBF) parts together and to conventional wrought ones. The potential consists of profiting from synergies between additive and conventional manufacturing methods and overcoming the existing limitations of both. On the one hand, L-PBF is a widely spread metal-based additive manufacturing technique suitable for generating complex parts which can present intrinsic designed cavities, conformal cooling channels, and filigree structures contributing to sustainable manufacturing and efficiency-oriented designs. On the other hand, chamber sizes for producing L-PBF parts are limited, and the process is time-consuming. Thus, its employment is not for every geometry justified. Additionally, they are in most cases individual elements of a larger assembly and need to be joined together to conventionally fabricated parts.
The present research suggests laser welding parameters to adequately bond pairs of wrought and L-PBF processed plates and two L-PBF plates of Inconel 718 in butt position. L-PBF samples are printed in three different build-up orientations. Additionally, the influence of as-built L-PBF roughness qualities and usual pre-weld preparations such as edge milling are examined. The effect of normed pre-weld heat treatments is also contemplated. Identified cracks are analyzed by means of EDS in order to confirm the present phases on the areas of interest. EBSD is also employed to obtain a clear depiction of the crystallographic texture and distribution of the hot cracks.
The quality of the weldment was examined according to existing standards. Substantial differences in seam geometry and microstructure across different edge’s surface qualities and build directions of stress relieved L-PBF parts have not been detected. Nevertheless, even if no other irregularities are present in the seam, variability in liquation cracking susceptibility has been confirmed. This defect is prone to happen when parts made of this nickel-based superalloy are welded together when not enough precautions are taken. It has been determined that grain size and ductility of the material before welding play a crucial role and mitigating or intensifying these imperfections. Moreover, recommendations are presented to avoid this potential welding defect.
T2 - International Welding Conference
CY - Tokyo, Japan
DA - 17.07.2022
KW - Hybrid Part
KW - Liquation Cracking
KW - Build-up Orientation
KW - Pre-weld Preparation
KW - Heat Treatment
KW - Selective Laser Melting (SLM)
KW - Inconel 718
KW - Laser Powder Bed Fusion (L-PBF)
KW - Laser Welding (LW)
PY - 2022
AN - OPUS4-55515
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cao, L.
A1 - Thome, P.
A1 - Agudo Jácome, Leonardo
A1 - Somsen, C.
A1 - Cailletaud, G.
A1 - Eggeler, G.
T1 - On the influence of crystallography on creep of circular notched single crystal superalloy specimens
N2 - The present work contributes to a better understanding of the effect of stress multiaxiality on the creep behavior of single crystal Ni-base superalloys. For this purpose we studied the creep deformation and rupture behavior of double notched miniature creep tensile specimens loaded in three crystallographic directions [100], [110] and [111] (creep conditions: 950 °C and 400 MPa net section stress). Crystal plasticity finite element method (CPFEM) was used to analyze the creep stress and strain distributions during creep. Double notched specimens have the advantage that when one notch fails, the other is still intact and allows to study a material state which is close to rupture. No notch root cracking was observed, while microstructural damage (pores and micro cracks) were frequently observed in the center of the notch root region. This is in agreement with the FEM results (high axial stress and high hydrostatic stress in the center of the notched specimen). Twinning was observed in the notch regions of [110] and [111] specimens, and <112> {111} twins were detected and analyzed using orientation imaging scanning electron microscopy. The present work shows that high lattice rotations can be detected in SXs after creep fracture, but they are associated with the high strains accumulated in the final rupture event.
KW - Single crystal Ni-Base superalloys
KW - Double notched creep specimen
KW - Stress distribution
KW - Lattice rotation
KW - Cracks
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506060
DO - https://doi.org/10.1016/j.msea.2020.139255
SN - 0921-5093
VL - 782
SP - 139255
PB - Elsevier B. V.
AN - OPUS4-50606
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan-Scherb, Christiane
A1 - Menneken, Martina
A1 - Weber, Kathrin
A1 - Agudo Jácome, Leonardo
A1 - Nolze, Gert
T1 - Elucidation of orientation relations between Fe-Cr alloys and corrosionproducts after high temperature SO2 corrosion
N2 - The early stages of corrosion of Fe-Cr-model alloys (2 and 9 % Cr) were investigated after exposure at 650 °C in0.5 % SO2containing gas by electron backscattered diffraction (EBSD) and transmission electron microscopy(TEM). The impact of the grain orientation of the base alloy on the orientation relations of the corrosion productsis presented. After 2 min–5 min exposure the formation of a multi-layered corrosion zone was discovered. Aclear orientation relationship between ferrite and the (Fe,Cr)3O4 spinel could be demonstrated. The obtainedresults show the importance of the grain orientation on oxidation resistance.
KW - Iron
KW - TEM
KW - SEM
KW - High temperature corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508911
DO - https://doi.org/10.1016/j.corsci.2020.108809
VL - 174
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-50891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, F.
A1 - Cheng, J.
A1 - Liang, S. B.
A1 - Ke, C. B.
A1 - Cao, S. S.
A1 - Zhang, X. P.
A1 - Zizak, I.
A1 - Manzoni, Anna Maria
A1 - Yu, J. M.
A1 - Wanderka, N.
A1 - Li, W.
T1 - Formation and evolution of hierarchical microstructures in a Ni-based superalloy investigated by in situ high-temperature synchrotron X-ray diffraction
N2 - Hierarchical microstructures are created when additional γ particles form in γ’ precipitates and they are linked to improved strength and creep properties in high-temperature alloys. Here, we follow the formation and evolution of a hierarchical microstructure in Ni86.1Al8.5Ti5.4 by in situ synchrotron X-ray diffraction at 1023 K up to 48 h to derive the lattice parameters of the γ matrix, γ’ precipitates and γ particles and misfits between phases. Finite element method-based computer simulations of hierarchical microstructures allow obtaining each phase's lattice parameter, thereby aiding peak identification in the in situ X-ray diffraction data. The simulations further give insight into the heterogeneous strain distribution between γ’ precipitates and γ particles, which gives rise to an anisotropic diffusion potential that drives the directional growth of γ particles. We rationalize a schematic model for the growth of γ particles, based on the Gibbs-Thomson effect of capillary and strain-induced anisotropic diffusion potentials. Our results highlight the importance of elastic properties, elastic anisotropy, lattice parameters, and diffusion potentials in controlling the behavior and stability of hierarchical microstructures.
KW - XRD
KW - Superalloy
KW - Finite element method
KW - Transmission electron microscopy
PY - 2022
DO - https://doi.org/10.1016/j.jallcom.2022.165845
SN - 0925-8388
VL - 919
SP - 1
EP - 17
PB - Elsevier
CY - Lausanne
AN - OPUS4-55394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kingsbery, Phillip
A1 - Stephan-Scherb, Christiane
T1 - Effect of KCl deposits in high‐temperature corrosion on chromium‐rich steels in SO2‐containing atmosphere
N2 - High‐temperature corrosion was studied under multiple chemical loads on ferritic‐austenitic model alloys (Fe–13Cr, Fe–18Cr–12Ni, and Fe‐25Cr–20Ni) with KCl deposit under 0.5% SO2/99.5% Ar gas atmosphere at 560°C. Postexposure characterization was done by X‐ray diffraction and scanning electron microscopy. In a pure SO2/Ar environment a protective Cr2O3 scale was formed by all samples. The introduction of KCl deposits causes the scale to be nonprotective and multilayered, consisting of CrS, FeS, Cr2O3, Fe3O4, and Fe2O3. The impact of the microstructure and alloying elements is discussed.
KW - High‐temperature corrosion
KW - KCl
KW - Microstructure
KW - SO2
KW - Steel alloy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543056
DO - https://doi.org/10.1002/maco.202112901
VL - 73
IS - 5
SP - 758
EP - 770
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54305
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Dubois, F.
A1 - Mousa, M. S.
A1 - von Schlippenbach, C.
A1 - Többens, D. M.
A1 - Yesilcicek, Yasemin
A1 - Zaiser, E.
A1 - Hesse, René
A1 - Haas, S.
A1 - Glatzel, U.
T1 - On the Formation of Eutectics in Variations of the Al10Co25Cr8Fe15Ni36Ti6 Compositionally Complex Alloy
N2 - Superalloy inspired Al10Co25Cr8Fe15Ni36Ti6 compositionally complex alloy is known for its gamma-gamma' microstructure and the third Heusler phase. Variations of this alloy, gained by replacing 0.5 or 1 at. pct Al by the equivalent amount of Mo, W, Zr, Hf or B, can show more phases in addition to this three-phase morphology. When the homogenization temperature is chosen too high, a eutectic phase formation can take place at the grain boundaries, depending on the trace elements: Mo and W do not form eutectics while Hf, Zr and B do. In order to avoid the eutectic formation and the potential implied grain boundary weakening, the homogenization temperature must be chosen carefully by differential scanning calorimetry measurements. A too low homogenization temperature, however, could impede the misorientation alignment of the dendrites in the grain. The influence of grain boundary phases and incomplete dendrite re-orientation are compared and discussed.
KW - High entropy alloy
KW - Eutectic
KW - Homogenization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543504
DO - https://doi.org/10.1007/s11661-020-06091-7
VL - 52
IS - 1
SP - 143
EP - 150
PB - Springer
AN - OPUS4-54350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bettge, Dirk
T1 - Ergebnisse eines Ringversuchs zur quantitativen Analyse von Schwingstreifen auf Bruchflächen metallischer Werkstoffe
N2 - Die Frage nach der Anzahl der Lastspiele bis zum Bruch eines Bauteils wird in der Schadensanalyse oft gestellt – und kann meistens gar nicht oder nicht mit befriedigender Sicherheit beantwortet werden. Selbst wenn ein duktiler Werkstoff vorliegt, der unter schwingender Beanspruchung prinzipiell Schwingstreifen ausbilden kann, ist nicht sicher, ob diese vollzählig erkannt werden können und ob jeder Schwingstreifen auf einem Lastspiel beruht. Im Arbeitskreis Fraktographie wurde ein Ringversuch durchgeführt, bei dem an Bruchflächen und an Bildern dieser Bruchflächen Schwingstreifenabstände bestimmt werden sollten. Insgesamt 70 Teilnehmer/innen aus Industrie und Forschung haben daran teilgenommen. Die aufgebrachten Lastspielzahlen und Rissfortschritte lagen vor, waren den Teilnehmern aber nicht bekannt. Obwohl diese überwiegend erfahrene Fachkräfte sind, waren die Streuungen der Ergebnisse unerwartet groß. Es wird diskutiert, woran das liegt und wie die Situation verbessert werden kann.
T2 - DGM Metallographietagung 2025
CY - Bochum, Germany
DA - 08.10.2025
KW - Fraktographie
PY - 2025
AN - OPUS4-64344
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dávila, Josué
A1 - Kleba-Ehrhardt, Rafael
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Influence Of Initial Powder Oxidation Level On Process-induced Material Degradation During The Laser Powder Bed Fusion Of Nickel-based Haynes 282
N2 - This study examines the impact of varying oxidation levels in nickel-based Haynes 282 powder on particle degradation during laser powder bed fusion (PBF-LB|M). Four powder batches with oxygen content levels of approximately from 140 ppm to1400 ppm were processed using PBF-LB|M. A powder collection container was fabricated to sample unmelted powder from heat-affected regions of the powder bed. Recoating and melting proceeded without issues; however, increased fume emissions were observed at higher oxidation levels, indicating intensified spatter formation. Post-process analysis revealed that finer particles exhibited greater surface oxidation due to their higher surface-to-volume ratio. Despite significant oxygen uptake, chemical analysis showed no measurable changes in key alloying elements in either the unmelted or spatter particles. Additionally, changes in particle size distribution became more pronounced at high oxidation levels. These findings provide a basis for understanding oxidation-driven degradation and optimizing powder reuse strategies to maintain material performance.
T2 - Euro Powder Metallurgy 2025 Congress & Exhibition
CY - Glasgow, United Kingdom
DA - 14.09.2025
KW - Recycling
KW - Additive manufacturing
KW - Laser powder bed fusion (PBF-LB/M)
KW - Powder quality
KW - Powder degradation
KW - Powder oxidation
KW - Spatter particles
KW - Particles ejected
KW - Powder reuse
PY - 2025
DO - https://doi.org/10.59499/EP256767986
SP - 1
EP - 9
PB - EPMA
AN - OPUS4-64369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poka, Konstantin
A1 - Ali, Sozol
A1 - Ulbricht, Alexander
A1 - Schröder, Jakob
A1 - Khambayat, Jiganesh
A1 - Scholz, Maik
A1 - Saeed, Waleed
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Reduction of extraneous variance in powder bed fusion with laser beam of metals by means of advanced digital preprocessing
N2 - Data-driven quality assurance and reproducibility are critical for advancing the industrial maturity of Powder Bed Fusion with Laser Beam of Metals (PBF-LB/M). This study addresses the extraneous variance in scan vectors that arises even for identical cross sections of nominally identical components but located at different positions on the build platform. This inherent variance, common across most PBF-LB/M machines, is caused by scan vector computation relative to the machine coordinate origin and subsequent projection of the resulting pattern onto individual component cross sections. In this work, scan vectors are computed still following conventional slicing, but relative to the workpiece origin of each component, using an EOS M 300-4. This digital preprocessing approach homogenizes fabrication conditions, ensuring that anomalies, such as scan vector overlaps, occur consistently across identical components. The impact during fabrication is assessed through powder bed imaging, melt pool monitoring, and operational data from the multilaser PBF-LB/M machine. Components are manufactured from AlSi10Mg for each scan vector computation origin and subsequently qualified using x-ray computed tomography, optical coordinate measurement, and optical surface measurement. A comprehensive evaluation is conducted, comparing the results in terms of component density, geometric accuracy, and surface roughness to those obtained using conventional preprocessing. Based on these findings, practical recommendations are provided, focusing on achieved quality criteria to identify potential drawbacks, while also considering the life cycle analysis of fabrication. Finally, the study emphasizes the significance of consistent scan vector provisioning for identical components placed at different build platform positions, assuming no roll or pitch during nesting.
T2 - ICALEO
CY - Orlando, FL, USA
DA - 13.10.2025
KW - Quality assurance
KW - Data management
KW - 3D printing
KW - Laser fabrication
KW - Life cycle analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642104
DO - https://doi.org/10.2351/7.0001890
SN - 1042-346X
VL - 37
IS - 4
SP - 1
EP - 14
PB - American Institute of Physics Publishing
CY - New York
AN - OPUS4-64210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - A decarbonized future requires pipelines for CO2? A brief overview on perspectives and challenges
N2 - Despite the use of hydrogen, for example, in various industrial production processes, CO2 emissions are still unavoidable in the medium term. For example, cement, lime and glass production or waste recycling (waste-to-energy plants) will continue to emit CO2 due to the processing involved chemical reactions. Conversely, the chemical industry with its value chains needs CO2 / carbon as a primary raw material for all compounds that fall within the organic chemistry. In this connection, carbon capture utilization (CCU) will play a key role here. In addition to “natural” methods (via reforestation and the dilution of moors), carbon capture storage (CSS) is already playing a major role, for example by injecting it into old natural gas underground caverns. The resulting quantities of CO2 have to be transported on a large scale and similar to hydrogen pipelines, there are concrete plans for CO2 pipeline networks. For this reason, this presentation provides an introduction to the topic and briefly outlines the associated challenges. On the one hand, these lie in the qualification (testing and construction) and especially in the operation of the pipelines with regard to strict monitoring of the gas quality (e.g. carbonic acid corrosion) and in the avoidance of critical service conditions (sudden pressure fluctuations), which can lead to localized condensation. Among other things, this can lead to the lowering of the typically welded low-alloyed steel pipes below the ductile brittle transition temperature (DBTT) and thus can have an impact on pipeline integrity.
T2 - 49th MPA Conference
CY - Stuttgart, Germany
DA - 06.10.2025
KW - CO2
KW - Pipeline
KW - Welding
KW - Testing
PY - 2025
AN - OPUS4-64316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Component test for simulation of in-service welding on hydrogen pipelines
N2 - Hydrogen is set as the energy carrier of tomorrow and most countries will achieve large-scale hydrogen transport through the conversion of the natural gas (NG) grid and the construction of new pipelines. The interaction between hydrogen and the pipeline materials differs fundamentally from that of NG, as hydrogen is readily absorbed into the material. Considering the possible hydrogen embrittlement (HE), the compatibility of the pipeline materials (low-alloyed steels with a wide strength/thickness range) must be investigated. However, pipelines require intervention for maintenance, repair, or grid expansion with welding on/onto the pipelines while in service, i.e. the well-known "hot tapping" and "stoppling". The challenges compared to NG can be broadly divided into the possible austenitization of the inner pipe material exposed to hydrogen and the welding itself. Both result in a significant increase in hydrogen solubility and could potentially pose challenges in terms of HE. Emphasis is placed on the word "could" because knowledge of "hot tapping" on hydrogen pipelines is scarce due a lack of service experience. To this end, this study proposes a concept for a component-like demonstrator with the objectives: (1) safe feasibility of "hot tapping" on pressurized model hydrogen pipeline sections, (2) facilitate ex-post sample extraction for the purpose of quantifying the absorbed hydrogen concentrations, and (3) ensure in-situ temperature measurement during welding to monitor the pipeline surface temperature. For safety reasons in the event of an unintentional "burn-through", a solid cylinder was inserted in the demonstrator to restrict the hydrogen gas volume to a small, pressurized layer. Reference pipeline surface temperature measurements were ensured on comparable, unpressurized geometries. The investigated range of welding conditions was investigated for representative material/thickness combinations (DN60 to DN300), suggesting the feasibility of the demonstrator for the determination of reliable in-service welding conditions for both installed and new pipelines for hydrogen service.
T2 - 49th MPA Conference
CY - Stuttgart, Germany
DA - 06.10.2025
KW - Hydrogen
KW - Pipeline
KW - In-service welding
KW - Component test
PY - 2025
AN - OPUS4-64317
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - On Shared Vocabulary, Ontologies, Semantic Data and Prototype Applications
N2 - The advancement of development and digitalization in materials science necessitates rigorous quality assurance, interoperability, and adherence to FAIR principles. Semantic technologies contribute to these objectives by facilitating the structured storage, processing, and contextualization of data, yielding machine-actionable and human-interpretable knowledge representations vital for modern data management.
This presentation showcases the prototypical application of generic approaches of knowledge representation in materials science. It includes the design and documentation of graph patterns that may be compiled into rule-based semantic shapes. The development and application of the PMD Core Ontology 3.0 (PMDco 3.0) tailored for materials science is highlighted. Its integration into daily lab life is demonstrated through its functional incorporation into electronic lab notebooks (ELN). In this respect, a possible integration of semantic technologies into openBIS is presented. The openBIS system is usable as a central data storage system that may be complimented by semantic annotation of data to enhance data contextualization and automation. Graph-based knowledge representations and rule-based semantic shapes are shown which were developed alongside the PMD Core Ontology 3.0 (PMDco 3.0) and can enrich openBIS functionalities. Practical examples from material processing and mechanical testing illustrate how semantic extensions of openBIS enable machine-actionable, interoperable, and reusable research data, paving the way for a unified, ontology-driven laboratory data ecosystem.
T2 - openBIS User Group Meeting (openBIS UGM)
CY - Berlin, Germany
DA - 22.09.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - OpenBIS
KW - Ontologies
KW - Graph Patterns
PY - 2025
AN - OPUS4-64307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Ti and Nb influence on the HAZ microstructures of weld-simulated high-strength structural steel S690QL
N2 - High-strength low-alloyed (HSLA) steels with yield strength / proof stress ≥ 600 MPa are the basis of modern light-weight steel constructions. Indeed, the economic and ecological benefits strongly depend on their processability in terms of welding. In this context, the use of highly productive welding processes, suitable welding consumables is of vital interest and requires a fundamental understanding of the microstructural changes in the HSLA steel and especially the heat-affected zone (HAZ) of the welded joint. Microalloying elements, such as Ti or Nb, are essential to achieve the desired mechanical properties. In this context, the underlying standards (such as EN 10025-6) only specify maximum values, resulting in different manufacturer customized microalloy concepts. Furthermore, even small deviations can have a drastic effect expressed by an excessive hardening or softening despite identical welding conditions and filler metal. The reason is the different thermal stability of the Ti and Nb-related precipitates (typically carbides or carbon nitrides). As a result, it is difficult (or even impossible) to adequately predict the weldability. Against this background, different microalloying routes with varying Ti and Nb contents for a S690QL reference grade were systematically investigated in terms of lab-cast alloys close to realistic chemical compositions. To investigate the influence of the welding heat input on the HAZ microstructure formation, physical simulations were carried with specified peak temperatures and cooling times (by a dilatometry). The focus was the identification of the occurring phase transformations during cooling and the final HAZ microstructure. In this context, a double welding cycle was simulated to further identify the behavior of the so-called intercritical HAZ (where softening is likely to occur) in case of the common multi-layer welding for thick plates. The results showed: (1) microalloying has significant influence on the formation of the individual HAZ dependent on (2) the thermal stability of the Ti or Nb-precipitates and (3) synergistic effects of further elements such as Mo and their effect on phase transformations in the HAZ. The results represent a microstructure-based validation of welding processing of such HSLA-steels e.g. in terms of preferred microalloy and weld heat input combinations.
T2 - 49th MPA Conference
CY - Stuttgart, Germany
DA - 06.10.2025
KW - High-strength steel
KW - Microalloy elements
KW - Welding
KW - Weld simulation
KW - Microstructure
PY - 2025
AN - OPUS4-64319
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
T1 - Redesign, Repair, Recycle: R-Strategien bei der additiven Fertigung
N2 - Der Vortrag stellt ausgewählte Beispiele aus Projekten des Kompetenzzentrums AM@BAM vor, die das Potenzial der additiven Fertigung bei der Umsetzung von R-Strategien im Kontext der Kreislaufwirtschaft aufzeigen. PBF-LB/M kann genutzt werden für ein Redesign von Komponenten mit dem Ziel der Gewicht- und Materialeinsparung. Das gleiche Verfahren wie auch DED-ARC und das Kaltgasspritzen können für die Reparatur anspruchsvoller Legierungen oder Geometrien genutzt werden. Das Thema Recycling wird am Beispiel der Wiedernutzung von Pulver aus dem PBF-LB/M-Prozess adressiert.
T2 - DVM-Tagung: Strukturfestigkeit und Produktlebenszyklus – Vom Design bis zur Kreislaufwirtschaft
CY - Berlin, Germany
DA - 07.10.2025
KW - Additive Fertigung
KW - R-Strategien
KW - Repair
KW - Reparatur
PY - 2025
AN - OPUS4-64324
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Uhlig, Marvin
T1 - Schweißverfahrensqualifikation an Stumpfnahtverbindungen aus Altstahl- und Feinkornbaustahl
N2 - Der Erhalt und die Ertüchtigung bestehender Stahltragwerke gewinnen im Bauwesen zunehmend an Bedeutung. Besonders betroffen sind Konstruktionen aus sogenannten Flussstählen, die im Zeitraum zwischen etwa 1880 und 1940, noch vor Einführung der ersten Stahlnorm DIN 488-1, in großem Umfang im Brücken-, Wasserbau- und Hochspannungsanlagenbau verwendet wurden. Diese Stähle wurden in historischen Herstellungsverfahren wie dem Thomas-, Bessemer- oder Siemens-Martin-Verfahren erzeugt und weisen im Vergleich zu heutigen Baustählen eine deutlich größere Streuung in ihren chemischen und mechanischen Eigenschaften auf. Trotz ihres hohen Alters sind viele dieser Tragwerke nach wie vor im Betrieb und befinden sich am Rande ihrer statischen und funktionalen Anforderungen. Ihr Rückbau und Ersatz durch Neubauten sind jedoch oftmals mit erheblichem wirtschaftlichem, logistischem und ökologischem Aufwand verbunden. Daher rückt die Instandhaltung und Weiterverwendung solcher Altbauwerke verstärkt in den Fokus von Infrastrukturprogrammen, Sanierungsstrategien und besitzt eine große kulturelle Bedeutung Im Rahmen der vorliegenden Untersuchung soll das Potenzial des MAG-Schweißens mit G 18 8 Mn Zusatzwerkstoff für Stumpfnahtverbindungen aus Flussstahl und Feinkornbaustahl qualifiziert werden. Ziel ist es, durch experimentelle und werkstofftechnische Analysen weitere Erkenntnisse über die Schweißbarkeit historischer Stähle zu gewinnen, Anwendungsempfehlungen für die Praxis abzuleiten und damit einen Beitrag zur sicheren und wirtschaftlichen Sanierung historischer Infrastrukturbauwerke zu leisten.
T2 - DVS Congress 2025
CY - Essen, Germany
DA - 16.09.2025
KW - Altstahl
KW - MAG-Schweißen
KW - Seigerungen
KW - Instandsetzung
KW - Feinkornbaustahl
PY - 2025
AN - OPUS4-64279
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Uhlig, Marvin
A1 - Schröder, Nina
A1 - Höfer, Kevin
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
A1 - Hensel, Jonas
T1 - Schweißverfahrensqualifikation an Stumpfnahtverbindungen aus Altstahl- und Feinkornbaustahl
N2 - Der Erhalt und die Ertüchtigung bestehender Stahltragwerke gewinnen im Bauwesen zunehmend an Bedeutung. Besonders betroffen sind Konstruktionen aus sogenannten Flussstählen, die im Zeitraum zwischen etwa 1880 und 1940, noch vor Einführung der ersten Stahlnorm DIN 488-1, in großem Umfang im Brücken-, Wasserbau- und Hochspannungsanlagenbau verwendet wurden. Diese Stähle wurden in historischen erstellungsverfahren wie dem Thomas-, Bessemer- oder Siemens-Martin-Verfahren erzeugt und weisen im Vergleich zu heutigen Baustählen eine deutlich größere Streuung in ihren chemischen und mechanischen Eigenschaften auf. Trotz ihres hohen Alters sind viele dieser Tragwerke nach wie vor im Betrieb und befinden sich am Rande ihrer statischen und funktionalen Anforderungen. Ihr Rückbau und Ersatz durch Neubauten sind jedoch oftmals mit erheblichem wirtschaftlichem, logistischem und ökologischem Aufwand verbunden. Daher rückt die Instandhaltung und Weiterverwendung solcher Altbauwerke verstärkt in den Fokus von Infrastrukturprogrammen, Sanierungsstrategien und besitzt eine große kulturelle Bedeutung.
Im Rahmen der vorliegenden Untersuchung soll das Potenzial des MAG-Schweißens mit G 18 8 Mn Zusatzwerkstoff für Stumpfnahtverbindungen aus Flussstahl und Feinkornbaustahl qualifiziert werden. Ziel ist es, durch experimentelle und werkstofftechnische Analysen weitere Erkenntnisse über die Schweißbarkeit historischer Stähle zu gewinnen, Anwendungsempfehlungen für die Praxis abzuleiten und damit einen Beitrag zur sicheren und wirtschaftlichen Sanierung historischer Infrastrukturbauwerke zu leisten.
T2 - DVS Congress 2025
CY - Essen, Germany
DA - 16.09.2025
KW - Altstahl
KW - MAG-Schweißen
KW - Seigerungen
KW - Instandsetzung
KW - Feinkornbaustahl
PY - 2025
SN - 978-3-96144-298-0
VL - 401
SP - 1
EP - 17
AN - OPUS4-64278
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poelke, B.
A1 - Klein, Luise
A1 - Hoffmann, H.
A1 - Wilke, Olaf
A1 - Roloff, A.
T1 - Bestimmung von VOC-Emissionen aus Verbraucherprodukten in mikroskaligen Emissionsprüfkammern: Ergebnisse eines Rundversuchs
T1 - Determining VOC Emissions from Consumer Products in Micro-Scale Emission Test Chambers: Results of a Round Robin Test
N2 - Die Bestimmung der Anfangskonzentrationen flüchtiger organischer Verbindungen, die innerhalb der ersten Stunden des Gebrauchs aus Verbraucherprodukten emittiert werden, wurde in einem Ringversuch getestet, bei dem Mikro-Kammern verwendet wurden. Neun Labore nahmen an dem Ringversuch teil, der sich aus zwei Teilen zusammensetzte: Im ersten Teil wurde die analytische Leistungsfähigkeit beurteilt. Jedes beteiligte Labor erhielt zwei mit Analyten dotierte Tenax® TA Desorptionsröhrchen zur Qualitätskontrolle (QC). Im zweiten Teil führte jedes Labor Emissionsmessungen über einen Zeitraum von 48 Stunden in Mikro-Kammern mit Volumina von 44 oder 114 ml durch. Als Probenmaterial dienten Stücke eines Regenponchos, der Cyclohexanon, Phenol, 2-Ethylhexanol, Naphthalin und Isophoron in signifikanten Konzentrationen emittierte. Für den QC-Test wurden sehr geringe relative Standardabweichungen (9 14 %) erhalten. Die Ergebnisse der Emissionsmessungen waren ebenfalls sehr gut. In der frühen Phase (0,5 4 Stunden) wurden akzeptable z-Scores (|z| ≤ 2,00) von mindestens sieben Laboren erhalten, nach 24 und 48 Stunden erhielten alle Labore akzeptable z-Scores.
KW - Emissionsprüfkammer
KW - Ringversuch
KW - Verbraucherprodukt
KW - VOC-Emission
PY - 2025
DO - https://doi.org/10.37544/0949-8036-2025-03-04-71
VL - 85
IS - 03-04
SP - 71
EP - 76
AN - OPUS4-63561
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pisonero, J.
A1 - Traub, Heike
A1 - Cappella, Brunero
A1 - Álvarez-Llamas, C.
A1 - Méndez, A.
A1 - Richter, Silke
A1 - Ruiz Encinar, J.
A1 - Costa-Fernandez, J. M.
A1 - Bordel, N.
T1 - Exploring quantitative cellular biomaging and assessment of CdSe/ZnS quantum dots cellular uptake in single cells, using ns-LA-ICP-SFMS
N2 - High spatially resolved quantitative bioimaging of CdSe/ZnS Quantum Dots uptake in two kinds of cells is investigated combining laser ablation inductively coupled plasma mass spectrometry and the spatially resolved analysis of dried pL-droplets from a solution with a known concentration of Quantum Dots. Single cells and dried pL-droplets are morphologically characterized by Atomic Force Microscopy. A number concentration of CdSe/ZnS QDs between 3.5 104 and 48 104 is estimated to be uptaken by several selected single cells, after being incubated in the presence of a QDs suspension added to a standard cell culture medium. Mono-elemental bioimaging at subcellular resolution seems to show a higher number concentration of the CdSe/ZnS QDs in the cytosol around the cell nucleus.
KW - LA-ICP-SFMS
KW - Fast single pulse response
KW - Quantitative bioimaging
KW - Cellular uptake
KW - HT22
KW - HeLa
KW - Single cell
KW - pL-droplets
KW - CdSe/ZnS quantum Dots
KW - AFM
PY - 2021
DO - https://doi.org/10.1016/j.talanta.2021.122162
SN - 0039-9140
VL - 227
SP - 122162
PB - Elsevier B.V.
AN - OPUS4-52121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Agudo Jácome, Leonardo
T1 - Navigating the Nanoworld: Understanding Materials Properties with the Transmission Electron Microscope
N2 - The field of materials science is defined as “the study of the properties of solid materials and how those properties are determined by a material’s composition and structure.”. Many –if not most– of the materials that are produced nowadays owe their properties to structures engineered down to the nanoscopic level. This need has been partly realized thanks to the understanding of materials’ building blocks via characterization techniques that reach this level of resolution. Transmission electron microscopy, since its first implementation in the early 1930s (in Berlin), has been implemented to achieve imaging –and spectral– analysis at lateral resolutions down to the atomic level.
In this contribution, a series of practical examples will be presented, where applied materials are characterized by a range of transmission electron microscopy techniques to understand structural and functional properties of a wide range of materials. Among these materials examples will be presented on structural conventionally and additively manufactured metallic alloys, high entropy alloys, dissimilar aluminum-to-steel welds, magnetic nanoparticles, ceramic coatings, high temperature oxidation products. Addressed will be either the effect of processing route or that of the exposure to experimental conditions similar to those found in the respective intended applications.
T2 - UA/UAB/UAH MSE Graduate Seminar
CY - Online meeting
DA - 19.01.2022
KW - Transmission electron microscopy (TEM)
KW - Characterization
KW - Microstructure
KW - 3D
PY - 2022
AN - OPUS4-54238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gadelmeier, C.
T1 - Strengthening mechanisms of single crystalline CrCoNi and CrMnFeCoNi at creep temperatures above 700 °C
N2 - The main deference between high entropy alloys and conventional alloys is the solid solution strengthening effect, which moves from a single element to a multi-element matrix. Little is known about the effectiveness of this effect at high temperatures. Investigation of temperature dependent solid solution strengthening in single phase multicomponent alloys with medium and high entropy using creep testing was performed. Creep tests carried out on single phase SX CrCoNi , CrMnFeCoNi and pure Ni from 700 to 1200 °C excluding oxidation, grain boundaries and multiphase effects. It was found that the influence of solid solution strengthening of CrCoNi and CrMnFeCoNi increases by decreasing temperature (1200 to 700 °C), and dislocation forests occur in CrCoNi and CrMnFeCoNi in comparison to pure Ni.
T2 - SPP Kick-Off Meeting 2nd Phase
CY - Online meeting
DA - 14.04.2021
KW - High entropy alloys
KW - Mechanical properties
KW - Transmission electron microscopy
KW - Solid solution strengthening
PY - 2021
AN - OPUS4-54381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Croteau, Jean-Francois
T1 - Electro-hydraulic forming of SRF cavities: Effect of strain rate on niobium single crystals
N2 - An investigation of the dislocation substructure and mechanical properties of high-purity niobium single crystals with different initial crystal orientations deformed in tension at strain rates of 10^{-4} to 10^3 s^{-1} is presented. Specimens were cut from a large grain niobium disk used for the manufacturing of SRF cavities. Different crystallographic tensile directions exhibited significantly different softening and hardening behaviors and elongation at fracture. Such anisotropy is reduced at high strain rates. Also, different dislocation substructures were observed with TEM at low and high strain rates. At low strain rates, dislocation cells with a high density of long dislocations were observed. At high strain rates, homogeneously distributed dislocations with a higher dislocation dipole density were observed. The relationship between the differences in dislocation substructures and mechanical properties at low and high strain rates and the potential effects on the superconducting properties are discussed.
T2 - 2021 International Conference on RF Superconductivity (SRF'21)
CY - Online meeting
DA - 28.06.2021
KW - Dislocation substructure
KW - Strain rate dependence
KW - Transmission electron microscopy (TEM)
PY - 2021
UR - https://indico.frib.msu.edu/event/38/attachments/158/1089/TUPCAV012_poster.pdf
AN - OPUS4-54540
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Über das Zusammenspiel von Gitterfehlpassung, Kriecheigenschaften und γ'-Würfelform in Hf-W-modifizierten Al10Co25Cr8Fe15Ni36Ti6—Legierungen
N2 - Spurenelemente spielen eine wichtige Rolle bei der Verfeinerung der Eigenschaften von komplexen Materialien. Diese Arbeit zeigt die Korrelation zwischen der Mikrostruktur, der Gitterfehlpassung und den Kriecheigenschaften. Die Legierung Al10Co25Cr8Fe15Ni36Ti6 (in at. %) mit komplexer Zusammensetzung wurde mit den Elementen Hf und W verstärkt. Die Zugabe von Hf bewirkt eine eckigere Form der würfelförmigen gamma'-Ausscheidungen und einen erhöhten Anteil der Heusler-Phase. Die Zugabe von W wiederum formt die Würfelchen rundlicher und löst die Heusler-Phase auf. Eine Mischung der beiden Spurenelemente zeigt einen Übergang zwischen den beiden Extremen, sowohl in Hinsicht auf die Form der Ausscheidungen als auch in Bezug auf die Gitterfehlpassung und die Kriecheigenschaften.
T2 - 11. Metals and Alloys Seminar
CY - Cala Santanyi, Spain
DA - 20.06.2022
KW - Hochentropie-Legierung
KW - Kriechversuche
KW - Gitterfehlpassung
KW - Transmissionselektronenmikroskopie
PY - 2022
AN - OPUS4-55396
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Early Material Damage in Equimolar CrMnFeCoNi in Mixed Oxidizing/Sulfiding Hot Gas Atmosphere
N2 - The use of more and more varied fuels implies an increased list of criteria that need to be addressed when choosing a material for a combustion chamber and its supply pipes. The materials must be very resistant against corrosion, especially when the process takes place at temperatures above 500°C. In this work the influence of SO2 on the surface of the “Cantor alloy” is investigated.
T2 - HEA-Symposium "Potential for industrial applications"
CY - Dresden, Germany
DA - 12.05.2022
KW - High entropy alloy
KW - Corrosion
KW - Sulfiding
KW - Transmission electron microscopy
PY - 2022
AN - OPUS4-55397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodrigues, A. C. P.
A1 - Feller, A.
A1 - Agudo Jácome, Leonardo
A1 - Azevedo, C. R. F.
T1 - Use of synthetic Fe3O4-rich tribofilms to investigate the effect of microconstituents, temperature and atmosphere on the friction coefficient during pin-on-disc tribotest
N2 - This work investigates the effect of the tribotesting parameters (temperature, atmosphere, and third body chemical composition) on the coefficient of friction (CoF) during pin-on-disc dry (PoD) sliding tribotests using artificial third bodies. The third body comprised nanometric Fe3O4-based binary to quaternary chemical compositions containing copper, graphite, and zirconia. These mixtures were manually or ball-milled prepared, and pin-on-disc tribotests were conducted at 23 °C and 400 °C under air or nitrogen atmospheres. Combining PoD and artificial third body to create synthetic tribofilms might be useful for testing new formulations of Cu-free friction materials. Microstructural characterisation of the tribofilms was used to study the stability of the Fe3O4, copper, and graphite nanoparticles under different testing conditions to understand their effects on the CoF. For the Fe3O4-C-ZrO2-X systems, the ball milling mixing promoted the formation of turbostratic graphite in the tribofilm, impairing the lubricating effect of the graphite under air atmosphere at 23 °C. The formation of monoclinic CuO in the tribofilms during tribotests at 400 °C under air and N2 atmospheres promoted a lubricating effect.
KW - Tribology
KW - Microstructure
KW - Oxide
KW - Transmission electron microscopy
PY - 2022
DO - https://doi.org/10.1088/2051-672X/ac9d51
SN - 2051-672X
VL - 10
IS - 4
SP - 044009-1
EP - 044009-18
PB - IOP Pobilishing
AN - OPUS4-56467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Mechanical performance and integrity of tungsten inert gas (TIG) welded CoCrFeMnNi high entropy alloy with austenitic steel AISI 304
N2 - High entropy alloys (HEA) are a new class of materials that have been investigated since the early 2000s and offer great potential to replace conventional alloys. However, since they sometimes have significant contents of expensive alloying elements such as Co or Ni, their use is only conceivable in highly stressed areas of components. For this purpose, the weldability with conventional alloys such as high-alloy austenitic steels must be investigated. In addition to the resulting microstructure, the mechanical properties are also fundamental for the usability of HEAs in DMWs. For this purpose, TIG welds of CoCrFeMnNi HEA (cold rolled and recrystallized state) with AISI 304 austenitic steel are investigated. These mechanical properties are analyzed in this work by means of tensile tests and local hardness measurement. The local strain behavior of the welded joints is also characterized by means of Digital Image Correlation (DIC). The results of the local hardness measurement show a clear influence of the initial condition of the HEA on the HAZ. Thus, the HEA in the cold-rolled condition shows a clear softening because of recrystallization processes in the HAZ. On the other hand, there is no influence on the hardness of the weld metal, which is approx. 200 HV0.1 in both cases. The tensile tests show a consistent failure of the weld in the weld metal. However, regardless of the HEA condition, strengths in the range of the recrystallized HEA (RM ~ 550–600 MPa) are achieved, although with significantly reduced fracture elongations.
T2 - International Conference on High-Entropy Materials (ICHEM 2023)
CY - Knoxville, TN, USA
DA - 18.06.2023
KW - Multi-principal element alloys
KW - Welding
KW - Mechanical properties
KW - Dissimilar metal weld
KW - Digital image correlation
PY - 2023
AN - OPUS4-57713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Damage induced by electric field of gold microparticles on silicon oxide substrate in the scanning electron microscope
N2 - 1. Introduction
A normally unwanted process that can arise when converging an electron beam onto, e.g. microparticles, has been called "damage induced by electric field" (DIEF) [1]. By DIEF, the convergent electron beam (CEB) imparts a high amount of energy to the microparticle locally and strongly interacts with its atoms. At a specific current density J, which can be controlled by the convergence angle α, the irradiated material begins to transform. The phenomenon of expelling nanomaterial from microparticles under the influence of a convergent electron beam (CB) in a transmission electron microscope (TEM) has been largely studied [2]. Several types of nanoparticles (NPs) have been observed for different metallic materials and metal oxides after specific CB protocols (P) in the TEM. Thus, DIEF can be used as a promising synthesis method controlled changes of micrometric material to create new nanometric material compositions and morphologies.
While these reactions have been observed in situ at the high acceleration voltages associated with TEM, it remains unclear whether the SEM can also be used to fabricate NPs via DIEF. In contrast to TEM there is no possibility to statically convert the electron beam to a range of α to reach the needed J as in TEM. Instead, the scanning parameters and the magnification can be manipulated so as to find an integrated J. Considering that the scanning electron microscope (SEM) is easier to use, more accessible and cheaper than a TEM, here we explore the possibility to transfer the concepts of DIEF known to operate in the TEM for in situ NP generation SEM.
2. Objectives
The main goal is to determine whether DIEF can be translated to the SEM perform to controlled in situ fabrication of nanoparticles from microparticles, using gold microparticles on amorphous SiO substrate as precursors. We determine what experimental parameters must be taken into account to create SEM-based CBPs for NP creation in the SEM with these materials.
3. Materials & methods
Gold microparticles with diameter of around 1 to 3 µm were deposited on electron transparent amorphous SiO/SiO2 substrate. Using a convergent electron beam protocol (CBP) in a scanning electron microscope (SEM) at an acceleration voltage of 30 kV, the gold microparticles were irradiated until a production of NPs takes place as shown in figure 1. The beam current varied between 16 and 23 nA.
4. Results
Depending on the CBP parameters, either only Au NPs or a mixture of Au and Si NPs are produced. The particle size ranges from a few nm up to 100 nm, and it depends on the distance of the NP to the initial position of the microparticle. Further beam parameters such as the dwell time, the effective irradiated volume and particle size determine whether NPs are produced or if the microparticles only are expelled from the substrate without reacting.
5. Conclusion
The SEM can be used as an instrument for synthesizing nanomaterials via DIEF. Different CBP protocols can be applied for obtaining either gold nanoparticles or silicon + gold nanoparticles
T2 - Microscopy Conference
CY - Darmstadt, Germany
DA - 26.02.2023
KW - Scanning electron microscopy (SEM)
KW - Gold nanoparticles
KW - Electron beam induced modification
PY - 2023
AN - OPUS4-58261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Complex artificial features on a TEM transparent membrane
N2 - The phenomenon of expelling nanomaterial from microparticles of different materials, such as Au, WO3 or B2O3 under the influence of a convergent electron beam (CB) of a transmission electron microscope (TEM) was reviewed by Ignacio Gonzalez-Martinez [1]. Converging the e-beam in a TEM means that a high amount of energy enters the microparticle at a very local place and interact with the matter. Obviously, during the convergent beam protocol, no imaging with the electron beam is possible, but at the end, nanoparticles with different appearances lie down next to the microparticle while its size is reduced.
Hence, there is a blind spot in the observation, which we want to fill, as we want to help clarify the nature of the expelling phenomenon. One hypothesis that explains the phenomenon is the so-called damage (of the microparticle) induced by an electric field (DIEF). Within this theory, the material is ionized and expelled in form of ionic waves. Our aim is therefore to fabricate specimens with artificial microlandscapes, as schematically exemplified in figure 1a), using the focused ion beam (FIB) and micromanipulators, as experimental setups to follow the paths of the expelled material.
As a first step towards the fabrication of such specimen, we make experimental feasibility studies for each fabrication method, FIB structuring with Ga+ ion beam and micromanipulated microparticle deposition. Bridges (gray regions in Fig. 1) are created by milling a commercially available electron transparent membrane (silicon oxide or carbon) of a Cu-TEM grid. Platinum or carbon walls (blue features in Fig. 1) are built to stand on those bridges. Microparticles (yellow sphere in Fig. 1) of gold or other material are deposited in the center of the bridges.
Figure 2a) shows four square holes (black area) and between them the residual silicon oxide membrane bridges (dark grey). On top of the bridges, walls (light grey) are deposited. The width of the bridges is different, the walls overlap the holes as well as the distance between the walls is very small, so these and other parameters need to be optimized. Figure 2b) shows a square hole (black) with bridges (white) on the right side on top of a carbon membrane (grey). There are still some obstacles which needs to be eliminated. For instance, the deposition process of the walls is not reliable as visible at the wall on top where a hole arises instead of a wall.
These studies are still in progress and the results are further discussed in terms of the applicability for the DIEF experiment in the TEM.
T2 - 4th EuFN and FIT4NANO Joint Workshop / Meeting
CY - Vienna, Austria
DA - 27.09.2021
KW - Transmission electron microscope (TEM)
KW - Sample preparation
KW - Micromanipulation
KW - Focussed ion beam growth
KW - Nano-landscape
PY - 2021
AN - OPUS4-58259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Welding of high-entropy alloys - New material concept vs. old challenges
N2 - HEAs represent a relatively new class of materials. The the alloy concept is fundamentally different from the most conventional materials and alloys that are used today. Recently, the focus of HEA designs is more application-based. For that purpose, the elements of interest are carefully selected and multiple phases as well as micro-structures are deliberately adjusted. Currently, only limited attention has been paid to weldability of HEA. This encompasses possible effects on metallurgy and its influence on the desired properties. It remains open if welding causes e.g. considerable number of intermetallic phases or segregations and their effect on weld joint properties. For that reason, the scope of this study is to summarize already available studies on welding of HEAs with respect to the HEA-type, the applied welding process and its influence on the weld joint properties.
T2 - IIW Annual Assembly, Meeting of Commission II-A
CY - Online meeting
DA - 20.07.2020
KW - High-entropy alloy
KW - Welding
KW - Review
PY - 2020
AN - OPUS4-51116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Orazio Lepore, G.
A1 - Manzoni, Anna Maria
A1 - Kasatikov, S.
A1 - Scherb, T.
A1 - Huthwelker, T.
A1 - d'Acapito, F.
A1 - Schumacher, G.
T1 - Short-range chemical order and local lattice distortion in a compositionally complex alloy
N2 - This work presents an X-ray absorption spectroscopy study on a single-phase state of the Al8Cr17Co17Cu8Fe17Ni33 compositionally complex alloy, focused on the local crystal structure around each alloying element. The comparison of 1st shell bond lengths, obtained by the analysis of extended X-ray absorption fine structure (EXAFS) measured at the K-edges of each alloying element, indicates that Al8Cr17Co17Cu8Fe17Ni33 crystallizes in a distorted arrangement of an fcc lattice. A modest bond length dependence of the alloying elements with increasing atomic number is observed, with minima and maxima at Cr/Co, and Al/Cu, respectively. 1st shell bond lengths spread over ~0.03 Å; consequently, such variations cannot result in lattice distortions greater than ~0.04 Å. EXAFS results clearly indicate short-range order in the alloy: pairing of Al with Ni and Cu is favored, correlating well with a g’ precipitate composition (Al-Ni-Cu rich) reported in previous work, while Al-Cr bonding is unfavored and no Al-Al pairs are observed. Electronic structure information was obtained through comparison between near-edge regions of alloying Elements and corresponding pure metals. Intensity comparison of K-edge features agree with a charge variation of p states in Al8Cr17Co17Cu8Fe17Ni33, where Ni and Cu act as p states electron acceptors, suggesting an orbital hybridization with Al, responsible for a shrinkage in Al metallic radius in the alloy by 0.17 Å.
KW - High entropy alloys
KW - EXAFS
KW - Compositionally complex alloys
PY - 2020
DO - https://doi.org/10.1016/j.actamat.2020.04.034
VL - 193
SP - 329
EP - 337
PB - Elsevier Ltd.
AN - OPUS4-50830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Manzoni, Anna Maria
A1 - Glatzel, U.
ED - Buschow, K.H.J.
ED - Flemings, M.C.
ED - Kramer, E.J.
ED - Veyssière, P.
ED - Cahn, R.W.
ED - Ilschner, B.
ED - Mahajan, S.
T1 - High-Entropy Alloys: Balancing Strength and Ductility at Room Temperature
N2 - A new race for high performance structural materials has started since the discovery of high entropy alloys at the beginning of the 21st century. The possible combination of several elements in an, until then, unknown composition space opened the ground for discovering new materials. Solid solution strengthening remains the most prominent mechanisms that is active in this family of materials, but it is supported by all other strengthening mechanism on the path to better and better performing materials. Chemical, thermal and mechanical approaches are combined to optimize these alloys. Optimum performances can be reached by using a high number of different strengthening mechanisms, induced both by composition and processing. The most prominent with composition induced mechanism is precipitation hardening, and on the processing side it is cold working such as cold-rolling, torsion or extrusion. The contribution uses tensile test data at room temperature solely for comparison – high temperature and cryogenic data are omitted because it would lead beyond the scope of this manuscript.
KW - High entropy alloys
KW - Compositionally complex alloys
PY - 2020
DO - https://doi.org/10.1016/B978-0-12-803581-8.11774-6
PB - Elsevier Inc.
AN - OPUS4-50575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - Microstructural characterization of the AlMo 0.5 NbTa 0.5 ZrTi refractory complex concentrated alloy
N2 - A set of some unexpected and interesting microstructures has put the so-called complex concentrated alloys (CCAs) in the eye of the scientific community and the AlMo0.5NbTa0.5TiZr refractory (r)CCA, aimed at substituting Ni-base superalloys in gas turbine applications, belongs to this alloy family. The AlMo0.5NbTa0.5TiZr rCCA was studied by SEM, EDX, EBSD and TEM, showing the presence of a nanoscopic basket-wave structure inside the grains, with two BCC phases. Additionally, thermodynamic calculations on the AlMo0.5NbTa0.5TiZr alloy were done with two different proprietary databases that anticipate two BCC-disordered phases with distinct constitutions as well as an HCP phase.
T2 - Symposium on Advanced Mechanical and Microstructural Characterization of High-Entropy Alloys
CY - Bochum, Germany
DA - 03.02.2020
KW - High Entropy Alloy
KW - EBSD
KW - Microstructure Characterization
PY - 2020
AN - OPUS4-50729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sonnenburg, Elke
T1 - Präparation, Kontrastierung und Darstellung des Gefüges von additiv gefertigtem austenitischem Stahl 316L
N2 - Der weit verbreitete austenitische Stahl 316L soll auch mittels additiver Fertigung verarbeitet werden (316L-AM). Zur Entwicklung optimaler Aufbauverfahren ist ein detailliertes Verständnis des Gefüges notwendig. Das additiv aufgebaute Gefüge zeigt eine Mikrostruktur, die geprägt ist von sehr hohen Abkühlraten und gerichtetem Kornwachstum. Mittels klassischer Metallographie können die Charakteristika des Gefüges wie Körner, Subkörner und Schmelzlinien sichtbar gemacht werden. Mittels EBSD werden Kristallorientierungen ermittelt und bildhaft aufbereitet. Die Feinstruktur der Körner wird im REM in der Übersicht aufgelöst. Erst im TEM kann bei hoher Vergrößerung die Natur der Zellstruktur quantitativ ermittelt werden.
T2 - Metallographie 2020
CY - Online meeting
DA - 16.09.2020
KW - Präparation
KW - Kontrastierung
KW - Additiv gefertigter Stahl
PY - 2020
AN - OPUS4-51244
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gawlitza, Kornelia
T1 - Using Dual Fluorescent Molecularly Imprinted Particles Coupled with a Miniaturized Opto-Microfluidic Platform for On-Site Detection of Perfluoroalkyl Carboxylic Acids
N2 - Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic organofluorine chemicals widely used in the production of various materials, including firefighting foams, adhesives, and coatings that resist stains and oil. In recent years, PFAS have gained attention as emerging environmental contaminants, with particular emphasis on perfluoroalkyl carboxylic acids (PFCAs), the most common type of PFAS. PFCAs are defined by a fully fluorinated carbon chain and a charged carboxylic acid group. They have been classified as Substances of Very High Concern and included in the REACH Candidate List due to their persistence, resistance to biodegradation, and toxicological impacts.
Traditional methods for analyzing PFCAs, like GC-MS, HRMS, and HPLC-based techniques, are time-consuming, non-portable, expensive, and require specialized expertise. On the other hand, fluorescence assays offer a user-friendly, portable, and cost-effective alternative with high sensitivity and quick results, particularly when the binding of the analyte causes a specific increase in the probe’s fluorescence. Combining these probes with a carrier platform and a miniaturized optofluidic device presents a promising approach for PFCA monitoring.
In this study, a new guanidine BODIPY fluorescent indicator monomer was synthesized, characterized, and incorporated into a molecularly imprinted polymer (MIP) designed for the specific detection of perfluorooctanoic acid (PFOA). The MIP layer was formed on silica core nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, serving as an optical internal reference for calibration-free assays. In combination with an extraction step prior to sample analysis, this system enables selective and reliable detection of PFCAs in surface water samples, minimizing interference from competing substances, matrix effects, and other factors. When integrated into an opto-microfluidic setup, the assay provided a compact, user-friendly detection system capable of detecting micromolar levels of PFOA in under 15 minutes from surface water samples.
T2 - ANAKON2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Perfluorooctanoic Acid (PFOA)
KW - On-site detection
KW - Fluorescence
KW - Microfluidics
KW - Molecularly Imprinted Polymers
PY - 2025
AN - OPUS4-62712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - High temperature oxidation of the CrFeNi medium entropy alloy
N2 - The oxidation behaviour of any alloy is a key issue which determines whether this material is suited for application. In this study, a single-phase equiatomic CrFeNi alloy was exposed to synthetic air at 1000 - 1100 °C for 24 - 1000 h and compared to 316L steel. The oxidation rate of CrFeNi was parabolic at the lower temperatures 1000 °C and 1050 °C, but at 1100 °C a first breakaway occurred after 4 h of exposure. In all cases, the oxide scales were found to partially spall off. As expected, Cr diffuses outwards to form a Cr2O3 layer at the gas/oxide interface. A thin layer of (Cr, Fe, Ni)3O4 is identified at the oxide/alloy interface. The CrFeNi alloy does not show any catastrophic oxidation behaviour at the investigated conditions unlike the 316L alloy, which contains more Mn and Fe.
T2 - MSE 2024
CY - Darmstadt, Germany
DA - 24.08.2024
KW - Corrosion
KW - Medium entropy alloy
KW - Scanning electron microscopy
PY - 2024
AN - OPUS4-62434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - López-Puertollano, Daniel
T1 - Superparamagnetic core-shell particles application: from cytometry assay to simplified fluidic system
N2 - Superparamagnetic hybrid polystyrene-core silica-shell beads have emerged as promising alternatives to traditional in flow cytometry-based competitive antibody assays [1]. These materials consist of a polystyrene core and a silica shell, in which magnetic nanoparticles are embedded, facilitating the handling and retention in tests. The outer silica surface allows for easy modification through silane chemistry, allowing the attachment of antibodies, or other molecules of interest. Ochratoxin A (OTA), a mycotoxin that can be found in grain products, coffee, cacao, or grapes, was chosen as the main target analyte to detect [2]. In this study, previously in house produced anti-OTA antibodies [3] were attached to the surface of the particles and the whole system was used as detection entity. In a first approach, the system was used for the development of a competitive cytometry assay using an OTA-fluorescein (OTA-F) adduct as competitor and marker. In this assay the fluorescence emitted by the OTA-F competitor on the surface of the particle was detected at a wavelength of 518 nm using a 533/30.H filter and was correlated to the forward scatter (FSC) to distinguish it from the excess of competitor still in solution. Under optimised conditions, the final assay showed a limit of detection of 0.03 nM. In a second approach, a simplified ready-to-inject fluidic system was built based on a laser (488 nm) and a photomultiplier detector to measure the signal of competitor still in solution. The competition step was carried out in a vial and the whole mixture was injected into the fluidic system. To avoid signal scattering, the particles were separated in-line using a magnet and only the OTA-F competitor still in solution was detected, reaching a limit of detection of 1.2 nM. With the aim to reduce user manipulation, the final assay is still under development for in-line incubation during the competitive step.
T2 - 15th Rapid Methods Europe Conference
CY - Amsterdam, Netherlands
DA - 06.11.2023
KW - Microfluidics
KW - Flow cytometry
KW - Bead-based assays
KW - Magnetic beads
KW - Core-shell particles
KW - Immunoassays
PY - 2023
AN - OPUS4-58817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Damage induced by electric field of microparticles in the electron microscope
N2 - Damage induced by electric field (DIEF) that happens in the transmission electron microscope (TEM) when converging the electron beam (e-beam) on microparticles (MPs) can be used to synthesis new nanomaterial and nanomaterial compositions. The research questions are to clarify the limits and possibilities of the method regarding materials that can be produced, systems to which it is applicable and working beam parameters. Synthesis of nano-objects from microparticles using DIEF in TEM could be shown for different materials. Additionally, DIEF using the e-beam in a scanning electron microscope (SEM) can also be used to synthesis nano-objects. A deeper material analysis of this nano-objects was done using TEM and shows that the material of the nanoparticles (NPs) can be gold or/and silicon. Furthermore, the size of the NPs depends on the distance to the center of DIEF whereby the larger NPs are closer to the center. The areas of gold NPs are promising candidates for plasmonic or photonic devices for energy storage or transport.
T2 - PhD-Day 2022
CY - Berlin, Germany
DA - 06.09.2022
KW - Electron microscopy
KW - Electron beam induced modification
KW - Gold nanoparticles
PY - 2022
AN - OPUS4-58264
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - A decade of cube optimization in the Al- Co-Cr-Fe-Ni-Ti high entropy family
N2 - The multi-phase approach has proven to widen the application properties of high entropy alloys. After a decade of testing different alloys in the Al-Co-Cr-Cu-Fe-Ni-Ti family the Al10Co25Cr8Fe15Ni36Ti6 was found to be a solid base for more fine-tuned microstructural optimization. Following the example of superalloys, the Al10Co25Cr8Fe15Ni36Ti6 alloy aims for a γ/γ' microstructures in order to guarantee a good microstructural stability at high temperatures. The shape and volume fraction of the γ' particles is known to influence the mechanical properties of superalloys, and they do so in the high entropy family as well [1]. Shape, misfit and creep properties of several modified versions of the Al10Co25Cr8Fe15Ni36Ti6 alloy are compared and discussed in this talk.
T2 - Department seminar National Chung Hsing University
CY - Taichung, Taiwan
DA - 15.11.2023
KW - High entropy alloys
KW - Transmission electron microscopy
KW - X-ray diffraction
KW - Creep
KW - Phase analysis
PY - 2023
AN - OPUS4-58979
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Agudo Jácome, Leonardo
T1 - The Al4-xZr5(Ox-y) Trojan horse in the AlMo0.5NbTiTa0.5Zr refractory high entropy superalloy
N2 - Unlike conventional alloys, which typically consist of one main element, high-entropy alloys (HEAs) contain five or more principal elements, which broaden chemical complexity and with it a realm of synergistic mechanisms. The AlMo0.5NbTa0.5TiZr HEA initiated a subclass of Al-containing refractory (r)HEAs that has recently drawn attention [2]. The alloy has a superalloy-resembling B2/bcc nanostructure, which inspired its name refractory high entropy superalloy (RSA). With high-temperature (HT) compressive strengths beyond conventional Ni-based superalloys, this nanostructure could be used for improved HT structural applications. However, in the application-relevant HT regime the Al-Zr-rich B2 phase decomposes to form a hexagonal Al-Zr-based intermetallic (Al4-xZr5; x: 0..1) [3,4]. This work explores the fascinating yet fatal micromechanisms associated to this phase transformation, in the context of creep, annealing and oxidation experiments performed between 800 and 1200 °C.
The material was produced by arc-melting and heat treatment in argon, which lead to grain boundaries decorated with up to 7%. Interrupted constant-load creep tests were performed under vacuum (at 10-4 Pa), at 900–1100 °C with external tensile stresses of 30–120 MPa. Oxidation experiments were separately conducted for 24 hours at 800 and 1000 °C in both dry (21% O2 + 79% N2) and humid (8% O2 + 74% N2 + 18% H2O) air. After the experiments, the samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy to reveal degradation mechanisms. Crystallographic texture, orientation relationships and stabilization of an oxygen-containing iso structure (Al4-xZr5(Ox-y); y: 0..x) of the Al-Zr-rich intermetallic are found and discussed.
T2 - BCC Superalloy Network Opening Workshop
CY - Reutte, Austria
DA - 08.02.2024
KW - High entropy alloy
KW - Superalloy
KW - Degradation
KW - Electron microscopy
KW - Microstructure
PY - 2024
AN - OPUS4-59833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Corrosion in the Co-Cr-Fe-Ni high entropy alloy family
N2 - While a lage amount of research on high entropy alloys is oriented towards mechanical properties and the microstructural improvement it is also necessary to keep an eye on the environment that potential application materials will be submitted to. The Co-Cr-Fe-Ni based high entropy family has shown great potential over the years of high entropy research and some candidate alloys are chosen for an insight into their corrosion behaviour. Several atmospheres are studied, i.e. O2, H2O, SO2 and a mix thereof in argon as well as synthetic air. Just as for classic alloys, the chromium is the most important element in terms of protection agains further corrosion. The addition of manganese, as in case of the “Cantor alloy” CrMnFeCoNi, overpasses Cr when it comes to oxygen affinity and thus counteracts the layer formation of Cr2O3. Even without Mn, a temperature chosen too high will also affect the formation of the chromium oxide layer and spall it off, annulling its protective potential. We can also observe how trace elements influence the layer formation. These effects and their mechanisms will be discussed for the alloys CrFeNi, CoCrNi, CrMnFeCoNi and variations of Al10Co25Cr8Fe15Ni36Ti6 using a combination of electron microscopy, thermodynamic calculations and x-ray diffraction.
T2 - MRS-T International Conference
CY - Hsinchu, Taiwan
DA - 17.11.2023
KW - Corrosion
KW - Scanning electron microscopy
KW - Mixed gas atmosphere
PY - 2023
AN - OPUS4-58980
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Fabrication of 2D assemblies of disordered gold nanoparticles and investigation of localized surface plasmon resonances
N2 - Interaction of electromagnetic waves, such as electron beams or light, with conductive material can lead to localized surface plasmon resonances (LSPRs) where the incoming energy can be deposited in a collective excitation of electrons of the conduction band, which in turn can result in coherent localized plasmon oscillations. LSPR in metallic nanostructures, such as nanoparticles (NPs), which are sensitive to geometry, material composition and environment, are currently utilized in a wide range of applications, such as surface-enhanced Raman spectroscopy, plasmonic wave guides, improved solar cells, on-chip particle accelerators and nanoantennas. A host of studies that focus on plasmonic NPs ranging from single NPs with several shapes (cubic, spherical, tetrahedral) over 1D assemblies of NPs such as chains, to ordered 2D assemblies of NPs show an increase of the complexity regarding the hybridization behavior of LSPRs eventually lead to delocalized Surface Plasmons. Furthermore, Anderson predicted in 1977 the absence of diffusion or delocalization of waves in disordered systems, which has been discussed as the underlying mechanism for LSPRs localization in disordered metallic thin films and ultrathin 2D networks. Our aim is to further develop these studies on the surface plasmon localization in disordered structures by (1) developing a novel NPs assembly fabrication method that allows fabricating disordered assemblies of NPs of a wide range of NPs sizes, and (2) probing the LSPR with high-resolution electron energy-loss spectroscopy (EELS). Moreover, the dominant dipolar interaction between the NPs, also facilitates an efficient numerical modeling of these systems, which in comparison with the experiments allows for an in-depth study of the impact of various geometric parameters as well as retardation and life-time damping on the observed localization behavior.
To synthesize 2D disordered assemblies of gold NPs on a TEM transparent silicon oxide substrate, a new synthesis routine was developed. This procedure is based on sublimation and redeposition of a gold microparticle precursor induced by an electron beam in a scanning electron microscope (SEM) operated at 30 kV. To characterize the assembly of synthesized NPs in terms of size, shape and spreading over the substrate, TEM measurements were conducted subsequently. To study LSPRs experimentally, EELS in scanning transmission electron microscopy (STEM) mode was carried out. The numerical modelling of LSPRs was performed using a self-consistent dipole model.
The synthesized 2D disordered gold NPs assemblies exhibit a gradient in the NPs mean size, which ranges from 100 nm close to the precursor location down to 2 nm at a distance of more than 20 µm from the precursor location. Additionally, the interparticle distance between the gold NPs increases with increasing distance to the precursor location.
The experimental investigation as well as the numerical simulation of the LSPRs demonstrate a localization behavior that decreases toward larger energies, which is driven by the disorder of the NPs assembly (mainly the random particle distance). That localization behavior stays in contrast to what was found in ultrathin 2D gold networks showing increasing of localization towards higher LSPRs energies. By varying the geometric parameters of the NPs assembly in the simulation, we could identify the NPs thickness as the parameter, that determines the energy-dependence of the localization. Specifically, a critical thickness of approx. 10 nm separates the two localization regimes, which correlates to the energy of the dipole mode resonance crucially depending on the thickness of the NPs.
2D disordered assemblies of gold NPs of a wide range of NPs sizes and distances can be synthesized directly on thin substrates facilitating structural characterization and EELS measurements in a TEM. It could be shown that such assemblies exhibit LSPRs with a localization behavior that may be tuned by the NPs sizes (including thickness) and interparticle distances. The proposed synthesis of random NPs assemblies opens new avenues for fundamental studies on Anderson localization in disordered plasmonic structures as well as its applications such as surface-enhanced Raman spectroscopy where localization behavior must be tuned to specific wave lengths.
T2 - 17th European Microscopy Congress (EMC 2024)
CY - Copenhagen, Denmark
DA - 26.08.2024
KW - Transmission electron microscopy
KW - Scanning electron microscopy
KW - Localized surface plasmon resonances
KW - Gold nanoparticle synthesis
KW - Disordered assemblies
PY - 2024
AN - OPUS4-60947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gawlitza, Kornelia
T1 - On-Site Detection of PFAAs with Dual Fluorescent MIPs Coupled to a Miniaturized Microfluidics Platform
N2 - Per- and polyfluoroalkyl substances (PFAS) represent a class of synthetic organofluorine chemicals extensively utilized in the manufacturing of various materials such as firefighting foams, adhesives, and stain- and oil-resistant coatings. In recent years, PFAS have been considered as emerging environmental contaminants, with particular focus on perfluoroalkyl carboxylic acids (PFCAs), the most prevalent type among PFAS. PFCAs are characterized by a fully fluorinated carbon backbone and a charged carboxylic acid headgroup. Notably, they have been designated as Substances of Very High Concern and added to the REACH Candidate List due to their persistence in the environment, non-biodegradability and toxicological effects.
Conventional techniques for the analysis of PFCA, such as GC-MS, HRMS and HPLC-based methods, are laborious, not portable, costly and require skilled personnel. In contrast, fluorescence assays can be designed as easy-to-operate, portable and cost-effective methods with high sensitivity and fast response, especially when analyte binding leads to a specific increase of a probe’s emission. Integration of such probes with a carrier platform and a miniaturized optofluidic device affords a promising alternative for PFCA monitoring.
Here, a novel guanidine BODIPY fluorescent indicator monomer has been synthesized, characterized, and incorporated into a molecularly imprinted polymer (MIP) for the specific detection of perfluorooctanoic acid (PFOA). The MIP layer was formed on tris(bipyridine)ruthenium(II) chloride doped silica core particles for optical internal reference and calibration-free assays. Such system allows selective and reliable detection of PFCA from surface water samples, with minimum interference by competitors, matrix effects and other factors. Integration of the assay into an opto-microfluidic setup resulted in a miniaturized and easy-to-operate detection system allowing for micromolar detection of PFOA in less than 15 minutes from surface water sample.
T2 - MIP2024: The 12th International Conference on Molecular Imprinting
CY - Verona, Italy
DA - 18.06.2024
KW - Sensor
KW - PFAS
KW - Molecularly imprinted polymers
KW - Guanidine receptor
KW - BODIPY
PY - 2024
AN - OPUS4-60438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Two decades of cuboids in high entropy alloys
N2 - One of the original concepts of high entropy alloys was the use of single-phase alloys that were strengthened by the presence of many different main elements. After some years of research, it was found that this strengthening could be enhanced further by the introduction of a carefully chosen second phase that has a connection to the matrix phase. A most suitable combination is the combination of a ductile matrix phase with a disordered structure and an intermetallic precipitation phase that is coherent to the matrix. The most well-known example is the gamma-gammaprime morphology that is known from Ni-base superalloys, but it is not the only one. Combination of fcc-B2 or bcc-B2 have been discovered and optimized in several alloys and they lead the materials to beautiful microstructures with admirable properties.
This talk presents the different types of cuboid formations in HEAs that have been presented in the last two decades.
T2 - 32nd International Materials Research Congress - IMRC 2024
CY - Cancun, Mexico
DA - 18.08.2024
KW - High entropy alloys
KW - Chemically complex materials
KW - Transmission electron microscopy
PY - 2024
AN - OPUS4-60935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Fluorine Depth Profiling in Lithium-Ion Battery Materials by GD-OES
N2 - Lithium-ion batteries are a key technology for tackling challenges in energy and climate crisis, but up to 30 % are discarded right after production. Quality is closely related to the homogeneity of the used materials and coatings. Fluorine compounds, both in the polymer and from degradation of the electrolyte, are of special interest for the formation and aging of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) emerged as a fast and convenient method for depth-profiling of battery materials. However, fluorine remains a spectroscopic challenge due to a high excitation energy and only few strong emission lines in the UV/Vis spectral range.
We investigated the partial substitution of argon with neon in the plasma gas. The main emission line at 685.603 nm was monitored by both photo multiplier tube (PMT) with Czerny-Turner monochromator at 20 µm slit-size, and charge-coupled device (CCD) with 1200 lines/mm grating. For calibration, we used a set of hot-pressed copper cylinders with varying calcium fluoride amount fraction, ranging from 1.6 % to 4.4 %. Plasma gas mixtures with a mole fraction of 5 %, 10 % and 20 % neon in argon were used. Sensitivity in comparison to pure argon was increased by factor 4, 7 and 14, respectively. In general, PMT detection was more sensitive than CCD. As expected, sputter rates decreased with higher neon content in the plasma gas. Depth-profiling of the cathodes was performed in pulsed mode at constant voltage and pressure, which resulted in stable plasma conditions. We achieve matrix-independent quantitative information on fluorine distribution by correction based on sputter rates.
This advancement in GD-OES provides a more accurate analytical approach for evaluating the homogeneity of lithium-ion battery materials, potentially leading to more sustainable and cost-effective manufacturing processes.
T2 - 6th International Glow Discharge Spectroscopy Symposium
CY - Liverpool, United Kingdom
DA - 21.04.2024
KW - Lithium Ion Batteries
KW - GD-OES
KW - depth-profiling
KW - fluorine
PY - 2024
AN - OPUS4-60200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Prabhakara, Prathik
T1 - Ein synergistischer Ansatz zur Charakterisierung anisotroper Materialien mit Hilfe von Ultraschall und Mikrostrukturanalyse
N2 - Es wird eine Studie zur Charakterisierung eines anisotropen Stahls vorgestellt, bei der Ultraschalluntersuchungen mit Mikrostrukturanalysen verbunden werden. Das Material weist hohe Festigkeit und Korrosionsbeständigkeit auf, zugleich ist mit anisotropen Eigenschaften die mechanischen und betrieblichen Eigenschaften beeinflussen zu rechnen. Vorläufige Ergebnisse lassen vermuten, dass weitere Untersuchungen notwendig sind, um die Fähigkeiten und Grenzen des Materials genau zu bestimmen. Es wird ein systematischer Ansatz mit Array- Prüfköpfen, Time-of-Flight Diffraction (TOFD) Technik und mikrostrukturellen Untersuchungen angewendet, um die Wechselwirkung zwischen Anisotropie und Mikrostruktur des Stahls zu analysieren. Ultraschallprüfungen mit der TOFD-Technik und in Tauchtechnik liefern Einblicke in das anisotrope Verhalten des Werkstoffes, einschließlich entsprechenden Kornorientierung, Dämpfung und Schallgeschwindigkeitsvariation. Diese Messungen führen in Verbindung mit mikrostrukturellen Analysen zu einem tieferen Verständnis des Materialverhaltens. Unser Hauptziel ist es, ein Framework zu erstellen, welches die Ultraschallantwort anisotroper Materialien mit ihren mikroskopischen Struktureigenschaften verbindet. Die vorgestellte Methodik ermöglicht eine zerstörungsfreie und zügige Bewertung der Materialintegrität, was besonders bei der Anwendung von Hochleistungsmaterialien relevant ist. Durch diesen integrativen Ansatz werden verschiedener Charakterisierungsmethoden kombiniert, um ein umfassenderes Materialverständnis zu erreichen.
T2 - DGZfP-Jahrestagung 2024
CY - Osnabrück, Germany
DA - 06.05.2024
KW - Ultrasonic Testing
KW - Material Characterization
KW - Microstructure Analysis
KW - Time-offlight Diffraction (TOFD)
KW - Non-Destructive Testing
PY - 2024
UR - https://www.ndt.net/?id=29535
AN - OPUS4-60980
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schulz, Wencke
T1 - Corrosion induced alloy sulfidation in a high-entropy alloy (HEA)
N2 - To apply high-entropy alloys (HEA) of the CrMnFeCoNi family in challenging atmospheres, their degradation behavior under harsh environments needs to be investigated. Oxidation studies to HEAs have not been extensively investigated and most of them are concentrated on environments like synthetic air, laboratory air, CO/CO2, O2 and H2O atmospheres. Main corrosion products which were identified after aging times of up to 100 h are Mn2O3 (≤800°C) and Mn3O4 (≥800°C).
Another corrosive medium in high temperature applications is SO2, which preferentially forms sulfides on commercial steels for example. These can be occurred both in the oxide layer and at the oxide/metal interface. For instance, on Fe-Cr based alloys sulfides (Cr5S6) were detected along grain boundaries and their number increases with exposure time and Cr-content in the alloy. These sulfides show an increased hardness, compared to the bulk alloy, and cause an embrittlement of the grain boundaries. This is a serious material degradation phenomenon, now addressed for the case of HEAs.
In the present study metal sulfides were identified after corrosion of the HEA CrMnFeCoNi alloy in an Ar-0.5vol.%SO2 atmosphere at 800°C for 24 h, 48 h, 96 h and 192 h exposure time. After all three duration times, a thin non-protective Cr2O3 layer has formed at the oxide/alloy interface. At the gas side a thick Mn3O4 layer with local voids containing sulfur could be detected by SEM-EDS analysis. Furthermore, S precipitates could be detected in the bulk material near the surface. These sulfides were characterized in detail by scanning and transmission electron microscopy. Based on these results, a model for grain boundary sulfidation of high-entropy alloy CrMnFeCoNi is discussed.
T2 - EUROMAT 2021 EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES
CY - Online meeting
DA - 13.09.2021
KW - High-entropy alloys
KW - High-temperature corrosion
KW - Sulfidation
KW - Chromium oxide
KW - Manganese oxide
PY - 2021
AN - OPUS4-53455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - Creep Properties of the Refractory Chemically Complex AlMo 0.5 NbTa 0.5 TiZr Alloy
N2 - The development of refractory CCAs has been explored for potential use in high temperature applications. An example of this is the AlMo0.5NbTa0.5TiZr alloy, which resembles the well-known γ/γ’ microstructure in Ni-Base superalloys with cuboidal particles embedded in a continuous matrix. The aim of this work is to evaluate the alloy’s mechanical behavior under tension in the temperature range 800-1000°C, by applying creep tests under vacuum (excluding oxidation effects). Some little temperature influence on minimum creep rate @ 1000 and 1100 °C was found and at a first glance, and Norton plots shows that deformation is probably both diffusion and dislocation controlled. However, further work is needed to stablish deformation and degradation micro mechanisms in the studied creep regime.
T2 - SPP Kick-Off Meeting 2nd Phase
CY - Online meeting
DA - 14.04.2021
KW - Creep behavior
KW - Chemically complex alloy
KW - Microstructure
PY - 2021
AN - OPUS4-53389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Agudo Jácome, Leonardo
T1 - Revealing the Nature of Melt Pool Boundaries in Additively Manufactured Stainless Steel by Nano-sized Modulation
N2 - Additive manufacturing (AM) of metallic alloys has gained momentum in the past decade for industrial applications. The microstructures of AM metallic alloys are complex and hierarchical from the macroscopic to the nanometer scale. When using laser-based powder bed fusion (L-PBF) process, two main microstructural features emerge at the nanoscale: the melt pool boundaries (MPB) and the solidification cellular substructure.
Here, details of the MPB are revealed to clearly show the three-dimensional nature of MPBs with changes of cell growth of direction and their relation to their surrounding cellular substructure, as investigated by transmission electron microscopy (TEM) for L-PBF 316L austenitic stainless steel (cf. Figure 1). A hitherto unknown modulated substructure with a period of 21 nm is further discovered within cells as the result of a partial Ga+-focused ion beam-induced ferritic transformation of the austenite. Cell cores and cell boundaries differ notably regarding the modulated substructure.
T2 - 3. Fachtagung Werkstoffe und Additive Fertigung 2022
CY - Dresden, Germany
DA - 11.05.2022
KW - Additive manufacturing
KW - Austenitic steel 316L
KW - Melt pool boundary
KW - Microstructural characterization
KW - Transmission electron microscopy
PY - 2022
AN - OPUS4-54836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Muguruza, A.R.
A1 - Odyniec, M.L.
A1 - Manhota, M.
A1 - Habib, Z.
A1 - Rurack, Knut
A1 - Blair, J.M.A.
A1 - Kuehne, S.A.
A1 - Walmsley, A.D.
A1 - Pikramenou, Z.
T1 - Antibiotic entrapment in antibacterial micelles as a novel strategy for the delivery of challenging antibiotics from silica nanoparticles
N2 - Silica materials are popular in biomedical applications as composites and drug delivery platforms due to their low toxicity and biocompatibility. Mesoporous silica nanoparticles are attractive drug delivery systems based on their porous silica framework with high surface area. In the preparation of mesoporous silica frameworks, most commonly, MCM-41, the efficient removal of the template responsible for introducing porous networks, cetyltrimethyl ammonium bromide (CTAB), is a critical step due to the template’s high toxicity in the environment and human health. In this work, we present a new one-pot approach of introducing challenging antibiotics within a silica framework without the need of toxic templates, but instead using micelle formation by an antibacterial agent. We demonstrate that micelles formed by cetylpyridinium chloride (CPC), a known antibacterial agent, entrap antibiotics such as rifampicin and ciprofloxacin. Extensive NMR studies elucidate the precise localisation of the antibiotic within the CPC micelle. Ciprofloxacin is placed between the outer and palisade region while rifampicin is located further into the hydrophobic CPC micelle core. In both cases, the formation of the silica framework can be built around the CPC-antibiotic loaded micelles. The resulting silica nanoparticles show loading of both CPC and antibiotic agents, porosity and dual antibacterial release upon disruption of the micelle within the silica framework. The design not only provides a strategy of a therapeutic design to form porous frameworks but also highlights the potential of precise antibiotic dose and release in nanoparticle systems.
KW - Silica
KW - Nanoparticles
KW - Antibiotics
KW - Drug delivery
KW - Surfactants
PY - 2024
DO - https://doi.org/10.1016/j.micromeso.2023.112841
SN - 1387-1811
VL - 363
SP - 1
EP - 11
PB - Elsevier Inc.
CY - Amsterdam
AN - OPUS4-58534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weinel, Kristina
T1 - Electron-beam-induced synthesis and characterization of disordered plasmonic gold nanoparticle assemblies
N2 - Several studies have been shown that the electron beam can be used to create nanomaterials from microparticle targets in situ in a transmission electron microscope (TEM). Here, we show how this method has to be modified in order to synthesize plasmonic gold nanoparticles (NPs) on insulating silicon oxide substrate by employing a scanning electron microscope with a comparatively low acceleration voltage of 30 kV. The synthesized NPs exhibit a random distribution around the initial microparticle target: Their average size reduces from 150 nm to 3 nm with growing distance to the initial Au microparticle target. Similarly, their average distance increases. The synthesized NP assemblies therefore show distinctly different plasmonic behaviour with growing distance to the target, which allows to study consequences of random hybridization of surface plasmon in disordered system, such as Anderson localization. To reveal the surface plasmons and their localization behaviour we apply electron energy loss spectroscopy in the TEM.
T2 - DPG spring conference, condensed matter section
CY - Berlin, Germany
DA - 17.03.2024
KW - Scanning electron microscopy
KW - Gold nanoparticle synthesis
KW - Disordered assemblies
KW - Localized plasmons
PY - 2024
AN - OPUS4-59763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - High temperature oxidation of CrFeNi in synthetic air
N2 - The surface corrosion behaviour is a key issue which determines whether the material is applicable at a given atmosphere. Medium-entropy alloy FeCrNi alloy was exposed to synthetic air at 1000°C, 1050°C, and 1100 °C for up to 1000 h using a thermobalance. The oxidation rate was parabolic at 1000 and 1050°C, but breakaway occurred at 1100°C after 5 h of aging time. The whole oxide scales formed under the isothermal oxidation tests spalled off and additional oxidation tests were carried out at 1000 °C and 1050°C for 24 h and up to 100 h at 1000°C in a tubular furnace. The corrosion behaviour of the MEA was analysed by scanning electron microscope, energy-dispersive X-ray spectroscopy, and X-ray diffraction and compared to the behaviour of 316 L. The experimental results showed that under all conditions chromium is the main diffusion element resulting in the formation of a Cr2O3 layer at the MEA surface. Spallation of the layer induces the formation of additional oxidation products under the surface of the (spalled off) chromia layer.
T2 - Euromat 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Medium entopy alloy
KW - Oxidation
KW - Scanning electron microscopy
KW - Thermogravimetric analysis
PY - 2023
AN - OPUS4-58198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Noch ein Normungsausschuss? Was hinter dem neuen Tribologie-Ausschuss beim DIN steckt
N2 - Am 10. März fand die Gründungssitzung des neuen DIN-Ausschusses NA 062-10-21 AA "Tribologie" statt. Er fokussiert den praxisnahen Wissenstransfer zur Lösung aktueller Herausforderungen und beschäftigt sich mit Querschnittsthemen sowie übergreifenden Aspekten. Der Vortrag informiert über den Kontext der Gründung und stellt die ersten Normungsprojekte vor.
T2 - 66. GfT Tribologie-Fachtagung 2025
CY - Wernigerode, Germany
DA - 01.10.2025
KW - Tribologie
KW - DIN
KW - Normung
KW - Standardisierung
KW - Harmonisierung
KW - FAIR
KW - Verschleißermittlung
KW - Oberflächencharakterisierung
KW - Terminologie
KW - Ontologie
KW - Semantik
KW - Datenbank
KW - Dataspace
PY - 2025
AN - OPUS4-64252
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lazurenko, D.V.
A1 - Laptev, I.S.
A1 - Golkovsky, M.G.
A1 - Stark, A.
A1 - Paul, J.
A1 - Bataev, I.
A1 - Ruktuev, A.A.
A1 - Song, L.
A1 - Gollwitzer, Christian
A1 - Pyczak, F.
T1 - Influence of the Ti/Al/Nb ratio on the structure and properties on intermetallic layers obtained on titanium by non-vacuum electron beam cladding
N2 - Ti-Al-Nb based intermetallic layers of sufficient quality and thickness were obtained by non-vacuum electron beam cladding on the surfaces of Ti workpieces. Optical microscopy and X-ray tomography did not reveal any dramatical defects in the structure of cladded layers. X-ray diffraction as well as scanning and transmission electron microscopy were applied to thoroughly investigate the structure and phase composition of coatings. It was found that non-equilibrium cooling conditions of coatings provided by fast removal of heat to untreated Ti substrate after the electron beam cladding was terminated induced the proceeding of metastable phase transformations. For example, γ-phase formation was suppressed in these coatings. In coatings with 8 and 20 at.% Nb (46 and 43% Al respectively) along with ordered with α2, formation of disordered solution of the alloying elements in α-Ti took place. In high-Nb alloys β(B2) phase has undergone the diffusionless transformation to ω’, which is the intermediate phase in β → ω and the coating with the maximum Nb content characterized by appearance of γ1 as a main phase. ω-phase had negative influence to hardness and wear resistance of coatings, however, generally this paremeter increased in 1.3–1.75 times compared to cp-Ti. The high temperature creep and oxidation properties decreased proportionally with increasing Nb and decreasing Al content in the cladded layers.
KW - Electron beam cladding
KW - Titanium aluminides
KW - Metastable phases
KW - Diffraction analysis
KW - Wear
KW - High-temperature properties
PY - 2020
DO - https://doi.org/10.1016/j.matchar.2020.110246
SN - 1044-5803
VL - 163
SP - 110246
PB - Elsevier Inc.
AN - OPUS4-50550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Gollwitzer, Christian
A1 - Kupsch, Andreas
A1 - Léonard, Fabien
A1 - Müller, Bernd R.
A1 - Oesch, Tyler
A1 - Onel, Yener
A1 - Thiede, Tobias
A1 - Zscherpel, Uwe
ED - Puente León, F.
ED - Zagar, B.
T1 - Moderne Methoden der CT-gestützten Strukturanalyse
T1 - Modern techniques of CT based structure analysis
N2 - Durch den großflächigen Einsatz der Computertomographie (CT) in unterschiedlichen Industriebereichen steigen auch die Anforderungen an die quantitative Bildanalyse. Subjektive Bildwahrnehmung muss durch objektive Algorithmen ersetzt werden. In diesem Artikel stellt die Bundesanstalt für Materialforschung und -prüfung (BAM), die seit den 1980er Jahren an der Entwicklung der industriellen CT beteiligt ist, anhand ausgewählter Beispiele den aktuellen Stand ihrer Analysemethoden an verschiedenen Anwendungsbeispielen der CT vor.
N2 - The increasing use of computed tomography (CT) in various industrial sectors requires more sophisticated techniques of quantitative image analysis. Subjective image perception needs to be replaced by objective algorithms. The German Federal Institute for Materials Research and Testing (BAM) has been involved in the development of industrial CT since the 1980s. This paper summarizes the current status of quantitative 3D image analysis techniques based on selected examples.
KW - Computed tomography
KW - Computertomographie
KW - Röntgen-Refraktion
KW - X-Ray refraction
KW - Schadensanalyse
KW - Damage analysis
KW - Normung
KW - standardization
PY - 2020
DO - https://doi.org/10.1515/teme-2019-0125
SN - 0171-8096
SN - 2196-7113
VL - 87
IS - 2
SP - 81
EP - 91
PB - de Gruyter
CY - Berlin
AN - OPUS4-50337
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
T1 - Untersuchung der Integrität von glasfaserverstärkten Zahnstiften mittels Synchrotron-Röntgenrefraktion
N2 - Die Integrität der Verstärkungsfasern in Komposit-Zahnstiften ist entscheidend für die Biegefestigkeit und die langfristige Haftung am Zement in den Wurzelkanälen. Es wurde vermutet, dass die Integrität von glasfaserverstärkten Zahnstiften durch das Beschleifen während der zahnmedizinischen Behandlung beeinträchtigt wird. Eine Beschädigung der Fasern führt zu einer erheblichen strukturellen Schwächung über den gesamten Stiftdurchmesser. Glasfragmente, die durch den Kontakt mit dem Zahnbohrer entstehen, können sich vom Stift lösen und die Haftfähigkeit erheblich verringern. Mit Hilfe hochauflösender Synchrotron-Röntgen-Refraktions-Radiographie (SXRR) konnte das Ausmaß der Schäden zuverlässig identifiziert und charakterisiert werden.
Dazu wurden die Glasfaserstifte sowohl im Herstellungszustand als auch nach der Bearbeitung mit einem Diamantbohrer untersucht. Die Datensätze wurden zur Visualisierung und Quantifizierung der morphologischen Charakteristika intakter und durch das Beschleifen beschädigter Regionen analysiert. Sie zeigen Schäden im bearbeiteten Bereich (z. B. Brüche, Splitter und Risse) sowie herstellungsbedingte Inhomogenitäten der Fasern mit einer signifikanten Zunahme der inneren Oberflächen in Probenregionen, die durch das Beschleifen beschädigt wurden.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Röntgen-Refraktion
KW - Verbundwerkstoffe
KW - Zahnstifte
PY - 2022
AN - OPUS4-54924
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hörmann, Anja F.
A1 - Simon, Miriam
A1 - Brückner, Christoph
A1 - Rogers, Sarah E.
A1 - Porcar, Lionel
A1 - Hoffmann, Ingo
A1 - Gradzielski, Michael
T1 - Line tension controls the spontaneous formation of vesicles
N2 - Mixtures of the zwitterionic surfactant TDMAO and the anionic surfactant LiPFOS spontaneously self-assemble into well defined vesicles. The size of these vesicles is determined by the ratio of bending rigidity and line tension. By partially charging TDMAO, and thereby moving more to a catanionic system, the size of these vesicles can be controlled. Using stopped flow small angle neutron scattering we monitor the kinetics of vesicle formation and obtain their final size. Neutron spin echo spectroscopy allows for an independent measurement of the vesicle’s bending rigidity. Combining this bending rigidity with the radius of newly formed vesicles, which is determined by the ratio of bending rigidity and line tension, we can determine the line tension. We find that it is the line tension that controls the trend in size of the vesicles. In summary, this means that here one has a surfactant mixture that delivers well-defined vesicles, whose size is controlled by the electrostatic interactions of the head groups.
KW - Self-assembly
KW - Small unilamellar vesicles
KW - Small-angle neutron scattering
KW - Line tension
KW - Neutron spin-echo spectroscopy
KW - Stopped-flow
KW - Bending rigidity
KW - Surfactant mixture
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646964
DO - https://doi.org/10.1039/D5SM00600G
SN - 1744-683X
VL - 21
IS - 43
SP - 8360
EP - 8367
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64696
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A. I.
A1 - Nolze, Gert
A1 - Malakhov, A. Yu.
A1 - Pervukhina, O. L.
T1 - Investigation of the Structure of Interfaces Between Metals and Alloys Joined by Explosion Welding
N2 - The structure of interfaces in Fe20Cr6Al/Cu, titanium/steel and brass/Invar bimetals obtained by explosion welding from sheet components with a thickness of 1 and 4, 25 and 5, 12 and 8 mm, respectively, was studied using analytical methods of scanning electron microscopy. The wave dimensions (length/height) were approximately 200/50 μm for Fe20Cr6Al/Cu, 700/70 μm for titanium/steel and 350/100 μm for brass/Invar. At the micron scale, mutual penetration of the welded components into each other (trans-interface diffusion) was not detected. In the iron-based plate of Fe20Cr6Al/Cu bimetal, a strong texture and cracks, which are a critical defect, were formed as a result of severe plastic deformation. Less pronounced textures were revealed in the components of titanium/steel bimetal. In titanium/steel bimetal, Laves phase particles Fe2Ti were found near the welded interface, while in brass/Invar bimetal, local contact melting was observed. However, the particles Fe2Ti and local melting areas are not critical defects, as they do not cause unacceptable deterioration in the adhesive strength of the welded joints, which was confirmed by a high shear strength of 500-570 MPa for the brass/Invar bimetal.
KW - EBSD
KW - Welding
KW - Interface
PY - 2025
DO - https://doi.org/10.1007/s11665-025-12660-x
SN - 1059-9495
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-64732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rechlin, J.
A1 - Soni, Akshar
T1 - SimuCrown: Die Simulation der funktionellen Alterung – Wege zur Vorhersage von Misserfolgen dentaler Kronenrestaurationen in vitro
N2 - Bei der Versorgung von Zähnen mit dentalen Kronenrestaurationen entsteht ein Kronen-Zement-Zahn-Komplex (KZZK). Dentale Werkstoffe überzeugen mit besten Materialeigenschaften, aber wie funktionieren sie im Verbund? Unsere zentrale Annahme lautet, dass die Alterung des KZZK eine zentrale Rolle bei Misserfolgen spielt. Präsentiert werden die Methodik und Bilder der ersten Arbeitsphase.
T2 - Gemeinsame Jahrestagung der Deutschen Gesellschaft für Zahnerhaltung (DGZ) und der Deutschen Gesellschaft für Prothetische Zahnmedizin und Biomaterialien e.V. (DGPro)
CY - Leipzig, Germany
DA - 13.06.2024
KW - Kronen-Zement-Zahn-Komplex
KW - Funktionelle Alterung
KW - Computertomographie
PY - 2024
AN - OPUS4-60776
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Homann, Christian
A1 - Peeters, Régis
A1 - Mirmajidi, Hana
A1 - Berg, Jessica
A1 - Fay, Michael
A1 - Rodrigues, Lucas Carvalho Veloso
A1 - Radicchi, Eros
A1 - Jain, Akhil
A1 - Speghini, Adolfo
A1 - Hemmer, Eva
T1 - Rapid microwave-assisted synthesis of morphology-controlled luminescent lanthanide-doped Gd2O2S nanostructures
N2 - Gadolinium oxysulfide (Gd2O2S) is an attractive material of demonstrated suitability for a variety of imaging applications, leveraging its magnetic, scintillating, and luminescent properties, particularly when doped with optically active lanthanide ions (Ln3+). For many of these applications, control over size and morphology at the nanoscale is crucial. This study demonstrates the rapid microwave-assisted Synthesis of colloidal Ln2O2S (Ln = Gd and dopants Yb, Er, Tb) nanostructures in as little as 20 min. Structural characterization using X-ray diffraction analysis (XRD), Raman spectroscopy, as well as Transmission electron microscopy (TEM), including elemental mapping via energy dispersive X-ray spectroscopy (EDS), unveiled the key role of elemental sulphur (S8) in the reaction mixtures for materials growth. By systematically varying the Ln-to-S ratio from 1 : 0.5 to 1 : 15, controlled morphologies ranging from triangular nanoplatelets to berry- and flower-like shapes were achieved. Doping with Er3+/Yb3+ endowed the nano-triangles with upconverting and near-infrared emitting properties. Tb3+-doped Gd2O2S exhibited the characteristic green Tb3+ emission under UV excitation, while also showing X-ray excited optical luminescence (XEOL), rendering the material interesting as a potential nano-scintillator.
KW - Upconversion
KW - Microwave-assisted synthesis
KW - Synthesis
KW - Fluorescence
KW - Nano
KW - Particle
KW - NIR
KW - XRD
KW - X-ray fluoressence
KW - Morphology control
KW - Raman
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647907
DO - https://doi.org/10.1039/D5TC01646K
SN - 2050-7526
VL - 13
IS - 35
SP - 18492
EP - 18507
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bauer, L.
T1 - Complementary X-ray techniques reveal hidden details in dental materials
N2 - In dentistry it is of great interest to achieve good sealing interzones between tooth tissue and restoration materials to avoid, e. g. secondary caries. μXRF and CμXRF are suitable to investigate the elemental composition at these interzones in respect to diffusion of elements. Synchrotron X-ray refraction radiography (SXRR) and μCT measurements deliver highly resolved structural information and make structural changes such as micro cracks within the filling and the tooth tissue visible. The presented measurements are part of the DFG funded project IXdent (Integrative X-ray techniques for chemical and structural characterizations of dental interzones.)
The depth-resolved CμXRF measurements are affected by absorption effects, making a quantitative investigation of the interzone in depth difficult. Full 3D quantification of heterogenous samples requires a complete model including dark matrix and density for each voxel. The combination of different techniques paves the way for a quantitative analysis of dental interzones.
T2 - 15th BESSY@HZB User Meeting
CY - Berlin, Germany
DA - 22.06.2023
KW - X-ray refraction
KW - X-ray fluorescence
KW - Computed tomography
KW - Dental material
PY - 2023
AN - OPUS4-57849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
T1 - Fit für die Zukunft –Thermografie und aktuelle Normen
N2 - Normung und Standardisierung schaffen die technische, rechtliche und wirtschaftliche Grundlage, um neue zerstörungsfreie Prüftechnologien wie die Thermografie erfolgreich in industrielle Anwendungen zu überführen. Ohne einheitliche Standards fehlt es an Vertrauen, Vergleichbarkeit und Kompatibilität, was die Akzeptanz und Verbreitung neuer Verfahren erheblich hemmt.
T2 - Thermo 25
CY - Garching bei München, Germany
DA - 12.11.2025
KW - Thermografie
KW - Normen
KW - Standards
PY - 2025
AN - OPUS4-64830
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna
T1 - High-temperature in-situ investigation of refractory high entropy superalloys
N2 - The spinodal decomposition in bcc structured refractory alloys can be used as a potential strengthening mechanism, as has been demonstrated over the last decade in research on high entropy alloys and compositionally complex alloys. Early work from the 1990s already showed the possibility of further enhancing this spinodal decomposition by adding the element Al, which in addition to spinodal decomposition also provides an ordering process in the otherwise disordered bcc phases of the alloy. Nevertheless, the knowledge of refractory high entropy (super)alloy systems, is still in its infancy and requires further research to fully exploit its potential for high temperature applications in the future.
Two refractory alloys of the Al-Nb-Ta-Ti-Zr family are investigated via (high temperature in-situ) XRD, in the long run for understanding spinodal decomposition properties. Ex-situ XRD and TEM observations show the formation of at least one bcc phase and an ordered B2 phase. In addition, one or more Al-Zr rich phases are observed, which are not part of the spinodal phases and are unwanted.
The high-temperature observations at 1000°C for 60 h show a remarkable increase in peak width up to 2° FWHM that does not disappear after cooling in the furnace. Ex-situ observations after 1000°C for hundreds of hours and subsequent quenching show narrow peaks (max 0,2° FWHM) at the same position. This and several other observations will be presented in this talk and possible explanations are presented.
T2 - Euromat 2025
CY - Granada, Spain
DA - 14.09.2025
KW - High-entropy alloys
KW - Superalloys
KW - X-ray diffraction
KW - In-situ
KW - Scanning electron microscopy
PY - 2025
AN - OPUS4-64840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adamski, Paweł
A1 - Zgrzebnicki, Michał
A1 - Albrecht, Aleksander
A1 - Jurkowski, Artur
A1 - Wojciechowska, Agnieszka
A1 - Ekiert, Ewa
A1 - Sielicki, Krzysztof
A1 - Mijowska, Ewa
A1 - Smales, Glen J.
A1 - Maximenko, Alexey
A1 - Moszyński, Dariusz
T1 - Ammonia synthesis over γ-Al2O3 supported Co-Mo catalysts
N2 - Novel ammonia synthesis catalysts are sought due to energetic transformation and increasing environmental consciousness. Materials containing cobalt and molybdenum are showing state-of-art activities in ammonia synthesis. The application of γ-alumina support was proposed to enhance the properties of Co-Mo nanoparticles. The wet impregnation of the support was conducted under reduced pressure. The active catalysts were obtained by ammonolysis of precursors. The chemical and phase composition, as well as morphology, porosity, and surface composition of precursors and catalysts, were characterized. The Co-Mo nanoparticles phase composition as well as their size and dispersion were determined using X-ray absorption spectroscopy utilizing synchrotron radiation, electron microscopy, and X-ray scattering. The catalytic activity was tested in the ammonia synthesis process under atmospheric pressure. The activity and stability of the supported catalysts were compared with unsupported cobalt molybdenum nitride Co3Mo3N, revealing the superiority of the present approach.
KW - Ammonia synthesis
KW - Supported catalyst
KW - Cobalt molybdenum nitrides
KW - Scattering
KW - X-ray scattering
KW - Gamma-alumina
KW - Stability
PY - 2025
DO - https://doi.org/10.1016/j.mcat.2025.114907
SN - 2468-8231
VL - 575
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-64827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gottschalk, Götz-Friedrich
A1 - Chaurasia, Prashant Kumar
A1 - Goecke, Sven-Frithjof
T1 - Zero-defect Printing with DED-GMA via Adaptive Controls
N2 - Gas metal arc assisted directed energy deposition (DED-GMA) is a metal additive manufacturing process for fabricating large-scale parts with a higher printing rate. An accurate monitoring and control of the melt pool geometric features is critical for printing zero-defect parts. In this study, the melt pool thermography is used for the real-time detection of the melt pool boundary, centreline, and transient cooling time using an efficient deep learning technique. The presented real-time process monitoring and control methodology using deep learning allows adaptive control of the DED-GMA process.
T2 - Twenty-Second International Conference on Flow Dynamics (ICFD 2025)
CY - Sendai, Japan
DA - 10.11.2025
KW - Additive manufacturing
KW - DED-Arc
KW - Monitoring
KW - Control
PY - 2025
SP - 1332
EP - 1335
AN - OPUS4-64837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Cakir, Cafer Tufan
A1 - Kasatikov, S.
A1 - Schumacher, G.
A1 - Manzoni, Anna Maria
T1 - Effects of heat treatment on microstructure, hardness and local structure in a compositionally complex alloy
N2 - Unlike conventional alloys, high entropy alloys are characterized by one or more solid solution phase(s) without a clearly defined solvent, all element contribute to the matrix in a way that is still not entirely understood. In addition, it is not known to what extent classic thermodynamic rules can be applied to these multi-element alloys, especially concerning the question about what factor incites the matrix to undergo a phase transformation.
This work tackles directly some of these aspects on a chosen alloy, Al8Cr17Co17Cu8Fe17Ni33 (at.%), which presents a high temperature single-phase γ state and a two-phase state with γ′ precipitates, above and below 900 ◦C, respectively. A combined investigation via microstructural observations, hardness testing, X-ray absorption and photoelectron spectroscopy was carried out above the γ′ formation temperature. Hardness values are independent of the annealing temperatures, microstructural analysis shows no phase formation and X-ray absorption spectroscopy does not reveal observable changes in neither local atomic nor electronic structure, indicating that approaching γ′ formation temperature is not influenced by atomic or electronic rearrangements.
Interestingly, short-range chemical order remains quantitatively compatible at any annealing temperature in the single-phase γ state, and the observed preferred pairs Al–Cu and Al–Ni in the γ state match with the γ’ precipitates composition below 900 ◦C.
KW - High entropy alloys
KW - EXAFS
KW - Short range order
KW - Vickers hardness
PY - 2022
DO - https://doi.org/10.1016/j.matchemphys.2021.125432
SN - 0254-0584
VL - 276
SP - 125432
PB - Elsevier B.V.
AN - OPUS4-53760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - High temperature and low stress creep behavior of the refractory chemically complex alloy AlMo 0.5 NbTa 0.5 TiZr
N2 - The refractory chemically complex alloy (rCCA) AlMo0.5NbTa0.5TiZr, with a density of 7.4 g/cm3, shows a compressive ultimate strength of 772 MPa at 1000 °C, comparatively surpassing Ni-base and other rCCAs. Its dual-phase microstructure, with a high volume fraction (≈ 62%) of cuboidal and plate-like particles coherently embedded in a continuous matrix, resembles the well-known pattern of the γ/γ" in Ni-base superalloys. Its developers have thus implied that it could stand as structural alloy for high temperature (HT) applications. Here, we report the HT creep properties and the underlying microstructural changes of the rCCA AlMo0.5NbTa0.5TiZr to propose deformation and degradation micromecanisms for this regime. The material was produced by arc-melting and subsequently heat treated in argon: at 1400 °C for 24 h plus a hot isostatic pressure treatment at 1370 °C and 170 MPa for 4 h, with a cooling rate of 10 K/min. Miniaturized tensile specimens (≈ 28 x 7 x 2 mm) were cut and polished to a quality of 1 μm. Creep tests were conducted in vacuum in the respective temperature and stress range 800-1200 °C and 30-120 MPa. For observation, thin slices were extracted from the gauge length, away from the fracture surface, grinded to a thickness of 100 μm, and electropolished to electron transparency. The microstructure was observed on the electropolished specimens using scanning (S) as well as transmission (T) electron microscopy (EM). The Norton plot gives Norton exponents of about 3.1 and 3.2 for temperatures of 1000 and 1100 °C, respectively. Curiously, creep rate minima are very close for a stress level of 30. The starting microstructure reflects a macroscopically lean coarse grain structure and a microscopically fine-meshed basketweave structure with coherency dislocations only around coarsened particles usually close to subgrain boundaries. Results are discussed on the base of variations of this starting microstructure after interrupted and ruptured creep tests.
T2 - 15th International Conference on Creep and Fracture of Engineering Materials and Structures
CY - Online meeting
DA - 14.06.2021
KW - Creep behavior
KW - Chemically complex alloy
KW - Cow stress
PY - 2021
AN - OPUS4-53388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - Effect of the heat treatment in the microstructure of a refractory chemically complex alloy
N2 - A set of some unexpected and interesting microstructures has put the so-called complex concentrated alloys (CCAs) in the eye of the scientific community. The AlMo0.5NbTa0.5TiZr refractory (r)CCA, aimed at substituting Ni-base superalloys in gas turbine applications, belongs to this alloy family. After a two-stage heat treatment, this rCCA morphologically resembles the typical a two-phase microstructure of the latter. The objective of this work consists in determining the effect of the two stages of the heat treatment on the microstructure of the AlMo0.5NbTa0.5TiZr alloy to eventually improve it in terms of homogeneity and porosity.
T2 - Third International Conference on High Entropy Materials (2020)
CY - Berlin, Germany
DA - 27.09.2020
KW - Annealing
KW - Hot isostatic pressing
KW - Refractory chemically complex alloy
KW - Microstructure
PY - 2020
AN - OPUS4-53386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Reliable welding of high-entropy alloys
N2 - The importance of high-entropy alloy (HEAs) in the field of materials research is increasing continuously and numerous studies have been published, recently. These are mainly focused on manufacturing of different alloy systems having excellent structural properties from low to high temperatures. Therefore, HEAs are of high potential for many applications in very demanding conditions. However, this is so far limited by poor knowledge and experience regarding economic and reliable component manufacturing. The processability of HEAs has hardly been investigated so far, indicated by the small number of publications worldwide: welding <30 and machining <5.
Hence, this contribution provides an overview about the current state of the art on processing of HEAs. Fundamental principles are shown for safe weld joints while ensuring high component integrity. For safe welding, the combined consideration of complex interactions of material, construction and process is necessary. Recent studies on different HEAs showed the influence of heat input by means of different welding processes on the microstructure and respective properties. Based on intensive literature survey and on our initial study, the main research objectives of processing HEAs are presented.
T2 - ICHEM 2020 - Third International Conference on High Entropy Materials
CY - Berlin, Germany
DA - 27.09.2020
KW - High Entropy Alloy
KW - Welding
KW - Welding processing influences
PY - 2020
AN - OPUS4-51591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cornelsen Sampaio Kling, I.
A1 - Pauw, Brian Richard
A1 - Agudo Jácome, Leonardo
A1 - Archanjo, B. S.
A1 - Simão, R. A.
T1 - Development and characterization of starch film and the incorporation of silver nanoparticles
N2 - Starch is one of the biopolymers being used for bioplastic synthesis. For production, starch can be combined with different plasticizers, starches from different plant sources and even with nanomaterials to improve or to add film properties. The challenge of adding these, e.g. in the form of silver nanoparticles (AgNp) is to determine the concentration so as to avoid impairing the properties of the film, agglomeration or altering the visual characteristics of the film. In this study, a starch film synthesis route and the incorporation of silver nanoparticles has been proposed in order not to alter the properties of the film while maintaining the transparency and a clear colour of the starch film. The results showed that the proposed synthesis route is promising, efficient, reproducible, fast and the film has good mechanical properties.
T2 - Semana MetalMat & Painal PEMM 2020
CY - Online meeting
DA - 23.11.2020
KW - Biofilm
KW - Silver nanoparticle
KW - Starch
KW - Starch nanoparticle
PY - 2020
SP - 1
EP - 2
AN - OPUS4-51940
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Tuning high entropy alloys towards superalloy applications
N2 - The discovery of the high entropy concept at the beginning of the 3rd millennium lead to a worldwide increase in metallurgical research, as the possible element combinations seemed nearly endless and the range of applications wide. In the early years of research, one of the main goals was the discovery of a single-phase high entropy alloy. As research evolved, it was found that properties could be enhanced by opening the HE-concept towards multiphase alloys, and from the wide area of possibilities our group chose a tuning of the properties towards high temperature application.
Compositionally complex Al10Co25Cr8Fe15Ni36Ti6 alloy, which is single-phase at high temperature, around 1200°C, shows a three phase morphology at intermediate temperatures, around 800°C. A high temperature homogenization procedure has to be applied in order to decrease the segregation induced by the dendritic growth. Subsequent annealing promotes the formation of the strengthening γ' precipitates. The alloy shows a positive lattice misfit between the γ and the γ' phase, which can be an indicator for good creep properties.
The microstructure can be optimized by adding trace elements such as Mo and Hf, known as γ and γ' strengtheners in Ni-based superalloys, respectively. Atom probe measurements show that Mo segregates into the γ matrix, and Hf prefers the γ' precipitates, where it increases the lattice parameter and thus also the lattice misfit, by about 50%. The alloy family shows interesting mechanical properties, especially the Al9.5Co25Cr8Fe15Ni36Ti6Hf0,5 alloy – its tensile properties are better than those of commercial Alloy 800H and IN617 at temperatures up to 700°C.
T2 - BAM Abteilungsseminar
CY - Online meeting
DA - 21.01.2021
KW - High entropy alloys
KW - Compositionally complex alloys
KW - Superalloys
KW - Hochentropie-Legierung
KW - Legierung mit komplexer Zusammensetzung
KW - Superlegierung
PY - 2021
AN - OPUS4-52442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kling, I. C. S.
T1 - Development and characterization of starch film and the incorporation of silver nanoparticles
N2 - Starch is one of the biopolymers being used for bioplastic synthesis. For production, starch can be combined with different plasticizers, starches from different plant sources and even with nanomaterials to improve or to add film properties. The challenge of adding these, e.g. in the form of silver nanoparticles (AgNp) is to determine the concentration so as to avoid impairing the properties of the film, agglomeration or altering the visual characteristics of the film. In this study, a starch film synthesis route and the incorporation of silver nanoparticles has been proposed in order not to alter the properties of the film while maintaining the transparency and a clear colour of the starch film. The results showed that the proposed synthesis route is promising, efficient, reproducible, fast and the film has good mechanical properties.
T2 - Semana MetalMat & Painal PEMM 2020
CY - Online meeting
DA - 23.11.2020
KW - Biofilm
KW - Starch
KW - Starch nanoparticle
KW - Silver nanoparticle
PY - 2020
AN - OPUS4-51828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Manzoni, Anna Maria
T1 - Combining trace elements for microstructural optimization in the Al10Co25Cr8Fe15Ni36Ti6 compositionally complex alloy
N2 - Trace elements W and Hf have different influence on the microstructure and the mechanical properties when added to the Al10Co25Cr8Fe15Ni36Ti6 compositionally complex alloy. The addition of both can thus merge both element’s beneficial influences when combined with the appropriate heat treatment: Hf enhances the cubicity of the γ’ particles in the γ matrix while the W reduces the negative influence of the Heusler phase: this phase can be completely dissolved when W is present in the alloy.
T2 - ICHEM 2020
CY - Berlin, Germany
DA - 27.09.2020
KW - High entropy alloys
KW - Transmission electron microscopy
KW - Lattice misfit
KW - X-ray diffraction
KW - Scanning electron microscopy
PY - 2020
AN - OPUS4-51370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sonnenburg, Elke
T1 - Präparation, Kontrastierung und Darstellung des Gefüges von additiv gefertigtem austenitischem Stahl 316L
N2 - Der weit verbreitete austenitische Stahl 316L soll auch mittels additiver Fertigung verarbeitet werden (316L-AM). Zur Entwicklung optimaler Aufbauverfahren ist ein detailliertes Verständnis des Gefüges notwendig. Das additiv aufgebaute Gefüge zeigt eine Mikrostruktur, die geprägt ist von sehr hohen Abkühlraten und gerichtetem Kornwachstum. Mittels klassischer Metallographie können die Charakteristika des Gefüges wie Körner, Subkörner und Schmelzlinien sichtbar gemacht werden. Mittels EBSD werden Kristallorientierungen ermittelt und bildhaft aufbereitet. Die Feinstruktur der Körner wird im REM in der Übersicht aufgelöst. Erst im TEM kann bei hoher Vergrößerung die Natur der Zellstruktur quantitativ ermittelt werden.
T2 - Metallographie 2020
CY - Online meeting
DA - 16.09.2020
KW - Präparation
KW - Kontrastierung
KW - Additiv gefertigter Stahl
PY - 2020
AN - OPUS4-51245
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, Heike
A1 - Zahedi-Azad, Setareh
A1 - Ernst, Owen C.
A1 - Lucaßen, Jan
A1 - Mann, Guido
A1 - Bonse, Jörn
A1 - Boeck, Torsten
A1 - Martin, Jens
A1 - Schmid, Martina
A1 - Krüger, Jörg
T1 - Chemical vapor deposition of indium precursors for solar microabsorbers using continuous laser radiation
BT - A, Materials science & processing
N2 - Localized deposition of indium on an amorphous glass surface covered with a thin molybdenum layer is demonstrated utilizing laser-assisted chemical vapor deposition. A continuous-wave laser causes a temperature rise on the molybdenum layer resulting in the selective aggregation of liquid and ultimately crystalline structures of indium. The formation sites of the indium are determined by the decomposition of gaseous trimethylindium. The deposited indium islands can serve as precursors and could be further processed into compound semiconductors like CuInSe2 for micro-concentrator solar cells. The experimental investigations were supported by theoretical simulations of the laser heating process to calculate the local temperature distribution on the surface of the molybdenum-covered glass substrate.
KW - Laser-assisted Chemical Vapor Deposition
KW - CW Laser
KW - Indium Islands
KW - Micro-concentrator Solar Cell
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641069
DO - https://doi.org/10.1007/s00339-025-08895-z
SN - 0947-8396
VL - 131
SP - 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg [u.a.]
AN - OPUS4-64106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - Cost action EURO MIC (CA20130)
N2 - Vorstellung des vor kurzen angelaufenen EU-Projekts: COST
ACTION EURO MIC ( CA20130). Die BAM hat hierbei die Rolle des Chairs sowie Grant-Holding Institute. COST fördert internationale Netzwerk Aktivitäten. Durch COST Action können neue Kooperationen (Industrie, Akademie oder Politk) entstehen.
T2 - Dechema
CY - Online meeting
DA - 10.11.2021
KW - Netzwerk
KW - COST
KW - Mikrobiell beeinflusste Korrosion
KW - MIC
PY - 2021
AN - OPUS4-54023
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - Mikrobiell beeinflusste Korrosion (MIC) – Wenn MIC dann BAM
N2 - In dieser Präsentation wurden dem Beirat Umwelt die High-Lights und der weitere Ausblick des Foresight Process MIC vorgestellt. Im Fokus stehen hierbei insbesondere die neu angelaufenen Projekte:
COST Action Euro-MIC
MIC im Endlager
Hydrogen: MIC & Wasserstoffversprödung
Biorezeptivität von Betonoberflächen
Mitigation schwarze Pilze
WIPANO ResTest
T2 - Beirat Umwelt
CY - Online meeting
DA - 11.03.2022
KW - MIC
KW - Hi-Tension
KW - Projekte
PY - 2022
AN - OPUS4-54463
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, Alan
A1 - Moschetti, Michael
A1 - Miskovic, David
A1 - Wei, Tao
A1 - Ionescu, Mihail
A1 - Wang, Zhiyang
A1 - Palmer, Tim
A1 - Bhattacharyya, Dhriti
A1 - He, Peidong
A1 - Li, Xiaopeng
A1 - Gludovatz, Bernd
A1 - Ferry, Michael
T1 - Improved irradiation resistance of a low activation refractory medium entropy alloy, VCrFeW0.2, for fusion applications demonstrated by micro-tensile testing
N2 - An, as cast, VCrFeW0.2 refractory medium entropy alloy (RMEA) was designed for fusion reactor divertor applications, focusing on reduced cost, low activation and compositional stability (low transmutation rates). The as-cast alloy was irradiated to a fluence of 5.6 × 10^17 ions/cm^2 at room temperature with 5 MeV helium ions whose energy have been uniformly attenuated to 0.4 MeV and 5 MeV via energy degradation device prior to sample irradiation. Pre and post irradiation, its mechanical properties were evaluated micro-tensile testing. Prior to irradiation, the VCrFeW0.2 alloy demonstrated good strength and ductility, with a yield strength of 1464 MPa and strain to UTS (\sigma_UTS) of 4.6 %, maintaining comparable strength to pure tungsten (1403 MPa) but with greater strain to UTS (1.3 %). Post irradiation, the VCrFeW0.2 alloy exhibited remarkable damage resistance; its strength increased by only ∼160 MPa, and it retained strain to UTS with a \sigma_UTS of 2.9 %. It performed better than pure tungsten tested under identical irradiation conditions where there was ∼1800 MPa increase in yield strength and a complete loss of plasticity. The micro-tensile results were supported by nanoindentation tests and Vickers hardness testing was also undertaken to show the yield strength values are representative of macro scale, bulk behavior. TEM and comparison with existing literature on RMEA/RHEA are presented here to understand the reason for difference in performance between VCrFeW0.2 alloy and pure tungsten.
KW - Refractory medium entropy alloys
KW - Fusion reactor materials
KW - Irradiation resistance
KW - Micro-tensile testing
KW - Helium ion damage
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645322
DO - https://doi.org/10.1016/j.ijrmhm.2025.107481
SN - 0263-4368
VL - 134
SP - 1
EP - 16
PB - Elsevier Ltd.
CY - Netherlands
AN - OPUS4-64532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dinter, Adelina-Elisa
T1 - Development of a single cell-ICP-ToF-MS-method for multielement analysis of MIC organisms grown on solid steel samples
N2 - The latest ICP-MS technology - ICP-ToF (time of flight)-MS – enables the analysis of the multi-element fingerprint of individual cells. The interface between material and environmental analysis thus receives special attention, e.g., when considering corrosion processes. Microbiologically influenced corrosion (MIC) is a highly unpredictable phenomenon due to the influence of the environment, microbial communities involved and the respective electron source. However, the interaction pathway between cells and the metal surface remains unclear. The development of the MIC-specific ICP-ToF-MS analytical method presented here at the single cell level, in combination with the investigation of steel-MIC interactions, contributes significantly to progress in instrumental MIC analysis and will enable clarification of the processes taking place. For this, a MIC-specific staining procedure was developed. It allows the analysis of archaea at a single cell level and provides information about the interaction of the cells with the staining agent which is extremely scarce compared to other well characterized organisms. Additionally, the single cell ICP-ToF-MS is used for the analysis of archaea involved in MIC of steel. Hence, the possible uptake of individual elements from different steel samples is investigated - the information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts, thus combining modern methods of analytical sciences with materials.
T2 - DAAS Doktorandenseminar 2021
CY - Online meeting
DA - 20.09.2021
KW - Sc-ICP-ToF-MS
KW - Single cell analysis
KW - Microbiologically influenced corrosion
KW - Archaea
PY - 2021
AN - OPUS4-53340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - COST-Action - EURO-MIC (CA20130) European MIC Network - New paths for science, sustainability and standards
N2 - Microbiologically Influenced Corrosion (MIC) is a phenomenon that is increasingly becoming a problem
for the society. MIC describes the negative effects a material can experience due to the presence of
microorganisms. In Europe, several research groups/ other industrial stakeholders are already dealing with
MIC. Unfortunately, the discussions are fragmented and the exchange of information is limited. A true
transdisciplinary approach is hardly ever experienced, although this would be logical for this
material/biology related challenge.
USA, Canada and Australia have strong networks, and develop methods, prevention measures and
standards, which Europe is forced to use, since nothing similar exists for a network and combined
knowledge to design them according to european standards. This makes Europe extremely dependent and,
in some cases, the potential measures or standards cannot been used because the suggested solutions
are prohibited by European laws (e.g. use of biocides).
Therefore, it is important to initiate a new European MIC-network. Europe needs to combine the efforts as
experts in different fields and develop prevention measures according to the European rules, in close
cooperation with industry and plant operators and owners of critical infrastructure. This COST Action will
provide the necessary interaction and communication, knowledge sharing, training of personnel and of
researchers of different disciplines. This will bring Europe to a leading role in this process, bringing ideas on
an equal level with other nations, considering the values which are important for Europe and attitudes (e.g.environmental protection) and representing greater protection for people, property and the environment.
The main aim and objective of the Action is to , in the context of MIC-research/control, encourage a
fluent/synergistic collaboration/communication, closing the gap between materials scientists, engineers,
microbiologists, chemists and integrity managers to encourage sufficient interaction between academia and
industry. This Action will create a common MIC-Network, including the important stakeholders.
T2 - EuroCorr
CY - Online meeting
DA - 19.09.2021
KW - COST Action
KW - MIC
KW - Interdisciplinary
KW - Stakeholder
KW - Academia
PY - 2021
AN - OPUS4-53382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Towards sustainable solution-driven recycling of gypsum
N2 - Gypsum (CaSO₄·2H₂O) is a crucial mineral across sectors such as construction, agriculture, and biomedicine. Despite its potentially full recyclability, a shortage looms due to limited mining in Europe and decreasing production of flue gas desulfurization (FGD) gypsum, a byproduct of coal power plants. With current EU consumption at 24 MT/a (17 MT mined, 7 MT FGD), a deficit of 10-35 MT/a is projected by the 2030s as CaSO₄ becomes a critical raw material [1]. Meanwhile, substantial CaSO₄ waste is produced in various industries (e.g., phosphogypsum, red gypsum), but its recycling remains limited (10% in Germany, 5% in the EU) due to contamination and separation challenges.
This contribution introduces a sustainable, efficient wet-chemical method for converting gypsum to bassanite (CaSO₄·0.5H₂O), and thus recycling gypsum, under mild conditions (T < 100 °C) using reusable high-salinity aqueous solutions (brines with c[NaCl] > 4 M) [2]. The optimal conversion conditions (T > 80°C, c[NaCl] > 4 M) enable rapid (<5 min) and reversible transformation (Fig. 1). Upon cooling, gypsum re-forms, offering a temperature-dependent control over phase transition. Unlike conventional thermal dehydration (150-200 °C), this approach promotes the dissolution of gypsum, allowing contaminants to be separated via selective precipitation or adsorption. Additionally, the wet-chemical process facilitates the physical removal of impurities from gypsum matrices, making it advantageous for recycling gypsum waste from sources such as demolition or urban mining, where it is often mixed with other materials.
Our approach presents a sustainable pathway for recovering high-purity bassanite from contaminated gypsum waste, aligning with EU goals for resource conservation and waste reduction.
T2 - MaterialsWeek 2025
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - Gypsum
KW - Calcium sulfate
KW - Recycling
PY - 2025
AN - OPUS4-64677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Towards circular economy of gypsum
N2 - Gypsum (CaSO₄·2H₂O) is a crucial mineral across sectors such as construction, agriculture, and biomedicine. Despite its potentially full recyclability, a shortage looms due to limited mining in Europe and decreasing production of flue gas desulfurization (FGD) gypsum, a byproduct of coal power plants. With current EU consumption at 24 MT/a (17 MT mined, 7 MT FGD), a deficit of 10-35 MT/a is projected by the 2030s as CaSO₄ becomes a critical raw material [1]. Meanwhile, substantial CaSO₄ waste is produced in various industries (e.g., phosphogypsum, red gypsum), but its recycling remains limited (10% in Germany, 5% in the EU) due to contamination and separation challenges.
This talk introduces a sustainable, efficient wet-chemical method for converting gypsum to bassanite (CaSO₄·0.5H₂O), and thus recycling gypsum, under mild conditions (T < 100 °C) using reusable high-salinity aqueous solutions (brines with c[NaCl] > 4 M) [2]. The wet-chemical process facilitates the physical removal of impurities from gypsum matrices, making it advantageous for recycling gypsum waste from sources such as demolition or urban mining, where it is often mixed with other materials.
The approach presents a sustainable pathway for recovering high-purity bassanite from contaminated gypsum waste, aligning with EU goals for resource conservation and waste reduction.
T2 - GFZ Interface Geochemistry Seminars Spring 2025
CY - Potsdam, Germany
DA - 06.05.2025
KW - Calcium sulfate
KW - Circular economy
KW - Gypsum
PY - 2025
AN - OPUS4-64681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Historical Plaster Formulations and Their Influence on Crystallographic Microstructure
N2 - Historical plaster formulations offer valuable insights into advanced engineering in pre-modern cultures. This study examines two such gypsum-based recipes: Gach-e Koshteh from 14th-century Iran and Gesso Sottile from 15th-century Italy, both of which have unique characteristics and were essential for artistic and architectural decoration. By replicating these recipes in a laboratory setting, we demonstrate how traditional masters manipulated gypsum microstructure without additives to optimize the surface and mechanical properties of plaster for specific functional and artistic purposes.
The Koshteh recipe involves intensive kneading during plaster hydration, which retards setting and produces a platelet-like crystal morphology with alignment of the {010} faces, resulting in a hydrophilic surface ideal for water-based wall paintings. Sottile, in contrast, relies on slow recrystallization in excess water, generating loosely packed, needle-like crystals with reduced wettability—suitable for oil-based painting and gilding.
Using wide-angle X-ray scattering (WAXS), atomic force microscopy (AFM), and scanning electron microscopy (SEM), we reveal that the Koshteh recipe yields a denser, better-packed plaster with enhanced wettability, while the Sottile recipe forms larger, more loosely arranged crystals and a more hydrophobic surface. These findings underscore the ingenuity of historical materials engineering and offer valuable insights for modern conservation and sustainable restoration practices.
T2 - Geo4Göttingen 2025
CY - Göttingen, Germany
DA - 14.09.2025
KW - Plaster
KW - Gypsum
KW - Stucco
KW - Cultural heritage
PY - 2025
DO - https://doi.org/10.48380/4e5z-av91
AN - OPUS4-64685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Towards solution-driven recycling of gypsum
N2 - Gypsum (CaSO₄·2H₂O) is a crucial mineral across sectors such as construction, agriculture, and biomedicine. Despite its potentially full recyclability, a shortage looms due to limited mining in Europe and decreasing production of flue gas desulfurization (FGD) gypsum, a byproduct of coal power plants. With current EU consumption at 24 MT/a (17 MT mined, 7 MT FGD), a deficit of 10-35 MT/a is projected by the 2030s as CaSO₄ becomes a critical raw material [1]. Meanwhile, substantial CaSO₄ waste is produced in various industries (e.g., phosphogypsum, red gypsum), but its recycling remains limited (10% in Germany, 5% in the EU) due to contamination and separation challenges.
This contribution introduces a sustainable, efficient wet-chemical method for converting gypsum to bassanite (CaSO₄·0.5H₂O), and thus recycling gypsum, under mild conditions (T < 100 °C) using reusable high-salinity aqueous solutions (brines with c[NaCl] > 4 M) [2]. The optimal conversion conditions (T > 80°C, c[NaCl] > 4 M) enable rapid (<5 min) and reversible transformation. Upon cooling, gypsum re-forms, offering a temperature-dependent control over phase transition. Unlike conventional thermal dehydration (150-200 °C), this approach promotes the dissolution of gypsum, allowing contaminants to be separated via selective precipitation or adsorption. Additionally, the wet-chemical process facilitates the physical removal of impurities from gypsum matrices, making it advantageous for recycling gypsum waste from sources such as demolition or urban mining, where it is often mixed with other materials.
T2 - Geo4Göttingen 2025
CY - Göttingen, Germany
DA - 14.09.2025
KW - Calcium sulfate
KW - Gypsum
PY - 2025
DO - https://doi.org/10.48380/fhck-bv98
AN - OPUS4-64684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - extending the MOUSE in spirit: lifecycle of a GIXS experiment
N2 - We present the new grazing incidence mode at the MOUSE, which adapts and extends the MOUSE methodology developed for transmission X-ray scattering (Smales and Pauw, 2021). Our methodology begins and ends in discussion with our users and embraces automation for reproducible experiments including sample organisation, instrument configuration, documentation and data processing. This poster presents methodological innovations and challenges.
T2 - GISAXS 2025
CY - Hamburg, Germany
DA - 27.10.2025
KW - Grazing incidence
KW - X-ray scattering
KW - Experimental methodology
PY - 2025
AN - OPUS4-64694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bauer, L.J.
A1 - Wieder, Frank
A1 - Truong, V.
A1 - Förste, F.
A1 - Wagener, Y.
A1 - Jonas, A.
A1 - Praetz, S:
A1 - Schlesiger, C.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Kanngießer, B.
A1 - Zaslansky, P.
A1 - Mantouvalou, I.
T1 - Absorption Correction for 3D Elemental Distributions of Dental Composite Materials Using Laboratory Confocal Micro-X-ray Fluorescence Spectroscopy
N2 - Confocal micro-X-ray fluorescence (micro-XRF) spectroscopy facilitates three-dimensional (3D) elemental imaging of heterogeneous samples in the micrometer range. Laboratory setups using X-ray tube excitation render the method accessible for diverse research fields but interpretation of results and quantification remain challenging. The attenuation of X-rays in composites depends on the photon energy as well as on the composition and density of the material. For confocal micro-XRF, attenuation severely impacts elemental distribution information, as the signal from deeper layers is distorted by superficial layers. Absorption correction and quantification of fluorescence measurements in heterogeneous composite samples have so far not been reported. Here, an absorption correction approach for confocal micro-XRF combining density information from microcomputed tomography (micro-CT) data with laboratory X-ray absorption spectroscopy (XAS) and synchrotron transmission measurements is presented. The energy dependency of the probing volume is considered during the correction. The methodology is demonstrated on a model composite sample consisting of a bovine tooth with a clinically used restoration material.
KW - Micro X-ray fluorescence spectroscopy
KW - Dental composite materials
KW - Computed tomography
KW - Absorption correction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601630
DO - https://doi.org/10.1021/acs.analchem.4c00116
SN - 0003-2700
SN - 1520-6882
VL - 96
IS - 21
SP - 8441
EP - 8449
PB - American Chemical Society Publications
CY - Washington, DC
AN - OPUS4-60163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xin, L.
A1 - Mika, J.
A1 - Horbert, V.
A1 - Bischoff, S.
A1 - Schubert, H.
A1 - Borowski, J.
A1 - Maenz, S.
A1 - Huber, R.
A1 - Sachse, A.
A1 - Illerhaus, Bernhard
A1 - Kinne, R. W.
T1 - Systematic postoperative assessment of a minimally-invasive sheep model for the treatment of osteochondral defects
N2 - To assess the clinical course of a sheep stifle joint model for osteochondral (OC) defects, medial femoral condyles (MFC) were exposed without patella luxation using medial parapatellar skin (3–4 cm) and deep incisions (2–3 cm). Two defects (7 mm diameter; 10 mm depth; OC punch) were left empty or refilled with osteochondral autologous transplantation cylinders (OATS) and explanted after six weeks. Incision-to-suture time, anesthesia time, and postoperative wound or impairment scores were compared to those in sham-operated animals. Implant performance was assessed by X-ray, micro-computed tomography, histology, and immunohistology (collagens 1, 2; aggrecan). There were no surgery-related infections or patellar luxations. Operation, anesthesia, and time to complete stand were short (0.5, 1.4, and 1.5 h, respectively). The wound trauma score was low (0.4 of maximally 4; day 7). Empty-defect and OATS animals reached an impairment score of 0 significantly later than sham animals (7.4 and 4.0 days, respectively, versus 1.5 days). Empty defects showed incomplete healing and dedifferentiation/heterotopic differentiation; OATS-filled defects displayed advanced bone healing with remaining cartilage gaps and orthotopic expression of bone and cartilage markers. Minimally-invasive, medial parapatellar surgery of OC defects on the sheep MFC allows rapid and low-trauma recovery and appears well-suited for implant testing.
KW - Osteochondral stifle joint defect
KW - Sheep animal model
KW - Minimally-invasive parapatellar approach
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520180
DO - https://doi.org/10.3390/life10120332
SN - 2075-1729
VL - 10
IS - 12
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-52018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Soares, A.P.
A1 - Kupsch, Andreas
A1 - Baum, D.
A1 - Hesse, B.
A1 - Zaslansky, P.
T1 - Untersuchung der Integrität von glasfaserverstärkten Zahnstiften mittels Synchrotron-Röntgenrefraktion
N2 - Die Integrität der Verstärkungsfasern in Komposit-Zahnstiften ist entscheidend für die Biegefestigkeit und die langfristige Haftung am Zement in den Wurzelkanälen. Es wurde vermutet, dass die Integrität von glasfaserverstärkten Zahnstiften durch das Beschleifen während der zahnmedizinischen Behandlung beeinträchtigt wird. Eine Beschädigung der Fasern führt zu einer erheblichen strukturellen Schwächung über den gesamten Stiftdurchmesser. Glasfragmente, die durch den Kontakt mit dem Zahnbohrer entstehen, können sich vom Stift lösen und die Haftfähigkeit erheblich verringern. Mit Hilfe hochauflösender Synchrotron-Röntgen-Refraktions-Radiographie (SXRR) konnte das Ausmaß der Schäden zuverlässig identifiziert und charakterisiert werden.
Dazu wurden die Glasfaserstifte sowohl im Herstellungszustand als auch nach der Bearbeitung mit einem Diamantbohrer untersucht. Die Datensätze wurden zur Visualisierung und Quantifizierung der morphologischen Charakteristika intakter und durch das Beschleifen beschädigter Regionen analysiert. Sie zeigen Schäden im bearbeiteten Bereich (z. B. Brüche, Splitter und Risse) sowie herstellungsbedingte Inhomogenitäten der Fasern mit einer signifikanten Zunahme der inneren Oberflächen in Probenregionen, die durch das Beschleifen beschädigt wurden.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Röntgen-Refraktion
KW - Verbundwerkstoffe
KW - Zahnstifte
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549231
SP - 1
EP - 7
AN - OPUS4-54923
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bauer, L. J.
T1 - Integrated X-ray techniques for durable dental interzones
N2 - Nowadays, teeth are not directly extracted when tooth decay occurs. Whenever treatment of the affected tooth is possible, the carious region is replaced with a suitable filling. The filling material differs according to the position and size of the cavity. Since the restoration will remain in the tooth for many years, a well adhering and sealing interface between filling and healthy tooth tissue is needed. There is continuous development of new materials, but intensive studies of this complex interface between filling and healthy tooth are still lacking. Little is known about possible diffusion of elements from dental materials into healthy tooth tissue forming a socalled interzone with specific chemical and structural properties.
The combination of different analytical X-ray methods at synchrotron radiation facilities and in the laboratory enables an extensive structural and elemental investigation of such interzones. While X-ray fluorescence techniques and X-ray absorption spectroscopy yield elemental distributions and localized chemical speciation, X-ray diffraction, refraction and computed tomography add structural information to the full 3D analysis of model and real life tooth
samples. Within two DFG funded projects, we develop adapted methodologies and investigate
micro-chemical changes in interzones which we hypothesize may lead to sclerotic dentine.
T2 - Workshop of the Helmholtz association: MML - "From Matter to Materials and Life"
CY - Berlin, Germany
DA - 22.11.2021
KW - Dental materials
KW - X-ray refraction
KW - Computed tomography
KW - X-ray fluorescence
PY - 2021
AN - OPUS4-54097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sturm, R.
T1 - Refraktions-Radiographie - eine neue Methode zur Evaluation von Alterungsmechanismen wurzelkanalbehandelter Zähne
N2 - Ziel der Untersuchung: Evaluation der Eignung der Refraktions-Tomographie zur Analyse von Alterungserscheinungen innerhalb von adhäsiv verankerten Materialien vor und nach künstlicher Probenalterung.
Material und Methode: Vier humane mittlere Oberkieferfrontzähne wurden wurzelkanalbehandelt und ausgedehnte Klasse IV Defekte der Krone mit einer Aufbaufüllung aus dualhärtendem Komposit (Rebilda DC, VOCO) und einem Glasfaserstift (Rebilda Post, VOCO) restauriert. Alle Proben wurden feucht gelagert und in einer Synchrotron-Einrichtung (BAMline, BESSY II, HZB) mit einer Pixelgröße von 4,08 µm gescannt. Für diese Synchrotron-Refraktions-Tomographie (SXRCT) muss zunächst der Analysatorkristall (AK) zu einer Bragg-Reflexion (Beugung) angeregt werden, um eine SXRCT durchzuführen. Die SXRCT wird mit einer Transmissions-Tomographie (ohne AK) verrechnet. Darauf folgte eine künstliche Probenalterung mit 400.000 Kau- und 3.000 Thermozyklen (50N, 5-55°C). Anschließend wurden die Proben ein weiteres Mal gescannt. Die Datensätze beider SXRCT wurden mittels des „filtered back projection“ Algorithmus rekonstruiert, mit einer Bildanalyse-Software aufeinander registriert und ausgewertet. Hierdurch konnten die Veränderungen initialer Schädigungen analysiert werden.
Ergebnisse: Alle 4 Proben zeigten in den Scans Veränderungen des inneren Gefüges und an Grenzflächen nach Belastung. Es zeigten sich Ansammlungen von Wasser innerhalb eingeschlossener Hohlräume, subkritisches Risswachstum, Ausdehnung des Komposit und Quellung des Glasfaserstiftes um 0,4%. In den SXRCT Aufnahmen waren außerdem Dentintubuli, die bei Auflösungen von 4,08 µm sonst nicht deutlich sichtbar sind darstellbar. Dadurch konnte Eindringen von Wasser in die Tubuli im Anschluss an die Alterung belegt werden.
Zusammenfassung: SXRCT bietet die Möglichkeit, trotz einer vergleichbar geringen Auflösung, kleinste Strukturen und Veränderungen abzubilden. Dies ermöglicht unter anderem die detaillierte Analyse relativ großer Proben, wie eines vollständigen Zahnes in einem Scanvorgang.
T2 - 5. Gemeinschaftstagung Zahnerhaltung
CY - Munich, Germany
DA - 23.11.2023
KW - Röntgenrefraktion
KW - Computertomographie
KW - Zahnmedizin
PY - 2023
AN - OPUS4-59103
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - From the field to the lab and back: Evaluating the integrity of welded components using scaled experiments
N2 - This contribution addresses the question of how the behaviour of complex parts or components in industrial practice can be simulated using simple welding experiments in the laboratory. It is demonstrated how so-called mock-ups can be utilised for this purpose. In particular, a test rig specially designed for scaled welding experiments is shown. It allows mechanical restraints and stiffnesses to be simulated, as well as typical welding process parameters and post weld heat treatments. Selected examples show how solidification crack growth during welding of high-strength steels can be quantified, under which conditions stress relaxation cracks occur during the heat treatment of heat-resistant steels, and how the integrity of pressurised hydrogen pipelines can be assessed during repair welding.
T2 - 4th International Conference on Advanced Joining Processes 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - High strength steel
KW - Stress relief cracking
KW - Hydrogen
PY - 2025
AN - OPUS4-64505
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Comparability issues of test specimens in laser powder bed fusion - how to consider differences in thermal history of complex components and primitive test specimens
N2 - The capability to produce complexly and individually shaped metallic parts is one of the main advantages of the laser powder bed fusion (PBF-LB/M) process. However, the thermal history during additive manufacturing of complex components can differ significantly from the thermal history of geometrically primitive test specimens. This can result in divergent microstructures and resulting mechanical properties. It drastically limits the comparability of different built parts and requires expensive full component testing. Moreover, the thermal history as the spatiotemporal temperature distribution has been identified as a major cause for flaw formation. Therefore, it can be hypothesized that a similar thermal history between components and test specimens enhances their comparability. In this talk, the concept of representative test specimens is introduced, which enables the transfer of thermal histories from complex geometries to simple geometries, which can lead to better comparability of material properties.
T2 - 4th Asia-Pacific International Conference on Additive Manufacturing (APICAM)
CY - Melbourne, Australia
DA - 30.06.2025
KW - Additive Manufacturing
PY - 2025
AN - OPUS4-64527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Tim
A1 - Huber, Norbert
T1 - Designing microcompression experiments for nanoporous metals via computational plasticity
N2 - Micropillar compression testing is essential for understanding bulk metal plasticity at small scales and has emerged as a key technique for evaluating nanoporous metals like nanoporous gold (NPG). To support experimental design, we present a computational plasticity study on single crystal NPG micropillars, systematically examining four extrinsic factors: pillar height-to-diameter ratio, taper angle, friction coefficient, and misalignment angle. The study reveals that NPG exhibits similar trends to its bulk counterpart but is less prone to post-yield buckling in unstable crystal orientations. For optimal NPG pillar stability, an aspect ratio of is recommended and a moderate taper angle to prevent artificial stiffening and yielding. Even minimal friction enhances stability, while buckling is mainly governed by misalignment, requiring to also avoid underestimating the elastic modulus.
KW - Nanoporous gold
KW - Microcompression
KW - Plasticity
KW - Finite element method
KW - Micromechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645317
DO - https://doi.org/10.1016/j.matdes.2025.114550
SN - 0264-1275
VL - 258
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-64531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huber, Norbert
T1 - Perspectives and pitfalls in modeling of structure-property relationships using machine learning
N2 - Machine learning (ML) has been increasingly utilized to support microstructure characterization and predict mechanical properties. A successful ML model typically requires a comprehensive understanding of existing knowledge, expertise in translating this knowledge into meaningful input features, an effective ML architecture, and robust validation of the trained model. Despite the rapid growth in publications incorporating ML methods in recent years, there is limited literature specifically addressing nanoporous metals. The talk will give an overview on perspectives and pitfalls in modeling of structureproperty relationships using machine learning with focus on various challenges that arise from the specific nature of nanoporous metals including randomness of microstructure, image segmentation, lack of tomography data, feature engineering for property prediction, and implications for plasticity including anisotropic flow and arbitrary multiaxial loading on the lower scale of hierarchy. An outlook will be given on the perspectives of establishing a culture of open data, specifically towards curated data sets needed for training and validation of ML models. Potential use cases are the comparison of data from different sources, mining of more general relationships, and validation of models trained with computer generated data using experimental data.
T2 - 5th International Symposium on Nanoporous Materials by Alloy Corrosion
CY - Sendai, Japan
DA - 06.10.2025
KW - Nanoporous metals
KW - Machine learning
KW - Structure-properties relationship
KW - Materials design
PY - 2025
AN - OPUS4-64536
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirwald, Johannes
A1 - Khalighi, Sadaf
A1 - Varveri, Aikaterini
A1 - Hofko, Bernhard
A1 - Adwani, Dheeraj
A1 - Cannone-Falchetto, Augusto
A1 - Elwardany, Michael
A1 - Kleiziené, Rita
A1 - Konieczna, Katarzyna
A1 - Maliszewski, Maciej
A1 - Mouillet, Virginie
A1 - Nahar, Sayeda
A1 - Piérard, Nathalie
A1 - Pipintakos, Georgios
A1 - Porot, Laurent
A1 - Primerano, Kristina
A1 - Sharma, Aditi
A1 - Tavassoti, Pejoohan
A1 - Weigel, Sandra
A1 - Wetekam, Jens
A1 - Zhu, Jiqing
T1 - Evaluating the reproducibility and consistency of different sample preparation techniques used for ATR-FTIR spectroscopy from the RILEM 295-FBB TG1 round robin test
N2 - Attenuated Total Reflection Fourier Transform Infrared spectroscopy has become a popular spectroscopic technique in bituminous binder analysis. However, comparable results are not obtainable yet due to differences in devices, measurement routines, sample preparation procedures, and spectral evaluation. Thus, the Task Group 1 of the RILEM TC 295-FBB: “Fingerprinting bituminous binders using physicochemical analysis” focuses on bringing this method towards pre-standardization. This study evaluates the reproducibility and consistency from round robin test, where 21 participating laboratories performed six different preparation techniques on three different binders in an unaged, short-term, and long-term aged state. A total of 6461 spectra were recorded and evaluated for their mean, standard deviation and coefficient of variation (CV) in the spectral region between 1800 and 600 cm−1. The results show that the solid sample preparation methods provide excellent reproducibility, with a coefficient of variation below 2%. Only the solvent method showed a higher coefficient of variation at 7.18%. Outliers with a high CV were detected and categorized into two groups: one where only one of the four samples differed and the other where all 16 spectra showed slight scattering in the overall absorption. The consistency of the method is significantly influenced by the accuracy of sample preparation, which is crucial for minimizing differences in slope, baseline, and noise in the spectra. These findings show the excellent reproducibility of these sample preparation methods and will be further examined to establish universal indices for evaluating effects such as ageing, bringing the method closer towards standardization.
KW - Bitumen
KW - FTIR-Spektroskopie
KW - Reproducibility
KW - Round robin test
KW - Material handling
KW - preparation routine
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645386
DO - https://doi.org/10.1617/s11527-025-02755-1
SN - 1359-5997
VL - 58
IS - 8
SP - 1
EP - 21
PB - Springer Science and Business Media LLC
AN - OPUS4-64538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Yong
A1 - Hu, Kaixiong
A1 - Lilleodden, Erica T.
A1 - Huber, Norbert
T1 - Datasets for structural and mechanical properties of nanoporous networks from FIB reconstruction
N2 - This dataset paper presents a comprehensive archive of 3D tomographic reconstruction image files, volume mesh files for finite element simulations, and tabulated structural and mechanical properties data of nanoporous gold structures. The base material is nanoporous gold, fabricated using a dealloying process, with a solid fraction of approximately 0.30. The NPG samples with ligament sizes ranging from 20 nm to 400 nm were prepared by dealloying and by controlling the thermal annealing process. The original data consist of tomographic TIFF files acquired through Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) 3D reconstruction, as detailed in Philosophical Magazine 2016 96 (32-34), 3322-3335. At each ligament size, six sets of 3D tomographic images were obtained from different regions of the same sample to ensure representative data. New simulations and analyses were conducted based on the 3D image data. The resulting structural and mechanical property data of nanoporous gold are reported for the first time in this dataset paper. Volume meshing of the 3D reconstructed data was performed using Simpleware software. Structural parameters, including surface area, solid volume, and solid volume fraction of the nanoporous network, were extracted from the meshed volumes. Structural connectivity was assessed from the 3D microstructures. The meshed volumes were then used as input for finite element simulations performed in Abaqus to evaluate mechanical responses under uniaxial compression along all three principal axes respectively. From the resulting stress–strain curves, the Young’s modulus and yield strength of each structure were determined. Both elastic and plastic Poisson’s ratios were analyzed from true strain increments. This dataset includes the 3D tomographic images, corresponding volume mesh files, mechanical behavior data and tables summarizing the structural and mechanical properties. The archived data serve as a database for nanoporous network materials and can be reused for numerical simulations, additive manufacturing, and machine learning applications within the materials science community. All files are openly accessible via the TORE repository at https://doi.org/10.15480/882.15230
KW - Nanoporous gold
KW - Dealloying
KW - FIB/SEM tomography
KW - Finite element
KW - Volume mesh
KW - Young’s modulus
KW - Yield stress
KW - Poisson’s ratio
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645330
DO - https://doi.org/10.1016/j.dib.2025.112152
SN - 2352-3409
VL - 63
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-64533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Malefioudaki, Mariella
A1 - Misra, Archismita
A1 - Sbeity, Nadja
A1 - Zueco-Vincelle, Juan
A1 - Laguna-Bercero, Miguel A.
A1 - Koerdt, Andrea
A1 - Martín-Rapún, Rafael
A1 - Mitchell, Scott G.
T1 - Multifunctional polyoxomolybdate ionic liquid coatings for mitigating microbiologically influenced corrosion
N2 - Corrosion of metals and other materials in marine environments poses significant economic, operational, safety, and environmental challenges across the oil and gas industry, the renewable energy sector, and maritime infrastructure. Microbiologically influenced corrosion (MIC) accounts for a substantial portion of this corrosion, with sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) being key contributors. Conventional methods such as cathodic polarization have proven insufficient in mitigating the colonization of corrosive microbial communities in real marine environments, requiring the development of alternative, broad-spectrum antimicrobial strategies to prevent such biofilm formation. Recently, molybdate has emerged as a potential alternative to traditional biocides and nitrate. Our hypothesis is polyoxometalate-ionic liquids (POM-ILs), which exhibit antimicrobial and anticorrosion properties, could have a broader spectrum of antimicrobial activity than demonstrated until now and could be capable of shielding and protecting sensitive metal surfaces from the extreme acidic environments produced by MIC microorganisms. Here we show how two prototype polyoxomolybdate-based POM-ILs, [(CH3(CH2)6)4N]2[Mo6O19] and [(CH3(CH2)6)4N]4[Mo8O26], demonstrated antimicrobial activity at microgram per millilitre concentrations, prevented biofilm formation on metal surfaces, and provided resistance to corrosive acidic environments. Furthermore, impedance measurements were commensurate with electron microscopy studies showing that POM-IL-coated brass coupons withstood extremely corrosive environments. These proof-of-concept results demonstrate how multi-functional POM-IL coatings represent promising MIC mitigation solutions by providing a hydrophobic acid-resistant and biocidal protective layer that prevents biocolonisation and acidic corrosion by MIC microorganisms.
KW - Polyoxometalates
KW - Ionic liquid
KW - Microbiologically influenced corrosion
KW - Corrosion
KW - Heritage preservation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631951
DO - https://doi.org/10.1039/d5mh00373c
SN - 2051-6347
VL - 12
IS - 13
SP - 4648
EP - 4661
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-63195
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Li, Yong
A1 - Hu, Kaixiong
A1 - Lilleodden, Erica T.
A1 - Huber, Norbert
T1 - Datasets for structural and mechanical properties of nanoporous networks from FIB reconstruction
N2 - This dataset includes 3D tomographic reconstruction image files, volume mesh files for finite element simulations, and data on the structural and mechanical properties of nanoporous gold (NPG) structures. It serves as a supplement to a dataset paper, with the corresponding DOI provided in the “Related Identifiers” section. Detailed descriptions of the data, as well as the procedures for their preparation and curation, are presented in that paper.
The base material, nanoporous gold, was fabricated via a dealloying process and has a solid fraction of approximately 0.30. NPG samples with ligament sizes ranging from 20 nm to 400 nm were prepared through dealloying and subsequent thermal annealing. Tomographic TIFF files were obtained via Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) 3D reconstruction, with the procedure detailed in Philosophical Magazine (2016, 96(32–34), 3322–3335).
Based on the 3D image data, new simulations and analyses were performed. The resulting structural and mechanical property data of nanoporous gold are reported for the first time in the dataset paper and are archived here. This dataset provides a valuable database for the study of nanoporous network materials and can be reused for numerical simulations, additive manufacturing, and machine learning applications within the materials science community.
KW - Nanoporous gold
KW - Dealloying
KW - Coarsening
KW - FIB/SEM tomography
KW - Connectivity
KW - Finite element
KW - Volume mesh
KW - Young’s modulus
KW - Yield stress
KW - Poisson’s ratio
PY - 2025
DO - https://doi.org/10.15480/882.15230
PB - Technische Universität Hamburg Open Research
CY - Hamburg
AN - OPUS4-64534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erdmann, Maren
A1 - Kleinbub, Sherin
A1 - Wachtendorf, Volker
A1 - Schütter, Jan David
A1 - Niebergall, Ute
A1 - Böhning, Martin
A1 - Koerdt, Andrea
T1 - Photo-oxidation of PE-HD affecting polymer/fuel interaction and bacterial attachment
N2 - In the present study, a simple approach was used to investigate the effect of UV-exposure on two high density Polyethylene materials (PE-HD), commonly used for storage tanks, on fuel sorption behavior and colonization by microorganisms. The aim was to investigate whether the sorption behavior of the fuels (diesel/biodiesel) and the colonization by microorganisms, frequently occurring in the fuel, is affected and may lead to undesirable or safety-relevant material changes. We showed that the UV-irradiation leads to significant changes of the sorption behavior due to chemi-crystallization and crosslinking. The fuel Sorption is affected by the UV-induced formation of polar carbonyl and hydroxyl groups predominantly occurring at the surface. With respect to microbial colonization behavior for Bacillus subtilis and Pseudomonas aeruginosa, isolated from a contaminated diesel sample, differences of the initial adhesion could be shown depending on the initial type of polyethylene as well as on the degree of UV-induced degradation.
KW - High density polyethylene
KW - Bacterial attachment
KW - UV-irradiation
KW - Fuel sorption
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510001
DO - https://doi.org/10.1038/s41529-020-0122-1
VL - 4
IS - 1
SP - Article number: 18
PB - Nature Partner Journals
AN - OPUS4-51000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Digitale Werkzeuge für eine datengetriebene Qualitätssicherung
N2 - Der Vortrag stellt die in QI-Digital entwickelten und geplanten Werkzeuge einer digitalen Qualitätsinfrastruktur für die Additive Fertigung vor. Thematisiert werden u.a. die Verwaltungsschale und genormte Datenstrukturen im Kontext der Additiven Fertigung. Im Fokus steht hier die datengetriebene Qualitätssicherung.
T2 - Jahrestreffen der VDMA Arbeitsgemeinschaft Additive Fertigung
CY - Pegnitz, Germany
DA - 13.10.2025
KW - Additive Fertigung
KW - PBF-LB/M
KW - Digitalisierung
PY - 2025
AN - OPUS4-64402
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Datengetriebene Qualitätssicherung für den PBF-LB/M Prozess
N2 - Der Vortrag gibt einen Überblick über die aktuellen Aktivitäten im QI-Digital Use Case Additive Fertigung. Der Fokus liegt hier auf einer digitalen Qualitätssicherung.
T2 - Symposium „Additive Fertigung: Pulverbasiertes Schmelzen mittels Laserstrahl“
CY - Leipzig, Germany
DA - 14.08.2025
KW - Additive Fertigung
KW - PBF-LB/M
KW - Digitalisierung
PY - 2025
AN - OPUS4-64400
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
T1 - Herausforderungen beim Instandsetzungsschweißen von Altstahl – vom Werkstoffverhalten zur Schweißpraxis
N2 - Aus Gründen der Nachhaltigkeit und Wirtschaftlichkeit ist in der stahlverarbeitenden Industrie ein deutlicher Trend zum Bauen im Bestand zu beobachten, um kostenintensive Sperrungen oder Rückbaumaßnahmen zu vermeiden. Obwohl das Schweißen als effizientes und wirtschaftliches Fügeverfahren gilt, findet es im Zusammenhang mit Altstählen bislang nur begrenzt Anwendung. Stattdessen werden häufig Nieten- oder Schraubenverbindungen eingesetzt, die jedoch in vielen Fällen als unwirtschaftlich einzustufen sind.
Für Instandsetzungsmaßnahmen ist es häufig erforderlich, beschädigtes Bestandsmaterial durch moderne Stähle zu ersetzen oder Verbindungen zwischen Alt- und Neumaterialien herzustellen. Aufgrund der unterschiedlichen Herstellungsverfahren und Legierungskonzepte historischer Stähle ist jedoch nicht jeder Stahl aus dem 20. Jahrhundert ohne Weiteres schweißgeeignet. Daher ist zunächst eine systematische Prüfung der Schweißeignung erforderlich.
m Rahmen der vorliegenden Untersuchungen wurden verschiedene Altstähle hinsichtlich ihres Schweißverhaltens mittels Dilatometrie analysiert. Darüber hinaus wurden Schweißuntersuchungen an Mischverbindungen zwischen Altstahl und einem modernen Baustahl durchgeführt, um das Schweißverhalten und mögliche Gefügeveränderungen in der Übergangszone detailliert zu bewerten. Ziel war es, eine umfassende Datenbasis aus Schweiß-Zustands-Zeit-Diagrammen sowie Simulationen der Wärmeeinflusszone zu erstellen, um praxisrelevante Schweißuntersuchungen ableiten zu können. Diese Untersuchungen liefern wesentliche Erkenntnisse über das schweißmetallurgische Verhalten und die Schweißeignung der untersuchten Altstähle sowie deren Kombination mit modernen Werkstoffen.
Die gewonnenen Grundlagen bilden eine wichtige Basis für die Entwicklung innovativer schweißtechnischer Konzepte zur beanspruchungsgerechten Instandsetzung und Erhaltung bestehender Altstahl-Infrastrukturen in Deutschland.
T2 - Fortbildung für Schweißaufsichtspersonen Stahl- und Fahrzeugbau
CY - Berlin, Germany
DA - 15.10.2025
KW - Altstahl
KW - Mischverbindungen
KW - Instandsetzungsschweißen
KW - Dilatometrie
KW - Schweiß-ZTU-Schaubilder
PY - 2025
AN - OPUS4-64436
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
A1 - Lehmann Schlag, Jens
T1 - Korrosionsverhalten nichtrostender Stähle und Prüfverfahren
N2 - Der Vortrag behandelt die wesentlichen Einflussfaktoren auf die Korrosionsbeständigkeit rostfreier Stähle sowie gängige und neue Prüfmethoden zur Bewertung ihrer Widerstandsfähigkeit. Im Fokus stehen die Zusammenhänge zwischen Werkstoff, Verarbeitung, Medium und Konstruktion, insbesondere die Auswirkungen von Kalt- und Warmumformung, Schweißprozessen und Oberflächenbehandlungen wie Beizen oder Elektropolieren auf die Passivschichtbildung. Verschiedene Korrosionsarten – darunter Loch-, Spalt-, interkristalline und Spannungsrisskorrosion – werden hinsichtlich ihrer Entstehungsmechanismen und Prüfmethoden erläutert. Abschließend wird mit dem KorroPad®-Verfahren ein praxisnahes, schnelles Prüfverfahren vorgestellt, das die lokale Anfälligkeit von Oberflächen gegenüber Lochkorrosion sichtbar macht und zur Optimierung von Fertigungs- und Nachbearbeitungsprozessen dient.
T2 - Inhouse Seminar "Korrosionsverhalten nichtrostender Stähle"
CY - Ravensburg, Germany
DA - 15.10.2025
KW - Korrosion
KW - Nichtrostende Stähle
KW - KorroPad
KW - Passivität
KW - DIN 50024
PY - 2025
AN - OPUS4-64445
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann Schlag, Jens
A1 - Müller, Thoralf
T1 - Korrosionsschutzgerechte Werkstoffauswahl nichtrostender Stähle
N2 - Der Vortrag behandelt die systematische Auswahl nichtrostender Stähle unter Berücksichtigung mechanischer, chemischer und wirtschaftlicher Kriterien. Im Mittelpunkt steht das Zusammenspiel von Werkstoff, Medium und Umgebung, das die Korrosionsbeständigkeit als Systemeigenschaft bestimmt. Anhand von Kennzahlen wie Wirksumme, PRE(N) oder MARC wird die legierungsabhängige Beständigkeit gegenüber Loch- und Spaltkorrosion bewertet. Ergänzend werden Einflüsse wie Schwefelgehalt und Zerspanungsgüten auf das Korrosionsverhalten dargestellt. Der Vortrag zeigt praxisorientierte Hilfsmittel zur Werkstoffauswahl – darunter DECHEMA-Werkstofftabellen, ThyssenKrupp-Beständigkeitslisten und normative Vorgaben wie DIN EN 1993-1-4. Zudem werden typische Fehler bei der Werkstoffbestellung und -kennzeichnung erläutert und praxisnahe Empfehlungen gegeben, um korrosionsbedingte Schäden, etwa im Bauwesen oder bei Tunnelinstallationen, zu vermeiden.
T2 - Inhouse Seminar "Korrosionsverhalten nichtrostender Stähle"
CY - Ravensburg, Germany
DA - 15.10.2025
KW - Korrosion
KW - Nichtrostende Stähle
KW - Werkstoffauswahl
KW - Eurocode 3
KW - Korrosionsschutz
PY - 2025
AN - OPUS4-64446
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
A1 - Lehmann Schlag, Jens
T1 - Grundlagen der Korrosion
N2 - Der Vortrag behandelt die grundlegenden Reaktionen der Korrosion metallner Werkstoffe und erläutert das Prinzip der Passivität der nichtrostenden Stähle. Zusätzlich enthält der Vortrag beispielhafte Demoexperimente.
T2 - Inhouse Seminar "Korrosionsverhalten nichtrostender Stähle"
CY - Ravensburg, Germany
DA - 15.10.2025
KW - Korrosion
KW - Korrosionsschutz
KW - Nichtrostende Stähle
KW - Passivität
PY - 2025
AN - OPUS4-64443
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann Schlag, Jens
A1 - Müller, Thoralf
T1 - Glänzende Aussichten - Aus Schäden wird man klug
N2 - In diesem Beitrag werden Schadensbeispiele aus verschiedensten Branchenanwendungen nichtrostender Stähle gezeigt, die den Teilnehmern vor Augen führen sollen, an welchen Stellen Fehler zu Korrosionsschäden führen können.
T2 - Inhouse Seminar "Korrosionsverhalten nichtrostender Stähle"
CY - Ravensburg, Germany
DA - 15.10.2025
KW - Korrosion
KW - Nichtrostende Stähle
KW - KorroPad
KW - Metallografie
KW - Korrosionsschutz
PY - 2025
AN - OPUS4-64447
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
A1 - Lehmann Schlag, Jens
T1 - Systematik und Gefügearten nichtrostender Stähle
N2 - Der Vortrag erläutert die Bezeichnungssystematik nichtrostender Stahlsorten und stellt verschiedene Gefügearten und deren spezifische mechanisch-technologischen Eigenschaften gegenüber.
T2 - Inhouse Seminar "Korrosionsverhalten nichtrostender Stähle"
CY - Ravensburg, Germany
DA - 15.10.2025
KW - Korrosion
KW - Nichtrostende Stähle
KW - Gefügearten
KW - Stahlsorten
PY - 2025
AN - OPUS4-64444
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - Normungsaktivitäten in QI-Digital
N2 - Der Vortrag thematisiert die Normungsaktivitäten in QI-Digital. Insbesondere die entwickelte Datenstruktur in der ISO/ASTM 52970 und die Anknüpfungspunkte zur Verwaltungsschale. Die ISO TC 261 / JG 85 und ihr entsprechender Scope werden vorgestellt.
T2 - Sitzung des DIN NA-145-04-01 AA
CY - Darmstadt, Germany
DA - 01.04.2025
KW - Additive Fertigung
KW - PBF-LB/M
KW - Digitalisierung
PY - 2025
AN - OPUS4-64403
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epperlein, Martin
T1 - ISO TC 261 / JG 85 Projects
N2 - Dieser Vortrag fasst die laufenden Aktivitäten der ISO TC 261 JG 85 zusammen. Insbesondere die Gewinnung und Verarbeitung von PBF-LB/M Prozessdaten steht im Fokus.
T2 - ISO TC 261 / ASTM F.42 Meeting
CY - Manila, Philippines
DA - 22.09.2025
KW - Additive Fertigung
KW - PBF-LB/M
KW - Digitalisierung
PY - 2025
AN - OPUS4-64399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - Wasserstofflagerung in unterirdischen geologischen Formationen und potenzielle Risiken durch Mikroorganismen
N2 - Bei dem Vortrag werden die potentiellen mikrobiologischen Einflüsse im Falle der Lagerung von Wasserstofflagerung in unterirdischen geologischen Formationen vorgestellt, die Zusammenarbeit mit internen und auch externen Partnern. Der Fokus liegt dabei auf UGF; anaerobe Umgebungen, Sulfate reduzierenden Bakterien, methanogenen Archaea, weiterleitenden Systeme und die Kombination der Untersuchung abiotisch/biotische
T2 - VDI-Schadensanalyse (49)
CY - Würzburg, Germany
DA - 17.10.2023
KW - MIC
KW - Wasserstofflagerung
KW - Unterirdische Speicher
KW - Kontamination von H2
KW - H2-Abbau
KW - Mikroorganismen
KW - Biotische/abiotische Faktoren
PY - 2023
AN - OPUS4-58645
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - An, Biwen Annie
T1 - Standardization of MIC laboratory testing: with a special focus on corrosive methanogens
N2 - Microbiologically influenced corrosion (MIC) is a highly unpredictable process involving a complex group of microorganisms, including sulfate-reducing bacteria and methanogens. Standard laboratory MIC testing using static serum bottle enrichments is an easy but limited method, offering poor resolution on the biomineralization process of corrosion products. An example of this is the presumed corrosion product siderite by corrosive methanogens (Mi-MIC). Previous publications reported siderite was the sole corrosion product of M. maripaludis using metal coupons incubated under stationary conditions.
However, the formation of siderite is closely related to the surrounding environmental conditions, i.e. pH, CO2 concentration, flow and temperature. Thus, siderite as the sole corrosion product of Mi-MIC remain inconclusive and questionable. To study Mi-MIC effectively, a novel versatile multiport flow-column corrosion monitoring system (MFC) was developed. MFC allows sectional corrosion rate determination under flow conditions using different types of material, inoculum and packing material. MFC offers great flexibility, ease of operation and accurate corrosion measurements that can be combined with many other techniques. Using MFC, we studied multiple strains of methanogens and compared it with sulfate-reducing bacteria under neutral and low pH conditions. It was revealed by MFC that corrosive methanogens have equally high corrosion potential as sulfate-reducing bacteria. Additionally, siderite is not the dominant nor sole corrosion product of Mi-MIC. Thus, effective corrosion monitoring and establishing standard laboratory practices, i.e. incorporating MFC as part of regular testing process, will provide deeper understanding of MIC. This will allow further microbial electrophysiology understandings, contributing to effective mitigation strategy development.
T2 - EUROPEAN MIC NETWORK WEBINAR
CY - Online meeting
DA - 19.05.2020
KW - MIC
KW - Methanogen
KW - FIB/SEM
KW - Corrosion products
KW - Microbiologically influenced corrosion
KW - Flow Model
KW - Modelling
KW - Korrosion
PY - 2020
AN - OPUS4-51554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koerdt, Andrea
T1 - Mikrobiell beeinflusste Korrosion – die Testungsart entscheidet
N2 - In diesem kurzem Artikel wird die neue Testungsart druch Hi-Tension vorgestellt. Der Hauptfokus liegt dabei auf die Umweltsimulations-Säule, mit deren Hilfe die bisher bekannten Korrosionsraten von methanogenen Archaea signifikant erhöht wurden.
KW - Hi-Tension
KW - MIC
KW - Methanogene
KW - Umweltsimulation
PY - 2021
DO - https://doi.org/10.1007/s12268-021-1507-7
VL - 27
SP - 100
EP - 100
PB - BIOspektrum Springer
AN - OPUS4-52193
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yao, J.
A1 - Jiang, T.
A1 - Ji, Y.
A1 - An-Stepec, Biwen Annie
A1 - Koerdt, Andrea
A1 - Cai, Z.
A1 - Dong, C.
A1 - Ge, Y.
A1 - Qi, Z.
T1 - Water-Fueled Autocatalytic Bactericidal Pathway based on e-Fenton-Like Reactions Triggered by Galvanic Corrosion and Extracellular Electron Transfer
N2 - Water is generally considered to be an undesirable substance in fuel system, which may lead to microbial contamination. The antibacterial strategies that can turn water into things of value with high disinfection efficacy have been urgently needed for fuel system. Here, we reveal a water-fueled autocatalytic bactericidal pathway comprised by bi-metal micro-electrode system, which can spontaneously produce reactive oxygen species (mainly H2O2 and O2•–) by the electron Fenton-like reaction in water medium without external energy., The respiratory chain component of bacteria and the galvanic corrosion on the coated metals were two electron sources in the system. The specific model of Ag-Ru water-fueled autocatalytic (WFA) microelectrode particles presents extremely high disinfection efficiency (>99.9999%) in less than one hour for three aerobic bacteria (Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis) in LB media and high disinfection efficiency for the anaerobic bacteria (Desulfovibrio alaskensis) in Postgate E media without natural light irradiation. Overall, the novel WFA Ag-Ru antibacterial material explored in this study has a high potential for sterilizing applications in fuel system and this work provides the potential for the development of non-chemical and water-based antibacterial materials, such as WFA Ag-Ru antibacterial coating on stainless steel.
KW - Fenton-like reaction
KW - Reactive oxygen species
KW - Disinfection Fuel
KW - Silver
KW - Ruthenium
KW - MIC
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555186
DO - https://doi.org/10.1016/j.jhazmat.2022.129730
SN - 0304-3894
VL - 440
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
A1 - An, Biwen Annie
A1 - Deland, Eric
ED - Eibergen, N.
ED - Poulassichidis, T.
T1 - Novel Multiport Flow-Column Corrosion Monitoring System (MFC) Revealed High Corrosion Rates by Corrosive Methanogenic Archaea
N2 - MFC was used to study the corrosiveness of iron-utilizing methanogen, Methanobacterium IM1 under flow conditions. Comparing against electrical SRM, Desulfovibrio ferrophilus IS5, results showed under standard mesophilic conditions, average corrosion rates of Methanobacterium IM1 was double that of SRM. The highest corrosion rate of Methanobacterium IM1 reached up to 0.60 mm/yr under neutral conditions, and severe pitting was observed on the iron surface. Furthermore, the corrosion products of Methanobacterium IM1 were characterized with TOF-SIM, FIB-SEM and EDX, and preliminary results revealed FeCO3 is not the only corrosion product of Mi-MIC, as previously reported. Under low pH conditions, the maximum corrosion rate of Methanobacterium IM1 reached 1.57 mm/yr, which resulted in severed deformity of the iron specimen. Additional comparisons using different types of incubation material were conducted to standardize MFC MIC testing.
T2 - Corrosion 2021
CY - Online Meeting
DA - 19.04.2021
KW - MIC
KW - Microbiologically influenced corrosion
KW - Biocorrosion
KW - Hi-Tension
KW - Environmental condition
KW - Flow Model
KW - Modelling
KW - Korrosion
PY - 2021
UR - https://my.nace.org/PaperTrail/Authors/Submission.aspx?id=2b6387be-7390-ea11-813a-005056a95a7c
SP - Paper C2021-16303, 1
AN - OPUS4-52480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - Mikrobielle Zusammensetzung im Wassertank
N2 - Der Fachbereich 7.6 untersucht seit einiger Zeit an Auslagerungsständen auf dem Testgelände in Horstwalde Korrosion im maritimen Bereich. Im Moment läuft das System mit künstlichem Meerwasser und simuliert die Bewitterung von Metallproben unter angenäherten klimatischen Bedingungen ähnlich zum natürlichem Habitat. Im Laufe der Zeit konnte nicht intendierter mikrobieller bewuchs beobachtet werden. Es stellte sich die Frage, welche Mikroorganismen vorlagen und ob diese einen Einfluss auf die Korrosionsuntersuchungen haben könnte. Aus diesem Grund wurden 16S-rRNA Untersuchungen durchgeführt welche alle drei Domänen des Lebens widerspiegeln Bakterien, Archaea und Eukaryoten. Es konnte gezeigt werden, dass über 95% der vorliegenden Biomasse Grünalgen waren, die durch Licht Eintrag in den Container Photosynthese betrieben und dadurch an Biomasse zunahmen. Des weiteren konnten Bakterien detektiert werden, welche in der Regel halophilen und aeroben Habitaten zu finden sind. Allerdings wurden auch Sulfat reduzierende Bakterien (MIC) detektiert, wenn auch in einem geringen prozentualen Anteil. Es muss allerdings Berücksichtigt werden, dass die mikrobielle Zusammensetzung sich im Laufe der Zeit weiter ändern kann. Als Ursprung der Biomasse wird, das künstliche Sediment vermutet. Außerdem wäre es für zukünftige Experiment denkbar, das System mit echtem Sediment aus dem marinen Habitat anzuimpfen.
T2 - Dechema
CY - Online meeting
DA - 10.11.2021
KW - Mikroorganismen
KW - Mikrobielle Gemeinschaft
KW - Korrosion
KW - Simulation
PY - 2021
AN - OPUS4-54035
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knisz, J.
A1 - Eckert, R.
A1 - Gieg, L.
A1 - Koerdt, Andrea
A1 - Lee, J.
A1 - Silva, E.
A1 - Skovhus, T. L.
A1 - An Stepec, Biwen Annie
A1 - Wade, S. A.
T1 - Microbiologically Influenced Corrosion - More than just Microorganisms
N2 - Microbiologically influenced corrosion (MIC) is a phenomenon of increasing concern which affects various materials and sectors of society. MIC describes the effects, often negative, that a material can experience due to the presence of microorganisms. Unfortunately, although several research groups and industrial actors worldwide have already addressed MIC, discussions are fragmented, while information sharing and willingness to reach out to other disciplines is limited. A truly interdisciplinary approach, that would be logical for this material/biology/chemistry-related challenge, is rarely taken. In this review we highlight critical non-biological aspects of MIC that can sometimes be overlooked by microbiologists working on MIC but are highly relevant for an overall understanding of this phenomenon. Here, we identify gaps, methods and approaches to help solve MIC related challenges, with an emphasis on the MIC of metals. We also discuss the application of existing tools and approaches for managing MIC and propose ideas to promote an improved understanding of MIC. Furthermore, we highlight areas where the insights and expertise of microbiologists are needed to help progress this field.
KW - MIC
KW - Biodeterioration
KW - Biocorrosion
KW - Interdisciplinarity
KW - Multiple lines of evidence
PY - 2023
DO - https://doi.org/10.1093/femsre/fuad041
SN - 0168-6445
VL - 47
IS - 5
SP - 1
EP - 70
PB - FEMS Microbiology Reviews
AN - OPUS4-58066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andresen, Elina
T1 - Upconversion for security tags and future applications
N2 - NIR-excitable lanthanide nanocrystals (LnNC) show multi-color emission pattern composed of a multitude of narrow bands of varying intensity in the ultraviolet, visible, near-infrared, and short-wave infrared detectable with miniaturized optical instruments and simple color (RGB) cameras in complex environments. This makes these chemically inert luminescent materials ideal candidates for anticounterfeiting and authentication applications as well as for modules in optical sensors in which the LnNCs can be used as nanolamps in combination with analyte-sensitive fluorophores or the temperature sensitivity of defined emission bands can be utilized.
Therefore, we are building up and exploring a platform of LnNC with application-specifically tuned size, composition, and surface chemistry.
T2 - SHIFT 2022
CY - La Laguna, Tenerife, Spain
DA - 10.10.2022
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
PY - 2022
AN - OPUS4-56229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Tavernaro, Isabella
A1 - Genger, C.
A1 - Welker, P.
A1 - Huebner, Oskar
A1 - Resch-Genger, Ute
T1 - Multicolor Polystyrene Nanosensors for the Monitoring of Acidic, Neutral, and Basic pH Values and Cellular Uptake Studies
N2 - A first tricolor fluorescent pH nanosensor is presented, which was rationally designed from biocompatible carboxylated polystyrene nanoparticles and two analyte-responsive molecular fluorophores. Its fabrication involved particle staining with a blue-red-emissive dyad, consisting of a rhodamine moiety responsive to acidic pH values and a pH-inert quinoline fluorophore, followed by the covalent attachment of a fluorescein dye to the particle surface that signals neutral and basic pH values with a green fluorescence. These sensor particles change their fluorescence from blue to red and green, depending on the pH and excitation wavelength, and enable ratiometric pH measurements in the pH range of 3.0−9.0. The localization of the different sensor dyes in the particle core and at the particle surface was confirmed with fluorescence microscopy utilizing analogously prepared polystyrene microparticles. To show the application potential of these polystyrene-based multicolor sensor particles, fluorescence microscopy studies with a human A549 cell line were performed, which revealed the cellular uptake of the pH nanosensor and the differently colored emissions in different cell organelles, that is, compartments of the endosomal-lysosomal pathway. Our results demonstrate the underexplored potential of biocompatible polystyrene particles for multicolor and multianalyte sensing and bioimaging utilizing hydrophobic and/or hydrophilic stimuli-responsive luminophores.
KW - Microparticle
KW - Fluorescence
KW - Sensor
KW - pH
KW - Quantum yield
KW - Multiplexing
KW - Imaging
KW - Cell
KW - Quality assurance
KW - Nano
KW - Polymer
KW - Bioimaging
KW - Particle
KW - Application
PY - 2022
DO - https://doi.org/10.1021/acs.analchem.2c00944
VL - 94
IS - 27
SP - 9656
EP - 9664
PB - ACS
AN - OPUS4-55365
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Daly, H.C
A1 - Matikonda, S.S
A1 - Steffens, H.C
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Ivanic, J.
A1 - Schermann, M.J
T1 - Daly_Photochem Photobiol 2021_Ketone Incorporation Extends the Emission Properties of the Xanthene Scaffold
N2 - Imaging in the shortwave-infrared region (SWIR, λ = 1000–2500 nm) has the potential to enable deep tissue imaging with high resolution. Critical to the development of these Methods is the identification of low molecular weight, biologically compatible fluorescent probes that emit beyond 1000 nm.
Exchanging the bridging oxygen atom on the xanthene scaffold (C10’ position) with electron withdrawing groups has been shown to lead to significant redshifts in absorbance and emission. Guided by quantum chemistry computational modeling studies, we investigated the installation of a Ketone bridge at the C10’ position. This simple modification extends the absorbance maxima to 860 nm and the emission beyond 1000 nm, albeit with reduced photon output. Overall, These studies demonstrate that broadly applied xanthene dyes can be extended into the SWIR range.
KW - Flourescence
KW - Optical probe
KW - Dye
KW - Photophysics
KW - Quantum yield
KW - Mechanism
KW - NIR
KW - SWIR
KW - Imaging
KW - Reliability
KW - Method
KW - Quality assurance
PY - 2021
DO - https://doi.org/10.1111/php.13544
SN - 1751-1097
VL - 98
IS - 2
SP - 325
EP - 333
PB - Wiley Online Library
AN - OPUS4-54080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Würth, Christian
A1 - Frenzel, Florian
A1 - Weigert, Florian
A1 - Andresen, Elina
A1 - Grauel, Bettina
A1 - Wegner, Karl David
T1 - Semiconductor (SCNC) & Upconversion Nanocrystals (UCNC) – Optical Properties, Applications & Challenges
N2 - Inorganic nanocrystals with linear and nonlinear luminescence in the ultraviolet, visible, near infrared and shortwave infrared like semiconductor quantum dots and spectrally shifting lanthanide-based nanophosphors have meanwhile found applications in the life and material sciences ranging from optical reporters for bioimaging and sensing over security barcodes to solid state lighting and photovoltaics. These nanomaterials commonly have increasingly sophisticated core/shell particle architectures with shells of different chemical composition and thickness to minimize radiationless deactivation at the particle surface that is usually the main energy loss mechanism [1]. For lanthanide-based spectral shifters, particularly for very small nanoparticles, also surface coatings are needed which protect near-surface lanthanide ions from luminescence quenching by high energy vibrators like O-H groups and prevent the disintegration of these nanoparticles under high dilution conditions. [2,3,4]. The identification of optimum particle structures requires quantitative spectroscopic studies focusing on the key performance parameter photoluminescence quantum yield [5,6], ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods [7], Moreover, in the case of upconversion nanoparticles with a multi-photonic and hence, excitation power density (P)-dependent luminescence, quantitative luminescence studies over a broad P range are required to identify particle architectures that are best suited for applications in fluorescence assays up to fluorescence microscopy. Here, we present methods to quantify the photoluminescence of these different types of emitters in the vis/NIR/SWIR and as function of Pand demonstrate the importance of such measurements for a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments.
T2 - 27th Annual Meeting of the Slovenian Chemical Society
CY - Portoroz-Portorose, Slovenia
DA - 21.09.2021
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Surface chemistry
KW - Single particle
KW - Brightness
KW - NIR
KW - Synthesis
KW - Semiconductur
KW - Quantum dot
KW - Nanocrystal
KW - SWIR
PY - 2021
AN - OPUS4-53723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
T1 - Tumore abbilden, Biomarker nachweisen, Messungen standardisieren
N2 - Zu den am häufigsten eingesetzten Analysemethoden in den Lebens- und Materialwissenschaften gehören Lumineszenzmethoden. Sie nutzen die Emission von Licht nach Absorption von Energie, um Signale zu erzeugen, und umfassen spektroskopische und mikroskopische Messungen.
KW - Quality assurance
KW - Sensor
KW - Imaging
KW - Reference material
KW - Nano
KW - Particle
KW - Nanomaterial
KW - Upconversion
KW - Nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Excitation
KW - Power density
KW - Single particle
KW - Brightness
KW - NIR
PY - 2021
SP - 75
EP - 77
PB - GDCH
AN - OPUS4-53526
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Engineered Nanomaterials- Novel Approaches for Risk Assessment and Safe-by-Design
N2 - The overall interest in nanotoxicity, triggered by the increasing use of nanomaterials in the material and life sciences, and the synthesis of an ever increasing number of new functional nanoparticles calls not only for standardized test procedures1,2 and for efficient approaches to screen the potential genotoxicity of these materials, but also for standardized and validated methods for surface analysis.
4,5 The analysis and quantification of surface chemistry is hence in the focus of an increasing number of standardization organizations and interlaboratory comparisons with different analytical methods are being done.5 For the monitoring of nanomaterial synthesis and the fast assessment of the number of functional groups such as carboxyl and amino functionalities, which are very commonly used functionalities in the life sciences, simple and validated methods are needed that can be performed with common laboratory instrumentation. 5,6 Here we provide a brief overview of the ongoing research in division Biophotonics employing quantitative NMR (qNMR), conductometry, and colorimetric and fluorometric optical assays for the determination of the total and the accessible number of carboxyl and amino groups on differently sized polymer and silica nano- and microparticles.5-7
T2 - Workshop NanoRiskSD project
CY - Berlin, Germany
DA - 09.06.2022
KW - Nanoparticle
KW - Surface analysis
KW - Standardization
KW - Quality assurance
KW - Validation
KW - qNMR
KW - Silica
KW - Polymer
KW - Fluorescence
KW - Assay
KW - Conductometry
KW - Method comparison
KW - Analytical sciences
PY - 2022
AN - OPUS4-54999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauli, Jutta
A1 - Würth, Christian
A1 - Güttler, Arne
A1 - Resch-Genger, Ute
T1 - Reliable Determination of the Signal-Relevant Spectroscopic Key Characteristics of Luminescent Reporters and Optical Probes for Imaging in the vis/NIR/SWIR
N2 - Introduction. Comparing different emitter classes and rationally designing the next generation of molecular and nanoscale probes for bioimaging applications require accurate and quantitative methods for the measurement of the key parameter photoluminescence quantum yield f.1 f equals the number of emitted per number of absorbed photons. This is particularly relevant for increasingly used fluorescence imaging in the short wave-infrared region (SWIR) ≥ 900 nm providing deeper penetration depths, a better image resolution, and an improved signal-to-noise or tumor-to-background ratio.2, 3 However, spectroscopic measurements in the SWIR are more challenging and require specific calibrations and standards.
T2 - EMIM 2021
CY - Göttingen, Germany
DA - 24.08.2021
KW - Fluorescence
KW - Optical probe
KW - Dye
KW - Photophysics
KW - Quantum yield
KW - Mechanism
KW - NIR
KW - SWIR
KW - Imaging
KW - Reference material
KW - Reliability
KW - Nano
KW - Particle
KW - Method
KW - Quality assurance
PY - 2021
AN - OPUS4-53233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Applications of photoluminescence lifetime measurements in the life and material sciences
N2 - Bioanalytical, diagnostic, and security applications require the fast and sensitive determination of a steadily increasing number of analytes or events in parallel in a broad variety of detection formats and increased sensitivities. This – flanked by recent technical advancements and the availability of simple to use, commercial time-resolved photoluminescence measuring devices at reasonable costs - calls for the exploitation of the species- and environment-specific photoluminescence parameter luminescence lifetime. In this context, time-resolved photoluminescence measurements of different classes of molecular and nanocrystalline emitter and luminescent particles in different time windows are presented and examples for applications such as lifetime multiplexing and barcoding in conjunction with fluorescence lifetime imaging microscopy (FLIM) and flow cytometry are given.
T2 - Eingeladener Vortrag bei dem Workshop von Picoquant „Time-resolved fluorescence“
CY - Berlin, Germany
DA - 17.11.2022
KW - Dye
KW - Quantum dot
KW - Upconversion nanocrystal
KW - Luminescence
KW - Quantitative spectroscopy
KW - Photophysics
KW - Quality assurance
KW - Nano
KW - Particle
KW - Quantum yield
KW - Lifetime
KW - Standard
KW - Reference material
PY - 2022
AN - OPUS4-57048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Design and Quantitative Characterization of Functional Molecular Chromophores and Nanomaterials with UV/vis/NIR/IR Emission – An Overview of Research Activities in Division Biophotonics
N2 - In the focus of division Biophotonics are the design, preparation, analytical and spectroscopic characterization, and application of molecular and nanoscale
functional materials, particularly materials with a photoluminescence in the visible, near infrared (NIR) and short-wave infrared (SWIR). This includes optical reporters for bioimaging and sensing, security and authentication barcodes, and materials for solid state lighting, energy conversion, and photovoltaics. For the identification of optimum particle structures quantitative spectroscopic studies are performed under application-relevant conditions, focusing on the key performance parameter photoluminescence quantum yield. In addition, simple, cost-efficient, and standardizable strategies for quantifying functional groups on the surface of nano- and microparticles are developed, here with a focus on optical assays and electrochemical titration methods, cross-validated by more advanced methods such as quantitative NMR. In addition, reference materials and reference products are developed for optical methods, particularly luminescence techniques, and for analytical methods utilized for the characterization of nanomaterials.
T2 - Projekttreffen Nile-Chrome 2.0
CY - Mainz, Germany
DA - 11.12.2023
KW - Fluorescence
KW - Quantum yield
KW - Optical spectroscopy
KW - Reference material
KW - Reference data
KW - Quality assurance
KW - Dye
KW - Reference product
KW - NIR
KW - SWIR
KW - Nano
KW - Particle
KW - Silica
KW - Polymer
KW - Surface group analysis
KW - Sensor molecules
PY - 2023
AN - OPUS4-59123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Design of Fluorescent, Amorphous Silica-NPs and their Versatile Use in Sensing Applications
N2 - Surface functionalized silica nanoparticles (SiO2-NP) gained great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. They are highly stable, are easily produced and modified on a large scale at low cost and can be labeled or stained with a multitude of sensor dyes. These dye modified particle conjugates have several advantages as compared to conventional molecular probes like enhanced brightness, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, stained nanoparticles can enable the use of hydrophobic dyes in aqueous environments.
Here we present our work on multicolored sensors for the measurement of pH, oxygen and saccharides utilizing amorphous SiO2 NPs.
T2 - Focus Area Day Analytical Sciences 2023
CY - Berlin, Germany
DA - 20.04.2023
KW - Amorphous silica particles
KW - Particle Synthesis
KW - Nano
KW - Ratiometric Sensors
KW - Fluorescence
KW - pH probe
KW - Dye
PY - 2023
AN - OPUS4-59151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Measuring the Upconversion Luminescence of Ensemble and Single Particle Lanthanide-Based Upconversion Nanocrystals
N2 - Lanthanide-based upconversion nanoparticles (UCNPs) like hexagonal 𝛽-NaYF4 UCNPs doped with Yb3+ and Er3+, which efficiently convert 976 nm light to ultraviolet, visible, and near infrared photons, offer new strategies for luminescence-based sensing, barcoding, and Imaging. Their upconversion (UC) luminescence (UCL) features like UCL intensity, quantum yield, relative spectral distribution / UCL luminescence color, and luminescence decay kinetics are, however, strongly influenced by particle size, dopant ion concentration, particle architecture, surface chemistry including presence and thickness of surface passivation and shielding shells, microenvironment/presence of quenchers with high energy vibrations, and excitation power density (P).
We present here a comprehensive study of the influence of excitation power density on the UCL features of different types of UCNPs, focusing on Yb3+ and Er3+ co-doped NaYF4 core-only and core-shell nanostructures with different sizes and doping ion concentration, which underlines the importance of P-dependent optimum dopant concentrations for UCNP performance and the potential of P-tuning of UCL.
T2 - Materials Challenges in Alternative & Renewable Energy 2021 (MCARE 2021)
CY - Online meeting
DA - 19.07.2021
KW - Fluorescence
KW - Lifetime
KW - Method
KW - Stability
KW - Coating
KW - Surface chemistry
KW - Lanthanide
KW - Upconversion
KW - Nano
KW - Particle
KW - Single particle spectroscopy
KW - Quantum yield
KW - Microscopy
KW - Photophysics
PY - 2021
AN - OPUS4-53111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - Advancing Short-Wave Infrared (SWIR) Emission
N2 - There is a growing interest in the exploitation of the short-wave infrared (SWIR), which refers to the wavelength band of light between 900 nm and 2500 nm. Luminophores that emit in the SWIR are used in various areas of telecommunications, photovoltaics, security systems (night vision), and in biomedicine. In particular for biomedical applications, the SWIR range is highly promising because light scattering, absorption, and autofluorescence of tissue and biological compounds are strongly reduced compared to the visible (400–700 nm) and NIR (~700–900 nm). The benefits of SWIR-emissive QDs have been demonstrated for a variety of applications, such as in thermal sensing, as photoelectrochemical biosensor, in in vivo vascular imaging, and for fluorescence-guided surgery.[1]
Full exploitation of SWIR photoluminescence (PL) imaging and sensing is currently hampered by i.) a lack of suitable advanced nanomaterials with a high PL quantum yield (PL QY) and a high brightness, that can be used safely in vivo and ii.) a lack of quantitative and reliable data on the optical properties of many SWIR emitters. Promising nanomaterials for the SWIR are heavy metal-free Ag2S quantum dots (QDs).
Aiming for the development of SWIR advanced nanomaterials with optimum performance, we have dived deeper into the photophysical processes occurring in these nanomaterials, thereby exploring in depth how the environment such as temperature, surface ligand composition, and the incorporation of transition metals influence the optical properties Ag2S QDs. We observed a strong enhancement of the SWIR emission of upon addition of metal ions such as Zn2+, yielding PL quantum yields of about 10% and thus making them highly suitable for non-invasive deep imaging of vascular networks and 3D fluid flow mapping.
T2 - Anakon 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Quantum dots
KW - Nano
KW - Particle
KW - SWIR
KW - Fluorescence
KW - Temperature
KW - Ag2S
KW - Quality assuarance
KW - Ligand
KW - Sensor
PY - 2025
AN - OPUS4-62769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andresen, Elina
T1 - Lanthanide based multi element nanoparticles: a versatile platform for surface chemistry analysis and potential reference materials
N2 - The use of engineered nanoparticles of different size, shape, and composition is continuously increasing in the life and materials sciences. This calls for methods and reference materials enabling the reliable and accurate determination of nanoparticle size, particle size distribution, shape, number concentration, degree of aggregation and agglomeration in different environments as well as for nanoparticle dispersibility and stability.
We are currently building up and exploring a platform of lanthanide-based nanocrystals (LnNCs) with application-specifically tuned size, shape, composition, architecture, optical properties, and surface chemistry for emerging applications in life sciences. As a prerequisite for the broad applicability of these nanomaterials, we assess simple, robust, and easily upscaleable synthesis protocols for LnNCs with defined morphologies and tunable optical properties, and the short-term and long-term stability of LnNCs with selected surface coatings in aqueous environments under different application-relevant conditions.
T2 - Anakon 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Nano
KW - Particle
KW - Method
KW - Lanthanide
KW - Synthesis
KW - Upconversion
KW - Ligand
KW - Quality assurance
KW - Particle number concentration
KW - Reference material
KW - Surface chemistry
PY - 2025
AN - OPUS4-62768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - How to Quantify the Total and Accessible Number of Functional Groups and Ligands on Nanomaterials Using a Multimodal Approach – A Bilateral Comparison
N2 - Surface-functionalized organic and inorganic engineered nanomaterials (NM) have gained increasing interest in various fields of application such as nanomedicine, bioimaging and sensing, or as additives in food and consumer products. The performance and safe use of these NM in such applications depend not only on their composition, primary particle size, and morphology, but also on surface chemistry, which controls surface charge, colloidal stability, biocompatibility, and toxicity.[1] NM surface chemistry is mainly determined by the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules. Thus, methods for FG quantification are not only important tools for the control of NM production processes, but can also foster the sustainable development of functional and safe(r) NM. In addition, this need underlines the importance of validated and standardized analytical methods that provide accurate information on application-relevant physicochemical properties with known uncertainties, flanked by suitable quality control samples and reference materials. Aiming at the development of simple, versatile, and multimodal tools for the quantification of common bioanalytically relevant FG, we investigated and compared various analytical methods commonly used for FG quantification.[2,3] The potential of multimodal approaches for FG quantification was recently demonstrated in a bilateral comparison of the surface analysis of commercially available aminated silica nanoparticles (SiO2-NP).[3] These results demonstrate not only an influence of the size and synthesis methods on the number of FG but also on NM performance. This concept is currently explored in a second bilateral comparison of quantitative nuclear magnetic resonance (qNMR) measurements and optical assays for differently sized commercial and in-house synthesized SiO2-NP with varying amounts of amine functionalities, utilizing further optimized protocols for sample preparation, qNMR measurements, and data evaluation. This strategy can contribute to establishing multi-method characterization strategies for NMs and can provide a more detailed picture of structure-properties relationships for different types of functional NM.
T2 - E-MRS Spring Meeting 2024 & ALTECH 2024
CY - Strasbourg, France
DA - 27.05.2024
KW - Quantification
KW - Nano
KW - Particle
KW - Quality assurance
KW - Interlaboratory comparison
KW - Method
KW - Uncertainty
KW - Reference material
KW - Sensors
KW - Synthesis
KW - Silica
KW - Surface analysis
PY - 2024
AN - OPUS4-62161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhao, J.
A1 - Hu, Y.
A1 - wei Lin, S.
A1 - Resch-Genger, Ute
A1 - Zhang, R.
A1 - Wen, J.
A1 - Kong, X.
A1 - Qin, A.
A1 - Ou, J.
T1 - Enhanced luminescence intensity of near-infraredsensitized sensitized upconversion nanoparticles via Ca²+ doping for a nitric oxide release platform
N2 - Light-induced NO release based on exogenous NO donors has attracted substantial attention in clinical applications; the induction light source usually converts near-infrared light to blue or ultraviolet light.
However, the low efficiency of near-infrared light-assisted chemical light energy conversion remains a challenge, especially for NaYF4:Yb3+/Tm3+ photoconverting near-infrared light to ultraviolet (UV) and blue light. In this paper, a luminescence-enhanced strategy is reported by doping Ca2+ into NaYF4:Yb3+/Tm3+ and coating it with NaGdF4 through a two-step solvothermal method. Then, UCNPs modified with methyl-b-cyclodextrin (M-b-CD) are loaded on a ruthenium nitrosyl complex [(3)Ru(NO)(Cl)] as nitric oxide release-molecules (NORMs). X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) data demonstrated that Ca2+ was successfully doped into NaYF4:Yb3+/Tm3+ nanoparticles as the core, and a pure hexagonal phase, NaYF4, was obtained from the doping of Ca2+. TEM revealed that the crystallinity was significantly improved after Ca2+ doping, and the core–shell structure was successfully synthesized, with NaGdF4 directionally grown on the NaYF4:Ca/Yb/Tm core. Fluorescence tests showed that, especially in the ultraviolet and blue light excitation wavelength regions, the UC emission intensity of the Ca-doped NaYF4:Yb3+/Tm3+@NaGdF4 core–shell UCNPs increased by 302.95 times vs. NaYF4:Yb3+/Tm3+ UCNPs. Finally, the release of NO was tested by the Griess method. Under 980 nm irradiation, the cell viability distinctly decreased with increasing UCNPs@M-b-CD-NORMs concentration. This study Shows that NORM release of NO is triggered by enhanced up-converted UV and blue light, which can be used for the development of UV photo-sensitive drugs.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Surface chemistry
KW - Single particle
KW - Brightness
KW - NIR
KW - PDT
PY - 2020
DO - https://doi.org/10.1039/d0tb00088d
VL - 8
IS - 30
SP - 6481
EP - 6489
PB - Journal of Materials Chemistry B
AN - OPUS4-51262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Typical Measurements in Optical Spectroscopy – Absorption Spectroscopy or Photometry
N2 - The basics of absorption spectroscopy (termed also photometry) will be presented with focus on transparent solutions of different molecular and nanocrystalline absorbers and the ultraviolet (UV), visible (vis), and near-infrared (NIR) spectral region. Thereby, also typical sources of uncertainty will be addressed. Subsequently, several examples for typical applications of absorption measurements in the life and material sciences will be briefly shown ranging from aggregation studies and dye labeling densities of biomolecules (dye-to-biomolecule ratios) over optical assays for thiol and protein quantification to the optical determination of the size of semiconductor nanocrystals using size curves.
T2 - pHD Seminar
CY - Online meeting
DA - 03.11.2020
KW - Quantification
KW - Absorption
KW - Dye
KW - Nano particle
KW - Method
KW - Measurement uncertainty
KW - Linearity
PY - 2020
AN - OPUS4-51621
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, F.
A1 - Rietsch, P.
A1 - Sinha, S.
A1 - Krappe, A.
A1 - Joswig, J.-O.
A1 - Götze, J. P.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
A1 - Eigler, S.
A1 - Paulus, B.
T1 - Fluorescence Quenching in J‑Aggregates through the Formation of Unusual Metastable Dimers
N2 - Molecular aggregation alters the optical properties of a system as fluorescence may be activated or quenched. This is usually described within the well-established framework of H- and J-aggregates. While H-aggregates show nonfluorescent blueshifted absorption bands with respect to the isolated monomer, Jaggregates are fluorescent displaying a redshifted peak. In this publication, we employ a combined approach of experiment and theory to study the complex aggregation features and photophysical properties of diaminodicyanoquinone derivatives, which show unusual and puzzling nonfluorescent redshifted Absorption bands upon aggregation. Our theoretical analysis demonstrates that stable aggregates do not account for the experimental observations.
Instead, we propose an unprecedented mechanism involving metastable dimeric species formed from stable dimers to generate nonfluorescent J-aggregates. These results represent a novel kind of aggregation-induced optical effect and may have Broad implications for the photophysics of dye aggregates.
KW - Fluorescence
KW - Llifetime
KW - Dye
KW - Quantum yield
KW - Label
KW - Reporter
KW - Aggregation
KW - Monomer
KW - Heory
KW - Mechanism
KW - photophysics
PY - 2021
DO - https://doi.org/10.1021/acs.jpcb.1c01600
SN - 1520-5207
VL - 125
IS - 17
SP - 4438
EP - 4446
PB - ACS Publikations
AN - OPUS4-52619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, Florian
A1 - Würth, Christian
A1 - Dukhno, O.
A1 - Przybilla, F.
A1 - Wiesholler, L. M.
A1 - Muhr, V.
A1 - Horsch, T.
A1 - Mély, Y.
A1 - Resch-Genger, Ute
T1 - Multiband emission from single β-NaYF4(Yb,Er) nanoparticles at high excitation power densities and comparison to ensemble studies
N2 - Ensemble and single particle studies of the excitation power density (P)-dependent upconversion luminescence (UCL) of core and core–shell β-NaYF4:Yb,Er upconversion nanoparticles (UCNPs) doped with 20% Yb3+ and 1% or 3% Er3+ performed over a P regime of 6 orders of magnitude reveal an increasing contribution of the emission from high energy Er3+ levels at P > 1 kW/cm2.
This changes the overall emission color from initially green over yellow to white. While initially the green and with increasing P the red emission dominate in ensemble measurements at P < 1 kW/cm2, the increasing population of higher Er3+ energy levels by multiphotonic processes at higher P in single particle studies results in a multitude of emission bands in the ultraviolet/visible/near infrared (UV/vis/NIR) accompanied by a decreased contribution of the red luminescence. Based upon a thorough analysis of the P-dependence of UCL, the emission bands activated at high P were grouped and assigned to 2–3, 3–4, and 4 photonic processes involving energy transfer (ET), excited-state absorption (ESA), cross-relaxation (CR), back energy transfer (BET), and non-radiative relaxation processes (nRP). This underlines the P-tunability of UCNP brightness and color and highlights the potential of P-dependent measurements for mechanistic studies required to manifest the population pathways of the different Er3+ levels.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Llifetime
KW - Sensor
KW - Excitation power density
KW - Single particle
KW - Brightness
KW - NIR
KW - Mechanism
KW - Color tuning
PY - 2021
DO - https://doi.org/10.1007/s12274-021-3350-y
SN - 1998-0124
VL - 14
IS - 11
SP - 4107
EP - 4115
PB - Nano Research
AN - OPUS4-52364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Introduction to Fluorescence Spectroscopy
N2 - A brief introduction to fluorescence spectroscopy will be provided, ranging from typically measured fluorescence quantities over instrument-specific contributions to measured fluorescence signals to selected applications. In this context, an overview of the photoluminescence properties of molecular and nanoscale luminescence reporters will be given including a brief insight into their photophysics and fluorescence standards designed by division Biophotonics for the calibration and instrument performance validation of fluorescence measuring devices will be presented.
T2 - Analytical Academy BAM
CY - Online meeting
DA - 17.11.2020
KW - Fluorescence
KW - Quality assurance
KW - Quantification
KW - Linearity
KW - Measurement uncertainty
KW - Method
KW - Nano particle
KW - Dye
PY - 2020
AN - OPUS4-51619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Design and Quantitative Characterization of Functional Molecular Chromophores and Nanomaterials with UV/vis/NIR/IR Emission and Traceable Optical Measurements
N2 - Research of division Biophotonics at the Federal Institute for Materials Research and Testing (BAM) covers several topics including photophysics of molecular and nanocrystalline emitters, the development of signal enhancement, multiplexing, and barcoding strategies, surface group quantification, the rational design of different types of stimuli-responsive optical probes, and concepts and reference materials for the validation of optical-spectroscopic measurements. In the following representative examples for each of these topics are given. Also, current developments like single particle spectroscopy and flow cytometry with lifetime detection and newly certified fluorescence quantum yield standards are presented.
T2 - Kolloquium BfR
CY - Berlin, Germany
DA - 12.10.2020
KW - Fluorescence
KW - Quantitative spectroscopy
KW - Single particle spectroscopy
KW - Multiplexing
KW - Reference materials
KW - Optical probes
KW - Sensor molecules
KW - Assay
KW - Dye
KW - Quantum yield
KW - Method development
KW - surface group analysis
KW - synthesis
KW - fluorescence standards
PY - 2020
AN - OPUS4-51449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scholtz, Lena
T1 - Luminescent, Semiconductor Nanoparticle-loaded Polymer Microbeads - Comparing Particle Architectures
N2 - The synthesis of luminescent polymer microparticles stained with different, including non-spherical, semiconductor nanoparticles (NPs) was developed and optimized while ensuring a good preservation of the particle photoluminescence. The aplicability of the different semiconductor NPs was determined to depend on their surface chemistry and shape. Thus, a first correlation of semiconductor NP architecture and applicability could be deduced, which has not been reported before.
T2 - 821. WE-Heraeus-Seminar
CY - Bad Honnef, Germany
DA - 12.11.2024
KW - Nanoparticle
KW - Surface chemistry
KW - Synthesis
KW - Fluorescence
KW - Luminescence
PY - 2024
AN - OPUS4-61732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krenzer, Julius
A1 - Mueller, Thomas
T1 - Aroyl-S,N-ketene acetal based bichromophores exhibiting energy transfer and aggregation induced (dual) emission
N2 - A series of aroyl-S,N-ketene acetal based bichromophores is readily synthesized by Buchwald-Hartwig amination and Ullmann reaction in moderate to good yields. The aminated aroyl-S,N-ketene acetals are emissive in the solid state and in the aggregate, but not in solution, thus, they are AIEgens (aggregation induced emission chromogens). Aggregation is induced by fractional alternation of the solvent mixture, here by increasing the water fraction of ethanol/water mixtures. For most derivatives, the emission upon induced aggregation stems solely from the aroyl-S,N-ketene acetal chromophore, regardless whether excitation occurs at the absorption maximum of the triarylamine or the aroyl-S,N-ketene acetal. Therefore, a pronounced energy transfer from the triarylamine donor to the aroyl-S,N-ketene acetal acceptor can be inferred. The color of the emission can be controlled by choosing the para-aroyl substituent. A partial energy transfer could also be observed for some bichromophores, leading to aggregation-induced dual emission (AIDE). In addition, four examples of aminated diaroyl-S,N-ketene acetals were added to the compound library. The electron-withdrawing properties of the additional aroyl group provide a bathochromic shift of the emission band of the aroyl-S,N-ketene acetal. These bichromophores also show AIDE and in one case even aggregation-induced white light emission as a result of additive color mixing.
T2 - Beilstein Symposium on pi-Conjugated Molecules and Materials
CY - Limburg, Germany
DA - 07.11.2023
KW - aggregation-induced dual emission (AIDE)
PY - 2023
AN - OPUS4-59006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - A Multimodal Approach to Quantify Surface Functional Groups on Nanomaterials for Safe and Sustainable by Design
N2 - Engineered nanomaterials (NM) with their large surface-to-volume ratios and their for some materials observed size-dependent functional properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing and electronics or food and consumer products. The performance and safety of NM are determined by the sum of their intrinsic physicochemical properties. Especially, the particle surface chemistry, which is largely controlled by the chemical nature and density of functional groups (FG) and ligands, is an important key driver for NM performance, stability, and processibility as well as the interaction of NM with the environment. Thus, methods for FG quantification can foster the sustainable development of functional and safe(r) NM.
Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG and ligands, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance and thermal analysis methods.
The potential of our multimodal approach for FG quantification was demonstrated for commercial and custom-made polymeric and silica particles of varying FG, used as optical pH sensors. In the future, our strategy can contribute to establish multi-method characterization strategies to provide a more detailed picture of the structure-properties relationship.
T2 - NanoSAFE & NanoSafety Cluster 2023
CY - Grenoble, France
DA - 05.06.2023
KW - Engineered Nanomaterials
KW - Safe-by-Design
KW - Sustainable-by-Design
KW - Surface Group Analysis
KW - Silica and Polystyrene Particles
KW - Surface Modification
KW - Dye
KW - Optical Spectroscopy
KW - Quantitative NMR
KW - Electrochemical Titration
KW - Functionalized Nanomaterials
KW - Nanosafety
PY - 2023
AN - OPUS4-59126
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Osipova, Viktoriia
T1 - Incorporation of near-infrared light emitting chromium (III) complexes into silica nanoparticles and spectroscopic characterization
N2 - In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters triggered by the report on the first molecular ruby Cr(ddpd)2(BF4)3 with a high photoluminescence quantum yield of 13.7% of its near infrared (NIR) emission band and a long luminescence lifetime of 1.122 ms at room temperature.[1] However, in an oxygen-containing environment, the photoluminescence quantum yields and luminescence lifetimes of these chromium(III) complexes show only very small values. This hampers their application as NIR luminescence labels. This application, that cannot be tackled by conventional deoxygenating approaches, requires suitable strategies to protect the luminescence of the chromium(III) complexes from oxygen quenching. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into different types of amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. In this work, as first proof-of-concept experiments, a set of chromium (III) complexes constituting of different ligands and counter anions, were embedded into the core of silica nanoparticles. Subsequently, the optical properties of the resulting luminescent silica nanoparticles were spectroscopically assessed by steady state and time-resolved luminescence spectroscopy. First results of time-resolved luminescence measurements confirm our design concept of nanoscale NIR emissive Cr(III) complex-based reporters
T2 - Projekttreffen Nile-Chrome 2.0
CY - Mainz, Germany
DA - 11.12.2023
KW - Cr(III) complex
KW - NIR
KW - Luminescence
KW - Nano
KW - Silica
KW - Lifetime
KW - Quantum Yields
KW - Particle Synthesis
KW - Sensors
KW - Probe
KW - Surface Group Analysis
PY - 2023
AN - OPUS4-59149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, M.
A1 - Zhang, R.
A1 - Fa, X.
A1 - Yang, J.
A1 - Cheng, Z.
A1 - Qiao, X.
A1 - Ou, J.
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Core−Shell NaYF4:Yb3+/Tm3+@NaGdF4:Ce3+/Eu3+ Nanoparticles for Upconversion and Downconversion Dual-Mode Fluorescence-Based Temperature Sensing
N2 - NaYF4 as the core and NaGdF4 as the outer layer were used to obtain
NaYF4:Yb3+/Tm3+@NaYF4:Ce3+/Eu3+ nanoparticles. Physical and morphological investigations indicated that the obtained nanoparticles were prepared in a hexagonal shape, with the NaGdF4 shell layer uniformly encapsulated on the NaYF4 core.
Strong Tm3+ upconversion emission peaks were observed for a 980-nm-laser-excited sample, while strong Eu3+ downconversion emission peaks were observed for a 254-nm-laser-excited sample. By zonal doping of Tm3+ and Eu3+, their fluorescence intensity can be significantly increased; more importantly, simultaneous temperature measurements with dual-mode upconversion/downconversion can be achieved. The temperature measurement properties of the dual mode were also investigated, and it was discovered that the upconversion 3F3 → 3H6 and 1G4 → 3F4 thermocouple energy levels gave the best temperature measurements with maximum absolute and relative sensitivities of 0.0877 K−1 and 1.95% K−1, respectively, which are better than the current temperature measurement sensitivities of most rare-earth-based materials. This material was prepared as fiber-optic temperature-sensing probes to detect the temperature in the environment in real time and was found to perform excellently for temperature measurement.
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Sensing; temperature
KW - Photophysics
PY - 2022
DO - https://doi.org/10.1021/acsanm.2c01611
VL - 5
IS - 7
SP - 9266
EP - 9276
PB - American Chemical Society
AN - OPUS4-55363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Manley, P.
A1 - Voigt, R.
A1 - Ahiboz, D.
A1 - Becker, C.
A1 - Resch-Genger, Ute
T1 - Metasurface Enhanced Sensitized Photon Upconversion: Toward Highly Efficient Low Power Upconversion Applications and Nanoscale E-Field Sensors
N2 - Large-scale nanoimprinted metasurfaces based on silicon photonic crystal slabs were produced and coated with a NaYF4:Yb3+/Er3+ upconversion nanoparticle (UCNP) layer. UCNPs on these metasurfaces yield a more than 500-fold enhanced upconversion emission compared to UCNPs on planar surfaces. It is also demonstrated how the optical response of the UCNPs can be used to estimate the local field energy in the coating layer. Optical simulations using the finite element method validate the experimental results and the calculated spatial three-dimensional field Energy distribution helps us to understand the emission enhancement mechanism of the UCNPs closely attached to the metasurface. In addition, we analyzed the spectral shifts of the resonances for uncoated and coated metasurfaces and metasurfaces submerged in water to enable a prediction of the optimum layer thicknesses for different excitation wavelengths, paving the way to applications such as electromagnetic field sensors or bioassays.
KW - Nanoparticles
KW - Upconversion
KW - Metasurface
KW - Field sensor
KW - Emission enhancement
KW - Photonic crystal
PY - 2020
DO - https://doi.org/10.1021/acs.nanolett.0c02548
VL - 20
IS - 9
SP - 6682
EP - 6689
PB - ACS Publications
AN - OPUS4-51427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geißler, Daniel
T1 - Development of reference materials for flow cytometric analysis of extracellular vesicles
N2 - The aim of task 1.4 within the EMPIR project 18HLT01 MetVesII is to produce low-RI solid particles with an effective RI between 1.37 and 1.42. To prepare these low-RI solid particles, polymer cores will be coated with a silica shell. Although the bulk RI of polymers, such as polystyrene (RI = 1.59) and PMMA (RI = 1.49), and fused silica (RI = 1.46) are higher than desired, an effective RI below 1.42 will be achieved by using a mesoporous silica shell with tuneable shell-thickness and a polymer core with sufficiently small size. This approach has four advantages: (1) monodisperse commercial polymer particles and silica shell chemistry are available, (2) low-RI solid particles will have a tuneable size and RI, (3) fluorescence can be added by incorporating fluorescent dyes into the polymer cores via an established staining procedure, and (4) fluorescent dyes within the polymer cores are shielded against influences from the sample matrix, e.g. fluorescence quenching effects altering the emission properties of the reference materials.
T2 - MetVesII M9 Progress Meeting
CY - Budapest, Hungary
DA - 12.02.2020
KW - EMPIR 18HLT01 MetVesII
KW - Extracellular vesicles (EV)
KW - Flow cytometry (FCM)
KW - Reference materials
KW - Fluorescent particles
PY - 2020
AN - OPUS4-50451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Functional Luminophores – From Photophysics to Standardized Luminescence Measurements
N2 - Inorganic nanocrystals with linear and nonlinear luminescence in the ultraviolet, visible, near infrared and short-wave infrared like semiconductor quantum dots and spectrally shifting lanthanide-based nanophosphors have meanwhile found applications in the life and material sciences ranging from optical reporters for bioimaging and sensing over security barcodes to solid state lighting and photovoltaics. These nanomaterials commonly have increasingly sophisticated core/shell particle architectures with shells of different chemical composition and thickness to minimize radiationless deactivation at the particle surface that is usually the main energy loss mechanism [1]. For lanthanide-based spectral shifters, particularly for very small nanoparticles, also surface coatings are needed which protect near-surface lanthanide ions from luminescence quenching by high energy vibrators like O-H groups and prevent the disintegration of these nanoparticles under high dilution conditions. [2,3,4]. The identification of optimum particle structures requires quantitative spectroscopic studies focusing on the key performance parameter photoluminescence quantum yield [5,6], ideally flanked by single particle studies to assess spectroscopic inhomogeneities on a particle-to-particle level for typical preparation methods [7,8], Moreover, in the case of upconversion nanoparticles with a multi-photonic and hence, excitation power density (P)-dependent luminescence, quantitative luminescence studies over a broad P range are required to identify particle architectures that are best suited for applications in fluorescence assays up to fluorescence microscopy. Here, we present methods to quantify the photoluminescence of these different types of emitters in the vis/NIR/SWIR and as function of P and demonstrate the importance of such measurements for a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different size and particle architecture in different environments.
T2 - Eingeladener Vortrag Uni Erlangen
CY - Erlangen, Germany
DA - 18.01.2023
KW - Semiconductor quantum dot
KW - Upconversion nanocrystal
KW - Luminescence
KW - Quantitative spectroscopy
KW - Photophysics
KW - Quality assurance
KW - Nano
KW - Particle
KW - Quantum yield
KW - Lifetime
KW - Standard
KW - Reference material
KW - Surface analysis
KW - Quantification
PY - 2023
AN - OPUS4-57011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - pH-Responsive Dyad Molecules: MiGraGen Project
N2 - Optical pH sensors utilizing colorimetric or fluorescent indicator dyes are highly promising in many biomedical and life science applications where electrochemical sensors fail. For instance, optical sensors are not prone to electrical interferences, they are noninvasive and enable remote measurements. Moreover, fluorescence detection is very fast, highly sensitive, and provides several readout parameters ideal for multiplexing with nanometer resolution using simple, inexpensive, and miniaturizable instrumentation. Here, we present the design of a dyad sensor molecule, consisting of an analyte-responsive and an analyte inert reference fluorophore.
T2 - MiGraGen Project Meeting 16.06.2023
CY - Online Meeting
DA - 16.06.2023
KW - Dyad molecules
KW - pH sensing
KW - Fluorescent indicator
KW - Ratiometric sensors
PY - 2023
AN - OPUS4-58070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - Luminescent Quantum dots – the next-generation nano light bulbs
N2 - Fluorescent semiconductor nanocrystals, also known as quantum dots (QDs), enabled many advancements in biotechnology, photovoltaics, photocatalysis, quantum computing and display devices. The high versatility of this nanomaterial is based on their unique size-tunable photoluminescence properties, which can be adjusted from the visible to the near-infrared range. In contrast to other nanomaterials, QDs made the transition from a laboratory curiosity to the utilization in commercial products, like the QLED television screen or in smartphone displays. The best investigated QDs are composed of heavy metals like cadmium or lead, which is not the best choice in terms of toxicity and environmental pollution. A more promising material is Indium Phosphide (InP), which is also currently used by Samsung, Sony and co. in the QLED displays.
In this contribution, I would like to give you a sneak peek behind the curtains of nanomaterial synthesis and show how this material is produced, how to stabilize their structural properties, and assess their toxicity in environmentally relevant conditions. Furthermore, I would like to present a synthesis method to accomplish the last open challenge in display technology of a blue luminescent LED based on QDs by introducing a new element to the InP QDs.
T2 - The Berlin Postdoc Day
CY - Berlin, Germany
DA - 03.11.2022
KW - InP
KW - Quantum dots
KW - Fluorescence
KW - Aging
KW - Doping
KW - Nanomaterial
KW - Cytotoxicity
PY - 2022
AN - OPUS4-56194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - A journey in science from a graduate student in physical chemistry to head of division biophotonics
N2 - I will provide a personal overview of the most important steps of my career in science, a journey from a graduate student in physical chemistry in an environment dominated by male-scientists over a postdoc with a female professor in the US to the leader of a research group, head of division Biophotonics at BAM. This will include my choices of research topics, how I learnt to write well cited publications, even on topics such as reference materials and quality assurance,1-4 and eventually started to give lectures at Free University Berlin granting me the right to act as first supervisor of undergraduate and graduate students.
T2 - Women in Science
CY - Erlangen, Germany
DA - 22.07.2024
KW - Lanthanide
KW - Nanoparticle
KW - Silica
KW - Quantum dot
KW - Polymer
KW - Surface group
KW - Luminescence
KW - Quantitative spectroscopy
KW - Quantum yield
KW - Lifetime
KW - Quality assurance
KW - Synthesis
KW - Surface modification
KW - Photophysics
PY - 2024
AN - OPUS4-60724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - Exploring the photoluminescence of gold NCs and Ag2S NPs to boost their SWIR emission
N2 - Current challenges and objectives for non-invasive optical bioimaging are deep tissue penetration, high detection sensitivity, high spatial and temporal resolution, and fast data acquisition. A promising spectral window to tackle these challenges is the short-wave infrared (SWIR) ranging from 900 nm to 1700 nm where scattering, absorption, and autofluorescence of biological components are strongly reduced compared to the visible/NIR. At present, the best performing SWIR contrast agents are based on nanomaterials containing toxic heavy-metal ions like cadmium or lead, which raises great concerns for biological applications. Promising heavy-metal free nanoscale candidates are gold nanoclusters (AuNCs) and Ag2S nanoparticles (NPs). The photoluminescence (PL) of both types of nanomaterials is very sensitive to their size, composition of their surface ligand shell, and element composition, which provides an elegant handle to fine-tune their absorption and emission features and boost thereby the size of the signals recorded in bioimaging studies.
Aiming for the development of SWIR contrast agents with optimum performance, we dived deeper into the photophysical processes occurring in these nanomaterials, thereby exploring in depth how the environment, surface ligand composition, and the incorporation of transition metals influence the optical properties of AuNCs and Ag2S NPs. We observed a strong enhancement of the SWIR emission of AuNCs upon exposure to different local environments (in solution, polymer, and in the solid state). Addition of metal ions such as Zn2+ to Ag2S based NPs led to a strong PL enhancement, yielding PL quantum yields of about 10% and thus making them highly suitable for non-invasive deep imaging of vascular networks and 3D fluid flow mapping.
T2 - NaNaX 10 - Nanoscience with Nanocrystals
CY - Klosterneuburg, Austria
DA - 03.07.2023
KW - Quantum dots
KW - Ag2S
KW - Fluorescence
KW - SWIR
KW - Gold nanocluster
KW - Nanomaterial
KW - bioimaging
PY - 2023
AN - OPUS4-58104
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Functional molecular chromophores and nanomaterials reporters, optical probes, and sensors
N2 - •Overview of expertise of division Biophotonics
•Functional molecular and nanoscale luminescent reporters, probes, and
sensors including design principles available from division Biophotonics
•Examples for pH and O2 responsive molecular probes and particle sensors
•Surface group quantification Analytical methods and cleavable probes
•Concepts & standards for the validation and traceability of optical measurements
T2 - FU-Seminar
CY - Berlin, Germany
DA - 09.12.2022
KW - Particle sensors
KW - Surface group quantification
KW - Nanoscale luminescent reporters
KW - Cleavable probes
PY - 2022
AN - OPUS4-56526
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matiushkina, Anna
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Richstein, R.
A1 - Reithofer, M. R.
A1 - Andresen, Elina
A1 - Michaelis, Matthias
A1 - Koch, Matthias
A1 - Resch-Genger, Ute
T1 - Quantifying Citrate Surface Ligands on Iron Oxide Nanoparticles with TGA, CHN Analysis, NMR, and RP-HPLC with UV Detection
N2 - Although citrate is frequently used as a surface ligand for nanomaterials (NMs) such as metal, metal oxide, and lanthanide-based NMs in hydrophilic environments due to its biocompatibility and simple replacement by other more strongly binding ligands in postsynthetic surface modification reactions, its quantification on NM surfaces has rarely been addressed. Here, we present a multimethod approach for citrate quantification on iron oxide nanoparticles (IONPs) broadly applied in the life and material sciences. Methods explored include thermogravimetric (TGA) and elemental (CHN) analysis, providing citrate-nonspecific information on the IONP coating, simple photometry, and citrate-selective reversed-phase high-performance liquid chromatography (RP-HPLC) with absorption (UV) detection and quantitative nuclear magnetic resonance spectroscopy (qNMR). Challenges originating from the strongly absorbing magnetic NM and paramagnetic iron species interfering with optical and NMR Methods were overcome by suitable sample preparation workflows. Our multimethod approach to citrate quantification highlights the advantages of combining specific and unspecific methods for characterizing NM Surface chemistry and method cross-validation. It also demonstrates that chemically nonselective measurements can favor an overestimation of the amount of a specific surface ligand by signal contributions from molecules remaining on the NM surface, e.g., from particle synthesis, such as initially employed ligands and/or surfactants. Our results emphasize the potential of underexplored selective RPHPLC for quantifying ligands on NMs, which does not require a multistep sample preparation workflow such as qNMR for many NMs and provides a higher sensitivity. These findings can pave the road to future applications of versatile HPLC methods in NM characterization.
KW - Advanced material
KW - Functional group
KW - Iron oxide
KW - Ligand
KW - Nano
KW - Particle
KW - Quantification
KW - Surface analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648632
DO - https://doi.org/10.1021/acs.analchem.5c03024
SN - 0003-2700
VL - 97
IS - 36
SP - 19627
EP - 19634
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-64863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Photoluminescence quantum yields of molecular & nanoscale luminophores in the UV/VIS/NIR/SWIR in dispersion and in the solid state
N2 - Photophysical and mechanistic studies, the comparison of different emitter classes, and the rational design of the next generation of molecular and nanoscale reporters require quantitative photoluminescence measurements and the reliable determination of the key performance parameter photoluminescence quantum yield (QY), i.e., the number of emitted per absorbed photons. This is of special importance for all photoluminescence applications in the life and material sciences in the UV/vis/NIR/SWIR.
T2 - MAF 2024 Conference
CY - Valencia, Spain
DA - 08.09.2024
KW - Nanoparticle
KW - Nano
KW - Luminescence
KW - Quality assurance
KW - Synthesis
KW - Standardization
KW - Reference material
KW - Quantum yield
KW - Fluorescence
KW - Reference data
KW - Integrating sphere spectroscopy
KW - ILC
KW - Converter material
PY - 2024
AN - OPUS4-61072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauli, J.
A1 - Güttler, Arne
A1 - Schneider, T.
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Fluorescence Quantum Yield Standards for the UV/Visible/NIR: Development, Traceable Characterization, and Certification
N2 - The rational design of next generation molecular and nanoscale reporters and the comparison of different emitter classes require the determination of the fluorometric key performance parameter fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. Main prerequisites for reliable Φf measurements, which are for transparent luminophore solutions commonly done relative to a reference, i.e., a fluorescence quantum yield standard of known Φf, are reliable and validated instrument calibration procedures to consider wavelength-, polarization-, and time-dependent instrument specific signal contributions, and sufficiently well characterized fluorescence quantum yield standards. As the standard’s Φf value directly contributes to the calculation of the sample’s Φf, its accuracy presents one of the main sources of uncertainty of relative Φf measurements. To close this gap, we developed a first set of 12 fluorescence quantum yield standards, which absorb and emit in the wavelength region of 330−1000 nm and absolutely determined their Φf values with two independently calibrated integrating sphere setups.
Criteria for standard selection and the configuration of these novel fluorescence reference materials are given, and the certification procedure is presented including homogeneity and stability studies and the calculation of complete uncertainty budgets for the certified Φf values. The ultimate goal is to provide the community of fluorescence users with available reference materials as a basis for an improved comparability and reliability of quantum yield data since the measurement of this spectroscopic key property is an essential part of the characterization of any new emitter.
KW - Optical spectroscopy
KW - Traceability
KW - Reference product
KW - Dye
KW - Fluorescence
KW - Quantum yield
KW - Reference material
KW - Reference data
KW - Certification
KW - Quality assurance
PY - 2023
DO - https://doi.org/10.1021/acs.analchem.2c05530
VL - 95
SP - 5671
EP - 5677
PB - American Chemical Society
AN - OPUS4-58151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Absolute determination of photoluminescence quantum yields of scattering led converter materials how to get it right
N2 - Scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders are increasingly relevant for fundamental research and industry. Examples are luminescent nano- and microparticles and phosphors of different compositions in various matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics. A key performance parameter is the photoluminescence quantum yield (Φf), i.e., the number of emitted per number of absorbed photons. Φf of transparent luminophore solutions can be obtained relative to a fluorescence Φf standard of known Φf, meanwhile available as certified reference materials.[1] The determination of Φf of scattering liquid and solid samples requires, however, absolute measurements with an integrating sphere setup.
Fist we present the results of an interlaboratory comparison of 3 labs from academia and industry on measurements of transparent and scattering dye solutions and YAG:Ce optoceramics, an optical converter material, with commercial stand-alone integrating sphere setups of different illumination and detection geometries.[2] Second we present results for a series of 500 μm-thick polymer films containing different concentrations of photoluminescent and scattering YAG:Ce microparticles.[3] We systematically explored and quantified pitfalls of absolute Φf measurements with special emphasis dedicated to the influence of measurement geometry, optical properties of the blank for determining the number of incident photons absorbed by the sample, and sample-specific surface roughness. Matching Φf values could be easily obtained for transparent dye solutions and scattering dispersions with a blank with scattering properties closely matching those of the sample, Φf measurements of optoceramic samples with different blanks revealed substantial differences of more than 20 %. Our results further reveal that setup configurations can introduce systematic errors resulting in under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf.
T2 - Shift 2025
CY - La Laguna, Tenerife, Spain
DA - 13.10.2025
KW - Quantum Yield
KW - LED Converter
KW - Luminescent
KW - Microparticles
PY - 2025
AN - OPUS4-64785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andresen, Elina
T1 - Non-spherical monodisperse multi-element LiYF4:Yb,Tm nanoparticles as potential reference materials for sizing methods – Design, synthesis & characterization
N2 - The use of engineered nanoparticles of different size, shape, and composition is continuously increasing in the life and material sciences. This calls for methods and reference materials enabling the reliable and accurate determination of nanoparticle size, particle size distribution, shape, and number concentration. For nano-object with a simple, i.e, spherical shape, the size can be easily determined from measurements of a single parameter, i.e., diameter, by electron microscopy. For non-spherical particles, that much better reflect the properties of most industrially relevant nanomaterials, new correlative approaches for complete 3D characterization are needed and non-spherical reference particles for establishing such methods and the implementation and validation of the respective data fitting routine are compulsory. Therefore, we are currently exploring the potential of differently sized, bipyramidally shaped LiYF4-based NCs doped with different lanthanide ions as reference materials for sizing methods.
T2 - E-MRS Spring
CY - Strasbourg, France
DA - 27.05.2024
KW - Non-sperical NPS
KW - Reference materials
KW - SAXS
PY - 2024
AN - OPUS4-62133
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goryacheva, O. A.
A1 - Wegner, Karl David
A1 - Sobolev, A. M.
A1 - Häusler, I.
A1 - Gaponik, N.
A1 - Gorycheva, I. Y.
A1 - Resch-Genger, Ute
T1 - Influence of particle architecture on the photoluminescence properties of silica‑coated CdSe core/shell quantum dots
N2 - Light-emitting nanoparticles like semiconductor nanocrystals (termed quantum dots, QDs) are promising candidates for biosensing and bioimaging applications based on their bright and stable photoluminescent properties. As high-quality QDs are often synthesized in organic solvents, strategies needed to be developed to render them water-dispersible without affecting their optical properties and prevent changes in postmodification steps like the biofunctionalization with antibodies or DNA. Despite a large number of studies on suitable surface modification procedures, the preparation of water-soluble QDs for nanobiotechnology applications still presents a challenge. To highlight the advantages of surface silanization, we systematically explored the influence of the core/multishell architecture of CdSe/CdS/ZnS QDs and the silanization conditions on the optical properties of the resulting silanized QDs. Our results show that the optical properties of silica-coated CdSe/CdS/ZnS QDs are best preserved in the presence of a thick CdS (6 monolayers (ML)) intermediate shell, providing a high photoluminescence quantum yield (PL QY), and a relatively thick ZnS (4.5 ML) external shell, effectively shielding the QDs from the chemical changes during silica coating. In addition to the QD core/shell architecture, other critical parameters of the silica-coating process, that can have an influence on the optical properties of the QD, include the choice of the surfactant and its concentration used for silica coating. The highest PL QY of about 46% was obtained by a microemulsion silica-coating procedure with the surfactant Brij L4, making these water-dispersible QDs to wellsuited optical reporters in future applications like fluorescence immunoassays, biomedicine, and bioimaging.
KW - Nano
KW - Nanomaterial
KW - Particle
KW - Semiconductor
KW - Quantum do
KW - Photoluminescence
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Mechanism
KW - Surface
KW - Shell
KW - Silica
KW - Silanization
KW - Synthesis
PY - 2022
DO - https://doi.org/10.1007/s00216-022-04005-7
SP - 1
EP - 13
PB - Springer
AN - OPUS4-54546
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Absolute Determination of Photoluminescence Quantum Yields of Scattering LED Converter Materials – How to Get it Right
N2 - Optical measurements of scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders play an important role in fundamental research and industry. Typical examples are luminescent nano- and microparticles and phosphors of different composition in different matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter for the performance of these materials is the photoluminescence quantum yield QY, i.e., the number of emitted photons per number of absorbed photons. QY of transparent luminophore solutions can be determined relatively to a fluorescence quantum yield standard of known QY. Such standards are meanwhile available as certified reference materials.[1] The determination of QY of scattering liquid and solid samples like dispersions of luminescent nanoparticles, solid phosphors, and optoceramics requires, however, absolute measurements with an integrating sphere setup. Although the importance of reliable absolute QY measurements has been recognized, no interlaboratory comparisons (ILCs) on measurement uncertainties and the identification of typical sources of uncertainty have been yet reported. Also, no scattering reference materials with known QY are available.
We present here the results of a first ILC of 3 laboratories from academia and industry performed to identify and quantify sources of uncertainty of absolute QY measurements of scattering samples. Thereby, two types of commercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring QY of transparent and scattering dye solutions and solid phosphors. As representative and industrially relevant solid and scattering samples, YAG:Ce optoceramics of varying surface roughness were chosen, applied, e.g., as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank, utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While matching QY values could be obtained for transparent dye solutions and scattering dispersions, here using a blank with scattering properties closely matching those of the sample, QY measurements of optoceramic samples with different blanks revealed substantial differences, with the blank's optical
properties accounting for measurement uncertainties of more than 20 %. Based upon the ILC results, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder which reveals a near-Lambertian light scattering behavior, yielding a homogeneous light distribution within the integrating sphere.
T2 - e-MRS 2024
CY - Strasbourg, France
DA - 27.05.2024
KW - Luminescence
KW - Quantitative spectroscopy
KW - Nano
KW - Particle
KW - Quantum yield
KW - Lifetime
KW - Quality assurance
KW - Phosphor
KW - Converter marterial
KW - Fluorescence
KW - Interlaboratory
KW - Comparison
KW - Method
KW - Uncertainty
KW - Reference material
PY - 2024
AN - OPUS4-60490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Development of amorphous silica particle based reference materials for surface functional group quantification
N2 - Functionalized nanomaterials (NM) with their unique size-dependent properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing, electronics or food and consumer products. The performance and safety of NM are determined by the sum of their intrinsic physicochemical properties.1 Besides other key parameters, the particle surface chemistry, which is largely controlled by the chemical nature and density of functional groups and ligands, must be considered for a better performance, stability, and processibility of NM, as well as their interaction with the environment. Thus, particle standards with well-designed surfaces and methods for functional group quantification can foster the sustainable development of functional and safe(r) NM.2 Here we provide a brief overview of the ongoing research in division Biophotonics to design tailored amorphous silica reference particles with bioanalytically relevant functional groups and ligands, for the development of standardized and validated surface functional group quantification methods.
T2 - Workshop NanoRiskSD project
CY - Berlin, Germany
DA - 09.06.2022
KW - Nanoparticle
KW - Surface analysis
KW - Silica
KW - Fluorescence
KW - Assay
PY - 2022
AN - OPUS4-55004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Rational Design of Analyte-responsive Fluorescent Particle Sensors for Life Sciences Applications
N2 - Engineered and tailor-made nanomaterials (NM) are of increasing relevance for current and future developments in the life and material sciences for applications, e.g., as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays, and reporters for imaging applications. For instance, NM-based reporters and sensors, that are labelled or stained with a multitude of conventional or sensor dyes, have several advantages as compared to molecular probes like enhanced brightness, i.e., amplified signals, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, this can enable the use of hydrophobic dyes in aqueous environments. For rational NM design, choosing and tailoring the intrinsic physicochemical properties, such as particle size, size distribution, morphology, and surface chemistry of the NM application-specific considerations like biocompatibility, ease and low cost of preparation, and colloidal stability and performance in the targeted environment must be considered. In this lecture, different design concepts of inorganic, organic, and hybrid NM and microparticles with hydrophilic surface chemistries and different functionalities are presented that can be used for the targeting of lysosomes; and to monitor functional parameters of endo-lysosomal compartments, like pH or enable oxygen sensing.
T2 - Chemical Probes for Lysosomal Biology
CY - York, United Kingdom
DA - 09.09.2024
KW - Luminescence
KW - Quantification
KW - Nano
KW - Particle
KW - Quality assurance
KW - Fluorescence
KW - Method
KW - Uncertainty
KW - Reference material
KW - Sensor
KW - Synthesis
KW - Dye
KW - pH
KW - Silica
KW - Polystyrene
KW - Surface analysis
PY - 2024
AN - OPUS4-62173
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Multicolored sensors based on silica and polymeric particles for ratiometric monitoring of pH, oxygen and saccharides
N2 - In recent years, the use of functionalized micro- and nanomaterials has increased rapidly for a wide range of applications in the life and material sciences, due to their unique properties in combination with their high surface-to-volume ratio and stability. For instance, functionalized micro- and nanomaterials, that are labeled or stained with a multitude of sensor dyes can be used for monitoring, and quantification of neutral and ionic analytes. These materials have several advantages as compared to conventional molecular probes like enhanced brightness, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, stained nanoparticles can enable the use of hydrophobic dyes in aqueous environments.
Versatile templates and carriers for the fabrication of nanosensors by staining and/or labeling with different fluorophores and sensor molecules are biocompatible silica and polymeric particles, because they can be synthesized in large scales at low costs with different surface chemistries.
Here we present our work on multicolored sensors for the measurement of pH, oxygen and saccharides utilizing commercially available or in-house synthesized silica and polymeric particles.
T2 - 4th European Biosensor Symposium 2023
CY - Aachen, Deutschland
DA - 27.08.2023
KW - Nano- and microsensors
KW - Silica and polystyrene nanoparticles
KW - PH probe
KW - Ratiometric sensors
KW - Optical spectroscopy
KW - Dye
KW - Saccharide sensing
KW - Multicolored
PY - 2023
AN - OPUS4-59125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - New project on the quantification of functional groups (FGS) on nanomaterials
N2 - The surface chemistry of nanomaterials controls their interaction with the environment and biological species and their fate and is hence also relevant for their potential toxicity. This has meanwhile led to an increasing interest in validated and preferably standardized methods for the determination and quantification of surface functionalities on nanomaterials and initiated different standardization projects within ISO/TC 229 and IEC/TC 113 as well as interlaboratory comparisons (ILCs) of different analytical methods for the quantification of surface coatings by OECD. Here we present the results of a first ILC on the quantification of the amount of amino functionalities on differently sized inorganic nanoparticles done by division Biophotonics and the National Research Council of Canada (NRC) and the PWI 19257 on the Characterization and Quantification of Surface Functional Groups and Coatings on Nanoobjects approved by ISO/TC 229 (WG2) in fall 2022 that will result in a VAMAS study on this topic organized by division Biophotonics. Key words: nanoparticles, surface analysis, surface functional groups, quantification, optical assay, qNMR, VAMAS, standardization, ICL, quality assurance, reference material.
T2 - Eingeladener Vortrag Universität Erlangen
CY - Erlangen, Germany
DA - 18.01.2023
KW - Quality assurance
KW - Nano
KW - Particle
KW - Standard
KW - Reference material
KW - Surface analysis
KW - Quantification
KW - Interlaboratory comparison
KW - Standardization
KW - VAMAS
PY - 2023
AN - OPUS4-57044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matiushkina, Anna
T1 - Quantification of Citrate Ligands on the Surface of Nanoparticles
N2 - In this study, different methods for determining nanoparticle surface ligands including thermogravimetric analysis (TGA) are explored to quantify citrate as one of the most popular hydrophilic ligands on the surface of nanoparticles such as iron oxide nanoparticles (IONPs). The purpose of work is to understand which analytical methods are best suited for surface chemistry analysis of citrate stabilized IONPs and to validate these methods.
T2 - SALSA Make and Measure 2024: Interfaces
CY - Berlin, Germany
DA - 11.09.2024
KW - Nano
KW - Particle
KW - Iron oxide
KW - Ligand
KW - Quantification
KW - Advanced material
KW - Surface analysis
KW - Functional group
PY - 2024
AN - OPUS4-62298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tan, M.
A1 - Monks, Melissa-Jane
A1 - Huang, D.
A1 - Meng, Y.
A1 - Chen, X.
A1 - Zhou, Y
A1 - Lom, S.-F.
A1 - Würth, Christian
A1 - Resch-Genger, Ute
A1 - Chen, G.
T1 - Efficient sub-15 nm cubic-phase core/Shell upconversion nanoparticles as reporters for ensemble and single particle studies†
N2 - Single particle imaging of upconversion nanoparticles (UCNPs) has typically been realized using hexagonal (β) phase lanthanide-doped sodium yttrium fluoride (NaYF4) materials, the upconversion luminescence (UCL) of which saturates at power densities (P) of several hundred W cm−2 under 980 nm nearinfrared (NIR) excitation. Cubic (α) phase UCNPs have been mostly neglected because of their commonly observed lower UCL efficiency at comparable P in ensemble level studies. Here, we describe a set of sub-15 nm ytterbium-enriched α-NaYbF4:Er3+@CaF2 core/shell UCNPs doped with varying Er3+ concentrations (5–25%), studied over a wide P range of ∼8–105 W cm−2, which emit intense UCL even at a low P of 10 W cm−2 and also saturate at relatively low P. The highest upconversion quantum yield (ΦUC) and the highest particle brightness were obtained for an Er3+ dopant concentration of 12%, reaching the highest ΦUC of 0.77% at a saturation power density (Psat) of 110 W cm−2. These 12%Er3+-doped core/shell UCNPs were also the brightest UCNPs among this series under microscopic conditions at high P of ∼102–105 W cm−2 as demonstrated by imaging studies at the single particle level. Our results underline the potential applicability of the described sub-15 nm cubic-phase core/shell UCNPs for ensemble- and single particle-
level bioimaging.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Surface chemistry
KW - Single particle
KW - Brightness
PY - 2020
DO - https://doi.org/10.1039/d0nr02172e
VL - 12
IS - 19
SP - 10592
EP - 10599
PB - Nanoscale
AN - OPUS4-50908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunc, F.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Rühle, Bastian
A1 - Sung, Y.
A1 - Johnston, L.J.
A1 - Resch-Genger, Ute
T1 - Interlaboratory Comparison on the Quantification of Total and Accessible Amine Groups on Silica Nanoparticles with qNMR and Optical Assays
N2 - Risk assessment of nanomaterials requires not only standardized toxicity studies but also validated methods for nanomaterial surface characterization with known uncertainties. In this context, a first bilateral interlaboratory comparison on Surface group quantification of nanomaterials is presented that assesses different reporter-free and labeling methods for the quantification of the total and accessible number of amine functionalities on commercially available silica nanoparticles that are widely used in the life sciences. The overall goal of this comparison is the identification of optimum methods as well as achievable measurement uncertainties and the comparability of the results across laboratories. We also examined the robustness and ease of implementation of the applied analytical methods and discussed method-inherent limitations. In summary, this comparison presents a first step toward the eventually required standardization of methods for surface group quantification.
KW - Nano
KW - Nanomaterial
KW - Surface
KW - Method
KW - QNMR
KW - Quantification
KW - Comparison
KW - Quality assurance
KW - Optical probe
KW - Sensor
KW - Interlabority comparison
KW - Standardization
KW - Optical assay
KW - Functional group analysis
KW - Silica
KW - Particle
KW - Safety
KW - Environment
PY - 2021
DO - https://doi.org/10.1021/acs.analchem.1c02162
SN - 1520-6882
VL - 93
IS - 46
SP - 15271
EP - 15278
PB - ASC Publications
AN - OPUS4-53818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Billimoria, K.
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Goenaga-Infante, H.
T1 - A Strategy for Quantitative Imaging of Lanthanide Tags in A549 Cells Using the Ratio of Internal Standard Elements
N2 - One remaining handicap for spatially resolved elemental quantification in biological samples is the lack of a suitable internal standard (IS) that can be reliably measured across both calibration standards and samples. In this work, multielement quantitative intracellular imaging of cells tagged with lanthanide nanoparticles containing key lanthanides, e.g., Eu and Ho, is described using a novel strategy that uses the ratio of IS elements and LA-ICP-TOFMS analysis. To achieve this, an internal standard layer is deposited onto microscope slides containing either gelatin calibration standards or Euand Ho-tagged cell samples. This IS layer contains both gallium (Ga) and indium (In).
Monitoring either element as an IS individually showed significant variability in intensity signal between sample or standards prepared across multiple microscope slides, which is indicative of the difficulties in producing a homogeneous film at intracellular resolution.
However, normalization of the lanthanide signal to the ratio of the IS elements improved the calibration correlation coefficients from 0.9885 to 0.9971 and 0.9805 to 0.9980 for Eu and Ho, respectively, while providing a consistent signal to monitor the ablation behavior between standards and samples. By analyzing an independent quality control (QC) gelatin sample spiked with Eu and Ho, it was observed that without normalization to the IS ratio the concentrations of Eu and Ho were highly biased by approximately 20% in comparison to the expected values.
Similarly, this overestimation was also observed in the lanthanide concentration distribution of the cell samples in comparison with
the normalized data.
KW - Nanoparticle
KW - Nano
KW - Luminescence
KW - Quality assurance
KW - Synthesis
KW - Standardization
KW - Reference material
KW - ICP-MS
KW - LA-ICP-MS
KW - Quantification
KW - Bioimaging
PY - 2024
DO - https://doi.org/10.1021/acs.analchem.4c02763
SN - 0003-2700
VL - 96
IS - 30
SP - 12570
EP - 12576
AN - OPUS4-60768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Scholtz, Lena
A1 - Resch-Genger, Ute
T1 - Behind the Paper - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies
N2 - In this contribution we highlight the importance of comparison for scientific research while developing a new, functional pH sensor system, and the valuable insights this can provide.
KW - Dye
KW - Optical Spectroscopy
KW - pH probe
KW - Silica and Polystyrene Particles
KW - Nano
KW - Surface groups
KW - Safe-by-Design
KW - Cell studies
KW - Sensors
KW - Particle Synthesis
KW - Fluorescence
PY - 2023
UR - https://communities.springernature.com/posts/dual-color-ph-probes-made-from-silica-and-polystyrene-nanoparticles-and-their-performance-in-cell-studies
SP - 1
EP - 2
PB - Springer Nature
CY - London
AN - OPUS4-59150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monks, M.-J.
A1 - Würth, Christian
A1 - Kemnitz, Erhard
A1 - Resch-Genger, Ute
T1 - Dopant ion concentration-dependent upconversion luminescence of cubic SrF2:Yb3+, Er3+ nanocrystals prepared by a fluorolytic sol–gel method
N2 - A fluorolytic sol–gel method was used for the fast and simple synthesis of small cubic-phase SrF2:Yb3+, Er3+ upconversion (UC) nanocrystals (UCNC) of different composition at room temperature. Systematic studies of the crystal phase and particle size of this Yb3+,Er3+-concentration series as well as excitation power density (P)-dependent UC luminescence (UCL) spectra, UCL quantum yields (ΦUCL), and UCL decay kinetics yielded maximum UCL performance for doping amounts of Yb3+ of 13.5% and Er3+ of 1.3% in the studied doping and P-range (30–400 W cm−2). Furthermore, ΦUCL were determined to be similar to popular β-NaYF4:Yb3+,Er3+. The relative spectral UCL distributions revealed that all UCNC show a strong red emission in the studied doping and P-range (30–400 W cm−2) and suggest that the UCL quenching pathway for unshelled cubic-phase SrF2:Yb3+,Er3+ UCNC differs from the commonly accepted population and depopulation pathways of β-NaYF4:Yb3+,Er3+ UCNC. In SrF2:Yb3+,Er3+ UCNC the 4S3/2 →
4I13/2 transition exhibits a notably stronger sensitivity towards P and reveals increasing values for decreasing Yb3+–Yb3+ distances while the 4I9/2 → 4I15/2 transition is significantly less affected by P and energy migration facilitated UCL quenching. These results emphasize the complexity of the UC processes and the decisive role of the crystal phase and symmetry of the host lattice on the operative UCL quenching mechanism in addition to surface effects. Moreover, the room temperature UCNC synthesis enabled a systematic investigation of the influence of the calcination temperature on the crystal phase of powder-UCNC and the associated UCL properties. Calcination studies of solid UCNC of optimized doping concentration in the temperature range of 175 °C and 800 °C showed the beneficial influence of temperature-
induced healing of crystal defects on UCL and the onset of a phase separation connected with the oxygenation of the lanthanide ions at elevated temperature. This further emphasizes the sensitivity of the UC process to the crystal phase and quality of the host matrix.
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photophysics
KW - Synthesis
PY - 2022
DO - https://doi.org/10.1039/d2nr02337g
SP - 1
EP - 10
PB - Royal Society of Chemistry
AN - OPUS4-55364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Pauli, J.
A1 - Güttler, Arne
A1 - Richter, Maria
A1 - Fiedler, Saskia
A1 - Frenzel, Florian
A1 - Wegner, Karl David
A1 - Würth, Christian
T1 - Photoluminescence Quantum Yields of Luminescent Nanocrystals and Particles in the UV/vis/NIR/SWIR
N2 - The rational design of functional luminescent materials such as semiconductor quantum dots and lanthanide-based upconversion nanoparticles, all photophysical and mechanistic studies, and the comparison of different emitters require accurate and quantitative photoluminescence measurements. Particularly the reliable determination of the key performance parameter photoluminescence quantum yield (f), the number of emitted per absorbed photons, and the brightness are of special importance for luminescence applications in the life and material sciences and nano(bio)photonics.[1] In this context, examples for absolute measurements of the photoluminescence quantum yields of UV/vis/NIR/SWIR emissive semiconductor quantum dots and rods, made from different materials, and spectrally shifting lanthanide upconversion nanocrystals with different surface chemistries in transparent matrices are presented including excitation wavelength and power density dependent studies utilizing integration sphere spectroscopy.[2,3] In addition, procedures for the absolute determination of the photoluminescence quantum yields of scattering dispersions of larger size quantum rods and differently sized inorganic particles have been developed as well as procedures for the characterization of solid luminescent nanomaterials such as different perovskites and YAG:Cer converter materials.[4] Thereby, challenges and pitfalls of f measurements in different wavelength regions including the SWIR and material-specific effects related to certain emitter classes are addressed, achievable uncertainties are quantified, and relative and absolute measurements of photoluminescence quantum yield measurements are compared to underline limitations of the former approach. Finally, a set of novel UV/vis/NIR quantum yield standards is presented including their certification with a complete uncertainty budget.[5]
T2 - NANAX 10
CY - Klosterneuburg, Austria
DA - 03.07.2023
KW - Fluorescence
KW - Optical spectroscopy
KW - Reference data
KW - Traceability
KW - NIR
KW - Scattering
KW - Reference material
KW - Certification
KW - Quality assurance
KW - Dye
KW - Reference product
KW - SWIR
KW - Nano
KW - Particle
KW - Perovskite
KW - Integrating sphere spectroscopy
KW - Quantum yield
PY - 2023
AN - OPUS4-58238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - A Multimodal Approach to Quantify Surface Functional Groups and Ligands on Amorphous Silica Nanoparticles
N2 - Nowadays amorphous silica nanoparticles (SiO2-NP) are one of the most abundant engineered nanomaterials, that are highly stable and can be easily produced on a large scale at low cost. Surface functionalized SiO2-NP are of great interest in the life and material sciences, as they can be used e.g. as
drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. Their performance in such applications depends not only on particle size, size distribution, and morphology, but also on surface chemistry, i.e. the total number of surface functional groups (FG)
and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG and ligands, we investigated and compared various analytical methods commonly used for FG quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance and thermal analysis methods.
The potential of our multimodal approach for FG quantification was demonstrated for commercial and custom-made silica particles of varying FG, showing not only an influence of the synthesis methods on the number of FG but also on the performance. In the future, our strategy can contribute to establish multi-method characterization strategies to provide a more detailed picture of the structure-properties relationship.
T2 - Advanced Materials Safety 2023
CY - Saarbrücken, Germany
DA - 08.11.2023
KW - Amorphous silica particles
KW - Surface group analysis
KW - Ligands
KW - Reference material
KW - Optical spectroscopy
KW - Quantitative NMR
KW - Optical assays
KW - Titration
KW - Engineered nanomaterials
KW - Advanced Materials
PY - 2023
AN - OPUS4-59124
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geißler, Daniel
T1 - Standardisation of concentration measurements of extracellular vesicles for medical diagnoses
N2 - Extracellular vesicles (EVs) are cell-derived particles in body fluids, which have excellent potential as next generation biomarkers for the early diagnosis of common diseases, such as cancer and thrombosis. This project aims to tap into the clinical potential of EVs by developing traceable measurements of number concentration, size distribution, refractive index (RI) and fluorescence intensity of cell-specific EVs in human blood and urine.
To realise our aims, we will develop synthetic reference materials with physical properties resembling EVs (WP1), instrumentation and procedures to standardise EV measurements in clinical laboratories (WP2), and ready-to-use biological test samples (WP3). These will then be evaluated in an inter-laboratory comparison study across a range (>20) of standard flow cytometers in clinical labs (WP4).
T2 - MetVesII M18 Interim Meeting
CY - Berlin, Germany
DA - 20.10.2020
KW - EMPIR 18HLT01 MetVesII
KW - Extracellular vesicles (EV)
KW - Flow cytometry (FCM)
KW - Reference materials
KW - Fluorescent particles
KW - Integrating sphere spectroscopy
PY - 2020
AN - OPUS4-51653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Quantification of the Total and Accessible Number of Functional Groups and Ligands on Nanomaterials
N2 - Surface-functionalized organic and inorganic nanoparticles (NP) are of great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. NP performance in such applications depends not only on particle size, size distribution, and morphology, but also on surface chemistry, i.e. the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. Methods for FG quantification should be simple, robust, reliable, fast, and inexpensive, and allow for the characteriza-tion of a broad variety of nanomaterials differing in size, chemical composition, and optical properties.
Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG such as amine, carboxy, thiol and aldehyde functionalities, we investigated and compared various analytical methods commonly used for functional group quantification. This includes electrochemical titration methods, dye-based optical assays, and other instrumental analytical techniques such as nuclear magnetic resonance, mass spectrometry, and thermal analysis methods.
T2 - Nanotech France
CY - Paris, France
DA - 15.06.2022
KW - Optical assays
KW - Functionalized nano- and microparticles
KW - Particle surface analysis
KW - Surface group quantification
KW - Terminal functional groups
PY - 2022
AN - OPUS4-55208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardization of Flourescence Measurements in the UV/VIS/NIR/IR at BAM
N2 - Photoluminescence techniques are amongst the most widely used tools in the life sciences, with new and exciting applications in medical diagnostics and molecular imaging continuously emerging. Advantages include their comparative ease of use, unique sensitivity, non-invasive character, and potential for multiplexing, remote sensing, and miniaturization. General drawbacks are, however, signals, that contain unwanted wavelength- and polarization contributions from instrument-dependent effects, which are also time-dependent due to aging of instrument-components, and difficulties to measure absolute fluorescence intensities. Moreover, scattering systems require special measurement geometries and the interest in new optical reporters with emission > 1000 nm strategies for reliable measurements in the second diagnostic for the comparison of material performance and the rational design of new fluorophores with improved properties.
Here, we present strategies to versatile method-adaptable liquid and solid fluorescence standards for different fluorescence parameters. Examples are multi-emitter glasses, spectral fluorescence standards, and quantum yield standards for the UV/vis/NIR.
T2 - Konsortiumtreffen Mikroskopie
CY - Universität Münster, Germany
DA - 20.01.2020
KW - Fluorescence standard
KW - Instrument calibration
KW - Integrating sphere spectroscopy
KW - Fluorescence quantum yield
KW - Fluorescent glasses
KW - Fluorescence microscopy
KW - Particle, imaging
PY - 2020
AN - OPUS4-50308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Walter, Tina
T1 - Does multispectral optical tomography add value in recognizing process deviations in the PBF-LB/M process?
N2 - Die Qualitätssicherung im Laserstrahlschmelzen metallischer Pulver (PBF-LB/M) stellt eine zentrale Herausforderung für die industrielle Anwendung additiver Fertigungsverfahren dar. Insbesondere die frühzeitige Vorhersage von Defekten, wie z.B. Porositäten, ist entscheidend für die Prozessstabilität und resultierende Bauteilqualität. In diesem Beitrag wird ein neuartiger Ansatz, die multispektrale optische Tomografie (MS-OT), vorgestellt und erste Forschungsergebnisse hinsichtlich der Defekterkennung präsentiert.
T2 - Promotionsretreat 2025
CY - Würzburg, Germany
DA - 10.03.2025
KW - AM
KW - Additive Fertigung
KW - Process Monitoring
KW - Optische Tomografie
PY - 2025
AN - OPUS4-64988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Nanoparticle Characterisation - The long way to standardisation
N2 - Diese Präsentation gibt einen Überblick über die Entwicklung der Nanopartikelforschung von ca. 2005 bis heute. Beginnend mit den Besonderheiten von Nanopartikeln und der Aufnahme in den menschlichen Körper über Messmethoden bis hin zur Entwicklung einer Prüfrichtlinie im Rahmen der OECD und einem Ausblick über die absehbaren digitalen Entwicklungen.
T2 - Abteilungsseminar der Abteilung 4
CY - Berlin, Germany
DA - 27.02.2025
KW - Nanomaterials
KW - Nano
KW - OECD
KW - Standardisierung
KW - Advanced Materials
PY - 2025
AN - OPUS4-64977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Walter, Tina
T1 - Multispektrale optische Tomografie (MK-OT) trifft MachineLearning
N2 - Das pulverbettbasierte Laserstrahlschmelzen von Metallen (PBF-LB/M) zählt zu den am weitesten verbreiteten additiven Fertigungsverfahren für metallische Bauteile. Trotz zunehmender industrieller Relevanz, etwa in Luft- und Raumfahrt, Medizintechnik und Energieanwendungen, bleibt eine umfassende Prozessüberwachung und Qualitätssicherung eine zentrale Herausforderung. Die hohe Komplexität des Verfahrens, bedingt durch eine Vielzahl interagierender Prozessparameter, sowie die resultierende Datenfülle erschweren die direkte Korrelation zwischen Prozessanomalien und resultierenden Bauteildefekten wie Poren oder Rissen.
Zahlreiche Monitoring Ansätze, insbesondere thermografische Verfahren, wurden bereits intensiv untersucht. Dennoch fehlt es bislang an praxistauglichen, wirtschaftlich skalierbaren Lösungen. Insbesondere die Kosten und begrenzte Sichtfelder vieler Systeme hemmen eine breite industrielle Anwendung.
Oster et al. [1] konnten zeigen, dass die Analyse kurzwelliger Infrarotstrahlung (SWIR-Thermografie) mittels auf künstlicher Intelligenz (KI) basierender Auswertung zur ortsaufgelösten Detektion von Porosität im PBF-LB/M-Prozess geeignet ist. Ihr Ansatz erlaubt erstmals die Identifikation nicht gezielt induzierter Poren, zeigt jedoch Einschränkungen hinsichtlich des erfassten Sichtfelds (~9 × 10 mm²) und der Systemkosten (~30k€).
Eine vielversprechende Alternative stellt die Multikanal Optische Tomografie (MK-OT) dar [2], die auf kostengünstigen visuellen Kameras basiert. Durch gleichzeitige Erfassung mehrerer Spektralbereiche lassen sich Schichtbilder mit hoher räumlicher Auflösung und verbesserter Robustheit, verglichen mit marktüblicher monospektralen OT, gegenüber prozessbedingten Schwankungen erzeugen [2]. Die auch hierbei anfallenden großen Datenmengen erfordern eine automatisierte Auswertung. Bereits Ero et al. [3] und Feng et al. [4] konnten zeigen, dass mittels KI Porositätsvorhersagen aus herkömmlichen monochromatischen OT Daten gewonnen werden können.
Ziel dieses Beitrags ist es, das Vorgehen zur Untersuchung der Übertragbarkeit des in [1] vorgestellten KI-basierten Auswerteverfahrens auf das MK-OT-System vorzustellen. Hierdurch könnte eine kosteneffiziente und skalierbare Prozessüberwachung mittels Porositätsbestimmung für den industriellen Einsatz ermöglicht werden. Der aktuelle Stand der Arbeit und das geplante Vorgehen wird dargelegt.
T2 - CI-Workshop
CY - Berlin, Germany
DA - 20.11.2025
KW - AM
KW - Additive Fertigung
KW - Process Monitoring
KW - Optische Tomografie
PY - 2025
AN - OPUS4-64987
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - da Rocha, Morgana
A1 - Chaves, Eduardo
T1 - Assessment of Pd Nanoparticles as Chemical Modifiers and Preconcentration Agents for Cd Determination in River Water by HR-CS GFAAS
N2 - Cadmium is a heavy metal that can be hazardous to environmental and human health, even in trace levels.[1] In this way, the extraction and/or preconcentration of this element from environmental samples, such as river water, is important to obtain information about the composition and monitoring of potential contamination.[2] High-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) is widely used for Cd determination. However, the determination of this element at trace-level can be challenging, especially in complex matrices. Thus, nanoparticles (NPs) can be used as an alternative for the extraction and preconcentration of Cd in environmental samples, minimizing the potential interferences and improving the method´s limit of detection (LOD). Considering that Pd is also widely used as a “universal” chemical modifier, this project aims todevelop PdNPs capped with 3-mercaptopropionic acid (MPA) to assess its potential as a chemical modifier and preconcentration agent for Cd determination by HR-CS GF AAS in river water. In this way, the synthesis of PdNPs was performed in an aqueous medium by using ascorbic acid as a reducing agent. The characterization of PdNPs was performed by checking the size via dynamic light scattering (DLS), transmission electron microscopy (TEM), and inductively coupled plasma mass spectrometer in single particle mode (spICP-MS), where the median size was 56 ± 14 nm. The temperature program of HR-CS GFAAS was optimized for river water under three conditions: using Pd(NO3)2/Mg2+ (0.01%/0.5% m/v) as a chemical modifier (condition A), using Pd NPs as a chemical modifier (condition B), and without chemical modifiers (condition C). The pyrolysis and atomization temperatures for condition A were 900 and 1900 ºC, for condition B were 700 ºC and 1900 ºC, and for condition C were 500 and 1900ºC, respectively. Besides the temperature of pyrolysis for the universal chemical modifier being higher than that of PdNPs, using the PdNPs, the absorbance is significantly greater, according to the t-test for pairs, at a 95% confidence level. In addition, the evaluation of the preconcentration property of the PdNP was performed by adding 1 µg L-1 of Cd2+ in buffer pH 4 in two systems: one with and the other without PdNPs. After 1 h of stirring, both
systems were centrifuged at 3600 rpm for 10 min, and the absorbance in HR-CS GFAAS for Cd in both supernatants was evaluated. According to ANOVA from the t-test, at a 95% confidence level, there was a significant difference in the absorbance, indicating that Cd is interacting with the PdNPs. A multifactorial planning 2k, where k is the number of parameters of the extraction, which was time of extraction (10; 35; 60 min), Volume of Pd NPs (100; 300; 500 µL), pH (3; 5; 7), was used to evaluate the parameters with significant influence in the preconcentration of Cd2+. According to ANOVA, with 95% confidence, there is no lack of fit, and the parameters volume of PdNP and pH significantly influenced the response. In this way, the Doehlert methodology surface will be applied to both significant parameters. The goal is to achieve optimal conditions that increase the extraction efficiency of Cd2+ from environmental samples. The results indicate that the developed material is promising to use as a chemical modifier and for the preconcentration of Cd2+ in environmental samples.
T2 - 17th Rio Symposium on Atomic Spectrometry (RSAS 2025)
CY - Sao Pedro, Brazil
DA - 12.11.2025
KW - Pd Nanoparticles
KW - HR-CS GFAAS
KW - Cadmium Ion Sensing
KW - Particle Characterization
KW - Particle Surface
PY - 2025
AN - OPUS4-64997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Barik, Birendra Kumar
A1 - Chaurasia, Prashant Kumar
A1 - De, Amitava
T1 - Rapid estimation of temperature field and bead profile for wire arc directed energy deposition using an analytical heat conduction model
N2 - A prior estimation of the temperature field and bead profile can help fabricate dimensionally consistent and structurally sound parts using wire arc directed energy deposition (DED-Arc). We present here a three-dimensional analytical heat transfer model with a volumetric heat source to compute the transient temperature field and melt pool dimensions for DED-Arc. The analytical model considers the thermal conductivity and volumetric heat capacity as a linear function of temperature. In contrast to assuming a pre-defined deposited track profile, the same is scaled from the analytically computed melt pool dimensions into the substrate. The computed deposit profiles of single and multiple tracks and layers are validated extensively with the corresponding experimentally measured results for a range of DED-Arc process conditions.
KW - Additive manufacturing
KW - Analytical model
KW - Heat conduction analysis
KW - Volumetric heat source
KW - Deposit profile
PY - 2025
DO - https://doi.org/10.1177/13621718251398070
SN - 1362-1718
SP - 1
EP - 14
PB - SAGE Publications
AN - OPUS4-64836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eiby, Simon H. J.
A1 - Tobler, Dominique J.
A1 - Voigt, Laura
A1 - van Genuchten, Case M.
A1 - Bruns, Stefan
A1 - Jensen, Kirsten M. Ø.
A1 - Stawski, Tomasz M.
A1 - Wirth, Richard
A1 - Benning, Liane G.
A1 - Stipp, S. L. S.
A1 - Dideriksen, Knud
T1 - Topotactic Redox-Catalyzed Transformation of Iron Oxides
N2 - Fe oxides frequently exist in systems containing both Fe(II) and Fe(III), where their reactivity is enhanced and where interfacial electron transfer from Fe(II) adsorbed to the solids causes the transformation of metastable Fe oxides. Here, we contribute to the understanding of such a transformation using green rust sulfate (GR) synthesized in the presence or absence of Si or Al as the starting material. X-ray diffraction (XRD) and pair distribution function (PDF) analyses showed that (i) rapid oxidation by Cr(VI) caused transformation to Fe oxyhydroxide with short-range ordering, with a pattern identical to that reported for the oxidation of isolated GR hydroxide sheets (i.e., a trilayer of Fe with both edge- and corner-sharing polyhedra) and (ii) goethite formed at the expense of the short-range-ordered Fe oxyhydroxide when residual Fe(II) was present, particularly when Si was absent. This is consistent with the Fe(II)-catalyzed transformation of the short-range-ordered Fe oxyhydroxide. High-resolution transmission electron microscopy (TEM) showed that the two oxidation products coexisted within individual particles and that particle shape and the crystallographic orientation of both products were inherited from the original GR crystals, i.e., they had formed through topotactic transformation. We interpret that the structural reorganization to goethite occurred either in response to distortions caused by polaron movement or as a result of electron transfer reactions occurring at internal surfaces. Once nucleated, goethite growth can be sustained by dissolution–reprecipitation.
KW - Iron oxide
KW - Electron microscopy
KW - Pair distribution funvtion
KW - Total scattering
PY - 2025
DO - https://doi.org/10.1021/acsearthspacechem.5c00220
SN - 2472-3452
SP - 1
EP - 12
PB - American Chemical Society (ACS)
AN - OPUS4-64924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - SWIR luminescent nanomaterials – key chemical parameters for bright probes for in vivo bioimaging
N2 - A current challenge for studying physio-pathological phenomena and diseaserelated processes in living organisms with non-invasive optical bioimaging is the development of bright optical reporters that enable deep tissue penetration, a high detection sensitivity, and a high spatial and temporal resolution. The focus of this project are nanomaterials, which absorb and emit in the shortwave infrared (SWIR) between ~900–2500 nm where scattering, absorption, and autofluorescence of the tissue are strongly reduced compared to the visible and NIR.
T2 - QD2024 - 12th International Conference on Quantum Dots
CY - Munich, Germany
DA - 18.03.2024
KW - Quantum dots
KW - Advanced nanomaterials
KW - Fluorescence
KW - Quality assurance
KW - Gold nanocluster
KW - Shortwave infrared
KW - Spectroscopy
KW - Bioimaging
PY - 2024
AN - OPUS4-59783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Multivalent presentation of phenylpropenic acid amide inspired ligands by various nanoparticles and their potential use in anti-inflammatory therapy
N2 - Over the years, inflammation has become one of the most rapidly developing areas in medical research, due to new studies indicating its important role in chronical diseases, thrombosis and cancer. A promising target for anti-inflammatory therapy are the multistep adhesion process of leukocytes from the blood vessels into the inflamed tissue. and the numerous involved receptors and ligands. In particular, selectins and their respective carbohydrate ligands can inhibit this key step of the inflammation cascade. In previous work, it was shown that the multivalent presentation of highly negatively charged sulfated and carboxylated ligands on the particle surface can mimic natural selectin binders and increase the inhibition significantly.
Recent studies of the antioxidant and health promoting properties of cocoa, dark chocolate and red clover indicating potential anti-inflammatory properties of their clovamide-type phenylpropenoic acid amides, which are able to inhibit p-selectin expression and platelet-leukocyte interactions. Following the idea of small-molecule targeting drugs, we selected different epitopes and immobilized their sulfated derivatives onto different types nanoparticles, followed by a screening of their performance.
T2 - SALSA Make and Measure 2024: Interfaces
CY - Berlin, Germany
DA - 11.09.2024
KW - Gold colloids
KW - Surface group analysis
KW - Method
KW - Quantification
KW - Screening
KW - Nano
KW - Particle
KW - Synthesis
KW - Quality assurance
KW - Surface ligands
PY - 2024
AN - OPUS4-62159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fa, X.
A1 - Lin, Sh.
A1 - Yang, J.
A1 - Shen, Ch.
A1 - Liu, Y.
A1 - Gong, Y.
A1 - Qin, A.
A1 - Ou, Jun
A1 - Resch-Genger, Ute
T1 - −808 nm-activated Ca2+ doped up-conversion nanoparticles that release no inducing liver cancer cell (HepG2) apoptosis
N2 - Anear-infrared (NIR) light-triggered release method for nitric oxide (NO) was developed utilizing core/shell NaYF4: Tm/Yb/Ca@NaGdF4:Nd/Yb up-conversion nanoparticles (UCNPs) bearing a mesoporous silica (mSiO2) shell loaded with theNOdonor S-nitroso-N-acetyl-DL-penicillamine (SNAP). To avoid overheating in biological samples, Nd3+ was chosen as a sensitizer, Yb3+ ions as the bridging sensitizer, andTm3+ ions as UV-emissive activator while co-doping with Ca2+ was done to enhance the luminescence of the activatorTm3+.NOrelease from SNAP was triggered by an NIR-UV up-conversion process, initiated by 808nmlight absorbed by the Nd3+ ions.NOrelease was confirmed by the Griess method. Under 808nmirradiation, the viability of the liver cancer cell line HepG2 significantly decreased with increasing UCNPs@mSiO2-SNAP concentration. For a UCNPs@mSiO2-SNAP concentration of 200 μgml−1, the cell survival probability was 47%. These results demonstrate that UCNPs@mSiO2-SNAP can induce the release of apoptosis-inducingNOby NIR irradiation.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Excitation power density
KW - Brightness
KW - NIR
KW - Mechanism
KW - Triggered
KW - Release
KW - Cell
KW - PDT
KW - Dye
KW - Therapy
KW - Surface
KW - Coating
PY - 2022
DO - https://doi.org/10.1088/2050-6120/ac5524
VL - 10
IS - 2
SP - 1
EP - 9
PB - IOP Publishing
AN - OPUS4-54842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Quantification of surface functional groups on inorganic and organic nanomaterials using cleavable reporters
N2 - Engineered nanomaterials (NM) with their unique size-dependent properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing and electronics or food and consumer products. The performance and safety of NM are determined by the sum of their intrinsic physicochemical properties. Especially, the particle surface chemistry, which is largely controlled by the chemical nature and density of functional groups and ligands, is an important key driver for the performance, stability, and processibility of NM, as well as their interaction with the environment. Thus, methods for functional group quantification can foster the sustainable development of functional and safe(r) NM.
Aiming at the development of simple, versatile and multimodal tools for the quantification of common bioanalytically relevant functional groups, we designed a catch-and-release assay based on cleavable probes that enable the quantification of the cleaved-off reporters in the supernatant after particle separation. Thus, the approach circumvents interferences resulting from particle light scattering and sample-inherent absorption or emission. To study the potential of the assay, commercially available and in-house synthesized aminated and carboxylated polymer and silica nanoparticles of different functional group densities were tested.
Our cleavable probe strategy can be easily adapted to other analytical techniques requiring different reporters, or to different types of linkers that can be cleaved thermally, photochemically, or by variation of pH, utilizing well-established chemistry. In addition, it can contribute to the development of multi-method characterization strategies to provide a more detailed picture of the intrinsic physicochemical property - performance/safety relationships and thus can support the design of tailored nanomaterials with better controlled properties.
T2 - E-MRS Spring Meeting 2021 / ALTECH 2021 - Analytical techniques for precise characterization of nanomaterials
CY - Online meeting
DA - 31.05.2021
KW - Surface modified nano- and microparticles
KW - Optical assays
KW - Particle surface analysis
KW - Surface functional group quantification
PY - 2021
AN - OPUS4-55596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Srivastava, Priyanka
T1 - Multi-color nanosensors for ratiometric measurements of acidic, neutral, and basic pH based on silica and polystyrene particles
N2 - pH presents one of the most important analytes in the life and material sciences, indicating, e.g., diseases and corrosion processes. This includes the optical monitoring of pH in living cells for studying cellular internalization pathways, such as phagocytosis, endocytosis, and receptor mediated internalization with the aid of molecular and nanoscale fluorescent sensors. Nanoparticle (NP)-based sensors, that are labelled or stained with a multitude of sensor dyes, have several advantages as compared to conventional molecular probes like enhanced brightness, i.e., amplified signals, ease of designing ratiometric systems by combining analyte-sensitive and inert reference dyes, and increased photostability. Moreover, this can enable the use of hydrophobic dyes in aqueous environments. Versatile templates and carriers for the fabrication of nanosensors by staining and/or labelling with different fluorophores and sensor molecules are surface-functionalized particles like silica (SiO2) and polystyrene (PS) particles. Here we present a platform of blue-red-green fluorescent pH nanosensors for the measurement of acidic, neutral, and basic pH utilizing both types of matrices and two spectrally distinguishable sensor dyes with an integrated reference dye and demonstrate its applicability for cellular studies.
T2 - E-MRS Spring Meeting 2022
CY - Online meeting
DA - 30.05.2022
KW - Nanosensors
KW - pH sensing
KW - Silica- and polystyrene particles
KW - Ratiometric sensors
KW - Fluorescence
PY - 2022
AN - OPUS4-55597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
A1 - Lehmann Schlag, Jens
A1 - Burkert, Andreas
T1 - KorroPad®-Ein Kurzzeitprüfverfahren zur Qualitätssicherung der Oberflächen- und Schweißnahtnachbearbeitung nichtrostender Stähle
N2 - Die Ausbildung einer stabilen Passivschicht ist entscheidend für den Korrosionsschutz nichtrostender Stähle. KorroPad® bietet eine schnelle, zerstörungsfreie Bewertung der Passivschichtstabilität und ist seit 2025 als DIN 50024 genormt. Die Methode ermöglicht eine 15‑minütige Vor‑Ort‑Prüfung ohne Spezialwissen und schließt die Lücke zwischen teuren Laborverfahren und fehlender prozessbegleitender Qualitätssicherung. Der Beitrag beschreibt Funktionsprinzip, Anwendung sowie Beispiele aus der Oberflächen- und Schweißnahtbearbeitung.
T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025
CY - Dresden, Germany
DA - 26.11.2025
KW - KorroPad
KW - Nichtrostender Stahl
KW - Korrosion
KW - Passivität
PY - 2025
SN - 978-3-88355-454-9
VL - 43
SP - 1
EP - 7
PB - DGM Deutsche Gesellschaft für Materialkunde e.V.
CY - Sankt Augustin
AN - OPUS4-64933
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Thoralf
T1 - KorroPad®-Ein Kurzzeitprüfverfahren zur Qualitätssicherung der Oberflächen- und Schweißnahtnachbearbeitung nichtrostender Stähle
N2 - Die Ausbildung einer stabilen Passivschicht ist entscheidend für den Korrosionsschutz nichtrostender Stähle. KorroPad® bietet eine schnelle, zerstörungsfreie Bewertung der Passivschichtstabilität und ist seit 2025 als DIN 50024 genormt. Die Methode ermöglicht eine 15‑minütige Vor‑Ort‑Prüfung ohne Spezialwissen und schließt die Lücke zwischen teuren Laborverfahren und fehlender prozessbegleitender Qualitätssicherung. Der Beitrag beschreibt Funktionsprinzip, Anwendung sowie Beispiele aus der Oberflächen- und Schweißnahtbearbeitung
T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025
CY - Dresden, Germany
DA - 26.11.2025
KW - KorroPad
KW - Nichtrostender Stahl
KW - Korrosion
KW - Passivität
PY - 2025
AN - OPUS4-64930
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Vom Experiment zur semantischen Wissensrepräsentation: Datenstandards und Interoperabilität in der Materialcharakterisierung
N2 - Im Zeitalter der digitalen Transformation rückt die strukturierte Erfassung und semantische Verknüpfung von Materialcharakterisierungsdaten immer stärker in den Fokus, um eine effiziente Nutzung über Disziplin- und Projektgrenzen hinweg zu gewährleisten. Dabei bilden etablierte Datenstandards und semantische Technologien sowie Ontologien die Grundlage für eine nach FAIR-Kriterien aufgebaute Dateninfrastruktur, die sowohl maschinenlesbare als auch nachvollziehbare Wissensrepräsentationen ermöglicht.
In dieser Präsentation sollen Prinzipien interoperabler Datenarchitekturen erläutert werden, wobei auf die Bedeutung normkonformer Modelle und semantischer Konzeptualisierungen eingegangen wird. Dabei wird der steigende Bedarf an verlässlichen, reproduzierbaren und wiederverwendbaren Daten im Bereich der Materialwissenschaft und Werkstofftechnik adressiert, der insbesondere die Materialcharakterisierung und Werkstoffprüfung vor neue Herausforderungen stellt. Hinsichtlich der angestrebten Möglichkeiten zum erleichterten Datenaustausch kommen einheitlichen Datenformaten und -beschreibungen eine besondere Bedeutung zu.
Anhand ausgewählter Publikationen und Demonstratoren wird aufgezeigt, wie Ontologien als verbindende Zwischenschicht unterschiedliche Material- und Verfahrensdomänen konsistent abbilden und zusammenführen können.
Ein praktischer Anwendungsfall verdeutlicht die RDF-basierte Repräsentation von Zugversuchsdaten und deren Einbettung in ein Triple-Store-Datenbank-Umfeld. Hierbei fließen Erfahrungen aus der Entwicklung und Anwendung der PMD Core Ontology (PMDco) sowie normenkonformer Ontologien (z.B. Tensile Test Ontology, TTO) ein, welche im Rahmen des Projektes Plattform MaterialDigital (PMD, materialdigital.de) erstellt und betrachtet wurden. Darüber hinaus werden weitere methodische Ansätze und Entwicklungen aus diesem Projekt illustriert.
T2 - Tagung Werkstoffprüfung 2025
CY - Dresden, Germany
DA - 27.11.2025
KW - Wissensrepräsentation
KW - Ontologie
KW - Werkstoffprüfung
KW - Digitale Transformation
KW - Interoperabilität
PY - 2025
AN - OPUS4-64944
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Davila, Josue
T1 - Einfluss des initialen Pulveroxidationsgrads auf die prozessinduzierte Materialdegradation beim PBF-LB/M Prozess
N2 - Die vorliegende Studie untersucht den Einfluss unterschiedlicher Oxidationsgrade des im PBF-LB/M-Prozess verwendeten Ausgangspulvers auf dessen Degradation am Beispiel der Nickelbasis-Superlegierung Haynes 282. Zu diesem Zweck wurden vier Pulverbatches mit Sauerstoffgehalten zwischen etwa 140 ppm und 1400 ppm mittels PBF-LB/M verarbeitet. Zur gezielten Entnahme aufgeschmolzener Pulverpartikel aus wärmebeeinflussten Bereichen des Pulverbetts wurde ein spezieller Auffangbehälter konstruiert und mitgedruckt. Der Beschichtungs- und Schmelzprozess verlief störungsfrei. Bei höheren Oxidationsgraden wurde jedoch eine verstärkte Rauchentwicklung beobachtet, was erste Hinweise auf eine intensivere Spritzerbildung lieferte. Die Untersuchungen nach dem Bauprozess ergaben, dass insbesondere die feinen Partikelfraktionen infolge ihres hohen Oberflächen-zu-Volumen-Verhältnisses eine verstärkte Oxidation aufwiesen. Neben einer signifikanten Sauerstoffanreicherung konnten keine weiteren signifikanten Veränderungen der Hauptlegierungselemente in unaufgeschmolzenen Pulverpartikeln sowie in Spritzerpartikeln festgestellt werden. Darüber hinaus wurde bei stark oxidierten Pulvern eine signifikante Veränderung der Partikelgrößenverteilung beobachtet. Die gewonnenen Erkenntnisse leisten einen wichtigen Beitrag zum Verständnis oxidationsbedingter Degradationsmechanismen und bilden die Grundlage für die Optimierung von Strategien zur Wiederverwendung von Pulver im PBF-LB/M-Prozess, wodurch die Materialperformance gesichert werden kann.
T2 - DVM Tagung 2025 Additiv gefertigte Bauteile und Strukturen
CY - Berlin, Germany
DA - 04.11.2025
KW - Additive manufacturing
KW - Laser powder bed fusion (PBF-LB/M)
KW - Powder reuse
KW - Spatter particles
KW - Powder quality
KW - Particles ejected
KW - Recycling
KW - Powder degradation
KW - Powder oxidation
PY - 2025
AN - OPUS4-64953
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Davila, Josue
T1 - Influence Of Initial Powder Oxidation Level On Process-induced Material Degradation During The Laser Powder Bed Fusion Of Nickel-based Haynes 282
N2 - This study examines the impact of varying oxidation levels in nickel-based Haynes 282 powder on particle degradation during laser powder bed fusion (PBF-LB/M). Four powder batches with oxygen content levels of approximately from 140 ppm to1400 ppm were processed using PBF-LB/M. A powder collection container was fabricated to sample unmelted powder from heat-affected regions of the powder bed. Recoating and melting proceeded without issues; however, increased fume emissions were observed at higher oxidation levels, indicating intensified spatter formation. Post-process analysis revealed that finer particles exhibited greater surface oxidation due to their higher surface-to-volume ratio. Despite significant oxygen uptake, chemical analysis showed no measurable changes in key alloying elements in either the unmelted or spatter particles. Additionally, changes in particle size distribution became more pronounced at high oxidation levels. These findings provide a basis for understanding oxidation-driven degradation and optimizing powder reuse strategies to maintain material performance.
T2 - Euro Powder Metallurgy 2025 Congress & Exhibition
CY - Glasgow, Scotland
DA - 15.09.2025
KW - Additive manufacturing
KW - Laser powder bed fusion (PBF-LB/M)
KW - Powder quality
KW - Powder degradation
KW - Powder oxidation
KW - Spatter particles
KW - Particles ejected
KW - Powder reuse
PY - 2025
AN - OPUS4-64965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Davila, Josue
T1 - Parameter development for laser powder bed fusion of nickel-based Haynes 282 using diverse density determination methods
N2 - To manufacture functional components using laser powder bed fusion (PBF-LB/M), the execution of a parameter development with the specific material and machine is an indispensable step. Typically, in the search for the optimal parameter set, the volumetric energy density (VED) used to melt the material serves as an adjustment variable, while the resulting part density as the target parameter. Although this approach effectively reduces the process parameters search-space, additional criteria concerning part quality should be considered in the development. This paper introduces a systematic parameter selection approach, refining the characterization process for processing the nickel-based superalloy Haynes® 282®. The presented strategy not only incorporates the density as target condition but also considers the surface quality and dimensional accuracy of the manufactured samples, crucial for near-net-shape manufacturing. Additionally, three porosity measurement methods (Archimedes method, microscopy, gaspycnometry) for AM metal parts are compared, and their validity for this purpose is discussed.
T2 - LANE Conference 2024
CY - Fürth, Germany
DA - 14.09.2024
KW - Laser powder bed fusion (PBF-LB/M)
KW - Parameter development
KW - Gaspycnometry
KW - Density determination method
KW - Archimedes principle
KW - Surface quality
PY - 2024
AN - OPUS4-64966
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Fabry, Çağtay
A1 - Hirthammer, Volker
A1 - Scherer, Martin K.
T1 - weldx-widgets: advanced visualisation and jupyter widgets for weldx
N2 - This package provides advanced visualisation and interactive widgets for the weldx core package.
KW - Weldx
KW - Welding
KW - Research data
KW - Visualisation
PY - 2025
DO - https://doi.org/10.5281/zenodo.17790485
PB - Zenodo
CY - Geneva
AN - OPUS4-64973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Fabry, Çağtay
T1 - pytcs: a TwinCAT Scope text export file reader
N2 - A Python package for reading exported TwinCAT Scope Files. Export your TwinCAT Scope .svdx files to .txt/.csv and read them into Python.
KW - Python
KW - TwinCAT Scope
KW - File reader
KW - File format
KW - Measurement data
PY - 2025
DO - https://doi.org/10.5281/zenodo.17791125
PB - Zenodo
CY - Geneva
AN - OPUS4-64975
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Mechanical and thermal properties of aluminum titanate (AT)
N2 - In this seminar I present the microstructure and micromechanical properties of diesel particulate filter materials, and then particularize them to porous microcracked aluminum titanate.
I show that neutron diffraction is particularly suited for bulk studies, especially under applied load or at high temperatures. The combination of macroscopic and microscopic tests with modeling and simulation yields great added value to understand the mechanics of microcracking.
T2 - Webinar DFG Hotmix
CY - Online meeting
DA - 14.06.2021
KW - Imaging
KW - Neutron and X-ray Diffraction
KW - Non-linear stress-strain
KW - Anisotropy
KW - Microcracking
KW - Porosity
PY - 2021
AN - OPUS4-52838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalmbach, J.
A1 - Wang, Cui
A1 - You, Yi
A1 - Förster, C.
A1 - Schubert, H.
A1 - Heinze, K.
A1 - Resch-Genger, Ute
A1 - Seitz, M.
T1 - Near-IR to near-IR upconversion luminescence in molecular chromium ytterbium salts
N2 - Upconversion photoluminescence in hetero-oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex Ions was developed that exhibits excitation-power density-dependent cooperative sensitization of the chromium-centered 2E/2T1 phosphorescence at approximately 775 nm after excitation of the ytterbium band 2F7/2!2F5/2 at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric oxygen and can be observed in the presence of water molecules in the crystal lattice.
KW - Upconversion
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - Cr(III)
KW - Yb(III) complex
KW - Crystal
KW - Triplet-triplet annihilation
KW - Sensitization
KW - Light harvesting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512619
DO - https://doi.org/10.1002/anie.202007200
SN - 1433-7851
SN - 1521-3773
VL - 59
IS - 42
SP - 18804
EP - 18808
PB - Wiley
CY - Weinheim
AN - OPUS4-51261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Campos de Oliveira, Paula
T1 - Microstructural characterisation of aerospace ceramics via synchrotron X-ray computed tomography
N2 - This study investigates the microstructural evolution of refractory ceramics applied in aerospace using Synchrotron X-ray Computed Tomography (SXCT). We analyse how processing and temperature affect factors such as agglomeration, microcracking, particle orientation, and pore interconnectivity. These findings offer insights for optimising the design of more sustainable aircraft engines.
T2 - BESSY@HZB User Meeting 2024
CY - Berlin, Germany
DA - 11.12.2024
KW - Refractories
KW - Ceramics
KW - Synchrotron X-ray Computed Tomography
KW - Microstructural characterisation
KW - Aerospace
PY - 2024
AN - OPUS4-62390
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Roveda, Ilaria
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Synchrotron X-ray refraction detects microstructure and porosity evolution during in-situ heat treatments
N2 - For the first time, synchrotron X-ray refraction radiography (SXRR) has been paired with in-situ heat treatment to monitor microstructure and porosity evolution as a function of temperature. The investigated material was a laser powder bed fusion (LPBF) manufactured AlSi10Mg, where the initial eutectic Si network is known to disintegrate and spherodize into larger particles with increasing temperature. Such alloy is also prone to thermally induced porosity (TIP). We show that SXRR allows detecting the changes in the Si-phase morphology upon heating, while this is currently possible only using scanning electron microscopy. SXRR also allows observing the growth of pores, usually studied via X-ray computed tomography, but on much smaller fields-of-view. Our results show the great potential of in-situ SXRR as a tool to gain in-depth knowledge of the susceptibility of any material to thermally induced damage and/or microstructure evolution over statistically relevant volumes.
KW - Synchrotron X-ray refraction radiography
KW - Si network disintegration
KW - Thermally induced porosity (TIP)
KW - Laser powder bed fusion (LPBF)
KW - Statistically relevant volumes
KW - AlSi10Mg alloy
PY - 2022
DO - https://doi.org/10.1016/j.msea.2022.142732
SN - 0921-5093
VL - 838
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Morphological and crystallographic Anisotropy in porous ceramic
N2 - In this talk, the morphological (pore space) and crystallographic (domain) anisotropy of porous ceramics fordiesel particulate filter applications are discussed. The influence of such microstructural feature on the macroiscopic properties at componnt level is also shown.
T2 - MSCA Webinar
CY - Online meeting
DA - 05.12.2024
KW - Neutron Diffraction
KW - Porosity
KW - X-ray Computed Tomography
KW - X-ray refraction radiography
KW - Large Scale facilites
PY - 2024
AN - OPUS4-62047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Fernández, R.
A1 - Saliwan Neumann, Romeo
A1 - González-Doncel, G.
A1 - Bruno, Giovanni
T1 - Dislocation structures after creep in an Al-3.85 %Mg alloy studied using EBSD-KAM technique
N2 - The electron backscatter diffraction (EBSD) technique is used to investigate the dislocation structures formed after steady-state creep deformation of an Al-3.85%Mg alloy. This material is crept at two different stress levels, corresponding to the so-called power-law and power-law breakdown regimes. The results show that, regardless of the creep stress level, the strain tends to localize, leading to the formation of intragranular bands. The thickness of such bands is larger when the material is tested at loads corresponding to the power-law breakdown. This suggests enhanced diffusion by dislocation pipes.
KW - Steady-state creep
KW - Al-3.85%Mg alloy
KW - Power-law breakdown
KW - Electron backscatter diffraction (EBSD)
KW - Denoising filter
PY - 2023
DO - https://doi.org/10.1016/j.matlet.2023.133978
SN - 0167-577X
VL - 337
SP - 1
EP - 4
PB - Elsevier B.V.
AN - OPUS4-56941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Neutron Diffraction Based Residual Stress Analysis of Additively Manufactured Alloys
N2 - Additive manufacturing methods such as laser powder bed fusion offer an enormous flexibility in the efficient design of parts. In this process, a laser locally melts feedstock powder to build up a part layer-by-layer. It is this localized processing manner imposing large temperature gradients, resulting in the formation of internal stress and characteristic microstructures. Produced parts inherently contain high levels of residual stress accompanied by columnar grain growth and crystallographic texture. On a smaller scale, the microstructure is characterized by competitive cell-like solidification with micro segregation and dislocation entanglement. In this context, it is crucial to understand the interplay between microstructure, texture, and residual stress to take full advantage of the freedom in design. In fact, X-ray and neutron diffraction are considered as the benchmark for the non-destructive characterization of surface and bulk residual stress. The latter, characterized by a high penetration power in most engineering alloys, allows the use of diffraction angle close to 90°, enabling the employment of a nearly cubic gauge volume. However, the complex hierarchical microstructures produced by additive manufacturing present significant challenges towards the reliable characterization of residual stress by neutron diffraction. Since residual stress is not the direct quantity being measured, the peak shift imposed by the residual stress present in a material must be converted into a macroscopic stress. First, an appropriate lattice plane must be selected that is easily accessible (i.e., high multiplicity) and insensitive to micro strain accumulation. Second, a stress-free reference must be known to calculate a lattice strain, which can be difficult to define for the heterogeneous microstructures produced by additive manufacturing. Third, an appropriate set of diffraction elastic constants that relate the lattice strain to the macroscopic stress must be known. In this presentation, advancements in the field of residual stress analysis using neutron diffraction are presented on the example of the Ni-based superalloy Inconel 718. The effect of the complex microstructure on the determination of residual stress by neutron diffraction is presented. It is shown, how to deal with the determination of the stress-free reference. It is also shown that the selection of an appropriate set of diffraction elastic constants depends on the microstructure. Finally, the role of the crystallographic texture in the determination of the residual stress is shown.
T2 - Deutsche Neutronenstreutagung
CY - Aachen, Germany
DA - 16.09.2024
KW - Additive Manufacturing
KW - Neutron Diffraction
KW - Electron Backscatter Diffraction
KW - Laser Powder Bed Fusion
PY - 2024
AN - OPUS4-61476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pohl, P.
A1 - Serrano-Munoz, Itziar
A1 - Markötter, Henning
A1 - Göken, Mathias
A1 - Höppel, H. W.
T1 - Toughening mechanisms and enhanced damage tolerant fatigue behaviour in laminated metal composites
N2 - In the present study, fatigue crack growth (FCG) in a laminated metal composite (LMC) consisting of Al-based constituents with dissimilar strength was studied. Additionally, the FCG in both monolithic constituent materials was determined and a linear elastic rule of mixture (ROM) concept was calculated as a reference for the FCG of the laminated composite. Crack networks in the laminates were analyzed post-mortem by means of light microscopy and synchrotron X-Ray tomography (SXCT). Significantly reduced FCG rates for the LMC were found at elevated stress intensity ranges compared to both the monolithic constituents as well as the ROM concept. This is the result of the formation of a complex 3D crack network in the laminated architecture caused by the appearance of the two different toughening mechanisms a) crack deflection and b) crack bifurcation at the vicinity of the interfaces.
T2 - Ninth International Conference on Low Cycle Fatigue
CY - Berlin, Germany
DA - 21.06.2022
KW - Laminated metal composite
KW - Damage tolerance
KW - Fatigue crack growth
KW - Toughening mechanism
KW - Synchrotron X-ray computed tomography
PY - 2022
DO - https://doi.org/10.48447/LCF9-2022-035
SP - 153
EP - 158
PB - DVM
AN - OPUS4-55231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
T1 - BAM activities in material characterization by advanced X-ray imaging
N2 - The overview of the activity of Federal Institute for Material Research and Testing (BAM, Belin, Germany) in the field of additively manufacturing material characterization will be presented. The research of our group is focused on the 3D imaging of AM materials by means of X-ray Computed Tomography at the lab and at synchrotron, and the residual stress characterization by diffraction (nondestructive technique). Also, two successful research project in collaboration with CAM2, Sweden are presented.
T2 - CAM2 Annual Meeting
CY - Gothenburg, Sweden
DA - 25.10.2023
KW - Additive manufacturing
KW - Residual stress
KW - X-ray computed tomography
PY - 2023
AN - OPUS4-58828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - In-situ imaging of additively manufactured alloys at the BAMline
N2 - In this work, we present the recent in-situ imaging developments at the BAMline (of synchrotron BESSY II, HZB), focused on the in-situ characterization and understanding of microstructural evolution of additively manufactured materials subjected to different environments. Two show cases are presented. In the first, X-ray refraction radiography (SXRR) was combined with in-situ heat treatment to monitor the microstructural evolution as a function of temperature in a laser powder bed fusion (LPBF) manufactured AlSi10Mg alloy. We show that SXRR allows detecting the changes in the Si-phase morphology upon heating using statistically relevant volumes. SXRR also allows observing the growth of pores (i.e., thermally induced porosity), usually studied via X-ray computed tomography (XCT), but using much smaller fields-of-view. In the second case study, XCT was combined with in-situ tensile test to investigate the damage mechanism in a LPBF Aluminum Metal Matrix Composite (MMC). In-situ SXCT test disclosed the critical role of the defects in the failure mechanism along with pre-cracks in the reinforcement phase of MMC. We found that cracks were initiated from lack-of-fusion defects and propagated through coalescence with other defects.
T2 - New Frontiers in Materials Design for Laser Additive Manufacturing
CY - Montabaur, Germany
DA - 22.05.22
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Synchrotron X-ray computed tomography
KW - Synchrotron X-ray Refraction
PY - 2022
AN - OPUS4-54900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - X-Ray absorption, refraction, and diffraction techniques for the characterization and non-destructive testing of materials
N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread equally holds for industrial and academic research and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated.
I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. Examples of micro-structured inhomogeneous materials will be given, such as Composites, Ceramics, Concrete, and Additively manufactured parts. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces.
Additionally, I will show how Neutron Diffraction, which is extremely well suited to the study of internal stresses, both residual and under external load, can well be coupled to the microstructural framework gained by CT, allowing understanding the microstructure-property relationships in materials.
T2 - VDI FA101- Anwendungsnahe zerstörungsfreie Werkstoff und Bauteilprüfung Jährliches Treffen
CY - Berlin, Germany
DA - 10.04.2025
KW - Neutron Diffraction
KW - X-ray computed tomography
KW - Large Scale Facilities
KW - X-ray refraction radiography
KW - BAMline
PY - 2025
AN - OPUS4-62939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Mehta, B.
A1 - Nyborg, L.
A1 - Virtanen, E.
A1 - Markötter, Henning
A1 - Hryha, E.
A1 - Bruno, Giovanni
T1 - Failure Mechanisms Investigation by Means of in-situ Synchrotron Computed Tomography in Aluminum MMC-based Alloy Tailored for Additive Manufacturing (AM)
N2 - The availability of high-performance Al alloys in AM is limited due to difficulties in printability, requiring both the development of synergetic material and AM process to mitigate problems such as solidification cracking during laser powder bed fusion (LPBF). The goal of this work was to investigate the failure mechanism in a LPBF 7017 Aluminium alloy + 3 wt% Zr + 0.5 wt% TiC. The processing leads to different categories of Zr-rich inclusions, precipitates and defects.
T2 - Alloys for Additive Manufacturing Symposium 2022 (AAMS22)
CY - Munich, Germany
DA - 11.09.2022
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Synchrotron X-ray computed tomography
KW - MMC
PY - 2022
AN - OPUS4-56110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - BAM Akademie 2023- Modul 2 Computertomographie
N2 - Hier werden die Grundprinzipien der Computertomographie dargestellt, die Artefakte, die bei den Messungen auftreten und die Datenanalysemethoden erklärt.
T2 - BAM Akademie - Webinar Reihe
CY - Berlin, Germany
DA - 05.10.2023
KW - Artefakte
KW - Auflösung
KW - Radon Transformation
KW - Rekonstruktion
KW - Metrologie
PY - 2023
AN - OPUS4-58509
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
A1 - Kupsch, Andreas
A1 - Serrano-Munoz, Itziar
T1 - Absorption and refraction tomography: Characterization and Non-destructive Testing of Micro-structured Materials
N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread holds equally for industrial and academic research, and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces.
T2 - MPA Seminar 2024
CY - Stuttgart, Germany
DA - 08.10.2024
KW - X-ray Refaction radiography
KW - X-ray computed tomography
KW - Damage
KW - Composites
KW - Large Scale facilites
KW - Synchrotron
PY - 2024
AN - OPUS4-61347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - X-ray refraction radiography. Case study: the thermal microcracking in ZrO2-SiO2 after application of external loads at high temperatures
N2 - This study is shown as an example of the potential of synchrotron X-ray refraction technique to determine the evolution of damage in brittle (microcracked) materials. The strength of X-ray refraction resides in its high detectability of features (e.g., cracks, pores) within large volumes, enabling a macroscopic characterization of the microstructure. The case study is a Zirconia-based cast refractory, which is aimed to function at high temperatures (even in excess of 1700°C) in industrial furnaces to enable the production of special glasses. Therefore, this material must withstand severe in-service conditions (both thermomechanical and chemical). X-ray refraction technique is used to monitor the microcracking evolution of the material, which was previously subjected to thermal cycles (crossing the martensitic phase transformation around 1000°C) at two different stress levels.
T2 - Euromat 2021
CY - Online meeting
DA - 13.09.2021
KW - Synchrotron refraction radiography
KW - Refractory zirconia
KW - Thermally induced microcracking
KW - Monoclinic to tetragonal transformation
PY - 2021
AN - OPUS4-53271
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Introduction to Residual Stress
N2 - The determination of residual stress in additively manufactured materials is a challenge, even after decades from the establishment of the basics of residual stress analysis. This is due to the peculiar microstructure of such materials. In fact, researchers have discovered that conventional methods for the determination of RS in materials do not properly work for AM materials. In this tutorial, the basics of RS analysis will be explained, together with the basics of AM manufacturing techniques. The microstructure of the peculiar materials (AM) dealt with here will be elucidated. Successively, the necessary modifications to the conventional approaches to RS analysis will be explained and case studies will be displayed, for the attendant to touch with hands the peculiarities of the approaches. Finally, a few experimental and theoretical tips will be given on dos and don’ts for a correct determination of RS in AM materials.
T2 - 11th European Conference on Residual Stresses (ECRS-11)
CY - Prague, Czech Republic
DA - 03.06.2024
KW - Neutron Diffraction
KW - Residual Stress
KW - Mechanical Properties
KW - X-ray diffraction
PY - 2024
AN - OPUS4-60422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Campos de Oliveira, Paula
T1 - Enhanced image segmentation of refractories using synchrotron X-ray computed tomography and machine learning techniques
N2 - The microstructure of refractory materials is complex, featuring a variety of mineral phases, agglomerates, defects, and controlled porosity. The behavior of refractories at high temperatures adds another layer of complexity, as phase transitions and particle rearrangements can strongly affect their properties. To analyze such intricate microstructure, advanced imaging techniques such as Synchrotron X-ray Computed Tomography (SXCT) allow detailed 3D visualization and quantification of features up to 1 μm. However, the intricacy of these microstructures makes phase identification (known as image segmentation) in digital images a challenging process. X-ray images often contain noise and image artifacts, making the analysis more difficult. Therefore, this work describes image segmentation and artifact reduction methods to characterize refractories using X- ray imaging. We studied refractory ceramics used in the aerospace industry, primarily composed of fused silica. For image segmentation, the traditional approach of greyscale thresholding was compared with machine learning. Greyscale thresholding relies on predefined algorithms to assign phases based on intensity values. In contrast, machine learning extracts patterns from large datasets, enabling more adaptive and accurate segmentation. By combining high-resolution SXCT and machine learning analysis algorithms, we successfully segmented previously uncharacterized 3D microstructural key features of refractories, including agglomerates, grain boundaries, pore size distribution and interconnectivity. Compared to traditional methods, the machine learning-enhanced segmentation presented a more accurate quantification of porosity and defects. The integration of advanced imaging techniques with machine learning segmentation significantly improves the characterization of refractory materials, providing a more precise understanding of the relationship between microstructure and material performance, supporting the development of innovative industrial solutions.
T2 - 19th Biennial Unified International Technical Conference on Refractories (UNITECR 2025)
CY - Cancún, Mexico
DA - 27.10.2025
KW - Synchrotron X-ray Tomography
KW - Refractories
KW - Machine learning
KW - Ceramics
KW - Aerospace
PY - 2025
AN - OPUS4-64612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
A1 - Jaenisch, Gerd-Rüdiger
A1 - Bellon, Carsten
A1 - Jaczinski, Jessica
T1 - Virtual XCT - Simulation of Industrial XCT-Systems with aRTist
N2 - One of the few 3D methods, that can be used to analyze an object non-destructively, is X-ray computed tomography (CT). The determination of the object's deviations, such as shape and the internal structure of objects, including defects and material degradation, is of particular interest to industry. The ability of CT to scan an object with its internal and external features at once causes increasing adoption in dimensional metrology. This includes the need to determine the measurement uncertainty.
Experimental uncertainty determination by conducting repeated CT measurements is costly and time-consuming. The simulation of the CT measurement process offers the possibility of determining the task-specific measurement uncertainty numerically in a resource-efficient manner.
There are already several software programs available that simulate CT systems, such as aRTist. Once the virtual replica of a CT system has been completed, it’s accuracy must be evaluated quantitively in comparison to the CT measurements. To focus on analyzing the quality of the simulated CT images different metrics are introduced for the comparison of experimental and simulated CT projections. The results of the comparisons are presented, and conclusions are drawn how to improve the simulation of industrial CT systems.
T2 - MPA Seminar 2024
CY - Stuttgart, Germany
DA - 08.10.2024
KW - X-ray Computed tomography
KW - Simulations
KW - Virtual XCT
KW - Digital Twin
PY - 2024
AN - OPUS4-61346
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Diffraction and Single-Crystal Elastic Constants of Laser Powder Bed Fused Inconel 718
N2 - Laser powder bed fusion (PBF-LB/M) of metallic alloys is a layer-wise additive manufacturing process that provides significant scope for more efficient designs of components, benefiting performance and weight, leading to efficiency improvements for various sectors of industry. However, to benefit from these design freedoms, knowledge of the high produced induced residual stress and mechanical property anisotropy associated with the unique microstructures is critical. X-ray and neutron diffraction are considered the benchmark for non-destructive characterization of surface and bulk internal residual stress. The latter, characterized by the high penetration power in most engineering alloys, allows for the use of a diffraction angle close to 90° enabling a near cubic sampling volume to be specified. However, the complex microstructures of columnar growth with inherent crystallographic texture typically produced during PBF-LB/M of metallics present significant challenges to the assumptions typically required for time efficient determination of residual stress. These challenges include the selection of an appropriate set of diffraction elastic constants and a representative lattice plane suitable for residual stress analysis. In this contribution, the selection of a suitable lattice plane family for residual stress analysis is explored. Furthermore, the determination of an appropriate set of diffraction and single-crystal elastic constants depending on the underlying microstructure is addressed.
In-situ loading experiments have been performed at the Swiss Spallation Neutron Source with the main scope to study the deformation behaviour of laser powder bed fused Inconel 718. Cylindrical tensile bars have been subjected to an increasing mechanical load. At pre-defined steps, neutron diffraction data has been collected. After reaching the yield limit, unloads have been performed to study the accumulation of intergranular strain among various lattice plane families.
T2 - 11th European Conference on Residual Stresses
CY - Prag, Czech Republic
DA - 03.06.2024
KW - Additive Manufacturing
KW - Laser Powder Bed fusion
KW - Diffraction Elastic Constants
KW - Microstructure
KW - Electron Backscatter Diffraction
PY - 2024
AN - OPUS4-60289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Diffraction and Single-Crystal Elastic Constants of Laser Powder Bed Fused Inconel 718
N2 - In this presentation, the results of the determination of the diffraction and single-crystal elastic constants of laser powder bed fused Inconel 718 are presented. The analysis is based on high-energy synchrotron diffraction experiments performed at the Deutsches Elektronen-Synchrotron. It is shown that the characteristic microstructure of laser powder bed fused Inconel 718 impacts the elastic anisotropy and therefore the diffraction and single-crystal elastic constants. Finally, the consequences on the diffraction-based residual stress determination of laser powder bed fused Inconel 718 are discussed.
T2 - AWT-Fachausschuss 13 "Eigenspannungen"
CY - Wolfsburg, Germany
DA - 19.03.2024
KW - Additive Manufacturing
KW - Laser Powder Bed fusion
KW - Diffraction
KW - In-Situ Testing
KW - Diffraction Elastic Constants
PY - 2024
AN - OPUS4-59900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - X-ray Computed Tomography: Facts and Myths
N2 - In this talk, I will describe the principle of Computed Tomography, explain its mathematical fundaments, show the artefacts occurring during data acquisition and give examples of applications.
T2 - Chalmers Annual Meeting 2024
CY - Gothenburg, Sweden
DA - 23.10.2024
KW - X-ray Computed tomography
KW - Defects
KW - Machine Learning
KW - Reconstruction
KW - Artefacts
KW - Synchrotron
PY - 2024
AN - OPUS4-61514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - RS analysis in laser powder bed fused austenitic stainless steel
N2 - The determination of residual stress in additively manufactured materials is a challenge, even after decades from the establishment of the basics of residual stress analysis. This is due to the peculiar microstructure of such materials. In fact, researchers have discovered that conventional methods for the determination of RS in materials do not properly work for AM materials. In this tutorial, the basics of RS analysis will be explained, together with the basics of AM manufacturing techniques. The microstructure of the peculiar materials (AM) dealt with here will be elucidated. Successively, the necessary modifications to the conventional approaches to RS analysis will be explained and case studies will be displayed, for the attendant to touch with hands the peculiarities of the approaches. Finally, a few experimental and theoretical tips will be given on dos and don’ts for a correct determination of RS in AM materials.
T2 - 11th edition of the European Conference on Residual Stress (ECRS11)
CY - Prague, Czech Republic
DA - 03.06.2024
KW - Residual stress
KW - Additive manufacturing
KW - Diffraction
KW - Laser Powder Bed Fusion
KW - AGIL
KW - 316L
PY - 2024
AN - OPUS4-60445
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Influence of Microstructure on the Diffraction-Based Residual Stress Determination in Laser Powder Bed Fused Inconel 718
N2 - Additive manufacturing processes such as laser powder bed fusion (PBF-LB) offer the ability to produce parts in a single manufacturing step. On the one hand, this manufacturing technique offers immense geometric freedom in part design due to its layer-by-layer manufacturing strategy. On the other hand, the localized melting and solidification impose the presence of large temperature gradients in the process. From a microstructural perspective, this inevitably results in micro-segregation and a columnar grain structure, often paired with a significant crystallographic texture. Even worse, these large temperature gradients can lead to internal stress-induced deformation or cracking during processing. At the very least, residual stress is retained in the final structures as a footprint of this internal stress. In this context, diffraction-based methods allow the non-destructive characterization of the residual stress field in a non-destructive fashion. However, the accuracy of these methods is directly related to the microstructural characteristics of the material of interest. First, diffraction-based methods access microscopic lattice strains. To relate these lattice strains to a macroscopic stress, so-called diffraction elastic constants must be known. The deformation behavior is directly linked to the microstructure. Therefore, the diffraction elastic constants also depend on the microstructure. Second, the presence of crystallographic texture should be considered in the residual stress determination, as variations in crystal orientations contribute differently to the diffraction signal.
Here we present the influence of the microstructure on the determination of residual stress by diffraction-based methods in as-built PBF-LB Inconel 718 parts. We obtained different microstructures by employing two different scanning strategies. In particular, different crystallographic textures were obtained by changing the relative angle of the scan vectors to the geometric axes of the part. The texture-based characterization of the residual stress field was carried out by surface, sub-surface, and bulk residual stress measurements. It was found that the residual stress determination significantly depends on the microstructure for strong crystallographic textures.
T2 - Material Science and Engineering Congress
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Additive Manufacturing
KW - Electron Backscatter Diffraction
KW - Microstructure
KW - Residual Stress
KW - X-ray Diffraction
PY - 2024
AN - OPUS4-61475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Capabilities at BAM, division 8.5- X-ray Imaging
N2 - The X-ray computed tomography capabilities at BAM (especially in Division 8.5) are shown. It is also shown that the group possesses X-ray refraction radiography techniques, which are complementary to absorption radiography, and uses diffraction for residual stress analysis. Examples of applications in the field of Additive Manufacturing ale also shown.
T2 - DGM AK XCT
CY - Berlin, Germany
DA - 27.11.2024
KW - X-ray Computed tomography
KW - Defects
KW - X-ray refraction radiography
KW - Additive Manufacturing
PY - 2024
AN - OPUS4-62046
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - Effect of heat treatment on residual stress in additively manufactured AlSi10Mg
N2 - Al-Si alloys produced by Laser Powder Bed Fusion (PBFLB) allow the fabrication of lightweight free-shape components. Due to the extremely heterogeneous cooling and heating, PBF-LB induces high magnitude residual stress (RS) and a fine Si microstructure. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their evolution in as-built state (AB) and after post-process heat treatments (HT). RS in single edge notch bending (SENB) subjected to different HT are investigated (HT1: 1h at 265°C and HT2: 2h at 300°C).
T2 - ESRF User Meeting 2023
CY - Grenoble, France
DA - 07.02.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Residual stress
PY - 2023
AN - OPUS4-56982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
T1 - Rissentwicklung in CFK-Laminaten nachgewiesen durch in situ Röntgen-Refraktion
N2 - In Leichtbauanwendungen sind Materialien mit geringen Dichten und hohen Festigkeiten gefragt. Insbesondere Faser-Kunststoff-Verbunde (FKV) erfüllen diese Anforderungen und werden zunehmend für Strukturbauteile eingesetzt. Die Oberflächen moderner Rotorblätter von Windkraftanlagen werden aus FKV gefertigt. Das Versagen dieser Materialien hat massiven Einfluss auf die Einsatzfähigkeit der gesamten Windkraftanlage. Daher ist die Kenntnis des Versagensverhaltens dieser Komponenten unter statischer und zyklischer Belastung von großem Interesse, um die Betriebsbeanspruchung abzuschätzen. Im Idealfall wird die Schadensentwicklung unter Betriebslast mit zerstörungsfreien in-situ-Prüfverfahren ermittelt. Hier berichten wir über die Beobachtung der Rissentwicklung in Carbon-Faserverstärkten Kunststoffen (CFK) unter kontinuierlicher Zugbelastung durch in-situ Synchrotron-Röntgenrefraktionsradiographie. Eine selbst entwickelte elektromechanische Zugprüfmaschine mit einem Kraftbereich bis zu 15 kN wurde in den Strahlengang an der BAMline (BESSY II) integriert. Da in herkömmlichen (Absorptions-) Radiographien Defekte wie Zwischenfaserbrüche oder Faser-Matrix-Enthaftung keinen ausreichenden Kontrast verursachen, wird zur Kontrastanhebung die Röntgenrefraktion benutzt. Hier wird das sogenannte Diffraction Enhanced Imaging (DEI) angewandt, um Primär- und gebrochene Strahlung mit Hilfe eines Analysatorkristalls zu trennen. Diese Technik ermöglicht schnelle Messungen mit einem Gesichtsfeld von einigen Quadratmillimetern (hier: 14 mm × 7.2 mm) und ist ideal für in-situ Untersuchungen. Die Bildgebung und der Zugversuch erfolgen mit einer Bildfrequenz von 0.7 / s und einer Dehnrate von 0.00055 / s . Bei 0°/90° Fasergelegen treten die ersten Zwischenfaserrisse bei 380 MPa (Dehnung 0.8 %) auf. Vor dem Versagen bei ca. 760 MPa (Dehnung 2.0 %) beobachten wir die Ausbildung eines nahezu äquidistanten Rissmusters (Risse in ca. 1 mm Abstand), das sich im geschädigten Zustand über die gesamte Probe erstreckt.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Röntgen-Refraktion
KW - Synchrotronstrahlung
KW - CFK
KW - Rissentwicklung
PY - 2023
AN - OPUS4-57622
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Numerical study of electric field distribution in breakdown strength testing of ceramics
N2 - Dielectric breakdown of insulators is a combined electrical, thermal, and mechanical failure. The exact breakdown mechanism in ceramics and the formulation of useful models are still subject of investigation. Recent studies highlighted that several experimental aspects of dielectric breakdown strength testing affect the test results, and thus impede the recognition of fundamental principles.
Excess field strength near the electrode can lead to premature breakdown in the insulating liquid. This would cause superficial damage to the test specimen and thus falsify the measurement results.
The field strength distribution is influenced by the ratio of permittivity of the sample and the surrounding insulating liquid. Premature breakdown depends on the breakdown strength of the liquid and the actual test voltage. The test voltage again depends on the specimen thickness.
To systematically investigate these relations, a numerical simulation study (FEM) of the electric field distribution in a typical testing rig with cylindrical electrodes was performed. The permittivity of the sample and the insulating liquid was parameterized, as well as the sample thickness. The electric field distribution was calculated for increasing test voltage. Field strength maxima are compared to experimental breakdown strength of typical insulating liquids and experimental breakdown locations on alumina. Strategies are discussed to adjust the insulation liquid and the sample thickness to reduce the influence of the testing setup on the dielectric breakdown strength results.
T2 - Ceramics in Europe 2022
CY - Krakow, Poland
DA - 10.07.2022
KW - Ceramics
KW - Dielectric breakdown strength
KW - Electric field distribution
KW - Alumina
PY - 2022
AN - OPUS4-55325
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zurcher, Theo
A1 - Serrano-Munoz, Itziar
A1 - Mishurova, Tatiana
A1 - Abreu Faria, Guilherme
A1 - Degener, Sebastian
A1 - Fridrici, Vincent
A1 - Charkaluk, Eric
A1 - Bruno, Giovanni
T1 - Sliding wear resistance and residual stresses of parts repaired by laser metal deposition
N2 - Large temperature gradients inherent to additive manufacturing (AM) processes induce large residual stress (RS) in the final part. Because RS can influence the tribological properties, this study focuses on the relationship between wear sliding properties and RS in IN718 coatings. Such coatings were deposited with a Laser metal deposition (LMD) machine using two different scanning strategies.
The wear resistance and RS state were investigated after surface milling. RS were measured before and after wear tests on a reciprocating sliding test apparatus.
Two different X-ray diffraction techniques were employed to measure the surface and subsurface state RS: Laboratory Energy Dispersive X-ray Diffraction (LEDXD) and Synchrotron X-ray Energy Dispersive Diffraction (SXEDD). Due to the milling process, the coatings show similar depth distributions of RS from 22 to 92 μm depth, but exhibit different magnitudes depending on the scanning strategy used. Reciprocating sliding wear tests induced high compressive residual stresses that erased the initial RS state, and a similar wear behavior was observed in the two samples. These samples possess similar texture and grain morphology. This demonstrates that the influence of RS on wear resistance is a second-order effect. Nevertheless, it was observed that RS can still impact the wear performance at the early testing stages of the repaired parts.
KW - Additive manufacturing
KW - Wear resistance
KW - Residual stress
PY - 2023
DO - https://doi.org/10.1007/s10853-023-09129-4
SN - 0022-2461
SP - 1
EP - 18
PB - Springer
AN - OPUS4-59084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
A1 - Fritsch, Tobias
A1 - Schröder, Jakob
A1 - Mishurova, Tatiana
A1 - Ulbricht, Alexander
A1 - Evans, Alexander
A1 - Serrano-Munoz, Itziar
T1 - How to experimentally determine residual stress in AM structures
N2 - The experimental determination of residual stress becomes more complicated with increasing complexity of the structures investigated. Unlike the conventional and most of the additive manufacturing (AM) fabrication techniques, laser powder bed fusion (PBF-LB) allows the production of complex structures without any additional manufacturing step. However, due to the extremely localized melting and solidification, internal stress-induced deformation and cracks are often observed. In the best case, significant residual stress is retained in the final structures as a footprint of the internal stress during manufacturing.
Here we report solutions to the most prevalent challenges when dealing with the diffraction-based determination of residual stress in AM structures, in particular the choice of the correct diffraction elastic constants. We show that for Nickel-based alloys, the diffraction elastic constants of AM material significantly deviate from their conventional counterparts. Furthermore, measurement strategies to overcome the hurdles appearing when applying diffraction-based techniques to complex-shaped lattice structures are presented: a) proper sample alignment within the beam, b) the proper determination of the residual stress field in a representative part of the structure (i.e., with an engineering meaning). Beyond the principal stress magnitude, the principal direcions of residual stress are discussed for different geometries and scan strategies, as they are relevent for failure criteria.
We show that the RS in the lattice struts can be considered to be uniaxial and to follow the orientation of the strut, while the RS in the lattice knots is more hydrostatic. Additionally, we show that strain measurements in at least seven independent directions are necessary for the correct estimation of the principal stress directions. The measurement directions should be chosen according to the sample geometry and to an informed choice on the possible strain field (i.e., reflecting the scan strategy).
We finally show that if the most prominent direction is not measured, the error in the calculated stress magnitude increases in such a manner that no reliable assessment of RS state can be made.
T2 - Additive 2024
CY - Berlin, Germany
DA - 12.06.2024
KW - Neutron Diffraction
KW - Residual Stress
KW - X-ray Computed Tomography
KW - Additive Manufacturing
KW - Lattice Structure
KW - Inconel
PY - 2024
AN - OPUS4-60423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Determingpeak tensile residual stresses in laser powder bed fusion using diffraction based analysis
N2 - Laser powder bed fusion (PBF-LB) metal additive manufacturing process is well known to generate large residual stresses in a range of alloys due to the complex and localized thermal cycles. In general, these residual stresses are considered deleterious during manufacturing and subsequent service operation. In several alloy classes including austenitic stainless steels and nickel alloys, tensile residual stresses are generated with magnitudes equal to the yield strength of the processed material depending on geometry and process parameters, which can be located at surfaces/subsurface of a built structure. Knowledge of the magnitude and location of these peak tensile residual stresses is crucial for optimizing in-process or post process mitigation strategies, validating process models, and for consideration in structural integrity assessments. Several diffraction-based approaches have been demonstrated to characterize the magnitude and location of the maximum tensile residual stresses. These approaches include laboratory X-ray diffraction with electrolytic layer removal, energy dispersive synchrotron diffraction and neutron diffraction onPBF-LB prisms of several alloys, resolving the position and magnitude of the peak tensile residual stress. This work provides important considerations when determining these peak tensile residual stresses in newly developed alloys,novel processing strategies and when using more standard residual stress analysis methods.
T2 - Alloys for Additive Manufacturing (AAMS) 2025
CY - Neuchâtel, Switzerland
DA - 03.09.2025
KW - Residual stress
KW - Diffraction
KW - AGIL
KW - Laser powder bed fusion
KW - MANUFACT
PY - 2025
AN - OPUS4-64134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Röntgen Bildgebende Absorptions- und Refraktionsverfahren zur Charakterisierung keramischer Werkstoffe
N2 - Wir präsentieren Labor- und Synchrotron-Röntgenrefraktionstechniken, wie sie an der BAM implementiert sind.
Wir zeigen, dass die Labor-Röntgenrefraktionstopographie (XRRT) und die Synchrotron-Röntgenrefraktionsradiographie (SRRR) außergewöhnliche Werkzeuge zur Untersuchung von Schädigungen und inneren Defekten (Poren, Mikrorisse) in leichten Materialien wie Keramiken und Kompositen sind. Tatsächlich nutzen diese Techniken den an Grenzflächen auftretenden Röntgenbrechungseffekt aus, um den Kontrast zwischen dem (schwach absorbierenden) Objekt und dem Hintergrund zu erhöhen. Dies ermöglicht die Erkennung sehr kleiner Objekte (sogar bis zu 1 nm Rissöffnung) und die Quantifizierung ihrer spezifischen Oberfläche, die mit ihrem Einfluss auf die Materialeigenschaften korreliert. Wir zeigen die folgenden Anwendungen: a) Quantifizierung der Faserentbindung in laminaten Epoxid-Kohlenstoff-Verbundwerkstoffen; b) Mapping der Porengröße in gesinterten Keramiken; c) Eindringstiefe von Aschen in Keramikschutzschichten; d) Quantifizierung der Porenorientierung in Diesel Partikelfiltern; e) 3D-Darstellung von Makrorissen und Faserentbindung in Verbundwerkstoffen auf Ti-Basis für Anwendungen in der Luft- und Raumfahrt (unter Verwendung von Röntgenrefraktionstomographie).
T2 - IAK Keramikbearbeitung
CY - Online meeting
DA - 22.10.2021
KW - Röntgenrefraktion
KW - Leichtbau
KW - Keramiken
KW - Poren
KW - Risse
PY - 2021
AN - OPUS4-54069
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Chaudhuri, Somsubhro
A1 - Pittner, Andreas
A1 - Winterkorn, Rene
A1 - de Finis, Rosa
A1 - Palumbo, Davide
A1 - Galietti, Umberto
T1 - Thermographic investigation of the anisotropic behaviour of additively manufactured AISI316 steel using DED-Arc
N2 - Additive manufacturing is one of the most promising techniques for industrial production and maintenance, but the specifics of the layered structure must be considered. The Direct Energy Deposition-Arc process enables relatively high deposition rates, which is favourable for larger components. For this study, specimens with different orientations were prepared from one AISI316 steel block – parallel and orthogonal to the deposition plane. Quasistatic tensile loading tests were carried out, monitored by an infrared camera. The obtained surface temperature maps revealed structural differences between both orientations. The consideration of surface temperature transients yields more details about the behaviour of the material under tensile loading than the conventional stress-strain-curve. These preliminary investigations were supplemented by thermographic fatigue trials. Although the anisotropy was also observed during fatigue loading the fatigue behaviour in general was the same, at least for both inspected specimens. The presented results demonstrate the abilities and the potential of thermographic techniques for tensile tests.
T2 - 17th Quantitative Infrared Thermography Conference
CY - Bologna, Italy
DA - 07.07.2025
KW - Thermoelastic effect
KW - Wire-arc-additive manufacturing
KW - thermal stress analysis
KW - fatigue testing
PY - 2026
DO - https://doi.org/10.21611/qirt-2024-029
SP - 1
EP - 8
AN - OPUS4-65372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fritsch, Tobias
T1 - 3D Analysis of Powder for Laser Beam Melting by Synchrotron X-ray CT
N2 - Additive Manufacturing (AM) in terms of laser powder-bed fusion (L-PBF) offers new prospects regarding the design of parts and enables therefore the production of complex structures. The quality of the feedstock material receives increasing attention, as it depicts the first part of the L-PBF process chain. The powder quality control in terms of flowability and powder bed packing density is therefore mandatory.
In this work, a workflow for quantitative 3D powder analysis in terms of particle size, particle shape, particle porosity, inter-particle distance and packing density was established. Synchrotron computed tomography (CT) was used to correlate the packing density with the particle size and particle shape for three different powder batches. The polydisperse particle size distribution (PSD) was transformed into a statistically equivalent bidisperse PSD. The ratio of the small and large particles helped to understand the powder particle packing density. While the particle shape had a neglectable influence, the particle size distribution was identified as major contributor for the packing density.
T2 - AM- Workshop BAM
CY - Online meeting
DA - 20.04.2021
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Powder
KW - Particle size distribution
KW - Packing density
PY - 2021
AN - OPUS4-53477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - Failure Mechanisms Investigation by Means of in-situ Synchrotron Computed Tomography in Aluminum MMC-based Alloy Tailored for Additive Manufacturing (AM)
N2 - Most of the Al alloys used in additive manufacturing (AM), in particular Laser Powder Bed Fusion (LPBF), do not exceed a strength of 200 MPa, whereas conventionally high-performance alloys exhibit strengths exceeding 400 MPa. The availability of such Al alloys in AM is limited due to difficulties in printability, requiring synergetic material and AM process development to satisfy harsh processing conditions during LPBF [1]. One approach is the addition of reinforcement to the based powder, allowing tailoring composition and properties of a Metal Matrix Composite (MMC) by AM. Still, the effect of the reinforcement on the resulting mechanical properties must be studied to understand the performance and limits of the newly developed material. The goal of this work was to investigate the failure mechanism of LPBF Al-based MMC material using in-situ Synchrotron X-ray Computed Tomography (SXCT) during mechanical testing.
T2 - International conference on tomography of material and structures
CY - Grenoble, France
DA - 27.06.2022
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Al alloy
KW - MMC
PY - 2022
AN - OPUS4-55228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Hennecke, M.
ED - Skrotzki, Birgit
T1 - Hütte Band 2: Grundlagen des Maschinenbaus und ergänzende Fächer für Ingenieure
N2 - Die HÜTTE ist ein Kompendium und Nachschlagewerk für unterschiedliche Aufgabenstellungen. Durch Kombination der Einzeldisziplinen dieses Wissenskreises kann das multidisziplinäre Grundwissen für die verschiedenen Technikbereiche und Ingenieuraufgaben zusammengestellt werden.
Die HÜTTE enthält in drei Bänden - orientiert am Stand von Wissenschaft und Technik und den Lehrplänen der Technischen Universitäten und Hochschulen - die Grundlagen des Ingenieurwissens.
Band 2 enthält die Grundlagen des Maschinenbaus und ergänzende Fächer.
KW - Grundlagen des Maschinenbaus
PY - 2022
SN - 978-3-662-64371-6
DO - https://doi.org/10.1007/978-3-662-64372-3
SN - 2522-8188
SP - 1
EP - 967
PB - Springer Vieweg
CY - Berlin
ET - 35
AN - OPUS4-55740
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison Report ISO/TC 229 for ISO/TC 202 and vice-versa
N2 - The liaison between the two ISO technical committees TC 229 Nanotechnologies and TC 202 Microbeam analysis, in both directions, is described in detail with highlight on the projects under developement since 2023 and which involve input/knowledge from ISO/TC 202.
T2 - 31st Plenary Meeting of ISO/TC202 Microbeam Analysis
CY - Tokio, Japan
DA - 29.10.2024
KW - ISO TC 202
KW - ISO TC 229
KW - Standardisation
KW - Nanotechnologies
KW - Microbeam analysis
PY - 2024
AN - OPUS4-61511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sachse, René
T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrO IrOxfilms revealed under realistic OER conditions
N2 - Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities.
We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques.
The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ε1 and imaginary part ε2), electrical and electronic properties such as resistivity (ρ) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (ε1) and imaginary part (ε2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER.
In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution at different potentials.
T2 - 54. Jahrestreffen deutscher Katalytiker
CY - Online meeting
DA - 16.03.2021
KW - Spectroscopic ellipsometry
KW - Electrocatalysis
KW - Oxygen evolution reaction
KW - Mesoporous iridium oxide films
KW - Non-destructive operando analysis
PY - 2021
AN - OPUS4-52928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Reliable, and reproducible physico-chemical data of nanomaterials for risk assessment
N2 - Nanoforms with at least one dimension below 100 nm have an important part to play in more and more areas of our daily life. Therefore, risk assessment of these materials is becoming increasingly important. In this context, the European Chemical Agency (ECHA) considered eleven physico-chemical properties as relevant, of which the following six are essential for the registration: chemical composition, crystallinity, particle size, particle shape, surface chemistry and specific surface area. Four of these priority properties can be obtained with electron microscopy and surface analytics like XPS and ToF-SIMS. The reliability of this data must be ensured, especially for their use for grouping and read across approaches. On the other hand, the “reproducibility” crisis has revealed major shortcomings in the reliability of published data.
In a case study, we show how the quality of the data can be ensured by using existing standards and protocols of each step in the workflow of sample characterization. As exemplary samples, two Al-coated TiO2 samples as nanopowders were selected from the JRC repository, capped either with a hydrophilic or a hydrophobic organic ultrathin shell. SEM results provided the size and shape of the nanoparticles, a first overview about the composition was obtained with EDS. XPS and ToF-SIMS supplied the surface chemistry, especially information about the shell and the coating of the particles. Standards and protocols of all steps of the analytical workflow including preparation and data reduction are discussed regarding reliable and reproducible data. Additionally, uncertainties for the different steps are specified.
Only such a detailed description of all these factors allows a comprehensive physico-chemical characterization of the nanoparticles with understanding of their potential risk assessment.
T2 - ECASIA 2022
CY - Limerick, Ireland
DA - 29.05.2022
KW - Reference data
KW - Risk assessment
KW - Nanomaterials
KW - Titania
PY - 2022
AN - OPUS4-54961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS TWA 37 - Quantitative Microstructural Analysis & Liaison with ISO/TC 202 Microbeam Analysis, Liaison with ISO
N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 46th Steering Committee Meeting
CY - Online meeting
DA - 08.09.2021
KW - VAMAS
KW - Nanoparticles
KW - Standardisation
KW - Inter-laboratory comparison
KW - ISO/TC 202
KW - ISO/TC 229
KW - ISO/TC 201
KW - Microstructure
KW - EBSD
PY - 2021
UR - http://www.vamas.org/twa/
AN - OPUS4-53237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - VAMAS ILC of functionalized Graphene by XPS and Graphene Oxide by SEM
N2 - The ideas of the planned VAMAS interlaboratory comparisons of functionalized graphene and graphene oxide are presented.
T2 - Stakeholder Advisory Board ISO-G-Scope
CY - Online meeting
DA - 12.01.2022
KW - Graphene
KW - XPS
KW - SEM
PY - 2022
AN - OPUS4-54375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
A1 - Fagan, J.
T1 - Contributors invited for two studies on concentration of bimodal silica nanoparticle and bipyramidal titania
N2 - International standardisation network VAMAS is calling for participants in two studies on the measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension and the measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension.
KW - Nanoparticles
KW - VAMAS
KW - Inter-laboratory comparison
KW - TiO2
KW - SiO2
PY - 2021
UR - https://www.iom3.org/resource/contributors-invited-for-two-studies-on-concentration-of-bimodal-silica-nanoparticle-and-bipyramidal-titania.html
SP - 1
EP - 2
PB - Institute of Materials, Minerals and Mining (IOM3)
CY - London, UK
AN - OPUS4-54410
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
T1 - BAM reference data - EDS raw data of Al-coated titania nanoparticles (JRCNM62001a and JRCNM62002a)
N2 - EDS spectra of Al-coated titania nanoparticles (JRCNM62001 and JRCNM62002a) provided by the JRC repository are provided.
KW - EDS
KW - Titania nanoparticles
KW - BAM reference data
PY - 2021
DO - https://doi.org/10.5281/zenodo.4986420
PB - Zenodo
CY - Geneva
AN - OPUS4-52833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bennet, Francesca
A1 - Hodoroaba, Vasile-Dan
T1 - BAM reference data - SEM raw data for the particles size distribution of Al-coated titania nanoparticles (JRCNM62001a and JRCNM62002a)
N2 - SEM raw images of Al-coated titania nanoparticles (JRCNM62001 and JRCNM62002a) provided by the JRC repository are provided together with the particle size distribution of the minimum Feret Diameter extracted from the given images.
KW - SEM
KW - Titania nanoparticles
KW - Particle size distribution
KW - BAM reference data
PY - 2021
DO - https://doi.org/10.5281/zenodo.5007367
PB - Zenodo
CY - Geneva
AN - OPUS4-52836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madbouly, Loay Akmal
T1 - Chemical Analysis of Functionalized Graphene along the Production Chain
N2 - Graphene has been commercialized for over a decade. It is usually used in the form of suspensions or inks. In this study, we analyze the starting material for commercial functionalized graphene (FG) solutions and inks as well as their starting material (FG powders) using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive X-Ray spectroscopy (EDX), time of flight secondary ion mass spectrometry (ToF-SIMS) and Auger electron spectroscopy (AES). Graphene was functionalized with fluorine, oxygen, ammonia, and carboxylic acid.
Our results suggest a significant effect of water and commercial resins on the presence as well as the morphological behavior of graphene and associated functionalized group. For example, XPS analysis shows some significant differences between the solutions and the starting materials (powders). These changes can be explained by the location of the functionalization at the outer most surface as indicated by Chemello et al.
T2 - MaterialsWeek 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Functionalized graphene
KW - Commercial graphene
KW - Graphene inks
PY - 2024
AN - OPUS4-60448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Morphological and chemical analysis of mesoporous mixed IrOx-TiOy thin films as electrode materials
N2 - Porous films play an important role particularly in energy applications like photovoltaics, electrolysis or batteries. Thin film properties such as thickness, chemical composition, crystallinity of the framework, and porosity define the activity of the porous films. The accurate morpho-chemical characterisation of mesoporous thin films is a challenging analytical task which requires the consideration of new analytical approaches based on the combination of data of different methods able to address the structure and chemical composition at the nanoscale. In this contribution we characterise thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with Energy-Dispersive X-ray Spectroscopy (EDS) at an SEM applied in a dedicated “thin film analysis” approach (1). Thus, the film mass deposition, film thickness and the film density can be determined. Further, by dividing the measured film density to an assumed (theoretical) metal oxide framework (skeletal) density, the thin film porosity can be extracted, too.
In order to assess the homogeneity of the thin film properties like the chemical composition, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Auger Electron Spectrometry are applied in the depth profiling mode, so that possible in-depth gradients are detected. Lateral inhomogeneities in the chemical composition and structure of the thin mesoporous films are also identified by applying the same methods in the line-scan or mapping mode, which can be further combined with in-depth sputtering for 3D information. The role of the spatial resolution of the analytical methods considered, which can go down well below 100 nm, will be highlighted.
T2 - 2024 Spring Meeting of the European Materials Research Society (E-MRS)
CY - Strasbourg, France
DA - 27.05.2024
KW - Mesoporous
KW - Thin films
KW - Iridium oxide
KW - Titanium oxide
KW - Thin film analysis
KW - Porosity
KW - SIMS
KW - Auger electron spectroscopy
PY - 2024
AN - OPUS4-60185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Chemical Nanoscale Analysis of Mesoporous Mixed IrOx-TiOx Thin Films
N2 - Porous films play an important role particularly in energy applications like photovoltaics, electrolysis or batteries. Thin film properties such as thickness, chemical composition, crystallinity of the framework, and porosity define the activity of the porous films. The accurate morpho-chemical characterisation of mesoporous thin films is a challenging analytical task which requires the consideration of new analytical approaches based on the combination of data of different methods able to address the structure and chemical composition at the nanoscale. In this contribution we characterise thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with Energy-Dispersive X-ray Spectroscopy (EDS) at an SEM applied in a dedicated “thin film analysis” approach. Thus, the film mass deposition, film thickness and the film density can be determined. Further, by dividing the measured film density to an assumed (theoretical) metal oxide framework (skeletal) density, the thin film porosity can be extracted, too.
In order to assess the homogeneity of the thin film properties like the chemical composition, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Auger Electron Spectrometry are applied in the depth profiling mode, so that possible in-depth gradients are detected. Lateral inhomogeneities in the chemical composition and structure of the thin mesoporous films are also identified by applying the same methods in the line-scan or mapping mode, which can be further combined with in-depth sputtering for 3D information. The role of the spatial resolution of the analytical methods considered, which can go down well below 100 nm, will be highlighted.
T2 - MaterialsWeek 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Thin films
KW - Mesoporous
KW - IR oxide
KW - Ti oxide
KW - Porosity
PY - 2024
AN - OPUS4-60452
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matthews, Lauren
T1 - Approaches to Surface Analysis of Modified Quartz Nanopipettes
N2 - Nanopipettes are a type of solid-state nanopore with needle-like geometry. Their applications range from imaging, sensing, diagnostics, and use as injectors. The response of nanopipette sensors is highly dependent on the size, geometry and chemical properties of the sensing region. As they are increasingly tuned and modified for specific analytes, a better understanding of the surface chemistry and morphology of the inner channel is necessary. With the aim of developing a comprehensive approach for characterisation of such nanopipettes, this research focuses on combining surface-sensitive analysis methods with advanced sample preparation techniques. Quartz substrates were modified by gas phase silanization, a well-utilised technique in the field to enhance performance of nanopipettes, and further functionalised with a metal bis thiolate complex, to aid in chemical analysis. The sample characterisation involved scanning electron microscopy (SEM), low-energy dispersive x-ray spectroscopy (EDX), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Auger electron spectroscopy (AES). Using focused ion beam (FIB) milling under gentle conditions, the inner surface of quartz nanopipettes was exposed whilst preserving the integrity of the overall structure (see figure). Owing to the challenging analysis conditions, modification and analysis of flat quartz substrates has been performed in parallel for optimisation purposes. The results demonstrate the first steps towards full characterisation of nanopipettes at the nanoscale, notably with access to the inner channel. The methods used here can be applied to gain further understanding of the response of these sensors to complex analytes and allow for the study of different surface functionalisations at the all-important sensing region.
T2 - European Conference on Applications of Surface and Interface Analysis (ECASIA 2024)
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Quartz nanopipettes
KW - Nanopipette modification
KW - Silanization
KW - Surface analysis
KW - Focussed ion beam
PY - 2024
AN - OPUS4-60447
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Graphene Flagship - Achievements and the way forward
N2 - The activities of the Graphene in the field of standardization will be summarized. The future activities of the Graphene Flagship CSA which was established recently will be presented with the focus on future challenges in standardization and regulation of graphene and other 2D materials.
T2 - Harmonisation & Standardisation of Test Methods for Nano- and Advanced Materials
CY - Online meeting
DA - 22.11.2023
KW - 2D materials
KW - Regulation
KW - Standardization
PY - 2023
UR - https://macrame-project.eu/macrame-meetings-workshops/ws_hamonisation_standardisation_2023/
AN - OPUS4-59497
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matthews, Lauren
T1 - Breaking the Wall of Rapid Diagnostics
N2 - In this short presentation the diagnostics, biomarkers and analysis are interrelated. The specificity and sensitivity of the DNA structures as well as the high-throughput option of the nanopore sensing are discussed.
T2 - Falling Walls Lab Berlin-Adlershof
CY - Berlin, Germany
DA - 21.09.2023
KW - Nanopipettes
KW - Sensing
KW - Diagnosis
KW - DNA structures
PY - 2023
AN - OPUS4-60450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Salzmann, Christoph
A1 - Pellegrino, Francesco
A1 - Hodoroaba, Vasile-Dan
T1 - STEM-in-SEM versus SE-InLens-type-SEM as a Reliable Analytical Pair-Tool for Measurement of Nanoparticle Size and Shape Distribution
N2 - Following points are addressed in this contribution: Advantages of correlative analysis in electron microscopy; Measurement principle of the different electron microscopy modes used; Presentation of the nanomaterials used for this study; Role of sample preparation; and, with particular description, the Sequence kV-variation with InLens SE & transmission SEM detection of the same field-of-view.
KW - Nanoparticles
KW - Electron microscopy
KW - Metrology
KW - Particle size distribution
PY - 2024
DO - https://doi.org/10.1093/mam/ozae044.308
VL - 30
IS - Supplement_1
SP - 650
EP - 651
PB - Oxford University Press (OUP)
AN - OPUS4-61042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Salzmann, Christoph
A1 - Heilmann, Maria
A1 - Pellegrino, Francesco
A1 - Durand, Bénédicte
A1 - Taché, Olivier
A1 - Zurutuza, Amaia
A1 - Hodoroaba, Vasile-Dan
T1 - Ongoing International Interlaboratory Comparisons on Size, Shape and (Relative) Concentration of Complex Nanoparticles under the Pre-Standardization Platform of VAMAS
N2 - An overview with the basics of size and shape measurement of particles and 2D structures according to established methodologies (and popular imaging processing software packages) with imaging techniques is given. Main descriptors are explained based on case studies with ongoing interlaboratory comparisons under the pre-standardisation platform of VAMAS.
KW - VAMAS
KW - Interlaboratory comparison
KW - Imaging
KW - Size distribution
KW - Particle concentration
KW - 2D materials
PY - 2024
DO - https://doi.org/10.1093/mam/ozae044.319
VL - 30
IS - Supplement 1
SP - 669
EP - 670
PB - Oxford University Press (OUP)
AN - OPUS4-61183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Report VAMAS/TWA 37 "Quantitative Microstructural Analysis" & Liaison with ISO/TC 202 "Microbeam Analysis"
N2 - The progress in activities on Quantitative MicroStructural Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 Microbeam Analysis is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing projects "Development of guidelines for reproducible TEM specimen preparation by FIB processing", "Measurement of dislocation density in metallic materials by Transmission Electron Microscope (TEM)", "Repeatability of high angular resolution electron backscatter diffraction (HR-EBSD) analysis for elastic strain measurements", and "Measurement of grain size and distribution of nanocrystalline nickel by using Transmission Kikuchi Diffraction (TKD) in SEM" are presented in detail.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 49th Steering Committee Meeting
CY - Rio de Janeiro, Brazil
DA - 23.09.2024
KW - VAMAS
KW - Interlaboratory comparison
KW - Microbeam Analysis
KW - FIB
KW - SEM
KW - TEM
KW - Sample preparation
PY - 2024
UR - www.vamas.org/twa37/index.html
AN - OPUS4-61388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - John, Elisabeth
T1 - Towards a high-entropy alloy thin-film reference material
N2 - Analyzing materials composed of multiple elements with spectroscopic techniques such as X-ray Photoelectron Spectroscopy (XPS), Auger-Electron Spectroscopy (AES) or Electron Probe Microanalysis (EPMA), can be challenging due to spectral overlap. Moreover, each analytical method introduces its own set of challenges, e.g., the strong secondary fluorescence effect for neighbor elements in EPMA, thus, making the accurate elemental quantification in such materials difficult. When the material is available as thin film, additional constraints are inherently present. To provide a reference material for these analytical challenges high entropy alloys (HEAs) are excellent candidates. Currently, there is no thin film reference available containing more than 2 elements.
Unlike traditional alloys, which typically consist of one or two main elements and smaller amounts of secondary elements, HEAs are characterized by the presence of multiple principal elements in almost equal proportions. This unique composition results in a high degree of disorder at the atomic level, leading to exceptional mechanical, physical, and often unexpected properties. HEAs have garnered significant attention in materials science and engineering due to their potential applications in a wide range of industries, from aerospace and automotive to electronics and renewable energy.
For the preparation of a dedicated thin film reference material, we have chosen to prepare HEAs by magnetron sputtering, since it is not associated with elemental segregation that may occur due to the high configurational entropy of HEAs, which promotes atomic rearrangements. Our goal was to prepare films with a homogeneous thickness and defined chemical composition to be analyzed by various methods dedicated to surface analysis.
The material, consisting of titanium, chromium, manganese, iron, and nickel was deposited as film on silicon substrates - to our knowledge the first HEA thin film of this type reported in literature. A set of different thickness of the films was chosen, on the one hand to facilitate the analysis with different techniques, and on the other side to evaluate the limitations of the respective methods. The films morphology was characterized as prepared by SEM followed by the analysis of their 2D compositional homogeneity by EDX, XRF, ToF-SIMS and XPS. in-depth chemical composition was evaluated by ToF-SIMS and AES. The outcomes of analyzing the initial batches of films will be presented.
T2 - European Conference on Applications Surface and Interface Analysis (ECASIA 2024)
CY - Gothenburg, Sweden
DA - 10.06.2024
KW - High-entropy alloy
KW - Thin film
KW - Magnetron sputtering
PY - 2024
AN - OPUS4-60455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schusterbauer, Robert
T1 - Correlative chemical imaging to reveal the nature of different commercial graphene materials
N2 - Since the original report in 2004 by Novoselov and Geim, Graphene gained incredible attention due to its fascinating properties. In the past 20 years, the synthesis and functionalization of graphene has evolved significantly[3]. Different synthesis techniques were developed which led to other graphenerelated materials such as graphene oxide (GO) or elemental-doped graphene. Further chemical functionalization can enhance but also alter or reduce specific properties of the graphene. To reveal the nature of these materials a proper physico‑chemical characterization with different analytical techniques is crucial.
Single-layer GO flakes kindly provided by Graphenea (Spain) were prepared for systematic image analysis. These flakes were disposed on an alignment-marked SiO2 substrate and correlatively imaged by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Raman spectroscopy. The high lateral resolution and/ or extreme surface sensitivity of the mentioned
techniques is necessary to explore monolayers. The ToF-SIMS images match well with the SEM and AFM images and provide information about the chemistry. With 2D Raman spectroscopy it is possible to differentiate between the number of stacked single-layer flakes. This is visualized in a 3D image (Figure b). Well-defined GO flakes could be used as a reference material for imaging of graphene-like structures but also of other types of 2D materials.
In addition to these monolayer GO flakes, commercial graphene-containing inks (Haydale) with a more complex morphology were also correlatively imaged. ToF-SIMS and SEM images were merged to identify the origin of different chemical fragments. The findings correlate closely with the expectation that the specific functionalizations (with fluorine and nitrogen as marker elements) are present only on the graphene flakes as presumed from the SEM images. Energy-dispersive X-ray spectroscopy (EDX) supports these results, yet with a much lower sensitivity compared to ToF-SIMS.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Correlative imaging
KW - ToF-SIMS
KW - SEM
KW - Graphene oxide flakes
KW - Raman
PY - 2024
AN - OPUS4-60680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Standardisation needs for regulatory testing of graphene and related 2D materials. phy-chem properties
N2 - The main properties and main methods which are needed for the physico-chemical characterisation of graphene related 2D materials are discussed. As expample for standardization, protocols for the measurement of the chemical composition with XPS are discussed. The results of an interlaboratory comparisons led to new recommendations for the reliable measurments protocols.
T2 - Materials Week 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Standardisation
KW - Functionalized graphene
KW - Interlaboratory comparison
KW - Endpoints
PY - 2024
AN - OPUS4-60537
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Advanced materials for the energy transition
N2 - The climate crisis is the burning issue of our time. In order to avert the impending consequences, global efforts are being made in a wide variety of social and scientific fields. This report looks at a small part of these efforts, a technical aspect, namely the question of which AdMa are currently considered in techniques to support the energy transition. AdMa, i.e. materials that are rationally designed to have new or enhanced properties, and/or targeted or enhanced structural features, are used in all sectors of the energy transition. Questions of energy generation, storage and saving are considered here. This report is based on literature research and contains a general compilation of various AdMa that are used in the energy transition or are being researched for this purpose. From this compilation, ten materials that are considered particularly relevant for various reasons were selected and examined in more detail in relation to their use. The specific question here lies in the conflicting objective that the development of technologies for the energy transition is welcomed, but the use of AdMa may entail possible challenges in view of chemical safety as well as sustainability and circular economy.
KW - Energy generation
KW - Energy saving
KW - Eneergy storage
KW - Energy transportation
PY - 2025
DO - https://doi.org/10.60810/openumwelt-7853
SN - 1862-4804
VL - 83
SP - 1
EP - 64
PB - Umweltbundesamt
CY - Dessau-Roßlau
AN - OPUS4-63529
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison between ISO/TC 202 Microbeam Analysis and VAMAS/TWA 37 Quantitative Microstructural Analysis
N2 - The liaison between ISO/TC 202 Microbeam Analysis and VAMAS/TWA 37 Quantitative Microstructural Analysis and other TWAs since the last Annual Meeting of ISO/TC 202 is reported. The VAMAS/TWA 37 projects initiated in the last year and the new ones in the planing phase are highlighted with technical and organisational details.
T2 - 31st Plenary Meeting of ISO/TC202 Microbeam Analysis
CY - Tokio, Japan
DA - 29.10.2024
KW - ISO TC 202
KW - Microbeam Analysis
KW - Interlaboratory comparison
KW - VAMAS
KW - Standardisation
PY - 2024
AN - OPUS4-61513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - John, Elisabeth
T1 - Exploring the SIMS Matrix Effect in High-Entropy Alloy Thin-Films
N2 - Compared with traditional alloys, which typically consist of one or two main elements and small amounts of secondary elements, High Entropy Alloys (HEA) are characterized by the presence of multiple principal elements in almost equal proportions. This unique composition results in a high degree of disorder at the atomic level, leading to exceptional mechanical, physical, and often unexpected properties. HEAs have garnered significant attention in materials science and engineering due to their potential applications in a wide range of industries, from aerospace and automotive to electronics and renewable energy.
Analyzing materials composed of multiple elements with spectroscopic techniques such as X-ray Photoelectron Spectroscopy (XPS), Auger-Electron Spectroscopy (AES) or Electron Probe Microanalysis (EPMA), can be challenging due to spectral overlap. This challenge reaches its peak if neighboring 3d elements are present, as it is the case for the famous Cantor alloy which is composed of Cr, Mn, Fe, Co and Ni. Moreover, each analytical method introduces its own set of challenges, e.g., the strong secondary fluorescence effect for neighbor elements in EPMA, thus, making the accurate elemental quantification in such materials difficult. If the material is available as thin film, additional constraints are inherently present. To provide a reference material for these analytical challenges HEAs are excellent candidates. Currently, there is no thin film reference available containing more than two elements.
Our goal is to prepare thin films with a homogeneous thickness and defined, homogenous chemical composition to be analyzed by various methods dedicated to surface analysis.
ToF-SIMS is an excellent method for the (3D) analysis of thin films, however due to the dependence of element ion yield on the surrounding chemical state i.e., the matrix effect, it is considered a non-quantitative method. In HEAs the elements are each present in a homogenous matrix which makes these materials interesting for investigation of the matrix effect. Moreover, we evaluate methods to minimize the disturbances of oxygen enhancement during the beginning of the sputter analysis and the effect of recoil mixing at the film/substrate interface with the aim to measure accurate depth profiles.
T2 - SIMS 24
CY - La Rochelle, France
DA - 09.09.2024
KW - High-entropy alloy
KW - ToF-SIMS
KW - Matrix Effect
PY - 2024
AN - OPUS4-62511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Challenges in Correlative imaging of Advanced Materials
N2 - Newly developed methodical approaches with an emphasis on correlative imaging analysis of morphology and chemistry of nanomaterials will be presented. Correlative imaging by high-resolution SEM with STEM-in-SEM as well as with EDS, and further with AFM, or with the new technique TKD (Transmission Kikuchi Diffraction) will be explained on various examples of nanostructures, both as starting materials and as embedded/functionalized nanoparticles in products. The unique analytical benefits of the Auger electron probe as a veritable nano-tool for the local surface chemistry will be highlighted. Examples of hybrid analysis of the bulk of nanomaterials by X-ray Spectroscopy and the highest surface-sensitive methods XPS and ToF-SIMS as advanced surface characterization methods available in the Competence Centre nano@BAM will be showed. Particularly for the spatially resolved analysis of the chemistry of nanostructures, such in-depth and lateral gradients of chemistry within mesoporous thin layers, or the completeness of the shells of core-shell nanoparticles, the latter methods are inherent.
Other dedicated developments like approaches for the quantitative determination of the porosity of thin mesoporous layers by electron probe microanalysis (EPMA) with SEM or the quantitative determination of the roughness of particle surface by high-resolution imaging with electron microscopy will be also presented.
T2 - Workshop: Harmonisation & Standardisation of Test Methods for Nano- and Advanced Materials
CY - Online meeting
DA - 18.11.2024
KW - Imaging
KW - Advanced materials
KW - Correlative imaging
KW - Nanomaterials
KW - Electron microscopy
KW - ToF-SIMS
PY - 2024
UR - https://macrame-project.eu/macrame-meetings-workshops/2nd-joint-online-workshop-harmonisation-standardisation-of-test-methods-for-nano-and-advanced-materials/
AN - OPUS4-61858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fernandez-Poulussen, D.
A1 - Hodoroaba, Vasile-Dan
T1 - Holistic, reliable and practical Characterization Framework for Graphene Family Materials, a correlated approach including Imaging based techniques
N2 - ACCORDs is an Horizon Europe project working in the development of an imaging-based characterization framework (ACCORDs framework) for the holistic correlative assessment of Graphene Family Materials (GFMs) as a representative of 2D nanomaterials (NMs) to assess and predict 2D NMs health and environmental risks. The ACCORDs framework will operationalise safe and sustainable by design (SSbD) strategies proposed in past or ongoing H2020 projects or within OECD by correlating low-, medium-, and high-resolution physico-chemical-biological imaging-based methods with non-imaging methods in a tiered approach. ACCORDs will deliver the ACCORDs framework and user guidance, new imaging-based characterisation methods, reference in vitro tests, new reference 2D NMs for different matrices, a new minimum information reporting guideline for FAIR data sharing and reuse of images as well as an atlas with reference images for diagnostics of compromised safety of GFMs/GFM products. The new guidelines and standard proposals will be submitted to standardisation bodies to allow creation of regulatory ready products. The novelty of ACCORDs is in translating the principles of medical imaging-based diagnostics to 2D material hazard diagnostics. ACCORDs will accelerate industrial sectors in the area of aviation, marine construction, drone production, flexible electronics, photovoltaics, photocatalytics and print inks-based sensors. The value ACCORDs proposes to the graphene industry are practical, easy, imaging-based tools for GFM quality monitoring next to the production line with a possibility to be correlated with advanced highresolution imaging characterization methods in case hazard i.e. deviation from controls (benchmark values) are diagnosed. The ACCORDs framework and tools will contribute to the European Green Deal by addressing the topic: “Graphene: Europe in the lead” and to a new European strategy on standardization, released on 2nd February, 2022
T2 - Joint Regulatory Risk Assessors Summit – Advancing Safety & Sustainability Assessments of Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - Graphene-related 2D materials (GR2M)
KW - Imaging
KW - SSbD
KW - ACCORDs
PY - 2025
UR - https://macrame-project.eu/macrame-meetings-workshops/jointrras/#Agenda
AN - OPUS4-63660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Investigation of Fe-Ni-O nanoparticles for water splitting
N2 - This study investigates the effect of varying iron-to-nickel ratios on the catalytic performance of Fe-Ni oxide nanoparticles (NPs) for the oxygen evolution reaction (OER). Addressing the issue of high energy wastage due to large overpotentials in OER, we synthesized and characterized different NP catalysts with different Fe: Ni oxide ratios. Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) were employed to determine the morphology, elemental and phase composition of the NPs. Furthermore, in-depth profiling with X-rayPhotoelectron Spectroscopy (XPS) and Hard X-ray Photoelectron Spectroscopy (HAXPES) revealedthat iron predominantly exists as oxide, while nickel exhibits both metallic and oxidic forms depending on the Fe content. XPS indicated an enrichment of iron at the NP surface, whereas HAXPES and EDSdata agreed on the bulk stoichiometry.
T2 - PhI European User Meeting 2025
CY - Eibelstadt, Germany
DA - 29.04.2025
KW - Oxygen evolution reaction
KW - In depth analysis
KW - (Hard) X-ray Photoelectron Spectroscopy
PY - 2025
AN - OPUS4-63334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Methodological Challenges and Gaps: Physico-Chemical Characterisation
N2 - The methodological challenges and gaps in the physico-chemical characterisation of graphene related 2D Materials (GR2M) are discussed. Solutions for filling the gaps are presented.
T2 - OECD Graphene Expert Workshop
CY - Paris, France
DA - 26.11.2024
KW - Graphene related 2D materials
KW - Structure activity relationsships
KW - Classification
PY - 2024
AN - OPUS4-61920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fagan, Jeffrey
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS TWA Nanoparticle Populations Projects 15 and 16
N2 - The progress in the VAMAS Project #15 "Measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension" within TWA 34 Nanoparticle Populations is presented with highlight of the following points:
- Determine and compare particle size and shape distribution by means of electron microscopy (SEM, TEM, STEM-in-SEM), atomic force microscopy (AFM) and small angle X-ray scattering (SAXS).
- Determine uncertainty induced by deposition protocol from liquid suspension with comparison to known values from a prior ILC with already deposited nanoparticles on TEM grids.
- Provide comparative validation of protocols for the techniques other than TEM.
Further, the VAMAS/TWA 34 Project #16 "Measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension" is presented. Follwowing points are discusssed:
- Validate the performance of imaging methods to measure the relative number concentration by electron microscopy (SEM, TEM) and atomic force microscopy (AFM) and two modes of bimodal (30 and 60 nm) silica nanoparticles
- Validate the performance of small angle X-ray scattering (SAXS) for the traceable measurement of the number concentration of the two modes.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 49th Steering Committee Meeting
CY - Rio de Janeiro, Brazil
DA - 23.09.2024
KW - VAMAS
KW - Nanoparticles
KW - Nanoparticle size and shape distribution
KW - Particle number concentration
KW - Interlaboratory comparison
KW - Standardisation
PY - 2024
UR - http://www.vamas.org/twa34/index.html
AN - OPUS4-61422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fagan, J.
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS TWA 34 Nanoparticle Populations Combined Projects P15 and P16
N2 - The progress in the VAMAS Project #15 "Measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension" within TWA 34 Nanoparticle Populations is presented with highlight of the following points:
- Determine and compare particle size and shape distribution by means of electron microscopy (SEM, TEM, STEM-in-SEM), atomic force microscopy (AFM) and small angle X-ray scattering (SAXS).
- Determine uncertainty induced by deposition protocol from liquid suspension with comparison to known values from a prior ILC with already deposited nanoparticles on TEM grids.
- Provide comparative validation of protocols for the techniques other than TEM.
Further, the VAMAS/TWA 34 Project #16 "Measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension" is presented. Follwowing points are discusssed:
- Validate the performance of imaging methods to measure the relative number concentration by electron microscopy (SEM, TEM) and atomic force microscopy (AFM) and two modes of bimodal (30 and 60 nm) silica nanoparticles
- Validate the performance of small angle X-ray scattering (SAXS) for the traceable measurement of the number concentration of the two modes.
- Discussion of sample preparation issues
- Publication of the results in 2026
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 50th Steering Committee Meeting
CY - London, United Kingdom
DA - 14.09.2025
KW - VAMAS
KW - Interlaboratory comparison
KW - Particle size and shape distribution
KW - Particle number concentration
KW - Standardisation
PY - 2025
UR - https://www.vamas.org/twa34/index.html
AN - OPUS4-64234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS Regional Report Advanced Materials Germany 2025
N2 - Regional standardisation activities and how VAMAS can help in any way to promote activities are reported. Activities related to organisational updates, government initiatives/priorities (especially related to Advanced Materials), details of any strategy documents publicly available, networks within Germany and how we engage are presented.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 50th Steering Committee Meeting
CY - London, United Kingdom
DA - 14.09.2025
KW - VAMAS
KW - Interlaboratory comparison
KW - Advanced materials
KW - Standardisation
PY - 2025
AN - OPUS4-64232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stockmann, Jörg Manfred
T1 - A new XPS test material for more reliable surface analysis of microstructures
N2 - Small-area XPS analysis is one of the most popular and powerful methods for analysing the surface of features in the micro-range. When measuring microstructures, the ques-tion arises whether the measuring point is really located at the point intended to be ana-lysed. Information in a measured spectrum might originate within the field of view (FoV) on the surface of the sample, from outside the FoV, or even from inherent contamination. To ensure that small structures can be measured correctly regardless of user and instru-ment, certain instrument and sample settings must be known and selected correctly: beam and aperture size as well as the aperture settings and the approximate dimensions of the structure to be analysed. This is the only way to ensure that the information in the spectrum originates only from the FoV on the analysed structure.
To test the performance of the XPS instruments, a dedicated test material was developed that consists of a gold surface on which 8 circles and 8 squares of chrome are incorpo-rated using a masking process, so that the Au substrate and the Cr structure surfaces are in the same surface plane. In order to be able to test as many as possible instruments from different manufacturers, the structures have been designed with a size ranging from 300 µm down to 7 µm. The layout of the test material has been optimised in regard of the handling. The structures are arranged along lines instead of a circumference, marking arrows around the smaller structures (≤50 µm) are added, and the lithography mask is optimised regarding edge and diffraction effects. Furthermore, the manufacturing process was changed from electron-beam deposition to mask lithography due to costs reasons. The structures on the test material were measured with a metrological SEM to determine their accurate dimensions and check the repeatability of the manufacturing process. XPS investigations with a Kratos AXIS Ultra DLD and an ULVAC-Phi Quantes demonstrates the suitability of this new test material for measuring the analysed area.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Small-area XPS
KW - Test material
KW - Field of view
KW - Imaging
PY - 2024
AN - OPUS4-60539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matthews, Lauren
T1 - Approaches to Surface Analysis of Modified Quartz Nanopipettes
N2 - Nanopipettes are a type of solid-state nanopore with needle-like geometry. Their applications range from imaging, sensing, diagnostics, and use as injectors. The response of nanopipette sensors is highly dependent on the size, geometry and chemical properties of the sensing region. As nanopipettes are increasingly tuned and modified for specific analytes, a better understanding of the surface chemistry and morphology of the inner channel is necessary. For exploring these effects, quartz nanopipettes were modified by gas phase silanization, a well-utilised technique in the field to enhance performance of nanopipettes, and further functionalised with a metal bis thiolate complex, to aid in chemical analysis. The inner channel of the sensing region was exposed with focused ion beam (FIB) milling as a dedicated sample preparation method for nanoscale surface analysis. The sample characterisation involved scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and low-energy energy dispersive x-ray spectroscopy (EDX). The results demonstrate the first steps towards full characterisation of nanopipettes at the nanoscale, notably with access to the inner channel. The methods used here can be applied to gain further understanding of the response of these sensors to complex analytes, and allow for the study of different surface functionalisation at the all-important sensing region.
T2 - 2024 Spring Meeting of the European Materials Research Society (E-MRS)
CY - Strasbourg, France
DA - 27.05.2024
KW - Nanopipettes
KW - FIB
KW - Surface analysis
KW - Surface modification
KW - Silanisation
PY - 2024
AN - OPUS4-60449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heilmann, Maria
A1 - Hodoroaba, Vasile-Dan
T1 - Project 16 Measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension
N2 - The progress of the VAMAS Project 16 "Measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension" in TWA 34 Nanoparticle Populations is presented. Follwowing points are discusssed:
- Validate the performance of imaging methods to measure the relative number concentration
• electron microscopy (SEM, TEM) and atomic force microscopy (AFM)
• two modes of bimodal (30 and 60 nm) silica nanoparticles
- Validate the performance of small angle X-ray scattering (SAXS) for the traceable measurement of the number concentration of the two modes.
T2 - VAMAS Regional Workshop 2023 - What can pre-normative research do for industry?
CY - Online meeting
DA - 24.01.2023
KW - Nanoparticles
KW - VAMAS
KW - Inter-laboratory comparison
KW - SiO2
KW - Electron microscopy
KW - AFM
PY - 2023
UR - https://www.bam.de/Content/EN/Events/2023/2023-01-24-vamas-regional-workshop.html
AN - OPUS4-57221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - del Giorgio, Elena
T1 - Visible and NIR emissive lanthanide(III) surfaces for new luminescent materials
N2 - Luminescent lanthanides(III) offer exceptional optical properties that can overcome issues often encountered with other fluorophores (e.g. organic dyes). Their long lifetimes up to milliseconds, low photobleaching and sharp and characteristic emission peaks make the lanthanides extremely valuable for the development of advanced luminescent materials. Previous work on Ru(II) and Ir(III) gold surfaces further highlights the potential of employing the luminescence of metal complexes for the fabrication of sensing platforms and devices.
Here, we incorporate visible and NIR-emitting lanthanide(III) complexes Ln2L3 (Ln = Eu(III), Nd(III), Yb(III)) to gold and plasmonic surfaces, translating the unique optical properties of the lanthanides(III) to practical devices. The Ln2L3 complexes are deposited on the surfaces with different methods, ranging from polymer aided physisorption to the covalent attachment on the gold surface. Furthermore, we exploit the high sensitivity to the coordination environment of lanthanides(III) to design and prepare a sensing platform.
T2 - 17th Conference on Methods and Applications in Fluorescence (MAF 2022)
CY - Göteborg, Sweden
DA - 11.09.2022
KW - Luminescent materials
KW - Lanthanide(III)
KW - Surface morphology
KW - AFM
KW - SEM/EDS
PY - 2022
UR - https://maf2022.com/
AN - OPUS4-56126
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Zapala, P.
A1 - Abel, Andreas
A1 - Michels, H.
A1 - Skrotzki, Birgit
T1 - Werkstoffanwendungen für Eisenaluminide (FeAl), (WAFEAL)
N2 - Die zunehmende geopolitische Bedeutung der Ressourcenverfügbarkeit sowie die Anforderungen an einen geschlossenen Materialkreislauf treiben die Materialforschung voran, um konventionelle Werkstoffe mit weniger kritischen Zusätzen zu legieren oder sogar vollständig mit nachhaltigeren Alternativen zu substituieren. Eine potenzielle Alternative stellen die intermetallischen Eisenaluminid-Legierungen (FeAl) dar. Im Labormaßstab wurden bereits viele Legierungskonzepte für verbesserte Hochtempera- tureigenschaften oder Duktilität erfolgreich gießtechnisch umgesetzt. Eine erfolgreiche Erprobung von FeAl-Legierungen im industriellen Maßstab stand zu Beginn des Projekts aber weiterhin aus. Ziel des Vorhabens war daher die Entwicklung von simulationsgestützten Gießkonzepten in industrienahe Gießprozesse anhand der Modelllegierung Fe-26Al-4Mo-0,5Ti-1B und die Eingrenzung der prozesstechnischen Verfahrensgrenzen durch Warmrissversuche. Erkenntnisse hieraus wurden in einen praxisorientierten, für zukünftige Anwender in KMUs zugänglichen Handlungskatalog für die gießgerechte Auslegung von Bauteilen aus Eisenaluminiden überführt. Fokus wurde insbesondere auf das Feinguss- und Kokillengussverfahren im Schleuderguss gesetzt. Neben zahlreicher Konstruktions- und Gießprozessparameter wurden auch Wärmebehandlungen und Legierungszusätze (Al, Mo, B) variiert, um den Einfluss von Legierungselementen auf Gießbarkeit, Mikrostruktur und mechanische Kennwerte zu be- stimmen. Eine umfangreiche Basis an Daten aus Mikrostrukturanalysen (Mikroskopische Bildgebung, Bestimmung von Korngrößen sowie Phasenzusammensetzungen und -anteilen, Fraktographie), mechanischen Tests (Härtemessungen, Druckversuch, Zugversuch, Warmzugversuch, Kriechversuch) sowie Messungen thermophysikalischer Eigenschaften konnte für die Modelllegierung erzeugt werden. Korrelationen dieser Informationen mit Prozessvariablen erlaubten Schlussfolgerungen zu Härtungsmechanismen und Duktilität in der Legierung und wie sie prozesstechnisch in Gieß- und Bauteilauslegung gesteuert werden können. Der erfolgreiche Abguss von hochkomplexen Bauteilgeometrien mit dünnen Wandstärken sowie optimierte Legierungszusammensetzungen zeigen Perspektiven auf neue Anwendungsfelder auf.
Das Ziel des Forschungsvorhabens ist erreicht worden.
KW - Simulationsgestützte Gießkonzepte
KW - Intermetallische FeAl-Legierungen
PY - 2023
IS - 1322
SP - 1
EP - 168
PB - Forschungsvereinigung Verbrennungskraftmaschinen (FVV)
CY - Frankfurt am Main
AN - OPUS4-56932
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abel, Andreas
A1 - Zapala, P.
A1 - Michels, H.
A1 - Skrotzki, Birgit
T1 - Materials applications of iron aluminide (FeAl), (WAFEAL)
T1 - Werkstoffanwendungen für Eisenaluminide (FeAl), (WAFEAL)
N2 - The increasing importance of resource availability and closed-loop material cycles are driving materials research to reduce alloying content in conventional materials or even substitute them with more sustainable alternatives. Intermetallic iron aluminide alloys (FeAl) present a potential alternative. Many alloy concepts for improved high-temperature properties or ductility have already been successfully implemented in casting technologies on a laboratory scale. However, successful testing of FeAl alloys on an industrial scale was still pending at the beginning of the project.
Therefore, the aim of the project was to develop simulation based casting concepts for industrial casting processes using the base alloy Fe-26Al-4Mo-0.5Ti-1B and to narrow down process limits by means of hot cracking tests. Findings were transferred into practice-oriented guidelines for casting of iron aluminides, which is accessible to future applicants in SMEs. The focus was placed on centrifugal casting combined with investment casting or die casting. In addition to numerous design and casting process parameters, heat treatments and alloying additions (Al, Mo, B) were varied to determine the influence of alloying elements on castability, microstructure and mechanical properties. Data from microstructure analyses (microscopic imaging, determination of grain sizes as well as phase compositions and volume fractions, fractography), mechanical tests (hardness measurements, compression tests, ambient and high-temperature tensile tests, creep tests) as well as measurements of thermophysical properties could be generated on the base alloy. Correlations of materials data with process variables allowed conclusions to be drawn on strengthening mechanisms and ductility of the alloy and how they can be controlled in terms of processing and component design. Successful casting of highly complex components with thin wall thicknesses and optimised alloy compositions points out prospects for new fields of application.
N2 - Die zunehmende geopolitische Bedeutung der Ressourcenverfügbarkeit sowie die Anforderungen an einen geschlossenen Materialkreislauf treiben die Materialforschung voran, um konventionelle Werkstoffe mit weniger kritischen Zusätzen zu legieren oder sogar vollständig mit nachhaltigeren Alternativen zu substituieren. Eine potenzielle Alternative stellen die intermetallischen Eisenaluminid-Legierungen (FeAl) dar. Im Labormaßstab wurden bereits viele Legierungskonzepte für verbesserte Hochtemperatureigenschaften oder Duktilität erfolgreich gießtechnisch umgesetzt. Eine erfolgreiche Erprobung von FeAl-Legierungen im industriellen Maßstab stand zu Beginn des Projekts aber weiterhin aus.
Ziel des Vorhabens war daher die Entwicklung von simulationsgestützten Gießkonzepten in industrienahe Gießprozesse anhand der Modelllegierung Fe-26Al-4Mo-0,5Ti-1B und die Eingrenzung der prozesstechnischen Verfahrensgrenzen durch Warmrissversuche. Erkenntnisse hieraus wurden in einen praxisorientierten, für zukünftige Anwender in KMUs zugänglichen Handlungskatalog für die gießgerechte Auslegung von Bauteilen aus Eisenaluminiden überführt. Fokus wurde insbesondere auf das Feinguss- und Kokillengussverfahren im Schleuderguss gesetzt. Neben zahlreicher Konstruktions- und Gießprozessparameter wurden auch Wärmebehandlungen und Legierungszusätze (Al, Mo, B) variiert, um den Einfluss von Legierungselementen auf Gießbarkeit, Mikrostruktur und mechanische Kennwerte zu bestimmen. Eine umfangreiche Basis an Daten aus Mikrostrukturanalysen (Mikroskopische Bildgebung, Bestimmung von Korngrößen sowie Phasenzusammensetzungen und -anteilen, Fraktographie), mechanischen Tests (Härtemessungen, Druckversuch, Zugversuch, Warmzugversuch, Kriechversuch) sowie Messungen thermophysikalischer Eigenschaften konnte für die Modelllegierung erzeugt werden. Korrelationen dieser Informationen mit Prozessvariablen erlaubten Schlussfolgerungen zu Härtungsmechanismen und Duktilität in der Legierung und wie sie prozesstechnisch in Gieß- und Bauteilauslegung gesteuert werden können. Der erfolgreiche Abguss von hochkomplexen Bauteilgeometrien mit dünnen Wandstärken sowie optimierte Legierungszusammensetzungen zeigen Perspektiven auf neue Anwendungsfelder auf.
T2 - FVV Transfer + Netzwerktreffen | Informationstagung – Frühjahr 2023
CY - Würzburg, Germany
DA - 29.03.2023
KW - Fe-Al alloys
KW - Intermetallics
KW - Iron aluminides
KW - Microstructure-property-correlation
KW - High temperature mechanical properties
KW - Creep data
KW - Tensile data
KW - Fractography
KW - Casting
PY - 2023
VL - R604
SP - 1
EP - 32
PB - FVV e. V.
CY - Frankfurt a.M.
AN - OPUS4-57247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Towards interoperability: Digital representation of a material specific characterization method
N2 - Certain metallic materials gain better mechanical properties through controlled heat treatments. In age-hardenable aluminum alloys, the strengthening mechanism is based on the controlled formation of nanometer sized precipitates, which hinder dislocation movement. Analysis of the microstructure and especially the precipitates by transmission electron microscopy allows identification of precipitate types and orientations. Dark-field imaging is often used to image the precipitates and quantify their relevant dimensions.
The present work aims at the digital representation of this material-specific characterization method. Instead of a time-consuming, manual image analysis, a digital approach is demonstrated. The integration of an exemplary digital workflow for quantitative precipitation analysis into a data pipeline concept is presented. Here ontologies enable linking of contextual information to the resulting output data in a triplestore. Publishing digital workflow and ontologies ensures the reproducibility of the data. The semantic structure enables data sharing and reuse for other applications and purposes, demonstrating interoperability.
T2 - TMS - 7th World Congress on Integrated Computational Materials Engineering (ICME)
CY - Orlando, Florida, USA
DA - 21.05.2023
KW - Ontology
KW - Semantic Interoperability
KW - Digtial Representation
KW - Data Management
KW - Reproducibility
KW - FAIR
PY - 2023
AN - OPUS4-57548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shakeel, Y.
T1 - NFDI-MatWerk - Reference Datasets
N2 - Within NFDI-MatWerk (“National Research Data Infrastructure for Material Sciences”/ “Nationale Forschungsdateninfrastruktur für Materialwissenschaften und Werkstofftechnik“), the Task Area Materials Data Infrastructure (TA-MDI) will provide tools and services to easily store, share, search, and analyze data and metadata. Such a digital materials environment will ensure data integrity, provenance, and authorship. The MatWerk consortium aims to develop specific solutions jointly with Participant Projects (PPs), which are scientific groups or institutes covering different domains, from theory and simulations to experiments. The Data Exploitation Methods group of the Karlsruhe Institute of Technology-Steinbuch Centre of Computing, as part of TA-MDI, is developing specific solutions in close collaboration with three PPs.
PP07, together with the University of Stuttgart, aims at the image-based prediction of the material properties of stochastic microstructures using large-scale supercomputers. PP13, in cooperation with the University of Saarland, focuses on tomographic methods at various scales in materials research. PP18, together with the Federal Institute for Materials Research and Testing (“Bundesanstalt für Materialforschung und -prüfung”), aspires to define the criteria for materials reference datasets and usage analytics.
The requirements and goals are comparable for each PP: their research outputs, which are scientific datasets, should conform to the FAIR (Findable, Accessible, Interoperable, Reusable) principles. We aim to shape them from a data management perspective making use of the FAIR Digital Object concept, including structured metadata and storage solutions. The results will be a blueprint which will act as a reference for future datasets. Even though the collaboration is in an early stage, the initial steps already show the added value of this approach.
This research has been supported by the Federal Ministry of Education and Research
(BMBF) – funding code M532701 / the Deutsche Forschungsgemeinschaft (DFG, German
Research Foundation) - project number NFDI 38/1, project no. 460247524.
T2 - HMC Conference 2022
CY - Online meeting
DA - 05.10.2022
KW - NFDI
KW - NFDI-MatWerk
KW - Reference Data
KW - FAIR
KW - Creep
PY - 2022
AN - OPUS4-56611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Normung in der Oberflächen-und Schichttechnik
N2 - Report über Normungsaktivitäten im Bereich der Messtechnk an Oberflächen und dünnen Schichten. Übersicht über Methoden und Vorstellung von laufenden Projekten mit Bezug zur Normung
T2 - PlasmaGermany Herbstmeeting 2022
CY - Bielefeld, Germany
DA - 07.11.2022
KW - Oberflächenmesstechnik
KW - Spektroskopie
KW - Ellipsometrie
KW - XPS
KW - Dünne Schichten
PY - 2022
AN - OPUS4-56483
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
T1 - External Liaison Report ISO/TC 202 'Microbeam Analysis' to ISO/TC 229 'Nanotechnologies'
N2 - The liaison report from the ISO Technical Committee ISO/TC 202 'Microbeam Analysis' for the November 2022 ISO/TC 229 Nanotechnologies Plenary Meeting Nanotechnologies Liaison Coordination Group (NLCG) is provided. Essential Information such as newly published standards and projects in develeopment relevant for ISO/TC 229 resulted from the progress within the last year and additional comments on behalf of ISO/TC 202 are included in the report.
KW - ISO/TC 202
KW - ISO/TC 229
KW - VAMAS
KW - Nanotechnologies
KW - Microbeam Analysis
KW - Standardisation
PY - 2022
SP - 1
EP - 4
CY - ISO, Geneva, CH
AN - OPUS4-56734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Nanoparticle Populations
N2 - Two new projects P15 Measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension and P16 Measurement of (relative) number concentration of bimodal silica nanoparticles including deposition from liquid suspension have been started at VAMAS/TWA 34 under the lead of BAM. First results are presented and discussed.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 47th Steering Committee Meeting
CY - Turin, Italy
DA - 18.10.2022
KW - VAMAS
KW - Nanoparticles
KW - Inter-laboratory comparison
KW - Particle size distribution
KW - Nanoparticle concentration
PY - 2022
AN - OPUS4-56196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison of ISO/TC 202 Microbeam Analysis with VAMAS/TWA 37 Quantitative Microstructural Analysis
N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing project "FIB sample processing for TEM" is presented in detail.
T2 - 30th Meeting of ISO/TC 202 Microbeam Analysis
CY - Berlin, Germany
DA - 22.11.2023
KW - VAMAS
KW - ISO/TC 202
KW - Microbeam Analysis
KW - Standardisation
KW - Electron microscopy
KW - FIB
PY - 2023
AN - OPUS4-58984
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pellegrino, F.
T1 - Safe-by-Design Synthesis of 2D Materials
N2 - The use of a dedicated approach: DoE for synthesis + characterization + Chemometric Analysis, is a valuable method for the safe-by-design synthesis of several types of materials for large-scale application in catalysis, energy harvesting, biomedical and environmental applications, etc. This approach is not only related to the material synthesis, but can be expanded to any type of molecules/material, with relevant saving of solvents, energy and times.
T2 - Congress of the Environment and Cultural Heritage - Section of Italian Chemistry Society
CY - Ischia, Italy
DA - 28.09.2023
KW - Safe-by-design
KW - 2D materials
KW - Synthesis
KW - Chemometric analysis
PY - 2023
UR - https://www.congressodabc.it/
AN - OPUS4-59780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - FAIR data in PMD: Development of MSE mid-level and standard-compliant application ontologies
N2 - The efforts taken within the project ‘platform MaterialDigital’ (PMD, materialdigital.de) to store FAIR data in accordance with a standard-compliant ontological representation (‘application ontology’) of a tensile test of metals at room temperature (ISO 6892-1:2019-11) will be presented. This includes the path from developing an ontology in accordance with the respective standard, converting ordinary data obtained from standard tests into the interoperable RDF format, up to connecting the ontology and data. The semantic connection of the ontology and data leads to interoperability and an enhanced ability of querying. For further reusability of data and knowledge semantically stored, the PMD core ontology (PMDco) was developed, which is a mid-level ontology in the field of MSE. The semantic connection of the tensile test application ontology to the PMDco is also presented. Moreover, Ontopanel, a tool for domain experts facilitating visual ontology development and mapping for FAIR data sharing in MSE, is introduced briefly.
T2 - World Congress on Integrated Computational Materials and Engineering (ICME)
CY - Orlando, Florida, USA
DA - 21.05.2023
KW - Digitalization
KW - Semantic Web Technologies
KW - FAIR
KW - Data Interoperability
KW - PMD Core Ontology
KW - Tensile Test Ontology
PY - 2023
AN - OPUS4-57549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Terborg, R.
A1 - Procop, Mathias
T1 - Theoretical calculation and experimental determination of x-ray production efficiencies for copper, zirconium, and tungsten
N2 - The X-ray intensities of the K-, L- and M-lines of copper, zirconium and tungsten have been measured with an energy-dispersive X-ray spectrometer of known efficiency as function of photon energy. X-ray production efficiencies were determined from the measured intensities for Kα- and L-series of Cu and Zr and for the L- and M-series of W. These data were compared to calculated X-ray production efficiencies based on the widely used matrix correction models of Pouchou and Pichoir (XPP) and Bastin (PROZA96).
Our results indicate that a replacement of the stopping power in the PROZA96 algorithm by expressions of Joy and Jablonski has only a minor influence on the calculated X-ray production efficiencies. In contrast, the modifications of the ionization cross-section show a stronger effect. We replaced the ionization cross-sections for K lines of the PROZA96 algorithm with different models.
The results for L- and M-Lines are different. For the L-lines of Cu the original XPP and PROZA96 models show the best agreement while using the Bote cross-sections result in an overestimation. For the Zr-L and W-L1, -L2, -L3 X-ray production efficiencies, the Bote cross-sections lead to a significant improvement compared to all other models. The original XPP model represents the best agreement for the M5 efficiencies but underestimates the M4 efficiencies.
There is no superior model or modification because the parameter sets in the models need to be aligned to each other. However, using the ionization cross-sections of Bote, which are based on quantum mechanical calculations, show promising results in many cases.
KW - X-ray production efficiency
KW - EPMA
KW - Copper
KW - Zirconium
KW - Tungsten
PY - 2023
DO - https://doi.org/10.1093/micmic/ozad067.110
SN - 1435-8115
VL - 29
IS - Supplement 1
SP - 245
EP - 246
PB - Oxford University Press
CY - Oxford
AN - OPUS4-58339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
T1 - Delivering Impact - A new ISO standard on the identification of nanoparticles
N2 - Nanoparticles (NPs) are tiny – around 1 to 100 billionths of a meter – and can have different chemistries and behaviours than the same material of larger size. This property has led to advances in a wide range of industries, but it can also confer toxicity. Size measurements are the main way NPs are identified but a lack of standardised methods for identifying ones with complex shapes has hindered evaluation of their potential harm.
KW - Nanoparticles
KW - Standardisation
KW - Particle size distribution
KW - nPSize
KW - ISO 21363
PY - 2024
UR - https://www.euramet.org/casestudies/casestudiesdetails/news/default-c3b26209e8
SP - 1
EP - 2
PB - EURAMET
CY - Braunschweig
AN - OPUS4-59626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Corrao, Elena
A1 - Gouasmi, Meriem
A1 - Sordello, Fabrizio
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Joerg
A1 - Maurino, Valter
A1 - Pellegrino, Francesco
T1 - Tailoring TiO2 Morphology and Surface Chemistry for Optimized Photocatalytic Activity in rGO Hybrids
N2 - TiO2–reduced graphene oxide (rGO) hybrids were investigated in this study to elucidate how TiO2 morphology and surface chemistry govern charge-transfer pathways and, ultimately, reaction selectivity. Three anatase TiO2 nanostructures were compared: bipyramids predominantly exposing {101} facets (bipy) and two nanosheet-like samples enriched in {001} facets, either fluorinated (n-sh) or thermally defluorinated and {101}-enriched (n-sh_873K). A constant rGO loading (2 wt.%) was introduced via in situ hydrazine reduction of graphene oxide in the presence of TiO2. Photocatalytic activity was evaluated under Xe-lamp irradiation in two model reactions probing oxidative and reductive pathways: phenol degradation and H2 evolution using formic acid as a scavenger. rGO systematically enhanced phenol degradation for all morphologies, with bipy+rGO showing the highest activity. In contrast, H2 evolution was consistently suppressed upon rGO incorporation across all TiO2 samples, although the bipyramidal morphology remained the most active within each series. These results highlight that facet exposure and surface functionalization dictate the beneficial or detrimental role of rGO depending on the targeted photocatalytic pathway.
KW - Photocatalytic activity
KW - Reduced graphene oxide
KW - TiO2
KW - Surface chemistry
KW - 2D materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653476
DO - https://doi.org/10.26434/chemrxiv-2026-65917
SP - 1
EP - 12
PB - American Chemical Society (ACS)
AN - OPUS4-65347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dak, Gaurav
A1 - Barik, Birendra Kumar
A1 - Chaurasia, Prashant Kumar
A1 - Gottschalk, Götz-Friedrich
A1 - Shahane, Akshay Manoj
A1 - Goecke, Sven-F.
A1 - De, Amitava
T1 - Probing dimensional consistency of deposited structures during out-of-position wire arc directed energy deposition
N2 - Wire arc directed energy deposition (DED-Arc) using a gas metal arc (GMA) welding power source is cited as DED-GMA that fabricates a part by layer-by-layer deposition of molten wire droplets along horizontal and out-of-position inclined trajectories. For the out-of-position trajectories, a smooth deposition of material is impaired by the gravitational force on the molten wire droplets, resulting in uneven and inconsistent deposit profiles. We present here a detailed experimental investigation to realize the effect of the out-of-position inclinations on the quality of the deposited structure for DED-GMA with a steel and an aluminium filler wire. The evolution of the droplet transfer and melt pool during the out-of-position inclined deposition is probed through high-speed videography at different baseplate angles and commonly used scanning strategies. An analytical model is proposed further based on force equilibrium analysis for a prior estimation of the out-of-position inclined deposit profile, which can help design dimensionally consistent and structurally sound parts using DED-GMA.
KW - DED-Arc
KW - Additive manufacturing
KW - Out-of-position deposition
KW - High-speed videography
KW - Force
PY - 2025
DO - https://doi.org/10.1007/s40194-025-02291-0
SN - 0043-2288
SP - 1
EP - 20
PB - Springer Science and Business Media LLC
AN - OPUS4-65350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Narayanan, M.M.
A1 - Nicolai, M.
A1 - Prager, J.
T1 - C9-a5 - Optimization of Low-Frequency Shear Wave Transducers for Guided Wave Applications
N2 - Development of ultrasonic transducers for the excitation of a torsional mode T(0,1) mode in a large pipe of the material typical of actual oil/gas pipelines is discussed. Towards this,16 ultrasonic transducers are designed and fabricated using shear plates of PIC 255 material, backing mass of tungsten-epoxy composite and brass shims as wear plates. The transducers are qualified using Laser Doppler Vibrometry. Then, the transducers are embedded in a springloaded ring and tested on a pipe using a multi-channel ultrasonic system. The results show the successful excitation of T(0,1) mode and it is seen to propagate for distance of 60 m with a good SNR.
T2 - 2025 ICU PADERBORN - 9th International Congress on Ultrasonics
CY - Paderborn, Germany
DA - 21.09.2025
KW - Ultrasonic guided waves
KW - Torsional mode
KW - Shear PZT plates
KW - Ring array transducer design
KW - Pipe testing
PY - 2025
DO - https://doi.org/10.5162/Ultrasonic2025/C9-a5
SP - 223
EP - 226
PB - AMA Service GmbH
AN - OPUS4-65356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zeipert, H.
A1 - Nellius, T.
A1 - Schönlau, N.
A1 - Wippermann, M.
A1 - Claes, L.
A1 - Henning, B.
A1 - Nicolai, Marcel
A1 - Prager, J.
T1 - C6-a3 - Monitoring the curing process of adhesive bonds using selective excitation of guided ultrasonic waves
N2 - A measurement setup for the selective excitation of guided ultrasonic waves in adhesively bonded plates is introduced. Changes of the dispersive behaviour of the guided waves during the curing process is known to be accompanied by a change in the propagating waves group velocities. The proposed measurement setup is used to monitor that change during the curing process of an aluminium-epoxy-polycarbonate bond.
T2 - 2025 ICU PADERBORN - 9th International Congress on Ultrasonics
CY - Paderborn, Germany
DA - 21.09.2025
KW - Ultrasonic guided waves
KW - Selective excitation
KW - Non-destructive testing
KW - Adhesive bonding
KW - Condition monitoring
PY - 2025
DO - https://doi.org/10.5162/Ultrasonic2025/C6-a3
SP - 207
EP - 210
PB - AMA Service GmbH
AN - OPUS4-65357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stargardt, Patrick
A1 - Bresch, Sophie
A1 - Falkenberg, Rainer
A1 - Mieller, Björn
T1 - Effect of Reaction Layers on Internal Stresses in Co‐Fired Multilayers of Calcium Manganate and Calcium Cobaltite
N2 - A widespread recovery of waste heat requires a cost‐effective production of thermoelectric generators. Thermoelectric oxides are predestined for use at high temperatures. For manufacturing reasons, a multilayer generator design will be easily scalable and cost‐effective. To evaluate the potential of ceramic multilayer technology for that purpose, a multilayer of the promising thermoelectric oxides calcium cobaltite (Ca3Co4O9), calcium manganate (CMO, CaMnO3), and glass–ceramic insulation layers is fabricated. Cracks and reaction layers at the interfaces are observed in the microstructure. The compositions of these reaction layers are identified by energy‐dispersive X‐ray spectroscopy and X‐ray diffraction. Mechanical and thermal properties of all layers are compiled from literature or determined by purposeful sample preparation and testing. Based on this data set, the internal stresses in the multilayer after co‐firing are calculated numerically. It is shown that tensile stresses in the range of 50 MPa occur in the CMO layers. The reaction layers have only a minor influence on the level of these residual stresses. Herein, it is proven that the material system is basically suitable for multilayer generator production, but that the co‐firing process and the layer structure must be adapted to improve densification and reduce the tensile stresses in the CMO.
KW - Ceramic multilayers
KW - Co-firings
KW - Internal stresses
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601626
DO - https://doi.org/10.1002/pssa.202300956
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-60162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eddah, Mustapha
A1 - Markötter, Henning
A1 - Mieller, Björn
A1 - Widjaja, Martinus Putra
A1 - Beckmann, Jörg
A1 - Bruno, Giovanni
T1 - Multi-energy high dynamic range synchrotron X-ray computed tomography
N2 - Synchrotron X-ray computed tomography (SXCT) is regularly used in materials science to correlate structural properties with macroscopic properties and to optimize manufacturing processes. The X-ray beam energy must be adapted to the sample properties, such as size and density. If both strongly and weakly absorbing materials are present, the contrast to the weakly absorbing materials is lost, resulting in image artifacts and a poor signal-tonoise ratio (SNR). One particular example is a low-temperature co-fired ceramics (LTCC), in which metal connections are embedded in a ceramic matrix and form 3-dimensional conducting structures. This article describes a method of combining SXCT scans acquired at different beam energies, significantly reducing metal artifacts, and improving image quality. We show how to solve the difficult task of merging the scans at low and high beam energy. Our proposed merging approach achieves up to 35 % improvement in SNR within ceramic regions adjacent to metallic conductors. In this way, previously inaccessible regions within the ceramic structure close to the metallic conductors are made accessible. The paper further discusses methodological requirements, limitations, and potential extensions of the presented multi-energy SXCT merging technique.
KW - Synchrotron computed tomography
KW - Reconstruction algorithm
KW - High dynamic range
KW - Data merging
KW - Low-temperature cofired ceramics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652339
DO - https://doi.org/10.1016/j.tmater.2025.100079
SN - 2949-673X
VL - 9
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Günster, Jens
T1 - Towards a debinding-free additive manufacturing of ceramics: A development perspective of water-based LSD and LIS technologies
N2 - Ceramic additive manufacturing (AM) requires a complex process chain with various post-processing steps that require expensive machines and special expertise. The key to further market penetration is AM that makes it possible to integrate into an already established ceramic process chain. Most successful AM technologies for ceramics are, however, based on processes that initially have been developed for polymeric materials. For ceramics AM, polymers or precursors are loaded with ceramic particles. This strategy facilitates the entry into AM, however the introduction of organic additives into the ceramic process chain represents a considerable technological challenge to ultimately obtain a ceramic component after additive shaping. In the present communication, two technologies based on ceramic suspensions will be introduced, the “layerwise slurry deposition” (LSD) and “laser induced slip casting” (LIS) technology. Both technologies take advantage of the high packing densities reached by conventional slip casting and moreover enable the processing of fines, even nanoparticles.
KW - Additive Manufacturing
KW - Ceramic
KW - Water-based
KW - Debinding
KW - Slurry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605531
DO - https://doi.org/10.1016/j.oceram.2024.100632
SN - 2666-5395
VL - 19
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, Charlotte
A1 - Katz, Aaron
A1 - Feldmann, Ines
A1 - Laux, Peter
A1 - Luch, Andreas
A1 - Tschiche, Harald R.
T1 - A targeted fluorescent nanosensor for ratiometric pH sensing at the cell surface
N2 - AbstractThe correlation between altered extracellular pH and various pathological conditions, including cancer, inflammation and metabolic disorders, is well known. Bulk pH measurements cannot report the extracellular pH value at the cell surface. However, there is a limited number of suitable tools for measuring the extracellular pH of cells with high spatial resolution, and none of them are commonly used in laboratories around the world. In this study, a versatile ratiometric nanosensor for the measurement of extracellular pH was developed. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with the pH-inert reference dye Nile red and is surface functionalized with a pH-responsive fluorescein dye. Equipped with a targeting moiety, the nanosensor can adhere to cell membranes, allowing direct measurement of extracellular pH at the cell surface. The nanosensor exhibits a sensitive ratiometric pH response within the range of 5.5–9.0, with a calculated pKa of 7.47. This range optimally covers the extracellular pH (pHe) of most healthy cells and cells in which the pHe is abnormal, such as cancer cells. In combination with the nanosensors ability to target cell membranes, its high robustness, reversibility and its biocompatibility, the pHe nanosensor proves to be well suited for in-situ measurement of extracellular pH, even over extended time periods. This pH nanosensor has the potential to advance biomedical research by improving our understanding of cellular microenvironments, where extracellular pH plays an important role.
KW - pH sensor
KW - pH
KW - Targeting, Nanoparticles
KW - pHe
KW - Nanosensor
KW - Extracellular pH
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604339
DO - https://doi.org/10.1038/s41598-024-62976-2
VL - 14
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-60433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Moritz
A1 - Stawarczyk, Bogna
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Influence of additives and binder on the physical properties of dental silicate glass-ceramic feedstock for additive manufacturing
N2 - Objectives
The aim of the study was to investigate the impact of organic additives (binder, plasticizer, and the cross-linking ink) in the formulation of water-based feedstocks on the properties of a dental feldspathic glass-ceramic material developed for the slurry-based additive manufacturing technology “LSD-print.”
Material and methods
Three water-based feldspathic feedstocks were produced to study the effects of polyvinyl alcohol (AC1) and poly (sodium 4-styrenesulfonate) (AC2) as binder systems. A feedstock without organic additives was tested as the control group (CG). Disc-shaped (n = 15) and bar (n = 7) specimens were slip-cast and characterized in the green and fired states. In the green state, density and flexural strength were measured. In the fired state, density, shrinkage, flexural strength (FS), Weibull modulus, fracture toughness (KIC), Martens parameters, and microstructure were analyzed. Disc-shaped and bar specimens were also cut from commercially available CAD/CAM blocks and used as a target reference (TR) for the fired state.
Results
In the green state, CG showed the highest bulk density but the lowest FS, while the highest FS in the green state was achieved with the addition of a cross-linking ink. After firing, no significant differences in density and a similar microstructure were observed for all slip-cast groups, indicating that almost complete densification could be achieved. The CAD/CAM specimens showed the highest mean FS, Weibull modulus, and KIC, with significant differences between some of the slip-cast groups.
Significance
These results suggest that the investigated feedstocks are promising candidates for the slurry-based additive manufacturing of restorations meeting the class 1a requirements according to DIN EN ISO 6871:2019–01.
KW - Firing
KW - 3D-printing
KW - Silicate glass-ceramics
KW - Debinding
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600516
DO - https://doi.org/10.1016/j.jmbbm.2024.106563
SN - 1751-6161
VL - 155
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-60051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knabe, C.
A1 - Stiller, M.
A1 - Kampschulte, M.
A1 - Wilbig, Janka
A1 - Peleska, B.
A1 - Günster, Jens
A1 - Gildenhaar, R.
A1 - Berger, G.
A1 - Rack, A.
A1 - Linow, U.
A1 - Heiland, M.
A1 - Rendenbach, C.
A1 - Koerdt, S.
A1 - Steffen, C.
A1 - Houshmand, A.
A1 - Xiang-Tischhauser, L.
A1 - Adel-Khattab, D.
T1 - A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects in vivo
N2 - Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur.
KW - Additive Manufacturing
KW - Bio active ceramic
KW - In-vivo
KW - Alcium alkali phosphate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584555
DO - https://doi.org/10.3389/fbioe.2023.1221314
SN - 2296-4185
VL - 11
SP - 1
EP - 20
PB - Frontiers SA
CY - Lausanne
AN - OPUS4-58455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knabe, Christine
A1 - Adel-Khattab, Doaa
A1 - Rezk, Mohamed
A1 - Cheng, Jia
A1 - Berger, Georg
A1 - Gildenhaar, Renate
A1 - Wilbig, Janka
A1 - Günster, Jens
A1 - Rack, Alexander
A1 - Heiland, Max
A1 - Knauf, Tom
A1 - Stiller, Michael
T1 - Osteogenic Effect of a Bioactive Calcium Alkali Phosphate Bone Substitute in Humans
N2 - (1) Background: The desire to avoid autograft harvesting in implant dentistry has prompted an ever-increasing quest for bioceramic bone substitutes, which stimulate osteogenesis while resorbing in a timely fashion. Consequently, a highly bioactive silicon containing calcium alkali orthophosphate (Si-CAP) material was created, which previously was shown to induce greater bone cell maturation and bone neo-formation than β-tricalcium phosphate (β-TCP) in vivo as well as in vitro. Our study tested the hypothesis that the enhanced effect on bone cell function in vitro and in sheep in vivo would lead to more copious bone neoformation in patients following sinus floor augmentation (SFA) employing Si-CAP when compared to β-TCP. (2) Methods: The effects of Si-CAP on osteogenesis and Si-CAP resorbability were evaluated in biopsies harvested from 38 patients six months after SFA in comparison to β-TCP employing undecalcified histology, histomorphometry, and immunohistochemical analysis of osteogenic marker expression. (3) Results: Si-CAP as well as β-TCP supported matrix mineralization and bone formation. Apically furthest away from the original bone tissue, Si-CAP induced significantly higher bone formation, bone-bonding (bone-bioceramic contact), and granule resorption than β-TCP. This was in conjunction with a higher expression of osteogenic markers. (4) Conclusions: Si-CAP induced higher and more advanced bone formation and resorbability than β-TCP, while β-TCP’s remarkable osteoconductivity has been widely demonstrated. Hence, Si-CAP constitutes a well-suited bioactive graft choice for SFA in the clinical arena.
KW - Silicon release
KW - Bioceramics
KW - Calcium alkali orthophosphate materials
KW - Bioactive bone grafting material
KW - Bioactivity
KW - Osteogenesis
KW - Bone regeneration
KW - Sinus floor augmentation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591015
DO - https://doi.org/10.3390/bioengineering10121408
VL - 10
IS - 12
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-59101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, Juan Carlos
A1 - Fateri, Miranda
A1 - Kalhöfer, Eckhard
A1 - Schubert, Tim
A1 - Meyer, Lena
A1 - Kolsch, Nico
A1 - Brandic Lipinska, Monica
A1 - Davenport, Robert
A1 - Imhof, Barbara
A1 - Waclavicek, René
A1 - Sperl, Matthias
A1 - Makaya, Advenit
A1 - Günster, Jens
T1 - Laser melting manufacturing of large elements of lunar regolith simulant for paving on the Moon
N2 - The next steps for the expansion of the human presence in the solar system will be taken on the Moon. However, due to the low lunar gravity, the suspended dust generated when lunar rovers move across the lunar soil is a significant risk for lunar missions as it can affect the systems of the exploration vehicles. One solution to mitigate this problem is the construction of roads and landing pads on the Moon. In addition, to increase the sustainability of future lunar missions, in-situ resource utilization (ISRU) techniques must be developed. In this paper, the use of concentrated light for paving on the Moon by melting the lunar regolith is investigated. As a substitute of the concentrated sunlight, a high-power CO2 laser is used in the experiments. With this set-up, a maximum laser spot diameter of 100 mm can be achieved, which translates in high thicknesses of the consolidated layers. Furthermore, the lunar regolith simulant EAC-1A is used as a substitute of the actual lunar soil. At the end of the study, large samples (approximately 250 × 250 mm) with interlocking capabilities were fabricated by melting the lunar simulant with the laser directly on the powder bed. Large areas of lunar soil can be covered with these samples and serve as roads and landing pads, decreasing the propagation of lunar dust. These manufactured samples were analysed regarding their ineralogical composition, internal structure and mechanical properties.
KW - Regolith
KW - ISRU
KW - Moon
KW - Laser
KW - Additive manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585985
DO - https://doi.org/10.1038/s41598-023-42008-1
SN - 2045-2322
VL - 13
SP - 1
EP - 10
PB - Springer
AN - OPUS4-58598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - Hans, Ann-Kathrin
A1 - von der Au, Marcus
A1 - Brand, Izabella
A1 - Wittstock, Gunther
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - Long-term corrosion studies of CrCoNi and CrMnFeCoNi in sulfuric acid
N2 - This study investigates the long-term corrosion behavior of CrCoNi and CrMnFeCoNi MPEAs over 28 d in 1 M H2SO4. Corrosion progression and passive film evolution were analyzed using open circuit potential measurements, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Unlike short-term polarization tests, where CrCoNi exhibited intergranular corrosion, long-term immersion resulted in a stable, Cr-rich passive oxide layer. In contrast, CrMnFeCoNi formed a porous mixed oxide layer, increasing its susceptibility to degradation and revealing a distinct corrosion mechanism. X-ray photoelectron spectroscopy tracking at weekly intervals showed that prolonged immersion led to the transformation of sulfide/sulfite species into a sulfate-containing surface film. This effect was only detectable in long-term corrosion studies. These findings provide new insights into the time-dependent degradation mechanisms of MPEAs and demonstrate that corrosion mechanisms differ significantly from short-term polarization tests. This highlights the need for long-term studies to properly assess material stability in practical applications.
KW - Long-term corrosion
KW - Multi-principal element alloys (MPEAs)
KW - X-ray photoelectron spectroscopy (XPS)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636895
DO - https://doi.org/10.1038/s41529-025-00637-z
SN - 2397-2106
VL - 9
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-63689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sobetkii, Arcadii
A1 - Mosinoiu, Laurentiu-Florin
A1 - Caramarin, Stefania
A1 - Mitrica, Dumitru
A1 - Cursaru, Laura-Madalina
A1 - Matei, Alexandru-Cristian
A1 - Tudor, Ioan-Albert
A1 - Serban, Beatrice-Adriana
A1 - Ghita, Mihai
A1 - Vitan, Nicoleta
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
A1 - Postolnyi, Bogdan
A1 - Pogrebnjak, Alexander
T1 - Deposition and Characterization of Cu-Enhanced High-Entropy Alloy Coatings via DC Magnetron Sputtering
N2 - Protection against microbiologically influenced corrosion (MIC) is critical for materials used in aquatic environments, as MIC accelerates material degradation and leads to faster structural failure. Copper (Cu) has the potential to substantially improve the MIC resistance in alloys. In this study, high-entropy alloy (HEA) coatings containing Cu were deposited using DC (Direct Current) magnetron sputtering to enhance the corrosion resistance and mechanical properties of various substrates. Two CuCrFeMnNi HEA compositions in the form of bulk alloys and PVD (Physical Vapor Deposition) coatings, with 5% and 10% Cu, were analyzed for their microstructural, mechanical, and anticorrosive characteristics. Deposition parameters were varied to select the optimal values. Microstructural evaluations using SEM-EDS (scanning electron microscopy and energy dispersive X-ray spectroscopy), XRD (X-ray diffraction), and AFM (atomic force microscopy) revealed uniform, dense coatings with good adhesion composed of dendritic and interdendritic BCC (body-centered cubic) and FCC (face centered cubic) structures, respectively. Microhardness tests indicated improved mechanical properties for the samples coated with developed HEAs. The coatings exhibited improved corrosion resistance in NaCl solution, the 10% Cu composition displaying the highest polarization resistance and lowest corrosion rate. These findings suggest that Cu-containing HEA coatings are promising candidates for applications requiring enhanced corrosion protection.
KW - High-entropy alloys (HEAs)
KW - DC magnetron sputtering
KW - Cu-enhanced coatings
KW - Corrosion resistance
KW - Microstructural characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625561
DO - https://doi.org/10.3390/app15041917
SN - 2076-3417
VL - 15
IS - 4
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-62556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna
A1 - König, N.F.
A1 - De Marzi, A.
A1 - Zocca, Andrea
A1 - Franchin, G.
A1 - Bermejo, R.
A1 - Colombo, P.
A1 - Günster, Jens
T1 - Linear volumetric additive manufacturing of zirconia from a transparent photopolymerizable ceramic slurry via Xolography
N2 - Advanced ceramics printed with photon-based additive manufacturing deals with anisotropic mechanical properties from the layer-by-layer manufacturing. Motivated by the success in using highly filled transparent slurries containing nanoparticles for powder-based two-photon-polymerization (2PP) for advanced ceramic printing, this works approach is the transfer to Xolography, a volumetric additive manufacturing technology based on linear two-photon excitation and without recoating steps. This paper reports the results of a preliminary investigation optimizing the photocurable slurry to the requirements of Xolography in terms of transparency, over a significantly larger mean free path, compared to 2PP. A feedstock filled with 70 % weight fraction of ceramic particles (∼30 vol%) exhibiting an exceptionally high degree of transparency in the relevant wavelength range of 400–800 nm was prepared from 5 nm zirconia nanoparticles. The high transparency of the photocurable slurry is attributed to the near-monomodal particle size distribution of the zirconia nanoparticles used.
KW - Additive manufacturing
KW - Xolography
KW - Ceramic
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608908
DO - https://doi.org/10.1016/j.oceram.2024.100655
SN - 2666-5395
VL - 19
SP - 1
EP - 9
PB - Elsevier BV
AN - OPUS4-60890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
T1 - Binder Jetting of Advanced Ceramics
N2 - The Binder Jetting BJ process is one of the most versatile additive manufacturing technologies in use. In this process a binder is locally jetted into a powder bed for the consolidation of a 3D structure, layer by layer. Basically, all materials which can be provided as a flowable powder and, thus, spreadable to a thin layer, can be processed. Metals, ceramics and polymers are processable, but also materials from nature, such as sand, wood sawdust and insect frass. Moreover, the BJ technology is adapted to large building volumes of some cubic meters easily. Besides these striking advantages, the manufacture of ceramic parts by BJ is still challenging, as the packing density of the powder bed is generally too low and the particle size of a flowable powder too large for a successful densification of printed parts in a subsequent sintering step to an advanced ceramic product. After an introduction of binder jetting in general and highlighting some examples, strategies for obtaining dense ceramic parts by BJ will be introduced.
T2 - yCAM 2022
CY - Barcelona, Spain
DA - 08.11.2022
KW - Additive Manufacturing
KW - Ceramics
PY - 2022
AN - OPUS4-59887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rütters, H.
A1 - Fischer, S.
A1 - Le, Quynh
A1 - Bettge, Dirk
A1 - Bäßler, Ralph
A1 - Maßmann, J.
A1 - Ostertag-Henning, C.
A1 - Wolf, J. Lennard
A1 - Pumpa, M.
A1 - Lubenau, U.
A1 - Knauer, S.
A1 - Jaeger, P.
A1 - Neumann, A.
A1 - Svensson, K.
A1 - Lempp, C.
A1 - Menezes, F.
A1 - Hagemann, B.
T1 - Towards defining reasonable minimum composition thresholds – impacts of variable CO2 stream compositions on transport, injection and storage
N2 - The collaborative project “Impacts of impurities in CO2 streams captured from different emitters in a regional cluster on transport, injection and storage (CLUSTER)” aimed to set up recommendations on how to define “reasonable minimum composition thresholds” that CO2 streams should meet when accessing CO2 transport pipeline networks. Within CLUSTER, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the whole CCS chain. Investigations included, amongst others, impacts on: Corrosion of pipeline steel, pipeline network design and related transport costs, alteration of well bore cements, pressure development and rock integrity, geochemical reactions, and petrophysical and geomechanical rock properties.
All investigations are based on a generic CCS chain scenario. In this scenario, CO2 streams are captured from a spatial cluster of eleven emitters and collected in a regional pipeline network. Emitters comprise seven fossil fuel-fired power plants equipped with different capture technologies, two cement plants, one refinery and one integrated iron and steel plant. In total, 19.78 Mio t CO2 (including impurities) are captured in the emitter cluster annually. The combined CO2 stream is transported in a trunk line with a length of 400 km (100 km of these offshore) and is injected into five generic storage structures. The storage reservoirs are saline aquifers of the Buntsandstein.
The investigations revealed beneficial and deteriorating impacts of different impurities and combinations thereof. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the modelled variable compositions and mass flow rates were observed. Based on the results, the CLUSTER project team recommends not to define “minimum composition thresholds” for CO2 streams as strict threshold values for each individual impurity in the stream. Instead, CO2 stream compositions and variabilities for specific CCS projects should be constrained with regard to a set of parameters including i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of CO2 stream composition, and iv) impurity combinations to be avoided.
T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15
CY - Online meeting
DA - 15.03.2021
KW - Corrosion
KW - Impurities
KW - CO2 quality
KW - Pipeline network
KW - Whole-chain CCS scenario
KW - Recommendations
PY - 2021
DO - https://doi.org/10.2139/ssrn.3816427
SP - 1
EP - 18
AN - OPUS4-52418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Polymer Coatings ‐ A Guide to Chemistry, Characterization, and Selected Applications
N2 - This book grew out of a course on polymer coatings held by the author at the university. It shall serve as an introduction to the wide field of polymer coatings. It is not intended to cover completely all facts on polymer coatings.
All chapters are well structured. Selected figures and formulas illustrate the content and contribute to a good understandability. At the end of each chapter some hints for further reading are provided.
Finally, the book fulfills its intention to introduce into the topic by providing basics on science and technology of polymer coatings, suitable for chemists in industry, materials scientists, polymer chemists and physical chemists.
KW - Corrosion
KW - Coating
KW - Polymer
PY - 2020
DO - https://doi.org/10.1002/maco.202070024
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 2
SP - 321
EP - 322
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stoljarova, A.
A1 - Regenspurg, S.
A1 - Bäßler, Ralph
A1 - Mathiesen, T.
A1 - Braüner Nielsen, J.
T1 - Effect of lead and copper containing brine on steel materials for geothermal applications – A corrosion study
N2 - Geothermal brines often contain high amounts of lead and copper ions that can precipitate as native Cu and Pb as consequence of galvanic corrosion when brines react with carbon steel materials. This contribution evaluates which materials could overcome the problem of galvanic corrosion at geothermal environment.
The behavior of these materials in water containing high chloride concentration (> 100 g/L NaCl) as well as various amounts of dissolved bCl2 and/or CuCl2 was characterized by electrochemical and exposure measurements.
Both methods reveal carbon steel suffers corrosion susceptibility, accompanied by Cu◦ and/or Pb◦ precipitation on the surface. Electrochemical measurements on stainless steels result in significant difference in corrosion and repassivation potentials (Ecorr = -189 mV, Erep = 70 mV), indicating a good corrosion resistance.
KW - Copper
KW - Lead
KW - Corrosion
KW - Steel
KW - Geothermal energy
PY - 2021
DO - https://doi.org/10.1016/j.geothermics.2020.102024
SN - 0375-6505
VL - 91
SP - NIL_75
EP - NIL_85
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diener, S.
A1 - Schubert, Hendrik
A1 - Held, A.
A1 - Katsikis, N.
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Influence of the dispersant on the parts quality in slurry-based binder jetting of SiC ceramics
N2 - Binder jetting is establishing more and more in the ceramic industry to produce large complex shaped parts. A parameter with a great impact on the quality of the parts is the binder–powder interaction. The use of ceramic slurries as feedstock for this process, such as in the layerwise slurry deposition–print technology, allows a great flexibility in the composition. Such slurries are typically composed of ceramic powder, water, and small amounts of various additives. The understanding of the effect of these components on the printing quality is thus essential for the feedstock development. Four models were developed regarding the impact of additives, such as dispersants on printing. These models were confirmed or rebutted by experiments performed for an SiC slurry system with two different concentrations of a dispersant and a commercial phenolic resin used as a binder. It is shown that for this system the influence of the dispersant on the curing behavior and the clogging of the pores by dispersant can be neglected. The redispersion of the dispersant after the curing of the resin has no or only a minor effect. However, the wetting behavior determined by the surface energies of the system seem to be most crucial. In case the surface energy of the slurry additive is significantly lower than the surface energy of the binder, the strength of the green parts and the printing quality will be low. This was shown by inverse gas chromatography, contact angle measurement, rheological characterization, and mechanical tests with casted samples.
KW - Additive Manufacturing
KW - Binder Jetting
KW - Layerwise slurry deposition
KW - Silicon carbide
KW - Wetting
PY - 2022
DO - https://doi.org/10.1111/jace.18693
SN - 1551-2916
VL - 2022
SP - 1
EP - 15
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-55542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - Combination of layerwise slurry deposition and binder jetting (lsd-print) for the additive manufacturing of advanced ceramic materials
N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. Powder bed fusion and binder jetting especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability. The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders. In this context, the “layerwise slurry deposition” (LSD) has been developed as a layer deposition method which enables the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder layer. This offers high flexibility in the ceramic feedstock used, especially concerning material and particle size. The LSD technology can be combined with binder jetting to develop the so-called “LSDprint” process for the additive manufacturing of ceramics. The LSDprint technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to those achieved by traditional processing. In this presentation, the LSD process will be introduced and several examples of application ranging from silicate to high-performance ceramics will be shown. Recent developments towards the scale-up and industrialization of this process will be discussed, alongside future perspectives for the multi-material additive manufacturing.
T2 - Shaping 8
CY - Dübendorf, Switzerland
DA - 14.09.2022
KW - Additive Manufacturing
KW - 3D printing
KW - Ceramics
PY - 2022
AN - OPUS4-56523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
T1 - Ceramic Processing with Light
N2 - In order to be able to manipulate ceramic powder compacts and ceramic suspensions (slurries) in their volume with light, a minimum transparency of the materials is required. Compared to polymers and metals, ceramic materials are characterized by the fact that they have a wide electronic band gap and therefore a wide optical window of transparency. The optical window generally ranges from less than 0.3 µm to 5 µm wavelength. Therefore, to focus light into the volume of a ceramic powder compact, its light scattering properties need to be tailored. In this study, we present the physical background and material development strategies for the application of two-photon polymerization (2PP), Xolography and selective volumetric sintering for the additive manufacturing of structures in the volume of ceramic slips and green compacts.
T2 - CMCEE 14
CY - Budapest, Hungary
DA - 18.08.2024
KW - Ceramic
KW - Additive manufacturing
KW - Light
PY - 2024
AN - OPUS4-60892
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolsch, Nico
T1 - Enabling online quality control of powder deposition for 3d printing in microgravity
N2 - 3D printing or additive manufacturing in space is of great value for long-term human spaceflight missions and space stations, conveniently offering access to a ‘virtual warehouse’ of tools and spare parts on the push of a button. The process only needs one type of feedstock such as powder or filament and only as much material as the final part requires, giving it a huge weight benefit over traditional subtractive methods.
While 3D printers are already operational on the ISS since 2014, the utilized processes are only capable of manufacturing relatively low strength parts from polymers not suitable for many tools or critical components. To gain access to high quality metal prints, a modified Laser Powder Bed Fusion (LPBF) process was developed to stabilize the critical powder bed in microgravity through a gas flow [2]. This setup was able to generate a (miniature) steel wrench during parabolic flights, but a reliable layer deposition has raised challenges due to the combination of gas flow parameters with microgravity conditions. Furthermore, the quality and density of the powder bed, which is critical for the process, cannot be examined afterward on the ground. This is due to hyper gravity phases during the flight that are influencing the properties of the powder bed.
In this paper, the challenges of the layer deposition are revised, and the subsequent evolution of the recoating system explained. Later, the challenges of an in-situ quality control, evaluation, and quantification of the properties of the powder bed are examined. As a solution, a high-resolution line-scanner is proposed and its implementation int the compact LPBF system demonstrated. Its ability to measure common defects such as ridges in the deposited layer is shown in experiments at normal gravity. As an illustration, Figure 1 shows an extreme case of the formation of ridges.
T2 - European Conference on Spacecraft Structures Materials and Environmental Testing
CY - Toulouse, France
DA - 28.03.2023
KW - Additive manufacturing
KW - In-space manufacturing
KW - Online quality control
KW - Microgravity
KW - Powder deposition
PY - 2023
AN - OPUS4-57249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aristia, Gabriela
A1 - Le, Quynh Hoa
A1 - Nofz, Marianne
A1 - Sojref, Regine
A1 - Bäßler, Ralph
T1 - Study of Al2O3 Sol-Gel Coatings on X20Cr13 in Artificial North German Basin Geothermal Water at 150 °C
N2 - Al2O3 has been widely used as a coating in industrial applications due to its excellent chemical and thermal resistance. Considering high temperatures and aggressive mediums exist in geothermal systems, Al2O3 can be a potential coating candidate to protect steels in geothermal applications. In this study, γ-Al2O3 was used as a coating on martensitic steels by applying AlOOH sol followed by a heat treatment at 600 °C. To evaluate the coating application process, one-, two-, and three-layer coatings were tested in the artificial North German Basin (NGB), containing 166 g/L Cl−, at 150 °C and 1 MPa for 168 h. To reveal the stability of the Al2O3 coating in NGB solution, three-layer coatings were used in exposure tests for 24, 168, 672, and 1296 h, followed by surface and cross-section characterization. SEM images show that the Al2O3 coating was stable up to 1296 h of exposure, where the outer layer mostly transformed into boehmite AlOOH with needle-like crystals dominating the surface. Closer analysis of cross-sections showed that the interface between each layer was affected in long-term exposure tests, which caused local delamination after 168 h of exposure. In separate experiments, electrochemical impedance spectroscopy (EIS) was performed at 150 °C to evaluate the changes of coatings within the first 24 h. Results showed that the most significant decrease in the impedance is within 6 h, which can be associated with the electrolyte penetration through the coating, followed by the formation of AlOOH. Here, results of both short-term EIS measurements (up to 24 h) and long-term exposure tests (up to 1296 h) are discussed.
KW - Al2O3
KW - Geothermal
KW - Martensitic steels
KW - Behmite
KW - Corrosion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525551
DO - https://doi.org/10.3390/coatings11050526
SN - 2079-6412
VL - 11
IS - 5
SP - 526
PB - MDPI
CY - Basel
AN - OPUS4-52555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - An, Biwen Annie
A1 - Kleinbub, Sherin
A1 - Özcan Sandikcioglu, Özlem
A1 - Koerdt, Andrea
T1 - Iron to Gas: Versatile Multiport Flow-Column Revealed Extremely High Corrosion Potential by Methanogen-Induced Microbiologically Influenced Corrosion (Mi-MIC)
N2 - Currently, sulfate-reducing bacteria (SRB) is regarded as the main culprit of microbiologically influenced corrosion (MIC), mainly due to the low reported corrosion rates of other microorganisms. For example, the highest reported corrosion rate for methanogens is 0.065 mm/yr. However, by investigating methanogen-induced microbiologically influenced corrosion (Mi-MIC) using an in-house developed versatile multiport flow test column, extremely high corrosion rates were observed. We analyzed a large set of carbon steel beads, which were sectionally embedded into the test columns as substrates for iron-utilizing methanogen Methanobacterium IM1. After 14 days of operation using glass beads as fillers for section separation, the highest average corrosion rate of Methanobacterium IM1 was 0.2 mm/yr, which doubled that of Desulfovibrio ferrophilus IS5 and Desulfovibrio alaskensis 16109 investigated at the same conditions. At the most corroded region, nearly 80% of the beads lost 1% of their initial weight (fast-corrosion), resulting in an average corrosion rate of 0.2 mm/yr for Methanobacterium IM1-treated columns. When sand was used as filler material to mimic sediment conditions, average corrosion rates for Methanobacterium IM1 increased to 0.3 mm/yr (maximum 0.52 mm/yr) with over 83% of the beads having corrosion rates above 0.3 mm/yr. Scanning electron images of metal coupons extracted from the column showed methanogenic cells were clustered close to the metal surface. Methanobacterium IM1 is a hydrogenotrophic methanogen with higher affinity to metal than H2. Unlike SRB, Methanobacterium IM1 is not restricted to the availability of sulfate concentration in the environment. Thus, the use of the multiport flow column provided a new insight on the corrosion potential of methanogens, particularly in dynamic conditions, that offers new opportunities for monitoring and development of mitigation strategies. Overall, this study shows under certain conditions methanogenic archaea can cause higher corrosion than SRB, specific quantifications, i.e., maximum, average, and minimum corrosion rates can be determined, and that spatial statistical evaluations of MIC can be carried out.
KW - Microbiologically influenced corrosion
KW - Methanogen
KW - Methane
KW - Biocorrosion
KW - Flow system
KW - Modeling
KW - Multiport
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506084
DO - https://doi.org/10.3389/fmicb.2020.00527
VL - 11
SP - Article 527
PB - Frontiers in microbiology
AN - OPUS4-50608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Melo Bernardino, Raphael
A1 - Valentino, S.
A1 - Franchin, G.
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Manufacturing of ceramic components with internal channels by a novel additive/subtractive hybridizazion process
N2 - A new approach for fabrication of ceramic components with inner channels is proposed, as a result of the combination of two additive and one subtractive manufacturing processes. In this project, porcelain parts are manufactured by the Layerwise Slurry Deposition (LSD) process, meanwhile end milling and Direct Ink Writing (DIW) are applied to create channels on the surface of the deposited ceramic. Unique to the LSD process is the Formation of a freestanding powder bed with a mechanical strength comparable to conventional slip casted ceramic green bodies. Combining these three processes allows the manufacturing of ceramic objects containing an internal path of ink, which in this case was a graphite-based ink that can be further eliminated by heat treatment to obtain a porcelain object embedded with channels. The results show the capabilities of this method and its potential to fabricate not only parts with inner channels, but also multi-material and multi-functional components (such as integrated electronic circuits).
KW - Additive Manufacturing
KW - Layerwise Slurry Deposition
KW - Hybrid Manufacturing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510012
UR - https://www.sciencedirect.com/science/article/pii/S2666539520300109?via%3Dihub
DO - https://doi.org/10.1016/j.oceram.2020.100010
VL - 2
SP - 100010
PB - Elsevier Ltd.
AN - OPUS4-51001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
A1 - Buggisch, E.
A1 - Schiller, Bernadette Nicole
A1 - Beck, M.
T1 - Corrosion Study on Wellbore Materials for the CO2 Injection Process
N2 - For reliability and safety issues of injection wells, corrosion resistance of materials used needs to be determined. Herein, representative low-cost materials, including carbon steel X70/1.8977 and low alloyed steel 1.7225, were embedded in mortar to mimic the realistic casing-mortar interface. Two types of cement were investigated: (1) Dyckerhoff Variodur commercial Portland cement, representing a highly acidic resistant cement and (2) Wollastonite, which can react with CO2 and become stable under a CO2 stream due to the carbonation process. Exposure tests were performed under 10 MPa and at 333 K in artificial aquifer fluid for up to 20 weeks, revealing crevice corrosion and uniform corrosion instead of expected pitting corrosion. To clarify the role of cement, simulated pore water was made by dispersing cement powder in aquifer fluid and used as a solution to expose steels. Surface analysis, accompanied by element mapping on exposed specimens and their crosssections, was carried out to trace the chloride intrusion and corrosion process that followed.
KW - Carbon capture storage
KW - CCS
KW - Carbon dioxide
KW - Corrosion
KW - Carbon steel
KW - Aquifer fluid
KW - Cement
KW - Casing
KW - Pitting
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519774
DO - https://doi.org/10.3390/pr9010115
SN - 2227-9717
VL - 9
IS - 1
SP - 115
PB - MDPI
CY - Basel
AN - OPUS4-51977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilbig, Janka
A1 - Borges de Oliveira, F.
A1 - Obaton, A.-F.
A1 - Schwentenwein, M.
A1 - Rübner, Katrin
A1 - Günster, Jens
T1 - Defect detection in additively manufactured lattices
N2 - This paper investigates fast and inexpensive measurement methods for defect detection in parts produced by Additive Manufacturing (AM) with special focus on lattice parts made of ceramics. By Lithography-based Ceramic Manufacturing, parts were built both without defects and with typical defects intentionally introduced. These defects were investigated and confirmed by industrial X-ray Computed Tomography. Alternative inexpensive methods were applied afterwards on the parts such as weighing, volume determination by Archimedes method and gas permeability measurement. The results showed, that defects resulting in around 20% of change in volume and mass could be separated from parts free of defects by determination of mass or volume. Minor defects were not detectable as they were in the range of process-related fluctuations. Permeability measurement did not allow to safely identify parts with defects. The measurement methods investigated can be easily integrated in AM process chains to support quality control.
KW - Additive manufacturing
KW - Quality assurance
KW - Defect detection
KW - Lattices
KW - Ceramics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513547
DO - https://doi.org/10.1016/j.oceram.2020.100020
VL - 3
SP - 100020
PB - Elsevier Ltd.
AN - OPUS4-51354
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Schütter, J. D.
A1 - Wagner, R.
A1 - Dimper, M.
A1 - Lützenkirchen-Hecht, D.
A1 - Özcan Sandikcioglu, Özlem
T1 - Trained to corrode: Cultivation in the presence of Fe(III) increases the electrochemical activity of iron reducing bacteria – An in situ electrochemical XANES study
N2 - This paper reports results from in situ electrochemical X-ray absorption near-edge spectroscopy (XANES) studies of the corrosion processes on model thin iron films in the presence of iron reducing bacteria Shewanella putrefaciens. Here we investigate the electrochemical activity of two cultures grown in the presence and absence of Fe(III) citrate in the culture medium. The XANES spectra and the OCP data of the Fe sample incubated with the culture grown in absence of Fe(III) did not show any significant changes during twenty hours of monitoring. In the case of the culture grown in Fe(III) containing medium, an accelerated dissolution of the iron film was observed together with the formation of a mixed Fe(II)-Fe(III) hydroxide surface layer. The open circuit potential (OCP) steadily approached the free corrosion potential of iron in neutral chloride containing electrolytes, indicating a continuous dissolution process without passivation.
KW - Microbiologically influenced corrosion
KW - XANES
KW - Electrochemistry
KW - Iron reducing bacteria
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505732
DO - https://doi.org/10.1016/j.elecom.2020.106673
VL - 112
SP - 106673
PB - Elsevier B.V.
AN - OPUS4-50573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stier, S. P.
A1 - Kreisbeck, C.
A1 - Ihssen, H.
A1 - Popp, M. A.
A1 - Hauch, J.
A1 - Malek, K.
A1 - Reynaud, M.
A1 - Goumans, T.P.M.
A1 - Carlsson, J.
A1 - Todorov, I.
A1 - Gold, L.
A1 - Räder, A.
A1 - Wenzel, W.
A1 - Bandesha, S. T.
A1 - Jacques, P.
A1 - Garcia‐Moreno, F.
A1 - Arcelus, O.
A1 - Friederich, P.
A1 - Clark, S.
A1 - Maglione, M.
A1 - Laukkanen, A.
A1 - Castelli, I. E.
A1 - Carrasco, J.
A1 - Cabanas, M. C.
A1 - Stein, H. S.
A1 - Özcan Sandikcioglu, Özlem
A1 - Elbert, D.
A1 - Reuter, K.
A1 - Scheurer, C.
A1 - Demura, M.
A1 - Han, S. S.
A1 - Vegge, T.
A1 - Nakamae, S.
A1 - Fabrizio, M.
A1 - Kozdras, M.
T1 - Materials Acceleration Platforms (MAPs) Accelerating Materials Research and Development to Meet Urgent Societal Challenges
N2 - AbstractClimate Change and Materials Criticality challenges are driving urgent responses from global governments. These global responses drive policy to achieve sustainable, resilient, clean solutions with Advanced Materials (AdMats) for industrial supply chains and economic prosperity. The research landscape comprising industry, academe, and government identified a critical path to accelerate the Green Transition far beyond slow conventional research through Digital Technologies that harness Artificial Intelligence, Smart Automation and High Performance Computing through Materials Acceleration Platforms, MAPs. In this perspective, following the short paper, a broad overview about the challenges addressed, existing projects and building blocks of MAPs will be provided while concluding with a review of the remaining gaps and measures to overcome them.
KW - Advanced materials
KW - Artificial intelligence
KW - Autonomous labs
KW - Materials acceleration platforms
KW - Societal challenges
KW - MAPs
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611583
DO - https://doi.org/10.1002/adma.202407791
SP - 1
EP - 26
PB - Wiley
AN - OPUS4-61158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sänger, Johanna
A1 - Riechers, Birte
A1 - Pauw, Brian Richard
A1 - Günster, Jens
T1 - Transparent feedstocks for photon-based additve manufacturing technologies for powder processing of ceramics
N2 - Photon-based additive manufacturing technologies such as SLA, DLP, LCM, moreover volumetric two-photon-polymerization, Xolography and holographic technologies promise the highest accuracy and dimensional freedom. But to transfer the light through the feedstock it needs sufficient transparency at the used light wavelength. Ceramic particles used for powder processing routes act as scattering sites and therefore hinder the light transmission, unless…
The particle size and particle size distribution are chosen small and narrow enough. Particles which are smaller than roughly 1/10th of the light wavelength, mostly nanoparticles around 5nm size, decrease scattering vastly. This turns resins even with homogeneously distributed ceramic weight fraction of up to 80% transparent again. Feedstocks could be prepared for the highly accurate two-photon-polymerization gaining the smallest yttria stabilized zirconia structures with a resolution of 500nm and unique mechanical properties. The same feedstocks could be applied to DLP and LCM as layer-by-layer AM-technologies for bigger parts. Hybridizing both technologies lead to ceramic parts with microscopic accuracy at macroscopic dimensions. The feedstock was even applied to the volumetric Xolography with the highest transparency requirement so far and to versatile and flexible holographic AM.
Highly filled nano-particle containing transparent ceramic feedstocks open the way for technical ceramics in high precision manufacturing where the performance and durability and accessibility are increased and created by the unique ceramic properties such as mechanical strength, chemical and thermal resistance and biocompatibility
T2 - 14th International Conference on Ceramic Materials and Components for Energy and Environmental Systems
CY - Budapest, Hungary
DA - 18.08.2024
KW - Transparent
KW - Ceramic
KW - Additive manufacturing
PY - 2024
AN - OPUS4-60891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czerski, Jakub
A1 - Mitoraj-Krolikowska, Marzena
A1 - Godlewska, Elzbieta
A1 - Wetzel, Annica
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
A1 - Marzec, Mateusz
A1 - Goly, Marcin
T1 - Corrosion and passivation of AlCrFe2Ni2Mox high-entropy alloys in sulphuric acid
N2 - Corrosion behaviour of AlCrFe2Ni2Mox (x = 0.0, 0.1, 0.15, 0.3 and 0.6) high-entropy alloys was investigated in a 0.1 M H2SO4 solution. Passive films formed upon anodic polarisation, built of Al-based inner layer and (Cr, Fe, Mo)-based outer layer, had good protective properties. In particular, they prevented corrosion of the (Al, Ni)-rich BCC-B2 phase, which was observed under open-circuit conditions. Moderate amounts of Mo, up to x = 0.3, positively affected the passivation ability of AlCrFe2Ni2. Significant changes in microstructure and phase composition of the alloy at higher Mo concentrations (x = 0.6) resulted in deterioration of its corrosion resistance.
KW - EIS
KW - Alloy
KW - Sulphuric acid
KW - AFM
KW - Acid corrosion
KW - Passive films
PY - 2024
DO - https://doi.org/10.1016/j.corsci.2024.111855
SN - 0010-938X
VL - 229
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-59703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kratzig, A.
A1 - Le, Quynh Hoa
A1 - Bettge, Dirk
A1 - Menneken, M.
A1 - Bäßler, Ralph
T1 - Early Stage of Corrosion Formation on Pipeline Steel X70 Under Oxyfuel Atmosphere at Low Temperature
N2 - The early stage of corrosion formation on X70 pipeline steel under oxyfuel atmosphere was investigated by applying a simulated gas mixture (CO2 containing 6700 ppmv O2, 100 ppmv NO2, 70 ppmv SO2 and 50 ppmv H2O) for 15 h at 278 K and ambient pressure. Short-term tests (6 h) revealed that the corrosion starts as local spots related to grinding marks progressing by time and moisture until a closed layer was formed. Acid droplets (pH 1.5), generated in the gas atmosphere, containing a mixture of H2SO4 and HNO3, were identified as corrosion starters. After 15 h of exposure, corrosion products were mainly X-ray amorphous and only partially crystalline. In-situ energy-dispersive X-ray diffraction (EDXRD) results showed that the crystalline fractions consist primarily of water-bearing iron sulfates. Applying Raman spectroscopy, water-bearing iron nitrates were detected as subordinated phases. Supplementary long-term tests exhibited a significant increase in the crystalline fraction and formation of additional water-bearing iron sulfates. All phases of the corrosion layer were intergrown in a nanocrystalline network. In addition, numerous globular structures have been detected above the corrosion layer, which were identified as hydrated iron sulphate and hematite. As a type of corrosion, shallow pit formation was identified, and the corrosion rate was about 0.1 mma−1. In addition to in-situ EDXRD, SEM/EDS, TEM, Raman spectroscopy and interferometry were used to chemically and microstructurally analyze the corrosion products.
KW - Corrosion
KW - CCUS
KW - In-situ ED-XRD
KW - CO2 pipeline transport
KW - Oxyfuel
KW - Carbon steel
KW - Impurities
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506303
DO - https://doi.org/10.3390/pr8040421
SN - 2227-9717
VL - 8
IS - 4
SP - 421-1
EP - 421-19
PB - MDPI
CY - Basel
AN - OPUS4-50630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hattrick-Simpers, J.
A1 - Li, K.
A1 - Greenwood, M.
A1 - Black, R.
A1 - Witt, Julia
A1 - Kozdras, M.
A1 - Pang, X.
A1 - Özcan Sandikcioglu, Özlem
T1 - Designing durable, sustainable, high-performance materials for clean energy infrastructure
N2 - Civilization and modern societies would not be possible without manmade materials. Considering their production volumes, their supporting role in nearly all industrial processes, and the impact of their sourcing and production on the environment, metals and alloys are and will be of prominent importance for the clean energy transition. The focus of materials discovery must move to more specialized, application-tailored green alloys that outperform the legacy materials not only in performance but also in sustainability and resource efficiency. This white paper summarizes a joint Canadian-German initiative aimed at developing a materials acceleration platform (MAP) focusing on the discovery of new alloy families that will address this challenge. We call our initiative the “Build to Last Materials Acceleration Platform” (B2L-MAP) and present in this perspective our concept of a three-tiered self-driving laboratory that is composed of a simulation-aided pre-selection module (B2L-select), an artificial intelligence (AI)-driven experimental lead generator (B2L-explore), and an upscaling module for durability assessment (B2L-assess). The resulting tool will be used to identify and subsequently demonstrate novel corrosion-resistant alloys at scale for three key applications of critical importance to an offshore, wind-driven hydrogen plant (reusable electrical contacts, offshore infrastructure, and oxygen evolution reaction catalysts).
KW - Material Acceleration Platforms (MAPs)
KW - Self-driving-labs (SDLs)
KW - Automation
KW - Artificial Intelligence (AI)
KW - Elektrolyse
KW - Structural Materials
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568452
DO - https://doi.org/10.1016/j.xcrp.2022.101200
SN - 2666-3864
VL - 4
IS - 1
SP - 1
EP - 11
PB - Cell Press ; Elsevier
CY - Maryland Heights, MO
AN - OPUS4-56845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Aristia, Gabriela
A1 - Bäßler, Ralph
T1 - A Coating System for Corrosion Protection of Carbon Steel as an Alternative for High Alloyed Materials
N2 - Corrosive geothermal brines are a major challenge to geothermal power-plants. For cost reasons, plant designers favorize low alloyed steels, e.g., carbon steel, which are susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic and saline properties. To solve such problem, coatings or inhibitors would be a protective solution as an alternative to the use of high alloyed materials.
This study investigated a coating system consisting of polyaniline/silicon dioxide basing on locally available resources. Protection against corrosion of carbon steel is shown by long-term exposure and electrochemical tests of coated carbon steels, performed in an artificial acidic and saline geothermal brine, comparable to real conditions at a site in Indonesia.
Therefore, an integrated coating system is presented for corrosion protection, combining the electro-chemical functionality of polyaniline and the physical advantages of silica.
T2 - European Geothermal Congress
CY - Berlin, Germany
DA - 17.10.22
KW - Corrosion
KW - Geothermal
KW - Coatings
KW - Polyaniniline
KW - Silicate
PY - 2022
SP - 1
EP - 7
CY - Berlin
AN - OPUS4-56085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sediqi, Salmin
T1 - Multi-principal element alloy nanoparticle (MPEA-NP) electrocatalysts prepared by pulsed laser ablation for electroreduction of CO2
N2 - Multi-principal element alloy (MPEA) nanoparticle electrocatalysts have the potential to provide a cost-effective and efficient alternative to noble metal electrocatalysts. The chemically complex nature and the high configurational entropy of MPEAs offer advantages in tailoring catalytic activity, product selectivity, and improved stability under harsh reaction conditions. Cu-containing bimetallic catalyst systems have already been demonstrated to lead to a significant increase in catalytic efficiency compared to monometallic systems. Thus, this project aims at the design of Cu-containing MPEAs and nanoparticle electrocatalysts for carbon dioxide reduction reaction.
In this project, base alloys were prepared by means of arc melting with subsequent homogenization treatments and processed by pulsed laser ablation in water and organic solvents into high-purity nanoparticles. The nanoparticles were characterized by means of transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). Electrochemical testing was performed both on bulk alloy samples and nanoparticle film coated glassy carbon electrodes by means of cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Nanoparticle coated electrodes have been investigated by means of atomic force microscopy (AFM) and scanning kelvin probe force microscopy (SKPFM) to assure a homogeneous distribution on the electrode surface. The presentation will summarize our initial results on the electrocatalytic activity of Cu-MPEA system for carbon dioxide reduction.
T2 - OPERANDO SPM 2023
CY - Berlin
DA - 15.11.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Electrocatalysis
PY - 2023
AN - OPUS4-59402
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pomorska Gawel, A.
A1 - Dąbkowska, M.
A1 - Kosior, D.
A1 - Batys, P.
A1 - Szatanik, A.
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
A1 - Michna, A.
T1 - Multiscale insights into fibroblast growth factor 23 adsorption on polyelectrolyte layers: From molecular properties to biointerfaces
N2 - Fibroblast growth factor 23 (FGF23) is a clinically significant protein hormone regulating phosphate and vitamin D metabolism, with elevated levels linked to chronic kidney disease, cardiovascular disorders, and impaired bone homeostasis. Despite its relevance as both a biomarker and a therapeutic target, its interactions with functional biomaterials remain poorly understood. In this work, we investigate the FGF23 adsorption on polyelectrolyte layers using a combination of theoretical modeling and experimental methods. Theoretical calculations provided insights into the protein's charge distribution and diffusion properties, while experimental measurements quantified its hydrodynamic diameter, electrophoretic mobility, and electrokinetic charge over a broad range of pH values. Microscale thermophoresis revealed quantitative binding affinities of FGF23 to hyaluronic acid, chitosan, and poly(diallyldimethylammonium chloride). Adsorption studies on mica, silica, and polyelectrolyte mono- and bilayers showed that FGF23 binds to both negatively and positively charged substrates, with binding affinities following: hyaluronic acid < poly(diallyldimethylammonium chloride) < chitosan. Desorption occurred more readily from negatively charged surfaces (mica, silica and hyaluronic acid), indicating weaker interactions compared to positively charged layers. These results reveal fundamental aspects of protein –polyelectrolyte interactions and highlight the reversible binding capacity of FGF23 to negatively charged surfaces. Such adsorption behavior provides a physicochemical framework for considering FGF23-polyelectrolyte systems in the design of therapeutic carriers and bioactive materials. However, any direct relevance to wound healing, chronic kidney disease, or cardiovascular disorders remains prospective and requires dedicated biological validation.
KW - Molecular dynamics
KW - Streaming potential measurements
KW - Adsorption
KW - Stability
KW - Binding affinity
PY - 2026
DO - https://doi.org/10.1016/j.ijbiomac.2026.150221
SN - 0141-8130
VL - 341
IS - Part 1
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-65415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bender, R.
A1 - Féron, D.
A1 - Mills, D.
A1 - Ritter, S.
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
A1 - de Graeve, I.
A1 - Dugstad, A.
A1 - Grassini, S.
A1 - Hack, T.
A1 - Halama, M.
A1 - Han, E.-H.
A1 - Harder, T.
A1 - Hinds, G.
A1 - Kittel, J.
A1 - Krieg, R.
A1 - Leygraf, C.
A1 - Martinelli, L.
A1 - Mol, A.
A1 - Neff, D.
A1 - Nilsson, J.-O.
A1 - Odnevall, I.
A1 - Paterson, S.
A1 - Paul, S.
A1 - Prošek, T.
A1 - Raupach, M.
A1 - Revilla, R. I.
A1 - Ropital, F.
A1 - Schweigart, H.
A1 - Szala, E.
A1 - Terryn, H.
A1 - Tidblad, J.
A1 - Virtanen, S.
A1 - Volovitch, P.
A1 - Watkinson, D.
A1 - Wilms, M.
A1 - Winning, G.
A1 - Zheludkevich, M.
T1 - Corrosion challenges towards a sustainable society
N2 - A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate‐resilient energy systems and infrastructures brings with it a long‐term direction, so as a result the long‐term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics.
KW - Corrosion
KW - Corrosion costs
KW - Corrosion protection
KW - Preventive strategies
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554801
DO - https://doi.org/10.1002/maco.202213140
SN - 1521-4176
VL - 73
IS - 11
SP - 1730
EP - 1751
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, Juan-Carlos
A1 - Facchini, Leonardo
A1 - Wilbig, Janka
A1 - Zocca, Andrea
A1 - Stoll, Enrico
A1 - Günster, Jens
T1 - Melt Pool Stability during Local Laser Melting of Lunar Regolith with Large Laser Spots and Varying Gravity
N2 - In order to increase the sustainability of future lunar missions, techniques for in-situ resource utilization (ISRU) must be developed. In this context, the local melting of lunar dust (regolith) by laser radiation for the production of parts and larger structures was investigated in detail. With different experimental setups in normal and microgravity, laser spots with diameters from 5 mm to 100 mm were realized to melt the regolith simulant EAC-1A and an 80%/20% mixture of TUBS-T and TUBS-M, which are used as a substitute for the actual lunar soil. In the experiments performed, the critical parameters are the size of the laser spot, the velocity of the laser spot on the surface of the powder bed, the gravity and the wettability of the powder bed by the melt. The stability of the melt pool as a function of these parameters was investigated and it was found that the formation of a stable melt pool is determined by gravity for large melt pool sizes in the range of 50 mm and by surface tension for small melt pool sizes in the range of a few mm.
KW - Additive Manufacturing
KW - Regolith
KW - Laser melting
KW - ISRU
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639621
DO - https://doi.org/10.1016/j.amf.2025.200227
SN - 2950-4317
VL - 4
IS - 3
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-63962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Orlov, Nikolai
A1 - Kiseleva, A. K.
A1 - Milkini, P. A.
A1 - Evdokimov, P. V.
A1 - Putlayev, V. I.
A1 - Günster, Jens
T1 - Potentialities of Reaction Sintering in the Fabrication of High-Strength Macroporous Ceramics Based on Substituted Calcium Phosphate
N2 - Calcium alkali metal (potassium and sodium) double and triple phosphates have been synthesized in different ways. Was for the first time used reaction sintering to produce ceramics based on calcium alkali metal mixed phosphates and investigated the densification behavior of mixed phosphate-based multiphase materials during sintering by this method. Was presented the microstructure of polished surfaces of sintered samples differing in phase composition and determined the density of ceramics prepared using reaction mixtures differing in composition. The effect of reaction sintering on the porosity of the ceramics has been assessed. Using stereolithographic printing and reaction sintering, was produced macroporous mixed Calcium phosphate-based ceramic implants. Their compressive strength has been determined to be 0.78 ± 0.21 MPa for two-phase samples and 1.02 ± 0.13 MPa for three-phase samples.
KW - Reaction Sintering
KW - Bio Ceramics
PY - 2020
DO - https://doi.org/10.1134/s0020168520120146
VL - 56
IS - 12
SP - 1298
EP - 1306
PB - Pleiades Publishing LTD
AN - OPUS4-52004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diener, S.
A1 - Zocca, Andrea
A1 - Günster, Jens
T1 - Literature review: Methods for achieving high powder bed densities in ceramic powder bed based additive manufacturing
N2 - In additive manufacturing the powder bed based processes binder jetting and powder bed fusion are increasingly used also for the production of ceramics. Final part properties depend to a high percentage on the powder bed density. Therefore, the aim is to use the best combination of powder deposition method and powder which leads to a high packing of the particles. The influence of flowability, powder properties and deposition process on the powder bed density is discussed and the different deposition processes including slurry-based ones are reviewed.
It turns out that powder bed density reached by slurry-based layer deposition exceeds conventional powder deposition, however, layer drying and depowdering are extra steps or more time-consuming for the slurry route.
Depending on the material properties needed the most suitable process for the part has to be selected.
KW - Additive Manufacturing
KW - Powder-based processes
KW - Powder bed density
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534992
DO - https://doi.org/10.1016/j.oceram.2021.100191
VL - 8
SP - 100191
PB - Elsevier Ltd.
AN - OPUS4-53499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michna, A.
A1 - Maciejewska-Prończuk, J.
A1 - Wasilewska, M.
A1 - Kilicer, Tayfun
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
T1 - Effect of the Anchoring Layer and Transport Type on the Adsorption Kinetics of Lambda Carrageenan
N2 - The kinetics of lambda carrageenan (λ-car) adsorption/desorption on/from anchoring layers under diffusion- and convection-controlled transport conditions were investigated. The eighth generation of poly(amidoamine) dendrimers and branched polyethyleneimine possessing different shapes and polydispersity indexes were used for anchoring layer formation. Dynamic light scattering, electrophoresis, streaming potential measurements, optical waveguide lightmode spectroscopy, and quartz crystal microbalance were applied to characterize the formation of mono- and bilayers. The unique combination of the employed techniques enabled detailed insights into the mechanism of the λ-car adsorption mainly controlled by electrostatic interactions. The results show that the macroion adsorption efficiency is strictly correlated with the value of the final zeta potentials of the anchoring layers, the transport type, and the initial bulk concentration of the macroions. The type of the macroion forming the anchoring layer had a minor impact on the kinetics of λ-car adsorption. Besides significance to basic science, the results presented in this paper can be used for the development of biocompatible and stable macroion multilayers of well-defined electrokinetic properties and structure.
KW - AFM
KW - Dynamic light scattering
KW - Electrophoresis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540546
DO - https://doi.org/10.1021/acs.jpcb.1c03550
VL - 125
IS - 28
SP - 7797
EP - 7808
PB - American Chemical Society
AN - OPUS4-54054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cestari, F.
A1 - Yang, Y.
A1 - Wilbig, Janka
A1 - Günster, Jens
A1 - Motta, A.
A1 - Sglavo, V.
T1 - Powder 3D printing of bone scaffolds with uniform and gradient pore sizes using cuttlebone-derived calcium phosphate and glass-ceramic
N2 - The pore geometry of bone scaffolds has a major impact on their cellular response; for this reason, 3D printing is an attractive technology for bone tissue engineering, as it allows for the full control and design of the porosity. Calcium phosphate materials synthesized from natural sources have recently attracted a certain interest because of their similarity to natural bone, and they were found to show better bioactivity than synthetic compounds. Nevertheless, these materials are very challenging to be processed by 3D printing due to technological issues related to their nanometric size. In this work, bone scaffolds with different pore geometries, with a uniform size or with a size gradient, were fabricated by binder jetting 3D printing using a biphasic calcium phosphate (BCP) nanopowder derived from cuttlebones. To do so, the nanopowder was mixed with a glass-ceramic powder with a larger particle size (45–100 µm) in 1:10 weight proportions. Pure AP40mod scaffolds were also printed. The sintered scaffolds were shown to be composed mainly by hydroxyapatite (HA) and wollastonite, with the amount of HA being larger when the nanopowder was added because BCP transforms into HA during sintering at 1150 ◦C. The addition of bio-derived powder increases the porosity from 60% to 70%, with this indicating that the nanoparticles slow down the glass-ceramic densification. Human mesenchymal stem cells were seeded on the scaffolds to test the bioactivity in vitro. The cells’ number and metabolic activity were analyzed after 3, 5 and 10 days of culturing.
The cellular behavior was found to be very similar for samples with different pore geometries and compositions. However, while the cell number was constantly increasing, the metabolic activity on the scaffolds with gradient pores and cuttlebone-derived powder decreased over time, which might be a sign of cell differentiation. Generally, all scaffolds promoted fast cell adhesion and proliferation, which were found to penetrate and colonize the 3D porous structure.
KW - Bioactivity
KW - Cuttlefish
KW - Biphasic calcium phosphate
KW - Binder jetting
KW - Scaffold geometry
KW - Hausner ratio
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553627
DO - https://doi.org/10.3390/ma15155139
SN - 1996-1944
VL - 15
IS - 15
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55362
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Chayanika
A1 - Kastania, Eleni
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
T1 - Corrosion protection properties of poly(4-vinyl pyridine) containing multilayer polymeric coatings on magnesium alloy AZ31
N2 - The aim of this study is to develop polymeric thin films for corrosion protection of magnesium alloy AZ31. As polymer matrix, poly(4-vinyl pyridine) (P4VP) is selected due to its semiconducting properties and protonic conductivity. Polyacrylic acid is tested as crosslinking layers to improve interfacial adhesion. The macroscopic corrosion properties of the multilayer coatings are investigated by means of electrochemical methods, such as linear sweep voltammetry and electrochemical impedance spectroscopy (EIS), in corrosive media simulating technical and biomedical applications. It is demonstrated that thin multilayer coatings can suppress the corrosion rates of magnesium alloys. To our best knowledge, this is the first demonstration of the use of P4VP as a conducting polymer film with protonic conductivity for corrosion protection of magnesium alloys.
KW - Multilayercoatings
KW - AZ31
KW - Corrosion protection
KW - Intrinsically conducting polymers
KW - Magnesium alloys
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551799
DO - https://doi.org/10.1002/maco.202112708
SN - 0947-5117
VL - 73
IS - 3
SP - 427
EP - 435
PB - Wiley VHC-Verlag
AN - OPUS4-55179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chi, J.
A1 - Agea Blanco, B.
A1 - Bruno, Giovanni
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Self-Organization Postprocess for Additive Manufacturingin Producing Advanced Functional Structure and Material
N2 - Additive manufacturing (AM) is developing rapidly due to itsflexibility in producing complex geometries and tailored material compositions. However, AM processes are characterized by intrinsic limitations concerning their resolution and surface finish, which are related to the layer-by-layer stacking process. Herein, a self-organization process is promoted as an approach to improve surface quality and achieve optimization of 3D minimal surface lightweight structures. The self-organization is activated after the powder bed 3D printing process via local melting, thereby allowing surface tension-driven viscous flow.The surface roughness Ra (arithmetic average of the roughness profile) could bedecreased by a factor of 1000 and transparent lenses and complex gyroid structures could be produced for demonstration. The concept of self-organization is further elaborated by incorporating external magnetic fields to intentionally manipulate magnetic particles, which are mixed with the polymer before printing and self-organization. This concept can be applied to develop programmable materials with specific microtextures responding to the external physical conditions.
KW - Additive Manufacturing
KW - Self-organization
KW - Triply Periodical Minimal Surface
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540588
DO - https://doi.org/10.1002/adem.202101262
VL - 24
IS - 6
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-54058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stinville, J.C.
A1 - Charpagne, M.A.
A1 - Maaß, Robert
A1 - Proudhon, H.
A1 - Ludwig, W.
A1 - Callahan, P.G.
A1 - Wang, F.
A1 - Beyerlein, I.J.
A1 - Echlin, M.P.
A1 - Pollock, T.M.
T1 - Insights into Plastic Localization by Crystallographic Slip from Emerging Experimental and Numerical Approaches
N2 - Advanced experimental and numerical approaches are being developed to
capture the localization of plasticity at the nanometer scale as a function of the multiscale and heterogeneous microstructure present in metallic materials.
These innovative approaches promise new avenues to understand microstructural effects on mechanical properties, accelerate alloy design, and enable more accurate mechanical property prediction. This article provides an overview of emerging approaches with a focus on the localization of plasticity by crystallographic slip. New insights into the mechanisms and mechanics of strain localization are addressed. The consequences of the localization of plasticity by deformation slip for mechanical properties of metallic materials are also detailed.
KW - Slip localization
KW - Metallic materials
KW - Experimental and numerical techniques
KW - Mechanical properties
KW - Plasticity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578398
DO - https://doi.org/10.1146/annurev-matsci-080921-102621
SN - 1531-7331
VL - 53
SP - 275
EP - 317
AN - OPUS4-57839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mendive-Tapia, E.
A1 - Neugebauer, J.
A1 - Hickel, Tilmann
T1 - Ab initio calculation of the magnetic Gibbs free energy of materials using magnetically constrained supercells
N2 - We present a first-principles approach for the computation of the magnetic Gibbs free energy ofmaterials using magnetically constrained supercell calculations. Our approach is based on an adiabatic approximation of slowly varying local moment orientations, the so-called finite-temperature disordered local moment picture. It describes magnetic phase transitions and how electronic and/or magnetostructural mechanisms generate a discontinuous (first-order) character. We demonstrate that the statistical mechanics of the local moment orientations can be described by an affordable number of supercell calculations containing noncollinear magnetic configurations.
The applicability of our approach is illustrated by firstly studying the ferromagnetic state in bcc Fe. We then investigate the temperature-dependent properties of a triangular antiferromagnetic state stabilizing in two antiperovskite systems Mn3AN (A = Ga, Ni). Our calculations provide the negative thermal expansion of These materials as well as the ab initio origin of the discontinuous character of the phase transitions, electronic and/or magnetostructural, in good agreement with experiment.
KW - Ab initio
KW - Thermodynamics
KW - Magnetic alloys
KW - Phase transformations
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543710
DO - https://doi.org/10.1103/PhysRevB.105.064425
SN - 2469-9969
VL - 105
IS - 6
SP - 1
EP - 6
PB - American Institute of Physics
CY - Woodbury, NY
AN - OPUS4-54371
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sözen, H.I.
A1 - Ener, S.
A1 - Maccari, F.
A1 - Fayyazi, B.
A1 - Gutfleisch, O.
A1 - Neugebauer, J.
A1 - Hickel, Tilmann
T1 - Combined ab initio and experimental screening of phase stabilities in the Ce-Fe-Ti-X system (X = 3d and 4d metals)
N2 - One of the main challenges for the synthesis and application of the promising hard-magnetic compound CeFe11Ti is the formation of Laves phases that are detrimental for their thermodynamic stability and magnetic properties. In this paper, we present an ab initio based approach to modify the stability of these phases in the Ce-Fe-Ti system by additions of 3d and 4d elements. We combine highly accurate free-energy calculations with an efficient screening technique to determine the critical annealing temperature for the formation of Ce(Fe,X)11Ti. The central findings are the dominant role of the formation enthalpy at T = 0 K on chemical trends and the major relevance of partial chemical decompositions. Based on these insights, promising transition metals to promote the stability of the hard-magnetic phase, such as Zn and Tc, were predicted. The comparison with suction casting and reactive crucible melting experiments for Ce-Fe-Ti-X (X = Cu, Ga, Co, and Cr) highlights the relevance of additional phases and quaternary elements.
KW - Density functional theory
KW - Phase stability
KW - Energy materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568850
DO - https://doi.org/10.1103/PhysRevMaterials.7.014410
SN - 2475-9953
VL - 7
SP - 1
EP - 15
AN - OPUS4-56885
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Ni, H.C.
A1 - Chakraborty, A.
A1 - Ghassemi-Armaki, H.
A1 - Zuo, J.M.
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - Segregation-induced grain-boundary precipitation during early stages of liquid-metal embrittlement of an advanced high-strength steel
N2 - Liquid-metal embrittlement (LME) of galvanized (Zn-coated) advanced high-strength steels is a long-known problem in materials science. Here we reveal the initial microstructural processes underneath the Zn-coating that lead to LME-microcrack initiation in the steel substrate. We track the microstructural evolution during the first tens of milliseconds and find pronounced signatures of Fe-Zn intermetallic precipitation in both ferrite grain boundaries and at internal ferrite-oxide phase boundaries. In concert with novel CALPHAD-integrated density-based thermodynamic modelling, we demonstrate that Zn-rich intermetallic phase-nucleation can occur at markedly low processing temperatures due to a segregation transition. We show that a small Znenrichment caused by Zn bulk-diffusion during the initial temperature rise in a joining process is sufficient to induce the segregation transition and subsequent nucleation of Fe-Zn intermetallic grain-boundary phases, which the experiments link to crack initiation sites. These findings direct focus onto LME-controlling microstructural and thermodynamic phenomena at temperatures below the ductility trough and the austenite formation temperature.
KW - Resistance spot welding
KW - Liquid-metal embrittlement
KW - Steels
KW - Grain boundaries
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581067
DO - https://doi.org/10.1016/j.actamat.2023.119243
VL - 259
SP - 1
EP - 12
PB - Elsevier Ltd
AN - OPUS4-58106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rizzardi, Q.
A1 - McElfresh, C.
A1 - Sparks, G.
A1 - Stauffer, D.
A1 - Marian, J.
A1 - Maaß, Robert
T1 - Mild-to-wild plastic transition is governed by athermal screw dislocation slip in bcc Nb
N2 - Plastic deformation in crystals is mediated by the motion of line defects known as dislocations.
For decades, dislocation activity has been treated as a homogeneous, smooth continuous process. However, it is now recognized that plasticity can be determined by longrange correlated and intermittent collective dislocation processes, known as avalanches. Here we demonstrate in body-centered cubic Nb how the long-range and scale-free dynamics at room temperature are progressively quenched out with decreasing temperature, eventually revealing intermittency with a characteristic length scale that approaches the Burgers Vector itself. Plasticity is shown to be bimodal across the studied temperature regime, with conventional thermally-activated smooth plastic flow (‘mild’) coexisting with sporadic Bursts (‘wild’) controlled by athermal screw dislocation activity, thereby violating the classical Notion of temperature-dependent screw dislocation motion at low temperatures. An abrupt increase of the athermal avalanche component is identified at the critical temperature of the material.
Our results indicate that plasticity at any scale can be understood in terms of the coexistence of these mild and wild modes of deformation, which could help design better alloys by suppressing one of the two modes in desired temperature Windows.
KW - Plastic deformation
KW - Microplastic stress
KW - Intermittent microplasticity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543927
DO - https://doi.org/10.1038/s41467-022-28477-4
VL - 13
IS - 1
SP - 1
EP - 9
PB - Nature
AN - OPUS4-54392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sözen, H.I.
A1 - Mendive-Tapia, E.
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
T1 - Ab initio investigations of point and complex defect structures in B2-FeAl
N2 - We study single-site and two-site defect structures in B2-type Fe-Al alloys by means of density functional theory supercell calculations. The defect formation energies are calculated as functions of the chemical potential, which are used to obtain the dependence of the defect concentrations on Al content at different temperatures. We also examine the converging behavior of the formation energies with respect to the supercell size to study the corresponding limit of dilute defects. The effect of magnetism is investigated by considering nonmagnetic, ferromagnetic, and paramagnetic states, calculations for the latter showing that the magnitude of the local magnetic moments strongly impacts the defect formation energies. The methodological studies are used to provide explanations for the wide spread of defect formation energies reported by experiments and other theoretical investigations. Based on these insights, the stability of the B2-FeAl structure as a function of Al concentration is obtained and discussed.
KW - Atomistic models
KW - Defects
KW - Thermodynamics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546956
DO - https://doi.org/10.1103/PhysRevMaterials.6.023603
SN - 2475-9953
VL - 6
IS - 2
SP - 1
EP - 11
PB - APS
CY - College Park, MD
AN - OPUS4-54695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tielemann, Christopher
A1 - Reinsch, Stefan
A1 - Maaß, Robert
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal nucleation tendency and crystal surface energy obtained from bond energies and crystal lattice data
N2 - We present an easy-to-apply method to predict structural trends in the internal nucleation tendency of oxide glasses. The approach is based on calculated crystal fracture surface energies derived from easily accessible diatomic bond energy and crystal lattice data. The applicability of the method is demonstrated on literature nucleation data for isochemically crystallizing oxide glasses.
KW - Glass
KW - Nucleation tendency
KW - Fracture surface energy
KW - Crystal lattice
KW - Bond energy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548814
DO - https://doi.org/10.1016/j.nocx.2022.100093
SN - 2590-1591
VL - 14
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-54881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Ning
A1 - Hammerschmidt, Thomas
A1 - Hickel, Tilmann
A1 - Rogal, Jutta
A1 - Drautz, Ralf
T1 - Influence of spin fluctuations on structural phase transitions of iron
N2 - The effect of spin fluctuations on the α(bcc)-γ(fcc)-δ(bcc) structural phase transitions in iron is investigated with a tight-binding (TB) model. The orthogonal d-valent TB model is combined with thermodynamic integration, spin-space averaging, and Hamiltonian Monte Carlo to compute the temperature-dependent free-energy difference between bcc and fcc iron. We demonstrate that the TB model captures experimentally observed phonon spectra of bcc iron at elevated temperatures. Our calculations show that spin fluctuations are crucial for both the α−γ and γ−δ phase transitions but they enter through different mechanisms. Spin fluctuations impact the α−γ phase transition mainly via the magnetic/electronic free-energy difference between bcc and fcc iron. The γ−δ phase transition, in contrast, is influenced by spin fluctuations only indirectly via the spin-lattice coupling. Combining the two mechanisms, we obtain both the α−γ and γ−δ phase transitions with our TB model. The calculated transition temperatures are in very good agreement with experimental values.
KW - Structural phase transition
KW - Magnetism
KW - Spin-lattice coupling
PY - 2023
DO - https://doi.org/10.1103/PhysRevB.107.104108
SN - 2469-9950
VL - 107
IS - 10
SP - 1
EP - 9
PB - American Physical Society (APS)
AN - OPUS4-58790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Seamless Science in Platform MaterialDigital (PMD): Demonstration of Semantic Data Integration as Good Practices
N2 - Following the new paradigm of materials development, design, and optimization, digitalization is the main goal in materials sciences and engineering (MSE) which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web technologies (SWT) are used since they allow for machine-actionable and human-readable knowledge representations needed for data management, retrieval, and (re)use.
The project ‘platform MaterialDigital’ (PMD) aims to bring together and support interested parties from both industrial and academic sectors in a sustainable manner in solving digitalization tasks and implementing digital solutions. Therefore, the establishment of a virtual material data space and the systematization of the handling of hierarchical, process-dependent material data are focused. Core points to be dealt with are the development of agreements on data structures and interfaces implemented in distinct software tools and to offer users specific support in their projects. Furthermore, the platform contributes to a standardized description of data processing methods in materials research. In this respect, selected MSE methods are semantically represented on a prototypical basis which are supposed to serve as best practice examples with respect to knowledge representation and the creation of knowledge graphs used for material data.
Accordingly, this poster presentation illustrates demonstrators developed and deployed within the PMD project. Semantically anchored using the mid-level PMD Core Ontology (PMDco), they address data transformation leading to a novel data management which is based on semantic integrated data. The PMD data acquisition pipeline (DAP), which is fueled by traditional, diverse data formats, and a pipeline applying an electronic laboratory notebook (ELN) as data source are displayed. Additionally, the efficient combination of diverse datasets originating from different sources is demonstrated by the representation of a use case dealing with the well-known Orowan relation.
T2 - Materials Science and Engineering Congress 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Demonstrators
PY - 2024
AN - OPUS4-61136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holzer, Marco
A1 - Johansen, Sidsel M.
A1 - Christensen, Johan F.S.
A1 - Smedskjaer, Morten M.
A1 - Cicconi, Maria Rita
A1 - de Ligny, Dominique
A1 - Müller, Ralf
A1 - de Camargo, Andrea S.S.
A1 - Maaß, Robert
T1 - Direct connection between secondary relaxation mode and fracture toughness in alkali-aluminosilicate glasses
N2 - Oxide glasses are intrinsically brittle, lacking sufficient atomic-scale mechanisms that can relax mechanical stresses in the vicinity of a propagating crack. As a result, fracture is typically well-captured by considering local bond rupture at the crack tip. Here we demonstrate that barrier energies related to the low-temperature 𝛾-relaxation mode in alkali-aluminosilicate glasses are inversely related to the fracture toughness measured via standardized three-point bending fracture experiments. This holds true for both a series with varying cations (Li, Na, K) and one with varying Li concentration. The structural rationale for this finding is gained via Raman spectroscopy. The findings suggest that a fundamental structural relaxation mode measured on bulk specimens can serve as an effective guideline for fracture toughness of oxide glasses. Data for additional silicate glasses support this conclusion.
KW - Fracture toughness
KW - Oxide glass
KW - Mechanical properties
KW - Alkali-aluminosilicate glasses
KW - Internal friction
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651540
DO - https://doi.org/10.1016/j.mtadv.2025.100669
SN - 2590-0498
VL - 29
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-65154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moschetti, Michael
A1 - Lemiasheuski, Anton
A1 - Bajer, Evgenia
A1 - Porohovoj, Ilja
A1 - Göbel, Artur
A1 - Pfennig, Anja
A1 - Bettge, Dirk
A1 - Maaß, Robert
T1 - Robot-Assisted Automated Serial-Sectioning and Imaging for 3D Microstructural Investigations
N2 - Comprehensive materials characterization requires precise structural knowledge beyond traditional methods. The robot-assisted automated serial-sectioning and imaging (RASI) platform, developed at BAM, provides automated 3D metallographic reconstructions, enabling detailed microstructural analysis of technical materials. This article showcases RASI’s capabilities through several case studies, including characterization of lamellar graphite in gray cast iron, porosity in sintered steel, melt pool morphology in additively manufactured 316L stainless steel, defects in metal-ceramic packages, and oxidation behavior in an Fe-12Cr-2Co alloy. By automating sample handling, mechanical serial-sectioning, etching, and optical imaging, RASI captures complex 3D microstructures with high precision and at high speed. This approach reveals microstructural features missed by 2D analysis, even using stereological assumptions. Specifically, statistically rare and large microstructural features, such as secondary phases or interconnected pores, become apparent, which 2D methods cannot reveal. The generated volumetric data can furthermore serve as quantitative reference datasets (i.e., the ‘ground truth’) essential for validating other 3D characterization techniques and computational models, helping to bridge the gap between predictive simulations and real-world material behavior. RASI’s modular design makes it a flexible tool that provides realistic 3D insights into materials, which can be used for advanced materials research, process optimization, and quality control.
KW - 3D metallography
KW - Automated microstructure characterization
KW - Image segmentation
KW - Mechanical polishing based serial-sectioning
KW - Process-microstructure-property relationships
KW - Quantitative microstructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649614
DO - https://doi.org/10.1002/adem.202502202
SN - 1527-2648
VL - 28
IS - 2
SP - 1
EP - 14
PB - Wiley-VCH GmbH
AN - OPUS4-64961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tehranchi, Ali
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
T1 - Hydrogen enhanced dislocation cross-slip in polycrystalline nickel
N2 - Hydrogen embrittlement (HE), degradation of the mechanical properties of metals due to the presence of hydrogen, is a persistent problem that has been attracting the attention of the material science community for about fifteen decades. Extensive experimental observations indicate the presence of nanovoids and the increase of free volume at the grain boundaries in hydrogen contaminated metals. This rate-dependent phenomenon motivates theoretical investigations of the underlying mechanisms. Here, a hydrogen enhanced cross-slip (HECS) mechanism in the close vicinity of the grain boundaries is demonstrated by direct molecular dynamics simulations and theoretical calculations. To this end, the interaction of screw dislocations with a variety of symmetric tilt grain boundaries in H-charged and H-free bicrystalline nickel is examined. The presence of segregated H atoms at the grain boundaries induces a stress field in their vicinity, and thus,- the barrier for cross-slip of screw dislocations considerably decreases. The enhanced cross-slip of dislocations facilitates the formation of jogs on bowedout dislocations. These jogs can form vacancies during the glide process. This mechanism of defect production shows nanoscale evidence of enhanced vacancy formation and subsequent increase in the free volume along the grain boundaries in the presence of H.
KW - Hydrogen embrittlement
KW - Dislocation
KW - Grain boundary
KW - Void formation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649858
DO - https://doi.org/10.1103/7l8f-3fbm
SN - 2475-9953
VL - 9
IS - 12
SP - 1
EP - 16
PB - American Physical Society (APS)
AN - OPUS4-64985
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Wallis, Theophilus
A1 - Maaß, Robert
A1 - Darvishi Kamachali, Reza
T1 - Thermodynamics of grain boundary segregation transition and their relevance for liquid metal embrittlement in Fe-Zn system
N2 - Grain boundaries (GBs) are common sites of failure in polycrystalline materials. Recently, a massive Zn segregation transition at Fe GBs was discovered and shown to act as a potent precursor of liquid metal embrittlement (LME) in the Fe-Zn system (Kamachali et al., Scripta Materialia 238 (2024) 115758). In this study, we elaborate on how temperature, GB type and the chemo-structurally coupled phase decomposition at the GB impact this segregation transition. CALPHAD and atomistic simulation data were utilized as inputs to conduct quantitative density-based thermodynamic modeling and phase-field simulations across various GBs, alloy compositions, and temperatures. We reveal that once the segregation transition becomes possible, the GB structural variation stabilizes spinodally formed Zn-rich phases within the GB region, with a higher tendency in disordered GBs. GB phase diagrams were constructed to identify and analyze the range of critical temperatures and alloy compositions associated with the segregation transition. The phase diagrams reveal that the miscibility gap for more disordered GB expands and, although the segregation transition is inevitable and occurs for all GBs, the barrier to triggering it is lower for more disordered GBs. Based on our thermodynamic analyses, potential processing modifications and GB engineering strategies for mitigating segregation-induced LME are thoroughly discussed.
KW - Thermodynamics
KW - Phase-Field Modelling
KW - Steels
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634145
DO - https://doi.org/10.1016/j.actamat.2025.121134
SN - 1359-6454
VL - 296
SP - 1
EP - 11
PB - Elsevier BV
AN - OPUS4-63414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qu, R.
A1 - Maaß, Robert
A1 - Liu, Z.
A1 - Tönnies, D.
A1 - Tian, L.
A1 - Ritchie, R.
A1 - Zhang, Z.
A1 - Volkert, A.
T1 - Flaw-insentive fracture of a micrometer-sized brittle metallic glass
N2 - Brittle materials, such as oxide glasses, are usually very sensitive to flaws, giving rise to a macroscopic fracture strength that is much lower than that predicted by theory. The same applies to metallic glasses (MGs), with the important difference that these glasses can exhibit certain plastic strain prior to catas- trophic failure. Here we consider the strongest metallic alloy known, a ternary Co 55 Ta 10 B 35 MG. We show that this macroscopically brittle glass is flaw-insensitive at the micrometer scale. This discovery emerges when testing pre-cracked specimens with self-similar geometries, where the fracture stress does not de- crease with increasing pre-crack size. The fracture toughness of this ultra-strong glassy alloy is further shown to increase with increasing sample size. Both these findings deviate from our classical under- standing of fracture mechanics, and are attributed to a transition from toughness-controlled to strength- controlled fracture below a critical sample size.
KW - Metallic glass
KW - Fracture toughness
KW - Size effect
KW - Small-scale
PY - 2021
DO - https://doi.org/10.1016/j.actamat.2021.117219
VL - 218
PB - Elsevier Ltd.
AN - OPUS4-53097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Structural dynamics in metallic glasses due to Thermal and Mechanical Stress
N2 - This talk addresses aging induced property changes of metallic glasses. Priority is given thermally and mechanically induced structural changes, of which the time-dependent dynamics is tracked using coherent scattering. Strong intermittency is observed and accelerated transport is seen at the smallest applied stresses. These findings have significant implications for how metallic glass components respond in realistic service conditions.
T2 - Seminar Universität Münster 2020
CY - Münster, Germany
DA - 01.12.2020
KW - Metallic glasses
KW - Structure
PY - 2020
AN - OPUS4-60714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, C.
A1 - Ikeda, Yuki
A1 - Maaß, Robert
T1 - Strain-dependent shear-band structure in a Zr-based bulk metallic glass
N2 - This work presents strong evidence for structural damage accumulation as a function of shear strain admitted by shear bands in a Zr-based bulk metallic glass. Analyzing the shear-band structure of shear- band segments that experienced shear strains covering four orders of magnitude with high-angle annular dark field transmission electron microscopy (HAADF-STEM) reveals strongly scattered data with on overall trend of increasing local volume dilatation with increasing shear strain. Locally, however, a variety of trends is observed, which underlines the strong heterogeneity of structural damage in shear bands in metallic glasses.
KW - Transmission electron microscopy
KW - Metallic glass
KW - Shear bands
KW - Shear-band structure
KW - Shear strain
PY - 2021
DO - https://doi.org/10.1016/j.scriptamat.2020.08.030
VL - 190
SP - 75
EP - 79
PB - Elsevier Ltd.
AN - OPUS4-52454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Esakkiraja, N.
A1 - Vishwakarma, A.
A1 - Makineni, S. K.
A1 - Jayaram, V.
A1 - Hickel, Tilmann
A1 - Divinski, S. V.
A1 - Paul, A.
T1 - Diffusion-controlled growth and microstructural evolution between Pt and Pd containing B2-NiAl bondcoats and Ni-based single crystal superalloy
N2 - Pt-modified NiAl bond coats are used to extend the lifetime of blades in gas turbine engine applications. However, they suffer from the growth of deleterious precipitates within the interdiffusion zone. Partial substitution of Pt by Pd is advantageous in reducing the interdiffusion zone thickness between the bond coat and the superalloy, providing comparable oxidation properties, and critically reducing the propensity to form brittle (Pt,Ni)Al2 precipitates. In this study, we utilize the pseudo-binary diffusion couple method to estimate the interdiffusion coefficients of Ni and Al in Pd, Pd-Pt and Pt-modified nickel aluminides. Additionally, the main and cross-interdiffusion coefficients are estimated in the ternary diffusion couples. The estimated diffusion coefficients in the 𝛽-NiAl phase reflect on the thickness of the 𝛽 phase in the superalloy bond coat interdiffusion zone. Pd reduces the pseudo-binary interdiffusion coefficients of Ni–Al and also decreases the main and cross-ternary interdiffusion coefficients. This correlates with the reduction of the interdiffusion zone thickness by Pd. The diffusion process is strongly assisted by point defects in this phase. Ab initio-informed defect calculations are done to explain diffusion retardation in the presence of Pd (compared to Pt) with decreased defect concentrations. Furthermore, through in-depth microstructure characterization performed by electron probe micro analyser, transmission electron microscopy, and atom probe tomography, the presence of 𝜎, 𝑅 and 𝜇 phases as TCP precipitates in the interdiffusion zone are identified. The results give insights into the coatings’ diffusional properties that influence the service life of the product.
KW - Interdiffusion
KW - Bondcoat
KW - Topologically close pack (TCP) phase
KW - Transmission electron microscopy
KW - Atom probe tomography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618091
DO - https://doi.org/10.1016/j.actamat.2024.119687
SN - 1359-6454
VL - 266
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61809
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhu, L.
A1 - Srinivasan, P.
A1 - Gong, Y.
A1 - Hickel, Tilmann
A1 - Grabowski, B.
A1 - Körmann, Fritz
A1 - Neugebauer, J.
T1 - Melting properties of the refractory metals V and W and the binary VW alloy fully from first principles
N2 - We investigate the melting properties of the bcc refractory metals V and W, and the disordered equiatomic VW alloy from first principles. We show that thermal vibrations have a large impact on the electronic density of states (DOS) and thus considerably affect the electronic contribution to the free energy. For W, the impact of vibrations on the electronic free energy of solid and liquid is different. This difference substantially impacts the computed melting point and also triggers a large electronic heat capacity difference between solid and liquid. For V, although vibrations likewise affect the electronic free energy, the effect on the melting properties cancels out to a large degree. For the binary VW alloy we observe a similar impact as for W, but slightly weaker. The underlying physics is explained in terms of the electronic DOS of the solid and liquid phases. Based on our accurate first-principles results, we reveal critical limitations of the Sommerfeld approximation in predicting the electronic heat
KW - Crystal melting
KW - Thermodynamics
KW - Metals
KW - Ab initio molecular dynamics
KW - Density functional theory
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618100
DO - https://doi.org/10.1103/PhysRevB.109.094110
SN - 2469-9950
VL - 109
IS - 9
SP - 1
EP - 18
PB - American Physical Society (APS)
AN - OPUS4-61810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janssen, J.
A1 - Makarov, E.
A1 - Hickel, Tilmann
A1 - Shapeev, A.V.
A1 - Neugebauer, J.
T1 - Automated optimization and uncertainty quantification of convergence parameters in plane wave density functional theory calculations
N2 - First principles approaches have revolutionized our ability in using computers to predict, explore, and design materials. A major advantage commonly associated with these approaches is that they are fully parameter-free. However, numerically solving the underlying equations requires to choose a set of convergence parameters. With the advent of high-throughput calculations, it becomes exceedingly important to achieve a truly parameter-free approach. Utilizing uncertainty quantification (UQ) and linear decomposition we derive a numerically highly efficient representation of the statistical and systematic error in the multidimensional space of the convergence parameters for plane wave density functional theory (DFT) calculations. Based on this formalism we implement a fully automated approach that requires as input the target precision rather than convergence parameters. The performance and robustness of the approach are shown by applying it to a large set of elements crystallizing in a cubic fcc lattice.
KW - Ab initio simulations
KW - High throughput
KW - convergence parameter
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618632
DO - https://doi.org/10.1038/s41524-024-01388-2
VL - 10
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Yu
A1 - Bo, Zhen-Xing
A1 - Zhou, Hong Bo
A1 - Sun, Bao-An
A1 - Sun, Yong Hao
A1 - Maaß, Robert
A1 - Wang, Wei Hua
T1 - Nanoindentation reveals universal scaling of pop-in plasticity in metallic glasses
N2 - Plastic flow of metallic glasses proceeds intermittently in the inhomogeneous deformation regime. Mediated via shear bands, quasi-static straining gives rise to plastic instabilities that are measured as abrupt displacement bursts or pop-ins. The latter is a well-known feature in nanoindentation, where its first occurrence probes the critical and site-specific stress of nano-scale incipient shear deformation. Here we show that the statistical distribution of the stress and magnitude of the first shear instability, as well as its successive higher-order events, universally follow Weibull statistics across ten different metallic glasses. This indicates a fundamentally identical plastic process across glass-forming alloys and progressing deformation that is governed by a weakest-link phenomenon. This finding stands in strong contrast to crystalline alloys, where both defect nucleation and defect-structure evolution control shear instabilities and depend on the deformation history.
KW - Metallic glasses
KW - Nanoindentation
KW - Intermittent flow
KW - Pop-ins
KW - Weibull distribution
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624772
DO - https://doi.org/10.1016/j.scriptamat.2025.116549
VL - 259
SP - 1
EP - 5
PB - Elsevier Inc.
AN - OPUS4-62477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Mathews, P.
A1 - Berkels, B.
A1 - Delis, W.
A1 - Saood, S.
A1 - Alhassan, A.
A1 - Keuter, P.
A1 - Schneider, J.
A1 - Korte-Kerzel, S.
A1 - Sandlöbes, S.
A1 - Raabe, D.
A1 - Neugebauer, j.
A1 - Dehm, G.
A1 - Hickel, Tilmann
A1 - Scheu, C.
A1 - Zhang, S.
T1 - Materials Design by Constructing Phase Diagrams for Defects
N2 - Phase transformations and crystallographic defects are two essential tools todrive innovations in materials. Bulk materials design via tuning chemicalcompositions is systematized using phase diagrams. It is shown here that thesame thermodynamic concept can be applied to manipulate the chemistry atdefects. Grain boundaries in Mg–Ga system are chosen as a model system,because Ga segregates to the boundaries, while simultaneously improving thestrength and ductility of Mg alloys. To reveal the role of grain boundaries,correlated atomic-scale characterization and simulation to scope and buildphase diagrams for defects are presented. The discovery is enabled bytriggering phase transformations of individual grain boundaries through localalloying, and sequentially imaging the structural and chemical changes usingatomic-resolution scanning transmission electron microscopy. Ab initiosimulations determined the thermodynamic stability of grain boundaryphases, and found out that increasing Ga content enhances grain boundarycohesion, relating to improved ductility. The methodology to trigger, trace,and simulate defect transformation at atomic resolution enables a systematicdevelopment of defect phase diagrams, providing a valuable tool to utilizechemical complexity and phase transformations at defects.
KW - Automatic pattern recognition
KW - Defect phase diagram
KW - Density functional theory
KW - Grain boundary complexion
KW - Transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618063
DO - https://doi.org/10.1002/adma.202402191
SN - 1521-4095
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-61806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Das, Amlan
A1 - Rashidi, Reza
A1 - Dufresne, Eric
A1 - Maaß, Robert
T1 - Metallic glasses: Elastically stiff yet flowing at any stress
N2 - Crystalline solids have a minimum stress needed to displace atoms or to move defects. This stress defines the true elastic limit and is generally a sizeable share of the macroscopic yield stress. Here we demonstrate that a metallic glass, an amorphous solid with a yield stress in the giga-pascal regime, lacks such a true microscopic elastic limit. Leveraging in-situ coherent x-ray scattering, we uncover a strongly accelerated atomic-scale transport upon the application of a stress as small as 0.005 times the yield stress. With increasing stress levels, the distribution of structural relaxation times changes from compressed exponential to simple exponential form, revealing a stress–temperature equivalence in the time-scale domain. These findings strongly promote a microstructurally heterogeneous picture of metallic glasses, in which a part of the amorphous microstructure controls macroscopic yielding whereas another part admits microplastic flow at any stress.
KW - Metallic glasses
KW - Microstructure
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624530
DO - https://doi.org/10.1016/j.mattod.2024.11.015
VL - 82
SP - 92
EP - 98
PB - Elsevier B.V.
AN - OPUS4-62453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ji, Y.
A1 - Becker, S.
A1 - Lu, Z.
A1 - Mezhov, Alexander
A1 - von Klitzing, R.
A1 - Schmidt, Wolfram
A1 - Stephan, D.
T1 - Effect of resting time on rheological properties of glass bead suspensions - Depletion and bridging force among particles
N2 - The effect of resting time on the rheological properties of cement suspensions is generally explained by early formed structure and overconsumption of polycarboxylate superplasticizers (PCEs). In this paper, we propose that the influence of resting time on the rheological properties is closely related to size variation of non-absorbed PCE. To identify this, glass bead suspensions were prepared with various amounts of PCE and ionic solution, and their rheological properties were evaluated at various times. We found that the yield stress increases with time at higher PCE concentrations and higher ionic strength solutions. Adsorbed PCE during resting tends to bridge the particles rather than disperse them. In addition, it was found that hydrodynamic radius of PCE increased with resting time, and depletion forces resulting from non-absorbed PCE size changes correlate well with the increased yield stress.
KW - Depletion force
KW - Ionic stregth
KW - PCE
KW - Rheology
KW - Resting time
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587193
DO - https://doi.org/10.1111/jace.19469
SN - 0002-7820
SN - 1551-2916
VL - 107
IS - 1
SP - 624
EP - 639
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühler, M. M.
A1 - Hollenbach, P.
A1 - Michalski, A.
A1 - Meyer, S.
A1 - Birle, E.
A1 - Off, R.
A1 - Lang, Ch.
A1 - Schmidt, Wolfram
A1 - Cudmani, R.
A1 - Fritz, O.
A1 - Baltes, G.
A1 - Kortmann, G.
T1 - The Industrialisation of Sustainable Construction: A Transdisciplinary Approach to the Large-Scale Introduction of Compacted Mineral Mixtures (CMMs) into Building Construction
N2 - Abstract: Increasing demand for sustainable, resilient, and low-carbon construction materials has highlighted the potential of Compacted Mineral Mixtures (CMMs), which are formulated from various soil types (sand, silt, clay) and recycled mineral waste. This paper presents a comprehensive inter- and transdisciplinary research concept that aims to industrialise and scale up the adoption of CMM-based construction materials and methods, thereby accelerating the construction industry’s systemic transition towards carbon neutrality. By drawing upon the latest advances in soil mechanics, rheology, and automation, we propose the development of a robust material properties database to inform the design and application of CMM-based materials, taking into account their complex, time-dependent behaviour. Advanced soil mechanical tests would be utilised to ensure optimal performance under various loading and ageing conditions. This research has also recognised the importance of context-specific strategies for CMM adoption. We have explored the implications and limitations of implementing the proposed framework in developing countries, particularly where resources may be constrained. We aim to shed light on socio-economic and regulatory aspects that could influence the adoption of these sustainable construction methods. The proposed concept explores how the automated production of CMM-based wall elements can become a fast, competitive, emission-free, and recyclable alternative to traditional masonry and concrete construction techniques.
We advocate for the integration of open-source digital platform technologies to enhance data accessibility, processing, and knowledge acquisition; to boost confidence in CMM-based technologies; and to catalyse their widespread adoption. We believe that the transformative potential of this research necessitates a blend of basic and applied investigation using a comprehensive, holistic, and transfer-oriented methodology. Thus, this paper serves to highlight the viability and multiple benefits of CMMs in construction, emphasising their pivotal role in advancing sustainable development and resilience in the built environment.
KW - Decarbonisation
KW - Circular economy
KW - Recycled materials
KW - Demolition wastes
KW - Low-carbon construction
KW - Building with earth
KW - Compressed earth
KW - Rammed earth
KW - Sustainable construction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583260
DO - https://doi.org/10.3390/su151310677
VL - 15
IS - 13
SP - 1
EP - 25
PB - MDPI
AN - OPUS4-58326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munsch, Sarah Mandy
A1 - Schmidt, Wolfram
A1 - Lorenzoni, Renata
A1 - Telong, Melissa
A1 - Grobla, Lili
A1 - Lauinger, Robert
A1 - Kruschwitz, Sabine
T1 - Investigation of the hydration of clinker‑reduced cementitious binders by 1H NMR relaxometry
N2 - In this paper, we demonstrate the value of 1 H NMR relaxometry for studying the hydration of clinker-reduced, climate-friendly cementitious binders. Our study includes white cement (WC), ordinary Portland cement (OPC), and samples incorporating reactive agro-waste based ashes and non-reactive biochars as supplementary cementitous materials (SCM). NMR measurements were performed over a period of up to 120 h during hydration with an echo time of 50 μ s and a relatively large sample size of 20 mL. The results were compared to heat flow calorimetry (HFC) data, and a detailed comparison with literature data was performed for pure OPC and WC. The results show that time-resolved NMR measurements, especially the analysis of individual NMR signal components assigned to defined 1 H reservoirs, are effective for studying hydration processes. They offer insights into the evolution of the microstrucure and specific chemical phases. NMR provides valuable information and serves as a good complement to HFC. The comparison with data obtained with shorter echo times (40 μs or around 15–45 μs with solid echo sequence) on much smaller samples showed almost identical developments with respect to the T2 distributions. For the SCM samples, NMR results indicated partially accelerated hydration processes compared to classical OPC hydration. One SCM sample acted as a highly reactive pozzolan, showing a similar hydration process to OPC with the strongest effect observed when superplasticizer was added.
Adding biochar delayed C-S-H gel pore formation but significantly increased capillary pores and even free water, likely due to the sponge-like structure.
KW - Nuclear magnetic resonance relaxometry
KW - Heat flow calorimetry
KW - Cement
KW - Hydration
KW - Clinker reduction
KW - Carbon emission
KW - Kinetics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630284
DO - https://doi.org/10.1617/s11527-025-02632-x
SN - 1871-6873
VL - 58
IS - 137
SP - 1
EP - 23
PB - Springer Nature
AN - OPUS4-63028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mendive Tapia, Eduardo
A1 - Patrick, Christopher E
A1 - Hickel, Tilmann
A1 - Neugebauer, Jörg
A1 - Staunton, Julie B
T1 - Quantification of electronic and magnetoelastic mechanisms of first-order magnetic phase transitions from first principles: application to caloric effects in La(FexSi1-x)(13)
N2 - La(FexSi1−x)13 and derived quaternary compounds are well-known for their giant, tunable, magneto- and barocaloric responses around a first-order paramagnetic-ferromagnetic transition near room temperature with low hysteresis. Remarkably, such a transition shows a large spontaneous volume change together with itinerant electron metamagnetic features. While magnetovolume effects are well-established mechanisms driving first-order transitions, purely electronic sources have a long, subtle history and remain poorly understood. Here we apply a disordered local moment picture to quantify electronic and magnetoelastic effects at finite temperature in La(FexSi1−x)13 from first-principles. We obtain results in very good agreement with experiment and demonstrate that the magnetoelastic coupling, rather than purely electronic mechanisms, drives the first-order character and causes at the same time a huge electronic entropy
contribution to the caloric response.
KW - Caloric effects
KW - Ab initio thermodynamics
KW - Magnetoeleastic couplin
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587882
DO - https://doi.org/10.1088/2515-7655/acd027
SN - 2515-7655
VL - 5
IS - 3
SP - 1
EP - 16
PB - IOP Publishing
AN - OPUS4-58788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Das, Amlan
A1 - Dufresne, Eric
A1 - Derlet, Peter M.
A1 - Maaß, Robert
T1 - Intermittent cluster dynamics and temporal fractional diffusion in a bulk metallic glass
N2 - Glassy solids evolve towards lower-energy structural states by physical aging. This can be characterized by structural relaxation times, the assessment of which is essential for understanding the glass’ time-dependent property changes. Conducted over short times, a continuous increase of relaxation times with time is seen, suggesting a time-dependent dissipative transport mechanism. By focusing on micro-structural rearrangements at the atomic-scale, we demonstrate the emergence of sub-diffusive anomalous transport and therefore temporal fractional diffusion in a metallic glass, which we track via coherent x-ray scattering conducted over more than 300,000 s. At the longest probed decorrelation times, a transition from classical stretched exponential to a power-law behavior occurs, which in concert with atomistic simulations reveals collective and intermittent atomic motion. Our observations give a physical basis for classical stretched exponential relaxation behavior, uncover a new power-law governed collective transport regime for metallic glasses at long and practically relevant time-scales, and demonstrate a rich and highly non-monotonous aging response in a glassy solid, thereby challenging the common framework of homogeneous aging and atomic scale diffusion.
KW - Glassy solids
KW - Fractional diffusion
KW - Coherent x-ray scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608015
DO - https://doi.org/10.1038/s41467-024-50758-3
VL - 15
IS - 1
SP - 1
EP - 9
PB - Springer Science and Business Media LLC
AN - OPUS4-60801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Zengquan
A1 - Riechers, Birte
A1 - Derlet, Peter M.
A1 - Maaß, Robert
T1 - Atomic cluster dynamics causes intermittent aging of metallic glasses
N2 - In the past two decades, numerous relaxation or physical aging experiments of metallic glasses have revealed signatures of intermittent atomic-scale processes. Revealed via intensity cross-correlations from coherent scattering using X-ray photon correlation spectroscopy (XPCS), the observed abrupt changes in the time-domain of atomic motion does not fit the picture of gradual slowing down of relaxation times and their origin continues to remain unclear. Using a binary Lennard-Jones model glass subjected to microsecond-long isotherms, we show here that temporally and spatially heterogeneous atomic-cluster activity at different length-scales drive the emergence of highly non-monotonous intensity cross-correlations. The simulated XPCS experiments reveal a variety of time-dependent intensity-cross correlations that, depending on both the structural evolution and the 𝑞-space sampling, give detailed insights into the possible structural origins of intermittent aging measured with XPCS.
KW - Metallic glasses
KW - Aging
KW - Molecular dynamics
KW - XPCS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595415
DO - https://doi.org/10.1016/j.actamat.2024.119730
SN - 1359-6454
VL - 267
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-59541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Manzoni, Anna Maria
A1 - Springer, H.
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - Local lattice distortions and chemical short-range order in MoNbTaW
N2 - Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, δexp, is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO.
KW - High Entropy Alloys
KW - Short-range order
KW - Lattice distortions
KW - EXAFS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598164
DO - https://doi.org/10.1080/21663831.2024.2326014
SN - 2166-3831
VL - 12
IS - 5
SP - 346
EP - 354
PB - Taylor & Francis
AN - OPUS4-59816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tehranchi, Ali
A1 - Chakraborty, Poulami
A1 - López Freixes, Martí
A1 - McEniry, Eunan J.
A1 - Gault, Baptiste
A1 - Hickel, Tilmann
A1 - Neugebauer, Jörg
T1 - Tailoring negative pressure by crystal defects: Microcrack induced hydride formation in Al alloys
N2 - Climate change motivates the search for non-carbon-emitting energy generation and storage solutions. Metal hydrides show promising characteristics for this purpose. They can be further stabilized by tailoring the negative pressure of microstructural and structural defects. Using systematic ab initio and atomistic simulations, we demonstrate that an enhancement in the formation of hydrides at the negatively pressurized tip region of the microcrack is feasible by increasing the mechanical tensile load on the specimen. The theoretical predictions have been used to reassess and interpret atom probe tomography experiments for a high-strength 7XXX-aluminium alloy that show a substantial enhancement of hydrogen concentration at structural defects near a stress-corrosion crack tip. These results contain important implications for enhancing the capability of metals as H-storage materials.
KW - Physics and Astronomy (miscellaneous)
KW - Hydrogen storage
KW - Ab initio Simulation
KW - Microcracks
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587878
DO - https://doi.org/10.1103/PhysRevMaterials.7.105401
SN - 2475-9953
VL - 7
IS - 10
SP - 105401-1
EP - 105401-12
PB - American Physical Society (APS)
AN - OPUS4-58787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Aristia, Gabriela
T1 - Polyaniline/Silicon Dioxide Composite-Based Coating for Corrosion Protection in Geothermal Systems
N2 - Geothermal energy is one of the cleanest renewable alternatives to reduce the dependency on fossil fuel [1, 2]. Despite its promising future, its implementation faces various challenges, one of them being corrosion processes. To implement this energy, hot fluids are pumped from a geothermal well. These hot fluids originate from deep within the earth, so consist of different ionic species and gases in a wide range of temperatures, which lead to their corrosive nature. In terms of geothermal energy resources, Indonesia is at the forefront, with the highest preserved geothermal energy in the world of about 29 GWe and 312 potential geothermal locations [3]. Geothermal wells in Sibayak (North Sumatera), Indonesia, belong to young stratovolcanoes and have operating temperatures varying from 36 °C at the near ground surface to 310 °C at the bottom of the well, which is liquid-dominated with acidic and saline properties [4, 5]. Therefore, this geothermal fluid creates an aggressive environment that is conducive to corrosion of the powerplant infrastructure.
Parts of the geothermal powerplant infrastructure, such as pipelines and heat exchangers, are commonly made of metals, e.g. carbon steel and stainless steel. Consequently, they may undergo corrosion and scaling when exposed to the geothermal fluid, especially for carbon steel. To ensure the safety and longevity of a geothermal powerplant, the infrastructure is constructed of expensive corrosion resistant alloys [6–10], e.g., titanium and Ni-Cr based alloys, or carbon steel which needs to be protected by coatings or inhibitors.
To address the corrosion of carbon steel in the geothermal environment, artificial geothermal water was used to simulate a geothermal well in Sibayak, Indonesia, with pH 4 and a saline composition of 1,500 mg/l Cl-, 20 mg/l SO42-, 15 mg/l HCO3-, 200 mg/l Ca2+, 250 mg/l K+, and 600 mg/l Na+. Carbon steel underwent the most severe corrosion at 150°C in an oxygen-containing solution with a corrosion rate of 0.34 mm/year, which is approximately ten times higher than that in the absence of dissolved oxygen. In all conditions, pitting corrosion was observed, which necessitate a protection strategy on carbon steel. In order to promote a cost effective and locally available option, this work focused on an easily applicable coating which utilized local resources.
Toward developing such protective coating based on the locally available resources in Indonesia which can yield good corrosion resistance and thermal stability in geothermal environment, two additional components, i.e. polyaniline (PANI) and silicon dioxide, were used to modify an alkyd-based commercial coating. The selection of the alkyd-based coating as a matrix focused on the industrial convenience basis, where the coating application procedure should be simple and easy to apply within reasonable costs. The alkyd-based coating underwent severe blistering when exposed to the artificial geothermal water at 70 and 150°C due to the reaction between CaCO3 (as one of its components) and the artificial geothermal water, as well as a possible alkyd hydrolysis in the initial stage of exposure. In the oxygen-free solution, the degradation was controlled by chemical and thermal reactions, whereas in the aerated condition, oxidization at the coating surface further accelerated polymer degradation.
PANI was chosen as one of the anticorrosion pigments which was widely developed over the past decades. To investigate the interaction between PANI and the artificial geothermal water, PANI film was electrochemically deposited on the carbon steel surface and exposed to the artificial geothermal water. Electrochemically synthesized oxalate-doped PANI was protective against corrosion of carbon steel in artificial geothermal water at room temperature. The mechanism involved an exchange of electroactive species within the coating layer, as confirmed by electrochemical impedance spectra. Interaction of ionic species, such as Cl-, Na+, Ca2+ from the artificial geothermal water, with the outer layer of PANI is suggested both at 25°C and 150°C, based on the EDX spectra of the coating surface after exposure to the artificial geothermal water. Thus, the protection mechanism of PANI is not solely based on the physical barrier layer properties, but rather associated with the redox mediated properties of PANI, which selectively allow ionic species intrusion from the electrolyte into the PANI layer. Although PANI is a promising candidate as an anticorrosion coating, its morphological characterization reveals that electrochemically deposited PANI is not stable for an application at 150°C. Therefore, another approach was used to promote better protective behavior of PANI by dispersing chemically synthesized PANI in the alkyd-based coating.
To enhance the thermal stability of the coating, silicon dioxide (SiO2) was added, which was able to prolong the sustainability of coated metals until 28 days compared to the unmodified alkyd-based coating, which underwent a change in color to brown/orange only within 7 days of exposure. This improvement might be associated with the role of SiO2 to proportionate the thermal expansion coefficient of the coating system to be compatible with that of carbon steel. Although the coating is thermally enhanced, the electrolyte might still intrude through the coating resulting in the change of coating color after 28 days of exposure in the artificial geothermal water. When PANI was added, the coating system provided an active corrosion protection on the carbon steel surface. The chemical and morphological characterization of the PANI-alkyd and SiO2-alkyd coating system showed that coatings were improved, and no blisters were observed, albeit the degradation continued. Based on the results of exposure tests, the combined coating system was further investigated.
The combinational coating of PANI/SiO2-alkyd was used with 2 wt% of PANI and 15 wt% of SiO2. Electrochemical tests indicated cathodic protection at 150°C, as the Ecorr of PANI/SiO2 remained approximately 400 mV lower than the carbon steel potential. The impedance spectra of the combinational coating of PANI/SiO2 showed a continuous decrease in the absolute impedance value over time. A significant decrease was observed within one day of exposure, followed by a slow gradual decrease, which might be associated with water absorption in the coating. FTIR spectra revealed that several peaks associated with the organic portion of the coatings were reduced after the specimens were exposed for 6 months. However, the absorption peaks related to the inorganic portion of the coatings remained stable until 6 months. Morphological characterization of the combinational coating of PANI/SiO2 showed that there were no blisters or significant discoloration of coatings after long-term exposure for 6 months in artificial geothermal water at 150°C, indicating that the chemical degradation does not significantly affect the functionality of the coating. This clearly shows the durability of PANI/SiO2 coating in the geothermal condition, suggesting that this coating can be used for such geothermal application. However, further testing of this coating should be conducted in a real geothermal environment on-site to ensure safety and viability.
KW - Geothermal
KW - Corrosion
KW - Coating
KW - Polyaniline
KW - Electrochemical impedance spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:188-refubium-26704-6
UR - https://refubium.fu-berlin.de/handle/fub188/26704
DO - https://doi.org/10.17169/refubium-26461
SP - 1
EP - 175
CY - Berlin
AN - OPUS4-51281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, M.
A1 - Schubert, Nils
A1 - Günster, Jens
A1 - Stawarczyk, B.
A1 - Zocca, Andrea
T1 - Additive manufacturing of glass-ceramic dental restorations by layerwise slurry deposition (LSD-print)
N2 - This study is dedicated to the additive manufacturing of a feldspar glass-ceramic for dental applications by LSD-print (layerwise slurry deposition) technology, a variation of binder jetting using water-based ceramic slurries as feedstock. This technology was investigated for the manufacturing of single tooth restoration demonstrators with good aesthetic properties, and to compare the additively manufactured material with a commercial reference. Model restorations with > 99 % relative density were processed with a debinding and firing cycle of 45 min, however the whole process chain accounts for up to 30 hours. Significant differences between LSD-printed and reference materials were found for fracture strength, fracture toughness and Martens parameters. Printing orientation affected shrinkage and fracture strength, but not fracture toughness and Martens parameters. Nevertheless, the results suggest that the LSD-print technology processing the developed slurry is a promising option for manufacturing dental restorations meeting class 1a requirements according to DIN EN ISO 6871:2019–01.
KW - Additive Manufacturing
KW - 3D-printing
KW - LSD-print
KW - Dental ceramics
KW - Glass-ceramic
KW - Debinding
KW - Firing
KW - Sinter-crystallization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624768
DO - https://doi.org/10.1016/j.jeurceramsoc.2025.117235
VL - 45
IS - 7
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-62476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karl, D.
A1 - Duminy, T.
A1 - Lima, P.
A1 - Kamutzki, F.
A1 - Gili, A.
A1 - Zocca, Andrea
A1 - Günster, Jens
A1 - Gurlo, A.
T1 - Clay in situ resource utilization with Mars global simulant slurries for additive manufacturing and traditional shaping of unfired green bodies
N2 - The wet processing of regolith simulant for clay in situ resource utilization (ISRU) on Mars is presented. The two raw materials from the Mars global simulant family, one without clay (MGS-1) and one with clay - sodium montmorillonite smectite - (MGS-1C) were milled and mixed to produce a simulant with small particle size and reduced clay content (MGS-1C/8). All three simulants and the pure clay raw material were extensively characterized using XRF, synchrotron XRD, gas adsorption and gas pycnometry methods. In a straightforward processing approach, MGS-1C/8 was mixed with water and different dispersant approaches were investigated, all of which gave stable slurries. Particle size distribution, rheology, ion concentration, pH and electrical conductivity of these slurries were characterized. The slurry systems can easily be adapted to fit all typical ceramic shaping routes and here parts of varying complexity from slip casting, throwing on a potter's wheel and additive manufacturing, including material extrusion (robocasting) and binder jetting (powder bed 3D printing) were produced.
The unique properties of the sodium montmorillonite clay, which is readily accessible in conjunction with magnesium sulfate on the Martian surface, acted as a natural nanosized binder and produced high strength green bodies (unfired ceramic body) with compressive strength from 3.3 to 7.5 MPa. The most elaborate additive manufacturing technique layerwise slurry deposition (LSD) produced water-resistant green bodies with a compressive strength of 30.8 ± 2.5 MPa by employing a polymeric binder, which is similar or higher than the strength of standard concrete. The unfired green bodies show sufficient strength to be used for remote Habitat building on Mars using additive manufacturing without humans being present.
KW - Mars
KW - Smectite
KW - Clay ISRU
KW - MGS-1 regolith simulant
KW - 3D printing
KW - Additive manufacturing
PY - 2020
DO - https://doi.org/10.1016/j.actaastro.2020.04.064
VL - 174
SP - 241
EP - 253
PB - Elsevier Ltd.
AN - OPUS4-50870
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Günster, Jens
T1 - Research and carrier in governmental research institute in Japan and Germany
N2 - Being invited to Japan in 1996 as a Humboldt/STA was on of the most exciting things in my life. Not that it is on an absolute scale the most exciting thing still, but at that time, just after finalizing my PhD and thinking what is coming next, it was.
KW - Networking
PY - 2022
DO - https://doi.org/10.11470/oubutsu.91.2_115
SN - 0369-8009
VL - 91
IS - 2
SP - 115
EP - 117
PB - Gakkai
CY - Tōkyō
AN - OPUS4-54462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - DELTA - Investigation of corrosion and microbially influenced corrosion processes by means of X-Ray absorption spectroscopy
N2 - Alloys relevant for corrosion research are inherently complex in chemical composition and microstructure. Their local surface chemistry differs significantly from the bulk composition and their surfaces are subjected to ever changing environmental conditions. Thus, a thorough understanding of the mechanisms leading to material degradation and failure requires a detailed characterisation of the initial and final states as well as an adequate monitoring of the relevant properties as a function of time. Moreover, corrosion products tend to oxidize in contact with the atmosphere. Microbially influenced corrosion (MIC) poses a particular challenge regarding the experimental methods that can be used for the investigations. The use of highly sensitive methods of ultra-high vacuum surface analysis requires the removal of the biofilm, which leads to significant changes in the interfacial chemistry.
In recent projects we applied X-ray absorption near edge spectroscopy (XANES) to investigate mechanisms of aqueous corrosion, high temperature corrosion and MIC processes of stainless steel and multi-principal element alloys (MPEAs). By combining in situ XANES studies on model thin films with ex situ XANES analysis of technical samples we aimed to obtain a holistic understanding of degradation processes.
In this presentation we will summarize our results on the application of XANES to corrosion and MIC research with two case studies. In the first case study, in situ and ex situ XANES were used for the investigation of aqueous and high-temperature corrosion processes of alloys from FeNiCr-Mn MPEA family to clarify the role of Mn in determining the corrosion resistance and passive film formation. Our results indicate that Mn plays a major role in suppressing Fe oxidation. In the second example we have shown by means of in situ and ex situ XANES analysis that cultivation of metal reducing bacteria (MRB) in abundance of Fe(III) ions leads to a significant increase in electrochemical activity and thus, to an accelerated corrosion of the metallic substrate. This implies that bacterial colonies released from active corrosion sites might show a preconditioning effect and pose a higher corrosion risk.
T2 - eMRS 2024 Spring Meeting
CY - Strasbourg, France
DA - 27.05.2024
KW - Corrosion
KW - XANES
KW - MIC
KW - Multi-principal element alloys
PY - 2024
AN - OPUS4-62636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Almalla, A.
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - In Situ Atomic Force Microscopy Analysis of the Corrosion Processes at the Buried Interface of an Epoxy-like Model Organic Film and AA2024-T3 Aluminum Alloy
N2 - The application of characterization methods with high spatial resolution to the analysis of buried coating/metal interfaces requires the design and use of model systems. Herein, an epoxy-like thin film is used as a model coating resembling the epoxy-based coatings and adhesives widely used in technical applications. Spin coating is used for the deposition of a 30 nm-thin bilayer (BL) composed of poly-(ethylenimine) (PEI) and poly[(o-cresyl glycidyl ether)-co-formaldehyde] (CNER). Fourier-transform infrared spectroscopy (FTIR) results confirm that the exposure of coated AA2024-T3 (AA) samples to the corrosive electrolyte solution does not cause the degradation of the polymer layer. In situ atomic force microscopy (AFM) studies are performed to monitor local corrosion processes at the buried interface of the epoxy-like film and the AA2024-T3 aluminum alloy surface in an aqueous electrolyte solution. Hydrogen evolution due to the reduction of water as the cathodic corrosion reaction leads to local blister formation. Based on the results of the complementary energy-dispersive X-ray spectroscopy (EDX) analysis performed at the same region of interest, most of the hydrogen evolved originates at the vicinity of Mg-containing intermetallic particles.
KW - Scanning Kelvin probe force microscopy
KW - Aluminum alloys
KW - Buried interfaces
KW - In situ atomic force microscopy
KW - Local corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546932
DO - https://doi.org/10.1002/adem.202101342
SN - 1438-1656
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-54693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Study of Polyaniline/Silicon Dioxide based Coating on Carbon Steel in Artificial Geothermal Brine
N2 - By using the available resources in Indonesia, such as silicon dioxide and marine coating base, the PANI/SiO2 modified alkyd coating was able to protect carbon steel in a deaerated artificial geothermal water. The screening of coatings shows that the modification by adding individual pigment was not sufficient to protect carbon steel even during a short-term exposure, indicated by the discoloration after only seven days of exposure. Electrochemical tests indicated that there was no significant change in the Ecorr between the coated and uncoated carbon steel at room temperature. At 150 °C, the coated carbon steel has a lower potential than that of carbon steel, indicating that the coating is protecting carbon steel cathodically or slowing down the corrosion reaction. Finally, a long-term exposure test confirmed that the PANI/SiO2 modified coating successfully protects the carbon steel in the Sibayak artificial geothermal water up to 150 °C for 6 months.
T2 - World Geothermal Congress
CY - Online meeting
DA - 15.06.2021
KW - Coatings
KW - Corrosion
KW - Polyaniline
KW - Sibayak
KW - SiO2
KW - Geothermal
PY - 2021
AN - OPUS4-52831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - von der Au, Marcus
A1 - Dietrich, P. M.
A1 - Radnik, Jörg
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - The comparison of the corrosion behavior of the CrCoNi medium entropy alloy and CrMnFeCoNi high entropy alloy
N2 - This work presents the determination of the corrosion characteristics of CrCoNi (medium entropy alloy) and CrMnFeCoNi (high entropy alloy) in 0.1 M NaCl and 0.1 M H2SO4. The morphology and chemical composition of the oxide layers formed on CrCoNi and CrMnFeCoNi were comparatively analyzed by scanning Kelvin probe microscopy (SKPFM) and scanning electron microscopy (SEM) and supported with chemical analysis by means of inductively coupled plasma mass spectrometry (ICP-MS) and X-Ray photoelectron spectroscopy (XPS). The analysis of the 3p core level peaks showed that the oxide layer (native and after anodic passivation) on CrCoNi consisted mainly of Cr oxides, while the oxide layer on CrMnFeCoNi was primarily composed of a mixture of Cr and Fe oxides. In addition, XPS was utilized to assess the oxide layer thicknesses. These results were compared to the thicknesses obtained by means of electrochemical impedance spectroscopy (EIS), with both approaches yielding values up to about 4 nm depending on the electrolyte and the alloy. Cyclic polarization measurements indicated superior corrosion resistance of CrCoNi in both aqueous environments compared to CrMnFeCoNi, as well as to AISI 304 stainless steel.
KW - Medium entropy alloy
KW - High entropy alloy
KW - SKPFM
KW - XPS
KW - Passivation
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559902
DO - https://doi.org/10.1016/j.apsusc.2022.154171
SN - 0169-4332
VL - 601
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-55990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - Continuous layer deposition for the Additive Manufacturing of ceramics by Layerwise Slurry Deposition (LSD-print)
N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders.
In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method enabling the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder. Not only very fine, submicron powders can be processed with low organics, but also the dense powder bed provides excellent support to the parts built. The LSD technology can be combined with binder jetting to develop the so-called “LSD-print” process. LSD-print combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to traditional processing.
The latest development of this technology shows that it is possible to print ceramic parts in a continuous process by depositing a layer onto a rotating platform, growing a powder bed following a spiral motion. The unique mechanical stability of the layers in LSD-print allows to grow a powder bed several centimeters thick without any lateral support. The continuous layer deposition allows to achieve a productivity more than 10X higher compared to the linear deposition, approaching a build volume of 1 liter/hour.
T2 - 3rd Global Conference and Exhibition on Smart Additive Manufacturing, Design & Evaluation Smart MADE
CY - Osaka, Japan
DA - 10.04.2024
KW - Additive Manufacturing
KW - Ceramic
KW - Layerwise slurry deposition
KW - LSD-print
KW - Slurry
KW - Binder jetting
PY - 2024
AN - OPUS4-60055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
A1 - Sänger, Johanna
A1 - Pauw, Brian Richard
T1 - Two-Photon-Polymerization for Ceramics Powder Processing
N2 - Manipulating ceramic powder compacts and ceramic suspensions (slurries) within their volume with light requires a minimum transparency of the materials. Compared to polymers and metals, ceramic materials are unique as they offer a wide electronic band gap and thus a wide optical window of transparency. The optical window typically ranges from below 0.3 µm up to 5µm wavelength. Hence, to penetrate with laser light into the volume of a ceramic powder compound its light scattering properties need to be investigated and tailored. In the present study we introduce the physical background and material development strategies to apply two-photon-polymerization (2PP) for the additive manufacture of filigree structures within the volume of ceramic slurries.
T2 - DKG Jahrestagung 2023
CY - Jena, Germany
DA - 27.03.2023
KW - Additive Manufacturing
KW - Transparent ceramics
PY - 2023
AN - OPUS4-59880
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meyer, Lena
T1 - 3-D Druck in Schwerelosigkeit – Patentanmeldung für den Bau für Werkzeug und Ersatzteilen im Weltall
N2 - Präsentation der Aktivitäten an der BAM im Bereich 3-D Druck in Schwerelosigkeit.
T2 - Besuch des Deutschen Patent- und Markenamtes DPMA München
CY - Berlin, Germany
DA - 19.07.2022
KW - Additive manufacturing
KW - Microgravity
KW - Patent
KW - Powder
KW - Additive Fertigung
KW - 3D Druck
KW - Schwerelosigkeit
PY - 2022
AN - OPUS4-56314
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
T1 - Continuous layer deposition for the Additive Manufacturing of ceramics by Layerwise Slurry Deposition
N2 - Powder bed technologies are among the most successful additive manufacturing (AM) techniques. The application of these techniques to most ceramics has been difficult due to the challenges associated with the deposition of homogeneous powder layers when using fine powders.
In this context, layerwise slurry deposition (LSD) has been developed as a deposition method that enables the use of powder bed AM technologies for advanced ceramic materials. In layerwise slurry deposition, a ceramic slurry is deposited in layers using a doctor blade and dried to produce a highly compacted powder. Not only can very fine submicron powders with low organic content be processed, but the dense powder bed also provides excellent support for the manufactured parts.
The latest development of this technology shows that it is possible to print ceramic parts in a continuous process by depositing a layer on a rotating platform on which a powder bed grows in a spiral motion. The unique mechanical stability of the layers in LSD printing makes it possible to build up a powder bed several centimeters thick without lateral support. Continuous layer deposition achieves more than 10 times the productivity of linear deposition, approaching a build volume of 1 liter per hour.
T2 - International Conference on Additive Manufacturing Technology Frontiers
CY - Xi’an, China
DA - 11.04.2025
KW - Ceramic
KW - advanced ceramics
PY - 2025
AN - OPUS4-63963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique authenticator for additively manufactured parts derived from their microstructure
N2 - In the field of additive manufacturing, the ability to uniquely identify and authenticate parts is crucial for certification, logistics, and anti-counterfeiting efforts. This study introduces a novel methodology that leverages the intrinsic microstructural features of additively manufactured components for their identification, authentication, and traceability. Unlike traditional tagging methods, such as embedding QR codes on the surface [1] or within the volume of parts, this approach requires no alteration to the printing process, as it utilizes naturally occurring microstructural characteristics.
The proposed workflow [2] involves the analysis of 3D micro-computed tomography data to identify specific voids that meet predefined identification criteria. This method is demonstrated on a batch of 20 parts manufactured with identical process parameters, proving capable of achieving unambiguous identification and authentication. By establishing a tamper-proof link between the physical part and its digital counterpart, this methodology effectively bridges the physical and digital realms. This not only enhances the traceability of additively manufactured parts but also provides a robust tool for integrating digital materials, parts databases, and product passports with their physical counterparts.
T2 - Artificial Intelligence in MSE
CY - Bochum, Germany
DA - 18.11.2025
KW - Authentication
KW - Additive Manufacturing
KW - Non-destructive testing
PY - 2025
AN - OPUS4-65204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bäßler, Ralph
A1 - Aristia, Gabriela
T1 - Geothermie aus dem Vulkan – sicher und wirtschaftlich
N2 - Indonesien gilt aufgrund seiner vielen Vulkane als einer der Hotspots für Geothermie. Doch Salz und Hitze setzen den Geothermie‐Anlagen zu und gefährden ihre Sicherheit und Wirtschaftlichkeit. Ein Team an der BAM hat günstigen, lokal verfügbaren Baustahl jetzt so beschichtet, dass ein nachhaltiger und sicherer Betrieb der Geothermie‐Kraftwerke möglich ist ‐ auch unter Extrembedingungen.
Das BAM‐Team will das Beschichtungssystem nun den Anwendern in Indonesien zur Verfügung stellen, damit es unter Realbedingungen in einem Geothermie‐Kraftwerk getestet werden kann. Der Schutz vor Korrosion ist mitentscheidend, weil sie die Lebensdauer dieser Kraftwerke bestimmt. Unsere Arbeit könnte die Effizienz der Energieproduktion mit Geothermie wesentlich verbessern.
KW - Geothermie
KW - Korrosion
PY - 2020
DO - https://doi.org/10.1002/maco.202070086
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 8
SP - 1
EP - 2
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51074
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baesso, Ilaria
A1 - Karl, D.
A1 - Spitzer, Andrea
A1 - Gurlo, A.
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Characterization of powder flow behavior for additive manufacturing
N2 - The flow behavior of powders has an essential role in many industrial processes, including powder bed additive manufacturing. The characterization of the flow behavior is challenging, as different methods are available, and their suitability for an application in additive manufacturing is still controversial. In this study, six standardized methods (measurement of bulk density by ISO 60 and by ASTM B329, angle of repose by ISO 4324, discharge time by ISO 6186 and by ASTM B964-16, and Hausner Ratio by ASTM 7481 – 18), the rotating drum method (by GranuDrum) and powder rheometry (Anton Paar powder cell), were applied to five size fractions of a crushed quartz sand powder and compared. A statistical approach is proposed and discussed to correlate the obtained flowability indexes with the packing density of powder beds deposited layer-by-layer, and these correlations are compared between methods. Overall, the measurement of bulk density by ASTM B329 that showed the best correlation with the powder bed density. Advanced methods such as the rotating drum method and powder rheometry did not demonstrate particularly good correlations, however they provided complementary information which can be useful to assess the dynamic behavior of powders.
KW - Powder flow
KW - Flowability
KW - Powder bed additive manufacturing
KW - Powder rheology
PY - 2021
DO - https://doi.org/10.1016/j.addma.2021.102250
SN - 2214-8604
VL - 47
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rashidi, Reza
A1 - Vaerst, Olivia
A1 - Riechers, Birte
A1 - Rösner, Harald
A1 - Wilde, Gerhard
A1 - Maaß, Robert
T1 - Atomic-scale strain fluctuations as an origin for elastic microstructures in metallic glasses
N2 - Metallic glasses (MGs) exhibit an elastic microstructure that spans from a few to hundreds of nanometers, the origin of which continues to remain poorly understood. Here we employ four-dimensional scanning transmission electron microscopy (4D-STEM) on a Zr65Cu25Al10 (at. %) bulk MG. Mapping local diffraction patterns over representative areas also probed elastically with automated nanoindentation, two comparable correlation length scales have been identified. Specifically, local diffraction patterns are analyzed with respect to their ellipticity, revealing systematic fluctuations between positive and negative volumetric strains. A power spectrum analysis of the strain fluctuations returns a dominant length scale of the order of 100 nm, which is very much compatible with what elastic property mapping indicates. Annealing reduces the magnitude of the statistical strain fluctuations, without strongly affecting the associated fluctuation length scale. These findings demonstrate that atomic-scale strains are very likely the origin of the structurally unexpected large elastic fluctuations obtained in nanoscale contact mechanics experiments.
KW - Metallic glass
KW - 4D-STEM
KW - Strain anisotropy
KW - Nanoindentation
KW - Elastic microstructure
KW - Heterogeneities
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654991
DO - https://doi.org/10.1016/j.actamat.2026.121982
SN - 1359-6454
VL - 308
SP - 1
EP - 8
PB - Elsevier Inc.
AN - OPUS4-65499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raedel, Martina
T1 - Conservation of damaged architectural aluminum elements
N2 - Aluminum is an often-used building material in modern architecture. In recent years buildings from the 1950th and 1960th are increasingly subject of conservation works including the aluminum parts. Typical surface damages are signs of corrosion caused by weathering processes or scratches in the anodized layer due to extensive wear. To repair damaged aluminum surfaces, there are usually two options: smaller areas are repaired by using a touch-up pen, for larger damages it is necessary to remove the anodized layer completely. Both possibilities are disadvantageous for the objects; the touch-up pen often does not match the color together with an insufficient corrosion protection, while newly anodized layers often differ in color and gloss from the original surface.
For this reason, a research project was initiated to develop a mobile method to repair anodized aluminum parts. The first step focusses on the mobile anodization process by using the electrolyte with a gel substrate. Different cathodic materials are to be tested together with appropriate cooling material. The anodized area should be isolated to protect undamaged areas. Examinations of the produced layers are conducted by using Keyence microscope, eddy current testing and ESEM analysis. Further steps are to transform the coloring and sealing process for mobile application. Color could be applied by using a brush or by spray while the sealing process could be performed with water vapor. An heatable putty knife could be used, if heating up the area will be necessary. Once the application process is developed, the anodization will be tested on samples with artificial damages, fixed in horizontal and vertical positions. The stability of the anodized surface will be examined by accelerated ageing in a climate chamber and outdoor weathering.
The electrolyte (diluted sulfuric acid) was combined with a gel binder to enable a mobile application. Several thickening agents were tested concerning their conductivity and stability in acid systems. Anodization tests with different cathodic material and shapes were conducted. The temperature during anodization was controlled and adjusted if necessary. The anodized area was restricted by using either a lacquer, an adhesive or a removable silicon barrier. The fist results show the feasibility of the method on enclosed areas. The achieved thickness was measured by eddy current testing and the structure was controlled by ESEM analysis. The examinations show a connection between thickness and porosity of the anodized layers and the temperature during the application process.
Next steps are testing mobile coloring and sealing methods followed by mobile anodization on artificial damaged areas.
T2 - Metal 2019
CY - Neuchâtel, Switzerland
DA - 02.09.2019
KW - Mobile anodisation
KW - Aluminium
KW - Conservation
KW - Damage repair
PY - 2020
UR - https://www.lulu.com/shop/claudia-chemello-and-laura-brambilla-and-edith-joseph/metal-2019-proceedings-of-the-interim-meeting-of-the-icom-cc-metals-working-group-september-2-6-2019-neuch%C3%A2tel-switzerland-ebook/ebook/product-24517161.html
AN - OPUS4-51479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
T1 - Electrochemical behaviors of casing steel/mortar interface in CO2 saturated aquifer fluid
N2 - To reveal the corrosion resistance of casing steel/mortar interface in CO2 injection condition, sandwich samples were prepared and exposed up to 20 weeks in aquifer fluid under 10 MPa and 60 °C. Cross section analysis revealed the crevice corrosion as main mechanism instead of pitting corrosion, which would be expected to happen in the extremely high Chloride concentration. Detailed analysis using EDS line scan shown the slow diffusion of Chloride, suggesting why pitting did not happen after 20 weeks. To mimic the passivated steel surface, the steel coupon was passivated in simulated pore solution having pH 13.5 for 42 days. The passivated coupon was further exposed to NGB solution for 28 days. Electrochemical characterization was performed along the exposure processes to reveal the change in impedance, indicating the corrosion resistance of steel casing/mortar interface.
T2 - EUROCORR 2022
CY - Berlin, Germany
DA - 28.08.2022
KW - Corrosion
KW - CO2 quality
KW - Pipeline network
KW - CCS
PY - 2022
SP - 859
EP - 865
PB - European Federation of Corrosion
AN - OPUS4-55622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Müller, Bernd R.
A1 - Laquai, René
A1 - Kupsch, Andreas
A1 - Wieder, Frank
A1 - Benemann, Sigrid
A1 - Wilbig, Janka
A1 - Günster, Jens
A1 - Bruno, Giovanni
T1 - Microstructural characterization of AP40 apatite-wollastonite glass-ceramic
N2 - The microstructure of an apatite-wollastonite (code name AP40) glass-ceramic is analyzed in this study by combining 2D microscopy, phase analysis, X-ray absorption and synchrotron X-ray refraction computed tomography (XCT and SXRCT, respectively). It is shown that this combination provides a useful toolbox to characterize the global microstructure in a wide scale range, from sub-micrometer to millimeter. The material displays a complex microstructure comprising a glassy matrix with embedded fluorapatite and wollastonite small crystals. In this matrix, large (up to 200 μm) spike-shaped structures are distributed. Such microstructural features are oriented around a central sphere, thereby forming a structure resembling a sea urchin. A unique feature of SXRCT, in contrast to XCT, is that internal interfaces are visualized; this allows one to show the 3D distribution of these urchins with exceptionally good contrast. Furthermore, it is revealed that the spike-shaped structures are not single crystals, but rather composed of sub-micrometric crystals, which are identified as fluorapatite and diopside phases by SEM-EDX analysis.
KW - Glass-ceramic
KW - X-ray refraction
KW - Computed tomography
KW - Microstructure
PY - 2023
DO - https://doi.org/10.1016/j.ceramint.2022.12.130
SN - 0272-8842
VL - 49
IS - 8
SP - 12672
EP - 12679
PB - Elsevier Science
CY - Amsterdam
AN - OPUS4-57452
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meyer, Lena
T1 - Laser beam melting additive manufacturing at μ-gravity
N2 - In-space manufacturing (ISM) provides the opportunity to manufacture and repair critical components on future human spaceflight missions. For explorations to Mars and beyond, ISM is a key strategy not only due to the long travel distances and high costs of supply from earth but also to be able to safely work in space for years. Human spaceflight is still dependent on shipments from earth that can fail for several reasons. ISM is a valuable alternative to ensure the timely and safe resupply of space missions.
With additive manufacturing (AM) technologies, components are built directly from a 3D computer-aided-design (CAD) model which offers the advantages of freedom of design and the production of complex and ready-to-use parts. A virtual tool box with 3D models in space or the supply of information instead of components from earth to space can strongly benefit future missions. For industrial use, most research has focused on laser based additive manufacturing processes such as laser beam melting (LBM) where metallic powder particles are spread into a uniform powder bed and melted by a laser to the desired shape.
In the absence of gravity, the handling of metal powders, which is essential for the process, is challenging. We present an evolution of an AM system, where a gas flow throughout the powder bed is applied to stabilize the powder bed. This is needed to compensate for the missing gravitational forces in microgravity experiments on parabolic flight campaigns. The system consists of a porous building platform acting as a filter for the fixation of metal particles in a gas flow. It is driven by reduced pressure established by a vacuum pump underneath the platform. The system creates a drag force that directs the particles towards the porous building platform, similar to the effect of the gravitational force.
The AM system with its gas-flow-assisted powder deposition has been tested in several parabolic flight campaigns, and stainless-steel powder has successfully been processed during microgravity conditions. Different powder recoating mechanisms have been investigated to assess the homogeneous distribution of the powder as well as the attachment of the next layer to the powder bed. These mechanisms included different container designs with parallel double blades and with a V-shape at the bottom, and a roller recoating system. The samples presented are the first metal parts ever manufactured using LBM in μ-gravity. In addition to manufacturing in a μ-gravity environment, the experiments have shown the feasibility to manufacture components at different accelerations during the parabolic flight: hyper gravity (1.8 g), μ-gravity (< 0.01 g) and 1 g. Recent results will also be presented describing the application of this LBM setup in a parabolic flight campaign with mixed lunar, martian and µ-gravity acceleration, during which the processing of a lunar regolith simulant powder was tested.
For ISM, the development and testing of the proposed AM system demonstrates that LBM can be considered a viable technology for the manufacturing of metal and ceramic parts in a μ-gravity or reduced-gravity environment.
T2 - International Conference on Advanced Manufacturing
CY - Online meeting
DA - 07.03.2022
KW - μ-gravity
KW - In-space manufacturing
KW - Additive manufacturing
KW - Laser beam melting
KW - Microgravity
KW - Stainless steel
KW - Lunar regolith simulant
PY - 2022
AN - OPUS4-54450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meyer, Lena
T1 - Powder based Additive Manufacturing in Space
N2 - Abstract of the event: 'The area of New Space is a vastly growing and dynamic field with a high innovative potential and many exciting ideas. After decades where activities in space were dominated and funded mainly by governmental agencies, a new industry is forming and new business models are being developed around ideas like satellite-based internet, space travel, space mining, geo-monitoring etc. For space applications, lightweight design is crucial to keep the costs at a minimum. This Innovation Day will introduce the field of New Space and present the variety of exciting opportunities that arise for composites based on their excellent lightweight potential.' Another research area is now arising in the field of 3D printing or additive manufacturing of fiber composite materials in space. At the event, we presented on the opportunities and our experiences of using a powder based additive manufacturing process for in-space manufacturing applications.
T2 - CU Innovation Day - New opportunities and applications in space with composites
CY - Online meeting
DA - 29.03.2022
KW - μ-gravity
KW - In-space manufacturing
KW - Additive manufacturing
KW - Microgravity
KW - Powder
PY - 2022
AN - OPUS4-54559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lanzino, Maria Carolina
A1 - Le, Long-Quan R. V.
A1 - Wilbig, Janka
A1 - Rheinheimer, Wolfgang
A1 - Seidenstuecker, Michael
A1 - Günster, Jens
A1 - Killinger, Andreas
T1 - Thin GB14 coatings on implants using HVSFS
N2 - Enhancing osseointegration, the process by which medical implants securely bond to bone, is crucial for improving patient outcomes in orthopedics and dental surgery. Calcium alkali orthophosphates, with their superior bioactivity, resorbability, and chemical resemblance to bone minerals, have emerged as promising candidates for implant coatings. These materials offer improved solubility and lower melting points due to the substitution of calcium with potassium and sodium, along with the addition of magnesium oxide. This study investigates GB14 calcium alkali orthophosphate coatings applied via High Velocity Suspension Flame Spraying (HVSFS), a technique that enables precise control over coating properties. A porosity target of >10% was set to promote bone growth, and we achieved porosities up to 13%, ensuring better cell penetration and stability at the implant-bone interface. Coatings were produced using different gas parameters and distances, with their microstructure and phase composition analyzed using scanning electron microscope (SEM), Vickers hardness testing and X-ray diffraction (XRD). Additionally, roughness and porosity were also assessed. Different coating’s microstructures were achieved by varying stand-off distance and gas parameters. Increasing stand-off distance while reducing gas stoichiometry enabled the production of calcium alkali orthophosphate coatings with fewer cracks, higher porosity and a hardness level comparable to that of state-of-the-art tricalcium phosphate (TCP) coatings. The sample with optimized properties in terms of achieved microstructure and topography was selected for in vitro testing using MG63 osteosarcoma cells to evaluate cell proliferation and adhesion. WST (I) assay, LDH assay, and live/dead staining confirmed the biocompatibility of the coatings, highlighting the potential of HVSFS to enhance osseointegration and outperform conventional methods in implantology. No relevant cytotoxicity could be shown and cells show a good proliferation over time. These results highlight thus the potential of HVSFS to produce thin, bioactive and resorbable coatings to enhance osseointegration.
KW - Bio ceramics
KW - Spray coating
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623983
DO - https://doi.org/10.3389/fmats.2024.1522447
SN - 2296-8016
VL - 11
IS - 1522447
SP - 1
EP - 14
PB - Frontiers Media SA
AN - OPUS4-62398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller-Elmau, Johanna
T1 - 2PP of ceramic – What’s next?
N2 - Photon-based additive manufacturing technologies such as SLA, DLP, LCM, moreover volumetric two-photon-polymerization (2PP), Xolography and holographic technologies promise the highest accuracy and dimensional freedom. To transfer the light through the feedstock it needs sufficient transparency. Ceramic particles used for powder processing routes act as scattering sites and therefore hinder the light transmission, unless…
The particle size and particle size distribution are chosen small and narrow enough. Particles smaller than roughly 1/10th of the light wavelength, mostly nanoparticles around 5nm size, decrease scattering vastly. This turns resins even with homogeneously distributed ceramic weight fraction of up to 80% transparent again. Feedstocks were prepared for the highly accurate two-photon-polymerization gaining the smallest yttria stabilized zirconia structures with a resolution of 500nm and unique mechanical properties.
The same feedstock was applied to DLP and LCM as layer-by-layer AM-technologies for bigger parts. Hybridizing both technologies enables ceramic parts with microscopic accuracy at macroscopic dimensions. The feedstock was even applied to the volumetric Xolography with the highest transparency requirement so far and to versatile and flexible holographic AM.
What are the next steps? Can those proof-of -concept studies be transferred to industrial applications and what are the hurdles on the way? How to make the stretch between fundamental research and application-oriented development?
T2 - ECERS
CY - Dresden, Germany
DA - 31.08.2025
KW - Tranparent
KW - Ceramic
KW - Two-photon-polymerization
PY - 2025
AN - OPUS4-64939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Wechselwirkungen in Geothermieanlagen - nicht nur ein Beständigkeitsaspekt
N2 - Um Konstrukteuren und Nutzern geothermischer Anlagen grundlegende Informationen über die Korrosionsbeständigkeit zur Verfügung zu stellen, wurden verschiedene metallische Werkstoffe, darunter nichtrostende Duplex- und austenitische Stähle sowie eine Nickellegierung, in künstlichen Geothermalwässern bewertet, die die Bedingungen an verschiedenen Standorten mit geothermischem Potenzial simulieren.
Mit Hilfe von elektrochemischen und Langzeittests wurde die Eignung verschiedener metallener Werkstoffe mittels kritischer Potentiale und Korrosionsraten untersucht.
In hochsalinaren Umgebungen erwies sich Spaltkorrosion als der entscheidende Mechanismus. Die Nickelbasislegierung zeigt eine ausgezeichnete Beständigkeit gegenüber Lochkorrosion. Abgesehen von ihren hohen Kosten eignet sie sich sehr gut für den Bau von Geothermieanlagen mit stark salzhaltigen Fluiden. Rostfreie Stähle und Duplexstähle weisen eine begrenzte Korrosionsbeständigkeit gegen Loch- und Spaltkorrosion auf. Daher sind sie für stark salzhaltige Fluide nicht geeignet. Der Superaustenit zeigt ein temperaturabhängiges Verhalten. In nichtsalinaren Umgebungen könnten niedrig legierte Stähle (neben den höher legierten Werkstoffen) als Konstruktionsmaterial für Geothermieanlagen eingesetzt werden, sofern eine ausreichende Wandstärke des Materials berücksichtigt wird.
Neben Korrosionsaspekten erwies sich auch die Ausfällung von Fluidbestandteilen als interessantes Thema. Beim Betrieb der Forschungsanlage in Groß Schönebeck wurden Kupfer- und Bleieffekte im Bohrloch festgestellt. Die auftretenden Mechanismen und Maßnahmen zur Verhinderung von Ausfällungen und Abscheidungen wurden ebenso untersucht, wie deren mögliche Einflüsse auf die Korrosionsbeständigkeit metallener Werkstoffe für Anlagenkomponenten.
Der Vortrag beschreibt die Wechselwirkungen zwischen Geothermalwässern und Ausrüstungs-komponenten.
T2 - Geothermiekongress 2024
CY - Potsdam, Germany
DA - 22.10.2024
KW - Örtliche Korrosion
KW - Edelstahl
KW - Geothermie
KW - Ni-Legierung
KW - Abscheidung
PY - 2024
AN - OPUS4-61441
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna Christiane
A1 - Schwentenwein, Martin
A1 - Bermejo, Raúl
A1 - Günster, Jens
T1 - Hybridizing Lithography-Based Ceramic Additive Manufacturing with Two-Photon-Polymerization
N2 - Stereolithography processes such as lithography-based ceramic manufacturing (LCM) are technologies that can produce centimeter-sized structures in a reasonable time frame. However, for some parts specifications, they lack resolution. Two-photon-polymerization (2PP) ensures the highest geometric accuracy in additive manufacturing so far. Nevertheless, building up parts in sizes as large as a few millimeters or even centimeters is a time-consuming process, which makes the production of 2PP printed parts very costly. Regarding feedstock specification, the requirements for 2PP are different to those for LCM, and generally, feedstocks are designed to meet requirements for only one of these manufacturing technologies. In an attempt to fabricate highly precise ceramic components of a rather large size, it is necessary to develop a feedstock that suits both light-based technologies, taking advantage of LCM’s higher productivity and 2PP’s accuracy. Hybridization should bring the desired precision to the region of interest on reasonably large parts without escalating printing time and costs. In this study, specimens gained from a transparent feedstock with yttria stabilized zirconia (YSZ) particles of 5 nm at 70 wt% were presented. The resin was originally designed to suit 2PP, while being also printable with LCM. This work demonstrates how hybrid parts can be sintered into full YSZ ceramics.
KW - Additive Manufacturing
KW - Transparent ceramic
KW - Nano-powder
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584541
DO - https://doi.org/10.3390/app13063974
SN - 2076-3417
VL - 13
IS - 6
SP - 1
EP - 9
PB - MDPI
CY - Basel
AN - OPUS4-58454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Almalla, A.
A1 - Hertwig, Andreas
A1 - Fischer, Daniel
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - Development of layer-by-layer assembled thin coatings on aluminium alloy AA2024-T3 for high resolution studies of local corrosion processes
N2 - The aim of this study is to develop nanometer-thin epoxy-based films on aluminium alloy AA2024-T3 as a model coating system for high resolution corrosion studies. Spin coating was used for the layer-by-layer (LbL) deposition of poly-(ethylenimine) (PEI) and poly([o-cresyl glycidyl ether]-co-formaldehyde) (CNER) bilayers. The film chemistry and the cross-linking process were characterized by means of Fourier-transform infrared spectroscopy (FTIR).
Ellipsometric data confirmed the linear increase of film thickness. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicate the improvement of the film barrier properties with increasing film thickness. Mapping of the topography and the volta potential was performed by means of scanning Kelvin probe force microscopy (SKPFM).
The results indicate the presence of a homogeneous film structure, while the intermetallic phases can still be identified below the coating. The SKPFM Analysis confirmed that the model films are suitable for investigation of corrosion processes at the coating/metal interface.
KW - Spectroscopy
KW - Coatings
KW - Electrochemistry
KW - Microscopy
KW - Resins
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514627
DO - https://doi.org/10.1002/app.49826
SN - 0021-8995
VL - 137
IS - 48
SP - e49826-1
EP - e49826-9
PB - Wiley
CY - New York, NY
AN - OPUS4-51462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Wasserstoffdiffusion und lokale Volta-Potentiale in Hoch- und Mittelentropie-Legierungen
N2 - Hochentropie-Legierungen (HEAs) zeichnen sich durch einen Mischkristall-System aus mindestens fünf und Mittelentropie-Legierungen (MEAs) durch mindestens drei Hauptlegierungselemente aus, in äquiatomarer Zusammensetzung. Sie zeigen außergewöhnliche Anwendungseigenschaften, wie z.B. hohe Festigkeit, Duktilität oder Korrosionsbeständigkeit. Zukünftige HEA/MEA-Komponenten aufgrund ihrer Eigenschaften für wasserstoffhaltige Umgebungen (wie Behälter für kryogene oder Hochdruckspeicherung) von Interesse. Daher ist die Bewertung der Wasserstoffabsorption und die Diffusion in diesen Materialien von großer Bedeutung. Dazu wurden in unserer Studie eine CoCrFeMnNi-HEA und eine CoCrNi-MEA untersucht. Die Proben wurden elektrochemisch mit Wasserstoff beladen. Für die Ermittlung des Wasserstoffdiffusionsverhaltens wurde die thermische Desorptionsanalyse (TDA) mit unterschiedlichen Heizraten bis zu 0,250 K/s angewandt. Die nachfolgende Peakentfaltung der Signale führte zu Hochtemperatur-Desorptionsspitzen und Wasserstofftrapping auch über 280°C. Eine resultierende Gesamtwasserstoffkonzentration > 40 ppm wurde für den MEA ermittelt und > 100 ppm für den HEA. Dies deutet auf zwei wichtige Effekte hin:
(1) verzögerte Wasserstoffdiffusion und (2) eine beträchtliche Menge an getrapptem Wasserstoff auch bei hoher Temperatur. Beide Effekte können hinsichtlich einer wasserstoffunterstützten Rissbildung kritisch werden, dies erfordert jedoch weitere Untersuchungen. Zusätzlich erfolgte die Bestimmung des lokalen Volta-Potentials mittels hochauflösender Kelvin-Sonden-Kraft-Mikroskopie (SKPFM). Die ermittelten Scans zeigen einen bestimmten Einfluss der Wasserstoffbeladung auf die Potentiale.
T2 - Symposium on Materials and Joining Technology
CY - Online meeting
DA - 07.09.2020
KW - Wasserstoff
KW - High-entropy alloy
KW - Diffusion
KW - Scanning kelvin probe force microscopy
KW - Thermal desorption analysis
PY - 2020
AN - OPUS4-51187
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Preliminary Study on Al2O3 Sol-Gel Coating for Corrosion Protection of Martensitic Stainless Steel in Artificial Geothermal Water
N2 - Al2O3 coatings are often used as protective layers on steels against electrochemical and high-temperature corrosion because they are chemically inert and stable at elevated temperatures. This study presents preliminary work on the possibilities of using Al2O3 sol-gel coatings for corrosion protection of martensitic stainless steels in geothermal environments. Al2O3 sol-gel coatings were applied on UNS S42000, which is known to be susceptible to uniform and localized corrosion. The coated steel specimens were then tested in two types of artificial geothermal water, which simulate the geothermal fluids found in Sibayak (SBY), Indonesia, and North German Basin (NGB), Germany, respectively. SBY has pH 4 and 1.5 g/L of chloride ions, whereas NGB has a pH of 6 and 166 g/L of chloride ions. All experiments were carried out in autoclaves at 150 °C and 1 MPa under the deaerated condition. Evaluations were performed by investigating the surface profiles of both uncoated and coated steels before and after the corrosion test using a Laser Scanning Microscope (LSM) and Scanning Electron Microscope (SEM). Finally, Electrochemical Impedance Spectroscopy (EIS) was performed to compare the corrosion resistance of Al2O3 coated steels in SBY and NGB solutions. It was observed from the corrosion test that Al2O3 coatings are more suitable for use in the geothermal water with a higher pH.
T2 - AMPP Annual International Corrosion Conference 2021
CY - Online Meeting
DA - 19.04.2021
KW - Protective coating
KW - Sol-gel coating
KW - Geothermal
KW - Martensitic steel
KW - Corrosion
PY - 2021
AN - OPUS4-52500
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - Morell, Daniel
A1 - von der Au, Marcus
A1 - Wittstock, Gunther
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - Transpassive Metal Dissolution vs. Oxygen Evolution Reaction: Implication for Alloy Stability and Electrocatalysis
T1 - Transpassive Metallauflösung vs. Sauerstoffentwicklung:
Auswirkungen auf Legierungsstabilität und Elektrokatalyse
N2 - Multi-principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER-onset detection, and quantitative chemical analysis with inductively coupled-mass spectrometry (ICP-MS) and ultraviolet visible light (UV-Vis) spectroscopy to elucidate metal dissolution processes. In-situ electrochemical atomic force microscopy (EC-AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors.
N2 - Multi-Hauptelement-Legierungen (MPEAs) gewinnen in der Korrosions- und Elektrokatalyseforschung aufgrund ihrer elektrochemischen Stabilität über einen breiten pH-Bereich und der Vielfalt der möglichen chemischen Zusammensetzungen zunehmend an Interesse. In unseren Untersuchungen mit der äquimolaren CrCoNi-Legierung in einem sauren Elektrolyten (0.1 M NaCl, pH 2) beobachteten wir eine signifikante Metallauflösung, die mit der Sauerstoffentwicklungsreaktion (OER) im transpassiven Bereich einhergeht, obwohl in zyklischen Polarisationskurven keine Hysterese auftrat oder andere offensichtliche Korrosionsindikatoren vorlagen. In diesem Artikel wird ein Charakterisierungskonzept eingeführt, dass die Beiträge der OER und der Legierungsauflösung differenziert. Hierfür kommt die elektrochemische Rastermikroskopie (SECM) zum Nachweis des Beginns der OER und die quantitative chemische Analyse mit induktiv gekoppelter Massenspektrometrie (ICP-MS) und UV/Vis-Spektrometrie zur Aufklärung der Metallauflösungsprozesse zum Einsatz. Die elektrochemische In situ-Atomkraftmikroskopie (EC-AFM) zeigte, dass die intergranulare Korrosion der dominierende Mechanismus der transpassive Metallauflösung von CrCoNi ist. Diese Ergebnisse besitzen erhebliche Auswirkungen für die Beurteilung der Stabilität von MPEAs in Korrosionssystemen und der Stromausbeute von OER-Katalysatoren auf der Basis von MPEAs. Die Daten unterstreichen die Notwendigkeit der analytischen Bestimmung von Metallionen, die von MPEA-Elektroden freigesetzt werden. Die Freisetzung von Übergangsmetallionen verringert nicht nur die Stromausbeute von Elektrolyseuren, sondern kann zu einer Schädigung von Membranen in elektrochemischen Reaktoren führen.
KW - Transpassive dissolution
KW - Corrosion
KW - Multi-prinicpal element alloys (MPEAs)
KW - Passivation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597045
DO - https://doi.org/10.1002/anie.202317058
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-59704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rütters, H.
A1 - Fischer, S.
A1 - Le, Quynh Hoa
A1 - Bettge, Dirk
A1 - Bäßler, Ralph
A1 - Maßmann, J.
A1 - Ostertag-Henning, C.
A1 - Lennard Wolf, J.
A1 - Pumpa, M.
A1 - Lubenau, U.
A1 - Knauer, S.
A1 - Jaeger, P.
A1 - Neumann, A.
A1 - Svensson, K.
A1 - Pöllmann, H.
A1 - Lempp, C.
A1 - Menezes, F.
A1 - Hagemann, B.
T1 - Towards Defining Reasonable Minimum Composition Thresholds – Impacts of Variable CO2 Stream Compositions on Transport, Injection and Storage
N2 - The collaborative project “Impacts of impurities in CO2 streams captured from different emitters in a regional cluster on transport, injection and storage (CLUSTER)” aimed to set up recommendations on how to define “reasonable minimum composition thresholds” that CO2 streams should meet when accessing CO2 transport pipeline networks. Within CLUSTER, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the whole CCS chain. Investigations included, amongst others, impacts on:
• corrosion of pipeline steel,
• pipeline network design and related transport costs,
• alteration of well bore cements,
• pressure development and rock integrity,
• geochemical reactions, and
• petrophysical and geomechanical rock properties.
All investigations are based on a generic CCS chain scenario. In this scenario, CO2 streams are captured from a spatial cluster of eleven emitters and collected in a regional pipeline network. Emitters comprise seven fossil fuel-fired power plants equipped with different capture technologies, two cement plants, one refinery and one integrated iron and steel plant. In total, 19.78 Mio t CO2 (including impurities) are captured in the emitter cluster annually. The combined CO2 stream is transported in a trunk line with a length of 400 km (100 km of these offshore) and is injected into five generic storage structures. The storage reservoirs are saline aquifers of the Buntsandstein.
The investigations revealed beneficial and deteriorating impacts of different impurities and combinations thereof. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the modelled variable compositions and mass flow rates were observed. Based on the results, the CLUSTER project team recommends not to define “minimum composition thresholds” for CO2 streams as strict threshold values for each individual impurity in the stream. Instead, CO2 stream compositions and variabilities for specific CCS projects should be constrained with regard to a set of parameters including i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of CO2 stream composition, and iv) impurity combinations to be avoided.
T2 - The 15th Greenhouse Gas Control Technologies Conference
CY - Online meeting
DA - 15.03.2021
KW - Corrosion
KW - Impurities
KW - CO2 quality
KW - Pipeline network
KW - Whole-chain CCS scenario
KW - Recommendations
PY - 2021
DO - https://doi.org/10.2139/ssrn.3816427
SP - 1
EP - 18
PB - Elservier
AN - OPUS4-52940
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna C.
A1 - Riechers, Birte
A1 - Pauw, Brian Richard
A1 - Maaß, Robert
A1 - Günster, Jens
T1 - Microplastic response of 2PP‐printed ceramics
N2 - AbstractTwo‐photon polymerization (2PP) additive manufacturing (AM) utilizes feedstocks of ceramic nanoparticles of a few nanometers in diameter, enabling the fabrication of highly accurate technical ceramic design with structural details as small as 500 nm. The performance of these materials is expected to differ from conventional AM ceramics, as nanoparticles and three‐dimensional printing at high resolution introduce new microstructural aspects. This study applies 2PP‐AM of yttria‐stabilized zirconia to investigate the mechanical response behavior under compressive load, probing the influence of smallest structural units induced by the line packing during the printing process, design of sintered microblocks, and sintering temperature and thereby microstructure. We find a dissipative mechanical response enhanced by sintering at lower temperatures than conventional. The pursued 2PP‐AM approach yields a microstructured material with an increased number of grain boundaries that proposedly play a major role in facilitating energy dissipation within the here printed ceramic material. This microplastic response is further triggered by the filigree structures induced by hollow line packing at the order of the critical defect size of ceramics. Together, these unique aspects made accessible by the 2PP‐AM approach contribute to a heterogeneous nano‐ and microstructure, and hint toward opportunities for tailoring the mechanical response in future ceramic applications.
KW - Manufacturing
KW - Mechanical properties
KW - Microstructure
KW - Plasticity
KW - Zirconia: yttria stabilized
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605176
DO - https://doi.org/10.1111/jace.19849
SN - 1551-2916
VL - 107
IS - 10
SP - 6636
EP - 6645
PB - Wiley
CY - Oxford
AN - OPUS4-60517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Corrosion‐Resistant Linings and Coatings
N2 - This book introduces to aspects to be considered when dealing with coatings and linings. Philip A. Schweitzer covers and compares a variety of specific coatings and their applications. In 18 chapters he divided the content into two main parts: linings and coatings.
All professionals involved in design and maintenance processes get by this book a compact survey of necessary considerations which needs to be done when applying surface protection measures. The literature references at the end of some chapters support the readers finding additional information about the special topic, mainly written by the author himself. Since this newly issued paperback edition is a 1:1 re‐print of the 2001 hardcover version, neither current publications are referenced, nor revisions were made.
KW - Corrosion
KW - Lining
KW - Coating
KW - Elastomer
PY - 2020
DO - https://doi.org/10.1002/maco.202070094
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 9
SP - 1592
EP - 1593
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, Juan-Carlos
A1 - Baasch, Julian
A1 - Stapperfend, Simon
A1 - Facchini, Leonardo
A1 - Linke, Stefan
A1 - Stoll, Enrico
A1 - Günster, Jens
T1 - Laser Melting vs. Laser Sintering: Large Area Heat Processing of Lunar South Pole Simulant
N2 - A key component of future lunar missions is the concept of In-Situ Resource Utilization (ISRU), which involves the use of local resources to support human missions and reduce dependence on Earth-based supplies. This paper investigates the thermal processing capability of lunar regolith without the addition of binders, with a focus on large-scale applications for the construction of lunar habitats and infrastructure. The study used a simulant of lunar regolith found on the Schrödinger Basin in the South Pole region. This regolith simulant consists of 20 wt% basalt and 80 wt% anorthosite. Experiments were conducted using a high power CO2 laser to sinter and melt the regolith in a 80 mm diameter laser spot to evaluate the effectiveness of direct large area thermal processing. Results indicated that sintering begins at approximately 1,180 °C and reaches full melt at temperatures above 1,360 °C. Sintering experiments with this material revealed the formation of dense samples up to 11 mm thick, while melting experiments successfully produced larger samples by overlapping molten layers and additive manufacturing up to 50 mm thick. The energy efficiency of the sintering and melting processes was compared. The melting process was about 10 times more energy efficient than sintering in terms of material consolidation, demonstrating the promising potential of laser melting technologies of anorthosite-rich regolith for the production of structural elements.
KW - Additive Manufacturing
KW - Laser melting
KW - ISRU
KW - Moon
KW - Regolith
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639614
DO - https://doi.org/10.1016/j.amf.2025.200226
SN - 2950-4317
VL - 4
IS - 3
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-63961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brandić Lipińska, M.
T1 - PAVER - Contextualizing laser sintering within a lunar technology roadmap
N2 - The Global Exploration Strategy of the International Space Exploration Coordination Group (ISECG) describes a timeframe of 2020 and beyond with the ultimate aim to establish a human presence on Mars towards the 2040ies. The next steps lie on the Moon with a focus on the coming 10 years. Early lunar surface missions will establish a capability in support of lunar science and prepare and test mission operations for subsequent human exploration of Mars and long-duration human activities on the Moon.
Given the extreme costs involved in the shipping of material from Earth, a prerequisite for future human exploration is the manufacturing of elements directly on the Moon’s surface. Unlike the equipment, which at the beginning will have to be brought from Earth, raw materials and energy could be available following the concept of In-Situ Resource Utilization. The ESA OSIP PAVING THE ROAD (PAVER) study investigates the use of a laser to sinter regolith into paving elements for use as roadways and launch pads thus mitigating dust issues for transport and exploration vehicles.
The ESA-funded study examines the potential of using a laser (12 kW CO2 laser with spot beam up to 100 mm) for layer sintering of lunar and martian regolith powders to manufacture larger 3D elements and provide know-how for the automatic manufacture of paving elements in the lunar environment. The project contributes to the first step toward the establishment of a lunar base and will lead to the construction of equipment capable of paving areas and manufacturing 3D structures.
PAVER project sets the starting point for an examination of the larger context of lunar exploration. Mission scenarios will look at different phases of lunar exploration: Robotic Lunar Exploration, Survivability, Sustainability, and Operational Phase. A proposed Technology Roadmap investigates the mission scenario and analyses how, and to which extent, laser melting/sintering will play a role in the various phases of exploration. The paper contextualizes laser sintering within selected mission scenarios and discusses the different kinds of infrastructure that can be produced at each phase of the mission. The outcome of the study includes the detailing of the TRL steps in the project and an outline of a timeline for the different elements. Covered aspects include terrain modelling such as operation pads, roadways, or towers, non-pressurized building structures to protect machinery, and habitat envelopes, to protect and shield humans against dust, micrometeoroids, and radiation.
T2 - 73rd International Astronautical Congress (IAC)
CY - Paris, France
DA - 18.09.2022
KW - Additive manufacturing
KW - ISRU
KW - Infrastructure
KW - Lunar habitat
KW - Paving
KW - Solar sintering
PY - 2022
AN - OPUS4-56529
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - Additive Manufacturing for dental restorations by layerwise slurry deposition (LSD-print) technology
N2 - The growing market of custom-made dental restorations offers a major potential for an application of ceramic additive manufacturing (AM).
The possibility to individualize patient specific design and to establish new efficient workflows, from model generation to manufacturing, can be fully exploited by AM technologies. However, for mass customization to be truly envisioned, ceramic AM needs to achieve a level of maturity, aesthetic quality, and productivity comparable to established manufacturing processes.
In this presentation, the potential of the “layerwise slurry deposition” LSD-print technology for dental applications will be explored. It has been shown in the past years that the LSD-print can be applied to advanced ceramic materials such as alumina and silicon-infiltrated silicon carbide. For these materials, the LSD-print technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics.
The current development deals with the challenges of applying this technology to a feldspar dental material, comparing the quality of AM restorations with the equivalent material for an established CAD/CAM workflow.
Preliminary results not only indicate that the AM material produced by LSD-print can be competitive in terms of mechanical properties, but also that aesthetically satisfactory restorations can be manufactured for veneers, inlays and onlays as well as single unit fixed dental prostheses (FDPs).
The presentation focuses on the material and technological challenges alongside the process chain, from the printing process, to debinding, firing and finishing the restorations.
T2 - XVIIIth Conference of the European Ceramic Society
CY - Lyon, France
DA - 02.07.2023
KW - Additive Manufacturing
KW - Layerwise slurry deposition
KW - dental
KW - ceramic
PY - 2023
AN - OPUS4-58469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
A1 - Sänger, Johanna
A1 - Pauw, Brian Richard
T1 - Tailoring powder properties for the light based volumetric additive manufacture of Ceramics
N2 - Manipulating ceramic powder compacts and ceramic suspensions (slurries) within their volume with light requires a minimum transparency of the materials. Compared to polymers and metals, ceramic materials are unique as they offer a wide electronic band gap and thus a wide optical window of transparency. The optical window typically ranges from below 0.3 µm up to 5µm wavelength. Hence, to penetrate with light into the volume of a ceramic powder compound, its light scattering properties need to be investigated and tailored. In the present study we introduce the physical background and material development strategies to apply two-photon-polymerization (2PP), and other volumetric methods for the additive manufacture of filigree structures within the volume of ceramic slurries.
T2 - ICACC 2024
CY - Daytona Beach, Florida, USA
DA - 28.01.2024
KW - Additive Manufacturing
KW - Two Photon Polymerization
KW - Advanced ceramics
PY - 2024
AN - OPUS4-59889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Frost, K.
A1 - Lüth, Peter
A1 - Schmidt, Martin
A1 - Simon, K.
A1 - Uhlig, S.
T1 - Interlaboratory test 2023 on the method DIN EN 15188:2021-07 "Determination of the spontaneous ignition behaviour of dust accumulations" - Final report of results
N2 - The test method DIN EN 15188:2021-07 “Determination of the spontaneous ignition behaviour of dust accumulations” is applied to characterize the self-ignition behaviour of combustible dusts. The experimental basis for describing the self-ignition behaviour of a given dust is the determination of the self-ignition temperatures (TSI) of differently-sized volumes of the dust sample by isoperibolic hot storage experiments (storage at constant oven temperatures) in commercially available ovens. The results measured this way reflect the dependence of the self-ignition temperatures on the volume of a dust accumulation.
Several internal investigations in the past (e.g. interlaboratory tests in 2010-2011 and 2015-2016) have shown significant differences between the lab-specific results of hot storage tests of the former version of the revised DIN EN 15188:2021-07 (DIN EN 15188:2007). Therefore, an improvement of the test method DIN EN 15188:2007 was necessary.
After a rather long and extensive series of various improvements (methodological modifications), the interlaboratory test in 2015-2016 demonstrated an acceptable reliability of the test method and a satisfactory measurement uncertainty if the modifications described in the interlaboratory test are taken into account. On the basis of this interlaboratory test in 2015, this subsequently led to a revision of the standard, whereby, in addition to the methodological improvements, the measurement uncertainty to be taken into account could now also be specified for the first time in this standard. The revised DIN EN 15188:2021-07 was published in 2021 and can now be applied by laboratories.
This report provides the laboratory results of the first interlaboratory test 2023 on the revised method DIN EN 15188:2021-07 and summarizes the results of the assessment of laboratory performance.
KW - DIN EN 15188:2021-07
KW - Spontaneous ignition
KW - Interlaboratory test
KW - Round robin test
KW - Proficiency test
KW - Dangerous goods
KW - Hazardous substances
KW - Measurement uncertainty
KW - Gefahrgut
KW - Gefahrstoff
KW - Qualitätssicherung
KW - Ringversuch
KW - Selbstentzündung
KW - Staub
KW - Dust
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614560
SN - 978-3-9818564-6-0
DO - https://doi.org/10.26272/opus4-61456
SP - 1
EP - 51
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
ET - 1.
AN - OPUS4-61456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Kuchenbecker, Petra
A1 - Lindemann, Franziska
T1 - Final report proficiency test LS BAM-5.5-2021: Measurement of the particle size distribution of ceramic powders by laser diffraction in accordance with ISO 13320
N2 - This is the final report on the proficiency test (PT) „Measurement of the particle size distribution of ceramic powders by laser diffraction”. The PT was organized by the Federal Institute for Materials Research and Testing (BAM), division 5.5 “Advanced technical ceramics”. The measurements took place from 12/2021 to 03/2022. The aim of the interlaboratory comparison was the proficiency assessment of the participating laboratories.
Management and realization of PT were performed in accordance with DIN EN ISO/IEC 17043:2010.
The basis of the harmonized measuring procedure and the instructions for the interlaboratory comparison was the standard ISO 13320:2020.
The statistical analysis was performed in accordance with DIN ISO 13528:2020 by use of the software PROLab Plus (QuoData GmbH, Dresden, Germany).
A group of 44 laboratories from 17 countries participated in the PT. Laser diffraction analyzers produced by 7 different manufacturers were used. The three test materials were commercial products. Overall, the measured characteristic values of the particle distributions (d10, d50 and d90) were in the size range between 0.5 and 25 μm. The final report contains all individual results in an anonymous way.
KW - Proficiency test
KW - Particle size
KW - Laser light scattering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548640
DO - https://doi.org/10.26272/opus4-54864
SP - 1
EP - 33
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Breese, Philipp Peter
T1 - Additive Manufacturing with In-situ Measurement and Closed-loop Control for the Powder Flow in Laser Metal Deposition
N2 - The powder mass flow rate is one of the three main factors directly influencing geometry and quality in the Additive Manufacturing (AM; also 3D printing) process of Laser Metal Deposition (LMD), also known as Directed Energy Deposition (DED-LB/M). However, the pneumatic transport of the metal powder lacks stability, repeatability, and traceability. There is currently no reliable in-situ measurement of the mass flow rate available in industry. As a result, time-consuming powder flow measurements before the manufacturing are typical while no recording or feedback takes place during the manufacturing. Based on this problem statement, this thesis introduces a holistic approach for in-situ measurement and closed-loop control of pneumatic powder flows. For the in-situ measurement, a widely available nonintrusive optoelectronic sensor was used. Found mathematical dependencies reliably convert the sensor output into a powder mass flow rate dependent on powder parameters and feeding conditions. Therefore, the model is usable with various powder types while achieving a Mean Relative Error (MRE) of less than 4% at 125 Hz. Similarly, a model was introduced for the powder velocity using a second sensor further downstream. This provided insight into the powder’s movement while the model achieved an MRE of less than 3%.
As a second main research endeavor, the sensor output was used to implement and investigate a closed-loop powder flow control on a vibration feeder. PID controller gains were calculated empirically at set operating points for the nonlinear system. Again, a usage with various metal powders is possible as the influences of powder parameters and feeding conditions were investigated and incorporated into the model. In addition, the dependence on the previous powder flow (memory effect) was factored in as well. With this, faster recovery from blockages and a reduction in standard deviation during steady state feeding by more than 20% were demonstrated.
Complementary numerical CFD simulations investigated the effect of the carrier gas flow rates on powder flow homogeneity and powder particle size separations. A second modeling approach demonstrated the use of machine learning with the optoelectronic sensor output. A 1D convolutional neural network (CNN) was shown to be able to predict the powder flow with a Weighted Absolute Percentage Error (WAPE) of less than 4% compared to the actual flow. With this, the model’s capability to detect slightly elevated moisture (at <0.4wt%) in the powder as well as differences in particle size distribution was proven on in-situ data from powder feeding.
Finally, the methods were validated on the LMD process by additively manufacturing test components. The active closed-loop powder flow control shows a significant improvement in repeatability for LMD. The in-situ measurement allows a monitoring of the powder mass flow rate with the recorded data throughout the entire AM process. In addition, Scanning Electron Microscopy (SEM) images showed potential benefits at the microscopic level like reduced defects.
With this, the whole chain for a powder flow improvement method was investigated, implemented, and validated in the context of Laser Metal Deposition. Furthermore, a high potential for retrofitting is given while at low cost. This lays the foundation for a more traceable and digital AM process in industry leading to repeatable and safe products.
KW - Pneumatic powder flow
KW - Direct Energy Deposition
KW - DED-LB/M
KW - 3D printing
KW - In-situ monitoring
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650261
DO - https://doi.org/10.14279/depositonce-23032
SP - 1
EP - 198
PB - TU Berlin
CY - Berlin
AN - OPUS4-65026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hahn, Marc Benjamin
T1 - Temperature effects in the Object Oriented Micromagnetic Framework (OOMMF) - OOMMF input parameter files for Tc determination
N2 - To simulate the movement of the macroscopic magnetic moment in ferromagnetic systems under the influence of elevated temperatures, the stochastic version of the Landau-Lifshitz (LL) or the Landau-Lifshitz-Gilbert equation with a spin density of one per unit cell has to be used.
To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion has to be performed. OOMMF sample files MIF) are provided which can be used to determine the Curie temperature for the classical bulk magnets, iron, nickel and cobalt.
KW - OOMMF
KW - Temperature
KW - Micromagnetism
KW - Thetaevolve
KW - Ferromagnetism
KW - Exchange interaction
KW - LLG
KW - Landau Lifshitz equation
KW - Magnetic moment
KW - Magnetic nanoparticles
KW - Object oriented micromagnetic framework
KW - Stochastic Landau Lifshitz Gilbert equation
KW - Temperature scaling
PY - 2020
DO - https://doi.org/10.26272/opus4-51169
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-51169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hahn, Marc Benjamin
T1 - TOPAS cell model with nanoparticles
N2 - These files contain cell models for TOPAS/Geant4 and the inclusion of nano particles in particle scattering simulations. A simple spherical cell with nanoparticles can be generated in a fast manner. The user has the option to include the following organelles: nucleus, mitochondria, cell membrane. Additionally nanoparticles can be included in the cytosol and at the surface of the nucleus and/or the mitochondria.
The C++ classes in this repository extend the functionality of the TOPAS (http://www.topasmc.org/) Monte-Carlo program, which is itself a wrapper of the Geant4 MCS Toolkit (http://geant4.org). The sourcecode together with examples and scorers are provided.
"If you use this extension please cite the following literature:
Hahn, M.B., Zutta Villate, J.M. "Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement in cell organelles." Sci Rep 11, 6721 (2021).
https://doi.org/10.1038/s41598-021-85964-2 "
KW - Monte-Carlo simulation
KW - MCS
KW - Geant4
KW - TOPAS
KW - TOPAS-nBio
KW - Dosimetry
KW - Nanoparticles
KW - Nanoparticle
KW - AuNP
KW - Gold
KW - Microdosimetry
KW - Targeted nanoparticle
KW - Simulation
KW - Particle scattering
KW - Cell
KW - Nucleus
KW - Mitochondria
KW - Cancer therapy
KW - Radiation therapy
PY - 2020
UR - https://github.com/BAMresearch/TOPAS-CellModels
UR - https://github.com/MarcBHahn/TOPAS-CellModels
DO - https://doi.org/10.26272/opus4-51150
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-51150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Kuchenbecker, Petra
A1 - Lindemann, Franziska
T1 - Final report proficiency test LS BAM-5.4-2024 - Measurement of the particle size distribution of ceramic powders by laser diffraction
N2 - This publication is the final report on the proficiency test (PT) LS BAM-5.4-2024 „Measurement of the particle size distribution of ceramic powders by laser diffraction”. The PT was organized by the Federal Institute for Materials Research and Testing (BAM), division 5.4 “Advanced Multi-materials Processing”, Germany. The measurements took place from 2024/05 to 2024/07. The aim of the interlaboratory comparison was the proficiency assessment of the participating laboratories. The PT was performed in accordance with DIN EN ISO/IEC 17043:2010. The harmonized measurement procedure was based on ISO 13320:2020The statistical analysis was performed in accordance with DIN ISO 13528:2020 by use of the software PROLab (QuoData GmbH, Dresden, Germany). A group of 35 laboratories from 14 countries participated in the PT. Laser diffraction analyzers produced by 7 different manufacturers were used. The three test materials were commercial ceramic powders. Overall, the measured characteristic values of the particle size distributions (d10,3, d50,3 and d90,3) were in the size range between 1 and 35 μm. The final report contains all individual results in an anonymous form.
KW - Proficiency test
KW - Particle size determination
KW - Laser diffraction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610602
DO - https://doi.org/10.26272/opus4-61060
SP - 1
EP - 33
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61060
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - The human factor: A round robin study on the variation in data analyses
N2 - This is a remote presentation I gave at the 2022 Small-angle Scattering conference in Campinas, Brazil. The video has been obtained from the conference organisers with their explicit permission for use on YouTube. I've tried to spruce up the audio from the remote recording the best I could.
The conference abstract for this talk was:
"How much do we, the small-angle scatterers, influence the results of an investigation? What uncertainty do we add by our human diversity in thoughts and approaches, and is this significant compared to the uncertainty from the instrumental measurement factors?
After our previous Round Robin on data collection, we know that many laboratories can collect reasonably consistent small-angle scattering data on easy samples. To investigate the next, human component, we compiled four existing datasets from globular (roughly spherical) scatterers, each exhibiting a common complication, and asked the participants to apply their usual methods and toolset to the quantification of the results (https://lookingatnothing.com/index.php/archives/3274).
Accompanying the datasets was a modicum of accompanying information to help with the interpretation of the data, similar to what we normally receive from our collaborators. More than 30 participants reported back with volume fractions, mean sizes and size distribution widths of the particle populations in the samples, as well as information on their self-assessed level of experience and years in the field.
While the Round Robin is still underway (until the 25th of April, 2022), the initial results already show significant spread in the results. Some of these are due to the variety in interpretation of the meaning of the requested parameters, as well as simple human errors, both of which are easy to correct for. Nevertheless, even after correcting for these differences in understanding, a significant spread remains. This highlights an urgent challenge to our community: how can we better help ourselves and our colleagues obtain more reliable results, how could we take the human factor out of the equation, so to speak?
In this talk, we will introduce the four datasets, their origins and challenges. Hot off the press, we will summarize the anonymized, quantified results of the Data Analysis Round Robin. (Incidentally, we will also see if a correlation exists between experience and proximity of the result to the median). Lastly, potential avenues for improving our field will be offered based on the findings, ranging from low-effort yet somehow controversial improvements, to high-effort foundational considerations."
T2 - International Small-Angle Scattering Conference (SAS2022)
CY - Campinas, Brazil
DA - 11.09.2022
KW - Round robin
KW - Data analysis
KW - X-ray scattering
KW - Neutron scattering
KW - Nanomaterials
KW - Metrology
KW - Interlaboratory comparison
PY - 2023
UR - https://www.youtube.com/watch?v=t1Rowo--Osg
DO - https://doi.org/10.26272/opus4-56897
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-56897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Völker, Christoph
T1 - WEBSLAMD
N2 - The objective of SLAMD is to accelerate materials research in the wet lab through AI. Currently, the focus is on sustainable concrete and binder formulations, but it can be extended to other material classes in the future.
1. Summary
Leverage the Digital Lab and AI optimization to discover exciting new materials Represent resources and processes and their socio-economic impact.
Calculate complex compositions and enrich them with detailed material knowledge. Integrate laboratory data and apply it to novel formulations. Tailor materials to the purpose to achieve the best solution.
Workflow
Digital Lab
Specify resources: From base materials to manufacturing processes – "Base" enables a detailed and consistent description of existing resources
Combine resources: The combination of base materials and processes offers an almost infinite optimization potential. "Blend" makes it easier to design complex configurations.
Digital Formulations: With "Formulations" you can effortlessly convert your resources into the entire spectrum of possible concrete formulations. This automatically generates a detailed set of data for AI optimization.
AI-Optimization
Materials Discovery: Integrate data from the "Digital Lab" or upload your own material data. Enrich the data with lab results and adopt the knowledge to new recipes via artificial intelligence. Leverage socio-economic metrics to identify recipes tailored to your requirements.
KW - Materials informatics
KW - Scientific software
KW - Sequential learning
PY - 2022
UR - https://github.com/BAMresearch/WEBSLAMD
DO - https://doi.org/10.26272/opus4-56640
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-56640
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Schwibbert, Karin
A1 - Richter, Anja
A1 - Bonse, Jörn
T1 - BioCombs4Nanofibers: From nanofibers over spiders to bacteria
N2 - This 6 minute long MP4-video presents some key results of the European research project "BioCombs4Nanofibers" to the broader public. Inspired by nature, some concepts of certain types of spiders are transferred to technology in order to develop bacteria-repellent surfaces through laser surface nanostructuring.
Funding notice: This study was funded by the European Union's research and innovation program under the FET Open grant agreement No. 862016 (BioCombs4Nanofibers, http://biocombs4nanofibers.eu).
KW - Antiadhesive surfaces
KW - Laser-induced periodic surface structures (LIPSS)
KW - Cribellate spiders
KW - Bacterial adhesion tests
KW - Bacteria-repellent surfaces
PY - 2022
UR - https://download.jku.at/org/7kM/xyU/BioCombs4Nanofibers/D5.6_video%20for%20the%20broader%20public_23.03.2022.mp4
UR - https://www.jku.at/en/biocombs4nanofibers/dissemination/
DO - https://doi.org/10.26272/opus4-54939
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Katrin
A1 - Kraft, Sebastian
A1 - Weise, Matthias
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - X-ray emission during ultrafast laser grooving
N2 - Ultrashort pulse lasers offer the possibility to process materials with minimal heat input and high precision. However, the X-ray emission at high laser peak intensities represents an undesirable side effect. A laser system (1030 nm wavelength, 40 W maximum average laser power, 925 fs pulse duration, 100 μJ maximum pulse energy, 400 kHz pulse repetition frequency) was used to analyze the X-ray skin dose rates for applied peak intensities between 9.2 × 10^12 W/cm^2 and 1.3 × 10^14 W/cm^2 for mild steel, stainless steel and tungsten during groove processing. The lowest laser peak intensity at which X-ray emission could be measured was 9.2 × 10^12 W/cm^2 for processing of stainless steel. The X-ray emission showed a characteristic evolution in dependence on the number of overscans at the same line positions. For low peak intensities, a measurable X-ray emission only begins after a few passes. The number of scans to reach the maximum dose rate increases with lower laser peak intensity. Analysis of the evolving surface topography by white light interference microscopy in connection with ray-tracing simulations led to the interpretation that the increase in X-ray emission is due to the local intensity redistribution by multiple reflection within the laser-generated grooves which is promoted by a particular choice of the linear laser polarization.
KW - Ultrashort pulsed laser
KW - Laser-induced X-rays
KW - X-ray hazard
KW - X-ray emission
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639483
DO - https://doi.org/10.1007/s00339-025-08728-z
SN - 1432-0630
VL - 131
IS - 8
SP - 1
EP - 12
PB - Springer
CY - Berlin
AN - OPUS4-63948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kalbe, Ute
T1 - Elutionsverfahren in Forschung und regulatorischem Kontext
N2 - Elutionsverfahren sind ein Tool für Umweltverträglichkeitsprüfungen verschiedenster Materialien im Kontakt mit Wasser. Im früheren Fachbereich 4.3 Schadstofftransfer und Umwelttechnologien wurden dazu umfangreiche Kompetenzen vor allem im Zusammenhang mit mineralischen Reststoffen sowie vielfältigen Bauprodukten aufgebaut und experimentelle Erfahrungen gesammelt. Darüber hinaus wurde auch der Austrag von Partikeln betrachtet und die gleichzeitige Bewertung von Mikroplastik- und Schadstoffausträgen aus Kunsstofftrasen untersucht. Es sind aber auch weitere Anwendungen beispielsweise zur Prüfung der Beständigkeit von Materialien denkbar.
Im Workshop wurden Anwendungsbereiche von Elutionsverfahren diskutiert mit dem Ziel der besseren Vernetzung, der gemeinsamen Nutzung von Ressourcen und Identifikation von Synergien zwischen den Fachbereichen bzw. Aktivitätsfeldern.
T2 - Workshop - Bewertung der Freisetzung von (Schad)stoffen aus Materialien mit Elutionsverfahren
CY - Berlin, Germany
DA - 21.01.2025
KW - Elution
KW - Materialien
KW - Schadstoffe
PY - 2025
AN - OPUS4-65023
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Influence of Substrate Design on Properties and Residual Stresses in Hybrid AM/DED-Arc of High-Strength Steels
N2 - High-strength, fine-grained structural steels are increasingly used in modern steel construction to meet economic and environmental demands through lightweight design and reduced material usage. Additive manufacturing (AM), in particularly direct energy deposition with gas metal arc welding (DED-Arc), offers significant advantages in flex-ibility, production speed, and cost efficiency. In hybrid AM, conventionally manufac-tured parts are extended or modified using AM processes. Welding-induced residual stresses, especially in the transition area, pose challenges to structural integrity. This study investigates the influence of substrate design and thermal pretreatment on the residual stress state of hybrid AM components made from base material steel S690QL and a welding filler, a modified solid wire G79. Two substrate geometries (I- and T-substrate) are analysed, which are additively and conventionally manufactured, re-spectively. Results show that substrate geometry significantly affects local residual stresses, microstructure and hardness, particularly in the transition are. The findings contribute to a better understanding of the evolution of welding stresses in hybrid AM components to achieve reliable, crack-resistant and economic high-strength steel structures.
T2 - 4th International Conference on Advanced Joining Processes 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - DED-Arc
KW - Residual stress
KW - Hybrid additive manufacturing
PY - 2025
AN - OPUS4-65048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Influence of build-up height on residual stresses in additive repair and modification of multi-material composites using DED-Arc
N2 - The application of steels with a higher yield strength allows reductions in wall thickness, component weight and production costs. Hybrid additive manufacturing based on Gas Metal Arc Welding (GMAW) processes (DED-Arc) can be used to realise highly effi-cient component modifications and repairs on semi-finished products and additively manufactured structures. There are still a number of key issues preventing widespread implementation, particularly for SMEs. In addition to the manufacturing design, detailed information about assembly strategy and geometric adaptation of the component for modifications or repairs are missing. These include the welding-related stresses associ-ated with the microstructural influences caused by the additive manufacturing steps, particularly in the transition area of the substrate and filler material interface. The present research focuses the effect of component height on residual stress distribution. Defined specimens were welded fully automatically with a high-strength solid wire (yield strength > 790 MPa) especially adapted for DED-Arc on S690QL substrate.
T2 - IIW intermediate meeting for commission IX
CY - Trollhätten, Sweden
DA - 12.03.2025
KW - DED-Arc
KW - Residual stress
KW - Component height
PY - 2025
AN - OPUS4-65046
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Davenport, Rebecca
T1 - Regulations versus practice and the Divine Name: Ink analysis in medieval Torah scrolls
N2 - The medieval Rabbis had very strict rules for the construction of a Sefer Torah. The Divine Names should be written
• by a qualified scribe
• who is ritually pure
• in the presence of a minyan (10 adult Jewish men)
• in an appropriate frame of mind
• without being interrupted
However, when these scrolls were written it would have been impossible to verify any of this after the fact. While we do not currently have any way to determine how recently the scribes had bathed, or what they might have been thinking as they wrote, we can now know much more about the inscription of the Divine Name than these scribes ever would have guessed.
It is sometimes apparent from a visual inspection of the text that the Divine Name has been written in a second stage, from irregular letter kerning or a different ink colour. Using XRF, we have been able to discover more instances of a different ink used for the Name, and have shown that in some cases the secondary ink was also used to correct the main text, suggesting that the later writing was done by a master scribe who also proofread the entire scroll.
Using a Brucker M6 Jetstream, it has been possible to produce elemental “heat maps” of whole paragraphs or even large sections of a parchment sheet. Using such large samples of text, we can usefully compare the levels of copper and zinc used to write individual letters or words despite their relatively low concentration, which permits very fine differentiation of the inks used.
The techniques presented here would also be highly applicable to assessing ink degradation, as they are able to detect much smaller differences in ink composition than had previously been possible.
T2 - The International Iron Gall Ink Meeting 2025
CY - Lisboa, Portugal
DA - 07.05.2025
KW - XRF spectroscopy
KW - Torah scrolls
KW - Jewish studies
KW - XRF mapping
PY - 2025
AN - OPUS4-65036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, L.
A1 - Hsiao, I-L.
A1 - Ebisch, Maximilian
A1 - Vidmar, J.
A1 - Dreiack, N.
A1 - Böhmert, L.
A1 - Stock, V.
A1 - Braeuning, A.
A1 - Loeschner, K.
A1 - Laux, P.
A1 - Thünemann, Andreas
A1 - Lampen, A.
A1 - Sieg, H.
T1 - The presence of iron oxide nanoparticles in the food pigment E172
N2 - Iron oxides used as food colorants are listed in the European Union with the number E172. However, there are no specifications concerning the fraction of nanoparticles in these pigments.
Here, seven E172 products were thoroughly characterized. Samples of all colors were analyzed with a Broad spectrum of methods to assess their physico-chemical properties. Small-Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), zeta-potential, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), Asymmetric Flow Field-Flow Fractionation (AF4) and in vitro cell viability measurements were used.
Nanoparticles were detected in all E172 samples by TEM or SAXS measurements. Quantitative results from both methods were comparable. Five pigments were evaluated by TEM, of which four had a size median below 100 nm, while SAXS showed a size median below 100 nm for six evaluated pigments. Therefore, consumers May be exposed to iron oxide nanoparticles through the consumption of food pigments.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
PY - 2020
DO - https://doi.org/10.1016/j.foodchem.2020.127000
VL - 327
SP - 127000
PB - Elsevier Ltd.
AN - OPUS4-50810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Preparation of polypropylene and polyethylene nanoplastics in water
N2 - Considering the huge amount of plastics, that is produced and thrown away all over the world every day, an increasing part of the society became aware of microplastic and its possible impact on the environment. Polymer particles smaller than 1 µm are called nanoplastic. Due to their small size they form a special group within particulate waste. Their high specific surface makes it easier for them to penetrate tissue and pose potential harm. On the other hand, the size and the chemical structure make it difficult to detect and analyze nanoplastics in nature. Furthermore, the concentrations in environmental samples are very low. Therefore, there is a need for a well-characterized nanoplastic material, that serves as a reference for nanoplastic found in nature.
T2 - 101 years of Macromolecular Chemistry
CY - Online meeting
DA - 13.09.2021
KW - Nanoplastic
PY - 2021
AN - OPUS4-53773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thünemann, Andreas
T1 - Development of Reference Materials for Determination of Nanoplastics in Aqueous Media
N2 - A lack of harmonised terminology hinders accurate description of many nano-object properties. An overview on nanoscale reference materials for environmental , health and safety measurements has been provided by Stefaniak et al. Since then several nanoscale reference materials were produced as finely dispersed nanoparticles, including catalytic active silver nanoparticles and iron oxide nanocubes. Polymeric nanoparticles made of polypropylene (PP), polyethylene (PE) and poly(ethylene terephthalate) (PET) are ongoing reference materials projects. A first study on PP has shown that mechanical breakdown of macroscopic PP towards nano PP is possible. Hereby the nano PP is stabilized by a strongly negative zeta potential of – 44 mV. This provides a long-term stability of the nanoparticles at ambient conditions in cases of low ionic strength. Since this nano PP has no added colloidal stabilizers, we suggest this as a potential reference materials candidate for reliable determination PP nanoplastics. Moreover, the nano PP may function as a reference for the estimation of possible toxic effects of nanoplastics. Efforts in producing nano PP labeled with ultra-small gold nanoparticles are reported.
T2 - 22nd European Symposium on Polymer Spectroscopy
CY - Berlin, Germany
DA - 08.09.2024
KW - Nanoparticles
KW - Nanoplastics
PY - 2024
AN - OPUS4-61006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - del Rocío Silva-Calpa, Leydi
A1 - de Souza Bernardes, Andrelaine
A1 - de Avillez, Roberto Ribeiro
A1 - Smales, Glen J.
A1 - Camarena, Mariella Alzamora
A1 - Ramos Moreira, Carla
A1 - Zaitsev, Volodymyr
A1 - Archanjo, Braulio Soares
A1 - Letichevsky, Sonia
T1 - From support to shell: An innovative design of air-stable nano zero-valent iron–nickel catalysts via structural self-assembly
N2 - This work presents the design of air-stable core–shell zero-valent iron–nickel nanofilaments supported on silica and zeolite, developed to overcome the oxidation limitations of nano zero-valent iron in environmental catalysis. The nanofilaments feature ∼ 100 nm iron–nickel cores surrounded by ultrafine iron-rich threads embedded with aluminates and silicates, originating from partial support dissolution during synthesis. By varying the iron reduction time, three catalysts were prepared: one on silica reduced for 30 min, and two on zeolite reduced for 30 and 15 min. They were thoroughly characterized using nitrogen physisorption, X-ray diffraction, electron microscopy with elemental analysis, Mössbauer spectroscopy, and small-angle X-ray scattering. The zeolite-supported catalyst reduced for 15 min showed the highest activity for hexavalent chromium reduction (rate constant 8.054 min−1), attributed to a higher fraction of reactive iron–nickel phases formed under shorter reduction. Its tailored core–shell structure improves air stability and surface reactivity, highlighting its potential as a next-generation zero-valent iron nanocatalyst for aqueous remediation
KW - nanofilaments
KW - Core–shell nanostructures
KW - Air-stable nanomaterials
KW - Structure-controlled FeNi nanoparticles
KW - Hexavalent chromium reduction
KW - X-ray scattering
KW - MOUSE
PY - 2025
DO - https://doi.org/10.1016/j.mtcomm.2025.114142
SN - 2352-4928
VL - 49
SP - 1
EP - 15677
PB - Elsevier Ltd.
AN - OPUS4-65087
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berry, Charlotte A.
A1 - Reinart, Katre
A1 - Smales, Glen J.
A1 - Wilkinson, Holly N.
A1 - Hardman, Matthew J.
A1 - Marchesini, Sofia
A1 - Lee, William
A1 - Nery, Eveliny Tomás
A1 - Moghaddam, Zarrin
A1 - Hoxha, Agron
A1 - Felipe-Sotelo, Mónica
A1 - Gutierrez-Merino, Jorge
A1 - Carta, Daniela
T1 - Hierarchically porous copper and gallium loaded sol–gel phosphate glasses for enhancement of wound closure
N2 - In this work, we have developed hierarchically porous phosphate-based glasses (PPGs) as novel materials capable of promoting wound closure and simultaneously delivering antibacterial effects at the glass-biological tissue interface. PPGs are characterised by extended porosity, which enhances the controlled release of therapeutic ions, whilst facilitating cell infiltration and tissue growth. Two series of PPGs in the systems P2O5–CaO–Na2O–CuO and P2O5–CaO–Na2O–Ga2O3 with (CuO and Ga2O3 0, 1, 5 and 10 mol%) were manufactured using a supramolecular sol–gel synthesis strategy. Significant wound healing promotion (up to 97%) was demonstrated using a human ex vivo wound model. A statistically significant reduction of the bacterial strains Staphylococcus aureus and Escherichia coli was observed in both series of PPGs, particularly those containing copper. All PPGs exhibited good cytocompatibility on keratinocytes (HaCaTs), and analysis of PPG dissolution products over a 7-day period demonstrated controlled release of phosphate anions and Ca, Na, Cu, and Ga cations. These findings indicate that Cu- and Ga-loaded PPGs are promising materials for applications in soft tissue regeneration given their antibacterial capabilities, in vitro biocompatibility with keratinocytes and ex vivo wound healing properties at the biomaterial-human tissue interface.
KW - Porous glass
KW - Phosphates
KW - Wound healing materials
KW - Antibacterial
KW - X-ray scattering
KW - MOUSE
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650867
DO - https://doi.org/10.1039/d5tb01945a
SN - 2050-750X
VL - 13
IS - 48
SP - 15662
EP - 15677
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Barik, Birendra Kumar
A1 - Chaurasia, Prashant Kumar
A1 - Kumar, Vikram
A1 - Dak, Gauravkumar Roshanlal
A1 - Goecke, Sven-F.
A1 - De, Amitava
T1 - Probing smartphone-based photogrammetry for part profiling in wire arc directed energy deposition
N2 - Fast dynamic part profiling during wire arc directed energy deposition (DED-Arc) is required to maintain the dimensional consistency of the fabricated part as it is printed over several overlapped tracks and successive layers. The metrology methods such as laser scanning, though accurate, are costly and less flexible for monitoring of layer-wise deposition. Photogrammetry is an optical measurement technique to reconstruct a 3D geometry using a series of 2D images in different orientations to ensure complete coverage. We propose here a novel attempt for rapid dimensioning of the deposit geometry using smartphone-based photogrammetry for wire arc directed energy deposition (DED-Arc). The recorded images from multiple viewpoints are used for feature extraction and matching and triangulation-based 3D reconstruction of the deposit geometry using open-source software. The reconstructed deposit surface is compared with the original CAD geometry to compare the dimensional consistency of parts during the DED-Arc process. Experimental validation is performed on both simple (cuboid) and complex (hollow cylindrical) aluminum geometries, as well as a steel deposit against laser scanning data. The results demonstrate that the smartphone-based photogrammetry can capture the layer-wise geometry variations with the maximum height deviations well within 15% of the laser scan measurements. Although reconstruction and post-processing times are slightly longer in photogrammetry, the approach provides a flexible, accessible, and cost-effective alternative for part profile monitoring.
KW - DED-Arc
KW - Monitoring
KW - Dimensional consistency
KW - 3D reconstruction
KW - Part profiling
PY - 2025
DO - https://doi.org/10.1007/s40194-025-02273-2
SN - 0043-2288
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, H.
A1 - Krause, B.-C.
A1 - Kästner, Claudia
A1 - Böhmert, L.
A1 - Lichtenstein, D.
A1 - Tentschert, J.
A1 - Jungnickel, H.
A1 - Laux, P.
A1 - Braeuning, A.
A1 - Fessard, V.
A1 - Thünemann, Andreas
A1 - Luch, A.
A1 - Lampen, A.
T1 - Cellular Effects of In Vitro-Digested Aluminum Nanomaterials on Human Intestinal Cells
N2 - Aluminum (Al) can be taken up from food, packaging, or the environment and thus reaches the human gastrointestinal tract. Its toxic potential after oral uptake is still discussed. The fate of different solid and ionic Al species during the passage through the digestive tract is the focus of this research, as well as the cellular effects caused by these different Al species. The present study combines the physicochemical processing of three recently studied Al species (metallic Al0, mineral Al2O3, and soluble AlCl3) in artificial digestion fluids with in vitro cell systems for the human intestinal barrier. Inductively coupled plasma mass spectrometry (ICP-MS) and small-angle X-ray scattering (SAXS) methods were used to characterize the Al species in the artificial digestion fluids and in cell culture medium for proliferating and differentiated intestinal Caco-2 cells. Cytotoxicity testing and cellular impedance measurements were applied to address the effects of digested Al species on cell viability and cell proliferation. Microarray-based transcriptome analyses and quantitative real-time PCR were conducted to obtain a deeper insight into cellular mechanisms of action and generated indications for cellular oxidative stress and an influence on xenobiotic metabolism, connected with alterations in associated signaling pathways. These cellular responses, which were predominantly caused by formerly ionic Al species and only at very high concentrations, were not impacted by artificial digestion. A two-directional conversion of Al between ionic species and solid particles occurred throughout all segments of the gastrointestinal tract, as evidenced by the presence of nanoscaled particles. Nevertheless, this presence did not increase the toxicity of the respective Al species.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
PY - 2020
DO - https://doi.org/10.1021/acsanm.9b02354
VL - 3
IS - 3
SP - 2246
EP - 2256
PB - American Chemical Society
AN - OPUS4-50632
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thünemann, Andreas
T1 - Nanoplastics Aqueous Dispersions as Polymer Reference Materials for a Sustainable Future
N2 - The undesirable presence of micro and nanoplastics in our environment and in food is now common knowledge. However, it is unclear whether serious dangers and risks are posed by nanoplastics. A scientifically based reliable determination of the type and quantity of nanoplastics in complex matrices is of considerable importance for the future sustainable use of polymers. Here, reference materials help in the determination of nanoplastics. In particular, colloidally stable aqueous dispersions of nanoplastics appear suitable for this purpose. We report on the current status of the development of nanoplastics as reference materials. A detailed example of reference materials for characterizing nanoplastics is provided in the form of aqueous dispersion of polypropylene. The nanoplastics samples are colloidal stable for at least two years at ambient conditions. A low zeta potential of -35 mV at a neutral pH value provides stability. An overview of their colloidal properties in different environmental conditions is presented. Next, polyethylene nanoplastics will be compared to polypropylene nanoplastics. Nanoplastics consisting of poly(ethylene terephthalate) will be discussed and finally, we report on poly(L-lactic acid) as a typical and important representative of biodegradable polymers.
T2 - POLYMERS FOR A SUSTAINABLE FUTURE: Biennial Meeting of the GDCh-Division of Macromolecular Chemistry
CY - Dresden, Germany
DA - 16.09.2024
KW - Reference Material
PY - 2024
AN - OPUS4-61079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, L.
A1 - Saloga, Patrick E. J.
A1 - Stock, V.
A1 - Böhmert, L.
A1 - Braeuning, A.
A1 - Thünemann, Andreas
A1 - Lampen, A.
A1 - Sieg, H.
T1 - Environmental impact of ZnO nanoparticles evaluated by in vitro simulated digestion
N2 - ZnO nanoparticles are found in different food and consumer products, and their toxicological effects are still under investigation. It is therefore important to understand their behavior in the gastrointestinal tract. Here, we used an in vitro model to assess the physicochemical fate of ZnO nanoparticles during the digestive process in artificial saliva, stomach juice, and intestinal juice. Atomic absorption spectrometry and small-angle X-ray scattering were employed to investigate two ZnO nanomaterials, one intensively characterized reference material and soluble ZnCl2 in a broad range of concentrations between 25 and 1000 μg/mL in the intestinal fluid. Because food components may influence the behavior of nanomaterials in the gastrointestinal tract, starch, milk powder, and olive oil were used to mimic carbohydrates, protein, and fat, respectively. Additionally, ion release of all Zn species was assessed in cell culture media and compared to artificial intestinal juice to investigate relevance of typical cell culture conditions in ZnO nanotoxicology. ZnCl2 as well as the ZnO species were present as particles in artificial saliva but were solubilized completely in the acidic stomach juice. Interestingly, in the intestinal fluid a concentration-independent de novo formation of particles in the nanoscale range was shown. This was the case for all particles as well as for ZnCl2, regardless of the concentration used. Neither of the food components affected the behavior of any Zn species. On the contrary, all Zn species showed a Zn-concentration-dependent ion release in common cell culture medium. This questions the suitability of cell culture studies to investigate the effect of ZnO nanoparticles on intestinal cells. Our results show that Zn-containing nanoparticles reach the intestine. This underlines the importance of determining the influence of the test environment on nanoparticle fate.
KW - SAXS
KW - Digestion
KW - Zinc oxide
KW - Nanoparticles
PY - 2020
DO - https://doi.org/10.1021/acsanm.9b02236
VL - 3
IS - 1
SP - 724
EP - 733
AN - OPUS4-50288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gradt, Thomas
T1 - Materials for tribosystems in hydrogen technology
N2 - In this presentation tribological investigations on steels, polymers and coatings in gaseous and liquid hydrogen are shown. For steels the results of show that although martensitic steel may suffer from hydrogen embrittlement, application e.g. in roller bearings is possible. On the other hand, martensitic transformation of austenitic steels may cause problems in the application of these materials. Furthermore, the tribological performance of polymer composites with and without solid lubricant fillers in gaseous and liquid hydrogen was investigated. In particular, PEEK- and PTFE-matrix compounds showed low friction and sufficient low wear under these conditions. Among the solid lubricants, carbon-based materials are appropriate for hydrogen applications. Several variants of DLC and ta-C materials were tested. Beside the results for hydrogen, also a comparison with CH4-environment is shown.
T2 - ÖTG-Symposium 2021
CY - Online meeting
DA - 18.11.2021
KW - Hydrogen environment
KW - Liquid hydrogen
KW - Austenitic stainless steels
KW - Polymer composites
KW - DLC
PY - 2021
AN - OPUS4-53793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
A1 - Cano Murillo, Natalia
A1 - Hausberger, A.
T1 - Fretting behavior of elastomer materials in hydrogen
N2 - Safety and reliability are the major challenges to face for the development and acceptance of hydrogen technology. It is therefore crucial to study deeply material compatibility, in particular polymer materials that are directly in contact with hydrogen. This paper presents an experimental study on the fretting wear behavior of two types of cross-linked hydrogenated acrylonitrile butadiene rubbers against 316L steel ball in hydrogen environment. Furthermore, aging experiments were conducted for 7 days under static conditions in 100 MPa hydrogen. the influences of hydrogen pressure as well as the aging exposure on the fretting behavior are discussed by means of surface analyses along with the material properties.
T2 - 63. Tribologie-Fachtagung 2022
CY - Göttingen, Germany
DA - 26.09.2022
KW - Hydrogen
KW - Polymer materials
KW - Fretting
KW - Wear
PY - 2022
SN - 978-3-9817451-7-7
SP - 58/1
EP - 58/3
AN - OPUS4-56022
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
T1 - Sliding behaviour of polymer materials in hydrogen
N2 - This lecture deals with the sliding behaviour of polymer materials in hydrogen environment. After a short introduction of the hydrogen activities at BAM, the tribological performances of polymer materials in gaseous hydrogen are presented and compared with air and vacuum environment. The second part focusses on the influence of the counterface materials in hydrogen. Finally, the last section is dedicated to experiments liquid hydrogen.
T2 - Invited lecture, TRIBOS+ program at Lulea University of Technology
CY - Lulea, Sweden
DA - 30.06.2021
KW - Polymers
KW - Hydrogen
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-53708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
T1 - Friction and wear of polymer materials at cryogenic temperatures
N2 - This lecture deals with the friction and wear of polymeric materials at cryogenic temperatures. The first part is dedicated to the low temperature properties of polymers and cryogenic environment as well as an introduction to cryotribology and friction models. The second part presents some experimental results, focusing on the effect of polymer composition, cryogenic media and stick-slip behaviour.
T2 - Invited lecture, TRIBOS+ program at Lulea University of Technology
CY - Lulea, Sweden
DA - 29.06.2021
KW - Polymers
KW - Cryogenic temperature
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-53706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Harmonized tribological testing of polymers in hydrogen
N2 - To investigate typical polymer compounds and a potential alternative to be used in hydrogen compressors, tribological tests have been performed with several tribometers in hydrogen atmosphere. The compounds used were a commercially available PEEK matrix with 10 wt-% PTFE, graphite, and short carbon fibers each (supplied by company Polytron), a PPS matrix with 10 wt-% PTFE and graphite (supplied by company MOCOM) and an experimental PA12 matrix with PTFE, chemically coupled with an oleyl alcohol, as additive (supplied by the polymer research institute IPF). For all compounds a steel counter disc (type 316L / 1.4404) with a lapped surface was used in a cylinder on disc setup.
The focus of this work is to study the tribological performance of the polymers in hydrogen atmosphere. Additionally, tests were carried out with up to three different tribometers at two institutions. The challenge to compare and harmonize equipment, procedures, and methods is an important part of the study. This naturally includes the determination of the wear volumes of the polymeric cylinders. Furthermore, selected results of the wear and the resulting change in the contact geometry were compared by FEM simulations and an analytical model.
T2 - Colloquium H2Safety@BAM, Materials properties and compatibility
CY - Online meeting
DA - 14.05.2025
KW - Hydrogen
KW - Polymers
KW - Tribometer
KW - Wear
KW - Coefficient of Friction
KW - Interlaboratory comparison
KW - Comparability
KW - Harmonisation
KW - Standardisation
KW - Tribology
KW - Oil-coupled compounds
PY - 2025
AN - OPUS4-63103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iskhakov, Tagir
A1 - Breese, Philipp
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
T1 - Numerical and experimental analysis of temperature compensation for eddy current testing during laser powder bed fusion
N2 - The quality of parts produced via laser powder bed fusion (PBF-LB/M) can be affected by microstructural defects inherent to the process. In-situ monitoring technologies are crucial for ensuring consistent component quality. Eddy current testing (ECT) offers a viable method for real time monitoring during the PBF-LB/M build cycle. However, complex temperature fields arising during manufacturing significantly impact electrical conductivity, posing a challenge for ECT accuracy. Thus, precise temperature distribution prediction is essential for reliable flaw detection. This study develops a Finite Element (FE) model to predict the temperature field in multi-part build cycles. Scan vectors are grouped into clusters based on their timestamps, enabling the homogenization of thermal loads from multiple scan vectors. This approach allows for optimizing the trade-off between modeling accuracy and computational efficiency in a multi-part build. The study assesses the prediction accuracy required for ECT and investigates the appropriate level of homogenization needed to achieve it. Model predictions are validated through comparisons with thermography images and thermocouple measurements conducted during the manufacturing of 316L steel components.
KW - PBF-LB/M
KW - FEM
KW - Heat accumulation
KW - Eddy current testing
KW - 316L
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650165
DO - https://doi.org/10.1007/s40964-025-01429-2
SP - 1
EP - 20
PB - Springer Nature
AN - OPUS4-65016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Pérez-Padilla, Víctor
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Ratiometric detection of perfluoroalkyl carboxylic acids using dual fluorescent nanoparticles and a miniaturised microfluidic platform
N2 - The widespread contamination of soil and water with perfluoroalkyl substances (PFAS) has caused considerable societal and scientific concern. Legislative measures and an increased need for remediation require effective on-site analytical methods for PFAS management. Here we report on the development of a green-fluorescent guanidine-BODIPY indicator monomer incorporated into a molecularly imprinted polymer (MIP) for the selective detection of perfluorooctanoic acid (PFOA). Complexation of PFOA by the indicator, which is mediated by concerted protonation-induced ion pairing-assisted hydrogen bonding, significantly enhances fluorescence in polar organic solvents. The MIP forms as a thin layer on silica nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, which provides an orange emission signal as internal reference, resulting in low measurement uncertainties. Using a liquid-liquid extraction protocol, this assay enables the direct detection of PFOA in environmental water samples and achieves a detection limit of 0.11 µM. Integration into an opto-microfluidic system enables a compact and user-friendly system for detecting PFOA in less than 15 minutes.
KW - PFAS
KW - Molecular imprinting
KW - Microfluidics
KW - Fluorescence
KW - Onsite assay
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650270
DO - https://doi.org/10.1038/s41467-025-66872-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - PP and PE nanoplastics in water
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastics are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a "methodological gap" in the analytics of plastic particles with a diameter smaller than 1 μm. Submicron and nanoplastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastics found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics such as polypropylene (PP) and polyethylene (PE). We found an easy way to form nanoparticles consisting of PP and PE (nano-PP/PE). Herein, nano-PP/PE was formed via a top-down method where the polymer was dispersed to acetone and then transferred to water. No surfactant is needed to obtain a dispersion which is stable for more than 35 weeks.
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering. The chemical analysis of the nanoplastics was performed via Fourier Transform Infrared spectroscopy. Furthermore, electron microscopy was used to complement the results. To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
T2 - IUPAC-MACRO2020+
CY - Online meeting
DA - 17.05.2021
KW - Nanoplastic
PY - 2021
AN - OPUS4-53774
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Harmonized testing in hydrogen
N2 - In this study, the tribological performance of conventional and alternative polymer compounds for compressors was investigated in gaseous hydrogen using several tribometers. The compounds used were a commercial PEEK matrix with 10 wt.% each of PTFE, graphite, and short carbon fibres (Polytron), a PPS matrix with 10 wt.% each of PTFE and graphite (MOCOM), and an experimental PA12 matrix with PTFE, chamically coupled with an oleyl alcohol, as additive (supplied by the polymer research institute IPF). For all compounds a steel counter disc (type 316L / 1.4404) with a lapped surface finish was used in a cylinder-on-disc setup. Next to the tribological performance of the polymer compounds in hydrogen atmosphere, a strong focus of the work was to compare the results obtained with different tribometer setups. The tests were carried out with three different tribometers at two institutions. The challenge to compare and harmonise equipment, procedures, test and evaluation methods was an important part of the study. This includes the determination of the wear volumes of the polymeric cylinders with different wear analysis workflows. Furthermore, selected results of the wear and the resulting change in the contact geometry were compared with an FEM simulation and an analytical model.
T2 - 25th International Conference of Wear of Materials
CY - Sitges, Spain
DA - 14.04.2025
KW - Standardisation
KW - Harmonisation
KW - Hydrogen
KW - Polymers
KW - Wear
KW - Coefficient of Friction
KW - Interlaboratory comparison
KW - Tribometer
PY - 2025
AN - OPUS4-62992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Lei
A1 - Darvishi Kamachali, Reza
T1 - Incorporating elasticity into CALPHAD-informed density-based grain boundary phase diagrams reveals segregation transition in Al-Cu and Al-Cu-Mg alloys
N2 - The phase-like behavior of grain boundaries (GBs), recently evidenced in several materials, is opening up new possibilities in the design of alloy microstructures. In this context, GB phase diagrams are contributing to a predictive description of GB segregation and (interfacial) phase changes. The influence of chemo-mechanical solute-GB interactions on the GB phase diagram remains elusive so far. This is particularly important for multi-component alloys where the elastic interactions among solute atoms, of various sizes and bonding energies, can prevail, governing a complex co-segregation phenomenon. Recently, we developed a density-based model for GB thermodynamics that intrinsically accounts for GB elasticity in pure elements. In this work, we incorporate the homogeneous and heterogeneous elastic energies associated with the solutes into the density-based framework. We derive the multi-component homogeneous elastic energy by generalizing the continuum misfitting sphere model and extend it for GBs. The density-based free energy functional directly uses bulk CALPHAD thermodynamic data. The model is applied to binary and ternary Al alloys. We reveal that the elastic energy can profoundly affect the GB solubility and segregation behavior, leading to Cu segregation in otherwise Cu-depleted Al GBs. Consequently, GB segregation transition, i.e., a jump in the GB segregation as a function of alloy composition, is revealed in Al-Cu and Al-Cu-Mg alloy systems with implications for subsequent GB precipitation in these alloys. CALPHAD-informed elasticity-incorporated GB phase diagrams enable addressing a broader range of GB phenomena in engineering multi-component alloys.
KW - Grain boundary thermodynamics
KW - Density-based model
KW - Al alloys
KW - Grain boundary phase diagram
KW - CALPHAD
KW - Elastic energy
PY - 2021
DO - https://doi.org/10.1016/j.commatsci.2021.110717
VL - 199
SP - 110717
PB - Elsevier B.V.
AN - OPUS4-53058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
T1 - On the cubic slip effect and creep anisotropy modeling of single crystal superalloys at intermediate temperatures (IT)
N2 - Low-Temperature High Stress (LTHS) creep plays a crucial role in Ni-base Superalloys, particularly affecting components like blades near the root. Below 850°C, the precipitate microstructure remains stable, characterized by periodically arranged ’ cubic precipitates surrounded by the -matrix. In these conditions, macroscopic traces of cubic slip have been observed in <111> oriented tensile specimens, whereas their microscopic origin has been a topic of debate. Furthermore, in LTHS conditions, Superlattice Intrinsic, Extrinsic Stacking Faults (SISF/SESF), or micro-twins are also frequently reported in crept specimens. Usually, these mechanisms are investigated separately, so that a unified picture and a detailed understanding of these mechanisms and their activation conditions have only recently emerged in the literature, despite the intensive investigations of the last decades.
The objective of this work is to develop a dislocation-based constitutive law that includes these recent developments. In particular, the pseudo-cubic slip mechanism is considered as resulting from the lack of hardening in <111> oriented tensile specimens and is represented by a novel estimate of the back-stresses based on the spectral decomposition of a tensorial representation of the back-stress. An additional novelty is that SISF- and SESF-related slip systems are accounted for as distinct slip systems with corresponding dislocation densities. The model has been implemented as a user-defined constitutive law for commercial Finite Element codes and identified as well as validated with data from the literature obtained with <001>, <011> and <111> oriented crystals tested in tension and compression creep.
T2 - International Conference on Material Modelling (8)
CY - London, GB
DA - 15.07.2024
KW - Creep
KW - Superalloy
KW - Crystal plasticity
KW - Single crystal
PY - 2024
AN - OPUS4-60744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
T1 - A model for grain boundary thermodynamics
N2 - Systematic microstructure design requires reliable thermodynamic descriptions of each and all microstructure elements. While such descriptions are well established for most bulk phases, thermodynamic assessment of microstructure defects is challenging because of their individualistic nature. In this paper, a model is devised for assessing grain boundary thermodynamics based on available bulk thermodynamic data. We propose a continuous relative atomic density field and its spatial gradients to describe the grain boundary region with reference to the homogeneous bulk and derive the grain boundary Gibbs free energy functional. The grain boundary segregation isotherm and phase diagram are computed for a regular binary solid solution, and qualitatively benchmarked for the Pt–Au system. The relationships between the grain boundary's atomic density, excess free volume, and misorientation angle are discussed. Combining the current density-based model with available bulk thermodynamic databases enables constructing databases, phase diagrams, and segregation isotherms for grain boundaries, opening possibilities for studying and designing heterogeneous microstructures.
KW - Phase Diagram
KW - Thermodynamics
KW - Grain boundary
PY - 2020
VL - 10
IS - 45
SP - 26728
EP - 26741
AN - OPUS4-51268
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schob, Daniela
T1 - ICY PRECISION - Material Testing for Cryogenic Hydrogen Applications
N2 - For cryogenic hydrogen storage in aerospace applications, reliable mechanical characterisation at 20 K is indispensable. While testing at 77 K (liquid nitrogen) and 4 K (liquid helium) is well established, stand-ardised procedures in the temperature range relevant for liquid hydrogen are still lacking. This gap rep-resents a key challenge for materials development. A critical aspect is the accurate measurement of strain under extreme conditions: clip-on extensometers provide global yet contact-based data, whereas digital image correlation (DIC) enables non-contact, full-field strain acquisition. Using glass cryostats, DIC has been successfully applied at 4 K and 77 K, allowing the capture of high-resolution deformation fields. As a next step, a newly developed test rig is introduced, based on a helium circulation system. It enables not only isothermal testing down to 20 K but also programmable temperature profiles between 10 and 350 K, providing an essential opportunity to reproduce thermomechanical loading conditions close to service environments. An integrated observation window further allows direct measurement of the true stress–strain response. This opens the prospect of assessing materials under realistic cryogenic conditions in a reproducible and comparable manner.
T2 - DGM - 43. Werkstoffprüfung
CY - Dresden, Germany
DA - 27.11.2025
KW - Cryogenic material testing
KW - Digital image correlation
KW - Quasi-static
KW - Low cycle fatigue
PY - 2025
AN - OPUS4-65250
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
T1 - Untersuchung des Kriechverhaltens einer Nickelbasis-Superlegierung bei ultrahohen homologen Temperaturen und Anwendung auf das heiß-isostatische Pressen (HIP)
N2 - Mit Hilfe des HIP-Verfahrens („Hot Isostatic Pressing“) werden Poren in der einkristallinen Nickel-Basis Superlegierung CMSX-4 kontinuierlich geschrumpft und dadurch die nach der Erstarrung und der Wärmebehandlung vorhandene Porosität stark reduziert. In diesem Beitrag werden experimentelle und numerische Untersuchungen zu den Mechanismen der Porenschrumpfung zusammengefasst. Es zeigt sich, dass das Verformungsverhalten während Kriechversuchen bei der HIP-Temperatur durch Versetzungsgleitung auf oktaedrischen Ebenen dominiert wird.
Dagegen zeigen Messungen der Porositätsabnahme und Simulationen des Porenschließens, dass die Kinetik der Porenschrumpfung durch das Phänomen der Leerstellendiffusion zwischen Poren und Kleinwinkelkorngrenzen („Low Angle Boundary“, LAB) bestimmt wird. Im Gegensatz führt die klassische Kristallviskoplastizität zu einer systematischen Überschätzung dieser Kinetik. Der scheinbare Widerspruch lässt sich auflösen, wenn man bedenkt, dass auf der Skala der Poren Versetzungsquellen nicht gleichmäßig verteilt sind, wie in der konventionellen Kristallplastizität implizit angenommen wird. Stattdessen wird in einem weiterführenden Modell davon ausgegangen, das Kleinwinkelkorngrenzen (LABs) als Versetzungsquellen fungieren, während die Scherspannungen sehr stark in der Nähe der Poren lokalisiert sind, was die Emission von Versetzungen deutlich reduziert.
T2 - Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe
CY - Online meeting
DA - 27.11.2020
KW - HIP
KW - Superlegierung
KW - Kriechen
PY - 2020
AN - OPUS4-51795
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jacobson, David
A1 - Darvishi Kamachali, Reza
A1 - Thompson, Gregory
T1 - Coupling density phase field models with atomistic potentials
N2 - A density-based phase field model is developed where the free energy functional is explicitly linked with molecular dynamics and is referred to as the Molecular Phase Field Method (MoPF). MoPF simulations involve expressing interatomic potentials in terms of density to form a density based free energy functional. Inputs to this functional are taken from atomistics such that the phase field density profile matches the corresponding density profile from atomistic simulations. We analyze our results by comparing the MoPF calculated excess interfacial energies with excess interfacial energies calculated using molecular dynamics associated with several nickel grain boundaries. Additionally, a comparison is made between our results and the interfacial energies of a \Sigma7 boundary across a variety of FCC systems simulated using density functional theory. The MoPF method is able to successfully predict grain boundary free energy trends between grain boundary and material types offering an atomistically informed mesoscale formulation for studying grain boundary physics.
KW - Density-based Phase-Field Modelling
KW - Atomistic Simulation
KW - Grain Boundary
PY - 2024
DO - https://doi.org/10.1016/j.commatsci.2023.112763
VL - 233
SP - 1
EP - 6
PB - Elsevier
AN - OPUS4-59360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Mechanical behaviour of AM metals: Creep of LPBF 316L and low-cycle-fatigue of LMD Ti-6Al-4V
N2 - Additively manufactured metallic materials have already started to find application in safety-relevant components. However, this has only happened for certain materials and specific applications and loading conditions, since there is still an extensive lack of knowledge as well as of historical data regarding their mechanical behaviour. This contribution aims to address this lack of understanding and historical data concerning the creep behaviour of the austenitic stainless steel 316L manufactured by Laser-Powder-Bed-Fusion (L-PBF) and the low-cycle-fatigue behaviour of the titanium alloy Ti-6Al-4V manufactured by Laser-Metal-Deposition (LMD). Furthermore, it aims to assess their mechanical behaviour against their conventional counterparts. With that in mind, specimens from conventional and additive materials are tested and their mechanical behaviour analysed based on characteristic curves. To understand the damage behaviours the materials are characterized by destructive and non-destructive techniques before and after failure.
T2 - 1st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online Meeting
DA - 10.12.2020
KW - Ti-6Al-4V
KW - 316L
KW - Additive manufacturing
KW - Creep behaviour
KW - Low-cycle-fatigue behaviour
PY - 2020
AN - OPUS4-51879
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezhov, Alexander
A1 - Ben Shir, I.
A1 - Schmidt, A.
A1 - Kovler, K.
A1 - Diesendruck, Ch. E.
T1 - Retardation mechanism of cement hydration by a comb polyphosphate superplasticizer
N2 - The retardation mechanism of cement hydration as imparted by the addition of polyphosphate comb superplasticizer to model cement containing C3S, C3A and calcium sulfate hemihydrate is studied using XRD, ss NMR and calorimetry. Our findings show the retardation effect caused by the direct addition of polyphosphate comb superplasticizer differs significantly to that of conventional polycarboxylate superplasticizers. Conversely to polycarboxylates, polyphosphates, at a low dosage, inhibits the silicate reaction without affecting the aluminate reaction and formation of ettringite. Yet, at high doses, both reactions are hampered, and the induction period extended, followed by accelerated aluminate and silicate reactions.
KW - Superplasticizer
KW - Polyphosphate
KW - Retardation
KW - Cement hydration
PY - 2022
DO - https://doi.org/10.1016/j.conbuildmat.2022.128698
SN - 0950-0618
VL - 352
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-58246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapiro, I.
A1 - Mezhov, Alexander
A1 - Kovler, K.
T1 - Performance of corrosion inhibitors in reinforced concrete elements under electrical voltage
N2 - The current paper develops a novel accelerated corrosion test method based on Faraday’s law to investigate the performance of different inhibitors in reinforced concrete elements under electrical voltage. Using the proposed method two commercially available and three lab-made inhibitors were tested. Lab-made inhibitors based on potassium fluorosilicate and amine carboxylate showed the best performance over others. Furthermore, it is found that under an electrical potential environment beyond 3.6 V, the higher the concrete strength, the more efficient is the corrosion inhibition. Based on experimental results, a novel model describing the corrosion evolution in reinforced concrete was proposed.
KW - Steel corrosion
KW - Reinforced concrete
KW - Accelerated test
KW - Corrosion inhibitor
KW - Stray current
PY - 2022
DO - https://doi.org/10.1016/j.conbuildmat.2022.127656
SN - 0950-0618
VL - 342
IS - 342
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-58249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - The Impact of Ultrasonic-Assisted Milling and Alloying Elements on the Surface Integrity of Additively Manufactured Iron Aluminides
N2 - The increasing focus on energy and resource efficiency has driven the implementation of additive manufacturing (AM) of high-performance materials, particularly in lightweight constructions with optimization of material efficiency. Iron aluminides (FeAl) hold great potential due to their low density, excellent corrosion and wear resistance, high-temperature stability, and vast availability. However, the inherent heterogeneity and anisotropy of FeAl-AM structures pose significant challenges, especially regarding hardness and brittleness. These material characteristics complicate the mostly necessary post-processing via mechanical finish machining, often resulting in elevated cutting forces, accelerated tool wear, and suboptimal surface integrity. Ultrasonic-assisted milling (USAM), a hybrid machining process, offers significant advantages over conventional milling (CM), including the reduction of cutting forces and tool wear. Notably, USAM has been demonstrated to decrease surface defect density and mitigate tensile residual stresses, while potentially inducing beneficial compressive residual stresses within the depth profile of the component’s surface. These effects can significantly enhance crack propagation resistance, improve corrosion behavior, and extend the fatigue life of components in safety-relevant applications. The present study investigates the effects of additional alloying elements such as molybdenum, nickel, titanium and Vanadium in FeAl as well as milling parameters, including cutting speed vc and feed rate fz, on the surface integrity with special regard to residual stress formations.
T2 - 4th International Conference on Advanced Joining Processes
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Additive Manufacturing
KW - Wear Protection
KW - Ultrasonic-assisted Milling
KW - Iron-aluminides
KW - MPEA
KW - Surface Integrity
KW - Residual Stresses
PY - 2025
AN - OPUS4-65235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abdelkhalik, A.
A1 - Askar, Enis
A1 - Markus, D.
A1 - Stolz, T.
A1 - Brandes, E.
A1 - Zakel, S.
T1 - Explosion regions of 1,3-dioxolane/nitrous oxide and 1,3-dioxolane/air with different inert gases - Experimental data and numerical modelling
N2 - In this study, experimental determination and modelling investigations for the explosion regions of 1,3-dioxolane/inert gas/N2O and 1,3-dioxolane/inert gas/air mixtures were carried out and compared. The experimental measurements were carried out at 338 K and atmospheric pressure according to EN1839 method T using the inert gases N2, CO2, He and Ar. The results showed that the ratio of the lower explosion limit in N2O (LELN2O) to the lower explosion limit in air (LELair) is 0.52 and the ratio of the maximum oxygen content in air (MOCair) to the limiting oxidizer fraction in nitrous oxide (LOFN2O) is 0.36 ± 0.02 independent of the inert gas. When comparing the inert gas amount at the apex based on the pure oxidizing component, which is O2 in case of air, N2O-containing mixtures need less inert gas to reach the limiting oxidizer quantity whereas the efficiency of inert gases is in the same order. The coefficients of nitrogen equivalency however were found to differ to some extent. The explosion regions of 1,3-dioxolane/inert gas/oxidizer mixtures were modelled using the calculated adiabatic flame temperature profile (CAFTP) method as well as corrected adiabatic flame temperatures. The results indicate good agreement with experimental data for CO2, N2 and Ar- containing mixtures. The noticeable deviations that occur when He is the inert gas are due to the lacking transport data of that mixture.
KW - Explosion limits
KW - Flammability
KW - CAFTP
KW - Adiabatic Flame Temperatures
PY - 2021
DO - https://doi.org/10.1016/j.jlp.2021.104496
SN - 0950-4230
VL - 71
SP - 4496
PB - Elsevier Ltd
AN - OPUS4-52849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Liquid Metal Embrittlement in High-Strength Steels
N2 - One contribution of materials science to energy efficiency is the continuous development of novel high-performance structural materials that push the strength-ductility envelope. A prominent example are modern advanced high-strength steels (AHSSs), which have enabled considerable weight reductions in the automotive sector, thereby enabling greenhouse emission reductions. To protect such advanced alloys from property degradation via corrosion, zinc (Zn) coatings are often applied through galvanization. Whilst protective, a Zn-coating comes with problems – the AHSS substrate becomes susceptible for liquid-metal embrittlement (LME) than can be the origin of significant mechanical property degradation when liquified Zn infiltrates into the steel substrate. Being for from understood, we focus here on non-cracked environments to capture the early stages of LME. This approach revealed the nucleation and growth of nano-scale intermetallic phases inside uncracked GBs (Materials Today Advances 13, 100196, 2022), highlighting the complex multi-phase microstructure developing before cracking occurs. To shed further light on the early stages of LME in AHSSs, we also consider the microstructural evolution of interrupted welds. We discuss our findings in the context of the time-resolved substructure evolution right beneath the interface between the AHSS and the Zn-based coating and track how Zn progressively infiltrates the substrate along phase and grain boundaries. The experimental results are further corroborated with thermodynamic simulations.
T2 - ASATM
CY - Singapore
DA - 10.01.2023
KW - Liquid-metal embrittlement
KW - Steels
KW - Grain boundaries
KW - Micro-cracking
PY - 2023
AN - OPUS4-60647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reichel, Levin
T1 - Reparaturschweißen in der schweißtechnischen Montage: Moderne Schweißverfahren für hochfeste Offshore-Stähle
N2 - Der Ausbau der Offshore-Windenergie mit Anlagenleistungen von über 10 MW er-fordert zunehmend den Einsatz hochfester Stähle mit Streckgrenzen ab 460 MPa bei Wanddicken von bis zu 150 mm. Inakzeptable Defekte, die während bzw. nach der schweißtechnischen Montage solcher dickwandigen Verbindungen im Nahtbereich detektiert werden, können wirtschaftlich durch lokales Ausfugen und anschließendes Schweißen noch in der Fertigung repariert werden. Insbesondere bei hochfesten Baustählen stellt dies hohe Anforderungen an die schweißtechnische Fertigung, da bislang keine standardisierten Reparaturkonzepte oder normativen Vorgaben existie-ren. Praxisnahe Empfehlungen sind hier vor allem für kleine und mittlere Unterneh-men (KMU) notwendig, damit diese Reparaturschweißungen sicher und wirtschaft-lich durchführen können.
Die laufende Untersuchung (FOSTA P1629/IGF 01IF22746N) legt daher den Schwerpunkt auf die Optimierung der Reparaturverfahren mit dem Ziel, schweißbe-dingte Beanspruchungen zu reduzieren, weil diese häufig zu erneuten Bildung Fehl-stellen führen. Hierfür werden hochfeste, dickwandige Verbindungen aus Offshore-Stahlgüten im Streckgrenzenbereich von 355 MPa bis 460 MPa untersucht. Die ex-perimentellen Analysen berücksichtigen dabei die komplexen Wechselwirkungen zwischen werkstoff- und prozess- sowie konstruktionsbedingten Einflüssen auf den Beanspruchungszustand nach dem Schweißzyklus (Verbindungsschweißen, Ausfu-gen, Reparaturschweißen). Diese Faktoren, wie z. B. die Steifigkeitsverhältnisse der Schweißnaht, sind von entscheidender Bedeutung für die resultierenden Eigenspan-nungen, die sich infolge der schweißtechnischen Reparatur ausbildet. Um die Bau-teilsicherheit und Leistungsfähigkeit zu gewährleisten, sind insbesondere risskriti-sche, mehrachsige Eigenspannungszustände zu vermeiden. So lassen sich moderne Hochleistungs-MAG-Schweißprozesse mit hierfür optimierten, schmaleren Fugen-geometrien in bauteilbezogenen Schweißversuchen auf Großprüfanlagen untersu-chen, um hierfür angepasste Prozess- und Wärmeführungsparameter zu identifizie-ren und angepasste Reparaturkonzepte abzuleiten. Ziel ist es, Handlungsempfehlun-gen für Richtlinien und Normen zu erarbeiten, die das Potenzial hochfester Stähle voll ausschöpfen und die Anwendbarkeit im Offshore-Stahlbau, insbesondere für KMU, substanziell stärken. Auf diese Weise leistet das Projekt einen entscheiden-den Beitrag zur erfolgreichen Umsetzung der Energiewende in Deutschland.
T2 - Forschungsseminar OVGU-Magdeburg
CY - Magdeburg, Germany
DA - 18.06.2025
KW - Moderne Schweißprozesse
KW - Offshore
KW - Reparaturschweißen
KW - Thermisches Ausfugen
KW - Eigenspannungen
KW - Gefügedegradation
PY - 2025
AN - OPUS4-65238
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Ultraschallunterstütztes Fräsen innovativer metallischer Werkstoffe zur Optimierung von Oberflächenintegrität und Werkzeugverschleiß Neueste Erkenntnisse und Perspektiven im Kontext der Komponentensicherheit
N2 - Der Vortrag behandelt ultraschallunterstütztes Fräsen als innovative Technologie zur Bearbeitung schwer zerspanbarer metallischer Werkstoffe und deren Einfluss auf Oberflächenintegrität, Werkzeugverschleiß und Komponentensicherheit. Ausgangspunkt ist die Herausforderung durch hohe Festigkeit, heterogene Gefüge und Eigenspannungen bei konventioneller und additiver Fertigung (z. B. Ni-, Co-Legierungen, Eisen-Aluminide). Diese Faktoren führen zu erhöhten Prozesskräften, Werkzeugverschleiß und nachteiligen Oberflächeneigenschaften.
Ultraschallunterstützung reduziert Zerspankräfte, stabilisiert Prozesse bei AM-Bauteilen und verbessert die Oberflächengüte durch Einbringung von Druckeigenspannungen. Untersuchungen zeigen: Optimale Amplituden (ca. 4 µm) minimieren Eigenspannungen und Defekte, erhöhen die Ermüdungsfestigkeit und verlängern die Werkzeugstandzeit. Bei Eisen-Aluminiden und DED-Arc-gefertigten Bauteilen konnten deutliche Verbesserungen in Rauheit, Kraftverlauf und Verschleiß erzielt werden. Für Co-/Ni-Legierungen wurde zusätzlich die Wirksamkeit durch Legierungsmodifikation nachgewiesen.
Perspektivisch bietet die Technologie Potenzial für Lebensdauersteigerung hochfester Bauteile, Integration von Oberflächenverfestigung in den Fräsprozess und Reduktion von Nachbearbeitungsschritten. Geplante Projekte adressieren Hochentropielegierungen, Mehrkomponentenwerkstoffe und hybride Fertigungsstrategien. Insgesamt zeigt sich, dass US-Fräsen eine Schlüsselrolle für ressourceneffiziente, sichere und leistungsfähige Komponenten in Leichtbau und Hochtemperaturanwendungen einnehmen kann.
T2 - 4. Wissenschaftliches Forum zur ULTRASONIC-Bearbeitung
CY - Jena, Germany
DA - 12.11.2025
KW - Ultraschallunterstütztes Fräsen
KW - Oberflächenintegrität
KW - Werkzeugverschleiß
KW - Zerspankräfte
KW - Additive Fertigung (DED-Arc, AM)
KW - Eisen-Aluminid
KW - Co-/Ni-Legierungen
KW - Ermüdungsfestigkeit
KW - Eigenspannungen
KW - Lebensdauersteigerung
KW - Hybridfertigung
KW - Hochentropielegierungen (MPEA)
PY - 2025
AN - OPUS4-65240
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Begrüßung und Vorstellung der BAMund des Fachbereichs 9.2 - Zentrale Forschungswerkstatt
N2 - Die Zentralwerkstatt der BAM übernimmt die Fertigung und Konstruktion komplexer Prüf- und Versuchseinrichtungen und adressiert zugleich zentrale Forschungsthemen zur Werkstoff- und Komponentensicherheit. Dazu gehören die Entwicklung innovativer Fertigungstechnologien, ressourceneffiziente Verarbeitungskonzepte für hochfeste und additive Komponenten sowie die Untersuchung von Fertigungseinflüssen auf Oberflächenintegrität und Werkstoffdegradation. Ein besonderer Fokus liegt auf der H₂-Sicherheit, insbesondere der Fertigung und Prüfung von Hohlzugproben für Wasserstoff-Pipelines. Ergänzend werden Automatisierungslösungen, digitale Methoden und moderne Spanntechnik zur Effizienzsteigerung eingesetzt. Die Arbeiten sind eng mit den BAM-Kompetenzzentren AM@BAM, H2Safety@BAM und WIND@BAM verzahnt und leisten einen Beitrag zur Energiewende sowie zur Normung und zum Technologietransfer.
T2 - 37. Stammtisch Metall des "Der Mittelstand BVMW e.V. "
CY - Berlin, Germany
DA - 17.09.2025
KW - Werkstoffsicherheit
KW - H₂-Sicherheit
KW - Additive Fertigung
KW - Ressourceneffizienz
KW - Automatisierung in der Fertigung
KW - Prüftechnikentwicklung
KW - Normung und Technologietransfer
KW - Oberflächenintegrität
PY - 2025
AN - OPUS4-65245
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - HGF-AK "Bau wissenschaftlicher Geräte" - Neues aus der BAM / Fachbereich 9.2
N2 - In dieser Präsentation werden die neuesten Herausforderungen und der Stand des Fachbereiches 9.2 für die Mitarbeit im AK des HGF "Bau wissenschaftlicher Geräte" dargestellt. Hierfür werden Neuigkeiten aus dem Bereich Materialprüfung in der BAM präsentiert und mit den Arbeiten der Zentralwerkstatt, die hierfür notwendig sind, in Zusammenhang gebracht.
T2 - 20. Jahrestagung des Helmholtz-Arbeitskreis "Bau wissenschaftlicher Geräte"
CY - Jülich, Germany
DA - 07.05.2025
KW - Fertigungskompetenz
KW - Fertigungsverfahren
PY - 2025
AN - OPUS4-65243
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reichel, Levin
T1 - Optimising repair welding: narrower groove design for modern welding processes on high-strength offshore steels
N2 - The ongoing energy transition in Germany requires large offshore wind turbines with outputs over 10 MW and suitable deep-water subsea structures. Large towers made of high-strength steel with a yield strength of up to 500 MPa are needed to use the mate-rial more efficiently, enabling thinner wall sections without compromising structural integrity. This places high demands on manufacturers, especially regarding welding high-strength offshore steels. Weld defects detected through non-destructive testing (NDT) must be repaired by gouging and rewelding during fabrication. For thick plate joints, there is a notable lack of research, repair strategies, and guidance in standards and guidelines. Safe and cost-effective repairs are urgently necessary to support manufacturers, particularly SMEs. This study focuses on high-strength thick plate joints made of offshore grades with a yield strength of 355 to 460 MPa, repaired us-ing optimised narrow gouging grooves and controlled high-performance GMAW pro-cesses. Experimental analyses examine the complex interaction between the welding process, material properties, and design influences on the formation of weld-induced residual stresses in high-strength fine-grain structural steels. To ensure the safety and performance of components, it is essential to prevent repair welding-related material degradation and the development of crack-critical residual tensile stresses.
In this investigation, gouging was carried out using milling to ensure reproducibility. The restraint intensity of the groove significantly increases with a shorter groove length and a thicker substrate. The relaxation caused by the gouging process was ana-lysed using X-ray diffraction (XRD) to examine the initial conditions for the subse-quent repair welding. The residual stresses induced by the repair welding were ana-lysed, and different groove configurations have been compared. With shorter groove lengths and wider opening angles, the residual stresses after the repair weld increase markedly for this analysed offshore steel. The lowest residual stresses can be achieved by increasing the groove length and reducing the opening angle for a repair weld with a modern, controlled welding process. Adapting the repair process and boundary conditions allows for the full utilisation of the material's potential. This makes a valuable contribution to the energy transition in Germany, especially for SMEs in the steel processing industry.
T2 - Forschungsseminar OVGU-Magdeburg
CY - Magdeburg, Germany
DA - 10.12.2025
KW - Repair welding
KW - Narrow groove
KW - Controlled arc
KW - Residual stress
KW - High-strength offshore steel
PY - 2025
AN - OPUS4-65239
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marschall, Niklas
T1 - Spinodal Decomposition in FeMnNiCoCu: Alloying effects
N2 - Spinodal decomposition in multi-component alloys remains insufficiently understood, particularly when multiple driving forces govern phase evolution. Chemical thermodynamics provides reliable predictions of spinodal instabilities, but elastic energy contributions can significantly alter the boundaries of phase stability. In this work, we establish a framework to analyze phase stability in high-entropy alloys by combining Hessian-based spinodal analysis with convex hull constructions that capture miscibility gaps. This approach allows us to disentangle the roles of chemical, elastic, and kinetic factors in early-stage decomposition. Our results highlight how elastic contributions can extend the effective spinodal region beyond chemically predicted boundaries, thereby influencing microstructural pathways. This combined stability analysis offers new insights into the mechanisms governing decomposition and advancing the theoretical understanding of phase evolution in high-entropy alloys.
T2 - FEMS EUROMAT 2025
CY - Granada, Spain
DA - 14.09.2025
KW - High-entropy alloy
KW - Elasticity
KW - Phase stability
KW - Hessian
KW - Convex hull
PY - 2025
AN - OPUS4-64263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Fedelich, Bernard
ED - Cailletaud, G.
ED - Cormier, J.
ED - Eggeler, G.
ED - Maurel, V.
ED - Nazé, L.
T1 - Crystal plasticity models: dislocation based
N2 - The large number of TEM investigations and the regular microstructure
of single-crystal nickel-base superalloys has boosted the development of a number of physically motivated constitutive laws. In contrast to the more phenomenological models discussed in the next chapter, these models use dislocation densities as internal variables. Obvious advantages are that the computed densities can be compared to TEM observations and the Deformation mechanisms can be easier translated into mathematical equations.
KW - Nickel-base superalloys
KW - Creep
KW - Plasticity
PY - 2022
SN - 978-0-12-819357-0
SP - 401
EP - 427
PB - Elsevier Inc.
ET - 1
AN - OPUS4-53436
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Falkenberg, Rainer
T1 - Modelling of hydrogen-induced ductility loss in titanium-based hydrogen storage
N2 - One promising solution for decarbonisation is the use of hydrogen as energy carrier. Besides its exceptional advantages like high calorific value, better safety and non-existent harmful emissions, one major challenge is still hydrogen embrittlement of Ttitanium alloys used as a hydrogen storage. In this work, a method is presented that can numerically model and determine a threshold concentration of hydrogen in solid solution responsible for a sudden ductile-to-brittle transition. The origin of this sudden loss of ductility lies in the segregation kinetics thermodynamics that is modelled together with an elastoplastic fracture mechanics model. Starting from experimental fracture mechanics test data, a meaningful coupling mechanism was found for the fracture mechanics cohesive zone model in the form of a segregation-modified cohesive energy that triggers an acceleration of crack extension above defined concentration values. It can be demonstrated that above a threshold of only few atomic percent hydrogen in the solid solution, the segregated hydrogen concentration exceeds 20 at.%. The current results present a mechanism that enables the modelling of the sudden ductility loss triggered by a segregation-affected crack energy expression in titanium alloys exposed to hydrogen. This method is not only applicable to other various materials but can also be a substantial benefit for the safety assessment of hydrogen storage devices.
T2 - 5th EMMC International Workshop 2025
CY - Vienna, Austria
DA - 08.04.2025
KW - Segregation Transition
KW - Hydrogen Embrittlement
KW - Titanium Alloys
KW - Crack Propagation
KW - Ductile-to-Brittle Transition
PY - 2025
AN - OPUS4-63177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blank, Robin
A1 - Nitschke, Heike
A1 - Saliwan Neumann, Romeo
A1 - Kranzmann, Axel
T1 - Materialographic Preparation of Salt
N2 - Molten salt containing systems gain in importance for sustainable energy use and production. For research and development, interactions of molten salts with potential container materials are of major interest. This article introduces preparation procedures to display an intact metal and salt microstructure and their interface using light optical microscopy and scanning electron microscopy. The exemplary material combination is the ternary salt mixture NaCl-KCl-MgCl2 and the low alloyed steel 1.4901 (T92) with a maximum service temperature of 550 °C. These are potential elements/materials for use in latent heat thermal energy storages.
KW - Molten salt
KW - Corrosion
KW - Steel
KW - Aging
KW - Dry preparation
PY - 2021
DO - https://doi.org/10.1515/pm-2022-0058
VL - 59
IS - 10
SP - 628
EP - 640
PB - De Gruyter
AN - OPUS4-56048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Lei
A1 - Darvishi Kamachali, Reza
T1 - CALPHAD integrated grain boundary co-segregation design: Towards safe high-entropy alloys
N2 - Along with the desire for developing novel multi-principal element alloys, also known as high-entropy alloys, the concern about their safe application is also increasingly growing. This relates to the alloys’ phase stability, in particular, the control required over unexpected phase decompositions resulting from solute segregation at grain boundaries. Yet, the mechanisms of co-segregation and grain boundary phase decomposition in multi-component alloys are rather challenging to explore. In fact, quantitative investigation of grain boundary behaviors is mostly conducted for binary and a few ternary alloys. In this work, we apply the recently introduced CALPHAD-integrated density-based formalism [RSC Advances 10 (2020) 26728-26741] for considering co-segregation phenomena in alloys with an arbitrary number of components —the term ‘co-segregation’ here refers to co-evolution and any mutual interplay among the solute atoms during their interaction with a grain boundary. Quaternary Fe-Co-Mn-Cr alloy system is studied. We present two major advances beyond previous results: First, a co-segregation-induced multi-component grain boundary spinodal decomposition is quantitatively simulated for the first time. We found that in addition to its low cohesive energy and asymmetrical mixing enthalpy due to magnetic ordering, Mn plays a leading role in triggering interfacial phase decomposition by having a relatively large, concentration-dependent atomic mobility. Second, as an alternative to grain boundary phase diagrams proposed for binary and ternary alloys, we introduce the concept of co-segregation maps for grain boundary segregation screening and design in multi-component alloys. Applying the co-segregation maps, the nonlinear Mn and Cr co-segregation are discussed. Depicted on the alloying composition and phase space, the co-segregation maps enable the required insights to guide a safer, more controlled design of high-entropy alloys.
KW - High-Entropy Materials
KW - Density-based Phase-Field Modelling
KW - CALPHAD
KW - Alloys' Safety
PY - 2023
DO - https://doi.org/10.1016/j.jallcom.2022.167717
SN - 0925-8388
VL - 933
SP - 1
EP - 12
PB - Elsevier
CY - Lausanne
AN - OPUS4-56274
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Boerner, Andreas
A1 - Saliwan Neumann, Romeo
A1 - Schneider, M.
A1 - Laplanche, G.
T1 - Influence of machining on the surface integrity of high- and medium-entropy alloys
N2 - High- and medium-entropy alloys (HEAs) are a quite new class of materials. They have a high potential for applications from low to high temperatures due to the excellent combination of their structural properties.
Concerning their application as components; processing properties, such as machinability, have hardly been investigated so far. Hence, machinability analyses with a focus on the influence of the milling process and its basic parameters (cutting speed, feed per cutting edge) on the resulting surface integrity of specimens from an equiatomic high- (CoCrFeMnNi) and a medium- (CoCrNi) entropy alloy have been carried out. A highly innovative milling process with ultrasonic assistance (USAM) was compared to conventional milling processes.
Recent studies have shown that USAM has a high potential to significantly reduce the mechanical load on the tool and workpiece surface during milling. In this study, the basic machining and ultrasonic parameters were systematically varied. After machining, the surface integrity of the alloys was analyzed in terms of topography, defects, subsurface damage, and residual stresses. It was observed that USAM reduces the cutting forces and increases the surface integrity in terms of lower tensile residual stresses and defect density near the surfaces for the CoCrFeMnNi alloy. It was shown that the cutting forces and the metallurgical influence in the sub surface region are reduced by increasing the cutting speed and reducing the feed rate per cutting edge. With the CoCrNi alloy, the tool revealed severe wear. As a result, for this alloy no influence of the parameters on the machinability could be determined.
KW - High Entropy Alloy
KW - Medium Entropy Alloys
KW - Ultrasonic assited machining
PY - 2022
DO - https://doi.org/10.1016/j.matchemphys.2021.125271
SN - 0254-0584
VL - 275
SP - 125271
PB - Elsevier B.V.
AN - OPUS4-53606
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Murugan, Jegatheesan
T1 - Extending Grain Boundary Phase Diagrams to Multi-Phase Boundary Diagrams
N2 - Phase diagrams serve as fundamental blueprints for comprehending material behaviour and guiding material design. However, the phase diagrams are largely available only for the bulk phases. The thermodynamic properties and phase behaviour of defects, such as grain boundaries (GBs) and phase boundaries (PBs), are equally important for the safe design of materials. Recently, we developed CALPHAD-integrated density-based phase field model (DPF) to calculate the thermodynamic data of GBs. In the model, the GB was represented by a continuous relative atomic density field with reference to a single bulk density and a Gibbs free energy functional was derived. In this work, we extend the DPF model by re-deriving the Gibbs free energy functional for PBs lying between heterogeneous bulk phases of different atomic densities. Here, we use phase-specific atomic densities to normalize the phase properties on either side of the PB such that the relative density fields are continuous across the interface. Using the model, the multi-phase interfacial thermodynamic data are obtained and related phase boundary diagrams are constructed. We study binary and ternary Fe-Mn-X alloy systems. In the Fe-Mn multi-phase boundary diagram, a shrinkage in the α-ferrite region is observed. Integrated with CALPHAD databases, the developed model may be used to calculate the segregation of solute to the PBs, paving way to manipulate segregation behaviour for microstructure design.
T2 - FEMS 2025 EUROMAT
CY - Granada, Spain
DA - 14.09.2025
KW - Phase boundary diagrams
KW - Interface thermodynamics
KW - CALPHAD
PY - 2025
AN - OPUS4-64425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Darvishi Kamachali, Reza
T1 - Co-segregation phenomena and stability issues in high-entropy alloys using density-based phase-field modelling
N2 - Several recent studies have revealed that the phase decomposition in medium- and high-entropy alloys is triggered by solute segregation at grain boundaries. The chemically complex nature of these alloys already clues that such segregation in materials should be something more than the interaction between solutes and grain boundary, but also affected by the solute-solute interactions during the segregation. In fact, experiments indicate the significance of such solute-solute interaction. Yet, the mechanisms of co-segregation in multi-component alloys are rather challenging to explore and rarely studied quantitatively. Recently, a CALPHAD-integrated density-based phase-field model has been proposed for studying grain boundary phenomena. Several applications of this model have shown its expansive capacity for investigating grain boundary segregation and phase behavior. In this talk, the applications of this model to studying co-segregation phenomena and grain boundary phase diagrams in multi-component alloys are presented ––the term ‘co-segregation’ here refers to co-evolution and any mutual interplay among the solutes and grain boundary during the segregation. In particular, the iron-based ternary and quaternary alloys are discussed. I show how a grain boundary may have its own miscibility gap and how this immiscibility can influence the co-segregation behavior. As an alternative to grain boundary phase diagrams, rather suited for binary and ternary alloys, a new concept of co-segregation maps for screening and segregation design in multi-component alloys is presented. Applying the co-segregation maps, the nonlinear Mn and Cr co-segregation in Fe-Co-Mn-Cr is discussed.
T2 - 19th International Conference on Diffusion in Solids and Liquids (DSL-2023)
CY - Crete, Greece
DA - 26.06.2023
KW - CALPHAD
KW - Co-segregation
KW - Phase-field Simulation
PY - 2023
AN - OPUS4-57965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
A1 - Wang, L.
T1 - Elastic energy of multi-component solid solutions and strain origins of phase stability in high-entropy alloys
N2 - The elastic energy of mixing for multi-component solid solutions is derived by generalizing Eshelby's sphere-in-hole model. By surveying the dependence of the elastic energy on the chemical composition and lattice misfit, we derive a lattice strain coefficient λ*. Studying several high-entropy alloys and superalloys, we propose that most solid solution multi-component alloys are stable when λ*<0.16, generalizing the Hume-Rothery atomic-size rule for binary alloys. We also reveal that the polydispersity index δ, frequently used for describing strain in multi-component alloys, directly represents the elastic energy e with e=qδ², q being an elastic constant. Furthermore, the effects of (i) the number and (ii) the atomic-size distribution of constituting elements on the phase stability of high-entropy alloys were quantified. The present derivations and discussions open for richer considerations of elastic effects in high-entropy alloys, offering immediate support for quantitative assessments of their thermodynamic properties and studying related strengthening mechanisms.
KW - Ordering
KW - High-entropy alloys
KW - Alloy design
KW - Strain energy
KW - Phase stability
PY - 2022
DO - https://doi.org/10.1016/j.scriptamat.2021.114226
SN - 1359-6462
VL - 206
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Engelking, Loenz
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Eissel, Antonia
A1 - Treutler, Kai
A1 - Wesling, Volker
T1 - Herstellung beanspruchungsgerechter Oberflächen durch Kombination innovativer additiver und abtragender Fertigungsschritte an hochbelasteten Komponenten
N2 - Die additive Fertigung mittels Schweißverfahren bietet große ökonomische Vorteile für eine ressourceneffiziente Bauteilherstellung. Offene Fragen bezüglich Homogenität, Anisotropie der Schweißgefüge und den damit verbundenen Bauteileigenschaften stehen einer wirtschaftlichen Verarbeitung oftmals im Wege. Finale Bauteilgeometrie und Oberflächengüte erfordern meist komplementäre subtraktive Fertigungsschritte. Werkstoffe für hochbelastbare Komponenten sind oftmals schwer span bar. In einem Vorhaben der BAM und des ISAF wurde untersucht, wie die Modifikation der AM-Schweißzusätze und das ultraschallunterstützte Fräsen (US) die Zerspanungssituation verbessern. Der vorliegende Artikel stellt wesentliche Zusammenhänge zwischen Legierung, Gefüge und Zerspanung zweier schwer spanbarer Hochleistungslegierungen (FeNi und CoCr) dar. Großes Potenzial zeigte neben dem US die Modifikation mit Zr und Hf bei Zulegierung in das Schweißgut mittels Beschichtung von Massivdrähten bzw. Herstellung von Fülldrähten.
KW - Additive Fertigung (AM)
KW - Ultraschallunterstütztes Fräsen (US)
KW - Werkstoffmodifikation
KW - Oberflächenintegrität
KW - Zerspanbarkeit schwer spanbarer Legierungen
KW - Ressourceneffizienz in Prozessketten
KW - Hochleistungslegierungen
KW - Technologietransfer für KMU
PY - 2025
SN - 978-3-96144-304-8
VL - 2026
SP - 290
EP - 298
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-65246
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
T1 - On the modeling of creep anisotropy of single Crystal Superalloys at low temperatures and high stresses
N2 - Low-Temperature High Stress (LTHS) creep plays a crucial role in Ni-base Superalloys, particularly affecting components like blades near the root. Below 850°C, the precipitate microstructure remains stable, characterized by periodically arranged ’ cubic precipitates surrounded by the -matrix. In these conditions, macroscopic traces of cubic slip have been observed in <111> oriented tensile specimens, whereas their microscopic origin has been a topic of debate [1]. Later, it was shown by Discrete Dislocations simulations [2] that the apparent cubic slip is rather due to a lack of hardening in <111> specimens, which is related to the special dislocation structures that develop in this case. Furthermore, in LTHS conditions, Superlattice Intrinsic, Extrinsic Stacking Faults (SISF/SESF), or micro-twins are also frequently reported in crept specimens. Usually, these mechanisms are investigated separately, so that a unified picture and a detailed understanding of these mechanisms and their activation conditions have only recently emerged in the literature, despite the intensive investigations of the last decades [3-5].
The objective of this work is to develop a dislocation-based constitutive law that includes these recent developments. In particular, the pseudo-cubic slip mechanism is considered as resulting from the lack of hardening in <111> oriented tensile specimens and is represented by a novel estimate of the back-stresses based on the spectral decomposition of a tensorial representation of the back-stress. An additional novelty is that SISF- and SESF-related slip systems are accounted for as distinct slip systems with corresponding dislocation densities. The model has been implemented as a user-defined constitutive law for commercial Finite Element codes and identified as well as validated with data from the literature obtained with <001>, <011> and <111> oriented crystals [3,6]. It can be used in combination with a Representative Volume Element of the grain structure for simulation of creep in polycrystalline superalloys, including additively manufactured materials [7].
T2 - Materials Structure and Micromechanics of Fracture
CY - Brno, Czech Republic
DA - 23.06.2025
KW - Creep
KW - Superalloy
KW - Crystal plasticity
KW - Single crystal
KW - Model
PY - 2025
AN - OPUS4-63551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ganesh, Rahul
T1 - Numerical calculation of ΔCTOD for thermomechanical fatigue crack growth
N2 - The cyclic crack tip opening displacement ΔCTOD is a promising loading Parameter to quantify the crack propagation under thermomechanical fatigue (TMF). In this work, suitable techniques are investigated and compared for an accurate calculation of ΔCTOD under TMF loading using a viscoplastic temperature dependent material model.
It turned out that collapsed special crack tip elements give the best results. An efficient FEM-technique is developed to simulate the incremental crack growth by successive remeshing, whereby the deformations and internal state variables are mapped from the old mesh onto the new one. The developed techniques are demonstrated and discussed for two-dimensional examples like TMF-specimens. Recommendations are made regarding important numerical control parameters like optimal size of crack tip elements, length of crack growth increment in relation to plastic zone size and ΔCTOD value.
T2 - 53. Tagung des Arbeitskreises "Bruchmechanik und Bauteilsicherheit"
CY - Online meeting
DA - 18.02.2021
KW - Crack tip opening displacement
KW - Thermomechanical fatigue
KW - Crack growth
PY - 2021
AN - OPUS4-52520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Keshmiri, Hamid
T1 - Plasmon-enhanced diffractive supercells
N2 - Multiple diffractive surface modulations can concurrently couple the light to several electromagnetic surface waves. We present a multi-resonant plasmonic supercell structure with a broad range of applicability in harvesting the light over an extensive wavelength range and angles of incidence.
T2 - Molecular Plasmonics 2023
CY - Jena, Germany
DA - 11.05.2023
KW - Optics
PY - 2023
AN - OPUS4-59248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Askar, Enis
A1 - Aksam, A.
A1 - Brandes, E.
A1 - Markus, D.
A1 - Stolz, T.
T1 - Berechnung der Explosionsbereiche von Alkoholen, Ketonen und halogenierten Kohlenwasserstoffen im Gemisch mit Inertgasen
N2 - Die Explosionsbereiche für Dreistoffsysteme aus Brennstoff Inertgas und Luft wurden nach dem Modell der konstanten adiabatischen Flammentemperaturprofile berechnet. Für die Parametrisierung des halbempirischen Modells muss der Explosionsbereich für ein bestimmtes Dreistoffsystem aus Brennstoff, Inertgas und Luft bekannt sein. Dann lassen sich Explosionsbereiche desselben Brennstoffs mit einem beliebigen Inertgas und bei einer beliebigen Temperatur berechnen. Ergänzend zu früheren Arbeiten, in denen die Explosionsbereiche für Brenngase aus der homologen Reihe der Alkane und Alkene berechnet worden sind, wurden nun die Berechnungen für 1-Propanol, Aceton und Difluormethan durchgeführt. Als Inertgase wurden neben Stickstoff und Kohlendioxid auch die Edelgase Argon und Helium berücksichtigt.
Für die Berechnung der Explosionsbereiche in Systemen mit Helium, ist das Modell erweitert worden, so dass auch die Transporteigenschaften (d.h. Wärmeleitfähigkeit, Diffusionskoeffizient) der Komponenten berücksichtigt werden. Weiterhin ist eine Möglichkeit zur praxisnahen Berechnung der Spitze des Explosionsbereichs implementiert worden. Die Ergebnisse zeigen insgesamt, dass die Berechnung der Explosionsbereiche für Alkohole, Ketone und halogenierte Kohlenwasserstoffe mit ähnlicher Genauigkeit wie für Alkane und Alkene möglich ist. Die vorgenommenen Modifikationen sind geeignet, um auch eine Berechnung für Gasgemische mit Helium durchzuführen, dessen starke inertisierende Wirkung im Vergleich zu den Inertgasen
Argon oder Stickstoff vor allem auf den stark unterschiedlichen Transporteigenschaften beruht.
KW - Explosionsgrenzen
KW - Inertisierung
KW - Modell der konstanten Flammentemperaturen
KW - Explosionsschutz
PY - 2020
DO - https://doi.org/10.7795/310.20200199
SN - 0030-834X
VL - 130
IS - 1
SP - 25
EP - 29
AN - OPUS4-50945
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Tim
A1 - Huber, Norbert
T1 - Microstructure and orientation effects on microcompression-induced plasticity in nanoporous gold
N2 - Understanding the plastic deformation of nanoporous metals requires a detailed examination of their small-scale microstructural features. In this work, we present a computational study of micropillar compression in single crystal nanoporous gold (NPG) using crystal plasticity. This approach enables a systematic investigation of three key microstructural effects, including ligament size (50 ≤ 𝑙 ≤ 400 nm), solid fraction (0.2 ≤ 𝜑 ≤ 0.3), and initial crystal orientation ([001] and [111] ̄ ), on the plastic response far beyond yielding. After validation against experimental data, the study reveals that, in line with the ’smaller is stronger’ trend, besides the yield strength, the strain hardening rate also increases as ligament size decreases. Moreover, the strain hardening rate follows a power-law scaling with solid fraction, similar to the yield strength. The analysis of two distinct crystal orientations presents findings contrasting with previous assumptions. While the yielding onset remains orientation-independent, as expected, an increase in the strain hardening rate emerges for the harder [11-1] orientation with continued compression. An effect that becomes more pronounced with increasing solid fraction and decreasing ligament size. Under these conditions, harder orientations also amplify local stress heterogeneity. Notably, the stress distribution in NPG is nearly twice as wide as that observed in the single crystal bulk material (𝜑 = 1.0). Compared to the crystal plasticity approach, traditional isotropic plasticity predicts more uniform local stress fields.
KW - Nanoporous gold
KW - Microcompression
KW - Plasticity
KW - Size effect
KW - Micromechanics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650137
DO - https://doi.org/10.1016/j.actamat.2025.121798
SN - 1359-6454
VL - 304
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-65013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baensch, Franziska
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
A1 - Habib, Abdel Karim
T1 - Damage evolution detection in a pipeline segment under bending by means of acoustic emission
N2 - A steel pipeline segment of 2.5 m length was subjected to quasi-static four-point bending load in three steps for studying the initial cracking and damage accumulation based on the Acoustic Emission (AE) technique and by the direct current potential drop (DCPD) technique. For the latter, a new post-test analysis method was established.
AE is found more sensitive to crack initiation than DCPD. Formation of mesoscopic and macroscopic cracks as well as their closure and the resulting friction generate weighted peak frequencies below 400 kHz, whereas microscopic cracking produces AE with broad band spectra identifiable by weighted peak frequencies above 400 kHz. Critical states alike the maximum load level and the leak opening were accompanied by peak amplitudes above 85 dBAE. This rather fundamental study provides a data base for possibly developing advanced strategies of detection and alarm systems based on acoustic monitoring of pipelines, or at least, steel structures.
KW - Crack
KW - Accoustic emission
KW - Frequency domain
KW - Potential drop technique
KW - Fracture
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565171
DO - https://doi.org/10.1016/j.ijpvp.2022.104863
SN - 0308-0161
VL - 201
IS - 104863
SP - 1
EP - 9
PB - Elsevier Science
CY - Amsterdam
AN - OPUS4-56517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Suárez Ocano, Patricia
A1 - Agudo Jácome, Leonardo
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Fries, S. G.
T1 - Data regarding the experimental findings compared with CALPHAD calculations of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy
N2 - This contribution contains the raw data used to compare experimental results with thermodynamic calculations using the CALPHAD method, which is related to the research article “The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: experimental findings and comparison with calculations using the CALPHAD method” [1] , and therefore this article can be used as a basis for interpreting the data contained therein. The AlMo0.5NbTa0.5TiZr refractory superalloy was characterized in the cast and annealed condition (1400 °C for 24 h) in order to measure grain size and to identify and measure the size and area fraction of the phases present. The raw data of this article include X-ray diffraction (XRD) measurements, microstructural characterization by scanning and transmission electron microscopy (SEM and TEM), and elemental analysis by energy dispersive X-ray spectroscopy (EDX). XRD includes the determination of phases and the lattice parameters (A2, B2, and hexagonal structure). Microstructural analysis by scanning and transmission electron microscopy includes (1) identification of composition, size, and volume fraction of the present phases and (2) determination of grain size. Based on these experimental data, it is possible to identify similarities and discrepancies with the data calculated using the CALPHAD method for the alloy under study in Ref. [1] , which provides the basis for better and more efficient development of reliable databases.
KW - Microstructural characterization
KW - Refractory high entropy alloys
KW - Scanning electron microscopy
KW - Transmission electron microscopy
PY - 2023
DO - https://doi.org/10.17632/d742ccty5f.4
PB - Mendeley Data
CY - Oxford, UK
AN - OPUS4-56861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Elfetni, Seif
A1 - Darvishi Kamachali, Reza
T1 - Application of deep learning to multi-phase-field modelling and simulation
N2 - Recent advances in Deep Learning (DL) have significantly impacted the field of materials modelling. DL tools have been recently considered as promising tools to address the complex relationships among processing, microstructure and property of materials. The thermal stability of polycrystalline materials is a highly interesting and complex problem that could be addressed using DL techniques. The Multi-Phase-Field (MPF) method has emerged as a powerful tool for addressing grain growth phenomena from multiple perspectives. Unlike sharp-interface based methods, the MPF approach bypasses the need for detailed information on individual grains. In this work, we use DL to address issues related to MPF simulations of grain growth including numerical efficiency, computing speed, and resource consumption. This presents specific challenges for high-performance computing (HPC) due to the large datasets and complex computations required by both MPF and DL methods. We study various 3D microstructure settings with the goal of accelerating the simulation process while exploring different physical effects. In particular, the impact of grain boundary and triple junction energies on grain growth are to be investigated. The results will be presented in terms of the evolving size and shape distribution of the grains.
T2 - Euromat 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Phase-Field Simulation
KW - Microstructure Evolution
KW - Physics-informed Neural Network
KW - Machine Learning
PY - 2023
AN - OPUS4-58225
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kindrachuk, Vitaliy
T1 - Computational investigation of DGG kinetics by phase-field method
N2 - Non-equilibrium microstructure evolution in additive manufacturing (AM) is a major barrier for establishing a safe and sustainable application of AM in industrial processes. The constant heat source in the AM continuously affects the just-solidified grains beneath the melting pool, leading to directional grain growth (DGG). While real-time measurements of the non-equilibrium microstructure evolution is challenging, here developing a computational framework to systematically explore DGG becomes imperative.
We have advanced a comprehensive approach, integrating mean-field modeling and phase-field simulations, to elucidate the dynamics of DGG under an external driving force. Our simulations unveil a steady-state power-law grain growth kinetics during DGG, characterized by the interplay between curvature-driven dynamics at grain boundary junctions and directional driving forces.
T2 - Tagung DGM Additive Fertigung
CY - Bremen, Germany
DA - 12.06.2024
KW - Directional grain growth
KW - Phase-field simulation
KW - Additive manufacturing
PY - 2024
AN - OPUS4-60750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Kianinejad, Kaveh
T1 - Multiscale Modelling of Creep Anisotropy in Additively Manufactured IN738LC
N2 - Excellent creep resistance at elevated temperatures, i.e. T / Tm> 0.5, due to gamma-gamma’ microstructure is one of the main properties of nickel-based superalloys. Due to its great importance for industrial applications, much research has been devoted to understanding the underlying deformation mechanism in a broad spectrum of temperature and loading conditions. Additive Manufactured (AMed) nickel-based superalloys, while being governed by similar \gamma-gamma’ microstructure, exhibit AM-process specific microstructural characteristics, such as columnar grains, firm crystallographic texture (typically <001> fibre texture parallel to build direction) and compositional inhomogeneity, which in turn leads to anisotropic creep response in both stationary and tertiary phases.
Despite the recent insights on the correlation between process parameters and the resulting microstructure, these materials' anisotropic creep behaviour and corresponding deformation mechanism are insufficiently understood. One reason is the lack of capable material models that link the microstructure to the mechanical behaviour. Within the present work, a multiscale approach has been developed to overcome this challenge by combining microstructure-based mesoscale and phenomenological macroscale models. The mesoscale model utilizes the Crystal Plasticity Finite Element Method (CPFEM) to include the microstructural characteristics and the relevant deformation mechanism on the polycrystalline scale. The mesoscale model was then used to perform virtual creep experiments required to calibrate the macroscale model.
The developed approach has been applied to characterise the creep behaviour of AMed IN738LC. The effect of different slip systems, crystallographical texture, grain morphology, and Grain Boundary Sliding (GBS) on creep anisotropy at 850°C has been investigated. The approach's ability to capture the AM-specific characteristics and link them to the observed macroscale anisotropic response has been demonstrated, and the contribution of primary underlying deformation mechanisms to creep anisotropy has been elucidated.
KW - Creep anisotropy
KW - Crystal plasticity
KW - Addtively manufactured Nickel-based Alloys alloy
PY - 2025
SP - 1
EP - 135
PB - RWTH Aachen
CY - Aachen
AN - OPUS4-64598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A. I.
A1 - Fedelich, Bernard
A1 - Viguier, B.
A1 - Schriever, Sina
A1 - Svetlov, I. L.
A1 - Petrushin, N. V.
A1 - Saillard, R.
A1 - Proietti, A.
A1 - Poquillon, D.
A1 - Chyrkin, A.
T1 - Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C
N2 - A γ-analogue of the superalloy CMSX-4 that does not contain the strengthening γ′ -phase and only consists of the γ-solid solution of nickel has been designed, solidified as single-crystals of different orientations, and tested under creep conditions in the temperature range between 1150 and 1288 °C. The tests have revealed a very high creep anisotropy of this alloy, as was previously found for CMSX-4 at supersolvus temperature of 1288 °C. This creep anisotropy could be explained by the dominance of 〈011〉{111} octahedral slip. Furthermore, the analysis of the creep data has yielded a high value of the creep activation energy, Qc≈442 kJ/mol, which correlates with the high activation energy of Re diffusion in Ni. This supports the hypothesis that dislocation motion in the γ-matrix of Re-containing superalloys is controlled by the diffusion of the Re atoms segregating at the dislocation core. The Norton stress exponent n is close to 5, which is a typical value for pure metals and their alloys. The absence of γ′ -reprecipitation after high-temperature creep tests facilitates microstructural investigations. It has been shown by EBSD that creep deformation results in an increasing misorientation of the existing low angle boundaries. In addition, according to TEM, new low angle boundaries appear due to reactions of the a/2 〈011〉 mobile dislocations and knitting of new networks.
KW - Nickel alloys
KW - Single-crystals
KW - Creep
KW - Electron microscopy
KW - Deformation mechanisms
PY - 2021
DO - https://doi.org/10.1016/j.msea.2021.141880
SN - 0921-5093
VL - 825
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
A1 - Feldmann, Titus
A1 - Haftaoglu, Cetin
A1 - Nolze, Gert
A1 - Schriever, Sina
A1 - Epishin, A.
A1 - Camin, B.
A1 - Lopez-Galilea, I.
A1 - Ruttert, B.
A1 - Theisen, W.
T1 - Untersuchung des Kriechverhaltens einer Nickelbasis-Superlegierung bei ultrahohen homologen Temperaturen und Anwendung auf das heiß-isostatische Pressen (HIP)
N2 - Mit Hilfe des HIP-Verfahrens („Hot Isostatic Pressing“) werden Poren in der einkristallinen Nickel-Basis Superlegierung CMSX-4 kontinuierlich geschrumpft und dadurch die nach der Erstarrung und der Wärmebehandlung vorhandene Porosität stark reduziert. In diesem Beitrag werden experimentelle und numerische Untersuchungen zu den Mechanismen der Porenschrumpfung zusammengefasst. Es zeigt sich, dass das Verformungsverhalten während Kriechversuchen bei der HIP-Temperatur durch Versetzungsgleitung auf oktaedrischen Ebenen dominiert wird.
Dagegen zeigen Messungen der Porositätsabnahme und Simulationen des Porenschließens, dass die Kinetik der Porenschrumpfung durch das Phänomen der Leerstellendiffusion zwischen Poren und Kleinwinkelkorngrenzen („Low Angle Boundary“, LAB) bestimmt wird. Im Gegensatz führt die klassische Kristallviskoplastizität zu einer systematischen Überschätzung dieser Kinetik. Der scheinbare Widerspruch lässt sich auflösen, wenn man bedenkt, dass auf der Skala der Poren Versetzungsquellen nicht gleichmäßig verteilt sind, wie in der konventionellen Kristallplastizität implizit angenommen wird. Stattdessen wird in einem weiterführenden Modell davon ausgegangen, das Kleinwinkelkorngrenzen (LABs) als Versetzungsquellen fungieren, während die Scherspannungen sehr stark in der Nähe der Poren lokalisiert sind, was die Emission von Versetzungen deutlich reduziert.
T2 - Langzeitverhalten warmfester Stähle und Hochtemperaturwerkstoffe
CY - Online meeting
DA - 27.11.2020
KW - HIP
KW - Superlegierung
KW - Kriechen
PY - 2020
SN - 978-3-946885-95-5
VL - 2020
SP - 28
EP - 39
PB - Forschungsvereinigung Warmfeste Stähle und Hochtemperaturwerkstoffe
AN - OPUS4-51796
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marschall, Niklas
T1 - Phase Decomposition in Magnetic FeMnNiCoCu Alloy System
N2 - Phase decomposition in multi-component high-entropy alloys (HEAs) can take complex routes, on the one hand, leading to various safety concerns during their service and, on the other hand, opening vast opportunities for intelligent alloy design. Insights into a controlled decomposition of initially homogeneous HEAs are therefore essential. In this study, we combine the recently developed multi-component elastic energy theory with CALPHAD databases to study potentially magnetic FeMnNiCoCu alloy system. In a first approximation, the elastic energy is added to the Gibbs free energy to reconstruct the thermodynamic phase diagrams and consequent phase decompositions. Our results show that depending on the alloy composition and the temperature, Cu-rich and FeCo-rich phases emerge, which lead to the formation of distinct magnetic phases of different extents. The spatial redistribution of elements is studied through Fourier analysis, auto-, and cross-correlation, revealing the contribution of the thermodynamic, kinetic and elastic driving forces throughout this process. These dissembled analysis methods contribute to a more comprehensive understanding of multi-component alloys and the role of elastic energy in their phase decomposition.
T2 - MSE2024
CY - Darmstadt, Germany
DA - 23.09.2024
KW - High-Entropy Alloy
KW - Elasticity
KW - Spinodal Decomposition
KW - FeMnNiCoCu
PY - 2024
AN - OPUS4-62341
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wang, Lei
A1 - Darvishi Kamachali, Reza
T1 - Density-based Thermodynamics of Microstructure Defects
N2 - Systematic microstructure design requires reliable thermodynamic descriptions and phase diagrams of each and all microstructure elements. While such descriptions are well established for most bulk phases, thermodynamic assessment of crystal defects is greatly challenged by their individualistic aspects. In this talk, we present a density-based thermodynamic concept to describe defects based on available bulk thermodynamic data. Here dealing with grain boundaries (GBs), we apply this concept to compute GB (phase) diagram. Applications to segregation engineering of GBs in bulk and nanocrystalline alloys will be presented. We further develop this model to include the effect of elastic interactions due to atom size mismatch and obtain the corresponding GB (phase) diagram for the ternary Al-Cu-Li system.
T2 - TMS 2021
CY - Online meeting
DA - 15.03.2021
KW - Microstrucrue Design
KW - Density-based Thermodynamics
PY - 2021
AN - OPUS4-52337
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kianinejad, Kaveh
A1 - Czediwoda, Fabian
A1 - Glatzel, U.
A1 - Völkl, R.
A1 - Stöhr, B.
A1 - Ávila Calderón, Luis
A1 - Schriever, Sina
A1 - Saliwan Neumann, Romeo
A1 - Fedelich, Bernard
A1 - Darvishi Kamachali, Reza
T1 - Microstructure-based modelling of the anisotropic creep behaviour in additively manufactured INCONEL 718
N2 - The existing gap in the adequate prediction of the microstructure-property relationships remains a significant barrier to the safe application of the additively manufactured materials. This challenge is fundamentally tied to the intricate microstructural defects that emerge during the processing. Systematic microstructure-based modelling can offer solutions to address this bottleneck.
In this work, we utilize a crystal plasticity model, developed for gamma''-strengthened Ni-base alloys and calibrated with single crystal tensile and creep tests of Inconel 718. By systematically refining the representative volume element complexity---from equiaxed to elongated grain morphologies, and from unimodal to bimodal orientation and grain size distributions---we demonstrate how each layer of structural realism contributes to the model’s predictive capacity.
Creep tests of laser-based powder bed fusion (PBF-LB/M) manufactured samples in three orientations (with the tensile axis parallel, perpendicular, and 45° tilted relative to the building direction) were performed at 650° C, accompanied by electron backscatter secondary diffraction measurements. The results of our simulations reveal that the bimodal grain morphology and crystallographical texture significantly influence the observed creep anisotropy. We show that the elongated grain structure combined with grain boundary sliding plays a major role in the creep response, specifically in tilted specimens.
KW - Additive manufactured Ni-base superalloys
KW - Creep Anisotropy
KW - Crystal plasticity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646884
DO - https://doi.org/10.1016/j.msea.2025.149029
VL - 945
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-64688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Murugan, Jegatheesan
T1 - Thermodynamics of Grain Boundary Segregation in Fe-Ni-Cr Alloy Systems
N2 - Phase stability in multi-components alloy systems is still largely unknown, especially at the internal interfaces. Grain boundary (co-)segregation is one of the main causes of instability and therefore safety issues in microstructures. In this work, the segregation in FCC Fe-Ni-Cr alloy system, which is the base for several steels, super-alloys and high entropy alloys, is studied. The density-based phase-field model is advanced to compute the segregation of Fe, Ni and Cr at the grain boundary corresponding to the bulk composition. Here the relative density of the grain boundary to the bulk is the mean-field parameter of the model. The necessary thermodynamic parameters of the bulk are obtained from the CALPHAD database. We performed high-throughput screening of the elemental segregation at the grain boundary across the stable bulk compositions at different temperatures (723 K, 1023 K and 1323 K). The results reveal complex enrichment/depletion of each element depending on the alloy composition and temperature. Opposite segregation of Ni and Cr and co-segregation of Ni and Fe is observed for almost all compositions at 723 K, but a changing trend is observed with increasing temperature. We discuss the origin and consequences of these segregation behaviours in the light of magnetic ordering effects.
T2 - Materials Science and Engineering (MSE) 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Segregation
KW - Grain boundaries
KW - CALPHAD
PY - 2024
AN - OPUS4-62343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kostenko, Yevgen
T1 - Harmonizing Viscoplastic Material Model Application within the BMBF-Project “DigitalModelling” of the Platform Material Digital- Basic Idea, General Strategy and Current Status
N2 - For decades, Germany stands for excellent cutting-edge research in the field of so-called higher-value constitutive visco-plastic material models and can draw on a large and globally unique pool of material data. However, both the data and the model structure are extremely heterogeneous and sometimes fundamentally different from research center to research center and from industrial partner to industrial partner. To address the heterogeneity in the material model landscape appropriately, an adaptable material model for the specific application and the specific material is required. The relevant parameters for the adapted material model must be identified as objectively and automatically as possible. To achieve a potentially real-time capable implementation, the material model equation system should be abstracted.
The “DigitalModeling” project, organized within the German Platform initiative Material Digital, aims to create a standard and an interface that harmonize the scientific and technical development of constitutive, visco-plastic material models, increase their visibility and maximize the productivity of future research funding. This presentation summarizes the basic idea, the strategy behind it as well as the current status of the project, which was started beginning of 2024.
T2 - vgbe Workshop with Technical Exhibition Materials & Quality Assurance
CY - Bergen, Norway
DA - 07.05.2025
KW - Visco-plastic Material Model
KW - Simulation Workflows
KW - Ontologies
KW - Digitalization
PY - 2025
AN - OPUS4-64043
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Darvishi Kamachali, Reza
T1 - Interfacial Spinodals
N2 - Despite their finite spatial extent, interfaces can have profound impacts on microstructure properties. This is because of their distinct phase-like properties distinguishing them from the adjacent homogeneous bulk structure. When noticed by solute atoms, interfaces can experience their own chemical phase changes. In this talk, we investigate the constrained states of chemically decomposed phases at interfaces. A density-based theory of interfaces is proposed to describe the confined chemical decomposition at general grain boundaries. Here the grain boundary is viewed as a lesser dense, defected structure with reference to the corresponding bulk structure. Using this picture, the thermodynamic origins of interfacial spinodal phenomena are revealed. We also show that transient interfacial spinodals can be activated over a large alloy composition range, enabling kinetic engineering of interfacial chemistry.
T2 - TMS 2021
CY - Online meeting
DA - 15.03.2021
KW - Microstrucrue Design
KW - Spinodal Decomposition
KW - Interfacial Spinodal
PY - 2021
AN - OPUS4-52338
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gesell, Stephan
A1 - Ganesh, R.
A1 - Fedelich, Bernard
A1 - Kuna, M.
A1 - Kiefer, B.
T1 - Numerical calculation of 𝛥CTOD to simulate fatigue crack growth under large scale viscoplastic deformations
N2 - Crack propagation under low cycle fatigue and thermomechanical fatigue is characterized by high plastic and creep strains that extend over large regions around the crack, so that concepts of linear-elastic fracture mechanics cannot be applied. In these cases, the cyclic crack tip opening displacement 𝛥CTOD is a promising loading parameter to quantify crack growth. In this work, suitable definitions and Finite Element techniques are investigated and compared for an accurate calculation of 𝛥CTOD under cyclic mechanical and/or thermal loading. A viscoplastic temperature dependent material model of Chaboche-type is used along with large strain settings, specified for the austenitic cast iron Ni-resist. Extensive two-dimensional analyses of Single Edge Notch Tension specimens revealed that collapsed special crack tip elements are superior compared with commonly used regular quadrilateral 8-node elements. At the same level of accuracy of 𝛥CTOD, they require an about ten times coarser mesh and show less sensitivity
w.r.t. element size for both stationary and propagating cracks. In order to simulate fatigue crack growth, an efficient, fully automated FE-technique is developed for an incremental crack propagation by successive remeshing, whereby the deformations and internal state variables are mapped from the old mesh onto the new one. Recommendations are made regarding important numerical control parameters like optimal size of crack tip elements, length of crack growth increment in relation to plastic zone size and 𝛥CTOD value.
KW - Crack tip opening displacement
KW - Finite element analysis
KW - Crack growth
KW - Low cycle fatigue
PY - 2023
DO - https://doi.org/10.1016/j.engfracmech.2023.109064
VL - 281
IS - 109064
SP - 1
EP - 23
PB - Elsevier Ltd.
AN - OPUS4-56857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Darvishi Kamachali, Reza
T1 - Grain Boundary Segregation Design using CALPHAD-integrated Phase-Field Modelling
N2 - A main source of current challenges in materials science and engineering is the ever-increasing complexity in materials chemistry and processing resulting in complex microstructures, making the assessment of process-microstructure-property-performance relations difficult, even unmanageable. Here the computational materials science is facing the same situation. In this talk, I share a viewpoint that the complexities in chemistry, processing and microstructures can be circumscribed by integrating existing knowledges of bulk thermodynamics and kinetics to the unknown thermodynamics and kinetics of microstructure elements. To this end, I discuss several successful examples on grain boundary segregation engineering how this scientific advance can be conducted. A roadmap is proposed, beginning to form on generalizing the concept of phase diagrams.
T2 - ICAMS Advance Discussions: Advanced models for microstructure evolution – process-microstructure-property relationships
CY - Bochum, Germany
DA - 26.10.2022
KW - Microstructure Design
KW - CALPHAD
KW - Phase-Field Simulations
KW - Machine Learning
KW - Phase Diagrams
PY - 2022
AN - OPUS4-56348
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Creep behavior and microstructural evolution of LPBF 316L
N2 - This presentation shows some experimental results of the characterization of the creep behavior of LPBF 316L, which has been poorly studied and understood to date. The presentation includes results regarding the mechanical properties, the initial microstructural state and its evolution under loading, and the damage mechanism. This work was done within the BAM focus area materials project AGIL. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant was also tested.
T2 - 2nd Workshop on In-situ Monitoring and Microstructure Development in Additive Manufactured alloys at BAM
CY - Online Meeting
DA - 19.04.2021
KW - 316L
KW - Additive Manufacturing
KW - Creep behavior
PY - 2021
AN - OPUS4-52682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Darvishi Kamachali, Reza
T1 - CALPHAD integrated density-based phase diagrams and opening possibilities for grain boundary engineering
N2 - Engineering grain boundaries demands a quantitative description of both their segregation and specific phase behavior. Recently I have proposed a density-based model for grain boundary thermodynamics that enables CALPHAD integrated derivation of grain boundary phase diagrams, broadly applied now in studying various alloys. Combining this model with experimental investigations, in this talk, new aspects of interfacial segregation and phase transformation revealed in polycrystalline alloys are discussed. The effect of elastic interaction on grain boundary phase behavior is incorporated. We consider Al alloys and novel high-entropy alloys and discuss a general strategy for grain boundary engineering.
T2 - 18th Discussion Meeting on Thermodynamics of Alloys (TOFA)
CY - Krakow, Poland
DA - 12.09.2022
KW - CALPHAD
KW - Microstructure Design
KW - Materials Modelling
PY - 2022
AN - OPUS4-56044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - Material Acceleration Platforms of BAM (MAPs@BAM)
N2 - Material Acceleration Platforms (MAPs) represent a transformative approach to the development of resilient and sustainable technology value chains. These platforms can identify candidate chemistries and structures via simulations, and database searches and leverage machine learning-based rapid screening to accelerate the discovery and deployment of novel materials, thereby addressing critical challenges in modern technology sectors.
Incorporating high-fidelity advanced characterization in the early phases of material development is crucial for early de-risking. Advanced characterization techniques, such as X-ray diffraction, advanced electrochemical and spectroscopic techniques provide comprehensive insights into the structural, chemical, and physical properties of materials. Long-term testing further contributes to the de-risking process by evaluating the durability and stability of materials under various environmental and operational conditions.
This presentation will briefly summarize how we address these issues at MAPs@BAM and provide deep-dives on best practices. As the demand for advanced materials continues to grow, MAPs will play an increasingly vital role in driving technological advancements and addressing global challenges.
T2 - FutureLabsLive Basel
CY - Basel, Switzerland
DA - 25.06.2024
KW - MAPs@BAM
PY - 2024
AN - OPUS4-62643
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - Material Acceleration Platforms of BAM (MAPs@BAM)
N2 - Material Acceleration Platforms (MAPs) represent a transformative approach to the development of resilient and sustainable technology value chains. These platforms can identify candidate chemistries and structures via simulations, and database searches and leverage machine learning-based rapid screening to accelerate the discovery and deployment of novel materials, thereby addressing critical challenges in modern technology sectors.
Incorporating high-fidelity advanced characterization in the early phases of material development is crucial for early de-risking. Advanced characterization techniques, such as X-ray diffraction, advanced electrochemical and spectroscopic techniques provide comprehensive insights into the structural, chemical, and physical properties of materials. Long-term testing further contributes to the de-risking process by evaluating the durability and stability of materials under various environmental and operational conditions.
This presentation will briefly summarize how we address these issues at MAPs@BAM and provide deep-dives on best practices. As the demand for advanced materials continues to grow, MAPs will play an increasingly vital role in driving technological advancements and addressing global challenges.
T2 - EERA-JPNM Days Workshop (EERA-Joint Programme on Nuclear Materials)
CY - Online meeting
DA - 29.05.2024
KW - MAPs@BAM
PY - 2024
AN - OPUS4-62642
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - The interplay of anodic passivation and oxygen evolution on multi-principal element alloys (MPEAs)
N2 - Multi-principal element alloys (MPEAs) are of great academic and industrial interest as emerging materials for engineering applications as well as potential electrode materials in energy conversion and storage. Several MPEAs have been studied for their general corrosion behavior, but studies on their dissolution in the high anodic “transpassive” potentials relevant for oxygen evolution reaction (OER) and local corrosion behavior remained scarce.
In this project we have investigated CrMnFeCoNi, FeCrNi and CrCoNi MPEAs in terms of their transpassive behavior in NaCl electrolytes and artificial seawater [1, 2]. We introduced a characterization procedure to distinguish the individual contributions of oxygen evolution reaction (OER) and alloy dissolution [2]. This scheme utilizes scanning electrochemical microscopy (SECM) for detecting the onset of OER and employs quantitative chemical analysis methods, namely inductively coupled mass spectrometry (ICP-MS) and ultraviolet-visible light (UV-Vis) spectroscopy, to elucidate the processes of metal dissolution. In-situ atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM) were used to analyze the corrosion morphology and surface potentials before, during, and after passivity breakdown.
Our results clearly demonstrate the superior corrosion behavior of CrCoNi and FeCrNi MPEA in comparison to the CrFeMnCoNi HEA, as well as AISI 304 stainless steel. We have observed that significant OER occurs in parallel with metal dissolution on the CrCoNi and FeCrNi MPEA surfaces during anodic polarization at potentials relevant to water electrolysis. Most importantly, our findings underscore the necessity of analyzing metal ions dissolved into the electrolyte to accurately assess the Faradaic efficiencies of non-noble metal OER electrocatalysts. The presentation will summarize our characterization procedure and give an overview on the key properties of the studied MPEAs.
[1] A. Wetzel, M. von der Au, P.M. Dietrich, J. Radnik, O. Ozcan, J. Witt, The comparison of the corrosion behavior of the CrCoNi medium entropy alloy and CrMnFeCoNi high entropy alloy, Appl. Surf. Sci., 601 (2022) 154171.
[2] A. Wetzel, D. Morell, M. von der Au, G. Wittstock, O. Ozcan, J. Witt, Transpassive Metal Dissolution vs. Oxygen Evolution Reaction: Implication for Alloy Stability and Electrocatalysis, Angew. Chem. Int. Ed. Engl., n/a (2024) e202317058.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - CCMat
KW - Corrosion
KW - Electrocatalysis
KW - Oxygen evolution reaction
PY - 2024
AN - OPUS4-62637
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Investigation of corrosion behavior of S355 steel in artificial seawater and sediment
N2 - The safe operation of offshore wind turbines places high demands on corrosion protection. This is particularly the case about the planned future extension of the service life beyond 25 years. The highly corrosive environment towards metallic materials leads to a loss of material thickness of the tower structure and thus to a deterioration of mechanical properties. This can be counteracted by corrosion protection measures adapted to the respective load case, such as organic coatings and cathodic corrosion protection (CCP). Much research has already been done in this area about inhibiting the corrosion process and there are regulations and guidelines that specify requirements for corrosion protection to achieve the required service lives.
However, gaps exist regarding free corrosion. This plays a greater role especially for time intervals during the installation of the plants and their maintenance, during which often no CCP can be operated. This applies to the exposure areas in the underwater and sediment area. This problem is intensified by the difficult to estimate corrosion rates caused by the different zones, with their different amounts of dissolved oxygen and the various influencing factors.
This paper deals with experiments conducted in a laboratory container with artificial seawater and sediment in basins.
T2 - AMPP Annual Conference + Expo 2025
CY - Nashville, TN, USA
DA - 07.04.2025
KW - Seawater
KW - Sediment
KW - Corrosion
KW - Offshore
KW - Foundation
KW - Element current
PY - 2025
AN - OPUS4-62964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - State-of-the-art in map development: Best practices for application in nuclear materials
N2 - Material Acceleration Platforms (MAPs) represent a transformative approach to the development of resilient and sustainable technology value chains. These platforms can identify candidate chemistries and structures via simulations, and database searches and leverage machine learning-based rapid screening to accelerate the discovery and deployment of novel materials, thereby addressing critical challenges in modern technology sectors.
Incorporating high-fidelity advanced characterization in the early phases of material development is crucial for early de-risking. Advanced characterization techniques, such as X-ray diffraction, advanced electrochemical and spectroscopic techniques provide comprehensive insights into the structural, chemical, and physical properties of materials. Long-term testing further contributes to the de-risking process by evaluating the durability and stability of materials under various environmental and operational conditions.
This presentation will briefly summarize how we address these issues at MAPs@BAM and provide deep-dives on best practices. As the demand for advanced materials continues to grow, MAPs will play an increasingly vital role in driving technological advancements and addressing global challenges.
T2 - CONNECT-NM European Partnership Kick-off Meeting
CY - Madrid, Spain
DA - 02.10.2024
KW - MAPs@BAM
KW - Corrosion
PY - 2024
AN - OPUS4-62646
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - Material Acceleration Platforms of BAM (MAPs@BAM)
N2 - Material Acceleration Platforms (MAPs) represent a transformative approach to the development of resilient and sustainable technology value chains. These platforms can identify candidate chemistries and structures via simulations, and database searches and leverage machine learning-based rapid screening to accelerate the discovery and deployment of novel materials, thereby addressing critical challenges in modern technology sectors.
Incorporating high-fidelity advanced characterization in the early phases of material development is crucial for early de-risking. Advanced characterization techniques, such as X-ray diffraction, advanced electrochemical and spectroscopic techniques provide comprehensive insights into the structural, chemical, and physical properties of materials. Long-term testing further contributes to the de-risking process by evaluating the durability and stability of materials under various environmental and operational conditions.
This presentation will briefly summarize how we address these issues at MAPs@BAM and provide deep-dives on best practices. As the demand for advanced materials continues to grow, MAPs will play an increasingly vital role in driving technological advancements and addressing global challenges.
T2 - International Cooperation on Innovative Materials for Energy Workshop
CY - Brussels, Belgium
DA - 19.04.2024
KW - MAPs@BAM
PY - 2024
AN - OPUS4-62641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Saber, Yassin
T1 - Fully Automated 3D Printing of Ceramics for Remote and Decentralized Manufacturing
N2 - Manufacturing high-performance ceramic components in remote or decentralized environments – such as in the field, on maritime missions or on isolated offshore platforms – requires solutions that are reliable, low-maintenance, and easy to operate. We present a novel end-to-end manufacturing system designed to produce dense, functional, and geometrically complex ceramic parts using Fused Filament Fabrication (FFF) with minimal human intervention. Our system enables the automated production of yttria-stabilized zirconia (YSZ) components by integrating printing, debinding, and sintering into one streamlined process and thus eliminating the need for multiple specialized machines. Our system combines a dual extrusion filament printer with a porous and heat-resistant ceramic print bed. The porous print bed allows for mechanical interlocking of the first printed layers, ensuring adhesion and structural integrity during FFF. YSZ components are printed onto sacrificial polylactide (PLA) rafts, which serve as a temporary foundation. Once printing is finished, a furnace unit is seamlessly lowered, enclosing the green parts for debinding, and sintering. During firing the PLA raft is disintegrated, enabling unconstrained sintering and easy final part removal. In conclusion, our integrated solution enables localized, on demand fabrication of geometrically complex ceramic components in remote environments with increased efficiency and minimal human handling.
T2 - Ceramic AM Summit 2025
CY - Berlin, Germany
DA - 30.06.2025
KW - Fused Filament Fabrication
KW - Ceramics
KW - Metalls
KW - Process automation
PY - 2025
AN - OPUS4-63623
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Nina
A1 - Uhlig, Marvin
A1 - Kromm, Arne
A1 - Schröpfer, Dirk
A1 - Höfer, Kevin
A1 - Hensel, Jonas
A1 - Kannengießer, Thomas
T1 - Challenges in the evaluation of the weldability of old mild steels for future use
N2 - For reasons of sustainability and cost efficiency, there is an increasing trend in the steel-processing industry to retrofit existing structures, avoiding costly shutdowns or dismantling. Although welding is a cost-effective joining method, it is rarely applied to old steels, whereas riveted or bolted connections are often uneconomical. Repair and refurbishment frequently require the replacement of damaged material or the creation of dissimilar old–new steel joints. Due to the varied manufacturing processes of historical steels, not all twentieth-century steels are inherently weldable, making an initial assessment of weldability
essential. In this study, a historical non-deoxidized mild steel (produced by Siemens–Martin processing) originating from the construction of the Berlin Radio Tower (erected in 1926) was investigated using dilatometry to analyze its welding behavior. A database of welding CCT diagrams and HAZ simulations was established to support practice-oriented welding experiments, providing key insights into their weld-metallurgical behavior and weldability. Furthermore, initial welding trials were conducted, and the local residual stress states in dissimilar old–new steel joints were determined. These foundational investigations are critical for the development of innovative, load-adapted welding concepts for the repair and refurbishment of existing old-steel infrastructure in Germany.
KW - Old mild steels
KW - Repair welding
KW - Weldability
KW - Thermo-physical simulation
KW - CCT diagrams
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654784
DO - https://doi.org/10.1007/s40194-026-02366-6
SN - 1878-6669
SP - 1
EP - 14
PB - Springer nature
AN - OPUS4-65478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oskoei, Párástu
A1 - Afonso, Rúben
A1 - Bastos, Verónica
A1 - Nogueira, João
A1 - Keller, Lisa-Marie
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Daniel-da-Silva, Ana L.
A1 - Oliveira, Helena
T1 - Upconversion Nanoparticles with Mesoporous Silica Coatings for Doxorubicin Targeted Delivery to Melanoma Cells
N2 - Melanoma is one of the most aggressive skin cancers and requires innovative therapeutic strategies to overcome the limitations of conventional therapies. In this work, upconversion nanoparticles coated with mesoporous silica and functionalized with folic acid (UCNP@mSiO2-FA) were developed as a targeted nanocarrier system for the delivery of doxorubicin (DOX). The UCNPs were synthesized via thermal decomposition, coated with mesoporous silica shells, and functionalized with folic acid (FA) to enable receptor-mediated targeting. DOX was then loaded into the mesoporous silica coating by adsorption, yielding UCNP@mSiO2-FA-DOX. The different UCNPs were characterized for size, composition, colloidal stability, and loading and release of DOX. This comprehensive physicochemical characterization confirmed a high DOX loading efficiency and a slightly increased drug release under acidic conditions, mimicking the tumour microenvironment. In vitro assays using four melanoma cell lines (A375, B16-F10, MNT-1, and SK-MEL-28) revealed an excellent biocompatibility of UCNP@mSiO2-FA and a significantly higher cytotoxicity of UCNP@mSiO2-FA-DOX compared to unloaded UCNPs, in a dose-dependent manner. Cell cycle analysis demonstrated G2/M phase arrest after treatment with UCNP@mSiO2-FA-DOX, confirming its antiproliferative effect. Overall, UCNP@mSiO2-FA-DOX represents a promising nanoplatform for targeted melanoma therapy, combining active tumour targeting and enhanced anticancer efficacy.
KW - Fluorescence
KW - Synthesis
KW - Nano
KW - Particle
KW - Silica
KW - Cell
KW - Uptake
KW - Drug
KW - Characterization
KW - DOX
KW - Imaging
KW - Toxicity
KW - Release
KW - pH
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653596
DO - https://doi.org/10.3390/molecules31010074
SN - 1420-3049
VL - 31
IS - 1
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-65359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
A1 - Keserović, A.
A1 - Sobetzki, J.
A1 - Sarmiento-Klapper, H.
A1 - Boduch, A.
A1 - Aristia, G.
A1 - Faes, W.
A1 - Stoljarova, A.
A1 - Zimmer, S.
T1 - Metallene Werkstoffe in Geothermieanlagen - nicht nur aus Sicht der Korrosion
N2 - Um Konstrukteuren und Nutzern geothermischer Anlagen grundlegende Informationen über die Korrosionsbeständigkeit zur Verfügung zu stellen, wurden verschiedene metallene Werkstoffe, darunter nichtrostende Duplex- und austenitische Stähle sowie eine Nickellegierung, in künstlichen Geothermalwässern, die die Bedingungen an verschiedenen Standorten mit geothermischem Potenzial simulieren, mit Hilfe von elektrochemischen und Langzeittests hinsichtlich ihrer Eignung bewertet.
In hochsalinaren Umgebungen erwies sich Spaltkorrosion als der entscheidende Mechanismus. Die Nickellegierung zeigt eine ausgezeichnete Beständigkeit gegenüber Lochkorrosion. Abgesehen von ihren hohen Kosten eignet sie sich sehr gut für den Bau von Geothermieanlagen mit stark salzhaltigen Fluiden. Rostfreie Stähle und Duplexstähle weisen eine begrenzte Korrosionsbeständigkeit gegen Loch- und Spaltkorrosion auf. Daher sind sie für stark salzhaltige Fluide nicht geeignet. Der Superaustenit zeigt ein temperaturabhängiges Verhalten. In nichtsalinaren Umgebungen könnten niedriglegierte Stähle (neben den höherlegierten Werkstoffen) als Konstruktionsmaterial für Geothermieanlagen eingesetzt werden, sofern eine ausreichende Wandstärke des Materials berücksichtigt wird.
Neben Korrosionsaspekten erwies sich auch die Ausfällung von Fluidbestandteilen als interessantes Thema. Beim Betrieb der Forschungsanlage in Groß Schönebeck wurden Kupfer- und Bleieffekte im Bohrloch festgestellt. Die auftretenden Mechanismen und Maßnahmen zur Verhinderung von Ausfällungen und Abscheidungen wurden ebenso untersucht, wie deren mögliche Einflüsse auf die Korrosionsbeständigkeit metallener Werkstoffe für Anlagenkomponenten.
Der Beitrag beschreibt die Wechselwirkungen zwischen Geothermalwässern und Ausrüstungskomponenten.
T2 - 57. Kraftwerktechnisches Kolloquium
CY - Dresden, Germany
DA - 07.10.2025
KW - Örtliche Korrosion
KW - Edelstahl
KW - Ni-Legierungen
KW - Geothermie
KW - Abscheidung
PY - 2025
SN - 978-3-00-082651-1
SN - 978-3-00-082652-8
SP - 551
EP - 568
PB - IKS-Verlag
CY - Freiberg
AN - OPUS4-64320
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quosdorf, Heike
T1 - Digital object identifier for additively manufactured parts based on 3D microstructural information
N2 - Additive manufacturing (AM) is rapidly emerging from prototyping to industrial production [1]. Thus, providing AM parts with a tagging feature that allows unambiguous identification, can be crucial for logistics, certification, and anti-counterfeiting purposes. The digital object identifier (DOI) acts like a fingerprint for the product throughout its entire lifecycle. Several methods are already available, which range from encasing a detector [2] to leveraging the stochastic defects of AM parts [3], printing a quick response (QR) code or a set of voids partially filled with loose powder within the part [3]. A new method is using microstructural features of the AM part without altering their properties. This technology transfer project aims to implement this authentication methode as software solution to act as certificate in the Digital Product Passport (DPP) [5].
T2 - QI Digital 2025
CY - Berlin, Germany
DA - 08.10.2025
KW - Authentication
KW - Unique identification
KW - Open Science, Material Digital
KW - Digital fingerprint
KW - Open Source Software
KW - X-ray Computed Tomography
KW - Additive manufacturing
PY - 2025
AN - OPUS4-65207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Entwicklung einer Prüfmethode zur Bewertung der Materialbeständigkeit von Bauteilen in Mitteldestillatanwendungen
N2 - Im DGMK-Projekt 780 wurde eine forcierte Prüfmethode entwickelt zur Bestimmung der Beständigkeit von metallenen Werkstoffen gegenüber Brennstoffen aus Mitteldestillaten und Gemischen aus Mitteldestillat und paraffinischen Kohlenwasserstoffen, die jeweils Fettsäuremethylester (FAME) als biogene Komponente enthalten. Bei der Prüfmethode werden Proben des Werkstoffes in einem speziellen Prüfmedien ausgelagert. Die Zusammensetzung von zwei Prüfmedien wurde im Vorhaben erarbeitet. Die Prüfmedien decken für den FAME-Anteil einen Bereich von bis zu 20 % (V/V) ab. Die Auslagerung kann bei geringem Aufwand unter Atmosphärendruck durchgeführt werden.
Die Eignung einer Auswahl von metallenen Werkstoffen und Polymerwerkstoffen, die für Versorgungsanlagen für Mitteldestillat relevant sind, wurde durch Auslagerung in folgenden nicht gealterten Brennstoffen bestimmt: Heizöl EL schwefelarm (B0), Heizöl EL schwefelarm mit 20 % (V/V) FAME (B20), FAME (B100) und hydriertes Pflanzenöl (HVO). Die Temperatur bei der Auslagerung betrug 50 °C für die metallenen Werkstoffe und 40 °C und 70 °C für die Polymerwerkstoffe. Die Ergebnisse der Beständigkeitsbewertung wurden in Beständigkeitslisten zusammengefasst. Die mit dem B20 erhaltenen Werkstoffbeständigkeiten gelten generell für Gemische aus Heizöl EL schwefelarm und FAME mit einem FAME-Gehalt bis zu 20 % (V/V). Sie sind auch auf Gemische aus Dieselkraftstoff und FAME mit einem FAME-Gehalt bis 20 %(V/V) übertragbar.
Die forcierte Prüfmethode kann insbesondere KMUs bei der Weiterentwicklung von bestehenden Produkten und der Entwicklung von neuen Produkten als ein kostengünstiger Schnelltest zur Überprüfung der Werkstoff- und Bauteilbeständigkeit gegenüber Mitteldestillaten mit hohem FAME-Anteil dienen. Sie kann für die Hersteller die Sicherheit erhöhen, dass Bauteile die Freigabeprüfungen der Bauaufsicht bestehen, wobei die Freigabe aber nur für Deutschland gültig ist.
Die Erkenntnisse des Forschungsvorhabens können in eine harmonisierte Europäischen Norm für alternative Brenn- und Kraftstoffe einfließen. Diese ist für die Bauteilhersteller die Voraussetzung für die Erschließung des europäischen Marktes.
T2 - Sitzung des DGMK-Fachausschusses "Brennstoffe"
CY - Online Meeting
DA - 22.09.2020
KW - Korrosion
KW - Biobrennstoff
KW - Heizöl
KW - FAME
PY - 2020
AN - OPUS4-51300
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aristia, Gabriela
A1 - Bäßler, Ralph
A1 - Nofz, Marianne
A1 - Sojref, Regine
A1 - Kohl, Anka
T1 - Short-term exposure tests of ɣ-Al2O3 Sol-gel coating on X20Cr13 in artificial geothermal waters with different pH
N2 - The suitability of an Al2O3 coating for corrosion protection on X20Cr13 was evaluated in various artificial geothermal brines, focusing on the influence of different pH (4, 6 and 8) and their chemical compositions on the coating properties. All experiments were performed in the laboratory using autoclaves at 150 ◦C and 1 MPa in deaerated condition for 1 and 7 days. Results showed that the pH of geothermal waters is the most detrimental factor in the transformation of ɣ-Al2O3 and its protective abilities. Delaminations were found in the Coating exposed to geothermal brines with pH 4. FTIR spectra indicated a transformation of ɣ-Al2O3 to boehmite AlOOH after exposure to pH 4 and 6, and bayerite Al(OH)3 was formed after exposure to pH 8. Different Crystal structures of the hydrated Al2O3 also contribute to the stability of the coatings, observed by the SEM- EDX of the surface and cross-section of coatings. This study indicated that ɣ-Al2O3 sol-gel coating presents a promising aspect of corrosion protection in geothermal environment with a neutral pH.
KW - Al2O3
KW - Corrosion
KW - Coating
KW - Martensitic steel
PY - 2021
DO - https://doi.org/10.1016/j.geothermics.2021.102193
SN - 0375-6505
VL - 96
SP - 102193
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-52931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - Autonomous exploration of new alloy chemistries using a Material Acceleration Platform (MAP)
N2 - The discovery and commercialization of new corrosion resistant alloys by conventional approaches and manual experimentation is a slow and expensive process. In the last few years, efforts have been dedicated internationally to design self-driving-laboratories, also called Material Acceleration Platforms (MAPs). MAPs integrate material synthesis, characterization and testing modules into circular workflows through automation and use artificial intelligence (AI) for efficient and autonomous experiment design, property prediction and data analysis.
We have established a MAP for corrosion research by automating diverse liquid operations, electrochemical testing and data evaluation, where the test results are interpreted via a machine learning (ML)-based backend. The workflows of the electrochemistry module are configured for electrodeposition of different alloys and subsequently performing electrochemical corrosion testing. The platform uses the results of the electrochemical tests to determine the next set of deposition parameters in a continuous and autonomous loop until the user-defined objectives are met.
In this project we used the MAP to design new multi-principal element alloys (MPEAs) as corrosion resistant electrode materials for H2O and CO2 electrolysis. One campaign contains a maximum of 144 runs. From each successful campaign top five leads and another five randomly selected materials proceed to upscaling either by electrodeposition at larger scale or as bulk ingots cast by means of arc-melting. With these samples, a detailed chemical and electrochemical characterization using surface analysis techniques was performed to validate the success of the MAP-based optimization. The presentation will give an overview of the design and build phases of our MAP, its modules and workflows. Moreover, we will summarize our results from the FeNiCrCuCoMo MPEA system.
T2 - EUROCORR 2024
CY - Paris, France
DA - 01.09.2024
KW - MAPs@BAM
KW - Corrosion
KW - Electrodeposition
KW - Material Acceleration Platform
KW - Electrochemistry
PY - 2024
AN - OPUS4-62635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
T1 - Pulverbasierte additive Fertigung unter reduzierten Schwerkraftbedingungen
N2 - 2014 wurden die ersten additiv gefertigten Bauteile in der Internationalen Raumstation (ISS) hergestellt. Die Ära des 3D Drucks im Weltraum startete bereits 2010 mit einem NASA Projekt. Made in Space Inc. entwickelte im Auftrag der NASA einen 3D Drucker auf Basis der Fused Deposition Modeling (FDM) Technologie. Seit 2016 gibt es in der ISS eine Additive Manufacturing Facility und seitdem wurden mittels FDM mehr als hundert Teile aus Kunststoff 3D gedruckt. Die ESA arbeitet gleichfalls an der Entwicklung eines FDM-3D Druckers für die Schwerelosigkeit, z.B. im ESA Projekt „IMPERIAL“, „MELT 3D printer“. Metallische Bauteile mit guten mechanischen Eigenschaften und guter Genauigkeit können kommerziell mittels des Laserstrahlschmelzens (Laser Powder Bed Fusion LPBF) dargestellt werden. Diese Technologie kann allerdings im Weltraum nur unter der Voraussetzung angewendet werden, dass das Pulvermaterial in der Schwerelosigkeit manipuliert und in Form einer dünnen Schicht stabilisiert werden kann. Standard LBM-Anlagen sind deshalb für einen Betrieb in Schwerelosigkeit nicht geeignet, was z.B. auch von Made in Space Inc. in der Vergangenheit beleuchtet wurde. Die pulverbasierte additive Fertigung unter Schwerelosigkeit erfordert die Entwicklung völlig neuartiger Technologien zum Schichtauftrag.
Methoden:
Mit Hilfe der „Gasflussunterstützten Pulverdeposition“ wurden im Rahmen des Projekts unter reduzierter Schwerkraft systematische Parameterstudien zum LPBF-Prozess durchgeführt. Das Projekt knüpfte an erfolgreiche Vorarbeiten zur Gasflussunterstützten Pulverdeposition unter µg Bedingungen aus vier DLR Parabelflugkampagnen (30., 31., 33. und 34.) an.
Ergebnisse:
In den Parabelflugkampagnen 76 der ESA und 38 des DLR wurde eine neue Einheit in Wabenform für den Schichtauftrag von Pulver getestet. Es konnte gezeigt werden, dass diese Einheit, die auch als Pulverreservoir funktionierte und mittels eines Aktuators in Schwingungen versetzt wurde, einen reproduzierbaren Schichtauftrag mit geringem Pulververlust unter Schwerelosigkeit ermöglicht. Um die Qualität der aufgetragenen Schicht überwachen zu können, wurde ein Linienscanner beschafft und in die Anlage integriert. Mit diesem kann ein 3D Profil der Schichten im laufenden Prozess erstellt werden, was eine Qualitätskontrolle jeder einzelnen Schicht im Prozess erlaubt. Neben Edelstahl (316L) wurde das Schmelzverhalten von Regolith direkt im Pulverbett unter Bedingungen reduzierter Schwerkraft ebenfalls untersucht. Ein Modell zum Verständnis der Einflussgrößen Gravitation, Schmelzbadgröße, Partikelgröße und Zusammensetzung des Regolith wurde entwickelt.
Schlussfolgerungen:
Die Entwicklung einer leistungsfähigen Rakeleinheit für den Schichtauftrag unter Schwerelosigkeit ist Voraussetzung für die Generierung defektfreier Bauteile in der pulverbasierten additiven Fertigung in Schwerelosigkeit. Der Übergang zum Werkstoff Regolith hat die Thematik der Verwendung von lokalen Rohstoffen (ISRU), z.B. Mondstaub auf dem Mond, in Kombination mit dem Ziel einer hohen Produktivität beim Aufbau großer Strukturen hervorgebracht. Hierbei ist das Thema einer handhabbaren Schmelzpoolgröße im Laserschmelzprozess unter variierender Schwerkraft in den Fokus gerückt und wird derzeit noch beforscht.
T2 - DLR Statussymposium
CY - Bonn, Germany
DA - 12.03.2025
KW - Regolith
KW - Mond
KW - ISRU
KW - micro-g
PY - 2025
AN - OPUS4-63964
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Determination of Corrosivity: Approach according to UN Regulations
N2 - “Corrosive to Metals” (H290) describes the general potential danger of a substance to metallic materials. Uniform and localized attack is considered. It has nothing to do with containment material. Corrosion resistance of materials is determined similarly, but with much lower threshold values.
Manual shall provide a simple test to easily determine the aggressivity potential to cause corrosion on metallic materials.
Even a simple test requires experienced personnel. There seems to be a need of awareness and understanding training for both officials and applicants.
T2 - ECHA GHS Training
CY - Online meeting
DA - 16.03.2021
KW - Corrosivity
KW - Dangerous good
KW - Corrosion
PY - 2021
AN - OPUS4-52295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pötzsch, Sina
A1 - Weltschev, Margit
A1 - Bäßler, Ralph
T1 - Compatibility of polymers exposed to heating oil blends with 10 % and 20 % biodiesel (FAME)
N2 - Biodiesel (FAME) from rapeseed is an environmentally friendly alternative to common fossil fuels. It is also suitable to serve as blending component to fuels like heating oil. If the fuel composition is changed, materials compatibility must be guaranteed. Adding polar biodiesel to nonpolar heating oil, changes the blend’s solvency and might cause swelling, extraction and solvation of polymers. The objective of this research was to investigate the compatibility of polymeric materials, which are commonly used for components in middle distillate facilities, along with blends of heating oil and 20 % biodiesel (B20). For this propose, ACM, HNBR, FKM, PE, PA 6, POM, PUR and PVC were exposed to heating oil and B20 for 42 and 84 days at 40 °C. In addition, the polymers HNBR, FKM, PA, POM and PVC were also exposed at 70 °C. Furthermore, the resistance of polymers in eight-year aged B10 at 40 °C was evaluated. Ageing of biodiesel increases acidity which might propagate polymer corrosion. The materials were evaluated as resistant, if the loss in tensile properties (tensile strength and elongation at break) and Shore hardness remained under 15 % compared to the initial unexposed material values. For investigations under compressed conditions, the compression set was determined for specimens of ACM, FKM and HNBR after exposure in heating oil B0 and B20 for 3,7,14, 28, 56 and 90 days at 40 °C according to ISO 815-1. It was found that the resistance in B20 at 40 °C was given for all tested polymers except PUR. In the 8 years aged B10, PUR and POM were not compatible and ACM just conditionally compatible. At 70 °C, FKM and PVC were resistant in B20, whereas HNBR and PA 6 were not compatible. Swelling occurred for the elastomers ACM, HNBR and PUR.
T2 - AMPP Annual International Corrosion Conference 2021
CY - Online Meeting
DA - 19.04.2021
KW - Biodiesel
KW - FAME
KW - RME
KW - Polymer in fuels
PY - 2021
SP - 16222-01
EP - 16222-12
CY - Houston
AN - OPUS4-52499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Components in CO2-stream, corrosive to Materials to be Used in CC(U)S Applications
N2 - CO2 quality specifications are not only a matter of CO2 purity (i.e. CO2 content).
The “rest” also matters, in particular contents of reactive impurities affecting material corrosion (and rock alteration).
Also chemical reactions in CO2 stream needs to be considered, in particular when combining CO2 streams of different compositions.
T2 - WCO Forum at AMPP Annual International Corrosion Conference 2021
CY - Online Meeting
DA - 26.04.2021
KW - Carbon capture storage
KW - Corrosion
PY - 2021
AN - OPUS4-52502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Influence of Precipitating Brine Components on Materials Selection for Geothermal Applications
N2 - By exposure and electrochemical tests in the laboratory the Cu- and Pb-effect on corrosion behavior and performance of carbon steel and a corrosion resistant alloy could be assessed. Critical material specific properties were determined by static exposure and electrochemical tests in artificial geothermal water with high salinity and low pH, containing Cu/Pb.
It could be shown that significant Cu- resp. Pb-deposition and precipitation only occurred in combination with carbon steel. Corrosion resistant alloys (e. g. Cr- and Ni-dominated stainless steels) prevent the disturbing Cu-agglomeration resp. Pb-deposition. Therefore, they are suitable to be chosen for future design of geothermal piping system, either in massive or in cladded form. Regarding corrosion, formation of crevices with non-metallic materials shall be avoided.
So, in addition to its already known limited corrosion resistance, carbon steel shall not be used when copper or lead species are content of the geothermal brine. Otherwise precipitation and/or deposition of metallic copper resp. lead must be expected, increasing the susceptibility of clogging the piping system.
From the interactions and pitting corrosion point of view, corrosion resistant alloys (preferably Ni-rich) seem to be most favorable when selecting materials for applications in such geothermal brines.
T2 - World Geothermal Congress
CY - Online meeting
DA - 15.06.2021
KW - Copper
KW - Lead
KW - Corrosion
KW - Steel
KW - Geothermal energy
PY - 2021
AN - OPUS4-52829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Solomun, Tihomir
A1 - Hahn, Marc Benjamin
A1 - Smiatek, J.
T1 - Raman spectroscopic signature of ectoine conformations in bulk solution and crystalline state
N2 - Recent crystallographic results revealed conformational changes of zwitterionic ectoine upon hydration. By means of confocal Raman spectroscopy and density functional theory calculations, we present a detailed study of this transformation process as part of a Fermi resonance analysis. The corresponding findings highlight that all resonant couplings are lifted upon exposure to water vapor as a consequence of molecular binding processes. The importance of the involved molecular groups for water binding and conformational changes upon hydration is discussed. Our approach further Shows that the underlying rapid process can be reversed by carbon dioxide saturated atmospheres. For the first time, we also confirm that the conformational state of ectoine in aqueous bulk solution coincides with crystalline ectoine in its dihydrate state, thereby highlighting the important role of a few bound water molecules.
KW - Fermi resonance
KW - Ectoine hydration
KW - DFT calculations of Raman spectra
KW - Position of carboxylate group
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509855
DO - https://doi.org/10.1002/cphc.202000457
SN - 1439-4235
SN - 1439-7641
VL - 21
IS - 17
SP - 1945
EP - 1950
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-50985
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
A1 - Stoljarova, A.
A1 - Regenspurg, S.
T1 - Influence Of Brine Precipitates On Materials Performance In Geothermal Applications
N2 - Since geothermal wells are a feasible energy source to replace fossil fuel supply, many technologies have been developed to take advantage of geothermal energy. Nevertheless, service conditions in geothermal facilities are in many cases extreme in terms of corrosion due to the chemical composition of hydrothermal fluids and temperatures. Therefore, materials selection based on preliminary material qualification is essential to guarantee a secure and reliable operation of the facilities. During operation of a geothermal research facility in Groß Schönebeck copper and lead effects have been found downhole. Occurring mechanisms and measures to prevent precipitation or scaling needed to be investigated as well as potential influences of such precipitates on corrosion resistance of metallic materials used for equipment.
This contribution deals with the evaluation of the corrosion behavior of carbon steel and corrosion resistant alloys in copper and/or lead containing artificial geothermal water, simulating the conditions in the Northern German Basin.
The behavior of these materials in an artificial geothermal water obtained by electrochemical measurements and exposure tests are presented. While carbon steel exhibits precipitation and deposition, higher alloyed material shows different response to such species and a higher resistance in saline geothermal water.
Basing on these results the suitability of the investigated corrosion resistant alloy is given for use in such conditions, whereas carbon steel creates difficulties due to its susceptibility to Cu- and Pb-precipitation.
T2 - AMPP Annual 2023 Conference
CY - Denver, CO, USA
DA - 19.03.2023
KW - Geothermal
KW - Electrochemistry
KW - Copper
KW - Lead
KW - Corrosion
PY - 2023
SP - 1
EP - 15
PB - AMPP
CY - Houston TX USA
AN - OPUS4-57233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wetzel, Annica
T1 - Corrosion Properties and Protective Oxide Film Characteristics of CrMnFeCoNi High Entropy Alloy and CrCoNi Medium Entropy Alloy
N2 - High and medium entropy alloys gained increasing academic and industrial interest as novel materials for engineering applications. This project is aiming to clarify and compare the general and local corrosion properties of high entropy alloy CrMnFeCoNi and medium entropy alloy CrCoNi in different aqueous environments. The focus lies on the local corrosion processes that result either from microstructural imperfections (inclusions, defects at grain boundaries etc.) in the base material or processing related changes in the microstructure and/or local composition.
The corrosion behavior of the alloys was monitored via potentiodynamic polarization experiments and the local corrosion characteristics were further investigated by means of scanning electrochemical microscopy (SECM). Their passivation behavior was analyzed in two different electrolyte systems (NaCl and H2SO4 c = 0.1M). The characterization of the surface morphology and composition of the passive film was performed by means of atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-Ray spectroscopy (SEM/EDX) and X-Ray photoelectron spectroscopy (XPS), respectively. To analyze the semiconducting properties of the passive film Mott-Schottky analysis was conducted.
Considering long term corrosion effects, electrochemical work was supported with immersion tests and the analysis of corrosion products by SEM/EDX, ICP-MS and XPS depth-profiling. Our results indicate that the medium entropy alloy CrCoNi has a significantly higher corrosion resistance due to the higher concentration of chromium in comparison to the high entropy alloy CrMnFeCoNi. The presentation will summarize our results on the mechanistical aspects of the observed high corrosion resistance.
T2 - ISE Annual 72nd meeting
CY - Online meeting
DA - 29.08.2021
KW - High Entropy Alloys
KW - Aqueous Corrosion
KW - Medium Entropy Alloys
KW - Atomic Forc Microscopy
KW - Scanning Kelvin Probe Force Microscopy
KW - Potentiodynamic Polarization
KW - Electrochemical Impedance Spectroscopy
KW - ICP-MS
PY - 2021
AN - OPUS4-53789
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Stohl, Leonie
T1 - MI Funktionsbeton: Funktionalisierte Betonoberflächen zur gezielten Einstellung der Biorezeptivität
N2 - Beschreibung des Projektes MI Funktionsbeton 1462, Update nach 15 Monaten.
Der Bericht umfasst Hintergrund, Projektzeitplan und aktuellen Stand.
KW - Biorezeptivität
KW - Beton
KW - Biofilm
KW - Struktur
PY - 2022
SP - 1
EP - 13
AN - OPUS4-58376
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yesilcicek, Yasemin
T1 - Corrosion and mechanical properties of multi principal element alloys designed by using diffusion couples
N2 - The efficient exploration of novel alloy chemistries is crucial for advancing the development of new materials. Diffusion-controlled synthesis of gradient alloys is an intelligent approach for creating phase diagrams and to effectively identify potential material combinations with tailored properties.
This project focusses on the design of quaternary multi-principle-element alloys (MPEAs) using diffusion couples. Our diffusion system contains an equimolar ternary alloy (FeNiCr) and additional single diffusing elements e.g. Mn and Mo. We determined the optimal temperature ranges for the diffusion thermal treatment by means of ThermoCalc simulations with the aim to form single-phase MPEAs. Microstructure and chemical characterization of the diffusion couples were performed by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). For most alloy couples, the diffusion zone contained a single-phase alloy matrix with diffusion-induced compositional gradient as well as precipitation phases. This heterogeneity makes the diffusion couples interesting materials to investigate local mechanical and corrosion properties. Thus, local corrosion properties were examined using Atomic Force Microscopy (AFM) and Scanning Electrochemical Microscopy (SECM). Nanoindentation was used for the analysis of local mechanical properties.
Based on the results of the local corrosion analysis, we have selected single-phase alloy chemistries along the diffusion zone and reproducibly synthesized these alloys in bulk for detailed corrosion studies by means of potentiodynamic polarization and SECM.
The presentation will briefly summarize our methodology and motivation for using diffusion couples as an efficient tool for exploring phase diagrams of MPEAs in the search for new alloy chemistries and the results of our correlative study on the mechanical and corrosion properties of these materials.
T2 - 244th ECS Meeting
CY - Gothenburg, Sweden
DA - 08.10.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Corrosion
PY - 2023
AN - OPUS4-59407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yesilcicek, Yasemin
T1 - Investigation on gradient Fe-Ni-Cr-Mn alloy using diffusion multiples
N2 - The high-throughput synthesis and characterization of potential material combinations plays an important role in accelerating the development of new materials. Diffusion controlled synthesis of gradient alloys is widely used to create phase diagrams, and it is also one of the most effective combinatorial approaches for rapid realization of potential material combinations.
This study focuses on the synthesis and investigation of the quaternary multi-principle-element alloy (MPEA) FeNiCrMn by means of diffusion multiples, the correlation of their microstructural and chemical characterization data with their application relevant properties like local mechanical and corrosion properties. A diffusion system was set up by combining an equimolar ternary alloy (FeNiCr) with a single diffusing metallic component (Mn) with the highest interdiffusion coefficient. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to collect microstructural and compositional information which were correlated to local mechanical properties studied with nanoindentation. Local corrosion properties were investigated by means of Atomic Force Microscopy (AFM) and Scanning Electrochemical Microscopy (SECM). We have observed that a >50 μm deep homogeneous diffusion zone was formed the thickness of which scales with the duration of the thermal treatment. Beyond the Mn-concentration gradient in the FeNiCr matrix, a distinct Cr-rich secondary phase, characterized by high hardness and elastic modulus values appeared. We synthesized MPEAs with selected compositions from the diffusion zone as well as the Cr-rich phase as bulk alloys for electrochemical corrosion studies under different environmental conditions. The presentation will summarize the results of our correlative study on the mechanical properties and corrosion resistance of the quaternary multi-principle-element alloy (MPEA) FeNiCrMn family.
T2 - MRS Spring 2023
CY - San Francisco, California, USA
DA - 10.04.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Diffusion multiples
PY - 2023
AN - OPUS4-59404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yesilcicek, Yasemin
T1 - Correlation of corrosion and mechanical properties of Fe-Ni-Cr-Mn alloy synthesized by diffusion multiples
N2 - The efficient exploration of novel alloy compositions is crucial for advancing the development of new materials. One widely utilized approach for creating phase diagrams is the use of diffusion-controlled synthesis for gradient alloys. This method is also an effective means for rapidly identifying potential material combinations.
The present study focusses on the exploration of quaternary multi-principle-element alloys (MPEAs) using diffusion multiples. We established a diffusion system by combining an equimolar ternary alloy (FeNiCr) with single diffusing elements Mn and Mo. Using ThermoCalc simulations, we determined suitable temperature ranges where we can expect the formation of single-phase alloys. Depending on the diffusion constants of the selected metals, diffusion times were adjusted to obtain diffusion zones with a depth of greater than 50 μm. Microstructural and compositional information was gathered via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) and correlated to local mechanical properties evaluated by means of nanoindentation. Local corrosion properties were examined using Atomic Force Microscopy (AFM) and Scanning Electrochemical Microscopy (SECM).
Our results indicate that the ThermoCalc simulations have a good predictive power for crystallographic phases. However, especially with the Mn-FeNiCr system, formation of Cr-rich secondary phases were observed, which led to Cr-depletion and thus to localized corrosion processes in the matrix at the vicinity of the secondary phases. Based on the results of the local electrochemical tests, we have selected single-phase compositions along the diffusion zone and synthesized these alloys in bulk for corrosion studies by means of potentiodynamic polarization and SECM.
The presentation will summarize our methodology using diffusion couples as an
efficient tool for exploring compositional spaces of MPEAs in the search for novel single-phase alloys and the results of our correlative study on the mechanical and corrosion properties of these materials.
T2 - EUROCORR2023
CY - Brussels, Belgium
DA - 27.08.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Corrosion
PY - 2023
AN - OPUS4-59408
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wetzel, Annica
T1 - Old materials, new life: Using diffusion-controlled synthesis for discovery of novel alloy systems
N2 - Multi principal element alloy (MPEAs) concept allows us to rethink how we develop application-tailored, sustainable materials. The vast composition space leads to nearly indefinite material combinations and will facilitate finding Pareto optimal materials with lower CO2 footprint and avoidance of critical minerals as design criteria. To probe this large compositional space efficiently, the use high-throughput screening methods is inevitable. Diffusion-controlled synthesis of gradient materials is the optimal technique for screening complex compositional materials that would otherwise require comprehensive modelling or experimental efforts.
In this study, we have used a series of diffusion couples of pure metals and alloys with the aim to create a materials library with correlated data on composition and microstructure. With future recycling prospects in mind, and possible applications of Cu containing alloys in electrocatalytic carbon dioxide reduction and antimicrobial alloys we have generated diffusion couples of brass (Cu63Zn37) and bronze (Cu89Sn11) with either pure metals (Fe, Ni, etc.) or with binary or ternary alloys (FeNi, FeNiCr etc.). For different diffusion times and temperatures, we calculated diffusion constants for the material combinations. Following a detailed characterisation of the gradient materials, we have investigated general and local corrosion properties, electrocatalytic activity for oxygen evolution reaction (OER) and carbon dioxide reduction reaction (CRR) as well as mechanical properties (hardness, elastic modulus) on single-phase alloys synthesized in bulk by means of vacuum arc-melting based on the selected local compositions.
In most cases, due to the short diffusion times, the contact between the diffusion couples lead to two separate diffusion zones and thus, different alloy families on both sides. Especially with ternary alloys, interesting selective diffusion processes and unexpected repulsion effects were observed. The presentation will provide an overview of the gradient materials with a focus on the functional properties of single-phase alloy families derived from them.
T2 - MRS Spring 2023
CY - San Francisco, California, USA
DA - 10.04.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Corrosion
KW - Electrocatalysis
PY - 2023
AN - OPUS4-59406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sediqi, Salmin
T1 - Multi-principal element alloy nanoparticle (MPEA-NP) electrocatalysts prepared by pulsed laser ablation for electroreduction of CO2
N2 - The motivation and overall objective of the project are to develop electrocatalysts that are free of noble metals (e.g., Pt or Au) and are instead based on medium and high entropy alloys (MEA\HEA) of transition metals for the electrochemical reduction of CO2.
The MEA\HEA are multi principal element alloys (MPEAs) consisting of more than three elements with almost equal alloying proportions, forming solid solutions without intermetallic phases. In such a crystal structure, the individual elements are well mixed, and each atom has different nearest neighbours. In catalysis, especially in selectivity, it is precisely this atomic chaos that matters. Due to the large number of possible combinations of elements, these materials offer excellent conditions to tune their functional properties for specific applications.
Especially, catalyst systems in which Cu is combined with another metallic component show a significant increase in catalytic efficiency compared to monometallic systems. Since the catalytic activity, selectivity, and stability of electrocatalysts strongly depend on the size and surface, systematic studies on the influence of the organic stabilizers on heterogeneous catalysis are also of interest.
The focus of this project is to design Cu-based MEA\HEA electrocatalysts on the atomic level. For this purpose, base alloys will be prepared, processed into high-purity nanoparticles by pulsed laser ablation, and tested as electrocatalysts.
T2 - Tag der Chemie 2023
CY - Berlin, Germany
DA - 05.07.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Electrocatalysis
PY - 2023
AN - OPUS4-59403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - MAPz@BAM Material Acceleration Plattform Zentrum @ BAM
N2 - Die Material Acceleration Platform der BAM (MAPz@BAM) bündelt unsere Automatisierungs-Expertise auf dem Gebiet der Materialwissenschaft und -prüfung. Wir entwickeln modulare Experimentmodule, automatische Prüf- und Auswerteverfahren und setzen künstliche Intelligenz für eine effiziente und autonome Versuchsplanung, - vorhersage und Datenanalyse ein.
T2 - Kick off Meeting / EnerMAC ZIM Network
CY - Berlin, Germany
DA - 07.12.2023
KW - Material Acceleration Platforms (MAPs)
KW - Self-driving-labs (SDLs)
KW - MAPz@BAM
PY - 2023
AN - OPUS4-59411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - Additive manufacturing of ceramics from water-based feedstocks with low binder content
N2 - A major challenge in the current ceramic additive manufacturing is the debinding of the printed parts, which is often associated with long process times and limitations in size and wall thickness.
Binder jetting, a powder-based AM technology, can in principle generate thick-walled parts with a low amount of organics and with high productivity. However, this technology is often not capable of handling the fine powders required as raw materials for most technical ceramics. In this context, the "layerwise slurry deposition" (LSD-print) has been developed as a layer deposition method using water-based ceramic slurry feedstocks, enabling binder jetting also for advanced ceramic materials. LSD-print thus combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality technical ceramics.
Perspectives and limitations of the LSD-print will be presented, with focus on achieving short debinding cycles and high productivity.
T2 - MS&T
CY - Pittsburgh, PA, USA
DA - 06.10.2024
KW - Additive Manufacturing
KW - Ceramic
KW - Binder
KW - Slurry
KW - Water-based
PY - 2024
AN - OPUS4-61882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - The potential of Material Acceleration Platforms (MAPs) for creating resilient and sustainable technology value chains
N2 - Material Acceleration Platforms (MAPs) represent a transformative approach to the development of resilient and sustainable technology value chains. These platforms can identify candidate chemistries and structures via simulations, and database searches and leverage machine learning-based rapid screening to accelerate the discovery and deployment of novel materials, thereby addressing critical challenges in modern technology sectors.
Incorporating high-fidelity advanced characterization in the early phases of material development is crucial for early de-risking. Advanced characterization techniques, such as X-ray diffraction, advanced electrochemical and spectroscopic techniques provide comprehensive insights into the structural, chemical, and physical properties of materials. Long-term testing further contributes to the de-risking process by evaluating the durability and stability of materials under various environmental and operational conditions. Early identification of potential degradation mechanisms enables the refinement of material compositions and processing methods, ultimately leading to the development of more resilient materials.
Early upscaling attempts are integral to assessing the feasibility of material leads generated through machine learning-based rapid screening to evaluate the scalability of synthesis and processing techniques. This step is critical for identifying potential challenges in manufacturing, such as issues related to reproducibility, yield, and cost-effectiveness. Process design has to be a major part of the MAP-based material design to cope with the increasing share of secondary raw materials in supply chains.
This presentation will briefly summarize possible strategies to address these issues and provide deep-dives on best practices. As the demand for advanced materials continues to grow, MAPs will play an increasingly vital role in driving technological advancements and addressing global challenges.
T2 - Materials Week Cyprus 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - MAPs
KW - SDLs
KW - Sustainability
PY - 2024
AN - OPUS4-60379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Saber, Yassin
T1 - Fully automated and decentralized fused filament fabrication of ceramics for remote applications
N2 - Manufacturing of ceramic components in remote (i.e., geographically isolated) settings poses significant challenges where access to conventional manufacturing facilities is limited or non-existent. Fused Filament Fabrication (FFF) enables the rapid manufacturing of ceramic components with complex geometries. Parts formed by FFF require subsequent debinding and sintering to reach full density. Debinding and sintering are typically executed in separate steps with different equipment, necessitating extensive human handling which hinders process automation and may be challenging for the operator in isolated environments. This poster presents an innovative approach: the integration of all process steps into a single, fully automated system, streamlining the process and minimizing human involvement. Our system combines a dual extrusion filament printer with a porous and heat-resistant ceramic print bed. The porous print bed enables mechanical interlocking of the first printed layers, ensuring adhesion and structural integrity during FFF. Ceramic parts are printed onto thin sacrificial rafts, which are built using an interface material with the same binder as the ceramic filament. After the print is completed, the heat-resistant print bed with all parts is transferred seamlessly with a carrier system into a high-temperature furnace for debinding and sintering. During sintering the sacrificial raft is disintegrated, allowing for unconstrained sintering of the ceramic parts and easy removal of the finished parts. In conclusion, our integrated approach enables significant advancements in the fabrication of complex ceramic components in remote environments with increased efficiency and minimal human handling.
T2 - yCAM 2024
CY - Tampere, Finnland
DA - 06.05.2024
KW - Fused Filament Fabrication
PY - 2024
AN - OPUS4-60057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madbouly, Loay Akmal
T1 - Chemical analysis of commercial functionalized graphene along the production process
N2 - Graphene has been commercialized for over a decade. For many applications like flexible electronics, coating of different materials like paper or for textiles, it used in the form of suspensions or inks. Functionalization enables tailoring the properties of graphene, such as the sheet resistance. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy are used to characterize the chemical composition of graphene flakes, functionalized and otherwise. In this study, we investigate the following set of commercial materials: fluorine-functionalized graphene (F-graphene) and nitrogen-functionalized graphene (N-graphene) as well as unfunctionalized graphene (G-graphene, as the starting material) in the forms of powders, suspensions, and inks, the latter as the final commercial product. Raman spectroscopy and XPS are complementary techniques. Our results obtained from Raman spectroscopy confirmed the existence of graphene structures in all samples investigated and provided a comparative insight on the structural defects between samples. XPS was used to investigate the chemical states of elements in graphene, such as sp2 and sp3 hybridization states of carbon, as well as the chemical effect of functionalization on graphene. High resolution XPS analysis was performed for C 1s, F 1s and N 1s core-levels for all the graphene samples. The XPS results showed the elemental composition and the impurities of each sample. All powders showed less presence of carboxyl groups, compared to their respective suspensions and inks. F-functionalized suspension and inks showed a significant decrease in the at-% of fluorine relative to the powder. These valuable insights, particularly when correlated, allowed the tracking of the structural and chemical changes of graphene along its production process.
T2 - 3rd FUB Nano Colloquium
CY - Berlin, Germany
DA - 15.07.2025
KW - Functionalized graphene
KW - Graphene-related 2D materials (GR2M)
KW - Raman Spectroscopy
KW - XPS
KW - Inks
PY - 2025
AN - OPUS4-64116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madbouly, Loay Akmal
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Raman Spectroscopy and X-ray Photoelectron Spectroscopy of Commercial Functionalized Graphene
N2 - Graphene has found widespread commercial use, particularly in flexible electronics and coatings for substrates such as paper and textiles, in the form of suspensions and inks (Zhang et al., 2017). Functionalization of graphene allows fine-tuning of properties like electrical conductivity. Structural and chemical features of graphene materials are typically analyzed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). While Raman spectroscopy plays a critical role in identifying the presence of graphene and characterizing its structural defects (Pollard et al., 2017), XPS examines the chemistry of graphene. This study investigates three types of graphene materials — graphene (unfunctionalized, G-graphene), fluorine-functionalized graphene (F-graphene), and nitrogen-functionalized graphene (N-graphene) — across three physical forms: powders, suspensions, and embedded in inks. Functionalization was performed via plasma treatment of G-graphene with fluorine or ammonia gases. Suspensions were obtained by dispersing powders in distilled water, while inks were formulated using diacetone alcohol, carbon black, and graphene. Raman spectroscopy analysis confirmed the graphitic nature of all materials and revealed differences in defect density across different forms. The characteristic D, G, and D’ bands varied in relative intensity, offering insight into structural integrity and functionalization effects. XPS measurements examined core-level spectra (C 1s, F 1s, N 1s), revealing chemical bonding environments and hybridization states, including the sp² and sp³ states. A notable decline in fluorine content in F-graphene suspensions and inks, relative to powders, was observed. Existence of organic fluorine and total absence of metallic fluorine were observed. Raman spectroscopy and XPS data provided a correlated view of structural and chemical evolution through the graphene production chain.
T2 - Joint Regulatory Risk Assessors Summit – Advancing Safety & Sustainability Assessments of Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - Graphene-related 2D materials (GR2M)
KW - Inks
KW - Raman Spectroscopy
KW - XPS
KW - Functionalized graphene
PY - 2025
UR - https://macrame-project.eu/macrame-meetings-workshops/jointrras/#Agenda
AN - OPUS4-63661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodriguez, Santiago
A1 - Kumanski, Sylvain
A1 - Ayed, Zeineb
A1 - Fournet, Aurélie
A1 - Bouanchaud, Charlène
A1 - Sagar, Amin
A1 - Allemand, Frédéric
A1 - Baulin, Vladimir A.
A1 - Resch‐Genger, Ute
A1 - Cortés, Juan
A1 - Sibille, Nathalie
A1 - Chirot, Fabien
A1 - Wegner, Karl David
A1 - Antoine, Rodolphe
A1 - Le Guével, Xavier
A1 - Bernadó, Pau
T1 - Programming the Optoelectronic Properties of Atomically Precise Gold Nanoclusters Using the Conformational Landscape of Intrinsically Disordered Proteins
N2 - The rational design of hybrid nanomaterials with precisely controlled properties remains a central challenge in materials science. While atomically precise gold nanoclusters (Au‐NCs) offer molecule‐like control over a metallic core, tuning their optoelectronic behavior via surface engineering is often empirically driven. Here, we establish a design principle by demonstrating that the conformational landscape of intrinsically disordered proteins (IDP) can be used as a programmable scaffold to rationally modulate the photophysical properties of a covalently bound Au‐NC. We synthesized a series of bioconjugates between Au 25 nanoclusters and bioengineered IDPs containing a variable number of cysteine anchoring points. A combination of mass spectrometry, small‐angle X‐ray scattering, and modeling on the conjugates indicates that increasing the number of covalent anchors systematically restricts the conformational ensemble, inducing a progressively more compact protein shell around nanoclusters. This structural rigidification at the interface directly translates into a 15‐fold enhancement of the Au‐NC near‐infrared photoluminescence and a six‐fold increase in its average lifetime. Our findings demonstrate that the conformational plasticity of IDPs and the capacity to engineer them can be harnessed as a molecular tuning knob, moving to a new regime of programmable soft‐matter control over the properties of quantum‐confined nanomaterials for tailored biotechnological applications.
KW - Fluorescence
KW - Custer
KW - Nano
KW - Advanced material
KW - Characterization
KW - Fluorescence quantum yield
KW - Integrating sphere spectroscopy
KW - Thiol ligands
KW - Gold
KW - Surface chemistry
KW - SWIR
KW - Mass spectrometry
KW - Protein
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655086
DO - https://doi.org/10.1002/chem.202502991
SN - 0947-6539
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-65508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Tamang, S.
A1 - Wegner, Karl David
A1 - Reiss, P.
ED - Alivisatos, P.
ED - Jang, E.
ED - Ma, R.
T1 - Quantum Dot Material Systems, Compositional Families
N2 - Following the discovery of the quantum confinement effect in the early 1980s, it took more than 10 years to be able to synthesize monodisperse colloidal quantum dots (QDs) using organometallic chemistry approaches. The researchers behind these pioneering works, Alexey Ekimov, Louis Brus, and Moungi Bawendi, were awarded the Nobel Prize in Chemistry in 2023, exactly 30 years after the seminal report on the preparation of cadmium chalcogenide QDs. From the synthetic point of view, this approach, relying on the fast injection of a chalcogenide precursor dissolved in a tertiary phosphine into a hot solution of the cadmium precursor in a coordinating solvent (trioctylphosphine oxide, TOPO) acting at the same time as surface ligand, was revolutionary. It enabled the fast synthesis of wellcrystallized CdS, CdSe, and CdTe QDs of low size dispersion and high colloidal stability, whose size and hence optical and electronic properties could be conveniently tuned with the reaction time. Due to the comparable ease of this method and the later developed shelling procedures with ZnS, ZnSe, CdS, and mixtures or alloys of these materials, CdSe has become the workhorse for the entire QD field, covering the whole visible range of absorption and emission.
Meanwhile, several breakthroughs have been achieved, which enabled us to bring QDs to their maturity of today and integrate them in several applications, in particular those relying on their exceptional luminescence properties, such as biological imaging as well as displays and screens. For such real-life applications, the quest for less toxic, safer-to-use, and environmentally friendly materials is of utmost importanceand a highly active research field. The use of cadmium- and lead-based materials is severely restricted by regulations such as the RoHS directive of the European Union: the maximum concentrations of lead and cadmium are 0.1 and 0.01% by weight, respectively, in all homogeneous materials in electrical and electronicequipment. Several families of alternative materials have been explored, with the most important ones for display technologies being indium phosphide (InP)- and ternary chalcopyrite-type QDs.
KW - Quantum dots
KW - Photoluminescence
KW - LED
KW - Display technology
PY - 2025
SN - 978-1-394-18187-2
SP - 23
EP - 62
PB - John Wiley & Sons Ltd.
AN - OPUS4-64675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rastgou, Masoud
A1 - Hülagü, Deniz
A1 - Danilenko, Aleksandr
A1 - Manoocheri, Farshid
A1 - Hertwig, Andreas
A1 - Ikonen, Erkki
T1 - Comparison of thin-film thickness measurements using ellipsometry and reflectometry with uniform samples
N2 - This study evaluates spectroscopic ellipsometry and reflectometry using high-quality SiO2 and Al2O3 thin-films on Si substrates, thereby facilitating a detailed assessment of consistency of measurement results and uncertainty analyses. The results with detailed uncertainty budgets indicate good agreement between the two methods across a broad layer thickness range from 10 nm to 2000 nm, with deviations remaining well within the measurement uncertainties. Ellipsometry results have lower uncertainty than reflectometry results especially with the thinner layers, whereas reflectometry uncertainties are lower with the thickest layers studied. This work underscores the importance of rigorous thickness characterization and reliable uncertainty evaluation as critical factors in advancing both modeling and measurement practices in thin-film metrology.
KW - Ellipsometry
KW - Reflectometry
KW - Thin Film Metrology
KW - Measurement Accuracy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655209
DO - https://doi.org/10.1088/1681-7575/ae3964
SN - 0026-1394
VL - 63
IS - 1
SP - 1
EP - 14
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-65520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Fritzsche, Sven
A1 - Weimann, Christiane
A1 - Pauw, Brian Richard
A1 - Sturm, Heinz
T1 - 2PP-TestArtifact
N2 - This repository contains a test artifact (TA), also called test structure, designed for two-photon polymerization (also known as Direct Laser Writing (DLW) or Two/Multi-photon lithography (2PA/MPA)). Test artifacts can be used to compare structures, to check options used by the slicer, check the state of the 2PP machine itself or to get a construction guidelines for a certain combination of power, velocity and settings.
The associated paper can be found here: https://dx.doi.org/10.1088/1361-6501/acc47a
General ideas behind the test artifact:
1. optimized for 2PP-DLW
2. should be fast and easy to analyse with optical microscopy or 3. scanning electron microscopy without tilt.
3. short time to fabricate
4. include a reasonable amount of different features
5. bulk and small structures on the substrate
KW - Reference structure
KW - Calibration structure
KW - Test structure
KW - Laser writing
KW - Two-photon polymerization
KW - 3D printing
KW - Additive manufacturing
KW - Microprinting
KW - Multi-photon light structuring
PY - 2023
DO - https://doi.org/10.6084/m9.figshare.22285204.v2
PB - Digital Science
CY - Cambridge, MA, USA
AN - OPUS4-57165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weltschev, Margit
T1 - Bewertung der Beständigkeit von metallenen und polymeren Werkstoffen in Mitteldestillatanwendungen mit Zusatz von Biodiesel
N2 - Für Bauteile (Komponenten) von Versorgungsanlagen für flüssige Brenn- und Kraftstoffe muss die Beständigkeit der metallenen Werkstoffe und Polymere nachgewiesen werden. Im Anwendungsfall von Heizöl mit 20 % biogenen Anteilen in Form von Rapsölfettsäuremethylester (FAME, Biodiesel) ist es für eine konservative Beurteilung des Korrosionssystems Werkstoff/Medium/Umgebung wichtig, die Alterungseffekte des Mediums einzubeziehen.
Entwicklung eines Prüfverfahrens für die Untersuchung der Beständigkeit von metallenen Werkstoffen und Polymeren in Heizöl und Heizöl-Biodiesel-Blends, das für eine Vorauswahl der Werkstoffe und zum Nachweis der Beständigkeit im Hinblick auf die bauaufsichtlichen Zulassungsverfahren geeignet ist. Ein Schwerpunkt wird bei den metallenen Werkstoffen auf der Erprobung von Messmethoden liegen, mit denen sich in kurzer Versuchszeit ein Korrosionsangriff detektieren lässt.
T2 - Seminar: Ausgewählte Kapitel der Werkstofftechnik an der Bergischen Universität Wuppertal
CY - Wuppertal, Germany
DA - 24.01.2020
KW - Heizöl-20% Biodiesel-Blend
KW - Beständigkeitsuntersuchungen
KW - Metallene Werkstoffe
KW - Polymerwerkstoffe
PY - 2020
AN - OPUS4-50298
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Materials interactions in geothermal plants – not just an aspect of durability
N2 - High alloyed corrosion resistant alloys are suitable for high saline geothermal fluids and do not cause copper or lead deposition. They shall be chosen for future design of the piping system, either in massive or in cladded form, if crevices formation with non-metallic materials can be prevented! Otherwise Ni-based alloys or Ti shall be selected.
T2 - IFPEN Webinar "Corrosion in geothermal energy production"
CY - Online meeting
DA - 26.06.2025
KW - Corrosion
KW - Geothermal
KW - Electrochemistry
PY - 2025
AN - OPUS4-63528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
A1 - Sänger, Johanna
A1 - Zocca, Andrea
T1 - Continuous layer deposition for the Additive Manufacturing of ceramics by Layerwise Slurry Deposition
N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders.
In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method enabling the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder. Not only very fine, submicron powders can be processed with low organics, but also the dense powder bed provides excellent support to the parts built.
The latest development of this technology shows that it is possible to print ceramic parts in a continuous process by depositing a layer onto a rotating platform, growing a powder bed following a spiral motion. The unique mechanical stability of the layers in LSD-print allows to grow a powder bed several centimeters thick without any lateral support. The continuous layer deposition allows to achieve a productivity more than 10X higher compared to the linear deposition, approaching a build volume of 1 liter/hour.
T2 - DKG Jahrestagung 2024
CY - Höhr-Grenzhausen, Germany
DA - 09.09.2024
KW - Ceramic
KW - Additive manufacturing
PY - 2024
AN - OPUS4-61051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Metallene Werkstoffe in Geothermieanlagen - nicht nur aus Sicht der Korrosion
N2 - Um Konstrukteuren und Nutzern geothermischer Anlagen grundlegende Informationen über die Korrosionsbeständigkeit zur Verfügung zu stellen, wurden verschiedene metallene Werkstoffe, darunter nichtrostende Duplex- und austenitische Stähle sowie eine Nickellegierung, in künstlichen Geothermalwässern, die die Bedingungen an verschiedenen Standorten mit geothermischem Potenzial simulieren, mit Hilfe von elektrochemischen und Langzeittests hinsichtlich ihrer Eignung bewertet.
In hochsalinaren Umgebungen erwies sich Spaltkorrosion als der entscheidende Mechanismus. Die Nickellegierung zeigt eine ausgezeichnete Beständigkeit gegenüber Lochkorrosion. Abgesehen von ihren hohen Kosten eignet sie sich sehr gut für den Bau von Geothermieanlagen mit stark salzhaltigen Fluiden. Rostfreie Stähle und Duplexstähle weisen eine begrenzte Korrosionsbeständigkeit gegen Loch- und Spaltkorrosion auf. Daher sind sie für stark salzhaltige Fluide nicht geeignet. Der Superaustenit zeigt ein temperaturabhängiges Verhalten. In nichtsalinaren Umgebungen könnten niedriglegierte Stähle (neben den höherlegierten Werkstoffen) als Konstruktionsmaterial für Geothermieanlagen eingesetzt werden, sofern eine ausreichende Wandstärke des Materials berücksichtigt wird.
Neben Korrosionsaspekten erwies sich auch die Ausfällung von Fluidbestandteilen als interessantes Thema. Beim Betrieb der Forschungsanlage in Groß Schönebeck wurden Kupfer- und Bleieffekte im Bohrloch festgestellt. Die auftretenden Mechanismen und Maßnahmen zur Verhinderung von Ausfällungen und Abscheidungen wurden ebenso untersucht, wie deren mögliche Einflüsse auf die Korrosionsbeständigkeit metallener Werkstoffe für Anlagenkomponenten.
Der Beitrag beschreibt die Wechselwirkungen zwischen Geothermalwässern und Ausrüstungskomponenten.
T2 - 57. Kraftwerktechnisches Kolloquium
CY - Dresden, Germany
DA - 07.10.2025
KW - Örtliche Korrosion
KW - Edelstahl
KW - Ni-Legierungen
KW - Geothermie
KW - Abscheidung
PY - 2025
AN - OPUS4-64323
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - MAPz@BAM Material Acceleration Plattform Zentrum @ BAM
N2 - Die Material Acceleration Platform der BAM (MAPz@BAM) bündelt unsere Automatisierungs-Expertise auf dem Gebiet der Materialwissenschaft und -prüfung. Wir entwickeln modulare Experimentmodule, automatische Prüf- und Auswerteverfahren und setzen künstliche Intelligenz für eine effiziente und autonome Versuchsplanung, - vorhersage und Datenanalyse ein.
T2 - TechConnect Adlershof: Grand Solutions
CY - Berlin, Germany
DA - 06.11.2023
KW - Material Acceleration Platforms (MAPs)
KW - Self-driving-labs (SDLs)
KW - MAPz@BAM
PY - 2023
AN - OPUS4-59412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meyer, Lena
T1 - How will we explore, work, and live on the moon?
N2 - 3D-printed landing pads on the moon: Paving the road for large area sintering of lunar regolith.
A prerequisite for lunar exploration and beyond is the manufacturing of objects directly on the moon, given the extreme costs involved in the shipping of material from Earth. Looking at processes, raw materials, and energy sources, equipment will certainly have to be brought from Earth at the beginning. Available on the moon are lunar regolith as raw material and the sun as an energy source. One of the first steps towards the establishment of a lunar base is the creation of infrastructure elements, such as roads and landing pads.
We’ll introduce you to the ESA-project PAVER that demonstrates the sintering and melting of lunar regolith simulant material to produce large scale 3D printed elements that could be used during human and robotic lunar explorations.
T2 - Berlin Science Week
CY - Online meeting
DA - 09.11.2022
KW - Additive manufacturing
KW - Lunar regolith simulant
KW - EAC-1A
KW - Space exploration
PY - 2022
UR - https://www.youtube.com/watch?v=StfLuVhKkUE
AN - OPUS4-56377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wetzel, Annica
T1 - The Interplay of Anodic Passivation and Oxygen Evolution of Medium Entropy Alloys in Aqueous NaCl Electrolytes at Different pH
N2 - Due to their favorable mechanical and anti-corrosion properties, medium entropy alloys (MEA) are of high academic and industrial interest as novel materials for engineering and catalytic applications. Previous studies on general corrosion behavior indicate high current densities at high anodic potentials for MEAs. Further investigations of the underlying transpassive dissolution and local corrosion behavior remain scarce.
To understand the passivation behavior of MEAs CrCoNi and FeCrNi at high anodic potentials, the mechanisms of transpassive dissolution and the oxygen evolution reaction were investigated in this project. Scanning electrochemical microscopy (SECM) was applied in the interrogative mode for the detection of evolving metal species and oxygen. By means of ICP-MS analysis, dissolved metal species were quantified to provide a fundamental understanding on the transpassive dissolution. As the oxygen evolution reaction (OER) may contribute a large percentile to the observed current at high anodic potentials, SECM measurements were employed to analyze the onset of the OER. Potentiodynamic, potentiostatic and chronoamperometric techniques as well as different electrolytes were used to induce precisely controlled corrosion loads during the SECM experiments and for the ICP-MS analysis. Macroscopic corrosion properties of the alloys, electrical and chemical properties of the passive films were studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and X-Ray Photoelectron Spectroscopy (XPS), respectively.
Finally, the analysis of the corrosion morphology and the potential of the surface before, during and after passivity breakdown was carried out by means of in-situ atomic force microscopy (AFM) and scanning Kelvin probe force microscopy (SKPFM). The presentation will summarize our results on the interplay of anodic passivation and oxygen evolution of MEAs in aqueous NaCl electrolytes.
T2 - MRS Spring 2023
CY - San Francisco, California, USA
DA - 10.04.2023
KW - Chemically Complex Materials
KW - CCMat
KW - Corrosion
PY - 2023
AN - OPUS4-59405
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wetzel, Annica
T1 - Local corrosion properties of high/medium entropy alloys in aqueous environments
N2 - High and medium entropy alloys gained increasing academic and industrial interest as novel materials for engineering applications. This project is aiming to clarify and compare the general and local corrosion properties of high entropy alloy CrMnFeCoNi and medium entropy alloy CrCoNi in different aqueous environments. The focus lies on the local corrosion processes that result either from microstructural imperfections (inclusions, defects at grain boundaries etc.) in the base material or processing related changes in the microstructure and/or local composition.
The corrosion behavior of the alloys was monitored via potentiodynamic polarization experiments and the local corrosion characteristics were further investigated by means of scanning electrochemical microscopy (SECM). Their passivation behavior was analyzed in three different electrolyte systems (NaCl, H2SO4 and NaClO4; c = 0.1M). The characterization of the surface morphology and composition of the passive film was performed by means of atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-Ray spectroscopy (SEM/EDX) and X-Ray photoelectron spectroscopy (XPS), respectively.
Considering long term corrosion effects, electrochemical work was supported with immersion tests and the analysis of corrosion products by SEM/EDX and XPS depth-profiling. Our results indicate that the medium entropy alloy CrCoNi has a significantly higher corrosion resistance in comparison to the high entropy alloy CrMnFeCoNi. The presentation will summarize some of our results on the mechanistical aspects of the observed high corrosion resistance.
T2 - EUROCORR 2020
CY - Online meeting
DA - 07.09.2020
KW - High Entropy Alloys
KW - Corrosion
KW - Medium Entropy Alloys
KW - Atomic Forc Microscopy
KW - Scanning Kelvin Probe Force Microscopy
KW - Potentiodynamic Polarization
PY - 2020
AN - OPUS4-53787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wetzel, Annica
T1 - Corrosion Properties and Protective Oxide Film Characteristics of CrMnFeCoNi High Entropy Alloy and CrCoNi Medium Entropy Alloy
N2 - High and medium entropy alloys gained increasing academic and industrial interest as novel materials for engineering applications. This project is aiming to clarify and compare the general and local corrosion properties of high entropy alloy CrMnFeCoNi and medium entropy alloy CrCoNi in different aqueous environments. The focus lies on the local corrosion processes that result either from microstructural imperfections (inclusions, defects at grain boundaries etc.) in the base material or processing related changes in the microstructure and/or local composition.
The corrosion behavior of the alloys was monitored via potentiodynamic polarization experiments and the local corrosion characteristics were further investigated by means of scanning electrochemical microscopy (SECM). Their passivation behavior was analyzed in three different electrolyte systems (NaCl, H2SO4 and NaClO4; c = 0.1M). The characterization of the surface morphology and composition of the passive film was performed by means of atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-Ray spectroscopy (SEM/EDX) and X-Ray photoelectron spectroscopy (XPS), respectively.
Considering long term corrosion effects, electrochemical work was supported with immersion tests and the analysis of corrosion products by SEM/EDX and XPS depth-profiling. Our results indicate that the medium entropy alloy CrCoNi has a significantly higher corrosion resistance due to the higher concentration of Chromium in comparison to the high entropy alloy CrMnFeCoNi. The presentation will summarize our results on the mechanistical aspects of the observed high corrosion resistance.
T2 - EUROCORR 2021
CY - Online meeting
DA - 20.09.2021
KW - High Entropy Alloys
KW - Aqueous Corrosion
KW - Medium Entropy Alloys
KW - Atomic Forc Microscopy
KW - Scanning Kelvin Probe Force Microscopy
KW - Potentiodynamic Polarization
KW - Electrochemical Impedance Spectroscopy
KW - ICP-MS
PY - 2021
AN - OPUS4-53791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quosdorf, Heike
T1 - Digital object identifier for additively manufactured parts based on 3D microstructural information
N2 - Additive manufacturing (AM) is rapidly emerging from prototyping to industrial production [1]. Thus, providing AM parts with a tagging feature that allows unambiguous identification, can be crucial for logistics, certification, and anti-counterfeiting purposes. The digital object identifier (DOI) acts like a fingerprint for the product throughout its entire lifecycle. Several methods are already available, which range from encasing a detector [2] to leveraging the stochastic defects of AM parts [3], printing a quick response (QR) code or a set of voids partially filled with loose powder within the part [3]. A new method is using microstructural features of the AM part without altering their properties. This technology transfer project aims to implement this authentication methode as software solution to act as certificate in the Digital Product Passport (DPP) [5].
T2 - MaterialDigital General Assembly 2025
CY - Berlin, Germany
DA - 26.11.2025
KW - Authentication
KW - Unique identification
KW - Open Science
KW - Digital fingerprint
KW - Material Digital
KW - X-ray Computed Tomography
KW - Additive manufacturing
PY - 2025
AN - OPUS4-65208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - A Coating System for Corrosion Protection of Carbon Steel as an Alternative for High Alloyed Materials
N2 - The screening of coatings shows that the modification by adding individual pigment was not sufficient to protect carbon steel even during a short-term exposure, indicated by the discoloration after only seven days of exposure.
Electrochemical tests indicated that the coating cathodically protects carbon steel or slows down the corrosion reaction.
A long-term exposure test confirmed that the PANI/SiO2 modified coating successfully protects the carbon steel in the Sibayak artificial geothermal water at 150 °C for 6 months.
T2 - European Geothermal Congress
CY - Berlin, Germany
DA - 17.10.22
KW - Corrosion
KW - Geothermal
KW - Coatings
KW - Polyaniniline
KW - Silicate
PY - 2022
AN - OPUS4-56084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bäßler, Ralph
T1 - Review: Science, Technology and Applications of Metals in Additive Manufacturing
N2 - Often 3D‐printing and additive manufacturing are mentioned as the 3rd industrial revolution. In this conjunction this book provides a brief overview on additively manufactured metal pieces.
This book fulfills its intension to serve as an educational guide, providing a holistic picture encompassing science, technology and applications for the real‐life use of Metal Additive Manufacturing.
KW - Additive manufacturing
KW - Corrosion
KW - Material properties
PY - 2020
DO - https://doi.org/10.1002/maco.202070114
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 11
SP - 1929
EP - 1930
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weltschev, Margit
T1 - Compatibility of polymers with aged heating oil containing 10 % and 20 % biodiesel under static conditions
N2 - Biodiesel is viewed as a major source of energy. In areas such as the European Un-ion, where 80 % of the oil-based fuel is imported, there is also the desire to reduce dependence on external oil supplies.
Materials compatibility is a major concern whenever the fuel composition is changed. The question arises of whether polymeric materials are resistant to heating oil with 20 % biodiesel (B20) in comparison to pure heating oil.
The polarity of biodiesel increases its solvency and facilitates permeation and extrac-tion. Solvation, swelling and/or extraction lead to changes in the physical properties. Extraction alters the fuel chemistry. These chemical changes could also accelerate the degradation (hydrolysis and oxidation) of the polymeric material with the loss of additives and stabilizers.
Exposure tests to determine the resistance of polymers frequently used for compo-nents in middle distillate facilities, such as ACM, FKM, HNBR, PA, PE, POM, PUR and PVC in heating oil and a blend of heating oil and 20 % biodiesel (B20) were al-ready performed.
The objective of this research was to determine the resistance of these polymers in 8-year aged heating oil blend B10 and 1-year aged blend B20 at 40 °C.
Mass, tensile strength, breaking elongation and Shore hardness A (D) of the test specimens were determined before and after exposure for 84 (42) days in the test fuels under static conditions.
There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was deter-mined for the evaluation of the compatibility.
A significant reduction in Shore hardness was determined after exposure of ACM and PUR test specimens in 1-year aged B20.
The tensile strength of PUR test specimens in 1-year aged B20 was reduced by more than 50 %, and the breaking elongation by more than 30 %.
A decrease in breaking elongation was measured for POM test specimens after ex-posure to 1-year aged B20 by 25 % (limited resistance).
8-year aged B10 had a stronger effect than 1-year aged B20 on the polymers. ACM test specimens were softened by B10 resulting in a drop of Shore hardness by over 20 %. B10 reduced tensile strength and breaking elongation of PUR test specimens by over 50 %. In contrast, the breaking elongation of POM was increased by over 270 %.
It can be concluded that the polymers HNBR, FKM, PA6, PE and PVC are resistant in 1-year aged B20 whereas ACM and POM are limited resistant. PUR is not re-sistant.
HNBR, FKM, PA6, PE and PVC are resistant in 8-year aged B10, whereas PUR and POM are not resistant, and ACM just limited resistant.
T2 - EUROCORR 2020
CY - Online meeting
DA - 07.09.2020
KW - Aged heating oil with 10% and 20% biodiesel
KW - Resistance of polymers
KW - Tensile properties
KW - Shore hardness
PY - 2020
AN - OPUS4-51240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wetzel, Annica
T1 - Corrosion Properties and Protective Oxide Film Characteristics of CrMnFeCoNi High Entropy Alloy and CrCoNi Medium Entropy Alloy
N2 - High and medium entropy alloys gained increasing academic and industrial interest as novel materials for engineering applications. This project is aiming to clarify and compare the general and local corrosion properties of high entropy alloy CrMnFeCoNi and medium entropy alloy CrCoNi in different aqueous environments. The focus lies on the local corrosion processes that result either from microstructural imperfections (inclusions, defects at grain boundaries etc.) in the base material or processing related changes in the microstructure and/or local composition.
The corrosion behavior of the alloys was monitored via potentiodynamic polarization experiments and the local corrosion characteristics were further investigated by means of scanning electrochemical microscopy (SECM). Their passivation behavior was analyzed in three different electrolyte systems (NaCl, H2SO4 and NaClO4; c = 0.1M). The characterization of the surface morphology and composition of the passive film was performed by means of atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-Ray spectroscopy (SEM/EDX) and X-Ray photoelectron spectroscopy (XPS), respectively.
Considering long term corrosion effects, electrochemical work was supported with immersion tests and the analysis of corrosion products by SEM/EDX and XPS depth-profiling. Our results indicate that the medium entropy alloy CrCoNi has a significantly higher corrosion resistance due to the higher concentration of Chromium in comparison to the high entropy alloy CrMnFeCoNi. The presentation will summarize our results on the mechanistical aspects of the observed high corrosion resistance.
T2 - EuroMat 2021
CY - Online meeting
DA - 12.09.21
KW - High Entropy Alloys
KW - Aqueous Corrosion
KW - Medium Entropy Alloys
KW - Atomic Forc Microscopy
KW - Scanning Kelvin Probe Force Microscopy
KW - Potentiodynamic Polarization
KW - Electrochemical Impedance Spectroscopy
KW - ICP-MS
PY - 2021
AN - OPUS4-53790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Evaluation of Corrosion Resistance of Metallic Materials in Geothermal Applications
N2 - Evaluation of corrosion resistance of metallic materials is essential to assure safe and reliable operation of geothermal sites. One need to be aware that corrosion is not a material's but a system property, determined by medium, material and construction aspects. Various corrosion types have to be evaluated. Conditions in laboratory shall reflect on-site reality. Depending on brine composition and temperature suitability of metallic materials can be ranked. Most important outcome of the research is that highly saline geothermal brines require high alloyed materials, for safe long-term operation.
T2 - Geothermal Essentials - Moving Geothermal Forward in Canada: Scaling and Corrosion (Surface Facilities)
CY - Online Webinar
DA - 16.03.2022
KW - Corrosion
KW - Geothermal
KW - Steel
PY - 2022
AN - OPUS4-54482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Rezension: Materialkunde der Nichteisenmetalle und ‐legierungen
N2 - Die Werkstoffklasse der Nichteisenmetalle gewinnt wegen ihrer unzähligen Anwendungsmöglichkeiten nicht nur im Maschinen‐ und Anlagenbau eine immer größere technische und wirtschaftliche Bedeutung, sodass es unabdingbar ist, insbesondere Studierenden der Material‐ und Werkstoffwissenschaften und des Maschinenbaus, den aktuellen Wissensstand auf diesem Gebiet zu vermitteln. Mit dieser Neuerscheinung veröffentlicht der Wiley‐VCH‐Verlag ein solches Lehrbuch. Kompakt und übersichtlich machen die beiden Autoren den Leser in 10 Kapiteln auf verständliche Art mit dieser Thematik vertraut. Dabei kommt ihnen ihre durch langjährige Lehrtätigkeit erworbene didaktische Erfahrung sehr zugute.
Alles in allem bietet dieses Lehrbuch durch seinen von den Natur‐, über Material‐ zu Ingenieurwissenschaften weitgespannten Bogen einen interessanten und übersichtlichen Einstieg in die Welt der am häufigsten verwendeten Nichteisenmetalle, wobei es keinen Anspruch auf Vollständigkeit erhebt.
KW - Werkstoffprüfung
KW - Legierung
KW - Korrosion
PY - 2020
DO - https://doi.org/10.1002/maco.202070086
SN - 1521-4176
VL - 71
IS - 8
SP - 4
PB - Wiley‐VCH
CY - Weinheim
AN - OPUS4-51073
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Corrosion Effects on Materials Considered for CC(U)S Applications
N2 - Commercially available carbon steels are suitable for compression and pipelines as long as moisture content and impurities are limited. (water 50 to 100 ppmv, SO2 and NO2 ca. 100 ppmv) Corrosion rates increase with increasing water content. (0.2 – 20 mm/a) Condensation of acids and therefore droplet formation is always possible, even at low water contents. A low SO2 content within the CO2-stream might be more important than a low water content. Cr13-steels showed a general susceptibility to shallow pitting and pitting. So, they seem to be not suitable for CCUS applications. Low alloyed steels showed better corrosion behavior (predictable uniform corrosion). For direct contact with saline aquifer fluids only high alloyed steels shall be used.
T2 - EFC Webinar
CY - Online Meeting (Chongqing, China)
DA - 18.05.2022
KW - Corrosion
KW - CO2 quality
KW - CO2
KW - CCS
KW - CCU
KW - Pipeline
PY - 2022
AN - OPUS4-54854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - ISO 27913 - Example For Successful Standardization Activities In The Field Of CCUS
N2 - Since 2016 ISO Technical Committee (TC) 265 is working on standardization the whole CCS-process chain. Around 30 countries are working together to provide international guidelines. As ISO 27913 was the first standard finished within these activities it is already in the stage of first revision.
The objective of ISO 27913 is “to provide specific requirements and recommendations on certain aspects of safe and reliable design, construction and operation of pipelines intended for the large-scale transportation of CO2 that are not already covered in existing pipeline standards such as ISO 13623, ASME B31.8, EN 1594, AS 2885 or other standards. Existing pipeline standards cover many of the issues related to the design and construction of CO2 pipelines; however, there are some CO2 specific issues that are not adequately covered in these standards. The purpose of this document is to cover these issues consistently. Hence, this document is not a standalone standard, but is written to be a supplement to other existing pipeline standards for natural gas or liquids for both onshore and offshore pipelines.”
This contribution shall provide information on the content, the current stage of the revision process, encourage to contribute to this standard and make listeners aware to consider the influence of ISO standard on documents currently in draft.
T2 - AMPP's Annual Conference + Expo 2024
CY - New Orleans, LA, USA
DA - 02.03.2024
KW - Corrosion resistant materials
KW - Carbon dioxide
KW - Corrosion prevention
KW - Standardization
KW - CCUS
KW - CCS
KW - CCU
PY - 2024
AN - OPUS4-59736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Aristia, Gabriela
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
T1 - Integrated Coating System for Corrosion Protection of Carbon Steel in Artificial Geothermal Brine
N2 - Corrosive geothermal brines are a major challenge to geothermal power-plants. For cost reasons, plant designers prefer to use carbon and low alloyed steels, which are susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic and saline properties. To solve such problem, coatings or inhibitors would be a protective solution as an alternative to the use of high alloyed materials.
This study investigated a coating system consisting of polyaniline/silicon dioxide based on resources locally available in Indonesia. Protection against corrosion of carbon steel was shown by long-term (28 day) exposure and electrochemical tests of coated carbon steels, performed in an artificial acidic and saline geothermal brine, comparable to the conditions encountered at a site in Indonesia.
Therefore, an integrated coating system is proposed for corrosion protection, combining the electrochemical functionality of polyaniline and the physical advantages of silica.
T2 - AMPP International Corrosion Conference
CY - Online meeting
DA - 06.03.2022
KW - Geothermal
KW - Corrosion
KW - Coating
KW - Polyaniline
KW - Silicon dioxide
PY - 2022
SP - 1
EP - 11
CY - Houston TX (USA)
AN - OPUS4-54451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Deposition of Brine Components on Materials in Geothermal Conditions
T1 - ОСАЖДЕНИЕ КОМПОНЕНТОВ ГЕОТЕРМИЧЕСКИХ ВОД НА МАТЕРИАЛЫ В ГЕОТЕРМАЛЬНЫХ УСЛОВИЯХ
N2 - Since geothermal wells are a feasible energy source to replace fossil fuel supply, many technologies have been developed to take advantage of geothermal energy. Nevertheless, service conditions in geothermal facilities are in many cases extreme in terms of corrosion due to the chemical composition of hydrothermal fluids and temperatures. Therefore, materials selection based on preliminary material qualification is essential to guarantee a secure and reliable operation of the facilities. During operation of a geothermal research facility in Groß Schönebeck copper and lead effects have been found downhole. Occurring mechanisms and measures to prevent precipitation or scaling needed to be investigated as well as potential influences of such precipitates on corrosion resistance of metallic materials used for equipment.
This contribution deals with the evaluation of the corrosion behavior of carbon steel and corrosion resistant alloys in copper and/or lead containing artificial geothermal water, simulating the conditions in the Northern German Basin.
The behavior of these materials in an artificial geothermal water obtained by electrochemical measurements and exposure tests are presented. While carbon steel exhibits precipitation and deposition, higher alloyed material shows different response to such species and a higher resistance in saline geothermal water.
Basing on these results the suitability of the investigated corrosion resistant alloy is given for use in such conditions, whereas carbon steel creates difficulties due to its susceptibility to Cu- and Pb-precipitation.
N2 - Поскольку геотермальные скважины являются реальным источником энергии для замены поставок ископаемого топлива, было разработано множество технологий для использования преимуществ геотермальной энергии. Тем не менее, условия эксплуатации на геотермальных установках во многих случаях являются экстремальными с точки зрения коррозии из-за химического состава гидротермальных жидкостей и температур. Таким образом, выбор материалов на основе предварительной квалификации имеет важное значение для обеспечения безопасной и надежной работы геотермальных объектов. Во время работы исследовательской установки в Грос Шёнебек (Groß Schönebeck) в скважине было обнаружено воздействие меди и свинца. Необходимо изучить возникшие механизмы и меры для предотвращения депозиции или образования коррозии, а также потенциальное влияние таких осаждений на коррозионную стойкость металлов, используемых для оборудования. Этот доклад посвящен оценке коррозионного поведения углеродистой стали и коррозионно-стойких сплавов в геотермальной воде, содержащей медь и / или свинец, моделирующей условия в Северогерманском бассейне (North German basin). Представлено поведение этих металлических материалов в геотермальной воде, полученной путем электрохимических измерений и испытаний на воздействие. В то время как углеродистая сталь демонстрирует коррозию и отложения, высоколегированный материал демонстрирует более высокую стойкость в соленой геотермальной воде. На основании этих результатов пригодность исследуемого коррозионно-стойкого сплава дана для использования в данных условиях, тогда как углеродистая сталь создает трудности из-за ее восприимчивости к депозиции солей меди и свинца.
T2 - ХV International Conference Problems of Corrosion and Corrosion Protection of Materials “CORROSION-2020”
CY - Online meeting
DA - 15.10.2020
KW - Copper
KW - Lead
KW - Corrosion
KW - Steel
KW - Geothermal
PY - 2020
UR - http://www.ipm.lviv.ua/corrosion2020/
AN - OPUS4-51438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Influence of brine components on materials performance in geothermal applications
N2 - Significant Cu-deposition and ‑precipitation only occurred in combination with carbon steel. High-alloyed materials prevent the disturbing Cu-agglomeration. Pb-deposition and ‑precipitation only occurred in combination with carbon steel. No negative Pb-effect could be observed in combination with high-alloyed steels. High alloyed corrosion resistant alloys are suitable and shall be chosen for future design of the piping system, either in massive or in cladded form, if formation of crevices with non-metallic materials can be excluded!
T2 - EUROCORR 2022
CY - Berlin, Germany
DA - 28.08.2022
KW - Corrosion
KW - Geothermal
KW - Copper
PY - 2022
AN - OPUS4-55624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Influence Of Brine Precipitates On Materials Performance In Geothermal Applications
N2 - Significant Cu-deposition and precipitation only occurred in combination with carbon steel. High-alloyed materials prevent the disturbing Cu-agglomeration. Pb-deposition and precipitation only occurred in combination with carbon steel. No negative Pb-effect could be observed in combination with high-alloyed steels. High alloyed corrosion resistant alloys are suitable and shall be chosen for future design of the piping system, either in massive or in cladded form, to prevent unwanted interactions with brine components.
T2 - AMPP Annual 2023 Conference
CY - Denver, CO, USA
DA - 19.03.2023
KW - Geothermal
KW - Electrochemistry
KW - Copper
KW - Lead
KW - Corrosion
PY - 2023
AN - OPUS4-57237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Integrated Coating System for Corrosion Protection of Carbon Steel in Artificial Geothermal Brine
N2 - Corrosive geothermal brines are a major challenge to geothermal power-plants. For cost reasons, plant designers prefer to use carbon and low alloyed steels, which are susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic and saline properties. To solve such problem, coatings or inhibitors would be a protective solution as an alternative to the use of high alloyed materials.
This study investigated a coating system consisting of polyaniline/silicon dioxide based on resources locally available in Indonesia. Protection against corrosion of carbon steel was shown by long-term (28 day) exposure and electrochemical tests of coated carbon steels, performed in an artificial acidic and saline geothermal brine, comparable to the conditions encountered at a site in Indonesia.
Therefore, an integrated coating system is proposed for corrosion protection, combining the electrochemical functionality of polyaniline and the physical advantages of silica.
T2 - AMPP International Corrosion Conference 2022
CY - San Antonio, TX, USA
DA - 08.03.2022
KW - Geothermal
KW - Corrosion
KW - Coating
KW - Polyaniline
KW - Silicon dioxide
PY - 2022
AN - OPUS4-54452
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merino, E.
A1 - Cere, S.
A1 - Özcan Sandikcioglu, Özlem
A1 - Dimper, Matthias
A1 - Sobrados, I.
A1 - Durán, A.
A1 - Castro, Y.
T1 - Influence of the BF3·O(C2H5)2 on the corrosion resistance of hybrid silica sol-gel coatings deposited on flash-PEO-treated Mg alloy
N2 - Achieving highly cross-linked sol-gel coatings to provide effective corrosion protection of Mg alloys remains a challenging task. The aim of this work is to evaluate the effect boron trifluoride diethyl etherate (BF3·O(C2H5)2) as catalyst to epoxy group in a GPTMS/TEOS/SiO2 sol and assesses its effect on the structure and corrosion resistance properties of Flash-PEO coated pre-treated Mg alloy. 29Si MAS NMR and 13C CPMAS-NMR demonstrated that (BF3·O(C2H5)2) efficiently promotes the epoxy polymerization of the GPTMS and the formation of a hybrid silica network. However, the amount of (BF3·O(C2H5)2) should be optimized to minimize the formation of undesirable byproducts such as ethyl ether terminal units. Therefore, GPTMS/TEOS/SiO2 sols containing different amounts of (BF3·O(C2H5)2) were synthesized and deposited onto the Flash-PEO coated Mg alloy, leading to bilayer systems with a total thickness of ⁓8 μm. The corrosion behavior of the bilayer coatings in 3.5 wt% NaCl solution was evaluated by electrochemical impedance spectroscopy (EIS) and Scanning Kelvin probe microscope (SKPFM). The results revealed that the barrier properties of the coatings with enhanced cross-linked structure showed impedance modulus (│Z│f:0.1 Hz) approximately four orders of magnitude higher than the bare magnesium alloy and two orders of magnitude higher than the F-PEO coated sample. A suitable compromise between (BF3·O(C2H5)2) amount and sol-gel film structure is required to obtain a more durable barrier coating capable to extend the protective lifespan of the magnesium alloy.
KW - Sol-gel
KW - Corrosion
KW - AZ31B Mg alloy
KW - Chemical structure
KW - SKPFM
PY - 2026
DO - https://doi.org/10.1016/j.surfcoat.2025.133055
SN - 0257-8972
VL - 522
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - Exploration of Fe-Ni-Cr-X systems using diffusion couples for new alloy chemistries with improved mechanical and corrosion properties
N2 - Multi-principal element alloys (MPEAs) are disrupting methodologies in conventional alloy design, characterized by a singular dominant element dictating composition. The traditional optimization of the functional properties of alloys primarily relies on microalloying techniques. The advent of MPEAs has significantly broadened the chemical landscape available for exploration, approaching near-infinite possibilities. Consequently, innovative methodologies are imperative for discovering new alloys that exhibit properties customized for specific applications, simultaneously mitigating dependence on critical minerals. One promising approach for rapid screening of possible alloy chemistries and exploring the hitherto untouched regions of ternary, quaternary or higher order phase diagrams is the use of diffusion couples and multiples.
The present study focusses on the exploration of quaternary multi-principle-element alloys (MPEAs) using diffusion multiples. We established diffusion systems by combining an equimolar ternary alloy (FeNiCr) with single diffusing elements Mn, Mo and Ta. Using ThermoCalc® and DICTRA® simulations, we determined suitable parameters (temperature and diffusion time) that would lead to the formation of single-phase alloys and diffusion lengths (>50 μm) that suit the application of high-resolution characterization methods. Microstructural and compositional characterization was performed via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), electron probe microanalyzer (EPMA) and correlated to local mechanical properties evaluated by means of nanoindentation. Selected compositions
from the diffusion couples were recast and homogenized to obtain bulk samples for the assessment of high-temperature and aqueous corrosion properties.
Our results indicate that the ThermoCalc simulations have a good predictive power for crystallographic phases for Mn and Mo containing MPEAs derived from the diffusion couples. Moreover, our data on FeCrNi-Ta system provides valuable experimental input for respective databases necessary for simulation of phase diagrams.
The presentation will summarize our methodology using diffusion couples as an efficient tool for exploring compositional spaces of MPEAs in the search for novel alloy chemistries and the results of our correlative study on the mechanical and corrosion properties of the selected quaternary systems.
T2 - EUROCORR 2024
CY - Paris, France
DA - 01.09.2024
KW - CCMat
KW - Corrosion
KW - Diffusion couples
KW - Multi-principal element alloys
PY - 2024
AN - OPUS4-62634
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stohl, Leonie
A1 - Manninger, Tanja
A1 - von Werder, Julia
A1 - Dehn, F.
A1 - Gorbushina, Anna
A1 - Meng, Birgit
T1 - Bioreceptivity of concrete - A review
N2 - Materials that support natural biodiversity on their surfaces can compensate for human activities that have a negative impact on nature and thus contribute to a carbon-neutral and nature-positive world. Specifically designing bioreceptive materials which favor the growth of biofilms on their surface is an approach complementing conventional, macroscopic green façades. But what exactly characterizes a bioreceptive substrate and how do biofilm and substrate interact? How and why does a spontaneous colonization and the formation of biofilms take place? What are biofilms and how can they be established in a laboratory setting? How can this existing knowledge be transferred to the artificial stone concrete so that this material can be tuned to increase (or decrease) its bioreceptivity?
This review paper aims at summarizing the existing state of knowledge on bioreceptive concrete and pointing out inconsistencies and contradictions which can only be removed by more interdisciplinary research in the field.
KW - Bioreceptivity
KW - Biofilm
KW - Green facades
KW - Developing building materials
KW - Surface interactions
KW - Concrete
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581685
DO - https://doi.org/10.1016/j.jobe.2023.107201
SN - 2352-7102
VL - 76
SP - 1
EP - 17
PB - Elsevier
AN - OPUS4-58168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller-Elmau, Johanna
T1 - Transparent feedstocks for photon-based addiTve manufacturing technologies for powder processing of ceramics
N2 - Photon-based additive manufacturing technologies such as SLA, DLP, LCM, moreover volumetric two-photon-polymerization, Xolography and holographic technologies promise the highest accuracy and dimensional freedom. But to transfer the light through the feedstock it needs sufficient transparency at the used light wavelength. Ceramic particles used for powder processing routes act as scattering sites and therefore hinder the light transmission, unless…
The particle size and particle size distribution are chosen small and narrow enough. Particles which are smaller than roughly 1/10th of the light wavelength, mostly nanoparticles around 5nm size, decrease scattering vastly. This turns resins even with homogeneously distributed ceramic weight fraction of up to 80% transparent again. Feedstocks could be prepared for the highly accurate two-photon-polymerization gaining the smallest yttria stabilized zirconia structures with a resolution of 500nm and unique mechanical properties. The same feedstocks could be applied to DLP and LCM as layer-by-layer AM-technologies for bigger parts. Hybridizing both technologies lead to ceramic parts with microscopic accuracy at macroscopic dimensions. The feedstock was even applied to the volumetric Xolography with the highest transparency requirement so far and to versatile and flexible holographic AM.
Highly filled nano-particle containing transparent ceramic feedstocks open the way for technical ceramics in high precision manufacturing where the performance and durability and accessibility are increased and created by the unique ceramic properties such as mechanical strength, chemical and thermal resistance and biocompatibility
T2 - 2025 International Conference on Additive Manufacturing Technology Frontiers and Applications
CY - Xi'an, China
DA - 11.04.2025
KW - Tranparent
KW - Ceramic
KW - Additive manufacturing
PY - 2025
AN - OPUS4-65069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Wilbig, Janka
A1 - Waske, Anja
A1 - Günster, Jens
A1 - Widjaja, Martinus Putra
A1 - Neumann, C.
A1 - Clozel, M.
A1 - Meyer, A.
A1 - Ding, J.
A1 - Zhou, Z.
A1 - Tian, X.
T1 - Challenges in the Technology Development for Additive Manufacturing in Space
N2 - Instead of foreseeing and preparing for all possible scenarios of machine failures, accidents, and other challenges arising in space missions, it appears logical to take advantage of the flexibility of additive manufacturing for “in-space manufacturing” (ISM). Manned missions into space rely on complicated equipment, and their safe operation is a great challenge. Bearing in mind the absolute distance for manned missions to the Moon and Mars, the supply of spare parts for the repair and replacement of lost equipment via shipment from Earth would require too much time. With the high flexibility in design and the ability to manufacture ready-to-use components directly from a computer-aided model, additive manufacturing technologies appear to be extremely attractive in this context. Moreover, appropriate technologies are required for the manufacture of building habitats for extended stays of astronauts on the Moon and Mars, as well as material/feedstock. The capacities for sending equipment and material into space are not only very limited and costly, but also raise concerns regarding environmental issues on Earth. Accordingly, not all materials can be sent from Earth, and strategies for the use of in-situ resources, i.e., in-situ resource utilization (ISRU), are being
envisioned. For the manufacturing of both complex parts and equipment, as well as for large infrastructure, appropriate technologies for material processing in space need to be developed.
KW - Additive manufacturing
KW - Space
KW - Process
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549204
DO - https://doi.org/10.1016/j.cjmeam.2022.100018
SN - 2772-6657
VL - 1
IS - 1
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-54920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hmood, F. J.
A1 - Wilbig, Janka
A1 - Nicolaides, Dagmar
A1 - Zocca, Andrea
A1 - Günster, Jens
T1 - An approach to monitor the real-time deformation during heat treatment of 3D-printed glass
N2 - This study suggests a tool for a better control on the sintering/crystallization of 3D-printed bioactive glassceramics bodies. A small cantilever in form of a bar with square cross section attached to a base and inclined 34◦ with the horizon, was used to monitor the viscous flow and sintering/crystallization headway of a glassceramic systems. 3D printing and sintering of bioactive glass-ceramics is of great interest for medical care applications.
Viscous flow ensures sufficient densification of the typically low density printed green bodies, while crystallization prevents the structure from collapsing under the gravitational load. As a model system, a bioactive glass called BP1 (48.4 SiO2, 1 B2O3, 2 P2O5, 36.6 CaO, 6.6 K2O, 5.6 Na2O (mol%)), which has a chemical composition based on that of ICIE16, was employed in this work. In addition, ICIE16 was used as a reference glass. The results show that the suggested design is a very promising tool to track the real-time deformation of 3D printed glass-ceramic specimens and gives a good indication for the onset of crystallization as well.
KW - Real-time deformation
KW - Sintering
KW - 3D-printing
KW - Bioactive glass
PY - 2021
DO - https://doi.org/10.1016/j.ceramint.2021.03.334
VL - 47
IS - 14
SP - 20045
EP - 20050
PB - Elsevier Ltd.
AN - OPUS4-53449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Magnesium and its Alloys – Technology and Applications
N2 - The first edition of this book, published within the series “Materials Science – Metals and Alloys”, provides broad knowledge of this interesting and widely applied metal from manufacturing and production to finishing and application in 13 chapters, written by 29 contributors. Each chapter is separately concluded and ends with references used.
This book fulfills its intention of conveying comprehensive and cutting‐edge knowledge of magnesium alloys. It is useful for practicing engineers, researchers and students searching for an instructional and reference source.
KW - Magnesium
KW - Magnesium Alloy
PY - 2020
DO - https://doi.org/10.1002/maco.202070074
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 7
SP - 1229
EP - 1230
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - Additive Manufacturing of advanced ceramics by layerwise slurry deposition and binder jetting (LSD-print)
N2 - Powder bed technologies are amongst the most successful Additive Manufacturing (AM) techniques. Powder bed fusion and binder jetting especially are leading AM technologies for metals and polymers, thanks to their high productivity and scalability.
The application of these techniques to most ceramics has been difficult so far, because of the challenges related to the deposition of homogeneous powder layers when using fine powders.
In this context, the "layerwise slurry deposition" (LSD) has been developed as a layer deposition method which enables the use of powder bed AM technologies also for advanced ceramic materials. The layerwise slurry deposition consists of the layer-by-layer deposition of a ceramic slurry by means of a doctor blade, in which the slurry is deposited and dried to achieve a highly packed powder layer. This offers high flexibility in the ceramic feedstock used, especially concerning material and particle size.
The LSD technology can be combined with binder jetting to develop the so-called “LSDprint” process for the additive manufacturing of ceramics.
The LSDprint technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to those achieved by traditional processing.
In this presentation, the LSD process will be introduced and several examples of application ranging from silicate to high-performance ceramics will be shown.
Recent developments towards the scale-up and industrialization of this process will be discussed, alongside future perspectives for the multi-material additive manufacturing.
T2 - Ceramics in Europe 2022
CY - Krakow, Poland
DA - 10.07.2022
KW - Layerwise slurry deposition
KW - Laser induced slipcasting
KW - Additive Manufacturing
KW - Ceramics
PY - 2022
AN - OPUS4-55543
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neumann, Christian
A1 - Thore, Johannes
A1 - Clozel, Mélanie
A1 - Günster, Jens
A1 - Wilbig, Janka
A1 - Meyer, Andreas
T1 - Additive manufacturing of metallic glass from powder in space
N2 - Additive manufacturing of metals – and in particular building with laser-based powder bed fusion – is highly flexible and allows high-resolution features and feedstock savings. Meanwhile, though space stations in low Earth orbit are established, a set of visits to the Moon have been performed, and humankind can send out rovers to explore Venus and Mars, none of these milestone missions is equipped with technology to manufacture functional metallic parts or tools in space. In order to advance space exploration to long-term missions beyond low Earth orbit, it will be crucial to develop and employ technology for in-space manufacturing (ISM) and in-situ resource utilisation (ISRU). To use the advantages of laser-based powder bed fusion in these endeavours, the challenge of powder handling in microgravity must be met. Here we present a device capable of building parts using metallic powders in microgravity. This was proven on several sounding rocket flights, on which occasions Zr-based metallic glass parts produced by additive manufacturing in space were built. The findings of this work demonstrate that building parts using powder feedstock, which is more compact to transport into space than wire, is possible in microgravity environments. This thus significantly advances ISRU and ISM and paves the way for future tests in prolonged microgravity settings.
KW - Metallic Glass
KW - Additive Manufacturing
KW - Space
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600667
DO - https://doi.org/10.1038/s41526-023-00327-7
VL - 9
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-60066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Dense Powder Beds for the Additive Manufacturing of Ceramics
N2 - Regarding feedstocks for the additive manufacturing (AM) of ceramics, two features are most critical in classical powder based AM processes: a high particle packing density (typically >50% TD) must be achieved with very fine particles (typically submicron) in order to ensure sufficient sintering activity. Three innovative approaches will be introduced to overcome this problem:
1. Layer wise slurry deposition: The use of water based ceramic slurries as feedstock for the additive manufacture of ceramics has many advantages which are not fully exploit yet. In the layerwise slurry deposition (LSD) process a slurry with no or low organic content is repetitively spread as thin layers on each other by means of a doctor blade. During the deposition, the ceramic particles settle on the previously deposited and dried material to form thin layers with a high packing density (55-60%). The LSD therefore shares aspects both of tape casting and slip casting. The LSD differentiates from the classical powder-based AM layer deposition, which typically achieves with a flowable coarse grained powder a low packing density (35-50%) only, consequently hindering the ability of sintering ceramic parts to full density. The LSD is coupled with the principles of selective laser sintering (SLS) or binder jetting, to generate novel processes which take advantage of the possibility of achieving a highly dense powder-bed.
2. Laser induced slip casting: Contrary to the LSD process, which requires drying of each individual layer, the direct interaction of ceramic slurries with intense laser radiation, for the laser induced slip casting (LIS), is a promising approach for the additive manufacture of voluminous parts.
3. Gas flow assisted powder deposition: By the application of a vacuum pump a gas flow is realized throughout the powder bed. This gas flow stabilizes the powder bed and results into an enhanced flowability and packing density of the powder during layer deposition.
The presentation will provide a detailed discussion of potentialities and issues connected to the mentioned technologies and will describe the most recent developments in their application to technical ceramics.
T2 - SmatMade 2022
CY - Osaka, Japan
DA - 25.10.2022
KW - Additive Manufacturing
KW - Advanced ceramics
PY - 2022
AN - OPUS4-59886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - Material acceleration platforms (MAPs) - Global activities and developments at BAM
N2 - Die Material Acceleration Platform der BAM (MAPz@BAM) bündelt unsere Automatisierungs-Expertise auf dem Gebiet der Materialwissenschaft und -prüfung. Wir entwickeln modulare Experimentmodule, automatische Prüf- und Auswerteverfahren und setzen künstliche Intelligenz für eine effiziente und autonome Versuchsplanung, - vorhersage und Datenanalyse ein.
T2 - WPFM Expert Group on Structural Materials (EGSM)
CY - Online meeting
DA - 23.05.2023
KW - Material Acceleration Platforms (MAPs)
KW - MAPz@BAM
KW - Self-driving-labs
PY - 2023
AN - OPUS4-59409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diener, S.
A1 - Schubert, Hendrik
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Ink development for the additive manufacturing of strong green parts by layerwise slurry deposition (LSD-print)
N2 - Obtaining dense fine ceramics by the binder jetting additive manufacturing process is challenging. A slurry-based binder jetting process, such as the layerwise slurry deposition (LSD-print) process, can enable the printing of dense ceramic parts. This work describes a procedure to develop and qualify a suitable ink to manufacture silicon carbide green parts by LSD-print. Not only the printability but also the compatibility of the ink with the powder bed and the effect of the binding agent on the properties of the green parts are considered. Both aspects are important to obtain high green strength, which is necessary for printing large or thin-walled parts. Characterization methods, such as rheological and surface tension measurements, are applied to optimize three selected inks. The interplay between ink and powder bed is tested by contact angle measurements and by comparing the biaxial strength of cast and additively manufactured specimens.
Out of the three binding agents tested, a polyethyleneimine and a phenolic resin have a high potential for their use in the LSD-print of silicon carbide green bodies, whereas a polyacrylate binding agent did not show the required properties.
KW - Silicon carbide
KW - Binders/binding
KW - Inkjet
KW - Printing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567911
DO - https://doi.org/10.1111/jace.18951
SN - 0002-7820
SP - 1
EP - 12
PB - Wiley online library
AN - OPUS4-56791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Corrosion Atlas Case Studies - 2019 Edition
N2 - This edition, published as first issue within the series “Corrosion Atlas”, provides 181 corrosion case studies, collected from 29 contributors.
These Corrosion Atlas Case Studies provide a helpful tool required for engineers in their daily life to quickly determine and solve their equipment's corrosion problems by compact theoretical background and vivid examples. It fulfills the intension of the editors to be “the first centralized collection of case studies containing challenges paired directly with solutions together in one location”.
KW - Corrosion
KW - Failure
KW - Water-bearing
PY - 2020
DO - https://doi.org/10.1002/maco.202070054
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 5
SP - 859
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fornacon-Wood, Christoph
A1 - Stühler, Merlin R.
A1 - Millanvois, Alexandre
A1 - Steiner, Luca
A1 - Weimann, Christiane
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
A1 - Paulus, Beate
A1 - Plajer, Alex J.
T1 - Fluoride recovery in degradable fluorinated polyesters
N2 - We report a new class of degradable fluorinated polymers through
the copolymerization of tetrafluorophthalic anhydride and propylene
oxide or trifluoropropylene oxide which show up to 20 times
quicker degradation than the non-fluorinated equivalents and allow
for fluoride recovery.
KW - Fluoropolymers
KW - Recycling
KW - PFAS
KW - AFM force distance curves
KW - AFM plastic deformation
KW - AFM friction analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606768
DO - https://doi.org/10.1039/d4cc02513j
VL - 60
SP - 7479
EP - 7482
PB - Royal Society of Chemistry
AN - OPUS4-60676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmed, A. A. A.
A1 - Alegret, N.
A1 - Almeida, B.
A1 - Alvarez-Puebla, R.
A1 - Andrews, A. M.
A1 - Ballerini, L.
A1 - Barrios-Capuchino, J. J.
A1 - Becker, C.
A1 - Blick, R. H.
A1 - Bonakdar, S.
A1 - Chakraborty, I.
A1 - Chen, X.
A1 - Cheon, J.
A1 - Chilla, G.
A1 - Conceicao, A. L. C.
A1 - Delehanty, J.
A1 - Dulle, M.
A1 - Efros, A. L.
A1 - Epple, M.
A1 - Fedyk, M.
A1 - Feliu, N.
A1 - Feng, M.
A1 - Fernandez-Chacon, R.
A1 - Fernandez-Cuesta, I.
A1 - Fertig, N.
A1 - Förster, S.
A1 - Garrido, J. A.
A1 - George, M.
A1 - Guse, A. H.
A1 - Hampp, N.
A1 - Harberts, J.
A1 - Han, J.
A1 - Heekeren, H. R.
A1 - Hofmann, U. G.
A1 - Holzapfel, M.
A1 - Hosseinkazemi, H.
A1 - Huang, Y.
A1 - Huber, P.
A1 - Hyeon, T.
A1 - Ingebrandt, S.
A1 - Ienca, M.
A1 - Iske, A.
A1 - Kang, Y.
A1 - Kasieczka, G.
A1 - Kim, D.-H.
A1 - Kostarelos, K.
A1 - Lee, J.-H.
A1 - Lin, K.-W.
A1 - Liu, S.
A1 - Liu, X.
A1 - Liu, Y.
A1 - Lohr, C.
A1 - Mailänder, V.
A1 - Maffongelli, L.
A1 - Megahed, S.
A1 - Mews, A.
A1 - Mutas, M.
A1 - Nack, L.
A1 - Nakatsuka, N.
A1 - Oertner, T. G.
A1 - Offenhäusser, A.
A1 - Oheim, M.
A1 - Otange, B.
A1 - Otto, F.
A1 - Patrono, E.
A1 - Peng, B.
A1 - Picchiotti, A.
A1 - Pierini, F.
A1 - Pötter-Nerger, M.
A1 - Pozzi, M.
A1 - Pralle, A.
A1 - Prato, M.
A1 - Qi, B.
A1 - Ramos-Cabrer, P.
A1 - Resch-Genger, Ute
A1 - Ritter, N.
A1 - Rittner, M.
A1 - Roy, S.
A1 - Santoro, F.
A1 - Schuck, N. W.
A1 - Schulz, F.
A1 - Seker, E.
A1 - Skiba, M.
A1 - Sosniok, M.
A1 - Stephan, H.
A1 - Wang, R.
A1 - Wang, T.
A1 - Wegner, Karl David
A1 - Weiss, P. S.
A1 - Xu, M.
A1 - Yang, C.
A1 - Zargarin, S. S.
A1 - Zeng, Y.
A1 - Zhou, Y.
A1 - Zhu, D.
A1 - Zierold, R.
A1 - Parak, W. J.
T1 - Interfacing with the Brain: How Nanotechnology Can Contribute
N2 - Interfacing artificial devices with the human brain is the central goal of neurotechnology. Yet, our imaginations are often limited by currently available paradigms and technologies. Suggestions for brain−machine interfaces have changed over time, along with the available technology.
Mechanical levers and cable winches were used to move parts of the brain during the mechanical age. Sophisticated electronic wiring and remote control have arisen during the electronic age, ultimately leading to plug-and-play computer interfaces. Nonetheless, our brains are so complex that these visions, until recently, largely remained unreachable dreams. The general problem, thus far, is that most of our technology is mechanically and/or electrically engineered, whereas the brain is a living, dynamic entity. As a result, these worlds are difficult to interface with one another. Nanotechnology, which encompasses engineered solid-state objects and integrated circuits, excels at small length scales of single to a few hundred nanometers and, thus, matches the sizes of biomolecules, biomolecular assemblies, and parts of cells. Consequently, we envision nanomaterials and nanotools as opportunities to interface with the brain in alternative ways. Here, we review the existing literature on the use of nanotechnology in brain−machine interfaces and look forward in discussing perspectives and limitations based on the authors’ expertise across a range of complementary disciplines from neuroscience, engineering, physics, and chemistry to biology and medicine, computer science and mathematics, and social science and jurisprudence. We focus on nanotechnology but also include information from related fields when useful and complementary.
KW - Nanoneuro interface
KW - Brain-on-a-chip
KW - Nanostructured interface
KW - Electrode arrays
KW - Neuro-implants
KW - Advanced nanomaterials
KW - Quality assurance
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634893
DO - https://doi.org/10.1021/acsnano.4c10525
SN - 1936-086X
VL - 19
IS - 11
SP - 10630
EP - 10717
PB - ACS Publications
AN - OPUS4-63489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan, Jenny
A1 - Stühler, Merlin R.
A1 - Fornacon-Wood, Christoph
A1 - Dimde, Mathias
A1 - Ludwig, Kai
A1 - Sturm, Heinz
A1 - Olmedo-Martínez, Jorge L.
A1 - Müller, Alejandro J.
A1 - Plajer, Alex J.
T1 - Sulfur-containing block polymers from ring-opening copolymerization: coordinative encapsulants for transition metals
N2 - Sulfur-containing polymers can coordinate transition metals via sulfur-centered, chemically soft lone pairs, although this typically occurs in a spatially uncontrolled manner. In this study, we employed the controlled ring-opening copolymerization of oxetane with sulfur-containing comonomers to construct a series of amphiphilic block copolymers featuring thioester and thiocarbonate functionalities. These copolymers self-assemble in aqueous solution into aggregates with a sulfur-rich core capable of coordinating transition metals. This behavior could be resolved by employing cryo-transmission electron tomography and then extended to complexes incorporating functional coligands. Our study demonstrates how selective catalysis can be harnessed to produce functional polymers with tunable metal coordination properties, paving the way for an emerging class of sulfur-containing copolymers.
KW - Sulfur-containing polymer
KW - Controlled synthesis
KW - Metal ion coordination
KW - Cryo TEM
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626157
DO - https://doi.org/10.1039/d4py01415d
SN - 1759-9962
VL - 16
IS - 8
SP - 1003
EP - 1009
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62615
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Dahshan, O.
A1 - Deniaud, A.
A1 - Ling, W. L.
A1 - Wegner, Karl David
A1 - Proux, O.
A1 - Veronesi, G.
A1 - Reiss, P.
T1 - Hydrothermal microwave synthesis of water soluble NIR-II emitting Ag2S quantum dots
N2 - Hydrothermal-based synthetic methods of quantum dots allow for the exploration of reaction parameters normally inaccessible to typical aqueous-based batch reactions, such as elevated reaction temperatures (>100 °C) and reaction pressures above atmospheric pressure. Coupled with microwave heating, new instantaneously bio-compatible quantum dots (QDs) with enhanced opitcal properties can be yielded. As of today, aqueous-based synthetic methods often lag behind their organic analogues in terms of the photophysical properties of the QDs obtained and the ease of modulation of both the emission wavelength and crystallite size. Using a novel microwave-assisted hydrothermal approach, the synthesis of silver sulphide (Ag2S) QDs exhibiting NIR emission spanning the biological transparency windows via modulation of the reaction parameters has been developed. The intrinsic link between their optical and structural properties is explored via laboratory and synchrotron-based structural analysis techniques. Their toxicity towards a hepatic cell line was assessed, and related back to their structure and size. Overall this work aims to not only further develop the repertoire of synthetic methods for the synthesis of Ag2S QDs, but also paves the way for the development of safer QDs suitable for future clinical applications.
KW - Quantum dots
KW - Microwave synthesis
KW - Quality assurance
KW - NIR-II emission
KW - PL quantum yield
KW - Ag2S
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634825
DO - https://doi.org/10.1039/d5nr00052a
SN - 2040-3372
VL - 17
IS - 24
SP - 14637
EP - 14646
PB - RSC
AN - OPUS4-63482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Campbell, C. G.
A1 - Jordon Astorga, D.
A1 - Dümichen, Erik
A1 - Celina, M.
T1 - Thermoset materials characterization by thermal desorption or pyrolysis based gas chromatography-mass spectrometry methods
N2 - Thermoset materials characterization is often limited to solid state analytical techniques such as IR, NMR, DSC, TGA and mechanical testing. Alternatively, their off-gassing behavior can also be evaluated using GC based techniques such as TD-GC-MS, allowing this method to be applied to thermoset materials analyses such as identification, aging characterization, and formulation optimization. As an overview, common thermoset materials were evaluated by analyzing their gaseous degradation products via TGA-based pyrolysis and subsequent TD-GC-MS for the identification of representative volatile signatures. It is thereby possible to distinguish different classes of phenolic materials or cured epoxy resins, as well as their amine or anhydride curatives. Additionally, this method enabled quantification of a volatile fragment (bisphenol A, BPA) which is associated with oxidation of epoxy/amine thermoset materials. The amount of evolved BPA increased linearly with aging time and this trend exhibits linear Arrhenius behavior over the temperature range (80–125 °C) studied, in agreement with oxidation sensitivies based on oxygen consumption data. Further, TD-GC-MS was used to explore how off-gassing of residual anhydride curative from an epoxy/anhydride material depends on formulation stoichiometry. Even in formulations that theoretically contained enough epoxy to consume all anhydride (1:1 stoichiometry), an imperfect final cure state resulted in residual anhydride which could evolve from the material. For such materials, a slightly epoxy-rich formulation is required to ensure that the material contains no residual unreacted anhydride. Analysis of volatiles generated by thermal exposure is an attractive characterization approach enabling compositional analysis as well as complementary diagnostics for materials degradation.
KW - Polymer analysis/characterization
KW - Thermal desorption mass spectrometry
KW - Thermoset composition
KW - Volatiles from thermosets
KW - Degradation signatures
PY - 2020
DO - https://doi.org/10.1016/j.polymdegradstab.2019.109032
VL - 174
SP - 109032
PB - Elsevier Ltd.
AN - OPUS4-50435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Cano Murillo, Natalia
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Hahn, Marc Benjamin
A1 - Hodoroaba, Vasile-Dan
A1 - Sturm, Heinz
T1 - Cover image for the article "Nanomechanical study of polycarbonate/boehmite nanoparticles/epoxy ternary composite and their interphases"
N2 - The image designed by Natalia Cano Murillo and colleagues shows the cross section of a ternary composite (boehmite/polycarbonate/epoxy, 80μm x 80μm). The surface was measured by AFM kelvin probe microscopy, yielding the surface potential which is shown as 3D‐surface and contour lines. The sample was further subjected to AFM force spectroscopy with a lateral resolution of 1μm², yielding the local Young's modulus, projected in false colors on the 3D surface. The ternary system, containing boehmite nanoparticles, shows a broad distribution of modulus, desirable for optimized macroscopic mechanical properties, such as high stiffness as well as toughness.
KW - Boehmite
KW - Epoxy
KW - Polycarbonate
KW - AFM
KW - BNP
PY - 2020
DO - https://doi.org/10.1002/app.50400
SN - 0021-8995
SN - 1097-4628
VL - 138
IS - 12
SP - 1
PB - Wiley
CY - New York, NY
AN - OPUS4-51831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nakadi, Flavio V.
T1 - Single-event analysis of discrete entities using microwave-induced nitrogen plasma–mass spectrometry
N2 - ICP-MS has become a standard for (ultra)trace elemental analysis due to its excellent sensitivity and multi-element capabilities. However, its widespread use is hampered by spectral interferences—especially in the low mass range (<81 amu)—primarily arising from Ar-based polyatomic ions, such as ArO+ and Ar2+, which compromise the accurate quantification of key elements like Fe and Se.1 Over the years, improvements such as collision/reaction cells and sector-field configurations have
helped mitigate these interferences, albeit often at the cost of instrument complexity and increased operational burden.The microwave-induced nitrogen plasma (MINP) source, sustained by microwaves at atmospheric pressure and using nitrogen as the plasma gas, offers a fundamentally different plasma environment. Nitrogen is not only more economical (40-60%) and readily available than Ar, but also avoids the generation of problematic Ar-based interferences. While MINP had been previously applied in optical emission and bulk mass spectrometry,2 its implementation in single-event detection had not yet been demonstrated.
This study pioneers the application of MINP-MS in single-event mode for real-time, high-throughput characterization of NPs, cells, and MPs. The evaluation began with Fe2O3 NPs monitoring the 56Fe nuclide, with a limit of detection of 8.6 ag for Fe, equivalent to a particle size threshold of 19 nm—surpassing the detection capabilities of quadrupole-based ICP-MS systems. Size distribution results
obtained by SP-MINP-MS for Fe2O3 NPs (20–70 nm) matched closely with transmission electron microscopy (TEM) and dynamic light scattering (DLS), confirming the method’s accuracy.
For Se, despite its high ionization energy, metallic SeNPs (150 and 250 nm) were reliably quantified by monitoring 80Se. A calibration curve constructed using SeNP standards yielded excellent linearity (R2 = 0.9994). This approach was further extended to single-cell analysis, using Se-enriched yeast (SELM-1 CRM) as a model. A transport efficiency-independent calibration strategy was employed, relying on SeNPs to determine Se content per cell. The results showed strong agreement with data from conventional SC-ICP-MS, with average Se masses of ~65 fg per cell, validating the
performance of SC-MINP-MS for biological systems. Additionally, the instrument's capability to handle large, low atomic number particles was demonstrated via the analysis of polystyrene (PS) and polytetrafluoroethylene (PTFE) MPs. These MPs (2.5–3.0 µm) were quantified by monitoring 12C+ signals and applying a calibration strategy using citric acid as a standard. The resulting size distributions closely matched nominal sizes, reinforcing the system’s robustness for micrometer-sized polymeric materials. Event durations ranging from 470 to over 900 µs were consistent with literature values for single-entity ICP-MS and correlated well with particle size.
These findings establish single-event MINP-MS as a promising analytical platform for analyzing discrete entities. It provides significant advantages over conventional Ar-based ICP-MS, including reduced interferences, lower operational cost, and comparable or superior sensitivity for analytes such as Fe and Se. By avoiding the limitations of Ar-based plasmas and enabling accurate quantification across a wide range of particle types and sizes, MINP-MS in single-event mode opens new avenues for high-resolution, interference-free elemental analysis at the individual entity level.
T2 - 17th Rio Symposium on Atomic Spectrometry (17th RSAS)
CY - São Pedro City, Brazil
DA - 09.11.2025
KW - MICAP-MS
KW - Nitrogen plasma
KW - Nanoparticles
KW - Cells
KW - Microplastic
KW - Single particle
KW - Single event
KW - ICP-MS
PY - 2025
AN - OPUS4-64954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Barkeshli, Mandana
A1 - Stephan, Ina
A1 - Shevchuk, Ivan
A1 - Soltani, Mojtaba
T1 - Characteristics of Sizing Materials Used in Persian Medieval Manuscripts: Physical, Optical, Spectral Imaging, and Fungicidal Properties
N2 - In this study, we investigated the diverse range of materials used for sizing in Iranian paper manuscripts during the Timurid (fifteenth century) to Safavid (sixteenth century) and Qajar (nineteenth century) periods. Our approach combined historical analysis with scientific examination of reconstructed sizings. We reconstructed 15 sizing materials based on identified Persian historical recipes and analysed their physical, optical, and spectral characteristics. Additionally, we assessed their behaviour against the mould fungus Aspergillus flavus. The results revealed distinctive properties for each sizing material, shedding light on their potential applications in paper preservation. Furthermore, our investigation demonstrated variations in hygroscopicity, thickness, grammage, and ash content post-sizing. The sizing materials also exhibited different effects on paper reflectance properties. Additionally, our study revealed insights into the impact of sizing on burnished papers, indicating that the mechanical process of burnishing did not significantly alter the chemical composition or spectral properties of the paper, with only minor changes in brightness observed in specific cases. All tested sizing materials supported varying levels of mould growth, indicating potential implications for paper conservation. Our findings provide valuable insights into the historical practices of Iranian paper sizing and offer practical considerations for the preservation of paper manuscripts.
KW - Paper sizings
KW - Persian historical recipes
KW - Physical and optical characteristics
KW - Fungicidal property
KW - Spectral imaging
PY - 2024
DO - https://doi.org/10.1080/00393630.2024.2342647
VL - 69
SP - 519
EP - 536
PB - Informa UK Limited
AN - OPUS4-60159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Topolniak, Ievgeniia
T1 - Micropatterning of mussel-inspired materials - Empower selective functionality
N2 - Surface-modification platforms that are universally applicable are vital for the development of new materials, surfaces, and nanoparticles. Mussel-inspired materials (MIMs) are widely used in various fields because of their strong adhesive properties and post-functionalization reactivity. However, conventional MIM coating techniques have limited deposition selectivity and lack structural control, which has limited their use in microdevices that require full control over deposition. To overcome these limitations, we developed a micropatterning technique for MIMs using multiphoton lithography, which does not require photomasks, stamps, or multistep procedures. This method enables the creation of MIM patterns with micrometer resolution and full design freedom and paves the way for innovative applications of MIMs in various multifunctional systems and microdevices, such as microsensors, MEMS, and microfluidics.
T2 - BioCHIP Berlin - International Forum on Biochips and Microfabrication
CY - Berlin, Germany
DA - 28.05.2024
KW - Mussel inspired materials
KW - Multiphoton lithography
KW - Two photon polymerisation
PY - 2024
AN - OPUS4-60254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Stephan, Ina
A1 - Boenke, Viola
A1 - Drecker, Sigrid
T1 - Weiterentwicklung und Verbesserung des Konzeptes zur Begrenzung von Konservierungsmitteln für Produkte mit dem Blauen Engel
N2 - Im Rahmen des Forschungsvorhabens wurde die biologische Prüfmethode der Checkliste zur stoffli-chen Bewertung im Rahmen des Aufnahmeverfahrens für weitere Topfkonservierungsmittel in den Anhang 1 zur Vergabegrundlage RAL-UZ102 „Emissionsarme Innenwandfarben“ überarbeitet. Der Test für den Einsatz von Konservierungsmitteln in seiner jetzigen Fassung besteht seit nahezu 20 Jah-ren und erfolgt ausschließlich an weißer Dispersionsfarbe für den Innenraum. Die hierbei ermittelten Höchstmengen für den Einsatz von Topfkonservierern werden z.Zt. auch auf andere Innenraumbau-produkte übertragen. Ziel war es zu klären, ob die Anforderungen an die Topfkonservierung bei Far-ben tatsächlich für andere Innenraumbauprodukte übernommen werden können. Die im Vorhaben durchgeführten Versuche deuten darauf hin, dass dies nicht ohne weiteres möglich ist. Nach Rückspra-che mit Vertretern aus der Industrie wurde das Keimspektrum für die Prüfung zudem um Hefe- und Schimmelpilze erweitert. Des Weiteren wurde eine künstliche Alterung eingeführt und überprüft, ob dies einen Einfluss auf den Gehalt an Isothiazolinonen hat. Die Konzentration von Isothialzolinonen wurde mittels Ultra-Hochleistungsflüssigkeitschromatographie kontrolliert und hinsichtlich einer Kor-relation mit dem Wachstum von Mikroorganismen ausgewertet. Da die in den Innenraumbauproduk-ten zugesetzten Isothiazolinone als Kontaktallergene bekannt sind, ist es ein Ziel des „Blauen Engel“-Umweltzeichens, die geringste erforderliche Menge an Konservierungsmittel in den Produkten zu ver-wenden, ohne die positive Auswirkung der Topfkonservierung zu gefährden. Daher sind die Optimie-rung der Leistungsstärke von Konservierungsmitteln und die Kontrolle der Hygiene im Herstellungs-prozess von zunehmender Bedeutung. Um Einblicke in den Herstellungsprozess von Farben zu gewin-nen, wurden im Rahmen des Vorhabens vier Farbwerke besichtigt, in denen weiße Innenraumfarben produziert werden, die mit dem Umweltzeichen „Blauer Engel“ ausgezeichnet sind. Gemeinsam mit den Fachleuten vor Ort wurde diskutiert, welche Maßnahmen zur Verbesserung der Werkshygiene er-griffen werden können, um den Einsatz von Topfkonservierern möglichst gering zu halten. Des Weite-ren wurde in dem Forschungsvorhaben untersucht, ob eine schnellere Bestimmung der Keimzahl in den Rohstoffen mittels quantitativer Polymerasekettenreaktion bereits im Farbwerk realisierbar ist.
KW - Methode
KW - Isothiazolinone
KW - Gebindekonservierung
KW - Bakterien
KW - Schimmel
KW - Wirksamkeit
KW - Biozide
PY - 2020
SN - 1862-4804
VL - 54
SP - 4
EP - 149
PB - Umweltbundesamt
CY - Dessau
AN - OPUS4-50972
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan, Ina
A1 - Dimke, Thomas
A1 - Guterman, R.
A1 - Smith, C. A.
A1 - Cataldo, V. A.
T1 - Antibacterial and degradable thioimidazolium poly(ionic liquid)
N2 - New antibacterial agents are urgently required to fight the emergence of antibiotic-resistant bacteria. We recently synthesized the first thioimidazolium ionene, which has antibacterial properties and can degrade in various media. This dual functionality is crucial in order to limit the environmental impact of these biocides. We have found that our polymer is stronger than benzalkonium chloride (BAC) against Pseudomonas aeruginosa and also readily degrades in the presence of base, while remaining stable in acidic environments. These results highlight a new emerging class of antibacterial degradable polymers.
KW - Ionic liquid
KW - Antibacterial polymer
KW - Amphiphilic polymer
KW - Thioimidazolium
KW - Degradable polymer
KW - Polyioinic liquid
PY - 2020
DO - https://doi.org/10.1021/acssuschemeng.0c02666
VL - 8
IS - 22
SP - 8419
EP - 8424
PB - ACS Publications
AN - OPUS4-50982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valet, Svenja
A1 - Bohlmann, Tatjana
A1 - Ebell, Gino
A1 - Burkert, Andreas
T1 - pH sensitive gel pads for the visualization of anodes and cathodes on zinc
N2 - Zinc and zinc alloys have many applications. Zinc corrosion takes place in the atmosphere and is assumed to follow the water drop theory (a macroelement), in which the anode is at the centre of the drop and is surrounded by a cathode. This paper is the first to use gel electrolytes made of agar to visualize anodic and cathodic areas on zinc samples in order to examine the water drop theory. For that, agar gels were added with universal pH indicators, as the anode and cathode exhibit different pH values. In this paper, different amounts of pH indicators were tested to determine whether the indicator influences the potential, the impedance, phase shift, corrosion current and potential and corrosion layer resistance.
KW - Corrosion
KW - Zinc
KW - Gel electrolyte
PY - 2026
DO - https://doi.org/10.1016/j.electacta.2026.148134
SN - 0013-4686
VL - 551
SP - 1
EP - 21
PB - Elsevier Ltd.
AN - OPUS4-65308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burkert, Andreas
T1 - Grundlagen Spannungsrisskorrosion
N2 - Der Vortrag stellt die Grundlagen und Schädigungsmechanismen der Spannungsrisskorrosion an metallenen Werkstoffen vor. Aus dem Zusammenspiel von mechanischer Beanspruchung, dem Korrosionsmedium und den Eigenschaften des Werkstoffs können sich Bedingungen ergeben, welche den Eintritt von SpRK begünstigen können. Speziell wird auf auf die chloridinduzierte Spannungsrisskorrosion und die wasserstoffinduzierte SpRK näher eingegangen. Abschließend werden einige normative Prüfmöglichkeiten vorgestellt.
T2 - Korrsosionsschutz in der maritimen Technik
CY - Hamburg, Germany
DA - 28.01.2026
KW - Spannstahl
KW - Spannungsrisskorrosion
KW - Nichtrostender Stahl
KW - Korrosion
PY - 2026
AN - OPUS4-65425
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rurack, Knut
T1 - Functional polymeric coatings for sensory applications
N2 - The growing demand for the detection of relevant chemical compounds as close as possible to their point of origin—whether in industrial processes, for (civilian or military) security, or for environmental monitoring—has increased the importance of functional polymers with molecular recognition capabilities. These materials must meet practical requirements arising from very different real-world scenarios in which simple, robust, and field-deployable approaches are needed and in which bioanalytical binders often suffer significant performance losses. Polymer recognition matrices therefore serve as an essential complement to established laboratory-based analytical technologies.
The realization of rapid and reliable onsite detection places specific demands on material design: polymeric recognition layers must be produced with minimal thickness, integrated onto suitable carrier media, and designed for both selectivity and operational robustness. This presentation will introduce our work on molecularly imprinted polymers (MIPs) that have been specifically developed for the detection of relevant contaminants such as pesticides and perfluorinated compounds. Beyond these target analytes, the presentation will show how such polymer layers can support robust, sustainable diagnostic concepts, and it will outline generalizable design principles that enable their extension to a broad spectrum of analytical challenges.
T2 - Institutskolloquium des Instituts für Chemie, Humboldt Universität zu Berlin
CY - Berlin, Germany
DA - 28.01.2026
KW - Functional organic materials
KW - Responsive polymers
KW - Sensing
KW - Molecularly imprinted polymers
PY - 2026
AN - OPUS4-65435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gladrow, K.
A1 - Unkovskiy, A.
A1 - Yassine, J.
A1 - Gaertner, N.
A1 - Topolniak, Ievgeniia
A1 - Henning, N.
A1 - Schmidt, F.
T1 - The effect of nitrogen atmosphere during post-curing on cytotoxicity, polishability, flexural strength, and surface hardness of 3D-printed denture bases: an in vitro study
N2 - 3D printing is increasingly utilized in dentistry. Compared to traditional manufacturing methods, 3D printing provides advantages such as faster production times and the ability to create complex structures. Although biocompatible materials are available, many are only suitable for temporary applications. This study examines the impact of nitrogen-aided post-processing on the mechanical properties and cytotoxicity of 3D-printed denture bases, with the hypothesis that this post-processing will enhance material properties and decrease cytotoxicity. Specimens were fabricated from V-print dentbase (Voco GmbH, Cuxhaven, Germany) and post-processed either in nitrogen or air. The specimens were categorized into aged and non-aged groups. For comparison, specimens made from milled material were utilized. Vickers hardness, flexural strength, polishability, cytotoxicity, and degree of conversion were then assessed for all groups. The data were analyzed using a one-way ANOVA and Tukey HSD test for multiple comparisons, with a significance threshold of p < 0.05. Post-curing with nitrogen improved the degree of conversion, surface hardness, and biocompatibility of 3D-printed dental materials, confirming reduced cytotoxicity without impairing mechanical properties. Nitrogen increased polymerization and decreased harmful monomers, making it ideal for clinical applications in contact with the oral mucosa. Optimizing post-processing steps, such as curing in nitrogen, enhances biocompatibility while maintaining strength and hardness, ensuring better patient care in dental applications.
KW - Biocompatibility
KW - V-Print
KW - Cytotoxicity
KW - Nitrogen
KW - Dentistry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654504
DO - https://doi.org/10.1007/s10856-026-07006-5
SN - 1573-4838
VL - 37
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - The role of Critical Raw Materials in Advanced Materials for the Energy Transition
N2 - Based on the UBA report “Advanced materials for energy transition” by Xenia Knigge and Jörg Radnik the role of critical raw materials is discussed. Critical raw materials are needed in main fields of the energy transition, like photovoltaic, fuel cells, wind energy, and batteries. For the optimisation of the use of these materials different scenarios are discussed like (i) decreasing the needed amount of raw materials, (ii) searching for alternatives, (iii) using technologies which do not require critical raw materials, (iv) increasing the recycling rates, and (v) expanding the raw material sources.
T2 - IRISS policy dialogue
CY - Online meeting
DA - 12.01.2026
KW - Solar Cells
KW - Fuel cells
KW - Batteries
KW - Multi-use materials
PY - 2026
AN - OPUS4-65451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kleba-Ehrhardt, Rafael
A1 - Dávila, Josué
A1 - Geissler, Johann
A1 - Mohr, Gunther
A1 - Schmidt, Johannes
A1 - Heinze, Christoph
A1 - Hilgenberg, Kai
A1 - Gurlo, Aleksander
A1 - Karl, David
T1 - Influence of Haynes 282 powder oxidation on powder properties and component quality in laser powder bed fusion
N2 - Reuse of powder in powder bed additive manufacturing is a common practice to enhance sustainability and reduce costs. However, the reusability of metal powder is limited by the oxidation of the powders. Even in a protective atmosphere, each build job leads to gradual oxidation of the powder, which has led to concerns about its impact on powder and part properties. Consequently, strict confidence intervals for oxygen content in nickel-based alloy feedstocks are enforced in the industry. Despite this, there is currently a lack of in-depth studies investigating the specific influence of oxygen on Haynes 282, a widely used nickel-based alloy. This study examines artificially aged Haynes 282 powder batches with oxygen content of 160 ppm, 330 ppm, 1050 ppm, and 1420 ppm. Detailed powder characterization was performed, including morphology, chemical composition, particle size, flowability, and packing behavior. Components were fabricated via PBF-LB/M to evaluate density and mechanical properties. The results showed that higher oxidation levels improved powder flowability and packing density. However, in manufactured parts, irregular melt tracks and increased surface roughness were observed, which could easily be removed by post-processing. No significant differences in density or mechanical properties at room temperature, such as tensile strength and elongation, were found. These findings indicate that H282 powder potentially remains suitable for reuse, even when the batches exhibit increased oxygen content, supporting discussions on revising the existing oxygen content confidence intervals for nickel-based alloys. The results highlight the potential for optimizing recycling strategies and reducing material waste in additive manufacturing processes.
KW - Additive manufacturing
KW - Powder bed fusion
KW - Powder characterization
KW - Powder oxidation
KW - Powder recycling
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654545
DO - https://doi.org/10.1016/j.addma.2025.105050
SN - 2214-8604
VL - 116
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-65454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rahner, E.
A1 - Thiele, T.
A1 - Voss, Heike
A1 - Müller, F.A.
A1 - Bonse, Jörn
A1 - Gräf, S.
T1 - Objective, high-throughput regularity quantification of laser-induced periodic surface structures (LIPSS)
N2 - The growing demand for precise surface functionalization through laser-generated periodic surface structures highlights the necessity for efficient, reproducible, and objective evaluation methods to evaluate their structural regularity. We introduce ReguΛarity (v.1.2.7), a freely available, Python-based software with a graphical user interface for the automated, quantitative assessment of the regularity of laser-induced periodic surfaces structures (LIPSS), obtained from optical microscopy, SEM, or AFM. The software integrates image segmentation, one- and two-dimensional Fourier analyses, and gradient-based orientation determination to facilitate a comprehensive regularity analysis of grating-like (quasi-)periodic surface patterns with spatial periods Λ. This is achieved through the proposed regularity tuple R, composed of five key parameters: the normalized spread of the spatial period RΛ,2D (from 2D-FT), the normalized variation of the most frequent spatial period RΛ (from 1D-FT), the Gini coefficient G, the Dispersion of the LIPSS Orientation Angle δθ (DLOA), and the mean phase deviation . To demonstrate its applicability, we compare ideal sinusoidal patterns with SEM images obtained from LIPSS on stainless steel (AISI 316L) and aluminum alloy (AlMg5) surfaces, confirming the software’s ability to objectively distinguish between varying levels of structural regularity. ReguΛarity facilitates high-throughput analysis and data-driven process optimization in surface engineering and laser materials processing.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Image processing
KW - Regularity quantification
KW - Fourier analysis
KW - Structural homogeneity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654070
DO - https://doi.org/10.1016/j.apsusc.2026.165919
SN - 0169-4332
VL - 726
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-65407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z. C.
A1 - Haist, M.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Schmid, M.
A1 - Kißling, P. A.
A1 - Leinitz, Sarah
A1 - Link, J.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Plank, J.
A1 - Schmidt, Wolfram
A1 - Schilde, C.
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Stephan, D.
T1 - Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials"
N2 - Two types of cements were selected as the reference cement in the priority program 2005 of the German Research Foundation (DFG SPP 2005). A thorough characterization of CEM I 42.5 R has been made in a recent publication. In this paper, the characterization data of the other reference cement CEM III/A 42.5 N are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The characterization data of the slag, which is the second main constituent of this specific cement besides the clinker, are presented independently. For all data received, the mean values and the corresponding errors were calculated. The data shall be used for the ongoing research within the priority program. Also, researchers from outside this priority program can benefit from these data if the same materials are used.
KW - Cement
KW - Slag
KW - Characterization
KW - DFG SPP 2005
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568980
DO - https://doi.org/10.1016/j.dib.2020.105524
SN - 2352-3409
VL - 30
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schmidt, Wolfram
A1 - Tlhatlha, Pheladi
A1 - Obeng, Emmanuel
A1 - Tsaku, Mawuli Kwaku
A1 - Arthur, Daniel Vincent
A1 - Dodoo, Alex
ED - Schmidt, Wolfram
ED - Tlhatlha, Pheladi
T1 - A practical handbook for safe, smart and durable construction in Ghana
N2 - The handbook provides practical guidelines for safe, efficient, and effective construction in Ghana, focusing on proper cement use, mixing consistencies and techniques, and environmental protection. It emphasizes quality control, safety in handling construction materials, and the importance of using protective equipment to prevent health hazards.
KW - Cement strength classifications
KW - Cement mixing ratios
KW - Quality control
PY - 2025
SN - 978-3-00-083134-8
SP - 1
EP - 35
PB - Ghana Standards Authority (GSA)
CY - Accra
AN - OPUS4-63641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
T1 - Accelerating Sustainable Material Development with SLAMD: Case Studies Using Recycled and Bio-Based Materials
N2 - As part of the EU Reincarnate project, BAM has developed an AI-based tool that signifi-cantly accelerates the development of materials in an iterative process of laboratory work, experimental validation, and data-driven optimization. This approach has already been suc-cessfully tested and validated. In Reincarnate SLAMD is currently being applied in demon-stration projects together with two industrial partners – a recycling company specializing in construction and demolition waste and a leading supplier of cement-based building materi-als. The recycling company aims to process recycled concrete fines and glass waste into composite cements with improved performance characteristics. The building materials' manufacturer, on the other hand, aims to reuse processed concrete waste primarily as aggre-gate and to develop suitable materials for five different exposure classes. The integration of SLAMD is envisioned to enable the rapid identification of optimal material compositions that consider the performance and ecological and economic aspects.
In addition, we currently further develop in the Circular B-I/O project, a joint effort with African partners to develop alternative, more biobased building materials. The goal is to integrate agricultural residues – such as corn cobs, rice hulls, and sugarcane bagasse – into large-scale, robust supply chains for the construction industry. AI-driven decision-making will be used to create a sustainable framework to transform these seasonally variable raw materials into reliable, high-performance concrete components. Building stable ecosystems and supply chains is crucial to ensure the continuous availability of sustainable materials for a resilient and circular construction industry.
T2 - 2nd Net-zero-future Conference
CY - Cape Town, South Africa
DA - 05.11.2025
KW - Data-driven Design
KW - Sustainable Materials
KW - Recycling
PY - 2025
AN - OPUS4-64952
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schusterbauer, Robert
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Corrao, Elena
A1 - Zurutuza, Amaia
A1 - Doolin, Alexander
A1 - Pellegrino, Francesco
A1 - Radnik, Jörg
A1 - Donskyi, Ievgen S.
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative Chemical Imaging to Reveal the Nature of Different Commercial Graphene Materials
N2 - Proper physicochemical characterization of advanced materials and complex industrial composites remains a significant challenge, particularly for nanomaterials, whose nanoscale dimensions and mostly complex chemistry challenge the analysis. In this work, we employed a correlative analytical approach that integrates atomic force microscopy (AFM), scanning electron microscopy (SEM) coupled with energy‐dispersive X‐ray spectroscopy (EDS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), Auger electron spectroscopy (AES), and Raman spectroscopy. This combination enables detailed chemical and structural characterization with sub‐micrometer spatial resolution. Three commercial graphene‐based materials of varying complexity were selected and investigated to test the analytical performance of this approach. Furthermore, one of the commercial graphene oxide samples was chemically functionalized via amination and fluorination. This allowed us to assess how surface modifications influence both the material properties and the limits of the applied analytical techniques.
KW - Analytical methods
KW - Commercial products
KW - Correlative analysis
KW - Graphene
KW - Surface imaging
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654765
DO - https://doi.org/10.1002/smtd.202502344
SN - 2366-9608
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-65476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rizzardi, Q.
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - Intermittent microplasticity in the presence of a complex microstructure
N2 - We demonstrate the gradual shift from scale-free intermittent microplasticity to a scale-dependent behavior via the introduction of a variety of microstructural features within the Al-Cu binary alloy system. As long as the obstacles to dislocation motion remain shearable, the statistics of intermittent microplasticity has fat-tailed contributions. The introduction of incoherent precipitates leads to a complete transition from scale-free powerlaw scaling to an exponential and scale-dependent distribution. These results demonstrate how non-Gaussian interactions survive across different microstructures and further suggest that characteristic microstructural length scales and obstacle pinning-strengths are of secondary importance for the intermittency statistics, as long as dislocations can shear their local environment.
KW - Scale-dependent behavior
KW - Al-Cu binary alloy system
PY - 2022
DO - https://doi.org/10.1103/PhysRevMaterials.6.073602
SN - 2475-9953
VL - 6
IS - 7
SP - 1
EP - 9
PB - American Physical Society
AN - OPUS4-55387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallis, Theophilus
A1 - Darvishi Kamachali, Reza
T1 - Grain boundary structural variations amplify segregation transition and stabilize co-existing spinodal interfacial phases
N2 - Grain boundaries (GBs)’s role in determining the functional and mechanical properties of polycrystalline materials is inscribed in both their structure and chemistry. Upon solute segregation, the structure and composition of a GB can change concurrently. We study the co-evolution of GB’s structure and segregation by enhancing the density-based phase-field model to account for the in-plane structural variations in the GB. Significant mutual coupling is revealed between the GB’s chemical and structural states during Mn segregation in Fe-Mn alloys. We found that the structural degrees of freedom in a GB (the ability of the GB structure to respond to the chemical variation) amplifies Mn segregation transition, even when the GB structure stays unchanged. When the GB structure is not uniform, that is the usual case, the coupling between GB structure and segregation evolution also enables the spinodally formed low- and high-Mn phases (upon segregation transition) to co-exist within the GB region. These findings explain the stabilizing mechanism of pronounced interfacial segregation fluctuations, experimentally evidenced in Fe-Mn GBs, and give new insights on the structural sensitivity of GBs’ segregation phenomena and the mutual chemo-structural interplay.
KW - Grain boundary engineering
KW - Segregation engineering
KW - Grain boundary structure
KW - Fe-Mn steels
PY - 2022
DO - https://doi.org/10.1016/j.actamat.2022.118446
SN - 1359-6454
VL - 242
PB - Elsevier Ltd.
AN - OPUS4-56160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Derlet, P.
A1 - Bocquet, H.
A1 - Maaß, Robert
T1 - Viscosity and transport in a model fragile metallic glass
N2 - How thermally activated structural excitations quantitatively mediate transport and microplasticity in a model binary glass at the microsecond timescale is revealed using atomistic simulation. These local excitations, involving a stringlike sequence of atomic displacements, admit a far-field shear-stress signature and underlie the transport of free-volume and bond geometry. Such transport is found to correspond to the Evolution of a disclination network describing the spatial connectivity of topologically distinct bonding environments, demonstrating the important role of geometrical frustration in both glass structure and its underlying dynamics.
KW - Metallic glass
KW - Viscosity
PY - 2021
DO - https://doi.org/10.1103/PhysRevMaterials.5.125601
SN - 2475-9953
VL - 5
SP - 1
EP - 7
PB - American Physical Society
CY - College Park, MD
AN - OPUS4-54152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maximilian, Thuy
A1 - Spyrantis, Alexander
A1 - Böhning, Martin
A1 - Niebergall, Ute
A1 - Maaß, Robert
T1 - Spatially resolved roughness exponent in polymer fracture
N2 - The fracture surface of slow and continuous crack propagation during environmental stress cracking of a semicrystalline polyethylene exhibits isotropic roughness exponents at the local scale but resolved across the macroscopic fracture surface a clear position dependence is found. The spatially resolved roughness exponent admits values in the range between 0.1 and 0.4, demonstrating nontrivial exponents in the small length-scale regime. Instead, they vary across the fracture surface according to the stress-state distribution, which suggests that the exponents are intimately linked to the locally dominating dissipation processes during craze cracking.
KW - Plasticity
KW - Fracture
KW - Material failure
KW - Mechanical deformation
PY - 2022
DO - https://doi.org/10.1103/PhysRevMaterials.6.L090601
VL - 6
IS - 9
SP - 1
EP - 7
PB - American Physical Society
CY - USA, Maryland
AN - OPUS4-55797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shimada, Y.
A1 - Ikeda, Yuki
A1 - Yoshida, K.
A1 - Sato, M.
A1 - Chen, J.
A1 - Du, Y.
A1 - Inoue, K.
A1 - Maaß, Robert
A1 - Nagai, Y.
A1 - Konno, T.
T1 - In situ thermal annealing transmission electron microscopy of irradiation induced Fe nanoparticle precipitation in Fe–Si alloy
N2 - The typical experimental conditions inside a transmission electron microscope (TEM), such as ultra-high vacuum, high-energy electron irradiation, and surface effects of ultrathin TEM specimens, can be the origin of unexpected microstructural changes compared with that of bulk material during in situ thermal-annealing experiments. In this paper, we report on the microstructural changes of a Fe–15%Si alloy during in situ TEM annealing, where, in its bulk form, it exhibits an ordering transformation from D03 to B2 at 650 °C. Using a heating-pot type double tilt holder with a proportional–integral–differential control system, we observed the precipitation of α-Fe both at the sample surface and inside the sample. Surface precipitates formed via surface diffusion are markedly large, several tens of nm, whereas precipitates inside the specimen, which are surrounded by Fe-poor regions, reach a maximum size of 20 nm. This unexpected microstructural evolution could be attributed to vacancies on Si sites, which are induced due to high-energy electron irradiation before heating, as well as enhanced thermal diffusion of Fe atoms.
KW - In situ thermal-annealing experiment
KW - Microstructural changes of a Fe Si alloy
KW - Microstructural evolution
PY - 2022
DO - https://doi.org/10.1063/5.0070471
SN - 0021-8979
VL - 131
IS - 16
SP - 1
EP - 8
PB - AIP Publishing
AN - OPUS4-54728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Nishijima, M.
A1 - Kiguchi, T.
A1 - Konno, T.
T1 - Crystal structure characterization of martensite of Cu–Zn–Al ternary alloy by spherical aberration corrected scanning transmission electron microscopy
N2 - The crystal structure of martensite in Cu-27at.%Zn-9.0 at.%Al alloy has been studied by using sphericalaberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and geometrical phase analysis (GPA) to examine possible changes in atomic rearrangements during martensitic transformation of this ternary system. Observation along [100]M zone axis is suitable for examining a chemical order of the martensite, and showed that, despite the non-stoichiometry of the alloy, atomic columns containing
Al atoms are imaged and distinguished from the others. On the other hand, observation along [010]M zone axis directly revealed that the parent and martensitic phases possess L21 and 18R (21) structures, respectively. These observations suggested that the martensite retained the local chemical order of the parent phase without shuffling before and after the transformation. GPA revealed that the interface between the two phases was coherent with tilting of the basal plane approximately 6◦ across the boundary, which makes otherwise large inclination small during the martensitic transformation.
KW - Shape-memory alloys
KW - Martensitic transformation
KW - Martensitic structure
KW - Electron microscopy, transmission
PY - 2021
DO - https://doi.org/10.1016/j.intermet.2021.107286
SN - 0966-9795
VL - 137
PB - Elsevier Ltd.
AN - OPUS4-53076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maaß, Robert
T1 - The Federal Institute of Materials Research and Testing (BAM) – 150 Years of Enabling Scientific and Technological Breakthrough
N2 - BAM! This issue of Advanced Engineering Materials celebrates 150 years of scientific and technical research at the interface between academia, industry and politics. Rooted in 1871 at the birth of the German Empire and at that time located in simple basements and barracks, the institutional development began around mechanical metallurgy of iron and steel and represents today a diverse portfolio of fore-front research that orients itself along tomorrow's societal challenges and long-term research horizons.
KW - 150 Years
KW - Adolf Martens
PY - 2022
DO - https://doi.org/10.1002/adem.202200648
VL - 24
IS - 6
SP - 1
EP - 3
PB - Wiley-VCH GmbH
AN - OPUS4-55388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tehranchi, Ali
A1 - Zhang, S.
A1 - Zendegani, A.
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
A1 - Scheu, C.
T1 - Metastable defect phase diagrams as roadmap to tailor chemically driven defect formation
N2 - Thermodynamic bulk phase diagrams have become the roadmap used by researchers to identify alloy compositions and process conditions that result in novel materials with tailored properties. Recent experimental studies show that changes in the alloy composition can drive not only transitions in the bulk phases present in a material, but also in the concentration and type of defects they contain. Defect phase diagrams in combination with density functional theory provide a natural route to study these chemically driven defects.
Our results reveal, however, that direct application of equilibrium bulk thermodynamics can fail to reproduce experimentally observed defect formation. Therefore, we extend the concept to metastable defect phase diagrams to account for kinetic limitations that prevent the system from reaching equilibrium. We apply this concept to successfully explain the formation of large concentrations of planar defects in supersaturated Fe-Nb solid solutions. We then utilize it to design suitable conditions for synthesis, which we subsequently realized experimentally, successfully validating the formation of the predicted defects in Mg-Al-Ca alloys. The concept offers new avenues for the design of materials performance by tailoring defect structures.
KW - Metastable defect phase diagram
KW - Ab initio thermodynamics
KW - Chemical potential
KW - Laves phases
KW - Transmission electron microscopy
PY - 2024
DO - https://doi.org/10.1016/j.actamat.2024.120145
SN - 1359-6454
VL - 277
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-61803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Research data infrastructures as enablers for materials design
N2 - Suitable material solutions are of key importance in designing and producing components for engineering systems – either for functional or structural applications. Materials data are generated, transferred, and introduced at each step along the complete life cycle of a component. A reliable materials data space is therefore crucial in the digital transformation and an important prerequisite for machine learning in materials science.
Therefore, the consortium NFDI MatWerk aims to develop a sustainable infrastructure for the standardized digital representation of materials science and engineering (MatWerk). The goal is to seamlessly integrate decentralized data and metadata, experimental and computational workflows, and a materials ontology to maximize interoperability and reproducibility of materials data processing. To this end, data use profiles of participant projects from different sub-disciplines are analyzed to identify the most relevant scientific scenarios within MatWerk.
Similarly, the Plattform MaterialDigital (PMD) is committed to provide a prototypical infrastructure for the digitalization of materials in an industrial context implemented by decentralized data servers, semantic data schemas and digital workflows. The standards, methods, and tools developed within the PMD are deployed and consolidated within the context of currently more than 20 BMBF-funded academic and industrial research consortia. Scientific workflow environments represent a major focus area, including efforts to improve the definition and representation of digital workflows, as well as their distribution in form of a workflow store.
In this presentation we will describe the overarching visions behind these initiatives, their status, and progress of dissemination with a focus on the workflow activities and the connection between theoretical predictions and experimental solutions. Following the philosophy of both consortia, specific examples will be used to demonstrate innovative and pragmatic solutions.
T2 - FLAIR Colloquium
CY - Darmstadt, Germany
DA - 10.06.2024
KW - MaterialDigital
KW - NFDI-MatWerk
KW - Workflows
KW - Defect phase diagrams
PY - 2024
AN - OPUS4-62720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - On an experimentalist's hard search for free volume
N2 - This talk was given in honor of Prof. Frans Spaepen, faculty at Harvard University, at the occasion of his Staudinger Lecture and his honorary doctorate degree reception at ETH Zurich. It covers a 10 year long journey of how an experimentalist probes free-volume effects in metallic glasses.
T2 - Symposium in honor of Frans Spaepen Honorary Doctorate ETH Zurich
CY - Zurich, Switzerland
DA - 08.12.2023
KW - Metallic glass
KW - Deformation
KW - Shear bands
PY - 2023
AN - OPUS4-60717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Probing internal damage in glassy metals
N2 - This talk covers strain localization in metallic glasses and how it can be probed non-destructively using acoustic emission and x-ray methods. The results are compared to other methods and contextualized in the context of shear-band dynamics during inhomogeneous flow of metallic glasses.
T2 - Seminar Zerstörungsfreie Prüfung TU München 2023
CY - Online meeting
DA - 29.06.2023
KW - Metallic glass
KW - Deformation
KW - Acoustic emission
PY - 2023
AN - OPUS4-60718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Solute induced defect phase transformations in Mg alloys
N2 - The study of defect phases is important for designing nanostructured metals and alloys. Grain boundaries (GBs) form one class of defects that directly influence materials properties, such as deformability and strength. At the same time, alloying can introduce GB phase transformations and can therewith alter mechanical performance.
In this work, we will discuss the concept of GB phase diagrams for several examples. The focus will be on the defect phases of a Σ7 (12¯30) [0001] 21.78◦ symmetric tilt GB in hcp Mg. Ab-initio simulations as a function of stress and temperature (using quasi-harmonic approximation) are performed, and different types of phase transformations are revealed. To this end, the influence of the chemical degree of freedom on the defect phases is studied for the example of Ga addition, using an efficient screening approach that combines empirical potentials and accurate ab-initio calculations. By exploiting the concept of defect phase diagrams, a phase transformation from the T to the A structural type and as well as a systematic transition of the segregation site preference is revealed. The results qualitatively agree well with experimental observations from scanning transition electron microscopy. The underlying physical mechanisms have an impact on grain-boundary engineering in metallic alloys.
T2 - Calphad 2024 Conference
CY - Karlsruhe, Germany
DA - 26.05.2024
KW - Ab initio simulations
KW - Grain boundaries
KW - Defect phase diagram
KW - Segregation
PY - 2024
AN - OPUS4-62719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Temperature-dependent intermittent plasticity of Nb microcrystals
N2 - Intermittent microplasticity via dislocation avalanches indicates scale-invariance, which is a paradigm shift away from traditional bulk deformation. Recently, we have developed an experimental method to trace the spatiotemporal dynamics of correlated dislocation activity (dislocation avalanches) in microcrystals (Phys. Rev. Mat. 2 (2018) 120601; Phys. Rev. Mat. 3 (2019) 080601). Here we exploit the temperature sensitive deformation of bcc metals. A marked change of the slip-size distribution is observed in the studied microcrystals, with increasingly small event-sizes dominating with decreasing temperature. This shows how a reduction in thermal energy increasingly suppresses the length-scale of dislocation avalanches, indicating how long-range correlations become gradually limited to the scale of the lattice. Our results further show that the stress-strain response is composed of strain-increments that are either thermally activated or essentially athermal. Temperature-dependent small-scale testing in combination with state-of-the-art discrete dislocation dynamics (DDD) simulations of Nb microcrystals are used to reveal these insights.
T2 - MS&T20 Virtual
CY - Online meeting
DA - 02.11.2020
KW - Microcrystals
PY - 2020
AN - OPUS4-60700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Tracing structural dynamics in metallic glasses during cryogenic cycling
N2 - Highly unrelaxed structural states of metallic glasses have often advantageous mechanical properties. Since metallic glasses continuously relax with time (age) or inherently are well relaxed after processing, methods to uniformly rejuvenate the material are needed. One approach that has received attention is the so-called cryogenic-cycling method, during which a metallic glass is repeatedly immersed into liquid nitrogen. In some cases, cryogenic cycling is truly efficient in increasing the stored excess enthalpy of metallic glasses, but it does not seem to be universally applicable to all alloys and structural states. The origins for these differences remain unclear due to our limited understanding of the underlying structural evolution. In order to shed more light onto the fundamental structural processes of cryogenic cycling, we pursue in-situ x-ray photon correlation spectroscopy (XPCS) to trace the atomic-scale structural dynamics of a Zr-based metallic glass in two different structural states (ribbon and bulk metallic glass). This method allows calculating the relaxation times as a function of time throughout the thermal cycling. It is found that the investigated glasses exhibit heterogeneous structural dynamics at 300 K, which changes to monotonic aging at 78 K. Cryogenic cycling homogenizes the relaxation time distribution for both structural states. This effect is much more pronounced in the ribbon, which is the only structural state that rejuvenates upon cycling. We furthermore reveal how fast atomic-scale dynamics is correlated with long-time average structural relaxation times irrespective of the state, and that the ribbon exhibits unexpected additional fast atomic-scale relaxation in comparison to the plate material. Overall, a picture emerges that points towards heterogeneities in fictive temperature as a requirement for cryogenic energy storage.
T2 - MRS Fall 2020 - Invited Talk
CY - Boston, MA, USA
DA - 27.11.2020
KW - Relaxation metallic glasses
PY - 2020
AN - OPUS4-59542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Application of Density Functional Theory in the Context of Phase Diagram Modelling
N2 - An important pillar for the modelling of phase diagrams is the availability of accurate thermodynamic data for the individual phases. While experimental calorimetry is a powerful technique, a prediction of materials behavior solely on the computer, i.e. complementary to experimental investigations, has its own advantages. It allows one to resolve uncertainties in experimental data, to develop physical thermodynamic models and to determine free energies of phases that are not stable in reality. For this purpose, density functional theory (DFT), which does not require any experimental or empirical fit parameters, is the method of choice. Its advantage is to take the quantum-mechanical solution for the electronic wave functions as a starting point, when determining the chemical bonding of atoms. In the first part of the talk, I will speak about enthalpies of formation resulting from this approach, the underlying approximations, the achievable accuracies, as well as the typical incorporation into Calphad assessments.
We note, however, that a disadvantage of DFT is the restriction of the method to T = 0 K in their original formulation. Phase stabilities of real materials, on the other hand, are often dominated by processes that are due to finite temperatures. To include temperature effects in DFT, a significant method development was necessary in the last decade. In the second part of this talk, I will therefore provide the basic concepts for the calculation of vibrational, electronic, and magnetic entropy contributions. I will also highlight some recent methodological achievements in this field and show how these methods opened new routes in understanding and characterizing materials.
At the end a few examples of ab initio based phase diagrams will be discussed. The focus will be on phase stabilities and microstructure formation in Ni-based materials. The advantages of combining theoretical, experimental and Calphad concepts will be particularly emphasized.
T2 - MSIT Winter School on Materials Chemistry
CY - Tegernsee, Germany
DA - 21.01.2024
KW - Ab initio simulations
KW - CALPHAD
KW - Thermodynamics
KW - Free energies
PY - 2024
AN - OPUS4-62729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Constructing defect phase diagrams from ab initio calculations
N2 - Thermodynamic bulk phase diagrams have become the roadmap used by researchers to identify alloy compositions and process conditions that result in novel materials with tailored microstructures. On the other hand, recent progress in experimental atomic-scale characterization techniques allows one to study the local chemical composition at individual defects such as interfaces, grain boundaries, dislocations and surfaces. They show that changes in the alloy composition can drive not only transitions in the bulk phases present in a material, but also in the concentration and type of defects they contain. Defect phase diagrams, using chemical potentials as thermodynamics variables, provide a natural route to study these chemically driven defects. Our results show, however, that the direct application of thermodynamic approaches can fail to reproduce the experimentally observed defect formation.
Therefore, we extend the concept to metastable defect phase diagrams to account for kinetic limitations that prevent the system from reaching equilibrium. We use ab initio calculations based on density functional theory to quantify the extension of regions where defect formation is expected. We successfully applied this concept to explain the formation of large concentrations of planar defects in supersaturated Fe2Nb Laves phases. In addition, we identify in a joint study with experiments conditions and structures in Mg-Al-Ca alloys for defect phase occurrence. The concept offers new avenues for designing materials with tailored defect structures.
T2 - Materials Science Colloquium
CY - Uppsala, Sweden
DA - 25.04.2024
KW - Ab initio simulations
KW - Grain boundaries
KW - Defect phase diagram
KW - Laves phases
KW - Workflow
PY - 2024
AN - OPUS4-62731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Interoperable workflows combining software tools along the process chain of
materials
N2 - Material science problems have intrinsically multiscale and multiphysics characters, and require us to employ a combination of methods on different time and length scales to resolve critical features. Normally creating workflows that connect data in multiple scales and various methods is a cumbersome task. Pyiron, an integrated development environment (IDE) for material science, contains modules for the atomistic as well as continuum scale that make a seamless connection possible. To this end, it provides a high-level coherent language in a unified workflow platform to study materials, for example, with LAMMPS simulations in the same framework as crystal plasticity codes such as DAMASK. The latter is integrated such that all required input files can be generated, the analysis can be executed and the routines of the DAMASK post-processing library can be employed.
One example of a multi-scale workflow is the simulation of a multi-stage cold rolling process using pyiron. As with every DAMASK simulation, pre-processing includes the creation of the representative volume element and the material definition. It contains elastic properties that are obtained from LAMMPS calculations. To simulate the actual rolling process, the rolling subclass was implemented in the pyiron-job class. Since the total height decrease in technical rolling processes can be very large, the implementation provides for optional regridding between rolling passes. This is also required for the coupling with OpenPhase for simulating recrystallization using pyiron. To ensure interoperability between evaluation and simulation tools, work was done on a semantic representation of pyiron workflows.
T2 - MSE Conference 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Steel
KW - Workflows
KW - Multiscale simulation
KW - Ontology
PY - 2024
AN - OPUS4-62728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
A1 - Munsch, Sarah Mandy
T1 - Towards Sustainable Cement Compositions: Exploring the Effects of Clinker Substitutes with NMR and Induced Polarization
N2 - The reduction of clinker content in cement is a key strategy to lower the CO₂ footprint of the cement industry. In the recently approved composite cements of class CEM II, a significant portion of the clinker (up to 50%) can already be replaced. A promising option in this context is the so-called LC³ (Limestone Calcined Clay Cement), which offers exciting alternatives especially for countries with large clay deposits. To ensure the performance and durability of such binders, understanding hydration processes and the role of the used supplementary cementitious materials (SCMs) is crucial.
The authors present findings from two independent studies: a master thesis and a round-robin experiment conducted within a RILEM Technical Committee. Both studies investigate cementitious materials incorporating SCMs using advanced characterization techniques. The master thesis focuses on early hydration processes during the first 100 hours using Nuclear Magnetic Resonance relaxometry (NMR), providing detailed insights into microstructural development, hydrogen bonding, and water mobility. In contrast, the round-robin experiment explores hydration and durability over a longer timeframe of 3 to 91 days using induced polarization (IP) to study bulk conductivity and its changes with age. For all investigated mixtures—including pure Ordinary Portland (CEMI), Portland Limestone Cement (CEM II) including blends with calcined clay and fly ash—heat flow calorimetry serves as a reference method to monitor hydration progress during the early stages.
This approach allows a comprehensive understanding of the effects of SCMs on hydration, combining short-term and long-term perspectives while leveraging complementary techniques. Preliminary results demonstrate a significant increase in NMR T₂ relaxation times with the addition of fly ash, accompanied by a strong reduction in the free water component. Concurrently, early IP measurements reveal a steady increase in impedance with sample age, particularly pronounced in mixtures containing calcined clay. These findings underline the potential of NMR and IP to evaluate hydration and durability-related properties in cementitious systems with reduced clinker content.
T2 - 85. Jahrestagung der Deutschen Geophysikalischen Gesellschaft
CY - Bochum, Germany
DA - 24.02.2025
KW - Nuclear magnetic resonance
KW - Induced polarization
KW - Supplementary cementitious materials
PY - 2025
AN - OPUS4-62989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Wallis, Theophilus
T1 - Density-Based Phase-Field Modeling of Grain Boundary Segregation and Structural Transitions
N2 - Polycrystalline materials are central to everyday engineering applications and technological advancements. The mechanical and functional properties of these materials can be influenced either negatively or positively by the presence of grain boundaries (GBs). These properties are interconnected with the structure, chemistry, or a combination of both (referred to as chemo-structure) at the GB.
Therefore, an in-depth understanding of GBs, and their associated phenomena is key to tuning these materials properties for desired applications. Nevertheless, the intricate and unique characteristics of GBs impose constraints on their general descriptions in existing models designed for studying and understanding them. In this dissertation, a comprehensive tool, the CALPHAD-integrated density-based phase-field (DPF) model \cite{darvishikamachali2020model}, that harnesses atomic-scale GB characteristics, is employed and extended to reveal a deeper understanding of the GB structure, chemistry, chemo-structural coupling and their potential contributions to GB phenomena such as GB structural (and/or chemo-structural) transitions and liquid metal embrittlement.
Although GBs possess distinctive crystallographic properties that render them unique and individualistic, it is important to note that they cannot exist independently; rather, they are made of the same constituents as the corresponding bulk material.
To this end, the DPF model uses a continuous atomic density field ($\rho$), derived from atomistic simulations, to characterize the GB with reference to its corresponding homogeneous bulk (grain interior).
This perspective allows the DPF model to approximate the GB free energy functional based on available bulk thermodynamic data.
The DPF model has been utilized to investigate a variety of systems, form unary to multi-component systems \cite{kamachali2024giant,darvishikamachali2020model,darvishikamachali2020segregation,wang2021density,li2020grain,wang2021incorporating,zhou2021spinodal}.
Among several novelties in the elucidation of the thermodynamics and kinetics of GBs, the DPF model has shown that GBs can have their own miscibility gap.
It further reveals a temporal co-evolution of low and high segregation levels at the GB, which can act as precursor states for the formation of new phases \cite{kwiatkowskidasilva2018phase, kwiatkowskidasilva2019thermodynamics}.
In the recent publication on Fe-Mn \cite{darvishikamachali2020segregation} and in various other works \cite{kamachali2024giant,darvishikamachali2020model,darvishikamachali2020segregation,wang2021density,li2020grain,wang2021incorporating,zhou2021spinodal, ikeda2023segregation, ahmadian2023interstitial} of the DPF model, the variation of atomic density field was allowed normal to the GB plane.
At the GB plane, the in-plane GB density $\rho^{GB}$ was treated as a constant average value, representing its intrinsic dependence on the GB nature and misorientation.
Although this assumption provides a useful simplification in studying GB phenomena, it does have the drawback of overlooking the significance of the in-plane structure variation.
This seems to be particularly central in the view of experimental observations that confirm relatively stable grain boundary composition fluctuation \cite{darvishikamachali2020segregation}.
In this thesis, the significance and impact of the atomic structure of GBs on their thermodynamics is investigated. This is achieved in two ways: On one hand, by extending the CALPHAD-integrated density-based free energy functional to account for structural degrees of freedom of GBs, and on the other hand, by deducing and linking density-related GB properties to the GB structure through the results of atomistic simulation of the GBs.
Naturally, the structure (atomic density) within the GB plane fluctuates.
This variation may also be linked to changes in composition due to solute segregation at the GB.
While the fact that the GB structure can undergo transitions (referred to as complexions) \cite{frolov2015segregation, cantwell2020grain, cantwell2014grain} is not entirely new, the quantitative measurements of co-existing GB phases are scarce.
Recently, instances were reported where the coexistence of two in-plane GB phases was revealed through the application of high-resolution transmission electron microscopy and atomistic simulation \cite{frommeyer2022dual, meiners2020observations}.
To this end, the potential of GB structural variation within the DPF model is introduced in this thesis, where the GB in-plane density $\rho^{GB}$ is described as a field, that can vary both in time and space.
This extension enables the in-plane GB density $\rho^{GB}$ to evolve and exhibit two distinct low-energy states, denoted as $\rho^{GB} = \rho_1$ and $\rho^{GB} = \rho_2$, where $\rho_2 > \rho_1$.
Separating these two structural states is an in-plane line defect.
This way, the model allows the studies of the co-evolution between the chemical and structural states of the GB.
As a proof of concept and benchmark study, the extended-DPF model is implemented for studying Fe-Mn system.
The results show that the GB structure's capacity to respond to chemical variations, as incorporated in the DPF model, enhances the Mn segregation transition at the GB, even in the absence of any alterations to the GB structure.
When the GB structure undergo changes (or is non-uniform), the model reveals a coupling between the GB structure and chemical evolution.
The ability of the GB structure to change allows the coexistence of spinodally formed low- and high-Mn phases within the GB during segregation transition.
The acquired equilibrium segregation isotherms provides insight into the range of alloy compositions where these GB phases remain stabilised.
Moreover, the observations indicate that the tendency of the GB to undergo a structural transition (change) is associated with the energy of the in-plane line defect, between low- and high-density domains within the GB plane.
The extended-DPF model is further applied to Zn-coated advanced high strength steels (Fe-Zn systems), where Zn segregation to the GB is known to cause severe performance degradation due to liquid metal embrittlement \cite{razmpoosh2021pathway, ikeda2022early, bhattacharya2018liquid}.
The effect of GB type and its chemo-structural coupling on Zn segregation is investigated. The results showed a sharp Zn segregation that is strongly influenced by the nature of the GB itself, as well as the coupling between its chemistry and structure.
Additionally, GB phase diagrams were constructed across a wide range of alloy compositions and temperatures.
The impact of the GB type and chemo-structural coupling on the miscibility gap of GBs is discussed.
The DPF model's ability to incorporate atomic-scale characteristics into the construction of Gibbs free energies at the mesoscale ensures it retains key physical insights when predicting microstructure properties.
To this end, a robust investigation of the model’s parameters and outputs in comparison to atomistic simulations of GBs is presented.
This not only serves as a gauge for the models reliability, but also provide a new framework in establishing an atomistically-informed density-based description of GBs.
First, by examining a large dataset of GBs in BCC-Fe and -Mo from atomistic simulations, a connection between their discrete atomic structure and the continuous atomic density function $\rho$ is established.
This is achieved by a systematic coarse-graining approach wherein an atomsitically-obtained density function (delta function) is substituted with a normalised Gaussian function, so that, a
smooth and continuous atomic density profile in real space can be obtained, where the minimum is the average atomic density at the GB plane $\rho^{GB}$.
The investigation revealed a linear proportional relationship between the GB excess free volume and $\rho^{GB}$.
This correlation simplifies the computation of the excess free volume as the integration over the portion of the density profile where the atomic density is less than one.
Furthermore, the GB energies calculated by atomistic simulations revealed a correlation with $\rho^{GB}$ for certain classification of GB types, therefore enhancing the model's predictive accuracy.
Concurrently, the atomic-scale characteristics of GBs can be further harnessed in the DPF models by replacing the simple functional form of the potential energy as given in the original DPF model formulation with a material specific interatomic potential (expressed as a function of the atomic density $\rho$) from molecular dynamic simulations.
This way, a reliable prediction of the atomic density gradient energy coefficient for mesoscale simulations can be obtained.
KW - Grain boundary structure
KW - Grain boundary chemistry
KW - Density-based phase-field modelling
KW - Grain boundary thermodynamics
KW - Grain boundary segregation transition
PY - 2025
SP - 1
EP - 134
CY - Aachen
AN - OPUS4-64455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Syed, F. W.
A1 - Saikia, Ujjal
A1 - Sun, B.
A1 - Kiranbabu, S.
A1 - Tehranchi, Ali
A1 - Hickel, Tilmann
A1 - Zaefferer, S.
A1 - Ponge, D.
T1 - Interfacial segregation of carbon atoms: the competition between grain boundaries and phase boundaries
N2 - The microstructure of a two-phase medium manganese steel is decorated by interfaces whose character is defined by crystallography and the misorientation between adjacent grains, which in turn influences elemental segregation and shapes the resulting decorations. This study investigates how adjacent grain and phase boundaries impact a boundary’s segregation behavior, with a focus on the competition for carbon (C) enrichment in a laminated ferrite (α)- austenite (γ) microstructure subjected to a series of heat treatments. It was found that semicoherent α-γ Kurdjumov-Sachs (KS) phase boundaries show less carbon segregation than general γ grain boundaries. Furthermore, when a γ grain boundary is present at a junction with the phase boundaries, it acts as an extracting agent for C. DFT calculations support these observations, demonstrating that carbon segregation is energetically more favorable at the γ grain boundary compared to the α/γ phase boundary, due to the more negative segregation energy at the former.
KW - Defects
PY - 2025
DO - https://doi.org/10.1016/j.scriptamat.2025.116842
SN - 1359-6462
VL - 268
SP - 1
EP - 6
PB - Elsevier Inc.
AN - OPUS4-63840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fotheringham, U.
T1 - Digitalization of Glass Development
N2 - Im Vortrag werden erste Ergebnisse aus dem vom BMFTR im Rahmen der MaterialDigital Initiative geförderten Projekt „GlasAgent“ vorgestellt, welches die Glasentwicklung mittels KI vorantreiben soll. In diesem Projekt werden mehrere Entwicklungszyklen inklusive des Recyclingprozesses durchlaufen und die Ergebnisse genutzt, um Datenbanken und Modelle zu verbessern. Mit diesen verknüpft und basierend auf der semantischen GlasDigital-Ontologie soll zukünftig ein Chatbot die Glasentwicklung schneller, präziser und nachhaltiger gestalten.
T2 - PMD Vollversammlung
CY - Berlin, Germany
DA - 26.11.2025
KW - Glass
KW - Workflow
KW - Automation
KW - MAP
KW - Ontology
KW - Simulation
KW - Database
PY - 2025
AN - OPUS4-65039
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Platform MaterialDigital (PMD) - Knowledge Representation, Interoperability, Reliability
N2 - Through collaboration in the materials science and engineering (MSE) community, the PMD is collectively developing common standards and prototype solutions for data acquisition, structuring, storage, and processing. This comprises the development of architectural, standardized and foundational ontologies and workflows. Demonstrators resulting from these developments provide good practice examples. The PMD Core Ontology (PMDco) was created as an anchor that allows implementation of semantic data integration. It provides a common and expanding vocabulary to represent and share knowledge while enabling efficient collaboration and promoting interoperability between diverse domains.
T2 - Kupfer-Symposium 2025
CY - Schwäbisch-Gmünd, Germany
DA - 12.11.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
KW - PMD Core Ontology
PY - 2025
AN - OPUS4-64708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yao, Xingyu
A1 - Antunes, Margarida M.
A1 - Guilherme Buzanich, Ana
A1 - Cabanelas, Pedro
A1 - Valente, Anabela A.
A1 - Pinna, Nicola
A1 - Russo, Patrícia A.
T1 - Formation, Phase Transition, Surface, and Catalytic Properties of Cubic ZrO 2 Nanocrystals
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-Performance sodium storage anode. The presence of iron triggers the loss of long-rangeorder through disorder of the FeO6 octahedra local structure, subsequentlyallowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites forpseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - XAS
KW - Sodium-ion Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654955
DO - https://doi.org/10.1021/acs.chemmater.5c01483
SN - 0897-4756
VL - 37
IS - 21
SP - 8568
EP - 8580
PB - American Chemical Society (ACS)
AN - OPUS4-65495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Faustino, Leandro A.
A1 - de Angelis, Leonardo D.
A1 - de Melo, Eduardo C.
A1 - Farias, Giliandro
A1 - dos Santos, Egon C.
A1 - Miranda, Caetano R.
A1 - Buzanich, Ana G.
A1 - Torresi, Roberto M.
A1 - de Oliveira, Paulo F.M.
A1 - Córdoba de Torresi, Susana I.
T1 - Urea synthesis by Plasmon-Assisted N2 and CO2 co-electrolysis onto heterojunctions decorated with silver nanoparticles
N2 - The N2 + CO2 co-electrolysis to urea synthesis has become a promising alternative to the energy intensive traditional processes for urea production. However, there are still challenges in this approach, especially due to the competition with HER (Hydrogen Evolution Reaction) leading to low efficiency. Electrochemistry assisted by localized surface plasmon resonance (LSPR) using metal nanoparticles has been reported to enhance different electrochemical reactions. Here we report an electrochemical LSPR assisted urea synthesis using Ag nanoparticles (NPs) supported on BiVO4/BiFeO3 catalyst mechanochemically synthesized. The electrochemical experiments were performed under dark and upon plasmon excitation at the LSPR region of Ag NPs. Our results demonstrated that exciting in the LSPR range, urea yield rate and Faradic efficiency were considerably improved with reduced overpotential, 19.2 μmol h− 1 g− 1 and FE 24.4% at +0.1 V vs RHE compared to 9.6 μmol h− 1 g− 1 and FE 9.4% at − 0.2 V vs RHE under dark conditions. Further in situ FTIR-RAS experiments for mechanism investigation revealed the presence of N-H and C-N intermediates and the real effect of Ag plasmon excitation on HER and N2 + CO2 co-electrolysis. Theoretical calculations confirm the energy of the species involved in C-N coupling as well the role of the complex catalytic sites, which agrees with XAS measurements.
KW - Plasmon-assited
KW - XAS
KW - Urea
KW - Electrocatalysis
PY - 2025
DO - https://doi.org/10.1016/j.cej.2025.163072
SN - 1385-8947
VL - 513
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallis, Theophilus
A1 - Ratanaphan, Sutatch
A1 - Darvishi Kamachali, Reza
T1 - Linking atomistic and phase-field modeling of grain boundaries I: Coarse-graining atomistic structures
N2 - The longstanding gap between atomistic and mesoscale simulations partly lies in the absence of a direct, physically grounded connection between atomic structure and mesoscale fields. In this work, we present a robust coarse-graining approach to systematically investigate the connection between phase-field and atomistic simulations of grain boundaries (GBs). The atomistic structures of 408 GBs in BCC-Fe and -Mo were studies to compute and analyze a continuous atomic density field. We discover a fundamental relationship between the GB density---defined as the average atomic density at the GB plane---and the GB excess free volume, an integral property of the boundary. An almost perfect linear correlation between the GB atomic density and GB excess free volume is identified. We also show that the width of BCC GBs, when scaled by the lattice constant, approaches a universal constant value. The relationships among GB density, width, and energy are systematically examined for various GB planes, and the GB energy--density correlations are classified with respect to GB types. It turns out that the atomic planes forming the GB strongly influence both the GB density and excess volume. The current results establish a dependable framework to bridge across scales, enabling density-based phase-field modeling of GBs with atomistic fidelity and enhancing the predictive reliability of mesoscale simulations.
KW - Density-based model
KW - Grain boundary structure
KW - Grain boundary thermodynamic
KW - Atomistic simulations
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654872
DO - https://doi.org/10.1016/j.actamat.2025.121786
SN - 1359-6454
VL - 305
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-65487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallis, Theophilus
A1 - Darvishi Kamachali, Reza
T1 - Linking atomistic and phase-field modeling of grain boundaries II: Incorporating atomistic potentials into free energy functional
N2 - The density-based phase-field model for grain boundary (GB) thermodynamics and kinetics has offered a broad range of applications in alloy and microstructure design. Originally, this model is based on a potential energy terms that is connected to the cohesive energy of a given substance. A more rigorous approach, however, is a full consideration of an interatomic potential over the possible range of distance and therefore density. In Manuscript I of this series, we developed and thoroughly analyzed the coarse-graining of atomistic GB structures. In this work (Manuscript II), we complete the coupling between atomic and mesoscale modeling of GBs by incorporating the full interatomic potentials into the density-based free energy functional. Using GB energies calculated from atomistic simulations, the coarse-graining approach and the atomistic-integrated density-based Gibbs free energy, we effectively evaluate the density gradient energy coefficient. We found that coupling the density-based model with atomistic potentials reveal physically-sound trends in the GB equilibrium properties. A universal equation was derived to describe the potential energy contribution to the GB energy and the gradient energy coefficient for BCC-Fe and -Mo GBs, similar to the universal equation for GB excess free volume presented in Manuscript I. The proposed approach provides a mesoscale density-based model rooted in atomic-scale characteristics for reliable predictions of GB properties.
KW - Density-based model
KW - Phase-field
KW - Grain boundary structure
KW - Grain boundary thermodynamics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654904
DO - https://doi.org/10.1016/j.actamat.2025.121787
SN - 1359-6454
VL - 305
SP - 1
EP - 17
PB - Elsevier
AN - OPUS4-65490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yanchen
A1 - Guilherme Buzanich, Ana
A1 - Alippi, Paola
A1 - Montoro, Luciano A.
A1 - Lee, Kug‐Seung
A1 - Jeon, Taeyeol
A1 - Weißer, Kilian
A1 - Karlsen, Martin A.
A1 - Russo, Patrícia A.
A1 - Pinna, Nicola
T1 - FeNb 2 O 6 as a High‐Performance Anode for Sodium‐Ion Batteries Enabled by Structural Amorphization Coupled with NbO 6 Local Ordering
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-performance sodium storage anode. The presence of iron triggers the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - SIB
KW - XAS
KW - Sodium-ion Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654931
DO - https://doi.org/10.1002/adma.202504100
SN - 0935-9648
VL - 37
IS - 46
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-65493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bustos, Jenna
A1 - Shohel, Mohammad
A1 - Guilherme Buzanich, Ana
A1 - Zakharov, Lev
A1 - Buils, Jordi
A1 - Segado‐Centellas, Mireia
A1 - Bo, Carles
A1 - Nyman, May
T1 - Technetium and Rhenium Auto‐reduction, Polymerization and Lability towards Group VII Polyoxometalate Chemistry
N2 - AbstractGroup VII Tc and Re have long been studied to develop both radiopharmaceuticals and technologies for nuclear materials management. Fundamental research has targeted understanding this periodic table crossroads where polyoxometalates meets metal‐metal bonded complexes. Here we have isolated green hygroscopic and metastable crystals of (ReVI,oct)2(ReVII,tet)2(OH)2(O)12⋅H2O (ReVI,VII‐green, tet=tetrahedral, oct=octahedral), determined by single‐crystal x‐ray diffraction. In addition to color, Re‐L1 X‐ray absorption near‐edge spectroscopy confirms the reduced oxidation state. ReVI,VII‐green provides the first demonstration of Re autoreduction, long‐observed for Mn and Tc. We also isolated and structurally characterized [Tc4O4(H2O)2(ReO4)14]2− (Tc4Re14) polyanion crystals that contain Tc(V) and Re(VII), consistent with greater stability of reduced Tc compared to reduced Re. Small angle X‐ray scattering of both compounds and prior‐reported polyanion [Tc4O4(H2O)2(TcO4)14]4− (Tc20) dissolved in acetonitrile indicated a qualitative lability order of oxo‐linkages of Re‐O−Re Re‐O−Tc Tc‐O−Tc, and lability of Tc20 was also probed by 99Tc nuclear magnetic resonance spectroscopy. Computation provided insight into 99Tc chemical shifts as well as lability. Based on both reducibility and solution phase dynamics of polynuclear compounds investigated here, Re is an imperfect surrogate for Tc, and further expansion of group VII polyoxometalate chemistry seems promising.
KW - XANES
KW - Polyoxometalate
KW - Technetium
PY - 2025
DO - https://doi.org/10.1002/chem.202404144
SN - 0947-6539
VL - 31
IS - 21
SP - 1
EP - 7
PB - Wiley-VCH Verl.
AN - OPUS4-65491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, A.
A1 - Dufresne, E.M.
A1 - Maaß, Robert
T1 - Structural dynamics and rejuvenation during cryogenic cycling in a Zr-based metallic glass
N2 - Subjecting metallic glasses repeatedly to liquid nitrogen temperature has become a popular method to homogeneously rejuvenate the material. Here we reveal the atomic-scale structural dynamics using in- situ x-ray photon correlation spectroscopy (XPCS) during and after cryogenic cycling of a Zr-based metallic glass in two structural states (plate and ribbon). Heterogeneous structural dynamics is observed at 300 K that changes to monotonic aging at 78 K. It is found that cryogenic cycling homogenizes the relaxation time distribution. This effect is much more pronounced in the ribbon, which is the only structural state that rejuvenates upon cycling. We furthermore reveal how fast atomic-scale dynamics is correlated with longtime structural relaxation times irrespective of the structural state, and that the ribbon exhibits unexpected additional fast atomic-scale relaxation in comparison to the plate material. A structural picture emerges that points towards heterogeneities in the fictive temperature as a requirement for cryogenic energy storage.
KW - Structural dynamics
KW - Metallic glass
KW - Relaxation
KW - Rejuvenation
KW - Cryogenic cycling
PY - 2020
DO - https://doi.org/10.1016/j.actamat.2020.06.063
SN - 1359-6454
VL - 196
SP - 723
EP - 732
PB - Elsevier Ltd.
AN - OPUS4-51311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abboud, M.
A1 - Motallebzadeh, A.
A1 - Duygulu, O.
A1 - Maaß, Robert
A1 - Özerinc, S.
T1 - Microstructure and nanomechanical behavior of sputtered CuNb thin films
N2 - We report on the mechanical properties of Cu–Nb alloys produced by combinatorial magnetron sputtering.
Depending on the composition, the microstructure is either fully amorphous (~30–65 at.% Cu), a dispersion of Cu crystallites in an amorphous matrix (~70 at.%), or a dominant crystalline phase with separated nanoscale amorphous zones (~80 at.% Cu). Nanomechanical probing of the different microstructures reveals that the hardness of the fully amorphous alloy is much higher than a rule of mixture would predict. We further demonstrate a remarkable tunability of the resistance to plastic flow, ranging from ca. 9 GPa in the amorphous regime to ca. 2 GPa in the fully crystalline regime. We rationalize these findings based on fundamental structural considerations, thereby highlighting the vast structure-property design space that this otherwise immiscible binary alloy provides.
KW - Deposition microstructure
KW - Metallic glasses
KW - Thin films
KW - Mechanical properties
KW - Nanocrystalline structure
PY - 2021
DO - https://doi.org/10.1016/j.intermet.2021.107249
SN - 0966-9795
VL - 136
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-52777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rizzardi, Q.
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - Microstructural signatures of dislocation avalanches in a high-entropy alloy
N2 - Here, we trace in situ the slip-line formation and morphological signature of dislocation avalanches in a highentropy alloy with the aim of revealing their microstructural degree of localization. Correlating the intermittent microplastic events with their corresponding slip-line patterns allows defining two main event types, one of which is linked to the formation of new slip lines, whereas the other one involves reactivation of already existing slip lines. The formation of new slip lines reveals statistically larger and faster avalanches. The opposite tendency is seen for avalanches involving reactivation of already existing slip lines. The combination of both these types of events represents the highest degree of spatial avalanche delocalization that spans the entire sample, forming a group of events that determine the truncation length scale of the truncated power-law scaling. These observations link the statistics of dislocation avalanches to a microstructural observable.
KW - High-entropy alloy
KW - Dislocation avalanches
PY - 2021
DO - https://doi.org/10.1103/PhysRevMaterials.5.043604
SN - 2475-9953
VL - 5
IS - 4
SP - 3604
PB - American Physical Society
CY - College Park, MD
AN - OPUS4-52458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Honrao, S. J.
A1 - Rizzardi, Q.
A1 - Maaß, Robert
A1 - Trinkle, D. R.
A1 - Hennig, R. G.
T1 - Split-vacancy defect complexes of oxygen in hcp and fcc cobalt
N2 - One of the most ubiquitous and important defects in solids is oxygen. Knowledge about the solubility and diffusivity of oxygen in materials is crucial to understand a number of important technological processes, such as oxidation, corrosion, and heterogeneous catalysis. Density-functional theory calculations of the thermodynamics and kinetics of oxygen in cobalt show that oxygen diffusing into the two close-packed phases, namely α (hcp) and β (fcc), strongly interacts with vacancies.We observe the formation of oxygen split-vacancy centers (V-Oi-V) in both phases, and we show that this defect complex exhibits a similar migration energy barrier to the vacancy and oxygen interstitials. In contrast to the vacancy and oxygen interstitials, the oxygen split-vacancy centers exhibit an anisotropic strain field that couples to applied stress, making it possible to observe them through an internal friction experiment on quenched cobalt.
KW - Split-vacancy defect complexes
PY - 2020
DO - https://doi.org/10.1103/PhysRevMaterials.4.103608
VL - 4
IS - 10
SP - 103608-1
EP - 103608-9
PB - American Physical Society
AN - OPUS4-51582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Mancias, J.
A1 - Gan, B.
A1 - Maaß, Robert
T1 - Evidence of room-temperature shear-deformation in a Cu-Al intermetallic
N2 - Lamellar eutectics are known to evidence plastic shear in otherwise brittle intermetallics, if the lamella spacing is small enough. Here we pursue this idea of confined plasticity in intermetallics further and demonstrate room-temperature shear-deformation in a two-phase CuAl 2 -CuAl intermetallic nano- composite. The presence of a phase with a 3-fold symmetry is also revealed after deformation. Simula- tion of transmission electron microscopy images shows this to be monoclinic CuAl. These observations are made in the deformation zone underneath locations of nanoindents, of which the force-displacement curves exhibit an unusual response of continuously increasing pop-in sizes with load.
KW - Nanoindentation
KW - Intermetallic
KW - Nano-composite
KW - Shear bands
KW - Plasticity
PY - 2021
DO - https://doi.org/10.1016/j.scriptamat.2020.08.033
VL - 190
SP - 126
EP - 130
PB - Elsevier Ltd.
AN - OPUS4-52455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shanmugam, Sankaran
A1 - Peterlechner, Martin
A1 - Iskandar, Mohamad Riza
A1 - Saikia, Ujjal
A1 - Kulitckii, Vladislav
A1 - Lipińska-Chwałek, Marta
A1 - Mayer, Joachim
A1 - Rösner, Harald
A1 - Hickel, Tilmann
A1 - Divinski, Sergiy V.
A1 - Wilde, Gerhard
T1 - Coherent twin-oriented Al3Sc-based precipitates in Al matrix
N2 - Al3(Sc,Zr,Ti) nanoparticles with an ideal twin-type orientation relationship to Al host matrix were found in cold-rolled and subsequently annealed Al-based alloy. Atomic-scale investigations using high-resolution scanning transmission electron microscopy identified particles that form prominent coherent (111) twin-type interfaces along their longer facets and semi-coherent twin interfaces on their shorter facets. Ab-initio calculations showed that a coherent Al/Al3Sc twin-like phase boundary corresponds to a local energy minimum. A model is proposed explaining the formation of the twin orientation relationship of an Al3Sc nanoparticle with the Al host matrix.
KW - Al-based alloy
KW - Precipitation
KW - Twin orientation relationship
KW - Ab initio calculations
KW - Transition electron microscopy
PY - 2023
DO - https://doi.org/10.1016/j.scriptamat.2023.115351
SN - 1359-6462
VL - 229
SP - 1
EP - 6
PB - Elsevier BV
AN - OPUS4-58789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Design of finite temperature materials properties enabled by digital concepts
N2 - Since the function of materials is controlled by properties and processes on the atomic scale, ab initio based high-throughput methods are valuable strategies in materials design. For computational efficiency, they are however often restriction to T=0K calculations, while many technologically relevant materials properties and thermodynamic stabilities change when going from low to high temperatures. On the other hand, the constantly increasing performance of digital tools for simulation and data-driven science enables more targeted material development including these kinds of finite-temperature effects. A flexible infrastructure, including data management and workflow solutions is required to make this symbiosis user-friendly efficient. Within this presentation, examples from ab initio thermodynamics for the design of phase stabilities in hard-magnetic alloys and defect-phases in advanced high-strength steels will be demonstrated. We will discuss physical concepts with a focus at the impact of magnetic excitations. At the same time, the examples will be used to derive requirements and present solutions for a digital infrastructure. An outlook will be given to current strategies with the NDFI initiative NFDI-MatWerk.
T2 - FEMS Euromat Conference 2023
CY - Frankfurt/Main, Germany
DA - 03.09.2023
KW - Ab initio simulations
KW - Workflows
KW - Chemically complex alloys
KW - Hard magnetic materials
KW - Thermodynamics
PY - 2023
AN - OPUS4-58848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Constructing defect phase diagrams from ab initio calculations
N2 - Thermodynamic bulk phase diagrams have become the roadmap used by researchers to identify alloy compositions and process conditions that result in novel materials with tailored microstructures. On the other hand, recent progress in experimental atomic-scale characterization techniques allows one to study the local chemical composition at individual defects such as interfaces, grain boundaries, dislocations and surfaces. They show that changes in the alloy composition can drive not only transitions in the bulk phases present in a material, but also in the concentration and type of defects they contain. Defect phase diagrams, using chemical potentials as thermodynamics variables, provide a natural route to study these chemically driven defects. Our results show, however, that the direct application of thermodynamic approaches can fail to reproduce the experimentally observed defect formation.
Therefore, we extend the concept to metastable defect phase diagrams to account for kinetic limitations that prevent the system from reaching equilibrium. We use ab initio calculations based on density functional theory to quantify the extension of regions where defect formation is expected. We successfully applied this concept to explain the formation of large concentrations of planar defects in supersaturated Fe2Nb Laves phases. In addition, we identify in a joint study with experiments conditions and structures in Mg-Al-Ca alloys for defect phase occurrence. The concept offers new avenues for designing materials with tailored defect structures.
T2 - Birmingham University, Seminar in physical chemistry
CY - Birmingham, UK
DA - 21.07.2023
KW - Atomistic models
KW - Phase transitions
KW - Defects
PY - 2023
AN - OPUS4-58843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Constructing defect phase diagrams from ab initio calculations
N2 - Thermodynamic bulk phase diagrams have become the roadmap used by researchers to identify alloy compositions and process conditions that result in novel materials with tailored microstructures. Recent experimental studies show that changes in the alloy composition can drive not only transitions in the bulk phases present in a material, but also in the concentration and type of defects they contain. Defect phase diagrams in combination with density functional theory provide a natural route to study these chemically driven defects. Our results show, however, that direct application of thermodynamic approaches can fail to reproduce the experimentally observed defect formation. Therefore, we extend the concept to metastable defect phase diagrams to account for kinetic limitations that prevent the system from reaching equilibrium. We successfully applied this concept to explain the formation of large concentrations of planar defects in supersaturated Fe-Nb solid solutions and to identify in a joint study with experiments conditions in Mg-Al-Ca alloys for defect phase occurrence. The concept offers new avenues for designing materials with tailored defect structures.
T2 - Fritz-Haber-Institut Seminar
CY - Berlin, Germany
DA - 23.03.2023
KW - Ab initio simulations
KW - Defects
KW - Phase diagrams
PY - 2023
AN - OPUS4-58849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - The Platform MaterialDigital (PMD) and the goal of a Materials Data Space
N2 - Suitable material solutions are of key importance in designing and producing components for engineering systems – either for functional or structural applications. Materials data are generated, transferred, and introduced at each step along the complete life cycle of a component. A reliable materials data space is therefore crucial in the digital transformation of an industrial branch.
Therefore, the “Innovation Platform MaterialDigital (PMD) funded by the German Federal Ministry of Education and Research (BMBF), aims to develop a sustainable infrastructure for the standardized digital representation of materials science and materials engineering. With its partners (KIT, Fraunhofer IWM, FIZ, Leibnitz IWT, BAM, MPIE), the PMD is committed to build up a materials science data space. To achieve this the PMD provides a prototypical infrastructure for the digitalization of materials implemented by decentralized data servers, standardized data schemas and digital workflows. Following the FAIR principles, it will promote the semantic interoperability across the frontiers of materials classes.
Standards, methods, and tools developed within the platform are deployed and consolidated within the context of currently near 20 BMBF-funded academic and industrial research consortia and made available to the material science community in general. In this context scientific workflows represent a major focus area, represented within the platform by the workflow frameworks pyiron and SimStack. In consequence, the platform is building up a digital library in form of a workflow store along with common standards for the definition and representation of digital workflows.
In this presentation we will describe the status of our Platform MaterialDigital with a focus on the workflow activities. The current status and the vision for dissemination of the solutions developed in the PMD within the community are provided.
T2 - 4th EMMC International Workshop 2023
CY - Vienna, Austria
DA - 26.04.2023
KW - Platform MaterialDigital
KW - Workflows
KW - Data Management
PY - 2023
AN - OPUS4-58846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Ab initio Thermodynamics of defect phases in metals
N2 - Thermodynamic bulk phase diagrams have become the roadmap used by researchers to identify alloy compositions and process conditions that result in novel materials with tailored microstructures. On the other hand, recent progress in experimental atomic-scale characterization techniques allows one to study the local chemical composition at individual defects such as interfaces, grain boundaries, dislocations and surfaces. They show that changes in the alloy composition can drive not only transitions in the bulk phases present in a material, but also in the concentration and type of defects they contain. Defect phase diagrams, using chemical potentials as thermodynamics variables, provide a natural route to study these chemically driven defects. Our results show, however, that the direct application of thermodynamic approaches can fail to reproduce the experimentally observed defect formation.
Therefore, we extend the concept to metastable defect phase diagrams to account for kinetic limitations that prevent the system from reaching equilibrium. We use ab initio calculations based on density functional theory to quantify the extension of regions where defect formation is expected. We successfully applied this concept to explain the formation of large concentrations of planar defects in supersaturated Fe2Nb Laves phases. In addition, we identify in a joint study with experiments conditions and structures in Mg-Al-Ca alloys for defect phase occurrence. The concept offers new avenues for designing materials with tailored defect structures.
T2 - 19th Int. Conference on Diffusion in Liquids and Solids
CY - Heraklion, Greece
DA - 26.06.2023
KW - Density functional theory
KW - Defects
KW - Phase diagrams
KW - Mg alloys
PY - 2023
AN - OPUS4-58845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Integration of multi-scale workflows into the pyiron IDE
N2 - Material science problems have intrinsically multiscale and multiphysics characters, and require us to employ a combination of methods on different time and length scales to resolve critical features. Normally creating workflows that connect data in multiple scales and various methods is a cumbersome task. Pyiron, an integrated development environment (IDE) for material science, contains modules for the atomistic as well as continuum scale that make a seamless connection possible. To this end, it provides a high-level coherent language in a unified workflow platform to study materials, for example, with density functional theory (DFT) simulations in the same framework as with the finite element method (FEM). In this work, in addition to the introduction of different features in pyiron and its continuum module, a couple of exemplary workflows are demonstrated, bridging the scales in pyiron. One such workflow is analyzing the elastoplastic response of metallic alloys, where the elastic properties of the system are dependent on the atomistic composition and structure of the alloy. We use pyiron atomistics to model the dependence of elastic moduli on the atomistic composition of Al-Mg alloys. Benefiting from the integration of DAMASK in the continuum module of pyiron, the model can be used as an input to simulate the elastoplastic response of the alloy under various loadings. In addition, finite element simulations using the FEniCS package are currently integrated into the continuum module and will be demonstrated in the presentation.
T2 - FEMS Euromat Conference 2023
CY - Frankfurt/Main, Germany
DA - 03.09.2023
KW - Platform MaterialDigital
KW - Workflows
KW - Multiscale simulation
PY - 2023
AN - OPUS4-58847
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - High-throughput segregation analysis at ferritic Fe grain boundaries: from first principles
N2 - Understanding segregation to grain boundaries, and eventually their defect phase diagrams, is critical to enable rational grain boundary engineering for alloys design. Here, we discuss the progress and challenges one may face when generating such a database of defect-solute interactions, in the context of studying of grain boundary segregation of solutes and impurities in Fe GBs. To compute the large number of relevant defect-solute interactions we have performed high-throughput ab initio calculations using efficient and highly automated workflows using pyiron. We study has been performed across a representative set of coincident-site-lattice (CSL) type tilt GBs. Based on the large ab-initio datasets, we extract and analyse the chemical and structural trends observed in the solute segregation behaviour across the periodic table. The features which are most important in evaluating site segregation are presented and discussed.
T2 - DPG Frühjahrstagung der Sektion Kondensierte Materie
CY - Dresden, Germany
DA - 26.03.2023
KW - Ab initio simulations
KW - Defects
KW - Phase diagrams
PY - 2023
AN - OPUS4-58844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, X.
A1 - Zhang, J.
A1 - Wang, H.
A1 - Rogal, J:
A1 - Li, H.-Y.
A1 - Wei, S.-H.
A1 - Hickel, Tilmann
T1 - Defect-characterized phase transition kinetics
N2 - Phase transitions are a common phenomenon in condensed matter and act as a critical degree of freedom that can be employed to tailor the mechanical or electronic properties of materials. Understanding the fundamental mechanisms of the thermodynamics and kinetics of phase transitions is, thus, at the core of modern materials design. Conventionally, studies of phase transitions have, to a large extent, focused on pristine bulk phases. However, realistic materials exist in a complex form; their microstructures consist of different point and extended defects. The presence of defects impacts the thermodynamics and kinetics of phase transitions, but has been commonly ignored or treated separately. In recent years, with the significant advances in theoretical and experimental techniques, there has been an increasing research interest in modeling and characterizing how defects impact or even dictate phase transitions. The present review systematically discusses the recent progress in understanding the kinetics of defect-characterized phase transitions, derives the key mechanisms underlying these phase transitions, and envisions the remaining challenges and fruitful research directions. We hope that these discussions and insights will help to inspire future research and development in the field.
KW - Kinetics
KW - Atomistic models
KW - Phase transitions
KW - Defects
PY - 2022
DO - https://doi.org/10.1063/5.0117234
SN - 1931-9401
VL - 9
IS - 4
SP - 1
EP - 42
PB - AIP
CY - New York, NY
AN - OPUS4-56507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pierce, D.T.
A1 - Benzing, J.T.
A1 - Jiménez, J.A.
A1 - Hickel, Tilmann
A1 - Bleskov, I.
A1 - Keum, J.
A1 - Raabe, D.
A1 - Wittig, J.E.
T1 - The influence of temperature on the strain-hardening behavior of Fe-22/25/28Mn-3Al-3Si TRIP/TWIP steels
N2 - The influence of temperature and stacking fault energy (SFE) on the strain-hardening behavior and critical resolved shear stress for twinning was investigated for three Fe–22/25/28Mn–3Al–3Si wt.% transformation- and twinning-induced plasticity (TRIP/TWIP) steels. The SFEs were calculated by two different methods, density functional theory and statistical thermodynamic modeling. The dislocation structure, observed at low levels of plastic deformation, transitions from “planar” to “wavy” dislocation glide with an increase in temperature, Mn content, and/or SFE. The change in dislocation glide mechanisms from planar to wavy reduces the strain hardening rate, in part due to fewer planar obstacles and greater cross slip activity. In addition, the alloys exhibit a large decrease in strength and ductility with increasing temperature from 25 to 200 °C, attributed to a substantial reduction in the thermally activated component of the flow stress, predominate suppression of TRIP and TWIP, and a significant increase in the critical resolved shear stress for mechanical twinning. Interestingly, the increase in SFE with temperature had a rather minor influence on the critical resolved shear stress for mechanical twinning, and other temperature dependent factors which likely play a more dominant role are discussed.
KW - TWIP Steel
KW - TRIP Steel
KW - Stacking fault energy
KW - Plasticity mechanism
KW - Twinning
PY - 2022
DO - https://doi.org/10.1016/j.mtla.2022.101425
SN - 2589-1529
VL - 22
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-56508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - Optimally rejuvenated model binary glasses
N2 - Using the creation relaxation algorithm developed for the atomistic modeling of the high-dose irradiation limit of crystalline systems, we explore the limits of the structural rejuvenation of a highly excited model binary glass. This high-energy athermal amorphous structure exhibits a direct transition to homogeneous plastic flow and a microstructure that is largely insensitive to this flow, being characterized by a porous system-spanning network of minimally frustrated structural motifs. The observed homogeneous plasticity is mediated by the same string-like structural excitations, which mediate structural relaxation and microplasticity at finite temperature in more relaxed structures. This highly rejuvenated structural asymptote is not far from the structural state of regions, which have experienced athermal shear localization in more relaxed samples, suggesting an optimally rejuvenated glassy structure will always be limited by that produced by shear localization.
KW - Metallic glasses
KW - Creation-relaxation algorithm
KW - Shear
PY - 2022
DO - https://doi.org/10.1103/PhysRevMaterials.6.125604
VL - 6
IS - 12
SP - 1
EP - 13
PB - American Physical Society
AN - OPUS4-56741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kar, S.
A1 - Ikeda, Yuki
A1 - Lünser, K.
A1 - Woodcock, Th. G.
A1 - Nielsch, K.
A1 - Reith, H.
A1 - Maaß, Robert
A1 - Fähler, S.
T1 - Growth Twins and Premartensite Microstructure in Epitaxial Ni-Mn-Ga Films
N2 - Magnetic shape memory alloys have been examined intensively due to their multifunctionality and multitude of physical phenomena. For both areas, epitaxial films are promising since the absence of grain boundaries is beneficial for applications in microsystems and they also allow to understand the influence of a reduced dimension on the physical effects. Despite many efforts on epitaxial films, two particular aspects remain open.
First, it is not clear how to keep epitaxial growth up to high film thickness, which is required for most microsystems.
Second, it is unknown how the microstructure of premartensite, a precursor state during the martensitic transformation, manifests in films and differs from that in bulk.
Here, we focus on micrometer-thick austenitic Ni-Mn-Ga films and explain two distinct microstructural features by combining high-resolution electron microscopy and X-ray diffraction methods. First, we identify pyramid-shaped defects, which originate from {1 1 1} growth twinning and cause the breakdown of epitaxial growth. We show that a sufficiently thick Cr buffer layer prevents this breakdown and allows epitaxial growth up to a thickness of at least 4 μm. Second, premartensite exhibits a hierarchical microstructure in epitaxial films. The reduced dimension of films results in variant selection and regions with distinct premartensite variants, unlike its microstructure in bulk.
KW - Alloy
KW - Epitaxial films
KW - Hierarchical microstructure Premartensite
KW - Twinning
KW - Magnetic shape memory
PY - 2023
DO - https://doi.org/10.1016/j.actamat.2023.118902
SN - 1359-6454
VL - 252
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-57301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, A.
A1 - Ott, C.
A1 - Pechimuthu, Dinesh
A1 - Moosavi, Robabeh
A1 - Stoica, M.
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - Shear-band cavitation determines the shape of the stress-strain curve of metallic glasses
N2 - Metallic glasses are known to have a remarkably robust yield strength, admitting Weibull moduli as high as for crystalline engineering alloys. However, their postyielding behavior is strongly varying, with large scatter in both flow stress levels and strains at failure. Using x-ray tomography, we reveal how a strain-dependent internal evolution of shear-band cavities underlies this unpredictable postyielding response.We demonstrate how macroscopic strain softening coincides with the first detection of internal shear-band cavitation. Cavity growth during plastic flow is found to follow a power law, which yields a fractal dimension and a roughness exponent in excellent agreement with self-similar surface properties obtained after fracture. These findings demonstrate how internal microcracking coexists with shear-band plasticity along the plastic part of a stress-strain curve, rationalizing the large variability of plastic flow behavior seen for metallic glasses.
KW - Shear-band cavitation
KW - Metallic glasses
PY - 2023
DO - https://doi.org/10.1103/PhysRevMaterials.7.023602
SN - 2475-9953
VL - 7
IS - 2
SP - 1
EP - 11
PB - American Physical Society
AN - OPUS4-57042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Riechers, Birte
A1 - Maaß, Robert
T1 - nanoindentation data associated with the publication "On the elastic microstructure of bulk metallic glasses" in Materials&Design 2023
N2 - This dataset consists of indentation data measured with a conospherical tip in a Hysitron-Bruker TI980 Nanoindenter on the surface of a <100> Silicon wafer and a polished cross-sectional cut of a Zr65Cu25Al10 bulk metallic glass.
It is associated with the following publication:
Birte Riechers, Catherine Ott, Saurabh Mohan Das, Christian H. Liebscher, Konrad Samwer, Peter M. Derlet and Robert Maass "On the elastic microstructure of bulk metallic glasses" Materials and Design xxx, (2023) 111929. https://doi.org/10.1016/j.matdes.2023.111929
All experimental information can be found in this paper and in the accompanying supplementary information.
This electronic version of the data was published on the "Zenodo Data repository" found at http://zenodo.org/deposit in the community "Bundesanstalt fuer Materialforschung und -pruefung (BAM)".
The authors have copyright to these data. You are welcome to use the data for further analysis, but are requested to cite the original publication whenever use is made of the data in publications, presentations, etc.
Any questions regarding the data can be addressed to birte.riechers@bam.de who would also appreciate a note if you find the data useful.
KW - Metallic glasses
KW - Nanoindentation
KW - Elastic microstructure
PY - 2023
DO - https://doi.org/10.5281/zenodo.7818224
PB - Zenodo
CY - Geneva
AN - OPUS4-57352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Application of density functional theory in the context of phase diagram modelling
N2 - In this presentation the fundamentals of density functional theory are explained in the context of phase diagram modelling. A special focus is on the Ni-Mg phase diagram.
T2 - 7th MSIT Winter School
CY - Kreuth, Germany
DA - 12.03.2023
KW - Ab initio simulations
KW - Thermodynamics
KW - Phase diagrams
PY - 2023
AN - OPUS4-58855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Intermittent cluster dynamics and temporal fractional diffusion in a bulk metallic glass
N2 - Inspired by the ability to track atomic-scale dynamics with x-ray photon correlation spectroscopy (XPCS)1 and recent results of long-term atomistic simulations on material transport2, we reveal here an unprecedented spectrum of short- and long-term relaxation dynamics. Tracked along a 300 000 s long isotherm at 0.98Tg, a Zr-based bulk metallic glass exhibits temporal fluctuations that persist throughout the entire isotherm, demonstrating a continuous heterogeneous dynamics at the probed length scale. In concert with microsecond molecular dynamic simulations, we identify intermittent cluster dynamics as the origin for temporal signatures in the corresponding intensity cross-correlations. Despite temporally heterogeneous aging, the Kohlrausch-Williams-Watts functions is well suited to capture the average intermediate relaxation time regime, but at very long time scales an asymptotic power-law better describes the data. This indicates anomalous diffusion and gives overall strong evidence for temporal fractional diffusion in metallic glasses. We discuss these results in terms of the underlying structural fast and slow relaxation modes and their manifestation in the temporal form of the structural decorrelations.
T2 - 9th IDMRCS
CY - Chiba, Japan
DA - 12.08.2023
KW - Metallic glass
KW - Transport
KW - Structure
KW - Dynamics
PY - 2023
AN - OPUS4-60696
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - Cluster dynamics and anomalous transport in metallic glasses
N2 - Quenching a metallic liquid sufficiently fast can give rise to an amorphous solid, typically referred to as a metallic glass. This out-of-equilibrium material has a long suite of remarkable mechanical and physical properties but suffers from property deterioration via structural relaxation. As a function of time, relaxation may indeed constitute significant threads to safe applications. Consequently, relaxation of glasses has a long history across different amorphous materials and typical characterization methods promote a picture of gradually evolving and smooth relaxation, as for example obtained from mechanical spectroscopy. However, the true structural dynamics and underlying mechanisms remain far from understood and have hampered a physically informed atomic-scale picture of transport and physical aging of glasses.
Here we exploit the ability to track atomic-scale dynamics with x-ray photon correlation spectroscopy (XPCS) and resolve an unprecedented spectrum of short- and long-term relaxation time scales in metallic glasses. Conducted across temperatures and under the application of stress, the results reveal anything else than smooth aging and gradual energy minimization. In fact, temporal fluctuations persist throughout isothermal conditions over several hundred thousand of seconds, demonstrating heterogeneous dynamics at the atomic scale. In concert with microsecond molecular dynamic simulations, we identify possible mechanisms of correlated atomic-scale dynamics that can underly the temporal fluctuations and structural decorrelations. Despite temporally heterogeneous, the Kohlrausch-Williams-Watts functions is well suited to capture the average intermediate relaxation time regime, but at very long time scales an asymptotic power-law emerges. This indicates anomalous diffusion and gives overall strong evidence for temporal fractional diffusion in metallic glasses. We discuss these results in terms of the structural fast and slow relaxation modes as well as a true microstructure in metallic glasses.
T2 - Department Seminar OSU 2023
CY - Columbus, OH, USA
DA - 22.09.2023
KW - Metallic glass
KW - Transport
KW - Structure
KW - Dynamics
PY - 2023
AN - OPUS4-60699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hickel, Tilmann
T1 - Research data infrastructures as enablers for materials design
N2 - Suitable material solutions are of key importance in designing and producing components for engineering systems – either for functional or structural applications. Materials data are generated, transferred, and introduced at each step along the complete life cycle of a component. A reliable materials data space is therefore crucial in the digital transformation, both in academia and industry.
Therefore, the consortium NFDI MatWerk aims to develop a sustainable infrastructure for the standardized digital representation of materials science and engineering (MatWerk). The goal is to seamlessly integrate decentralized data and metadata, experimental and computational workflows, and a materials ontology to maximize interoperability and reproducibility of materials data processing. To this end, data use profiles of participant projects from different sub-disciplines are analyzed to identify the most relevant scientific scenarios within MatWerk.
Similarly, the Plattform MaterialDigital (PMD) is committed to provide a prototypical infrastructure for the digitalization of materials in an industrial context implemented by decentralized data servers, semantic data schemas and digital workflows. The standards, methods, and tools developed within the PMD are deployed and consolidated within the context of currently more than 20 BMBF-funded academic and industrial research consortia. Scientific workflow environments represent a major focus area, including efforts to improve the definition and representation of digital workflows, as well as their distribution in form of a workflow store.
In this presentation we will describe the overarching visions behind these initiatives, their status, and progress of dissemination with a focus on the workflow activities. Following the philosophy of both consortia, specific examples will be used to demonstrate innovative and pragmatic solutions.
T2 - MCIC 2023 – 5th Materials Chain International Conference
CY - Bochum, Germany
DA - 31.08.2023
KW - Digital Infrastructure
KW - Workflows
KW - Integrated Development Environment
PY - 2023
AN - OPUS4-58852
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maaß, Robert
T1 - On an unusual career path and unusual transport in metallic glasses
N2 - Planning an academic career is a bit like enjoying a box of chocolate – you never know what you are going to get next. In this talk, I will begin with sharing how luck, difficult decisions, fate, and family constraints affected my career path across continents, universities, the private sector, and to becoming a director at a national laboratory. This journey was certainly not planned and highlights how opportunities and compromises together allow you to make much more out of your engineering degree than you ever have dreamed of.
After this unusual journey as a materials scientist, I am transitioning to the technical part of my talk, where we will discuss transport in metallic glasses. This out-of-equilibrium material has a long suite of remarkable mechanical and physical properties but suffers from property deterioration via physical aging. As a function of time, relaxation may indeed constitute significant threads to safe applications, such as a complete loss of toughness.
In the search for a physical understanding of aging, we exploit here the ability to track atomic-scale dynamics with coherent x-ray scattering. Conducted across temperatures and under the application of stress, the results reveal unexpected transport. In concert with microsecond molecular dynamic simulations, we identify possible mechanisms of atomic-scale dynamics that underly physical aging of metallic glasses. We find that classical Kohlrausch-Williams-Watts behavior is only suited for the short relaxation-time regime, whereas anomalous diffusion emerges at practically relevant times. We discuss these results in terms of the structural relaxation modes and propose a picture of a true microstructure in metallic glasses.
T2 - Department Seminar IIT Delhi 2023
CY - Delhi, India
DA - 15.12.2023
KW - Metallic glass
KW - Transport
KW - Structure
KW - Dynamics
PY - 2023
AN - OPUS4-60649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Seamless Science with the Platform MaterialDigital (PMD): Demonstration of Semantic Data Integration as Good Practices
N2 - Following the new paradigm of materials development, design, and optimization, digitalization is the main goal in materials sciences and engineering (MSE) which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web technologies (SWT) are used since they allow for machine-actionable and human-readable knowledge representations needed for data management, retrieval, and (re)use.
The project ‘platform MaterialDigital’ (PMD) aims to bring together and support interested parties from both industrial and academic sectors in a sustainable manner in solving digitalization tasks and implementing digital solutions. Therefore, the establishment of a virtual material data space and the systematization of the handling of hierarchical, process-dependent material data are focused. Core points to be dealt with are the development of agreements on data structures and interfaces implemented in distinct software tools and to offer users specific support in their projects. Furthermore, the platform contributes to a standardized description of data processing methods in materials research. In this respect, selected MSE methods are semantically represented on a prototypical basis which are supposed to serve as best practice examples with respect to knowledge representation and the creation of knowledge graphs used for material data.
Accordingly, this poster presentation illustrates demonstrators developed and deployed within the PMD project. Semantically anchored using the mid-level PMD Core Ontology (PMDco), they address data transformation leading to a novel data management which is based on semantic integrated data. The PMD data acquisition pipeline (DAP), which is fueled by traditional, diverse data formats, and a pipeline applying an electronic laboratory notebook (ELN) as data source are displayed. Additionally, the efficient combination of diverse datasets originating from different sources is demonstrated by the representation of a use case dealing with the well-known Orowan relation.
T2 - 9. Dresdner Werkstoffsymposium
CY - Dresden, Germany
DA - 16.05.2024
KW - Semantic Data
KW - Data Integration
KW - Plattform MaterialDigital
KW - Demonstrators
KW - Electronic Lab Notebook
PY - 2024
AN - OPUS4-60102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Ott, C.
A1 - Das, S. M.
A1 - Liebscher, C.
A1 - Samwer, K.
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - On the elastic microstructure of bulk metallic glasses
N2 - Metallic glasses (MGs) are known to be structurally heterogeneous at the nanometer (nm) scale. In addition, elastic property mapping has indicated the presence of at least an order-of-magnitude larger length scales, of which the origin continues to remain unknown. Here we demonstrate the existence of an elastic decorrelation length of the order of 100 nm in a Zr-based bulk MG using spatially resolved elastic property mapping via nanoindentation. Since compositional modulations sufficiently large to account for this elastic microstructure were not resolved by analytical scanning-transmission electron microscopy, chemical phase separation such as spinodal decomposition cannot explain their occurrence as previously suggested. Instead, we argue that the revealed long-range elastic modulations stem from structural variations affecting the local density. These emerge during solidification and are strongly influenced by the cooling constraints imposed on bulk MGs during the casting process.
KW - Metallic glasses
KW - Nanoindentation
KW - Elastic microstructure
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573504
DO - https://doi.org/10.1016/j.matdes.2023.111929
SN - 0264-1275
VL - 229
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-57350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
A1 - Wallis, Theophilus
A1 - Ikeda, Yuki
A1 - Saikia, U.
A1 - Ahmadian, A.
A1 - Liebscher, C.
A1 - Hickel, Tilmann
A1 - Maaß, Robert
T1 - Giant segregation transition as origin of liquid metal embrittlement in the Fe-Zn system
N2 - A giant Zn segregation transition is revealed using CALPHAD-integrated density-based modeling of segregation into Fe grain boundaries (GBs). The results show that above a threshold of only a few atomic percent Zn in the alloy, a substantial amount of up to 60 at.% Zn can segregate to the GB. We found that the amount of segregation abruptly increases with decreasing temperature, while the Zn content in the alloy required for triggering the segregation transition decreases. Direct evidence of the Zn segregation transition is obtained using high-resolution scanning transmission electron microscopy. Base on the model, we trace the origin of the segregation transition back to the low cohesive energy of Zn and a miscibility gap in Fe-Zn GB, arising from the magnetic ordering effect, which is confirmed by ab-initio calculations. We also show that the massive Zn segregation resulting from the segregation transition greatly assists with liquid wetting and reduces the work of separation along the GB. The current predictions suggest that control over Zn segregation, by both alloy design and optimizing the galvanization and welding processes, may offer preventive strategies against liquid metal embrittlement.
KW - CALPHAD
KW - Microstructure Design
KW - Grain boundary engineering
KW - Steels
KW - Density-based Model
KW - Segregation Engineering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584292
DO - https://doi.org/10.1016/j.scriptamat.2023.115758
SN - 1359-6462
SN - 1872-8456
VL - 238
SP - 1
EP - 5
PB - Elsevier
CY - Amsterdam
AN - OPUS4-58429
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lorenzoni, Renata
A1 - Cunningham, Patrick
A1 - Fritsch, Tobias
A1 - Schmidt, Wolfram
A1 - Kruschwitz, Sabine
A1 - Bruno, Giovanni
T1 - Microstructure analysis of cement‑biochar composites
N2 - The use of biochar as a concrete constituent has been proposed to reduce the massive carbon footprint of concrete. Due to the low density and complex porosity of biochar, microstructural analysis of Portland cement-biochar composites is challenging.
This causes challenges to the improvement of the micro-scale understanding of biochar composite behavior. This work advances the microstructural understanding of Portland cement composites with 0, 5, and 25 volume percent (vol%) of cement replaced with wood biochar by applying common characterization techniques of mercury intrusion porosimetry (MIP), gas sorption, scanning electron microscopy, and isothermal heat flow calorimetry (HFC) in conjunction with 1H nuclear magnetic resonance (NMR) and micro-X-ray computed tomography (XCT) analysis techniques. The combination of these techniques allows a multi-scale investigation of the effect of biochar on the microstructure of cement paste. NMR and XCT techniques allow the observation and quantification of the pore space. HFC and MIP confirmed that biochar absorbs moisture and reduces the effective water-cement ratio. Gas sorption, MIP, and NMR shows that 5 vol% replacement does not significantly affect the gel and capillary pore structures. Results from XCT (supported by MIP and NMR) show that biochar can reduce the formation of larger pores.
Importantly, XCT results suggest that biochar can act as a flaw in the microstructure which could explain reductions in the mechanical properties. Overall, the mechanical properties already analyzed in the literature are consistent with the microstructural changes observed, and these results highlight the need to carefully tailor the volume fraction of biochar to control its effect on the paste microstructure.
KW - Cementitious materials
KW - Biochar
KW - Microstructure
KW - Porosity
KW - Pore size distribution
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610900
DO - https://doi.org/10.1617/s11527-024-02452-5
VL - 57
SP - 16
EP - 175
PB - Springer
AN - OPUS4-61090
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiedeitz, M.
A1 - Schmidt, Wolfram
A1 - Härder, M.
A1 - Kränkel, T.
T1 - Performance of rice husk ash as supplementary cementitious material after production in the field and in the lab
N2 - Supplementary cementitious materials (SCM) can reduce the total amount of Portland cement clinker in concrete production. Rice husk ashes (RHA) can be converted from an agricultural by-product to a high-performance concrete constituent due to a high amount of reactive silica with pozzolanic properties if they are burnt under controlled conditions. The way and duration of combustion, the cooling process as well as the temperature have an effect on the silica form and thus, the chemical and physical performance of the RHA. Various studies on the best combustion technique have been published to investigate the ideal combustion techniques. Yet, the process mostly took place under laboratory conditions. Investigating the difference between the performance of RHA produced in a rural environment and laboratory conditions is useful for the assessment and future enhancement of RHA production, and its application both as building material, for example in rural areas where it is sourced in large quantities, and as additive for high performance concrete. Thus, the paper presents a comparison between RHA produced under rudimentary conditions in a self-made furnace in the rural Bagamoyo, Tanzania and under controlled laboratory conditions at the Technical University of Munich, Germany, with different combustion methods and temperatures. In a second step, RHA was ground to reach particle size distributions comparable to cement. In a third step, cement pastes were prepared with 10%, 20% and 40% of cement replacement, and compared to the performance of plain and fly ash blended cement pastes. The results show that controlled burning conditions around 650 °C lead to high reactivity of silica and, therefore, to good performance as SCM. However, also the RHA burnt under less controlled conditions in the field provided reasonably good properties, if the process took place with proper burning parameters and adequate grinding. The knowledge can be implemented in the field to improve the final RHA performance as SCM in concrete.
KW - Rice husk ash
KW - Agricultural by-product
KW - Supplementary cementitious material
KW - Waste management
KW - Carbon dioxide emissions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568953
DO - https://doi.org/10.3390/ma13194319
SN - 1996-1944
VL - 13
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-56895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Munsch, Sarah Mandy
A1 - Telong, Melissa
A1 - Schmidt, Wolfram
A1 - Bintz, Thilo
A1 - Fladt, Matthias
A1 - Stelzner, Ludwig
T1 - The NMR core analyzing TOMograph: A multi-functional tool for non-destructive testing of building materials
N2 - NMR is becoming increasingly popular for the investigation of building materials as it is a non-invasive technology that does not require any sample preparation nor causes damage to the material. Depending on the specific application it can offer insights into properties like porosity and spatial saturation degree as well as pore structure. Moreover it enables the determination of moisture transport properties and the (re-)distribution of internal moisture into different reservoirs or chemical phases upon damage and curing. However, as yet most investigations were carried out using devices originally either designed for geophysical applications or the analysis of rather homogeneous small scale (< 10 mL) samples. This paper describes the capabilities of an NMR tomograph, which has been specifically optimized for the investigation of larger, heterogeneous building material samples (diameters of up to 72 mm, length of up to 700 mm) with a high flexibility due to interchangeable coils allowing for a high SNR and short echo times (50 - 80 m s).
KW - Fire spalling
KW - Moisture transport
KW - Concrete
KW - Cement hydration
KW - Sensitivity
KW - Supplementary cementitous materials
KW - Frost salt attack
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573755
DO - https://doi.org/10.1016/j.mrl.2023.03.004
SN - 2097-0048
VL - 3
IS - 3
SP - 207
EP - 219
PB - Elsevier B.V.
AN - OPUS4-57375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cunningham, Patrick
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
T1 - Revealing Value from Bioderived Polymers: Effects of Locally Sourced Polysaccharides on the Rheology of Limestone Mixtures
N2 - Admixtures are important constituents to enhance the performance of concrete. They allow for more efficient use of binders which can mitigate negative environmental impacts from producing cement-based materials. Commonly used rheology modifying agents like polycarboxylate ethers or cellulose ethers are synthetic or semi-synthetic, respectively. This requires additional energy consumption for their production and global supply chains particularly for many developing regions, which will be large consumers of concrete in the future. However, many locally available bio-based polysaccharides could be effectively used instead. These polymers are often overlooked by engineers and scientists due to their limited distribution and inherent complexity, yet they represent an underleveraged source of precursors for admixtures. This study investigates the action mechanisms of some bio-based rheology modifying agents, i.e., acacia gum and miscanthus gum, and provides a comparison to a conventionally modified starch. The results show that the mechanism of action of these polymers is closely related to the composition of the mixture, mixing regime, and the composition of the aqueous phase. Depending on the agent, either plasticizing or stabilizing effects on rheology can be revealed.
T2 - ICBBM: International Conference on Bio-Based Building Materials
CY - Vienna, Austria
DA - 21.06.2023
KW - Polysaccharides
KW - Superplasticizers
KW - Hydration
KW - Cement
PY - 2023
DO - https://doi.org/10.1007/978-3-031-33465-8_60
SN - 2211-0852
VL - 45
SP - 782
EP - 792
PB - Springer Nature Switzerland AG
CY - Switzerland
AN - OPUS4-58726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
A1 - Lorenzoni, Renata
A1 - Telong, Melissa
A1 - Lauinger, Robert
A1 - Munsch, Sarah Mandy
A1 - Schmidt, Wolfram
T1 - Investigation of the hydration of clinker-reduced cementitious binders by 1H NMR
N2 - In this paper, we demonstrate the value of 1H NMR relaxometry for studying the hydration of clinker-reduced, more climate-friendly cementitious binders. The results were obtained on typical CEM I cements and sister samples containing two different reactive agricultural ashes as well as non-reactive biochars as supplementary cementitious materials. The findings prove that time-resolved NMR measurements provide valuable additional information when combined with classical heat flow calorimetry.
T2 - International Conference on Electromagnetic Wave Interaction with Water and Moist Substances of the International Society for Electromagnetic Aquametry (ISEMA) 2023
CY - Brisbane, Ausralia
DA - 25.09.2023
KW - Carbon emission
KW - 1H NMR relaxometry
KW - Heat flow calorimetry
KW - Cement, hydration
KW - Clinker reduction
PY - 2023
SP - 1
EP - 3
AN - OPUS4-58936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fini, E. H.
A1 - Poulikakos, L.
A1 - de Claville Christiansen, J.
A1 - Schmidt, Wolfram
A1 - Parast, M. M.
T1 - Toward sustainability in the built environment: An integrative approach
N2 - The built environment significantly impacts the health of individuals and populations in various ways. The health and durability of the built environment are intertwined with availability ofnaturally occurring and man-made resources and their supply chains. Therefore, resource con servation is a key to ensure sustainability of built environments. Many industrial wastes can be turned into valuable resources for reuse in construction of the built environment. For instance, biowaste (woody/ leafy biomass and animal waste) have been used to make construction adhesives (Fini et al., 2011), some urban wastes have been used in road construction (Poulikakos et al., 2017; Schmidt et al., 2021), end of life plastics and polymers have made their way to roadway construction, bio-oils and algae harvested from wastewater treatment plants has been used to make antiaging for outdoor building elements to mitigate UV aging (Kabir et al., 2021); sulfur has been used as an extender in asphalt and recycled mineral powders such as silica and alumina have been used to increase strength and durability against acidic compounds (Fini et al., 2019). These are just a few examples of recycling venues with beneficial uses in the built environment.
The construction and operation of the built environment and the traffic that it attracts or facilitates significantly contribute to the emis sion of greenhouse gasses (GHG) and cause air pollution. The direct and indirect impacts of GHG and air pollutants on the environment and so cieties have been weil established. The built environment can be used as a powerful platform not only for recycling and resource conservation but also to remove near-ground gaseous contaminants. This can be done via tailored design and engineering of adsorptive construction materials via recycling of waste materials. For instance, advanced sorbent systems can be made for removing C02, H2S, and formaldehyde from air. This re quires tailored sorbent design, topology optimization, and catalytic conversion of collected gaseous compounds to name a few.
This special issue covers innovative materials, methods, and man agement practices which aim to simultaneously address durability ofthe built environment, air quality, resource conservation, and supply chain resilience. Such innovative materials, methods, and management prac tices will transform the built environment into not only an active contributor to no waste, no pollution for healthy environment, but also a medium that converts the waste and pollution into beneficial products for use in the built environment, thereby promoting resource conser vation. Followings are examples of topics that the special issue is interested in:
• Venuses to advance resource conservation specifically via novel ap proaches in the built environment.
• Innovative construction materials for passive or active adsorption of harmful gaseous emissions to conserve air, energy, and water.
• Advanced materials, methods, and management practices to pro mote well-being of the built environment.
• Smart buildings to promote resource conservation.
• Research convergence in the built environment for zero waste, zero pollution economy.
KW - Impacts
KW - Resource
PY - 2021
DO - https://doi.org/10.1016/j.resconrec.2021.105676
VL - 172
SP - 1
EP - 2
PB - Elsevier
AN - OPUS4-58402
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bessaies-Bey, H.
A1 - Khayat, K. H.
A1 - Palacios, M.
A1 - Schmidt, Wolfram
A1 - Roussel, N.
T1 - Viscosity modifying agents: Key components of advanced cement-based materials with adapted rheology
N2 - Viscosity modifying agents (VMAs) are essential ingredients for the production of flowable cement-based materials. This paper presents an overview of commonly used VMAs and attempts to shed some light on the underlying physics at the origin of their mechanisms of action. The main molecular parameters of VMA controlling the rheological properties of the cement pore solution are highlighted. As the mechanisms of action of VMAs in cement-based materials are closely related to their affinity with the surface of cement particles, the adsorption of the main VMA types is discussed. The effect of VMAs on flow properties and stability of cement-based materials is presented for VMAs added without any superplasticizer, and then in systems incorporating both VMAs and superplasticizers. Finally, the effect of VMAs in enhancing concrete properties to secure adequate performance of different construction applications, and perspectives for future developments of novel cement-based materials made with VMAs are showcased.
KW - Viscosity modifying agents
KW - Cement
KW - Stability
KW - Rheology
KW - Working mechanism
KW - Compatibility
PY - 2022
DO - https://doi.org/10.1016/j.cemconres.2021.106646
VL - 152
SP - 1
EP - 20
PB - Elsevier
AN - OPUS4-58396
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
T1 - Investigation of the hydration of clinker-reduced cementitious binders by 1H NMR
N2 - In this paper, we demonstrate the value of 1H NMR
relaxometry for studying the hydration of clinker-reduced, more
climate-friendly cementitious binders. The results were obtained
on typical CEM I cements and samples containing two different
reactive agricultural ashes as well as non-reactive biochars as
supplementary cementitious materials. The findings prove that
time-resolved NMR measurements provide valuable additional
information when combined with classical heat flow calorimetry.
T2 - ISEMA Down Under 2023
CY - Brisbane, Australia
DA - 25.09.2023
KW - 1H NMR relaxometry
KW - Heat flow calorimetry
KW - Clinker reduction, carbon emission
KW - Cement
KW - Hydration
PY - 2023
AN - OPUS4-58569
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Carvello, J. M. F.
A1 - Carvalho Fontes, W.
A1 - de Azevedo, C. F.
A1 - Brigolini, G. J.
A1 - Schmidt, Wolfram
A1 - Fiorotti Peixoto, R. A.
T1 - Enhancing the eco-efficiency of concrete using engineered recycled mineral admixtures and recycled aggregates
N2 - Non-conventional densely packed concrete mixtures are proposed and evaluated in this paper using engineered recycled mineral admixtures and recycled aggregates obtained from steel slag, quartz mining tailings, and quartzite mining tailings. High fines content sand-concretes containing coarser- and finer-than-cement recycled powders were designed to obtain blends with broader particle-size ranges and improved packing density. As a result, compressive strength up to 99 MPa, cement intensity up to 2.33 kg/m³/MPa, and consumption of recycled material up to 95 vol% were obtained. Compressive strengths up to 66 MPa and cement intensity up to 2.34 kg/m³/MPa were also obtained with the addition of coarse aggregates to such sand-concrete mixtures, with consumption of recycled material up to 96.5%. The results launch new insights on the role of recycled admixtures and aggregates on the mixture design of cement-based composites regarding efficiency improvement and technological performance.
KW - Low-cement concrete
KW - Recycled mineral admixture
KW - Basic oxygen furnace slag
KW - Quartzite mining tailing
KW - Packing density
PY - 2020
DO - https://doi.org/10.1016/j.jclepro.2020.120530
VL - 257
SP - 1
EP - 12
PB - Elsevier
AN - OPUS4-58401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kar, Satyakam
A1 - Ikeda, Yuki
A1 - Nielsch, Kornelius
A1 - Reith, Heiko
A1 - Maaß, Robert
A1 - Fähler, Sebastian
T1 - Multiferroic Microstructure Created from Invariant Line Constraint
N2 - Ferroic materials enable a multitude of emerging applications, and optimum functional properties are achieved when ferromagnetic and ferroelectric properties are coupled to a first‐order ferroelastic transition. In bulk materials, this first‐order transition involves an invariant habit plane, connecting coexisting phases: austenite and martensite. Theory predicts that this plane should converge to a line in thin films, but experimental evidence is missing. Here, the martensitic and magnetic microstructure of a freestanding epitaxial magnetic shape memory film is analyzed. It is shown that the martensite microstructure is determined by an invariant line constraint using lattice parameters of both phases as the only input. This line constraint explains most of the observable features, which differ fundamentally from bulk and constrained films. Furthermore, this finite‐size effect creates a remarkable checkerboard magnetic domain pattern through multiferroic coupling. The findings highlight the decisive role of finite‐size effects in multiferroics.
KW - Epitaxial films
KW - Finite-size effects
KW - Multiferroics
KW - Martensite
KW - Magnetic shape memory alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637910
DO - https://doi.org/10.1002/adfm.202416638
SN - 1616-301X
VL - 35
IS - 10
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-63791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maaß, Robert
A1 - Derlet, P.
T1 - Micro-plasticity in a fragile model binary glass
N2 - Atomistic deformation simulations in the nominally elastic regime are performed for a model binary glass with strain rates as low as 10 4 /s (corresponding to 0.01 shear strain per 1 μs). A strain rate dependent elastic softening due to a micro-plasticity is observed, which is mediated by thermally-activated localized structural transformations (LSEs). A closer inspection of the atomic-scale structure indicates the material response is distinctly different for two types of local atomic environments. A system spanning iscosahe- drally coordinated substructure responds purely elastically, whereas the remaining substructure admits both elastic and microplastic evolution. This leads to a heterogeneous internal stress distribution which, upon unloading, results in negative creep and complete residual-strain recovery. A detailed structural analysis in terms of local stress, atomic displacement, and SU(2) local bonding topology shows such mi- croscopic processes can result in large changes in local stress and are more likely to occur in geomet- rically frustrated regions characterized by higher free volume and softer elastic stiffness. The thermally- activated LSE activity also mediates structural relaxation, and in this way should be distinguished from stress-driven shear transformation activity which only rejuvenates glass structure. The frequency of LSE activity, and therefore the amount of micro-plasticity, is found to be related to the degree to which the glassy state is relaxed. These insights shed atomistic light onto the structural origins that may govern re- cent experimental observations of significant structural evolution in response to elastic loading protocols.
KW - Molecular dynamics
KW - Bulk metallic glasses
KW - Plasticity
KW - Residual strains
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523782
DO - https://doi.org/10.1016/j.actamat.2021.116771
VL - 209
SP - 116771
PB - Elsevier Ltd.
AN - OPUS4-52378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Yuan, R.
A1 - Chakraborty, A.
A1 - Ghassemi-Armaki, H.
A1 - Zuo, J. M.
A1 - Maaß, Robert
T1 - Early stages of liquid-metal embrittlement in an advanced high-strength steel
N2 - Grain-boundary degradation via liquid-metal embrittlement (LME) is a prominent and long-standing failure process in next generation advanced high-strength steels. Here we reveal, well ahead of the crack tip, the presences of nano-scale grains of intermetallic phases in Zn-infiltrated but uncracked grain boundaries with scanning- and 4D transmission electron microscopy. Instead of the often-reported Znrich Fe-Zn intermetallics, the nano-scale phase in the uncracked infiltrated grain boundaries is identified as the G-phase, and its presence reveals the local enhancement of strain heterogeneities in the grain boundary network. Based on these observations, we argue that intermetallic phase formation is not occurring after cracking and subsequent liquid Zn infiltration but is instead one of the primary nanoscopic drivers for grain-boundary weakening and crack initiation. These findings shift the focus of LME from micro- and meso-scale crack investigations to the very early stages immediately following Zn diffusion, after which secondary phase nucleation and growth emerge as the root-cause for failure.
KW - Advanced high strength steels
KW - Liquid metal embrittlement
KW - Transmission electron microscopy
KW - 4-Dimensional scanning transmission
KW - electron microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539716
DO - https://doi.org/10.1016/j.mtadv.2021.100196
SN - 2590-0498
VL - 13
IS - 196
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-53971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maaß, Robert
T1 - Beyond Serrated Flow in Bulk Metallic Glasses: What Comes Next?
N2 - This manuscript is based on an oral contribution to the TMS 2020 annual meeting and is dedicated to Prof. Peter Liaw, who for decades has shown great interest in serrated plastic flow.
Here we will focus on the case of bulk metallic glasses, and begin with briefly summarizing some aspects of serrated and non-serrated inhomogeneous flow—a phenomenon that has perplexed materials scientists for decades. Four directions of research are identified that emerged out of the desire to fundamentally understand the intermittent inhomogeneous flow response. These research directions gear away from the phenomenological stress–strain behavior but put the underlying shear defect into focus. Unsolved problems and future research topics are discussed.
KW - Non-serrated inhomogeneous flow
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513106
DO - https://doi.org/10.1007/s11661-020-05985-w
SN - 1073-5623
SP - 1
EP - 11
PB - Springer Nature
AN - OPUS4-51310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wallis, Theophilus
A1 - Darvishi Kamachali, Reza
T1 - Density-based phase field modelling of the interplay between grain boundary segregation transition and structure
N2 - Grain boundary (GB) chemical and structural variations can significantly influence materials performance. The former is generally ascribed to the structural gradient between the grain and GB. While GB segregation may be accompanied by chemical and structural variations, clear insights about the GB’s thermodynamic phase behaviour upon coupling between its chemistry and structure is lacking. Using the CALPHAD integrated density-based phase field model, we study the co-evolution of GB’s structure and segregation in Fe-Mn alloys. We found that the GB segregation transition is amplified if its structure can respond to chemical variation. Additionally, the coupling between GB structural and segregation evolution was found to enable co-existence of the spinodally formed low- and high-Mn phases within the GB. In the light of atomistic simulations, we expand on investigating the correlation between the parameters that characterise the GB density map with GB properties.
T2 - TMS 2023
CY - San Diego, California, USA
DA - 19.03.2023
KW - Grain boundary engineering
KW - Density-based phase-field modelling
KW - Microstructure design
PY - 2023
AN - OPUS4-57970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hickel, Tilmann
A1 - Divinski, S.
A1 - Starikov, S.
A1 - Soisson, F.
A1 - Mény, C.
A1 - Hegde, O.
A1 - Gerlitz, M.
A1 - Magnifouet, G.
A1 - Schneider, A.
A1 - Barreteau, C.
A1 - Mirebeau, I.
A1 - Tran, V.T.
A1 - Förster, G.
A1 - Front, A.
A1 - Egorov, A.
A1 - Wilde, G.
A1 - Amara, H.
A1 - Hammerschmidt, T.
A1 - Mrovec, M.
A1 - Pierron-Bohnes, V.
A1 - Drautz, R.
A1 - Fu, C.
T1 - Magnetism in iron alloys: methodological advances for thermodynamics, defects, and kinetics
N2 - Steels are among the technologically and economically most relevant materials. Key innovations in important sectors of human society such as mobility, energy and safety, are currently based on alloying of Fe with other transition-metal elements such as Mn, Cr, or Co. Due to strong impacts and conceptual challenges related to magnetism, however, the fundamental understanding and the ability to computationally design these steels in high-throughput approaches lags behind other classes of alloys. In this article, we will provide a substantial review of the role of magnetism, magnetic excitations and transformations for alloy thermodynamics, point defects, interfaces and kinetics. This will be achieved by combining insights from different methods: Ab initio simulations have the advantage that the magnetic ground state is intrinsic part of the electronic minimization. Due to the coarsening of the many-electron structures and therewith magnetic interactions, tight-binding methods can handle larger system sizes. Effective interaction models provide the freedom to exploit more sophisticated magnetic interactions. The performance of these methods in terms of magnetic properties of Fe alloys will be evaluated by providing state-of-the-art results for their sensitivity to magnetism. Furthermore, dedicated experiments will be discussed to complete the understanding of magnetic effects in Fe alloys and to validate the modeling strategy.
KW - Magnetic excitations
KW - Defects
KW - Diffusion
KW - Density functional theory
KW - Tight-binding
KW - Effective interaction models
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634530
DO - https://doi.org/10.1515/ijmr-2023-0225
SN - 1862-5282
VL - 60
IS - 99
SP - 1
EP - 14761
PB - Walter de Gruyter GmbH
AN - OPUS4-63453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mai, H. L.
A1 - Cui, X.-Y,
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
A1 - Ringer, S. P.
T1 - A high-throughput ab initio study of elemental segregation and cohesion at ferritic-iron grain boundaries
N2 - Segregation of alloying elements and impurities at grain boundaries (GBs) critically influences material behaviour by affecting cohesion. In this study, we present an ab initio high-throughput evaluation of segregation energies and cohesive effects for all elements up to Z=92 in the periodic table (Z = 1–92, H–U) across the substitutional sites in six model ferritic iron GBs using density functional theory (DFT). From these data, we construct comprehensive elemental maps for solute segregation tendencies and cohesion at GBs, providing guidance for segregation engineering. We systematically assess the cohesive effects of different elements in all segregating positions along multiple fracture paths with a quantum-chemistry bond-order method as well as a modified Rice–Thomson–Wang theory of interfacial cohesion. The effects of segregants on the cohesion of GBs are shown to vary drastically as a function of site character, and hence their induced cohesive effects must
be considered as a thermodynamic average over the spectral energy distribution. Thus, models that overlook these aspects may fail to accurately predict the impacts of varying alloying concentrations, thermal processing conditions, or GB types. The insights presented here, along with our accompanying dataset, are expected to advance our understanding of GB segregation in steels and other materials.
KW - Defects
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638397
DO - https://doi.org/10.1016/j.actamat.2025.121288
SN - 1359-6454
VL - 297
SP - 1
EP - 16
PB - Elsevier Inc.
AN - OPUS4-63839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaiser, Erika
A1 - Fareed, Adnan
A1 - Manzoni, Anna Maria
A1 - Paulisch-Rinke, Melanie C.
A1 - Hsu, Wei-Che
A1 - Yeh, An-Chou
A1 - Murakami, Hideyuki
A1 - Vogel, Florian
A1 - Maaß, Robert
T1 - Pinning-dominated strengthening in high-entropy superalloys
N2 - Hierarchical microstructural design of high-entropy superalloys offers novel strengthening pathways beyond classical superalloys. Here we assess the strength of isolated γ’ precipitates with and without an additional internal γ nanophase. The results show that nano-precipitation within the γ’ phase leads to a marked statistical reduction of the dislocation-nucleation limited yield strength. In concert with disorder-driven chemical weakening of the γ’ phase, these findings indicate that bulk strengthening due to hierarchical microstructural design in high entropy superalloys must primarily be pinning dominated.
KW - High-entropy alloys
KW - Superalloys
KW - Dislocation nucleation
KW - Plasticity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637590
DO - https://doi.org/10.1016/j.scriptamat.2025.116874
SN - 1359-6462
VL - 268
SP - 1
EP - 6
PB - Elsevier Inc.
AN - OPUS4-63759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Han, Seungchang
A1 - Wallis, Theophilus
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - On the preference of liquid-metal embrittlement along high-angle grain-boundaries in galvanized steels
N2 - Focusing on the early stages of liquid-metal embrittlement (LME) of Zinc (Zn) coated advanced high-strength steels, we show that the Zn infiltration path prior to grain-boundary decohesion and therefore cracking distinctly follows high-angle grain boundaries (HAGBs). This selective transport prior to LME-induced microcracking rationalizes the experimentally observed post-mortem cracking along martensitic HAGBs. We discuss the selective Zn transport and GB-weakening in terms of an misorientation-angle dependent atomic density and diffusivity, and its effect on GB-segregation.
KW - Liquid-metal embrittlement
KW - Advanced high-strength steels
KW - Grain boundaries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631103
DO - https://doi.org/10.1016/j.scriptamat.2025.116723
SN - 1359-6462
VL - 265
SP - 1
EP - 5
PB - Elsevier Inc.
AN - OPUS4-63110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roters, F.
A1 - Aslam, A.
A1 - Bai, Y.
A1 - Büschelberger, M.
A1 - Bulert, K.
A1 - Butz, A.
A1 - Hickel, Tilmann
A1 - Jogi, T.
A1 - Klitschke, S.
A1 - Martin, M.
A1 - Meyer, L.-P.
A1 - Morand, L.
A1 - Nahshon, Y.
A1 - Radtke, N.
A1 - Saikia, Ujjal
A1 - Trondl, A.
A1 - Wessel, A.
A1 - Zierep, P.
A1 - Helm, D.
T1 - StahlDigital: Ontology-Based Workflows for the Steel Industry
N2 - The innovative strength of the steel industry is based on the mastery of microstructure–property relationships. Digital workflows can largely contribute to this aim by making the complexity of workflows reproducible and their execution user independent. In this work, the tools and workflows developed in the project StahlDigital as part of the German MaterialDigital initiative are presented and application examples are provided. A steel ontology builds the
foundation for data collection and storage as well as for the semantic description of experimental and simulation data processing workflows. A dataspace powered by the Dataspace Management System (DSMS) digitally represents such workflows and manages data along them in a Findable, Accessible, Interoperable, Reusable manner aiming to derive new knowledge. Experimental data processed via DSMS can be further evaluated and used as input for simulation workflows. The simulations included in such workflows are run by the workflow system pyiron, which has been semantically extended in StahlDigital for this purpose.
KW - Steel
KW - Rolling
KW - Multiscale simulation
KW - Ontology
KW - Workflow
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627187
DO - https://doi.org/10.1002/adem.202402148
SN - 1527-2648
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-62718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, K.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
T1 - Effect of Polycarboxylate Superplasticizer in Ordinary Portland Cement and Sulfate Resistant Cement
N2 - Polycarboxylate superplasticizers (PCE) are the most widely used admixtures in today’s cementitious construction materials. The molecular structure has a decisive influence on the effectiveness of PCE, which also can be tailored to serve in a different cementitious system.
The current study investigates the influence of the backbone charge density of PCE on the rheology, hydration kinetics, and adsorption behavior of ordinary Portland cement (OPC) and sulfate-resistant cement (SRC). The results indicate that regardless of the PCE type, OPC requires a higher amount of PCE to be adsorbed to induce changing of rheological parameters and hydration kinetics. Regardless of the cement type, the PCE with a higher charge density exhibits higher adsorption behavior, corresponding to lower viscosity measurement.
Compared to OPC, SRC is more sensitive to the introduction of both PCEs and has a lower saturation dosage, indicating that SRC generally provides better workability properties regardless of the PCE.
KW - Polycarboxylate superplasticizers (PCE)
KW - Sulfate resistant cement (SRC)
KW - Rheological
KW - Adsorption
KW - Cement hydration
PY - 2023
DO - https://doi.org/10.1061/JMCEE7.MTENG-15033
SN - 0899-1561
VL - 35
IS - 6
SP - 1
EP - 12
PB - ASCE Libary
AN - OPUS4-58244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruschwitz, Sabine
A1 - Völker, Christoph
A1 - Munsch, Sarah Mandy
A1 - Klewe, Tim
A1 - Zia, Ghezal Ahmad Jan
A1 - Schumacher, Katrin
A1 - Yared, Kaleb
A1 - Schmidt, Wolfram
T1 - KI und Robotik im Dienst der Nachhaltigkeit: Beschleunigung innovativer Lösungen im Bausektor
N2 - Der Vortrag beschäftigt sich mit der Implementierung fortschrittlicher Technologien in neue Wertschöpfungsketten im Bausektor, insbesondere im Bereich Recycling, zirkuläres Produktdesign und Lebenszustandsanalyse. Im Zentrum stehen Industrie- und Grundlagenforschungsprojekte an der Schnittstelle zwischen Wissenschaft und praktischer Anwendung.
T2 - DigiCon 2024
CY - Munich, Germany
DA - 21.11.2024
KW - KI
KW - Materialdesign
KW - Recycling
KW - Baumaterial
PY - 2024
AN - OPUS4-61800
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Wolfram
A1 - Kanjee, J.
A1 - Motukwa, G.
A1 - Olonade, K.
A1 - Dodoo, A.
T1 - A snapshot review of future‑oriented standards for cement, admixtures, and concrete: How Africa can spearhead the implementation of green urban construction materials
N2 - The existing cement and concrete standards are not capable of making full use of the current technology capacity due to strong focus on conventional concrete and thus they are not fit for the current and future challenges of construction industry. The paper highlights shortcomings with regard to the implementation of the existing standards. It can be seen that future-oriented standards are generally required to contribute to a lower-carbon footprint of the industry. These changes are significantly more relevant in sub-Saharan Africa, due to the rapidly increasing urbanisation challenge and the enormous potentials to develop lower-carbon technologies than elsewhere in the world.
KW - Future‑oriented standards
KW - Green urban construction
KW - Cement
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582563
DO - https://doi.org/10.1557/s43580-023-00563-9
SN - 2731-5894
VL - 4
IS - 8
SP - 557
EP - 565
PB - Springer International Publishing
CY - Springer Nature Switzerland, Cham
AN - OPUS4-58256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z.
A1 - Becker, S.
A1 - Leinitz, Sarah
A1 - Schmidt, Wolfram
A1 - von Klitzing, R.
A1 - Stephan, D.
T1 - Interaction of Different Charged Polymers with Potassium Ions and Their Effect on the Yield Stress of Highly Concentrated Glass Bead Suspensions
N2 - The interaction of different charged polymers, namely anionic polycarboxylate
superplasticizer (PCE) and neutral polyethylene glycol (PEG) with potassium ions, and their effect on the yield stress of highly concentrated glass bead suspension (GBS), were studied under different concentrations of potassium ions ([K+]). It was found that, compared to the neutral PEG, the negatively charged PCE can be adsorbed on glass beads (GB), and then decreases the yield stress of GBS. The increasing concentration of free polymer in the interstitial liquid phase with the increased polymer dosage leads to the higher yield stress of GBS, which may be caused by the higher Depletion force. In addition, this effect is also related to the charge density of the polymer and the [K+] in the solution. Along with the increase in [K+], the yield stress of GBS increases significantly with the addition of PCE, but this cannot be observed with PEG, which indicates that potassium ions can interact with negatively charged PCE instead of the neutral PEG. At last, the interparticle Forces between two single GB with adsorbed PCE in solutions containing [K+] and PCE were measured by colloidal probe atomic force microscopy to better understand the interaction of the charged polymer with counterions.
KW - Yield stress
KW - Free polymer
KW - Charge density
KW - Depletion force
KW - Potassium ions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506015
DO - https://doi.org/10.3390/ma13071490
SN - 1996-1944
VL - 13
IS - 7
SP - 1490, 1
EP - 1490, 16
PB - MDPI
AN - OPUS4-50601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, K.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
T1 - Chemical and thixotropic contribution to the structural build-up of cementitious materials
N2 - The structural build-up of fresh cement paste is often considered as a purely thixotropic phenomenon in literature even though cementitious materials undergo a non-reversible hydration process that can have an influence on the structuration process. In the current paper a method is proposed to validate the impact of the non-reversible structural build-up. It is shown that fresh cement paste samples lose their structural gain almost completely due to thixotropy while the structural build-up due to hydration can be observed but occurs in a significantly lower order of magnitude over the course of the first hours of hydration. In addition, it is shown, that the chemical component of the structural build-up accelerates with the onset of the acceleration period of hydration, while its contribution in the entire structural build-up remains constant.
KW - Thixotropy
KW - Structural build-up
KW - Penetration test
KW - Rheological properties
PY - 2022
DO - https://doi.org/10.1016/j.conbuildmat.2022.128307
SN - 0950-0618
VL - 345
IS - 128307
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-58248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pott, U.
A1 - Crasselt, Claudia
A1 - Fobbe, N.
A1 - Haist, M.
A1 - Heinemann, M.
A1 - Hellmann, S.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Lei, L.
A1 - Li, R.
A1 - Link, J.
A1 - Lowke, D.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Nicia, D.
A1 - Plank, J.
A1 - Reißig, S.
A1 - Schäfer, T.
A1 - Schilde, C.
A1 - Schmidt, Wolfram
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Strybny, B.
A1 - Ukrainczyk, N.
A1 - Wolf, J.
A1 - Xiao, P.
A1 - Stephan, D.
T1 - Characterization data of reference materials used for phase II of the priority program DFG SPP 2005 “Opus Fluidum Futurum –Rheology of reactive, multiscale, multiphase construction materials”
N2 - A thorough characterization of base materials is the prereq- uisite for further research. In this paper, the characterization data of the reference materials (CEM I 42.5 R, limestone pow- der, calcined clay and a mixture of these three components) used in the second funding phase of the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented under the aspects of chemical and min- eralogical composition as well as physical and chemical properties. The data were collected based on tests performed by up to eleven research groups involved in this cooperative program.
KW - Portland cement
KW - Limestone powder
KW - Calcined clay
KW - Sustainable cement
KW - DFG SPP 2005
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569913
DO - https://doi.org/10.1016/j.dib.2023.108902
VL - 47
SP - 1
EP - 19
PB - Elsevier
AN - OPUS4-56991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhang, K.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
T1 - Thixotropic and chemical structural build-up of cement pastes with superplasticizer under different storage conditions
N2 - Synopsis: The paper presents the results of a study on the influence of agitation on the structural build-up of fresh cement pastes using a penetration test. It first presents results about the influence of the penetrating shape’s geometry on the influence on the cement paste specimen. Then, results are shown for the load-deflection curves depending upon time and agitation before testing. Based on the observation of the force required to penetrate the sample, conclusions on the structural build-up can be made. The observations were made over the course of time with samples that were left at rest and partly agitated before testing at different time steps. The setup allows to identify the contribution of the chemical reaction to the structural build-up process. The presence of superplasticizer obviously reduces the load that cement paste can withstand, while the loss of thixotropy is found notably lower than that of neat cement pates
T2 - 13th International Conference on Superplasticizers and Other Chemical Admixtures in Concrete
CY - Milan, Italy
DA - 10.07.2022
KW - Thixotropy
KW - Superplasticizer
KW - Structural build-up
KW - Texture analyzer
KW - Penetration test
PY - 2022
DO - https://doi.org/10.14359/51736058
VL - 354
SP - 13
EP - 24
PB - ACI Special Publications
AN - OPUS4-58324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
A1 - Zhang, H.
A1 - Diesendruck, Ch. E.
T1 - The effect of the charge density of a comb polyphosphate superplasticizer on the structural build-up of cement paste
N2 - Synopsis: Lately, there has been rising attention to superplasticizers (SP) based on polyphosphate esters. However, the influence of the molecular structure of the polyphosphate polymers on time-dependent properties such as structural build-up has not been examined yet intensively. To investigate this effect, three comb polyphosphate superplasticizers with different charge densities were synthesised by free radical polymerisation. Our findings indicate that SP with the lowest and medium charge densities extend the induction period more strongly than the SP with the highest charge density. The reduction of the structural build-up rate is linearly dependent on the dosage and concentration of the functional group of polyphosphate SP in the cementitious system. This study proposes a mathematical equation expressing the relationship between the structural build-up rate during the induction period and the molecular structure of the polyphosphate SP.
T2 - 13th International Conference on Superplasticizers and Other Chemical Admixtures in Concrete
CY - Milan, Italien
DA - 10.07.2022
KW - Admixture
KW - Superplasticizer
KW - Polyphosphate
KW - Structural build-up
PY - 2022
DO - https://doi.org/10.14359/51736079
VL - 354
SP - 255
EP - 262
PB - ACI Special Publications
AN - OPUS4-58321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Carvello, J. M. F.
A1 - Schmidt, Wolfram
A1 - Kühne, Hans-Carsten
A1 - Fiorotti Peixoto, R. A.
T1 - Influence of high-charge and low-charge PCE-based superplasticizers on Portland cement pastes containing particle-size designed recycled mineral admixtures
N2 - Design : and use of engineered recycled mineral admixtures obtained from industrial and mineral waste are promising strategies to increase the range of materials suitable for use in cement-based composites. In this work, Portland cement-blended pastes containing mineral admixtures designed for improving particle packing were evaluated in the presence of low- and high-charge polycarboxylate-based superplasticizers. The powders were obtained from basic oxygen furnace slag, iron ore tailings, quartz mining tailings, and quartzite mining tailings. The zeta-potentials of the particles were obtained via electrophoretic mobility. The flow properties were evaluated by rheological tests performed in a Couette type rheometer. The hydration kinetics was evaluated by isothermal calorimetry and an adapted method based on the Vicat needle test. The high-charge PCE and the finer mineral admixtures produced more stable blends. Coarser mineral admixtures led to increased flowability and delayed hydration compared to finer ones. Steel slag powders presented the most significant plasticizer effects, but also the largest setting delays and segregation tendency. Quartz-rich superfines reduced the setting delays caused by the superplasticizers. In summary, both superplasticizers were effective in improving flow properties, but the high-charge PCE was effective in preventing segregation in pastes containing mineral admixtures coarser and heavier than cement.
KW - Engineered recycled mineral admixtures
KW - Rheology
KW - PCE-Based superplasticizer
KW - Steel slag
KW - Mining tailing
PY - 2020
DO - https://doi.org/10.1016/j.jobe.2020.101515
VL - 32
SP - 1
EP - 16
PB - Elsevier
AN - OPUS4-58395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Robens-Radermacher, Annika
T1 - Temperature dependent modelling approach for early age behavior of printable mortars
N2 - For extrusion-based 3D concrete printing, the early age mechanical behavior is influenced by various time dependent phenomena: structural build-up, plasticity as well as viscosity. The structural build-up is governing the stability and early-age strength development of the fresh printable cementitious materials and with that influencing the printability, buildability, and open time of the printing process. Generally, it is influenced by a number of factors, i.e. composition of the printable material, printing regime, and ambient conditions (temperature, humidity, etc.). There are several approaches to model the structural build-up of cementitious materials. All models are based on a time-dependent internal structural parameter describing the flocculation state, which is assumed to be zero after mixing and increases with time. The approaches differ in the definition of the time dependency (linear, exponential, bi-linear). Usually, the parameters are defined for a specific material composition without considering the influence of ambient conditions.
In this contribution, the bi-linear structural build-up model [Kruger et al., Construction and Building Materials 224, 2019] is extended by the temperature influence. Temperature changes will occur in real life printing processes due to changing ambient conditions (summer, winter, day, night) as well as the printing process (pressure changes etc.) and have a significant impact on the structural build-up process: an increase of the temperature leads to a faster dissolution of cement phases, accelerates hydration and boosts the Brownian motion. For that reason, the model parameters are simulated as temperature dependent using an Arrhenius function. Furthermore, the proposed extended model is calibrated based on measurement data using Bayesian inference. A very good agreement of the predicted model data with the measured control data was reached. Additionally, the structural build-up model is integrated into a viscoelastic and elastoplastic mechanical model, simulating the whole mechanical behavior during layer deposition.
T2 - Eighth International Symposium on Life-Cycle Civil Engineering (IALCCE 2023)
CY - Milan, Italy
DA - 03.07.2023
KW - 3D concrete printing
KW - Material characterization
KW - Structural build-up
KW - Thixotropy
KW - Model calibration
PY - 2023
AN - OPUS4-58218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezhov, Alexander
A1 - Robens-Radermacher, Annika
T1 - Temperature Impact on the Structural Build-Up of Cementitious Materials - Experimental and Modelling Study
N2 - With increasing focus on industrialized processing, investigating, understanding, and modelling the structural build-up of cementitious materials becomes more important. The structural build-up governs the key property of fresh printable materials -- buildability -- and it influences the mechanical properties after the deposition. The structural build-up rate can be adjusted by optimization of the mixture composition and the use of concrete admixtures. Additionally, it is known, that the environmental conditions, i.e. humidity and temperature have a significant impact on the kinetic of cement hydration and the resulting hardened properties, such as shrinkage, cracking resistance etc. In this study, small amplitude oscillatory shear (SAOS) tests are applied to examine the structural build-up rate of cement paste subject to different temperatures under controlled humidity. The results indicate significant influences of the ambient temperature on the intensity of the re-flocculation (Rthix) rate, while the structuration rate (Athix) is almost not affected. A bi-linear thixotropy model extended by temperature dependent parameters coupled with a linear viscoelastic material model is proposed to simulate the mechanical behaviour considering the structural build-up during the SAOS test.
T2 - Third RILEM International Conference on Concrete and Digital Fabrication (Digital Concrete 2022)
CY - Loughborough, UK
DA - 27.06.2022
KW - Structural build-up
KW - Rheological properties
KW - Modelling
PY - 2022
AN - OPUS4-55581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lorenzoni, Renata
T1 - Microstructure of biochar-based concrete: MIP, gas sorption, NMR, and μ-CT analysis
N2 - The global demand for concrete is growing, and with it, its carbon footprint. Current literature proposes biochar, a product of pyrolysis, as a possible car-bon sink to reduce the carbon footprint of concrete. This work investigates the microstructure of Portland cement pastes with 0%, 5%, and 25% of the cement replaced with wood biochar, since this should influence its macro-scopic mechanical properties. MIP, gas sorption, NMR, and µ-CT were used to analyze the pore space of the three materials. The combination of these methods, each with different resolution, enables a multi-scale investigation of biochar impact on the microstructure of cement pastes. NMR confirmed that biochar can absorb moisture and, thus, reduces the effective water-to-cement ratio. MIP and gas sorption results show 0% and 5% volume re-placement have similar gel pore structure. The results from µ-CT investiga-tions suggest that biochar may reduce the formation of larger pores. The in-clusion of non-reactive porous particles such as biochar increase the porosity of the material and should act as a weakness in terms of mechanical proper-ties. Overall, this study highlights the need to carefully tailor replacement rates to control the impact of biochar on the microstructure concrete mixtures and sees a strong need for further studies on mechanical properties.
T2 - 5th International Conference on Bio-Based Building Materials
CY - Vienna, Austria
DA - 20.06.2023
KW - Biochar
KW - Microstructure
KW - Cement
KW - Porosity
PY - 2023
AN - OPUS4-57948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
A1 - Olonade, K. A.
A1 - Mbugua, R. N.
A1 - Lenz, F. J.
A1 - Tchetgnia Ngassam, I.
T1 - Bio-Based Rheology Modifiers for High Performance Concrete – Possible Modes of Actions and Case Study for Cassava Starch in West Africa
N2 - Polymers that help tailoring rheological properties during the casting process have become inevitable constituents for all kinds of high-performance concrete technologies. Due to lacking industries, these typically crude-oil based admixtures are not readily available in many parts of the world, which limits the implementation of more sustainable high-performance construction technologies in these regions. Alternative polymers, which often demand for less processing, can be derived from local plant-based resources. The paper provides experimental data of flow tests of cement pastes with polysaccharides from Triumfetta pendrata A. Rich, acacia gum and cassava without and in the presence of polycarboxylate ether superplasticizer. The flow tests are amended by observations of the zeta potentials and the hydrodynamic diameters in the presence of and without calcium ions in the dispersion medium. The results show that in the presence of and without calcium ions all polysaccharides provide negative zeta potentials, yet, they affect flowability and thixotropy in different ways. Cassava starch, acacia gum, and the gum of Triumfetta pendrata A. Rich qualified well for robustness improvement, strong stiffening, and additive manufacturing, respectively. The reason for the different effects can be found in their average sizes and size distribution. Due to the promising results, a flow chart for local value chains is derived on the example of yet unused cassava wastes, which can be converted in parallel.
T2 - 3rd International Conference on the Application of Superabsorbent Polymers
CY - Skukuza, South Africa
KW - Admixtures
KW - Polysaccharides
KW - Rheology
KW - Thixotropy
KW - Concrete
PY - 2020
SN - 978-3-030-33341-6
SN - 978-3-030-33342-3
DO - https://doi.org/10.1007/978-3-030-33342-3_17
SP - 158
EP - 166
PB - Springer
AN - OPUS4-58404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezhov, Alexander
A1 - Robens-Radermacher, Annika
ED - Mezhov, Alexander
ED - Robens-Radermacher, Annika
ED - Zhang, Kun
ED - Kühne, Hans-Carsten
ED - Unger, Jörg F.
ED - Schmidt, Wolfram
T1 - Temperature Impact on the Structural Build-Up of Cementitious Materials - Experimental and Modelling Study
N2 - With increasing focus on industrialized processing, investigating, understanding, and modelling the structural build-up of cementitious materials becomes more important. The structural build-up governs the key property of fresh printable materials -- buildability -- and it influences the mechanical properties after the deposition. The structural build-up rate can be adjusted by optimization of the mixture composition and the use of concrete admixtures. Additionally, it is known, that the environmental conditions, i.e. humidity and temperature have a significant impact on the kinetic of cement hydration and the resulting hardened properties, such as shrinkage, cracking resistance etc. In this study, small amplitude oscillatory shear (SAOS) tests are applied to examine the structural build-up rate of cement paste subject to different temperatures under controlled humidity. The results indicate significant influences of the ambient temperature on the intensity of the re-flocculation (Rthix) rate, while the structuration rate (Athix) is almost not affected. A bi-linear thixotropy model extended by temperature dependent parameters coupled with a linear viscoelastic material model is proposed to simulate the mechanical behaviour considering the structural build-up during the SAOS test
T2 - Third RILEM International Conference on Concrete and Digital Fabrication (Digital Concrete 2022)
CY - Loughborough, UK
DA - 27.06.2022
KW - Structural build-up
KW - Rheological properties
KW - Modelling
PY - 2022
SN - 978-3-031-06116-5
DO - https://doi.org/10.1007/978-3-031-06116-5_49
VL - 37
SP - 330
EP - 336
PB - Springer International Publishing
CY - Cham
AN - OPUS4-55580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Robens-Radermacher, Annika
A1 - Unger, Jörg F.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
ED - Biondini, F.
ED - Frangopo, D. M.
T1 - Temperature dependent modelling approach for early age behavior of printable mortars
N2 - Structural build-up describes the stability and early-age strength development of fresh mortar used in 3D printing. lt is influenced by several factors, i.e. the composition of the print able material, the printing regime, and the ambient conditions. The existing modelling approaches for structural build-up usually define the model parameters for a specific material composition with out considering the influence of the ambient conditions. The goal of this contribution is to explicitly include the temperature dependency in the modelling approach. Temperature changes have signifi cant impact on the structural build-up process: an increase of the temperature leads to a faster dissol ution of cement phases and accelerates hydration. The proposed extended model includes temperature dependency using the Arrhenius theory. The new model parameters are successfully calibrated based on Viskomat measurement data using Bayesian inference. Furthermore, a higher impact of the temperature in the re-flocculation as in the structuration stage is observed.
T2 - The Eighth International Symposium on Life-Cycle Civil Engineering (IALCCE 2023)
CY - Milano, Italien
DA - 02.07.2023
KW - 3D concrete printing
KW - Material characterization
KW - Structural build-up
KW - Thixotropy
KW - Model calibration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582175
SN - 978-1-003-32302-0
DO - https://doi.org/10.1201/9781003323020-146
SN - 978-1-003-32302-0
VL - 1st Edition
SP - 1193
EP - 1200
PB - CRC Press
AN - OPUS4-58217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ramirez Caro, Alejandra
A1 - Pauli, Jutta
A1 - Mota, Berta
A1 - Simon, Sebastian
A1 - Schmidt, Wolfram
A1 - Resch-Genger, Ute
T1 - C3A passivation with gypsum and hemihydrate monitored by optical spectroscopy
N2 - Tricalcium aluminate (C3A) is found with less than 10% wt. of the total composition; however, during hydration, C3A plays an important role in the early hydration of cement in the presence of gypsum as a set retarder.
The aim of this investigation is to assess the suitability of optical spectroscopy and a dye-based optical probe to monitor early hydration of C3A in the presence of gypsum and hemihydrate. Optical evaluation was performed using steady-state fluorescence and diffuses reflectance spectroscopy (UV-VisDR). Phase characterization during hydration was done with in-situ X-ray diffraction. UV-VisDR with a cyanine dye probe was used to monitor the formation of metastable phases and was employed together with fluorescence spectroscopy, to follow the Aggregation and disaggregation of the dye during hydration. In conclusion, for the first time, a cyanine dye was identified as a feasible and stable probe to monitor C3A hydration changes in the presence of calcium sulfate.
KW - Dye
KW - Photoluminescence
KW - Fluorescence
KW - Reflection spectroscopy
KW - Cement
KW - Hydration
KW - Method development
PY - 2020
DO - https://doi.org/10.1016/j.cemconres.2020.106082
VL - 133
SP - 106082
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-50952
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Franco de Carvalho, J. M.
A1 - Defàveri, K-
A1 - Castro Mendes, J.
A1 - Schmidt, Wolfram
A1 - Kühne, Hans-Carsten
A1 - Fiorotti Peixoto, R. A.
T1 - Influence of particle size-designed recycled mineral admixtures on the properties of cement-based composites
N2 - In this work, engineered recycled mineral admixtures were obtained from four different industrial residues: basic oxygen furnace slag, iron ore tailings, quartz mining tailings and quartzite mining tailings.
The grinding performance was evaluated in two different programs and the characterization included chemical and mineralogical composition, particle morphology, and physical properties. Performance evaluations were carried out in blended pastes and mortars, including flow properties, hydration kinetics, soundness, pozzolanic activity, and compressive strength. Coarser-than-cement admixtures allowed better flow performance, greater dimensional stability and more economical production, while finer-thancementn admixtures improved mechanical performance by both filler effect and cementing activity.
KW - Engineered recycled mineral admixtures
KW - Rheology
KW - Hydration kinetics
KW - Basic oxygen furnace slag
KW - Iron ore tailings
KW - Mining tailings
PY - 2021
DO - https://doi.org/10.1016/j.conbuildmat.2020.121640
SN - 0950-0618
VL - 272
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-58255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haist, M.
A1 - Link, J.
A1 - Nicia, D.
A1 - Leinitz, Sarah
A1 - Baumert, C.
A1 - von Bronk, T.
A1 - Cotardo, D.
A1 - Eslami Pirharati, M.
A1 - Fataei, S.
A1 - Garrecht, H.
A1 - Gehlen, C.
A1 - Hauschildt, I.
A1 - Ivanova, I.
A1 - Jesinghausen, S.
A1 - Klein, C.
A1 - Krauss, H.-W.
A1 - Lohaus, L.
A1 - Lowke, D.
A1 - Mazanec, O.
A1 - Pawelczyk, S.
A1 - Pott, U.
A1 - Radebe, N. W.
A1 - Riedmiller, J. J.
A1 - Schmid, H.-J.
A1 - Schmidt, Wolfram
A1 - Secrieru, E.
A1 - Stephan, D.
A1 - Thiedeitz, M.
A1 - Wilhelm, M.
A1 - Mechtcherine, V.
T1 - Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries
N2 - This paper presents the results of an interlaboratory study of the rheological properties of cement paste and ultrasound gel as reference substance. The goal was to quantify the comparability and reproducibility of measurements of the Bingham parameters yield stress and plastic viscosity when measured on one specific paste composition and one particular ultrasound gel in different laboratories using different rheometers and measurement geometries.
The procedures for both in preparing the cement paste and carrying out the rheological measurements on cement paste and ultrasound gel were carefully defined for all of the study’s participants. Different conversion schemes for comparing the results obtained with the different measurement setups are presented here and critically discussed. The procedure proposed in this paper ensured a reasonable comparability of the results with a coefficient of variation for the yield stress of 27% and for the plastic viscosity of 24%, despite the individual measurement series’ having been performed in different labs with different rheometers and measurement geometries.
KW - Rheometry
KW - Rheology
KW - Interlaboratory test
KW - Test setup
KW - Testing procedure
KW - Cement paste
KW - Ultrasound gel
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511220
DO - https://doi.org/10.1617/s11527-020-01477-w
SN - 1871-6873
VL - 53
IS - 4
SP - 92
PB - Rilem
AN - OPUS4-51122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scholtz, Lena
T1 - Luminescent, Semiconductor Nanoparticle-Loadedpolymer Microbeads–Comparingparticlearchitectures
N2 - Luminescent polymer microparticles (PMPs) are applied in various (bio)analytical and diagnostic processes.[1] The staining of these beads is important for the realization of optically distinguishable barcodes that can be read out, e.g., by a flow cytometer or fluorescence microscope. Typically, luminescent semiconductor nanoparticles (NPs) absorb in a broad wavelength range and show narrow emission bands, which enables simultaneous excitation of differently colored luminophores and facilitates a spectral discrimination.[1] This makes them ideal candidates for this purpose and encouraged us to explore and develop a simple, effective approach to luminescent semiconductor NP encoding of polystyrene PMPs and identify suitable synthesis conditions.[2]
Until now, mainly semiconductor quantum dots (QDs) have been used for the synthesis of luminescent PMPs, although NPs with different shapes could introduce beneficial new features. Aiming for the application of our developed procedure to non-spherical NPs, we systematically investigated the luminescence properties of the resulting NP-stained beads using fluorescence and integrating sphere spectroscopy as well as fluorescence and electron microscopy. These studies showed that the suitability of semiconductor NPs for the synthesis of luminescent PMPs depends not only on their shape, but also heavily on their surface chemistry.[3] The successful incorporation of nonspherical NPs opens the path to include even more NPs, and the results can help to deduce future applications for the beads which best suit their specific properties.
T2 - E-MRS Fall Meeting 2025
CY - Warsaw, Poland
DA - 15.09.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum dot
KW - Quantum rod
KW - Platelet
KW - Quantum yield
KW - Polymer particle
KW - Encoding
KW - Surface chemistry
KW - Mechanism
KW - Characterization
KW - Lifetime
KW - Barcode
KW - Polymerization
KW - Method
PY - 2025
AN - OPUS4-64242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - Ag₂S nanocrystals as next-generation, heavy-metal free SWIR emitter for biomedical imaging and sensing applications
N2 - There is a growing interest in the exploitation of the short-wave infrared (SWIR), which refers to the wavelength band of light between 900 nm and 2500 nm. Luminophores that emit in the SWIR are used in various areas of telecommunications, photovoltaics, security systems (night vision), and in biomedicine. In particular for biomedical applications, the SWIR range is highly promising because light scattering, absorption, and autofluorescence of tissue and biological compounds are strongly reduced compared to the visible (400–700 nm) and NIR (~700–900 nm). The benefits of SWIR-emissive QDs have been demonstrated for a variety of applications, such as in thermal sensing, as photoelectrochemical biosensor, in in vivo vascular imaging, and for fluorescence-guided surgery.
Full exploitation of SWIR photoluminescence (PL) imaging and sensing is currently hampered by i.) a lack of suitable advanced nanomaterials with a high PL quantum yield (PL QY) and a high brightness, that can be used safely in vivo and ii.) a lack of quantitative and reliable data on the optical properties of many SWIR emitters. Promising nanomaterials for the SWIR are heavy metal-free Ag2S quantum dots (QDs).
Aiming for the development of SWIR advanced nanomaterials with optimum performance, we have dived deeper into the photophysical processes occurring in these nanomaterials, thereby exploring in depth how the environment such as temperature, surface ligand composition, and the incorporation of transition metals influence the optical properties Ag2S QDs. We observed a strong enhancement of the SWIR emission of upon addition of metal ions such as Zn2+, yielding PL quantum yields of about 10% and thus making them highly suitable for non-invasive deep imaging of vascular networks and 3D fluid flow mapping.
T2 - Shining a light on biomedical and energy applications (Shift)
CY - Tenerife, Spain
DA - 13.10.2025
KW - Quantum dots
KW - Short-wave infrared
KW - SWIR
KW - Spectroscopy
KW - Photoluminescence
KW - Quantum yield
PY - 2025
AN - OPUS4-64673
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
T1 - Maßgeschneiderte künstliche Bewitterungstests zur Untersuchung der alterungsbedingten Freisetzung von Produkten in die Umwelt
N2 - Genormte künstliche Bewitterungstests sind häufig nicht spezifisch für die Anwendungssituation oder das Material. Das macht die Entwicklung spezifischer Tests erforderlich. Für deren Entwicklung müssen Maximalparameter der Anwendungssituation bekannt sein, womit dann der künstliche Test formuliert wird und dessen Bedingungen werden dann solange optimiert, bis die Korrelation der Effekte von natürlichem und künstlichem Test ausreichend ist.
Für Untersuchungen der Freisetzung kann der verbleibende Rest in der Probe und/oder die freigesetzte Menge in Luft, Boden, Wasser bestimmt werden.
Im ersten Beispiel der Witterungswirkung wurde die Freisetzung von Kohlenstoff-Nanoröhrchen (CNT) aus Polymer-Kompositen untersucht (unter Verwendung von empfindlich-nachweisbarer radioaktiver 14C-Markierung für einzelne CNT-Partikel), in einem zweiten die Freisetzung von anorganischen und organischen Bestandteilen aus elastomeren Bestandteilen von Sportböden (Bahnen und Kunstrasen) in Wasser.
T2 - SKZ-Tagung: Bewitterung van Kunststoffen
CY - Würzburg, Germany
DA - 06.07.2022
KW - Künstliche Bewitterung
KW - UV
KW - Degradation
KW - Freisetzung
KW - CNT
KW - Carbo-Nanotubes
KW - Composite
KW - Nano-Partikel
KW - 14C-Markierung
KW - Sportböden
KW - Kunstrasen
KW - Grundwasser
PY - 2022
AN - OPUS4-55219
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schraut, Katharina
T1 - Reductive treatment of steel making slags to produce a hydraulic binder and crude iron
N2 - Steelmaking slags are a by-product of steel production, that are currently used primarily in road construction, earthwork, and hydraulic engineering. In this use, the iron bound in the steelmaking slags (< 30 wt.%) is lost.
Recovery of iron from steelmaking slags is possible by thermochemical reductive treatment. The reductive treatment of liquid steelmaking slags causes iron oxides to be reduced to metallic iron, which separates from the mineral phase due to its higher density. The chemical composition of the mineral phase is thus adapted to that of the Portland cement clinker and the mineral alite, the most important component of Portland cement, is formed. This way, crude iron can be recovered, and at the same time a hydraulic binder can be produced.
This process, however, is uneconomical due to the high temperatures required (~1800 °C). In the current project, the process is to be adapted so that the reduction of liquid steelmaking slag can be carried out at ~1600 °C. The chemical composition is to be modified in such a way that the melting temperature of the slags as well as their viscosity are in a technically suitable range and still a product with good cementitious properties is obtained.
T2 - LithiumDays
CY - Online meeting
DA - 06.12.2021
KW - BOFS
KW - Portland Cement
KW - Hydraulic reactivity
PY - 2021
AN - OPUS4-56081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andresen, Elina
A1 - Islam, Fahima
A1 - Prinz, Carsten
A1 - Gehrmann, P.
A1 - Licha, K.
A1 - Roik, Janina
A1 - Recknagel, Sebastian
A1 - Resch-Genger, Ute
T1 - Assessing the reproducibility and up‑scaling of the synthesis of Er,Yb‑doped NaYF4‑based upconverting nanoparticles and control of size, morphology, and optical properties
N2 - Lanthanide-based, spectrally shifting, and multi-color luminescent upconverting nanoparticles (UCNPs) have received much attention in the last decades because of their applicability as reporter for bioimaging, super-resolution microscopy, and sensing as well as barcoding and anti-counterfeiting tags. A prerequisite for the broad application of UCNPs in areas such as sensing and encoding are simple, robust, and easily upscalable synthesis protocols that yield large quantities of UCNPs with sizes of 20 nm or more with precisely controlled and tunable physicochemical properties from lowcost reagents with a high reproducibility. In this context, we studied the reproducibility, robustness, and upscalability of the synthesis of β-NaYF4:Yb, Er UCNPs via thermal decomposition. Reaction parameters included solvent, precursor chemical compositions, ratio, and concentration. The resulting UCNPs were then examined regarding their application-relevant physicochemical properties such as size, size distribution, morphology, crystal phase, chemical composition, and photoluminescence.
Based on these screening studies, we propose a small volume and high-concentration synthesis approach that can provide UCNPs with different, yet controlled size, an excellent phase purity and tunable morphology in batch sizes of up to at least 5 g which are well suited for the fabrication of sensors, printable barcodes or authentication and recycling tags.
KW - Photoluminescence
KW - Nano
KW - Nanomaterial
KW - Synthesis
KW - Reproducibility
KW - Upconversion nanoparticle
KW - Lanthanide
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570170
DO - https://doi.org/10.1038/s41598-023-28875-8
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 13
AN - OPUS4-57017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Halisch, M.
A1 - Dlugosch, R.
A1 - Prinz, Carsten
T1 - Toward a better understanding of low-frequency electrical relaxation - An enhanced pore space characterization
N2 - Relaxation phenomena observed in the electrical low-frequency range (approximately 1 mHz-10 kHz) of natural porous media like sandstones is often assumed to be directly related to the dominant (modal) pore throat sizes measured, for instance, with mercury intrusion porosimetry. Attempts to establish a universally valid relationship between pore size and peak Spectral Induced Polarization (SIP) relaxation time have failed, considering sandstones from very different origins and featuring great variations in textural and chemical compositions as well as in geometrical pore space properties. In addition working with characteristic relaxation times determined in Cole-Cole or Debye decomposition fits to build the relationship have not been successful. In particular, samples with narrow pore throats are often characterized by long SIP relaxation times corresponding to long “characteristic length scales” in these media, assuming that the diffusion coefficients along the electrical double layer were constant. Based on these observations, three different types of SIP relaxation can be distinguished. We present a new way of assessing complex pore spaces of very different sandstones in a multi-methodical approach to combine the benefits of mercury intrusion porosimetry, micro-computed tomography, and nuclear magnetic resonance. In this way, we achieve much deeper insight into the pore space due to the different resolutions and sensitivities of the applied methods to both pore constrictions (throats) and wide pores (pore bodies). We experimentally quantify pore aspect ratios and volume distributions within the two pore regions. We clearly observe systematic differences between three SIP relaxation types identified previously and can attribute the SIP peak relaxation times to measured characteristic length scales within our materials. We highlight selected results for a total of nine sandstones. It seems that SIP relaxation behavior depends on the size difference of the narrow pore throats to the wide pore bodies, which increases from SIP Type 1 to Type 3.
KW - µ-CT
KW - Spectral induced polarization
KW - Nuclear magnetic resonance
KW - Pore space
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509763
DO - https://doi.org/10.1190/GEO2019-0074.1
SN - 0016-8033
VL - 85
IS - 4
SP - MR257
EP - MR270
PB - Society of Exploration Geophysicists
AN - OPUS4-50976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Redda, Zinnabu T.
A1 - Brennecke, Daniel
A1 - Prinz, Carsten
A1 - Yimam, Abubeker
A1 - Barz, Mirko
A1 - Kadow, Steffen
A1 - Laß-Seyoum, Asnakech
T1 - Synthesis and characterization of AlPO4-18 supported mesoporous and crystalline β-Mo2C, Ni3C, and WC nanoparticles
N2 - Developing high-efficiency, high-stability, and low-cost deoxygenation and hydrocracking catalysts could be considered one of the most significant breakthroughs in catalytic hydroprocessing. The present study utilized aluminophosphate (AlPO4-18), a zeolite-like molecular sieve, as catalyst support for producing carbon-coated β-Mo2C, Ni3C, and WC nanoparticles. The synthesis used an incipient wetness impregnation followed by a temperature-programmed reduction-carburization approach which involved cracking a hydrocarbon gas, propane, in a hydrogen environment. The synthesis parameters were a 1:7 propane/hydrogen reductive-carburizing gas stream, 15 wt.% metal loading, an 800 °C carburization temperature ramped-up at a heating rate of 10 °C min−1, a 2-h holding time, and a 1-h holding time in hydrogen. The synthesized catalysts were characterized using thermogravimetry mass spectroscopy/temperature-programmed oxidation (TPO TG-MS), nitrogen physisorption at 77 K, X-ray diffraction (XRD), and transmission electron microscopy/energy-dispersive X-ray spectroscopy (TEM EDS). TPO TG-MS, nitrogen physisorption, TEM, and XRD characterization results proved that atomic carbon was successfully incorporated into the lattice interstitials, resulting in thermally stable, well-dispersed, crystalline and mesoporous β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18 nanoparticles. XRD analysis showed structural evolution during reduction-carburization, with average crystallite sizes of metal-containing particles of 8.2–9.22, 6.64–8.50, and 6.03–7.56 nm for β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18, respectively. These values did not significantly deviate from high-resolution TEM analysis. The surface areas of the nanoparticles were categorized in decreasing order as WC/AlPO4-18 > Ni3C/AlPO4-18 > β-Mo2C/AlPO4-18, with values of 193.79, 169.05, and 66.57 m2 g−1, respectively. In conclusion, these carbon-coated metal carbide nanoparticles with excellent thermal, structural, microscopic, and textural properties can be viable alternatives to noble metal catalysts for producing bio-jet fuel using the hydroprocessing pathway.
KW - Catalyst synthesis
KW - Temperature-programmed reduction-carburization
KW - Catalyst characterization
KW - BET surface area
KW - Nanoparticle
KW - Transition metal carbide catalyst
KW - TEM
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608182
DO - https://doi.org/10.1007/s10562-024-04791-y
SN - 1011-372X
SN - 1572-879X
VL - 154
SP - 5969
EP - 5988
PB - Springer Science and Business Media
CY - Dordrecht
AN - OPUS4-60818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoogendoorn, Levi
A1 - Huertas, Mauricio
A1 - Nitz, Phillip
A1 - Qi, Naiyu
A1 - Baller, Johannes
A1 - Prinz, Carsten
A1 - Graeber, Gustav
T1 - Sustainable, Low‐Cost Sorbents Based on Calcium Chloride‐Loaded Polyacrylamide Hydrogels
N2 - AbstractSorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high‐performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high‐performance, cost‐efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The achievable salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel‐salt composites are shown to be stable under repeated sorption‐desorption cycling and enable water uptakes of 0.92 and 2.38 grams of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost‐performance ratio substantially exceeds lithium chloride‐based systems. Further, the mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low‐cost sorbent materials for future applications in water and energy.
KW - Electrochemistry
KW - Condensed Matter Physics
KW - Biomaterials
KW - Electronic, Optical and Magnetic Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598366
DO - https://doi.org/10.1002/adfm.202314680
SN - 1616-301X
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - A Self-Driving Lab for Nano and Advanced Materials Synthesis
N2 - Nano- and advanced materials have been recognized as a key enabling technology of the 21st century, due to their high potential of driving innovations in new clean energy technologies, sustainable manufacturing by substitution of critical raw materials and replacement of hazardous substances, breakthroughs in energy conversion and storage, improvement of the environmental performance of products and processes, and facilitation of circularity. Consequently, new tools that enhance the development and optimization cycle of nano- and advanced materials are crucial.
In this contribution, we present our Self-Driving Lab (SDL) for Nano and Advanced Materials [1], that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nanomaterials – with automated characterization and data analysis, for a complete and reliable nanomaterial synthesis workflow. By fully automating the processing steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. The system also exhibits high modularity and adaptability in terms of reaction scales and incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence). We discuss the excellent reproducibility of the various materials synthesized on the platform in terms of particle size and size distribution, and the adaptability and modularity that allows access to a diverse set of nanomaterial classes.
We also present several key aspects of the central backend that orchestrates the (parallelized) syntheses workflows. One key feature is the resource management or “traffic control” for scheduling and executing parallel reactions in a multi-threaded environment. Another is the interface with data analysis algorithms from in-line, at-line, and off-line measurements. Here, we will give examples of how automatic image segmentation of electron microscopy images with the help of AI [2] can be used for reducing the “data analysis bottleneck” from an off-line measurement. We will also discuss various machine learning (ML) algorithms that are currently implemented in the backend and can be used for ML-guided, closed-loop material optimization in our SDL. Lastly, we will show our recent efforts [3] in making the workflow generation on SDLs more user-friendly by using large language models to generate executable workflows automatically from synthesis procedures given in natural language and user-friendly graphical user interfaces based on node editors that also allow for knowledge graph extraction from the workflows. In this context, we are currently also working on a common description or ontology for representing the process steps and parameters of the workflows, which will greatly facilitate the semantic description and interoperability of workflows between different SDL hardware and software platforms.
These features underscore the SDL’s potential as a transformative tool for advancing and accelerating the development of nano- and advanced materials, offering solutions for a sustainable and environmentally responsible future.
T2 - MRS Fall Meeting 2025
CY - Boston, MA, USA
DA - 30.11.2025
KW - Self-Driving Labs
KW - Materials Acceleration Platforms
KW - Advanced Materials
KW - Nanomaterials
KW - Automation
PY - 2025
AN - OPUS4-65129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Habibimarkani, Heydar
A1 - Prinz, Carsten
A1 - Sahre, Mario
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - CV, TEM, XRD and XPS/HAXPES datasets of FeNi-based nanoparticles for the oxygen evolution reaction
N2 - The datasets from Cyclic Voltammetry, Transmision Electron Microscopy, X-ray Diffraction, and (Hard Energy) X-ray Photoelectron Spectroscopy are related to the publication
H. Habibimarkani, S.-L. Abram, A. Guilherme Buzanich, C. Prinz, M. Sahre, V.-D. Hodoroaba and J. Radnik
"In-depth analysis of FeNi-based nanoparticles for the oxygen evolution reaction"
Scientific Reports (2025), https://doi.org/10.1038/s41598-025-92720-3
Details of the materials and the experimental procedures are described in this publications.
KW - Oxygen evolution reaction
KW - Fe-Ni nanopartices
KW - Comprehensive analysis
PY - 2025
DO - https://doi.org/10.5281/zenodo.14975964
PB - Zenodo
CY - Geneva
AN - OPUS4-63335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiodjio Sendja, Bridinette
A1 - Tchouank Tekou, Carol Trudel
A1 - Prinz, Carsten
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Adsorptive performance of single-walled carbon nanotubes for divalent manganese sorption characterized by X-ray absorption spectroscopy
N2 - The adsorptive performance of divalent manganese onto single-walled carbon nanotubes (SWCNTs) is investigated by X-ray absorption spectroscopy (XAS). The study is focused on the one hand, on the use of SWCNT as adsorbent to remove divalent manganese II) pollutant controlling batch parameters such as pH, adsorbent dose and contact time; and on the other hand, on the characterization of manganese adsorbed by SWCNT (Mn-SWCNT) adsorbent to probe the chemical composition, oxidation state, and local structural environment of Mn absorber. Freundlich adsorption isotherm well fitted the experimental data and suggested the maximum adsorption capacity at pH 2. Ion exchange was proposed as the main adsorption mechanism for removing manganese using SWCNT. XAS results revealed the change in the oxidation state of manganese. The effect of pH, adsorbent dose, and contact time is shown. XAS also showed that Mn-SWCNT material is principally composed of MnCl2, Mn2O3, MnO2, Mn3O4, and MnO in decreasing order with MnCl2 and Mn2O3 as major compounds.
KW - Local environment
KW - Single-walled carbon nanotubes
KW - Divalent manganese
KW - Adsorptive performance
KW - X-ray absorption spectroscopy
KW - Oxidation state
PY - 2025
DO - https://doi.org/10.1007/s11696-025-04418-5
SN - 0366-6352
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-64492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Michaelis, Matthias
A1 - Prinz, Carsten
A1 - Würth, Christian
T1 - Time-resolved luminescence spectroscopy for monitoring the stability and dissolution behaviour of upconverting nanocrystals with different surface coatings†
N2 - We demonstrate the potential of time-resolved luminescence spectroscopy for the straightforward assessment and in situ monitoring of the stability of upconversion nanocrystals (UCNPs). Therefore, we prepared hexagonal NaYF4:Yb3+,Er3+ UCNPs with various coatings with a focus on phosphonate ligands of different valency, using different ligand exchange procedures, and studied their dissolution behaviour in phosphate-buffered saline (PBS) dispersions at 20 °C and 37 °C with various analytical methods. The amount of the released UCNPs constituting fluoride ions was quantified by potentiometry using a Fluoride ion-sensitive electrode and particle disintegration was confirmed by transmission electron microscopy studies of the differently aged UCNPs. In parallel, the luminescence features of the UCNPs were measured with special emphasis on the lifetime of the sensitizer emission to demonstrate its suitability as Screening parameter for UCNP stability and changes in particle composition. The excellent correlation between the changes in luminescence lifetime and fluoride concentration highlights the potential of our luminescence lifetime method for UCNP stability screening and thereby indirect monitoring of the release of potentially hazardous fluoride ions during uptake and dissolution in biological systems. Additionally, the developed in situ optical method was used to distinguish the dissolution dynamics of differently sized and differently coated UCNPs.
KW - Fluorescence
KW - Lifetime
KW - Method
KW - Quantification
KW - Stability
KW - Coating
KW - Surface chemistry
KW - Lanthanide
KW - Fluoride
KW - Electrochemistry
KW - ICP-OES
KW - Upconversion
KW - Nano
KW - Particle
KW - Aging
KW - Quality assurance
KW - TEM
PY - 2020
DO - https://doi.org/10.1039/d0nr02931a
VL - 12
IS - 23
SP - 12589
EP - 12601
PB - Royal Society od Chemistry
AN - OPUS4-52088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stuff, Maria
A1 - Rübner, Katrin
A1 - Prinz, Carsten
A1 - Rische, N.
A1 - Chronz, M.
A1 - Kühne, Hans-Carsten
ED - Siegesmund, S.
ED - Middendorf, B.
T1 - Towards a better understanding of tuff stone deterioration
N2 - Stone deterioration is the result of a complex interaction of external physical, chemical and biological forces with the mineralogical-petrophysical properties of the stone. With a better understanding of how these properties are linked to material behavior and durability, more effective measures for stone conservation can be developed. Studying these interactions in tuff is particularly complex due to the naturally high heterogeneity of tuff rocks.
The first aim of a current research project is to combine the results of recent and older studies on tuff deterioration. Furthermore, the literature overview is complemented by our own investigation of Weibern and Ettringen tuff, with a focus on pore structure characteristics.
T2 - STONE - 14th international congress on the deterioration and conservation of stone
CY - Meeting was canceled
DA - 07.09.2020
KW - Pore structure
KW - Weathering
KW - Weibern tuff
KW - Ettringen tuff
PY - 2020
SN - 978-3-96311-172-3
SP - 805
EP - 810
PB - Mitteldeutscher Verlag
CY - Halle (Saale)
AN - OPUS4-51549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittrich, Maria
A1 - Paulo, Carlos
A1 - Knabe, Nicole
A1 - Sturm, Heinz
A1 - Zaitsev, Vladimir
A1 - Gorbushina, Anna
T1 - Microscopic Raman study of fungal pigment using the genetically amenable rock inhabitant Knufia petricola as a model organism
N2 - Fungal pigments such as melanin and carotenoids are distinctive markers of animal and plant pathogenic fungi as well as their environmental relatives. These complex pigments play important roles in pathogenicity and stress tolerance while also being useful as biomarkers. Accordingly, it is important to be able to identify in situ the pigments in black fungi, a group of clinical and environmental importance. In this study, wild-type and genetically modified strains of Knufia petricola A95 and wild fungal cells attached to ancient rock were investigated for their spectroscopic and microscopic Raman features and morphological appearance. Knockout mutants of melanin synthesis genes pks1 (polyketide synthase), sdh1 (scytalone dehydratase), and both pks1 and the carotenoid synthesis gene phd1 (phytoene desaturase) were studied We applied two different Raman microscopes using two lasers, with 633 nm and 488 nm wavelengths. We analyzed and compared Raman spectra between the measured reference substances and the mutant and wild-type strains. In the wild strain WT:A95, the peaks close to melanin peals were found at 1353 cm−1 and 1611 cm−1. There are no characteristic melanin peaks at 1580–1600 cm−1 and around 1350 cm−1 at the spectrum of the Δpks1/Δphd1 mutant and the Δsdh1 mutant. The Δpks1 mutant spectrum has the peaks at the beta-carotene v2 C-C in-plane stretch at 1155 cm−1 and v3 C-CH3 deformation at 1005 cm−1. The peaks of carotenoids and melanin were found in all mutants and the wild strain, except the Δpks1/Δphd1 mutant. Raman spectra allow for discrimination between the various pigments. Hence, interactions between natural fungal melanin, as well as other protective pigments, and complex environmental matrices can be characterized on a range of spatial and temporal scales.
KW - Raman Spectroscopy
KW - Instrumentation
KW - Analytical Chemistry
KW - Knufia petricola
KW - Confocal microscopy
KW - Atomic and Molecular Physics and Optics
PY - 2023
DO - https://doi.org/10.1016/j.saa.2023.123250
SN - 1386-1425
VL - 303
SP - 1
EP - 11
PB - Elsevier BV
AN - OPUS4-58792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Barkeshli, M.
A1 - Stephan, Ina
ED - Barkeshli, M.
ED - Arya, A.
ED - Nath, V.
ED - Abduraheem, K.
T1 - Sizing materials used in Persian manuscripts and their behaviour against the mould fungus Aspergillus flavus
N2 - Our earlier study based on historical and scientific analysis showed that Iranians used a considerable range of materials in the sizing process. Unlike many nations who used limited sizing materials to improve the mechanical strength and to smoothen the paper surface, Iranians have used various materials for sizing process from Taimurid (15th century) to Safawid (16th century) and Qajar (19th century) periods. Further to our earlier study on the Sizing Materials used in Persian manuscripts and miniature paintings, scientific analysis was carried out to investigate their behaviour against the mould fungus Aspergillus flavus. In the first stage fourteen different sizing materials that was identified from Persian historical recipes were reconstructed. In the second stage fungicidal property of each sizing samples against Aspergillus flavus fungus were identified that will be presented in this paper.
KW - Sizing
KW - Materials
KW - Persian manuscripts
KW - Deterioration
KW - Fungus
KW - Aspergillus flavus
PY - 2023
SN - 978-93-5461-714-0
SP - 3
EP - 20
PB - Daya Publishing House
CY - New Delhi
AN - OPUS4-58102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schraut, Katharina
T1 - Production of an alite-rich material from reduced basic oxygen furnace slags
N2 - Basic oxygen furnace slag (BOFS) is a by-product of steelmaking of which about 10.4 Mt are produced annually in the EU. BOFS is mostly used in road construction, earthwork and hydraulic engineering. However, in this use, the iron bound in BOFS is lost and the opportunity to produce higher value products from BOFS is forgone.
In recent decades, many researchers have investigated the production of both Portland cement clinker and crude iron from BOFS via a thermochemical reductive treatment. The reductive treatment of liquid BOFS causes a reduction of iron oxides to metallic iron, which separates from the mineral phase due to its higher density and can be recovered. An advantage of this process is that simultaneously the chemical composition of the reduced BOFS is adapted to that of Portland cement clinker and the hydraulic reactive mineral alite (Ca3SiO5) is formed.
In this study, German BOFS was reduced in a small-scale electric arc furnace and a low-iron mineral product rich in alite was produced. Despite a chemical and mineralogical composition similar to that of Portland cement clinker, the reduced BOFS produced less heat of hydration, and its reaction was delayed compared to Portland cement. However, adding gypsum accelerated the hydration rate of the reduced BOFS.
Further research to improve the hydraulic properties of the reduced BOFS is essential. If successful, the production of a hydraulic material and crude iron from BOFS could have economic and ecological benefits for both the cement and steel industry.
T2 - GeoBerlin 2023
CY - Berlin, Germany
DA - 04.09.2023
KW - BOFS
KW - Alite
KW - Hydraulic reactivity
PY - 2023
AN - OPUS4-58206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
T1 - Raw and processed X-ray scattering datasets for: "Entering a new dimension in powder processing for advanced ceramics shaping"
N2 - This dataset is a complete set of raw, processed and analyzed data, associated with the manuscript mentioned in the title.
All associated metadata and processing history has been added. Particle size distribution analyses using McSAS are included as well.
The samples consisted of a 4.2 mass% dispersion of yttria-stabilized zirconia nanoparticles in a cross-linked matrix. The measurements show a good dispersion with minimal agglomeration. The wide-angle region shows diffraction information consistent with zirconia.
KW - X-ray scattering
KW - Nanocomposite
KW - Ceramic microprinting
KW - Yttria-stabilized zirconia
KW - SAXS
KW - Nanomaterials
KW - Two-photon polymerization
KW - Transparency
KW - Mechanical testing
PY - 2023
DO - https://doi.org/10.5281/zenodo.7498647
PB - Zenodo
CY - Geneva
AN - OPUS4-56766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Fritzsche, Sven
A1 - Pauw, Brian Richard
A1 - Weimann, Christiane
A1 - Sturm, Heinz
T1 - Test artifact for fs-LDW
N2 - Data to generate the given graphs in the publication as well as raw images of the shown images.
KW - stl code
KW - Images
KW - Graphs
KW - Data
PY - 2023
DO - https://doi.org/10.5281/zenodo.7671945
PB - Zenodo
CY - Geneva
AN - OPUS4-58096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Zarinwall, A.
A1 - Waniek, Tassilo
A1 - Finke, B.
A1 - Sadaat, R.
A1 - Sturm, Heinz
A1 - Garnweitner, G.
ED - Sinapius, M.
ED - Ziegmann, G.
T1 - Particle Surface Modification
N2 - Whilst a decisive role of the particle-matrix interphase on the mechanical properties of nanoparticle-filled polymers has been demonstrated in the last years, the arbitrary design of this interphase remains a very challenging goal. In principle, this could be realized via an appropriate surfacemodification of the nanofiller prior to its incorporation in the polymer. For most systems, such as for boehmite nanofillers, however, the interaction of organic modifiers with the particle surface has not been studied in detail, and only single studies are known rather than systematic investiga- tions on the effects of different chemical functions anchored on the particle surface. In this chapter, we present an extensive study on the binding of APTES, a common silane surface modifier, with boehmite, and show that thermogravimetric analysis (TGA) coupled with mass spectrometry (MS) is a convenient and highly suitable method to elucidate the ligand binding in detail. Furthermore, a two-step coupling strategy is presented, demonstrating that based on APTES anchored to the parti- cle surface, the condensation of various carboxylic acids can be utilized to enable highly diverse chemical properties of the nanofillers, which leads to very different particle-matrix interactions in the nanocomposites.
KW - APTES
KW - Boehmite
KW - Nanoparticle
KW - TGA-MS
PY - 2021
SN - 978-3-030-68522-5
SN - 978-3-030-68523-2
DO - https://doi.org/10.1007/978-3-030-68523-2
SN - 2194-8240
SN - 2194-8259
SP - 119
EP - 142
PB - Springer Nature Switzerland AG
CY - Cham
AN - OPUS4-53727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roszak, I.
A1 - Oswald, L.
A1 - Ouahabi, A. A.
A1 - Bertin, Annabelle
A1 - Laurent, E.
A1 - Felix, O.
A1 - Carvin-Sergent, I.
A1 - Charles, L.
A1 - Lutz, J.-F.
T1 - Synthesis and sequencing of informational poly(amino phosphodiester)s
N2 - Sequence-defined poly(amino phosphodiester)s containing main-chain tertiary amines were synthesized by automated solid-phase phosphoramidite chemistry. These polymers were prepared using four monomers with different substituents. The formed polymers were characterized by HPLC and mass spectrometry. These methods evidenced preparation of molecularly-defined polymers. Furthermore, the presence of tertiary amines in the polymer backbones facilitates sequencing by tandem mass spectrometry.
KW - Poly(amino phosphodiester)
KW - Synthesis
KW - HPLC
KW - Mass spectrometry
PY - 2021
DO - https://doi.org/10.1039/d1py01052b
SN - 1759-9954
VL - 12
IS - 37
SP - 5279
EP - 5282
PB - Royal Society of Chemistry
AN - OPUS4-53732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schraut, Katharina
T1 - Portland cement clinker from reduced basic oxygen furnace slag
N2 - Basic oxygen furnace slag (BOFS) is a by-product of the steelmaking process, of which about 10.4 Mt are produced annually in the European Union. Besides its predominant use in road construction, earthwork, and hydraulic engineering, it is also possible to use BOFS as a source material for Portland cement clinker.
The main difference in the chemical composition of BOFS from the chemical composition of Portland cement clinker is its high content of iron oxides (7-50 wt.%). In recent decades, many researchers have investigated the production of both Portland cement clinker and crude iron from BOFS via thermochemical reductive treatment. Carbothermal treatment of liquid BOFS causes reduction of iron oxides to metallic iron, which separates from the mineral phase due to its higher density.
In this study, German BOFS was reduced in a small-scale electric arc furnace using petrol coke as reducing agent. The produced low-iron mineral product was chemically similar to Portland cement clinker and contained the most important Portland cement mineral alite (Ca3SiO5) as main component. Besides alite, the mineral product contained other Portland cement clinker constituents such as belite (β-Ca2SiO4) and tricalcium aluminate (Ca3Al2O6).
The production of Portland cement clinker and crude iron from BOFS has economic and ecological benefits for both the cement and steel industry. Cement clinker from reduced BOFS may be used as a substitute for cement clinker from conventional cement production, thereby CO2 emissions will be reduced. The steel industry benefits from a high-value application for its by-products that avoids cost expensive landfilling and may even bring economic advantages. However, reductive treatment requires high temperatures and, for economic reasons, has to be carried out immediately after casting of the liquid BOFS, which is a logistical challenge for most steel plants. A cost-benefit analysis is therefore essential.
T2 - European Congress and Exhibition on Advanced Materials and Processes
CY - Online meeting
DA - 13.09.2021
KW - BOFS
KW - Portland Cement
KW - Hydraulic reactivity
PY - 2021
AN - OPUS4-53475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schraut, Katharina
A1 - Adamczyk, Burkart
A1 - Adam, Christian
A1 - Stephan, D.
A1 - Meng, Birgit
A1 - Simon, Sebastian
A1 - von Werder, Julia
T1 - Synthesis and characterisation of alites from reduced basic oxygen furnace slags
N2 - Basic oxygen furnace slags (BOFS) are by-products of the steelmaking process. Several researchers have studied the production of Portland cement clinker and metallic iron from BOFS via a reductive treatment.
In this study, we applied a carbothermal reduction of BOFS in a technical-scale electric arc furnace and characterised the clinker-like products. Those clinker-like non-metallic products (NMPs) had a chemical and mineralogical composition comparable to clinker for ordinary Portland cement (OPC) and contained large elongated alite crystals as major component. The pure NMPs reacted more slowly and achieved a lower degree of hydration compared with commercial OPC.
If the reactivity of the products can be further increased by employing specific adaptations, it can be used as a full clinker substitute for OPC. Nevertheless, it is also an option to use the material without further modifications as a cement component or concrete addition, which contributes to the strength development in both cases.
KW - BOFS
KW - Hydration products
KW - Thermal analysis
KW - X-ray diffraction
PY - 2021
DO - https://doi.org/10.1016/j.cemconres.2021.106518
SN - 0008-8846
VL - 147
SP - 6518
PB - Elsevier Ltd.
AN - OPUS4-52939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zarinwall, A.
A1 - Waniek, Tassilo
A1 - Saadat, R.
A1 - Braun, U.
A1 - Sturm, Heinz
A1 - Garnweitner, G.
T1 - Comprehensive Characterization of APTES Surface Modifications of Hydrous Boehmite Nanoparticles
N2 - Hydrous boehmite (γ-AlOOH) nanoparticles (BNP) show great potential as nanoscale filler for the fabrication of fiber reinforced nanocomposite materials. Notably, the particle−matrix interaction has been demonstrated to be decisive for improving the matrix-dominant mechanical properties in the past years. Tailoring the surface properties of the nanofiller enables to selectively design the interaction and thus to exploit the benefits of the nanocomposite in an optimal way. Here, an extensive study is presented on the binding of (3-aminopropyl)triethoxysilane (APTES), a common silane surface modifier, on BNP in correlation to different process parameters (concentration, time, temperature, and pH). Furthermore, a comprehensive characterization of the modified BNP was performed by using elemental analysis (EA), thermogravimetric analysis (TGA) coupled with mass spectrometry (TGA-MS), and Kaiser’s test (KT). The results show an increasing monolayer formation up to a complete surface coverage with rising APTES concentration, time, and temperature, resulting in a maximal grafting density of 1.3 molecules/nm². Unspecific multilayer formation was solely observed under acidic conditions. Comparison of TGA-MS results with data recorded from EA, TGA, and KT verified that TGA-MS is a convenient and highly suitable method to elucidate the ligand binding in detail.
KW - Boehmite
KW - Nanoparticle
KW - Surface
KW - APTES
KW - Functionalization
KW - BET
KW - TGA
KW - Grafting
KW - Nanocomposite
KW - Silane
PY - 2020
DO - https://doi.org/10.1021/acs.langmuir.0c02682
VL - 37
IS - 1
SP - 171
EP - 179
PB - ACS Publications
AN - OPUS4-51954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schraut, Katharina
T1 - Hydraulic reactivity of alite rich material from post-treated basic oxygen furnace slags
N2 - Basic oxygen furnace slags (BOFS) are a by-product of steel production. In 2016, 10.4 Mt of BOFS were produced in the European Union (EU). The main part of BOFS is used in road construction, earthwork and hydraulic engineering. A smaller part is returned to the metallurgical circle, used as fertilizer or landfilled. However, it is also possible to produce higher value products from BOFS. For example, many researchers have investigated the possibility of producing Portland cement clinker and crude iron from BOFS by a carbothermal post-treatment.
In this study, German BOFS was reduced in a small-scale electric arc furnace using petrol coke as reducing agent. The carbothermal treatment reduces the iron oxides in the BOFS to metallic iron, which accumulates at the bottom of the furnace by density separation. In addition to metallic iron, the process generates a mineral product rich in the tricalcium silicate solid solution alite. As the main constituent of Portland cement clinker, the hydraulic reactive mineral alite is of high economic importance.
In previous studies, the hydraulic reactivity of the mineral product was investigated by testing the compressive strength of blends with 70 wt.% ordinary Portland cement (OPC). Recent investigations focused on the hydraulic properties of the pure mineral product from the reduced BOFS. The heat of hydration of the mineral product was measured by isothermal calorimetry and compared with the heat of hydration of a synthetic low-iron slag and OPC. In addition, the formation of hydration products was investigated with differential scanning calorimetry (DSC) and x-ray diffraction analysis (XRD) on freeze-dried samples after defined curing times. The results of the calorimetric measurements indicate that the mineral product produced less heat of hydration and its reaction was delayed compared to the synthetic low-iron slag and OPC. Hydration products such as portlandite and calcium silicate hydrates (C-S-H) formed later and in lower amounts.
The production of a hydraulic material from BOFS by reductive treatment is of great interest to both the cement and steel industries. The substitution of cement clinker in OPC with a hydraulic material such as reduced BOFS leads to a reduction in greenhouse gas emissions from cement production. The steel industry benefits from an application for its by-products that avoids cost expensive landfilling and may even bring economic advantages. Furthermore, it may be possible to return the recovered crude iron to production.
T2 - 3rd European Mineralogical Conference
CY - Cracow, Poland
DA - 30.08.2021
KW - BOFS
KW - Calcium silicate
KW - Hydraulic reactivity
PY - 2021
AN - OPUS4-53473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hägele, Gerhard
A1 - de Sousa Amadeu, Nader
A1 - Augner, Sven
A1 - Widler, Leo
A1 - Janiak, Christoph
T1 - Symmetric geminal bisphosphinic acids RR´C[P(CH3)(O)OH]2 - NMR and analytical studies
N2 - Four bisphosphinic acids RR´C[P(CH3)(O)OH]2 are characterized by 1H, 13Cf1Hg, and 31P{1H} NMR data. H3C-P-C-P-CH3 skeletons give rise to [A3X]2 spin systems. Some algebraic equations are derived for manual analysis of [A3X]2 spectra. HR NMR data for heteroaromatic substituents R in RC(H)[P(CH3)(O)OH]2 are reported. Dissociation constants and ion-specific chemical shifts dP of CH3C(OH)[P(CH3)(O)OH]2 are determined by 31P{1H} NMR controlled titrations of 2a.
KW - Biphosphinic acid J-Coupling
KW - High resulution NMR
PY - 2020
DO - https://doi.org/10.1080/10426507.2020.1798444
VL - 195
IS - 12
SP - 1013
EP - 1026
PB - Taylor & Francis
AN - OPUS4-61861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madbouly, Loay Akmal
T1 - Chemical analysis of commercial functionalized graphene along the production process
N2 - Graphene has found widespread commercial use, particularly in flexible electronics and coatings for substrates such as paper and textiles, in the form of suspensions and inks (Zhang et al., 2017). Functionalization of graphene allows fine-tuning of properties like electrical conductivity. Structural and chemical features of graphene materials are typically analyzed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). While Raman spectroscopy plays a critical role in identifying the presence of graphene and characterizing its structural defects (Pollard et al., 2017), XPS examines the chemistry of graphene. This study investigates three types of graphene materials — graphene (unfunctionalized, G-graphene), fluorine-functionalized graphene (F-graphene), and nitrogen-functionalized graphene (N-graphene) — across three physical forms: powders, suspensions, and embedded in inks. Functionalization was performed via plasma treatment of G-graphene with fluorine or ammonia gases. Suspensions were obtained by dispersing powders in distilled water, while inks were formulated using diacetone alcohol, carbon black, and graphene. Raman spectroscopy analysis confirmed the graphitic nature of all materials and revealed differences in defect density across different forms. The characteristic D, G, and D’ bands varied in relative intensity, offering insight into structural integrity and functionalization effects. XPS measurements examined core-level spectra (C 1s, F 1s, N 1s), revealing chemical bonding environments and hybridization states, including the sp² and sp³ states. A notable decline in fluorine content in F-graphene suspensions and inks, relative to powders, was observed. Existence of organic fluorine and total absence of metallic fluorine were observed. Raman spectroscopy and XPS data provided a correlated view of structural and chemical evolution through the graphene production chain (Figure 1).
T2 - RamanFest 2025
CY - Frankfurt, Germany
DA - 02.07.2025
KW - Functionalized graphene
KW - Graphene-related 2D materials (GR2M)
KW - Raman Spectroscopy
KW - XPS
KW - Inks
PY - 2025
AN - OPUS4-64114
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madbouly, Loay Akmal
T1 - Raman Spectroscopy and X-ray Photoelectron Spectroscopy of Commercial Functionalized Graphene
N2 - Graphene has been commercialized for over a decade. For many applications like flexible electronics, coating of different materials like paper or for textiles, it used in the form of suspensions or inks [1]. Graphene powders are typically used as the starting material for the synthesize of graphene suspensions and graphene inks. Functionalization enables tailoring the properties of graphene, such as the sheet resistance. X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, along other techniques are used to characterize graphene flakes, functionalized and otherwise. Raman spectroscopy is necessary as a primary step to validate the existence of graphene structure in graphene powders [2]. XPS is commonly used to investigate the elemental composition, including impurities, and the chemical structure of graphene.
In this study, we investigate the following set of commercial materials: fluorine-functionalized graphene (F-graphene) and nitrogen-functionalized graphene (N-graphene) as well as unfunctionalized graphene (G-graphene) in the forms of powders, suspensions, and inks. The functionalization process for the graphene powder was carried out in a plasma reactor by purging fluorine and ammonia gases, in separate processes, over the G-graphene powder. The suspensions were prepared by adding distilled water to the powders. The inks consist of diacetone alcohol, carbon black, and graphene powders.
Raman spectroscopy and XPS are complementary techniques. Our results obtained from Raman spectroscopy confirmed the existence of graphene structures in all samples and provided a comparative insight on the structural defects between samples. XPS was used to investigate the chemical states of elements in graphene, such as sp2 and sp3 hybridization states of carbon, as well as the chemical effect of functionalization on graphene. High resolution XPS analysis was performed for C 1s, F 1s and N 1s core-levels for all the graphene samples: G-graphene, F-graphene, and N-graphene, in all forms. The XPS results showed the elemental composition and the impurities of each sample. All powders showed less presence of carboxyl groups, compared to their respective suspensions and inks. F-functionalized suspension and inks showed a significant decrease in the at% of fluorine relative to the powder. These valuable insights, independent and when correlated, allowed the tracking of the structural and chemical changes of graphene along its production process.
T2 - E-MRS 2025
CY - Strasbough, France
DA - 26.05.2025
KW - Functionalized graphene inks
PY - 2025
AN - OPUS4-64113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Habibimarkani, Heydar
A1 - Abram, Sarah-Luise
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Prinz, Carsten
A1 - Sahre, Mario
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - In-depth analysis of FeNi-based nanoparticles for the oxygen evolution reaction
N2 - This study investigates the effect of varying iron-to-nickel ratios on the catalytic performance of Fe-Ni oxide nanoparticles (NPs) for the oxygen evolution reaction (OER). Addressing the issue of high energy wastage due to large overpotentials in OER, we synthesized and characterized different NP catalysts with different Fe: Ni oxide ratios. Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) were employed to determine the morphology, elemental and phase composition of the NPs. Furthermore, in-depth profiling with X-ray Photoelectron Spectroscopy (XPS) and Hard X-ray Photoelectron Spectroscopy (HAXPES) revealed that iron predominantly exists as oxide, while nickel exhibits both metallic and oxidic forms depending on the Fe content. XPS indicated an enrichment of iron at the NP surface, whereas HAXPES and EDS data agreed on the bulk stoichiometry. The assessment of the catalytic activity via cyclic voltammetry (CV) showed that the Fe: Ni ratio of 2:3 exhibited superior performance, characterized by lower overpotential and a smaller Tafel slope.
KW - Fe-Ni oxide
KW - Nanoparticles
KW - OER
KW - Catalytic performance
KW - Cyclic voltammetry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626932
UR - https://www.nature.com/articles/s41598-025-92720-3
DO - https://doi.org/10.1038/s41598-025-92720-3
VL - 15
IS - 1
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-62693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Habibimarkani, Heydar
T1 - Comparative chemical analysis of Ni-Fe oxide nanoparticles
N2 - Ni-Fe oxide nanoparticles have gained a lot of interest because of their high activity in the oxygen evolution reaction (OER) which is crucial for water splitting. [1] Although there have been great efforts in the last years, the understanding of the synergistic effect between Fe and Ni is still under discussion.
Therefore, we prepared different Ni-Fe oxide nanoparticles with different compositions from pure iron oxide to pure nickel oxide adapting a known procedure. [2,3] Size and morphology of the nanoparticles depend on the composition which was shown with Transmission Electron Microscopy (TEM). The compositions of the nanoparticles were measured with a comparative approach using X-ray Photoelectron Spectroscopy (XPS), Hard X-ray Photoelectron Spectroscopy (HAXPES), and Energy Dispersive X-Ray Spectroscopy (EDS) coupled with the TEM providing detailed chemical information of the nanoparticles in different sample regions. EDS reveals that the different sample regions are dominated by one of the components, Fe or Ni, but a slight mixing between the components can be found (see Figure 1), which was confirmed with X-ray Diffraction (XRD). XPS indicates the enrichment of Fe at the sample surface, while HAXPES and EDS data agree on the stoichiometry of the bulk. High-resolution XPS and HAXPES exhibit some differences in the valence states of Fe and Ni, whereas Ni seems to be easier to reduce than Fe. Further investigations combining these different techniques and additionally Secondary Ion Mass Spectrometry (ToF-SIMS) are ongoing by using in situ approaches and coupling cyclic voltammetry to the analytical techniques
T2 - SALSA Make and Measure 2024: Interfaces
CY - Berlin, Germany
DA - 11.09.2024
KW - (Hard) X-ray Photoelectron Spectroscopy
KW - Oxygen evolution reaction
KW - Synergistic effects
KW - TEM
PY - 2024
AN - OPUS4-62346
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sediqi, Salbin
T1 - Electrocatalytic carbon dioxide reduction on electrodeposited multi principal element alloy (MPEA) catalysts
N2 - The aim of this project is to develop novel noble metal free electrocatalysts that do not rely on critical minerals. We focus on Cu containing multi principal element alloys (MPEAs) improve the efficiency and selectivity of the CO 2 reduction reaction. In general, MPEAs consist of more than three elements that form solid solutions without intermetallic phases. The unique chemical composition and atomic level mixing introduces synergetic effects that play a critical role in electrocat alysis, especially in terms of selectivity. The nearly infinite combinations of elements that can be incorporated into MPEAs provide ample opportunities to tailor their functionality for various applications. This study presents the development of thin films based on CuNiZn MPEAs for CO 2 reduction reaction. The one step electrodeposition of CuNiZn gradient films was performed on carbon electrodes using a Hull cell under constant current or potential. The influence of pH, additives and current density or potential on the composition and mic rostructure of the films was characterized by scanning electron microscopy (SEM) and energy dispersive X ray spectroscopy (EDX). Atomic force microscopy (AFM) was used to study the topography and surface roughness of the CuNiZn films. The results indicate that the addition of ethylenediaminetetraacetic acid (EDTA) and citrate improves the uniformity and adhesion of the thin films. Electrochemical measurements, including cyclic voltammetry, linear sweep voltammetry, and impedance spectroscopy, were performed to investigate the electrocatalytic activity and corrosion resistance of CuNiZn thin films. The CuNiZn gradient films deposited in the Hull cell allow high throughput screening of the electrocatalytic activity. This approach has identified several compositions with high activity, selectivity and stability. Selected electrodeposited films were further processed to nanoparticles by means of pulsed laser ablation in liquids (PLAL). Further analysis thin film and nanoparticle electrocatalysts was performed with in line / at line product monitoring using a rotating disk electrode setup coupled to gas chromatography (GC) and high perform ance liquid chromatography (HPLC). The presentation will summarize the results of our screening study with few deep dives in selected compositions showing superior performance.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - CCMat
KW - Energy conversion
KW - Electrodeposition
KW - Electrocatalysis
PY - 2024
AN - OPUS4-62632
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sediqi, Salbin
T1 - Synthesis and characterization of multi-principal element alloys (MPEAs) for electrocatalysis applications
N2 - The aim of this project is the development of novel, noble metal-free electrocatalysts that do not rely on critical minerals. We focus on multi-principal element alloys (MPEAs), especially combinations involving Cu, to significantly enhance the efficiency of the CO2 reduction reaction. Generally, MPEAs consist of more than three elements, forming solid solutions without intermetallic phases. The unique disordered random structure introduces synergetic effects that play a critical role in electrocatalysis, particularly in terms of selectivity. The neraly-endless combinations of elements that can be incorporated in MPEAs offer ample opportunities to tailor its functionality for various applications.
This study presents the development of thin films based on NiZnCu MPEAs for the CO2 reduction reaction. The one-step electrodeposition of NiZnCu films was performed on Cu substrates in a single bath using a Hull cell under constant current or potential. The influence of pH, additives and current density or potential on the composition and microstructure of the films was characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Atomic force microscopy (AFM) was used to study the topography and surface roughness of the NiZnCu films. The results indicate that the addition of ethylenediaminetetraacetic acid (EDTA) and citrate enhances the uniformity and adhesion of the thin films.
Electrochemical measurements, including cyclic voltammetry, linear sweep voltammetry and impedance spectroscopy were conducted to study the electrocatalytic activity and the corrosion resistance of NiZnCu thin films. The NiZnCu gradient films deposited in the Hull cell enable high-throughput screening of the electrocatalytic activity. With this approach, multiple compositions showing high activity, selectivity and stability were identified. Further analysis with in line / at line product analysis was performed using a rotating disc electrode setup coupled to gas chromotography (GC) and high-performance liquid chromotography (HPLC). The presentation will summarize the results of our screening study with few deep-dives in selected compositions showing superior performance.
T2 - eMRS 2024 Spring Meeting
CY - Strasbourg, France
DA - 27.05.2024
KW - CCMat
KW - Energy conversion
KW - Electrocatalysis
PY - 2024
AN - OPUS4-62633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matiushkina, Anna
T1 - Synthesis and physical properties studies of bifunctional nanocomposites
N2 - At present, the field of research on nanostructures is actively developing, which is due to their unique physico-chemical properties compared to bulk materials. Many research activities are focused on obtaining nanocomposites, which combine various types of nanostructures with different properties and function. For example, the development of magneto-luminescent nanocomposites makes it possible to use their luminescence for optical imaging, and their magnetic properties for magnetic targeted delivery and as agents of hyperthermia and magnetic resonance imaging.
My master studies as part of the project Goszadanie 2019-1080 at ITMO were focused on the investigation of nanocomposites, consisting of semiconductor quantum dots (QDs) as luminescent component and superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic one, in solution and during their incubation with HeLa cells. The spectrally resolved analysis of the QD photoluminescence (PL) kinetics of the free QDs and the QDs incorporated in these nanocomposites undergoing energy transfer processes allowed for (1) understanding the reasons for the quenching of QD luminescence in cells, (2) evaluating the average distance between the QDs and, based on this, concluding the degree of QD aggregation in cells, and (3) drawing conclusions about the QD-quencher composites integrity in cells. Overall, the analysis of the PL kinetics confirmed that QDs and SPIONs remain bound in the obtained nanocomposites during incubation with cells.
To ensure the successful advancement of nanomaterials in biomedicine and the transition from their laboratory preparation and studies to their use in different applications and in industry, it is crucial to develop reliable measurement methods and reference materials candidates for the characterization of functional nanomaterials and assessing the quality of the obtained nanostructures. My recently started project at BAM, which is part of the EU metrology project MeTrINo, will be devoted to this topic. There we will focus on the development of methodologies for the synthesis and characterization of iron oxide nanoparticles, already used in biomedicine, and multi-element lanthanide-based nanoparticles with attractive upconversion luminescence, as reference materials with high monodispersity and reproducibility. Also, these nanoparticles will be functionalized with organic dyes for optical imaging and, probably, the study of the energy transfer phenomena.
T2 - Bad Honnef Summer School
CY - Bad Honnef, Germany
DA - 30.07.2023
KW - Quantum dots
KW - Iron oxide nanoparticles
KW - Upconversion nanoparticles
PY - 2023
AN - OPUS4-58075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Osipova, Viktoriia
T1 - Incorporation of near-infrared light emitting chromium (III) complexes into the core and shell of silica nanoparticles and optimisation of their optical properties
N2 - In recent years, chromium (III) complexes have received a lot of attention as novel near-infrared (NIR) emitters. This interest was triggered by the report on the first molecular ruby Cr(ddpd)2(BF4)3 with a high photoluminescence quantum yield of 13.7% of its near infrared (NIR) emission band and a long luminescence lifetime of 1.122 ms at room temperature. Meanwhile, the influence of triplet oxygen, temperature, and pressure on the optical properties of different molecular rubies have been assessed. These features make these molecular rubies promising candidates for multi-analyte optical sensing applications and the generation of singlet oxygen for photocatalysis and photodynamic therapy. However, in an oxygen-containing environment, the photoluminescence quantum yields and luminescence lifetimes of these chromium(III) complexes show only very small values. This hampers their application as NIR luminescence labels. This application, that cannot be tackled by conventional deoxygenating approaches, requires suitable strategies to protect the luminescence of the chromium(III) complexes from oxygen quenching. Typical approaches to reduce the oxygen sensitivity of long-lived luminophores include the encapsulation into an oxygen-shielding matrix or less commonly employed, by tuning the bulkiness of the ligands for oxygen-sensitive coordination compounds. An elegant approach to reduce the undesired luminescence quenching by triplet oxygen explored by us presents the incorporation of these chromium(III) complexes into amorphous, non-porous silica nanoparticles, that can be simply surface functionalized, e.g., with targeting ligands and/or other sensor molecules. This can enable the use of such chromium(III) complexes as reporters for bioanalytical assays and bioimaging without the need to introduce reactive groups into the ligands and can pave the road to lifetime tuning.
In this work, as first proof-of-concept experiments, a set of chromium (III) complexes constituting of different ligands and counter anions, were embedded into the core of silica nanoparticles. As an alternative synthesis strategy, selected complexes were incorporated into a silica shell formed around the core of self-made silica nanoparticles. Subsequently, the optical properties of the resulting luminescent silica nanoparticles were spectroscopically assessed by steady state and time-resolved luminescence spectroscopy. First results of time-resolved luminescence measurements of the Cr(ddpd)2(PF6)3 complex incorporated into 25nm large silica nanoparticles dispersed in aerated water in comparison to the decay kinetics obtained for this complex in acetonitrile in air showed an increase in lifetime from 46 µs to 1147 µs. This confirming our design concept of nanoscale NIR emissive Cr(III) reporters.
T2 - Bad Honnef summer school
CY - Bad Honnef, Germany
DA - 30.07.2023
KW - Chromium (III) complexes
KW - Silica Nanoparticles
KW - Luminescence lifetime measurments
PY - 2023
AN - OPUS4-58076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Habibimarkani, Heydar
T1 - Investigating the Synergistic Effects of FeNi-Oxide Nanoparticles as Water Electrolysis Catalysts: A Multi-Technique Characterization Approach
N2 - Electrocatalysis is and will continue to play a central role in the development of a new and modern sustainable economy, especially for chemicals and fuels. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution in this economic sector. A major drawback of electrical energy lies in the storage. Therefore, hydrogen is discussed as promising alternative. Fortunately, this issue can be effectively addressed through the implementation of chemical storage mechanisms. Due to their abundance on Earth and inherent stability in alkaline solutions, transition-metal oxides have become one of several viable alternatives to conventional noble-metal catalysts. Since FeNi oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research.
A series of different types of FeNi oxide nanoparticles (NPs) with atomic ratios covering a broad range, and various sizes with specific stoichiometric and non-stoichiometric iron and nickel ratios was synthesized and characterized by the combination of surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The morphology was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the coexistence of mixed and unmixed iron and nickel NPs with comparable sizes in the range of 30–40 nm across all ratios. The synthesis technique displayed control over the iron-nickel ratio, as evidenced by energy dispersive X-ray spectroscopy (EDS) data. The presence of magnetite (Fe3O4) was detected in all samples investigated by X-ray diffraction (XRD). Furthermore, the existence of nickel ferrite (NiFe2O4) was shown in the Fe2Ni by XRD analysis. For the cyclic voltammetry (CV) measurements, the NPs were deposited onto glassy carbon electrodes using Nafion® as an ionomer, and 1 M KOH was employed as the electrolyte. Subsequently, the NPs/Nafion® electrode was transferred into the ToF-SIMS chamber to allow surface analysis and depth profiling.
The ToF-SIMS analysis revealed distinct peaks corresponding to Fe, Ni, and other peaks associated with Nafion®, whereas a straightforward correlation between the Ni.Fe ratio and the SIMS peak pattern is not possible.
The catalytic activity towards OER was evaluated through CV measurements, where the Fe2Ni3 ratio exhibited the most favorable performance, displaying a lower overpotential.
T2 - European Materials Research Society (E-MRS) Fall 2023
CY - Warsaw, Poland
DA - 18.09.2023
KW - FeNi-Oxide NPs
KW - ToF-SIMS
KW - Catalysts
KW - OER
PY - 2023
AN - OPUS4-59139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Habibimarkani, Heydar
T1 - Complementary Characterization of FeNi-Oxide Nanoparticles as Catalysts for Water Electrolysis combining Electron Microscopy, EDS, XRD, ToF-SIMS and Electrochemical Analysis
N2 - Electrocatalysis is and will continue to play a central role in the development of a new and modern sustainable economy, especially for chemicals and fuels. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution in this economic sector. A major drawback of electrical energy lies in the storage. Therefore, hydrogen is discussed as promising alternative. Fortunately, this issue can be effectively addressed through the implementation of chemical storage mechanisms. Due to their abundance on Earth and inherent stability in alkaline solutions, transition-metal oxides have become one of several viable alternatives to conventional noble-metal catalysts. Since FeNi oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research.
A series of different types of FeNi oxide nanoparticles (NPs) with atomic ratios covering a broad range, and various sizes with specific stoichiometric and non-stoichiometric iron and nickel ratios was synthesized and characterized by the combination of surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The morphology was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed the coexistence of mixed and unmixed iron and nickel NPs with comparable sizes in the range of 30–40 nm across all ratios. The synthesis technique displayed control over the iron-nickel ratio, as evidenced by energy dispersive X-ray spectroscopy (EDS) data. The presence of magnetite (Fe3O4) was detected in all samples investigated by X-ray diffraction (XRD). Furthermore, the existence of nickel ferrite (NiFe2O4) was shown in the Fe2Ni by XRD analysis. For the cyclic voltammetry (CV) measurements, the NPs were deposited onto glassy carbon electrodes using Nafion® as an ionomer, and 1 M KOH was employed as the electrolyte. Subsequently, the NPs/Nafion® electrode was transferred into the ToF-SIMS chamber to allow surface analysis and depth profiling.
The ToF-SIMS analysis revealed distinct peaks corresponding to Fe, Ni, and other peaks associated with Nafion®, whereas a straightforward correlation between the Ni.Fe ratio and the SIMS peak pattern is not possible.
The catalytic activity towards OER was evaluated through CV measurements, where the Fe2Ni3 ratio exhibited the most favorable performance, displaying a lower overpotential.
T2 - SIMS Europe 2023
CY - Nottingham, England
DA - 02.09.2023
KW - FeNi-Oxide NPs
KW - ToF-SIMS
KW - Catalysts
KW - OER
PY - 2023
AN - OPUS4-59143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavasolyzadeh, Zeynab
A1 - Tang, Peng
A1 - Hahn, Marc Benjamin
A1 - Hweidi, Gada
A1 - Nordholt, Niclas
A1 - Haag, Rainer
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - 2D and 3D Micropatterning of Mussel‐Inspired Functional Materials by Direct Laser Writing
N2 - AbstractThis work addresses the critical need for multifunctional materials and substrate‐independent high‐precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel‐inspired materials (MIMs) is combined with state‐of‐the‐art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub‐micron to micron resolution and extensive post‐functionalization capabilities. This study includes polydopamine (PDA), mussel‐inspired linear, and dendritic polyglycerols (MI‐lPG and MI‐dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single‐stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential.
KW - Direct laser writing
KW - Mussel-inspired materials
KW - Polyglycerol
KW - Polydopamine
KW - Micropatterning
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588778
DO - https://doi.org/10.1002/smll.202309394
SN - 1613-6829
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-58877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madbouly, Loay Akmal
A1 - Sturm, Heinz
A1 - Doolin, Alexander
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Chemical Analysis of Commercial Functionalized Graphene Nanoplatelets along the Production Process with Raman Spectroscopy and X-ray Photoelectron Spectroscopy
N2 - Commercial applications increasingly rely on functionalized graphene nanoplatelets (GNPs) supplied as powders, aqueous suspensions, and printable inks, yet their process−structure−property relationships across the production chain remain to be fully mapped. Here we apply a correlative Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS) workflow to nine independent industrial graphene batches spanning three surface chemistries, raw (R), fluorinated (F), and nitrogen-functionalized (N), in all three physical forms which are powders, suspensions, and inks.
Raman mapping (with a 532 nm excitation laser) showed that I2D/IG is highest for N samples and lowest for R-ink. A 2D-vs-G correlation places all samples on a trajectory parallel to the pure-doping vector, which can correlate to holes in the graphene lattice. The mean point-defect spacing is LD = 8.4−10.0 nm. High-resolution XPS resolves the accompanying chemical changes: F-powder exhibits distinct C−F (289 eV), C−F2 (292 eV), and C−F3 (293 eV) components and loses roughly half its F content upon dispersion in deionized water or ink formulation; inks of all chemistries show a pronounced O−C=O peak near 289−290 eV originated from the ink compounds. N-functionalized samples showed a prominent C−N (285.5 eV) only for the ink formulated N-functionalized sample. This study establishes a process-aware blueprint linking the functionalization route and formulation step to lattice disorder and surface chemistry, offering transferable quality-control metrics for graphene supply chains in industrial products/applications such as coatings, storage devices, and printed electronics.
KW - Functionalized graphene
KW - Raman Spectroscopy
KW - XPS
KW - Chemical analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652548
DO - https://doi.org/10.1021/acs.jpcc.5c06820
SN - 1932-7447
VL - 129
IS - 50
SP - 22033
EP - 22040
PB - American Chemical Society (ACS)
AN - OPUS4-65254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Topolniak, Ievgeniia
A1 - Knigge, Xenia
A1 - Radnik, Jörg
A1 - Sturm, Heinz
T1 - Maskless Micropatterning of Polydopamine for versatile surface functionalization
N2 - Inspired by the chemistry of mussel adhesive proteins, polydopamine (PDA has been shown as one of the most versatile platforms for altering the properties and incorporating new functionalities to nearby any material surface despite its nature. Rich chemistry of PDA enables broad variety of surface modification and diverse secondary reactions that makes it extremely interesting for a wide range of application including biomedical field, e.g., drug delivery, adhesives, cell adhesion, biosensing. Despite high potential of polydopamine, the lack of deposition control and precision in existed methods limits their applications in microdevices and miniaturized functional systems like, for example, MEMS, microfluidic and sensorics.
Herein, we demonstrate a novel maskless approach for surface micropatterning with polydopamine based on Multiphoton Lithography that overcomes present limitations. Neither strong oxidants, metal ions nor adjustment of pH to alkaline is required by this technique. The spatial resolution down to 0.8 µm has been achieved which is at least an order of magnitude smaller than shown by other existed methods. We are able to control the morphology and thickness of the micropattern by altering fabrication parameters allowing structure gradient.
Apart from the glass substrate, we achieved PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips. Post-modification of polydopamine micropatterns with protein enzyme like trypsin is demonstrated to highlight its sensing potential.
Presented in this work microfabrication technique empowers advanced applications of mussel-inspired materials in single-molecule bioassays, sensors and other complex microdevices.
T2 - International Conference on Precision Engineering and Sustainable Manufacturing
CY - Okinawa, Japan
DA - 18.07.2023
KW - Multiphoton lithography
KW - Polydopamine
KW - Micropatterning
PY - 2023
AN - OPUS4-58878
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brandić Lipińska, M.
A1 - Davenport, R.
A1 - Imhof, A. B.
A1 - Waclavicek, R.
A1 - Fateri, M.
A1 - Meyer, Lena
A1 - Gines-Palomares, J. C.
A1 - Zocca, Andrea
A1 - Makaya, A.
A1 - Günster, Jens
T1 - PAVER - Contextualizing laser sintering within a lunar technology roadmap
N2 - The Global Exploration Strategy of the International Space Exploration Coordination Group (ISECG) describes a timeframe of 2020 and beyond with the ultimate aim to establish a human presence on Mars towards the 2040ies. The next steps lie on the Moon with a focus on the coming 10 years. Early lunar surface missions will establish a capability in support of lunar science and prepare and test mission operations for subsequent human exploration of Mars and long-duration human activities on the Moon.
Given the extreme costs involved in the shipping of material from Earth, a prerequisite for future human exploration is the manufacturing of elements directly on the Moon’s surface. Unlike the equipment, which at the beginning will have to be brought from Earth, raw materials and energy could be available following the concept of In-Situ Resource Utilization. The ESA OSIP PAVING THE ROAD (PAVER) study investigates the use of a laser to sinter regolith into paving elements for use as roadways and launch pads thus mitigating dust issues for transport and exploration vehicles.
The ESA-funded study examines the potential of using a laser (12 kW CO2 laser with spot beam up to 100 mm) for layer sintering of lunar and martian regolith powders to manufacture larger 3D elements and provide know-how for the automatic manufacture of paving elements in the lunar environment. The project contributes to the first step toward the establishment of a lunar base and will lead to the construction of equipment capable of paving areas and manufacturing 3D structures.
PAVER project sets the starting point for an examination of the larger context of lunar exploration. Mission scenarios will look at different phases of lunar exploration: Robotic Lunar Exploration, Survivability, Sustainability, and Operational Phase. A proposed Technology Roadmap investigates the mission scenario and analyses how, and to which extent, laser melting/sintering will play a role in the various phases of exploration. The paper contextualizes laser sintering within selected mission scenarios and discusses the different kinds of infrastructure that can be produced at each phase of the mission. The outcome of the study includes the detailing of the TRL steps in the project and an outline of a timeline for the different elements. Covered aspects include terrain modelling such as operation pads, roadways, or towers, non-pressurized building structures to protect machinery, and habitat envelopes, to protect and shield humans against dust, micrometeoroids, and radiation.
T2 - 73rd International Astronautical Congress (IAC)
CY - Paris, France
DA - 18.09.2022
KW - Additive manufacturing
KW - Solar sintering
KW - ISRU
KW - Infrastructure
KW - Lunar habitat
KW - Paving
PY - 2022
SP - 1
EP - 9
AN - OPUS4-56519
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Aristia, Gabriela
A1 - Nofz, Marianne
A1 - Bäßler, Ralph
A1 - Sojref, Regine
A1 - Le, Quynh Hoa
T1 - Preliminary Study on Al2O3 Sol-Gel Coating for Corrosion Protection of Martensitic Stainless Steel in Artificial Geothermal Water
N2 - Al2O3 coatings are often used as protective layers on steels against electrochemical and high-temperature corrosion because they are chemically inert and stable at elevated temperatures. This study presents preliminary work on the possibilities of using Al2O3 sol-gel coatings for corrosion protection of martensitic stainless steels in geothermal environments. Al2O3 sol-gel coatings were applied on UNS S42000, which is known to be susceptible to uniform and localized corrosion. The coated steel specimens were then tested in two types of artificial geothermal water, which simulate the geothermal fluids found in Sibayak (SBY), Indonesia, and North German Basin (NGB), Germany, respectively. SBY has pH 4 and 1.5 g/L of chloride ions, whereas NGB has a pH of 6 and 166 g/L of chloride ions. All experiments were carried out in autoclaves at 150 °C and 1 MPa under the deaerated condition. Evaluations were performed by investigating the surface profiles of both uncoated and coated steels before and after the corrosion test using a Laser Scanning Microscope (LSM) and Scanning Electron Microscope (SEM). Finally, Electrochemical Impedance Spectroscopy (EIS) was performed to compare the corrosion resistance of Al2O3 coated steels in SBY and NGB solutions. It was observed from the corrosion test that Al2O3 coatings are more suitable for use in the geothermal water with a higher pH.
T2 - AMPP Annual International Corrosion Conference 2021
CY - Online Meeting
DA - 19.04.2021
KW - Protective coating
KW - Sol-gel coating
KW - Geothermal
KW - Martensitic steel
KW - Corrosion
PY - 2021
SP - 16777-01
EP - 16777-12
CY - Houston
AN - OPUS4-52501
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller-Elmau, Johanna
A1 - Meyer, Frank
A1 - Goebbert, Christian
A1 - Günster, Jens
T1 - Manufacturing Ceramics with Light
N2 - Additive manufacturing of extremely complex and filigree geometries from ceramic materials is a fascinating topic as ceramic materials are especially suitable for extremely small structures thanks to their physicochemical properties: they are chemically stable and do not corrode, while exhibiting unique mechanical properties especially in the micrometre range (Fig. 1). In addition, the ceramic structures made of yttria-stabilized zirconia (YSZ) shown in the figure are transparent, which makes them interesting candidates for the development of miniaturized optical components. The refractive index of YSZ measures 2,2 and is therefore considerably higher than that of polymer-based materials or glasses. The possibility of building this type of structure is enabled with the use of ceramic slurries with sufficiently high Transparency for the volumetric process of two-photon polymerization, which uses a femtosecond-short-pulse laser to structure photo-crosslinkable resins in the volume of one droplet. Slurries with even further optimized transparency allow even the application of xolography, a volumetric process that builds components with relatively low resolution, but in relatively large volumes and higher productivity. In the scope of the research presented here, for the first time, this process is applied to sintered ceramic materials. To be able to use minute ceramic structures as real components, an approach for the hybridization of processes ispresented in which components in the centimetre range, with relatively low resolution, are combined with very high-resolution nanostructures.
KW - Additive manufacturing
KW - Zirconia
KW - Two-photon-polymerization
KW - Nanopowder
PY - 2025
SN - 0173-9913
VL - 4
SP - 34
EP - 41
PB - Göller Verlag GmbH
CY - Baden-Baden
AN - OPUS4-65070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Compatibility of polymers exposed to heating oil blends with 10 % and 20 % biodiesel (FAME)
N2 - Biodiesel (FAME) from rapeseed is an environmentally friendly alternative to common fossil fuels. It is also suitable to serve as blending component to fuels like heating oil. If the fuel composition is changed, materials compatibility must be guaranteed. Adding polar biodiesel to nonpolar heating oil, changes the blend’s solvency and might cause swelling, extraction and solvation of polymers.
The objective of this research was to investigate the compatibility of polymeric materials, which are commonly used for components in middle distillate facilities, along with blends of heating oil and 20 % biodiesel (B20). For this propose, ACM, HNBR, FKM, PE, PA 6, POM, PUR and PVC were exposed to heating oil and B20 for 42 and 84 days at 40 °C. In addition, the polymers HNBR, FKM, PA, POM and PVC were also exposed at 70 °C. Furthermore, the resistance of polymers in eight-year aged B10 at 40 °C was evaluated. Ageing of biodiesel increases acidity which might propagate polymer corrosion.
The materials were evaluated as resistant, if the loss in tensile properties (tensile strength and elongation at break) and Shore hardness remained under 15 % compared to the initial unexposed material values. For investigations under compressed conditions, the compression set was determined for specimens of ACM, FKM and HNBR after exposure in heating oil B0 and B20 for 3,7,14, 28, 56 and 90 days at 40 °C according to ISO 815-1.
It was found that the resistance in B20 at 40 °C was given for all tested polymers except PUR. In the 8 years aged B10, PUR and POM were not compatible and ACM just conditionally compatible. At 70 °C, FKM and PVC were resistant in B20, whereas HNBR and PA 6 were not compatible. Swelling occurred for the elastomers ACM, HNBR and PUR.
T2 - AMPP Annual International Corrosion Conference
CY - Online Meeting
DA - 19.04.2021
KW - Biodiesel
KW - FAME
KW - RME
KW - Polymer in fuels
KW - Corrosion
PY - 2021
AN - OPUS4-52498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geffroy, P.-M.
A1 - Schubert, Nils Hendrik
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Quantification of in-plane stress development during drying of tape-cast ceramic layers by cantilever deflection method
N2 - The control of stress development in cast ceramics during drying is usually one of critical steps in ceramic processes, which is important also for additive manufacturing technologies using a suspension as feedstock. This work introduces a method based on the cantilever deflection method, to simultaneously quantify the kinetics of solvent evaporation, the shrinkage and the intensity of in-plane stresses developed during drying. Particular attention is given here to the experimental limits of the method and to the optimization of the experimental conditions to suitably measure the intensity of in-planar stress in the coating. The optimized method is applied to
four alumina slurries for the water-based additive manufacturing technology LSD-print. Four stages of drying are identified and discussed in relation with the granulometry and morphology of the alumina ceramic particles.
KW - Additive Manufacturing
KW - Tape casting
KW - Ceramic layers
KW - Drying stress
PY - 2025
DO - https://doi.org/10.1016/j.jeurceramsoc.2024.116868
VL - 45
IS - 1
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-61044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bäßler, Ralph
A1 - Amela Keserović, Amela
A1 - Sobetzki, Joana
A1 - Sarmiento Klapper, Helmuth
A1 - Dimper, Matthias
T1 - Geeignete Werkstoffe für Geothermieanwendungen (2)
N2 - Durch Auslagerungs- und elektrochemische Tests im Labor kann das Korrosionsverhalten verschiedener metallener Werkstoffe beurteilt werden. Aus den Versuchsergebnissen, die in verschiedenen synthetischen Geothermalwässern im Labor erzielt wurden, lassen sich die folgenden Schlussfolgerungen ziehen:
• Die Anfälligkeit für Spaltkorrosion wurde als wichtigster Aspekt für die Werkstoffqualifizierung ermittelt.
• Der niedriglegierte Stahl 25CrMo4 zeigte bei niedrigem Salzgehalt in MB-Geothermalwasser eine gleichmäßige Korrosion unterhalb der akzeptierten Schwelle von 0,3 mm/Jahr. Daher kann er als geeignet für geothermische Bedingungen mit niedrigem Salzgehalt angesehen werden, wie sie für MB getestet wurden. Es besteht keine Notwendigkeit, auf höherlegierte (teurere) Werkstoffe auszuweichen. Ein niedrigerer pH-Wert (wie bei LHD) führt zu Korrosionsraten oberhalb der akzeptablen Grenzwerte, so dass die niedriglegierten Werkstoffe nicht für Flüssigkeiten mit niedrigem pH-Wert geeignet sind.
• Stark salzhaltige Geothermalwässer erfordern höherlegierte Werkstoffe, da die Korrosionsrate von niedriglegiertem Stahl zu hoch ist.
• Der Duplexstahl X2CrNiMo22-5-3 und der Superduplexstahl X2CrNiMoCuWN25-7-4 wurden aufgrund ihrer kritischen Anfälligkeit für örtliche Korrosion in Form von Loch- und Spaltkorrosion unter Betriebsbedingungen nicht als geeignet für geothermische Anwendungen in Geothermalwässern mit einer mit NDB und ORG vergleichbaren Zusammensetzung angesehen.
• Der superaustenitische Stahl X1CrNiMoCu32-28-7 eignet sich für ORG und salzarme Wässer. In NDB-Geothermalwasser wurde er bei 100 °C als geeignet angesehen. Jedoch schränkt seine Anfälligkeit für Spaltkorrosion seine Anwendbarkeit ein. Neben seiner guten Korrosionsbeständigkeit ist sein Repassivierungsverhalten für seine begrenzte Anwendbarkeit in Geothermalwässern mit niedrigem pH-Wert verantwortlich.
• Die Nickelbasislegierung NiCr23Mo16Al wurde als geeignet erachtet und stellt eine sichere Option für den Einsatz in geothermischen Anlagen dar, selbst wenn mit stark salzhaltigem Geothermalwasser gearbeitet wird.
KW - Geothermie
KW - Korrosion
KW - Legierungen
KW - Anlagensicherheit
PY - 2024
SN - 0016-4232
VL - 2024
IS - 3
SP - 370
EP - 374
PB - Eugen G. Leuze Verlag
CY - Bad Saulgau
AN - OPUS4-59997
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bäßler, Ralph
A1 - Amela Keserović, Amela
A1 - Sobetzki, Joana
A1 - Sarmiento Klapper, Helmuth
A1 - Dimper, Matthias
T1 - Geeignete Werkstoffe für Geothermieanwendungen (1)
N2 - Durch Auslagerungs- und elektrochemische Tests im Labor kann das Korrosionsverhalten verschiedener metallener Werkstoffe beurteilt werden. Aus den Versuchsergebnissen, die in verschiedenen synthetischen Geothermalwässern im Labor erzielt wurden, lassen sich die folgenden Schlussfolgerungen ziehen:
• Die Anfälligkeit für Spaltkorrosion wurde als wichtigster Aspekt für die Werkstoffqualifizierung ermittelt.
• Der niedriglegierte Stahl 25CrMo4 zeigte bei niedrigem Salzgehalt in MB-Geothermalwasser eine gleichmäßige Korrosion unterhalb der akzeptierten Schwelle von 0,3 mm/Jahr. Daher kann er als geeignet für geothermische Bedingungen mit niedrigem Salzgehalt angesehen werden, wie sie für MB getestet wurden. Es besteht keine Notwendigkeit, auf höherlegierte (teurere) Werkstoffe auszuweichen. Ein niedrigerer pH-Wert (wie bei LHD) führt zu Korrosionsraten oberhalb der akzeptablen Grenzwerte, so dass die niedriglegierten Werkstoffe nicht für Flüssigkeiten mit niedrigem pH-Wert geeignet sind.
• Stark salzhaltige Geothermalwässer erfordern höherlegierte Werkstoffe, da die Korrosionsrate von niedriglegiertem Stahl zu hoch ist.
• Der Duplexstahl X2CrNiMo22-5-3 und der Superduplexstahl X2CrNiMoCuWN25-7-4 wurden aufgrund ihrer kritischen Anfälligkeit für örtliche Korrosion in Form von Loch- und Spaltkorrosion unter Betriebsbedingungen nicht als geeignet für geothermische Anwendungen in Geothermalwässern mit einer mit NDB und ORG vergleichbaren Zusammensetzung angesehen.
• Der superaustenitische Stahl X1CrNiMoCu32-28-7 eignet sich für ORG und salzarme Wässer. In NDB-Geothermalwasser wurde er bei 100 °C als geeignet angesehen. Jedoch schränkt seine Anfälligkeit für Spaltkorrosion seine Anwendbarkeit ein. Neben seiner guten Korrosionsbeständigkeit ist sein Repassivierungsverhalten für seine begrenzte Anwendbarkeit in Geothermalwässern mit niedrigem pH-Wert verantwortlich.
• Die Nickelbasislegierung NiCr23Mo16Al wurde als geeignet erachtet und stellt eine sichere Option für den Einsatz in geothermischen Anlagen dar, selbst wenn mit stark salzhaltigem Geothermalwasser gearbeitet wird.
KW - Geothermie
KW - Korrosion
KW - Legierungen
KW - Anlagensicherheit
PY - 2024
SN - 0016-4232
VL - 2024
IS - 2
SP - 240
EP - 243
PB - Eugen G. Leuze Verlag
CY - Bad Saulgau
AN - OPUS4-59996
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dinter, Adelina-Elisa
T1 - Deciphering corrosion processes of MIC organisms - single cell-ICP-ToF-MS analysis of archaea on solid steels
N2 - ICP-ToF (time of flight) MS enables the analysis of the multi-element fingerprint of single cells. The single cell ICP-ToF-MS is used in the presented poster for the analysis of archaea involved in microbiologically influenced corrosion (MIC) of steel. By means of sc-ICP-ToF-MS, the possible uptake of individual elements from the respective steel is investigated - the information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts. The work combines modern methods of analytical sciences with materials.
T2 - SALSA - Make & Measure 2021
CY - Online meeting
DA - 16.09.2021
KW - Sc-ICP-ToF-MS
KW - Single cell analysis
KW - Microbiologically influenced corrosion
KW - Archaea
KW - Poster presentation
PY - 2021
AN - OPUS4-53337
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
A1 - Stoljarova, A.
A1 - Regenspurg, S.
T1 - Influence of Precipitating Brine Components on Materials Selection for Geothermal Applications
N2 - Since geothermal wells are a feasible energy source to replace fossil fuel supply, many technologies have been developed to take advantage of geothermal energy. Nevertheless, service conditions in geothermal facilities are in many cases extreme in terms of corrosion due to the chemical composition of hydrothermal fluids and temperatures. Therefore, materials selection based on preliminary material qualification is essential to guarantee a secure and reliable operation of the facilities. During operation of a geothermal research facility in Groß Schönebeck copper and lead effects have been found downhole. Occurring mechanisms and measures to prevent precipitation or scaling needed to be investigated as well as potential influences of such precipitates on corrosion resistance of metallic materials used for equipment.
This contribution deals with the evaluation of the corrosion behavior of carbon steel and corrosion resistant alloys in copper and/or lead containing artificial geothermal water, simulating the conditions in the Northern German Basin.
The behavior of these materials in an artificial geothermal water obtained by electrochemical measurements and exposure tests are presented. While carbon steel exhibits precipitation and deposition, higher alloyed material shows different response to such species and a higher resistance in saline geothermal water.
Basing on these results the suitability of the investigated corrosion resistant alloy is given for use in such conditions, whereas carbon steel creates difficulties due to its susceptibility to Cu- and Pb-precipitation.
T2 - World Geothermal Congress
CY - Online meeting
DA - 30.03.2021
KW - Copper
KW - Lead
KW - Corrosion
KW - Steel
KW - Geothermal energy
PY - 2021
SP - 1
EP - 11
AN - OPUS4-52828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
T1 - Laser beam melting additive manufacturing at μ-gravity
N2 - At the Workshop "Neutron and Synchrotron Monitoring in Aerospace Advanced Manufacturing" at the Institute of Materials Physics in Space, German Aerospace Center (DLR) in Cologne, we presented on the opportunities and our experiences of using a powder based additive manufacturing process for in-space manufacturing applications in microgravity.
T2 - Workshop 'Neutron and Synchrotron Monitoring in Aerospace Advanced Manufacturing'
CY - Cologne, Germany
DA - 11.08.2022
KW - Additive manufacturing
KW - In-space manufacturing
KW - Microgravity
KW - μ-gravity
KW - Laser beam melting
KW - Advanced manufacturing
KW - Aerospace
KW - Process monitoring
PY - 2022
AN - OPUS4-56521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller-Elmau, Johanna
T1 - 2PP of ceramic
N2 - Photon-based additive manufacturing technologies such as SLA, DLP, LCM, moreover volumetric two-photon-polymerization (2PP), Xolography and holographic technologies promise the highest accuracy and dimensional freedom. To transfer the light through the feedstock it needs sufficient transparency. Ceramic particles used for powder processing routes act as scattering sites and therefore hinder the light transmission, unless…
The particle size and particle size distribution are chosen small and narrow enough. Particles smaller than roughly 1/10th of the light wavelength, mostly nanoparticles around 5nm size, decrease scattering vastly. This turns resins even with homogeneously distributed ceramic weight fraction of up to 80% transparent again. Feedstocks were prepared for the highly accurate two-photon-polymerization gaining the smallest yttria stabilized zirconia structures with a resolution of 500nm and unique mechanical properties.
The same feedstock was applied to DLP and LCM as layer-by-layer AM-technologies for bigger parts. Hybridizing both technologies enables ceramic parts with microscopic accuracy at macroscopic dimensions. The feedstock was even applied to the volumetric Xolography with the highest transparency requirement so far and to versatile and flexible holographic AM.
What are the next steps? Can those proof-of -concept studies be transferred to industrial applications and what are the hurdles on the way? How to make the stretch between fundamental research and application-oriented development?
T2 - Smart Made 2025
CY - Osaka, Japan
DA - 01.10.2025
KW - Tranparent
KW - Ceramic
KW - Additive manufacturing
PY - 2025
AN - OPUS4-65062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, Sven
A1 - Pauw, Brian Richard
A1 - Weimann, Christiane
A1 - Sturm, Heinz
T1 - First of its kind: A test artifact for direct laser writing
N2 - With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate the high geometrical resolution of fs-LDW structures and the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement.
KW - Laser direct writing
KW - Multi photon lithography
KW - Reference material
KW - Raman spectroscopy
KW - Confocal raman imaging
KW - Slicers
KW - Open data on zenodo
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580951
DO - https://doi.org/10.1088/1361-6501/acc47a
VL - 34
IS - 7
SP - 1
EP - 14
PB - IOP Science
AN - OPUS4-58095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
ED - Schraut, Katharina
ED - Adamczyk, Burkart
ED - Adam, Christian
ED - Stephan, D.
ED - Simon, Sebastian
ED - von Werder, Julia
ED - Meng, Birgit
T1 - Production of a hydraulic material from post treated steelmaking slags
N2 - Steelmaking slag is a by-product of steel production, of which 4.5 Mt were produced in 2020 in Germany alone. It is mainly used in road construction, earthwork and hydraulic engineering. A smaller part is returned to the metallurgical cycle, used as fertiliser or landfilled.
With this use, iron oxides still contained in steelmaking slag are lost. In addition, the possibility of producing higher-grade products from steelmaking slag is foregone. In recent decades, many researchers have investigated the production of Portland cement clinker and crude iron from basic oxygen furnace slags (BOFS) via a reductive treatment. Carbothermal treatment of liquid BOFS causes a reduction of iron oxides to metallic iron, which separates from the mineral phase due to its higher density. Simultaneously, the chemical composition of the reduced slag is adapted to that of Portland cement clinker.
In this study, German BOFS was reduced in a small-scale electric arc furnace using petrol coke as a reducing agent. The resulting low-iron mineral product has a similar chemical composition to Portland cement clinker and was rich in the tricalcium silicate solid solution alite (Ca3SiO5). Based on its chemical and mineralogical composition, similar to that of Portland cement clinker, the reduced BOFS has the potential to react comparably. In our study, the reduced BOFS produced less hydration heat than OPC, and its hydraulic reaction was delayed. However, adding gypsum has shown to accelerate the hydration rate of the reduced BOFS compared to that known from the calcium silicates of Portland cement clinker.
Further research to improve the hydraulic properties of the reduced slag is essential. If successful, producing a hydraulic binder and crude iron from BOFS has economic and ecological benefits for both the cement and steel industries.
T2 - The 16th International Congress on the Chemistry of Cement 2023 (ICCC2023)
CY - Bangkok, Thailand
DA - 18.09.2023
KW - Steelmaking slag
KW - Alite
KW - Clinker substitute
KW - Hydraulic reactivity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590522
UR - https://www.iccc-online.org/archive/
SP - 432
EP - 436
CY - Bangkok
AN - OPUS4-59052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonneau, Klara
A1 - Lederer, Jonas
A1 - Templeton, Clark
A1 - Giambagli, Lorenzo
A1 - Rosenberger, David
A1 - Müller, Klaus-Robert
A1 - Clementi, Cecilia
T1 - Peering inside the black box by learning the relevance of many-body functions in neural network potentials
N2 - Machine learned potentials based on artificial neural networks are becoming apopular tool to define an effective energy model for complex systems, either incorporating electronic structure effects at the atomistic resolution, or effectively renormalizing part of the atomistic degrees of freedom at a coarsegrained resolution. One main criticism regarding neural network potentials is that their inferred energy is less interpretable than in traditional approaches, which use simpler and more transparent functional forms. Here we address this problem by extending tools recently proposed in the nascent field of explainable artificial intelligence to coarse-grained potentials based on graph neural networks.With these tools, neural network potentials can be practically decomposed into n-body interactions, providing a human understandable interpretation without compromising predictive power. We demonstrate the approach on three different coarse-grained systems including two fluids (methane and water) and the protein NTL9. The obtained interpretations suggest that well-trained neural network potentials learn physical interactions, which are consistent with fundamental principles.
KW - Neural Network
KW - Explainability
KW - Machine learning potentials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647531
DO - https://doi.org/10.1038/s41467-025-65863-0
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 14
AN - OPUS4-64753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falkenberg, Rainer
A1 - Kamachali, Reza Darvishi
T1 - Segregation-induced hydrogen embrittlement in titanium
N2 - Although titanium offers an optimal combination of strength, low weight, and toughness for various applications, it suffers from a drawback: loss of ductility upon exposure to hydrogen. In this work, we couple CALPHAD-integrated density-based thermodynamic modelling of hydrogen segregation with an experimentally calibrated fracture model to investigate its on crack propagation in titanium. Here we propose to model the crack propagation path as a quasi-interface with slightly opened structure and reduced atomic density, enabling interstitial hydrogen segregation. The atomic density is then directly linked with the damage parameter. We found that hydrogen segregation in titanium undergoes a significant transition such that above a threshold of only few atomic percent hydrogen in the solid solution, the interfacial hydrogen concentration exceeds 20 at.%. Integrating this information into our fracture model, the material damage evolution could be explained by a segregation-affected Griffith crack energy, resulting in material decohesion. We found that the segregation transition and subsequent embrittlement effects are critically sensitive to the temperature in the system. The present results suggest a mechanism underlying the sudden loss of fracture toughness during crack propagation, in relation to the ductile-to-brittle transition observed in titanium alloys exposed to hydrogen. The proposed CALPHAD-integrated chemo-mechanical framework can be further generalised for studying more complex failure mechanisms in various materials.
KW - Segregation transition
KW - Hydrogen embrittlement
KW - Titanium alloys
KW - Crack propagation
KW - Ductile-to-brittle transition
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655451
DO - https://doi.org/10.1016/j.mtla.2025.102411
SN - 2589-1529
VL - 41
SP - 1
EP - 12
PB - Elsevier Inc.
AN - OPUS4-65545
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shovo, Redoy Gazi
A1 - Thünemann, Andreas
A1 - Katcharava, Zviadi
A1 - Marinvo, Anja
A1 - Hoppe, Richard
A1 - Woltersdorf, Georg
A1 - Du, Mengxue
A1 - Androsch, Rene
A1 - de Souza e Silva, Juliana Martins
A1 - Busse, Karste
A1 - Binder, Wolfgang H.
T1 - Generating Tagged Micro- and Nanoparticles of Poly(ethylene furanoate) and Poly(ethylene terephthalate) as Reference Materials
N2 - Detecting nanoplastic particles in environmental samples and biological tissues remains a significant challenge, especially in view of newly emerging polymers, not yet commercially exploited. Fluorescent labeling provides a tagging strategy to overcome this limitation by reducing the detection limit of individual particles, especially for small-sized particles. We present a method for producing labeled nanoparticles (NP/MP) of poly(ethylene terephthalate) (PET) and poly(ethylene furanoate) (PEF), tagged with Alexa Fluor 633 or Alexa Fluor 647. Our preparations used mechanical grinding or solvent-based approaches (confined impinging jet mixing, ((CIJ, precipitation), generating particles with hydrodynamic diameters of 200–700 nm, displaying long-term stability in water of up to 57 days. Stable suspensions with concentrations of the particles ranging from 10 µg/mL (surfactant-free, by solvent mixing) to 5.88 mg/mL (precipitation, containing surfactant) were generated with zeta-potentials from −5 to −50 mV. Characterization of the nanoparticles by SEC, DSC, and XRD showed no significant changes in molecular weight, thermal behavior, or crystallinity via the solvent-based methods, compared to the pristine polymer, highlighting their suitability for producing standardized nanoparticle dispersions. Fluorescence spectroscopy of the Alexa-dye-labeled particles confirmed the successful incorporation of the Alexa dyes, so improving monitoring of their biological profiles of the PEF-MP/NPs. s-SNOM (near field imaging) could identify individual PEF-particles sized ∼200 nm by direct imaging.
KW - Reference Materials
KW - Nanoplastics
KW - Microplastics
KW - Polymer
KW - Fluorescence
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655531
DO - https://doi.org/10.1002/marc.202500839
SN - 1521-3927
VL - 47
IS - 4
SP - 1
EP - 11
PB - Wiley VHC-Verlag
CY - Weinheim
AN - OPUS4-65553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Small but Great – Multifunctional Graphene in Rubber Nanocomposites
N2 - A few layer/multilayer graphene (MLG) with a specific surface area of BET ≥ 250 m2/g is proposed as an efficient multifunctional nanofiller for rubbers. The preparation method, i.e., ultrasonically-assisted solution or latex premixing of master batches followed by conventional two-roll milling, strongly influences the dispersion in the elastomeric matrix and is fundamental for the final properties. When homogenously dispersed, single stacks of only approximately 10 graphene sheets, with an aspect ratio of ca. 35, work at low loadings, enabling the replacement of large amounts of carbon black (CB), an increase in efficiency, and a reduction in filler load. The appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing, gas barrier properties, electrical and thermal conductivity, as well as mechanical properties of different rubbers, as shown for chlorine-Isobutylene-Isoprene rubber (CIIR), nitrile-butadiene rubber (NBR), natural rubber (NR), and styrene-butadiene rubber (SBR).[1-5] 3 phr of MLG tripled the Young’s modulus of CIIR, an effect equivalent to 20 phr of CB. The stronger interactions between MLG and NR or SBR also resulted in a reduction in the elongation at break by 20% and 50%, respectively, while the same parameter was hardly changed for CIIR/MLG and NBR/MLG. CIIR/MLG and NBR/MLG were stiffer but just as defomable than CIIR and NBR. The strong reinforcing effect of 3 phr MLG was confirmed by the increase of greater than 10 Shore A in hardness. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards flammability. We investigated MLG also as a synergist for reducing the aluminium trihydrate loading in flame retardant hydrogenated acrylonitrile-butadiene (HNBR), polybutadiene chloroprene (BR/CR), and chlorosulfonated polyethylene rubber(CSM).[6-8] The higher the nanofiller concentration is, the greater the improvement in the properties. For instance, the permeability decreased by 30% at 3 phr of MLG, 50% at 5 phr and 60% at 10 phr, respectively. Moreover, the MLG nanocomposites improve stability of mechanical properties against the effects of weathering. In key experiments an increase in UV-absorption and a pronounced radical scavenging were proved as stabilizing mechanisms. In a nutshell, MLG is an efficient multifunctional nanofiller ready to be used for innovative rubber development.
T2 - 34th PDDG Conference
CY - Dubrovnik, Croatia
DA - 11.06.2023
KW - Graphene
KW - Nanocomposites
KW - Reinforcement
KW - Antioxydant
KW - Flame retardant
KW - Durability
PY - 2023
AN - OPUS4-57693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Structure analysis of dispersible SnO2 nanoparticlesStructure analysis of dispersible SnO2 nanoparticles
N2 - Previous work in the Dunne Group targeted dispersibility of metal oxide nanoparticles, which had been synthesised via an aqueous sol-gel route. Dispersibility was attained by solvothermal surface modification of the particles with trifluoro acetic acid (TFA). Part of the studies were tin oxide particles, which is known for its predominant rutile phase. Besides the dispersibility in acetone of the particles, an unexpected peak splitting of the (110) reflection was observed, which could be an unknown phase of SnO2 . For crystal growth long-term reaction studies on the tin oxide particles were performed. Interestingly these studies exhibited a time dependent extend of the peak splitting observed in XRD characterisation. Further extended analysis using multinuclear solid-state MAS-NMR spectroscopy indicate a size dependent structure change due to partial fluorination of the particles during the solvothermal treatment.
T2 - SALSA Make and Measure 2022
CY - Online meeting
DA - 07.09.2022
KW - SnO2
KW - Nanoparticles
PY - 2022
AN - OPUS4-57201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Dispersible SnO2 nanoparticles - a structural phenomenon
N2 - Previous work in the Dunne Group targeted dispersibility of metal oxide nanoparticles, which had been synthesised via an aqueous sol-gel route. Dispersibility was attained by solvothermal surface modification of the particles with trifluoro acetic acid.
Part of the studies were tin oxide particles, which is known for its predominant rutile phase.
Despite dispersibility in acetone of the particles unexpected peak splitting of the first (110) reflection was observed.
Intensive long-term reaction studies on the tin oxide particles exhibited a time dependent extend of the peak splitting observed in XRD character-isation. Extended characterisation using solid-state multinuclear MAS-NMR spectroscopy indicate size dependent structure change due to partial fluorination of the particles during the solvothermal treatment.
T2 - RSC Twitter Poster Conference 2022
CY - Online meeting
DA - 01.03.2022
KW - SnO2
KW - Nanoparticles
PY - 2022
AN - OPUS4-57225
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - How can ellipsometry help us to understand ultrashort pulse laser material processing?
N2 - Laser processing of materials is a key technology in many fields of modern production. Still, more work is needed to understand the mechanisms behind laser material interaction. Recently, ellipsometry has become a valuable tool for investigating materials pre and post laser irradiation. Imaging ellipsometry and time-resolved methods boost this work and open up the path to a much better understanding of light interaction with solid state surfaces. We use spectroscopic single-spot and imaging ellipsometry to investigate treated and untreated surfaces. The goal is to determine changes in the material dielectric function, as well as geometric changes in surface layers (oxidation, modification, ablation, blistering). A good knowledge of bulk dielectric functions is often needed to model processes caused by laser irradiation. Imaging ellipsometry can play an important role in the post-analysis of laser treated sites on surfaces if combined with other methods such as IR-spectroscopy, SEM, topometric methods, Raman-spectroscopy, and XPS. In this work, we present the results of several studies to investigate laser-treated materials by means of ellipsometry. We cover the following topics:
• Ablation of amorphous carbon layers, role of intra-layer interference effects on the result
• Amorphisation behaviour of c-Si, depending on the crystal orientation,
• Understanding the role of bulk and surface properties on ablation behaviour of classical and
multicomponent high-entropy metals,
T2 - 13th Workshop on Spectroscopic Ellipsometry
CY - Genova, Italy
DA - 09.02.2026
KW - Ellipsometry
KW - Laser Ablation
KW - Femtosecond Technology
KW - Surface and Thin Layer Technology
KW - Laser Surface processing
PY - 2026
AN - OPUS4-65521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pei, R.
A1 - Petrazoller, J.
A1 - Atila, Achraf
A1 - Arnoldi, S.
A1 - Xiao, L.
A1 - Liu, X.
A1 - Wang, H.
A1 - Korte-Kerzel, S.
A1 - Berbenni, S.
A1 - Richeton, T.
A1 - Guénolé, J.
A1 - Xie, Z.
A1 - Al-Samman, T.
T1 - Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study
N2 - Solute segregation at low-angle grain boundaries (LAGBs) critically affects the microstructure and mechanicalproperties of magnesium (Mg) alloys. In modern alloys containing multiple substitutional elements, understanding solute-solute interactions at microstructural defects becomes essential for alloy design. This study investigates the co-segregation mechanisms of calcium (Ca), zinc (Zn), and aluminum (Al) at a LAGB in a dilute Mg-0.23Al-1.00Zn-0.38Ca (AZX010) alloy by combining atomic-scale experimental and modeling techniques.Three-dimensional atom probe tomography (3D-APT) revealed significant segregation of Ca, Zn, and Al at the LAGB, with Ca forming linear segregation patterns along dislocation arrays characteristic of the LAGB. Clustering analysis showed increased Ca–Ca pairs at the boundary, indicating synergistic solute interactions.
Atomistic simulations and elastic dipole calculations demonstrated that larger Ca atoms prefer tensile regions around dislocations, while smaller Zn and Al atoms favor compressive areas. These simulations also found that Ca–Ca co-segregation near dislocation cores is energetically more favorable than other solute pairings, explaining the enhanced Ca clustering observed experimentally. Thermodynamic modeling incorporating calculated segregation energies and solute-solute interactions accurately predicted solute concentrations at the LAGB, aligning with experimental data. The findings emphasize the importance of solute interactionsat dislocation cores in Mg alloys, offering insights for improving mechanical performance through targeted alloying and grain boundary engineering.
KW - Atomic probe tomography
KW - Atomistic simulation
KW - Grain boundary
KW - Co-segregation
KW - Magnesium alloy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655248
DO - https://doi.org/10.1016/j.actamat.2026.121947
SN - 1359-6454
VL - 306
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-65524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
A1 - Treutler, Kai
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Influence of Microstructure on the Machinability and Surface Integrity of Additively Manufactured Iron Aluminides
N2 - The increasing global focus on energy and resource efficiency has stimulated a growing interest in additive manufacturing. AM offers economic advantages and enables an efficient use of materials. However, AM components often require subsequent mechanical post-processing, such as machining (e.g. milling), to achieve the final contours or surfaces. This is a particular challenge due to the heterogeneous and anisotropic nature of AM structures, which affect machining and the resulting component properties. High-performance materials such as iron aluminide represent a promising alternative to conventional high-temperature materials with a significant economic advantage. However, the strength and hardness properties, which are advantageous for applications in highly stressed lightweight components, pose a challenge for economical machining in addition to the AM microstructure properties. The difficult-to-cut material causes accelerated tool wear and insufficient surface quality. This study shows that crack-free additive manufacturing of the three-component system of iron-nickel-aluminum is possible, and advantages in terms of machinability compared to FeAl-AM components are achieved. The more homogeneous microstructure leads to a reduction in cutting forces, with positive effects on the machinability and optimized surface integrity. Ultrasonic assisted milling (USAM) offers great potential to address the major challenges posed by difficult-to-cut materials and additively manufactured weld structures. Therefore, this study focuses on assessing the transferability of previous positive results by USAM to the selected iron aluminide alloys. The machinability of the aluminides is analyzed by varying significant influencing variables in finish milling experiments and evaluated in terms of the loads on the tool and the resulting surface integrity.
T2 - AA Meeting of Commission IX ‘Behavior of Metals subject to Welding’
CY - Rhodes, Greece
DA - 08.07.2024
KW - Iron aluminide
KW - Additive manufacturing
KW - Machinability
KW - Surface integrity
KW - Ultrasonic-assisted milling
PY - 2026
SP - 1
EP - 16
AN - OPUS4-65530
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nicolai, Marcel
T1 - Investigation of lamb wave mode repulsion with a spring-based model
N2 - Lamb waves are widely utilized in material characterization, non-destructive testing (NDT), and structural health monitoring (SHM). A unique feature of Lamb waves is mode repulsion, where dispersion curves approach each other but do not cross. This phenomenon is observed in both single and multilayer plates and is influenced by wave coupling. While mode repulsion in single plates has been linked to symmetry-breaking effects, its underlying mechanism in multilayer systems remains unclear. This study investigates mode repulsion in a coupled aluminum-polycarbonate plate system using a spring-based interface model. Dispersion curves are computed via the Scaled Boundary Finite Element Method, and time-domain simulations are used to analyze the interface dynamics. Results indicate that repulsion depends on interface stiffness, distinguishing between opening and closing repulsion regions. The study further reveals that mode repulsion corresponds to distinct oscillatory behaviors in the interface, where certain wave modes induce increased coupling spring elongation, leading to localized strain. A coupled harmonic oscillator model effectively explains opening repulsion regions but does not fully capture closing regions. Findings suggest that mode repulsion could be leveraged for non-destructive evaluation of adhesive interfaces, offering insights into bond strength characterization. This research contributes to a deeper understanding of wave interactions in multilayer structures and provides a theoretical foundation for advancing NDT and SHM techniques.
T2 - 2025 ICU PADERBORN - 9th International Congress on Ultrasonics
CY - Paderborn, Germany
DA - 21.09.2025
KW - Lamb waves
KW - Mode repulsion
KW - Coupled plates
KW - Elastic interface
KW - Dispersion curves
PY - 2025
AN - OPUS4-65531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Redda, Zinnabu Tassew
A1 - Prinz, Carsten
A1 - Yimam, Abubeker
A1 - Barz, Mirko
A1 - Becker, Katharina
A1 - Gizaw, Desta Getachew
A1 - Laß-Seyoum, Asnakech
T1 - Structural and textural characterization of Brassica carinata biochar to investigate its potential industrial applications
N2 - Biochar, a low-cost, and carbon-rich product of the thermal decomposition of biomass under oxygen-limited conditions and at relatively low temperatures, has recently been identified as a promising porous material with a wide range of industrial applications. In the present study, a comprehensive analysis of proximate, ultimate, nutrient profile, structural, and textural properties of a biochar derived from two Ethiopian indigenous Brassica carinata cultivars was conducted. The characterization of the biochar was achieved by employing a variety of well-established methods, including proximate analysis (moisture, volatile matter, ash content, and fixed carbon), ultimate analysis (C, S, and O content), atomic oxygen to carbon ratio (O/C), morphological and elemental composition analysis through scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). Furthermore, a combination of mercury intrusion porosimetry (MIP), dynamic vapor sorption (DVS), and gas adsorption methods such as nitrogen and krypton gas adsorption, were used for an in-depth study of the porous structure. SEM morphological characterization showed that the biochar surfaces showed multiple pores of diverse sizes and shapes. EDS elemental composition analysis revealed that sodium, aluminium, and silicon were not detected, but potassium, calcium, magnesium, and iron were all present in noticeable amounts. Furthermore, ultimate analysis showed that the most prevalent elements were carbon (86 wt.%) and oxygen (10.41‒9.77 wt.%), while sulphur was present in negligible concentrations. MIP analysis demonstrated that the porosities of the biochars varied from 62.68 to 69.99 wt.%, with the Holetta-1 biochar showing the highest porosity. The superior porosity of Holetta-1, as confirmed via MIP analysis, yielded higher values for bulk volume (2.36 mL g− 1), skeletal volume (1.65 mL g− 1), and total intrusion volume (1.65 mL g− 1) compared to the Yellow Dodolla. The most frequent pore diameters were 172.46 μm for Yellow Dodolla and 111.42 μm for Holetta-1. The MIP log differential pore diameter distributions were observed to vary from 18 to 411 μm and 10 to 411 μm, respectively, for Yellow Dodolla and Holetta-1. Despite the biochars’ low specific surface areas (0.17–0.21 m² g⁻¹), krypton sorption was a suitable technique for its characterization compared to DVS and nitrogen sorption methods. In conclusion, the characterization studies confirmed that this carbon-rich porous material possesses unique and valuable properties, with these attributes position it as a promising alternative for diverse industrial applications, contributing to the development of a bio-based circular economy.
KW - Morphological characterization
KW - Mercury intrusion porosimetry
KW - Gas adsorption
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655325
DO - https://doi.org/10.1038/s41598-025-32063-1
SN - 2045-2322
VL - 16
IS - 1
SP - 1
EP - 19
PB - Springer Science and Business Media LLC
AN - OPUS4-65532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erning, Johann Wilhelm
T1 - Werkstoffe im Kontakt mit Trinkwasser: Von den UBA-Bewertungsgrundlagen nach Europa
N2 - Die Grundlagen der hygienischen Bewertung von Werkstoffen im Kontakt mit Trinkwasser werden erläutert. Die regulatorischen Hintergründe und die Überführung der Regeln in den europäischen rahmen werden diskutiert und an Beispielen erläutert
T2 - Abschlusskonferenz ZEP-Fittings
CY - Lüdenscheid, Germany
DA - 05.02.2026
KW - Korrosion
KW - Trinkwasserhygiene
KW - Europa
KW - Werkstoffe
PY - 2026
AN - OPUS4-65536
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brischke, C.
A1 - Bollmus, S.
A1 - Melcher, E.
A1 - Stephan, Ina
T1 - Biological durability and moisture ynamics of Dawn redwood (Metasequoia glyptostroboides) and Port Orford cedar (Chamaecyparis lawsoniana)
N2 - Numerous non-native tree species are given attention with respect to the reforestation of calamity areas in Europe. Among them, several species may form durable wood which can be used for outdoor applications, but differences in wood durability are expected between original and European growth sites. This study aimed at examining the biological durability against wooddestroying fungi and water permeability of German-grown Dawn redwood (Metasequoia glyptostroboides) and Port Orford cedar (Chamaecyparis lawsoniana). The heartwood of both wood species was assigned to durability class 4 (DC 4, less durable) in soil contact and DC 1–4 (very to less durable) against wood-destroying basidiomycetes. However, according to the Meyer-Veltrup model, their material resistance dose was notably higher compared to the reference species Norway spruce (Picea abies), and the resulting service life of above ground structures should be a multiple of the reference.
KW - Natural durability
KW - Fungal decay
KW - Moisture performance
KW - Permeability
KW - Resistance model
KW - Water uptake
PY - 2022
DO - https://doi.org/10.1080/17480272.2022.2101941
SN - 1748-0272
SP - 1
EP - 11
PB - Taylor & Francis
CY - London
AN - OPUS4-55490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bugel, S.
A1 - Hahnel, M.
A1 - Kunde, T.
A1 - de Sousa Amadeu, Nader
A1 - Sun, Y.
A1 - Spieß, A.
A1 - Beglau, T. H. Y.
A1 - Janiak, C.
A1 - Schmidt, B. M.
T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation
N2 - A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,4′-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,2′,3,3′,5,5′,6,6′-octafluoro-4,4′-biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM.
KW - MOF
KW - Filter
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547632
DO - https://doi.org/10.3390/ma15082807
SN - 1996-1944
VL - 15
IS - 8
SP - 1
EP - 18
PB - MDPI
AN - OPUS4-54763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gerrits, Ruben
A1 - Stepec, Biwen An
A1 - Bäßler, Ralph
A1 - Becker, Roland
A1 - Dimper, Matthias
A1 - Feldmann, Ines
A1 - Goff, Kira L.
A1 - Günster, Jens
A1 - Hofmann, Andrea
A1 - Hesse, René
A1 - Kirstein, Sarah
A1 - Klein, Ulrich
A1 - Mauch, Tatjana
A1 - Neumann-Schaal, Meina
A1 - Özcan Sandikcioglu, Özlem
A1 - Taylor, Nicole M.
A1 - Schumacher, Julia
A1 - Shen, Yin
A1 - Strehlau, Heike
A1 - Weise, Matthias
A1 - Wolf, Jacqueline
A1 - Yurkov, Andrey
A1 - Gieg, Lisa M.
A1 - Gorbushina, Anna
T1 - A 30-year-old diesel tank: Fungal-dominated biofilms cause local corrosion of galvanised steel
N2 - The increased use of biodiesel is expected to lead to more microbial corrosion, fouling and fuel degradation issues. In this context, we have analysed the metal, fuel and microbiology of a fouled diesel tank which had been in service for over 30 years. The fuel itself, a B7 biodiesel blend, was not degraded, and—although no free water phase was visible—contained a water content of ~60 ppm. The microbial community was dominated by the fungus Amorphotheca resinae, which formed thick, patchy biofilms on the tank bottom and walls. The tank sheets, composed of galvanised carbon steel, were locally corroded underneath the biofilms, up to a depth of a third of the sheet thickness. On the biofilm-free surfaces, Zn coatings could still be observed. Taken together, A. resinae was shown to thrive in these water-poor conditions, likely enhancing corrosion through the removal of the protective Zn coatings.
KW - Fungal biofilms
KW - Biodiesel degradation mechanisms
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655014
DO - https://doi.org/10.1038/s41529-025-00731-2
SN - 2397-2106
VL - 10
IS - 1
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65501
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dixneit, J.
A1 - Gibmeier, J.
A1 - Kromm, Arne
A1 - Schubnell, J.
A1 - Lang, F.
A1 - Loebich, F.
A1 - Carl, E.-R.
A1 - Ya, W.
T1 - Residual stress distribution of a large component manufactured by AM-DED-Arc from high-strength weld filler material X90
N2 - Currently, DED-Arc manufactured components are not covered by design guidelines, and design factors such as residual stress factors are not defined for such components. This hinders industrial use, especially for components with a remaining surface waviness required by industry. For the first time the stress state of a high-strength, low-alloy, large-scale DED-Arc component was characterised in the as-built state and after cutting off the component from the substrate plate. Complementary methods of residual stress analyses were applied to gain a holistic insight into the residual stress distributions of a thick-walled part. In the as-built state, direction-dependent and position-dependent tensile residual stresses were found for the component at the level of the yield strength of the part. The additive manufacturing strategy continuous spiral deposition has no significant influence on the residual stresses in bead threshold area compared to the residual stresses of the remaining component. For this case, bead threshold is no structural imperfection. By removing the part from the substrate plate, the residual stresses are significantly redistributed. Tensile residual stresses are then present at a moderate level. Compressive residual stresses were determined in the volume of the deposited material. The general consideration of ‘‘high’’ tensile residual stresses in such thick-walled components is rather conservative. Therefore, design guidelines should take the manufacturing condition into account.
KW - AM-DED-Arc
KW - Residual stress
KW - High strength steel
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655239
DO - https://doi.org/10.1177/03093247251406876
SN - 2041-3130
SP - 1
EP - 18
PB - SAGE
AN - OPUS4-65523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Cong
A1 - Müller, Bernd R.
A1 - Prinz, Carsten
A1 - Stroh, Julia
A1 - Feldmann, Ines
A1 - Bruno, Giovanni
T1 - The correlation between porosity characteristics and the crystallographic texture in extruded stabilized aluminium titanate for diesel particulate filter applications
N2 - Porous ceramic diesel particulate filters (DPFs) are extruded products that possess macroscopic anisotropic mechanical and thermal properties. This anisotropy is caused by both morphological features (mostly the orientation of porosity) and crystallographic texture. We systematically studied those two aspects in two aluminum titanate ceramic materials of different porosity using mercury porosimetry, gas adsorption, electron microscopy, X-ray diffraction, and X-ray refraction radiography. We found that a lower porosity content implies a larger isotropy of both the crystal texture and the porosity orientation. We also found that, analogous to cordierite, crystallites do align with their axis of negative thermal expansion along the extrusion direction. However, unlike what found for cordierite, the aluminium titanate crystallite form is such that a more pronounced (0 0 2) texture along the extrusion direction implies porosity aligned perpendicular to it.
KW - Preferred orientation
KW - X-ray refraction
KW - Pore orientation
KW - Crystal structure
KW - Extrusion
KW - Microstructure-property relations
PY - 2020
DO - https://doi.org/10.1016/j.jeurceramsoc.2019.11.076
SN - 0955-2219
VL - 40
IS - 4
SP - 1592
EP - 1601
PB - Elsevier Ltd.
AN - OPUS4-50325
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Orientation of pore space in diesel particulate filter materials
N2 - Porous ceramic diesel particulate filters (DPFs) are extruded products that possess macroscopic anisotropic mechanical and thermal properties. This anisotropy is caused by both morphologic features (mostly the orientation of porosity) and crystallographic texture. We systematically studied those two aspects in a cordierite and two aluminum titanate (AT) ceramic materials of different porosity using mercury porosimetry, gas adsorption, electron microscopy, X-ray diffraction, and X-ray refraction radiography. We found that a lower porosity in AT content implies a larger isotropy of both the crystal texture and the porous space orientation. We also found that, analogous to cordierite, AT crystallites do align with their axis of negative thermal expansion along the extrusion direction. However, unlike what found for cordierite, the aluminium titanate crystallite form is such that a more pronounced (0 0 2) texture along the extrusion direction implies porosity aligned perpendicular to it.
T2 - 6th Cellular Materials CellMAT 2020
CY - Online meeting
DA - 07.10.2020
KW - Microstructure-property relations
KW - Preferred orientation
KW - X-ray refraction
KW - Pore orientation
KW - Crystal structure
KW - Extrusion
PY - 2020
AN - OPUS4-51451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - EXAFS elucidating local structure of zirconium based aorphous heterogeneous catalysts in C-F bond activation
N2 - Amorphous materials play an important role in C-F bond activation but face the difficulty of limited available structural information by methods such as powder XRD and solid-state MAS NMR spectroscopy especially if the nucleus is not abundant enough. Here, we present heterogeneous catalysts, active in C-F bond activation, where EXAFS allowed specifically elucidating the local structure, which would have not been possible elsewise.
T2 - HZB User Meeing 2023
CY - Berlin, Germany
DA - 22.06.2023
KW - Catalysis
KW - Zirconium
KW - C-F bond activation
PY - 2023
AN - OPUS4-59615
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - An Amorphous Lewis-acidic Zirconium Chloro Fluoride as HF Shuttle: C-F Bond Activation and Formation
N2 - In this work, we successfully synthesized amorphous zirconium chloro fluoride (ZCF), which exhibits medium lewis acidity. In addition to investigating the local coordination sphere around the Zr atoms and the material properties, we were able to establish a catalytic behavior of ZCF in C-F bond activation reactions. We present a heterogeneous catalyst that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
T2 - 23rd International Symposium on Fluorine Chemistry
CY - Quebec City, Canada
DA - 23.07.2023
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
PY - 2023
AN - OPUS4-58053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Zirconium chloro fluoride as catalyst for C-F bond activation and HF transfer of fluoroalkanes
N2 - In this work1, we have successfully synthesised amorphous zirconium chloro fluoride (ZCF), which exhibits medium lewis acidity. In addition to investigating the local coordination sphere around the Zr atoms and the material properties, we were able to establish a catalytic behavior of ZCF in C-F bond activation reactions. We present the first heterogeneous catalyst that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
T2 - RSC Poster 2024
CY - Online meeting
DA - 05.03.2024
KW - ZCF
PY - 2024
AN - OPUS4-59619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Atila, Achraf
A1 - Bakhouch, Yasser
A1 - Xie, Zhuocheng
T1 - Revealing the void-size distribution of silica glass using persistent homology
N2 - Oxide glasses have proven to be useful across a wide range of technological applications. Nevertheless, their medium-range structure has remained elusive. Previous studies focused on ring statistics as a metric of the medium-range structure, but this metric provides an incomplete picture of the glassy structure. Here, we use atomistic simulations and state-of-the-art topological analysis tools, namely persistent homology (PH), to analyze the medium-range structure of the archetypal oxide glass (Silica) at ambient temperatures and with varying pressures. PH presents an unbiased definition of loops and voids, providing an advantage over other methods for studying the structure and topology of complex materials, such as glasses, across multiple length scales. We captured subtle topological transitions in medium-range order and cavity distributions, providing new insights into glass structure. Our work provides a robust way for extracting the void distribution of oxide glasses based on PH.
KW - Medium-range
KW - Voids
KW - Topology
KW - Silica glass
KW - Atomistic simulations
KW - Persistent homology
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655690
DO - https://doi.org/10.1016/j.mtla.2025.102613
VL - 44
SP - 1
EP - 11
PB - Elsevier Inc.
AN - OPUS4-65569
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shaikh, Abdul Shaafi
A1 - Fardan, Ahmed
A1 - Mishurova, Tatiana
A1 - Hryha, Eduard
T1 - The Impact of High‐Productivity Processing on the Fatigue Failure of an Additive Manufactured Superalloy HAYNES 282
N2 - The elevated temperature low cycle fatigue life of additively manufactured HAYNES 282 superalloy from conventional 40 µm layer thickness process parameters was compared with that of high‐productivity 80 µm layer thickness process parameters. Wrought 282 alloy was also tested in parallel for comparison. The 40 µm process parameters produced fatigue life between 1400 and 1700 cycles to failure, the 80 µm process parameter specimens failed after ≈1200 cycles, and the wrought alloy reached 1350 cycles to failure. Microstructure investigations did not reveal systematic differences in phase constituents or grain structure between 40 and 80 µm processed 282 alloy. While both process parameters produced porosity of less than 0.05% by volume, high‐resolution X‐ray computed tomography showed the occurrence of large aspect ratio lack of fusion defects in the 80 µm material. These defects were also identified on fracture surfaces and could be related to the accelerated initiation and propagation of cracks, especially when oriented perpendicular to the load axis in samples built parallel to the building direction. The results emphasize the criticality of seemingly minor variations in defect characteristics on performance in cyclic loading conditions for high strength alloys.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - PBF-LB
KW - Fatigue
KW - EBSD
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655732
DO - https://doi.org/10.1002/adem.202502048
SN - 1438-1656
SP - 1
EP - 13
PB - Wiley-VCH GmbH
AN - OPUS4-65573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tiwari, Jitendar Kumar
A1 - Malladi, Bala
A1 - Mishurova, Tatiana
A1 - Fritsch, Tobias
A1 - Nyborg, Lars
A1 - Cao, Yu
T1 - Influence of contour parameters on the surface roughness of fine channels produced by powder bed fusion-laser beam
N2 - Surface roughness strongly influences the performance of fine internal channels in additively manufactured components. This study investigates how contour process parameters affect the surface finish of 1 mm-diameter channels produced by powder bed fusion–laser beam (PBF-LB). Five contour parameter sets with progressively increasing laser energy density (LED) were applied, while keeping infill parameters constant. Surface roughness was evaluated using surface profilometry, X-ray computed tomography (XCT), and optical microscopy (OM). Profilometry and OM provided localized measurements, whereas XCT captured full-channel roughness along the build direction. Results show that increasing LED initially reduces surface roughness due to improved melting and removal of partially fused particles, reaching optimal smoothness at an intermediate LED. Further LED increase causes roughness to rise again, attributed to balling and dross formation. Optical cross-sections depicted these trends, and XCT measurements closely matched profilometry data. The findings in this study highlight a trade-off between surface quality and dimensional accuracy, as higher LEDs improve smoothness but reduce channel diameter. This work establishes an optimal contour LED range for minimizing as-built surface roughness in fine internal channels, which can enhance the functional performance of PBF-LB components in aerospace, medical, and energy applications.
KW - Additive manufacturing
KW - PBF-LB
KW - Surface roughness
KW - Computed tomography
KW - Optical tomography
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655677
DO - https://doi.org/10.1016/j.vacuum.2026.115085
SN - 0042-207X
VL - 246
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-65567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - How to get it right with photoluminescence measurements in the UV/VIS/NIR
N2 - Optical measurements of transparent solutions of organic dyes and semiconductor quantum dots and scattering materials such as luminescent nanocomposites and microparticles and phosphors dispersed in liquid and solid matrices play an important role in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. A key performance parameter is the photoluminescence quantum yield QY, i.e., the number of emitted per number of absorbed photons. QY of transparent luminophore solutions can be obtained relative to a fluorescence QY standard of known QY. Such relative QY measurements require a calibrated spectrofluorometer. Here, we address typical sources of uncertainty for luminescence measurements and relative and absolute QY measurements from the instrument and material side and provide recommendations to circumvent or at least minimize them for transparent and scattering samples in the UV/vis/NIR/SWIR.
T2 - Workshop "Photoluminescence Spectroscopy and its application in Materials Research"
CY - Vienna, Austria
DA - 19.02.2026
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2026
AN - OPUS4-65575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Digital Transformation in Materials Science: PMD Core Ontology (PMDco) 3.0 – Patterns & Applications
N2 - The digitalization of Materials Science and Engineering (MSE) demands standardized, interoperable approaches for representing complex experimental and simulation data. To address this challenge, the Platform MaterialDigital Core Ontology (PMDco) provides a mid-level semantic framework that bridges high-level ontologies and domain-specific terminologies. PMDco version 3.0, recently released, introduces significant enhancements based on a full alignment with the Basic Formal Ontology (BFO) as standardized in ISO/IEC 21838-2. This alignment ensures conceptual consistency and facilitates integration across heterogeneous data sources while enabling FAIR-compliant workflows.
First addressing the idea behind a mid-level ontology in MSE, this presentation emphasizes its role in harmonizing diverse data models and supporting machine-actionable knowledge representation. New features and design patterns introduced in PMDco 3.0 will be highlighted, which strengthen interoperability and provide reusable modeling structures for common MSE concepts. Practical applications and prototype implementations will be discussed.
PMDco has been developed through active community involvement and its future evolution relies on continued collaboration and discussion within the MSE community. Participation is strongly encouraged to ensure that PMDco remains relevant, comprehensive, and widely adopted. More information and opportunities to contribute can be found at materialdigital.de and github.com/materialdigital/core-ontology.
T2 - VMAP User Forum 2026
CY - Sankt Augustin, Germany
DA - 24.02.2026
KW - Semantic Technology
KW - Knowledge Graph
KW - PMD Core Ontology
KW - Semantic Pattern
KW - Machine-actionability
PY - 2026
AN - OPUS4-65574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Do Microbes like Additively Manufactured Aluminium?
N2 - The use of laser-additively manufactured metallic components in the industrial sector is gaining traction, with the process now entering its application phase. Consequently, the materials are exposed to corrosive microbes, which this study examines in order to determine the implications of this exposure. Specifically, the study examines the exposure of laser powder bed fused AlSi10Mg (PBF-LB/AlSi10Mg) components to sulphate-reducing bacteria in an anaerobic environment. Is the specific PBF-LB microstructure a potential factor in determining or aiding biocorrosion?
A prismatic specimen was exposed to sulphate-reducing bacteria (SRB) for two weeks. The sample was scanned by X-ray computed tomography (XCT) before and after SRB exposure. The two data sets were registered to each other (using the internal void distribution as markers, due to the corrosion of the specimen’s surface) to enable the evaluation of the corrosion damage.
Virtual cuts of the 3D XCT reconstructions show a loss of volume and localised damage. The damage distribution aligns with the hatching pattern of laser exposure from laser powder bed fusion.
T2 - Konferenz iCT 2026
CY - Linz, Austria
DA - 10.02.2026
KW - Computed tomography
KW - Biokorrosion
KW - Additive manufacturing
KW - PBF-LB
KW - Laser powder bed fusion
KW - Sulphate-reducing bacteria
PY - 2026
AN - OPUS4-65570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
T1 - Herausforderungen und Potenziale moderner Hochleistungs-Lichtbogenprozesse für effiziente Reparaturmaßnahmen an Altstahlkonstruktionen
N2 - Stahltragwerke, die im späten 19. und frühen 20. Jahrhundert errichtet wurden, stellen noch heute einen wesentlichen Bestandteil der technischen Infrastruktur dar. Ein erheblicher Anteil der Brücken- und Ingenieurbauwerke befindet sich seit mehr als 80 oder sogar 100 Jahren in Betrieb und ist kontinuierlich steigenden Verkehrsaufkommen, Achslasten sowie dynamischen Einwirkungen ausgesetzt. Vor dem Hintergrund dieser zunehmenden Beanspruchungen sind beanspruchungsgerechte und konstruktiv angemessene Instandsetzungsstrategien unerlässlich, um die langfristige strukturelle Integrität sicherzustellen und zugleich den vorhandenen Baubestand nachhaltig zu erhalten.
Da historische Stahlkonstruktionen überwiegend für genietete oder geschraubte Verbindungen ausgelegt wurden, stellt die nachträgliche Umsetzung geschweißter Reparatur- oder Verstärkungsmaßnahmen eine besondere Herausforderung dar. Neben den spezifischen werkstofflichen Eigenschaften alter Flussstähle sind insbesondere schweißbedingte Eigenspannungen sowie mikrostrukturelle Veränderungen zu berücksichtigen, da diese die Tragfähigkeit und das Gesamttragverhalten maßgeblich beeinflussen können. Infolgedessen müssen Instandsetzungskonzepte nicht nur die geometrische Wiederherstellung gewährleisten, sondern zugleich an den tatsächlichen Spannungszustand und die betrieblichen Beanspruchungen des Tragwerks angepasst werden.
Vor diesem Hintergrund untersucht die vorliegende Arbeit MAG-Schweißversuche an Mischverbindungen zwischen historischem und modernem Baustahl. Der Nahtöffnungswinkel wurde systematisch zwischen 50° und 30° variiert, um den Einfluss der Fugengeometrie auf das Schweißgutvolumen, die Wärmeeinbringung sowie den resultierenden Eigenspannungszustand zu analysieren. Darüber hinaus kamen innovative Hochleistungs-Lichtbogenprozesse, wie beispielsweise ein modifizierter Sprühlichtbogen, zum Einsatz, um eine kontrollierte und reduzierte Wärmeeinbringung zu ermöglichen. Ziel ist es, schweißbedingte Eigenspannungen durch eine Optimierung von Prozessführung und Fugengestaltung zu minimieren und damit eine technisch fundierte sowie beanspruchungsgerechte Instandsetzungsstrategie für bestehende historische Stahltragwerke mit langfristiger Gebrauchstauglichkeit bereitzustellen.
T2 - Forschungsseminar an der OvGU Magdeburg
CY - Magdeburg, Germany
DA - 18.02.2026
KW - Flussstahl
KW - Reparaturmaßnahmen
KW - Schweißeignung
KW - Modifizierter Sprühlichtbogen
KW - Eigenspannungen
PY - 2026
AN - OPUS4-65577
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eddah, Mustapha
A1 - Markötter, Henning
A1 - Mieller, Björn
A1 - Widjaja, Martinus Putra
A1 - Beckmann, Jörg
A1 - Bruno, Giovanni
T1 - Multi-Energy High Dynamic Range (HDR) Synchrotron X-ray Computed Tomography applied to LTCC samples
N2 - Synchrotron X-ray computed tomography (SXCT) is regularly used in materials science to correlate structural properties with macroscopic properties and to optimize manufacturing processes. The X-ray beam energy must be adapted to the sample properties, such as size and density. If both strongly and weakly absorbing materials are present, the contrast to the weakly absorbing materials is lost, resulting in image artifacts and a poor signal-to-noise ratio (SNR). One example is a low-temperature co-fired ceramics (LTCC), in which metal connections are embedded in a ceramic matrix and form 3-dimensional conducting structures. This article describes a method of combining SXCT scans acquired at different beam energies, significantly reducing metal artifacts, and improving image quality. We show how to solve the difficult task of merging the scans at low and high beam energy. Our proposed merging approach achieves up to 35% improvement in SNR within ceramic regions adjacent to metallic conductors. In this way, previously inaccessible regions within the ceramic structure close to the metallic conductors are made accessible. The paper further discusses methodological requirements, limitations, and potential extensions of the presented multienergy SXCT merging technique.
T2 - iCT 2026
CY - Linz, Austria
DA - 10.02.2026
KW - Synchrotron x-ray CT
KW - Multi-energy CT
KW - Low-Temperature cofired ceramics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655848
SP - 1
EP - 7
CY - e-Journal of Nondestructive Testing
AN - OPUS4-65584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachet, G.
A1 - Wei, S.
A1 - Tehranchi, Ali
A1 - Dong, X.
A1 - Lestang, J.
A1 - Zhang, A.
A1 - Sun, B.
A1 - Zaefferer, S.
A1 - Gault, B.
A1 - Ponge, D.
A1 - Raabe, D.
ED - Tehranchi, Ali
T1 - Protection of metal interfaces against hydrogen-assisted cracking
N2 - Enabling a hydrogen economy requires the development of materials resistant to hydrogen embrittlement (HE). More than 100 years of research have led to several mechanisms and models describing how hydrogen interacts with lattice defects and leads to mechanical property degradation. However, solutions to protect materials from hydrogen are still scarce. Here, we investigate the role of interstitial solutes in protecting critical crystalline defects sensitive to hydrogen. Ab initio calculations show that boron and carbon in solid solutions at grain boundaries can efficiently prevent hydrogen segregation. We then realized this interface protection concept on martensitic steel, a material strongly prone to HE, by doping the most sensitive interfaces with different concentrations of boron and carbon. These segregations, in addition to stress relaxations, critically reduce the hydrogen ingress by half, leading to an unprecedented resistance against HE. This tailored interstitial segregation strategy can be extended to other metallic materials susceptible to hydrogen-induced interfacial failure.
KW - Hydrogen embrittlement
KW - interstitial
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650881
DO - https://doi.org/10.1038/s41467-025-67310-6
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-65088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fortini, Renata
A1 - Meyer-Plath, A.
A1 - Kehren, D.
A1 - Gernert, U.
A1 - Agudo Jácome, Leonardo
A1 - Sturm, Heinz
T1 - Measurement of flexural rigidity of multi-walled carbon nanotubes by Dynamic Scanning Electron Microscopy
N2 - In this work the flexural rigidity of individual large diameter multi-walled carbon nanotubes (MWCNTs) was investigated. The bending modulus were obtained by detecting the resonance frequencies of mechanically excited cantilevered carbon nanotubes using the so-called dynamic scanning electron microscopy technique, and applying the Euler–Bernoulli beam theory. For the nanotubes studied, we determined a modulus of up to 160 GPa. This agrees with values reported by other authors for MWCNTs produced by catalytic chemical vapor deposition, however, it is 6-8 times smaller than values reported for single and multi-walled carbon nanotubes produced by arc-discharge synthesis. Toxicological studies with carbon nanotubes have been showing that inhaled airborne nanofibers that reach the deep airways of the respiratory system may lead to serious, asbestos-like lung diseases. These studies suggested that their toxicity critically depends on the fiber flexural rigidity, with high rigidity causing cell lesions. To complement the correlation between observed toxicological effects and fiber rigidities, reliable and routinely applicable measurement techniques for the flexural rigidity of nanofibers are required.
KW - Flexural rigidity
KW - Bending modulus
KW - Resonance frequency
KW - Carbon nanotubes
KW - Fiber toxicology
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514190
DO - https://doi.org/10.3390/fib8050031
SN - 2079-6439
VL - 8
IS - 5
SP - 31
PB - MDPI
AN - OPUS4-51419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cano Murillo, Natalia
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Hahn, Marc Benjamin
A1 - Hodoroaba, Vasile-Dan
A1 - Sturm, Heinz
T1 - Nanomechanical study of polycarbonate/boehmite nanoparticles/epoxy ternary composite and their interphases
N2 - Thermoplastic modified thermosets are of great interest especially due to their improved fracture toughness. Comparable enhancements have been achieved by adding different nanofillers including inorganic particles such as nanosized boehmite. Here, we present a nanomechanical study of two composite systems, the first comprising a polycarbonate (PC) layer in contact with epoxy resin (EP) and the second consisting of a PC layer containing boehmite nanoparticles (BNP) which is also in contact with an EP layer. The interaction between PC and EP monomer is tested by in situ Fourier transformed infrared (FT-IR) analysis, from which a reaction induced phase separation of the PC phase is inferred. Both systems are explored by atomic force microscopy (AFM) force spectroscopy. AFM force-distance curves (FDC) show no alteration of the mechanical properties of EP at the interface to PC. However, when a PC phase loaded with BNP is put in contact with an epoxy system during curing, a considerable mechanical improvement exceeding the rule of mixture was detected.
The trend of BNP to agglomerate preferentially around EP dominated regions and the stiffening effect of BNP on EP shown by spatial resolved measurements of Young's modulus, suggest the effective presence of BNP within the EP phase.
KW - Composites
KW - Mechanical properties
KW - Nanoparticles
KW - Thermoplastics
KW - Thermosets
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515965
DO - https://doi.org/10.1002/app.50231
SN - 0021-8995
SN - 1097-4628
VL - 138
IS - 12
SP - 1
EP - 11
PB - Wiley
CY - New York, NY
AN - OPUS4-51596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna Christiane
A1 - Pauw, Brian Richard
A1 - Sturm, Heinz
A1 - Günster, Jens
T1 - First time additively manufactured advanced ceramics by using two-photon polymerization for powder processing
N2 - Methods and materials are presented here, which enable the manufacturing of fine structures using a 3D-printing method known as two-photon polymerization (2PP). As traditional photolithography methods for structuring ceramic slurries do not function with 2PP, due to light scattering on ceramic particles, a novel water-based photoresist with high ceramic loading of extremely well dispersed ceramic nano particles was developed. This photoresist is basically a ceramic slurry containing a photocurable agent and a photoinitiator to be crosslinkable with the 780 nm wavelength femtosecond laser light source of the 2PP machine. It is demonstrated that it is possible to gain a highly transparent and low viscous slurry suitable for 2PP processing. This work shows the development of the slurry, first printing results and the post-printing processes required to form three dimensional ceramic microstructures consisting of alumina toughened zirconia (ATZ).
KW - 3D-printing
KW - Two-photon polymerization
KW - 2PP
KW - Ceramic nano particles
KW - Slurry
KW - Alumina toughened zirconia
KW - ATZ
KW - Additive manufacturing
KW - SchwarzP cells
KW - Nano-ceramic-additive-manufacturing photoresin
KW - NanoCAM
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517441
DO - https://doi.org/10.1016/j.oceram.2020.100040
VL - 4
SP - 100040
PB - Elsevier Ltd.
AN - OPUS4-51744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cano Murillo, Natalia
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Emamverdi, Farnaz
A1 - Cacua, K.
A1 - Hodoroaba, Vasile-Dan
A1 - Sturm, Heinz
T1 - Carrier Fibers for the Safe Dosage of Nanoparticles in Nanocomposites: Nanomechanical and Thermomechanical Study on Polycarbonate/Boehmite Electrospun Fibers Embedded in Epoxy Resin
N2 - The reinforcing effect of boehmite nanoparticles (BNP) in epoxy resins for fiber composite lightweight construction is related to the formation of a soft but bound interphase between filler and polymer. The interphase is able to dissipate crack propagation energy and consequently increases the fracture toughness of the epoxy resin. Usually, the nanoparticles are dispersed in the resin and then mixed with the hardener to form an applicable mixture to impregnate the fibers. If one wishes to locally increase the fracture toughness at particularly stressed positions of the fiber-reinforced polymer composites (FRPC), this could be done by spraying nanoparticles from a suspension. However, this would entail high costs for removing the nanoparticles from the ambient air. We propose that a fiber fleece containing bound nanoparticles be inserted at exposed locations. For the present proof-of-concept study, an electrospun polycarbonate nonwoven and taurine modified BNP are proposed. After fabrication of suitable PC/EP/BNP composites, the thermomechanical properties were tested by dynamic mechanical analysis (DMA). Comparatively, the local nanomechanical properties such as stiffness and elastic modulus were determined by atomic force microscopy (AFM). An additional investigation of the distribution of the nanoparticles in the epoxy matrix, which is a prerequisite for an effective nanocomposite, is carried out by scanning electron microscopy in transmission mode (TSEM). From the results it can be concluded that the concept of carrier fibers for nanoparticles is viable.
KW - Advanced materials
KW - Electrospun nanocomposite fiber
KW - Nanomechanical charecteisation
KW - Nanosafety
KW - Epoxy nanocomposites
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528265
DO - https://doi.org/10.3390/nano11061591
VL - 11
IS - 6
SP - 1591
PB - MDPI
CY - CH - 4020 Basel, Switzerland
AN - OPUS4-52826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schraut, Katharina
A1 - Kargl, F.
A1 - Adam, Christian
A1 - Ivashko, O.
T1 - In situ synchrotron XRD measurements during solidification of a melt in the CaO–SiO2 system using an aerodynamic levitation system
N2 - Phase formation and evolution was investigated in the CaO–SiO2 system in the range of 70–80 mol% CaO. The samples were container-less processed in an aerodynamic levitation system and crystallization was followed in situ by synchrotron x-ray diffraction at the beamline P21.1 at the German electron synchrotron (DESY). Modification changes of di- and tricalcium silicate were observed and occurred at lower temperatures than under equilibrium conditions. Despite deep sample undercooling, no metastable phase formation was observed within the measurement timescale of 1 s. For the given cooling rates ranging from 300 K s−1 to about 1 K s−1, no decomposition of tricalcium silicate was observed. No differences in phase evolution were observed between reducing and oxidizing conditions imposed by the levitation gas (Ar and Ar + O2). We demonstrate that this setup has great potential to follow crystallization in refractory oxide liquids in situ. For sub-second primary phase formation faster detection and for polymorph detection adjustments in resolution have to be implemented.
KW - Aerodynamic levitation
KW - Calcium silicate
KW - Phase formation
KW - Oxide melts
KW - In situ synchrotron x-ray diffraction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526952
DO - https://doi.org/10.1088/1361-648X/abf7e1
VL - 33
IS - 26
SP - 264003 (12pp)
PB - IOP Publishing
AN - OPUS4-52695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Usmani, S.
A1 - Voss, L.
A1 - Stephan, Ina
A1 - Hübert, Thomas
A1 - Kemnitz, E.
T1 - Improved Durability of Wood Treated with Nano Metal Fluorides against Brown-Rot and White-Rot Fungi
N2 - Low-water soluble metal fluorides such as magnesium fluoride (MgF2) and calcium Fluoride (CaF2) were evaluated for decay protection of wood. Initially, the biocidal efficacy of nano metal fluorides (NMFs) against wood destroying fungi was assessed with an in-vitro agar test. The results from the test showed that agar medium containing MgF2 and CaF2 was more efficient in preventing fungal decay than stand-alone MgF2 or CaF2. These metal fluorides, in their nanoscopic form synthesized using fluorolytic sol-gel synthesis, were introduced into the sapwood of Scots pine and beech wood and then subjected to accelerated ageing by leaching (EN 84). MAS 19F NMR and X-ray micro CT images showed that metal fluorides were present in treated wood, unleached and leached. Decay resistance of Scots pine and beech wood treated with NMFs was tested against Wood destroying fungi Rhodonia placenta and Trametes versicolor in accordance with EN 113. Results revealed that mass losses were reduced to below 3% in wood treated with the combination of MgF2 and CaF2.
It is concluded that NMFs provide full protection to wood even after it has been leached and can be used as wood preservatives in outdoor environments.
KW - Nanoparticles
KW - Fluoride
KW - Wood protection
KW - Fluorolytic sol-gel synthesis
KW - Brown-rot fungi
KW - White-rot fungi
KW - Basidiomycetes
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543877
DO - https://doi.org/10.3390/app12031727
VL - 12
IS - 3
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-54387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, Sven
A1 - Topolniak, Ievgeniia
A1 - Weise, Matthias
A1 - Sturm, Heinz
T1 - Shape deviations of DLW microstructures in dependency of fabrication parameters
N2 - Deep understanding of the effects associated with fabrication parameters and their influence on the resulting structures shape is essential for the further development of direct laser writing (DLW). In particular, it is critical for development of reference materials, where structure parameters are precisely fabricated and should be reproduced with use of DLW technology. In this study we investigated the effect of various fabrication and preparation parameters on the structural precision of interest for reference materials. A well-studied photo-curable system, SZ2080 negative photo-resist with 1 wt.% Michler's ketone (Bis) photo-initiator, was investigated in this work. The correlation between applied laser power, laser velocity, fabrication direction on the deviations in the structure shape were observed by means of white light interferometry microscopy. Moreover, influence of slicing and hatching distances as well as prebake time were studied as function of sample shape. Deviations in the structure form between the theoretically expected and the one detected after DLW fabrication were observed in the range up to 15%. The observed shape discrepancies show the essential importance of fine-tuning the fabrication parameter for reference structure production.
KW - Direct laser writing
KW - Fabrication parameters
KW - Structural precision
KW - SZ2080 negative photo-resist
KW - White light interferometry microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535906
DO - https://doi.org/10.1088/1361-6439/ac2a14
VL - 31
IS - 12
SP - 1
EP - 8
PB - IOP Science
AN - OPUS4-53590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lackmann, C.
A1 - Velki, M.
A1 - Šimić, A.
A1 - Müller, Axel
A1 - Braun, U.
A1 - Ečimović, S.
A1 - Hollert, H.
T1 - Two types of microplastics (polystyrene-HBCD and car tire abrasion) affect oxidative stress-related biomarkers in earthworm Eisenia andrei in a time-dependent manner
N2 - Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology.
Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28 d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28 d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28 d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms.
KW - Microplastics
KW - Earthworms
KW - Toxicity
KW - Biomarker
KW - oxidative stress
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545423
DO - https://doi.org/10.1016/j.envint.2022.107190
VL - 163
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-54542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Fritzsche, Sven
A1 - Pauw, Brian Richard
A1 - Weimann, Christiane
A1 - Sturm, Heinz
T1 - First of its kind: A test artifact for direct laser writing
N2 - With Direct Laser Writing (DLW) maturing in all aspects as a manufacturing technology a toolset for quality assurance must be developed. In this work we want to introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric feature to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. Selective Laser Melting. The test artifact introduced in this work was developed in particular to accommodate 1) the high geometrical resolution of DLW structures and 2) the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our DLW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresist, laser power and scanning speed and to analyse the geometric accuracy of a structure produced using these guidelines.
KW - Multi photon lithography
KW - Test artifact
KW - Two photon polymerization
KW - Direct Laser Writing
KW - Quality infrastructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560530
DO - https://doi.org/10.20944/preprints202210.0259.v1
SP - 1
EP - 29
PB - MDPI
CY - Basel
AN - OPUS4-56053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
A1 - Plajer, A. J.
T1 - Thioanhydride/isothiocyanate/epoxide ring-opening terpolymerisation: sequence selective enchainment of monomer mixtures and switchable catalysis
N2 - We report a new sequence selective terpolymerisation in which three monomers (butylene oxide (BO) A, PhNCS B and phtalic thioanhydride (PTA) C) are selectively enchained into an (ABA′C)n sequence. PTA/PhNCS/BO ring-opening terpolymerisation ROTERP can be coupled with CS2 ROTERP to generate tetrapolymers and with εDL ROP in switchable catalysis for blockpolymer synthesis.
KW - Blockcopolymer
KW - 1H-NMR
KW - TGA
KW - DSC
KW - AFM
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552339
DO - https://doi.org/10.1039/d2py00629d
SP - 1
EP - 5
PB - Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-55233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Schutter, Jan David
A1 - Wagner, R.
A1 - Dimper, Matthias
A1 - Lützenkirchen-Hecht, D.
A1 - Özcan Sandikcioglu, Özlem
T1 - Abundance of Fe(III) during cultivation affects the microbiologically influenced corrosion (MIC) behaviour of iron reducing bacteria Shewanella putrefaciens
N2 - The effect of the presence of Fe(III) during the cultivation on the electrochemical activity and corrosion behaviour of dissimilatory iron reducing bacteria Shewanella putrefaciens was studied by means of ex situ and in situ X-ray absorption near-edge spectroscopy (XANES). Stainless steel AISI 304 and thin iron films were studied as substrates. XANES analysis indicated an accelerated iron dissolution and growth of an oxide/hydroxide film for the culture grown with Fe(III) in comparison to the culture grown in absence of Fe(III). Electrochemical Analysis indicated that the biofilm resulted in acceleration of the general corrosion but provides protection against local corrosion.
KW - Stainless Steel
KW - XANES
KW - Iron
KW - Cyclic Voltammetry
KW - Microbiological Corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513788
DO - https://doi.org/10.1016/j.corsci.2020.108855
VL - 174
SP - 108855
PB - Elsevier Ltd.
AN - OPUS4-51378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Processing and application properties of multiple principal element alloys (MPEA)
N2 - The presentation gives an overview of BAM's activities on processing influences and application properties of MPEAs in the form of joined and machined high and medium entropy alloys (CoCrFeMnNi and CoCrNi). In the case of welding, the focus is on defect-free welded joints with sufficient mechanical properties. In the case of machining, the focus is on the possible influence on the surface quality of the materials through adequate milling parameters. In addition, the hydrogen absorption and diffusion properties as well as the electrochemical corrosion behavior are fundamentally examined.
T2 - FAU-Department Werkstoffwissenschaften, Seminar: Aktuelle Probleme der Werkstoffwissenschaften
CY - Erlangen, Germany
DA - 25.04.2024
KW - Welding
KW - Application properties
KW - Machining
KW - High-entropy alloy
KW - Hydrogen
PY - 2024
AN - OPUS4-59975
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Özcan Sandikcioglu, Özlem
T1 - High-throughput, automated and autonomous approaches for the design of corrosion resistant materials
N2 - The integration of high-throughput electrochemistry, experimental automation and AI-driven processes is enabling the rapid discovery and optimization of advanced materials. This presentation will summarize our research in this field.
T2 - GfKORR Grundlagen und Simulation Arbeitsgruppentreffen
CY - Online meeting
DA - 04.07.2024
KW - MAPs@BAM
KW - CCMat
KW - Corrosion
KW - Electrochemistry
PY - 2024
AN - OPUS4-62644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rütters, R.
T1 - Towards defining reasonable minimum composition thresholds – impacts of variable CO2 stream compositions on transport, injection and storage
N2 - The collaborative project “Impacts of impurities in CO2 streams captured from different emitters in a regional cluster on transport, injection and storage (CLUSTER)” aimed to set up recommendations on how to define “reasonable minimum composition thresholds” that CO2 streams should meet when accessing CO2 transport pipeline networks. Within CLUSTER, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the whole CCS chain. Investigations included, amongst others, impacts on: Corrosion of pipeline steel, pipeline network design and related transport costs, alteration of well bore cements, pressure evelopment and rock integrity, geochemical reactions, and petrophysical and geomechanical rock properties.
All investigations are based on a generic CCS chain scenario. In this scenario, CO2 streams are captured from a spatial cluster of eleven emitters and collected in a regional pipeline network. Emitters comprise seven fossil fuel-fired power plants equipped with different capture technologies, two cement plants, one refinery and one integrated iron and steel plant. In total, 19.78 Mio t CO2 (including impurities) are captured in the emitter cluster annually. The combined CO2 stream is transported in a trunk line with a length of 400 km (100 km of these offshore) and is injected into five generic storage structures. The storage reservoirs are saline aquifers of the Buntsandstein.
The investigations revealed beneficial and deteriorating impacts of different impurities and combinations thereof. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the modelled variable compositions and mass flow rates were observed. Based on the results, the CLUSTER project team recommends not to define “minimum composition thresholds” for CO2 streams as strict threshold values for eachindividual impurity in the stream. Instead, CO2 stream compositions and variabilities for specific CCS projects should be constrained with regard to a set of parameters including i) the overall CO2 content, ii) maximum contents of relevant impurities or elements, iii) acceptable variability of CO2 stream composition, and iv)impurity combinations to be avoided.
T2 - 15th International Conference on Greenhouse Gas Control Technologies, GHGT-15
CY - Online meeting
DA - 15.03.2021
KW - Corrosion
KW - Impurities
KW - CO2 quality
KW - Pipeline network
KW - Whole-chain CCS scenario
KW - Recommendations
PY - 2021
AN - OPUS4-52419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Weise, Frank
A1 - Rieffel, Y.
A1 - Gorbushina, Anna
T1 - Die Schlossbrücke Berlin - Schutz der Göttinnen
N2 - Vielleicht nannten es die Berliner „Puppen putzen“, wenn in den 1880er Jahren die Marmorstatuen auf der Schlossbrücke vor dem Berliner Stadtschloss mit Bürste, Wasser und Seife von Staub, Ruß und Taubendreck befreit wurden. Soviel Pflege wurde diesen Göttinnen aus der griechischen Mythologie nicht immer zuteil. So haben Klima, Luftverschmutzung und der 2. Weltkrieg, wie bei anderen Kunstwerken auch, tiefe Spuren hinterlassen. Der Erhalt dieser zwischen 1847 und 1857 aufgestellten Skulpturen und vieler vergleichbarer Objekte im Stadtbild ist durch die auch heute weiter fortschreitende Schädigung des Marmors gefährdet. In den Jahren 2006 bis 2010 förderte die Deutsche Bundesstiftung Umwelt (DBU) ein Projekt zur „Entwicklung und Überprüfung von Einhausungssystemen zur Reduzierung umweltbedingter Schädigungen von außenexponierten Marmorobjekten mit dem Ziel des langfristigen Erhalts in situ an einem national bedeutenden Objektkomplex, den Schlossbrückenfiguren unter den Linden, Berlin“. Geleitet und restauratorisch betreut wurde das Projekt durch das Landesdenkmalamt (LDA) Berlin. Durch die Abteilung Strukturgeologie und Geodynamik (GZG) der Georg-August Universität Göttinnen wurden die Verwitterungsmechanismen des Marmors untersucht und auf dieser Basis Anforderungen an das Schutzsystem formuliert. Anhand von numerischen Simulationen des Instituts für Bauklimatik der Technischen Universität Dresden (TUD) wurde das bauphysikalische Konzept des Einhausungssystems optimiert. Die konstruktive Gestaltung eines Prototyps und des finalen Entwurfs erfolgte durch das Fachgebiet Konstruktives Entwerfen und Tragwerkslehre der Universität der Künste Berlin. Durch den Fachbereich Baustoffe der BAM erfolgten die Realisierung des Prototyps der Einhausung sowie ein umfangreiches Klimamonitoring an den Skulpturen. Anhand dieses interdisziplinären Projektes und ergänzt durch weitere Messungen wird gezeigt, mit welchen Methoden die für die Degradation von Marmor relevanten Mechanismen untersucht werden können. Die Erkenntnisse aus dem Projekt sind die Grundlage für die Entwicklung nachhaltiger Pflege- und Schutzkonzepte für die kulturhistorisch wertvollen Skulpturen. Nur mit solchen modernen konservatorischen Programmen können die Originalskulpturen im Berliner Stadtraum erlebbar bleiben.
T2 - Workshop Kulturerhaltung - Vom Dampfkessel zu Nanomaterialien
CY - Berlin, Germany
DA - 17.11.2021
KW - Baustoffe
KW - Marmor
KW - Verwitterung
KW - Kulturelles Erbe
KW - Wintereinhausungen
KW - Klima
KW - Zerstörungsfreie Prüfung
KW - Building materials
KW - Marble
KW - Degradation
KW - Cultural heritage
KW - Winter shelters
KW - Climate
KW - Nondestructive testing
PY - 2021
SN - 2567-1251
VL - 3
SP - 87
EP - 96
PB - Druckerei G. Bohm
CY - Berlin
AN - OPUS4-54637
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - Morell, Daniel
A1 - von der Au, Marcus
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
T1 - Transpassive Behavior of Equimolar CrMnFeCoNi and CrCoNi Multi‐Principal Element Alloys in an Alkaline NaCl Electrolyte
N2 - AbstractWe investigated the corrosion properties and transpassive behavior of CrMnFeCoNi and CrCoNi multi‐principal element alloys (MPEAs) in a 0.1 M NaCl electrolyte at pH 12. By using SECM‐based tip substrate voltammetry (TSV) in combination with the chemical analysis of the electrolyte, we were able to differentiate between anodic metal dissolution and oxygen evolution in the transpassive range. Our investigations have shown that CrCoNi has a significantly higher corrosion resistance compared to CrMnFeCoNi. In the studied alkaline environment, a transpassive oxide film is formed on the surface of CrCoNi during secondary passivation. This transpassive oxide film appears to play a significant role in oxygen evolution, as the increase in TSV currents at the microelectrode coincides with the corresponding current density plateau of the voltametric current trace. The formation of the transpassive oxide film was not observed in previous studies conducted in acidic environments. Moreover, the alkaline electrolyte induced a positive hysteresis and mild pitting corrosion, in addition to intergranular corrosion, which was the sole corrosion process observed at acidic pH levels. These findings enhance the understanding of the processes governing the transpassivity of CrMnFeCoNi and CrCoNi MPEAs in alkaline environments and have potential implications for the development of application‐tailored corrosion‐resistant MPEAs.
KW - Multi-principal element alloys
KW - MPEA
KW - Corrosion
KW - Oxygen evolution reaction
KW - Transpassive region
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611594
DO - https://doi.org/10.1002/celc.202400346
SN - 2196-0216
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-61159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, J.-C.
A1 - Fateri, M.
A1 - Schubert, T.
A1 - de Peindray d’Ambelle, L.
A1 - Simon, Sebastian
A1 - Gluth, Gregor
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Material aspects of sintering of EAC-1A lunar regolith simulant
N2 - Future lunar exploration will be based on in-situ resource utilization (ISRU) techniques. The most abundant raw material on the Moon is lunar regolith, which, however, is very scarce on Earth, making the study of simulants a necessity. The objective of this study is to characterize and investigate the sintering behavior of EAC-1A lunar regolith simulant. The characterization of the simulant included the determination of the phase assemblage, characteristic temperatures determination and water content analysis. The results are discussed in the context of sintering experiments of EAC-1A simulant, which showed that the material can be sintered to a relative density close to 90%, but only within a very narrow range of temperatures (20–30 °C). Sintering experiments were performed for sieved and unsieved, as well as for dried and non-dried specimens of EAC-1A. In addition, an analysis of the densification and mechanical properties of the sintered specimens was done. The sintering experiments at different temperatures showed that the finest fraction of sieved simulant can reach a higher maximum sintering temperature, and consequently a higher densification and biaxial strength. The non-dried powder exhibited higher densification and biaxial strength after sintering compared to the dried specimen. This difference was explained with a higher green density of the non-dried powder during pressing, rather than due to an actual influence on the sintering mechanism. Nevertheless, drying the powder prior to sintering is important to avoid the overestimation of the strength of specimens to be fabricated on the Moon.
KW - Lunar regolith
KW - Ceramics
KW - Microstructure
KW - Sintering
KW - Softening temperature
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592668
DO - https://doi.org/10.1038/s41598-023-50391-y
SN - 2045-2322
VL - 13
SP - 1
EP - 14
PB - Springer Nature
AN - OPUS4-59266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Biofuels: Alternative Feedstocks and Conversion Processes for the Production of Liquid and Gaseous Biofuels
N2 - his fully updated examination of sustainable processes for gaseous and liquid biofuels production, published for the second time within the series “Biomass, Biofuels, Biochemicals”, provides 33 contributions made by 120 authors. They present a holistic view of biofuels in research, operation, scale‐up and application. Comparing to the first edition, all chapters have been updated and new chapters covering topics of current interest, including sustainability and biohydrogen have been added.
By its wide overview on existing technologies, this book provides state‐of‐the‐art information and knowledge to the desired readership, like post‐graduates, researchers in the area of biofuels, wastewater treatment, alternate energy sources, renewable energy from biomass, chemical and biochemical engineers, microbiologists, biotechnologists working in academic and research institutes as well as in industry and governmental agencies.
KW - Biofuel
PY - 2020
DO - https://doi.org/10.1002/maco.202070074
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 7
SP - 1230
EP - 1231
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - A comparison of layerwise slurry deposition and (LSD-print) laser induced slip casting (LIS) for the additive manufacturing of advanced ceramics
N2 - The presentation gives an overview of two slurry-based additive manufacturing (AM) technologies specifically developed for advanced ceramic materials.
The “Layerwise Slurry Deposition” (LSD-print) is a modification of Binder Jetting making use of a ceramic slurry instead of a dry powder as a feedstock. In this process, a slurry is deposited layer-by-layer by means of a doctor blade and dried to achieve a highly packed powder layer, which is then printed by jetting a binder. The LSD-print technology combines the high-speed printing of binder jetting with the possibility of producing a variety of high-quality ceramics with properties comparable to those achieved by traditional processing.
The Laser Induced Slip casting (LIS) technology follows a novel working principle by locally drying and selectively consolidating layer-by-layer a ceramic green body in a vat of slurry, using a laser as energy source. LIS combines elements of Vat Photopolymerization with the use of water-based feedstocks containing a minimal amount of organic additives. The resulting technology can be directly integrated into a traditional ceramic process chain by manufacturing green bodies that are sintered without the need of a dedicated debinding.
Both technologies offer high flexibility in the ceramic feedstock used, especially concerning material and particle size. Advantages and disadvantages are briefly described to outline the specific features of LSD-print and LIS depending on the targeted application.
T2 - AM Ceramics
CY - Vienna, Austria
DA - 27.09.2023
KW - Additive Manufacturing
KW - Dental
KW - Ceramics
KW - Feldspar
PY - 2023
AN - OPUS4-58468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - LSD-print: a 10-years journey of an additive manufacturing technology from porcelain to technical ceramics
N2 - Motivated by the aim of developing an additive manufacturing (AM) technology easily integrated in the process chains of the ceramic industry, the LSD-print technology was conceived as a slurry-based variation of binder jetting (BJ).
BJ and other powder bed technologies (such as powder bed fusion) are amongst the most successful AM techniques, especially for metals and polymers, thanks to their high productivity and scalability. The possibility to use commercially available feedstocks (in the form of powders or granules) makes BJ also attractive for ceramic materials. The application of these techniques to most advanced ceramics has however been difficult so far, because of the limitations in depositing homogeneous layers with fine, typically poorly flowable powders.
In this context, the "layerwise slurry deposition" (LSD) was proposed at TU Clausthal (Germany) as a slurry-based deposition of ceramic layers by means of a doctor blade. Combined with layer-by-layer laser sintering of the material, the LSD process was originally demonstrated for the rapid prototyping of silicate ceramics. Due to the difficulties in controlling the microstructure and the defect formation in laser-sintered technical ceramics, the LSD process was later combined with inkjet printing in the LSD-print technology, which has been further developed at BAM (Germany) in the past decade.
The LSD-print technology combines the high speed of inkjet printing, typical of BJ, with the possibility of producing a variety of high-quality ceramics with properties comparable to those achieved by traditional processing. Due to the mechanical stability of the powder bed, the process can also be carried out with continuous layer deposition on a rotating platform, which further increases its productivity.
This presentation will delve into 10 years of research on the LSD-print of a wide variety of technical ceramics including alumina, silicon carbides and dental ceramics. The discussion highlights how a seemingly small process and feedstock modification (from powders to slurries) has great influence on the challenges and potential of this process, which are being addressed on its path to industrialization.
T2 - young Ceramists Additive Manufacturing Forum (yCAM) 2024
CY - Tampere, Finland
DA - 06.05.2024
KW - Additive Manufacturing
KW - Ceramic
KW - Layerwise slurry deposition
KW - Slurry
KW - LSD-print
PY - 2024
AN - OPUS4-60056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Günster, Jens
A1 - Wang, Gong
A1 - Tian, Xiaoyong
T1 - 3D Printing Technologies for Extreme Environment in Space
N2 - 3D printing technology can realize the rapid fabrication of complicated structures with short production chain, which just meet the requirements for space manufacturing in the future. However, 3D printing technologies in space are still challenging due to the harsh conditions, such as microgravity, high vacuum, and large temperature difference. Meanwhile, in-situ resource utilization and recycling must be considered as a cost effective and resilient resource for 3D printing in space. On the contrary, extreme environmental conditions such as high vacuum and microgravity can also offer significant advantages for advanced materials with high purity and performance. In-situ fabrication of ultra-large components would overcome the weight and structural limitations imposed by rocket launch and change the future strategy for space exploration. The aim of this specially issue is therefore to provide a platform for discussing the potential technologies for 3D printing in space.
KW - Additive Manufacturing
KW - space
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652654
DO - https://doi.org/10.1016/j.amf.2025.200248
SN - 2950-4317
VL - 4
IS - 3
SP - 1
EP - 2
PB - Elsevier
AN - OPUS4-65265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Metallic Materials for Geothermal Applications
N2 - The aim of the work presented was the evaluation of corrosion resistance
of various materials in geothermal Waters as a base to create a catalogue of suitable materials for applications in (not only) German geothermal power plants.
Users shall be enabled to have a basis for designing such facilities. High alloyed corrosion resistant alloys are suitable and do not cause copper or lead deposition. They shall be chosen for future design of the piping system, either in massive or in cladded form, if crevices formation with non-metallic materials can be prevented!
T2 - IFPEN-Workshop: Corrosion in Low-Carbon Energies
CY - Online meeting
DA - 03.11.2020
KW - Geothermal
KW - Corrosion
KW - Saline brine
PY - 2020
AN - OPUS4-51511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
A1 - Sänger, Johanna
A1 - Pauw, Brian Richard
T1 - Two-Photon-Polymerization for Ceramics Powder Processing
N2 - Manipulating ceramic powder compacts and ceramic suspensions (slurries) within their volume with light requires a minimum transparency of the materials. Compared to polymers and metals, ceramic materials are unique as they offer a wide electronic band gap and thus a wide optical window of transparency. The optical window typically ranges from below 0.3 µm up to 5µm wavelength. Hence, to penetrate with laser light into the volume of a ceramic powder compound its light scattering properties need to be investigated and tailored. In the present study we introduce the physical background and material development strategies to apply two-photon-polymerization (2PP) for the additive manufacture of filigree structures within the volume of ceramic slurries.
T2 - ECerSXVIII Conference Exhebition of the European Ceramic Society
CY - Lyon, France
DA - 02.07.2023
KW - Additive Manufacturing
KW - Transparent ceramics
PY - 2023
AN - OPUS4-59883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Nanopatterned and Nanoparticle‐Modified Electrodes
N2 - Since nanoscience has a tremendous impact on the development of electrochemistry, Wiley‐VCH paid attention to that by publishing thisbook as volume 17 within the series “Advances in Electrochemical Science and Engineering”.
This collection of “nanoaspects”on electrodes provides a helpful overview on principles and current findings to readers interested in such applications. It fulfills its intention of being “a valuable resource for researchers working in such fields as electrochemistry, materials science, spectroscopy, analytical and medicinal chemistry”.
KW - Electrochemistry
KW - Nanoparticle
PY - 2020
DO - https://doi.org/10.1002/maco.202070014
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 1
SP - 179
EP - 180
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50205
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - Corrosive CO2-stream components, challenging for materials to be used in CC(U)S applications
N2 - This contribution provides current findings regarding materials susceptibility for CCUS applications. Basing on results gathered in 2 German long-term projects (COORAL and CLUSTER) suitable materials are introduced as well as dominating impurities of the CO2 stream and corrosion mechanisms. Investigations cover the whole CCUS process chain and provide the following recommendations for certain parts. Commercially available carbon steels are suitable for compression and pipelines as long as moisture content and impurities are limited (water 50 to 100 ppmv, SO2 and NO2 ca. 100 ppmv).
Corrosion rates increase with increasing water content (0.2 – 20 mm/a).
Condensation of acids and therefore droplet formation is always possible, even at low water contents.
A low SO2 content within the CO2-stream might be more important than a low water content.
Cr13-steels showed a general susceptibility to shallow pitting and pitting. So, they seem to be not suitable for CCUS applications.
Low alloyed steels showed better corrosion behavior (predictable uniform corrosion).
For direct contact with saline aquifer fluids only high alloyed steels shall be used.
T2 - WCO Webinar on the occasion of Corrosion Awareness Day - Corrosion and Low-Carbon Energies
CY - Frankfurt, Germany
DA - 24.04.2020
KW - CO2-corrosion
KW - CCUS
KW - Pipeline
KW - Carbon Capture
PY - 2020
AN - OPUS4-50699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Rezension: Halliday Physik für natur‐ und ingenieurwissenschaftliche Studiengänge – Lehr‐ und Übungsbuch
N2 - Die von Stephan W. Koch herausgegebene Übersetzung der erweiterten zehnten Auflage von ,,Fundamentals of Physics“ liefert ein Schwergewicht geballten Physikwissens und Übungsmaterial. Die Bücher bieten nicht nur Studierenden hilfreiches Lernmaterial, sondern sind auch für allgemein Physik‐Interessierte ein wertvolles Nachschlagewerk. Wer sich bereits mit dem umfassenderen „großen Bruder“ vertraut gemacht hat und diesen nutzt, findet im Lehrbuch nichts Neues. Jedoch liefert das Übungsbuch im Vergleich zum Arbeitsbuch von 2018 neue und übersichtlichere Übungsbeispiele.
Die neue Auflage wurde didaktisch komplett neu strukturiert und einige Kapitel vollständig überarbeitet. Ein Novum stellt dabei die modulare Organisation dar, bei der jeder Abschnitt mit Lernzielen und Schlüsselideen beginnt. Kontrollfragen im Text tragen entscheidend zum Rekapitulieren des Gelesenen bei. Jedes Kapitel endet mit einer Zusammenfassung und Fragen zum vermittelten Stoff. Als Ergänzung dient das ausführliche Übungsbuch mit Aufgaben und Lösungen zu den jeweiligen Kapiteln des Lehrbuches.
Die 37 Kapitel machen verständlich mit den einzelnen Gebieten der Physik vertraut.
KW - Physik
KW - Thermodynamik
PY - 2020
DO - https://doi.org/10.1002/maco.202070066
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 6
SP - 3
EP - 4
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50839
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Rezension: Kurzlehrbuch Physikalische Chemie: für natur‐ und ingenieurwissenschaftliche Studiengänge
N2 - Wem das Standardwerk der Physikalischen Chemie „Der Atkins“ zunächst zu überwältigend erscheint, dem gelingt mit diesem, nunmehr in der fünften Auflage erschienenen, Kurzlehrbuch sicherlich der Einstig in die Thematik. Studierenden im Bachelor‐ und Mastergang bietet es ein sehr hilfreiches Nachschlagewerk während des Studiums und zur Prüfungsvorbereitung. Die vielfältigen Übungen und Anwendungen am Ende jedes Kapitels, besser gesagt von jedem Fokus, tragen entscheidend zum Verständnis und Überprüfen des Gelernten bei. Sogenannte „Toolkits“ wiederholen an den entsprechenden Stellen inprägnanter Form mathematische Herangehensweisen und Techniken, die das Textverständnis unterstützen. Bei der Überarbeitung der vorherigen Ausgabe flossen nicht nur Anmerkungen von Lehrenden, sondern auch wertvolle Einblicke aus der Sicht der Lernenden, ein, was sich im Aufbau des Buches widerspiegelt.
Dieses didaktisch und inhaltlich sehr gut aufgebaute Lehrbuch erfüllt auf jeden Fall seine Intension und weckt die Neugierde auf das im Frühjahr 2020 erscheinende dazugehörige Arbeitsbuch.
KW - Elektrochemie
KW - Korrosion
PY - 2020
DO - https://doi.org/10.1002/maco.202070036
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 3
SP - 3
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50490
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Materials Handbook–A Concise Desktop Reference
N2 - This concise reference book,consisting of 2 volumes, provides “key scientific and technical properties and data” for “materials scientists, metallurgists, engineers,chemists, and physicists as well as academic staff, technicians, and students” dealing with such kind of materials.
Within its 3rd edition the previous work was extended by a chapter on occupational health and safety issues of materials, beside of the update of whole content. Within 22 chapters materials properties and data are summarized in many tables. Some facts are illustrated by drawings and diagrams for better understandability. Each chapter ends with a part on further reading arranged accordingly.
KW - Corrosion
KW - Materials
KW - Corrosivity
KW - Resistance
PY - 2020
DO - https://doi.org/10.1002/maco.202070034
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 3
SP - 509
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Rezension: Zerstörungsfreie Werkstück- und Werkstoffprüfung
N2 - Das 1988 erstmalig erschienene und bewährte Fachbuch wurde auf den neuesten Stand gebracht und im Rahmen der „Kontakt & Studium“‐Serie der Technischen Akademie Esslingen als Band 243 neu aufgelegt.
In 12 Kapiteln bieten die 12 erfahrenen Autoren einen Überblick über die gebräuchlichsten Formen zerstörungsfreier Prüfverfahren als Grundlage für die Dokumentation der Produktqualität während des gesamten Herstellungsprozesses und deren elementare Bedeutung für die Produkthaftung.
Dieses Lehrbuch dient nicht nur Universitäts‐Studierenden, sondern bietet auch jedem interessierten Leser einen Überblick der gebräuchlichen Verfahren.
KW - Werkstoffprüfung
KW - ZFP
PY - 2020
DO - https://doi.org/10.1002/maco.202070076
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 7
SP - 3
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50959
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Seifert, Lando
T1 - Review: Concrete Repair to EN 1504: Diagnosis, Design, Principles and Practice
N2 - In 2019 CRC Press published the “Concrete Repair to EN 1504” as paperback. This issue does not differ in terms of content from the hardback publication of 2014. Like the previous version, the book covers both detailed background information on repair procedures of reinforced concrete structures and provides a reference work for technicians and people who are involved with the maintenance of these structures, according to EN 1504.
The book presents a high number of figures and tables, i.e., approximately one illustration per page.
For readers who prefer a more comfortable to handle paperback, the book is recommended; however, the hardback from 2014 is still up‐to‐date.
KW - Corrosion
KW - Concrete
KW - Bridge
PY - 2020
DO - https://doi.org/10.1002/maco.202070064
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 6
SP - 1036
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Ackermann, H.
A1 - Pötzsch, Sina
A1 - Weltschev, Margit
A1 - Bäßler, Ralph
A1 - Plum, W.
T1 - Entwicklung einer Prüfmethode zur Bewertung der Materialbeständigkeit von Bauteilen in Mitteldestillatanwendungen
N2 - Im Vorhaben wurde eine forcierte Prüfmethode zur Bestimmung der Beständigkeit von metallenen Werkstoffen gegenüber Brennstoffen aus Mitteldestillaten und Gemischen aus Mitteldestillat und paraffinischen Kohlenwasserstoffen, die jeweils Fettsäuremethylester (FAME) als biogene Komponente enthalten, entwickelt. Bei der Prüfmethode werden Prüfkörper des jeweiligen Werkstoffes in speziellen Prüfmedien ausgelagert. Die Zusammensetzung von zwei Prüfmedien wurde im Vorhaben erarbeitet. Diese Prüfmedien erfassen die Effekte der Alterung des FAME, die zu erwarten sind, wenn der Brennstoff länger als 2 Jahre im Feld lagert. Sie decken den Bereich bis 20 % (V/V) FAME-Anteil ab. Die Auslagerung kann bei geringem Aufwand unter Atmosphärendruck durchgeführt werden.
Die Eignung einer Auswahl von metallenen Werkstoffen und Polymerwerkstoffen, die für Versorgungsanlagen für Mitteldestillat relevant sind, wurde durch Auslagerung in folgenden nicht gealterten Brennstoffen bestimmt: Heizöl EL schwefelarm (B0), Heizöl EL schwefelarm mit 20 % (V/V) FAME (B20), FAME (B100) und hydriertes Pflanzenöl (HVO). Die Werkstoffe wurden auch in einem 1 Jahr gealterten B20 und einem 8 Jahre gealtertem B10 ausgelagert. Die Temperatur bei der Auslagerung betrug 50 °C für die metallenen Werkstoffe und 40 °C und 70 °C für die Polymerwerkstoffe. Die Ergebnisse der Beständigkeitsbewertung wurden in Beständigkeitslisten zusammengefasst. Die mit B20 erhaltenen Bewertungen gelten generell für Gemische aus Heizöl EL schwefelarm und FAME mit einem FAME-Gehalt bis 20 % (V/V). Sie sind auch auf Gemische aus Dieselkraftstoff und FAME mit einem FAME-Gehalt bis 20 %(V/V) übertragbar.
Die forcierte Prüfmethode kann insbesondere KMUs bei der Weiterentwicklung von bestehenden Produkten und der Entwicklung von neuen Produkten als ein kostengünstiger Schnelltest zur Überprüfung der Werkstoff- und Bauteilbeständigkeit gegenüber Mitteldestillaten mit hohem FAME-Anteil dienen. Sie kann für die Hersteller die Sicherheit erhöhen, dass Bauteile die Freigabeprüfungen der Bauaufsicht bestehen, wobei die Freigabe jedoch nur für Deutschland gültig ist.
Die Erkenntnisse des Forschungsvorhabens können in eine harmonisierte Europäische Norm für alternative Brenn- und Kraftstoffe einfließen. Diese ist für die Bauteilhersteller die Voraussetzung für die Erschließung des europäischen Marktes.
N2 - Within this project, a forced test method was developed to determine the resistance of metallic materials to middle distillate fuels and mixtures of middle distillate and paraffinic hydrocarbons both with fatty acid methyl ester (FAME) as a biogenic component. In the method, specimens of the material are immersed in special test media. The compositions of two test media were developed within the project. These test media include the influence of aging of the FAME which is to be expected after a storage of the fuel exceeding 2 years in the field. They cover a range of up to 20 % (v/v) FAME content. The exposure test can be carried out at ambient pressure with little effort.
Suitability of selected metallic and polymer materials relevant for middle distillate supply systems was determined by exposure to the following non-aged fuels: low-sulfur light fuel oil (B0), low-sulfur light fuel oil with 20 % (v/v) FAME (B20), FAME (B100) and hydrogenated vegetable oil (HVO). The materials were also exposed in the 1-year-aged B20 and 8-year-aged B10. Test temperature was 50 °C for metallic materials and 40 °C and 70 °C for polymers. Resulting materials resistances were summarized in resistance tables. Resistances obtained in B20 are valid for any mixture of low-sulfur light fuel oil and FAME containing up to 20 % (v/v) FAME. They are also transferable to mixtures of diesel and FAME having a FAME content of up to 20 % (v/v).
This method with special test media is a cost-effective rapid test for checking resistance of materials to middle distillates having a high FAME content. It can support SMEs manufacturing components for supply systems in further development of existing and new products. It increases the manufacturers' certainty that components will pass approval tests of authorities.
Results of this research project can be incorporated into a harmonized European standard for alternative fuels. This is the prerequisite for component manufacturers to access the European market.
KW - Heizöl
KW - FAME
KW - Biobrennstoff
PY - 2020
UR - https://dgmk.de/publikationen/entwicklung-einer-pruefmethode-zur-bewertung-der-materialbestaendigkeit-von-bauteilen-in-mitteldestillatanwendungen/
SN - 978-3-947716-14-2
SN - 0937-9762
SP - 1
EP - 153
PB - DGMK
CY - Hamburg
AN - OPUS4-51110
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Le, Quynh Hoa
T1 - CO2-stream impurities and their effects on corrosion susceptibility of materials to be used in CCUS systems
N2 - Carbon Capture Utilization and Storage (CCUS) is a promising technology to reach the target for reduction of CO2 emissions. Crucial points for a sustainable and future-proof CCUS system are reliability and cost efficiency of the whole process chain, including separation of CO2 from the source, compression of CO2, its subsequent transportation to the injection site and injection into geological formations, e.g. aquifers. Recent studies have shown that even at a very low concentration of impurities, condensation of sulfuric and nitric acids in dense phase CO2 are possible and observable. Thus, impact of impure CO2 stream toward corrosion susceptibility of materials to be used in CCUS system need to be considered. In this talk, basing on results achieved from two German long-term projects (COORAL and CLUSTER), the dominating impurities of the CO2 stream and corrosion mechanisms are addressed. Investigations cover the whole CCUS process chain and provide a material recommendation for certain parts.
T2 - Corrosion in Low-Carbon Energies - IFPEN-Lyon
CY - Online meeting
DA - 03.11.2020
KW - Corrosion
KW - CCUS
KW - Carbon dioxide
PY - 2020
AN - OPUS4-51509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Rezension: Polymere ‐ Chemie und Strukturen; Herstellung, Charakterisierung und Werkstoffe
N2 - Polymere sind aus unserem Alltag nicht mehr wegzudenken. Häufig haben wir mit Plexiglas, Dichtmassen, Klebestreifen und vielen Verpackungsmaterialien zu tun. Aber auch Spezialanwendungen (z.B. in der Pharmazie) bilden Einsatzbereiche dieser Werkstoffe.
Der Vermittlung der Grundlagen polymerer Werkstoffe in den Studienfächern Chemie, Materialwissenschaften und der Ingenieur‐ und Lebenswissenschaften haben sich die Autoren verschrieben, wobei sie zur verständlichen Anschauung bewusst auf das Beispiel Styrol als „Versuchskaninchen“ zurückgreifen.
Dieses Lehrbuch wird seinem Anspruch gerecht, einen leichten Einstieg in die Polymerwissenschaften zu ermöglichen. Es liefert eine Übersicht über die Polymerklassen Thermoplaste, Duroplaste und Elastomere mit ihren Eigenschaften und zeigt, welche Synthesestrategie zu dem Produkt mit den gewünschten Eigenschaften führt. Anhand von Beispielen aus dem Alltag werden gängige Vertreter verständlich vorgestellt.
KW - Polymerwerkstoff
PY - 2020
DO - https://doi.org/10.1002/maco.202070126
SN - 1521-4176
VL - 71
IS - 12
SP - 2
EP - 3
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51777
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Rezension: Schweißen im Stahlbau, Normen für die Herstellerqualifikation nach DIN EN 1090‐1
N2 - Schlosserei‐, Metall‐ und Stahlbaubetriebe müssen seit Juli 2012 für tragende Bauteile aus Stahl und Aluminium, die als Bauprodukte in Verkehr gebracht werden sollen, einen Konformitätsnachweis nach DIN EN 1090‐1 erbringen.
Mit der sechsten Auflage des Normen‐Handbuches „Schweißen im Stahlbau“ setzen das Deutsche Institut für Normung e.V. (DIN) und der Deutsche Verband für Schweißen und verwandte Verfahren e.V. (DVS) ihre bewährte Strategie fort, die dieses Thema betreffenden aktuellen Normen und Regelwerke durch J. W. Mußmann in gut aufbereiteter Form kompakt zusammenzustellen.
KW - Korrosion
KW - Schweißen
KW - Schweißnaht
PY - 2020
DO - https://doi.org/10.1002/maco.202070116
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 11
SP - 3
EP - 4
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51512
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Corrosion of Linings and Coatings: Cathodic and Inhibitor Protection and Corrosion Monitoring
N2 - This paperback issue of the 2007 hardcover version within the “Corrosion Engineering Handbook” series presents various materials and methods for controlling and protecting against corrosion instead of using expensive alloys to construct a tank or processing vessel.
This book is a very comprehensive collection of the current knowledge about applied linings and coatings. So, it fulfills its intension, “that regardless of what is being built, … information for … whoever is responsible for the selection of material of construction will be found in this book to enable them to avoid unnecessary loss of material through corrosion”, to a very large extent.
KW - Corrosion
KW - Coating
KW - Lining
KW - Cathodic protection
PY - 2020
DO - https://doi.org/10.1002/maco.202070104
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 10
SP - 1756
EP - 1757
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bäßler, Ralph
T1 - Review: Materials Informatics -Metals, Tools and Applications
N2 - Since data processing has now also found its way into materials science, there has been a great demand from users for a corresponding textbook. This book provides a guide to the latest advances of materials informatics and data mining for materials science. 46 authors introduce readers to methods, present tools and case studies to illustrate the power of materials informatics within this new field of application.
KW - Corrosion
KW - Materials behavior
PY - 2020
DO - https://doi.org/10.1002/maco.202070114
SN - 1521-4176
SN - 0947-5117
VL - 71
IS - 11
SP - 1928
EP - 1929
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Aristia, Gabriela
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
T1 - Study of Polyaniline/Silicon Dioxide based Coating on Carbon Steel in Artificial Geothermal Brine
N2 - Geothermal brines are corrosive in nature because of their salt contents and high temperatures. Therefore, they pose a major challenge to geothermal power-plants, which are mostly built of low alloyed steels, e.g., carbon steel. Carbon steel is susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic-saline properties. To overcome this limitation, geothermal power plants should be built by either high alloyed materials or by integrating protection systems on carbon steel, such as coatings and inhibitors. We studied a coating system containing polyaniline/silicon dioxide basing on locally available resources that provides protection against corrosion of carbon steel and enhance the thermal resistance in geothermal environments. Here, exposure and electrochemical tests of coated carbon steels were performed in an artificial geothermal brine. The solution had a pH of 4, with the composition of 1,500 mg/L of chlorides, which is based on the chemical analysis of geothermal brine found in Sibayak, Indonesia. All exposure tests were conducted using autoclaves at 150 °C with a total pressure of 1 MPa, which was performed for up to six months to evaluate the durability of the coating system. Post-experimental analyses were performed by assessing the surface of specimens using optical and electron microscopes. On the other hand, electrochemical tests were performed for seven days at 25 °C and 150 °C to investigate the kinetics of electrochemical reactions by measuring open circuit potential and electrochemical impedance spectra. Experimental results showed the corrosion resistance of PANI/SiO2 composite coatings, where polyaniline and SiO2 play their roles as stabilizers.
T2 - World Geothermal Congress
CY - Online meeting
DA - 30.03.2021
KW - Coatings
KW - Corrosion
KW - Polyaniline
KW - Sibayak
KW - SiO2
PY - 2021
SP - 1
EP - 7
AN - OPUS4-52830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bäßler, Ralph
T1 - ISO 27913 - Example For Successful Standardization Activities In The Field Of CCUS
N2 - Since 2016 ISO Technical Committee (TC) 265 is working on standardization the whole CCS-process chain. Around 30 countries are working together to provide international guidelines. As ISO 27913 was the first standard finished within these activities it is already in the stage of first revision.
The objective of ISO 27913 is “to provide specific requirements and recommendations on certain aspects of safe and reliable design, construction and operation of pipelines intended for the large-scale transportation of CO2 that are not already covered in existing pipeline standards such as ISO 13623, ASME B31.8, EN 1594, AS 2885 or other standards. Existing pipeline standards cover many of the issues related to the design and construction of CO2 pipelines; however, there are some CO2 specific issues that are not adequately covered in these standards. The purpose of this document is to cover these issues consistently. Hence, this document is not a standalone standard, but is written to be a supplement to other existing pipeline standards for natural gas or liquids for both onshore and offshore pipelines.”
This contribution shall provide information on the content, the current stage of the revision process, encourage to contribute to this standard and make listeners aware to consider the influence of ISO standard on documents currently in draft.
T2 - AMPP's Annual Conference + Expo 2024
CY - New Orleans, LA, USA
DA - 02.03.2024
KW - Corrosion resistant materials
KW - Carbon dioxide
KW - Corrosion prevention
KW - Standardization
KW - CCUS
KW - CCS
KW - CCU
PY - 2024
SP - 1
EP - 6
PB - AMPP
CY - Houston
AN - OPUS4-59735
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - Water-based additive manufacturing of ceramics by Laser-Induced Slip Casting (LIS)
N2 - The Laser-Induced Slip Casting is an additive manufacturing technology specifically developed for ceramic materials using water-based ceramic slurries. The process takes place layer-by-layer in a similar fashion as top-down vat photopolymerization, selectively consolidating each layer by means of a laser energy source positioned on the top. Contrary to vat photopolymerization, in which the consolidation is achieved by selectively cross-linking a ceramic-filled resin, LIS uses water-based slurries with a low amount of organic additives (typically < 5 wt%) as feedstocks.
In LIS, a green body is formed by local evaporation of water which causes the suspension to collapse forming a cast, following a mechanism similar to slip casting. Only a small content of organic additives is needed to effectively disperse the ceramic particles and to increase the green strength.
The technology is very versatile and can be applied to all ceramic systems that can be dispersed in water. One of the main advantages is that even dark materials such as silicon carbide can be processed without issues related to light scattering and absorption.
The presentation will discuss strengths and limitations of LIS compared to other AM technologies and will highlight the latest results for alumina and for silicon carbide ceramics.
T2 - 48th International Conference and Expo on Advanced Ceramics and Composites (ICACC2024)
CY - Daytona, FL, USA
DA - 28.01.2024
KW - Additive Manufacturing
KW - Ceramic
KW - Water-based
KW - Slurry
KW - Laser
PY - 2024
AN - OPUS4-60054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zocca, Andrea
T1 - An overview of ceramic AM with focus on bioceramics and powder bed technologies
N2 - The presentation will start with an overview of ceramic additive manufacturing (AM) technologies and will discuss the potential of AM in the field of bioceramics.
The presentation will then focus on two possible use cases of binder jetting technologies.
In the first example, standard powder-based binder jetting is used to manufacture a porous implant design for large scale bone defects. The related challenges in the process chain will be discussed, from powder synthesis to sintering and characterization of the printed part.
In the second example, the LSD-print slurry-based binder jetting technology is presented as a possibility to adapt powder-bed AM to produce dense ceramic parts. The use case will focus on an application in the field of dental ceramics, specifically for the manufacturing of patient individualized single tooth restorations (veneers, crowns) with a high throughput process chain.
T2 - BioCAM - Additive Manufacturing Applied to Bioceramics
CY - Mons, Belgium
DA - 06.12.2023
KW - Additive Manufacturing
KW - Bioceramic
KW - Binder Jetting
PY - 2023
AN - OPUS4-60053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Günster, Jens
T1 - Tailoring powder properties for the light based volumetric additive manufacture of Ceramics
N2 - In order to be able to manipulate ceramic powder compacts and ceramic suspensions (slurries) within their volume with light, a minimum transparency of the materials is required. Compared to polymers and metals, ceramic materials are characterized by the fact that they have a wide electronic band gap and therefore a wide optical window of transparency. The optical window generally ranges from less than 0.3 µm to 5 µm wavelength. In order to focus light into the volume of a ceramic powder compact, its light scattering properties must therefore be tailored. In this study, we present the physical background and material development strategies for the application of two-photon polymerization (2PP) and selective volumetric sintering for the additive manufacturing of structures in the volume of ceramic slips and green compacts.
T2 - SmartMade 2024
CY - Osaka, Japan
DA - 10.04.2024
KW - Additive Manufacturing
KW - Two Photon Polymerization
KW - Advanced ceramics
PY - 2024
AN - OPUS4-59888
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohabbat, Abdulrahman
A1 - Boldog, István
A1 - Reistel, Nils
A1 - de Sousa Amadeu, Nader
A1 - Möllmer, Jens
A1 - Lange, Marcus
A1 - Limon, Aysenur
A1 - Seiffert, Philipp
A1 - Michalski, Julia
A1 - Janiak, Christoph
T1 - P4O10-mediated synthesis of polar polyphosphoric acid-covalent triazine framework composites from aromatic amides for improved water and SO2 sorption
N2 - Polycondensation of various aromatic amides in P4O10 at 400 8C yields covalent triazine frameworks intergrown with a polyphosphoric acid framework (POF-CTFs). Compared to ionothermal analogs, they feature a shorter reaction time and strongly increased framework polarity for water and SO2 uptake, and SO2/CO2
selectivity
KW - COF
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644208
DO - https://doi.org/10.1039/d5cc03419a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Comparative chemical analysis of Ni-Fe oxide nanoparticles
N2 - Ni-Fe oxide nanoparticles have gained a lot of interest because of their high activity in the oxygen evolution reaction (OER) which is crucial for water splitting. [1] Although there have been great efforts in the last years, the understanding of the synergistic effect between Fe and Ni is still under discussion.
Therefore, we prepared different Ni-Fe oxide nanoparticles with different compositions from pure iron oxide to pure nickel oxide adapting a known procedure. [2,3] Size and morphology of the nanoparticles depend on the composition which was shown with Transmission Electron Microscopy (TEM). The compositions of the nanoparticles were measured with a comparative approach using X-ray Photoelectron Spectroscopy (XPS), Hard X-ray Photoelectron Spectroscopy (HAXPES), and Energy Dispersive X-Ray Spectroscopy (EDS) coupled with the TEM providing detailed chemical information of the nanoparticles in different sample regions. EDS reveals that the different sample regions are dominated by one of the components, Fe or Ni, but a slight mixing between the components can be found (see Figure 1), which was confirmed with X-ray Diffraction (XRD). XPS indicates the enrichment of Fe at the sample surface, while HAXPES and EDS data agree on the stoichiometry of the bulk. High-resolution XPS and HAXPES exhibit some differences in the valence states of Fe and Ni, whereas Ni seems to be easier to reduce than Fe. Further investigations combining these different techniques and additionally Secondary Ion Mass Spectrometry (ToF-SIMS) are ongoing by using in situ approaches and coupling cyclic voltammetry to the analytical techniques.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Oxygen evolution reaction
KW - Transmission Electron Microscopy
KW - (Hard) X-ray Photoelectron Spectroscopy
KW - Synergistic effects
PY - 2024
AN - OPUS4-60534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wachsmann, Sebastian B.
A1 - Ruf, Matthias
A1 - Prinz, Carsten
A1 - Oehlsen, Nina
A1 - Zhou, Xiaoru
A1 - Dyballa, Michael
A1 - Arweiler, Christine
A1 - Leistner, Philip
A1 - Steeb, Holger
A1 - Garrecht, Harald
A1 - Laschat, Sabine
A1 - Stegbauer, Linus
T1 - Chitin/Chitosan Biocomposite Foams with Chitins from Different Organisms for Sound Absorption
N2 - Foams are widely used for applications in construction, energy absorption, and building insulation. We developed sustainable chitin/chitosan-based foams derived from snow crab and Aspergillus niger (α-chitin) and from squid (β-chitin), which were obtained via a “shake and bake” process. The foam structure, mechanical, thermophysical, sound absorption, and flammability properties were studied. Stable foams were obtained from snow crab and squid chitin, whereas A.niger-based foams were inhomogeneous. Foams derived from the former biomass sources displayed densities of 0.07−0.30 g/cm3 and bulk porosities of 78−94% with only a minimal number of closed pores. According to mercury porosimetry (MP) and X-ray computed microtomography (μXRCT), pore sizes ranged from 3 μm to 1.5 mm, with the majority of pores being larger than 400 μm. In mechanical compression tests, β-chitin-based foams showed higher specific compressive strength and modulus (up to 0.1 * = 9.00 MPa/E* = 107.37 MPa) compared to the α-chitin-based series. Dynamic vapor sorption (DVS) measurements revealed that the β-chitin (from squid) series overall took up more water vapor (≤40 wt %) than the α-chitin (from snow crab) series (≤33 wt %). Flammability tests showed that the developed foams were suitable for fire protection class E, superior to common polyurethane (PU) foams, and sound absorption tests showed promising results for applications only little influenced by humidity.
KW - Chitin
KW - Foam
KW - Biocomposite
KW - Sound absorption
KW - Flammability
KW - Mercury porosimetry
KW - Dynamic vapor sorption
PY - 2024
DO - https://doi.org/10.1021/acssuschemeng.4c00044
VL - 12
IS - 32
SP - 11879
EP - 11890
PB - American Chemical Society (ACS)
AN - OPUS4-60819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Influence of Surface Chemistry and Size on the Stability of β-NaYF4:Yb,Er Nanocrystals in Various Environments
N2 - The use of inorganic lanthanide-doped upconversion nanoparticles (UCNP) in bioimaging and cellular studies requires biocompatible particles. One possible cause of UCNP toxicity is the release of potentially harmful fluoride and lanthanide ions as revealed by dilution studies in aqueous environments, particularly under high dilution conditions. To address this issue, suitable surface coatings preventing such effects in combination with fast screening methods suited for online monitoring and in situ analyses are desired.
Here we present systematic studies of differently sized β-NaYF4:Yb,Er UCNP stabilized with different surface coatings and hydrophilic ligands varying in binding strength to the particle surface in various aqueous environments at different temperatures and UCNP concentrations. The concentration of the fluoride and lanthanide ions released upon particle dissolution was quantified electrochemically with a fluoride ion-sensitive electrode and inductively coupled plasma optical emission spectrometry (ICP-OES) and monitored fluorometrically, thereby exploiting the sensitivity of the upconversion luminescence to changes in size and surface chemistry. Moreover, changes in surface chemistry were determined with X-Ray photoelectron spectroscopy (XPS). Based upon our results, we could derive optimum screening parameters for UCNP stability studies and determine conditions and coating procedures and ligands for enhancing UCNP stability in aqueous environments.
T2 - UPCON2021
CY - Online meeting
DA - 06.04.2021
KW - Fluorescence
KW - Lifetime
KW - Method
KW - Quantification
KW - Stability
KW - Coating
KW - Surface chemistry
KW - Lanthanide
KW - Fluoride
KW - Electrochemistry
KW - ICP-OES
KW - Upconversion
KW - Nano
KW - Particle
KW - Aging
KW - Quality assurance
KW - Mass spectrometry
KW - XPS
PY - 2021
AN - OPUS4-52411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abram, Sarah-Luise
T1 - Monodisperse iron oxide nanoparticles as reference material candidate for particle size measurements
N2 - In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important, especially with respect to the assessment of their environmental or biological impact. Furthermore, the European Commission’s REACH Regulations require the registration of nanomaterials traded in quantities of at least 1 ton. Powders or dispersions where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as nanomaterials. This creates a need for industrial manufacturers and research or analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution and will also target other key parameters like shape, structure, porosity or functional properties. In this respect, materials like iron oxide or titanium dioxide are considered as candidates to complement the already available silica, Au, Ag, and polystyrene reference nanoparticles.
The thermal decomposition of iron oleate precursors in high boiling organic solvents can provide large quantities of iron oxide nanoparticles that can be varied in size and shape.[1, 2] The presence of oleic acid or other hydrophobic ligands as capping agents ensures stable dispersion in nonpolar solvents. Such monodisperse, spherical particles were synthesized at BAM and pre-characterized by electron microscopy (TEM, SEM including the transmission mode STEM-in-SEM) and dynamic light scattering comparing cumulants analysis and frequency power spectrum.
1. REACH regulations and nanosafety concerns create a strong need for nano reference materials with diverse properties.
2. Iron oxide nanoparticles are under development as new candidate reference material at BAM.
3. Narrow particle size distribution confirmed by light scattering and electron microscopy.
T2 - Nanosafety 2020
CY - Online meeting
DA - 05.10.2020
KW - Iron oxide nanoparticles
KW - Reference material
KW - Particle size
KW - Electron microscopy
KW - Nanoplattform
PY - 2020
AN - OPUS4-52774
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abram, Sarah-Luise
T1 - Iron oxide nanoparticles as a reference material candidate for particle size measurements
N2 - This poster presentation covers the development of iron oxide nanoparticles as reference material candidate in the context of the project "Nanoplattform".
T2 - EMRS Spring Meeting
CY - Online meeting
DA - 31.05.2021
KW - Iron oxide nanoparticles
KW - Reference material
KW - Particle size
KW - Transmission electron microscopy
KW - Small angle x-ray scattering
PY - 2021
AN - OPUS4-52773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cancella, Erick Paiva
A1 - de Paula Guarnieri, Guilherme
A1 - de Sousa Amadeu, Nader
A1 - Radtke, Martin
A1 - Garcia, Rodrigo Henrique
A1 - de Azevedo, Eduardo Ribeiro
A1 - Cosentino, Ivana Conte
A1 - Mascarenhas, Yvonne Primerano
A1 - Nery, José Geraldo
T1 - Synthesis and physicochemical characterization of a novel bismuth silicate templated by tetrapropylammonium bromide and polydiallyldimethylammonium chloride
N2 - A bismuth silicate (BiSi-1) was hydrothermally synthesized using tetrapropylammonium bromide (TPA·Br) as the organic structure-directing agent and shown by multi-scale characterization to be distinct from known Bi–silicates. Powder X-ray diffraction is indexable with an orthorhombic metric (a = 23.234 Å, b = 17.109 Å, c = 3.897 Å), consistent with a highly anisotropic, possibly layered framework. High-resolution TEM/SAED reveals nanocrystalline, plate-like domains assembled into sub-micrometric aggregates with locally oriented lamellae; lattice fringes (0.27–0.32 nm) match the strongest XRD spacings. Solid-state NMR establishes a silica-rich network with a dominant Q4 population (77%) and minor Q3 (11%) and Q2 (12%) sites; the contact-time dependence of 1H to 29Si cross-polarization is consistent with increasing proximal-proton density from Q4 to Q2. Aging to 24 h sharpens the 29Si lineshape, while calcination progressively removes the OSDA and vicinal hydroxyls; at 750 °C, 29Si spectra indicate framework densification/rearrangement. XANES/EXAFS places bismuth predominantly as Bi3+ in an oxide-like environment with a pronounced Bi–O first shell and no detectable Bi⁰ or Bi–Br contributions. ICP–OES yields a reproducible Bi/Si atomic ratio of 1:3. Thermogravimetry shows stepwise desorption, dehydroxylation, and template removal, with thermal stability maintained to 750 °C. Nitrogen sorption confirms mesoporosity in the as-made and Soxhlet-extracted solids (the latter exhibiting the highest surface area), whereas high-temperature calcination reduces porosity. Collectively, BiSi-1 emerges as a nanocrystalline, anisotropic Bi–silicate whose connectivity, local Bi–O environment, and accessible texture are tunable by aging and post-treatments, positioning it as a promising platform for heterogeneous catalysis and environmental remediation.
KW - 29Si NMR
KW - Bismuth
KW - Silicate
PY - 2025
DO - https://doi.org/10.1007/s10853-025-11732-6
SN - 0022-2461
VL - 60
IS - 45
SP - 22615
EP - 22635
PB - Springer Science and Business Media LLC
AN - OPUS4-64755
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chahal, Shweta
T1 - Sustainable Synthesis of Na+ and Bi3+ - doped Cs₂AgInCl₆ Double Perovskites for Efficient White-Light Emission
N2 - Double halide perovskites have emerged as promising, less-toxic alternatives to lead-based perovskites for diverse photochemical applications. Among them, Cs₂AgInCl₆ has attracted significant attention, particularly when doped with various elements, which induce self-trapped exciton (STE) states within the bandgap, resulting in efficient white-light emission and a remarkable enhancement of photoluminescence quantum yield (PL QY). While several solid-state and solution-based methods have been employed for the synthesis of double halide perovskites, many rely on toxic solvents and complex procedures, hindering scalability. In this study, we present two environmentally friendly synthesis approaches for the preparation of Cs₂AgInCl₆ doped with monovalent (Na⁺) and trivalent (Bi³⁺) cations:
1. Green solution-based method: Utilizes mild reagents and entirely replaces harsh chemicals, enabling synthesis at ambient conditions.
2. Mechanochemical approach: Employs high-energy ball milling for 62 minutes at room temperature to obtain the desired crystalline phase.
These green methodologies provide sustainable and scalable alternatives to conventional routes, minimizing the environmental footprint. We systematically compare the structural and optical properties of the doped perovskites synthesized via both approaches. The resulting materials exhibit strong UV absorption, broadband white-light emission, high PL QY (up to 85%, Fig. 1), long PL lifetimes, and good thermal and environmental stability (up to 300 °C in air). These results highlight the potential of doped Cs₂AgInCl₆ double perovskites as an eco-friendly material with possible photonic applications as in white-light devices.
T2 - eMRS Fall Meeting 2025
CY - Warsaw, Poland
DA - 15.09.2025
KW - Fluorescence
KW - Advanced material
KW - Perovskite
KW - Synthesis
KW - Characterization
KW - Fluorescence quantum yield
KW - Absolute
KW - Integrating sphere spectroscopy
KW - Sustainable synthesis
KW - Lifetime
KW - Photophysics
PY - 2025
AN - OPUS4-64185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schraut, Katharina
T1 - Production of a hydraulic material from post-treated steelmaking slags
N2 - Steelmaking slag is a by-product of steel production of which 4.5 Mt were produced in 2020 in Germany alone. It is mainly used in road construction, earthwork and hydraulic engineering. A smaller part is returned to the metallurgical circle, used as fertilizer or landfilled.
With this use, iron oxides still contained in steelmaking slag are lost. In addition, the possibility of producing higher-grade products from steelmaking slag is foregone. In recent decades, many researchers have investigated the production of Portland cement clinker and crude iron from basic oxygen furnace slags (BOFS) via a reductive treatment. Carbothermal treatment of liquid BOFS causes a reduction of iron oxides to metallic iron, which separates from the mineral phase due to its higher density. Simultaneously, the chemical composition of the reduced slag is adapted to that of the Portland cement clinker.
In this study, German BOFS was reduced in a small-scale electric arc furnace using petrol coke as a reducing agent. The resulting low-iron mineral product had a similar chemical composition to Portland cement clinker and was rich in the tricalcium silicate solid solution alite (Ca3SiO5). Based on its chemical and mineralogical composition, similar to that of Portland cement clinker, the reduced BOFS has the potential to react comparably. In our study, the reduced BOFS produced less heat of hydration compared to OPC and its hydraulic reaction was delayed. However, adding gypsum has been shown to accelerate the hydration rate of the reduced BOFS compared to that known from the calcium silicates of Portland cement clinker.
Further research to improve the hydraulic properties of the reduced slag is essential. If successful, producing a hydraulic binder and crude iron from BOFS could have economic and ecological benefits for both the cement and steel industry.
T2 - 16th International Congress on the Chemistry of Cement ICCC 2023
CY - Bangkok, Thailand
DA - 18.09.2023
KW - Steelmaking slag
KW - Alite hydraulic reactivity
KW - Clinker substitute
PY - 2023
AN - OPUS4-58522
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bügel, Stefanie
A1 - Hähnel, Malte
A1 - Kunde, Tom
A1 - de Sousa Amadeu, Nader
A1 - Sun, Yangyang
A1 - Spieß, Alex
A1 - Beglau, Thi Hai Yen
A1 - Schmidt, Bernd M.
A1 - Janiak, Christoph
T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation
N2 - : A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,40-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,20,3,30,5,50,6,60-octafluoro 4,40
-biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM
KW - Separation
KW - COF
KW - MMM
KW - CO2
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618625
DO - https://doi.org/10.3390/ma15082807
VL - 15
IS - 8
SP - 2807
PB - MDPI
AN - OPUS4-61862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaki, Mohammad
A1 - Prinz, Carsten
A1 - Ruehle, Bastian
T1 - A Self-Driving Lab for Nano- and Advanced Materials Synthesis
N2 - The recent emergence of self-driving laboratories (SDL) and material acceleration platforms (MAPs) demonstrates the ability of these systems to change the way chemistry and material syntheses will be performed in the future. Especially in conjunction with nano- and advanced materials which are generally recognized for their great potential in solving current material science challenges, such systems can make disrupting contributions. Here, we describe in detail MINERVA, an SDL specifically built and designed for the synthesis, purification, and in line characterization of nano- and advanced materials. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. We further study the reproducibility and particle size distributions of these seven representative materials in depth and show the excellent performance of the platform when synthesizing these material classes. Lastly, we discuss the design considerations as well as the hardware and software components that went into building the platform and make all of the components publicly available.
KW - Self-driving laboratories
KW - Materials acceleration platforms
KW - Nanomaterials
KW - Advanced materials
KW - Automation
KW - Robotics
KW - In-line characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627361
DO - https://doi.org/10.1021/acsnano.4c17504
SN - 1936-086X
VL - 19
IS - 9
SP - 9029
EP - 9041
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-62736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kossatz, Philipp
A1 - Mezhov, Alexander
A1 - Andresen, Elina
A1 - Prinz, Carsten
A1 - Schmidt, Wolfram
A1 - Resch-Genger, Ute
T1 - Assessing the Applicability of Lanthanide-Based Upconverting Nanoparticles for Optically Monitoring Cement Hydration and Tagging Building Materials
N2 - Chemically stable, lanthanide-based photon upconversion micro- and nanoparticles (UCNPs) with their characteristic multicolor emission bands in the ultraviolet (UV), visible (vis), near-infrared (NIR), and short-wave infrared (SWIR) arepromising optical reporters and barcoding tags. To assess the applicability of UCNPs for the monitoring of early stage cement hydration processes and as authentication tags for cementitious materials, we screened the evolution of the luminescence of Selfmade core-only NaYF4:Yb,Er UCNPs and commercial μm-sized Y2O2S:Yb,Er particles during the first stages of cement hydration, which largely determines the future properties of the hardened material. Parameters explored from the UCNP side included particle size, morphology, surface chemistry or coating, luminescence properties, and concentration in different cement mixtures. From the cement side, the influence of the mineral composition of the cement matrix was representatively examined for ordinary Portland cement (OPC) and its constituents tricalcium aluminate (C3A), tricalcium silicate (C3S), and gypsum at different water to cement ratios. Based on reflection and luminescence measurements, enabling online monitoring, which were complemented by XRD and isothermal heat-flow calorimetric measurements to determine whether the incorporation of these particles could impair cement hydration processes, well suited lanthanide particle reporters could be identified as well as application conditions. In addition, thereby the reporter influence on cement hydration kinetics could be minimized while still preserving a high level of information content. The best performance for the luminescence probing of changes during early stage cement hydration processes was observed for 25 nm-sized oleate (OA)-coated UCNPs added in a concentration of 0.1 wt %. Higher UCNP amounts of 1.0 wt % delayed cement hydration processes size- and surface coatingspecifically in the first 24 h. Subsequent luminescence stability screening studies performed over a period of about one year support the applicability of UCNPs as optical authentication tags for construction materials.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - NIR
KW - Mechanism
KW - Characterization
KW - XRD
KW - Calorimetry
KW - Advanced material
KW - Cement
KW - Monitoring
KW - Surface
KW - Size
KW - Lifetime
KW - Barcode
KW - Lanthanide
KW - Upconversion
KW - Encoding
KW - Method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638318
DO - https://doi.org/10.1021/acsomega.5c02236
SN - 2470-1343
VL - 10
IS - 29
SP - 31587
EP - 31599
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-63831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chouquet, Xavier
A1 - Bolten, Julia
A1 - Prinz, Carsten
A1 - Günster, Jens
A1 - Zocca, Andrea
ED - Vincenzini, P.
T1 - Direct ink writing of zeolite-like AQSOA Z02 for envisioned applications in solar-driven atmospheric water harvesting: Paste formulation and effect of thermal treatments on the water sorption propertie
N2 - This work presents the development of porous water adsorbent bodies with complex geometries shaped by direct ink writing additive manufacturing. AQSOA FAM Z02 (Z02), a commercial material similar to SAPO-34 with chabazite structure, was selected as sorbent material. Dynamic vapor sorption analysis demonstrated that Z02 adsorbs and desorbs up to 30 % of its own mass in each cycle, highlighting its potential for this application. To optimize its printability for direct ink writing, aqueous pastes composed of Z02 and bentonite were formulated. Bentonite served as the inorganic binder and was responsible for the mechanical stability of the printed porous bodies after heat treatment. The most suitable paste composition was identified and used to fabricate scaffold structures. These structures were then subjected to different heat treatments at 650 °C, 750 °C and 850 °C to find a suitable compromise between mechanical stability and retention of the sorption properties. Scaffold structures printed with a 20 wt% of bentonite binder were mechanically stable (1.9 ± 1.1 MPa compressive strength) and retained a maximum water uptake of ca. 25 wt% after heat treatment at 750 °C for 1 h.
KW - Direct ink writing
KW - Zeolite
KW - Direct ink wriDynamic vapor sorption
KW - Bentonite Water harvesting
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643150
DO - https://doi.org/10.1016/j.ceramint.2025.09.314
SN - 0272-8842
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-64315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Knigge, Xenia
A1 - Ciornii, Dmitri
A1 - Reed, B.P.
A1 - Pollard, A.J.
A1 - Clifford, C.A.
A1 - Howe, T.
A1 - Vyas, N.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Influence of the Morphology on the Functionalization of Graphene Nanoplatelets Analyzed by Comparative Photoelectron Spectroscopy with Soft and Hard X-Rays
N2 - Since its isolation, graphene has received growing attention from academia and industry due to its unique properties. However, the “what is my material” barrier hinders further commercialization. X-ray photoelectron spectroscopy (XPS) is considered as a method of choice for the determination of the elemental and chemical composition. In this work the influence of the morphology of graphene particles on the XPS results is studied and investigated as a function of X-ray energy, using conventional XPS with Al K𝜶 radiation and hard X-ray photoemission spectroscopy (HAXPES) using Cr K𝜶 radiation. Thereby, the information depth is varied between 10 and 30 nm. For this purpose, two commercial powders containing graphene nanoplatelets with lateral dimensions of either ≈100 nm or in the micrometer range are compared. These larger ones exist as stack of graphene layers which is inspected with scanning electron microscopy. Both kinds of particles are then functionalized with either oxygen or fluorine. The size of the graphene particles is found to influence the degree of functionalization. Only the combination of XPS and HAXPES allows to detect the functionalization at the outermost surface of the particles or even of the stacks and to provide new insights into the functionalization process.
KW - Functionalized graphene
KW - Hard-energy X-ray photoelectron spectroscopy
KW - X-ray photoelectron spectroscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578860
DO - https://doi.org/10.1002/admi.202300116
SN - 2196-7350
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-57886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Terborg, R.
A1 - Kim, K. J.
A1 - Hodoroaba, Vasile-Dan
T1 - Elemental composition and thickness determination of thin films by electron probe microanalysis
N2 - Electron probe microanalysis (EPMA) applies to solid samples of homogenous (bulk) chemical composition and can usually not be applied to structures which are inhomogeneous in the micrometer range such as thin film systems down to a few nm. However, in combination with the established thin film software Stratagem, the thickness as well as the elemental composition of thin films on a substrate can be determined. This has been recently successfully demonstrated for Fe-Ni on Si and Si-Ge on Al2O3 thin film systems. For both systems five samples of different elemental composition and a reference were produced and characterised by inductively coupled plasma mass spectrometry (ICP-MS), Rutherford backscattering (RBS), and transmission electron microscopy (TEM) as reference values. Last year, a new and open-source thin film evaluation programme called BadgerFilm has been released. It can also be used to determine thin film composition and thickness from intensity ratios of the unknown sample and standards (k-ratios). In this contribution, we reevaluated the data acquired for the Fe-Ni and Si-Ge systems using the BadgerFilm software package and compared the obtained elemental compositions and thickness values with the results of the Stratagem software and the reference methods. The conclusion is that the BadgerFilm software shows good agreement with the elemental composition and thickness calculated by Stratagem (mostly <2% for both composition and thickness) and with the reference values for two representative thin film systems (<1%–2% for composition and <10%–20% for thickness).
KW - Elemental composition
KW - EPMA
KW - Film thickness
KW - Thin films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576368
DO - https://doi.org/10.1002/sia.7183
SN - 0142-2421
VL - 55
SP - 496
EP - 500
PB - Wiley
AN - OPUS4-57636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Bartczack, Dorota
A1 - Taché, Olivier
A1 - Hodoroaba, Vasile-Dan
T1 - Report on the homogeneity assessment of bimodal gold materials (nPSize1 and nPSize2) and particle number concentration by frequency method
N2 - The main objective was to assess homogeneity of two bimodal gold materials, namely nPsize1 and nPSize2, containing approximately 1:1 and 10:1 particle number-based ratio of ~30nm and ~60nm particles. Particle number-based concentration within the two size fractions was determined with spICP-MS using the particle frequency method of calibration.
KW - Nanoparticles
KW - Homogeneity
KW - Particle number concentration
KW - Gold
KW - nPSize
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595451
DO - https://doi.org/10.5281/zenodo.10654245
SP - 1
EP - 5
PB - Zenodo
CY - Geneva
AN - OPUS4-59545
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ankli, P. P.
A1 - Abdelwahab, A. A.
A1 - Logachov, A.
A1 - Bugiel, R.
A1 - Drobne, D.
A1 - Novak, S.
A1 - Kranjc, E.
A1 - Saje, S.
A1 - Pellegrino, F.
A1 - Alladio, E.
A1 - Sordello, F.
A1 - Corrao, E.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
A1 - Mrkwitschka, Paul
A1 - Madbouly, Loay Akmaal
A1 - Akdemir, Yücel
A1 - Gulumian, M.
A1 - Wepener, V.
A1 - Andraos, C.
A1 - Boodhia, K.
A1 - Jones, E.
A1 - Doolin, A.
A1 - Leuchtenberg, K.
A1 - Valsami Jones, E.
A1 - Rocca, C.
A1 - Ibrahim, B.
A1 - Singh, D.
A1 - Chakraborty, S.
A1 - Jurkschat, K.
A1 - Johnston, C.
A1 - Van Der Zande, M.
A1 - Fernandez, D.
A1 - Queipo, P.
A1 - Clifford, C.
A1 - Hardy, B.
T1 - Knowledge Infrastructure supporting image-based characterisation of 2D graphene materials
N2 - As part of the European Horizon ACCORDs project, advanced methods are being developed for the image-based characterisation of 2D nanomaterials. Given the complexity of this task, robust nd wellorganised data management is critical to ensuring high-quality outcomes. To support this, we have established a knowledge infrastructure that serves as the central repository for protocols, images and experimental data which are stored in a standardised, harmonised manner and in accordance with the FAIR principles – Findable, Accessible, Interoperable and Reusable and open science. This machine-readable framework enables the systematic and computationally automated correlation of image features with experimental descriptors, facilitating accurate material characterisation and transparent reporting which is all integrated in the ACCORDs KI.
KW - Graphene-related 2D materials (GR2M)
KW - 2D materials
KW - Knowledge infrastructure
KW - Characterisation
PY - 2025
DO - https://doi.org/10.1016/j.toxlet.2025.07.660
SN - 0378-4274
VL - 411
SP - S281
EP - S282
PB - Elsevier B.V.
AN - OPUS4-65061
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Other than spherical/monodisperse Towards real world NPs as candidate reference materials for traceable size measurements
N2 - By far most of the current nanoparticle (NP) research is dealing with (quasi-) spherical and/or monodisperse particles. However, many NPs used in industrial applications are rather aspherical and polydisperse. This inhomogeneity considerably hampers their characterization and, particularly, the accurate determination of the nanoparticle size. In order to overcome this problem and to promote the availability of standardized size measurement methods, it is crucial to develop and establish (candidate) reference materials with inhomogeneous size (distribution), aspherical shape as well as agglomerated or aggregated particles.
Therefore, a new set of NPs including Au-, SiO2 , and TiO2-particles is investigated. The range of properties comprises polydisperse spherical, bimodal spherical, rod-like, acicular, bipyramidal, sheet-like as well as cubic NPs. With respect to a good traceability of the measurements, size and size distributions of the candidate reference materials are determined using microscopic methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning electron microscopy in transmission mode (STEM-in-SEM), atomic force microscopy (AFM) as well as small angle X-ray scattering (SAXS) as an ensemble technique. The development of protocols for sample preparation is of particular importance to obtain a homogeneous dispersion of the NPs on a substrate. Further, approaches for signal modelling for all the methods above are being developed. The initiation of two VAMAS (www.vamas.org/twa34/index.html) inter-laboratory comparisons on bipyramidal titania and bimodal silica with different modal concentration ratios will be also highlighted.
T2 - E-MRS Spring Meeting 2021
CY - Online meeting
DA - 31.05.2021
KW - Nanoparticles
KW - Particle size distribution
KW - Imaging
KW - Traceability
KW - Reference material
PY - 2021
AN - OPUS4-52764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - EMPIR nPSize - Improved Traceability Chain of Nanoparticle Size Measurement; What nPSize can offer to CEN/TC 352?
N2 - The main outcomes of the EMPIR project nPSize are presented and the suitability of the new capabilities (e.g. reference materials, measurement procedures, inter-laboratory comparisons) as pertinent contributions to normative projects within CEN/TC 352 Nanotechnologies are discussed. E.g. the first technical report of nPSize on full algorithm sequences for nanoparticle detection and size measurement as developed on both a physical basis (SEM, TSEM, AFM and SAXS) and by machine learning is put at disposal.
T2 - 29th Meeting of CEN/TC 352 Nanotechnologies
CY - Online meeting
DA - 25.03.2021
KW - Nanoparticles
KW - Electron microscopy
KW - CEN/TC 352 Nanotechnologies
KW - Particle size distribution
KW - Modelling
KW - Machine learning
PY - 2021
AN - OPUS4-52464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Tour de table - BAM
N2 - Kurzübersicht über die neuen Aktivitäten zu Nanomaterialien in 2021.
T2 - Nano-Behördenklausur der Bundesoberbehörden 2021
CY - Online meeting
DA - 17.11.2021
KW - Nano
KW - Nanomaterial
KW - Nanopartikel
KW - Bundesoberbehörden
PY - 2021
AN - OPUS4-53827
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Schwerpunktthema nano@BAM – Projekt Nanoplattform
N2 - Darstellung der Digitalisierung im Rahmen des Themenfeldprojektes Nanoplattform. Es werden beleuchtet: BAM-DataStore, Voraussetzungen für ELNs, Möglichkeitenvon OpenBIS, NFDI-Antrag InnoMatSafety, Digitalisierung von Workflows.
T2 - BAM Beiratssitzung Umwelt
CY - Online meeting
DA - 11.03.2022
KW - Nano
KW - Elektronisches Laborbuch
KW - Workflows
KW - Digitalisierung
KW - Standardarbeitsanweisungen
PY - 2022
AN - OPUS4-56756
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Towards Interoperability: Digital Representation of a Material Specific Characterization Method
N2 - Certain metallic materials gain better mechanical properties through controlled heat treatments. For example, in age-hardenable aluminum alloys, the strengthening mechanism is based on the controlled formation of nanometer sized precipitates, which represent obstacles to dislocation movement. Precise tuning of the material structure is critical for optimal mechanical behavior in the application. Therefore, analysis of the microstructure and especially the precipitates is essential to determine the ideal parameters for the interplay of material and heat treatment. Transmission electron microscopy (TEM) is utilized to identify precipitate types and orientations in a first step. Dark-field imaging (DF-TEM) is often used to image the precipitates and to quantify their relevant dimensions.
The present work aims at the digital representation of this material-specific characterization method. Instead of a time-consuming, manual image analysis, an automatable, digital approach is demonstrated. Based on DF-TEM images of different precipitation states of a wrought aluminum alloy, a modularizable digital workflow for quantitative precipitation analysis is presented. The integration of this workflow into a data pipeline concept will also be discussed. Thus, by using ontologies, the raw image data, their respective contextual information, and the resulting output data from the quantitative precipitation analysis can be linked in a triplestore. Publishing the digital workflow and the ontologies will ensure the reproducibility of the data. In addition, the semantic structure enables data sharing and reuse for other applications and purposes, demonstrating interoperability.
The presented work is part of two digitization initiatives, the Platform MaterialDigital (PMD, materialdigital.de) and Materials-open-Laboratory (Mat-o-Lab).
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Interoperability
KW - Ontology
KW - Precipitation Analysis
PY - 2022
AN - OPUS4-55892
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Accuracy on all scales: Hybrid metrology for micro- and nanomanufacturing
N2 - In this presentation, we discuss hybrid metrology and correlative imaging. These techniques are used to improve the design and quality monitoring of nanomaterials used in energy technology and for referencing the properties of nanoparticles.
T2 - EMN for Advanced Manufacturing workshop
CY - Berlin, Germany
DA - 22.05.2024
KW - Nanotechnology
KW - Nanoanalytics
KW - Correlative Spectroscopy
KW - Correlative Imaging
PY - 2024
AN - OPUS4-60240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zia, Ghezal Ahmad Jan
T1 - Quantitative Precipitate Analysis of an Age-Hardenable Aluminium Alloy Using a Deep Learning Approach
N2 - Mechanical properties of metals and their alloys are strongly governed by their microstructure. The nanometer-sized precipitates in hardenable wrought aluminium alloys, which can be controlled by heat treatment, act as obstacles to dislocation movement within the material and are critical to the mechanical performance of the component, in this case a radial compressor wheel of a ships’ engine. TEM-based image analysis is essential for the study to investigate the microstructural changes (precipitation coarsening) that occur as a result of ageing at elevated temperatures.
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Aluminium Alloy
KW - Deep Learning
KW - TEM Image
PY - 2022
UR - https://dgm.de/mse/2022/
AN - OPUS4-55949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Aging processes in precipitation hardened aluminum alloys
N2 - The mechanical strength of wrought high-strength aluminum alloys is essentially based on precipitation hardening, possibly in combination with prior forming, e. g. by stretching. Important parameters for achieving an optimum combination of hardness, strength, ductility, toughness, and further properties such as corrosion resistance are age-hardening temperature and time.
During thermal (mechanical) treatment, nucleation and growth of precipitates takes place, leading to the desired degree of hardening. In aluminum alloys, precipitation sequences are usually passed through, i. e. a sequence of metastable precipitates is formed before the stable phase can precipitate. The optimum combination of properties is therefore based on a certain (optimum) microstructure, which can, however, change during the use of a component, since the microstructure is not stable. This happens in particular when the operating temperatures are close to the aging temperature and/or the operating times are sufficiently long. An external mechanical load may accelerate the processes. The presentation gives some examples for this.
T2 - Materials Science and Engineering Congress MSE 2022
CY - Darmstadt, Germany
DA - 27.9.2022
KW - Aluminium alloy
KW - Precipitation hardening
KW - Aging
KW - Degradation
PY - 2022
AN - OPUS4-55877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Reliable physico–chemical characterisation of graphene-related and other 2D materials: present and future
N2 - In the path of commercialisation of graphene-related and other 2D materials the consolidation has begun. In this phase, it is important to build trust between the individual partners in the product value chain. This requires trustworthy statements based on reliable and reproducible material characterisation. The first steps have been taken to measure graphene and other related 2D materials (GR2Ms) under well-defined conditions. Measurands and protocols for key methods were made available for this purpose. But there are still some challenges to overcome such as (i) reference materials, (ii) reference data, (iii) reproducibility throughout the workflow, (iv) credible structure-activity relationships, bringing the standards to (v) the factory floor and to (vi) real-word products. In addition, 2D materials beyond graphene should also be considered exploiting the knowledge gained from the characterisation of GR2M.
KW - 2D Materials
KW - Commercialisation
KW - Standardisation
KW - Trust
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638122
DO - https://doi.org/10.1088/2053-1583/aded9d
SN - 2053-1583
VL - 12
IS - 4
SP - 1
EP - 8
PB - IOP Publishing
AN - OPUS4-63812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, M. E.
A1 - Vickery, W. M.
A1 - Swift-Ramirez, W.
A1 - Arnold, A. M.
A1 - Orlando, J. D.
A1 - Schmidt, S. J.
A1 - Liu, Y.
A1 - Er, Jasmin
A1 - Schusterbauer, Robert
A1 - Ahmed, R.
A1 - Nickl, Philip
A1 - Radnik, Jörg
A1 - Donskyi, Ievgen
A1 - Sydlik, S. A.
T1 - The Mitsunobu reaction for the gentle covalent attachment of biomolecules to graphene oxide
N2 - Graphene oxide (GO) has emerged as a promising biomaterial as it is easily and cheaply synthesized, strong, cytocompatible, osteoinductive, and has a well-characterized aqueous degradation pathway. It is also a great substrate for functionalization with biomolecules such as proteins, peptides, and small molecules that can enhance or add bioactivity. Covalent chemical linkages as opposed to typical noncovalent association methods are preferable so that the biomolecules do not quickly diffuse away or face replacement by other proteins, which is critical in long time scale applications like bone regeneration. However, covalent chemistry tends to carry a drawback of harsh reaction conditions that can damage the structure, conformation, and therefore function of a delicate biomolecule like a protein. Here, the Mitsunobu reaction is introduced as a novel method of covalently attaching proteins to graphene oxide. It features gentle reaction conditions and has the added benefit of utilizing the plentiful basal plane alcohol functionalities on graphene oxide, allowing for high yield protein functionalization. The amino acid Glycine (G), the protein bovine serum albumin (BSA), and the small molecule SVAK-12 are utilized to create the three Mitsunobu Graphene (MG) materials G-MG, BSA-MG, and SVAK-MG that demonstrate the wide applicability of this functionalization method.
KW - Graphene oxide
KW - Mitsunobu reaction
KW - Covalent attachment
KW - Bovine serum albumin
KW - Macrophage polarization
KW - Osteogenesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630483
DO - https://doi.org/10.1016/j.carbon.2025.120221
VL - 238
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-63048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - XPS–SEM/EDS Tandem Analysis for the Elemental Composition of Functionalized Graphene Nanoplatelets
N2 - Over the past decade, energy-dispersive X-ray spectrometry (EDS) with scanning electron microscopy (SEM) has advanced to enable the accurate analysis of light elements such as C, N, or O. For this reason, EDS is becoming increasingly interesting as an analytical method for the elemental analysis of functionalized graphene and could be an attractive alternative to Xray photoelectron spectroscopy (XPS), which is considered the most important method for elemental analysis. In this study, comparative XPS and EDS investigations under different excitation conditions are carried out on commercially available powders containing graphene particles with different morphologies. The slightly different XPS/HAXPES and EDS results can be explained by the different information depths of the methods and the functionalization of the particle surfaces. For the material with smaller graphene particles and higher O/C ratios, all methods reported a lower O/C ratio in pellets compared with the unpressed powder samples. This clearly shows that sample preparation has a significant influence on the quantification results, especially for such a type of morphology. Overall, the study demonstrates that EDS is a reliable and fast alternative to XPS for the elemental quantification of functionalized graphene particles, provided that differences in the information depth are taken into account. Particle morphology can be examined in parallel with quantitative element analysis, since EDS spectrometers are typically coupled with SEM, which are available in a huge number of analytical laboratories.
KW - Graphene oxide
KW - SEM/EDS
KW - XPS/HAXPES
KW - Elemental composition
KW - Functionalization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647294
DO - https://doi.org/10.1021/acsomega.5c07830
SN - 2470-1343
SP - 1
EP - 7
PB - American Chemical Society (ACS)
AN - OPUS4-64729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, Francesco
A1 - Maurino, V.
A1 - Hodoroaba, Vasile-Dan
T1 - Morphological Characterization and Chemical Identification of TiO2 Nanoparticles Doped with Ultrafine Metal Particles for Enhanced Photocatalytical Activity
N2 - The conversion of solar energy into electricity and solar fuels is of crucial importance for a green and sustainable future. Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen (H2) fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, etc) and metal concentrations will be discussed.
KW - Nanoparticles
KW - Photocatalysis
KW - Electron microscopy
KW - EDS
KW - Metal-semiconductor
PY - 2022
DO - https://doi.org/10.1017/S1431927622010078
VL - 28
IS - Suppl. 1
SP - 2658
EP - 2660
PB - Cambridge University Press
AN - OPUS4-55436
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
T1 - How to test the Arrhenius validity of elastomers during ageing
N2 - The main task of the division "Safety of Storage Containers" at BAM is the safety assessment of storage containers for radioactive waste. A sufficient sealing of bolted lid systems for the safe containment of the waste for transport, storage and disposal is very important. Extensive knowledge of the change of the elastomer’s properties during ageing and the availability of reliable end-of-lifetime criteria is mandatory to guarantee long term safe enclosure.
In a long-term test programme over 5 years we have studied the degradation and the change of sealing properties of several elastomers, including EPDM, at four different ageing temperatures (75 °C, 100 °C, 125 °C and 150 °C). Compression stress relaxation (CSR) and compression set (CS) experiments were carried out. It has been found that when the data does not cover a sufficient time frame necessary for the evolution of the degradation of a chosen property, a curvature in the Arrhenius relationship is observed. For CSR, the curvature was observed for samples aged up to 186 days. As for CS experiments, the curvature was detected for sample aged up to 2 years. To cover the possible lack of experimental long-term data at low temperatures, a numerical model for CSR was developed and longer ageing times for the simulation were adopted. A degradation-rate based model for the evolution of degradative processes is proposed. The main advantage of the model is the possibility to quickly validate the interpolation at lower temperatures within the range of slower chemical processes without forcing an Arrhenius straight-line extrapolation. The model was also applied to CS experiments and validated by the 5 years experimental results where the curvature was gone, and the degradation property has followed an Arrhenius relationship. In the figure the contribution of the two degradative processes are shown over CS and CSR respectively.
T2 - 2nd advanced material science world congress
CY - Online meeting
DA - 14.06.2021
KW - Arrhenius
KW - Processes
KW - Compression set
KW - Compression stress relaxation
KW - Modelling
PY - 2021
AN - OPUS4-52825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voss, Heike
T1 - Picosecond laser processing of hierarchical micro-nanostructures on Ti-alloy upon pre- and post-anodization
N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser-processing step) plays an important role for the response of boneforming osteoblasts – an effect that can be utilized for improving permanent dental- or removable bone-implants. For exploring these different surface functionalities, multi-method chemical and structural characterizations were performed for two different characteristic micro-spikes covered by nanometric laserinduced periodic surface structures (LIPSS) on Ti-6Al-4V upon irradiation with nearinfrared ps-laser pulses (1030 nm wavelength, ~1 ps pulse duration, 66 & 80 kHz pulse repetition rate) at two distinct sets of laser fluence and beam scanning parameters. This involves morphological and topographical investigations by scanning electron microscopy (SEM) and white light interference microscopy (WLIM), near-surface chemical analysis by X-ray photoelectron spectroscopy (XPS) and hard X-ray photoelectron spectroscopy (HAXPES), as well as structural material examination via X-ray diffraction (XRD) measurements. The results allow to qualify the laser ablation depth, assess the spike geometry and surface roughness parameters, and provide detailed insights into the near-surface oxidation that may cause the different cell growth behavior for pre- or post-anodized medical implants.
T2 - E-MRS Spring Meeting 2023
CY - Strasbourg, France
DA - 29.05.2023
KW - Hard X-ray photoelectron spectroscopy (HAXPES)
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ti6Al4V alloy
KW - Hierarchical micro-nanostructures
KW - Ultrashort laser processing
PY - 2023
AN - OPUS4-60344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Report ISO/TC202/WG4 X-Ray Spectroscopy, Liaisons with VAMAS and ISO/TC229 Nanotechnologies
N2 - The presentation is structured in the following three parts:
i) Report of the Working Group 4 X-Ray Spectroscopy including the publication of ISO 15632:2021 Microbeam analysis — Selected instrumental performance parameters for the specification and checking of energy-dispersive X-ray spectrometers for use in electron probe microanalysis,
ii) Liaison activities between ISO/TC202 Microbeam Anaylsis and VAMAS/TWA34 Quantitative Microstructural Analysis, and
iii) Liaison activities from ISO/TC202 Microbeam Analysis for ISO/TC229 Nanotechnologies.
Most relevant projects are highlighted for information and further discussions. New initiatives and better promotion of strategic projects are addressed.
T2 - Annual Meeting of ISO/TC 202 Microbeam Analysis
CY - Online meeting
DA - 25.10.2021
KW - Microbeam Analysis
KW - VAMAS
KW - ISO/TC 202
KW - ISO/TC 229
KW - electron microscopy
KW - X-Ray Spectroscopy
KW - EBSD
KW - FIB
PY - 2021
AN - OPUS4-53625
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - EMPIR nPSize - Improved Traceability Chain of Nanoparticle Size Measurement; nPSize offer after 2 Ys
N2 - The main outcomes of the EMPIR project nPSize are presented and the suitability of the new capabilities (e.g. reference materials, measurement procedures, VAMAS inter-laboratory comparisons) to be standardized and implemented in accredited analytical laboratories is discussed.
T2 - EMPIR nPSize Training Course "Metrology for Measurement of Nanoparticle Size by Electron Microscopy and Atomic Force Microscopy"
CY - Online meeting
DA - 27.10.2020
KW - Nanoparticles
KW - Size
KW - Shape
KW - Traceability
KW - EMPIR
KW - Reference materials
KW - VAMAS
PY - 2020
AN - OPUS4-51477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weber, Mike
T1 - Coefficients of Friction in Dependence on Aging State of Elastomers – Experimental Identification and Numerical Simulation of the Experiment
N2 - Elastomer seals are mounted as barrier seals in lid systems of containers designed for transport and disposal of negligible heat generating radioactive waste and as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). When the behavior of mounted seals under normal and hypothetical accident conditions of disposal and transport is to be simulated, a comprehensive knowledge of their complex mechanical properties at every state of aging is necessary. In previous works, BAM’s efforts in experimental investigations on specimen artificially aged at different temperatures and times and the implementation of the found results in finite element material models were presented. Additionally, our approaches to reproduce the aging process itself and to extrapolate the results of artificially accelerated aging to longer times were presented. Numerical simulations have shown that the behavior of the seal during mounting and one-sided pressurizing and the resulting performance values such as leakage rate strongly depend on the coefficient of friction (COF) between flange and seal. The friction coefficient, in turn, depends on the aging state of the elastomer material as several publications suggest (see below).
Dynamic COF between an exemplary ethylene propylene diene rubber (EPDM) material and a stainless steel ball were determined by using a self-designed linear oscillation tribometer. Unaged and artificially aged EPDM specimen stored for 30 days and 100 days at a temperature of 150 °C were tested. A stainless steel ball (d=10 mm) is brought in contact with the specimen’s surface und loaded by normal forces of 2.5 N, 5 N, 10 N and 20 N. During a reciprocating movement of the EPDM sheet, the horizontal force/friction force is continuously measured, and the COF can be derived.
It is well known that friction is a complex phenomenon especially in soft materials. It cannot be excluded that the measured friction force is influenced by additional force components, resulting from the ball’s grooving through the elastomer’s surface. This force depends on the penetration depth of the ball and on the resistance of the elastomer in its different states of aging. The latter results from microstructural changes i.e., chain scission and additional crosslinking that occur during aging which in turn influence the softening or hardening of the material.
A finite element (FE) ABAQUS® model was developed to reproduce the measurement process. It should help to better understand the physical mechanisms and to quantify the percentage of measured forces resulting from real friction on the one hand and forces resulting from unintended side effects that could falsify the result on the other hand. The behavior of the elastomer in its different states of aging is reproduced by a FE material model already presented in previous works of BAM.
T2 - ASME 2022 Pressure Vessels & Piping Conference (PVP2022)
CY - Las Vegas, NV, USA
DA - 17.07.2022
KW - Radioactive Waste
KW - Elastomers
KW - Aging
KW - Experiment
KW - Seal Behavior
KW - Numerical Simulation
KW - Leakage Rate
KW - Coefficient of Friction
PY - 2022
AN - OPUS4-57095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Morpho-Chemical Characterisation of Me-TiO2 Nanoparticles for Enhanced Photocatalytical Activity
N2 - The conversion of solar energy into electricity and solar fuels is of crucial importance for a green and sustainable future. Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen (H2) fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, etc) and metal concentrations will be discussed.
T2 - ECASIA 2022
CY - Limerick, Ireland
DA - 29.05.2022
KW - Titania nanoparticles
KW - Photocatalysis
KW - Scanning electron microscopy
KW - Energy dispersive X-ray spectroscopy
PY - 2022
AN - OPUS4-54977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Testing the quality of nanomaterial properties data for nano-risk assessment – towards guidance for all types of users
N2 - Data quality is a vast term, which comprises the completeness, relevance (adequacy), and reliability of data. So far, many attempts to assure data quality have been pursued, and evaluation criteria for data quality have been established. One relatively novel but already well-known aspect of data quality refers to the concept of data FAIRness, which states that data should be: findable, accessible, interoperable and re-usable. In order to find, use, and access data, a user has to be guided properly. Such guidelines already exist for regulators and the scientific community. However, a ‘simple’ non-academic user from general society is very unlikely to be able to access or understand such data. Our objective in the H2020 project NANORIGO is to help and guide all types of users (i.e., scientists, regulators, industry workers, citizens, etc.) to access and make use of high-quality data and information from available and suitable data repositories in order to increase the transparency of and trust in nanotechnology.
T2 - nanoSAFE 2020
CY - Online Meeting
DA - 16.11.2020
KW - Nano-related data
KW - Nanomaterial properties
KW - Nano-risk assessment
PY - 2020
AN - OPUS4-51701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Zurutuza, Amaia
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Standardized Chemical Composition Analysis of Graphene Oxide Flakes with SEM/EDS and XPS Works Reliably
N2 - Suspensions of graphene-related 2D materials (GR2M) are broadly used for further applications like printable electronics. The reliable quantification of the composition of graphene-related 2D materials as liquid suspensions is still a challenging task, which can hinder the commercialisation of the products. Specific parameters to be measured are defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present, but reference protocols are still missing. One of the central methods for the quantification is X-ray photoelectron spectroscopy (XPS) as a rather expensive method. Therefore, the development of cheaper alternatives is highly desired. One attractive alternative of XPS is energy-dispersive spectroscopy (EDS) which is usually coupled with scanning electron microscopy (SEM). This combination is one of the most widely used methods in analytical laboratories. In this contribution the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material are presented. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis, which has been carried out on the same samples.
It is demonstrated that for samples prepared by drop-casting on a substrate, both surface-sensitive XPS analysis and bulk-characterising EDS result in very similar elemental composition of oxygen and carbon for thick spots. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. The last results clearly show the influence of the substrate on the analysis of the results and stressed out the importance of the sample preparation.
KW - EDS
KW - Light elements
KW - XPS/HAXPES
KW - Graphene oxide
KW - Quantification
KW - Standardisation
PY - 2025
DO - https://doi.org/10.1093/mam/ozaf048.267
VL - 31
IS - 7
SP - 531
EP - 532
PB - Oxford Aacademic
AN - OPUS4-63792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Advanced Characterization of the Surface Morphology and Chemistry within nano@BAM
N2 - Both essential aspects of the surface of solid matter, its morphology and chemistry, are studied traditionally at BAM starting in the 60’s with different cyclical research focus areas, mostly related either to applicative research or method development. In the recent years, the focus has shifted almost exclusively to the nano-analytics of advanced materials such as complex nanoparticles, (ultra)thin films/coatings, nanocomposites, 2D materials, energy materials, etc. This is also the reason why BAM has established recently the new Competence Center nano@BAM (www.bam.de/Navigation/DE/Themen/Material/Nanotechnologie/sichere-nanomaterialien.html) with the five sub-fields nanoCharacterisation, nanoMaterial, nanoSafety, nanoData and nanoTechnology. The link to the BAM central guidelines to the safety in technology and chemistry is given by the development of reference products such as reference measurement procedures, reference (nano)materials, and newly reference data sets. Thus, an internationally well-networked group in surface analysis has been established @BAM, with regular contributions to integral analytical characterization with metrological and standardization background.
Examples of newly developed methodical approaches will be given with an emphasis on correlative nano-analysis of morphology and chemistry of nanomaterials. Correlative imaging by STEM-in-SEM with high-resolution SEM and EDX, and further with AFM or the new technique TKD (Transmission Kikuchi Diffraction) will be explained on various examples of nanostructures, both as starting materials and embedded/functionalized nanoparticles in products. The unique analytical benefits of the Auger electron probe as a veritable nano-tool for surface chemistry will be highlighted. The panoply of advanced surface characterization methods @BAM is completed by discussing examples of hybrid analysis of the bulk of nanomaterials by X-ray Spectroscopy with the highest surface-sensitive methods X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Particularly for the analysis of the surface chemistry of nanostructures, such as the completeness of the shells of core-shell nanoparticles or in-depth and lateral gradients of chemistry within mesoporous thin layers, the latter methods are inherent.
Other special developments like approaches for the quantitative determination of the roughness of particle surface by electron microscopy or for the quantitative determination of the porosity of thin mesoporous layers by electron probe microanalysis (EPMA) with SEM will be presented in conjunction with the corresponding advanced materials studied.
Current research projects, promising ideas, including ongoing (pre-)standardization activities in the field of the challenging nano/surface analysis will be touched systematically, with the open goal of identifying future bilateral cooperation possibilities between EMPA and BAM.
T2 - EMPA-Kolloquium
CY - Online meeting
DA - 01.12.2021
KW - Nanoparticles
KW - Nano@BAM
KW - Nanomaterials
KW - Surface morphology and chemistry
KW - Correlative analysis
PY - 2021
AN - OPUS4-54039
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Ongoing VAMAS interlaboratory comparisons on nanoparticles size and shape as pre standardisation projects for harmonized measurements
N2 - Traceable morphological and chemical characterization of nanomaterials with respect to the various possible sizes, size distributions, shapes, and concentrations of real-world nanoparticles (NPs) is a challenging task. Particularly for the nonspherical, non-monodisperse nanoparticles – as typically for most of the commercial particles, including their strong tendency to agglomerate, there is a lack of standard operation procedures providing accurate nanoparticle characterisation.
In the framework of the pre-standardisation framework of VAMAS (Versailles Project on Advanced Materials and Standards, www.vamas.org) two interlaboratory comparison (ILC) studies are being carried out under the Technical Working Area (TWA) 34 “Nanoparticle Populations”:i) Project #15 addresses the analysis of the size and shape distribution of TiO2 bipyramidal NPs by traceable imaging methods such as TEM, SEM, STEM-in-SEM, AFM as well as with SAXS as an ensemble method. This ILC is thought as the next level development of the case studies exemplified in the published ISO standards ISO 21363 and ISO 19749. It was agreed to complete the first ILC with the NPs already prepared according to the same procedure on a TEM grid, and, at a later stage, to carry out second ILCs with the same NPs distributed to the participants as liquid suspensions together with protocols for the uniform NP deposition on suited substrates - as developed and optimized within the European project nPSize. Once having good deposition protocols available, the door for automated image analysis gets opened. Corresponding image analysis protocols and reporting templates have been distributed to the ILC participants, too.
ii) Project #16: two spherical SiO2 NP samples with bi-modal size distributions in two nominal relative number concentrations were prepared and distributed also as liquid suspensions accompanied by sample preparation, measurement, and image analysis protocols and reporting templates. Here, the NP concentration is the primary parameter to be measured. For the imaging methods it is targeted to
measure the relative nanoparticle concentrations (relative populations of the two modes).
The results of all the participating laboratories, in both ILCs, compiled in comparative representations will be shown and discussed for the first time. The reduction of the measurement uncertainties associated to the size, shape and number-concentration results induced by the significant improvement of the sample preparation on substrates (as single particles with a high-density coverage), combined with welldefined image analysis procedures will be highlighted.
T2 - 2024 Spring Meeting of the European Materials Research Society (E-MRS)
CY - Strasbourg, France
DA - 27.05.2024
KW - VAMAS
KW - Interlaboratory comparison
KW - Electron microscopy
KW - Particle size distribution
KW - Article concentration
PY - 2024
AN - OPUS4-60184
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Knigge, Xenia
T1 - Complementary Analysis of Sterilized Nanoparticles with SEM/EDS And XPS/HAXPES
N2 - Since there is a lack of knowledge about the effects of nanomaterials on human health and the environment, and in order to get safe- and sustainable-by-design nanomaterials, it is necessary to find an easy way to assess their properties, without having to perform time-consuming experiments each time. In the European project NanoSolveIT, the behavior of nanoparticles is to be derived from a nanomaterial fingerprint database with standardized physico-chemical properties of nanomaterials. The key element for these grouping and reading across approaches is the collection of standardized information about nanomaterials in combination with modelling and simulations. As parameters the particle size, particle shape, chemical composition and surface chemistry are discussed here.
Measurements of the shape and size were performed using scanning electron microscopy (SEM). For the chemical composition energy dispersive X-ray spectroscopy (EDS) and for the surface chemistry X-ray photoelectron spectroscopy (XPS) were used. As an additional method hard X-ray photoelectron spectroscopy (HAXPES) with a higher information depth than XPS was used, thus we were able to include information not only from the top surface, but also from deeper regions of about 30 nm. Therefore, this method is complementary to EDS.
All these methods have been correlatively used to study nanoparticles of different chemical composition that have been treated differently by sterilization. Such a sterilization step is common, before testing for toxicity. To date, the sterilization step has not been considered in establishing the structure-activity relationship of the nanomaterial.
The effects of sterilization are discussed on exemplary samples. The results demonstrate the influence of sterilization on all investigated properties, indicating a restructuring of the nanoparticles. This implies that samples that have been sterilized after synthesis, may show different toxicity from those used in applications without a sterilization step.
Acknowledgement: This research is part of the project “NanoSolveIT”, which has received funding from European Union Horizon 2020 Programme (H2020) under grant agreement no 814572. (https://nanosolveit.eu/)
T2 - nanoSAFE'23
CY - Grenoble, France
DA - 04.06.2023
KW - XPS
KW - HAXPES
KW - Characterization
KW - Nanoparticles
KW - NanoSolveIT
PY - 2023
AN - OPUS4-57658
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterile Fe3O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterile Fe3O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Fe3O4
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7990301
PB - Zenodo
CY - Geneva
AN - OPUS4-57764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Radnik, Jörg
T1 - BAM reference data - XPS raw data of Al-coated titania nanoparticles (JRCNM62001a and JRCNM62002a)
N2 - XPS raw data of Al-coated titania nanoparticles (JRCNM62001 and JRCNM62002a) provided by the JRC repository are provided.
KW - XPS
KW - Titania nanoparticles
KW - BAM reference data
PY - 2021
DO - https://doi.org/10.5281/zenodo.4986068
PB - Zenodo
CY - Geneva
AN - OPUS4-52880
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - 1-Propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (Solarpur®) analyzed by hard x-ray photoelectron spectroscopy
N2 - 1-Propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (Solarpur®), an ionic liquid was purchased from Merck (formerly Sigma Aldrich), was analyzed using hard x-ray photoelectron spectroscopy (HAXPES). The liquid is UHV stable, vertically and laterally homogeneous, and is easy to clean; thus, it can be used as a reference material. The HAXPES spectra of Solarpur® obtained using monochromatic Cr Kα radiation at 5414.8 eV include a survey scan, high-resolution spectra of C 1s, O 1s, N 1s, S 2p, S 1s, S 2s, F 1s, and S KLL.
KW - HAXPES
KW - Hard x-ray photoelectron spectroscopy
KW - Ionic liquid
KW - Solarpur
PY - 2021
DO - https://doi.org/10.1116/6.0001414
VL - 28
IS - 2
SP - 1
EP - 8
PB - AVS: Science & Technology of Materials, Interfaces, and Processing
AN - OPUS4-54113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - VAMAS-Enabling international standardisation for increasing the take up of Emerging Materials
N2 - VAMAS (Versailles Project on Advanced Materials and Standards) supports world trade in products dependent on advanced materials technologies by providing technical basis for harmonized measurements, testing, specification, reference materials and standards. The major tools for fulfilling this task are interlaboratory comparisons (ILC). The organisation structure of VAMAS is presented. It is discussed, how a new technical activity can initiate.
T2 - DIN NA062-08-16 Oberflächenanalytik Frühjahrstreffen
CY - Berlin, Germany
DA - 11.05.2022
KW - Advanced Materials
KW - Standards
KW - Interlaboratory Comparisons
PY - 2022
AN - OPUS4-54831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - ISO-G-Scope Standardisation of structural and chemical properties of graphene
N2 - The objectives and tasks of the EMPIR project ISO-G-Scope are presented. The last results was shown. Esspecially, the interlaboratory comparison about XPS of functionalized graphene is presented.
T2 - DIN NA062-08-16 Oberflächenanalytik Frühjahrstreffen
CY - Berlin, Germany
DA - 11.05.2022
KW - Graphene
KW - Standardization
KW - Structural characterisation
KW - Chemical composition
PY - 2022
AN - OPUS4-54834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Xps/Haxpes at (core shell) nanoparticles
N2 - The principles of (Hard) X-ray photoelectron spectroscopy and some application in the field of (core-shell) nanoparticles will be presented. The presentation should answer hoe to get reliable results. Furthermore, examples of the correlation between physical-chemical measurments and toxicological results are given which are crucial for the risk assessment of nanoparticles.
T2 - Training Course Metrological Determination of Micro and Nano Contaminants in Food
CY - Berne, Switzerland
DA - 05.09.2023
KW - X-ray photoelectron spectroscopy
KW - Core-shell nanoparticles
KW - Reliabiilty
KW - Risk assessment
PY - 2023
AN - OPUS4-59496
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Colours, nano and surface
N2 - The basic ideas of colours and pigments are presented. The correlation between nanomaterials and colours are explained. Different methods are presented for investigating nanoparticles and their surface. At the end a case study is presented explaining the importance of coating for the properties of nanoparticles.
T2 - Eingeladener Vortrag im Deutschen Lackmuseum (Münster)
CY - Online meeting
DA - 11.02.2022
KW - Pigments
KW - Surface Analytics
KW - Coatings
PY - 2022
AN - OPUS4-54376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized AlOOH nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized AlOOH nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - AlOOH
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7966245
PB - Zenodo
CY - Geneva
AN - OPUS4-57757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hahn, Marc Benjamin
T1 - The change of DNA AND PROTEIN radiation damage upon hydration: In-situ observations by near-ambient-pressure XPS
N2 - X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS experiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. Our results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.
T2 - Dyson Conference 2023
CY - Prague, Czech Republic
DA - 24.04.2023
KW - Base damage
KW - Base loss
KW - Cancer treatment
KW - DNA
KW - DNA radiation damage
KW - Direct damage
KW - Dissociative electron attachment (DEA)
KW - Dissociative electron transfer (DET)
KW - Dosimetry
KW - Double-strand break (DSB)
KW - ESCA
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Hydrated DNA
KW - Hydrated electron
KW - Hydration shell
KW - Hydroxyl radical
KW - Indirect damage
KW - Ionization
KW - Ionisation
KW - LEE
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - NAP-XPS
KW - Near ambient pressure xray photo electron spectroscopy
KW - Net-ionization reaction
KW - OH radical
KW - PES
KW - Particle scattering
KW - Prehydrated electron
KW - Presolvated electron
KW - Quasi-direct damage
KW - ROS
KW - Radiation damage
KW - Radiation therapy
KW - Radical
KW - Radiolysis
KW - Radiotherapy
KW - Reactive oxygen species
KW - Simulation
KW - Single-strand break (SSB)
KW - TOPAS
KW - TOPAS-nbio
KW - XPS
KW - Xray
KW - Xray photo electron spectrocopy
KW - G5P
KW - Protein
KW - Single-stranded DNA-binding proteins
PY - 2023
AN - OPUS4-57406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Reusable data: putting the “Arr” in FAIR
N2 - This talk demonstrates how to apply FAIR principles to data from actual scientific investigations. The reasons and practical benefits of FAIR data are highlighted. Several levels of reusability are discussed, i.e. the “trust me”-level, the “I’ll not need to repeat my measurement”-level, and the “you’ll not need to repeat my measurements”-level. Practical FAIR datafiles are explored and their information content highlighted.
T2 - Reusability of Scientific Data for Matter
CY - Online meeting
DA - 13.11.2025
KW - Methodology
KW - Metadata
KW - FAIR
KW - Reusability
KW - X-ray scattering
KW - Traceability
PY - 2025
AN - OPUS4-65309
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
A1 - Marcoulaki, E.
A1 - van Duuren, B
T1 - Testing and benchmarking nanosafety services
N2 - One of the objectives of the EU Project EC4SafeNano (European Centre for Risk Management and Safe Innovation in Nanomaterials & Nanotechnologies) was to test and benchmark the services in order to check their relevance to address identified stakeholder needs, but also to evaluate the governance of the structure delivering the proposed services. The aim is to demonstrate the technical relevance of the services and the overall open structure organisation, including governance rules and operating procedures, by answering relevant identified questions (case studies) selected by a panel of stakeholders. Therefore, a significant part of the project will be devoted to this demonstration of the operational and functional basis of the organized network.
T2 - Review Meeting EC4SafeNano
CY - Brussels, Belgium
DA - 16.01.2020
KW - Nanosafety
KW - EC4SafeNano
KW - Nanosafety services
KW - EU
KW - Case studies
PY - 2020
AN - OPUS4-50273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weber, Mike
A1 - Zaghdoudi, Maha
A1 - Brandt, Guido
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Coefficients of Friction in Dependence on Aging State of Elastomers – Experimental Identification and Numerical Simulation of the Experiment
N2 - Elastomer seals are mounted as barrier seals in lid systems of containers designed for transport and disposal of negligible heat generating radioactive waste and as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). When the behavior of mounted seals under normal and hypothetical accident conditions of disposal and transport is to be simulated, a comprehensive knowledge of their complex mechanical properties at every state of aging is necessary. In previous works, BAM’s efforts in experimental investigations on specimen artificially aged at different temperatures and times and the implementation of the found results in finite element material models were presented. Additionally, our approaches to reproduce the aging process itself and to extrapolate the results of artificially accelerated aging to longer times were presented. Numerical simulations have shown that the behavior of the seal during mounting and one-sided pressurizing and the resulting performance values such as leakage rate strongly depend on the coefficient of friction (COF) between flange and seal. The friction coefficient, in turn, depends on the aging state of the elastomer material as several publications suggest (see below).
Dynamic COF between an exemplary ethylene propylene diene rubber (EPDM) material and a stainless steel ball were determined by using a self-designed linear oscillation tribometer. Unaged and artificially aged EPDM specimen stored for 30 days and 100 days at a temperature of 150 °C were tested. A stainless steel ball (d=10 mm) is brought in contact with the specimen’s surface und loaded by normal forces of 2.5 N, 5 N, 10 N and 20 N. During a reciprocating movement of the EPDM sheet, the horizontal force/friction force is continuously measured, and the COF can be derived.
It is well known that friction is a complex phenomenon especially in soft materials. It cannot be excluded that the measured friction force is influenced by additional force components, resulting from the ball’s grooving through the elastomer’s surface. This force depends on the penetration depth of the ball and on the resistance of the elastomer in its different states of aging. The latter results from microstructural changes i.e., chain scission and additional crosslinking that occur during aging which in turn influence the softening or hardening of the material.
A finite element (FE) ABAQUS® model was developed to reproduce the measurement process. It should help to better understand the physical mechanisms and to quantify the percentage of measured forces resulting from real friction on the one hand and forces resulting from unintended side effects that could falsify the result on the other hand. The behavior of the elastomer in its different states of aging is reproduced by a FE material model already presented in previous works of BAM.
T2 - ASME 2022 Pressure Vessels & Piping Conference (PVP2022)
CY - Las Vegas, NV, USA
DA - 17.02.2022
KW - Numerical Simulation
KW - Radioactive Waste
KW - Elastomers
KW - Aging
KW - Seal Behavior
KW - Leakage Rate
KW - Coefficient of Friction
KW - Experiment
PY - 2022
SP - 1
EP - 8
PB - American Society of Mechanical Engineers (ASME)
CY - New York, NY, USA
AN - OPUS4-57093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Standardized Chemical Characterisation of Graphene Oxide Flakes
by X-Ray Photoelectron Spectroscopy and Energy-Dispersive X-Ray
Spectroscopy
N2 - Reliable quantification of the chemical composition of graphene-related 2D materials as powders and liquid suspensions is a challenging task. Analytical methods such as XPS, ICP-MS, TGA and FTIR are recommended to be used in ongoing projects at standardisation bodies. The specific parameters to be measured are also defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present [1]. In this contribution, for the first time, the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material [2] are presented. It is expected that the quantitative EDS analysis of light elements emitting characteristic X-ray lines below 1 keV to be provided with significantly larger measurement uncertainties than the analysis of elements with an atomic number of 11 (Na) or above [3]. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis [4], which has been carried out on the same samples.
A crucial step in sample preparation from liquid suspension with graphene oxides flakes onto a substrate for analysis with both XPS and EDS. It is demonstrated that if a closed and enough thick drop-cast deposited spot is succeeded to be deposited on a substrate, both surface-sensitive XPS analysis and bulk-characterising EDS result in very similar elemental composition of oxygen and carbon. Hence, theoretical, expected O/C atomic ratio values for pure graphene oxide of ~0.5 [1] are achieved (with both methods), see Figure 1. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. To note that all the EDS results in this study have been quantified standardless.
The results of this study demonstrate the reliability of the reference measurement protocol for SEM/EDS to be introduced into ISO/DTS 23359, including the dedicated sample preparation, particularly for the cases when the concentration of the GO flakes in stock liquid suspension is low. Further, also the consideration of this GO material as one of the very few available as a commercial material on the market as the very first GO reference material with regard to its morphology as well as chemical composition. Both the standard measurement procedure and the candidate reference material will immensely contribute to characterise reliably the chemical composition of graphene-related 2D materials with SEM/EDS as one of the most widely used methods in analytical laboratories
T2 - EMAS 2025 Workshop
CY - Mataró, Spain
DA - 11.05.2025
KW - Advanced Materials
KW - Graphene
KW - Chemical Quantification
KW - EDX
KW - XPS
PY - 2025
AN - OPUS4-64082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dhamo, Lorena
A1 - Wegner, Karl David
A1 - Würth, Christian
A1 - Häusler, I.
A1 - Hodoroaba, Vasile-Dan
A1 - Resch-Genger, Ute
T1 - Assessing the influence of microwave-assisted synthesis parameters and stabilizing ligands on the optical properties of AIS/ZnS quantum dots
N2 - Luminescent semiconductor quantum dots (QDs) are frequently used in the life and material sciences as reporter for bioimaging studies and as active components in devices such as displays, light-emitting diodes, solar cells, and sensors. Increasing concerns regarding the use of toxic elements like cadmium and lead, and hazardous organic solvents during QD synthesis have meanwhile triggered the search for heavy-metal free QDs using green chemistry syntheses methods. Interesting candidates are ternary AgInS2 (AIS) QDs that exhibit broad photoluminescence (PL) bands, large effective Stokes shifts, high PL quantum yields (PL QYs), and long PL lifetimes, which are particularly beneficial for applications such as bioimaging, white light-emitting diodes, and solar concentrators. In addition, these nanomaterials can be prepared in high quality with a microwave-assisted (MW) synthesis in aqueous solution. The homogeneous heat diffusion and instant temperature rise of the MW synthesis enables a better control of QD nucleation and growth and thus increases the batch-to-batch reproducibility. In this study, we systematically explored the MW synthesis of AIS/ZnS QDs by varying parameters such as the order of reagent addition, precursor concentration, and type of stabilizing thiol ligand, and assessed their influence on the optical properties of the resulting AIS/ZnS QDs. Under optimized synthesis conditions, water-soluble AIS/ZnS QDs with a PL QY of 65% and excellent colloidal and long-term stability could be reproducible prepared.
KW - Quantum dots
KW - Microwave-assisted synthesis
KW - AgInS
KW - Aqueous synthesis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567091
DO - https://doi.org/10.1038/s41598-022-25498-3
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 11
PB - Nature Publishing Group
CY - London
AN - OPUS4-56709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Standardized workflow for checking the performance of an EDS X-ray spectrometer at a Scanning Electron Microscope
N2 - For test laboratories operating under accreditation schemes like ISO/IEC 17025 (ISO/IEC 17025), as the international reference for testing and calibration laboratories wanting to demonstrate their capacity to deliver reliable results, a periodical control of the critical instrumental parameters of an Energy-Dispersive X-ray Spectrometer (EDS) is required.
This periodical check of an EDS is specified with exact procedures and materials in the ISO 15632:2021 ”Microbeam Analysis – Selected instrumental performance parameters for the specification and checking of energy-dispersive X-ray spectrometers for use in electron probe microanalysis” (ISO 15632). The EDS check can be simplified to the acquisition of only one 10 kV spectrum from a dedicated test material, EDS-TM002, which is made available by BAM since 2009 (https://webshop.bam.de/webshop_en/). The optional BAM software “EDX spectrometer check” is destined to automatically evaluate this spectrum and determine the performance of the EDS in terms of energy resolution and calibration, as well as possible alteration of low-energy efficiency due to detector contamination. Nearly 200 laboratories have the EDS-TM and associated software package in use.
Practical examples based on various types of artifacts occurred in the EDS spectra and a long-term (>10 years) meticulous observation of the own spectrometers will be discussed. Different types of EDS spectrometers are considered, e.g. Si(Li) and SDD, of various window types (AP, the recent one Si3N4 or even windowless), and with different front contact layers (Au and Ni) (Hodoroaba and Procop, 2014). Evaluation of other parameters or effects such as the deadtime at different count rates or pileup effects is also explained with examples.
T2 - Workshop "Automated Mineralogy" @ GEOANALYSIS 2022
CY - Freiberg, Germany
DA - 06.08.2022
KW - EDS
KW - X-ray spectrometer
KW - Performance check
KW - Test material
KW - Standardized check
KW - EDS-TM002
PY - 2022
UR - https://geoanalysis2021.de/en/workshops/automated-mineralogy
AN - OPUS4-55460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Wire-print procedure for accurate morphological and Chemical characterization of graphene-related 2D-materials
N2 - One of the biggest challenges in the physico-chemical characterization of particulate nanomaterials pertains to the sample preparation. Particularly the imaging methods require suitable deposition of the sample on a substrate. ‘Suitable’ sample preparation of a particulate (nano)material on a substrate means to make visible the constituent particles to a microscopy technique able to analyze the nanoscale (AFM, SEM, TEM, etc). The particles deposited on a substrate either directly as a powder or from liquid suspension must be ideally isolated (de-agglomerated), without particle losses, homogeneously distributed in a high density of particles per substrate area for efficient analysis, with good statistics of the counted particles. Various sample preparation approaches to meet the latter requirements have been reported in the literature, e.g. electrospray, substrate surface treatment, embedding the particulate material and polishing the cross-section, or addition of ligands to the suspended nanostructures to enhance their hydrophilicity [1], [2], [3], [4].
In this study we have systematically tested the efficacy of a new deposition procedure for graphene-related 2D materials (GR2M’s) from liquid suspension onto a substrate for quantitative analysis of their size and shape distribution with electron microscopy. The technique is an extension of the conventional drop-casting method, and we have designated it “wire-print” deposition. It consists of two steps, first one being usual drop-casting on a copper substrate and second one involving a thin copper wire with a sub-mm diameter being dipped into the deposited droplet and retracted with a corresponding half-spherical droplet attached on its tip and final deposition of this entire nL-amount of suspension onto e.g. a silicon wafer for microscopical, detailed analysis. The result of 11 series of such a wire-print deposition for a graphene-based ink is shown in Figure 1 (labeled A-L), where various conditions (treatment of the starting suspension) have been experimented with a repetition of up to 10 times per condition, all together 86 spots on a silicon wafer of 10 mm x 10 mm.
The result of one series of 8 repeated wire-print depositions is shown in Figure 2, where the deposited spots are visualized with SEM. Note the weak presence of coffee-rings, irregular spot shape, and presence of agglomerates. The results for the measured flake size distribution expressed as ECD (equivalent circular diameter) are represented in Fig. 3 for all the eight depositions. Both the mean value of the 8 ECD distributions and the total number of flakes deposited in each spot show a variance in the range of 17% and 22%, respectively, see Table 1. In the context of accurate analysis of such challenging complex materials these numbers can be considered as excellent and demonstrate the high benefit of the wire-print deposition for accurate morphological measurements on GR2M’s.
T2 - Microscopy and Microanalysis 2025
CY - Salt Lake City, UTAH, USA
DA - 27.07.2025
KW - Sample preparation
KW - Graphene
KW - Electron Microscopy
KW - Morphology
PY - 2025
AN - OPUS4-64083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
T1 - Gold nanocubes with monodispersed size distribution (SEM SE)
N2 - Gold nanocubes with a monodispersed size distribution (edge = 55 nm) deposited on a silicon wafer. These tiny uniform cubes were produced as reference nanoparticles in the frame of the European project nPSize - Improved traceability chain of nanoparticle size measurements. SEM Image acquired at 10 kV with an in-lens secondary electron detector. Image colored in ImageJ using LUT “Orange hot.” Published in Microscopy and Microanalysis 25(S2) (2019) 2328.
KW - Nanoparticles
KW - Nanocubes
KW - Electron microscopy
KW - Reference materials
PY - 2020
DO - https://doi.org/10.1017/S1551929520001157
VL - 28
IS - 4
SP - 12
EP - 12
PB - Cambridge University Press
CY - Cambridge, UK
AN - OPUS4-51352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Kersting, R.
A1 - Hagenhoff, B.
A1 - Bennet, Francesca
A1 - Ciornii, Dmitri
A1 - Nymark, P.
A1 - Grafström, R.
A1 - Hodoroaba, Vasile-Dan
T1 - Reliable Surface Analysis Data of Nanomaterials in Support of Risk Assessment Based on Minimum Information Requirements
N2 - The minimum information requirements needed to guarantee high-quality surface Analysis data of nanomaterials are described with the aim to provide reliable and traceable Information about size, shape, elemental composition and surface chemistry for risk assessment approaches.
The widespread surface analysis methods electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were considered. The complete analysis sequence from sample preparation, over measurements, to data analysis and data format for reporting and archiving is outlined. All selected methods are used in surface analysis since many years so that many aspects of the analysis (including (meta)data formats) are already standardized. As a practical analysis use case, two coated TiO2 reference nanoparticulate samples, which are available on the Joint Research Centre (JRC) repository, were selected. The added value of the complementary analysis is highlighted based on the minimum information requirements, which are well-defined for the analysis methods selected. The present paper is supposed to serve primarily as a source of understanding of the high standardization level already available for the high-quality data in surface analysis of nanomaterials as reliable input for the nanosafety community.
KW - Electron microscopy
KW - X-ray photoelectron spectroscopy
KW - Secondary ion mass spectrometry
KW - Energy dispersive X-ray spectroscopy
KW - Standardization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522683
DO - https://doi.org/10.3390/nano11030639
VL - 11
IS - 3
SP - 639
PB - MDPI
AN - OPUS4-52268
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sattari, S.
A1 - Beyranvand, S.
A1 - Soleimani, K.
A1 - Rassoli, K.
A1 - Salahi, P.
A1 - Donskyi, Ievgen
A1 - Shams, A.
A1 - Unger, Wolfgang
A1 - Yari, A.
A1 - Farjanikish, G.
A1 - Nayebzadeh, H.
A1 - Adeli, M.
T1 - Boronic Acid-Functionalized Two-Dimensional MoS2 at Biointerfaces
N2 - While noncovalent interactions at two-dimensional nanobiointerfaces are extensively investigated, less knowledge about covalent interactions at this interface is available. In this work, boronic acid-functionalized 2D MoS2 was synthesized and its covalent multivalent interactions with bacteria and nematodes were investigated. Polymerization of glycidol by freshly exfoliated MoS2 and condensation of 2,5-thiophenediylbisboronic acid on the produced platform resulted in boronic acid-functionalized 2D MoS2. The destructive interactions between 2D MoS2 and bacteria as well as nematodes were significantly amplified by boronic acid functional groups. Because of the high antibacterial and antinematodal activities of boronic acid-functionalized 2D MoS2, its therapeutic efficacy for diabetic wound healing was investigated. The infected diabetic wounds were completely healed 10 days after treatment with boronic acid-functionalized 2D MoS2, and a normal structure for recovered tissues including different layers of skin, collagen, and blood vessels was detected.
KW - XPS
KW - Boronic acid-functionalized 2D MoS2
KW - Covalent interactions
KW - Bacteria
KW - Nanobiointerfaces
PY - 2020
DO - https://doi.org/10.1021/acs.langmuir.0c00776
VL - 36
IS - 24
SP - 6706
EP - 6715
PB - ACS American Chemical Society
AN - OPUS4-51024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Al-Waqfi, R. A.
A1 - Khan, C. J.
A1 - Irving, O. J.
A1 - Matthews, Lauren
A1 - Albrecht, T.
T1 - Crowding Effects during DNA Translocation in Nanopipettes
N2 - Quartz nanopipettes are an important emerging class of electric single-molecule sensors for DNA, proteins, their complexes, as well as other biomolecular targets. However, in comparison to other resistive pulse sensors, nanopipettes constitute a highly asymmetric environment and the transport of ions and biopolymers can become strongly directiondependent. For double-stranded DNA, this can include the characteristic translocation time and tertiary structure, but as we show here, nanoconfinement can also unlock capabilities for biophysical and bioanalytical studies at the single-molecule level. To this end, we show how the accumulation of DNA inside the nanochannel leads to crowding effects, and in some cases reversible blocking of DNA entry, and provide a detailed analysis based on a range of different DNA samples and experimental conditions. Moreover, using biotin-functionalized DNA and streptavidinmodified gold nanoparticles as target, we demonstrate in a proof-of-concept study how the crowding effect, and the resulting increased residence time in nanochannel, can be exploited by first injecting the DNA into the nanochannel, followed by incubation with the nanoparticle target and analysis of the complex by reverse translocation. We thereby integrate elements of sample processing and detection into the nanopipette, as an important conceptual advance, and make a case for the wider applicability of this device concept.
KW - DNA translocation
KW - Transport
KW - Resistive-pulse sensing
KW - Nanopores
KW - Nanopipettes
KW - Crowding
KW - Confinement
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630448
DO - https://doi.org/10.1021/acsnano.5c01529
SN - 1936-086X
VL - 19
IS - 17
SP - 1
EP - 9
PB - ACS Publications
AN - OPUS4-63044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pellegrino, F.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Unveiling Order in Graphene Oxide Synthesis Through A Design of Experiment and Chemometric Strategy Based on Tour’s Method
N2 - Graphene oxide (GO), a derivative of graphene containing oxygen functional groups, shows significant potential for a wide range of applications due to its unique electrical, mechanical, and chemical properties. Traditional synthesis methods, such as Tour's method, often rely on trial-and-error, leading to variations in product quality and yield. To address these challenges, we applied Design of Experiments (DoE) to systematically investigate the effects of key synthesis parameters, including reaction temperature, reaction time, and oxidant concentration. We identified the most significant factors influencing GO characteristics using a Plackett-Burman design and chemometric analysis. Our results highlight that the oxidation level is the most critical factor, impacting outcomes observed through various characterization techniques, such as UV-Vis spectroscopy and X-Ray Diffraction. Principal Component Analysis (PCA) and Multiple Linear Regression (MLR) provided insights into the synthetic parameters most strongly affecting material properties. While some findings aligned with expectations, others were counterintuitive. For instance, oxidation temperature had a minimal effect on the final material characteristics and may not need to be prioritized in the synthesis process. On the other hand, stirring was found to enhance the homogeneity of the material and promote more uniform oxidation. This study demonstrates the effectiveness of DoE in the controlled production of graphene oxide, offering a reliable framework for manufacturing high-quality GO tailored to specific applications. By minimizing time and resource consumption, this approach is increasingly relevant in the context of materials science, which demands higher quality, safety and sustainability standards.
T2 - Joint Regulatory Risk Assessors Summit – Advancing Safety & Sustainability Assessments of Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - Graphene oxide
KW - Chemometry
KW - UV-Vis
KW - XRD
KW - XPS
KW - EDX
PY - 2025
UR - https://macrame-project.eu/macrame-meetings-workshops/jointrras/#Agenda
AN - OPUS4-63676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Competence Center nano@BAM Welcomes ISO/TC 229 Meeting in Berlin
N2 - The Competence Center nano@BAM is presented. Examples directly related to the activities of the ISO Technical Committee TC 229 Nanotechnologies as well as BAM projects on nano reference measurement procedures, nano reference materials and nano reference data sets are showed.
T2 - The 32nd ISO/TC 229 IEC/TC 113 JWG2 General Meeting
CY - Berlin, Germany
DA - 06.11.2023
KW - ISO/TC 229 Nanotechnologies
KW - Nanoparticles
KW - Nano@BAM
KW - Reference materials
KW - Reference data
KW - Reference procedures
PY - 2023
AN - OPUS4-58814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Radnik, Jörg
A1 - Chemello, Giovanni
A1 - Knigge, Xenia
A1 - Al-Sabbgh, Dominik
A1 - Hodoroaba, Vasile-Dan
T1 - XPS, HAXPES, XRD and SEM datasets of functionalized graphene nanoplateletes
N2 - The datasets from (Hard Energy) X-ray photoelectron spectroscopy, X-ray diffraction and Scanning Electron Microsopy are related to the publication
G. Chemello, X. Knigge, D. Ciornii, B.P. Reed, A.J. Pollard, C.A. Clifford, T. Howe, N. Vyas, V.-D. Hodoroaba, J. Radnik
"Influence of the morphology on the functionalization of graphene nanoplatelets analyzed by comparative photoelectron spectroscopy with soft and hard X-rays"
Advanced Materials Interfaces (2023), DOI: 10.1002/admi.202300116.
KW - Graphene related 2D materials
KW - X-ray photoelectron spectroscopy
KW - Hard-energy X-ray photoelectron spectroscopy
KW - Scanning electron microscopy
KW - Powder X-ray diffraction
PY - 2023
DO - https://doi.org/10.5281/zenodo.7956497
PB - Zenodo
CY - Geneva
AN - OPUS4-57898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferrari, Bruno
A1 - Fantin, Andrea
A1 - Said, D.
A1 - Fitch, A. N.
A1 - Suárez Ocano, Patricia
A1 - Mishurova, Tatiana
A1 - Roveda, Ilaria
A1 - Kromm, Arne
A1 - Darvishi Kamachali, Reza
A1 - Bruno, Giovanni
A1 - Evans, Alexander
A1 - Requena, G.
A1 - Agudo Jácome, Leonardo
A1 - Serrano Munoz, Itziar
T1 - The impact of scanning strategy on cell structures in PBF-LB/M/IN718: an in situ synchrotron x-ray diffraction study
N2 - In additive manufacturing, any change of the process parameters, such as scanning strategy, directly affects the cooling rates, heat accumulation, and overall thermal history of the build. Consequently, parts built with different process parameters tend to have different levels of crystallographic texture, residual stress, and dislocation density. These features can influence the properties of the material and their development during post-processing operations. In this study, IN718 prisms were built by laser powder bed fusion (PBF-LB/M) using two different scanning strategies (continuous 67° rotations around the build direction, ROT, and alternating 0°/67° scans, ALT) to provide two different as-built conditions. In situ time-resolved synchrotron diffraction was performed during a solution heat treatment at 1027 °C for 1 h. Ex situ scanning electron microscopy was used to support and complement the in situ observations. An approach to quantify the effect of elemental microsegregation at the cell walls is developed based on the deconvolution of asymmetric γ-nickel matrix peaks. Following this approach, the scanning strategies are shown to affect the as-built fraction of cell walls in the material, resulting in a difference of approximately 5 %, in weight fraction, between ROT and ALT (19 % vs. 24 %, respectively). This microsegregation was observed to be rapidly homogenized during the heating ramp, and no significant changes to the peak shape in the γ peaks occurred during the isothermal part of the heat treatment, regardless of the scanning strategy.
KW - Additive manufacturing
KW - Inconel 718
KW - Synchrotron x-ray diffraction
KW - Heat treatment
KW - Laser powder bed fusion
KW - Cellular microstructure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650958
DO - https://doi.org/10.1016/j.jmrt.2025.11.214
SN - 2238-7854
VL - 41
SP - 593
EP - 608
PB - Elsevier B.V.
AN - OPUS4-65095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yu, C.-H.
T1 - Distribution of subsurface residual stress as a function of wall thickness in stainless steel 316L LPBF structures
N2 - The subsurface residual stress in laser powder bed fused 316L structures was analyzed using X-ray diffraction (XRD) and layer removal. The influence of varying structure thicknesses was investigated. In this study the importance of combining surface roughness measurements with XRD was shown. Moreover, a clear relation between the structure thickness and the subsurface residual stress profiles was observed.
T2 - The 11th International Conference on Residual Stress
CY - Nancy, Frankreich
DA - 28.03.2022
KW - AGIL
KW - Residual Stress
KW - X-ray Diffraction
KW - Additive Manufacturing
PY - 2022
AN - OPUS4-54581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liens, A.
A1 - Reveron, H.
A1 - Douillard, T.
A1 - Blanchard, N.
A1 - Lughi, V.
A1 - Sergo, V.
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
A1 - Schomer, S.
A1 - Fürderer, T.
A1 - Adolfsson, E.
A1 - Courtois, N.
A1 - Swain, M.
A1 - Chevalier, J.
T1 - Phase transformation induces plasticity with negligible damage in ceria-stabilized zirconia-based ceramics
N2 - Ceramics and their composites are in general brittle materials because they are predominantly made up of ionic and covalent bonds that avoid dislocation motion at room temperature. However, a remarkable ductile behavior has been observed on newly developed 11 mol.% ceria-stabilized zirconia (11Ce-TZP) composite containing fine alumina (8 vol.% Al2O3) and elongated strontium hexa-aluminate (8 vol.% SrAl12O19) grains. The as-synthesized composite also has shown full resistance to Low Temperature Degradation (LTD), relatively high strength and exceptionally high Weibull modulus, allowing its use in a broader range of biomedical applications. In this study, to deepen the understanding of plastic deformation in Ce-TZP based composites that could soon be used for manufacturing dental implants, different mechanical tests were applied on the material, followed by complete microstructural characterization. Distinct from pure Ce-TZP material or other zirconia-based ceramics developed in the past, the material here studied can be permanently strained without affecting the Young modulus, indicating that the ductile response of tested samples cannot be associated to damage occurrence. This ductility is related to the stress-induced tetragonal to monoclinic (t-m) zirconia phase transformation, analogue to Transformation-Induced Plasticity (TRIP) steels, where retained austenite is transformed to martensite. The aim of this study is to corroborate if the observed plasticity can be associated exclusively to the zirconia t-m phase transformation, or also to microcraking induced by the transformation. The t-m transformed-zones produced after bending and biaxial tests were examined by X-ray refraction and SEM/TEM coupled with Raman. The results revealed that the observed elastic-plastic behavior occurs without extensive microcracking, confirming a purely elastic-plastic behavior driven by the phase transformation (absence of damage).
KW - Zirconia
KW - Ceria
KW - Ceramic matrix composite
KW - Plasticity
KW - Phase transformation
KW - X-Ray Refraction
PY - 2020
UR - http://www.sciencedirect.com/science/article/pii/S1359645419307177
DO - https://doi.org/10.1016/j.actamat.2019.10.046
SN - 1359-6454
VL - 183
SP - 261
EP - 273
PB - Elsevier Ltd.
AN - OPUS4-49740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hajian, A.
A1 - Konegger, T.
A1 - Bielecki, K.
A1 - Mieller, Björn
A1 - Rabe, Torsten
A1 - Schwarz, S.
A1 - Zellner, C.
A1 - Schmid, U.
T1 - Wet chemical porosification with phosphate buffer solutions for permittivity reduction of LTCC substrates
N2 - The wireless high-frequency technology requires a robust, cost-effective, and highly integrated substrate technology offering the capability for areas of tailored permittivity. The wet-chemical porosification of low temperature co-fired ceramics (LTCC) substrates offers such an approach by locally embedding air. Porosification of LTCC in both extremely acidic and alkaline media has been investigated in previous works. However, for improving the available knowledge on the porosification of LTCC with H3PO4 as a standard and a widely used etching solution, the impact of solution concentration was systematically investigated and a substantial improvement in the etching performance was achieved. Moreover, in the present study, for the first time, the intermediate pH values, and the impact of pH as a key parameter on the etching process have been investigated. For this purpose, the applicability of phosphate buffer solution (PBS) as a prospective novel etchant mixture for the porosification of a commercially available LTCC tape (Ceramtape GC) was explored. Valuable information about surface morphology, crystalline composition, and the pore structure of the etched LTCCs was gathered employing scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, and mercury porosimetry measurements. Based on these findings, the performance of PBS-based etchant systems towards the generation of porous LTCCs combining high depths of porosification with acceptable surface characteristics for subsequent metallization is demonstrated. Based on the obtained results, by application of a 0.2 mol L−1 solution of PBS, the effective relative permittivity of test samples with a thickness of approximately 600 µm and a porosification depth of 186 µm from each side, could be reduced up to 10% of its initial “as fired” value. Also, based on the measurement results and by measuring the depth of porosification, the permittivity of the etched layer was estimated to show a reduction of up to 22% compared to the initial “as fired” value.
KW - LTCC
KW - Porosification
KW - Wet chemical etching
KW - Permittivity reduction
PY - 2020
DO - https://doi.org/10.1016/j.jallcom.2020.158059
SN - 0925-8388
VL - 863
SP - 158059
PB - Elsevier B.V.
AN - OPUS4-51800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mehta, B.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Markötter, Henning
A1 - Bruno, Giovanni
A1 - Hryha, E.
A1 - Nyborg, L.
A1 - Virtanen, E.
T1 - Microstructure, mechanical properties and fracture mechanisms in a 7017 aluminium alloy tailored for powder bed fusion – laser beam
N2 - This study addressed a 7017 Al-alloy tailored for powder bed fusion – laser beam (PBF-LB) process. The alloy was prepared by mixing 3 wt% Zr and 0.5 wt% TiC powder to standard pre-alloyed 7017 grade aluminium powder. This made printing of the alloys possible avoiding solidification cracking in the bulk and achieving high relative density (99.8 %). Such advanced alloys have significantly higher Young’s modulus (>80 GPa) than conventional Al-alloys (70–75 GPa), thus making them attractive for applications requiring high stiffness. The resulting microstructure in as-printed condition was rich in particles originating from admixed powders and primary precipitates/inclusions originating from the PBF-LB process. After performing a T6-like heat treatment designed for the PBF-LB process, the microstructure changed: Zr-nanoparticles and Fe- or Mg/Zn- containing precipitates formed thus providing 75 % increase in yield strength (from 254 MPa to 444 MPa) at the cost of decreasing ductility (∼20 % to ∼9 %). In-situ tensile testing combined with SXCT, and ex-situ tensile testing combined with fracture analysis confirmed that the fracture initiation in both conditions is highly dependent on defects originated during printing. However, cracks are deflected from decohesion around Zr-containing inclusions/precipitates embedded in the Al-matrix. This deflection is seen to improve the ductility of the material.
KW - Additive manufacturing
KW - Powder bed fusion Laser beam
KW - X-ray computed tomography
KW - Strengthening mechanisms
KW - Crack propagation
KW - Zirconium
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568243
DO - https://doi.org/10.1016/j.matdes.2023.111602
SN - 0264-1275
VL - 226
SP - 1
EP - 14
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-56824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Manufacturing a safer world: Diffraction based residual stress analysis for metal additive manufacturing
N2 - Metal Additive Manufacturing (AM) technologies such as Laser Powder Bed Fusion (LPBF) are characterized by layer wise construction, which enable advancements of component design, with associated potential gains in performance and efficiency. However, high magnitude residual stresses (RS) are often a product of the rapid thermal cycles typical of the layerwise process. Therefore, a deep understanding of the formation of RS, the influence of process parameters on their magnitude and the impact on mechanical performance is crucial for widespread application. The experimental characterisation of these RS is essential for safety related engineering application and supports the development of reliable numerical models. Diffraction-based methods for RS analysis using neutrons and high energy X-rays enable non-destructive spatially resolved characterisation of both surface and bulk residual stresses in complex components. This presentation will provide an overview of recent research by the BAM at large scale facilities for the characterization of residual stresses in LPBF metallic alloys as a function of process parameters. In addition, the challenges posed by the textured and hierarchical microstructures of LPBF materials on diffraction-based RS analysis in AM materials will be discussed. This will include the question of the d0 reference lattice spacing and the appropriate choice of the diffraction elastic constants (DECs) to calculate the level of RS in LPBF manufactured alloys.
T2 - 11th INternational Conference on Residual Stress (ICRS11)
CY - Online meeting
DA - 28.03.2021
KW - Residual stress analysis
KW - Neutron diffraction
KW - X-ray diffraction
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - AGIL
PY - 2022
AN - OPUS4-54676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Procedures for quantitative characterization of periodic minimal surface structures (TMPSS)
N2 - Additively manufactured (AM) triply periodic metallic minimum surface structures (TPMSS, from the English Triply Periodic Minimum Surface Structures) fulfill several requirements in both biomedical and engineering fields: tunable mechanical properties, low sensitivity to manufacturing defects, mechanical stability, and high energy absorption. However, they also present some quality control challenges that may prevent their successful application. In fact, optimization of the AM process is impossible without considering structural features such as manufacturing accuracy, internal defects, and surface topography and roughness. In this study, quantitative nondestructive analysis of Ti-6Al-4V alloy TPMSS was performed using X-ray computed tomography (XCT). Several new image analysis workflows are presented to evaluate the effects of buildup direction on wall thickness distribution, wall degradation, and surface roughness reduction due to chemical etching of TPMSS. It is shown that the fabrication accuracy is different for the structural elements printed parallel and orthogonal to the fabricated layers. Different strategies for chemical etching showed different powder removal capabilities and thus a gradient in wall thickness. This affected the mechanical performance under compression by reducing the yield stress. A positive effect of chemical etching is the reduction of surface roughness, which can potentially improve the fatigue properties of the components. Finally, XCT was used to correlate the amount of powder retained with the pore size of the TPMSS, which can further improve the manufacturing process.
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Surface roughness
KW - Additive manufacturing
KW - Computed tomography
KW - Wall thickness
KW - Machine learning
KW - Manufacturing defects
PY - 2022
AN - OPUS4-56162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Synchrotron x ray refraction detects microstructure and porosity evolution during in situ heat treatments in an LPBF ALSI10MG alloy
N2 - The complexity of any microstructural characterization significantly increases when there is a need to evaluate the icrostructural evolution as a function of temperature. To date, this characterization is primarily performed by undertaking elaborative ex-situ experiments where the material’s heating procedure is interrupted at different temperatures or times. Moreover, these studies are often limited to a region smaller than the representative elementary volume, which can lead to partial or even biased interpretations of the collected data. This limitation can be greatly overcome by using in-situ synchrotron X-ray refraction (SXRR).
T2 - ICTMS 2022
CY - Grenoble, France
DA - 27.06.2022
KW - Synchrotron refraction
KW - In situ heating
KW - AlSi10Mg alloy
KW - Additive manufacturing
KW - Microstructural evolution
PY - 2022
AN - OPUS4-55199
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Surmeneva, M.
A1 - Koptyug, A.
A1 - Khrapov, D.
A1 - Ivanov, Yuriy
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Prymak, O.
A1 - Loza, K.
A1 - Epple, M.
A1 - Bruno, Giovanni
A1 - Surmenev, R.
T1 - In situ synthesis of a binary Ti–10at% Nb alloy by electron beam melting using a mixture of elemental niobium and titanium powders
N2 - This study reports the results of the preliminary assessment to fabricate Ti-10at% Nb alloy by electron beam melting (EBM®) from a blend of elemental Nb and Ti powders. The microstructure of the EBM-manufactured Ti-10at% Nb alloys is sensitive to the following factors: different sintering properties of Nb and Ti powders, powder particle properties, material viscosities at varying melt pool temperatures, β-stabilizer element content and the EBM® process parameters. Three phases were observed in as-manufactured Ti-10at% Nb alloy: μm-size Nb phase, a Nb-rich β-solid solution surrounding Nb phase, lamellar structured α-phase and β-solid solution with different distribution and volume fraction. Thus, the combination of powder particle characteristics, very short time material spends in molten condition and sluggish kinetics of mixing and diffusional process in Ti-Nb alloy results in heterogeneous microstructures depending on the local Nb content in the powder blend and the EBM® process conditions.
KW - Additive manufacturing
KW - Electron beam melting
KW - Ti-Nb alloy
KW - In situ alloying
PY - 2020
DO - https://doi.org/10.1016/j.jmatprotec.2020.116646
VL - 282
SP - 116646
PB - Elsevier B.V.
AN - OPUS4-50457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Léonard, Fabien
A1 - Zhang, Zhen
A1 - Krebs, Holger
A1 - Bruno, Giovanni
T1 - Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-ray Computed Tomography
N2 - The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.
KW - ANFO
KW - Explosives
KW - Surface area
KW - Porosity
KW - XCT
KW - Data processing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505395
DO - https://doi.org/10.3390/ma13051230
VL - 13
IS - 5 (Special Issue "Micro Non-Destructive Testing and Evaluation")
SP - 1230
PB - MDPI
AN - OPUS4-50539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Oster, Simon
A1 - Maierhofer, Christiane
A1 - Bruno, Giovanni
ED - Czujko, T.
ED - Benedetti, M.
T1 - Can Potential Defects in LPBF Be Healed from the Laser Exposure of Subsequent Layers? A Quantitative Study
N2 - Additive manufacturing (AM) of metals and in particular laser powder bed fusion (LPBF) enables a degree of freedom in design unparalleled by conventional subtractive methods. To ensure that the designed precision is matched by the produced LPBF parts, a full understanding of the interaction between the laser and the feedstock powder is needed. It has been shown that the laser also melts subjacent layers of material underneath. This effect plays a key role when designing small cavities or overhanging structures, because, in these cases, the material underneath is feed-stock powder. In this study, we quantify the extension of the melt pool during laser illumination of powder layers and the defect spatial distribution in a cylindrical specimen. During the LPBF process, several layers were intentionally not exposed to the laser beam at various locations, while the build process was monitored by thermography and optical tomography. The cylinder was finally scanned by X-ray computed tomography (XCT). To correlate the positions of the unmolten layers in the part, a staircase was manufactured around the cylinder for easier registration. The results show that healing among layers occurs if a scan strategy is applied, where the orientation of the hatches is changed for each subsequent layer. They also show that small pores and surface roughness of solidified material below a thick layer of unmolten material (>200 µm) serve as seeding points for larger voids. The orientation of the first two layers fully exposed after a thick layer of unmolten powder shapes the orientation of these voids, created by a lack of fusion.
KW - Computed tomography
KW - Laser Powder Bed Fusion
KW - In situ monitoring
KW - infrared Thermography
KW - Optical Tomography
KW - Additive manufacturing
KW - AISI 316L
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528778
DO - https://doi.org/10.3390/met11071012
VL - 11
IS - 7
SP - 1012
PB - MDPI
CY - Basel
AN - OPUS4-52877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Kasperovich, G.
A1 - Requena, G.
A1 - Haubrich, J.
A1 - Bruno, Giovanni
T1 - Classification of defect types in SLM Ti-6Al-V4 by X-ray refraction topography
N2 - Porosity in additively manufactured materials, such as laser powder bed fusion Ti-Al6-V4, can play an important role in their mechanical performance. Not only the total porosity but also the shape/morphology of the individual pores need to be considered. Therefore, it is necessary to determine the distributions of different defect types (especially fusing defects and keyhole pores) and their dependence on process parameters. We show that synchrotron X-ray refraction radiography allows analysis of large samples (up to several millimeters) without compromising the detectability of submicrometer defects. Correspondingly, a classification tool is introduced that is able to quantitatively distinguish defects such as keyhole pores and binding defects with a confidence level of 94 %, even when the shape cannot be discerned because of limited spatial resolution.
KW - Additive manufacturing
KW - Selective laser melting
KW - X-ray refraction
KW - Microscopy
KW - Porosity
KW - X-ray computed tomography
KW - BAMline
KW - Synchrotron Radiation
PY - 2020
DO - https://doi.org/10.1520/MPC20190080
SN - 2379-1365
VL - 9
IS - 1
SP - 82
EP - 93
PB - ASTM International
CY - West Conshohocken, PA
AN - OPUS4-50470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - To see and not to see - Möglichkeiten und Grenzen der Schadensanalyse mit CT an Kompositmaterialien
N2 - Anhand von drei Beispielen (Datenfusion an CFK; Machine Learning an Metall-Matrix-Kompositen sowie Refraktion an CFK) wird gezeigt, wie die BAM mit neuen Analysemethoden mehr Informationen aus CT-Datensätzen extrahieren kann, sowie mit der Refraktion eine Analysemethode besitzt, die in Fällen eingesetzt werden kann, bei denen klassische Durchstrahlungsmethoden kein Ergebnis liefern.
T2 - InnoTesting 2020
CY - Wildau, Germany
DA - 27.02.2020
KW - Computed tomography
KW - Computertomographie
KW - Röntgenrefraktion
KW - Machine Learning
KW - Datenfusion
KW - Data Fusion
KW - Synchrotron
PY - 2020
AN - OPUS4-50485
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Fernández, R.
A1 - Saliwan Neumann, Romeo
A1 - González-Doncel, G.
A1 - Bruno, Giovanni
T1 - Dislocation substructures in pure aluminium after creep deformation as studied by electron backscatter diffraction
N2 - In the present work, electron backscatter diffraction was used to determine the microscopic dislocation structures generated during creep (with tests interrupted at the steady state) in pure 99.8% aluminium. This material was investigated at two different stress levels, corresponding to the power-law and power-law breakdown regimes. The results show that the formation of subgrain cellular structures occurs independently of the crystallographic orientation. However, the density of these cellular structures strongly depends on the grain crystallographic orientation with respect to the tensile axis direction, with <111> grains exhibiting the highest densities at both stress levels. It is proposed that this behaviour is due to the influence of intergranular stresses, which is different in <111> and <001> grains.
KW - Creep
KW - Pure aluminium
KW - Electron backscatter diffraction
KW - Cellular structures
KW - Power law and power-law breakdown
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552003
DO - https://doi.org/10.1107/S1600576722005209
SN - 0021-8898
SN - 1600-5767
VL - 55
SP - 860
EP - 869
PB - Wiley-Blackwell
CY - Copenhagen
AN - OPUS4-55200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Mack, D. E.
A1 - Laquai, René
A1 - Kupsch, Andreas
A1 - Helle, O.
A1 - Sebold, D.
A1 - Vaßen, R.
A1 - Bruno, Giovanni
T1 - Charakterisierung der Porositäts- und Rissdichteentwicklung in Wärmedämmschichten von Gasturbinenschaufeln mittels Synchrotron Refraktions Radiographie
N2 - Die Degradation von Wärmedämmschichten(thermal barrier coatings - TBCs) in Gasturbinen durch glasartige Calcium-Magnesium-Aluminiumsilikat (CMAS)Ablagerungen aus verschiedenen Quellen istseit vielen Jahren ein anhaltendes Problem. In dieser Studie wurde mit Hilfe derSynchrotron-Röntgen-Refraktions-Radiographie (SXRR), und vergleichend mit der Elektronenmikroskopie, das Eindringen von CMAS in die poröse Struktur von atmosphärisch plasmagespritzten (APS)TBCs sowie die Bildung und das Wachstum von Rissen unter thermisch zyklischer Belastung untersucht. Die Ergebnisse deuten darauf hin, dass die Infiltration sowie deren Kinetik im Brenner-Teststand wesentlich vom Benetzungsverhalten des CMAS beeinflusst werden. Trotz desoffensichtlichen Angriffs von CMAS auf die Korngrenzen hat die Wechselwirkung von Yttriumdioxid-stabilisiertem Zirkoniumdioxid (YSZ) mit intrudiertem CMAS keinen unmittelbaren Einfluss auf die Struktur und Dichte der innen Oberflächen(Risse, Poren). In einem späteren Stadium wird die Bildung von Rissen senkrecht zur äußeren Oberfläche in einer breiteren Zone der TBC-Schicht beobachtet.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - CMAS - Calcium-Magnesium-Aluminiumsilikat
KW - SXRR - Synchrotron X-ray Refraction Radiography
KW - TBC - Thermal barrier coatings
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526732
UR - https://jahrestagung.dgzfp.de/Programm#P32
SP - 1
EP - 15
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-52673
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evans, Alexander
A1 - Schröder, Jakob
A1 - Pirling, T.
A1 - Ulbricht, Alexander
A1 - Suárez Ocaño, Patricia
A1 - Bruno, Giovanni
T1 - Resolving the Subsurface Residual Stress Maximum in Laser Powder Bed-Fused 316L Stainless Steel by Diffraction-Based Analysis
N2 - Laser powder bed fusion (PBF-LB/M) is a metal additive manufacturing process. Due to the complex nature of the layer-wise, repeated heating and cooling cycles, it tends to generate high-magnitude residual stresses. If not correctly understood and mitigated through in- or post-process approaches, these residual stresses can be detrimental as they are often tensile at the surface. However, determining the magnitude and location of peak tensile residual stresses is not trivial as they are often located subsurface. This work focuses on determining the magnitude and location of these deleterious tensile residual stresses in a PBF-LB/316L specimen. Two diffraction-based Methods are used to reveal the relationship between the residual stresses and the underlying microstructure. On the one hand, high spatial resolution Neutron diffraction is used to determine triaxial stresses from the bulk to a depth of 0.15 mm. On the other hand, laboratory X-ray diffraction coupled with electrolytical layer removal allows the biaxial residual stress depth profile to be probed from the surface to a depth of about 0.6 mm. The results show a good agreement between the two methods. The peak residual stress is shown to be 500 MPa, which appears as a plateau between 0.08 and 0.35 mm in depth.
KW - Residual stress
KW - Diffraction
KW - Laser Powder Bed Fusion
KW - 316L
KW - Additive manufacturing
KW - Microstructure
KW - AGIL
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652138
DO - https://doi.org/10.1007/s11837-025-07719-y
SN - 1543-1851
VL - 77
IS - 12
SP - 9726
EP - 9737
PB - Springer Nature
AN - OPUS4-65213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Making materials (digital) - Keramik
N2 - Der Vortrag gibt einen Überblick über die Materialklasse Keramik, insbesondere Technische Keramik. Nach einem kurzen Überblick über typische Anwendungen und Werkstoffe wird die keramische Prozesskette erläutert. Am Beispiel von Festigkeit wird der für Keramik typische, enge Zusammenhang zwischen Technologie, Mikrostruktur und Eigenschaften herausgearbeitet. Daraus werden Anforderungen für eine erfolgreiche Digitalisierung abgeleitet.
T2 - Workshop "STREAM" - Semantische Repräsentation, Vernetzung und Kuratierung von qualitätsgesicherten Materialdaten
CY - Darmstadt, Germany
DA - 26.09.2022
KW - Keramik
KW - Festigkeit
KW - Überblick
PY - 2022
AN - OPUS4-55859
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Synchrotron X-Ray Refraction detects microstructure and porosity evolution during in-situ heat treatments
N2 - The complexity of any microstructural characterization significantly increases when there is a need to evaluate the microstructural evolution as a function of temperature. To date, this characterization is primarily performed by undertaking elaborative ex-situ experiments where the material’s heating procedure is interrupted at different temperatures or times. Moreover, these studies are often limited to a region smaller than the representative elementary volume, which can lead to partial or even biased interpretations of the collected data. This limitation can be greatly overcome by using in-situ synchrotron X-ray refraction (SXRR). In this study, SXRR has been combined with in-situ heat treatment to monitor the porosity evolution as a function of temperature. It is shown that SXRR is a robust and straightforward method for time-resolved (3-5 min required per scan) evaluation of thermally induced microstructural changes over macroscopically relevant volumes.
T2 - SNI2022, German conference for research with synchrotron radiation, neutrons and ion beams at large facilities
CY - Berlin, Germany
DA - 05.09.2022
KW - Synchrotron X-Ray Refraction
KW - In situ heating
KW - AlSi10Mg
KW - Laser powder bed fusion
KW - Thermally induced porosity
PY - 2022
AN - OPUS4-55778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evsevleev, Sergei
A1 - Cabeza, S.
A1 - Mishurova, Tatiana
A1 - Garcés, G.
A1 - Sevostianov, I.
A1 - Requena, G.
A1 - Boin, M.
A1 - Hofmann, M.
A1 - Bruno, Giovanni
T1 - Stress-induced damage evolution in cast AlSi12CuMgNi alloy with one and two ceramic reinforcements. Part II: Effect of reinforcement orientation
N2 - While there is a large body of literature on the micro-mechanical behavior of metal matrix composites (MMCs) under uniaxial applied stress, very little is available on multi-phase MMCs. In order to cast light on the reinforcement mechanisms and damage processes in such multi-phase composites, materials made by an Al-based piston alloy and containing one and two ceramic reinforcements (planar-random oriented alumina fibers and SiC particles) were studied. In-situ compression tests during neutron diffraction experiments were used to track the load transfer among phases, while X-ray computed tomography on pre-strained samples was used to monitor and quantify damage. We found that damage progresses differently in composites with different orientations of the fiber mat. Because of the presence of intermetallic network, it was observed that the second ceramic reinforcement changed the load transfer scenario only at very high applied load, when also intermetallic particles break. We rationalized the present results combining them with previous investigations and using a micromechanical model.
KW - Multi-phase
KW - Metal matrix composites
KW - Intermetallics
KW - Computed tomography
KW - In-situ neutron diffraction
KW - Piston alloy
KW - Load transfer
PY - 2020
DO - https://doi.org/10.1007/s10853-019-04069-4
SN - 1573-4803
VL - 55
IS - 3
SP - 1049
EP - 1068
PB - Springer
AN - OPUS4-49460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernández, R.
A1 - Bokuchava, G.
A1 - Toda-Caraballo, I.
A1 - Bruno, Giovanni
A1 - Turchenko, V.
A1 - Gorshkova, Y.
A1 - González-Doncel, G.
T1 - Analysis of the Combined Strengthening Effect of Solute Atoms and Precipitates on Creep of Aluminum Alloys
N2 - The creep strengthening mechanisms in (age-hardenable) aluminum alloys are analyzed on the basis of a new microstructural study of powder samples, an analysis of a comprehensive revision of creep data from the literature, and a new modeling approach. A strategy based on the strength difference (SD) method to separate the contributions of solid solution atoms and precipitates to creep strengthening is proposed. The new methodology considers the combination of the two contributions avoiding the need of a threshold stress term in the creep equation. The contribution of both precipitates and solid solution is taken into account by means of the analysis of the lattice parameter variation with aging time. For this study, powders of two commercial AA2xxx alloys have been analyzed using diffraction methods. The experimental results are modeled using Lubarda's approach combined with the SD method.
KW - Aluminium
KW - Creep
KW - Diffraction
KW - Precipitation
KW - Solute atoms
PY - 2020
DO - https://doi.org/10.1002/adem.201901355
SN - 1438-1656
VL - 22
SP - 1901355
EP - 4
PB - Wiley-VCH Verlag
AN - OPUS4-50424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
A1 - Fernández, R.
A1 - González-Doncel, G.
A1 - Garcés, G.
T1 - Towards a comprehensive understanding of creep: Microstructural dependence of the pre-exponential term in Al
N2 - We show that the equation proposed by Takeuchi and Argon to explain the creep behavior of Al–Mg solid solution can be used to describe also the creep behavior of pure aluminum. In this frame, it is possible to avoid the use of the classic pre-exponential fitting parameter in the power law equation to predict the minimum creep strain rate. The effect of the fractal arrangement of dislocations, developed at the mesoscale, must be considered to fully explain the experimental data. These ideas allow improving the recently introduced SSTC model, fully describing the primary and secondary creep regimes of aluminum alloys without the need for fitting. Creep data from commercially pure Al99.8% and Al–Mg alloys tested at different temperatures and stresses are used to validate the proposed ideas.
KW - Creep
KW - Aluminum alloys
KW - Dislocations
KW - Fractal
KW - Stress exponent
KW - Neutron diffraction
PY - 2020
DO - https://doi.org/10.1016/j.msea.2020.139036
VL - 776
SP - 139036
AN - OPUS4-50437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Léonard, Fabien
A1 - Zhang, Zhen
A1 - Krebs, Holger
A1 - Bruno, Giovanni
T1 - Morphological characterisation of explosive powders by XCT: When grain numbers count
N2 - Ammonium nitrate (AN) prills are commonly used as an ingredient in industrial explosives and in fertilisers. Conventional techniques (such as BET or mercury intrusion porosimetry) can measure the open porosity and specific surface area of AN prill, but the closed porosity is not obtainable. This work was focused on evaluating X-ray computed tomography (XCT) as a non-destructive technique for the assessment of porosity in AN prills. An advanced data processing workflow was developed so that the segmentation and quantification of the CT data could be performed on the entire 3D volume, yet allowing the measurements (e.g.; volume, area, shape factor…) to be extracted for each individual phase (prill, open porosity, closed porosity) of each individual prill, in order to obtain statistically relevant data. Clear morphological and structural differences were seen and quantified between fertiliser and explosive products. Overall, CT can provide a very wide range of parameters that are not accessible to other techniques, destructive or non-destructive, and thus offers new insights and complementary information.
T2 - 10th Conference on Industrial Computed Tomography (iCT 2020)
CY - Wels, Austria
DA - 04.02.2020
KW - Ammonium nitrate
KW - Prill
KW - Non-destructive characterisation
KW - Porosity
KW - Specific surface area
PY - 2020
UR - http://www.ndt.net/?id=25118
SN - 1435-4934
VL - 25
IS - 2
SP - 1
EP - 6
PB - NDT.net
CY - Kirchwald
AN - OPUS4-50348
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Léonard, Fabien
T1 - Morphological characterisation of explosive powders by XCT: When grain numbers count
N2 - Ammonium nitrate (AN) prills are commonly used as an ingredient in industrial explosives and in fertilisers. Conventional techniques (such as BET or mercury intrusion porosimetry) can measure the open porosity and specific surface area of AN prill, but the closed porosity is not obtainable. This work was focused on evaluating X-ray computed tomography (XCT) as a non-destructive technique for the assessment of porosity in AN prills. An advanced data processing workflow was developed so that the segmentation and quantification of the CT data could be performed on the entire 3D volume, yet allowing the measurements (e.g.; volume, area, shape factor…) to be extracted for each individual phase (prill, open porosity, closed porosity) of each individual prill, in order to obtain statistically relevant data. Clear morphological and structural differences were seen and quantified between fertiliser and explosive products. Overall, CT can provide a very wide range of parameters that are not accessible to other techniques, destructive or non-destructive, and thus offers new insights and complementary information.
T2 - iCT2020
CY - Wels, Austria
DA - 04.02.2020
KW - Ammonium nitrate
KW - Prill
KW - Non-destructive characterisation
KW - Porosity
KW - Specific surface area
PY - 2020
AN - OPUS4-50347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Evans, Alexander
A1 - Polatidis, E.
A1 - Čapek, J.
A1 - Mohr, Gunther
A1 - Serrano-Munoz, Itziar
A1 - Bruno, Giovanni
T1 - Understanding the impact of texture on the micromechanical anisotropy of laser powder bed fused Inconel 718
N2 - The manufacturability of metallic alloys using laser-based additive manufacturing methods such as laser powder bed fusion has substantially improved within the last decade. However, local melting and solidification cause hierarchically structured and crystallographically textured microstructures possessing large residual stress. Such microstructures are not only the origin of mechanical anisotropy but also pose metrological challenges for the diffraction-based residual stress determination. Here we demonstrate the influence of the build orientation and the texture on the microstructure and consequently the mechanical anisotropy of as-built Inconel 718. For this purpose, we manufactured specimens with [001]/[011]-, [001]- and [011]/[111]-type textures along their loading direction. In addition to changes in the Young’s moduli, the differences in the crystallographic textures result in variations of the yield and ultimate tensile strengths. With this in mind, we studied the anisotropy on the micromechanical scale by subjecting the specimens to tensile loads along the different texture directions during in situ neutron diffraction experiments. In this context, the response of multiple lattice planes up to a tensile strain of 10% displayed differences in the load partitioning and the residual strain accumulation for the specimen with [011]/[111]-type texture. However, the relative behavior of the specimens possessing an [001]/[011]- and [001]-type texture remained qualitatively similar. The consequences on the metrology of residual stress determination methods are discussed.
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Electron backscatter diffraction
KW - Tensile testing
KW - Diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555840
DO - https://doi.org/10.1007/s10853-022-07499-9
SN - 1573-4803
VL - 2022
IS - 57
SP - 15036
EP - 15058
PB - Springer Science + Business Media B.V.
CY - Dordrecht
AN - OPUS4-55584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Evans, Alexander
A1 - Luzin, V.
A1 - Abreu Faria, G.
A1 - Degener, Sebastian
A1 - Polatidis, E.
A1 - Čapek, J.
A1 - Kromm, Arne
A1 - Dovzhenko, G.
A1 - Bruno, Giovanni
T1 - Texture-based residual stress analysis of laser powder bed fused Inconel 718 parts
N2 - Although layer-based additive manufacturing methods such as laser powder bed fusion (PBF-LB) offer an immense geometrical freedom in design, they are typically subject to a build-up of internal stress (i.e. thermal stress) during manufacturing. As a consequence, significant residual stress (RS) is retained in the final part as a footprint of these internal stresses. Furthermore, localized melting and solidification inherently induce columnar-type grain growth accompanied by crystallographic texture. Although diffraction-based methods are commonly used to determine the RS distribution in PBF-LB parts, such features pose metrological challenges in their application. In theory, preferred grain orientation invalidates the hypothesis of isotropic material behavior underlying the common methods to determine RS. In this work, more refined methods are employed to determine RS in PBF-LB/M/IN718 prisms, based on crystallographic texture data. In fact, the employment of direction-dependent elastic constants (i.e. stress factors) for the calculation of RS results in insignificant differences from conventional approaches based on the hypothesis of isotropic mechanical properties. It can be concluded that this result is directly linked to the fact that the {311} lattice planes typically used for RS analysis in nickel-based alloys have high multiplicity and less strong texture intensities compared with other lattice planes. It is also found that the length of the laser scan vectors determines the surface RS distribution in prisms prior to their removal from the baseplate. On removal from the baseplate the surface RS considerably relaxes and/or redistributes; a combination of the geometry and the scanning strategy dictates the sub-surface RS distribution.
KW - Additive manufacturing
KW - Electron backscattered diffraction
KW - Principal stress
KW - Residual stress
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578331
DO - https://doi.org/10.1107/S1600576723004855
SN - 1600-5767
VL - 56
IS - Pt 4
SP - 1076
EP - 1090
AN - OPUS4-57833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Fritsch, Tobias
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Bruno, Giovanni
A1 - Maierhofer, Christiane
A1 - Altenburg, Simon
T1 - On the Registration of Thermographic In Situ Monitoring Data and Computed Tomography Reference Data in the Scope of Defect Prediction in Laser Powder Bed Fusion
N2 - The detection of internal irregularities is crucial for quality assessment in metal-based additive manufacturing (AM) technologies such as laser powder bed fusion (L-PBF). The utilization of in-process thermography as an in situ monitoring tool in combination with post-process X-ray micro computed tomography (XCT) as a reference technique has shown great potential for this aim. Due to the small irregularity dimensions, a precise registration of the datasets is necessary as a
requirement for correlation. In this study, the registration of thermography and XCT reference datasets of a cylindric specimen containing keyhole pores is carried out for the development of a porosity prediction model. The considered datasets show variations in shape, data type and dimensionality, especially due to shrinkage and material elevation effects present in the manufactured part. Since the resulting deformations are challenging for registration, a novel preprocessing methodology is introduced that involves an adaptive volume adjustment algorithm which is based on the porosity distribution in the specimen. Thus, the implementation of a simple three-dimensional image-to-image registration is enabled. The results demonstrate the influence of the part deformation on the resulting porosity location and the importance of registration in terms of irregularity prediction.
KW - Selective laser melting (SLM)
KW - Laser powder bed fusion (L-PBF)
KW - Additive manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
KW - X-ray computed tomography (XCT)
KW - Defect detection
KW - Image registration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549412
DO - https://doi.org/10.3390/met12060947
VL - 12
IS - 6
SP - 1
EP - 21
PB - MDPI
AN - OPUS4-54941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sprengel, Maximilian
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Evans, Alexander
A1 - Serrano-Munoz, Itziar
A1 - Kromm, Arne
A1 - Pirling, T.
A1 - Bruno, Giovanni
A1 - Kannengießer, Thomas
T1 - Triaxial Residual Stress in Laser Powder Bed Fused 316L: Effects of Interlayer Time and Scanning Velocity
N2 - The triaxial distribution of the residual stress in laser powder bed fused austenitic steel 316L was determined by X-ray and neutron diffraction. The residual stress analysis results were linked to the thermal history of the specimens, which were manufactured with varying inter-layer-times and scanning velocities. A clear link between the in-process temperature of the specimens and the residual stress was found, based on in-situ monitoring data.
KW - Stainless Steel
KW - AGIL
KW - Residual Stress
KW - X-ray and Neutron Diffraction
KW - Additive Manufacturing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542620
DO - https://doi.org/10.1002/adem.202101330
SP - 1
EP - 13
PB - Wiley-VCH GmbH
AN - OPUS4-54262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - Surface and bulk residual stress in laser powder bed fused 316L: Influence of inter layer time and scanning velocity
N2 - The influence of the inter-layer-time and the scanning velocity on the surface and bulk residual stress in laser powder bed fused 316L specimens was investigated. This study combines X-ray and neutron diffraction results with the thermal history of the specimens acquired through in-situ process monitoring. The process parameter variations were observed to directly influence the thermal history, which gave new insights in the assessment of the residual stress results.
T2 - The 11th International Conference on Residual Stress
CY - Nancy, Frankreich
DA - 28.03.2022
KW - AGIL
KW - Residual Stress
KW - X-ray and Neutron Diffraction
KW - Additive Manufacturing
KW - Stainless Steel
PY - 2022
AN - OPUS4-54582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Texture Dependent Micromechanical Anisotropy of Laser Powder Bed Fused Inconel 718
N2 - Additive manufacturing methods such as laser powder bed fusion (LPBF) allow geometrically complex parts to be manufactured within a single step. However, as an aftereffect of the localized heat input, the rapid cooling rates are the origin of the large residual stress (RS) retained in as-manufactured parts. With a view on the microstructure, the rapid directional cooling leads to a cellular solidification mode which is accompanied by columnar grown grains possessing crystallographic texture. The solidification conditions can be controlled by the processing parameters and the scanning strategy. Thus, the process allows one to tailor the microstructure and the texture to the specific needs. Yet, such microstructures are not only the origin of the mechanical anisotropy but also pose metrological challenges for the diffraction-based RS determination. In that context the micromechanical elastic anisotropy plays an important role: it translates the measured microscopic strain to macroscopic stress. Therefore, it is of uttermost importance to understand the influence of the hierarchical microstructures and the texture on the elastic anisotropy of LPBF manufactured materials.
This study reveals the influence of the build orientation and the texture on the micro-mechanical anisotropy of as-built Inconel 718. Through variations of the build orientation and the scanning strategy, we manufactured specimens possessing [001]/[011]-, [001]-, and [011]/[111]-type textures. The resulting microstructures lead to differences in the macroscopic mechanical properties. Even further, tensile in-situ loading experiments during neutron diffraction measurements along the different texture components revealed differences in the microstrain response of multiple crystal lattice planes. In particular, the load partitioning and the residual strain accumulation among the [011]/[111] textured specimen displayed distinct differences measured up to a macroscopic strain of 10 %. However, the behavior of the specimens possessing [001]/[011]-and [001]-type texture was only minorly affected. The consequences on the metrology of RS analysis by diffraction-based methods are discussed.
T2 - International Conference on Additive Manufacturing ICAM 2022
CY - Orlando, FL, USA
DA - 31.10.2022
KW - Laser powder bed fusion
KW - Neutron diffraction
KW - Electron backscatter diffraction
KW - Mechanical behavior
PY - 2022
AN - OPUS4-56376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Fundamentals of diffraction-based residual stress and texture analysis of PBF-LB Inconel 718
N2 - Laser powder bed fusion (PBF-LB/M) of metallic alloys is a layer wise additive manufacturing process which provides significant scope for more efficient designs of components, benefiting performance and weight, leading to efficiency improvements for various sectors of industry. However, to benefit from these design freedoms, knowledge of the high produced induced residual stress and mechanical property anisotropy associated with the unique microstructures is critical. X-ray and neutron diffraction are considered the benchmark for non-destructive characterization of surface and bulk internal residual stress. The latter, characterized by the high penetration power in most engineering alloys, allows for the use of diffraction angle close to 90° enabling a near cubic sampling volume to be specified. However, the complex microstructures of columnar growth with inherent crystallographic texture typically produced during PBF-LB/M of metallics present significant challenges to the assumptions typically required for time efficient determination of residual stress. These challenges include the selection of an appropriate set of diffraction elastic constants and a representative strain-free reference for the material of interest. In this presentation advancements in the field of diffraction-based residual stress analysis of L-PBF Inconel 718 will be presented. The choice of an appropriate set of diffraction-elastic constants depending on the underlying microstructure will be described.
T2 - MLZ User Meeting 2022
CY - Munich, Germany
DA - 08.12.2022
KW - Diffraction
KW - Residual Stress
KW - Microstructure
KW - Texture
KW - Mechanical behavior
PY - 2022
AN - OPUS4-56804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belli, Renan
A1 - Hartmann, Sabine
A1 - Lubauer, Julia
A1 - Pereira, Raíssa Monteiro
A1 - Hurle, Katrin
A1 - Yin, Ling
A1 - Mieller, Björn
A1 - Lohbauer, Ulrich
T1 - Improving the chipping resistance of pre-sintered zirconia white-bodies
N2 - Objectives: The high occurrence of fractures, cracking and chipping of zirconia pre-sintered blanks and blocks during machining decreases their yield and can transfer lifetime-limiting racks to the final sintered restoration. This study has the objective of characterizing the mechanical and fracture properties of two zirconia compositions while varying temperature and time of pre-sintering, in order to assess the space for possible improvement.
Methods: We selected two typical granular powders with 3 mol% (3YSZ, Zpex®, Tosoh) or 5 mol% (5YSZ, Zpex Smile®, Tosoh) yttria-stabilized zirconia and two pre-sintered commercial analogs (IPS e.max® ZirCAD MO, Ivoclar and Katana™ STML, Kuraray). The debinding and pre-sintering stages of the experimental powders were characterized using thermal analyses (differential scanning calorimetry and thermogravimetry), and the crystal phase composition was quantified using X-ray diffraction (XRD). Physical and mechanical properties such as density, hardness, flexural modulus, biaxial flexural strength and fracture toughness were measured for two pre-sintering temperatures (1000 ◦C, 1100 ◦C) and increasing holding times at those temperatures (2 h, 4 h, 6 h). The chipping resistance for those conditions was quantified using the edge chipping test using a Vickers diamond indenter.
Results: Thermal analyses revealed that both powders show comparable debinding behavior and contained approx. 3.8 mass % organic binder, which burns-out completely between 300 and 400 ◦C. The crystallographic phase changes occurring during the 2–6 h at 1000 ◦C and 1100 ◦C was not detectable in the DSC signal, but quantifiable by XRD. Namely, a major content of monoclinic phase in both powders transforms completely into the two tetragonal phases, starting below 1000 ◦C and concluding above 1100 ◦C. All physical and mechanical properties increased with holding time for both temperatures, though more steeply for pre-sintering at 1100◦C. Edge chipping resistance response was well aligned with other fracture properties, with a more marked improvement for 3YSZ pre-sintered at 1100 ◦C. For all properties, the 3YSZ zirconia showed statistically-higher values for the same temperature-time conditions, in agreement with the values obtained for the commercial materials as well.
Significance: The results demonstrate the weakness of pre-sintered zirconia products concerning fracture properties, but also the potential for improvement as related to type of zirconia and pre-sintering conditions. This study outlines the use of a set of mechanical tests that can characterize chipping resistance and guide future research engaging in optimizing the machining resistance of pre-sintered zirconia products.
KW - Zirconia
KW - Fracture
KW - White body
KW - Dental materials
KW - Pre-sintering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653457
DO - https://doi.org/10.1016/j.dental.2025.12.012
SN - 0109-5641
SP - 1
EP - 12
PB - Elsevier Inc.
AN - OPUS4-65345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jamro, R.
A1 - Mente, Tobias
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Al-Falahat, Ala'A. M.
A1 - Woracek, R.
A1 - Manke, I.
A1 - Griesche, Axel
T1 - Temperature distribution during welding measured by neutron imaging
N2 - This study was carried out to investigate the neutron transmission signal as a function of sample temperature during a welding process. A theoretical description that includes the Debye-Waller factor was used to describe the temperature influence on the neutron crosssections. Neutron imaging using a monochromatic beam helps to observe transmission variations related to the material temperature. In-situ neutron imaging of welding experiments show the distribution of the temperature in bulk steel samples. The performed finite element modelling of expected temperature distributions shows good agreement with the obtained experimental data.
KW - Neutron imaging
KW - Debye-Waller-Faktor
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586268
DO - https://doi.org/10.1088/1742-6596/2605/1/012026
VL - 2605
SP - 1
EP - 10
PB - IOP Publishing Ltd.
AN - OPUS4-58626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Xing, Na
A1 - Er, Jasmin
A1 - Vidal, Ricardo M.
A1 - Khadka, Sandhya
A1 - Schusterbauer, Robert
A1 - Rosentreter, Maik
A1 - Etouki, Ranen
A1 - Ahmed, Rameez
A1 - Page, Taylor
A1 - Nickl, Philip
A1 - Bawadkji, Obida
A1 - Wiesner, Anja
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Ludwig, Kai
A1 - Trimpert, Jakob
A1 - Donskyi, Ievgen
T1 - Scalable covalently functionalized black phosphorus hybrids for broadspectrum virucidal activity
N2 - At the onset of viral outbreaks, broad-spectrum antiviral materials are crucial before specific therapeutics become available. We report scalable, biodegradable black phosphorus (BP) hybrids that provide mutation-resilient virucidal protection. BP sheets, produced via an optimized mechanochemical process, are covalently functionalized with 2-azido-4,6-dichloro- 1,3,5-triazine to form P=N bonds. Fucoidan, a sulfated polysaccharide with intrinsic antiviral activity, and hydrophobic chains are then incorporated to achieve irreversible viral deactivation. The material exhibits strong antiviral inhibition and complete virucidal activity against multiple viruses, including recent severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants. It maintains high biocompatibility, remains effective against viral mutations, and is shelf stable for at least five month. The combination of biodegradability, scalable synthesis, and synergistic antiviral and virucidal mechanisms establishes BP-conjugates as a new class of highly efficient antivirals. They offer a broad spectrum antiviral solutions that could bridge the gap between antiviral medicines and general antiseptics.
KW - Black phosphorus
KW - Antiviral materials
KW - Functionalization
KW - Biodegradability
KW - Sheets
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652941
DO - https://doi.org/10.48550/arXiv.2510.12854
SN - 2331-8422
SP - 1
EP - 22
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-65294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rossi, Andrea
A1 - Corrao, Elena
A1 - Alladio, Eugenio
A1 - Drobne, Damjana
A1 - Hodoroaba, Vasile-Dan
A1 - Jurkschat, Kerstin
A1 - Kononenko, Veno
A1 - Madbouly, Loay Akmal
A1 - Mrkwitschka, Paul
A1 - Yasamin, Nakhli
A1 - Novak, Sara
A1 - Radnik, Jörg
A1 - Saje, Špela
A1 - Santalucia, Rosangela
A1 - Sordello, Fabrizio
A1 - Pellegrino, Francesco
T1 - Multivariate optimization and characterization of graphene oxide via design of experiments and chemometric analysis
N2 - Controlling the structure and properties of graphene oxide (GO) remains a challenge due to the poor reproducibility of conventional synthetic protocols and limited understanding of parameter-property relationships. In this study, we present an integrated analytical framework that combines Design of Experiments (DoE) with chemometric modelling to systematically assess the effects of eight synthesis variables on GO’s physicochemical and functional features. A Plackett–Burman experimental design enabled efficient screening of synthesis conditions, while comprehensive characterization (spanning UV–Vis spectroscopy, XPS, SEM–EDX, TEM–EDX, and XRD) was coupled with multivariate tools (Principal Component Analysis and Multiple Linear Regression) to identify statistically significant correlations between synthetic inputs and material responses. Notably, we demonstrate that UV–Vis spectra can serve as a robust proxy for oxidation state, offering a rapid and accessible alternative to surface-sensitive methods. The approach yields a predictive analytical toolkit for guiding GO synthesis and highlights a generalizable strategy for the rational design of flat nanomaterials. This work supports reproducible, resource-efficient material development aligned with Safe and Sustainable by Design (SSbD) principles.
KW - Graphene oxide
KW - 2D-materials
KW - Design of Experiment
KW - Synthesis
KW - Chemometric analysis
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652576
DO - https://doi.org/10.1016/j.flatc.2025.100988
SN - 2452-2627
VL - 55
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Kömmling, Anja
A1 - Zaghdoudi, Maha
A1 - Ghasem Zadeh Khorasani, Media
A1 - Jaunich, Matthias
T1 - Data-driven nanomechanical study of filled fluoroelastomer aged in air and hydrogen atmosphere
N2 - Fluoroelastomer (FKM) composites are typically used as sealing materials in challenging non-ambient environments. Depending on the environment, two main aging mechanisms, chemical aging, and physical aging, can be identified. Chemical aging, the degradation of the elastomer, is present for example in thermal-oxidative conditions and can be directly observed as it affects the bulk. Physical aging, relaxation and rearrangement of the elastomers segmental conformation is commonly observed at elevated temperatures and effects predominantly the elastomer interphase. As a highly localized nanoscopic effect it is usually observed indirectly by phenomological approaches and not systematically understood. In this study, as a typical example for chemical aging, filled FKM was aged in air (150°C, 100 days). Physical aging of FKM was realized by exposure to chemically inert H2 (150°C, 50 bar, 100 days), since temperature and gas-induced swelling is known to promote physical aging. The effects of both conditions are directly compared with the initial unaged material. We use atomic force microscopy (AFM) force spectroscopy as a method to resolve nanoscopic heterogeneous FKM. With this method the effect of aging on the spatially distinguishable material phases was directly observed. In thermal oxidative aged FKM the matrix shows a decrease in van der Waals interactions and stiffness, indicating dehydrofluorination and chain scission. In H2 aged FKM, the development of an immobilized amorphous interphase (IAP) was observed, indicating physical aging. By additionally evaluating a larger data set with supervised machine learning, these observations were validated for a larger, statistically representative sample area, allowing conclusions to be drawn about the macroscopic behaviour of the material.
KW - Fluoroelastomer
KW - Atomic force microscopy
KW - Data-driven
KW - Hydrogen
KW - Ageing mechanism
KW - Physical aging
KW - Polymer interphase
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648154
DO - https://doi.org/10.1016/j.polymdegradstab.2025.111715
SN - 0141-3910
VL - 242
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-64815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czuban, M.
A1 - Kulka, M. W.
A1 - Wang, L.
A1 - Koliszak, A.
A1 - Achazi, K.
A1 - Schlaich, C.
A1 - Donskyi, Ievgen
A1 - Di Luca, M.
A1 - Mejia Oneto, J. M.
A1 - Royzen, M.
A1 - Haag, R.
A1 - Trampuz, A.
T1 - Titanium coating with mussel inspired polymer and bio-orthogonal chemistry enhances antimicrobial activity against Staphylococcus aureus
N2 - Implant-associated infections present severe and difficult-to-treat complications after surgery, related to implant biofilm colonization. Systemic administration of antibiotics cannot reach sufficient concentrations at the infected site and may be toxic. Here we describe how mussel-inspired dendritic material coated on a titanium surface can locally activate a prodrug of daptomycin (pro-dapto) to treat methicillin-resistant Staphylococcus aureus. The mechanism of the prodrug activation is based on bio-orthogonal click chemistry between a tetrazine (Tz) and trans-cyclooctene (TCO). The former is attached to the dendritic polymer, while the later converts daptomycin into a prodrug. Characterization of the material's properties revealed that it is hydrophobic, non-toxic, and stable for a prolonged period of time. We envision that the titanium coated dendritic material will be able to improve the treatment of implant-associated infections by concentrating systemically administered antibiotic prodrugs, thus converting them into active localized medicines.
KW - Bio-orthogonal chemistry
KW - Antimicrobial titanium coating
KW - Prodrug antibiotic
KW - Antibiotic delivery
KW - Antibiotic release
KW - XPS
PY - 2020
DO - https://doi.org/10.1016/j.msec.2020.111109
VL - 116
SP - 111109
PB - Elsevier B.V.
AN - OPUS4-51204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörenz, Christoph
T1 - Preparation of Nanoparticulate Samples for Electron Microscopy
N2 - This presentation addresses the importance of proper sample preparation to obtain suitable samples for electron microscopic measurements. The objective as well as the requirements are discussed. Further, different sample deposition methods for various types of nanoparticulate samples are shown.
T2 - nPSize Web Conference
CY - Online meeting
DA - 23.07.2020
KW - Nanoparticles
KW - Electron microscopy
KW - Sample preparation
KW - Particle size distribution
KW - Particle number concentration
PY - 2020
AN - OPUS4-51047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chudoba, T.
A1 - Schwenk, D.
A1 - Reinstädt, P.
A1 - Griepentrog, Michael
T1 - High-Precision Calibration of Indenter Area Function and Instrument Compliance
N2 - The accuracy and comparability of nanoindentation results depend significantly on the calibration of area function and instrument compliance. The area function results should not depend on the reference material used or on the calibration method (direct or indirect). This has been investigated for 18 different Berkovich tips. A novel calibration method is proposed that confirms the material independence of the area function and gives a force-dependent instrument compliance function. An agreement between direct and indirect calibration could only be achieved by considering a radial displacement correction. Further, it is shown that the transition range from a spherical cap to the correct face angle of the pyramid can extend to a depth of more than 250 nm. A better parameter for the indenter than the tip radius is the offset of the contact radius to the radius of an ideal tip at a depth where the correct face angle is reached.
KW - Nanoindentation
KW - Calibration
KW - Indenter area function
KW - Instrument compliance
PY - 2022
DO - https://doi.org/10.1007/s11837-022-05291-3
SN - 1047-4838
VL - 74
IS - 6
SP - 2179
EP - 2194
PB - Springer
AN - OPUS4-55849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
T1 - 2020 Microscopy Today Micrograph Awards
N2 - Gold nanocubes with a monodispersed size distribution (edge = 55 nm) deposited on a silicon wafer. These tiny uniform cubes were produced as reference nanoparticles within the EMPIR project nPSize - Improved traceability chain of nanoparticle size measurements. SEM image acquired at 10 kV with an in-lens secondary electron detector. Image colored in ImageJ using LUT “Orange hot.” Published in Microscopy and Microanalysis 25(S2) (2019) 2328.
KW - Nanoparticles
KW - Au-nanocubes
KW - Reference materials
KW - Electron microscopy
PY - 2020
DO - https://doi.org/10.1017/S1551929520001339
VL - 28
IS - 5
SP - 14
EP - 15
PB - Cambridge University Press
CY - Cambridge, UK
AN - OPUS4-51357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
T1 - Oxidative ageing of elastomers: experiment and modelling
N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and an ageing temperature of 125 °C. To exclude possible diffusion limited oxidation (DLO) effects that can distort the data, IRHD micro hardness measurements were performed over the cross-section of compressed O-rings. Continuous stress relaxation measurements were conducted on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments.
T2 - ACEX-14th International Conference on Advanced Computational Engineering and Experimenting
CY - Malta
DA - 04.07.2021
KW - Compression stress relaxation
KW - Compression set
KW - IRHD micro hardness
KW - Modelling
PY - 2021
AN - OPUS4-52968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Chemical and topographical changes upon sub-100-nm LIPSS formation on titanium alloy
N2 - Laser-induced periodic surface structures (LIPSS) have gained remarkable attention as they represent a universal phenomenon that is often accompanying laser-processing. Such LIPSS enable a large variety of different surface functionalizations for applications in the fields of optics, fluidics, tribology, or medicine. Moreover, so-called “high spatial frequency LIPSS” (HSFL) provide an appealing and straightforward way for surface nanostructuring featuring spatial periods even below 100 nm – far beyond the optical diffraction limit. However, the imposed surface functionalities are usually caused by both, topographic and chemical surface alterations. For exploring these effects in detail, multi-method characterizations were performed here for HSFL on processed Ti- 6Al- 4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ~1 ps pulse duration, 1 – 400 kHz pulse repetition rate) under different laser and scan processing conditions. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), stylus profilometry (SP), and white light interference microscopy (WLIM), as well as near-surface chemical analyses by X-ray photoelectron spectroscopy (XPS), hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results allow to qualify the laser ablation depth, the geometrical HSFL characteristics and provide detailed insights into the depth extent and the nature of the ps-laser-induced near-surface oxidation. Significance for medical applications will be outlined.
T2 - E-MRS Spring Meeting 2023
CY - Strasbourg, France
DA - 29.05.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser processing
KW - Hard X-ray photoelectron spectroscopy (HAXPES)
KW - Time-offlight secondary ion mass spectrometry (ToF-SIMS)
KW - Ti6Al4V alloy
PY - 2023
AN - OPUS4-58531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
A1 - Feltin, N.
T1 - Hybrid metrology for microscopy of nanoparticles
N2 - This presentation is structured in two parts: i) Hybrid metrology by combining SEM with AFM (N. Feltin) and ii) hybridization and corelative microscopy by SEM, STEM-in-SEM, TEM, EDS, Auger Electron Microscopy, TKD and more (D. Hodoroaba).
The first part is focused on the metrological part of the hybrid measurement SEM-AFM, the second part offers some further possibilities of correlative microscopy of nanoparticles based on practical examples.
T2 - EMPIR nPSize Training Course "Metrology for Measurement of Nanoparticle Size by Electron Microscopy and Atomic Force Microscopy"
CY - Online meeting
DA - 27.10.2020
KW - Nanoparticles
KW - SEM
KW - AFM
KW - Metrology
KW - Particle size distribution
KW - Correlative imaging
KW - STEM-in-SEM (TSEM)
PY - 2020
AN - OPUS4-51476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Quantitative Microstructural Analaysis under VAMAS/TWA 37
N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 45th Steering Committee Meeting
CY - Online meeting
DA - 30.09.2020
KW - VAMAS
KW - Microbeam analysis
KW - Inter-laboratory comparison
KW - EBSD
KW - FIB
PY - 2020
UR - http://www.vamas.org/
AN - OPUS4-51360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - EMPIR nPSize - Improved Traceability Chain of Nanoparticle Size Measurement; What nPSize can offer after 2Ys?
N2 - The main outcomes of the EMPIR project nPSize are presented and the suitability of the new capabilities (e.g. reference materials, measurement procedures, inter-laboratory comparisons) as pertinent contributions to normative projects within CEN/TC 352 Nanotechnologies are discussed.
T2 - 28th Meeting of CEN/TC 352 Nanotechnologies
CY - Online meeting
DA - 16.10.2020
KW - Nanoparticles
KW - CEN/TC 352 Nanotechnologies
KW - Particle size distribution
KW - Traceability
PY - 2020
AN - OPUS4-51437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beyranvand, S.
A1 - Pourghobadi, Z.
A1 - Sattari, S.
A1 - Soleymani, K.
A1 - Donskyi, Ievgen
A1 - Gharabaghi, M.
A1 - Unger, Wolfgang
A1 - Farjanikish, G.
A1 - Nayebzadeh, H.
A1 - Adeli, M.
T1 - Boronic acid functionalized graphene platforms for diabetic wound
N2 - While noncovalent interactions between graphene derivatives and biosystems are extensively studied, less knowledge about their covalent multivalent interactions at biointerfaces is available. Due to the affinity of boronic acids towards cis-diol bearing biosystems, graphene sheets with this functionality were synthesized and their covalent interactions with the bacteria and nematode were investigated. As expected, graphene platforms with boronic acid functionality were able to wrap bacteria and destroy it in a short time. Surprisingly, body of nematodes was ruptured and their viability decreased to 30% after 24 h incubation with the functionalized graphene sheets. Because of their antibacterial and antiparasitic activities as well as their ability for wound dressing, graphene platforms with the boronic acid functionality were further investigated for diabetic wound healing. In vivo experiments showed that graphene platforms are more efficient than the commercially available drug, phenytoin, and restore both infected and non-infected diabetic wounds in ten days. Taking advantage of their straightforward synthesis, strong interactions with different biosystems as well as their ability to heal diabetic wounds, the boronic Acid functionalized graphene sheets are promising candidates for a broad range of future biomedical applications.
KW - Graphene
KW - Boronic acid
KW - Functionalized graphene
KW - XPS
PY - 2020
UR - https://www.sciencedirect.com/science/article/abs/pii/S0008622319310954
DO - https://doi.org/doi.org/10.1016/j.carbon.2019.10.077
VL - 158
SP - 327
EP - 336
PB - Elsevier Ltd.
AN - OPUS4-50559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Wolfgang
T1 - International standardization and metrology as tools to address the comparability and reproducibility challenges in XPS measurements
N2 - The status of standardization related to x-ray photoelectron spectroscopy (XPS, ESCA) at ASTM International (Subcommittee E42.03) and ISO (TC 201) is presented and commented upon in a structured manner. The survey also identifies other active bodies, here VAMAS Technical Working Area 2 and the Surface Analysis Working Group at the International Meter Convention, contributing to prestandardization Research and metrology of XPS and reports their specific activities. It is concluded that existing standardization is delivering good practices in the use of XPS and has a high potential to avoid the recently observed erroneous use, misapplications, and misinterpretation by new and inexperienced users of the method—which seems to be the main reason for the “reproducibility crisis” in the field of XPS applications. A need for a more proactive publicizing of international documentary standards by experienced XPS users, specifically those who are involved in standardization, is identified. Because the existing portfolio of standards addressing the use of XPS is not complete, future standardization projects planned or already ongoing are mentioned. The way the standardization bodies are identifying future needs is shortly explained.
KW - Standardisation
KW - Comparability
KW - Reproducibility
KW - XPS
KW - VAMAS
KW - Metrology
PY - 2020
DO - https://doi.org/10.1116/1.5131074
VL - 38
IS - 2
SP - 021201-1
EP - 021201-8
PB - AVS
AN - OPUS4-50560
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gollwitzer, C.
T1 - Computation of scattering curves for particles with arbitrary shapes using Debye’s formula
N2 - Small-angle scattering data from particle dispersions with narrow size distributions are usually analysed by fitting a model function to the data, which is composed of a monodisperse form factor with a size distribution and, optionally, a structure factor. For common particle shapes like solid spheres, core-shell particles, ellipsoids or rods, the form factor can be computed analytically, and several software packages are readily available which provide a compilation of form factors.1,2 Recently, highly monodisperse nanoparticles with a variety of shapes have been synthesized, e.g. cubes and bipyramids3,4 with lightly capped edges, for which analytic form factors are harder to derive.
We compute an approximation to the scattering curve of arbitrary shapes by filling the shape with a quasi-random distribution of point scatterers and using Debye’s formula to get the overall scattering curve. The highly optimized debyer code is used to perform an efficient evaluation of Debye’s formula,5 which can perform the evaluation of 500,000 point scatterers in two minutes on commodity hardware. Moderate polydispersity is handled by interpolating the computed scattering curve over q from a master curve. In this way, the code is fast enough to perform data fitting of particle ensembles with moderate polydispersity for arbitrary shapes to experimental data.
This work was partly funded by the 17NRM04 nPSize project of the EMPIR programme co-financed by the EMPIR participating states and by the European Union’s Horizon 2020 research and innovation programme.
T2 - 17th Nordic Workshop on Scattering from Soft Matter
CY - Linköping, Sweden
DA - 14.01.2020
KW - X-ray scattering
KW - Nanoparticles
KW - Particle shape
KW - Modelling
KW - Form factor
PY - 2020
UR - http://nssm2020.se/
AN - OPUS4-50368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Minimale Anforderungen an Referenzdaten anhand von Beispielen aus der Elektronenmikroskopie und Oberflächenanalytik
N2 - In dem Vortrag werden, anhand ausgewählten Beispielen aus der Elektronenmikroskopie und Oberflächenanalytik (EDX und XPS), die minimalen Anforderungen an Referenzdaten für zuverlässige und reproduzierbare Ergebnisse (z.B. Partikelgrößenverteilung, Elementzusammensetzung) vorgestellt und diskutiert.
T2 - Workshop "Referenzdaten"
CY - Berlin, Germany
DA - 13.03.2020
KW - Referenzdaten
KW - Nanopartikel
KW - Elektronenmikroskopie
KW - Oberflächenanalytik
KW - Standardarbeitsanweisung
KW - SOP
KW - Standardisierung
PY - 2020
AN - OPUS4-50571
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - An interlaboratory comparison on measuring the chemical composition of functionalized graphene nanoplatelets
N2 - The results of the international interlaboratory comparison ""Chemical Composition of functionalized graphene with X-ray photoelectron spectroscopy (XPS) under the auspice of VAMAS TWA 2 (Surface Chemical Analysis) will be presented.
T2 - Kratos German User Meeting 2023
CY - Berlin, Germany
DA - 25.10.2023
KW - Graphene
KW - Interlaboratory Comparison
KW - X-ray photoelectron spectroscopy
PY - 2023
AN - OPUS4-58683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Accurate Measurement of Size of Graphene Oxide Flakes by Scanning Electron Microscopy (SEM)
N2 - Accurate characterisation of the morphology (size) and chemistry of graphene-related 2D materials (GR2M) is key in understanding their extraordinary functionalities. Hence, not only the tailoring of these functionalities aiming at applications of increased-performance becomes possible, but also the correlation of the physico-chemical properties with the understanding of the potential toxicity eventually enables a safe and sustainable development of the GR2M for new applications. Whilst AFM and Raman Spectroscopy are recommended to measure the thickness of GO flakes, Scanning Electron Microscopy (SEM) is the most suited method to assess their lateral size, which varies between tens of µm down to below 100 nm. In this paper, procedures for the accurate determination of lateral size of graphene oxide (GO) flakes by SEM are presented. The prerequisite for accurate flake size analysis is the proper sample preparation, i.e. deposition of ideally isolated flakes on a substrate, with the flakes being unfolded, non-overlapped, parallel with the substrate, and having a high coverage density. Examples of optimum image caption conditions and image analysis procedures will be presented. The size descriptors and their measurement are described in the context of the corresponding analysis approach: i) length and width of the flakes with a quick and rough, but robust procedure, and ii) exact contouring of the flakes as part of a highly accurate, but more time-consuming measurement approach. The possibility of application of automated image analysis is discussed as the alternative to the manual flakes analysis.
T2 - Graphene 2023
CY - Manchester, UK
DA - 27.07.2023
KW - Graphene oxide
KW - SEM
KW - Size
KW - Standardisation
PY - 2023
UR - https://www.grapheneconf.com/2023/index.php
AN - OPUS4-57910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cios, Grzegorz
A1 - Hodoroaba, Vasile-Dan
T1 - High throughput nanoparticle analysis using transmission Kikuchi diffraction
N2 - In the present paper we show an approach of measuring large numbers of nanoparticles in a single scan TKD. TiO2 anatase nanoparticles (NP) of bipyramidal shape were deposited on standard carbon grid used for TEM. The procedure used promoted formation of NP ‘monolayer’ islands with uniform distribution of NPs on the carbon surface which allowed mapping of large number of nanoparticles in the single island.
Collection of whole map covering ~2800 nanoparticles took nearly 20 minutes. Inverse pole figure color coded map indicates that the NPs are either lying on a {101} facet (within 10° range around perfect {101} parallel to the carbon surface orientation) on the carbon film or are lying on a {100} facet (within 10° range around the perfect {100} parallel to the carbon surface orientation). Very unlikely was the NP orientation standing on a {001} face. The NPs size distribution described as equivalent circle diameter (ECD) has been also evaluated and the mean NP ECD was 59 nm with standard deviation of 15 nm, i.e. in good agreement with electron microscopy or AFM results.
This study shows high potential of the technique for crystalline NPs analysis with respect to geometrical orientation of the particles on the substrate. With known orientation, the 3D dimensional characterisation of such non-spherical NPs becomes possible from 2D projection electron micrographs. Moreover, the NP size distribution can be easily extracted. Superior accuracies down to 1-2 nm are achievable. The approach is applicable also on thin lamellae extracted from particulate (or mesoporous) layers.
T2 - EMAS 2023 - 17th European Workshop on Modern Developmennts and Applications in Microbeam Analysis
CY - Krakow, Poland
DA - 07.05.2023
KW - Nanoparticles
KW - TKD
KW - Electron microscopy
KW - TiO2
KW - Orientation
PY - 2023
UR - https://www.microbeamanalysis.eu/events/event/60-emas-2023-17th-european-workshop-on-modern-developments-and-applications-in-microbeam-analysis
AN - OPUS4-57519
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS Regional Report Germany
N2 - Regional standardisation activities and how VAMAS can help in any way to promote activities are reported.
Activities related to organisational updates, government initiatives/priorities (especially related to Materials), details of any strategy documents publicly available, networks within Germany and how we engage are presented.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 48th Steering Committee Meeting
CY - New Delhi, India
DA - 09.10.2023
KW - VAMAS
KW - Standardisation
PY - 2023
UR - https://www.nplindia.org/index.php/amcsnzt_2023/
AN - OPUS4-58572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abram, Sarah-Luise
A1 - Mrkwitschka, Paul
A1 - Thünemann, Andreas
A1 - Radnik, Jörg
A1 - Häusler, I.
A1 - Bresch, Harald
A1 - Hodoroaba, Vasile-Dan
A1 - Resch-Genger, Ute
T1 - Iron Oxide Nanocubes as a New Certified Reference Material for Nanoparticle Size Measurements
N2 - The rational design and increasing industrial use of nanomaterials require a reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry. This calls for nanoscale reference materials (nanoRMs) for the validation and standardization of commonly used characterization methods closely matching real-world nonspherical nano-objects. This encouraged us to develop a nonspherical nanoRM of very small size consisting of 8 nm iron oxide nanocubes (BAM-N012) to complement spherical gold, silica, and polymer nanoRMs. In the following, the development and production of this nanoRM are highlighted including the characterization by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) as complementary methods for size and shape parameters, homogeneity and stability studies, and calculation of a complete uncertainty budget of the size features. The determination of the nanocubes’ edge length by TEM and SAXS allows a method comparison. In addition, SAXS measurements can also provide the mean particle number density and the mass concentration. The certified size parameters, area equivalent circular diameter and square edge length, determined by TEM with a relative expanded uncertainty below 9%, are metrologically traceable to a natural constant for length, the very precisely known (111) lattice spacing of silicon. Cubic BAM-N012 qualifies as a certified nanoRM for estimating the precision and trueness, validation, and quality assurance of particle size and shape measurements with electron microscopy and SAXS as well as other sizing methods suitable for nanomaterials. The production of this new iron oxide nanocube RM presents an important achievement for the nanomaterial community, nanomaterial manufacturers, and regulators.
KW - Certification
KW - SAXS
KW - Homogeneity
KW - Nano
KW - Particle
KW - Iron oxide
KW - Quality assurance
KW - Reference material
KW - Size
KW - Electron microscopy
KW - Stability
KW - Shape
PY - 2023
DO - https://doi.org/10.1021/acs.analchem.3c00749
SN - 0003-2700
VL - 95
IS - 33
SP - 12223
EP - 12231
PB - American Chemical Society
CY - Columbus, Ohio
AN - OPUS4-58176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rühle, Bastian
A1 - Hodoroaba, Vasile-Dan
T1 - Automatic Image Segmentation and Analysis using Neural Networks
N2 - We present a workflow for obtaining fully trained artificial neural networks that can perform automatic particle segmentations of agglomerated, non-spherical nanoparticles from electron microscopy images “from scratch”, without the need for large training data sets of manually annotated images. This is achieved by using unsupervised learning for most of the training dataset generation, making heavy use of generative adversarial networks and especially unpaired image-to-image translation via cycle-consistent adversarial networks. The whole process only requires about 15 minutes of hands-on time by a user and can typically be finished within less than 12 hours when training on a single graphics card (GPU). After training, SEM image analysis can be carried out by the artificial neural network within seconds, and the segmented images can be used for automatically extracting and calculating various other particle size and shape descriptors.
T2 - Machine Learning Workshop
CY - Online Meeting
DA - 18.03.2021
KW - Electron Microscopy
KW - Neural Networks
KW - Artificial Intelligence
KW - Image Segmentation
KW - Automated Image Analysis
PY - 2021
AN - OPUS4-52304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chemello, Giovanni
T1 - Characterization of industrial graphene using HAXPES
N2 - A comparative analysis is performed by XPS, HAXPES and SEM of industrial functionalised graphene powder of different morphology. The chemical analysis carried out by XPS, which probing depth is around 10nm, and HAXPES, which can reach up to 30nm probing depth. By combining these two techniques is possible to get a rough, non-destructive depth profiling of the sample's surface. The results show a higher concentration of the functionlisation elements on the surface of the sample and the influence of the morphology on the functionalisation process and the C/O ratio.
T2 - SALSA Make and Measure 2022
CY - Berlin, Germany
DA - 15.09.2022
KW - Graphene
KW - XPS
KW - HAXPES
KW - SEM
KW - Graphene funcionalisation
PY - 2022
AN - OPUS4-55971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaunich, Matthias
T1 - An update on metal seal tests performed at BAM and implications for interim storage
N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung. Metallic seals are in use in interim storage casks for used fuel and high active waste. Their change in performance over time is of high importance for maintaining safe enclosure. Therefore, investigations on these systems were started at BAM to get a general understanding of the relevant processes. Our investigations comprise investigations on different parameters which influence the seal performance and the main part is focussed on the time and temperature dependent behaviour.
In this contribution an update on the performed tests and their respective results will be given in respect to the overview presented in 2020.
The understanding of the long-term behaviour of the sealing systems and the performance evaluation during interim storage and subsequent transportation are our goals.
T2 - SEDS-Workshop: Sicherheit der längerfristigen trockenen Zwischenlagerung
CY - Garching, Germany
DA - 15.05.2024
KW - Metal seals
KW - Ageing
KW - Leakage rate
KW - Creep
PY - 2024
AN - OPUS4-60640
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Mansfeld, Ulrich
A1 - Ortel, Erik
A1 - Mielke, Johannes
A1 - Pellegrino, F.
A1 - Maurino, V.
T1 - Towards 3D Understanding of Non-spherical Nanoparticles by Transmission Kikuchi Diffraction (TKD) for Improved Particle Size Distribution by Electron Microscopy
N2 - In this paper one refined approach is applied to determine the exact orientation of bipyramidal TiO2 nanoparticles prepared with good dispersion as almost isolated particles on a carbon TEM grid. The advantages of the recently developed high-throughput Transmission Kikuchi Diffraction (TKD) are used to identify quickly and reliably the geometrical orientation of the crystalline TiO2 nanoparticle bipyramids (anatase) on a statistically relevant number of particles.
KW - Nanoparticles
KW - Transmission Kikuchi Diffraction (TKD)
KW - Electron microscopy
KW - TiO2
KW - 3D
PY - 2020
DO - https://doi.org/10.1017/S1431927620013999
VL - 26
IS - S2
SP - 260
EP - 261
PB - Cambridge University Press
CY - Cambridge, UK
AN - OPUS4-51772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Miropoltsev, M.
A1 - Wegner, Karl David
A1 - Häusler, I.
A1 - Hodoroaba, Vasile-Dan
A1 - Resch-Genger, Ute
T1 - Influence of Hydrophilic Thiol Ligands of Varying Denticity on the Luminescence Properties and Colloidal Stability of Quaternary Semiconductor Nanocrystals
N2 - Binary photoluminescent semiconductor nanocrystals (quantum dots, QDs) are one of the best studied fluorescent nanomaterials, and their unique optoelectronic properties paved the road to many applications in (bio)nanophotonics, optoelectronics, and photovoltaics. However, concerns related to their toxic constituents like cadmium or lead and the emerging interest in greener chemistry synthesis approaches hamper their future applicability. Interesting alternatives for some applications like biosensing or bioimaging are heavy-metal-free ternary QDs like AgInS2 (AIS), CuInS2 (CIS), and quaternary QDs such as AIS-ZnS (ZAIS). In this context, we explored the effect of ligand denticity on the organic-to-aqueous phase transfer of oleylamine-stabilized ZAIS QDs with the hydrophilic ligands mercaptopropionic acid (MPA), dihydrolipoic acid (DHLA), and 3-mercapto-2,2-bis(mercaptomethyl)propanoic acid (3MPA), bearing mono-, bi-, and trialkyl thiol groups. Spectroscopic studies of the resulting water-dispersible ZAIS QDs revealed a considerable influence of ligand denticity and ligand-to-QD ratio on the spectral position and width (FWHM; full width at half-maximum) of the photoluminescence (PL) bands, the PL quantum yields (PL QY), and the PL decay kinetics. Thiol capping and phase transfer resulted in a loss in PL by at least a factor of 2. The ligand-induced PL quenching observed particularly for ligands bearing two or three thiol groups was attributed to the facilitated formation of surface-bound disulfides. The best colloidal stability under high dilution conditions was observed for 3MPA.
KW - Quantum dots
KW - Ligand exchange
KW - Lifetime analysis
KW - Thiols
PY - 2022
DO - https://doi.org/10.1021/acs.jpcc.2c05342
SN - 1932-7447
VL - 126
IS - 47
SP - 20101
EP - 20113
PB - ACS Publications
AN - OPUS4-56707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Correlative analysis with electron microscopy applied in different operating modes (SEM, STEM-in-SEM and TEM) for the accurate morphological characterisation of non-spherical fine nanoparticles
N2 - Electron microscopy applied in different operating modes, e.g., SEM, TEM or STEM-in-SEM, is the gold standard method to investigate the exact size and shape of individual nanoparticles. However, when fine nanoparticles with a non-monodisperse size distribution and non-spherical shapes are analysed, achieving an accurate result is challenging. Deviations in size measurements of more than 10% may occur. Understanding of the contrasts and sensitivities characteristic to the individual operating modes of an electron microscope is key in interpreting and evaluating quantitatively the measurement uncertainties needed for an eventual certification of specific nanoparticles via traceable results. Further, beyond the pure measurement, the other components in the analysis workflow with significant impact on the overall measurement uncertainties are the sample preparation and the image segmentation. In the present study the same areas of selected iron oxide fine nanoparticles (<25 nm) as reference nanomaterial (candidate) prepared on substrate for electron microscopy imaging are analysed correlatively with SEM, STEM-in-SEM and TEM with respect to their size and shape distribution. Individual significant measurement uncertainties are discussed, e.g., the sensitivity of secondary electron detectors of InLens-type to the surface morphology, particularly to the presence of an ultrathin organic coating or signal saturation effects on the particle edges, to electron beam exposure, to surface contamination, or the selection of the threshold for image segmentation. Another goal of this study is to establish a basis of analysis conditions which shall guarantee accurate results when both manual and particularly (semi-)automated segmentation approaches are applied. Advantages as well as limitations of the use of different electron microscopy operating modes, applied individually and correlatively, are highlighted.
T2 - E-MRS 2024 Spring Meeting
CY - Strasbourg, France
DA - 27.05.2024
KW - Nanoparticles
KW - Electron Microscopy
KW - Metrology
KW - Imaging
KW - Reference materials
PY - 2024
AN - OPUS4-60436
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
A1 - Hodoroaba, Vasile-Dan
T1 - Understanding Correlative Electron Microscopy Imaging with SEM, STEM in SEM and TEM for the Accurate Characterization of Size and Shape of FeOx Nanoparticles
N2 - The recently certified reference material (CRM) BAM-N012 as cubical iron oxide FeOx nanoparticles (NPs) of 8 nm area equivalent square edge length (ESL) and the RM candidate BAM-N013 as nearly spherical NPs of 22 nm size were analyzed in detail by electron microscopy (EM).
For the metrological characterization with SEM, STEM in SEM and TEM, the understanding of the imaging contrasts and sensitivities, and the correct interpretation of the (art)effects which are inherent to each detection mode is necessary.
The same sample areas with NPs deposited on a TEM grid were analyzed by two SEM acquisition modes, i. e. SE InLens and STEM in SEM using a dedicated transmission sample holder, and further, correlatively, analyzed with TEM.
With increasing kV, SE InLens shows increasing particle size (unless overcharging at the particle boundaries is filtered), as a known effect. For STEM-in-SEM the particle size decreases significantly and individual particles are identified easier (at 2 kV only a few single particles can be detected automatically).
❑ Documentation of the sample preparation and measurement conditions (including optimization process) is important for reproducibility.
❑ Plasma cleaning, analysis in the transmission mode at SEM is recommended for FeOx NPs.
❑ Selection of the threshold algorithm can significantly alter the reported ECD.
T2 - Microscopy and Microanalysis 2024
CY - Cleveland, OH, USA
DA - 28.07.2024
KW - Nanoparticles
KW - Electron microscopy
KW - Iron oxide
KW - Reference materials
KW - Correlative microscopy
KW - Size and shape distribution
PY - 2024
AN - OPUS4-60806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Understanding Correlative Electron Microscopy Imaging with SEM, STEM-in-SEM and TEM for the Accurate Characterization of Size and Shape of FeOx Nanoparticles
N2 - The recently certified reference material (CRM) BAM-N012 as cubical iron oxide FeOx nanoparticles (NPs) of 8 nm area equivalent square edge length (ESL) and the RM candidate BAM-N013 as nearly spherical NPs of 22 nm size were analyzed in detail by electron microscopy (EM).
For the metrological characterization with SEM, STEM in SEM and TEM, the understanding of the imaging contrasts and sensitivities, and the correct interpretation of the (art)effects which are inherent to each detection mode is necessary.
The same sample areas with NPs deposited on a TEM grid were analyzed by two SEM acquisition modes, i. e. SE InLens and STEM in SEM using a dedicated transmission sample holder, and further, correlatively, analyzed with TEM.
With increasing kV, SE InLens shows increasing particle size (unless overcharging at the particle boundaries is filtered), as a known effect. For STEM-in-SEM the particle size decreases significantly and individual particles are identified easier (at 2 kV only a few single particles can be detected automatically).
❑ Documentation of the sample preparation and measurement conditions (including optimization process) is important for reproducibility.
❑ Plasma cleaning, analysis in the transmission mode at SEM is recommended for FeOx NPs.
❑ Selection of the threshold algorithm can significantly alter the reported ECD.
T2 - SALSA Make and Measure 2024: Interfaces
CY - Berlin, Germany
DA - 11.09.2024
KW - Correlative microscopy
KW - Electron microscopy
KW - Iron oxide
KW - Nanoparticles
KW - Reference materials
KW - Size and shape distribution
PY - 2024
AN - OPUS4-62347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Understanding Correlative Electron Microscopy Imaging with SEM, STEM in SEM and TEM for the Accurate Characterization of Size and Shape of FeOx Nanoparticles
N2 - The recently certified reference material (CRM) BAM-N012 as cubical iron oxide FeOx nanoparticles (NPs) of 8 nm area equivalent square edge length (ESL) and the RM candidate BAM-N013 as nearly spherical NPs of 22 nm size were analyzed in detail by electron microscopy (EM).
For the metrological characterization with SEM, STEM in SEM and TEM, the understanding of the imaging contrasts and sensitivities, and the correct interpretation of the (art)effects which are inherent to each detection mode is necessary.
The same sample areas with NPs deposited on a TEM grid were analyzed by two SEM acquisition modes, i. e. SE InLens and STEM in SEM using a dedicated transmission sample holder, and further, correlatively, analyzed with TEM.
With increasing kV, SE InLens shows increasing particle size (unless overcharging at the particle boundaries is filtered), as a known effect. For STEM-in-SEM the particle size decreases significantly and individual particles are identified easier (at 2 kV only a few single particles can be detected automatically).
❑ Documentation of the sample preparation and measurement conditions (including optimization process) is important for reproducibility.
❑ Plasma cleaning, analysis in the transmission mode at SEM is recommended for FeOx NPs.
❑ Selection of the threshold algorithm can significantly alter the reported ECD
T2 - 2. Treffen des DGE-Arbeitskreises SEM
CY - Stuttgart, Germany
DA - 26.09.2024
KW - Correlative microscopy
KW - Electron microscopy
KW - Iron oxide
KW - Nanoparticles
KW - Reference materials
KW - Size and shape distribution
PY - 2024
AN - OPUS4-62349
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ankli, P.P.
A1 - Ali, A.
A1 - Hodzic, S.
A1 - Logachov, A.
A1 - Maciejczuk, K.
A1 - Milochiv, A.
A1 - Hardy, S.
A1 - Hardy, B.
A1 - Novak, S.
A1 - Kranjc, E.
A1 - Kononenko, V.
A1 - Saje, S.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
A1 - Akmal, Loay
A1 - Mrkwitschka, Paul
A1 - Pellegrino, F.
A1 - Rossi, A.
A1 - Alladio, E.
A1 - Sordello, F.
A1 - Gulumian, M.
A1 - Valsami-Jones, E.
A1 - Andraos, C.
A1 - Wepener, V.
A1 - Jurkschat, K.
A1 - Jones, E.
A1 - Singh, D.
A1 - Ibrahim, B.
A1 - van der Zande, M.
A1 - Fernandez-Poulussen, D.
A1 - Queipo, P.
A1 - Drobne, D.
T1 - Data management for image-based characterisation of 2D nano-materials
N2 - The ACCORDs project, funded through Horizon Europe, is pioneering a novel approach to investigate Graphene Family Materials (GFMs) through image analysis. Our aim is to unveil how these materials might influence health and the environment. To achieve this, we are developing a platform designed for the easy retrieval, access, sharing, and utilisation of GFM data and the coordination between biological and physico-chemical data formats. Integral to this platform is an OMERO-based library for image storage, alongside data collection forms and image analysis tools. Efforts are underway to streamline the process for researchers to upload and disseminate their findings, manage information within a database and navigate the data with ease. Adhering to REMBI guidelines, which set the standard for annotating biological images with metadata, we ensure our data collection is comprehensive and adheres to established best practices. Initially, we are employing thresholding and basic machine learning techniques for image segmentation, laying the groundwork for advanced analysis through deep learning to gain more profound insights. Upon completion, the project will deliver a comprehensive platform facilitating efficient data and image management concerning GFMs. This platform will enable the straightforward discovery and use of protocols and results, all organised in accordance with the FAIR principles – Findable, Accessible, Interoperable, and Reusable.
This initiative is poised to significantly impact materials science, enhancing our comprehension of the safety and environmental implications of 2D materials.
KW - Graphene
KW - Image analysis
KW - Data management
PY - 2024
DO - https://doi.org/10.1016/j.toxlet.2024.07.655
VL - 399
SP - S271
PB - Elsevier B.V.
AN - OPUS4-61011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Towards hydrogen economy: multimethod analysis and operando investigation of mesoporous iridium oxides films for electrocatalysis, EMPIR/EURAMET Project HyMet 16ENG03
N2 - In the face of rising energy demand and the impending climate change the development of a sustainable, fossil-free fuel and chemical production is of global importance. One possible goal is the development of electrochemical conversion processes using catalysts. Porous materials play an important role in such energy applications. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physico-chemical properties. However, the complex morphology of such catalysts constitutes a challenge even for modern analytical techniques. Spectroscopic ellipsometry (SE) is a versatile method for studying material properties by using appropriate models (e.g. film thickness, optical and electronic properties). The fact that the material properties cannot be taken directly from the measured spectra, the developed models have to be validated. In a first step, the model for the ellipsometric fit studies of a calcination series of mesoporous iridium oxide films (300 – 600 °C) was investigated and validated with respect to their material properties. Moreover, the electronic structures of the catalysts reveal a direct correlation with electrochemical activities. The development of an environmental cell offers the possibility of investigations under real conditions. This will allow changes in the optical and electronic properties during the electrocatalytic oxygen evolution reaction.
T2 - HyMet dissemination event
CY - Online meeting
DA - 17.11.2020
KW - Correlative ex-situ ellipsometric analysis
KW - Ellipsometric operando investigation
KW - Hydrogen economy
KW - Mesoporous iridium oxides films
KW - Oxygen evolution reaction
PY - 2020
AN - OPUS4-51629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
T1 - You Ask – ACEnano Replies
N2 - The workshop starts with introductory information about the workshop and the H2020 project ACEnano, followed by two expert round tables, focussing on how the project could address regulator and industry needs, respectively. This is be followed by parallel sessions on tools (based on preferences expressed by those registered to attend, see “Questions”) and finally a question-and-answer session with the attendees.
The experts invited in Round Table 1 have been prepared to answer to questions related to obstacles and advantages for stakeholders such as SMEs to use the ACEnano approaches/tools. Standardisation needs are discussed.
T2 - nanoSafety Cluster Training (NSC) Day @ NanoSAFE 2020: ACEnano users’ workshop “You Ask – ACEnano Replies”
CY - Online meeting
DA - 23.11.2020
KW - ACEnano
KW - Standardisation
KW - Nanomaterials
KW - Nano-characterisation
PY - 2020
UR - https://www.nanosafetycluster.eu/
SP - 1
EP - 2
AN - OPUS4-51693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörenz, Christoph
T1 - Improved Sample Preparation for the Analysis of Nanoparticles by Electron Microscopy
N2 - In this work, we present various promising sample preparation procedures aiming to avoid drying artifacts and guarantee homogeneously distributed NP samples for imaging techniques like TEM, SEM or AFM. This involves retarded drying in an environment of high relative humidity as well as spin coating or freeze drying of the sample on the substrate.
Depending on the type of the NPs, different techniques are successful in obtaining homogenous sample deposition. Simple drying at ambient conditions often results in heavily agglomerated NPs densely packed in coffee ring traces. Retardation of the drying speed in an environment of high relative humidity, however, yields homogeneous NP deposition in the case of bimodal SiO2 and bimodal gold NP’s. In contrast, a sample of bipyramidal TiO2, heavily agglomerated when commonly dried, is successfully dispersed by spin coating the suspension on the substrate. The analysis of the particle size distribution of the bimodal silica and gold samples yielded number ratios resembling the nominal number ratios. The reliable measurement of the NP concentration of polydisperse samples by electron microscopy, even if relative, is new and of special relevance because up to now only the size of the particles, i.e. the abscissa of the PSD, can be measured reliably.
T2 - NANOSAFE 2020
CY - Online meeting
DA - 16.11.2020
KW - Nanoparticles
KW - Particle size distribution
KW - Electron microscopy
KW - Bimodal
KW - SiO2
KW - Gold
PY - 2020
AN - OPUS4-51714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bennet, Francesca
T1 - Towards a method for quantitative evaluation of nanoparticles in suspension via Microprinting and SEM analysis
N2 - A series of different nanoparticle suspensions (Gold, Latex, and SiO2 in varying concentrations) were microprinted onto TEM grids in a 4 x 4 array in the concentration range 7x10^8 to 1x10^11 NP/mL and imaged with SEM and TSEM. Concentrations and printing conditions (temperature, relative humidity) were varied in order to minimize the coffee ring effect.
T2 - nanoSAFE 2020
CY - Online meeting
DA - 16.11.2020
KW - Nanoparticles
KW - Microprinting
KW - Image analysis
PY - 2020
AN - OPUS4-51699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hülagü, Deniz
A1 - Tobias, Charlie
A1 - Dao, Radek
A1 - Komarov, Pavel
A1 - Rurack, Knut
A1 - Hodoroaba, Vasile-Dan
T1 - Towards 3D determination of the surface roughness of core–shell microparticles as a routine quality control procedure by scanning electron microscopy
N2 - AbstractRecently, we have developed an algorithm to quantitatively evaluate the roughness of spherical microparticles using scanning electron microscopy (SEM) images. The algorithm calculates the root-mean-squared profile roughness (RMS-RQ) of a single particle by analyzing the particle’s boundary. The information extracted from a single SEM image yields however only two-dimensional (2D) profile roughness data from the horizontal plane of a particle. The present study offers a practical procedure and the necessary software tools to gain quasi three-dimensional (3D) information from 2D particle contours recorded at different particle inclinations by tilting the sample (stage). This new approach was tested on a set of polystyrene core-iron oxide shell-silica shell particles as few micrometer-sized beads with different (tailored) surface roughness, providing the proof of principle that validates the applicability of the proposed method. SEM images of these particles were analyzed by the latest version of the developed algorithm, which allows to determine the analysis of particles in terms of roughness both within a batch and across the batches as a routine quality control procedure. A separate set of particles has been analyzed by atomic force microscopy (AFM) as a powerful complementary surface analysis technique integrated into SEM, and the roughness results have been compared.
KW - Core–shell particles
KW - Image analysis
KW - Roughness
KW - Scanning electron microscopy
KW - Atomic force microscopy
KW - Tilting
KW - Batch analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607590
DO - https://doi.org/10.1038/s41598-024-68797-7
SN - 2045-2322
VL - 14
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-60759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Kai
A1 - Mirabella, Francesca
A1 - Knigge, Xenia
A1 - Mezera, Marek
A1 - Weise, Matthias
A1 - Sahre, Mario
A1 - Wasmuth, Karsten
A1 - Voss, Heike
A1 - Hertwig, Andreas
A1 - Krüger, Jörg
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Bonse, Jörn
T1 - Chemical and topographical changes upon sub-100-nm laser-induced periodic surface structure formation on titanium alloy: the influence of laser pulse repetition rate and number of over-scans
N2 - Titanium and its alloys are known to allow the straightforward laser-based manufacturing of ordered surface nanostructures, so-called high spatial frequency laser-induced periodic surface structures (HSFL). These structures exhibit sub-100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, multi-method characterizations were performed here for HSFL processed on Ti–6Al–4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm, ≈1 ps pulse duration, 1–400 kHz) under different laser scan processing conditions, i.e., by systematically varying the pulse repetition frequency and the number of laser irradiation passes. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), tactile stylus profilometry, as well as near-surface chemical analyses hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (ToF-SIMS). This provides a quantification of the laser ablation depth, the geometrical HSFL characteristics and enables new insights into the depth extent and the nature of the non-ablative laser-induced near-surface oxidation accompanying these nanostructures. This allows to answer the questions how the processing of HSFL can be industrially scaled up, and whether the latter is limited by heat-accumulation effects.
T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
KW - Laser processing
KW - Hard X-ray photoelectron spectroscopy (HAXPES)
KW - Time-of-flight secondary ion mass spectrometry (ToF-SIMS)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589902
UR - https://onlinelibrary.wiley.com/doi/full/10.1002/pssa.202300719
DO - https://doi.org/10.1002/pssa.202300719
SN - 1862-6319
VL - 221
IS - 15
SP - 1
EP - 12
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-58990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Bütefisch, Sebastian
A1 - Weimann, Thomas
A1 - Hodoroaba, Vasile-Dan
T1 - A New XPS Test Material for More Reliable Analysis of Microstructures
N2 - A reference material is required for small‐area XPS because it has been used more frequently for surface control in recent years and many operators use incorrect field of views. To address this problem, we developed a test material starting in 2019. We optimised this XPS test material dedicated to the control of analysis position on the sample, with respect to the following factors: type of XPS instruments available on the market, the manufacturing process and sample handling. Test structures are now aligned along lines instead of on a circle radius, so that the individual structures can be accessed more quickly and easily. In addition, a larger test structure of 300 μm and another one in an intermediate size of 18 μm were added. Smaller test structures under 50 μm have been annotated with finder grids/arrows around them so that they are easier to find. Further, the manufacturing process was changed from e‐beam lithography to a mask process to be able to offer the test material at a favourable price. The use of masks also had to be adapted for the new manufacturing process so that the smallest square structures are also realised as such and do not show any distortion of the structure boundaries. The quality control using a metrological SEM confirmed a very reproducible manufacturing process. It is demonstrated that the test material can be successfully employed to find the most suitable beam size of the XPS system used for the analysis of small (μm range) surface features.
KW - Small-area measurements
KW - Test material
KW - XPS
KW - XPS imaging
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616577
DO - https://doi.org/10.1002/sia.7367
SP - 1
EP - 6
PB - Wiley
AN - OPUS4-61657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Wolfgang
A1 - Fujimoto, T.
T1 - The Surface Analysis Working Group at the Consultative Committee for Amount of Substance, Metrology in Chemistry and Biology: A successful initiative by Martin Seah
N2 - Dr Martin Seah, NPL, was the initiator, founder, and first chairman of the Surface Analysis Working Group (SAWG) at the Consultative Committee for Amount of Substance, Metrology in Chemistry and Biology (CCQM) at the Bureau International des Poids et Mesures (BIPM), the international organization established by the Metre Convention. This tribute letter summarizes his achievements during his chairmanship and his long-running impact on the successful work of the group after his retirement.
KW - CCQM (Consultative Committee for Amount of Substance)
KW - Metrology in Chemistry and Biology
KW - Martin Seah
KW - Metrology
KW - Quantitative surface chemical analysis
KW - Surface Analysis Working Group
PY - 2021
DO - https://doi.org/10.1002/sia.7033
SN - 0142-2421
VL - 54
IS - 4
SP - 314
EP - 319
PB - John Wiley & Sons Ltd
AN - OPUS4-53714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Minimum Requirements for Nanomaterial Data - Examples with Electron Microscopy and Energy-Dispersive X-Ray Spectroscopy
N2 - In dem Vortrag werden, anhand ausgewählten Beispielen aus der Elektronenmikroskopie und EDX-Elementanalyse, die minimalen Anforderungen an Referenzdaten für zuverlässige und reproduzierbare Ergebnisse (z.B. Partikelgrößenverteilung, Elementzusammensetzung) bei der Charakterisierung von Nanomaterialien vorgestellt und diskutiert.
N2 - Based on practical examples of analysis with Electron Microscopy and Energy-Dispersive X-ray Spectroscopy, the minimum information requirements for reliable and reproducible nanomaterial characterization data such as particle size and shape distribution and elemental analysis are presented and discussed.
T2 - nano@BAM-Workshop Digitalisierung in der Nanosicherheit
CY - Online meeting
DA - 04.12.2020
KW - Nanoparticles
KW - Electron microscopy
KW - EDX
KW - Reference data
KW - Reproducibility
KW - Standardisation
PY - 2020
AN - OPUS4-51775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Übersicht über laufende Untersuchungen zur Langzeitalterung von Elastomerdichtungen
N2 - Eine Aufgabe des Fachbereichs 3.4 Sicherheit von Lagerbehältern der Bundesanstalt für Materialforschung und -prüfung (BAM) ist es, die Sicherheit von Behältern zur Lagerung von radioaktivem Abfall mit vernachlässigbarer Wärmeentwicklung zu bewerten. Da solche Behälter vor der Entsorgung transportiert und gelagert werden, ist während dieser Zeit ein sicherer Einschluss des radioaktiven Inhalts von größter Bedeutung. Zur Abdichtung dieser Behälter sind Elastomer-O-Ringe weit verbreitet. Um für solche, wie auch für viele andere Anwendungen, eine Voraussage über die Lebensdauer dieser Komponenten treffen zu können, ist es unerlässlich zu verstehen, welchen Einfluss der durch Alterung hervorgerufene Abbau auf Dauer auf die Elastomerdichtungen hat. In einem Langzeittest wurden drei Kautschukarten (EPDM und FKM, die für die Anwendung relevant sind, und HNBR als Vergleich) über mehrere Jahre untersucht. Dabei wurden die Veränderungen der mechanischen Eigenschaften (z. B. Härte und Bruchdehnung) bei vier verschiedenen Alterungstemperaturen (75 °C, 100 °C, 125 °C und 150 °C) sowie das Dichtungsverhalten betrachtet. Um den Einfluss von Vernetzung und Kettenspaltung auf die beobachteten Alterungseffekte zu bestimmen, wurden Messungen zur kontinuierlichen und intermittierenden Druckspannungsrelaxation durchgeführt. Dadurch konnten Erkenntnisse über Kinetik und Mechanismus der Abbaureaktionen
gewonnen werden. Zur Einschätzung des Dichtungsverhaltens wurden Durckverformungsrest und Leckagerate gemessen. Die Ergebnisse zeigen, dass die O-Ringe unter statischen Bedingungen auch dann dicht halten, wenn die Werte für Druckverformungsrest, Druckspannungsrelaxation und mechanische Eigenschaften schon auf einen fortgeschrittenen Alterungsabbau hindeuten. Aus diesem Grund wurde ein modifizierter Dichtigkeitsversuch mit einer geringen und schnellen teilweisen Entlastung der Dichtung entwickelt, mit dessen Hilfe sich ein Lebensdauerkriterium bestimmen lässt, das eine Sicherheitsspanne für thermische Schrumpfung und Vibrationen beinhaltet.
KW - Alterung
KW - O-ring
KW - Elastomer Dichtung
PY - 2020
SN - 0176-1625
VL - 73
IS - 07-08
SP - 326
EP - 332
PB - Gupta
CY - Ratingen
AN - OPUS4-51207
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
A1 - Albouy, P.-A.
A1 - Häcker, Ralf
A1 - Stock, Daniel
T1 - Overview of ongoing research and future prospects on polyethylene neutron shielding materials at bam
N2 - The extension of the interim storage period of radioactive waste before disposal will cause additional challenges for the nuclear waste management in Germany, so that an extensive knowledge of the long-term performance of casks, including their components and inventories, will be required for future extended storage licenses.
Ultra-high and high molecular weight polyethylenes ((U)HMW-PE) are used for neutron shielding purposes in casks for storage and transport of spent fuel and high-level waste due to their extremely high hydrogen content. During their service life of several decades as cask components, the PE materials are exposed to neutron and gamma radiation from the radioactive inventory of the casks, mechanical assembling stresses and temperature. All these combined effects affect the material properties of such components which in turn may be crucial for some possible accident scenarios.
At the Bundesanstalt für Materialforschung und -prüfung (BAM), the effects of high temperature exposure in combination with subsequent or previous irradiation were investigated with a comprehensive aging program including thermal aging at 125 °C for different aging periods up to 5 years and irradiation with doses ranging from 50 to 600 kGy.
This contribution provides an overview of the ongoing research related to the structural changes of (U)HMW-PE induced by gamma irradiation and high temperature exposure and focuses on current research perspectives at BAM with regard to the prediction of the dynamic behavior of the material during extended interim storage in case of an accident scenario. First results of the coupled effect of temperature, radiation and mechanical loading will be presented. The effect of microstructural changes induced by gamma irradiation and high temperature on the mechanical behavior of (U)HMW-PE will be assessed.
T2 - PATRAM22
CY - Juan-Les-Pins, Antibes, France
DA - 11.06.2023
KW - (U)HMWPE
KW - Ageing
KW - Irradiation
KW - WAXD
KW - SHPB
PY - 2023
SP - 1
EP - 10
AN - OPUS4-57707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - The role of Critical Raw Materials in Advanced Materials for the Energy Transition
N2 - The energy transition needs advanced materials, especially for batteries, solar cells, and fuel cells. Therefore, critical raw materials are necessary. In this presentation the use of critcal raw materials and strategies for the optimisation of their use are discussed.
T2 - Critical Raw Material Workshop during VAMAS Annual Meeting
CY - Teddington, United Kingdom
DA - 17.09.2025
KW - Advanced solar cells
KW - Iridium oxide
KW - Aerogels
KW - Advanced carbon materials
PY - 2025
AN - OPUS4-64290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chemello, Giovanni
T1 - Analysis of industrial graphene-based flakes – first results on morphological characterization, sample preparation and chemical composition
N2 - Before industrial grade graphene could reach comparable quality to the controlled laboratory scale material, many challenges must be overcome. In order to bridge the gap between lab-scale and industrial-scale production is necessary to develop processes, equipment and measurement procedures to control the material features. One of the most crucial reasons of graphene’s limited commercialization is the lack of standard procedures to properly characterize and define the material chemical and structural properties down to the nanometer level. This leads to many issues regarding material synthesis repeatability, inappropriateness choice of measurands and measurement reproducibility which heavily affect the consistency of the material performance. For example, among all the different industrially produced real-world graphene, it is crucial to determine how many layers of graphene build the material. Products that are built by more than 10 layers should be more correctly referred as nanosized graphite, a problem that is often regarded as the “fake graphene” issue.
In our study, a comparative analysis is performed on two different series (G5 and G6) of industrial graphene powders, each series produced with four types of functionalization: raw graphene, oxygen-functionalized, nitrogen-functionalized and fluorine-functionalized. All the 8 sample variants were analyzed from a chemical and morphological point of view in the form of powders prepared as slightly pressed in metallic sample holders.
The results of the comparative chemical analyses XPS and EDS show a good agreement in the concentration values for all the elements present in the samples, despite the different analysis volumes addressed by the two techniques. For this reason, the samples can be considered homogeneous in both lateral and vertical direction.
A clear influence of the morphology on the composition is evident. Therefore, such correlative measurements of morphology and composition are necessary for a comprehensive characterization of industrial graphene flakes. Protocols for reliable characterization of industrial graphene flakes are in progress.
T2 - Microscopy and Microanalysis 2022
CY - Portland, OR, USA
DA - 31.07.2022
KW - Graphene powder
KW - Functionalized graphene
KW - XPS
KW - SEM
KW - EDS
PY - 2022
AN - OPUS4-55479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rühle, Bastian
A1 - Krumrey, Julian Frederic
A1 - Hodoroaba, Vasile-Dan
T1 - Dataset accompanying the publication "Workflow towards automated segmentation of agglomerated, non-spherical particles from electron microscopy images using artificial neural networks"
N2 - This dataset accompanies the following publication, first published in Scientific Reports (www.nature.com/articles/s41598-021-84287-6):
B. Ruehle, J. Krumrey, V.-D. Hodoroaba, Scientific Reports, Workflow towards Automated Segmentation of Agglomerated, Non-Spherical Particles from Electron Microscopy Images using Artificial Neural Networks, DOI: 10.1038/s41598-021-84287-6
It contains electron microscopy micrographs of TiO2 particles, the corresponding segmentation masks, and their classifications into different categories depending on their visibility/occlusion. Please refer to the publication and its supporting information for more details on the acquisition and contents of the dataset, as well as the GitHub repository at https://github.com/BAMresearch/automatic-sem-image-segmentation
KW - Electron microscopy
KW - Neural networks
KW - Image segmentation
KW - Automated image analysis
PY - 2021
DO - https://doi.org/10.5281/zenodo.4563942
PB - Zenodo
CY - Geneva
AN - OPUS4-52246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Transmission and Scanning Electron Microscopy (SEM/TEM)
N2 - Die Bestimmung der Nanopartikelgrößen- und -formverteilung nach OECD TG 125 mit der Transmission and Scanning Electron Microscopy (SEM/TEM) wird punktuell vorgestellt:
- Generelles Messprinzip
- Beispiele
- Korrelative Mikroskopie
- Welchen Durchmesser misst die Methode?
- Welche Partikel kann diese Methode messen?
- Welche Informationen kann diese Methode liefern?
- Wo stößt die Methode an ihre Grenzen?
- Implementierung und Datenauswertung,
- Reporting.
Anschließend wurde eine Q&A-Session für die Imaging-Methoden organisiert.
T2 - Digital Info-Days „Nano or not Nano“ - Measuring according to OECD Test Guideline No. 125
CY - Online meeting
DA - 16.02.2023
KW - Nanoparticles
KW - OECD TG 125
KW - Partikelgrößenverteilung
KW - Elektronenmikroskopie
PY - 2023
UR - https://www.bam-akademie.de/kursangebot/kurs/digitale-info-tage-%E2%80%9Enano-or-not-nano%E2%80%9C-19.html
AN - OPUS4-57217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Towards automated analysis of the lateral dimensions of graphene oxide flakes
N2 - Graphene and graphene-oxide (GO) are advanced materials which – similar to other graphene-related 2D materials (GR-2M) - are already used for instance in catalysis processes, biomedical applications, in inks and resins, or as composite materials for the aviation industry. The lateral/structural characterization of graphene oxide (GO) flakes is a challenging task, with steps like sample preparation, representative image selection and exact determination of the particle size distribution of well-defined size and shape descriptors being crucial for an accurate analysis. To ensure that safe-by-design principles are met within the various application fields, the commercial material must be thoroughly characterized and specified through well-known and standardized procedures.
GO flakes with different degrees of complexity were selected to assess the requirements for an accurate evaluation of their physico-chemical properties. These samples show inherent features with complex nanoscale characteristics such as porosity and edge roughness; further, the lateral size (quantified via equivalent circular diameter (ECD), minimum Feret and maximum Feret) of isolated and overlapping particles deposited on a substrate span over several orders of magnitude (nano to micron scale). The samples showed different degrees of agglomeration (and possible aggregation) with sizes ranging between submicron to a few tens of micrometers.
One focus is the automated segmentation and evaluation of images obtained by electron microscopy. The GO samples appear translucent with well-defined contrast between single and overlapping flakes both with the secondary electron detector of type InLens as well as with SEM in the transmission mode (STEM) utilizing a dedicated sample holder. To this end it is of utmost importance for the accurate image segmentation to carefully select thresholds both manually and through semi-automatic approaches using well-known threshold algorithms such as “IsoData” and pre-defined segmentation applications such as the ParticleSizer software package.
Further specific challenges in identifying and extracting key features of selected graphene oxide flakes are being discussed and approaches towards accurate and representative characterization are presented.
T2 - E-MRS 2024 Spring Meeting
CY - Strasbourg, France
DA - 27.05.2024
KW - Graphene /-oxide
KW - Morphology
KW - Electron microscopy
KW - Imaging
KW - Advanced materials
PY - 2024
AN - OPUS4-60435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Mühlbauer, Michaela
A1 - Rossi, Andrea
A1 - Pellegrino, Francesco
A1 - Zurutuza, Amaia
A1 - Radnik, Jörg
A1 - Meier, Florian
A1 - Hodoroaba, Vasile-Dan
T1 - Morphological Analysis of Graphene Oxide by Scanning Electron Microscopy and Correlative Field-flow Fractionation Coupled with Multi-angle Light Scattering
N2 - In this paper graphene related 2D materials (GR2M) arre investigated by centrifugal field flow fractioning (CF3) and SEM. Three materials were selected as case studies (CS): graphene „HD-G (CS I), graphene oxide UniTo“ (CS II), and graphene oxide „Graphenea“ (CS III). For CS I particles were evaluated as constituent particles in agglomerates, for the other two materials only isolated (non aggregated/agglomerated) flakes were considered for determination of the area equivalent circular diameter (ECD).
Size analysis of all three materials was carried out by CF3 coupled with MALS (Multi-Angle Light Scattering). For evaluation, it was found that the data obtained was best suited to a disc model. Results are in good agreement when compared to the sizes obtained before CF3 analysis. CS II material is too heterogenous to accurately determine flake size by imaging. CF3 coupled with MALS enables to assess fractions within the highly heterogenous material of CS II.
Imaging of the material in CS III after CF3 measurement indicates that the procedure is non-destructive. This could not be verified for the CS‘s I & II
As a next step we plan to analyse the fractionated samples by imaging them within a SEM wet-cell.
KW - 2D Materials
KW - SEM
KW - Centrifugal field flow fractionation (CF3)
KW - Imaging
KW - Size distribution
PY - 2025
DO - https://doi.org/10.1093/mam/ozaf048.222
VL - 31
IS - 7
SP - 442
EP - 443
PB - Oxford Academic
AN - OPUS4-63804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Methodologies implemented to measure key properties of graphene and other 2D materials
N2 - The key properties and suitable measurement methods for the characterization of graphene-related 2D materials are presented. A case study will be discussed about the chemical characterisation of functionalised graphene used in inks along the production chain.
T2 - European-African Graphene Workshop
CY - Parys, South Africa
DA - 26.11.2025
KW - X-ray photoelectron spectroscoyp
KW - Raman spectroscopy
KW - Defects
KW - Surface Chemistry
PY - 2025
AN - OPUS4-64959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
T1 - Overview of ongoing research and future prospects on polyethylene neutron shielding materials at BAM
N2 - The extension of the interim storage period of radioactive waste before disposal will cause additional challenges for the nuclear waste management in Germany, so that an extensive knowledge of the long-term performance of casks, including their components and inventories, will be required for future extended storage licenses.
Ultra-high and high molecular weight polyethylenes ((U)HMW-PE) are used for neutron shielding purposes in casks for storage and transport of spent fuel and high-level waste due to their extremely high hydrogen content. During their service life of several decades as cask components, the PE materials are exposed to neutron and gamma radiation from the radioactive inventory of the casks, mechanical assembling stresses and temperature. All these combined effects affect the material properties of such components which in turn may be crucial for some possible accident scenarios.
At the Bundesanstalt für Materialforschung und -prüfung (BAM), the effects of high temperature exposure in combination with subsequent or previous irradiation were investigated with a comprehensive aging program including thermal aging at 125 °C for different aging periods up to 5 years and irradiation with doses ranging from 50 to 600 kGy.
This contribution provides an overview of the ongoing research related to the structural changes of (U)HMW-PE induced by gamma irradiation and high temperature exposure and focuses on current research perspectives at BAM with regard to the prediction of the dynamic behavior of the material during extended interim storage in case of an accident scenario. First results of the coupled effect of temperature, radiation and mechanical loading will be presented. The effect of microstructural changes induced by gamma irradiation and high temperature on the mechanical behavior of (U)HMW-PE will be assessed.
T2 - PATRAM22
CY - Juan-les-Pins, France
DA - 11.06.2023
KW - (U)HMWPE
KW - Ageing
KW - Irradiation
KW - WAXD
KW - SHPB
PY - 2023
AN - OPUS4-57708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - FAIR tensile test data in PMD: From a standard-compliant application ontology to RDF data in a triple store
N2 - Following the new paradigm of materials development, design and optimization, the digitalization of materials and processes is the main goal which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR (findability, accessibility, interoperability, reusability) principles are to be ensured. This includes storage, processing and querying of data in a preferably standardized form, also addressing the incorporation of standardization bodies. To meet the challenge to contextualize material data in a way that is consistent with all stakeholders, all necessary information on the condition of the material including production and application-related changes have to be made available via a uniform, machine-readable description. For this purpose, ontologies are to be used since they allow for machine-understandable knowledge representations and semantic conceptualizations that are needed for data management and the digitalization in the field of materials science.
With respect to this currently ever-growing topic of integration and reuse of data and knowledge from synthesis, production and characterization of materials, this presentation shows the efforts taken within the project Platform MaterialDigital (PMD, materialdigital.de) to store tensile test data in accordance with a standard-compliant ontological representation. The includes the path from developing an ontology in accordance with the respective standard, converting ordinary and arbitrarily selected data gained from standard tests into the interoperable RDF format, up to connecting the ontology and data, respectively. Finally, such data can be queried from a triple store.
In the field of material science and engineering (MSE), most mechanical test methods are standardized which serves as a valid basis for ontology development. Therefore, the well-known tensile test of metals at room temperature (DIN EN ISO standard 6892-1:2019-11) was selected to be considered as one of the first use cases in PMD. This consideration within the PMD features both, the ontological representation of such a tensile test in accordance with the standard as well as exemplary data generation. The semantic connection of the ontology and data leads to interoperability and an enhanced ability of querying.
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - S355 steel sheet
KW - Mechanical testing
KW - Tensile test
KW - Digitization
KW - Ontology
KW - Data structure
KW - Material digital
PY - 2022
AN - OPUS4-55882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison Report ISO/TC 229 Nanotechnology for ISO/TC 202 Microbeam Analysis and vice-versa
N2 - The liaison between the ISO technical committees TC 229 Nanotechnologies and TC 202 Microbeam analysis is described in detail with highlight on the projects under development and published since 2024 and which involve input /knowledge from ISO/TC 202.
T2 - 32nd Plenary Meeting of ISO/TC 202 Microbeam Analysis
CY - London, United Kingdom
DA - 28.10.2025
KW - Nanotechnology
KW - Microabeam analysis
KW - Standardisation
KW - ISO
PY - 2025
AN - OPUS4-64551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
A1 - Fontanges, Richard
T1 - A new deep-learning AI tool for analysing images of complex nanoparticles
N2 - A thousand times thinner than a human hair, nanoparticles (NPs) are finding applications in a range of modern products. However, as some can affect human health or the environment, knowing the types present is essential. Electron microscopy is the ‘gold standard’ for NP analysis, allowing identification based on manual size analysis, but a new method was required to analyse these particles quickly, accurately and in a consistent way.
KW - Nanoparticles
KW - Imaging
KW - AI tool
KW - Particle size and shape distribution
PY - 2024
UR - https://www.euramet.org/casestudies/casestudiesdetails/news/a-new-deep-learning-ai-tool-for-analysing-images-of-complex-nanoparticles
SP - 1
EP - 2
PB - EURAMET
CY - Braunschweig
AN - OPUS4-60095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ren, L.
A1 - Pollard, A.
A1 - Hodoroaba, Vasile-Dan
T1 - Measurement of Lateral Size of Graphene Oxide Flakes by SEM - An Update of the VAMAS TWA 41 Project P13
N2 - The progress of the VAMAS interlaboratory comparison Project P13 "Lateral size of graphene oxide flakes by SEM" within the Technical Working Area 41 "Graphene and Related 2D Materials" is presented. The challenges at sample preparation on substrates for accurate measurement and image analysis as well as two different image analysis approaches, containing exact guidance how to measure the main descriptors for the lateral size measurement of the imaged graphene oxide flakes with Scanning Electron Microscopy are described. The implementation of the results into the corresponding ISO technical specification AWI/TS 23879 is also discussed and planned, in relation with the AFM part.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 49th Steering Committee Meeting
CY - Rio de Janeiro, Brazil
DA - 23.09.2024
KW - VAMAS
KW - Graphene oxide
KW - SEM
KW - Lateral size
KW - Interlaboratory comparison
PY - 2024
UR - http://www.vamas.org/twa41/documents/2023_vamas_twa41_project13_GO_SEM.pdf
AN - OPUS4-61434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - SEM/EDS as THE Versatile and Powerful Tool for Micro and Nano Analysis
N2 - The basic principles of generation of electrons and X-rays and the operation of SEM/EDS instruments are presented. Examples, recent successes and challenges in the analysis of nano-structures are given. Multi-method analytical approaches with the focus on imaging the nanoscale are highlighted. Details on the sample preparation and persepective on the automated analysis (sample preparation, measurement, data analyis and storage) are given. Metrological aspects, standardisation, and reference materials are also emphasized by examples.
T2 - Training Course Metrological Determination of Micro and Nano Contaminants in Food
CY - Berne, Switzerland
DA - 05.09.2023
KW - SEM
KW - EDS
KW - Microanalysis
KW - Nanoanalysis
KW - Imaging
PY - 2023
UR - https://www.sem.admin.ch/metas/en/home/dl/kurs_uebersicht/micro_nano_contaminants_in_food.html
AN - OPUS4-58188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madbouly, Loay Akmal
T1 - Chemical Analysis of Functionalized Graphene along the Production Chain
N2 - Graphene has been commercialized for over a decade. It is usually used in the form of suspensions or inks. In this study, we analyze the starting material for commercial functionalized graphene (FG) solutions and inks as well as their starting material (FG powders) using X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), energy-dispersive X-Ray spectroscopy (EDX), time of flight secondary ion mass spectrometry (ToF-SIMS) and Auger electron spectroscopy (AES). Graphene was functionalized with fluorine, oxygen, ammonia, and carboxylic acid.
Our results suggest a significant effect of water and commercial resins on the presence as well as the morphological behavior of graphene and associated functionalized group. For example, XPS analysis shows some significant differences between the solutions and the starting materials (powders). These changes can be explained by the location of the functionalization at the outer most surface as indicated by Chemello et al.
T2 - European Conference on Applications of Surface and Interface Analysis (ECASIA 2024)
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Functionalized graphene
KW - Commercial graphene
KW - Graphene inks
PY - 2024
AN - OPUS4-60446
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kömmling, Anja
T1 - Aging of elastomer O-rings and PE neutron shielding materials for radioactive waste containers
N2 - Our institution BAM in Berlin, Germany is concerned with research and testing of materials in the context of safety in chemistry and technology. Our working group is involved in the licensing procedures of casks for radioactive waste. Besides, we’re doing research on aging and lifetime prediction of elastomer O-rings and investigate degradation and thermal expansion of PE neutron shielding materials.
T2 - Polymers in nuclear applications
CY - Online meeting
DA - 01.12.2021
KW - Rubber
KW - Polyethylene
KW - Thermal expansion
KW - Lifetime
KW - Degradation
PY - 2021
UR - https://energiforsk.se/media/30631/bam_material_aging_analysis.pdf
AN - OPUS4-54191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaunich, Matthias
A1 - Goral, Milan
A1 - Sagradov, Ilja
A1 - Wolff, Dietmar
A1 - Völzke, Holger
T1 - Aging investigations of metal seals used in containers for interim storage of spent fuel
N2 - For bolted casks for used fuel and high level waste the sealing system has an important impact of ensuring safe enclosure of the inventory The used metal seals show some changes over time which have been addressed for nearly 15 years in running experiments at BAM The observed changes are temperature de pendent and therefore it is expected that test s at higher temperature allow for an acceleration of the effects and ideally the proposal of an ageing model covering the expected time of use . Nevertheless, questions concerning the influence of the experimental approach on the results and effects taking place at the initial days of ageing remain. To address these a new project was launched to give a better understanding of the seal behavior.
T2 - PVP2024, Pressure Vessels & Piping Conference
CY - Bellevue, WA, USA
DA - 29.07.2024
KW - Metal seal
KW - Aging
KW - Interim storage
PY - 2024
SN - 978-0-7918-8851-3
SP - 1
EP - 4
PB - ASME
AN - OPUS4-61357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Reliable Chemical Characterization Protocols for Industrial Graphene-Related Materials
N2 - Since its isolation, graphene has received growing attention from academia and industry due to its unique properties. Promising opportunities for applications are discussed in different field like electronics and optoelectronics, detection, and sensing devices, biosystems or chemical and environmental corrosion inhibition. Here, functionalization with elements like oxygen, nitrogen or fluorine can broaden the application, for example in composite materials. However, lack of generally accepted operation procedures hinders the commercialization, the so-called “what is my material” barrier. Therefore, first efforts were done to develop common, reliable, and reproducible ways to characterize the morphological and chemical properties of the industrially produced material.
In this contribution, our efforts in the development of reliable chemical characterizations protocols for functionalized graphene are presented. An ISO standard for the chemical characterization of graphene-related (GRM) is under development with X-ray photoelectron spectroscopy (XPS) having a prominent role. With its information depth of around 10 nm, which is the similar length scale as the thickness of particles of 2D materials consisting of a few monolayers, XPS seems to be highly suitable for the quantitative analysis of (functionalized) GRM. Thereby, different sample preparation methods like pressing the powders onto adhesive tapes, into recesses, or into solid pellets result in inconsistencies in the quantification. Furthermore, different morphologies like stacks of graphene layers (left figure) or irregular particles (right figure) lead to different analysis results for the chemical composition.
For the validation of the quantification with XPS and the further development of standards an international interlaboratory comparison was initiated under the head of the “Versailles Project on Advanced Materials and Standards” (VAMAS). First results are reported showing the suitability of the protocols. Finally, the XPS results are compared with the elemental composition results obtained after quantification with energy-dispersive X-ray spectroscopy (EDS) as a fast analytical method which is usually combined with electron microscopy.
T2 - nanoSAFE 2023
CY - Grenoble, France
DA - 05.06.2023
KW - X-ray photoelectron spectroscopy
KW - Functionalized graphene
KW - Interlaboratory comparison
KW - VAMAS
PY - 2023
AN - OPUS4-57652
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Knigge, Xenia
T1 - Influence of Sterilization on the Surface of Nanoparticles Studied with XPS / HAXPES in Comparison to SEM / EDS
N2 - Nanosafety is becoming increasingly important as nanomaterials are widely used in industrial processes and consumer products. For nanotoxicity measurements prior sterilization of the samples is necessary, but as structure activity relationships are made with properties of pristine particles, the question arises, if the sterilization process has an impact on the physico-chemical properties of nanoparticles and thus on the biological behavior.
This question will be addressed in this talk. For this purpose, results from SEM and EDS measurements are combined with those of a novel lab-based HAXPES spectrometer in order to obtain a more complete picture. At the end, an influence of sterilization will be evident, which indicates a restructuring of the nanoparticles owing to sterilization.
T2 - Microscopy & Microanalysis 2022
CY - Online meeting
DA - 31.07.2022
KW - XPS
KW - HAXPES
KW - SEM
KW - EDS
KW - Nanoparticles
PY - 2022
AN - OPUS4-55353
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Energy-Dispersive X-Ray Spectrometry (EDS) on GR2Ms for Routine/Standardized Elemental Analysis
N2 - The elemental analysis of solid matter by means of the Energy-Dispersive X-Ray Spectrometry (EDS) is meanwhile posible as a quick (seconds!) and more and more accurate analysis via standardsless (instantaneous) quantification. The sensitivity & quantification accuracy for light elements (C, O,..) has significantly increased in the recent years. The availability via table-top SEMs with incorporated EDS is also enhanced.
Further, the EDS analysis at an SEM is well-standardized, see ISO/TC 202 Microbeam Analysis & VAMAS/ TWA 37 Quantitative Microstructural Analysis in good liaisonships with ISO/TC 229 Nanotechnologies.
It is demostrated that key parameters such as oxygen-to-carbon atomic-% ratio and impurities can be realibly measured, with XPS as a reference method. Various EDS spectrometers and analysis conditions are tested and the validity of the EDS quantification of an ionic liquid of well-defined chemical composition is demonstrated.
Next steps are: launch of a corresponding VAMAS interlaboratory comparison and discussions within ISO/TC 202 Microbeam Analysis.
T2 - 32nd Plenary Meeting of ISO/TC 202 Microbeam Analysis
CY - London, United Kingdom
DA - 28.10.2025
KW - GR2M
KW - EDS
KW - Quantification
KW - XPS
KW - Light elements
KW - 2D materials
PY - 2025
AN - OPUS4-64553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Chemical and topographical analyses of ps-laser generated HSFL on titanium alloy
N2 - Laser-induced periodic surface structures (LIPSS) enable a large variety of different surface functionalizations for applications in the fields of optics, fluidics, tribology, or medicine. Moreover, high spatial frequency LIPSS (HSFL) provide an appealing and straightforward way for the generation of surface nanostructures featuring spatial periods even below 100 nm – far beyond the optical diffraction limit. However, the imposed surface functionalities are usually caused by both, topographic and chemical surface alterations. For exploring these effects in detail, multi-method characterization was performed here for HSFL processed on Ti-6Al-4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ~1 ps pulse duration, 1 – 400 kHz pulse repetition rate) under different scan processing conditions. The subsequent sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), stylus profilometry (SP), as well as near-surface chemical analyses by X-ray photoelectron spectroscopy (XPS), hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results allow to qualify the laser ablation depth, the geometrical HSFL characteristics and provide detailed insights into the depth extent and the nature of the ps-laser-induced near-surface oxidation arising from the laser-processing in ambient air and into the relevance of heat-accumulation effects at high pulse repetition rates. Moreover, the direct comparison of the HAXPES and XPS data reveals the role of surface-covering organic contaminants adsorbed from the ambient atmosphere without ion-sputter depth profiling. Furthermore, reduction of the oxides by sputtering can be avoided.
T2 - SPIE Photonics Europe 2024 Conference, Symposium "Lasers and Photonics for Advanced Manufacturing"
CY - Strasbourg, France
DA - 07.04.2024
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrafast laser processing
KW - Nanostructures
KW - Chemical analyses
PY - 2024
UR - https://spie.org/photonics-europe/presentation/Chemical-and-topographical-analyses-of-ps-laser-generated-high-spatial/13005-69#_=_
AN - OPUS4-59853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Methodologies implemented to measure key properties of graphene and other 2D materials - EDX
N2 - The elemental analysis of solid matter by means of the Energy-Dispersive X-Ray Spectrometry (EDS) is meanwhile posible as a quick (seconds!) and more and more accurate analysis via standardsless (instantaneous) quantification. The sensitivity & quantification accuracy for light elements (C, O,..) has significantly increased in the recent years. The availability via table-top SEMs with incorporated EDS is also enhanced.
It is demostrated that key parameters such as oxygen-to-carbon atomic-% ratio and impurities can be realibly measured, with XPS as a reference method. Various EDS spectrometers and analysis conditions are tested and the validity of the EDS quantification of an ionic liquid of well-defined chemical composition is demonstrated.
T2 - Advanced Materials Graphene: The implementation of SbD and SSbD
CY - Parys, South Africa
DA - 26.11.2025
KW - Light elements
KW - EDS
KW - Quantification
KW - Oxygen-to-carbon ratio
KW - XPS
KW - Graphene-realted 2D materials
PY - 2025
AN - OPUS4-64943
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - STEM in SEM vs SE InLens type SEM as a Reliable Analytical Pair Tool for Measurement of Nanoparticle Size and Shape Distribution
N2 - In this lecture, following points are addressed:
– Advantages of correlative analysis in electron microscopy
– Measurement principle of the different electron microscopy modes used
– Presentation of the nanomaterials used for this study
– Role of sample preparation
– Sequence kV variation with InLens & transmission detection of the same field-of-view
– Conclusive remarks including Monte Carlo simulations
T2 - Microscopy and Microanalysis 2024
CY - Cleveland, OH, USA
DA - 28.07.2024
KW - Correlative analysis
KW - Electron microscopy
KW - Nanoparticles
KW - SEM
KW - STEM-in-SEM
KW - Particle size distribution
KW - Titanium dioxide
PY - 2024
AN - OPUS4-60804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Energy Dispersive X Ray Spectrometry (EDS) on GR2Ms for Routine/Standardized Elemental Analysis
N2 - The elemental analysis of solid matter by means of the Energy-Dispersive X-Ray Spectrometry (EDS) is meanwhile posible as a quick (seconds!) and more and more accurate analysis via standardsless (instantaneous) quantification. The sensitivity & quantification accuracy for light elements (C, O,..) has significantly increased in the recent years. The availability via table-top SEMs with incorporated EDS is also enhanced.
Further, the EDS analysis at an SEM is well-standardized, see ISO/TC 202 Microbeam Analysis & VAMAS/ TWA 37 Quantitative Microstructural Analysis in good liaisonships with ISO/TC 229 Nanotechnologies.
It is demostrated that key parameters such as oxygen-to-carbon atomic-% ratio and impurities can be realibly measured, with XPS as a reference method. Various EDS spectrometers and analysis conditions are tested and the validity of the EDS quantification of an ionic liquid of well-defined chemical composition is demonstrated.
Next steps are: launch of a corresponding VAMAS interlaboratory comparison and discussions within ISO/TC 202 Microbeam Analysis.
T2 - ISO/TC 229 Nanotechnologies Meeting Week
CY - Stockholm, Sweden
DA - 19.05.2025
KW - Graphene-related 2D materials (GR2M)
KW - Energy-Dispersive X-Ray Spectrometry (EDS)
KW - Elemental analysis
KW - Quantification
KW - ISO/TC 229 Nanotechnologies
PY - 2025
AN - OPUS4-63190
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS Regional Workshop in Germany
N2 - An overview on the VAMAS technical working areas (TWA) and projects where Germany is active has been given. The role of VAMAS as an international pre-standardisation platform, including its intense collaboration with international bodies ISO, CEN, OECD and CCQM and national organizations like DIN has been highlighted.
T2 - VAMAS Regional Workshop 2023 - What can pre-normative research do for industry?
CY - Online meeting
DA - 24.01.2023
KW - VAMAS
KW - Advanced materials
KW - Inter-laboratory comparisons
KW - Regional workshop
PY - 2023
UR - https://www.bam-akademie.de/kursangebot/kurs/vamas-regional-workshop-2023-23.html?lang=en
AN - OPUS4-57281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Report VAMAS/TWA 37 "Quantitative Microstructural Analysis" & Liaison with ISO/TC 202 "Microbeam Analysis"
N2 - The progress in activities on Quantitative MicroStructural Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 Microbeam Analysis is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing projects "Development of guidelines for reproducible TEM specimen preparation by FIB processing", "Measurement of dislocation density in metallic materials by Transmission Electron Microscope (TEM)", "Repeatability of high angular resolution electron backscatter diffraction (HR-EBSD) analysis for elastic strain measurements", "Measurement of grain size and distribution of nanocrystalline nickel by using Transmission Kikuchi Diffraction (TKD) in SEM" and the just started project "Evaluation Method of Surface Layer Quality of TEM Specimen Prepared by focused Ion Beam Processing" are presented in detail.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 50th Steering Committee Meeting
CY - London, United Kingdom
DA - 15.09.2025
KW - VAMAS
KW - Interlaboratory comparison
KW - Microbeam Analysis
KW - Electron Microscopy
KW - ISO/TC 202
KW - Sample preparation
PY - 2025
AN - OPUS4-64231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis
N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. The recently started project FIB sample processing for TEM is highlighted. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved. Planed regional VAMAS Workshops in Germany in 2023 are announced.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 47th Steering Committee Meeting
CY - Torino, Italy
DA - 18.10.2022
KW - VAMAS
KW - Microbeam analysis
KW - FIB
KW - TEM
KW - Sample preparation
KW - EBSD
PY - 2022
UR - https://amdgroup.inrim.it/events/vamas-sc-meeting-47
AN - OPUS4-56146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Terborg, R.
A1 - Kim, K. J.
A1 - Hodoroaba, Vasile-Dan
T1 - Determination of Thin Film Thickness and Composition using Energy Dispersive EPMA
N2 - The thickness of thin films can be measured by various methods, e.g., profilometry, ellipsometry, atomic force microscopy (AFM), or X-ray reflectometry. For the additional determination of thin film composition, techniques like X-ray photoelectron spectroscopy (XPS) or mass spectrometry-based techniques can be used. An alternative non-destructive technique is electron probe microanalysis (EPMA). This method assumes a sample of homogenous (bulk) chemical composition, so that it cannot be usually applied to thin film samples. However, in combination with the thin film software StrataGEM, the thickness as well as the composition of such films on a substrate can be determined.
This has been demonstrated for FeNi on Si and SiGe on Al2O3 film systems. For both systems five samples with different elemental composition and a reference were produced and characterised by Korean research institute KRISS using inductively coupled plasma mass spectrometry (ICP-MS), Rutherford backscattering (RBS), and transmission electron microscopy (TEM). These samples were used for an international round robin test.
In 2021, a new and open-source thin film evaluation programme called BadgerFilm has been released. It can also be used to determine thin film composition and thickness from intensity ratios of the unknown sample and standards (k-ratios).
In this contribution, we re-evaluated the data acquired for the FeNi and SiGe systems using the BadgerFilm software package and compared the resulting composition and thickness with the results of the established StrataGEM software and other reference methods. With the current evaluation, the BadgerFilm software shows good agreement with the composition and thickness calculated by StrataGEM and as the reference values provided by the KRISS.
KW - Thin films
KW - Elemental composition
KW - Film thickness
KW - EPMA (Electron Probe Microanalysis)
PY - 2022
DO - https://doi.org/10.1017/S143192762200318X
VL - 28
IS - Suppl. 1
SP - 672
EP - 673
PB - Cambridge University Press
AN - OPUS4-55437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Deep Insights into Functionalised Nanoparticles with Photoelectron Spectroscopy
N2 - Modern instrumentation X-ray photoelectron instrumentation combines soft and hard X-rays. Additonally, in the last years methods were developed for the analysis of the measurement data to elucidate the composition and thickness of coatings of nanoparticles. In this presentation four examples will be presented: quantum dots, silica-coated iron-oxide nanoparticles, mixed Fe-Ni-O nanoparticles and amine-functionalized silica nanoparticles. These different nanoparticles are used for displays, for biomedicine, for water splitting, and as additives and fillers.
T2 - United Kingdom Surface Analysis Forum Meeting 2025
CY - Teddington, UK
DA - 15.07.2025
KW - Simulation
KW - Oxygen evolution reaction
KW - Transmission electron microscopy
KW - Quantitative nuclear magnetic resonance (qNMR)
PY - 2025
AN - OPUS4-63733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - VAMAS Project A33: Chemical composition of functionalized graphene with X ray photoelectron spectroscopy (XPS)
N2 - The results of the interlaboratory comparison about the chemical composition of functionalized graphene are presented.
T2 - DIN Meeting NA 062-08-16 AA
CY - Berlin, Germany
DA - 25.05.2023
KW - X-ray photoelectron spectroscopy
KW - Functionalized graphene
KW - Interlaboratory comparison
KW - VAMAS
PY - 2023
AN - OPUS4-57650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Knigge, Xenia
T1 - Characterization of sterilized nanoparticles by lab-based XPS and HAXPES
N2 - The novel lab-based HAXPES spectrometer (ULVAC-PHI Quantes) gives us the possibility to measure XPS at 1486.6 eV (monochromatic Al Kα source) and HAXPES at 5414.9 eV (monochromatic Cr Kα source) on a sample at the same position. The surface analysis with this spectrometer leads to an information depth of about 10 nm for XPS and in comparison, to an analysis of deeper regions of about 30 nm for HAXPES measurements. This method provides a nondestructive way to distinguish between the near-surface region of the nanoparticles and the whole nanoparticle. Additionally, HAXPES gives access to deeper core levels at higher energy.
An application of this technique is presented using nanoparticles. The results shown were obtained with nanoparticles, that were treated differently by means of sterilization for nanosafety (i.e., before studying their toxicity it is important to establish whether nanomaterials are sterile and, if not, to be treated either via microwave or autoclave sterilisation). As a complementary method, the data is compared with SEM and EDX measurements. All methods demonstrate the influence of sterilization. More specifically, these results show that the sterilization step must be considered in the physical-chemical description of the particles for establishing reliable (quantitative structure-activity) relationships.
T2 - ECASIA 2022
CY - Limerick, Ireland
DA - 29.05.2022
KW - XPS
KW - HAXPES
KW - Nanoparticles
PY - 2022
AN - OPUS4-54968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Ce0.5Zr0.5O2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Ce0.5Zr0.5O2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Ce0.5Zr0.5O2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7965445
PB - Zenodo
CY - Geneva
AN - OPUS4-57670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Analysis of Nanoparticles
N2 - The determination of the thickness and composition of the coating is crucial for the understanding of the properties of nanoparticles. Four different approaches will be presented: (i) numerical methods, (ii) descriptive formulae, (iii) the simulation of spectra with Monte-Carlo methods, and (iv) inelastic background analysis. The advantages and limits of these methods will be discussed.
T2 - XPS Workshop
CY - Teddington, United Kingdom
DA - 14.07.2025
KW - Numerical simulation
KW - Emperical formulae
KW - Simulation
KW - Inelastic background analysis
PY - 2025
AN - OPUS4-63732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Correlating HR-TEM and XPS to elucidate the core-shell structure of ultrabright CdSE/CdS semiconductor quantum dots
N2 - Controlling the thickness and tightness of surface passivation shells is crucial for many applications of core-shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the application-relevant functionality like a high photoluminescence (PL) quantum yield. This calls for a whole nanoobject approach. Moreover, the thickness of the organic coating remains often unclear.
By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. The results of the different methods match very well within the different measurement uncertainties. Additionally, results obtained with energy-resolved XPS using excitation energies between 200 eV and 800 eV are discussed with respect to a potential core/shell intermixing.
Moreover, the future application potential of this approach correlating different sizing and structural methods is discussed considering the method-inherent uncertainties and other core/multi-shell nanostructures.
T2 - E-MRS Fall Meeting
CY - Online meeting
DA - 20.09.2021
KW - Core-shell nanoparticles
KW - Quantum dots
KW - High-resolution transmission electron microscopy
KW - X-ray Photoelectron Spectroscopy
PY - 2021
AN - OPUS4-53365
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of CeO2/Co3O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of CeO2/Co3O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Nanoparticles
KW - CeO2/Co3O4
PY - 2023
DO - https://doi.org/10.5281/zenodo.7989698
PB - Zenodo
CY - Geneva
AN - OPUS4-57760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of Fe3O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of Fe3O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Fe3O4
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7990085
PB - Zenodo
CY - Geneva
AN - OPUS4-57759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Interlaboratory comparisons for validated measurements of the surface chemistry of nanomaterials
N2 - Interlaboratory comparisons are essential tools for validating new protocols or methods. The properties of advanced materials are largely determined by surface chemistry. Using a VAMAS interlaboratory comparison on the surface functionalization of GR2DM, it is explained what insights can be gained from such a comparison.”
T2 - Nanomesure France Journee technique
CY - Paris, France
DA - 04.11.2025
KW - VAMAS
KW - Functionalized graphene
KW - X-ray photoelectron spectroscopy
PY - 2025
AN - OPUS4-65002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Abram, Sarah-Luise
A1 - Thünemann, Andreas
A1 - Rühle, Bastian
A1 - Radnik, Jörg
A1 - Bresch, Harald
A1 - Resch-Genger, Ute
A1 - Hodoroaba, Vasile-Dan
T1 - The Role of Electron Microscopy in the Development of Monodisperse Cubic Iron Oxide Nanoparticles as Certified Reference Material for Size and Shape
N2 - BAM is currently building up a platform of novel nanoRMs relying on iron oxide nanoparticles of different shape, size and surface chemistry. Iron oxide was chosen as a core material because of its relevance to the material and life sciences.
As a first candidate of this series, we present cubic iron oxide nanoparticles with a nominal edge length of 8 nm. These particles were synthesized by thermal decomposition of iron oleate in high boiling organic solvents adapting well-known literature procedures. After dilution to a concentration suitable for electron microscopy (TEM and SEM) as well as for small-angle X-ray scattering (SAXS) measurements, the candidate nanoRM was bottled and assessed for homogeneity and stability by both methods following the guidelines of ISO 17034 and ISO Guide 35.
The particle sizes obtained by both STEM-in-SEM and TEM are in excellent agreement with a minimum Feret of 8.3 nm ± 0.7 nm. The aspect ratio (AR) of the iron oxide cubes were extracted from the images as the ratio of minimum Feret to Feret resulting in an AR of 1.18 for TEM to 1.25 for SEM. Alternatively, a rectangular bounding box was fitted originating from the minimum Feret and the longest distance through the particle in perpendicular direction. This led to AR values of 1.05 for TEM and 1.12 for SEM, respectively. The results confirm the almost ideal cubic shape.
KW - Reference nanoparticles
KW - Iron oxide
KW - Cubical shape
KW - Electron microscopy
KW - SAXS
KW - Nano CRM
KW - Size
PY - 2022
DO - https://doi.org/10.1017/S1431927622003610
SN - 1435-8115
VL - 28
IS - Suppl. 1
SP - 802
EP - 805
PB - Cambridge University Press
AN - OPUS4-55599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Reliable measurements of the chemical composition of graphene-related 2D materials with X-ray photoelectron spectroscopy
N2 - Graphene and related 2D materials (GR2Ms) are now entering an exciting phase of commercialization and use in products. Graphene nanoplatelets (GNPs) can be obtained in rather large quantities, but the properties of these industrially produced powders can vary depending on the production method, and even from batch to batch. Understanding and optimizing the surface chemistry of GNPs, modified through chemical functionalization processes is crucial, because it affects their dispersibility in solvents and matrices for the purpose of embedding them into real-world products. Therefore, reliable and repeatable measurements of the surface chemistry of functionalized GNPs are an important issue for suppliers as well as users of these materials. To address these concerns, international documentary ISO standards for measurement methodologies are under development which incorporate protocols that are becoming widely accepted in the community.
Recently, it was shown that pelletizing led to lower average O/C atomic ratios than those measured for powders [1]. In another study, the influence of the morphology on the degree of functionalization was shown [2]. As expected, a higher degree of functionalization was detected for smaller GNPs. The functionalization was located at the outermost surfaces of the GNPs by comparing experiments using photoelectron with soft (Al Kα, 1.486 keV) and hard X-rays (Cr Kα, 5.405 keV). Therefore, it is important for those using GNPs to understand both the physical and chemical properties of these particles, when considering their use in different applications.
The next step for reliable characterization protocols was the realization of an interlaboratory comparison under the auspices of VAMAS (Versailles Project on Advanced Materials and Standards) with 22 participating laboratories from all over the world. Samples of oxygen-, nitrogen-, and fluorine- functionalized GNPs were provided to the participants along with a measurement protocol. Participants were asked to prepare the samples as powders on a tape, powders in a sample holder recess, or as pellets. The lower measured O/C ratio reported for pelletized samples [1] was confirmed. The lowest scattering of the results was observed for the powders measured in the recess (Fig. 1). Furthermore, an influence of the humidity on the results was observed.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Interlaboratory Comparison
KW - Functionalized graphene
KW - Sample preparation
PY - 2024
AN - OPUS4-60533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Rades, Steffi
A1 - Borghetti, P.
A1 - Ortel, Erik
A1 - Wirth, Thomas
A1 - Garcia, S.
A1 - Gómez, E.
A1 - Blanco, M.
A1 - Alberto, G.
A1 - Martra, G.
T1 - Organic surface modification and analysis of titania nanoparticles for self‐assembly in multiple layers
N2 - The characteristics of TiO2 coatings can greatly influence their final performance in large‐scale applications. In the present study, self‐assembly of TiO2 nanoparticles (NPs) in multiple layers was selected as a deposition procedure on various substrates. For this, the main prerequisite constitutes the surface modification of both NPs and substrate with, for example, silane coupling agents. A set of functionalized TiO2 NPs has been produced by reaction with either (3‐aminopropyl)triethoxysilane (APTES) or (3‐aminopropyl)phosphonic acid (APPA) to functionalize the NP surface with free amino‐groups. Then, the complementary functionalized NP set can be obtained from an aliquot of the first one, through the conversion of free surface amino groups to aldehydes by reaction with glutaraldehyde (GA). Several types of TiO2 NPs differing in size, shape, and specific surface area have been functionalized. Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), SEM/ energy‐dispersive X‐ray spectroscopy (EDS), XPS, Auger electron spectroscopy (AES), and Time‐of‐Flight (ToF)‐SIMS analyses have been carried out to evaluate the degree of functionalization, all the analytical methods employed demonstrating successful functionalization of TiO2 NP surface with APTES or APPA and GA.
KW - TiO2
KW - Nanoparticles
KW - Surface functionalization
KW - Layer-by-layer deposition
KW - Surface chemical analysis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508601
DO - https://doi.org/10.1002/sia.6842
SN - 1096-9918
VL - 52
IS - 12
SP - 829
EP - 834
PB - John Wiley & Sons Ltd
AN - OPUS4-50860
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Role of Sample Preparation for Accurate and Automated Morphological Analysis of Nanoparticles proven in Interlaboratory Comparison Exercises
N2 - Traceable morphological and chemical characterization of nanomaterials with respect to the various possible sizes, size distributions, shapes, and concentrations of real-world nanoparticles (NPs) is a challenging task. Particularly for the nonspherical, non-monodisperse nanoparticles – as typically for most of the commercial particles, including their strong tendency to agglomerate, there is a lack of standard operation procedures providing accurate nanoparticle characterisation.
In the framework of the pre-standardisation framework of VAMAS (Versailles Project on Advanced Materials and Standards, www.vamas.org) two interlaboratory comparison (ILC) studies are being carried out under the Technical Working Area (TWA) 34 “Nanoparticle Populations”:i) Project #15 addresses the analysis of the size and shape distribution of TiO2 bipyramidal NPs by traceable imaging methods such as TEM, SEM, STEM-in-SEM, AFM as well as with SAXS as an ensemble method. This ILC is thought as the next level development of the case studies exemplified in the published ISO standards ISO 21363 and ISO 19749. It was agreed to complete the first ILC with the NPs already prepared according to the same procedure on a TEM grid, and, at a later stage, to carry out second ILCs with the same NPs distributed to the participants as liquid suspensions together with protocols for the uniform NP deposition on suited substrates - as developed and optimized within the European project nPSize. Once having good deposition protocols available, the door for automated image analysis gets opened. Corresponding image analysis protocols and reporting templates have been distributed to the ILC participants, too.
ii) Project #16: two spherical SiO2 NP samples with bi-modal size distributions in two nominal relative number concentrations were prepared and distributed also as liquid suspensions accompanied by sample preparation, measurement, and image analysis protocols and reporting templates. Here, the NP concentration is the primary parameter to be measured. For the imaging methods it is targeted to
measure the relative nanoparticle concentrations (relative populations of the two modes).
The results of all the participating laboratories, in both ILCs, compiled in comparative representations will be shown and discussed for the first time. The reduction of the measurement uncertainties associated to the size, shape and number-concentration results induced by the significant improvement of the sample preparation on substrates (as single particles with a high-density coverage), combined with welldefined image analysis procedures will be highlighted.
T2 - MaterialsWeek 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Nanoparticles
KW - VAMAS
KW - Interlaboratory comparison
KW - Sample preparation
KW - Nanoparticle concentration
PY - 2024
AN - OPUS4-60453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - The Role of Electron Microscopy in the Development of Monodisperse Cubic Iron Oxide Nanoparticles as CRM for Size and Shape
N2 - Due to their unique physico-chemical properties, nanoparticles are well established in research and industrial applications. A reliable characterization of their size, shape, and size distribution is not only mandatory to fully understand and exploit their potential and develop reproducible syntheses, but also to manage environmental and health risks related to their exposure and for regulatory requirements. To validate and standardize methods for the accurate and reliable particle size determination nanoscale reference materials (nanoRMs) are necessary. However, there is only a very small number of nanoRMs for particle size offered by key distributors such as the National Institute of Standards and Technology (NIST) and the Joint Research Centre (JRC) and, moreover, few provide certified values. In addition, these materials are currently restricted to polymers, silica, titanium dioxide, gold and silver, which have a spherical shape except for titania nanorods. To expand this list with other relevant nanomaterials of different shapes and elemental composition, that can be used for more than one sizing technique, we are currently building up a platform of novel nanoRMs relying on iron oxide nanoparticles of different shape, size and surface chemistry. Iron oxide was chosen as a core material because of its relevance for the material and life sciences.
T2 - Microscopy and Microanalysis 2022
CY - Online meeting
DA - 31.07.2022
KW - Certified Referencematerial
KW - Cubical Iron Oxide
KW - Nanoparticles
KW - Electron Microscopy
KW - Small-Angle X-ray Scattering
PY - 2022
AN - OPUS4-57035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cant, D. J. H.
A1 - Minelli, C.
A1 - Sparnacci, K.
A1 - Müller, Anja
A1 - Kalbe, H.
A1 - Stoger-Pollach, M.
A1 - Unger, Wolfgang
A1 - Werner, W. S. M.
A1 - Shard, A. G.
T1 - Surface-Energy Control and Characterization of Nanoparticle Coatings
N2 - Accurate and reproducible measurement of the structure and properties of high-value nanoparticles is extremely important for their commercialization. A significant proportion of engineered nanoparticle systems consist of some form of nominally core-shell structure, whether by design or unintentionally. Often, these do not form an ideal core-shell structure, with typical deviations including polydispersity of the core or shell, uneven or incomplete shells, noncentral cores, and others. Such systems may be created with or without intent, and in either case an understanding of the conditions for formation of such particles is desirable. Precise determination of the structure, composition, size, and shell thickness of such particles can prove challenging without the use of a suitable range of characterization techniques. Here, the authors present two such polymer core-shell nanoparticle systems, consisting of polytetrafluoroethylene cores coated with a range of thicknesses of either polymethylmethacrylate or polystyrene. By consideration of surface energy, it is shown that these particles are expected to possess distinctly differing coating structures, with the polystyrene coating being incomplete. A comprehensive characterization of these systems is demonstrated, using a selection of complementary techniques including scanning electron microscopy, scanning transmission electron microscopy, thermogravimetric analysis, dynamic light scattering, differential centrifugal sedimentation, and X-ray photoelectron spectroscopy. By combining the results provided by these techniques, it is possible to achieve superior characterization and understanding of the particle structure than could be obtained by considering results separately.
KW - Nanoparticles
KW - Core-shell
KW - XPS
KW - Size
KW - Thickness
KW - Damage
PY - 2020
DO - https://doi.org/10.1021/acs.jpcc.0c02161
VL - 124
IS - 20
SP - 11200
EP - 11211
PB - ACS
CY - Washington DC
AN - OPUS4-50899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Goral, Milan
A1 - Wolff, Dietmar
T1 - Insights for lifetime predictions of O-ring seals from five-year long-term aging tests
N2 - O-rings made of HNBR, EPDM and FKM were aged in the compressed and uncompressed state at 150 °C, 125 °C, 100 °C, 75 °C, 60 °C and 23 °C for aging times of up to five years. Hardness was measured and increased with aging time and temperature for HNBR and EPDM, but it remained practically constant for FKM. Indenter modulus measurements were performed on the lateral O-ring surface (that was free of DLO effects) to assess an influence of the compression during aging, but none was detected. The equilibrium compression set (CS) exhibited faster and stronger degradation than hardness and was used for lifetime predictions using the time-temperature superposition (TTS) principle. With an end-of-lifetime criterion of 70 % CS, lifetimes of 4.5 years, 50 years and 526 years at 75 °C were estimated for HNBR, EPDM and FKM, respectively. The activation energies derived from an Arrhenius plot of the shift factors from the TTS were 85 kJ/mol, 99 kJ/mol and 78 kJ/mol for HNBR, EPDM and FKM, respectively, revealing that a higher activation energy does not necessarily mean that the material has a higher lifetime at lower temperatures. Furthermore, the measured lifetime of EPDM O-rings at 100 °C (5 years) was compared to that predicted on the basis of the lifetime at 150 °C as well as 125 °C using the corresponding shift factors. The error of the prediction was only ± 4 %. However, this precise prediction could only be achieved using the five-year long-term aging data. When using only data from aging times up to 0.5 years and 2 years, the lifetime of EPDM O-rings at 100 °C was underestimated by 31 % and 22 %, respectively.
KW - HNBR
KW - EPDM
KW - FKM
KW - DLO
KW - Hardness
KW - Compression set
KW - Rubber
KW - Elastomer
KW - Degradation
PY - 2020
DO - https://doi.org/10.1016/j.polymdegradstab.2020.109278
VL - 179
SP - 109278
PB - Elsevier Ltd.
AN - OPUS4-51060
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Analysis of Particle Size Distribution for Bimodal Model Nanoparticles by Scanning Electron Microscopy
N2 - The present study addresses the capability of measurement of relative particle number concentration by scanning electron microscopy for model bimodal silica and gold samples prepared in the frame of the European research project “nPSize - Improved traceability chain of nanoparticle size measurements” as candidate reference nanoparticles.
T2 - Microscopy and Microanalysis 2020
CY - Online meeting
DA - 03.08.2020
KW - Nanoparticles
KW - Silica
KW - Gold
KW - Electron microscopy
KW - Particle size distribution
PY - 2020
AN - OPUS4-51112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing
N2 - To improve the predictive capability of long-term stress relaxation of elastomers during thermo-oxidative ageing, a method to separate reversible and irreversible processes was adopted.
The separation is performed through the analysis of compression set after tempering. On the Basis of this separation, a numerical model for long-term stress relaxation during homogeneous ageing is proposed. The model consists of an additive contribution of physical and chemical relaxation.
Computer simulations of compression stress relaxation were performed for long ageing times and the results were validated with the Arrhenius treatment, the kinetic study and the time-temperature superposition technique based on experimental data. For chemical relaxation, two decay functions are introduced each with an activation energy and a degradative process. The first process with the lower activation energy dominates at lower ageing times, while the second one with the higher activation energy at longer ageing times. A degradation-rate based model for the evolution of each process and ist contribution to the total system during homogeneous ageing is proposed. The main advantage of the model is the possibility to quickly validate the interpolation at lower temperatures within the range of slower chemical processes without forcing a straight-line extrapolation.
KW - Kinetic study
KW - Arrhenius
KW - TTS
KW - Modeling
KW - Chemical processes
KW - Stress relaxation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512931
DO - https://doi.org/10.3390/polym12092152
SN - 2073-4360
VL - 12
IS - 9
SP - 1
EP - 21
AN - OPUS4-51293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Goral, Milan
A1 - Kömmling, Anja
A1 - Probst, Ulrich
A1 - Wossidlo, Peter
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
A1 - Völzke, Holger
T1 - Langzeitversuche über 10 Jahre an Federkern-Metalldichtungen mit Aluminium- bzw. Silberummantelungen
N2 - Federunterstützte Metalldichtungen mit Aluminium(Al)- oder Silber(Ag)-Ummantelung werden u.a. in Behältern für Wärme entwickelnde radioaktive Abfälle eingesetzt, da diese Dichtungen eine sehr gute Dichtheit gewährleisten sowie Langlebigkeit und Beständigkeit gegenüber erhöhten Temperaturen und radioaktiver Strahlung aufweisen. Auch wenn die Sicherheit solcher Behälter und der verwendeten Dichtungen vielfach belegt wurde, sind sie Gegenstand andauernder Forschung, etwa im Hinblick auf eine absehbar benötigte verlängerte Zwischenlagerdauer. Aus diesem Grund werden an der Bundesanstalt für Materialforschung und -prüfung (BAM) im Fachbereich 3.4 „Sicherheit von Lagerbehältern“ seit über 20 Jahren Versuche an solchen Metalldichtungen durchgeführt. Dabei sollen zusätzliche Erkenntnisse hinsichtlich der Sicherheitsreserven der Dichtungen in unterstellten Störfallszenarien (axiale Bewegung des Deckelsystems bzw. Aufweitung der Nutgeometrie) und insbesondere detailliertere Erkenntnisse zum Langzeitverhalten gewonnen werden.
KW - Federunterstützte Metalldichtungen
KW - Transport- und Lagerbehälter für radioaktive Stoffe
KW - Langzeitversuche
KW - Alterung
KW - Dichtheit
KW - Leckagerate
KW - Helium-Dichtheitsprüfung
PY - 2023
VL - 2023
SP - 43
EP - 63
PB - ISGATEC GmbH
CY - Mannheim
AN - OPUS4-56399
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, R.
A1 - Elbers, I.
A1 - Undas, A.
A1 - Sijtsma, E.
A1 - Briffa, S.
A1 - Carnell-Morris, P.
A1 - Siupa, A.
A1 - Yoon, T.-H.
A1 - Burr, L.
A1 - Schmid, D.
A1 - Tentschert, J.
A1 - Hachenberger, Y.
A1 - Jungnickel, H.
A1 - Luch, A.
A1 - Meier, F.
A1 - Kocic, J.
A1 - Kim, J.
A1 - Park, B. C.
A1 - Hardy, B.
A1 - Johnston, C.
A1 - Jurkschat, K.
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Lynch, I.
A1 - Valsami-Jones, E.
T1 - Benchmarking the ACEnano toolbox for characterisation of nanoparticle size and concentration by interlaboratory comparisons
N2 - ACEnano is an EU-funded project which aims at developing, optimising and validating methods for the detection and characterisation of nanomaterials (NMs) in increasingly complex matrices to improve confidence in the results and support their use in regulation. Within this project, several interlaboratory comparisons (ILCs) for the determination of particle size and concentration have been organised to benchmark existing analytical methods. In this paper the results of a number of these ILCs for the characterisation of NMs are presented and discussed. The results of the analyses of pristine well-defined particles such as 60 nm Au NMs in a simple aqueous suspension showed that laboratories are well capable of determining the sizes of these particles. The analysis of particles in complex matrices or formulations such as consumer products resulted in larger variations in particle sizes within technologies and clear differences in capability between techniques. Sunscreen lotion sample analysis by laboratories using spICP-MS and TEM/SEM identified and confirmed the TiO2 particles as being nanoscale and compliant with the EU definition of an NM for regulatory purposes. In a toothpaste sample orthogonal results by PTA, spICP-MS and TEM/SEM agreed and stated the TiO2 particles as not fitting the EU definition of an NM. In general, from the results of these ILCs we conclude that laboratories are well capable of determining particle sizes of NM, even in fairly complex formulations.
KW - Nanomaterials
KW - Benchmarking
KW - Inter-laboratory comparison
KW - ACEnano
KW - Characterisation
KW - Size
KW - Concentration
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531852
DO - https://doi.org/10.3390/molecules26175315
SN - 1420-3049
VL - 26
IS - 17
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-53185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cosimi, Andrea
A1 - Stöbener, Daniel D.
A1 - Nickl, Philip
A1 - Schusterbauer, Robert
A1 - Donskyi, Ievgen
A1 - Weinhart, Marie
T1 - Interfacial nanoengineering of hydrogel surfaces via block copolymer self-assembly
N2 - Synthetic polymer hydrogels are valuable matrices for biotransformations, drug delivery, and soft implants. While the bulk properties of hydrogels depend on chemical composition and network structure, the critical role of interfacial features is often underestimated. This work presents a nanoscale modification of the gel−water interface using polymer brushes via a straightforward “grafting-to” strategy, offering an alternative to more cumbersome “grafting-from” approaches. Functional block copolymers with photoreactive anchor blocks are successfully self-assembled and UV-immobilized on hydrogel substrates despite their low solid content (<30 wt %). This versatile technique works on both bulk- and surface-immobilized hydrogels, demonstrated on poly(hydroxypropyl acrylate), poly(N-isopropylacrylamide), and alginate gels, allowing precise control over grafting density. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry revealed a homogeneous bilayered architecture. By “brushing-up”, the hydrogels’ interface can be tailored to enhance protein adsorption, improve cell adhesion, or impair the diffusive uptake of small molecules into the bulk gels. This effective interfacial nanoengineering method is broadly applicable for enhancing hydrogel performance across a wide range of applications.
KW - Brushing-up
KW - Benzophenone
KW - LCTS-type polymer
KW - Poly(glycidyl ether) (PGE)
KW - Fibroblast adhesion
KW - XPS
KW - ToF-SIMS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652966
DO - https://doi.org/10.1021/acsami.4c18632
SN - 1944-8244
VL - 17
IS - 6
SP - 10073
EP - 10086
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-65296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Sparnacci, K.
A1 - Unger, Wolfgang
A1 - Tougaard, S.
T1 - Determining nonuniformities of core-shell nanoparticle coatings by analysis of the inelastic background of X-ray photoelectron spectroscopy survey spectra
N2 - Most real core-shell nanoparticle (CSNP) samples deviate from an ideal core-shell structure potentially having significant impact on the particle properties. An ideal structure displays a spherical core fully encapsulated by a shell of homogeneous thickness, and all particles in the sample exhibit the same shell thickness. Therefore,
analytical techniques are required that can identify and characterize such deviations.
This study demonstrates that by analysis of the inelastic background in X-ray photoelectron spectroscopy (XPS) survey spectra, the following types of deviations can be identified and quantified: the nonuniformity of the shell thickness within a nanoparticle sample and the incomplete encapsulation of the cores by the shell material. Furthermore, CSNP shell thicknesses and relative coverages can be obtained. These results allow for a quick and straightforward comparison between several batches of a specific CSNP, different coating approaches, and so forth. The presented XPS methodology requires a submonolayer distribution of CSNPs on a substrate.
Poly(tetrafluoroethylene)-poly(methyl methacrylate) and poly(tetrafluoroethylene)-polystyrene polymer CSNPs serve as model systems to demonstrate the applicability of the approach.
KW - Core-shell
KW - Nanoparticles
KW - Inelastic background
KW - Polymers
KW - QUASES
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511315
DO - https://doi.org/10.1002/sia.6865
SN - 0142-2421
SN - 1096-9918
VL - 52
SP - 1
EP - 8
PB - Wiley
CY - Chichester
AN - OPUS4-51131
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - Residual stress in simple and complex geometries manufactured by laser powder bed fusion
N2 - Design of freedom, performance improvement, cost reduction and lead time reduction are key targets when manufacturing parts in a layer-by-layer fashion using the laser powder bed fusion process (LPBF). Many research groups are focussed on improving the LPBF process to achieve the manufacturing of sound parts from a structural integrity perspective. In particular, the formation and distribution of residual stress (RS) remains a critical aspect of LPBF. The determination of the RS in LPBF benefits from the use of neutron diffraction (ND), as it allows the non-destructive mapping of the triaxial RS with a good spatial resolution. Two case studies are presented based on experiments carried out on the angular-dispersive neutron diffractometers Strain Analyser for Large Scale Engineering Applications (SALSA) (Institut Laue Langevin, Grenoble) and STRESS-Spec (FRM II, Garching). The RS in LPBF parts having a rectangular and more complex geometry (lattice structure) is analysed. The former example discusses the mapping of the RS in a rectangular body manufactured from stainless steel 316L. The manufacturing of these parts was monitored using an in-situ thermography set-up to link the RS to the thermal history. The latter discusses the RS in a lattice structure manufactured from the nickel base superalloy IN625. This geometry is challenging to characterise, and the use of a X-ray computed tomography twin is presented as tool to support the alignment of the ND experiment. The results from these case studies show a clear link between the thermal history and the RS magnitudes, as well as giving insights on the RS formation.
T2 - 1st International Conference on Advanced Manufacturing for Air, Space and Land Transportation
CY - Online meeting
DA - 07.03.2022
KW - AGIL
KW - Residual Stress
KW - X-ray and Neutron Diffraction
KW - Additive Manufacturing
PY - 2022
AN - OPUS4-54449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L
N2 - Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.
T2 - MLZ User Meeting 2020
CY - Online meeting
DA - 08.12.2020
KW - Computed tomography
KW - Neutron diffraction
KW - X-ray diffraction
KW - Additive manufacturing
KW - Residual stress
KW - Thermography
KW - LPBF
KW - Laser Powder Bed Fusion
PY - 2020
AN - OPUS4-51793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D
A1 - Koptyug, A.
A1 - Manabaev, K.
A1 - Léonard, Fabien
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
A1 - Cheneler, D.
A1 - Loza, K.
A1 - Epple, M.
A1 - Surmenev, R.
A1 - Surmeneva, M.
T1 - The impact of post manufacturing treatment of functionally graded Ti6Al4V scaffolds on their surface morphology and mechanical strength
N2 - An ultrasonic vibration post-treatment procedure was suggested for additively manufac-tured lattices. The aim of the present research was to investigate mechanical properties andthe differences in mechanical behavior and fracture modes of Ti6Al4V scaffolds treated withtraditional powder recovery system (PRS) and ultrasound vibration (USV). Scanning electronmicroscopy (SEM) was used to investigate the strut surface and the fracture surface mor-phology. X-ray computed tomography (CT) was employed to evaluate the inner structure,strut dimensions, pore size, as well as the surface morphology of additively manufacturedporous scaffolds. Uniaxial compression tests were conducted to obtain elastic modulus,compressive ultimate strength and yield stress. Finite element analysis was performedfor a body-centered cubic (BCC) element-based model and for CT-based reconstructiondata, as well as for a two-zone scaffold model to evaluate stress distribution during elasticdeformation. The scaffold with PRS post treatment displayed ductile behavior, while USVtreated scaffold displayed fragile behavior. Double barrel formation of PRS treated scaffoldwas observed during deformation. Finite element analysis for the CT-based reconstructionrevealed the strong impact of surface morphology on the stress distribution in comparisonwith BCC cell model because of partially molten metal particles on the surface of struts,which usually remain unstressed.
KW - Additive manufacturing
KW - Electron beam melting
KW - Computed tomography
KW - FEM
KW - Lattice structures
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505960
DO - https://doi.org/10.1016/j.jmrt.2019.12.019
SN - 2238-7854
VL - 9
IS - 2
SP - 1866
EP - 1881
PB - Elsevier B.V.
AN - OPUS4-50596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artzt, K.
A1 - Mishurova, Tatiana
A1 - Bauer, P.-P.
A1 - Gussone, J.
A1 - Barriobero-Vila, P.
A1 - Evsevleev, Sergei
A1 - Bruno, Giovanni
A1 - Requena, G.
A1 - Haubrich, J.
T1 - Pandora’s Box–Influence of Contour Parameters on Roughness and Subsurface Residual Stresses in Laser Powder Bed Fusion of Ti-6Al-4V
N2 - The contour scan strategies in laser powder bed fusion (LPBF) of Ti-6Al-4V were studied at the coupon level. These scan strategies determined the surface qualities and subsurface residual stresses. The correlations to these properties were identified for an optimization of the LPBF processing. The surface roughness and the residual stresses in build direction were linked: combining high laser power and high scan velocities with at least two contour lines substantially reduced the surface roughness, expressed by the arithmetic mean height, from values as high as 30 μm to 13 μm, while the residual stresses rose from ~340 to about 800 MPa. At this stress level, manufactured rocket fuel injector components evidenced macroscopic cracking. A scan strategy completing the contour region at 100 W and 1050 mm/s is recommended as a compromise between residual stresses (625 MPa) and surface quality (14.2 μm). The LPBF builds were monitored with an in-line twin-photodiode-based melt pool monitoring (MPM) system, which revealed a correlation between the intensity quotient I2/I1, the surface roughness, and the residual stresses. Thus, this MPM system can provide a predictive estimate of the surface quality of the samples and resulting residual stresses in the material generated during LPBF.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Contour scan strategy
KW - Surface roughness
KW - Melt pool monitoring
KW - Residual stress
KW - Synchrotron X-ray diffraction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510585
DO - https://doi.org/10.3390/ma13153348
VL - 13
IS - 15
SP - 3348
AN - OPUS4-51058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Sydow, B.
A1 - Thiede, Tobias
A1 - Sizova, I.
A1 - Ulbricht, Alexander
A1 - Bambach, M.
A1 - Bruno, Giovanni
T1 - Residual Stress and Microstructure of a Ti-6Al-4V Wire Arc Additive Manufacturing Hybrid Demonstrator
N2 - Wire Arc Additive Manufacturing (WAAM) features high deposition rates and, thus, allows production of large components that are relevant for aerospace applications. However, a lot of aerospace parts are currently produced by forging or machining alone to ensure fast production and to obtain good mechanical properties; the use of these conventional process routes causes high tooling and material costs. A hybrid approach (a combination of forging and WAAM) allows making production more efficient. In this fashion, further structural or functional features can be built in any direction without using additional tools for every part. By using a combination of forging basic geometries with one tool set and adding the functional features by means of WAAM, the tool costs and material waste can be reduced compared to either completely forged or machined parts. One of the factors influencing the structural integrity of additively manufactured parts are (high) residual stresses, generated during the build process. In this study, the triaxial residual stress profiles in a hybrid WAAM part are reported, as determined by neutron diffraction. The analysis is complemented by microstructural investigations, showing a gradient of microstructure (shape and size of grains) along the part height. The highest residual stresses were found in the transition Zone (between WAAM and forged part). The total stress range showed to be lower than expected for WAAM components. This could be explained by the thermal history of the component.
KW - Additive manufacturing
KW - Neutron diffraction
KW - Residual stress
KW - Hybrid manufacturing
KW - WAAM
KW - Ti-6Al-4V
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508245
DO - https://doi.org/10.3390/met10060701
VL - 10
IS - 6
SP - 701
PB - MDPI
AN - OPUS4-50824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Schneider, J.
A1 - Kupsch, Andreas
A1 - Bruno, Giovanni
T1 - Using SXRR to Probe the Nature of Discontinuities in SLM Additive Manufactured Inconel 718 Specimens
N2 - The utilization of additive manufacturing (AM) to fabricate robust structural components relies on understanding the nature of internal anomalies or discontinuities, which can compromise the structural integrity. While some discontinuities in AM microstructures stem from similar mechanisms as observed in more traditional processes such as casting, others are unique to the AM process. Discontinuities in AM are challenging to detect, due to their submicron size and orientation dependency. Toward the goal of improving structural integrity, minimizing discontinuities in an AM build requires an understanding of the mechanisms of formation to mitigate their occurrence. This study utilizes various techniques to evaluate the shape, size, nature and distribution of discontinuities in AM Inconel 718, in a non-hot isostatic pressed (HIPed) as-built, non-HIPed and direct age, and HIPed with two step age samples. Non-destructive synchrotron radiation refraction and transmission radiography (SXRR) provides additional information beyond that obtained with destructive optical microscopy. SXRR was able to distinguish between voids, cracks and lack of melt in, due to its sensitivity to the orientation of the discontinuity.
KW - Additive manufacturing
KW - X-ray refraction radiography
KW - INCONEL 718
KW - Selective laser melting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509836
DO - https://doi.org/10.1007/s11661-020-05847-5
SN - 1543-1940
VL - 51
IS - 8
SP - 4146
EP - 4157
PB - Springer
AN - OPUS4-50983
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Artzt, K.
A1 - Haubrich, J.
A1 - Evsevleev, Sergei
A1 - Evans, Alexander
A1 - Meixner, M.
A1 - Serrano-Munoz, Itziar
A1 - Sevostianov, I.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Connecting Diffraction-Based Strain with Macroscopic Stresses in Laser Powder Bed Fused Ti-6Al-4V
N2 - The laser powder bed fusion (LPBF) production process often results in large residual stress (RS) in the parts. Nondestructive techniques to determine RS are badly needed. However, a reliable quantification of macro-RS (i.e., stress at the component level) by means of diffraction-based techniques is still a great challenge, because the link between diffraction-based strain and macro-RS is not trivial. In this study, we experimentally determine (by means of in-situ synchrotron radiation diffraction) this link for LPBF Ti-6Al-4V. We compare our results with commonly used models to determine the so-called diffraction elastic constants (DECs). We show that LPBF materials possess different DECs than wrought alloys, simply because their microstructural and mechanical properties are different. We also show that the existing models can be used to calculate DECs only if high accuracy of the RS values is not required. If the peculiarities of the microstructure have to be taken into account (as is the case of additively manufactured materials), a radically new approach is desirable.
KW - Tiatanium
KW - Synchrotron X-ray diffraction
KW - Macroscopic stress
KW - Laser powder bed fusion
KW - Texture
KW - Diffraction elastic constants
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506483
DO - https://doi.org/10.1007/s11661-020-05711-6
VL - 51
IS - 6
SP - 3194
EP - 3204
PB - Springer
AN - OPUS4-50648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evsevleev, Sergei
A1 - Sevostianov, I.
A1 - Mishurova, Tatiana
A1 - Hofmann, M.
A1 - Garcés, G.
A1 - Bruno, Giovanni
T1 - Explaining Deviatoric Residual Stresses in Aluminum Matrix Composites with Complex Microstructure
N2 - The residual stresses in multiphase metal Matrix composites with both random planar-oriented short fibers and particles were studied by neutron diffraction and by a model based on the reformulation of classic Maxwell’s homogenization method. Contrary to common understanding and state-of-the-art models, we experimentally observed that randomly oriented phases possess non-hydrostatic residual stress. The recently developed modeling Approach allows calculating the residual stress in all phases of the composites. It rationalizes the presence of deviatoric stresses Accounting for the interaction of random oriented phases with fibers having preferential orientation.
KW - Metal matrix composite
KW - Residual stress
KW - Deviatoric
KW - Micromechanics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506472
DO - https://doi.org/10.1007/s11661-020-05697-1
VL - 51
IS - 6
SP - 3104
EP - 3113
PB - Springer
AN - OPUS4-50647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Mishurova, Tatiana
A1 - Thiede, Tobias
A1 - Sprengel, Maximilian
A1 - Kromm, Arne
A1 - Nadammal, Naresh
A1 - Nolze, Gert
A1 - Saliwan Neumann, Romeo
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - The residual stress in as‑built Laser Powder Bed Fusion IN718 alloy as a consequence of the scanning strategy induced microstructure
N2 - The effect of two types of scanning strategies on the grain structure and build-up of Residual Stress (RS) has been investigated in an as-built IN718 alloy produced by Laser Powder Bed Fusion (LPBF). The RS state has been investigated by X-ray diffraction techniques. The microstructural characterization was performed principally by Electron Backscatter Diffraction (EBSD), where the application of a post-measurement refinement technique enables small misorientations (< 2°) to be resolved. Kernel average misorientation (KAM) distributions indicate that preferably oriented columnar grains contain higher levels of misorientation, when compared to elongated grains with lower texture. The KAM distributions combined with X-ray diffraction stress maps infer that the increased misorientation is induced via plastic deformation driven by the thermal stresses, acting to self-relieve stress. The possibility of obtaining lower RS states in the build direction as a consequence of the influence of the microstructure should be considered when envisaging scanning strategies aimed at the mitigation of RS.
KW - Additive manufacturing
KW - LPBF
KW - Residual stress
KW - Inconel 718
KW - Kernel average misorientation
KW - Texture
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511769
DO - https://doi.org/10.1038/s41598-020-71112-9
VL - 10
IS - 1
SP - 14645
AN - OPUS4-51176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - ToF-SIMS at advanced materials - from nano to energy
N2 - The basic principles of ToF-SIMS will be explained. Examples of the use of ToF-SIMS for the investigation of titania and core-shell nanoplastic will be given. Furhtermore, 3d reconstruction is explained for nanoparticle research and energy-related materials.
T2 - BUA Summer School Mass Spectrometry
CY - Berlin, Germany
DA - 04.10.2022
KW - ToF-SIMS
KW - Nanomaterials
KW - Imaging
PY - 2022
AN - OPUS4-55897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nickl, Philip
A1 - Radnik, Jörg
A1 - Azab, W.
A1 - Donskyi, Ievgen
T1 - Surface characterization of covalently functionalized carbon-based nanomaterials using comprehensive XP and NEXAFS spectroscopies
N2 - Reliable and straightforward characterization and analysis of carbon-based nanomaterials on the atomic level is essential to exploring their potential for application. Here we use a combination of highly surface sensitive x-ray photoelectron (XP) spectroscopy and near edge x-ray absorption fine structure spectroscopy (NEXAFS) to study and quantify the covalent functionalization of nanographene and single-walled carbon nanotubes with nitrene [2 + 1]-cycloaddition. With this comprehensive analytical approach, we demonstrate that the π-conjugated system of functionalized carbon-based nanomaterials is preserved according to NEXAFS analysis, which is challenging to prove with XP spectroscopy investigation alone. Using this combination of analytical approaches, we show significant similarities after functionalization for various carbon-based nanomaterials. Both analytical methods are strongly suited to study possible post-modification reactions of functionalized carbon-based nanomaterials.
KW - Graphene
KW - Carbon nanotubes
KW - Covalend functionalization
PY - 2023
DO - https://doi.org/10.1016/j.apsusc.2022.155953
VL - 613
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-56865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Co0.75Fe2.25O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Co0.75Fe2.25O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Co0.75Fe2.25O4 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7940769
PB - Zenodo
CY - Geneva
AN - OPUS4-57664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Ce0.75Zr0.25O2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Ce0.75Zr0.25O2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Ce0.75Zr0.25O2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7966133
PB - Zenodo
CY - Geneva
AN - OPUS4-57673
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Ce0.1Zr0.9O2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Ce0.1Zr0.9O2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Ce0.1Zr0.9O2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7965602
PB - Zenodo
CY - Geneva
AN - OPUS4-57672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Co3O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Co3O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Co3O4 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7941248
PB - Zenodo
CY - Geneva
AN - OPUS4-57666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized ZrO2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized ZrO2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - ZrO2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7965536
PB - Zenodo
CY - Geneva
AN - OPUS4-57671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Pfüger, Mika
A1 - Velasco-Vélez, Juan-Jesús
A1 - Sahre, Mario
A1 - Radnik, Jörg
A1 - Bernicke, Michael
A1 - Bernsmeier, Denis
A1 - Hodoroaba, Vasile-Dan
A1 - Krumrey, Michael
A1 - Strasser, Peter
A1 - Kraehnert, Ralph
A1 - Hertwig, Andreas
T1 - Assessing optical and electrical properties of highly active IrOx catalysts for the electrochemical oxygen evolution reaction via spectroscopic ellipsometry
N2 - Efficient water electrolysis requires highly active electrodes. The activity of corresponding catalytic coatings strongly depends on material properties such as film thickness, crystallinity, electrical conductivity, and chemical surface speciation. Measuring these properties with high accuracy in vacuum-free and nondestructive methods facilitates the elucidation of structure−activity relationships in realistic environments. Here, we report a novel approach to analyze the optical and electrical properties of highly active oxygen evolution reaction (OER) catalysts via spectroscopic ellipsometry (SE). Using a series of differently calcined, mesoporous, templated iridium oxide films as an example, we assess the film thickness, porosity, electrical resistivity, electron concentration, electron mobility, and interband and intraband transition energies by modeling of the optical spectra. Independently performed analyses using scanning electron microscopy, energy-dispersive X-ray spectroscopy, ellipsometric porosimetry, X-ray reflectometry, and absorption spectroscopy indicate a high accuracy of the deduced material properties. A comparison of the derived analytical data from SE, resonant photoemission spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy with activity measurements of the OER suggests that the intrinsic activity of iridium oxides scales with a shift of the Ir 5d t2g sub-level and an increase of p−d interband transition energies caused by a transition of μ1-OH to μ3-O species.
KW - Spectroscopic ellipsometry
KW - Electrocatalysis
KW - Oxygen evolution reaction
KW - Mesoporous iridium oxide films
KW - Non-destructive ambient analysis
KW - Intrinsic OER activity
KW - Complementary methodology and metrology
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516288
DO - https://doi.org/10.1021/acscatal.0c03800
SN - 2155-5435
VL - 10
IS - 23
SP - 14210
EP - 14223
PB - American Chemical Society
AN - OPUS4-51628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - EMPIR nPSize - Improved Traceability Chain of Nanoparticle Size Measurement
N2 - In order to assess new nanomaterials and nanoparticles for potential risks to health and the environment, they need to be well-characterised. The measurement of constituent nanoparticle size, shape, and size distribution are important factors for the risk evaluation process.
EMPIR project Improved traceability chain of nanoparticle size measurements (17NRM04, nPSize) is working to assess a range of traceable nanoparticle measurement approaches, including Electron Microscopy (SEM, TEM, STEM-in-SEM), Atomic Force Microscopy and Small Angle X-ray Scattering, and deliver improved calibration methods to users. For the techniques under investigation, physical models of their response to a range of nanoparticle types are developed. Validated reference materials are also used for inter-comparisons of measurement systems, with an evaluation of the associated measurement uncertainty. With project contributions to standards development work, manufacturers will be better placed to assess the human and environmental risks posed by nanomaterials across a whole range of products.
T2 - EMPIR nPSize Training Course "Traceable Characterization of Nanoparticles by SAXS"
CY - Online meeting
DA - 01.02.2021
KW - Nanoparticles
KW - Particle size distribution
KW - Traceability
KW - nPSize
KW - SAXS
PY - 2021
AN - OPUS4-53883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Preliminary results of an interlaboratory comparison on microplastics organised by plasticsfate
N2 - Microplastics are everywhere in the environment, but analytics is challenging. Since harmonisation is missing as well es suitable reference materials, BAM did under th umbrella of VAMAS funded by the EU Horizon 2020 project PlasticsFate a ILC for microplastic detection methods. Methods adressed were IR, Raman, Py-GC/MS and TED-GC/MS. The talk gives a first presentation and evaluation on the results.
T2 - CUSP annual meeting and conference
CY - Utrecht, Netherlands
DA - 12.09.2023
KW - Microplastics
KW - TED-GC/MS
KW - Polymer 3R
KW - Reference material
KW - ILC on detection methods
PY - 2023
AN - OPUS4-60036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, Heike
A1 - Knigge, Xenia
A1 - Knapic, D.
A1 - Weise, Matthias
A1 - Sahre, Mario
A1 - Hertwig, Andreas
A1 - Sacco, A.
A1 - Rossi, A. M.
A1 - Radnik, Jörg
A1 - Müller, Kai
A1 - Wasmuth, Karsten
A1 - Krüger, Jörg
A1 - Hassel, A. W.
A1 - Hodoroaba, Vasile-Dan
A1 - Bonse, Jörn
T1 - Picosecond laser processing of hierarchical micro–nanostructures on titanium alloy upon pre- and postanodization: morphological, structural, and chemical effects
N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser processing step) plays an important role for the response of bone-forming osteoblasts—an effect that can be utilized for improving permanent dental or removable bone implants. For exploring these different surface functionalities, multimethod morphological, structural, and chemical characterizations are performed in combination with electrochemical pre- and postanodization for two different characteristic microspikes covered by nanometric laser-induced periodic surface structures on Ti–6Al–4V upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ≈1 ps pulse duration, 67 and 80 kHz pulse repetition frequency) at two distinct sets of laser fluence and beam scanning parameters. This work involves morphological and topographical investigations by scanning electron microscopy and white light interference microscopy, structural material examinations via X-ray diffraction, and micro-Raman spectroscopy, as well as near-surface chemical analyses by X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy. The results allow to qualify the mean laser ablation depth, assess the spike geometry and surface roughness parameters, and provide new detailed insights into the near-surface oxidation that may affect the different cell growth behavior for pre- or postanodized medical implants.
T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - Hierarchical micro-nanostructures
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
KW - Ti-6Al-4V alloy
KW - X-ray photoelectron spectroscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601962
DO - https://doi.org/10.1002/pssa.202300920
SN - 1862-6319
SP - 1
EP - 11
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-60196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giovannozzi, A
T1 - Standardization and Harmonization Effort on Microplastics Analysis by Spectroscopic Methods
N2 - This talk presents the EU funded project PlasticTrace. It shows the challenges in micro- and nanoplastic reference materials and gives some solutions regarding spectroscipc methods such as Raman or IR microscopy to determine the particle numbers. Materials are prepared by cryo milling to get some powder that is later pressed into tablets. The polymer type used is PET, because that is highly important for drinking water directive of EU commission.
T2 - International Conference on Raman Spectroscopy (ICORS)
CY - Roma, Italy
DA - 28.07.2024
KW - Microplastics
KW - Reference materials
KW - Polymer 3R
PY - 2024
AN - OPUS4-60881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bennet, Francesca
T1 - Microprinting and SEM analysis for quantitative evaluation of nanoparticles in solution
N2 - Nanoparticle suspensions were microprinted onto TEM grids for subsequent analysis by SEM/TSEM and evaluation of particle numbers using Image J software. Various nanoparticle types, concentrations and printing conditions (temperature, rel. humidity) were evaluated in order to determine the optimal conditions for producing a uniform distribution of particles on the substrate and eliminating the coffee ring effect.
T2 - H2020 ACEnano Project Meeting
CY - Amsterdam, Netherlands
DA - 04.03.2020
KW - Nanoparticle
KW - Imaging
KW - Microprinting
KW - Homogeneous deposition
PY - 2020
AN - OPUS4-50584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cant, D. J. H.
A1 - Müller, Anja
A1 - Clifford, C. A.
A1 - Unger, Wolfgang
A1 - Shard, A. G.
T1 - Summary of ISO/TC 201 Technical Report 23173—Surface chemical analysis—Electron spectroscopies—Measurement of the thickness and composition of nanoparticle coatings
N2 - ISO Technical Report 23173 describes methods by which electron spectroscopies, including X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and synchrotron techniques, can be employed to calculate the Coating thicknesses and compositions of nanoparticles. The document has been developed to review and outline the current state-of-the-art for such measurements. Such analyses of core–shell nanoparticles are common within the literature, however the
methods employed are varied; the relative advantages and disadvantages of These methods, and the optimal usage of each may not be clear to the general analyst. ISO Technical Report 23173 aims to clarify the methods that are available, describe them in clear terms, exhibit examples of their use, and highlight potential issues users may face. The information provided should allow analysts of electron spectroscopy data to make clear choices regarding the appropriate analysis of electron spectroscopy data from coated nanoparticle systems and provide a basis for understanding and comparing results from different methods and systems.
KW - Electron spectroscopy
KW - Core-shell
KW - Nanoparticles
KW - ISO 23173
KW - XPS
KW - Thickness
KW - Composition
PY - 2021
DO - https://doi.org/10.1002/sia.6987
SN - 0142-2421
VL - 53
IS - 10
SP - 893
EP - 899
PB - John Wiley & Sons Ltd
AN - OPUS4-52976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Characterization of nanoparticles - Measurement processes for nanoparticles
N2 - Characterization of Nanoparticles: Measurement Processes for Nanoparticles surveys this fast growing field, including established methods for the physical and chemical characterization of nanoparticles. The book focuses on sample preparation issues (including potential pitfalls), with measurement procedures described in detail. In addition, the book explores data reduction, including the quantitative evaluation of the final result and its uncertainty of measurement. The results of published inter-laboratory comparisons are referred to, along with the availability of reference materials necessary for instrument calibration and method validation. The application of these methods are illustrated with practical examples on what is routine and what remains a challenge.
In addition, this book summarizes promising methods still under development and analyzes the need for complementary methods to enhance the quality of nanoparticle characterization with solutions already in operation.
KW - Nanoparticles
KW - Characterization method
KW - Sample preparation
KW - Inter-laboratory comparison
KW - Standardisation
KW - Measurement uncertainty
KW - Case studies
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/C2017-0-00312-9
SP - 1
EP - 566
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dietrich, P. M.
A1 - Kjærvik, Marit
A1 - Willneff, E. A.
A1 - Unger, Wolfgang
T1 - In-depth analysis of iodine in artificial biofilm model layers by variable excitation energy XPS and argon gas cluster ion sputtering XPS
N2 - Here, we present a study on agarose thin-film samples that represent a model system for the exopolysaccharide matrix of biofilms. Povidone-iodide (PVP-I) was selected as an antibacterial agent to evaluate our x-ray photoelectron spectroscopy (XPS)-based methodology to trace specific marker elements, here iodine, commonly found in organic matrices of antibiotics. The in-depth distribution of iodine was determined by XPS analyses with variable excitation energies and in combination with argon gas cluster ion beam sputter cycles. On mixed agarose/PVP-I nanometer-thin films, both methods were found to solve the analytical task and deliver independently comparable results. In the mixed agarose/PVP-I thin film, we found the outermost surface layer depleted in iodine, whereas the iodine is homogeneously distributed in the depth region between this outermost surface layer and the interface between the thin film and the substrate. Depletion of iodine from the uppermost surface in the thin-film samples is assumed to be caused by ultrahigh vacuum exposure resulting in a loss of molecular iodine (I2) as reported earlier for other iodine-doped polymers.
KW - Biofilm
KW - XPS
KW - Argon gas cluster ion sputtering
KW - Variable excitation
KW - Iodine
PY - 2022
DO - https://doi.org/10.1116/6.0001812
SN - 1934-8630
VL - 17
IS - 3
SP - 1
EP - 8
PB - AVS
AN - OPUS4-54973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezera, Marek
T1 - Influence of the pulse repetition rate on the chemical and morphological properties of laser generated surface structures
N2 - Inter-pulse accumulation of heat could affect the chemical and morphological properties of the laser processed material surface. Hence, the laser pulse repetition rate may restrict the processing parameters for specific laser-induced surface structures. In this study, the evolution of various types of laser-induced micro- and nanostructures at various laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz) are studied for common metals/alloys (e.g. steel or titanium alloy) irradiated by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment. The processed surfaces were characterized by optical and scanning electron microscopy (OM, SEM), energy dispersive X-ray spectroscopy (EDX) as well as time of flight secondary ion mass spectrometry (TOF-SIMS). The results show that not only the surface morphology could change at different laser pulse repetition rates and comparable laser fluence levels and effective number of pulses, but also the surface chemistry is altered. Consequences for medical applications are outlined.
T2 - European Materials Research Society Spring 2021 Meeting
CY - Online meeting
DA - 31.05.2021
KW - Laser-induced pariodic surface structures
KW - LIPSS
PY - 2021
AN - OPUS4-52778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, F.
A1 - Sordello, F.
A1 - Mino, L.
A1 - Prozzi, M.
A1 - Mansfeld, Ulrich
A1 - Hodoroaba, Vasile-Dan
A1 - Minero, C.
T1 - Polyethylene Glycol as Shape and Size Controller for the Hydrothermal Synthesis of SrTiO3 Cubes and Polyhedra
N2 - Understanding the correlation between the morphological and functional properties of particulate materials is crucial across all fields of physical and natural sciences. This manuscript reports on the investigation of the effect of polyethylene glycol (PEG) employed as a capping Agent in the synthesis of SrTiO3 crystals. The crucial influence of PEG on both the shape and size of the strontium titanate particles is revealed, highlighting the effect on the photocurrents measured under
UV–Vis irradiation.
KW - Polyethylene glycol
KW - Strontium titanate
KW - Controlled morphology
KW - Photoelectrochemistry
KW - Electron microscopy
KW - EDS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512892
DO - https://doi.org/10.3390/nano10091892
VL - 10
IS - 9
SP - 1892
PB - MDPI
CY - Basel, CH
AN - OPUS4-51289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Standardized Chemical Composition Analysis of Graphene Oxide Flakes with SEM/EDS and XPS Works Reliably
N2 - Reliable quantification of the chemical composition of graphene-related 2D materials (GR2M) as powders and liquid suspensions is a challenging task. Analytical methods such as XPS, ICP-MS, TGA and FTIR are recommended in projects at standardization bodies. The parameters to be measured are also defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present. In this contribution, for the first time, the capability of SEM/EDS to reliably quantify the O/C ratio in a well-characterized graphene oxide (GO) material is evaluated. The robustness of the SEM/EDS results under various measurement conditions is tested by comparison to the established XPS analysis.
A crucial step is the sample preparation from liquid suspension with GO flakes onto a substrate for analysis with both EDS and XPS. It is demonstrated that if a closed and enough thick drop-cast spot is deposited on a substrate, both surface-sensitive XPS analysis and bulk-characterizing EDS result in very similar elemental composition of oxygen and carbon. Hence, the theoretical, expected O/C atomic ratio values for pure GO of ~0.5 are achieved with both methods. Further, the effect of untight deposited material causing co-analysis of the silicon substrate, is evaluated for both methods, XPS and EDS. Note that all the EDS results in this study have been quantified standardless.
The standard measurement procedure including the GO material considered here as a candidate reference material will make a significant contribution to analyse reliably the chemical composition of GR2M with SEM/EDS as one of the most widely used methods in analytical laboratories.
T2 - Graphene Week 2025
CY - Vicenza, Italy
DA - 22.09.2025
KW - EDX
KW - Graphene-related 2D materials
KW - O/C ratio
KW - Standardisation
KW - Samle preparation
KW - XPS
PY - 2025
AN - OPUS4-64261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Corrao, Elena
A1 - Pellegrino, Francesco
A1 - Hodoroaba, Vasile-Dan
T1 - Wire-Print as a Sample Preparation Procedure Suitable for Accurate Morphological Characterization of Constituent Particles for Graphene-Related 2D-Materials
N2 - In this study we have systematically tested the efficacy of a new deposition procedure for graphene-related 2D materials (GR2M’s) from liquid suspension onto a substrate for quantitative analysis of their size and shape distribution with electron microscopy.
The technique is an extension of the conventional drop-casting method, and we have designated it “wire-print” deposition. It consists of two steps, first one being usual drop-casting on a copper substrate and second one involving a thin copper wire with a sub-mm diameter being dipped into the deposited droplet and retracted with a corresponding half-spherical droplet attached on its tip and final deposition of this entire nL-amount of suspension onto e.g. a silicon wafer for microscopical, detailed analysis. 11 series of such a wire-print deposition for a graphene-based ink have been considered, whereby various conditions (treatment of the starting suspension) have been experimented with a repetition of up to 10 times per condition, all together 86 spots on a silicon wafer of 10 mm x 10 mm. The evaluation of one series of 8 repeated wire-print depositions reveal that the deposited spots are visualized with SEM. The weak presence of coffee-rings, irregular spot shape, and presence of agglomerates should be noticed. Both the mean value of the 8 ECD distributions and the total number of flakes deposited in each spot show a variance in the range of 17% and 22%, respectively. In the context of accurate analysis of such challenging complex materials these numbers can be considered as excellent and demonstrate the high benefit of the wire-print deposition for accurate morphological measurements on GR2M’s.
KW - Sample preparation
KW - Imaging
KW - 2D materials
KW - Morphology
KW - Size distribution
PY - 2025
DO - https://doi.org/10.1093/mam/ozaf048.219
VL - 31
IS - 7
SP - 436
EP - 437
PB - Oxford Academic
AN - OPUS4-63821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marcoulaki, E.
T1 - Blueprint for a sustainable new European Centre to support safe innovation for nanotechnology
N2 - This paper presents the blueprint for the operation of a sustainable and permanent European Centre of collaborating reference laboratories and research centres, to establish a one-stop shop for a wide variety of nanosafety related services, and to provide a central contact point for questions about nanosafety in Europe. The Centre aims to harmonise service provision, and bring novel risk assessment and management approaches closer to practice.
T2 - NANOSAFE 2020
CY - Online meeting
DA - 16.11.2020
KW - EC4SafeNano
KW - European Centre
KW - Nanomaterials
KW - Nanosafety
KW - Catalogue of Services (CoS)
PY - 2020
UR - https://www.nanosafe.org/cea-tech/pns/nanosafe/en
AN - OPUS4-51694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Habibimarkani, Heydar
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - John, Elisabeth
T1 - Probing Surface Changes in Fe–Ni Oxide Nanocatalysts with a ToF-SIMS-Coupled Electrochemistry Setup and Principal Component Analysis
N2 - Understanding catalyst surface dynamics under operating conditions is essential for improving electrocatalytic performance. Here, we present a novel approach combining electrochemical treatment with contamination-free transfer to Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), followed by principal component analysis (PCA), to probe surface and interfacial changes in Ni–Fe oxide nanoparticles stabilized by polyvinylpyrrolidone (PVP) during the oxygen evolution reaction (OER). The surface analysis at three distinct treatment stages revealed distinct chemical fingerprints across pristine nanoparticles, after exposure to 1 M KOH electrolyte, and after cyclic voltammetry treatment. The results highlight a progressive transition from ligand-rich to ligand-depleted interfaces, with PVP-related fragments dominant in the early stages and metal- and electrolyte-derived species emerging after activation. Complementary ToF-SIMS analysis of electrolyte deposited on Si wafers after each treatment step confirms the concurrent leaching of PVP and Fe–Ni-based fragments during OER. These findings underscore the dynamic nature of catalyst–electrolyte interfaces and demonstrate a robust strategy for monitoring surface-sensitive chemical changes associated with the nanoparticles, especially during the initial cycles of the OER.
KW - Fe-Ni oxide
KW - Nanocatalysts
KW - ToF-SIMS
KW - Electrochemistry
KW - PCA (principal component analysis)
KW - OER
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652667
DO - https://doi.org/10.1021/acs.analchem.5c03894
SN - 0003-2700
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-65266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mirabella, Francesca
T1 - ToF-SIMS as a new tool for nano-scale investigation of ps-laser-generated surface structures on titanium substrates
N2 - In recent years, the fabrication of laser-generated surface structures on metals such as titanium surfaces have gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces.
The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, laser light polarization type and direction, angle of incidence, and the effective number of laser pulses per beam spot area.
However, the characterization of the different surface structures can be difficult because of constraints regarding the analytical information from both depth and the topographic artifacts which may limit the lateral and depth resolution of elemental distributions as well as their proper quantification. A promising technique to investigate these structures even at the nano-scale is Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), a very surface sensitive technique that at the same time allows to perform depth-profiling, imaging and 3D-reconstruction of selected ion-sputter fragment distributions on the surface.
In this study we combine chemical analyses such as Energy Dispersive X-ray spectroscopy (EDX) and high-resolution scanning electron microscopy (SEM) analyses with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti and Ti alloys at different laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz), following irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment or under argon gas flow.
We show how this combined surface analytical approach allows to evaluate alteration in the surface chemistry of the laser-generated surface structures depending on the laser processing parameters and the ambient environment.
T2 - European Materials Research Society (EMRS) Fall Meeting 2021
CY - Online meeting
DA - 20.09.2021
KW - ToF SIMS
KW - Nano characterization
PY - 2021
AN - OPUS4-53366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Morphological and Chemical Nanoscale Analysis of Mesoporous Mixed IrO x TiO y Thin Films as Electrode Materials
N2 - Porous films play an important role particularly in energy applications like photovoltaics, electrolysis or batteries. Thin film properties such as thickness, chemical composition, crystallinity of the framework, and porosity define the activity of the porous films. The accurate morpho-chemical characterisation of mesoporous thin films is a challenging analytical task which requires the consideration of new analytical approaches based on the combination of data of different methods able to address the structure and chemical composition at the nanoscale. In this contribution we characterise thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with Energy-Dispersive X-ray Spectroscopy (EDS) at an SEM applied in a dedicated “thin film analysis” approach (1). Thus, the film mass deposition, film thickness and the film density can be determined. Further, by dividing the measured film density to an assumed (theoretical) metal oxide framework (skeletal) density, the thin film porosity can be extracted, too.
In order to assess the homogeneity of the thin film properties like the chemical composition, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Auger Electron Spectrometry are applied in the depth profiling mode, so that possible in-depth gradients are detected. Lateral inhomogeneities in the chemical composition and structure of the thin mesoporous films are also identified by applying the same methods in the line-scan or mapping mode, which can be further combined with in-depth sputtering for 3D information. The role of the spatial resolution of the analytical methods considered, which can go down well below 100 nm, will be highlighted.
T2 - Microscopy and Microanalysis 2024
CY - Cleveland, OH, USA
DA - 28.07.2024
KW - Auger electron spectroscopy
KW - Iridium oxide
KW - Mesoporous thin films
KW - SIMS
KW - Titanium oxide
KW - Porosity
PY - 2024
AN - OPUS4-60805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Harald
A1 - Hodoroaba, Vasile-Dan
A1 - Schmidt, Alexandra
A1 - Rasmussen, K.
A1 - Rauscher, H.
T1 - Counting Small Particles in Electron Microscopy Images — Proposal for Rules and Their Application in Practice
N2 - Electron microscopy (EM) is the gold standard for the characterisation of the morphology (size and shape) of nanoparticles. Visual observation of objects under examination is always a necessary first step in the characterisation process. Several questions arise when undertaking to identify and count particles to measure their size and shape distribution. In addition to challenges with the dispersion and identification of the particles, more than one protocol for counting particles is in use. This paper focuses on precise rules for the counting of particles in EM micrographs, as this influences the measurement accuracy of the number of particles, thus implicitly affecting the size values of the counted particles. We review and compare four different, commonly used methods for counting, which we then apply in case studies. The impact of the selected counting rule on the obtained final particle size distribution is highlighted. One main aim of this analysis is to support the application of a specific, well-defined counting approach in accordance with regulatory
requirements to contribute to achieving more reliable and reproducible results. It is also useful for the new harmonised measurement procedures for determining the particle size and particle size distribution of nanomaterials.
KW - Nano
KW - Particle size distribution
KW - Nanoparticle
KW - Nanomaterial
KW - OECD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551891
DO - https://doi.org/10.3390/nano12132238
SN - 2079-4991
VL - 12
IS - 13
SP - 2238
PB - MDPI
CY - Basel
AN - OPUS4-55189
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hülagü, Deniz
A1 - Tobias, Charlie
A1 - Dao, R.
A1 - Komarow, P.
A1 - Rurack, Knut
A1 - Hodoroaba, Vasile-Dan
T1 - Dataset accompanying the publication "Towards 3D determination of the surface roughness of core-shell microparticles as a routine quality control procedure by scanning electron microscopy"
N2 - This dataset accompanies the following publication:
Hülagü, D., Tobias, C., Dao, R., Komarov, P., Rurack, K., Hodoroaba, V.-D., Towards 3D determination of the surface roughness of core-shell microparticles as a routine quality control procedure by scanning electron microscopy. Sci.Rep, 14, 17936 (2024), https://doi.org/10.1038/s41598-024-68797-7.
It contains SEM and AFM-in-SEM images of polystyrene (PS) core particles, polystyrene-iron oxide (PS/Fe3O4) core-shell particles, and polystyrene-iron oxide-silica (PS/Fe3O4/SiO2) core-shell-shell particles. Please refer to the publication and its supporting information for more details on the acquisition and contents of the dataset, as well as the GitHub repository at https://github.Com/denizhulagu/roughness-analysis-by-electron-microscopy.
The investigated particles were produced at BAM laboratories as previously described in:
Hülagü, D. et al. Generalized analysis approach of the profile roughness by electron microscopy with the example of hierarchically grown polystyrene–iron oxide–silica core–shell–shell particles. Adv. Eng. Mater. 24, 2101344, https://doi.org/10.1002/adem.202101344 (2022).
Tobias, C., Climent, E., Gawlitza, K. & Rurack, K. Polystyrene microparticles with convergently grown mesoporous silica shells as a promising tool for multiplexed bioanalytical assays. ACS Appl. Mater. Interfaces 13, 207, https://dx.doi.org/10.1021/acsami.0c17940 (2020).
KW - Core–shell particles
KW - Image analysis
KW - Roughness
KW - Scanning electron microscopy
KW - Atomic force microscopy
KW - Tilting
KW - Batch analysis
PY - 2024
UR - https://zenodo.org/records/11108726
DO - https://doi.org/10.5281/zenodo.11108725
PB - Zenodo
CY - Geneva
AN - OPUS4-60760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Terborg, R.
A1 - Boehm, S.
A1 - Kim, K. J.
T1 - Analysis of elemental composition of Fe1-xNix and Si1-xGex alloy thin films by electron probe microanalysis and micro-focus X-ray fluorescence
N2 - The present study reports on results of analysis of the elemental composition of thin films by electron probe microanalysis with energy dispersive (ED-EPMA) X-ray spectrometry in conjunction with the dedicated thin-film analysis software package Stratagem and by X-ray fluorescence in its version with a micro-focus X-ray fluorescence (μ-XRF) source attached to a scanning electron microscope (SEM). Two thin-film systems have been analyzed: Fe1-xNix on silicon wafer and Si1-xGex on Al2O3 substrate, in both cases the layers being grown to a thickness of about 200 nm by ion beam sputter deposition. Samples of five different atomic fractions have been produced and analyzed for each thin-film system. Moreover, reference samples with certified elemental composition and thickness have been also available. This study is part of an interlaboratory comparison organized in the frame of standardization technical committee ISO/TC 201 “Surface chemical analysis.” Two laboratories have been analyzed by ED-EPMA (one laboratory standardless and one laboratory using both standardless and with standards variants) and one laboratory by μ-XRF (standardless and with standards). All the elemental compositions obtained with different methods are in very good agreement for the complete two sets of five samples each.
KW - Thin films
KW - Elemental composition
KW - FeNi
KW - SiGe
KW - Electron probe microanalysis
KW - X-ray Fluorescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509262
DO - https://doi.org/10.1002/sia.6834
SN - 0142-2421
VL - 52
IS - 12
SP - 929
EP - 932
PB - John Wiley & Sons Ltd
AN - OPUS4-50926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Ce0.25Zr0.75O2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Ce0.25Zr0.75O2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Ce0.25Zr0.75O2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7966165
PB - Zenodo
CY - Geneva
AN - OPUS4-57674
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Co1.5Fe1.5O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Co1.5Fe1.5O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Co1.5Fe1.5O4 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7940271
PB - Zenodo
CY - Geneva
AN - OPUS4-57662
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized TiO2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized TiO2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - TiO2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7941566
PB - Zenodo
CY - Geneva
AN - OPUS4-57668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized TiO2 PVP nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized TiO2 PVP nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Nanoparticles
KW - TiO2 PVP
PY - 2023
DO - https://doi.org/10.5281/zenodo.7966354
PB - Zenodo
CY - Geneva
AN - OPUS4-57761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterile ZnO nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of ZnO nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Nanoparticles
KW - ZnO
PY - 2023
DO - https://doi.org/10.5281/zenodo.7990213
PB - Zenodo
CY - Geneva
AN - OPUS4-57762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of Ce0.9Zr0.1O2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of Ce0.9Zr0.1O2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Ce0.9Zr0.1O2
KW - Nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7986672
PB - Zenodo
CY - Geneva
AN - OPUS4-57758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterile citrated stabilized Au nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of Au nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - HAXPES
KW - XPS
KW - SEM
KW - Au Nanoparticles
KW - NanoSolveIT
PY - 2023
DO - https://doi.org/10.5281/zenodo.7990250
PB - Zenodo
CY - Geneva
AN - OPUS4-57763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Rühle, Bastian
A1 - Kuchenbecker, Petra
A1 - Löhmann, Oliver
A1 - Lindemann, Franziska
A1 - Hodoroaba, Vasile-Dan
T1 - Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders
N2 - Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed.
KW - Nanopowder
KW - Electron microscopy
KW - Sample preparation
KW - Cross-sectioning
KW - Cerium oxide
KW - Zinc oxide
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593289
DO - https://doi.org/10.1038/s41598-023-51094-0
SN - 2045-2322
VL - 14
SP - 1
EP - 10
PB - Springer Nature
CY - London
AN - OPUS4-59328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - López de Ipina, J.-M.
A1 - Arevalillo, A.
A1 - Martín, A.
A1 - Caillard, B.
A1 - Marcoulaki, E.
A1 - Aguerre- Charol, O.
A1 - van Duuren-Stuurman, B.
A1 - Hodoroaba, Vasile-Dan
A1 - Viitanen, A.-K.
A1 - Witters, H.
A1 - Vercauteren, S.
A1 - Persson, K.
A1 - Bard, D.
A1 - Evans, G.
A1 - Jensen, K.A.
A1 - Himly, M.
A1 - Scalbi, S.
A1 - Papin, A.
A1 - Le Bihan, O.
A1 - Kanerva, T.
A1 - Tirez, K.
A1 - Frijns, E.
A1 - Niga, P.
A1 - Eleftheriadis, K.
A1 - Travlos, A.
A1 - Geppert, M.
A1 - Himly, M.
A1 - Radnik, Jörg
A1 - Kuchenbecker, Petra
A1 - Resch-Genger, Ute
A1 - Fraboulet, I.
A1 - Bressot, C.
A1 - Rissler, J.
A1 - Gaucher, R.
A1 - Binotto, G.
A1 - Krietsch, Arne
A1 - Braun, A.
A1 - Abenet, S.
A1 - Catalan, J.
A1 - Verstraelen, S.
A1 - Manier, N.
A1 - Manzo, S.
A1 - Fransman, S.
A1 - Queron, J.
A1 - Charpentier, D.
A1 - Taxell, D.
A1 - Säämänen, A.
A1 - Brignon, J.-M.
A1 - Jovanovic, A.
A1 - Bisson, M
A1 - Neofytou, P.
T1 - EC4Safenano - Catalogue of Services
N2 - The publicly available document encapsulates the first version of the Catalogue of Services of the future EC4Safenano Centre (CoS 2019).
The CoS 2019 is structured in 12 Service Categories and 27 Service Topics, for each of the 12 categories considered. This architecture configures a 12 x 27 matrix that allows ordering the potential EC4Safenano offer in 324 types of services/groups of services.
Each type of service/group of services is described, in a simple and friendly way, by means of a specific service sheet: the EC4Safenano - Service Data Sheet (EC4-SDS). These EC4-SDSs allow structuring and summarizing the information of each service, providing the customer with a concise view of characteristics of the service and also the contact details with the service provider.
The CoS 2019 deploys a map of services consisting of a set of 100 EC4-SDSs, covering 7 of the 12 Service Categories and 17 of the 27 Service Topics.
The harmonization of services is visualized as a future necessary step in EC4Safenano, in order to strengthen the offer and provide added value to customers with a growing offer of harmonized services in future versions of the CoS.
The information contained in this document is structured in 3 main sections, as follows:
• Catalogue structure. This section describes in short the main characteristics of the CoS 2019.
• Catalogue content. This section represents the core part of the document and encapsulates the set of 100 SDSs displaying the offer proposed by the CoS 2019.
• Online Catalogue. This section describes the resources implemented by EC4Safenano to facilitate the on-line consultation of the CoS 2019 by customers and other interested parties.
KW - Nano-safety
KW - Analytical services
KW - Nanomaterials
KW - Catalogue of services
KW - EC4SafeNano
KW - European Centre
PY - 2021
UR - https://ec4safenano.eu-vri.eu/Public/Guidance
SP - 1
EP - 72
PB - EU-VRi – European Virtual Institute for Integrated Risk Management
CY - Stuttgart, Germany
AN - OPUS4-52943
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, F.
A1 - Isopescu, R.
A1 - Pellutiè, L.
A1 - Sordello, F.
A1 - Rossi, A. M.
A1 - Ortel, Erik
A1 - Martra, G.
A1 - Hodoroaba, Vasile-Dan
A1 - Maurino, V.
T1 - Machine learning approach for elucidating and predicting the role of synthesis parameters on the shape and size of TiO2 nanoparticles
N2 - In the present work a series of design rules are developed in order to tune the morphology of TiO2 nanoparticles through hydrothermal process. Through a careful experimental design, the influence of relevant process parameters on the synthesis outcome are studied, reaching to the develop predictive models by using Machine Learning methods. The models, after the validation and training, are able to predict with high accuracy the synthesis outcome in terms of nanoparticle size, polydispersity and aspect ratio. Furthermore, they are implemented by reverse engineering approach to do the inverse process, i.e. obtain the optimal synthesis parameters given a specific product characteristic. For the first time, it is presented a synthesis method that allows continuous and precise control of NPs morphology with the possibility to tune the aspect ratio over a large range from 1.4 (perfect truncated bipyramids) to 6 (elongated nanoparticles) and the length from 20 to 140 nm.
KW - Machine learning
KW - Nanoparticles
KW - Titanium dioxide
KW - Size
KW - Shape
KW - Synthesis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515084
DO - https://doi.org/10.1038/s41598-020-75967-w
VL - 10
IS - 1
SP - 18910
PB - Springer Nature
AN - OPUS4-51508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmed, R.
A1 - Vaishampayan, A.
A1 - Cuellar-Camacho, J. L.
A1 - Wight, D. J.
A1 - Donskyi, Ievgen
A1 - Unger, Wolfgang
A1 - Grohmann, E.
A1 - Haag, R.
A1 - Wagner, O.
T1 - Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density
N2 - Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction.
Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time.
This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies.
KW - Surface charge
KW - Bacteria
KW - Graphene oxide
KW - Escherichia coli
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509651
DO - https://doi.org/10.1002/admi.201902066
VL - 7
IS - 15
SP - 1902066
PB - WILEY-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
A1 - Weber, Mike
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Numerical Modelling of Compression Stress Relaxation and Compression Set of Elastomer O-Ring During Aging
N2 - Elastomer seals are used in many industrial applications due to their excellent mechanical properties at a wide range of temperatures. Their high versatility and recovery potential under several load conditions make them well suitable for the application in containers designed for transport, storage and/or disposal of radioactive materials. In containers for low and intermediate level radioactive waste, elastomer seals are used as barrier seals, and as auxiliary seals in storage and transportation casks (dual purpose casks) for heat generating radioactive waste, such as spent fuel and high-level waste. While a seal exchange at defined intervals is typical in many conventional applications, it is impossible or at least hard to perform when principles of minimization of radiation exposure have to be considered and prohibit an unnecessary cask handling. An extensive knowledge of the change of the elastomer’s properties during aging and the availability of reliable end-of-lifetime criteria to guarantee the permanent safe enclosure of the radioactive material is mandatory. As BAM is involved in most of the national cask licensing procedures and in the evaluation of cask-related long-term safety issues, great efforts have been already made and are still planned to scientifically support this task.
Compression stress relaxation and compression set were identified as key indicators of elastomer long-term performance and quantitatively investigated in comprehensive test programs. Among other representative types of elastomers, specimens made from ethylene propylene diene rubber (EPDM) were tested before, during and after aging to capture the most important of their complex mechanical properties.
In the presented study, exemplary results were used to simulate the compression stress relaxation and the compression set of elastomer O-rings during aging. Regarding the influence of temperature, the time-temperature superposition principle is applied in the relaxation analysis of elastomer O-rings. The proposed model is implemented in the commercial finite element software ABAQUS/Standard® [1] with a sequential temperature displacement coupling. Numerical results match the experimental compression stress relaxation measurements well. The prediction of compression set values after long-term aging shows a relatively good agreement with the experimental results. Nevertheless, all input parameters derived from the specimen tests, additional assumptions concerning boundary conditions and modeling strategy are discussed with regard to the identified slight discrepancies.
The possibility to extend the finite element model to represent the O-ring seal’s ability to recover after a (fast) partial release is taken into account.
T2 - ASME 2020 Pressure Vessels & Piping Conference (PVP2020)
CY - Online meeting
DA - 03.08.2020
KW - Compression Set
KW - O-ring
KW - Simulation
KW - Sequential analysis
KW - Ageing
KW - stress relaxation
PY - 2020
SN - 978-0-7918-8388-4
DO - https://doi.org/10.1115/PVP2020-21270
SP - PVP2020-21270
PB - ASME
AN - OPUS4-51490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - MinimUm Information Requirements for Electron Microscopy and Surface analysis Data For Risk Assessment of Nanoforms
N2 - The European legislation has responded to the wide use of nanomaterials in our daily life and defined the term “nanoform” in the Annexes to the REACH (Registration, Evaluation, Authorization of Chemicals) Regulation. Now specific information of the nanomaterials is required from the companies when registering the appropriate materials in a dossier.
In the context of REACH eleven physicochemical properties were considered as relevant, of which the following six are essential for registration of nanoforms (priority properties): chemical composition, crystallinity, particle size, particle shape, chemical nature of the surface (“surface chemistry”), and specific surface area (SSA). A key role is the reliable, reproduceable and traceable character of the data of these priority properties.
In this context, we want to discuss which ‘analytical’ information is exactly required to fulfill these conditions. Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray Photoelectron Spectroscopy (XPS) were chosen as the most popular surface analytical methods. Both methods allow a detailed understanding of the surface chemistry with an information depth below ten nanometers. As a rather bulk method for the analysis of nanoforms, Electron Probe Microanalysis (EPMA) in the version with energy dispersive X-ray spectroscopy (EDS) is considered for the quick identification of the main chemical elements present in the sample. Furthermore, Scanning Electron Microscopy (SEM) results are discussed which provide results on particle size and shape. Thus, four of the six priority properties can be obtained with these methods.
T2 - Nanosafe 2020
CY - Online meeting
DA - 17.11.2020
KW - Risk assessment
KW - Nanomaterials
KW - Standardization
KW - Regulation
PY - 2020
AN - OPUS4-51612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Zaghdoudi, M.
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
ED - Altenbach, H.
ED - Hitzler, L.
ED - Johlitz, M.
ED - Merkel, M.
ED - Öchsner, A.
T1 - Analysis of Heterogeneous Ageing of HNBR O-Rings
N2 - Abstract Hydrogenated nitrile butadiene rubber (HNBR) elastomer was thermo-oxidatively aged at different temperatures up to 150 °C. Fourier transform infrared spectroscopy (FTIR), compression stress relaxation (CSR) and international rubber hardness degree (IRHD) microhardness were used to characterise the chemo-mechanical changes of HNBR O-rings during thermo-oxidative ageing. FTIR shows the development of carbonyl, methyl and ester groups but the nitrile content was not affected by ageing. The effect of sample geometry during CSR was investigated. CSR data were converted through integrated kinetic laws. The conversion has proven its sensibility to detect heterogeneous ageing. This was confirmed by the IRHD measure-ments across the section of O-rings. The influence of compression during ageing was assessed through IRHD measurements across the section of compressed and uncom-pressed aged O-rings. The DLO effect was more pronounced in compressed O-rings. By applying the model of Wise et al., theoretical IRHD and oxidation profiles were determined on the basis of IRHD experimental data of compressed O-rings. Good agreements between the experimental and the theoretical IRHD profiles in the core region were obtained. However, near the edge, the theoretical IRHD values were overestimated.
KW - Ageing
KW - Rubber seals
KW - Stress relaxation
KW - Modelling
PY - 2024
SN - 978-3-031-49042-2
DO - https://doi.org/10.1007/978-3-031-49043-9
SN - 1869-8433
SP - 331
EP - 348
PB - Springer Nature
CY - Cham, Switzerland
AN - OPUS4-59769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sordello, F.
A1 - Prozzi, M.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
A1 - Pellegrino, F.
T1 - Increasing the HER efficiency of photodeposited metal nanoparticles over TiO2 using controlled periodic illumination
N2 - Although the use of noble metal catalysts can increase the efficiency of hydrogen evolution reaction, the process is still limited by the characteristics of the metal-hydrogen (M−H) bond, which can be too strong or too weak, depending on the metal employed. Studies revealed that the hydrogen affinity for the metal surface (i.e. H absorption/desorption) is regulated also by the potential at the metal nanoparticles. Through controlled periodic illumination (CPI) of a series of metal/TiO2 suspensions, here we demonstrated that an increase of the HER efficiency is possible for those photodeposited metals which have a Tafel slope below 125 mV. Two possible explanations are here reported, in both of them the M−H interaction and the metal covering level play a prominent role, which also depend on the prevailing HER mechanism (Volmer-Heyrovsky or Volmer-Tafel).
KW - Controlled periodic illumination
KW - Hydrogen evolution reaction
KW - Titanium dioxide
KW - Photoreforming
KW - Volcano plot
KW - Sabatier
KW - Nanoparticles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589875
DO - https://doi.org/10.1016/j.jcat.2023.115215
VL - 429
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-58987
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Faghani, A.
A1 - Gholami, M. F.
A1 - Trunk, M.
A1 - Müller, J.
A1 - Pachfule, P.
A1 - Vogl, S.
A1 - Donskyi, Ievgen
A1 - Li, M.
A1 - Nickl, Philip
A1 - Shao, J.
A1 - Huang, M. R. S.
A1 - Unger, Wolfgang
A1 - Arenal, R.
A1 - Koch, C. T.
A1 - Paulus, B.
A1 - Rabe, J. P.
A1 - Thomas, A.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Metal-Assisted and Solvent-Mediated Synthesis of Two-Dimensional Triazine Structures on Gram Scale
N2 - Covalent triazine frameworks are an emerging material class that have shown promising performance for a range of applications. In this work, we report on a metal-assisted and solvent-mediated reaction between calcium carbide and cyanuric chloride, as cheap and commercially available precursors, to synthesize two-dimensional triazine structures (2DTSs). The reaction between the solvent, dimethylformamide, and cyanuric chloride was promoted by calcium carbide and resulted in dimethylamino-s-triazine intermediates, which in turn undergo nucleophilic substitutions. This reaction was directed into two dimensions by calcium ions derived from calcium carbide and induced the formation of 2DTSs. The role of calcium ions to direct the two-dimensionality of the final structure was simulated using DFT and further proven by synthesizing molecular intermediates. The water content of the reaction medium was found to be a crucial factor that affected the structure of the products dramatically. While 2DTSs were obtained under anhydrous conditions, a mixture of graphitic material/2DTSs or only graphitic material (GM) was obtained in aqueous solutions. Due to the straightforward and gram-scale synthesis of 2DTSs, as well as their photothermal and photodynamic properties, they are promising materials for a wide range of future applications, including bacteria and virus incapacitation.
KW - XPS
KW - Triazine
KW - 2D
PY - 2020
DO - https://doi.org/10.1021/jacs.0c02399
VL - 142
IS - 30
SP - 12976
EP - 12986
PB - ACS American Chemical Society
AN - OPUS4-51203
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Terborg, R.
A1 - Hodoroaba, Vasile-Dan
T1 - Determination of Thin Film Thickness and Composition using Energy Dispersive EPMA
N2 - Electron Probe Microanalysis (EPMA) provides a non-destructive approach in the dedicated thin film analysis mode with the commercial StrataGem software. Recently, the open-source programme BadgerFilm by Moy and Fournelle became available. Similarly to StrataGem, it is based on the algorithm of Pouchou and Pichoir and needs intensity ratios of the unknown sample and standards (k-values). We have evaluated the k-values measured for the FeNi and SiGe film systems using the BadgerFilm software package and compared the thickness and composition with the results obtained with the established StrataGem software and other reference methods. The thicknesses of the SiGe films obtained by the BadgerFilm software agree within 20% with the StrataGem and TEM results; the elemental compositions BadgerFilm-StrataGEM agree within 2% with one exception (9%).
T2 - Microscopy and Microanalysis 2022
CY - Portland, OR, USA
DA - 31.07.2022
KW - Thin films
KW - Thickness
KW - Elemental composition
KW - FeNi
KW - SiGe
KW - BadgerFilm
KW - Electron Probe Microanalysis (EPMA)
PY - 2022
AN - OPUS4-55522
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Morphological Characterization and Chemical Identification of TiO2 Nanoparticles Doped with Ultrafine Metal Particles for Enhanced Photocatalytical Activity
N2 - Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy (SEM) coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, Au, Rh, Pd) and metal concentrations are discussed.
T2 - Microscopy and Microanalysis 2022
CY - Portland, OR, USA
DA - 31.07.2022
KW - Nanoparticles
KW - Me-TiO2
KW - Photocatalysis
KW - Morpho-chemical characterization
KW - Shape
KW - SEM/EDS
PY - 2022
AN - OPUS4-55541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beckmann, Jörg
T1 - Photolytically and Thermally Initiated Destruction on the Stability of (Ultra)High Molecular Polyethylene
N2 - THz and mid IR spectroscopy of high-molecular PE (HMW) and ultra high-molecular PE (UHMW) reveals modifications of the molecular structure. Characteristic absorption bands are changed if the two materials are exposed by γ-Co60 radiation up to 600 kGy and subsequently stored at an annealing temperature of 398 K until for 729 days. UHMW-PE and HMW-PE behave differently during the ageing process because of their molecular weight and inherent structure distinctions. The spectroscopic data offer characteristic absorption bands, which have been used to describe the complete ageing process in more detail. For instance, the integral absorption in the B1u THz-region can be used to describe quantitatively the reduction of crystallinity. The formation of trans vinylene unsaturation and the decay of vinyl during ageing can be observed in detail in the mid IR range.
T2 - 9th International Workshop on Terahertz Technology and Applications
CY - Kaiserslautern, Germany
DA - 03.03.2020
KW - Degradation
KW - MID IR Spectroscopy
PY - 2020
AN - OPUS4-50555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drobne, D.
A1 - Ciornii, Dmitri
A1 - Hodoroaba, Vasile-Dan
A1 - Bohmer, N.
A1 - Novak, S.
A1 - Kranjc, E.
A1 - Kononenko, V.
A1 - Reuther, R.
T1 - Knowledge, Information, and Data Readiness Levels (KaRLs) for Risk Assessment, Communication, and Governance of Nano-, New, and Other Advanced Materials
N2 - The obvious benefits derived from the increasing use of engineered nano-, new, and advanced materials and associated products have to be weighed out by a governance process against their possible risks. Differences in risk perception (beliefs about potential harm) among stakeholders, in particular nonscientists, and low transparency of the underlying decision processes can lead to a lack of support and acceptance of nano-, new, and other advanced material enabled products. To integrate scientific outcomes with stakeholders needs, this work develops a new approach comprising a nine-level, stepwise categorization and guidance system entitled “Knowledge, Information, and Data Readiness Levels” (KaRLs), analogous to the NASA Technology Readiness Levels. The KaRL system assesses the type, extent, and usability of the available data, information, and knowledge and integrates the participation of relevant and interested stakeholders in a cocreation/codesign process to improve current risk assessment, communication, and governance. The novelty of the new system is to communicate and share all available and relevant elements on material related risks in a user/stakeholder-friendly, transparent, flexible, and holistic way and so stimulate reflection, awareness, communication, and a deeper understanding that ultimately enables the discursive process that is needed for the sustainable risk governance of new materials.
KW - Risk asessment
KW - Advanced materials
KW - TRL
KW - Governance
KW - Data readiness level
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575344
DO - https://doi.org/10.1002/gch2.202200211
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-57534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rühle, Bastian
A1 - Hodoroaba, Vasile-Dan
T1 - Towards Automated Electron Microscopy Image Segmentation for Nanoparticles of Complex Shape by Convolutional Neural Networks
N2 - In this contribution different ways are explored with the aim to generate suitable training data for ‘non-ideal’ samples using various approaches, e.g., computer-generated images or unsupervised learning algorithms such as generative adversarial networks (GANs). We used these data to train simple CNNs to produce segmentation masks of SEM images and tested the trained networks on real SEM images of complex nanoparticle samples. The novel use of CNN for the automated analysis of the size of nanoparticles of complex shape and with a high degree of agglomeration has proved to be a promising tool for the evaluation of particle size distribution on a large number of constituent particles. Further development and validation of the preliminary model, respectively larger training and validation data sets are necessary.
KW - Nanoparticles
KW - Convolutional neural networks
KW - Image segmentation
KW - Electron microscopy
KW - Automatisation
PY - 2020
DO - https://doi.org/10.1017/S1431927620017262
VL - 26
IS - S2
SP - 1188
EP - 1189
PB - Cambridge University Press
CY - Cambridge, UK
AN - OPUS4-51773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Burr, L.
A1 - Schmid, D.
A1 - Hodoroaba, Vasile-Dan
T1 - Towards a method for quantitative evaluation of nanoparticle from suspensions via microarray printing and SEM analysis
N2 - As part of the development of a library of accurate and efficient methods for measurement of nanoparticle properties, we develop and optimize a method for the efficient analysis of nanoparticle size distribution from suspensions via microprinting and digital analysis of electron microscopy (SEM and TEM) images, with the ultimate aim of automated quantitative concentration analysis (calculated from drop volume). A series of different nanoparticle suspensions (gold, latex, and SiO2 in varying sizes and concentrations) were printed onto TEM grids in a 4 x 4 array in the concentration range 7x10^8 to 1x10^11 nanoparticles/mL and imaged with SEM. Concentrations and printing conditions (temperature, relative humidity) were varied in order to minimize the coffee-ring effect.
KW - Nanoparticles
KW - Particle size distribution
KW - Electron microscopy
KW - Microarray printing
KW - Sample preparation
KW - Nanoparticle concentration
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528455
DO - https://doi.org/10.1088/1742-6596/1953/1/012002
VL - 1953
SP - 012002
PB - IOP Publishing
AN - OPUS4-52845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Crouzier, L.
A1 - Feltin, N.
A1 - Delvallée, A.
A1 - Pellegrino, Francesco
A1 - Maurino, V.
A1 - Cios, Grzegorz
A1 - Tokarski, T.
A1 - Salzmann, Christoph
A1 - Deumer, J.
A1 - Gollwitzer, C.
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative analysis of the dimensional properties of bipyramidal titania nanoparticles by complementing electron microscopy with other methods
N2 - In this paper, the accurate determination of the size and size distribution of bipyramidal anatase nanoparticles (NPs) after deposition as single particles on a silicon substrate by correlative Scanning Electron Microscopy (SEM) with Atomic Force Microscopy (AFM) analysis is described as a new measurement procedure for metrological purposes. The knowledge of the exact orientation of the NPs is a crucial step in extracting the real 3D dimensions of the particles. Two approaches are proposed to determine the geometrical orientation of individual nano‐bipyramides: (i) AFM profiling along the long bipyramid axis and (ii) stage tilting followed by SEM imaging. Furthermore, a recently developed method, Transmission Kikuchi Diffraction (TKD), which needs preparation of the crystalline NPs on electron‐transparent substrates such as TEM grids, has been tested with respect to its capability of identifying the geometrical orientation of the individual NPs. With the NPs prepared homogeneously on a TEM grid, the transmission mode in a SEM, i.e., STEM‐in‐SEM (or T‐SEM), can be also applied to extract accurate projection dimensions of the nanoparticles from the same sample area as that analysed by SEM, TKD and possibly AFM. Finally, Small Angle X‐ray Scattering (SAXS) can be used as an ensemble technique able to measure the NPs in liquid suspension and, with ab‐initio knowledge of the NP shape from the descriptive imaging techniques, to provide traceable NP size distribution and particle concentration.
KW - Nanoparticles
KW - Complex-shape
KW - Bipyramid
KW - Electron microscopy
KW - AFM
KW - Size measurements
KW - TKD
KW - STEM-in-SEM
KW - SAXS
KW - Nanoparticle concentration
KW - Correlative analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539888
DO - https://doi.org/10.3390/nano11123359
SN - 2079-4991
VL - 11
IS - 12
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-53988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kovacevic, E.
A1 - Strunskus, T.
A1 - Santhosh, N. M.
A1 - Zavasnik, Z.
A1 - Unger, Wolfgang
A1 - Sauvage, T.
A1 - Ammar, M.-R.
A1 - Cvelbar, U.
A1 - Berndt, J.
T1 - Thermal stability studies of plasma deposited hydrogenated carbon nitride nanostructures
N2 - Thermally stable carbon nitride nanostructures have potential applications in surface coatings and automotive fields. In this work, hydrogenated nitrogen-rich carbon nitride nanoparticles have been synthesised via low-pressure low-power plasma vapour deposition technique from methane/Nitrogen gas mixture in a dry process. Thermal stability of the initially prepared hydrogenated carbon Nitride structures has been analysed by near-edge X-ray absorption fine-structure spectroscopy (NEXAFS, insitu), Raman spectroscopy, scanning and transmission electron microscopy and nuclear reaction Analysis (NRA). Thermal studies reveal the excellent stability of the material and nitrogen-rich characteristics (N/C ratio 0.5e0.2 ± 0.01). The obtained results suggest transformation of sp3-rich as-deposited carbon Nitride into sp2-carbon phase with more graphitic features upon thermal annealing. Such in-situ thermal studies of plasma deposited carbon nitrides confirm the conversion of sp3-rich phase to sp2-rich carbon phase at the critical temperature (about 450 K), without a huge loss in nitrogen content. The analysis revealed that the material is a stable plasma deposit after this critical temperature up to >1100 K. Additionally, super hydrophilic carbon nitride nanostructure transforms into a hydrophobic surface after thermal annealing.
These thermally stable hydrophobic carbon nitride nanoparticles could be used as a promising material for the hydrophobic coatings for various applications, especially for harsh conditions.
KW - Carbon nanoparticles
KW - Hydrogenated nanostructures
KW - Plasma deposition
KW - NEXAFS
KW - Thermal annealing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536163
DO - https://doi.org/10.1016/j.carbon.2021.08.008
SN - 0008-6223
VL - 184
SP - 82
EP - 90
PB - Elsevier Ltd.
AN - OPUS4-53616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, Francesco
A1 - Ortel, Erik
A1 - Mielke, Johannes
A1 - Schmidt, R.
A1 - Maurino, V.
A1 - Hodoroaba, Vasile-Dan
T1 - Customizing New Titanium Dioxide Nanoparticles with Controlled Particle Size and Shape Distribution: A Feasibility Study Toward Reference Materials for Quality Assurance of Nonspherical Nanoparticle Characterization
N2 - An overview is given on the synthesis of TiO2 nanoparticles with well-defined nonspherical shapes (platelet like, bipyramidal, and elongated), with the focus on controlled, reproducible synthesis, as a key requirement for the production of reference materials with homogeneous and stable properties. Particularly with regard to the nanoparticle shapes, there is a high need of certified materials,
solely one material of this type being commercially available since a few months (elongated TiO2). Further, measurement approaches with electron microscopy as the golden method to tackle the nanoparticle shape are developed to determine accurately the size and shape distribution for such nonspherical particles. A prerequisite for accurate and easy (i.e., automated) image analysis is the sample preparation, which ideally must ensure a deposition of the nanoparticles from liquid suspension onto a substrate such that the particles do not overlap, are solvent-free, and have a high deposition density. Challenges in the Synthesis of perfectly monodispersed and solvent-free TiO2 nanoparticles of platelet and acicular shapes are highlighted as well as successful measurement approaches on how to extract from 2D projection electron micrographs the most accurate spatial information, that is, true 3D size, for example, of the bipyramidal nanoparticles with different geometrical orientations on a substrate.
KW - Nanoparticles
KW - Titanium dioxide
KW - Reference materials
KW - Standardisation
KW - Particle size and shape distribution
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538849
DO - https://doi.org/10.1002/adem.202101347
VL - 24
IS - 6
SP - 1
EP - 10
PB - Wiley-VCH
AN - OPUS4-53884
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dhamo, Lorena
A1 - Carulli, F.
A1 - Nickl, Philip
A1 - Wegner, Karl David
A1 - Hodoroaba, Vasile-Dan
A1 - Würth, Christian
A1 - Brovelli, S.
A1 - Resch-Genger, Ute
T1 - Efficient luminescent solar concentrators based on environmentally friendly Cd-free ternary AIS/ZnS quantum dots
N2 - Luminescent solar concentrators (LSC) allow to obtain renewable energy from building integrated photovoltaic systems. As promising efficient and long-term stable LSC fluorophores semiconductor nanocrystals like Quantum dots (QDs) with size and composition tunable optoelectronic properties have recently emerged. The most popular II/VI or IV/VI semiconductor QDs contain, however, potentially hazardous cadmium or lead ions, which is a bottleneck for commercial applications. A simple aqueous based, microwaveassisted synthesis for environmentally friendly and highly emissive AgInS2/ ZnS QDs is developed using 3-mercaptopropionic acid (MPA) and glutathione (GSH) and their incorporation into polylaurylmethacrylate (PLMA) polymer slabs integrable in LSC devices (10.4 × 10.4 × 0.2 cm3, G = 12.98).
With this simple approach, optical power efficiencies (OPE) of 3.8% and 3.6% and optical quantum efficiencies (OQE) of 24.1% and 27.4% are obtained, which are among the highest values yet reported.
KW - Solar energy
KW - Solar concentrator
KW - Quantum dots
KW - Advanced material
KW - Quantum yield
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529735
DO - https://doi.org/10.1002/adom.202100587
SN - 2195-1071
SN - 0935-9648
VL - 9
IS - 17
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-52973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Data quality for Nanorisk Governance
N2 - Nanomaterials bring various benefits and have become a part of our daily lives. However, the risks emerging from nanotechnology need to be minimized and controlled at the regulatory level and therefore, there is a need for nanorisk governance. One of the prerequisites for successful nanorisk governance is the availability of high-quality data on nanomaterials and their impact with the human body and the environment. In recent decades, a countless number of publications and studies on nanomaterials and their properties have been produced due to the fast development of nanotechnology. Despite such a vast amount of data and information, there are certain knowledge gaps hindering an efficient nanorisk governance process. Knowing the state of the available data and information is an important requirement for any decision maker in dealing with risks. In the specific case of nanotechnology, where most of the risks are complex, ambiguous, and uncertain in nature, it is essential to obtain complete data and metadata, to fill knowledge gaps, and to transform the available knowledge into functional knowledge. This can become possible using a novel approach developed within the NANORIGO project (Grant agreement No. 814530) – the Knowledge Readiness Level (KaRL). In analogy to NASA’s Technology Readiness Levels (TRLs), we define KaRLs as a categorization system of data, information, and knowledge which enables transformation of data and information into functional knowledge for nanorisk governance. Our approach goes beyond the technical curation of data and metadata and involves quality and completeness filters, regulatory compliance requirements, nanorisk-related tools, and most importantly, human input (inclusion of all stakeholder groups). With the KaRL approach we also address key issues in nanotechnology such as societal and ethical concerns, circular economies and sustainability, the Green Deal, and the traceability of data, knowledge, and decisions. The KaRL approach could be used for nanorisk governance by a nanorisk governance council (NRGC), which is currently under development by three EU projects (NANORIGO, GOV4NANO, and RISKGONE).
T2 - Nanosafety Training School: From Basic Science To Risk Governance
CY - Online meeting
DA - 20.06.2021
KW - Data
KW - Knowledge
KW - Risk Governance
KW - Knowledge Readiness Level
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529255
AN - OPUS4-52925
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Knowledge Readiness for Nanorisk Governance
N2 - Nanomaterials bring various benefits and have become a part of our daily lives. However, the risks emerging from nanotechnology need to be minimized and controlled at the regulatory level and therefore, there is a need for nanorisk governance. One of the prerequisites for successful nanorisk governance is the availability of high-quality data on nanomaterials and their impact with the human body and the environment. In recent decades, a countless number of publications and studies on nanomaterials and their properties have been produced due to the fast development of nanotechnology. Despite such a vast amount of data and information, there are certain knowledge gaps hindering an efficient nanorisk governance process. Knowing the state of the available data and information is an important requirement for any decision maker in dealing with risks. In the specific case of nanotechnology, where most of the risks are complex, ambiguous, and uncertain in nature, it is essential to obtain complete data and metadata, to fill knowledge gaps, and to transform the available knowledge into functional knowledge. This can become possible using a novel approach developed within the NANORIGO project (Grant agreement No. 814530) – the Knowledge Readiness Level (KaRL). In analogy to NASA’s Technology Readiness Levels (TRLs), we define KaRLs as a categorization system of data, information, and knowledge which enables transformation of data and information into functional knowledge for nanorisk governance. Our approach goes beyond the technical curation of data and metadata and involves quality and completeness filters, regulatory compliance requirements, nanorisk-related tools, and most importantly, human input (inclusion of all stakeholder groups). With the KaRL approach we also address key issues in nanotechnology such as societal and ethical concerns, circular economies and sustainability, the Green Deal, and the traceability of data, knowledge, and decisions. The KaRL approach could be used for nanorisk governance by a nanorisk governance council (NRGC), which is currently under development by three EU projects (NANORIGO, GOV4NANO, and RISKGONE).
T2 - Gov4Nano: data management core group
CY - Online meeting
DA - 05.07.2021
KW - Data Management
KW - Knowledge Readiness Level
KW - Nanorisk Governance
KW - Participatory Approach
KW - Sustainability
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529264
AN - OPUS4-52926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Towards 3D understanding of non spherical nanoparticles by Transmission Kikuchi Diffraction (TKD) for improved particle size distribution by electron microscopy
N2 - In this paper one refined approach is applied to determine the exact orientation of bipyramidal TiO2 nanoparticles prepared with good dispersion as almost isolated particles on a carbon TEM grid. The advantages of the recently developed high-throughput Transmission Kikuchi Diffraction (TKD) are used to identify quickly and reliably the geometrical orientation of the crystalline TiO2 nanoparticle bipyramids (anatase) on a statistically relevant number of particles.
T2 - Microscopy and Microanalysis 2020
CY - Online meeting
DA - 03.08.2020
KW - Nanoparticles
KW - Transmission Kikuchi Diffraction (TKD)
KW - TiO2
KW - 3D
KW - Electron microscopy
PY - 2020
AN - OPUS4-51113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Hodoroaba, Vasile-Dan
A1 - Kraehnert, R.
A1 - Hertwig, Andreas
T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films
N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing.
We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP).
KW - Electrochemical catalysts
KW - Mixed metal oxide
KW - Multi-sample analysis
KW - Spectroscopic ellipsometry
KW - Thin mesoporous films
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026
DO - https://doi.org/10.1515/aot-2022-0007
SN - 2192-8584
SN - 2192-8576
VL - 11
IS - 3-4 (Topical issue: Ellipsometry)
SP - 137
EP - 147
PB - De Gruyter
CY - Berlin
AN - OPUS4-55102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brüngel, R.
A1 - Rückert, J.
A1 - Müller, P.
A1 - Babick, F.
A1 - Friedrich, C. M.
A1 - Ghanem, A.
A1 - Hodoroaba, Vasile-Dan
A1 - Mech, A.
A1 - Weigel, S.
A1 - Wohlleben, W.
A1 - Rauscher, H.
T1 - NanoDefiner Framework and e-Tool Revisited According to the European Commission’s Nanomaterial Definition 2022/C 229/01
N2 - The new recommended definition of a nanomaterial, 2022/C 229/01, adopted by the European Commission in 2022, will have a considerable impact on European Union legislation addressing chemicals, and therefore tools to implement this new definition are urgently needed. The updated NanoDefiner framework and its e-tool implementation presented here are such instruments, which help stakeholders to find out in a straightforward way whether a material is a nanomaterial or not. They are two major outcomes of the NanoDefine project, which is explicitly referred to in the new definition. This work revisits the framework and e-tool, and elaborates necessary adjustments to make these outcomes applicable for the updated recommendation. A broad set of case studies on representative materials confirms the validity of these adjustments. To further foster the sustainability and applicability of the framework and e-tool, measures for the FAIRification of expert knowledge within the e-tool’s knowledge base are elaborated as well. The updated framework and e-tool are now ready to be used in line with the updated recommendation. The presented approach may serve as an example for reviewing existing guidance and tools developed for the previous definition 2011/696/EU, particularly those adopting NanoDefine project outcomes.
KW - Nanomaterial definition
KW - Nanomaterial categorisation
KW - Nanomaterial regulation
KW - Nanomaterial legislation
KW - Decision support
KW - FAIRification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571618
DO - https://doi.org/10.3390/nano13060990
SN - 2079-4991
VL - 13
IS - 6 - Special Issue "Identification and Quantification of Nanomaterials"
SP - 1
EP - 16
PB - MDPI
CY - Basel, CH
AN - OPUS4-57161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Understanding the recovery behaviour and the degradative processes of EPDM during ageing
N2 - Recovery is an important measure for seal applications representing to which extent the elastomer regains its initial shape after deformation and release of an applied force. Compression set (CS) indicates the degree of recovery. Ethylene propylene diene rubber (EPDM) was aged at 75 ◦C, 100 ◦C, 125 ◦C and 150 ◦C for different ageing times up to five years and compression set measurements were performed at different times after disassembly and after additional tempering. Short- and long-term recovery up to one year after release for samples aged at 125 ◦C and 150 ◦C was also studied. To assess the curvature in the Arrhenius diagram that may occur due to non-sufficiently aged specimens, a degradation-rate based model was fitted to the CS data after tempering. For each ageing temperature, two decay fit functions were proposed, each with an activation energy and a corresponding degradative process. The influence of ageing on the leak-tightness after fast small partial release is investigated and estimated through the analysis of the shift factors from time temperature superposition (TTS) of CS measurements at different times after disassembly. Shift factors of CS measurement after 1 s and after additional tempering are in good agreement.
KW - Compression set
KW - Ageing
KW - Recovery
KW - Degradative processes
KW - Leakage rate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573699
DO - https://doi.org/10.1016/j.polymertesting.2023.107987
SN - 0142-9418
VL - 121
SP - 107987
PB - Elsevier Ltd.
AN - OPUS4-57369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Bartczak, D.
A1 - Hodoroaba, Vasile-Dan
T1 - Report on the development and validation of the reference material candidates with non-spherical shape, non-monodisperse size distributions and accurate nanoparticle concentrations
N2 - One aim of the EMPIR nPSize project 17NRM04 was to develop and validate three classes of candidate reference (test) materials (RTMs), with i) well-defined non-spherical shape, ii) relatively high polydispersity index, and iii) accurate particle concentrations.
To fulfil the requirements of the project, 11 different types of materials were prepared. Following the initial assessment of the materials suitability, nPSize5_PT_UNITO, nPSize6_AC_UNITO and nPSize7_GN_CEA materials were found unsuitable for the project, due to various reasons. PT material was deemed unsuitable due to its predominantly agglomerated nature. AC material contained relatively high amount of impurities (other particle forms). GN material was found too heterogeneous in both the length and width for the purpose of the project. The remaining 8 candidate RTMs were assessed for their homogeneity and stability and used for successful delivery of the associated activities within the nPSize project.
KW - Nanoparticles
KW - Particle size distribution
KW - Reference materials
KW - Non-spherical shape
KW - EMPIR nPSize
KW - Electron microscopy
KW - AFM
KW - SAXS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556015
DO - https://doi.org/10.5281/zenodo.7016466
SP - 1
EP - 22
PB - Zenodo
CY - Geneva
AN - OPUS4-55601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hesse, R.
A1 - Denecke, R.
A1 - Radnik, Jörg
T1 - Testing and validating the improved estimation of the spectrometer-transmission function with UNIFIT 2022
N2 - Recent developments of X-ray photoelectron spectroscopy using excitation energies different from the usual lab-sources Mg Kα and Al Kα, thus covering larger and different kinetic energy ranges, require more flexible approaches for determining the transmission function than the well-established ones using reference spectra. Therefore, the approach using quantified peak areas (QPA) was refined allowing a more precise estimation of the transmission function. This refinement was tested by comparing the results obtained with the new version with former calculations. Furthermore, the obtained transmission function was validated by comparing the results with a transmission function using the reference spectrum of polyethylene. Additionally, an ionic liquid was used as reference for estimating the transmission function at the energy resolved HE-SGM beamline at BESSY II. Comparison between the measured and stoichiometric composition shows that a transmission function was determined, which allows a reasonable quantification.
KW - XPS
KW - Quantification
KW - Software UNIFIT 2022
KW - Synchrotron radiation
KW - Transmission function IERF
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551671
DO - https://doi.org/10.1002/sia.7131
SN - 0142-2421
SP - 1
EP - 7
PB - Wiley-VCH
AN - OPUS4-55167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Oxidative ageing of elastomers: Experiment and modelling
N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of 125∘C and 150∘C. To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments.
KW - Compression stress relaxation
KW - Compression set
KW - IRHD microhardness
KW - Modelling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545910
DO - https://doi.org/10.1007/s00161-022-01093-9
SN - 1432-0959
SP - 1
EP - 9
PB - Springer
CY - Berlin
AN - OPUS4-54591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Unger, Wolfgang
A1 - Wirth, Thomas
A1 - Hodoroaba, Vasile-Dan
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Auger electron spectroscopy
N2 - An introduction in the application of Auger Electron Spectroscopy to surface chemical analysis of nanoparticles is given. Auger Electron Spectroscopy is a mature method in the field of surface chemical analysis. The chapter addresses the physical basis of the method, the principal design of recent instruments together with modes of operation and options for the presentation of spectra, as well as different approaches for qualitative (including identification of chemical species) and quantitative surface analysis of elements. An application paragraph on surface chemical analysis of nanoparticles by AES or SAM introduces the different measurement approaches and sample preparation strategies applied by analysts. The analysis of nanoparticle ensembles, the so-called selected point analysis where a narrow primary electron beam is centered on an individual nanoparticle, and chemical mapping of individual nanoparticles (or a line scan across) are addressed. Existing literature is reviewed and informative case studies presented. Limitations and pitfalls in the application of AES in surface chemical analysis of nanoparticles are also addressed.
KW - Auger Electron Spectroscopy
KW - Surface chemical analysis
KW - Imaging surface chemical analysis
KW - Nanoparticles
KW - Nanotechnology
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00020-1
SP - 373
EP - 395
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50119
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Mast, J.
A1 - Verleysen, E.
A1 - Hodoroaba, Vasile-Dan
A1 - Kaegi, R.
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Characterization of nanomaterials by transmission electron microscopy - Measurement procedures
N2 - In this chapter, approaches are proposed for the descriptive and quantitative characterization of nano-objects with nanometer resolution. Measurements are based on the analysis of the characteristics of 2D projections of individual particles visualized on transmission electron micrographs.
Incorporation of spectroscopic methods (EDS and EELS) for elemental analysis of nano-objects is recommended to identify subpopulations of nano-objects in mixtures based on their chemical composition. The focus lies on the determination of physicochemical properties which are essential in a legislatory and regulatory context to define the material as a nanomaterial (NM), and to assess its safety and toxicological potential, using widely accessible equipment.
KW - Nanoparticles
KW - Sample preparation
KW - Image analysis
KW - Transmission electron microscopy
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00004-3
SP - 29
EP - 48
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Energy-dispersive X-ray spectroscopy (EDS)
N2 - As one of the widely used analytical methods for the analysis of elemental composition of solid matter, energy dispersive X-ray spectroscopy (EDS) has recently gained significant importance regarding its application to the chemical analysis of nanoparticles, especially in conjunction with the use of a scanning electron microscope (SEM) and the use of the transmission operation mode of SEM (STEM-in-SEM). This development was mainly driven by the technological progress with highly sensitive EDS detectors, such that individual nanoparticles can be quickly inspected with EDS at a SEM. Qualitative information on elemental composition with about 10 nm spatial resolution can be achieved complementary to the high-resolution information of the sample surface morphology within the same scanned area as provided by the electron microscope. Representative examples with successful EDS analysis on nanoparticles are presented, but also limitations of the method are described.
KW - EDS
KW - EPMA
KW - X-rays
KW - SEM/EDS
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00021-3
SP - 397
EP - 417
PB - Elsevier
CY - Amsterdam
AN - OPUS4-49991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Clifford, C.
A1 - Stintz, M.
A1 - Hodoroaba, Vasile-Dan
A1 - Unger, Wolfgang
A1 - Fujimoto, T.
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - International standards in nanotechnologies
N2 - This chapter provides an overview of what standards are, why they are important, and how they are developed. There is a focus on the work of standards committees relevant to nanotechnology measurement and characterization with tables detailing the standards that are currently available for a large number of different techniques, materials, and applications at the nanoscale.
KW - Standards
KW - Nanotechnology
KW - Reproducibility
KW - ISO
KW - CEN
KW - VAMAS
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00026-2
SP - 511
EP - 525
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
A1 - Unger, Wolfgang
A1 - Shard, A. G.
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Conclusions and perspectives
N2 - This chapter briefly summarizes the methods selected within this book for the characterization of nanoparticles with regard to commonly accessible properties: nanoparticle size and size distribution, shape, surface area, surface charge, aggregation state, structure, chemical composition, surface chemistry, and nanoparticle number concentration. Current progress of measurement and analysis, as far as possible according to standard operation procedures, has been the focus of this work. A number of new and less commonly used methods have not been covered, and we outline some of these in this chapter. Future challenges such as automated measurement and analysis, read-across approaches for the prediction of properties, knowledge of measurement uncertainties, the need for certified reference materials, and the necessity to complement measurements methods to obtain more reliable results are covered, and the unmet measurement requirements for real-world nanoparticles are described.
KW - Physicochemical characterization
KW - Standard operation procedures
KW - Data correlation
KW - Method development
KW - Trends
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00006-7
SP - 527
EP - 534
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Shard, A. G.
A1 - Hodoroaba, Vasile-Dan
A1 - Unger, Wolfgang
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Introduction
N2 - The purpose of this book is to provide a comprehensive collection of analytical methods that are commonly used to measure nanoparticles, providing information on one, or more, property of importance. The chapters provide up-to-date information and guidance on the use of these techniques, detailing the manner in which they may be reliably employed. Within this chapter, we detail the rationale and context of the whole book, which is driven by the observation of a low level of reproducibility in nanoparticle research. The aim of the book is to encourage awareness of both the strengths and weaknesses of the various methods used to measure nanoparticles and raise awareness of the range of methods that are available. The editors of the book have, for many years, been engaged in European projects and standardization activities concerned with nanoparticle analysis and have identified authors who are experts in the various methods included within the book. This has produced a book that can be used as a definitive guide to current best practice in nanoparticle measurement.
KW - Nanoparticles
KW - Size distribution
KW - Shape
KW - Chemistry
KW - Coating
KW - Concentration
KW - Standards
KW - Charge
KW - Characterisation
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00001-8
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis
N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing project "FIB sample processing for TEM" is presented in detail.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 48th Steering Committee Meeting
CY - New Delhi, India
DA - 9.10.2023
KW - TEM
KW - FIB
KW - EBSD
KW - Sample preparation
KW - VAMAS
KW - Standardisation
KW - Interlaboratory comparisons
PY - 2023
UR - https://www.nplindia.org/index.php/amcsnzt_2023/
AN - OPUS4-58538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Gibson, N.
A1 - Kuchenbecker, Petra
A1 - Rasmussen, K.
A1 - Hodoroaba, Vasile-Dan
A1 - Rauscher, H.
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A.G.
T1 - Volume-specific surface area by gas adsorption analysis with the BET method
N2 - This chapter first gives an introduction to the concepts of SSA and volume-specific surface area (VSSA) and an outline of the BET method. It continues with a discussion of the relationship between particle size, shape, and the VSSA, followed by an overview of instrumentation, experimental methods, and standards. Finally, sections on the use of the VSSA as a tool to identify nanomaterials and non-nanomaterials and its role in a regulatory context provide some insight on the importance of VSSA in the current Regulation of nanomaterials.
KW - Nanomaterials
KW - Volume specific surface area
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00017-1
SP - 265
EP - 293
PB - Elsevier
CY - Amsterdam
AN - OPUS4-49572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Donskyi, Ievgen
A1 - Chen, Y.
A1 - Nickl, Philip
A1 - Guday, G.
A1 - Qiao, H.
A1 - Achasi, K.
A1 - Lippitz, Andreas
A1 - Unger, Wolfgang
A1 - Böttcher, C.
A1 - Chen, W.
A1 - Adeli, M.
A1 - Haag, R.
T1 - Self-degrading graphene sheets for tumor therapy
N2 - Low biodegradability of graphene derivatives and related health risks are the main limiting factors for their in vivo biomedical applications. Here, we present the synthesis of enzyme-functionalized graphene sheets with self-degrading properties under physiological conditions and their applications in Tumor therapy. The synergistic enzyme cascade glucose oxidase and myeloperoxidase are covalently conjugated to the surface of graphene sheets and two-dimensional (2D) platforms are obtained that can produce sodium hypochlorite from glucose. The enzyme-functionalized graphene sheets with up to 289 nm average size are degraded into small pieces (≤40 nm) by incubation under physiological conditions for 24 h. Biodegradable graphene sheets are further loaded with doxorubicin and their ability for Tumor therapy is evaluated in vitro and in vivo. The laser-triggered release of doxorubicin in combination with the enzymatic activity of the functionalized graphene sheets results in a synergistic antitumor activity.
Taking advantage of their neutrophil-like activity, fast biodegradability, high photo- and chemotherapeutic effects, the novel two-dimensional nanoplatforms can be used for tumor therapeutic applications.
KW - Graphene
KW - Self-degrading
KW - Thumor therapy
KW - XPS
KW - NEXAFS
PY - 2020
DO - https://doi.org/10.1039/d0nr02159h
SP - 1
EP - 12
PB - The Royal Society of Chemistry
AN - OPUS4-50978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Friedrich, C. M.
A1 - Weigel, S.
A1 - Marvin, H.
A1 - Rauscher, H.
A1 - Wohlleben, W.
A1 - Babick, F.
A1 - Löschner, K.
A1 - Mech, A.
A1 - Brüngel, R.
A1 - Hodoroaba, Vasile-Dan
A1 - Gilliland, D.
A1 - Rasmussen, K.
A1 - Ghanem, A.
T1 - The NanoDefine Methods Manual
N2 - This document is a collection of three JRC Technical Reports that together form the “NanoDefine Methods Manual”, which has been developed within the NanoDefine project ‘Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial’, funded by the European Union’s 7th Framework Programme, under grant agreement 604347. The overall goal of the NanoDefine project was to support the implementation of the European Commission Recommendation on the definition of nanomaterial (2011/696/EU). The project has developed an integrated empirical approach, which allows identifying a material as a nano- or not a nanomaterial according to the EC Recommendation. The NanoDefine Methods Manual consists of three parts: Part 1: The NanoDefiner Framework and Tools, which covers the NanoDefiner framework, general information on measurement methods and performance criteria, and tools developed by NanoDefine such as a materials categorisation system, a decision support flow scheme and an e-tool. Part 2: Evaluation of Methods, which discusses the outcome of the evaluation of the nanomaterials characterisation methods for measuring size. Part 3: Standard Operating Procedures (SOPs), which presents the 23 Standard Operating Procedures developed within the NanoDefine project. In this combined document, these three parts are included as stand-alone reports, each having its own abstract, table of contents, page, table and figure numbering, and references.
KW - Nanomaterial
KW - Particle size distribution
KW - Nanoparticles
KW - NanoDefine
KW - Nanomaterial classification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504250
SN - 978-92-76-12335-4
DO - https://doi.org/10.2760/79490
VL - JRC117501
SP - 1
EP - 451
PB - Publications Office of the European Union
CY - Luxembourg
AN - OPUS4-50425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Mech, A.
A1 - Rauscher, H.
A1 - Rasmussen, K.
A1 - Babick, F.
A1 - Hodoroaba, Vasile-Dan
A1 - Ghanem, A.
A1 - Wohlleben, W.
A1 - Marvin, H.
A1 - Brüngel, R.
A1 - Friedrich, C. M.
A1 - Löschner, K.
A1 - Gilliland, D.
T1 - The NanoDefine Methods Manual - Part 3: Standard Operating Procedures (SOPs)
N2 - The present series of reports, the NanoDefine Methods Manual, has been developed within the NanoDefine project 'Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial'1 funded by the European Union's 7th Framework Programme, under grant agreement 604347.
In 2011 the European Commission (EC) published the recommendation (2011/696/EU) for a definition of the term 'nanomaterial'1, the EC NM Definition, as a reference to determine whether an unknown material can be considered as a 'nanomaterial' for regulatory purposes. One challenge is the development of methods that reliably identify, characterize and quantify nanomaterials (NM) both as substances and in various products and matrices.
The overall goal of NanoDefine was to support the implementation of the EC NM Definition. It can also support the implementation of any NM definition based on particle size. The project has developed an integrated approach, which allows identifying any material as a nano or non-nano material according to the EC NM Definition. NanoDefine explicitly supported the governance challenges associated with the implementation of legislation concerning nanomaterials by:
- addressing the issues on availability of suitable measuring techniques, reference materials, validated methods, acceptable to all - developing an integrated and interdisciplinary approach and a close international co-operation and networking with academia, commercial firms and standardization bodies.
Thus, the NanoDefine Methods Manual provides guidance on practical implementation of the EC NM Definition throughout the nanomaterial characterization process, and on the characterization techniques employed as well as their application range and limits. It assists the user in choosing the most appropriate measurement method(s) to identify any substance or mixture for a specific purpose, according to the EC NM Definition of a nanomaterial. The NanoDefine project also explored how to assess a material against the criteria of the definition through proxy solutions, i.e. by applying measurement techniques that indirectly determine the D50. Those findings were developed through empirically based scientific work and are included in Part 1 of this Manual. As they go beyond the text of the EC NM Definition, they may be used as practical approach to indicate whether a material is a nanomaterial or not, but keeping in mind that they should not be taken as recommendation for the implementation of the EC NM Definition in a regulatory context.
The NanoDefine Methods Manual consists of the following three parts:
Part 1: The NanoDefiner Framework and Tools
Part 2: Evaluation of Methods
Part 3: Standard Operating Procedures (SOPs)
Part 1 covers the NanoDefiner framework, general information on measurement methods and performance criteria and tools developed by NanoDefine such as a materials categorisation system, a decision support flow scheme and an e-tool.
Part 2 discusses the outcome of the evaluation of the nanomaterials characterisation methods for measuring size.
Part 3 presents the 23 Standard Operating Procedures developed within the NanoDefine project. The current document is part 3.
KW - Nanomaterial
KW - Nanoparticles
KW - Particle size distribution
KW - NanoDefine
KW - Standard Operation Procedures
KW - Nanomaterial classification
KW - SOP
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503710
SN - 978-92-76-11955-5
DO - https://doi.org/10.2760/02910
SN - 1831-9424
VL - JRC117501
SP - 1
EP - 215
PB - Publications Office of the European Union
CY - Luxembourg
AN - OPUS4-50371
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mech, A.
A1 - Wohlleben, W.
A1 - Ghanem, A.
A1 - Hodoroaba, Vasile-Dan
A1 - Weigel, S.
A1 - Babick, F.
A1 - Brüngel, R.
A1 - Friedrich, C. M.
A1 - Rasmussen, K.
A1 - Rauscher, H.
T1 - Nano or Not Nano? A Structured Approach for Identifying Nanomaterials According to the European Commission’s Definition
N2 - Identifying nanomaterials (NMs) according to European Union Legislation is challenging, as there is an enormous variety of materials, with different physico-chemical properties. The NanoDefiner Framework and its Decision Support Flow Scheme (DSFS) allow choosing the optimal method to measure the particle size distribution by matching the material properties and the performance of the particular measurement techniques. The DSFS leads to a reliable and economic decision whether a material is an NM or not based on scientific criteria and respecting regulatory requirements. The DSFS starts beyond regulatory requirements by identifying non-NMs by a proxy Approach based on their volume-specific surface area. In a second step, it identifies NMs. The DSFS is tested on real-world materials and is implemented in an e-tool. The DSFS is compared with a decision flowchart of the European Commission’s (EC) Joint Research Centre (JRC), which rigorously follows the explicit criteria of the EC NM definition with the focus on identifying NMs, and non-NMs are identified by exclusion. The two approaches build on the same scientific basis and measurement methods, but start from opposite ends: the JRC Flowchart starts by identifying NMs, whereas the NanoDefiner Framework first identifies non-NMs.
KW - Classification
KW - Definition
KW - Identification
KW - Nanomaterials
KW - Particle size
KW - Regulation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510917
DO - https://doi.org/10.1002/smll.202002228
SN - 1613-6829
SP - 2002228-1
EP - 2002228-16
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-51091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rühle, Bastian
A1 - Krumrey, Julian Frederic
A1 - Hodoroaba, Vasile-Dan
T1 - Workflow towards automated segmentation of agglomerated, non‑spherical particles from electron microscopy images using artificial neural networks
N2 - We present a workflow for obtaining fully trained artificial neural networks that can perform automatic particle segmentations of agglomerated, non-spherical nanoparticles from scanning electron microscopy images “from scratch”, without the need for large training data sets of manually annotated images. The whole process only requires about 15 minutes of hands-on time by a user and can typically be finished within less than 12 hours when training on a single graphics card (GPU). After training, SEM image analysis can be carried out by the artificial neural network within seconds. This is achieved by using unsupervised learning for most of the training dataset generation, making heavy use of generative adversarial networks and especially unpaired image-to-image translation via cycle-consistent adversarial networks. We compare the segmentation masks obtained with our suggested workflow qualitatively and quantitatively to state-of-the-art methods using various metrics. Finally, we used the segmentation masks for automatically extracting particle size distributions from the SEM images of TiO2 particles, which were in excellent agreement with particle size distributions obtained manually but could be obtained in a fraction of the time.
KW - Electron microscopy
KW - Neural networks
KW - Artificial intelligence
KW - Image segmentation
KW - Automated image analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522454
DO - https://doi.org/10.1038/s41598-021-84287-6
VL - 11
IS - 1
SP - 4942
PB - Springer Nature
AN - OPUS4-52245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Comprehensive characterization of Al-coated titania nanoparticles with electron microscopy and surface chemical analytics
N2 - The wide use of nanoforms with at least one dimension below 100 nm in our daily life requires a detailed knowledge of their physicochemical properties which are needed for risk assessment or quality control. Therefore, a comprehensive characterization of these properties was considered as relevant including: chemical composition, crystallinity, particle size, particle shape, surface chemistry, and specific surface area (SSA).
We want to discuss, how Scanning Electron Microscopy (SEM), Electron Probe Microanalysis (EPMA) in the version with energy dispersive X-ray spectroscopy (EDS), Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and X-ray Photoelectron Spectroscopy (XPS) can contribute to gain comprehensive insights into the nature of the nanoparticles. SEM results provide the particle size and shape (distribution). A quick identification of the main chemical elements present in the sample can be obtained with EDS, whereas XPS allows a more detailed chemical identification of the small nanoparticles below 20 nm or of the near-surface region of larger particles. ToF-SIMS is even much more surface-sensitive and leads to a deeper understanding of the surface chemistry of the nanoparticles. As exemplary samples, two Al-coated TiO2 samples in nanopowder form were chosen from the JRC repository, capped either with a hydrophilic or a hydrophobic organic shell.
A focus of our case study was to show, how reliable, reproducible and traceable data can be obtained. Therefore, each step in the workflow of sample investigation must be described in detail. For the most of these steps, well-established standards are available. Usually, the conditions of the particular measurements with each analysis method are saved as meta-data in the common file formats. But other factors like sample preparation and data reduction approaches may influence the result of the investigations in a significant manner and must be described often in a separate file (as a protocol) together with the data file. For sensitive materials like nanoobjects, the preparation of the sample influences the results crucially, e.g. measured as suspension or as powders. Furthermore, data reduction like selection of relevant peaks in spectra or particles in images, background subtraction, peak deconvolution, models for the quantification of the spectra must be considered in the interpretation of the results ideally with associated individual measurement uncertainties. Only a detailed description of all these factors allows to obtain a comprehensive characterization with reliable, reproduceable and traceable data. Examples of standardized procedures of measurement or on data reduction will be highlighted.
We thank for the funding from the European Unions’s Horizon 2020 for the project NanoSolveIt (grant agreement No. 814572) and for the project NANORIGO (grant agreement No. 814530).
T2 - E-MRS Spring Meeting
CY - Online meeting
DA - 31.05.2021
KW - Scanning Electron Microscopy
KW - Energy dispersive X-ray spectroscopy
KW - Time-of-Flight Secondary Ion Mass Spectrometry
KW - X-ray Photoelectron Spectroscopy
KW - Titania nanoparticles
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527486
AN - OPUS4-52748
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Knowledge Readiness Level (KaRL) approach for nanorisk governance and beyond
N2 - Regulatory decisions require reliable data and knowledge derived from this. Among stakeholders in nanotechnology, however, there is often uncertainty about the quality of data for regulatory purposes. In addition, the general public often finds itself excluded from nanoregulation and policy decisions. This creates uncertainty in the nanotechnology field and also in other branches of technology and leads to concerns among the society.
To address these issues, NANORIGO elaborates a framework to support decision making as well as data, information and knowledge sharing and use. We refer to “reliability” of data and knowledge as a degree of readiness or maturity. According to these criteria we worked out a 9-level scale in analogy to TRL (technology readiness level), the KaRL system (Knowledge, Data and Information Readiness Level). KaRL allows assessment of knowledge readiness for decision making by applying defined quality criteria for each level. It also provides guidance on how to enhance the readiness level by the help of available tools and procedures. KaRL addresses SEIN[1] principles, circular economy and thus involves the public concerns in regulation. A specialized nanorisk governance council (being under development in NANORIGO) is suggested to perform quality check of an actionable document, thus, aiding in consensus on the reliability (maturity) of knowledge for decision making. Moreover, KaRL facilitates traceability of knowledge before its use in decision making. This enables the transparency demanded by all stakeholders.
T2 - EuroNanoForum 2021
CY - Online meeting
DA - 05.05.2021
KW - Knowledge Readiness Level
KW - Nanorisk
KW - Nanomaterials
KW - Data
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524725
AN - OPUS4-52472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Baer, D. R.
A1 - Cant, D. J. H.
A1 - Castner, D. G.
A1 - Ceccone, G.
A1 - Engelhard, M. H.
A1 - Karakoti, A. S.
A1 - Müller, Anja
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Preparation of nanoparticles for surface analysis
N2 - A variety of methods used to prepare nano-objects for surface analysis are described along with information about when they might be best applied. Intrinsic properties of NPs which complicate their characterization and need to be considered when planning for surface or other analyses of NPs are identified, including challenges associated with reproducible synthesis and functionalization of the particles as well as their dynamic nature. The relevant information about the sample preparation processes, along with analysis details and data that need to be added to the collection of material provenance information is identified. Examples of protocols that have been successfully used for preparation of nano-objects for surface analysis are included in an annex.
KW - Sample preparation
KW - Nanoparticles
KW - Surface chemistry
KW - XPS
KW - Dynamic behavior
KW - Nano-object
KW - Surface analysis
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00018-3
SP - 295
EP - 347
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marcoulaki, E.
A1 - M. López de Ipina, J.
A1 - Vercauteren, S.
A1 - Bouillard, J.
A1 - Himly, M.
A1 - Lynch, I.
A1 - Witters, H.
A1 - Shandilya, N.
A1 - van Duuren-Stuurman, B.
A1 - Kunz, Valentin
A1 - Unger, Wolfgang
A1 - Hodoroaba, Vasile-Dan
A1 - Bard, D.
A1 - Evans, G.
A1 - Jensen, K. A.
A1 - Pilou, M.
A1 - Viitanen, A.-K.
A1 - Bochon, A.
A1 - Duschl, A.
A1 - Geppert, M.
A1 - Persson, K.
A1 - Votgreave, I.
A1 - Niga, P.
A1 - Gini, M.
A1 - Eleftheriadis, K.
A1 - Scalbi, S.
A1 - Caillard, B.
A1 - Arevalillo, A.
A1 - Frejafon, E.
A1 - Aguerre-Chariol, O.
A1 - Dulio, V.
T1 - Blueprint for a self-sustained European Centre for service provision in safe and sustainable innovation for nanotechnology
N2 - The coming years are expected to bring rapid changes in the nanotechnology regulatory landscape, with the establishment of a new framework for nano-risk governance, in silico approaches for characterisation and Risk assessment of nanomaterials, and novel procedures for the early identification and management of nanomaterial risks. In this context, Safe(r)-by-Design (SbD) emerges as a powerful preventive approach to support the development of safe and sustainable (SSbD) nanotechnology-based products and processes throughout the life cycle. This paper summarises the work undertaken to develop a blueprint for the deployment and operation of a permanent European Centre of collaborating laboratories and research organisations supporting safe Innovation in nanotechnologies. The proposed entity, referred to as “the Centre”, will establish a ‘one-stop shop’ for nanosafety-related services and a central contact point for addressing stakeholder questions about nanosafety. Its operation will rely on significant business, legal and market knowledge, as well as other tools developed and acquired through the EU-funded EC4SafeNano project and subsequent ongoing activities. The proposed blueprint adopts a demand-driven service update scheme to allow the necessary vigilance and flexibility to identify opportunities and adjust its activities and services in the rapidly evolving regulatory and nano risk governance landscape.
The proposed Centre will play a major role as a conduit to transfer scientific knowledge between the Research and commercial laboratories or consultants able to provide high quality nanosafety services, and the end-users of such services (e.g., industry, SMEs, consultancy firms, and regulatory authorities). The Centre will harmonise service provision, and bring novel risk assessment and management approaches, e.g. in silico methodologies, closer to practice, notably through SbD/SSbD, and decisively support safe and sustainable innovation of industrial production in the nanotechnology industry according to the European Chemicals Strategy for Sustainability.
KW - Nanotechnology
KW - European Centre
KW - Nano-safety
KW - Nanomaterials
KW - analytical service
PY - 2021
DO - https://doi.org/10.1016/j.impact.2021.100337
VL - 23
SP - 100337
PB - Elsevier B.V.
AN - OPUS4-52942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schaepe, Kaija
A1 - Jungnickel, H.
A1 - Heinrich, Thomas
A1 - Tentschert, J.
A1 - Luch, A.
A1 - Unger, Wolfgang
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Secondary ion mass spectrometry
N2 - This chapter provides an introduction in secondary ion mass spectrometry as one of the leading surface chemical analysis and imaging techniques with molecular specificity in the field of material sciences. The physical basics of the technique are explained along with a description of the typical instrumental setups and their modes of operation. The application paragraph specifically focuses on nanoparticle analysis by SIMS in terms of surface spectrometry, imaging, analysis in organic and complex media, and depth profiling.
A review of the existing literature is provided, and selected studies are showcased. Limitations and pitfalls as well as current technical developments of SIMS application in nanoparticle surface chemical analysis are equally discussed.
KW - Time-of-flight secondary ion mass spectrometry
KW - Surface chemical analysis
KW - Imaging
KW - Nanomaterials
KW - Nanoparticles
KW - Core-shell
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00025-0
SP - 481
EP - 509
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Characterization of functionalized graphene particles with comparative XPS/HAXPES investigations
N2 - The different chmemistry of graphitic nanoplatelets between the outermost surface and the bulk of the samples was investigated with comparative XPS/HAXPES measurements.
T2 - PHI User Meeting
CY - Grenoble, France
DA - 18.04.2023
KW - X-ray photoelectron spectroscopy
KW - Hard-energy X-ray photoelectron spectroscopy
KW - graphene related 2D materials
PY - 2023
AN - OPUS4-57649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chemello, Giovanni
T1 - Measurement of the morphology of graphene related 2D materials as flakes
N2 - The presentation shows the results of the mini-interlaboratory comparison focused on the measurement of the morphology of graphene oxide flakes using scanning electron microscopy. In this work, a route for the sample preparation, SEM measurement and image analysis is proposed. The results of the image analysis, performed on 200+ flakes per sample, are presented by comparing the distributions of the size and shape descriptors calculated according to two different approaches. The influences of a different SEM measurement operator, analysis approach and analysis operator on the final size and shape distributions are highlighted.
T2 - EMRS Fall 2023
CY - Warsaw, Poland
DA - 18.09.2023
KW - Graphene oxide
KW - SEM
KW - 2D flakes
KW - Image analysis
PY - 2023
AN - OPUS4-58752
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Mech, A.
A1 - Rauscher, H.
A1 - Rasmussen, K.
A1 - Babick, F.
A1 - Hodoroaba, Vasile-Dan
A1 - Ghanem, A.
A1 - Wohlleben, W.
A1 - Marvin, H.
A1 - Brüngel, R.
A1 - Friedrich, C. M.
T1 - The NanoDefine Methods Manual - Part 2: Evaluation of methods
N2 - The present series of reports, the NanoDefine Methods Manual, has been developed within the NanoDefine project 'Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial', funded by the European Union's 7th Framework Programme, under grant agreement 604347.
In 2011 the European Commission (EC) published a recommendation for a definition of the term 'nanomaterial', the EC NM Definition, as a reference to determine whether an unknown material can be considered as a 'nanomaterial' for regulatory purposes1. One challenge is the development of methods that reliably identify, characterize and quantify nanomaterials (NM) both as substances and in various products and matrices.
The overall goal of NanoDefine was to support the implementation of the EC NM Definition. It can also support the implementation of any NM definition based on particle size. The project has developed an integrated approach, which allows identifying any material as a nano- or not a nanomaterial according to the EC NM Definition. NanoDefine explicitly supported the governance challenges associated with the implementation of legislation concerning nanomaterials by:
- addressing the issues on availability of suitable measuring techniques, reference materials, validated methods, acceptable to all stakeholders (authorities, policy makers, commercial firms),
- developing an integrated and interdisciplinary approach and a close international co-operation and networking with academia, commercial firms and standardization bodies.
Thus, the NanoDefine Methods Manual provides guidance on practical implementation of the EC NM Definition throughout the nanomaterial characterization process, and on the characterization techniques employed as well as their application range and limits. It assists the user in choosing the most appropriate measurement method(s) to identify any substance or mixture for a specific purpose, according to the EC NM Definition of a nanomaterial. The NanoDefine project also explored how to assess a material against the criteria of the definition through proxy solutions, i.e. by applying measurement techniques that indirectly determine the x50. Those findings were developed through empirically based scientific work and are included in Part 1 of this Manual. As they go beyond the text of the EC NM Definition, they may be used as practical approach to indicate whether a material is a nanomaterial or not, but keeping in mind that they should not be taken as recommendation for the implementation of the EC NM Definition in a regulatory context.
The NanoDefine Methods Manual consists of the following three parts:
Part 1: The NanoDefiner Framework and Tools
Part 2: Evaluation of Methods
Part 3: Standard Operating Procedures (SOPs)
Part 1 covers the NanoDefiner framework, general information on measurement methods and performance criteria and tools developed by NanoDefine such as a materials categorisation system, a decision support flow scheme and an e-tool.
Part 2 discusses the outcome of the evaluation of the nanomaterials characterisation methods for measuring size.
Part 3 presents the 23 Standard Operating Procedures developed within the NanoDefine project.
The current document is part 2.
KW - Nanomaterial
KW - Nanoparticles
KW - NanoDefine
KW - Particle size distribution
KW - Nanomaterial classification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503708
SN - 978-92-76-11953-1
DO - https://doi.org/10.2760/071877
SN - 1831-9424
VL - JRC117501
SP - 1
EP - 133
PB - Publications Office of the European Union
CY - Luxembourg
AN - OPUS4-50370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Kun
A1 - Carrod, Andrew J.
A1 - Del Giorgio, Elena
A1 - Hughes, Joseph
A1 - Rurack, Knut
A1 - Bennet, Francesca
A1 - Hodoroaba, Vasile-Dan
A1 - Harrad, Stuart
A1 - Pikramenou, Zoe
T1 - Luminescence Lifetime-Based Sensing Platform Based on Cyclometalated Iridium(III) Complexes for the Detection of Perfluorooctanoic Acid in Aqueous Samples
N2 - Luminescence lifetimes are an attractive analytical method for detection due to its high sensitivity and stability. Iridium probes exhibit luminescence with long excited-state lifetimes, which are sensitive to the local environment. Perfluorooctanoic acid (PFOA) is listed as a chemical of high concern regarding its toxicity and is classified as a “forever chemical”. In addition to strict limits on the presence of PFOA in drinking water, environmental contamination from industrial effluent or chemical spills requires rapid, simple, accurate, and cost-effective analysis in order to aid containment. Herein, we report the fabrication and function of a novel and facile luminescence sensor for PFOA based on iridium modified on gold surfaces. These surfaces were modified with lipophilic iridium complexes bearing alkyl chains, namely, IrC6 and IrC12, and Zonyl-FSA surfactant. Upon addition of PFOA, the modified surfaces IrC6-FSA@Au and IrC12-FSA @Au show the largest change in the red luminescence signal with changes in the luminescence lifetime that allow monitoring of PFOA concentrations in aqueous solutions. The platform was tested for the measurement of PFOA in aqueous samples spiked with known concentrations of PFOA and demonstrated the capacity to determine PFOA at concentrations >100 μg/L (240 nM).
KW - Perfluorooctanoic Acid (PFOA)
KW - Cyclometalated iridium (III) complexes
KW - Luminescent lifetime
KW - Optically active surfaces
KW - ToF-SIMS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594535
UR - https://pubs.acs.org/doi/10.1021/acs.analchem.3c04289
DO - https://doi.org/10.1021/acs.analchem.3c04289
VL - 96
IS - 4
SP - 1565
EP - 1575
PB - American Chemical Society (ACS)
AN - OPUS4-59453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - How to perform reliable xps-measurements?
N2 - Reliable measurements are a great challenge in X-ray photoelectron spectroscopy. It will be shown, how to check the performance and calibration of the instrument, the charge compensation, quantification, fitting, and depth profiling.
T2 - Course for PhD students at SFB 1073
CY - Göttingen, Germany
DA - 23.02.2024
KW - X-ray photoelectron spectroscopy
KW - Reproducibility crisis
KW - Reliability
PY - 2024
AN - OPUS4-59590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritsch, Tobias
A1 - Sprengel, Maximilian
A1 - Evans, Alexander
A1 - Farahbod-Sternahl, L.
A1 - Saliwan Neumann, Romeo
A1 - Hofmann, M.
A1 - Bruno, Giovanni
T1 - On the determination of residual stresses in additively manufactured lattice structures
N2 - The determination of residual stresses becomes more complicated with increasing complexity of the structures investigated. Additive manufacturing techniques generally allow the production of ‘lattice structures’ without any additional manufacturing step. These lattice structures consist of thin struts and are thus susceptible to internal stress-induced distortion and even cracks. In most cases, internal stresses remain locked in the structures as residual stress.
The determination of the residual stress in lattice structures through nondestructive neutron diffraction is described in this work. It is shown how two difficulties can be overcome: (a) the correct alignment of the lattice structures within the neutron beam and (b) the correct determination of the residual stress field in a representative part of the structure. The magnitude and the direction of residual stress are discussed. The residual stress in the strut was found to be uniaxial and to follow the orientation of the strut, while the residual stress in the knots was more hydrostatic. Additionally, it is shown that strain measurements in at least seven independent directions are necessary for the estimation of the principal stress directions. The measurement directions should be chosen according to the sample geometry and an informed choice on the possible strain field. If the most prominent direction is not measured, the error in the calculated stress magnitude increases considerably.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Residual stress
KW - Principal stress components
KW - Neutron diffraction
KW - Lattice structures
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520663
DO - https://doi.org/10.1107/S1600576720015344
SN - 1600-5767
VL - 54
SP - 228
EP - 236
AN - OPUS4-52066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Fritsch, Tobias
A1 - Mishurova, Tatiana
A1 - Trofimov, Anton
A1 - Apel, D.
A1 - Ulbricht, Alexander
A1 - Kromm, Arne
A1 - Hesse, René
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - On the interplay of microstructure and residual stress in LPBF IN718
N2 - The relationship between residual stresses and microstructure associated with a laser powder bed fusion (LPBF) IN718 alloy has been investigated on specimens produced with three different scanning strategies (unidirectional Y-scan, 90° XY-scan, and 67° Rot-scan). Synchrotron X-ray energy-dispersive diffraction (EDXRD) combined with optical profilometry was used to study residual stress (RS) distribution and distortion upon removal of the specimens from the baseplate. The microstructural characterization of both the bulk and the nearsurface regions was conducted using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). On the top surfaces of the specimens, the highest RS values are observed in the Y-scan specimen and the lowest in the Rot-scan specimen, while the tendency is inversed on the side lateral surfaces. A considerable amount of RS remains in the specimens after their removal from the baseplate, especially in the Y- and Z-direction (short specimen Dimension and building direction (BD), respectively). The distortion measured on the top surface following baseplate thinning and subsequent removal is mainly attributed to the amount of RS released in the build direction. Importantly, it is observed that the additive manufacturing microstructures challenge the use of classic theoretical models for the calculation of diffraction elastic constants (DEC) required for diffraction-based RS analysis. It is found that when the Reuß model is used for the calculation of RS for different crystal planes, as opposed to the conventionally used Kröner model, the results exhibit lower scatter. This is discussed in context of experimental measurements of DEC available in the literature for conventional and additively manufactured Ni-base alloys.
KW - L-PBF IN718 material
KW - Effect of scanning strategies
KW - Near-surface X-ray diffraction
KW - Residual stress in AM
KW - Distortion upon baseplate removal
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519460
DO - https://doi.org/10.1007/s10853-020-05553-y
SN - 0022-2461
VL - 56
IS - 9
SP - 5845
EP - 5867
PB - Springer
AN - OPUS4-51946
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D.
A1 - Kozadayeva, M.
A1 - Manabaev, K.
A1 - Panin, A.
A1 - Sjöström, W.
A1 - Koptyug, A.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Meinel, Dietmar
A1 - Bruno, Giovanni
A1 - Cheneler, D.
A1 - Surmenev, R.
A1 - Surmeneva, M.
T1 - Different approaches for manufacturing Ti-6Al-4V alloy with triply periodic minimal surface sheet-based structures by electron beam melting
N2 - Targeting biomedical applications, Triply Periodic Minimal Surface (TPMS) gyroid sheet-based structures were successfully manufactured for the first time by Electron Beam Melting in two different production Themes, i.e., inputting a zero (Wafer Theme) and a 200 µm (Melt Theme) wall thickness. Initial assumption was that in both cases, EBM manufacturing should yield the structures with similar mechanical properties as in a Wafer-mode, as wall thickness is determined by the minimal beam spot size of ca 200 µm. Their surface morphology, geometry, and mechanical properties were investigated by means of electron microscopy (SEM), X-ray Computed Tomography (XCT), and uniaxial tests (both compression and tension). Application of different manufacturing Themes resulted in specimens with different wall thicknesses while quasi-elastic gradients for different Themes was found to be of 1.5 GPa, similar to the elastic modulus of human cortical bone tissue. The specific energy absorption at 50% strain was also similar for the two types of structures. Finite element simulations were also conducted to qualitatively analyze the deformation process and the stress distribution under mechanical load. Simulations demonstrated that in the elastic regime wall, regions oriented parallel to the load are primarily affected by deformation. We could conclude that gyroids manufactured in Wafer and Melt Themes are equally effective in mimicking mechanical properties of the bones.
KW - Electron beam melting
KW - Scaffold
KW - Lightweight structures
KW - Computed tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531595
DO - https://doi.org/10.3390/ma14174912
SN - 1996-1944
VL - 14
IS - 17
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-53159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Ulbricht, Alexander
A1 - Fritsch, Tobias
A1 - Mishurova, Tatiana
A1 - Kromm, Arne
A1 - Hofmann, M.
A1 - Wimpory, R. C.
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - Scanning Manufacturing Parameters Determining the Residual Stress State in LPBF IN718 Small Parts
N2 - The influence of scan strategy on the residual stress (RS) state of an as-built IN718 alloy produced by means of laser powder bed fusion (LPBF) is investigated. Two scan vector rotations (90°-alternation and 67°-rotation), each produced following two different scan vector lengths (long and short), are used to manufacture four rectangular prisms. Neutron diffraction (ND) and laboratory X-ray diffraction (XRD) techniques are used to map the bulk and surface RS state, respectively. The distortion induced upon removal from the baseplate is measured via profilometry. XRD measurements show that the two long scan vector strategies lead to higher RS when compared with the equivalent short scan vector strategies. Also, the 67°-rotation strategies generate lower RS than their 90°-alternation counterparts. Due to the lack of reliable stress-free d0 references, the ND results are analyzed using von Mises stress. In general, ND results show significant RS spatial non-uniformity. A comparison between ND and distortion results indicates that the RS component parallel to the building direction (Z-axis) has a predominant role in the Z-displacement. The use of a stress balance scheme allows to discuss the d0 variability along the length of the specimens, as well as examine the absolute RS state.
KW - As-built LPBF IN718 alloy
KW - Scan strategy influence
KW - Neutron diffraction
KW - Residual stress state
KW - Stress balance condition
KW - Distortion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526360
DO - https://doi.org/10.1002/adem.202100158
VL - 23
IS - 7
SP - 158
PB - Wiley
AN - OPUS4-52636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Paciornik, S.
A1 - Horvath, J.
A1 - Tushtev, K.
A1 - Rezwan, K.
A1 - Bruno, Giovanni
T1 - Evolution of Damage in All-Oxide Ceramic Matrix Composite After Cyclic Loading
N2 - While structural ceramics usually display a brittle mechanical behavior, their composites may show nonlinearities, mostly due to microcracking. Herein, the stiffness evolution of a sandwich-like laminate of an Al2O3 15%vol. ZrO2 matrix reinforced with Nextel 610 fibers is studied as a function of number of cycles N in tension. The stiffness of the composite degrades with increasing N, indicating microcracking. However, synchrotron X-ray refraction radiography shows that the internal specific surface of such cracks varies differently. A modeling strategy is developed for the calculation of the equivalent stiffness of mixtures (first the matrix and then the sandwich), based on the Voigt and Reuß schemes. The Bruno–Kachanov model is then used to estimate the initial microcrack density in the matrix (due to the thermal expansion mismatch) and the amount of microcracking increase upon cyclic loading. The stiffness in the composite degrades dramatically already after 20 000 cycles but then remains nearly constant. The combination of mechanical testing, quantitative imaging analysis, and modeling provides insights into the damage mechanisms acting: microcrack propagation is more active than microcrack initiation upon cyclic loading, but the second also occurs. This scenario is similar but not equal to previous results on porous and microcracked ceramics.
KW - Ceramic matrix composites
KW - Homogenization schemes
KW - Microcracking
KW - Nonlinear behavior
KW - Synchrotron X-ray refraction radiography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534541
DO - https://doi.org/10.1002/adem.202100763
SN - 1527-2648
SN - 1438-1656
VL - 24
IS - 6
SP - 2100763 -1
EP - 2100763 -13
PB - VCH GmbH
CY - Weinheim
AN - OPUS4-53454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauzon, C.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Dubiez-Le Goff, S.
A1 - Murugesan, S.
A1 - Bruno, Giovanni
A1 - Hryha, E.
T1 - Residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion as a function of process atmosphere and component design
N2 - The influence of the process gas, laser scan speed, and sample thickness on the build-up of residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion was studied. Pure argon and helium, as well as a mixture of those (30% helium), were employed to establish process atmospheres with a low residual Oxygen content of 100 ppm O2. The results highlight that the subsurface residual stresses measured by X-ray diffraction were significantly lower in the thin samples (220 MPa) than in the cuboid samples (645 MPa). This difference was attributed to the shorter laser vector length, resulting in heat accumulation and thus in-situ stress relief. The addition of helium to the process gas did not introduce additional subsurface residual stresses in the simple geometries, even for the increased scanning speed. Finally, larger deflection was found in the cantilever built under helium (after removal from the baseplate), than in those produced under argon and an argon-helium mixture. This result demonstrates that complex designs involving large scanned areas could be subjected to higher residual stress when manufactured under helium due to the gas’s high thermal conductivity, heat capacity, and thermal diffusivity.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Residual stress
KW - Process atmosphere
KW - Helium
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534209
DO - https://doi.org/10.1016/j.addma.2021.102340
VL - 47
SP - 2340
PB - Elsevier B.V.
AN - OPUS4-53420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritsch, Tobias
A1 - Farahbod-Sternahl, L.
A1 - Serrano-Munoz, Itziar
A1 - Léonard, F.
A1 - Haberland, C.
A1 - Bruno, Giovanni
T1 - 3D Computed Tomography Quantifies the Dependence of Bulk Porosity, Surface Roughness, and Re-Entrant Features on Build Angle in Additively Manufactured IN625 Lattice Struts
N2 - Layer-by-layer additive manufacturing (AM) by means of laser-powder bed Fusion (L-PBF) offers many prospects regarding the design of lattice structures used, for example, in gas turbines. However, defects such as bulk porosity, Surface roughness, and re-entrant features are exacerbated in nonvertical structures, such as tilted struts. The characterization and quantification of these kinds of
defects are essential for the correct estimation of fracture and fatigue properties.
Herein, cylindrical struts fabricated by L-PBF are investigated by means of X-ray computed tomography (XCT), with the aim of casting light on the dependence of the three kinds of defects (bulk porosity, surface roughness, and re-entrant features) on the build angle. Innovative analysis methods are proposed to correlate shape and position of pores, to determine the angular-resolved Surface roughness, and to quantify the amount of re-entrant surface features, q. A meshing of the XCT surface enables the correlation of q with the classical Surface roughness Pa. This analysis leads to the conclusion that there is a linear correlation between q and Pa. However, it is conjectured that there must be a threshold of surface roughness, below which no re-entrant features can be build.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Computed tomography
KW - Surface roughness analysis
KW - Re-entrant surface feature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534728
DO - https://doi.org/10.1002/adem.202100689
IS - 2100689
SP - 1
EP - 8
PB - Wiley-VCH Verlag
AN - OPUS4-53472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Evans, Alexander
A1 - Mishurova, Tatiana
A1 - Sprengel, Maximilian
A1 - Pirling, T.
A1 - Kromm, Arne
A1 - Bruno, Giovanni
T1 - The importance of subsurface residual stress in laser powder bed fusion IN718
N2 - The residual stress (RS) in laser powder bed fusion (LPBF) IN718 alloy samples produced using a 67°-rotation scan strategy is investigated via laboratory X-ray diffraction (XRD) and neutron diffraction (ND). The location dependence of the strain-free (d₀) lattice spacing in ND is evaluated using a grid array of coupons extracted from the far-edge of the investigated specimen. No compositional spatial variation is observed in the grid array. The calculated RS fields show considerable non-uniformity, significant stress gradients in the region from 0.6 to 2 mm below the surface, as well as subsurface maxima that cannot be accounted for via XRD. It is concluded that failure to determine such maxima would hamper a quantitative determination of RS fields by means of the stress balance method.
KW - Laser powder bed fusion
KW - Neutron and X-ray diffraction
KW - Residual stress analysis
KW - Strain-free lattice references
KW - Stress balance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532707
DO - https://doi.org/10.1002/adem.202100895
SN - 1615-7508
SN - 1527-2648
VL - 24
IS - 6
SP - 1
EP - 7
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pereira, Raíssa Monteiro
A1 - Lohbauer, Ulrich
A1 - Schulbert, Christian
A1 - Göken, Mathias
A1 - Wurmshuber, Michael
A1 - Campos, Tiago Bastos Moreira
A1 - Thim, Gilmar Patrocínio
A1 - Mieller, Björn
A1 - Belli, Renan
T1 - Instantiations of Multiscale Kinship in Pressing‐Defect Distributions in Yttria‐Stabilized Zirconias by Powder Partitioning
N2 - Modern dry pressing of ceramic powders using spray‐dried granulates cannot avoid the occurrence of defects related to persisting inter‐ and intra‐granulate interstitial voids. These constitute the parent defect size population limiting the application of polycrystalline ceramics in high‐stress conditions. The mitigation of such defects could widen the range of application in technical and biomedical engineering, reduce the safety range for design, and extend the lifetime of components. Herein, the Weibull size‐effect on strength in size‐partitioned Yttria‐stabilized zirconias (YSZ) feedstocks is used to explore the viability of changing the density distribution of granulate sizes as an effective strategy to obtain a denser particle packing that could reduce the size distribution of strength‐limiting pressing defects. In a direct assessment of critical defect size using multiscale strength testing with a dataset of ≈1300 values, the success of such an approach in increasing the strength reliability for small volume components is demonstrated, along with its ultimate failure in altering the defect size distribution in sintered YSZ ceramics across several length scales. Finally, it is shown that granule morphology (spherical or dimpled) fails to affect the defect density and size distribution in YSZ ceramics.
KW - Zirconia
KW - Strength
KW - Toughness
KW - Weibull distribution
KW - Defect population
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602697
DO - https://doi.org/10.1002/adem.202400139
SN - 1438-1656
SP - 1
EP - 17
PB - Wiley VHC-Verlag
AN - OPUS4-60269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silvestroni, L.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Ulbricht, Alexander
A1 - Wieder, Frank
A1 - Fritsch, Tobias
A1 - Sciti, D.
A1 - Bruno, Giovanni
T1 - Determination of short carbon fiber orientation in zirconium diboride ceramic matrix composites
N2 - In fiber-reinforced components, the fiber alignment and orientation have paramount influence on the thermomechanical properties of the resulting composite, for both short and continuous fiber. Here we present the case of an ultra-refractory matrix intended for extreme environment applications, ZrB2, reinforced with 20 vol% and 50 vol% short carbon fibers. In both cases, fibers tend to align perpendicular to the uniaxial pressure applied during shaping and sintering of a pellet, although the fiber tilt across the pellet thickness is difficult to determine. Moreover, for high volume fractions of reinforcement, the spatial distribution of the fibers is heterogeneous and tends to have domains of preferential orientations. We compare the information on the fiber distribution as collected by scanning electron microscopy images, X-ray computed tomography and synchrotron X-ray refraction radiography (SXRR). The three techniques prove to be complementary. Importantly, we demonstrate that SXRR yields the most statistically significant information due to the largest field of view, yet with a sensitivity down to the nanometer, and that can be successfully applied also to heavy matrix materials, such as zirconium boride.
KW - Ceramic matrix composites
KW - Synchrotron X-ray refraction radiography
KW - X-ray computed tomography
KW - Scanning electron microscopy
KW - High-temperature ceramics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597712
DO - https://doi.org/10.1016/j.jeurceramsoc.2024.02.048
SN - 0955-2219
VL - 44
IS - 8
SP - 4853
EP - 4862
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-59771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Fritsch, Tobias
A1 - Luzin, Vladimir
A1 - Ferrari, Bruno
A1 - Simón-Muzás, Juan
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - Impact of scan strategy on principal stresses in laser powder bed fusion
N2 - Additive manufacturing techniques, such as laser powder bed fusion (PBF-LB), are well known for their exceptional freedom in part design. However, these techniques are also characterized by the development of large thermal gradients during production and thus residual stress (RS) formation in produced parts. In this context, neutron diffraction enables the non-destructive characterization of the bulk RS distribution. By control of the thermal gradients in the powder-bed plane by scan strategy variation we study the impact of in-process scan strategy variations on the microstructure and the three-dimensional distribution of RS. Microstructural analysis by means of electron backscatter diffraction reveals sharp microstructure transitions at the interfaces ranging from 100-200 µm. The components of the RS tensor are determined by means of neutron diffraction and the principal stress directions and magnitudes are determined by eigenvalue decomposition. We find that the distribution of RS in the powder-bed plane corresponds to the underlying scan strategy. When the alternating scan vectors align with the x- and y sample coordinate axes, the principal stress directions co-align. In the present geometry, nearly transverse isotropic stress states develop when the scan vectors are either aligned 45° between x and y or continuously rotated by 67° between each layer.
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Electron Backscatter Diffraction
KW - Neutron Diffraction
KW - Residual Stress
KW - Principal Stress
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607910
DO - https://doi.org/10.1016/j.matdes.2024.113171
SN - 0264-1275
VL - 244
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-60791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mieller, Björn
A1 - Hassine, Sahar Ben
A1 - Töpfer, Jörg
A1 - Priese, Christoph
A1 - Bochmann, Arne
A1 - Capraro, Beate
A1 - Stark, Sebastian
A1 - Partsch, Uwe
A1 - Fresemann, Carina
T1 - Ontology‐based Data Acquisition, Refinement, and Utilization in the Development of a Multilayer Ferrite Inductor
N2 - A key aspect in the development of multilayer inductors is the magnetic permeability of the ferrite layers. Here, the effects of different processing steps on the permeability of a NiCuZn ferrite is investigated. Dry pressed, tape cast, and co‐fired multilayer samples are analyzed. An automated data pipeline is applied to structure the acquired experimental data according to a domain ontology based on PMDco (Platform MaterialDigital core ontology). Example queries to the ontology show how the determined process‐property correlations are accessible to non‐experts and thus how suitable data for component design can be identified. It is demonstrated how the inductance of co‐fired multilayer inductors is reliably predicted by simulations if the appropriate input data corresponding to the manufacturing process is used.This article is protected by copyright. All rights reserved.
KW - Ontology
KW - Ceramic multilayer
KW - Data pipeline
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605483
DO - https://doi.org/10.1002/adem.202401042
SN - 1527-2648
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-60548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mieller, Björn
A1 - Valavi, Masood
A1 - Caldeira Rêgo, Celso Ricardo
T1 - An Automatized Simulation Workflow for Powder Pressing Simulations Using SimStack
N2 - Automated computational workflows are a powerful concept that can improve the usability and reproducibility of simulation and data processing approaches. Although used very successfully in bioinformatics, workflow environments in materials science are currently commonly applied in the field of atomistic simulations. This work showcases the integration of a discrete element method (DEM) simulation of powder pressing in the convenient SimStack workflow environment. For this purpose, a Workflow active Node (WaNo) was developed to generate input scripts for the DEM solver using LIGGGHTS Open Source Discrete Element Method Particle Simulation code. Combining different WaNos in the SimStack framework makes it possible to build workflows and loop over different simulation or evaluation conditions. The functionality of the workflows is explained, and the added user value is discussed. The procedure presented here is an example and template for many other simulation methods and issues in materials science and engineering.
KW - Simulation workflow
KW - Discrete element method
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604791
DO - https://doi.org/10.1002/adem.202400872
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-60479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, Michela
A1 - Tsamos, Athanasios
A1 - Faglioni, Francesco
A1 - Fioresi, Rita
A1 - Zanchetta, Ferdinando
A1 - Bruno, Giovanni
T1 - Geometric deep learning for enhanced quantitative analysis of microstructures in X-ray computed tomography data
N2 - Quantitative microstructural analysis of XCT 3D images is key for quality assurance of materials and components. In this paper we implement a Graph Convolutional Neural Network (GCNN) architecture to segment a complex Al-Si Metal Matrix composite XCT volume (3D image). We train the model on a synthetic dataset and we assess its performance on both synthetic and experimental, manually-labeled, datasets. Our simple GCNN shows a comparable performance, measured via the Dice score, to more standard machine learning methods, but uses a greatly reduced number of parameters (less than 1/10 of parameters), features low training time, and needs little hardware resources. Our GCNN thus achieves a cost-effective reliable segmentation.
KW - Geometric deep learning
KW - Segmentation
KW - Microstructure
KW - X-ray computed tomography
KW - Al–Si metal matrix composites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602517
DO - https://doi.org/10.1007/s42452-024-05985-0
SN - 3004-9261
VL - 6
IS - 6
SP - 1
EP - 9
AN - OPUS4-60251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Reaction sintering and sintering additives for cost-effective production of thermoelectric oxides
N2 - Thermoelectric oxides attract much interest recently. Although their thermoelectric properties are inferior to non-oxides, they exhibit distinct advantages. Thermoelectric oxides are stable in air at higher temperatures, their raw materials are less toxic, and more abundant. To enhance attractivity of these materials for industrial applications, production costs need to be reduced.
Conventionally, the legs of thermoelectric generators are sintered from green bodies of previously synthesized powder. Reaction-sintering is a fabrication method without a powder synthesis step, as the final phase is formed during the sintering from a raw material mixture. Moreover, the reduction of chemical potential during reaction-sintering is effective as an additional driving force for sintering. We show that reaction-sintering increases the densification of CaMnO3 (n-type, Sm doped). Consequently, the electrical conductivities improved by about 100 % leading to superior power factors (PF = 230 µW/mK² for CaMnO3).
Another approach to reduce the production costs is to lower the sintering temperature by adding sinter additives. The addition of 4 wt% CuO to CaMnO3 lowers the sinter temperature from 1250 °C to 1050 °C. The achieved power factor PF = 264 µW/mK is more than two times higher as reported in literature for the same dopant.
T2 - Virtual Conference on Thermoelectrics (VCT)
CY - Online meeting
DA - 21.07.2020
KW - Thermoelectrics
KW - Reaction sintering
KW - Sintering additives
KW - Calcium manganate
KW - Calcium cobaltite
PY - 2020
AN - OPUS4-51070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Procedures to Quantitatively Characterize Morphological Features of Triply Periodic Minimal Surface Structures
N2 - Additively manufactured (AM) metallic sheet-based Triply Periodic Minimal Surface Structures (TPMSS) meet several requirements in both bio-medical and engineering fields: Tunable mechanical properties, low sensitivity to manufacturing defects, mechanical stability, and high energy absorption. However, they also present some challenges related to quality control. In fact, the optimization of both the AM process and the properties of TPMSS is impossible without considering structural characteristics as manufacturing accuracy, internal defects, and as well as surface topography and roughness. In this study, the quantitative non-destructive analysis of TPMSS manufactured from Ti-6Al-4V alloy by electron beam melting was performed by means of laboratory X-ray computed tomography (XCT).
T2 - International conference on tomography of material and structures 2022
CY - Grenoble, France
DA - 27.06.2022
KW - Additive manufacturing
KW - Scaffold
KW - Lightweight structures
KW - Computed tomography
PY - 2022
AN - OPUS4-55229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reveron, H.
A1 - Serrano-Munoz, Itziar
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Chevalier, J.
A1 - Bruno, Giovanni
T1 - Transformation-induced plasticity in zirconia during tensile loading: A combined microscopy and synchrotron X-ray refraction study
N2 - The stress-induced tetragonal to monoclinic (t-m) zirconia phase transformation can provide a certain degree of plasticity to Ceria-stabilized (Ce-TZP) zirconia-based composites. Characterizing and monitoring this phase transition on a millimeter-size range, within the bulk and in-situ remains a challenge. In this work, the mechanical behavior of Ce-TZP based composite was studied in tension, combining microscopy and synchrotron Xray refraction techniques. In contrast with microscopy methods, which only provide surface information, X-ray refraction radiography (SXRR) allowed the visualization of all the transformation bands, over the entire length and thickness of tested specimens, opening up new avenues for in-situ stress-induced t-m transformation studies.
KW - Zirconia
KW - Ceria
KW - Composite
KW - Phase transformation
KW - Plasticity
KW - Synchrotron X-ray refraction
PY - 2024
DO - https://doi.org/10.1016/j.matlet.2024.136445
SN - 0167-577X
SN - 1873-4979
VL - 366
SP - 1
EP - 4
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-59977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
A1 - Mieller, Björn
A1 - Rabe, Torsten
A1 - Markötter, Henning
ED - Petzow, G.
ED - Mücklich, F.
T1 - Machine learning assisted characterization of a Low Temperature Cofired Ceramic (LTCC) module measured by synchrotron computed tomography
N2 - The 5G technology promises real time data transmission for industrial processes, autonomous driving, virtual and augmented reality, E-health applications and many more. The Low Temperature Co-fired Ceramics (LTCC) technology is well suited for the manufacturing of microelectronic components for such applications. Still, improvement of the technology such as further miniaturization is required. This study focuses on the characterization of inner metallization of LTCC multilayer modules, especially on the vertical interconnect access (VIA). Critical considerations for this characterization are delamination, pore clustering in and at the edge of the VIA, deformation, and stacking offset. A LTCC multilayer consisting of a glassy crystalline matrix with silver based VIAs was investigated by synchrotron x-ray tomography (CT). The aim of this study is to propose a multitude of structural characteristic values to maximize the information gained from the available dataset. Data analysis has been done with the open source software ImageJ as well as several additional plugins. The high-resolution CT data was evaluated through 2D slices for accessibility reasons. The segmentation of all 2000 slices to assess the different regions e.g. pores, silver and glass ceramic was done by a supervised machine learning algorithm. A quantitative evaluation of shape, deformation, and porosity of the VIA with respect to its dimensions is presented and the suitability of the characterization approach is assessed.
T2 - 54. Metallographie Taagung
CY - Online meeting
DA - 16.09.2020
KW - Machine Learning
KW - LTCC
KW - Synchrotron Tomography
PY - 2020
SN - 978-3-88355-422-8
VL - 54
SP - 136
EP - 141
PB - Deutsche Gesellschaft für Materialkunde e.V
CY - Sankt Augustin
AN - OPUS4-51298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging
N2 - Modern air-liners and rotor blades of wind turbines are basically made of fiber reinforced plastics (FRP). Their failure heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in-situ non-destructive testing techniques. Here, we report on in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics (CFRP) due to inter fiber failure. An in-house designed compact-tensile testing machine with a load range up to 15 kN was integrated into the beam path. Since conventional radiographs do not reveal sufficient contrast to distinct cracks due to inter fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging technique (DEI) is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. In the laboratory, scanning X-ray refraction topography of CFRP has been applied long before but it comes along with several disadvantages: the long total measuring time hampers real time (in-situ) measurements and the required small beam size hinders end-to-end imaging. The introduced technique overcomes both drawbacks. Imaging and tensile test rig are run unsynchronized at the greatest possible frame rate (0.7 s-1 at 28.8 µm pixel size) and smallest possible strain rate (5.5∙10-4 s-1). For 0°/90° non-crimped fabrics (ncf) the first inter fiber cracks occurred at 380 MPa (strain 0.7 %). Prior to failure at about 760 MPa (strain 2.0 %) we observe the evolution of a nearly equidistant 1 mm grid of cracks running across the entire sample in the fully damaged state before total failure.
T2 - 41st Risø International Symposium on Materials Science - Materials and Design for Next Generation Wind Turbine Blades
CY - Online meeting
DA - 07.09.2020
KW - X-ray refraction
KW - Diffraction Enhanced Imaging
KW - Carbon Fiber Reinforced Plastics
KW - In situ tensile test
KW - Crack evolution
PY - 2020
AN - OPUS4-51223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging
N2 - Modern air-liners and wind turbine rotor blades are made up primarily of fiber reinforced plastics. Failure of these materials heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in-situ non-destructive testing techniques. Here, we report in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics due to inter-fiber failure. An inhouse designed compact tensile testing machine with a load range up to 15 kN was integrated into the beamline. Since conventional radiographs do not reveal sufficient contrast to distinguish cracks due to inter-fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging (DEI) technique is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. This technique allows fast measurements over large fields-of-view and is ideal for in-situ investigations.
T2 - 12th BESSY@HZB User Meeting 2020
CY - Online meeting
DA - 10.12.2020
KW - Carbon Fiber Reinforced Plastics
KW - Crack evolution
KW - Diffraction Enhanced Imaging
KW - In situ tensile test
KW - X-ray refraction
PY - 2020
AN - OPUS4-51802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Improved thermoelectric properties of CaMnO3 and Ca3Co4O9 by increasing the driving force for sintering
N2 - Thermoelectric materials can convert waste heat directly into electrical power by utilizing the Seebeck effect. Calcium cobaltite (Ca3Co4O9, p-type) and calcium manganate (CaMnO3, n-type) are two of the most promising oxide thermoelectric materials. The performance of these materials is evaluated by the power factor PF = S²∙σ and the figure of merit ZT = (PF ∙ T) / κ, demanding high Seebeck coefficient S, high electrical conductivity σ and low thermal conductivity κ. The latter two are increasing with increasing relative sinter density. According to theory, the relative density of ceramics can be improved by increasing the driving force for sintering. This study investigates different approaches to increase the driving force for sintering of Ca3Co4O9 and CaMnO3 to improve densities and thermoelectric properties.
The following approaches were applied: minimizing the energy input during powder synthesis by calcination, fine milling of the powder, using reaction-sintering without a powder synthesis step, and adding a transient liquid phase by sinter additives.
All different approaches led to an increased densification and thus higher electrical conductivity and higher PF. Thermal conductivity increased as well but not to the same extent. E.g. reaction-sintering increased the densification of Ca3Co4O9 (p-type) and CaMnO3 (n-type). Consequently, the electrical conductivities improved by about 100 % for both oxides leading to superior power factors (PF = 230 µW/mK² for CaMnO3). Although the thermal conductivity increased as well by 8 %, the figures of merit (ZT) were significantly higher compared to conventionally sintered bars. The addition of 4 wt% CuO as a sinter additive to CaMnO3 lowers the sinter temperature from above 1250 °C to below 1100 °C and increases the relative density. Due to the increased density, both electrical conductivity and PF increased by more than 200 % even though the sintering temperature was 150 K lower.
T2 - Electroceramics XVII
CY - Online meeting
DA - 24.08.2020
KW - Thermoelectrics
KW - Reaction sintering
KW - Sintering additives
PY - 2020
AN - OPUS4-51163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Practical breakdown voltage calculations using dielectric breakdown strength reference values
N2 - Dielectric breakdown is a catastrophic failure of ceramic substrates and insulators. The use of dielectric breakdown strength (DBS) reference values for the dimensioning of such components is not straightforward, as the DBS depends on sample thickness and electrode area. This fact also hampers a valid comparison of data taken from different literature sources. Based on the empirically confirmed proportionality of DBS to the reciprocal square root of sample thickness and an approach to account for the influence of electrode area on the failure probability, a practical equation is derived to calculate the breakdown voltage for arbitrary sample thickness and electrode area from one set of DBS reference data. To validate the equation, the AC DBS of commercial alumina substrates with thicknesses ranging from 0.3 mm to 1.0 mm was performed using different printed electrodes with varying areas. The breakdown voltages comprise a range from 18 kV for thick samples to 8.5 kV for thin samples, resulting in DBS values from 17 kV/mm for 1.0 mm thick samples to 29 kV/mm for 0.3 mm thin samples, all made from the same material. The influence of electrode area is comparatively smaller. The results calculated with the proposed equation are in reasonable accordance with the measured data. Thus, the equation can be applied for a proper comparison of literature DBS data measured in different setups and for a reasonable estimation of breakdown voltages in DBS tests and applications based on reference data.
T2 - Electroceramics Conference XVII
CY - Online meeting
DA - 24.08.2020
KW - Ceramics
KW - Dielectric breakdown
KW - Weibull distribution
PY - 2020
AN - OPUS4-51151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Machine learning assisted characterization of a Low Temperature Co-fired Ceramic (LTCC) module measured by synchrotron computed tomography.
N2 - The 5G technology promises real time data transmission for industrial processes, autonomous driving, virtual and augmented reality, E-health applications and many more. The Low Temperature Co-fired Ceramics (LTCC) technology is well suited for the manufacturing of microelectronic components for such applications. Still, improvement of the technology such as further miniaturization is required. This study focuses on the characterization of inner metallization of LTCC multilayer modules, especially on the vertical interconnect access (VIA). Critical considerations for this characterization are delamination, pore clustering in and at the edge of the VIA, deformation, and stacking offset. A LTCC multilayer consisting of a glassy crystalline matrix with silver based VIAs was investigated by synchrotron x-ray tomography (CT). The aim of this study is to propose a multitude of structural characteristic values to maximize the information gained from the available dataset. Data analysis has been done with the open source software ImageJ as well as several additional plugins. The high-resolution CT data was evaluated through 2D slices for accessibility reasons. The segmentation of all 2000 slices to assess the different regions e.g. pores, silver and glass ceramic was done by a supervised machine learning algorithm. A quantitative evaluation of shape, deformation, and porosity of the VIA with respect to its dimensions is presented and the suitability of the characterization approach is assessed.
T2 - 54. Metallographie Tagung
CY - Online meeting
DA - 16.09.2020
KW - Machine Learning
KW - LTCC
KW - Synchrotron Tomography
PY - 2020
AN - OPUS4-51299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Léonard, Fabien
A1 - Zhang, Zhen
A1 - Malow, Marcus
A1 - Bruno, Giovanni
T1 - 3D characterisation of ammonium nitrate powders by X-ray computed tomography
N2 - The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually called ANFO, is extensively used in the mining industry as a bulk industrial explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the porosity of the AN prills. Standardised tests routinely used to assess oil retention face several important limitations; the first being the difficulty to cover the wide range of porosity contents and morphologies from different types of ammonium nitrate prills; the second being the inability to evaluate the closed porosity, which is an important factor regarding the sensitivity of the explosive to detonation. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. XCT can therefore be employed to non-destructively and accurately evaluate and characterise porosity in ammonium nitrate prills.
T2 - 23rd Seminar on New Trends in Research of Energetic Materials
CY - Meeting was canceled
DA - 01.04.2020
KW - Ammonium nitrate
KW - Prill
KW - Non-destructive characterisation
KW - Porosity
KW - Specific surface area
PY - 2020
SP - 163
EP - 171
AN - OPUS4-51272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Diffraction based residual stress analysis for laser powder bed fusion alloys
N2 - Laser Powder Bed Fusion (PBF-LB/M) is a layer wise metal additive manufacturing (AM) technology, which enables significant advancements of component design, leading to potential efficiency and performance improvements. However, the thermal cycles inherent to the process comprising large localized thermal gradients and repeated melting and solidification cycles leads to the generation of high magnitude residual stresses. These residual stresses can be detrimental both during manufacturing of components and in subsequent application. Therefore, a deep understanding of the influence of process parameters on the residual stresses are crucial for efficient manufacturing and safe application. The experimental characterization of these residual stresses is therefore crucial and can provide a reliable baseline for simulations of both the process and applications.
Diffraction-based methods for residual stress analysis using penetrating neutrons and high energy X-rays enable non-destructive spatially resolved characterization of both surface and bulk residual stresses. However, the unique microstructural features inherent to the process can challenge some of our assumptions when using these methods. These challenges include the determination of a stress-free reference, the use of correct elastic constants (both SCEC and DEC) and the influence of surface roughness, texture, and porosity on residual stresses.
This presentation will detail recent insights and recommendations for the characterization of residual stresses in a range of PBF-LB/M metallic alloys (Fe, Ni, Al and Ti)
T2 - 11th edition of the European Conference on Residual Stress (ECRS11)
CY - Prague, Czech Republic
DA - 03.06.2024
KW - Residual stress
KW - Additive manufacturing
KW - Laser Powder Bed Fusion
KW - Diffraction
PY - 2024
AN - OPUS4-60443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rieder, Philipp
A1 - Petrich, Lukas
A1 - Serrano-Munoz, Itziar
A1 - Fernández, Ricardo
A1 - Bruno, Giovanni
A1 - Schmidt, Volker
T1 - Statistical Comparison of Substructures in Pure Aluminum Before and After Creep Deformation, Based on EBSD Image Data
N2 - Electron backscatter diffraction (EBSD) images of extruded pure aluminum were statistically analyzed to investigate creep-induced subgrain structures after applying two different levels of creep stress, corresponding to the power law (PL) and power-law breakdown (PLB) regimes. Kernel average misorientation analysis of EBSD measurements revealed 2D morphologies, which were subdivided by a multi-step segmentation procedure into subgranular arrangements. Various descriptors were employed to characterize the “subgrains” quantitatively, including their size, shape, spatial arrangement, and crystallographic orientation. In particular, the analysis of the orientations of subgrains was conducted by neglecting rotations around the loading axis. This approach facilitated the individual investigation of the {001} and {111} subgrain families with respect to the loading axis for two investigated stress levels plus a reference specimen. For the PL regime, the statistical analysis of subgrain descriptors computed from segmented image data revealed a similar degree of strain accumulation for {111} and {001} subgrains. In contrast, for the PLB regime, the analyzed descriptors indicate that {111} subgrains tend to accumulate significantly more strain than {001} ones. These observations suggest that the mechanisms leading to PLB may be associated with strain localization dependent on intergranular stress, hindering the recovery process within {111} grains.
KW - Crystallographic descriptor
KW - Dislocation-climb-controlled creep
KW - Electron backscatter diffraction (EBSD)
KW - Geometric descriptor
KW - Ernel average misorientation (KAM)
KW - pure aluminum
KW - Qquantification and segmentation
KW - Statistical image analysis
KW - subgrain
PY - 2023
DO - https://doi.org/10.1093/micmic/ozad121
SN - 1431-9276
SP - 1
EP - 12
PB - Oxford University Press
AN - OPUS4-58730
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schob, D.
A1 - Sagradov, I.
A1 - Roszak, R.
A1 - Sparr, H.
A1 - Franke, R.
A1 - Ziegenhorn, M.
A1 - Kupsch, Andreas
A1 - Léonard, Fabien
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Experimental determination and numerical simulation of material and damage behaviour of 3D printed polyamide 12 under cyclic loading
N2 - The material and damage behaviour of additively manufactured polyamide 12 under cyclic loading was characterized by cyclic tests and microstructure analysis by using microscopy, X-ray refraction, and computed tomography. The results were used to determine parameters for the viscoplastic material model by Chaboche and a damage model by Gurson-Tvergaard-Needleman. The temperature was monitored during the experiments and the self-heating effect was observed. By including this effect, a higher accuracy could be achieved with the results of mechanical experiments.
KW - 3D printing Polyamide 12
KW - Chaboche model
KW - GTN model
KW - Material and damage behaviour
KW - X-ray refraction
KW - Computed tomography
PY - 2020
DO - https://doi.org/10.1016/j.engfracmech.2019.106841
SN - 0013-7944
VL - 229
SP - 106841-1
EP - 106841-13
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-50557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
A1 - Evsevleev, Sergei
A1 - Sevostianov, I.
T1 - Determination of macroscopic stress from diffraction experiments: A critical discussion
N2 - The paper is motivated by some inconsistencies and contradictions present in the literature on the calculation of the so-called diffraction elastic constants. In an attempt at unifying the views that the two communities of Materials Science and Mechanics of Materials have on the subject, we revisit and define the terminology used in the field. We also clarify the limitations of the commonly used approaches and Show that a unified methodology is also applicable to textured materials with a nearly arbitrary grain shape. We finally compare the predictions based on this methodology with experimental data obtained by in situ synchrotron radiation diffraction on additively manufactured Ti-6Al4V alloy. We show that (a) the transverse isotropy of the material yields good agreement between the best-fit isotropy approximation (equivalent to the classic Kröner’s model) and the experimental data and (b) the use of a general framework allows the calculation of all components of the tensor of diffraction elastic constants, which are not easily measurable by diffraction methods. This allows us to extend the
current state-of-the-art with a predictive tool.
KW - Additive manufacturing
KW - X-ray diffraction
KW - Elastic constants
KW - Stress concentration tensor
PY - 2020
DO - https://doi.org/10.1063/5.0009101
VL - 128
IS - 2
SP - 025103
PB - AIP Publishing
AN - OPUS4-50993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lorenzoni, R.
A1 - Curosu, I.
A1 - Léonard, Fabien
A1 - Paciornik, S.
A1 - Mechtcherine, V.
A1 - Silva, F. A.
A1 - Bruno, Giovanni
T1 - Combined mechanical and 3D-microstructural analysis of strain-hardening cement-based composites (SHCC) by in-situ X-ray microtomography
N2 - The paper presents the results of a series of combined mechanical and in-situ morphological investigations on highstrength strain-hardening cement-based Composites (SHCC). Tension and compression experiments were performed in a CT scanner employing a dedicated mechanical testing rig. The in-situ microtomographic scans enabled correlating the measured specimen response with relevant microstructural features and fracture processes. The microstructural segmentation of SHCC was performed in the framework of Deep Learning and it targeted an accurate segmentation of pores, fibers and aggregates. Besides their accurate volumetric representation, these phases were quantified in terms of content, size and orientation. The fracture processes were monitored at different loading stages and Digital Volume Correlation (DVC) was employed to spatially map the strains and cracks in the specimens loaded in compression. The DVC analysis highlighted the effect of loading conditions, specimen geometry and material heterogeneity at the mesolevel on the strain distribution and fracture localization.
KW - Digital Volume Correlation
KW - High Strength Concrete
KW - In-situ Computed Tomography
KW - composites
PY - 2020
DO - https://doi.org/10.1016/j.cemconres.2020.106139
VL - 136
SP - 106139
PB - Elsevier Ltd.
AN - OPUS4-51054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernández, R.
A1 - Bokuchava, G.
A1 - Toda-Caraballo, I.
A1 - Bruno, Giovanni
A1 - Turchenko, V.
A1 - Gorshkova, Y.
A1 - González-Doncel, G.
T1 - Analysis of the Combined Strengthening Effect of Solute Atoms and Precipitates on Creep of Aluminum Alloys
N2 - The creep strengthening mechanisms in (age-hardenable) aluminum alloys are analyzed on the basis of a new microstructural study of powder samples, an analysis of a comprehensive revision of creep data from the literature, and a new modeling approach. A strategy based on the strength difference (SD) method to separate the contributions of solid solution atoms and precipitates to creep strengthening is proposed. The new methodology considers the combination of the two contributions avoiding the need of a threshold stress term in the creep equation. The contribution of both precipitates and solid solution is taken into account by means of the analysis of the lattice parameter variation with aging time. For this study, powders of two commercial AA2xxx alloys have been analyzed using diffraction methods. The experimental results are modeled using Lubarda’s approach combined with the SD method.
KW - Composites
KW - Aluminum alloys
KW - Creep models
KW - Neutron Diffraction
KW - Stress exponent
PY - 2020
DO - https://doi.org/10.1002/adem.201901355
VL - 22
IS - 4
SP - 1901355
PB - WILEY-VCH Verlag
AN - OPUS4-51055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
A1 - Fernández, R.
A1 - Garcés, G.
A1 - Nieto-Luis, H.
A1 - Gonzáles-Doncel, G.
T1 - Fractional brownian motion of dislocations during creep deformation of metals
N2 - The present work offers an explanation on how the long-range interaction of dislocations influences their movement, and therefore the strain, during creep of metals. It is proposed that collective motion of dislocations can be described as a fractional Brownian motion. This explains the noisy appearance of the creep strain signal as a function of time. Such signal is split into a deterministic and a stochastic part. These terms can be related to two kinds of dislocation motions: individual and collective, respectively. The description is consistent with the fractal nature of strain-induced dislocation structures predicated in previous works. Moreover, it encompasses the evolution of the strain rate during all stages of creep, including the tertiary one. Creep data from Al99.8% and Al- 3.85%Mg tested at different temperatures and stresses are used to validate the proposed ideas: it is found that different creep stages present different diffusion characters, and therefore different dislocation motion character.
KW - Metals
KW - Fractional brownian motion
KW - Creep deformation
PY - 2020
DO - https://doi.org/10.1016/j.msea.2020.140013
VL - 796
SP - 140013
PB - Elsevier B.V.
CY - Paris
AN - OPUS4-51450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Micromechanics of internal stresses in multiphase materials Part I- Residual Stress analysis by Diffraction
N2 - In this Seminar cycle I will present first diffraction methods to determine residual stress and investigate micromechanical properties of complex materials, and then particularize the treatment with applications to porous microcracked ceramics for diesel particulate filter applications.
I will show that neutron diffraction is particularly suited for bulk studies, where 3D stresses are needed. The advantages to use Time-of-Flight or steady state sources will be discussed, together with the problematic of the determination of absolute RS values.
Finally, the behavior of DPF materials under applied load or at high temperatures will be discussed under the combination of macroscopic and microscopic tests.
T2 - ATHOR webinar "Micromechanics of internal stresses in multiphase materials"
CY - Online meeting
DA - 12.01.2021
KW - Porosity
KW - Neutron Diffraction
KW - Residual Stress
KW - Non-linear stress-strain
KW - Anisotropy
KW - Microcracking
KW - Imaging
PY - 2021
AN - OPUS4-52125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - Using Neutron Diffraction to Monitor Stress Relaxation in Additively Manufactured 316L
N2 - The relaxation of residual stress in laser powder bed fused stainless steel 316L parts was monitored using monochromatic and time-of-flight neutron diffraction.
T2 - ISIS student meeting
CY - Online meeting
DA - 26.10.2020
KW - Stainless Steel
KW - Residual Stress
KW - Additive Manufacturing
PY - 2020
AN - OPUS4-51469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evsevleev, Sergei
T1 - Micromechanical response of multi-phase Al-alloy matrix composites under uniaxial compression
N2 - Aluminum alloys are extensively used in the automotive industry. Particularly, squeeze casting production of Al-Si alloys is employed in the conception of metal matrix composites (MMC) for combustion engines. Such materials are of a high interest since they allow combining improved mechanical properties and reduced weight and hence improve efficiency. Being a multiphase material, most MMCs show complex micromechanical behavior under different load conditions. In this work we investigated the micromechanical behavior of two MMCs, both consisting of a near-eutectic cast AlSi12CuMgNi alloy, one reinforced with 15%vol. Al2O3 short fibers and the other with 7%vol. Al2O3 short fibers + 15%vol. SiC particles. Both MMCs have complex 3D microstructure consisting of four and five phases: Al-alloy matrix, eutectic Si, intermetallics, Al2O3 fibers and SiC particles.
The in-situ neutron diffraction compression experiments were carried out on the Stress-Spec beamline and disclosed the evolution of internal phase-specific stresses in both composites. In combination with the damage mechanism revealed by synchrotron X-ray computed tomography (SXCT) on plastically pre-strained samples, this allowed understanding the role of every composite’s phase in the stress partitioning mechanism. Finally, based on the Maxwell scheme, a micromechanical model was utilized. The model perfectly rationalizes the experimental data and predicts the evolution of principal stresses in each phase.
T2 - MLZ User Meeting 2020
CY - Online meeting
DA - 09.12.2020
KW - Metal matrix composite
KW - Neutron diffraction
KW - Damage mechanism
KW - Load transfer
KW - Computed tomography
PY - 2020
AN - OPUS4-52032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Influence of the scanning strategy on the residual stress state in IN718 additive manufactured parts
N2 - Laser Powder Bed Fusion (L-PBF) is an additive manufacturing technique enabling the design of complex geometries that are unrivalled by conventional production technologies. Nevertheless, L-PBF process is known to induce a high amount of residual stresses (RS) due to the high temperature gradients present during powder melting by laser. High tensile residual stresses are to be found the edges whereas the bulk material shows balancing compressive RS. Literature shows that the RS is highly sensitive to the process parameters. In particular, this study presents the characterization of the RS state in two L-PBF parts produced with a rastering scan vector that undergoes 90° or 67° rotation between subsequent layers.
T2 - MLZ User Meeting 2020
CY - Online meeting
DA - 08.12.2020
KW - Laser Powder Bed Fusion
KW - IN718
KW - EBSD analysis
KW - Residual stress state
PY - 2020
AN - OPUS4-51821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Mishurova, Tatiana
A1 - Fritsch, Tobias
A1 - Serrano-Munoz, Itziar
A1 - Evans, Alexander
A1 - Sprengel, Maximilian
A1 - Klaus, M.
A1 - Genzel, C.
A1 - Schneider, J.
A1 - Bruno, Giovanni
T1 - On the influence of heat treatment on microstructure and mechanical behavior of laser powder bed fused Inconel 718
N2 - A range of heat treatments have been developed for wrought Inconel 718 to obtain desired properties. For additively manufactured Inconel 718, the recently developed standard ASTM F3301 provides guidance for heat treatment of powder bed fusion specimens. Although this standard is based on standards developed for wrought Inconel 718, it does not include direct aging. Since direct aging reduces the number of processing steps, it can result in a post processing cost reduction if the desired properties are obtained. In this study, we characterized the microstructure and tensile behavior of Inconel 718 specimens produced by a laser powder bed fusion process. The specimens were heat treated according to two different routines after stress relieving: a full heat Treatment versus a one-step direct aging process. Differences in the resulting texture and grain morphology were observed.
The ex-situ stress-strain behavior was broadly similar. However, a slight increase in yield strength was observed for the direct aged specimen. In order to understand this behavior, investigations with in-situ synchrotron Energy dispersive X-ray diffraction tensile testing revealed differences in the load partitioning among different Crystal directions. Importantly, the elastic anisotropy expressed by the magnitude of the diffraction elastic constants showed a dependency on the microstructures.
KW - Electron microscopy
KW - X-ray analysis
KW - Inconel 718
KW - Additive Manufacturing
KW - Mechanical behavior
KW - Diffraction elastic constants
PY - 2021
DO - https://doi.org/10.1016/j.msea.2020.140555
VL - 805
SP - 40555
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-52142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berndard, D.
A1 - Léonard, Fabien
A1 - Plougonven, E.
A1 - Bruno, Giovanni
T1 - On the use of autocorrelation functions, permeability tensors, and computed tomography to characterise the anisotropy of diesel particulate filter materials
N2 - We show how the combination of the spatial autocorrelation function and permeability calculations, applied to 3D X-ray computed tomography data, can yield quantitative information on the anisotropy of both meso-structure and fluid flow in Diesel Particulate Filter (DPF) materials, such as Cordierite and SiC. It was found that both the degree of anisotropy, and the orientation of the permeability and meso-structure are similar, but not identical. We confirm that the morphological anisotropy of cordierite materials is weak, and clearly influenced by the extrusion process that determines the main direction of anisotropy. Properties of the autocorrelation function are discussed and it is shown why estimating the characteristic length of real meso-structures (grain or ?pore? size) is not possible. Finally, we show that the autocorrelation function applied on grey-level images can give a good estimate of the degree of anisotropy even with limited resolution.
KW - Anisotropy
KW - Autocorrelation function
KW - Computed tomography
KW - Permeability tensor
KW - Diesel particulates filter
KW - Ceramics
PY - 2020
DO - https://doi.org/10.1080/14786435.2020.1798532
SN - 1478-6435
VL - 100
IS - 22
SP - 2802
EP - 2835
PB - Taylor & Francis
AN - OPUS4-52291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Micromechanics of internal stresses in multiphase materials, Part II- Mechanical properties of microcracked and porous materials
N2 - In this Seminar cycle I will present first diffraction methods to determine residual stress and investigate micromechanical properties of complex materials, and then particularize the treatment with applications to porous microcracked ceramics for diesel particulate filter applications.
I will show that neutron diffraction is particularly suited for bulk studies, where 3D stresses are needed. The advantages to use Time-of-Flight or steady state sources will be discussed, together with the problematic of the determination of absolute RS values.
Finally, the behavior of DPF materials under applied load or at high temperatures will be discussed under the combination of macroscopic and microscopic tests.
T2 - ATHOR webinar "Micromechanics of internal stresses in multiphase materials"
CY - Online meeting
DA - 26.01.2021
KW - Porosity
KW - Neutron Diffraction
KW - Residual Stress
KW - Non-linear stress-strain
KW - Anisotropy
KW - Microcracking
KW - Imaging
PY - 2021
AN - OPUS4-52126
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Assessing the safety of new technologies: Summary of Project AGIL
N2 - In Additive Manufacturing everybody is talking about Free Form, Unconventional Design, Re-thinking Components, “Think out of the box”.
However, there are a few outstanding question: a) What are the material properties ? They certainly differ from literature values for conventional materials; b) How about the microstructure? It is different from conventional materials. Does it stay so with ageing? How does it form? c) Do we properly take residual stress into account? We often blame them for our ignorance about failure scenarios. d) Do we apply tailored heat treatments? Very often, we follow conventional schedules…
This talk describes the summary of the efforts carried out within the BAM Project AGIL.
At BAM, we aimed to thoroughly investigate the microstructure and how it evolves as a function of load and temperature (service), to determine the material properties after different process and service conditions, to properly determine residual stress and the way it impacts mechanical properties and component performance, to properly quantify the impact of (unavoidable?) defects, and to determine heat treatments tailored to the process-specific material (stress relieve, microstructure homogenization etc.).
The Project AGIL was and is intimately coupled with the project ProMoAM, dealing with online monitoring of AM processes.
T2 - Workshop In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys
CY - Online meeting
DA - 19.04.2021
KW - Mechanical properties
KW - Additive manufacturing
KW - Residual Stress
KW - Microstructure
KW - Fatigue
KW - Creep
PY - 2021
AN - OPUS4-52581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khimich, M. A.
A1 - Prosolov, K. A.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Monforte, X.
A1 - Teuschl, A. H.
A1 - Slezak, P.
A1 - Ibragimov, E. A.
A1 - Saprykin, A. A.
A1 - Kovalevskaya, Z. G.
A1 - Dmitriev, A. I.
A1 - Bruno, Giovanni
A1 - Sharkeev, Y. P.
T1 - Advances in Laser Additive Manufacturing of Ti-Nb Alloys: From Nanostructured Powders to Bulk Objects
N2 - The additive manufacturing of low elastic modulus alloys that have a certain level of porosity for biomedical needs is a growing area of research. Here, we show the results of manufacturing of porous and dense samples by a laser powder bed fusion (LPBF) of Ti-Nb alloy, using two distinctive fusion strategies. The nanostructured Ti-Nb alloy powders were produced by mechanical alloying and have a nanostructured state with nanosized grains up to 90 nm. The manufactured porous samples have pronounced open porosity and advanced roughness, contrary to dense samples with a relatively smooth surface profile. The structure of both types of samples after LPBF is formed by uniaxial grains having micro- and nanosized features. The inner structure of the porous samples is comprised of an open interconnected system of pores. The volume fraction of isolated porosity is 2 vol. % and the total porosity is 20 vol. %. Cell viability was assessed in vitro for 3 and 7 days using the MG63 cell line. With longer culture periods, cells showed an increased cell density over the entire surface of a porous Ti-Nb sample. Both types of samples are not cytotoxic and could be used for further in vivo studies.
KW - Additive manufacturing
KW - Biomaterials
KW - Ti-Nb alloy
KW - Nanostructured powder
KW - Laser methods
KW - Powder methods
KW - Laser powder bed fusion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525344
DO - https://doi.org/10.3390/nano11051159
VL - 11
IS - 5
SP - 1159
PB - MDPI
AN - OPUS4-52534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peruzzi, N.
A1 - Galli, S.
A1 - Helmholz, H.
A1 - Kardjilov, N.
A1 - Krüger, D.
A1 - Markötter, Henning
A1 - Moosmann, J.
A1 - Orlov, D.
A1 - Prgomet, Z.
A1 - Willumeit-Römer, R.
A1 - Wennerberg, A.
A1 - Bech, M.
T1 - Multimodal ex vivo methods reveal that Gd-rich corrosion byproducts remain at the implant site of biodegradable Mg-Gd screws
N2 - Extensive research is being conducted on magnesium (Mg) alloys for bone implant manufacturing, due to their biocompatibility, biodegradability and mechanical properties. Gadolinium (Gd) is among the most promising alloying elements for property control in Mg alloy implants; however, its toxicity is contro- versial. Investigating Gd behavior during implant corrosion is thus of utmost importance. In this study, we analyzed the degradation byproducts at the implant site of biodegradable Mg-5Gd and Mg-10Gd implants after 12 weeks healing time, using a combination of different imaging techniques: histology, energy-dispersive x-ray spectroscopy (EDX), x-ray microcomputed tomography (μCT) and neutron μCT. The main finding has been that, at the healing time in exam, the corrosion appears to have involved only the Mg component, which has been substituted by calcium and phosphorus, while the Gd remains localized at the implant site. This was observed in 2D by means of EDX maps and extended to 3D with a novel application of neutron tomography. X-ray fluorescence analysis of the main excretory organs also did not reveal any measurable accumulation of Gd, further reinforcing the conclusion that very limited or no removal at all of Gd-alloy happened during degradation.
KW - Magnesium-gadolinium alloy
KW - Biodegradable implant
KW - Multimodal analysis
KW - Energy-dispersive x-ray spectroscopy
KW - Micro-computed tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535910
DO - https://doi.org/10.1016/j.actbio.2021.09.047
SN - 1742-7061
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-53591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sprengel, Maximilian
A1 - Ulbricht, Alexander
A1 - Evans, Alexander
A1 - Kromm, Arne
A1 - Sommer, Konstantin
A1 - Werner, Tiago
A1 - Kelleher, J.
A1 - Bruno, Giovanni
A1 - Kannengießer, Thomas
T1 - Towards the optimization of post-laser powder bed fusion stress-relieve treatments of stainless steel 316L
N2 - This study reports on the stress relaxation potential of stress-relieving heat treatments for laser powder bed fused 316L. The residual stress is monitored non-destructively using neutron diffraction before and after the heat treatment. Moreover, the evolution of the microstructure is analysed using scanning electron microscopy. The results show, that a strong relaxation of the residual stress is obtained when applying a heat treatment temperature at 900°C. However, the loss of the cellular substructure needs to be considered when applying this heat treatment strategy.
KW - Residual stress
KW - Additive manufacturing
KW - Neutron diffraction
KW - Projekt AGIL - Alterung additiv gefertigter metallischer Materialien und Komponenten
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536045
DO - https://doi.org/10.1007/s11661-021-06472-6
SN - 1543-1940
VL - 52
IS - 12
SP - 5342
EP - 5356
PB - Springer
CY - Boston
AN - OPUS4-53604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauzon, C.
A1 - Mishurova, Tatiana
A1 - Fischer, M.
A1 - Ahlström, J.
A1 - Fritsch, Tobias
A1 - Bruno, Giovanni
A1 - Hryha, Eduard
T1 - Impact of contour scanning and helium-rich process gas on performances of Alloy 718 lattices produced by laser powder bed fusion
N2 - Contour scanning and process gas type are process parameters typically considered achieving second order effects compared to first order factors such as laser power and scanning speed. The present work highlights that contour scanning is crucial to ensure geometrical accuracy and thereby the high performance under uniaxial compression of complex Alloy 718 lattice structures. Studies of X-ray computed tomography visualizations of as-built and compression-strained structures reveal the continuous and smooth bending and compression of the walls, and the earlier onset of internal contact appearance in the denser lattices printed with contour. In contrast, the effect of addition of He to the Ar process gas appears to have limited influence on the mechanical response of the lattices and their microstructure as characterized by electron backscattered diffraction. However, the addition of He proved to significantly enhance the cooling rate and to reduce the amount of the generated spatters as evidenced by in situ monitoring of the process emissions, which is very promising for the process stability and powder reusability during laser powder bed fusion.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Gyroid lattice
KW - Process atmosphere
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546632
DO - https://doi.org/10.1016/j.matdes.2022.110501
SN - 0264-1275
VL - 215
SP - 110501
PB - Elsevier Ltd.
AN - OPUS4-54663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Mieller, Björn
A1 - Mrkwitschka, Paul
A1 - Moos, R.
A1 - Rabe, Torsten
T1 - Glass-ceramic composites as insulation material for thermoelectric oxide multilayer generators
N2 - Thermoelectric generators can be used as energy harvesters for sensor applications.
Adapting the ceramic multilayer technology, their production can be
highly automated. In such multilayer thermoelectric generators, the electrical insulation material, which separates the thermoelectric legs, is crucial for the performance of the device. The insulationmaterial should be adapted to the thermoelectric regarding its averaged coefficient of thermal expansion α and its sintering temperature while maintaining a high resistivity.
In this study, starting from theoretical calculations, a glass-ceramic Composite material adapted for multilayer generators fromcalciummanganate and Calcium cobaltite is developed. The material is optimized towards an α of 11 × 10−6 K−1 (20–500◦C), a sintering temperature of 900◦C, and a high resistivity up to 800◦C.
Calculated and measured α are in good agreement. The chosen glass-ceramic composite with 45 vol.% quartz has a resistivity of 1 × 107 Ωcm and an open porosity of <3%. Sintered multilayer samples from tape-cast thermoelectric oxides and screen-printed insulation show only small reaction layers. It can be concluded that glass-ceramic composites are a well-suited material class for insulation layers as their physical properties can be tuned by varying glass composition or dispersion phases.
KW - Electrical insulators
KW - Glass-ceramics
KW - Multilayers
KW - Thermal expansion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538898
DO - https://doi.org/10.1111/jace.18235
SN - 0002-7820
SP - 1
EP - 10
PB - Wiley Online Library
AN - OPUS4-53889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Schaupp, Thomas
A1 - Griesche, Axel
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Hannemann, Andreas
A1 - Kannengießer, Thomas
A1 - Bruno, Giovanni
T1 - Quantitative analysis of hydrogen-assisted microcracking in duplex stainless steel through X-ray refraction 3D imaging
N2 - While the problem of the identification of mechanisms of hydrogen assisted damage has and is being thoroughly studied, the quantitative analysis of such damage still lacks suitable tools. In fact, while, for instance, electron microscopy yields excellent characterization, the quantitative analysis of damage requires at the same time large field-of-views and high spatial resolution. Synchrotron X-ray refraction techniques do possess both features. In this work, we show how synchrotron X-ray refraction computed tomography (SXRCT) can quantify damage induced by hydrogen embrittlement in a lean duplex steel, yielding results that overperform even those achievable by synchrotron X-ray absorption computed tomography. As already reported in literature, but this time using a non-destructive technique, we show that the hydrogen charge does not penetrate to the center of tensile specimens. By the comparison between virgin and hydrogen-charged specimens, we deduce that cracks in the specimen bulk are due to the rolling process rather than hydrogen-assisted. We show that (micro)cracks propagate from the surface of tensile specimens to the interior with increasing applied strain, and we deduce that a significant crack propagation can only be observed short before rupture.
KW - 2101 duplex stainless steel
KW - Hydrogen embrittlement
KW - Synchrotron radiation
KW - X-ray refraction
KW - Computed tomography
KW - Microcracking
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542811
DO - https://doi.org/10.1002/adem.202101287
SN - 1438-1656
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Artzt, K.
A1 - Haubrich, J.
A1 - Sevostianov, I.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Micromechanical behavior of annealed Ti-6Al-4V produced by Laser Powder Bed Fusion
N2 - The micromechanical behavior of an annealed Ti-6Al-4V material produced by Laser Powder Bed Fusion was characterized by means of in-situ synchrotron X-ray diffraction during a tensile test. The lattice strain evolution was obtained parallel and transversal to the loading direction. The elastic constants were determined and compared with the conventionally manufactured alloy. In the plastic regime, a lower plastic anisotropy exhibited by the lattice planes was observed along the load axis (parallel to the building direction) than in the transverse direction.
Also, the load transfer from α to β phase was observed, increasing global ductility of the material. The material seems to accumulate a significant amount of intergranular strain in the transverse direction.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Anisotropy
KW - Intergranular strain
KW - Synchrotron X-ray diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547406
DO - https://doi.org/10.1080/26889277.2022.2063763
VL - 2
IS - 1
SP - 186
EP - 201
PB - Taylor & Francis
AN - OPUS4-54740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Oster, Simon
A1 - Ulbricht, Alexander
A1 - Bruno, Giovanni
T1 - Review on image registration methods for the quality control in additive manufacturing
N2 - A critical challenge in Additive Manufacturing is to ensure the safety and dimensional accuracy of produced parts. Since quality control is made by means of different online and offline imaging techniques (e.g. Thermography, X-ray and Optical Computer Tomography), image registration plays an important role in addressing these challenges. This paper introduces the main motivation, challenges, and research gaps of image registration in Additive Manufacturing. Furthermore, it introduces the main transformations, registration methods, similarity matrices and accuracy measurement. The main aim of the paper is to present a comprehensive review on the available methods for image registration in Additive Manufacturing based on the measurement techniques. Various registration methods, including landmark-based, point cloud-based, image intensity-based, and shape-based techniques, are examined in their applications for quality control, defect detection, and distortion quantification.
KW - Image processing
KW - Image fusion
KW - Computed tomography
KW - Computer-aided design
KW - Additive manufacturing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624495
DO - https://doi.org/10.1007/s40964-024-00932-2
SN - 2363-9520
SP - 1
EP - 27
PB - Springer Science and Business Media LLC
AN - OPUS4-62449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Fritsch, Tobias
A1 - Ferrari, Bruno
A1 - Altmann, Mika León
A1 - Bruno, Giovanni
A1 - Toenjes, Anastasiya
T1 - Laser powder bed fusion: Defect type influences critical porosity re-growth during reheating after hot isostatic pressing
N2 - Despite the remarkable product design flexibility offered by additive manufacturing (AM) techniques, such as laser powder bed fusion, AM processes are susceptible to the formation of defects. In this context, the control of process parameters and the application of post-processing treatments, such as hot isostatic pressing (HIP), are of paramount importance to achieve the desired mechanical properties. The present study investigates the effectiveness of HIP as a function of process parameters in laser powder bed fused Ti-6V-4Al (PBF-LB/Ti64) using X-ray computed tomography. The process parameters are modified to obtain reference samples with low porosity, lack of fusion defects, or keyhole porosity. In all instances, subsurface keyhole porosity was observed in the as-built parts. Moreover, it was found that the efficacy of pore closure is dependent on the specific defect type. In the case of low porosity and keyhole pores, HIP resulted in effective closure. Conversely, larger lack of fusion defects were not closed due to their interconnectivity and the entrapment of argon gas. Subsequent heat treatments above the β-transus temperature allowed the investigation of the impact of defect type on porosity re-growth. For the first time, we reveal that lack of fusion defects are affected by considerable pore re-growth during post-HIP heat treatments of PBF-LB/Ti64. Such phenomenon is driven by the increasing internal pore pressure and local creep deformation at high temperatures. In contrast, re-growth is limited in samples with low porosity or keyhole pores.
KW - Additive Manufacturing
KW - Hot Isostatic Pressing
KW - Titanium
KW - Laser Powder Bed Fusion
KW - X-ray Computed Tomography
KW - Heat Treatment
KW - Porosity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629289
DO - https://doi.org/10.1016/j.jmatprotec.2025.118839
VL - 340
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-62928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Oster, Simon
A1 - Ulbricht, Alexander
A1 - Poka, Konstantin
A1 - Bruno, Giovanni
T1 - A Comparative Study of Rigid Three-Dimensional Image Registration Methods for Powder Bed Fusion with Laser Beam of Metals Using a Gold Standard Approach
N2 - In Additive Manufacturing (AM), precise rigid three-dimensional (3D) image registration between X-ray Computed Tomography (XCT) scans and Computer-Aided Design (CAD) models is an important step for the quantification of distortions in produced parts. Given the absence of standardized benchmarks for image registration in AM, we introduce a gold standard for 3D image registration, using a reference base plate beneath the build structure. This gold standard is used to quantify the accuracy of rigid registration, with a proof of concept demonstrated in PBF-LB/M. In this study, we conduct a comparative analysis of various rigid 3D registration methods useful for quality assurance of PBF-LB/M parts including feature-based, intensity-based, and point cloud-based approaches. The performance of each registration method is evaluated using measures of alignment accuracy based on the gold standard and computational efficiency. Our results indicate significant differences in the efficacy of these methods, with point cloud based Coherent Point Drift (CPD) showing superior performance in both alignment and computational efficiency. The rigidly registered 3D volumes are used to estimate the deformation field of the printed parts relative to the nominal CAD design using Digital Volume Correlation (DVC). The quality of the estimated deformation field is assessed using the Dice score metric. This study provides insights into methods for enhancing the precision and reliability of AM process.
KW - Digital volume correlation
KW - 3D image registration
KW - 3D image processing
KW - X-ray computed tomography
KW - Computer-aided design
KW - Displacement field estimation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627043
DO - https://doi.org/10.1007/s10921-025-01174-0
SN - 1573-4862
VL - 44
IS - 30
SP - 1
EP - 20
PB - Springer
AN - OPUS4-62704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fardan, Ahmed
A1 - Fazi, Andrea
A1 - Schröder, Jakob
A1 - Mishurova, Tatiana
A1 - Deckers, Tobias
A1 - Bruno, Giovanni
A1 - Thuvander, Matthias
A1 - Markström, Andreas
A1 - Brodin, Hakan
A1 - Hryha, Eduard
T1 - Microstructure tailoring for crack mitigation in CM247LC manufactured by powder bed fusion – Laser beam
N2 - Tailored microstructures in powder bed fusion – laser beam (PBF-LB) can aid in crack mitigation of non-weldable Ni-base superalloys such as CM247LC. This study explores the effect of a range of stripe widths from 5 mm down to 0.2 mm to control solidification cracking, microstructure, and residual stress in CM247LC manufactured by PBF-LB. The decrease in melt pool depth with the reduction in stripe width from 5 to 0.2 mm promoted the < 100 > crystallographic texture along the build direction. The crack density measurements indicated that there is an increase from 0.62 mm/mm2 (5 mm) to 1.71 mm/mm2 (1 mm) followed by a decrease to 0.33 mm/mm2 (0.2 mm). Atom probe tomography investigations at high-angle grain boundaries revealed that there is higher Hf segregation in 0.2 mm stripe width when compared to 5 mm. This indicates that the cracking behavior is likely influenced by the grain boundary segregation which in turn is dependent on melt pool shape/size and mushy zone length indicated by accompanying simulations. Residual stress, measured by X-ray diffraction, decreased from 842 MPa (5 mm) to 690 MPa (1 mm), followed by an abnormal rise to 842 MPa (0.7 mm) and 875 MPa (0.5 mm). This residual stress behavior is likely associated with the cracks acting as a stress relief mechanism. However, the 0.2 mm stripe width exhibited the lowest stress of 647 MPa, suggesting a different mechanism for stress relief, possibly due to re-melting. These findings highlight the critical role of stripe width as a scan strategy in PBF-LB processing of crack-susceptible alloys.
KW - Additive manufacturing
KW - Residual stress
KW - Scanning strategy
KW - Non-weldable superalloy
KW - Solidification cracking
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624606
DO - https://doi.org/10.1016/j.addma.2025.104672
SN - 2214-7810
VL - 99
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-62460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Malladi, Sri Bala Aditya
A1 - Mishurova, Tatiana
A1 - Anilkumar, Vishnu
A1 - Mehta, Bharat
A1 - Evans, Alexander
A1 - Surreddi, Kumar Babu
T1 - Reducing plastic anisotropy through stress induced martensitic transformation in an additively manufactured metastable medium entropy alloy
N2 - Powder bed fusion laser beam (PBF-LB) is particularly effective for fabricating compositionally complex alloys such as high-entropy alloys (HEAs) or medium-entropy alloys (MEAs). Fabricating non-equiatomic metastable MEAs using PBF-LB can lead to the formation of unique microstructures that enhance the mechanical performance of these alloys. Nevertheless, plastic anisotropy in materials prepared by additive manufacturing routes including PBF-LB remains to be a technical challenge. This work presents the fabrication of a metastable non-equiatomic Co45Cr25(FeNi)30 MEA using PBF-LB. As-printed samples exhibited the formation of nano-scaled ε-martensite (HCP) phase along with the FCC phase. The HCP phase exhibited Shoji-Nishiyama orientation relationship with the FCC phase. High energy synchrotron X-ray diffraction (HEXRD) and electron backscatter diffraction (EBSD) in-situ tensile testing were employed to investigate the influence of the HCP phase on the alloy's deformation behavior. The presence of the HCP phase initiates stress-induced martensitic transformation well below the macroscopic yield strength. This transformation led to the non-linear stress and strain response for the FCC phase. Further straining resulted in significant load partitioning, with the HCP phase taking the majority of the load as it formed, significantly strain hardening the alloy and reducing the plastic anisotropy induced by texture in the as-printed material.
KW - Neutron Diffraction
KW - X-ray computed tomography
KW - Mechanical Properties
KW - Additive Manufacturing
KW - Residual stress
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630588
DO - https://doi.org/10.1016/j.msea.2025.148308
SN - 1873-4936
VL - 933
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-63058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, M.
A1 - Tsamos, Athanasios
A1 - Faglion, F.
A1 - Fioresi, R.
A1 - Zanchetta, F.
A1 - Bruno, Giovanni
T1 - Vision GNN (ViG) architecture for a fine‑tuned segmentation of a complex Al–Si metal matrix composite XCT volume
N2 - In this paper, we implement a vision graph neural network (ViG) architecture to segment microstructures in X-ray computed tomography 3D data. Our ViG architecture is first trained on a synthetic augmented dataset, and then fine-tuned on experimental data to obtain an improved segmentation. Successively, we assess the accuracy of the segmentation on manually-labeled experimental slices. We exemplarily use the approach on a complex microstructure: a metal matrix composite, reinforced with two ceramic phases, intermetallic inclusions and a silicon network, in order to show the generality of our method. ViG model proves to be more efficient than U-Nets in adapting to new data when fine-tuned on a small portion of the experimental data. The fine-tuned ViG shows comparable performance to U-Nets, while largely reducing the number of trainable parameters, with the potential of greater adaptability and efficiency.
KW - X-ray Computed tomography
KW - Machine Learning
KW - Virtual XCT
KW - Segmentation
KW - Composites
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630593
DO - https://doi.org/10.1007/s10853-025-10834-5
SN - 1573-4803
VL - 60
SP - 6907
EP - 6921
PB - Springer
AN - OPUS4-63059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rahimi, A.
A1 - Coduri, M.
A1 - Fitch, A.
A1 - Vedani, M.
A1 - Schröder, J.
A1 - Bruno, Giovanni
A1 - Casati, R.
T1 - Synchrotron investigation of heat treatment effects on the 3D residual stress distribution in laser powder bed fused AlSi7Mg alloys
N2 - For the first time, we utilized synchrotron diffraction to determine 3D maps of residual stresses across the entire volume of thick AlSi7Mg alloy prisms produced by PBF-LB. Samples were subjected to different heat treatment processes: direct aging (T5), solution treatment, and solution treatment followed by aging (T6). The T6 heat treatment resulted in the lowest residual tensile strains, while the T5 treatment resulted in significantly higher residual strains. Maximum residual stresses decreased from the as-built condition to the T6 heat-treated specimen. Although the T5 condition provides greater strength, it also retains higher tensile residual stresses near the surface, which can negatively affect fatigue properties.
KW - Neutron Diffraction
KW - Residual Stress
KW - Large Scale Facilities
KW - Additive Manufacturing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631089
DO - https://doi.org/10.1016/j.matlet.2025.138742
SN - 0167-577X
VL - 396
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-63108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tran, K. V.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Hilger, A.
A1 - Kockelmann, W.
A1 - Kelleher, J.
A1 - Puplampu, S. B.
A1 - Penumadu, D.
A1 - Tremsin, A. S.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Spectral neutron tomography
N2 - Combined three-dimensional (3D) mapping of (micro-)structures with elemental and crystalline phase variations is of significant importance for the characterization of materials. Neutron wavelength selective imaging is a spectral imaging technique that exploits unique contrast differences e.g. for mapping dissimilar elemental, isotope, or phase compositions, and has the particular advantage of being applicable to sample volumes on the meso- and macroscale. While being mostly applied as radiography (2D) so far, we herein report that the extension to tomography allows for the display of the full spectral information for every voxel and in 3D. The development is supported by example data from a continuous as well as a pulsed neutron source. As a practical example, we collected 4D data sets (3D + spectral) of plastically deformed metastable stainless steel and herein demonstrate an improved quantification strategy for crystalline phase fractions. These exemplary results illustrate that localized phase transformations can be quantified even in complex geometries within centimeter-sized samples, and we will discuss the limits and future prospects of the technique that is not limited to crystalline materials.
KW - 4D tomographic data
KW - Multi-energy CT
KW - Spectral CT
KW - Phase distribution
KW - Full-field phase tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521668
DO - https://doi.org/10.1016/j.mtadv.2021.100132
VL - 9
SP - 132
PB - Elsevier Ltd.
AN - OPUS4-52166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Mieller, Björn
A1 - Schönauer-Kamin, D.
A1 - Moos, R.
A1 - Reimann, T.
A1 - Giovannelli, F.
A1 - Rabe, Torsten
T1 - Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite
N2 - Calcium cobaltite Ca3Co4O9, abbreviated Co349, is a promising thermoelectric material for high‐temperature applications in air. Its anisotropic properties can be assigned to polycrystalline parts by texturing. Tape casting and pressure‐assisted sintering (PAS) are a possible future way for a cost‐effective mass‐production of thermoelectric generators. This study examines the influence of pressure and dwell time during PAS at 900°C of tape‐cast Co349 on texture and thermoelectric properties. Tape casting aligns lentoid Co349. PAS results in a textured Co349 microstructure with the thermoelectrically favorable ab‐direction perpendicular to the pressing direction. By pressure variation during sintering, the microstructure of Co349 can be tailored either toward a maximum figure of merit as required for energy harvesting or toward a maximum power factor as required for energy harvesting. Moderate pressure of 2.5 MPa results in 25% porosity and a textured microstructure with a figure of merit of 0.13 at 700°C, two times higher than the dry‐pressed, pressureless‐sintered reference. A pressure of 7.5 MPa leads to 94% density and a high power factor of 326 µW/mK2 at 800°C, which is 11 times higher than the dry‐pressed reference (30 MPa) from the same powder.
KW - Hot pressing
KW - Texture
KW - Thermoelectric properties
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515973
DO - https://doi.org/https://doi.org/10.1111/jace.17541
SN - 0002-7820
VL - 104
IS - 2
SP - 917
EP - 927
PB - Wiley Periodicals LLC
AN - OPUS4-51597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Altenburg, Simon
A1 - Sprengel, Maximilian
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Fritsch, Tobias
A1 - Mishurova, Tatiana
A1 - Serrano-Munoz, Itziar
A1 - Evans, Alexander
A1 - Hofmann, M.
A1 - Bruno, Giovanni
T1 - Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L
N2 - Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - LPBF
KW - AISI 316L
KW - Online Process Monitoring
KW - Thermography
KW - Residual Stress
KW - Neutron Diffraction
KW - X-ray Diffraction
KW - Computed Tomography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512903
DO - https://doi.org/10.3390/met10091234
VL - 10
IS - 9
PB - MDPI
CY - Basel
AN - OPUS4-51290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Höhne, Patrick
A1 - Mieller, Björn
A1 - Rabe, Torsten
T1 - Advancing spray granulation by ultrasound atomization
N2 - The influence of the atomization technique on the suitability of granules for dry pressing is the focus of the presented investigations. Therefore, destabilized alumina, zirconia, and zirconia toughened alumina (ZTA) slurries were spray dried and the obtained granules were used to fabricate green and finally sintered bodies for evaluation.
Granules made in a laboratory spray dryer with a two-fluid nozzle served as a reference. An ultrasonic atomizer was integrated into the same spray dryer and the influence on the granule properties was evaluated. Untapped bulk density, granule size distribution, and flowability are among the evaluated granule-related properties as well as the granule yield which is used as an indicator of the process efficiency.
Yield and flowability as most important granule properties are clearly improved when atomization is realized with ultrasound. The investigated sinter body properties include porosity, sinter body density, and biaxial strength and are as well positively affected by switching the atomization technique to ultrasound. Therefore, the Approach to improve the compressibility of granules by ultrasonic atomization, which leads to an improved microstructure, density, and strength of sintered bodies, has proven to be successful for single-component ceramics (alumina and zirconia) as well as for the multicomponent ceramic ZTA.
KW - Alumina
KW - Granules
KW - Spray drying
KW - Ultrasound
KW - Zirconia
KW - Zirconia-toughened alumina
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510696
DO - https://doi.org/10.1111/ijac.13534
VL - 17
IS - 5
SP - 2212
EP - 2219
AN - OPUS4-51069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Trappe, Volker
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging
N2 - Modern air-liners and wind turbine rotor blades are made up primarily of fiber reinforced plastics. Failure of these materials heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in situ non-destructive testing techniques. Here, we report in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics due to inter-fiber failure. An inhouse designed compact tensile testing machine with a load range up to 15 kN was integrated into the beamline. Since conventional radiographs do not reveal sufficient contrast to distinguish cracks due to inter-fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging (DEI) technique is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. This technique allows fast measurements over large fields-of-view and is ideal for in-situ investigations. Imaging and the tensile test are run at the highest possible frame rate (0.7 s-1 ) and the lowest possible strain rate (5.5∙10-4 s -1 ). For 0°/90° non-crimp fabrics, the first inter-fiber cracks occur at 380 MPa (strain 0.8 %). Prior to failure at about 760 MPa (strain 2.0 %), we observe the evolution of nearly equidistant (1 mm distance) cracks running across the entire sample in the fully damaged state.
KW - X-ray refraction
KW - Diffraction Enhanced Imaging
KW - Carbon Fiber Reinforced Plastics
KW - In situ tensile test
KW - Crack evolution
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515060
DO - https://doi.org/10.1088/1757-899X/942/1/012035
SN - 1757-8981
SN - 1757-899X
VL - 942
SP - 012035-1
EP - 012035-9
PB - IOP publishing
CY - Bristol, UK
AN - OPUS4-51506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Schob, D.
A1 - Léonard, Fabien
A1 - Müller, Bernd R.
A1 - Sagradov, I.
A1 - Roszak, R.
A1 - Sparr, H.
A1 - Franke, R.
A1 - Ziegenhorn, M.
A1 - Bruno, Giovanni
T1 - Bestimmung der Mikrostruktur und Simulation des Schädigungsverhaltens von lasergesintertem Polyamid 12 unter quasistatischer Zugbelastung
N2 - Um das Material- und Schädigungsverhalten von additiv gefertigtem Polyamid 12 (PA12) unter quasistatischer Belastung zu charakterisieren, wurden mechanische Tests und Röntgenverfahren zur Bestimmung der Mikrostruktur eingesetzt. Die Proben wurden nach dem Prinzip des Selektiven Lasersinterns (SLS) hergestellt. Unter quasistatischer Belastung mit Haltezeiten ergab sich ein viskoplastisches Materialverhalten. Im Zugversuch wurde eine maximale Zugfestigkeit von 40.6 MPa und eine Bruchdehnung von 7.4% beobachtet. Mittels Röntgenrefraktion wurde eine Erhöhung von inneren Oberflächen beobachtet, die senkrecht zur Zugrichtung orientiert sind. Die Analyse der Gesamtporosität aus Computertomographie-Messungen ergab keine Änderung infolge der Zugbelastung. Jedoch wurde eine bimodale Porengrößenverteilung und eine steigende Sphärizität festgestellt. Das Materialverhalten wurde mit dem Chaboche-Modell simuliert und ergab eine sehr gute Übereinstimmung mit den experimentellen Ergebnissen. Allerdings gestattet dieses Modell nicht, das Schädigungsverhalten abzubilden. Daher wurde zur Simulation des Schädigungsverhaltens das Modell gemäß dem Ansatz von Gurson, Tvergaard und Needleman unter Berücksichtigung der mikrostrukturellen Parameter erweitert. Der Schwerpunkt des Beitrags liegt auf den Röntgenverfahren zur experimentellen Bestimmung der Mikrostruktur.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Additive Fertigung (AM)
KW - Polyamid 12
KW - Röntgenrefraktion
KW - Computertomographie
KW - Numerische Simulation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526833
UR - https://jahrestagung.dgzfp.de/Portals/jt2021/bb/P16.pdf
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-52683
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
T1 - Brittle Materials in Mechanical Extremes
N2 - The goal of the Special Issue “Brittle Materials in Mechanical Extremes” was to spark a discussion of the analogies and the differences between different brittle materials, such as, for instance, ceramics and concrete. Indeed, the contributions to the Issue spanned from construction materials (asphalt and concrete) to structural ceramics, reaching as far as ice. The data shown in the issue were obtained by advanced microstructural techniques (microscopy, 3D imaging, etc.) and linked to mechanical properties (and their changes as a function of aging, composition, etc.). The description of the mechanical behavior of brittle materials under operational loads, for instance, concrete and ceramics under very high temperatures, offered an unconventional viewpoint on the behavior of brittle materials. This is not at all exhaustive, but a way to pave the road for intriguing and enriching comparisons.
KW - Microcracking
KW - Ceramics
KW - Concrete
KW - Asphalt
KW - Mechanicalproperties
KW - Microstructure
KW - Strength
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514558
DO - https://doi.org/10.3390/ma13204610
VL - 13
IS - 20
SP - 4610
PB - MDPI
CY - Basel
AN - OPUS4-51455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markötter, Henning
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Evsevleev, Sergei
A1 - Arlt, T.
A1 - Ulbricht, Alexander
A1 - Dayani, Shahabeddin
A1 - Bruno, Giovanni
T1 - A Review of X-Ray Imaging at the BAMline (BESSY II)
N2 - The hard X-ray beamline BAMline at BESSY II (Berlin, Germany) has now been in service for 20 years. Several improvements have been implemented in this time, and this review provides an overview of the imaging methods available at the BAMline. Besides classic full-field synchrotron X-ray computed tomography (SXCT), also absorption edge CT, synchrotron X-ray refraction radiography (SXRR), and synchrotron X-ray refraction tomography (SXRCT) are used for imaging. Moreover, virtually any of those techniques are currently coupled in situ or operando with ancillary equipment such as load rigs, furnaces, or potentiostats. Each of the available techniques is explained and both the current and the potential usage are described with corresponding examples. The potential use is manifold, the examples cover organic materials, composite materials, energy-related materials, biological samples, and materials related to additive manufacturing. The article includes published examples as well as some unpublished applications.
KW - Material science
KW - Radiography
KW - Refraction
KW - Tomography
KW - X-ray imaging
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572417
DO - https://doi.org/10.1002/adem.202201034
SN - 1438-1656
SP - 1
EP - 22
PB - Wiley VHC-Verlag
AN - OPUS4-57241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mouiya, M.
A1 - Martynyuk, M.
A1 - Kupsch, Andreas
A1 - Laquai, R.
A1 - Müller, Bernd R.
A1 - Doyen, N.T.
A1 - Tamraoui, Y.
A1 - Serrano-Munoz, Itziar
A1 - Huger, M.
A1 - Kachanov, M.
A1 - Bruno, Giovanni
T1 - The stress–strain behavior of refractory microcracked aluminum titanate: The effect of zigzag microcracks and its modeling
N2 - The stress–strain behavior of ceramics, such as aluminum titanate, has certain features that are unusual for brittle materials—in particular, a substantial nonlinearity under uniaxial tension, and load–unload hysteresis caused by the sharp increase of the incremental stiffness at the beginning of unloading. These features are observed experimentally and are attributed to microcracking. Here we compare different degrees of stress–strain nonlinearity of aluminum titanate materials and quantitatively model them. We use advanced mechanical testing to observe the mechanical response at room and high temperature; electron microscopy, and X-ray refraction radiography to observe the microstructural changes. Experiments show that two types of microcracks can be distinguished: (i) microcracks induced by cooling from the sintering temperature (due to heterogeneity and anisotropy of thermal expansion), with typical sizes of the order of grain size, and (ii) much larger microcracks generated by the mechanical loading. The two microcrack types produce different effects on the stress–strain curves. Such microcracks and the features of the stress–strain behavior depend on the density of the cooling-induced microcracks and on the distribution of grain sizes. They are modeled analytically and numerically.
KW - Hystersis
KW - Nonlinear stress-strain curve
KW - Refractory
KW - Stiffness
KW - X-ray refraction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580517
DO - https://doi.org/10.1111/jace.19325
SN - 1551-2916
VL - 106
SP - 6995
EP - 7008
PB - Wiley-Blackwell
CY - Oxford [u.a.]
AN - OPUS4-58051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Serrano-Munoz, Itziar
A1 - Laquai, René
A1 - Bruno, Giovanni
T1 - Anwendungen der Röntgenrefraktionstechnik zur zerstörungsfreien Charakterisierung von Keramiken und Verbundwerkstoffen
N2 - Die Brechung von Röntgenstrahlen (Röntgenrefraktion) an Grenzflächen zwischen Materialien unterschiedlicher Dichte ist analog zur Ablenk-ung von sichtbarem Licht an z.B. Glasoberflächen. Es gibt jedoch zwei wesentliche Unterschiede:
a) konvexe Grenzflächen verursachen Divergenz (d.h. der Brechungsindex n ist kleiner als 1), und
b) die Ablenkungswinkel sind sehr klein, und reichen von einigen Bogensekunden bis zu einigen Bogenminuten (d.h. n ist nahe bei 1);
Wie auch bei sichtbarem Licht ist die Ablenkungsrichtung der Röntgenstrahlen abhängig von der Orientierung der durchstrahlten Grenzfläche. Aufgrund dieser Eigenschaften eignen sich Röntgenrefraktionsmethoden hervorragend für:
a) die Erkennung und Quantifizierung von Defekten wie Poren und Mikrorissen und
b) die Bewertung von Porosität und Partikeleigenschaften wie Orientierung, Größe und räumliche Verteilung.
Wir zeigen die Anwendung der Röntgenrefraktionsradiographie (2,5D Technik) und der -tomographie (3D Technik) für die Untersuchung verschiedener Probleme in der Werkstoffwissenschaft und -technologie:
a) Sintern von SiC-Grünkörpern
b) Porositätsanalyse in Dieselpartikelfiltersilikaten
c) Faser-Matrix-Haftung in Metall- und Polymermatrixverbundwerkstoffen
d) Mikrorissbildung in Glaskeramik.
Wir zeigen, dass der Einsatz von Röntgenrefraktionsmethoden quantitative Ergebnisse liefert, die direkt als Parameter in Werkstoffmodellen verwendet werden können.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Röntgen-Refraktion
KW - Verbundwerkstoffe
KW - Keramik
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576171
UR - https://jahrestagung.dgzfp.de/Portals/jt2023/BB180/Inhalt/p9.pdf
UR - https://jahrestagung.dgzfp.de/Portals/jt2023/BB180/Inhalt/default.htm
SN - 978-3-947971-29-9
SP - 1
EP - 16
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-57617
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Piault, Pierre
A1 - King, Andrew
A1 - Henry, Laura
A1 - Bruno, Giovanni
T1 - Understanding the hot isostatic pressing efectiveness of laser powder bed fusion Ti‑6Al‑4V by in‑situ X‑ray imaging and difraction experiments
N2 - In the present study, in-situ observation of Hot Isostatic Pressure (HIP) procedure of laser powder bed fusion manufactured Ti-6Al-4V parts was performed to quantitatively estimate the densifcation rate of the material and the infuence of the defect initial size and shape on such rate. The observations were performed in-situ using the Ultrafast Tomography Paris-Edinburgh Cell and the combination of fast phase-contrast synchrotron X-ray tomography and energy dispersive difraction. With this strategy, we could quantify how the efectiveness of HIP depends on the characteristics of a defect. Smaller defects showed a higher densifcation rate, while the defect shape did not have signifcant efect on such rate.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - X-ray computed tomography
KW - Hot isostatic pressing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587702
DO - https://doi.org/10.1038/s41598-023-45258-1
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 11
AN - OPUS4-58770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernández, R.
A1 - Bokuchava, G.
A1 - Bruno, Giovanni
A1 - Serrano-Munoz, Itziar
A1 - González Doncel, G.
T1 - On the dependence of creep-induced dislocation configurations on crystallographic orientation in pure Al and Al-Mg
N2 - The peak broadening in neutron diffraction experiments on tensile specimens of pure Al (99.8%) and an Al-Mg alloy pre-deformed at different creep strains is analysed. These results are combined with the kernel angular misorientation of electron backscatter diffraction data from the creep-deformed microstructures. It is found that differently oriented grains possess different microstrains. These microstrains vary with creep strain in pure Al, but not in the Al-Mg alloy. It is proposed that this behaviour can explain the power-law breakdown in pure Al and the large creep strain observed in Al-Mg. The present findings further corroborate a description of the creep-induced dislocation structure as a fractal, predicated on previous work.
KW - Creep
KW - Aluminium alloys
KW - Dislocations
KW - Fractals
KW - Diffraction peak width
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575527
DO - https://doi.org/10.1107/S1600576723003771
SN - 0021-8898
VL - 56
IS - Pt 3
SP - 764
EP - 775
AN - OPUS4-57552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Trappe, Volker
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Rissentwicklung in CFK-Laminaten nachgewiesen durch in situ Röntgen-Refraktion
N2 - In Leichtbauanwendungen sind Materialien mit geringen Dichten und hohen Festigkeiten gefragt. Insbesondere Faser-Kunststoff-Verbunde (FKV) erfüllen diese Anforderungen und werden zunehmend für Strukturbauteile eingesetzt. Die Oberflächen moderner Rotorblätter von Windkraftanlagen werden aus FKV gefertigt. Das Versagen dieser Materialien hat massiven Einfluss auf die Einsatzfähigkeit der gesamten Windkraftanlage. Daher ist die Kenntnis des Versagensverhaltens dieser Komponenten unter statischer und zyklischer Belastung von großem Interesse, um die Betriebsbeanspruchung abzuschätzen. Im Idealfall wird die Schadensentwicklung unter Betriebslast mit zerstörungsfreien in-situ-Prüfverfahren ermittelt. Hier berichten wir über die Beobachtung der Rissentwicklung in Carbon-Faserverstärkten Kunststoffen (CFK) unter kontinuierlicher Zugbelastung durch in-situ Synchrotron-Röntgenrefraktionsradiographie. Eine selbst entwickelte elektromechanische Zugprüfmaschine mit einem Kraftbereich bis zu 15 kN wurde in den Strahlengang an der BAMline (BESSY II) integriert. Da in herkömmlichen (Absorptions-) Radiographien Defekte wie Zwischenfaserbrüche oder Faser-Matrix-Enthaftung keinen ausreichenden Kontrast verursachen, wird zur Kontrastanhebung die Röntgenrefraktion benutzt. Hier wird das sogenannte Diffraction Enhanced Imaging (DEI) angewandt, um Primär- und gebrochene Strahlung mit Hilfe eines Analysatorkristalls zu trennen. Diese Technik ermöglicht schnelle Messungen mit einem Gesichtsfeld von einigen Quadratmillimetern (hier: 14 mm × 7.2 mm) und ist ideal für in-situ Untersuchungen. Die Bildgebung und der Zugversuch erfolgen mit einer Bildfrequenz von 0.7 / s und einer Dehnrate von 0.00055 / s . Bei 0°/90° Fasergelegen treten die ersten Zwischenfaserrisse bei 380 MPa (Dehnung 0.8 %) auf. Vor dem Versagen bei ca. 760 MPa (Dehnung 2.0 %) beobachten wir die Ausbildung eines nahezu äquidistanten Rissmusters (Risse in ca. 1 mm Abstand), das sich im geschädigten Zustand über die gesamte Probe erstreckt.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Röntgen-Refraktion
KW - Synchrotronstrahlung
KW - CFK
KW - Rissentwicklung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576230
SN - 978-3-947971-29-9
VL - BB 180
SP - 1
EP - 8
AN - OPUS4-57623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nadammal, Naresh
A1 - Mishurova, Tatiana
A1 - Fritsch, Tobias
A1 - Serrano-Munoz, Itziar
A1 - Kromm, Arne
A1 - Haberland, C.
A1 - Portella, Pedro Dolabella
A1 - Bruno, Giovanni
T1 - Critical role of scan strategies on the development of microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing
N2 - Laser based powder bed fusion additive manufacturing offers the flexibility to incorporate standard and userdefined scan strategies in a layer or in between the layers for the customized fabrication of metallic components. In the present study, four different scan strategies and their impact on the development of microstructure, texture, and residual stresses in laser powder bed fusion additive manufacturing of a nickel-based superalloy Inconel 718 was investigated. Light microscopy, scanning electron microscopy combined with electron backscatter diffraction, and neutron diffraction were used as the characterization tools. Strong textures with epitaxially grown columnar grains were observed along the build direction for the two individual scan strategies. Patterns depicting the respective scan strategies were visible in the build plane, which dictated the microstructure development in the other planes. An alternating strategy combining the individual strategies in the successive layers and a 67◦ rotational strategy weakened the texture by forming finer microstructural features. Von Mises equivalent stress plots revealed lower stress values and gradients, which translates as lower distortions for the alternating and rotational strategies. Overall results confirmed the scope for manipulating the microstructure, texture, and residual stresses during laser powder bed fusion additive manufacturing by effectively controlling the scan strategies.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Nickel-based superalloys
KW - Scan strategies
KW - Residual stresses
KW - Microstructure and texture
PY - 2021
DO - https://doi.org/10.1016/j.addma.2020.101792
VL - 38
SP - 1792
PB - Elsevier B.V.
AN - OPUS4-51944
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Hejazi, Bardia
A1 - Poka, Konstantin
A1 - Bruno, Giovanni
T1 - Deep Learning Based 3D Volume Correlation for Additive Manufacturing Using High-Resolution Industrial X-Ray Computed Tomography
N2 - Quality control in Additive Manufacturing (AM) is vital for industrial applications in areas such as the automotive, medical, and aerospace sectors. Geometric inaccuracies caused by shrinkage and deformations can compromise the life and performance of additively manufactured components. Such deviations can be quantified using Digital Volume Correlation (DVC), which compares the Computer-Aided Design (CAD) model with the X-ray Computed Tomography (XCT) geometry of the components produced. However, accurate registration between the two modalities is challenging due to the absence of a ground truth or reference deformation field. In addition, the extremely large data size of high-resolution XCT volumes makes computation difficult. In this work, we present a deep learning-based approach for estimating voxel-wise deformations between CAD and XCT volumes. Our method uses a dynamic patch-based processing strategy to handle high-resolution volumes. In addition to the Dice score, we introduce a Binary Difference Map (BDM) that quantifies voxel-wise mismatches between binarized CAD and XCT volumes to evaluate the accuracy of the registration. Our approach shows a 9.2% improvement in the Dice score and a 9.9% improvement in the voxel match rate compared to classic DVC methods, while reducing the interaction time from days to minutes. This work sets the foundation for deep learning-based DVC methods to generate compensation meshes that can then be used in closed-loop correlations during the AM production process. Such a system would be of great interest to industry, as it would make the manufacturing process more reliable and efficient, saving time and material.
KW - Deep learning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646293
DO - https://doi.org/10.3233/FAIA251475
SN - 0922-6389
VL - 413
SP - 5368
EP - 5375
PB - IOS Press
AN - OPUS4-64629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Isaac, Augusta
A1 - Serrano‐Munoz, Itziar
A1 - Kostka, Aleksander
A1 - Widjaja, Martinus Putra
A1 - González‐Doncel, Gaspar
A1 - Bruno, Giovanni
A1 - Fernández, Ricardo
T1 - Subgrain and Cavity Development during Creep of Al‐3.85%Mg
N2 - It is classically considered that the creep mechanisms for type M (e.g., pure Al) and type A alloys (e.g., Al–Mg alloys) are different. In previous studies, it is predicated that fractal dislocation structures build up during creep can unify the creep behavior of pure Al and Al–Mg alloys. So far, good agreement between model and experimental data for pure Al is obtained. In this work, an Al‐3.85%Mg material crept at different strain levels (6%, 12%, 24%, and 35%) is analyzed by means of electron channelling contrast imaging. The formation of subgrains is observed at very large deformations (35%). Further examinations at 35% deformation, using electron backscatter diffraction, indicate that the subgrains and cavities tend to localize at regions where high intergranular stress mismatch is expected to occur. Laboratory X‐ray computed tomography is used to analyze the evolution of cavities between 12% and 24% stages, indicating that the fractal dimension of the cavities smaller than 100 μm varies with creep strain, as a reflection of the evolution of dislocation distribution. It is explained how the present data feed the model of the creep behavior of Al‐3.85%Mg.
KW - Al–Mg alloys
KW - Creep
KW - Dislocations
KW - Fractal
KW - Intergranular residual stress
KW - Subgrains
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645905
DO - https://doi.org/10.1002/adem.202500263
SN - 1438-1656
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-64590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Campos de Oliveira, Paula
A1 - Markötter, Henning
A1 - Zhang, Wen
A1 - Eddah, Mustapha
A1 - Widjaja, Martinus Putra
A1 - Remacha, Clément
A1 - Bruno, Giovanni
T1 - Enhanced image segmentation of refractories using synchrotron X-ray computed tomography and machine learning techniques
N2 - The microstructure of refractory materials is complex, featuring a variety of mineral phases, agglomerates, defects, and controlled porosity. The behavior of refractories at high temperatures adds another layer of complexity, as phase transitions and particle rearrangements can strongly affect their properties. To analyze such intricate microstructure, advanced imaging techniques such as Synchrotron X-ray Computed Tomography (SXCT) allow detailed 3D visualization and quantification of features up to 1 μm. However, the intricacy of these microstructures makes phase identification (known as image segmentation) in digital images a challenging process. X-ray images often contain noise and image artifacts, making the analysis more difficult. Therefore, this work describes image segmentation and artifact reduction methods to characterize refractories using X-ray imaging. We studied refractory ceramics used in the aerospace industry, primarily composed of fused silica. For image segmentation, the traditional approach of greyscale thresholding was compared with machine learning. Greyscale thresholding relies on predefined algorithms to assign phases based on intensity values. In contrast, machine learning extracts patterns from large datasets, enabling more adaptive and accurate segmentation. By combining high-resolution SXCT and machine learning analysis algorithms, we successfully segmented previously uncharacterized 3D microstructural key features of refractories, including agglomerates, grain boundaries, pore size distribution and interconnectivity. Compared to traditional methods, the machine learning-enhanced segmentation presented a more accurate quantification of porosity and defects. The integration of advanced imaging techniques with machine learning segmentation significantly improves the characterization of refractory materials, providing a more precise understanding of the relationship between microstructure and material performance, supporting the development of innovative industrial solutions.
T2 - The 19th Biennial International Technical Conference on Refractories (UNITECR 2025)
CY - Cancún, Mexiko
DA - 27.10.2025
KW - Synchrotron X-ray Tomography
KW - Machine learning
KW - Image segmentation
KW - Ceramics
KW - Refractories
PY - 2025
SP - 478
EP - 481
AN - OPUS4-64803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Röntgen-Computertomographie-Verfahren zur quantitativen Charakterisierung periodischer Minimalflächenstrukturen (TMPS)
N2 - Additiv gefertigte (AM) dreifach periodische metallische minimale Oberflächenstrukturen (TPMSS, aus dem Englischen Triply Periodic Minimum Surface Structures) erfüllen mehrere Anforderungen sowohl im biomedizinischen als auch im technischen Bereich: Abstimmbare mechanische Eigenschaften, geringe Empfindlichkeit gegenüber Herstellungsfehlern, mechanische Stabilität und hohe Energieabsorption. Allerdings stellen sie auch einige Herausforderungen in Bezug auf die Qualitätskontrolle dar, die ihre erfolgreiche Anwendung verhindern können. Tatsächlich ist die Optimierung des AM-Prozesses ohne die Berücksichtigung struktureller Merkmale wie Fertigungsgenauigkeit, interne Defekte sowie Oberflächentopographie und -rauheit unmöglich. In dieser Studie wurde die quantitative zerstörungsfreie Analyse von Ti-6Al-4V-Legierung TPMSS mit Hilfe der Röntgen-Computertomographie (XCT) durchgeführt. Es werden mehrere neue Bildanalyse-Workflows vorgestellt, um die Auswirkungen der Aufbaurichtung auf die Wanddickenverteilung, die Wanddegradation und die Verringerung der Oberflächenrauheit aufgrund des chemischen Ätzens von TPMSS zu bewerten. Es wird gezeigt, dass die Herstellungsgenauigkeit für die Strukturelemente, die parallel und orthogonal zu den hergestellten Schichten gedruckt werden, unterschiedlich ist. Verschiedene Strategien für das chemische Ätzen zeigten unterschiedliche Pulverabtragsfähigkeiten und damit ein Gradient der Wanddicke. Dies wirkte sich auf die mechanische Leistung unter Druck durch die Verringerung der Streckspannung aus. Eine positive Auswirkung des chemischen Ätzens ist die Verringerung der Oberflächenrauhigkeit, die möglicherweise die Ermüdungseigenschaften der Bauteile verbessern kann. Schließlich wurde XCT eingesetzt, um die Menge des zurückgehaltenen Pulvers mit der Porengröße des TPMSS zu korrelieren, wodurch der Herstellungsprozess weiter verbessert werden kann.
T2 - DGZfP-Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Additive Fertigung
KW - Computertomographie
KW - Wändedicke
KW - Machine Learning
PY - 2022
AN - OPUS4-55021
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pohl, P.
A1 - Kümmel, F.
A1 - Schunk, C.
A1 - Serrano-Munoz, Itziar
A1 - Markötter, Henning
A1 - Göken, M.
A1 - Höppel, H. W.
T1 - About the Role of Interfaces on the Fatigue Crack Propagation in Laminated Metallic Composites
N2 - The influence of gradients in hardness and elastic properties at interfaces of dissimilar materials in laminated metallic composites (LMCs) on fatigue crack propagation is investigated experimentally for three different LMC systems: Al/Al-LMCs with dissimilar yield stress and Al/Steel-LMCs as well as Al/Ti/Steel-LMCs with dissimilar yield stress and Young’s modulus, respectively. The damage tolerant fatigue behavior in Al/Al-LMCs with an alternating layer structure is enhanced significantly compared to constituent monolithic materials. The prevalent toughening mechanisms at the interfaces are identified by microscopical methods and synchrotron X-ray computed tomography. For the soft/hard transition, crack deflection mechanisms at the vicinity of the interface are observed, whereas crack bifurcation mechanisms can be seen for the hard/soft transition. The crack propagation in Al/Steel-LMCs was studied conducting in-situ scanning electron microscope (SEM) experiments in the respective low cycle fatigue (LCF) and high cycle fatigue (HCF) regimes of the laminate. The enhanced resistance against crack propagation in the LCF regime is attributed to the prevalent stress redistribution, crack deflection, and crack bridging mechanisms. The fatigue properties of different Al/Ti/Steel-LMC systems show the potential of LMCs in terms of an appropriate selection of constituents in combination with an optimized architecture. The results are also discussed under the aspect of tailored lightweight applications subjected to cyclic loading.
KW - Laminated metallic composites
KW - Toughening mechanisms
KW - Interfaces
KW - Fatigue crack propagation
KW - Fatigue crack growth
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526531
DO - https://doi.org/10.3390/ma14102564
VL - 14
IS - 10
SP - 2564
PB - MDPI
AN - OPUS4-52653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Van Tran, K.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Abou-Ras, D.
A1 - Puplampu, S.
A1 - Förster, C.
A1 - Penumadu, D.
A1 - Dahlberg, C. F. O.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography
N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale.
KW - Neutron tomography
KW - Phase distribution
KW - Rectangular cross-section
KW - Torsion
KW - Geometrical effect
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561649
DO - https://doi.org/10.1016/j.matdes.2022.111037
SN - 0264-1275
VL - 222
SP - 111037
PB - Elsevier Ltd.
AN - OPUS4-56164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tran, K. V.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Abou-Ras, D.
A1 - Puplampu, S.
A1 - Förster, C.
A1 - Penumadu, D.
A1 - Dahlberg, C. F. O.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography
N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale.
KW - Neutron tomography
KW - Phase distribution
KW - Rectangular cross-section
KW - Torsion
KW - Geometrical effect
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569101
DO - https://doi.org/10.1016/j.matdes.2022.111037
VL - 222
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-56910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pacheco, V.
A1 - Marattukalam, J. J.
A1 - Karlsson, D.
A1 - Dessieux, L.
A1 - Tran, K. V.
A1 - Beran, P.
A1 - Manke, I.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Sahlberg, M.
A1 - Woracek, R.
T1 - On the relationship between laser scan strategy, texture variations and hidden nucleation sites for failure in laser powder-bed fusion
N2 - While laser powder-bed fusion has overcome some of the design constraints of conventional manufacturing methods, it requires careful selection of process parameters and scan strategies to obtain favorable properties. Here we show that even simple scan strategies, complex ones being inevitable when printing intricate designs, can inadvertently produce local alterations of the microstructure and preferential grain orientation over small areas – which easily remain unnoticed across the macroscale. We describe how a combined usage of neutron imaging and electron backscatter diffraction can reveal these localized variations and explain their origin within cm-sized parts. We explain the observed contrast variations by linking the neutron images to simulated data, pole figures and EBSD, providing an invaluable reference for future studies and showing that presumably minor changes of the scan strategy can have detrimental effects on the mechanical properties. In-situ tensile tests reveal that fracture occurs in a region that was re-melted during the building process.
KW - Laser powder-bed fusion
KW - Texture
KW - Preferential orientation
KW - Diffraction contrast neutron imaging
KW - Bragg-edge
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568054
DO - https://doi.org/10.1016/j.mtla.2022.101614
VL - 26
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-56805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, T.
A1 - Kalinka, Gerhard
A1 - Mieller, Björn
T1 - Manufacturing and deformation behavior of alumina and zirconia helical springs at room temperature
N2 - Ceramic helical springs with identical dimensions were produced by hard machining from alumina, alumina toughened zirconia (ATZ), and tetragonal zirconia polycrystals (TZP) stabilized with different oxides. According to the results of the spring constant determination under deformation rates of 3 mm/min, the deformation behavior of all ceramic springs obeys to Hook’s law. However, variation of the deformation rate, tests under constant load, and spring recovery behavior revealed differences in the deformation behavior of alumina, TZP, and ATZ springs. Alumina springs exhibited time-independent deformation in all tests. In contrast, anelastic deformation at room temperature was demonstrated in all springs containing TZP. This deformation is completely reversible over a period of several days. Anelastic behavior is particularly pronounced in Y-TZP springs, whereas Ce-TZP springs exhibit comparatively very low but still reliably detectable anelasticity. Oxygen vacancies in the TZP ceramic are considered the most likely explanation for the anelastic behavior of TZP springs at room temperature.
KW - Alumina
KW - Creep
KW - Elastic properties
KW - Zirconia
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571858
DO - https://doi.org/10.1111/jace.19085
SN - 0002-7820
SP - 1
EP - 14
PB - Wiley-Blackwell
CY - Oxford [u.a.]
AN - OPUS4-57185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, Michela
A1 - Faglioni, Francesco
A1 - Chand, Keerthana
A1 - Hejazi, Bardia
A1 - Fioresi, Rita
A1 - Bruno, Giovanni
T1 - Chamfer distance for non-linear registration of Triply Periodic Minimal Surface lattices
N2 - We present a 3D image registration technique for non-linear deformation estimation in Additive Manufacturing processes. The methodology involves comparing X-ray Computed Tomography (XCT) data with Computer Aided Design (CAD) models for Triply Periodic Minimal Surface (TPMS) lattices and employs the Chamfer distance to refine mesh non-linear deformations.
KW - X-ray Computed tomography
KW - Defects
KW - Machine Learning
KW - Digital Twin
KW - Registration
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637367
DO - https://doi.org/10.1016/j.addlet.2025.100299
SN - 2772-3690
VL - 14
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rieder, Philipp
A1 - Petrich, Lukas
A1 - Serrano-Munoz, Itziar
A1 - Mouiya, Mossaab
A1 - Markötter, Henning
A1 - Huger, Marc
A1 - Bruno, Giovanni
A1 - Schmidt, Volker
T1 - Statistical analysis of grains and pores within polycrystalline Al2TiO5 ceramics, based on X-ray computed tomography
N2 - Advanced statistical image analysis workflows were developed to segment and quantitatively evaluate 2D electron-backscatter diffraction (EBSD) maps and 3D synchrotron X-ray computed tomography (SXCT) volumes of a polycrystalline Al2TiO5 refractory composite that contains microcracks and pores. Several size, shape, and further geometric descriptors were determined for both the solid phase (Al2TiO5 grains) and the pore space. The resulting pore-size distribution is distinctly bimodal: coarse pores (tens to hundreds of micrometers), traced to incomplete powder compaction, coexist with fine pores generated during sintering. The two pore populations appear to be correlated with grain growth and crystallographic orientation in different ways. Finally, the descriptors obtained from the 2D EBSD and 3D SXCT data sets are internally consistent but complementary, highlighting the value of characterizations based on EBSD and SXCT in the microstructural study of refractory ceramics.
KW - Synchrotron X-ray computed tomography
KW - Electron-backscatter diffraction
KW - Aluminum titanate
KW - Morphological reconstruction
KW - Image Segmentation
KW - Statistical image analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643918
DO - https://doi.org/10.1016/j.matchar.2025.115602
SN - 1044-5803
VL - 229
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-64391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruson, Danilo
A1 - Serrano-Munoz, Itziar
A1 - Fritsch, Tobias
A1 - Markötter, Henning
A1 - Galati, Manuela
T1 - Revealing the (positive) role of porosity within polymeric additively manufactured lattices via X-ray computed tomography
N2 - The mechanical properties of lattice geometries are known to be significantly influenced by a variety of manufacturing defects. This study investigates the influence of porosity on the mechanical behaviour of strut-based body-centred cubic (BCC) lattice structures produced with powder bed fusion with laser beam PBF-LB/P using PA2200 nylon powder. The study combines advanced techniques, including in-situ laboratory X-ray computed tomography (XCT), synchrotron XCT to visualise pores and roughness in high resolution at a single-cell level and image-based finite element analysis (FEA). The findings show that failure in thin-walled AM lattices is governed by the combined effects of porosity morphology, location, surface roughness, and cross-section reduction. The presence of internal porosity is found to attenuate both the amplitude of elastic modulus fluctuations and the severity of stress concentrations induced by surface irregularities.
KW - Nylon Pa2200
KW - Laser powder bed fusion (PBF-LB)
KW - Processing defects
KW - Synchrotron X-ray computed tomography (XCT)
KW - Digital volume correlation (DVC)
KW - Image-based finite element simulations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633245
DO - https://doi.org/10.1016/j.ijsolstr.2025.113488
SN - 0020-7683
VL - 320
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-63324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buljak, Vladimir
A1 - Serrano-Munoz, Itziar
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Prasek, Marko
A1 - Contillo, Adriano
A1 - Mouiya, Mossaab
A1 - Huger, Marc
A1 - Bruno, Giovanni
T1 - On the closure of thermally induced micro-cracks in aluminum titanate ceramics
N2 - Aluminum Titanate (AT) refractory ceramics (as some other ceramic composites) are prone to microcracking, due to the thermal expansion anisotropy of AT and to the mismatch with the thermal expansion of the constituents. Such microcracks cause the room temperature Young's modulus to be only a fraction of that of the non-microcracked material. As a function of temperature, the Young's modulus increases non-linearly. Such increase suggests that microcracks close or even heal at high temperatures. Upon cooling, thermal stress accumulates again, and microcracks re-open. This cycle is fully reversible. While confirming the hysteretic behavior of the Young's modulus, we observe that the amount of microcracks (as determined by in-situ Synchrotron X-ray refraction radiography) decreases linearly upon heating. The apparent mismatch between the Young's modulus and the microcrack content dependence on temperature is explained by a simple FEM model. Such model employs cohesive elements upon cooling, in order to estimate the amount of initial microcracks. On purpose, the model does not include healing upon heating and only allows crack closure. It predicts that crack closure continuously occurs upon heating, thereby qualitatively reproducing the nearly linear dependence of the X-ray refraction signal. It is therefore concluded that the sudden and non-linear increase of Young's modulus with temperature is mainly caused by crack healing. Such finding agrees with previous work and paves the road to a more systematic separation of crack closure and healing in flexible ceramics.
KW - X-ray computed tomography
KW - X-ray refraction radiography
KW - In-situ imaging
KW - BAMline
KW - Micromechanics
KW - BESSY II
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645082
DO - https://doi.org/10.1016/j.ceramint.2025.09.237
SN - 0272-8842
VL - 51
IS - 27
SP - 55141
EP - 55152
PB - Elsevier
CY - Amsterdam
AN - OPUS4-64508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
A1 - Lapenna, M.
A1 - Faglioni, F.
A1 - Fioresi, R.
T1 - Temperature-based pruning for input features in Graph Neural Networks
N2 - In the presentwork,we employ the concept of neural network temperature to prune unimportant features in input to aGraph Neural Network (GNN) architecture. In benchmark datasets for node and graph property prediction, each node comes equipped with a vector of numerous features. It is paramount to understand which information is actually necessary and which can be discarded, both for efficiency and explainability. The temperature is linked to the gradient activity due to the loss function minimization and leads to pruning of weight structures associated with small gradients. This study is done on different GNN architectures, one for node classification and another one for link prediction, and several benchmark datasets are employed.We compare the results with similar experiments previously conducted on the filters of Convolutional Neural Networks. Although still at the proof-of-concept stage, our temperature-based pruning technique stands as a promising alternative to state-of-the-art magnitude-based pruning techniques.
KW - Temperature-based pruning
KW - Graph Neural Networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640886
VL - 140
SP - 1
EP - 20
PB - Springer
AN - OPUS4-64088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gunnerek, R.
A1 - Soundarapandiyan, G.
A1 - Mishurova, T.
A1 - Schröder, J.
A1 - Bruno, Giovanni
A1 - Boykin, J.
A1 - Diaz, A.
A1 - Klement, U.
A1 - Hryha, E.ON
T1 - Chemical mechanical polishing of powder bed fusion – laser beam processed 316 L stainless steel
N2 - Additive manufacturing via powder bed fusion – laser beam (PBF-LB) enables the fabrication of complex geometries but suffers from inherently rough surfaces and surface tensile residual stresses, both of which can compromise structural integrity, particularly under fatigue loading. To address these limitations, this study investigates chemical mechanical polishing (CMP) as a surface finishing method for improving surface quality and modifying the residual stress state in PBF-LB 316 L stainless steel. The work uniquely examines how scan rotation (0◦ vs. 67◦ rotation) and contour parameters influence CMP effectiveness in material removal, surface smoothing, and subsurface stress redistribution. With a targeted material removal of 110 μm, CMP reduced surface roughness (Sa) by up to 94 %, achieving values as low as 0.7 μm. Microstructural analysis revealed no grain refinement but identified a thin, plastically deformed surface layer. This plastic deformation resulted in the transformation of tensile surface stresses (340 MPa) into beneficial compressive stresses ( 400 MPa), as confirmed by synchrotron X-ray diffraction, which also showed a shift toward isotropic strain distribution. Further, these findings demonstrate that the initial scan strategy influences CMP performance and that CMP can enhance both surface integrity and mechanical reliability without altering the underlying microstructure. This study advances the understanding of how process induced microstructure and surface features affect CMP outcomes, enabling more informed design of post-processing strategies for improved surface integrity and mechanical performance in additively manufactured metals.
KW - Residual stress
KW - Additive manufacturing
KW - Chemical mechanical polishing
KW - As-built microstructure
KW - Surface roughness
KW - Surface finishing
KW - Material removal
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640522
DO - https://doi.org/10.1016/j.jmatprotec.2025.119055
SN - 0924-0136/
VL - 345
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-64052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Hejazi, Bardia
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Bruno, Giovanni
T1 - D-CNN and VQ-VAE Autoencoders for Compression and Denoising of Industrial X-Ray Computed Tomography Images
N2 - The ever-growing volume of data in imaging sciences stemming from advancements in imaging technologies, necessitates efficient and reliable storage solutions for such large datasets. This study investigates the compression of industrial X-ray computed tomography (XCT) data using deep learning autoencoders and examines how these compression algorithms affect the quality of the recovered data. Two network architectures with different compression rates were used, a deep convolution neural network (D-CNN) and a vector quantized variational autoencoder (VQ-VAE). The XCT data used was from a sandstone sample with a complex internal pore network as a good test case for the importance of feature preservation. The quality of the decoded images obtained from the two different deep learning architectures with different compression rates were quantified and compared to the original input data. In addition, to improve image decoding quality metrics, we introduced a metric sensitive to edge preservation, which is crucial for three-dimensional data analysis. We showed that different architectures and compression rates are required depending on the specific characteristics needed to be preserved for later analysis. The findings presented here can aid scientists in determining the requirements and strategies needed for appropriate data storage and analysis.
T2 - 28th European Conference on Artificial Intelligence – Including 14th Conference on Prestigious Applications of Intelligent Systems (PAIS 2025)
CY - Bologna, Italy
DA - 25.10.2025
KW - Data Compression
KW - Deep Learning
KW - X-ray Computed Tomography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644758
UR - https://ebooks.iospress.nl/doi/10.3233/FAIA251480
DO - https://doi.org/10.3233/FAIA251480
SN - 0922-6389
SP - 1
EP - 8
PB - IOS Press
AN - OPUS4-64475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huber, Norbert
T1 - Machine learning in materials science and engineering – best practice, perspectives and pitfalls
N2 - Machine learning (ML) is increasingly utilized to support the data driven analysis of relationships in multidimensional parameter spaces, ideally as an entry point for a more general phenomenological or physics-based model development. Applications include both forward and inverse problems as well as forward problems, for example parameter identification or modeling of structure-property relationships.
The talk will give an overview over a variety of solutions that benefit from the capability of artificial neural networks to approximate and interpolate complex relationships that are represented by a set of sparse data. The reason behind is that numerical simulations as well as experiments do often not allow to generate enough data such that the data set is not sufficient for a deep-learning approach in connection with the complexity of the problem at hand.
After a short introduction to artificial neural networks along with recommendations for data generation and feature engineering, the talk will cover a range of examples from nanoindentation and material parameter identification, the improvement of characterization techniques by ML correction methods towards recent problems in the prediction of structure-property relationships for materials with complex microstructure. All these examples have in common that a successful ML model typically requires a comprehensive understanding of existing knowledge, expertise in translating this knowledge into meaningful input features, a compact ML architecture, and robust validation of the trained model. The talk will conclude with the example of nanoporous metals that demonstrates the importance of high-quality and bias-free data for the applicability and trustworthiness of the trained model, also emphasizing the need for a culture of open data, specifically towards curated data sets for training and validation of ML models.
T2 - WW-Colloquium Department of Materials Science and Engineering
CY - Nuremberg, Germany
DA - 13.01.2026
KW - Machine learning
KW - Nanoindentation
KW - Material testing
KW - Nanoporous metals
PY - 2026
AN - OPUS4-65358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
A1 - Fritsch, Tobias
A1 - Jahn, Anne
A1 - Pavasaryte, Lina
A1 - Bruno, Giovanni
T1 - Quantitative surface quality evaluation by X-ray Computed Tomography
N2 - The poor surface quality is one of the challenges in powder based additive manufacturing (AM) techniques. It limits the application of the components in as-manufactured condition and requires the post-processing machining techniques, increasing costs and diminishing the advantage of the free form fabrication. It is important to characterize the surface roughness of the part as it might affect the tolerances and the mechanical behavior of the material. For the AM components the usage of classic characterization techniques becomes very challenging and even impossible, when internal channels, fine and complex shapes structures are under investigation. In such cases, X-ray Computed Tomography (XCT) is the only tool to evaluate the structure inside nondestructively.
In this work, the application of surface quality analysis workflow using high-resolution XCT is presented. The analysis of surface topography includes the quantitative characterization of “re-entrant” surface features. This characterization is based on the evaluation of the triangulated surface generated based on the XCT data and was compared with conventional surface roughness parameters (e.g., Sa and Sz). The strength of the presented workflow is the application on arbitrary surfaces without geometrical limitations allowing real as-build investigation. This will be discussed on the example of both, simple cylindrical struts to present the principals, and the application to the Triply Periodic Minimal Surface (TPMS) structures. The analysis of the struts allows conclusions about the influence of down-skin and up-skin on surface quality. The results indicate that the surface quality is a factor of 2 worse for a build angle of 30° compared to an up-right build (90°). The investigation of TPMS structures is focused on the optimization of process parameter of geometrically complex samples regarding the surface quality. The challenge was an automated and user-independent comparison of several TPMS structures. The correlation of surface quality with process parameters (e.g., Laser power, laser velocity) is presented.
T2 - ASTM ICAM 2024
CY - Atlanta, GA, USA
DA - 28.10.2024
KW - Additive manufacturing
KW - X-ray CT
KW - Surface texture
PY - 2024
AN - OPUS4-61515
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eddah, Mustapha
T1 - Synchrotron Multi-energy HDR tomography for LTCC systems
N2 - LTCCs (Low-temperature co-fired ceramics) consist of three-dimensionally distributed, hermetically bonded ceramic and metallic components with structure sizes within [10; 100] µm. A non-destructive imaging technique is needed that provides 3D, sharp, high-contrast resolution of these structures, as well as porosity and defect analysis, which is made difficult by the very different X-ray absorption coefficients of the individual components of the microstructure. A HDR method is being developed that allows a combination of different tomograms, each with X-ray energies adapted to individual materials.
T2 - Bessy II User Meeting
CY - Berlin, Germany
DA - 22.06.2023
KW - LTCC
KW - Synchrotron tomography
KW - Data fusion
KW - In-situ tomography
PY - 2023
AN - OPUS4-57795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Mishurova, Tatiana
T1 - Influence of residual stress and microstructure on mechanical performance of LPBF TI-6AL-4V
N2 - Additive manufacturing technologies provide unique possibilities in the production of topologically optimized, near-net shape components. The main limiting factors affecting the structural integrity of Laser Powder Bed Fusion (LPBF) parts are manufacturing defects and residual stress (RS) because both of them are virtually inevitable. Taking into account the complex thermal history of LPBF materials, a prediction of the material behavior is not possible without experimental data on the microstructure, defect distribution, and RS fields. Therefore, this thesis aims to understand the factors that influence the LPBF Ti-6Al-4V material performance the most, covering both the production and the post-processing steps of manufacturing.
Indeed, a parametric study on the influence of manufacturing process and post-processing on RS, defects and microstructure was performed. It was found that the volumetric energy Density (EV), commonly used for the LPBF process optimization, does neither consider the pore shapes and distribution, nor the influence of individual parameters on the volume fraction of pores.
Therefore, it was recommended not to use EV without great care. It was shown that the Position on the base plate has a great impact on the amount of RS in the part.
The micromechanical behavior of LPBF Ti-6Al-4V was also studied using in-situ Synchrotron X-ray diffraction during tensile and compression tests. Diffraction elastic constants (DEC), connecting macroscopic stress and (micro) strain, of the LPBF Ti-6Al-4V showed a difference
from the DEC of conventionally manufactured alloy. This fact was attributed to the peculiar microstructure and crystallographic texture. It was therefore recommended to determine experimentally DECs whenever possible.
Low Cycle Fatigue (LCF) tests at a chosen operating temperature were performed to evaluate the effect of post-treatment on the mechanical performance. Through the information on the microstructure, the mesostructure, and the RS, the LCF behavior was (indirectly) correlated to the process parameters. It was found that the fatigue performance of LPBF samples subjected to hot isostatic pressing is similar to that of hot-formed Ti-6Al-4V. The tensile RS found at the
surface of LPBF as-built samples decreased the fatigue life compared to the heat-treated samples. The modification of the microstructure (by heat treatment) did not affect the Fatigue performance in the elastic regime. This shows that in the absence of tensile RS, the manufacturing defects solely control the failure of LPBF components and densification has the strongest effect on the improvement of the mechanical performance.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Residual stress
KW - Computed tomography
PY - 2021
SP - 1
EP - 143
CY - RWTH Aachen
AN - OPUS4-54389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Texturing of calcium cobaltite for thermoelectric applications by pressure assisted sintering
N2 - Thermoelectric materials can convert waste heat directly into electrical power by using the Seebeck effect. Calcium cobaltite (CCO) is considered as a promising thermoelectric p-type oxide for energy harvesting applications at temperatures above 500 °C. The properties and morphology of single-crystal CCO are strongly anisotropic because of its crystal structure of alternating layers of CoO2 and Ca2CoO3. By aligning the plate-like grains, the anisotropic properties of the grains can be assigned to the poly-crystalline parts.
In this study, the combination of tape casting and pressure-assisted sintering is used to texture and densify large scale components (50 cm²). Thereby, the influence of powder preparation and applied pressure during sintering on texturing and thermoelectric properties is investigated.
The analysis of XRD pole figures revealed that tape casting already leads to highly textured CCO. By pressure variation during sintering, the microstructure of CCO can be tailored either toward maximum power factor as required for energy harvesting or toward maximum figure of merit as required for energy recovery. Low pressure lead to a porous microstructure and maximum figure of merit and higher pressure to full densification and maximum power factor. The electrical and thermal conductivity of CCO seem depending on both texture and sinter density.
T2 - KERAMIK 2021 / CERAMICS 2021
CY - Online meeting
DA - 19.04.2021
KW - Thermoelectrics
KW - Hot pressing
KW - Pole figures
PY - 2021
AN - OPUS4-52490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Bruno, Giovanni
ED - Makul, Matt
T1 - Investigation of a New Ti Alloy for a New Generation of Additively Manufactured Implants with Lattice
N2 - A new titanium alloy improving the operation of implants additively manufactured and including laterally closed lattice structures is proposed. The new alloy possesses an increased affinity to the bone. The measured bone–interface implant (BII) of less than 10 mm and bone–implant contact (BIC) of 95% demonstrated an excellent osseointegration. Furthermore, since additive manufacturing naturally leads to a high-roughness surface finish, the wettability of the implant is increased. The combination of these factors is pushing ossification beyond its natural limits. In addition, the quality and speed of the ossification and osseointegration in/around laterally closed lattice implants open the possibility of bone spline key of prostheses. This enables the stabilization of the implant into the bone while keeping the possibility of punctual hooks allowing the implant to be removed more easily if required.
KW - X-ray Computed tomography
KW - Defects
KW - Machine Learning
KW - Implants
KW - Lattices
PY - 2024
DO - https://doi.org/10.9734/bpi/cpstr/v7/7198E
VL - 7
SP - 12
EP - 37
AN - OPUS4-59754
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Residual Stresses in Additive Manufacturing (L-PBF)
N2 - Metal Additive manufacturing (AM) technologies such as Laser Powder Bed Fusion (LPBF) enable the fabrication of complex structures, giving rise to potential improvements in component and manufacturing efficiency. However, the processes are typically characterized by the generation of high magnitude residual stress (RS) which can have detrimental consequences for subsequent applications. Therefore, the characterization of these RS fields and the understanding of their formation and mitigation through optimized processing is crucial for the wider uptake of the technology. Due to the potential complex nature and high value of components manufactured by LPBF, it is important to have suitable characterisation methods which can determine the spatial variations of RS in a non-destructive manner. Neutron diffraction is considered to be the best suited for these requirements. However, the microstructures developed in the complex thermal cycles experience in the production can pose challenges to the ND method for RS analysis. The BAM has conducted significant research over the past years to overcome these obstacles, enabling higher confidence in the RS determined in LPBF materials by neutron diffraction. This contribution will overview some of these advancements made recently at European neutron sources including on Stress-Spec at FRM2/MLZ.
T2 - MLZ User Meeting 2021
CY - Online meeting
DA - 07.12.2021
KW - Residual stress
KW - Additive manufacturing
KW - Diffraction
KW - AGIL
KW - Manufact
PY - 2021
AN - OPUS4-54044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Thermoelectric multilayer generators: development from oxide powder to demonstrator
N2 - Thermoelectric generators can be used for energy harvesting by directly transforming a temperature gradient into a voltage. Multilayer generators based on ceramic multilayer technology are an interesting alternative to conventional π-type generators. They exhibit several advantages like high filling factor, possibility of texturing, co-firing of all materials in one single-step, and reduction of production costs due to the high possible degree of automation. But, co-firing of promising oxide thermoelectric materials, Ca3Co4O9 (p-type) and CaMnO3 (n-type), is very challenging due to the large difference in sintering temperature (300 K).
In this work we show the material development of Ca3Co4O9, CaMnO3, and insulation for multilayer generators co-fired under uniaxial pressure at 900 °C. The materials are tailored regarding their sintering behavior, electrical performance and coefficients of thermal expansion. Tape-casting and pressure assisted sintering are applied to fabricate textured Ca3Co4O9. Compared to conventional sintering, pressure assisted sintering increases the strength by the factor 10 and the power factor by the factor of 20. The combination of sintering additives and uniaxial pressure is used to decrease the sintering temperature of CaMnO3 to 900 °C while maintaining acceptable thermoelectric properties.
Different generator designs (unileg and pn-type) were fabricated and analyzed regarding microstructure and thermoelectric performance. A lower level of complexity is beneficial for co-firing and performance. The unileg demonstrators reach 80% of the simulated output power and the power output is highly reproducible between the different demonstrators (99%).
T2 - Ceramics in Europe 2022
CY - Krakow, Poland
DA - 10.07.2022
KW - Thermoelectrics
KW - Multilayer technology
KW - Co-firing
KW - Texture
PY - 2022
AN - OPUS4-55357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Influence of the scanning strategy on the RS state of a LPBF IN718 material
N2 - For metal-based additive manufacturing (AM) to achieve leaner designs and enable longer life predictions, it is imperative to gain a detailed knowledge of the residual stress (RS) built-up. Laser powder bed fusion (LPBF) is an AM technique particularly prone to RS because of the highly localized heat source, extremely high cooling rates (in the order of 103-107 K/s), and successive cooling and heating cycles of the solidified material. Furthermore, RS analysis of LPBF materials by diffraction methods is peculiar because of the complexity of the thermal history, the possibility of encountering high levels of surface roughness, spatial textural variations and/or changes in solute concentrations at the component scale.
Diverse aspects of the influence of scanning strategies on the as-built residual stress state of a LPBF IN718 alloy will be presented, with particular focus on the challenges that AM microstructures pose for a reliable RS determination.
T2 - MECASENS 2021
CY - Prague, Czech Republic
DA - 25.11.2021
KW - Laser Powder Bed Fusion
KW - IN718
KW - Residual stress analysis
PY - 2021
AN - OPUS4-53875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hejazi, Bardia
A1 - Compart, Amaya
A1 - Fritsch, Tobias
A1 - Wagner, Ruben
A1 - Weidner, Anja
A1 - Biermann, Horst
A1 - Benz, Christopher
A1 - Sander, Manuela
A1 - Bruno, Giovanni
T1 - Fatigue Crack Segmentation and Characterization of Additively Manufactured Ti‐6Al‐4V Using X‐Ray Computed Tomography
N2 - X‐ray computed tomography (XCT) is extremely useful for the non‐destructive analysis of additively manufactured (AM) components. AM components often show manufacturing defects such as lack‐of‐fusion (LoF), which are detrimental to the fatigue life of components. To better understand how cracks initiate and propagate from internal defects, we fabricated Ti‐6Al‐4V samples with an internal cavity using electron beam powder bed fusion. The samples were tested in high‐cycle and very high‐cycle fatigue regimes. XCT was used to locate crack initiation sites and to determine characteristic properties of cracks and defects with the aid of deep learning segmentation. LoF defects exposed to the outer surface of the samples after machining were found to be as detrimental to fatigue life as the internal artificial defects. This work can benefit industries that utilize the AM of high‐strength, lightweight alloys, in the design and manufacturing of components to improve part reliability and fatigue life.
KW - Additive manufacturing
KW - Deep learning
KW - Ttitanium alloy
KW - Very high-cycle fatigue
KW - X-ray computed tomography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615107
DO - https://doi.org/10.1111/ffe.14489
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-61510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voloskov, Boris
A1 - Mishurova, Tatiana
A1 - Evlashin, Stanislav
A1 - Firsov, Denis
A1 - Bruno, Giovanni
A1 - Sergeichev, Ivan
T1 - Influence of scanning strategy and hatch distance on porosity and mechanical characteristics of 316L stainless steel produced by laser powder bed fusion
N2 - The effect of scanning strategies and hatch distances on the porosity and mechanical properties of 316L stainless steel produced by laser powder bed fusion (PBF-LB) is studied. Two scanning strategies were analyzed along with three hatch distances (50 μm, 80 μm, and 110 μm). Using X-ray computed tomography (XCT), the study revealed different defect distributions: 90° alternating hatch scanning strategy resulted in a higher number of lack of fusion defects, while the chessboard strategy produced smaller, more uniformly distributed gas pores. The optimal hatch distance of 80 μm was found to minimize porosity and maximize tensile strength for both strategies. Mechanical testing supported these findings, showing that specimens printed with an 80 μm hatch distance exhibited better mechanical characteristics. This study highlights the critical role of scanning parameters in the quality
and reliability of additively manufactured parts.
KW - X-ray computed tomography
KW - Additive manufacturing
KW - Porosity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621164
DO - https://doi.org/10.1016/j.prostr.2024.11.045
SN - 2452-3216
VL - 65
SP - 302
EP - 309
PB - Elsevier B.V.
AN - OPUS4-62116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Heldmann, A.
A1 - Hofmann, M.
A1 - Evans, Alexander
A1 - Petry, W.
A1 - Bruno, Giovanni
T1 - Determination of diffraction and single-crystal elastic constants of laser powder bed fused Inconel 718
N2 - High energy X-ray synchrotron diffraction is used to investigate the elastic anisotropy of the nickel-based superalloy IN718 produced by laser powder bed fusion (PBF-LB). This material is characterized by a columnar grain morphology with some crystallographic texture. The material is subjected to elastic loading to determine the diffraction elastic constants (DECs). Furthermore, the single-crystal elastic constants (SCEC) are refined from these experiments using different micromechanical models. The results show that each micromechanical model predicts a specific set of SCEC that well describes the elastic anisotropy of PBF-LB/IN718.
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - Condensed Matter Physics
KW - General Materials Science
PY - 2023
DO - https://doi.org/10.1016/j.matlet.2023.135305
SN - 0167-577X
VL - 353
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-58477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - High temperature in-situ heat treatment of a refractory material by means of synchrotron refraction radiography
N2 - The stress–strain behavior of certain ceramics, such as aluminum titanate (AT, Al2TiO5), has features that are unusual for brittle material. In particular, a substantial nonlinearity under uniaxial tension, and load–unload hysteresis caused by the increase of the incremental stiffness at the beginning of unloading. These features are observed experimentally and attributed to microcracking. In this study, we investigate the mechanical response of an AT material at room and high temperature. Microstructure and microcracking are analyzed by means of electron microscopy, and both synchrotron micro computed tomography (µCT) and refraction radiography (SXRR). Synchrotron refraction radiography is combined with in-situ heating at high-temperatures (up to 1400°C) to be able to monitor the relative closure of microcracks as a function of increasing/decreasing temperatures.
T2 - 21st European Conference on Composite Materials (ECCM21)
CY - Nantes, France
DA - 02.07.2024
KW - Refractory materials
KW - Microcracking
KW - Synchrotron µCT and refraction radiography
KW - In-situ heating up to 1400°C
PY - 2024
AN - OPUS4-60576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Laquai, René
T1 - Extending synchrotron X-ray refraction imaging techniques to the quantitative analysis of metallic materials
N2 - In this work, two X-ray refraction based imaging methods, namely, synchrotron X-ray refraction radiography (SXRR) and synchrotron X-ray refraction computed tomography (SXRCT), are applied to analyze quantitatively cracks and porosity in metallic materials.
SXRR and SXRCT make use of the refraction of X-rays at inner surfaces of the material, e.g., the surfaces of cracks and pores, for image contrast. Both methods are, therefore, sensitive to smaller defects than their absorption based counterparts X-ray radiography and computed tomography. They can detect defects of nanometric size.
So far the methods have been applied to the analysis of ceramic materials and fiber reinforced plastics. The analysis of metallic materials requires higher photon energies to achieve sufficient X-ray transmission due to their higher density. This causes smaller refraction angles and, thus, lower image contrast because the refraction index depends on the photon energy. Here, for the first time, a conclusive study is presented exploring the possibility to apply SXRR and SXRCT to metallic materials. It is shown that both methods can be optimized to overcome the reduced contrast due to smaller refraction angles. Hence, the only remaining limitation is the achievable X-ray Transmission which is common to all X-ray imaging methods. Further, a model for the quantitative analysis of the inner surfaces is presented and verified.
For this purpose four case studies are conducted each posing a specific challenge to the imaging task. Case study A investigates cracks in a coupon taken from an aluminum weld seam. This case study primarily serves to verify the model for quantitative analysis and prove the sensitivity to sub-resolution features. In case study B, the
damage evolution in an aluminum-based particle reinforced metal-matrix composite is analyzed. Here, the accuracy and repeatability of subsequent SXRR measurements is investigated showing that measurement errors of less than 3% can be achieved. Further, case study B marks the fist application of SXRR in combination with in-situ tensile loading. Case study C is out of the highly topical field of additive manufacturing. Here, porosity in additively manufactured Ti-Al6-V4 is analyzed with a special interest in the pore morphology. A classification scheme based on SXRR measurements is devised which allows to distinguish binding defects from keyhole pores even if the defects cannot be spatially resolved. In case study D, SXRCT is applied to the analysis of hydrogen assisted cracking in steel. Due to the high X-ray attenuation of steel a comparatively high photonenergy of 50 keV is required here. This causes increased noise and lower contrast in the data compared to the other case studies. However, despite the lower data quality a quantitative analysis of the occurance of cracks in dependence of hydrogen content and applied mechanical load is possible.
N2 - In der vorliegenden Arbeit werden die zwei, auf Refraktion basierende, Röntgenbildgebungsverfahren Synchrotron Röntgen-Refraktions Radiographie (engl.: SXRR) und Synchrotron Röntgen-Refraktions Computertomographie (engl.: SXRCT) für die quantitative Analyse von Rissen und Porosität in metallischenWerkstoffen angewandt. SXRR und SXRCT nutzen die Refraktion von Röntgenstrahlen an inneren Oberflächen des Materials, z.B. die Oberflächen von Rissen und Poren, zur Bildgebung. Beide Methoden sind daher empfindlich gegenüber kleineren Defekten als ihre auf Röntgenabsorption basierenden Gegenstücke, Röntgenradiographie und Röntgen-Computertomographie.
Sie sind in der Lage Defekte von nanometrischer Größe zu detektieren. Bislang wurden die Methoden für die Analyse von keramischen Werkstoffen und faserverstärkten Kunststoffen eingesetzt. Die Analyse von metallischenWerkstoffen benötigt höhere Photonenenergien benötigt werden um eine ausreichende Transmission zu erreichen.
Dies hat kleinere Refraktionswinkel, und damit geringeren Bildkontrast, zur Folge, da der Brechungsindex von der Photonenenergie abhängt. Hier wird erstmals eine umfassende Studie vorgelegt, welche die Möglichkeiten zur Untersuchung metallischer Werkstoffe mittels SXRR und SXRCT untersucht. Es wird gezeigt, dass der geringere Kontrast, verursacht durch die kleineren Refraktionswinkel, überwunden werden kann. Somit ist die einzig verbleibende Beschränkung die erreichbare Transmission, die alle Röntgenbildgebungsverfahren gemeinsam haben. Darüber hinaus wird ein Modell für die quantitative Auswertung der inneren Oberflächen präsentiert und verifiziert.
Zu diesem Zweck werden vier Fallstudien durchgeführt, wobei jede eine spezifische Herausforderung darstellt. In Fallstudie A werden Risse in einer Probe aus einer Aluminiumschweißnaht untersucht. Diese Fallstudie dient hauptsächlich dazu das Modell für die quantitative Analyse zu verifizieren und die Empfindlichkeit gegenüber Strukturen unterhalb des Auflösungsvermögens zu beweisen. In Fallstudie B wird die Entwicklung der Schädigung in einem aluminiumbasierten partikelverstärktem Metall-Matrix Komposit untersucht. Dabei wird die Genauigkeit und Wiederholbarkeit der SXRR Messungen analysiert und es wird gezeigt das Messfehler kleiner 3% erreicht werden können. Darüber hinaus wird in Fallstudie B erstmals SXRR in Kombination mit in-situ Zugbelastung eingesetzt. Fallstudie C ist aus dem hochaktuellen Bereich der additive Fertigung. Hier wird Porosität in additiv gefertigtem Ti-Al6-V4 analysiert mit besonderem Augenmerk auf der Morphologie der Poren. Es wurde ein Verfahren zur Klassifizierung, basierend auf SXRR Messungen, erfunden, welches Bindefehler und Poren voneinander unterscheiden kann auch wenn die Defekte nicht räumlich aufgelöst werden können. In Fallstudie D wird SXRCT zur Analyse von wasserstoffunterstützter Rissbildung in Stahl angewandt. Wegen der hohen Röntgenschwächung des Stahls muss hier mit 50 keV eine vergleichsweise hohe Photonenenergie genutzt werden.
Dadurch zeigen die Daten ein erhöhtes Rauschen und geringeren Kontrast verglichen mit den anderen Fallstudien. Allerdings ist es, trotz der geringeren Datenqualität, möglich das Auftreten von Rissen in Abhängigkeit der Wasserstoffkonzentration und mechanischen Belastung zu untersuchen.
KW - Synchrotron X-ray refraction computed tomography
KW - Lean duplex steel X2CrMnNiN21-5-1
KW - hydrogen embrittlement
KW - Metal-matrix composite
KW - Al6061
KW - Ti-Al6-V4
KW - In-situ tensile test
PY - 2022
SP - 1
EP - 71
AN - OPUS4-54385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Skalenübergreifende Materialcharakterisierung basierend auf Computertomographiedaten
N2 - Die BAM präsentiert anhand ausgewählter Beispiele wie mithilfe von Computertomographiedaten dringende technische Fragestellungen zum Verständnis von Schädigungsmechanismen in verschiedensten Materialien und Komponenten, zum Beispiel in additiv gefertigten Metallen oder Batterien, beantwortet werden können.
T2 - VisiConsult Röntgen-Technologietag 2024 -- Transformation in der ZfP
CY - Stockelsdorf, Germany
DA - 10.10.2024
KW - Computertomographie
KW - Batterie
KW - Additive Fertigung
KW - Synchrotron
KW - BAMline
PY - 2024
AN - OPUS4-61431
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - Towards the optimization of post laser powder bed fusion stress relieve treatments of stainless steel 316L
N2 - The laser powder bed fusion of 316L leads to the formation of large residual stress. In this presentation, different stress relieve treatments were employed to assess their potential to relax the residual stress. The residual stress was determined by X-ray and neutron diffraction. The results give insights on the range of relaxation one can obtain by employing low and high temperature heat treatments and relates the relaxation to changes in the microstructure.
T2 - Online-Sitzung des Fachausschusses 13 - Eigenspannungen
CY - Online meeting
DA - 08.12.2021
KW - AGIL
KW - Residual Stress
KW - X-ray and Neutron Diffraction
KW - Additive Manufacturing
KW - Stainless Steel
PY - 2021
AN - OPUS4-53947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Thin-film capability of commercial LTCC
N2 - Low-temperature co-fired ceramics (LTCC) are used to fabricate multilayer circuits which are robust in harsh environments. Thick-film technology is well established for the metallization of circuit boards and microsystems. For specific sensor applications, the combination of LTCC and thin-film technology is advantageous to reach higher structure resolutions. Due to the high roughness of as-fired LTCC surfaces compared with silicon-wafers, the deposition of low-defect- films with narrowly specified properties is challenging. The deposited thin-films are structured either by lift-off or by etching. The latter is less error-prone and thus preferred in industry provided the selected materials allow it. There is spare literature about thin films on commercial LTCC comparing different material systems or sintering techniques. For developing thin-film sensors on multilayer circuits it is crucial to identify thin-film-compatible commercial LTCC material as well as the crucial surface properties. In this work we evaluate the thin-film capability of different LTCC compositions and surface qualities.
To evaluate the influence of the material composition on the thin film capability, 200 nm Ni-thin films were deposited on three different constrained-sintered LTCC (CT708, CT800 and DP951) by electron beam physical vapour deposition. The effect of surface quality was assessed by thin-film deposition on free-sintered, pressure-assisted sintered, and polished DP951. The thin-films were structured by covering corresponding sections with a UV-curable photo resin and subsequent etching of the uncovered surface, leaving behind the desired structure.
The etched Ni-thin films showed high difference in failure rate and sheet resistance regarding the used LTCC-material. DP951 had the lowest sheet resistance and no failure, whereas CT800 had a high sheet resistance and a failure rate of 40 %. These results are correlated with surface roughness of the LTCC, scanning electron micrographs of the deposited thin-films, and the chemical resistance of the LTCC against commonly used etching media. Contrary to the expectations, no correlation between roughness and thin-film capability was found. The LTCC with high failure rate showed a strong chemical attack by the used etching medium. Additionally, the adhesion of thin-films on DP951 is better than on CT708 and CT800.
T2 - XVIII EcerS Conference & Exhibition
CY - Lyon, France
DA - 02.07.2023
KW - Glass-ceramics
KW - Etching
KW - Resistance
PY - 2023
AN - OPUS4-58019
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Papaioannou, Savvina Maria
T1 - XCT image analysis for characterizing 3D printed thermomagnetic materials in energy harvesting applications
N2 - A critical amount of industrial energy input is lost as waste heat, and this amount peaks just above room temperature. The aim of this work is to develop a technology to convert this low-grade waste heat into electricity through a thermomagnetic generator based on Faraday's law of induction. To this end, water-flowable thermomagnetic elements are developed by the industrial partner to be used as heat exchanger components in the demonstrator. The 3D extrusion and post heat treatment process of the developed fine parts may introduce various defects that have an impact on their heat transfer efficiency, magnetic and mechanical properties.
Here, the non-destructive characterisation technique of X-ray computed tomography (XCT) is used to evaluate the morphology of the developed components and to identify trends that contribute to the improvement of material performance in the demonstrator. In specific, XCT image analysis enables the 3D visualisation of the developed 3D-printed structures. Using DragonFly software, scalar quantities such as volume, total surface area and void fraction are estimated for each sample. More specifically, image segmentation using Otsu’s thresholding method, combined with morphological operations on the reconstructed 3D XCT volume, contributes to the estimation of the mean filament diameter, mean channel width and distribution of internal porosity along the printing direction. In addition, the repeatability and dimensional accuracy of the printing process are evaluated through slice analysis of each 3D-printed block, both along and perpendicular to the water-flow direction.
T2 - Delft Days on Magnetocalorics (DDMC)
CY - Delft, Netherlands
DA - 20.11.2025
KW - X-ray computed tomography
KW - Image analysis
KW - Thermomagnetic
KW - Heat exchangers
PY - 2025
AN - OPUS4-65249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Bestimmung der elektrischen Durchschlagfestigkeit keramischer Werkstoffe - Einfluss von Messverfahren und -umgebung
N2 - Als elektrische Durchschlagfestigkeit bezeichnet man die elektrische Feldstärke, bei der es zur Entladung durch ein isolierendes Medium kommt. Im Falle von Festkörpern ist dies ein zerstörender Prozess. Bei der messtechnischen Bestimmung der Durchschlagfestigkeit haben neben den verwendeten Messgeräten auch die eingesetzten Elektroden, die Form des Prüfkörpers und das Isoliermedium, in dem die Prüfung stattfindet, einen signifikanten Einfluss auf die ermittelten Messwerte. Im Vortrag werden die Einflüsse erläutert und anhand von Messreihen aus der Literatur und der eigenen Forschung quantifiziert. Aufgrund der vorgestellten Effekte wird klar, dass es sich bei elektrischer Durchschlagfestigkeit nicht um absolute Materialkennwerte handelt, sondern vielmehr um systemabhängige Größen.
T2 - 7. Sitzung des Fachausschusses 6 - Material- und Prozessdiagnostik der Deutschen Keramischen Gesellschaft (DKG)
CY - Online meeting
DA - 16.02.2023
KW - Keramik
KW - Hochspannungsprüfung
KW - Durchschlagfestigkeit
PY - 2023
AN - OPUS4-57015
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Synchrotron X-Ray Refraction detects microstructure and porosity evolution during in-situ heat treatments
N2 - The complexity of any microstructural characterization significantly increases when there is a need to evaluate the microstructural evolution as a function of temperature. To date, this characterization is primarily performed by undertaking elaborative ex-situ experiments where the material’s heating procedure is interrupted at different temperatures or times. Moreover, these studies are often limited to a region smaller than the representative elementary volume, which can lead to partial or even biased interpretations of the collected data. This limitation can be greatly overcome by using in-situ synchrotron X-ray refraction (SXRR). In this study, SXRR has been combined with in-situ heat treatment to monitor the porosity evolution as a function of temperature. This technique is a robust and straightforward method for time-resolved (3-5 min required per scan) evaluation of thermally induced microstructural changes over macroscopically relevant volumes.
T2 - AAM2022, Alloys for Additive Manufacturing Symposium
CY - Munich, Germany
DA - 12.09.2022
KW - Synchrotron X-Ray Refraction
KW - In situ heating
KW - AlSi10Mg
KW - Laser powder bed fusion
KW - Thermally induced porosity
PY - 2022
AN - OPUS4-55779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wieder, Frank
T1 - X-ray refraction radiography applied to Dental Fibre Posts
N2 - Fibre-Matrix-Debonding in glass fibre reinforced dental posts can play an important role for their mechanical performance and long term stability… We show that synchrotron X-ray refraction radiography (SXRR) allows analysis of large samples (up to several millimetres) without compromising the detectability of sub micrometer defects.
T2 - HZB User Meeting 2021
CY - Online meeting
DA - 09.12.2021
KW - X-ray refraction
KW - Fiber reinforced dental post
KW - Fiberglass composite
KW - Non-destructive testing
PY - 2021
AN - OPUS4-54092
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Synchrotron X-Ray Refraction during in-situ heat treatments
N2 - For the first time, synchrotron X-ray refraction radiography (SXRR) has been paired with in-situ heat treatment to monitor microstructure and porosity evolution as a function of temperature.
T2 - HZB User Meeting 2021
CY - Online meeting
DA - 09.12.2021
KW - Synchrotron refraction radiography
KW - Laser powder bed fusion
KW - AlSi10Mg alloy
KW - In-situ heat treatment
KW - Porosity growth
PY - 2021
AN - OPUS4-53973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belli, R.
A1 - Hurle, K.
A1 - Schürrlein, J.
A1 - Petschelt, A.
A1 - Werbach, K.
A1 - Peterlik, H.
A1 - Rabe, Torsten
A1 - Mieller, Björn
A1 - Lohbauer, U.
T1 - Relationships between fracture toughness, Y2O3 fraction and phase content in modern dental Yttria-doped zirconias
N2 - The relationship between fracture toughness and Yttria content in modern zirconia ceramics was revised. For that purpose, we evaluated here 10 modern Y2O3-stabilized zirconia (YSZ) materials currently used in biomedical applications, namely prosthetic and implant dentistry. The most relevant range between 2-5 mol% Y2O3 was addressed by selecting from conventional opaque 3 mol% YSZ up to more translucent compositions (4-5 mol% YSZs). A technical 2YSZ was used to extend the range of our evaluation. The bulk mol% Y2O3 concentration was measured by X-Ray Fluorescence Spectroscopy. Phase quantification by Rietveld refinement considered two tetragonal phases or an additional cubic phase. A first-account of the fracture toughness (KIc) of the pre-sintered blocks is given, which amounted to 0.4 – 0.7 MPa√m. In the fully-densified state, an inverse power-law behavior was obtained between KIc and bulk mol% Y2O3 content, whether using only our measurements or including literature data, challenging some established relationships. A linear relationship between KIc and the fraction of the transformable t-phase was established within the range of 30–70 vol%.
KW - Ceramics
KW - Dental
KW - Zirconia
KW - Fracture toughness
KW - X-ray-diffraction
KW - Power law
PY - 2021
DO - https://doi.org/10.1016/j.jeurceramsoc.2021.08.003
VL - 41
IS - 15
SP - 7771
EP - 7782
PB - Elsevier Ltd.
AN - OPUS4-53107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D.
A1 - Paveleva, A.
A1 - Kozadayeva, M.
A1 - Evsevleev, Sergei
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
A1 - Surmenev, R.
A1 - Koptyug, A.
A1 - Surmeneva, M.
T1 - Trapped powder removal from sheet-based porous structures based on triply periodic minimal surfaces fabricated by electron beam powder bed fusion
N2 - Electron Beam Powder Bed Fusion-manufactured (E-PBF) porous components with narrow pores or channels and rough walls or struts can be filled with trapped powder after the manufacturing process. Adequate powder removal procedures are required, especially for high-density porous structures. In the present research, sheetbased porous structures with different thicknesses based on triply periodic minimal surfaces fabricated by EPBF were subjected to different post-processing methods, including a traditional powder recovery system for EPBF, chemical etching and ultrasound vibration-assisted powder removal. Wall thickness, internal defects, microstructure and morphology features, powder distribution inside the specimens, mechanical properties and deformation modes were investigated. A powder recovery system could not remove all residual powder from dense structures. In turn, chemical etching was effective for surface morphology changes and subsurface layers elimination but not for powder removal, as it affected the wall thickness, considerably influencing the mechanical properties of the whole structure. The ultrasound vibration method was quite effective for the removal of residual powder from sheet-based TMPS structures and without a severe degradation of mechanical properties. 10.1016/j.msea.2022.144479 Ultrasound vibration also caused grain refinement.
KW - Additive manufacturing
KW - Residual powder removal
KW - Ti6Al4V alloy
KW - Electron beam powder bed fusion
KW - TPMS structures
PY - 2023
DO - https://doi.org/10.1016/j.msea.2022.144479
VL - 862
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-56564
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kang, M.
T1 - Influence of mica particle content in composites for high voltage applications produced by additive manufacturing and mold casting
N2 - The insulation system of high voltage electrical devices like generators and electrical motors has to withstand thermal, electrical, ambient and mechanical influences (TEAM) during operation. Especially the dielectric properties have to satisfy the requirements also under elevated temperatures and extreme environments. To provide this high quality, the conventional fabrication process uses partly manually applied insulation tapes combined with a cost-intensive and under safety concerns at least problematic vacuum pressure impregnation step (VPI). In order to reduce process costs by increasing the degree of automation and avoiding the VPI process, additively manufactured (AM) insulations were studied. This study focuses on the fabrication of ceramic/polymer compounds via AM technique. The AM technology used a rotating screw extrusion print head with air pressure to supply the paste. Plate-like samples with dimensions of 55 mm x 55 mm x1mm thickness were produced. This work focuses on the homogeneously high viscous paste with 12.5 to 50 volume % ratio of filler particles. Three types of mica powders as ceramic filler materials with different particle sizes from micro to mm scale were evaluated. The controlled volume % ratio of particles affects the paste viscosity which enables stacking of paste layers with a viscosity close to clay pastes. The mixed pastes were cured by heating and UV light to increase mechanical properties. A TG/DTA was performed, and electrical properties were investigated. First experiments with respect to the dielectric properties such as volume resistance, permittivity and dielectric strength revealed promising results and the possibility to use AM techniques for the fabrication of high voltage insulations for electrical machines.
T2 - MaterialsWeek 2021
CY - Online meeting
DA - 07.09.2021
KW - HV-Insulation
KW - Polymer-Ceramic-Composite
KW - Additive manufacturing
PY - 2021
AN - OPUS4-54368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Development of textured multilayer thermoelectric generators based on calcium cobaltite
N2 - Thermoelectric generators can be used as energy harvesters for sensor applications. Multilayer thermoelectric generators (ML-TEGs) are a promising alternative to conventional π-type generators due to their high filling factor, high capability of automated production and the texturing potential during the production process. Calcium cobaltite is a promising thermoelectric oxide (p-type) with highly anisotropic properties. The following study shows the development of a textured unileg ML-TEG using ceramic multilayer technology.
Tape-casting and pressure assisted sintering are applied to fabricate textured calcium cobaltite. Compared to conventional sintering, pressure assisted sintering increases the strength by the factor 10. Thermoelectric properties can be tuned either towards maximum power factor or towards maximum figure of merit depending on the pressure level.
As electrical insulation material, a screen-printable glass-ceramic with high resistivity and adapted coefficient of thermal expansion is developed. From various commercial pastes a metallization with low contact resistance is chosen. The unileg ML-TEG is co-fired in one single step. The demonstrators reach 80% of the simulated output power and the power output is highly reproducible between the different demonstrators (99%). These results provide the first proof-of-concept for fabricating co-fired multilayer generators based on textured calcium cobaltite with high power factor, high density, and high strength.
T2 - Virtual Conference on Thermoelectrics 2021 (VCT)
CY - Online meeting
DA - 20.07.2021
KW - Thermoelectrics
KW - Multilayertechnik
KW - Screen printing
PY - 2021
AN - OPUS4-52993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Commercial LTCC for thin film deposition
N2 - Low-temperature co-fired ceramics (LTCC) are used to fabricate multilayer circuits which are robust in harsh environments. Thick-film technology is well established for the metallization of circuit boards and microsystems. For specific sensor applications, the combination of LTCC and thin-film technology is advantageous to reach higher structure resolutions. Due to the high roughness of as-fired LTCC surfaces compared with silicon-wafers, the deposition of low-defect- films with narrowly specified properties is challenging. There is spare literature about thin films on commercial LTCC comparing different material systems or sintering techniques. For developing thin film sensors on multilayer circuits it is crucial to identify thin-film-compatible commercial LTCC material as well as the crucial surface properties. In this work we evaluate the thin-film capability of different LTCC surfaces.
The as-fired surfaces of free-sintered, constrained-sintered (sacrificial tape), and pressure-assisted sintered commercial LTCCs (DP951, CT708, CT800), as well as respective polished surfaces, were analyzed by tactile and optical roughness measurements and scanning electron microscopy. The thin-film capability of the LTCC surfaces was assessed by sheet resistance and temperature coefficient of resistance (TCR) of deposited Ni thin-film layers. Contrary to the expectations, no correlation between roughness and thin-film capability was found. Ni thin films on constrained sintered DP951 show the lowest sheet resistance and highest TCR within the experimental framework of the as-fired surfaces. The influence of surface morphology on the film properties is discussed.
T2 - KERAMIK 2022 / 97. DKG-Jahrestagung
CY - Online meeting
DA - 7.3.2022
KW - Roughness
KW - Hydrogen sensor
KW - LTCC
PY - 2022
AN - OPUS4-54436
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Herstellung und Charakterisierung keramischer Federn
N2 - Aufgrund ihres spezifischen Eigenschaftsprofils sind keramische Federn attraktiv für Spezialanwendungen in Maschinenanlagen, Metrologie und Sensortechnik. Durch Hartbearbeitung keramischer Hohlzylinder können Spiralfedern mit rechteckigem Windungsquerschnitt präzise gefertigt werden. Dabei kann durch gezielte Auslegung der Federgeometrie die Federkonstante über mehrere Größenordnungen variiert werden. Der Vortrag gibt einen Überblick über den Herstellungsprozess, verschiedene Eigenschaften keramischer Federn und Anwendungsbeispiele.
T2 - Industrieller Arbeitskreis Keramikbearbeitung
CY - Online meeting
DA - 08.04.2022
KW - Keramik
KW - Hartbearbeitung
KW - Federkonstante
PY - 2022
AN - OPUS4-54623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Influence of surface treatment on the strength of a dental zirconia for implants
N2 - Roughening of zirconia dental implants is a common clinical practice to improve ingrowth behavior. It depends on the manufacturer of the implant at which stage of the manufacturing process and by which method the surface is roughened. Systematic studies on this topic are rarely found in the literature. Therefore, the influence of surface treatment on the strength of a dental zirconia was investigated as part of a research project on the development of ceramic implants. The material under test was a commercial zirconia consisting of a Y-TZP matrix and Ce-TZP inclusions in the sintered state. This material is characterized by a slightly higher fracture toughness and slightly reduced strength compared to typical 3Y-TZP. Sets of samples were sandblasted in the white-fired or sintered condition. The ball-on-three-ball-strength of these samples was measured and compared to the strength of as-fired samples and polished samples. The complete study was performed two times for validation of the results. It is found that the average strength of TZP ceramics differs by almost 500 MPa depending on the surface treatment. Conventionally sintered specimens with as-fired surface exhibit a strength of 880 MPa. Sandblasting in the white fired state reduces the strength to 690 MPa. Both polishing and sandblasting in the sintered condition result in an increase in strength to about 1180 MPa. Comparative microstructural investigations, roughness measurements and X-ray phase analyses were carried out to determine the causes of these huge differences in strength. These findings may challenge the practice of white body surface treatment and give reason for further investigations on other commercial dental TZP materials.
T2 - 97th DKG Annual Meeting - CERAMICS 2022
CY - Online meeting
DA - 07.03.2022
KW - Ceramics
KW - Implants
KW - Biaxial strength
PY - 2022
AN - OPUS4-54453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stargardt, Patrick
T1 - Analysis of reaction layers and cooling simulations of co-fired thermoelectric multilayers
N2 - Ceramic multilayer technology is an attractive approach for the cost-effective fabrication of thermoelectric generators. Therefore, efforts are being made to co-sinter two promising thermoelectric oxides, namely calcium cobaltite and calcium manganate. In this study, calcium cobaltite, calcium manganate and release tapes were pressure assisted sintered. A major challenge here is the cracking of calcium manganate during cooling. A relationship between the properties of the release tape used in pressure-assisted sintering and the cracking behavior was observed experimentally.
To understand the origin of failure, formed reaction layers in the multilayer were analyzed by EDX and grazing incident XRD. Based on this analysis, bulk samples were prepared, and thermal expansion and Young's modulus and were determined thereon, if they were not known from the literature. The biaxial strength of the thermoelectric oxides was determined by the ball on three ball method.
The thermal stresses during cooling of different multilayer designs were estimated by finite element simulations. The stresses caused by the reaction layers turned out to be negligible. The FEM study indicated further, and a validation experiment proved, that the thickness of the release tape has the main effect on thermal stresses during cooling in single material. For best performance, the design of a thermoelectric multilayer generator needs to consider thermoelectric performance and thermal stresses during cooling.
T2 - Virtual Conference on Thermoelectrics
CY - Online meeting
DA - 20.07.2021
KW - Ceramic multilayer
KW - Cooling simulations
KW - Thermal stress
KW - Thermoelectric
PY - 2021
AN - OPUS4-52994
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Electric field distribution on ceramic samples during dielectric strength testing
N2 - The dielectric breakdown strength of ceramics strongly depends on the test conditions. Thus, standardized test procedures and thorough documentation are indispensable. However, during dielectric strength testing the breakdown often occurs near the electrode edge or even outside the specified electrode area. This behavior is similarly observed for printed and cylindrical electrodes. The aim of the presented study was to calculate the electric field strength distribution in a ball-on-plate testing setup for metallized samples and to correlate the field distribution with the observed breakdown locations. Small misalignments in the test setup were also considered in the simulations. Furthermore, the field strength at the breakdown Location should be compared to the experimentally determined dielectric strength. Therefore, Finite Element Models of several test conditions with varying printed electrode areas and sample thicknesses were created and electrostatic calculations of the electric field Distribution were performed. The simulation results were compared to experimental data. Alumina (96 %) was used as test material. The calculations show that the electric field strength maxima match the experimentally observed locations of breakdown. Without any fitting of the model, the maximum calculated field strength is in reasonable agreement with the experimental dielectric strength. The FE analysis is a helpful tool to understand the observations in experimental dielectric strength testing.
T2 - CERAMICS 2021 / 96th DKG Annual Meeting
CY - Online Meeting
DA - 19.04.2021
KW - Dielectric breakdown
KW - Dielectric strength
KW - Electric field strength
KW - Ceramics
PY - 2021
AN - OPUS4-52512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stargardt, Patrick
T1 - Dielectric properties of plasma sprayed coatings for insulation application
N2 - Thermal spraying provides a rapid method for additive deposition of various ceramics as electrical insulation in applications where polymers are not suitable. New applications in complex shaped additive manufactured metal parts are emerging for example in large scale electrical devices. Microstructural and dielectric evaluation of coatings is crucial to the employment of such free-form processes. The properties and microstructure of the plasma sprayed alumina coatings are compared with dense reference samples of the same powder produced by spark plasma sintering (SPS). To obtain dense bulk samples from the coarse alumina powder for spray coating, SPS is used.
Samples are fabricated by atmospheric plasma spraying (APS) of commercially available alumina powder (d50 = 33 µm) on copper substrates and by SPS of the same powder. Microstructure and porosity were analyzed by optical microscopy and scanning electron microscopy (SEM). Phase compositions were determined by X-ray diffraction (XRD). Dielectric properties such as DC resistance, dielectric strength, dielectric loss, and relative permittivity were determined according to the standards. The microstructure and dielectric properties of the coating and bulk material are compared to assess whether the coating is suitable for use in electrical insulation application.
T2 - Ceramics in Europe 2022
CY - Krakow, Poland
DA - 10.07.2022
KW - Dielectric characterization
KW - Atmospheric plasma spraying
KW - Spark plasma sintering
KW - Electrical insulation
PY - 2022
AN - OPUS4-55328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Ontologies and data pipelines - a field report from the development of multilayer ferrite inductors
N2 - Digitalization is a current and prominent cross-cutting topic in ceramics and materials science in general. Many research initiatives and levels of significance are associated with this term. The Initiative Platform MaterialDigital (PMD), for example, aims to create a material data space filled with semantically linked data. The concept envisages that semantic relationships between the data are described as ontologies and that processing of data takes place via automated data pipelines. Various research projects from all areas of materials science are working on the implementation of this concept based on specific use cases. In the project presented here, the use case is the development of multilayer ferrite inductors as passive microelectronic components. The inductors are fabricated by ceramic multilayer technology and co-firing of metallized tapes of NiCuZn ferrite and a dielectric base material. Investigations focus on the effects of fabrication technology on the permeability of the ferrite. A data pipeline is introduced that automatically processes the unstructured experimental data into structured, machine-readable and semantically linked data. The concrete implementation of the data pipeline and a domain ontology is presented using examples. Challenges and advantages are discussed.
T2 - CERAMICS 2024 / 99th DKG Annual Meeting
CY - Höhr-Grenzhausen, Germany
DA - 09.09.2024
KW - Ontology
KW - Ceramic multilayer
KW - MaterialDigital
PY - 2024
AN - OPUS4-61037
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stargardt, Patrick
T1 - Comparison of design concepts for ceramic oxide thermoelectric multilayer generators
N2 - Multilayer thermoelectric generators are a promising perspective to the conventional π-type generators. Ceramic multilayer technology is well established for production of microelectronics and piezo-stacks. Key features of ceramic multilayer technology are full-automation, cost-effectiveness, and the co-firing of all materials in one single step. This requires similar sintering temperatures of all used materials. The development of multilayer thermoelectric generators is a subject of current research due to the advantages of this technology. One of the challenges is the compatibility of the different materials with respect to the specific design.
The presented study compares three different designs of multilayer generators based on a given set of material properties. Dualleg, unileg and transverse multilayer generators are compared to conventional π-type generators., the designs are evaluated regarding the expected maximum output power and power density using analytical calculations and FEM simulations. Additionally, the complexity of the production process and material requirements are assessed and design optimizations to simplify production are discussed.
Besides the theoretical aspects, unileg multilayer generator prototypes were produced by tape-casting and pressure-assisted sintering. These prototypes are compared to other multilayer generators from literature regarding the power factors of the used material system and the power density. Improvements of the power output by design optimizations are discussed
T2 - 18th European Conference on Thermoelectrics
CY - Barcelona, Spain
DA - 13.09.2022
KW - Thermoelectric oxides
KW - Thermoelectric generator design
PY - 2022
AN - OPUS4-55820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Chemical resistance of commercial LTCC against thin film etching media
N2 - Low-temperature co-fired ceramics (LTCC) are used to fabricate robust multilayer circuits. Typically, thick-film technology is applied for metallization. For specific sensor applications, thin films are deposited directly on the as-fired LTCC-surface. These deposited thin films are structured either by lift-off or by etching. The latter is less error-prone and thus preferred in industry provided the selected materials allow it.
200 nm Ni-thin films were deposited on three different commercial constrained-sintered LTCC (CT708, CT800 and DP951) by electron beam physical vapour deposition. The thin-films were structured by covering corresponding sections with a UV-curable photo resisn and subsequent etching of the uncovered surface, leaving behind the desired structure. The etched Ni-thin film showed high difference in failure rate and sheet resistance regarding the used LTCC-material. DP951 had the lowest sheet resistance and no failure, whereas the CT800 had a failure rate of 40 %. The LTCC with high failure rate showed a strong chemical attack by the used etching medium. To address this phenomenon, the chemical resistance of the three different commercial LTCC (CT708, CT800 and DP951) against four different commonly used etching media (sulphuric acid, phosphoric acid, aqua regia, and hydrofluoric acid) is investigated. The dissolved ions are analyzed by ICP-OES to correlate the LTCC-composition and its chemical resistance.
T2 - KERAMIK 2023 / 98. DKG-Jahrestagung
CY - Jena, Germany
DA - 27.03.2023
KW - Glass-ceramics
KW - Hydrogen sensors
KW - Acids
PY - 2023
AN - OPUS4-57273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hertwig, Andreas
T1 - A multi-method study of femtosecond laser modification and ablation of amorphous hydrogenated carbon coatings
N2 - We report here the optical constants of ECR (MW) and RF generated a-C:H layers before and after laser irradiation. The work is described in the following publication:
https://doi.org/10.1007/s00339-024-07980-z
The data uploaded are the optical constants (n and k) of the a-C:H layers before (base) and after (ROIx) laser irradiation. Please see the article for the nomenclature of the data and for the methods applied ot produce the layers, laser shots, and OK data.
KW - Spectroscopic ellipsometry
KW - Amorphous hydrogenated carbon layers
KW - Laser materials processing
KW - Correlative imaging spectroscopy
PY - 2024
DO - https://doi.org/10.5281/zenodo.13928596
PB - Zenodo
CY - Geneva
AN - OPUS4-61855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sachse, René
T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrOx films revealed under realistic OER conditions
N2 - Hydrogen production via water electrolysis will be an essential cornerstone in development of sustainable, fossil-free fuel and chemical production on a global scale. The activity and stability of each catalyst is highly dependent on the properties of the coating, i.e., phase composition, crystallinity, accessible surface area, and many other factors. The key to developing improved catalysts is a better understanding of the relationships between their performance, stability, and physicochemical properties. However, these relationships can be complex and are also strongly influenced by the reaction environment. Therefore, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. However, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities.
We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts, a suitable sample environment, and a deep understanding of the appropriate model development, as well as concise cross validation with numerous other analytical techniques.
The method was developed and validated by analyzing a calcination series (300 – 600 °C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric (ECSE) analysis revealed during OER the change of optical and electronic properties, i.e. the dielectric functions, resistivity and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from ε1 and ε2 from SE measurements reveal a direct correlation with electrochemical activities in OER.
In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution at different potentials.
T2 - 11th Workshop Ellipsometry (WSE 11)
CY - Steyr, Austria
DA - 06.09.2021
KW - Ectrocatalysis
KW - Mesoporous iridium oxide films
KW - Non-destructive operando analysis
KW - Oxygen evolution reaction
KW - Spectroscopic ellipsometry
PY - 2021
AN - OPUS4-53915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ren, L.
A1 - Pollard, A.
A1 - Hodoroaba, Vasile-Dan
T1 - Measurement of Lateral Size of Graphene Oxide Flakes by SEM - An Update of the VAMAS TWA 41 Project P13
N2 - The progress of the VAMAS interlaboratory comparison Project P13 "Lateral size of graphene oxide flakes by SEM" within the Technical Working Area 41 "Graphene and Related 2D Materials" is presented. The challenges at sample preparation on substrates for accurate measurement and image analysis as well as two different image analysis approaches, containing exact guidance how to measure the main descriptors for the lateral size measurement of the imaged graphene oxide flakes with Scanning Electron Microscopy are described. Discrepancies are explained. The inclusion of the results into the corresponding ISO technical specification CD/TS 23879 is also discussed and planned, in relation with the AFM part.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 50th Steering Committee Meeting
CY - London, United Kingdom
DA - 15.09.2025
KW - VAMAS
KW - Interlaboratory comparison
KW - Electron microscopy
KW - Lateral size
KW - Graphene oxide flakes
PY - 2025
UR - https://www.vamas.org/twa41/documents/2023_vamas_twa41_project13_GO_SEM.pdf
AN - OPUS4-64228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, M.
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Oxidative ageing of elastomers: experiment and modelling
N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of 125 ◦ C and 150 ◦ C. To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments.
KW - Compression Set
KW - Compression stress relaxation
KW - Modelling
KW - Ageing
KW - Microhardness
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609332
DO - https://doi.org/10.1007/s00161-022-01093-9
VL - 36
SP - 289
EP - 297
PB - Springer Nature
AN - OPUS4-60933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Hörenz, Christoph
A1 - Pellegrino, F.
A1 - Maurino, V.
A1 - Durand, B.
A1 - Taché, O.
T1 - Nanoparticle size, shape, and concentration measurement at once – two VAMAS pre-standardization projects ready to start
N2 - A case study on the TEM analysis of the size and shape distribution of TiO2 bipyramidal nanoparticles prepared on TEM grids was included in the recently published ISO standard ISO 21363. It was agreed to organize at a later stage a second inter-lab comparison with the nanoparticles distributed to the participants as a liquid suspension. Protocols for uniform nanoparticle deposition on suited supports developed and optimized within the EMPIR nPSize project are also prepared to be distributed. For this, we have chosen the VAMAS platform (www.vamas.org) which offers an excellent international infrastructure of laboratories with high competence in nanoparticle measurement. The VAMAS technical working area dedicated to nanoparticle measurement is TWA 34 ‘Nanoparticle populations’. For this type of nanoparticles, the size and shape distributions are the primary parameters to be reported. Due to the good deposition protocols developed, an automated image analysis is enabled (in contrast to the manual analysis of irregular TiO2 nanoparticles.
In parallel with the TiO2 nanoparticle exercise, two spherical SiO2 nanoparticle samples with bi-modal size distributions (nominal relative number concentrations of 1:1 and 10:1) are prepared for a second VAMAS inter-lab comparison. Here, the nanoparticle concentration is the primary parameter to be measured. For the imaging methods it is targeted to measure the relative nanoparticle concentrations of the two modes. For the absolute nanoparticle concentration to be measured by imaging methods it is necessary to control the volume of the liquid suspension deposited on the substrate and to obtain such a homogeneous nanoparticle deposition on the substrate which allows to count (or extrapolate) all the deposited particles.
KW - Electron microscopy
KW - Inter-laboratory comparison
KW - Nanoparticles
KW - SiO2
KW - TiO2
KW - VAMAS
PY - 2021
DO - https://doi.org/10.1017/S1431927621008126
VL - 27
IS - Suppl. 1
SP - 2250
EP - 2251
PB - Cambridge University Press
AN - OPUS4-53124
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - EMPIR nPSize Improved Traceability Chain of Nanoparticle Size Measurement - Outcomes for the Strategy/Metrology Groups of ISO/TC 229 Nanotechnologies
N2 - The main outcomes of the EMPIR project nPSize are presented and the suitability of the new capabilities (e.g. reference materials, measurement procedures, VAMAS inter-laboratory comparisons) to be standardized and implemented in accredited analytical laboratories is discussed. Complementation and/or filling gaps of published and ongoing standardisation projects on size, shape and number concentration measurements under ISO/TC 229/JWG 2 are offered.
T2 - Annual Meeting of ISO/TC 229 Nanotechnologies - Strategy and Metrology Groups
CY - Online meeting
DA - 06.11.2020
KW - Nanoparticles
KW - Size
KW - nPSize
KW - Inter-laboratory comparison
KW - ISO/TC 229
KW - VAMAS
PY - 2020
AN - OPUS4-51544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Overview of ongoing long-term ageing investigations on elastomer seals
N2 - At the Bundesanstalt für Materialforschung und -prüfung (BAM) in Division 3.4 Safety of Storage Containers, one of our tasks is to evaluate the safety of containers designed for disposal of low and intermediate radioactive waste. As such containers might be transported before and stored until disposal, safe enclosure of the radioactive inventory is important for this time span. Elastomer O-rings are widely used as barrier seals in these containers. Thus, as for many other applications, an understanding of the practical effects of ageing degradation on elastomer seals during long-term exposure is mandatory for predicting the lifetime of such components. According to a long-term test programme on three kinds of rubbers (EPDM and FKM (relevant for application), HNBR (for comparison)), over several years we have studied the degradation and the change of mechanical properties (e.g. hardness, strain at break) at four different ageing temperatures (75 °C, 100 °C, 125 °C and 150 °C) as well as the change of sealing properties. Continuous and intermittent compression stress relaxation (CSR) measurements were performed in order to investigate the respective contribution of crosslinking and chain scission to the observed degradation effects. Thus, the degradation kinetics and mechanisms could be resolved more clearly. For assessing the seal performance, compression set (CS) and leakage rate measurements were conducted. The experimental results showed that the O-rings remained leak-tight under purely static conditions even when CSR, CS and mechanical properties already indicated far advanced degradation. For this reason, a modified leakage test involving a small and rapid partial decompression of the seal was developed that enabled determining an end-of-lifetime criterion for O-rings with a safety margin for thermal shrinkage and vibrations.
KW - Seal
KW - O-Ring
KW - Ageing
KW - Component tests
PY - 2020
SN - 1863-7116
VL - 15
IS - 3
SP - 146
EP - 151
PB - Gupta
CY - Ratingen
AN - OPUS4-51161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feltin, N.
A1 - Crouzier, L.
A1 - Delvallée, A.
A1 - Pellegrino, F
A1 - Maurino, V.
A1 - Bartczak, D.
A1 - Goenaga-Infante, H.
A1 - Taché, O.
A1 - Marguet, S.
A1 - Testard, F.
A1 - Artous, S.
A1 - Saint-Antonin, F.
A1 - Salzmann, Christoph
A1 - Deumer, J.
A1 - Gollwitzer, C.
A1 - Koops, R.
A1 - Sebaïhi, N.
A1 - Fontanges, R.
A1 - Neuwirth, M.
A1 - Bergmann, D.
A1 - Hüser, D.
A1 - Klein, T.
A1 - Hodoroaba, Vasile-Dan
T1 - Metrological Protocols for Reaching Reliable and SI-Traceable Size Results for Multi-Modal and Complexly Shaped Reference Nanoparticles
N2 - The study described in this paper was conducted in the framework of the European nPSize project (EMPIR program) with the main objective of proposing new reference certified nanomaterials for the market in order to improve the reliability and traceability of nanoparticle size measurements. For this purpose, bimodal populations as well as complexly shaped nanoparticles (bipyramids, cubes, and rods) were synthesized. An inter-laboratory comparison was organized for comparing the size measurements of the selected nanoparticle samples performed with electron microscopy (TEM, SEM, and TSEM), scanning probe microscopy (AFM), or small-angle X-ray scattering (SAXS). The results demonstrate good consistency of the measured size by the different techniques in cases where special care was taken for sample preparation, instrument calibration, and the clear definition of the measurand. For each characterization method, the calibration process is described and a semi-quantitative table grouping the main error sources is proposed for estimating the uncertainties associated with the measurements. Regarding microscopy-based techniques applied to complexly shaped nanoparticles, data dispersion can be observed when the size measurements are affected by the orientation of the nanoparticles on the substrate. For the most complex materials, hybrid approaches combining several complementary techniques were tested, with the outcome being that the reliability of the size results was improved.
KW - Certified reference nanomaterials
KW - Traceable nanoparticle size measurements;
KW - Hybrid metrology
KW - Scanning probe microscopy
KW - Small-angle X-ray scattering
KW - Electron microscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571902
DO - https://doi.org/10.3390/nano13060993
SN - 2079-4991
VL - 13
IS - 6 - Special Issue "Identification and Quantification of Nanomaterials"
SP - 1
EP - 25
PB - MDPI
CY - Basel, CH
AN - OPUS4-57190
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Terborg, R.
A1 - Hodoroaba, Vasile-Dan
T1 - Determination of Thin Film Thickness and Composition using Energy Dispersive EPMA
N2 - Electron probe microanalysis (EPMA)is a non-destructive technique which assumes a sample of homogenous (bulk) chemical composition and can, therefore, not be used for thin film samples. However, in combination with one of the possible thin film software packages, STRATAGEM, the thickness as well as the composition of such films on a substrate can be determined.
This has been demonstrated for FeNi on Si and SiGe on Al2O3 film systems. For both systems five samples with different elemental composition and a reference were produced and characterised by the Korean research institute KRISS using inductively coupled plasma mass spectrometry (ICP-MS), Rutherford backscattering (RBS), and transmission electron microscopy (TEM).
In 2021, a new and open source thin film evaluation programme called BADGERFILM has been released. It can also be used to determine thin film composition and thickness from intensity ratios of the unknown sample and standards (k-ratios).
In this contribution, we re-evaluated the data acquired for the FeNi and SiGe systems using the BADGERFILM software package and compared the resulting composition and thickness with the results of the established STRATAGEM software and other reference methods. With the current evaluation, the BADGERFILM software shows good agreement with the composition and thickness calculated by STRATAGEM and provided by the KRISS.
These results between two well-known layered material systems analysed with available conventional EMPA approaches (STRATAGEM and direct thickness measurement by TEM) and a new one (BADGERFILM) proves that reliable non-destructive thin film analysis is possible. In this way, we validate the performance of the new software, which is not at all self-explanatory for such
complex quantification algorithms lying behind the final quantified results.
T2 - EMAS 2023 - 17th European Workshop on Modern Developments and Applications in Microbeam Analysis
CY - Krakow, Poland
DA - 07.05.2023
KW - Thin films
KW - BADGER film
KW - Electron probe microanallysis (EPMA)
KW - FeNi thin film
KW - Al2O3 thin films
PY - 2023
UR - https://www.microbeamanalysis.eu/events/event/60-emas-2023-17th-european-workshop-on-modern-developments-and-applications-in-microbeam-analysis
AN - OPUS4-57484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Knowledge, Information and Data Readiness Levels (KaRL) approach for Nanorisk Governance
N2 - Nanomaterials may have brought many beneficial innovations with them in our daily lives and and have become indispensable for the society. However, one needs to be concerned of the risks which are still unknown and not sufficietly studied and therefore there is a need for a nanorisk governance. At the core of nanorisk governance is gathering, processing and analysing reliable data which will be used for decision making. The challenge is to assure data reliability and transform it into knowledge. To address this challenge, we used analogy to technology readiness level (TRL) approach (developed by NASA), and elaborated knowledge readiness level (KaRL). KaRL is a nine-scale system to categorize data and knowledge (documents) into levels of readiness for particular purposes and to enhance readiness level by using quality and completeness filters, compliance requirements, nanorisk-related tools, stakeholders’ input. By our approach we addressed key issues in nanotechnology such as societal and ethical concerns, circular economy and sustainability, traceability of data, knowledge and decisions.
T2 - EC - HORIZON EUROPE NMBP-13 Joint Conference Risk Governance of nanotechnology
CY - Online meeting
DA - 12.04.2021
KW - Knowledge Readiness Level
KW - Nanorisk
KW - Nanomaterials
KW - Data
PY - 2021
AN - OPUS4-52471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hülagü, Deniz
A1 - Tobias, Charlie
A1 - Climent Terol, Estela
A1 - Gojani, Ardian
A1 - Rurack, Knut
A1 - Hodoroaba, Vasile-Dan
T1 - Generalized Analysis Approach of the Profile Roughness by Electron Microscopy with the Example of Hierarchically Grown Polystyrene–Iron Oxide–Silica Core–Shell–Shell Particles
N2 - The roughness as a property of core–shell (CS) microparticles plays a key role in their functionality. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task with approaches using electron microscopy images being scarce and showing pronounced differences in terms of methodology and results. This work presents a generalized method for the reliable roughness determination of nonplanar specimens such as CS particles from electron microscopic images, the method being robust and reproducible with a high accuracy. It involves a self-written software package (Python) that analyzes the recorded images, extracts corresponding data, and calculates the roughness based on the deviation of the identified contour. Images of single particles are taken by a dual mode scanning electron microscopy (SEM) setup which permits imaging of the same field-of-view of the sample with high resolution and surface sensitive in SE InLens mode as well as in transmission mode (TSEM). Herein, a new type of polystyrene core–iron oxide shell–silica shell particles is developed to serve as a set of lower micrometer-sized study objects with different surface roughness; the analysis of their images by the semiautomatic workflow is demonstrating that the particles’ profile roughness can be quantitatively obtained.
KW - Core–shell particles
KW - Image analysis
KW - Nanoparticles
KW - Roughness
KW - SEM
KW - transmission mode
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542576
DO - https://doi.org/10.1002/adem.202101344
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-54257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Towards automated electron microscopy image segmentation for nanoparticles of complex shape by convolutional neural networks
N2 - In this contribution different ways are explored with the aim to generate suitable training data for ‘non-ideal’ samples using various approaches, e.g., computer-generated images or unsupervised learning algorithms such as generative adversarial networks (GANs). We used these data to train simple CNNs to produce segmentation masks of SEM images and tested the trained networks on real SEM images of complex nanoparticle samples. The novel use of CNN for the automated analysis of the size of nanoparticles of complex shape and with a high degree of agglomeration has proved to be a promising tool for the evaluation of particle size distribution on a large number of constituent particles. Further development and validation of the preliminary model, respectively larger training and validation data sets are necessary.
T2 - Microscopy and Microanalysis 2020
CY - Online meeting
DA - 03.08.2020
KW - Nanoparticles
KW - Automatisation
KW - Image segmentation
KW - Convolutional neural networks
KW - Electron microscopy
PY - 2020
AN - OPUS4-51114
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Kim, K. J.
A1 - Yu, H.
A1 - Lee, S. M.
A1 - Kwon, J. H.
A1 - Ruh, H.
A1 - Radnik, Jörg
A1 - Archanjo, B. S.
A1 - Annese, E.
A1 - Damasceno, J. C.
A1 - Achete, C. A.
A1 - Yao, Y.
A1 - Ren, L.
A1 - Gao, H.
A1 - Windover, D.
A1 - Matsuzaki, H.
A1 - Azuma, Y.
A1 - Zhang, L.
A1 - Fujimoto, T.
A1 - Jordaan, W. A.
A1 - Reed, B.
A1 - Shard, A. G.
A1 - Cibik, L.
A1 - Gollwitzer, C.
A1 - Krumrey, M.
T1 - Final report of CCQM-K157 for the measurement of the amount of substance of HfO2 expressed as the thickness of nm films
N2 - The key comparison CCQM-K157 for the thickness measurement of HfO2 films was performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The aim of CCQM-K157 is to establish the measurement traceability and to ensure the equivalency in the measurement capability of national metrology institutes for the thickness measurement of HfO2 films.
In this key comparison, the thicknesses of six HfO2 films with the nominal thickness range from 0.7 nm to 6 nm were compared by x-ray photoelectron spectroscopy (XPS), x-ray reflectometry (XRR), transmission electron microscopy (TEM), spectroscopic ellipsometry (SE) and medium energy ion scattering spectrometry (MEIS).
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
KW - CCQM
KW - Thin Films
KW - HfO2
KW - thickness
KW - XPS
PY - 2023
DO - https://doi.org/10.1088/0026-1394/60/1A/08010
VL - 60
SP - 08010
PB - IOP
AN - OPUS4-63049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Jungnickel, H.
A1 - Tentschert, J.
A1 - Luch, A.
A1 - Sogne, V.
A1 - Maier, F.
A1 - Burr, L.
A1 - Schmid, D.
A1 - Yoon, T.-H.
A1 - Petters, R.
A1 - Briffa, S.M.
A1 - Valsami-Jones, E.
T1 - Automation and Standardization—A Coupled Approach Towards Reproducible Sample Preparation Protocols for Nanomaterial Analysis
N2 - Whereas the characterization of nanomaterials using different analytical techniques is often highly automated and standardized, the sample preparation that precedes it causes a bottleneck in nanomaterial analysis as it is performed manually. Usually, this pretreatment depends on the skills and experience of the analysts. Furthermore, adequate reporting of the sample preparation is often missing. In this overview, some solutions for techniques widely used in nano-analytics to overcome this problem are discussed. Two examples of sample preparation optimization by au-tomation are presented, which demonstrate that this approach is leading to increased analytical confidence. Our first example is motivated by the need to exclude human bias and focuses on the development of automation in sample introduction. To this end, a robotic system has been de-veloped, which can prepare stable and homogeneous nanomaterial suspensions amenable to a variety of well-established analytical methods, such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), field-flow fractionation (FFF) or single-particle inductively coupled mass spectrometry (sp-ICP-MS). Our second example addresses biological samples, such as cells exposed to nanomaterials, which are still challenging for reliable analysis. An air–liquid interface has been developed for the exposure of biological samples to nanomaterial-containing aerosols. The system exposes transmission electron microscopy (TEM) grids under reproducible conditions, whilst also allowing characterization of aerosol composition with mass spectrometry. Such an approach enables correlative measurements combining biological with physicochemical analysis. These case studies demonstrate that standardization and automation of sample preparation setups, combined with appropriate measurement processes and data reduction are crucial steps towards more reliable and reproducible data.
KW - Sample preparation
KW - Automation
KW - Nanomaterial analysis
KW - Standardization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543988
DO - https://doi.org/10.3390/molecules27030985
VL - 27
IS - 3
SP - 1
EP - 22
PB - MDPI
AN - OPUS4-54398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Hodoroaba, Vasile-Dan
A1 - Fontanges, R.
A1 - Delvallée, A.
A1 - Deumer, J.
A1 - Salzmann, C.
A1 - Crouzier, L.
A1 - Gollwitzer, C.
A1 - Klein, T.
A1 - Koops, R.
A1 - Sebaihi, N.
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Artous, S.
A1 - Taché, O.
A1 - Feltin, N.
T1 - Report on full algorithm sequences for nanoparticle detection and size measurement as developed on both a physical basis and by machine learning
N2 - he main objective of the nPSize project is to improve the measurement capabilities for nanoparticle size based on both measurement methods traceable to SI units and new reference materials. Two basic approaches have been used in order to develop measurement procedures resulting in traceable results of the nanoparticle size distribution: physical modelling for the methods used in the project (TSEM, SEM, AFM and SAXS) and machine learning.
Physical modelling: In this part, the physical models associated with different shape measurements for the techniques TSEM, SEM, AFM and SAXS have been collected and further developed with the aim to simulate the resulting signal as measured by the individual methods. Uncertainties and traceability associated with each model were investigated and evaluated. In the following, the progress on these physical models is reported for each individual method.
Machine Learning modelling: The aim of this part is to use machine learning to enable automatic measurement of nanoparticle shape from expert a-priori information only. No physical model will be used as a-priori information in this task.
The accuracy and traceability of the size results obtained by each technique will be analyzed and compared with the physical modelling. A machine learning database will then be used to create automatic detection algorithms.
KW - Nanoparticles
KW - Particle size distribution
KW - SEM
KW - TSEM
KW - TEM
KW - SAXS
KW - AFM
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546531
DO - https://doi.org/10.5281/zenodo.5807864
SP - 1
EP - 20
PB - Zenodo
CY - Geneva
AN - OPUS4-54653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Vladár, A. E.
A1 - Hodoroaba, Vasile-Dan
ED - Hodoroaba, Vasile-Dan
ED - Unger, Wolfgang
ED - Shard, A. G.
T1 - Characterization of nanoparticles by scanning electron microscopy
N2 - In this chapter sample preparation, image acquisition, and nanoparticle size and shape characterization methods using the scanning electron microscope (SEM) in reflective and transmitted working modes are described. These help in obtaining reliable, highly repeatable results. The best solutions vary case-by-case and depend on the raw (powdered or suspension) nanoparticle material, the required measurement uncertainty and on the performance of the SEM.
KW - Nanoparticles
KW - Sample preparation
KW - Electron microscopy
KW - SEM
KW - Size measurement
KW - Shape
KW - Threshold
PY - 2020
SN - 978-0-12-814182-3
DO - https://doi.org/10.1016/B978-0-12-814182-3.00002-X
SP - 7
EP - 27
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kömmling, Anja
A1 - Grelle, Tobias
A1 - Jaunich, Matthias
A1 - Goral, Milan
A1 - Wolff, Dietmar
T1 - Three-dimensional thermal expansion of neat and irradiated (U)HMWPE materials at elevated temperatures
N2 - The thermal expansion of polymeric parts can be an issue in many applications where the available space is limited, or exact dimensions of the part are required. For this study, a device was designed and built that allowed measuring the thermal expansion simultaneously in all three spatial directions on cubic samples with real-scale dimensions (78 mm edge length). The results are shown between 25 °C and 125 °C for two PE materials, one HMWPE and one tempered UHMWPE, for non-irradiated samples as well as cubes that have been irradiated with 100 and 400 kGy. The results measured with the new device were very similar to those measured with conventional thermo-mechanical analysis equipment and to literature data of UHMWPE. The HMWPE material shows a much larger thermal expansion coefficient in one direction compared to the other two directions during the first heating due to frozen stresses from the pressing step during material manufacturing. These stresses are mostly released by the expansion during the first heating, so that the expansion during the second heating is more uniform. The overall volumetric expansion is the same for both heating runs. By contrast, the tempered UHMWPE material shows no significant difference between first and second heating run, as the stresses from processing could already relax in the tempering step. The irradiation treatment does not affect the values significantly for the given test set-up.
KW - Lupolen
KW - Ultra high molecular weight polyethylene
KW - GUR
KW - Coefficient of thermal expansion
KW - High temperature
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563987
DO - https://doi.org/10.1016/j.polymertesting.2022.107841
SN - 0142-9418
VL - 117
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-56398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arinchtein, A.
A1 - Ye, M.-Y.
A1 - Yang, Q.
A1 - Kreyenschulte, C.
A1 - Wagner, Andreas
A1 - Frisch, M.
A1 - Brückner, A.
A1 - Kondratenko, E.
A1 - Kraehnert, R.
T1 - Dynamics of Reaction-Induced Changes of Model-Type Iron Oxide Phases in the CO2-Fischer-Tropsch-Synthesis
N2 - Iron-based catalysts are employed in CO2-FTS due to their ability to convert CO2 into CO in a first step and their selectivity towards higher hydrocarbons in a second CO hydrogenation step. According to the literature, iron carbides represent the active phase for hydrocarbon formation and are claimed to emerge in the presence of CO. We propose nanostructured FeOx films as model systems to assess information about the complex phase transformations during CO2-FTS. Mesoporous hematite, ferrihydrite, maghemite, maghemite/magnetite films were exposed to CO2-FTS atmospheres at 20 bar and 300°C. Up to three distinct phases were observed depending on the timeon-stream (TOS): a sintered maghemite/magnetite phase, a carbidic core-shell structure, and a low-crystalline, needle-type oxide phase. Our findings indicate that the formation of an intermediary maghemite/magnetite phase, predominant after short TOS (30 h), precedes the evolution of the carbide phase.
Yet, even after prolonged TOS (185 h), no full conversion into a bulk carbide is observed.
KW - Nanostructured FeOx films
KW - CO2
KW - Scanning Auger Spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549709
DO - https://doi.org/10.1002/cctc.202200240
SN - 1867-3880
VL - 14
IS - 14
SP - 1
EP - 11
PB - Wiley-VCH
AN - OPUS4-54970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Mech, A.
A1 - Rauscher, H.
A1 - Babick, F.
A1 - Hodoroaba, Vasile-Dan
A1 - Wohlleben, W.
A1 - Marvin, H.
A1 - Weigel, S.
A1 - Brüngel, R.
A1 - Friedrich, C. M.
T1 - The NanoDefine Methods Manual - Part 1: The NanoDefiner Framework and Tools
N2 - The present series of reports, the NanoDefine Methods Manual, has been developed within the NanoDefine project 'Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial', funded by the European Union's 7th Framework Programme, under grant agreement 604347.
In 2011 the European Commission (EC) published a recommendation for a definition of the term 'nanomaterial', the EC NM Definition, as a reference to determine whether an unknown material can be considered as a 'nanomaterial' for regulatory purposes1. One challenge is the development of methods that reliably identify, characterize and quantify nanomaterials (NM) both as substances and in various products and matrices.
The overall goal of NanoDefine was to support the implementation of the EC NM Definition. It can also support the implementation of any NM definition based on particle size. The project has developed an integrated approach, which allows identifying any material as a nano- or not a nanomaterial according to the EC NM Definition. NanoDefine explicitly supported the governance challenges associated with the implementation of legislation concerning nanomaterials by:
- addressing the issues on availability of suitable measuring techniques, reference materials, validated methods, acceptable to all stakeholders (authorities, policy makers, commercial firms),
- developing an integrated and interdisciplinary approach and a close international co-operation and networking with academia, commercial firms and standardization bodies.
Thus, the NanoDefine Methods Manual provides guidance on practical implementation of the EC NM Definition throughout the nanomaterial characterization process, and on the characterization techniques employed as well as their application range and limits. It assists the user in choosing the most appropriate measurement method(s) to identify any substance or mixture for a specific purpose, according to the EC NM Definition of a nanomaterial. The NanoDefine project also explored how to assess a material against the criteria of the definition through proxy solutions, i.e. by applying measurement techniques that indirectly determine the x50. Those findings were developed through empirically based scientific work and are included in Part 1 of this Manual. As they go beyond the text of the EC NM Definition, they may be used as practical approach to indicate whether a material is a nanomaterial or not, but keeping in mind that they should not be taken as recommendation for the implementation of the EC NM Definition in a regulatory context.
The NanoDefine Methods Manual consists of the following three parts:
Part 1: The NanoDefiner Framework and Tools
Part 2: Evaluation of Methods
Part 3: Standard Operating Procedures (SOPs)
Part 1 covers the NanoDefiner framework, general information on measurement methods and performance criteria and tools developed by NanoDefine such as a materials categorisation system, a decision support flow scheme and an e-tool.
Part 2 discusses the outcome of the evaluation of the nanomaterials characterisation methods for measuring size.
Part 3 presents the 23 Standard Operating Procedures developed within the NanoDefine project.
The current document is part 1.
KW - Nanomaterial
KW - Nanoparticles
KW - NanoDefine
KW - Nanoparticle size distribution
KW - Nanomaterial classification
KW - Framework
KW - Tools
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503699
SN - 978-92-76-11950-0
DO - https://doi.org/10.2760/55181
SN - 1831-9424
SP - 1
EP - 89
PB - Publications Office of the European Union
CY - Luxembourg
AN - OPUS4-50369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Abram, Sarah-Luise
A1 - Rühle, Bastian
A1 - Hodoroaba, Vasile-Dan
T1 - Understanding Correlative Electron Microscopy Imaging with SEM, STEM-in-SEM and TEM for the Accurate Characterization of Size and Shape of Iron Oxide Nanoparticles
N2 - The recently certified reference material (CRM) BAM-N012 as cubical iron oxide FeOx nanoparticles (NPs) of 8 nm area equivalent square edge length (ESL) and the RM candidate BAM-N013 as nearly spherical NPs of 22 nm size were analyzed in detail by electron microscopy (EM).
For the metrological characterization with SEM, STEM in SEM and TEM, the understanding of the imaging contrasts and sensitivities, and the correct interpretation of the (art)effects which are inherent to each detection mode is necessary.
The same sample areas with NPs deposited on a TEM grid were analyzed by two SEM acquisition modes, i. e. SE InLens and STEM in SEM using a dedicated transmission sample holder, and further, correlatively, analyzed with TEM.
With increasing kV, SE InLens shows increasing particle size (unless overcharging at the particle boundaries is filtered), as a known effect. For STEM-in-SEM the particle size decreases significantly and individual particles are identified easier (at 2 kV only a few single particles can be detected automatically).
❑ Documentation of the sample preparation and measurement conditions (including optimization process) is important for reproducibility.
❑ Plasma cleaning, analysis in the transmission mode at SEM is recommended for FeOx NPs.
❑ Selection of the threshold algorithm can significantly alter the reported ECD.
KW - Nanoparticles
KW - Iron oxide
KW - Electron microscopy
KW - Reference materials
KW - Particle size distribution
KW - Imaging
PY - 2024
DO - https://doi.org/10.1093/mam/ozae044.339
VL - 30
IS - Supplement_1
SP - 710
EP - 711
PB - Oxford University Press (OUP)
AN - OPUS4-61007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Advanced Characterization of the Surface Morphology and Chemistry within nano@BAM
N2 - Both essential aspects of the surface of solid matter, its morphology and chemistry, are studied traditionally at BAM starting in the 60’s with different cyclical research focus areas, mostly related either to applicative research or method development. In the recent years, the focus has shifted almost exclusively to the nano-analytics of advanced materials such as complex nanoparticles, (ultra)thin films/coatings, nanocomposites, 2D materials, energy materials, etc. This is also the reason why BAM has established recently the new Competence Center nano@BAM (www.bam.de/Navigation/DE/Themen/Material/Nanotechnologie/sichere-nanomaterialien.html) with the five sub-fields nanoCharacterisation, nanoMaterial, nanoSafety, nanoData and nanoTechnology. The link to the BAM central guidelines to the safety in technology and chemistry is given by the development of reference products such as reference measurement procedures, reference (nano)materials, and newly reference data sets. Thus, an internationally well-networked group in surface analysis has been established @BAM, with regular contributions to integral analytical characterization with metrological and standardization background.
Examples of newly developed methodical approaches will be given with an emphasis on correlative nano-analysis of morphology and chemistry of nanomaterials. Correlative imaging by STEM-in-SEM with high-resolution SEM and EDX, and further with AFM or the new technique TKD (Transmission Kikuchi Diffraction) will be explained on various examples of nanostructures, both as starting materials and embedded/functionalized nanoparticles in products. The unique analytical benefits of the Auger electron probe as a veritable nano-tool for surface chemistry will be highlighted. The panoply of advanced surface characterization methods @BAM is completed by discussing examples of hybrid analysis of the bulk of nanomaterials by X-ray Spectroscopy with the highest surface-sensitive methods X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). Particularly for the analysis of the surface chemistry of nanostructures, such as the completeness of the shells of core-shell nanoparticles or in-depth and lateral gradients of chemistry within mesoporous thin layers, the latter methods are inherent.
Other special developments like approaches for the quantitative determination of the roughness of particle surface by electron microscopy or for the quantitative determination of the porosity of thin mesoporous layers by electron probe microanalysis (EPMA) with SEM will be presented.
T2 - Seminar of the Academic Centre for Materials and Nanotechnology
CY - Online meeting
DA - 12.05.2022
KW - Nanoparticles
KW - Thin films
KW - Nano Characterisation
KW - Nanomaterials
KW - Surface morphology
KW - Surface chemistry
PY - 2022
UR - https://www.agh.edu.pl/en/info/article/seminar-advanced-characterization-of-the-surface-morphology-and-chemistry-within-nanobam/
AN - OPUS4-54820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
A1 - Hodoroaba, Vasile-Dan
T1 - Wire-Print as a Novel Sample Preparation Approach for Accurate Morphological Characterization of Constituent Particles of Graphene-Related 2D-Materials
N2 - Graphene and graphene-oxide (GO) are used for instance in catalysis, biomedical applications, in inks and as composite materials. To ensure product quality and safe-by-design principles within the various application fields, the commercial material must be characterized and specified through well-known and standardized procedures. The accurate morphological characterization of 2D materials is a challenging task, requiring careful sample preparation on a substrate either as a powder or from liquid suspension. These must be isolated, homogeneously distributed, with good statistics of the counted particles. Various sample preparation approaches have been reported in the literature, e.g. electrospray, substrate surface treatment, embedding the particulate material and polishing the cross-section, or addition of ligands to the suspended nanostructures. In this study, a novel deposition procedure for graphene-related 2D materials (GR2Ms) was systematically tested for its efficacy. The quantitative analysis of the size and shape distribution of the materials was conducted using electron microscopy and was successfully tested in XPS and EDS experiments. The technique is an extension of the conventional drop-casting method and has been designated "wire-print" deposition.
The result of such a wire-print deposition for a graphene-based suspension is shown in Figure, where various treatment conditions have been tested with a repetition of up to 10 times per condition, all together 86 spots on a silicon wafer of 10 mm².
T2 - Graphene Week 2025
CY - Vicenza, Italy
DA - 22.09.2025
KW - Graphene-related 2D materials (GR2M)
KW - Sample peparation
KW - Imaging
KW - Electron Microscopy
KW - Wire-print deposition method
PY - 2025
AN - OPUS4-64248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Evans, Alexander
A1 - Mishurova, Tatiana
A1 - Ulbricht, Alexander
A1 - Sprengel, Maximilian
A1 - Serrano-Munoz, Itziar
A1 - Fritsch, Tobias
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
A1 - Bruno, Giovanni
T1 - Diffraction-Based Residual Stress Characterization in Laser Additive Manufacturing of Metals
N2 - Laser-based additive manufacturing methods allow the production of complex metal structures within a single manufacturing step. However, the localized heat input and the layer-wise manufacturing manner give rise to large thermal gradients. Therefore, large internal stress (IS) during the process (and consequently residual stress (RS) at the end of production) is generated within the parts. This IS or RS can either lead to distortion or cracking during fabrication or in-service part failure, respectively. With this in view, the knowledge on the magnitude and spatial distribution of RS is important to develop strategies for its mitigation. Specifically, diffraction-based methods allow the spatial resolved determination of RS in a non-destructive fashion. In this review, common diffraction-based methods to determine RS in laser-based additive manufactured parts are presented. In fact, the unique microstructures and textures associated to laser-based additive manufacturing processes pose metrological challenges. Based on the literature review, it is recommended to (a) use mechanically relaxed samples measured in several orientations as appropriate strain-free lattice spacing, instead of powder, (b) consider that an appropriate grain-interaction model to calculate diffraction-elastic constants is both material- and texture-dependent and may differ from the conventionally manufactured variant. Further metrological challenges are critically reviewed and future demands in this research field are discussed.
KW - Laser-based additive manufacturing
KW - Residual stress analysis
KW - X-ray and neutron diffraction
KW - Diffraction-elastic constants
KW - Strain-free lattice spacing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538054
DO - https://doi.org/10.3390/met11111830
VL - 11
IS - 11
SP - 1830
PB - MPDI
CY - Basel
AN - OPUS4-53805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Mieller, Björn
A1 - Moos, R.
A1 - Rabe, Torsten
T1 - Lowering the sintering temperature of calcium manganate for thermoelectric applications
N2 - This study combines three different approaches to lower the sintering temperature of Sm-doped CaMnO3 to save energy in production and facilitate co-firing with other low-firing oxides or metallization. The surface energy of the powder was increased by fine milling, sintering kinetics were enhanced by additives, and uniaxial pressure during sintering was applied. The shrinkage, density, microstructure, and thermoelectric properties were evaluated. Compared to micro-sized powder, the use of finely ground powder allows us to lower the sintering temperature by 150 K without reduction of the power factor. By screening the effect of various common additives on linear shrinkage of CaMnO3 after sintering at 1100 ○C for 2 h, CuO is identified as the most effective additive. Densification at sintering temperatures below 1000 ○C can be significantly increased by pressure-assisted sintering. The power factor at room temperature of CaMnO3 nano-powder sintered at 1250 ○C was 445 μW/(m K2). Sintering at 1100 ○C reduced the power factor to 130 μW/(m K2) for CaMnO3 nano-powder, while addition of 4 wt.% CuO to the same powder led to ∼290 μW/(m K2). The combination of fine milling, CuO addition, and pressureassisted sintering at 950 ○C resulted in a power factor of ∼130 μW/(m K2). These results show that nano-sized powder and CuO addition are successful and recommendable strategies to produce CaMnO3 with competitive properties at significantly reduced temperatures and dwell times.
KW - Sintering additive
KW - Liquid phase sintering
KW - Pressure assisted sintering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555467
DO - https://doi.org/10.1063/5.0098015
SN - 2158-3226
VL - 12
IS - 8
SP - 1
EP - 9
PB - American Institute of Physics (AIP)
CY - New York, NY
AN - OPUS4-55546
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
A1 - Maierhofer, Christiane
T1 - Advanced Characterization and On-Line Process Monitoring of Additively Manufactured Materials and Components
N2 - Additive manufacturing (AM) techniques have risen to prominence in many industrial sectors. This rapid success of AM is due to the freeform design, which offers enormous possibilities to the engineer, and to the reduction of waste material, which has both environmental and economic advantages. Even safety-critical parts are now being produced using AM. This enthusiastic penetration of AM in our daily life is not yet paralleled by a thorough characterization and understanding of the microstructure of materials and of the internal stresses of parts. The same holds for the understanding of the formation of defects during manufacturing. While simulation efforts are sprouting and some experimental techniques for on-line monitoring are available, still little is known about the propagation of defects throughout the life of a component (from powder to operando/service conditions). This Issue was aimed at collecting contributions about the advanced characterization of AM materials and components (especially at large-scale experimental facilities such as Synchrotron and Neutron sources), as well as efforts to liaise on-line process monitoring to the final product, and even to the component during operation. The goal was to give an overview of advances in the understanding of the impacts of microstructure and defects on component performance and life at several length scales of both defects and parts.
KW - Non-destructive Testing
KW - Additive Manufacturing
KW - Materials Characterization
KW - Online Monitoring
KW - Residual Stress
KW - Thermography
KW - Computed Tomography
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556833
DO - https://doi.org/10.3390/met12091498
VL - 12
IS - 9
SP - 1
EP - 3
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-55683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Charmi, Amir
T1 - A multiscale numerical framework for the simulation of anistropic material response of additively manufactured stainless steel 316L undergoing large plastic deformation
N2 - Additive manufacturing (AM) offers significantly greater freedom of design compared to conventional manufacturing processes since the final parts are built layer by layer. This enables metal AM, also known as metal 3D printing, to be utilized for improving efficiency and functionality, for the production of parts with very complex geometries, and rapid prototyping. However, despite many technological advancements made in recent years, several challenges hinder the mass adoption of metal AM. One of these challenges is mechanical anisotropy which describes the dependency of material properties on the material orientation. Therefore, in this work, stainless steel 316L parts produced by laser-based powder bed fusion are used to isolate and understand the root cause of anisotropy in AM parts. Furthermore, an efficient and accurate multiscale numerical framework is presented for predicting the deformation behavior of actual AM parts on the macroscale undergoing large plastic deformations. Finally, a novel constitutive model for the plastic spin is formulated to capture the influence of the microstructure evolution on the material behavior on the macroscale.
KW - Additive Fertigung
KW - Austenitischer Stahl
KW - Finite-Elemente-Methode
KW - Mehrskalenmodell
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20240207-173356-002
DO - https://doi.org/10.25643/dbt.59550
SP - 1
EP - 163
PB - Bauhaus-Universität Weimar
CY - Weimar
AN - OPUS4-59511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Stargardt, Patrick
A1 - Moos, Ralf
A1 - Mieller, Björn
T1 - Co‐Fired Multilayer Thermoelectric Generators Based on Textured Calcium Cobaltite
N2 - Thermoelectric generators are very attractive devices for waste heat energy harvesting as they transform a temperature difference into electrical power. However, commercially available generators show poor power density and limited operation temperatures. Research focuses on high‐temperature materials and innovative generator designs. Finding the optimal design for a given material system is challenging. Here, a theoretical framework is provided that allows appropriate generator design selection based on the particular material properties. For high‐temperature thermoelectric oxides, it can be clearly deduced that unileg multilayer generators have the highest potential for effective energy harvesting. Based on these considerations, prototype unileg multilayer generators from the currently best thermoelectric oxide Ca3Co4O9 are manufactured for the first time by industrially established ceramic multilayer technology. These generators exhibit a power density of 2.2 mW/cm² at a temperature difference of 260 K, matching simulated values and confirming the suitability of the technology. Further design improvements increase the power density by a factor of 22 to facilitate practicable power output at temperature differences as low as 7 K. This work demonstrates that reasonable energy harvesting at elevated temperatures is possible with oxide materials and appropriate multilayer design.
KW - Optical and Magnetic Materials
KW - Electronic
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596306
DO - https://doi.org/10.1002/aelm.202300636
SN - 2199-160X
VL - 10
IS - 3
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-59630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fardan, Ahmed
A1 - Fazi, Andrea
A1 - Peng, Ru Lin
A1 - Mishurova, Tatiana
A1 - Thuvander, Mattias
A1 - Bruno, Giovanni
A1 - Brodin, Håkan
A1 - Hryha, Eduard
T1 - Fine-Tuning Melt Pools and Microstructures: Taming Cracks in Powder Bed Fusion—Laser Beam of a non-weldable Ni-base Superalloy
N2 - Powder Bed Fusion – Laser Beam (PBF-LB) of high γ’ strengthened Ni-base superalloys, such as CM247LC, is of great interest for high temperature applications in gas turbines. However, PBF-LB of CM247LC is challenging due to the high cracking susceptibility during PBF-LB processing (solidification cracking) and heat treatment (strain age cracking, mostly caused by residual stresses). This study focuses on understanding the impact of process parameters on microstructure, residual stresses and solidification cracking. Laser power (P), speed (v) and hatch spacing (h) were varied while the layer thickness (t) was fixed. The melt pool size and shape were found to be key factors in minimizing solidification cracking. Narrower and shallower melt pools, achieved using a low line energy density (LED = P/v ≤ 0.1 J/mm), gave low crack densities (0.7 mm/mm2). A tight hatch spacing (h = 0.03 mm) resulted in reduced lack of fusion porosity. Electron backscatter diffraction investigations revealed that parameters giving finer microstructure with 〈100〉crystallographic texture had low crack densities provided they were processed with a low LED. Atom probe tomography elucidated early stages of spinodal decomposition in the as-built condition, where Cr and Al cluster separately. The extent of spinodal decomposition was found to be affected by the LED and the hatch spacing. Samples with low LED and small hatch spacing showed higher degrees of spinodal decomposition. X-ray diffraction residual stress investigations revealed that the residual stress is proportional to the volumetric energy density (VED = P/(v. h. t)). Although low residual stresses can be achieved by using low VED, there is a high risk of lack of fusion. Hence, other parameters such as modified scan strategy, build plate pre-heating and pulsed laser mode, must be further explored to minimize the residual stresses to reduce the strain age cracking susceptibility.
KW - Additive manufacturing
KW - X-ray CT
KW - Non-weldable superalloy
KW - Solidification cracking
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597340
DO - https://doi.org/10.1016/j.mtla.2024.102059
SN - 2589-1529
VL - 34
IS - 102059
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-59734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Mishurova, Tatiana
A1 - Evans, Alexander
A1 - Fitch, Andrew N.
A1 - Haubrich, Jan
A1 - Requena, Guillermo
A1 - Bruno, Giovanni
A1 - Serrano-Munoz, Itziar
T1 - Evolution of interphase stress over a crack propagation plane as a function of stress relief heat treatments in a PBF‐LB/M AlSi10Mg alloy
N2 - AbstractIn this study, we compare the residual stress state in a laser powder bed fusion (PBF‐LB/M) AlSi10Mg alloy in the as‐built (AB) condition with that after two different heat treatments (265 °C for 1 h, HT1; and 300 °C for 2 h, HT2). The bulk residual stress (RS) is determined using synchrotron X‐ray diffraction (SXRD), and near‐surface profiles are determined using laboratory energy‐dispersive X‐ray diffraction (EDXRD). The EDXRD results do not reveal any notable difference between the conditions at a depth of 350 μm, suggesting that the machining process yields a comparable residual stress state in the near‐surface regions. On the other hand, the SXRD results show that HT1 is more effective in relieving the bulk RS. It is observed that HT1 reduces the RS state in both the aluminium matrix and the silicon network. In addtion, HT2 does not have a significant impact on relaxing the RS as‐built state of the matrix, although it does induce a reduction in the RS magnitudes of the Si phase. It is concluded that the heat treatment stress relieving is effective as long as the Si‐network is not disaggregated.
KW - Interphase residual stress
KW - Laboratory energy-dispersive X-ray diffraction (EDXRD)
KW - PBFLB/M AlSi10Mg alloy
KW - Stress-relief heat-treatments
KW - Synchrotron X-ray diffraction (SXRD)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597591
DO - https://doi.org/10.1111/str.12475
VL - 60
IS - 6
SP - 1
EP - 13
PB - John Wiley & Sons Ltd.
AN - OPUS4-59759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cabo Rios, Alberto
A1 - Mishurova, Tatiana
A1 - Cordova, Laura
A1 - Persson, Mats
A1 - Bruno, Giovanni
A1 - Olevsky, Eugene
A1 - Hryha, Eduard
T1 - Ex-situ characterization and simulation of density fluctuations evolution during sintering of binder jetted 316L
N2 - Efficient density evolution during sintering of the as-printed component is vital to reach full densification and required properties of binder jet (BJT) components. However, due to the high porosity and brittle nature of the green compact, analysis of the microstructure development during sintering is very difficult, resulting in lack of understanding of the densification process. Density development from green state (57 ± 1.6 %) up to full density (99 ± 0.3 %) was characterized by high-resolution synchrotron X-Ray computed tomography (SXCT) on BJT 316L samples from ex-situ interrupted sintering tests. Periodicity of density fluctuations along the building direction was revealed for the first time and was related to the layer thickness of ~ 42 μm during printing that decreased down to ~ 33 μm during sintering. Sintering simulations, utilizing a continuum sintering model developed for BJT, allowed to replicate the density evolution during sintering with a mean error of 2 % and its fluctuation evolution from green (1.66 %) to sintered (0.56 %) state. Additionally, simulation of extreme particle size segregation (1 μm to 130 μm) suggested that non-optimized printing could lead to undesirable density fluctuation amplitude rapid increase (~10 %) during sintering. This might trigger the nucleation of defects (e.g., layer delamination, cracking, or excessive residual porosity) during the sintering process.
KW - Additive manufacturing
KW - Synchrotron X-ray CT
KW - Binder Jetting
KW - Sintering
KW - FEM Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594389
DO - https://doi.org/10.1016/j.matdes.2024.112690
SN - 0264-1275
VL - 238
SP - 1
EP - 18
PB - Elsevier
AN - OPUS4-59438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - Towards the optimization of post laser powder bed fusion stress relieve treatments of stainless steel 316L
N2 - The formation of high magnitude residual stresses is inherent in laser powder bed fused processed austenitic steel 316L. Post-process heat treatments to relieve these stresses are necessary. In this study, heat treatment temperatures of 450°C, 800°C and 900°C were applied in order to avoid excessive sensitization. This temperature range thereby encompassed the upper and lower bounds for stress relieving treatment of this material. The residual stresses were determined by neutron diffraction and the evolution of the microstructure was monitored using scanning electron microscopy and electron backscattered diffraction. The results show that a full relaxation of the residual stresses is achieved when applying 900°C for 1 hour, which seems to be closely related to the dissolution of the subgrain solidification cellular structure.
T2 - 2nd Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online meeting
DA - 19.04.2021
KW - Residual Stress
KW - Additive Manufacturing
KW - Steel
PY - 2021
AN - OPUS4-52709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
T1 - Charakterisierung der Porositäts- und Rissdichteentwicklung in Wärmedämmschichten von Gasturbinenschaufeln mittels Synchrotron Refraktions Radiographie
N2 - Die Degradation von Wärmedämmschichten(thermal barrier coatings - TBCs) in Gasturbinen durch glasartige Calcium-Magnesium-Aluminiumsilikat (CMAS)Ablagerungen aus verschiedenen Quellen istseit vielen Jahren ein anhaltendes Problem. In dieser Studie wurde mit Hilfe derSynchrotron-Röntgen-Refraktions-Radiographie (SXRR), und vergleichend mit der Elektronenmikroskopie, das Eindringen von CMAS in die poröse Struktur von atmosphärisch plasmagespritzten (APS)TBCs sowie die Bildung und das Wachstum von Rissen unter thermisch zyklischer Belastung untersucht. Die Ergebnisse deuten darauf hin, dass die Infiltration sowie deren Kinetik im Brenner-Teststand wesentlich vom Benetzungsverhalten des CMAS beeinflusst werden. Trotz desoffensichtlichen Angriffs von CMAS auf die Korngrenzen hat die Wechselwirkung von Yttriumdioxid-stabilisiertem Zirkoniumdioxid (YSZ) mit intrudiertem CMAS keinen unmittelbaren Einfluss auf die Struktur und Dichte der innen Oberflächen(Risse, Poren). In einem späteren Stadium wird die Bildung von Rissen senkrecht zur äußeren Oberfläche in einer breiteren Zone der TBC-Schicht beobachtet.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Thermal barrier coatings
KW - TBC
KW - SXRR - Synchrotron X-ray Refraction Radiography
KW - CMAS - Calcium-Magnesium-Aluminiumsilikat
PY - 2021
UR - https://jahrestagung.dgzfp.de/Programm#P32
AN - OPUS4-52665
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
T1 - Bestimmung der Mikrostruktur und Simulation des Schädigungsverhaltens von lasergesintertem Polyamid 12 unter quasistatischer Zugbelastung
N2 - Um das Material- und Schädigungsverhalten von additiv gefertigtem Polyamid 12 (PA12) unter quasistatischer Belastung zu charakterisieren, wurden mechanische Tests und Röntgenverfahren zur Bestimmung der Mikrostruktur eingesetzt. Die Proben wurden nach dem Prinzip des Selektiven Lasersinterns (SLS) hergestellt. Unter quasistatischer Belastung mit Haltezeiten ergab sich ein visko¬plastisches Materialverhalten. Im Zugversuch wurde eine maximale Zugfestigkeit von 40.6 MPa und eine Bruchdehnung von 7.4% beobachtet. Mittels Röntgenrefraktion wurde eine Erhöhung von inneren Oberflächen beobachtet, die senkrecht zur Zugrichtung orientiert sind. Die Analyse der Gesamtporosität aus Computertomographie-Messungen ergab keine Änderung infolge der Zugbelastung. Jedoch wurde eine bimodale Porengrößenverteilung und eine steigende Sphärizität festgestellt. Das Materialverhalten wurde mit dem Chaboche-Modell simuliert und ergab eine sehr gute Übereinstimmung mit den experimentellen Ergebnissen. Allerdings gestattet dieses Modell nicht, das Schädigungsverhalten abzubilden. Daher wurde zur Simulation des Schädigungsverhaltens das Modell gemäß dem Ansatz von Gurson, Tvergaard und Needleman unter Berücksichtigung der mikrostrukturellen Parameter erweitert. Der Schwerpunkt des Beitrags liegt auf den Röntgenverfahren zur experimentellen Bestimmung der Mikrostruktur.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Additive Fertigung (AM)
KW - Polyamid 12
KW - Röntgenrefraktion
KW - Computertomographie
KW - Numerische Simulation
PY - 2021
UR - https://jahrestagung.dgzfp.de/Programm#P16
AN - OPUS4-52681
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
T1 - Tailoring the spring constant of ceramic helical compression springs
N2 - Ceramic springs combine attractive properties for applications in machinery, metrology, and sensor technology. They are electrically insulating, non-magnetic, provide a linear stress-strain behavior, and are stable at high temperatures and in corrosive environments. Generally, the precise dimensioning of a ceramic spring with respect to the spring constant is challenging. Different models are described, but many of these calculations do not match the actual spring properties. We demonstrate a reliable approach for the dimensioning and manufacturing of helical compression springs with a rectangular winding cross-section. Based on the German standard DIN 2090, which is referring to metallic springs, the spring constant can be calculated based on shear modulus, diameter, height, widths, and number of windings. Different ceramic springs were produced by milling of sintered hollow cylinders of zirconia, alumina and silicon nitride. The experimental spring constants are in very good agreement with the calculated values. Spring constants of zirconia springs were varied over three orders of magnitude between 0.02 N/mm and 5 N/mm by purposeful adaption of the spring geometry. The combination of dimensioning based on DIN 2090 and precise hard machining offers a reliable technology for the fabrication of tailored ceramic springs for special applications.
T2 - 45th International Conference and Exhibition on Advanced Ceramics and Composites (ICACC 2021)
CY - Online meeting
DA - 08.02.2021
KW - Ceramics
KW - Hard machining
KW - Spring constant
PY - 2021
AN - OPUS4-52136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Griesche, Axel
A1 - Mente, Tobias
A1 - Markötter, Henning
A1 - Al-Falahat, M.
A1 - Kardjilov, N.
T1 - Neutron Bragg edge imaging for in situ mapping of crystallographic phase-transformations and of temperature distributions during GTAW of supermartensitic stainless steel
N2 - In Neutron-Bragg-Edge Imaging (NBEI) experiments, we studied the phase transition during butt-welding of supermartensitic steel plates. Gas tungsten arc welding (GTAW) was used with a motorized torch allowing for automated weldments. The austenitization in the heat affected zone (HAZ) underneath the welding head could be clearly visualized at λ = 0.39 nm, a wavelength smaller than the Bragg edge wavelengths of both austenite and martensite. Also, the re-transformation into the martensitic phase upon cooling was detected. However, we observed an unexpected additional change in transmission at λ = 0.44 nm that is a wavelength larger than the wavelength of the Bragg edges of both the martensitic and austenitic phases. We attribute this change to the Deybe-Waller-Factor that describes the temperature dependence of coherent scattering at a crystal lattice. The observed two-dimensional attenuation map corresponds well with a temperature distribution modelling by software macros in ANSYS. Here, the absolute temperature values could be achieved by calibrating the modelled attenuation with help of a thermocouple placed at the steel plate. This allows in return for a direct two-dimensional temperature reading based on the Debye-Waller-relation between neutron attenuation and sample temperature.
T2 - ITMNR-9
CY - Buenos Aires, Argentina
DA - 12.10.2022
KW - Debye-Waller-Faktor
PY - 2023
AN - OPUS4-58627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voloskov, B.
A1 - Mishurova, Tatiana
A1 - Evlashin, S.
A1 - Akhatov, I.
A1 - Bruno, Giovanni
A1 - Sergeichev, I.
T1 - Artificial Defects in 316L Stainless Steel Produced by Laser Powder Bed Fusion: Printability, Microstructure, and Effects on the Very-High-Cycle Fatigue Behavior
N2 - The printability of artificial defects inside the additively manufactured laser powder bed fusion (LPBF) 316L stainless steel is investigated. The printing parameters of the LPBF process are optimized to produce artificial defects with reproducible sizes at desired positions while minimizing redundant porosity. The smallest obtained artificial defect is 90 μm in diameter. The accuracy of the geometry of the printed defect depends on both the height and the diameter in the input model. The effect of artificial defects on the very-high-cycle fatigue (VHCF) behavior of LPBF 316L stainless steel is also studied. The specimens printed with artificial defects in the center are tested under VHCF using an ultrasonic machine. Crack initiation is accompanied by the formation of a fine granular area (FGA), typical of VHCF. Despite the presence of relatively large artificial defects, FGA formation is observed around accidental natural printing defects closer to the surface, which can still be considered as internal. The causes for this occurrence are discussed.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - X-ray computed tomography
KW - VHCF
PY - 2022
DO - https://doi.org/10.1002/adem.202200831
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-56109
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stargardt, Patrick
T1 - Bulk vs thermal sprayed alumina for insulation applications: A comparison of electrical and dielectrical properties
N2 - Additive manufacturing (AM) processes are opening new design possibilities for large scale electrical devices such as power generators. Conventional manufacturing methods use copper rods which are wrapped, vacuum impregnated, bend and welded. These processes are labor-intensive and time-consuming. The introduction of AM methods for manufacturing the copper conductor and electrical insulation can reduce the size of the generator head, the most complex part of the generator.
In this study, the electrical and dielectrical properties of additively deposited ceramic layers are investigated and compared with the properties of conventionally fabricated bulk ceramics. The ceramic layers are thermally deposited by atmospheric plasma spraying of a commercially available alumina powder. Bulk ceramics are fabricated by dry pressing and sintering of the same powder. Microstructure and porosity were analyzed by scanning electron microscopy (SEM). Electrical and dielectrical properties such as DC resistance, dielectric strength, dielectric loss, and relative permittivity were determined according to the standards.
The microstructures of sprayed and sintered alumina show significant differences with respect to grain form and porosity. The density of the bulk ceramic is lower than the density of the sprayed layer due to the coarse particle size (d50 = 33 μm). Therefore, data from dense samples of the same chemical composition but lower particle size alumina powder were used for comparison.
T2 - Keramik 2022
CY - Online meeting
DA - 07.03.2022
KW - High Voltage Insulation
KW - Thermal Spray
KW - Dielectric Spectroscopy
KW - Atmospheric Plasma Spraying
PY - 2022
AN - OPUS4-54446
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Laser Powder Bed Fusion: Fundamentals of Diffraction-Based Residual Stress Determination
N2 - The general term additive manufacturing (AM) encompasses processes that enable the production of parts in a single manufacturing step. Among these, laser powder bed fusion (PBF-LB) is one of the most commonly used to produce metal components. In essence, a laser locally melts powder particles in a powder bed layer-by-layer to incrementally build a part. As a result, this process offers immense manufacturing flexibility and superior geometric design capabilities compared to conventional processes. However, these advantages come at a cost: the localized processing inevitably induces large thermal gradients, resulting in the formation of large thermal stress during manufacturing. In the best case, residual stress remains in the final parts produced as a footprint of this thermal stress. Since residual stress is well known to exacerbate the structural integrity of components, their assessment is important in two respects. First, to optimize process parameter to minimize residual stress magnitudes. Second, to study their effect on the structural integrity of components (e.g., validation of numerical models). Therefore, a reliable experimental assessment of residual stress is an important factor for the successful application of PBF-LB. In this context, diffraction-based techniques allow the non-destructive characterization of the residual stress. In essence, lattice strain is calculated from interplanar distances by application of Braggs law. From the known lattice strain, macroscopic stress can be determined using Hooke’s law. To allow the accurate assessment of the residual stress distribution by such methods, a couple of challenges in regard of the characteristic PBF-LB microstructures need to be overcome.
This presentation highlights some of the challenges regarding the accurate assessment of residual stress in PBF-LB on the example of the Nickel-based alloy Inconel 718. The most significant influencing factors are the use of the correct diffraction elastic constants, the choice of the stress-free reference, and the consideration of the crystallographic texture. Further, it is shown that laboratory X-ray diffraction methods characterizing residual stress at the surface are biased by the inherent surface roughness. Overall, the impact of the characteristic microstructure is most significant for the selection of the correct diffraction elastic constants. In view of the localized melting and solidification, no significant gradients of the stress-free reference are observed, even though the cell-like solidification sub-structure is known to be heterogeneous on the micro-scale.
T2 - 4th Symposium on Materials and Additive Manufacturing
CY - Berlin, Germany
DA - 12.06.2024
KW - Additive Manufacturing
KW - Residual Stress
KW - Electron Backscatter Diffraction
KW - Laser Powder Bed Fusion
PY - 2024
AN - OPUS4-60294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Pfretzschner, Beate
A1 - Kromm, Arne
A1 - Nadammal, Naresh
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Neuwirth, T.
A1 - Schulz, M.
A1 - Griesche, Axel
T1 - High-resolution Bragg-edge neutron radiography detects grain morphology in PBF-LB/M IN718
N2 - One of the main advantages of metal additive manufacturing (MAM) techniques is their ability to produce components with site-specific microstructural features. Nevertheless, microstructural defects and lack of repeatability are still major concerns in MAM. In this study, a laser powder bed fusion (PBF-LB/M) IN718 material, produced using two different scan length vectors, is investigated using Bragg-edge neutron 2D imaging (BENI) combined with electron backscatter diffraction (EBSD) analysis. BENI is able to detect, on a macroscopic scale, process-induced changes in texture in a large field of view covering the entire sample (20×80 mm2). In addition, high-resolution BENI (HR-BENI), with a pixel size of 12.8 µm, provides a micro-scale examination of the local variations of texture and grain morphology, otherwise undistinguishable using the standard resolution. As such, HR-BENI offers a straightforward and detailed way of screening the integrity of MAM parts at cm-length scales.
KW - Bragg-edge neutron 2D imaging (BENI)
KW - Metal additive manufacturing (MAM)
KW - IN718 PBF-LB/M
KW - Crystallographic texture control
KW - Electron backscatter diffraction (EBSD)
PY - 2023
DO - https://doi.org/10.1016/j.mtla.2023.101827
SN - 2589-1529
VL - 30
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-57819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Eigenspannungsrelaxation in additiv gefertigem austenitischem Stahl 316L: Einsatz moderner Beugungsmethoden
N2 - In Hinblick auf den austenitischen Stahl AISI 316L erzeugt das pulverbettbasierte selektive Laserstrahlschmelzen, als ein additives Fertigungsverfahren, kristallographisch texturierte und Multiskalige Mikrostruktur. Einerseits können diese Mikrostrukturen zu einer Verbesserung der statischen mechanischen Eigenschaften führen (z. B. zu einer höheren Streckgrenze). Andererseits stehen diesen Verbesserungen der mechanischen Eigenschaften hohe Eigenspannungen gegenüber, die sich nachteilig auf das Ermüdungsverhalten auswirken können. Zur Reduzierung der Eigenspannungen und der daraus resultierenden negativen Auswirkungen auf die Ermüdungseigenschaften, werden Bauteile nach der Herstellung typischerweise wärmebehandelt. In dieser Studie wurde eine niedrige Wärmebehandlungstemperatur von 450°C höher temperierten Behandlungen bei 800 °C und 900 °C gegenübergestellt. Diese Wärmebehandlungstemperaturen bilden die oberen und die untere Grenze ein Spannungsarmglühendes Materials, ohne die prozessinduzierte Mikrostruktur signifikant zu verändern. Zusätzlich bieten diese Temperaturen den Vorteil, dass sie eine übermäßige intergranulare Ausscheidung von Karbiden und TCP-Phasen vermeiden, die zu einer Sensibilisierung des Werkstoffes gegen korrosive Umgebungen führen würden. Die Auswirkungen der Wärmebehandlung auf das Gefüge wurden mittels Rasterelektronenmikroskopie (BSE und EBSD) untersucht. Die Relaxation der Eigenspannungen wurde vor und nach den jeweiligen Wärmebehandlungen bei 800°C und 900°C mittels Neutronenbeugung charakterisiert. Die Ergebnisse zeigen, dass die Proben nach der Wärmebehandlung bei 900 °C nahezu spannungsfrei sind, was mit der Auflösung der zellularen Substruktur korreliert.
T2 - AWT-Konferenz Additive Fertigung
CY - Bremen, Germany
DA - 29.06.2022
KW - Neutronbeugungsverfahren
KW - Additive Fertigung
KW - L-PBF 316L
KW - Eigenspannung
PY - 2022
AN - OPUS4-55788
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Residual Stresses in Additive Manufacturing (L-PBF)
N2 - Additive manufacturing (AM) technologies are experiencing an exceedingly rapid growth, driven by their potential through layer wise deposition for transformational improvements of engineering design, leading to efficiency and performance improvements. Laser Powder Bed Fusion (LPBF) is an Additive Manufacturing (AM) method which permits the fabrication of complex structures that cannot otherwise be produced via conventional subtractive manufacturing methods. Nevertheless, the rapid cooling rates associated with this process results in the formation of significant and complex residual stress (RS) fields. A large body of both experimental and simulation research has been dedicated in recent years to the control and mitigation of RS in AM. In order to validate simulations with the end goal of being able to model the residual stress state in AM components and to devise strategies for their reduction during manufacturing, experimental methods need to be able to accurately determine 3D residual stresses fields in complex geometries. Several destructive and non-destructive methods can be used to analyze the RS state, the choice of which depends on the geometry and the information required. Diffraction-based methods using penetrating neutron and synchrotron X-rays at large scale facilities offer the possibility to non-destructively spatially resolve both surface and bulk residual stresses in complex components and track their changes following applied thermal or mechanical loads. This presentation will overview the success stories of using large scale facilities by the BAM for the characterization of residual stresses in additively manufactured metallic alloys. In particular, the study of the influence of process parameters on the residual stress state and the relaxation of these stresses through heat treatment will be presented. However there remains challenges to overcome particularly of the hypotheses underlying the experimental determination of residual stresses, which will be discussed.
T2 - 10th International Conference on Mechanical Stress Evaluation by Neutron and Synchrotron Radiation – MECASENS 2021
CY - Prague, Czech Republic
DA - 25.11.2021
KW - Residual stress
KW - Additive manufacturing
KW - Diffraction
KW - L-PBF
KW - AGIL
PY - 2021
AN - OPUS4-54105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - The relaxation of macroscopic residual stresses in laser powder bed fused stainless steel 316L
N2 - The processing of stainless steel 316L using the additive manufacturing process Laser Powder Bed Fusion (LPBF) can widen its field of application due to a strong increase in Yield strength, without making major compromises on the ductility nor its outstanding corrosion and oxidation properties. Furthermore, improved designs that either reduce the weight or optimise the function of a part can be obtained using LPBF. These benefits are however counterbalanced by the proneness of LPBF to inducing high Residual Stresses (RS) during manufacturing. The characterisation and monitoring of these RS are of paramount importance for the wider acceptance of the LPBF process. This study focuses on the relaxation of the initial macroscopic RS present in an LPBF 316L as-built prism that undergoes various routes of manufacturing steps to achieve different specimen geometries and stress relieving treatments. The RS are determined using Angle-Dispersive (AD) and Time-of-Flight (TOF) neutron diffraction. The results reveal high tensile RS close to the surfaces and compressive RS near the centre of the as-built parts. The reduction in size and change of geometry heavily impact the stress ranges of the remaining RS, with lower stress ranges in cylindrical shaped compared to rectangular shaped specimens. Also, the application of different stress relieving heat treatments showed that heat-treating temperatures above 800 °C are necessary to obtain a strong relaxation in LPBF 316L.
T2 - The second European Conference on the Structural Integrity of Additively Manufactured Materials
CY - Online meeting
DA - 08.09.2021
KW - Residual Stress
KW - Additive Manufacturing
KW - Neutron Diffraction
PY - 2021
AN - OPUS4-53263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Bruno, Giovanni
A1 - Kachanov, M.
A1 - Sevostianov, I.
ED - Bruno, Giovanni
ED - Altenbach, H.
ED - Eremeyev, V.
ED - Müller, W.
ED - Gutkin, M.
T1 - Micromechanical Modeling of Non-linear Stress–Strain Behavior of Polycrystalline Microcracked Ceramics
N2 - We discuss the non-linear stress–strain behavior of microcracked polycrystalline ceramics under uniaxial tension and compression (displacement control).
Micromechanics explanation and modeling of its basic features, such as non-linearity and hysteresis in stress–strain curves, are developed, with stable microcrack propagation and “roughness” of intergranular cracks playing critical roles in tension and crack sliding playing a critical role in compression. Experiments involving complex loading histories are explained, and themodel is shown to reproduce the basic features of the observed stress–strain curves.
KW - Neutron Diffraction
KW - X-ray diffraction
KW - Mechanical Properties
KW - X-ray refraction radiography
KW - Microcracking
KW - Aluminum Titanate
PY - 2023
SN - 978-3-031-28743-5
DO - https://doi.org/10.1007/978-3-031-28744-2
SN - 1869-8433
SP - 1
EP - 22
PB - Springer
CY - Heidelberg
AN - OPUS4-57938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
T1 - Microstructure characterization of materials using X-ray refraction techniques
N2 - X-ray refraction is an excellent tool for the characterization of the microstructure of materials. However, there are only a few (synchrotron) laboratories in the world that use this technique for material characterisation. Therefore, the seminar will first explain the basic principles of X-ray refraction and the measurement techniques installed at the hard X-ray beamline BAMline at BESSY II (Berlin, Germany). This is followed by examples of investigations on fibre-reinforced plastic composites (CFRP) as well as ceramic (Cordierite, ZrO2-SiO2) and metallic materials (Ti-6Al-4V, Inconel). Some of the investigations were carried out both ex-situ and in-situ under mechanical and thermal load. The results are correlated with the mechanical properties of the materials.
T2 - LNLS Users Group Seminar Series
CY - Campinas, Brasil
DA - 25.10.2022
KW - X-ray refraction
KW - Analyzer-Based Imaging
KW - BAMline
PY - 2022
AN - OPUS4-56117
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Sophie
T1 - Material development for oxide multilayer generators
N2 - Thermoelectric generators can be used for energy harvesting by directly transforming a temperature gradient into a voltage. Multilayer generators based on low-temperature co-fired ceramics technology (LTCC) are an interesting alternative to conventional π-type generators. They exhibit several advantages like high filling factor, possibility of texturing, co-firing of all materials in one single-step, and reduction of production costs due to the high possible degree of automation. Pressure-assisted sintering enables the theoretical possibility of co-firing two promising oxide thermoelectric materials: Ca3Co4O9 (p-type) and CaMnO3 (n-type). Due to the large difference in sintering temperature (300 K) the process is very challenging.
In this work we show the material development of Ca3Co4O9, CaMnO3, insulation and metallization for multilayer generators co-fired under pressure at 900 °C. The materials are tailored regarding their sintering behavior, electrical performance and coefficients of thermal expansion. Different generator designs (unileg and pn-type) were fabricated and analyzed regarding crack formation, interaction layers and thermoelectric performance. Simulated stresses during cooling in the multilayers are compared with actual crack formation for different sintering conditions. This study shows that a lower pressure level and a lower level of complexity are beneficial for co-firing and performance.
T2 - 45th International Conference and Expo on Advanced Ceramics and Composites (ICACC 2021 Virtual)
CY - Online meeting
DA - 08.02.2021
KW - Thermoelectrics
KW - Multilayer
PY - 2021
AN - OPUS4-52462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - John, Sebastian
T1 - Beitrag zur Analyse des Eigenspannungsverhaltens von Composite-Hochdruckspeichern mit metallischem Liner
N2 - Bei der Auslegung von Druckbehältern kommen, auf Grund ihrer hohen spezifischen Festigkeit, vermehrt Faserverbundwerkstoffe zum Einsatz. Durch eine hohe Streuung von Material- und Produktionsparametern sowie unterschiedlichster Belastungsszenarien gestaltet sich jedoch Aussagen über die Lebensdauer sowie eine Festlegung sinnvoller Prüffristen als schwierig. Im Fokus der Untersuchungen steht ein Behälterdesign mit metallischem Liner und einem kohlenstofffaserverstärkten Kunststoffverbund, wobei die Lebensdauer maßgeblich durch den im Metall vorherrschenden Eigenspannungszustand bestimmt wird. Mit Hilfe einer alterungsbegleitenden Eigenspannungsanalyse werden Eigenspannungsveränderungen erfasst und in einem erarbeiteten Betriebsfestigkeitsmodell berücksichtigt. Durch eine Nachstellung verschiedener Belastungsszenarien kann gezeigt werden, dass durch die Berücksichtigung einer veränderlichen Eigenspannung die Anzahl ertragbarer Lastwechsel bis zum Versagen sowie damit verbundene Überlebenswahrscheinlichkeiten mit einer erhöhten Genauigkeit abgeschätzt werden können.
KW - Komposit
KW - Druckbehälter
KW - Pressure vessel
KW - Eigenspannung
KW - Residual stress
KW - Alterung
KW - Aging
KW - Faserverbund
KW - Fibre reinforced plastics
KW - Composite
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520269
SN - 978-3-7983-3180-8
SN - 978-3-7983-3179-2
DO - https://doi.org/10.14279/depositonce-10442
SN - 2512-515X
SN - 2512-5141
VL - 10
SP - 1
EP - 188
PB - Universitätsverlag der TU Berlin
CY - Berlin
AN - OPUS4-52026
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
T1 - Automated self-adjustment of array probe with a robotic ultrasonic test system
N2 - Ultrasonic testing (UT) of objects with complex geometries often requires the use of a robotic arm to position the probe perpendicular to the local surface. Using immersion makes it possible to test these objects with standard ultrasonic linear array probes. Here, the probe positions and orientations provided by the robot are used for merging the locally acquired image data into a 3D-reconstruction. The quality of this reconstruction is highly dependent on the alignment of the tool center point (TCP) of the physical probe with the TCP used in the digital model. For common industrial tools, the TCP is usually acquired using geometric features of the tools. However, for ultrasonic arrays in immersion, there is a water standoff between the probe and the test object, therefore the TCP is in free space in front of the array and cannot be acquired with the common method. To overcome this challenge, we propose a method that allows the robotic ultrasonic system to automatically self-adjust the positioning of the UT probe using a test block made of steel with defined geometric features as a target for referencing. For each of the six degrees of freedom, a scan and adjustment routine are established using the data acquired by the UT probe to update the TCP’s position and orientation in the robot control. Given a coarse pre-definition of the TCP and the known target test block, no human interaction is required while the system determines the optimum tool position and orientation. Part of this work will be used to improve and extend standards for robotic ultrasonic test systems, e.g. ISO 24647.
T2 - 20th World Conference On Non-Destructive Testing
CY - Incheon, South Korea
DA - 27.05.2024
KW - Ultrasonic
KW - Testing
KW - Automation
KW - Robotics
KW - NDT 4.0
PY - 2024
AN - OPUS4-60565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
T1 - Automatisierte Wanddickenbestimmung an Prüfteilen mit komplexen Geometrien aus anisotropen Werkstoffen
N2 - Im Rahmen des Projektes MRO2.0, das sich mit der digitalen Transformation des Servicezyklus von modernen Gasturbinenschaufeln beschäftigt, wurde gezeigt, wie sich automatisiert und flächendeckend die (Rest-)Wanddicke an variabel gekrümmten Prüfgeometrien bestimmen lässt. Es wurde ein Roboterarm verwendet, der ein lineares Ultraschallarray in Tauchtechnik führt und Prüfdaten aufnimmt, die mit einer adaptierten TFM (Total Focusing Method) zu Rekonstruktionen der Außen- und Innenoberfläche verarbeitet werden. In der aktuellen zweiten Projektphase wird die Methode für Werkstoffe erweitert, die anisotrope akustische Eigenschaften aufweisen. In diesem Beitrag wird eine Methode vorgestellt, wie sich die Kristallausrichtung bzw. die richtungsabhängige Schallgeschwindigkeit mittels eines linearen Ultraschallarrays bestimmen lässt. Für den Sendefall eines Randelements in Kontakttechnik können dabei Wellen identifiziert werden, die sich parallel zur Prüfkopfapertur im Prüfobjekt ausbreiten und mit der richtungsabhängigen Schallgeschwindigkeit skalieren. Die ermittelte Schallgeschwindigkeitsverteilung kann dann verwendet werden, um die lokale Wanddickenbestimmung für die Anisotropie zu adaptieren.
T2 - 6. Workshop Messtechnische Anwendungen von Ultraschall
CY - Drübeck, Germany
DA - 17.06.2024
KW - Ultraschallprüfung
KW - Anisotropie
KW - Turbinenschaufel
KW - NDT 4.0
PY - 2024
AN - OPUS4-60568
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Paun, I. A.
A1 - Heitz, J.
A1 - Stoian, R.
T1 - Guest editorial: Making light matter
N2 - This article represents the Guest Editorial of the Special Issue associated with the Symposium L "Making light matter: lasers in material sciences and photonics" held during the 2023 E-MRS Spring Meeting in Strasbourg, France, June 25th - July 2nd, 2023.
T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - Guest Editorial
KW - Laser
KW - Material Science
KW - Photonics
PY - 2024
DO - https://doi.org/10.1002/pssa.202400528
SN - 1862-6319
VL - 221
IS - 15
SP - 1
EP - 5
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-60948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Florian, Camilo
T1 - Optical thickness-profiling for fs-laserinduced superficial amorphization and oxide removal on silicon
N2 - Amorphization and re-crystallization of polished silicon wafers cut in <111> and <100> orientation were studied after irradiation by single Ti:sapphire femtosecond laser pulses (790 nm, 30 fs) using optical imaging, topographic characterization, and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) enabled fast data acquisition at multiple wavelengths and provided experimental data for calculating the amorphous layer thickness profiles with lateral resolution in the micrometer and vertical resolution in the nanometer range based on a thin-film layer model including the topmost native oxide. For a radially Gaussian shaped laser beam and at moderate peak laser fluences above the melting but below the ablation threshold, laterally parabolic amorphous layer profiles with maximum thicknesses of some tens of nanometers were quantitatively derived. Moreover, the threshold fluence of the native oxide removal was quantified. At laser peak fluences closely below the ablation threshold of silicon, SIE is capable to reveal even the laser-induced removal and formation of the native oxide covering the Si wafers under ambient air conditions. The accuracy of these all-optical, non-destructive SIE-based layer thickness assessments is verified experimentally through high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the oxide removal and superficial re-solidification of silicon after local melting by femtosecond laser pulses can be drawn.
T2 - E-MRS Spring Meeting 2025
CY - Strasbourg, France
DA - 26.05.2025
KW - Femtosecond laser
KW - Laser-induced amorphization
KW - Native oxide layer
KW - Spectroscopic imaging ellipsometry
KW - Transmission electron microscopy
PY - 2025
AN - OPUS4-63275
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters!
N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions.
T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13
CY - Lecce, Italy
DA - 14.09.2025
KW - Biofilm
KW - Bacterial adhesion
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
PY - 2025
AN - OPUS4-64166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaczmarek, D.
A1 - Bonse, Jörn
T1 - Capabilities and limitations of Sipe’s first principles LIPSS theory: current aspects and directions
N2 - This presentation elucidates the fundamentals and capabilities of John E. Sipe’s first principles theory (1983) of laser-induced periodic surface structures (LIPSS), representing an analytical mathematical approach (Green’s formalism) to calculate the absorption of electromagnetic radiation at a microscopically rough surface via the so-called efficacy factor. It includes a discussion of assumptions made in the theory and resulting limitations, such as the restriction to a near-surface layer (the so-called “selvedge”), the lack of any material response, or missing inter-pulse feedback phenomena being relevant in typical multi-pulse irradiation conditions. The influence of the angle of incidence, the polarization direction (s-pol. or p-pol.), the optical properties (dielectric permittivity) of the irradiated materials, as well as its surface roughness and its specific encoding in the theory via a shape factor (s) and a filling factor (f) are addressed.
A simplifying mathematical reformulation (without changing the validity range) of Sipe’s theory in the form of 14 complex-valued equations published in 2005 is motivated, as well as the necessity of some minor adjustments for non-normal incident radiation - revealed in a very recent Erratum. Starting with 2009, extensions of the original theory were developed, e.g., the analytical Sipe-Drude model in order to include intra-pulse transient changes of the optical properties of the material. Finite-difference time-domain (FDTD) numerical simulations successfully confirmed in 2012 the validity of the Sipe-Drude approach. Moreover, the FDTD formalism can be extended to sub-surface regions and can be combined with a material response (topography) modelling for iteratively considering inter-pulse feedback phenomena.
Finally, we will provide characteristic examples of Sipe’s efficacy factor for typical material classes (metals, semiconductors, dielectrics), we will explain how the results can be interpreted, and line out how the Sipe theory may be extended further.
T2 - 12th International LIPSS Workshop
CY - Leipzig, Germany
DA - 11.09.2024
KW - Laser-induced periodic surface structures (LIPSS)
KW - Theory
KW - Green's formalism
KW - Scattering waves
KW - Finite-difference time-domain calculations
PY - 2024
AN - OPUS4-61098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martínez, E.
A1 - Lejeune, N.
A1 - Frechilla, J.
A1 - Porta-Velilla, L.
A1 - Forneau, E.
A1 - Angurel, L. A.
A1 - de la Fuente, G. F.
A1 - Bonse, Jörn
A1 - Silhanek, A. V.
A1 - Badía-Majós, A.
T1 - Laser engineered architectures for magnetic flux manipulation on superconducting Nb thin films
N2 - Custom shaped magnetic flux guiding channels have been fabricated on superconducting Nb thin films by laser nanopatterning of their surface. Preferential pathways are defined by suitable combination of imprinted anisotropic pinning domains through laser-induced periodic surface structures (LIPSS). Generated by the selective energy deposition of femtosecond UV laser pulses, quasi-parallel ripple structures are formed under optimized irradiation conditions. On average, each domain is formed by grooves with a lateral period of 260–270 nm and a depth about 80 nm. By combination of scanning and transmission electron microscopy, magneto-optical imaging, and conductive atomic force microscopy techniques, we conclude that the boundaries of the LIPSS-covered domains play a prominent role in the magnetic flux diversion process within the film. This is confirmed by dedicated modeling of the flux dynamics, combined with the inversion of the magneto-optical signal. The created metasurfaces enable control of the flux penetration process at the microscale.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Magnetic flux
KW - Magneto-optical imaging (MOI)
KW - Critical current density
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611243
UR - https://www.sciencedirect.com/science/article/pii/S0169433224019287
DO - https://doi.org/10.1016/j.apsusc.2024.161214
SN - 1873-5584 (Online)
SN - 0169-4332 (Print)
VL - 679
SP - 1
EP - 12
PB - Elsevier
AN - OPUS4-61124
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wonneberger, R.
A1 - Gräf, S.
A1 - Bonse, Jörn
A1 - Wisniewski, W.
A1 - Freiberg, K.
A1 - Hafermann, M.
A1 - Ronning, C.
A1 - Müller, F. A.
A1 - Undisz, A.
T1 - Tracing the Formation of Femtosecond Laser-Induced Periodic Surface Structures (LIPSS) by Implanted Markers
N2 - The generation of laser-induced periodic surface structures (LIPSS) using femtosecond lasers facilitates the engineering of material surfaces with tailored functional properties. Numerous aspects of their complex formation process are still under debate, despite intensive theoretical and experimental research in recent decades. This particularly concerns the challenge of verifying approaches based on electromagnetic effects or hydrodynamic processes by experiment. In the present study, a marker experiment is designed to conclude on the formation of LIPSS. Well-defined concentration depth profiles of 55Mn+- and 14N+-ions were generated below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using ion implantation. Before and after LIPSS generation, marker concentration depth profiles and the sample microstructure were evaluated by using transmission electron microscopy techniques. It is shown that LIPSS predominantly formed by material removal through locally varying ablation. Local melting and resolidification with the redistribution of the material occurred to a lesser extent. The experimental design gives quantitative access to the modulation depth with a nanometer resolution and is a promising approach for broader studies of the interactions of laser beams and material surfaces. Tracing LIPSS formation enables to unambiguously identify governing aspects, consequently guiding the path to improved processing regarding reproducibility, periodicity, and alignment.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser processing
KW - Ion implantation
KW - Transmission Electron Microscopy (TEM)
KW - Stainless steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623990
DO - https://doi.org/10.1021/acsami.4c14777
SN - 1944-8244 (Print)
SN - 1944-8252 (Online)
VL - 17
IS - 1
SP - 2462
EP - 2468
PB - ACS Publications
AN - OPUS4-62399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser Nanotexturierung von Metalloberflächen zur Reduktion von Reibung und Verschleiß
N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nanostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet.
T2 - Online Abendvortrag beim AWT Härterei- und Werkstoffkreis Bodensee der Arbeitsgemeinschaft Wärmebehandlung + Werkstofftechnik e.V.
CY - Online meeting
DA - 16.01.2025
KW - Additive
KW - Laser-induzierte periodische Nanostrukturen
KW - Reibungsreduktion
KW - Verschleißreduktion
PY - 2025
AN - OPUS4-62432
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voss, Heike
T1 - Morphology and regularity of high-spatial frequency laser-induced periodic surface structures (HSFL) on titanium materials
N2 - Titanium and its alloys are known to allow the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, HSFL were processed on different titanium materials (bulk, film) upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈ 1 ps pulse duration) under different laser scan processing conditions. Here we extend our previous work on chemical analyses of HSFL on titanium materials towards a more detailed morphological and topographical surface characterization. For that, scanning electron and atomic force microscopic images are subjected to a regularity analysis using our self-developed ReguΛarity software. The regularity of the HSFL is assessed with respect to the influences of sample- and laser-related parameters, as well as the imaging method used.
T2 - 13th International LIPSS Workshop
CY - Enschede, Netherlands
DA - 29.10.2025
KW - Laser-induced periodic surface structures (LIPSS)
KW - Titanium
KW - Ultrashort laser pulses
KW - Laser processing
PY - 2025
AN - OPUS4-64631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krüger, Jörg
T1 - X-ray emission during ultrashort pulse laser material processing
N2 - The unwanted emission of X-rays during ultrashort pulse laser material processing in air was already reported more than 20 years ago for pulse repetition rates in the 1 kHz range [1]. It was stated that an enclosure of the experimental setup is necessary to protect the operator from X-rays. By now, the use of ultrashort pulse laser technology has become established in industry using repetition rates in the multi 100 kHz up to the GHz range and laser average powers up to the kW level. Since 2018/2019, more and more investigations have been carried out on the hazards from X-rays at higher laser pulse repetition rates [2-4]. Recently, maximum X-ray skin dose rates of the order of 1 Sv/h (iron target [5]) and X-ray photon energies of up to 40 keV (tungsten target [6]) were reported. Measures must be taken to shield the unwanted X-rays.
T2 - 10th Conference on Applications of Femtosecond Lasers in Materials Science (FemtoMat)
CY - Mauterndorf, Austria
DA - 24.02.2025
KW - Ultrashort pulse laser
KW - Material processing
KW - X-ray emission
KW - Radiation protection
PY - 2025
AN - OPUS4-62665
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Laser Nanotexturierung von Metalloberflächen zur Reduktion von Reibung und Verschleiß
N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nanostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet.
T2 - Internationale Bodensee Fachtagung „Wärmebehandlung und Oberflächentechnik zur Verbesserung von Tribologie und Verschleissbeständigkeit"
CY - Feldkirch, Austria
DA - 20.03.2025
KW - Additive
KW - Laser-induzierte periodische Nanostrukturen
KW - Reibungsreduktion
KW - Verschleißreduktion
PY - 2025
AN - OPUS4-62757
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Generation and characterization of anisotropic nanostructures using ultrashort pulsed lasers
N2 - The lecture gives an overview of the generation and characterization of anisotropic nanostructures using ultrashort pulsed laser radiation. Special attention will be paid to the phenomenon of so-called laser-induced periodic surface structures (LIPSS) on various materials. One focus will be on dielectrics and the dynamics of nanostructure formation. Further examples of bulk nanostructures from the literature will be discussed.
T2 - 8th UKP-Workshop: Ultrafast Laser Technology
CY - Aachen, Germany
DA - 08.04.2025
KW - Laser-induced Periodic Surface Structures (LIPSS)
KW - Dielectrics
KW - Surface Nanostructures
KW - Volume Nanostructures
PY - 2025
AN - OPUS4-62947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Bonse, Jörn
ED - Paun, I. A.
ED - Heitz, J.
ED - Stoian, R.
T1 - Special issue: Making light matter
N2 - This special issue represents the proceedings of the Symposium L "Making light matter: lasers in material sciences and photonics" held from May 29th to June 2nd 2023 in Strasbourg, France, during the 2023 Spring Meeting of the European MaterialsResearch Society (E-MRS).
T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - E-MRS Spring Meeting 2023
KW - Laser Processing
KW - Material Science
KW - Photonics
PY - 2024
UR - https://onlinelibrary.wiley.com/toc/18626319/2024/221/15
SN - 1862-6319
VL - 221
IS - 15
SP - 2300478
EP - 2400528
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-60949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Ultrafast optical probing of laser-induced formation of periodic surface nanostructures
N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a coherent laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. The presentation provides an overview of current theories on LIPSS and the quest to achieve ever smaller surface nanostructures. The historical development of the fundamental ideas behind LIPSS is presented, together with experimental approaches that make it possible to distinguish between the various LIPSS formation scenarios. Time-resolved experimental methods are required to investigate the dynamics of their formation. The presentation focuses on ultrafast time-resolved optical (pump-probe) techniques that can be used for localized point measurements or microscopic imaging, utilizing the reflection, diffraction, or coherent scattering of the probe radiation at the emerging LIPSS, while simultaneously capturing information about rapid melting, ablation, and solidification phenomena. However, given the sub-micrometric spatial periods of LIPSS, their analysis using optical radiation employed in far-field techniques remained a challenge. Therefore, short wavelengths of the probe beam in the UV range or even below are required to overcome the diffraction limit imposed in the optical spectral range. Fourth-generation light sources, namely short-wavelength (XUV or X-ray) short-pulse free-electron lasers (FELs), offer new and fascinating possibilities for resolving laser-induced structure formation on surfaces in the sub-micrometer to nanometer range and in time domains from picoseconds to several nanoseconds with a resolution in the sub-picosecond regime. On laser-irradiated semiconductor surfaces, this unique spatio-temporal resolution enables the detection of early signs of coherent/plasmonic electromagnetic scattering effects, followed by the excitation of hydrodynamic capillary waves – providing new insights into the above-mentioned debate. Recent experiments at the European XFEL used fs-time-resolved small-angle X-ray scattering (fs-SAXS) and even fs-time-resolved grazing incidence small-angle X-ray scattering (fs-GISAXS), combined with grazing-incidence diffraction (fs-GID), to reveal the dynamics of the formation of nanometric LIPSS on metals.
T2 - CINSaT Herbstkolloquium 2025
CY - Kassel, Germany
DA - 05.11.2025
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
KW - Pump-probe measurements
KW - Free-electron laser
KW - Small angle X-ray scattering (SAXS)
PY - 2025
AN - OPUS4-64633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
T1 - Robotergestützte Ultraschallprüfung von Objekten mit komplexen Geometrien
N2 - Durch den Einsatz moderner digitaler Design- und Fertigungsmethoden wachsen einerseits die Komplexität von Bauteilen, andererseits der Bedarf an Informationen über deren Qualität und Zustand. Damit steigen auch die Anforderungen an die zerstörungsfreie Prüfung, die im Zuge von ZfP 4.0 automatisierte und flexible, innovative Prüfmethoden erfordert. Das gilt insbesondere für Objekte, deren Oberflächengeometrien über plane Flächen und eindimensionale Krümmungen hinausgehen.
Um zu zeigen, wie eine Ultraschallprüfung von Objekten mit komplexer Oberflächengeometrie realisiert werden kann, wurde an der BAM eine roboterbasierte Demonstratoranlage entwickelt. Dabei führt ein Roboterarm einen Array-Prüfkopf in Tauchtechnik senkrecht über die Prüffläche. Die dafür erforderliche Prüfbahn kann entweder anhand der CAD-Geometrie oder mithilfe einer Punktewolke der Prüffläche, die vorab mit einem am Roboter angebrachten Laser-Profilometer erfasst wird, ermittelt werden. Zur Erhöhung der Genauigkeit werden der Lasersensor und der Ultraschallprüfkopf automatisiert mit dafür entwickelten Routinen am Roboter eingemessen.
Durch bildgebende Verfahren und eine automatische Auswertung der Bilder kann die in Tauchtechnik auftretende Brechung des Schallbündels an der Prüfteiloberfläche berücksichtigt werden, was die ortsrichtige Rekonstruktion von Anzeigen aus dem Prüfteilinneren bzw. der Rückwand ermöglicht. Durch Rückführung der Anzeigen in ein gemeinsames Koordinatensystem entsteht eine 3D-Rekonstruktion des Prüfteils.
Der vorliegende Beitrag stellt die Demonstratoranlage und die angewendeten Methoden im Detail vor und nennt Anwendungsbeispiele.
T2 - DGZfP Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - Ultraschall
KW - Robotik
KW - Turbinenschaufel
KW - Wanddicke
KW - Defekterkennung
PY - 2025
AN - OPUS4-63417
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voss, Heike
T1 - ReguΛarity - A free software for the objective quantification of the regularity of periodic surface structures generated by femtosecond laser irradiation
N2 - The precise laser-based surface structuring on the micro- and nanoscale allows to create functional properties for innovative applications, e.g., in medicine, optics and biology. Among the various types of surface structures, laser-induced periodic surface structures (LIPSS) are characterized by their versatility and the relatively simple manufacturing process. However, the fabrication of highly regular LIPSS patterns remains challenging. The systematic investigation of LIPSS formation, as well as of the resulting functional properties requires a precise evaluation of the surface morphology, especially with regard to periodicity and regularity. Existing quantification methods such as Fast Fourier Transformation (FFT) tend to lack automation and objectivity, especially when dealing with large data sets and multi-scale structures. Although automated approaches exist with the Gini coefficient and the P³S method, their limited availability restricts a broader scientific use. We therefore introduce ReguΛarity as an innovative open-source software solution for objective, rapid and reproducible evaluation of structured surfaces concerning their regularity. In order to provide comprehensive surface morphological analysis, our software uses advanced image-processing techniques and integrates the already developed tools such as P³S method, Gini coefficient, FFT analysis, and the calculation of DLOA (Dispersion of LIPSS Orientation Angle). The software allows to evaluate any relevant image format as provided, e.g., by standard scanning electron micrographs. An intuitive PyQt5-based interface, enhanced by multi-threading capabilities, facilitates efficient data processing. Interactive features such as region-of-interest selection and plotting provide flexible adaptation to diverse applications. ReguΛarity offers a robust analysis tool that will contribute to the further development of precise laser-based surface structuring and to the optimization of the desired functional properties in both research and industry.
T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13
CY - Lecce, Italy
DA - 14.09.2025
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser processing
KW - Fourier transformation
KW - Regularity
PY - 2025
AN - OPUS4-64176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rahner, E.
T1 - From nightmare to numbers - A novel software tool for objective regularity analysis of LIPSS
N2 - The precise laser-based surface structuring on the micro- and nanoscale allows for the creation of functional properties for innovative applications, e.g., in medicine, optics and biology. Among the various types of surface structures, laser-induced periodic surface structures (LIPSS) are distinguished by their versatility and the comparatively simple manufacturing process. Nevertheless, the fabrication of highly regular LIPSS patterns remains challenging. The systematic investigation of LIPSS formation, as well as of the resulting functional properties demands accurate and objective evaluation of surface morphology, especially regarding periodicity and regularity. Existing quantification methods such as Fast Fourier Transformation (FFT) tend to lack automation and objectivity, especially when dealing with large data sets and multi-scale structures. Although automated approaches, such as those based on the Gini coefficient or the P³S method, have been proposed, their limited availability hinders a broader scientific use. To overcome these limitations, we introduce ReguΛarity, a novel, freely available Python-based software tool featuring a graphical user interface for automated and quantitative assessment of regularity in period and (quasi-)periodic surface patterns including LIPSS. The software processes microscopic images obtained from optical, scanning electron microscopy (SEM), or atomic force microscopy (AFM), combining image segmentation with one- and two-dimensional Fourier analyses (1D-FT, 2D-FT), phase evaluation, and gradient-based orientation determination to facilitate a comprehensive regularity analysis of (quasi-)periodic surface patterns with spatial periods Λ. Regularity is quantified by the newly proposed five-dimensional regularity tuple R comprising the normalized spread of spatial periods from 2D-FT, the normalized local variation of the dominant spatial period from 1D-FT, the Gini coefficient G, the Dispersion of the LIPSS Orientation Angle (DLOA), and the mean phase deviation. The demonstration of the software’s capabilities is achieved by comparing idealized sinusoidal test patterns with SEM micrographs of fs-laser-generated LIPSS on stainless steel (AISI 316L) and aluminum alloy (AlMg5). This comparison highlights ReguΛarity’s objective differentiation between varying levels of structural regularity. The software facilitates high-throughput analysis and data-driven optimization in laser surface engineering processes.
T2 - 13th International LIPSS Workshop
CY - Enschede, Netherlands
DA - 29.10.2025
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Fourier transform
KW - Gini coefficient
PY - 2025
AN - OPUS4-65047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gräf, S.
T1 - Ion marker implantation as key to understand the formation of femtosecond LIPSS on steel
N2 - Ultrashort laser (fs-laser) pulses can be used to generate laser-induced periodic surface structures (LIPSS, ripples) on different types of materials. A variety of potential applications of these grating-like LIPSS have already been demonstrated in the field of surface functionalization. Examples include structural colours (e.g. for optical effects or safety features), beneficial friction and wear reduction, modification of the wetting behaviour of surfaces, and antibacterial or cell adhesion promoting properties for medical implants. Despite decades of research, however, some aspects regarding the formation mechanism are still unclear and the subject of controversial debate. This involves the two main models of coherent electromagnetic scattering and matter reorganization, which are used for explaining aspects of LIPSS formation and phenomenology. One major issue is to quantify the actual amount of material removal during the fs-laser processing due to the lack of an independent depth reference and to visualize the so-called heat-affected zone accompanying intense fs-laser irradiation.
In the present study, near-surface implantation of Mn and N ions into different material depth of Mn-free austenitic stainless steel alloy FeCrNiMo18-12-2 was used to create reference layers of a defined thickness containing the respective elements. LIPSS (type low-spatial frequency LIPSS, LSFL) were fabricated on the polished substrate surfaces in an air environment by fs-laser irradiation (λ = 1025 nm, τ = 300 fs, frep = 100 kHz, F = 1.5 J/cm2). The implanted layers subsequently served as a kind of coordinate system to assess the material removal during the formation process via cross-sectional Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDXS). Using both analysis methods enabled in particular to determine the position of peaks and valleys of the LIPSS topography in relation to the initial surface before fs-laser irradiation. This confirmed the selective ablation in the LIPSS valleys. Moreover, linking changes in the material’s microstructure, e.g., the crystallinity and near surface elemental composition before and after fs-laser treatment, gave additional insights regarding the transient cooling rates, as recently shown for NiTi alloys.
T2 - 13th International LIPSS Workshop
CY - Enschede, Netherlands
DA - 29.10.2015
KW - Energy dispersive X-ray analysis (EDX)
KW - Ion implantation
KW - Laser-induced periodic surface structures (LIPSS)
KW - Steel
KW - Transmission electron microscopy (TEM)
PY - 2025
AN - OPUS4-64900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters!
N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface, and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions.
T2 - 13th International LIPSS Workshop
CY - Enschede, Netherlands
DA - 29.10.2025
KW - Bacterial adhesion
KW - Biofilm
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
PY - 2025
AN - OPUS4-64632
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Voss, Heike
T1 - Morphology and regularity of high-spatial frequency laser-induced periodic surface structures (HSFL) on titanium materials
N2 - Titanium and its alloys are known to enable the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high-spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, HSFL were processed on different titanium materials (bulk, film) upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈1 ps pulse duration) under different laser scan processing conditions in normal air atmosphere. Here, we extend our previous work on chemical analyses of HSFL on titanium materials towards a more detailed large-area morphological and topographical surface characterization. For this purpose, scanning electron or atomic force microscopic images are subjected to a regularity analysis using our ReguΛarity software. The results are assessed with respect to the influences of sample- or laser-related parameters on the regularity of the HSFL.
T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13
CY - Lecce, Italy
DA - 14.09.2025
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser processing
KW - Ulltrashort laser pulses
KW - Titanium
PY - 2025
AN - OPUS4-64173
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gräf, S.
T1 - Ion marker implantation for tracing the formation of femtosecond LIPSS on steel
N2 - An ion marker experiment is conducted to investigate the formation of low spatial frequency laser-induced periodic surface structures (LIPSS) on stainless steel surfaces upon scan-processing with femtosecond laser pulses (300 fs, 1025 nm, 100 kHz) focussed to a spot diameter of ~20 µm. Defined concentration depth profiles of 14N^+- and 55Mn^+-ions were implanted below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using an acceleration energy of 380 keV. This generated two distinct “depth-tracer-layers” ~135 nm (55Mn) and ~340 nm (14N) below the sample surface. The sample morphology and microstructure were evaluated before and after LIPSS-processing using scanning and transmission electron microscopy techniques in top-view and cross-sectional geometry. Energy-dispersive X-ray spectroscopy (EDXS) allowed to visualize the depth distribution of the marker elements, the steel constituents, and of oxygen involved through the laser processing in ambient air. These experiments revealed that the LIPSS on this metal are predominantly formed by material removal through locally varying ablation and, to a lesser extent, by local melt displacement effects prior to the re-solidification. Moreover, the processing in air leads to the formation of a less than 10 nm thick laser-induced oxide layer covering the steel surface. Our new tracer ion approach contributes to the ongoing debate on the relevance of electromagnetic or hydrodynamic effects during the formation of LIPSS.
T2 - E-MRS Spring Meeting 2025
CY - Strasbourg, France
DA - 26.05.2026
KW - Laser-induced periodic surface structures (LIPSS)
KW - Steel
KW - Ion implantation
KW - Transmission electron microscopy (TEM)
KW - Energy dispersive X-ray analysis (EDX)
PY - 2025
AN - OPUS4-63274
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koch, Claudia
T1 - Ensuring Quality Smarter with a digital Quality Infrastructure (Mexican-German Technical Exchange)
N2 - The presentation introduces the initiative QI‑Digital, which aims to holistically transform quality infrastructure across all its elements. To this end, a digital QI ecosystem is being developed that integrates digital QI tools with advanced methods for testing, inspection, and monitoring, and embeds them into the broader digital industrial ecosystem.
Sovereign and secure data sharing and management are enabled through technologies such as data spaces, the Asset Administration Shell, verifiable credentials, and the Digital Product Passport (DPP). Particular emphasis is placed on the role of artificial intelligence in quality assurance: Several use cases and ongoing projects from BAM are presented togetehr with the business benefits they enable. Ongoing activities on the use of AI for manageing quality-related documentation are also presentated that aim at establishing an agentic AI framework for QI.
The talk concludes with key lessons learned so far within the initiative.
T2 - Mexican-German Technical Exchange on QI Digital
CY - Mexico City, Mexico
DA - 23.01.2026
KW - Quality infrastructure
KW - Agentic AI
KW - Digital Ecosystem
PY - 2025
AN - OPUS4-65411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mantouvalou, I.
A1 - Bauer, L.J.
A1 - Truong, V.-B.
A1 - Wagener, Y.
A1 - Förste, F.
A1 - Maruchenko, O.
A1 - Werner, S.
A1 - Lizzi, F.
A1 - Wieder, Frank
A1 - Wolff, T.
A1 - Kanngießer, B.
A1 - Zaslansky, P.
T1 - Quantitative micro-XRF combined with X-ray imaging reveals correlations between Zn concentration and dentin tubule porosity across entire teeth
N2 - Bony materials are biogenic composites of protein fibers and mineral that create hierarchical structures. In the case of teeth, dentin is the main component and similar to other bones, it contains porosity at multiple length scales. It is traversed by micron-sized hollow channels known as dentinal tubules, essential for temperature and pain sensation. Tubule density and thus porosity vary throughout the macroscopic three-dimensional (3D) structure, with porosity increasing toward the pulp. The different densities in teeth are easily revealed non-destructively in 3D by X-ray imaging using computer tomography (CT). Yet elemental composition analysis is more difficult to obtain from within the centimeter-sized heterogeneous bulk material. We describe an approach of merging CT measurements of healthy, intact bovine teeth with micro-X-ray fluorescence (micro-XRF) images of matching serially sectioned slices. Through the combination of multi-resolution quantitative CT measurements with elemental mass fraction derivation, gradients in density and element distributions such as calcium (Ca), phosphorus (P), and zinc (Zn) are revealed across entire teeth in 3D. While the main constituents (Ca and P) are homogeneously distributed in the matrix, Zn concentration increases significantly and exponentially toward the pulp. We find an inverse association between dentin tissue density and Zn concentration localizing this element in or around tubules. Our data serve as a quantitative reference for density and Zn mass fractions in healthy, neither carious nor hypermineralized dentin, as a basis for comparisons across species in health and disease states.
KW - Dentin density
KW - Micro-computer tomography
KW - Quantitative micro-X-ray fluorescence
KW - Tubule porosity
KW - Zn distribution
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654215
DO - https://doi.org/10.1002/VIW.20250173
SN - 2688-3988
SN - 2688-268X
SP - 1
EP - 14
PB - Wiley Online Library
AN - OPUS4-65421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - MINERVA-OS: The Orchestrator of our SDL for Nano and Advanced Materials Synthesis
N2 - We present our SDL "Minerva" and its' Orchestrator "Minerva-OS". We discuss the general architecture of the orchestrator, the problems our orchestration solution solves, associated objectives, and success criteria. We demonstrate how a user would interact with it and give examples of what it has already been used for. We also provide some explanation of the available and planned features, and how workflows/experiments are represented. Lastly, we discuss key technical challenges we faced during development.
T2 - Orchestration Alignment Virtual Workshop
CY - Online meeting
DA - 20.01.2026
KW - Self Driving Labs
KW - Materials Acceleration Platforms
KW - Workflows
KW - Orchestration
PY - 2026
AN - OPUS4-65422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Genga, R. M.
T1 - Enhanced Fe and Ni bonded NbC Laser Surface Engineered based Hardmetals: Alternative Cutter Materials for Electric Vehicle Applications
N2 - The efforts to substitute both tungsten carbide (WC) and cobalt (Co) has gained prominence in recent years due to the classification of Co as a carcinogen and the classification of Co and W as critical raw materials in the EU as well as within regulations of the U.S. National Toxicology Program. In this study, substitution of both WC and Co with advanced hardmetals consisting of NbC with Ni and Fe-based metal binders are investigated for their use of machining of metals used electric vehicle manufacturing. The developed NbC-Ni/Fe based hardmetals employ a Machining Property Led Tailored Design (MPLTD) approach. This reverse engineering strategy uses data from machining performance to guide the development of microstructural, mechanical, and behavioral properties. Four advanced NbC-based hardmetals were produced, two with Ni-based binders and two with Fe-based binders, along with two reference materials for comparison (WC-Co and straight NbC-12Ni). Hardmetals were characterized using field emission scanning electron microscopy (FE-SEM), annular dark-field scanning transmission electron microscopy (ADF-STEM), Vickers hardness, fracture toughness, and elastic moduli. Cutting tool inserts were manufactured from the developed hardmetals and enhanced using femto-second laser surface engineering. The inserts’ performance was evaluated through face milling tests on AZ31 automotive magnesium alloy, providing insights into their suitability for high-demand industrial applications.
T2 - 21. Plansee Seminar
CY - Reutte, Austria
DA - 01.06.2025
KW - Niobium carbide
KW - Alternative binders
KW - Alternative hard phases
KW - Face milling
KW - AZ31 magnesium alloy
PY - 2025
AN - OPUS4-65381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obenlüneschloß, Jorit
A1 - Boysen, Nils
A1 - Rönnby, Karl
A1 - Muriqi, Arbresha
A1 - Hoffmann, Volker
A1 - Abad Andrade, Carlos Enrique
A1 - Rogalla, Detlef
A1 - Brokmann, Ulrike
A1 - Rädlein, Edda
A1 - Nolan, Michael
A1 - Devi, Anjana
T1 - Ein seltener mononuklearer Lithium‐Carben‐Komplex für die Atomlagenabscheidung von lithiumhaltigen Dünnschichten
N2 - KurzfassungLithium ist das zentrale Element moderner Batterietechnologien, und die Herstellung von lithiumhaltigen Materialien mittels Atomlagenabscheidung (engl. Atomic Layer Deposition, ALD) bietet erhebliche Vorteile bei der Kontrolle der Schichtdicke und ‐zusammensetzung. In dieser Studie wird ein neuer mononuklearer, durch ein N‐heterocyclisches Carben (NHC) stabilisierter Lithiumkomplex, [Li(tBuNHC)(hmds)], als vielversprechender Präkursor für die ALD von lithiumhaltigen Dünnschichten vorgestellt. Die strukturelle Charakterisierung erfolgt durch den Vergleich von Dichtefunktionaltheorie (DFT) und Einkristall‐Röntgenbeugung (engl. Single‐Crystal X‐ray Diffraction, SC‐XRD), wobei die seltene mononukleare Struktur bestätigt wird. Thermogravimetrische Analysen (TGA) zeigen vorteilhafte thermische Eigenschaften für ALD‐Anwendungen. Die Verbindung weist einen niedrigen Schmelzpunkt, saubere Verdampfung und ermutigende Volatilitätsparameter im Vergleich zu anderen Lithium‐Präkursoren auf. ALD‐Experimente mit [Li(tBuNHC)(hmds)] und Ozon zeigen dessen Effektivität bei der Abscheidung von LiSixOy‐Filmen. Der ALD‐Prozess zeigt ein gesättigtes Wachstum pro Zyklus (engl. Growth per Cycle, GPC) von 0,95 Å. Die Zusammensetzung, analysiert mittels Rutherford‐Rückstreu‐Spektrometrie/Kernreaktionsanalyse (engl. Rutherford Backscattering Spectrometry/Nuclear Reaction Analysis, RBS/NRA), Röntgenphotoelektronenspektroskopie (engl. X‐ray Photoelectron Spectroscopy, XPS) und Glimmentladungsspektroskopie (engl. Glow Discharge Optical Emission Spectrometry, GD‐OES), bestätigt das Vorhandensein von Lithium und Silizium in den erwarteten Verhältnissen. Diese Arbeit stellt nicht nur einen neuen ALD‐Präkursor vor, sondern trägt auch zum Verständnis der Lithiumchemie bei und bietet Einblicke in die faszinierende Koordinationschemie und das thermische Verhalten von durch NHC‐Liganden stabilisierten Lithiumkomplexen.
KW - Atomlagenabscheidung
KW - N-heterozyklischer-Carben-(NHC)-stabilisierter Lithium-Präkursor
KW - Mononuklearer Li–Carben-Komplex
KW - Lithiumsilicat-Dünnfilme
KW - Filmanalytik/-Charakterisierung
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644045
DO - https://doi.org/10.1002/ange.202513066
SN - 0044-8249
N1 - Es gibt eine parallele Sprachausgabe (englisch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (English), a link is in the field related identifier
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64404
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obenlüneschloß, Jorit
A1 - Boysen, Nils
A1 - Rönnby, Karl
A1 - Muriqi, Arbresha
A1 - Hoffmann, Volker
A1 - Abad Andrade, Carlos Enrique
A1 - Rogalla, Detlef
A1 - Brokmann, Ulrike
A1 - Rädlein, Edda
A1 - Nolan, Michael
A1 - Devi, Anjana
T1 - Rare Mononuclear Lithium-Carbene Complex for Atomic Layer Deposition of Lithium Containing Thin Films
N2 - Lithium is the core material of modern battery technologies and fabricating the lithium‐containing materials with atomic layer deposition (ALD) confers significant benefits in control of film composition and thickness. In this work, a new mononuclear N‐heterocyclic carbene (NHC) stabilized lithium complex, [Li(tBuNHC)(hmds)], is introduced as a promising precursor for ALD of lithium‐containing thin films. Structural characterization is performed, comparing density functional theory (DFT) and single‐crystal X‐ray diffraction (SC‐XRD), confirming a rare mononuclear structure. Favorable thermal properties for ALD applications are evidenced by thermogravimetric analysis (TGA). The compound exhibits a low melting point, clean evaporation, and its volatility parameters are encouraging compared to other lithium precursors. ALD trials using [Li(tBuNHC)(hmds)] with ozone demonstrate its effectiveness in depositing LiSixOy films. The ALD process exhibits a saturated growth per cycle (GPC) of 0.95 Å. Compositional analysis using Rutherford backscattering spectrometry/nuclear reaction analysis (RBS/NRA), X‐ray photoelectron spectrometry (XPS), and glow discharge optical emission spectrometry (GD‐OES), confirms the presence of lithium and silicon in the expected ratios. This work not only presents a new ALD precursor but also contributes to the understanding of lithium chemistry, offering insights into the intriguing coordination chemistry and thermal behavior of lithium complexes stabilized by NHC ligands.
KW - Atomic layer deposition (ALD)
KW - N-heterocyclic carbene (NHC) ligands
KW - Lithium ALD precursor chemistry
KW - Mononuclear Li–carbene complex [Li(tBuNHC)(hmds)]
KW - Li-silicate thin films (LiSixOy)
KW - Thermal properties & TGA/volatility
KW - Compositional analysis (RBS/NRA, XPS, GD-OES)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643790
DO - https://doi.org/10.1002/anie.202513066
SN - 1433-7851
N1 - Es gibt eine parallele Sprachausgabe (deutsch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (German), a link is in the field related identifier
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
A1 - Hirsch, Philipp Daniel
A1 - Wassermann, Jonas
A1 - Heckel, Thomas
T1 - Automated self-adjustment of array probe with a robotic ultrasonic test system
N2 - Ultrasonic testing of objects with complex geometries often requires the use of a robotic arm to position the probe perpendicular to the local surface. Using immersion makes it possible to test these objects with standard ultrasonic linear array probes. Here, the probe positions and orientations provided by the robot are used for merging the locally acquired image data into a 3D-reconstruction. The quality of this reconstruction is highly dependent on the alignment of the position of the physical probe with the position used in the digital model. For common industrial tools, the tool center point (TCP) is usually acquired using geometric features of the tools. However, for ultrasonic arrays in immersion, there is a water standoff between the probe and the test object, therefore the TCP is in free space in front of the array and cannot be acquired with the common method. To overcome this challenge, we propose a method that allows the robotic ultrasonic system to automatically self-adjust the position and orientation of the ultrasonic probe using a test block made of steel with defined geometric features as a target for referencing. For each of the six degrees of freedom, a scan and adjustment routine are established using the data based on the actual ultrasound characteristics of the probe. Given a coarse pre-definition of the tool position and the known target test block, minimal human interaction is required to supervise the adjustment method, leading to higher quality reconstructions than with manual adjustment.
T2 - 20th World Conference On Non-Destructive Testing (WCNDT 2024)
CY - Incheon, South Korea
DA - 27.05.2024
KW - Testing
KW - Automation
KW - NDT 4.0
KW - Robotics
KW - Ultrasonic
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616387
UR - https://www.ndt.net/search/docs.php3?id=30309
SN - 1435-4934
SP - 1
EP - 9
PB - NDT.net
AN - OPUS4-61638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Genga, R. M.
A1 - Conze, S.
A1 - Berger, L.M.
A1 - Pötschke, J.
A1 - Witte, Julien
A1 - Schröpfer, D.
A1 - Cermak, A.
A1 - Zeman, P.
A1 - Ngongo, S.
A1 - Janse van Vuuren, A.
T1 - Enhanced Fe and Ni bonded NbC Laser Surface Engineered based Hardmetals: Alternative Cutter Materials for Electric Vehicle Applications
N2 - The efforts to substitute both tungsten carbide (WC) and cobalt (Co) has gained prominence in recent years due to the classification of Co as a carcinogen and the classification of Co and W as critical raw materials in the EU as well as within regulations of the U.S. National Toxicology Program. In this study, substitution of both WC and Co with advanced hardmetals consisting of NbC with Ni and Fe-based metal binders are investigated for their use of machining of metals used electric vehicle manufacturing. The developed NbC-Ni/Fe based hardmetals employ a Machining Property Led Tailored Design (MPLTD) approach. This reverse engineering strategy uses data from machining performance to guide the development of microstructural, mechanical, and behavioral properties. Four advanced NbC-based hardmetals were produced, two with Ni-based binders and two with Fe-based binders, along with two reference materials for comparison (WC-Co and straight NbC-12Ni). Hardmetals were characterized using field emission scanning electron microscopy (FE-SEM), annular dark-field scanning transmission electron microscopy (ADF-STEM), Vickers hardness, fracture toughness, and elastic moduli. Cutting tool inserts were manufactured from the developed hardmetals and enhanced using femto-second laser surface engineering. The inserts’ performance was evaluated through face milling tests on AZ31 automotive magnesium alloy, providing insights into their suitability for high-demand industrial applications.
T2 - 21. Plansee Seminar
CY - Reutte, Österreich
DA - 01.06.2025
KW - Niobium carbide
KW - Alternative binders
KW - Alternative hard phases
KW - Face milling
KW - AZ31 magnesium alloy
PY - 2025
VL - 2025
SP - 1
EP - 10
AN - OPUS4-65382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
T1 - Automatisierte Bahnplanung für robotergestützte Ultraschallprüfung mit Arrayprüfköpfen
N2 - In der automatisierten Ultraschallprüfung von Komponenten mit komplexen Oberflächengeometrien werden zur Führung des Prüfkopfes zunehmend 6-Achsen-Roboter erprobt. Diese stellen die notwendige Automatisierbarkeit und Flexibilität bereit, um die lokal senkrechte Einschallung sicherzustellen. Durch den Einsatz von linearen Arrays und bildgebenden Verfahren können die Bilder oder die daraus extrahierten Merkmale zu einer Rekonstruktion in 3D zusammengesetzt werden. Die Anforderungen an die Prüfbahnen für die bildgebende Array-Ultraschallprüfung gehen dabei über konventionellen Bahnplanungsprogramme hinaus. Es wird ein Prozess vorgestellt, der Roboterbahnen auf der Grundlage des 3D-Modells von Körpern mit doppelt gekrümmter Oberfläche unter Berücksichtigung der Prüfparameter erzeugt. Hierbei wird zum einen die senkrechte Prüfkopfstellung und zum anderen eine optimale Abdeckung der Oberfläche realisiert. Dabei wird die lokale Oberflächengeometrie beachtet, da diese das Reflexionsverhalten beeinflusst und sich daher auf die optimale Verteilung und Orientierung der Prüfpositionen auswirkt. Damit einhergehend erfolgt eine Ablösung von konventionellen Konzepten, die auf linearen Prüfbahnen basieren, welches spannende neue Prüfstrategien eröffnet.
T2 - DGZfP-Jahrestagung 2024
CY - Osnabrück, Germany
DA - 06.05.2024
KW - Ultraschallprüfung
KW - Phased array
KW - Automatisierung
KW - NDT 4.0
PY - 2024
AN - OPUS4-60590
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Campos de Oliveira, Paula
T1 - Advancing microstructural characterisation of ceramic cores for aerospace: from state-of-the-art to in-situ synchrotron X-ray computed tomography
N2 - Ceramic cores are crucial for manufacturing turbine blades in aircraft engines, creating intricate cooling channels that improve engine efficiency and reduce emissions. During high-temperature casting, the cores undergo significant microstructural changes, including phase transitions, particle rearrangements, and porosity transformations, which can affect their properties and must be carefully controlled. State-of-the-art characterisation techniques for ceramic cores mostly rely on 2D methods, such as scanning and transmission electron microscopy. While valuable, these methods are limited in capturing the 3D complexity of the material. Advances in X-ray computed tomography (XCT) offer a more comprehensive perspective on 3D microstructures, but conventional XCT often lacks the resolution and in-situ capabilities to study microstructural evolution under casting conditions. Synchrotron XCT (SXCT) addresses these limitations, offering high spatial and temporal resolution with features down to 1 µm, enabling in-situ investigations. This study highlights the potential of SXCT, revealing previously unseen 3D microstructural features in ceramic cores, such as agglomeration, porosity evolution, surface reactions, microcracking, and particle orientation. These findings provide a more realistic view of dynamic changes during casting, advancing the understanding of core behaviour. Despite its advantages, SXCT is still rarely used in the field due to challenges such as limited access to synchrotron facilities and sample movement artifacts. Future developments, including high-temperature and vacuum compatible CT setups, could enhance this technique, leading to a better optimisation of ceramics performance.
T2 - XIXth Conference of the European Ceramic Society (ECERS 2025)
CY - Dresden, Germany
DA - 31.08.2025
KW - Synchrotron
KW - X-ray Computed Tomography
KW - Ceramic core
KW - Aerospace
KW - Microstructure
PY - 2025
AN - OPUS4-64050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sprengel, Maximilian
T1 - Determination and assessment of residual stress in laser powder bed fused stainless steel
N2 - This presentation shows the effect of geometry scaling on the formation and distribution of the residual stress in laser powder bed fused 316L.
T2 - BMDK - Doktorandenseminar der Otto-Von-Guericke-Universität Magdeburg
CY - Online meeting
DA - 26.01.2022
KW - Stainless Steel
KW - AGIL
KW - Residual Stress
KW - X-ray and Neutron Diffraction
KW - Additive Manufacturing
PY - 2022
AN - OPUS4-54261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
A1 - Mouiya, Mossaab
A1 - Prasek, Marco
A1 - Kupsch, Andreas
A1 - Bruno, Giovanni
T1 - High temperature in-situ heat treatment of a refractory material by means of synchrotron refraction radiography
N2 - The stress–strain behavior of certain ceramics, such as aluminum titanate (AT, Al2TiO5), has features that are unusual for brittle material. In particular, a substantial nonlinearity under uniaxial tension, and load–unload hysteresis caused by the increase of the incremental stiffness at the beginning of unloading. These features are observed experimentally and attributed to microcracking. In this study, we investigate the mechanical response of an AT material at room and high temperature. Microstructure and microcracking are analyzed by means of electron microscopy, and both synchrotron micro computed tomography (µCT) and refraction radiography (SXRR). Synchrotron refraction radiography is combined with in-situ heating at high-temperatures (up to 1400°C) to be able to monitor the relative closure of microcracks as a function of increasing/decreasing temperatures.
T2 - ECCM21
CY - Nantes, France
DA - 02.07.2024
KW - Refractory materials
KW - Microcracking
KW - Synchrotron µCT and refraction radiography
KW - In-situ heating up to 1400°C
PY - 2024
UR - https://gem.ec-nantes.fr/en/eccm21-proceedings/
SN - 978-2-912985-01-9
DO - https://doi.org/10.60691/yj56-np80
SP - 47
EP - 53
PB - The European Society for Composite Materials (ESCM) and the Ecole Centrale de Nantes.
CY - Nantes
AN - OPUS4-60581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Residual stresses and micromechanical properties of additively manufactured metals: why do we need a paradigm shift?
N2 - An overview of the challenges and successes in the methodology to characherise residual stresses and micromechnical properties in additively manufactured metals
T2 - CAM2 Annual Seminar 2022 - 5-year journey
CY - Gothenburg, Sweden
DA - 24.10.2022
KW - Additive Manufacturing
KW - Residual stress
KW - AGIL
KW - MANUFACT
KW - Micromechnical properties
PY - 2022
AN - OPUS4-56466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - X-ray refraction techniques non-destructively quantify and classify defects in am materials
N2 - X-ray refraction is analogous to visible light deflection by matter; it occurs at boundaries between different media. The main difference between visible light and X-rays is that in the latter case deflection angles are very small, from a few seconds to a few minutes of arc (i.e., the refraction index n is near to 1). Importantly, deflection of X-rays is also sensitive to the orientation of the object boundaries. These features make X-ray refraction techniques extremely suitable to a) detect defects such as pores and microcracks and quantify their densities in bulk (not too heavy) materials, and b) evaluate porosity and particle properties such as orientation, size, and spatial distribution (by mapping). While X-ray refraction techniques cannot in general image single defects, they can detect objects with size above a few wavelengths of the radiation.
Such techniques, especially at the Synchrotron BESSY II, Berlin, Germany, can be used in-situ, i.e. when the specimen is subjected to temperatures or external loads.
The use of X-ray refraction analysis yields quantitative information, which can be directly input in kinetics, mechanical and damage models.
We hereby show the application of non-destructive X-ray refraction radiography (SXRR, 2D mapping also called topography) to problems in additive manufacturing:
1) Porosity analysis in PBF-LM-Ti64. Through the use of SXRR, we could not only map the (very sparse) porosity distribution between the layers and quantify it, but also classify, and thereby separate, the filled porosity (unmolten powder) from the keyhole and gas pores (Figure 1).
2) In-situ heat treatment of laser powder bed fusion PBF-LM-AlSi10Mg to monitor microstructure and porosity evolution as a function of temperature (Figure 2). By means of SXRR we indirectly observed the initial eutectic Si network break down into larger particles as a function of increasing temperature. We also could detect the thermally induced porosity (TIP). Such changes in the Si-phase morphology upon heating is currently only possible using scanning electron microscopy, but with a much smaller field-of-view. SXRR also allows observing the growth of some individual pores, usually studied via X-ray computed tomography, but again on much smaller fields-of-view.
Our results show the great potential of in-situ SXRR as a tool to gain in-depth knowledge of the defect distribution and the susceptibility of any material to thermally induced damage and/or microstructure evolution over statistically relevant volumes.
T2 - AAMS 2023
CY - Madrid, Spain
DA - 27.09.2023
KW - X-ray refraction radiography
KW - Defects
KW - Large scale facilities
KW - Computed tomography
PY - 2023
AN - OPUS4-58508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
T1 - Röntgenrefraktionstechnik - Charakterisierung von Keramiken und Verbundwerkstoffen
N2 - Die Brechung von Röntgenstrahlen (Röntgenrefraktion) an Grenzflächen zwischen Materialien unterschiedlicher Dichte ist analog zur Ablenkung von sichtbarem Licht an z.B. Glasoberflächen. Es gibt jedoch zwei wesentliche Unterschiede:
a) konvexe Grenzflächen verursachen Divergenz (d.h. der Brechungsindex n ist kleiner als 1), und
b) die Ablenkungswinkel sind sehr klein, und reichen von einigen Bogensekunden bis zu einigen Bogenminuten (d.h. n ist nahe bei 1);
Wie auch bei sichtbarem Licht ist die Ablenkungsrichtung der Röntgenstrahlen abhängig von der Orientierung der durchstrahlten Grenzfläche. Aufgrund dieser Eigenschaften eignen sich Röntgenrefraktionsmethoden hervorragend für:
a) die Erkennung und Quantifizierung von Defekten wie Poren und Mikrorissen und
b) die Bewertung von Porosität und Partikeleigenschaften wie Orientierung, Größe und räumliche Verteilung.
Wir zeigen die Anwendung der Röntgenrefraktionsradiographie (2,5D Technik) und der -tomographie (3D Technik) für die Untersuchung verschiedener Probleme in der Werkstoffwissenschaft und -technologie:
a) Sintern von SiC-Grünkörpern
b) Porositätsanalyse in Dieselpartikelfiltersilikaten
c) Faser-Matrix-Haftung in Metall- und Polymermatrixverbundwerkstoffen
d) Mikrorissbildung in Glaskeramik.
Wir zeigen, dass der Einsatz von Röntgenrefraktionsmethoden quantitative Ergebnisse liefert, die direkt als Parameter in Werkstoffmodellen verwendet werden können.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Röntgen-Refraktion
KW - Verbundwerkstoffe
KW - Keramik
PY - 2023
AN - OPUS4-57615
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - Analysis of damage processes in concrete - What can CT do?
N2 - In this talk the basics of X-ray computed tomography (XCT) are presented, together with a description of complementary techniques such as Laminography and Stereoradiography.
A overview of the common reconstruction approach and of the artifacts that can occur during reconstruction or acquisition of XCT images is also given.
Finally, application examples in the field of construction materials are given, whereby several experimental techniques (Region of Interest Approach) and data analysis methods (e.g. Digital volume correlation) are explained. Such techniques and algorithms are used to extract quantitative information from ex- and in-situ experiments.
T2 - Seminar DFG GRK 2250/1 Summer School
CY - Online meeting
DA - 21.06.2021
KW - Asphalt, porosity
KW - Concrete
KW - 3D rendering
KW - Crack segmentation
KW - Water uptake
PY - 2021
AN - OPUS4-52837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voloskov, Boris
A1 - Mishurova, Tatiana
A1 - Evlashin, Stanislav
A1 - Bruno, Giovanni
A1 - Sergeichev, Ivan
T1 - Influence of artificial and process-induced defects on very high cycle fatigue characteristics of 316L stainless steel produced by laser powder bed fusion
N2 - This study investigates the impact of artificially embedded defects on the very high cycle fatigue (VHCF) of 316L stainless steel produced by laser powder bed fusion (PBF-LB) technology. Each specimen contains a single embedded artificial defect of 180 μm or 350 μm in diameter, positioned at specific distances from the surface (ranging from 350 μm to 1200 μm). The defect position and size are quantified by X-ray computed tomography.
Following VHCF testing, the fracture surfaces of the specimens are examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) with electron diffraction analysis. The results demonstrate that the fracture surfaces predominantly display a fish-eye fracture type, with a fine granular area (FGA) surrounding the internal defects, typical for VHCF. The FGAs dimensions including thickness are estimated by means of microscopy analysis. However, despite the presence of relatively large artificial defects, cracks sometimes initiate from much smaller process-induced defects closer to the surface than the artificial ones. In conclusion, our study quantifies the relationship between the probability of crack initiation from artificial defects and the distance of the artificial defect from the specimen’s surface.
KW - Additive manufacturing
KW - X-ray CT
KW - Porosity
PY - 2025
DO - https://doi.org/10.1016/j.msea.2024.147571
VL - 920
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-62117
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Residual stresses Analysis in Additively Manufactured alloys using neutron diffraction (L-PBF)
N2 - An overview of recent progress at BAM of residual stress analysis in additively manufactured, in particular Laser Powder Bed Fusion of metallics materials, using neutron diffraction will be presented. This will cover important topics of the stress-free reference, the diffraction elastic moduli and principal stress determination.
T2 - AWT-Fachausschuss 13 "Eigenspannungen"
CY - Berlin, Germany
DA - 28.03.2023
KW - AGIL
KW - Residual stress
KW - Additive manufacturing
KW - Laser Powder Bed Fusion
KW - Diffraction
PY - 2023
AN - OPUS4-59177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Diffraction based residual stress analysis: challenges and opportunities in additive manufacturing
N2 - This presentation overviews the challanges and opportunities of diffraction based residual stress analysis for additively manufactured metals. Through examples, the challanges and respective solutions are presented and the opportunities that the presented methods allow are described.
T2 - Workshop on Advanced Manufacturing (WAM) 2025
CY - Grenoble, France
DA - 03.06.2025
KW - Residual stress
KW - Diffraction
KW - AGIL
KW - Laser powder bed fusion
KW - MANUFACT
PY - 2025
AN - OPUS4-64137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - Peculiarities of the determination of residual stress in additively manufactured materials
N2 - The determination of residual stress in additively manufactured materials is a challenge, even after decades from the establishment of the basics of residual stress analysis. This is due to the peculiar microstructure of such materials. In fact, researchers have discovered that conventional methods for the determination of RS in materials do not properly work for AM materials. In this tutorial, the basics of RS analysis will be explained, together with the basics of AM manufacturing techniques. The microstructure of the peculiar materials (AM) dealt with here will be elucidated. Successively, the necessary modifications to the conventional approaches to RS analysis will be explained and case studies will be displayed, for the attendant to touch with hands the peculiarities of the approaches. Finally, a few experimental and theoretical tips will be given on dos and don’ts for a correct determination of RS in AM materials.
T2 - 11th European Conference on Residual Stresses
CY - Prague, Czech Republic
DA - 03.06.2024
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Residual Stress
KW - Diffraction
PY - 2024
AN - OPUS4-60428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - The heat treatment of L-PBF Inconel 718: A manyfold problem
N2 - The interest to additively manufacture Nickel-based superalloys has substantially grown within the past decade both academically and industrially. More specifically, additive manufacturing processes such as laser powder bed fusion (LPBF) offer the ability to produce dense parts within a single manufacturing step. In fact, the exceptional freedom in design associated with the layer-based nature of the processes is of particular interest for the complex shapes typically required in turbine applications. In certain cases, the overall part performance can be achieved by tailoring the microstructure and the crystallographic texture to the specific application. However, these advantages must be paid at a price: the large local temperature gradients associated with the rapid melting and solidification produce parts that inherently contain large residual stress in the as-manufactured state. In addition, the presence of pores in the final part may further affect the in-service part failure. As among Nickel-based alloys Inconel 718 exhibits excellent weldability, this alloy has been widely studied in open research in the domain of LPBF. However, significant microsegregation of the heavier alloying elements such as Niobium and Molybdenum accompanied by dislocation entanglements may preclude the application of conventional heat treatment schedules. Therefore, different post processing heat treatments are required for laser powder bed fused Inconel 718 as compared to conventional variants of the same alloy.
In this study, we investigated two different heat treatment routes for LPBF Inconel 718. In a first routine, the samples were stress relieved and subsequently subjected to hot isostatic pressing (HIP) followed by a solution heat treatment and a two-step age (referred to as FHT). In a second routine, the samples were subjected to a single-step direct age post stress relieving heat treatment (referred to DA). We investigated the consequences of such heat treatment schedules on the microstructure, texture, and mechanical behavior. We show that by applying a DA heat treatment the typical columnar microstructure possessing a crystallographic texture is retained, while an equiaxed untextured microstructure prevails in case of an FHT heat treatment. We further evaluate how these heat treatments affect the mechanical behaviour on the macroscopic and microscopic scale.
T2 - 4th European Symposium on Superalloys and their Applications EuroSuperalloys 2022
CY - Bamberg, Germany
DA - 18.09.2022
KW - Electron Backscatter Diffraction
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Mechanical Behavior
KW - Heat Treatment
KW - X-Ray Diffraction
PY - 2022
AN - OPUS4-55811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - A paradigm shift in the description of creep in metals can only occur through multi-scale imaging
N2 - The description of creep in metals has reached a high level of complexity; fine details are revealed by all sorts of characterization techniques and different theoretical models. However, to date virtually no fully microstructure-driven quantitative description of the phenomenon is available. This has brought to interesting inconsistencies; the classic description of (secondary) creep rests on the so-called power law, which however: a- has a pre-factor spanning over 10 orders of magnitude; b- has different reported exponents for the same material; c- has no explanation for the values of such exponents.
Recently, a novel description (the so-called Solid State Transformation Creep (SSTC) Model) has been proposed to tackle the problem under a different light. The model has two remarkable features: 1- it describes creep as the accumulation of elementary strains due to dislocation motion; 2- it predicates that creep is proceeding by the evolution of a fractal arrangement of dislocations. Such description, however, needs a great deal of corroborating evidence, and indeed, is still incomplete.
To date, we have been able to observe and somehow quantify the fractal arrangement of microstructures through Transmission Electron Microscopy (TEM), observe the accumulation of dislocations at grain boundaries by EBSD-KAM (Electron Back-Scattered Diffraction-Kernel Angular Misorientation) analysis, quantify the kinetic character (solid state transformation) of experimental creep curves, and estimate the sub-grain size of the fractal microstructure through X-ray refraction techniques. All pieces of the mosaic seem to yield a consistent picture: we seem being on the right path to reconstruct the whole elephant by probing single parts of it. What is still missing is the bond between the various scales of investigation.
T2 - Korrelative Materialcharakterisierung 2022
CY - Dresden, Germany
DA - 13.10.2022
KW - X-ray refraction
KW - EBSD
KW - Alloys
KW - TEM
KW - SEM
PY - 2022
AN - OPUS4-56163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Jakob
T1 - On the influence of heat treatment on microstructure and mechanical behavior of laser powder bed fused Inconel 718
N2 - Since additive manufacturing processes typically introduce heterogeneous microstructures and residual stresses, the applicability of parts produced in an as-built state is limited. Therefore, often different post-processing treatments are necessary to obtain the desired stress state and properties.
For additively manufactured Inconel 718, the recently developed standard ASTM F3301 provides guidance for the heat treatment of powder bed fusion specimens. Although this standard is based on standards developed for wrought Inconel 718, it does not include the direct aging variant. In this study, we characterized the microstructure and tensile behavior of Inconel 718 specimens produced by a laser powder bed fusion process. The specimens were heat-treated according to two different routines after stress relieving: a full heat treatment cycle versus a one-step aging process. Differences in the resulting texture and grain morphology were observed. Although these differences prevail, the ex-situ tensile behavior was broadly similar. Minor differences were observed in yield strength and work hardening rate for the direct aged specimen. In order to understand this behavior, investigations with in-situ tensile testing during synchrotron energy-dispersive X-ray diffraction measurements revealed differences in the load partitioning among different crystal directions. This was attributed to microstructural differences between the heat treatment variants. Further analysis emphasized that the various strengthening mechanisms are present to a different extent depending on the heat-treatment cycle applied. In addition, the elastic anisotropy expressed by the differences in the diffraction elastic constants displayed a dependence on the microstructure. Importantly, a precise knowledge of such constants is indispensable to reliably determine residual stresses in parts.
T2 - EUROMAT 2021 - European Congress and Exhibition on Advanced Materials and Processes
CY - Online meeting
DA - 13.09.2021
KW - Electron microscopy
KW - X-ray analysis
KW - Inconel 718
KW - Additive manufacturing (AM)
KW - Mechanical behavior
KW - Diffraction elastic constants (DECs)
PY - 2021
AN - OPUS4-53301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hejazi, Bardia
A1 - Fritsch, Tobias
A1 - Benz, Christopher
A1 - Radtke, Lars
A1 - Sander, Manuela
A1 - Bruno, Giovanni
T1 - In-situ very high cycle fatigue experiments of additively manufactured Ti-6Al-4V using X-ray computed tomography
N2 - X-ray computed tomography (XCT) is an invaluable method for evaluating the properties and performance of components both during service and after failure in a non-destructive manner. XCT is particularly useful for the investigation of additively manufactured (AM) components, which often have production defects that are inherent to the manufacturing process, such as lack of fusion defects. Understanding the mechanisms of fatigue crack growth throughout the life cycle of such components is crucial and so to address this need, we designed and performed experiments to investigate the fatigue life and fatigue crack growth behavior of Ti-6Al-4V components under very high cycle fatigue (VHCF) testing. The titanium samples were additively manufactured with intentional internal defects to control crack initiation location. XCT of the component was carried out to identify crack initiation sites and characterize the dynamics of crack growth. The findings from this work will benefit industries that rely on the AM of titanium alloys, aiding in the improvement of component design and manufacturing processes.
T2 - Alloys for additive manufacturing 2025 (AAMS 2025)
CY - Neuchâtel, Switzerland
DA - 02.09.2025
KW - X-ray computed tomography
KW - Deep learning
KW - Titanium alloy
KW - Very high-cycle fatigue
PY - 2025
DO - https://doi.org/10.5281/zenodo.15261296
AN - OPUS4-64096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Wang, Shu
A1 - Radnik, Jörg
A1 - You, Yi
A1 - Resch-Genger, Ute
T1 - Assessing the protective effects of different surface coatings on NaYF4:YB3+, Er3+, upconverting nanoparticles in buffer and DMEM
N2 - We studied the dissolution behavior of β NaYF4:Yb(20%), Er(2%) UCNP of two different sizes in biologically relevant media i.e., water (neutral pH), phosphate buffered saline (PBS), and Dulbecco’s modified Eagle medium (DMEM) at different temperatures and particle concentrations. Special emphasis was dedicated to assess the influence of different surface functionalizations, particularly the potential of mesoporous and microporous silica shells of different thicknesses for UCNP stabilization and protection. Dissolution was quantified electrochemically using a fluoride ion selective electrode (ISE) and by inductively coupled plasma optical emission spectrometry (ICP OES). In addition, dissolution was monitored fluorometrically. These experiments revealed that a thick microporous silica shell drastically decreased dissolution. Our results also underline the critical influence of the chemical composition of the aqueous environment on UCNP dissolution. In DMEM, we observed the formation of a layer of adsorbed molecules on the UCNP surface that protected the UCNP from dissolution and enhanced their fluorescence. Examination of this layer by X ray photoelectron spectroscopy (XPS) and mass spectrometry (MS) suggested that mainly phenylalanine, lysine, and glucose are adsorbed from DMEM. These findings should be considered in the future for cellular toxicity studies with UCNP and other nanoparticles and the design of new biocompatible surface coatings.
KW - Fluorescence
KW - Lifetime
KW - Method
KW - Quantification
KW - Stability
KW - Coating
KW - Surface chemistry
KW - Lanthanide
KW - Fluoride
KW - Electrochemistry
KW - ICP-OES
KW - Upconversion
KW - Nano
KW - Particle
KW - Aging
KW - Quality assurance
KW - Mass spectrometry
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515984
DO - https://doi.org/10.1038/s41598-020-76116-z
SN - 2045-2322
VL - 10
IS - 1
SP - 19318-1
EP - 19318-11
PB - Springer Nature
CY - London
AN - OPUS4-51598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Onyenso, Gabriel
A1 - AI-Zawity, Jiwar
A1 - Farahbakhsh, Nastaran
A1 - Schardt, Annika
A1 - Yadigarli, Aydan
A1 - Vakamulla Raghu, Swathi Naidu
A1 - Engelhard, Carsten
A1 - Müller, Mareike
A1 - Schönherr, Holger
A1 - Killian, Manuela S.
T1 - Novel Ag-modified zirconia nanomaterials with antibacterial activity
N2 - The outcome of an implant procedure largely depends on the implant's surface properties. Biomaterials are now designed to have surfaces with multifunctionality, such as favorable tissue integration and the ability to combat bacterial adhesion and colonization. Herein, we report on a simple approach to improve the antibacterial properties of zirconia nanotubes (ZrNTs) coatings by decorating with silver nanoparticles (AgNP), achieved through electrochemical anodization of a zirconium–silver alloy (Zr–Ag). The AgNPs were shown to partially consist of Ag2O, potentially enhancing the availability of Ag+ ions for antibacterial activity. The modified ZrNTs were characterized using SEM, EDS, ToF-SIMS, and XPS to determine their structural morphology and chemical composition, and were further subjected to antibacterial testing. The silver and zirconium ion release behavior was monitored via ICP-MS. ZrNTs decorated with AgNP exhibit strong antimicrobial activity (>99% bacterial killing) against both S. aureus and E. coli. Antimicrobial tests indicate that the antibacterial activity against the Gram-positive pathogen S. aureus was improved by a factor of 100 compared to unmodified ZrNTs, while unmodified ZrNTs already showed a comparable reduction of viable Gram-negative E. coli. This strategy illustrates a straightforward and effective modification that optimizes the interface between the host environment and the biomaterial surface to meet the very important criteria of biocompatibility and active antibacterial response.
KW - Mass Spectrometry
KW - Nanoparticles
KW - Advanced Materials
KW - ICP-MS
KW - Antimicrobial material
KW - ToF-SIMS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653990
DO - https://doi.org/10.1039/d5ra07099f
SN - 2046-2069
VL - 16
IS - 3
SP - 2286
EP - 2297
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - Thermographic Methods for In-situ Monitoring of Metal-based Additive Manufacturing Processes
N2 - Additive manufacturing (AM) with metals creates new, exciting opportunities for industrial applications. Especially industries with high relevance for the future like transport and energy benefit from optimized designs and novel materials. However, a reliable in-situ quality assurance for metal AM is still missing while process optimization is slow. This directly hinders the huge potential of metal AM technologies. A promising method to counteract this issue is the investigation of the emitted thermal radiation. It is optimal for monitoring and understanding the thermal history of the high-temperature AM process. The thermal history holds virtually all information about the properties and the quality of the manufactured components. The thermal information is also highly valuable for tuning and validating numerical simulations to gather further insights into the process. Despite this importance, the usage of thermal radiation in commercial AM machines is only marginal (like simple pyrometry or long-time exposure for optical tomography (OT) at a single wavelength). Based on this deficit and potential, this work gives an overview of the research in division “8.3 Thermographic Methods” at the Bundesanstalt für Materialforschung und -prüfung (BAM) in Berlin, Germany. Different wavelengths of the thermal radiation are investigated: the visible range (VIS), the short-wave infrared (SWIR), and the mid-wave infrared (MWIR) with their respective optimal field of application. Focus lies on laser powder bed fusion of metals (PBF-LB/M), but directed energy deposition with laser beam (DED-LB/M) is investigated as well. The presented research is performed not only on commercial AM machines, but also on an in-house developed PBF-LB/M research system specifically designed for sensor testing. This ensures an exciting mélange of applied research for industrial applications, and fundamental research for process understanding and validation. Therefore, a crucial contribution to industrial and scientific insights of metal AM is given.
T2 - Sim-AM 2025
CY - Pavia, Italy
DA - 09.09.2025
KW - Laser powder bed fusion
KW - Direct energy deposition
KW - Quality assurance
KW - Infrared thermography
PY - 2025
AN - OPUS4-65391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
T1 - Klein, heiß und schnell: Bestimmung von Realtemperaturen in der metallbasierten additiven Fertigung mittels hyperspektraler Thermografie
N2 - Die additive Fertigung von Metallen mittels Laser Powder Bed Fusion (PBF LB/M) ermöglicht die Herstellung komplexer Geometrien und die Nutzung neuartiger Legierungen. Die dabei lokal im Prozess auftretenden Temperaturverteilungen beeinflussen maßgeblich die Bauteileigenschaften sowie die Entstehung von Defekten wie bspw. Risse und Poren. Eine quantitative Bestimmung der Realtemperaturen ist daher essenziell für Prozessvalidierung und -vergleich sowie die Qualitätssicherung und das Verständnis der zugrunde liegenden physikalischen Vorgänge. Bisherige thermografische Monitoring-Ansätze liefern jedoch meist nur qualitative Informationen. Hintergrund sind die Herausforderungen gegeben durch den Prozess: kleine Schmelzbäder (< 300 µm), hohe Temperaturen (> 2500 K) und hohe Scangeschwindigkeiten (ca. 1 m/s). Zusammen mit den dynamischen Änderungen des Emissionsgrads u.a. durch Phasenübergänge ergeben sich äußerst schwierige Bedingungen für thermografische Messungen.
Um dieser Herausforderung zu begegnen, verfolgen wir einen neuartigen Ansatz zur hyperspektralen Thermografie, der eine simultane Messung der emittierten Strahlung im kurzwelligen Infrarotbereich (1 bis 1,6 µm) entlang einer Linie bei ca. 20 kHz ermöglicht. Durch die Bewegung des Schmelzbades senkrecht durch die Messlinie kann ein typisches Schmelzbad rekonstruiert werden. Die Temperatur-Emissionsgrad-Separation (TES) erlaubt dabei die Bestimmung von Realtemperaturen und Emissionsgraden basierend auf parametrisierten spektralen Emissionsgradfunktionen sowie radiometrischen Kalibrationen. Die Umsetzung erfolgt an der Forschungsmaschine der BAM „SAMMIE“, die speziell für thermografische Messungen am PBF LB/M-Prozess konzipiert wurde.
Die Ergebnisse zeigen das Potenzial der hyperspektralen Thermografie zur Erfassung von Realtemperaturen im Prozess. Dies stellt einen wichtigen Schritt zur verbesserten Vergleichbarkeit und Wiederholbarkeit der Fertigung sowie zur Validierung komplexer Simulationen dar. Damit trägt der neuartige Ansatz langfristig zur Erhöhung der Sicherheit und des Verständnisses additiver Fertigungsprozesse bei.
T2 - Thermo 25
CY - Garching bei München, Germany
DA - 12.11.2025
KW - Laser powder bed fusion
KW - Infrarot Thermografie
KW - In-situ Monitoring
KW - Qualitätssicherung
KW - Temperaturmessung
PY - 2025
AN - OPUS4-65394
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Stoian, R.
A1 - Bonse, Jörn
T1 - Ultrafast Laser Nanostructuring — The Pursuit of Extreme Scales
N2 - Long seen as “a solution seeking a problem,” laser pulses are nowadays – more than 60 years after their first practical demonstration – paramount in shaping and structuring matter. Harnessing their capabilities to direct intense beams of light, the number of scientific and technological developments and daily-life applications is continuously increasing. Today, the presence of lasers is ubiquitous in all sites of scientific and technological interest, from the most advanced research laboratories to industrial factories and medical hospitals.
The directionality of the laser beam determines equally a local character on lightmatter interaction and as such a local modification to a material target. Furthermore, the coherence of laser radiation enables near-field or far-field scattering and interference effects that widen significantly the capabilities of controlling and tracking laser-matter interactions in space and time. Already with the advent of lasers, powerful beams of light have been directed at solid materials for a variety of purposes, making this application as old as the laser itself. The roots of the major applications for laser structuring were developed already in the 1960s, setting the base of both theoretical and experimental studies on laser ablation, with the number of publications expanding explosively during the next decades.
Within this dynamic context, laser processing of materials experienced an impressive development over the years. Laser processing means specifically the capability to structure and tailor a material on its surface or even within its volume, rendering new functions and properties that are impacting the mechanical, electrical, or optical characteristics of the material. These properties are scaledependent, generating thus over the years an equally impressive quest for spatial or temporal resolution. Therefore, the developments in laser engineering with major breakthroughs, notably in pulse duration and power, always closely accompanied the efforts in material structuring with two milestones in sight: (1) yield and (2) resolution. Every step in shrinking the laser pulse duration led to a subsequent strong-impact development in process precision – particularly when the ultrashort pulse durations surpassed the fundamental electron-phonon relaxation times. Thus, minimizing heat diffusion, the advent of pulses with duration smaller than molecular or lattice vibration times has managed to confine the spatial resolution to the optical diffraction limit and sometimes even beyond. The nanoscale was already in sight at the turn of the millennium. An important question may be raised now; is there any fundamental limit in the processing resolution, a barrier defined by the intrinsic properties of light and matter? The answer has an inherently multidisciplinary nature, following the conversion of free-propagating electromagnetic radiation into
material-confined energy potentially usable to drive or transform matter, and will be the focus of the present book.
Relying on the experience and expertise of the leading researchers in the field, the present book intends to explore the current efforts in achieving laser processing resolution beyond the diffraction limit, laying down a perspective towards extreme laser nanostructuring. Following the most recent advances and developments, it puts forward a concept of extreme processing scales enabled by optical pulses that are able to bypass diffraction limits and achieve structuring characteristic scales beyond 100 nm. This objective can be achieved by a comprehensive understanding on how light can change matter and how, in turn, matter can change light, allowing jointly for actively controlling light and material processes. In order to give an extended perspective on the current state-of-the-art in the field of precision laser structuring, the book is divided into three main parts.
The first part of the book (Part I: Fundamental Processes) offers a perspective into the fundamentals of laser-matter interaction on extreme spatial scales, with a description of the most advanced modeling efforts in understanding energy deposition in matter, a plethora of material-relaxation pathways, as well as advanced concepts for probing and observing matter in motion. Roadmaps for energy localization will be developed, and the atomistic perspective of laser ablation visualized. Theoretical modelling enables in-depth insights on ultrafast quantum processes at the nanoscale. Laser-driven self-organization at surfaces will be dissected regarding the question of how light drives material periodic patterns down to the nanoscale, explored and transmitted to its ultimate limits of an atomic printer, and immediately complemented by the unprecedented capabilities of ultrafast in-situ observation approaches for tracking the laser-induced material response with extreme spatial and temporal resolution.
In the second part of the book (Part II: Concepts of Extreme Nanostructuring), distinct concepts will be developed and explored that allow confinement of light and harnessing of a material response restricted to nano- or mesoscopic scales at surfaces or in the volume of irradiated materials. A special focus will be on optical near-field related approaches for localizing light on scales even below the optical diffraction limit and plasmonic printing. Spatial and temporal beam-shaping and tailored interference techniques are discussed in the context of ultrashort laser pulses, and insights into some extreme states of matter realized by the tight confinement of laser energy are presented. The ultimate limits of writing waveguides in the bulk of dielectrics and for manifesting 3D-nanolithography are elucidated. Plasma-based surface treatments can significantly enhance the vertical precision of surface processing through etching processes.
Finally, the third part of the book (Part III: Applications) leads us to a number of resuming applications, unveiling the tremendous capabilities of surface functionalization through laser micro- and nanostructuring, assessing the 3D-writing of waveguides in the bulk of dielectrics or semiconductors for enabling new branches of integrated photonics, and summarizing related applications ranging from nanophotonics to nanofluidics and from optical sensing to biomedical applications, including the latest capabilities of refractive eye surgery. This part will analyze the applications’ compatibility in yield and reproducibility with current industrial requirements, costs, and intellectual property aspects. It expands the involved spatial scales by more than eight orders of magnitude, when extending extremely small structures featuring sizes of few tens of nanometers to larger dimensions in the meter range.
Thus, from surfaces to the bulk, from subtractive to additive manufacturing approaches, from advanced theoretical frames to practical technological processes – we invite the readers here to an exciting journey into the varicolored landscape of extreme laser nanostructuring.
The idea of this book project was seeded in early 2020. We were delighted about the numerous and extremely positive responses from the laser-processing community, quickly receiving commitments for more than 30 individual book chapters. About 2500 communications later, the book is published. We would like to thank all authors of this book project for their insightful and detailed chapters, reviewing and reporting on this fascinating topic of the pursuit of extreme scales in ultrafast laser nanostructuring. Moreover, we would like to acknowledge the professional help and guidance of the staff of Springer Nature. Finally, we hope you will enjoy reading this book as much as we have enjoyed putting it together.
Saint Etienne, France Razvan Stoian
Berlin, Germany Jörn Bonse
December 2022
KW - Laser nanostructuring
KW - Surface engineering
KW - Nonlinear lithography
KW - Self-organization
KW - Laser-induced periodic surface structures, LIPSS
PY - 2023
SN - 978-3-031-14752-4
SN - 978-3-031-14751-7
DO - https://doi.org/10.1007/978-3-031-14752-4
SN - 0342-4111
VL - 239
SP - 1
EP - 1245
PB - Springer Nature Switzerland AG
CY - Cham
ET - 1
AN - OPUS4-57294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hörenz, Christoph
A1 - Tache, O.
A1 - Bartczak, D.
A1 - Nunez, S.
A1 - Abad Alvaro, I.
A1 - Goenaga-Infante, H.
A1 - Hodoroaba, Vasile-Dan
T1 - A Study on the Analysis of Particle Size Distribution for Bimodal Model Nanoparticles by Electron Microscopy
N2 - The present study addresses the capability of measurement of relative particle number concentration by scanning electron microscopy for model bimodal silica and gold samples prepared in the frame of the European research project “nPSize - Improved traceability chain of nanoparticle size measurements” as candidate reference nanoparticles.
KW - Nanoparticles
KW - Particle size distribution
KW - Bimodal size distribution
KW - Traceability
PY - 2020
DO - https://doi.org/10.1017/S1431927620021054
VL - 26
IS - S2
SP - 2282
EP - 2283
PB - Cambridge University Press
CY - Cambridge, UK
AN - OPUS4-51771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörenz, Christoph
T1 - Improved Sample Preparation for the Analysis of Nanoparticles by Electron Microscopy
N2 - Various promising sample preparation procedures aiming to avoid drying artifacts and guarantee homogeneously distributed NP samples for imaging techniques like TEM, SEM or AFM are presented. This involves retarded drying in an environment of high relative humidity as well as spin coating or freeze drying of the sample on the substrate.
Depending on the type of the NPs, different techniques are successful in obtaining homogenous sample deposition. Simple drying at ambient conditions often results in heavily agglomerated NPs densely packed in coffee ring traces. Retardation of the drying speed in an environment of high relative humidity, however, yields homogeneous NP deposition in the case of bimodal SiO2 and bimodal gold NP’s. In contrast, a sample of bipyramidal TiO2, heavily agglomerated when commonly dried, is successfully dispersed by spin coating the suspension on the substrate.
The analysis of the particle size distribution of the bimodal silica and gold samples yielded number ratios resembling the nominal number ratios. The reliable measurement of the NP concentration of polydisperse samples by electron microscopy, even if relative, is new and of special relevance because up to now only the size of the particles, i.e. the abscissa of the PSD, can be measured reliably.
T2 - EMPIR nPSize Training Course "Metrology for Measurement of Nanoparticle Size by Electron Microscopy and Atomic Force Microscopy"
CY - Online meeting
DA - 27.10.2020
KW - Nanoparticles
KW - Particle size distribution
KW - Sample peparation
KW - Electron microscopy
PY - 2020
AN - OPUS4-51716
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
T1 - Numerical modelling of compression stress relaxation and compression set of elastomer O-rings during aging
N2 - Elastomer seals are used in many industrial applications due to their excellent mechanical properties at a wide range of temperatures. Their high versatility and recovery potential under several load conditions make them well suitable for the application in containers designed for transport, storage and/or disposal of radioactive materials. In containers for low and intermediate level radioactive waste, elastomer seals are used as barrier seals, and as auxiliary seals in storage and transportation casks (dual purpose casks) for heat generating radioactive waste, such as spent fuel and high-level waste. While a seal exchange at defined intervals is typical in many conventional applications, it is impossible or at least hard to perform when principles of minimization of radiation exposure have to be considered and prohibit an unnecessary cask handling. An extensive knowledge of the change of the elastomer’s properties during aging and the availability of reliable end-of-lifetime criteria to guarantee the permanent safe enclosure of the radioactive material is mandatory. As BAM is involved in most of the national cask licensing procedures and in the evaluation of cask-related long-term safety issues, great efforts have been already made and are still planned to scientifically support this task.
Compression stress relaxation and compression set were identified as key indicators of elastomer long-term performance and quantitatively investigated in comprehensive test programs. Among other representative types of elastomers, specimens made from ethylene propylene diene rubber (EPDM) were tested before, during and after aging to capture the most important of their complex mechanical properties.
In the presented study, exemplary results were used to simulate the compression stress relaxation and the compression set of elastomer O-rings during aging. Regarding the influence of temperature, the time temperature superposition principle is applied in the relaxation analysis of elastomer O-rings. The proposed model is implemented in the commercial finite element software ABAQUS/Standard® [1] with a sequential temperature displacement coupling. Numerical results match the experimental compression stress relaxation measurements well. The prediction of compression set values after long-term aging shows a relatively good agreement with the experimental results. Nevertheless, all input parameters derived from the specimen tests, additional assumptions concerning boundary conditions and modeling strategy are discussed with regard to the identified slight discrepancies.
The possibility to extend the finite element model to represent the O-ring seal’s ability to recover after a (fast) partial release is taken into account
T2 - ASME 2020 Pressure Vessels & Piping Conference (PVP2020)
CY - Online meeting
DA - 03.08.2020
KW - Stress relaxation
KW - Ageing
KW - Compression Set
KW - O-ring
KW - Sequential analysis
KW - Simulation
PY - 2020
AN - OPUS4-52135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaunich, Matthias
T1 - Elastomer seals - overview and development
N2 - The talk summarizes the current and future investigations of elastomer seal materials in division 3.4.
T2 - IRSN-BAM Symposium Safety of Transport and Storage Packages
CY - Online meeting
DA - 19.11.2020
KW - Seal
KW - Degradation
KW - Ageing
PY - 2020
AN - OPUS4-51751
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heilmann, Maria
A1 - Hodoroaba, Vasile-Dan
T1 - Project 15 Measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension
N2 - The progress in the VAMAS Project #15" Measurement of particle size and shape distribution of bipyramidal titania including deposition from liquid suspension" within TWA 34 Nanoparticle Populations is presented with highlight of the following points:
- Determine and compare particle size and shape distribution by means of:
• electron microscopy (SEM, TEM, STEM-in-SEM)
• atomic force microscopy (AFM)
• small angle X-ray scattering (SAXS)
- Determine uncertainty induced by deposition protocol from liquid suspension with comparison to known values from a prior ILC with already deposited nanoparticles on TEM grids.
- Provide comparative validation of protocols for the techniques other than TEM.
T2 - VAMAS Regional Workshop 2023
CY - Online meeting
DA - 24.01.2023
KW - Nanoparticles
KW - VAMAS
KW - Electron microscopy
KW - AFM
KW - SAXS
KW - TiO2
PY - 2023
UR - https://www.bam.de/Content/EN/Events/2023/2023-01-24-vamas-regional-workshop.html
AN - OPUS4-57220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Morphological Analysis of Graphene Oxide by SEM and Correlative Field-Flow Fractionation Coupled with Multi-Angle Light Scattering
N2 - Since the first free-standing monolayer graphene sheet was successfully prepared in 2004 [1], graphene and graphene oxide materials achieved the necessary technical readiness level to be considered for use in commercial products. Moreover, the focus has shifted from fundamental research towards expanding the applicability of graphene-related 2D materials (GR2M) and to improve their competitiveness with established materials [2]. Significant advances have been made especially in applications regarding optoelectronics, energy storage materials, chemical additives, sensor applications etc. [3]. Composite products containing graphene and functionalized graphene such as inks and dyes have shown enhanced performance regarding longevity, wettability, and can be tailored for specific purposes through dedicated functionalization.
For accurate physico-chemical characterization, GR2M products in their raw form or as part of composites present challenges in terms of sample preparation, choice of analytical method and evaluation of data. For instance, in the context of imaging, these challenges encompass: (a) the selection of images magnifications being representative for all the flakes ranging in size from hundreds of nanometers to micrometers; (b) the selection of representative flakes for adequate statistics, which may involve the separation of overlapping/agglomerating flakes by segmentation; and (c) the classification of diverse morphologies such as irregularly shaped/crumpled flakes, porous flakes and particulate features present in the sample. The complexity of the analytical task has needed the introduction of specific ontology for 2D materials to identify the proper descriptors characterizing confidently the morphological features of interest. Regarding light scattering techniques such as Dynamic Light Scattering (DLS) and Multi-Angle Light Scattering (MALS) commonly used for process control in industry as a first measure, an alternative approach would be necessary. This is in part due to the use of the standard sphere-model for 2D materials as appearing to be inappropriate, whilst a disc-shape model potentially yields more suitable results. Standardization efforts are underway to establish a baseline for accurate characterization of aimed measurands with sufficient statistics. To date, the measurement methods recommended by standardization bodies for the morphological-structural characterization of GR2M’s are AFM, Raman Spectroscopy and SEM and/or TEM. The acquisition of statistically relevant numbers of flakes for a thorough characterization using TEM and AFM is particularly time-consuming.
The size distribution of graphene oxide- and graphene-containing inks was investigated by using a correlative approach coupling Centrifugal Field-Flow Fractionation (CF3) [4] with MALS. Up to now, promising results for Field-Flow Fractionation have been achieved only with respect to the separation into size classes of GO samples as well as of graphene oxide mixed with graphene by Asymmetrical Field-Flow Fractionation (AF4) [5], [6]. Besides the online characterization by MALS, the eluting size fractions obtained by CF3 were also collected and subsequently measured by SEM. Successful separation into size fractions allows us to apply ensemble techniques such as MALS to samples that were previously not measurable according to best-practices. In this study, the following material sub-classes have been observed with SEM: (i) nano-graphite mixed with graphene flakes, (ii) graphene oxide few- and multi-layer flakes with diverse and highly complex morphology, and (iii) graphene oxide of well-defined size and shape with >95% single- and bilayer content were investigated. Data on the class size ranges was obtained by MALS after separation with CF3 and consideration of a disc-shape model. Significant effort was invested into the sample preparation for CF3 measurements to achieve a recovery rate of >80%, well above the recommended 70% by ISO/TS 21362:2018 for validation purposes. The material fractions collected after the CF3 measurement were separately deposited on a silicon wafer and the size results of the SEM analysis were correlated with the corresponding mean sizes obtained with MALS.
T2 - Microscopy and Microanalysis 2025
CY - Salt Lake City, UTAH, USA
DA - 27.07.2025
KW - Advanced Material
KW - CF3
KW - SEM
KW - Morphology
PY - 2025
AN - OPUS4-64084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative chemical imaging to reveal the nature of different commercial graphene materials
N2 - Different synthesis techniques were developed which led to other graphene-related materials such as graphene oxide (GO) or elemental-doped graphene. Further chemical functionalization can enhance but also alter or reduce specific properties of the graphene. To reveal the nature of these materials a proper physico‑chemical characterization with different analytical techniques is crucial.
Single-layer GO flakes provided by Graphenea (Spain) were prepared for systematic image analysis. These flakes were disposed on an alignment-marked SiO2 substrate and correlatively imaged by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Raman spectroscopy. The high lateral resolution and/ or extreme surface sensitivity of the mentioned techniques is necessary to explore monolayers. The ToF-SIMS images match well with the SEM and AFM images and provide information about the chemistry. With 2D Raman spectroscopy it is possible to differentiate between the number of stacked single-layer flakes. This is visualized in a 3D image. Well-defined GO flakes could be used as a reference material for imaging of graphene-like structures but also of other types of 2D materials.
In addition to these monolayer GO flakes, commercial graphene-containing inks (Haydale) with a more complex morphology were also correlatively imaged. ToF-SIMS and SEM images were merged to identify the origin of different chemical fragments. The findings correlate closely with the expectation that the specific functionalizations (with fluorine and nitrogen as marker elements) are present only on the graphene flakes as presumed from the SEM images. Energy-dispersive X-ray spectroscopy (EDX) supports these results, yet with a much lower sensitivity compared to ToF-SIMS.
T2 - Joint Regulatory Risk Assessors Summit – Advancing Safety & Sustainability Assessments of Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - ToF-SIMS
KW - Imaging
KW - Graphene-related 2D materials
KW - SEM/EDX
KW - Auger electron spectroscopy
KW - Raman spectroscopy
PY - 2025
UR - https://macrame-project.eu/macrame-meetings-workshops/jointrras/#Agenda
AN - OPUS4-63656
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Reliable analysis of the elemental composition of graphene oxide flakes with energy dispersive spectroscopy (SEM/EDS) and x-ray photoelectron spectroscopy (XPS)
N2 - Suspensions of graphene-related 2D materials (GR2M) are broadly used for further applications like printable electronics. The reliable quantification of the composition of graphene-related 2D materials as liquid suspensions is still a challenging task, which can hinder the commercialisation of the products. Specific parameters to be measured are defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present [1], but reference protocols are still missing. One of the central methods for the quantification is X-ray photoelectron spectroscopy (XPS) as a rather expensive method. Therefore, the development of cheaper alternatives is highly desired. One attractive alternative of XPS is energy-dispersive spectroscopy (EDS) which is usually coupled with scanning electron microscopy (SEM). This combination is one of the most widely used methods in analytical laboratories. In this contribution the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material [2] are presented. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis [3], which has been carried out on the same samples.
It is demonstrated that for samples prepared by drop-casting on a substrate, both surface-sensitive XPS analysis and bulk-characterising EDS result in very similar elemental composition of oxygen and carbon for thick spots. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. The last results clearly show the influence of the substrate on the analysis of the results and stressed out the importance of the sample preparation.
T2 - E-MRS Spring Meeting
CY - Strasbourg, France
DA - 26.05.2025
KW - Graphene oxide
KW - Reliable Analysis
KW - Ionic Liquid
KW - Reference Material
PY - 2025
AN - OPUS4-63336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
A1 - Weber, Mike
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Simulation of compression set of epdm o-rings during aging
N2 - It is common practice in the application of finite element analysis to model compression set (CS) of elastomers during aging with two different material models according to the two-network theory of Tobolsky. The theory relies on the existence of two networks. The first one represents the original network after vulcanization and is sensitive to chain scission. The second network accounts for the formation of additional crosslinking during aging. Besides the use of user subroutines to describe the two-network model, an element overlay technique is also needed as the full set of both material behaviors did not exist for assignment to a single element. This element overlay technique is valuable for research and developmental purposes but makes extension to industrial usage quite challenging. Our goal is to simulate the CS of elastomers after long-term aging in a commercial finite element software with no need for extra subroutine codes or mesh superposition.
Ethylene propylene diene (EPDM) O-rings were aged in a compressed state at 75 °C, 100 °C, 125 °C and 150 °C for up to 183 days. Investigations of the experimental test results were used to identify material models and their parameters to develop a finite element model to simulate CS. The model was implemented in the finite element software ABAQUS/Standard® with a sequential temperature-displacement coupling.
Regarding the influence of temperature, the Arrhenius equation is adopted for the time-temperature relationship. The activation energy value that is required for the simulation is firstly determined from shifting the experimental CS results with the time-temperature superposition technique and plotting the shift factors in an Arrhenius diagram. The experiments were compared with the simulation results. Afterwards different activation energies were used in the simulation and discussed. A suitable choice of the activation energy value with regard to the reference temperature and the test temperature is presented. With the chosen activation energies, the match between numerical CS values after long-term aging and the experimental results was improved.
T2 - ASME 2022 Pressure Vessels & Piping Conference
CY - Las Vegas, USA
DA - 17.07.2022
KW - Simulation
KW - Compression set
KW - EPDM
KW - Aging
PY - 2022
SP - 1
EP - 9
AN - OPUS4-57370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
A1 - Hörenz, Christoph
T1 - Improving nanoparticle size measurement accuracy for safety assessment
N2 - Nanomaterials and nanoparticles are finding applications across a wide range of technology sectors, from medicine and food to transportation and construction. In order to assess these new materials for potential risks to health and the environment, they need to be well-characterised. The measurement of constituent nanoparticle size, shape, and size distribution are important factors for the risk evaluation process.
EMPIR project Improved traceability chain of nanoparticle size measurements (17NRM04, nPSize) is working to assess a range of traceable nanoparticle measurement approaches, including Scanning Electron Microscopy (also in Transmission Mode), Atomic Force Microscopy and Small Angle X-ray Scattering, and deliver improved calibration methods to users. For the techniques under investigation, physical models of their response to a range of nanoparticle types are developed. Validated reference materials will also be used for an inter-comparison of measurement systems, with an evaluation of the associated measurement uncertainty. With project contributions to standards development work, manufacturers will be better placed to assess the human and environmental risks posed by nanomaterials across a whole range of products.
KW - Nanoparticles
KW - Particle size distribution
KW - Traceability
KW - Electron microscopy
KW - AFM
KW - SAXS
PY - 2021
UR - https://www.euramet.org/?L=0&news=40%3A1159
SP - 1
PB - EURAMET e.V.
CY - Braunschweig
AN - OPUS4-52129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Nanoparticle size, shape, and concentration measurement at once – two VAMAS pre-standardization projects ready to start
N2 - A case study on the TEM analysis of the size and shape distribution of TiO2 bipyramidal nanoparticles prepared on TEM grids was included in the recently published ISO standard ISO 21363. It was agreed to organize at a later stage a second inter-lab comparison with the nanoparticles distributed to the participants as a liquid suspension. Protocols for uniform nanoparticle deposition on suited supports developed and optimized within the EMPIR nPSize project are also prepared to be distributed. For this, we have chosen the VAMAS platform (www.vamas.org) which offers an excellent international infrastructure of laboratories with high competence in nanoparticle measurement. The VAMAS technical working area dedicated to nanoparticle measurement is TWA 34 ‘Nanoparticle populations’. For this type of nanoparticles, the size and shape distributions are the primary parameters to be reported. Due to the good deposition protocols developed, an automated image analysis is enabled (in contrast to the manual analysis of irregular TiO2 nanoparticles.
In parallel with the TiO2 nanoparticle exercise, two spherical SiO2 nanoparticle samples with bi-modal size distributions (nominal relative number concentrations of 1:1 and 10:1) are prepared for a second VAMAS inter-lab comparison. Here, the nanoparticle concentration is the primary parameter to be measured. For the imaging methods it is targeted to measure the relative nanoparticle concentrations of the two modes. For the absolute nanoparticle concentration to be measured by imaging methods it is necessary to control the volume of the liquid suspension deposited on the substrate and to obtain such a homogeneous nanoparticle deposition on the substrate which allows to count (or extrapolate) all the deposited particles.
T2 - Microscopy and Microanalysis 2021
CY - Online meeting
DA - 01.08.2021
KW - Nanoparticles
KW - Electron microscopy
KW - VAMAS
KW - Inter-laboratory comparison
KW - TiO2
KW - SiO2
PY - 2021
AN - OPUS4-53065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison report from VAMAS/TWA 37 Quantitative Microstructural Analysis to ISO/TC 202 Microbeam Analysis
N2 - The liaison between VAMAS/TWA 37 Quantitative Microstructural Analysis and other TWAs to ISO/TC 202 Microbeam Analysis since the last Annual Meeting of ISO/TC 202 is reported. The VAMAS/TWA 37 projects initiated in the last year and the new ones in the planing phase are highlighted with technical and organisational details. Also need for more participants in 2 projects is discussed.
T2 - 32nd Plenary Meeting of ISO/TC 202 Microbeam Analysis
CY - London, United Kingdom
DA - 28.10.2025
KW - VAMAS
KW - Quantitative microstructural analysis
KW - ISO
KW - Standardisation
KW - Interlaboratory comparisons
PY - 2025
AN - OPUS4-64552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chemello, Giovanni
T1 - Characterization of Graphene using HAXPES
N2 - Since its discovery, graphene has got growing attention in the industrial and application research due to its unique properties . However, graphene has not been yet implemented into the industrial market, in particularly due to the difficulty of properly characterizing this challenging material. As most of other nanomaterials, graphene’s properties are closely linked to its chemical and structural properties, such as number of layers, flake thickness, degree of functionalisation and C/O ratio. For the commercialization, suitable procedures for the measurement and characterization of the ultrathin flakes, of lateral dimensions in the range from µm to tens of µm, are essential.Surface chemical methods, especially XPS, have an outstanding role of providing chemical information on the composition. Thereby, one well-known problem for surface analytical methods is the influence of contamination on the composition as in the case of adventitious carbon. The differentiation between carbon originated from the contamination or from the graphene sample itself is often not obvious, which can lead to altered results in the determination of the composition. To overcome this problem, Hard Energy X-ray Photoelectron Spectroscopy (HAXPES) offers new possibilities due to its higher information depth. Therefore, XPS measurement obtained with Al Kα radiation (E = 1486. 6 eV) were compared with analyses performed with a Cr Kα (E = 5414. 8 eV) excitation on functionalized graphene samples. Differences are discussed in terms of potential carbon contamination, but also of oxygen on the composition of the samples. Measurements are performed on O-, N- and F-functionalized graphene. Different preparation procedures (powder, pellet, drop cast from liquid suspension) will be also discussed, correlation of the results with the flakes morphology as well as their validation with other independent methods are in progress.
T2 - ECASIA 2022
CY - Limerick, Ireland
DA - 29.05.2022
KW - Graphene
KW - Functionalized graphene
KW - Depth profiling
PY - 2022
AN - OPUS4-56814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Chemical and structural changes at the surface of titanium materials upon irradiation with near-infrared ultrashort laser pulses
N2 - Due to its large strength-to-weight ratio and excellent biocompatibility, titanium materials are of paramount importance for medical applications, e.g. as implant material for protheses. In this work, the evolution of various types of laser-induced micro- and nanostructures emerging on titanium or titanium alloys upon irradiation by near-infrared ultrashort laser pulses (925 fs, 1030 nm) in air environment is studied for various laser fluence levels, effective number of pulses and at different pulse repetition rates (1 – 400 kHz). The morphologies of the processed surfaces were systematically characterized by optical and scanning electron microscopy (OM, SEM). Complementary white-light interference microscopy (WLIM) revealed the corresponding surface topographies. Chemical and structural changes were analysed through depth-profiling time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray diffraction (XRD) analyses. The results point towards a remarkable influence of the laser processing parameters on the surface topography, while simultaneously altering the near-surface chemistry via laser-induced oxidation effects. Consequences for medical applications are outlined.
T2 - E-MRS Spring Meeting 2022
CY - Online meeting
DA - 30.05.2022
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - ToF-SIMS
KW - Chemical analysis
KW - Titanium
PY - 2022
AN - OPUS4-54931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Kotil, Leyla
A1 - Matjacic, Lidija
A1 - McMahon, Greg
A1 - Bernicke, Michael
A1 - Bernsmeier, Denis
A1 - Kraehnert, Ralph
A1 - Hertwig, Andreas
A1 - Hodoroaba, Vasile-Dan
T1 - Morphological and Chemical Nanoscale Analysis of Mesoporous Mixed IrOx-TiOy Thin Films as Electrode Materials
N2 - orous films play an important role particularly in energy applications like photovoltaics, electrolysis or batteries. Thin film properties such as thickness, chemical composition, crystallinity of the framework, and porosity define the activity of the porous films. The accurate morpho-chemical characterisation of mesoporous thin films is a challenging analytical task which requires the consideration of new analytical approaches based on the combination of data of different methods able to address the structure and chemical composition at the nanoscale. In this contribution we characterise thin mesoporous iridium-titanium mixed oxide film properties by Electron Probe Microanalysis (EPMA) with Energy-Dispersive X-ray Spectroscopy (EDS) at an SEM applied in a dedicated “thin film analysis” approach (1). Thus, the film mass deposition, film thickness and the film density can be determined. Further, by dividing the measured film density to an assumed (theoretical) metal oxide framework (skeletal) density, the thin film porosity can be extracted, too.
In order to assess the homogeneity of the thin film properties like the chemical composition, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Auger Electron Spectrometry are applied in the depth profiling mode, so that possible in-depth gradients are detected. Lateral inhomogeneities in the chemical composition and structure of the thin mesoporous films are also identified by applying the same methods in the line-scan or mapping mode, which can be further combined with in-depth sputtering for 3D information. The role of the spatial resolution of the analytical methods considered, which can go down well below 100 nm, will be highlighted.
KW - Mesoporous thin films
KW - Imaging
KW - TiO2
KW - Ir oxid
KW - Auger electron spectroscopy
KW - ToF-SIMS
KW - SEM/EDX
PY - 2024
DO - https://doi.org/10.1093/mam/ozae044.252
VL - 30
IS - Supplement 1
SP - 541
EP - 542
PB - Oxford University Press (OUP)
AN - OPUS4-61185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - EMPIR nPSize - Improved Traceability Chain of Nanoparticle Size Measurement - What nPSize can offer to ISO/TC 229?
N2 - The main outcomes of the EMPIR project nPSize are presented and the suitability of the new capabilities, e.g. reference materials, sample preparation protocols, measurement procedures, and data analysis, to be standardized and implemented in accredited analytical laboratories is discussed. Complementation and/or filling gaps of published and ongoing standardisation projects on size, shape and number concentration measurements under ISO/TC 229/JWG 2 are offered.
The two VAMAS inter-laboratory comparisons resulted from the nSPize project and just started under TWA 34 Nanoparticle Populations (Projects #15 and #16) of bipyramidal TiO2 anatase and bimodal SiO2 nanoparticles are presented in detail.
T2 - Interim Meeting of ISO/TC 229 Nanotechnologies - Strategy and Metrology Group
CY - Online meeting
DA - 09.05.2022
KW - Nanoparticles
KW - Particle size distribution
KW - Inter-laboratory comparison
KW - Electron microscopy
KW - AFM
KW - SAXS
KW - ISO/TC229
PY - 2022
AN - OPUS4-54819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Analysis of Industrial Graphene-Based Flakes – First Results on Morphological Characterization, Sample Preparation and Chemical Composition
N2 - In order to bridge the gap between lab-scale and industrial-scale production of graphene it is necessary to develop processes, equipment and measurement procedures to control the material features. One of the crucial reasons of graphene’s limited commercialization is the lack of standard procedures to properly characterize and define the material chemical and structural properties down to the nanometer level. This leads to many issues regarding material synthesis repeatability, inappropriateness choice of measurands and measurement reproducibility which heavily affect the consistency of the material performance.
In our study, a comparative analysis is performed on two different series (G5 and G6) of industrial graphene powders, each series produced with four types of functionalization: raw graphene, oxygen-functionalized, nitrogen-functionalized and fluorine-functionalized. All the 8 sample variants were analyzed from a chemical and morphological point of view in the form of powders prepared as slightly pressed in metallic sample holders.
The results of the comparative chemical analyses XPS and EDS show a good agreement in the concentration values for all the elements present in the samples, despite the different analysis volumes addressed by the two techniques. For this reason, the samples can be considered homogeneous in both lateral and vertical direction.
A clear influence of the morphology on the composition is evident. Therefore, such correlative measurements of morphology and composition are necessary for a comprehensive characterization of industrial graphene flakes.
KW - Graphene powder
KW - XPS
KW - HAXPES
KW - SEM
KW - EDS
KW - Functionalized graphene
PY - 2022
DO - https://doi.org/10.1017/S1431927622004342
SN - 1435-8115
VL - 28
IS - Suppl 1
SP - 1006
EP - 1008
PB - Cambridge University Press
CY - New York, NY
AN - OPUS4-55512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - XPS of GR2M
N2 - The activities of ISO-G-Scope are presented. The influence of the sample preparation and the results of XPS/HAXPES measurements are discussed.
T2 - Graphene Workshop @ ISO TC 229 Meeting
CY - Teddington, UK
DA - 16.11.2022
KW - Graphene related materials
KW - X-ray photoelectron spectroscopy
KW - Sample preparation
KW - Hard X-ray photoelectron spectroscopy
PY - 2022
AN - OPUS4-56434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Knowledge Infrastructure supporting image-based characterisation of 2D graphene materials
N2 - To better understand the relationship between image features and biological effects such as toxicity,we have developed a method combining image thresholding and pixel-wise segmentation to create annotated datasets. These datasets are used to train machine learning models and establish human–AI learning loops for material classification and structure detection. We employ deep learning architectures such as ResNet, EfficientNet, and U-Net to automate the classification and segmentation of SEM/TEM images of 2D nanomaterials, with targeted manual annotation focusing on key structures (graphene flakes, agglomerates, contaminants, etc.). This approach ensures reproducible, large-scale analysis, which is essential for studying the links between structure and biological response. Finally, our methodology aligns with OECD requirements and contributes to the Safe and Sustainable by Design (SSbD) framework, aiming to enhance product reliability and sustainability.
T2 - Joint Regulatory Risk Assessors Summit – Advancing Safety & Sustainability Assessments of Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - Graphene
KW - 2D materials
KW - Knowledge infrastructure
KW - Imaging
KW - Machine learning
PY - 2025
UR - https://macrame-project.eu/macrame-meetings-workshops/jointrras/#Agenda
AN - OPUS4-63682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - How to measure the chemical composition of industrial graphene - New insights from an interlaboratory comparison
N2 - International standards describing reliable protocols will facilitate the commercialization of graphene and related 2D materials. One physico-chemical key property next to flake size and thickness is the chemical composition of the material. Therefore, an ISO standard is under development with X-ray photoelectron spectroscopy having a prominent role. With its information depth of around 10 nm which is the similar length scale as the thickness as of particles of 2D materials consisting of a few monolayer XPS seems to be highly suitable for this purpose. Different sample preparation methods like pressing the powders onto adhesive tapes, into recesses, or into solid pellets result in inconsistencies in the quantification. For the validation of the quantification with XPS an interlaboratory comparison was initiated under the auspice of the “Versailles Project on Advanced Materials and Standards” (VAMAS). First results confirm that the sample preparation method (pellet vs. powder) influences the quantification results clearly.
T2 - Characterization of Nanomaterials Colloquium
CY - Berlin, Germany
DA - 04.07.2023
KW - X-ray photoelectron spectroscopy
KW - Functionalized graphene
KW - Interlaboratory comparison
PY - 2023
AN - OPUS4-57897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaghdoudi, Maha
T1 - Analysis of heterogeneous ageing of hnbr o rings
N2 - Hydrogenated nitrile butadiene rubber (HNBR) elastomer was thermo-oxidatively aged at different temperatures up to 150°C. Fourier transform infrared spectroscopy (FTIR), compression stress relaxation (CSR) and IRHD microhardness were used to characterise the chemo-mechanical changes of HNBR O-rings during thermo-oxidative ageing. FTIR shows the development of carbonyl, methyl and ester groups but the nitrile content was not affected by ageing. The effect of sample geometry during CSR was investigated. CSR data were converted through integrated kinetic laws. The conversion has proven its sensibility to detect heterogeneous ageing. This was confirmed by the IRHD measurements across the section of O-rings. Oxidation profiles were determined by applying the model of Wise et al. to the IRHD experimental results.
T2 - The 2023 Postgraduate Seminar - Advanced Structured Materials
CY - Barcelona, Spain
DA - 20.02.2023
KW - HNBR
KW - Heterogeneous ageing
KW - IRHD
KW - FTIR
KW - CSR
PY - 2023
AN - OPUS4-57057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS Regional Report Germany 2024
N2 - Regional standardisation activities and how VAMAS can help in any way to promote activities are reported.
Activities related to organisational updates, government initiatives/priorities (especially related to Advanced Materials), details of any strategy documents publicly available, networks within Germany and how we engage are presented.
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 49th Steering Committee Meeting
CY - Rio de Janeiro, Brazil
DA - 23.09.2024
KW - VAMAS
KW - Advanced materials
KW - Standardisation
PY - 2024
UR - http://www.vamas.org/
AN - OPUS4-61405
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sachse, René
T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrO IrOxfilms revealed under realistic OER conditions
N2 - In the face of rising energy demand and the impending climate change the development of a sustainable, fossil-free fuel and chemical production is of global importance. One possible goal is the development of electrochemical conversion processes using catalysts. Porous materials play an important role in such energy applications. The activity and stability of each catalyst is highly dependent on the properties of the coating, i.e., phase composition, crystallinity, accessible surface area, and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physico-chemical properties. However, the complex morphology of such catalysts constitutes a challenge even for modern analytical techniques. Spectroscopic ellipsometry (SE) is a versatile method for studying material properties by using appropriate models (e.g., film thickness, optical and electronic properties). Ellipsometric models need to be validated in order to produce accurate results. In a first step, the model for the ellipsometric fit studies of a calcination series of mesoporous iridium oxide films (300 – 600 °C) was investigated and validated with respect to their material properties.[4] The information on electronic structure of the catalysts shows a direct correlation with electrochemical activities. The development of an environmental electrochemical cell offers the possibility of investigations under operando conditions. Thus, changes in optical and electronic properties can be induced and monitored during the electrocatalytic oxygen evolution reaction.
T2 - 9th International Conference on Spectroscopic Ellipsometry
CY - Beijing, China
DA - 22.05.2022
KW - Mesoporous iridium oxide films
KW - Non-destructive operando analysis
KW - Oxygen evolution reaction
KW - Spectroscopic ellipsometry
PY - 2022
AN - OPUS4-54915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaunich, Matthias
T1 - Low temperature properties of rubber seals
N2 - Understanding the failure mechanisms that lead to leakage of rubber seals at low temperatures is important. Rubber properties are highly temperature dependent. Changes in behaviour at low temperatures can result from the rubber-glass transition and for some rubbers by partial crystallisation. Experimental results on the low temperature behaviour of different rubber seals were discussed to help understand seal failure processes.
T2 - Rubber in Engineering Group (RIEG) webinar an Elastomers at Low Temperatures
CY - Online meeting
DA - 11.09.2020
KW - Low temperature
KW - Rubber seal
KW - Compression set
KW - Glass transition
PY - 2020
UR - https://www.iom3.org/rubber-engineering-group/event/elastomers-low-temperatures
AN - OPUS4-51306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sachse, René
T1 - Operando electrochemical spectroscopic ellipsometry: Material properties of highly active mesoporous IrO IrOxfilms revealed under realistic OER conditions
N2 - Rising energy demand and the impending climate change require the development of a sustainable, fossil-free fuel and chemical production on a global scale. Hydrogen production via water electrolysis will be a fundamental cornerstone in this endeavor. The activity and stability of respective electrode coatings strongly depends on the coating's properties, i.e. phase composition, crystallinity, electrical conductivity, accessible surface, wettability and many other factors. The key to the development of improved catalysts is a better understanding of the relations between their performance, stability and physicochemical properties. However, those relations can be complex, and are strongly influenced also by the reaction environment. Hence, operando analysis of the catalyst material during catalysis at realistic potentials and current densities is highly desirable. Yet, many analytical techniques cannot be applied in liquid environments at realistic potentials and current densities.
We propose environmental ellipsometric analysis in a dedicated electrochemical flow cell as a new method to evaluate gas evolution reactions operando under realistic working conditions. Figure 1 illustrates schematically the developed technique. Key factors to success are highly active model-type catalysts with template-controlled porosity, a suitable sample environment, a deep understanding of the spectroscopic method and respective model development, as well as concise cross validation with numerous other analytical techniques.
The method was developed and validated by analyzing a calcination series (300 - 600°C) of mesoporous templated IrOx films ex-situ and operando under oxygen evolution reaction (OER) conditions. The employed environmental electrochemical spectroscopic ellipsometric analysis (ECSE) revealed during OER the change of optical and electronic properties, i.e. the dielectric functions (real ε1 and imaginary part ε2), electrical and electronic properties such as resistivity (ρ) and band-to-band transitions (p-d band transitions). Film thickness and porosity were validated by means of scanning electron microscopy (SEM), X-ray reflectometry (XRR) or ellipsometric porosimetry (EP), electrical and electronic properties by means of conductivity measurements, X-ray photoelectron spectroscopy (XPS) or UV-Vis-NIR absorption spectroscopy. The electronic structures of the catalysts from valence electron energy loss spectra (VEELS) derived from the real (ε1) and imaginary part (ε2) of the dielectric function from SE measurements reveal a direct correlation with electrochemical activities in OER.
In the presentation reversible and irreversible potential-dependent changes of the catalyst properties during operation will be discussed along with the dynamics of gas formation, transport and dissolution
T2 - E MRS 2021 SPRING MEETING
CY - Online meeting
DA - 31.05.2021
KW - Spectroscopic ellipsometry
KW - Ectrocatalysis
KW - Oxygen evolution reaction
KW - Mesoporous iridium oxide films
KW - Non-destructive operando analysis
PY - 2021
AN - OPUS4-52929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - In depth analysis of commercial functionalized graphene nanoplateles towards structure-activity relationships
N2 - The analysis of commercial graphene related products from the raw material to inks is discussed and the input to structure-activity relationships. Different approaches to obtain structure-activity relationships like operando or using data mining are presented. Challenges and recommendation to obtain structure-activity relationships are given.
T2 - Joint Regulator Risk Summit: Advancing Safety & Sustainability Assessments of Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - Functionalized graphene
KW - Structure activity relationsships
KW - Commercialisation
PY - 2025
AN - OPUS4-63565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Surface Analysis and Context of the New HAXPES@BAM
N2 - The Competence Centre nano@BAM is presenting a new X-ray Photoelectron Spectrometer – the HAXPES (XPS at hard energy) – for researching advanced materials at the nanoscale. With HAXPES detailed chemical information can now be gained not only from the first outermost nanometres of the sample surface, but also from deeper regions.
Top international experts will share their knowledge and key findings on how to utilise HAXPES for exploring the surface of various advanced materials. Following the lectures, we will show you a short demo of the new instrument and answer your questions.
T2 - Inauguration of the HAXPES@BAM - A new Hard-X-Ray Photoelectron Spectrometer
CY - Online meeting
DA - 25.01.2022
KW - XPS
KW - HAXPES
KW - Nano@BAM
KW - Surface Analysis
PY - 2022
UR - https://www.bam.de/Content/EN/Events/2022/2022-01-25-hapex.html
AN - OPUS4-54377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - Chemical analyses of ps-laser generated LIPSS and Spikes on titanium alloy by HAXPES, XPS, and depth-profiling TOF-SIMS
N2 - Laser-induced periodic surface structures (LIPSS) and their combination with self-ordered microstructures forming hierarchical Spikes enable a large variety of different surface functionalizations for applications in the fields of optics, fluidics, tribology, or medicine. Moreover, high spatial frequency LIPSS (HSFL) provide an appealing and straightforward way for surface nanostructuring featuring spatial periods even below 100 nm – far beyond the optical diffraction limit. However, the imposed surface functionalities are usually caused by both, topographic and chemical surface alterations. For exploring these effects in detail, multi-method characterizations were performed here for HSFL and hierarchical Spikes processed on Ti-6Al-4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ~1 ps pulse duration, 1 – 400 kHz pulse repetition rate) under different laser and scan processing conditions. The following sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), stylus profilometry (SP), and white light interference microscopy (WLIM), as well as near-surface chemical analyses by X-ray photoelectron spectroscopy (XPS), hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results allow to qualify the laser ablation depth, the geometrical HSFL/Spikes characteristics and provide detailed insights into the depth extent and the nature of the ps-laser-induced near-surface oxidation arising from the laser-processing in ambient air and into the relevance of heat-accumulation effects at high pulse repetition rates. Moreover, the direct comparison of the HAXPES and XPS data reveals the role of surface-covering organic contaminants adsorbed from the ambient atmosphere without the uncertainties and potential sputter reduction potentially caused by ion-sputter depth profiling.
T2 - 11th International LIPSS Workshop
CY - Madrid, Spain
DA - 27.09.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrafast laser processing
KW - Hard X-ray photoelectron spectroscopy (HAXPES)
KW - Time-of-flight secondary ion mass spectrometry (ToF-SIMS)
KW - Ti6Al4V alloy
PY - 2023
AN - OPUS4-58532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rossi, Andrea
A1 - Alladio, Eugenio
A1 - Drobne, Damjana
A1 - Hodoroaba, Vasile-Dan
A1 - Jurkschat, Kerstin
A1 - Kononenko, Veno
A1 - Madbouly, Loay Akmal
A1 - Mrkwitschka, Paul
A1 - Novak, Sara
A1 - Radnik, Jörg
A1 - Saje, Špela
A1 - Santalucia, Rosangela
A1 - Sordello, Fabrizio
A1 - Pellegrino, Francesco
T1 - Development of a one-pot synthesis of rGO in water by optimizing Tour’s method parameters
N2 - Since its first synthesis in 2004, graphene has been widely studied and several different synthesis methods has been developed. Solvent exfoliation of graphite and the reduction of graphene oxide previously obtained through graphite oxidation are the most employed. In this work, we exploited synthesis conditions of a method usually employed for obtaining graphene oxide (the Tour’s method) for directly obtaining a very poorly oxidised material with characteristics like reduced graphene oxide. For the first time, a one-pot synthesis of reduced graphene oxide (rGO) is reported avoiding the use of a post-synthesis chemical or thermal reduction of the graphene oxide that requires further reagents, heat and time.
KW - Graphene
KW - 2D-materials
KW - Tour's method
KW - rGO
KW - One-pot synthesis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611827
DO - https://doi.org/10.1038/s41598-024-73606-2
SN - 2045-2322
VL - 14
SP - 1
EP - 10
PB - Springer Nature
CY - London
AN - OPUS4-61182
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Amelie
A1 - Tentschert, Jutta
A1 - Pieters, Raymond
A1 - Bennet, Francesca
A1 - Dirven, Hubert
A1 - van den Berg, Annemijne
A1 - Lenssen, Esther
A1 - Rietdijk, Maartje
A1 - Broßell, Dirk
A1 - Haase, Andrea
T1 - Towards a risk assessment framework for micro- and nanoplastic particles for human health
N2 - Background
Human exposure to micro- and nanoplastic particles (MNPs) is inevitable but human health risk assessment remains challenging for several reasons. MNPs are complex mixtures of particles derived from different polymer types, which may contain plenty of additives and/or contaminants. MNPs cover broad size distributions and often have irregular shapes and morphologies. Moreover, several of their properties change over time due to aging/ weathering. Case-by-case assessment of each MNP type does not seem feasible, more straightforward methodologies are needed. However, conceptual approaches for human health risk assessment are rare, reliable methods for exposure and hazard assessment are largely missing, and meaningful data is scarce.
Methods
Here we reviewed the state-of-the-art concerning risk assessment of chemicals with a specific focus on polymers as well as on (nano-)particles and fibres. For this purpose, we broadly screened relevant knowledge including guidance documents, standards, scientific publications, publicly available reports. We identified several suitable concepts such as: (i) polymers of low concern (PLC), (ii) poorly soluble low toxicity particles (PSLT) and (iii) fibre pathogenicity paradigm (FPP). We also aimed to identify promising methods, which may serve as a reasonable starting point for a test strategy.
Results and conclusion
Here, we propose a state-of-the-art modular risk assessment framework for MNPs, focusing primarily on inhalation as a key exposure route for humans that combines several integrated approaches to testing and assessment (IATAs). The framework starts with basic physicochemical characterisation (step 1), followed by assessing the potential for inhalative exposure (step 2) and includes several modules for toxicological assessment (step 3). We provide guidance on how to apply the framework and suggest suitable methods for characterization of physicochemical properties, exposure and hazard assessment. We put special emphasis on new approach methodologies (NAMs) and included grouping, where adequate. The framework has been improved in several iterative cycles by taking into account expert feedback and is currently being tested in several case studies. Overall, it can be regarded as an important step forward to tackle human health risk assessment.
KW - Microplastics
KW - Nanoplastics
KW - Human health
KW - Risk assessment
KW - Integrated approaches to testing and assessment (IATAs)
KW - Polymers of low concern (PLC)
KW - Poorly soluble low toxicity particles (PSLT)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623790
DO - https://doi.org/10.1186/s12989-024-00602-9
SN - 1743-8977
VL - 21
IS - 1
SP - 1
EP - 21
PB - Springer Science and Business Media LLC
AN - OPUS4-62379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vega Puga, E.
A1 - Wachtendorf, Volker
A1 - Kömmling, Anja
A1 - Brendelberger, S.
A1 - Jaunich, Matthias
A1 - Sattler, C.
T1 - Lifetime prediction and degradation assessment of FKM and FFKM O-rings under high temperature thermo-oxidative ageing
N2 - To support the development of solar reactor technologies for hydrogen production, this study investigates the thermo-oxidative degradation mechanisms of fluorinated elastomers and predicts their lifetimes at high temperatures (200–300 ◦C) consistent with the application requirements. An accelerated ageing programme is conducted with FKM and FFKM O-rings and flat samples for up to 21 days. Optical microscopy is used to analyse the exposed seals’ morphological changes, while IR microscopy is utilised to investigate the underlying chemical degradation mechanisms of both elastomers. Findings suggest that FKM’s degradation arises from dehydrofluorination of the polymer, followed by chain scission and backbone cleavage as a result of the oxidation of newly formed C=C double bonds. FFKM’s degradation is primarily associated with chain scission, but there is also indication that post-curing processes may occur during material ageing. Furthermore, hardness, equilibrium compression set (CS), continuous compression stress relaxation (CSR) and leakage rate tests are used to evaluate changes in the mechanical properties and sealing performance of the elastomers. Equilibrium CS data is extrapolated using time-temperature shifts (TTS) and used to derive an end-of-life criterion of 75 % equilibrium CS, which correlates to leakage rates higher than a predetermined threshold. Service lifetime predictions of FKM and FFKM O-rings at several temperatures are performed and a seal operating temperature of 200 ◦C is suggested, which ensures reasonable O-ring replacement intervals of more than half a year in the solar reactor for both considered materials.
KW - Fluoroelastomer
KW - Perfluoroelastomer
KW - Thermo-oxidative ageing
KW - Lifetime prediction
KW - Compression set
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630112
DO - https://doi.org/10.1016/j.polymertesting.2025.108820
SN - 1873-2348
VL - 147
SP - 1
EP - 17
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Despotelis, Konstantinos
A1 - Paton, Keith
A1 - Clifford, Charles A
A1 - Pollard, Andrew
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Approaches for the measurement of lateral dimensions of graphene oxide flakes using scanning electron microscopy
N2 - There is a practical need, especially from the industrial community, to accurately measure the size and shape of graphene oxide (GO) flakes of commercial origin, in a reliable, simple, and unambiguous way. The sample preparation is a decisive step to obtain a homogeneous distribution of flakes on a substrate, which is suitable for image analysis. A certain level of inhomogeneity was still found but could be accepted for the purpose of this lateral size measurement study. A measurement procedure for Scanning Electron Microscopy (SEM) including sample preparation, measurement, image analysis and reporting was developed and validated to be applied for the lateral size analysis of “real-world” 2D flakes. Samples were produced for analysis by drop casting GO dispersions onto Si/SiO2 substrates. After SEM imaging, the images were analysed using two approaches to derive size and shape parameters. The influence of different operators has been evaluated. A maximum difference of 10% for the size descriptor and 2% for shape descriptor was found for both image analysis approaches when different samples of the same source material are measured and analysed by the same operator, hence indicating variability caused by sample preparation and analysing different sample areas. When different laboratories/operators perform the image analysis on exactly the same images and same flakes, the deviation found for the size descriptor is 2% and 4.6% corresponding to the two approaches applied, while no difference in the shape descriptor is observed.
KW - Graphene oxide
KW - SEM
KW - Lateral dimension
KW - Standardisation
KW - Imaging
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625070
DO - https://doi.org/10.1088/2632-959X/adae28
VL - 6
IS - 1
SP - 1
EP - 11
PB - IOP Publishing
AN - OPUS4-62507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madbouly, Loay Akmal
A1 - Mrkwitschka, Paul
A1 - Stockmann, Jörg Manfred
A1 - Jones, Elliot
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Comparative Elemental Analysis of Commercial Functionalized Graphene Nanoplatelets Along the Production Chain With X‐Ray Photoelectron and Energy‐Dispersive X‐Ray Spectroscopy
N2 - Graphene has been commercialized for over a decade, primarily in the form of suspensions and inks. In this study, we investigate the properties of graphene nanoplatelets (GNPs) and their functionalized derivatives, incorporating fluorine or nitrogen as functional groups (FG). The analysis was conducted on three forms, that is, powders, suspensions, and inks, using X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy‐dispersive X‐ray spectroscopy (EDX). The objective of this work is to establish a rapid and comprehensive systematic approach for elemental analysis of commercial functionalized graphene, which can be used for quality control. Functionalization is employed to tailor the material's physical and chemical properties. In our study, graphene samples, functionalized with fluorine or ammonia in a plasma reactor, were investigated. Both XPS and EDX were applicable for all three forms and showed, in general, similar trends between the three forms, so that both XPS and EDX can be used for quality control of GNPs along the production chain.
KW - Commercial graphene
KW - Functionalized graphene
KW - Graphene inks
KW - SEM/EDS
KW - XPS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625752
DO - https://doi.org/10.1002/sia.7386
SN - 1096-9918
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-62575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - John, Elisabeth
A1 - Weise, Matthias
A1 - Radnik, Jörg
A1 - Stockmann, Jörg Manfred
A1 - Lange, Thorid
A1 - Sahre, Mario
A1 - Hodoroaba, Vasile-Dan
T1 - Towards a New Reference Material—Analytical Challenges in Examining High-Entropy Alloy Thin Films
N2 - A new high-entropy alloy (HEA) consisting of titanium, chromium, manganese, iron, and nickel was deposited as a thin-film on silicon substrates using magnetron sputtering from a novel segmented target composed of metal stripes. This material was explored with the goal to create a new reference material for surface analysis and evaluation of complex composite materials. The film's morphology was initially characterized by scanning electron microscopy (SEM), followed by crystallographic analysis using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The two-dimensional compositional homogeneity was assessed using a combination of scanning and transmission electron microscopy (TEM) with energy-dispersive spectroscopy (EDS), X-ray fluorescence (XRF), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and X-ray photoelectron spectroscopy (XPS). The in-depth chemical composition was further analysed using ToF-SIMS and Auger electron spectroscopy (AES). Our findings demonstrate that it is possible to produce thin HEA films with a homogeneous in-depth composition from a segmented target. Notably, despite the fixed composition of the target, we were able to vary the HEA's composition by exploiting inhomogeneities within the magnetrons sputter plasma. Additionally, we successfully created HEA films with significant compositional gradients.
T2 - ECASIA
CY - Gothenburg, Sweden
DA - 10.06.2024
KW - Reference material
KW - High-entropy alloy
KW - Thin-films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625777
DO - https://doi.org/10.1002/sia.7387
SN - 1096-9918
SP - 1
EP - 8
PB - Wiley
AN - OPUS4-62577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Comparative study of suitable preparation methods to evaluate irregular shaped, polydisperse nanoparticles by scanning electron microscopy (SEM).
N2 - Reliable characterization of materials at the nanoscale regarding their physio-chemical properties is a challenging task, which is important when utilizing and designing nanoscale materials. Nanoscale materials pose a potential toxicological hazard to the environment and the human body. For this reason, the European Commission amended the REACH Regulation in 2018 to govern the classification of nanomaterials, relying on number-based distribution of the particle size.
Suitable methods exist for the granulometric characterization of monodisperse and ideally shaped nanoparticles. However, the evaluation of commercially available nanoscale powders is problematic. These powders tend to agglomerate, show a wide particle size distribution and are of irregular particle shape.
Zinc oxide, aluminum oxide and cerium oxide with particle sizes less than 100 nm were selected for the studies and different preparation methods were used comparatively.
First, the nanoparticles were dispersed in different dispersants and prepared on TEM-supported copper grids. Furthermore, individual powders were deposited on carbon-based self-adhesive pads. In addition, the samples were embedded by hot mounting and then ground and polished.
The prepared samples were investigated by scanning electron microscopy (including the transmission mode STEM-in-SEM) and Dynamic Light scattering. The software package ImageJ was used to segment the SEM images and obtain the particle sizes and shapes and finally the number-based particles size distribution with size expressed as various descriptors.
T2 - Ceramics 2021
CY - Online meeting
DA - 19.04.2021
KW - Nanoparticles
KW - Preparation
KW - Characterization
PY - 2021
AN - OPUS4-53272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Perspective of BAM on Advanced Materials
N2 - A brief perspective of BAM on advanced materials is presented including examples for nanomaterials and other systems presenting advanced materials with special emphasis on characterization methods used in different division of BAM for the determination of functional or safety parameters of such materials. In this respect, also ongoing activities of the capacity building project nanoplatform of BAM aiming at the development of nanometer-sized reference materials are briefly summarized.
T2 - BfR Workshop zu Advanced Materials
CY - Online meeting
DA - 04.11.2020
KW - Quality assurance
KW - Risk assessment
KW - Safety
KW - Core/shell particle
KW - Characterization
KW - Measurement uncertainty
KW - Method
KW - Nano particle
PY - 2020
AN - OPUS4-51620
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Fine iron oxide nanoparticles as a candidate reference material for reliable measurement of particle size
N2 - Background, Motivation and Objective
Nanomaterials are at the core of some of the 21st century’s most promising technologies. In order to utilize and rationally design materials at the nanoscale the reliable characterization of their physico-chemical properties is highly important. Furthermore, the European Commission has taken measures via the REACH Regulations to control the classification of nanomaterials. REACH Annexes which entered into force in January 2020 require manufacturers to register nanomaterials that are traded in larger quantities (at least 1 ton). Every powder or dispersion where 50% (number distribution) of the constituent particles have sizes ≤ 100 nm in at least one dimension are defined as a nanomaterial. This creates a need for both industrial manufacturers and research and analytical service facilities to reliably characterize potential nanomaterials. Currently, BAM is working on developing reference nanoparticles, which shall expand the scarce list of worldwide available nano reference materials certified for particle size distribution, but also targeting other key parameters such as shape, structure (including porosity) and functional properties. Thus, candidate materials are considered to complement the already available spherical and monodisperse silica, Au and polystyrene reference nanoparticles, e.g. iron oxide and titanium oxide, with an average atomic number between those of silica and gold. Particularly for the imaging by electron microscopies, new nanoparticles of well-defined size in the range of 10 nm are decisive for the accurate particle segmentation by setting precise thresholds.
Statement of Contribution/Methods
Synthesis: Highly monodisperse iron oxide nanoparticles can be synthesized in large quantities by thermal decomposition of iron oleate or iron acetylacetonate precursors in high boiling solvents such as octadecene or dioctyl ether in the presence of oleic acid and oleylamine as capping agents.
Scanning Electron Microscope: An SEM of type Supra 40 from Zeiss has been used including the dedicated measurement mode transmission in SEM (STEM-in-SEM) with a superior material contrast for the nanoparticle analysis. The software package ImageJ has been used for the analysis of the STEM-in-SEM images and to determine the particle size distribution.
Dynamic Light scattering (DLS): Particles in suspension were measured in comparison by means of Zetasizer Nano (Malvern Panalytical; cumulants analysis) and NanoFlex (Microtrac; frequency power spectrum).
Results/Discussion
In this study iron oxide nanoparticles synthesized at BAM and pre-characterized by DLS, SEM (including the transmission mode STEM-in-SEM) are presented. The particles are spherical and highly monodisperse with sizes slightly larger than 10 nm.
T2 - Nanosafe 2020
CY - Online meeting
DA - 16.11.2020
KW - Reference nanomaterials
KW - Imaging techniques
KW - Size and size distribution
KW - Reliable characterization
KW - Iron oxide nanoparticles
PY - 2020
AN - OPUS4-51767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Hennecke, M.
ED - Skrotzki, Birgit
T1 - Hütte Band 3: Elektro- und informationstechnische Grundlagen für Ingenieure
N2 - Die HÜTTE ist ein Kompendium und Nachschlagewerk für unterschiedliche Aufgabenstellungen. Durch Kombination der Einzeldisziplinen dieses Wissenskreises kann das multidisziplinäre Grundwissen für die verschiedenen Technikbereiche und Ingenieuraufgaben zusammengestellt werden.
Die HÜTTE enthält in drei Bänden - orientiert am Stand von Wissenschaft und Technik und den Lehrplänen der Technischen Universitäten und Hochschulen - die Grundlagen des Ingenieurwissens.
Band 3 enthält die Elektro- und informationstechnische Grundlagen.
KW - Elektrotechnische Grundlagen
KW - Informationstechnische Grundlagen
PY - 2023
SN - 978-3-662-64374-7
DO - https://doi.org/10.1007/978-3-662-64375-4
SN - 2522-8188
SP - 1
EP - 923
PB - Springer Vieweg
CY - Berlin
ET - 35
AN - OPUS4-57137
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schusterbauer, Robert
T1 - Correlative chemical imaging to reveal the nature of different commercial graphene materials
N2 - Since the original report in 2004 by Novoselov and Geim, Graphene gained incredible attention due to its fascinating properties. In the past 20 years, the synthesis and functionalization of graphene has evolved significantly[3]. Different synthesis techniques were developed which led to other graphenerelated materials such as graphene oxide (GO) or elemental-doped graphene. Further chemical functionalization can enhance but also alter or reduce specific properties of the graphene. To reveal the nature of these materials a proper physico‑chemical characterization with different analytical techniques is crucial.
Single-layer GO flakes kindly provided by Graphenea (Spain) were prepared for systematic image analysis. These flakes were disposed on an alignment-marked SiO2 substrate and correlatively imaged by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Raman spectroscopy. The high lateral resolution and/ or extreme surface sensitivity of the mentioned
techniques is necessary to explore monolayers. The ToF-SIMS images match well with the SEM and AFM images and provide information about the chemistry. With 2D Raman spectroscopy it is possible to differentiate between the number of stacked single-layer flakes. This is visualized in a 3D image (Figure b). Well-defined GO flakes could be used as a reference material for imaging of graphene-like structures but also of other types of 2D materials.
In addition to these monolayer GO flakes, commercial graphene-containing inks (Haydale) with a more complex morphology were also correlatively imaged. ToF-SIMS and SEM images were merged to identify the origin of different chemical fragments. The findings correlate closely with the expectation that the specific functionalizations (with fluorine and nitrogen as marker elements) are present only on the graphene flakes as presumed from the SEM images. Energy-dispersive X-ray spectroscopy (EDX) supports these results, yet with a much lower sensitivity compared to ToF-SIMS.
T2 - MaterialsWeek 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Graphene oxide flakes
KW - ToF-SIMS
KW - SEM
KW - Raman
KW - Correlative imaging
PY - 2024
AN - OPUS4-60681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chahal, Shweta
A1 - Xiao, Boyu
A1 - Grant, Jessica
A1 - Furniss, David
A1 - Farries, Mark
A1 - Phang, Sendy
A1 - Neate, Nigel
A1 - Robertson, Lorelei
A1 - Roe, Martin
A1 - Barney, Emma
A1 - Seddon, Angela B.
T1 - Ce3+-doped chalcogenide glass fibre for laser beyond 4 microns wavelength: Glass material-integrity
N2 - The 4-μm wavelength barrier encountered for mid-infrared fibre lasing based on heavy metal fluoride glasses has been overcome. We reported, in 2021, the first continuous wave, mid-infrared fibre laser operating beyond 4 μm at room temperature in a fibre with a Ce3+-doped selenide-chalcogenide core. Defects, such as crystallites in the core glass, could cause unwanted light-scattering, diminishing fibre laser efficiency. It is important to identify such optical loss mechanisms and eradicate them. Here, we report on investigating the material nano-structure of a chalcogenide-glass lasing fibre which exhibits 7 mW laser power output; the fibre has a Ce3+-doped core (8.5 μm diameter), concentrically surrounded by an inner- and outer-cladding, where both cladding-glasses are nominally the same composition. High resolution transmission electron microscopy and electron diffraction show that the core, inner-cladding and outer-cladding of the lasing fibre are internally nano-crystallite-free and amorphous. However, the external outer surface of the last 10 m of fibre drawn, of the total 100 m, contains monoclinic GeSe2 crystallites adjacent to discrete, small (<0.5 mm) wrinkled defects. The final length of fibre is drawn from the final part of the glass fibreoptic preform. The glass preform has as its outermost component an extruded chalcogenide glass tube. It is the last part of the tube which spends the longest time at high temperature inside the extruder during tube manufacture, encouraging heterogeneous nucleation at the tube outer-surface in contact with the extruder. These heterogeneous nuclei subsequently nucleate crystal growth during fibre-drawing in the outermost fibre surface.
KW - Optical glass
KW - Photonics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653371
DO - https://doi.org/10.1016/j.optmat.2025.117219
SN - 0925-3467
VL - 166
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65337
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaunich, Matthias
T1 - Investigations of Aged Metal Seals for Interim Storage
N2 - The storage of spent fuel and high level radioactive waste in Germany is performed in interim storage containers with double lid systems. The lids are bolted and equipped with metal seals (e.g. Helicoflex®) to ensure the safe enclosure of the inventory. The used metal seals have a layered structure consisting of three components as can be seen schematically in the cross-sectional view in Fig. 1.
In the center a helical spring is positioned that is surrounded by two C-shaped jackets and is mainly responsible for generation of the required restoring force. The inner jacket is made of stainless steel and homogenizes the restoring force of the helical spring. The outer jacket is made of silver or aluminium which both are soft metals in comparison to the contact partners (lid and container body). During bolting of the lid to the container body the seal is compressed. The generated restoring force of the helical spring causes a plastic deformation of the outer jacket and adapts to the surfaces of the lid and the container body. Hence, leakage paths are closed and the sealing function is generated.
Typical durations for existing interim storage licenses in Germany are 40 years, but it can be expected that they have to be extended to longer periods as a final repository will not be available before the end of the running licence periods. This extension of license periods requires a solid understanding of the long-term behaviour of the seals under storage conditions. To meet this challenge long-term investigations have been started at Bundesanstalt für Materialforschung und –prüfung (BAM) in 2009. These tests focus on seals assembled in test flanges which are stored at temperatures ranging from room temperature to 150 °C for accelerated ageing. The aged seals are tested repeatedly after certain ageing steps and the leakage rate as indicator for sealing performance, the remaining seal force, and the useable resilience upon decompression are determined.
In the poster an update on the performed investigations in respect to earlier publications (Grelle et al. 2019, Goral et al. 2023) will be given and the implications of the results for resilient long term safety will be presented. Additionally, a focus will be laid on the currently planned further investigations and the question “What is additionally needed for evaluation of an interim storage period extension in regard to the used metal seals?” will be addressed.
T2 - safeND2023: Forschungssymposium des BASE
CY - Berlin, Germany
DA - 13.09.2023
KW - Metal seal
KW - Interim storage
KW - Ageing
PY - 2023
AN - OPUS4-58568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaunich, Matthias
T1 - Elastomerdichtungen für Wasserstoffanwendungen - Vergleich des Alterungsverhaltens in Luft und Wasserstoff
N2 - In diesem Beitrag soll ein Fokus auf das Alterungsverhalten von Elastomerdichtungen unter Wasserstoff gelegt werden. Hierfür wurden Untersuchungen bei einem mittleren Wasserstoffdruck über Alterungszeiten von bis zu 100 Tagen durchgeführt. Das Alterungsverhalten wird im Vergleich der Alterungseffekte unter thermooxidativen Bedingungen betrachtet und bewertet.
Die Annahme, dass der Alterungseffekt unter Wasserstoff stets weniger ausgeprägt ist als an Luft bestätigt sich nicht durch die Ergebnisse.
T2 - 4. O-Ring-Forum der Firma ISGATEC
CY - Bad Schönborn, Germany
DA - 15.05.2025
KW - Wasserstoff
KW - Dichtung
KW - Thermische Alterung
KW - Elastomer
PY - 2025
AN - OPUS4-63135
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hodoroaba, Vasile-Dan
ED - Hodoroaba, Vasile-Dan
T1 - Liaison Report from ISO/TC 202 'Microbeam Analysis' to ISO/TC 229 'Nanotechnologies'
N2 - Liaison activities within ISO/TC 202 'Microbeam Analysis' which are relevant to ISO/TC 229 'Nanotechnologies' are reported acoording to the structure defined by ISO/TC229 Nanotechnologies Liaisons Coordination Group (NLCG): new standards/documents, coordination issues, and further detailed specific information, e.g. publications, events, comments.
KW - ISO/TC 229 Nanotechnologies
KW - ISO/TC 202 Microbeam Analysis
KW - Standardisation
PY - 2023
SP - 1
EP - 3
CY - ISO, Geneva, CH
AN - OPUS4-58986
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dumit, Verónica I.
A1 - Furxhi, Irini
A1 - Nymark, Penny
A1 - Afantitis, Antreas
A1 - Ammar, Ammar
A1 - Amorim, Monica J. B.
A1 - Antunes, Dalila
A1 - Avramova, Svetlana
A1 - Battistelli, Chiara L.
A1 - Basei, Gianpietro
A1 - Bossa, Cecilia
A1 - Cimpan, Emil
A1 - Cimpan, Mihaela Roxana
A1 - Ciornii, Dmitri
A1 - Costa, Anna
A1 - Delpivo, Camilla
A1 - Dusinska, Maria
A1 - Fonseca, Ana Sofia
A1 - Friedrichs, Steffi
A1 - Hodoroaba, Vasile-Dan
A1 - Hristozov, Danail
A1 - Isigonis, Panagiotis
A1 - Jeliazkova, Nina
A1 - Kochev, Nikolay
A1 - Kranjc, Eva
A1 - Maier, Dieter
A1 - Melagraki, Georgia
A1 - Papadiamantis, Anastasios G.
A1 - Puzyn, Tomasz
A1 - Rauscher, Hubert
A1 - Reilly, Katie
A1 - Jiménez, Araceli Sánchez
A1 - Scott‐Fordsmand, Janeck J.
A1 - Shandilya, Neeraj
A1 - Shin, Hyun Kil
A1 - Tancheva, Gergana
A1 - van Rijn, Jeaphianne P. M.
A1 - Willighagen, Egon L.
A1 - Wyrzykowska, Ewelina
A1 - Bakker, Martine I.
A1 - Drobne, Damjana
A1 - Exner, Thomas E.
A1 - Himly, Martin
A1 - Lynch, Iseult
T1 - Challenges and Future Directions in Assessing the Quality and Completeness of Advanced Materials Safety Data for Re‐Usability: A Position Paper From the Nanosafety Community
N2 - Ensuring data quality, completeness, and interoperability is crucial for progressing safety research, Safe‐and‐Sustainable‐by‐Design approaches, and regulatory approval of nanoscale and advanced materials. While the FAIR (Findable, Accessible, Interoperable, and Re‐usable) principles aim to promote data re‐use, they do not address data quality, essential for data re‐use for advancing sustainable and safe innovation. Effective quality assurance procedures require (meta)data to conform to community‐agreed standards. Nanosafety data offer a key reference point for developing best practices in data management for advanced materials, as their large‐scale generation coincided with the emergence of dedicated data quality criteria and concepts such as FAIR data. This work highlights frameworks, methodologies, and tools that address the challenges associated with the multidisciplinary nature of nanomaterial safety data. Existing approaches to evaluating the reliability, relevance, and completeness of data are considered in light of their potential for integration into harmonized standards and adaptation to advance material requirements. The goal here is to emphasize the importance of automated tools to reduce manual labor in making (meta)data FAIR, enabling trusted data re‐use and fostering safer, more sustainable innovation of advanced materials. Awareness and prioritization of these challenges are critical for building robust data infrastructures.
KW - Advanced materials
KW - Safety data
KW - Re-usability
KW - Nanosafety
KW - SSbD
KW - FAIR
KW - Standardisation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652918
DO - https://doi.org/10.1002/adsu.202500567
SN - 2366-7486
SP - 1
EP - 18
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Kai
T1 - ToF-SIMS as a new tool for nano-scale investigation of ps-laser generated surface structures on Titanium substrates
N2 - The fabrication of laser-generated surface structures on titanium and titanium alloys has recently gained remarkable interests, being technologically relevant for applications in optics, medicine, fluid transport, tribology, and wetting of surfaces. The morphology of these structures, and so their chemistry, is influenced by the different laser processing parameters such as the laser fluence, wavelength, pulse repetition rate, the effective number of laser pulses per beam spot area, etc. A simple way to characterize laser-generated surface structures is by means of optical microscopy (OM) or white light interference microscopy (WLIM). The latter can address the surface topography, while having a lateral resolution limit of ~(lambda)/2 (lambda = illumination wavelength). To resolve morphologies with spatial periods significantly smaller than (lambda)/2, scanning electron microscopy (SEM) is often used, taking benefit of the reduced de Broglie wavelength associated to the electrons of several keV energy. However, all the above-mentioned techniques lack the necessary depth-resolution to reveal and quantify sub-surface material modifications of these laser-generated structures. Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) represents a promising surface analytical technique for studying laser-induced chemical surface alterations since the method combines a high surface sensitivity with the capability to perform a depth-profiling of the laser-affected surface zone. In this study we combine WLIM and high-resolution SEM with ToF-SIMS to fully characterize the evolution of various types of laser-generated micro- and nanostructures formed on Ti-6Al-4V alloys upon irradiation by near infrared ultrashort laser pulses (1030 nm, 925 fs) at different laser fluence levels, effective number of pulses, and at different pulse repetition rates (1 – 400 kHz). We show how this combined surface analytical approach allows to evaluate alterations in the surface chemistry and topography of the laser-generated surface structures depending on the laser processing parameters
T2 - ECASIA 2022
CY - Limerick, Ireland
DA - 29.05.2022
KW - Laser-induced periodic surface structures
KW - Time of Flight - Secondary ion mass spectrometry
KW - White light interferometric microscopy
KW - Titanium alloy
PY - 2022
AN - OPUS4-54992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Graphene Week - Training Session: Standardisation and Validation
N2 - In this training session the standardisation landscape will be presented. Another focus is how science can put into standards. In the second part the validation of protocols will be validated. Reference materials and interlaboratory comparisons as validation tools will be discussed.
T2 - Graphene Week 2024
CY - Prague, Czech Republic
DA - 14.10.2024
KW - Precision
KW - Trueness
KW - Accuracy
KW - Interlaboratory comparison
KW - Certified reference materials
PY - 2024
AN - OPUS4-61469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fernandez-Poulussen, D.
A1 - Hodoroaba, Vasile-Dan
T1 - Holistic, reliable and practical Characterization Framework for Graphene Family Materials, a correlated approach including Imaging based techniques
N2 - ACCORDs is an Horizon Europe project working in the development of an imaging-based characterization framework (ACCORDs framework) for the holistic correlative assessment of Graphene Family Materials (GFMs) as a representative of 2D nanomaterials (NMs) to assess and predict 2D NMs health and environmental risks. The ACCORDs framework will operationalise safe and sustainable by design (SSbD) strategies proposed in past or ongoing H2020 projects or within OECD by correlating low-, medium-, and high-resolution physico-chemical-biological imaging-based methods with non-imaging methods in a tiered approach. ACCORDs will deliver the ACCORDs framework and user guidance, new imaging-based characterisation methods, reference in vitro tests, new reference 2D NMs for different matrices, a new minimum information reporting guideline for FAIR data sharing and reuse of images as well as an atlas with reference images for diagnostics of compromised safety of GFMs/GFM products. The new guidelines and standard proposals will be submitted to standardisation bodies to allow creation of regulatory ready products. The novelty of ACCORDs is in translating the principles of medical imaging-based diagnostics to 2D material hazard diagnostics. ACCORDs will accelerate industrial sectors in the area of aviation, marine construction, drone production, flexible electronics, photovoltaics, photocatalytics and print inks-based sensors. The value ACCORDs proposes to the graphene industry are practical, easy, imaging-based tools for GFM quality monitoring next to the production line with a possibility to be correlated with advanced highresolution imaging characterization methods in case hazard i.e. deviation from controls (benchmark values) are diagnosed. The ACCORDs framework and tools will contribute to the European Green Deal by addressing the topic: “Graphene: Europe in the lead” and to a new European strategy on standardization, released on 2nd February, 2022.
T2 - MaterialsWeek 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Graphene
KW - Graphene-related 2D materials
KW - SSbD
KW - Imaging
KW - ACCORDs
PY - 2024
AN - OPUS4-60573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Towards Standardised Procedures for Morphology Measurement of 2D-Materials by Imaging
N2 - The industry uptake of graphene-related 2D materials (GR2M) material increases, and international standardization is critical to enable commercialization. Reliable, accurate, and reproducible measurements are important due to the multiple production routes and producers of the material to maintain quality in manufacture.
Several standards are under development within ISO/TC 229 ‘Nanotechnologies’, i.e. ISO/AWI TS 23879 “Structural characterization of graphene oxide flakes: thickness and lateral size measurement using AFM and SEM” or ISO DTS 23359 “Chemical characterization of graphene in powders and suspensions”, which focus on determining the dimensional and chemical properties of GR2M. Interlaboratory comparisons are required to develop best practice and understand the associated measurement uncertainties.
In this contribution challenges and solutions for the accurate measurement of the lateral size of GR2M will be discussed based on the results of a recently completed interlaboratory comparison organized under the pre-standardisation platform of VAMAS (www.vamas.org/twa41/documents/2023_vamas_twa41_project13_GO_SEM.pdf). Aspects related to sample preparation, measurement conditions, and image analysis with different approaches to extract the corresponding size and shape descriptors will be presented. A discussion on the measurement uncertainty budget associated to the final result will be also included.
T2 - Graphene Week 2025
CY - Vicenza, Italy
DA - 22.09.2025
KW - Graphene-related 2D materials (GR2M)
KW - Interlaboratory comparison
KW - VAMAS
KW - Lateral size
KW - ISO/TC 229 Nanotechnologies
PY - 2025
AN - OPUS4-64250
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knigge, Xenia
A1 - Guo, Z.
A1 - Valsami-Jones, E.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Influence of Sterilization on the Surface of Nanoparticles Studied with XPS / HAXPES in Comparison to SEM / EDS
N2 - Nanosafety is becoming increasingly important as nanomaterials are widely used in industrial processes and consumer products. For nanotoxicity measurements prior sterilization of the samples is necessary, but as structure activity relationships are made with properties of pristine particles, the question arises, if the sterilization process has an impact on the physico-chemical properties of nanoparticles and thus on the biological behavior.
This question will be addressed in this talk. For this purpose, results from SEM and EDS measurements are combined with those of a novel lab-based HAXPES spectrometer in order to obtain a more complete picture. At the end, an influence of sterilization will be evident, which indicates a restructuring of the nanoparticles owing to sterilization.
T2 - Microscopy & Microanalysis 2022
CY - Portland, USA
DA - 31.07.2022
KW - XPS
KW - HAXPES
KW - SEM
KW - EDS
KW - Nanoparticles
PY - 2022
DO - https://doi.org/10.1017/S1431927622004287
VL - 28
SP - 986
EP - 988
PB - Cambridge University Press
AN - OPUS4-55352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eggert, Claudia
A1 - Hodoroaba, Vasile-Dan
T1 - Welcome and Introduction
N2 - Nanotechnology has emerged over the past decade as a key field involving the design, characterization, production, and application of materials, structures, devices, and systems at the nanometer scale. Due to their large specific surface area and significant surface chemistry, nanomaterials offer enhanced material properties and product functionalities.
However, alongside these advancements comes the potential risk to humans and the environment. The development of nanomaterials has provided new opportunities to understand matter at the nanoscale, accelerating the creation of innovative advanced materials and devices. The expertise gained in the standardization and regulation of nanomaterials, particularly in characterizing nanoparticulate matter, should be applied to other innovative advanced materials, such as (nano)composites, 2D structures, additive manufactured materials, gels, and foams. Initial guidance for the safe-and-sustainable-by-design (SSbD) development of advanced materials during the early innovation phase has been introduced by various groups and projects. Additionally, digital material passports (DMP) and digital product passports (DPP) need to be defined and implemented uniformly across Europe.
In 2024, the Innovative Advanced Materials Initiative (IAM-I) was launched by European stakeholders to contribute to a "Research and Innovation ecosystem that will significantly accelerate the time-to-market of sustainable innovative advanced materials (IAMs) and associated technologies designed for a digital circular economy." Knowledge transfer is a crucial pillar of this ecosystem, and a future IAM-I Academy could be a valuable tool. Initially, it is essential to define "education & training needs to boost Europe’s competitiveness and sovereignty within the area of IAM."
T2 - Nano and Beyond - What can we learn from Nano for other Innovative Advanced Materials?
CY - Online meeting
DA - 04.07.2025
KW - Advance Materials
KW - Nanomaterials
KW - IAM-I
KW - SSbD
KW - DMP
KW - DPP
PY - 2025
UR - https://www.bam-akademie.de/kursangebot/kurs/webinar-nano-and-beyond-55.html?lang=en
AN - OPUS4-63690
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Advanced physico-chemical Characterisation & Correlation of Results with different Methods for GFMs
N2 - An accurate characterisation of the morphological, structural, and chemical properties of nano and advanced materials is key for the understanding of the material functionality and constitutes the basis for future optimisation or even prediction of the product performance. Further, the correlation of the physical-chemical properties with results from biological testing leads to an understanding of the potential toxicological effects so that a minimisation of the materials risks becomes possible.
The presentation will highlight with examples the importance of the selection of the relevant parameters/descriptors and particularly their measurement for the reliable characterisation of the morphology, structure, and chemistry of graphene-related 2D-materials (GR2M’s) [1-3]. One crucial aspect is also one of most challenging ones in the characterisation chain: the proper sample preparation, which shall be tailored to the accurate measurement of the defined analytical parameter. Practical examples of measurement of morphological descriptors of GR2M’s, such as equivalent circular diameter (ECD), minimum and maximum Feret, and aspect ratio with electron microscopy, or of the thickness with atomic force microscopy (AFM) will be showed, together with quantitative chemical characterisation with X-ray photoelectron spectroscopy (XPS) and, newly, with energy-dispersive X-ray spectroscopy with a scanning electron microscope (SEM/EDX) [4] by evaluating accurately the elemental content as the ratio of O/C and the composition of impurities.
Another relevant, but challenging part of the characterisation of GR2M’s, particularly as the final products containing mostly low amounts of GR2M’s, is the analysis of homogeneity of the chemical composition by sensitive imaging methods. Examples of successful analysis with secondary ion mass spectrometry (SIMS), even if not quantitative, will be presented.
T2 - Joint online Workshop: Harmonisation & Standardisation of Test Methods for Nano- and Advanced Materials
CY - Paris, France
DA - 19.06.2025
KW - Physico-chemical characterisation
KW - Graphene-related 2D materials
KW - OECD
KW - Standardisation
KW - GO flakes
PY - 2025
UR - https://macrame-project.eu/macrame-meetings-workshops/ws_hamonisation_standardisation_2023/
AN - OPUS4-63557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - (Pre)Standardisation and Metrology in Microbeam Analysis – Ongoing Activities and Opportunities
N2 - The presentation addresses the current ongoing projects as well as the gaps and opportunities in microbeam analysis within ISO/TC 202 Microbeam Analysis standardisation body and in-liaison Technical Working Areas (TWAs) at the pre-standardization platform of VAMAS (Versailles Project on Advanced Materials and Standards).
T2 - EMAS 2023 - 17th European Workshop on Modern Developmennts and Applications in Microbeam Analysis - General Assembly
CY - Krakow, Poland
DA - 07.05.2023
KW - Microbeam analysis
KW - EDS
KW - Electron microscopy
KW - Inter-laboratory comparison
KW - EBSD
KW - Standardisation
PY - 2023
AN - OPUS4-57483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Measurement of the Lateral Size of Graphene Oxide Flakes by SEM
N2 - The progress of the VAMAS interlaboratory comparison Project P13 "Lateral size of graphene oxide flakes by SEM" within the Technical Working Area 41 "Graphene and Related 2D Materials" is presented. The challenges at sample preparation on substrates for accurate measurement and image analysis as well as two different analysis approaches, containing exact guidance how to measure the main descriptors for the lateral size measurement of the imaged graphene oxide flakes with Scanning Electron Microscopy are highlighted. The size and shape distributions as measured by 17 laboratories are showed expressed in size and shape descriptors extracted from SEM images by using two proposed measurement approaches.
The implementation of the results into the corresponding ISO technical specification AWI/TS 23879 is discussed and planned, in relation with the AFM part.
T2 - ISO/TC 229 Nanotechnologies Meeting Week
CY - Stockholm, Sweden
DA - 19.05.2025
KW - Graphene oxide
KW - Interlaboratory comparison
KW - SEM
KW - Lateral size
KW - VAMAS
KW - ISO/TC 229 Nanotechnologies
PY - 2025
AN - OPUS4-63189
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Moor, Maëlle
A1 - Kraehnert, Ralph
A1 - Hodoroaba, Vasile-Dan
A1 - Hertwig, Andreas
T1 - Ellipsometry-based approach for the characterization of mesoporous thin films for H2 technologies
N2 - Porous thin layer materials are gaining importance in different fields of technology and pose a challenge to the accurate determination of materials properties important for their function. In this work, we demonstrate a hybrid measurement technique using ellipsometry together with other independent methods for validation. Ellipsometry provides information about the porosity of different mesoporous films (PtRuNP/OMC = 45%; IrOx = 46%) as well as about the pore size (pore radius of ca. 5 nm for PtRuNP/OMC). In addition, the electronic structure of a material, such as intraband transitions of a mesoporous IrOx film, can be identified, which can be used to better understand the mechanisms of chemical processes. In addition, we show that ellipsometry can be used as a scalable imaging and visualization method for quality assurance in production. These require accurate and traceable measurements, with reference materials playing an important role that include porosity and other related properties. We show that our novel analytical methods are useful for improving analytical work in this entire field.
KW - Porous materials
KW - Electrolysis
KW - Spectroscopic ellipsometry
KW - Hybrid metrology measurement
KW - Electron microscopy
PY - 2021
DO - https://doi.org/10.1002/adem.202101320
SP - 1
EP - 17
PB - Wiley-VCH
AN - OPUS4-53960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - VAMAS interlaboratory comparisons on nanoparticles associated with the outcomes of the EMPIR project nPSize
N2 - Following points are presented and discussed: i) nPSize as an EMPIR project on the nanoparticle size and shape distribution of (more) complex particles including sample preparation and machine learning approaches; ii) parallel development of ISO 21363 (PSSD by TEM), ISO 19749 (PSSD by SEM), ISO 22292 (3D TEM), ISO 52408 (NP Prep for AFM and EM), iii) VAMAS and pre-standardisation, TWA 34 „Nanoparticle Populations“ with two nPSize ILC projects P15 & P16 – results to be published and integrated in ISO 21363 (PSSD by TEM); iv) Remaining challenges: platelets, 2D materials (TiO2 and GR2M); v) Reference data sets as part of a complete Characterisation Workflow.
T2 - How to identify Nanomaterials more effectively? Good Practices and Ways to Progress
CY - Paris, France
DA - 11.05.2023
KW - Nanoparticles
KW - VAMAS
KW - nPSize
KW - Particle size distribution
KW - Nanoparticle concentration
KW - Interlaboratory comparison
PY - 2023
UR - https://www.lne.fr/fr/service/formation/journee-technique-nanomateriaux-comment-identifier-efficacement-nanomateriaux?utm_source=Twitter&utm_medium=Tweet&utm_campaign=JT2301
AN - OPUS4-57485
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Ongoing VAMAS ILC s on Nanoparticles and Graphene Oxide
N2 - This contributions shows the first results of the ongoing interlaboratory comparisons under VAMAS/TWA 34 Nanoparticle populations related on the determination of pasrticle size distribution and relative concentration of nanoparticles and an example of an ILC running under VAMAS/TWA 41 Graphene and Related 2D Materials on the determination of the lateral diemsnions of graphene oxide flakes by Scanning Electron Microscopy. The link to related standardisation projects at ISO/TC Nanotechnologies are explained.
T2 - Webinar Building the Foundation: Interlaboratory Comparisons and Reference Products for Advanced Materials
CY - Berlin, Germany
DA - 16.05.2024
KW - Nanoparticles
KW - VAMAS
KW - Interlaboratory comparison
KW - Standardisation
KW - Electron microscopy
KW - AFM
KW - SAXS
PY - 2024
AN - OPUS4-60097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
T1 - High cycle fatigue behavior of alloy EN AW-2618A
N2 - The presentation shows the results of high cycle fatigue (HCF) tests from the aluminium alloy EN AW-2618A. This study investigates the mean stress influence in the T61 condition and the effect of overaging. For this purpose, axial HCF tests were carried out at room temperature and different stress ratios (R=-1, R=0.1) as well as with overaged conditions (T61+10h@230°C, T61+1000h@230°C). After completion of the tests, the fracture surfaces were examined to study crack initiation.
T2 - The 18th International Conference on Aluminium Alloys
CY - Toyama, Japan
DA - 04.09.2022
KW - High Cycle Fatigue
KW - Aluminium Alloy
KW - EN AW-2618A
PY - 2022
AN - OPUS4-55865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Habibimarkani, Heydar
T1 - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) for in situ investigation on FeNi nanoparticles
N2 - The modern economy is dependent on catalysis, which is main efforts to create environmentally and energy-friendly technologies. The storage of excess electrical energy into chemical energy by splitting water into hydrogen and oxygen is a feasible solution to this energy demand. Due to their abundance on Earth and inherent stability in alkaline solution, transition-metal oxides have become one of several viable alternatives to noble-metal catalysts. Since NiFe oxide is one of the most active oxygen evolution reaction (OER) electrocatalysts for alkaline water electrolysis, it has been the subject of extensive research.
In this work, NiFe2O4 nanoparticles (NPs) of various sizes, specific stoichiometric and non-stoichiometric Fe:Ni surface ratios are synthesized. we will use a combination of ultra-high vacuum surface analysis techniques, such as time-of-flight secondary ion mass spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS), to obtain the detailed characterization of the OER electrocatalysts top-surface layer, which is required to identify the rate-limiting step intermediates, and surface morphological changes at the electrolyte/catalyst.
T2 - SALSA Make&Measure 2022
CY - Berlin, Germany
DA - 15.09.2022
KW - ToF-SIMS
KW - FeNi nanoparticles
PY - 2022
AN - OPUS4-56157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - The next steps in the standardisation of graphene-related and other 2D materials (GR2M)
N2 - The first products with graphene-related 2D material (GR2M) are on the market. In this phase trust is essential for the commercial success of these products, between the individual partners of the product value chain, and between the manufacturer and the consumer. Standards are an important tool for building this trust. The first steps have been taken in standardisation, e.g. in terminology and the characterization of raw materials. But there are still some challenges to overcome such as bringing the standards to the factory floor and real-world products. For the validation of new protocols and methods there is a need of reference data and materials. But not only the measurement should be reproducible, the whole analytical workflow from sample storage and preparation to data analysis should be reproducible. Another important issue is the establishment of credible structure-activity relationships which allows the prediction of the properties of the GR2M, but also of the biological activity including the safety for the human health and the environment. Such relationships can be used for read-across and grouping and can facilitate the regulation of the advanced materials.
In addition, 2D materials beyond graphene should also be considered and can benefit from the experience from the standardisation of graphene and graphene oxide.
T2 - Nanomaterials Standardization Strategy Forum - Europe - Republic of Korea
CY - Online meeting
DA - 08.07.2025
KW - Commercialisation
KW - Product-value chain
KW - Confidence building
PY - 2025
AN - OPUS4-63731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mrkwitschka, Paul
T1 - Standardized Chemical Composition Analysis of Graphene Oxide Flakes with SEM/EDS and XPS Works Reliably
N2 - Reliable quantification of the chemical composition of graphene-related 2D materials as powders and liquid suspensions is a challenging task. Analytical methods such as XPS, ICP-MS, TGA and FTIR are recommended to be used in ongoing projects at standardization bodies. The specific parameters to be measured are also defined, e.g. the oxygen-to-carbon (O/C) concentration ratio, the trace metal impurities, or the functional groups present [1]. In this contribution, for the first time, the results of a systematic study on the capability of SEM/EDS to reliably quantify the O/C ratio in a well-defined and well-characterized graphene oxide material [2] are presented. It is expected that the quantitative EDS analysis of light elements emitting characteristic X-ray lines below 1 keV to be provided with significantly larger measurement uncertainties than the analysis of elements with an atomic number of 11 (Na) or above [3]. The robustness of the SEM/EDS results obtained at various measurement conditions (various excitation energies) is tested by comparing the results to the established XPS analysis [4], which has been carried out on the same samples.
A crucial step in sample preparation from liquid suspension with graphene oxides flakes onto a substrate for analysis with both XPS and EDS. It is demonstrated that if a closed and enough thick drop-cast deposited spot is succeeded to be deposited on a substrate, both surface-sensitive XPS analysis and bulk-characterizing EDS result in very similar elemental composition of oxygen and carbon. Hence, theoretical, expected O/C atomic ratio values for pure graphene oxide of ~0.5 [1] are achieved (with both methods), see Figure 1. Further, the effect of untight deposited material enabling co-analysis of the (silicon) substrate, is evaluated for both methods, XPS and EDS. To note that all the EDS results in this study have been quantified standardless.
The effect of the variation of beam voltage on the result of the quantification of the O/C ratio is shown in Figure 2. No clear tendency is visible by varying the kV, which is a confirmation of the quality of the standardless analysis at the used EDS spectrometer.
The results of this study demonstrate the reliability of the reference measurement protocol for SEM/EDS to be introduced into ISO/DTS 23359, including the dedicated sample preparation, particularly for the cases when the concentration of the GO flakes in stock liquid suspension is low. Further, also the consideration of this GO material as one of the very few available as a commercial material on the market as the very first GO reference material with regard to its morphology as well as chemical composition. Both the standard measurement procedure and the candidate reference material will immensely contribute to characterise reliably the chemical composition of graphene-related 2D materials with SEM/EDS as one of the most widely used methods in analytical laboratories.
T2 - Microscopy and Microanalysis 2025
CY - Salt Lake City, UTAH, USA
DA - 27.07.2025
KW - Graphene oxide flakes
KW - SEM/EDS
KW - XPS
KW - O/C ratio
KW - Impurities
PY - 2025
AN - OPUS4-64085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Liaison report from VAMAS with ISO/TC 202 Microbeam Analysis
N2 - The progress in the activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects/inter-laboratory comparisons. The recently started project FIB sample processing for TEM is presented. Next projects in the pipeline involving EBSD and TKD are shortly announced. The need of more promotion for the engagement of more experts from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed.
T2 - 29th Annual Meeting of ISO/TC 202 Microbeam Analysis
CY - Online meeting
DA - 28.11.2022
KW - VAMAS
KW - ISO/TC 202
KW - Microbeam Analysis
KW - EBSD
KW - Electron microscopy
KW - Thin films
PY - 2022
AN - OPUS4-56424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chemello, Giovanni
T1 - Towards Reproducible Analysis Workflows for Reliable Structural and Chemical Composition of Industrial Graphene
N2 - The scientific and technological interest in graphene has been growing more and more in the late years due to its outstanding properties and diverse promising applications. However, graphene implementation into the industrial market is still limited and many challenges are yet to be addressed before this material can become suitable for the large-scale production. One of the most crucial challenge to overcome is to develop reliable and reproducible ways to characterize the material properties which can heavily affect the product performance. In our study the chemical composition of nine different samples of industrial graphene, graphene oxide and functionalized graphene were investigated. The samples were analysed both in form of powder and pellets. A comparative characterisation of the chemical composition was performed through X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDX). XPS depth resolution is in the order of 10 nm, while for EDX the analysis was performed at two different energy levels, i.e. 5 keV and 15 keV, and thus varying the analysis depth from 200 nm to 2000 nm. The XPS measurement area is 300x700 µm² while the EDX measurement was performed by analysing a grid of 25 locations (5x5) of 150 x 150 ?m2 area, covering the whole pellet surface of 5 mm diameter and then calculating the mean of the elemental concentration. The results of the elemental concentration values from XPS and EDX analyses show a good agreement for all the elements presents in the samples, despite the different spatial resolutions of the two techniques. Therefore, the samples appear homogeneous both in the lateral and vertical directions. The results relative to powder and pellets samples do not differ in a significant way except for a slight increase in the carbon content regarding the pellet samples, probably due to a minor contamination effect introduced through pressing. Nevertheless, pellets samples appear to be quite representative for the material while being much more convenient in terms of handling and safety compared to nano-powders and providing a regular flat surface for EDX analysis. Finally, this approach correlating XPS and EDS represents a simple, fast and reliable way for characterizing the chemical composition and the homogeneity of industrial graphene. This study is part of the project Standardisation of structural and chemical properties of graphene (ISO-G-SCoPe) which has received funding from the EMPIR programme co-financed by the Participating States and from the European Union?s Horizon 2020 research and innovation programme under Grant agreement No. 19NRM04.
T2 - SALSA Make and Measure... and Machines
CY - Online meeting
DA - 16.09.2021
KW - Graphene
KW - XPS
KW - EDX
KW - Graphene functionalisation
PY - 2021
UR - https://fakultaeten.hu-berlin.de/en/mnf/forschung_internationales/grs/salsa/SALSA_MM
AN - OPUS4-53463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - About Interlaboratory Comparisons (ILCs) and VAMAS
N2 - Advanced materials, such as nanomaterials, 2D materials, or thin films, play a crucial role in driving economic development and addressing major challenges in the coming years. These challenges include mitigating the impact of climate change, advancing lightweight engineering, enhancing catalysis, and improving medical applications.
To comprehend the performance of these materials and ensure their acceptance across various sectors as safe and sustainable for both humans and the environment, the availability of reference procedures, materials, and data is essential. One versatile tool for establishing such references and evaluating the proficiency of individual laboratories and their competencies is through (international) interlaboratory comparisons (ILC). Notably, initiatives like the Versailles Project on Advanced Materials and Standards (VAMAS) provide a platform for conducting ILCs.
This webinar will showcase various examples of interlaboratory comparisons, illustrating their impact on the development of reference products.
T2 - Webinar Building the Foundation: Interlaboratory Comparisons and Reference Products for Advanced Materials
CY - Berlin, Germany
DA - 16.05.2024
KW - Interlaboratory comparison
KW - Reference products
KW - VAMAS
KW - Standardisation
PY - 2024
AN - OPUS4-60096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Morphology Analysis of Graphene Oxide Flakes with SEM - Preparation of an Inter-Laboratory Comparison @VAMAS
N2 - Experience gained at BAM within the European project ISGScope on the accurate measureemnt of graphene oxide flakes by electron microscopy is presented. Particularly, factors such as the type of solvent, substrate temperature, but also proper, gentle measurement parameters and image analysis conditions towards automation are highlighted. The measurement procedures in develeopment are being prepared to launch an inter-laboratory comparison under VAMAS (TWA41) as preparatory guidance for future standardisation at ISO.
T2 - ISO/TC 229 Nanotechnologies Plenary Meeting - Graphene Standardisation
CY - Teddington, UK
DA - 14.11.2022
KW - Graphene oxide flakes
KW - SEM
KW - Morphology
KW - VAMAS
KW - Standardisation
KW - Sample preparation
KW - ISOGScope
PY - 2022
AN - OPUS4-56300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Measurement of Lateral Size of Graphene Oxide Flakes by SEM - An Update of the VAMAS TWA 41 Project P13
N2 - The progress of the VAMAS interlaboratory comparison Project P13 "Lateral size of graphene oxide flakes by SEM" within the Technical Working Area 41 "Graphene and Related 2D Materials" is presented. The challenges at sample preparation on substrates for accurate measurement and image analysis as well as two different analysis approaches, containing exact guidance how to measure the main descriptors for the lateral size measurement of the imaged graphene oxide flakes with Scanning Electron Microscopy are highlighted. The implementation of the results into the corresponding ISO technical specification AWI/TS 23879 is also discussed and planned, in relation with the AFM part.
T2 - The 32nd ISO/TC 229 IEC/TC 113 JWG2 General Meeting
CY - Berlin, Germany
DA - 06.11.2023
KW - VAMAS
KW - ISO/TC 229 Nanotechnologies
KW - Interlaboratory comparison
KW - Graphene oxide flakes
KW - SEM
PY - 2023
AN - OPUS4-58813
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Matthews, Lauren
T1 - Rapid Desease Monitoring with Resistive-Pulse Sensing in Nanopipettes
N2 - Following parts of the research project as proceeded at University of Birminngham are presented: Translocation, Experiments, Synthesis of DNA Structures, Antibody, Biomarker, Binding. Following works have been carried out at BAM: High Resolution Electron Microscopy, Dedicated Sample Preparation, Surface Analysis Methods.
T2 - UoB-BAM Chemistry Theme Meeting
CY - Online meeting
DA - 15.05.2024
KW - Nanopipettes
KW - Sensing
KW - Diagnosis
KW - Surface analysis
PY - 2024
AN - OPUS4-60451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Ongoing International Interlaboratory Comparisons on Size, Shape and (Relative) Concentration of Complex Nanoparticles under the Pre-Standardization Platform of VAMAS
N2 - Traceable morphological and chemical characterization of nanomaterials with respect to the various possible sizes, size distributions, shapes, and concentrations of real-world nanoparticles (NPs) is a challenging task. Particularly for the nonspherical, non-monodisperse nanoparticles – as typically for most of the commercial particles, including their strong tendency to agglomerate, there is a lack of standard operation procedures providing accurate nanoparticle characterisation.
In the framework of the pre-standardisation framework of VAMAS (Versailles Project on Advanced Materials and Standards, www.vamas.org) two interlaboratory comparison (ILC) studies are being carried out under the Technical Working Area (TWA) 34 “Nanoparticle Populations”:i) Project #15 addresses the analysis of the size and shape distribution of TiO2 bipyramidal NPs by traceable imaging methods such as TEM, SEM, STEM-in-SEM, AFM as well as with SAXS as an ensemble method. This ILC is thought as the next level development of the case studies exemplified in the published ISO standards ISO 21363 and ISO 19749. It was agreed to complete the first ILC with the NPs already prepared according to the same procedure on a TEM grid, and, at a later stage, to carry out second ILCs with the same NPs distributed to the participants as liquid suspensions together with protocols for the uniform NP deposition on suited substrates - as developed and optimized within the European project nPSize. Once having good deposition protocols available, the door for automated image analysis gets opened. Corresponding image analysis protocols and reporting templates have been distributed to the ILC participants, too.
ii) Project #16: two spherical SiO2 NP samples with bi-modal size distributions in two nominal relative number concentrations were prepared and distributed also as liquid suspensions accompanied by sample preparation, measurement, and image analysis protocols and reporting templates. Here, the NP concentration is the primary parameter to be measured. For the imaging methods it is targeted to
measure the relative nanoparticle concentrations (relative populations of the two modes).
The results of all the participating laboratories, in both ILCs, compiled in comparative representations will be shown and discussed for the first time. The reduction of the measurement uncertainties associated to the size, shape and number-concentration results induced by the significant improvement of the sample preparation on substrates (as single particles with a high-density coverage), combined with well-defined image analysis procedures will be highlighted.
Finally, a very recent 3rd ILC an the determination of lateral size of Graphene Oxide flakes by SEM is presented as project P13 under VAMAS TWA41 Graphene and Related 2D.
T2 - Microscopy and Microanalysis 2024
CY - Cleveland, OH, USA
DA - 28.07.2024
KW - VAMAS
KW - Interlaboratory comparison
KW - Imaging
KW - Nanoparticles
KW - Electron microscopy
KW - Graphene oxide
KW - Particle size distribution
PY - 2024
AN - OPUS4-60875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Physical-chemical Characterization of Graphene-Related 2D Materials: Development of Approaches for Reliable Quantification
N2 - An accurate characterisation of the morphological, structural, and chemical properties of nano and advanced materials is key for the understanding of the material functionality and constitutes the basis for future optimisation or even prediction of the product performance. Further, the correlation of the physical-chemical properties with results from biological testing leads to an understanding of the potential toxicological effects so that a minimisation of the materials risks becomes possible.
The presentation will highlight with examples the importance of the selection of the relevant parameters/descriptors and particularly their measurement for the reliable characterisation of the morphology, structure, and chemistry of graphene-related 2D-materials (GR2M’s) [1-3]. One crucial aspect is also one of most challenging ones in the characterisation chain: the proper sample preparation, which shall be tailored to the accurate measurement of the defined analytical parameter. Practical examples of measurement of morphological descriptors of GR2M’s, such as equivalent circular diameter (ECD), minimum and maximum Feret, and aspect ratio with electron microscopy, or of the thickness with atomic force microscopy (AFM) will be showed, together with quantitative chemical characterisation with X-ray photoelectron spectroscopy (XPS) and, newly, with energy-dispersive X-ray spectroscopy with a scanning electron microscope (SEM/EDX) [4] by evaluating accurately the elemental content as the ratio of O/C and the composition of impurities.
Another relevant, but challenging part of the characterisation of GR2M’s, particularly as the final products containing mostly low amounts of GR2M’s, is the analysis of homogeneity of the chemical composition by sensitive imaging methods. Examples of successful analysis with secondary ion mass spectrometry (SIMS), even if not quantitative, will be showed.
T2 - SaferWorldbyDesign Webinars
CY - Online meeting
DA - 25.03.2025
KW - Graphene-related 2D materials
KW - Standardisation
KW - Interlaboratory comparison
KW - Physico-chemical characterisation
PY - 2025
UR - https://saferworldbydesign.com/webinars/
AN - OPUS4-62791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Quantitative EDS analysis on graphene related 2D materials
N2 - The elemental analysis of solid matter by means of the Energy-Dispersive X-Ray Spectrometry (EDS) is meanwhile posible as a quick (seconds!) and more and more accurate analysis via standardsless (instantaneous) quantification. The sensitivity & quantification accuracy for light elements (C, O,..) has significantly increased in the recent years. The availability via table-top SEMs with incorporated EDS is also enhanced.
Further, the EDS analysis at an SEM is well-standardized, see ISO/TC 202 Microbeam Analysis & VAMAS/ TWA 37 Quantitative Microstructural Analysis in good liaisonships with ISO/TC 229 Nanotechnologies.
It is demostrated that key parameters such as oxygen-to-carbon atomic-% ratio and impurities can be realibly measured, with XPS as a reference method. Various EDS spectrometers and analysis conditions are tested and the validity of the EDS quantification of an ionic liquid of well-defined chemical composition is demonstrated.
Next steps are to launch a corresponding VAMAS interlaboratory comparison and to discuss within ISO/TC 229 towards inclusion of EDS as a routine method for the elemental analysis of GR2M into the ISO/TS 23359 Nanotechnologies — Chemical characterization of GR2Ms in powders and suspensions.
T2 - Annual Microscopy Community Meeting for the National Research Council in Canada
CY - Online meeting
DA - 18.11.2025
KW - Graphene-related 2D materials (GR2M)
KW - Elemental analysis
KW - Light elements
KW - SEM/EDS
KW - Standardisation
PY - 2025
AN - OPUS4-64766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chemello, Giovanni
T1 - Correlative analysis through XPS and EDX measurements for accurate chemical composition of industrial Graphene
N2 - The scientific and technological interest in graphene has been growing more and more in the late years due to its outstanding properties and diverse promising applications. However, graphene implementation into the industrial market is still limited and many challenges are yet to be addressed before this material can become suitable for the large-scale production. One of the most crucial challenge to overcome is to develop reliable and reproducible ways to characterize the material properties which can heavily affect the product performance. In our study the chemical composition of nine different samples of industrial graphene, graphene oxide and functionalized graphene were investigated. The samples were analysed both in form of powder and pellets. A comparative characterisation of the chemical composition was performed through X-ray Photoelectron Spectroscopy (XPS) and Energy Dispersive X-ray Spectroscopy (EDX). XPS depth resolution is in the order of 10 nm, while for EDX the analysis was performed at two different energy levels, i.e. 5 keV and 15 keV, and thus varying the analysis depth from 200 nm to 2000 nm. The XPS measurement area is 300x700 µm² while the EDX measurement was performed by analysing a grid of 25 locations (5x5) of 150 x 150 ?m2 area, covering the whole pellet surface of 5 mm diameter and then calculating the mean of the elemental concentration. The results of the elemental concentration values from XPS and EDX analyses show a good agreement for all the elements presents in the samples, despite the different spatial resolutions of the two techniques. Therefore, the samples appear homogeneous both in the lateral and vertical directions. The results relative to powder and pellets samples do not differ in a significant way except for a slight increase in the carbon content regarding the pellet samples, probably due to a minor contamination effect introduced through pressing. Nevertheless, pellets samples appear to be quite representative for the material while being much more convenient in terms of handling and safety compared to nano-powders and providing a regular flat surface for EDX analysis. Finally, this approach correlating XPS and EDS represents a simple, fast and reliable way for characterizing the chemical composition and the homogeneity of industrial graphene. This study is part of the project ?Standardisation of structural and chemical properties of graphene? (ISO-G-SCoPe) which has received funding from the EMPIR programme co-financed by the Participating States and from the European Union?s Horizon 2020 research and innovation programme under Grant agreement No. 19NRM04.
T2 - 2021 Fall Meeting of the European Materials Research Society (E-MRS)
CY - Online meeting
DA - 20.9.2021
KW - Graphene
KW - XPS
KW - EDS
KW - Standardisation
KW - Graphene functionalization
PY - 2021
UR - https://www.european-mrs.com/meetings/2021-fall-meeting
AN - OPUS4-53462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Reliable chemical characterization of industrial graphene related materials
N2 - International standards describing reliable protocols will facilitate the commercialization of graphene and related 2D materials. One physico-chemical key property next to flake size and thickness is the chemical composition of the material. Therefore, an ISO standard is under development with X-ray photoelectron spectroscopy having a prominent role. With its information depth of around 10 nm which is the similar length scale as the thickness as of particles of 2D materials consisting of a few monolayer XPS seems to be highly suitable for this purpose. Different sample preparation methods like pressing the powders onto adhesive tapes, into recesses, or into solid pellets result in inconsistencies in the quantification. For the validation of the quantification with XPS an interlaboratory comparison was initiated under the auspice of the “Versailles Project on Advanced Materials and Standards” (VAMAS). First results confirm that the sample preparation method (pellet vs. powder) influences the quantification results clearly. Considering this effect, a good agreement of the results from the different participants were observed. Similar results were observed for raw, N- and F-functionalized graphene.
T2 - Graphene
CY - Manchester, England, UK
DA - 27.06.2023
KW - X-ray photoelectron spectroscopy
KW - Functionalized graphene
KW - Interlaboratory comparison
KW - VAMAS
PY - 2023
AN - OPUS4-57895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Measurement of Lateral Dimensions of Particles & Flakes (2D) by Imaging Methods
N2 - An overview with the basics of size and shape measurement of particles and 2D structures according to established methodologies (and popular imaging processing software packages) with imaging techniques is given. Main descriptors are explained based on practical cases are determined interactively at the flipchart.
T2 - MaterialsWeek 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Nanoparticles
KW - 2D materials
KW - Lateral dimensions
KW - ISO
KW - Imaging
PY - 2024
AN - OPUS4-60454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative Morphological-Chemical Imaging of Nanostructured Materials
N2 - Newly developed methodical approaches with an emphasis on correlative imaging analysis of morphology and chemistry of nanomaterials will be presented. Correlative imaging by high-resolution SEM with STEM-in-SEM as well as with EDS, and further with AFM, or with the new technique TKD (Transmission Kikuchi Diffraction) will be explained on various examples of nanostructures, both as starting materials and as embedded/functionalized nanoparticles in products. The unique analytical benefits of the Auger electron probe as a veritable nano-tool for the local surface chemistry will be highlighted. Examples of hybrid analysis of the bulk of nanomaterials by X-ray Spectroscopy and the highest surface-sensitive methods XPS and ToF-SIMS as advanced surface characterization methods available in the Competence Centre nano@BAM will be showed. Particularly for the spatially resolved analysis of the chemistry of nanostructures, such in-depth and lateral gradients of chemistry within mesoporous thin layers, or the completeness of the shells of core-shell nanoparticles, the latter methods are inherent.
Other dedicated developments like approaches for the quantitative determination of the porosity of thin mesoporous layers by electron probe microanalysis (EPMA) with SEM or the quantitative determination of the roughness of particle surface by high-resolution imaging with electron microscopy will be also presented.
T2 - Conference on Applied Surface and Solid Material Analysis AOFKA 2023
CY - Zurich, Switzerland
DA - 11.09.2023
KW - Correlative imaging
KW - Electron microscopy
KW - X-ray spectroscopy
KW - Nanostructures
PY - 2023
UR - https://aofka23.scg.ch/
AN - OPUS4-58338
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative imaging analysis of non-spherical nanoparticles
N2 - It sounds like being a simple analytical task, it is definitely not. The way toward accurate measurement of the size distribution of nanoparticles (NPs) with complex shape, having a broad size polydispersity, with inhomogeneous chemistry, and with a high degree of agglomeration/aggregation is very challenging for all available analytical methods. Particularly for the NPs with complex shape, the access to the smallest dimension (as e.g. required for regulatory purposes) can be enabled only by using imaging techniques with spatial resolution at the nanoscale. Moreover, the full 3D-chacterisation of the NP shape can be provided either by advanced characterization techniques like 3D-TEM tomography or by correlative analysis, i. e. synergetic/complementary measurement of the same field-of-view of the sample with different probes. Examples of the latter type of analysis are: i) electron microscopy for the lateral dimensions and AFM for the height of the NPs, ii) SEM with STEM-in-SEM (also called T-SEM), iii) Electron Microscopy with TKD (Transmission Kikuchi Diffraction) for determination of the geometrical orientation of crystalline NPs, iv) Raman and SEM for e.g. thickness of graphen flakes, or v) Electron Microscopy for descriptive NP shape and SAXS for the NP concentration, the latter as a NP property able to be measured with higher and higher accuracy. For all these types of measurement, reference NPs are necessary for the validation of the measured size. Particularly non-spherical reference NPs are still missing. Examples of such new reference NPs as characterized by the correlative analyses enumerated above will be presented in detail in the contribution.
T2 - 2021 Fall Meeting of the European Materials Research Society (E-MRS)
CY - Online meeting
DA - 20.9.2021
KW - Nanoparticles
KW - Transmission Kikuchi Diffraction (TKD)
KW - Correlative imaging
KW - Electron microscopy
KW - AFM
KW - TiO2
KW - VAMAS
PY - 2021
UR - https://www.european-mrs.com/meetings/2021-fall-meeting
AN - OPUS4-53367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, L. M.
A1 - Müller, J. T.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Schmidt, J.
A1 - Bekheet, M. F.
A1 - Gurlo, A.
A1 - Simon, U.
T1 - Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential
N2 - Mechanically stable structures with interconnected hierarchical porosity combine the benefits of both small
and large pores, such as high surface area, pore volume, and good mass transport capabilities. Hence, lightweight micro-/meso-/macroporous monoliths are prepared from ordered mesoporous silica COK-12 by means of spark plasma sintering (SPS, S-sintering) and compared to conventionally (C-) sintered monoliths. A multi-scale model is developed to fit the small angle X-ray scattering data and obtain information on the hexagonal lattice parameters, pore sizes from the macro to the micro range, as well as the dimensions of the silica population. For both sintering techniques, the overall mesoporosity, hexagonal pore ordering, and amorphous character are preserved. The monoliths' porosity (77–49%), mesopore size (6.2–5.2 nm), pore volume (0.50–0.22 g cm-3
), and specific surface area (451–180 m2 g-1) decrease with increasing processing temperature and pressure. While the difference in porosity is enhanced, the
structural parameters between the C-and S-sintered monoliths are largely converging at 900 C, except for the mesopore size and lattice parameter, whose dimensions are more extensively preserved in the
S-sintered monoliths, however, coming along with larger deviations from the theoretical lattice. Their higher mechanical properties (biaxial strength up to 49 MPa, 724 MPa HV 9.807 N) at comparable porosities and ability to withstand ultrasonic treatment and dead-end filtration up to 7 bar allow S-sintered monoliths to reach a high permeance (2634 L m-2 h-1 bar-1), permeability (1.25 x 10^-14 m2), and ability to reduce the chemical oxygen demand by 90% during filtration of a surfactant-stabilized oil in water emulsion, while indicating reasonable resistance towards fouling.
KW - SAXS
KW - Hierarchically porous
KW - Silica
KW - Water filtration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555928
DO - https://doi.org/10.1039/D2NA00368F
SN - 2516-0230
SP - 1
EP - 17
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-55592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
T1 - Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical concentration by Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the work is to quantitatively measure the chemical composition in the weld seam of various DSS and to identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material. Spectra were recorded every 1.3 s at a spacing of approximately 2 mm. During the cooling process the location of the measurement was not changed. The LIBS method is proofed to be suitable for the quantitative representation of the chemical compositions during the welding process.
T2 - ICASP-6
CY - Le Bischenberg, France
DA - 20.06.2022
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Evaporation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571308
DO - https://doi.org/10.1088/1757-899X/1274/1/012018
VL - 1274
SP - 1
EP - 8
PB - IOP Publishing
CY - Bristol
AN - OPUS4-57130
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - D'Accardi, E.
A1 - Ulbricht, Alexander
A1 - Krankenhagen, Rainer
A1 - Palumbo, D.
A1 - Galietti, U.
T1 - Capability of active thermography to detect and localize pores in Metal Additive Manufacturing materials
N2 - Active thermography is a fast, contactless and non-destructive technique that can be used to detect internal defects in different types of material. Volumetric irregularities such as the presence of pores in materials produced by the Additive Manufacturing processes can strongly affect the thermophysical and the mechanical properties of the final component.
In this work, an experimental investigation aimed at detecting different pores in a sample made of stainless AISI 316L produced by Laser Powder Bed Fusion (L-PBF) was carried out using pulsed thermography in reflection mode. The capability of the technique and the adopted setups in terms of geometrical and thermal resolution, acquisition frequency and energy Density of the heating source were assessed to discern two contiguous pores as well as to detect a single pore. Moreover, a quantitative indication about the minimum resolvable pore size among the available and analysed defects was provided. A powerful tool to assess the Limits and the opportunities of the pulsed technique in terms of detectability and localizability was provided by comparing active thermography results to Computed Tomography as well as a related Finite Element Analysis (FEA) to simulate the pulsed heating transfer with Comsol.
T2 - 49th Italian Association for Stress Analysis Conferencee (AIAS 2020)
CY - Online meeting
DA - 02.09.2020
KW - Additive manufacturing
KW - Laser powderbed fusion
KW - Pores
KW - Thermography
KW - Micro-CT
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519231
DO - https://doi.org/10.1088/1757-899X/1038/1/012018
VL - 1038
SP - 1
EP - 17
PB - Institute of Physics
CY - London
AN - OPUS4-51923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - How to run a (lab) SAXS instrument efficiently
N2 - Here I talk about our holistic approach to X-ray scattering, and what improvements we made to our methodology to make measuring with us a very streamlined process.
KW - Laboratory management
KW - MOUSE
KW - X-ray scattering
KW - Instrument utilization
KW - Research efficiency
KW - Automation
KW - Metadata collection
KW - Laboratory automation
PY - 2022
UR - https://www.youtube.com/watch?v=ncadUQ43Uwc
DO - https://doi.org/10.26272/opus4-55761
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-55761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Maack, Stefan
A1 - Bertovic, Marija
A1 - Radtke, Martin
A1 - et al.,
ED - Wahlster, W.
ED - Winterhalter, C.
T1 - Deutsche Normungsroadmap künstliche Intelligenz
N2 - Rund ein Jahr haben DIN und DKE in einem gemeinsamen Projekt mit dem Bundesministerium für Wirtschaft und Energie und zusammen mit ca. 300 Fachleuten aus Wirtschaft, Wissenschaft, öffentlicher Hand und Zivilgesellschaft an der Normungsroadmap Künstliche Intelligenz gearbeitet. Eine hochrangige Steuerungsgruppe unter dem Vorsitz von Prof. Wolfgang Wahlster hat die Erarbeitung koordiniert und begleitet.
Ziel der Roadmap ist die frühzeitige Entwicklung eines Handlungsrahmens für die Normung und Standardisierung, der die internationale Wettbewerbsfähigkeit der deutschen Wirtschaft unterstützt und europäische Wertmaßstäbe auf die internationale Ebene hebt.
KW - Künstliche Intelligenz
KW - Normung
KW - Roadmap
PY - 2020
UR - https://www.din.de/resource/blob/772438/ecb20518d982843c3f8b0cd106f13881/normungsroadmap-ki-data.pdf
VL - 2020
SP - 1
EP - 232
PB - Deutsches Institut für Normung (DIN)
CY - Berlin
ET - 1.
AN - OPUS4-51733
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - The versatility of X-ray absorption spectroscopy (XAS) for exploring new materials in collaborative research
N2 - With increasing demand and environmental concerns, researchers are exploring new materials that can perform as well or better than traditional materials while reducing environmental impact. X-ray absorption spectroscopy (XAS) enables unique atom-specific tool to probe the electronic structure of materials. The BAM plays a central role in this highly collaborative research. The BAMline, a real-life sample materials research beamline, at the Berlin Synchrotron BESSY-II, provides unique insights into materials’ electronic and chemical structure at different time and length scales. This enables real-time optimization of material properties and performance for various applications, such as energy storage and conversion, catalysis, and corrosion resistance. This talk provides an overview of the analytical methods and sample environments of the BAMline and addresses its potential for further advances in sustainable materials research.
T2 - International symposium of radiation physics (ISRP-16)
CY - Lisbon, Portugal
DA - 01.09.2024
KW - XAS
KW - Time-resolved studies
KW - Operando
KW - Corrosion
KW - Electrochemistry
PY - 2024
AN - OPUS4-60996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Bridging Structure and Electronic State: Real-time XES–XRD Fusion for Functional Alloys
N2 - We present a unified X-ray Emission Spectroscopy (XES) and X-ray Diffraction (XRD) approach for real-time, in situ characterization of materials, demonstrated on Co₂FeSi Heusler alloys under varied heat treatments. The combination of XES and XRD is particularly well-suited to Heusler alloys, where subtle changes in atomic ordering and electronic structure (e.g. site occupancy, hybridization, and spin state) are tightly interdependent and critical for their magnetic and transport properties. In addition, this method enables more efficient materials design by reducing experimental iterations through comprehensive structural and electronic analysis. Developed at the mySpot beamline at BESSY-II, the platform integrates (a) digital twin-based experiment planning, (b) open-source XES spectral simulations, (c) an optimized single-shot, two-element XES setup with sub-pixel resolution for enhanced energy precision, and (d) result-driven beamtime utilization. With an unprecedented synchronized XES-XRD platform, we aim to shed light on how diffusion-controlled processes in Heusler alloys and double perovskites at elevated temperatures establish the formation of specific phases with distinct structure types in real time. This, in turn, strongly impacts the functional properties of the materials under scrutiny.
T2 - XLIV Colloquium Spectroscopicum Internationale
CY - Ulm, Germany
DA - 27.07.2025
KW - Multimodal
KW - X-ray spectroscopy
KW - X-ray diffraction
KW - Functional alloys
PY - 2025
AN - OPUS4-63991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - da Silva, T. R.
A1 - Matos, P. R. de
A1 - Durlo Tambara, Luís Urbano
A1 - Marvila, M. T.
A1 - de Azevedo, A. R. G.
T1 - A review on the performance of açaí fiber in cementitious composites: Characteristics and application challenges
N2 - This paper aimed to perform an exploratory literature review, focusing on the aspects of hydration and rheological properties of cementitious composites with açaí fibers. The use of natural fibers as a reinforcement in cementitious matrices has been widely studied, and açaí fiber is a promising option due to its unique characteristics. However, there is still a lack of knowledge regarding the correlation between fiber parameters and the technological properties of composites, which limits the development of new applications, such as 3D printing. The review provided an overview of the main characteristics of açaí fibers and the parameters for their application in cementitious matrices. Alkali treatment with 5% NaOH solution for 1 h shows increased mechanical and physical properties in açaí fibers. Despite the potential advantages of these composites, they pose challenges due to the different fiber surface treatment and interfacial transitions and the processing conditions of the fibers. Although small addition of açaí fibers slightly decreases the cement hydration process, keeping the cross-compatibility index high (>95). To overcome these challenges, it is necessary to evaluate the rheological behavior of cementitious materials with açaí fibers, which has not been reported in the literature. By doing so, it will be possible to optimize the processing conditions and develop new applications, such as additive manufacturing, which has never been explored with açaí fibers.
KW - Natural fibers
KW - Açaí fiber
KW - Portland cement
KW - Alternative materials
PY - 2023
DO - https://doi.org/10.1016/j.jobe.2023.106481
SN - 2352-7102
VL - 71
IS - 106481
SP - 1
EP - 21
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-57326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Studies of high-entropy alloys using x-ray absorption fine structure at the bamline
N2 - BAM line is multipurpose high-energy beamline. To extend studies of multicomponent alloys using EXAFS we perform own research and user experiments requiring multiedge spectroscopy, high-temperature and chemically aggressive sample environments. Our study of multicomponent alloys and high-entropy alloys open new perspectives in understanding their reactivity, corrosion, phase transformations and local ordering.
T2 - SPP2006: large scale facilities
CY - Online meeting
DA - 02.11.2021
KW - Synchrotron studies
KW - High-entropy alloys
KW - EXAFS
PY - 2021
AN - OPUS4-54016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Durlo Tambara, Luís Urbano
A1 - Matos, P. R. de
A1 - Lima, G. T. S.
A1 - Silvestro, L.
A1 - Rocha, J.C.
A1 - Campos, C. E. M. de
A1 - Gleize, P. J. P.
T1 - Influence of Nanosilica and Superplasticizer Incorporation on the Hydration, Strength, and Microstructure of Calcium Sulfoaluminate Cement Pastes
N2 - This study investigated the effect of incorporating three types of nanosilica (NS), two powders, and one colloidal suspension on the hydration, strength, and microstructure of calcium sulfoaluminate (CSA) cement pastes prepared with and without a superplasticizer (SP). X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and compressive strength tests were performed after 2, 5, and 28 days of hydration. The results showed that both NS powders delayed cement hydration at an early age, which was attributed to particle agglomeration (confirmed by dynamic light scattering). Whereas well-dispersed colloidal NS did not significantly affect the hydration of CSA at the investigated ages. SP incorporation improved the dispersion of CSA cement particles, resulting in a 10% increase in the degree of hydration of ye’elimite at 28 days for the system without NS. Conversely, when the SP was incorporated in NS-containing mixtures, it hindered cement hydration of the systems with powdered NS, but did not significantly affect the cement hydration of the system containing colloidal NS. The SEM images suggested that the SP changed the ettringite morphology, thereby negatively affecting the mechanical strength of the CSA pastes.
KW - Calcium sulfoaluminate (CSA) cement
KW - Nanosilica (NS)
KW - Hydration
KW - Microstructure
PY - 2023
DO - https://doi.org/10.1061/JMCEE7.MTENG-15570
SN - 0899-1561
VL - 35
IS - 7
SP - 04023216
PB - ASCE
AN - OPUS4-57404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruna, F. G.
A1 - Prokop, M.
A1 - Bystron, T.
A1 - Loukrakpam, R.
A1 - Melke, J.
A1 - Lobo, C. M. S.
A1 - Fink, M.
A1 - Zhu, M.
A1 - Voloshina, E.
A1 - Kutter, M.
A1 - Hoffmann, H.
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, B.
A1 - Bouzek, K.
A1 - Paulus, B.
A1 - Roth, C.
T1 - Following adsorbed intermediates on a platinum gas diffusion electrode in H3PO3‑containing electrolytes using in situ X‑ray absorption spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalyst with H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - Δμ XANES
KW - H3PO3
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - ACS
CY - Washington, DC
AN - OPUS4-55815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lutz, C.
A1 - Hampel, S.
A1 - Ke, X.
A1 - Beuermann, S.
A1 - Turek, T.
A1 - Kunz, U.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Fittschen, U.
T1 - Evidence for redox reactions during vanadium crossover inside the nanoscopic water-body of Nafion 117 using X-ray absorption near edge structure spectroscopy
N2 - A major source of capacity fade of the common vanadium redox flow battery (VRFB) is the vanadium ion transport through the separator. However, different transport models disagree significantly in the diffusion coefficient for the different V species and the influence of different transport mechanisms. The underlying hypothesis of this work is that reactions inside the membrane are partly responsible for these discrepancies. Accordingly, it was investigated if redox reactions inside the nanoscopic water body of Nafion 117 can occur. X-ray absorption near edge structure spectroscopy (XANES) was used to distinguish between the different V species inside hydrated Nafion 117 and novel PVDF-based membranes. It was validated that the speciation of vanadium can be performed using the pre-edge peak energy and intensity. The experiments were performed as follows: strips of the membrane were exposed from one site to a V3+ solution (green) and from the other site to a VO2+ solution (yellow). The ions could diffuse into the membrane from both sides. A change of color of the membrane strip was observed. The blue color in the middle of the strip indicated that VO2+ was formed where V3+ and VO2+ got in contact. Using XANES this reaction inside Nafion was proven.
KW - PVDF-Based membrane
KW - VRFB
KW - Vanadium speciation
KW - XANES
KW - Nafion 117
PY - 2020
DO - https://doi.org/10.1016/j.jpowsour.2020.229176
VL - 483
SP - 229176
PB - Elsevier B.V.
AN - OPUS4-51719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grengg, C.
A1 - Koraimann, G.
A1 - Ukrainczyk, N.
A1 - Rudic, O.
A1 - Luschnig, S.
A1 - Gluth, Gregor
A1 - Radtke, Martin
A1 - Dietzel, M.
A1 - Mittermayr, F.
T1 - Cu- and Zn-doped alkali activated mortar – Properties and durability in (bio)chemically aggressive wastewater environments
N2 - Metakaolin-based alkali activated mortars (AAM) - with and without CuSO4·5H2O and ZnO addition (mass ratio Mn+/solid binder 0.08% to 1.7%) - were casted and exposed within an extensive long-term field campaign over the period of 20 months to a sewer basin, strongly affected by biogenic acid corrosion. (Un-)exposed AAM were tested regarding their physicochemical and microstructural properties, bioreceptivity and overall durability. Metal addition led to a retarding effect during alkali-activation reaction, as well as to an increase in open porosity of up to 3.0% and corresponding lower compressive strength of up to 10.9%. Reduced microbial colonization and diversity were observed on AAM with Cu, while Zn addition led to increased biodiversity. We propose that the observed higher durability of Cu-doped AAM is due to antibacterial effects and associated reduction of biogenic acid production, superseding overall negative effects of metal-dosage on physical material properties. Observed lower durability of Zn-doped AAM was related to combined negative physicochemical and microbial effects.
KW - Microbially induced corrosion
KW - Alkali-activated materials
KW - Biogenic acid corrosion
KW - Biogene Schwefelsäurekorrosion
KW - MIC
PY - 2021
DO - https://doi.org/10.1016/j.cemconres.2021.106541
SN - 0008-8846
VL - 149
SP - 1
EP - 15
PB - Elsevier
CY - Oxford
AN - OPUS4-53070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Liu, Yanchen
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Alippi, Paola
A1 - Lee, Kug-Seung
A1 - Jeon, Taeyeol
A1 - Weißer, Kilian
A1 - Karlsen, Martin A.
A1 - Russo, Patrícia A.
A1 - Pinna, Nicola
T1 - FeNb2O6 as a high-performance anode for sodium-ion batteries enabled by structural amorphization coupled with NbO6 local ordering.
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes materials for lithium-ion batteries. Currently, they are also emerging as promising anodes for sodium-ion batteries due to their low volume change and safety. However, the potential electrochemical performance in sodium energy storage is not fully achieved, primarily due to the larger radius of the Na+-ions. Here, we report for the first time an iron niobate with columbite structure as a high-performance sodium storage anode. The presence of iron in the structure is vital to trigger the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible Na storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ insertion and extraction, as demonstrated through operando and ex-situ characterizations. It leads to an applicable reversible capacity ( 300 mAh g-1) with a favorable average voltage of ca. 0.6 V and excellent rate capability (180.4 mAh g-1 at a current density of 2 A g-1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - XAS
KW - Sodium-Ion-Batteries
KW - In-situ
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631159
DO - https://doi.org/10.26434/chemrxiv-2025-2gn7z
SP - 1
EP - 51
PB - American Chemical Society (ACS)
AN - OPUS4-63115
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lin, R.
A1 - Li, X.
A1 - Krajnc, A.
A1 - Li, Z.
A1 - Li, M.
A1 - Wang, W.
A1 - Zhuang, L.
A1 - Smart, S.
A1 - Zhu, Z.
A1 - Appadoo, D.
A1 - Harmer, J. R.
A1 - Wang, Z.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Beyer, S.
A1 - Wang, L.
A1 - Mali, G.
A1 - Bennett, T. D.
A1 - Chen, V.
A1 - Hou, J.
T1 - Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal–Organic Framework Glasses for the Oxygen Evolution Reaction
N2 - The melting behaviour of metal–organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through meltquenching of the cobalt-based zeolitic imidazolate Framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62-(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching. The resultant Co–Fe bimetallic MOF glass therefore shows a significantly enhanced oxygen evolution reaction performance. The novel bimetallic MOF glass, when combined with the facile and scalable mechanochemical synthesis technique for both discrete powders and surface coatings on flexible substrates, enables significant opportunities for catalytic device Assembly
KW - Electrodes
KW - MOF
KW - OER
KW - XANES
KW - XAS
KW - Bimetallic frameworks
PY - 2022
DO - https://doi.org/10.1002/anie.202112880
VL - 61
IS - 4
SP - e202112880
PB - Wiley
AN - OPUS4-54018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - The versatility of XAS@BAM for real-time in situ electrocatalysis in collaborative materials research
N2 - With the global push toward sustainable energy technologies, the development of efficient and durable electrocatalysts has become a research priority. Real-time in situ studies are essential to understand the dynamic behavior of catalysts under operational conditions. X-ray absorption spectroscopy (XAS) offers a unique, element-specific probe of electronic and structural changes at the active sites of electrocatalysts during electrochemical reactions.
At BAM, collaborative research efforts leverage the advanced capabilities of the BAMline at the Berlin Synchrotron BESSY-II to study electrocatalytic materials under realistic working conditions. As a dedicated materials research beamline, the BAMline enables in situ and operando XAS across different time and length scales, making it ideally suited for monitoring catalytic transformations in real time.
This presentation highlights the analytical strengths and sample environments developed for electrochemical cells at BAM, showcasing their application to electrocatalysis for energy conversion (e.g., water splitting, CO₂ reduction). Emphasis will be placed on how these insights contribute to the rational design and real-time optimization of functional materials for a sustainable energy future.
T2 - MATSUS Konferenz
CY - Valencia, Spanien
DA - 20.10.2025
KW - Operando
KW - XAS
KW - In situ
KW - Electrocatalysis
PY - 2025
AN - OPUS4-64493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qureshi, Navid
A1 - Morrow, Ryan
A1 - Eltoukhy, Samar
A1 - Grinenko, Vadim
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Onykiienko, Yevhen A.
A1 - Kulbakov, Anton
A1 - Inosov, Dmytro S.
A1 - Adler, Peter
A1 - Valldor, Martin
T1 - Noncollinear Magnetic Structures in the Chiral Antiperovskite β-Fe2SeO
N2 - We present the magnetic properties of the chiral, polar, andpossibly magnetoelectric antiperovskite β-Fe2SeO as derived from magnet-ization and specific-heat measurements as well as from powder neutrondiffraction and Mössbauer experiments. Our macroscopic data unambig-uously reveal two magnetic phase transitions at TN1 ≈ 103 K and TN2 ≈ 78K, while Rietveld analysis of neutron powder diffraction data reveals anoncollinear antiferromagnetic structure featuring magnetic moments inthe a−b plane of the trigonal structure and a ferromagnetic moment alongc. The latter is allowed by symmetry between TN1 and TN2, weakly visible inthe magnetization data yet unresolvable microscopically. While theintermediate phase can be expressed in the trigonal magnetic spacegroup P31, the magnetic ground state is modulated by a propagation vectorq = (1/2 1/2 0) resulting in triclinic symmetry and an even more complexlow-temperature spin arrangement which is also reflected in the Mö ssbauer hyperfine patterns indicating additional splitting of Fesites below TN2. The complex noncollinear spin arrangements suggest interesting magnetoelectric properties of this polar magnet.
KW - EXAFS
KW - Antiperovskite
KW - Magnetic structure
PY - 2024
DO - https://doi.org/10.1021/acs.inorgchem.4c02916
SN - 0020-1669
VL - 63
IS - 48
SP - 22712
EP - 22720
PB - American Chemical Society (ACS)
AN - OPUS4-63116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Abrudan, R.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schneider, M.
A1 - Laplanche, G.
A1 - Yusenko, Kirill
T1 - Inner relaxations in equiatomic single-phase high-entropy Cantoralloy
N2 - The superior properties of high-entropy multi-functional materials are strongly connected with their atomic heterogeneity through many different local atomic interactions. The detailed element-specific studies on a local scale can provide insight into the primary arrangements of atoms in multicomponent systems and benefit to unravel the role of individual components in certain macroscopic properties of complex compounds. Herein, multi-edge X-ray absorption spectroscopy combined with reverse Monte Carlo simulations was used to explore a homogeneity of the local crystallographic ordering and specific structure relaxations of each constituent in the equiatomic single-phase facecentered cubic CrMnFeCoNi high-entropy alloy at room temperature. Within the considered fitting approach, all five elements of the alloy were found to be distributed at the nodes of the fcc lattice without any signatures of the additional phases at the atomic scale and exhibit very close statistically averaged interatomic distances (2.54 – 2.55 Å) with their nearest-neighbors. Enlarged structural displacements were found solely for Cr atoms. The macroscopic magnetic properties probed by conventional magnetometry demonstrate no opening of the hysteresis loops at 5 K and illustrate a complex character of the long-range magnetic order after field-assisted cooling in ± 5 T. The observed magnetic behavior is assigned to effects related to structural relaxations of Cr. Besides, the advantages and limitations of the reverse Monte Carlo approach to studies of multicomponent systems like high-entropy alloys are highlighted.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
KW - X-ray absorption near edge structure (XANES)
PY - 2022
DO - https://doi.org/10.1016/j.jallcom.2022.165999
SN - 0925-8388
VL - 920
SP - 1
EP - 31
PB - Elsevier
AN - OPUS4-55457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yun, Tae Gyu
A1 - Chen, Boqiang
A1 - Wells, Sarah
A1 - Lim, Younghwan
A1 - Kim, Jun Seop
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Waegele, Matthias M.
A1 - Risch, Marcel
A1 - Grimaud, Alexis
ED - de Oliveira Guilherme Buzanich, Ana
T1 - Extrinsic and Intrinsic Factors Governing the Electrochemical Oxidation of Propylene in Aqueous Solutions
N2 - The electrochemical synthesis of commoditychemicals such as epoxides and glycols offers a sustainablealternative to conventional methods that involve hazardouschemicals. Efforts to improve the yield and selectivity of propyleneoxidation using Pd-based catalysts have been shown to be highlysensitive to applied potential, pH, and electrochemical cell design.Record efficiencies and yields were obtained by substitution ofPdO by 4d or 5d transition metals, including Pt, with thus far littlerationale regarding the origin for the improvement. Throughelectrochemical analysis, scanning transmission electron micros-copy, X-ray absorption spectroscopy, and surface-enhanced infraredabsorption spectroscopy, we investigated the mechanism ofpropylene oxidation on Pd-based catalysts. We demonstrate thatadsorbates forming on PdO, where Pd adopts a square-planar coordination [PdO4], differ from that forming on the surface ofoxidized metallic Pd catalysts with an oxo intermediate mediating propylene oxidation on PdO. We further show that Pt substitutionin PdO does not modify this oxo intermediate. Varying pH, we found that the onset for propylene oxidation is pH independent,indicating a potential-determining step where the proton is not involved in and similar reaction pathway in acidic and near-neutralconditions. Finally, our work undoubtedly demonstrates that high Faradaic efficiency toward propylene glycol and propylene oxideformation, such as those previously reported in the literature, can be achieved by means of electrode engineering and mastery ofmass transport and local pH. Notably, we achieved ≈100% faradaic efficiency for propylene glycol at 1.7 V vs RHE in acidic mediausing a Pt-substituted PdO catalyst loaded onto a gas diffusion electrode.
KW - XAS
KW - Electrochemistry
KW - Popylene oxidation
KW - 4d metals
PY - 2025
DO - https://doi.org/10.1021/jacs.5c02585
SN - 0002-7863
VL - 147
IS - 14
SP - 12318
EP - 12330
PB - American Chemical Society (ACS)
AN - OPUS4-63112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - The versatility of X-ray absorption spectroscopy (XAS) for exploring new materials in collaborative research
N2 - From Physics Engineer at FCUL in Lisbon to senior scientist at the Federal Institute for Materials Research and Testing (BAM) in Berlin, Germany. In this seminar, a personal journey using X-rays as a tool to probe different types of materials will be given. Examples of applications relevant to our society demonstrate how versatile and useful X-rays are
T2 - Forschungsseminar an der FCUL (Univesity of Lisbon)
CY - Online meeting
DA - 25.10.2024
KW - XAS
KW - Time-resolved studies
KW - Operando
KW - Corrosion
KW - Electrochemistry
PY - 2024
AN - OPUS4-61597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray absorption spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - Advances X ray Analytics Seminar at TU Berlin
CY - Berlin, Germany
DA - 14.06.2022
KW - XAS
KW - Mechanochemistry
KW - Time resolved
KW - In situ
PY - 2022
AN - OPUS4-56259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Flatken, M. A.
A1 - Radicchi, E.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Härk, E.
A1 - Pascual, J.
A1 - Mathies, F.
A1 - Shargaieva, O.
A1 - Prause, A.
A1 - Dallmann, A.
A1 - De Angelis, F.
A1 - Hoell, A.
A1 - Abate, A.
T1 - Role of the Alkali Metal Cation in the Early Stages of Crystallization of Halide Perovskites
N2 - ABX3 metal halide perovskites revolutionized the research and development of new optoelectronics, including solar cells and light-emitting diodes. Processing polycrystalline thin films from precursor solutions is one of the core advantages of these materials since it enables versatile and cost-effective manufacturing. The perovskite film morphology, that is, continuous substrate coverage and low surface roughness, is of paramount importance for highly efficient solar cells and optoelectronic devices in general. Controlling the chemistry of precursor solutions is one of the most effective strategies to manage the perovskite film morphology. Herein, we show the fundamental influence of the A-site cation composition on the perovskite precursor arrangement and the consequent film formation. Extended X-ray absorption fine structure spectroscopy and small-angle X-ray scattering give unprecedented insights into the complex structural chemistry of the perovskite precursors and, in particular, their repulsive interactions as a crucial parameter for colloidal stability. Combining these techniques with in situ grazing incidence wide-angle X-ray scattering during thin-film formation allows us to identify the mechanism for using alkali metals as a decisive criterion to control the colloidal stability of the perovskite precursor and thus the thin-film morphology. We illustrate the fundamental principle behind the systematic use of alkali metals regardless of whether they are incorporated in the lattice or not. Hence, this work provides tools to selectively control the morphology and crystal growth in present and future systems
KW - MAPbI3 perovskites
KW - Halide Perovskites
KW - X-ray absorption spectroscopy
PY - 2022
DO - https://doi.org/10.1021/acs.chemmater.1c03563
SN - 0897-4756
VL - 34
IS - 3
SP - 1121
EP - 1131
PB - American Chemical Society
AN - OPUS4-54713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Risse, Kerstin
A1 - Nikiforidis, Constantinos V.
A1 - Morris, Imogen
A1 - Thünemann, Andreas
A1 - Drusch, Stephan
T1 - Regulating the heat stability of protein-phospholipid stabilised oil-water emulsions by changing the phospholipid headgroup or fatty acyl chain
N2 - Stabilising oil–water emulsions remains a central challenge across food, pharmaceutical and cosmetic applications. β-lactoglobulin (β-LG) and phospholipids (PLs) can act synergistically at oil-water interfaces: PLs adsorb rapidly, while β-LG forms a viscoelastic protein network that enhances long-term stability. However, competitive adsorption between proteins and PLs can disrupt interfacial structure. In addition, for commercial production, emulsions are often exposed to heat treatment during or after manufacture, for instance due to food safety requirements. Yet, the combined effects of PL structure and heat treatment on interfacial organisation and emulsion stability remain poorly understood.
Here we show that PL saturation and processing temperature jointly determine interfacial organisation, protein-PL interactions and emulsion stability. Using β-LG-PL emulsions, we combined ζ-potential measurements, small-angle X-ray scattering (SAXS), micro-differential scanning calorimetry (μDSC), X-ray diffraction and confocal laser scanning microscopy (CLSM) to link interfacial composition with functional stability.
Below the β-LG denaturation temperature (≤75 °C), saturated PLs promoted partial unfolding of β-LG at the interface without displacement, producing mixed protein-PL networks with enhanced viscoelasticity and stability. Unsaturated PLs displaced β-LG, yielding less elastic interfaces and promoting protein aggregation in the bulk. At ≥75 °C, increased hydrophobicity intensified protein-protein interactions irrespective of PL type.
Our findings reveal that saturated PLs shift the β-LG denaturation temperature upward by restricting molecular mobility, without preventing quaternary-level protein-protein interactions. Thermal denaturation, regardless of PL type, promoted interfacial multilayer formation at 90 °C. These results provide a mechanistic framework for tailoring emulsion stability via lipid saturation and processing temperature.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Reference Method
KW - Colloid
KW - Nanoparticle
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648956
DO - https://doi.org/10.1016/j.jcis.2025.139530
SN - 0021-9797
VL - 705
SP - 1
EP - 25
PB - Elsevier Inc.
AN - OPUS4-64895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thünemann, Andreas
A1 - Gruber, Alexandra
A1 - Klinger, Daniel
T1 - Amphiphilic Nanogels: Fuzzy Spheres with a Pseudo-Periodic Internal Structure
N2 - Amphiphilic polymer nanogels (NGs) are promising drug delivery vehicles that extend the application of conventional hydrophilic NGs to hydrophobic cargoes. By randomly introducing hydrophobic groups into a hydrophilic polymer network, loading and release profiles as well as surface characteristics of these colloids can be tuned. However, very little is known about the underlying internal structure of such complex colloidal architectures. Of special interest is the question how the amphiphilic network composition influences the internal morphology and the “fuzzy” surface structure. To shine light into the influence of varying network amphiphilicity on these structural features, we investigated a small library of water-swollen amphiphilic NGs using small-angle X-ray scattering (SAXS). It was found that overall hydrophilic NGs, consisting of pure poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA), display a disordered internal structure as indicated by the absence of a SAXS peak. In contrast, a SAXS peak is present for amphiphilic NGs with various amounts of incorporated hydrophobic groups such as cholesteryl (CHOLA) or dodecyl (DODA). The internal composition of the NGs is considered structurally homologous to microgels. Application of the Teubner–Strey model reveals that hydrophilic PHPMA NGs have a disordered internal structure (positive amphiphilicity factor) while CHOLA and DODA samples have an ordered internal structure (negative amphiphilicity factor). From the SAXS data it can be derived that the internal structure of the amphiphilic NGs consists of regularly alternating hydrophilic and hydrophobic domains with repeat distances of 3.45–5.83 nm.
KW - Polymer
KW - Nanoparticle
KW - SAXS
PY - 2020
DO - https://doi.org/10.1021/acs.langmuir.0c01812
VL - 36
IS - 37
SP - 10979
EP - 10988
PB - American Chemical Society
AN - OPUS4-51302
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tiebe, Carlo
A1 - Zunkel, Astrid
A1 - Klein, Ulrich
A1 - Schlischka, Jörg
A1 - Klinger, Christian
T1 - Materialuntersuchungen zur Schadensanalyse an einem explodierten Umlaufkühler
N2 - Ein Durchlaufkühler ist im Betrieb explodiert. Die zerborstenen Gehäuseteile aus Kunststoff führten zu einem Austreten der Kühlflüssigkeit am Betriebsort sowie zu einem Personenschaden mit Knalltrauma. Bei Funktionsprüfungen am beschädigten Gerät traten unerwartet, aber reproduzierbar Knalleffekte auf der Kupfer-Kühlschlange auf. Ein möglicher Mechanismus konnte im Labor durch Synthese von Kupferazid auf Kupferproben und Auslösung vergleichbarer Knalleffekte nachgestellt werden. Damit ist die Plausibilität des beschriebenen Schadensereignisses mit diesem oder einem ähnlich reagierenden Stoff belegt. Ein eindeutiger Nachweis darüber, dass beim aufgetretenen Schadensfall dieselbe chemische Reaktion stattgefunden hat ist nicht möglich, da die Belag-Überreste aus dem explodierten Kühlgerät für eine Analyse nicht mehr in ausreichender Menge verfügbar waren.
T2 - Erfahrungsaustausch für Sachverständige in der Anlagenüberwachung der Industrie (ESA 2021)
CY - Online meeting
DA - 20.04.2021
KW - Umlaufkühler
KW - Schadensanalyse
KW - Materialuntersuchungen
KW - Gutachten
KW - Kupferazid
PY - 2021
AN - OPUS4-52484
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tiebe, Carlo
T1 - Materialuntersuchungen zur Schadensanalyse an einem explodierten Umlaufkühler
N2 - Ein Umlaufkühler ist im Betrieb explodiert. Splitter des zerborstenen Gehäuses aus Kunststoff wurden mit dem Kühlwasser in die Umgebung geschleudert, am Betriebsort entstand Personenschaden. Bei Funktionsprüfungen am beschädigten Gerät traten unerwartet - aber reproduzierbar - Knalleffekte bei Berührung der Außenoberfläche der Kupfer-Kühlschlange auf. Ein möglicher Mechanismus konnte im Labor durch Synthese von Kupferazid auf Kupferproben und Auslösung vergleichbarer Knalleffekte nachgestellt werden. Damit ist die Plausibilität des beschriebenen Schadensereignisses mit diesem oder einem ähnlich reagierenden Stoff belegt. Ein eindeutiger Nachweis darüber, dass bei dem aufgetretenen Schadensfall dieselbe chemische Reaktion stattgefunden hat, war nicht möglich, da die Belag-Überreste aus dem explodierten Kühlgerät für eine Analyse nicht mehr in ausreichender Menge verfügbar gewesen sind.
T2 - BG RCI Präventionstagung, Teil 11 - Inkompatible Systeme – Wenn Chemikalien und Werkstoffe heftig reagieren
CY - Online meeting
DA - 19.01.2022
KW - Explosion
KW - Gutachten
KW - Kupferazid
KW - Materialuntersuchung
KW - Schadensanalyse
KW - Umlaufkühler
PY - 2022
AN - OPUS4-56686
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tiebe, Carlo
A1 - Zunkel, Astrid
A1 - Klein, Ulrich
A1 - Schlischka, Jörg
A1 - Klinger, Christian
T1 - Materialuntersuchungen an einem explodierten Umlaufkühler
N2 - Ein Umlaufkühler ist im Betrieb explodiert. Splitter des zerborstenen Gehäuses aus Kunststoff wurden mit dem Kühlwasser in die Umgebung geschleudert, am Betriebsort entstand Personenschaden. Bei Funktionsprüfungen am beschädigten Gerät traten unerwartet - aber reproduzierbar - Knalleffekte bei Berührung der Außenoberfläche der Kupfer-Kühlschlange auf. Ein möglicher Mechanismus konnte im Labor durch Synthese von Kupferazid auf Kupferproben und Auslösung vergleichbarer Knalleffekte nachgestellt werden. Damit ist die Plausibilität des beschriebenen Schadensereignisses mit diesem oder einem ähnlich reagierenden Stoff belegt. Ein eindeutiger Nachweis darüber, dass bei dem aufgetretenen Schadensfall dieselbe chemische Reaktion stattgefunden hat, war nicht möglich, da die Belag-Überreste aus dem explodierten Kühlgerät für eine Analyse nicht mehr in ausreichender Menge verfügbar gewesen sind.
KW - Kupferazid
KW - Umlaufkühler
KW - Explosion
KW - Gutachten
KW - Schadensanalyse
KW - Materialuntersuchung
PY - 2022
SN - 2191-0073
VL - 12
IS - 7/8
SP - 15
EP - 21
PB - VDI Fachmedien
CY - Düsseldorf
AN - OPUS4-55570
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stock, V.
A1 - Fahrenson, C.
A1 - Thünemann, Andreas
A1 - Donmez, M. H.
A1 - Voss, L.
A1 - Bohmert, L.
A1 - Braeuning, A.
A1 - Lampen, A.
A1 - Sieg, H.
T1 - Impact of artificial digestion on the sizes and shapes of microplastic particles
N2 - Current analyses show a widespread occurrence of microplastic particles in food products and raise the question of potential risks to human health. Plastic particles are widely considered to be inert due to their low chemical reactivity and therefore supposed to pose, if at all only minor hazards. However, variable physicochemical conditions during the passage of the gastrointestinal tract gain strong importance, as they may affect particle characteristics. This study aims to analyze the impact of the gastrointestinal passage on the physicochemical particle characteristics of the five most produced and thus environmentally relevant plastic materials polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate and polystyrene. Scanning electron microscopy (SEM) and subsequent image analysis were employed to characterize microplastic particles. Our results demonstrate a high resistance of all plastic particles to the artificial digestive juices. The present results underline that the main stages of the human gastrointestinal tract do not decompose the particles. This allows a direct correlation between the physicochemical particle characteristics before and after digestion. Special attention must be paid to the adsorption of organic compounds like proteins, mucins and lipids on plastic particles since it could lead to misinterpretations of particle sizes and shapes.
KW - Artificial digestion
KW - Gastrointestinal barrier
KW - Microplastic
KW - Oral uptake
KW - Particle size
PY - 2020
DO - https://doi.org/10.1016/j.fct.2019.111010
VL - 135
SP - 111010
PB - Elsevier Ltd.
AN - OPUS4-49999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baglo, K.
A1 - Sauermoser, M.
A1 - Lid, M.
A1 - Paschke, T.
A1 - Bin Afif, A.
A1 - Lunzer, M.
A1 - Bock, Robert
A1 - Steinert, M.
A1 - Flaten, A.
A1 - Torgersen, J.
T1 - Overcoming the transport limitations of photopolymer-derived architected carbon
N2 - Photopolymer derived carbon grows in popularity, yet the range in available feature sizes is limited. Here we focus on expanding the field to low surface to volume ratio (SVR) structures. We describe a high temperature acrylic photopolymerizable precursor with FTIR and DSC and develop a thermal inert-gas treatment for producing architected carbon in the mm scale with SVR of 1.38 x10-3 μm-1. Based on TGA and MS, we distinguish two thermal regimes with activation energies of ~79 and 169 kJ mol-1, which we reason with mechanisms during the polymer’s morphologic conversion between 300 - 500 °C. The temperature range of the major dimensional shrinkage (300-440 °C, 50%) does not match the range of the largest alteration in elemental composition (440-600 °C, O/C 0.25-0.087%). The insights lead to an optimized thermal treatment with an initial ramp (2 °C min-1 to 350 °C), isothermal hold (14h), post hold ramp (0.5 °C min-1 to 440 °C) and final ramp (10 °C min-1 to 1000 °C). The resulting carbon structures are dimensionally stable, non-porous at the μm scale, and comprise an unprecedented variation in feature sizes (from mm to μm scale). The findings shall advance architected carbon to industrially relevant scales.
KW - Carbon
KW - Photopolymer
KW - Transport limitations
KW - Porous materials
KW - Additive manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575038
DO - https://doi.org/10.1002/admt.202300092
SN - 2365-709X
SP - 2300092
PB - Wiley-VCH GmbH
AN - OPUS4-57503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Ballach, F.
A1 - Bartscher, M.
A1 - Bellon, Carsten
A1 - Borges de Oliveira, F.
A1 - Braun, M.
A1 - Dennerlein, F.
A1 - Flessner, M.
A1 - Fuchs, P.
A1 - Günnewig, O.
A1 - Hausotte, T.
A1 - Hess, J.
A1 - Kasperl, S.
A1 - Kirschbaum, K.
A1 - Li, K.
A1 - Maass, N.
A1 - Mayer, T.
A1 - Orth, Anthony
A1 - Reuter, T.
A1 - Suppes, A.
A1 - von Schmid, M.
A1 - Weiß, D.
T1 - Realistische Simulation realer Röntgencomputertomografie-Systeme mit basisqualifizierter Simulationssoftware – CTSimU2
BT - Abschlussbericht
N2 - Das Förderprojekt CTSimU2 baute auf den Ergebnissen des Projektes CTSimU auf. Dieses Vorprojekt erarbeitete ein (Basis-)Qualifizierungsframework für Simulationssoftwares zur Anwendung bei der Röntgen-CT für dimensionelle Messungen. Dabei stand die ausreichende physikalische Korrektheit der Durchstrahlungssimulation im Vordergrund. Für die realitätsnahe Simulation einer CT-Anlage in einer Simulationssoftware (Digitales Modell) ist jedoch nicht nur die Korrektheit der Simulationssoftware selbst, sondern auch die Güte der Parametrisierung des realen CT-Systems in der Simulationssoftware entscheidend – dies stellte den Ausgangspunkt dar. Die Parametrisierung eines CT-Systems in einer Simulationssoftware lässt sich in vier Schritte unterteilen: nach der Datenaufnahme am realen CT-System folgt die Auswertung der aufgenommenen Daten für die Generierung allgemeiner Parameterangaben. Als letztes folgte die Übertragung der Parameter in die spezifischen Simulationssoftwares und die Validierung der resultierenden Simulationsparameter. Die Methodik der Datenaufnahme am CT und die Auswertung der Daten wurde in einem Werkzeugkasten allgemein beschrieben. Der dritte Schritt, die Umsetzung der Parameter, war softwarespezifisch und wurde beispielhaft mit den vorhandenen Simulationssoftwares durchgeführt. Die Validierung der Parameter war standardisierbar und konnte durch den entwickelten Test geleistet werden, auf dessen Basis die ausreichend korrekte Simulation einer realen Anlage beurteilt werden konnte. Endresultat des Projektes war ein Richtlinienentwurf (z. B. VDI/VDE 2630) zu diesem Test, der einen informativen Annex zum Stand der Technik bezüglich der Möglichkeiten zur Parameterbestimmung enthält. Mit einer Simulationssoftware, die die Basisqualifizierung aus CTSimU bestanden hat und einen Parameterdatensatz für ein reales CT-System enthält, der den Test aus CTSimU2 bestanden hat, können realistische Simulationen dieses CT-Systems möglich sein.
KW - Computertomografie
KW - Simulation
KW - Dimensionelles Messen
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641719
DO - https://doi.org/10.34657/21602
N1 - Dieses Projekt wurde durch die Förderrichtlinie WIPANO gefördert und durch das Bundesministerium für Wirtschaft und Klimaschutz (2022 -2025) finanziert. Der Projektträger Jülich verwaltet die Projekte der Förderrichtlinie WIPANO.
SP - 1
EP - 22
PB - TIB Technische Informationsbibliothek
CY - Hannover
AN - OPUS4-64171
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy
N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs.
T2 - Adlershofer Forschungsforum 2022
CY - Berlin, Germany
DA - 11.11.2022
KW - Lithium Ion Batteries
KW - GD-OES
KW - FIB
KW - SEM
KW - EDX
PY - 2022
AN - OPUS4-56246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Unveiling Effects of Biodiesel and Diesel on Environmental Stress Cracking of PE-HD
N2 - The behavior of high‐density polyethylene with respect to resistance against environmental stress cracking (ESC) is usually regarded as an inherent material property being specific for respective types of PE‐HD and tested using standardized methods, conditions, and also standard testing liquids (usually aqueous surfactant solutions). On the other hand, for practical applications the ESC behavior of those polymeric materials, commonly used for pipes or containers, in contact with other liquids (e.g., fuels) is often of relevant interest, but for a reasonable assessment, where consistent benchmark data for a direct comparison are often missing, it is essential to determine the actually prevailing failure mode and classify it related to crack propagation or other mechanisms. Using the well‐established Full Notch Creep Test, which favorably allows for a detailed microscopic fracture surface analysis after failure, the behavior of two typical PE‐HD types for container applications is investigated in biodiesel and diesel and compared to a standard surfactant solution. This enables a clear identification of characteristic features of the interaction of biodiesel and diesel as sorptive fuels in contact with the polymer, revealing the complex interplay of sorption and plasticization as well as ESC inducing effects on PE‐HD, which could be clearly shown for both fuels.
KW - Biodiesel
KW - Confocal laser scanning microscopy (LSM)
KW - Diesel
KW - Full notch creep test (FNCT)
KW - Plasticization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650525
DO - https://doi.org/10.1002/pen.70239
SN - 0032-3888
SP - 1
EP - 16
PB - Wiley
CY - Hoboken (NJ)
AN - OPUS4-65052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by glow-discharge optical emission spectroscopy
N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs.[1] Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs.
T2 - European Winter Conference on Plasma Spectrochemistry (EWCPS 2023)
CY - Ljubljana, Slovenia
DA - 29.01.2023
KW - Lithium-ion batteries
KW - Aging mechanisms
KW - Depth-profiling
PY - 2023
AN - OPUS4-56992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Investigation of degradation of the aluminum current collector in lithium-ion batteries by GD-OES
N2 - Lithium-ion batteries (LIBs) are one technology to overcome the challenges of climate and energy crisis. They are widely used in electric vehicles, consumer electronics, or as storage for renewable energy sources. However, despite innovations in batteries' components like cathode and anode materials, separators, and electrolytes, the aging mechanism related to metallic aluminum current collector degradation causes a significant drop in their performance and prevents the durable use of LIBs. Glow-discharge optical emission spectroscopy (GD-OES) is a powerful method for depth-profiling of batteries' electrode materials. This work investigates aging-induced aluminum deposition on commercial lithium cobalt oxide (LCO) batteries' cathodes. The results illustrate the depth-resolved elemental distribution from the cathode surface to the current collector. An accumulation of aluminum is found on the cathode surface by GD-OES, consistent with results from energy-dispersive X-ray spectroscopy (EDX) combined with focused ion beam (FIB) cutting. In comparison to FIB-EDX, GD-OES allows a fast and manageable depth-profiling. Results from different positions on an aged cathode indicate an inhomogeneous aluminum film growth on the surface. The conclusions from these experiments can lead to a better understanding of the degradation of the aluminum current collector, thus leading to higher lifetimes of LIBs.
T2 - Empa Group Meeting
CY - Dübendorf, Switzerland
DA - 22.11.2022
KW - Lithium Ion Batteries
KW - GD-OES
KW - FIB
KW - SEM
KW - EDX
PY - 2022
AN - OPUS4-56584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunkel, Benny
A1 - Seeburg, Dominik
A1 - Kabelitz, Anke
A1 - Witte, Steffen
A1 - Gutmann, Torsten
A1 - Breitzke, Hergen
A1 - Buntkowsky, Gerd
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, Sebastian
T1 - Highly productive V/Zn-SiO2 catalysts for the selective oxidation of methane
N2 - The production of formaldehyde on industrial scale requires huge amounts of energy due to the involvement of reforming processes in combination with the demand in the megaton scale. Hence, a direct route for the transformation of (bio)methane to formaldehyde would decrease costs and puts less pressure on the environment. Herein, we report on the use of zinc modified silicas as possible support materials for vanadium catalysts and the resulting consequences for the performance in the selective oxidation of methane to formaldehyde. After optimization of the Zn content and reaction conditions, a remarkably high space-time yield of 12.4 kgCH2O⋅kgcat − 1 ⋅h− 1 was achieved. As a result of the extensive characterization by means of UV–vis, Raman, XANES and NMR spectroscopy it was found that vanadium is in the vicinity of highly dispersed zinc atoms which promote the formation of active vanadium species as supposed by theoretical calculations. This work presents a further step of catalyst development towards direct industrial methane conversion which may help to overcome current limitations in the future.
KW - Catalysis
KW - XANES
KW - Selective oxidation
PY - 2024
DO - https://doi.org/10.1016/j.cattod.2024.114643
SN - 0920-5861
VL - 432
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pessanha, Sofia
A1 - Fortes, António
A1 - Lopes, Marta B.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ortega-Feliu, Inés
A1 - Respaldiza, Miguel A.
A1 - Gomez Tubio, Blanca
A1 - Makarova, Anna
A1 - Smirnov, Dmitry
A1 - Kumar, Sourabh
A1 - Mata, António
A1 - Silveira, João
T1 - Multi-technique computational assessment of fluoride uptake in enamel using PIGE, NEXAFS, and Raman spectroscopy
N2 - This study explores F incorporation in enamel via PIGE, NEXAFS, and Raman spectroscopy, integrating experimental/simulated spectra. Machine Learning boosts data interpretation, offering key insights into F delivery for clinical application.
KW - Simulations
KW - Enamel
KW - Fuorine
KW - NEXAFS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631138
DO - https://doi.org/10.1039/D5TB00213C
SN - 2050-750X
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
T1 - On the tribological behaviour of polymer composites in vacuum
N2 - This lecture deals with the sliding behaviour of polymer composites in vacuum environment. At first, the effect of the polymer matrix and solid lubricants such as graphite and MoS2 are presented. The second part focusses on the influence of the residual pressure with experimental results obtained in high and ultrahigh vacuum.
T2 - Invited lecture, TRIBOS+ program at Lulea University of Technology
CY - Lulea, Sweden
DA - 29.06.2021
KW - Polymers
KW - Vacuum
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-53710
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Channammagari, Harichandana
A1 - Sahr, Rabea
A1 - Trappe, Volker
T1 - Experimentelle, Analytisch-Numerische Untersuchung des thermischen Ausdehnungsverhaltens von Faser-Kunststoff-Verbunden
N2 - Im Rahmen des Forschungsvorhabens PROVING wurde eine Methode zur rechnerischen Bestimmung thermomechanischer Eigenspannungen in CFK entwickelt. Ziel ist die Berücksichtigung des thermischen Ausdehnungsverhaltens bei der Bestimmung des dreidimensionalen in-situ-Spannungszustands der Matrix für den strukturellen Nachweis. Die Eigenspannungen werden über mikromechanische Modellierung und FEM berechnet; die zugrunde liegenden Ausdehnungsfunktionen wurden experimentell validiert.
N2 - As part of the PROVING research project, a method for calculating thermomechanical residual stresses in CFRP was developed. The aim is to take thermal expansion behavior into account when determining the three-dimensional in-situ stress state of the matrix for structural verification. The residual stresses are calculated using micromechanical modeling and FEM; the underlying expansion functions have been experimentally validated.
T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025
CY - Dresden, Germany
DA - 27.11.2025
KW - Thermische Eigenspannungen
KW - Mikromechanik
KW - Faser-Kunststoff-Verbunde
KW - FEM
PY - 2025
SN - 978-3-88355-454-9
VL - 2025
SP - 154
EP - 159
PB - DGM
CY - Sankt Augustin
AN - OPUS4-65112
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sahr, Rabea
T1 - Experimentelle, Analytisch-Numerische Untersuchung des Thermischen Ausdehnungsverhaltens von Faser-Kunststoff-Verbunden
N2 - Im Rahmen des Forschungsvorhabens PROVING wurde eine Methode zur rechnerischen Bestimmung thermomechanischer Eigenspannungen in CFK entwickelt. Ziel ist die Berücksichtigung des thermischen Ausdehnungsverhaltens bei der Bestimmung des dreidimensionalen in-situ-Spannungszustands der Matrix für den strukturellen Nachweis. Die Eigenspannungen werden über mikromechanische Modellierung und FEM berechnet; die zugrunde liegenden Ausdehnungsfunktionen wurden experimentell validiert.
T2 - 43. Vortrags- und Diskussionstagung Werkstoffprüfung 2025
CY - Dresden, Germany
DA - 27.11.2025
KW - Thermische Eigenspannungen
KW - Mikromechanik
KW - Faser-Kunststoff-Verbunde
KW - FEM
PY - 2025
AN - OPUS4-65118
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal friction and energy dissipation during fracture in silicate glasses
N2 - To obtain a deeper insight into the nature of energy dissipation during fracture, the internal friction of 13 borosilicate, aluminosilicate, soda-lime, and lead-containing glasses, for which inert crack growth data are known, was measured using dynamic mechanical thermal analysis. For asymmetrically bent glass beams, the loss tangent, tan δ, was determined between 0.2 and 50 Hz at temperatures between 273 K and the glass transition temperature, Tg. It was found that the area under the tan δ vs T·Tg−1 curve correlates with the crack growth exponent, n, in the empirical v = v0·KIn relation between crack growth velocity, v, and stress intensity, KI, which indicates that n correlates with the degree of energy dissipation of sub-Tg relaxation phenomena.
KW - Glass
KW - Internal friction
KW - Crack growth
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651371
DO - https://doi.org/10.1063/5.0255432
SN - 0021-9606
VL - 162
IS - 19
SP - 1
EP - 9
PB - AIP Publishing
AN - OPUS4-65137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pan, Z.
A1 - Waurischk, Tina
A1 - Duval, A.
A1 - Müller, Ralf
A1 - Deubener, J.
A1 - Krishnan, N. M. A.
A1 - Wondraczek, K.
A1 - Wondraczek, L.
T1 - Precise Real‐Time Measurement of Liquid Viscosity Using Digital Video Data
N2 - Quantitative knowledge of liquid viscosity is of fundamental importance in many areas of materials synthesis and processing. However, the determination of viscosity often relies on specialized experimental equipment, offline experimentation, or invasive procedures, in particular when required in extreme conditions such as at high temperature, high pressure, and in confined or corrosive environments. Here, this study proposes and validates a fast and simple method that mimics the intuitive perception of liquid flow within a quantitative framework. For this, this study employs digital video observation to derive quantitative values of the shear viscosity of liquids, with high precision and rapid acquisition rates. The technique involves capturing liquid dynamics after minor mechanical stimulation. Processed imaging data are indexed by similarity and referenced to a digital database generated with a finite element model, from which values of viscosity are obtained in line. The approach is tested on water at room temperature and on a high‐temperature glass melt. Covering a viscosity range of four orders of magnitude, both yield convincing agreement with tabulated reference data at low computational cost.
KW - Glass
KW - Liquid Viscosity
KW - Digital Video Data
KW - Finite Element Method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651363
DO - https://doi.org/10.1002/aisy.202500297
SN - 2640-4567
VL - 7
IS - 12
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-65136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nikoonasab, Ali
A1 - Licht, M.
A1 - Weiler, L.
A1 - Achenbach, R.
A1 - Raupach, M.
A1 - Gluth, Gregor
T1 - Pore Solution composition of GGBFS-containing cement pastes
N2 - Ground Granulated Blast-Furnace Slag (GGBFS), a by-product of the iron-making process, has gained significant attention as a supplementary cementitious material and has become increasingly popular in recent years due to its remarkable properties. GGBFS can significantly reduce the environmental impact of cement production when it comes to building concrete structures. GGBFS can either be blended with ordinary Portland cement (OPC) (up to a 90% replacement), or it can be used in the production of alkali-activated materials (AAMs). However, a comprehensive understanding of the pore solution composition is necessary for understanding various aspects of cementitious materials and their durability, including corrosion behavior, passivation of steel, and resistance to deteriorative processes. In the present work, the pore solutions of seven different GGBFS-containing cements (alkali-activated slag, alkali-activated slag/fly ash blends, a hybrid alkaline cement, CEM III/C, and CEM III/B) were extracted and analysed by inductively coupled plasma-optical emission spectroscopy, ion chromatography, pH, redox potential, and conductivity measurements. For comparison, a Portland cement pore solution was analysed similarly. The Concentrations of reduced sulfur were noteworthy in all GGBFS-containing cements, particularly in alkali-activated cements, where concentrations were notably higher compared to standard cements. The redox potentials of the pore solutions were primarily dictated by the concentrations of reduced sulfur, although other factors may contribute. Additionally, sulfur species in the pore solutions had an impact on pH, electrical conductivity, and other properties pertinent to the corrosion of reinforcements.
T2 - RILEM Spring Convention 2024 & Conference on Advanced Construction Materials and Processes for a Carbon Neutral Society
CY - Milan, Italy
DA - 10.04.2024
KW - GGBFS
KW - AAM
KW - Sulfide
KW - Pore solution composition
KW - Redox potential
PY - 2024
AN - OPUS4-59960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Exploring new materials for Green Intelligent Building how can our BAMline help
N2 - With increasing demand and environmental concerns, researchers are exploring new materials that can perform as well or better than traditional materials while reducing environmental impact. Synchrotron X-ray based methods enable unique tools to probe materials properties via e.g. X-ray spectroscopy and diffraction methods. The BAM plays a central role in this highly collaborative research. The BAMline, a real-life sample materials research beamline, at the Berlin Synchrotron BESSY-II, provides unique insights into materials’ electronic and chemical structure at different time and length scales1. This enables real-time optimization of material properties and performance for various applications, such as energy storage and conversion, catalysis, and deterioration resistance.
T2 - DAfStb-Kolloquium
CY - Berlin, Germany
DA - 16.10.2024
KW - XAS
KW - Time-resolved studies
KW - Binding materials
KW - Cements
PY - 2024
AN - OPUS4-61616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray absorption spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - European Conference on X-ray Spectrometry 2022
CY - Bruges, Belgium
DA - 27.06.2022
KW - XAS
KW - Mechanochemictry
KW - Time resolved
KW - In situ
PY - 2022
AN - OPUS4-56258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Soni, Akshar
T1 - Simulation of functional ageing towards failure prediction of dental restorations - Investigating the Crown-Cement-Tooth Complex (CCTC)
N2 - Dental crown restorations are the most common type of indirect restoration in Germany, with over 5 million crowns placed annually. Clinical complications such as debonding and crown fractures cannot yet be adequately correlated with cement ageing processes. The SimuCrown project systematically investigates the ageing mechanisms of the crown–cement–tooth complex (CCTC) while also validating the in vitro methodology itself. This interdisciplinary cooperation combines experimental ageing simulation (Charité), computer-aided finite element method based simulation (TU Berlin), and high-resolution structural analysis using synchrotron-based X-ray refraction radiography (SXRR) on BAMline at BESSY II (BAM).
T2 - 17th BESSY@HZB User Meeting
CY - Berlin, Germany
DA - 03.12.2025
KW - X-ray refraction
KW - Synchrotron radiation
KW - Dental Materials
KW - Crown-cement-tooth complex (CCTC)
KW - Crack evolution
PY - 2025
AN - OPUS4-65166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scharf-Wildenhain, R.
T1 - Influence of build up height on residual stresses in additive repair and modification using DED Arc
N2 - Directed Energy Deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between AM component and semi-finished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead component failure. Therefore, understanding and controlling residual stresses, especially when combining different base and filler materials, is critical to improving the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and filler material combination. Using a robot-assisted DEDsystem and a controlled short arc, systematic step cancellation tests were carried out at a selected working temperature (200 C°) and heat input (600 kJ/m). In a 5-stage termination experiment, straight walls were produced using a one bead per layer strategy and selected increasing component heights between 15 mm and 300 mm. The influence of the build height on the longitudinal residual stress in the process direction was analyzed and discussed. All experiments showed a comparable stress distribution in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the buliding height. However, the height showed a significant influence on the of residual stress distribution of the deposited AM-component. High positive stress gradients with a maximum range between 300 MPa to 400 MPa were always found in the last approx. 18 component layers (upper 40 mm), which can be explained by the shrinkage of the nonheat- treated top layer. Underlying layers, where present, showed a homogeneous residual stress distribution characterized by low compressive stresses. This can be explained by the process related tempering during the deposition of the upper layers. A constant boundary layer number was determined for all specimens. Once this number was exceeded, the distribution of residual stresses no longer changed, but merely shifted with the increasing height of the component in the direction of build-up. These correlations contribute to the understanding of residual stress development with increasing structure height. This study is part of a running research project on the properties of hybrid additive components and processes. It aims the stress optimized hybrid additive manufacturing of high-strength components and the necessary recommendations for application.
T2 - 78th IIW Annual Assembly and International Conference on Welding and Joining
CY - Genoa, Italy
DA - 22.06.2025
KW - DED-Arc
KW - Additive manufacturing
KW - Residual stress
PY - 2025
AN - OPUS4-65192
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Channammagari, Harichandana
T1 - From Micromechanics to Macro Validation: A New Approach for Aerospace Structures
N2 - Given the high experimental effort required to verify fiber‑reinforced polymer composites (FRP) in aviation, the PROVING project (Production, Optimization, and Virtual Verification for Generative Manufacturing Processes) aims to establish a streamlined and robust verification methodology based on analytical and numerical approaches. As a foundation for this virtual verification process, BAM contributed extensive material testing for parameter identification, feeding directly into the material models and probabilistic methods.
Beyond the experiments, an analytical‑numerical model was developed to more accurately determine the in‑situ stress state within the composite matrix. Since damage initiation in FRP is largely driven by inter-fiber failure, the three‑dimensional matrix stress state is essential for structural verification. In addition to external loading, thermomechanical residual stresses arising from the mismatched thermal expansion of fibers and matrix contribute to the stress state.
Within PROVING, a calculation method was developed that incorporates the thermomechanical behavior of carbon‑fiber‑reinforced polymers (CFRP) into the verification process with minimal experimental effort. The method determines matrix thermal residual stresses using micromechanical modeling combined with finite element analysis.
T2 - 29. Nationales SAMPE Symposium
CY - Aachen, Germany
DA - 02.04.2025
KW - Virtual Verification
KW - Micromechanics
KW - FEA
PY - 2025
AN - OPUS4-65187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Wear resistance of modified Ni based claddings in relation to the resulting machinability via ultrasonic-assisted milling
N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses).
T2 - Wear of Materials 2025
CY - Sitges, Spain
DA - 13.04.2025
KW - Abrasive wear
KW - Adhesive wear
KW - Colmonoy C56
KW - PTA welding
KW - Service life and efficiency
KW - Substitution of critical raw materials
KW - Surface integrity
KW - Ultrasonic-assisted milling process
PY - 2025
AN - OPUS4-65189
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Tavernaro, Isabella
A1 - Scholtz, Lena
A1 - Genger, C.
A1 - Welker, P.
A1 - Schreiber, Frank
A1 - Meyer, Klas
A1 - Resch-Genger, Ute
T1 - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies
N2 - Ratiometric green–red fluorescent nanosensors for fluorometrically monitoring pH in the acidic range were designed from 80 nm-sized polystyrene (PS) and silica (SiO2) nanoparticles (NPs), red emissive reference dyes, and a green emissive naphthalimide pH probe, analytically and spectroscopically characterized, and compared regarding their sensing performance in aqueous dispersion and in cellular uptake studies. Preparation of these optical probes, which are excitable by 405 nm laser or LED light sources, involved the encapsulation of the pH-inert red-fuorescent dye Nile Red (NR) in the core of self-made carboxylated PSNPs by a simple swelling procedure and the fabrication of rhodamine B (RhB)-stained SiO2-NPs from a silane derivative of pH-insensitive RhB. Subsequently, the custom-made naphthalimide pH probe, that utilizes a protonation-controlled photoinduced electron transfer process, was covalently attached to the carboxylic acid groups at the surface of both types of NPs. Fluorescence microscopy studies with the molecular and nanoscale optical probes and A549 lung cancer cells confirmed the cellular uptake of all probes and their penetration into acidic cell compartments, i.e., the lysosomes, indicated by the switching ON of the green naphthalimide fluorescence. This underlines their suitability for intracellular pH sensing, with the SiO2-based nanosensor revealing the best performance regarding uptake speed and stability.
KW - Sensors
KW - Silica and polystyrene nanoparticles
KW - pH probe
KW - Fluorescence spectroscopy
KW - Cell studies
KW - Dye
KW - Particle synthesis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569198
DO - https://doi.org/10.1038/s41598-023-28203-0
SN - 2045-2322
VL - 13
IS - 1
SP - 1321
EP - 1336
PB - Nature
CY - London
AN - OPUS4-56919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keshmiri, Hamid
A1 - Armin, F.
A1 - Elsayad, K.
A1 - Schreiber, Frank
A1 - Moreno, M.
T1 - Leaky and waveguide modes in biperiodic holograms
N2 - This study details a theoretical analysis of leaky and waveguide modes in biperiodic all-dielectric holograms. By tuning diffraction orders and subsequently confining local density of optical states at two distinct resonance wavelengths, we present a new class of highly sensitive refractive index biosensing platforms that are capable of resolving 35.5 to 41.3 nm/RIU of spectral shift for two separate biological analytes.
KW - Antimicrobial resistance
KW - Bacteria
KW - Photonics
KW - Diffractive gratings
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527632
DO - https://doi.org/10.1038/s41598-021-89971-1
SN - 2045-2322 (online)
VL - 11
IS - 1
SP - 10991
PB - Springer Nature
AN - OPUS4-52763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Keshmiri, Hamid
T1 - Bidiffractive leaky-mode biosensor
N2 - This study details a thorough analysis of leaky and waveguide modes in biperiodic diffractive nanostructures. By tuning diffraction orders and subsequently confining local density of optical states at two distinct resonance wavelengths, we present a highly sensitive refractive index biosensing platform that can resolve 35.5 to 41.3 nm/RIU of spectral shift for two separate biological analytes.
T2 - EMBL Symposium: Seeing is Believing - Imaging the Molecular Processes of Life
CY - Heidelberg, Germany
DA - 04.10.2023
KW - Optics
PY - 2023
AN - OPUS4-59247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Viguier, B.
T1 - Creep of single-crystals of nickel-base gamma-alloy at high temperatures
N2 - Porosity in single-crystal nickel-base superalloys is removed by hot isostatic pressing (HIP) at temperatures above gamma’-solvus where the material is very soft and ductile. For example, single-crystal nickel-base superalloy CMSX-4 is HIPed at temperature 1288 °C, which is slightly higher than the gamma’-solvus temperature of this alloy equal to about 1280 °C. It is assumed that pore shrinking during HIP is mostly due to dislocation creep. Such a modelling of HIP of CMSX-4 was started in our group on the base of results of creep tests of [001] single-crystals at 1288 °C [1]. However, it was found later [2] that the alloy CMSX-4 shows very strong creep anisotropy at 1288 °C. Therefore, for calibration of the creep law, creep tests of different orientations under different stress levels are required at the HIP temperature. This was the main task of present work. Single-crystals of CMSX-4 of axial orientations [001], [011], [123] and [111] were cast by VIAM Moscow and tested by BAM Berlin under creep conditions at 1288 °C and stress levels between 4 MPa and 16 MPa. At all stress levels, the creep rate increases by an order of magnitude when changing the orientation from [001] to [111] with [011] and [123] orientations in between. Such a character of creep anisotropy corresponds to the orientation dependence of the Schmid factor for octahedral glide.
The crystal viscoplasticity model developed in [1] was improved to better represent the time induced softening observed during creep. The creep tests for different stresses and orientations as well as pore closure were simulated. The results of pore closure simulation are compared with measurements of porosity decrease during Hiping.
T2 - 15th International Conference on Creep and Fracture of Engineering Materials and Structures
CY - Online meeting
DA - 14.06.2021
KW - Nickel-base superalloys
KW - Creep
KW - Single-Crystal
PY - 2021
AN - OPUS4-53935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Fedelich, Bernard
ED - Cailletaud, G.
ED - Cormier, J.
ED - Eggeler, G.
ED - Maurel, V.
ED - Nazé, L.
T1 - Crystal orientation and elastic properties
N2 - The elastic constants are the most basic mechanical properties of a material and are needed for any structural analysis of a component. For example, they have a major influence on the eigenfrequencies of vibrating parts. Single crystals of Ni-base superalloys are strongly anisotropic, which means that the observed properties are orientation dependent. Tensor algebra is then required to mathematically formulate the elastic properties and their relations to the crystal orientation. Hence, this chapter first summarizes some basic definitions and calculation rules for Rotation matrices, including the definition of the Euler angles, which are most commonly used to define the relative orientations of the crystal and the component. Parts of this chapter closely follow the lines of the excellent exposition of the topic by Olschewski.
KW - Nickel-base superalloys
KW - Elasticity
PY - 2022
SN - 978-0-12-819357-0
SP - 41
EP - 67
PB - Elsevier Inc.
AN - OPUS4-53435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.
A1 - Camin, B.
A1 - Hansen, L.
A1 - Heuser, M.
A1 - Lopez-Galilea, I.
A1 - Ruttert, B.
A1 - Theisen, W.
A1 - Fedelich, Bernard
T1 - Refinement and Experimental Validation of a Vacancy Model of Pore Annihilation in Single-Crystal Nickel-Base Superalloys during Hot Isostatic Pressing
N2 - Initially, as-cast and homogenized single crystals of nickel-base superalloy CMSX-4 are subjected to hot isostatic pressing at 1288 °C. Two series of experiments are conducted: under the same pressure of 103 MPa but with different durations, between 0.5 and 6 h, and under different pressures, between 15 and 150 MPa, but for the same time of 0.5 h. The porosity annihilation is investigated metallographically and by high-resolution synchrotron X-ray tomography. The obtained experimental results are compared with the predictions of the vacancy model proposed recently in the group. Herein, the model is further refined by coupling with X-ray tomography. The model describes the evolution of the pore arrays enclosed in the 3D synchrotron tomograms during hot isostatic pressing and properly predicts the time and stress dependences of the pore annihilation kinetics. The validated model and the obtained experimental results are used for selecting the optimal technological parameters such as applied pressure and processing time
KW - Superalloys
KW - HIP
KW - Single-Crystal
KW - Diffusion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526859
DO - https://doi.org/10.1002/adem.202100211
VL - 23
IS - 7
SP - 211
AN - OPUS4-52685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmadian, A.
A1 - Scheiber, D.
A1 - Zhou, X.
A1 - Gault, B.
A1 - Darvishi Kamachali, Reza
A1 - Romaner, L.
A1 - Ecker, W.
A1 - Dehm, G.
A1 - Liebscher, C. H.
T1 - Interstitial segregation has the potential to mitigate liquid metal embrittlement in iron
N2 - The embrittlement of metallic alloys by liquid metals leads to catastrophic material failure and severely impacts their structural integrity. The weakening of grain boundaries by the ingress of liquid metal and preceding segregation in the solid are thought to promote early fracture. However, the potential of balancing between the segregation of cohesion-enhancing interstitial solutes and embrittling elements inducing grain boundary decohesion is not understood. Here, we unveil the mechanisms of how boron segregation mitigates the detrimental effects of the prime embrittler, zinc, in a Σ5 [0 0 1] tilt grain boundary in α −Fe (4 at.% Al). Zinc forms nanoscale segregation patterns inducing structurally and compositionally complex grain boundary states. Ab-initio simulations reveal that boron hinders zinc segregation and compensates for the zinc induced loss in grain boundary cohesion. Our work sheds new light on how interstitial solutes intimately modify grain boundaries, thereby opening pathways to use them as dopants for preventing disastrous material failure.
KW - Materials Modelling
KW - Liquid Metal Embrittlement
KW - Alloy Safety
KW - CALPHAD
KW - Microstructure Design
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573576
DO - https://doi.org/10.1002/adma.202211796
SN - 0935-9648
IS - e2211796
PB - Wiley online library
AN - OPUS4-57357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Agudo Jácome, Leonardo
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Fries, S. G.
T1 - Data regarding the experimental findings compared with CALPHAD calculations of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy
N2 - This contribution contains the raw data used to compare experimental results with thermodynamic calculations using the CALPHAD method, which is related to the research article “The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: experimental findings and comparison with calculations using the CALPHAD method” [1] , and therefore this article can be used as a basis for interpreting the data contained therein. The AlMo0.5NbTa0.5TiZr refractory superalloy was characterized in the cast and annealed condition (1400 °C for 24 h) in order to measure grain size and to identify and measure the size and area fraction of the phases present. The raw data of this article include X-ray diffraction (XRD) measurements, microstructural characterization by scanning and transmission electron microscopy (SEM and TEM), and elemental analysis by energy dispersive X-ray spectroscopy (EDX). XRD includes the determination of phases and the lattice parameters (A2, B2, and hexagonal structure). Microstructural analysis by scanning and transmission electron microscopy includes (1) identification of composition, size, and volume fraction of the present phases and (2) determination of grain size. Based on these experimental data, it is possible to identify similarities and discrepancies with the data calculated using the CALPHAD method for the alloy under study in Ref. [1] , which provides the basis for better and more efficient development of reliable databases.
KW - Transmission electron microscopy
KW - Scanning electron microscopy
KW - Microstructural characterization
KW - Refractory high entropy alloys
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568009
DO - https://doi.org/10.1016/j.dib.2022.108858
SN - 2352-3409
VL - 46
SP - 1
EP - 19
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kianinejad, Kaveh
A1 - Darvishi Kamachali, Reza
A1 - Khedkar, Abhinav
A1 - Manzoni, Anna Maria
A1 - Agudo Jácome, Leonardo
A1 - Schriever, Sina
A1 - Saliwan Neumann, Romeo
A1 - Megahed, Sandra
A1 - Heinze, Christoph
A1 - Kamrani, Sepideh
A1 - Fedelich, Bernard
T1 - Creep anisotropy of additively manufactured Inconel-738LC: Combined experiments and microstructure-based modeling
N2 - The current lack of quantitative knowledge on processing-microstructure–property relationships is one of the major bottlenecks in today’s rapidly expanding field of additive manufacturing. This is centrally rooted in the nature of the processing, leading to complex microstructural features. Experimentally-guided modeling can offer reliable solutions for the safe application of additively manufactured materials. In this work, we combine a set of systematic experiments and modeling to address creep anisotropy and its correlation with microstructural characteristics in laser-based powder bed fusion (PBF-LB/M) additively manufactured Inconel-738LC (IN738LC). Three sample orientations (with the tensile axis parallel, perpendicular, and 45° tilted, relative to the building direction) are crept at 850 °C, accompanied by electron backscatter secondary diffraction (EBSD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations. A crystal plasticity (CP) model for Ni-base superalloys, capable of modeling different types of slip systems, is developed and combined with various polycrystalline representative volume elements (RVEs) built on the experimental measurements. Besides our experiments, we verify our modeling framework on electron beam powder bed fusion (PBF-EB/M) additively manufactured Inconel-738LC. The results of our simulations show that while the crystallographic texture alone cannot explain the observed creep anisotropy, the superlattice extrinsic stacking faults (SESF) and related microtwinning slip systems play major roles as active deformation mechanisms. We confirm this using TEM investigations, revealing evidence of SESFs in crept specimens. We also show that the elongated grain morphology can result in higher creep rates, especially in the specimens with a tilted tensile axis.
KW - Additive manufactured Ni-base superalloys
KW - Creep
KW - Crystal plasticity
KW - Superlattice extrinsic stacking faults
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601576
DO - https://doi.org/10.1016/j.msea.2024.146690
SN - 0921-5093
VL - 907
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-60157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Fries, S. G.
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Roik, J.
A1 - Agudo Jácome, Leonardo
T1 - The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: Experimental findings and comparison with calculations using the CALPHAD method
N2 - Detailed microstructural characterization of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy in the as-cast state is reported for first time and compared with the state annealed at 1400 oC for 24 h. The former shows a dendritic structure, with a mixture of A2/B2 phases < 20 nm in both the dendritic and interdendritic regions. A mostly amorphous phase, rich in Al and Zr, is found within the interdendritic region. The annealed state reproduced the combination of A2/B2/Al-Zr-rich phases reported previously. Calculations from two relevant ThermoCalc databases were compared with the experimental results. Equilibrium calculations were compared with results for the annealed alloy, whereas solidification paths calculated using Scheil-Gulliver model were used for comparison with the as-cast alloy. A previously hypothesized spinodal decomposition during cooling as the mechanism responsible for the patterned A2/B2 microstructure is confirmed via the CALPHAD calculations, pointing to its use as an efficient design tool for such alloys. Finally, the comparison between the experimental and computational findings allowed better understanding the solidification path and equilibrium stability of this alloy, giving a base to make better decisions on the field of new refractory superalloy design.
KW - CALPHAD database analysis
KW - Refractory superalloys
KW - Chemically complex alloy
KW - Characterization
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545906
DO - https://doi.org/10.1016/j.matdes.2022.110593
SN - 1873-4197
VL - 217
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xing, H.
A1 - Jing, H.
A1 - Dong, X.
A1 - Wang, Lei
A1 - Han, Y.
A1 - Hu, R.
T1 - Cellular growth during rapid directional solidification: Insights from quantitative phase field simulations
N2 - In this paper, columnar cellular growth with kinetic effects including kinetic undercooling and solute trapping in rapid directional solidification of alloys was investigated by using a recent quantitative phase-field model for rapid solidification. Morphological transition and primary spacing selection with and without kinetic effects were numerically investigated. Numerical results show that doublon structure is an intermediate state in the primary spacing adjustment of cellular arrays. It was found that the inclusions of kinetic effects result in the increase of the solute in the solid phase and the solute enrichment in the interdendritic liquid channel. Moreover, predicted results indicate that the growth directions of the cellular arrays in rapid directional solidification with and without kinetic effects are independent of the Péclet number. Therefore, the kinetic effects play important roles in numerical simulations of the growth pattern selection and solute distribution during rapid solidification. Neglecting them will result in the inaccurately predicted results.
KW - Rapid solidification
KW - Phase-field model
PY - 2022
DO - https://doi.org/10.1016/j.mtcomm.2022.103170
VL - 30
SP - 103170
PB - Elsevier Ltd.
AN - OPUS4-54571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gesell, Stephan
T1 - Numerical calculation of ΔCTOD for thermomechanical fatigue crack growth
N2 - The cyclic crack tip opening displacement ΔCTOD is a promising loading Parameter to quantify the crack propagation under thermomechanical fatigue (TMF). In this work, suitable techniques are investigated and compared for an accurate calculation of ΔCTOD under TMF loading using a viscoplastic temperature dependent material model.
It turned out that collapsed special crack tip elements give the best results. An efficient FEM-technique is developed to simulate the incremental crack growth by successive remeshing, whereby the deformations and internal state variables are mapped from the old mesh onto the new one. The developed techniques are demonstrated and discussed for two-dimensional examples like TMF-specimens. Recommendations are made regarding important numerical control parameters like optimal size of crack tip elements, length of crack growth increment in relation to plastic zone size and ΔCTOD value.
T2 - ESIS Technical Meeting on Numerical Methods (TC8)
CY - Online meeting
DA - 06.04.2021
KW - Crack tip opening displacement
KW - Thermomechanical fatigue
KW - Crack growth
PY - 2021
AN - OPUS4-52410
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ganesh, Rahul
A1 - Gesell, Stephan
A1 - Kuna, M.
A1 - Fedelich, Bernard
A1 - Kiefer, B.
T1 - Numerical calculation of ΔCTOD for thermomechanical fatigue crack growth
N2 - The cyclic crack tip opening displacement ΔCTOD is a promising loading Parameter to quantify the crack propagation under thermomechanical fatigue (TMF). In this work, suitable techniques are investigated and compared for an accurate calculation of ΔCTOD under TMF loading using a viscoplastic temperature dependent material model.
It turned out that collapsed special crack tip elements give the best results. An efficient FEM-technique is developed to simulate the incremental crack growth by successive remeshing, whereby the deformations and internal state variables are mapped from the old mesh onto the new one. The developed techniques are demonstrated and discussed for two-dimensional examples like TMF-specimens. Recommendations are made regarding important numerical control parameters like optimal size of crack tip elements, length of crack growth increment in relation to plastic zone size and ΔCTOD value.
N2 - Zur Bewertung des Rissfortschritts unter thermomechanischer Ermüdung (TMF) ist die zyklische Rissöffnungsverschiebung ΔCTOD ein aussichtsreicher bruchmechanischer Beanspruchungsparameter. In dieser Arbeit werden unter Anwendung eines viskoplastischen, temperaturabhängigen Materialmodells geeignete FEM-Techniken für die akkurate Berechnung des ΔCTOD bei TMF erprobt und verglichen. Als beste Technik hat sich die Verwendung kollabierter Rissspitzenelemente erwiesen. Es wurde ein effizienter FEM-Algorithmus zur Simulation der Rissausbreitung mit inkrementeller Neuvernetzung entwickelt, bei dem die Verformungen und inelastischen Zustandsvariablen jeweils vom alten auf das neue Netz übertragen werden. Die erarbeiteten Techniken werden am Beispiel von zweidimensionalen Strukturen und TMF-Proben vorgestellt und diskutiert. Dabei werden wesentliche Kontrollparameter der Simulation wie optimale Grösse der Rissspitzenelemente, Länge des Rissinkrementes in Relation zur plastischen Zone und dem ΔCTOD-Wert empfohlen.
T2 - 53. Tagung des Arbeitskreises "Bruchmechanik und Bauteilsicherheit"
CY - Online meeting
DA - 18.02.2021
KW - Crack tip opening displacement
KW - Thermomechanical fatigue
KW - Crack growth
PY - 2021
SP - 1
EP - 10
PB - DVM (Deutscher Verband für Materialforschung und -prüfung)
CY - Berlin
AN - OPUS4-52519
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ganesh, R.
A1 - Gesell, Stephan
A1 - Fedelich, Bernard
A1 - Kuna, Meinhard
A1 - Kiefer, B.
T1 - Procrackplast: Eine Software zur Simulation des 3D-Risswachstums unter großen plastischen Deformationen
T1 - Procrackplast: A software for simulating 3D crack growth under large plastic deformation
N2 - The finite element software ProCrackPlast is developed for the automated simulation of fatigue crack growth in arbitrarily loaded three-dimensional components with large scale plastic deformations, in particular under cyclic thermomechanical (TMF) loading.
ProCrackPlast is developed by extending the software Procrack, created at TU Freiberg for linear-elastic crack growth simulations. The pre-processing, FEM analysis, and the post-processing in ProCrackPlast are done by the commercial software ABAQUS. ProCrackPlast resorts to a crack growth procedure which adaptively updates the crack in finite increments based on the fracture-mechanical parameter, cyclic crack tip opening displacement ΔCTOD . Features of this software along with two application examples of fatigue crack growth in a typical cast steel, Ni-Resist, are presented in this paper to show its capability and performance.
N2 - Es wird die Finite-Element-Software ProCrackPlast vorgestellt, die eine automatische Simulation der Ermüdungsrissausbreitung in beliebig belasteten dreidimensionalen Bauteilen mit größeren plastisch verformten Bereichen ermöglicht, insbesondere bei thermomechanischer Wechselbelastung (TMF). ProCrackPlast entstand durch Erweiterung des Programs ProCrack, das an der TU Freiberg für linear-elastische inkrementelle Rissfortschrittsanalysen entwickelt wurde. Das Pre-Processing, die FEM Analyse und das Post-Processing werden mit Hilfe der kommerziellen FE-Software ABAQUS durchgeführt.
ProCrackPlast beruht auf einem Algorithmus, mit dem der Rissfortschritt adaptiv in endlichen Inkrementen unter Verwendung des bruchmechanischen Parameters der zyklischen Rissöffnungsverschiebung ΔCTOD gesteuert wird. Die Funktionseigenschaften dieser Software werden anhand von zwei Anwendungsbeispielen zum Ermüdungsrisswachstum für einen typischen Stahlguss, Ni-Resist, exemplarisch dargestellt, um die Möglichkeiten und Leistungsfähigkeit von ProCrackPlast zu demonstrieren.
T2 - 54. Tagung des Arbeitskreises "Bruchmechanik und Bauteilsicherheit"
CY - Online meeting
DA - 22.02.2021
KW - Automated finite element analysis
KW - Automatische Finite Element Simulation
KW - Thermomechanical fatigue
KW - Crack growth
KW - Thermomechanische Ermüdung
KW - Rissausbreitung
PY - 2022
SP - 205
EP - 214
PB - Deutscher Verband für Materialforschung und -prüfung e.V.
AN - OPUS4-54435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ferrari, Bruno
T1 - Microstructural evolution of PBF-LB/M Inconel 718 during solution-aging heat treatments - an in-situ x-ray diffraction study
N2 - Inconel 718 (IN718) is a traditional age-hardenable nickel-based alloy that has been increasingly processed by additive manufacturing (AM) in recent years. In the as-solidified condition, IN718 exhibits chemical segregation and the undesired Laves phase, requiring a solution annealing (SA) prior to aging. The material produced by AM does not respond to the established thermal routines in the same way as conventionally produced IN718, and there is still no consensus on which routine yields optimal results. This work aims to provide a fundamental understanding of the heat treatment (HT) response by continuously monitoring the microstructural evolution during SA via time-resolved synchrotron x-ray diffraction, complemented by ex-situ scanning electron microscopy (SEM). The samples were produced by laser powder bed fusion to a geometry of 10x20x90 mm³, from which Ø1x5 mm³ cylindric specimens were extracted. Two different scanning strategies – incremental 67° rotations, Rot, and alternating 0°/67° tracks, Alt – were used, leading to two different as-built conditions. 1-hour SAs were carried out in the beamline ID22 of the ESRF at 50 KeV. Two SA temperatures, SA1 = 1020 °C, and SA2 = 1080 °C were tested for each scanning strategy. Data were processed using the software PDIndexer. In the as-built state, all samples showed typical subgrain columnar cell structures with predominant Nb/Mo segregation and Laves phase at the cell walls, as seen by SEM. The Alt scan induced higher intensity on the Laves peaks than the Rot scan, suggesting a greater content of Laves. Chemical homogenization in the SA was largely achieved during the heating ramp (Fig. 1). SA2 eliminated the Laves peaks just before reaching 1080 °C, and mitigated differences between Rot and Alt samples. On the other hand, SA1 induced the precipitation of the generally detrimental δ phase, also observed by SEM. Furthermore, the Rot scan showed higher δ peak intensities than the Alt scan, indicating a higher content of δ in the latter. No signs of recrystallization were observed in any of the investigated SAs.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Additive Manufacturing
KW - X-Ray Diffraction
KW - Inconel 718
KW - Heat Treatments
KW - Microstructure
PY - 2023
AN - OPUS4-58392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ruffini, A.
A1 - Le Bouar, Y.
A1 - Finel, A.
A1 - Epishin, A. I.
A1 - Fedelich, Bernard
A1 - Feldmann, Titus
A1 - Viguier, B.
A1 - Poquillon, D.
T1 - Dislocations interacting with a pore in an elastically anisotropic single crystal nickel-base superalloy during hot isostatic pressing
N2 - The formation of pores in CMSX-4 nickel based superalloys is detrimental to the service life of the material. A way to avoid the problem is to treat the superalloys under Hot Isostatic Pressing (HIP), which enables a large volume fraction of pores to be annihilated. This paper aims to understand the contribution of plastic activity related to the gliding of dislocations on the pore annihilation. Simulations based on a phase-field model of dislocation are performed and make it possible to consider the strong anisotropy of the CMSX-4 under HIP conditions in conjunction to the strong elastic heterogeneity introduced by the pore. For pores with a radius of few micrometers, it is shown that edge parts of dislocation lines that present an extra half atomic plane oriented towards the pore are stacked above and under it in the direction which is perpendicular to their slip-planes, causing an increase of the number of dislocation along the four octahedral directions of the FCC single crystal which intersect the pore center. Results are streamlined within the isotropic elastic theory of dislocations. Effects of elastic anisotropy and dislocation reactions are also investigated in order to specify what would be the dislocation configuration around a pore in CMSX-4 under HIP conditions. Notably, the elastic anisotropy is shown to significantly modify the arrangement of dislocations close to the pore equator. Simulations also allow for the characterization of pore/dislocation interactions when dislocations are involved in Low Angle Boundaries as experimentally observed.
KW - HIP
KW - Superalloys
KW - Dislocation
KW - Pore
KW - Phase-field
PY - 2022
DO - https://doi.org/10.1016/j.commatsci.2021.111118
SN - 0927-0256
VL - 204
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tabin, J.
A1 - Kawałko, J.
A1 - Schob, Daniela
A1 - Roszak, R.
A1 - Brodecki, A.
A1 - Bała, P.
A1 - Maasch, philipp
A1 - Kowalewski, Z.
A1 - Ziegenhorn, M.
T1 - Deformation-induced martensitic transformation in fused filament fabrication austenitic stainless steels during tension at wide range of temperatures (77 K, RT)
N2 - This study investigates the mechanical behaviour of fused filament fabrication (FFF) of 316L austenitic stainless steel compared to conventional 316L at room temperature and 77 K, focusing on deformation-induced martensitic transformation (DIMT). Results reveal that the Lüders-like effect, present in conventional 316L at 77 K, is absent in FFF 316L due to porosities that hinder martensitic front propagation. At room temperature, uniform strain distribution and DIMT were observed in conventional 316L, whereas in FFF 316L, martensitic nucleation occurred around pores, serving as a localized strengthening mechanism. Microstructural analysis identified Fe-δ islands along grain boundaries in FFF 316L, which contribute to its multiphase nature. Although FFF 316L demonstrates lower yield stress and elongation compared to conventional 316L, this study does not establish design allowables. The present findings are limited to monotonic tensile behaviour, fatigue performance and corrosion resistance under cryogenic conditions were not assessed. Further optimization of fabrication parameters to minimize ferrite content and porosities is suggested to enhance mechanical performance.
KW - TRIP effect
KW - Fused filament fabrication
KW - 316L
KW - Cryogenic
KW - Cryogenic temperatures
KW - Microstructure
PY - 2026
DO - https://doi.org/10.1016/j.msea.2025.149552
SN - 0921-5093
VL - 950
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Santos Baltieri, Ricardo
T1 - Luminescence Thermometry in Pure TeO₂ Glasses Doped with Er3+/Yb3+ and Eu3+: Remote Sensing Capability Across the Biological Temperature Range
N2 - The development of non-contact and remote temperature sensors based on rare-earth (RE3+)-doped glasses is crucial for emerging applications in biomedical diagnostics and microscale thermal monitoring. In this study, we explore the fundamental thermometric properties of pure tellurite (TeO2) glasses doped with either Er3+/Yb3+ or Eu3+ ions in a wide range of temperature. The Er3+/Yb3+-co-doped system was analyzed through upconversion emission thermometry, particularly involving thermally coupled levels 2H11/2 and 4S3/2. The intensity ratio between these levels exhibits a clear temperature dependence from 100 K to 530 K, with an inversion near 160 K and optimal sensitivity above 250 K. At 300 K, the relative sensitivity (SR) reached 1.1% K−1, and the absolute sensitivity peaked at 6.5 × 10−3 K−1 at 460 K. Figure on the left is the Er3+ upconversion luminescence dependency on temperature, in the center is the excitation spectra of Eu3+ with temperature, and on the right is the comparison between calculated and measured temperature for Eu3+ samples. In parallel, the excitation spectra of Eu3+-doped TeO2 glasses were acquired from 100 K to 520 K, revealing three thermally responsive spectral regions. These transitions exhibited temperature-dependent intensity inversions, enabling the use of excitation-based thermometry. Notably, one of the regions provided the most accurate temperature predictions, with a relative sensitivity of 0.5% K−1 at 300 K. Both systems benefit from the high optical transparency, chemical stability, and low phonon energy of pure TeO2 glass, making them ideal candidates for remote sensing platforms, such as fiber-optic tips or implantable probes. While the Er3+/Yb3+ system provides robust upconversion emission for conventional thermometry, the Eu3+ system introduces an innovative excitation-based strategy, broadening the applicability of RE3+-doped tellurite glasses for optical thermometry.
Acknowledgements
This work was supported by the São Paulo Research Foundation (FAPESP – N. 2020/11038-2, 2023/05994-6, 2024/04675-7) and National Council for Scientific and Technological Development (CNPq - 304718/2023-8).
T2 - Shift 2025 Conference
CY - Tenerife, Spain
DA - 13.10.2025
KW - Lanthanide
KW - Optical thermometry
KW - Energy conversion
PY - 2025
AN - OPUS4-65195
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy conversion of waste heat using thermomagnetic materials
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. We demonstrated that guiding the magnetic flux with a pretzel-type topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude [1]. From an ideal material’s perspective, several similarities with magnetocaloric materials [2] can be found, like a sharp first-order like magnetostructural transition, low hysteresis and high thermal diffusivity. This makes some magnetocaloric materials good candidates also for thermomagnetic energy harvesting, like e.g. (MnFe)2P-based and La(Fe,Si)13-based compounds.
Recently, the EU MSCA initial training network Heat4Energy [2] was started with the aim of making three thermomagnetic energy converters for low grade waste heat (<100°C) to electricity with different power output ranges. While the smallest demonstrator operates with thin film materials, the two larger machines use bulk material, for which different processing and shaping routes are explored. In collaboration with the industrial stakeholders of the project, up-scalability and practical application issues of materials processing will be addressed during the project. After an introduction into the technological background and the ITN project, we will present first results on 3D printing and non-destructive imaging of the thermomagnetic parts.
T2 - Advances in Magnetics (AIM) 2025
CY - Bressanone, Italy
DA - 10.02.2025
KW - Energy harvesting
KW - Thermomagnetic energy conversion
KW - Magnetic materials
PY - 2025
AN - OPUS4-65201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy conversion of waste heat using thermomagnetic materials
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. We demonstrated that guiding the magnetic flux with a pretzel-type topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude [1]. From an ideal material’s perspective, several similarities with magnetocaloric materials [2] can be found, like a sharp first-order like magnetostructural transition, low hysteresis and high thermal diffusivity. This makes some magnetocaloric materials good candidates also for thermomagnetic energy harvesting, like e.g. (MnFe)2P-based and La(Fe,Si)13-based compounds.
Recently, the EU MSCA initial training network Heat4Energy [2] was started with the aim of making three thermomagnetic energy converters for low grade waste heat (<100°C) to electricity with different power output ranges. While the smallest demonstrator operates with thin film materials, the two larger machines use bulk material, for which different processing and shaping routes are explored. In collaboration with the industrial stakeholders of the project, up-scalability and practical application issues of materials processing will be addressed during the project. After an introduction into the technological background and the ITN project, we will present first results on 3D printing and non-destructive imaging of the thermomagnetic parts. Furthermore, we will review criticality issues of materials employed in this new technology.
T2 - MRS Spring Meeting Seattle
CY - Seattle, WA, USA
DA - 07.04.2025
KW - Energy harvesting
KW - Magnetic materials
KW - Thermomagnetic energy conversion
PY - 2025
AN - OPUS4-65198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - Energy conversion of waste heat using thermomagnetic materials
N2 - To date, there are very few technologies available for the conversion of low-temperature waste heat into electricity. Thermomagnetic generators are one approach proposed more than a century ago. Such devices are based on a cyclic change of magnetization with temperature. This switches a magnetic flux and, according to Faraday’s law, induces a voltage. We demonstrated that guiding the magnetic flux with a pretzel-type topology of the magnetic circuit improves the performance of thermomagnetic generators by orders of magnitude [1]. From an ideal material’s perspective, several similarities with magnetocaloric materials [2] can be found, like a sharp first-order like magnetostructural transition, low hysteresis and high thermal diffusivity. This makes some magnetocaloric materials good candidates also for thermomagnetic energy harvesting, like e.g. (MnFe)2P-based and La(Fe,Si)13-based compounds.
Recently, the EU MSCA initial training network Heat4Energy [2] was started with the aim of making three thermomagnetic energy converters for low grade waste heat (<100°C) to electricity with different power output ranges. While the smallest demonstrator operates with thin film materials, the two larger machines use bulk material, for which different processing and shaping routes are explored. In collaboration with the industrial stakeholders of the project, up-scalability and practical application issues of materials processing will be addressed during the project. After an introduction into the technological background and the ITN project, we will present first results on 3D printing and non-destructive imaging of the thermomagnetic parts. Furthermore, we will review criticality issues of materials employed in this new technology.
T2 - MRS Fall Meeting Boston
CY - Boston, MA, USA
DA - 01.12.2025
KW - Energy harvesting
KW - Thermomagnetic energy conversion
KW - Magnetic materials
PY - 2025
AN - OPUS4-65197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Comparative residual stress analysis on a DED-Arc manufactured high-strength steel component using the contour method and XRD
N2 - Lightweight construction is a vital approach for reducing CO₂ emissions. It contributes to the development of more energy-efficient structures and supports the overall goal of achieving carbon neutrality in the transition to sustainable manufacturing. Thus, a topology-optimized design often leads to complex geometries. Additive manufacturing (AM) processes such as direct energy deposition with arc (DED-Arc) offers a great design freedom due to the build-up of components in layers. Furthermore, they enable efficient production due to the high deposition rate, process reliability and good automation capability. Further efficiency can be achieved through weight optimization, enabled by high-strength steels. However, a major challenge is the process induced residual stresses (RS) in the component. High tensile residual stresses are detrimental as they increase the risk of cold cracking. Knowledge of residual stress distribution is crucial for predicting service life of the component and structural integrity assessment, especially for safety critical applications. Therefore, this study focuses on the use of Contour method (CM) to analyse the full field longitudinal residual stresses in an open hollow cuboid component (dimensions: 120 x 50 x 30 mm3) manufactured by DED-Arc (yield strength > 730 MPa). In the contour method, the component is cut along a desired plane of interest and the contour of deformed cut surface is measured. A finite element model is used to reconstruct the residual stresses field in the 2-dimensional plane of cut. In this paper a modified cutting strategy was employed, post cutting the deformed cut surfaces were measured utilizing two surface measurement techniques i.e., coordinate measuring machine (CMM) and a 3D Scanner. The accuracy of the contour method was validated against surface stresses measured using X-ray diffraction. Additionally, a comparison of neutron diffraction experiments was conducted. The residual stresses were further correlated with hardness measurements. The results from surface measurement techniques showed good agreement regarding the measured displacement contours and the contour method results revealed peak stresses in the DED-Arc walls, bending deformation in substrate induces tensile stresses at the bottom of the substrate plate and compressive stresses in the middle top region. The residual stresses obtained from diffraction and contour method showed a good agreement and correlated qualitatively with the hardness measurements.
T2 - 78th IIW Annual Assembly and International Conference on Welding and Joining
CY - Genoa, Italy
DA - 22.06.2025
KW - Residual stress
KW - Contour method
KW - DED-Arc/M
KW - High-strength steel
KW - Filler metals
KW - XRD
KW - Neutron diffraction
PY - 2025
AN - OPUS4-65215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Residual stress evaluation using the contour method of an additive manufactured high-strength steel solid cuboid
N2 - Direct Energy Deposition with Arc (DED-Arc) enables the weight-optimized and near-net-shape manufacturing of complex structures. Lightweight construction principles allow a reduction of CO2 emissions by saving time, costs, and resources. Further optimisations can be achieved by using high-strength steel. This allows for a reduction in wall thickness and optimisation of weight. However, manufacturing intricate geometries using high-strength steels poses challenges in managing residual stresses (RS), which are essential for ensuring the structural integrity of welded components. High residual stresses can increase the risk of cold cracking, arising from the complex interactions between material properties, process conditions, and component design. Despite the availability of suitable filler metals, the lack of comprehensive knowledge and guidelines on residual stress formation limits the industrial application.
Therefore, in the present study, the contour method (CM) was used to analyse the full field longitudinal residual stresses in an solid cuboid component (dimensions: 120 × 50 × 35 mm³) manufactured by DED-Arc. The CM enables the analysis of the two-dimensional map of residual stresses normal to a cutting plane using a finite element model. For this purpose, a solid cuboid component was welded fully automatically with a high-strength solid wire specially adapted for DED-Arc (yield strength > 790 MPa) onto conventionally manufactured substrates made of S690QL. The residual stresses from CM in the volume are compared with residual stress analyses using X-Ray diffraction on the surface. Additionally, comparative data from previous studies on hollow cuboid structures was included in order to identify similarities and differences in the resulting stress state, and to complement and validate the CM results. These results demonstrate the significant influence of the geometry on the residual stress profiles within the solid cuboid in relation to the open hollow.
T2 - 4th International Conference on Advanced Joining Processes 2026
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Residual stress
KW - Contour method
KW - DED-Arc/M
KW - High-strength steel
KW - Filler metals
KW - Neutron diffraction
PY - 2025
AN - OPUS4-65209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique authenticator for additively manufactured parts derived from their microstructure
N2 - The international research community is currently devoting extensive resources to the development of digital material data spaces and the associated digital twins and product passports of materials and components. A common weak link in these projects to date has been the connection between physical components / samples and their digital data and documents. This is where the concept of the unique identification comes in. Components produced using additive manufacturing can be marked for unique identification and secure authentication [1,2]. Serial numbers and machine-readable codes can be used to identify the component, and link digital product-related data (i.e., a digital product passport) to the actual components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface or the internal cavity of hollow components. However, local manipulation of components may alter the properties, and external tagging features can be altered or even removed by post-processing treatments.
This work provides a new methodology for identification, authentication, and traceability of additively manufactured (AM) components using microstructural features that are unique to each part. X-ray computed tomography (XCT) was employed to image the microstructural features of a batch of AlSi10Mg parts. Based on size and geometry, the most prominent features were selected to create a unique digital authenticator. We implemented a framework in Python using open-access modules that can successfully create a digital object authenticator using the segmented microstructure information from XCT. We show that this method allows to authenticate individual parts from the build job based on its microstructural fingerprint. This is our contribution to enhancing the security and product protection of additively manufactured components.
T2 - FEMS EUROMAT
CY - Granada, Spain
DA - 15.09.2025
KW - Authentication
KW - Fingerprint
KW - Non-destructive testing
PY - 2025
AN - OPUS4-65202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waske, Anja
T1 - A unique authenticator for additively manufactured parts derived from their microstructure
N2 - Components produced using additive manufacturing can be marked for unique identification and secure authentication [1,2]. Serial numbers and machine-readable codes can be used to identify the component, and link digital product-related data (i.e., a digital product passport) to the actual components. The most prevailing solution consists of local process manipulation, such as printing a quick response (QR) code [3] or a set of blind holes on the surface of the internal cavity of hollow components. However, local manipulation of components may alter the properties, and external tagging features can be altered or even removed by post-processing treatments. This work therefore aims to provide a new methodology for identification, authentication, and traceability of additively manufactured (AM) components using microstructural features that are unique to each part. X-ray computed tomography (XCT) was employed to image the microstructural features of AlSi10Mg parts. Based on size and geometry, the most prominent features were selected to create a unique digital authenticator. We implemented a framework in Python using open-access modules that can successfully create a digital object authenticator using the segmented microstructure information from XCT. The authenticator is stored as a QR code, along with the 3D information of the selected features.
T2 - MRS Spring Meeting Seattle
CY - Seattle, WA, USA
DA - 07.04.2025
KW - Additive Manufacturing
KW - Fingerprint
KW - Non-destructive testing
PY - 2025
AN - OPUS4-65199
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witte, Julien
T1 - The Impact of Ultrasonic-Assisted Milling and Alloying Elements on the Surface Integrity of Additively Manufactured Iron Aluminides
N2 - The increasing focus on energy and resource efficiency has driven the implementation of additive manufacturing (AM) of high-performance materials, particularly in lightweight constructions with optimization of material efficiency. Iron aluminides (FeAl) hold great potential due to their low density, excellent corrosion and wear resistance, high-temperature stability, and vast availability. However, the inherent heterogeneity and anisotropy of FeAl-AM structures pose significant challenges, especially regarding hardness and brittleness. These material characteristics complicate the mostly necessary post-processing via mechanical finish machining, often resulting in elevated cutting forces, accelerated tool wear, and suboptimal surface integrity. Ultrasonic-assisted milling (USAM), a hybrid machining process, offers significant advantages over conventional milling (CM), including the reduction of cutting forces and tool wear. Notably, USAM has been demonstrated to decrease surface defect density and mitigate tensile residual stresses, while potentially inducing beneficial compressive residual stresses within the depth profile of the component’s surface. These effects can significantly enhance crack propagation resistance, improve corrosion behavior, and extend the fatigue life of components in safety-relevant applications. The present study investigates the effects of additional alloying elements such as molybdenum, nickel, titanium and Vanadium in FeAl as well as milling parameters, including cutting speed vc and feed rate fz, on the surface integrity with special regard to residual stress formations.
T2 - BMDK der OvGU Magdeburg
CY - Magdeburg, Germany
DA - 10.12.2025
KW - Additive Manufacturing
KW - Wear Protection
KW - Ultrasonic-assisted Milling
KW - Iron-aluminides
KW - MPEA
KW - Surface Integrity
KW - Residual Stresses
PY - 2025
AN - OPUS4-65234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nikoonasab, Ali
T1 - Electrochemical study of steel reinforcement in the synthetic pore solution of alkali-activated binders: Pore solution composition
N2 - It is well known that cement manufacture, including CaCO3 calcination and clinker formation, is associated with substantial energy consumption and significant greenhouse gas emissions. Alkali-activated binders (AAB) and concretes made from them can significantly contribute to reducing CO2 emissions caused by the construction industry. However, to what extent and for how long concretes made from AAB can protect the steel in reinforced concrete components from corrosion is still unclear. Unlike PC-based binders, AABs are made by reacting alkaline solutions with solid precursors such as fly ash and ground granulated blast furnace slag (GGBFS). Therefore, steel reinforcement corrosion mechanisms in AAMs differ from PC-based binders. The present study aims to evaluate the corrosion behavior of steel rebar in alkali-activated materials (AAMs) synthetic pore solution with different chemical concentrations representing different GGBFS and Flay Ash based binders by performing electrochemical tests to measure the corrosion rate and corrosion potential of steel rebar. This information can be used to improve the design of AAMs in order to ensure a longer service life for these materials.
T2 - Eurocorr2023
CY - Brussels, Belgium
DA - 27.08.2023
KW - GGBFS
KW - AAM
KW - Sulfide
KW - Pore solution composition
KW - Redox potential
KW - Corrosion
PY - 2023
AN - OPUS4-59090
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Graebner, Maraike
A1 - Giese, Marcel
A1 - Lorenz, Svenja
A1 - Treutler, Kai
A1 - Schröpfer, Dirk
A1 - Wesling, Volker
A1 - Kannengießer, Thomas
T1 - Wear resistance of modified NiMoCrSi claddings in relation to the resulting surface machinability via ultrasonic-assisted milling
N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses).
KW - Colmonoy C56
KW - PTA welding
KW - Adhesive wear
KW - Abrasive wear
KW - Ultrasonic-assisted milling process
KW - Surface integrity
KW - Service life and efficiency
KW - Substitution of critical raw materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651530
DO - https://doi.org/10.1016/j.wear.2025.205830
SN - 0043-1648
VL - 571
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65153
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Rossignol, S.
ED - Gluth, Gregor
T1 - Special issue: Alkali-activated materials and geopolymers in ceramics and beyond
N2 - Geopolymers and alkali-activated materials have emerged as a complement, and partly as an alternative, to traditional materials in various applications, such as traditional ceramics, energy saving, waste management, building construction, and filtration. These new materials can play an important role in mitigating climate change and promoting a circular economy, which is one of the reasons why they are being actively researched in many laboratories around the world.
Open Ceramics, the official, peer-reviewed, Open Access journal of the European Ceramic Society, is dedicated to foster this research and is compiling a Special Issue with the title “Alkali-activated and geopolymer materials in ceramics and various applications”. The aim of this Special Issue is to promote new applications, the use of previously underused raw materials, and in particular a better understanding of the chemical and mechanical behavior of these materials.
The scope of the Special Issue includes, but is not limited to, research on the following topics:
- valorization of previously underused raw materials
- a better understanding of established raw materials
- detailed spectroscopic characterization of alkali-activated materials and geopolymers to elucidate their phase assemblage
- the mechanism of formation of the phase(s) that comprise these binders
- control of their mechanical properties
- the effect of fillers/aggregates on their mechanical properties
- their durability under various conditions and the underlying deterioration mechanisms
- special applications and recycling-related considerations.
KW - Alkali-activated materials
KW - Geopolymers
PY - 2021
UR - https://www.sciencedirect.com/journal/open-ceramics/special-issue/10789KQV7BR
SN - 2666-5395
SP - 100013-1
EP - 100184-12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51984
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bernardino, Carolina
T1 - Effortless Antimicrobial Shield: Spray-coated Silica Nanoparticles For Safer High-touch Surfaces
N2 - Functional films with tailored interfacial properties play a pivotal role for the development of next generation surface coatings, particularly in healthcare-related environments. In this contribution, we present a facile spray-coating method for the creation of antimicrobial thin films on high-touch surfaces using mesoporous silica nanoparticles (MSNs) that were specifically functionalized to enable strong adhesion and sustained release of metal-based antimicrobial agents. The process is scalable and addresses key challenges in adhesion control, film homogeneity, and long-term antimicrobial function against a large range of key pathogens responsible for nosocomial infections. Three distinct types of MSNs – bearing amine (MSN-NH₂), carboxy (MSN-COOH), and thiol (MSN-SH) surface groups – were synthesized to optimize both metal ion loading and interactions with polyelectrolyte-based adhesion layers. These surface modifications not only provide chemical handles for Cu²⁺ and Ag⁺ ion coordination but also modulate nanoparticle-substrate interactions and dispersion behavior during film formation. The coating architecture consists of a two-step process: first, spray deposition of polyelectrolyte primers that anchor strongly to stainless steel substrates; second, a nanoparticle layer that bonds electrostatically and chemically to the primer, forming robust films with great surface coverage. The films were characterized to assess structural integrity, adhesion, and functional performance. Transmission electron microscopy (TEM) and N₂ sorption analysis confirmed the mesoporous structure. ATR-FTIR and zeta potential measurements validated surface functionalization and colloidal stability. Environmental SEM revealed conformal coating across the stainless-steel surfaces with uniform nanoparticle distribution. The coating's adhesion strength was maintained through mechanical wiping and simulated wear and abrasion tests, demonstrating film durability relevant in real-world use scenarios. Antimicrobial testing under semi-dry, application-relevant conditions showed excellent performance for Ag⁺-loaded MSN-SH films, inhibiting growth of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. These results highlight the synergistic role of surface chemistry, metal ion loading, and film-substrate adhesion in creating effective and wear-resistant functional coatings. Moreover, these films do not show any cytotoxic properties towards Human Dermal Fibroblasts (HDF). This study contributes new insights into the design of multifunctional films where adhesion, surface functionality, and scalable processing are co-optimized for enhanced performance and shows how combining tailored surface chemistry and wide-ranging antimicrobial activity brings together smart material design for practical and safe use.
T2 - MRS Fall Meeting 2025
CY - Boston, MA, USA
DA - 30.11.2025
KW - Mesoporous silica nanoparticles
KW - Silver
KW - Antimicrobial
KW - Coatings
KW - Thin film
PY - 2025
AN - OPUS4-65150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
T1 - Melting upon Coalescence of Solid Nanoparticles
N2 - The large surface-to-volume ratio of nanoparticles is understood to be the source of many interesting phenomena. The melting temperature of nanoparticles is shown to dramatically reduce compared to bulk material. Yet, at temperatures below this reduced melting point, a liquid-like atomic arrangement on the surface of nanoparticles is still anticipated to influence its properties. To understand such surface effects, here, we study the coalescence of Au nanoparticles of various sizes using molecular dynamics simulations. Analysis of the potential energy and Lindemann index distribution across the nanoparticles reveals that high-energy, high-mobility surface atoms can enable the coalescence of nanoparticles at temperatures much lower than their corresponding melting point. The smaller the nanoparticles, the larger the difference between their melting and coalescence temperatures. For small enough particles and/or elevated enough temperatures, we found that the coalescence leads to a melting transition of the two nominally solid nanoparticles, here discussed in relation to the heat released due to the surface reduction upon the coalescence and the size dependence of latent heat. Such discontinuous melting transitions can lead to abrupt changes in the properties of nanoparticles, important for their applications at intermediate temperatures.
KW - Nanoparticles
KW - Molecular Dynamics
KW - Surface-induced Melting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552183
DO - https://doi.org/10.3390/solids3020025
VL - 3
IS - 2
SP - 361
EP - 373
PB - MDPI
AN - OPUS4-55218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elfetni, Seif
A1 - Darvishi Kamachali, Reza
T1 - PINNs-MPF: A Physics-Informed Neural Network framework for Multi-Phase-Field simulation of interface dynamics
N2 - We present PINNs-MPF framework, an application of Physics-Informed Neural Networks (PINNs) to handle Multi-Phase-Field (MPF) simulations of microstructure evolution. A combination of optimization techniques within PINNs and in direct relation to MPF method are extended and adapted. The numerical resolution is realized through a multi-variable time-series problem by using fully discrete resolution. Within each interval, space, time, and phases/grains are treated separately, constituting discrete subdomains. PINNs-MPF is equipped with an extended multi-networking (parallelization) concept to subdivide the simulation domain into multiple batches, with each batch associated with an independent NN trained to predict the solution. To ensure continuity across the spatio-temporal-phasic subdomains, a Master NN efficiently is to handle interactions among the multiple networks and facilitates the transfer of learning. A pyramidal training approach is proposed to the PINN community as a dual-impact method: to facilitate the initialization of training when dealing with multiple networks, and to unify the solution through an extended transfer of learning. Furthermore, a comprehensive approach is adopted to specifically focus the attention on the interfacial regions through a dynamic meshing process, significantly simplifying the tuning of hyper-parameters, serving as a key concept for addressing MPF problems using machine learning. We perform a set of systematic simulations that benchmark foundational aspects of MPF simulations, i.e., the curvature-driven dynamics of a diffuse interface, in the presence and absence of an external driving force, and the evolution and equilibrium of a triple junction. The proposed PINNs-MPF framework successfully reproduces benchmark tests with high fidelity and Mean Squared Error (MSE) loss values ranging from 10^−6 to 10^−4 compared to ground truth solutions.
KW - Machine learning
KW - PINNs
KW - Phase-field method
KW - Microstructure evolution
KW - Parallel training
KW - Neural networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629740
DO - https://doi.org/10.1016/j.enganabound.2025.106200
SN - 0955-7997
VL - 176
SP - 1
EP - 22
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62974
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elfetni, Seifallah
A1 - Darvishi Kamachali, Reza
T1 - PINNs-MPF: An Efficient Physics-Informed Machine Learning-based Solver for Multi-Phase-Field Simulations using Tensorflow
N2 - This paper introduces PINNs-MPF, a novel Machine Learning-based solver designed for Multi-Phase-Field (MPF) and diffuse interface simulations, offering innovative approaches to address complex challenges in addressing microstructure evolution in polycrystalline materials using Machine Learning. The framework not only surpasses current limitations in handling multi-phase problems but also allows for potential upscaling to tackle more intricate scenarios. Developed in Python, the related code leverages optimized libraries like TensorFlow, showcasing efficiency and potential scalability in materials science and engineering simulations. This framework, integrating advanced techniques such as multi-networking and training optimization, setting a new standard in predictive capabilities and understanding complex physical phenomena.
KW - Machine Learning
KW - Microstructure Simulation
KW - Phase Field
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631917
DO - https://doi.org/10.1016/j.simpa.2025.100753
SN - 2665-9638
VL - 24
SP - 1
EP - 4
PB - Elsevier B.V.
AN - OPUS4-63191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Wei, Y.
A1 - Kühbach, M.
A1 - Zhao, H.
A1 - Vogel, F.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
A1 - Raabe, D.
A1 - Gault, B.
T1 - Revealing in-plane grain boundary composition features through machine learning from atom probe tomography data
N2 - Grain boundaries (GBs) are planar lattice defects that govern the properties of many types of polycrystalline materials. Hence, their structures have been investigated in great detail. However, much less is known about their chemical features, owing to the experimental difficulties to probe these features at the atomic length scale inside bulk material specimens. Atom probe tomography (APT) is a tool capable of accomplishing this task, with an ability to quantify chemical characteristics at near-atomic scale. Using APT data sets, we present here a machine-learning-based approach for the automated quantification of chemical features of GBs. We trained a convolutional neural network (CNN) using twenty thousand synthesized images of grain interiors, GBs, or triple junctions. Such a trained CNN automatically detects the locations of GBs from APT data. Those GBs are then subjected to compositional mapping and analysis, including revealing their in-plane chemical decoration patterns. We applied this approach to experimentally obtained APT data sets pertaining to three case studies, namely, Ni-P, Pt-Au, and Al-Zn-Mg-Cu alloys. In the first case, we extracted GB specific segregation features as a function of misorientation and coincidence site lattice character. Secondly, we revealed interfacial excesses and in-plane chemical features that could not have been found by standard compositional analyses. Lastly, we tracked the temporal evolution of chemical decoration from early-stage solute GB segregation in the dilute limit to interfacial phase separation, characterized by the evolution of complex composition patterns. This machine-learning-based approach provides quantitative, unbiased, and automated access to GB chemical analyses, serving as an enabling tool for new discoveries related to interface thermodynamics, kinetics, and the associated chemistry-structure-property relations.
KW - Machine learning
KW - Digitalization
KW - Alloy microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543049
DO - https://doi.org/10.1016/j.actamat.2022.117633
SN - 1359-6454
VL - 226
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Darvishi Kamachali, Reza
T1 - On the origin of embrittlement in Mn containing and Zn-coated steels
N2 - Grain boundary embrittlement in medium-Mn steels and liquid metal embrittlement (LME) in Zn-coated high strength steels are among key challenges on the way of safe application of sustainable steels for automotive industry. Using a novel density-based model for grain boundaries, we reveal that the affinity of a grain boundary to attract Mn and Zn atoms result in a segregation transition accompanied by interfacial structural changes. In case of the Zn, the simulations show that the amount of segregation abruptly increases with decreasing temperature, while the Zn content in the alloy, required for triggering the segregation transition, decreases. The results are discussed in the context of CALPHAD-integrated density-based grain boundary phase diagrams.
T2 - DPG 2024
CY - Berlin, Germany
DA - 17.03.2024
KW - Phase-Field Simulation
KW - CALPHAD
KW - Steels
KW - Density-based Thermodynamics
PY - 2024
AN - OPUS4-60743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, L.
A1 - Darvishi Kamachali, Reza
A1 - Li, Z.
A1 - Zhang, Z.
T1 - Grain boundary energy effect on grain boundary segregation in an equiatomic high-entropy alloy
N2 - Grain boundary (GB) Segregation has a substantial effect on the microstructure evolution and properties of polycrystalline alloys. The mechanism of nanoscale segregation at the various GBs in multicomponent alloys is of great challenge to reveal and remains elusive so far. To address this issue, we studied the GB segregation in a representative equiatomic FeMnNiCoCr high-entropy alloy (HEA) aged at 450 °C. By combining transmission Kikuchi diffraction, atom probe tomography analysis and a density-based thermodynamics modeling, we uncover the nanoscale segregation behavior at a series of well-characterized GBs of different characters. No segregation occurs at coherent twin boundaries; only slight nanoscale segregation of Ni takes place at the low-angle GBs and vicinal \Sigma 29b coincidence site lattice GBs. Ni and Mn show cosegregation of high levels at the general high-angle GBs with a strong depletion in Fe, Cr, and Co. Our density-based thermodynamic model reveals that the highly negative energy of mixing Ni and Mn is the main driving force for nanoscale cosegregation to the GBs. This is further assisted by the opposite segregation of Ni and Cr atoms with a positive enthalpy of mixing. It is also found that GBs of higher interfacial energy, possessing lower atomic densities (higher disorder and free volume), show higher segregation levels. By clarifying the origins of GB segregations in the FeMnNiCoCr HEA, the current work provides fundamental ideas on nanoscale segregation at crystal defects in multicomponent alloys.
KW - Thermodynamics
KW - High-Entropy Alloys
KW - Grain Boundary Segregation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508827
DO - https://doi.org/10.1103/PhysRevMaterials.4.053603
VL - 4
IS - 5
SP - 053603
PB - American Physical Society
AN - OPUS4-50882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindrachuk, Vitaliy
A1 - Darvishi Kamachali, Reza
T1 - Mean-field modeling and phase-field simulation of grain growth under directional driving forces
N2 - Directional grain growth is a common phenomenon in the synthetic and natural evolution of various polycrystals. It occurs in the presence of an external driving force, such as a temperature gradient, along which grains show a preferred, yet competitive, growth. Novel additive manufacturing processes, with intense, localized energy deposition, are prominent examples of when directional grain growth can occur, beneath the melting pool. In this work, we derive a phenomenological mean-field model and perform 3D phase-field simulations to investigate the directional grain growth and its underlying physical mechanisms. The effect of the intensity of driving force is simulated and systematically analyzed at the evolving growth front as well as various cross-sections perpendicular to the direction of the driving force. We found that although the directional growth significantly deviates from normal grain growth, it is still governed by a power law relation α tⁿ with an exponent n ~ 0.6–0.7. The exponent n exhibits a nontrivial dependence on the magnitude of the directional driving force, such that the lowest growth exponent is observed for intermediate driving forces. We elaborate that this can originate from the fact that the forces at grain boundary junctions evolve out of balance under the influence of the directional driving force. With increasing the driving forces, the growth exponent asymptotically approaches a value of n ≈ 0.63, imposed by the largest possible grain aspect ratio for given grain boundary energies. The current combined mean-field and phase-field framework pave the way for future exploration in broader contexts such as the evolution of complex additively manufactured microstructures.
KW - Additive manufacturing
KW - Phase-field simulation
KW - Grain growth
KW - Mean-field modelling
KW - Directional grain growth
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593210
DO - https://doi.org/10.1016/j.mtla.2023.101989
SN - 2589-1529
VL - 33
SP - 1
EP - 10
PB - Elsevier
AN - OPUS4-59321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Murugan, Jegatheesan
A1 - Darvishi Kamachali, Reza
T1 - High‑throughput investigation of grain boundary segregation landscape in the Fe–Ni–Cr system
N2 - Understanding phase stability in multicomponent alloy systems, particularly at internal interfaces, remains a major challenge in materials science. Grain boundary (co-)segregation is a critical factor influencing interfacial stability, often leading to microstructural degradation and safety concerns. In this study, we investigate segregation behavior in the face-centered cubic (FCC) Fe–Ni–Cr alloy system, a foundational system for many steels, superalloys, and high-entropy alloys. CALPHAD-integrated density-based phase-field model is extended to compute the segregation of Fe, Ni, and Cr at grain boundaries as a function of the bulk composition, with the relative GB density serving as a key parameter representing grain boundary character. A high-throughput computational screening is performed across the stable compositional space at 723 K, 1023 K, and 1323 K. The results reveal a rich and temperature-sensitive segregation landscape, with element-specific enrichment and depletion patterns that vary with alloy composition. Notably, opposite segregation trends between Ni and Cr, and frequent co-segregation of Fe and Ni, are observed at lower temperatures. The developed framework captures the coupled effects of temperature, chemical interactions, grain boundary structure, and enthalpy-entropy compensation on segregation and GB phase stability. The origin and implications of these phenomena are discussed in terms of the underlying thermodynamic driving forces.
KW - Segregation Engineering
KW - Grain boundary segregation
KW - Thermodynamics
KW - CALPHAD
KW - Fe--Ni--Cr alloys
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646404
DO - https://doi.org/10.1007/s10853-025-11717-5
SN - 1573-4803
SP - 1
EP - 21
PB - Springer Science + Business Media
CY - Dordrecht [u.a.]
AN - OPUS4-64640
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kianinejad, Kaveh
A1 - Fedelich, Bernard
A1 - Darvishi Kamachali, Reza
A1 - Schriever, Sina
A1 - Manzoni, Anna Maria
A1 - Agudo Jácome, Leonardo
A1 - Megahed, Sandra
A1 - Kamrani, Sepideh
A1 - Saliwan Neumann, Romeo
T1 - Experimentally informed multiscale creep modelling of additive manufactured Ni-based superalloys
N2 - Excellent creep resistance at elevated temperatures, i.e. T / T_m> 0.5, due to γ-γ’ microstructure is one of the main properties of nickel-based superalloys. Due to its great importance for industrial applications, a remarkable amount of research has been devoted to understanding the underlying deformation mechanism in a wide spectrum of temperature and loading conditions. Additive manufactured (AM) nickel-based superalloys while being governed by similar γ-γ’ microstructure, exhibit AM-process specific microstructural characteristics, such as columnar grains, strong crystallographic texture (typically <001> fiber texture parallel to build direction) and compositional inhomogeneity, which in turn leads to anisotropic creep response in both stationary and tertiary phases.
Despite the deep insights achieved recently on the correlation between process parameters and the resulting microstructure, the anisotropic creep behavior and corresponding deformation mechanism of these materials are insufficiently understood so far. One reason for this is the lack of capable material models that can link the microstructure to the mechanical behavior. To overcome this challenge, a multiscale microstructure-based approach has been applied by coupling crystal plasticity (CP) and polycrystal model which enables the inclusion of different deformation mechanisms and microstructural characteristics such as crystallographic texture and grain morphology. The method has been applied to experimental data for AM-manufactured INCONEL-738LC (IN738). The effect of different slip systems, texture, and morphology on creep anisotropy at 850°C has been investigated. Results suggest a strong correlation between superlattice extrinsic stacking fault (SESF) and microtwinning and observed creep anisotropy.
T2 - EUROMAT 23
CY - Frankfurt a. M., Germany
DA - 04.09.2023
KW - IN738LC
KW - Creep anisotropy
KW - Crystal plasticity
PY - 2023
AN - OPUS4-58263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feldmann, Titus
A1 - Fedelich, Bernard
A1 - Epishin, A.
T1 - Simulation of Hot Isostatic Pressing in a Single-Crystal Ni Base Superalloy with the Theory of Continuously Distributed Dislocations Combined with Vacancy Diffusion
N2 - Single-crystal components made of nickel base superalloys contain pores after casting and homogenization heat treatment. Hot isostatic pressing (HIP), which is carried above the γ' -solvus temperature of the alloy, is industrially applied to reduce porosity. A modeling of HIP based on continuously distributed dislocations is developed in a 2D setting. Glide and climb of straight-edge dislocations, as well as vacancy diffusion, are the deformation mechanisms taken into account.
Thereby, dislocation glide is controlled by dragging a cloud of large atoms, and climb is controlled by vacancy diffusion. Relying on previous investigations of the creep behavior at HIP temperatures, it is assumed that new dislocations are nucleated at low-angle boundaries (LAB) and move through subgrains until they either reach the opposite LABs or react with other dislocations and annihilate.
Vacancies are created at the pore surface and diffuse through the alloy until they are either consumed by climbing dislocations or disappear at the LABs. The field equations are solved by finite elements. It is shown that pore shrinking is mostly controlled by vacancy diffusion as the shear stresses at the LABs are too low to
nucleate a sufficient amount of dislocations.
KW - Nickel-base superalloys
KW - HIP
KW - Dislocation
KW - Creep
KW - Model
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542309
DO - https://doi.org/10.1002/adem.202101341
VL - 2022
PB - Wiley
AN - OPUS4-54230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
A1 - da Silva, A.
A1 - McEniry, E.
A1 - Gault, B.
A1 - Neugebauer, J.
A1 - Raabe, D.
T1 - Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries
N2 - Segregation to grain boundaries affects their cohesion, corrosion, and embrittlement and plays a critical role in heterogeneous nucleation. In order to quantitatively study segregation and low-dimensional phase separation at grain boundaries, here, we apply a density-based phase-field model. The current model describes the grain-boundary thermodynamic properties based on available bulk thermodynamic data, while the grain-boundary-density profile is obtained using atomistic simulations. To benchmark the performance of the model, Mn grain-boundary segregation in the Fe–Mn system is studied. 3D simulation results are compared against atom probe tomography measurements conducted for three alloy compositions. We show that a continuous increase in the alloy composition results in a discontinuous jump in the segregation isotherm. The jump corresponds to a spinodal Phase separation at grain boundary. For alloy compositions above the jump, we reveal an interfacial transient spinodal phase separation.
The transient spinodal phenomenon opens opportunities for knowledge-based microstructure design through the chemical manipulation of grain boundaries. The proposed density-based model provides a powerful tool to study thermodynamics and kinetics of segregation and phase changes at grain boundaries.
KW - Grain Boundary Spinodal
KW - Densty-based Thermodynamics
KW - Microstrucrue Design
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519497
DO - https://doi.org/10.1038/s41524-020-00456-7
VL - 6
IS - 1
SP - 191
PB - Nature
AN - OPUS4-51949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Lei
A1 - Darvishi Kamachali, Reza
T1 - Density-based grain boundary phase diagrams: Application to Fe-Mn-Cr, Fe-Mn-Ni, Fe-Mn-Co, Fe-Cr-Ni and Fe-Cr-Co alloy systems
N2 - Phase diagrams are the roadmaps for designing bulk phases. Similar to bulk, grain boundaries can possess various phases, but their phase diagrams remain largely unknown. Using a recently introduced density-based model, here we devise a strategy for computing multi-component grain boundary phase diagrams based on available bulk (CALPHAD) thermodynamic data. Fe-Mn-Cr, Fe-Mn-Ni, Fe-Mn-Co, Fe-Cr-Ni and Fe-Cr-Co alloy systems, as important ternary bases for several trending steels and high-entropy alloys, are studied. We found that despite its solute segregation enrichment, a grain boundary can have lower solubility limit than its corresponding bulk, promoting an interfacial chemical decomposition upon solute segregation. This is revealed here for the Fe-Mn-base alloy systems. The origins of this counter-intuitive feature are traced back to two effects, i.e., the magnetic ordering effect and the low cohesive energy of Mn solute element. Different aspects of interfacial phase stability and GB co-segregation in ternary alloys are investigated as well. We show that the concentration gradient energy contributions reduce segregation level but increase grain boundary solubility limit, stabilizing the GB against a chemical decomposition. Density-based grain boundary phase diagrams offer guidelines for systematic investigation of interfacial phase changes with applications to microstructure defects engineering.
KW - Densty-based Thermodynamics
KW - Microstrucrue Design
KW - Grain Boundary Phase Diagram
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522207
DO - https://doi.org/10.1016/j.actamat.2021.116668
SN - 1359-6454
VL - 207
SP - 116668
PB - Elsevier Ltd.
AN - OPUS4-52220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jacobson, D.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
T1 - Extending Density Phase-Field Simulations to Dynamic Regimes
N2 - Density-based phase-field (DPF) methods have emerged as a technique for simulating grain boundary thermodynamics and kinetics. Compared to the classical phase-field, DPF gives a more physical description of the grain boundary structure and chemistry, bridging CALPHAD databases and atomistic simulations, with broad applications to grain boundary and segregation engineering. Notwithstanding their notable progress, further advancements are still warranted in DPF methods. Chief among these are the requirements to resolve its performance constraints associated with solving fourth-order partial differential equations (PDEs) and to enable the DPF methods for simulating moving grain boundaries. Presented in this work is a means by which the aforementioned problems are addressed by expressing the density field of a DPF simulation in terms of a traditional order parameter field. A generic DPF free energy functional is derived and used to carry out a series of equilibrium and dynamic simulations of grain boundaries in order to generate trends such as grain boundary width vs. gradient energy coefficient, grain boundary velocity vs. applied driving force, and spherical grain radius vs. time. These trends are compared with analytical solutions and the behavior of physical grain boundaries in order to ascertain the validity of the coupled DPF model. All tested quantities were found to agree with established theories of grain boundary behavior. In addition, the resulting simulations allow for DPF simulations to be carried out by existing phase-field solvers.
KW - CALPHAD
KW - Phase-field modelling
KW - Phase-Field Simulations
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581365
DO - https://doi.org/10.3390/met13081497
VL - 13
SP - 1
EP - 16
AN - OPUS4-58136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezhov, Alexander
A1 - Kulisch, D.
A1 - Goncharov, A.
A1 - Zhutovsky, S.
T1 - A Comparative Study of Factors Influencing Hydration Stoppage of Hardened Cement Paste
N2 - There is no consensus on which hydration stoppage method is optimal to preserve the microstructure and mineral composition of samples, especially considering the specific aspects of different testing methods, such as TGA, MIP, or XRD. This paper presents a quantitative comparison between the most popular hydration stoppage strategies and parameters such as the sample piece size, the soaking time in a solvent, and the type, as examined on cement paste hydrated for 7 days. It was found that the carbonation appears either for samples smaller than 2.36 mm and bigger than 4.75 mm or samples soaked in a solvent for longer than 1 h. Fast solvent replacement leads to ettringite diminution and total pore volume increase. Among others, solvent replacement with subsequent gentle heating under a vacuum was found to be the most efficient, whereas it was experimentally demonstrated that isopropyl alcohol stops hydration faster than ethanol and acetone.
KW - Hydration stoppage
KW - Solvent replacement
KW - Soaking time
KW - Sample piece size
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582430
DO - https://doi.org/10.3390/su15021080
VL - 15
IS - 2
SP - 1
EP - 21
PB - MDPI
CY - Basel, Switzerland.
AN - OPUS4-58243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Breidung, Marc
A1 - Wossidlo, Peter
A1 - Wahl, Ken
A1 - Gerwien, Peter
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Küppers, M.
ED - Zimmermann, Martina
T1 - Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels
N2 - Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt werden, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Kerbschlagarbeit
KW - Achsschenkel
KW - Fail-safe
KW - Bruchmechanische Auslegung
KW - Korrelation
PY - 2022
SP - 1
EP - 6
PB - DGM - Deutsche Gesellschaft für Materialkunde e.V.
CY - Sankt Augustin
AN - OPUS4-56152
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holzwarth, M.
A1 - Baer, Wolfram
A1 - Mayer, U.
A1 - Weihe, S.
T1 - Untersuchung des Master Curve-Konzepts für ferritisches Gusseisen mit Kugelgraphit
N2 - Das Master Curve (MC) Konzept nach ASTM E1921 wird momentan u.a. in der Kerntechnik für die bruchmechanische Sicherheitsbewertung ferritischer Stähle eingesetzt.
Für ferritisches Gusseisen mit Kugelgraphit (GJS) fehlt jedoch eine Validierung dieser Methode und ggf. eine systematische Überprüfung möglicher Modifikationen grundlegender Ansätze des MC-Konzepts. Aus diesem Grund soll in einem kürzlich gestarteten BMUV-Verbundprojekt zwischen der MPA Stuttgart und der BAM Berlin die Anwendbarkeit des MC-Konzepts auf GJS bei dynamischer Beanspruchung untersucht werden. Ziel ist es, eine effektive und effiziente Methodik bereitzustellen, mit der mittels einer vergleichsweise kleinen Stichprobe bruchmechanischer Kleinproben eine Referenztemperatur T0 zur werkstoffspezifischen Temperaturjustierung der MC ermittelt werden kann.
T2 - 55. Jahrestagung des DVM-Arbeitskreises "Bruchmechanik und Bauteilsicherheit"
CY - Darmstadt, Germany
DA - 14.02.2023
KW - Dynamische Beanspruchung
KW - Bruchmechanik
KW - Master Curve-Konzept
KW - Gusseisen mit Kugelgraphit
PY - 2023
DO - https://doi.org/10.48447/Br-2023-BB
SP - 101
EP - 108
PB - DVM Berlin
CY - Berlin
AN - OPUS4-57024
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holzwarth, M.
A1 - Baer, Wolfram
T1 - Untersuchung des Master Curve-Konzeptes für ferritisches Gusseisen mit Kugelgraphit
N2 - Das Master Curve (MC) Konzept nach ASTM E1921 wird momentan u.a. in der Kerntechnik für die bruchmechanische Sicherheitsbewertung ferritischer Stähle eingesetzt. Für ferritisches Gusseisen mit Kugelgraphit (GJS) fehlt jedoch eine Validierung dieser Methode und ggf. eine systematische Überprüfung möglicher Modifikationen grundlegender Ansätze des MC-Konzepts. Aus diesem Grund soll in einem kürzlich gestarteten BMUV-Verbundprojekt zwischen der MPA Stuttgart und der BAM Berlin die Anwendbarkeit des MC-Konzepts auf GJS bei dynamischer Beanspruchung untersucht werden. Ziel ist es, eine effektive und effiziente Methodik bereitzustellen, mit der mittels einer vergleichsweise kleinen Stichprobe bruchmechanischer Kleinproben eine Referenztemperatur T0 zur werkstoffspezifischen Temperaturjustierung der MC ermittelt werden kann.
T2 - 55. Jahrestagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Darmstadt, Germany
DA - 14.02.2023
KW - Bruchmechanik
KW - Master Curve-Konzept
KW - Dynamische Beanspruchung
KW - Gusseisen mit Kugelgraphit
PY - 2023
AN - OPUS4-57025
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
ED - Zimmermann, M.
T1 - Zur Frage der Verwendung von Untermaßprobenergebnissen des Kerbschlagbiegeversuchs - Eine ernüchternde Bilanz
N2 - Der Kerbschlagbiegeversuch ist seit der ersten Hälfte des letzten Jahrhunderts standardisiert und seit langem als Prüfverfahren international genormt. Weltweit sind zu garantierende Werte der Kerbschlagenergie (KV) und Übergangstemperaturen (TÜ) in Produktnormen und Regelwerken festgelegt. Unter bestimmten Bedingungen besteht dabei die Option, statt Normalproben Untermaßproben zu prüfen. Im Rahmen einer Untersuchung der BAM wurde der aktuelle Status von Prüf- und Produktnormen sowie Regelwerken zur Bewertung der Bauteilintegrität hinsichtlich ihres Umgangs mit Untermaßprobenergebnissen erfasst. Zur Schaffung einer geeigneten aktuellen Datenbasis wurden an ISO-V-Proben der Dicken 2,5, 5,0, 7,5 und 10,0 mm aus vier aktuellen Baustählen KV2-T-Kurven ermittelt. Es wurden unterschiedliche Vorgehensweisen zur Kurvenanpassung und Festlegung von Übergangstemperaturen praktiziert. Ferner kamen verfügbare Ansätze zur Skalierung von Untermaßprobenergebnissen auf die Werte von Normalproben zur Anwendung. Das Ausmaß des Probendickeneffektes ist werkstoff- und temperaturabhängig. Im Bereich der Werkstoffprüfung ist akzeptiert, dass die Ergebnisse von Normal- und Untermaß-proben nicht ohne Weiteres ineinander überführt werden können. Der Stand der Produktnormung und der Regelwerke ist jedoch im besten Falle als unzureichend, vielfach jedoch schlicht als falsch zu bezeichnen. In einem weiten anwendungsrelevanten Temperaturbereich werden hier sogar deutlich nicht-konservative Skalierungsergebnisse geliefert. Die betroffenen Produkt-normenreihen und Regelwerke müssen überarbeitet werden.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022: Werkstoffe und Bauteile auf dem Prüfstand, Prüftechnik – Kennwertermittlung – Schadensvermeidung
CY - Dresden, Germany
DA - 27.10.2022
KW - Kerbschlagbiegeversuch, Untermaßproben, Normalproben, Skalierung von Ergebnissen
PY - 2022
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Materialkunde (DGM)
CY - Sankt Augustin
AN - OPUS4-56155
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Zur Frage der Verwendung von Untermaßprobenergebnissen des Kerbschlagbiegeversuchs – eine ernüchternde Bilanz
N2 - Der Kerbschlagbiegeversuch ist seit der ersten Hälfte des letzten Jahrhunderts standardisiert und seit langem als Prüfverfahren international genormt. Weltweit sind zu garantierende Werte der Kerbschlagenergie (KV) und Übergangstemperaturen (TÜ) in Produktnormen und Regelwerken festgelegt. Unter bestimmten Bedingungen besteht dabei die Option, statt Normalproben Untermaßproben zu prüfen. Im Rahmen einer Untersuchung der BAM wurde der aktuelle Status von Prüf- und Produktnormen sowie Regelwerken zur Bewertung der Bauteilintegrität hinsichtlich ihres Umgangs mit Untermaßprobenergebnissen erfasst. Zur Schaffung einer geeigneten aktuellen Datenbasis wurden an ISO-V-Proben der Dicken 2,5, 5,0, 7,5 und 10,0 mm aus vier aktuellen Baustählen KV2-T-Kurven ermittelt. Es wurden unterschiedliche Vorgehensweisen zur Kurvenanpassung und Festlegung von Übergangstemperaturen praktiziert. Ferner kamen verfügbare Ansätze zur Skalierung von Untermaßprobenergebnissen auf die Werte von Normalproben zur Anwendung. Das Ausmaß des Probendickeneffektes ist werkstoff- und temperaturabhängig. Im Bereich der Werkstoffprüfung ist akzeptiert, dass die Ergebnisse von Normal- und Untermaß-proben nicht ohne Weiteres ineinander überführt werden können. Der Stand der Produktnormung und der Regelwerke ist jedoch im besten Falle als unzureichend, vielfach jedoch schlicht als falsch zu bezeichnen. In einem weiten anwendungsrelevanten Temperaturbereich werden hier sogar deutlich nicht-konservative Skalierungsergebnisse geliefert. Die betroffenen Produkt-normenreihen und Regelwerke müssen überarbeitet werden.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Skalierung von Ergebnissen
KW - Kerbschlagbiegeversuch
KW - Untermaßproben
KW - Normalproben
PY - 2022
AN - OPUS4-56156
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallin, Kim
A1 - Baer, Wolfram
T1 - Evaluation of Charpy-V transition curve fitting based on distribution-free statistical assessment
N2 - A non-parametric, distribution-free, statistical assessment of 5 large Charpy transition curve data sets is used for the optimum fitting equations for smaller data sets. The assessment makes use of a combination of rank probability and binomial probability analysis of the data. The original non-parametric assessment method is improved by combining upper and lower bound binomial estimates, thus removing a bias that exists in the original method. The non-parametric assessment is not suitable as a standard method because it requires too many data points to give a reliable result. It is, however, ideal as a research tool to examine transition curve shape and scatter. Based on the assessment several recommendations for transition curve fitting can be made.
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
KW - Charpy Impact Test
KW - Charpy Transition Curve
PY - 2023
DO - https://doi.org/10.1016/j.ijpvp.2023.105079
SN - 0308-0161
VL - 206
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-58635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Chunky Graphite - Recognition, Quantification, and Impact on Properties of Spheroidal Graphite Cast Iron
N2 - Since there is a continuously growing demand for complex, frequently heavy-sectioned spheroidal graphite cast iron (SGI) castings it is worth paying attention to the chunky graphite (CHG) degeneration which may occur under certain technological circumstances. Although a reference line for preventive actions in terms of general metallurgical and process measures could be drawn to avoid CHG in heavy-sectioned ferritic SGI castings, a broad majority of experts claim the avoidance of CHG in heavy sections cannot yet be rated a hundred percent process safe. A major reason may be seen in the fact that a universal, generally accepted explanation of CHG formation and growth has not yet been established, although several theories have been proposed. Nevertheless, metallurgical aspects are not in the focus of this paper.
This paper is about the current state of methods to detect CHG in SGI on the laboratory and component scales. Capabilities and limits of different metallographic, fractographic and non-destructive computer tomographic methods to recognize and quantify CHG are discussed. With respect to the characteristic fili-gree three-dimensional string-like, multi-branched CHG structure, which is non-isometric and non-dispersed, serious implications on the possibility to quantitatively characterize the amount of CHG must be considered.
In contrary to the metallurgical aspects, the knowledge about the impact of CHG on the materials and com-ponents properties is still surprisingly limited. Therefore, special emphasis of this paper is on the impact of CHG degeneration on the properties of ferritic SGI. Experimental results are reviewed to illustrate the effect of CHG on mechanical strength and ductility properties as well as fracture mechanics properties in terms of crack resistance and fracture toughness.
The present situation is characterized by discussions and uncertainty about the acceptance or rejection of SGI components containing CHG. Addressing this, conclusions from the materials engineering point of view are drawn for quality control, a safe operational strategy in the foundry and component safety.
T2 - InCeight Casting 2023
CY - Darmstadt, Germany
DA - 06.03.2023
KW - Chunky graphite
KW - Structure
KW - Recognition
KW - Quantification
KW - Tensile properties
KW - Fracture toughness
KW - Ferritic spheroidal
KW - Graphite cast iron
PY - 2023
AN - OPUS4-57121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Detection and understanding of the chunky graphite degeneration in ferritic spheroidal graphite cast iron materials with respect to fatigue
N2 - CHG is very different compared to other graphite degenerations or defects;
Filigree, multi-branched string-like, 3d interconnected structure;
Morphology and volumetric amount of CHG cannot be accessed by stereological interpretation of 2d section data;
Field-tested, technically established method to quantify CHG in components not available;
Fatigue: CHG causes substantial reduction in fatigue limit and significant increase in crack growth rate;
Therefore: Avoid or exclude CHG!
T2 - 4th International Symposium on Fatigue Design and Material Defects
CY - Online meeting
DA - 26.05.2020
KW - Ductile cast iron
KW - Chunky graphite degeneration
KW - Fatigue
KW - Correlation microstructure to properties
PY - 2020
AN - OPUS4-54409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Holzwarth, M.
A1 - Mayer, U.
T1 - Investigation of the Master Curve Concept for ferritic Ductile Cast Iron
N2 - Based on state-of-the-art research and regulations, the application of the fracture mechanics master curve (MC) concept to ferritic ductile cast iron (DCI) is being investigated in a recently started German joint research project between BAM Berlin and MPA Stuttgart. This paper outlines the research approach and the planned investigations and provides first results.
According to the IAEA guidelines SSG 26, the safety assessment of DCI containers for transport as well as interim and final storage of radioactive materials is based on the fracture mechanics criterion of general crack initiation exclusion. Within this context, the focus of the current research project is on the further development of brittle fracture safety assessment methods under dynamic loading conditions. Within fracture mechanics safety assessments for steels in nuclear technology, the probabilistic MC concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. The MC concept allows for an effective statistical consideration of the scatter of the material toughness in the transition regime. Furthermore, the MC can also be used for elevated loading rates as they occur in accident or crash scenarios. However, for DCI, a systematic review of potential modifications to the MC assumptions and procedure according to ASTM E1921 and an associated validation are still lacking. Therefore, a corresponding methodology shall be established to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using samples extracted from a component.
For the experimental program, a DCI material was produced as it is generally used for transport and storage containers. A basic mechanical-technological material characterization consisting of tensile, Charpy, and Pellini tests is planned. A comprehensive fracture mechanics test program was compiled covering dynamic testing of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25, and SE(B)140 specimens. Moreover, numerical analyses of different specimen geometries and test setups are planned to investigate the influences of stress triaxiality and loading rate. Throughout the experimental program, the microstructure-property relationship will be investigated based on quantitative metallographic and fractographic analyses. Finally, different MC assessment strategies will be considered, and modifications will be made if necessary.
T2 - PATRAM22 Conference
CY - Juans-les-Pins, France
DA - 11.06.2023
KW - Master Curve
KW - Ductile cast iron
KW - Dynamic fracture toughness
PY - 2023
SP - 1
EP - 9
PB - World Nuclear Transport Institute
AN - OPUS4-57765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
ED - Bleicher, C.
ED - Kaufmann, H.
ED - Pittel, C.
T1 - Chunky Graphite - Recognition, Quantification, and Impact on Properties of Spheroidal Graphite Cast Iron
N2 - Since there is a continuously growing demand for complex, frequently heavy-sectioned spheroidal graphite cast iron (SGI) castings it is worth paying attention to the chunky graphite (CHG) degeneration which may occur under certain technological circumstances. Although a reference line for preventive actions in terms of general metallurgical and process measures could be drawn to avoid CHG in heavy-sectioned ferritic SGI castings, a broad majority of experts claim the avoidance of CHG in heavy sections cannot yet be rated a hundred percent process safe. A major reason may be seen in the fact that a universal, generally accepted explanation of CHG formation and growth has not yet been established, although several theories have been proposed. Nevertheless, metallurgical aspects are not in the focus of this paper.
This paper is about the current state of methods to detect CHG in SGI on the laboratory and component scales. Capabilities and limits of different metallographic, fractographic and non-destructive computer tomographic methods to recognize and quantify CHG are discussed. With respect to the characteristic fili-gree three-dimensional string-like, multi-branched CHG structure, which is non-isometric and non-dispersed, serious implications on the possibility to quantitatively characterize the amount of CHG must be considered.
In contrary to the metallurgical aspects, the knowledge about the impact of CHG on the materials and com-ponents properties is still surprisingly limited. Therefore, special emphasis of this paper is on the impact of CHG degeneration on the properties of ferritic SGI. Experimental results are reviewed to illustrate the effect of CHG on mechanical strength and ductility properties as well as fracture mechanics properties in terms of crack resistance and fracture toughness.
The present situation is characterized by discussions and uncertainty about the acceptance or rejection of SGI components containing CHG. Addressing this, conclusions from the materials engineering point of view are drawn for quality control, a safe operational strategy in the foundry and component safety.
T2 - InCeight Casting Conference 2023
CY - Darmstadt, Germany
DA - 06.03.2023
KW - Fracture toughness
KW - Chunky graphite
KW - Structure
KW - Recognition
KW - Quantification
KW - Ferritic spheroidal graphite cast iron
KW - Tensile properties
PY - 2023
SN - 978-3-8396-1892-9
SP - 1
EP - 11
PB - Fraunhofer Verlag
AN - OPUS4-57120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
A1 - Abbasi, Behboud
T1 - On the question of how to analyze and apply Charpy pendulum impact test results correctly - Shortcomings in corresponding procedures and standards
N2 - This paper is focused on the approximation of absorbed Charpy impact energy-temperature curves (KV-T) and the management of sub-size test piece results in Charpy pendulum impact tests. Both subjects are frequently underestimated but may have a strong impact on the assessment of product quality and structural integrity. The status of related test standards, product standards, structural integrity assessment procedures and corresponding research is reviewed.
It is concluded that the state of regulation is partly insufficient and wrong. There is a wide gap between the state of knowledge in the field of materials testing and the requirements of product standards and structural integrity assessment procedures. The present paper aims at boosting and supporting the necessary discussion among the parties involved to raise the level of technical safety. Correspondingly, a large experimental database was created by Charpy impact testing of popular modern structural Steels with nominal yield strength from 235 MPa to 960 MPa. KV-T data were generated using test pieces with thicknesses between 2.5 mm and 10 mm. Different strategies for KV-T curve fitting, definition of transition temperatures, as well as upper and lower shelf energy levels were followed, and different scaling procedures were applied to the sub-size test piece results. The results show that proportional scaling of sub-size to full-size test piece results in terms of KV should be disallowed because it is a wrong approach.
Regulations still incorporating such procedures should be revised as soon as possible. Existing nonproportional scaling and conversion procedures were applied. The results obtained illustrate that neither an overall nor consistent conservatism nor an adequate conservatism level can be achieved. In summary, the standardizing bodies should enforce the discussion to revise relevant test standards considering more precise specifications on Charpy data fitting. Furthermore, proposals are made for an improved management of sub-size test piece results.
KW - Structural integrity assessment procedure
KW - Charpy pendulum impact test
KW - Sub-size test piece
KW - Standard test piece
KW - Curve fitting
KW - Conversion of results
KW - Absorbed energy
KW - Transition temperature
KW - Steel
KW - Test standard
KW - Product standard
PY - 2022
DO - https://doi.org/10.1520/JTE20210781
SN - 0090-3973
VL - 50
IS - 4
SP - 2268
EP - 2293
PB - American Society for Testing and Materials (ASTM)
CY - West Conshohocken, PA
AN - OPUS4-55172
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meira, Maria Fernanda Cavalcante
A1 - Fernandes, Gabriela Leal Peres
A1 - de Camargo, Andréa Simone Stucchi
A1 - Ravaro, Leandro Piaggi
A1 - Arai, Marylyn Setsuko
A1 - Navarro, Maria Fidela de Lima
A1 - Brighenti, Fernanda Lourenção
A1 - Oliveira, Analú Barros de
A1 - Danelon, Marcelle
ED - Stucchi de Camargo, Andrea
T1 - Modification of restorative glass ionomer cement with zinc oxide nanoparticles and calcium glycerophosphate microparticles: in vitro assessment of mechanical properties and antimicrobial activity
N2 - Abstract The incorporation of bioactive agents into resin-modified glass ionomer cement (RMGIC) is a promising strategy to improve its mechanical strength and biofilm control, especially for patients with active dental caries. Objective This study aimed to evaluate the effects of incorporating ZnONPs and CaGP into RMGIC on its mechanical and microbiological properties. Design Six groups were tested: 1) RMGIC (without CaGP/ZnONPs); 2) RMGIC-1.0%ZnONPs; 3) RMGIC-2.0%ZnONPs; 4) RMGIC-3.0%CaGP; 5) RMGIC-3.0%CaGP-1.0%ZnONPs; and 6) RMGIC-3.0%CaGP-2.0%ZnONPs. The compressive strength (CS), diametral tensile strength (DTS), and surface hardness (SH) were evaluated after 24 hours and 7 days. Antimicrobial and antibiofilm activity were evaluated using agar diffusion and biofilm metabolic activity (XTT) assays. Results After 24 hours, all the groups showed similar DTS values (p0.05), except for RMGIC-3.0%CaGP-1.0%ZnONPs, which showed the highest DTS value (p<0.05). Comparing 24 hours and 7 days, the DTS values of RMGIC-3.0%CaGP-2.0%ZnONPs, RMGIC-3.0%CaGP, and RMGIC-3.0%CaGP-2.0%ZnONPs were similar (p=0.360). After 24 hours, the RMGIC group showed the CS highest value, followed by RMGIC-2.0%ZnONPs (p < 0.05). After 7 days, the RMGIC-3.0%CaGP-1.0%ZnONPs group exhibited the highest CS value, approximately 15% higher than RMGIC (p<0.05). The RMGIC-1.0%ZnONPs group exhibited significantly higher SH at 24 hours (p=0.621). At 7 days, the highest SH value was observed for the RMGIC-3.0%CaGP-1.0%ZnONPs group (p<0.05). Regarding antimicrobial and antibiofilm activity, including results from biofilm metabolism assays, the RMGIC-3.0%CaGP-1.0%ZnONPs group demonstrated the most effective antimicrobial and inhibitory effects (p<0.05). Conclusion This study demonstrated that adding ZnONPs and CaGP to RMGIC enhanced its mechanical and antimicrobial and antibiofilm properties, suggesting enhanced mechanical performance and improved protection against cariogenic biofilms—critical factors for successful restorative treatments. Therefore, the addition of ZnONPs and CaGP is a promising strategy to develop advanced restorative materials that improve clinical outcomes, especially for patients with active dental caries.
KW - Resin-modified glass ionomer cement
KW - Phosphate
KW - Zinc oxide nanoparticles
KW - Biofilm
KW - Mechanical properties
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652799
DO - https://doi.org/10.1590/1678-7757-2025-0356
SN - 1678-7765
VL - 33
SP - 1
EP - 14
PB - FapUNIFESP (SciELO)
AN - OPUS4-65279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn S.
A1 - Brambilla, Gabriel V.
A1 - Corrêa, Bruna Carolina
A1 - Merízio, Leonnam G.
A1 - Inada, Natalia M.
A1 - de Camargo, Andrea S. S.
T1 - A Dual-Mode “Turn-On” Ratiometric Luminescent Sensor Based on Upconverting Nanoparticles for Detection and Differentiation of Gram-Positive and Gram-Negative Bacteria
N2 - Infectious bacterial diseases, intensified by antibiotic resistance, cause millions of deaths annually and pose risks beyond human health, including water and food contamination. Current diagnostics are often slow, require complex equipment, and lack specificity, highlighting the need for rapid and reliable detection methods. To address this, we developed a luminescent sensor based on NaYF4 upconverting nanoparticles (UCNPs) doped with Er3+ or Tm3+, coated with COOH-PEG4-COOH, and functionalized with vancomycin (Van) or polymyxin-B (Poly) to selectively target Gram-positive and Gram-negative bacteria, respectively. Gold nanoparticles (AuNPs) served as quenchers, enabling a ratiometric “turn-on” mechanism: upon bacterial binding, the UCNP emission, initially quenched by AuNPs, was partially restored. This allowed Differentiation through changes in the green/red (G/R) ratio for Er-UCNP@PEG4-Van and the blue/red (B/R) ratio for Tm-UCNP@PEG4-Poly. The sensor distinguished between Gram-positive and Gram-negative bacteria over a wide concentration range (0.05 to 5 × 105 CFU/mL) and showed high correlation with actual bacterial counts (r = 0.99 for S. aureus, r = 0.91 for E. coli). This platform is a potential fast, selective, and reliable tool for bacterial detection in clinical and environmental settings.
KW - Lminescent sensor
KW - Upconverting nanoparticles
KW - Gram-positive and Gram-negative bacteria
KW - Ratiometric luminescent sensors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652785
DO - https://doi.org/10.1021/acsomega.5c07006
SN - 2470-1343
VL - 10
IS - 39
SP - 46040
EP - 46050
PB - American Chemical Society (ACS)
AN - OPUS4-65278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Dietrich, P. M.
A1 - Radnik, Jörg
T1 - In situ monitoring of the influence of water on DNA radiation damage by near-ambient pressure X-ray photoelectron spectroscopy
N2 - Ionizing radiation damage to DNA plays a fundamental role in cancer therapy. X-ray photoelectron-spectroscopy (XPS) allows simultaneous irradiation and damage monitoring. Although water radiolysis is essential for radiation damage, all previous XPS studies were performed in vacuum. Here we present near-ambient-pressure XPS xperiments to directly measure DNA damage under water atmosphere. They permit in-situ monitoring of the effects of radicals on fully hydrated double-stranded DNA. The results allow us to distinguish direct damage, by photons and secondary low-energy electrons (LEE), from damage by hydroxyl radicals or hydration induced modifications of damage pathways. The exposure of dry DNA to x-rays leads to strand-breaks at the sugar-phosphate backbone, while deoxyribose and nucleobases are less affected. In contrast, a strong increase of DNA damage is observed in water, where OH-radicals are produced. In consequence, base damage and base release become predominant, even though the number of strand-breaks increases further.
KW - DNA
KW - XPS
KW - NAP-XPS
KW - Radiation damage
KW - Single-strand break (SSB)
KW - Double-strand break (DSB)
KW - Xray
KW - OH radical
KW - Hydroxyl radical
KW - LEE
KW - Low energy electrons
KW - Dosimetry
KW - Geant4
KW - Geant4-DNA
KW - TOPAS
KW - TOPAS-nbio
KW - Microdosimetry
KW - DNA radiation damage
KW - Direct damage
KW - Indirect damage
KW - Quasi-direct damage
KW - Hydration shell
KW - Dry DNA
KW - Hydrated DNA
KW - ROS
KW - Radical
KW - Reactive oxygen species
KW - Net-ionization reaction
KW - Radiation therapy
KW - Cancer therapy
KW - Xray photo electron spectrocopy
KW - Near ambient pressure xray photo electron spectroscopy
KW - Base damage
KW - Base loss
KW - Dissociative electron transfer (DET)
KW - Dissociative electron attachment (DEA)
KW - Hydrated electron
KW - Prehydrated electron
KW - Ionization
KW - PES
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524060
DO - https://doi.org/10.1038/s42004-021-00487-1
SN - 2399-3669
VL - 4
IS - 1
SP - 50
PB - Springer Nature
CY - London
AN - OPUS4-52406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohammadifar, E.
A1 - Ahmadi, V.
A1 - Gholami, M.F.
A1 - Oehrl, A.
A1 - Kolyvushko, O.
A1 - Nie, C.
A1 - Donskyi, Ievgen
A1 - Herziger, S.
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Böttcher, C.
A1 - Rabe, J.P.
A1 - Osterrieder, K.
A1 - Azab, W.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Graphene-Assisted Synthesis of 2D Polyglycerols as Innovative Platforms for Multivalent Virus Interactions
N2 - 2D nanomaterials have garnered widespread attention in biomedicine and
bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively.
A single-layer hyperbranched polyglycerol containing azide functional
groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes Simplex
virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus Inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.2D nanomaterials have garnered widespread attention in biomedicine and bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively.
A single-layer hyperbranched polyglycerol containing azide functional groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes Simplex virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus Inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.
KW - 2D Materials
KW - Graphene template
KW - Multivalency
KW - Polyglycerol
KW - Virus inhibition
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527726
DO - https://doi.org/10.1002/adfm.202009003
VL - 31
IS - 32
SP - 2009003
PB - Wiley VCH
AN - OPUS4-52772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jungnickel, R.
A1 - Mirabella, Francesca
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Balasubramanian, K.
T1 - Graphene‑on‑gold surface plasmon resonance sensors resilient to high‑temperature annealing
N2 - Gold films coated with a graphene sheet are being widely used as sensors for the detection of label-free binding interactions using surface plasmon resonance (SPR). During the preparation of such sensors, it is often essential to subject the sensor chips to a high-temperature treatment in order to ensure a clean graphene surface. However, sensor chips used currently, which often use chromium as an adhesion promoter, cannot be subjected to temperatures above 250 °C, because under such conditions, chromium is found to reorganize and diffuse to the surface, where it is easily oxidized, impairing the quality of SPR spectra. Here we present an optimized preparation strategy involving a three-cycle tempering coupled with chromium (oxide) etching, which allows the graphene-coated SPR chips to be annealed up to 500 °C with little deterioration of the surface morphology. In addition, the treatment delivers a surface that shows a clear enhancement in spectral response together with a good refractive index sensitivity. We demonstrate the applicability of our sensors by studying the kinetics of avidin–biotin binding at different pH repeatedly on the same chip. The possibility to anneal can be exploited to recover the original surface after sensing trials, which allowed us to reuse the sensor for at least six cycles of biomolecule adsorption.
KW - Surface plasmon resonance
KW - Graphene
KW - Sensing
KW - Surface regeneration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564585
DO - https://doi.org/10.1007/s00216-022-04450-4
SN - 1618-2642
SP - 1
EP - 7
PB - Springer
AN - OPUS4-56458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nickl, Philip
A1 - Hilal, T.
A1 - Olal, D.
A1 - Donskyi, Ievgen
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Haag, R.
T1 - A New Support Film for Cryo Electron Microscopy Protein Structure Analysis Based on Covalently Functionalized Graphene
N2 - Protein adsorption at the air–water interface is a serious problem in cryogenic electron microscopy (cryoEM) as it restricts particle orientations in the vitrified ice-film and promotes protein denaturation. To address this issue, the preparation of a graphene-based modified support film for coverage of conventional holey carbon transmission electron microscopy (TEM) grids is presented. The chemical modification of graphene sheets enables the universal covalent anchoring of unmodified proteins via inherent surface-exposed lysine or cysteine residues in a one-step reaction. Langmuir–Blodgett (LB) trough approach is applied for deposition of functionalized graphene sheets onto commercially available holey carbon TEM grids. The application of the modified TEM grids in single particle analysis (SPA) shows high protein binding to the surface of the graphene-based support film. Suitability for high resolution structure determination is confirmed by SPA of apoferritin. Prevention of protein denaturation at the air–water interface and improvement of particle orientations is shown using human 20S proteasome, demonstrating the potential of the support film for structural biology.
KW - Functionalized graphene
KW - Transmission electron microsocpy
KW - Protein structure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566443
DO - https://doi.org/10.1002/smll.202205932
SN - 1613-6810
SP - 2205932
PB - Wiley VCH
AN - OPUS4-56644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rua-Ibarz, Ana
A1 - Nakadi, Flávio V.
A1 - Bolea-Fernandez, Eduardo
A1 - Bazo, Antonio
A1 - Battistella, Beatrice
A1 - Matiushkina, Anna
A1 - Resch-Genger, Ute
A1 - Abad Andrade, Carlos Enrique
A1 - Resano, Martín
T1 - Discrete entity analysis via microwave-induced nitrogen plasma–mass spectrometry in single-event mode
N2 - In this work, single-event microwave-induced nitrogen plasma–mass spectrometry (single-event MINP-MS) was evaluated for the first time for the analysis of discrete entities such as nanoparticles, biological cells, and microplastics. Nitrogen (N2) effectively overcomes Ar-based polyatomic interferences, enabling (ultra)trace element determination of Fe and Se using their most abundant isotopes, 56Fe (91.66%) and 80Se (49.82%). Iron oxide nanoparticles (Fe2O3 NPs) ranging from 20 to 70 nm were accurately characterized, with excellent agreement with established sizing techniques, such as transmission electron microscopy (TEM) and dynamic light scattering (DLS). A limit of detection (LoD) of 8.6 ag for Fe─equivalent to an LoDsize of 19 nm for Fe2O3─was achieved, which is significantly lower than recent values reported for high-end quadrupole-based ICP-MS. Selenium nanoparticles (SeNPs) of 150 and 250 nm were also accurately characterized, without the N2-based plasma experiencing issues handling relatively large metallic NPs (linearity, R2 = 0.9994). Se-enriched yeast cells (SELM-1 certified reference material) were successfully analyzed via single-cell MINP-MS using external calibration based on SeNPs and a transport efficiency-independent approach. In addition, 2–3 μm polystyrene (PS) and polytetrafluoroethylene (PTFE) were accurately sized by monitoring 12C+, confirming the method’s suitability for handling micrometer-sized polymeric materials (microplastics). The average duration of individual events (680 ± 160 μs) suggests that the digestion of individual entities in N2-based plasmas is comparable to that in Ar-based plasmas. These results open new avenues for this instrumentation as an alternative to ICP ionization sources, also in the context of discrete entity analysis.
KW - Microwave-Induced Nitrogen Plasma
KW - Discrete entity analysis
KW - Particle/droplet event counting
KW - Comparison to SP-ICP-MS methodologies
KW - Nitrogen plasma vs. argon ICP trade-offs
KW - Trace elemental quantification at the single-entity level
KW - Time-resolved mass spectrometry for discrete entities
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643825
DO - https://doi.org/10.1021/acs.analchem.5c04341
SN - 0003-2700
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-64382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marschall, Niklas
A1 - Murugan, Jegatheesan
A1 - Darvishi Kamachali, Reza
T1 - Incorporating elasticity into the thermodynamics and phase diagrams of multi-component systems
N2 - Elastic energy plays a critical role in determining phase stability in compositionally complex alloys. However, quantifying elastic contributions in multi-component systems and incorporating them into phase diagram construction remain challenging. In this study, we present a generalized elastic energy formalism tailored for multi-component alloys, which can be directly and efficiently integrated with CALPHAD thermodynamic databases and existing frameworks such as Thermo-Calc (Andersson et al., 2002), Pandat (Cao et al., 2009) or FactSage (Bale et al., 2016). This elasticity formalism can also be introduced as a post-processing layer in open-source software such as pyCALPHAD (Otis and Liu, 2017) and Kawin (Ury et al., 2023) , enabling elastic assessments in multi-component systems. We apply our framework for constructing the phase diagram of quinary Fe–Mn–Ni–Co–Cu alloy system, utilizing convex hull and Hessian matrix under elastic considerations. Our results reveal that incorporating elastic energy leads to an expansion of both the spinodal region and the miscibility gap. These are governed by the intricate interplay of chemical and elastic driving forces: We found that Mn and Ni contribute strongly to chemical stabilization, while Cu and Co tend to destabilize the alloy, especially at low Mn concentrations. The stabilizing effect of Fe is also pronounced in Mn-deficient regions. Acting as a destabilizing factor, the elastic energy is primarily driven by the presence of Mn, underscoring its multifaceted role in thermodynamic stability. In Mn-rich compositions, Cu markedly reduces the elastic energy contribution. Combined with CALPHAD infrastructures, the current framework offers a practical pathway to improve the predictive accuracy of phase stability and transformations in complex multi-component alloys.
KW - Elastic energy
KW - HEA
KW - CALPHAD
KW - Elastic spinodal
KW - Elastic miscibility gap
KW - Elastic phase diagram
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643339
DO - https://doi.org/10.1016/j.mtla.2025.102546
SN - 2589-1529
VL - 44
SP - 1
EP - 18
PB - Elsevier
CY - Amsterdam, Niederlande
AN - OPUS4-64333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Darvishi Kamachali, Reza
A1 - Boyce, B.L.
A1 - Clark, B.G.
A1 - Raabe, D.
A1 - Thompson, G.B.
T1 - Spinodal Decomposition in Nanocrystalline Alloys
N2 - For more than half a century, spinodal decomposition has been a key phenomenon in considering the formation of secondary phases in alloys. The most prominent aspect of the spinodal phenomenon is the lack of an energy barrier on its transformation pathway, offering an alternative to the nucleation and growth mechanism. The classical description of spinodal decomposition often neglects the influence of defects, such as grain boundaries, on the transformation because the innate ability for like-atoms to cluster is assumed to lead the process. Nevertheless, in nanocrystalline alloys, with a high population of grain boundaries with diverse characters, the structurally heterogeneous landscape can greatly influence the chemical decomposition behavior. Combining atom-probe tomography, precession electron diffraction and density-based phase-field simulations, we address how grain boundaries contribute to the temporal evolution of chemical decomposition within the miscibility gap of a Pt-Au nanocrystalline system. We found that grain boundaries can actually have their own miscibility gaps profoundly altering the spinodal decomposition in nanocrystalline alloys. A complex realm of multiple interfacial states, ranging from competitive grain boundary segregation to barrier-free low-dimensional interfacial decomposition, occurs with a dependency upon the grain boundary character.
KW - Density-based Thermodynamics
KW - Nanocrystalline alloys
KW - Spinodal decomposition
KW - Defects engineering
PY - 2021
DO - https://doi.org/10.1016/j.actamat.2021.117054
VL - 215
SP - 117054
PB - Elsevier Ltd.
AN - OPUS4-52918
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels
N2 - Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt wer-den, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind.
T2 - 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Korrelation
KW - Achsschenkel
KW - Fail-safe
KW - Bruchmechanische Auslegung
KW - Kerbschlagarbeit
PY - 2022
AN - OPUS4-56153
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tidblad, Johan
A1 - Moya Núñez, Alice
A1 - de la Fuente, Daniel
A1 - Ebell, Gino
A1 - Flatlandsmo Berglen, Tore
A1 - Grøntoft, Terje
A1 - Hans, Ulrik
A1 - Christodoulakis, Ioannis
A1 - Kajánek, Daniel
A1 - Kreislová, Kateřina
A1 - Kwiatkowski, Lech
A1 - La Torreta, Teresa
A1 - Lutze, Rafał
A1 - Pinar Larrubia, Guadalupe
A1 - Pintus, Valentina
A1 - Prange, Michael
A1 - Spezzano, Pasquale
A1 - Varotsos, Costas
A1 - Verney-Carron, Aurélie
A1 - Vuorio, Tiina
A1 - Yates, Tim
T1 - Corrosion and Soiling in the 21st Century: Insights from ICP Materials and Impact on Cultural Heritage
N2 - This paper reviews results published by the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials) with emphasis on those obtained after the turn of the century. Data from ICP Materials come from two main sources. The first is through exposures of materials and collection of environmental data in a network of atmospheric exposure test sites mainly distributed across Europe. Corrosion of carbon steel has continued to decrease during the period 2000–2020 but corrosion of zinc only up until 2014, and the trend in zinc corrosion is only visible when examining four-year data. Surface recession of limestone as well as soiling of modern glass show no decreasing trend during 2000–2020. The second is through case studies performed at heritage sites across Europe. Risk analysis of corrosion and soiling for twenty-six sites indicate that currently soiling is a more significant maintenance trigger than corrosion. Costs for maintaining heritage sites are substantial and costs attributable to air pollution is estimated from 40% to as much as 80% of the total cost. Future directions of the program are work on effects of particulate matter, improving the scientific basis for the work, and making the monitoring data publicly available.
KW - Corrosion
KW - Atmospheric corrosion
KW - Soiling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644651
DO - https://doi.org/10.3390/cmd6040054
SN - 2624-5558
VL - 6
IS - 4
SP - 1
EP - 25
PB - MDPI AG
AN - OPUS4-64465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn Setsuko
A1 - Machado, Thales Rafael
A1 - da Silva, Beatriz Giacomelli Rodrigues
A1 - Vilela, Raquel Riciati do Couto
A1 - de Camargo, Andrea Simone Stucchi
A1 - Zucolotto, Valtencir
T1 - Biomimetic Upconverting Nanoplatforms for Glioblastoma Bioimaging and Targeted Therapy
N2 - Infectious bacterial diseases, intensified by antibiotic resistance, cause millions of deaths annually and pose risks beyond human health, including water and food contamination. Current diagnostics are often slow, require complex equipment, and lack specificity, highlighting the need for rapid and reliable detection methods. To address this, we developed a luminescent sensor based on NaYF4 upconverting nanoparticles (UCNPs) doped with Er3+ or Tm3+, coated with COOH-PEG4-COOH, and functionalized with vancomycin (Van) or polymyxin-B (Poly) to selectively target Gram-positive and Gram-negative bacteria, respectively. Gold nanoparticles (AuNPs) served as quenchers, enabling a ratiometric “turn-on” mechanism: upon bacterial binding, the UCNP emission, initially quenched by AuNPs, was partially restored. This allowed differentiation through changes in the green/red (G/R) ratio for Er-UCNP@PEG4-Van and the blue/red (B/R) ratio for Tm-UCNP@PEG4-Poly. The sensor distinguished between Gram-positive and Gram-negative bacteria over a wide concentration range (0.05 to 5 × 105 CFU/mL) and showed high correlation with actual bacterial counts (r = 0.99 for S. aureus, r = 0.91 for E. coli). This platform is a potential fast, selective, and reliable tool for bacterial detection in clinical and environmental settings.
KW - Glioblastoma
KW - Homotypic targeting
KW - Cell membrane coating
KW - Upconverting nanoparticles
KW - Temozolamide
KW - Near infrared bioimaging
KW - Drug delivery
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652808
DO - https://doi.org/10.1021/acsanm.5c04567
SN - 2574-0970
VL - 10
IS - 39
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-65280
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea
A1 - Arai, Marylyn Setsuko
T1 - Upconversion nanoparticles for chemical, physical and biological sensing: from functionalization to point-of-care devices
N2 - Among several applications, versatile upconversion nanoparticles (UCNPs) which can convert lower-energy infrared radiation into higher-energy visible or ultraviolet light, have emerged as one of the most powerful tools in the field of chemical, physical and biological sensing. The use of UCNPs in fluorescent sensors allows non-invasive, highly sensitive, and selective detection methods, which are particularly beneficial in environments requiring minimal interference and high precision for analytes that can range from metal ions to biomolecules. In this lecture, an overview and the state of the art will be given, accompanied by examples of our recent contributions to key areas such as chronic disease diagnostics, bacterial sensing, and multifunctionally responsive nanoplatforms: (1) An Enhanced Luminescence Lateral-Flow Assay (ELLA) designed for rapid (< 15 min) and early detection of acute kidney injury biomarkers in urine samples, using a commercial cell phone camera, will be presented. The platform is based on Er³⁺- and Tm³⁺-doped UCNPs whose emissions intensities are 40-fold enhanced by an Au-coated mesoporous silica shell, enabling the accurate detection of KIM-1 and NGAL biomarkers with detection limits as low as 0.23 ng/mL; (2) Also, a multifunctional nanoplatform that combines Tm³⁺-doped UCNPs with a Cu(I) complex for applications in oxygen sensing, optical thermometry, and emission colour tuning will be presented. The platform utilizes Luminescent Resonance Energy Transfer (LRET) to achieve efficient energy transfer, enabling red emission from the Cu(I) complex while allowing the use of the UCNP’s original emissions for thermometry. The dual functionality allows sensitive O2 detection and temperature measurements, with relative sensitivities of up to 1% K⁻¹; (3) The critical challenge of rapid bacterial detection and differentiation was addressed by the development of a novel UCNP-based sensor. By functionalizing UCNPs with the antibiotics - vancomycin for Gram-(+) and polymyxin-B for Gram-(-), and using Au nanoparticles as intensity quenchers, the sensor leverages a ratiometric "turn-on" mechanism for selective detection of the bacteria, through changes in the green/red (G/R) ratio for Er-UCNP@PEG4-Van, and blue/red (B/R) ratio for Tm-UCNP@PEG4-Poly. By this approach, differentiation was possible over a wide concentration range of bacteria (0.05 to 5 x 105 CFU/mL) with high correlation with actual bacterial counts (r = 0.99 for S. aureus, r = 0.91 for E. coli); (4) Recently, we have demonstrated a water dispersable ratiometric pH-nanosensor based on host-guest interaction of Tm3+/Yb3+ co-doped UCNPs functionalized with b-cyclodextrin (b-CD) and a pH-responsive nitrobenzoxadiazol dye modified with adamantane (NBD-Ad). The sensor shows a ratiometric emission response (blue/red) over a pH range of 8.0 – 11.0 with high reproducibility, excellent reusability and selectivity, even in the presence of interferents. Together, the presented examples highlight the versatility and potential of UCNPs to develop novel sensors, offering measurable advances in diagnostics, environmental monitoring, and beyond.
T2 - Shift2025 - Spectral shaping for biomedical and energy applications
CY - Tenerife, Spain
DA - 13.10.2025
KW - Upconverting nanoparticles
KW - Fluorescent sensors
KW - Point-of-care devices
PY - 2025
AN - OPUS4-65282
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Camargo, Andrea
T1 - Enhanced emission of Nd3+ by localized silver nanocluster growth via direct laser writing in Ga-fluoride phosphate glasses
N2 - Gallium fluoride phosphate glasses are promising materials for optical applications in the visible to near infrared spectra due to their wide transmission window and ability to accommodate optically active dopants. In this study, melt quenched glasses in the compositional system 25Ga(PO₃)₃–20ZnF₂–30BaF₂–(25–x–y)SrF₂–xAgNO₃–yNdF₃ (x = 0 -10 mol%, y = 0 or 1 mol%) were studied and fully characterized by conventional and spectroscopic techniques to understand the interaction of silver species and Nd³⁺ ions. In Ag+ doped samples, the observation of a broad emission band in the visible spectrum evidences the overlapping presence of Ag⁺, Ag nanoclusters (NCs), and [Ag₂]²⁺ species. In the sample doped with 10 mol% Ag⁺, the development of a dark yellow color and alterations in the emission profile suggest the formation of Ag nanoparticles. In an attempt to control and increase the formation of Ag nanoclusters in a localized way, the glasses with 3 and 5 mol% Ag+ were subjected to direct laser writing (DLW) with femtosecond laser pulses at variable inscription intensities and scan speeds. As expected, the approach led to localized growth of Ag-NCs with precise spatial control and as a consequence, the Nd³⁺ emissions in the NIR region (e.g. at1060 nm) were significantly enhanced in laser-structured regions as compared to unmodified areas, evidencing efficient energy transfer from silver species to Nd³⁺ ions. These results demonstrate that DLW, applied for the first time in these glasses, enables precise spatial control over silver nanocluster formation, offering a viable route to process optical glasses for photonic applications.
T2 - XXIII - B-MRS Meeting
CY - Salvador, Brazil
DA - 28.09.2025
KW - Fluoride phosphate glasses
KW - Direct laser writting
KW - Neodymium
KW - Silver nanoclusters
PY - 2025
AN - OPUS4-65281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hallier, Dorothea C.
A1 - Radnik, Jörg
A1 - Dietrich, Paul M.
A1 - Seitz, Harald
A1 - Hahn, Marc Benjamin
T1 - Radiation damage to amino acids, peptides and DNA-binding proteins: the influence of water directly monitored by X-ray photoelectron spectroscopy
N2 - Ionizing radiation damage to biomolecules plays a crucial role in radiotherapy as a cancer treatment. Among these, DNA-binding proteins are of particular interest due to their pivotal roles in shielding DNA and facilitating its repair. Hence, in this study, we present first-ever recorded data of radiation damage to a protein monitored directly with near-ambient pressure (NAP) X-ray photoelectron spectroscopy (XPS) under a water atmosphere. This surface sensitive technique was used to in situ damage and probe gene-V protein (G5P, a model DNA-binding protein) under wet NAP conditions and dry vacuum (UHV) conditions to determine the effect of water on the radiation response. In addition, the X-ray radiation damage to selected pure amino acids and short homopeptides was determined to better understand the variety of damage mechanisms within the complex protein. In dry samples, drastic chemical changes were detected in all biomolecules dominated by fragmentation processes. Here, the breakage of peptide
bonds in the peptides and the protein are dominant. Surprisingly, hydration – despite introducing additional indirect damage pathways via water radiolysis – led to a reduction in overall radiation damage. This behaviour was attributed to hydration-dependent changes in reaction rates and respective deexcitation and damaging channels within the molecules and secondary species such as low-energy (LEE), (pre)-hydrated/(pre)-solvated electrons and radical species such as hydroxyl radicals.
KW - Radiation damage
KW - (Near-ambient pressure) X-ray photoelectron spectroscopy
KW - Ultra-high vacuum
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647565
DO - https://doi.org/10.1039/d5cp01887k
VL - 27
IS - 48
SP - 1
EP - 22
PB - Royal Society of Chemistry
AN - OPUS4-64756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amiri, Hesam
A1 - Nikookhesal, Aidin
A1 - Murugan, Divagar
A1 - Scholz, Stefan
A1 - Frentzen, Michael
A1 - Cao, Yuan
A1 - Nickl, Philip
A1 - Radnik, Jörg
A1 - Stockmann, Jörg M.
A1 - Vu, Xuan-Thang
A1 - Narayanan, Madaboosi S.
A1 - Knoch, Joachim
A1 - Ingebrandt, Sven
A1 - Adeli, Mohsen
A1 - Pachauri, Vivek
T1 - High precision correlative analysis of dielectric behavior evolution and anisotropy in graphene oxide thin film as a function of thermal annealing parameters
N2 - Graphene oxide (GO) and reduced graphene oxide (rGO) attract keen interest from different science and technology sectors owing to their tunable material characteristics dependent on C/O ratio. Thermal annealing in different gaseous environments serves as an effective approach to manipulate the C/O ratio in graphitic lattice, making it suitable for various electronic, optical and composites applications. Despite regular use of thermal annealing, systematic studies on dielectric properties evolution in GO against different annealing parameters remain elusive. This work reports on a reliable approach that adopts a joint Raman Spectroscopy, Mueller Matrix Spectroscopic Ellipsometry (MMSE) and high-precision electrical impedance spectroscopy (HP-EIS) framework for studying the evolution of dielectric behavior and anisotropies in GO. The experimental platform involved lithography-defined GO patterns connected to metal microelectrodes and glass passivation for protection from gaseous environments during annealing and measurements using Raman, MMSE and HP-EIS. The presented study delineates the effects of annealing parameters such as temperature, heating rate, and gaseous environment on GO permittivity. Novel findings include the discovery of a direct relationship between heating rate and dielectric properties, as well as determination of vertical limitation of MMSE for permittivity distribution characterization in GO, for the first time, to be around 8 nm.
KW - Thermal annealing
KW - Reduced graphene oxide
KW - Thin films
KW - 2D materials
KW - Spectroscopic ellipsometry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652428
DO - https://doi.org/10.1016/j.nwnano.2025.100130
SN - 2666-9781
VL - 11
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-65242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Rajotte, Isabelle
A1 - Thibeault, Marie-Pier
A1 - Sander, Philipp C.
A1 - Kodra, Oltion
A1 - Lopinski, Gregory
A1 - Radnik, Jörg
A1 - Johnston, Linda J.
A1 - Brinkmann, Andreas
A1 - Resch-Genger, Ute
T1 - Quantifying surface groups on aminated silica nanoparticles of different size, surface chemistry, and porosity with solution NMR, XPS, optical assays, and potentiometric titration
N2 - We assessed the quantification of surface amino functional groups (FGs) for a large set of commercial and custom-made aminated silica nanoparticles (SiO2 NPs) with sizes of 20–100 nm, prepared with different sol–gel routes, different amounts of surface amino FGs, and different porosity with four methods providing different, yet connected measurands in a bilateral study of two laboratories, BAM and NRC, with the overall aim to develop standardizable measurements for surface FG quantification. Special emphasis was dedicated to traceable quantitative magnetic resonance spectroscopy (qNMR) performed with dissolved SiO2 NPs. For the cost efficient and automatable screening of the amount of surface amino FGs done in a first step of this study, the optical fluorescamine assay and a potentiometric titration method were utilized by one partner, i.e., BAM, yielding the amount of primary amino FGs accessible for the reaction with a dye precursor and the total amount of (de)protonatable FGs. These measurements, which give estimates of the minimum and maximum number of surface amino FGs, laid the basis for quantifying the amount of amino silane molecules with chemo-selective qNMR with stepwise fine-tuned workflows, involving centrifugation, drying, weighting, dissolution, measurement, and data evaluation steps jointly performed by BAM and NRC. Data comparability and relative standard deviations (RSDs) obtained by both labs were used as quality measures for method optimization and as prerequisites to identify method-inherent limitations to be later considered for standardized measurement protocols. Additionally, the nitrogen (N) to silicon (Si) ratio in the near-surface region of the SiO2 NPs was determined by both labs using X-ray photoelectron spectroscopy (XPS), a well established surface sensitive analytical method increasingly utilized for microparticles and nano-objects which is currently also in the focus of international standardization activities. Overall, our results underline the importance of multi-method characterization studies for quantifying FGs on NMs involving at least two expert laboratories for effectively identifying sources of uncertainty, validating analytical methods, and deriving NM structure–property relationships.
KW - Advanced Materials
KW - Amino Groups
KW - Calibration
KW - Characterization
KW - Functional groups
KW - Method Comparison
KW - Nano Particle
KW - Validation
KW - XPS
KW - Optical Assay
KW - Quantification
KW - Surface Analysis
KW - Reference Materials
KW - Synthesis
KW - Fluorescence
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649992
DO - https://doi.org/10.1039/d5na00794a
VL - 7
IS - 21
SP - 6888
EP - 6900
PB - Royal Society of Chemistry
AN - OPUS4-64999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schusterbauer, Robert
A1 - Schünemann, Pia
A1 - Nickl, Philip
A1 - Er, Jasmin
A1 - Kämmer, Victoria
A1 - Junge, Florian
A1 - Fazzani, Salim
A1 - Mrkwitschka, Paul
A1 - Meermann, Björn
A1 - Haag, Rainer
A1 - Donskyi, Ievgen
T1 - Bifunctional Reduced Graphene Oxide Derivatives for PFOA Adsorption
N2 - Innovative materials are crucial for removing persistent pollutants per‐ and polyfluorinated alkyl substances (PFAS) from water. Here, a novel bifunctional reduced graphene oxide (TRGO) adsorbent is developed and characterized by advanced surface sensitive methods. Compared to pristine TRGO, the functionalized TRGO shows markedly improved PFAS removal efficiency and demonstrates strong potential for water purification applications.
KW - Adsorber
KW - PFAS
KW - HR-CS-GFMAS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651238
DO - https://doi.org/10.1002/ceur.202500240
SN - 2751-4765
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-65123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kim, K.J.
A1 - Kim, C.S.
A1 - Ruh, S. W.
A1 - Unger, Wolfgang
A1 - Radnik, Jörg
A1 - Mata-Salazar, J.
A1 - Juarez-Garcia, J.M.
A1 - Cortazar-Martinez, O.
A1 - Herrera-Gomez, A.
A1 - Hansen, P.E.
A1 - Madesen, J.S.
A1 - Senna, C.A.
A1 - Archanjo, B.S.
A1 - Damasceno, J.C.
A1 - Achete, C.A.
A1 - Wang, H.
A1 - Wang, M.
A1 - Windover, D.
A1 - Steel, E.
A1 - Kurokawa, A.
A1 - Fujimoto, T.
A1 - Azuma, Y.
A1 - Terauchi, S.
A1 - Zhang, L.
A1 - Jordaan, W.A.
A1 - Spencer, S.J.
A1 - Shard, A.G.
A1 - Koenders, L.
A1 - Krumrey, M.
A1 - Busch, I.
A1 - Jeynes, C.
T1 - Thickness measurement of nm HfO2 films
N2 - A pilot study for the thickness measurement of HfO2 films was performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The aim of this pilot study was to ensure the equivalency in the measurement capability of national metrology institutes for the thickness measurement of HfO2 films. In this pilot study, the thicknesses of six HfO2 films with nominal thickness from 1 nm to 4 nm were measured by X-ray Photoelectron Spectroscopy (XPS), X-ray Reflectometry(XRR), X-ray Fluorescence Analysis (XRF), Transmission Electron Spectroscopy (TEM), Spectroscopic Ellipsometry (SE) and Rutherford Backscattering Spectrometry (RBS). The reference thicknesses were determined by mutual calibration of a zero-offset method (Medium Energy Ion Scattering Spectroscopy (MEIS) of KRISS) and a method traceable to the length unit (the average thicknesses of three XRR data except the thinnest film). These reference thicknesses are traceable to the length unit because they are based on the traceability of XRR. For the thickness measurement by XPS, the effective attenuation length of Hf 4f electrons was determined. In the cases of XRR and TEM, the offset values were determined from a linear fitting between the reference thicknesses and the individual data by XRR and TEM. The amount of substance of HfO2, expressed as thickness of HfO2 films (in both linear and areal density units), was found to be a good subject for a CCQM key comparison.
To reach the main text of this paper, click on Final Report.
The final report has been peer-reviewed and approved for publication by the CCQM.
KW - Thickness measurements
KW - nm films
KW - X-ray Photoelectron Spectroscopy
KW - Mutual calibration
PY - 2021
DO - https://doi.org/10.1088/0026-1394/58/1A/08016
SN - 0026-1394
VL - 58
IS - 1a
SP - 08016
PB - IOP Publishing Lt.
CY - Bristol
AN - OPUS4-54175
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - The emp project smurfnano – Standardizing the quantification of surface functionalities, ligands, and coatings on nanomaterials
N2 - For industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage, meanwhile engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials.
These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented.
T2 - LNE Workshop
CY - Paris, France
DA - 04.11.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
AN - OPUS4-64725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smerechuk, Anastasiia
A1 - Guilherme Buzanich, Ana
A1 - Büchner, Bernd
A1 - Wurmehl, Sabine
A1 - Morrow, Ryan
T1 - Synthesis and properties of Sr2La2NiW2O12, a new S = 1 triangular lattice magnet
N2 - Magnetic materials featuring triangular arrangements of spins are frequently investigated as platforms hosting magnetic frustration. Hexagonal perovskites with ordered vacancies serve as excellent candidates for two-dimensional triangular magnetism due to the considerable separation of the magnetic planes. In this work, the effects of chemical pressure on the ferromagnetic ground state of Ba2La2NiW2O12 by substitution of Ba2+ with Sr2+ to produce Sr2La2NiW2O12 are investigated. The two materials are characterized using synchrotron-based XRD, XANES and EXAFS in addition to magnetometry in order to correlate their crystal structures and magnetic properties. Both materials form in space group R 3, yet as a result of the enhanced bending of key bond angles due to the effects of chemical pressure, the T C value of the magnetic Ni2+ sublattice is reduced from ∼6 K in Ba2La2NiW2O12 to 4 K in Sr2La2NiW2O12.
KW - XRD
KW - Magnetic materials
KW - EXAFS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652982
DO - https://doi.org/10.1107/S2052520624007091
SN - 2052-5206
VL - 80
IS - 5
SP - 467
EP - 473
PB - International Union of Crystallography (IUCr)
AN - OPUS4-65298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Interlaboratory comparisons as tool in advanced materials characterisation
N2 - Interlaboratory comparisons (ILCs) are an important tool for the validation of characterisation methods, and, herwith, a prerequisite for standardisation. The "Versailles Project on Advanced Materials and Standards" offers a framework for performing such ILCs: (i) TiO2 nanoparticles using ToF-SIMS, and (ii) the chemical composition of functionalized graphene using XPS. The results of both ILCs underline the importance of sample preparation for the measured results.
T2 - NanoMeasure France Meeting
CY - Online meeting
DA - 07.06.2024
KW - Standardisation
KW - Validation
KW - Interlaboratory comparison
KW - Graphene related 2D materials
KW - Titania nanoparticles
PY - 2024
AN - OPUS4-60532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - How to expand the use of your test method? Validation is key towards standardisation
N2 - Standardised methods need validation. The main validation parameters like trueness, repeatability and intermediate precision and reproducibility are presented. Furthermore, different methods for the validation are disussed: (certified) reference materials, representative testing materials and interlaboratory comparisons. At last, the need of proficiency testing is stressed.
T2 - Materials Week 2024
CY - Limassol, Cyprus
DA - 17.06.2024
KW - Validation
KW - Reproducibility crisis
KW - Metrological traceability
KW - Measurement uncertainty
PY - 2024
AN - OPUS4-60536
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Nanocarriers – Challenges Imposed by Material Characterization
N2 - A brief perspective of BAM on nanocarriers is presented including examples with special emphasis on the characterization of such materials and underlying challenges. In this respect, also ongoing activities at BAM on different types of core/shell nanomaterials and related systems are briefly summarized.
T2 - Kolloquium BfR
CY - Online meeting
DA - 18.03.2021
KW - Nanomaterial
KW - Nanocarrier
KW - Size
KW - Surface chemistry
KW - Release kinetics
KW - Chemical composition
KW - Core/shell nanoparticle
KW - Quantum dot
KW - Spectroscopy
KW - Fluorescence
PY - 2021
AN - OPUS4-52412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardised Measurements of Surface Functionalities on Nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. NP function, performance, interaction with biological species, and environmental fate are largely determined by their surface functionalities. Standardized repeatable surface characterization methods are therefore vital for quality control of NPs, and to meet increasing concerns regarding their safety. Therefore, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. This calls for fit-for-purpose, validated, and standardized methods, and reference data and materials on the surface chemistry of engineered NPs. Here, we present a concept for the development of such standardized measurement protocols utilizing method cross-validation and interlaboratory comparisons (ILCs) with emphasis on both advanced measurement methods such as quantitative Nuclear Magnetic Resonance (qNMR), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) and cost-efficient, non-surface specific methods like optical assays and electrochemical titration methods.
T2 - European Partnership on Metrology 2023 Review Conference
CY - Amsterdam, Netherlands
DA - 07.11.2023
KW - Surface chemistry
KW - Quality assurance
KW - Traceability
PY - 2023
AN - OPUS4-59142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scholtz, Lena
T1 - Standardized Measurements of Surface Functionalities on Nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely and commonly fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, their interaction with biological species, and also their environmental fate are largely determined by the surface functionalities of the particles. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, determination of their applicability, and mandatory to meet increasing concerns regarding their safety. In addition, industry as well as international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials.
However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized up until now. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR), as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter, typically less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required to provide well characterized test and reference nanomaterials including benchmark values.[1] These needs are addressed by the current European metrology project SMURFnano, involving 12 partners from different National Metrology Institutes, designated and research institutes, two university groups as well as one large company and one SME producing NPs. This project, as well as first results derived from the development of test and reference materials with a well characterized surface chemistry, and ongoing interlaboratory comparisons, will be presented.
T2 - eMRS - Fall Meeting 2025
CY - Warsaw, Poland
DA - 15.09.2025
KW - Nano
KW - Particle
KW - Silica
KW - Polymer
KW - Metrology
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - qNMR
KW - Validation
KW - Potentiometry
KW - XPS
PY - 2025
AN - OPUS4-64243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized TiO2 D540 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized TiO2 D540 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - TiO2 D540 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7961317
PB - Zenodo
CY - Geneva
AN - OPUS4-57669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Analytical & Characterisation Excellence in nanomaterial risk assessment: A tiered approach
N2 - The work packages of the EU H2020 project ACEnano are presented and their activities in standardization and guidance for regulators and SMEs.
T2 - ISO/TC 229 Strategy meeting
CY - Online meeting
DA - 10.11.2020
KW - Nanomaterials
KW - Standardization
KW - Risk assessment
PY - 2020
AN - OPUS4-51611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhatia, S.
A1 - Donskyi, Ievgen
A1 - Block, S.
A1 - Nie, C.
A1 - Burdinski, A.
A1 - Lauster, D.
A1 - Radnik, Jörg
A1 - Herrmann, A.
A1 - Haag, R.
A1 - Ludwig, K.
A1 - Adeli, M.
T1 - Wrapping and Blocking of Influenza A Viruses by Sialylated 2D Nanoplatforms
N2 - Inhibition of respiratory viruses is one of the most urgent topics as underlined by different pandemics in the last two decades. This impels the development of new materials for binding and incapacitation of the viruses. In this work, we have demonstrated that an optimal deployment of influenza A virus (IAV) targeting ligand sialic acid (SA) on a flexible 2D platform enables its binding and wrapping around IAV particles. A series of 2D sialylated platforms consisting graphene and polyglycerol are prepared with different degrees of SA functionalization around 10%, 30%, and 90% named as G-PG-SAL, G-PG-SAM, and G-PG-SAH, respectively. The cryo-electron tomography (Cryo-ET) analysis has proved wrapping of IAV particles by G-PG-SAM.
A confocal-based colocalization assay established for these materials has offered the comparison of binding potential of sialylated and non-sialylated nanoplatforms for IAV. With this method, we have estimated the binding potential of the G-PG-SAM and G-PG-SAH sheets for IAV particles around 50 and 20 times higher than the control sheets, respectively, whereas the low functionalized G-PG-SAL have not shown any significant colocalization value.
Moreover, optimized G-PG-SAM exhibits high potency to block IAV from
binding with the MDCK cells.
KW - 2D Materials
KW - Graphhene
KW - Influenza A virus
KW - Sialic acid
KW - wrapping
PY - 2021
DO - https://doi.org/10.1002/admi.202100285
VL - 8
IS - 12
SP - 285
PB - Wiley VCH
AN - OPUS4-52715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Elucidating core shell nanostructures with surface analytics
N2 - XPS is a versatile tool for elucidating core shell structures.
XPS can obtain information for organic compounds (polymer particle,
organic coating ) which are hardly or not detectable with other
Methods.
XPS is an important tool for the risk assessement of nanoparticles
T2 - Kratos German User Meeting
CY - Online meeting
DA - 26.05.2021
KW - Core-shell nanoparticles
KW - X-ray photoelectron spectroscopy
KW - Complementary methods
PY - 2021
AN - OPUS4-52717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized ZnO nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized ZnO nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - ZnO nanoparticles
KW - NanoSolveIT
PY - 2023
DO - https://doi.org/10.5281/zenodo.7990301
PB - Zenodo
CY - Geneva
AN - OPUS4-57661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andresen, Elina
T1 - Lanthanide-Based Upconverting Nanoparticles: Size, Shape, and Color Tuning for Emerging Applications in Sensing and Encoding
N2 - Lanthanide-based nanoparticles like upconversion nanoparticles (UCNP) consist of an inorganic host matrix doped with rare earth ions. These NPs have attracted considerable attention for different areas of application due to their unique spectral shifting potential providing multi-color luminescence in the UV/vis/NIR/SWIR.
Important prerequisites for the broad applicability of these nanomaterials are simple and robust synthesis protocols for UCNP with defined morphologies and tunable optical properties, and a sufficient stability under application-relevant conditions.
We built up a platform of UCNP based on AYF4 (A=alkali metal) host materials for usage as optical reporters, barcodes, sensors, and tags. This includes the synthesis of UCNPs with i) tunable size (10 – 150 nm), shape (spherical, rod-like, bipyramidal, etc.), and composition (Yb and Er/Tm as dopant ions) and ii) different core-shell architectures for emission color tuning. Therefore, we studied the reproducibility, robustness, and upscalability of the synthesis of β-NaYF4: Yb,Er UCNP via thermal decomposition and the tuning of UCNP size and shape by dopant ion ratios, host material, and reaction conditions and optically explored stability of selected UCNP in different environments under different application-relevant conditions. Subsequently, the applicability of these LnNPs for i) fabrication of security inks for printable QR codes, ii) design of self-referenced nanosensors for (micro)biologically relevant analytes, and iii) as NIR/SWIR luminescent reporters for optical imaging will be discussed. Aiming for core-shell architectures with defined UCL properties, we also assessed X-ray photoelectron spectroscopy depth-profiling methods for determining and quantifying lanthanide activator and sensitizer dopant ions within different types of LnNPs that is of key importance for UCL color and efficiency.
A platform of LnNPs based on NaYF4 and LiYF4 hosts with application-specifically tuned size, shape, composition, architecture, optical properties, and surface chemistry was realized.
T2 - MAF 2024
CY - Valencia, Spain
DA - 08.09.2024
KW - Lanthanide-based upconverting nanoparticles
KW - Sensing
KW - Encoding
PY - 2024
AN - OPUS4-62132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Where Do We Stand – Quantifying Amino Groups on Silica (Nano)Particles
N2 - Industry and regulators are increasingly requesting validated and standardized measurement protocols to support the manufacturing, quality control, and safe use of engineered nanomaterials. Addressing a remaining gap in method development and standardization for nanomaterial characterization, we investigated in a bilateral comparison various methods commonly used for surface functional group quantification, like quantitative nuclear magnetic resonance (qNMR) spectroscopy, x-ray photoelectron spectroscopy (XPS), and optical assays. These results demonstrate not only an influence of the size and synthesis methods on the number of surface functional groups for differently sized commercial and in-house synthesized silica nanoparticles but also on their functionality.
T2 - Kickoff-Meeting SMURFnano
CY - Berlin, Germany
DA - 09.07.2024
KW - Nano
KW - Particles
KW - Silica
KW - Synthesis
KW - Quantification
KW - Functional groups
KW - Quality assurance
KW - Reference material
KW - Interlaboratory comparison
KW - Method
KW - Uncertainty
KW - Sensor
KW - Surface analysis
PY - 2024
AN - OPUS4-62164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized CeO2 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized CeO2 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - CeO2 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7941461
PB - Zenodo
CY - Geneva
AN - OPUS4-57667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Advanced Materials for the Energy Transition
N2 - Advanced Materials are crucial for the sucess of the energy transition. 10 relevant advanced materials were chosen and their role for relevant technologies was analysed. Challenges regarding their safe and sustainable use are discussed.
T2 - OECD WPMN SG Advanced Materials Teleconference
CY - Online meeting
DA - 30.09.2025
KW - Solar Cells
KW - Advanced Carbon Materials
KW - Fuel Cells
KW - Batteries
KW - Hydrogen Storage
PY - 2025
AN - OPUS4-64306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reed, B.P.
A1 - Marchesini, S.
A1 - Chemello, Giovanni
A1 - Morgan, D.J.
A1 - Vyas, N.
A1 - Howe, T.
A1 - Radnik, Jörg
A1 - Clifford, C,A.
A1 - Pollard, A.J.
T1 - The influence of sample preparation on XPS quantification of oxygen-functionalised graphene nanoplatelets
N2 - X-ray photoelectron spectroscopy (XPS) is widely used for characterising the chemistry of graphene-related two-dimensional materials (GR2M), however the careful preparation of the sample for analysis is important in obtaining representative quantifications. We report an investigation by three laboratories showing that the preparation method for oxygen-functionalised graphene nanoplatelet (GNP) powders has a significant effect on the homogeneous-equivalent elemental composition measured in XPS. We show that pressing GNP powders onto adhesive tapes, into recesses, or into solid pellets results in inconsistencies in the XPS quantification. The measured oxygen-to-carbon atomic ratio from GNP pellets depends upon the die pressure used to form them and the morphology of the GNPs themselves. We recommend that powder samples of GR2Ms are pelletised prior to XPS analysis to improve repeatability and reproducibility of measurements.
KW - X-ray photoelectron spectroscopy
KW - Graphene related two-dimensional materials (GR2M)
KW - Pelletization
KW - Powder
PY - 2023
DO - https://doi.org/10.1016/j.carbon.2023.118054
SN - 0008-6223
VL - 211
SP - 1
EP - 6
PB - Elsevier Ltd.
AN - OPUS4-57694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hülagü, Deniz
A1 - Hirahara, Kenta
A1 - Fischer, Daniel
A1 - Florian, Camilo
A1 - Schusterbauer, Robert
A1 - Ermilova, Elena
A1 - Krüger, Jörg
A1 - Unterreiner, Andreas-Neil
A1 - Bonse, Jörn
A1 - Hertwig, Andreas
T1 - Using imaging ellipsometry to understand femtosecond laser materials processing of group IV materials
N2 - Laser materials processing is an important tool for creating and shaping new materials. Laser machining, especially with ultrashort pulses offers the modification of surfaces, thin coatings, and bulk materials with an unprecedented precision and control. The most desired feature of pulsed laser processing in the femtosecond range is that the heat-affected zone in the irradiated material will be extremely small. To better understand the mechanisms involved during laser irradiation, it is important to analyse the outcome of light-matter interaction with spectroscopic methods. Ellipsometry, especially spectroscopic imaging ellipsometry (SIE), has become an important tool for this in recent times, as it gives access to local layer thicknesses, materials dielectric functions, and features like changes in surface roughness.
This work includes an overview over our recent studies examining near-infrared fs-laser surface processing of different group IV materials. The superficial phase change of silicon from crystalline to amorphous has been investigated in the past as the result of laser processing strongly depends on the crystal orientation. Moreover, SIE is capable of determining the
properties of buried a-Si interfaces with micrometer lateral and sub-nanoneter vertical precision. Additionally, the growth of native and laser-induced oxides can be revealed.
T2 - ICSE10 - 10th International Conference on Spectroscopic Ellipsometry
CY - Boulder, CO, USA
DA - 08.06.2025
KW - Laser surface ablation
KW - Amorphous Carbon
KW - Silicon
KW - Correlative Imaging Ellipsometry
PY - 2025
AN - OPUS4-63633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Characterization and quantification of functional groups and coatings on nanoobjects an overview
N2 - Characterization of Nanoparticles – Questions to Ask, Functional Nanoparticles (NPs) – Organic, Inorganic, and Hybrid Nanoparticles Nanomaterial Characterization Standardization – Addressing Remaining Gaps Surface FGs Particle Surface Chemistry - Why is it Important? Particle Surface Chemistry - A Key Driver for Performance, Applications, and Safety Aspects Method Development for Quantifying FGs and Ligands on Particle Surfaces FG Quantification – Method Choice & Criteria Relevant for Data Interpretation Quantifying the Amount of Total and Accessible FGs on Aminated Silica Nanoparticles (SiO2-NH2) Comparing the Total and Accessible –NH2 Content on Aminated Silica NPs of Different Size Characterization of Nanoparticles Standardization Standardized Measurements of Surface FGs on Nanoparticles EMP Project SMURFnano EMP Project SMURFnano Work Packages & Goals Certified Reference Materials from BAM
T2 - e-MRS 2024 (Spring Meeting of the European Materials Research Society, Altech Symposium)
CY - Strasbourg, France
DA - 27.05.2024
KW - Luminescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Quality assurance
KW - Interlaboratory comparison
KW - Method
KW - Uncertainty
KW - Reference material
KW - Surface analysis
KW - Optical assay
KW - NMR
KW - Silica
KW - Ligand
PY - 2024
AN - OPUS4-60495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
T1 - Quantifying the Total and Accessible Number of Surface Functional Groups and Ligands on Engineered Nanomaterials Using a Multimodal Approach
N2 - Functionalized nanomaterials (NM) with their unique size-dependent properties are of increasing relevance for current and future developments in various fields such as medical and pharmaceutical industry, computing, electronics or food and consumer products. For instance, NMs are used as drug carriers, fluorescent sensors, and multimodal labels in bio-analytical assays and imaging applications. The performance and safety of NMs are influenced by their intrinsic physicochemical properties. Among these, the surface chemistry of the particles, which is largely determined by the chemical nature and density of functional groups and ligands, plays a crucial role in enhancing the stability, and processability of NMs, as well as their interactions with the environment. Thus, particle standards with well-designed surfaces and methods for functional group quantification can foster the sustainable development of functional and safe(r) NM.[1] To develop simple, versatile, and multimodal tools for quantifying various bioanalytically relevant functional groups (FG) such as amine,[2,3] carboxy,[2] thiol, and aldehyde[4] functionalities, we explored and compared several analytical methods. These methods included electrochemical titration, dye-based optical assays, and other instrumental techniques like nuclear magnetic resonance, mass spectrometry, and thermal analysis. Our multimodal approach’s potential for FG quantification was demonstrated using both commercial and custom-made polymeric and silica particles with different densities of functional groups.
T2 - ANAKON 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Quality Assurance
KW - Nano Particle
KW - qNMR
KW - Potentiometry
KW - Reference Material
KW - Surface Analysis
KW - Advance Materials
KW - Functional Group
KW - Silica
KW - Synthesis
KW - Optical Assays
KW - Reference Data
PY - 2025
AN - OPUS4-65000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Co2.25Fe0.75O4 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Co2.25Fe0.75O4 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Co2.25Fe0.75O4 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7940538
PB - Zenodo
CY - Geneva
AN - OPUS4-57663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - The SMURFnano project - standardized measurements of surface functionalities on nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, optoelectronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required and well characterized test and reference nanomaterials providing benchmark values.[1] These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented.
T2 - eMRS
CY - Strasbourg, France
DA - 27.05.2025
KW - Quality assurance
KW - Reference analysis
KW - Standardization
KW - Metrology
KW - Reference products
KW - Reference materials
KW - Mission
KW - Surface chemistry
KW - Nano
KW - Particle
KW - qNMR
KW - XPS
KW - Fluorescence
KW - Optical assays
KW - Interlaboratory comparison
KW - Uncertainty
PY - 2025
AN - OPUS4-63243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
A1 - Tavernaro, Isabella
A1 - Abram, Sarah-Luise
A1 - Homann, Christian
A1 - Scholtz, Lena
A1 - Radnik, Jörg
T1 - Validated and standardized measurements and quantification of surface functionalities on nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage which improve the quality of life and European prosperity. Nanoparticle function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, regulatory agencies, and policymakers need validated traceable measurement methods and reference materials. Industry, e.g., must comply with various regulations, including the chemicals´ regulation REACH (2006/1907) and cosmetic products regulation (2009/1223), depending on the use. Therefore, standardization organizations such as the European Committee for Standardization (CEN), the International Organization for Standardization (ISO), and the International Electrotechnical Commission (IEC) as well as industrial stakeholders, European Medicine Agency (EMA), and the nanosafety community responsible for guidelines for nanomaterial (NM) regulation like the Organisation for Economic Co-operation and Development (OECD) have expressed needs for standardized methodologies to measure NP surface chemical properties.
Despite these needs, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Specifically, validated quantitative procedures for the measurement of thickness and composition of nanoparticle coatings and other surface functionalities are needed. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required. These needs have been addressed by us in two interlaboratory comparisons, that will be presented. In addition, the European metrology project SMURFnano will be briefly presented involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs.
T2 - NanoCarbon Annual Conference 2025
CY - Würzburg, Germany
DA - 18.03.2025
KW - Nano
KW - Particle
KW - Silica
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - QNMR
KW - Validation
KW - Potentiometry
KW - XPS
PY - 2025
AN - OPUS4-62790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brinkmann, A.
T1 - A qNMR Method for Quantification of Surface Functional Groups on Silica Nanoparticles: Bilateral Comparisons
N2 - Nanomaterials (NM) of different size, shape, morphology, composition, and surface chemistry are used in a wide range of applications, including medical diagnostics, and imaging and consumer products. The importance of an adequate and reliable characterization is crucial for quality control during NM production, for ensuring an optimum function for the desired application, and for risk assessment studies. Currently there is a lack of reliable and validated methods and reference materials for quantifying NM surface functional groups, despite the importance of surface chemistry for the production of colloidally stable materials, further processing steps, and the interaction with the environment and biological species.
Following our initial study on the use of qNMR for quantifying the amount of amino groups on surface modified silica (1), we have carried out two bilateral comparisons between NRC and BAM to further develop and optimize a reliable protocol for these measurements (2,3), using aminated silica nanoparticles prepared by multiple methods, both commercial and in-house synthesized, and with varying amine content. Solution qNMR is based on dissolving aminated silica nanoparticles in strong base to release the surface grafted amino silane molecules, followed by the quantification of these molecules by solution qNMR using an internal standard. This method provides the amount of total amino groups present in the sample, which can differ from probe accessible or surface-sensitive measurements performed with X-Ray photoelectron spectroscopy (XPS). Complementary measurements using optical assays, involving a labeling step with a dye reporter, and XPS are employed to assess the probe accessible and surface amine content for representative samples. These measurements, which illustrate the advantages and potential limitations of the different characterization methods, will contribute to establish a basis for testing the protocol in an international inter-laboratory comparison and for standardization at ISO Technical Committee 229 – Nanotechnologies.
T2 - BERM
CY - Halifax, Canada
DA - 01.06.2025
KW - Quality assurance
KW - Nano
KW - Particle
KW - Synthesis
KW - Advanced materials
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Surface
KW - qNMR
KW - Optical assay
KW - Interlaboratory comparison
KW - Metrology
KW - Standardization
PY - 2025
AN - OPUS4-63527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tavernaro, Isabella
A1 - Abram, Sarah-Luise
A1 - Homann, Christian
A1 - Scholtz, Lena
A1 - Radnik, Jörg
A1 - Resch-Genger, Ute
T1 - Validated and standardized measurements and quantification of surface functionalities on nanoparticles
N2 - Surface-functionalized organic and inorganic engineered nanomaterials (NMs) are widely applied in the life and materials sciences. NM performance depends on key factors such as particle size and shape, crystal phase, morphology, chemical composition, and surface chemistry, i.e., surface coatings, functional groups (FGs), and ligands.1 The latter controls their processability and interaction with the environment and largely their possible toxicity. Thus, methods for FG quantification are important tools for quality control of NM production processes and can foster the sustainable development of functional and safe(r) NMs. This underlines the importance of validated and standardized analytical methods for surface analysis and reference materials.2 This encouraged us to explore simple and versatile tools for quantifying common bioanalytically relevant FGs such as optical assays, electrochemical titration methods, quantitative nuclear magnetic resonance spectroscopy (qNMR), and X-Ray photoelectron spectroscopy (XPS) and to perform a first interlaboratory comparison (ILC) on surface FG quantification.3,4 In a follow-up ILC, BAM and NRC explored qNMR sample preparation, measurement, and data evaluation protocols for commercial and custom-made aminated SiO2 NPs with sizes of 20-100 nm, different amounts of surface amino FGs, and different porosity.5,6 First, the number of amino FGs accessible for a dye reporter was determined with a cost-efficient, automated optical fluorescamine assay. Then, qNMR workflows and protocols were stepwise fine-tuned. The qNMR ILC was complemented by joint XPS measurements. BAM also examined the applicability of fast and automatable potentiometric titrations to screen the total amount of (de)protonable FGs on aminated SiO2 NPs. Our results underline the need to evaluate protocols for FG quantification in ILCs and the advantages of multi-method characterization strategies for efficient method cross validation.
T2 - Surface and Micro/Nano Analysis Working Group
CY - Paris, France
DA - 08.04.2025
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nano
KW - Particle
KW - Surface analysis
KW - XPS
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - QNMR
KW - Potentiometry
PY - 2025
AN - OPUS4-62969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portesi, C.
T1 - qNMR for standardised measurements of surface functionalities on nanoparticles
N2 - Engineered nanoparticles have a large application potential in fields such as medicine, sensing, catalysis, energy storage, and opto-electronics [1]. The applicability and performance of engineered nanoparticles is largely determined by their surface chemistry, i.e. functional groups and ligands on the particle surface. However, documented standards to quantify functional groups and ligands currently do not exist. Such standards are required to support quality control of nanomaterial production and surface modification processes, and safe-by-design concepts and to meet regulatory requirements.
Here, this issue is addressed by developing and standardizing quantitative Nuclear Magnetic Resonance (qNMR) methods for the characterization of surface functionalized nanoparticles which specifically address the determination of the amount and chemical composition of surface functionalities and coatings.
This work is being developed under the EMP project 23NRM02 SMURFnano - Standardised measurements of surface functionalities on nanoparticles. qNMR competence of 7 qNMR laboratories involved in the project was first tested with a molecular model sample i.e. citrate, to be assessed in terms of purity. Citrate is often used as hydrophilic surface ligand for different nanoparticles. Then, the first nanoparticle samples, here a set of aminated SiO2 NPs [1] with a particle size of 100 nm and two amino group densities, prepared and characterized by BAM regarding size and surface charge as well as stability over 21 months with an optical assay and qNMR, were assessed in an international interlaboratory comparison (ILC) on qNMR. Thereby, the amount of surface amino groups introduced by grafting of the silica cores with different amounts of 3-aminopropyl)triethoxysilane (APTES) was quantified by each participant following a sample preparation protocol previously developed by BAM and NRC.The results of the ILC were then used to refine the protocol for sample preparation and to identify critical points for qNMR measurement and data analysis.
This work will contribute to the development of a Preliminary Work Item (PWI) 19257 (ISO/TC 229) on surface functional groups and coatings on nano-objects. Also, it will lay the groundwork to perform ILCs on the quantification and determination of the amount of surface functional groups under the roof of VAMAS TWA2 (Surface Chemical Analysis) for different types of nanomaterials possessing industry-relevant surface functionalities using qNMR. These ILCs will be complemented by other techniques like X-Ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS).
T2 - BERM
CY - Halifax, Canada
DA - 01.06.2025
KW - Quality assurance
KW - Nano
KW - Particle
KW - Synthesis
KW - Advanced materials
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Surface
KW - qNMR
KW - Optical assay
KW - Interlaboratory comparison
KW - Metrology
KW - Validation
KW - Standardization
PY - 2025
AN - OPUS4-63443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Quantifying the total and accessible amount of surface functionalities and ligands on nano-materials: Overview and recommended methods
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. This calls for reliable, reproducible, and standardized surface characterization methods, which are vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Validated and standardized workflows for surface analysis are also increasingly requested by industry, international standardization organizations, regulatory agencies, and policymakers. To establish comparable measurements of surface functionalities across different labs and ease instrument performance validation, reference test materials and reference materials of known surface chemistry as well as reference data are needed.
In the following, different methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques are presented and discussed regarding method-inherent advantages and limitations. Special emphasis is dedicated to traceable quantitative nuclear magnetic resonance (qNMR), X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods.
T2 - LNE Workshop
CY - Paris, France
DA - 04.11.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - Fluorescamine
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
AN - OPUS4-64726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardized Measurements of Surface - Functionalities on Nanoparticles
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, optoelectronics, and information storage. NP function, interaction with biological species, and environmental fate are largely determined by surface functionalities. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, and mandatory to meet increasing concerns regarding their safety. Also, industry, international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials. However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR) as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required and well characterized test and reference nanomaterials providing benchmark values.[1] These needs are addressed by the recently started European metrology project SMURFnano involving 12 partners from different National Metrology Institutes, designated institutes, and research institutes, two university groups as well as one large company and one SME producing NPs. This project as well as first results derived from the development of test and reference materials with a well characterized surface chemistry and ongoing interlaboratory comparisons will be presented.
T2 - eMRS
CY - Strasbourg, France
DA - 27.05.2025
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Silica
KW - Upconversion nanoparticles
KW - Optical assay
KW - qNMR
KW - Surface analysis
KW - Ligand
KW - Quantification
KW - Functional group
KW - XPS
KW - ToF-SIMS
KW - Polymer particle
KW - Surface modification
KW - Potentiometry
KW - Metrology
KW - Method
KW - Validation
KW - ILC
PY - 2025
AN - OPUS4-63339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Resch-Genger, Ute
T1 - Standardized Measurements of Surface Functionalities on Nanoparticles - F. Synthesis and characterization of functional nanocomposite materials
N2 - Engineered nanoparticles (NPs) with various chemical compositions and surface functionalities are routinely and commonly fabricated for industrial applications such as medical diagnostics, drug delivery, sensing, catalysis, energy conversion and storage, opto-electronics, and information storage. NP function, their interaction with biological species, and also their environmental fate are largely determined by the surface functionalities of the particles. Reliable, reproducible, and standardized surface characterization methods are therefore vital for quality control of NPs, determination of their applicability, and mandatory to meet increasing concerns regarding their safety. In addition, industry as well as international standardization organizations, regulatory agencies, and policymakers need validated and standardized measurement methods and reference materials.
However, methodologies for determining NP surface properties, including the amount, chemical composition, and homogeneity of surface functionalities and coatings are largely non-standardized up until now. Suitable methods for determining surface functionalities on ligand-stabilized core and core/shell NPs include advanced techniques such as traceable quantitative nuclear magnetic resonance (qNMR), as well as X-ray electron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF-SIMS), and simpler optical and electrochemical methods. The latter, typically less costly methods are often used by SMEs, e.g., for quality control. To validate methods, establish measurement uncertainties, test reference materials, and produce reference data, international interlaboratory comparisons (ILC) on NP surface functionalization measurements are required to provide well characterized test and reference nanomaterials including benchmark values.[1] These needs are addressed by the current European metrology project SMURFnano, involving 12 partners from different National Metrology Institutes, designated and research institutes, two university groups as well as one large company and one SME producing NPs. This project, as well as first results derived from the development of test and reference materials with a well characterized surface chemistry, and ongoing interlaboratory comparisons, will be presented.
T2 - Shift 2025
CY - La Laguna, Tenerife
DA - 13.10.2025
KW - Nano
KW - Particle
KW - Silica
KW - Iron oxide
KW - Lanthanide
KW - Metrology
KW - Quality assurance
KW - Reference material
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Method
KW - Optical assay
KW - qNMR
KW - Validation
KW - Potentiometry
KW - XPS
KW - ILC
KW - Standardization
PY - 2025
AN - OPUS4-64370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - Physico-chemical characterization of sterilized Fe2O3 nanoparticles by XPS / HAXPES / SEM
N2 - Here a dataset of XPS, HAXPES and SEM measurements for the physico-chemical characterization of sterilized Fe2O3 nanoparticles is presented. The measurements are part of the H2020 project “NanoSolveIT”.
KW - XPS
KW - HAXPES
KW - SEM
KW - NanoSolveIT
KW - Fe2O3 nanoparticles
PY - 2023
DO - https://doi.org/10.5281/zenodo.7941001
PB - Zenodo
CY - Geneva
AN - OPUS4-57665
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, M.
A1 - Schlaich, C.
A1 - Zhang, J.
A1 - Donskyi, Ievgen
A1 - Schwibbert, Karin
A1 - Schreiber, Frank
A1 - Xia, Y.
A1 - Radnik, Jörg
A1 - Schwerdtle, T.
A1 - Haag, R.
T1 - Mussel-inspired multifunctional coating for bacterial infection prevention and osteogenic induction
N2 - Bacterial infection and osteogenic integration are the two main problems that cause severe complications after surgeries. In this study, the antibacterial and osteogenic properties were simultaneously introduced in biomaterials, where copper nanoparticles (CuNPs) were generated by in situ reductions of Cu ions into a mussel-inspired hyperbranched polyglycerol (MI-hPG) coating via a simple dip-coating method. This hyperbranched polyglycerol with 10 % catechol groups’ modification presents excellent antifouling property, which could effectively reduce bacteria adhesion on the surface. In this work, polycaprolactone (PCL) electrospun fiber membrane was selected as the substrate, which is commonly used in biomedical implants in bone regeneration and cardiovascular stents because of its good biocompatibility and easy post-modification. The as-fabricated CuNPs-incorporated PCL membrane [PCL-(MI-hPG)-CuNPs] was confirmed with effective antibacterial performance via in vitro antibacterial tests against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and multi-resistant E. coli. In addition, the in vitro results demonstrated that osteogenic property of PCL-(MI-hPG)-CuNPs was realized by upregulating the osteoblast-related gene expressions and protein activity. This study shows that antibacterial and osteogenic properties can be balanced in a surface coating by introducing CuNPs.
KW - Mussel-inspired coating
KW - CuNPs
KW - Multi-resistant bacteria
KW - Antibacterial
KW - Antifouling
KW - Osteogenesis
PY - 2021
DO - https://doi.org/10.1016/j.jmst.2020.08.011
SN - 1005-0302
VL - 68
SP - 160
EP - 171
PB - Elsevier Ltd.
AN - OPUS4-51519
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arinchtein, A.
A1 - Schnack, R.
A1 - Kraffert, K.
A1 - Radnik, Jörg
A1 - Dietrich, P.
A1 - Sachse, René
A1 - Krähnert, R.
T1 - Role of Water in Phase Transformations and Crystallization of Ferrihydrite and Hematite
N2 - The oxides, hydroxides, and oxo-hydroxides of iron belong to the most abundant materials on earth. They also feature a wide range of practical applications. In many environments, they can undergo facile phase transformations and crystallization processes.
Water appears to play a critical role in many of these processes. Despite numerous attempts, the role of water has not been fully revealed yet. We present a new approach to study the influence of water in the crystallization and phase transformations of iron oxides.
The approach employs model-type iron oxide films that comprise a defined homogeneous nanostructure. The films are exposed to air containing different amounts of water reaching up to pressures of 10 bar. Ex situ analysis via scanning electron microscopy, Transmission electron microscopy, selected area electron diffraction, and X-ray diffraction is combined with operando near-ambient pressure X-ray photoelectron spectroscopy to follow water-induced changes in hematite nd ferrihydrite. Water proves to be critical for the nucleation of ematite domains in ferrihydrite, the resulting crystallite orientation, and the underlying crystallization mechanism.
KW - Iron oxide
KW - Ferrihydrite
KW - Hematite
KW - Water
KW - NAP-XPS
KW - High pressure
PY - 2020
DO - https://doi.org/10.1021/acsami.0c05253
VL - 12
SP - 38714
EP - 38722
PB - ACS Publication
AN - OPUS4-51201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stockmann, Jörg M.
T1 - Reference material for the determination of the field of view of small-area X-ray photoelectron spectrometers
N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces. For evaluating the quality of such microstructures, it is crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. The aperture has a major influence on the signal-contribution from the outside. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize the FoV: The signal-contribution from the outside is reduceable down to lower than 50 %, when the aperture is 30 % of the structure dimension for our Kratos AXIS Ultra DLD system.
T2 - Kratos User's Meeting 2020
CY - Online meeting
DA - 21.09.2020
KW - Small-area XPS
KW - Field of View
KW - Imaging XPS
KW - Reference Material
PY - 2020
AN - OPUS4-51412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stockmann, Jörg M.
T1 - New Test Specimen for the Determination of the Field of View of Small-Area XPS
N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces. For evaluating the quality of such microstructures, it is crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. The aperture has a major influence on the signal-contribution from the outside. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize the FoV: The signal-contribution from the outside is reduceable down to lower than 50 %, when the aperture is 30 % of the structure dimension for our Kratos AXIS Ultra DLD system.
T2 - Kratos User's Meeting 2020
CY - Online meeting
DA - 21.09.2020
KW - Small Area XPS
KW - Reference Material
KW - Imaging XPS
KW - Field of View
PY - 2020
AN - OPUS4-51413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - Just a minute: X-ray scattering
N2 - An extremely brief summary of what X-ray scattering can do for you (X-ray scattering encompasses small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS/XRD), amongst others). See my other videos for more detailed explanations on sample selection, data correction, data analysis, etc.
KW - X-ray scattering
KW - Introduction
KW - Materials science
KW - Nanostructure investigation
KW - MOUSE
PY - 2022
UR - https://www.youtube.com/watch?v=jWWNQyaCTHA
DO - https://doi.org/10.26272/opus4-55768
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-55768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guitton-Spassky, Tiffany
A1 - Schade, Boris
A1 - Zoister, Christian
A1 - Veronese, Eleonora
A1 - Rosati, Marta
A1 - Baldelli Bombelli, Francesca
A1 - Cavallo, Gabriella
A1 - Thünemann, Andreas
A1 - Ghermezcheshme, Hassan
A1 - Makki, Hesam
A1 - Netz, Roland R.
A1 - Ludwig, Kai
A1 - Metrangolo, Pierangelo
A1 - Singh, Abhishek Kumar
A1 - Haag, Rainer
T1 - Fluorinated Hexosome Carriers for Enhanced Solubility of Drugs
N2 - Designing nanomaterials for drug encapsulation is a crucial, yet challenging, aspect for pharmaceutical development. An important step is synthesizing amphiphiles that form stable supramolecular systems for efficient drug loading. In the case of fluorinated drugs, these have superior properties and also a tendency toward reduced water solubility. For the first time, we report here fluorinated hexosome carriers made from nonionic dendritic amphiphiles, capable of encapsulating the fluorinated drug Leflunomide with high efficiency (62 ± 3%) and increasing its solubility by 12-fold. We synthesized amphiphiles with varying tail groups (fluorinated/alkylated), and their supramolecular self-assembly was investigated using cryogenic transmission electron microscopy and small-angle X-ray scattering. Furthermore, Leflunomide and its equivalent nonfluorinated counterpart were encapsulated within fluorinated and nonfluorinated assemblies. Self-assembly and encapsulation mechanisms were well supported by coarse-grained molecular simulations, yielding a fundamental understanding of the new systems.
KW - PEFAS
KW - Small-angle X-ray scattering
KW - SAXS
KW - Reference method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632002
DO - https://doi.org/10.1021/jacsau.5c00198
SN - 2691-3704
VL - 5
IS - 5
SP - 2223
EP - 2236
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-63200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Qiang
A1 - Heuchel, Matthias
A1 - Thünemann, Andreas
A1 - Machatscheck, Rainhard
T1 - The role of diffusion in the hydrolytic degradation of poly(lactic-co-glycolic acid): A molecular perspective
N2 - This research emphasizes the importance of internal surface erosion as a key factor in the hydrolytic degradation of PLGA (poly(D,L-lactic-co-glycolic acid)) providing an alternative view of the established surface and bulk erosion degradation modes. Using molecular dynamics (MD) simulations, this study reveals the role of water and oligomer diffusion during the degradation of PLGA and highlights the importance of water channels formed as the overall water content increases. We found that these continuous water channels play a crucial role in accelerating the transport of water and the release of degradation products from the polymer matrix, as the diffusion coefficients of water and small oligomers exhibit significant differences spanning 2 to 3 orders of magnitude between the water and polymer phases. Water follows a different diffusion mechanism than polymer fragments. The diffusion rate of the fragments up to a size of octamers was found to be size-dependent and reasonably well approximated by a 1/N behavior, in line with the Rouse model.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - PLGA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621250
DO - https://doi.org/10.1016/j.polymdegradstab.2024.111119
VL - 232
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-62125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Alyna
A1 - Holtzheimer, Lea
A1 - Clarke, Coby
A1 - Thünemann, Andreas
A1 - Taubert, Andreas
T1 - Complex Self-Organization in n-Alkylammonium Sulfobetaine Zwitterions with High Thermal Stabilities and High Expansion Coefficients
N2 - Sulfobetaine zwitterions made from n-alkyl dimethylamines and butanesultone yield a series of n-alkylammonium sulfobetaine zwitterions with complex self-organization behavior. The compounds are thermally quite stable and the length of the alkyl chain directly affects all phase transition temperatures of the compounds: the longer the alkyl chain, the higher the transition temperature. All compounds exhibit lamellar order and the different phases are characterized by a lower temperature orthorhombic and a higher temperature hexagonal in-plane order. The phase transition from the orthorhombic to the hexagonal phase is always associated with an increase of the long period. The phase transition is also associated with a rather high thermal expansion coefficient.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanostructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626276
DO - https://doi.org/10.1021/acs.langmuir.4c02892
SN - 1520-5827
VL - 41
SP - 4422
EP - 4434
PB - American Chemical Society (ACS)
AN - OPUS4-62627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kieserling, Helena
A1 - Sieg, Holger
A1 - Heilscher, Jasmin
A1 - Drusch, Stephan
A1 - Braeuning, Albert
A1 - Thünemann, Andreas
A1 - Rohn, Sascha
T1 - Towards Understanding Particle-Protein Complexes: Physicochemical, Structural, and Cellbiological Characterization of β-Lactoglobulin Interactions with Silica, Polylactic Acid, and Polyethylene Terephthalate Nanoparticles
N2 - Nanoplastic particles and their additives are increasingly present in the food chain, interacting with biomacromolecules with not yet known consequences. A protein corona forms around the particles in these usually complex matrices, primarily with a first contact at surface-active proteins. However, systematic studies on the interactions between the particles and proteins –especially regarding protein affinity and structural changes due to surface properties like polarity – are limited. It is also unclear whether the protein corona can "mask" the particles, mimic protein properties, and induce cytotoxic effects when internalized by mammalian cells. This study aimed at investigating the physicochemical properties of model particle-protein complexes, the structural changes of adsorbed proteins, and their effects on Caco-2 cells. Whey protein β-lactoglobulin (β-Lg) was used as a well-characterized model protein and studied in a mixture with nanoparticles of varying polarity, specifically silica, polylactic acid (PLA), and polyethylene terephthalate (PET). The physicochemical analyses included measurements of the hydrodynamic diameter and the zeta potential, while the protein conformational changes were analyzed using Fourier-transform-infrared spectroscopy (FTIR) and intrinsic fluorescence. Cellular uptake in Caco-2 cells was assessed through flow cytometry, cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, and cellular impedance was analyzed with xCELLigence® technology. The results indicated that β-Lg had the highest affinity for hydrophilic silica particles, forming silica-β-Lg complexes and large aggregates through electrostatic interactions. The affinity decreased for PLA and was lowest for hydrophobic PET, which formed smaller complexes. Adsorption onto silica caused partial unfolding and refolding of β-Lg. The silica-β-Lg complexes were internalized by Caco-2 cells, impairing cell proliferation. In contrast, PLA- and PET-protein complexes were not internalized, though PLA complexes slightly reduced cell viability. This study enhances our understanding of protein adsorption on nanoparticles and its potential biological effects.
KW - Nanoplastics
KW - Microplastics
KW - Reference materials
KW - Scattering
KW - DLS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630093
DO - https://doi.org/10.1016/j.colsurfb.2025.114702
SN - 1873-4367
VL - 253
SP - 1
EP - 12
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mikhlin, Yuri
A1 - Muzikansky, Anya
A1 - Zysler, Melina
A1 - Thünemann, Andreas
A1 - Zitoun, David
T1 - Emerging electrochemistry of high-concentration colloids: Redox-activity, wide potential window and electrophoretic transport of iron oxide nanoparticles
N2 - High-concentration, steric stabilizer free colloids and particularly their electrochemical behavior remains almost unexplored. Herein, we report on the electrochemistry (cyclic voltammetry, impedance spectroscopy, etc.) of highly concentrated aqueous colloidal dispersion up to 800 g/L of citrate-capped ∼11 nm Fe3-xO4 nanoparticles (NPs) without background electrolyte on glassy carbon electrodes. X-ray photoelectron spectroscopy was applied to analyze the reaction products. Solid-state Fe(II)/Fe(III) conversion was concluded to determine the cathodic and anodic faradaic reactions of the particles, with the currents depending on approximately square root of the concentration. The electrochemical reactions are coupled with the electrophoretic transfer of the negatively charged NPs on toward the anode, with the ohmic-type behavior in the bulk demonstrated by the nearly linear voltametric cathodic curves and frequency-independent impedance above ∼10–100 Hz. Accumulation and clogging of the NPs retards diffusion near anode. Hydrogen and especially oxygen evolution are arrested, and very large oxidation overpotentials result in extraordinary wide, up to 12 V, electrochemical window of water stability. The findings shed light onto basic features of the electrochemistry of high-concentration colloids without added electrolyte and their potential applications in redox flow batteries, electrophoretic deposition and beyond.
KW - Nanoplastics
KW - SAXS
KW - Small-angle X-ray scattering
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644340
DO - https://doi.org/10.1016/j.jcis.2025.139247
SN - 0021-9797
VL - 703
SP - 1
EP - 18
PB - Elsevier Inc.
AN - OPUS4-64434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Moschner, J.
A1 - Mikolajczak, D. J.
A1 - Becker, M.
A1 - Thünemann, Andreas
A1 - Kästner, Claudia
A1 - Klemczak, D.
A1 - Stegemann, A.-K.
A1 - Böttcher, C.
A1 - Metrangolo, P.
A1 - Netz, R. R.
A1 - Koksch, B.
T1 - The Impact of Halogenated Phenylalanine Derivatives on NFGAIL Amyloid Formation
N2 - The hexapeptide hIAPP22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild‐type hIAPP′s toxicity to β‐cell death. In amyloid research, the role of hydrophobic and aromatic‐aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic‐aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) to study the impact of side‐chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self‐assembly process.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Nanostructure
KW - Peptide
KW - Amyloid
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518632
DO - https://doi.org/10.1002/cbic.202000373
VL - 21
IS - 24
SP - 3544
EP - 3554
PB - Wiley
CY - Weinheim
AN - OPUS4-51863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liebig, F.
A1 - Sarhan, R. M.
A1 - Schmitt, C. N. Z.
A1 - Thünemann, Andreas
A1 - Prietzel, C.
A1 - Bargheer, M.
A1 - Koetz, J.
T1 - Gold Nanotriangles with Crumble Topping and their Influence on Catalysis and Surface‐Enhanced Raman Spectroscopy
N2 - By adding hyaluronic acid (HA) to dioctyl sodium sulfosuccinate (AOT)‐stabilized gold nanotriangles (AuNTs) with an average thickness of 7.5±1 nm and an edge length of about 175±17 nm, the AOT bilayer is replaced by a polymeric HA‐layer leading to biocompatible nanoplatelets. The subsequent reduction process of tetrachloroauric acid in the HA‐shell surrounding the AuNTs leads to the formation of spherical gold nanoparticles on the platelet surface. With increasing tetrachloroauric acid concentration, the decoration with gold nanoparticles can be tuned. SAXS measurements reveal an increase of the platelet thickness up to around 14.5 nm, twice the initial value of bare AuNTs. HRTEM micrographs show welding phenomena between densely packed particles on the platelet surface, leading to a crumble formation while preserving the original crystal structure. Crumbles crystallized on top of the platelets enhance the Raman signal by a factor of around 20, and intensify the plasmon‐driven dimerization of 4‐nitrothiophenol (4‐NTP) to 4,4′‐dimercaptoazobenzene in a yield of up to 50 %. The resulting crumbled nanotriangles, with a biopolymer shell and the absorption maximum in the second window for in vivo imaging, are promising candidates for biomedical sensing.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
KW - Gold
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503977
DO - https://doi.org/10.1002/cplu.201900745
VL - 85
IS - 3
SP - 519
EP - 526
PB - Wiley-VCH Verlag
CY - Weinheim
AN - OPUS4-50397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Smales, Glen Jacob
A1 - Clark, Adam H.
A1 - Thünemann, Andreas
T1 - Zinc Phosphate Nanoparticles Produced in Saliva
N2 - This paper reports the formation of zinc phosphate nanoparticles from the artificial digestion of zinc chloride. Initially, the formation of amorphous primary particles with a mean radius of 1.1 nm is observed, alongside the formation of larger, protein stabilized aggregates. These aggregates, with a radius of gyration of 37 nm, are observed after 5 minutes of exposure to artificial saliva and are shown to be colloidally stable for a minimum time of two weeks. The initially formed primary particles are thought to consist of amorphous zinc phosphate, which is then transformed into crystalline Zn3(PO4)2·4H2O over the course of two weeks. Our results demonstrate that the interaction of inorganic salts with bodily fluids can induce the formation of de novo nanoparticles, which in turn, provides insights into how zinc‐enriched foods may also facilitate the formation of nanoparticles upon contact with saliva. As such, this may be considered as an undesirable (bio)mineralization.
KW - SAXS
KW - Digestion
KW - Zinc phosphate
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514239
DO - https://doi.org/10.1002/ejic.202000521
IS - 38
SP - 3654
EP - 3661
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Schmidt, R. F.
A1 - Sahoo, A. K.
A1 - tom Dieck, T.
A1 - Hohmann, T.
A1 - Schade, B.
A1 - Brademann-Jock, Kerstin
A1 - Thünemann, Andreas
A1 - Netz, R. R.
A1 - Gradzielski, M.
A1 - Koksch, B.
T1 - Rational design of amphiphilic fluorinated peptides: Evaluation of self-assembly properties and hydrogel formation
N2 - Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune their biophysical properties and intermolecular interactions. In particular, the degree of fluorination plays a crucial role in peptide engineering as it can be used to control the characteristics of fluorine-specific interactions and, thus, peptide conformation and self-assembly. Here, we designed and explored a series of amphipathic peptides by incorporating the fluorinated amino acids (2S)-4-monofluoroethylglycine (MfeGly), (2S)-4,4-difluoroethylglycine (DfeGly) and (2S)-4,4,4-trifluoroethylglycine (TfeGly) as hydrophobic components. This approach enabled studying the impact of fluorination on secondary structure formation and peptide self-assembly on a systematic basis. We show that the interplay between polarity and hydrophobicity, both induced differentially by varying degrees of side chain fluorination, does affect peptide folding significantly. A greater degree of fluorination promotes peptide fibrillation and subsequent formation of physical hydrogels in physiological conditions. Molecular simulations revealed the key role played by electrostatically driven intra-chain and inter-chain contact pairs that are modulated by side chain fluorination and give insights into the different self-organization behaviour of selected peptides. Our study provides a systematic report about the distinct features of fluorinated oligomeric peptides with potential applications as peptide-based biomaterials.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Amyloid
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553504
DO - https://doi.org/10.1039/D2NR01648F
SN - 2040-3364
VL - 14
IS - 28
SP - 10176
EP - 10189
PB - Royal Society of Chemistry
AN - OPUS4-55350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Yokosawa, T.
A1 - Spiecker, E.
A1 - Klinger, D.
T1 - Regioselective Seeded Polymerization in Block Copolymer Nanoparticles: Post-Assembly Control of Colloidal Features
N2 - Post-assembly modifications are efficient tools to adjust colloidal features of block copolymer (BCP) particles. However, existing methods often address particle shape, morphology, and chemical functionality individually. For simultaneous control, we transferred the concept of seeded polymerization to phase separated BCP particles. Key to our approach is the regioselective polymerization of (functional) monomers inside specific BCP domains. This was demonstrated in striped PS-b-P2VP ellipsoids. Here, polymerization of styrene preferably occurs in PS domains and increases PS lamellar thickness up to 5-fold. The resulting asymmetric lamellar morphology also changes the particle shape, i.e., increases the aspect ratio. Using 4-vinylbenzyl azide as co-monomer, azides as chemical functionalities can be added selectively to the PS domains. Overall, our simple and versatile method gives access to various multifunctional BCP colloids from a single batch of pre-formed particles.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Polymer
KW - Nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557246
DO - https://doi.org/10.1002/anie.202208084
SN - 1433-7851
VL - 61
IS - 35
SP - 1
EP - 11
PB - Wiley
CY - Weinheim
AN - OPUS4-55724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, M. B.
A1 - Fahrenson, C.
A1 - Givelet, L.
A1 - Herrmann, T.
A1 - Loescher, K.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
A1 - Sieg, H.
T1 - Beyond microplastics ‑ investigation on health impacts of submicron and nanoplastic particles after oral uptake in vitro
N2 - The continuously increasing use of plastics is supposed to result in a rising exposure of MNPs to humans. Available data on human health risks of microplastics after oral uptake increased immensely in the past years and indicates very likely only low risks after oral consumption. Concerning nanoplastics, uptake, transport and potential adverse effects after oral uptake are less well understood. This study aims to investigate differences between microplastic particles and particles in the submicron- and nanoscaled size derived from food-relevant polymers with a particle size range consistent with higher potential for cellular uptake, fate, and effects when applied to human intestinal and liver cells. This work includes the development of cellular and subcellular detection methods for synthetic polymeric particles in the micro- and nanometer-range, using Scanning Electron Microscopy, Small-Angle X-ray and Dynamic Light Scattering methods, Asymmetric Flow Field Flow Fractionation, octanol-water fractionation, fluorescence microscopy and flow cytometry. Polylactic acid (250 nm and 2 μm (polydisperse)), melamine formaldehyde (366 nm) and polymethylmethacrylate (25 nm) were thoroughly characterized. The submicro- and nanoplastic test particles showed an increased uptake and transport quantity through intestinal cells. Both types of particles resulted in observed differences of uptake behavior, most likely influenced by different lipophilicity, which varied between the polymeric test materials. Toxic effects were detected after 24 h only in overload situations for the particles in the submicrometer range. This study provides further evidence for gastrointestinal uptake of submicro- and nanoplastics and points towards differences regarding bioavailability between microplastics and smaller plastic particles that may result following the ingestion of contaminated food and beverages. Furthermore, the results reinforce the importance for studying nanoplastics of different materials of varying size, surface properties, polymer composition and hydrophobicity.
KW - Small-angle X-ray scattering
KW - SAXS
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550741
DO - https://doi.org/10.1186/s43591-022-00036-0
VL - 2
SP - 1
EP - 19
PB - Springer Nature
AN - OPUS4-55074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Klinger, D.
T1 - Solvent Annealing of Striped Ellipsoidal Block Copolymer Particles: Reversible Control over Lamellae Asymmetry, Aspect Ratio, and Particle Surface
N2 - Solvent annealing is a versatile tool to adjust the shape and morphology of block copolymer (BCP) particles. During this process, polar solvents are often used for block-selective swelling. However, such water-miscible solvents can induce (partial) solubilization of one block in the surrounding aqueous medium, thus, causing complex structural variations and even particle disassembly. To reduce the complexity in morphology control, we focused on toluene as a nonpolar polystyrene-selective solvent for the annealing of striped polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) ellipsoids. The selective stretching of PS chains produces unique asymmetric lamellae structures, which translate to an increase in the particle aspect ratio after toluene evaporation. Complete reversibility is achieved by changing to chloroform as a nonselective solvent. Moreover, surfactants can be used to tune block-selective wetting of the particle surface during the annealing; for example, a PS shell can protect the internal lamellae structure from disassembly. Overall, this versatile postassembly process enables the tailoring of the structural features of striped colloidal ellipsoids by only using commercial BCPs and solvents.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Polymer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543731
DO - https://doi.org/10.1021/acsmacrolett.1c00665
VL - 11
IS - 3
SP - 319
EP - 335
PB - American Chemical Society
AN - OPUS4-54373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, L.
A1 - Hoche, E.
A1 - Stock, V.
A1 - Böhmert, L.
A1 - Braeuning, A.
A1 - Thünemann, Andreas
A1 - Sieg, H.
T1 - Intestinal and hepatic effects of iron oxide nanoparticles
N2 - Iron oxide nanoparticles gain increasing attention due to their broad industrial use. However, safety concerns exist since their effects on human cells are still under investigation. The presence of iron oxide nanoparticles in the food pigment E172 has been shown recently. Here, we studied four iron oxide nanoparticles, one food pigment E172 and the ionic control FeSO4 regarding dissolution in biological media, uptake and transport, and cellular effects in vitro in human intestinal Caco-2 and HepaRG hepatocarcinoma cells. The iron oxide nanoparticles passed the gastrointestinal passage without dissolution and reached the intestine in the form of particles. Minor uptake was seen into Caco-2 cells but almost no transport to the basolateral site was detected for any of the tested particles. HepaRG cells showed higher particle uptake. Caco-2 cells showed no alterations in reactive oxygen species production, apoptosis, or mitochondrial membrane potential, whereas two particles induced apoptosis in HepaRG cells, and one altered mitochondrial membrane potential at non-cytotoxic concentrations. No correlation between physicochemical particle characteristics and cellular effects was observed, thus emphasizing the Need for case-by-case assessment of iron oxide nanoparticles.
KW - Nanoparticles
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521651
DO - https://doi.org/10.1007/s00204-020-02960-7
VL - 95
IS - 3
SP - 895
EP - 905
PB - Springer
AN - OPUS4-52165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Rybak, Tina
A1 - Thünemann, Andreas
T1 - Microwave-Assisted Synthesis of ZnO Nanoparticles: Phase Transfer to Water
N2 - Herein, a simple one-pot procedure is reported to obtain aqueous zinc oxide (ZnO) nanoparticle dispersions from ZnO nanoparticles dispersed in cyclohexane. In the process, polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80) functions as a phase transfer agent and colloidal stabilizer. The particles grow in a defined manner during the transfer, presumably via coalescence. The final particle radii are tuneable in the range from 2.3 ± 0.1 nm to 5.7 ± 0.1 nm depending on the incubation time of the dispersion at 90 °C. Small-angle X-ray scattering is employed to determine the particle radius distributions before and after phase transfer. The larger ZnO particle radii are associated with a redshift of the optical bandgap and luminescence emission, as expected for semiconductor nanoparticles. The particles presented here exhibit a relative size distribution width of 20%, rendering them attractive for applications in, e.g., biology or catalysis. The latter application is demonstrated at the photocatalytic degradation of methylene blue dye.
KW - SAXS
KW - Small-angle X-ray scattering
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551502
DO - https://doi.org/10.1002/adem.202101276
VL - 24
IS - 6
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-55150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Maxi B.
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Loeschner, Katrin
A1 - Givelet, Lucas
A1 - Fahrenson, Christoph
A1 - Braeuning, Albert
A1 - Sieg, Holger
T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics
N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles.
KW - Toxicology
KW - Nanoparticles
KW - Dynamic Light Scattering
KW - Nanoplastics
KW - Microplastics
KW - Reference Method
KW - Reference Material
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947
DO - https://doi.org/10.1016/j.fct.2023.114423
SN - 0278-6915
VL - 184
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-59394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, Holger
A1 - Schaar, Caroline
A1 - Fouquet, Nicole
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Braeuning, Albert
T1 - Particulate iron oxide food colorants (E 172) during artificial digestion and their uptake and impact on intestinal cells
N2 - Iron oxide of various structures is frequently used as food colorant (E 172). The spectrum of colors ranges from yellow over orange, red, and brown to black, depending on the chemical structure of the material. E 172 is mostly sold as solid powder. Recent studies have demonstrated the presence of nanoscaled particles in E 172 samples, often to a very high extent. This makes it necessary to investigate the fate of these particles after oral uptake. In this study, 7 differently structured commercially available E 172 food colorants (2 x Yellow FeO(OH), 2 x Red Fe2O3, 1 x Orange Fe2O3 + FeO(OH) and 2 x Black Fe3O4) were investigated for particle dissolution, ion release, cellular uptake, crossing of the intestinal barrier and toxicological impact on intestinal cells. Dissolution was analyzed in water, cell culture medium and artificial digestion fluids. Small-angle X-ray scattering (SAXS) was employed for determination of the specific surface area of the colorants in the digestion fluids. Cellular uptake, transport and toxicological effects were studied using human differentiated Caco-2 cells as an in vitro model of the intestinal barrier. For all materials, a strong interaction with the intestinal cells was observed, albeit there was only a limited dissolution, and no toxic in vitro effects on human cells were recorded.
KW - Toxicology
KW - Nanoparticles
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593935
DO - https://doi.org/10.1016/j.tiv.2024.105772
VL - 96
SP - 1
EP - 12
PB - Elsevier BV
AN - OPUS4-59393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, Jana
A1 - Taubert, Andreas
A1 - Thünemann, Andreas
T1 - Synthesis and Characterization of Ultra‐Small Gold Nanoparticles in the Ionic Liquid 1‐Ethyl‐3‐methylimidazolium Dicyanamide, [Emim][DCA]
N2 - AbstractWe report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long‐term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4 ⋅ 3 H2O) with the ionic liquid 1‐ethyl‐3‐methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small‐angle X‐ray scattering (SAXS), UV‐Vis spectroscopy, and MALDI‐TOF mass spectrometry. A three‐stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz‐Slyozov‐Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters.
KW - Reference materials
KW - SAXS
KW - Gold
KW - Nanoparticle
KW - Small-angle X-ray scattering
KW - Ionic liquid
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588203
DO - https://doi.org/10.1002/open.202300106
SN - 2191-1363
VL - 44
SP - 1
EP - 19
PB - Wiley
AN - OPUS4-58820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, Jana
A1 - Thünemann, Andreas
T1 - Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics
N2 - Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D h = 180.5 ± 5.8 nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of 𝜻 = −43 ± 2 mV.
KW - Nanoparticles
KW - Reference Material
KW - Nanoplastics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571799
DO - https://doi.org/10.1002/marc.202200874
SN - 1022-1336
VL - 44
IS - 6
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Iannuzzi, Maurizio
T1 - Rational design of polyfluorinated peptide-based materials: Self-assembly of an amphiphilic motif
N2 - Generation of a pH sensitive amphiphilic block oligopeptide containing the bioactive function RGD and a library of derivatives varying the length of the hydrophobic core and the degree of side chain fluorination. Peptide rational design enables us to obtain desired features (pH sensitivity etc.). The introduction of fluorine alters a wide range of peptide properties such as secondary structure propensity, folding, thermal and metabolic stability and proteolytic resistance. The RGD function is highly effective at promoting the attachment of numerous cell types to a plethora of materials. This small sequence is the principal integrin-binding domain present within ECM proteins such as fiobronectin, vibronectin and fibrinogen. For this reason, RGD containing peptides offer several advantages for biomaterials applications. The use of RGD compared with native ECM proteins, minimized the risk of immune reactivity or pathogen transfer. Herein in this work, we present the peptide motif X6RGD and its fluoro-derivates for prospective receptor-specific drug delivery in cancer theraphy. Overall, our results demonstrate that high degree of fluorination achieved triggers a selective modification of peptide self-assembly dramatically improving the structural properties, the carrier suitability, enzimatic degradation profiles and cytotoxic features of the fluoropeptide conjugate(s).
T2 - 37th European Peptide Symposium
CY - Florence, Italy
DA - 25.08.2024
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
PY - 2024
DO - https://doi.org/10.17952/37EPS.2024.P1302
AN - OPUS4-62139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - STOP and Scatter
N2 - We present first X-ray scattering results for the Horizon Europe project "Surface Transfer of Pathogens" (STOP) and an outlook regarding X-ray scattering methods on thin films, which are under development at the MOUSE.
T2 - M17 full project meeting - Surface Transfer of Pathogens (STOP)
CY - EMPA, St. Gallen, Switzerland
DA - 18.01.2024
KW - X-ray Scattering
KW - Grazing incidence
PY - 2024
AN - OPUS4-62723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - Next Level Grazing Incidence: Let the Standardization Begin
N2 - Reproducibility of experiments is something most natural scientists would consider important. However, how do we know experiments are comparable between instruments without explicitly disclosing, tracking and discussing instrument calibration and data processing methods? At SXNS17 we would like to introduce our standardization initiative to the Grazing Incidence Small-Angle Scattering (GISAS) community and gather initial feedback and perhaps contributors before we proceed further.
From the point of view of development of a new lab GISAXS setup at BAM (Berlin, Germany), we propose a draft autoalignment and calibration routine. Together with the GISAS community, we would like to further develop this routine into a standard. On that basis, agreed-upon methods for data treatment could be the next step for the future and perhaps an organization like the Open Reflectometry Standards Organisation .
We begin with a survey of hardware in use around the world, an area we are not planning to address in terms of standardization but which nonetheless provides the practical background for our efforts. We assume availability of pitch, roll, y and z motions, those may be present in the form of a stack of stages, a hexapod, or even a robot arm. All of these can be used for GISAS, but specifications such as backlash direction and minimum incremental motion need to be considered when it comes to resolution and repeatability of experiments. We ask for your help in gathering information on sample stages and holders and would like to present the results at the International Small-Angle Scattering Conference (SAS2024) in November 2024. We believe this an important step to ensure any developed standard can work for everyone in the end.
Inspired by work for Grazing Incidence X-ray Diffraction one of our goals is to estimate and propagate uncertainties from stage motions to scattering vector q (compare for Small-Angle X-ray Scattering). Further ideas for standardization include the use of reflectometry in choosing angles of incidence and, perhaps more importantly, data corrections.
T2 - Surface X-ray and Neutron Scattering 17 (SXNS17)
CY - EPN, Grenoble, France
DA - 15.07.2024
KW - Grazing incidence scattering
KW - Sample alignment
KW - Community survey
KW - Calibration
PY - 2024
AN - OPUS4-62724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - (Grazing Incidence) Small-angle X-ray Scattering for STOP
N2 - We remind project partners of the principles of SAXS, GISAXS and X-ray reflectivity and their applicability to the antimicrobial particles and coatings developed within the STOP project.
T2 - M25 project meeting: Surface Transfer of Pathogens (STOP)
CY - Bucharest, Romania
DA - 19.09.2024
KW - X-ray Scattering
KW - Nanomaterial
PY - 2024
AN - OPUS4-62774
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Harmonising Tribotests of Polymers in Hydrogen
N2 - This talk harmonised methods to investigate friction and wear of commercial and experimental polymer compounds in hydrogen using several tribometers.
T2 - Surface Ventures - Symposium on Hydrogen Tribology
CY - Online meeting
DA - 31.07.2025
KW - Hydrogen
KW - Polymers
KW - Tribometer
KW - Wear
KW - Coefficient of Friction
KW - Interlaboratory comparison
KW - Comparability
KW - Harmonisation
KW - Standardisation
KW - Tribology
KW - Oil-coupled compounds
KW - FAIR data
KW - Database
KW - i-TRIBOMAT
PY - 2025
AN - OPUS4-63838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hewel, M.
A1 - Siemann, U.
A1 - Smarsly, B.
A1 - Stribeck, A.
A1 - Thünemann, Andreas
T1 - Nachruf auf Wilhelm Ruland
N2 - Mit Prof. Dr. Wilhelm Ruland starb am 3. Februar 2021 einer der letzten großen Wissenschaftler, welche die Streutheorie nach dem Zweiten Weltkrieg vorangetrieben haben. Sein zentrales Thema war die Streuung an weicher Materie. Hier lieferte er bis ins hohe Alter grundlegende Beiträge, die den Stellenwert seines Leitspruchs demonstrieren: Nichts ist praktischer als eine gute Theorie.
KW - SAXS
PY - 2021
VL - 20
IS - 4
SP - 50
EP - 50
PB - Wiley
AN - OPUS4-52413
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thünemann, Andreas
T1 - SAXS for the development of reference materials: Silver nanoparticles, a case study
N2 - Today there are hundreds of products available containing silver in form of nanoparticles, so-called nanosilver. This situation and the foreseeable future growing market of nanosilver will supposedly cause an increased release of silver into the environment. In this way, silver can be also incorporated into the human body and accumulated in different organs, which can be toxic or at least an unknown risk to human health. For these reasons, it is important to constantly study materials containing silver nanoparticles, their production, application in products and technical processes, dissemination of silver nanoparticles in the environment, and effects on humans and nature. The state-of-the-art nanoparticle size and concentration characterization are illustrated in an extensive interlaboratory comparison. To guarantee the traceability of measurements and to secure the comparison of results of different analytical methods, reference materials (RM) and certified reference materials (CRM) are essential. As a case study, the objective of the presented project was to provide an aqueous suspension of silver nanoparticles as a reference material with a nominal diameter below 10 nm for application in the determination of the size and concentration of nanoparticles in an aqueous surrounding. Measurands are the particles’ diameter D, size distribution width σ, number density N, and concentration c. Target uncertainties, defined as one sigma of the measurand values, are 5% for D, 10% for σ, 20% for N, and 20% for c. The certification was carried out based on ISO 17867 and the relevant ISO-Guides to produce reference material. The process of using SAXS as a reliable method for testing homogeneity and short-term and long-term stability of the material is reported. The particle preparation is described in detail so that the user can carry out the steps of synthesis and characterization in his own laboratory if required. Optionally, one can also contact the author for the provision of the silver nanoparticles. Detailed information can be found elsewhere (BAM Certification Reports, BAM-N008 (2022)).
T2 - SAXS excites
CY - Graz, Austria
DA - 04.04.2023
KW - Nanoparticles
KW - SAXS
KW - Nanosilver
KW - Small-angle x-ray scattering
PY - 2023
AN - OPUS4-57283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Tribological performance of polymer compounds in gaseous hydrogen
N2 - In this study, friction and wear of conventional and alternative high performance polymer compounds, typically used for components of compressors, were investigated in gaseous hydrogen and nitrogen up to 80 bar of gas pressure. The compounds used were a commercial PEEK matrix with 10 wt.% each of PTFE, graphite, and short carbon fibres, a PPS matrix with 10 wt.% each of PTFE and graphite, and an experimental PA12 matrix with PTFE chemically coupled with an oleyl alcohol. Due to the cylindrical shape of the polymer samples, the contact area and pressure change if wear occurs. Therefore, experimental results of pre-screening tests have been used as input for FEM and an analytical model to determine the decreasing contact pressure over time. Afterwards, the outcome of the models was used to determine the duration of the experiments to reach typical contact pressures of seals in hydrogen compressors.
T2 - ASMET TriboCorrosion International Conference 2025
CY - Vienna, Austria
DA - 23.10.2025
KW - Hydrogen
KW - Polymer
KW - Tribometer
KW - Comparability
KW - Harmonisation
KW - Oil-coupled compounds
KW - Coefficient of Friction
KW - Wear
KW - FAIR data
KW - Standardisation
KW - Tribology
KW - Database
KW - i-TRIBOMAT
PY - 2025
AN - OPUS4-64473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thünemann, Andreas
T1 - Structure Analysis of Functional Hydrogels with Small-Angle X-ray Scattering (SAXS)
N2 - Hydrogel properties are largely determined by their network structure. Here, we report on the capabilities of SAXS methods for characterizing polymer-network gels. SAXS provides rich insight into different types and levels of nanostructural inhomogeneities in these soft matter materials. The structure analysis of alginate hydrogels, typically utilized in tissue engineering applications, will be discussed in detail.
T2 - Polydays 2024
CY - Berlin, Germany
DA - 30.09.2024
KW - SAXS
KW - Small-angle X-ray scattering
KW - Polymer
KW - Gel
PY - 2024
AN - OPUS4-61184
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Theiler, Geraldine
A1 - Gradt, Thomas
T1 - Influence of counterface and environment on the tribological behaviour of polymer materials
N2 - This paper focuses on the influence of the counterface materials on the sliding behaviour of polymer materials in hydrogen. Polyimide (PI), polyetheretherketone (PEEK) and Polytetrafluoroethylene (PTFE) materials were investigated against hardened 52100 martensitic bearing steel and 304 austenitic stainless steel with similar roughness (Ra = 0.2 μm). Results indicate that the friction and wear of PI and PEEK materials depend on the counterface material. This effect wasn’t observed for PTFE composites. While the tribological performance of polyimide is better against 52100 in hydrogen, improved sliding behaviour of PEEK materials is observed with 304 counterface, particularly at higher sliding speed. Surface analyses of the transfer film reveal that the influence of the counterface is primarily related to the chemical nature of the steel for PI and to the thermal conductivity of the disc for PEEK materials.
KW - Friction
KW - Wear
KW - Polymers
KW - Hydrogen Transfer Film
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515483
DO - https://doi.org/10.1016/j.polymertesting.2020.106912
VL - 93
SP - 106912
PB - Elsevier Ltd.
AN - OPUS4-51548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
T1 - Influence of the counterface on the sliding behavior of polymer materials in hydrogen
N2 - This presentation deals with the influence of the counterface materials on the sliding behaviour of some polymer materials in hydrogen. Polyimide (PI), polyetheretherketone (PEEK) and Polytetrafluoroethylene (PTFE) materials were investigated against hardened 52100 martensitic bearing steel and 304 austenitic stainless steel with similar roughness (Ra = 0.2 μm). Results indicate that the friction and wear of PI and PEEK materials depend on the counterface material. This effect wasn’t observed for PTFE composites.
While the tribological performance of polyimide is better against 52100 in hydrogen, improved sliding behaviour of PEEK materials is observed with 304 counterface, particularly at higher sliding speed. Surface analyses of the transfer film reveal that the influence of the counterface is primarily related to the chemical nature of the steel for PI and to the thermal conductivity of the disc for PEEK materials.
T2 - Hydrogenius & I2CNER Tribology Symposium
CY - Online meeting
DA - 29.01.2021
KW - Polymers
KW - Hydrogen
KW - Counterface
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-52093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giannakopoulos, Antonios E.
A1 - Zisis, Athanasios
A1 - Zervaki, Anna D.
A1 - Dimopoulos, Christos D.
A1 - Platypodis, Efstathios
A1 - Eberwein, Robert
T1 - Effective elastic moduli and failure mechanisms of a random assembly of thin walled glass microbubbles
N2 - In this work a methodology is presented to estimate the elastic properties and failure mechanisms of an assembly of random, brittle microbubbles. The approach is based on the mechanics of frictionless micro-contact between hollow spherical shells by employing relations from classical shell theory and verified by two dimensional axisymmetric Finite Elements. The estimated values are in agreement with available experimental values. Moreover, a granular type analytical homogenization model provides an isotropic elastic constitutive law to be used for the macroscopic deformation of an assembly of glass micro-bubbles when it is compressed by external loads. In addition, approximate estimates are also proposed for two important micro-failure mechanisms of such assemblies that relate either to the splitting or to the buckling of a brittle spherical shell, prior its complete crushing. The results are novel and are expected to enhance the application of glass microbubbles directly in acute thermal insulation problems such as liquid hydrogen storage.
KW - LH2
KW - Cryogenic Vessels
KW - Insulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634354
DO - https://doi.org/10.1016/j.ijsolstr.2025.113528
SN - 0020-7683
VL - 320
SP - 1
EP - 11
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
T1 - Tribology of polymeric materials in gaseous and liquid hydrogen
N2 - This presentation gives an overview of the tribological behaviour of polymeric materials in gaseous and luquid hydrogen.
T2 - HYDROGENIUS-BAM Joint Hydrogen Symposium
CY - Online meeting
DA - 06.07.2021
KW - Polymers
KW - Hydrogen
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-53701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
T1 - Benchmarking of polymer materials for tribological applications in hydrogen
N2 - The focus of this study is to evaluate of hydrogen on the friction and wear behavior of a wide range of polymer materials. Thereby, the tribological performance of filled and unfilled polymers from different suppliers were compared at room temperature in air and hydrogen gas (H2) as well as in liquid hydrogen at -253°C (LH2).
T2 - 62. Tribologie-Fachtagung der Gesellschaft für Tribologie e. V.
CY - Online meeting
DA - 27.09.2021
KW - Polymers
KW - Hydrogen
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-53700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Aqueous Dispersions of polypropylene as possible reference material for nanoplastics
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastics are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a "methodological gap" in the analytics of plastic particles with a diameter smaller than 1 µm. Submicron and nanoplastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastics found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics such as polypropylene (PP). We found an easy way to form nanoparticles consisting of PP (nano-PP), adapting and improving the method presented for polystyrene (PS). Nano-PP was formed via a top-down method where the polymer was dispersed to acetone and then transferred to water. No additional surfactant is needed to obtain a dispersion which is stable for more than 35 weeks.
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering (DLS). The chemical analysis of the nanoplastics was performed via Fourier Transform Infrared spectroscopy. To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
T2 - European Polymer Congress 2022
CY - Prag, Czechia
DA - 26.06.2022
KW - Nanoplastic
PY - 2022
AN - OPUS4-55960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, H.
A1 - Klusmann, L.
A1 - Ellermann, A. L.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
T1 - Counterions determine uptake and effects of aluminum in human intestinal and liver cells
N2 - Aluminum (Al) is highly abundant in the biosphere and can occur in different physico-chemical states. It is present in human food and undergoes transitions between dissolved and particulate species during the passage of the gastrointestinal tract. Moreover, in a complex matrix such as food different inorganic and organic counterions can affect the chemical behavior of Al following oral uptake.
In this work, the effects of different counterions, namely chloride, citrate, sulfate, lactate and acetylacetonate, on Al uptake and toxicity in the human intestine are studied. The respective Al salts showed different dissolution behavior in biological media and formed nanoscaled particles correlating in reverse with the amount of their dissolved fraction. The passage through the intestinal barrier was studied using a Caco-2 Transwell® system, showing counterion-dependent variance in cellular uptake and transport. In addition, Al toxicity was investigated using Al species (Al3+, metallic Al0 and oxidic γAl2O3 nanoparticles) and counterions individually or in mixtures on Caco-2 and HepG2 cells. The strongest toxicity was observed using a combination of Al species, depending on solubility, and the lipophilic counterion acetylacetonate. Notably, only the combination of both led to toxicity, while both substances individually did not show toxic effects. A toxification of previously non-toxic Al-species by the presence of acetylacetonate is shown here for the first time. The dependency on the concentration of free Al ions was demonstrated using sodium hydrogen phosphate, which was able to counteract the toxic effects by complexing free Al ions.
These findings, using Al salts as an example for a common food contaminant, underline the importance of a consideration of the chemical properties of human nutrition, especially dissolution and hydrophobicity, which can significantly influence the cellular uptake and effects of xenobiotic substances.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
PY - 2022
DO - https://doi.org/10.1016/j.tiv.2021.105295
VL - 79
SP - 1
EP - 7
PB - Elsevier
AN - OPUS4-54110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dubey, A.
A1 - Hon Keat, C.
A1 - Shvartsman, V.
A1 - Yusenko, Kirill
A1 - Escobar, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Hagemann, U.
A1 - Kovalenko, S.
A1 - Stächler, J.
A1 - Lupascu, D.
T1 - Mono-, Di-, and Tri-valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
N2 - The ferroelectricity of multivalent co-doped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for light photocatalysis exploiting their narrow electronic band gap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono-, di-, or tri-valent cations (Ag+, Ca2+, Dy3+; MDT) co-incorporated BFM NPs are studied under ultrasonication and in acidic conditions. We find that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono- and tri-valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers and larger surface area of NPs. A-site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
KW - Piezoresponse
KW - Bismuth Ferrite
KW - Nanoparticles
KW - Photocatalysis
KW - Ferroelectric
KW - Polarization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557230
DO - https://doi.org/10.1002/adfm.202207105
SN - 1616-301X
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-55723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Bertmer, M.
A1 - Gluth, Gregor
T1 - Sol–gel synthesis and characterization of lithium aluminate (L–A–H) and lithium aluminosilicate (L–A–S–H) gels
N2 - Hydrous lithium aluminosilicate (L–A–S–H) and lithium aluminate (L–A–H) gels are candidate precursors for glass-ceramics and ceramics with potential advantages over conventional processing routes. However, their structure before calcination remained largely unknown, despite the importance of precursor structure on the properties of the resulting materials. In the present study, it is demonstrated that L–A–S–H and L–A–H gels with Li/Al ≤ 1 can be produced via an organic steric entrapment route, while higher Li/Al ratios lead to crystallization of gibbsite or nordstrandite. The composition and the structure of the gels was studied by thermogravimetric analysis, X-ray diffraction, 27Al and 29Si magic-angle spinning nuclear magnetic resonance, and Raman spectroscopy. Aluminium was found to be almost exclusively in six-fold coordination in both the L–A–H and the L–A–S–H gels. Silicon in the L–A–S–H gels was mainly in Q4 sites and to a lesser extent in Q3 sites (four-fold coordination with no Si–O–Al bonds). The results thus indicate that silica-rich and aluminium-rich domains formed in these gels.
KW - Lithium aluminosilicates
KW - Raman spectroscopy
KW - Sol-gel
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558756
DO - https://doi.org/10.1111/ijac.14187
SN - 1546-542X
VL - 19
IS - 6
SP - 3179
EP - 3190
PB - Wiley
AN - OPUS4-55875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glazyrin, Konstantin
A1 - Spektor, Kristina
A1 - Bykov, Maxim
A1 - Dong, Weiwei
A1 - Yu, Ji‐Hun Yu
A1 - Yang, Sangsun Yang
A1 - Lee, Jai‐Sung Lee
A1 - Divinski, Sergiy V.
A1 - Hanfland, Michael
A1 - Yusenko, Kirill
T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
KW - XRD
KW - HIgh entropy,
KW - Cantor
KW - Alloys
KW - Synchrotron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170
DO - https://doi.org/10.1002/advs.202401741
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-60417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ihlenburg, R. B. J.
A1 - Mai, T.
A1 - Thünemann, Andreas
A1 - Baerenwald, R.
A1 - Saalwächter, K.
A1 - Koetz, J.
A1 - Taubert, A.
T1 - Sulfobetaine Hydrogels with a Complex Multilength-Scale Hierarchical Structure
N2 - Hydrogels with a hierarchical structure were prepared from a new highly water-soluble crosslinker N,N,N′,N′-tetramethyl-N,N′-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and from the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The free radical polymerization of the two compounds is rapid and yields near-transparent hydrogels with sizes up to 5 cm in diameter. Rheology shows a clear correlation between the monomer-to-crosslinker ratio and the storage and loss moduli of the hydrogels. Cryo-scanning electron microscopy, low-field nuclear magnetic resonance (NMR) spectroscopy, and small-angle X-ray scattering show that the gels have a hierarchical structure with features spanning the nanometer to the sub-millimeter scale. The NMR study is challenged by the marked inhomogeneity of the gels and the complex chemical structure of the sulfobetaine monomer. NMR spectroscopy shows how these complications can be addressed via a novel fitting approach that considers the mobility gradient along the side chain of methacrylate-based monomers.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Gel
PY - 2021
DO - https://doi.org/10.1021/acs.jpcb.0c10601
SN - 1520-6106
VL - 125
IS - 13
SP - 3398
EP - 3408
PB - American Chemical Society
AN - OPUS4-52403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - PP Nanoplastics Dispersed In Water As Reference Materials
N2 - Plastic debris in micron and nanometer scale pollutes the nature all over the world. The potential dangers of these pollutants remain unpredictable. While risk assessment studies on microplastic are already popular, nanoplastic has not yet reached the same focus of investigation. The reason for this difference is simple: There is a “methodological gap” in the analytics of plastic particles with a diameter smaller than 1 µm. Submicron and nano plastic particles are currently not detectable in environmental matrices. Therefore, it is important for researchers to have a well-characterized nanoplastic material, that serves as a reference for nanoplastic found in nature.
Our aim was to synthesize nanoplastics made from the most common used plastics, starting with polypropylene (PP). We found an easy way to form nanoparticles consisting of PP (nano-PP), adapting and improving the method presented for polystyrene (PS). PP was dispersed to acetone and then transferred to water. No additional surfactant is needed to obtain a dispersion which is stable for more than 35 weeks. The
The success of forming nanoplastics and their size was detected via scattering methods, predominantly dynamic light scattering (DLS). To examine the good stability of the nanoparticles, zeta potential measurements were performed, which revealed zeta potentials of -30 to -40 mV.
This method is repeatable and well suited to produce reference material, as which we propose our prepared particles, based on a homogeneity study, that we performed, following the ISO Guide 35 for reference materials.
T2 - Prague Meeting on Macromolecules 2022
CY - Prag, Czechia
DA - 24.07.2022
KW - Nanoplastic
KW - Reference material
PY - 2022
AN - OPUS4-55961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Aqueous dispersions of polypropylene: towards referencematerials for nanoplastics characterization
N2 - Plastic pollution in the environment is a rising concern for the health of our planet. The plastic litter that pollutes our environment leads to microplastic particles. They can be found (nearly) everywhere. The processes that lead to microplastic can also form nanoplastic particles, which have a size below 1 µm. Because of the small size they can penetrate tissue more easily. Only few risk assessment studies of nanoplastics were carried out so far.
Using polystyrene (PS) nanoparticles to test effects on organisms is easy because it is commercially available. However, this falls a little short, as the polyolefins i.e., polypropylene (PP) and polyethylene (PE), are produced in a larger proportion than PS. Moreover, these plastics are mainly used for disposable products, which means that they also account for a large proportion of plastic waste. Therefore, the percentage of polyolefins in environmental nanoplastic is presumably high. It is important to test the toxicological effects also with nanoplastics made of PP and PE to have more realistic results.
Herein, we present an easy and repeatable method to prepare an aqueous dispersion of polypropylene nanoplastics (nano-PP). They are stabilized electrostatically, resulting in a strongly negative zeta potential of -43 mV (± 2 mV) and making no surfactant necessary to keep the dispersion stable.
The size and the size distribution were determined via Dynamic Light Scattering (DLS) and gives a hydrodynamic diameter of 180.5 nm (± 5.8 nm) and a PDI of 0.084 (± 0.023).
Finally, ca. 480 bottles of the dispersion with a volume of 10 mL each were prepared to serve as a potential reference material for further testing of detection methods or risk assessments.
T2 - International Conference on Microplastic Pollution in the Mediterranean Sea
CY - Neapel, Italy
DA - 25.09.2022
KW - Nanoplastic
PY - 2022
AN - OPUS4-55963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Theiler, Geraldine
A1 - Gradt, Thomas
T1 - Benchmarking of polymer materials for tribological applications in hydrogen
N2 - The focus of this study is to evaluate the influence of hydrogen on the friction and wear behavior of a wide range of polymer materials. Thereby, the tribological performance of filled und unfilled polymers from different suppliers were compared at room temperature in air and hydrogen gas (H2) as well as in liquid hydrogen at -235°C (LH2).
T2 - 23rd International Conference on Wear of Materials
CY - Online meeting
DA - 26.04.2021
KW - Polymers
KW - Hydrogen
KW - Friction
KW - Wear
PY - 2021
AN - OPUS4-52651
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hildebrandt, Jana
T1 - Polypropylene and polyethylene nanoplastics in water
N2 - Considering the huge amount of plastics, that is produced and thrown away all over the world every day, an increasing part of the society became aware of microplastic and its possible impact on the environment. Polymer particles smaller than 1 µm are called nanoplastic. Due to their small size they form a special group within particulate waste. Their high specific surface makes it easier for them to penetrate tissue and pose potential harm. On the other hand, the size and the chemical structure make it difficult to detect and analyze nanoplastics in nature. Furthermore, the concentrations in environmental samples are very low. Therefore, there is a need for a well-characterized nanoplastic material, that serves as a reference for nanoplastic found in nature.
T2 - Tag der Chemie 2021 Uni Potsdam
CY - Online meeting
DA - 06.07.2021
KW - Nanoplastic
PY - 2021
AN - OPUS4-53775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grengg, C.
A1 - Gluth, Gregor
A1 - Mittermayr, F.
A1 - Ukrainczyk, N.
A1 - Bertmer, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Leis, A.
A1 - Dietzel, M.
T1 - Deterioration mechanism of alkali-activated materials in sulfuric acid and the influence of Cu: A micro-to-nano structural, elemental and stable isotopic multi-proxy study
N2 - In this study, a multi-proxy approach combining 29Si, 27Al and 1H MAS-NMR, FEG-EPMA, XANES at the Cu K-edge and XRD analytics with hydrochemical tools such as ICP-OES analyses, oxygen-isotope signatures, and thermodynamic modelling was applied to K-silicate-activated metakaolin specimens - with and without CuSO4·5H2O addition - exposed to sulfuric acid at pH = 2 for 35 days. The results revealed a multistage deterioration mechanism governed by (i) acid diffusion, (ii) leaching of K-A-S-H, (iii) microstructural damage related to precipitation of expansive (K,Ca,Al)-sulfate-hydrate phases (iv) complete dissolution of the K-A-S-H framework, (v) and formation of silica gel in the outermost corroded regions. Copper ions were mainly located in layered spertiniite-chrysocolla-like phases in the as-cured materials. The results demonstrate an overall negative effect of Cu addition on chemical material durability, implying that the reported higher durability of Cu-doped AAM in biocorrosion environments can be best explained by bacteriostatic effects.
KW - Alkali-activated materials
KW - Acid resistance
KW - Microbially induced corrosion
KW - MIC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520567
DO - https://doi.org/10.1016/j.cemconres.2021.106373
SN - 0008-8846
VL - 142
SP - 1
EP - 15
PB - Elsevier
CY - Oxford
AN - OPUS4-52056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Ebell, Gino
A1 - Hlavacek, Petr
A1 - Mietz, Jürgen
T1 - Chloride‐induced steel corrosion in alkali‐activated fly ash mortar: Increased propensity for corrosion initiation at defects
N2 - Chloride contents at the steel–mortar interface that initiate steel corrosion were determined for carbon steel in alkali‐activated fly ash mortar for three different exposure conditions: exposure to 1 M NaCl solution; leaching in deionized water and then exposure to 1 M NaCl solution; and leaching in deionized water, aging in air at 20°C and natural CO2 concentration, and then exposure to 1 M NaCl solution. For comparison, a Portland cement mortar, exposed to 1 M NaCl solution, was studied. The median values of the corrosion‐initiating chloride contents (average over the full length of the rebar) in the alkali‐activated fly ash mortar varied between 0.35 and 1.05 wt% Cl with respect to binder, consistently lower than what was obtained for the Portland cement mortar, but with no clear trend regarding the exposure conditions. For most of the alkali‐activated fly ash mortar specimens, preferential corrosion at the connection between the working electrode and the external measurement setup was observed, while preferential corrosion did not occur for the Portland cement mortar. Scanning electron microscopy and auxiliary experiments in synthetic solutions indicated that this behavior was caused by inhomogeneities at the steel–mortar interface in the alkali‐activated mortar, likely due to its peculiar rheological properties in the fresh state.
KW - Alkali-activated materials
KW - Steel corrosion
KW - Critical chloride content
KW - Steel-concrete interface
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507268
DO - https://doi.org/10.1002/maco.202011541
VL - 71
IS - 5
SP - 749
EP - 758
PB - Wiley-VCH
AN - OPUS4-50726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kulow, Anicó
A1 - Kabelitz, Anke
A1 - Grunewald, C.
A1 - Seidel, R.
A1 - Chapartegui-Arias, Ander
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Emmerling, Franziska
A1 - Beyer, S.
T1 - Observation of early ZIF-8 crystallization stages with X-ray absorption spectroscopy
N2 - The present study investigates early stages of ZIF-8 crystallization up to 5 minutes post mixing of precursor solutions. Dispersive X-ray Absorption Spectroscopy (DXAS) provides a refined understanding of the evolution of the coordination environment during ZIF-8 crystallization. Linear Combination Fiting (LCF) suggests tetrakis(1-methylimidazole)zinc2+ to be a suitable and stable mononuclear structure analogue for some early stage ZIF-8 intermediates. Our results pave the way for more detailed studies on physico-chemical aspects of ZIF-8 crystallization to better control tailoring ZIF-8 materials for specific applications.
KW - In-situ
KW - XANES
KW - ZIF-8
KW - Crystallization
PY - 2020
DO - https://doi.org/10.1039/D0SM01356K
SN - 1744-6848
VL - 17
IS - 2
SP - 331
EP - 334
PB - Royal Scociety of Chemistry
AN - OPUS4-51723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Chen, K.
A1 - Radu, F.
A1 - Weschke, E.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
T1 - Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys
N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2,3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-Surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.
KW - X-ray magnetic circular dichroism (XMCD)
KW - High-entropy alloys
KW - Reverse Monte Carlo
KW - Magnetism
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530668
DO - https://doi.org/10.1007/s12274-021-3704-5
SN - 1998-0124
VL - 15
IS - 6
SP - 4845
EP - 4858
PB - Springer
AN - OPUS4-53066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lutz, C.
A1 - Breuckmann, M.
A1 - Hampel, S.
A1 - Kreyenschmidt, M.
A1 - Ke, X.
A1 - Beuermann, S.
A1 - Schafner, K.
A1 - Turek, T.
A1 - Kunz, U.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Fittschen, U. E. A.
T1 - Characterization of Dimeric Vanadium Uptake and Species in Nafion™ and Novel Membranes from Vanadium Redox Flow Batteries Electrolytes
N2 - A core component of energy storage systems like vanadium redox flow batteries (VRFB) is the polymer electrolyte membrane (PEM). In this work, the frequently used perfluorosulfonic-acid (PFSA) membrane Nafion™ 117 and a novel poly (vinylidene difluoride) (PVDF)-based Membrane are investigated. A well-known problem in VRFBs is the vanadium permeation through the membrane. The consequence of this so-called vanadium crossover is a severe loss of capacity. For a
better understanding of vanadium transport in membranes, the uptake of vanadium ions from electrolytes containing Vdimer(IV–V) and for comparison also V(II), V(III), V(IV), and V(V) by both membranes was studied. UV/VIS spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), total reflection X-ray fluorescence spectroscopy (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and micro X-ray fluorescence spectroscopy (microXRF) were used to determine the vanadium concentrations and the species inside the membrane. The results strongly support that Vdimer(IV–V), a dimer formed from V(IV) and V(V), enters the nanoscopic water-body of Nafion™ 117 as such. This is interesting, because as of now, only the individual ions V(IV) and V(V) were considered to be transported through the membrane. Additionally, it was found that the Vdimer(IV–V) dimer partly dissociates to the individual ions in the novel PVDF-based membrane.
The Vdimer(IV–V) dimer concentration in Nafion™ was determined and compared to those of the other species. After three days of equilibration time, the concentration of the dimer is the lowest compared to the monomeric vanadium species. The concentration of vanadium in terms of the relative uptake λ = n(V)/n(SO3
) are as follows: V(II) [λ = 0.155] > V(III) [λ = 0.137] > V(IV) [λ = 0.124] > V(V) [λ = 0.053] > Vdimer(IV–V) [λ = 0.039]. The results show that the Vdimer(IV–V) dimer Needs to be considered in addition to the other monomeric species to properly describe the transport of vanadium through Nafion™ in VRFBs.
KW - MicroXRF
KW - VRFB
KW - PVDF-based membrane
KW - UV/VIS
KW - XANES
KW - TXRF
KW - ICP-OES
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530676
DO - https://doi.org/10.3390/membranes11080576
VL - 11
IS - 8
SP - 576
PB - MDPI
AN - OPUS4-53067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Vogl, Jochen
A1 - Gluth, Gregor
A1 - Stephan, D.
T1 - Provenancing of cement using elemental analyses and isotope techniques – The state-of-the-art and future perspectives
N2 - With the aim of identifying the origin and the manufacturer of a cement, a reliable procedure that provides unambiguous results is needed. Such procedure could resolve practical issues in damage research, liability issues and forensic investigations. A substantial number of attempts for fingerprinting of building materials, including cement, has already been carried out during the last decades. Most of them were based on concentration analysis of the main elements/components. This review provides an overview of provenance studies of cement and the main approaches commonly used. Provenance studies of cement via isotope techniques are also presented and discussed as representatives of the state-of-the-art in the field. Due to the characteristic properties and the occurrence of carefully selected isotope ratios, unique fingerprints of different kinds of materials can be provided by these methods. This property has largely been explored in various scientific fields such as geo- and cosmochemistry, food forensics, archaeology, geochronology, biomedical studies, and climate change processes. However, the potential of isotope techniques in cement and concrete research for provenance studies has barely been investigated.
Therefore, the review outlines a suitable approach using isotope ratios, which could lead to reliable provenancing of cementitious materials in the future.
KW - Cement
KW - Sr isotopes
KW - Provenance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533762
DO - https://doi.org/10.1039/d1ja00144b
VL - 36
IS - 10
SP - 2030
EP - 2042
PB - The Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-53376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Recent developments of X-ray absorption spectroscopy as analytical tool for biological and biomedical applications
N2 - X-ray absorption spectroscopy (XAS), in its various modalities, has gained exponential attention and applicability in the field of biological and biomedical systems. Particularly in this field, challenges like low concentration of analyte or proneness to radiation damage have certainly settle the basis for further analytical developments, when using X-ray based methods. Low concentration calls for higher sensitivity—by increasing the detection limits (DL); while susceptibility for radiation damage requires shorter measurement times and/or cryogenic sample environment possibilities. This manuscript reviews the latest analytical possibilities that make XAS more and more adequate to investigate biological or biomedical systems in the last 5 years.
KW - Biological & biomedical applications
KW - TXRF-XAS
KW - HERFD-XAS
KW - RXES
KW - Quick-XAS
KW - Dispersive-XAS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531206
DO - https://doi.org/10.1002/xrs.3254
SN - 0049-8246
VL - 51
IS - 3
SP - 1
EP - 10
PB - John Wiley & Sons Ltd
AN - OPUS4-53120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, Alevtina
A1 - Gaertner, Daniel
A1 - Kuzmin, Alexei
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schuck, Goetz
A1 - Zizak, Ivo
A1 - Wilde, Gerhard
A1 - Yusenko, Kirill
A1 - Divinski, Sergiy
T1 - Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi high-entropy alloy
N2 - AbstractMulti-edge extended X-ray absorption fine structure (EXAFS) spectroscopy combined with reverse Monte Carlo (RMC) simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing temperature. Two representative states, namely a high-temperature state, created by annealing at 1373 K, and a low-temperature state, produced by long-term annealing at 993 K, were compared in detail. Specific features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative temperatures. The detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.
KW - Electrical and Electronic Engineering
KW - General Materials Science
KW - Condensed Matter Physics
KW - Atomic and Molecular Physics, and Optics
KW - CCMat
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597687
DO - https://doi.org/10.1007/s12274-024-6443-6
SN - 1998-0124
VL - 17
IS - 6
SP - 5336
EP - 5348
PB - Springer Science and Business Media LLC
AN - OPUS4-59768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunkel, B.
A1 - Kabelitz, Anke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, S.
T1 - Increasing the Efficiency of Optimized V-SBA-15 Catalysts in the Selective Oxidation of Methane to Formaldehyde by Artificial Neural Network Modelling
N2 - The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VOx species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O2, N2 and H2O) onto methane conversion and selectivity towards formaldehyde.
This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kgCH2O∙kgcat∙h−1
KW - Artificial neural network modelling
KW - Selective oxidation
KW - Molecular VOx catalysts
KW - Formaldehyde
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517420
DO - https://doi.org/10.3390/catal10121411
VL - 10
IS - 12
SP - 1411
PB - MDPI
AN - OPUS4-51742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Olivera, Paulo
A1 - Michalchuk, Adam
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Bienert, Ralf
A1 - Torresi, R.
A1 - Camargo, P.
A1 - Emmerling, Franziska
T1 - Tandem X-ray absorption spectroscopy and scattering for in situ time-resolved monitoring of gold nanoparticle mechanosynthesis
N2 - Current time-resolved in situ approaches limit the scope of mechanochemical investigations possible. Here we develop a new, general approach to simultaneously follow the evolution of bulk atomic and electronic structure during a mechanochemical synthesis. This is achieved by coupling two complementary synchrotron-based X-ray methods: X-ray absorption spectroscopy (XAS) and X-ray diffraction. We apply this method to investigate the bottom-up mechanosynthesis of technologically important Au micro and nanoparticles in the presence of three different reducing agents, hydroquinone, sodium citrate, and NaBH4. Moreover, we show how XAS offers new insight into the early stage generation of growth species (e.g. monomers and clusters), which lead to the subsequent formation of nanoparticles. These processes are beyond the detection capabilities of diffraction methods. This combined X-ray approach paves the way to new directions in mechanochemical research of advanced electronic materials.
KW - Mechanochemistry
KW - XANES
KW - X-ray diffraction
KW - Nano particles
PY - 2020
DO - https://doi.org/10.1039/d0cc03862h
SN - 1364-548X
VL - 56
SP - 10329
EP - 10332
PB - Royal Society of Chemistry
AN - OPUS4-51760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Gluth, Gregor
ED - Rossignol, S.
ED - Gluth, Gregor
T1 - Unraveling the hardening mechanism during laser-induced slip casting of lithium aluminate-microsilica slurry
N2 - Additive manufacturing (AM) of alkali-activated materials is a promising method for producing ceramic precursors, construction elements and other parts. A recently introduced AM process is laser-induced slip casting of lithium aluminate/microsilica slurries, which yields parts with excellent mechanical strengths. To clarify the underlying mechanisms, μ-Raman spectroscopy was applied to parts produced by the process, and the dissolution and hydration of lithium aluminate was studied inter alia using conventional and in-situ X-ray diffraction. The results show that significant dissolution of lithium aluminate occurs, particularly at increased temperatures during laser interaction, which leads to an increase of pH and precipitation of an akopovaite-like Li-Al-CO3 layered double hydroxide. The increase of the pH is likely to induce dissolution of the microsilica and possibly formation of a hydrous lithium aluminosilicate gel. These observations explain the strength evolution of the studied parts and can also aid the development and improvement of related AM methods.
KW - Alkali-activated materials
KW - Additive manufacturing
KW - Laser-induced slip casting
KW - Lithium
KW - Layered double hydroxide
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520557
DO - https://doi.org/10.1016/j.oceram.2021.100060
SN - 2666-5395
VL - 5
IS - Special issue: Alkali-activated materials and geopolymers in ceramics and beyond
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-52055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Taylor, J.
A1 - Thakur, S.
A1 - Radu, F.
A1 - Weschke, E.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Xiao, B.
A1 - Savan, A.
A1 - Yusenko, Kirill
A1 - Ludwig, A.
T1 - Local structure and magnetic properties of a nanocrystalline Mn-rich Cantor alloy thin film down to the atomic scale
N2 - The huge atomic heterogeneity of high-entropy materials along with a possibility to unravel the behavior of individual components at the atomic scale suggests a great promise in designing new compositionally complex systems with the desired multi-functionality. Herein, we apply multi-edge X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and X-ray magnetic circular dichroism (XMCD)) to probe the structural, electronic, and magnetic properties of all individual constituents in the single-phase face-centered cubic (fcc)-structured nanocrystalline thin film of Cr20Mn26Fe18Co19Ni17 (at.%) high-entropy alloy on the local scale. The local crystallographic ordering and component-dependent lattice displacements were explored within the reverse Monte Carlo approach applied to EXAFS spectra collected at the K absorption edges of several constituents at room temperature. A homogeneous short-range fcc atomic environment around the absorbers of each type with very similar statistically averaged interatomic distances (2.54–2.55 Å) to their nearest-neighbors and enlarged structural relaxations of Cr atoms were revealed. XANES and XMCD spectra collected at the L2,3 absorption edges of all principal components at low temperature from the oxidized and in situ cleaned surfaces were used to probe the oxidation states, the changes in the electronic structure, and magnetic behavior of all constituents at the surface and in the sub-surface volume of the film. The spin and orbital magnetic moments of Fe, Co, and Ni components were quantitatively evaluated. The presence of magnetic phase transitions and the co-existence of different magnetic phases were uncovered by conventional magnetometry in a broad temperature range.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS),
KW - X-ray magnetic circular dichroism (XMCD),
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578254
DO - https://doi.org/10.1007/s12274-022-5135-3
SN - 1998-0124
SP - 5626
PB - Springer
AN - OPUS4-57825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shasmal, Nilanjana
T1 - Effects of Direct femtosecond laser writing on chloroborosilicate glasses doped with Eu3+/Eu2+ and CdS quantum dots
N2 - Femtosecond (fs) direct laser writing (DLW) is a promising technique for developing nano-inhomogeneous materials with advanced optical properties and for fabricating novel photonic devices such as integrated waveguides, ultrafast optical switches, phase plates, and 3D optical memory. In this study, DLW was applied to chloroborosilicate glasses that were singly and co-doped with Eu and CdS quantum dots (QDs). The glasses were laser-treated within a very narrow range of experimental conditions, resulting in laser-inscribed sites exhibiting enhanced emission, similar to the glass-ceramics crystallized from the as-prepared glass. In the regions crystalized by DLW a significant reduction of Eu3+ to Eu2+ was verified by photoluminescence spectroscopy. However, the characteristics of the emission bands of Eu2+ changed markedly in the laser-treated sites as compared to the emission spectra of the same glass crystallized by heat treatment. A considerable redshift and splitting of the emission band were observed, attributed to changes in the surrounding environment of the rare earth (RE) ions which was, in turn, attributed to an alteration in the coordination number of Ba2 + and/or Eu2+ as a result of the high-power laser treatment. Although there was an issue with homogeneity of the glass in the micro-level, which restricts some of the aspects of the DLW, these findings suggest the potential for structural modifications through laser treatment, which could be harnessed to create new functionalities for advanced optical applications.
T2 - ICG 2025 (27th International Congress on Glass)
CY - Kolkata, India
DA - 20.01.2025
KW - Femtosecond direct laser writing
KW - DLW
KW - CdS quantum dots
KW - Eu/CdS co-doped glass
PY - 2025
AN - OPUS4-65285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Quosdorf, Heike
T1 - Digital object identifier for additively manufactured parts as software package
N2 - A method to uniquely identify samples without printed or handwritten labels is an advantage not just for additively manufactured parts. To kickstart industry use cases, it is also important to provide a ready-made implementation kit. Following an open-science and open-source software approach Germanys Federal Institute for Materials Research and Testing (BAM) seeks to promote digital solutions of ongoing research projects. With this software package a novel method based on microstructural features as identifiers – DOI4AM (digital object identifier for additively manufactured parts) – will be explained alongside its implementation as open-source Python software package. The digital object identifier (DOI) links product data clearly and forgery-proof with real components. Its implementation helps to identify and securely authenticate additively manufactured components during its product life cycle by using characteristic microstructure features - just like a fingerprint. To calculate the DOI fingerprint, a few preprocessing steps need to be performed to detect the uniquely distributed microstructure features that occur during the 3D printing process. A go-through guide shows the preprocessing steps that include CT image capturing, feature segmentation, and data distribution with CSV files. While all steps can be followed along in a Jupyter notebook, the software package includes an application for creating and checking of previously created fingerprints, as well, as a containerized API (application programming interface) service for implementation in existing software platforms or workflows. While data visualization is crucial to understanding the methodology and an essential tool to check for data correctness, an implementation in an industry use case needs to be slim and resource efficient. Therefor the software’s API can be used as an independent service. The project's industry partner proofs its first successful implementation in their digital product passport web solution PASS-X.
T2 - AI MSE 2025
CY - Bochum, Germany
DA - 18.11.2025
KW - Authentication
KW - Unique identification
KW - Digital object identifier
KW - Additive Manufacturing
KW - Non-destructive testing
KW - Open Source Software
KW - Digital fingerprint
KW - X-ray Computed Tomography
KW - Open Science
PY - 2025
AN - OPUS4-65293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fortes Martin, R.
A1 - Thünemann, Andreas
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Koetz, J.
T1 - From Nanoparticle Heteroclusters to Filament Networks by Self-Assembly at the Water–Oil Interface of Reverse Microemulsions
N2 - Surface self-assembly of spherical nanoparticles of sizes below 10 nm into hierarchical heterostructures is under arising development despite the inherent difficulties of obtaining complex ordering patterns on a larger scale. Due to template-mediated interactions between oil-dispersible superparamagnetic nanoparticles (MNPs) and polyethylenimine-stabilized gold nanoparticles (Au(PEI)NPs) at the water–oil interface of microemulsions, complex nanostructured films can be formed. Characterization of the reverse microemulsion phase by UV–vis absorption revealed the formation of heteroclusters from Winsor type II phases (WPII) using Aerosol-OT (AOT) as the surfactant. SAXS measurements verify the mechanism of initial nanoparticle clustering in defined dimensions. XPS suggested an influence of AOT at the MNP surface. Further, cryo-SEM and TEM visualization demonstrated the elongation of the reverse microemulsions into cylindrical, wormlike structures, which subsequently build up larger nanoparticle superstructure arrangements. Such WPII phases are thus proven to be a new form of soft template, mediating the self-assembly of different nanoparticles in hierarchical network-like filaments over a substrate during solvent evaporation.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Nano structure
PY - 2021
DO - https://doi.org/10.1021/acs.langmuir.1c01348
VL - 37
IS - 29
SP - 8876
EP - 8885
PB - American Chemical Society
AN - OPUS4-53034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tu, Z.
A1 - Donskyi, Ievgen
A1 - Qiao, H.
A1 - Zhu, Z.
A1 - Unger, Wolfgang
A1 - Hackenberger, C. P. R.
A1 - Chen, W.
A1 - Adeli, M.
A1 - Haag, R.
T1 - Graphene Oxide-Cyclic R10 Peptide Nuclear Translocation Nanoplatforms for the Surmounting of Multiple-Drug Resistance
N2 - Multidrug resistance resulting from a variety of defensive pathways in Cancer has become a global concern with a considerable impact on the mortality associated with the failure of traditional chemotherapy. Therefore, further research and new therapies are required to overcome this challenge. In this work, a cyclic R10 peptide (cR10) is conjugated to polyglycerol-covered nanographene oxide to engineer a nanoplatform for the surmounting of multidrug resistance. The nuclear translocation of the nanoplatform, facilitated by cR10 peptide, and subsequently, a laser-triggered release of the loaded doxorubicin result in efficient anticancer activity confirmed by both in vitro and in vivo experiments. The synthesized nanoplatform with a combination of different features, including active nucleus-targeting, highloading capacity, controlled release of cargo, and photothermal property, provides a new strategy for circumventing multidrug resistant cancers.
KW - Graphen Oxide
KW - Nanoplatform
KW - Cancer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510061
DO - https://doi.org/10.1002/adfm.202000933
VL - 30
IS - 35
SP - 2000933
PB - Wiley VCH
AN - OPUS4-51006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kulka, M.W.
A1 - Nie, C.
A1 - Nickl, P.
A1 - Kerkhoff, Y.
A1 - Garg, A.
A1 - Salz, D.
A1 - Radnik, Jörg
A1 - Grunwald, I.
A1 - Haag, R.
T1 - Surface-Initiated Grafting of Dendritic Polyglycerol from Mussel-Inspired Adhesion-Layers for the Creation of Cell-Repelling Coatings
N2 - Biofouling is a major challenge in the application of textiles, biosensors, and biomedical implants. In the current work, a straightforward method for the solvent-free polymerization of antifouling dendritic polyglycerol (dPG) from mussel-inspired dendritic polyglycerol (MI-dPG) coatings on hydrophilic titanium dioxide (TiO2) and hydrophobic polydimethylsiloxane (PDMS) is reported. Surface characterization is performed by static water contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Significant lower CA values are obtained after dPG grafting from MI-dPG-coated TiO2 and MI-dPG coated PDMS. Furthermore, XPS shows a time-dependent increase of the CO bond content upon dPG grafting from MI-dPG-coated TiO2 and MI-dPG-coated PDMS. Analysis of the surface morphology by SEM shows a clear time-dependent increase in the surface roughness upon dPG grafting from MI-dPG-coated TiO2 and MIdPG-coated PDMS. When the viability of two adhesive cell types is studied via LIVE/DEAD staining, a strong reduction in the cell density is observed after the dPG grafting from MI-dPG-coated TiO2 and MI-dPG-coated PDMS (a decrease of >95% in all cases). The combined results show that biocompatible but highly cell-repelling surfaces are efficiently constructed via the grafting of dPG from MI-dPG-coated TiO2 and MI-dPG-coated PDMS.
KW - Repelling surface coatings
KW - Dendritic polyglycerol
KW - Mussel-inspired adhesives
KW - Surface-initated grafting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516590
DO - https://doi.org/10.1002/admi.202000931
SN - 2196-7350
VL - 7
IS - 24
SP - 931
PB - Wiley VCH
AN - OPUS4-51659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigert, Florian
A1 - Müller, A.
A1 - Häusler, I.
A1 - Geißler, Daniel
A1 - Skroblin, D.
A1 - Unger, Wolfgang
A1 - Radnik, Jörg
A1 - Resch-Genger, Ute
T1 - Combining HR‑TEM and XPS to elucidate the core–shell structure of ultrabright CdSe/CdS semiconductor quantum dots
N2 - Controlling thickness and tightness of surface passivation shells is crucial for many applications of core–shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the applicationrelevant functionality like a high photoluminescence (PL) quantum yield, calling for a whole nanoobject approach. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. In addition to demonstrating the potential of this novel whole nanoobject approach for determining architectures of small nanoparticles, the presented results also highlight challenges faced by different sizing and structural analysis methods and method-inherent uncertainties.
KW - Photoluminescence
KW - Single particle
KW - Microscopy
KW - Particle architecture
KW - Thickness
KW - SAXS
KW - Shell
KW - XPS
KW - TEM
KW - Semiconductor
KW - Quantum dot
KW - Photophysics
KW - Quantum yield
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517911
DO - https://doi.org/10.1038/s41598-020-77530-z
VL - 10
IS - 1
SP - 20712
PB - Springer Nature
AN - OPUS4-51791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Krahl, T.
A1 - Radnik, Jörg
A1 - Wagner, Andreas
A1 - Werner, W. S. M.
A1 - Ritter, B.
A1 - Kemnitz, E.
A1 - Unger, Wolfgang
T1 - Chemical in-depth analysis of (Ca/Sr)F2 core–shell like nanoparticles by X-ray photoelectron spectroscopy with tunable excitation energy
N2 - The fluorolytic sol–gel synthesis is applied with the intention to obtain two different types of core–shell nanoparticles, namely, SrF2–CaF2 and CaF2–SrF2. In two separate fluorination steps for core and shell formation, the corresponding metal lactates are reacted with anhydrous HF in ethylene glycol. Scanning transmission electron microscopy (STEM) and dynamic light scattering (DLS) confirm the formation of particles with mean dimensions between 6.4 and 11.5 nm. The overall chemical composition of the particles during the different reaction steps is monitored by quantitative Al Kα excitation X-ray photoelectron spectroscopy (XPS). Here, the formation of stoichiometric metal fluorides (MF2) is confirmed, both for the core and the final core–shell particles. Furthermore, an in-depth analysis by synchrotron radiation XPS (SR-XPS) with tunable excitation energy is performed to confirm the core–Shell character of the nanoparticles. Additionally, Ca2p/Sr3d XPS intensity ratio in-Depth profiles are simulated using the software Simulation of Electron Spectra for Surface Analysis (SESSA). In principle, core–shell like particle morphologies are formed but without a sharp interface between calcium and strontium containing phases.
Surprisingly, the in-depth chemical distribution of the two types of nanoparticles is equal within the error of the experiment. Both comprise a SrF2-rich core domain and CaF2-rich shell domain with an intermixing zone between them. Consequently, the internal morphology of the final nanoparticles seems to be independent from the synthesis chronology.
KW - Metal fluorides
KW - Sol-gel synthesis
KW - Synchrotron radiation
KW - X-ray photoelectron spectroscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522284
DO - https://doi.org/10.1002/sia.6937
SN - 0142-2421
VL - 53
IS - 5
SP - 494
EP - 508
PB - Wiley VCH
AN - OPUS4-52228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Müller, Anja
A1 - Radnik, Jörg
A1 - Hachenberger, Y.
A1 - Jungnickel, H.
A1 - Laue, P.
A1 - Luch, A.
A1 - Tentschert, J.
T1 - Preparation of Nanoparticles for ToF-SIMS and XPS Analysis
N2 - Nanoparticles have gained increasing attention in recent years due to their potential and application in different fields including medicine, cosmetics, chemistry, and their potential to enable advanced materials. To effectively understand and regulate the physico-chemical properties and potential adverse effects of nanoparticles, validated measurement procedures for the various properties of nanoparticles need to be developed. While procedures for measuring nanoparticle size and size Distribution are already established, standardized methods for analysis of their surface chemistry are not yet in place, although the influence of the surface chemistry on nanoparticle properties is undisputed. In particular, storage and preparation of nanoparticles for surface analysis strongly influences the analytical results from various methods, and in order to obtain consistent results, sample preparation must be both optimized and standardized. In this contribution, we present, in detail, some standard procedures for preparing nanoparticles for surface analytics. In principle, nanoparticles can be deposited on a suitable substrate from suspension or as a powder. Silicon (Si) Wafers are commonly used as substrate, however, their cleaning is critical to the process. For sample preparation from suspension, we will discuss drop-casting and spin-coating, where not only the cleanliness of the substrate and purity of the suspension but also its concentration play important roles for the success of the preparation methodology.
For nanoparticles with sensitive ligand shells or coatings, deposition as powders is more suitable, although this method requires particular care in fixing the sample.
KW - Titania nanoparticles
KW - X-ray photoelectron spectroscopy
KW - Secondary ion mass spectrometry
KW - Surface chemisttry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520103
UR - https://www.jove.com/video/61758
DO - https://doi.org/10.3791/61758
VL - 163
SP - e61758
AN - OPUS4-52010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Donskyi, Ievgen
A1 - Nie, C.
A1 - Ludwig, K.
A1 - Trimpert, J.
A1 - Ahmed, R.
A1 - Quaas, E.
A1 - Achazi, K.
A1 - Radnik, Jörg
A1 - Adeli, M.
A1 - Haag, R.
A1 - Osterrieder, K.
T1 - Graphene Sheets with Defined Dual Functionalities for the Strong SARS-CoV-2 Interactions
N2 - Search of new strategies for the inhibition of respiratory viruses is one of the urgent health challenges worldwide, as most of the current therapeutic agents and treatments are inefficient. Severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) has caused a pandemic and has taken lives of approximately two Million people to date. Even though various vaccines are currently under development, virus, and especially its spike glycoprotein can mutate, which highlights a Need for a broad-spectrum inhibitor. In this work, inhibition of SARS-CoV-2 by graphene platforms with precise dual sulfate/alkyl functionalities is investigated. A series of graphene derivatives with different lengths of aliphatic chains is synthesized and is investigated for their ability to inhibit SARS-CoV-2 and feline coronavirus.
Graphene derivatives with long alkyl chains (>C9) inhibit coronavirus replication by virtue of disrupting viral envelope. The ability of these graphene platforms to rupture viruses is visualized by atomic force microscopy and cryogenic electron microscopy. A large concentration window (10 to 100-fold) where graphene platforms display strongly antiviral activity against native SARS-CoV-2 without significant toxicity against human cells is found. In this concentration range, the synthesized graphene platforms inhibit the infection of enveloped viruses efficiently, opening new therapeutic and metaphylactic avenues against SARS-CoV-2.
KW - Graphene
KW - Graphene-based polyglycerol sulfates
KW - SARS-CoV2 inhibitor
KW - Virucidality
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520858
DO - https://doi.org/10.1002/smll.202007091
VL - 17
IS - 11
SP - 7091
PB - Wiley VCH
AN - OPUS4-52085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Knigge, Xenia
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Cant, D.J.H.
A1 - Shard, A.G.
A1 - Clifford, C.A.
T1 - Composition, thickness, and homogeneity of the coating of core–shell nanoparticles—possibilities, limits, and challenges of X-ray photoelectron spectroscopy
N2 - Core–shell nanoparticles have attracted much attention in recent years due to their unique properties and their increasing importance in many technological and consumer products. However, the chemistry of nanoparticles is still rarely investigated in comparison to their size and morphology. In this review, the possibilities, limits, and challenges of X-ray photoelectron spectroscopy (XPS) for obtaining more insights into the composition, thickness, and homogeneity of nanoparticle coatings are discussed with four examples: CdSe/CdS quantum dots with a thick coating and a small core; NaYF4-based upconverting nanoparticles with a large Yb-doped core and a thin Er-doped coating; and two types of polymer nanoparticles with a poly(tetrafluoroethylene) core with either a poly(methyl methacrylate) or polystyrene coating. Different approaches for calculating the thickness of the coating are presented, like a simple numerical modelling or a more complex simulation of the photoelectron peaks. Additionally, modelling of the XPS background for the investigation of coating is discussed. Furthermore, the new possibilities to measure with varying excitation energies or with hard-energy X-ray sources (hard-energy X-ray photoelectron spectroscopy) are described. A discussion about the sources of uncertainty for the determination of the thickness of the coating completes this review.
KW - X-ray spectroscopy
KW - Nanoparticles
KW - Spectroscopy / Instrumentation
KW - Spectroscopy / Theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548305
DO - https://doi.org/10.1007/s00216-022-04057-9
VL - 414
IS - 15
SP - 4331
EP - 4345
PB - SpringerNature
AN - OPUS4-54830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Was Sie schon immer über Chunky-Graphit wissen w(s)ollten, aber bisher nicht zu fragen wagten
N2 - Duktile Gusseisenwerkstoffe mit Kugelgraphit (GJS) haben ein erhebliches technisches Potenzial und sind von wirtschaftlicher Bedeutung. Nicht zuletzt daher ist es ökonomisch sinnvoll, gesellschaftlich nachhaltig und wissenschaftlich interessant, ihren Herstellungsprozess zu optimieren. Eine maßgebliche Rolle kommt hierbei der Vermeidung von Qualitätsabweichungen in Form von Gefügefehlern zu. Dieser Beitrag befasst sich mit der – leider vielfach nicht richtig oder zu wenig verstandenen, aber insbesondere bei kostenintensi-ven dickwandigen Gussteilen relevanten - Graphitentartung Chunky-Graphit (CG).
Die metallurgischen Ursachen von CG werden noch immer kontrovers diskutiert. Eine allgemein akzeptierte Theorie zur Bildung und dem Wachstumsmechanismus von CG existiert nicht, in der Gießereipraxis wird gleichwohl eine Fülle spezifischer technologischer Abhilfemaßnahmen praktiziert [1].
Der Schwerpunkt dieses Beitrages liegt jedoch nicht auf der metallurgischen Seite, sondern auf der Beschrei-bung der spezifischen Morphologie von CG (Bild 1), dessen Detektion im Werkstoff bzw. Bauteil sowie den Auswirkungen von CG auf die Werkstoffeigenschaften. Detailliert werden Möglichkeiten und Grenzen zer-störungsfreier und zerstörender Untersuchungsverfahren zur Identifikation und Quantifizierung von CG aufgezeigt. Ausgehend von der charakteristischen Morphologie von CG wird dessen Einfluss auf das Ver-formungs- und Bruchverhalten von GJS behandelt. Beispielhaft werden dabei die Eigenschaften Festigkeit, Verformbarkeit, das Risswachstumsverhalten und die Bruchzähigkeit diskutiert und Schlussfolgerungen für die Bewertung von mit CG behafteten GJS-Bauteilen abgeleitet.
T2 - Ledebur-Kolloquium 2023
CY - Freiberg, Germany
DA - 26.10.2023
KW - Gusseisen mit Kugelgraphit GJS
KW - Chunky-Graphit
KW - Graphitentartung
KW - Duktiles Gusseisen
PY - 2023
AN - OPUS4-58636
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Investigation of the Master Curve Concept for Ferritic Ductile Cast Iron (DCI)
N2 - Based on state-of-the-art research and regulations, the application of the fracture mechanics master curve (MC) concept to ferritic ductile cast iron (DCI) is being investigated in a recently started German joint research project between BAM Berlin and MPA Stuttgart. This paper outlines the research approach and the planned investigations and provides first results.
According to the IAEA guidelines SSG 26, the safety assessment of DCI containers for transport as well as interim and final storage of radioactive materials is based on the fracture mechanics criterion of general crack initiation exclusion. Within this context, the focus of the current research project is on the further development of brittle fracture safety assessment methods under dynamic loading conditions. Within fracture mechanics safety assessments for steels in nuclear technology, the probabilistic MC concept according to ASTM E1921 is currently used for quasi-static loading conditions as a supplement to the established deterministic ASME reference curve concept. The MC concept allows for an effective statistical consideration of the scatter of the material toughness in the transition regime. Furthermore, the MC can also be used for elevated loading rates as they occur in accident or crash scenarios. However, for DCI, a systematic review of potential modifications to the MC assumptions and procedure according to ASTM E1921 and an associated validation are still lacking. Therefore, a corresponding methodology shall be established to determine and assess dynamic fracture toughness values of DCI in the ductile-to-brittle transition regime, using samples extracted from a component.
For the experimental program, a DCI material was produced as it is generally used for transport and storage containers. A basic mechanical-technological material characterization consisting of tensile, Charpy, and Pellini tests is planned. A comprehensive fracture mechanics test program was compiled covering dynamic testing of DC(T)9, C(T)25, C(T)50, SE(B)10, SE(B)25, and SE(B)140 specimens. Moreover, numerical analyses of different specimen geometries and test setups are planned to investigate the influences of stress triaxiality and loading rate. Throughout the experimental program, the microstructure-property relationship will be investigated based on quantitative metallographic and fractographic analyses. Finally, different MC assessment strategies will be considered, and modifications will be made if necessary.
T2 - PATRAM22 Conference
CY - Juans-les-Pins, France
DA - 11.06.2023
KW - Dynamic Fracture Toughness
KW - Ductile Cast Iron
KW - Master Curve Method
PY - 2023
AN - OPUS4-57766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Page, T.M.
A1 - Nie, C.
A1 - Neander, L.
A1 - Povolotsky, T.L.
A1 - Sahoo, A.K.
A1 - Nickl, Philip
A1 - Adler, J.M.
A1 - Bawadkji, O.
A1 - Radnik, Jörg
A1 - Achazi, K.
A1 - Ludwig, K.
A1 - Lauster, D.
A1 - Netz, R.R.
A1 - Trimpert, J.
A1 - Kaufer, B.
A1 - Haag, R.
A1 - Donskyi, Ievgen
T1 - Functionalized Fullerene for Inhibition of SARS-CoV-2 Variants
N2 - As virus outbreaks continue to pose a challenge, a nonspecific viral inhibitor can provide significant benefits, especially against respiratory viruses. Polyglycerol sulfates recently emerge as promising agents that mediate interactions between cells and viruses through electrostatics, leading to virus inhibition.
Similarly, hydrophobic C60 fullerene can prevent virus infection via interactions with hydrophobic cavities of surface proteins. Here, two strategies are combined to inhibit infection of SARS-CoV-2 variants in vitro. Effective inhibitory concentrations in the millimolar range highlight the significance of bare fullerene’s hydrophobic moiety and electrostatic interactions of polysulfates with surface proteins of SARS-CoV-2. Furthermore, microscale thermophoresis measurements support that fullerene linear polyglycerol sulfates interact with the SARS-CoV-2 virus via its spike protein, and highlight importance of electrostatic interactions within it. All-atom molecular dynamics simulations reveal that the fullerene binding site is situated close to the receptor binding domain, within 4 nm of polyglycerol sulfate binding sites, feasibly allowing both portions of the material to interact simultaneously.
KW - Covalent functionalization
KW - Fullerene
KW - SARS-CoV 2
KW - Sulfated materials
KW - Virus inhibition
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568672
DO - https://doi.org/10.1002/smll.202206154
SN - 1613-6810
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-56867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bawadkji, O.
A1 - Cherri, M.
A1 - Schäfer, A.
A1 - Herziger, S.
A1 - Nickl, Philip
A1 - Achazi, K.
A1 - Donskyi, Ievgen
A1 - Adeli, M.
A1 - Haag, R.
T1 - One-pot covalent functionalization of 2D black phosphorus by anionic ring opening polymerization
N2 - In this work, a one-pot approach for the covalent functionalization of few-layer black phosphorus (BP) by anionic ring opening polymerization of glycidol to obtain multifunctional BP-polyglycerol (BP-PG) with high amphiphilicity for near-infrared-responsive drug delivery and biocompatibility is reported. Straightforward synthesis in combination with exceptional biological and physicochemical properties designates functionalized BP-PG as a promising candidate for a broad range of biomedical applications.
KW - 2D nanomaterial
KW - Amphiphilicity
KW - Black phosphorus
KW - Hyperbranched
KW - Polyglycerol
KW - Water dispersibility
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568833
DO - https://doi.org/10.1002/admi.202201245
SN - 2196-7350
VL - 9
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - 1,3-Dimethyl-imidazolium dimethyl phosphate ([MMIM]+[DMP]−) analyzed by XPS and HAXPES
N2 - The ionic liquid 1,3-dimethyl-imidazolium-dimethylphosphate ([MMIM]+[DMP]−) was analyzed using (hard) x-ray photoelectron spectroscopy.
Here, XPS and HAXPES spectra are shown in comparison. For the acquisition of the XPS spectra, monochromatic Al Kα radiation at 1486.6 eV was used, while for the acquisition of the HAXPES spectra, monochromatic Cr Kα radiation at 5414.8 eV was applied. Here, survey scans and high-resolution spectra of P 2p, P 2s, C 1s, O 1s, and N 1s for both methods and P 1s, P KL2,3L2,3, and P KL1L2,3 for HAXPES are shown.
KW - C7H15N2O4P
KW - [MMIM]+[DMP]−
KW - Lonic liquid
KW - Hard x-ray photoelectron spectroscopy
KW - HAXPES
KW - XPS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571604
DO - https://doi.org/10.1116/6.0002297
VL - 30
IS - 1
SP - 1
EP - 20
PB - AIP Publishing
AN - OPUS4-57160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Z.
A1 - Perez, J. P. H.
A1 - Smales, Glen Jacob
A1 - Blukis, R.
A1 - Pauw, Brian Richard
A1 - Stammeier, J. A.
A1 - Radnik, Jörg
A1 - Smith, A. J.
A1 - Benning, L. G.
T1 - Impact of organic phosphates on the structure and composition of short-range ordered iron nanophases
N2 - Organic phosphates (OP) are important nutrient components for living cells in natural environments, where they readily interact with ubiquitous iron phases such as hydrous ferric oxide, ferrihydrite (FHY). FHY partakes in many key bio(geo)chemical reactions including iron-mediated carbon storage in soils, or iron-storage in living organisms. However, it is still unknown how OP affects the formation, structure and properties of FHY. Here, we document how β-glycerophosphate (GP), a model OP ligand, affects the structure and properties of GP–FHY nanoparticles synthesized by coprecipitation at variable nominal molar P/Fe ratios (0.01 to 0.5). All GP–FHY precipitates were characterized by a maximum solid P/Fe ratio of 0.22, irrespective of the nominal P/Fe ratio. With increasing nominal P/Fe ratio, the specific surface area of the GP–FHY precipitates decreased sharply from 290 to 3 m2 g−1, accompanied by the collapse of their pore structure. The Fe–P local bonding environment gradually transitioned from a bidentate binuclear geometry at low P/Fe ratios to monodentate mononuclear geometry at high P/Fe ratios. This transition was accompanied by a decrease in coordination number of edge-sharing Fe polyhedra, and the loss of the corner-sharing Fe polyhedra. We show that Fe(III) polymerization is impeded by GP, and that the GP–FHY structure is highly dependent on the P/Fe ratio. We discuss the role that natural OP-bearing Fe(III) nanophases have in biogeochemical reactions between Fe–P and C species in aquatic systems.
KW - Organic phosphates
KW - Iron nanophases
KW - Scattering
KW - Diffraction
KW - Nanomaterials
KW - Coprecipitation
KW - Carbon storage
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599399
DO - https://doi.org/10.1039/d3na01045g
SN - 2516-0230
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-59939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Opitz, R.
A1 - Ghoreishi, N.
A1 - Plate, K.
A1 - Barnes, J.-P.
A1 - Bellew, A.
A1 - Bellu, A.
A1 - Ceccone, G.
A1 - de Vito, E.
A1 - Delcorte, A.
A1 - Franquet, A.
A1 - Fumageli, F.
A1 - Gilliland, D.
A1 - Jungnickel, H.
A1 - Lee, T.G.
A1 - Poleunis, C.
A1 - Rading, D.
A1 - Shon, H.K.
A1 - Spampinato, V.
A1 - Son, J.G.
A1 - Wang, F.
A1 - Wang, Y.-C. A.
A1 - Zhao, Y.
A1 - Roloff, A.
A1 - Tentschert, J.
A1 - Radnik, Jörg
T1 - VAMAS TWA2 interlaboratory comparison: Surface analysis of TiO2 nanoparticles using ToF-SIMS
N2 - Due to the extremely high specific surface area of nanoparticles and corresponding potential for adsorption, the results of surface analysis can be highly dependent on the history of the particles, particularly regarding sample preparation and storage. The sample preparation method has, therefore, the potential to have a significant influence on the results. This report describes an interlaboratory comparison (ILC) with the aim of assessing which sample preparation methods for ToF-SIMS analysis of nanoparticles provided the most intra- and interlaboratory consistency and the least amount of sample contamination. The BAM reference material BAM-P110 (TiO2 nanoparticles with a mean Feret diameter of 19 nm) was used as a sample representing typical nanoparticles. A total of 11 participants returned ToF-SIMS data,in positive and (optionally) negative polarity, using sample preparation methods of “stick-and-go” as well as optionally “drop-dry” and “spin-coat.” The results showed that the largest sources of variation within the entire data set were caused by adventitious hydrocarbon contamination or insufficient sample coverage, with the spin-coating protocol applied in this ILC showing a tendency toward insufficient sample coverage; the sample preparation method or the participant had a lesser influence on results.
KW - Secondary Ion Mass Spectrometry
KW - VMAAS
KW - Titania
KW - Interlaboratory comparison
KW - Reproducibility
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582290
DO - https://doi.org/10.1116/6.0002814
SN - 0734-2101
VL - 41
IS - 5
SP - 053210-1
EP - 053210-13
PB - AIP (American Institute of Physics)
AN - OPUS4-58229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hirahara, Kenta
A1 - Bonse, Jörn
A1 - Krüger, Jörg
A1 - Weise, Matthias
A1 - Ermilova, Elena
A1 - Schusterbauer, Robert
A1 - Unterreiner, Andreas-Neil
A1 - Hertwig, Andreas
T1 - A multi-method study of femtosecond laser modification and ablation of amorphous hydrogenated carbon coatings
N2 - e present a study on femtosecond laser treatment of amorphous hydrogen-containing carbon coatings (a-C:H). The coatings were deposited on silicon wafers by a plasma-assisted chemical vapour deposition (PA-CVD), resulting in two different types of material with distinct properties (referred to as “absorbing” and “semi-transparent” coatings in the following).
The samples were laser-treated with single fs-laser pulses (800 nm center wavelength, 35 fs pulse duration) in the ablative regime. Through a multi-method approach using topometry, Raman spectroscopy, and spectroscopic imaging ellipsometry, we can identify zones and thresholds of diferent fuence dependent efects and have access to the local dielectric function.
The two coating materials react signifcantly diferent upon laser treatment. We determined the (non-ablative) modifcation threshold fuence for the absorbing coating as 3.6 × 10−2 Jcm−2 and its ablation threshold as 0.22 Jcm−2. The semi-transparent coating does not show such a low-fuence modifcation but exhibits a characteristic interference-based intra-flm ablation mechanism with two distinguishable ablation thresholds at 0.25 and 0.28 Jcm−2, respectively. The combination of tailored layer materials and correlative imaging spectroscopic methods delivers new insights into the behaviour of materials when treated with ultrashort-pulse laser radiation
KW - Amorphous Hydrogenated Carbon Coatings
KW - Correlative Imaging Measurement Techniques
KW - Hybrid Metrology
KW - Imaging Spectroscopy
KW - Spectroscopic Ellipsometry
KW - Ultra-short Pulse Laser Materials Processing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617829
DO - https://doi.org/10.1007/s00339-024-07980-z
VL - 130
IS - 12
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-61782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Broichert, C.
A1 - Klingenhof, M.
A1 - Frisch, M.
A1 - Dresp, S.
A1 - Kubo, N.M.
A1 - Artz, J.
A1 - Radnik, Jörg
A1 - Palkovits, S.
A1 - Beine, A.K.
A1 - Strasser, P.
A1 - Palkovits, R.
T1 - Particle size-controlled synthesis of highperformance MnCo-based materials for alkaline OER at fluctuating potentials
N2 - For the large-scale generation of hydrogen via water electrolysis the design of long term stable and active catalysts for the oxygen evolution reaction (OER) remains a key challenge. Most catalysts suffer from severe structural corrosion that becomes even more pronounced at fluctuating potentials. Herein, MnCo based cubic particles were prepared via a hydrothermal approach, in which the edge length of the micron-sized particles can be controlled by changing the pH value of the precursor solution. The cubes are composed of varying amounts of MnCo2O4, CoCO3 and a mixed (Mn/Co)CO3 phase. Structure–activity relationships were deduced revealing a volcano-type behavior for the intrinsic OER activity and fraction of spinel oxide phase.
A low overpotential of 0.37 V at 10 mA cm−2 and a stability of more than 25 h was achieved in 1.0 M KOH using a rotating disc electrode (RDE) setup. The best performing catalyst material was successfully tested under dynamic process conditions for 9.5 h and shows a superior catalytic activity as anode for the Overall water splitting in an electrolyser setup in 1.0 M KOH at 333 K compared to a reference NiCo-spinel catalyst.
KW - Water electrolysis
KW - Oxygen evolution reaction
KW - Structure activity relationships
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536050
DO - https://doi.org/10.1039/d1cy00905b
SN - 2044-4753
VL - 11
IS - 12
SP - 7278
EP - 7286
PB - Royal Society of Chemistry
AN - OPUS4-53605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaki, Mohammad
T1 - Nano-And Advanced Materials Synthesis In A Self-Driving Lab (SDL)
N2 - Nano- and advanced materials are recognized as key enabling technologies of the 21st century, offering exceptional potential to drive innovation and tackle pressing challenges in materials science. To fully realize this potential, it is essential to develop and improve tools that accelerate their design, development, and optimization.
Recognizing this pressing need, we present a Self-Driving Lab (SDL) that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nanomaterials, with automated characterization and data analysis, for a complete and reliable nanomaterial synthesis workflow. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. The system also exhibits modularity, impressive adaptability in terms of reactions scales and incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence) of the nanomaterials, along with automating data analysis of at-line or off-line characterization techniques such as electron microscopy image analyses.
Automated characterization and data analysis is complemented by a machine learning–driven feedback loop employing active learning algorithms (e.g., Bayesian optimization, artificial neural networks, and downhill simplex methods) to iteratively suggest new experimental parameters toward desired material properties.
Therefore, the excellent reproducibility for material syntheses when run on the SDL platform multiple times, the material agnostic behavior, the adaptability, and modularity, underscore the SDL’s reliability and potential as a transformative tool for advancing the development and applications of nano- and advanced materials, offering solutions for a sustainable future.
T2 - Gordon Research Seminar and Conference, Multifunctional Materials and Structures-conference
CY - Ventura, CA, USA
DA - 24.01.2026
KW - Self-Driving Laboratories
KW - Materials Acceleration Platforms
KW - Nanomaterials
PY - 2026
AN - OPUS4-65597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kumar, Sourabh
T1 - Grain Boundary Transformation Induced by Boron Segregation
N2 - The segregation of solute atoms at grain boundaries (GBs) plays a critical role in defining the mechanical properties of materials, including corrosion resistance and fracture toughness. This study investigates the structural transformations induced by minimal boron concentrations at Σ13 GBs in ferrite thin films synthesized. Two sample protocols were examined: one with carbon as the sole solute and the other with carbon and boron co-segregation. To understand the thermodynamics of such phases, we employed ab initio calculations to meticulously examine the competing Σ13 GB phases that coexist in the presence of defects and stacking faults. Building on our findings regarding these competing GB phases, we analyzed the energetic aspects of solute segregation at the GB interface. Furthermore, we constructed a defect phase diagram to gain insights into the influence of Boron concentration on the evolution of GB structure. We reveal that boron segregation transforms the GB structure from flat to zigzag trigonal prisms by forming new chemical bonds, ultimately enhancing bonding strength between boron and iron atoms by 5%. This transformation doubles steel's resistance to fracture and provides valuable insights into the thermodynamic and energetic aspects of solute-driven GB phase evolution. These findings contribute to developing innovative strategies for designing high-performance steel with enhanced mechanical integrity and durability.
T2 - DPG 2025 Regensburg
CY - Regensburg, Germany
DA - 16.03.2025
KW - Defect Phases
KW - Grain Boundary
KW - Steel
PY - 2025
AN - OPUS4-65580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zaki, Mohammad
T1 - Nano- and Advanced Materials Synthesis in a Self-Driving Lab
N2 - Nano- and advanced materials are recognized as key enabling technologies of the 21st century, offering exceptional potential to drive innovation and tackle pressing challenges in materials science [1]. To fully realize this potential, it is essential to develop and improve tools that accelerate their design, development, and optimization.
Recognizing this pressing need, we present a Self-Driving Lab (SDL) [2] that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nanomaterials, with automated characterization and data analysis, for a complete and reliable nanomaterial synthesis workflow. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. The system also exhibits modularity, impressive adaptability in terms of reactions scales and incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence) of the nanomaterials, along with automating data analysis of at-line or off-line characterization techniques such as electron microscopy image analyses [3].
Automated characterization and data analysis is complemented by a machine learning–driven feedback loop employing active learning algorithms (e.g., Bayesian optimization, artificial neural networks, and downhill simplex methods) to iteratively suggest new experimental parameters toward desired material properties.
Therefore, the excellent reproducibility for material syntheses when run on the SDL platform multiple times, the material agnostic behavior, the adaptability, and modularity, underscore the SDL’s reliability and potential as a transformative tool for advancing the development and applications of nano- and advanced materials, offering solutions for a sustainable future.
T2 - Gordon Research Seminar and Conference
CY - Ventura, CA, USA
DA - 24.01.2026
KW - Self-Driving Laboratories
KW - Materials Acceleration Platforms
KW - Nanomaterials
PY - 2026
AN - OPUS4-65596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eddah, Mustapha
T1 - Multi-Energy High Dynamic Range (HDR) Synchrotron X-ray Computed Tomography applied to LTCC samples
N2 - Synchrotron X-ray computed tomography (SXCT) is regularly used in materials science to correlate structural properties with macroscopic properties and to optimize manufacturing processes. The X-ray beam energy must be adapted to the sample properties, such as size and density. If both strongly and weakly absorbing materials are present, the contrast to the weakly absorbing materials is lost, resulting in image artifacts and a poor signal-to-noise ratio (SNR). One particular example is a low-temperature co-fired ceramics (LTCC), in which metal connections are embedded in a ceramic matrix and form 3-dimensional conducting structures. This article describes a method of combining SXCT scans acquired at different beam energies, significantly reducing metal artifacts, and improving image quality. We show how to solve the difficult task of merging the scans at low and high beam energy. Our proposed merging approach achieves up to 35 % improvement in SNR within ceramic regions adjacent to metallic conductors. In this way, previously inaccessible regions within the ceramic structure close to the metallic conductors are made accessible.
T2 - iCT 2026
CY - Linz, Austria
DA - 10.02.2026
KW - Synchrotron x-ray CT
KW - Reconstruction algorithm
KW - Low-Temperature cofired ceramics
KW - Data merging
PY - 2026
AN - OPUS4-65583
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eddah, Mustapha
T1 - Multi-Energy High Dynamic Range (HDR) Synchrotron X-ray Computed Tomography applied to LTCC samples
N2 - Synchrotron X-ray computed tomography (SXCT) is regularly used in materials science to correlate structural properties with macroscopic properties and to optimize manufacturing processes. The X-ray beam energy must be adapted to the sample properties, such as size and density. If both strongly and weakly absorbing materials are present, the contrast to the weakly absorbing materials is lost, resulting in image artifacts and a poor signal-to-noise ratio (SNR). One example is a low-temperature co-fired ceramics (LTCC), in which metal connections are embedded in a ceramic matrix and form 3-dimensional conducting structures. This article describes a method of combining SXCT scans acquired at different beam energies, significantly reducing metal artifacts, and improving image quality. We show how to solve the difficult task of merging the scans at low and high beam energy. Our proposed merging approach achieves up to 35% improvement in SNR within ceramic regions adjacent to metallic conductors. In this way, previously inaccessible regions within the ceramic structure close to the metallic conductors are made accessible.
T2 - iCT 2026
CY - Linz, Austria
DA - 10.02.2026
KW - Synchrotron x-ray CT
KW - Multi-energy CT
KW - Low-Temperature cofired ceramics
PY - 2026
AN - OPUS4-65586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - WójciaK, K.
A1 - Tokarski, T.
A1 - Cios, G.
A1 - Winkelmann, A.
A1 - Chulist, R.
A1 - Nolze, G.
T1 - Unconventional Applications of Electron Backscattering Diffraction (EBSD) in Metallic Materials
N2 - Electron backscattered diffraction is widely used for phase and orientation imaging of crystalline specimens. Despite the inherent complexity of diffraction images, current analysis methodologies typically focus on the position of Kikuchi bands or direct comparisons between experimental and simulated patterns. These approaches require prior knowledge of the phases to be analyzed, limiting their applicability in certain scenarios. This paper introduces an alternative methodology, crystallographic analysis of lattice metric, which extracts phase and orientation information directly from the registered diffraction pattern without requiring predefined standards. The paper outlines the methodology, discusses limitations, and demonstrates possible application in phase analysis, lattice parameter ratio mapping, and qualitative lattice distortion mapping.
KW - EBSD
KW - Virtual dark-field imaging
KW - Lattice distortion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656014
DO - https://doi.org/10.24425/amm.2025.156241
VL - 70
IS - 4
SP - 1619
EP - 1626
AN - OPUS4-65601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mangarova, Dilyana B.
A1 - Kaufmann, Jan Ole
A1 - Brangsch, Julia
A1 - Kader, Avan
A1 - Möckel, Jana
A1 - Heyl, Jennifer L.
A1 - Verlemann, Christine
A1 - Adams, Lisa C.
A1 - Ludwig, Antje
A1 - Reimann, Carolin
A1 - Poller, Wolfram C.
A1 - Niehaus, Peter
A1 - Karst, Uwe
A1 - Taupitz, Matthias
A1 - Hamm, Bernd
A1 - Weller, Michael G.
A1 - Makowski, Marcus R.
T1 - ADAMTS4-Specific MR Peptide Probe for the Assessment of Atherosclerotic Plaque Burden in a Mouse Model
N2 - Introduction
Atherosclerosis is the underlying cause of multiple cardiovascular pathologies. The present-day clinical imaging modalities do not offer sufficient information on plaque composition or rupture risk. A disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4) is a strongly upregulated proteoglycan-cleaving enzyme that is specific to cardiovascular diseases, inter alia, atherosclerosis.
Materials and Methods
Male apolipoprotein E-deficient mice received a high-fat diet for 2 (n = 11) or 4 months (n = 11). Additionally, a group (n = 11) receiving pravastatin by drinking water for 4 months alongside the high-fat diet was examined. The control group (n = 10) consisted of C57BL/6J mice on standard chow. Molecular magnetic resonance imaging was performed prior to and after administration of the gadolinium (Gd)-based ADAMTS4-specific probe, followed by ex vivo analyses of the aortic arch, brachiocephalic arteries, and carotid arteries. A P value <0.05 was considered to indicate a statistically significant difference.
Results
With advancing atherosclerosis, a significant increase in the contrast-to-noise ratio was measured after intravenous application of the probe (mean precontrast = 2.25; mean postcontrast = 11.47, P < 0.001 in the 4-month group). The pravastatin group presented decreased ADAMTS4 expression. A strong correlation between ADAMTS4 content measured via immunofluorescence staining and an increase in the contrast-to-noise ratio was detected (R2 = 0.69). Microdissection analysis revealed that ADAMTS4 gene expression in the plaque area was significantly greater than that in the arterial wall of a control mouse (P < 0.001). Laser ablation–inductively coupled plasma–mass spectrometry confirmed strong colocalization of areas positive for ADAMTS4 and Gd.
Conclusions
Magnetic resonance imaging using an ADAMTS4-specific agent is a promising method for characterizing atherosclerotic plaques and could improve plaque assessment in the diagnosis and treatment of atherosclerosis.
N2 - Einleitung
Atherosklerose ist die Ursache für zahlreiche Herz-Kreislauf-Erkrankungen. Die derzeitigen klinischen Bildgebungsverfahren liefern keine ausreichenden Informationen über die Zusammensetzung von Plaques oder das Risiko einer Ruptur. A Disintegrin and Metalloproteinase with Thrombospondin Motifs 4 (ADAMTS4) ist ein stark hochreguliertes Proteoglykan-spaltendes Enzym, das unter anderem bei Herz-Kreislauf-Erkrankungen wie Atherosklerose spezifisch auftritt.
Materialien und Methoden
Männliche Apolipoprotein-E-defiziente Mäuse erhielten 2 (n = 11) oder 4 Monate lang (n = 11) eine fettreiche Ernährung. Zusätzlich wurde eine Gruppe (n = 11) untersucht, die 4 Monate lang neben der fettreichen Ernährung Pravastatin über das Trinkwasser erhielt. Die Kontrollgruppe (n = 10) bestand aus C57BL/6J-Mäusen, die mit Standardfutter ernährt wurden. Vor und nach der Verabreichung der gadolinium (Gd)-basierten ADAMTS4-spezifischen Sonde wurde eine molekulare Magnetresonanztomographie durchgeführt, gefolgt von Ex-vivo-Analysen des Aortenbogens, der Arteria brachiocephalica und der Arteria carotis. Ein P-Wert < 0,05 wurde als statistisch signifikanter Unterschied gewertet.
Ergebnisse
Mit fortschreitender Atherosklerose wurde nach intravenöser Anwendung der Sonde ein signifikanter Anstieg des Kontrast-Rausch-Verhältnisses gemessen (Mittelwert vor Kontrastmittelgabe = 2,25; Mittelwert nach Kontrastmittelgabe = 11,47, P < 0,001 in der 4-Monats-Gruppe). Die Pravastatin-Gruppe zeigte eine verminderte ADAMTS4-Expression. Es wurde eine starke Korrelation zwischen dem mittels Immunfluoreszenzfärbung gemessenen ADAMTS4-Gehalt und einem Anstieg des Kontrast-Rausch-Verhältnisses festgestellt (R2 = 0,69). Die Mikrodissektionsanalyse ergab, dass die ADAMTS4-Genexpression im Plaque-Bereich signifikant höher war als in der Arterienwand einer Kontrollmaus (P < 0,001). Laserablation-induktiv gekoppelte Plasma-Massenspektrometrie bestätigte eine starke Kolokalisierung von ADAMTS4- und Gd-positiven Bereichen.
Schlussfolgerungen
Die Magnetresonanztomographie mit einem ADAMTS4-spezifischen Kontrastmittel ist eine vielversprechende Methode zur Charakterisierung atherosklerotischer Plaques und könnte die Plaquebewertung in der Diagnose und Behandlung von Atherosklerose verbessern.
KW - Peptide Aptamer
KW - MRI Probe
KW - Magnetic resonance imaging (MRI)
KW - Peptide libraries
KW - Laser ablation–inductively coupled plasma–mass spectrometry
KW - ICP MS
KW - Imaging
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635832
DO - https://doi.org/10.1097/RLI.0000000000001152
SN - 1536-0210
VL - 60
IS - 8
SP - 499
EP - 507
PB - Ovid Technologies (Wolters Kluwer Health)
CY - Philadelphia, Pennsylvania, USA
AN - OPUS4-63583
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bosc-Bierne, Gaby
A1 - Weller, Michael G.
T1 - Investigation of impurities in peptide pools
T1 - Untersuchung von Verunreinigungen in Peptidpools
N2 - Peptide pools are important research tools in different biomedical fields. They consist of a complex mixture of defined peptides, which places high demands on the production and quality control of these products. Previously it has been shown that the combination of UHPLC with high-resolution mass-spectrometry (HRMS) is a fast and powerful method to confirm the relative concentration and the structural identity of all peptides expected to be in the pool. In this work, the additional information contained in the UV chromatograms and mass spectra is used to search for impurities due to synthesis by-products and degradation during storage and transportation and to identify possible analytical artifacts. It was shown that most impurities are only present in trace amounts and can be considered uncritical for most applications. The most frequent and perhaps unexpected impurities were homo- and heterodimers caused by the free cysteines contained in these peptide pools. Furthermore, pyroglutamate and aspartimide formation, deamidation, methionine oxidation, and amino acid deletions could be found. This list is not intended to be comprehensive, but rather a brief guide to quickly identify impurities and, in the long term, to suggest possible changes in the composition of the peptide pools to avoid such impurities by design or by special precautions.
N2 - Peptidpools sind wichtige Forschungsinstrumente in verschiedenen biomedizinischen Bereichen. Sie bestehen aus einer komplexen Mischung definierter Peptide, was hohe Anforderungen an die Herstellung und Qualitätskontrolle dieser Produkte stellt. In der Vergangenheit wurde gezeigt, dass die Kombination von UHPLC mit hochauflösender Massenspektrometrie (HRMS) eine schnelle und leistungsfähige Methode zur Bestätigung der relativen Konzentration und der strukturellen Identität aller Peptide ist, die in dem Pool erwartet werden. In dieser Arbeit werden die zusätzlichen Informationen, die in den UV-Chromatogrammen und Massenspektren enthalten sind, genutzt, um nach Verunreinigungen zu suchen, die auf Nebenprodukte der Synthese und den Abbau während der Lagerung und des Transports zurückzuführen sind, und um mögliche analytische Artefakte zu identifizieren. Es hat sich gezeigt, dass die meisten Verunreinigungen nur in Spuren vorhanden sind und für die meisten Anwendungen als unkritisch angesehen werden können. Die häufigsten und vielleicht unerwartetsten Verunreinigungen waren Homo- und Heterodimere, die durch die in diesen Peptidpools enthaltenen freien Cysteine verursacht werden. Außerdem wurden Pyroglutamat- und Aspartimidbildung, Deamidierung, Methioninoxidation und Aminosäuredeletionen festgestellt. Diese Liste erhebt keinen Anspruch auf Vollständigkeit, sondern ist eher ein kurzer Leitfaden, um Verunreinigungen schnell zu identifizieren und langfristig mögliche Änderungen in der Zusammensetzung der Peptidpools vorzuschlagen, um solche Verunreinigungen durch Design oder besondere Vorsichtsmaßnahmen zu vermeiden.
KW - Synthetic peptides
KW - Degradation
KW - Synthetic artifacts
KW - Peptide losses
KW - Stability of peptides
KW - Disulfide dimers
KW - Cysteine dimers
KW - Isomers
KW - Cysteine alkylation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626987
DO - https://doi.org/10.3390/separations12020036
SN - 2297-8739
VL - 12
IS - 2
SP - 1
EP - 18
PB - MDPI AG
CY - Basel
AN - OPUS4-62698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Döring, Sarah
A1 - Wulfes, Birte S.
A1 - Atanasova, Aleksandra
A1 - Jaeger, Carsten
A1 - Walzel, Leopold
A1 - Tscheuschner, Georg
A1 - Flemig, Sabine
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Konthur, Zoltán
A1 - Weller, Michael G.
T1 - Corundum Particles as Trypsin Carrier for Efficient Protein Digestion
N2 - Reusable enzyme carriers are valuable for proteomic workflows, yet many supports are expensive or lack robustness. This study describes the covalent immobilization of recombinant trypsin on micrometer-sized corundum particles and assesses their performance in protein digestion and antibody analysis. The corundum surface was cleaned with potassium hydroxide, silanized with 3-aminopropyltriethoxysilane and activated with glutaraldehyde. Recombinant trypsin was then attached, and the resulting imines were reduced with sodium cyanoborohydride. Aromatic amino acid analysis (AAAA) estimated an enzyme loading of approximately 1 µg/mg. Non-specific adsorption of human plasma proteins was suppressed by blocking residual aldehydes with a Tris-glycine-lysine buffer. Compared with free trypsin, immobilization shifted the temperature optimum from 50 to 60 °C and greatly improved stability in 1 M guanidinium hydrochloride. Activity remained above 80 % across several reuse cycles, and storage at 4 °C preserved functionality for weeks. When applied to digesting the NISTmAb, immobilized trypsin provided peptide yields and sequence coverage comparable to soluble enzyme and outperformed it at elevated temperatures. MALDI-TOF MS analysis of Herceptin digests yielded fingerprint spectra that correctly identified the antibody and achieved >60 % sequence coverage. The combination of low cost, robustness and analytical performance makes corundum-immobilized trypsin an attractive option for research and routine proteomic workflows.
KW - Aluminum oxide
KW - Mass spectrometry
KW - Enzyme immobilization
KW - Antibodies
KW - Protein quantification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647944
DO - https://doi.org/10.20944/preprints202510.2002.v1
SP - 1
EP - 22
PB - Preprints.org
AN - OPUS4-64794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costa, Elena
A1 - Climent Terol, Estela
A1 - Ast, S.
A1 - Weller, Michael G.
A1 - Canning, J.
A1 - Rurack, Knut
T1 - Development of a lateral flow test for rapid pyrethroid detection using antibody-gated indicator-releasing hybrid materials
N2 - The employment of type-I pyrethroids for airplane disinfection in recent years underlines the necessity to develop sensing schemes for the rapid detection of these pesticides directly at the point-of-use. Antibody-gated indicator-releasing materials were thus developed and implemented with test strips for lateral-flow assay-based analysis employing a smartphone for readout. Besides a proper matching of pore sizes and gating macromolecules, the functionalization of both the material's outer surface as well as the strips with PEG chains enhanced system performance. This simple assay allowed for the detection of permethrin as a target molecule at concentrations down to the lower ppb level in less than 5 minutes.
KW - Lateral flow test
KW - Gated hybrid material
KW - Fluorescence
KW - Smartphone readout device
KW - Pyrethroid
KW - Pesticide
KW - Insecticide
KW - SBA-15
KW - Permethrin
PY - 2020
DO - https://doi.org/10.1039/d0an00319k
SN - 0003-2654
SN - 1364-5528
VL - 145
IS - 10
SP - 3490
EP - 3494
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-50756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bahri, Marwa
T1 - Ortsspezifische Biokonjugation von humanen Antikörpern mit IgG-bindenden Peptiden
N2 - Es wurde im Rahmen dieser Arbeit eine neue Methode der Biokonjugation entwickelt, die es ermöglicht humane Antikörper ortspezifisch mit IgG-bindenden Peptiden zu konjugieren. Als Basis fungierte ein Peptid, welches für den Einsatz gezielt modifiziert wurde. So sollte am C-Terminus ein Biotin eingefügt werden, dass für die spätere Detektion der Biokonjugation genutzt werden kann, während am N-Terminus ein Cross-Linker für die kovalente Bindung zum Antikörper eingefügt wurde. Das Biotin wurde mittels Biotin-Lysin eingebaut. Dies hat den Vorteil, dass die modifizierte Aminosäure direkt in der SPPS genutzt werden kann. Auch der Cross-Linker soll schon während der SPPS in das Peptid integriert werden. Als Cross Linker wurden die zwei heterobifunktionellen Succinimidyl(3-bromoacetamid)propionate und Succinimidyl(4-iodacetyl)aminobenzoat untersucht. Die Aktivierung des Peptides mit dem SBAP-Cross-Linker erfolgte am besten im pH-Bereich zwischen 7,0 und 9,0. Die Modifizierung des Peptides mit dem Iodid-Cross-Linker SIAB unter den gleichen Bedingungen zeigte allerdings keine zufriedenstellenden Ergebnisse. Da das erste Peptid allerdings in den Folgeexperimenten sehr gute Ergebnisse zeigte, musste kein weiterer Linker getestet werden. Zusätzlich zu der Cross-Linker-Wahl sollte der Abstand zwischen dem Cross-Linker und dem Grundgerüst des Peptides auf den Einfluss der Bindung untersucht werden. Dazu wurden drei Kontrollpeptide synthetisiert, die entweder um zwei Aminosäuren zwischen dem ursprünglichen N-Terminus des Peptides und dem SBAP-Linker verlängert wurden, keinen SBAP-Linker beinhalten oder die Verlängerung ohne SBAP-Linker besaßen. Die erfolgreiche Synthese aller vier Peptide wurde mittels MALDI-TOF-MS bestätigt.
KW - Peptide
KW - Bioconjugation
KW - Crosslinker
PY - 2020
SP - 1
EP - 82
PB - Humboldt-Universität zu Berlin
CY - Berlin
AN - OPUS4-54659
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Topical collection: Analytical methods and applications in the materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - 150th anniversary
KW - ABC
KW - Analysis
KW - Analytical sciences
KW - BAM
KW - Collection
KW - Environment
KW - Fluorescence
KW - Life sciences
KW - Limit of detection
KW - Material sciences
KW - Method
KW - Nanoparticle
KW - Pollutant
KW - Quality assurance
KW - Reference material
KW - Sensor
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://link.springer.com/journal/216/topicalCollection/AC_16a2ef9b81853377e321ef84d9c4a431
SN - 1618-2642
SN - 1618-2650
VL - 414
SP - 4267
EP - 4529
PB - Springer
CY - Berlin
AN - OPUS4-55670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Boldyreva, E.
A1 - Belenguer, A. M.
A1 - Emmerling, Franziska
A1 - Boldyrev, V. V.
T1 - Tribochemistry, mechanical alloying, mechanochemistry: what is in a name?
N2 - Over the decades, the application of mechanical force to influence chemical reactions has been called by various names: mechanochemistry, tribochemistry, mechanical alloying, to name but a few. The evolution of these terms has largely mirrored the understanding of the field. But what is meant by these terms, why have they evolved, and does it really matter how a process is called? Which parameters should be defined to describe unambiguously the experimental conditions such that others can reproduce the results, or to allow a meaningful comparison between processes explored under different conditions? Can the information on the process be encoded in a clear, concise, and self-explanatory way? We address these questions in this Opinion contribution, which we hope will spark timely and constructive discussion across the international mechanochemistry community.
KW - Mechanochemistry
KW - Tribochemistry
KW - Mechanical alloying
KW - Tribology
KW - Mechanical activation
KW - Nomenclature
KW - Mechanochemical pictographs
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523291
DO - https://doi.org/10.3389/fchem.2021.685789
SN - 2296-2646
VL - 9
SP - 1
EP - 29
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-52329
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira, P. F. M.
A1 - Torresi, R.
A1 - Emmerling, Franziska
A1 - Carmago, P.
T1 - Challenges and opportunities in the bottom-up mechanochemical synthesis of noble metal nanoparticles
N2 - Mechanochemistry is a promising alternative to solution-based protocols across the chemical sciences, enabling different types of chemistries in solvent-free and environmentally benign conditions. The use of mechanical energy to promote physical and chemical transformations has reached a high level of refinement, allowing for the design of sophisticated molecules and nanostructured materials. Among them, the synthesis of noble metal nanoparticles deserves special attention due to their catalytic applications. In this review, we discuss the recent progress on the development of mechanochemical strategies for the controlled synthesis of noble metal nanostructures. We start by covering the fundamentals of different preparation routes, namely top-down and bottom-up approaches. Next, we focus on the key examples of the mechanochemical synthesis of non-supported and supported metal nanoparticles as well as hybrid nanomaterials containing noble metals. In these examples, in addition to the principles and synthesis mechanisms, their performances in catalysis are discussed. Finally, a perspective of the field is given, where we discuss the opportunities for future work and the challenges of mechanochemical synthesis to produce well-defined noble metal nanoparticles.
KW - Mechanochemistry
KW - Nanoparticles
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512080
DO - https://doi.org/10.1039/D0TA05183G
VL - 8
IS - 32
SP - 16114
AN - OPUS4-51208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Schröder, V.
A1 - List-Kratochvil, E.
A1 - Emmerling, Franziska
T1 - Mechanochemical Syntheses of Isostructural Luminescent Cocrystals of 9-Anthracenecarboxylic Acid with two Dipyridines Coformers
N2 - Tuning and controlling the solid-state photophysical properties of organic luminophore are very important to develop next-generation organic luminescent materials. With the aim of discovering new functional luminescent materials, new cocrystals of 9-anthracene carboxylic acid (ACA) were prepared with two different dipyridine coformers: 1,2-bis(4-pyridyl)ethylene and 1,2-bis(4-pyridyl)ethane. The cocrystals were successfully obtained by both mechanochemical approaches and conventional solvent crystallization. The newly obtained crystalline solids were characterized thoroughly using a combination of single crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and thermogravimetric analysis. Structural analysis revealed that the cocrystals are isostructural, exhibiting two-fold interpenetrated hydrogen bonded networks. While the O–H···N hydrogen bonds adopts a primary role in the stabilization of the cocrystal phases, the C–H···O hydrogen bonding interactions appear to play a significant role in guiding the three-dimensional assembly. Both π···π and C–H···π interactions assist in stabilizing the interpenetrated structure. The photoluminescence properties of both the starting materials and cocrystals were examined in their solid states. All the cocrystals display tunable photophysical properties as compared to pure ACA. Density functional theory simulations suggest that the modified optical properties result from charge transfers between the ACA and coformer molecules in each case. This study demonstrates the potential of crystal engineering to design solid-state luminescence switching materials through cocrystallization.
KW - Cocrystal
KW - Mechanochemical synthesis
KW - Luminescence
KW - X-ray diffraction
KW - DFT calculation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518226
DO - https://doi.org/10.3390/cryst10100889
VL - 10
IS - 10
SP - 889
PB - MDPI
AN - OPUS4-51822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kervarec, M.-C.
A1 - Kemnitz, E.
A1 - Scholz, G.
A1 - Rudic, S.
A1 - Jäger, Christian
A1 - Braun, T.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - A HF Loaded Lewis-Acidic Aluminium Chlorofluoride for Hydrofluorination Reactions
N2 - The very strong Lewis acid aluminium chlorofluo-ride (ACF) was loaded with anhydrous HF. The interactionbetween the surface of the catalyst and HF was investigatedusing a variety of characterization methods, which revealed he formation of polyfluorides. Moreover, the reactivity ofthe HF-loaded ACF towards the hydrofluorination of alkyneswas studied.
KW - Aluminium
KW - HF
KW - Hydrofluorination
KW - Metal fluorides
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508360
DO - https://doi.org/10.1002/chem.202001627
VL - 26
SP - 1
PB - Wiley Online Libary
AN - OPUS4-50836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, A.
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L. J.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol Dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment.
The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled Plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151Eu-Mössbauer spectroscopy, X-ray total scattering, and Extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve Separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - Lanthanides
KW - Structural Analysis
KW - Separation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510821
DO - https://doi.org/10.1002/chem.202002653
SN - 0947-6539
VL - 26
SP - 1
EP - 8
PB - WILEY-VCH Verlag GmbH & co. KGaA
AN - OPUS4-51082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, Annika
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - PQQ
KW - Lanthanoide
KW - Coordination chemistry
KW - Rare earth elements separations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512707
DO - https://doi.org/10.1002/chem.202002653
VL - 26
IS - 44
SP - 10133
EP - 10139
AN - OPUS4-51270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tantardini, C.
A1 - Michalchuk, Adam
A1 - Samtsevich, A.
A1 - Rota, C.
A1 - Kvashnin, A. G.
T1 - The Volumetric Source Function: Looking Inside van der Waals Interactions
N2 - The study of van der Waals interactions plays a central role in the understanding of bonding across a range of biological, chemical and physical phenomena. The presence of van der Waals interactions can be identified through analysis of the reduced density gradient, a fundamental parameter at the core of Density Functional Theory. An extension of Bader’s Quantum Theory of Atoms in Molecules is developed here through combination with the analysis of the reduced density gradient. Through this development, a new quantum chemical topological tool is presented: the volumetric source function.
This technique allows insight into the atomic composition of van der Waals interactions, offering the first route towards applying the highly successful source function to these disperse interactions. A new algorithm has been implemented in the open-source code, CRITIC2, and tested on acetone, adipic and maleic acids molecular crystals, each stabilized by van der Waals interactions. This novel technique for studying van der Waals interactions at an atomic level offers unprecedented opportunities in the fundamental study of intermolecular interactions and molecular design for crystal engineering, drug design and bio-macromolecular processes.
KW - Noncovalent interactions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507911
DO - https://doi.org/10.1038/s41598-020-64261-4
VL - 10
IS - 1
SP - 7816
AN - OPUS4-50791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quiroz, J.
A1 - de Oliveira, P. F. M.
A1 - Shetty, S.
A1 - Oropeza, F.
A1 - Peña O’Shea, V.
A1 - Rodrigues, L.
A1 - Rodrigues, M.
A1 - Torresi, R.
A1 - Emmerling, Franziska
A1 - Camargo, P.
T1 - Bringing earth-abundant plasmonic catalysis to light: Gram-scale mechanochemical synthesis and tuning of activity by dual excitation of antenna and reactor sites
N2 - The localized surface plasmon resonance (LSPR) excitation in plasmonic nanoparticles (NPs) in the visible and near-infrared ranges is currently at the forefront of improving photocatalytic performances via plasmonic photocatalysis. One bottleneck of this field is that the NPs that often display the best optical properties in the visible and near-infrared ranges are based on expensive noble metals such as silver (Ag) and gold (Au). While earth-abundant plasmonic materials have been proposed together with catalytic metals in antenna–reactor systems, their performances remain limited by their optical properties. Importantly, the synthesis of plasmonic photocatalysts remains challenging in terms of scalability while often requiring several steps, high temperatures, and special conditions. Herein, we address these challenges by developing a one-pot, gram-scale, room-temperature synthesis of earth-abundant plasmonic photocatalysts while improving their activities beyond what has been dictated by the LSPR excitation of the plasmonic component. We describe the mechanochemical synthesis of earth-abundant plasmonic photocatalysts by using MoO3 (antenna) and Au (reactor) NPs as a proof-of-concept example and demonstrate that the dual plasmonic excitation of antenna and reactor sites enables the tuning of plasmonic photocatalytic performances toward the reductive coupling of nitrobenzene to azobenzene as a model reaction. In addition to providing a pathway to the facile and gram-scale synthesis of plasmonic photocatalysts, the results reported herein may open pathways to improved activities in plasmonic catalysis.
KW - MoO3
KW - Au nanoparticles
KW - Localized surface plasmon resonance
KW - Plasmonic photocatalysis
KW - Nitrobenzene reduction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532089
DO - https://doi.org/10.1021/acssuschemeng.1c02063
VL - 9
IS - 29
SP - 9750
EP - 9760
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-53208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bornemann-Pfeiffer, Martin
A1 - Wolf, Jakob
A1 - Meyer, Klas
A1 - Kern, S.
A1 - Angelone, D.
A1 - Leonov, A.
A1 - Cronin, L.
A1 - Emmerling, Franziska
T1 - Standardization and control of Grignard reactions in a universal chemical synthesis machine using online NMR
T1 - Standardisierung und Kontrolle von Grignard-Reaktionen mittels Online-NMR in einer universellen chemischen Syntheseplattform
N2 - A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. “Chemputer” which is capable of small-molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online-NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements.
N2 - Ein Problem der chemischen Literatur ist die fehlende Standardisierung bezüglich genauer Bedingungen, auch Echtzeit-Korrekturen sind ohne Expertenwissen nur schwer möglich. Dieser Mangel an Details erschwert experimentelle Reproduzierbarkeit, da Schritte oft mehrdeutig sind und daher von implizitem Wissen abhängen. Hier präsentieren wir die Integration von Online-NMR Spektroskopie in eine automatisierte chemische Syntheseplattform (CSM aka. “Chemputer”, unter Verwendung einer universellen Programmiersprache zur Synthese kleiner Moleküle fähig), um eine automatisierte Analyse und Anpassung von Reaktionen im laufenden Betrieb zu ermöglichen. Das System wurde anhand von Grignard-Reaktionen, die aufgrund ihrer Bedeutung für die Synthese ausgewählt wurden, validiert und einem Härtetest unterzogen. Synthesen wurden in Echtzeit mit Online-NMR überwacht, und die Spektren wurden während der Reaktionen kontinuierlich aufgenommen und analysiert. Dies zeigt, dass der Chemputer dynamisch mittels einer Regelung kontrolliert werden kann, um die Reaktionsbedingungen entsprechend den Anforderungen des Benutzers zu optimieren.
KW - Grignard reaction
KW - NMR spectroscopy
KW - Process analytical technology
KW - Process control
KW - Grignard-Reaktion
KW - NMR-Spektroskopie
KW - Prozessanalytik
KW - Prozesskontrolle
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531260
DO - https://doi.org/10.1002/anie.202106323
SN - 1521-3773
SN - 1433-7851
N1 - Bibliografische Angaben für die deutsche Version: Angewandte Chemie 2021, Jg. 133, S. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323 - Bibliographic information for the German version: Angewandte Chemie 2021, vol. 133, p. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323
VL - 60
IS - 43
SP - 1
EP - 6
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53126
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Christopher, I
A1 - Michalchuk, Adam
A1 - Pulham, C.
A1 - Morrison, C.
T1 - Towards Computational Screening for New Energetic Molecules: Calculation of Heat of Formation and Determination of Bond Strengths by Local Mode Analysis
N2 - The reliable determination of gas-phase and solid-state heats of formation are important considerations in energetic materials research. Herein, the ability of PM7 to calculate the gas-phase heats of formation for CNHO-only and inorganic compounds has been critically evaluated, and for the former, comparisons drawn with isodesmic equations and Atom equivalence methods. Routes to obtain solid-state heats of formation for a range of singlecomponent molecular solids, salts, and co-crystals were also evaluated. Finally, local vibrational mode analysis has been used to calculate bond length/force constant curves for seven different chemical bonds occurring in CHNO-containing molecules, which allow for rapid identification of the weakest bond, opening up great potential to rationalise decomposition pathways. Both metrics are important tools in rationalising the design of new energetic materials through computational screening processes.
KW - Energetic materials
KW - Density functional theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530371
DO - https://doi.org/10.3389/fchem.2021.726357
VL - 9
SP - 726357
AN - OPUS4-53037
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Rhim, S.-Y.
A1 - Schöder, V.
A1 - List-Kratochvil, E.
A1 - Emmerling, Franziska
T1 - Tuning the mechanical flexibility of organic molecular crystals by polymorphism for flexible optical waveguides
N2 - The ability to selectively tune the optical and the mechanical properties of organic molecular crystals offers a promising approach towards developing flexible optical devices. These functional properties are sensitive to crystallographic packing features and are hence expected to vary with polymorphic modification. Using as a model system the photoluminescent material 4-bromo-6-[(6-chloropyridin-2-ylimino)methyl]phenol (CPMBP), we herein demonstrate the simultaneous tuning of mechanical flexibility and photoluminescence properties via polymorphism. Two new polymorphic forms of CPMBP were obtained from a solution and fully characterised using a combination of experiments and density functional theory simulations. These polymorphic forms exhibit remarkably distinct mechanical properties and an order of magnitude difference in photoluminescence quantum yield. The mechanically plastic form has a higher quantum yield than the brittle polymorphic form. However, their photoluminescence emission profile is largely unaffected by the observed polymorphism, thereby demonstrating that the optical properties and bulk mechanical properties can in principle be tuned independently. By distinguishing between active (involving absorption and emission) and passive (involving no absorption) light propagation, the waveguiding properties of the plastic form of CPMBP (form II) were explored using the straight and bent crystals to highlight the potential applications of CPMBP in designing flexible optical devices. Our results demonstrated that polymorph engineering would be a promising avenue to achieve concurrent modulation of the optical and mechanical properties of photoluminescent molecular crystals for next-generation flexible optical device applications.
KW - Mechanochemistry
KW - Flexible
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532075
DO - https://doi.org/10.1039/d1ce00642h
VL - 23
IS - 34
SP - 5815
EP - 5825
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-53207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, G.
A1 - Xu, W.
A1 - Kemnitz, E.
A1 - Emmerling, Franziska
T1 - Structure and properties of fluorinated and non-fluorinated Ba-coordination polymers - the position of fluorine makes the difference
N2 - As the most electronegative element, fluorine has a strong influence on material properties such as absorption behaviour or chemical and thermal stability. Fluorine can be easily integrated into coordination polymers (CPs) via a fluorinated acetate, here trifluoroacetate in Ba(CF3COO)2, or directly via a metal fluorine bond (BaF(CH3COO)). In the present study both possibilities of fluorine integration were tested and their effect on structure and properties of barium coordination polymers was investigated in comparison with the non-fluorinated barium acetate (Ba(CH3COO)2). In addition to the study of their thermal behaviour and their decomposition temperature, the CPs structures were tested for their application as possible anode materials in lithium ion batteries and for their sorption of water and ammonia. The properties of the CPs can be traced back to the individual structural motifs and could thus trigger new design ideas for CPs in LIBs and/or catalysis.
KW - Alkaline earth metal coordination polymers
KW - Lithium-ion battery
KW - Water stability
KW - Fluorine coordination
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524041
DO - https://doi.org/10.1002/zaac.202000360
SN - 0044-2313
VL - 647
IS - 9
SP - 1014
EP - 1024
PB - Wiley-VCH GmbH
AN - OPUS4-52404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Kulla, Hannes
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
T1 - Advances in Nickel Nanoparticle Synthesis via Oleylamine Route
N2 - Nickel nanoparticles are an active research area due to their multiple applications as catalysts in different processes. A variety of preparation techniques have been reported for the synthesis of these nanoparticles, including solvothermal, microwave-assisted, and emulsion techniques. The well-studied solvothermal oleylamine synthesis route comes with the drawback of needing standard air-free techniques and often space-consuming glassware. Here, we present a facile and straightforward synthesis method for size-controlled highly monodisperse nickel nanoparticles avoiding the use of, e.g., Schlenk techniques and space-consuming labware. The nanoparticles produced by this novel synthetic route were investigated using small-angle X-ray scattering, transmission electron microscopy, X-ray diffraction, and X-ray spectroscopy. The nanoparticles were in a size range of 4–16 nm, show high sphericity, no oxidation, and no agglomeration after synthesis.
KW - Nanoparticle synthesis
KW - Nickel nanoparticles
KW - SAXS
KW - TEM
KW - XAS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507531
DO - https://doi.org/10.3390/nano10040713
VL - 10
IS - 4
SP - 713
PB - MDPI
AN - OPUS4-50753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chewle, Surahit
A1 - Emmerling, Franziska
A1 - Weber, M.
T1 - Effect of choice of solvent on crystallization pathway of paracetamol: An experimental and theoretical case study
N2 - The choice of solvents influences crystalline solid formed during the crystallization of active pharmaceutical ingredients (API). The underlying effects are not always well understood because of the complexity of the systems. Theoretical models are often insufficient to describe this phenomenon. In this study, the crystallization behavior of the model drug paracetamol in different solvents was studied based on experimental and molecular dynamics data. The crystallization process was followed in situ using time-resolved Raman spectroscopy. Molecular dynamics with simulated annealing algorithm was used for an atomistic understanding of the underlying processes. The experimental and theoretical data indicate that paracetamol molecules adopt a particular geometry in a given solvent predefining the crystallization of certain polymorphs
KW - Crystallization
KW - Nucleation
KW - Polymorphism
KW - Raman spectroscopy
KW - Cassical nucleation theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520052
DO - https://doi.org/10.3390/cryst10121107
SN - 2073-4352
VL - 10
IS - 12
SP - 1
EP - 10
PB - MDPI
CY - Basel
AN - OPUS4-52005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, X.
A1 - Michalchuk, Adam
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Pulham, C.
T1 - High-pressure reversibility in a plastically flexible coordination polymer crystal
N2 - Single crystals which exhibit mechanical flexibility are promising materials for advanced technological applications. Before such materials can be used, a detailed understanding of the mechanisms of bending is needed. Using single crystal X-ray diffraction and microfocus Raman spectroscopy, we study in atomic detail the high-pressure response of the plastically flexible coordination polymer [Zn(μ-Cl)2(3,5-dichloropyridine)2]n (1). Contradictory to three-point bending, quasi-hydrostatic compression of (1) is completely reversible, even following compression to over 9 GPa. A structural phase transition is observed at ca. 5 GPa. DFT calculations show this transition to result from the pressure-induced softening of low-frequency vibrations. This phase transition is not observed during three-point-bending. Microfocus synchrotron X-ray diffraction revealed that bending yields significant mosaicity, as opposed to compression. Hence, our studies indicate of overall disparate mechanical responses of bulk flexibility and quasi-hydrostatic compression within the same crystal lattice. We suspect this to be a general feature of plastically bendable materials.
KW - High pressure
KW - Density functional theory
KW - Mechanically flexible crystals
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530360
DO - https://doi.org/10.1038/s41467-021-24165-x
VL - 12
IS - 1
SP - 3871
AN - OPUS4-53036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Gernhard, M.
A1 - Radnik, Jörg
A1 - Witt, Julia
A1 - Roth, C.
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis of fluorine-containing Co-doped zeolitic imidazolate frameworks for producing electrocatalysts
N2 - Catalysts derived from pyrolysis of metal organic frameworks (MOFs) are promising candidates to replace expensive and scarce platinum-based electrocatalysts commonly used in polymer electrolyte membrane fuel cells. MOFs contain ordered connections between metal centers and organic ligands. They can be pyrolyzed into metal- and nitrogen-doped carbons, which show electrocatalytic activity toward the oxygen reduction reaction (ORR). Furthermore, metal-free heteroatom-doped carbons, such as N-F-Cs, are known for being active as well. Thus, a carbon material with Co-N-F doping could possibly be even more promising as ORR electrocatalyst. Herein, we report the mechanochemical synthesis of two polymorphs of a zeolitic imidazole framework, Co-doped zinc 2-trifluoromethyl-1H-imidazolate (Zn0.9Co0.1(CF3-Im)2). Time-resolved in situ X-ray diffraction studies of the mechanochemical formation revealed a direct conversion of starting materials to the products. Both polymorphs of Zn0.9Co0.1(CF3-Im)2 were pyrolyzed, yielding Co-N-F containing carbons, which are active toward electrochemical ORR.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Nobel-metal free electrocatalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546833
DO - https://doi.org/10.3389/fchem.2022.840758
SN - 2296-2646
VL - 10
IS - 840758
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, J.
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
T1 - Towards automation of the polyol process for the synthesis of silver nanoparticles
N2 - Metal nanoparticles have a substantial impact across diferent felds of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize silver nanoparticles often do not result in well-defned products, the main obstacles being high polydispersity or a lack of particle size tunability. We describe an automated approach to on-demand synthesis of adjustable particles with mean radii of 3 and 5 nm using the polyol route. The polyol process is a promising route for silver nanoparticles e.g., to be used as reference materials. We characterised the as-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties.
KW - Sillver
KW - Nanoparticles
KW - Automated synthesis
KW - Chemputer
KW - Scattering
KW - SAXS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546803
DO - https://doi.org/10.1038/s41598-022-09774-w
VL - 12
IS - 1
SP - 1
EP - 9
PB - Nature Springer
AN - OPUS4-54680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, G.
A1 - Marquardt, Julien
A1 - Emmerling, Franziska
T1 - Structural changes in Ba-compounds of different hardness induced by high-energy ball milling – evidenced by 137Ba NMR and X-ray powder diffraction
N2 - Changes in the global bulk and local structures, of three different barium compounds (BaZrO3, BaF2, and BaFCl),were induced by mechanical milling and followed using X-ray powder diffraction (PXRD), subsequent microstructure analysis, and 137Ba solid state NMR spectroscopy. Harder materials like BaZrO3 experience significantly higher structural changes upon milling than softer materials like BaF2. Moreover, soft materials with layered structures, like BaFCl, show a pronounced structural change during the milling process. By combining PXRD and solid state NMR, detailed information on the changes to the global and local structures were obtained, which are of interest for mechanochemical synthesis, mechanically treated catalysts or ionic conductors.
KW - Mechanochemistry
KW - X-ray diffraction
KW - Solid state NMR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547397
DO - https://doi.org/10.1002/zaac.202200026
SN - 0044-2313
VL - 648
IS - 10
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belenguer, A.
A1 - Lampronti, G.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
A1 - Sanders, J.
T1 - Quantitative reversible one pot interconversion of three crystalline polymorphs by ball mill grinding
N2 - We demonstrate here using a disulfide system the first example of reversible, selective, and quantitative transformation between three crystalline polymorphs by ball mill grinding. This includes the discovery of a previously unknown polymorph. Each polymorph is reproducibly obtained under well-defined neat or liquid-assisted grinding conditions, revealing subtle control over the apparent thermodynamic stability. We discovered that the presence of a contaminant as low as 1.5% mol mol−1 acting as a template is required to enable all these three polymorph transformations. The relative stabilities of the polymorphs are determined by the sizes of the nanocrystals produced under different conditions and by surface interactions with small amounts of added solvent. For the first time, we show evidence that each of the three polymorphs is obtained with a unique and reproducible crystalline size. This mechanochemical approach gives access to bulk quantities of metastable polymorphs that are inaccessible through recrystallisation.
KW - Mechanochemistry
KW - Polymorph
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549934
DO - https://doi.org/10.1039/D2CE00393G
SP - 1
EP - 7
PB - Royal Society of Chemistry
AN - OPUS4-54993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Heinekamp, Christian
A1 - Smales, Glen Jacob
A1 - Hodoroaba, Vasile-Dan
A1 - ten Elshof, J. E.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz
T1 - Template-free synthesis of mesoporous, amorphous transition metal phosphate materials
N2 - We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves a transformation of a precursor metal phosphate phase, called M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, NixCo1-x2+). It relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneously mesoporous phase, which forms while degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the metal coordination environment were followed with in-situ and ex-situ scattering and diffraction, as well as X -ray spectroscopy. Despite sharing the same precursor struvite structure, different amorphous and mesoporous structures were obtained depending on the involved transition metal. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions depending on a metal cation present in the analogous M-struvites. The amorphous structures of thermally decomposed Mg-, Ni- and NixCo1-x-struvites exhibit high surface areas and pore volumes (240 m²g-1 and 0.32 cm-3 g-1 for Mg and 90 m²g-1 and 0.13 cm-3 g-1 for Ni). We propose that the low-cost, environmentally friendly M-struvites could be obtained as recycling products from industrial and agricultural wastewaters. These waste products could be then upcycled into mesoporous TMPs through a simple thermal treatment for further applications, for instance, in (electro)catalysis.
KW - Struvite
KW - Pphosphates
KW - Transition metal
KW - In-situ SAXS/WAXS
KW - Mesoporosity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569503
DO - https://doi.org/10.1039/D2NR05630E
SN - 2040-3364
SP - 1
EP - 15
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-56950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Bhattacharya, Biswajit
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Fink, Friedrich
A1 - Feldmann, Ines
A1 - ten Elshof, J. E.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz
T1 - Thermally processed Ni-and Co-struvites as functional materials for proton conductivity
N2 - We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves the transformation of a precursor metal phosphate phase, called M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, NixCo1−x2+). It relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneously mesoporous phase, which forms during degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the metal coordination environment were followed by in situ and ex situ scattering and diffraction, as well as X-ray spectroscopy. Despite sharing the same precursor struvite structure, different amorphous and mesoporous structures were obtained depending on the involved transition metal. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions depending on the metal cation present in the analogous M-struvites. The amorphous structures of thermally decomposed Mg-, Ni- and NixCo1−x-struvites exhibit high surface areas and pore volumes (240 m2 g−1 and 0.32 cm−3 g−1 for Mg and 90 m2 g−1 and 0.13 cm−3 g−1 for Ni). We propose that the low-cost, environmentally friendly M-struvites could be obtained as recycling products from industrial and agricultural wastewaters. These waste products could be then upcycled into mesoporous TMPs through a simple thermal treatment for further application, for instance in (electro)catalysis.
KW - Struvite
KW - Phosphates
KW - Transition metals
KW - Proton conductivity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575862
DO - https://doi.org/10.1039/D3DT00839H
SN - 1477-9226
SP - 1
EP - 13
PB - Royal Society of Chemisty (RSC)
CY - London/Cambridge
AN - OPUS4-57586
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Ryll, T. W.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz Maciej
T1 - Phase stability studies on transition metal phosphates aided by an automated synthesis
N2 - Transition metal phosphates (TMPs) have attracted interest as materials for (electro-) catalysis, and electrochemistry due to their low-cost, stability, and tunability. In this work, an automated synthesis platform was used for the preparation of transition metal phosphate crystals to efficiently explore the multidimensional parameter space, determining the phase selection, crystal sizes, shapes. By using X-ray diffraction and spectroscopy-based methods and electron microscopy imaging, a complete characterization of the phase stability fields, phase transitions, and crystal morphology/sizes was achieved. In an automated three-reactant synthesis, the individual effect of each reactant species NH4+, M2+, and PO43- on the formation of transition metal phosphate phases: M-struvite NH4MPO4·6H2O, M-phosphate octahydrate M3(PO4)2·8H2O with M = Ni, Co and an amorphous phase, was investigated. The NH4+ concentration dictates the phase composition, morphology, and particle size in the Ni-system (crystalline Ni-struvite versus amorphous Ni-PO4 phase), whereas in the Co-system all reactant species - NH4+, Co2+, and PO43- - influence the reaction outcome equivalently (Co-struvite vs. Co-phosphate octahydrate). The coordination environment for all crystalline compounds and of the amorphous Ni-PO4 phase was resolved by X-ray absorption spectroscopy, revealing matching characteristics to its crystalline analogue, Ni3(PO4)2·8H2O. The automated synthesis turned out to be significantly advantageous for the exploration of phase diagrams due to its simple modularity, facile traceability, and enhanced reproducibility compared to a typical manual synthesis.
KW - Automated synthesis
KW - Phase diagrams
KW - Transition metals
KW - Phosphates
KW - Local structure
KW - Struvite
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579151
DO - https://doi.org/10.1039/D3CE00386H
VL - 25
IS - 30
SP - 4333
EP - 4344
PB - CrystEngComm
CY - London
AN - OPUS4-57915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Akhmetova, Irina
A1 - Das, Chayanika
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Synthesis and In Situ Monitoring of Mechanochemical Preparation of Highly Proton Conductive Hydrogen-Bonded Metal Phosphonates
N2 - Crystalline porous materials are recognized as promising proton conductors for the proton exchange membrane (PEM) in fuel cell technology owing to their tunable framework structure. However, it is still a challenging bulk synthesis for real-world applications of these materials. Herein, we report the mechanochemical gram-scale synthesis of two isostructural metal hydrogen-bonded organic frameworks (MHOFs) of Co(II) and Ni(II) based on 1-hydroxyethylidenediphosphonic acid (HEDPH4) with 2,2′-bipyridine (2,2′-bipy): Co(HEDPH3)2(2,2′-bipy)·H2O (1) and Ni(HEDPH3)2(2,2′-bipy)·H2O (2). In situ monitoring of the mechanochemical synthesis using different synchrotron-based techniques revealed a one-step mechanism – the starting materials are directly converted to the product. With the existence of extensive hydrogen bonds with amphiprotic uncoordinated phosphonate hydroxyl and oxygen atoms, both frameworks exhibited proton conduction in the range of 10–4 S cm–1 at room temperature under humid conditions. This study demonstrates the potential of green mechanosynthesis for bulk material preparation of framework-based solid-state proton conductors.
KW - Mechanochemistry
KW - Proton conductivity
KW - Metal Organic Frameworks
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577777
DO - https://doi.org/10.1021/acssuschemeng.2c07509
VL - 8
IS - 19
SP - 16687
EP - 16693
PB - ACS Publications
AN - OPUS4-57777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bui, M.
A1 - Hoffmann, K. F.
A1 - Braun, T.
A1 - Riedel, S.
A1 - Heinekamp, Christian
A1 - Scheurell, K.
A1 - Scholz, G.
A1 - Stawski, Tomasz
A1 - Emmerling, Franziska
T1 - An Amorphous Teflate Doped Aluminium Chlorofluoride:
A Solid Lewis-Superacid for the Dehydrofluorination of
Fluoroalkanes
N2 - Ananion-dopedaluminiumchlorofluoride AlCl0.1F2.8(OTeF5)0.1(ACF-teflate) was synthesized.The material contains pentafluor-oorthotellurate(teflate)groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by73 cm-1, which is larger than the shift for SbF5. Remarkably,ACF-teflate catalyzes dehydrofluorination reactions of mono-fluoroalkanes to yield olefins in C6D6. In these cases,no Friedel-Crafts products were formed.
KW - Aluminium fluorides
KW - Aluminium teflates
KW - C-F bond activation
KW - Lewis superacids
KW - Silanes
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572290
DO - https://doi.org/10.1002/cctc.202300350
SN - 1867-3880
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-57229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Goedecke, Caroline
A1 - Bannick, C.-G.
A1 - Abusafia, A.
A1 - Scheid, C.
A1 - Steinmetz, H.
A1 - Paul, Andrea
A1 - Beleites, C.
A1 - Braun, U.
T1 - Identification of microplastic pathways within a typical European urban wastewater system
N2 - In recent years, thermoextraction/desorption-gas chromatography/mass spectrometry (TED-GC/MS) has been developed as a rapid detection method for the determination of microplastics (MP) mass contents in numerous environmentally relevant matrices and, in particular, for the measurement of polymers in water samples without time-consuming sample preparation. The TED-GC/MS method was applied to investigate a typical European municipal wastewater system for possible MP masses. Such investigations are important in view of the recent revision of the Urban Wastewater Treatment Directive. Four different representative sampling sites were selected: greywater (domestic wastewater without toilet), combined sewer, and influent and effluent of a wastewater treatment plant (WWTP). All samples were collected by fractional filtration. Filtration was carried out over mesh sizes of 500, 100, 50, and in some cases, 5 µm. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) were detected in all samples, with the PE fraction dominating in all cases. Styrene-butadiene rubber which serves as an indication of tire abrasion, was only found in the influent of the WWTP. The highest MP mass contents were found in the combined sewer, so MP can become a source of pollution during heavy rain events when the capacity limits of the effluent are reached, and the polluted effluent is released uncontrolled into the environment. Based on the studies, MP retention from the WWTP could be estimated to be approximately 96%. Few trends in polymer type or mass contents were detected within the different fractions of the samples or when comparing samples to each other.
KW - Microplastics
KW - Microplastic analysis
KW - TED-GC/MS
KW - Microplastic pathways
KW - Mass contents
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568289
DO - https://doi.org/doi.org/10.1002/appl.202200078
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ahrens, M.
A1 - Braun, T.
A1 - Emmerling, Franziska
T1 - An amorphous Lewis-acidic zirconium chlorofluoride as HF shuttle: C–F bond activation and formation
N2 - An exceptional HF transfer reaction by C–F bond activation of fluoropentane and a subsequent hydrofluorination of alkynes at room temperature is reported. An amorphous Lewis-acidic Zr chlorofluoride serves as heterogeneous catalyst, which is characterised by an eightfold coordination environment at Zr including chlorine atoms. The studies are seminal in establishing sustainable fluorine chemistry.
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - HF-shuttle
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582249
DO - https://doi.org/10.1039/D3CC03164K
SN - 1359-7345
VL - 59
IS - 75
SP - 11224
EP - 11227
PB - RSC
CY - Cambridge
AN - OPUS4-58224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, Gudrun
A1 - Krahl, Thoralf
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Kemnitz, E.
T1 - Luminescent properties of Eu3+/Tb3+ doped fluorine containing coordination polymers
N2 - Lanthanides doped coordination polymers (CPs) with different binding motifs were synthesized to investigate the influence of the different fluorine positions in the structure on the decay time τ of the excited states. Fluorine can be integrated into the network mechanochemically via a fluorinated organic linker, here barium tetrafluoroterephthalate Ba(p-BDC-F4)2 or directly via a metal-fluorine bond (barium terephthalate fluoride BaF(p-BDC)0.5). The CP with a metal-fluorine bond shows the highest lifetime of the excited states of lanthanides (Eu3+, Tb3+ or Eu3+& Tb3+). The excitation of the lanthanides can be performed directly via the excitation wavelength typical for lanthanides and via the excitation wavelength of the linker. This enabled the simultaneous excitation of Eu3+ and Tb3+ in one CP. In the emission spectra (λem = 393 nm) of the mixed doped CPs (Eu3+ and Tb3+) the bands of both lanthanides can be observed. The integration into the crystal lattice and the homogeneous distribution of the lanthanides in the CPs is shown by X-ray diffraction, TEM, STEM-EDS measurements and the long decay times.
KW - Alkaline earth metal coordination polymers
KW - Fluorine coordination polymers
KW - Lanthanides doped coordination polymers
KW - Luminescence
PY - 2021
DO - https://doi.org/10.1016/j.solidstatesciences.2021.106614
VL - 117
SP - 106614
PB - Elsevier Masson SAS
AN - OPUS4-52559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Misra, Archismita
T1 - Polyoxometalate Ionic Liquids (POM-ILs) as Protective Coatings for CulturalHeritage against Acid Corrosion and Biodeterioration
N2 - Corrosion of stone by acid rain anddeterioration from microbial biofilmsare challenges pertinent worldwide forindustrial or residential buildings as wellas cultural heritage artefacts, like statuesor historic buildings. One mitigationoption might be the use of thintransparent films of polyoxometalate-based ionic liquids (POM-ILs). In thisregard, different limestone samples werecoated with hydrophobic, acid resistantPOM-ILs which also have biocidalproperties.1 Exposure of the samples tosimulated acid rain showed negligiblecorrosion compared to the significantdeterioration of unprotected samples(Fig 1. Left). In addition, the biocidalproperties of the POM-ILs suppress theformation of biofilms on coated stoneslabs. The coating is mechanically stableand is not removed even by harshmechanical and chemical treatment.Following studies successfully exploredthe effectiveness of the coating againstlampenflora growing in the PommeryChampagne cellar 2 (Fig 1. Right); andthe long-term performance of POM-ILsunder outdoor environmental conditions3. So, POM-ILs are already proven topossess remarkable anticorrosion andantimicrobial properties against aerobicmicroorganisms and being water-insoluble, they don’t get leached intoaquatic ecosystem, which is extremelybeneficial from an environmentalsustainability and toxicological point ofview. The current project aims tocontinue the journey on protecting thecultural heritage, shifting focus fromstones to metals and employ functionalPOM-IL nanocoatings to prevent MIC(Microbiologically Influenced Corrosion)of cultural heritage artefacts made ofmetal or metal alloy like carbon steel,brass, cast iron or bronze. Performanceof both the coating materials and coatingtechniques via optimization of theadhesion of the nanocoating on themetallic surface on the corrosion rateand corrosion products in the MICcaused by anaerobic microorganismslike methanogenic archaea or SulphateReducing Bacteria (SRB) would betested. The objective is to establishPOM-ILs as efficient environmentallysustainable nanocoating materialsagainst biocorrosion citing the already published success stories; and sketch theongoing endeavours and prospects ofthese very efficient candidates in thecontext of MIC mitigation.
T2 - Mitigation of Microbiologically InfluencedCorrosion: Towards Scientific &Industrial Standardization (MIC-STAND)
CY - Lisbon, Portugal
DA - 24.07.2024
KW - Microbiologically influenced corrosion (MIC)
KW - Polyoxometalate Ionic Liquid
KW - Nanocoating
KW - Cultural heritage
PY - 2024
AN - OPUS4-64575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Misra, Archismita
T1 - Polyoxometalate Ionic Liquids (POMILs) as Protective Coatings for Cultural Heritage Against Acid Corrosion and Biodeterioration
N2 - Corrosion of stone by acid rain anddeterioration from microbial biofilms are challenges worldwide present forindustrial or residential buildings as wellas cultural heritage, like statues orhistoric buildings. One option is the useof thin transparent films ofpolyoxometalate-based ionic liquids(POM-ILs). Stone samples were coatedwith hydrophobic, acid resistant POM-ILs which also have biocidal properties.1Exposure of the samples to simulatedacid rain showed negligible corrosioncompared to the significant deteriorationof unprotected samples (Fig 1. Left). Inaddition, the biocidal properties of thePOM-ILs suppress the formation ofbiofilms on coated stone slabs. Thecoating is mechanically stable and is notremoved even by harsh mechanical andchemical treatment. Following studiessuccessfully explored the effectiveness ofthe coating against lampenflora growingin the Pommery Champagne cellar 2 (Fig1. Right); and the long-termperformance of POM-ILs under outdoorenvironmental conditions 3. So, POM-ILs are already proven to possessremarkable anticorrosion andantimicrobial properties against aerobicmicroorganisms and being water-insoluble, they don’t get leached intoaquatic ecosystem, which is extremelybeneficial from an environmentalsustainability and toxicological point ofview. The current project aims tocontinue the journey on protecting thecultural heritage, shifting focus fromstones to metals and employ functionalPOM-IL nanocoatings to prevent MIC(Microbiologically Influenced Corrosion)of cultural heritage artefacts made ofmetal or metal alloy like carbon steel,brass, cast iron or bronze. Performanceof both the coating materials and coatingtechniques via optimization of theadhesion of the nanocoating on themetallic surface on the corrosion rateand corrosion products in the MICcaused by anaerobic microorganismslike methanogenic archaea or SulphateReducing Bacteria (SRB) would betested. The objective would be toestablish POM-ILs as efficientenvironmentally sustainablenanocoating materials againstbiocorrosion citing the already publishedsuccess stories; and sketch the ongoingendeavours and prospects of these veryefficient candidates in the context ofbiocorrosion
T2 - International Biodeterioration and Biodegradation Symposium
CY - Berlin, Germany
DA - 09.09.2024
KW - Microbiologically influenced corrosion (MIC)
KW - Polyoxometalate Ionic Liquid
KW - Nanocoating
KW - Cultural heritage
PY - 2024
AN - OPUS4-64576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
A1 - Bhattacharya, Biswajit
A1 - Rodríguez Sánchez, Noelia
A1 - Gugin, Nikita
T1 - Advancing sustainable synthesis through in situ monitoring and industrial scale-up of mechanochemical processes
N2 - Mechanochemistry has emerged as a powerful approach for sustainable materials synthesis and processing, with significant potential to meet the UN Sustainable Development Goals. This presentation will highlight our recent advancements in understanding, monitoring, and scaling-up mechanochemical transformations, focusing on the balance between fundamental understanding of reaction mechanisms and its practical applications in energy storage and energy transfer materials.
Our research has made significant strides in elucidating the fundamental mechanisms of mechanochemical reactions. We have investigated delayed polymorphism under mechanochemical conditions, revealing new insights into the interplay between mechanical impact, thermal effects, and structural transformations in molecular crystals. By employing variable temperature ball milling, we have demonstrated unprecedented control over polymorphic forms in organic cocrystals, opening new avenues for tailoring material properties.
A central focus of our work has been the development and application of time-resolved in situ monitoring techniques for mechanochemical processes. Our research on real-time synchrotron X-ray diffraction has enabled unprecedented insights into reaction pathways and kinetics. Recently, we have successfully applied energy-dispersive X-ray diffraction for time-resolved in situ monitoring of reactive extrusion, marking a significant step towards ‘lighting up’ industrial-scale mechanochemistry.
Bridging fundamental understanding with practical applications, we have explored the mechanochemical synthesis of functional materials for energy storage and transfer, making process in the mechanochemical synthesis of highly proton-conductive metal phosphonates, demonstrating the potential of mechanochemistry to manufacture advanced materials for energy applications. Addressing the challenges of industrial scale-up, we have investigated the role of solvent polarity in mechanochemical reactions, providing valuable guidance for optimizing organic syntheses such as the Knoevenagel condensation. This work contributes to our broader efforts to develop more efficient and sustainable chemical manufacturing processes.
Looking to the future, we will discuss emerging directions in mechanochemistry, including the development of continuous flow processes and the integration of machine learning approaches for reaction prediction and optimization. As we anticipate the next decade of research, we envision mechanochemistry playing an increasingly crucial role in sustainable chemical manufacturing and materials processing, with far-reaching implications for addressing global energy and environmental challenges.
T2 - Mech’cheM 2025: New forces in Mechanochemistry Conference
CY - Montpellier, France
DA - 04.06.2025
KW - Phosphonates
KW - Biocomposites
PY - 2025
AN - OPUS4-64845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
A1 - Bhattacharya, Biswajit
A1 - Rodríguez Sánchez, Noelia
A1 - Gugin, Nikita
T1 - Mechanochemical innovations for sustainable synthesis of framework materials and industrial scaleup
N2 - Mechanochemistry has emerged as a powerful approach for sustainable materials synthesis and processing, with significant potential to meet the UN Sustainable Development Goals. This presentation will highlight our recent advancements in understanding, monitoring, and scaling-up mechanochemical synthesis of framework materials, focusing on the balance between fundamental understanding of reaction mechanisms and its practical applications in energy storage and energy transfer materials.
A central focus of our work has been the development and application of time-resolved in situ monitoring techniques for mechanochemical processes. Our research on real-time synchrotron X-ray diffraction has enabled unprecedented insights into reaction pathways and kinetics. Recently, we have successfully applied energy-dispersive X-ray diffraction for time-resolved in situ monitoring of reactive extrusion, marking a significant step towards ‘lighting up’ industrial-scale mechanochemistry.
Bridging fundamental understanding with practical applications, we have explored the mechanochemical synthesis of functional materials for energy storage and transfer, making process in the mechanochemical synthesis of highly proton-conductive metal phosphonates, demonstrating the potential of mechanochemistry to manufacture advanced materials for energy applications.
T2 - 17. international-conference für Materialchemie
CY - Edinburgh, United Kingdom
DA - 07.07.2025
KW - MOF
KW - Synchrotron
KW - ZIF
PY - 2025
AN - OPUS4-64841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
T1 - The Mechanochemical Excitation of Crystalline LiN3
N2 - Mechanochemical reactions are driven by the direct absorption of mechanical energy by a solid (often crystalline) material. Understanding how this energy is absorbed and ultimately causes a chemical transformation is essential for understanding the elementary stages of mechanochemical transformations. Using as a model system the energetic material LiN3 we here consider how vibrational energy flows through the crystal structure. By considering the compression response of the crystalline material we identify the partitioning of energy into an initial vibrational excitation. Subsequent energy flow is based on concepts of phonon–phonon scattering, which we calculate within a quasi-equilibrium model facilitated by phonon scattering data obtained from Density Functional Theory (DFT). Using this model we demonstrate how the moments (picoseconds) immediately following mechanical impact lead to significant thermal excitation of crystalline LiN3, sufficient to drive marked changes in its electronic structure and hence chemical reactivity. This work paves the way towards an ab initio approach to studying elementary processes in mechanochemical reactions involving crystalline solids.
KW - Energetic materials
KW - Ab initio simulation
KW - DFT
KW - Mechanochemistry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559310
DO - https://doi.org/10.1039/d2fd00112h
SP - 1
EP - 20
PB - Royal Society of Chemistry
AN - OPUS4-55931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Cakir, Cafer Tufan
A1 - Radtke, Martin
A1 - Haider, M. Bilal
A1 - Emmerling, Franziska
A1 - F. M. Oliveira, P.
A1 - Michalchuk, Adam
T1 - Dispersive x-ray absorption spectroscopy for time-resolved in situ monitoring of mechanochemical reactions
N2 - X-ray absorption spectroscopy (XAS) provides a unique, atom-specific tool to probe the electronic structure of solids. By surmounting long-held limitations of powder-based XAS using a dynamically averaged powder in a Resonant Acoustic Mixer (RAM), we demonstrate how time-resolved in situ (TRIS) XAS provides unprecedented detail of mechanochemical synthesis. The use of a custom-designed dispersive XAS (DXAS) setup allows us to increase the time resolution over existing fluorescence measurements from ∼15 min to 2 s for a complete absorption spectrum. Hence, we here establish TRIS-XAS as a viable method for studying mechanochemical reactions and sampling reaction kinetics. The generality of our approach is demonstrated through RAM-induced (i) bottom-up Au nanoparticle mechanosynthesis and (ii) the synthesis of a prototypical metal organic framework, ZIF-8. Moreover, we demonstrate that our approach also works with the addition of a stainless steel milling ball, opening the door to using TRIS-DXAS for following conventional ball milling reactions. We expect that our TRIS-DXAS approach will become an essential part of the mechanochemical tool box.
KW - In situ studies
KW - Dipsersive XAS
KW - Mechanochemistry
KW - Time-resolved
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567659
DO - https://doi.org/10.1063/5.0130673
SN - 1089-7690
VL - 157
IS - 21
SP - 1
EP - 12
PB - American Institute of Physics
CY - Melville, NY
AN - OPUS4-56765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mazzeo, P
A1 - Lampronti, G
A1 - Michalchuk, Adam
A1 - Belenguer, A
A1 - Bacchi, A
A1 - Emmerling, Franziska
T1 - Accurate extrinsic and intrinsic peak broadening modelling for time-resolved in situ ball milling reactions via synchrotron powder X-ray diffraction
N2 - The debate on the mechanisms which underpin mechanochemical reactions via ball mill grinding is still open. Our ability to accurately measure the microstructural (crystal size and microstrain) evolution of materials under milling conditions as well as their phase composition as a function of time is key to the in-depth understanding of the kinetics and driving forces of mechanochemical transformations. Furthermore, all ball milling reactions end with a steady state or milling equilibrium – represented by a specific phase composition and relative microstructure – that does not change as long as the milling conditions are maintained. The use of a standard sample is essential to determine the instrumental contribution to the X-ray powder diffraction (XRPD) peak broadening for time-resolved in situ (TRIS) monitoring of mechanochemical reactions under in operando conditions. Using TRIS-XRPD on a ball milling setup, coupled with low-energy synchrotron radiation, we investigated different data acquisition and analysis strategies on a silicon standard powder. The diffraction geometry and the microstructural evolution of the standard itself have been studied to model the instrumental contribution to XRPD peak broadening throughout the grinding activity. Previously proposed functions are here challenged and further developed. Importantly, we show that minor drifts of the jar position do not affect the instrumental resolution function significantly. We here report and discuss the results of such investigations and their application to TRIS-XRPD datasets of inorganic and organic ball mill grinding reactions.
KW - Mechanochemistry
KW - In situ diffraction
KW - Synchrotron radiation
KW - Sustainable chemisry
PY - 2022
DO - https://doi.org/10.1039/d2fd00104g
SP - 1
EP - 17
PB - Royal Society of Chemistry
AN - OPUS4-55932
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ravi, J.
A1 - Feiler, Torvid
A1 - Mondal, A.
A1 - Michalchuk, Adam
A1 - Reddy, C. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Chandrasekar, R.
T1 - Plastically bendable organic crystals for monolithic and hybrid micro-optical circuits
N2 - Fluorescent plastically bendable crystals are a promising alternative to silicon-based materials for fabricating photonic integrated circuits, owing to their optical attributes and mechanical compliance. Mechanically bendable plastic organic crystals are rare. Their formation requires anisotropic intermolecular interactions and slip planes in the crystal lattice. This work presents three fluorescent plastically bendable crystalline materials namely, 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-chlorophenol (SB1), 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-bromophenol (SB2), and 2-((E)-(6-Bromopyridin-2-ylimino)methyl)-4-bromophenol (SB3) molecules. The crystal plasticity in response to mechanical stress facilitates the fabrication of various monolithic and hybrid (with a tip-to-tip coupling) photonic circuits using mechanical micromanipulation with an atomic force microscope cantilever tip. These plastically bendable crystals act as active (self-guiding of fluorescence) and passive waveguides both in straight and extremely bent (U-, J-, and O-shaped) geometries. These microcircuits use active and passive waveguiding principles and reabsorbance and energy-transfer mechanisms for their operation, allowing input-selective and direction-specific signal transduction.
KW - Flexible crystals
KW - Flexible waveguide
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565302
DO - https://doi.org/10.1002/adom.202201518
SN - 2195-1071
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56530
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Silbernagl, Dorothee
A1 - Yasuda, N.
A1 - Feiler, Torvid
A1 - Sturm, Heinz
A1 - Emmerling, Franziska
T1 - An atomistic mechanism for elasto-plastic bending in molecular crystals
N2 - Mechanically flexible single crystals of molecular materials offer potential for a multitude of new directions in advanced materials design. Before the full potential of such materials can be exploited, insight into their mechanisms of action must be better understood. Such insight can be only obtained through synergistic use of advanced experimentation and simulation. We herein report the first detailed mechanistic study of elasto-plastic flexibility in a molecular solid. An atomistic origin for this mechanical behaviour is proposed through a combination of atomic force microscopy, μ-focus synchrotron X-ray diffraction, Raman spectroscopy, ab initio simulation, and computed elastic tensors. Our findings suggest that elastic and plastic bending are intimately linked and result from extensions of the same molecular deformations. The proposed mechanism bridges the gap between contested mechanisms, suggesting its applicability as a general mechanism for elastic and plastic bending in organic molecular crystals.
KW - Mechanical property
KW - Mechanical flexibility
KW - Organic crystal
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577722
DO - https://doi.org/10.1039/D2SC06470G
SN - 2041-6520
VL - 14
IS - 13
SP - 3441
EP - 3450
PB - Royal Society of Chemisty (RSC)
CY - London/Cambridge
AN - OPUS4-57772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Dey, S.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
T1 - Designing Dual Mechanical Response in Molecular Crystals through Cocrystallization
N2 - Two isomorphous crystals are reported based on a naphthylvinylpyridine coformer. The crystals are mechanically flexible and exhibit photosalient response to UV irradiation. We therefore show how multiple mechanical phenomena can be simultaneously designed into a single material by cocrystallization.
KW - Cocrystal
KW - Mechanical response
PY - 2022
DO - https://doi.org/10.1021/acs.cgd.2c00913
SN - 1528-7483
VL - 22
SP - 6838
EP - 6843
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Yasuda, N.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Mechanistic Investigation of an Elastically Flexible Organic Crystal
N2 - Mechanical flexibility in molecular crystals is a fascinating behavior with potential for developing advanced technologies. However, the phenomenon of mechanical bending is poorly understood. We explore for the first time the atomistic origin of elastic bending in a single component organic crystal using a combination of μ-focus synchrotron X-ray diffraction and ab initio simulation.
KW - Flexible crystals
KW - DFT calculation
KW - Bending mechanism
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581949
DO - https://doi.org/10.1021/acs.cgd.3c00473
SN - 1528-7483
VL - 23
IS - 9
SP - 6244
EP - 6249
PB - ACS Publications
AN - OPUS4-58194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Unintended Rate Enhancement in Mechanochemical Kinetics by Using Poly(methyl methacrylate) Jars
N2 - Time-resolved in situ (TRIS) X-ray diffraction has changed how mechanochemical transformations are studied but requires the use of X-ray transparent jars often made from poly(methyl methacrylate) (PMMA). However, using PMMA jars can alter the apparent kinetics of mechanochemical polymorphism by an order of magnitude, questioning the interpretability of established TRIS methods. Our results suggest that rate enhancement in PMMA jars may not be dominated by chemical effects of the polymer, but rather a result of different equilibrium temperatures within the jar. These features must be better understood before control over mechanochemical reactions can be achieved.
KW - Mechanochemistry
KW - Organic compounds
KW - Polymers
KW - Materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565276
DO - https://doi.org/10.1021/acs.cgd.2c01227
SN - 1528-7483
SP - 1
EP - 5
PB - ACS Publications
AN - OPUS4-56527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Ciornii, Dmitri
A1 - Hodoroaba, Vasile-Dan
A1 - Benismail, Nizar
A1 - Altmann, Korinna
T1 - Project 2: Interlaboratory Comparison on detection and quantitative assessment of microplastics by use of spectroscopic and thermo-analytical methods
N2 - Validated and standardized methods in microplastic analysis are indispensable for robust monitoring and regulation. Alongside also reference materials are urgently needed. An interlaboratory comparison (ILC) offers a powerful tool to address both these challenges. The present study aimed to compare the precision and accuracy of various methods for the detection and quantification of microplastic in a water-soluble matrix. Additionally, it evaluated the suitability of the test materials (containing environmentally relevant plastic polymers) to serve as reference materials for the microplastic analysis.
In this ILC several most used thermo-analytical and spectroscopic methods have been addressed: Pyrolysis-Gas Chromatography Mass Spectrometry (Py-GC/MS), Thermal Extraction-Desorption Gas Chromatography Mass Spectrometry (TED-GC/MS), micro-Fourier Transform Infrared Spectroscopy (µ-FTIR), and micro-Raman Spectroscopy and Laser Direct Infrared Spectroscopy (LDIR). Microplastic powders of polyethylene (PE) and polyethylene terephthalate (PET) were used to assess suitability of the test materials (microplastic tablets) for method validation and use in the ILCs. The participants were guided with a SOP how to dissolve the test samples and, depending on their selected method, either quantify the number of particles (by the spectroscopic methods) or determine the mass fraction of microplastic particles per sample (by the thermo-analytical methods).
KW - ILC
KW - Microplastic
KW - FTIR
KW - Raman
KW - TED-GC/MS
KW - Py-GC/MS
PY - 2024
SP - 1
EP - 16
AN - OPUS4-60612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
A1 - Braun, U.
T1 - Monitoring von Mikroplastik
N2 - Der Vortrag gibt einen Überblick was bei der Analyse von Mikroplastik zu beachten ist und beschreibt die Vor- und Nachteile der TED-GC/MS.
T2 - Abschlusstreffen MikroPlaTas
CY - Online meeting
DA - 23.06.2021
KW - Mikroplastik
KW - TED-GC/MS
KW - Mikroplastik-Analytik
PY - 2021
AN - OPUS4-52916
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völzke, Jule L.
A1 - Hodjat Shamami, Parya
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Zimathies, Annett
A1 - Meyer, Klas
A1 - Weller, Michael G.
T1 - High-purity corundum as support for affinity extractions from complex samples
N2 - Nonporous corundum powder, known as an abrasive material in the industry, was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices. The materials based on corundum were characterized by TEM, ESEM, BET, DLS, EDS, and zeta potential measurements. The strong Al-O-P bonds between the corundum surface and amino phosphonic acids were used to introduce functional groups for further conjugations. The common crosslinker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter was oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). This work shows that oxidized polyglycerol can be used as an alternative to glutaraldehyde. With polyglycerol, more of the model protein bovine serum albumin (BSA) could be attached to the surface under the same conditions, and lower non-specific binding (NSB) was observed. As a proof of concept, IgG was extracted with protein A from crude human plasma. The purity of the product was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A binding capacity of 1.8 mg IgG per gram of corundum powder was achieved. The advantages of corundum include the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, convenient handling, and flexible application.
KW - Corundum
KW - Sapphire
KW - Affinity chromatography
KW - Antibodies
KW - Self-assembled monolayers (SAM)
KW - Polyglycerol
KW - Dendrimer
KW - Nonspecific binding (NSB)
KW - Purification
KW - Solid-phase extraction (SPE)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559342
DO - https://doi.org/10.3390/separations9090252
VL - 9
IS - 9
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Russo, Francesco
A1 - Vogl, Jochen
A1 - Sturm, Patrick
A1 - Stephan, D.
A1 - Gluth, Gregor
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Development of a sample preparation procedure for Sr isotope analysis of Portland cements
N2 - The 87Sr/86Sr isotope ratio can, in principle, be used for provenancing of cement. However, while commercial cements consist of multiple components, no detailed investigation into their individual 87Sr/86Sr isotope ratios or their influence on the integral 87Sr/86Sr isotope ratio of the resulting cement was conducted previously. Therefore, the present study aimed at determining and comparing the conventional 87Sr/86Sr isotope ratios of a diverse set of Portland cements and their corresponding Portland clinkers, the major component of these cements. Two approaches to remove the additives from the cements, i.e. to measure the conventional 87Sr/86Sr isotopic fingerprint of the clinker only, were tested, namely, treatment with a potassium hydroxide/sucrose solution and sieving on a 11-µm sieve. Dissolution in concentrated hydrochloric acid/nitric acid and in diluted nitric acid was employed to determine the 87Sr/86Sr isotope ratios of the cements and the individual clinkers. The aim was to find the most appropriate sample preparation procedure for cement provenancing, and the selection was realised by comparing the 87Sr/86Sr isotope ratios of differently treated cements with those of the corresponding clinkers. None of the methods to separate the clinkers from the cements proved to be satisfactory. However, it was found that the 87Sr/86Sr isotope ratios of clinker and cement generally corresponded, meaning that the latter can be used as a proxy for the clinker 87Sr/86Sr isotope ratio. Finally, the concentrated hydrochloric acid/nitric acid dissolution method was found to be the most suitable sample preparation method for the cements; it is thus recommended for 87Sr/86Sr isotope analyses for cement provenancing.
KW - Cement
KW - Provenancing
KW - Sr isotopes
KW - Portland clinker
KW - Dissolution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542239
DO - https://doi.org/10.1007/s00216-021-03821-7
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - 15 (Topical collection: Analytical methods and applications in the materials and life sciences)
SP - 4379
EP - 4389
PB - Springer
CY - Berlin
AN - OPUS4-54223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
A1 - Koch, Matthias
A1 - Weller, Michael G.
T1 - Editorial: Analytical methods and applications in materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - Analysis
KW - Life sciences
KW - Analytical sciences
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nanoparticle
KW - Sensor
KW - Material sciences
KW - Pollutant
KW - Environment
KW - Method
KW - Limit of detection
KW - 150th anniversary
KW - ABC
KW - BAM
KW - Collection
KW - Editorial
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550720
DO - https://doi.org/10.1007/s00216-022-04082-8
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - Topical collection: Analytical methods and applications in the materials and life sciences
SP - 4267
EP - 4268
PB - Springer
CY - Berlin
AN - OPUS4-55072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Herrmann, Stefan
T1 - Charakterisierung zweier monoklonaler Antikörper zur Detektion von Sprengstoffen
N2 - In 2019 over 30 000 people were killed or injured by explosions caused by explosives like TNT, PETN, HMX and RDX. Therefore, highly sensitive assays for the detection of TNT are needed. In this study we compared two commercially available TNT antibodies: A1.1.1 and EW75C with a highly optimized indirect competitive ELISA based on a BSA-TNA conjugate. As a result, a precision profile for both antibodies was determined with a LOD of 170 pmol L-1 for the clone A1.1.1 and a LOD of 3,2 nmol L-1 for the clone EW75C. The measurements showed that the clone A1.1.1 is a highly sensitive antibody for the detection of TNT while the clone EW75C does show medium performance at most.
In the cross-reactivity characterization of both antibodies many substances, closely related to the structure of TNT were tested. Both antibodies showed strong cross reactivity with trinitroaniline and trinitrobenzene. For the clone A1.1.1, which is known to originate from immunization of mice with an TNP-glycine-KLH conjugate, this has to be expected. Interestingly the clone EW75C, which was not characterized yet, showed similar behavior. This suggests a TNA-conjugate as immunogen for the EW75C antibody as well. None of both antibodies showed cross-reactions to the high explosives PETN, HMX and RDX. Also, the cross-reactions of nitro musks with the antibodies were investigated. Despite their prohibition, nitro musks are still used in Asia especially and are particularly popular in India. The overall superior clone A1.1.1 showed a significant cross-reactivity to musk ambrette. For practical reasons the influence of musk ambrette on this assay when used in natural environment should be investigated.
In further experiments, the highly sensitive TNT antibody A1.1.1 was digested with papain to obtain monovalent Fab-fragments. Due to its high stability against the digestion, a custom protocol for the IgG1 subclass of mice, to which the clone A1.1.1 belongs, was developed, resulting in a quantitative digestion of the intact antibody to Fab fragments. The success of the digestion was determined with MALDI-TOF-MS and SDS-PAGE. It was shown that this protocol worked for many different antibodies of IgG1 subclass as well.
KW - TNT
KW - Trinitrotoluol
KW - Nitroaromaten
KW - Nitromoschus
KW - Duftstoffe
KW - ELISA
KW - Immunoassay
KW - Antibody
KW - Explosives
KW - Klon A1.1.1
KW - Klon EW75C
KW - Fab Fragment
KW - Kreuzreaktion
KW - Crossreactivity
KW - Precision Profile
KW - Präzisionsprofil
KW - Affinity
KW - Affinitätskonstante
KW - IC50
PY - 2020
SP - 1
EP - 113
PB - Hochschule für Technik und Wirtschaft Berlin - htw
CY - Berlin
AN - OPUS4-54556
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, Xuyang
A1 - Kumar, Sourabh
A1 - Chen, Xinren
A1 - Gault, Baptiste
A1 - Dehm, Gerhard
A1 - Hickel, Tilmann
A1 - Raabe, Dierk
T1 - Grain Boundary Transformation Induced by Boron Segregation
N2 - Boron enhances the hardenability of low-alloyed steel and reduces embrittlement at low temperatures, at parts-per-million concentration levels. Ist effectiveness arises from segregation to grain boundaries (GBs)-planar defects- between crystals-yet atomic-scale evidence remains limited.We addressed this gap by synthesizing GBs with controllable geometry and orientation, enabling reproducible comparison with and without boron segregation. Differential phase-contrast imaging directly reveals boron at iron GBs, and in-situ TEM heating (20 °C to 800 °C) allows us to track the dynamic evolution of GB structures. We found that boron segregation induces local structural changes and triggers GB phase transformations, as corroborated by calculated GB defect phase diagrams spanning broad ranges of carbon and boron content. Our findings not only bridge a gap in understanding the interplay between GB structure and chemistry but also lay the groundwork for targeted design and passivation strategies in steel, potentially transforming its resistance to hydrogen embrittlement, corrosion, and mechanical failure.
KW - Steel
KW - Defect Phases
KW - Grain Boundary
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655812
DO - https://doi.org/10.1038/s41467-025-62264-1
VL - 16
SP - 1
EP - 14
PB - Nature Communications
AN - OPUS4-65581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völzke, Jule L.
A1 - Smatty, Sarah
A1 - Döring, Sarah
A1 - Ewald, Shireen
A1 - Oelze, Marcus
A1 - Fratzke, Franziska
A1 - Flemig, Sabine
A1 - Konthur, Zoltán
A1 - Weller, Michael G.
T1 - Efficient Purification of Polyhistidine-Tagged Recombinant Proteins Using Functionalized Corundum Particles
N2 - Immobilized metal affinity chromatography (IMAC) is a widely used technique for purifying polyhistidine-tagged recombinant proteins. However, it often has practical limitations that require complex optimizations and additional steps for purification. In this study, we introduce functionalized corundum particles as a novel, efficient, and economical method for purifying recombinant proteins in a column-free format. The corundum surface is modified with amino silane APTES, followed by EDTA dianhydride, and then loaded with nickel ions. We used the Kaiser test to monitor the modification process and ICP-MS to quantify the metal-binding capacity. To evaluate the system, we used His-tagged protein A/G (PAG) mixed with bovine serum albumin (BSA). The corundum particles exhibited a binding capacity of approximately 3 mg of protein per gram of corundum or 2.4 mg per 1 mL of corundum suspension. We also examined cytoplasm obtained from different E. coli strains as an example of a complex matrix. Varying the imidazole concentration in the loading and washing buffers showed that higher concentrations during loading improved purity. Even with sample volumes as large as one liter, we successfully isolated recombinant proteins down to a concentration of 1 µg/mL. We found higher purity levels with corundum when comparing the corundum material to standard Ni–NTA agarose beads. We successfully purified His6-MBP-mSA2, a fusion protein comprising monomeric streptavidin and maltose-binding protein, from E. coli cytoplasm, demonstrating the method's applicability. We also purified SARS-CoV-2-S-RBD-His8 expressed in human Expi293F cells, confirming its suitability for mammalian cell culture supernatants. The material cost of the nickel-loaded corundum material (without regeneration) is estimated to be less than 30 cents per gram of functionalized support or 10 cents per milligram of isolated protein. Another advantage of this system is the exceptional physical and chemical stability of corundum particles. Overall, we have demonstrated that this novel material offers an efficient, robust, and cost-effective purification platform for His-tagged proteins, even in challenging, complex matrices and large sample volumes with low product concentrations. This method has potential applications in both small laboratories and large-scale industrial settings.
N2 - Die immobilisierte Metallaffinitätschromatographie (IMAC) ist eine weit verbreitete Technik zur Reinigung von rekombinanten Proteinen mit Polyhistidin-Markierung. Sie hat jedoch oft praktische Einschränkungen, die komplexe Optimierungen und zusätzliche Schritte für die Aufreinigung erfordern. In dieser Studie stellen wir funktionalisierte Korundpartikel als neuartige, effiziente und wirtschaftliche Methode zur Reinigung rekombinanter Proteine in einem säulenfreien Format vor. Die Korundoberfläche wird mit dem Aminosilan APTES und anschließend mit EDTA-Dianhydrid modifiziert und dann mit Nickelionen beladen. Wir haben den Kaiser-Test zur Überwachung des Modifizierungsprozesses und ICP-MS zur Quantifizierung der Metallbindungskapazität verwendet. Zur Charakterisierung des Systems verwendeten wir His-markiertes Protein A/G (PAG) in Kombination mit Rinderserumalbumin (BSA). Die Korundpartikel wiesen eine Bindungskapazität von etwa 3 mg Protein pro Gramm Korund oder 2,4 mg pro 1 ml Korundsuspension auf. Als Beispiel für eine komplexe Matrix untersuchten wir auch Zytoplasma, das aus verschiedenen E. coli-Stämmen gewonnen wurde. Die Variation der Imidazolkonzentration in den Lade- und Waschpuffern zeigte, dass höhere Konzentrationen beim Laden die Reinheit verbesserten. Selbst bei einem Probenvolumen von bis zu einem Liter konnten wir rekombinante Proteine von 1 µg/mL isolieren. Beim Vergleich des Korundmaterials mit Standard-Ni-NTA-Agarose-Beads stellten wir einen höheren Reinheitsgrad mit Korund fest. Wir reinigten erfolgreich His6-MBP-mSA2 aus E. coli-Zytoplasma, ein Fusionsprotein, das aus monomerem Streptavidin und Maltose-bindendem Protein besteht. Wir reinigten auch SARS-CoV-2-S-RBD-His8, das in humanen Expi293F-Zellen exprimiert wurde, und bestätigten damit die Eignung des Materials für Zellkulturüberstände von Säugetieren. Die Materialkosten für nickelbeladenen Korund (ohne Regenerierung) werden auf weniger als 30 Cent pro Gramm funktionalisierten Trägers oder 10 Cent pro Milligramm isolierten Proteins geschätzt. Ein weiterer Vorteil dieses Systems ist die außergewöhnliche physikalische und chemische Stabilität der Korundpartikel. Insgesamt haben wir gezeigt, dass dieses neuartige Material eine effiziente, robuste und kostengünstige Reinigungsplattform für His-markierte Proteine bietet, selbst bei schwierigen, komplexen Matrices und großen Probenmengen mit niedrigen Produktkonzentrationen. Diese Methode könnte sowohl in kleinen Labors als auch in der Großindustrie eingesetzt werden.
KW - Aluminum oxide
KW - Sapphire
KW - Ethylenediaminetetraacetic acid
KW - Nickel chelate
KW - EDTAD
KW - HexaHis-Tag
KW - His6
KW - 6xHis
KW - His8
KW - Bioseparation
KW - IMAC purification
KW - Immunocapture
KW - Affinity chromatography
KW - Carrier
KW - Nickel
KW - Recombinant protein
KW - Escherichia coli
KW - Bacterial lysates
KW - Cytoplasm
KW - Polishing
KW - Downstream processing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575672
DO - https://doi.org/10.3390/biotech12020031
VL - 12
IS - 2
SP - 1
EP - 18
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-57567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaufmann, Jan Ole
A1 - Brangsch, J.
A1 - Kader, A.
A1 - Saatz, Jessica
A1 - Mangarova, D. B.
A1 - Zacharias, M.
A1 - Kempf, W. E.
A1 - Schwaar, T.
A1 - Ponader, Marco
A1 - Adams, L. C.
A1 - Möckel, J.
A1 - Botnar, R. M.
A1 - Taupitz, M.
A1 - Mägdefessel, L.
A1 - Traub, Heike
A1 - Hamm, B.
A1 - Weller, Michael G.
A1 - Makowski, M. R.
T1 - ADAMTS4-specific MR-probe to assess aortic aneurysms in vivo using synthetic peptide libraries
N2 - The incidence of abdominal aortic aneurysms (AAAs) has substantially increased during the last 20 years and their rupture remains the third most common cause of sudden death in the cardiovascular field after myocardial infarction and stroke. The only established clinical parameter to assess AAAs is based on the aneurysm size. Novel biomarkers are needed to improve the assessment of the risk of rupture. ADAMTS4 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 4) is a strongly upregulated proteoglycan cleaving enzyme in the unstable course of AAAs. In the screening of a one-bead-one-compound library against ADAMTS4, a low-molecular-weight cyclic peptide is discovered with favorable properties for in vivo molecular magnetic resonance imaging applications. After identification and characterization, it’s potential is evaluated in an AAA mouse model. The ADAMTS4-specific probe enables the in vivo imaging-based prediction of aneurysm expansion and rupture.
KW - Peptide
KW - Peptide library
KW - OBOC library
KW - Combinatorial chemistry
KW - Peptide aptamers
KW - Binding molecule
KW - Affinity
KW - Synthetic peptides
KW - Contrast agent
KW - Magnetic resonance imaging
KW - One-bead-one-compound library
KW - On-chip screening
KW - Lab-on-a-chip
KW - MALDI-TOF MS
KW - SPR
KW - Surface plasmon resonance
KW - Alanine scan
KW - Fluorescence label
KW - MST
KW - Docking
KW - Chelate
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560930
DO - https://doi.org/10.1038/s41467-022-30464-8
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
VL - 13
IS - 1
SP - 1
EP - 18
PB - Springer Nature Limited
CY - Heidelberg
AN - OPUS4-56093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - A Self-Driving Lab for Nano and Advanced Materials Synthesis in a Self-Driving Lab
N2 - In this contribution, we present our Self-Driving Lab (SDL) for Nano and Advanced Materials, that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nanomaterials – with automated characterization and data analysis, for a complete and reliable nanomaterial synthesis workflow. By fully automating the processing steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. The system also exhibits high modularity and adaptability in terms of reaction scales and incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence). We discuss the excellent reproducibility of the various materials synthesized on the platform in terms of particle size and size distribution, and the adaptability and modularity that allows access to a diverse set of nanomaterial classes.
We also present several key aspects of the central backend that orchestrates the (parallelized) syntheses workflows. One key feature is the resource management or “traffic control” for scheduling and executing parallel reactions in a multi-threaded environment. Another is the interface with data analysis algorithms from in-line, at-line, and off-line measurements. Here, we will give examples of how automatic image segmentation of electron microscopy images with the help of AI can be used for reducing the “data analysis bottleneck” from an off-line measurement. We will also discuss various machine learning (ML) algorithms that are currently implemented in the backend and can be used for ML-guided, closed-loop material optimization in our SDL. Lastly, we will show our recent efforts in making the workflow generation on SDLs more user-friendly by using large language models to generate executable workflows automatically from synthesis procedures given in natural language and user-friendly graphical user interfaces based on node editors that also allow for knowledge graph extraction from the workflows. In this context, we are currently also working on a common description or ontology for representing the process steps and parameters of the workflows, which will greatly facilitate the semantic description and interoperability of workflows between different SDL hardware and software platforms.
T2 - Series on Digitalisation-Meet the Experts | Special Topic: Automation
CY - Berlin, Germany
DA - 27.02.2026
KW - Self-Driving Labs
KW - Materials Acceleration Platforms
KW - Advanced Materials
KW - Nanomaterials
KW - Automation
KW - Digitalization
PY - 2026
AN - OPUS4-65604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Döring, Sarah
T1 - Corundum Particles as Trypsin Carrier for Efficient Protein Digestion
N2 - This dataset contains raw LC–MS/MS files of trypsin-digested NISTmAb acquired on a SCIEX TripleTOF 6600 mass spectrometer in DIA (SWATH) mode for antibody quantification. In addition, it includes MALDI-TOF MS peptide mass fingerprints of trypsin-digested Herceptin as well as reference spectra that can be used for antibody identification using the open-source software ABID 2.0 (https://bam.de/ABID).
The data were generated within a study demonstrating the applicability of corundum-immobilized trypsin for antibody digestion and its suitability for peptide-based LC–MS/MS quantification and MALDI-TOF MS fingerprinting–based antibody identification.
KW - NISTmAb
KW - Herceptin
KW - MALDI-TOF MS peptide mass fingerprint
KW - ABID 2.0
PY - 2025
DO - https://doi.org/10.5281/zenodo.17416536
PB - Zenodo
CY - Geneva
AN - OPUS4-65365
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Döring, Sarah
T1 - Vergleichende Darstellung SARS-CoV-2-spezifischer Nanobodys aus unterschiedlichen Wirtsorganismen
N2 - Aufgrund der anhaltenden COVID-19-Pandemie werden neutralisierende Therapeutika benötigt. Eine Möglichkeit zur Behandlung stellt die Verwendung monoklonaler Anti-SARS-CoV-2-Immun-globuline dar. Ihre Produktion in Säugetierzellen ist jedoch schwer skalierbar, um den weltweiten Bedarf zu decken. VHH-Antikörper, auch Nanobodys genannt, bieten hierfür eine Alternative, da sie eine hohe Temperaturstabilität aufweisen und eine kostengünstige Produktion in prokaryotischen Wirtsorganismen ermöglichen.
KW - E. coli
KW - Corona
KW - Virus
KW - Spike-Protein
KW - Nanobody
KW - Antikörper
KW - Expression
KW - Fingerprint
KW - Vhh
KW - RBD
KW - COVID-19
KW - SARS-CoV-2
KW - ELISA
KW - MST
KW - Halomonas elongata
KW - Periplasma
KW - SDS-PAGE
KW - ACE2-Rezeptor
PY - 2021
SP - 1
EP - 111
PB - Technische Universität Berlin
CY - Berlin
AN - OPUS4-54624
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völzke, Jule L.
T1 - Corundum as a novel affinity platform for the isolation of human IgG from plasma
N2 - Nonporous corundum powder was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices.The common crosslinker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter was oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). As a proof of concept, IgG was extracted with protein A from crude human plasma. The advantages of corundum include the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, convenient handling, and flexible application.
T2 - Adlershofer Forschungsforum 2022
CY - Berlin, Germany
DA - 11.11.2022
KW - Affinity support
KW - Affinity chromatography
KW - Affinity extraction
KW - Phosphonic acids
KW - Polyglycerol
KW - Reductive amination
KW - Amino acid analysis
KW - Tyrosine
KW - Protein quantification
KW - SDS-PAGE
KW - Antibodies
KW - Antibody purification
KW - Downstream processing
KW - Bovine serum albumin
KW - BSA
KW - Protein a
KW - TEM
KW - ESEM
KW - Aluminum oxide
KW - Sapphire
KW - Human plasma
KW - Protein immobilization
KW - Protein hydrolysis
KW - Glutaraldehyde
KW - Aromatic amino acid analysis AAAA
PY - 2022
AN - OPUS4-56154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Völzke, Jule L.
A1 - Hodjat Shamami, Parya
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Zimathies, Annett
A1 - Weller, Michael G.
T1 - High-purity corundum as support for affinity extractions from complex samples
N2 - Nonporous corundum powder, known as an abrasive material in the industry, was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices. The materials based on corundum were characterized by TEM, ESEM, BET, DLS, and zeta potential measurements. The strong Al-O-P bonds between the corundum surface and amino phosphonic acids are used to introduce functional groups for further conjugations. The common cross-linker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter is oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). This work shows that oxidized polyglycerol can be used as an alternative to glutaraldehyde. With polyglycerol, more of the model protein bovine serum albumin (BSA) could be attached to the surface under the same conditions, and lower nonspecific binding (NSB) was observed. As a proof of concept, IgG was extracted with protein A from crude human plasma. The purity of the product was examined by SDS-PAGE. A binding capacity of 1.8 mg IgG per g of corundum powder was achieved. The advantages of corundum are the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, and flexible application.
KW - Protein
KW - Bioseparation
KW - Purification
KW - Immunoprecipitation
KW - Affinity chromatography
KW - Polyglycerol
KW - Glutaraldehyde
KW - Linker
KW - Bioconjugation
KW - Self-assembled monolayer (SAM)
KW - Periodate oxidation
KW - Reductive amination
KW - Antibodies
KW - Igg
KW - Immunoglobulins
KW - Carrier
KW - Solid phase
KW - Hyperbranched polymer
KW - Aromatic amino acid analysis aaaa
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555142
DO - https://doi.org/10.20944/preprints202208.0004.v1
SN - 2310-287X
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frechilla, A.
A1 - Martínez, E.
A1 - del Moral, J.
A1 - López-Santos, C.
A1 - Frechilla, J.
A1 - Nuñez-Gálvez, F.
A1 - López-Flores, V.
A1 - de la Fuente, G.F.
A1 - Hülagü, Deniz
A1 - Bonse, Jörn
A1 - González-Elipe, A.R.
A1 - Borrás, A.
A1 - Angurel, L.A.
T1 - Influence of near-edge Laser-Induced Periodic Surface Structures (LIPSS) on the electrical properties of fs-laser-machined ITO microcircuits
N2 - Scalable, cost-effective methods for processing transparent electrodes at the microscale are pivotal to advancing in electrochemistry, optoelectronics, microfluidics, and energy harvesting. In these fields, the precise fabrication of micrometric circuits and patterns plays a critical role in determining device performance, material compatibility, and integration with added-value substrates. In this context, Laser Subtractive Manufacturing stands out as a suitable microfabrication technique for its adaptability to diverse materials and complex configurations, as well as its straightforward scalability, affordability, and eco-friendly nature. However, a challenge in micromachining metals and metal oxides is the inherent formation of Laser-Induced Periodic Surface Structures (LIPSS), which can significantly impair electrical conductivity, particularly when circuit dimensions fall within the micrometer range. Herein, we investigate the micromachining of electrical microcircuits using ultrashort pulse laser systems applied to transparent indium tin oxide (ITO) thin films. We analyze the formation of LIPSS at the edges of the micromachined regions associated with the Gaussian distribution of the energy within the laser spot, and the impact of these structures on the electrical properties of the circuits. Thus, we systematically evaluate the influence of LIPSS orientation and periodicity by fabricating various circuit patterns using femtosecond lasers at green (515 nm) and ultraviolet (UV) (343 nm) wavelengths. A correlation between electrical resistivity measurements and microstructure analysis, as determined by field emission scanning electron and transmission electron microscopy, reveals distinct effects of the formed nanostructures depending on the laser source and its polarization. For the green wavelength, the edge side regions where LIPSS are oriented perpendicular to the ITO track exhibit a resistance higher by a factor just above two compared to those where LIPSS are parallel. Additionally, UV laser processing results in a pronounced reduction of ITO thickness at the boundary between the LIPSS region and the substrate. The mechanisms for the formation of LIPSS with both wavelengths are also discussed. Furthermore, we have determined that in narrow conductive tracks with a width ranging from 6 to 8 µm, the impact of LIPSS is particularly significant because the LIPSS structured region occupies a dominant fraction of the total width.
KW - ITO
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser subtractive manufacturing
KW - fs-laser processing
KW - Electrical properties
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655921
DO - https://doi.org/10.1016/j.apsusc.2026.166415
SN - 0169-4332
VL - 731
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Juds, Carmen
A1 - Schmidt, J.
A1 - Weller, Michael G.
A1 - Lange, Thorid
A1 - Beck, Uwe
A1 - Conrad, T.
A1 - Boerner, H. G.
T1 - Combining phage display and next-generation sequencing for materials sciences: A case study on probing polypropylene surfaces
N2 - Phage display biopanning with Illumina next-generation sequencing (NGS) is applied to reveal insights into peptide-based adhesion domains for polypropylene (PP). One biopanning round followed by NGS selects robust PP-binding peptides that are not evident by Sanger sequencing. NGS provides a significant statistical base that enables motif analysis, statistics on positional residue depletion/enrichment, and data analysis to suppress false-positive sequences from amplification bias. The selected sequences are employed as water-based primers for PP-metal adhesion to condition PP surfaces and increase adhesive strength by 100% relative to nonprimed PP.
KW - Polymers
KW - Polypropylene
KW - Glue
KW - Plastics
KW - Surface Activation
KW - Primer
KW - Peptide Library
KW - Epoxy
KW - Solid-binding Peptides
KW - Functionalization
KW - Polymer-binding Peptides
KW - Adhesion
KW - Material-binding Peptides
KW - Adhesives
PY - 2020
DO - https://doi.org/10.1021/jacs.0c03482
SN - 0002-7863
SN - 1520-5126
VL - 142
IS - 24
SP - 10624
EP - 10628
PB - ACS
CY - Washington, DC, USA
AN - OPUS4-51123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Portela, Raquel
A1 - Barbero, Francesco
A1 - Breuninger, Esther
A1 - Camassa, Laura Maria Azzurra
A1 - Velickovic, Tanja Cirkovic
A1 - Charitidis, Costas
A1 - Costa, Anna
A1 - Fadda, Marta
A1 - Fengler, Petra
A1 - Fenoglio, Ivana
A1 - Giovannozzi, Andrea M.
A1 - Haugen, Øyvind Pernell
A1 - Kainourgios, Panagiotis
A1 - von der Kammer, Frank
A1 - Kirchner, Markus J.
A1 - Lomax-Vogt, Madeleine
A1 - Lujic, Tamara
A1 - Milczewski, Frank
A1 - Moussawi, Mhamad Aly
A1 - Ortelli, Simona
A1 - Parac-Vogt, Tatjana N.
A1 - Potthoff, Annegret
A1 - Reinosa, Julian J.
A1 - Röschter, Sophie
A1 - Sacco, Alessio
A1 - Wimmer, Lukas
A1 - Zanoni, Ilaria
A1 - Dailey, Lea Ann
T1 - Characterizing nanoplastic suspensions of increasing complexity: Inter-laboratory comparison of size measurements using dynamic light scattering
N2 - Understanding the potential human health risks associated with micro- and nanoplastic exposure is currently a priority research area. Nanoplastic toxicity studies are complicated by the lack of available, well-characterized test and reference materials. Further, many nanoplastic test materials are inherently more polydisperse and heterogenous in shape compared to polystyrene beads, making accurate and representative size distribution measurements particularly challenging. The aim of this study was to conduct an inter-laboratory comparison of dynamic light scattering measurements, the most commonly used particle sizing method for nanomaterials. Using a published standard operating procedure, size measurements in water and a standardized cell culture medium (CCM) were generated for spherical, carboxy-functionalized polystyrene nanoparticles (PS-COOH; 50 nm; benchmark material), and for increasingly complex in-house produced spherical poly(ethylene terephthalate) (nanoPET) and irregular shaped polypropylene (nanoPP) test materials. The weighted mean of hydrodynamic diameters of PS-COOH dispersed in water (55 ± 5 nm) showed moderate variation between labs (coefficient of variation, CV = 8.2%) and were similar to literature reports. Measurements of nanoPET (82 ± 6 nm) and nanoPP (182 ± 12 nm) in water exhibited similar CV values (nanoPET: 7.3% and nanoPP; 6.8%). Dispersion of PS-COOH and nanoPET in CCM increased the CV to 15.1 and 14.2%, respectively, which is lower than literature reports (CV = 30%). We conclude with a series of practical recommendations for robust size measurements of nanoplastics in both water and complex media highlighting that strict adherence to a standard operating procedure is required to prevent particle agglomeration in CCM
KW - Nanoplastics
KW - Reference materials
KW - Polypropylene
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644571
DO - https://doi.org/10.1039/d5en00645g
SN - 2051-8153
SP - 1
EP - 15
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Validation of microplastics detection methods and proficiency testing: Suitable microplastic reference materials for interlaboratory comparison
N2 - Since microplastics (MPs) can be found everywhere and are becoming a problem of high concern, it is necessary to understand their physico-chemical properties. To obtain reliable analytical data a set of validated methods for sampling, sample preparation, detection, and data evaluation are needed.
To meet these needs an interlaboratory comparison (ILC) with 84 participants worldwide has been organized under the international pre-standardisation platform VAMAS (www.vamas.org/twa45/) as Project 2 “Development of standardized methodologies for characterisation of microplastics with microscopy and spectroscopy methods” within the Technical Working Area TWA 45 “Micro and Nano Plastics in the Environment”. In this ILC thermo-analytical methods (Py-GC/MS and TED-GC/MS) and vibrational methods (µ-Raman and µ-FTIR) have been tested and compared by providing a set of microplastic representative test materials and measurement protocols developed at BAM. The defined measurands were: particle number concentration, particle size distribution (PSD), and polymer identity and mass content. To increase the statistical quality, 6 samples were shipped together with blank samples. Hence, the ILC provides information on precision and accuracy of the results obtained with different methods as well as strengths and limitations of the proposed protocols.
T2 - SETAC 34th Meeting
CY - Seville, Spain
DA - 05.05.2024
KW - ILC
KW - Microplastic
KW - Method validation
KW - Stakeholder
KW - Reference materials
KW - Polyethylene
KW - Polyethylene Terephtalate
PY - 2024
AN - OPUS4-60039
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Alasonati, E
A1 - Bartczak, D
A1 - Altmann, Korinna
A1 - Giovannozzi, A
T1 - Towards Standardised Micro and Nanoplastics Analysis via Interlaboratory Comparisons: First Outlook of the VAMAS TWA 45 P3 Project
N2 - This talk is part of the stakeholder workshop of the PlasticTrace project held in September 2025 in Oslo. The presentation shows first results of the VAMAS ILC on nanoplastics. PP nanoparticles were given to the participants. These were asked to measure the mass or particle number or size of the PP nanoplastics. Various techniques such as DLS, FFF, Py-GC/MS, TED-GC/MS, PTA were used.
T2 - Stakeholder Workshop PlasticsTrace
CY - Online meeting
DA - 09.09.2025
KW - Nanoplastics
KW - ILC
KW - DLS
KW - Polypropylene
PY - 2025
AN - OPUS4-64714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Micro and Nano Plastics in the Environment
N2 - The VAMAS/TWA 45 Project 2 “Development of standardized methodologies for characterisation of microplastics with microscopy and spectroscopy methods” involving 85 participants around the world is primarily discussed with respect to the results received and a first data evaluation. Status of the Project "Guidelines for defining reference materials for plastic degradation in marine environment" is reported and two new project proposals are presented: "Development of standardized methodologies for characterisation of nanoplastics (starting soon, BAM as leader?) and "Development of analytical protocols for the identification and quantification of microplastics of fibrous shape (still in negotiation)".
T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 48th Steering Committee Meeting
CY - New Delhi, India
DA - 09.10.2023
KW - Microplastics
KW - Nanoplastics
KW - Interlaboratory comparison
KW - VAMAS
KW - Reference materials
KW - ISO
PY - 2023
UR - https://www.nplindia.org/index.php/amcsnzt_2023/
AN - OPUS4-58539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Casali, Lucia
A1 - Carta, Maria
A1 - Michalchuk, Adam
A1 - Delogu, Francesco
A1 - Emmerling, Franziska
T1 - Kinetics of the mechanically induced ibuprofen–nicotinamide co-crystal formation by in situ X-ray diffraction
N2 - Mechanochemistry is drawing attention from the pharmaceutical industry given its potential for sustainable material synthesis and manufacture. Scaling mechanochemical processes to industrial level remains a challenge due to an incomplete understanding of their underlying mechanisms. We here show how time-resolved in situ powder X-ray diffraction data, coupled with analytical kinetic modelling, provides a powerful approach to gain mechanistic insight into mechanochemical reactions. By using the ibuprofen–nicotinamide co-crystal mechanosynthesis as a benchmark system, we investigate the behaviour of the solids involved and identify the factors that promote the reaction. As mechanochemical mechanisms become increasingly clear, it promises to become a breakthrough in the industrial preparation of advanced pharmaceuticals.
KW - Mechanochemistry
KW - Kinetics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608820
DO - https://doi.org/10.1039/D4CP01457J
SN - 1463-9084
VL - 26
SP - 22041
EP - 22048
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-60882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Misra, Archismita
T1 - Polyoxometalate Ionic Liquids as Protective Coatings for Industrial Infrastructure and Cultural Heritage against Microbiologically Influenced Corrosion (MIC)
N2 - Corrosion of stone and metal due to acid rain and biodeterioration poses significant challenges for industrial and residential infrastructure, as well as cultural heritage, including statues and historical artefacts. A promising mitigation strategy involves thin, transparent films of polyoxometalate-based ionic liquids (POM-ILs) as chemical shields. Stone samples coated with acid-resistant, biocidal POM-ILs exhibited negligible corrosion when exposed to simulated acid rain, in stark contrast to the severe deterioration of unprotected samples. Additionally, their biocidal properties effectively prevent biofilm formation on coated surfaces. Following studies successfully explored the effectiveness of the coating against lampenflora growing in the Pommery Champagne cellar; and the long-term performance of POM-ILs under outdoor environmental conditions. So, POM-ILs have already demonstrated remarkable anticorrosion and antimicrobial properties against aerobic microorganisms and, being water-insoluble, do not leach into aquatic ecosystem. The current research project repurposes the POM-ILs, extending their application to metals, specifically targeting microbiologically influenced corrosion (MIC) in cultural heritage artefacts made of brass, carbon steel, cast iron, and bronze. This involves optimizing nanocoating adhesion to the metal surface and evaluating its protective efficacy against MIC caused by anaerobic microorganisms such as methanogenic archaea and sulfate reducing bacteria (SRB). This presentation will highlight POM-ILs as sustainable, high-performance nanocoatings for biocorrosion mitigation. It will showcase published success stories, discuss ongoing research and proof-of-concept results, and explore future prospects for these advanced materials in safeguarding metal infrastructure and artefacts across different industrial sectors as well as in the context of cultural heritage conservation.
T2 - 10th International symposium on applied microbiology and molecular biology in oil systems (ISMOS10)
CY - Nashville, Tennessee, USA
DA - 11.08.2025
KW - Polyoxometalates
KW - Corrosion
KW - Microbiologically Influenced Corrosion
KW - Ionic Liquid
PY - 2025
AN - OPUS4-64548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Production of reference materials using a quality by design approach
N2 - Accurate analysis of microplastics is based on validated methods and the use of standardized protocols. Therefore, reference materials are essential to determine recovery rates and optimise the existing workflows. The reference materials should mimic the reality in terms of particle properties and concentration and are intended for a special use. The Quality-by-Design approach helps to select the users need and defines a target product profile with mandatory and desired particle properties. We will address different reference material top-down production processes with their limits and challenges for production of materials varying in size ranges of micro- and nanoplastics.
T2 - OECD Workshop on Nanoplastics
CY - Paris, France
DA - 12.11.2025
KW - Microplastics
KW - Reference materials
KW - Nanoplastics
KW - Quality-by-Design
PY - 2025
AN - OPUS4-64717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - Researching automation of gypsum recycling
N2 - This poster illustrates the recent work on a setup for automated in-situ analysis of gypsum recycling processes. Analysis in synchrotron X-rays, Raman- and UV-vis spectroscopy are made possible with this compact and mobile setup. First results from Raman spectroscopy on the conversion of gypsum to bassanite in hypersaline solutions are presented and future plans on optimization are formulated.
T2 - ANAKON 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Recycling
KW - Automation
KW - Synchrotron-X-ray-diffraction
KW - Raman-spectroscopy
KW - Gypsum
PY - 2025
AN - OPUS4-62706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hemingway, Jack M.
A1 - Quayle, Heather M.
A1 - Byrne, Cian
A1 - Pulham, Colin R.
A1 - Mondal, Subrata
A1 - Michalchuk, Adam
A1 - Morrison, Carole A.
T1 - Predicting impact sensitivities for an extended set of energetic materials via the vibrational up-pumping model: Molecular-based structure–property relationships identified
N2 - We have applied the vibrational up-pumping model to predict the mechanically-induced impact sensitivities of 33 molecular energetic crystals. Overall, the current model successfully identifies and ranks the compounds that are most sensitive to mechanical initiation, but offers poorer differentiation between compounds with lower sensitivity. Further developments to include the effects of trigger bond activation led to significant improvements in predictive capability. We show that this structure–property model highlights the importance of molecular flexibility in predicting impact sensitivity, and furthermore, we show that the Kier molecular flexibility index, which can be obtained from a SMILES string, offers a simple molecular-based descriptor that goes some way towards predicting the sensitivity of energetic materials.
KW - Vibrational
KW - Pyrazoles
KW - Comprising
KW - Electronic
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632651
DO - https://doi.org/10.1039/d5cp00852b
SN - 1463-9076
VL - 27
IS - 22
SP - 11640
EP - 11648
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-63265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghiringhelli, Luca M.
A1 - Baldauf, Carsten
A1 - Bereau, Tristan
A1 - Brockhauser, Sandor
A1 - Carbogno, Christian
A1 - Chamanara, Javad
A1 - Cozzini, Stefano
A1 - Curtarolo, Stefano
A1 - Draxl, Claudia
A1 - Dwaraknath, Shyam
A1 - Fekete, Ádám
A1 - Kermode, James
A1 - Koch, Christoph T.
A1 - Kühbach, Markus
A1 - Ladines, Alvin Noe
A1 - Lambrix, Patrick
A1 - Himmer, Maja-Olivia
A1 - Levchenko, Sergey V.
A1 - Oliveira, Micael
A1 - Michalchuk, Adam
A1 - Miller, Ronald E.
A1 - Onat, Berk
A1 - Pavone, Pasquale
A1 - Pizzi, Giovanni
A1 - Regler, Benjamin
A1 - Rignanese, Gian-Marco
A1 - Schaarschmidt, Jörg
A1 - Scheidgen, Markus
A1 - Schneidewind, Astrid
A1 - Sheveleva, Tatyana
A1 - Su, Chuanxun
A1 - Usvyat, Denis
A1 - Valsson, Omar
A1 - Wöll, Christof
A1 - Scheffler, Matthias
T1 - Shared metadata for data-centric materials science
N2 - The expansive production of data in materials science, their widespread sharing and repurposing requires educated support and stewardship. In order to ensure that this need helps rather than hinders scientific work, the implementation of the FAIR-data principles (Findable, Accessible, Interoperable, and Reusable) must not be too narrow. Besides, the wider materials-science community ought to agree on the strategies to tackle the challenges that are specific to its data, both from computations and experiments. In this paper, we present the result of the discussions held at the workshop on “Shared Metadata and Data Formats for Big-Data Driven Materials Science”. We start from an operative definition of metadata, and the features that a FAIR-compliant metadata schema should have. We will mainly focus on computational materials-science data and propose a constructive approach for the FAIRification of the (meta)data related to ground-state and excited-states calculations, potential-energy sampling, and generalized workflows. Finally, challenges with the FAIRification of experimental (meta)data and materials-science ontologies are presented together with an outlook of how to meet them.
KW - Library and Information Sciences
KW - Statistics, Probability and Uncertainty
KW - Computer Science Applications
KW - Education
KW - Information Systems
KW - Statistics and Probability
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584846
DO - https://doi.org/10.1038/s41597-023-02501-8
VL - 10
IS - 1
SP - 1
EP - 18
PB - Springer Science and Business Media LLC
AN - OPUS4-58484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Speight, Isaiah R.
A1 - Ardila-Fierro, Karen J.
A1 - Hernández, José G.
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
A1 - García, Felipe
A1 - Colacino, Evelina
A1 - Mack, James
T1 - Ball milling for mechanochemical reactions
N2 - Mechanochemistry is an emerging field with the potential to pave the way for sustainable chemistry. Although the use of mechanical force to initiate chemical reactions has been recognized for millennia, it has often taken a backseat to thermal and photonic methods. Over the past 30 years, mechanochemistry has seen a resurgence of interest, attracting researchers across the globe. Despite its proven ability to address numerous challenges within the chemical community, mechanochemistry remains on the periphery. This Primer serves as a valuable guide for conducting mechanochemical reactions by ball milling, offering an overview of the processes, methods, tools and terminology necessary to embark on research in this field. It also highlights persistent hurdles such as equipment standardization, understanding the impact of new discoveries and the lack of predictability of reaction outcomes. The Primer’s focus is on how mechanochemical ball milling is used in various chemical transformations, distinguishing it from other forms of mechanochemistry discussed in the literature. With a promising future, this Primer serves as a gateway for those aspiring to contribute to the field’s advancement.
KW - Mechanochemistry
KW - Ball milling
KW - Upscaling
PY - 2025
DO - https://doi.org/10.1038/s43586-025-00401-2
SN - 2662-8449
VL - 5
IS - 1
SP - 1
EP - 18
PB - Springer Science and Business Media LLC
AN - OPUS4-63447
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
T1 - On the physical processes of mechanochemically induced transformations in molecular solids
N2 - Initiating or sustaining physical and chemical transformations with mechanical force – mechanochemistry – provides an opportunity for more sustainable chemical processes, and access to new chemical reactivity.
KW - Molecular solids
KW - Transformation
KW - Destabilisation
KW - Instabilities
KW - Common phenomenon
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621755
DO - https://doi.org/10.1039/d4cc04062g
IS - 99
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62175
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Driscoll, Laura L.
A1 - Driscoll, Elizabeth H.
A1 - Dong, Bo
A1 - Sayed, Farheen N.
A1 - Wilson, Jacob N.
A1 - O’Keefe, Christopher A.
A1 - Gardner, Dominic J.
A1 - Grey, Clare P.
A1 - Allan, Phoebe K.
A1 - Michalchuk, Adam
A1 - Slater, Peter R.
T1 - Under pressure: offering fundamental insight into structural changes on ball milling battery materials
N2 - Synthesis of Li ion battery materials via ball milling has been a huge area of growth, leading to new high-capacity electrode materials, such as a number of promising disordered rocksalt (DRS) phases. In prior work, it was generally assumed that the synthesis was facilitated simply by local heating effects during the milling process. In this work, we show that ball milling Li2MoO4 leads to a phase transformation to the high pressure spinel polymorph and we report electrochemical data for this phase. This observation of the formation of a high pressure polymorph shows that local heating effects alone cannot explain the phase transformation observed (phenakite to spinel) and so indicates the importance of other effects. In particular, we propose that when the milling balls collide with the material, the resulting shockwaves exert a localised pressure effect, in addition to local heating. To provide further support for this, we additionally report ball milling results for a number of case studies (Li2MnO3, Li2SnO3, Nb2O5) which reinforces the conclusion that local heating alone cannot explain the phase transformations observed. The work presented thus provides greater fundamental understanding of milling as a synthetic pathway and suggests potential strategies to prepare such samples without milling (e.g., doping to create internal chemical pressure). In addition, we suggest that further research is needed into the effect of the use of milling as a route to smaller particles, since we believe that such milling may also be affecting the surface structure of the particles through the influence of the shockwaves generated.
KW - Pollution
KW - Nuclear Energy and Engineering
KW - Sustainability and the Environment
KW - Environmental Chemistry
KW - Renewable Energy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590086
DO - https://doi.org/10.1039/d3ee00249g
VL - 16
IS - 11
SP - 5196
EP - 5209
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Delogu, Francesco
T1 - Fundamental basis of mechanochemical reactivity
N2 - This themed collection includes a collection of articles on the fundamental basis of mechanochemical reactivity.
KW - Mechanochemical
KW - Metal-organic
KW - Transformation
KW - Dimerization
PY - 2024
DO - https://doi.org/10.1039/d4cp90153c
SP - 1
EP - 3
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61500
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
A1 - Casali, Lucia
A1 - May, Anastasia
T1 - Real-Time Monitoring and Temperature Control for Optimized Polymorph Engineering
N2 - Integrating real-time monitoring with precise temperature control and mechanochemical processing represents a transformative approach to the controlled engineering of polymorphic forms in molecu-lar solids. Combining these methodologies overcomes the limitations of traditional solution-based or purely thermal approaches, enabling access to metastable or otherwise elusive polymorphs under milder and more sustainable conditions. Recent studies have shown that mechanochemical trans-formations proceed through distinct kinetic stages, including prolonged induction periods that can be tuned by adjusting the mechanical energy input[1]. These induction periods are associated with pro-cesses of mechanical activation, such as the accumulation of defects and increased surface energy, which lower the effective energy barriers for polymorphic transitions. Crucially, it is the total accumu-lated mechanical energy, rather than the duration or intensity of milling alone, that dictates the onset of polymorphic conversion, offering a new dimension of kinetic control[2-5].
Variable temperature ball milling reveals that the temperature required to induce polymorphic trans-formations can be significantly lower than under conventional thermal methods. For instance, tran-sitions that typically require high temperatures under equilibrium conditions can be achieved at sub-stantially lower temperatures in the presence of mechanical activation. This has been demonstrated in cocrystal systems such as nicotinamide-pimelic acid and isonicotinamide-glutaric acid, where the transition temperature was lowered by up to 25°C[2,3]. Real-time, in situ powder X-ray diffraction and temperature monitoring are essential for capturing transient phases and elucidating the interplay between thermal and mechanical effects. This confirms that combining mechanical energy with con-trolled temperature not only accelerates transformation kinetics, but also expands the accessible polymorphic landscape [2,3].
Collectively, these advances underscore the potential of real-time monitored, temperature-controlled mechanochemistry as a robust platform for the selective design and manufacturing of polymorphs. This approach provides unprecedented control over solid-state reactivity and opens new avenues for the sustainable and targeted engineering of functional materials and pharmaceuticals.
T2 - 13th Bologna´s convention on Crystal Forms - CF@Bo n.13 University of Bologna
CY - Bologna, Italy
DA - 07.09.2025
KW - Plymorhism
KW - Pre-activation
PY - 2025
AN - OPUS4-64839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Kittner, Maria
A1 - Altmann, Korinna
A1 - Hamann, Sven
A1 - Weyer, Rüdiger
A1 - Kalbe, Ute
T1 - Bewertung der Freisetzung von Mikroplastik aus Sportböden auf Kunststoffbasis - Abschlussbericht
N2 - Die Europäische Kommission hat 2023 ein Verbot zum bewussten Austrag von Mikroplastik (MP) in die Umwelt beschlossen, das auch für die Verwendung von synthetischen Gummi-Granulaten (v. a. EPDM) in Sportböden gilt. In Deutschland gibt es laut DFB ca. 5100 Kunstrasenplätze. In der EU beläuft sich die Anzahl laut ECHA auf 13,000 Kunstrasen- und 47,000 Bolzplätze, Tendenz steigend. Das Hauptziel des Projektes war es daher, eine Massenbilanz für die Freisetzung von MP zu erstellen, um so eine Schätzung des MP-Austrags pro Kunstrasenplatz und Jahr zu ermöglichen. Dafür werden die MP-Emissionen von drei Kunstrasenszenarien in verschiedenen Zuständen (ungealtert, künstlich gealtert und in Echtzeit gealtert) verglichen: die Vergangenheit (Kunstrasen: fossilbasiert, EPDM-Füllung), die Gegenwart (der in Europa am häufigsten installierte Rasen) und die Zukunft (Rasen mit recycelten Grasfasern, keine synthetische Füllung sondern z.B. Quarzsand oder Korkschrott). Dazu werden fabrikneue Kunststoffrasen und EPDM-Granulat unter Laborbedingungen beschleunigt gealtert, um die Freiland-Beanspruchung eines Kunststoffrasens in circa 15 Jahren abzubilden. Die Verwendung spezieller Mikrofiltertiegel in Lysimeter-Experimenten ermöglicht die Abschätzung der Partikelgrößen des emittierten MP, was eine Grundbedingung für die Bewertung einer potenziellen Gesundheitsgefährdung für Menschen ist. Ergänzend wurden weitere umweltrelevante Schadstoffausträge aus den Kunststoffrasen quantifiziert.
KW - Mikroplastik
KW - Kunststoffrasen
KW - Schadstoffe
KW - Bewitterung
KW - Lysimeter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633114
DO - https://doi.org/10.26272/opus4-63311
N1 - Das Projekt wurde gefördert vom Bundesinstitut für Bau-, Stadt- und Raumforschung (BBSR) im Auftrag des Bundesministeriums für Wohnen, Stadtentwicklung und Bauwesen (BMWSB) aus Mitteln des Innovationsprogramms Zukunft Bau. Aktenzeichen: FKZ 10.08.18.7-22.02. Projektlaufzeit: 09.2022 bis 03.2025.
SP - 1
EP - 75
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-63311
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dorau, Kristof
A1 - Rückamp, Daniel
A1 - Weber, Christian
A1 - Scheeder, Georg
A1 - Reßing, Ronja
A1 - Peth, Stephan
A1 - Otto, Philipp
A1 - Altmann, Korinna
A1 - Fries, Elke
A1 - Hoppe, Martin
T1 - Characterization and spatial distribution of mesoplastics in an arable soil
N2 - AbstractExtraction of plastic particles from soil is challenging and, thus, exceptionally little spatial information on plastic distribution at the field scale has been gathered. However, for environmental risk assessment, adequate sampling should complement coherent plastic profiling. In this study, we investigated the spatial distribution of mesoplastics (MePs; from 5 mm up to 130 mm) in arable soil (Haplic Cambisol) managed intensively by 12 years of compost application. Geo‐referenced samples (n = 128) and five different sampling designs (n = 45) of variable sampling volume (from 2 to 300 L) were collected at a three hectare study site in Northern Germany (0–30 cm soil depth). Soil properties such as pH and soil organic carbon (SOC) were measured to evaluate dispersion measures of these data. In total, we found 259 MePs with a predominance of transparent packaging foils made of polyethylene and coloured fibres of polypropylene. Average particle metrics were a projection area of 47 (3–400) mm2, a Feret diameter of 18.5 (5.4–130) mm and a mass of 1.89 (0.11–221) mg. Caution is advised when measuring the particle mass due to still strongly adhering soil material, especially for fibre bundles with 0.544 mg soil mg−1 particle. We recommend using a 0.1 mol L−1 tetrasodium pyrophosphate solution to purify MePs by removing attached soil before weighing for further environmental risk assessment. The MePs count with a median value of 0.50 (0–3.2) particles kg−1 and median mass of 2.26 (0–221) mg kg−1 featured the highest coefficient of variation (CV) with 103% and 187%, respectively. This is 10–20 times larger in comparison to the CV of SOC (9.2%) and even 50–93 times larger than CV of soil pH (2.2%). This leads to the need of larger sample numbers to delineate plastic metrics in comparison with soil properties to identify a reliable mean value of the field within a predefined allowable error. Mesoplastics in the soil were characterized by a pure nugget effect variogram (no spatial correlation), revealed no intrafield variability and the sample volume yielded inconclusive results. Sampling for plastics in soil should either (i) drastically increase the sample number for a single field or (ii) communicate transparently that the allowable error is by far enhanced in comparison with classical soil properties like pH and SOC. More systematic studies featuring geo‐spatial analysis of MePs and smaller‐sized plastics in soils are required to propose adequate sampling designs across multiple land uses and plastics fingerprints. A larger database would, thereupon, pave the way for best‐practice guides on how to treat ‘outliers’ and search for robust estimators for spatial mapping of plastics in soils.
KW - Large microplastics
KW - Microplastics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617772
DO - https://doi.org/10.1111/ejss.70016
VL - 75
IS - 6
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-61777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wimmer, L
A1 - Hoang, M V N
A1 - Schwarzinger, J
A1 - Jovanovic, V
A1 - Adelkovic, B
A1 - Velickovic, T C
A1 - Meisel, T C
A1 - Waniek, T
A1 - Weimann, Christiane
A1 - Altmann, Korinna
A1 - Dailey, L A
T1 - A quality-by-design inspired approach to develop PET and PP nanoplastic test materials for use in in vitro and in vivo biological assays
N2 - Micro- and nanoplastics have become environmental pollutants of concern, receiving increased attention from consumers, scientists, and policymakers. The lack of knowledge about possible impacts on wildlife and human health requires further research, for which well-characterized testmaterials are needed. A quality-bydesign (QbD) driven approachwas used to produce sterile, endotoxinmonitored nanoplastics of polyethylene terephthalate (PET) and polypropylene (PP) with a size fraction of >90% below 1 μm and high yield of >90%. Glycerol was used as a versatile and biocompatible liquid storage medium which requires no further exogenous dispersing agent andmaintained colloidal stability, sterility (0 CFU mL−1), and low endotoxin levels (<0.1 EU mL−1) for more than one year of storage at room temperature. Further, the glycerol vehicle showed no biological effect on the tested human bronchial cell line Calu-3 up to 0.8% (w/v). Given the concentration of 40 mg g−1 nanoplastics in the glycerol stock, this corresponds to a nanoplastic concentration of 320 μg mL−1. The surfactant-free nanoplastics are dispersible in bio-relevant media from the glycerol stock without changing size characteristics and are suitable for in vitro and in vivo research.
KW - Microplastics
KW - Reference materials
KW - Nanoplastics
KW - Polymer 3R
KW - Glycerol
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629934
DO - https://doi.org/10.1039/D4EN01186D
SN - 2051-8161
VL - 12
IS - 5
SP - 2667
EP - 2686
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-62993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Prinz, Carsten
A1 - Prieto-Laria, P.
A1 - Ruiz-Salvador, A.R.
A1 - Ballesteros, M.
T1 - Engineering a multivariate cobalt metal–organic framework for high photocatalytic activity: the impact of mixed ligands and metal incorporation in a visible light-driven heterogeneous photo-Fenton reaction for water treatment
N2 - Metal–organic frameworks (MOFs) have attracted increasing attention for the removal of organic pollutants in wastewater via photocatalysis. Here, we design a multivariate modification of ZIF-9 to tune its electronic properties for use in visible light photocatalysis. A controllable synthesis of ZIF-9 and its multivariate forms with the incorporation of copper and the 2-imidazolecarboxaldehyde (ica) ligand was carried out. The materials are tested for the removal of the model dye methylene blue (MB) by a heterogeneous photo-Fenton-like reaction at neutral pH and room temperature. Cu-ZIF-9-ica (UPO-3) shows high photocatalytic activity under both visible and ultraviolet A (UVA) light, achieving 94% MB degradation in 45 min, compared to 65% MB degradation in 120 min using bare ZIF-9. The study revealed a first-order rate constant of 0.0475 min−1 for Cu-ZIF-9-ica compared to 0.0088 min−1 for ZIF-9 under visible light. The improvement of the catalyst was clearly attributed to the co-incorporation of Cu and the ica ligand in the MOF, which reduces the band gap, in agreement with DFT calculations. Reproducibility and recyclability tests proved that Cu-ZIF-9-ica can be used for at least 3 cycles without a significant loss of efficiency, making it a promising material for the study and application of wastewater treatment.
KW - Metal-Organic Framework (MOF)
KW - Heterogeneous photo-Fenton
KW - ZIF-9
KW - Methylene Blue
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630797
DO - https://doi.org/10.1039/d4na00954a
SN - 2516-0230
VL - 7
IS - 8
SP - 2255
EP - 2265
PB - Royal Society of Chemistry
AN - OPUS4-63079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Visileanu, Emilia
A1 - Catalin Grosu, Marian
A1 - Tiberiu Miclea, Paul
A1 - Altmann, Korinna
A1 - Brossell, Dirk
T1 - Methods for the collection and characterization of airborne particles in the textile industry
N2 - Airborne particulate matter is one of the main air pollutants. Their impact on mortality, and the occurrence of pulmonary and cardiovascular complications, have been the subject of numerous studies. Airborne particles are complex mixtures of organic and inorganic substances from different sources of particle emissions. Particulate Matter (PM) particles are classified according to their aerodynamic diameter expressed in µm and can vary from coarse (PM 10) to fine (less than PM 2.5). These diameter considerations are fundamental because they condition the penetration of particles into the bronchopulmonary system and the body. In recent years, there has been an interest in so-called “ultra-fine” particles, with a diameter of 0.1 µm (or 100 nm), or PM 0.1. They are nanoparticles and their impact on human health is not yet clear.With more than 1.5 million employees, textiles and clothing is a diverse sector that plays an important role in the European manufacturing industry, producing a turnover of €162 billion.An important component of the solid particles that generate air pollution in the textile industry is microplastics (MP) and nano plastics (NP), which also include microfibers (<5mm) and nanofibers (<100 nm), respectively. The particles released into the air during fiber and yarn processing range from 1 µg/m3 to 50 µg/m3.The paper presents the results of the determination of indoor and outdoor air concentration levels in textile companies, to identify the areas with the highest concentration level, by using an online recording system such as the Laser Aerosol Spectrometer MINI LAS model 11-E. The total concentration level TSP (µg/m3), the fractions PM 10(µg/m3), PM 2.5(µg/m3), PM1(µg/m3), as well as the total number of particles TC (1/l), were shown. It was noted that TSP is approximately at the same level both indoors and outdoors, but the fractions of PM10, PM2.5, and PM1 have much higher values indoors than outdoors with possible consequences on workers' health.The next step was the collection of fibers, namely micro and nano plastic particles from the vicinity of the workplaces of polyester, polyamide, and polypropylene fibers processing units in the textile industry in Romania, to obtain a sufficient quantity for laboratory analysis to determine the size and shape of the particles as well as their chemical composition. Two types of pumps were used, differentiated by their operating parameters: TECORA SKYPOST with airflow of 38 l/min and GILAIRPLUS with airflow 2l/min. Filters made of different materials with different diameters and pore sizes were used, namely: quartz filters (ø 47 mm, and ø 37 mm) on a TECORA SKYPOST type pump, polycarbonate nucleopore coated with a gold membrane (ø 25 mm) and silica filter (ø 9 mm) on GILAIRPLUS type pump.Using descriptive statistics, the calculation of correlation coefficients highlighted a strong correlation between the variables: "Collected mass/ Air concentration" and "Collected mass/ Air volume" for all diameters of the filters.The highest collected particle volume, determined by weighing the filters before and after collection, was obtained with the quartz filters (ø 47 mm) at an airflow of 38 l/min. The particles collected (polyester, polyamide, polypropylene) in the first stage were analyzed by SEM and thermogravimetric and it was found that the quartz filters absorbed the particles inside, with very few remaining on the surface. Thus no known methods can be used to perform analysis for particles collected on quartz filters. The number of particles on the filters was insufficient for analysis either because of the collection parameters used or because of the loss of particles during transport. As a result, in the next step, the use of 9 mm Si filters using the GILAIRPLUS pump at an airflow rate of 2l/min was chosen.To improve the transport conditions and avoid the loss of the particles and keep them on the surface of the filters, two methods were applied:- after weighing the filters were reintroduced into the collection pump holder;- a filtration system for airborne micro-nano plastics was designed and manufactured to selectively collect and transport PM10 and PM1 particles collected on SI filters.In both cases, SEM, Raman mapping, and GS-MS microscopy were used for analysis.Several times more PM10 than PM1 (74.5µg compared to 12.5 µg) was found. In all cases, both particles and fibers showed the same Raman fingerprint.The GS-MS analyses showed some contamination of the workspaces with particles other than the processed fibers. The presence of non-notifiable substances was also observed.The most viable filters are Si filters with a pore size of 10 microns to 1 micron and the use of the selected collection and transport filter system. In the following a filter system will be applied for collection on Au membrane-coated polycarbonate filters.
T2 - 5th International Conference on Human Systems Engineering and Design: Future Trends and Applications (IHSED 2023)
KW - Microplastics
KW - Textiles
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624442
DO - https://doi.org/10.54941/ahfe1004132
VL - 112
SP - 212
EP - 223
PB - AHFE International
AN - OPUS4-62444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Identification of toxicologically relevant functional groups on micro- and nanoplastic particles’ surface by means of X-Ray photoelectron spectroscopy
N2 - Microplastic and nanoplastic particles (MNP) are spread all over the world in various types, shapes and sizes making it very challenging to accurately analyse them. Each sampling procedure, sample preparation method and detection technique needs suitable reference materials to validate the method for accurate results. Furthermore, the effects of these MNPs should be evaluated by risk and hazard assessment with test particles close to reality. To better understand MNP behavior and aid in clarification of their interactions with organisms, we produced several MNP materials by top-down procedure and characterized their properties. Since surface properties mostly determine particles’ toxicity, the aim of the present study was to determine which functional groups are present on MNPs and how the surface can be affected by the production process and particle’s environment.
T2 - SETAC 34th Meeting
CY - Seville, Spain
DA - 05.05.2024
KW - Microplastics
KW - Nanoplastics
KW - Polypropylene
KW - XPS
KW - SEM
PY - 2024
AN - OPUS4-60037
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Realitätsnahe Referenzmaterialien für die Mikroplastik-Analytik und Vergleichsuntersuchungen
N2 - Zur Validierung und Harmonisierung von verschiedenen Methoden in der Mikroplastik-Analytik werden polymere Referenzmaterialien benötigt. In diesem Vortrag wird dargestellt, was bisher an der BAM zu Referenzmaterialien für die Mikroplastik-Analytik entwickelt wurde, wo es hingehen soll und ein Überblick über bisher gelaufene Vergleichsuntersuchungen gebracht.
T2 - Kick-off Meeting "Mikroplastik in Lebensmitteln"
CY - Online meeting
DA - 03.12.2020
KW - Mikroplastik
KW - Referenzmaterial
KW - Vergleichsuntersuchungen
KW - Ringversuche
PY - 2020
AN - OPUS4-51743
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tscheuschner, Georg
A1 - Ponader, Marco
A1 - Raab, Christopher
A1 - Weider, Prisca S.
A1 - Hartfiel, Reni
A1 - Kaufmann, Jan Ole
A1 - Völzke, Jule L.
A1 - Bosc-Bierne, Gaby
A1 - Prinz, Carsten
A1 - Schwaar, T.
A1 - Andrle, Paul
A1 - Bäßler, Henriette
A1 - Nguyen, Khoa
A1 - Zhu, Y.
A1 - Mey, A. S. J. S.
A1 - Mostafa, A.
A1 - Bald, I.
A1 - Weller, Michael G.
T1 - Efficient Purification of Cowpea Chlorotic Mottle Virus by a Novel Peptide Aptamer
N2 - The cowpea chlorotic mottle virus (CCMV) is a plant virus explored as a nanotechnological platform. The robust self-assembly mechanism of its capsid protein allows for drug encapsulation and targeted delivery. Additionally, the capsid nanoparticle can be used as a programmable platform to display different molecular moieties. In view of future applications, efficient production and purification of plant viruses are key steps. In established protocols, the need for ultracentrifugation is a significant limitation due to cost, difficult scalability, and safety issues. In addition, the purity of the final virus isolate often remains unclear. Here, an advanced protocol for the purification of the CCMV from infected plant tissue was developed, focusing on efficiency, economy, and final purity. The protocol involves precipitation with PEG 8000, followed by affinity extraction using a novel peptide aptamer. The efficiency of the protocol was validated using size exclusion chromatography, MALDI-TOF mass spectrometry, reversed-phase HPLC, and sandwich immunoassay. Furthermore, it was demonstrated that the final eluate of the affinity column is of exceptional purity (98.4%) determined by HPLC and detection at 220 nm. The scale-up of our proposed method seems to be straightforward, which opens the way to the large-scale production of such nanomaterials. This highly improved protocol may facilitate the use and implementation of plant viruses as nanotechnological platforms for in vitro and in vivo applications.
N2 - Das Cowpea Chlorotic Mottle Virus (CCMV) ist ein Pflanzenvirus, das als nanotechnologische Plattform erforscht wird. Der robuste Selbstorganisationsmechanismus seines Kapsidproteins ermöglicht die Verkapselung und gezielte Abgabe von Medikamenten. Darüber hinaus kann das Kapsid-Nanopartikel als programmierbare Plattform für die Präsentation verschiedener molekularer Komponenten verwendet werden. Im Hinblick auf künftige Anwendungen ist eine effiziente Produktion und Reinigung von Pflanzenviren von entscheidender Bedeutung. In etablierten Protokollen stellt die notwendige Ultrazentrifugation aufgrund von Kosten, schwieriger Skalierbarkeit und Sicherheitsaspekten eine erhebliche Einschränkung dar. Darüber hinaus bleibt die Reinheit des endgültigen Virusisolats oft unklar. Hier wurde ein fortschrittliches Protokoll für die Reinigung von CCMV aus infiziertem Pflanzengewebe entwickelt, wobei der Schwerpunkt auf Effizienz, Wirtschaftlichkeit und Reinheit lag. Das Protokoll beinhaltet eine Fällung mit Polyethylenglycol (PEG 8000), gefolgt von einer Affinitätsextraktion mit einem neuartigen Peptid-Aptamer. Die Effizienz des Protokolls wurde mithilfe von Größenausschluss-Chromatographie (SEC), MALDI-TOF-Massenspektrometrie, Umkehrphasen-HPLC und Sandwich-Immunoassay validiert. Darüber hinaus wurde nachgewiesen, dass das endgültige Eluat der Affinitätssäule eine außergewöhnliche Reinheit (98,4 %) aufweist, die durch HPLC und Detektion bei 220 nm bestimmt wurde. Die Skalierung der von uns vorgeschlagenen Methode scheint einfach zu sein, was den Weg für eine größer angelegte Produktion solcher Nanomaterialien ebnet. Dieses stark verbesserte Protokoll könnte die Verwendung und Umsetzung von Pflanzenviren als nanotechnologische Plattformen für In-vitro- und In-vivo-Anwendungen erleichtern.
KW - Affinity chromatography
KW - Nanoparticles
KW - Nanoscience
KW - Carrier protein
KW - Encapsulation
KW - Combinatorial peptide library
KW - Peptide binder
KW - Vigna unguiculata
KW - Augenbohne
KW - Schlangenbohne
KW - Pflanzenvirus
KW - Plant virus
KW - Upscaling
KW - Commercialization
KW - Reference material
KW - Nanocarrier
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572645
DO - https://doi.org/10.3390/v15030697
VL - 15
IS - 3
SP - 1
EP - 24
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-57264
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beslic, D.
A1 - Tscheuschner, Georg
A1 - Renard, B. Y.
A1 - Weller, Michael G.
A1 - Muth, Thilo
T1 - Comprehensive evaluation of peptide de novo sequencing tools for monoclonal antibody assembly
N2 - Monoclonal antibodies are biotechnologically produced proteins with various applications in research, therapeutics and diagnostics. Their ability to recognize and bind to specific molecule structures makes them essential research tools and therapeutic agents. Sequence information of antibodies is helpful for understanding antibody–antigen interactions and ensuring their affinity and specificity. De novo protein sequencing based on mass spectrometry is a valuable method to obtain the amino acid sequence of peptides and proteins without a priori knowledge. In this study, we evaluated six recently developed de novo peptide sequencing algorithms (Novor, pNovo 3, DeepNovo, SMSNet, PointNovo and Casanovo), which were not specifically designed for antibody data. We validated their ability to identify and assemble antibody sequences on three multi-enzymatic data sets. The deep learning-based tools Casanovo and PointNovo showed an increased peptide recall across different enzymes and data sets compared with spectrum-graph-based approaches. We evaluated different error types of de novo peptide sequencing tools and their performance for different numbers of missing cleavage sites, noisy spectra and peptides of various lengths. We achieved a sequence coverage of 97.69–99.53% on the light chains of three different antibody data sets using the de Bruijn assembler ALPS and the predictions from Casanovo. However, low sequence coverage and accuracy on the heavy chains demonstrate that complete de novo protein sequencing remains a challenging issue in proteomics that requires improved de novo error correction, alternative digestion strategies and hybrid approaches such as homology search to achieve high accuracy on long protein sequences.
KW - De novo peptide sequencing
KW - Bioinformatics
KW - Benchmarking study
KW - Monoclonal antibody
KW - Mass spectrometry
KW - Sequence coverage
KW - Light chains
KW - Heavy chains
KW - IgG
KW - Immunoglobulins
KW - Error correction
KW - Sequencing algorithm
KW - Preprocessing
KW - Missing fragmentation sites
KW - Deep learning-based tools
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570363
DO - https://doi.org/10.1093/bib/bbac542
VL - 24
IS - 1
SP - 1
EP - 12
PB - Oxford University Press
AN - OPUS4-57036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yanchen
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Montoro, Luciano A.
A1 - Liu, Hao
A1 - Liu, Ye
A1 - Emmerling, Franziska
A1 - Russo, Patrícia A.
A1 - Pinna, Nicola
T1 - A partially disordered crystallographic shear block structure as fast-charging negative electrode material for lithium-ion batteries
N2 - A well-ordered crystalline structure is crucial in battery electrodes, as the dimensionality and connectivity of the interstitial sites inherently influence Li+ ions diffusion kinetics. Niobium tungsten oxides block structures, composed of ReO3-type blocks of specific sizes with well-defined metal sites, are promising fast-charging negative electrode materials. Structural disorder is generally detrimental to conductivity or ion transport. However, here, we report an anomalous partially disordered Nb12WO33 structure that significantly enhances Li-ion storage performance compared to the known monoclinic Nb12WO33 phase. The partially disordered phase consists of corner-shared NbO6 octahedra blocks of varied sizes, including 5×4, 4×4, and 4×3, with a disordered arrangement of distorted WO4 tetrahedra at the corners of the blocks. This structural arrangement is robust during lithiation/delithiation, exhibiting minor local structure changes during cycling. It enables accelerated Li-ion migration, resulting in promising fast-charging performance, namely, 62.5 % and 44.7 % capacity retention at 20 C and 80 C, respectively. This study highlights the benefits of introducing disorder into niobium tungsten oxide shear structures, through the establishment of clear structure-performance correlations, offering guidelines for designing materials with targeted properties.
KW - Lithium ion batteries
KW - Oxides
KW - XANES
KW - XRD
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637994
DO - https://doi.org/10.1038/s41467-025-61646-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-63799
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Roy, Arkendu
A1 - Karafiludis, Stephanos
A1 - Kumar, Sourabh
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Stawski, Tomasz M.
A1 - Miliūtė, Aistė
A1 - von der Au, Marcus
A1 - Ahrens, Mike
A1 - Braun, Thomas
A1 - Emmerling, Franziska
T1 - Zirconium fluoride-supported high-entropy fluoride: a catalyst for enhanced oxygen evolution reaction
N2 - Extended hydrogen initiatives promote the urgency of research on water splitting technologies and, therein, oxygen evolution reaction catalysts being developed. A route to access a ZrF4 supported high-entropy fluoride catalyst using a facile sol–gel route is presented. The high-entropy character of the catalyst was confirmed by scanning transmission electron microscopy and energy dispersive X-ray spectroscopy (STEM-EDX) as well as inductively coupled plasma-mass spectrometry (ICP-MS). Additional investigations on the local structure were performed using extended X-ray absorption fine structure spectroscopy (EXAFS) and pair distribution function (PDF) analysis. The catalyst shows significant potential for oxygen evolution reaction (OER) in alkaline media with a current density of 100 mA cm−2 at approximately 1.60 V, thus outperforming benchmark materials such as IrO2, despite a significant reduction in electrochemical mass loading. A potential mechanism is suggested based on free energy calculation using DFT calculations.
KW - OER
KW - HEA
KW - CCMAT
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637116
DO - https://doi.org/10.1039/D4TA08664C
SN - 2050-7488
VL - 13
IS - 26
SP - 20383
EP - 20393
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmar, Stefan
A1 - Weyrauch, Steffen
A1 - Reemtsma, Thorsten
A1 - Eisentraut, Paul
A1 - Altmann, Korinna
A1 - Ruhl, Aki S.
A1 - Jekel, Martin
T1 - Settling Velocities of Tire and Road Wear Particles: Analyzing Finely Graded Density Fractions of Samples from a Road Simulator and a Highway Tunnel
N2 - The terminal settling velocity is considered the most critical parameter determining the transport of tire and road wear particles (TRWP) in aquatic environments. Nonetheless, no respective empirical data has been reported so far. In this study, particle samples from a road simulator and a highway tunnel were investigated with a validated imaging method. Different density and size fractions of both samples were measured separately, acquiring sizes and settling velocities of more than 30,000 individual particles. In addition, tire marker polymers were analyzed for each fraction via thermal extraction desorption-gas chromatography/mass spectrometry. Finally, the acquired particle data was combined according to the fractions’ estimated tire contents in order to deduce detailed probability distributions of particle size and settling velocity for the actual TRWP from both samples. Weighted by TRWP-incorporated tire mass, median diameters of 54 and 44 μm as well as median settling velocities of 0.65 and 0.22 mm/s were found for TRWP from the road simulator and highway tunnel, respectively. This study thus provides the first ever empirical data on TRWP settling velocities in water, which can be highly valuable input for modeling the environmental transport of TRWP and for dimensioning TRWP retention systems.
KW - Microplastics
KW - TED-GC/MS
KW - Sinking velocities
KW - Transport
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635449
DO - https://doi.org/10.1021/acs.est.5c04165
SN - 0013-936X
VL - 59
IS - 26
SP - 13434
EP - 13446
PB - American Chemical Society (ACS)
AN - OPUS4-63544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Prasenjit
A1 - Chakraborty, Gouri
A1 - Yang, Jin
A1 - Roeser, Jérôme
A1 - Küçükkeçeci, Hüseyin
A1 - Nguyen, Anh Dung
A1 - Schwarze, Michael
A1 - Gabriel, Jose
A1 - Penschke, Christopher
A1 - Du, Shengjun
A1 - Weigelt, Vincent
A1 - Khalil, Islam E.
A1 - Schmidt, Johannes
A1 - Saalfrank, Peter
A1 - Oschatz, Martin
A1 - Rabeah, Jabor
A1 - Schomäcker, Reinhard
A1 - Emmerling, Franziska
A1 - Thomas, Arne
T1 - The Effect of Pore Functionality in Multicomponent Covalent Organic Frameworks on Stable Long‐Term Photocatalytic H2 Production
N2 - AbstractIn nature, organic molecules play a vital role in light harvesting and photosynthesis. However, regarding artificial water splitting, the research focus is primarily on inorganic semiconductors. Although organic photocatalysts have high structural variability, they tend to exhibit lower quantum efficiencies for water splitting than their inorganic counterparts. Multicomponent reactions (MCRs) offer an attractive route to introduce different functional units into covalent organic frameworks (COFs) and enable semiconducting properties and high chemical stability, creating promising materials for long‐term photocatalytic applications, such as H2 production. Herein, five highly crystalline donor‐acceptor based, 4‐substituted quinoline‐linked MCR‐COFs are presented that are prepared via the three‐component Povarov reaction. The pore functionality is varied by applying different vinyl derivatives (e.g., styrene, 2‐vinyl pyridine, 4‐vinylpyridine, 4‐vinyl imidazole, 2,3,4,5,6‐pentafluorostyrene), which has a strong influence on the obtained photocatalytic activity. Especially an imidazole‐functionalized COF displays promising photocatalytic performance due to its high surface area, crystallinity, and wettability. These properties enable it to maintain its photocatalytic activity even in a membrane support. Furthermore, such MCR‐COFs display dramatically enhanced (photo)chemical stability even after long‐term solar light irradiation and exhibit a high and steady H2 evolution for at least 15 days.
KW - Sstability
KW - Covalent organic frameworks
KW - Pore functionality
KW - Long-term H2 production
KW - Multicomponent reactions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639787
DO - https://doi.org/10.1002/aenm.202501193
SN - 1614-6832
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-63978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Domínguez-Santos, J. Enrique
A1 - Bhattacharya, Biswajit
A1 - Prinz, Carsten
A1 - Canosa, Inés
A1 - Flores, Amando
A1 - Jiménez-Rodríguez, Antonia
A1 - Ruiz-Salvador, A. Rabdel
A1 - Emmerling, Franziska
A1 - Ballesteros, Menta
T1 - Mechanochemical synthesis of multivariate UPO-3 (Cu-ZIF-9-ica) MOF for inactivation of antibiotic-resistant bacteria and irrigation-quality water production via heterogeneous photo-Fenton catalysis
N2 - Water scarcity and pollution are critical global challenges, particularly in agriculture, the largest consumer of water. The development of sustainable, effective, and environmentally friendly disinfection methods is essential to address the risks posed by antibiotic-resistant bacteria and to ensure safe reuse of water for irrigation. In this study, we report the synthesis of the metal-organic framework (MOF) Universidad Pablo de Olavide-3 (UPO-3) via a mechanochemical approach, a scalable and sustainable method compared to traditional solvothermal synthesis. The resulting UPO-3/H2O2 system exhibits robust photocatalytic properties under visible light, achieving effective and broad-spectrum antibacterial activity. The disinfection efficiency of the catalyst was evaluated against Escherichia coli as a model of microbial pathogen in two saline matrices, considering the key parameters of the heterogeneous photo-Fenton process, including catalyst dosage, initial H2O2 concentration, and light irradiation. Notably, it inactivated two important virulent and antibiotic-resistant bacterial pathogens (Staphylococcus aureus and Pseudomonas aeruginosa). Furthermore, UPO-3 shows exceptional performance under real-world conditions, such as river water disinfection, achieving >5-log reduction of E. coli, fulfilling a critical criterion for Class A water reuse under Regulation (EU) 2020/741. These results highlight UPO-3 as a versatile and sustainable solution for water reuse, addressing water scarcity and advancing efforts to achieve United Nations Sustainable Development Goal 6.
KW - Water reuse
KW - Antibiotic-resistant bacteria
KW - Water disinfection
KW - Mechanochemical synthesis
KW - Metal organic framework
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639766
DO - https://doi.org/10.1016/j.chemosphere.2025.144610
SN - 0045-6535
VL - 386
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Go, Eun Sul
A1 - Hong, Eun Ji
A1 - Lee, Ji Yeong
A1 - Stolar, Tomislav
A1 - Peterson, Gregory I.
A1 - Emmerling, Franziska
A1 - Kim, Kyoungsoo
A1 - Kim, Jeung Gon
T1 - Insights into Mechanochemical Solid-State Ball-Milling Reaction: Monitoring Transition from Heterogeneous to Homogeneous Conditions
N2 - As mechanochemical synthesis has advanced significantly, there has been intense interest in understanding the underlying mechanisms of these reactions. Given that many mechanochemical processes are conducted in the solid-state without solvation yet sometimes yield faster reactions than those in solution, we sought to address the following question: Are mechanochemical reactions homo- or heterogeneous? To investigate, we employed a model system involving the mixing and copolymerization of l-lactide (LLA) and d-lactide (DLA), monitored through powder X-ray diffraction (PXRD), nuclear magnetic resonance, and differential scanning calorimetry. In situ and ex situ PXRD analyses of the mixture of LLA and DLA showed that vibratory ball milling rapidly transformed the initially heterogeneous lactide mixture into a homogeneous phase within one min due to collisions between the balls and the jar. By varying the milling conditions, we were able to regulate the level of mixing, which subsequently influenced the copolymerization outcomes. In the solid-state ball-milling copolymerization of LLA and DLA in the presence of a catalyst and initiator, multiblock copolymers of poly(l-lactic acid) and poly(d-lactic acid) were formed within one min during the early stage of the reaction, when incomplete mixing of the monomers led to a process governed by phase heterogeneity. In contrast, prolonged polymerization promoted conditions approaching homogeneity, ultimately yielding atactic poly(lactic acid). This transition from heterogeneous to homogeneous reactions is a distinctive feature compared to conventional homogeneous reactions, potentially leading to mechano-exclusive reaction designs.
KW - Mechanochemistry
KW - Ball-milling
KW - Homogeneous reaction
KW - Heterogeneous reaction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638008
DO - https://doi.org/10.1021/jacsau.5c00322
SN - 2691-3704
VL - 5
IS - 6
SP - 2720
EP - 2727
PB - American Chemical Society (ACS)
AN - OPUS4-63800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Sustainable mechanochemical approach for the selective synthesis of multicomponent organic solids: real-time in situ insights
N2 - Crystalline multicomponent organic solids (MOSs) such as cocrystals and ionic cocrystals hold immense potential in diverse functional applications, ranging from pharmaceuticals to optoelectronics. However, conventional solution-based crystallization methods often result in polymorphic mixtures and lack precise control over product composition. Herein, we report a comparative investigation of solution crystallization versus mechanochemical synthesis for constructing MOSs from 9-anthracenecarboxylic acid (ACA) and 4,4 '-bipyridine (BPY). Solution-based approaches consistently yielded concomitant formation of neutral cocrystal (CC) and ionic cocrystal (ICC) forms, regardless of the solvent used. The resulting multicomponent solids were comprehensively characterized using a combination of single crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and thermogravimetric analysis. In contrast, mechanochemical methods, including neat grinding (without solvent) and liquid-assisted grinding (with minimum solvent), enabled selective formation of either a phase pure CC or ICC form. Less polar and nonpolar organic solvents favor the kinetic CC, while polar water promotes formation of the thermodynamically stable ICC. Time-resolved in situ powder X-ray diffraction (TRIS-PXRD) captures the dynamic evolution of solid-state phases and reveals the complete transformation of the CC into ICC under neat grinding or water-assisted conditions. This study highlights the powerful role of mechanochemistry and in situ monitoring in steering solid-state reactivity and offers a sustainable pathway for the targeted and scalable synthesis of pure multicomponent organic materials.
KW - Cocrystal
KW - Synchrotron X-ray powder diffraction
KW - Time-resolved in situ investigation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641409
DO - https://doi.org/10.1039/D5CE00663E
SN - 1466-8033
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64140
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Gabler, Mariella
T1 - Development of an affinity-based method for the site-selective synthesis of antibody-drug-conjugates
N2 - For the site-selective synthesis of ADCs, a variety of obstacles must be overcome. Those include designing bifunctional affinity peptides with reasonably low 𝐾𝑑-values that couple to the mAb in a site-selective manner. These peptides should also include a functional group that links the payload to the mAb under mild conditions without adversely affecting it. The bioconjugation between peptide and antibody and the linker between peptide and payload must be stable and durable to provide safety when used for medical purposes. The usage of metals and organic solvents should be minimized. Within the project, new types of functionalized affinity peptides were designed, and their affinity towards the Fc-fragment was determined.
KW - Antibody drug conjugate
KW - ADC
KW - Human antibody
KW - Peptide
KW - Linker
KW - Toxin
KW - Payload
KW - Monomethyl Auristatin E
KW - MMAE
KW - DM1
KW - Click chemistry
KW - Copper-catalyzed
KW - SDS-PAGE
KW - HPLC
KW - Trastuzumab
KW - Herceptin
KW - SPR
KW - MALDI-TOF-MS
KW - Mertansine
KW - Site-selective bioconjugation
KW - Affinity
PY - 2021
SP - 1
EP - 100
PB - Humboldt-Universität zu Berlin
CY - Berlin
AN - OPUS4-54519
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Scoppola, E.
A1 - Wolf, S.E.
A1 - Kochovski, Z.
A1 - Matzdorff, D.
A1 - Van Driessche, A. E. S.
A1 - Hövelmann, J.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz M.
T1 - Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formation
N2 - The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH₄PO₄ · 6H₂O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization. In this study, we use synchrotron-based in situ x-ray scattering complemented by cryogenic transmission electron microscopy to obtain new insights from the earliest stages of struvite formation. The holistic scattering data captured the structure of an entire assembly in a time-resolved manner. The structural features comprise the aqueous medium, the growing struvite crystals, and any potential heterogeneities or complex entities. By analysing the scattering data, we found that the onset of crystallization causes a perturbation in the structure of the surrounding aqueous medium. This perturbation is characterized by the occurrence and evolution of Ornstein-Zernike fluctuations on a scale of about 1 nm, suggesting a non-classical nature of the system. We interpret this phenomenon as a liquid-liquid phase separation, which gives rise to the formation of the amorphous precursor phase preceding actual crystal growth of struvite. Our microscopy results confirm that the formation of Mg-struvite includes a short-lived amorphous phase, lasting >10 s.
KW - Physical and theoretical chemistry
KW - Non-classical crystallization
KW - Struvite
KW - Liquid-liquid-phase-separation
KW - Nucleation
KW - Crystallization
KW - In-situ scattering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584766
DO - https://doi.org/10.1063/5.0166278
SN - 1089-7690
VL - 159
IS - 13
SP - 1
EP - 12
PB - AIP Publishing
CY - Woodbury, NY
AN - OPUS4-58476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Edzards, Joshua
A1 - Saßnick, Holger-Dietrich
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Valencia, Ana M.
A1 - Emmerling, Franziska
A1 - Beyer, Sebastian
A1 - Cocchi, Caterina
T1 - Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks
N2 - Due to their favorable properties and high porosity, zeolitic imidazolate frameworks (ZIFs) have recently received much limelight for key technologies such as energy storage, optoelectronics, sensorics, and catalysis. Despite widespread interest in these materials, fundamental questions regarding the zinc coordination environment remain poorly understood. By focusing on zinc(II)2-methylimidazolate (ZIF-8) and its tetrahedrally coordinated analogues with Br-, Cl-, and H-substitution in the 2-ring position, we aim to clarify how variations in the local environment of Zn impact the charge distribution and the electronic properties of these materials. Our results from densityfunctional theory confirm the presence of a Zn coordinative bond with a large polarization that is quantitatively affected by different substituents on the organic ligand. Moreover, our findings suggest that the variations in the Zn coordination induced by the functionalization have a negligible effect on the electronic structure of the considered compounds. On the other hand, halogen terminations of the ligands lead to distinct electronic contributions in the vicinity of the frontier region which ultimately reduce the band gap size by a few hundred millielectron volts. Experimental results obtained from X-ray absorption spectroscopy (Zn K-edge) confirm the trends predicted by theory and, together with them, contribute to a better understanding of the structure−property relationships that are needed to tailor ZIFs for target applications.
KW - Surfaces
KW - Physical and Theoretical Chemistry
KW - General Energy
KW - Electronic
KW - Coatings and Films
KW - Optical and Magnetic Materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589117
DO - https://doi.org/10.1021/acs.jpcc.3c06054
SN - 1932-7447
VL - 127
IS - 43
SP - 21456
EP - 21464
PB - American Chemical Society (ACS)
AN - OPUS4-58911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zuffa, Caterina
A1 - Cappuccino, Chiara
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Maini, Lucia
T1 - Liquid reagents are not enough for liquid assisted grinding in the synthesis of [(AgBr)(n-pica)]n
N2 - This study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)]n and [(AgBr)2(n-pica)]n to be obtained, and we report the new structures of [(AgBr)2(3-pica)]n and [(AgBr)2(4-pica)]n which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)]n/[(AgBr)2(n-pica)]n by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)]n is kinetically favoured while [(AgBr)2(3-pica)]n is converted into [(AgBr)(3-pica)]n only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile.
KW - Mechanochemistry
KW - Complex
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594755
DO - https://doi.org/10.1039/d3cp04791a
SN - 1463-9076
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheurrell, Kerstin
A1 - B. Martins, Inês C.
A1 - Murray, Claire
A1 - Emmerling, Franziska
T1 - Exploring the role of solvent polarity in mechanochemical Knoevenagel condensation: in situ investigation and isolation of reaction intermediates
N2 - Mechanochemistry has proven to be a highly effective method for the synthesis of organic compounds. We studied the kinetics of the catalyst-free Knoevenagel reaction between 4-nitrobenzaldehyde and malononitrile, activated and driven by ball milling. The reaction was investigated in the absence of solvents (neat grinding) and in the presence of solvents with different polarities (liquid-assisted grinding). The reaction was monitored using time-resolved in situ Raman spectroscopy and powder X-ray diffraction (PXRD). Our results indicate a direct relationship between solvent polarity and reaction kinetics, with higher solvent polarity leading to faster product (2-(4-nitrobenzylidone)malononitrile) formation. For the first time, we were able to isolate and determine the structure of an intermediate 2-(hydroxy(4-nitrophenyl)methyl)malononitrile based on PXRD data.
KW - Physical and Theoretical Chemistry
KW - General Physics and Astronomy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588071
DO - https://doi.org/10.1039/D3CP02883F
SN - 1463-9076
VL - 25
IS - 35
SP - 23637
EP - 23644
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Kunkel, Benny
A1 - Cakir, Cafer Tufan
A1 - Kabelitz, Anke
A1 - Witte, Steffen
A1 - Bernstein, Thomas
A1 - Bartling, Stephan
A1 - Radtke, Martin
A1 - Emmerling, Franziska
A1 - Abdel-Mageed, Ali Mohamed
A1 - Wohlrab, Sebastian
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time-, space- and energy-resolved in situ characterization of catalysts by X-ray absorption spectroscopy
N2 - A novel setup for dispersive X-ray absorption spectroscopy (XAS) with simultaneous resolution of space, time and energy for in situ characterization of solid materials is demonstrated.
KW - Dispersive XAS
KW - Catalysis
KW - In situ
KW - Structure analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584924
DO - https://doi.org/10.1039/d3cc03277a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Kneiske, Sönke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ahrens, Mike
A1 - Braun, Thomas
A1 - Emmerling, Franziska
T1 - A fluorolytic sol-gel route to access an amorphous Zr fluoride catalyst: A useful tool for C-F bond activation
N2 - A route to a ZrF4 catalyst active in room temperature Friedel–Crafts and dehydrofluorination reactions was developed via a fluorolytic sol–gel route, which was followed by a postfluorination step using a stream of CHClF2. The behaviour of different Zr(IV) precursors in a sol–gel reaction with anhydrous isopropanol/HF solution was investigated. The subsequent post-fluorination step was optimised in its temperature ramp and confirmed the necessity of a fluorination of the generated xerogels to obtain catalytic activity. The process is discussed in the context of the analysis of the materials using Brunauer–Emmett–Teller analysis (BET), powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The local structure of the amorphous catalyst was elucidated by extended X-ray absorption fine structure spectroscopy (EXAFS).
KW - Catalysis
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - Postfluorination
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593433
DO - https://doi.org/10.1039/D3CY01439H
SN - 2044-4761
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costa, Elena
A1 - Climent Terol, Estela
A1 - Gawlitza, Kornelia
A1 - Wan, Wei
A1 - Weller, Michael G.
A1 - Rurack, Knut
T1 - Optimization of analytical assay performance of antibody-gated indicator-releasing mesoporous silica particles
N2 - Antibody-gated indicator delivery (gAID) systems based on mesoporous silica nano- and microparticle scaffolds are a promising class of materials for the sensitive chemical detection of small-molecule analytes in simple test formats such as lateral flow assays (LFAs) or microfluidic chips. Their architecture is reminiscent of drug delivery systems, only that reporter molecules instead of drugs are stored in the voids of a porous host particle. In addition, the pores are closed with macromolecular “caps” through a tailored “gatekeeping” recognition chemistry so that the caps are opened when an analyte has reacted with a “gatekeeper”. The subsequent uncapping leads to a release of a large number of indicator molecules, endowing the system with signal amplification features. Particular benefits of such systems are their modularity and adaptability. With the example of the immunochemical detection of type-I pyrethroids by fluorescent dye-releasing gAID systems, the influence of several tuning modes on the optimisation of such hybrid sensory materials is introduced here. In particular, different mesoporous silica supports (from nano- and microparticles to platelets and short fibres), different functionalisation routes and different loading sequences were assessed. The materials’ performances were evaluated by studying their temporal response behaviour and detection sensitivity, including the tightness of pore closure (through the amount of blank release in the absence of analyte) and the release kinetics. Our results indicate that the better the paratope-accommodating Fab region of the antibody “cap” fits into the host material's pore opening, the better the closing/opening mechanism can be controlled. Because such materials are well-suited for LFAs, performance assessment included a test-strip format besides conventional assays in suspension. In combination with dyes as indicators and smartphones for read-out, simple analytical tests for use by untrained personnel directly at a point-of-need such as an aeroplane cabin can be devised, allowing for sensitivities down to the μg kg−1 range in <5 min with case-required selectivities.
KW - Antibody-gated indicator delivery
KW - Lateral flow assay
KW - SBA-15
KW - SBA-16
KW - Type-I pyrethroids
KW - Phenothrin
KW - Permethrin
KW - Etofenprox
KW - Amplification
KW - Biosensors
KW - Immunoassays
KW - Mesoporous particles
KW - Optical detection
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517053
DO - https://doi.org/10.1039/d0tb00371a
VL - 8
IS - 22
SP - 4950
EP - 4961
PB - Royal Society of Chemistry
AN - OPUS4-51705
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Sagar
A1 - Dolai, Malay
A1 - Nanda Goswami, Juli
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Drew, Michael G. B.
A1 - Chattopadhyay, Shouvik
A1 - Sarkar, Rabi Sankar
A1 - Sunil, Appu
A1 - Novitchi, Ghenadie
A1 - Moreno-Pineda, Eufemio
A1 - Wernsdorfer, Wolfgang
T1 - From strong to weak interaction: Reconciling SQUID and μSQUID-EPR data in anomalous Co(ii) dimers
N2 - Magnetic molecules have been proposed as scaffolds for novel quantum technologies, ranging from quantum sensing and quantum memory to multilevel quantum bits (qudits) and fault-tolerant quantum computation. Integration of magnetic molecules into cutting-edge applications hinges on a deep understanding and tunability of their spin states. To date, the strategic manipulation of the local environment of the ion and careful selection of the magnetic core have enabled the desired tunability and scalability of the spin states. For such goals, however, extracting the anisotropic parameters that dictate the characteristics of the Spin Hamiltonian is challenging, especially for molecules consisting of multiple magnetic cores. We address these challenges by studying two cobalt(II) dinuclear systems, complicated by inherent spin–orbit coupling. We explore the magnetic properties of these systems in two temperature regimes: (i) at sub-Kelvin temperatures employing single crystals at 30 mK using a unique μSQUID-EPR technique that examines the microwave absorption peaks in the magnetisation data and their variation with field angle and frequency; and (ii) in bulk employing convectional SQUID magnetometry above 2 K i.e., χMT(T) and M(H). Unexpectedly, sub-Kelvin temperature investigations reveal a negligible interaction, whereas the SQUID data reveal a much stronger interaction between the Co(II) ions. An understanding of these data is developed based on a strong coupling model and the coupling of two moieties with a spin-effective ground state.
KW - cOBALT(II)-complex
KW - In situ complex formation
KW - Magnetic property
KW - Crystal structure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641421
DO - https://doi.org/10.1039/D5QI01387A
SN - 2052-1553
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishra, Rajesh K.
A1 - Minussi, F.B.
A1 - Kumari, Priyanka
A1 - Shahi, Rohit R.
A1 - Yadav, R.P.
A1 - Emmerling, Franziska
A1 - Araújo, E.B.
T1 - Effect of sintering temperature on structural, microstructural, and dielectric properties of (Co0.2Fe0.2Ni0.2Al0.2Ti0.2)3O4 multi-cations high entropy oxides
N2 - The study reports the effect of sintering temperature on structural, microstructural, and dielectric properties of (Co0.2Fe0.2Ni0.2Al0.2Ti0.2)3O4 spinel high-entropy oxides (HEOs) synthesized through the solid-state mechanochemistry method. The sintering of the ceramic powders was accomplished at three different temperatures (1000 ◦C, 1100 ◦C, and 1250 ◦C), followed by air quenching. XRD analysis along with Le-Bail refinement confirms that 1100 ◦C and 1250 ◦C sintered oxides comprised of a single cubic spinel phase (Fd3m), while 1000 ◦C sintered oxide contains constituent oxides and a spinel phase. The phase formation of oxides sintered at 1100 ◦C and 1250 ◦C has also been confirmed by Raman spectroscopic analysis. Microstructural analysis revealed that the aggregated particle size increases with the rise in sintering temperature. With the change in sintering temperature, the dielectric behavior of the ceramic changed extensively. The 1100 ◦C sintered ceramic exhibits high frequency-dependent behavior, whereas the 1250 ◦C sintered ceramic yields low frequency-dependent behavior. The 1250 ◦C sintered HEO exhibits low-loss tangent (tan δ = 0.01) with higher dielectric permittivity (εʹ = 44) at high frequency (1 MHz) compared to the 1100 ◦C sintered ceramic and many other conventional dielectrics.
Fractal concept and impedance analysis have been employed to correlate the microstructure-dielectric property relation of (Co0.2Fe0.2Ni0.2Al0.2Ti0.2)3O4 spinel HEOs. The found Hurst exponent values for both different temperature-sintered HEOs are less than 0.5, indicating the anti-persistent behavior. This signifies that the height variations at neighboring pixels are negatively correlated. The present work is of fundamental importance in employing fractal analysis for the first time on spinel HEOs and correlating their properties. It also shows that processing conditions can effectively tailor the dielectric properties of the materials.
KW - Multi-cations high entropy oxide
KW - Mechanochemistry
KW - Spinel structure
KW - Fractal and impedance spectroscopic analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647584
DO - https://doi.org/10.1016/j.ceramint.2025.09.256
SN - 0272-8842
VL - 51
IS - 27
SP - 55341
EP - 55354
PB - Elsevier Ltd.
AN - OPUS4-64758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Standl, Jacob
A1 - Ryll, Tom W.
A1 - Schwab, Alexander
A1 - Prinz, Carsten
A1 - Wolf, Jakob B.
A1 - Kruschwitz, Sabine
A1 - Emmerling, Franziska
A1 - Völker, Christoph
A1 - Stawski, Tomasz M.
T1 - High-Entropy Phosphate Synthesis: Advancements through Automation and Sequential Learning Optimization
N2 - Transition metal phosphates (TMPs) are extensively explored for electrochemical and catalytical applications due to their structural versatility and chemical stability. Within this material class, novel high-entropy metal phosphates (HEMPs)─containing multiple transition metals combined into a single-phase structure─are particularly promising, as their compositional complexity can significantly enhance functional properties. However, the discovery of suitable HEMP compositions is hindered by the vast compositional design space and complex or very specific synthesis conditions. Here, we present a data-driven strategy combining automated wet-chemical synthesis with a Sequential Learning App for Materials Discovery (SLAMD) framework (Random Forest regression model) to efficiently explore and optimize HEMP compositions. Using a limited set of initial experiments, we identified multimetal compositions in a single-phase crystalline solid. The model successfully predicted a novel Co0.3Ni0.3Fe0.2Cd0.1Mn0.1 phosphate octahydrate phase, validated experimentally, demonstrating the effectiveness of the machine learning approach. This work highlights the potential of integrating automated synthesis platforms with data-driven algorithms to accelerate the discovery of high-entropy materials, offering an efficient design pathway to advanced functional materials.
KW - Metal phosphates
KW - High entropy
KW - Sequential learning
KW - Automated synthesis
KW - MAP
KW - Random forest
KW - Machine learning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641554
DO - https://doi.org/10.1021/acs.cgd.5c00549
SN - 1528-7483
VL - 25
IS - 19
SP - 7989
EP - 8001
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-64155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Batteas, James
A1 - Blank, Kerstin G.
A1 - Colacino, Evelina
A1 - Emmerling, Franziska
A1 - Friščić, Tomislav
A1 - Mack, James
A1 - Moore, Jeffrey
A1 - Rivas, Maria Elena
A1 - Tysoe, Wilfred
T1 - Moving mechanochemistry forward
N2 - Arguably mechanochemistry is one of the oldest, and at the same time one of the newest, areas of chemistry. One of the oldest, because it has been theorized that early hominids were able to develop rapidly due to their ability to heat and mechanically process their food to make it easier to digest. Old, because the ancient Greeks knew that mechanically activating stones (consisting of cinnabar) with vinegar in a copper pestle and mortar caused them to convert into mercury. We might be forgiven for thinking that this could have led our alchemical forbears to wonder if there were other stones that might also be persuaded to convert into gold. Early chemical luminaries such as Michael Faraday and Wilhelm Röntgen dabbled in mechanochemistry. However, in the late 19th and early 20th centuries, the field developed separately in many areas. Perhaps most significantly, synthetic chemists realized that reactions could be carried out with surprisingly high yields and selectivities by shaking them in a ball mill, and that they could even make novel compounds that their colleagues just using heat were not able to. Physicists were mechanically rearranging atoms into new configurations (i.e., doing chemistry) using exotic means such as atomic force microscope tips and optical tweezers. Scientists and engineers studying the formation of lubricious and anti-wear films realized that they were mechanochemically formed. Biochemists found molecular motor proteins, such as myosin and kinesin, that were able to convert chemical energy into motion or, vice versa, mechanical energy into the biochemical energy storage molecule adenosine triphosphate. In 2023, this confluence of advances convinced the Royal Society of Chemistry that the time was ripe to establish a new journal dedicated to the field of mechanochemistry. It is rare that a journal has the privilege of helping to create a new sub-branch of chemistry but, having done so, it has the obligation of helping to define the field and, optimistically, suggesting how the field might develop. This editorial has two major goals. The first is to bring to the attention of the scientific community the challenges faced by the field to set people thinking about how they might contribute and, second, to form the basis for more thorough discussions in the future. The sub-topics below outline current thoughts brought forward from members of our editorial board. We lay out areas and topics here with the intent of establishing a new editorial series, which we invite the community to contribute to, and outline topics and hopefully lay out challenges, which will enable us as a community to come together to move mechanochemistry forward.
KW - Mechanochemistry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646086
DO - https://doi.org/10.1039/d4mr90021a
SN - 2976-8683
VL - 2
IS - 1
SP - 10
EP - 19
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferreira, Daniela R.
A1 - Portet, Anaïs
A1 - Alves, Paula C.
A1 - Rijo, Patrícia
A1 - Gomes, Clara S. B.
A1 - Duarte, M. Teresa
A1 - Halasz, Ivan
A1 - Colacino, Evelina
A1 - Emmerling, Franziska
A1 - André, Vânia
T1 - Modulating the crystalline forms of silver–sulfadiazine complexes by mechanochemistry
N2 - Mechanochemical synthesis of pharmaceutical compounds has gained significant attention due to its potential to overcome traditional synthetic challenges while offering the possibility of improving the physicochemical properties of drugs. This study delves into the mechanochemical synthesis of silver sulfadiazine (AgSD) coordination compounds, obtained under different mechanochemical stress and processing conditions. The aim of this work was to investigate the influence of mechanochemical conditions on the selectivity in the preparation of AgSD coordination compounds. Through a series of experiments, we demonstrate the successful synthesis of two different AgSD coordination networks, using high-energy ball milling. By strategically manipulating the starting materials and milling parameters — including milling time, milling frequency, type of mechanical stress (as determined by different milling devices), and the presence of co-milling agents — we were able to control the product outcome. As a result, we achieved two different forms of silver-sulfadiazine metal frameworks, one of which was not previously disclosed. The crystal structure of the new form, obtained from high resolution PXRD synchrotron data, was compared with the previously known structure of a silver sulfadiazine compound. The in-depth antimicrobial activity systematic study of these AgSD forms on the generic systems showed increased antibacterial activity when compared to sulfadiazine. This research sheds light on the mechanochemical synthesis of silver sulfadiazine complexes. The obtained knowledge may guide the development of novel synthetic strategies for other drug molecules, leading to improved drug performance, stability, and therapeutic outcomes.
KW - Mechanochemistry
KW - Structure solution
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646099
DO - https://doi.org/10.1039/d5ce00572h
SN - 1466-8033
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Ballesteros, Menta
A1 - Ruiz Salvador, A. Rabdel
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Mechanochemical ZIF-9 formation: in situ analysis and photocatalytic enhancement evaluation
N2 - Efficient treatment of persistent pollutants in wastewater is crucial for sustainable water management and environmental protection. This study addresses this challenge by investigating the mechanochemical synthesis and photocatalytic performance of ZIF-9, a cobalt-based zeolitic imidazolate framework. Using synchrotron-based powder X-ray diffraction, we provide real-time insights into the formation dynamics of ZIF-9 during mechanosynthesis. Our results show that mechanochemically synthesised ZIF-9 exhibits superior photocatalytic activity compared to its solvothermally prepared counterpart, achieving a 2-fold increase in methylene blue degradation rate. This research not only advances our understanding of the synthesis and properties of ZIF-9, but also demonstrates the potential of mechanochemical approaches in the development of high-performance, sustainably produced materials for water treatment and other environmental applications.
KW - MOFs
KW - ZIF
KW - Time-resolved in situ investigation
KW - Photocatalysis synchrotron X-ray powder diffraction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641416
DO - https://doi.org/10.1039/D4MR00114A
SN - 2976-8683
VL - 2
IS - 1
SP - 116
EP - 126
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lopes, Chrystal
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Leyssens, Tom
A1 - Dupray, Valérie
A1 - Brandel, Clement
A1 - Cartigny, Yohann
T1 - Efficient racemization of the pharmaceutical compound Levetiracetam using solvent-free mechanochemistry
N2 - We present the racemization of an active pharmaceutical ingredient Levetiracetam using a novel approach. We demonstrate the design of a 100% solvent-free process that proceeds by high energy milling inside a regular mixer mill. The kinetics of the racemization process is drastically improved compared to the solution-based approach and illustrates the tremendous potential of mechanochemistry. In this study, we highlight the importance of mixing efficiency regarding data reproducibility, and we show, in particular, that water contamination has a negative impact on the reaction rate. Moreover, in situ X-ray diffraction gives us first insights into the mechanisms involved in the solid state during the mechanochemical racemization process.
KW - Mechanochemistry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646108
DO - https://doi.org/10.1039/d4mr00103f
SN - 2976-8683
VL - 2
IS - 1
SP - 83
EP - 90
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macchietti, Laura
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Braga, Dario
A1 - Grepioni, Fabrizia
T1 - Deriving kinetic insights from mechanochemically synthesized compounds using multivariate analysis (MCR-ALS) of powder X-ray diffraction data
N2 - Kinetics information on the progress of the mechanochemical reactions is key to their understanding and subsequent scale-up. For crystalline materials, the most robust and tested method for obtaining kinetic data is the Quantitative Phase Analysis (QPA) via Rietveld refinement. In this work, we tested the feasibility of the Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) method on powder X-ray diffraction (PXRD) data of mechanochemical processes by studying the system theophylline (TP) and malonic acid (MA) in a 1 : 1 stoichiometric ratio at different milling conditions. We have highlighted the strengths and weaknesses of the MCR-ALS method, and we demonstrated why it may be an alternative route to obtain quantitative information on mechanochemical kinetics.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646115
DO - https://doi.org/10.1039/d3mr00013c
SN - 2976-8683
VL - 1
IS - 1
SP - 106
EP - 115
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavlidis, Sotirios
A1 - Teutloff, Christian
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Krause, Konstantin B.
A1 - Emmerling, Franziska
A1 - Bittl, Robert
A1 - Abbenseth, Josh
T1 - A Crystalline Bismuth(II) Radical Anion: Synthesis, Characterization, and Reactivity
N2 - AbstractWe report the synthesis of a planarized tris‐amidobismuthane supported by a rigid, bulky NNN pincer ligand, which enforces a T‐shaped geometry at the bismuth center. The Bi(NNN) complex features a low‐lying LUMO with distinct Bi(6p) orbital character as shown by DFT calculations. Cyclic voltammetry reveals a fully reversible one‐electron reduction at E1/2 = –1.85 V versus Fc0/+ in THF. Chemical reduction with KC8 in the presence of 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane (222‐crypt) enables the isolation of an unprecedented Bi(II) radical anion in high isolated yields. Multi‐frequency EPR, X‐ray absorption spectroscopy and SQUID magnetometry complemented by theoretical calculations confirm localization of the unpaired electron on the bismuth center. Preliminary reactivity studies display radical reactivity as shown by single‐electron transfer chemistry and radical coupling reactions.
KW - Bi(III)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644143
DO - https://doi.org/10.1002/anie.202515545
SN - 1433-7851
VL - 64
IS - 49
SP - 1
EP - 6
PB - Wiley VHC-Verlag
AN - OPUS4-64414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chapartegui-Arias, Ander
A1 - Raysyan, A.
A1 - Belenguer, A. M.
A1 - Jaeger, Carsten
A1 - Tchipilov, Teodor
A1 - Prinz, Carsten
A1 - Abad Andrade, Carlos Enrique
A1 - Beyer, S.
A1 - Schneider, Rudolf
A1 - Emmerling, Franziska
T1 - Tailored mobility in a zeolite imidazolate framework (ZIF) antibody conjugate
N2 - Zeolitic imidazolate framework (ZIF) hybrid fluorescent nanoparticles and ZIF antibody conjugates have been synthesized, characterized, and employed in lateral-flow immunoassay (LFIA). The bright fluorescence of the conjugates and the possibility to tailor their mobility gives a huge potential for diagnostic assays. An enzyme-linked immunosorbent assay (ELISA) with horseradish peroxidase (HRP) as label, proved the integrity, stability, and dispersibility of the antibody conjugates, LC-MS/MS provided evidence that a covalent link was established between these metal-organic frameworks and lysine residues in IgG antibodies.
KW - ZIF
KW - ELISA
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532096
DO - https://doi.org/10.1002/chem.202100803
SN - 0947-6539
SN - 1521-3765
VL - 27
IS - 36
SP - 9414
EP - 9421
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Casali, L.
A1 - Broll, V.
A1 - Ciurili, S.
A1 - Braga, D.
A1 - Emmerling, Franziska
A1 - Gepioni, F.
T1 - Facilitating Nitrification Inhibition through Green, Mechanochemical Synthesis of a Novel Nitrapyrin Complex
N2 - Nitrapyrin (NP) is applied to cultivated soils to inhibit the enzymatic activity of ammonia monooxygenase (AMO), but its poor aqueous solubility and high volatility severely limit its application. β-Cyclodextrin (β-CD) is commonly used to form inclusion complexes with hydrophobic molecules, improving water solubility and stability upon complexation. Here we report on the mechanochemical synthesis of the inclusion complex β-CD·NP, characterized via a combination of solid-state techniques, including exsitu and in situ X-ray diffraction, Raman and NMR spectroscopies, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The pure inhibitor NP was also structurally characterized. The β-CD·NP complex presents improved solubility and thermal stability, and still inhibits the enzymatic activity of AMO with high efficacy. All results indicate that the inclusion of NP into β-CD represents a viable route for the preparation of a novel class of inhibitors, with improved properties related to stability, water solubility, and good inhibition activity.
KW - Mechanochemistry
KW - Nitrification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537154
DO - https://doi.org/10.1021/acs.cgd.1c00681
SN - 1528-7505
VL - 21
IS - 10
SP - 5792
EP - 5799
PB - ACS Publications
AN - OPUS4-53715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Wendt, R.
A1 - Kunkel, B.
A1 - Radnik, Jörg
A1 - Hoell, A.
A1 - Wohlrab, S.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
T1 - Size-Tunable Ni–Cu Core–Shell Nanoparticles—Structure, Composition, and Catalytic Activity for the Reverse Water–Gas Shift Reaction
N2 - A facile and efficient methodology is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core–shell nanoparticles (NPs) for application in catalysis. The diameter of the NPs is tuned in a range from 6 nm to 30 nm and to adjust the Ni:Cu ratio from 30:1 to 1:1. Furthermore, the influence of different reaction parameters on the final NPs is studied. The NPs are structurally characterized by a method combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Using these analytical methods, it is possible to elucidate a core–shell–shell structure of all particles and their chemical composition. In all cases, a depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core–shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction) independent of size and Ni:Cu ratio.
KW - Nanoparticles
KW - Core-shell
KW - Catalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543606
DO - https://doi.org/10.1002/adem.202101308
SN - 1438-1656
SP - 1
EP - 13
PB - Wiley VCH
AN - OPUS4-54360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Topolniak, Ievgeniia
A1 - Silbernagl, Dorothee
A1 - Altmann, Korinna
A1 - Sturm, Heinz
T1 - Long-time behavior of surface properties of microstructures fabricated by multiphoton lithography
N2 - The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems.
KW - Multiphoton lithography
KW - Additive manufacturing
KW - Microfabrication
KW - SZ2080 negative photo-resist
KW - Young´s modulus
KW - Aging
KW - Surface properties
KW - X-ray photoelectron spectroscopy
KW - Atomic force microscopy
KW - Force-distance-curve
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542166
DO - https://doi.org/10.3390/nano11123285
SN - 2079-4991
VL - 11
IS - 12
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-54216
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Axel
A1 - Altmann, Korinna
A1 - Kocher, B.
A1 - Braun, U.
T1 - Determination of tire wear markers in soil samples and their distribution in a roadside soil
N2 - Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0–2, 2–5, 5–10, and 10–20 cm. Four fine fractions, 1 000–500, 500–100, 100–50, and <50 μm, were analyzed.
TW contents based on SBR ranged from 155 to 15 898 mg kg−1. TW contents based on zinc were between 413 and 44 812 mg kg−1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance.
The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.
KW - Microplastic
KW - TED-GC/MS
KW - Tire wear
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543344
DO - https://doi.org/10.1016/j.chemosphere.2022.133653
VL - 294
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-54334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Kabelitz, Anke
A1 - Schokel, Alexander
A1 - Wagner, Ralf
A1 - Prinz, Carsten
A1 - Kemnitz, E
A1 - Emmerling, Franziska
A1 - Krahl, Thoralf
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Local Structure of Europium-Doped Luminescent Strontium Fluoride Nanoparticles: Comparative X-ray Absorption Spectroscopy and Diffraction Study
N2 - Rare-earth based luminescent materials are key functional components for the rational design of light-conversion smart devices. Stable Eu3+-doped strontium fluoride (SrF2) nanoparticles were prepared at room temperature in ethylene glycol. Their luminescence depends on the Eu content and changes after heat treatment. The crystallinity of heat-treated material increases in comparison with as-synthesized samples. Particles were investigated in solution using X-ray diffraction, small-angle X-ray scattering, and X-ray spectroscopy. After heat treatment, the size of the disordered nanoparticles increases together with a change of their local structure. Interstitial fluoride ions can be localized near Eu3+ ions. Therefore, non-radiative relaxation from other mechanisms is decreased. Knowledge about the cation distribution is key information for understanding the luminescence properties of any material.
KW - SrF2
KW - EXAFS
KW - Eu
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540094
DO - https://doi.org/10.1002/cnma.202100281
VL - 7
IS - 11
SP - 1221
EP - 1229
PB - Wiley Online Library
AN - OPUS4-54009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lampronti, G.
A1 - Michalchuk, Adam
A1 - Mazzeo, P.
A1 - Belenguer, Ana
A1 - Sanders, J. K. M.
A1 - Bacchi, A.
A1 - Emmerling, Franziska
T1 - Changing the game of time resolved X-ray diffraction on the mechanochemistry playground by downsizing
N2 - Time resolved in situ (TRIS) monitoring has revolutionised the study of mechanochemical transformations but has been limited by available data quality. Here we report how a combination of miniaturised grinding jars together with innovations in X-ray powder diffraction data collection and state-of-the-art analysis strategies transform the power of TRIS synchrotron mechanochemical experiments. Accurate phase compositions, comparable to those obtained by ex situ measurements, can be obtained with small sample loadings. Moreover, microstructural parameters (crystal size and microstrain) can be also determined with high confidence. This strategy applies to all chemistries, is readily implemented, and yields high-quality diffraction data even using a low energy synchrotron source. This offers a direct avenue towards the mechanochemical investigation of reactions comprising scarce, expensive, or toxic compounds. Our strategy is applied to model systems, including inorganic, metal-organic, and organic mechanosyntheses, resolves previously misinterpreted mechanisms in mechanochemical syntheses, and promises broad, new directions for mechanochemical research.
KW - Mechanochemistry
KW - Synchrotron radiation
KW - Material synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535932
DO - https://doi.org/10.1038/s41467-021-26264-1
SN - 2041-1723
VL - 12
IS - 1
SP - 1
EP - 9
PB - Nature Publishing Group
CY - London
AN - OPUS4-53593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Michalchuk, Adam
A1 - Schröder, V.
A1 - List-Kratochvil, E.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Elastic Flexibility in an Optically Active Naphthalidenimine-Based Single Crystal
N2 - Organic single crystals that combine mechanical flexibility and optical properties are important for developing flexible optical devices, but examples of such crystals remain scarce. Both mechanical flexibility and optical activity depend on the underlying crystal packing and the nature of the intermolecular interactions present in the solid state. Hence, both properties can be expected to be tunable by small chemical modifications to the organic molecule. By incorporating a chlorine atom, a reportedly mechanically flexible crystal of (E)-1-(4-bromo-phenyl)iminomethyl-2-hydroxylnaphthalene (BPIN) produces (E)-1-(4-bromo-2-chloro-phenyl)iminomethyl-2-hydroxyl-naphthalene (BCPIN). BCPIN crystals show elastic bending similar to BPIN upon mechanical stress, but exhibit a remarkable difference in their optical properties as a result of the chemical modification to the backbone of the organic molecule. This work thus demonstrates that the optical properties and mechanical flexibility of molecular materials can, in principle, be tuned independently.
KW - Elastic Crystal
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539040
DO - https://doi.org/10.3390/cryst11111397
VL - 11
IS - 11
SP - 1397
PB - MDPI
AN - OPUS4-53904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gernhard, M.
A1 - Rautenberg, Max
A1 - Hörner, G.
A1 - Weber, B.
A1 - Emmerling, Franziska
A1 - Roth, C.
T1 - Mechanochemical Synthesis as a Greener Way to ProduceIron-based Oxygen Reduction Catalysts
N2 - Iron-based catalysts have been reported manifold and studied as platinum group metal (PGM) free alternatives for the catalysis of the oxygen reduction reaction (ORR). However, their sustainable preparation by greener synthesis approaches is usually not discussed. In this work, we propose a new method for the sustainable preparation of such catalysts by using a mechanochemical approach, with no solvents and non-toxic chemicals. The materials obtained from low temperature carbonization (700 °C) exhibit considerable and stable catalytic performance for ORR in alkaline medium. A catalyst obtained
from iron hydroxide, tryptophan, dicyandiamide, and ammonium nitrate shows the best electrocatalytic Performance with an overpotential of 921 mV vs. RHE at 0.1 mA/cm2 and an electron transfer number of 3.4.
KW - PGM-free catalyst
KW - Oxygen Reduction Reaction
KW - AEMFC
KW - Mössbauer Spectroscopy
KW - Sustainable Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535326
DO - https://doi.org/10.1002/zaac.202100194
VL - 647
IS - 22
SP - 2080
EP - 2087
PB - Weinheim-VCH GmbH
AN - OPUS4-53532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Rudic, S.
A1 - Pulham, C.
A1 - Morrison, C.
T1 - Predicting the impact sensitivity of a polymorphic high explosive: the curious case of FOX-7
N2 - The impact sensitivity (IS) of FOX-7 polymorphs is predicted by phonon up-pumping to decrease as layers of FOX-7 molecules flatten. Experimental validation proved anomalous owing to a phase transition during testing, raising questions regarding Impact sensitivity measurement and highlighting the need for models to predict IS of polymorphic energetic materials.
KW - Energetic materials
KW - Density functional theory
KW - Inelastic Neutron Scattering Spectroscopy
KW - Impact Sensitivity
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535558
DO - https://doi.org/10.1039/d1cc03906g
SN - 1364-548X
VL - 57
IS - 85
SP - 11213
EP - 11216
PB - Royal Society of Chemistry
AN - OPUS4-53555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Loges, A.
A1 - Scholz, G.
A1 - de Sousa Amadeu, Nader
A1 - Jingjing, S.
A1 - Emmerling, Franziska
A1 - John, T.
A1 - Paulus, B.
A1 - Braun, T.
T1 - Studies on the local structure of the F/OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy
N2 - he mutual influence of F and OH groups in neighboring sites in topaz (Al2SiO4(F,OH)2) was investigated using magic angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The splitting of 19F and 1H NMR signals, as well as the OH Raman band, provides evidence for hydrogen bond formation within the crystal structure. Depending on whether a given OH group has another OH group or fluoride as its neighbor, two different hydrogen bond constellations may form: either OH···O···HO or F···H···O. The proton accepting oxygen was determined to be part of the SiO4 tetrahedron using 29Si MAS NMR. Comparison of the MAS NMR data between an OH-bearing and an OH-free topaz sample confirms that the 19F signal at −130 ppm stems from F− ions that take part in H···F bonds with a distance of ∼ 2.4 Å, whereas the main signal at −135 ppm belongs to fluoride ions with no immediate OH group neighbors. The Raman OH sub-band at 3644 cm−1 stems from OH groups neighboring other OH groups, whereas the sub-band at 3650 cm−1 stems from OH groups with fluoride neighbors, which are affected by H···F bridging. The integrated intensities of these two sub-bands do not conform to the expected ratios based on probabilistic calculations from the total OH concentration. This can be explained by a difference in the polarizability of the OH bond between the different hydrogen bond constellations or partial order or unmixing of F and OH, or a combination of both. This has implications for the quantitative interpretation of Raman data on OH bonds in general and their potential use as a probe for structural (dis-)order. No indication of tetrahedrally coordinated Al was found with 27Al MAS NMR, suggesting that the investigated samples likely have nearly ideal Al/Si ratios, making them potentially useful as high-density electron microprobe reference materials for Al and Si, as well as for F.
KW - Topas
KW - NMR
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561863
DO - https://doi.org/10.5194/ejm-34-507-2022
SN - 1617-4011
VL - 34
IS - 5
SP - 507
EP - 521
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-56186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mazzeo, P. P.
A1 - Prencipe, M.
A1 - Feiler, Torvid
A1 - Emmerling, Franziska
A1 - Bacchi, A.
T1 - On the mechanism of cocrystal mechanochemical reaction via low melting eutectic: A time-resolved in situ monitoring investigation
N2 - Mechanochemistry has become a sustainable and attractive cost-effective synthetic technique, largely used within the frame of crystal engineering. Cocrystals, namely, crystalline compounds made of different chemical entities within the same crystal structure, are typically synthesized in bulk via mechanochemistry; however, whereas the macroscopic aspects of grinding are becoming clear, the fundamental principles that underlie mechanochemical cocrystallization at the microscopic level remain poorly understood. Time-resolved in situ (TRIS) monitoring approaches have opened the door to exceptional detail regarding mechanochemical reactions. We here report a clear example of cocrystallization between two solid coformers that proceeds through the formation of a metastable low melting binary eutectic phase. The overall cocrystallization process has been monitored by time-resolved in situ (TRIS) synchrotron X-ray powder diffraction with a customized ball milling setup, currently available at μ Spot beamline at BESSY-II, Helmholtz-Zentrum Berlin. The binary system and the low melting eutectic phase were further characterized via DSC, HSM, and VT-XRPD.
KW - Mechanochemistry
KW - In situ
KW - Cocrystal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552977
DO - https://doi.org/10.1021/acs.cgd.2c00262
SN - 1528-7505
VL - 22
IS - 7
SP - 4260
EP - 4267
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-55297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pakrashy, S.
A1 - Mandal, P. K.
A1 - Goswami, J. N.
A1 - Dey, S. K.
A1 - Choudhury, S. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Alasmary, F. A.
A1 - Dolai, M.
T1 - Bioinformatics and Network Pharmacology of the First Crystal Structured Clerodin: Anticancer and Antioxidant Potential against Human Breast Carcinoma Cell
N2 - Clerodin was isolated from the medicinal plant Clerodendrum infortunatum, and CSD search showed the first crystal structure of clerodin by a single-crystal X-ray diffraction study. We checked its binding potential with target proteins by docking and conducted network pharmacology analysis, ADMET analysis, in silico pathway analysis, normal mode analysis (NMA), and cytotoxic activity studies to evaluate clerodin as a potential anticancer agent. The cell viability studies of clerodin on the human breast carcinoma cell line (MCF-7) showed toxicity on MCF-7 cells but no toxicity toward normal human lymphocyte cells (HLCs). The anticancer mechanism of clerodin was validated by its enhanced capacity to produce intracellular reactive oxygen species (ROS) and to lower the reduced glutathione content in MCF-7 cells.
KW - Anticancer
KW - Clerodin
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567600
DO - https://doi.org/10.1021/acsomega.2c07173
SN - 2470-1343
VL - 7
IS - 51
SP - 48572
EP - 48582
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abusafia, A.
A1 - Scheid, C.
A1 - Meurer, Maren
A1 - Altmann, Korinna
A1 - Dittmer, U.
A1 - Steinmetz, H.
T1 - Microplastic sampling strategies in urban drainage systems for quantification of urban emissions based on transport pathways
N2 - Tracking waterborne microplastic (MP) in urban areas is a challenging task because of the various sources and transport pathways involved. Since MP occurs in low concentrations in most wastewater and stormwater streams, large sample volumes need to be captured, prepared, and carefully analyzed. The recent research in urban areas focused mainly on MP emissions at wastewater treatment plants (WWTPs), as obvious entry points into receiving waters. However, important transport pathways under wet-weather conditions are yet not been investigated thoroughly. In addition, the lack of comprehensive and comparable sampling strategies complicated the attempts for a deeper understanding of occurrence and sources. The goal of this paper is to (i) introduce and describe sampling strategies for MP at different locations in a municipal catchment area under dry and wet-weather conditions, (ii) quantify MP emissions from the entire catchment and two other smaller ones within the bigger catchment, and (iii) compare the emissions under dry and wet-weather conditions. WWTP has a high removal rate of MP (>96%), with an estimated emission rate of 189 kg/a or 0.94 g/[population equivalents (PEQ · a)], and polyethylene (PE) as the most abundant MP. The specific dry-weather emissions at a subcatchment were ≈30 g/(PEQ · a) higher than in the influent of WWTP with 23 g/(PEQ · a). Specific wet-weather emissions from large sub-catchment with higher traffic and population densities were 1952 g/(ha · a) higher than the emissions from smaller catchment (796 g/[ha · a]) with less population and traffic. The results suggest that wet-weather transport pathways are likely responsible for 2–4 times more MP emissions into receiving waters compared to dry-weather ones due to tire abrasion entered from streets through gullies. However, more investigations of wet-weather MP need to be carried out considering additional catchment attributes and storm event characteristics.
KW - Combined sewer system
KW - Large volume samplers
KW - Microplastic pollution
KW - Separate sewer system
KW - Stormwater retention tank
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568271
DO - https://doi.org/10.1002/appl.202200056
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, S.
A1 - Horstmann, J.
A1 - Altmann, Korinna
A1 - Braun, U.
A1 - Hagendorf, C.
T1 - A reference methodology for microplastic particle size distribution analysis: Sampling, filtration, and detection by optical microscopy and image processing
N2 - Microplastic (MP) contamination in natural water circulation is a concern for environmental issues and human health. Various types of polymer materials have been identified and were detected in MP analytic test procedures. Beyond MP polymer type, particle size and form play a major role in water analysis due to possible negative toxicologic effects on flora and fauna. However, the correct quantitative measurement of MP size distribution over several orders of magnitude is strongly influenced by sample preparation, filtration materials and processes, and microanalytical techniques, as well as data acquisition and analysis. In this paper, a reference methodology is presented aiming at an improved quantitative analysis of MP particles. An MP analysis workflow is demonstrated including all steps from reference materials to sample preparation, filtration handling, and MP particle size distribution analysis. Background-corrected particle size distributions (1–1000 µm) have been determined for defined polyethylene (PE) and polyethylene terephthalate (PET) reference samples. Microscopically measured particle numbers and errors have been cross-checked with the total initial mass. In particular, defined reference MP samples (PE, PET) are initially characterized and applied to filtration experiments. Optical microscopy imaging on full-area Si filters with subsequent image analysis algorithms is used for statistical particle size distribution analysis. To quantify the effects of handling and filtration, several blind tests with distilled water are carried out to determine the particle background for data evaluation. Particle size distributions of PE and PET reference samples are qualitatively and quantitatively reproduced with respect to symmetry, and maximum and cut-off diameter of the distribution. It is shown that especially MP particles with a radius of >50 µm can be detected and retrieved with high reliability. For particle sizes <50 µm, a significant interference with background contamination is observed. Data from blank samples allows a correction of background contaminations. Furthermore, for enhanced sampling statistics, the recovery of the initial amount of MP will be qualitatively shown. The results are intended as an initial benchmark for MP analytics quality. This quality is based on statistical MP particle distributions and covers the complete analytic workflow starting from sample preparation to filtration and detection. Microscopic particle analysis provides an important supplement for the evaluation of established spectroscopic methods such as Fourier-transform infrared spectroscopy or Raman spectroscopy.
KW - Drinking water
KW - Filtration
KW - Microplastics detection
KW - Quality control
KW - Statistical particle distribution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567625
DO - https://doi.org/10.1002/appl.202200055
SN - 2702-4288
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Witt, Julia
A1 - Jain, Mohit
A1 - Emmerling, Franziska
T1 - In situ time-resolved monitoring of mixed-ligand metal–organic framework mechanosynthesis
N2 - The mechanism of mixed-ligand metal–organic framework (MOF) formation, and the possible role of intermediate single-ligand metal complexes during mechanosynthesis, have not been explored yet. For the first time, we report here in situ real-time monitoring of the mechanochemical formation mechanism of mixed-ligand MOFs. Our results show that binary phases can act as intermediates or competing products in one-pot and stepwise synthesis.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - In situ X-ray diffraction
KW - Mixed-ligand MOFs
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558167
DO - https://doi.org/10.1039/D2CE00803C
SP - 1
EP - 4
PB - Royal Society of Chemistry
AN - OPUS4-55816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Hoch, C.
T1 - Laudatio Prof. Dr.-Ing. Caroline Röhr
N2 - It is a laudatio on the ocations of Prof. Dr.-Ing. Caroline Röhrs 60th birthday.
KW - Metal-oxides
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561877
DO - https://doi.org/10.1002/zaac.202200159
SN - 0044-2313
VL - 648
IS - 10
SP - 1
EP - 2
PB - John Wiley & Sons, Ltd
AN - OPUS4-56187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kadri, Lena
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Tajber, Lidia
T1 - Mechanochemical comparison of ball milling processes for levofloxacin amorphous polymeric systems
N2 - This study aimed to investigate the amorphization capabilities of levofloxacin hemihydrate (LVXh), a fluoroquinolone drug, using a polymer excipient, Eudragit® L100 (EL100). Ball milling (BMing) was chosen as the manufacturing process and multiple mill types were utilized for comparison purposes. The product outcomes of each mill were analyzed in detail. The solid-state of the samples produced was comprehensively characterized by Powder X-ray Diffraction (PXRD), In-situ PXRD, Differential Scanning Calorimetry (DSC), Solid-State Fourier Transform Infrared Spectroscopy (FT-IR), and Dynamic Vapor Sorption (DVS). The crystallographic planes of LVXh were investigated by in-situ PXRD to disclose the presence or absence of weak crystallographic plane(s). The mechanism of LVXh:EL100 system formation was discovered as a two-step process, first involving amorphization of LVXh followed by an interaction with EL100, rather than as an instantaneous process. DVS studies of LVXh:EL100 samples showed different stability properties depending on the mill used and % LVXh present. Overall, a more sustainable approach for achieving full amorphization of the fluoroquinolone drug, LVXh, was accomplished, and advancements to the fast-growing world of pharmaceutical mechano- and tribo-chemistry were made.
KW - Levofloxacin
KW - Eudragit® L100
KW - Mechanochemistry
KW - Phase transformation
KW - In situ monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611129
DO - https://doi.org/10.1016/j.ijpharm.2024.124652
SN - 0378-5173
VL - 665
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-61112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baláž, Matej
A1 - Birinci, Mustafa
A1 - Şentürk, Kader
A1 - Achimovičová, Marcela
A1 - Baláž, Peter
A1 - Tampubolon, Imelda Octa
A1 - Stolar, Tomislav
A1 - Bienert, Ralf
A1 - Emmerling, Franziska
A1 - Erdemoğlu, Sema
A1 - Sis, Hikmet
A1 - Erdemoğlu, Murat
T1 - Utilizing Taguchi method and in situ X-ray powder diffraction monitoring to determine the influence of mechanical activation conditions on the physico-chemical properties and Al leachability of K-feldspar
N2 - K-feldspar represents an important natural resource of potassium and aluminum. Within the framework of this study, the K-feldspar was mechanically activated in a planetary ball mill under different conditions planned according to 43 Taguchi orthogonal array experimental design. As outputs, specific surface area (SBET), median particle size (d50), amorphization degree of mineral phases , and Al recovery were used. It was found that the initial d50 value of 293 μm could be reduced to 6.7 μm and the SBET value of 4.7 m2/g could be increased up to 32.5 m2/g upon milling. Both microcline KAl3SiO8, and albite NaAl3SiO8 could be almost completely amorphized, whereas quartz SiO2 still maintained some crystallinity even under the most intensive conditions. Increasing SBET and decreasing the d50 values did not lead to a significant improvement in Al leach recovery, whereas a clear relationship between the amorphization of microcline and the recovered aluminum was found. Analysis of Variance (ANOVA) showed that increasing ball-to-powder ratio is the most beneficial for the improvement in Al recovery. In situ powder X-ray diffraction monitoring performed in an oscillation ball mill under synchrotron irradiation has shown very rapid amorphization of microcline phase at the beginning. However, amorphization of microcline was only partial after two hours of the treatment in this mill, apart from almost complete process in the planetary ball mill. In the end, regressions for the calculation of Al recovery by knowing the values of input parameters were calculated. In general, by just using mechanical activation without the subsequent roasting process that is commonly used to boost metal recoveries, it was possible to quantitatively recover aluminum from K-feldspar.
KW - Mechanochemistry
KW - Mechanical activation
KW - Design of experiments
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611059
DO - https://doi.org/10.1016/j.jmrt.2024.08.156
SN - 2238-7854
VL - 32
SP - 3886
EP - 3895
PB - Elsevier B.V.
AN - OPUS4-61105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Bogoclu, Can
A1 - Emmerling, Franziska
A1 - Streli, Christina
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach
N2 - In materials science, traditional techniques for analyzing layered structures are essential for obtaining information about local structure, electronic properties and chemical states. While valuable, these methods often require high vacuum environments and have limited depth profiling capabilities. The grazing exit x-ray absorption near-edge structure (GE-XANES) technique addresses these limitations by providing depth-resolved insight at ambient conditions, facilitating in situ material analysis without special sample preparation. However, GE-XANES is limited by long data acquisition times, which hinders its practicality for various applications. To overcome this, we have incorporated Bayesian optimization (BO) into the GE-XANES data acquisition process. This innovative approach potentially reduces measurement time by a factor of 50. We have used a standard GE-XANES experiment, which serve as reference, to validate the effectiveness and accuracy of the BO-informed experimental setup. Our results show that this optimized approach maintains data quality while significantly improving efficiency, making GE-XANES more accessible to a wider range of materials science applications.
KW - Machine Learning
KW - GE-XANES
KW - Bayesian Optimization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603955
DO - https://doi.org/10.1088/2632-2153/ad4253
VL - 5
IS - 2
SP - 1
EP - 12
PB - IOP Publishing
AN - OPUS4-60395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Coburger, Peter
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Abbenseth, Josh
T1 - Combining geometric constraint and redox non-innocence within an ambiphilic PBiP pincer ligand
N2 - The first pincer ligand featuring a strictly T-shaped pnictogen donor moiety was synthesised. The PBiP ligand's redox activity facilitates unprecedented ambiphilic bonding of the Bi centre with transition metals through the Bi(6p) orbital.
KW - EXAFS
KW - Pincer Ligand
KW - Group 15 metals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611113
DO - https://doi.org/10.1039/D4SC00197D
SN - 2041-6520
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Goldammer, Ole
A1 - Bader, Julia
A1 - Emmerling, Franziska
A1 - Riedel, Sebastian
T1 - Introducing AFS ([Al(SO3F)3]x) – a thermally stable, readily available, and catalytically active solid Lewis superacid
N2 - This paper introduces the thermally stable, solid Lewis superacid aluminium tris(fluorosulfate) (AFS), that is easy-to-synthesize from commercially available starting materials. Its applicability, e.g. in catalytic C–F bond activations, is shown.
KW - Lewis Acid
KW - C-F activation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601001
DO - https://doi.org/10.1039/D4SC01753F
SN - 2041-6520
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Prasenjit
A1 - Chakraborty, Gouri
A1 - Friese, Nico
A1 - Roeser, Jérôme
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Schmidt, Johannes
A1 - Thomas, Arne
T1 - Heteropolyaromatic Covalent Organic Frameworks via One-Pot Multicomponent Reactions
N2 - Multicomponent reactions (MCRs) offer a platform to create different chemical structures and linkages for highly stable covalent organic frameworks (COFs). As an illustrative example, the multicomponent Povarov reaction generates 2,4-phenylquinoline from aldehydes and amines in the presence of electron-rich alkenes. In this study, we introduce a new domino reaction to generate unprecedented 2,3-phenylquinoline COFs in the presence of epoxystyrene. This work thus presents, for the first time, structural isomeric COFs produced by multicomponent domino and Povarov reactions. Furthermore, 2,3-phenylquinolines can undergo a Scholl reaction to form extended aromatic linkages. With this approach, we synthesize two thermally and chemically stable MCR-COFs and two heteropolyaromatic COFs using both domino and in situ domino and Scholl reactions. The structure and properties of these COFs are compared with the corresponding 2,4-phenylquinoline-linked COF and imine-COF, and their activity toward benzene and cyclohexane sorption and separation is investigated. The position of the pendant phenyl groups within the COF pore plays a crucial role in facilitating the industrially important sorption and separation of benzene over cyclohexane. This study opens a new avenue to construct heteropolyaromatic COFs via MCR reactions.
KW - COF
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604038
DO - https://doi.org/10.1021/jacs.4c02551
SP - 1
EP - 9
PB - American Chemical Society (ACS)
AN - OPUS4-60403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiesner, Yosri
A1 - Hoffmann, Thomas
A1 - Range, David
A1 - Altmann, Korinna
T1 - Microplastics in sediments of the river Rhine—A workflow for preparation and analysis of sediment samples from aquatic river systems for monitoring purposes
N2 - AbstractMicroplastics (MP) can be detected in all environmental systems. Marine and terrestrial aquatic systems, especially the transported suspended solids, have often been the focus of scientific investigations in the past. Sediments of aquatic river systems, on the other hand, were often ignored due to the time‐consuming sample preparation and analysis procedures. Spectroscopic measurement methods counting particle numbers are hardly suitable as detection methods, because there are plenty of natural particles next to a small number of MP particles. Integral methods, such as thermoanalytical methods are determining the particle mass independently of the inorganic components.In this study, a workflow for sample preparation via density separation and subsequent analysis by thermal extraction desorption‐gas chromatography/mass spectrometry is presented, which leads to representative and homogeneous samples and allows fast and robust MP mass content measurements suitable for routine analysis. Polymers were identified and quantified in all samples. Polyethylene and styrene‐butadiene rubber are the dominant polymers, besides polypropylene and polystyrene. Overall, total polymer masses between 1.18 and 337.0 µg/g could be determined. Highest MP concentrations in riverbed sediment are found in sites characterized by low flow velocities in harbors and reservoirs, while MP concentrations in sandy/gravelly bed sediments with higher flow velocities are small.
KW - Microplastics
KW - Density separation
KW - TED-GC/MS
KW - NaI
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597335
DO - https://doi.org/10.1002/appl.202200125
VL - 3
IS - 2
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Seasonal microplastic concentrations along the rivers Rhine and Danube
N2 - Over the last 20 years, many researchers, politicians and citizens have become increasingly aware of the growing plastic problem of our time. A lack of recycling concepts and plastic collection points as well as careless dumping lead to accumulation of plastic products in the environment. Natural weathering can cause these plastics to degrade and fractionate, meaning that microplastics (1 1,000 µm, ISO/TR 21960:2020) and nanoplastics (< 1 µm, ISO/TR 21960:2020) of various synthetic polymer materials can now be detected in all parts of the world. Whether microplastics or nanoplastics pose a toxicological hazard is being investigated in a variety of ways. Valid results are still pending. However, the EU precautionary principle applies to micro- and nanoplastics. Monitoring of microplastics is already required in the revision of the Drinking Water and Wastewater Framework Directive.
Reliable monitoring of rivers can be carried out by sampling with sedimentation boxes and microplastic detection by using thermal extraction desorption gas chromatography/mass spectrometry (TED-GC/MS) in routine operation (Figure 1). The river Rhine was sampled for microplastic masses at three different sampling locations over a period of one year and in addition the Danube at randomized sampling locations The TED-GC/MS results showed that various synthetic polymers frequently produced in industry, such as polyethylene, polypropylene or polystyrene as well as the tire compound styrene-butadiene rubber were found. The work not only shows a possible workflow for monitoring concepts, but also provides information on environmentally relevant concentrations of microplastics and tire components in surface waters. This in turn is necessary for ecotoxicological studies.
T2 - ESOPS
CY - Berlin, Germany
DA - 09.09.2024
KW - Microplastics
KW - TED-GC/MS
KW - Polymer 3R
PY - 2024
AN - OPUS4-61016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Atanasova, Aleksandra
T1 - Herstellung und Einsatz neuartiger Trypsin-Partikel für den enzymatischen Antikörper-Verdau
N2 - In dieser Arbeit wurden zwei Trypsinvarianten, der Wildtyp (wtT) und eine thermostabile Variante (tsT), rekombinant hergestellt. Die Herstellung von Proteinen in Bakterien kann zu Fehlfaltungen und Einschlusskörperchen führen, weshalb eine geeignete Faltungsstrategie notwendig ist. In dieser Arbeit konnte eine schrittweise Vorgehensweise erfolgreich angewendet werden.
Nach der Ni-NTA-Aufreinigung wurde zusätzlich eine substratspezifische Benzamidin-Aufreinigung eingesetzt, um die Aktivität zu verbessern. Außerdem wurden die rekombinanten Trypsine auf Korund immobilisiert. Korund ist ein kostengünstiges Material, das nach Silanisierung und Glutaraldehyd-Kopplung für die Bindung von Proteinen geeignet gemacht wurde. Dabei konnte gezeigt werden, dass mehr wtT als tsT gebunden wurde, was sich auch in den Kopplungsdichte widerspiegelte.
Die immobilisierten Enzyme wurden in Bezug auf Aktivität, Wiederverwendbarkeit, Lagerfähigkeit und Temperaturstabilität untersucht. Beide Varianten zeigten vergleichbare Leistungen, wobei tsT bei höheren Temperaturen eine etwas bessere Stabilität aufwies. Für den Antikörperverdau wurden sowohl thermische als auch chemische Denaturierungen bei verschiedenen Temperaturen ( 37 °C und 60 °C) getestet. Die Analyse mit MALDI-TOF-MS zeigte, dass gute Werte für die Sequenzabdeckung erzielt werden konnten. Besonders die chemische Denaturierung führte zu besseren Ergebnissen mit weniger Selbstverdau.
Beim Vergleich mit kommerziell immobilisiertem Crude-Trypsin zeigten die rekombinanten Varianten eine höhere Spezifität und bessere Sequenzabdeckung bei gleichzeitig geringerem Selbstverdau. Die Wiederverwendbarkeit wurde durch fünf Verdauzyklen bei 37 °C überprüft. Dabei blieb die Aktivität weitgehend stabil, auch wenn die Peakintensität in den MALDI-Spektren mit jedem Zyklus abnahm. Eine eindeutige Zuordnung der Fingerprints des Antikörpers aus einer Bibliothek von über 90 Antikörpern war trotz dessen gegeben.
KW - Korund
KW - Immobilisierung
KW - Proteomik
KW - Rekombinante Proteine
KW - Thermostabile Enzyme
PY - 2025
SP - 1
EP - 86
CY - Berlin
AN - OPUS4-64433
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Béalu, Zoé
A1 - Walther, Johanna
A1 - Abusafia, Attaallah
A1 - Altmann, Korinna
A1 - Meurer, Maren
A1 - Gretzschel, Oliver
A1 - Schäfer, Michael
A1 - Steinmetz, Heidrun
T1 - Removal of Organic Micropollutants and Microplastics via Ozonation Followed by Granular Activated Carbon Filtration
N2 - Discharge from Wastewater Treatment Plants (WWTPs) can result in the emission of organic micropollutants (OMPs) and microplastics (MPs) into the aquatic environment. To prevent this harmful release, a pilot plant consisting of an ozonation followed by a granular activated carbon (GAC) filter was operated at a WWTP in Germany, and its side-effects on the concentrations of nitrogen (N) and phosphorous (P) compounds were measured. Over 80% of OMPs and transformation products were removed during the operating time (around 6000 bed volumes) no matter the ozone dose (from around 0.1 to 0.5 mgO3/mgDOC), except for Diatrizoic acid, whose breakthrough appeared at 3500 BV. Formation of the oxidation by-product, NDMA, increased with higher ozone doses, but the concentration remained below 100 ng/L. Bromate was formed at a higher ozone dose (0.4 mgO3/mgDOC) but at a low concentration—below 10 µg/L. The MP particles detected in the inflow (PE, SBR, PP, and PS) were effectively eliminated to a high degree, with a removal rate of at least 92%. Carbon parameters (COD, DOC, and SAC254) were removed further by the pilot plant, but to different extents. As expected, nitrate was formed during ozonation, while nitrite’s concentration decreased. Further, nitrite decreased and nitrate increased within the GAC filter, while ammonium was eliminated by at least 90%. Total P concentration decreased after the pilot, but the concentration of PO4-P increased.
KW - Microplastics
KW - TED-GC/MS
KW - Granular Activated Carbon Filtration
KW - Removal of Organic Micropollutants
KW - Wastewater treatment plant
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615209
DO - https://doi.org/10.3390/environments11110241
VL - 11
IS - 11
SP - 1
EP - 38
PB - MDPI AG
AN - OPUS4-61520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kittner, Maria
A1 - Bauer, Vanessa
A1 - Altmann, Korinna
A1 - Kraft, Oliver
A1 - Nordmann, Thomas
A1 - Kalbe, Ute
T1 - Mikroplastik-Austrage aus Kunststoffrasenplatzen ins Grundwasser
N2 - Sportplätze aus Kunststoffrasen haben sich im Breitensport etabliert, weshalb ihre Anzahl jährlich zunimmt. Dabei werden Umwelt- und Gesundheitsrisiken, insbesondere durch Mikroplastik-Austräge, kontrovers diskutiert. Um die ungenügende Datenlage zur Menge des Austrages an Mikroplastik zu verbessern, haben sich zwei individuelle Studien mit dieser Forschungsfrage mit Fokus auf den Boden-Grundwasser-Pfad befasst, deren Ergebnisse hier erstmalig gemeinsam vorgestellt werden. Die erste Studie simulierte unter Laborbedingungen Mikroplastik-Emissionen von drei Kunststoffrasen-Szenarien in unterschiedlichen Alterungszuständen und analysierte thermoanalytisch. Die zweite Studie untersuchte Grundwasser-Proben von zwei Realsportplätzen, die 1 m unter dem Grundwasserspiegel entnommen und spektroskopisch untersucht wurden. Dies ermöglicht erstmalig einen Vergleich von Mikroplastik-Austrägen über das Sickerwasser in verschiedenen Bodentiefen. Die Labor-Ergebnisse ergaben je nach Alterungszustand des Kunststoffrasenplatzes Mikroplastik-Emissionen zwischen < 0,1 μg/L und 26,8 μg/L in 30 cm Bodentiefe. Wohingegen in den Grundwasser-Proben der Realsportplätze ab 4 m Bodentiefe keine Kunststoffrasen-Partikel detektiert wurden. Dies deutet darauf hin, dass vermehrt Mikroplastik durch Alterung aus Kunststoffrasen entsteht und im Sickerwasser ausgetragen wird, aber der Boden Mikroplastik- Partikel ≥ 5 μm durch Filtrationseffekte zurückhält, sodass diese im Grundwasser nicht nachweisbar waren.
KW - Kunststoffrasen, Alterung, Mikroplastik, Elution, Schadstoffe
PY - 2025
DO - https://doi.org/10.37307/j.1868-7741.2025.04.05
SN - 1868-7741
VL - 30
IS - 4
SP - 156
EP - 161
PB - Erich Schmidt Verlag GmbH & Co. KG
AN - OPUS4-65098
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Welche Rolle spielen Textilien als Mikroplastik-Quelle im Abwasser?
N2 - In diesem Vortrag wird die Rolle der Waschmaschine als Eintragspfad von Mikroplastik in das Abwasser diskutiert und eine experimentelle Annäherung an das Problem beschrieben.
T2 - Wasserwirtschaftliches Kolloquium der TU Berlin
CY - Berlin, Germany
DA - 14.12.2023
KW - Mikroplastik
KW - TED-GC/MS
KW - Waschmaschine
PY - 2023
AN - OPUS4-59278
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Systemverständnis und Untersuchungsstrategien von Kunststoffeinträgen in die Umwelt – Ergebnisse des RUSEKU-Forschungsprojektes
N2 - Ziel des Vortrages ist die Vermittlung der Herausforderungen der Mikroplastik-Analytik sowie der Harmonisierung der Analytik und des Ergebnistransfers in die Normung.
T2 - Jahresabschluss-Sitzung GA "Mensch und Umwelt"
CY - Online meeting
DA - 24.11.2021
KW - Mikroplastik
KW - Mikroplastik-Analytik
PY - 2021
AN - OPUS4-53830
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hejazi, Bardia
T1 - X-ray Computed Tomography Image Compression and Denoising with AI
N2 - The ever-growing volume of data in imaging sciences stemming from advancements in imaging technology, necessitates efficient and reliable storage solutions for such large datasets. In this study, we investigated the compression of industrial X-ray computed tomography (XCT) data using deep learning and examined how these compression algorithms affect the quality of the recovered data. To determine best strategies, we investigated two different network architectures with different compression rates. The XCT data used was from a sandstone sample with a complex internal pore network. The quality of the recovered images obtained from the two different deep learning architectures with different compression rates were quantified and compared to the original input data. We showed that the most suitable architecture and compression rate can change, depending on what specific characteristics we would need to preserve for later analysis. The findings presented here can aid scientists in determining the best approaches and strategies for their data storage and analysis requirements.
T2 - BAM AI & ML Symposium
CY - Berlin, Germany
DA - 06.11.2025
KW - X-ray computed tomography
KW - Compression
KW - Deep Learning
PY - 2025
AN - OPUS4-65610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ciornii, Dmitri
A1 - Hodoroaba, Vasile-Dan
A1 - Wachtendorf, Volker
A1 - Fengler, Petra
A1 - Altmann, Korinna
T1 - Interlaboratory Comparison Reveals State of the Art in Microplastic Detection and Quantification Methods
N2 - In this study, we investigate the current accuracy of widely used microplastic (MP) detection methods through an interlaboratory comparison (ILC) involving ISO-approved techniques. The ILC was organized under the prestandardization platform of VAMAS (Versailles Project on Advanced Materials and Standards) and gathered a large number (84) of analytical laboratories across the globe. The aim of this ILC was (i) to test and to compare two thermo-analytical and three spectroscopical methods with respect to their suitability to identify and quantify microplastics in a water-soluble matrix and (ii) to test the suitability of the microplastic test materials to be used in ILCs. Two reference materials (RMs), polyethylene terephthalate (PET) and polyethylene (PE) as powders with rough size ranges between 10 and 200 μm, were used to press tablets for the ILC. The following parameters had to be assessed: polymer identity, mass fraction, particle number concentration, and particle size distribution. The reproducibility, SR, in thermo-analytical experiments ranged from 62%−117% (for PE) and 45.9%−62% (for PET). In spectroscopical experiments, the SR varied between 121% and 129% (for PE) and 64% and 70% (for PET). Tablet dissolution turned out to be a very challenging step and should be optimized. Based on the knowledge gained, development of guidance for improved tablet filtration is in progress. Further, in this study, we discuss the main sources of uncertainties that need to be considered and minimized for preparation of standardized protocols for future measurements with higher accuracy.
KW - Microplastics
KW - Interlaboratory comparison
KW - PlasticsFatE
KW - PET
KW - PE
KW - Reference materials
KW - VAMAS
KW - Thermo-analytical methods
KW - Spectroscopical methods
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630462
DO - https://doi.org/10.1021/acs.analchem.4c05403
SN - 1520-6882
VL - 97
SP - 8719
EP - 8728
PB - ACS Publications
AN - OPUS4-63046
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kochovski, Z.
A1 - Feldmann, Ines
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz
T1 - Ni- and Co-Struvites: Revealing Crystallization Mechanisms and Crystal Engineering toward Applicational Use of Transition Metal Phosphates
N2 - Industrial and agricultural waste streams (waste water, sludges, tailings, etc.) which contain high concentrations of NH4+, PO43–, and transition metals are environmentally harmful and toxic pollutants. At the same time, phosphorous and transition metals constitute highly valuable resources. Typically, separate pathways have been considered to extract hazardous transition metals or phosphate independently from each other. Investigations on the simultaneous removal of multiple components have been carried out only to a limited extent. Here, we report the synthesis routes for Ni- and Co-struvites (NH4MPO4·6H2O, M = Ni2+ and Co2+), which allow for P, ammonia, and metal co-precipitation. By evaluating different reaction parameters, the phase and stability of transition metal struvites as well as their crystal morphologies and sizes could be optimized. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P) ratios, whereas Co-struvite only forms at low M/P ratios. Detailed investigations of the precipitation process using ex situ and in situ techniques provided insights into the crystallization mechanisms/crystal engineering of these materials. M-struvites crystallize via intermediate colloidal amorphous nanophases, which subsequently aggregate and condense to final crystals after extended reaction times. However, the exact reaction kinetics of the formation of a final crystalline product varies significantly depending on the involved metal cation in the precipitation process: several seconds (Mg) to minutes (Ni) to hours (Co). The achieved level of control over the morphology and size makes precipitation of transition metal struvites a promising method for direct metal recovery and binding them in the form of valuable phosphate raw materials. Under this paradigm, the crystals can be potentially up-cycled as precursor powders for electrochemical or (electro)catalytic applications, which require transition metal phosphates.
KW - Crystallization
KW - Struvite
KW - Nickel
KW - Cobalt
KW - Phosphorous recovery
KW - Up-cycling
KW - Aqueous synthesis
PY - 2022
DO - https://doi.org/10.1021/acs.cgd.2c00284
VL - 22
IS - 7
SP - 4305
EP - 4315
PB - ACS Publications
CY - Washington D.C.
AN - OPUS4-55286
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bartczak, Dorota
A1 - Sikora, Aneta
A1 - Goenaga-Infante, Heidi
A1 - Altmann, Korinna
A1 - Drexel, Roland
A1 - Meier, Florian
A1 - Alasonati, Enrica
A1 - Lelong, Marc
A1 - Cado, Florence
A1 - Chivas-Joly, Carine
A1 - Fadda, Marta
A1 - Sacco, Alessio
A1 - Rossi, Andrea Mario
A1 - Pröfrock, Daniel
A1 - Wippermann, Dominik
A1 - Barbero, Francesco
A1 - Fenoglio, Ivana
A1 - Booth, Andy M.
A1 - Sørensen, Lisbet
A1 - Igartua, Amaia
A1 - Wouters, Charlotte
A1 - Mast, Jan
A1 - Barbaresi, Marta
A1 - Rossi, Francesca
A1 - Piergiovanni, Maurizio
A1 - Mattarozzi, Monica
A1 - Careri, Maria
A1 - Caebergs, Thierry
A1 - Piette, Anne-Sophie
A1 - Parot, Jeremie
A1 - Giovannozzi, Andrea Mario
T1 - Multiparameter characterisation of a nano-polypropylene representative test material with fractionation, light scattering, high-resolution microscopy, spectroscopy, and spectrometry methods
N2 - Reference and quality control materials with comparable physicochemical properties to nanoplastic contaminants present in environmental and food nanoplastics are currently lacking. Here we report a nanoplastic polypropylene material prepared using a top-down approach involving mechanical fragmentation of larger plastics. The material was found to be homogeneous and stable in suspension and has been characterised for average particle size, size distribution range, particle number concentration, polypropylene mass fraction and inorganic impurity Content using a wide range of analytical methods, including AF4, cFFF, PTA, (MA)DLS, MALS, SEM, AFM, TEM, STEM, EDS,Raman, ICP-MS and pyGC-MS. The material was found to have a broad size distribution, ranging from 50 nm to over 200 nm, with the average particle size value dependent on the technique used to determine it. Particle number concentration ranged from 1.7–2.4 × 1010 g−1 , according to PTA. Spectroscopy techniques confirmed that the material was polypropylene, with evidence of aging due to an increased level of oxidation. The measured mass fraction was found to depend on the marker used and ranged between 3 and 5 μg g−1 . Inorganic impurities such as Si, Al, Mg, K, Na, S, Fe, Cl and Ca were also identified at ng g−1 levels. Comparability and complementarity across the measurement methods and techniques is also discussed.
KW - Polypropylene
KW - Nanoplastics
KW - Analytics
KW - Reference material
KW - Scattering methods
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654680
DO - https://doi.org/10.1039/D5EN00917K
SN - 2051-8153
SP - 1
EP - 15
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ponader, Marco
A1 - Röder, Bettina
A1 - Paul, Martin
A1 - Weller, Michael G.
T1 - Sintered glass monoliths as supports for affinity columns
N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 min. Due to the glass material’s excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nano-filtration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run.
KW - Affinity Chromatography
KW - Affinity Extraction
KW - Affinity Separation
KW - Protein Purification
KW - Down Stream Processing
KW - Antibody Purification
KW - Diagnostic Antibodies
KW - Therapeutic Antibodies
KW - Automated Purification
KW - HPLC
KW - FPLC
KW - IgG determination
KW - Concentration step
KW - Monoclonal Antibodies
KW - Polyclonal Antibodies
KW - Human Plasma
KW - Glass Support
KW - Borosilicate Glass
KW - Monolith
KW - Sintered Material
KW - Additive Manufacturing
KW - Column holder
KW - Construction
KW - Open Science
KW - Citizen Science
KW - Protein A
KW - Regeneration
KW - High-Speed Separations
KW - Robustness
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527581
DO - https://doi.org/10.3390/separations8050056
SN - 2297-8739
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
VL - 8
IS - 5
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-52758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Ponader, Marco
A1 - Röder, Bettina
A1 - Paul, Martin
A1 - Weller, Michael G.
T1 - Sintered glass monoliths as new supports for affinity columns
N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 minute. Due to the glass material's excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nanofiltration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run.
KW - Affinity Chromatography
KW - Glass
KW - Purification
KW - Antibodies
KW - Solid support
KW - HPLC
KW - FPLC
KW - Separation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529117
DO - https://doi.org/10.20944/preprints202103.0298.v1
SN - 2310-287X
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-52911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavlidis, Sotirios
A1 - Fischer, Eric W.
A1 - Opis-Basilio, Amanda
A1 - Bera, Ayan
A1 - Guilherme Buzanich, Ana
A1 - Álvarez-Sánchez, María
A1 - Wittek, Severin
A1 - Emmerling, Franziska
A1 - Ray, Kallol
A1 - Roemelt, Michael
A1 - Abbenseth, Josh
T1 - Ambiphilic Reactivity and Switchable Methyl Transfer at a T-Shaped Bi(NNN) Complex Enabled by a Redox-Active Pincer Ligand
N2 - We report the transition-metal-like reactivity of a geometrically constrained, ambiphilic bismuth(III) trisamide. Planarization of the Bi(III) center unlocks Bi−C bond formation when reacted with mild electrophiles (alkyl iodides and triflates) accompanied by two-electron oxidation of the utilized NNN pincer nligand. The preservation of the bismuth oxidation state is confirmed by single-crystal X-ray diffraction and X-ray absorption spectroscopy and corroborated by theoretical calculations. Sequential reduction of the oxidized ligand framework alters the reactivity of a generated Bi−Me unit, enabling controlled access to methyl cation, radical, and anion equivalents. The full [Bi(Me)(NNN)]+/•/− redox series was comprehensively characterized using NMR and EPR spectroscopy as well as spectro-electrochemistry. This work represents the first example of ligand-assisted, redox-neutral C−X bond splitting at bismuth, establishing a new paradigm for synthetic bismuth chemistry.
KW - Pincer ligand
KW - XAS
KW - Redox
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654948
DO - https://doi.org/10.1021/jacs.5c18955
SN - 0002-7863
VL - 148
IS - 2
SP - 2683
EP - 2692
PB - American Chemical Society (ACS)
AN - OPUS4-65494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chakraborty, Gouri
A1 - Das, Prasenjit
A1 - Bhattacharya, Biswajit
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Thomas, Arne
T1 - Room-temperature superprotonic conductivity in COOH-functionalized multicomponent covalent organic frameworks
N2 - In solid materials, the development of hydrogen bonding (H-bonding) networks within pores is crucial for efficient proton conductance. In this study, a chemically stable carboxylic acid-functionalized, quinoline-linked 2D microporous covalent organic framework (COF) (Qy-COOH) was synthesized using the Doebner multicomponent reaction (MCR) and compared to a similar framework lacking the –COOH functionality (Qy-H), prepared via an MC Domino reaction. The proton conductivity of the –COOH-functionalized MCR-COF was significantly enhanced, reaching 10−2 S cm−1, attributed to strong H-bonding interactions between water molecules and the dangling –COOH groups within the COF pores. In contrast, the analogous Qy-H framework exhibited a much lower proton conductivity of 10−5 S cm−1, while an imine-based COF showed only 10−6 S cm−1. This work represents the first demonstration of a general strategy to achieve efficient proton conduction in a class of layered 2D –COOH-functionalized COFs, offering superprotonic conductivity without requiring additives at room temperature. The MCR-COF design approach provides a promising pathway for developing highly stable and high-performance proton-conducting materials.
KW - Multicomponebt
KW - COF
KW - Proton Conductivity
KW - Superprotonic
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653526
DO - https://doi.org/10.1039/D5SC06953J
SN - 2041-6520
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmalz, Alina
A1 - Eby, Charles Gaston
A1 - Moss, Caitlin
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Thermally Robust 1D Cu(I) Phosphonate Coordination Polymer Exhibiting Enhanced Proton Conductivity via Humidity‐Driven Pathways
N2 - The development of thermally stable solid-state proton conductors (SSPCs) is crucial for advancing energy-conversion devices such as proton-exchange membrane fuel cells (PEMFCs). In this work, we report the solvothermal synthesis and characterization of a novel, 1D Cu(I) coordination polymer, {Cu(ADP)0.5(BPY)}n (BAM-5), based on anthracenediylphosphonate (H2ADP) and 4,40 -bipyridine (BPY). Single-crystal X-ray diffraction revealed that BAM-5 crystallizes in the triclinic space group P1 and shows a 1D ladder structure connected by the H2ADP and organic BPY linkers, which is assembled into a 2D layer via O−H···O hydrogen bonding interactions between uncoordinated oxygen and the O−H of the phosphonate group. Thermogravimetric and dynamic water sorption analysis demonstrated exceptional thermal robustness of BAM-5 until 230°C and notable water affinity. Proton conductivity measurements found increasing proton conductive properties with increasing temperature and relative humidity.The latter is correlated with the material’s water uptake since the structure itself does not contain any permanent lattice water molecules. A maximum proton conductivity of 6.6 × 10−6 S cm−1 was found at 80°C and 98% RH. To the best of our knowledge, no dense, nonporous 1D coordination polymer without lattice or coordinated solvent molecules has shown comparable proton con� ductivity. The high activation energy suggests a combination of both, a Grotthuss-type proton hopping through the hydrogen� bonded framework, and a vehicular process, in which protons are carried along with absorbed water molecules.
KW - Coordination polymers
KW - Phosphonate ligand
KW - Proton conduction
KW - X-ray diffraction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651382
DO - https://doi.org/10.1002/zaac.202500187
SN - 0044-2313
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-65138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pakrashy, Sourav
A1 - Chakraborty, Souvik
A1 - Manna, Sounik
A1 - Nanda Goswami, Juli
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Mandal, Jishu
A1 - Misra, Sourav
A1 - Maiti Choudhury, Sujata
A1 - Okla, Mohammad K.
A1 - Bose, Adity
A1 - Maurya, Pawan Kumar
A1 - Majhi, Anjoy
A1 - Dolai, Malay
T1 - Inhibition of Human Colorectal Cancer by a Natural Product 7-Acetylhorminone and Interactions with BSA/HSA: Multispectral Analysis and In Silico and In Vitro Studies
N2 - We have semi-synthesized a natural product 7-acetylhorminone from crude extract of Premna obtusifolia (Indian headache tree), which is active against colorectal cancer after probation through computational screening methods as it passed through the set parameters of pharmacokinetics (most important nonblood–brain barrier permeant) and drug likeliness (e.g., Lipinski’s, Ghose’s, Veber’s rule) which most other phytoconstituents failed to pass combined with docking with EGFR protein which is highly upregulated in the colorectal carcinoma cell. The structure of 7-acetylhorminone was confirmed by single crystal X-ray diffraction studies and 1H NMR, 13C NMR, and COSY studies. To validate the theoretical studies, first, in vitro experiments were carried out against human colorectal carcinoma cell lines (HCT116) which revealed the potent cytotoxic efficacy of 7-acetylhorminone and verified preliminary investigation. Second, the drugability of 7-acetylhorminone interaction with serum albumin proteins (HSA and BSA) is evaluated both theoretically and experimentally via steady-state fluorescence spectroscopic studies, circular dichroism, isothermal titration calorimetry, and molecular docking. In summary, this study reveals the applicability of 7-acetylhorminone as a potent drug candidate or as a combinatorial drug against colorectal cancer.
KW - Molecular docking
KW - In situ synthesis
KW - ADMET
PY - 2024
DO - https://doi.org/10.1021/acsabm.4c00335
VL - 7
IS - 5
SP - 3414
EP - 3430
PB - American Chemical Society (ACS)
AN - OPUS4-61114
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Parthasarathy, Thiyagaraj
A1 - Mishra, Manish Kumar
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Ghosh, Soumyajit
T1 - Simultaneously Mechanically Flexible, Photobending, and Acidochromic Cyanostilbene Molecular Crystals
N2 - Molecular crystals that respond to multiple stimuli are gaining significant attention for their potential in smart materials like actuators and sensors. However, imparting multiple stimuli-responsive properties to a single crystal remains a major challenge. Herein, we report two cyanostilbene derivative-based crystals 1 and 2, with various responses to stimuli such as mechanical stress, light, acid vapors, etc. Both crystals 1 and 2 demonstrated mechanical flexibility and reversible acidochromism. Additionally, crystal 1 also exhibited light-induced photobending, which is ascribed to Z to E photoisomerization. Detailed structure–property correlation was established to unravel distinct mechanical responses. The development of these multitasking crystals may find applications in multitasking actuators, anticounterfeiting materials, and more.
KW - Absorption
KW - Crystals
KW - Mechanical flexiblity
KW - Photoisomerization
PY - 2025
DO - https://doi.org/10.1021/acs.cgd.4c01341
VL - 25
IS - 2
SP - 309
EP - 318
PB - American Chemical Society (ACS)
AN - OPUS4-62568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - Time-Resolved InSitu Monitoring of Mechanochemical Reactions
N2 - Mechanochemical transformations offer environmentally benign synthesis routes, whilst enhancing both the speed and selec-tivity of reactions. In this light, mechanochemistry promises to trans-form the way in which chemistry is done in both academia and indus-try but is greatly hindered by a current lack in mechanistic understand-ing. The continued development and use of time-resolved in situ(TRIS) approaches to monitor mechanochemical reactions provides a new dimension to elucidatethese fascinating transformations. We here discuss recent trends in method development that have pushed the boundaries of mechanochemical research. New features of mech-anochemical reactions obtained by TRIS techniques are subse-quently discussed, shedding light on how different TRISapproaches have beenused. Emphasis is placed on the strength of combining complementary techniques. Finally, we outline our views for the po-tential of TRIS methods in mechanochemical research, towards es-tablishing a new, environmentally benign paradigm in the chemical sciences
KW - Mechanochemistry
KW - Material synthesis
KW - Green chemistry
PY - 2022
DO - https://doi.org/10.1002/anie.202117270
SN - 1433-7851
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Production of small micro- and nanoplastic reference materials supporting harmonization and standardization
N2 - The MICROPLASTICdays at Ljubliana, Slowenia, were organized in cooperation with the PRIORITY cost action. The topic has been reference materials this time.
The talk gives an idea of the preparation of reference materials in micro- and nanoplastic topic to support standardisation and regulation. It defines the term of micro-and nanoplastics and presents different case studies and critical attributes to the production depending on the enduser needs.
T2 - MICROPLASTICdays
CY - Ljubljana, Slovenia
DA - 25.03.2025
KW - Microplastics
KW - Nanoplastics
KW - Reference materials
PY - 2025
AN - OPUS4-62801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhattacharya, Biswajit
A1 - Akhmetova, Irina
A1 - Rautenberg, Max
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis of phosphonate-based proton conducting metal organic frameworks and hydrogen-bonded metal phosphonates
N2 - Proton exchange membrane fuel cells (PEMFCs) are one of the most promising alternative green energy technologies that deliver high energy density without CO2 emissions. The proton conductivity of proton exchange membranes (PEM) contributes to the overall efficiency of a PEMFC. Materials being used as PEMs must exhibit high proton conductivity at the working conditions of the targeted PEMFC. To date, Nafion and Nafion-like polymers with acidic functionality are widely used as membrane materials due to their high proton conductivity in the range of 10-1 to 10-2 Scm-1 at higher relative humidity. However, these materials suffer from high costs, hazardous production process, and poor performance at high temperatures, limiting their versatility.
In this context, crystalline porous materials are recognized as promising proton conductors for the proton exchange membrane (PEM) in fuel cell technology, owing to their tunable framework structure. However, it is still challenging bulk synthesis for real-world applications of these materials. Herein, we present mechanochemical gram-scale synthesis of series of mixed ligand metal organic frameworks (MOFs) and metal hydrogen‐bonded organic frameworks (MHOFs) using phenylene diphosphonic acid and 1-hydroxyethylidene-1,1-diphosphonic acid with different bipyridyl type of ligands, respectively. In all cases, the existence of extensive hydrogen bonds with amphiprotic uncoordinated phosphonate hydroxyl and oxygen atoms, the frameworks exhibited high proton conductivity. The study demonstrates the potential of green mechanosynthesis for preparations of framework-based proton conducting materials in bulk scale for green energy generation.
T2 - 4th International Conference on Phosphonate Chemistry, Science and Technology, ICOPHOS-4
CY - Crete, Greece
DA - 02.10.2023
KW - Proton exchange membrane fuel cells
KW - Metal organic frameworks
KW - Proton conducting materials
PY - 2023
AN - OPUS4-58837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Exploring amorphous lewis-acidic zirconium chloro fluoride as a heterogeneous HF shuttle
N2 - Owing to a growing shortage of fluorspar, a raw material used for producing fluorinated base chemicals, fluorspar has been named among the 30 critical raw materials in the EU. 1 However, the sustainable transfer of fluorine atoms from one molecule to another using heterogeneous catalysts has not yet been reported. Herein, we present the heterogeneous catalyst zirconium chloro fluoride (ZCF) that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
T2 - Make and Measure 2023
CY - Berlin, Germany
DA - 13.09.2023
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - HF-shuttle
PY - 2023
AN - OPUS4-59616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoque, Maroof Arshadul
T1 - Mechanochemically synthesized COF for PFAS adsorption
N2 - Since the 1950s, per- and polyfluoroalkyl substances (PFAS) have been widely used in a range of consumer products, including clothing, paints, cookware and fast-food packaging. Properties such as high thermal resistance and water and oil repellency contribute to their wide usage. After decades of production, these substances have eventually found their way into our drinking water. Given the adverse effects of PFAS molecules on human health, the removal of these substances from our drinking water is a matter of urgency.1 This study employs the use of materials known as covalent organic frameworks (COFs) to adsorb PFAS molecules from an aqueous medium. COFs are crystalline, highly porous, two- or three-dimensional polymers with tunable topology and functionalities.² For the purposes of this study, a COF was synthesised using 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 1,3,5-triformylbenzene (TFB) via a mechanochemical process. Mechanochemistry represents a green synthesis method that uses mechanical energy to initiate chemical reactions, as opposed to using harmful solvents and heat.3 Adsorption tests were carried out to test the effectiveness of the material in question against PFAS. The COF was exposed to a solution of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid PFOS). Following a 13-hour period, it was observed that 90% of PFOA and 99% of PFOS had been adsorbed by the COF. Most of the adsorption appeared to have occurred within the first 10 minutes of exposure. It can therefore be concluded that the TAPB-TFB COF is a promising material for the adsorption of PFAS molecules.
T2 - Adlershofer Forschungsforum 2024
CY - Berlin, Germany
DA - 11.11.2024
KW - Covalent organic framework
KW - Mechanochemistry
KW - PFAS
KW - In situ Xray diffraction
PY - 2024
AN - OPUS4-61808
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
A1 - Karafiludis, Stephanos
A1 - Standl, Jakob
A1 - Ryll, Tom
A1 - Schwab, Alexander
A1 - Prinz, Carsten
A1 - Wolf, Jakob
A1 - Kruschwitz, Sabine
A1 - Emmerling, Franziska
A1 - Völker, Christoph
T1 - High-Entropy Metal Phosphate Synthesis: Advancements through Automation and Sequential Learning Optimization
N2 - To accelerate high-entropy metal phosphate (HEMP) discovery, we employed a Random Forest regression model within a SLAMD framework. Trained on limited initial data, the model efficiently explored the vast compositional space to predict a novel five-metal phosphate, which was then successfully synthesized and validated experimentally.
T2 - AI4 Materials Science and Testing 2025
CY - Berlin, Germany
DA - 06.11.2025
KW - Metal phosphates
KW - High-entropy
KW - Sequential learning
PY - 2025
AN - OPUS4-64686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Yusenko, Kirill
A1 - Stawski, Tomasz
A1 - Kulow, Anicó
A1 - Cakir, Cafer Tufan
A1 - Röder, Bettina
A1 - Naese, Christoph
A1 - Britzke, Ralf
A1 - Sintschuk, Michael
A1 - Emmerling, Franziska
T1 - BAMline - A real-life sample materials research beamline
N2 - With increasing demand and environmental concerns, researchers are exploring new materials that can perform as well or better than traditional materials while reducing environmental impact. The BAMline, a real-life sample materials research beamline, provides unique insights into materials’ electronic and chemical structure at different time and length scales. The beamline specializes in x-ray absorption spectroscopy, x-ray fluorescence spectroscopy, and tomography experiments. This enables real-time optimization of material properties and performance for various applications, such as energy transfer, energy storage, catalysis, and corrosion resistance. This paper gives an overview of the analytical methods and sample environments of the BAMline, which cover non-destructive testing experiments in materials science, chemistry, biology, medicine, and cultural heritage. We also present our own synthesis methods, processes, and equipment developed specifically for the BAMline, and we give examples of synthesized materials and their potential applications. Finally, this article discusses the future perspectives of the BAMline and its potential for further advances in sustainable materials research.
KW - Extended X-ray absorption fine structure
KW - Energy storage
KW - Environmental impacts
KW - Nondestructive testing techniques
KW - X-ray fluorescence spectroscopy
KW - Corrosion
KW - Near edge X-ray absorption fine structure spectroscopy
KW - X-ray absorption spectroscopy
PY - 2023
DO - https://doi.org/10.1063/5.0157194
VL - 158
IS - 24
SP - 1
EP - 22
PB - AIP Publishing
AN - OPUS4-57824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Häusler, I.
A1 - Knigge, Xenia
A1 - Hodoroaba, Vasile-Dan
A1 - Emmerling, Franziska
A1 - Reiss, P.
A1 - Resch-Genger, Ute
T1 - One-Pot Heat-Up Synthesis of ZnSe Magic-Sized Clusters Using Thiol Ligands
N2 - The synthesis of two new families of ZnSe magic-sized clusters (MSCs) is achieved using the thiol ligand 1-dodecanethiol in a simple one-pot heat-up approach. The sizes of the MSCs are controlled with the thiol ligand concentration and reaction temperature.
KW - ZnSe
KW - Magic-sized cluster
KW - Dodecanethiol
KW - Semiconductor nanocrystals
KW - One-pot synthesis
PY - 2022
DO - https://doi.org/10.1021/acs.inorgchem.2c00041
VL - 61
IS - 19
SP - 7207
EP - 7211
PB - ACS Publications
CY - Washington, DC (USA)
AN - OPUS4-54880
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Misra, Archismita
T1 - Polyoxometalate Ionic Liquids as Protective Coatings for Industrial Infrastructure and Cultural Heritage against Microbiologically Influenced Corrosion (MIC)
N2 - Corrosion of stone and metal due to acid rain and biodeterioration poses significant challenges for industrial and residential infrastructure, as well as cultural heritage, including statues and historical artefacts. A promising mitigation strategy involves thin, transparent films of polyoxometalate-based ionic liquids (POM-ILs) as chemical shields. Stone samples coated with acid-resistant, biocidal POM-ILs exhibited negligible corrosion when exposed to simulated acid rain, in stark contrast to the severe deterioration of unprotected samples. Additionally, their biocidal properties effectively prevent biofilm formation on coated surfaces. Following studies successfully explored the effectiveness of the coating against lampenflora growing in the Pommery Champagne cellar; and the long-term performance of POM-ILs under outdoor environmental conditions. So, POM-ILs have already demonstrated remarkable anticorrosion and antimicrobial properties against aerobic microorganisms and, being water-insoluble, do not leach into aquatic ecosystem. The current research project repurposes the POM-ILs, extending their application to metals, specifically targeting microbiologically influenced corrosion (MIC) in cultural heritage artefacts made of brass, carbon steel, cast iron, and bronze. This involves optimizing nanocoating adhesion to the metal surface and evaluating its protective efficacy against MIC caused by anaerobic microorganisms such as methanogenic archaea and sulfate reducing bacteria (SRB). This presentation will highlight POM-ILs as sustainable, high-performance nanocoatings for biocorrosion mitigation. It will showcase published success stories, discuss ongoing research and proof-of-concept results, and explore future prospects for these advanced materials in safeguarding metal infrastructure and artefacts across different industrial sectors as well as in the context of cultural heritage conservation.
T2 - Euro-MIC COST Action - Closing Workshop Conference
CY - Horsens, Denmark
DA - 17.09.2025
KW - Polyoxometalates
KW - Corrosion
KW - Microbiologically Influenced Corrosion
KW - Ionic Liquid
PY - 2025
AN - OPUS4-64549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adhami, Forogh
A1 - Safavi, Maliheh
A1 - Ehsani, Maryam
A1 - Ardestani, Sussan K.
A1 - Emmerling, Franziska
A1 - Simyari, Farzaneh
T1 - Synthesis, crystal structure, and cytotoxic activity of novel cyclic systems in [1,2,4]thiadiazolo[2,3-a]pyridine benzamide derivatives and their copper(ii) complexes
N2 - Three N-(pyridine-2-ylcarbamothioyl)benzamide derivatives were synthesized by the reaction of potassium thiocyanate, benzoyl chloride, and 2-amino pyridine derivatives in one pot. The obtained derivatives were oxidized using copper(II) chloride. During the oxidation, two hydrogen atoms were removed, cyclization of the derivatives occurred, and finally, three new N-(2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide derivatives were produced. Coordination of these three new derivative ligands to the copper(II) ion resulted in the formation of three new complexes: dichlorobis(N-(2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide)copper(II), dichlorobis(N-(7-methyl-2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2ylidene)benzamide)copper(II), and dichlorobis(N-(5-methyl-2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide)copper(II). All the synthesized products were characterized by IR, 1H NMR, and 13C NMR spectroscopies. Crystal structures of the obtained N-(pyridine-2-ylcarbamothioyl)benzamide derivatives, N-(2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide derivatives, and complexes were determined using X-ray single-crystal diffraction; the positions of atoms, bond lengths, bond angles, and dihedral angles were also determined. In all complexes, the coordination of two large monodentate ligands and two chloride anions to the copper(II) ion resulted in the formation of a stable planar geometry around the central ion. Three N-(pyridine-2-ylcarbamothioyl)benzamide derivatives, three N-(2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide derivatives, and three complexes were evaluated for their cytotoxicity against five human cancer cell lines (breast cancer cell line MDA-MB-231, neuroblastoma cell line SK-N-MC, prostate adenocarcinoma cell line LNCap, nasopharyngeal epidermoid carcinoma cell line KB, and liver cancer cell line HEPG-2) using an in vitro analysis. The N-(pyridine-2-ylcarbamothioyl)benzamide derivatives showed no cytotoxic activity, whereas the N-(2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide derivatives and their complexes showed significant cytotoxicity, especially against MDA-MB-231 and LNCap cell lines. The complexes demonstrated smaller IC50 values than N-(2H-[1,2,4]thiadiazolo[2,3-a]pyridine-2-ylidene)benzamide derivatives.
KW - Copper complexes
PY - 2014
DO - https://doi.org/10.1039/c3dt52905c
SN - 1477-9226
VL - 43
IS - 21
SP - 7945
EP - 7957
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Processing of calcium sulfate in brines
N2 - Calcium sulfate hemihydrate (CaSO4·0.5H2O), also known as bassanite or "plaster of Paris", serves as a precursor for the production of gypsum (dihydrate, CaSO4·2H2O), widely used in construction. Currently, ~200 MT of calcium sulfate are consumed annually.
Bassanite is obtained from gypsum through a solid-state thermal treatment in kilns at temperature ranging from 150 °C to 200 °C. We introduce a more efficient and sustainable method (T < 100 ºC) that enables the direct, rapid, and reversible conversion of gypsum to bassanite using reusable high salinity aqueous solutions (brines with c[NaCl] > 4 M).
These transformations are controlled by the properties of the solution, offering extensive opportunities for precise manipulation of crystal formation and recycling of gypsum waste.
T2 - BESSY User Meeting 2024
CY - Berlin, Germany
DA - 12.12.2024
KW - Gypsum
PY - 2024
AN - OPUS4-62095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Heymann, S.
A1 - Braun, U.
A1 - Bannick, C.-G.
A1 - Heller, C.
A1 - Fuchs, M.
A1 - Scheid, C.
A1 - Abusafia, A.
A1 - Steinmetz, H.
A1 - Ricking, M.
A1 - Kerndorff, A.
T1 - Untersuchungsverfahren von Mikroplastikgehalten im Wasser für Praxis und Wissenschaft
N2 - Zielsetzung des vom Bundesministerium für Bildung und Forschung geförderten Projektes RUSEKU war es, repräsentative Untersuchungsstrategien für die Detektion von Mikroplastik mittels TED GC/MS in wässerigen Medien zu ermitteln. Dabei wurden verschiedene Probenahmekonzepte und – verfahren für unterschiedliche Fallgestaltungen und Fragestellungen untersucht, sowie neue Filtersysteme entwickelt. Bei der Detektion der Partikel lag der Fokus auf der Anwendung und Weiterentwicklung der ThermoExtraktion/Desorption-Gaschromatographie-Massenspektrometrie (TED-GC/MS) zur Bestimmung von Mikroplastikgehalten. Anwendung fanden die Methoden bei der Beprobung von Flaschenwasser, Waschmaschinenabläufen, dem urbanen Abwassersystem der Stadt Kaiserslautern, sowie in Oberflächengewässer.
KW - Mikroplastik
KW - TED-GC/MS
KW - Mikroplastik-Analytik
KW - Probennahme
PY - 2021
VL - 14. Jahrgang
IS - 3
SP - 147
EP - 152
PB - Deutschen Vereinigung für Wasserwirtschaft, Abwasser und Abfall
CY - Hennef
AN - OPUS4-52260
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eisentraut, Paul
A1 - Altmann, Korinna
T1 - Repräsentative Mikroplastik-Detektion in Umweltproben - Weiterentwicklung der TED-GC/MS
N2 - Die große Herausforderung in der Detektion von Mikroplastik (MP)‑Partikeln (1-1000 µm) besteht darin, sie neben Millionen von natürlichen Partikeln in Umweltproben nachzuweisen. Zum Aufspüren von Senken, Eintragspfaden und für Monitoring-Kampagnen ist ein schnelles, automatisiertes Verfahren unerlässlich. Ein solches Verfahren wurde an der Bundesanstalt für Materialforschung und -prüfung (BAM) mit der ThermoExtraktion/Desorption-Gaschromatographie-Massenspektrometrie (TED-GC/MS) in den letzten Jahren entwickelt.
KW - Mikroplastik
KW - TED-GC/MS
PY - 2021
UR - https://analyticalscience.wiley.com/do/10.1002/was.0004000195
SN - 0016-3538
SP - 2
EP - 5
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54266
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Prinz, Carsten
A1 - Zimathies, Annett
A1 - Emmerling, Franziska
T1 - Experimental raw data sets associated with certified reference material BAM-P114 (titanium dioxide) for comparison of nitrogen and argon sorption, available in the universal adsorption information format (AIF)
N2 - These data sets serve as models for calculating the specific surface area (BET method) using gas sorption in accordance with ISO 9277.
The present measurements were carried out with nitrogen at 77 Kelvin and argon at 87 Kelvin.
It is recommended to use the following requirements for the molecular cross-sectional area:
Nitrogen: 0.1620 nm²
Argon: 0.1420 nm²
Expected specific surface area for nitrogen (BET): 24 to 25 m²/g
Expected specific surface area for argon (BET): 20 m²/g
Titanium dioxides certified with nitrogen sorption and additionally measured with argon for research purposes were used as sample material.
The resulting data sets are intended to serve as comparative data for own measurements and show the differences in sorption behaviour and evaluations between nitrogen and argon.
These data are stored in the universal AIF format (adsorption information format), which allows flexible use of the data.
KW - Physisorption
KW - Specific surface area
KW - AIF
KW - Argon
KW - Nitrogen
PY - 2024
DO - https://doi.org/10.5281/zenodo.13283291
PB - Zenodo
CY - Geneva
AN - OPUS4-60782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miclea, P-T
T1 - Evaluation of Toxicological Characteristics of Airborne Nano/Microplastic Particles From the Industrial Environment
N2 - Micro and nano plastic (MNPs) particles and fibres represent a global scale contamination source with hazard potential. They can be identified all around our environment, even in air, soil and water. One of the major global MNPs polluters is the textile industry, which generates plastic particles (nylon, polyester, polyurethane, polyolefin, acrylic etc.) during the manufacturing processes. The study analyses the level of particle concentration outside a company that processes textile yarns, but also from the proximity of workplaces using an online air samplers with cascade and mono filter holders for silicon (Si) and quartz filters, respectively. A laser detector was used for real- time counting of particles of six size classes (PM0.3-PM10). Silicon (Si) filters with a diameter of 9 mm and pore sizes of 10 µm and 1 µm and quartz filters with a diameter of 25 mm and a pore size of 1.2 µm were used for particle sampling. A special holder was designed and made for selective sampling (PM10 and PM1.0) on Si filters. Quartz filters were pre-calcined (8000C) before collection. Sampling parameters: airflow (GilAir Plus pump) -2 l/m3, collection time -3 hours; starting time 7.00 am (T1)/2.00 pm (T2), intermittent natural ventilation, average temperature and humidity: 23.3 0C, RH: 52.5%. The weight of particles collected (µg) on the quart filters was 4.9E-05 (T1) and 5.1E-05 (T2) and on the Si filters 3,2 E-05(T1) and 5E-06(T2). The total number of the outside particles (PM0,3-PM10) was situated between 3584,58 (T1)-15165,05(T2) and inside 9901(T1) and 12921,61(T2). The highest number of PM 10 particles inside was 72/m3 and of PM0.3 particles 71979/m3. The samples were characterized using electron microscopy and µRaman spectroscopy. All samples showed a high concentration of particles on the filter. Samples show only particles with irregular shapes. The equivalent particle diameter was for PM10: 1-5 µm and PM1<1 µm. The total Ion Chromatogram shows the presence of PET-type polymer and the TED GS-MS analysis shows that the weight of the collected particles is PET. After extracting the particles from the quartz filters, they were tested for evaluation of the cytotoxic potential of preparations on human monocyte-macrophage cell cultures and peripheral lymphocytes. In the first case, the level of cytotoxicity was at the border between non-cytotoxic and cytotoxic and in the second test the result was moderate cytotoxic.
T2 - SETAC Europe 2025
CY - Vienna, Austria
DA - 11.05.2025
KW - Microplastics
KW - TED-GC/MS
KW - Nanoplastics
KW - Raman microscopy
PY - 2025
AN - OPUS4-63378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
A1 - Wachtendorf, Volker
A1 - Trubiroha, P.
T1 - Simulationsdaten zur photooxidativen Beanspruchung an verschiedenen geografischen Freibewitterungs-Standorten
N2 - Freibewitterungen weisen grundsätzlich eine hohe Variabilität der jeweiligen Intensität der Beanspruchungsparameter auf; sie sind nicht einfach wiederholbar. Um dennoch die Ergebnisse einer Beanspruchung vergleichen zu können, ist eine aussagekräftige Charakterisierung der Freibewitterung wichtig. Traditionell werden Daten bekannter Einflussgrößen wie Globalstrahlung, Temperatur oder Feuchtewerte herangezogen. Obwohl man weiß, dass diese Größen an den exponierten Oberflächen wechselwirken und kombiniert als Mikroklima Einfluss auf Degradationsprozesse nehmen, werden schon aus Praktikabilitätsgründen diese separat als klimatische Messgrößen angegeben. Die Aussagekraft dieser Daten ist mäßig. Ziel dieses Beitrags ist es, die Aussagekraft und damit Vergleichbarkeit zu erhöhen, indem diese Messdaten als Stundendaten zu Wirkintegralen vorverarbeitet und jahresweise akkumuliert werden.
Betrachtet wird dafür der Prozess der Photooxidation, da dieser Alterungs-mechanismus bei allen Kunststoffen auftritt. Für eine einfache Modellierung wird die wirksame UV-Bestrahlung, gewichtet mit einer Arrhenius-abhängigen Ober¬flächen-temperatur (TOF), über den Beanspruchungszeitraum von hier je einem Jahr akkumuliert. Die Idee einer solchen Messgröße für photooxidative Ober¬flächen¬alterung wurde bereits vorgestellt [1]. Dort wurde ein Gerät vor¬geschlagen, mit dem dieser Wert für verschieden absorbierende Oberflächen für die Dauer einer Exposition akkumuliert wird, und ergänzend eine Abschätzung der Betauungs¬zeiten dieser Referenz-Oberflächen erfolgen könnte.
Hier soll es um eine rechnerisch generierte Zusammenstellung dieser photo¬oxidativen 1-Jahres-Alterungswerte für verschiedene Standorte gehen. Ein Temperaturfaktor erfasst dabei den Einfluss der Strahlungserwärmung auf eine weiße, graue bzw. schwarze Referenzoberflächen, spiegelt also die Kopplung von solarer Strahlung und Temperatur wider [1]. Ermittelt wird er aus Stunden¬daten der Globalstrahlung und der Lufttemperatur. Die spektrale Wirkung wird aus Sonnenhöhenständen entsprechend der geografischen Breite mit Hilfe der FastRT-Oberfläche [2] als PiT·h-Wert abgeschätzt [3].
Anhand der errechneten Jahreswerte können die Schweregrade der photo¬oxidativen Beanspruchung an den verschiedenen Standorten unmittelbar verglichen werden. Die gezeigten Simulationsdaten für ein solches „elektronisches Referenzmaterial“ für photooxidative Degradation zeigen die prinzipielle Möglichkeit einer Kartografierung solcher Daten auf.
T2 - 53. Jahrestagung der GUS
CY - Stutensee-Blankenloch, Germany
DA - 26.03.2025
KW - Polymer 3R, UV, Bestrahlung, Bewitterung
PY - 2025
SN - 978-3-9826129-2-8
VL - 53
SP - 19
EP - 28
PB - Gesellschaft für Umweltsimulation e.V.
CY - 76327 Pfinztal (Berghausen)
AN - OPUS4-62902
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
A1 - Trubiroha, Peter
A1 - Wachtendorf, Volker
T1 - Significance of new data pairs for irradiance and (surface) temperature
N2 - There is consent that UV irradiance and temperature at the place of photodegradation are the most important environmental parameters in weathering, along with humidity. This contribution shows how an improvement in the measurement data situation can improve the significance and comparability of outdoor exposures.
Photooxidative ageing is calculated using sample polymers for which the corresponding modelling data (Exposure Response Functions, ERF) is available. The mean square deviations are estimated, which result from using different spectral irradiances and different spectral sensitivities, both of the sensors and the polymers. It will be shown here how the significance of the irradiance values increases with increasing approximation of the spectral sensitivities of the sensor and polymer. Also, the mean square deviations are estimated, which result from using different activation energies and surface temperatures. A selection of different variables to describe the weathering exposure is created. The potential of either individual values or data pairs is evaluated in terms of significance or correlation to the calculated photooxidative ageing.
Recording hourly data also enables subsequent evaluations of individual test specimens, adapted to the respective colour or to determine activation energies. An accumulated value, calculated from PIT-radiometer irradiance and a suited surface temperature, can provide a comparison of different outdoor exposures over different locations or years.
Thus, a characterisation of the weathering exposure would be related to a reference spectral sensitivity (much closer to a polymer than that of a common UV radiometer), one reference activation energy, and different surface temperature scenarios with, on the one hand, graded solar absorptions (white / grey / black) and, on the other hand, different thermal couplings (coated metal / thick plastic). This results in three values each for plastic samples and coated metals (light / grey / dark).
It will never be possible to accurately predict the weathering tests for individual samples (with their specific sensitivities), but the proposed approaches can go a long way towards the comparability of outdoor weathering exposures.
T2 - 10th European Weathering Symposium EWS
CY - Graz, Austria
DA - 11.09.2024
KW - Polymer 3R
KW - Outdoor weathering
PY - 2024
SN - 978-3-9826129-1-1
SP - 121
EP - 133
PB - Stober Medien GmbH
CY - Eggenstein
AN - OPUS4-61291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Significance of new data pairs for irradiance and (surface) temperature
N2 - There is consent that UV irradiance and temperature at the place of photodegradation are the most important environmental parameters in weathering, along with humidity. This contribution shows how an improvement in the measurement data situation can improve the significance and comparability of outdoor exposures.
Photooxidative ageing is calculated using sample polymers for which the corresponding modelling data (Exposure Response Functions, ERF) is available. The mean square deviations are estimated, which result from using different spectral irradiances and different spectral sensitivities, both of the sensors and the polymers. It will be shown here how the significance of the irradiance values increases with increasing approximation of the spectral sensitivities of the sensor and polymer. Also, the mean square deviations are estimated, which result from using different activation energies and surface temperatures. A selection of different variables to describe the weathering exposure is created. The potential of either individual values or data pairs is evaluated in terms of significance or correlation to the calculated photooxidative ageing.
Recording hourly data also enables subsequent evaluations of individual test specimens, adapted to the respective colour or to determine activation energies. An accumulated value, calculated from PIT-radiometer irradiance and a suited surface temperature, can provide a comparison of different outdoor exposures over different locations or years.
Thus, a characterisation of the weathering exposure would be related to a reference spectral sensitivity (much closer to a polymer than that of a common UV radiometer), one reference activation energy, and different surface temperature scenarios with, on the one hand, graded solar absorptions (white / grey / black) and, on the other hand, different thermal couplings (coated metal / thick plastic). This results in three values each for plastic samples and coated metals (light / grey / dark).
It will never be possible to accurately predict the weathering tests for individual samples (with their specific sensitivities), but the proposed approaches can go a long way towards the comparability of outdoor weathering exposures.
T2 - 10th European Weathering Symposium EWS
CY - Graz, Austria
DA - 11.09.2024
KW - Polymer 3R
KW - Outdoor weathering
PY - 2024
AN - OPUS4-61292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - McSAS3: live demo of a Monte Carlo data analyis package for scattering studies
N2 - McSAS3 is a refactored software package for fitting large batches of (X-ray or Neutron) scattering data. It uses a Monte-Carlo acceptance-rejection algorithm to optimize model parameters - ideal for analysis of size-disperse scatterers.
The refactored code can exploit multiprocessing, traceably stores (multiple) results in the output file, and allows for re-histogramming of previous optimizations. Besides analysis of large batches, it can also be integrated in automated data processing pipelines.
The live demonstration will show how to use the software, what its limitations are, and what outcomes can look like for batches of results.
T2 - SAS Analysis Course 2023
CY - Didcot, UK
DA - 05.06.2023
KW - Scattering
KW - Software
KW - Analysis
KW - Demonstration
KW - McSAS3
KW - MOUSE
KW - Monte Carlo
KW - Automated analysis
PY - 2023
AN - OPUS4-57630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Kohlbrecher, J.
A1 - Breßler, Ingo
T1 - SASfit 0.94.12
N2 - Small-angle scattering is an increasingly common method for characterizing particle ensembles in a wide variety of sample types and for diverse areas of application. SASfit has been one of the most comprehensive and flexible curve-fitting programs for decades, with many specialized tools for various fields.
KW - Small-angle scattering
KW - SAXS
KW - SANS
KW - Scattering pattern analysis
PY - 2023
UR - https://doi.org/10.5281/zenodo.7530357
DO - https://doi.org/10.5281/zenodo.7530356
PB - Zenodo
CY - Geneva
AN - OPUS4-57913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
A1 - Wachtendorf, Volker
A1 - Trubiroha, P.
A1 - Giehl, A.
A1 - Schönlein, A.
A1 - Feil, F.
T1 - Normenvorschlag zur Bewitterung transparenter oder transluzenter Kunststoffe
N2 - Aufgrund des tieferen Eindringens der solaren Strahlung treten bei transparenten und bei transluzenten (durchscheinenden) Kunststoffen veränderte Bedingungen gegenüber opaken Proben auf. Dies kann zu speziellen Effekten und damit zu einem abweichenden Bewitterungsverhalten führen. Auch aus Mangel an geeigneten Normen werden diese Effekte häufig vernachlässigt. Deshalb initiiert der DIN-FNK auf ISO-Ebene ein entsprechendes Dokument.
Die Norm ist in der Form eines Technical Reports geplant. In einem ersten Teil sollen die Besonderheiten transparenter oder transluzenter Kunststoffe erläutert werden, um den Nutzer für mögliche Probleme zu sensibilisieren. Im zweiten Teil werden Empfehlungen für Bestrahlung oder Bewitterung herausgearbeitet. In einem dritten Teil geht es dann um Besonderheiten bei der Messung von Eigenschaftsänderungen transparenter bzw. transluzenter Kunststoffe. In informativen Anhängen sollen verschiedene Beispiele die Thematik illustrieren.
T2 - 51. Jahrestagung der GUS
CY - Stutensee-Blankenloch, Germany
DA - 29.03.2023
KW - Bewitterung
KW - Polymer 3R
KW - Bestrahlung
KW - UV
PY - 2023
SN - 978-3-9818507-8-9
SP - 39
EP - 46
PB - Gesellschaft für Umweltsimulation e.V.
CY - Pfinztal (Berghausen)
AN - OPUS4-57271
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Simulationsdaten zur photooxidativen Beanspruchung an verschiedenen geografischen Freibewitterungs-Standorten
N2 - Freibewitterungen weisen grundsätzlich eine hohe Variabilität der jeweiligen Intensität der Beanspruchungsparameter auf; sie sind nicht einfach wiederholbar. Um dennoch die Ergebnisse einer Beanspruchung vergleichen zu können, ist eine aussagekräftige Charakterisierung der Freibewitterung wichtig. Traditionell werden Daten bekannter Einflussgrößen wie Globalstrahlung, Temperatur oder Feuchtewerte herangezogen. Obwohl man weiß, dass diese Größen an den exponierten Oberflächen wechselwirken und kombiniert als Mikroklima Einfluss auf Degradationsprozesse nehmen, werden schon aus Praktikabilitätsgründen diese separat als klimatische Messgrößen angegeben. Die Aussagekraft dieser Daten ist mäßig. Ziel dieses Beitrags ist es, die Aussagekraft und damit Vergleichbarkeit zu erhöhen, indem diese Messdaten als Stundendaten zu Wirkintegralen vorverarbeitet und jahresweise akkumuliert werden.
Betrachtet wird dafür der Prozess der Photooxidation, da dieser Alterungs-mechanismus bei allen Kunststoffen auftritt. Für eine einfache Modellierung wird die wirksame UV-Bestrahlung, gewichtet mit einer Arrhenius-abhängigen Ober¬flächen-temperatur (TOF), über den Beanspruchungszeitraum von hier je einem Jahr akkumuliert. Die Idee einer solchen Messgröße für photooxidative Ober¬flächen¬alterung wurde bereits vorgestellt [1]. Dort wurde ein Gerät vor¬geschlagen, mit dem dieser Wert für verschieden absorbierende Oberflächen für die Dauer einer Exposition akkumuliert wird, und ergänzend eine Abschätzung der Betauungs¬zeiten dieser Referenz-Oberflächen erfolgen könnte.
Hier soll es um eine rechnerisch generierte Zusammenstellung dieser photo¬oxidativen 1-Jahres-Alterungswerte für verschiedene Standorte gehen. Ein Temperaturfaktor erfasst dabei den Einfluss der Strahlungserwärmung auf eine weiße, graue bzw. schwarze Referenzoberflächen, spiegelt also die Kopplung von solarer Strahlung und Temperatur wider [1]. Ermittelt wird er aus Stunden¬daten der Globalstrahlung und der Lufttemperatur. Die spektrale Wirkung wird aus Sonnenhöhenständen entsprechend der geografischen Breite mit Hilfe der FastRT-Oberfläche [2] als PiT·h-Wert abgeschätzt [3].
Anhand der errechneten Jahreswerte können die Schweregrade der photo¬oxidativen Beanspruchung an den verschiedenen Standorten unmittelbar verglichen werden. Die gezeigten Simulationsdaten für ein solches „elektronisches Referenzmaterial“ für photooxidative Degradation zeigen die prinzipielle Möglichkeit einer Kartografierung solcher Daten auf.
T2 - 53. Jahrestagung der GUS
CY - Stutensee, Germany
DA - 26.3.2025
KW - Polymer 3R
KW - UV
KW - Bestrahlung
KW - Bewitterung
PY - 2025
AN - OPUS4-62903
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Digitale Umweltsimulation am Beispiel der Photooxidation von Polymeren
N2 - Die Umweltwirkungen auf ein Material werden als Überlapp der Funktionskurven von Materialempfindlichkeit und einwirkenden Umweltparametern betrachtet. Wenn entweder die Empfindlichkeit oder die Beanspruchungen Null sind, ergibt sich auch keine Umweltwirkung und bei beidseitig Werten größer Null das jeweilige Produkt der beiden. Die Akkumulation der nicht-reversiblen Effekte über die Zeit und allen Eigenschaftsänderungen entspricht der Alterung des Materials für den jeweiligen Expositionszeitraum.
Die digitale Umweltsimulation gliedert sich hier in drei Teilaspekte. Ein erster, rein materialwissenschaftlicher Teil hat die Aufgabe, alle relevanten Materialempfindlichkeiten experimentell zu quantifizieren. Ein zweiter – unter Umständen numerischer Teil – hat die Aufgabe, das Bauteil und seine Einbaulage zu digitalisieren und aus den makroskopischen Umgebungsbedingungen die relevanten mikroklimatischen Umweltparameter für alle Oberflächen- oder Volumenelemente zu bestimmen. In einem dritten Teil werden die Einwirkungen über den betrachteten Zeitraum berechnet und kumuliert. Dieses Konzept, das auf den so genannten Expositions-Reaktions-Funktionen (ERF) basiert, wird an Beispielen der Photoxidation erläutert. Dieses Vorgehen wurde schon beim ViPQuali-Projekt als Numerische Umweltsimulation umgesetzt.
Überprüft werden muss das Modell unbedingt an einer realitätsnahen Validierungsbeanspruchung. Hier werden die ermittelten ERFs mit über den kompletten Beanspruchungszeitraum geloggten Umweltparametern gekoppelt, um die berechnete mit der experimentell erfahrenen Alterungswirkung zu vergleichen. Nur so kann sichergestellt sein, dass alle für die Anwendungsumgebung relevanten Materialempfindlichkeiten einbezogen wurden.
T2 - 52. Jahrestagung der GUS
CY - Blankenloch, Germany
DA - 26.03.2024
KW - Polymer 3R
KW - UV
KW - Bestrahlung
KW - Bewitterung
PY - 2024
AN - OPUS4-59831
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
T1 - Gedanken, Tipps & Tricks zu künstlichen Bewitterungsprüfungen
N2 - Die Fragestellung kann nur exemplarisch dargestellt werden, aber ist
hoffentlich auch für langjährige Praktiker in den ausgewählten
Punkten interessant. Es sollen für folgende Bereiche Beispiele gegeben
werden: Probenvorbereitung, Testvorbereitung, Testdurchführung
und Auswertung.
T2 - 53. Jahrestagung der GUS 2025; Umwelteinflüsse erfassen, simulieren, bewerten.
CY - Stutensee, Germany
DA - 26.03.2025
KW - Künstliche Bewitterung
KW - Umweltsimulation
KW - Wechseltemperaturen
KW - Prüfung
KW - UV
KW - Feuchte
KW - Beregnung
PY - 2025
AN - OPUS4-62862
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
T1 - Combined impact of UV radiation and nitric acid (HNO3) on HDPE jerrycans – comparison of outdoor and lab test
N2 - A damaging action of HNO3-55% only occurs in combination with its decomposition into nitrous gases, which can be caused by UV radiation. In a laboratory test, transparent HDPE jerrycans have been exposed to both UV radiation and 55 wt-% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The respective damages are compared with FTIR spectroscopy in ATR and HT-gel permeation chromatography (GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. The gradual increase in oxidative damage shows the good reproducibility of the lab exposure. The decomposition of nitric acid into nitrous gases by UV radiation – as well as the jerrycan oxidation – is also observed at lower HNO3 concentration (28 wt- %). Similar results are obtained after outdoor tests. Again, the damage occurs only after combined exposure, in contrast to the exposures to UV only and to HNO3 only, which were conducted in parallel. Outdoor exposures are most readily accepted as they represent possible end-use conditions. However, the reproducibility of these exposures is poor due to the large temporal variations in weather. There are also several safety risks, which is why the number of replicates remains limited. Since the outdoor and lab exposure tests show the same qualitative results, it is appropriate to conduct systematic studies in the laboratory. After 6 days of lab exposure, the oxidation damage is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. It should be noted that this amount can also occur in two sunny weeks.
T2 - 24th iapri World Packaging Conference
CY - Valencia, Spain
DA - 17.06.2024
KW - UV exposure
KW - Nitric acid
KW - Polyethylene
KW - Oxidation
PY - 2024
AN - OPUS4-60416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - What can thermoanalytical methods do for you ?
N2 - This presentation summarizes outcomes of the CUSP projects POLYRISK and PlasticsFatE according to thermoanalytical methods.It highlights the importants of analytical methods to measure physical and chemical properties of the test materials. These informations are neccessary for interpretation of the toxicological test results.
T2 - CUSP conference
CY - Utrecht, Netherlands
DA - 14.09.2023
KW - Microplastics
KW - TED-GC/MS
KW - CUSP
KW - Polymer 3R
KW - Thermoanalytical methods
PY - 2023
AN - OPUS4-58312
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
A1 - Wägner, Yannick
A1 - Geburtig, Anja
T1 - Gedanken, Tipps & Tricks zu künstlichen Bewitterungsprüfungen
N2 - Die Fragestellung kann nur exemplarisch dargestellt werden, aber ist hoffentlich auch für langjährige Praktiker in den ausgewählten Punkten interessant. Es sollen für folgende Bereiche Beispiele gegeben werden: Probenvorbereitung, Testvorbereitung, Testdurchführung und Auswertung.
T2 - 53. Jahrestagung der GUS 2025
CY - Stutensee-Blankenloch bei Karlsruhe, Germany
DA - 26.03.2025
KW - Wechseltemperaturen
KW - Künstliche Bewitterung
KW - Prüfung
KW - UV
KW - Feuchte
KW - Beregnung
PY - 2025
SN - 978-3-9826129-2-8
VL - 53
SP - 253
EP - 257
PB - Gesellschaft für Umweltsimulation e.V.
CY - 76327 Pfinztal (Berghausen)
AN - OPUS4-62861
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
A1 - Geburtig, Anja
T1 - Digitale Umweltsimulation am Beispiel der Photooxidation von Polymeren
N2 - Die Umweltwirkungen auf ein Material werden als Überlapp der Funktionskurven von Materialempfindlichkeit und einwirkenden Umweltparametern betrachtet. Wenn entweder die Empfindlichkeit oder die Beanspruchungen Null sind, ergibt sich auch keine Umweltwirkung und bei beidseitig Werten größer Null das jeweilige Produkt der beiden. Die Akkumulation der nicht-reversiblen Effekte über die Zeit und allen Eigenschaftsänderungen entspricht der Alterung des Materials für den jeweiligen Expositionszeitraum.
Die digitale Umweltsimulation gliedert sich hier in drei Teilaspekte. Ein erster, rein materialwissenschaftlicher Teil hat die Aufgabe, alle relevanten Materialempfindlichkeiten experimentell zu quantifizieren. Ein zweiter – unter Umständen numerischer Teil – hat die Aufgabe, das Bauteil und seine Einbaulage zu digitalisieren und aus den makroskopischen Umgebungsbedingungen die relevanten mikroklimatischen Umweltparameter für alle Oberflächen- oder Volumenelemente zu bestimmen. In einem dritten Teil werden die Einwirkungen über den betrachteten Zeitraum berechnet und kumuliert. Dieses Konzept, das auf den so genannten Expositions-Reaktions-Funktionen (ERF) basiert, wird an Beispielen der Photoxidation erläutert. Dieses Vorgehen wurde schon beim ViPQuali-Projekt als Numerische Umweltsimulation umgesetzt.
Überprüft werden muss das Modell unbedingt an einer realitätsnahen Validierungsbeanspruchung. Hier werden die ermittelten ERFs mit über den kompletten Beanspruchungszeitraum geloggten Umweltparametern gekoppelt, um die berechnete mit der experimentell erfahrenen Alterungswirkung zu vergleichen. Nur so kann sichergestellt sein, dass alle für die Anwendungsumgebung relevanten Materialempfindlichkeiten einbezogen wurden.
T2 - 52. Jahrestagung der GUS
CY - Stutensee-Blankenloch, Germany
DA - 26.03.2024
KW - UV
KW - Polymer 3R
KW - Bewitterung
KW - Bestrahlung
PY - 2024
SN - 978-3-9826129-0-4
SP - 31
EP - 40
PB - Gesellschaft für Umweltsimulation e.V.
CY - Pfinztal (Berghausen)
AN - OPUS4-59830
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meurer, Maren
T1 - Is olypropylene relevant for microplastic analytics?
N2 - Nowadays, in every terrestrial and aquatic ecosystem, even in the remotest areas, small residues of plastics, the so called microplastic (MP) can be found. MPs are particles with a size of 1-1000 µm (ISO/TR 21960:2020), mainly containing synthetic polymers like polyethylene (PE), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET). Even styrene-butadiene rubber (SBR) as an indication for tire wear is included due to similar particle formation. To understand the MPs consequences to the environment, it is of high priority to capture its extent of contamination. It is surprising that in the analysis of polymer masses in environmental samples, PE, PS and SBR are often detected, but only small amounts of PP, although this is the second most commonly produced standard plastic and many MP particles originate from carelessly disposed packaging materials.
This presentation provides hypotheses about the reasons of rare PP identification and mass quantification in environmental samples. Different investigations of pristine PP and representative environmental samples, including the pre-treatment by Accelerated Solvent Extraction (ASE) or with density separation followed by the thermal extraction / desorption gas chromatography-mass spectrometry (TED-GC/MS) are presented. The results are discussed according to the material properties and a possible degradation mechanism under different weathering conditions which indicate less stability under relevant storage conditions.
T2 - Society of Environmental Toxicology and Chemistry
CY - Dublin, Ireland
DA - 30.04.2023
KW - Sample preparation
KW - Polypropylene
KW - Microplastic
KW - Degradation
PY - 2023
AN - OPUS4-57474
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radunz, Sebastian
A1 - Kraus, Werner
A1 - Bischoff, F. A.
A1 - Emmerling, Franziska
A1 - Resch-Genger, Ute
A1 - Tschiche, Harald
T1 - Temperature- and Structure-Dependent Optical Properties and Photophysics of BODIPY Dyes
N2 - We report on the temperature- and structural-dependent optical properties and photophysics of a set of boron dipyrromethene (BODIPY) dyes with different substitution patterns of their meso-aryl subunit. Single-crystal Xray diffraction analysis of the compounds enabled a classification of the dyes into a sterically hindered and a unhindered group. The steric hindrance refers to a blocked rotational motion of the aryl subunit around the bond connecting this moiety to the meso-position of the BODIPY core. The energy barriers related to this rotation were simulated by DFT calculations. As follows from the relatively low rotational barrier calculated to about 17 kcal/mol, a free rotation is only possible for sterically unhindered compounds. Rotational barriers of more than 40 kcal/mol determined for the sterically hindered compounds suggest an effective freezing of the rotational motion in These molecules. With the aid of temperature-dependent spectroscopic measurements, we could show that the ability to rotate directly affects the optical properties of our set of BODIPY dyes. This accounts for the strong temperature dependence of the fluorescence of the sterically unhindered compounds which show a drastic decrease in fluorescence quantum yield and a significant shortening in fluorescence lifetime upon heating. The optical properties of the sterically hindered compounds, however, are barely affected by temperature. Our results suggest a nonradiative deactivation of the first excited singlet state of the sterically unhindered compounds caused by a conical intersection of the potential energy surfaces of the Ground and first excited state which is accessible by rotation of the meso-subunit. This is in good agreement with previously reported deactivation mechanisms. In addition, our results suggest the presence of a second nonradiative depopulation pathway of the first excited singlet state which is particularly relevant for the sterically hindered compounds.
KW - Fluorescence
KW - Sensor
KW - Switch
KW - pH
KW - BODIPY
KW - Dye
KW - Probe
KW - Synthesis
KW - Photophysics
KW - Mechanism
PY - 2020
DO - https://doi.org/10.1021/acs.jpca.9b11859
SN - 1089-5639
VL - 124
IS - 9
SP - 1787
EP - 1797
PB - American Chemical Society
AN - OPUS4-50639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Olivera, Paulo
A1 - Michalchuk, Adam
A1 - Marquardt, Julien
A1 - Feiler, Torvid
A1 - Prinz, Carsten
A1 - Torresi, R.
A1 - Camargo, P.
A1 - Emmerling, Franziska
T1 - Investigating the role of reducing agents on mechanosynthesis of Au nanoparticles
N2 - Control over the bottom up synthesis of metal nanoparticles (NP) depends on many experimental factors, including the choice of stabilising and reducing agents. By selectively manipulating these species, it is possible to control NP characteristics through solution-phase synthesis strategies. It is not known, however, whether NPs produced from mechanochemical syntheses are governed by the same rules. Using the Au NPs mechanosynthesis as a model system, we investigate how a series of common reducing agents affect both the reduction kinetics and size of Au NPs. It is shown that the relative effects of reducing agents on mechanochemical NP synthesis differ significantly from their role in analogous solution-phase reactions. Hence, strategies developed for control over NP growth in solution are not directly transferrable to environmentally benign mechanochemical approaches. This work demonstrates a clear need for dedicated, systematic studies on NP mechanosynthesis.
KW - Mechanochemistry
KW - Metal nanoparicels
PY - 2020
DO - https://doi.org/10.1039/d0ce00826e
VL - 22
IS - 38
SP - 6261
EP - 6267
PB - Royal Society of Chemistry
AN - OPUS4-51757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - May, Anastasia
T1 - Thermomechanochemical Synthesis of Pimelic Acid Cocrystals
N2 - Milling temperature is a critical factor in mechanochemistry, affecting the kinetics and outcomes of reactions. In the context of cocrystallization, the influence of milling temperature on the process has been investigated for cocrystal systems pyrazinamide:pimelic acid (PZA:PA) and 4,4'-bipyridine:pimelic acid (BPY:PA). By means of temperature-controlled milling, stabilization of metastable polymorph of PZA:PA was achieved, thereby decelerating the aging process of the polymorph. This was accomplished through controlled heated milling of PZA and PA. Furthermore, we have successfully synthesized all three BPY:PA polymorphs by mechanochemistry involving controlled cooled and heated milling. In previous studies, only the most stable polymorph was obtained by mechanochemistry.
T2 - 10th European Crystallography School
CY - Ohrid, North Macedonia
DA - 23.06.2025
KW - Mechanochemistry
KW - Cocrystal
PY - 2025
AN - OPUS4-63797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, D.
A1 - Ahmad, S.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Stress and light sensitive dual-mechanical property of acylhydrazone crystal
N2 - Mechanically dual-responsive molecular crystals have gained ubstantial interest among researchers due to their significant applications in various fields. However, incorporation of disparate mechanical responses in the same crystalline material is still a challenging issue and is continuously being explored. Here, we report long acicular crystals derived from 4-bromobenzhydrazide and 9-anthraldehyde exhibit both stressinduced mechanical bending and blue-light induced photomechanical bending. Furthermore, the crystals show thermal back isomerization upon gradual heating. These two distinct mechanical responses in the crystalline phase have been studied and their structure–property correlation have been established.
KW - Light sensitive crystal
KW - Mechanical flexibility
KW - Organic crystal
PY - 2023
DO - https://doi.org/10.1039/d3ce00296a
VL - 25
IS - 21
SP - 3237
EP - 3244
PB - Royal Society of Chemisty (RSC)
CY - London/Cambridge
AN - OPUS4-57593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tuma, Dirk
A1 - Mady, A. H.
A1 - Baynosa, M. L.
A1 - Saad, M.
A1 - Dhakal, G.
A1 - Kim, W. K.
A1 - Shim, Jae-Jin
T1 - Morphology-engineered hollow NiTiO₃/C–Ag/Ag₃PO₄ S-scheme heterojunction photocatalyst: mechanistic insights into sunlight-driven tetracycline degradation
N2 - Tetracycline (TCH), a widely used antibiotic, persists in aquatic and terrestrial environments, posing ecological risks and accelerating antibiotic resistance. To address this, we report a hollow-structured NiTiO₃/C–Ag/Ag₃PO₄ (NT/C–AAP)
photocatalyst—the first hollow-type nickel titanate—synthesized via a self-template solvothermal route followed by photodeposition. The catalyst integrates key design strategies—hollow architecture, oxygen vacancies, carbon coating, and an S-scheme heterojunction—to optimize photocatalytic performance. The hollow structure enhances light harvesting via internal scattering, oxygen vacancies facilitate O2 adsorption and superoxide (O₂•⁻) generation, and the S-scheme heterojunction effectively suppresses electron–hole recombination while preserving strong redox potential. NT/C–AAP achieved 96% TCH degradation within 1 h and 82% mineralization in 3 h under solar light, far exceeding core–shell (18%) and aggregated (47%) NiTiO₃-based catalysts. Complete removal was realized within 40 min under 400 W visible light. The catalyst maintained 96% activity after five cycles, confirming excellent durability. Compared with previously reported NiTiO₃ photocatalysts, NT/C–AAP delivered a 50–400% performance enhancement arising from its engineered hollow structure and improved electronic properties. Mechanistic studies identified O₂•⁻ and •OH radicals as dominant species, validating the role of morphology and interface engineering in directing charge separation and redox activity. Additionally, a catalyst performance index was proposed to facilitate comparison across diverse conditions. Overall, this work introduces a novel, durable photocatalyst that links structural design to functional performance and demonstrates strong potential for practical environmental remediation.
KW - Heterojunction photocatalyst
KW - Photodegradation
KW - Tetracycline
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655946
DO - https://doi.org/10.1007/s42114-025-01600-x
SN - 2522-0128
VL - 9
IS - 2
SP - 1
EP - 19
PB - Springer Nature
CY - London
AN - OPUS4-65594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwibbert, Karin
A1 - de Eulate Pérez, Elisa García
A1 - Wen, Keqing
A1 - Voss, Heike
A1 - Thiele, Dorothea
A1 - Richter, Anja M.
A1 - Bonse, Jörn
T1 - Escherichia coli repellence via laser-induced periodic surface structures (LIPSS) on titanium: Critical role of biofilm-associated gene expression
N2 - The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Titanium
KW - Biofilm
KW - Antifouling
KW - Gene expression
KW - Fluorescence microscopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655572
DO - https://doi.org/10.1016/j.apsusc.2026.166363
SN - 0169-4332
VL - 730
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Villajos, José Antonio
A1 - Dautain, O.
A1 - Maiwald, Michael
A1 - Emmerling, Franziska
T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy
N2 - We report the scale-up of a batch solid synthesis of zeolitic imidazolate framework-8 (ZIF-8) for reactive extrusion. The crystalline product forms in the extruder directly under the mixture of solid 2-methylimidazole and basic zinc carbonate in the presence of a catalytic amount of liquid. The process parameters such as temperature, liquid type, feeding rate, and linker excess were optimized using the setup specifically designed for in situ Raman spectroscopy. Highly crystalline ZIF-8 with a Brunauer–Emmett–Teller (BET) surface area of 1816 m2 g–1 was quantitatively prepared at mild temperature using a catalytic amount of ethanol and a small excess of the linker. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of metal–organic framework (MOF) syntheses in view of their large-scale production.
KW - Mechanochemistry
KW - In situ Raman
KW - Large-scale processing
KW - Metal−organic frameworks
KW - Twin-screw extrusion (TSE)
PY - 2023
DO - https://doi.org/10.1021/acssuschemeng.2c07509
SN - 2168-0485
VL - 11
IS - 13
SP - 5175
EP - 5183
PB - ACS Publications
AN - OPUS4-57366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Božičević, Lucija
A1 - Altmann, Korinna
A1 - Hildebrandt, Jana
A1 - Knigge, Xenia
A1 - Vrček, Valerije
A1 - Peranić, Nikolina
A1 - Kalcec, Nikolina
A1 - Vinkovic Vrcek, Ivana
T1 - Estrogenic activity of plastic nanoparticles mixture under in vitro settings
N2 - The plastic value chain, central part of modern living, caused environmental pollution and bioaccumulation of plastic nanoparticles (PNPs). Their ubiquitous presence in different environmental and biological compartments has become a serious threat to human health and ecosystems. Frequently used plastic materials such as polypropylene (PP), polystyrene (PS) and polyethylene (PE) have been detected in the form of PNPs in the food chain, soil, water and air, as well as in human feces and blood. In this study, we aimed to provide novel insights in endocrine disrupting properties of PNPs using in vitro estrogen receptor (ER) transactivation assay. The effects of PP-NPs, PE-NPs and PS-NPs and their mixture on T47D-KBluc cell line stably transfected with luciferase as reporter enzyme was evaluated by means of cytotoxicity, cellular uptake and ER activation. Tested dose range for PNPs was 0.001 – 10 mg/L. Both cellular uptake and cytotoxicity for all PNPs was found to be dose-dependent. Only the highest dose of PP-NPs and PE-NPs induced apoptosis and cell death, while PS-NPs were not cytotoxic in tested dose range. For tested concentrations, PP-NPs and PE-NPs showed significant agonistic activity on ER, while PS-NPs cannot be considered ER active. When, applied as mixture, PNP demonstrated additive toxicity effects compared to the effect of each individual PNPs. Additivity was also observed for ER agonistic effect of PNPs mixture according to the benchmark dose-addition modelling approach. This study provides missing science-based evidence on endocrine disrupting effects of PE-NPs, PP-NPs, PS-NPs and their mixtures and highlights the importance of considering unintentional, aggregate and combined exposure to different PNPs in risk management.
KW - Risk assessment
KW - Nanoplastics
KW - Estrogenic activity of plastic nanoparticles
PY - 2024
DO - https://doi.org/10.1039/D3EN00883E
SN - 2051-8153
VL - 11
IS - 5
SP - 2112
EP - 2126
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmitt, M.
A1 - Altmann, Korinna
A1 - Fengler, Petra
A1 - Gehde, M.
T1 - Air-based polyethylene fragmentation with high yield to form microplastic particles as reference material candidates
N2 - Microplastic particles with sizes between 1 to 1000 μm are widely distributed worldwide. Origin, transport pathways and fate are poorly known, as sampling, sample preparation and detection methods are major challenges. In addition, reference materials that mimic environmental particles are lacking. Most challenging is the yield of MP particle production and the need for resource-intensive grinding with liquid nitrogen. In this paper, a machine is designed to produce aged microplastic particles as reference material candidates with high yield. The machine is based on ultraviolet aging of a thin foil and mechanical fragmentation using clean air. An example of aging and fragmentation of high density polyethylene with additional physical and chemical characterization of shape, size, aging state by carbonyl index and density is presented.
KW - Microplastics
KW - Degradation of polyethylene
KW - Air fragmentation
KW - Microplastics reference material
PY - 2023
DO - https://doi.org/10.1002/appl.202200121
SP - 1
EP - 18
PB - Wiley online library
AN - OPUS4-57203
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weber, Simone
T1 - Influence of the pH Value to the Degradation of Ester-Based Thermoplastic Polyurethanes
N2 - Microplastics are solid polymeric particles with a size of 1-1000 μm (ISO/TR21960:2020), which can be emitted from mismanaged waste into the environment, where microplastic is now ubiquitous. What happens to the microplastics after ending up in the environment, which risks entail and what effects it has are not sufficiently clarified up to now. The most certain issue is that the plastic particles in the environment are exposed to natural ageing, are fragmenting and degrading, such that the potential risk to ecosystems and humans is increasing due to the formation of smaller and smaller particles, potentially even including nanoplastics, if these are ingested before their further degradation. Therefore, and in view of a possible registration of polymers under REACH in the future, it is necessary to investigate the degradation of thermoplastic polyurethanes (TPU) regarding hydrolysis stability to evaluate possible risks and effects to the environment.
In the present studies, one thermoplastic polyurethane – with and without hydrolysis stabilizer – is exposed to different pH buffers at 50°C for 14 days to investigate hydrolysis depending to different pH values (acid, alkali and neutral) based on OECD guideline TG111. The hydrolysis behavior of the TPUs is characterized by surface sensitive techniques and on bulk properties. First degradation effects can be detected by SEC. Hydrolysis, especially under acidic and basic conditions, leads to chain scissions to lower molecular masses. Furthermore, the degradation products which indicate the structure of the bulk material were detected by thermo-analytical methods like TGA-FTIR for the small degradation products and the thermo extraction/desorption-gaschromatography/mass spectrometry (TED-GC/MS) for bigger degradation products. Acidic and basic hydrolysis shows the same degradation behavior which is caused by a preferred scission of the ester and urethane functionalities. Surface-sensitive techniques such as XPS demonstrate less carboxylic acid formation at acidic than at alkaline pH value in the TPU without stabilator, where as the TPU with stabilator ages to the same extent in both pH ranges. Altogether, the hydrolysis of TPUs – independently of added stabilizer or not – in acid and alkali environment is accelerated compared to the neutral hydrolysis.
T2 - SETAC
CY - Dubin, Ireland
DA - 30.04.2023
KW - Degradation
KW - Thermoplastic Polyurethane
KW - Microplastic
KW - Polymer Hydrolysis
KW - Polymer 3R
KW - REACH
PY - 2023
AN - OPUS4-58906
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wiesner, Yosri
T1 - Erfassung von Degradationsprodukten und Additiven sowie temperaturspezifische Pyrolyseprodukte mittels TED-GC/MS
N2 - Im der Präsentation werden, neben der Möglichkeit der Mikroplastikquantifizierung, auf weitere Anwendungsfelder der Methode TED-GC/MS eigegangen. Dies beinhaltet die Erfassung von Degradationsprodukten UV/O2 geschädigter Polymere und die Detektion von Additiven. Die Optimierung der Methode betreffend Messzeit und materialspezifischer Messanforderung sind ebenfalls Gegenstand.
T2 - Kolloquium Massenspektrometrie von Polymeren
CY - Berlin, Germany
DA - 09.05.2023
KW - TED-GC/MS
KW - Polymere
KW - Degradation
KW - Additive
PY - 2023
AN - OPUS4-57480
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Moss, Caitlin
T1 - Mechanochemistry as a Green Synthetic Route
N2 - Mechanochemistry has emerged as a transformative approach in sustainable chemistry, offering a solvent-free and energy-efficient pathway for chemical synthesis. By utilizing mechanical force—typically through ball milling, grinding, or other shear-driven methods, reactions can proceed without the extensive use of harmful solvents, reducing waste and environmental impact. This poster explores the principles, methodologies, and applications of mechanochemistry in developing greener synthetic routes, with a focus on pharmaceutical and materials science applications. Key advantages, including reduced reaction times, enhanced selectivity, and improved atom economy, will be highlighted alongside challenges such as scalability. By presenting mechanochemistry as a frontier technology at the intersection of chemistry, materials science, and environmental stewardship, this work invites dialogue among students and academics about its future in sustainable innovation.
T2 - Furture WINS 2024
CY - Berlin, Germany
DA - 21.11.2024
KW - Mechanochemistry
KW - Green chemistry
PY - 2024
AN - OPUS4-62123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Synthesis of zirconiumfluorides using a sol-gel/postfluorination approach and their application in C-F bond activation
N2 - ZrF4 species have shown to exhibit hard Lewis acidity in homogeneous systems. In order to study solid state Lewis acidic ZrF4 a sol-gel synthesis was adapted following previous approaches for AlF3 and a necessary post fluorination is being optimised to obtain a Lewis acidic heterogeneous catalyst for C-F bond activation. The influence of different Zr precursors was also studied while the local coordination sphere of a active species was found to be similar to β-ZrF4 using EXAFS of the Zr K-edge.
T2 - RSC Twitter Poster Conference 2023
CY - Online meeting
DA - 28.02.2023
KW - ZrF4
KW - Heterogeneous catalysis
PY - 2023
AN - OPUS4-57227
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nag, Sayak
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Ghosh, Soumyajit
T1 - Stress and Light-Induced Dual Mechanical Properties of Two 1,3-Dicyanostilbene Derivative Crystals
N2 - Dynamic molecular crystals with multistimuli responses hold immense potential for applications as actuators and smart materials. Here, we report two new 1,3-dicyanostilbene derivative crystals (crystals 1 and 2), which exhibit dual mechanical responses. Both crystals 1 and 2 demonstrate stress-induced mechanical flexibility and light-induced photomechanical bending upon exposure to a 375 nm UV LED. These two distinct mechanical responses are associated with different underlying phenomena and are independent of each other. Mechanical flexibility is attributed to the absence of slip planes and a criss-cross packing arrangement in an isotropic structure, while photomechanical bending is ascribed to the formation of a heterogeneous phase distribution due to Z → E photoisomerization. However, they show thermal reversibility, pointing toward a reversible E → Z back isomerization. This study demonstrates that single molecular crystals combining mechanical flexibility and photomechanical bending can be designed and fabricated for developing multistimuli responsive actuators.
KW - Photoisomerization
KW - Crystal structure
KW - Crystals
KW - Flexibility
KW - Molecules
PY - 2025
DO - https://doi.org/10.1021/acs.cgd.5c00097
SN - 1528-7483
SP - 1
EP - 11
PB - American Chemical Society (ACS)
AN - OPUS4-63267
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cirkovic Velickovic, T.
A1 - Altmann, Korinna
A1 - Dailey, L
T1 - CUSP Conference WG1 & WG3: MATERIALS AND METHODS
N2 - This talk is a presentation about the main results of the CUSP cluster on micro- and nanoplastics human health that work from 2021 to 2025 in Horizon Europe programme according to the WG1 and 3. These groups combined the analytics and the materials with interlaboratory comparisons (ILC). The talk reflects the need of realistic test materials with defined properties for micro- and nanoplastic research. Some were developed are now available. The talk also highlights the need for harmonisation and the results of different ILCs that were performed.
T2 - CUSP conference
CY - Brussels, Belgium
DA - 25.02.2025
KW - Microplastics
KW - Reference materials
KW - Interlaboratory comparison (ILC)
PY - 2025
AN - OPUS4-62703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casali, Lucia
T1 - Kinetics of the mechanically induced ibuprofen-nicotinamide co-crystal formation by in-situ X-ray diffraction
N2 - Mechanochemistry offers sustainable synthesis for pharmaceuticals, though scaling remains challenging. By combining time-resolved in situ X-ray diffraction with kinetic modeling on the mechanosynthesis of the co-crystal ibuprofen-nicotinamide, we identified the reaction-driving factors. This deeper insight opens the way for a scale-up of mechanochemistry in the pharmaceutical industry.
T2 - CGOM15 (15th International Workshop on Crystal Growth of Organic Materials)
CY - Phuket, Thailand
DA - 23.07.2024
KW - Mechanochemistry
KW - Kinetics
KW - In-situ monitoring
PY - 2024
AN - OPUS4-61756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casali, Lucia
T1 - Kinetics of the mechanically induced ibuprofen-nicotinamide co-crystal formation by in-situ X-ray diffraction
N2 - Mechanochemistry offers sustainable synthesis for pharmaceuticals, though scaling remains challenging. By combining time-resolved in situ X-ray diffraction with kinetic modeling on the mechanosynthesis of the co-crystal ibuprofen-nicotinamide, we identified the reaction-driving factors. This deeper insight opens the way for a scale-up of mechanochemistry in the pharmaceutical industry.
T2 - BESSY User meeting
CY - Berlin, Germany
DA - 11.12.2024
KW - Mechanochemistry
KW - Kinetics
KW - In-situ monitoring
PY - 2024
AN - OPUS4-62193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wegner, Karl David
T1 - One-Pot Heat-Up Synthesis of ZnSe Magic-Sized Clusters Using Thiol Ligands
N2 - The unique optoelectronic properties of semiconductor nanocrystals, also termed quantum dots (QDs), have led to many advances in optoelectronic devices, bioimaging, and biosensing. This strong potential in a wide range of applications sparked the interest for a better understanding of the QD formation mechanisms. Recent studies have shown that atomically defined, zero-dimensional magic-size clusters (MSCs) play a crucial role during the nucleation and growth of QDs. Thereby MSCs consist of discrete numbers of ions leading to narrow size distributions and thus narrow absorption peaks, which evolve in discrete steps from one stable size to the next. The formation of MSCs was found in the synthesis of II-VI and III-V QDs but only limited synthesis approaches are available for the synthesis of MSCs in single-ensemble form without coexistence of other-size QDs. These MSCs can further self-assemble into two- and three-dimensional hybrid structures using organic ligands like diamines, leading to enhanced photoluminescence properties and catalytic activities.
In this contribution, we present a synthesis strategy for the preparation of single-sized ZnSe MSCs. With a band gap of 2.7 eV and being an earth-abundant material, ZnSe QDs are interesting for light-emitting devices, blue-green lasers, photocatalysis, and fluorescence probes. In contrast to other studies, our approach is based on a one-pot heat-up synthesis and uses less toxic and dangerous zinc precursors (e.g. zinc stearate). Knowing that thiol-based ligands can alter the formation process of ZnSe QDs, we investigated the influence of 1-dodecanethiol on the ZnSe MSC formation using absorption spectroscopy, TEM, XPS, and XRD. By variation of the thiol ligand concentration and reaction temperature, we were able to synthesize two new ZnSe MSC sizes, the largest so far, by using easy-to-handle precursors.
T2 - NANOHYBRID - Hamburg Conference on Complex Nanostructures
CY - Hamburg, Germany
DA - 04.10.2022
KW - ZnSe
KW - Magic-sized cluster
KW - Nanoparticle
KW - Synthesis
KW - Nanomaterial
PY - 2022
AN - OPUS4-56193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - AfLS3
CY - Online meeting
DA - 14.11.2021
KW - Dipsersive XAS
KW - Mechanochemistry
KW - Time-resolved
KW - In situ
PY - 2021
AN - OPUS4-56256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Detektion von Mikroplastik
N2 - In dem Vortrag geht es um die Möglichkeiten der Detektion von Mikroplastik im Allgemeinen. Es werden Beispiele für die Luft gezeigt.
T2 - VDI-Workshop „Mikroplastik in der Außenluft – Was wir wissen und was wir (noch) nicht wissen
CY - Online meeting
DA - 15.11.2022
KW - Mikroplastik
KW - Mikroplastik in Luft
KW - Detektion von Mikroplastik
PY - 2022
AN - OPUS4-56289
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waniek, Tassilo
T1 - MNP test and reference material production
N2 - Reference materials are essential to analyze the impact of micro- and nanoplastics. The particle size D50 has been chosen as property of interest. They can be produced top-down by milling. For size separation down to a particle size D50 of 50 µm sieving is suitable while smaller particle sizes can be obtained by filtration. After production it is important to control the stability because microplastic in the size range below 10 µm tend to agglomerate.
T2 - CUSP early-stage researchers meeting
CY - Online meeting
DA - 08.11.2022
KW - Particale size
KW - Microplastic
KW - Reference material
KW - Cryo milling
KW - Polymer
PY - 2022
AN - OPUS4-56214
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Micro- and Nanoplastics: from physico-chemical properties to reference products
N2 - In this presentation we demonstrate the importance of physico-chemical properties (pc) of micro- and nanoplastic particles (MNPs). These properties determine interaction between MNPs and cells or living organisms. To perform accurate experiments for acquiring pc information it is essential to develop well-characterized and understood plastic reference materials. Such reference materials can be used in interlaboratory comparisons (ILCs). BAM is organizing under VAMAS two ILCs, on micro- and nanoplastics to obtain reliable results and methodologies for pc characterization of MNPs. By gaining profound knowledge on pc properties it becomes possible to estimate the impact of MNPs on the humans and environment and therefore to translate the knowledge to the level of regulation.
T2 - CUSP early-stage researchers meeting
CY - Online meeting
DA - 08.11.2022
KW - Micro- and nanoplastics
KW - Plastic reference materials
KW - Interlaboratory Comparisons
PY - 2022
AN - OPUS4-56330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Evolution of mesoporous frameworks from precipitated struvite-structured metal phosphate materialsls
N2 - Mesoporous transition metal phosphates (TMPs) have attracted major interest due to their high (electro-)catalytic activity suitable for H2 generation, supercapacitors or batteries. Typically, mesoporous materials are synthesized via a template-based route. This way is in the case of TMP because the surfactants used are difficult to remove due to the sensitivity of the mesoporous framework. We present a template-free method including the formation of a precursor phase called M-struvite (NH4MPO4•6H2O, M = Mg2+, Ni2+, Co2+, Ni2+xCo2+1-x) to synthesize mesoporous and amorphous metal phosphates. This method relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneous mesoporous phase associated with the degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the coordination metal coordination environment was followed with diffraction and spectroscopy based in-situ and ex-situ methods. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions between the chemical systems. In a complex amorphous structure, thermal decomposed Mg-, Ni- and NixCo1-x-struvites exhibit high surface areas and pore volumes for phosphate materials with a spherical to channel-like pore geometry (240 m²g-1 and 0.32 cm-3 g-1 for Mg and 90 m²g-1 and 0.13 cm-3 g-1 for Ni). In addition to this low-cost, environmentally friendly and simple synthesis, M-struvites could grow as a recycling product from industrial and agricultural wastewaters. These waste products could be upcycled through a simple thermal treatment for further applications.
T2 - SNI 2022 - German Conference for Research with Synchrotron Radiation, Neutrons and Ion Beams at Large Facilities
CY - Berlin, Germany
DA - 05.07.2022
KW - Struvite
KW - Transition metal
KW - Phosphate
KW - Amorphous phases
KW - Mesoporosity
PY - 2022
AN - OPUS4-55911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, U.
T1 - Thermoanalytical methods to measure mass in microplastics
N2 - The talk adresses the use of thermoanalytical methods in microplastics analysis.
T2 - EUROLAB webinar: MICROPLASTICS: regulations, standards and the role of laboratories
CY - Online meeting
DA - 15.02.2023
KW - TED-GC/MS
KW - Thermoanalytical methods
KW - Microplastic mass
PY - 2023
AN - OPUS4-57009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heilmann, Maria
T1 - Size-Tunable Ni-Cu Core-Shell Nanoparticles: Structure, Composition, and Catalytic Activity
N2 - Nanoparticles (NPs) have become important materials for a variety of chemical technologies, including catalysis. One of the main challenges is the reduction of green house gases, such as CO2. One opportunity besides the capturing is the conversion to synthesis gas via the reverse water-gas shift reaction.
A facile and efficient method is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core-shell NPs. The diameter of the NPs can be tuned in a range from 6 nm to 30 nm and the Ni:Cu ratio from 30:1 to 1:1. The NPs are structurally characterized with combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray photoelectron spectroscopy, and X-ray absorption fine structure. Using these analytical methods, a core-shell-shell structure their chemical composition is elucidated. A depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core-shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction).
T2 - Nanoalloys: recent developments and future perspectives Faraday Discussion
CY - London, UK
DA - 21.09.2022
KW - Nanoparticles
KW - Core-shell
KW - Catalysis
PY - 2022
AN - OPUS4-56831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Release of synthetic fibres during washing of typical household textiles: Findings from washing machine tests and resulting policy recommendations
N2 - This talk summarizes the experimental setup and the results of one washing experiment under realistic conditions according to microplastic fiber release.
T2 - Tackling microplastics in the environment
CY - Brussels, Belgium
DA - 09.03.2023
KW - Microplastics
KW - Fibers of textile origin
KW - Washing machine
KW - Microplastic fibre release
PY - 2023
AN - OPUS4-57204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Linberg, Kevin
T1 - Polymorphism in molecular cocrystals controlled by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify or synthesize new crystal forms. Although the method is very promising, little is known about the mechanochemical means to control the synthesis of a solid form. Using an polymorphic organic cocrystal system, we show here that mechanochemistry can be used to obtain a polymorph transformation under the apparently conventional (thermal) transition point.
T2 - Bessy User Meeting 2022
CY - Online meeting
DA - 08.12.2022
KW - Mechanochemistry
KW - Polymorphism
KW - TRIS
PY - 2022
AN - OPUS4-56473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - How do transition metal phosphates crystallise?
N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we investigate the crystallization of transition metal phosphate (TMP) compounds (NH4MPO4∙6H2O, M3(PO4)2∙8H2O with M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate) out of aqueous solutions, which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters has high potential as a P- and 3d metal recovery route. For this purpose, a detailed understanding of the crystallization process beginning from combination of solved ions and ending in a final crystalline product is required. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMPs could be controlled. Detailed investigations of the precipitation process in time using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases during the crystallization process. Over time, their complex amorphous framework changes significantly resulting simultaneously in an agglomeration and densification of the compound. After extended reaction times these colloidal nanophases condensed to a final crystal. However, the reaction kinetics of the formation of a final crystalline product and the lifetime of these intermediate phases vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications.
T2 - Granada Münster Discussion Meeting (GMDM)
CY - Granada, Spain
DA - 30.11.2022
KW - Struvite
KW - Transition metal
KW - Phosphates
KW - Amorphous phases
KW - Non-classical crystallization
PY - 2022
AN - OPUS4-56478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Crystallization study of transition metal phosphates: a new example for non-classical crystallization theory
N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.), which contain high concentrations of NH4+, PO43- and transition metals, are environmentally harmful due to their toxic pollutants. At the same time, phosphorus and selective transition metals such as Cobalt could be potentially depleted as a critical raw material due to the high demand and rapidly declining natural ore deposits. Therefore, due to simultaneous scarcity and abundance, the phosphorus and 3d metal recovery from agricultural, industrial, mining, or urban wastewaters have been an important factor in sustaining our global consumption and preservation of the natural environment. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we report the synthesis routes for transition metal phosphate (TMP) compounds (M3(PO4)2∙8H2O, NH4MPO4∙6H2O, M = Ni2+, Co2+, NixCo1-x2+ M-struvite and M-phosphate octahydrate), which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters could be a promising P-recovery route. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMP could be controlled. Detailed investigations of the precipitation process using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases which subsequently aggregate and condense to final crystals after extended reaction times. However, the reaction kinetics of the formation of a final crystalline product vary significantly depending on the metal cation involved in the precipitation process. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The mixed NixCo1-x system shows a significantly different crystallization behavior and reaction kinetics of the precipitation compared to the pure endmembers. The observed various degree of stability could be linked to the octahedral metal coordination environment in these compounds. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications.
T2 - Adlershofer Forschungsforum 2022
CY - Berlin, Gemany
DA - 11.11.2022
KW - Transition metal
KW - Phosphates
KW - Non-classical crystallization
KW - In-situ SAXS/WAXS
KW - Cryo-TEM
PY - 2022
AN - OPUS4-56479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Exploring amorphous lewis-acidic zirconium chloro fluoride as a heterogeneous HF shuttle
N2 - Owing to a growing shortage of fluorspar, a raw material used for producing fluorinated base chemicals, fluorspar has been named among the 30 critical raw materials in the EU. 1 However, the sustainable transfer of fluorine atoms from one molecule to another using heterogeneous catalysts has not yet been reported. Herein, we present the heterogeneous catalyst zirconium chloro fluoride (ZCF) that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
T2 - InSynX Workshop 2023
CY - Sao Paulo, Brazil
DA - 06.03.2023
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
PY - 2023
AN - OPUS4-57228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Metal fluoride surfaces by protonation with surface immobilized HF
N2 - Lewis-acidic zirconium or chromium fluoride surfaces on
different aluminium oxide or fluoride substrates.
T2 - CRC 1349 Symposium 2021
CY - Berlin, Germany
DA - 25.11.2021
KW - HF
KW - Heterogeneous catalysis
PY - 2021
AN - OPUS4-57226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Recycled transition metal phosphates as functional materials for electrochemistry
N2 - In the last decade transition metal phosphates (TMPs) captured major interest due to their high electrochemical activity useful for electrode materials, supercapacitors or batteries. Importantly, TMPs are known to exhibit high proton conductivity of the order of >10-2 -10-5 S/cm from 25°C to temperatures as high as 400°C. The crucial milestone in the research on the applicational use of TMPs in all their varieties is an ability to obtain, explore and optimize different compositions and structures, both crystalline and amorphous. Thus, we elucidate the structures of amorphous and crystalline Ni- and Co phosphate phases, as they develop upon heating. This method relies on the thermal decomposition of a crystalline M-struvite precursor, i.e. NH4MPO4•6H2O (M = Mg, Ni, Co, NixCo1-x etc. Here, coincidently volatile components such as H2O or NH3 degas out of the compound resulting in a phase transformation to amorphous or crystalline metal phosphate phases depending on the reaction conditions.
For this we used a suite of advanced methods such as FTIR, FT-RS and synchrotron-based XAS. Ni-struvite transforms to amorphous phases over a broad range of temperatures (90°C < T < 600°C) in which it remains in an octahedral coordination environment. On the other hand, Co-struvite treatment leads to multiple crystalline phases with only small amounts of short-lived amorphous phases.
Importantly, the occurring amorphous phases exhibit uniform mesoporous frameworks (2–5 nm wide pore channels, specific surface area of 100 m2g−1 and a pore volume of 0.13 cm3g−1) at low temperatures (<200°C) while the crystalline compounds can be used as proton conductors demonstrating values of >10-4 S/cm at 25°C. Consequently, we investigated the amorphization/evolution of mesoporosity, the proton-conducting properties and the complex local structure with in- and ex-situ approaches during thermal treatment. Additionally, to this low cost, environmentally friendly and simple one pot synthesis, the precursor M-struvites could grow as a recovery product from industrial waste waters. In such a way, they would to a recycling economy of sought-after commodities like phosphorus or transition metals.
T2 - E-MRS Spring Conference 2023
CY - Strasbourg, France
DA - 29.05.2023
KW - Struvite
KW - Transition metals
KW - Phosphates
KW - Functional materials
KW - Mesoporosity
KW - Proton conductivity
PY - 2023
AN - OPUS4-57587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, D.
A1 - Megha, S. N.
A1 - Kiran, M. S. R. N.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Designing the Mechanical Plasticity of Benzylidene Indanones Based Molecular Crystals by Crystal Engineering
N2 - Mechanically flexible molecular crystals have important implications in flexible optoelectronics, optical waveguides, etc. We report a series of 2-benzylidene 1-indanone based plastic crystals. Moreover, we have shown how plasticity can be fine-tuned through controlling intermolecular interactions.
KW - Mechanical flexibility
KW - Organic crystal
KW - Mechanical property
PY - 2023
DO - https://doi.org/10.1021/acs.cgd.2c01137
SN - 1528-7483
VL - 23
SP - 657
EP - 661
PB - ACS Publications
AN - OPUS4-57773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernardes, C. E. S.
A1 - Feliciano, I.O.
A1 - Naese, Christoph
A1 - Emmerling, Franziska
A1 - Minas da Piedade, M.
T1 - Energetics of dehydroepiandrosterone polymorphs I and II from solution and drop-sublimation Calvet microcalorimetry measurements
N2 - The lattice enthalpies and monotropic relationship of two dehydroepiandrosterone (DEHA) polymorphs (forms I and II) were evaluated through a combination of differential scanning calorimetry (DSC), isothermal solution microcalorimetry, and drop-sublimation Calvet microcalorimetry experiments. The standard molar enthalpy of transition between both forms was determined as ΔtrsHom (II→I, 298.15 K) = - 0.90 ± 0.07 kJ mol-1 and ΔtrsHom (II→I, 417.8 K) = - 1.7 ± 1.0 kJ mol- 1, from measurements of standard molar enthalpies of solution in dimethyl sulfoxide and enthalpies of fusion, respectively. Drop-sublimation Calvet microcalorimetry experiments on form I led to ΔsubHom (cr I, 298.15 K) = 132.0±3.3 kJ mol - 1. This result, when combined with the more precise ΔtrsHom (II→I) value obtained by solution calorimetry, afforded ΔsubHom (cr II, 298.15 K) = 131.1±3.3 kJ mol - 1. The overall data indicate that on enthalpic grounds form I is more stable than form II from 298.15 K up to fusion. This conclusion, and the fact that DSC experiments indicated that form I has also a considerably higher temperature fusion, namely, Tfus(cr I)= 422.5±0.2 K and Tfus(cr II) = 413.1±0.2 K, suggest that the two polymorphs are monotropically related.
KW - Calorimetry
KW - Polymorphism
KW - Enthalpy of solution
KW - Enthalpy of sublimation
KW - Thermochemistry
KW - Lattice enthalpy
PY - 2023
DO - https://doi.org/10.1016/j.jct.2023.107137
SN - 0021-9614
SN - 1096-3626
VL - 186
SP - 1
EP - 7
PB - Elsevier
AN - OPUS4-58418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wiesner, Yosri
T1 - Metrological Observation of the Stability Performance of Reference Materials for Microplastic Analysis
N2 - The formation of microplastic (MP) particles (1-1000 µm) is mostly related to physicochemical degradation processes of macroplastics. Photooxidative damage is often set as the initial degradation process, which leads to embrittlement of the plastics. Mechanical processes then lead to further fragmentation and the formation of MP particles. In the environment, this can be associated with UV exposure through direct radiation from the sun, which leads to radical formation in the polymer systems on the one hand and radical formation of oxygen on the other. The result is material embrittlement usually caused by chain shortening in the polymeric system. Due to specific ecosystem conditions, the damaged polymer is fragmented by erosive, abrasive processes or wave action.
According to reference material topic for MP analysis, pristine and artificially weathered polymers are needed. Starting from granulate or macroplastics, these can be pulverised with different techniques, bottled and stored until usage. The bottled powders need to be homogen and stable over a defined time interval regarding to a specific property.
This work deals with different polymer types, aged and non-aged. It tries to answer the question under which storage conditions polymers will be stable in particle size. The powders are characterized for chemical composition and shape with FTIR, DSC and SEM. Particle size distribution was measured by laser diffraction with wet and dry dispersion. Artificially pre-aged materials seem to be more vulnerable for further aging and less stable in particle size distribution measurements.
T2 - SETAC Dublin– SETAC Europe 33nd Annual Meeting
CY - Dublin, Ireland
DA - 30.04.2023
KW - Reference material
KW - Microplastics
KW - Metrological Observation
PY - 2023
AN - OPUS4-57475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Linberg, Kevin
T1 - Controlled Polymorphism by Elevated Temperature Ball Milling
N2 - Mechanochemistry provides polymorphs that are difficult to obtain by conventional solution-based methods. Based on the nicotinamide and pimelic acid cocrystal, we demonstrated that the ball size, frequency, and temperature are essential parameters. Our results indicate that fine-tuning the energy input during a mechanochemical reaction can provide control over polymorphism.
T2 - Bessy User Meeting 2023
CY - Berlin, Germany
DA - 22.06.2023
KW - Mechanochemistry
KW - Temperature
KW - Cocrystal
KW - Energy input
KW - Polymorph
PY - 2023
AN - OPUS4-57985
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - Zirconium chloro fluoride as catalyst for C-F bond activation and HF transfer of fluoroalkanes
N2 - In this work, we successfully synthesized amorphous zirconium chloro fluoride (ZCF), which exhibits medium lewis acidity. In addition to investigating the local coordination sphere around the Zr atoms and the material properties, we were able to establish a catalytic behavior of ZCF in C-F bond activation reactions. We present a heterogeneous catalyst that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
T2 - MC 16
CY - Dublin, Ireland
DA - 03.07.2023
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
PY - 2023
AN - OPUS4-58052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miclea, P.-T.
T1 - Micro- and nanoplastic particle number and mass-based analysis on a plastic-free size-selective two stage Si membrane filtration cascade
N2 - The poster presents a Si wafer filter development as two stage cascade and the adapter for microplastics filtration.
T2 - SETAC Europe 2023
CY - Dublin, Ireland
DA - 30.04.2023
KW - Microplastics
KW - Filtration
KW - TED-GC/MS
KW - Polymer 3R
KW - Cascade filtration
PY - 2023
AN - OPUS4-57461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miclea, P.-T.
T1 - Real-life airborne micro- and nano-plastic particles and fibres on a porous membrane filter system from a textile factory suitable for both: vibrational and mass spectrometry
N2 - The poster presents an application of Si wafer filter system on indoor air sampling. A textile factory producing PP fibres was sampled.
T2 - SETAC Europe 2023
CY - Dublin, Ireland
DA - 30.04.2023
KW - Microplastics
KW - Polymer 3R
KW - Textile fibres
KW - Si wafer filter
KW - Microplastics sampling
PY - 2023
AN - OPUS4-57462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Overview of CUSP and PlasticTrace
N2 - The presentation summarises the work of CUSP and PlasticTrace EU joint research projects of the last year.
T2 - Microplastics Scientific Workshop of PlasticsEurope
CY - Amsterdam, The Netherlands
DA - 08.05.2023
KW - Microplastics
KW - Microplastics standardisation
KW - Reference materials
KW - Polymer 3R
PY - 2023
AN - OPUS4-57460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Material Selection Strategy
N2 - This poster is a summary of the material used in the PlasticsFatE project. It indicates the strategies for testing of various polymer properties next to each other according to risk and hazard assessment.
T2 - CUSP annual meeting and conference
CY - Utrecht, Netherlands
DA - 12.09.2023
KW - Microplastics
KW - CUSP
KW - Material selection
PY - 2023
AN - OPUS4-58311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, Deepak
A1 - Ahmad, Shamim
A1 - Tothadi, Srinu
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, Soumyajit
T1 - Linker size dependent mechanical properties of di-imine based molecular crystals
N2 - We have demonstrated the ability to modify the mechanical flexibility of molecular crystals by modulating the length of intervening linker moieties while keeping the terminal shape synthons the same.
KW - Mechanically flexible molecular crystals
KW - Mechanical properties
KW - Crystal Engineering
PY - 2023
DO - https://doi.org/10.1039/D3CE00928A
SN - 1466-8033
SP - 1
EP - 8
PB - RSC
CY - London
AN - OPUS4-58836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hoell, A.
T1 - On the usage of anomalous SAXS to analyzethe structure and composition of bimetallic nanoparticles and quantum dots
N2 - Tailor-made nanoparticles are of increasing interest in e.g. catalysis, as sensor materials, analytical assays, or can have superior photophysical properties. A major issue concerning the preparation of high-quality and functional nanoparticles is a good control of particle size, shape, polydispersity, and composition.
Small Angle X-ray Scattering (SAXS) is a non-destructive method for the analysis of nanostructures in a wide variety of materials. This method allows determining averaged structural parameters on a length scale from just above atomic sizes up to several 100 nanometers such as sizes, size distributions, volume fractions, and inner surface sizes. Moreover, anomalous Small Angle X-ray Scattering (ASAXS) exploits the anomalous dispersion of the scattering amplitudes near the X-ray absorption edges of the elements contained in the sample. These element sensitive contrast variations can be used to analyse average composition fluctuations on the nm scale. Two kinds of nanoparticles are chosen here to elaborate the advantages of ASAXS in the analysis of complex materials.
A facile and efficient methodology is developed for the thermal synthesis of size-tunable, stable, and uniform bimetallic NiCu core–shell nanoparticles (NPs) for various application in catalysis. Their diameter can be tuned in a range from 6 nm to 30 nm and the Ni:Cu ratio is adjustable in a wide range from 1:1 to 30:1. The NPs are structurally characterized by a method combination of transmission electron microscopy, anomalous small-angle X-ray scattering (ASAXS), X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Here, we focus on the ASAXS method and its ability to analyses nanostructure parts and their compositions at once. As a result, a NiCu alloyed core surrounded by a Ni enriched shell and an outer NiO shell was found.
Semiconductor nanocrystals (quantum dots, QDs) are well known for their superior photophysical properties and enabled advancements in several key technologies of the 21st century and numerous technological applications like in photovoltaics, LED displays, photocatalysis, and biosensing. To achieve high photoluminescence quantum yields (PLQY) and enhanced photostability the QD core needs to be passivated by a second semiconductor, which possess a larger band gap to confine the charges within the QD core. An important parameter is thereby the lattice mismatch between the core and shell. To avoid strong lattice strain, which would alter the photophysical properties, an intermediary shell can be used as a lattice adapter between the core and the outer shell leading to core/shell/shell systems. These systems have shown to possess high PLQYs combined with a strong long-term stability and can be found in modern QLED displays. ASAXS was used here to better understand the core/shell/shell structure of InP/ZnSe/ZnS QDs to enable a correlation between their structural and photophysical properties.
T2 - IUCr - International Union of Crystallography
CY - Melbourne, Australia
DA - 22.08.2023
KW - ASAXS
KW - Quantum dot
KW - Core/shell materials
KW - Safer by design
PY - 2023
AN - OPUS4-58812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Current projects in risk assessment and harmonisation
N2 - The talk gives an overview about EU projects currently running for risk assessment and harmonisation in microplastic analysis.
T2 - Micro- and Nanoplastics
CY - Halle (Saale), Germany
DA - 01.11.2023
KW - Microplastics
KW - Harmonisation in microplastics
KW - Polymer 3R
PY - 2023
AN - OPUS4-58766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Visileanu, E.
T1 - Methods for the collection and characterization of airborne particles in the textile industry
N2 - The presentation summarizes possibilities to sample airborne micro and nanoplastic particles. An example of a textil company is shown.
T2 - 5th International Conference on Human Systems Engineering and Design: Future Trends and Applications (IHSED 2023
CY - Dubrovnik, Croatia
DA - 27.09.2023
KW - Microplastics
KW - Polymer 3R
KW - Textile company
PY - 2023
AN - OPUS4-58561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - A fluorolytic sol-gel route to access an amorphous Lewis-acidic Zr fluoride catalyst
N2 - The Kemnitz et al. developed a fluorolytic route to access metal fluorides 1 such as AlF3 2 and MgF2 3 which possess a high surface area. In aluminium-based systems, the synthetic approach led to amorphous xerogels that can be further converted into Lewis superacids.2 Still, despite zirconium oxide being described as a stronger Lewis acid than other metal oxides4 zirconium fluoride-based materials have only recently been reported or investigated. In this work we extend the class of amorphous Lewis acidic heterogeneous catalysts to an amorphous ZrF4 that is active in C-F bond activation.
T2 - CRC 1349 Summer School 2023
CY - Berlin, Germany
DA - 28.08.2023
KW - ZrF4
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - Postfluorination
PY - 2023
AN - OPUS4-58638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hein-Paar, Jakob
T1 - Spectroscopic Insights into the Reactivity of Energetic Materials
N2 - Energetic materials (explosives, propellants, pyrotechnics, and gas generators; EM) release large amounts of energy when initiated by mechanical loading and have many technological applications including in energy storage and propulsion. The accidental initiation of an EM – particularly in the wrong setting – has the potential to be catastrophic. Unfortunately, there is little understood about what determines the sensitivity of a given EM. This poses severe restrictions on our ability to design new and safer EMs.
Aiming to better understand the initiation mechanisms of EMs, we here investigate the reactivity of simple, isomorphous azides (MN3 M=Li, Na). Both metal azides contain the same explosophoric azido anions, but differ significantly in their reactivity, presumably owing to different bonding interactions between the anion and the metal cation. This interaction offers a promising probe for X-ray spectroscopy and quantum chemical simulations. In noting that mechanical initiation results from mechanical impact – with high local pressures – we are particularly interested in identifying how this bonding interaction changes as a function of pressure.
This interaction offers a promising probe for X-ray spectroscopy and quantum chemical simulations. In noting that mechanical initiation results from mechanical impact – with high local pressures – we are particularly interested in identifying how this bonding interaction changes as a function of pressure.
Here we show results from DFT simulations that indicate a shift in electronic structure and changes in the metal-azide bond with increasing pressure, which is further investigated through experimental XAS spectra. Together, our results show promising insights into the behaviour of simple metal azide EMs.
T2 - SXR2023 - Principles of Functionality From Soft X-Ray Spectroscopy
CY - Berlin, Germany
DA - 11.09.2023
KW - Energetic materials
PY - 2023
AN - OPUS4-58824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Purohit, Akash M
A1 - Patel, Rishi I
A1 - Bhatt, Vidhi
A1 - Mosaffa, Elias
A1 - Bhattacharya, Biswajit
A1 - Manna, Arun K
A1 - Iyer, Bragadish
A1 - Emmerling, Franziska
A1 - Banerjee, Atanu
T1 - Solvent induced ligand transmuted substituted pyrazole housed copper complexes: Synthesis, characterization, DFT and anti-microbial performance
N2 - Pyrazole-based ligand systems 3,5-dimethylpyrazole (L1) and 1-hydroxymethyl-3,5-dimethylpyrazole (L2OH) were synthesized and utilized to form copper complexes in various solvent environments. The ligand L2OH exhibits significant solvent-induced ligand transformation in polar protic solvent. The structural and electronic characteristics of the synthesized complexes were elucidated by X-ray single crystallography, Fourier Transform Infrared (FTIR) and electronic spectroscopy (UV-VIS). Whereas the ligand transformation has been evidenced from FTIR and Nuclear Magnetic Resonance (NMR) spectroscopic techniques. Furthermore, Density Functional Theory (DFT) highlights the pivotal role of solvent effects in modulating ligand transformations and complex formation, contributing to the rational design of metal-based bioactive compounds. Electronic transitions of the metal complexes have been analysed by time-dependent DFT (TD-DFT) calculations. The findings reinforce the significance of transition metal complexes in the development of antimicrobial agents and metallo-pharmaceuticals. The synthesized pyrazole compounds showed 100% inhibition against bacterial strains Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis and the yeast Candida albicans at a concentration ranging from 3.9 to 62.5 µg/ml depending upon the strain tested.
KW - Pyrazole derivatives
KW - Antibacterial and antifungal activity
KW - Solvent induced ligand transformation Copper complexes
KW - DFT study
PY - 2025
DO - https://doi.org/10.1016/j.molstruc.2025.143001
SN - 0022-2860
VL - 1345
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-63746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Booth, A.
T1 - Production of a 1-10 μm polypropylene reference material for development of analytical methods
N2 - The poster is about the preparation of microplastics in the size range of 1-10 µm. These size range of particles can be inhalded and therefore be toxic for humans. The preparation is done by comminution of PP pellets and sieving. Characterisation occured for size with laser diffraction, for type with FTIR and for shape with SEM.
T2 - SETAC Europe 2025
CY - Vienna, Austria
DA - 11.05.2025
KW - Microplastics
KW - Reference materials
PY - 2025
AN - OPUS4-63367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Holistic Experimentation in the HExX-Lab
N2 - Through bottom-up, comprehensive digitalisation of all aspects of an experiment, the HEX-lab improves the trustworthiness (traceability, reproducibility, quality) of scientific findings.
The five main parts that make up a materials science experiment, i.e. Sample preparation, Measurements, Processing, Analysis, and Interpretation, each have been addressed in thorough and unique ways in this lab, building up a foundation for a wide range of materials science collaborations. Improvements span the spectrum.
Hardware developments include new sample environments and stages, such as grazing incidence motion towers, electrochemistry cells and flow-through holders, electronic components such as safety interlocks and multipurpose I/O controllers, and liquid handling systems such as coolant flow cross-over systems.
Software developments include:
1) a new comprehensive control system operating on both the RoWaN as well as the MOUSE allowing for full Python control and sequencing of all experimentation,
2) Automated scripts for instrument optimization, sample alignments and measurements,
3) revamped data pipelines and analysis software, standalone or launched as part of operations sequencing dashboards on servers, and
4) meticulously structured archival datafiles, fully documenting sample preparation, measurements, processing and analyses. These allow for holistic databases and dashboards to be constructed to investigate the links between synthesis parameters and resulting morphology.
This poster will highlight some of the tools and techniques developed and available in the HEX-lab over the years, from sample environments to overarching experiment and data organisation structures.
T2 - Materials Science Core Facility Synergy Forum 2025
CY - Bremen, Germany
DA - 26.02.2025
KW - Digitalization
KW - Holistic experiments
KW - Traceability
KW - Data provenance
PY - 2025
AN - OPUS4-62675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czeskleba, Denis
A1 - Rhode, Michael
A1 - Wandtke, Karsten
A1 - Irfan, Muhammad Dary
A1 - Kannengiesser, Thomas
T1 - Hydrogen diffusion in thick-walled S690 saw joints: part 1—experimental determination of microstructure-dependent diffusion coefficients
N2 - High-strength low-alloyed steel S690 is widely used in heavy-duty applications, such as structural components, mobile cranes, and industrial plant construction, owing to their high strength and weldability. However, thick-plate submerged arc welding (SAW) can introduce elevated hydrogen levels and residual stresses that promote time-delayed hydrogen-assisted
cold cracking (HACC). Accurate, microstructure-specific diffusion data are scarce, limiting predictive HACC assessments. This study presents an experimental determination of hydrogen diffusion coefficients (DH) in two S690 variants: thermomechanically rolled (S690MC) and quenched and tempered (S690Q). Multi-layer SAW welds were produced from 30 mm thick plate material at three heat input levels, and diffusion membranes were extracted from weld metal (WM), heat-affected zone (HAZ), and base material (BM). Hydrogen permeation tests, conducted in accordance with DIN En ISO 17081, yielded flux curves normalized in time from which DH was derived using the inflection-point method. At room temperature, DH values ranged from 6 × 10−5 mm2/s to 9 × 10−5 mm2/s across all regions and heat inputs, with no significant difference between S690MC and S690Q. Weld metal exhibited marginally lower DH, attributed to enhanced hydrogen trapping, while base material measurements showed greater variability. These microstructure-resolved diffusion coefficients add quantitative data for modern S690 SAW welds and provide internally consistent input parameters for the numerical simulations presented in part 2. The results support improved parameterization for subsequent assessments of HACC risk through the optimization of welding parameters.
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - Diffusion
KW - Electrochemical permeation
KW - Microstructure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655711
DO - https://doi.org/10.1007/s40194-026-02400-7
SN - 0043-2288
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-65571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - In-situ analysis of nucleation processes – case study: calcium sulfate
N2 - In this project we investigate nucleation pathways by utilizing synchrotron-XRD and running a case-study on calcium sulfate phases. To accomplish this, we developed a modular automation setup for reactions in solution to run synthesis and control reaction conditions. So far we successfully characterized the recycling process of gypsum and are now investigating the formation of anhydrite.
T2 - BESSY@HZB User Meeting
CY - Berlin, Germany
DA - 02.12.2025
KW - Recycling
KW - Gypsum
KW - Synchrotron-X-ray-diffraction
KW - Raman-spectroscopy
KW - Automation
PY - 2025
AN - OPUS4-65344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czeskleba, Denis
A1 - Rhode, Michael
A1 - Wandtke, Karsten
A1 - Irfan, Muhammad Dary
A1 - Kannengiesser, Thomas
T1 - Hydrogen diffusion in thick-walled S690 SAW joints: part 2 – predictive modeling of heat input and microstructure influence
N2 - High-strength low-alloy (HSLA) steels such as S690 are widely employed in thick-walled welded structures, where hydrogen-assisted cold cracking (HACC) remains a persistent concern. While microstructure-specific hydrogen diffusion coefficients (DH) for weld metal (WM), heat-affected zone (HAZ), and base material (BM) were experimentally established in Part 1 of this study, their quantitative influence on hydrogen accumulation and effusion has not yet been fully clarified. This work presents a transient, spatially resolved numerical model for simulating hydrogen transport in multi-pass submerged arc welds. The model integrates experimentally determined DH values with realistic thermal cycles and temperature-dependent boundary conditions. Developed in Python, the simulation tool is purpose-built for hydrogen diffusion in welded joints. It offers a focused, transparent alternative. It offers a focused, transparent alternative to general-purpose finite element platforms. Parametric analyses demonstrate that, although the diffusion coefficients vary by up to 50%, their impact on overall hydrogen retention is minor. In contrast, plate thickness, bead geometry, cooling time (t₈/₅), and interpass temperature exert a dominant influence on hydrogen distribution. Despite clear microstructural differences between the thermomechanically rolled (S690MC) and quenched and tempered (S690Q) variants, including opposite HAZ hardness responses (softening in S690MC, hardening in S690Q) in the (pen)ultimate weld bead, the simulations confirm that their diffusion behavior and hydrogen solubility are closely aligned. Consequently, differences in DH and solubility exert only a minor influence on hydrogen retention compared to thermal exposure and joint geometry. These findings support the interchangeable use of both steel grades in terms of HACC risk due to hydrogen diffusion kinetics under comparable welding conditions.
KW - Hydrogen assisted cracking
KW - Numerical simulation
KW - Diffusion
KW - Submerged arc welding
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655721
DO - https://doi.org/10.1007/s40194-026-02395-1
SN - 0043-2288
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seifert, Lando
T1 - Grundlagen Korrosion und Korrosionsschutz
N2 - Im Rahmen des jungen gfkorr Events an der Universität Kassel in diesem Jahr wurde der Grundlagenvortrag vor Young Professionals und Studierenden vorgestellt.
Die BAM beschäftigt sich im Fachbereich 7.6 schwerpunktmäßig mit der Korrosionsprüfung, den Korrosionsschäden und -reaktionen rund um Anwendungsfälle der Hauptkonstruktionswerkstoffe Stahl, verzinkter Stahl, Nichtrostende Stähle und Aluminium in relevanten Umgebungsbedingungen.
Der Impulsvortrag sollte die Faszination für die Korrosion übermitteln. Dabei wurde anhand von Schadensfällen grundlegende Mechanismen und Haupteinflussfaktoren erörtert. Gestartet wurde mit einem prominenten Versagensfall und Beispiel für Spaltkorrosion aus der Luftfahrt...
T2 - die junge gfkorr @ Universität Kassel
CY - Kassel, Germany
DA - 02.03.2026
KW - Korrosion
KW - Korrosionsschutz
KW - Stahl
KW - Zink
KW - Aluminium
KW - Nichtrostende Stähle
KW - Korrosivität
KW - Spaltkorrosion
PY - 2026
AN - OPUS4-65614
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Prinz, Carsten
A1 - Zimathies, Annett
A1 - Emmerling, Franziska
T1 - Experimental raw data sets associated with certified reference material BAM-P115 (titanium dioxide) for comparison of nitrogen and argon sorption, available in the universal adsorption information format (AIF)
N2 - These data sets serve as models for calculating the specific surface area (BET method) using gas sorption in accordance with ISO 9277.
The present measurements were carried out with nitrogen at 77 Kelvin and argon at 87 Kelvin.
It is recommended to use the following requirements for the molecular cross-sectional area:
Nitrogen: 0.1620 nm²
Argon: 0.1420 nm²
Expected specific surface area for nitrogen (BET): 140 to 154 m²/g
Expected specific surface area for argon (BET): 129 to 135 m²/g
Titanium dioxides certified with nitrogen sorption and additionally measured with argon for research purposes were used as sample material.
The resulting data sets are intended to serve as comparative data for own measurements and show the differences in sorption behaviour and evaluations between nitrogen and argon.
These data are stored in the universal AIF format (adsorption information format), which allows flexible use of the data.
KW - Physisorption
KW - Specific surface area
KW - AIF
KW - Argon
KW - Nitrogen
PY - 2024
DO - https://doi.org/10.5281/zenodo.13269756
PB - Zenodo
CY - Geneva
AN - OPUS4-60783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monikh, F. A.
A1 - Baun, A.
A1 - Hartmann, N. B.
A1 - Kortet, R.
A1 - Akkanen, J.
A1 - Lee, J.-S.
A1 - Shi, H.
A1 - Lahive, E.
A1 - Uurasjärvi, E.
A1 - Tufenkji, N.
A1 - Altmann, Korinna
A1 - Wiesner, Yosri
A1 - Grossart, H.-P.
A1 - Peijnenburg, W.
A1 - Kukkonen, J. V. K.
T1 - Exposure protocol for ecotoxicity testing of microplastics and nanoplastics
N2 - Despite the increasing concern about the harmful effects of micro- and
nanoplastics (MNPs), there are no harmonized guidelines or protocols yet available for MNP ecotoxicity testing. Current ecotoxicity studies often use commercial spherical particles as models for MNPs, but in nature, MNPs occur in variable shapes, sizes and chemical compositions. Moreover, protocols developed for chemicals that dissolve or form stable dispersions are currently used for assessing the ecotoxicity of MNPs. Plastic particles, however, do not dissolve and also show dynamic behavior in the exposure medium, depending on, for example, MNP physicochemical properties and the medium’s conditions such as pH and ionic strength. Here we describe an exposure protocol that considers the particle-specific properties of MNPs and their dynamic behavior in exposure systems. Procedure 1 describes the top-down production of more realistic MNPs as representative of MNPs in nature and particle characterization (e.g., using thermal extraction desorption-gas chromatography/mass spectrometry). Then, we describe exposure system development for short- and long-term toxicity tests for soil (Procedure 2) and aquatic (Procedure 3) organisms. Procedures 2 and 3 explain how to modify existing ecotoxicity guidelines for chemicals to target testing MNPs in selected exposure systems. We show some examples that were used to develop the protocol to test, for example, MNP toxicity in marine rotifers, freshwater mussels, daphnids and earthworms. The present protocol takes between 24 h and 2 months, depending on the test of interest and can be applied by students, academics, environmental risk assessors and industries.
KW - Microplastics
KW - TED-GC/MS
KW - Cryo milling
PY - 2023
DO - https://doi.org/10.1038/s41596-023-00886-9
SN - 1754-2189
SP - 1
EP - 38
PB - Nature Protocols
AN - OPUS4-58557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Das, Chayanika
A1 - Emmerling, Franziska
T1 - Mechanochemical Synthesis of Phosphonate-Based Proton Conducting Metal-Organic Frameworks
N2 - Water-stable metal−organic frameworks (MOFs) with proton-conducting behavior have attracted great attention as promising materials for proton-exchange membrane fuel cells. Herein, we report the mechanochemical gram-scale synthesis of three new mixed-ligand phosphonate-based MOFs, {Co(H2PhDPA)(4,4′-bipy)H2O)·2H2O}n (BAM-1), {Fe(H2PhDPA)(4,4′-bipy) (H2O)·2H2O}n (BAM-2), and {Cu(H2PhDPA)(dpe)2(H2O)2·2H2O}n (BAM-3) [where H2PhDPA = phenylene diphosphonate, 4,4′-bipy = 4,4′-bipyridine, and dpe = 1,2-di(4-pyridyl)ethylene]. Single-crystal X-ray diffraction measurements revealed that BAM-1 and BAM-2 are isostructural and possess a three-dimensional (3D) network structure comprising one-dimensional (1D) channels filled with guest water molecules. Instead, BAM-3 displays a 1D network structure extended into a 3D supramolecular structure through hydrogenbonding and π−π interactions. In all three structures, guest water molecules are interconnected with the uncoordinated acidic hydroxyl groups of the phosphonate moieties and coordinated water molecules by means of extended hydrogen-bonding interactions. BAM-1 and BAM-2 showed a gradual increase in proton conductivity with increasing temperature and reached 4.9 × 10−5 and 4.4 × 10−5 S cm−1 at 90 °C and 98% relative humidity (RH). The highest proton conductivity recorded for BAM-3 was 1.4 × 10−5 S cm−1 at 50 °C and 98% RH. Upon further heating, BAM-3 undergoes dehydration followed by a phase transition to another crystalline form which largely affects its performance. All compounds exhibited a proton hopping (Grotthuss model) mechanism, as suggested by their low activation energy.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Proton conductivity
PY - 2022
DO - https://doi.org/10.1021/acs.inorgchem.2c01023
VL - 61
SP - 10801
EP - 10809
PB - ACS Publications
AN - OPUS4-55448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Why shaken, not stirred, makes the difference: insights into mechanochemical reactions from in situ investigations
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity.
Different analytical methods and their combinations have been developed for the time resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy, and thermography.
Here we will discuss our recent results investigating the formation of (poly-morphic) cocrystals[1,3], metal-organic compounds, and salts, thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results.
Our results indicate that time-resolved in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - GdCh Vortrag Universität Potsdam
CY - Potsdam, Germany
DA - 05.06.2023
KW - Mechanochemistry
KW - In Situ
PY - 2023
AN - OPUS4-58982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Mechanochemical formation of multicomponent crystal systems: Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity.
Different analytical methods and their combinations have been developed for the time resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy, and thermography.
Here we will discuss our recent results investigating the formation of (poly-morphic) cocrystals, metal-organic compounds, and salts, thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results.
Our results indicate that time-resolved in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 25th International Conference on the Chemistry of the Organic Solid State (ICCOSS XXV)
CY - Ohrid, Macedonia
DA - 03.07.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Crystal Engineering
PY - 2022
AN - OPUS4-55413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Shaken not stirred: enhancing the flavor of mechanochemistry
N2 - compounds and cocrystals. The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. Time-resolved in situ investigations of milling reactions (Figure 1) provide direct insights into the underlying mechanisms. We recently introduced different setups enabling in situ investigation of mechanochemical reactions using synchrotron XRD and XAS combined with Raman spectroscopy and thermography. The presented setup allows the detection of crystalline, amorphous, eutectic, and liquid intermediates. Furthermore, the chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key to future optimization of mechanochemical syntheses. In this contribution, we will discuss our recent results investigating the formation of (polymorphic) cocrystals and coordination polymers. Our results indicate that time-resolved in situ investigations of mechanochemical processes are key for tuning and optimizing mechanochemical syntheses allowing to unleash the potential of mechanochemistry for a green materials design.
T2 - 2nd National Crystallographic Meeting Lisbon, Portugal
CY - Lisbon, Portugal
DA - 15.07.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Crystal
PY - 2022
AN - OPUS4-55415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Mechanochemical formation of multicomponent crystals systems
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity.
Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography.
Here we will discuss our recent results investigating the formation of (polymorphic) cocrystals, metal-organic compounds, and salts, thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 5ECQUL Forging Bonds
CY - Lisbon, Portugal
DA - 12.07.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - N-Chlorination
PY - 2022
AN - OPUS4-55414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Mechanochemical formation of multicomponent crystal systems: Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new multicomponent crystal systems. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Different analytical methods and their combinations have been developed for the time resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy, and thermography.1 Here we will discuss our recent results investigating the formation of (polymorphic) cocrystals2–3 and metal-organic frameworks,4 thereby elucidating the influence of milling parameters and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved.6 Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 10th International conference on Mechanochemistry and Mechanical Alloying
CY - Cagliari, Italy
DA - 06.06.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Cocrystal
PY - 2022
AN - OPUS4-55421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - ILC on Laser diffraction - preliminary results
N2 - This presentation addresses an interlaboratory comparison on size of polymeric particles (microplastics) measured by laser diffraction. Two microplastic particles were measured separately and once as mixture. Evaluation was done with Fraunhofer and Mie. Here, the first results are presented.
T2 - CUSP Annual Meeting
CY - Utrecht, Netherlands
DA - 12.09.2023
KW - Microplastics
KW - Laser diffraction
KW - Polymer 3R
KW - Size distribution
KW - Polymer size
PY - 2023
AN - OPUS4-58318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Evolution of mesoporous frameworks from precipitated struvite-structured metal phosphate materials
N2 - Mesoporous transition metal phosphates (TMPs) have attracted major interest due to their high (electro-)catalytic activity suitable for H2 generation, supercapacitors or batteries. Typically, mesoporous materials are synthesized via a template-based route. This way is in the case of TMP because the surfactants used are difficult to remove due to the sensitivity of the mesoporous framework. We present a template-free method including the formation of a precursor phase called M-struvite (NH4MPO4•6H2O, M = Mg2+, Ni2+, Co2+, Ni2+xCo2+1-x) to synthesize mesoporous and amorphous metal phosphates. This method relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneous mesoporous phase associated with the degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the coordination metal coordination environment was followed with diffraction and spectroscopy based in-situ and ex-situ methods. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions between the chemical systems. In a complex amorphous structure, thermal decomposed Mg-, Ni- and NixCo1-x-struvites exhibit high surface areas and pore volumes for phosphate materials with a spherical to channel-like pore geometry (240 m²g-1 and 0.32 cm-3 g-1 for Mg and 90 m²g-1 and 0.13 cm-3 g-1 for Ni). In addition to this low-cost, environmentally friendly and simple synthesis, M-struvites could grow as a recycling product from industrial and agricultural wastewaters. These waste products could be upcycled through a simple thermal treatment for further applications.
T2 - ECCG7, European Conference on Crystal Growth
CY - Paris, France
DA - 25.07.2022
KW - Transition metals
KW - Phosphates
KW - Struvite
KW - Amorphous phases
KW - Mesoporosity
PY - 2022
AN - OPUS4-55491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Opitz, P.
A1 - Asta, M.
A1 - Fernandez-Martinez, A.
A1 - Panthöfer, M.
A1 - Kabelitz, Anke
A1 - Emmerling, Franziska
A1 - Mondeshki, M.
A1 - Tremel, W.
T1 - Monitoring a Mechanochemical Syntheses of Isostructural Luminescent Cocrystals of 9-Anthracenecarboxylic Acid with two Dipyridines Coformers
N2 - Amorphous calcium carbonate (ACC) is an important precursor in the biomineralization of crystalline CaCO3. In nature, it serves as a storage material or as a permanent structural element, whose lifetime is regulated by an organic matrix. The relevance of ACC in materials science is primarily related to our understanding of CaCO3 crystallization pathways and CaCO3/(bio)polymer nanocomposites. ACC can be synthesized by liquid–liquid phase separation, and it is typically stabilized with macromolecules. We have prepared ACC by milling calcite in a planetary ball mill. Phosphate “impurities” were added in the form of monetite (CaHPO4) to substitute the carbonate anions, thereby stabilizing ACC by substitutional disorder. The phosphate anions do not simply replace the carbonate anions. They undergo shear-driven acid/base and condensation reactions, where stoichiometric (10%) phosphate contents are required for the amorphization to be complete. The phosphate anions generate a strained network that hinders ACC recrystallization kinetically. The amorphization reaction and the structure of BM-ACC were studied by quantitative Fourier transform infrared spectroscopy and solid state 31P, 13C, and 1H magic angle spinning nuclear magnetic resonance spectroscopy, which are highly sensitive to symmetry changes of the local environment. In the first—and fast—reaction step, the CO32– anions are protonated by the HPO42– groups. The formation of unprecedented hydrogen carbonate (HCO3–) and orthophosphate anions appears to be the driving force of the reaction, because the phosphate group has a higher Coulomb energy and the tetrahedral PO43– unit can fill space more efficiently. In a competing second—and slow—reaction step, pyrophosphate anions are formed in a condensation reaction. No pyrophosphates are formed at higher carbonate contents. High strain leads to such a large energy barrier that any reaction is suppressed. Our findings aid in the understanding of the mechanochemical amorphization of calcium carbonate and emphasize the effect of impurities for the stabilization of the amorphous phases in general. Our approach allowed the synthesis of new amorphous alkaline earth defect variants containing the unique HCO3– anion. Our approach outlines a general strategy to obtain new amorphous solids for a variety of carbonate/phosphate systems that offer promise as biomaterials for bone regeneration.
KW - Crystallization
KW - Mechanochemistry
KW - PDF
PY - 2020
DO - https://doi.org/10.1021/acs.cgd.0c00912
VL - 20
IS - 10
SP - 6831
EP - 6846
PB - American Chemical Society
AN - OPUS4-51819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chinnasamy, R.
A1 - Ravi, J.
A1 - Pradeep, V.V.
A1 - Manoharan, D.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Adaptable Optical Microwaveguides From Mechanically Flexible Crystalline Materials
N2 - Flexible organic crystals (elastic and plastic) are important materials for optical waveguides, tunable optoelectronic devices, and photonic integrated circuits. Here, we present highly elastic organic crystals of a Schiff base, 1-((E)-(2,5-dichlorophenylimino)methyl)naphthalen-2-ol (1), and an azine molecule, 2,4-dibromo-6-((E)-((E)-(2,6-dichlorobenzylidene)hydrazono)methyl)phenol (2). These microcrystals are highly flexible under external mechanical force, both in the macroscopic and the microscopic regimes. The mechanical flexibility of these crystals arises as a result of weak and dispersive C−H⋅⋅⋅Cl, Cl⋅⋅⋅Cl, Br⋅⋅⋅Br, and π⋅⋅⋅π stacking interactions. Singly and doubly-bent geometries were achieved from their straight shape by a micromechanical approach using the AFM cantilever tip. Crystals of molecules 1 and 2 display a bright-green and red fluorescence (FL), respectively, and selective reabsorption of a part of their FL band. Crystals 1 and 2 exhibit optical-path-dependent low loss emissions at the termini of crystal in their straight and even in extremely bent geometries. Interestingly, the excitation position-dependent optical modes appear in both linear and bent waveguides of crystals 1 and 2, confirming their light-trapping ability.
KW - Crystal growth
KW - Fluorescence
KW - Mechanophotonics
KW - Micromanipulation
KW - Optical waveguides
PY - 2022
DO - https://doi.org/10.1002/chem.202200905
SN - 0947-6539
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-55018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time resolved in situ monitoring of mechanochemical transformations by X-ray spectroscopy (XAS)
N2 - Mechanochemical reactions promise a new direction for environmentally benign preparation of materials, and has been dubbed by IUPAC as one of the 10 chemical innovations that will change our world. Despite this significant promise, very little is known about the mechanisms that drive mechanochemical transformations, posing significant barriers to realizing their full potential. To this end, there is growing need to follow mechanochemical reactions in situ and in real time. We here describe advances in the development and application of XAS methods to monitor material synthesis in real time under mechanochemical conditions. We demonstrate the generality of our approaches by describing mechanochemical syntheses of materials by both vibratory ball milling and by Resonant Acoustic Mixing (RAM), where a time resolution of 1 second is for a whole XAS spectrum was achieved. Moreover, we describe how spectroscopic methods can be coupled to diffraction-based approaches, thereby providing new dimensions in understanding mechanochemical synthesis.
T2 - Denver X-ray Conference: DXC 2021
CY - Online meeting
DA - 02.08.2021
KW - Dispersive XAS
KW - Mechanochemistry
KW - Time resolved
KW - In situ
PY - 2021
AN - OPUS4-56257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manoharan, Deepak
A1 - Ranjan, Subham
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Takamizawa, Satoshi
A1 - Ghosh, Soumyajit
T1 - Elasto-plastic behaviour with reversible thermosalient expansion in acrylonitrile-based organic crystals
N2 - Crystalline materials that exhibit reversible mechanical responses upon exposure to external stimuli have garnered significant attention owing to their potential applications in various fields. Herein, we report a crystal of (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(4-bromophenyl)acrylonitrile) (DSBr), which displays simultaneous elasto-plastic behaviour and reversible thermosalient effects. While elasto-plastic behaviour is attributed to underlying packing features, reversible thermosalient expansion is attributed to uniaxial expansion mediated by heat. Exceptional length increase and contraction upon cooling is due to the restorative nature of weak interactions through a cooperative effect. The cooperative movement of molecules is reflected in the unidirectional expansion of the habit plane. Thermosalient reversible expansion–contraction in elasto-plastic crystals have not been discussed in the literature so far. Detailed analysis reported herein provides a comprehensive understanding of the underlying mechanism of flexibility and thermosalient responses. This crystal's unique blend of reversible thermal expansion with flexibility holds substantial promise for applications in flexible thermal actuators.
KW - Materials Chemistry
KW - General Chemistry
PY - 2024
DO - https://doi.org/10.1039/D3TC04272C
SN - 2050-7526
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Validation of microplastics detection methods and proficiency testing: Suitable microplastic reference materials for interlaboratory comparison
N2 - The talk summarizes challenges in microplastic analysis. It shows the preparation of microplastic reference materials as well as the testing on homogeneity and stability. The reference material is used in an international laboratory comparison to compare different detection methods used for microplastic analysis. The methods used were µ-IR (FTIR+LDIR) for number-based methods and TED-GC/MS and Py-GC/MS for mass-based methods. The ILC was done under the umbrella of VAMAS TWA 45. Results of the participants are presented.
T2 - BAM Akademie
CY - Online meeting
DA - 16.05.2024
KW - Microplastics
KW - Reference materials
KW - ILC
KW - Microplastics detection
KW - TED-GC/MS
KW - Polymer 3R
PY - 2024
AN - OPUS4-60085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Mikroplastik Detektion mit Thermoanalytischen Methoden: Analytik, Referenzmaterial, Ringversuche
N2 - Ich dem Vortrag geht es um die Vorstellung von thermoanalytischen Methoden für die Mikroplastik-Detektion. Verschiedene Kopplungsmöglichkeiten werden gezeigt und die Funktionsweise der TED-GC/MS wird erklärt. Im zweiten Teil werden Referenzmaterialien für die Mikroplastik-Analytik diskutiert. PET -Tabletten des PlasticTrace Projektes werden vorgestellt. Am Ende wird der VAMAS Ringversuch zur Mikroplastik-Detektion gezeigt.
T2 - Plastik, Mikroplastik, Nanopartikel, PFAS und Verunreinigungen (Agilent Workshop)
CY - Hamburg, Germany
DA - 28.05.2024
KW - Mikroplastik
KW - TED-GC/MS
KW - Polymer 3R
KW - Ringversuche
KW - Referenzmaterial
PY - 2024
AN - OPUS4-60155
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Giovannozzi, A
T1 - Metrological traceability of measurement data from nano- to small microplastics for a greener environment and food safety
N2 - This talk descibes the EMPIR project PlasticTrace. Reference materials for microplastics will be developed. The production process and characterisation is explained by SEM, Raman, IR, Py-GC/MS and TED-GC/MS. Homogeneity control was successful. Stability check show no changes over 6 month.
T2 - SETAC Europe 2024
CY - Sevilla, Spain
DA - 05.05.2024
KW - Microplastics
KW - Reference materials
KW - Polymer 3R
KW - TED-GC/MS
PY - 2024
AN - OPUS4-60033
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - Revealing surface functionalities of micro- and nanoplastic particles’ surface by means of XPS
N2 - Over the last 20 years, many researchers, politicians, and citizens themselves have become increasingly aware of the growing plastic problem of our time. Inadequate recycling concepts, collection points, and careless dumping of plastic products in the environment lead to an accumulation of plastic. External weather influences can cause these to degrade and fractionate, so that today microplastics (1-1000 µm, ISO/TR 21960:2020) [1] of different polymer materials can be detected in all parts of the world.
The precautionary principle applies to microplastics. The particles can break down further to form nanoplastics (<1 µm, ISO/TR 21960:2020) [1]. Whether microplastics or nanoplastics pose a toxicological hazard is being investigated in a variety of ways. Valid results are still pending, however, investigations into the frequency, transport, possible sinks and entry paths must be taken into account. This is why monitoring of microplastics is already required in the revision of the Drinking Water Framework Directive [2]. The same is still pending in the final version of the revision of the Waste Water Framework Directive this year, but is expected.
Nanoplastics are particularly under discussion for having a toxic effect on humans and animals, as these particles are small enough to be absorbed by cells. For targeted toxicological studies, it is important to have test and reference materials that resemble the particles found in the environment. To mimic environmental samples, these materials should also have an irregular shape and show aging at the surface, which can be detected with XPS or SEM/EDS.
BAM in collaboration with the EMPIR project "PlasticTrace" works on a reference material candidate of nano-sized polypropylene (nano-PP) [3]. The nano-PP vials were tested for homogeneity with PTA and further characterized with bulk and surface-sensitive techniques. An SEM image and a corresponding XPS spectrum are presented in Figure 1. Raman measurements as well as XPS indicate an aged surface.
T2 - ECASIA 2024
CY - Gothenburg, Sweden
DA - 09.06.2024
KW - Surface chemistry
KW - Micro- and nanoplastics
KW - X-ray Photoelectron Spectroscopy
KW - MNP production technique
PY - 2024
AN - OPUS4-60535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Interlaboratory comparisons for obtaining reliable data on microplastic detection methods
N2 - Since microplastics (MPs) can be found everywhere and are becoming a problem of high concern, it is necessary to understand their occurrence and fate in the environment. However, to obtain data of high quality is very challenging, since measurement operating procedures differ from laboratory to laboratory. Currently, there are no standardized methods to analyze microplastics. One promissing possibility to adress standardization of the methodology and operating procedures are interlaboratory comparisons (ILCs). In this contribution we report the first results of an ILC on microplastic detection methods organized under the pre-stantdardisation plattform of VAMAS (www.vamas.org/twa45/) as Project 2 “Development of standardized methodologies for characterisation of microplastics with microscopy and spectroscopy methods”, within the Technical Working Area TWA 45 “Micro and Nano Plastics in the Environment”. The ILC has gathered 84 participants all over the world representing all continents. BAM, as the project leader, produced a set of reference microplastic materials, which have been distributed to all the participants together with the measurement protocols and reporting data templates.
T2 - SETAC 34th Meeting
CY - Seville, Spain
DA - 05.05.2024
KW - ILC
KW - Microplastic
KW - Py-GC/MS
KW - Polyethylene
KW - µ-Raman
KW - µ-FTIR
KW - Polyethylene Terephtalate
KW - TED-GC/MS
PY - 2024
AN - OPUS4-60038
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Drago, C.
T1 - Standardization Methods for the Analysis of Microplastics (10 100µm) in Food Matrix: Sample Preparation and Digestion of Milk Powder.
N2 - Monitoring of microplastics in food matrices is crucial to determinate the human exposure. By direct ingestion microplastics could be released in the food during the production, through packaging and by consumer’s use. The absence of standard methods to quantify and detect different size range and type of microplastics has led to difficult and time consuming procedural steps, poor accuracy and lack of comparability. In this work, matrix characterization and laboratory experiments were used to investigate the efficiency of sample preparation in milk powder. This information is crucial to compile a standard procedure for sample preparation and digestion of common milk powder to detect different particle sizes and types of polymers. Charaterisation is done by TGA and TOC measurements.
T2 - SETAC Europe 2024
CY - Sevilla, Spain
DA - 05.05.2024
KW - Microplastics
KW - Harmonisation in microplastics
KW - Polymer 3R
KW - Microplastics in milk
PY - 2024
AN - OPUS4-60034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - An Amorphous Lewis-acidic Zirconium Chlorofluoride as HF Shuttle: C-F Bond Activation and Formation
N2 - In recent years, fluorine chemistry has gained increasing political attention. Owing to a growing shortage of fluorspar, a raw material used for producing fluorinated base chemicals, fluorospar has been named among the 30 critical raw materials in the EU.2 As such, it becomes increasingly important to recycle existing fluorinated compounds and make them available as sources of fluorine for reactions. Significant progress has been made in the field of C-F bond activation using heterogeneous catalysts such as aluminum chlorofluoride (ACF).3–5 However, the transfer of fluorine atoms from one molecule to another using heterogeneous catalysts has not yet been reported. In this study, we successfully synthesized amorphous zirconium chlorofluoride (ZCF), and we were able to establish a catalytic behavior of ZCF in C-F bond activation reactions. We present a heterogeneous catalyst that performs dehydrofluorination of a fluoroalkane and consecutive hydrofluorination of an alkyne at room temperature.
T2 - 2nd South African Fluorine Symposium
CY - Sun City, South Africa
DA - 09.02.2024
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - HF-shuttle
PY - 2024
AN - OPUS4-59618
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heinekamp, Christian
T1 - A fluorolytic sol-gel route to access an amorphous Lewis-acidic Zr fluoride catalyst
N2 - Kemnitz et al. developed a fluorolytic route to access metal fluorides 2 such as AlF3 3 and MgF2 4 which possess a high surface area. In aluminium-based systems, the synthetic approach led to amorphous xerogels that can be further converted into Lewis superacids.3 Still, despite zirconium oxide being described as a stronger Lewis acid than other metal oxides 4 zirconium fluoride-based materials have only recently been reported or investigated. 6 In this work we extend the class of amorphous Lewis acidic heterogeneous catalysts to an amorphous ZrF4 that is active in C-F bond activation.
T2 - 2nd South African Fluorine Symposium
CY - Sun City, South Africa
DA - 11.02.2024
KW - ZrF4
KW - Heterogeneous catalysis
KW - C-F bond activation
PY - 2024
AN - OPUS4-59617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mojsak, Mateusz
A1 - Bodo, Filippo
A1 - Erba, Alessandro
A1 - Michalchuk, Adam A. L.
A1 - Kraka, Elfi
T1 - Local Vibrational Mode Analysis of Phonon Dispersion Relations in Crystals
N2 - We present a general framework for performing local vibrational mode analysis of vibrations in crystalline materials at arbitrary wavevectors throughout the Brillouin zone. The approach enables phonon dispersion relations to be interpreted in terms of chemically meaningful interatomic interactions and structural motifs, providing direct insight into the microscopic origins of the phonon behavior in periodic systems. We demonstrate the methodology for representative one-, two-, and three-dimensional materials including polymeric chains, graphene, and prototypical rock-salt and perovskite crystals. Across these systems, the analysis reveals how specific bonding patterns and structural features govern phonon dispersion relations. This framework provides a quantitative tool for the chemically intuitive analysis of phonon spectra and offers a pathway toward the rational design of phonon-dependent properties in crystalline materials.
KW - Phonons
KW - Molecular Crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656430
DO - https://doi.org/10.1021/acs.jctc.6c00097
SN - 1549-9618
SP - 1
EP - 16
PB - American Chemical Society (ACS)
AN - OPUS4-65643
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Mrkwitschka, Paul
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - XPS/HAXPES and EDS spectra with ROI
N2 - XPS/HAXPES spectra as well as EDS spectra and SEM micrographs with regions of interest. Measurement scheme included as a powerpoint presentation.
Investigated materials: Ionic liquid and commercial and lab-synthesized graphene oxide.
KW - EDX
KW - XPS
KW - Graphene Oxide
KW - Ionic Liquid
PY - 2026
DO - https://doi.org/10.5281/zenodo.18231732
PB - Zenodo
CY - Geneva
AN - OPUS4-65624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez‐Sánchez, Noelia
A1 - Ballesteros, Menta
A1 - Prinz, Carsten
A1 - Canosa, Inés
A1 - Flores Díaz, Amando
A1 - Bhattacharya, Biswajit
A1 - Ruiz‐Salvador, A. Rabdel
A1 - Emmerling, Franziska
T1 - Mechanochemical Fullerene Nanoencapsulation in Amino‐Functionalized ZIF‐12 for Visible‐Light Disinfection of Waterborne Viruses and Bacteria
N2 - Water contamination poses a significant threat to public health and environmental sustainability, necessitating the development of efficient purification technologies. This study reports the mechanochemical synthesis of an amino-functionalized ZIF 12 framework with encapsulated fullerene (C60) as a bifunctional photocatalyst for water decontamination and disinfection under visible-light irradiation. The samples were characterized using powder X-ray diffraction (PXRD), FT-IR spectroscopy, N2 adsorption isotherm, X-ray photoelectron spectroscopy (XPS), electron microscopy (SEM and TEM), thermogravimetric Analysis (TGA), and UV–vis diffuse reflectance spectroscopy (DRS), confirming the retention of crystallinity and effective incorporation of C60 and amino groups within the framework. Fullerene loading and amino functionalization modified the optical properties, extending visible light absorption and enhancing charge separation and photocatalytic activity. The synergistic interaction between amino groups and C60 promotes efficient charge separation and enhanced hydroxyl radical production, resulting in improved photocatalytic and photo-Fenton activity. C60@ZIF-12-NH2 exhibited excellent photocatalytic performance, achieving the completeinactivation of bacteriophage P22 under saline conditions and effective disinfection of E.coli and coliforms innatural river water, demonstrating robustness under environmentally relevant conditions. The solvent-minimized mechanochemical synthesis and visible-light-driven activity position the C60@ZIF-12-NH2 composite as a promising platform for sustainable and advanced water treatment applications.
KW - Fullerene
KW - Heterogeneous photo-Fenton
KW - Mechanochemistry
KW - Nanoencapsulation
KW - Photocatalysis
KW - ZIF-12
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656531
DO - https://doi.org/10.1002/smll.202512881
SN - 1613-6810
SP - 1
EP - 19
PB - Wiley-VCH GmbH
AN - OPUS4-65653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belenguer, A
A1 - Michalchuk, Adam
A1 - Lampronti, G
A1 - Sanders, J
T1 - Using solid catalysts in disulfide-based dynamic combinatorial solution- and mechano-chemistry
N2 - We here show for the first time that solid amines can act as catalysts for disulfide-based dynamic combinatorial chemistry by ball mill grinding. The mechanochemical Equilibrium for the two disulfide reactions studied is reached within one to three hours using ten different amine catalysts. This contrasts with the weeks to months to achieve solution equilibrium for most solid amine catalysts at 2%M at 2mM concentration in a suitable solvent. The final mechanochemical equilibrium is independent of the catalyst used, but varies with other ball mill grinding factors such as the presence of traces of solvent. The different efficiencies of the amines tested are discussed.
KW - Mechanochemistry
KW - Green chemistry
KW - Catalysis
PY - 2022
DO - https://doi.org/10.1002/cssc.202102416
SN - 1864-5631
VL - 15
IS - 3
SP - 1
EP - 10
PB - Wiley
AN - OPUS4-53930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - McMonagle, C. J.
A1 - Michalchuk, Adam
A1 - Chernyshov, D.
T1 - FOX-7 high-energy-density material: Thermal expansion and phase transitions revisited
N2 - Variable-temperature single-crystal diffraction experiments treated with the Gandolfi method reveal the detailed temperature evolution of the unit-cell dimensions, structural transformations and the phase co-existence of the energetic material FOX-7. Two first-order phase transitions are observed accompanied by abrupt changes in volume and unit-cell dimensions. The thermal expansion is found to be linear for all three phases, albeit highly anisotropic. Moreover, the experimental thermal expansion coefficients differ from those predicted from literature atomistic simulations.
KW - Energetic materials
KW - Thermal expansion
KW - Gandolfi method
KW - Phase transition
KW - Variable temperature
PY - 2022
DO - https://doi.org/10.1107/S2052520621013299
SN - 2052-5206
VL - 78
IS - 1
SP - 91
EP - 95
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-54286
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Shaken not stirred: enhancing the flavor of mechanochemistry
N2 - Mechanochemistry is increasingly used for synthesizing soft matter materials including metal organic compounds and cocrystals.1 The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Time-resolved in situ investigations of milling reactions provide direct insights in the underlying mechanisms.2-4 We recently introduced different setups enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy and thermography. The presented setup allows the detection of crystalline, amorphous, eutectic, and liquid intermediates. Furthermore, the chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key for future optimization of mechanochemical syntheses. In this contribution, we will discuss our recent results investigating the formation of (polymorphic) cocrystals and coordination polymers.2,3,5 Our results indicate that in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical syntheses.
T2 - BCA/BACG joint spring meeting
CY - Online meeting
DA - 29.03.2021
KW - Mechanochemistry
KW - Cocrystals
KW - Crystal Engineering
PY - 2021
AN - OPUS4-53995
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yusenko, Kirill
A1 - Emmerling, Franziska
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - X-Ray absorption spectroscopy to study multicomponent materials
N2 - Detailed study of multicomponent systems in solid-state as well as in solution using X-ray diffraction and X-ray spectroscopy is one of the most common topics in modern materials chemistry. 5-6 component high-entropy alloys such as fcc- and bcc-structured AlxCoCrFeNi and fluorescent nanoparticles based on fluorite-structured SrF2 doped by rare-earth metals in organic solutions have high complexity and their local structure cannot be resolved using only diffraction. X-ray absorption spectroscopy should be applied to understand peculiarities in their local structure and make a link between structure on short and long ranges and their macroscopic properties. Here, based on two representativee examples, we discuss how a combination of several X-ray absorption edges might give new insights into complex materials.
T2 - Virtual meeting of the African Light Source
CY - Online meeting
DA - 15.11.2021
KW - EXAFS
KW - Synchrotron studies
PY - 2021
AN - OPUS4-54014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Shaken not stirred: in situ investigations of mechanochemical processes
N2 - Mechanochemistry has emerged as one of the most interesting synthetic protocols to produce new materials. The development of mechanochemistry as a synthetic method is supported by excellent research by many groups worldwide in a wide range of applications. The potential of mechanochemistry is also reflected in the inclusion in IUPAC’s 10 chemical innovations that will change our world’.[1] Solvent-free methodologies lead to unique chemical processes during synthesis with the consequent formation of martials with new properties.2 In this contribution, we will discuss our recent results investigating the formation of (polymorphic) cocrystals, coordination polymers, metal oxides and metal nanoparticles.[3-8] We introduced different setups enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy and thermography.
T2 - Deutsche Kristallzüchtertagung
CY - Berlin, Germany
DA - 06.10.2021
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Crystal
PY - 2021
AN - OPUS4-53996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Scientific Writing - best practice tools
N2 - Personal view of an experienced writer on how to write a paper.
T2 - MatchingCamp 2021
CY - Bad Belzig, Germany
DA - 08.11.2021
KW - Writing
PY - 2021
AN - OPUS4-53999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
A1 - Ciornii, Dmitri
A1 - Hodoroaba, Vasile-Dan
A1 - Braun, U.
T1 - Requirements for inter-lab comparison studies and cooperation with CUSP and JRC
N2 - Results from different methods applied to micro- and nanoplastics (MNPs) analysis show that there are large gaps in harmonisation with respect to terminology, size classes, sample preparation protocols and, finally, to the comparability of the measurands and descriptors.
Within the European research cluster to understand the health impacts of micro- and nanoplastics (CUSP) working group WG3-Inter-Laboratory Comparisons an overview of the existing detection methods revealing advantages and disadvantages regarding the analytical tasks is being compiled. There is a clear need to develop high class characterized reference materials for MNPs in the size ranges of 100-10 µm and smaller than 10 µm, so that these can be used to validate methods and to make results comparable. Inter-laboratory comparisons (ILCs) on model samples with complex matrices regarding mass, or water samples for number-based methods, will help us to advance the process of harmonization as well as to train users early in process of developing new methods.
We plan to keep all five CUSP projects well-connected also with the 'outside' MNP projects and ILCs and to extract the optimum of needs, capabilities, and efforts in order to launch new VAMAS ILCs which should expand already available ones.
T2 - CUSP Meeting and General Assembly of PlasticsFatE
CY - Online meeting
DA - 13.12.2021
KW - CUSP
KW - Microplastic
KW - Inter-lab comparison
KW - VAMAS
KW - Reference materials
PY - 2021
UR - https://cusp-research.eu/about/
AN - OPUS4-54036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feiler, Torvid
T1 - Polymorphic tuning of a flexible organic crystal optical waveguide
N2 - Crystalline molecular materials are usually brittle and are prone to break upon external mechanical force. This fragility poses challenges for their application in next-generation technologies, including sensors, synthetic tissues, and advanced opto-electronics. The recent discovery of mechanical flexibility in single crystals of molecular materials has solved this problem and enable the design of smart flexible device technologies. Mechanical flexibility of organic crystals can be tuned by altering the weak interactions in the crystal structure, for examples through polymorphism. Here we report 4-bromo-6-[(6-chlorolpyridin-2-ylimino)methyl]phenol (BCMPMP) as a promising candidate for future waveguide technologies. It turns out that BCMPMP has two different polymorphs with distinct optical and mechanical properties. Form I shows brittle behavior under mechanical stress and exhibits very weak emission at 605 nm (λex = 425 nm) together with a low fluorescence quantum yield (Φ = 0.4 %).In contrast, Form II has a large plastic (irreversible bending) regime and a bright emission at 585 nm (λex = 425 nm; Φ = 8.7 %). Making use of favorable mechanical fexiblity and optical properties, form II was explored as a bendable optical waveguide. Light was successfully propagated through a straight-shaped and mechanically deformed BCMPMP crystal. Depending on the light source, active or passive waveguiding could be achieved. So BCMPMP can also be used as a flexible wavelength filter.
T2 - Congress of the International Union of Crystallography - IUCr 2021
CY - Online meeting
DA - 14.08.2021
KW - Flexible crystals
KW - Polymorphism
KW - Waveguide
PY - 2021
AN - OPUS4-53906
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feiler, Torvid
A1 - Bhattacharya, Biswajit
T1 - Mechanically flexible crystals: materials for new generation of responsive materials
N2 - Based on the nature of the deformation, molecular crystals can be defined as being plastically (irreversible) or elastically (reversible)bendable. The mechanical response of crystals is thereby directly related to they structure.The structural elements required for a specific mechanical behavior are known, so that compounds with these properties can be synthesized by applying the rules of crystal engineering.
T2 - Berlin Science Week
CY - Berlin, Germany
DA - 01.11.2021
KW - Flexible crystals
PY - 2021
AN - OPUS4-53907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Update – Milling and weathering of granules
N2 - The talk aims to describe the production of microplastic particles as test material and the additional weathering for aged particles.
T2 - PlasticsFate meeting
CY - Online meeting
DA - 12.11.2021
KW - Microplastic
KW - Cryo milling
KW - Aged particles
PY - 2021
AN - OPUS4-53737
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Martins, Ines
T1 - Carbamazepine Dihydroxybenzoic Acid Cocrystals: Exploring Packing Interactions and Reaction Kinetics
N2 - Herein, we present the mechanochemical formation of three new cocrystals containing the active pharmaceutical ingredient carbamazepine and dihydroxybenzoic acids as coformers (CBZ:2,4-DHBA 1:1, CBZ:2,5-DHBA 1:1, and CBZ:2,6-DHBA 1:1). Rietveld methods were used for three different purposes: (i) refining all structures solved using powder X-ray diffraction, (ii) performing a quantitative phase analysis of the diffraction data collected from ex situ mechanochemical reactions at different milling times, and (iii) determining the cocrystallization kinetic profiles. The rate of cocrystallization was found to be higher for the formation of CBZ:2,4-DHBA and CBZ:2,6-DHBA, reaching an equilibrium after 600 s of milling. In the case of CBZ:2,5-DHBA a short induction period of 20 s was detected prior to the start of the reaction and an equilibrium was reached after 1200 s. An empirical trend between the rate of cocrystallization and the structural complexity of the cocrystal product was found. The slowest cocrystallization rate observed for CBZ:2,5-DHBA corresponds to the crystal structure deviating substantially from the hydrogen-bonding motif found in the reactants.
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - Kinetics
PY - 2021
DO - https://doi.org/10.1021/acs.cgd.1c00902
VL - 21
IS - 12
SP - 6961
EP - 6970
PB - ACS Publications
AN - OPUS4-54407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kosareva, E.
A1 - Gainutdinov, R.
A1 - Michalchuk, Adam
A1 - Ananyev, I.
A1 - Muravyev, N.
T1 - Mechanical Stimulation of Energetic Materials at the Nanoscale
N2 - The initiation of energetic materials by mechanical stimuli is a critical stage of their functioning, but remains poorly understood. Using atomic force microscopy (AFM) we explore the microscopic initiation behavior of four prototypical energetic materials: 3,4-dinitropyrazole, 𝜖-CL-20, 𝛼-PETN and picric acid. Along with the various chemical structures, these energetic compounds cover a range of application types: a promising melt-cast explosive, the most powerful energetic compound in use, a widespread primary explosive, and a well-established nitroaromatic explosive from the early development of energetics. For the softest materials (picric acid and 3,4-dinitropyrazole), the surfaces were found to behave dynamically, quickly rearranging in response to mechanical deformation. The pit created by nanoscale friction stimulation on the surface of 3,4-dinitropyrazole doubled in volume upon aging for half an hour. Over the same time frame, a similar pit on picric acid surface increased in volume by more than seven-fold. Remarkably, increased humidity was found to reduce the rate of surface rearrangement, potentially offering an origin for the desensitization of energetic materials when wetted. Finally, we identify an inverse correlation between the surface dynamics and mechanical sensitivity of our test energetic compounds. This strongly suggests that surface dynamics influence a material’s ability to dissipate excess energy, acting as a buffer towards mechanical initiation.
KW - Energetic materials
KW - Mechanical Properties
KW - Mechanical Sensitivity
PY - 2022
DO - https://doi.org/10.1039/D2CP00832G
VL - 24
IS - 15
SP - 8890
EP - 8900
PB - Royal Society of Chemistry
AN - OPUS4-54562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Tothadi, S.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Different mechanical responses of dimorphic forms of Anthracene Schiffbase crystal
N2 - We obtained concomitant dimorphic forms of Anthracene Schiffbase (N-(anthracen-9-yl methylene)-2,5- dichloroaniline) from hexane solvent. Two polymorphs can be differentiated by their morphology and mechanical properties. One form is long acicular type and elastically bendable while another form is block shaped and brittle in nature. Mechanical property is attributed to underlying crystal packing. Hirsh- feld analysis and energy framework calculations were done to corroborate structure-property correlation of two forms.
KW - Elasticity
KW - Mechanical properties
KW - Anthracene schiff base
KW - Dimorphs
PY - 2021
DO - https://doi.org/10.1016/j.molstruc.2021.132182
VL - 1252
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-54356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Casali, C.
A1 - Feiler, Torvid
A1 - Heilmann, Maria
A1 - Braga, D.
A1 - Emmerling, Franziska
A1 - Grepioni, F.
T1 - Too much water? Not enough? In situ monitoring of the mechanochemical reaction of copper salts with dicyandiamide
N2 - n situ monitoring of mechanochemical reactions between dicyandiamide (DCD) and CuX2 salts (X = Cl−, NO3−), for the preparation of compounds of agrochemical interest, showed the appearance of a number of phases. It is demonstrated that milling conditions, such as the amount of water added in wet grinding and/or the milling frequency, may affect the course of the mechanochemical reactions, and drive the reaction towards the formation of different products. It has been possible to discover by in situ monitored experiments two novel crystalline forms, namely the neutral complexes [Cu(DCD)2(OH2)2(NO3)2] (2) and [Cu(DCD)2(OH2)Cl2]·H2O (4), in addition to the previously known molecular salt [Cu(DCD)2(OH2)2][NO3]2·2H2O (1, DIVWAG) and neutral complex [Cu(DCD)2(OH2)Cl2] (3, AQCYCU), for which no synthesis conditions were available. Compounds 2 and 4 were fully characterized via a combination of solid-state techniques, including X-ray diffraction, Raman spectroscopy and TGA.
KW - Mechanochemistry
KW - In situ
PY - 2022
DO - https://doi.org/10.1039/d1ce01670a
VL - 24
IS - 6
SP - 1292
EP - 1298
PB - RSC
AN - OPUS4-54344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Plastik in Böden: Mikroplastik-Analytik
N2 - Im Vortrag wir eine Methode zur Analyse von Mikroplastik in Böden dargestellt. Es geht dabei um die Probenvorbereitung und Detektion.
T2 - Fachgespräch "Plastik in Böden"
CY - Online meeting
DA - 28.03.2022
KW - Mikroplastik
KW - TED-GC/MS
KW - Mikroplastik-Analytik
KW - Methodenentwicklung Böden
PY - 2022
AN - OPUS4-54646
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feiler, Torvid
T1 - Mechanically plastic molecular crystals for shapeable optic waveguides
N2 - Molecular crystalline materials are usually brittle and are prone to breaking when mechanically stressed. This fragility greatly limits they application in next the generation of adaptable, functional materials. The recent discovery of mechanical compliancy in molecular crystals has solved this problem.1 Based on the nature of the deformation, molecular crystals can be divided into being plastically (irreversibly) or elastically (reversibly) bendable. The plastic deformation is generally associated with anisotropic molecular arrangements and the existence of low energy slip planes which allow a permanent motion within the lattice. Here we report 4-bromo-6-[(6-chloropyridin-2-ylimino)methyl]phenol (CPMBP) as a promising candidate for future waveguide technologies.2 CPMBP has been found to have two different polymorphs with distinct optical and mechanical properties. The brittle crystals of Form I exhibits very weak emission at 605 nm (λex = 425 nm; photoluminescence quantum yield Φ = 0.4 %). In contrast, Form II has a large plastic regime together with a bright emission at 585 nm (λex = 425 nm; Φ = 8.7 %). Taking advantage of the favorable mechanical flexibility and optical properties, Form II was used as a shapeable optical waveguide. By changing the wavelength of the light source, active or passive waveguiding can be realized. CPMBP could thus be used as a flexible wavelength filter.
T2 - 30. Jahrestagung der Deutschen Gesellschaft für Kristallographie
CY - Online meeting
DA - 14.3.2022
KW - Flexible crystals
KW - Polymorphism
KW - Waveguide
PY - 2022
AN - OPUS4-54514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Plastik in Böden: Mikroplastik-Ergebnisse
N2 - In diesem Vortrag geht um die Vorstellung der Ergebnisse des UBA Projektes Plastik in Böden. Es werden Mikroplastik-Gehalte in verschiedenen Böden präsentiert.
T2 - Fachgespräch "Plastik in Böden"
CY - Online meeting
DA - 28.03.2022
KW - Mikroplastik
KW - Mikroplastik Böden
KW - Mikroplastik-Analytik
PY - 2022
AN - OPUS4-54648
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feiler, Torvid
T1 - Mechanically plastic molecular crystals for shapeable optic waveguides
N2 - Molecular crystalline materials are usually brittle and are prone to breaking when mechanically stressed. This fragility greatly limits they application in next the generation of adaptable, functional materials. The recent discovery of mechanical compliancy in molecular crystals has solved this problem.1 Based on the nature of the deformation, molecular crystals can be divided into being plastically (irreversibly) or elastically (reversibly) bendable. The plastic deformation is generally associated with anisotropic molecular arrangements and the existence of low energy slip planes which allow a permanent motion within the lattice. Here we report 4-bromo-6-[(6-chloropyridin-2-ylimino)methyl]phenol (CPMBP) as a promising candidate for future waveguide technologies.2 CPMBP has been found to have two different polymorphs with distinct optical and mechanical properties. The brittle crystals of Form I exhibits very weak emission at 605 nm (λex = 425 nm; photoluminescence quantum yield Φ = 0.4 %). In contrast, Form II has a large plastic regime together with a bright emission at 585 nm (λex = 425 nm; Φ = 8.7 %). Taking advantage of the favorable mechanical flexibility and optical properties, Form II was used as a shapeable optical waveguide. By changing the wavelength of the light source, active or passive waveguiding can be realized. CPMBP could thus be used as a flexible wavelength filter.
T2 - 30. Jahrestagung der Deutschen Gesellschaft für Kristallographie
CY - Online meeting
DA - 14.3.2022
KW - Flexible crystals
KW - Polymorphism
KW - Waveguide
PY - 2022
AN - OPUS4-54515
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aree, T.
A1 - McMonagle, C. J.
A1 - Michalchuk, Adam
A1 - Chernyshov, D.
T1 - Low-frequency lattice vibrations from atomic displacement parameters of a-FOX-7, a high energy density material
N2 - Highly anharmonic thermal vibrations may serve as a source of structural instabilities resulting in phase transitions, chemical reactions and even the mechanical disintegration of a material. Ab initio calculations model thermal motion within a harmonic or sometimes quasi-harmonic approximation and must be complimented by experimental data on temperature-dependent vibrational frequencies. Here multi-temperature atomic displacement parameters (ADPs), derived from a single-crystal synchrotron diffraction experiment, are used to characterize low-frequency lattice vibrations in the alpha-FOX-7 layered structure. It is shown that despite the limited quality of the data, the extracted frequencies are reasonably close to those derived from inelastic scattering, Raman measurements and density functional theory (DFT) calculations. Vibrational anharmonicity is parameterized by the Grüneisen parameters, which are found to be very different for in-layer and out-of-layer vibrations.
KW - Energetic Materials
KW - DFT
KW - Structural dynamics
KW - X-ray diffraction
PY - 2022
DO - https://doi.org/10.1107/S2052520622002700
SN - 2052-5206
VL - 78
SP - 376
EP - 384
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-54832
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Morrison, C.
T1 - From lattice vibrations to molecular dissociation
N2 - The ease with which an energetic material can be initiated by mechanical impact is a critical parameter directing material safety and application. While impact sensitivity metrics are traditionally derived experimentally, recent developments have highlighted that the phenomenon is amenable to first principles simulation. In this chapter, we will outline a fully ab initio approach to predict the relative impact sensitivities of energetic materials based on the mechanochemical principles that link the impact event to vibrational energy transfer.
This mechanism is key to rationalizing how a mechanical impact—which deposits energy into the low-frequency lattice vibrations—results in a molecular response. By simulating the vibrational energy levels (the so-called phonon density of states, PDOS) using first-principles computational methods (typically dispersion-corrected plane-wave density functional theory, PW-DFT) we can calculate the relative rate of energy propagation from the delocalized low-energy lattice vibrations through to the localized molecular modes. The latter traps the energy, which eventually results in bond rupture through heightened vibrational excitation.
This method, based on vibrational up-pumping, offers a route toward predicting the impact sensitivities of a broad range of energetic materials, provided the crystal structure of the compound (or salt or co-crystal) is known. While it does not offer insight into the sensitizing roles undoubtedly played by crystal defects or grain boundaries, it does provide a level of understanding at the molecular and crystal packing levels. Correspondingly, this approach offers a feedback mechanism to chemists and materials scientists to guide the design of new materials with desired impact sensitivity behavior.
KW - Energetic materials
KW - Density functional theory
KW - Material design
PY - 2022
DO - https://doi.org/10.1016/B978-0-12-822971-2.00010-3
VL - 22
SP - 215
EP - 232
PB - Elsevier B.V.
AN - OPUS4-54717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Smart Machines, New Materials, Automated Future
N2 - In pursuing the automated synthesis of metal nanoparticles (NPs), the capabilities of the “Chemputer” are deployed, for the first time, into the field of inorganic chemistry. Metal NPs have a substantial impact across different fields of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver NPs are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize Ag NPs often do not result in well-defined products, the main obstacles being high polydispersity or a lack of particle size tunability.
The Chemputer is a modular, automated platform developed by the Cronin group for execution of multi-step, solution based organic synthesis. The machine has been further implemented at BAM, where we used this setup to perform automated organic syntheses, autonomously controlled by feedback derived from online NMR. In the Chemputer liquids can be transferred across a backbone, constructed from HPLC selection valves and syringe pumps. The Chemputer operates in a batch mode, common laboratory devices, such as heaters and glassware like round bottom flasks, are connected to the backbone, forming reaction modules. Solutions can be manipulated in these modules, and as all operations are controlled through a software script, reproducibility among individual syntheses is high. Likewise, any adjustments of the synthesis conditions, if required, are straightforward to implement and are documented in the reaction log file and a code versioning system.
We characterised Chemputer-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties. The approach is an important first step towards the automation of nanoparticle syntheses in a modular, multipurpose platform. The modularity of the Chemputer opens many possibilities for the synthesis of a variety of different NP morphologies and sizes and potentially more complex structures. These advances and further work can help in the general investigations of silver nanoparticles by supplying a reliable and reproducible method of their synthesis and removing tacit knowledge by significantly reducing the experimental bias.
T2 - Analytica 2022
CY - Munich, Germany
DA - 21.06.2022
KW - Automated synthesis
KW - Nanoparticles
PY - 2022
AN - OPUS4-55198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
T1 - Crystallization study of transition metal phosphates: A novel example for non-classical crystallization theory
N2 - Industrial and agricultural waste streams (waste waters, sludges, tailings etc.) which contain high concentrations of NH4+, PO43- and transition metals are environmentally harmful and toxic pollutants . Typically, separate pathways have been considered to extract hazardous and transition metals or phosphate as critical raw materials, independently from each other. Here, we report the synthesis routes for transition metal phosphate (TMP) compounds (M3(PO4)2∙8H2O, NH4MPO4∙6H2O, M = Ni2+, Co2+, M-struvite and M-phosphate octahydrate), which allow for P, ammonia and metal co-precipitation. The precipitation of these compounds from industrial and agricultural waste waters could be a promising P-recovery route. Through adjusting the reaction conditions, the stability, crystallite size and morphology of the as-obtained TMP could be controlled. Detailed investigations of the precipitation process using ex- and in-situ techniques provided new insights into their non-classical crystallization mechanism/crystal engineering of these materials. These TMPs involve transitional colloidal nanophases which subsequently aggregate and condense to final crystals after extended reaction times. However, the reaction kinetics of the formation of a final crystalline product vary significantly depending on the metal cation(s) involved in the precipitation process. The occurring amorphous nanophases seem to majorly influence the outcome of crystallization. Ni-struvite is stable in a wide reactant concentration range and at different metal/phosphorus (M/P)-ratios, whereas Co tends to form Co-struvite and/or Co-phosphate octahydrate depending on the (M/P)-ratio. The observed various degree of stability could be linked to the octahedral metal coordination environment. The achieved level of control over the precipitates, is highly desirable for 3d- and P-recovery methods. Under this paradigm, the crystals can be potentially upcycled as precursor materials for (electro)catalytical applications 4.
T2 - GeoMin Köln Konferenz 2022
CY - Cologne, Germany
DA - 11.09.2022
KW - Non-classical crystallization theory
KW - Amorphous phases
KW - Transition metal
KW - Phosphates
KW - Diffraction
PY - 2022
UR - https://www.geominkoeln2022.de/programme.html
AN - OPUS4-55874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Materials
N2 - The talk is a summary of materials and challenges recognized in the CUSP Cluster.
T2 - CUSP Annual Meeting at JRC (ISPRA)
CY - Ispra, Italy
DA - 08.06.2022
KW - Microplastic
KW - CUSP
KW - H2020
PY - 2022
AN - OPUS4-55099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - In-situ analysis of nucleation processes – case study: calciumsulfate
N2 - In this project we investigate nucleation pathways by utilizing synchrotron-XRD and running a case-study on calcium sulfate and its polymorphs. To accomplish this, we developed a modular automation setup for reactions in solution to run synthesis and control reaction conditions. So far we successfully characterized the recycling process of gypsum (CaSO4*2H2O) and are now investigating the formation of anhydrite (CaSO4*0H2O) as well as possible applications for the automation setup and analysis.
T2 - SALSA Make & Measure 2025
CY - Berlin, Germany
DA - 10.09.2025
KW - Recycling
KW - Gypsum
KW - Synchrotron-X-ray-diffraction
KW - Raman-spectroscopy
KW - Automation
PY - 2025
AN - OPUS4-64138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Wolf, Jako
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
T1 - SI Files for "Towards automation of the polyol process for the synthesis of silver nanoparticles"
N2 - The graphml file: reaction_graph_AgNP.graphml is included. It contains topological information (Fig. 1 in the main text) about the reaction setup and metadata with reaction condtions. It used by the Python API used to control the Chemputer.
SAXS reports. The complete report sheets generated by McSAS are included. They contain extended information characterising the size distributions and the fitting parameters.
NP3_I: saxs_report_NP3_I.pdf
NP3_II: saxs_report_NP3_II.pdf
NP3_III: saxs_report_NP3_III.pdf
NP3_IV: saxs_report_NP3_IV.pdf
NP5_I: saxs_report_NP5_I.pdf
NP5_II: saxs_report_NP5_II.pdf
NP5_III: saxs_report_NP5_III.pdf
KW - Automated synthesis
KW - Silver
KW - Nanoparticles
PY - 2022
DO - https://doi.org/10.5281/zenodo.5910614
PB - Zenodo
CY - Geneva
AN - OPUS4-55197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kenges, Kairat
A1 - Karafiludis, Stephanos
A1 - Džunda, Róbert
A1 - Tampubolon, Imelda Octa
A1 - Satybaldiyev, Bagdat
A1 - Emmerling, Franziska
A1 - Baláž, Matej
T1 - Calcite–aragonite transformation in an eggshell: a crucial role of organics and assessment of the impact of milling conditions on its extent using Taguchi design
N2 - The occurrence of calcite–aragonite phase transformation when a mechanically activated eggshell is triggered by the presence of the organic material (eggshell membrane).
KW - Mechanochemistry
KW - Polymorphism
PY - 2024
DO - https://doi.org/10.1039/D4CP02354D
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Parthasarathy, Thiyagaraj
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Ghosh, Soumyajit
T1 - Design of mechanically flexible photoresponsive cyanostilbene molecular crystals
N2 - Photoresponsive molecular crystals have sparked interest owing to their potential application prospects. In this study, we achieved dual mechanical responses of a cyanostilbene-based crystal BN. The crystal exhibited both stress-induced mechanical flexibility and light-induced photomechanical bending. Two distinct mechanical responses are related to different underlying phenomena and were not interlinked. While elasticity is attributed to criss-cross packing arrangement in the isotropic structure, photomechanical bending is attributed to the formation of heterogeneous phase distribution due to monomer to dimer cycloaddition product formation. The crystal did not demonstrate photoswitching activity. However, it exhibited thermal reversibility, highlighting reversible dimer to monomer conversion.
KW - Flexible
KW - Molecular crystals
PY - 2024
DO - https://doi.org/10.1039/D4CE00571F
VL - 26
SP - 4634
EP - 4642
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60888
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Mikroplastik heute: Was haben wir in den letzten Jahren erreicht?
N2 - In diesem Vortrag geht es um eine Übersicht über die Thematik der Mikroplastik, Was ist Mikroplastik, wie entsteht es und wo kommt es her. Es wird beschrieben wie eine repräsentative Probenahme erfolgen kann und wie welche Herausforderungen bei der Probenvorbereitung existieren. Die Detektion wird ausführlich beschrieben, sowohl mit Partikelanzahl als auch Masse. Im weiteren werden erste Referenzmaterialien und ihre Anwendung in internationalen Ringversuchen beschrieben. Der zweite Teil zeigt die Normungsaktivitäten im Bereich der Mikroplastik.
T2 - Mitgliederversammlung der GdCh Lackchemie
CY - Online Meeting
DA - 20.09.2024
KW - Mikroplastik
KW - TED-GC/MS
KW - Polymer 3R
KW - Reference material
KW - ILC on detection methods
PY - 2024
AN - OPUS4-61087
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miclea, Paul-Tiberiu
T1 - Membrane filter cascade for size-selective analysis of nano-and micro particles
N2 - From a metrological point of view, the analysis of micro and nanoplastics MNP requires not only representative and meaningful methods for sampling, preparation, and detection, but also defined and reproducible analytical procedures for the processes and materials used.
For such a validation of the detection procedures (including the determination of process and laboratory blank values), the filters and laboratory conditions used in interaction with the final MNP measurement play a central role for detection limits regarding MNP size, MNP content and statistical measurement control, in addition to the reference materials mentioned above. On the basis of available filtration materials (e.g. metal mesh, silicon, aluminum oxide, polycarbonate) and metrological boundary conditions, key aspects for metrologically sound method development must be defined.
Two key categories of analysis are developed for the characterization of MNP’s: analytical methods (e.g. µ-IR spectroscopy, µRaman) and mass spectrometry (eg. Py-GC/MS or TED-GC/MS). If in the first category the shape, size, number of particles and the size distribution present in the samples can be determined. In the second category the mass of the material can be measured and the volume of plastic present in the samples can be deduced from this. Both catagories are very sensitive in terms of the volume of material that can be analyzed; vibrational methods can detect single particles but mass-based method require enough particles to reach the limit of detection. That is why in this study we propose a filtration system, which in our opinion brings the two categories much closer to each other and allows true measurements of particle number and mass of the same sample. In this way it is possible not only to estimate the volume of plastic in the sample, but also to determine with much greater precision the number of particles and the type of plastic present. Furthermore, new methods for particle detection can be added and combined with existing methods. Our proposed system can be used for a single filter, but also for the use of several filters in cascade. In this way a separation of particles by size can be achieved.
T2 - 13th Annual World Congress of Nano Science & Technology 2024
CY - Osaka, Japan
DA - 22.05.2024
KW - Microplastics
KW - Si filters
KW - Filtration
KW - Polymer 3R
PY - 2024
AN - OPUS4-61097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Large-scale green synthesis of a model bsa@zif-8 biocomposite via reactive extrusion
N2 - Metal-organic framework-based biocomposites (MOF-biocomposites) hold significant promise for applications in biosensing, biocatalysis, and delivery of biopharmaceuticals. One of the most studied MOFs for bioapplications is ZIF-8 (zeolitic imidazolate framework 8) due to its high surface area, high thermal and chemical stability, and low cytotoxicity. The conventional synthesis method for ZIF-8-biocomposites, known as biomimetic mineralization, involves mixing specific biomolecules, 2-methylimidazole, and a soluble Zn2+ source in water. While this method is highly efficient, it has limitations in terms of scalability and is restricted to hydrophilic biomolecules. Aimed at developing a scalable and versatile approach, we adapted our recently reported ZIF-8 reactive extrusion for biocomposite production.
For the preparation of biocomposites, bovine serum albumin (BSA) was selected as an inexpensive model biomacromolecule. The synthesis of BSA@ZIF-8 was carried out using a twin-screw extruder at a mild temperature of 40 °C, employing a catalytic amount of EtOH following our previously explored procedure[4]. Comprehensive characterization using powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FTIR, N2 adsorption, confocal laser scanning microscopy (CLSM), and Bradford assay allowed us to optimize reaction conditions and quantify the amount of encapsulated BSA.
After thoroughly washing the extrudate with ethanol to eliminate surface-adsorbed BSA molecules, we obtained highly crystalline and pure BSA@ZIF-8 with varying BSA loadings. Notably, achieving a maximum BSA encapsulation of 26wt% was possible with 40wt% BSA in the reagent mixture. With 5wt% BSA, we reached a high encapsulation efficiency of 96%, a critical aspect for the cost-effective production of biocomposites involving expensive biomolecules. A continuous extruder operation under optimized conditions demonstrated consistent product quality, enabling the production of biocomposites on a 1.2 kd d-1 scale with a space-time yield of approximately 30000 kg m−3 d−1. These findings offer valuable insights into the cost-effective and large-scale production of ZIF-8-based biocomposites. Moreover, due to its solid-state nature, this reaction is independent of the hydrophilic or hydrophobic properties of biomolecules, providing flexibility and advantages over solvent-based processes.
T2 - International Conference on Resource Chemistry 2024
CY - Alzenau, Germany
DA - 12.03.2024
KW - Reactive Extrusion
KW - Mechanochemistry
PY - 2024
AN - OPUS4-61399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Drago, Claudia
T1 - Rapid sample preparation to detect microplastics in baby milk powder
N2 - Microplastics, ubiquitous as it is, could be released into food during production chain, through packaging and by consumer´s use. To determinate human exposure to microplastics is crucial to monitor microplastics in food matrices. The current absence of standard sample preparation procedures to identify and quantify different microplastics according to number and mass have generate time-consuming protocols and lack of comparability among different analytical methods, laboratories and time scales.
Monitoring microplastics in complex matrices as food, and in particular in baby milk powder, requires an accurate approach that need to be validate, to ensure the comparability of results. Bottled drinking water or surface waters, for example, can be measured with mass-based methods (TED-GC/MS or Py-GC/MS) directly after filtration. Baby milk powder, instead is more challenging, due to the proteins and fatty acid that clog the filters and contaminate the measuring devices with heavy carry over.
In this study, we characterize the baby milk powder by thermogravimetric analysis (TGA) and we tested different treatments for matrix reduction: water, H2O2, citric acids. In particular, the use of citric acid was tested for protein reduction before filtration. Our hypothesis was that citric acid will induce the precipitation of proteins and amino acids, leading to a strong matrix reduction. In fact, this sample pre treatment, allowed us to use a higher intake, necessary for representative quantification. Finally, the milk powder was spiked with reference material tablets containing polyethylene terephthalate (PET). The PET was not degraded by the citric acid and high recovery rate was achieved by TED-GC/MS and Py-GC/MS methods.
Considering the simplicity and accessibility of this sample preparation and its robust results, this procedure could be easily proposed as a simple sample preparation approach to monitor microplastics by mass-based methods.
T2 - MICRO 2024
CY - Arrecife, Spain
DA - 23.09.2024
KW - Microplastics
KW - Milk
KW - Polymer 3R
KW - TED-GC/MS
PY - 2024
AN - OPUS4-61273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Mechanochemistry: the Art of Upscaling
N2 - "Mechanochemistry: The Art of Upscaling" talk explores the transition from small-scale ball milling reactions to large-scale production using reactive extrusion. This talk focuses on the challenges and strategies involved in scaling up mechanochemical processes, emphasizing the critical role of in situ monitoring techniques such as Raman spectroscopy and energy-dispersive X-ray diffraction (EDXRD). These methods provide real-time insights into reaction dynamics and phase changes, enabling the optimization of process parameters for efficient and controlled upscaling. The discussion highlights key advancements in the field and their industrial applications.
T2 - SALSA Make and Measure conference
CY - Berlin, Germany
DA - 11.09.2024
KW - Mechanochemistry
KW - Reactive extrusion
PY - 2024
AN - OPUS4-61397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - DACHS/MOFs/AutoMOFs_5/Synthesis
N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters.
DACHS_MOFs is simultaneously used to test the DACHS principles.
This upload contain synthesis data from AutoMOFs_5 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample.
KW - Automation
KW - Procedure
KW - Synthesis
KW - Traceability
PY - 2024
DO - https://doi.org/10.5281/zenodo.11237987
PB - Zenodo
CY - Geneva
AN - OPUS4-61344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Moeez, A.
A1 - Hörmann, Anja
A1 - Breßler, Ingo
T1 - Example configurations and test cases for the Python HDF5Translator framework.
N2 - This is a set of use examples for the HDF5Translator framework. This framework lets you translate measurement files into a different (e.g. NeXus-compatible) structure, with some optional checks and conversions on the way. For an in-depth look at what it does, there is a blog post here.
The use examples provided herein are each accompanied by the measurement data necessary to test and replicate the conversion. The README.md files in each example show the steps necessary to do the conversion for each.
We encourage those who have used or adapted one or more of these exampes to create their own conversion, to get in touch with us so we may add your example to the set.
KW - Measurement data conversion
KW - Data conversion
KW - HDF5
KW - NeXus
KW - NXsas
KW - Framework
KW - Python
PY - 2024
DO - https://doi.org/10.5281/zenodo.10925971
PB - Zenodo
CY - Geneva
AN - OPUS4-59796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
T1 - The SPONGE
N2 - This software tool is intended to calculate X-ray scattering patterns from 3D objects described by an STL file. The fundamentals and use example(s) are shown.
T2 - Better with Scattering workshop 2020
CY - BAM, Berlin, Germany
DA - 16.03.2020
KW - Small angle scattering
KW - Software
KW - Simulation
PY - 2020
AN - OPUS4-51020
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - A place for everything: traceable science using metadata from syntheses and characterisation
N2 - In our laboratory, we rely heavily on automation for synthesis and measurement. Done right, automation can deliver reliable quantities of excruciatingly detailed data, produced in a reproducible and traceable way. This data then needs sorting and organising, and a good structure of metadata is a good start to long-lasting data.
This metadata collection is an essential part of our “holistic experimentation”-approach. In this approach, we try to ensure that all aspects of the experimental chain are performed to a high standard, so that experimental integrity is maintained. In other words: as a failure in one of the components of the chain can make an entire experiment worthless, we must ensure each component is done (and documented) well.
In this talk, we show how we 1) synthesise well-documented sample series, 2) apply a complete end-to-end X-ray scattering characterisation methodology to those samples, and 3) can link the data from the synthesis to the structural details obtained from the scattering experiments in a visual dashboard. Furthermore, we will show examples on how data can be organised in hierarchical structures in HDF5-based datafiles, and how this helps move towards more trustworthy, traceable science.
About the speaker: Brian Pauw is a full-stack X-ray scattering expert with over 15 years of experience in materials science. After earning a Ph.D. in Chemical Engineering from the Technical University of Denmark in 2009, Brian advanced scattering techniques at Japan’s National Institute for Materials Science before joining BAM (Federal Institute for Materials Research and Testing) in Germany as a permanent researcher.
At BAM, Brian focuses on small-angle scattering of polymers, metals, catalysts, and more – developing precise methodologies for data collection, correction, and analysis. They also lead efforts in laboratory automation, including robotic systems for reproducible sample preparation, aiming to enhance the efficiency and reliability of experimental workflows.
T2 - Helmholtz Metadata Collaboration: FAIR Friday Lecture Series
CY - Online meeting
DA - 09.05.2025
KW - Methodology
KW - X-ray scattering
KW - Traceability
KW - Data provenance
KW - Metadata
KW - Lab automation
KW - Holistic science
PY - 2025
AN - OPUS4-63078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Glimpses of the Future : Advancing X-ray Scattering in an Automated Materials Research Laboratory
N2 - In our (dramatically understaffed) X-ray scattering laboratory, developing a systematic, holistic methodology1 let us provide scattering and diffraction information for more than 2100 samples for 200+ projects led by 120+ collaborators. Combined with automated data correction pipelines, and our analysis and simulation software, this led to more than 40 papers2 in the last 5 years with just over 2 full-time staff members.
This year, our new, modular synthesis platform has made more than 1000 additional samples for us to analyse and catalogue. By virtue of the automation, the synthesis of these samples is automatically documented in excruciating detail, preparing them for upload and exploitation in large-scale materials databases. Having developed these proof-of-concepts, we find that materials research itself is changed dramatically by automating dull tasks in a laboratory.
This talk is intended to spark ideas and invite collaborations by providing an overview of: 1) the current improvements in our wide-range X-ray scattering laboratory methodology, 2) Introduce some of our open-source analysis and simulation software, touching on scattering, diffraction and PDF, and 3) introducing our open, modular robotic platform for systematic sample preparation. Finally, the remaining bottlenecks and points of attention across all three are highlighted.
T2 - Swiss Society for Crystallography (SSCr) annual meeting
CY - Zurich, Switzerland
DA - 08.09.2023
KW - Lab automation
KW - Fourier transforms
KW - X-ray scattering
KW - Robotic synthesis
KW - Data stewardship
KW - Holistic experimental procedures
KW - MOUSE
KW - Metal-organic frameworks
KW - High-throughput measurements
PY - 2023
AN - OPUS4-58237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Piotrowiak, T.
A1 - Reinholz, Uwe
A1 - Ludwig, A.
A1 - Emmerling, Franziska
A1 - Streli, C.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Exploring the Depths of Corrosion: A Novel GE-XANES Technique for Investigating Compositionally Complex Alloys
N2 - In this study, we propose the use of nondestructive, depth-resolved, element-specific characterization using grazing exit X-ray absorption near-edge structure spectroscopy (GE-XANES) to investigate the corrosion process in compositionally complex alloys (CCAs). By combining grazing exit X-ray fluorescence spectroscopy (GE-XRF) geometry and a pnCCD detector, we provide a scanning-free, nondestructive, depth-resolved analysis in a sub-micrometer depth range, which is especially relevant for layered materials, such as corroded CCAs. Our setup allows for spatial and energy-resolved measurements and directly extracts the desired fluorescence line, free from scattering events and other overlapping lines. We demonstrate the potential of our approach on a compositionally complex CrCoNi alloy and a layered reference sample with known composition and specific layer thickness. Our findings indicate that this new GE-XANES approach has exciting opportunities for studying surface catalysis and corrosion processes in real-world materials.
KW - Degradation mechanisms
KW - Grazin exit XANES
KW - Depth resolved XANES
KW - Compositional complex alloys
KW - Corrosion
PY - 2023
DO - https://doi.org/10.1021/acs.analchem.3c00404
VL - 95
SP - 4810
EP - 4818
PB - ACS Publications
AN - OPUS4-57823
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Simões, R. G.
A1 - Bernardes, C. E. S.
A1 - Ramisch, Yen
A1 - Bienert, Ralf
A1 - Röllig, Matthias
A1 - Emmerling, Franziska
A1 - Minas da Piedade, M. E.
T1 - Real-Time In situ XRD Study of Simvastatin Crystallization in Levitated Droplets
N2 - Simvastatin (SV) is an important active pharmaceutical ingredient (API) for treatment of hyperlipidemias, which is known to exist in different crystalline and amorphous phases. It is, therefore, an interesting model to investigate how the outcome of evaporative crystallization in the contactless environment of an acoustically levitated droplet may be influenced by key experimental conditions, such as temperature, solvent properties (e.g., polarity and hygroscopicity), and dynamics of the evaporation process. Here, we describe a real-time and in situ study of simvastatin evaporative crystallization from droplets of three solvents that differ in volatility, polarity, and protic character (acetone, ethanol, and ethyl acetate). The droplet monitorization relied on synchrotron X-ray diffraction (XRD), Raman spectroscopy, imaging, and thermographic analysis. A pronounced solvent-dependent behavior was observed. In ethanol, a simvastatin amorphous gel-like material was produced, which showed no tendency for crystallization over time; in ethyl acetate, a glassy material was formed, which crystallized on storage over a two-week period to yield simvastatin form I; and in acetone, form I crystallized upon solvent evaporation without any evident presence of a stable amorphous intermediate. The XRD and Raman results further suggested that the persistent amorphous phase obtained from ethanol and the amorphous precrystallization intermediate formed in ethyl acetate were similar. Thermographic analysis indicated that the evaporation process was accompanied by a considerable temperature decrease of the droplet surface, whose magnitude and rate correlated with the solvent volatility (acetone > ethyl acetate > ethanol). The combined thermographic and XRD results also suggested that, as the cooling effect increased, so did the amount of residual water (most likely captured from the atmosphere) remaining in the droplet after the organic solvent was lost. Finally, the interpretation of the water fingerprint in the XRD time profiles was aided by molecular dynamics simulations, which also provided insights into the possible role of H2O as an antisolvent that facilitates simvastatin crystallization.
KW - Simvastatin
KW - In-situ
KW - API
KW - Crystallization
PY - 2021
DO - https://doi.org/10.1021/acs.cgd.1c00509
SN - 1528-7483
VL - 21
IS - 8
SP - 4665
EP - 4673
PB - ACS Publications
AN - OPUS4-53663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative physic-chemical analysis of advanced materials and BAM’s green and zero-related advanced materials activities – Benefits and challenges by examples
N2 - Following points are presented:
- Nanomaterials BAM, as research materials & CRMs, incl pre-standardization, automated analysis & automated synthesis
- 2D-materials BAM HEurope ACCORDs approach Green Deal inspired correlative imaging based characterisation for safety profiling of 2D materials
- Sample preparation @BAM , inclusion to standards
- Thin Films @BAM as Reference Material Candidates, i) mesoporous, ii) HEA
- Substitutional,Transition Me oxides as electrocatalysts a project @BAM
- Sustainable mechanochemical reaction engineering projects @BAM.
T2 - VAMAS Workshop Advanced Materials Challenges and Standardization Needs for a Greener World
CY - Rio de Janeiro, Brazil
DA - 25.09.2024
KW - Nanomaterials
KW - Advanced materials
KW - 2D materials
KW - Sample preparation
KW - Thin films
KW - Reference materials
KW - Safety
KW - Automation
PY - 2024
AN - OPUS4-61404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Round Table for Expert Stakeholders - The Transfer of Research into Policy and Regulation
N2 - This talk gives an overwiew about the material and physico chemical characterisation of materials developed for the EU founded project PlasticsFate. Particles in 1st and 2nd sample set are presented next to their characterisatin and documentation in data sheets. Some materials are prepared for reference material and used in an interlaboratory comparison. Results are briefly discussed.
T2 - Stakeholder Workshop PlasticsFate
CY - Bühl, Germany
DA - 17.09.2024
KW - Microplastics
KW - Reference materials
KW - Polymer 3R
KW - Interlaboratory comparison
PY - 2024
AN - OPUS4-61088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - In situ investigations of mechanochemical processes
N2 - Overview of the present BAM activities in the field of in situ analytics of mechanochemical processes. Recent results for the synthesis of metal organic frameworks and cocrystals are presented.
T2 - HZB Seminar
CY - Online meeting
DA - 21.01.2022
KW - Mechanochemistry
KW - In situ real-time monitoring
PY - 2022
AN - OPUS4-54296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, G.
A1 - Heise, M.
A1 - Kemnitz, E.
A1 - Emmerling, Franziska
T1 - New 2D layered structures with direct fluorine-metal bonds: MF(CH3COO) (M: Sr, Ba, Pb)
N2 - New coordination polymers with 2D network structures with fluorine directly coordinated to the metal ion were prepared both via mechanochemical synthesis and fluorolytic sol–gel synthesis. Depending on the synthesis route, the samples show different particle sizes, according to SEM imaging. The crystal structures of barium acetate fluoride, strontium acetate fluoride, and lead acetate fluoride (BaFIJCH3COO), SrFIJCH3COO) and PbFIJCH3COO)) were solved from X-ray powder diffraction data. The structure solution is backed by the results from 19F MAS NMR, FT IR data, and thermal analysis. The calculated chemical shifts of the 19F MAS NMR spectra coincide well with the measured ones. It turns out that the grinding conditions have a remarkable influence on the mechanochemical synthesis and its products. Our systematic study also indicates a strong influence of the atomic radii of Ca, Sr, Ba, and Pb on the success of the syntheses.
KW - Mechanochemistry
KW - Coordination polymers
PY - 2020
DO - https://doi.org/10.1039/d0ce00287a
VL - 22
IS - 16
SP - 2772
EP - 2780
PB - Royal Society of Chemistry
AN - OPUS4-50789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bauer, J.
A1 - Miclea, P.-T.
A1 - Braun, U.
A1 - Altmann, Korinna
A1 - Turek, M.
A1 - Hagendorf, C.
T1 - Microplastic detection and analysis in water samples
N2 - Microplastic detection in water samples becomes important for tracing microplastic sources. Microplastic may harm desalination facilities by blocking filters and disturbing the marine food chain. Thermo analytical methods such as pyrolysis gas chromatography mass spectroscopy, and spectroscopic methods like (micro) Raman spectroscopy or (micro) Fouriertransform infrared spectroscopy in combination with appropriate filters and sample preparation are suitable for analyzing microplastics on a scale from 1 µm to 1000 µm fast and unambiguous. While the thermo analytical methods are suitable for larger sample volumes, Raman spectroscopy and Fouriertransform infrared spectroscopy are able to detect and analyze single microplastic particles for instance in bottled water. Machine learning algorithms ensure a reliable classification of different plastic materials.
T2 - International Conference on Sustainable Energy-Water-Environment Nexus in Desert Climate 2019
CY - Ar-Rayyan, Qatar
DA - 02.12.2019
KW - Microplastics
KW - Water samples
PY - 2022
SP - 111
EP - 113
PB - Springer
AN - OPUS4-56240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Axel
T1 - Representative sampling of roadside soil and determination of tire wear contents by TED-GC/MS
N2 - The presentation describes microplastic findings from tyre wear near roads. Both the sampling and the analysis are presented.
T2 - Mikroplastik Workshop der Hochschule Zittau
CY - Online meeting
DA - 25.11.2021
KW - Mikroplastik
KW - Reifenabrieb
KW - TED-GC/MS
KW - Probennahme
PY - 2021
AN - OPUS4-53831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feiler, Torvid
T1 - Optimierung der mechanischen Eigenschaften eines organischen Kristalles durch Polymorphismus für die Anwendung als flexibler Waveguide
N2 - Kristalle sind in der Regel spröde und neigen dazu, bei mechanischer Belastung zu brechen. Dieses Verhalten schränkt ihre Anwendungsmöglichkeiten stark ein. Durch die Entdeckung von mechanischer Flexibilität in Kristallen wurde dieses Problem gelöst. Je nach Art der Verformung können Kristalle in plastisch (irreversibel) oder elastisch (reversibel) biegbar unterteilt werden. Die Verbindung 4-Brom-6-[(6-chlorpyridin-2-ylimino)methyl]phenol (BCMPMP) ist ein vielversprechender Kandidat für die Anwendung als flexibler Waveguide. BCMPMP hat zwei verschiedene Polymorphe mit unterschiedlichen optischen und mechanischen Eigenschaften. Die spröden Kristalle der Form I zeigen eine sehr schwache Emission bei 605 nm (λex = 425 nm; Photolumineszenz-Quantenausbeute Φ = 0,4 %). Im Gegensatz dazu zeigt die plastische Form II eine starke Emission bei 585 nm (λex = 425 nm; Φ = 8,7 %). Aufgrund der mechanischen Flexibilität wurde die Eignung der Form II als Waveguide untersucht.
T2 - Tag der Chemie 2021
CY - Online meeting
DA - 06.07.2021
KW - Flexible crystals
KW - Polymorphism
KW - Waveguide
PY - 2021
AN - OPUS4-53908
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wiesner, Yosri
T1 - MIKROPLASTIK – von der Probenvorbereitung bis zur Analytik
N2 - Der Vortrag beschreibt die Herausforderungen bei der Analyse von Mikroplastik inklusive Probennahme, Probenvorbereitung und Detektion. Es werden Ergebnisse aus dem BMBF-Projekt RUSEKU vorgestellt.
T2 - LABO-Anwendertag
CY - Online meeting
DA - 23.11.2021
KW - Mikroplastik
KW - TED-GC/MS
KW - Mikroplastik-Analytik
PY - 2021
AN - OPUS4-53829
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Mikroplastik – Ein Problem für die Menschheit?
N2 - Mikroplastik findet sich in Ozeanen, Seen, Flüssen und Bächen. Es kann in unserem Boden, in der Luft und sogar in Organismen nachgewiesen werden. Jedes Jahr werden weltweit Millionen Tonnen freigesetzt. Doch wo und wie landet Mikroplastik in der Umwelt? Und wie können wir diese winzigen Partikel nachweisen?
T2 - Berlin Science Week
CY - Berlin, Germany
DA - 01.11.2021
KW - Mikroplastik
KW - TED-GC/MS
PY - 2021
AN - OPUS4-53734
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Mikroplastik Referenzmaterial und erste Vergleichsuntersuchungen
N2 - Hierbei geht es um die Vorstellung von ersten Möglichkeiten um Referenzmaterial für die Mikroplastik-Analytik herzustellen und die Ergebnisse erster Vergleichsversuche.
T2 - EUROLAB-D Workshop: Mikroplastik in der Praxis
CY - Online meeting
DA - 30.11.2021
KW - Mikroplastik
KW - Referenzmaterial
KW - Vergleichsversuche
PY - 2021
AN - OPUS4-53880
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Microplastics at BAM: TED-GC/MS and reference materials
N2 - Thsi talk aims to present the activities of microplastic analysis at BAM according to TED-GC/MS and reference materials developement.
T2 - Webinar BAM / University of Birmingham
CY - Online meeting
DA - 15.06.2021
KW - Microplastic
KW - TED-GC/MS
KW - Reference materials
PY - 2021
AN - OPUS4-53738
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Linberg, Kevin
T1 - Taking Fluorine Interaction to the Extremes using XRD and DFT Simulations
N2 - This work aims to investigate the role of F-F and F-π interactions in dictating structural and mechanical properties, through a combination of X-ray powder diffraction and dispersion-corrected density functional. As no benchmarking data exist for F-dominating organic system, we first assess how different functionals affect the mechanical properties of the material.
T2 - CRC 1349 Fluorine-Specific Interactions Symposium
CY - Online meeting
DA - 27.09.2021
KW - High Pressure
KW - Fluorine Interaction
KW - Hexafluorobenzen
KW - Density Functional Theory
PY - 2021
AN - OPUS4-53654
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feiler, Torvid
T1 - Tuning the mechanical flexibility of organic molecular crystal by polymorphism for flexible optical waveguide
N2 - Crystalline molecular materials are usually brittle and are prone to break into pieces upon external mechanical force. This fragility poses challenges for their application in next-generation technologies, including sensors, synthetic tissues, and advanced opto-electronics. The recent discovery of mechanical flexibility in single crystals of molecular materials has solved this issue and enable the design of smart flexible device technologies. Plastic crystals can be deformed permanently. This behavior is based on anisotropic molecular arrangements and the existence of facile slip planes which allow a permanent motion within the lattice. In contrast, elastic crystals can be deformed, but regain the original structure when the force is removed. This phenomenon is related to energetically isotropic molecular packing. Here we report 4-bromo-6-[(6-chlorolpyridin-2-ylimino)methyl]phenol (BCMPMP) as a promising candidate for future waveguide technologies. It turns out that BCMPMP has two different polymorphs with distinct optical and mechanical properties. Form I crystallizes in the orthorhombic space group Pca21 and shows brittle behavior. This structure exhibit very weak emission at 605 nm (λex = 425 nm) together with a low fluorescence quantum yield (Φ = 0.4 %). On the other hand, form II (monoclinic space group P21/c) has a large plastic regime and a bright emission at 585 nm (λex = 425 nm; Φ = 8.7 %). Based on its improved mechanical and optical properties, form II was explored as a bendable optical waveguide. Light was successfully propagated through a straight-shaped and mechanically deformed BCMPMP crystal. Depending on the light source, active or passive waveguiding could be achieved. So BCMPMP can also be used as a flexible wavelength filter.
T2 - International School of Crystallography in Erice
CY - Online meeting
DA - 30.05.2021
KW - Flexible crystals
KW - Polymorphism
KW - Waveguide
PY - 2021
AN - OPUS4-53905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Scoppola, E.
A1 - Jha, D.
A1 - Morales, L. F. G.
A1 - Moya, A.
A1 - Wirth, R.
A1 - Pauw, Brian Richard
A1 - Emmerling, Franziska
A1 - Van Driessche, A. E. S.
T1 - Supplementary data set for "Seeds of imperfection rule the mesocrystalline disorder in natural anhydrite single crystals"
N2 - In recent years, we have come to appreciate the astounding intricacy of the formation process of minerals from ions in aqueous solutions. In this context, a number of studies have revealed that nucleation in the calcium sulfate system is non-classical, involving the aggregation and reorganization of nanosized prenucleation particles. In a recent work we have shown that this particle-mediated nucleation pathway is actually imprinted in the resultant single micron-sized CaSO4 crystals. This property of CaSO4 minerals provides us with an unique opportunity to search for evidence of non-classical nucleation pathways in geological environments. In particular, we focused on the quintessential single crystals of anhydrite extracted from the Naica mine in Mexico. We elucidated the growth history from this mineral sample by mapping growth defects at different length scales. Based on these data we argue that the nano-scale misalignment of the structural sub-units observed in the initial calcium sulfate crystal seed propagate through different length-scales both in morphological, as well as strictly crystallographic aspects, eventually causing the formation of large mesostructured single crystals of anhydrite. Hence, the nanoparticle mediated nucleation mechanism introduces a 'seed of imperfection', which leads to a macroscopic single crystal, in which its fragments do not fit together at different length-scales in a self-similar manner. Consequently, anisotropic voids of various sizes are formed with very well-defined walls/edges. But, at the same time the material retains its essential single crystal nature. These findings shed new light on the longstanding concept of crystal structure.
KW - Calcium sulfate
KW - Mesocrystal
KW - Anhydrite
PY - 2021
DO - https://doi.org/10.5281/zenodo.4943234
PB - Zenodo
CY - Geneva
AN - OPUS4-53765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Synthesizing a library of 1000+ reproducible MOFs
N2 - While the synthesis of Metal-Organic Framework (MOF) particles can be as easy as adding two solutions together, reproducibly obtaining the same particles, time and time again, is a lot harder. As laboratory-independent reproducibility is a cornerstone of the scientific method, we must put effort into finding and controlling all necessary parameters to achieve this.
An open-source Python/EPICS-controlled robotic platform (see picture) was adapted to systematically explore this for a 20 ml MOF synthesis of the Zeolitic Imidazole Framework-8 (ZIF-8) chemistry in methanol. Parameters that were explored included: 1) addition sequence, 2) addition speeds, 3) reaction times, 4) source chemicals, 5) stirring speeds, 6) stirring bar choice, 7) starting concentrations, and 8) workup methodologies. It was found that, by controlling these parameters, highly reproducible syntheses are obtained. Secondly, the variation of these parameters alone led to a dramatic difference in volume-weighted particle size means, which exceeds an order of magnitude as investigated by our in-house X-ray scattering instrument [1].
The syntheses are thoroughly documented in an automated fashion, and the synthesis libraries as well as analyses libraries will become available in batches soon. With this library, it will be possible to extract previously unknown correlations, and other laboratories can produce specific particles by following the exact procedures of the particles of their choice.
T2 - 787. WE-Heraeus-Seminar: Accelerated Discovery of New Materials
CY - Bad Honnef, Germany
DA - 15.05.2023
KW - Metal organic frameworks
KW - Automation
KW - Lab automation
KW - Robotic-supported synthesis
KW - Reproducibility
KW - Synthesis library
KW - X-ray scattering
KW - Particle size distribution
PY - 2023
AN - OPUS4-57596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Digital Everything: X-ray Scattering and Synthesis Laboratories
N2 - In our (dramatically understaffed) X-ray scattering laboratory, developing a systematic, holistic methodology let us provide scattering and diffraction information for more than 2100 samples for 200+ projects led by 120+ collaborators. Combined with automated data correction pipelines, and our analysis and simulation software, this led to more than 40 papers in the last 5 years with just over 2 full-time staff members.
This year, our new, modular synthesis platform has made more than 1000 additional samples for us to analyse and catalogue. By virtue of the automation, the synthesis of these samples is automatically documented in excruciating detail, preparing them for upload and exploitation in large-scale materials databases.
This talk is intended to spark ideas and invite collaborations by providing an overview of: 1) the current improvements in our wide-range X-ray scattering laboratory methodology, and 2) introducing our open, modular robotic platform for systematic sample preparation.
T2 - Seminar at KIT
CY - Karlsruhe, Germany
DA - 17.08.2023
KW - Lab automation
KW - Data stewardship
KW - Scattering
KW - X-ray scattering
KW - Automated synthesis
KW - Data pipelines
PY - 2023
AN - OPUS4-58234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brirmi, M
A1 - Chabbah, T.
A1 - Chatti, S.
A1 - Schiets, F.
A1 - Casabianca, H.
A1 - Marestin, C.
A1 - Mercier, R.
A1 - Weidner, Steffen
A1 - Errachid, A.
A1 - Jaffrezic-Renault, N.
A1 - Ben Romdhane, H.
T1 - Effect of the pendent groups on biobased polymers, obtained from click chemistry suitable, for the adsorption of organic pollutants from water
N2 - In this work, four triazole-based poly(ether-pyridine)s polymers were synthesized and used as an adsorbent for the removal of phenolic compounds from aqueous solutions. For this purpose, new fluoromonomers containing 1,2,3-triazole units were prepared by the Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction and then used for the elaboration of novel poly(ether-pyridine-triazole)s (PEPTs) by direct polyconden-sation with isosorbide and bisphenol A. Chemical structure of fluorinated pyridinicmonomers as well as resulting polymers was confirmed by 1H and 19F NMR spectroscopic methods. The thermal behavior of the obtained PEPTs was characterized using differential scanning calorimetry and thermogravimetric analysis. Results of sorption showed that polymers can be effectively used as a sorbent for the removal of polarorganic pollutants. The isosorbide-based poly(ether-pyridine-triazole) which contains hydrophilic hydroxyl groups as pendants chains (P4) exhibited the highest sorption efficiencies (78%–100% after 1 h). In order to explain the results an adsorption mech-anism mainly based on π–π interactions and hydrogen bonding with the pendent groups is proposed.
KW - Adsorption
KW - Biobased polymers
KW - Cycloaddition
KW - Pentafluoropyridine
KW - Phenolic compounds
PY - 2022
DO - https://doi.org/10.1002/pat.5809
SN - 1042-7147
SP - 1
EP - 21
PB - Wiley online library
AN - OPUS4-55389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chabbah, T.
A1 - Chatti, S.
A1 - Zouaoui, F.
A1 - Jlalia, A.
A1 - Gaiji, H.
A1 - Abderrazak, H.
A1 - Casablanca, H.
A1 - Mercier, R.
A1 - Weidner, Steffen
A1 - Errachid, A.
A1 - Marestin, C.
A1 - Jaffrezic-Renault, N.
T1 - New poly(ether-phosphoramide)s sulfides based on green resources as sensitive films for the specific impedimetric detection of nickel ions
N2 - For the development of selective and sensitive chemical sensors, we have developed a new family of poly(etherphosphoramide) polymers. These polymers were obtained with satisfactory yields by nucleophilic aromatic polycondensation using isosorbide as green resources, and bisphenol A with two novel difluoro phosphinothioic amide monomers. Unprecedented, the thiophosphorylated aminoheterocycles monomers, functionalized with two heterocyclic amine, N-methylpiperazine and morpholine were successfully obtained by nucleophilic substitution reaction of P(S)–Cl compound. The resulting polymers were characterized by different analytical techniques (NMR, MALDI–ToF MS, GPC, DSC, and ATG). The resulting partially green polymers, having tertiary phosphine sulfide with P–N side chain functionalities along the main chain of polymers are the sensitive film at the surface of a gold electrode for the impedimetric detection of Cd, Ni, Pb and Hg. The bio-based poly(etherphosphoramide) functionalized with N-methylpiperazine modified sensor showed better analytical performance
than petrochemical based polymers for the detection of Ni2+. A detection limit of 50 pM was obtained which is very low compared to the previously published electrochemical sensors for nickel detection.
KW - Poly(ether-phosphoramide)s sulfides
KW - Green chemistry
KW - Polymer film
KW - MALDI TOF MS
PY - 2022
DO - https://doi.org/10.1016/j.talanta.2022.123550
VL - 247
IS - 123550
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-54980
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chabbah, T.
A1 - Chatti, S.
A1 - Jaffrezic-Renault, N.
A1 - Weidner, Steffen
A1 - Marestin, C.
A1 - Mercier, R.
T1 - Impedimetric sensors based on diethylphosphonate-containingpoly(arylene ether nitrile)s films for the detection of lead ions
N2 - This article describes the elaboration and characterization of diethylphosphonate-containing polymers coated electrodes as sensors for the detection of heavy metalstraces, by electrochemical impedance spectroscopy. Diethylphosphonate groupswere chosen as heavy metals binding sites. Two different series of polymers bearingthese anchoring groups were synthesized. Whereas the diethylphosphonate groupsare directly incorporated in the aromatic macromolecular chain in some polymers, analiphatic spacer is removing the chelating site from the polymer backbone in others.The influence of the macromolecular structure on the sensing response was studied,especially for the detection of Pb2+,Ni2+,Cd2+and Hg2+. Polymer P6, including thehigher amount of diethylphosphonate groups removed from the polymer chain by ashort alkyl spacer gave the higher sensitivity of detection of lead ions, with a detec-tion limit of 50 pM
KW - Heavy metals
KW - Phosphonate esters
KW - Lead ions
KW - MALDI TOF MS
PY - 2023
DO - https://doi.org/10.1002/pat.6065
SN - 1042-7147
SP - 1
EP - 11
PB - John Wiley & Sons, Ltd
AN - OPUS4-57356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weidner, Steffen
T1 - MALDI-ToF mass spectrometry for the characterization of biobased polymers suitable for depollution
N2 - In this work, bio-based polymers were synthesized and designed as polymers phases for adsorption of a variety of pollutants from aqueous solutions. The obtained adsorption results showed that the integration of bio-sourced synthons generate attractive hydrophilicity, and wettability of the resulting adsorbent phase. Such polymers phases enable stronger interactions with the organic and inorganic pollutants in water.
A wide variety of different bio-based polymers structures (e. g. poly(ethersulfones, poly(etherphosphines or poly(etherpyridines) with different functional groups were successfully designed in order to adapt chemical structure to different pollutants type and matrice nature.
In order to characterize and to determine the correlation between polymer structures and nature of interaction with pollutants, different analytical technics (NMR, GPC, ATG, DSC, Mass spectrometry) were successfully used. Amongst them, MALDI TOF mass spectrometry plays a superior role since this technique enables the simultaneous determination of the polymer structure, polymer end groups and molecular weight.
This work focusses on the characterization of synthesized polymers. The chemical structure of the repeating unit, the nature of the end groups, as well as the molecular weight, which are all important for the specific interactions of the polymer with the pollutants were clearly determined and suggestions to improve these interactions by changing the synthetic pathway could be given.
T2 - 12. Journees maghreb-europe. Matériaux et Applications aux Dispositifs et Capteurs
CY - Monastir, Tunisia
DA - 08.11.2022
KW - MALDI TOF MS
KW - Biobased polymers
KW - Depollution
PY - 2022
AN - OPUS4-56237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bonse, Jörn
T1 - LIPSS for beginners
N2 - This overview introduces to the phenomenon of Laser-Induced Periodic Surface Structures (LIPSS). Starting from a phenomenological introduction, the most relevant physical effects and theoretical models are discussed. Applications and future directions are outlined.
T2 - Workshop “Ultrafast Structural Transformations in Condensed Matter – Bridging Theory and Experiment”
CY - Wroclaw, Poland
DA - 09.02.2026
KW - Laser-induced periodic surface structures (LIPSS)
KW - Coherent optical scattering
KW - Nanostructures
KW - Matter reorganization
PY - 2026
AN - OPUS4-65672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Corrao, Elena
A1 - Pellegrino, Francesco
A1 - Alonso, Beatriz
A1 - Zurutuza, Amaia
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Standardized Elemental Composition Analysis of Graphene‐Related 2D Materials (GR2M) With SEM/EDS and XPS Works Reliably
N2 - Reliable quantification of the chemical composition of graphene‐related 2D materials (GR2M) as powders and liquid suspensions is a challenging task. Analytical methods such as X‐ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP‐MS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) are recommended by standardization bodies. The specific parameters to be measured are also defined, e.g., the oxygen‐to‐carbon (O/C) atomic ratio, the trace metal impurities, or the functional groups. In this contribution, for the first time, results of a systematic study on the capability of energy‐dispersive X‐ray spectroscopy (EDS) at a scanning electron microscope (SEM) to reliably quantify the O/C ratio and impurities remained from the synthesis of selected GR2M are reported. The robustness of SEM/EDS analysis is verified for various measurement conditions (different excitations and EDS detectors) and the validity of the results is tested by comparison to the established XPS analysis. Moreover, an ionic liquid is used as a reference material for the quantification of the light elements such as C, N, O and F. The study clearly demonstrates the reliability of the fast and widely available SEM/EDS as a standard method for the quantification of the elemental composition of GR2M and generally of light materials.
KW - Graphene oxide flakes
KW - Impurities
KW - O/C ratio
KW - SEM/EDS
KW - Standard
KW - XPS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656748
DO - https://doi.org/10.1002/smll.202511283
SN - 1613-6810
SP - 1
EP - 10
PB - Wiley-VHC GmbH
AN - OPUS4-65674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aliyah, K.
A1 - Berger, A.
A1 - Lazaridis, T.
A1 - Appel, C.
A1 - Prehal, C.
A1 - Menzel, A.
A1 - Guizar-Sicairos, M.
A1 - Smales, Glen J.
A1 - Pauw, Brian Richard
A1 - Gasteiger, H. A.
A1 - Gubler, L.
A1 - Büchi, F. N.
A1 - Eller, J.
T1 - Impact of Microporous Layer Composition on the Water Content in the Membrane Electrode Assembly of Polymer Electrolyte Fuel Cells
N2 - Polymer electrolyte fuel cells are paramount for future emission-free mobility. One of the vital challenges for prospering commercialization of PEFCs is water management in the cells. A microporous layer (MPL) is typically positioned between the gas Diffusion layer (GDL) and the catalyst layer (CL) to boost the cell performance and facilitate water management. In this study, three different MPLs were investigated, namely, carbon black-based MPLs with different PTFE binder contents (20 wt % PTFE as a base case and 40 wt % PTFE), as well as perforated MPLs with micron-sized pores coated on the same GDL- Substrate (Freudenberg H14). The water content in the membrane, catalyst layers (CL), and MPLs was explored using operando scanning small- and wide-angle X-ray scattering (S/WAXS). At Tcell = 80 °C, relative humidity = 100%, pabs = 3 bar, the MPL with larger pores exhibits slightly higher performance than the base case, while a considerably lower cathode CL and MPL saturation levels were observed for the MPL. In contrast, the MPL with higher amounts of PTFE binder shows lower performance than the base case, with considerably higher cathode CL and MPL saturation levels. 3D representations of how the pores could be filled in the cathode CLs were obtained from operando SAXS profiles using representative structure modeling for the different materials and operating conditions.
KW - Polymer electrolyte fuel cell
KW - Catalyst layer saturation
KW - Microporous layer saturation
KW - Membrane hydration
KW - Small and wide-angle scattering
KW - MOUSE
KW - SAXS
KW - X-ray scattering
KW - Energy storage materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656691
DO - https://doi.org/10.1021/acsami.5c22540
SN - 1944-8244
SP - 1
EP - 17
PB - American Chemical Society (ACS)
AN - OPUS4-65669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charlesworth, M.
A1 - Lampronti, G.
A1 - Belenguer, Ana M.
A1 - Day, S.
A1 - Saunders, L.
A1 - Connolly, E.
A1 - Midgley, P.
A1 - Michalchuk, Adam A. L.
T1 - Influence of Liquid on Crystallite Size Evolution During Ball Milling
N2 - Liquid assisted grinding (LAG) is a commonly used mechanochemical procedure, especially for polymorphic conversions. However, it is not understood what effect liquid additives actually play in driving mechanochemical polymorphic conversions, precluding our ability to control solid form transformations under mechanochemical conditions. We here present a time-resolved in situ (TRIS) synchrotron powder Xray diffraction (PXRD) monitoring strategy that can track, with few nm resolution, the evolution of crystalline size under liquid assisted ball milling conditions. We apply this method to investigate the influence of liquid additives on the polymorphic conversion of the 1:1 co-crystal of theophylline and benzamide, with particular focus on the role that crystallite size plays in driving ball milling induced polymorphic transformations. We find that the crystallite sizes achieved by ball milling are highly sensitive to the amount of liquid added to the reaction mixture. Liquid additives generally lead to larger crystallite sizes as compared with neat grinding protocol, with our findings indicating that crystallite size reduction is not the main factor that causes polymorph conversion under liquid assisted grinding conditions. The data presented clearly indicates the presence of an induction period before phase transformation begins with a minimum value in the crystallite size of the starting polymorph indicating the end of that induction period.
KW - Ball milling
KW - In situ diffraction
KW - Phase transformation
KW - Liquid assisted grinding
KW - Crystallite size
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656783
DO - https://doi.org/10.1021/acs.cgd.5c01662
SN - 1528-7483
SP - 1
EP - 7
PB - American Chemical Society (ACS)
AN - OPUS4-65678
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Krenzer, Julius
A1 - Petrov, Eugene P.
A1 - Biesen, Lukas
A1 - Vasylyeva, Vera
A1 - Merzenich, Sarah
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Aroyl-S,N-ketene acetal-triarylamine bichromophores – intramolecular energy transfer and dual emission upon induced aggregation and encapsulation
N2 - Aroyl-S,N-ketene acetal-based bichromophores are synthesized by a catalytic aryl amination and their photophysics are studied in the solid state, in ethanol–water mixtures inducing aggregation, and after encapsulation in polystyrene nanoparticles. The dye substitution pattern controls aggregation-induced emission and intramolecular energy transfer efficiency, resulting in single-band or dual fluorescence and a strong increase in fluorescence quantum yield upon particle encapsulation.
KW - Fluorescence
KW - Dye
KW - Aggregation
KW - Photophysics
KW - Enhancement
KW - White light emission
KW - Energy transfer
KW - Quantum yield
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656700
DO - https://doi.org/10.1039/d5ra09361a
SN - 2046-2069
VL - 16
IS - 11
SP - 10255
EP - 10260
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilberg, Alec
T1 - Untersuchung und Kompensation des Size-of-Source Effektes der Thermografie zur Prozessüberwachung in der metallischen additiven Fertigung
N2 - Der Einsatz der Thermografie zur Prozessüberwachung in der additiven Fertigung von Metallen ist aktueller Schwerpunkt diverser Forschungsprojekte. Prozessbedingt können im Bauteil Risse, innere Spannungen und sonstige interne Fehlerstellen auftreten, deren Entstehung durch wichtige thermische Größen wie Phasenumwandlungstemperaturen, Abkühlgeschwindigkeiten und thermische Gradienten beeinflusst wird. Um diese Einflüsse zu untersuchen, ist eine möglichst genaue Messung dieser Parameter notwendig.
Neben den häufig betrachteten Einflüssen des Emissionsgrades, der Umgebungstemperatur und der atmosphärischen Absorption besteht ein weiterer Einfluss, hervorgerufen durch das optische System. Der Kameraaufbau, das verwendete Objektiv und Teilchen im Strahlengang können zur Beugung, Streuung, Reflektion und Aberration der elektromagnetischen Strahlung führen, wodurch die thermografische Messung verfälscht wird. Dies ist ein in der Pyrometrie intensiv erforschter Effekt und wird, aufgrund der Abhängigkeit zur betrachteten Objektgröße, als Size-of-Source Effekt bezeichnet und in dieser Arbeit untersucht.
Im Laser-Pulver-Auftragsschweißen (LPA) wird mittels eines Lasers auf einer Substratplatte ein Schmelzbad erzeugt und durch Einblasen von Metallpulver die lagenweise Fertigung von komplexen Bauteilen ermöglicht. Dabei können, je nach geometrischer Auflösung der Kamera, Größen des Schmelzbades im Bereich weniger Prozente der gesamten Bildfläche auftreten. Aus durchgeführten Referenzmessungen an Schwarzkörperstrahlern kann in der gleichen Größenordnung eine Abweichung der Strahlungswerte im zweistelligen Prozentbereich festgestellt werden. Daher ist in diesem Anwendungsfall der dadurch verursachte Fehler nicht zu vernachlässigen, weshalb auf Basis der Referenzmessungen eine Methode entwickelt wurde, um in Abhängigkeit der Größe des Objektes einen Faktor zur Kompensation des Size-of-Source Effektes zu berechnen.
In diesem Beitrag werden erste Ergebnisse dieser im Rahmen des DFG Projektes QT-LPA (Nr. 516965606) durchgeführten Arbeiten präsentiert.
T2 - DGZfP Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - SSE
KW - Thermografie
KW - Size of source Effect
PY - 2025
AN - OPUS4-65651
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilberg, Alec
T1 - Multispektrale Thermografie zur quantitativen Temperaturbestimmung im DED-LB/M Prozess
N2 - Additive Fertigungsverfahren bieten konstruktive Freiheiten, die mit konventionellen Herstellungsverfahren nur schwer zu realisieren sind. Durch die Möglichkeit hochkomplexe Bauteile aus Metall fertigen zu können, stellt die additive Fertigung in vielen Industriezweigen eine vielversprechende Fertigungsalternative da. Allerdings treten prozessbedingt hohe Temperaturgradienten und schnelle Phasenumwandlungen auf, die maßgeblich entscheidend für die Mikrostruktur und die Bildung von internen Spannungen, Rissen und weiteren Defekten sind. Diese Effekte wirken sich direkt auf die mechanischen Eigenschaften der gefertigten Bauteile aus und verdeutlichen die Notwendigkeit einer zuverlässigen Bauteilprüfung. Dabei sind nachgelagerte Verfahren in der Regel zeit- und kostenaufwändig, weshalb die Anwendung von in-situ Verfahren zur Qualitätssicherung im Fokus diverser Forschungsprojekte steht.
Die Thermografie erlaubt die orts- und zeitaufgelöste Messung der im Prozess auftretenden Temperaturfelder. Allerdings müssen die tatsächlich gemessenen digitalen Sensorwerte mittels geeigneter radiometrischer Modelle in Temperaturen umgewandelt werden. Da diese Modelle in der Regel auf Basis von Messungen an Schwarzkörperstrahlern kalibriert werden, kann dieses Vorgehen nur zufriedenstellende Werte liefern, sofern der Emissionsgrad des zu messenden Objektes bekannt ist. Während in statischen Anwendungen häufig ein konstanter Materialreferenzwert hinreichend befriedigende Ergebnisse liefert, ist man in der additiven Fertigung mit dem Problem konfrontiert, dass der Emissionsgrad lokal in kürzester Zeit starke Änderungen durchläuft. Beeinflusst wird dieser Effekt unter anderem durch Temperatur, Phasenzustand und Oberflächenzustand.
Das hier vorgestellte Verfahren nutzt Referenzmessungen des Emissionsgrades in Abhängigkeit von Temperatur, Winkel und Phasenzustand, um in einem DED-LB/M-Prozess (auch Laser-Pulver-Auftragschweißen, LPA) sowohl den Emissionsgrad als auch die tatsächliche Temperatur orts- und zeitaufgelöst zu bestimmen. Grundlage hierfür sind multispektrale thermografische Messungen, bei denen (quasi-) synchron in acht unterschiedlichen Wellenlängenbereichen gemessen wird.
In diesem Beitrag werden Ergebnisse der im Rahmen des DFG-Projektes QT-LPA (Nr. 516965606) durchgeführten Arbeiten präsentiert.
T2 - Thermo25
CY - Garching bei München, Germany
DA - 11.11.2025
KW - Thermografie
KW - TES
KW - Multispektral
KW - DED-LB/M
KW - Laserpulverauftragschweißen
PY - 2025
AN - OPUS4-65652
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Strobach, L.
T1 - Infrarotreflektographie und Blitzthermographie zur Sichtbarmachung von historischen Farbschichten am Flugzeug Bücker Bü 181 Bestmann
N2 - Die Geschichte eines Flugzeuges ist häufig von unterschiedlichen Nutzungsphasen geprägt. Zum Beispiel ist der Wechsel des Eigentümers eines Flugzeuges häufig mit umfassenden Veränderungen der Farbgebung und Kennzeichnung verbunden. Wenn ein Flugzeug in die Sammlung eines Museums aufgenommen wird, zeigt es entweder den letzten Einsatzzustand oder andere zu späteren Zeiten durchgeführte Reparaturen auf seiner Oberfläche. Oft befinden sich unterhalb dieser letzten äußeren Schicht, ältere Spuren der Nutzung. Um diese verdeckt liegenden Lackierungen sichtbar zu machen, können die Verfahren der Infrarotreflektographie und der aktiven Thermographie eingesetzt werden. Die Infrarotreflektographie wird häufig in der Gemälderestaurierung eingesetzt, um zum Beispiel Vorzeichnungen sichtbar zu machen. Die aus der industriellen zerstörungsfreien Prüfung bekannten Verfahren der aktiven Thermographie fanden bisher überwiegend im Bereich der Bauwerksuntersuchungen Anwendung. Erste Ergebnisse zu Farbuntersuchungen an historischen Flugzeugen mit den beiden Verfahren fanden am Deutschen Museum München in Zusammenarbeit mit der TU-München statt. Ein Projekt der HTW-Berlin mit der Bundesanstalt für Materialforschung und –prüfung (BAM) und dem Militärhistorischen Museum Flugplatz Berlin-Gatow greift diese Anwendungsidee auf und vergleicht beide Verfahren. Am Beispiel des Flugzeuges Bücker Bü 181 Bestmann können die Möglichkeiten, Grenzen und Potentiale der Technologien zum gegenwärtigen Entwicklungsstand verdeutlicht werden.
T2 - Material Truth
CY - Magdeburg, Germany
DA - 04.03.2026
KW - Aktive Thermographie
KW - Flugzeuggeschichte
KW - Zerstörungsfreie Prüfung (ZfP)
KW - Infrarotreflektographie
PY - 2026
AN - OPUS4-65658
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jesus, Vinicius D.
A1 - Merizio, Leonnam G.
A1 - Galleani, Gustavo
A1 - Raffy, Guillaume
A1 - Carpentier, Mathis
A1 - Petit, Yannick
A1 - Cardinal, Thierry
A1 - de Camargo, Andrea S. S.
T1 - Energy transfer from Ag species to Nd 3+ in Ga–fluoride–phosphate glasses: near-infrared emission enhancement via controlled heat treatment and femtosecond laser inscription
N2 - Gallium fluoride–phosphate glasses are promising materials with wide optical transmission window, high volumetric density, and the ability to accommodate high concentrations of rare earth dopant ions within a tailored fluoride-rich coordination environment, resulting in high emission cross sections. In this work, the compositional system 25Ga(PO3)3–20ZnF2–30BaF2–(25–x–y)SrF2–xAgNO3–yNdF3 (x = 0–10 mol%, y = 0 or 1 mol%) was studied to understand how silver species affect the near-infrared (NIR) emission of Nd3+ ions, when the glasses are subjected to controlled heat treatment and to femtosecond direct laser writing (DLW). The glasses were obtained via the melt-quenching technique and characterized by DSC, XRD, UV-Vis-NIR absorption, and PL spectroscopy. The as-prepared glasses show broad UV-Vis excitation and emission bands arising from the coexistence of Ag+ ions and ionic Ag pairs. In samples with 10 mol% Ag+, brownish coloration and modified emission profiles indicated Ag nanoparticle formation at the surface. Heat treatment promoted the conversion of isolated Ag+ into ionic pairs, producing broadband emissions tunable by excitation wavelength and Ag+ concentration. In co-doped samples, Nd3+ introduced absorption dips in the Ag-related UV-Vis bands, consistent with energy transfer, which was further confirmed by shortened Ag excited-state lifetimes and increased Nd3+ NIR emission under UVVis excitation. In order to control the spatial distribution and size of Ag aggregates (nanoclusters, NCs) and to increase the energy transfer efficiency to Nd3+, femtosecond direct laser writing (DLW) was employed to co-doped glasses with 3 and 5 mol% Ag+. This approach enabled three-dimensional localized growth of Ag NCs with sub-micron spatial control. In the laser processed regions, the NIR emissions of Nd3+ at 900 and 1060 nm were significantly enhanced, clearly evidencing enhanced energy transfer from the localized laserinduced Ag-NCs to the Nd3+ ions. These findings suggest the possibility of tailoring high optical contrast near-IR emissions in glasses, enabling progress in advanced photonic applications.
KW - Neodymium
KW - Silver
KW - Fluoride phosphate glasses
KW - Direct laser writing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656888
DO - https://doi.org/10.1039/d5ma01430a
SN - 2633-5409
SP - 1
EP - 14
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Engelking, Lorenz
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Influence of build‑up height on residual stresses in additive repair and modification using DED‑Arc with high‑strength filler metals
N2 - Directed energy deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between additive manufactured (AM) component and semifinished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead to component failure, especially for high-strength steels. Therefore, understanding and controlling residual stresses, when combining different base and feedstock materials, is critical to improve the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and feedstock material from commercial high-strength steels. Using a robot-assisted DED-system and a controlled short arc, AM welding experiments were carried out with close to the application parameters at working temperature (200 °C) and heat input (650 kJ/m). Five hybrid AM specimens (AM wall on upright structural steel plate) were produced using a one bead per layer strategy and selected AM-wall heights between 15 and 300 mm. The influence of the AM build height on the longitudinal residual stress in the whole hybrid AM specimen (in welding direction) was analyzed and discussed. All experiments exhibit comparable stress distributions in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the building height. The height significantly influences the residual stress distribution of the deposited AM-component. Tensile residual stresses with a maximum range between 300and 400 MPa were always found in the last approx. 18 component layers (upper 40 mm). This is due to restraint of the shrinking of the top layers by the layers below. The lower layers show homogeneous residual stress distributions characterized by low compressive stresses due to the process-related tempering during the deposition of each layer on top of each other. As a result, the significant difference between the various AM build-up heights of the hybrid AM specimens is the extent (or height) of this tempered zone with low compressive stresses. These correlations contribute to the understanding of residual stress development with increasing structure height or ratio of component heights of substrate semi-finished product and AM component in hybrid additive manufacturing.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genoa, Italy
DA - 22.06.2025
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656793
DO - https://doi.org/10.1007/s40194-026-02417-y
SN - 1878-6669
SP - 1
EP - 12
PB - Spriner
AN - OPUS4-65679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oliveira Menezes, Letícia Gonçalves
A1 - Trajano Silveira, Beatriz Aiub
A1 - de Castro Raucci, Larissa Moreira Spinola
A1 - Martorano, Antônio Secco
A1 - de Oliveira, Paulo Tambasco
A1 - Arai, Marylyn Setsuko
A1 - de Camargo, Andréa Simone Stucchi
A1 - Hannig, Christian
A1 - Sterzenbach, Torsten
A1 - Brighenti, Fernanda Lourenção
A1 - de Oliveira, Analú Barros
A1 - Moraes, João Carlos Silos
A1 - Danelon, Marcelle
T1 - Functional glass ionomer cement modified with phosphate and zinc oxide nanoparticles: in vitro insights into physicomechanical behavior, cytotoxicity and antimicrobial activity
N2 - Objectives: To evaluate the effect of incorporating zinc oxide nanoparticles (ZnONPs) and sodium trimetaphosphate microparticles (TMP) into resin-modified glass ionomer cement (RMGIC) on its physicomechanical, microbiological, and cytotoxic properties.
Methods: Six groups were prepared: 1) RMGIC (Fuji II LC); 2) RMGIC-1.0 %ZnONPs; 3) RMGIC-2.0 %ZnONPs; 4) RMGIC-14.0 %TMP; 5) RMGIC-1.0 %ZnONPs-14.0 %TMP; and 6) RMGIC-2.0 %ZnONPs-14.0 %TMP. Tensile/diametral compressive strengths (TS, DCS), surface hardness (SH) and degree of monomer conversion (%DC) were evaluated in 24 h and 7 days. Fluoride (F) release was assessed over 15 days using alternating demineralizing/remineralizing solutions. Antimicrobial/antibiofilm activity against S. mutans (UA159) was assessed through adhesion, biofilm growth measurements, and XTT assays. Cytotoxicity was tested on MDPC23 odontoblasts using the resazurin assay.
Results: The DCS for the RMGIC-2.0 %ZnONPs group was 22.5 % higher when compared to RMGIC after 24 h (p <0.05); after 7 days, RMGIC-2.0 %ZnONPS-14.0 %TMP group was 23.4 % higher than RMGIC (p < 0.05). For TS after 7 days, the RMGIC-2.0 %ZnONPs-14.0 % TMP group showed the highest values (37 % and 55.4 %) than RMGIC and RMGIC-14.0 % TMP, respectively (p < 0.05). At 24 h, the RMGIC-2.0 %ZnONPs-14.0 %TMP Group showed the highest SH among all groups (p < 0.05). The greatest effect on reducing bacterial viability was observed for the RMGIC-2.0 %ZnONPs-14.0 %TMP group (p < 0.05). For cytotoxicity analysis, at 24 h, the RMGIC-1.0 %ZnONPs-14.0 %TMP group showed the highest cytocompatibility (p < 0.05). At 48 and 72 h, RMGIC-1.0 %ZnONPs, RMGIC-2.0 %ZnONPs, RMGIC-1.0 %ZnONPs-14.0 %TMP and RMGIC-2.0 %ZnONPs-14.0 %TMP groups showed the lowest cytotoxicity (p < 0.05)
KW - Phosphate and zinc oxide nanoparticles
KW - Glass ionomer
PY - 2026
DO - https://doi.org/10.1016/j.jdent.2025.106307
SN - 0300-5712
VL - 165
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-65692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghadamyari, Marzieh
A1 - Ebrahim Hosseini, Hossein
A1 - Michálková, Monika
A1 - de Camargo, Andréa Simone Stucchi
A1 - Cao, Jiangkun
A1 - Galusek, Dušan
A1 - Chukova, Oksana
A1 - Wondraczek, Lothar
A1 - Jacobsohn, Luiz Gustavo
A1 - Klement, Róbert
T1 - Broadband visible emission in undoped K2ZnGeO4 by near UV and X-ray excitation
N2 - Self-activated phosphors (SAP) have attracted significant attention for a wide range of applications, including lighting, displays, scintillators, lasers, luminescence-based sensors, bioimaging, drug delivery, and luminescent security inks. In this work, we report a new white emitting SAP, α-K2ZnGeO4, synthesized by high-temperature solid-state reaction. The phosphor crystallizes in a single-phase orthorhombic structure and consists of irregularly shaped particles. Under ultraviolet (UV) and X-ray excitation the sample exhibits broad yellowish-white emission spanning the 350–800 nm spectral range, with a long-wavelength tail extending into the near-infrared region, overlapping the biological window. Average lifetime values of 20.4 and 22.6 μs were determined from the fluorescence decay curves monitored at the centre of the band (550 nm), upon excitation at 272 and 377 nm, respectively. Additionally, the decay curve of a distinct spectral feature, peaked at 385 nm, was studied upon 272 nm excitation, yielding a lifetime of 2.3 μs. The role of structural defects (donors: VO and Zni; acceptors: VZn, VGe, and Oi) in the luminescence of α-K2ZnGeO4 was also investigated. Photoluminescence spectra recorded under 366 nm and 377 nm excitation yielded CIE 1931 chromaticity coordinates of (x, y) = (0.40213, 0.46943) and (0.39326, 0.47611), respectively. The values are almost identical and correspond to yellowish-white emission, highlighting the suitability of the material as a yellowish-white phosphor in white light-emitting diodes (wLEDs).
KW - Broadband emitter
KW - K2ZnGeO4
KW - X-ray excitation
PY - 2026
DO - https://doi.org/10.1016/j.ceramint.2026.01.063
SN - 0272-8842
VL - 52
IS - 7
SP - 8658
EP - 8669
PB - Elsevier Ltd.
AN - OPUS4-65691
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rex, Tobias
A1 - Vilela, Raquel R. C.
A1 - Bauer, Nadine
A1 - Hepp, Alexander
A1 - de Camargo, Andrea S. S.
A1 - Kiefer, Friedemann
A1 - Strassert, Cristian A.
T1 - Host–Guest Nanoparticles Incorporating a Fluorophore-Conjugated Pt(II) Complex: A Ratiometric Dual Emitter Performing as a Self-Referenced Oxygen Reporter
N2 - Ratiometric optical sensors, which provide real-time measurements by comparing the intensities of two spectrally separated emission bands, are highly effective for monitoring oxygen levels. By combining oxygen-independent and oxygensensitive emission characteristics, they offer accurate quantification, distinguishing them from other sensor types. In this work, we designed a ratiometric optical sensor concept based on a biscyclometalated platinum(II) complex coupled with an organic naphthalonitrile-based fluorophore and incorporated it into mesoporous silica nanoparticles. This encapsulation strategy significantly improved the stability and water-dispersibility of the otherwise hydrophobic coordination compound while preventing aggregation and enhancing its photophysical properties. Both the free molecule and its nanoparticle-encapsulated form were characterized, revealing high sensitivity to oxygen variations with the unique feature of self-referenced ratiometric readout. The sensor’s response was effectively measured at the single-particle level using photoluminescence microscopy, providing temporally and spatially resolved oxygen readouts. The versatility of the system was demonstrated across different experimental setups, including suspensions, solids, and agarose-embedded forms, highlighting is adaptability to a wide range of applications. This system holds significant promise for advanced oxygen monitoring, offering a reliable tool for high-resolution detection in complex environments with multiple orthogonal readouts.
KW - Oxygen sensing
KW - Ratiometric luminescence
KW - Platinum (II) complex
KW - Dual emitter probe
KW - Mesoporous silica nanoprticles
PY - 2026
DO - https://doi.org/10.1021/acsaom.5c00262
SN - 2771-9855
VL - 4
IS - 2
SP - 332
EP - 342
PB - American Chemical Society (ACS)
AN - OPUS4-65689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, Julien
A1 - Treutler, Kai
A1 - Schroepfer, Dirk
A1 - Kannengiesser, Thomas
A1 - Wesling, Volker
T1 - Influence of microstructure on the machinability and surface integrity of additively manufactured iron aluminides
N2 - The increasing global focus on energy and resource efficiency has stimulated a growing interest in additive manufacturing. AM offers economic advantages and enables an efficient use of materials. However, AM components often require subsequent mechanical post-processing, such as machining (e.g., milling), to achieve the final contours or surfaces. This is a particular challenge due to the heterogeneous and anisotropic nature of AM structures, which affect machining and the resulting component properties. High-performance materials such as iron aluminide represent a promising alternative to conventional high-temperature materials with a significant economic advantage. However, the strength and hardness properties, which are advantageous for applications in highly stressed lightweight components, pose a challenge for economical machining in addition to the AM microstructure properties. The difficult-to-cut material causes accelerated tool wear and insufficient surface quality. This study shows that crack-free additive manufacturing of the three-component system of iron-nickel-aluminum is possible, and advantages in terms of machinability compared to FeAl-AM components are achieved. The more homogeneous microstructure leads to a reduction in cutting forces, with positive effects on the machinability and optimized surface integrity. Ultrasonic assisted milling (USAM) offers great potential to address the major challenges posed by difficult-to-cut materials and additively manufactured weld structures. Therefore, this study focuses on assessing the transferability of previous positive results by USAM to the selected iron aluminide alloys. The machinability of the aluminides is analyzed by varying significant influencing variables in finish milling experiments and evaluated in terms of the loads on the tool and the resulting surface integrity.
KW - Iron aluminide
KW - Additive manufacturing
KW - Machinability
KW - Surface integrity
KW - Ultrasonic-assisted milling process
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656993
DO - https://doi.org/10.1007/s40194-026-02382-6
SN - 0043-2288
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fayis Kalady, Mohammed
A1 - Schultz, Johannes
A1 - Weinel, Kristina
A1 - Wolf, Daniel
A1 - Lubk, Axel
T1 - Geometry-dependent localization of surface plasmons on random gold nanoparticle assemblies
N2 - Assemblies of plasmonic nanoparticles (NPs) support hybridized modes of localized surface plasmons (LSPs), which delocalize in geometrically well-ordered arrangements. Here, the hybridization behavior of LSPs in geometrically completely disordered two-dimensional arrangements of Au NPs fabricated by an e-beam synthesis method is studied. Employing electron energy loss spectroscopy in a scanning transmission electron microscope and numerical simulations, the disorder-driven spatial and spectral localization of the coupled LSP modes that depends on the NP thickness is revealed. Below a NP thickness of 0.4 nm, localization increases toward higher hybridized LSP mode energies. In comparison, above 10 nm thickness, a decrease of localization toward higher mode energies is observed. In the intermediate thickness regime, a transition of the energy dependence of the localization between the two limiting cases, exhibiting a mode energy with minimal localization, is observed. It is shown that this behavior is mainly driven by the energy and thickness dependence of the polarizability of the individual NPs.
KW - Gold Nanoparticles
KW - Surface plasmons
KW - Electron enerdy loss spectroscopy (EELS)
KW - scanning transmission electron microscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647230
DO - https://doi.org/10.1103/44nk-6bp2
SN - 2643-1564
VL - 7
IS - 043053
EP - 4
PB - American Physical Society
AN - OPUS4-64723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Altmann, Korinna
A1 - Abusafia, A
A1 - Bannick, C-G
A1 - Braun, U
A1 - Crasselt, Claudia
A1 - Dittmar, S
A1 - Fuchs, M
A1 - Gehde, M
A1 - Hagendorf, C
A1 - Heller, C
A1 - Herper, D
A1 - Heymann, S
A1 - Kerndorff, A
A1 - Knefel, M
A1 - Jekel, M
A1 - Lelonek, M
A1 - Lunkenbein, T
A1 - Obermaier, N
A1 - Manhart, M
A1 - Meurer, Maren
A1 - Miclea, P-T
A1 - Paul, A
A1 - Richter, S
A1 - Ricking, M
A1 - Rohner, C
A1 - Ruhl, A
A1 - Sakai, Y
A1 - Saravia Arzabe, C
A1 - Scheid, C
A1 - Schmitt, M
A1 - Schnarr, M
A1 - Schwertfirm, F
A1 - Steinmetz, H
A1 - Wander, Lukas
A1 - Wiesner, Yosri
A1 - Zechmeister, L
T1 - RUSEKU - Repräsentative Untersuchungsstrategien für ein integratives Systemverständnis von spezifischen Einträgen von Kunststoffen in die Umwelt : Abschlussbericht
N2 - Im Verbundprojekt RUSEKU wurde die Probenahme von Wasserproben entscheidend weiterentwickelt. Wichtig ist hierbei zu gewährleisten, dass genügend Merkmalsträger in jeder Probe untersucht werden. Es muss daher eine für den Probenahmeort repräsentative Beprobung hinsichtlich des Wasservolumens in Abhängigkeit der Partikelanzahl gewährleistet sein.
Das Hauptaugenmerk lag im vorliegenden Projekt auf einer praxisnahen Beprobungsstrategie. Es wurden verschiedene Konzepte ausprobiert.
• Grundsätzlich hat sich gezeigt, dass eine Stichprobe eine Momentaufnahme des MP-Massengehaltes zeigt. Es wird eine hohe Statistik, also eine Vielzahl an Messungen am gleichen Probenahmeort, benötigt, um eine valide Aussage über den MP-Gehalt zu machen.
• Es zeigt sich, dass eine integrale Probenahme über mehrere Wochen mit dem SK routinemäßig möglich ist. Die erfassten MP-Massen sind reproduzierbar und robust.
• Die DFZ ist für Stichproben geeignet. Partikel < 50 µm werden eventuell unterschätzt
• Die fraktionierte Filtration kann für Stich- und Mischproben direkt im Feld genutzt werden. Fraktionen von 10 und 5 µm werden später im Labor Vakuum filtriert. Es erfolgt eine Fraktionierung der Probe mit Siebmaschenweiten von 1000, 500, 100, 50, 10 und 5 µm.
• Die fraktionierte Filtration kann auch anschließend an die Beprobung mit dem SK zur Anwendung kommen. Wird die mit dem SK gewonnene Wasserprobe fraktioniert filtriert, kann neben einem MP-Gesamtgehalt auch eine Einschätzung über die Partikelgrößen gewonnen werden.
• Für Wässer mit geringen Partikelzahlen wurde ein Messfiltertiegel entwickelt. Dieser hat eine Maschenweite von 6 µm. Seine Anwendung kann mögliche Verluste beim Transferieren vom Probenahmetool zum Messgefäß und mögliche Kontaminationen reduzieren.
Die Optimierung der Probenahmestrategie wurde durch Modellversuche und Simulationen unterstützt. Modellversuche zum Sinkverhalten und Simulationen von MP in realen Gewässern verdeutlichten das komplexe Verhalten der Partikel. Es konnte gezeigt werden, dass Partikel ab einer bestimmten Größe (und kleiner) bei genügend starker Turbulenz sich in der Wassersäule unabhängig von ihrer Dichte verhalten und so auch MP mit kleiner Dichte (z.B. PE) in der gesamten Wassersäule zu finden sind. Es konnte mit dem TEM die Existenz von NP gezeigt werden.
Ein wesentlicher Aspekt des RUSEKU Projektes war die Beprobung realer Kompartimente. Beprobt wurde neben Oberflächengewässern, das urbane Abwassersystem der Stadt Kaiserslautern, Waschmaschinenabwasser und Flaschenwasser.
• In Oberflächengewässern wurde hauptsächlich PE gefunden. Je nach Probe und Gewässer konnten auch PP, PS, PET, PA, SBR und Acrylate nachgewiesen werden.
• Im urbanen Abwassersystem der Stadt Kaiserslautern konnte an allen Probenahmestandorten MP nachgewiesen werden. Es wurde hauptsächlich PE, neben geringeren Mengen an PP, PS und SBR gefunden. Nach einem Regenereignis war der SBR Anteil deutlich erhöht.
• Die Beprobung eines realen Wäschepostens, bestehend aus T-Shirts und Hemden mit PA/CO oder PES/CO Mischgewebe, zeigte einen PA- und PES-Austrag im Waschwasser. Der überwiegende Teil der detektierten Fasern ist aber auf Baumwolle zurückzuführen. Reine gravimetrische Messungen zur Detektion von MP führen zu einer starken Überschätzung.
• In Flaschenwasser (PET-Flaschen) konnte MP detektiert werden. PET wurde nur im stillen Mineralwasser, nicht in Mineralwasser mit Kohlensäure gefunden werden. Teilweise wurde auch das MP-Material des Verschlusses im Wasser detektiert.
• Für Luftproben konnte ein Aufbau zur größenselektiven Beprobung getestet werden.
Neben der Probenahme hat das Projekt auch gezeigt, dass die TED-GC/MS geeignet für die MP-Detektion im Routinebetrieb ist. Die TED-GC/MS konnte weiter optimiert werden. Es wurden MP-Massen bestimmt.
Im Projekt wurden erste realitätsnahe Referenzmaterialien für die MP Detektion hergestellt. Die Herstellung von realitätsnahen Polymeren in ausreichender Homogenität und Menge hat sich als große Herausforderung herausgestellt.
KW - Mikroplastik
KW - Probennahme
KW - TED-GC/MS
KW - Fraktionierte Filtration
KW - Mikroplastikreferenzmaterial
PY - 2022
SP - 1
EP - 201
AN - OPUS4-57800
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Laboratory x-ray scattering instruments as agile test-beds towards holistic experimentation
N2 - Laboratory sources offer a unique advantage compared to synchrotron sources, largely in terms of freedom of operation. This freedom from user obligations, technology and software stacks and legacy decisions make the laboratory a very flexible place to develop and explore new ideas. The unparalleled availability furthermore allows for iterative improvement of instrumentation, sample environments and measurement methodologies to maximise the quality of the data obtained.
This talk will highlight the use of the laboratory as an agile test-bed and development space, by giving examples of some complete and incomplete investigations undertaken in our laboratory over the last years. Furthermore, it will introduce the concept of holistic experimentation, where the laboratory provides broad-ranging support for materials science investigations. This means that we assist in the experimental preparation, perform the measurements, correction and analysis, and follow-up with assistance in interpretation of our analyses in light of the results from other techniques applied to the investigation.
T2 - Invited talk at Diamond Light Source
CY - Didcot, UK
DA - 22.05.2024
KW - X-ray scattering
KW - Methodology development
KW - Laboratory management
KW - Holistic experimentation
KW - Laboratory automation
KW - Nanostructural analysis
PY - 2024
AN - OPUS4-60582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Glimpses of the Future : Oh my god it’s full of metadata!
N2 - In this talk, the importance of metadata is underscored by real-world examples.
Metadata is essential to alleviating the reproducibility crises in science. This imples that a wide range of metadata must be collected, with a heavy emphasis on the automated collection of such metadata. This must subsequently be organized in an intelligible, archival structure, when possible with units and uncertainties.
Such metadata can aid in improving the usage efficiency of instrumentation, as is demonstrated on the MOUSE instrument. This metadata can now be used to connect the various aspects of the holistic experimental procedure to gain better insights on the materials structure.
A second example shows the extraction and organization of such metadata from an automated materials development platform, collected during the synthesis of 1200 samples. These metadata from the synthesis can then be linked to the results from the analysis of these samples, to find direct correlations between the synthesis parameters and the final structure of the materials.
T2 - Helmholtz Incubator Summer Academy - Next Level Data Science
CY - Online meeting
DA - 18.09.2023
KW - Metadata
KW - Lab automation
KW - Data provenance
KW - High-throughput
KW - Correlative analysis
KW - MOUSE
KW - X-ray scattering
KW - Robotics
PY - 2023
AN - OPUS4-58463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - DACHS/MOFs/AutoMOFs_4/Synthesis
N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters.
DACHS_MOFs is simultaneously used to test the DACHS principles.
This upload contain synthesis data from AutoMOFs_4 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample.
KW - Automation
KW - Procedure
KW - Synthesis
KW - Traceability
PY - 2024
DO - https://doi.org/10.5281/zenodo.11237899
PB - Zenodo
CY - Geneva
AN - OPUS4-61343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - DACHS/MOFs/AutoMOFs_1/Synthesis
N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters.
DACHS_MOFs is simultaneously used to test the DACHS principles.
This upload contain synthesis data from AutoMOFs_1 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample.
KW - Synthesis
KW - Automation
KW - Traceability
KW - Procedure
PY - 2024
DO - https://doi.org/10.5281/zenodo.11236031
PB - Zenodo
CY - Geneva
AN - OPUS4-60243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Hörmann, Anja
A1 - Moeez, Abdul
A1 - Breßler, Ingo
T1 - BAMresearch/HDF5Translator: A Framework for translating and transforming data between HDF5 files
N2 - HDF5Translator is a Python framework for translating and transforming data between HDF5 files. It supports operations like unit conversion, dimensionality adjustments, and subtree copying, making it suitable for managing and manipulating a wide range of scientific datasets.
KW - Measurement data conversion
KW - Data conversion
KW - HDF5
KW - NeXus
KW - NXsas
KW - Framework
KW - Python
KW - Methodology
PY - 2024
DO - https://doi.org/10.5281/zenodo.10927639
PB - Zenodo
CY - Geneva
AN - OPUS4-59797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mehri Sofiani, F.
A1 - Chaudhuri, Somsubhro
A1 - Elahi, S. A.
A1 - Wallaert, E.
A1 - Depover, T.
A1 - De Waele, W.
T1 - Accelerated laboratory simulation of corrosion pit evolution in low-carbon steel using phase-field guided overpotential application
N2 - This study is performed to replicate field data of pit geometry evolution in the laboratory by accelerating pit evolution through the application of relatively high overpotential on low-carbon steel. A phase-field model is used to reduce the number of trials and errors in the laboratory. The effect of overpotential on pitting corrosion is studied in low-carbon steel in the electrolyte representative of the North Sea. Based on the results obtained through the numerical model, potentiostatic polarisation tests are performed, and a comparison is made between such accelerated tests and steel coupons collected from the field. The results of this comparison suggest that the pitting corrosion acceleration mechanism effectively produces surface conditions closely resembling those of naturally pitted steel. Additionally, it enables the investigation of the electrochemical characteristics of a stable pit over long-term exposure, where direct probing is challenging. This framework strives to mitigate the excessive costs of time-consuming coupon experiments by correlating accelerated pitting corrosion in short periods of time with actual pitting corrosion observed over the long term.
KW - Pitting corrosion
KW - Corrosion acceleration
KW - Potentiodynamic tests
KW - Phase-field
KW - S355
PY - 2025
DO - https://doi.org/10.1016/j.engfailanal.2025.110352
SN - 1350-6307
VL - 184
SP - 1
EP - 20
PB - Elsevier
CY - Oxford
AN - OPUS4-64805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - R&D insights into sustainable additive manufacturing for high-temperature applications (HTA)
N2 - Im Rahmen des AM Forums Berlin 2026 wird durch diesen Vortrag ein Einblick in FuE-Aktivitäten der BAM auf dem Gebiet der additiven Fertigung für Hochtemperaturanwendungen gegeben. Es werden dabei insbesondere Aspekte der nachhaltigen Verwendung von Pulverausgangswerkstoff und der Einfluss von Sauerstoff im Pulverwerkstoff auf die Degradation resultierender mechanischer Eigenschaften von Probekörpern beleuchtet. Die präsentierten Arbeiten sind im Rahmen des Pro FIT Projektes HTA2.0 entstanden.
T2 - 10. AM Forum 2026
CY - Berlin, Germany
DA - 10.03.2026
KW - Additive Manufacturing
KW - Sustainability
KW - Powder recycling
KW - Powder degradation
PY - 2026
AN - OPUS4-65725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hülagü, Deniz
A1 - Hertwig, Andreas
T1 - Correlative analysis of graphene: Advancing ellipsometry as a fast routine method
N2 - Graphene (G) and graphene oxide (GO) are key materials for various applications, yet their structural and thickness inhomogeneities calls for rapid, reliable characterization. In this work, we performed a correlative analysis, combining spectroscopic (SE) and imaging ellipsometry (IE) with complementary microscopy techniques to investigate monolayer graphene and GO flakes on SiO₂/Si substrates.
SEM, owing to its high resolution and excellent contrast, delivered a comprehensive overview of the monolayer graphene (Figure 1a) and enabled the clear identification of individual GO flakes (c). However, SEM does not provide layer-thickness information. In this case, SE served as a fast and non-destructive method capable of quantitative thickness determination through optical modeling, revealing a graphene layer thickness of 0.7 nm (b), corresponding to a monolayer. The GO flake identified by SEM was subsequently analyzed by AFM, a well-established technique providing nanoscale height profiles with high accuracy (d–f). AFM results further revealed flake thicknesses of a few monolayers. However, AFM is time-consuming, restricted to small scan areas, and does not offer a full overview of the sample. WLIM complemented these results by providing large-area imaging, enabling the visualization of multiple flakes simultaneously. Nevertheless, it is not able to quantify the exact thickness (e). In contrast, IE enabled non-destructive, substrate-independent thickness of GO flakes with single-atomic-layer precision and improved sensitivity, once the ellipsometer settings were optimized for material and thickness contrast and fixed during imaging, bridging the gap between overview imaging and quantitative nanoscale analysis (g–h).
While SE provides non-destructive, quantitative thickness information for homogeneous monolayer graphene, GO flakes require imaging-based methods. Therefore, IE represents an attractive alternative, offering large-area maps of GO flakes together with local layer-thickness information. This correlative approach establishes a foundation for standardized, large-area quality assessment of such 2D materials.
T2 - 13th Workshop on Spectroscopic Ellipsometry WSE 2026
CY - Genova, Italy
DA - 09.02.2026
KW - Monolayer graphene
KW - Graphene oxide
KW - Correlative Analysis
KW - SEM
KW - Spectroscopic ellipsometry
KW - Imaging ellipsometry
KW - AFM
PY - 2026
AN - OPUS4-65708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Determination, Assessment and Quantification of Hydrogen in Multi-pass / Multi-layer Weld Joints by Adapted ISO 3690 Samples - DEAQuade -
N2 - High-strength, low-alloy (HSLA) structural steels, such as S690 and higher grades, are used in numerous applications, enabling sustainable, lightweight structural construction. However, the welded joints of these steels can be susceptible to hydrogen-assisted cold cracking (HACC), especially in the hardened weld metal (WM) or heat-affected zone (HAZ). HACC in high-strength welds basically involves a critical combination of local, mutually dependent parameters consisting of: (1) a crack-critical microstructure; (2) sufficiently high mechanical stress; and (3) a diffusible hydrogen concentration (HD). In this context, thick-walled steel weld joints typically involve multi-layer welding with several passes. This leads to an effective, empirically known reduction in the global HD in the weld seam. This reduction is due to the repeated reheating of subsequently welded beads or layers, which reduces the local HD in the individual weld beads or layers. However, this has not yet been adequately quantified or described. Bead-on-plate tests, such as ISO 3690, cannot correctly reproduce the local HD distribution in individual welding passes (and thus, the global HD in the entire seam). Therefore, these tests lead to an extremely conservative evaluation of hydrogen ingress and the potential for "self-reduction" of HD due to increased interpass temperature during multi-layer welding, which has not yet been adequately addressed in the literature. Ideally, the local HD in each pass and the global (average) HD of the multi-layer weld would be known immediately after welding. For this reason, the study proposes an approach to address the local, track-, and layer-dependent, as well as global, hardness (HD) of multi-layer welds via a modified ISO 3690 test. To this end, representative welding parameter combinations for selected practical welding processes (e.g., SAW, GMAW, or SMAW) will be carried out as conventional bead-on-plate samples. These samples will be systematically extended by an increasing number of welding passes. Several sample series with an increasing number of beads or layers will be examined. Additionally, the initial HD is varied by methods such as targeted shielding gas variation (e.g., addition of hydrogen in GMAW) or moistened flux/coating (e.g., SAW/SMAW). Based on experimental data (temperature field measurements during welding and determination of temperature-dependent HD coefficients), a numerical hydrogen diffusion model is created. This model calculates the local HD (in the beads) and the HD across the weld cross-section. Additional variation calculations represent heat transfer conditions that were not recorded experimentally and their influence on HD distribution. Finally, we investigate the potential use of the modified ISO 3690 multi-layer geometry for application cases such as (1) predicting the effectiveness and necessity of hydrogen removal heat treatment procedures for given welding parameter sets and (2) extending the HD classification definition (e.g., allowing HD10 use for HSLA steels with RP0.2 > 690 MPa instead of HD5). Finally, an international round robin should be initiated once the concept has been successfully confirmed and verified.
T2 - IIW Intermediate Meeting, Com. II-A
CY - Bangkok, Thailand
DA - 17.03.2026
KW - Hydrogen assisted cracking
KW - Multi-pass welding
KW - Diffusion
KW - Cold cracking test
PY - 2026
AN - OPUS4-65716
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliute, Aiste
T1 - How experimental and computational methods allow us to design negative thermal expansion materials
N2 - Combined experimental and computational methods allow a comprehensive understanding, design, and tailoring of material properties. We focus on a well-known negative thermal expansion (NTE) material, zirconium vanadate (ZrV2O7), and address its synthesis, characterisation, and computational validation of results. Experimental and computational X-ray diffraction and Raman spectroscopy data highlighted differences between phase-pure and multiphase ceramics. The total-scattering method enabled us to distinguish subtle differences in the material's structure. Based on ab initio simulated phonon data, we could interpret the Raman spectra, visualise Raman-active atomic vibrations, and gain deeper insight into the local structure. Computational models provided deeper insight and enabled further experimental improvements, while high-quality experimental data validated and improved the computational simulation strategy.
T2 - CATS Special Guests III
CY - Urcuqui, Ecuador
DA - 06.03.2026
KW - NTE
KW - Ab initio
KW - PDF
KW - Raman
KW - XRD
PY - 2026
AN - OPUS4-65714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Schröder, Nina
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Hydrogen-assisted cracking in GMA welding of high-strength structural steel - A new look into this issue at narrow groove
N2 - Modern arc processes, such as the modified spray arc (Mod. SA), have been developed for gas metal arc welding of high-strength structural steels with which even narrow weld seams can be welded. High-strength joints are subjected to increasingly stringent requirements in terms of welding processing and the resulting component performance. In the present work, this challenge is to be met by clarifying the influences on hydrogen-assisted cracking (HAC) in a high-strength structural steel S960QL. Adapted samples analogous to the self-restraint TEKKEN test are used and analyzed with respect to crack formation, microstructure, diffusible hydrogen concentration and residual stresses. The variation of the seam opening angle of the test seams is between 30° and 60°. To prevent HAC, the effectiveness of a dehydrogenation heat treatment (DHT) from the welding heat is investigated.
As a result, the weld metals produced at reduced weld opening angle show slightly higher hydrogen concentrations on average. In addition, increased micro- as well as macro-crack formation can be observed on these weld metal samples. On all samples without DHT, cracks in the root notch occur due to HAC, which can be prevented by DHT immediately after welding.
KW - High-strength structural steel
KW - Gas metal arc welding
KW - Diffusible hydrogen
KW - Hydrogen-assisted cracking
KW - TEKKEN
KW - Residual stresses
KW - Weld metal cracking
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527260
DO - https://doi.org/10.3390/met11060904
VL - 11
IS - 6
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-52726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Meyer, A.
A1 - Weidner, Steffen
T1 - High Tm Poly(l-lactide)s by Means of Bismuth Catalysts?
N2 - One series of BiSub-catalyzed ring-opening polymerizations (ROPs) is per-formed at 160 °C for 3 days with addition of difunctional cocatalysts to find out, if poly(l-lactide) crystallizes directly from the reaction mixture. An analogous series is performed with monofunctional cocatalysts. High Tm crystal-lites (Tm > 190 °C) are obtained from all bifunctional cocatalysts, but not from all monofunctional ones. It is shown by means of SAXS measurements that the high Tm values are mainly a consequence of a transesterification–homogenization process across the lamellar surfaces resulting in thickness and smoothing of the surfaces. An unusual enthalpy-driven modification of the molecular weight distribution is found for samples that have crystallized during the polymerization. A third series of ROPs is performed at 170 °C for 2 h followed by annealing at 120 °C (2 h) to induce crystallization. Complete transformation of the resulting low Tm crystallites (Tm < 180 °C) into the high Tm crystallites by annealing at 170 °C for 1 d is not achieved, despite variation of the cocatalyst.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystallization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522777
DO - https://doi.org/10.1002/macp.202100019
SN - 1022-1352
VL - 222
IS - 8
SP - 19
PB - Wiley
AN - OPUS4-52277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About the Influence of (Non-)Solvents on the Ring Expansion Polymerization of l-Lactide and the Formation of Extended Ring Crystals
N2 - Ring-expansion polymerizations (REPs) catalyzed by two cyclic tin catalysts(2-stanna-1.3-dioxa-4,5,6,7-dibenzazepine [SnBiph] and
2,2-dibutyl-2-stanna-1,3-dithiolane [DSTL) are performed at 140 °C in bulk.
Small amounts (4 vol%) of chlorobenzene or other solvents are added to facilitate transesterification reactions (ring–ring equilibration) in the solid poly(l-lactide)s. In the mass range up to m/z 13 000 crystalline PLAs displaying a so-called saw-tooth pattern in the MALDI-TOF mass spectra are obtained indicating the formation of extended-ring crystals. The characteristics of extended-ring crystallites and folded-ring crystallites are discussed. Furthermore, extremely high melting temperatures (Tm’s up to 201.2 °C) and melting enthalpies (𝚫Hm’s up to 106 J g−1)) are found confirming that 𝚫Hmmax, the 𝚫Hm of a perfect crystal, is around or above 115 J g−1 in contrast to literature data.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Crystals
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565038
DO - https://doi.org/10.1002/macp.202200385
SN - 1022-1352
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-56503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Kricheldorf, H. R.
T1 - SnOct2-catalyzed ROPs of L-lactide initiated by acidic OH- compounds: Switching from ROP to polycondensation and cyclization
N2 - Ring-opening polymerizations (ROPs) of L-lactide are performed in bulk at 130°C with tin(II) 2-ethylhexanoate as catalyst and various phenols of differentacidity as initiators. Crystalline polylactides having phenyl ester end groups are isolated, which are almost free of cyclics. The dispersities and molecular weights are higher than those obtained from alcohol-initiated ROPs under identical conditions. Polymerizations at 160°C yield higher molecular weights than expected from the monomer/initiator ratio and a considerable fraction of cycles. The fraction of cycles increases with higher reactivity of the ester end group indicating that the cycles are formed by end-to-end cyclization.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polymerization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540250
DO - https://doi.org/10.1002/pol.20210823
SN - 2642-4150
VL - 60
IS - 5
SP - 785
EP - 793
PB - Wiley
AN - OPUS4-54025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - Multi-modal characterization for transformation of gypsum to anhydrite
N2 - We investigate recycling of gypsum waste materials and have developed a method to synthesize phase pure anhydrite in solution, while contaminants could easily be separated from products. In-situ XRD measurements were conducted in a dedicated automation setup at BESSY II to find exact reaction conditions and were supported by in-situ Raman spectroscopy.
T2 - Joint BAM-HZB Symposium on Multimodal Synchrotron Experiments for Next-Generation Materials Research
CY - Berlin, Germany
DA - 25.02.2026
KW - Recycling
KW - Automation
KW - Synchrotron XRD
KW - Raman spectroscopy
KW - Gypsum
PY - 2026
AN - OPUS4-65607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Musl, O.
A1 - Sulaeva, I.
A1 - Sumerskii, I.
A1 - Mahler, A.K.
A1 - Rosenau, T.
A1 - Falkenhagen, Jana
A1 - Potthast, A.
T1 - Mapping of the Hydrophobic Composition of Lignosulfonates
N2 - Lignosulfonates are industrial biorefinery products that are characterized by significant variability and heterogeneity in their structural composition. Typically, they exhibit high dispersities in molar mass (molar mass distribution-MMD) and in functionalities (functionality-type distribution - FTD), which crucially affect their material usage. In terms of FTD, state-of-the-art Lignin analytics still rely mainly on the determination of functional group contents, which are statistical averages with limited explanatory power. In contrast, our online hydrophobic interaction chromatography−size-exclusion chromatography 2D-LC approach combines the determination of both MMD and FTD in a single measurement to provide a comprehensive picture of the characteristic composition of industrial lignosulfonates information hitherto inaccessible by state-of-the-art lignin analytics. In this way, the complex inter - relationships between these two important structural parameters can be studied in an unprecedented manner. In this study, we reveal the considerable differences in terms of hydrophobic composition and its dispersity present in a range of different industrial lignosulfonates - data desperately needed in tailoring and refining of lignosulfonate composition for material usage.
KW - Lignosulfonates
KW - Amphiphilicity
KW - Hydrophobic interaction chromatography
KW - Two-dimensional chromatography (2D-LC)
KW - Charge-to-size-ratio
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538612
DO - https://doi.org/10.1021/acssuschemeng.1c06469
VL - 9
IS - 49
SP - 16786
EP - 16795
PB - ASC Publications
AN - OPUS4-53861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Falkenhagen, Jana
T1 - Reversible Polycondensations outside the Jacobson-Stockmayer Theory and a New Concept of Reversible Polycondensations
N2 - L-Lactide was polymerized with tin(II)acetate, tin(II)2-ethyl hexanoate, diphenyltin dichloride and dibutyltin bis(pentafluorophenoxide) at 130 °C in bulk. When an alcohol was added as initiator, linear chains free of cycles were formed having a degree of polymerization (DP) according to the lactide/initiator (LA/In) ratio.
Analogous polymerizations in the absence of an initiator yielded high molar mass cyclic polylactides.
Quite similar results were obtained when ε-caprolactone was polymerized with or without initiator.
Several transesterification experiments were conducted at 130 °C, either with polylactide or poly(ε-caprolactone) indicating that several transesterification mechanisms are operating under conditions that do not include formation of cycles by back-biting. Furthermore, reversible polycondensations (revPOCs) with low or moderate conversions were found that did not involve any kind of cyclization. Therefore, These results demonstrate the existence of revPOCs, which do neither obey the theory of irreversible polycondensation as defined by Flory nor the hypothesis of revPOCs as defined by Jacobson and Stockmayer. A new concept encompassing any kind of revPOCs is formulated in the form of a “polycondensation triangle”.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polycondensation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530831
DO - https://doi.org/10.1039/d1py00704a
VL - 12
IS - 35
SP - 5003
EP - 5016
PB - Royal Society for Chemistry
AN - OPUS4-53083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Poly(L-lactide): Optimization of Melting Temperature and Melting Enthalpy
N2 - Twice recrystallized L-lactide was polymerized with a dozen of different tin or bismuth catalysts in bulk at 160°C for 24 h and was annealed at 150°C afterwards. In two cases Tm values above 197.0°C were obtained. The parameters causing a scattering of the DSC data were studied and discussed. The samples prepared with SnCl2, 2,2-dibutyl-2-stanna-1,3-ditholane (DSTL) or cyclic tin(II) bisphenyldioxide (SnBiph) were subject to annealing programs with variation of time and temperatures, revealing that the Tm´s did not increase. However, an increase of Hm was achieved with maximum values in the range of 93-96 J g-1 corresponding to crystallinities off around 90%. Further studies were performed with once recrystallized L-lactide. Again, those samples directly crystallized from the polymerization process showed the highest Tm values. These data were compared with the equilibrium Tm0 and Hm0 data calculated by several research groups for perfect crystallites. A Tm0 of 213+/-2°C and a Hm0 of 106 J g-1 show the best agreement with the experimental data. The consequences of annealing for the thickness growth of crystallites are discussed on the basis of SAXS measurements. Finally, a comparison of cyclic and linear poly L-lactide)s is discussed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Transesterification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538656
DO - https://doi.org/10.1039/D1MA00957E
SP - 1
EP - 10
PB - Royal Society for Chemistry
AN - OPUS4-53865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fink, Friedrich
A1 - Emmerling, Franziska
A1 - Falkenhagen, Jana
T1 - Identification and Classification of Technical Lignins by means of Principle Component Analysis and k-Nearest Neighbor Algorithm
N2 - The characterization of technical lignins is a key step for the efficient use and processing of this material into valuable chemicals and for quality control. In this study 31 lignin samples were prepared from different biomass sources (hardwood, softwood, straw, grass) and different pulping processes (sulfite, Kraft, organosolv). Each lignin was analysed by attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. Statistical analysis of the ATR-FT-IR spectra by means of principal component analysis (PCA) showed significant differences between the lignins. Hence, the samples can be separated by PCA according to the original biomass. The differences observed in the ATR-FT-IR spectra result primarily from the relative ratios of the p-hydroxyphenyl, guaiacyl and syringyl units. Only limited influence of the pulping process is reflected by the spectral data. The spectra do not differ between samples processed by Kraft or organosolv processes. Lignosulfonates are clearly distinguishable by ATR-FT-IR from the other samples. For the classification a model was created using the k-nearest neighbor (k NN) algorithm. Different data pretreatment steps were compared for k=1…20. For validation purposes, a 5-fold cross-validation was chosen and the different quality criteria Accuracy (Acc), Error Rate (Err), Sensitivity (TPR) and specificity (TNR) were introduced. The optimized model for k=4 gives values for Acc = 98.9 %, Err = 1.1 %, TPR = 99.2 % and TNR = 99.6 %.
KW - Classification
KW - PCA
KW - K-nearest neighbor
KW - FT-IR
KW - Technical lignin
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533855
DO - https://doi.org/10.1002/cmtd.202100028
VL - 1
IS - 8
SP - 350
EP - 396
PB - Wiley-VCH GmbH
AN - OPUS4-53385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - High Tm linear poly(L-lactide)s prepared via alcohol-initiated ROPs of L-lactide
N2 - Alcohol-initiated ROPs of L-lactide were performed in bulk at 160 °C for 72 h with variation of the catalyst or with variation of the initiator (aliphatic alcohols). Spontaneous crystallization was only observed when cyclic Sn(II) compounds were used as a catalyst. Regardless of initiator, high melting crystallites with melting temperatures (Tm) of 189–193 °C were obtained in almost all experiments with Sn(II) 2,2′-dioxybiphenyl (SnBiph) as catalyst, even when the time was shortened to 24 h. These HTm poly(lactide)s represent the thermodynamically most stable form of poly(L-lactide). Regardless of the reaction conditions, such high melting crystallites were never obtained when Sn(II) 2-ethylhexanoate (SnOct2) was used as catalyst. SAXS measurements evidenced that formation of HTm poly(L-lactide) involves growth of the crystallite thickness, but chemical modification of the crystallite surface (smoothing) seems to be of greater importance. A hypothesis, why the “surface smoothing” is more effective for crystallites of linear chains than for crystallites composed of cycles is discussed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-opening polymerization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524330
DO - https://doi.org/10.1039/d1ra01990b
VL - 11
IS - 23
SP - 14093
EP - 14102
PB - Royal Society of Chemistry
AN - OPUS4-52433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - ROP of L-lactide and ε-caprolactone catalyzed by tin(ii) andtin(iv) acetates–switching from COOH terminated linear chains to cycles
N2 - The catalytic potential of tin(II)acetate, tin(IV)acetate, dibutyltin-bis-acetate and dioctyl tin-bis-acetate was compared based on polymerizations of L-lactide conducted in bulk at 160 or 130°C. With SnAc2 low-Lac/Cat ratios (15/1–50/1) were studied and linear chains having one acetate and one carboxyl end group almost free of cyclics were obtained. Higher monomer/catalyst ratios and lower temperatures favored formation of cycles that reached weight average molecular weights (Mw's) between 100,000 and 2,500,000. SnAc4 yielded mixtures of cycles and linear species under all reaction conditions. Dibutyltin- and dioctyl tin bis-acetate yielded cyclic polylactides under most reaction conditions with Mw's in the range of 20,000–80,000. Ring-opening polymerizations performed with ε-caprolactone showed similar trends, but the formation of COOH-terminated linear chains was significantly more favored compared to analogous experiments with lactide. The reactivity of the acetate catalysts decreased in the following order: SnAc2> SnAc4>Bu2SnAc2~Oct2SnAc2
KW - Polylactide
KW - MALDI-TOF MS
KW - Catalyst
KW - Ring-opening polymerization
KW - Tin acetates
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521923
DO - https://doi.org/10.1002/pol.20200866
VL - 59
IS - 5
SP - 439
EP - 450
PB - Wiley Online Library
AN - OPUS4-52192
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Scheliga, F.
A1 - Weidner, Steffen
T1 - What does conversion mean in polymer science?
N2 - The definition of the term “conversion” is discussed for a variety of polymer syntheses. It is demonstrated that in contrast to organic and inorganic chemistry several different definitions are needed in polymer science. The influence of increasing conversion on structure and topology of homo- and Copolymers is illustrated. Chain-growth polymerizations, such as radical polymerization or living anionic polymerizations of vinyl monomers, condensative chain polymerization, two and three-dimensional step-growth polymerizations, ring–ring or chain–chain equilibration and chemical modification of polymers are considered.
KW - Polymers
KW - Polymerization
KW - Conversion
KW - Polycondensation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523597
DO - https://doi.org/10.1002/macp.202100010
VL - 222
IS - 8
SP - 10
PB - Wiley VCH
AN - OPUS4-52359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Falkenhagen, Jana
T1 - The role of transesterifications in reversible polycondensations and a reinvestigation of the Jacobson-Beckmann-Stockmayer experiments
N2 - The polycondensations of adipic acid and 1,10-decanediol catalyzed by toluene sulfonic acid (TSA) were reinvestigated using MALDI TOF mass spectrometry and NMR spectroscopy. Unexpected reactions of TSA were detected along with incomplete conversion of the monomers. Furthermore, transesterification reactions of end-capped poly(1,10-decanediol adipate) and end-capped poly(ε-caprolactone) catalyzed by TSA were studied. Despite the quite different (ionic) reaction mechanisms, it was found that for polycondensations performed in bulk intermolecular transesterification is more efficient than the intramolecular “back-biting”; this scenario was not considered in the Jacobson–Stockmayer theory of reversible polycondensations.
These results also confirm that the Jacobson–Stockmayer explanation of reversible polycondensations solely on the basis of ring chain equilibration is not only devoid of any experimental evidence, but also in contradiction to the results elaborated in this work.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polycondensation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543402
DO - https://doi.org/10.1039/d1py01679b
SN - 1759-9962
SP - 1
EP - 9
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-54340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Ring-Expansion Polymerization of 𝝐-Caprolactone, Glycolide, and l-lactide with a Spirocyclic Tin(IV) Catalyst Derived from or 2,2′-Dihydroxy-1,1′-Binaphthyl – New Results and a Revision
N2 - In contrast to other cyclic tin bisphenoxides, polymerizations of glycolide and l-lactide with the spirocyclic tin(IV) bis-1,1′-bisnapthoxide yield linear chains having a 1,1′-bisnapthol end group and no cycles. In the case of l-lactide, LA/Cat ratio and temperature are varied and at 160 °C or below, all polylactides mainly consist of even-numbered chains. A total predominance of even-numbered chains is also found for homopolymerization of glycolide, or the copolymerization of glycolide and l-lactide, when conducted <120 °C.
Linear chains having a bisnaphthol end group are again the main reaction products of ring-expansion polymerizations (REP) of 𝝐-caprolactone, but above 150 °C cycles are also formed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polymerization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541931
DO - https://doi.org/10.1002/macp.202100308
VL - 222
IS - 24
SP - 1
EP - 10
PB - Wiley VCH GmbH
AN - OPUS4-54193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chandna, Sanjam
A1 - Povolotsky, Tatyana L.
A1 - Nie, Chuanxiong
A1 - Schwartz, Sophia
A1 - Wedepohl, Stefanie
A1 - Quaas, Elisa
A1 - Ludwig, Kai
A1 - Boyakova, Yulia
A1 - Bhatia, Sumati
A1 - Meyer, Klas
A1 - Falkenhagen, Jana
A1 - Haag, Rainer
A1 - Block, Stephan
T1 - Lignin-Based Mucus-Mimicking Antiviral Hydrogels with Enzyme Stability and Tunable Porosity
N2 - Mucus is a complex hydrogel that acts as a defensive and protective barrier in various parts of the human body. Therise in the level of viral infections has underscored the importance of advancing research into mucus-mimicking hydrogels for theefficient design of antiviral agents. Herein, we demonstrate the gram-scale synthesis of biocompatible, lignin-based virus-bindinginhibitors that reduce waste and ensure long-term availability. The lignin-based inhibitors are equipped with sulfate moieties, whichare known binding partners for many viruses, including SARS-CoV-2 and herpes viruses. In addition, cross-linking the synthesizedinhibitors yielded hydrogels that mimicked native mucus concerning surface functionality and rheology. The degree of sulfationexhibits a very strong impact on the mesh size distribution of the hydrogels, which provides a new means to fine-tune the steric andelectrostatic contributions of the virus−hydrogel interaction. This feature strongly impacts the sequestration capability of the lignin-based hydrogels, which is demonstrated by infection inhibition assays involving human herpes simplex virus 1, influenza A viruses,and the bacterium Escherichia coli (E. coli). These measurements showed a reduction in plaque-forming units (HSV-1) and colony-forming units (E. coli) by more than 4 orders of magnitude, indicating the potent inhibition by the lignin-based hydrogels
KW - Lignin functionalization
KW - Mucus-mimicking hydrogels
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625301
DO - https://doi.org/10.1021/acsami.4c18519
SP - 1
EP - 14
PB - American Chemical Society (ACS)
CY - USA
AN - OPUS4-62530
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falkenhagen, Jana
A1 - Dalgic, Mete-Sungur
A1 - Weidner, Steffen
T1 - Quantitative MALDI-TOF Mass Spectrometry of Star-Shaped Polylactides Based on Chromatographic Hyphenation
N2 - The end groups of three- and four-arm star-shaped polylactides (PLA) with trimethylolpropane and pentaerythritol core structures were functionalized with acetic acid. Reaction products with different degrees of functionalization were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Additional gradient elution liquid adsorption chromatography (GELAC) measurements were performed to determine the degree of functionalization. This technique enabled clear separation and sufficient quantification of the formed species. These chromatographic data could be used inversely to quantify mass spectrometric results, which are usually biased by the unknown ionization probabilities of different polymer end group structures. Our results showed that, in this particular case, the peak intensity in the MALDITOF mass spectra can be used to semiquantitatively determine the degree of functionalization in incompletely functionalized multiarm PLA.
KW - Polylactides
KW - MALDI-TOF-MS
KW - Gradient elution liquid adsorption chromatography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625292
DO - https://doi.org/10.1021/jasms.4c00491
SN - 1879-1123
SP - 1
EP - 9
PB - American Chemical Society (ACS)
AN - OPUS4-62529
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Scheliga, Felix
T1 - Polycondensation of L-lactic acid: a deeper look into solid state polycondensation
N2 - L-Lactic acid (LA) was condensed in the presence of SnCl2 or 4-toluenesulfonic acid (TSA) at 140 °C, and chain growth without cyclization was observed. In addition, poly(L-lactic acid)s (PLAs) with a degree of polymerization (DP) of 25, 50 or 100 were prepared by water-initiated ring-opening polymerization (ROP). These PLAs were annealed in the solid state at 140 °C and 160 °C in the presence of tin(II) 2-ethylhexanoate (SnOct2, SnCl2 or TSA). The changes in the molar mass distribution and in the topology were characterized by means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and size exclusion chromatography (SEC). With increasing time, fewer side reactions caused higher molar masses and increasing fractions of cyclic polylactides (cPLA) were obtained. Their “saw tooth” pattern in the MALDI-TOF mass spectra indicated the formation of extended ring crystallites in the solid state. TSA was the most active catalyst and caused fewer side reactions than SnCl2, which was the least reactive catalyst. Acetylation of the CH-OH end groups hindered polycondensation and prevented the formation of cPLAs. Reaction mechanisms will be discussed.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Polylaktide
KW - Solid state
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625271
DO - https://doi.org/10.1039/d4py01191k
SN - 1759-9962
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About alcohol-initiated polymerization of glycolide and separate crystallization of cyclic and linear polyglycolides
N2 - Alcohol-initiated polymerizations of glycolide (GL) catalyzed by tin(II) 2-ethylhexanoate (SnOct2) were carried out in bulk with variation of GA/In ratio, temperature and time. Due to a rather strong competition of cyclization polyglycolide (PGA) free of cycles were never obtained. When the cyclic catalysts 2,2-dibutal-2-stanna − 1,3-dithiolane (DSTL) or 2-stanna 1,3-dioxo-4,5,6,7 bibenzepane (SnBiph) were used in combination with 1,4-butanediol the influence of cyclization was even stronger. Furthermore, the degrees of polymerization were higher than the GA/alcohol ratio due to rapid polycondensation in the solid state. At 160 °C or below, the matrixassisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra indicated separate crystallization of low molar mass cyclic and linear PGAs from the same reaction mixture (also observed for poly(L-lactide)s).
KW - MALDI TOF MS
KW - Polyglycolide
KW - Ring opening polymerization
KW - Cyclization
KW - Crystallization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607282
DO - https://doi.org/10.1016/j.polymer.2024.127440
SN - 0032-3861
VL - 309
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-60728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Syntheses of cyclic polylactides and the problem of catenane formation
N2 - Cyclic poly(L-lactide)s (PLAs) were prepared in bulk either by ring-expansion polymerization (REP) or by ring-opening polymerization (ROP) with simultaneous polycondensation (ROPPOC). In contrast to REP the latter method involves formation of linear chains and thus, may involve formation of polydisperse catenanes that affect crystallization. The reprecipitated PLAs were annealed at 120 °C and compared with regard to melting temperature (Tm) and melting enthalpy (ΔHm). For similar molar masses the PLAs prepared by REP and ROPPOC had almost identical Tm's and crystallinities. Furthermore, the influence of REP and ROPPOC catalysts on the morphology of the virgin reaction products was compared.
KW - MALDI-TOF MS
KW - Catenane
KW - Polylactide
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625061
DO - https://doi.org/10.1039/d4ra08683j
VL - 15
IS - 5
SP - 3686
EP - 3692
PB - RSC
AN - OPUS4-62506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grabicki, N.
A1 - Nguyen, K. T. G.
A1 - Weidner, Steffen
A1 - Dumele, O.
T1 - Confined Spaces in [n]Cyclo-2,7-pyrenylenes
N2 - A set of strained aromatic macrocycles based on [n]cyclo2,7-(4,5,9,10-tetrahydro)pyrenylenes is presented with size dependent photophysical properties. The K-region of pyrene was functionalized with ethylene glycol groups to decorate the outer rim and thereby confine the space inside the macrocycle. This confined space is especially pronounced for n = 5, which leads to an internal binding of up to 8.0×104 M–1 between the ether-decorated [5]cyclo-2,7-pyrenylene and shape complementary crown ether–cation complexes.
Both, the ether-decorated [n]cyclo-pyrenylenes as well as one of their host–guest complexes have been structurally characterized by single crystal X-ray analysis. In combination with computational methods the structural and thermodynamic reasons for the exceptionally strong binding have been elucidated. The presented rim confinement strategy makes cycloparaphenylenes an attractive supramolecular host family with a favorable, size-independent read-out signature and binding capabilities extending beyond fullerene guests.
KW - Cycloparaphenylenes
KW - Host–guest systems
KW - Macrocycles
KW - Molecular recognition
KW - Supramolecular chemistry
PY - 2021
DO - https://doi.org/10.1002/anie.202102809
SN - 1433-7851
VL - 60
IS - 27
SP - 1
EP - 7
PB - Wiley VCH
AN - OPUS4-52517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Musl, O.
T1 - Mapping the Hydrophobic Composition of Lignosulfonates with 2D HIC-SEC aq. Liquid Chromatography
N2 - 2D-LC provides in-depth information on the complex composition of lignosulfonates – information hitherto inaccessible by state-of-the-art lignin analytics. Analysis of 12 industrial lignosulfonates revealed considerable differences in their composition and functional dispersity - properties that are crucial for lignosulfonate usage
T2 - Sustainable Materials Research Summit 2022, S.M.A.R.T
CY - Vancouver, Canada
DA - 07.08.2022
KW - Lignosulfonate
KW - Lignin
KW - Amphiphilicity
KW - Hydrophobic interaction
KW - Chromatography (HIC)
KW - Size-exclusion chromatography (SEC)
KW - Functionality type distribution
KW - Two-dimensional liquid chromatography (2D-LC)
KW - Molar mass distribution
PY - 2022
AN - OPUS4-55510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Falkenhagen, Jana
A1 - Kricheldorf, H. R.
T1 - SnOct2-catalyzed and alcohol-initiated ROPs of L-lactide – About the influence of initiators on chemical reactions in the melt and the solid state
N2 - SnOct2 (Sn(II) 2-ethylhexanoate) catalyzed ROPs of L-lactide were performed in bulk with eight different alcohols as initiators. The time was varied between 1 h and 24 h for all initiators. For two initiators the temperature was also lowered to 115 ◦C. Even-numbered chains were predominantly formed in all polymerizations at short times, but the rate of transesterification (e.g. even/odd equilibration) and the molecular weight distribution were found to depend significantly on the nature of the initiator. Observed transesterification reactions also continued in solid poly (L-lactide), and with the most active initiator, almost total equilibration was achieved even at 130 ◦C. This means that all chains including those of the crystallites were involved in transesterification reactions proceeding across the flat surfaces of the crystallites. The more or less equilibrated crystalline polylactides were characterized by DSC and SAXS measurements with regard to their melting temperature (Tm), crystallinity and crystal thickness.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystallization
KW - Catalysts
KW - SAXS
PY - 2021
DO - https://doi.org/10.1016/j.eurpolymj.2021.110508
VL - 153
SP - 110508
PB - Elsevier Ltd.
AN - OPUS4-52633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, A.
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - ROPs of L-lactide catalyzed by neat Tin(II)2-ethylhexanoate - Influence of the reaction conditions on Tm and ΔHm
N2 - L-Lactide was polymerized by means of neat SnOct2 with variation of LA/Cat ratio, temperature and time. The resulting cyclic polylactides crystallized spontaneously at 160 °C or below, but needed nucleation via mechanical stress at 165 or 170 °C. All the crystalline polylactides obtained directly from ROP above 120 °C had melting temperatures (Tm) above 189 °C (up to 194.5 °C). SnOct2 also enabled transformation of low Tm poly(L-lactide)s (Tm <180 °C) into the high Tm m1odification by annealing, due to the impact of transesterification reactions in the interphase between the crystallites. The influence of crystallization temperature and annealing time on the crystal thickness was studied via SAXS measurements. A comparison with the crystallization and annealing experiments reported by Pennings and coworkers and Tsuji and Ikada is discussed, and a satisfactory agreement has been found, because those authors also studied polyLA samples containing SnOct2 in its active form. It is also demonstrated in this work that the high Tm modification cannot be obtained when the catalyst is removed or poisoned as it is true for commercial polylactides.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystallization
PY - 2021
DO - https://doi.org/10.1016/j.polymer.2021.124122
SN - 0032-3861
VL - 231
SP - 1
EP - 10
PB - Elsevier
CY - Oxford
AN - OPUS4-53194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baumann, Maria
A1 - Falkenhagen, Jana
A1 - Weidner, Steffen
A1 - Wold, C.
A1 - Uliyanchenko, E.
T1 - Characterization of copolymers of polycarbonate and polydimethylsiloxane by 2D chromatographic separation, MALDI-TOF mass spectrometry, and FTIR spectroscopy
N2 - The structure and composition of polycarbonate polydimethylsiloxane copolymer (PC-co-PDMS) was investigated by applying various analytical approaches including chromatographic separation methods, spectrometric, and spectroscopic detection techniques. In particular, size exclusion chromatography (SEC) and liquid adsorption chromatography operating at different conditions (e.g. using gradient solvent systems) were used to achieve separations according to molar mass and functionality distribution. The coupling of both techniques resulted in fingerprint two-dimensional plots, which could be used to easily compare different copolymer batches. Matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) mass spectrometry was applied for structural investigations. The different ionization behavior of both comonomers, however, strongly limited the applicability of this technique. In contrast to that, Fourier-transform Infrared (FTIR) spectroscopy could be used to quantify the amount of PDMS in the copolymer at different points in the chromatogram. The resulting methodology was capable of distinguishing PC-co-PDMS copolymer from PC homopolymer chains present in the material.
KW - FTIR
KW - Liquid chromatography
KW - Mass spectrometry
KW - Gradient elution
KW - Polycarbonate-co-dimethylsiloxane copolymer
PY - 2020
DO - https://doi.org/10.1080/1023666X.2020.1820170
VL - 25
IS - 7
SP - 1
EP - 12
PB - Taylor & Francis
AN - OPUS4-51369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Geburtig, Anja
A1 - Wachtendorf, Volker
A1 - Falkenhagen, Jana
T1 - Combined impact of UV radiation and nitric acid (HNO3) on HDPE jerrycans – comparison of outdoor and lab test
N2 - A damaging action of HNO3-55% only occurs in combination with its decomposition into nitrous gases, which can be caused by UV radiation. In a laboratory test, transparent HDPE jerrycans have been exposed to both UV radiation and 55 wt-% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The respective damages are compared with FTIR spectroscopy in ATR and HT-gel permeation chromatography (GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. The gradual increase in oxidative damage shows the good reproducibility of the lab exposure. The decomposition of nitric acid into nitrous gases by UV radiation – as well as the jerrycan oxidation – is also observed at lower HNO3 concentration (28 wt- %). Similar results are obtained after outdoor tests. Again, the damage occurs only after combined exposure, in contrast to the exposures to UV only and to HNO3 only, which were conducted in parallel. Outdoor exposures are most readily accepted as they represent possible end-use conditions. However, the reproducibility of these exposures is poor due to the large temporal variations in weather. There are also several safety risks, which is why the number of replicates remains limited. Since the outdoor and lab exposure tests show the same qualitative results, it is appropriate to conduct systematic studies in the laboratory. After 6 days of lab exposure, the oxidation damage is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. It should be noted that this amount can also occur in two sunny weeks.
T2 - 24th iapri World Packaging Conference
CY - Valencia, Spain
DA - 17.06.2024
KW - Ppolyethylene
KW - UV exposure
KW - Nitric acid
KW - Oxidation
PY - 2024
VL - 2
SP - 30
EP - 37
PB - ITENE
AN - OPUS4-60414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Falkenhagen, Jana
T1 - Coupling of chromatographic and spectrometric techniques for polymer characterization
N2 - Coupling of chromatographic and spectrometric techniques for polymer characterization; focus topics: LCxMALDI-TOF-MS and UPLC x ESI-TOF-MS
T2 - 16. Tagung des Arbeitskreises Polymeranalytik
CY - Online meeting
DA - 22.03.2022
KW - Liquid chromatography
KW - Mass spectrometry
KW - Polymers
KW - Two-dimensional chromatography (2D-LC)
PY - 2022
AN - OPUS4-54567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fink, Friedrich
T1 - Mechanochemical valorisation of kraft-lignin
N2 - As one of nature's largest carbon sources with an annual production of around 20 billion tonnes, lignin is the third most abundant biopolymer on the planet. It becomes available as technical lignin, which is produced as a by-product in the pulp and paper industry and in smaller quantities in second generation biofuel refineries. Current estimates suggest that less than 10% of all technical lignin is reused. The high polydispersity, complex heterogeneous structure and uncertain reactivity are the major limiting factors for further processing. The most common applications for various technical lignins without extensive modifications are for example: Surface active substances, additives in bitumen, cement and animal feed. One way to make lignin usable is to break the structure into oligomer units and thus reduce the polydispersity and average molar mass. In addition, it is advantageous to introduce new functionalities such as hydroxyl or carbonyl groups when splitting the high-molecular-weight (HMW) fractions, or to convert existing functionalities. In this study, a mechanochemical method is presented that can degrade and modify technical kraft lignin by means of sodium percarbonate (SPC).
T2 - 10th Intern. Symp. on the Separation and Characterisation of Natural and Synthetic Macromolecules (SCM-10)
CY - Amsterdam, Netherlands
DA - 01.02.2023
KW - Technical Lignin
KW - Mechanochemical oxidation
PY - 2023
AN - OPUS4-57001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abderrazak, H.
T1 - Synthesis of new bio based adsorbent phases
N2 - Over the years, industrial and human activities and agricultural practices have caused a serious threat to human health and the environment. Indeed, it has been demonstrated that these activities are responsible for the presence of pollutants in the soil, air and water.
Water is one of the most strategic issues today, as it is associated with the living world. Therefore, water pollution is becoming a universal scourge that leads to environmental degradation, decrease of water quality and threatens public health.
Water pollution is mainly due to the discharge of certain harmful chemical compounds that are not very or not at all biodegradable (phenolic compounds, heavy metals, hydrocarbons, dyes, pesticides, etc.) by various industries: chemical, pharmaceutical, textile, food processing, etc. The impact of these industrial effluents on fauna and flora is very harmful. A sensitization of the socio-economic actors and the public, accompanied by a severe regulation in relation to the discharges, would contribute to fight against this drift, but also, by the development of effective methods allowing to remove these pollutants, not only in an analytical purpose but also of depollution.
Thus and within the framework of the preservation of an environment with regard to any anthropogenic activity, our research topic relates to the use of original biosourced polymeric phases for the extraction of the organic compounds and the heavy metals in aqueous mediums.
Therefore, we have proceeded to the synthesis and characterization of a large variety of monomers, polymers and cross-linked materials. These products, partially derived from biomass, contain various functional groups with the ability to interact with chemical components without discriminating effect.
The developed polymer phases have been successfully used for the adsorption of some organic pollutants and heavy metals in synthetic aqueous solutions.
T2 - 12. Journees maghreb-europe. Matériaux et Applications aux Dispositifs et Capteurs
CY - Monastir, Tunisia
DA - 08.11.2022
KW - Organic-inorganic adsorbents
KW - Semi-Interpenetrating Network
KW - Poly(ether-sulfone)
KW - Reversible adsorption.
PY - 2022
AN - OPUS4-56286
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weidner, Steffen
T1 - MALDI TOF MS zur Aufklärung von Kristallisationsprozessen in Polyestern
N2 - MALDI TOF Massenspektrometrie wurde verwendet, um Kristallisationsprozesse in Polyestern (Polylactide, Polyglycolide) zu untersuchen. Dabei konnte gezeigt werden, dass Zyklen und Linearen simultan, aber in unterschiedlichen Kristalliten, kristallisieren. Die dabei ablaufenden Umesterungen (Transesterifizierungen) konnten mit der MALDI TOF Massenspektrometrie nachgewiesen werden. Damit wurde ein völlig neues Anwendungsgebiet dieser MS Methode demonstriert.
T2 - 28. Kolloquium Massenspektrometrie von Polymeren
CY - Berlin, Germany
DA - 14.05.2024
KW - MALDI TOF MS
KW - Bioabbaubare Polymere
KW - Crystallinity
PY - 2024
AN - OPUS4-60029
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jlalia, I.
A1 - Chabbah, T.
A1 - Chatti, S.
A1 - Schiets, F.
A1 - Casabianca, H.
A1 - Marestin, C.
A1 - Mercier, R.
A1 - Weidner, Steffen
A1 - Kricheldorf, H. R.
A1 - Errachid, A.
A1 - Vulliet, E.
A1 - Hammani, M.
A1 - Jaffrezic-Renault, N.
T1 - Alternating bio-based pyridinic copolymers modified with hydrophilic and hydrophobic spacers as sorbents of aromatic pollutants
N2 - The main objective of this work was to design new advanced sorbent phases, alternating copolymers, derived from isosorbide and 2,6-difluorpyridine, to be used for the removal of aromatic organic pollutants present in water at low concentrations. Six different monomers, dianhydrohexitols isomers and bisphenol derivatives, weresynthesized in order to make it possible to study their hydrophilic and hydrophobiceffect on the sorption efficiency of the resulting polymeric phases. Before this study, we have confirmed the chemicals structures, molecular weights, and thermal properties of the obtained polymeric phases. Sorption results show a higher adsorption efficiency of P6 co-poly(ether-pyridine) based on bisphenol substituted with pyridineunits, for all tested pollutants, hydrophobic and hydrophilic ones, due to its less compact structure. Two aromatic organic pollutants, p-hydroxybenzoic acid and toluicacid, were selected as sorbates to study the adsorption characteristic, kinetics and isotherms of the copoly(ether pyridine) P6. Langmuir model led to a better fitting of the sorption isotherms; the sorption of toluic acid is easier than of that p-hydroxybenzoic acid. Comparing 1/n values for benzoic acid was two time lower for P6 compared to that for biochar and for crosslinked methacrylate resin, showing a higher efficiency
KW - Alternating co-poly(ether pyridine)s
KW - Aromatic organic compounds,
KW - Biosourced isosorbide
KW - Sorption isotherm
KW - Sorption mechanism
PY - 2021
DO - https://doi.org/10.1002/pat.5578
VL - 33
IS - 4
SP - 1057
EP - 1068
PB - Wiley Online Library
AN - OPUS4-54031
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fink, Friedrich
A1 - Stawski, Tomasz M.
A1 - Stockmann, Jörg Manfred
A1 - Emmerling, Franziska
A1 - Falkenhagen, Jana
T1 - Surface Modification of Kraft Lignin by Mechanochemical Processing with Sodium Percarbonate
N2 - In this article, we present a novel one-pot mechanochemical reaction for the surface activation of lignin.
The process involves environmentally friendly oxidation with hydrogen peroxide, depolymerization of fractions with high molecular mass, and introduction of new carbonyl functions into the lignin backbone. Kraft lignin was ground with sodium percarbonate and sodium hydroxide in a ball mill at different time intervals. Analyses by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), size exclusion chromatography (SEC), dynamic vapor sorption (DVS), and small-angle X-ray scattering (SAXS) showed significant improvements. After only 5 min of reaction, there was a 47% reduction in mass-average molecular weight and an increase in carboxyl functionalities.
Chemical activation resulted in an approximately 2.8-fold increase in water adsorption. Principal component analysis (PCA) provided further insight into the correlations between IR spectra and SAXS parameters
KW - Kraft Lignin
KW - Mechanochemical oxidation
KW - SEC
KW - FTIR
KW - SAXS
KW - PCA
PY - 2023
DO - https://doi.org/10.1021/acs.biomac.3c00584
SN - 1525-7797
SP - 1
EP - 11
PB - American Chemical Society
AN - OPUS4-58074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Ring-expansion polymerization (REP) of L-lactide with cyclic tin catalysts – About formation of extended ring crystals and optimization of Tm and ΔHm
N2 - L-Lactide was polymerized in bulk at 140 °C with three different cyclic tin catalysts and the time was varied from 1 d up to 14 d. The MALDI TOF spectra confirmed the formation of cyclic polylactides (PLAs) and displayed a characteristic change of peak intensity distribution with formation of a “saw tooth pattern”. This pattern confirms a previous hypothesis that cyclic PLAs tend to form crystallites with extended ring conformation and relatively smooth surface. This type of crystallites is formed under thermodynamic control by transesterification on the surface of the crystallites. In this way PLAs with extraordinarily high melting temperatures (Tm's up to 200.6 °C) and extraordinarily high melting enthalpy were obtained (ΔHm's up to 105 J g−1). These ΔHm values require a revision of the maximum ΔHm value calculated in the literature for ideal PLA crystals.
KW - Polylactide
KW - MALDI-TOF MS
KW - ring-expansion polymerization
PY - 2022
DO - https://doi.org/10.1016/j.polymer.2022.125516
SN - 0032-3861
VL - 263
SP - 125516
PB - Elsevier Ltd.
AN - OPUS4-56338
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, A.
A1 - Anis, B.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
T1 - Graphene Oxide/Polyvinyl Alcohol–Formaldehyde Composite Loaded by Pb Ions: Structure and Electrochemical Performance
N2 - An immobilization of graphene oxide (GO) into a matrix of polyvinyl formaldehyde (PVF) foam as an eco-friendly, low cost, superior, and easily recovered sorbent of Pb ions from an aqueous solution is described. The relationships between the structure and electrochemical properties of PVF/GO composite with implanted Pb ions are discussed for the first time. The number of alcohol groups decreased by 41% and 63% for PVF/GO and the PVF/GO/Pb composite, respectively, compared to pure PVF. This means that chemical bonds are formed between the Pb ions and the PVF/GO composite based on the OH groups. This bond formation causes an increase in the Tg values attributed to the formation of a strong surface complexation between adjacent layers of PVF/GO composite. The conductivity increases by about 2.8 orders of magnitude compared to the values of the PVF/GO/Pb composite compared to the PVF. This means the presence of Pb ions is the main factor for enhancing the conductivity where the conduction mechanism is changed from ionic for PVF to electronic conduction for PVF/GO and PVF/GO/Pb.
KW - Graphene oxide
KW - Polyvinyl formaldehyde
KW - Lead ions
KW - Conductivity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549588
DO - https://doi.org/10.3390/polym14112303
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-54958
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Szymoniak, Paulina
A1 - Tavasolyzadeh, Zeynab
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - Multiphoton lithography of interpenetrating polymer networks for tailored microstructure thermal and micromechanical properties
N2 - Multiphoton lithography (MPL), an emerging truly 3D microfabrication technique, exhibits substantial potential in biomedical applications, including drug delivery and tissue engineering. Fabricated micro-objects are often expected to undergo shape morphing or bending of the entire structure or its parts. Furthermore, ensuring precise property tuning is detrimental to the realization of the functionality of MPL microstructures. Herein, novel MPL materials based on interpenetrating polymer networks (IPNs) are presented that effectively combine the advantages of acrylate and epoxy systems. IPNs with varying component ratios are investigated for their microfabrication performance and structural integrity with respect to thermal and micromechanical properties. A variety of high-resolution techniques is applied to comprehensively evaluate IPN properties at the bulk, micron, and segmental levels. This study shows that the MPL laser scanning velocity and power, photoinitiator content, and multi-step exposure can be used to tune the morphology and properties of the IPN. As a result, a library of 3D MPL IPN microstructures with high 3D structural stability and tailored thermal and micromechanical properties is achieved. New IPN microstructures with Young’s moduli of 3–4 MPa demonstrate high-to-fully elastic responses to deformations, making them promising for applications in morphable microsystems, soft micro-robotics, and cell engineering.
KW - Interpenetrating polymer network
KW - Multiphoton lithography
KW - Atomic force microscopy
KW - Intermodulation AFM
KW - Fast scanning calorimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600593
DO - https://doi.org/10.1002/smll.202310580
SN - 1613-6810
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-60059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Huang, J.
A1 - Szymoniak, Paulina
A1 - Bojdys, M. J.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Structure and molecular mobility of phosphinine-based covalent organic frameworks – glass transition of amorphous COFs
N2 - Two-dimensional covalent organic frameworks (COFs) based on phosphinine and thiophene building blocks have been synthesized with two different side groups. The materials are denoted as CPSF-MeO and CPSF-EtO where CxxF correspond to the covalent framework, whereas P and S are related to heteroatoms phosphorous and sulfur. MeO and EtO indicate the substituents, i.e. methoxy and ethoxy.
Their morphologies were studied by scanning electron microcopy and X-ray scattering. The absence of crystalline reflexes in the X-ray pattern reveal that both materials are amorphous and can be considered as glasses. Furthermore, N2 adsorption measurements indicate substantial Brunauer–Emmett–Teller (BET) surface area values pointing to the formation of three-dimensional pores by stacking of the aromatic 2D layer. An analysis of the porosity of both COFs showed a mean radius of the pores to be of ca. 4 nm, consistent with their chemical structure. The COFs form nanoparticles with a radius of around 100 nm. The thermal behavior of the COFs was further investigated by fast scanning calorimetry. These investigations showed that both COFs undergo a glass transition. The glass transition temperature of CPSF-EtO is found to be ca. 100 K higher than that for CPSF-MeO. This large difference in the glass transition is discussed to be due to a change in the interaction of the COF sheets induced by the longer ethoxy group. It might be assumed that for CPSF-EtO more individual COF sheets assemble to larger stacks than for CPSF-MeO. This agrees with the much larger surface area value found for CPSF-EtO compared to CPSF-MeO. To corroborate the results obtained be fast scanning calorimetry dielectric measurements were conducted which confirm the occurrence of a dynamic glass transition. The estimated temperature dependence of the relaxation rates of the dielectric relaxation and their absolute values agrees well with the data obtained by fast scanning calorimetry. Considering the fragility approach to the glass transition, it was further found that CPSF-MeO is a fragile glass former whereas CPSF-EtO behaves as a strong glass forming material. This difference in the fragility points also to distinct differences in the interaction between the 2D COF molecules in both materials.
KW - Covalent Organic frameworks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596770
DO - https://doi.org/10.1039/d3ma01123b
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Malpass-Evans, R.
A1 - McKeown, N.
A1 - Jalarvo, N.
A1 - Tyagi, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Microscopic molecular mobility of high-performance polymers of intrinsic microporosity revealed by neutron scattering – bend fluctuations and signature of methyl group rotation
N2 - Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH3) and its demethylated counterpart PIM-EA-TB(H2), which have high Brunauer–Emmett–Teller surface area values of 1030 m2 g-1 and 836 m2 g-1, respectively. As these two polymers only differ in the presence of two methyl groups at the ethanoanthracene unit, the effect of methyl group rotation can be investigated solely. To cover a broad dynamic range, neutron time-of-flight was combined with neutron backscattering. The demethylated PIM-EA-TB(H2) exhibits a relaxation process with a weak intensity at short times. As the backbone is rigid and stiff this process was assigned to bendand-flex fluctuations. This process was also observed for the PIM-EA-TB(CH3). A further relaxation process is found for PIM-EA-TB(CH3), which is the methyl group rotation. It was analyzed by a jump-diffusion in a three-fold potential considering also the fact that only a fraction of the present hydrogens in PIM-EATB(CH3) participate in the methyl group rotation. This analysis can quantitatively describe the q dependence of the elastic incoherent structure factor. Furthermore, a relaxation time for the methyl group rotation can be extracted. A high activation energy of 35 kJ mol-1 was deduced. This high activation energy evidences a strong hindrance of the methyl group rotation in the bridged PIM-EA-TB(CH3) structure.
KW - Polymers of Intrinsic Microporosity
KW - Neutron Scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604114
DO - https://doi.org/10.1039/d4sm00520a
SP - 1
EP - 11
PB - RSC
AN - OPUS4-60411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed Aejaz
A1 - Szymoniak, Paulina
A1 - Zorn, R.
A1 - Böhning, Martin
A1 - Wolff, M.
A1 - Zamponi, M.
A1 - Schönhals, Andreas
T1 - Molecular mobility in high-performance polynorbornenes:A combined broadband dielectric, advanced calorimetry,and neutron scattering investigation
N2 - The molecular dynamics of two addition type polynorbornenes, exo-PNBSiand PTCNSi1, bearing microporosity has been investigated by broadbanddielectric spectroscopy, fast scanning calorimetry, and neutron scattering. Bothpolymers have the same side groups but different backbones. Due to theirfavorable transport properties, these polymers have potential applications inseparation membranes for gases. It is established in literature that molecularfluctuations are important for the diffusion of small molecules through poly-mers. For exo-PNBSi, two dielectric processes are observed, which are assignedto Maxwell/Wagner/Sillars (MWS) process due to blocking of charge carriersat internal voids or pore walls. For PTCNSi1, one MWS-polarization process isfound. This points to a bimodal pore-size distribution for exo-PNBSi. A glasstransition for exo-PNBSi and for PTCNSi1 could be evidenced for the first timeusing fast scanning calorimetry. For Tgand the corresponding apparent activa-tion energy, higher values were found for PTCNSi1 compared to exo-PNBSi.For both polymers, the neutron scattering data reveal one relaxation process.This process is mainly assigned to methyl group rotation probably overlayedby carbon–carbon torsional fluctuations.
KW - Advanced calorimetry
KW - Dielectric spectroscopy
KW - Neutron scattering
KW - Polynorbornenes
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547086
DO - https://doi.org/10.1002/pen.25995
SN - 0032-3888
VL - 62
IS - 7
SP - 2143
EP - 2155
PB - Wiley
AN - OPUS4-54708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Hiid, Gundula
A1 - Szymoniak, Paulina
A1 - Hertwig, Andreas
A1 - Schönhals, Andreas
T1 - Growth kinetics of the adsorbed layer of poly(bisphenol A carbonate) and its effect on the glass transition behavior in thin films
N2 - The glass transition behavior of thin films of poly(bisphenol A carbonate) (PBAC) was studied employing ellipsometry. The glass transition temperature increases with the reduction of the film thickness. This result is attributed to the formation of an adsorbed layer with a reduced mobility compared to bulk PBAC. Therefore, for the first time, the growth kinetics of the adsorbed layer of PBAC was investigated, prepared by leaching samples from a 200 nm thin film which were annealed for several times at three different temperatures. The thickness of each prepared adsorbed layer was measured by multiple scans using atomic force microscopy (AFM). Additionally, an unannealed sample was measured. Comparison of the measurements of the unannealed and the annealed samples provides proof of a pre-growth regime for all annealing temperatures which was not observed for other polymers. For the lowest annealing temperature after the pre-growth stage only a growth regime with a linear time dependence is observed. For higher annealing temperatures the growth kinetics changes from a linear to a logarithmic growth regime at a critical time. At the longest annealing times the films showed signs of dewetting where segments of the adsorbed film were removed from the substrate (dewetting by desorption). The dependence of the surface roughness of the PBAC surface on annealing time also confirmed that the films annealed at highest temperatures for the longest times desorbed from the substrate.
KW - Ultra thin polymer films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574531
DO - https://doi.org/10.1039/D3RA02020G
SN - 2046-2069
VL - 13
IS - 21
SP - 14473
EP - 14483
PB - RSC Publishing
CY - London
AN - OPUS4-57453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gawek, Marcel
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Growth kinetics of the adsorbed layer of poly(2-vinylpyridine) - An indirect observation of desorption of polymers from substrates
N2 - The growth kinetics of the adsorbed layer of poly(2-vinylpiridine) on silicon oxide is studied using a leaching technique which is based on the Guiselin brushes approach. The adsorbed layer is grown from a 200 nm thick P2VP film for several annealing time periods at different annealing temperatures. Then the film is solvent-leached, and the height of the remaining adsorbed layer is measured by atomic force microscopy. At the lowest annealing temperature only a linear growth regime is observed, followed by a plateau. Here, the molecular mobility of segments is too low to allow for a logarithmic growth. At higher annealing temperatures, both linear and logarithmic growth regimes are observed, followed by a plateau. At even higher annealing temperatures, the growth kinetics of the adsorbed layer changes.
A linear growth followed by logarithmic growth kinetics is observed for short annealing time periods. For longer annealing time periods, an upturn of the growth kinetics is observed. At the highest annealing temperature, only a logarithmic growth regime is found. The change in the growth kinetics is discussed by an alteration in the structure of the adsorbed layer. Moreover, the interaction between the polymer segments and the substrate becomes weaker due to both enthalpic and entropic effects. Therefore, at high annealing temperatures the polymer segments might more easily desorb from the substrate.
KW - Ultra thin polymer films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575423
DO - https://doi.org/10.1039/d3sm00129f
SN - 1744-683X
SN - 1744-6848
VL - 19
IS - 21
SP - 3975
EP - 3982
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-57542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Pauw, Brian Richard
A1 - Qu, Xintong
A1 - Schönhals, Andreas
T1 - Competition of nanoparticle-induced mobilization and immobilization effects on segmental dynamics of an epoxy-based nanocomposite
N2 - The complex effects of nanoparticles on a thermosetting material based on an anhydride cured DGEBA/Boehmite nanocomposite with different particle concentrations is considered. A combination of X-ray scattering, calorimetry, including fast scanning calorimetry as well as temperature modulated calorimetry and dielectric spectroscopy, was employed to study the structure, the vitrification kinetics and the molecular dynamics of the nanocomposites. For the first time in the literature for an epoxy-based composite a detailed analysis of the X-ray data was carried out. Moreover, the unfilled polymer was found to be intrinsically heterogeneous, showing regions with different crosslinking density, indicated by two separate dynamic glass transitions. The glass transition temperature decreases with increasing nanoparticle concentration, resulting from a change in the crosslinking density. Moreover, on the one hand, for nanocomposites the incorporation of nanofiller increased the number of mobile segments for low nanoparticle concentrations, due to the altered crosslinking density. On the other hand, for higher loading degrees the number of mobile segments decreased, resulting from the formation of an immobilized interphase (RAF). The simultaneous mobilization and immobilization of the segmental dynamics cannot be separated unambiguously. Taking the sample with highest number of mobile segments as reference state it was possible to estimate the amount of RAF.
KW - Nanocomposite
PY - 2020
DO - https://doi.org/10.1039/d0sm00744g
SN - 1744-683X
VL - 16
IS - 23
SP - 5406
EP - 5421
PB - Royal Chemical Society
AN - OPUS4-50883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elsayed, M.
A1 - Abdel-Wakil, W. S.
A1 - Ghazy, M. B.
A1 - Fahmy, Alaa
T1 - Evaluating the performance of biopolyol-based rigid foams derived from rice straw liquefaction
N2 - Purpose
The polyurethane sector primarily relies on petrochemical substances, including polyols and isocyanates. Given the swift consumption of fossil fuel resources and the rising concerns about ecological issues and global warming, this study aims to explore the sustainable advancement of polyurethane rigid foam by using renewable biopolyols derived from agricultural waste liquefaction.
Design/methodology/approach
The liquefaction of lignocellulosic biomass involves breaking down complex polymers into smaller molecules using heat, chemicals and catalysts to prepare biopolyol as a renewable feedstock for the polyurethane industry. Spectral analysis of the liquefaction products verified that the process achieved the desired outcome and indicated the presence of hydroxyl groups. The biopolyol analysis demonstrated a biomass conversion rate of up to 87% and a hydroxyl number between 230 and 250 mg KOH/g, suggesting that this biopolyol could serve as a viable alternative to petrochemical polyols.
Findings
Various formulations of biopolyol obtained from rice straw liquefaction, conducted at 160 °C for 2 h, were prepared. Intensive study was conducted on the applicability of using biopolyol in rigid foam refrigerator formulation in comparison to petroleum counterparts. The results obtained from scanning electron microscopy showed that the biopolyol-based foams had a symmetrical cell structure and a significant proportion of sealed cells. Biobased foam demonstrated superior thermal insulation compared to its petrochemical-based equivalent.
Originality/value
These results underscore the feasibility of agricultural waste liquefaction as an eco-friendly approach for synthesizing biopolyols and their application in polyurethane foam production. The study contributes to the development of sustainable materials in the polymer industry and supports the transition toward renewable feedstocks in rigid foam applications. The study, moreover, introduces PEG 400 as a novel liquefaction solvent, offering improved compatibility with rigid polyurethane systems and establishing a new benchmark for sustainable rigid foam production.
KW - Bio-polyurethane
KW - Rice straw polyol
KW - Sustainable foams
KW - Bio-composites
KW - Biomass liquefaction
PY - 2026
DO - https://doi.org/10.1108/PRT-10-2025-0113
SN - 0369-9420
SP - 1
EP - 10
PB - Emerald
CY - Bingley
AN - OPUS4-65851
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Senbill, Haytham
A1 - Gangan, Amr
A1 - Saeed, Ahmed M.
A1 - Gad, Mohammed E.
A1 - Zeb, Jehan
A1 - Fahmy, Alaa
T1 - Effects of copper/graphene oxide core-shell nanoparticles on Rhipicephalus ticks and their detoxification enzymes
N2 - Nanopesticides have been recently introduced as novel pesticides to overcome the drawbacks of using traditional synthetic pesticides. The present study evaluated the acaricidal activity of Copper/Graphene oxide core-shell nanoparticles against two tick species, Rhipicephalus rutilus and Rhipicephalus turanicus. The Copper/Graphene oxide core-shell nanoparticles were synthetized through the solution plasma (SP) method under different conditions. The nanoparticles synthesized at 180 W and 45 min were highly toxic to Rh. rutilus and Rh. turanicus, with 50% lethal concentration (LC50) values of 248.1 and 195.7 mg ml−1, respectively, followed by those which were synthesized at 120 W/30 mins (LC50 = 581.5 and 526.5 mg ml−1), 120 W/15 mins (LC50 = 606.9 and 686.7 mg ml−1), and 100/45 mins (LC50 = 792.9 and 710.7 mg ml−1), after 24 h of application. The enzyme assays revealed that 180 W/45 min treatment significantly inhibited the activity of acetylcholinesterase (115 ± 0.81 and 123 ± 0.33 U/ mg protein/min) and superoxide dismutase (290 ± 0.18 and 310 ± 0.92 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively, as compared with the negative control. The results also revealed a significantly increased catalase activity (895 ± 0.37 and 870 ± 0.31 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively. The above results indicated that Copper/Graphene oxide core-shell nanoparticles could be a promising alternatives for the management of ticks.
KW - Copper/graphene oxide
KW - Nanopesticides
KW - Rhipicephalus rutilus
KW - Rhipicephalus turanicus
KW - Acetylcholinesterase
KW - Antioxidants
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629359
DO - https://doi.org/10.1038/s41598-025-86560-4
SN - 2045-2322
VL - 15
SP - 1
EP - 12
PB - Springer Nature
CY - London
AN - OPUS4-62935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saeed, A. M.
A1 - Saied, M. A.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
A1 - Fahmy, Alaa
T1 - High performance novel polyelectrolyte membrane consisting of polyvinyl alcohol-phenylsilanol-polypyrrole
N2 - The synthesis of composite membranes based on PVA, PPy, and sulfonated–hydrolyzed TMPS was investigated for application in proton–exchange membrane fuel cells. FT–IR confirmed the hydrolysis of TMPS through the appearance of Si–OH vibrations, disappearance of Si–O–CH3 bands, reduced CH3 stretching intensity (2840 cm− 1), and successful sulfonation of the phenyl ring (1030 cm− 1). XPS verified the introduction of sulfonic acid groups by identifying S2p peaks between 166–170 eV. Scanning electron microscopy (SEM) showed an incorporation of PPy and that the membrane morphology altered by silanol leading to an increased surface roughness and inducing phase separation in comparison to pure PVA. The PVA–PPy–Si membrane which did not undergo phase separation demonstrated improved mechanical stability (maximum stress 5.91 MPa), reduced methanol uptake (22%, lower than Nafion’s 30%), and enhanced thermal resistance compared to PVA–PPy and PVA–Si. It also exhibited a high ion–exchange capacity (1.5mmol g− 1, exceeding Nafion® at 0.9mmol g− 1 ) and a proton conductivity of 0.036 S/cm, twice that of Nafion 117. These combined properties identify the PVA–PPy–Si composite as a promising high–performance polyelectrolyte membrane for fuel cell applications.
KW - Polyelectrolyte membrane
PY - 2026
DO - https://doi.org/10.1016/j.apsusc.2026.166495
SN - 1873-5584
VL - 731
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-65627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Adham-Zomrawy, A.
A1 - Saeed, A. M.
A1 - El-Arab, M. A. E.
A1 - Shehata, H.
A1 - Friedrich, J.
T1 - Degradation of organic dye using plasma discharge: optimization, pH and energy
N2 - Decolorization of Acid Orange 142 (AO142) as important water pollutant was observed on the exposure of the dye solutions to an atmospheric non-thermal gas plasma. Aresponse Surface methodology (RSM) combined with a central composite design (CCD) was utilized to optimize the main factors (variables) affecting the degradation efficiency (response) of AO142, such as the applied voltage, the gap distance between the high voltage electrode and the surface of the solution. The regression analysis showed that a first-order polynomial model well fits the experimental data with a coefficient of determination R2=0.96. FT-IR, UV-vis,TOCand GC-MS measurements were used to investigate the decolorization of the dye on exposure to the plasma discharges. A possible Degradation pathway was postulated. Additionally, the conductivity and pH changes during the treatment were also evaluated. The plasma treatment combined with Fe2+ (plasma Fenton reaction) exhibited a higher degradation efficiency, higher energy yield connected with lower energy consumption in comparison to the plasma treatment without Fe2+ addition.
KW - Advanced Oxidation
PY - 2020
DO - https://doi.org/10.1088/2516-1067/ab6703
VL - 2
IS - 1
SP - 015009
PB - IOP publishing Ltd
AN - OPUS4-50467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kamoun, E.
A1 - Afifi, K.
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Fahmy, Alaa
T1 - Structure-property relationship of cross-linked chitosan-ethyl cellulose membranes
N2 - Intensive research is focused on creating cost-effective, high-performance polyelectrolyte membranes (PEMs) for electrochemical devices designed to generate and/or store electrical energy. On the other hand, biopolymer materials have been utilized in a wide range of applications across medical and engineering fields, as well as in the textile and energy sectors. Therefore, in this study, chemically cross-linked chito-san/ethyl cellulose-citric acid (CS-EC-CA) membranes were prepared by a casting technique. The structure-property relationship of CS-EC/CA has been discussed based on the molar ratio of CS. The structural properties of the resultant membrane were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy, thermal stability was assessed using thermogravimetric analysis.
Moreover, the ion exchange capacity (IEC) and water uptake of the membrane were studied. FTIR analysis revealed a significant broadening of absorption peaks in the range of 3200–3500 cm-1 , corresponding to -OH groups, presence of CA. A new peak at 1725 cm-1 confirmed the formation of chemical linkages between CA and CS-EC. The results of the thermal analysis revealed that a thermally stable membrane was obtained when it was chemically cross-linked compared to non-cross-linked membranes. The IEC values of the modified membranes were enhanced significantly, increasing from 0.08 mmol/g for pure CS to 0.5 mmol/g for CS (50%) and 0.8 mmol/g for CS (50%) cross-linked withCA. Furthermore, the cross-linked membranes demonstrated the lowest water and ethanol uptake values, emphasizing their suitability for fuel cell applications.
KW - Polyelectrolyte membranes
PY - 2025
DO - https://doi.org/10.1063/5.0279022
SN - 1089-7666
VL - 37
IS - 8
SP - 1
EP - 11
PB - AIP Publishing
AN - OPUS4-63890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - El Sabbagh, M.
A1 - Bedair, M.
A1 - Gangan, A.
A1 - El-Sabbah, M.
A1 - El-Bahy, S.
A1 - Friedrich, J.
T1 - One-step plasma deposited thin SiOxCy films for corrosion resistance of low carbon steel
N2 - Tetraethyl orthosilicate (TEOS) was used as a chemical precursor to deposit ultra-thin SiO x C y plasma polymer films onto mild steel surfaces for preventing the corrosion process. The structure–property relationships of the coatings were evaluated by X-ray Photo Spectroscopy (XPS), X-Ray Diffraction (XRD), Fourier Transform InfraRed spectroscopy (ATR-FTIR) and Energy Dispersive X-ray spectroscopy (EDX) completed with Scanning Electron Microscopy (SEM). The SEM micrographs confirmed a pinhole-free surface morphology of the low-pressure deposited plasma polymer films. The TEOS molecules become fragmented in the plasma by numerous collisions with energy-rich electrons and heavier particles. Recombination of fragments and condensation onto the steel substrate is responsible for the formation of organic SiO containing plasma polymer layers. Such thin layers consist of predominantly SiO x structures. Their properties are determined largely by the gap distance between the two samples used as electrodes in the plasma. The efficiency of the corrosion-protecting coating was compared with uncoated samples. The corrosion protection was determined by exposure of samples to 3.5% NaCl aqueous solutions. For this purpose, polarization and Electrochemical Impedance Spectroscopy (EIS) were used to monitor the corrosion. The optimal gap distance between the electrodes was determined for corrosion protection. The best protective efficiency reached more than 97% of the total protection as measured at room temperature.
KW - Thin films
KW - Corrosion resistance
KW - Mild steel
KW - Plasma treatments
KW - Tetraethyl orthosilicate
PY - 2020
DO - https://doi.org/10.1080/01694243.2020.1856539
VL - 35
IS - 16
SP - 1734
EP - 1751
PB - Taylor & Francis
AN - OPUS4-52303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hernández García, María Amparo
T1 - Characterization and testing of commercial photo-resins for the fabrication of free-form optical elements with standard LCD 3D printer for advanced opto-biosensing applications
N2 - Optical biosensors often show remarkable performance and can be configured in many ways for sensitive, selective, and rapid measurements. However, the high-quality and advanced optical assemblies required to read out the sensor signals, for example, Total Internal Reflection Fluorescence (TIRF) or Supercritical Angle Fluorescence (SAF) microscopy, which necessitate complex and expensive optical elements. Particularly in optical method development, researchers or developers are often confronted with limitations because conventional manufacturing processes for optical elements can be restrictive in terms of design, material, time, and cost. Modern and high-resolution 3D printing techniques make it possible to overcome these challenges and enable the fabrication of individualized and personalized free-form optical components, which can reduce costs and significantly shorten the prototyping timeline—from months to hours. In this work, we use a modern, high-resolution (< 22 µm) commercial Liquid Crystal Display (LCD)-based 3D printer, for which we spectroscopically and physically characterized commercial photo-resins printable with the LCD technique in the first step (Figure 1). The aim was not only to produce a printed element with a high surface quality that mitigates the inner filter effects caused by attenuation (high optical density (OD) due to reflection and scattering), but also to select a material with a high refractive index (RI>1.5) and high transmission values (>90% transmittance) in the visible to near-infrared spectral range (approx. 450 – 900 nm) that exhibits little or no autofluorescence. Using a selection of suitable resins, lenses and free-form optical elements were manufactured for comparison with standard glass or plastic counterparts.
T2 - Europt(r)ode XVI
CY - Birmingham, England
DA - 24.03.2024
KW - 3D-printing
KW - Optics
KW - Photopolymerization
KW - Sensors
KW - Rapid prototyping
PY - 2024
AN - OPUS4-59875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kanerva, M.
A1 - Matrenichev, V.
A1 - Layer, R.
A1 - Takala, T. M.
A1 - Laurikainen, P.
A1 - Sarlin, E.
A1 - Elert, Anna Maria
A1 - Yuding, V.
A1 - Seitsonen, J.
A1 - Ruokolainen, J.
A1 - Saris, P.
T1 - Comparison of Rosin and Propolis Antimicrobials in Cellulose Acetate Fibers Against Staphylococcus aureus
N2 - The quantitative difference in the antibacterial response was measured for pine rosin and propolis against Staphylococcus aureus ATCC 12598. The activity was studied for fibrous networks that form entirely bio-based cellulose-acetate (CA) materials. The analysis considers the effects of bacterial input, additive dosage, solvent type, variation in preparation, as well as the effect of storage time. Based on the results, the electrospun network structure is dependent on the solvent and the concentration of rosin and propolis. Both rosin and propolis improved the cellulose acetate solution processability, yet they formed beads at high concentrations. Rosin and propolis created strong antibacterial properties when these material systems were immersed in the liquid for 24 h at room temperature. The response remained visible for a minimum of two months. The electrospun networks of water and DMAc solvent systems with 1 to 5 wt% rosin content were clearly more efficient (i.e., decrease of 4 to 6 logs in colony forming units per mL) than the propolis networks, even after two months. This efficiency is likely due to the high content of abietic acids present in the rosin, which is based on the Fourier transform infrared spectra. The results of the additional analysis and cell cultivation with dermal fibroblast cells indicated an impairing effect on skin tissue by the rosin at a 1 wt% concentration compared to the pure CA fibers.
KW - Electrospinning
KW - Rosin
KW - Propolis
KW - Antibacterial
KW - Cellulose acetate
PY - 2020
SN - 1930-2126
VL - 15
IS - 2
SP - 3756
EP - 3773
AN - OPUS4-50635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
T1 - Invesitgation of Thin Film Interactions with Inorganic Surfaces
N2 - Thin polymer films are of vital importance due to their low production costs and wide range of applications in sensors, electronics, and coatings. Their geometry is ideal for the study of confinement effects, specifically one-dimensional confinement, on the thermodynamic properties and segmental dynamics of polymers. For this investigation, films of PC are prepared on both glass and silica substrates to measure the dielectric and calorimetric behavior as a function of film thickness. The methodology consists of broadband dielectric spectroscopy (BDS), ellipsometry, and atomic force microscopy (AFM). Using ellipsometry, the glass transition shows an increase with decreasing film thickness. Compared to a previous investigation of PC where dilatometry was used, an increase in PC was seen, but now only at thicknesses below 20 nm. Therefore, the critical thickness of PC, where the bulk-like layer no longer percolates through the film, is dependent on the method probing the glass transition. The dielectric behavior shows a deviation from bulk behavior with decreasing film thickness, although still showing a Vogel-Fulcher-Tammann (VFT) temperature dependence for all films. The influence of the adsorbed layer on the molecular mobility was also addressed.
T2 - Deutschen Physikalische Gesellschaft (DPG) Tagung
CY - Regensburg, Germany
DA - 04.09.2022
KW - Thin films
KW - Adsorbed Layer
KW - Broadband dielectric spectroscopy
PY - 2022
AN - OPUS4-55706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Topolniak, Ievgeniia
A1 - Elert, Anna Maria
A1 - Knigge, Xenia
A1 - Cifci, G. C.
A1 - Radnik, Jörg
A1 - Sturm, Heinz
T1 - Polydopamine micropatterning for selective substrate bio-functionalization
N2 - Inspired by the chemistry of mussel adhesive proteins, polydopamine (PDA) exhibits strong adhesion to nearly any kind of organic or inorganic surface and shows high ability for surface post-modification and secondary reactions. As a result, PDA has been widely used as a base adlayer to enable versatile surface chemistry and functionalization. It has shown great potential in wide range of applications including biomedical field (e.g., drug delivery, adhesives, photothermal therapy, bone and tissue engineering, cell adhesion, biosensing). However, implementation of PDA in microdevices is still hindered by insufficient spatial and temporal control of excited deposition methods.
In this work we present a novel approach to fabricate tunable micropatterned substrates where mussel-inspired chemistry provides base for various surface modification [2]. Current approach applies Multiphoton Lithography (MPL) to initiate local PDA formation, and, therefore, does not require use of microstamp or photomask. As a result, the microstructures of complex designs can be produced with the spatial resolution down to 0.8 μm (Figure 1). The desired design can be easily altered by adjusting the stl model or the fabrication code. Unlike the conventional deposition of PDA based on dopamine auto-oxidation, our method does not require presence of strong oxidants, metal ions or alkaline pH. Herein-demonstrated deposition approach will significantly facilitate applications of polydopamine and other mussel-inspired materials in microdevices and high-resolution active microcomponents (e.g., in MEMS and microfluidics).
Adjustment of MPL parameters revealed that the morphology and thickness of resulted PDA microstructures can be controlled by altering the laser power and its scanning velocity. As a result, it also enables the production of micropatterns with structural gradient. Apart from the glass substrate, we performed PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips. We tested different composition of dopamine solution for its ability of PDA buildup. Solutions containing Tris buffer, phosphate buffer or DI water only as well as different pH (6.0, 7.0 and 8.5) could be successfully applied for high-precision PDA micropatterning. Moreover, the effect of antioxidants and purging of the solution with oxygen and nitrogen was investigated. In all cases, no decrease of deposition efficiency was observed. The chemical nature of PDA was confirmed by locally recorded vibrational and x-ray photoelectron spectra. To ensure post-modification potential of MPL deposited PDA we demonstrated one-step deposition of micropatterns with trypsin. Obtained bio-functionalised surface can be further applied as a protein sensing active microelement.
T2 - Laser Precision Microfabrication
CY - Dresden, Germany
DA - 07.06.2022
KW - Polydopamine
KW - Two-photon polymerisation
KW - Micropatterning
PY - 2022
AN - OPUS4-55064
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Böhning, Martin
A1 - Frick, B.
A1 - Apple, M.
A1 - Mole, R. A.
A1 - De Souza, N. R.
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Confined Segmental Diffusion in Nanophase Separated Janus Polynorbornenes as Investigated by Quasielastic Neutron Scattering
N2 - A combination of neutron time-of-flight and neutron backscattering spectroscopy was used to investigate the molecular dynamics of Janus polynorbornenes (Janus poly(tricyclononenes)) on a microscopic level.
These Janus polynorbornenes, denoted as PTCNSiOR, have a semirigid backbone with −Si(OR)3 side groups attached to it. R represents the length of the alkyl side chain. Here side chain lengths of R = 3 (propyl) and R = 8 (octyl) were considered. It is worth mentioning that these polymers have some potential as active layers in gas separation membranes, especially for the separation of higher hydrocarbons. The combination of time-of-flight and backscattering will ensure a reasonably broad time window for analysis where the incoherent intermediate scattering function SInc(q,t) is considered. Previously, it was shown by X-ray investigations that the system undergoes a nanophase separation into alkyl side chain-rich domains surrounded by a backbone-rich matrix. For PTCNSiOPr (R = 3), the alkyl side-chain-rich domains are truly isolated in the backbone-rich matrix, whereas for PTCNSiOOc (R = 8) these domains percolate through the matrix. Further, it was also previously shown that the alkyl side-chain-rich domains undergo a glass transition. The advantage of neutron scattering experiments discussed here is that besides temporal also spatial information is obtained which will allow conclusions to be drawn about the type of molecular fluctuations. At the lowest measured temperature, the decay in Sinc(q,t) is due to the methyl group rotation. The methyl group dynamics is analyzed in terms of a modified jump-diffusion in a 3-fold potential and yields to a reasonable fraction of hydrogens which contribute to the methyl group rotation. At higher temperatures, the decay in SInc(q,t) is due to both the methyl group rotation and the segmental dynamics in the alkyl side-chain-rich domains. The segmental diffusion is modeled by a sublinear diffusion. For the analysis of the scattering function SInc(q,t) of PTCNSiOPr an elastic scattering due to the immobilized backbone-rich matrix must be taken into account. The analysis reveals that the segmental dynamics is confined by the finite size of alkyl chain-rich domains and that it is intrinsically heterogeneous in nature. Both effects are more pronounced for PTCNSiOPr in comparison to those of PTCNSiOOc.
KW - Polynorbornene
KW - Quasielastic Neutron Scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608712
DO - https://doi.org/10.1021/acs.macromol.4c01045
SP - 1
EP - 14
PB - ACS Publications
AN - OPUS4-60871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - The digital product passport
N2 - This presentation contains information for industry and the scientific communitiy about the new digital product passport and the demands from the EU. Furthermore a short overview is given about the different supporting activities which are currently under developement by BAM.
T2 - 3. Netzwerktag Cluster Nanotechnologie
CY - Würzburg, Germany
DA - 02.07.2025
KW - DPP
KW - ESPR
KW - Product Passport
KW - Ökodesignrichtlinie
KW - DMP
PY - 2025
AN - OPUS4-64964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Kolmangadi, Mohamed Aejaz
A1 - Bühlmeyer, A.
A1 - Huber, P.
A1 - Laschat, S.
A1 - Schönhals, Andreas
T1 - Electrical conductivity and multiple glassy dynamics of crow-ether based columnar liquid crystals
N2 - The phase behavior of two unsymmetrical triphenylene crown ether-based columnar liquid crystals (CLCs) bearing different lengths of alkyl chains, KAL465 and KAL468, was investigated using differential scanning calorimetry (DSC). A plastic crystalline (Cry), columnar liquid crystalline (Colh) and an isotropic phase were observed along with two glass transitions in the Cry phase. The molecular mobility of the KAL compounds was further studied by a combination of broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques. By the BDS investigations, three dielectric active relaxation processes were observed for both samples. At low temperatures, a γ-process in the Cry state was detected and is assigned to the localized fluctuations taking place in the alkyl chains. An α2-process takes place at higher temperatures in the Cry phase. An α3 process was found in the Colh mesophase. The advanced calorimetric techniques consist of fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS) employing temperature modulated DSC and FSC (TMDSC and TMFSC). The advanced calorimetric investigations revealed that besides the α2 process in agreement with BDS, a second dynamic glass transition (α1-process) is present which is not observed by dielectric spectroscopy. The results are in good agreement with the glass transitions detected by DSC for this process. The temperature dependences of the relaxation rates of the α1 , α2 and α3 processes are all different. Therefore, different molecular assignments for the relaxation processes are proposed. In addition to the relaxation processes, a conductivity contribution was explored by BDS for both KAL compounds. The conductivity contribution appears in both Cry and Colh phases, where the conductivity increases by ca. one order of magnitude at phase transition from the crystalline to the hexagonal phase.
KW - Columnar Liquid Crystal
PY - 2020
DO - https://doi.org/10.1021/acs.jpcb.0c06854
VL - 124
IS - 39
SP - 8728
EP - 8739
PB - ACS
AN - OPUS4-51374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hertwig, Andreas
T1 - Determining thermal transitions in thin polymer layers by means of spectroscopic ellipsometry
N2 - Thin polymer layers have enormous technical significance as polymer coatings on materials are very cost-effective for tailoring properties of surfaces. Apart from technical aspects in their use, thin polymer layers can be used to determine dimensional aspects in properties of material, such as confinement effects.
In this work, we investigated several different polymer layer materials and determined their glass transition region by means of temperature-dependent spectroscopic ellipsometry. We have optimised our fitting procedure of the ellipsometric data produced in temperature ramp experiments. By this, we could measure the dependence of Tg on the layer thickness in a wide variety of thickness values, proving the existence of confinement effects in the investigated systems. We compare numerical methods for determining the location of the glass transition and discuss the possibilities of different analysis methods when determining thermal transitions. We also discuss the simultaneous existence of these transitions and annealing effects and the implications on the accuracy of the determined data.
T2 - 12th Workshop Ellipsometry 2023
CY - Prague, Czech Republic
DA - 18.09.2023
KW - Thin Films
KW - Polymers
KW - Ellipsometry
KW - Themal Transitions
PY - 2023
AN - OPUS4-58413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy-based Materials
N2 - This work deals with an in-depth comparative investigation of the structure, molecular mobility and vitrification kinetics of three bisphenol A diglycidyl ether (DGEBA)-based materials with different nanofillers: taurine-modified layered double hydroxide (T-LDH) and halloysite nanotubes (HNTs). The chosen methodology comprises I) small – and wide – angle X-ray scattering (SAXS/WAXS) II) calorimetry in the forms of a) conventional DSC and b) static fast scanning calorimetry (FSC), III) broadband dielectric spectroscopy (BDS), as well as IV) specific heat spectroscopy in the forms of a) temperature modulated DSC, and b) temperature modulated FSC.
T2 - Abteilungsseminar 6. - FB 6.6
CY - Online meeting
DA - 06.05.2021
KW - Broadband dielectric spectroscopy
KW - Epoxy nanocomposites
KW - Halloysite nanotubes
KW - X-ray scattering
KW - Differential scanning calorimetry
KW - Rigid amorphous fraction
KW - Flash DSC
PY - 2021
AN - OPUS4-52697
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Inelastic and Quasielastic Neutron Scattering Experiments on Mircroporous Membranes for Green Separation processes
N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. These polymers are characterized by a high permeability and reasonable permselectivity. The latter point is somehow surprising because for microporous systems a more Knudson-like diffusion is expected then a size dependent temperature activated sieving process. It was argued in the framework of a random gate model that molecular fluctuations on a time scale from ps to ns are responsible for the permselectivity.
Her a series of microporous polynorbornenes with bulky Si side groups and a rigid backbone are considered which have different microporosity characterized by BET surface area values.
First inelastic time-of-flight neutron scattering measurements were carried out to investigate the low frequency density of state (VDOS). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. It was found the maximum position of the Boson peak correlates with the BET surface area value.
For two selected comparable polynorbornenes elastic scans as well as QENS measurements by a combination of neutron time-of-flight and backscattering are carried out. A low temperature relaxation process was found for both polymers. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized.
T2 - MLZ Conference 2022: Neutrons for mobility
CY - Lengries, Germany
DA - 31.05.2022
KW - Polymers of intrinsic Microporosity
PY - 2022
AN - OPUS4-55674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
A1 - Omar, Hassan
A1 - Gawek, Marcel
A1 - Hertwik, Andreas
A1 - Madkour, Sherif
A1 - Schönhals, Andreas
T1 - Investigation of the behavior of thin polymeric films including the adsorbed layer on the substrate by nano-sized relaxation spectroscopy and complementary methods
N2 - Thin polymeric films are of great importance of high number of high-tech applications for instance in sensors and nanoelectronics. Form the scientific point of view thin films with thickness below 100 nm are ideal model systems to study confinement effects on its properties for instance on the molecular relaxation processes. In this contribution an overview is presented about the behavior of different systems as investigated by nanosized relaxation spectroscopy like broadband dielectric spectroscopy employing nano structured capacitors and AC chip calorimetry complimented by ellipsometry. The systems considered are PVME1, PVME/PS blends2,3 P2VP4, PBAC5 and polysulfone6. Besides the film also the adsorbed layer on the substrate prepared by a leaching approach and investigated by AFM is considered.1,4-7. For these investigationsss it is found that the adsorbed layer itself exhibits a relaxation dynamics which might be assigned either to molecular motions or to adsorptions desorption kinetics.
T2 - 9. International Discussion Meeting Relaxation Complex Systems
CY - Chiba, Japan
DA - 12.08.2023
KW - Thin polymer films
PY - 2023
AN - OPUS4-58103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Schönhals, Andreas
T1 - Application of Fast Scanning Calorimetry in Soft Matter Research – Two Examples: 1. Polymers for Gas separation membranes 2. Ionic Liquid Crystals
N2 - The application of fast scanning calorimetry (FSC) with heating rates in the range from 10 K/s to 10,000 K/s in soft matter research is discussed through two examples. In the first part, FSC is applied to polymers of intrinsic microporosity (PIMs). No glass transition could be measured for these polymers by conventional calorimetry before their degradation. By decoupling the time scales of chemical degradation and the glass transition, it could be shown for the first time that PIMs undergo a glass transition. In the second part, FSC is applied to ionic liquid crystals to investigate their molecular mobility. In order to cover a broad dynamical range, FSC is combined with temperature-modulated differential scanning calorimetry, and temperature-modulated FSC.
T2 - Colloqium at the physics department of the Charles university Prague
CY - Prague, Czech Republic
DA - 12.11.2024
KW - Fast Scanning Calorimetry
PY - 2024
AN - OPUS4-61670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Wolf, M.
A1 - Alentiev, D.
A1 - Bermeshev, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Low frequency vibrational density of state of highly permeable super glassy polynorbornenes – The Boson peak
N2 - Inelastic incoherent neutron time-of flight scattering was employed to measure the low frequency density of states for a series of addition polynorbornenes with bulky side groups. The rigid main chain in combination with the bulky side groups give rise to a microporosity of these polymers in the solid state. The microporosity characterized by the BET surfaces area varies systematically in the considered series. Such materials have some possible application as active separation layer in gas separation membranes.
All investigated materials show excess contributions to the Debye type density of states characteristic for glasses known as Boson peak. The maximum position of the Boson peak shifts to lower frequency values with increasing microporosity. Data for PIM-1 and Matrimid included for comparison are in good agreement to this dependency. This result supports the sound wave interpretation of the Boson peak.
KW - Polynorbornes
KW - Neutron Scattering
PY - 2020
DO - https://doi.org/10.1039/d0cp03360j
SN - 1463-9076
VL - 22
IS - 33
SP - 18381
EP - 18387
PB - Royal Chemical Society
AN - OPUS4-51165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Malpass-Evans, R.
A1 - McKeown, N.
A1 - Tyagi, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Low frequency vibrations and diffusion in disordered polymers bearing an intrinsic microporosity as revealed by neutron scattering
N2 - The microscopic diffusion and the low frequency density of states (VDOS) of PIM-EATB(CH3) are investigated by inelastic and quasi-elastic neutron scattering where also the demethylated counterpart of PIM-EA-TB(H2) is considered. These intrinsic microporous polymers are characterized by large BET surface area values of several hundred m2/g and pore sizes between 0.5 and 2 nm. Detailed comparison is made to the archetype of polymers of intrinsic microporosity, PIM-1, and polynorbornenes also bearing a microporosity. Due to the wavelength of neutrons, the diffusion and vibrations can be addressed on microscopic length and time scales. From the inelastic neutron scattering experiments the low frequency density of states (VDOS) is estimated which shows excess contributions to the Debye-type VDOS known as Boson peak. It was found that the maximum frequency of the Boson peak decreases with increasing microporosity characterized by the BET surface area. However, besides the BET surface area, additional factors such as the backbone stiffness govern the maximum frequency of the Boson peak. Further the mean squared displacement related to microscopic motions was estimated from elastic fixed window scans. At temperatures above 175 K, the mean squared displacement PIM-EA-TB(CH3) is higher than that for the demethylated counterpart PIM-EA-TB(H2). The additional contribution found for PIM-EATB(CH3) is ascribed to the rotation of the methyl group in this polymer because the only difference between the two structures is that PIM-EA-TB(CH3) has methyl groups where PIM-EA-TB(H2) has none. A detailed comparison of the molecular dynamics is also made to that of PIM-1 and the microporous polynorbornene PTCNSi1. The manuscript focuses on the importance of vibrations and the localized molecular mobility characterized by the microscopic diffusion on the gas Transport in polymeric separation membranes. In the frame of the random gate model localized fluctuations can open or close bottlenecks between pores to enable the diffusion of gas molecules.
KW - Polymer of intrisic microporosity
KW - Neutron scattering
KW - Boson peak
KW - Methyl group rotation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538490
DO - https://doi.org/10.3390/cryst11121482
VL - 11
IS - 12
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed Aejaz
A1 - Szymoniak, Paulina
A1 - Smales, Glen Jacob
A1 - Bermeshev, M.
A1 - Schönhals, Andreas
A1 - Böhning, Martin
T1 - Molecular mobility of polynorbornenes with trimethylsiloxysilyl side groups: Influence of the polymerization mechanism
N2 - We report dielectric and calorimetric studies on metathesis and addition-type polytricyclononenes, both based on the same monomer bearing three pendant OSiMe3 groups. For the addition-type polymer, dielectric spectroscopy reveals a β*-process related to the microporosity, whereas for its metathesis counterpart, the segmental dynamics manifests as an α-process related to a glass transition. Besides active dielectric processes, a significant conductivity contribution is detected for both samples which for the microporous additiontype polymer is three orders of magnitude greater than for the metathesis polymer. The broadband dielectric spectroscopy is complemented by detailed calorimetric investigations, comprising DSC, FSC, and TMDSC. The calorimetric methods detected the glass transition for the metathesis polymer in agreement with the observed dielectric α-process. Furthermore, the already reported gas transport properties for both polymers are compared, setting them in correlation with the observed molecular mobility and conductivity behavior. The discussed results reflect significant differences in molecular mobility of the two polymers affecting the appearance of microporosity which strongly determines the gas transport properties.
KW - Microporous polymers
KW - Molecular mobility
KW - Electrical conductivity
KW - Membrane polymers
KW - Gas separation
PY - 2022
DO - https://doi.org/10.22079/JMSR.2021.538060.1495
SN - 2476-5406
VL - 8
IS - 3
SP - 1
EP - 9
PB - Membrane Processes Research Laboratory (MPRL)
CY - Tehran
AN - OPUS4-54303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Riechers, Birte
A1 - Maaß, Robert
A1 - Michalchuk, Adam
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Beyond conventional calorimetry: Unlocking thermal characterization with fast scanning techniques
N2 - Fast scanning calorimetry (FSC) has emerged as a transformative technique in thermal analysis, enabling the investigation of rapid and kinetically driven thermal transitions that are inaccessible to conventional differential scanning calorimetry. This review highlights the capabilities enabled by FSC for studying a wide range of materials under extreme thermal conditions, including polymers, pharmaceuticals, metallic glasses, nanocomposites, and hydrogels. By employing ultrafast heating and cooling rates, FSC allows for the suppression of crystallization, resolution of weak transitions, and analysis of thermally labile or size-limited samples. The technique is particularly valuable for probing glass transitions, relaxation phenomena, and phase behavior in systems with complex morphologies or confined geometries. Case studies demonstrate the use of FSC in characterizing vitrification, physical aging, and interfacial dynamics, as well as its application in emerging fields such as additive manufacturing, supramolecular systems, and neuromorphic materials. Together, these examples underscore the role that FSC plays in advancing the understanding of structure-property relationships across diverse material classes.
KW - Flash DSC
KW - Calorimetry
KW - Glass transition
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647405
DO - https://doi.org/10.1016/j.tca.2025.180177
VL - 754
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-64740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy and Corresponding Nanocomposites by Broadband Dielectric Spectroscopy and Hyphenated Calorimetry
N2 - Polymer nanocomposites (PNCs) with inorganic nanofillers dispersed in a polymer matrix have been widely studied from the 1990s, since the pioneering work by Toyota Central Research. The possibility of producing advanced tailor-made, light weight and low-cost materials, inspired academic and commercial research towards numerous potential applications, facilitating PNCs to become a billion-dollar global industry. The introduction of nanoparticles (NPs) to a polymer matrix is expected to result in improved properties. The outstanding performance of PNCs is determined not only by the characteristics of the used components but also by their phase morphology, including the dispersion of NPs and interfacial properties. Understanding of structure-property relationships is particularly important for polymer nanocomposites with high industrial significance, such as epoxy-based materials reinforced with inorganic nanofillers. These PNCs have been successfully adopted by the marine, automotive and aerospace industries, although they are still rarely studied on a fundamental level. Therefore, this thesis aims for a detailed understanding of the structure, molecular mobility and vitrification kinetics first, of two epoxy-based materials with different network structures and second, of the corresponding nanocomposites with different alumina-based nanofillers. The first system considered (EP/T-LDH) was based on bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) and taurine-modified layered double hydroxide (T-LDH) NPs. The taurine molecule bears additional functionalities that could enhance the interactions between the matrix and the nanofiller, improving the interphase formation. The seconds system (EP/BNP) was based on DGEBA and methyl tetrahydrophtalic acid anhydride (MTHPA) as a hardener, reinforced with boehmite nanoparticles (BNPs). The comparison of the two systems enables for a comparative study on the effect of different hardeners and the morphology and modification of the alumina-based nanofillers on the material behavior. The materials were investigated employing complementary techniques with different sensitivities and frequency windows. The following methodology was used: transmission electron microscopy (TEM), small – and wide – angle X-ray scattering (SAXS/WAXS), broadband dielectric spectroscopy (BDS), calorimetry in a form of conventional DSC and fast scanning calorimetry (FSC), as well as specific heat spectroscopy (SHS) in a form of temperature modulated DSC, temperature modulated FSC and static FSC by calculating the thermal relaxation rates from the cooperativity approach. The FSC method (based on adiabatic chip calorimetry to probe micrometer-sized samples) was successfully employed in this work, exploiting all its possibilities for the first time in literature for a PNC. Moreover, a systematic analysis technique was established to overcome the problem of vague glass transition regions observed for highly loaded PNCs in the heat flow and heat capacity curves.
First, TEM, SAXS/WAXS and indirectly BDS and SHS were employed to obtain the information about the approximate morphology of the PNCs. It was found that epoxy-based materials exhibit a structural heterogeneity in a form of regions with different average crosslinking density. This was indicated by multiple-peak scattering pattern of the polymer matrix and two distinct α-processes (dynamic glass transition) related to the cooperative fluctuation of the epoxy network found by BDS and SHS. This was described for the first time for epoxy-based materials. The two α-relaxations were evidenced differently for the two systems, which is related to different network structures and dipole moments due to the employed hardeners. Nevertheless, structural heterogeneity is an intrinsic feature of these materials, independent of the type of hardener used for the network formation and nanofiller. In addition, matrix inhomogeneities were more pronounced with increasing nanoparticle content. Furthermore, a powerful new technique was applied for X-ray scattering data, using Monte Carlo fits, to describe the NPs dispersion throughout the whole sample volume (as opposed to the local investigations performed by most researches). Additional structural information of the two systems was extracted by BDS and SHS, such as qualitative and quantitative estimation of polymer segments physically adsorbed and/or chemically bonded onto the nanoparticles. Due to the immobilized character of this interphase with respect to the cooperative segmental motions, it is denoted as a rigid amorphous fraction (RAF). For instance, on the contrary to EP/BNP, for EP/T-LDH a dielectrically active process was found, related to the localized fluctuations within RAF. Moreover, the amount of RAF in EP/T-LDH was reaching up to 40 wt % of the system, whereas in EP/BNP it ranged between 1-7 wt %. In the latter case the presence of NPs was found to simultaneously increase and decrease the number of mobile segments, due to the interphase formation and changes in crosslinking density. The difference between the two systems was ascribed to the presence of additional amine functionalities in the T-LDH nanofiller.
Second, employing BDS and SHS, a systematic study on the effect of NPs on the segmental dynamics was performed. For example, depending on the nanofiller, the α-processes related to regions with higher crosslinking density was found to shift to higher and lower temperatures with increasing T-LDH and BNPs concentration, respectively. The observed difference is due to the different synergism of the polymer matrix with the nanofiller.
Third, a detailed investigation of the vitrification kinetics was performed with DSC and FSC. The concentration dependence of the glass transition temperature was found, similar to the behavior of the α-processes. It was shown that, in parallel to the detected main glass transition, epoxy-based materials can exhibit an additional low temperature vitrification mechanism. As expected from the two distinct α-processes, this behavior was however not discussed in prior studies for an unfilled network former. This finding was correlated to the structural heterogeneity evidenced by other techniques.
This thesis, dealing with an in-depth research on the epoxy-based materials that are already successfully employed in numerous applications underlines the necessity of more fundamental research in this field. It shines light on the complexity of these systems and contributes to defining how the structure-property relationships can be determined by combining multiple experimental techniques and analytical methodology.
T2 - PhD defense
CY - Online meeting
DA - 18.12.2020
KW - Interfaces
KW - Nanocomposites
KW - Rigid amorphous fraction
KW - TMDSC
KW - BDS
PY - 2020
AN - OPUS4-52035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Spatial Inhomogeneity, Interfaces and Complex Vitrification Behavior of Epoxy-based Materials by Broadband Dielectric Spectroscopy and Calorimetry
N2 - Although in the last decades epoxy-based nanocomposites have been successfully adopted by the marine, automotive and aerospace industries they are still rarely studied on a fundamental level. This work deals with an in-depth comparative investigation of the structure, molecular mobility and vitrification kinetics of three bisphenol A diglycidyl ether (DGEBA)-based materials with different nanofillers: I) taurine-modified layered double hydroxide (T-LDH), II) boehmite (BNPs) and III) halloysite nanotubes (HNTs). Moreover, the effect of different hardeners (diethylene triamine and methyl tetrahydrophtalic acid anhydride) on the unfilled epoxy matrix is addressed as well. The chosen methodology comprises I) small – and wide – angle X-ray scattering (SAXS/WAXS) II) calorimetry in the forms of a) conventional DSC and b) static fast scanning calorimetry (FSC), III) broadband dielectric spectroscopy (BDS), as well as IV) specific heat spectroscopy in the forms of a) temperature modulated DSC, and b) temperature modulated FSC. The combination of these techniques proved an intrinsic spatial heterogeneity of epoxy-based materials, evidenced by two separate segmental relaxation processes. Although, depending on the hardener the response of the systems to calorimetric and dielectric investigations was different, in a broader sense similar conclusions can be extracted on the structural heterogeneity. As expected from the two distinct α-processes, it was shown that, in parallel to the main glass transition, epoxy-based materials can exhibit an additional low temperature vitrification mechanism, which was not discussed in prior studies for an unfilled network former. Furthermore, the interfacial region (so-called rigid amorphous fraction) was qualitatively and quantitatively addressed, in dependence of the employed nanofiller structure.
T2 - Webinar University of Southern Denmark
CY - Online meeting
DA - 20.01.2021
KW - BDS
KW - Nanocomposites
KW - Epoxy
KW - Rigid amorphous fraction
KW - TMDSC
KW - Flash DSC
PY - 2021
AN - OPUS4-52036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schoenhals, Andreas
T1 - The bahvior of inonic liquid crystals as investigated by broadband dielectric spectroscopy and complementary methodas
N2 - The behavior of liquid crystals based on phenylbenzoate was investigated using broadband dielectric spectroscopy and advanced calorimetry. The length of the alkyl side chain was systematically varied from 8 to 16 carbon atoms. The experimental results were compared with those obtained from molecular dynamics simulations.
T2 - Sympoium: "Dipoles is soft matter - How they move and organize"
CY - Leuven, Belgium
DA - 06.06.2025
KW - Ionic liquid crystals
PY - 2025
AN - OPUS4-63316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation
N2 - We report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all Poly(tricyclononenes) with Si(OR)3 side groups, which is interpreted in terms of a percolation model.
T2 - Chemical Engg Seminar
CY - Columbia University, NY, USA
DA - 14.03.2023
KW - Glass transition
KW - Conductivity
KW - Fast Scanning Calorimetry
KW - Dynamics
PY - 2023
AN - OPUS4-57343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Dynamics and conductivity of nanoconfined amino acid based superdiscs: Influence of the side chain length
N2 - Ionic Liquid Crystals (ILCs) are emerging class of materials that combine the properties of liquid crystals with the ionic conduction similar to ionic liquids. It’s known that liquid crystals exhibit intriguing properties when confined and are of importance from both fundamental and technological perspective. Here, we study the molecular dynamics and electrical conductivity of a homologous series of Dopamine (DOPA) based ILCs, ILCn (n = 12,14,16) confined in self ordered nanoporous alumina oxide membrane of 180 nm pore size using Broadband Dielectric Spectroscopy (BDS). We aim to understand how the alkyl chain length and confinement influence the dynamics in this system.
In the bulk, for all ILCs, we observe two relaxation modes in the crystalline phase, the and α1 relaxation respectively, and one relaxation mode in the columnar phase, the α2 relaxation, but for ILC16, where two relaxation modes (α2 and α3) are detected in the columnar phase.
For the confined case, all relaxation processes slowdown compared to the bulk. For ILC16, the α1 relaxation is completely suppressed. For all ILCs, the absolute values of DC conductivity are reduced by some three orders of magnitude. We discuss in detail the possible molecular origin of the relaxation processes and the charge transport in this system.
T2 - CONFIT 2022
CY - Grenoble, France
DA - 10.10.2022
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2022
AN - OPUS4-57341
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Guiping
A1 - Liu, Ye
A1 - Schultz, Thorsten
A1 - Exner, Moritz
A1 - Muydinov, Ruslan
A1 - Wang, Hui
A1 - Scheurell, Kerstin
A1 - Huang, Jieyang
A1 - Szymoniak, Paulina
A1 - Pinna, Nicola
A1 - Koch, Norbert
A1 - Adelhelm, Philipp
A1 - Bojdys, Michael J.
T1 - One‐Pot Synthesis of High‐Capacity Sulfur Cathodes via In‐Situ Polymerization of a Porous Imine‐Based Polymer
N2 - AbstractLithium‐ion batteries, essential for electronics and electric vehicles, predominantly use cathodes made from critical materials like cobalt. Sulfur‐based cathodes, offering a high theoretical capacity of 1675 mAh g−1 and environmental advantages due to sulfur's abundance and lower toxicity, present a more sustainable alternative. However, state‐of‐the‐art sulfur‐based electrodes do not reach the theoretical capacities, mainly because conventional electrode production relies on mixing of components into weakly coordinated slurries. Consequently, sulfur‘s mobility leads to battery degradation—an effect known as the “sulfur‐shuttle”. This study introduces a solution by developing a microporous, covalently‐bonded, imine‐based polymer network grown in situ around sulfur particles on the current collector. The polymer network (i) enables selective transport of electrolyte and Li‐ions through pores of defined size, and (ii) acts as a robust host to retain the active component of the electrode (sulfur species). The resulting cathode has superior rate performance from 0.1 C (1360 mAh g−1) to 3 C (807 mAh g−1). Demonstrating a high‐performance, sustainable sulfur cathode produced via a simple one‐pot process, our research underlines the potential of microporous polymers in addressing sulfur diffusion issues, paving the way for sulfur electrodes as viable alternatives to traditional metal‐based cathodes.
KW - In-situ polymerization
KW - Sulfur cathodes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604215
DO - https://doi.org/10.1002/anie.202400382
SN - 1433-7851
SP - 1
EP - 11
PB - Wiley VHC-Verlag
AN - OPUS4-60421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elert, Anna Maria
A1 - Chen, Yong-Cin
A1 - Smales, Glen Jacob
A1 - Topolniak, Ievgeniia
A1 - Sturm, Heinz
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Effects of the charge density of nanopapers based on carboxymethylated cellulose nanofibrils investigated by complementary techniques
N2 - Cellulose nanofibrils (CNFs) with different charge densities were prepared and investigated by a combination of different complementary techniques sensitive to the structure and molecular dynamics of the system. The morphology of the materials was investigated by scanning electron microscopy (SEM) and X-ray scattering (SAXS/WAXS). The latter measurements were quantitatively analyzed yielding to molecular parameters in dependence of the charge density like the diameter of the fibrils, the distance between the fibrils, and the dimension of bundles of nanofibrils, including pores. The influence of water on the properties and the charge density is studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and broadband dielectric spectroscopy. The TGA measurements reveal two mass loss processes. The one at lower temperatures was related to the loss of water, and the second process at higher temperatures was related to the chemical decomposition. The resulting char yield could be correlated to the distance between the microfibrils. The DSC investigation for hydrated CNFs revealed three glass transitions due to the cellulose segments surrounded by water molecules in different states. In the second heating scan, only one broad glass transition is observed. The dielectric spectra reveal two relaxation processes. At low temperatures or higher frequencies, the β-relaxation is observed, which is assigned to localized fluctuation of the glycosidic linkage. At higher temperatures and lower frequencies, the α-relaxation takes places. This relaxation is due to cooperative fluctuations in the cellulose segments. Both processes were quantitatively analyzed. The obtained parameters such as the relaxation rates were related to both the morphological data, the charge density, and the content of water for the first time.
KW - Cellulose nanofibrils
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600528
DO - https://doi.org/https://doi.org/10.1021/acsomega.4c00255
SN - 2470-1343
VL - 9
SP - 20152
EP - 20166
PB - ACS
AN - OPUS4-60052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
A1 - Hertwig, Andreas
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Signature of the Adsorbed Layer on the glass transition of thin polymer Films: Broadband Dielectric spectroscopy and related techniques
N2 - In well annealed thin polymer films with non-repulsive polymer/substrate interaction with a substrate an irreversibly adsorbed layer is expected to form. These adsorbed layers have shown a great potential for technological applications [1]. However, the growth kinetics and the molecular mobility of the adsorbed layer is still not fully understood. This concerns also the influence of the adsorbed layer on the thickness dependence of the glass transition temperature of thin films. This is partly due to the difficult accessibility of these layers in thin films. Here, the irreversibly adsorbed layers of semi-rigid mail chain polymers like polycarbonate or polysulfone are revealed by solvent-leaching experiments. First, the growth kinetics of these layers is investigated as a function of annealing time. The film thickness, topography and the quality of the adsorbed layer is controlled by Atomic Force Microscopy (AFM). Secondly, the molecular mobility of the adsorbed layer is investigated by Broadband Dielectric Spectroscopy (BDS). A developed nanostructured capacitor arrangement is employed to measure the layer with a free surface. In addition to the dielectric experiments, spectroscopic Ellipsometry measurements are carried out to estimate the glass transition of the thin films. The thickness dependence of the glass transition of the thin films is correlated with the adsorbed layer [2,3].
Acknowledgments
D. Hülagü and G. Hidde thanked for the help with the ellipsometry measurements.
T2 - 12. Conference on Broabband Dielectric Spectroscopy and its Application
CY - Lisbon, Portugal
DA - 01.09.2024
KW - Thin films
PY - 2024
AN - OPUS4-60959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Smales, Glen Jacob
A1 - Henning, S.
A1 - Li, Z.
A1 - Wang, D.-Y.
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Calorimetric and Dielectric Investigations of Epoxy-Based Nanocomposites with Halloysite Nanotubes as Nanofillers
N2 - Epoxy nanocomposites are promising materials for industrial applications (i.e., aerospace, marine and automotive industry) due to their extraordinary mechanical and thermal properties. Here, the effect of hollow halloysite nanotubes (HNT) on an epoxy matrix (Ep) was the focus of the study. The structure and molecular mobility of the nanocomposites were investigated using a combination of X-ray scattering, calorimetry (differential (DSC) and fast scanning calorimetry (FSC)) and dielectric spectroscopy. Additionally, the effect of surface modification of HNT (polydopamine (PDA) and Fe(OH)3 nanodots) was considered. For Ep/HNT, the glass transition temperature (Tg) is was de-creased due to a nanoparticle-related decrease of the crosslinking density. For the modified system, Ep/m-HNT, the surface modification resulted in enhanced filler–matrix interactions leading to higher Tg values than the pure epoxy in some cases. For Ep/m-HNT, the amount of interface formed between the nanoparticles and the matrix ranged from 5% to 15%. Through BDS measurements, localized fluctuations were detected as a β- and γ-relaxation, related to rotational fluctuations of phenyl rings and local reorientations of unreacted components. A combination of calorimetry and BDS dielectric spectroscopy revealed a dynamic and structural heterogeneity of the matrix, as confirmed by two glassy dynamics in both systems, related to regions with different crosslinking densities.
KW - Rigid amorphous fraction
KW - Epoxy nanocomposites
KW - Halloysite nanotubes
KW - X-ray scattering
KW - Differential scanning calorimetry
KW - Broadband dielectric spectroscopy
KW - Flash DSC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526668
DO - https://doi.org/10.3390/polym13101634
VL - 13
IS - 10
SP - 1634
PB - MDPI
AN - OPUS4-52666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radnik, Jörg
T1 - (hard) x ray photoelectron spectroscopy as tool in nano-analytics
N2 - Selected samples are used to show, that photoelectron spectroscopy is an important tool for measuring nano-objects, especially for determing the chemical composition and structure on the nanosacle. XPS with different energies offers new possibilities in depth-profiling.
T2 - SFB 1073 Colloquium
CY - Göttingen, Germany
DA - 22.02.2024
KW - X-ray photoelectron spectroscopy
KW - Core-shell nanoparticle
KW - Graphene related 2D materials
PY - 2024
AN - OPUS4-59589
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy, advanced calorimetry and Neutron Scattering
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n=5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations a γ-relaxation due to localized fluctuations as well as two glassy dynamics the αcore and αalkyl relaxation were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n=8 from a rigid constrained (n=5,6) to a softer system (n=10,12) on a molecular lenght scale was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition. The results were confirmed by in- and quasielastic neutron scattering
T2 - Confit 2022
CY - Grenoble, France
DA - 10.10.2022
KW - Glassy Dynamics
KW - Discotic Liquid Crystals
PY - 2022
AN - OPUS4-56661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Szymoniak, Paulina
T1 - Dataset and Jupyter worksheet interpreting the (results from) small- and wide-angle scattering data from a series of boehmite/epoxy nanocomposites. Accompanies the publication "Competition of nanoparticle-induced mobilization and immobilization effects on segmental dynamics of an epoxy-based nanocomposite"
N2 - Dataset and Jupyter worksheet interpreting the (results from) small- and wide-angle scattering data from a series of boehmite/epoxy nanocomposites. Accompanies the publication "Competition of nanoparticle-induced mobilization and immobilization effects on segmental dynamics of an epoxy-based nanocomposite", by Paulina Szymoniak, Brian R. Pauw, Xintong Qu, and Andreas Schönhals.
Datasets are in three-column ascii (processed and azimuthally averaged data) from a Xenocs NanoInXider SW instrument. Monte-Carlo analyses were performed using McSAS 1.3.1, other analyses are in the Python 3.7 worksheet. Graphics and result tables are output by the worksheet.
KW - Small angle scattering
KW - X-ray scattering
KW - Nanocomposite
KW - Polymer nanocomposite
KW - Boehmite
KW - Analysis
KW - SAXS/WAXS
PY - 2020
DO - https://doi.org/10.5281/zenodo.4321087
PB - Zenodo
CY - Geneva
AN - OPUS4-51829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed Aejaz
A1 - Smales, Glen Jacob
A1 - ZhuoQing, Li
A1 - Yildirim, Arda
A1 - Wuckert, E.
A1 - Eutionnat, S.
A1 - Demel, F.
A1 - Huber, P
A1 - Lasachat, S.
A1 - Schönhals, Andreas
T1 - Side Chain Length-Dependent Dynamics and Conductivity in Self-Assembled Ion
N2 - We study the molecular mobility and electrical conductivity of a homologous series of linear shaped columnar ionic liquid crystals ILCn, (n = 8, 10, 12, 14, 16) using broadband dielectric spectroscopy (BDS), specific heat spectroscopy (SHS), and X-ray scattering. We aim to understand how the alkyl chain length influences the dynamics and electric conductivity in this system. Two dielectrically active relaxation modes are observed, the γ and the αcore process, that correspond to the localized fluctuations of the alkyl chains and cooperative motions of the aromatic core in the columns, respectively. Both the γ relaxation and the αcore process slow down with increasing alkyl chain length. SHS reveals one relaxation process, the αalkyl process that has a similar temperature dependence as that of the αcore process for ILC12, 14, and 16 but shifts to higher temperature for ILC8 and 10. For ILC12, 14, and 16, the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. For ILC8 and 10, the DC conductivity behavior is similar to ionic liquids, where the conductivity is coupled with structural relaxation. Small-angle X-ray investigations reveal that both the intercolumnar distance and the disorder coherence length increase with alkyl chain length; conversely, the DC conductivity decreases monotonically.
KW - Ionic Liquid Crystals
PY - 2022
DO - https://doi.org/10.1021/acs.jpcc.2c03023
SN - 1932-7447
VL - 126
IS - 27
SP - 10995
EP - 11006
PB - ACS
AN - OPUS4-55194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zosef, M.
A1 - Fahmy, Alaa
A1 - El Hotaby, W.
A1 - Hassan, A.
A1 - Khalil, A.
A1 - Anis, B.
T1 - High performance graphene-based PVF foam for lead removal from water
N2 - The synthesis and optimization of superior and eco-friendly sorbents for Pb(II) pose a great challenge in the field of water treatment. The sorbent was developed by introducing graphene oxide (GO) into the matrix of polyvinyl formaldehyde (PVF) foam. The immobilization of GO in PVF results in significant increase in the maximum adsorption capacity (Qt) of GO powder for Pb(II), from ≈800 to ≈1730 mg g−1 in the case of GO/PVF foam. As compared with GO powder in Pb(II) aqueous solutions, PVF matrix keeps GO sheets stable without any agglomeration. The large surface area of GO sheet allows the abundant oxygenated functional groups on its surface to participate effectively in the Pb(II) adsorption process, leading to the huge increase of the Qt. Adsorption isotherms and kinetic studies indicated that the sorption process of Pb(II) on GO/PVF was done on heterogenous surface by ion-exchange reaction. The GO/PVF foam showed an excellent reusability for more than 10 cycles with almost the same efficiency and without any significant change in its physical properties.
KW - Water treatment
KW - Graphene oxide
KW - Lead ions
KW - Polyvinyl formaldehyde foam
KW - Superior sorbent
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523013
DO - https://doi.org/10.1016/j.jmrt.2020.08.011
VL - 9
IS - 5
SP - 11861
EP - 11875
PB - Elsevier B.V.
AN - OPUS4-52301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Abou-Saied, M.
A1 - Helaly, H.
A1 - El-Dessoki, F.
A1 - Mohamed, T.
T1 - Novel PVA/Methoxytrimethylsilane elastic composite membranes: preparation, characterization and DFT computation
N2 - A modified composite membranes (PVA/SiOH/SiOC) were made via solution-casting process using different 1:1, 1:2, 1:3 and 1:4 volume ratios of polyvinyl alcohol (PVA):methoxytrimethylsilane (MTMS). Moreover, FT-infrared and energy-dispersive X-ray spectroscopy (EDX) were mesured to account for the network structural rearrangements involving silicon within PVA matrices. The addition of MTMS has improved the thermal and mechanical properties of the composite membranes as compared to pristine PVA. In addition, the crystallinity and the morphological changes of PVA/MTMS composites was studied using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. Three structures were suggested based on trimethyl silanol (I) wet out condensation (II and III) with the dopped PVA followed by and H-bonding interactions (IV). The outcomes of B3LYP/6-31G(d) frequency calculations favors a three-dimensional SiOC linked network (III). Nevertheless, EDX reveals, the 3D SiOC links are not observed on the surface of composite membranes, however, is found dominant in the bulk, [(CH3)3SiOCH2CH2CH2O]n. Moreover, the solubility, density, and refractive index of the synthesized composites were measured and found depended on the ratio of PVA in the composite membranes. The current results are compared with that published earlier including dimethoxydimethylsilane at the same conditions.
KW - Polymer composites
KW - DFT calculations
KW - Elastic membrane
KW - Methoxytrimethlsilane
KW - Polyvinyl alcohol
PY - 2021
DO - https://doi.org/10.1016/j.molstruc.2021.130173
VL - 1235
SP - 130173
PB - Elsevier B.V.
AN - OPUS4-52302
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohamed, W. A. A.
A1 - Fahmy, Alaa
A1 - Helal, A.
A1 - Ahmed, E. A. E.
A1 - Elsayed, B. A.
A1 - Kamoun, E. A.
A1 - Gad, E. A. M.
T1 - Degradation of local Brilliant Blue R dye in presence of polyvinylidene fluoride/MWCNs/TiO2 as photocatalysts and plasma discharge
N2 - The need of clean water and the water-poor are increasing daily in the world. In addition, we are facing a dramatic increase in the industrial pollutions of rivers and groundwater, which led us to find a new way to treat industrial pollutants. The plasma discharge technique is one of the important, safe, and applicable for industrial wastewater decontamination. Decolorization of Brilliant Blue R (BBR) dye as a hazard material was noticed when the contaminated solution was exposed to the plasma discharge technique. The combination between the nonthermal plasma and catalysts was evaluated in this work to optimize the degradation efficiency. The PVDF/(MWCNTs/TiO2) as three system composites was employed to enhance the nonthermal plasma performance. The surface area, phase purity, shape, and photonic efficiency were characterized employing XRD, FTIR, SEM, DSC, and UV–Vis. techniques. The obtained results of degradation using NTP technique in presence of the PVDF/MWCNTs catalyst have been enhanced the BBR dye degradation by 19% than only plasma treatment for 20 min.
The durability processes of prepared PVDF/(MWCNTs/TiO2) was investigated and evaluated until 8 solar photocatalytic process repeating times.
KW - Brilliant Blue R
KW - MWCNT
KW - PVDF
PY - 2022
DO - https://doi.org/10.1016/j.jece.2021.106854
VL - 10
IS - 1
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-54386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Saied, M. A. A.
A1 - Morgan, N.
A1 - Abdelbary, H.
A1 - Bahy, S. M.
A1 - Schönhals, Andreas
A1 - Friedrich, J. F.
T1 - Modified polyvinyl chloride membrane grafted with an ultra-thin polystyrene film: structure and electrochemical properties
N2 - The work explores the synthesis and the properties of a novel composite membrane System based on modified polystyrene (PS) grafted onto a polyvinyl chloride (PVC) membrane.
PVC membranes were prepared by solution-casting followed by exposure to an atmospheric pressure dielectric barrier discharge (DBD) with O2 to obtain an activated Surface for grafting PS to it. Moreover, the thus prepared membranes were chemically modified furthermore by amination with polyethyleneimine or sulfonation with 4 M sulfuric acid.
The membrane surface characteristics such as wettability, structure and morphology were investigated using water contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy experiments. The thermogravimetric stability and electrolytic responses of the membranes were studied utilizing TGA, ion exchange capacity (IEC), and solvent uptake. A significant result of plasma and chemical modification was to produce a membrane material with low permeability. Thus, the methanol permeability of the sulfonated membranes measured for 12 h was measured to 2.34$10� 8 cm2 s� 1 compared to 177.00$10� 8 cm2 s� 1 of Nafion 117®which is considered as a benchmark. This result indicates that the prepared sulfonated samples are an innovative and effective material for decreasing the methanol crossover in fuel cells to a great extent. This makes the PVC-g-St membranes are promising and attractive as new materials for polyelectrolyte membrane for fuel cells.
KW - Electrolyte membrane
KW - Fuell cells
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526794
DO - https://doi.org/10.1016/j.jmrt.2021.04.018
VL - 12
SP - 2273
EP - 2284
PB - Elsevier B.V.
AN - OPUS4-52679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mechichi, R.
A1 - Chabbah, T.
A1 - Chatti, S.
A1 - Jlalia, I.
A1 - Sanglar, Corinne
A1 - Casablanca, H.
A1 - Vulliet, E.
A1 - Marestin, C.
A1 - Mercier, R.
A1 - Weidner, Steffen
A1 - Errachid, A.
A1 - Hammani, M.
A1 - Jaffrezic-Renault, N.
A1 - Abderrazak, H.
T1 - Semi‑interpenetrating Network‑Coated Silica Gel Based on Green Resources for the Efcient Adsorption of Aromatic Pollutants from Waters
N2 - In the framework of the development of green analytical chemistry, a silica gel (SG) coated with a semi-penetrating network based on the partially biosourced poly(ethersulfone) is studied for a greener extraction process of aromatic organic pollutants. An optimized composition of the semi-penetrating network (80% of the linear polymer (LP): isosorbide-based poly(ethersulfone) and 20% cross-linking agent (XP) type bismaleimide) leads to a total adsorption of the selected aromatic pollutants, whatever their hydrophilicity. Adsorption characteristic, kinetics and isotherms of the SG-semi-INP LP80/XP20 for p-hydroxybenzoic acid and for toluic acid were studied. Langmuir model led to a better ftting of the adsorption isotherms; the adsorption of toluic acid is easier than that of p-hydroxybenzoic acid. 1/n values of benzoic acid was lower for SGsemi-INP LP80/XP20 compared to biochar and to cross-linked methacrylate resin, showing a higher adsorption efciency.
KW - Isosorbide
KW - Semi-interpenetrating networks
KW - Silica gel modification
KW - Aromatic pollutants
KW - Adsorption
PY - 2022
DO - https://doi.org/10.1007/s42250-022-00463
SN - 2522-5758
SP - 1
EP - 18
PB - Springer
AN - OPUS4-55720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Upcycling waste PET bottles to porous UiO-66 by mechanochemistry
N2 - Single-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or gets incinerated in a highly unsustainable manner. Here, I will present a sustainable mechanochemical protocol for the chemical upcycling of polyethylene terephthalate (PET) to porous UiO-66 metal-organic framework (MOF). In the first step, PET is ball-milled with sodium hydroxide and undergoes alkaline hydrolysis to disodium terephthalate (Na2TP). Time-resolved in situ monitoring of ball milling reaction by synchrotron powder X-ray diffraction shows the appearance of crystalline Na2TP after 20 min of milling. However, ex-situ analysis at different milling times by gel permeation chromatography reveals that the depolymerisation step needs more milling for completion. After two hours of ball milling, there are only trace amounts of leftover PET. For upcycling to UiO-66, a zirconium acetate cluster is added to Na2TP together with liquid additives and after milling for
T2 - International Conference on Resource Chemistry 2024
CY - Alzenau, Germany
DA - 13.03.2024
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2024
AN - OPUS4-62105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brirmi, N.
T1 - Effect of the pendant groups on the biobased polymers obtained by click chemistry suitable for the removal of phenolic compounds from water
N2 - Phenolic compounds constitute a widespread and important class of water pollutants that should be efficiently removed from wastewater because of their toxicity even at low concentrations. They are indeed discharged in the liquid effluents from various factories: chemical, petrochemical, paper, wood, metallurgy and cocking plants 1. Phenols are also found in the waste waters of agroindustrial processes like the olive oil mills, tomato processing and wine distilleries 2,3. These contaminants cause several health problems for humans and aquatic organisms 4. Therefore, numerous studies on the removal of polyphenols from wastewaters have been conducted and many techniques have been used. Among them, adsorption is considered to be the best effective and low cost method. In this context, we have focused our efforts on optimizing adsorption process by development of novel, low-cost adsorbents derived from biobased byproducts with high adsorptive capacity.
The main aim of this study is to synthesize triazole-based poly(ether-pyridine)s as new synthetic adsorbent phases for the extraction of phenolic compounds from aqueous solutions. For this purpose, new fluoromonomers containing 1,2,3-triazole units were prepared by the Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction and then used for the elaboration of novel poly(ether-pyridine-triazole)s (PEPTs) by direct polycondensation with isosorbide and bisphenol A. Chemical structure of fluorinated pyridinic monomers as well as resulting polymers was confirmed by 1H and 19F NMR spectroscopic methods. The thermal behaviour of the obtained PEPTs was characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Their uptake performance to eliminate organic compounds was determined using High Performance Liquid Chromatography (HPLC).
T2 - 12. Journees maghreb-europe. Matériaux et Applications aux Dispositifs et Capteurs
CY - Monastir, Tunisia
DA - 08.11.2022
KW - Biobased polymers
KW - Phenolic compounds
KW - 1,2,3-triazole
PY - 2022
AN - OPUS4-56287
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Eggert, Lara
A1 - Burkert, Andreas
T1 - H2Mare-Projekt PtX-Wind - Untersuchung zu bauseitigen Fragestellungen der Korrosion und des Korrosionsschutzes mit Fokus auf die Außenkorrosion von Bau- und Anlagenteilen
N2 - Im Teilvorhaben „Untersuchung zu bauseitigen Fragestellungen der Korrosion und des Korrosionsschutzes mit Fokus auf die Außenkorrosion von Bau- und Anlagenteilen“ standen korrosionstechnische Untersuchungen zum Einfluss maritimer Exposition für großtechnische Offshore-Power-to-X-(PtX-) Anlagen im Mittelpunkt. Die Planung und der Betrieb solcher OffshoreProzessanlagen stellen aufgrund der vorherrschenden Umweltbedingungen hohe Anforderungen an die Korrosionsbeständigkeit der eingesetzten Materialien, wobei dem wirksamen Korrosionsschutz eine zentrale Rolle für einen wartungsarmen, langlebigen und umweltverträglichen Anlagenbetrieb zukommt.
Vor diesem Hintergrund wurde das Korrosionsverhalten metallischer Werkstoffe und Korrosionsschutzsysteme unter realen maritimen und Offshore-Bedingungen systematisch untersucht. Durch die Verknüpfung normativer und wissenschaftlicher Literaturrecherchen mit kontrollierten Laboruntersuchungen sowie mehrjährigen Expositionsversuchen an ausgewählten maritimen Standorten wurden grundlegende Zusammenhänge zwischen Umweltparametern, Werkstoffeigenschaften, konstruktiven Randbedingungen und Korrosionsmechanismen analysiert. Die gewonnenen Ergebnisse stellen eine repräsentative Datengrundlage zur Charakterisierung der Korrosivitätsbedingungen im maritimen Umfeld dar und bilden eine wissenschaftlich fundierte Basis für die Bewertung, Auslegung und Optimierung von Werkstoffen, Beschichtungen und Korrosionsschutzkonzepten für maritime und Offshore-Anwendungen.
KW - Offshore-Power-to-X-Anlagen
KW - Maritime Korrosion
KW - Korrosionsschutz
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657965
DO - https://doi.org/10.34657/32992
SP - 1
EP - 32
AN - OPUS4-65796
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Burkert, Andreas
A1 - Eggert, Lara
T1 - H2Mare-Projekt TransferWind - Übertragung von wissenschaftlichen Erkenntnissen zur bauseitigen maritimen und offshore-Korrosion in die Normung und Erarbeitung einer Handlungsempfehlung zu Korrosionsschutz und -prüfung
N2 - Die Werkstoffauswahl und der Korrosionsschutz zur Sicherstellung der Dauerhaftigkeit stellen für den Offshore Bereich noch immer eine Herausforderung dar. Erfahrungen und Regelwerke liegen insbesondere aus dem Bereich von Offshore Windenergieanlagen vor. Diese Regelwerke befinden sich in einem stetigen Prozess der Anpassung an aktuelle Erkenntnisse und Erfahrungen, da es sich noch um relativ neue Anwendungen handelt. Für Offshore-Prozessanlagen, wie diese im H2Mare-Projekt betrachtet werden, sind die Anforderungen wesentlich komplexer, da Anlagenkomponenten den Beanspruchungen aus den Prozessen im Inneren der Anlagen ebenso genügen müssen, wie den Beanspruchungen aus der maritimen Umgebung. Hier kommen im Vergleich zu Windkraftanlagen eine größere Palette von Werkstoffen insbesondere aus dem Bereich der rost- und säurebeständigen Stähle sowie höhere Prozesstemperaturen zum Tragen, die für Windkraftanlagen keine Relevanz haben.
KW - Offshore-Power-to-X-Anlagen
KW - Maritime Korrosion
KW - Korrosionsschutz
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658008
DO - https://doi.org/10.34657/32991
SP - 1
EP - 25
AN - OPUS4-65800
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Witt, Julia
T1 - Electrocatalyticperformance and stabilityofmulti-principalelement alloys (MPEAs)
N2 - Accurately distinguishing oxygen evolution reaction (OER) currents from anodic metal dissolution is essential for accurately evaluating metal electrocatalysts, as both processes often overlap in the transpassive potential region.1,2 This study explored multi-principal element alloys (MPEAs) as a pathway toward sustainable electrocatalysis by reducing reliance on noble and critical metals. CrCoNi and CrMnFeCoNi alloys are used as model systems to understand how complex compositions behave when OER and dissolution occur simultaneously, providing a benchmark for designing Co-reduced/free variants within the FeCrNi MPEA family.
To quantitatively separate these pathways, we employ an integrated operando approach: tip-substrate voltammetry in scanning electrochemical microscopy (TSV-SECM) for spatially resolved O2 detection, ICP-MS and UV-Vis spectroscopy for dissolution quantification and chromium speciation, and in-situ electrochemical AFM (EC-AFM) to identify the onset of corrosion and track nanoscale surface evolution. Converting dissolution data into electrochemical charge enables a precise attribution of transpassive currents to either OER or metal dissolution. To further assessmass-transport effects, MPEAs were examined using rotating disk electrode (RDE) methods. Controlled hydrodynamics separate kinetic from diffusion-limited regimes and reveal how dissolution rates, passive-film behavior, and OER activity respond under flow conditions.
Overall, this methodology provides a robust platform for reliably distinguishing catalytic OER performance from corrosion processes while guiding the design of next-generation electrocatalysts that minimize or eliminate Co and other critical and noble metals. Extending these insights to FeCrNi-based systems offers new opportunities for sustainable, high-performance materials capable of operating under technologically relevant anodic conditions.
T2 - Materials for Sustainable Development Conference (MATSUS26)
CY - Barcelona, Spain
DA - 23.03.2026
KW - Multi-principal elemt alloy (MPEAs), Corrosion, Electrocatalysis, Scanning electrochemical miscroscopy (SECM)
PY - 2026
AN - OPUS4-65791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Miyata, Ayana
A1 - Tokuda, Shun
A1 - Kuzumoto, Mako
A1 - Lee, Guan-Sian
A1 - Yamashita, Masataka
A1 - Nishiguchi, Taichi
A1 - Negoro, Masaki
A1 - Pauw, Brian Richard
A1 - Chan, Yi-Tsu
A1 - Kanamori, Kazuyoshi
A1 - Urayama, Kenji
A1 - Sugimoto, Kunihisa
A1 - Furukawa, Shuhei
T1 - One-Dimensional van der Waals Porous Fibrils Assembled from Metal–Organic Polyhedra
N2 - Supramolecular systems exhibit collective functions that emerge from the hierarchical assembly of individual molecular building blocks. Metal−organic polyhedra (MOPs) are a class of functional supramolecular architectures with well-defined molecular geometry and an intrinsic cavity. In recent years, considerable progress has been made in assembling MOPs into extended networks to create porous solids. However, most reported MOP assemblies are limited to three-dimensional networks, which, owing to their high-dimensional connectivity, hinder effective stress dissipation and render them brittle under mechanical stress.
Here, we report the one-dimensional (1D) self-assembly of MOPs into supramolecular polymeric aerogels that combine permanent microporosity with exceptional mechanical flexibility. The reaction between amino acid-functionalized naphthalenediimide (NDI) linkers and copper salts led to the synthesis of octahedral copper-based MOPs, followed by their spontaneous self-assembly to form supramolecular gels. The corresponding aerogels converted from the gels possessed uniform 1D fibrillar networks (14.8 ± 2.2 nm in width) with intrinsic microporosity derived from individual MOP cavities. The aerogel endured 87% compressive strain without fracture, demonstrating distinct ductility. Furthermore, these fibrils in the supramolecular gels were converted to crystals after 2 weeks. Single-crystal X-ray diffraction revealed that MOPs are arranged via face-to-face interaction between octahedral MOPs to form a 1D helical chain structure. An analysis of the self-assembly process using Hansen solubility parameters unveiled that solvent conditions with high polarity and low dispersion interaction drive the formation of anisotropic assemblies. This work provides a new strategy for tailoring the mechanical properties of supramolecular materials through dimensional control of their assemblies.
KW - Aerogels
KW - Crystals
KW - Metal organic frameworks
KW - Nanofibers
KW - Solvents
KW - X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Small-angle X-ray scattering
PY - 2026
DO - https://doi.org/10.1021/jacs.5c21654
SN - 0002-7863
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-65776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Pekin, Thomas C.
A1 - Luo, Xin-Yu
A1 - Sun, Yonghao
A1 - Koch, Christoph T.
A1 - Derlet, Peter M.
A1 - Maaß, Robert
T1 - Spatial distribution and connectivity of medium-range order signatures in a metallic glass probed with simulated and experimental 4DSTEM
N2 - challenge. Here, we assess the statistical signature of local diffraction symmetries and their spatial distribution obtained with transmission electron microscopy in both experimentally cast Pd-based MGs and simulated binary model glasses. A detailed analysis of diffraction symmetries from the model glass shows that microstructural coarsening is dominated by icosahedra and Frank–Kasper polyhedra. While symmetries for these motifs are less significant for the laboratory-cast Pd-based glass, clear signatures of symmetry-cluster coarsening as a function of relaxation state are observed in both experiments and simulations, without any indications for crystallization. These findings give support for a qualitatively similar evolution of a glassy microstructure at the medium-range order length scale during glass relaxation.
KW - Metallic glass
KW - TEM
KW - Molecular dynamics simulations
KW - Glass structure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657772
DO - https://doi.org/10.1016/j.jallcom.2026.186631
SN - 0925-8388
VL - 1058
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ruehle, Bastian
T1 - The Role of Analytics for Closing the Loop in Self-Driving Labs
N2 - The recent emergence of self-driving laboratories (SDL) and material acceleration plat-forms (MAPs) demonstrates the ability of these systems to change the way chemistry and material syntheses will be performed in the future. Especially in conjunction with nano- and advanced materials which are generally recognized for their great potential in solving current material science challenges, such systems can make disrupting con-tributions. Consequently, new tools that enhance the development and optimization cycle of nano- and advanced materials are crucial. In this contribution, we present our Self-Driving Lab (SDL) for Nano and Advanced Materials [1], that integrates robotics for batched autonomous synthesis – from molecular precursors to fully purified nano-materials – with automated characterization and data analysis, for a complete and reli-able nanomaterial synthesis workflow. By automating the processing and characteriza-tion steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility, reproducibility, and flexibility of the platform.
The system also incorporates in-line characterization measurement of hydrodynamic diameter, zeta potential, and optical properties (absorbance, fluorescence). In general, the interface with data analysis algorithms from in-line, at-line, and off-line measure-ments is of great importance for closing the design-make-test-analyze cycle and using these platforms efficiently. Here, we will give examples of how automatic image seg-mentation of electron microscopy images with the help of AI [2] can be used for reduc-ing the “data analysis bottleneck” from an off-line measurement. We will also discuss various machine learning (ML) algorithms that are currently implemented in the backend and can be used for ML-guided, closed-loop material optimization in our SDL. Lastly, we will show our recent efforts [3] in making the workflow generation on SDLs more user-friendly by using large language models to generate executable workflows automatically from synthesis procedures given in natural language and user-friendly graphical user interfaces based on node editors that also allow for knowledge graph extraction from the workflows. In this context, we are currently also working on a com-mon description or ontology for representing the process steps and parameters of the workflows, which will greatly facilitate the semantic description and interoperability of workflows between different SDL hardware and software platforms.
These features underscore the SDL’s potential as a transformative tool for advancing and accelerating the development of nano- and advanced materials, offering solutions for a sustainable and environmentally responsible future.
T2 - Analytica Conference 2026
CY - Munich, Germany
DA - 24.03.2026
KW - Self-Driving Labs
KW - Materials Acceleration Platforms
KW - Advanced Materials
KW - Nanomaterials
KW - Automation
KW - Digitalization
KW - Ontologies
PY - 2026
AN - OPUS4-65760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bayat, Mehmet Emin
A1 - Nandayapa, Edgar R.
A1 - Tiebe, Carlo
A1 - Unger, Eva L.
A1 - List-Kratochvil, Emil J. W.
T1 - Raw data from: "An operando spectroscopic examination of the influence of trace humidity on interdigital back contact metal halide perovskite solar cells"
N2 - Controlling trace humidity is vital for both the fabrication and long-term stability of metal halide perovskite (MHP) solar cells. Relevant humidity levels are typically below 10 ppmV, especially in glovebox-based processing and in well-encapsulated devices. Even minute amounts during fabrication can influence crystallization, introducing defects and lowering efficiency. Over time, humidity accelerates degradation of the perovskite layer and internal interfaces, ultimately reducing operational lifetime. Probing these effects at low concentrations under operando conditions is therefore essential for advancing device performance and durability. In this work, we employed a high-precision transfer standard dew point hygrometer to investigate humidity levels between 5 and 35 ppmV in non-encapsulated MHP solar cells. To permit unobstructed water migration during operation, we fabricated interdigital back contact devices. Operando measurements revealed water transport through the perovskite layer and enabled quantification of outgassing. Under trace-humidified conditions, devices exhibited initial charge-carrier quenching, followed by gradual recovery. Notably, the photocurrent response to humidified nitrogen demonstrated that the MHP layer behaves fully reversibly within the explored timescale and across the investigated humidity levels and conditions. These findings establish a systematic operando framework for examining extrinsic stressors in perovskites and highlight opportunities for assessing passivation strategies.
KW - Metal halide perovskite
PY - 2026
DO - https://doi.org/10.5281/zenodo.18600851
PB - Zenodo
CY - Geneva
AN - OPUS4-65757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hübner, Martin
T1 - (K)ein explosives Thema? - Schweißen an und auf zukünftigen Wasserstoffpipelines im Betrieb unter Druckgasfluss
N2 - Das Schweißen an druckführenden Leitungen im Betrieb ist beim Erdgas-Fernleitungsnetz Stand der Technik, beispielsweise beim Setzen von Abgängen durch „Hot-Tapping“. Diese Technik wird auch beim zukünftigen Wasserstoff-Kernnetz eine bedeutende Rolle spielen. Verfahrensbedingt ist daher eine bestimmte Wasserstoffaufnahme während des Schweißens unvermeidbar. Aus diesem Grund werden derzeit in mehreren Forschungsprojekten wie umfassende Erkenntnisse zum Schweißen an Rohrleitungen unter Druckwasserstoff gewonnen. Die grundsätzliche Übertragbarkeit des „Hot-Tapping“ auf zukünftige Wasserstoff-Rohrleitungen wurde bereits bestätigt (u. a. DNV-Projekt und HyTap). Allerdings besteht allein das zukünftige Wasserstoff-Kernnetz in Deutschland aus einer Vielzahl von Bestands- und Neuwerkstoffen mit unterschiedlichen Festigkeiten, Durchmessern und Wandstärken. Für diese ist eine umfassende Betrachtung notwendig. In diesem Bereich leistet das Projekt H2-SuD wesentliche Beiträge, insbesondere zur Frage der Anpassung der Mindestwandstärke für sicheres Schweißen. Hierzu bieten die Demonstratoren eine ideale Grundlage zum Screening vieler Schweißparameter-Werkstoff-Kombinationen. Eine erhöhte Wasserstoffkonzentration beim Schweißen wurde experimentell belegt (DNV-Projekt und H2-SuD), allerdings im allgemein nicht als kritisch erachteten Bereich. Zudem wurde eine Wasserstoffversprödung der Schweißnaht während des Schweißens an druckwasserstoffführenden Demonstratoren bisher nicht beobachtet. Dies liegt u.a. an den mechanischen Eigenschaften der Rohrleitungswerkstoffe (gute Dehnfähigkeit, auch im geschweißten Zustand).
T2 - Vortragsreihe des Bezirksverbandes Berlin des Deutschen Verbandes für Schweißen und verwandte Verfahren (DVS) e.V.
CY - Berlin, Germany
DA - 25.03.2026
KW - Wasserstoff
KW - Rohrleitung
KW - Schweißen
KW - Demonstrator
KW - Bauteilprüfung
PY - 2026
AN - OPUS4-65774
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meier, F.
A1 - Drexel, R.
A1 - Wiesner, Yosri
A1 - Altmann, Korinna
A1 - Bartczak, D.
A1 - Alasonati, E.
T1 - Nano-sized Polypropylene as a Promising Candidate Reference Material: Preparation, Characterization and Stability in Complex Matrices
N2 - The lack of nanoplastic (NPs) reference materials capable of mimicking real-world scenarios is currently hampering the development of validated extraction techniques from complex matrices, the development of analytical approaches for robust identification and quantification, and the ability to use environmentally relevant test materials in (eco)toxicity testing and hazard assessment.
Here, we present a strategy towards the development of a potential NP reference material based on nano-sized polyproplyene particles (nanoPP) developed within the EURAMET-funded PlasticTrace project (https://plastictrace.eu/). The strategy includes the preparation, the physicochemical characterization and the stability assessment of nanoPP in suspension both in its pristine state, but also when spiked into complex matrices like mineral water and milk.
NanoPP was produced reproducibly in a top-down approach by crushing in acetone with an UltraTurrax, filtering and change of solvent to MilliQ water. The prepared nanoPP material was subjected to a comprehensive physicochemical characterization including e.g., DLS, PTA and AF4-MALS for particle size distribution assessment, PTA and SEM for particle number concentration determination, SEM and AFM for shape analysis and pyrolysis GC-MS for chemical identification. Performed studies showed that the prepared nanoPP material is irregularly shaped and highly polydisperse with a particle size of around 180 nm (e.g., Dh,z-ave from DLS) and a particle size distribution from around 15 nm up to 135 nm (radius of gyration Rg from AF4-MALS).
Storage stability studies using DLS, PTA and AF4-MALS revealed nanoPP in aqueous suspension to be stable for at least 22 months with respect to particle size distribution and number concentration rendering it a promising NP candidate reference material. However, conducted spiking experiments in mineral water and milk showed a time-dependent agglomeration of nanoPP that needs further investigation.
T2 - MICROPLASTICdays
CY - Ljubliana, Slovenia
DA - 03.02.2026
KW - Nanoplastics
KW - Reference materials
PY - 2026
AN - OPUS4-65769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meier, F.
A1 - Altmann, Korinna
T1 - Challenges in nanoplastic analysis: Reference materials, complex matrices, and limits of detection
N2 - The growing concern over nanoplastic particles (< 1 µm) in food and the environment has intensified the need for robust analytical approaches to detect, quantify, and characterize these particles. But the lack is high of standardized and well-characterized reference materials that reflect environmentally relevant nanoplastics according to:
• Size distribution
• Low abundance
• Chemical diversity
• Surface properties
• Behavior in complex matrices.
This poster shows different methods like FFF and AF4-MALS and their results when measuring a nanoPP reference materials candidate.
T2 - Analytica Conference 2026
CY - Munich, Germany
DA - 24.03.2026
KW - Nanoplastics
KW - Reference materials
KW - AF4-MALS
KW - FFF
PY - 2026
AN - OPUS4-65770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Praktikable Prüfung der Wasserstoffverteilung in Mehrlagenschweißungen in Anlehnung an die DIN EN ISO 3690
N2 - Das Forschungsvorhaben adressiert eine zentrale Lücke und damit einhergehende Einschränkung für geschweißte hochfeste Werkstoffe in der aktuellen Normung: Die DIN EN ISO 3690 erlaubt ausschließlich die Bestimmung des diffusiblen Wasserstoffs in einlagigen Prüfraupen und bildet damit die realen Bedingungen in mehrlagigen Schweißnähten hochfester Stähle nicht ab. Durch das mehrfache wiederholte Aufwärmen wird die eingebrachte Wasserstoffkonzentration deutlich unter die konservativen, einlagigen Prüfraupen bereits während des Schweißens abgesenkt. Hierzu fehlt jedoch eine einfache, experimentelle Methoden, um die tatsächliche lokale lagenabhängige bzw. globale Wasserstoffverteilung quantifizieren zu können. Das Vorhaben entwickelt daher erstmals eine Versuchsmethodik, der reale Diffusions- und Entgasungsbedingungen von Mehrlagenschweißungen experimentell reproduziert. Dadurch werden die Nachteile der ISO 3690 (einlagige Prüfraupe, konservative Bewertung) aufgehoben und mit dem Hauptvorteil (robuste, einfache Handhabung) kombiniert. Durch gezielte Variation von Wärmeführung, Zwischenlagentemperaturen und Wasserstoffangebot werden lokale und globale Wasserstoffverteilungen quantifiziert. Ergänzt durch ein numerisches Diffusionsmodell entsteht ein skalierbares Bewertungswerkzeug, das die experimentellen Daten generalisiert und auf reale Schweißnähte überträgt. Die Ergebnisse ermöglichen: (1) eine realitätsnahe Bewertung verbleibender Wasserstoffgehalte, Kaltrisssicherheit, damit die (2) die mögliche Ausweitung der HD Klassifizierung hochfester Schweißzusätze, und (3) die Beurteilung der Effektivität und Notwendigkeit von Wärmenachbehandlungs-maßnahmen (wie „Wasserstoffarmglühen“).
T2 - Sitzung des NA 092-00-05 GA Gemeinschaftsarbeitsausschuss NAS/NMP: Zerstörende Prüfung von Schweißverbindungen (DVS AG Q 4/Q 4.1)
CY - Berlin, Germany
DA - 24.03.2026
KW - Schweißen
KW - Wasserstoff
KW - ISO 3690
KW - Prüfung
KW - Mehrlagennaht
PY - 2026
AN - OPUS4-65784
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Falkenhagen, Jana
A1 - Beskers, Timo. F.
A1 - Myxa, Anett
A1 - Pursch, Matthias
T1 - Round-robin test for size exclusion chromatography – Data summary
N2 - Size exclusion chromatography (SEC or GPC) is one critical component of polymer analysis to meet the increasing requirements in regulatory context – namely, determination of Mn, as well as oligomers of less than 500 g mol-1 and 1000 g mol-1. The underlying test methods (OECD 118/119 and DIN EN ISO 13885 1 to 3) provide a framework for SEC measurements; however, they lack sufficient specificity to obtain accurate results. Previous SEC round robin tests were mostly performed on homopolymers and did not collect data on oligomer contents.
A new round robin test was initiated and conceptualized within the Task force “Method Evaluation for Polymer REACh (MeEP)”, an initiative of “Industrieforum Analytik” within the German Chemical Society (GDCh). Samples for this study were selected to represent both easy benchmark polymers as well as real-life, industry-relevant polymer materials. Data collection focused on the regulatory requirements.
Distribution of samples, gathering of individual results and evaluation were carried out by BAM. A data summary as initial result is reported here. Further evaluation and interpretation are a part of ongoing research.
KW - Size exclusion chromatography
KW - Polymers
KW - Oligomer content
KW - Round-robin test
PY - 2026
DO - https://doi.org/10.26272/opus4-65587
SP - 1
EP - 84
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-65587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weidner, Steffen
T1 - MALDI-TOF MS in der Synthese hochmolekularer Polylaktid Homo- und Copolymere
N2 - Die MALDI-TOF Massenspektrometrie stellt eine wichtige Methode zur simultanen Bestimmung von Molmassen, Molmassenverteilungen und Endgruppen von synthetischen Polymeren dar. In dem Vortrag wird gezeigt, welche zusätzlichen Informationen über die Art der Polymerisation, der Nebenreaktionen und der Topologie der gebildeten hochmolekularen Polylaktid-Homo- und Copolymere im Verlauf ihrer Synthese erhalten werden können.
T2 - Bruker Anwendertreffen
CY - Online meeting
DA - 05.03.2021
KW - MALDI
KW - Polylaktide
PY - 2021
AN - OPUS4-52278
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H. R.
T1 - Sn(II)2-ethylhexanoate-catalyzed polymerizations of L-lactide in solution – Solution grown crystals of cyclic Poly(L-Lactide)s
N2 - L-lactide (LA) was polymerized in toluene by means of neat tin(II) 2-ethylhexanoate (SnOct2). Concentration, time and temperature were varied. The isothermally crystallized polyLAs (PLA) were characterized in the virgin state with regard to topology, molar mass, melting temperature (Tm), crystal modification, high or low Tm morphology, crystallinity and crystal thickness. Even a small amount of solvent favored cyclization relative to polymerization in bulk, so that cyclic polylactides were obtained at 115 ◦C and even at 95 ◦C. At all temperatures the α-modification of PLA was obtained along with crystallinities up to 90%. With 6 M solution the high Tm morphology with Tm’s > 190 ◦C was obtained at 115 ◦C. The crystal thickness of crystallites grown from solution at 115 ◦C was on the average 10–20% higher than that of PLA polymerized in bulk. At a polymerization temperature of 75 ◦C cyclization was incomplete and fewer perfect crystallites were formed. A new hypothesis for the crystal growth of cyclic polyLAs is proposed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
KW - Polymerization
PY - 2022
DO - https://doi.org/10.1016/j.polymer.2022.125142
SN - 0032-3861
VL - 255
SP - 1
EP - 9
PB - Elsevier
CY - Oxford
AN - OPUS4-55283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
A1 - Stolar, Jasna
A1 - Falkenhagen, Jana
A1 - Bhattacharya, Biswajit
A1 - Gugin, Nikita
A1 - Casali, Lucia
T1 - Mechanochemical pathways to sustainability: from molecular insights to applications
N2 - Mechanochemical Innovations for Sustainable Synthesis of Framework Materials and Industrial ScaleUp
Mechanochemistry has emerged as a powerful approach for sustainable materials synthesis and processing, with significant potential to meet the UN Sustainable Development Goals. This presentation will highlight our recent advancements in understanding, monitoring, and scaling-up mechanochemical synthesis of framework materials, focusing on the balance between fundamental understanding of reaction mechanisms and its practical applications in energy storage and energy transfer materials.
A central focus of our work has been the development and application of time-resolved in situ monitoring techniques for mechanochemical processes. Our research on real-time synchrotron X-ray diffraction has enabled unprecedented insights into reaction pathways and kinetics. Recently, we have successfully applied energy-dispersive X-ray diffraction for time-resolved in situ monitoring of reactive extrusion, marking a significant step towards ‘lighting up’ industrial-scale mechanochemistry.
Bridging fundamental understanding with practical applications, we have explored the mechanochemical synthesis of functional materials for energy storage and transfer, making process in the mechanochemical synthesis of highly proton-conductive metal phosphonates, demonstrating the potential of mechanochemistry to manufacture advanced materials for energy applications.
T2 - GDCh Universität Marburg
CY - Marburg, Germany
DA - 10.02.2025
KW - Situ investigation
KW - Nanoparticles
KW - Metal phosphonates
PY - 2025
AN - OPUS4-64844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Falkenhagen, Jana
T1 - Microstructure characterization of oligomers by analysis of UPLC / ESI-TOF-MS reconstructed ion chromatograms
N2 - It is a well-known story that copolymers beside their molar mass distribution (MMD) can exhibit a functionality type distribution (FTD), a copolymer composition distribution (CCD), a monomer sequence distribution (MSD) and additionally different topologies within one sample. Small, often isobaric heterogeneities in topology or microstructure can usually not be simply separated chromatographically or distinguished by any common detector. Nowadays a wide range of different analytical separation techniques and multi-detection possibilities are available. The challenge consists in a clever combination of these techniques with a specific approach of data analysis. In this presentation different liquid chromatographic separation modes were combined with Electrospray Time-of-Flight mass spectrometry.
The online coupling allows the analysis of reconstructed ion chromatograms (RIC) of each degree of polymerization. While a complete separation often cannot be achieved, the derived retention times and peak widths lead to information on the existence and dispersity of heterogeneities in microstructure or topology, that are otherwise inaccessible This method is suitable to detect small differences in e. g. branching, topology, monomer sequence or tacticity and could potentially be used in production control of oligomeric products or other routinely done analyses to quickly indicate deviations from set parameters. Based on a variety of examples e.g. the topology elucidation of branched EO-PO copolymers, the possibilities and limitations of this approach were demonstrated.
T2 - Analyticon 2020
CY - Online meeting
DA - 05.11.2020
KW - Microstructure
KW - Copolymer
KW - LC-MS
PY - 2020
AN - OPUS4-51540
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - ZIF-8-Based Biocomposites via Reactive Extrusion: Towards Industrial-Scale Manufacturing
N2 - Mechanochemistry offers a solvent-free, sustainable alternative to conventional synthesis of metal-organic framework (MOF) biocomposites, which hold great promise for applications in drug delivery, biocatalysis, and biosensing,[1] yet the field remains limited to batch-type, gram-scale processes that restrict industrial application. To overcome these limitations, we present a scalable solid-state method for producing MOF-based biocomposites via continuous reactive extrusion.
The process begins with rapid model reactions using hand-mixing[2] to encapsulate a variety of biomolecules into zeolitic imidazolate framework-8 (ZIF-8), including proteins, carbohydrates, and enzymes, thereby enabling rapid screening and optimization of reaction conditions. The mild synthesis conditions preserve the catalytic activity of glucose oxidase, confirming the suitability of the method to sensitive biomaterials. Building on this, we translated the batch protocol to twin-screw extrusion,[3] enabling continuous and scalable synthesis of biocomposites such as bovine serum albumin (BSA)@ZIF-8 with tunable protein content. The extrusion process yielded highly crystalline, porous materials with protein loadings of up to 26 wt% and encapsulation efficiencies as high as 96%. The production rate reached 1.2 kg d⁻¹, significantly exceeding previously reported continuous methods.[4]
To demonstrate the industrial viability of the method, we extended the approach to produce shaped ZIF-8 monoliths loaded with hyaluronic acid (HA) in a single-step extrusion. These monoliths retained their structural integrity during washing and released HA without measurable degradation, as confirmed by size-exclusion chromatography.
Our study opens new avenues for the industrial implementation of MOF biocomposites and establishes reactive extrusion as a robust platform for their scalable synthesis and shaping, expanding the toolkit for drug delivery and biocatalytical applications.
T2 - Tag der Chemie 2025
CY - Berlin, Germany
DA - 03.07.2025
KW - Mechanochemistry
PY - 2025
AN - OPUS4-63802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Mechanochemical conversion of polyethylene terephthalate into valuable metal-organic frameworks
N2 - Single-use plastics are causing plastic pollution, and less than 10% of plastic waste is recycled globally. Here, we present a sustainable mechanochemical1 protocol for converting post-consumer polyethylene terephthalate (PET) textile and bottles into the porous metal-organic framework (MOF) UiO-66. We used time-resolved in situ synchrotron powder X-ray diffraction and Raman spectroscopy to monitor the depolymerization of PET during ball milling with sodium and potassium hydroxide and water as a liquid additive (Figure 1). For synthesizing UiO-66, we focused on the better performing sodium hydroxide and optimized two distinct synthetic routes to produce high-quality UiO-66. Our results demonstrate the potential of mechanochemistry to enable more circular MOF synthesis using post-consumer PET waste.
T2 - The International Symposium on Mechanochemistry (Mech’cheM) 2025: New forces in Mechanochemistry
CY - Montpellier, France
DA - 04.06.2025
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2025
AN - OPUS4-63943
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H. R.
T1 - Alcohol-initiated and Tin(II) 2-ethylhexanoate-catalyzed polymerization of L-lactide in bulk – About separate crystallization of cyclic and linear Poly (L-lactide)s
N2 - Alcohol-initiated ROPs of L-Lactide were performed at 140 ◦C in bulk with variation of the initiator/catalyst ratio and time. Lower ratios favor the formation of cycles which upon annealing display a change of the MALDI mass peak distribution towards a new maximum with a “saw-tooth pattern” of the mass peaks representing the cycles.
Such a pattern was not observed for the mass peak of the linear chains. The coexistence of these patterns indicate that linear and cyclic poly (L-lactide)s (PLA) crystallize in separate crystals, and that the crystallites of the cycles are made up by extended rings. High Tm and ΔHm values confirm that these extended-ring crystallites represent a thermodynamically optimized form of PLA. Experiments with preformed cyclic and linear PLAs support this interpretation.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
KW - Polymerization
PY - 2023
DO - https://doi.org/10.1016/j.polymer.2023.126355
VL - 285
IS - 126355
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-58355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Dynamics of Composite Materials
N2 - Historically, to tune the properties of a polymer or more general soft matter systems by a second phase is not a new concept and dates back to the 40s of the last century. Beside some successes, the improvement of the properties remained somehow limited. The expectations of the enhancement of the properties of composites changed by the developments of Toyota Central research in the 1990s. It was shown that the incorporation of 5 vol% exfoliated layers of a clay system into a polymer leads to a strong improvement of the mechanical and thermal properties. This discovery stimulated a broad research interest of both fundamental and applied character. Today, polymer-based nanocomposites have reached a billion-dollar global market. The corresponding applications span from components for transportation, commodity plastics with enhanced barrier and/or flame retardancy characteristics, to polymers with electrical properties for shielding, electronics, sensors, and solar cells as well as to live science. Important fields are filled rubbers, reinforced thermoplastics, or thermosets for automotive, aircraft/space and marine industries, but also membranes for separation processes as well as barrier layers, just to mention a few.
For a variety of applications, the molecular mobility in nanocomposites is of great importance. This concerns the molecular mobility needed to form a percolating filler network in rubbers used in tires or in composites employed in electric shielding applications. In general, it is also essential for processing polymer-based nanocomposites. Furthermore, separation processes in composite materials for membranes require a certain molecular mobility. This also concern nanodielectrics used in electrical applications or sensors where the mobility of charge carriers can be related to the fluctuations of molecular groups etc. Finally, the molecular mobility can be taken as probe for structure on a molecular scale.
Broadband dielectric spectroscopy is a powerful tool to investigate the molecular mobility in polymer systems. It is due to the extremely broad frequency and sensitivity range that can be covered by this technique. Information about localized and cooperative molecular fluctuations, polarization effects at interfaces, as well as charge transport processes can be deduced. Therefore, this book focusses on broadband dielectric spectroscopy of composite materials. Moreover, the dielectric studies are accompanied by mechanical spectroscopy, advanced calorimetry, NMR techniques, as well as transmission electron microscopy and X-ray scattering investigations.
Besides a brief introduction to (nano)composites, the book aims to address fundamental aspects of the molecular mobility in this innovative group of materials. Selected examples with scientific interest and some cases with high industrial impact were chosen. Due to the breadth of the subject, unfortunately not all topics could be addressed in detail, such as processing for instance.
Berlin, Andreas Schönhals
July 2021 Paulina Szymoniak
KW - Composite materials
KW - Nanocomposites
PY - 2022
SN - 978-3-030-89722-2
SN - 978-3-030-89723-9
DO - https://doi.org/10.1007/978-3-030-89723-9
VL - 2022
SP - 1
EP - 375
PB - Springer Nature
CY - Cham, Switzerland
AN - OPUS4-54538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emamverdi, Farnaz
T1 - Molecular Mobility and Physical Aging of Polymers with Intrinsic Microporosity (PIM-1) Revisited: A Big Glassy World
N2 - Polymeric membranes represent a cost- and energy-efficient solution for gas separation. Recently Polymers of Intrinsic Microporosity (PIMs) have been in a great interest because of their outstanding BET surface area larger than 700m2/g and pore size smaller than 1 nm. PIMs are a promising candidate in gas separation with high permeability and appealing selectivity due to their inefficient packing derived from a combination of ladder-like rigid segments with sites of contortion. However, it is recognized this class of polymers suffer from decrease in performance with time due to physical aging. The initial microporous structures approach a denser state via local chain rearrangements, leading to a dramatic reduction in permeability. As chain packing during film casting and physical aging are the key factors determine the performance in separation applications, characterization of the molecular mobility in these materials has been proved to provide valuable information. In recent research on PIM-1 the archetypal PIM, a molecular relaxation process with high activation energy together with a significant conductivity in the glassy state has been found and explained with the formation of local intermolecular agglomerates due to interaction of π-electrons in aromatic moieties of the polymer backbone. In this work, the dielectric behavior of the polymeric films and their response upon heating (aging) were measured by isothermal frequency scans during different heating/cooling cycles in a broad temperature range down to 133K for the first time. Multiple dielectric processes following Arrhenius behavior were observed. Local fluctuations, Maxwell-Wagner-Sillars (MWS) polarization and structural relaxations were discussed correlating to structural-properties of PIM-1. Up to now, no other work has studied the role of porosity and thermal history of PIM-1 film in dielectric processes. The goal is by eliminating thermal history and considering storing conditions provide better understanding on aging and plasticizing in high free volume glassy polymer PIM-1.
T2 - IDS Online Meeting
CY - Berlin, Germany
DA - 06.09.2021
KW - Physical Aging
KW - BDS
KW - Microporous structure
KW - Permeation
PY - 2021
AN - OPUS4-55766
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
T1 - Probing Nanoscale Relaxation Behavior in Thin Polymer Films
N2 - The investigations into the complicated effects of film thickness on bulk properties of thin polymer films has yielded conflicting results. The reduction in molecular mobility, and with it an increase in the glass transition temperature, for thin films of poly (bisphenol A carbonate) (PBAC) was assigned to the formation of an adsorbed layer. The adsorbed layer was obtained by washing away the loosely bounded chains using a good solvent. Next, using atomic force microscopy (AFM), the thickness of each sample was measured after annealing for various times at three different annealing temperatures. The growth of this adsorbed layer was shown to deviate from the previously reported 2-step mechanism seen for other polymers. For PBAC, after very long annealing times at high temperatures the thin films were dewetted, where segments of the adsorbed layer were removed from the substrate.
T2 - Royal Society of Chemistry (RSC) Poster
CY - Online meeting
DA - 28.02.2023
KW - Thin films
KW - Adsorbed Layer
KW - Broadband dielectric spectroscopy
KW - Atomic force microscopy
KW - Growth Kinetics
PY - 2023
AN - OPUS4-57196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Friedrich, Alexander
T1 - Simulation data for eddy current rail testing - simulation accuracy and evaluation uncertainty quantification
N2 - This dataset serve to quantify the simulation error and the evaluation uncertainties in the context of eddy current rail testing. It was obtained during the AIFRI project (Artificial Intelligence for Rail Inspection) with the Faraday software by INTEGRATED Engineering Software, using its BEM Solver.
KW - Non-destructive testing
KW - Eddy current testing
KW - Eddy current simulstion
PY - 2024
DO - https://doi.org/10.5281/zenodo.13970374
PB - Zenodo
CY - Geneva
AN - OPUS4-61470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madkour, Sherif A.
A1 - Gawek, Marcel
A1 - Penner, P.
A1 - Paneff, F.
A1 - Zhang, X.
A1 - Gölzhäuser, A.
A1 - Schönhals, Andreas
T1 - Can Polymers be Irreversibly Adsorbed on Carbon Nanomembranes? A Combined XPS, AFM, and Broadband Dielectric Spectroscopy Study
N2 - Carbon nanomembranes are synthetic two-dimensional sheets with nanometer thickness, macroscopic lateral dimensions, and high structural homogeneity. They have great application potential in various branches of nanotechnology. Because of their full carbon structure, it is not clear whether macromolecules like poly(methyl methacrylate) (PMMA) can be irreversibly adsorbed on their surface. Here, irreversible adsorption means that the polymer chains cannot be removed by a leaching process, which is assumed in technological transfer processes. However, if polar defects are present on the carbon nanomembranes (CNMs), it may occur that polymers can be irreversibly adsorbed. To address this question, PMMA was spin-coated on top of CNMs, annealed for a specific time at different temperatures, and then tried to be removed by a acetone treatment in a leaching approach. The samples were investigated in detail by atomic force microscopy, X-ray photoelectron spectroscopy, and broadband dielectric spectroscopy, where the latter method has been applied to CNMs for the first time. Unambiguously, it was shown that PMMA can be adsorbed on the surface of CNMs after annealing the sample above the glasstransition temperature of PMMA. The general occurrence of polar defects on the surface of CNMs and the adsorption of polymers open opportunities for advanced innovative hybrid materials combining the properties of the CNM with those of the polymer.
KW - Carbon Nanomembranes
KW - Irreversible adsorption
KW - Broadband dielectric spectroscopy
KW - XPS spctroscopy
KW - Atomic force microscopy
PY - 2022
DO - https://doi.org/10.1021/acsapm.2c01320
SN - 2637-6105
VL - 4
IS - 11
SP - 8377
EP - 8385
PB - ACS
AN - OPUS4-56067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed Aejaz
A1 - Yildirim, Arda
A1 - Sentker, K.
A1 - Butschies, M.
A1 - Bühlmeyer, A.
A1 - Huber, P.
A1 - Lachat, S.
A1 - Schönhals, Andreas
T1 - Molecular dynamics and electrical conductivity of Guanidinium based Ionic liquid crystals: Influence of cation headgroup configuration
N2 - Molecular mobility and conductivity of four bent shaped tetramethylated guanidinium based ionic liquid crystals (ILCs) with varying head group configuration (cyclic or acyclic) and alkyl chain length is investigated by a combination of broadband dielectric spectroscopy (BDS) and specific heat spectroscopy (SHS). Two dielectrically active processes observed in the plastic crystalline phase at low and high temperatures are denoted as γ and α1 relaxation. The former is assigned to localized fluctuations of methyl groups including nitrogen atoms in the guanidinium head groups. SHS investigations reveal one calorimetrically active process termed as α2 relaxation process. The temperature dependencies of the relaxation rates of α1 and α2 are similar for the cyclic ILC while for the acyclic counterpart they are different. Possible molecular assignments for the α1 and α2 relaxation are discussed in detail. Alongside relaxation processes, a significant conductivity contribution was observed for all ILCs, where the absolute value of DC conductivity increases by 4 orders of magnitude at the transition from the crystalline to the hexagonal columnar phase. The increase is traced to the change in the underlying conduction mechanism from the delocalized electrical conduction in the Cry phase to ionic conduction in the quasi 1D ion columns formed in the hexagonal columnar mesophase.
KW - Ionic liquid crystal
PY - 2021
DO - https://doi.org/10.1016/j.molliq.2021.115666
VL - 330
SP - 115666
PB - Elsevier B.V.
AN - OPUS4-52284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Confinement induced Relaxations and phase behvaiour of nanoconfined Ionic Liquid Crystal
N2 - Ionic Liquid Crystals (ILCs) are materials that combine the properties of liquid crystals together with ionic conduction. It is known that liquid crystal mesophases in confinement exhibit anomalous dynamics and phase behavior. However, similar studies about factors that control the macroscopic properties of ILCs in confinement are limited. Here, Broadband Dielectric Spectroscopy (BDS), X-ray scattering, and calorimetry were applied to study the molecular dynamics, and phase behavior of a guanidinium based columnar ionic liquid crystal confined in self-ordered alumina oxide nanopores of pore sizes ranging from 180 nm down to 25 nm. It is aimed to understand how pore size and pore surface wettability (hydrophilic or hydrophobic) influence the molecular dynamics, and phase behavior for this system which are crucial for applications. The DSC measurements show: (i) the crystalline-liquid crystalline transition temperature has non-monotonic dependence on inverse pore diameter and (ii) the liquid crystalline-isotropic transition is completely suppressed for all the confined samples. This thermally suppressed transition was detected by BDS and X-ray scattering and is considered as a continuous phase transition instead of a discontinuous first order transition. BDS investigations reveal several relaxation processes for the bulk and confined scenarios. The relaxation modes are suppressed and become slower for the confined scenarios compared to the bulk. Possible molecular origins for these relaxation processes are discussed, and it is shown that the self-assembly of these ILCs is dynamic in nature.
T2 - CONFIT 2022
CY - Grenoble, France
DA - 10.10.2022
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2022
AN - OPUS4-57339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kimiaei, E.
A1 - Farooq, M.
A1 - Szymoniak, Paulina
A1 - Ahmadi, Shayan
A1 - Babaeipour, S.
A1 - Schönhals, Andreas
A1 - Österberg, M.
T1 - The role of lignin as interfacial compatibilizer in designing lignocellulosic-polyester composite films
N2 - Advancing nanocomposites requires a deep understanding and careful design of nanoscale interfaces, as interfacial interactions and adhesion significantly influence the physical and mechanical properties of these materials. This study demonstrates the effectiveness of lignin nanoparticles (LNPs) as interfacial compatibilizer between hydrophilic cellulose nanofibrils (CNF) and a hydrophobic polyester, polycaprolactone (PCL). In this context, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using advanced techniques such as quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), water contact angle (WCA) measurements, broadband dielectric spectroscopy (BDS), and inverse gas chromatography (IGC).
QCM-D was employed to quantify the adsorption behavior of LNPs on CNF and PCL surfaces, demonstrating LNPs’ capability to interact with both hydrophilic and hydrophobic phases, thereby enhancing composite material properties. LNPs showed extensive adsorption on a CNF model film (1186 ± 178 ng.cm−2) and a lower but still significant adsorption on a PCL model film (270 ± 64 ng.cm−2). In contrast, CNF adsorption on a PCL model film was the lowest, with a sensed mass of only 136 ± 35 ng.cm−2. These findings were further supported by comparing the morphology and wettability of the films before and after adsorption, using AFM and WCA analyses. Then, to gain insights into the molecular-level interactions and molecular mobility within the composite in dry state, BDS was employed. The BDS results showed that LNPs improved the dispersion of PCL within the CNF network. To further investigate the impact of LNPs on the composites’ interfacial properties, IGC was employed. This analysis showed that the composite films containing LNPs exhibited lower surface energy compared to those composed of only CNF and PCL. The presence of LNPs likely reduced the availability of surface hydroxyl groups, thus modifying the physicochemical properties of the interface. These changes were particularly evident in the heterogeneity of the surface energy profile, indicating that LNPs significantly altered the interfacial characteristics of the composite materials.
Overall, these findings emphasize the necessity to control the interfaces between components for next-generation nanocomposite materials across diverse applications.
KW - Lignin
KW - Nanocomposites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615098
DO - https://doi.org/10.1016/j.jcis.2024.10.083
SN - 0021-9797
VL - 679
SP - 263
EP - 275
PB - Elsevier Inc.
AN - OPUS4-61509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Side Chain length dependent dynamics and conductivity of self assembled ion channels
N2 - We study the molecular mobility and electrical conductivity of a homologous series of linear shaped columnar ionic liquid crystals ILCn, (n = 8, 10, 12, 14, 16) using Broadband Dielectric Spectroscopy (BDS), Specific Heat Spectroscopy (SHS), and X-ray scattering. We aim to understand how the alkyl chain length influences the dynamics and electric conductivity in this system. Two dielectrically active relaxation modes are observed, the and the αcore process, that correspond to the localized relaxation of the alkyl chains, and cooperative motions of the aromatic core in the columns respectively. Both the relaxation and the αcore process slow down with increasing alkyl chain length. SHS reveals one relaxation process, the αalkyl process that has similar temperature dependence as that of the αcore process for ILC12, 14, 16 but shifts to higher temperature for ILC8 and 10. For ILC12, 14, 16 the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. For ILC8, 10 the DC conductivity behavior is similar to ionic liquids, where the conductivity is coupled with structural relaxation. Small-Angle X-ray (SAXS) investigations reveal that both the intercolumnar distance and disorder coherence length increase with alkyl chain length, conversely the DC conductivity decreases monotonically.
T2 - 11th IDS conference 2022
CY - San Sebastian, Spain
DA - 03.09.2022
KW - Glass transition
KW - Conductivity
KW - Fast Scanning Calorimetry
KW - Dynamics
PY - 2022
AN - OPUS4-55878
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Side Chain length dependent dynamics and conductivity of Ionic Liquid crystals
N2 - We investigate the molecular dynamics and electrical conductivity for a homologous series of linear shaped guanidinium based cyclic ILCs that vary in alkyl chain length, CLCRs (R = 8, 10, 12, 14, 16) by employing broadband dielectric spectroscopy (BDS), and calorimetry comprised of Fast Scanning Calorimetry (FSC) and temperature modulated FSC (TMFSC). Besides conductivity at high temperatures, the dielectric dispersion reveals two relaxation modes: the fast γ and the slow α1 relaxation. The former is assigned to the localized fluctuations while the latter is due to segmental dynamics of the alkyl chains. The γ mode slows down for long chain length CLCs (12,14,16) compared to their shorter analogues. Calorimetric investigation reveals one process, the α2 process, for all ILCs. The α2 process for CLC10, 12, and 14 has a similar temperature dependence as the dielectric α1 relaxation, while for the CLC8 and 10, it's shifted to a higher temperature. For all CLCRs, the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. This increase is due to the change in the underlying conduction mechanism from delocalized electron hopping in the crystalline phase to one-dimensional ion mobility in the columnar phase. The glassy dynamics shifts to higher temperatures with increasing alkyl chain length. Conversely, the DC conductivity drops by 3 orders of magnitude from CLC8 to CLC16.
T2 - APS March Meeting 2022
CY - Chicago, IL, USA
DA - 13.03.2022
KW - Glass transition
KW - Conductivity
KW - Fast Scanning Calorimetry
KW - Dynamics
PY - 2022
AN - OPUS4-54760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Schönhals, Andreas
A1 - Böhning, Martin
A1 - Szymoniak, Paulina
ED - Schönhals, Andreas
ED - Szymoniak, Paulina
T1 - (Nano)Composite Materials—An Introduction
N2 - The chapter gives a brief introduction to (nano)compositecomposite materials having the focus on polymer-based nanocomposites. The different dimensionalities of nanoparticles are introduced, along with their distribution in the matrix.
Different application fields of polymer-based nanocomposites, like flame retardancy, filled rubbers, nanofilled thermosets and thermoplastics, separation membranes and nanodielectrics, are considered in greater detail.
KW - Polymer-based nanocomposites
KW - Nanoparticle
KW - Distribution of nanoparticles
KW - Filled rubbers
KW - Filled thermosets and plastics
KW - Separation membranes
KW - Nanodielectrics
PY - 2022
DO - https://doi.org/10.1007/978-3-030-89723-9_1
SP - 1
EP - 31
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-54565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Silbernagl, Dorothee
A1 - Szymoniak, Paulina
A1 - Tavasolyzadeh, Zeynab
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - Interpenetrating networks with tuned thermal and mechanical properties
N2 - Multiphoton lithography (MPL), an emerging microfabrication technique, shows great potential in a variety of applications ranging from tissue engineering to soft micro-robotics. Fabricated micro-objects often are expected to undergo shape morphing or bending. Furthermore, ensuring precise property tuning becomes detrimental for the functionality of MPL microstructures. Herein, we present novel MPL materials based on interpenetrating networks (IPNs), which effectively combine the advantages of acrylate and epoxy thermoset systems. A library of 3D MPL IPN microstructures with high 3D structural stability and tailored thermal and micromechanical properties is achieved. MPL laser velocity and fabrication power can be used to tune the morphology and therefore properties of IPN. New IPN microstructures with materials Young's moduli of 4 to 6 MPa demonstrate susceptibility to deformation with high to fully elastic response. Such soft elastic materials hold immense promise within morphable microsystems, soft micro-robotics and cell engineering applications.
T2 - RSC Poster conference
CY - Online meeting
DA - 05.03.2024
KW - Multiphoton lithography
KW - Interpenetrating polymer networks
KW - AFM
PY - 2024
AN - OPUS4-60060
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Resolving the mystery of the molecular dynamics of epoxy-based materials using broadband dielectric spectroscopy and hypheneated calorimetry
N2 - A detailed calorimetric and dielectric study on two epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) and methyl tetrahydrophtalic acid anhydride (MTHPA) aas the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) and boehmite as nanofiller. The molecular dynamics investigation revealed an intrinsic structural heterogeneity of the epoxy materials. Moreover the polymer/particle interphase was qualitatively and quantitavely investigated.
T2 - Online International Dielectric Society 2020 Workshop
CY - Online meeting
DA - 28.09.2020
KW - Interfaces
KW - Nanocomposites
KW - Rigid amorphous fraction
KW - BDS
KW - TMDSC
PY - 2020
AN - OPUS4-51492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Silbernagl, Dorothee
A1 - Szymoniak, Paulina
A1 - Tavasolyzadeh, Zeynab
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - Interpenetrating Polymer Networks with Tuned Thermal and Mechanical Properties by Multiphoton Lithography
N2 - Multiphoton lithography (MPL) has recently attracted significant research interest as a versatile tool capable of fabricating 2D and 3D micro- and nanoscopic features with high spatial resolution. The integrity of MPL microstructures, or their ability to respond to external stimuli, is of critical importance. Often, the mechanically flexible micro-objects are expected to be capable of shape morphing, bending, or other motion to ensure their functionality. However, achieving the desired properties of MPL-manufactured micro components for a specific application still remains challenging.
In this work, we present new MPL materials based on epoxy-acrylate interpenetrating networks (IPNs). We aim at fabrication 3D microstructures, whose properties can be easily tuned by varying the ratio of the IPN components and fabrication parameters. The studied mixtures consist of polyethylene glycol diacrylate (PEGDA) and cycloaliphatic epoxide functional groups. Consequently, tryarylsylfonium salt and cyclopentanone photoinitiator tailored for MPL were used to ensure cationic and radical polymerization, respectively. The resulting library of 3D microstructures was investigated for their thermal and mechanical properties using highly sensitive space-resolved methods. For the first time, we were able to evaluate the glass transition behavior of 3D MPL microstructures using fast scanning calorimetry. The influence of both IPN composition and fabrication parameters on glass transition temperature and material fragility was demonstrated. AFM force-distance curve and intermodulation methods were used to characterize the micromechanical properties with lateral resolution of the techniques in the range of 1 micron and 4 nm, respectively. The elastic-plastic behavior of the microarchitectures was evaluated and explained in terms of IPN morphology and thermal properties. The fabricated 3D IPN microstructures exhibit higher structural strength and integrity compared to PEGDA. In addition, IPNs exhibit high to full elastic recovery (up to 100%) with bulk modulus in the range of 4 to 6 MPa. This makes IPNs a good base material for modeling microstructures with intricate 3D designs for biomimetics and scaffold engineering.
The effects of composition and MPL microfabrication parameters on the resulting IPN properties give us a better understanding of the underlying mechanisms and microfabrication-structure-property relationships. Moreover, our funding supports the further development of IPN systems as versatile and easily tunable MPL materials.
T2 - Material Research Society Meeting
CY - Boston, Massachusetts, USA
DA - 26.11.2023
KW - Multiphoton Lithography
KW - Two-photon polymerisatio
KW - Interpenetrating polymer network
PY - 2023
SP - 1
AN - OPUS4-59382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Denkler, Tilman
T1 - The Metabuilding Labs approach to Quality Assurance – Results of Task 8.4 & Task 8.5
N2 - The finalization of the Standard Operating Procedures and Work Instructions for the O3BETs is described. The setuo of the internal system for quality checks is outlined. Major achievements are shown and future work is adressed.
T2 - 7th General Meeting Metabuilding Labs
CY - Bordeaux, France
DA - 20.5.2025
KW - Metabuilding Labs
KW - Open innovation test bed
KW - Quality management
PY - 2025
AN - OPUS4-63299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emamverdi, Farnaz
T1 - Molecular mobility and gas transport properties of mixed matrix membranes based on PIM-1 and POF fillers
N2 - Especially now in times of the energy revolution, the demand for energy-efficient separation processes promotes the advancement of new high-performance materials for use as highly selective separation membranes. Polymers with intrinsic microporosity (PIMs) are of high interest in the field of gas separation membranes. Currently the application of PIMs for membrane technology is still restrained by their strong tendency to physical aging involving a significant loss of their good gas separation properties. Physical aging phenomenon is related to the molecular mobility of PIMs which was investigated by broadband dielectric spectroscopy (BDS) previously [1]. In this work, covalent phosphinine-based framework (Eto-CPSF) was used as a nanofiller (0-10 wt %) in a PIM-1 matrix to potentially enhance the gas transport properties and prevent physical aging. Since molecular mobility is a fundamental parameter determining gas transport as well as physical aging in such a material, our study includes dielectric investigations by BDS of pure PIM-1 and PIM-1/Eto-CPSF mixed matrix membranes to establish a correlation between molecular mobility and gas transport properties. In addition, gas permeability was determined by the time-lag method (0-10 bar pressure) at 35 °C for N2, O2, CH4 and CO2 for all MMMs.
The dielectric behavior of the polymeric films and their response upon heating were measured by isothermal frequency scans during different heating/cooling cycles in a broad temperature range up to 250 °C. Multiple dielectric processes following Arrhenius behavior were observed. Local fluctuations, Maxwell-Wagner-Sillars (MWS) polarization and structural relaxations were discussed correlating to structural-properties of PIM-1. As main result for MMMs, the permeability of PIM-1 for CH4 and CO2 gases were increased significantly with only 5 wt% of nanofiller within the polymer matrix. However, this is not observed for Eto-CPSF concentrations higher than ca. 7 wt% probably due to a microphase separated morphology of the nanocomposite system. Furthermore, the permselectivity of membranes for pair gases O2/N2 and CO2/N2 show enhancement up to a concentration of about 7 wt% Eto-CPSF filler.
T2 - 11th BDS conference
CY - San Sebastian, Spain
DA - 04.09.2022
KW - Gas transport
KW - BDS
KW - Mixed Matrix Membrane
KW - Nanocomposite
PY - 2022
AN - OPUS4-55752
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grunwald, M. A.
A1 - Hagenlocher, S. E.
A1 - Turkanovic, L.
A1 - Bauch, S. M.
A1 - Wachsmann, S. B.
A1 - Altevogt, L. A.
A1 - Ebert, M.
A1 - Knöller, J. A.
A1 - Raab, A. R.
A1 - Schulz, F.
A1 - Kolmangadi, Mohamed A.
A1 - Zens, A.
A1 - Huber, P.
A1 - Schönhals, Andreas
A1 - Bilitiewski, U.
A1 - Laschat, S.
T1 - Does thermotropic liquid crystalline self-assembly control biological activity in amphiphilic amino acids? – tyrosine ILCs as a case study
N2 - Amphiphilic amino acids represent promising scaffolds for biologically active soft matter. In order to understand the bulk self-assembly of amphiphilic amino acids into thermotropic liquid crystalline phases and their biological properties a series of tyrosine ionic liquid crystals (ILCs) was synthesized, carrying a benzoate unit with 0–3 alkoxy chains at the tyrosine unit and a cationic guanidinium head group. Investigation of the mesomorphic properties by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (WAXS, SAXS) revealed smectic A bilayers (SmAd) for ILCs with 4-alkoxy- and 3,4-dialkoxybenzoates, whereas ILCs with 3,4,5-trisalkoxybenzoates showed hexagonal columnar mesophases (Colh ), while different counterions had only a minor influence. Dielectric measurements revealed a slightly higher dipole moment of non-mesomorphic tyrosine-benzoates as compared to their mesomorphic counterparts. The absence of lipophilic side chains on the benzoate unit was important for the biological activity. Thus, non-mesomorphic tyrosine benzoates and crown ether benzoates devoid of additional side chains at the benzoate unit displayed the highest cytotoxicities (against L929 mouse fibroblast cell line) and antimicrobial activity (against Escherichia coli DTolC and Staphylococcus aureus) and promising selectivity ratio in favour of antimicrobial activity.
KW - Liquid Crystals
PY - 2023
DO - https://doi.org/10.1039/d3cp00485f
SN - 1463-9076
VL - 25
IS - 26
SP - 17639
EP - 17656
PB - RCS
AN - OPUS4-57796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Denkler, Tilman
T1 - Status of task 8.5 - quality assurance
N2 - The presentation was given at the virtual general meeting of the Horizon 2020 project "Metabuilding Labs" to inform the partners about the status of the development of the quality management documentation of MBLabs.
T2 - Metabuilding Labs General Meeting March 8th & 9th
CY - Online meeting
DA - 8.3.2023
KW - Quality Management
KW - Metabuilding Labs
PY - 2023
AN - OPUS4-57122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy and advanced calorimetry
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n = 5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations probing the molecular mobility, a c-relaxation due to localized fluctuations as well as two glassy dynamics, the acore- and aalkyl-relaxation, were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n = 8 from a rigid constrained (n = 5,6) to a softer system (n = 10,12) was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene-like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition.
KW - Discotic liquid crystals
KW - Broadband dielectric spectroscopy
KW - Advanced calorimetry
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2022.119212
VL - 358
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-54721
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Confinement induced relaxations and phase behavior of a nanoconfined ionic liquid crystal
N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing phase transition behaviors and relaxation dynamics. Here in, we investigate the molecular dynamics and electrical conductivity of a linear shaped guanidinium based ILC confined in self-ordered nano porous alumina oxide membranes of pore size ranging from 180nm down to 25nm by employing broadband dielectric spectroscopy (BDS) and calorimetry. Calorimetric investigation reveals a complete suppression of the columnar – isotropic transition, while the plastic crystalline – columnar transition temperature decreases with inverse pore size and deviates from the Gibbs – Thomson equation.
For the bulk case, BDS detects two relaxation modes in the crystalline phase, the relaxation and the α1 relaxation, and two relaxation modes in the columnar phase, the α2 and α3 relaxation. For the confined case, all relaxation modes slow down compared to the bulk. However, for the least pore size (25 nm), the α2 relaxation is absent. We discuss the possible molecular origins of the different relaxation modes observed. For the bulk ILC, a clear jump of 4 orders of magnitude in the absolute values of DC conductivity occurs at the transition from the plastic crystalline to hexagonal columnar phase, for the confined ILC, this transition is smooth. DC conductivity is reduced for the confined case, except for the 25nm, where the values is similar to the bulk.
T2 - 11th IDS conference 2022
CY - San Sebastian, Spain
DA - 03.09.2022
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2022
AN - OPUS4-55879
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pleskunov, P.
A1 - Nikitin, D.
A1 - Tafiichuk, R.
A1 - Shlemin, A.
A1 - Hanus, J.
A1 - Kousal, J.
A1 - Krtous, Z.
A1 - Khalakhan, I.
A1 - Kus, P.
A1 - Nasu, T.
A1 - Nagahama, T.
A1 - Funaki, C.
A1 - Sato, H.
A1 - Gawek, Marcel
A1 - Schönhals, Andreas
A1 - Choukourov, A.
T1 - Plasma polymerization of acrylic acid for the tunable synthesis of glassy abd carboxylated nanoparticle
N2 - Polymer nanoparticles (NPs) can be highly attractive in numerous applications including biomedicine where the use of inorganic matter may be detrimental for living tissues. In conventional wet chemistry, polymerization and functionalization of NPs with specific chemical groups involves complex and often numerous reactions. Here, we report on a solvent-free, single-step, low temperature plasma-based synthesis of carboxylated NPs produced by polymerization of acrylic acid under the conditions of a glow discharge. In a monomer-deficient regime, strong fragmentation of the monomer molecules by electron impact results in the formation of 15 nm-sized NPs with <1% retention of the carboxyl groups. In an energy-deficient regime, larger 90 nm-sized NPs are formed with better retention of the carboxyls that reaches 16 %. All types of the NPs exhibit the glass transition above the room temperature which makes them highly stable under aqueous environment with no dissolution or swelling. They are also found to degrade thermally when heated above 150 °C with a decrease of the mean NP size, yet with the retention of the chemical composition. Thus, plasma polymerization proves to be a versatile approach for the production of polymer NPs with tuneable size distribution, chemical composition and physical properties.
KW - Nanoparticles
PY - 2020
DO - https://doi.org/10.1021/acs.jpcb.9b08960
VL - 124
SP - 668
EP - 678
PB - ACS
AN - OPUS4-50351
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hernández García, María Amparo
T1 - Optical biosensor using free form prototyped elements for targeted explosives immunodetection
N2 - Ensuring the safety and security of citizens necessitates a considerable investment of resources and the development of innovative tools by national and international agencies and governments, particularly in the context of explosives detection [1]. The necessity for the detection of improvised explosive devices (IEDs) and homemade explosives (HMEs) at the point of suspicion has increased exponentially due to the simplicity with which the precursors can be obtained, and the reagents synthesised. The restricted availability of immunoanalytical instruments for the detection of homemade explosives (HMEs) offers a valuable opportunity for the development of innovative devices that can rapidly identify and recognise the target analyte with high specificity and sensitivity [2].
In this study, we present the development of an optical biosensor for highly specific and sensitive HME detection. The immunoassay system is situated within a matrix that is permeable to the target analyte and transparent to light, which enables the interrogation via fluorescence. The immunoanalytical system's readout is achieved through the utilisation of supercritical angle fluorescence (SAF), an advanced microscopy technique. To this end, we employed recent, commercially available high-resolution (less than 22 μm) liquid crystal display SLA printers to fabricate a free-form parabolic optical element with a high refractive index (RI greater than 1.5) and transmission values exceeding 90% from commercial photo-resins. The objective is to develop a new generation of sensors that can not only meet the requirements of trace detection but also be used for substance identification. The combination of immunoanalytical recognition with SAF detection offers a modular and versatile solution that is particularly well suited to the measurement of target analytes at trace levels.
T2 - ANAKON 2025
CY - Leipzig, Germany
DA - 10.03.2025
KW - Biosensor
KW - SAF
KW - Free-form optics
KW - 3D printing
KW - Security
PY - 2025
AN - OPUS4-62802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cano Murillo, Natalia
A1 - Szymoniak, Paulina
A1 - Smales, Glen Jacob
A1 - Sturm, Heinz
A1 - Schönhals, Andreas
T1 - Electrospun nanocomposites fibers of polycarbonate and taurine modified boehmite nanoparticles - What can be learned from structural and thermal investigations
N2 - Though the reinforcing properties of inorganic particles in thermosetting nanocomposites, has been exploited, the integration of nanoparticles continues to be challenging in terms of their homogeneous distribution and their manipulation which can contribute to occupational hazards. Due to a second encapsulations of nanoparticles, electrospun nanocomposite fibers containing nanoparticles might be an alternative for overcoming these issues, as the fiber nonwovens contains the nanoparticles allowing for safer manipulation. Here, the morphology, and the thermal properties of electrospun polycarbonate fibers containing taurine modified boehmite nanoparticles (BNP) are investigated by means of small and wide-angle X-ray scattering as well as fast scanning and temperature modulated fast scanning calorimetry for the first time. The latter techniques allow the investigation of the thermal properties of single fibers at heating rates up to 10^4 K s^-1 keeping its structure intact. A quantitative analysis of the scattering data reveals a porous structure of the fibers. The porous structure is quantified regarding the pore volume and the pore size. A constant amount of aggregation is found even for the highly BNP loaded fibers. Thermal analysis on the fibers reveals a rigid amorphous fraction (RAF) where it is known that RAF determinates the properties of a nanocomposite to a large extent. For the fibers RAF amounts up to 40 wt%, which is essential higher compared to equally formulated PC/BNP composite cast films. The RAF in the case of the fibers, is not only due to the presence of particles in the polymer but also due to orientation effects induced by the electrospinning process.
KW - Nanocomposite fibers
KW - Electrospinning
KW - X-ray scattering
KW - Fast scanning calorimetry
KW - Rigid amorphous fraction
PY - 2021
DO - https://doi.org/10.1021/acsapm.1c01265
VL - 3
IS - 12
SP - 6572
EP - 6585
PB - ACS
AN - OPUS4-53871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation
N2 - We report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all Poly(tricyclononenes) with Si(OR)3 side groups, which is interpreted in terms of a percolation model.
T2 - IDS Online conference 2021
CY - Online meeting
DA - 06.09.2021
KW - Glass transition
KW - Conductivity
KW - Dynamics
KW - Fast Scanning Calorimetry
PY - 2021
AN - OPUS4-53299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - ILC Meeting
N2 - We summarized our recent findings about the molecular dynamics investigation of bulk and finite ionic liquid crystals. We investigate the molecular dynamics and electrical conductivity for a homologous series of linear shaped guanidinium based cyclic ILCs that vary in alkyl chain length, CLCRs (R = 8, 10, 12, 14, 16) by employing broadband dielectric spectroscopy (BDS), and calorimetry comprised of Fast Scanning Calorimetry (FSC) and temperature modulated FSC (TMFSC). Besides conductivity at high temperatures, the dielectric dispersion reveals two relaxation modes: the fast γ and the slow α1 relaxation. The former is assigned to the localized fluctuations while the latter is due to segmental dynamics of the alkyl chains. The γ mode slows down for long chain length CLCs (12,14,16) compared to their shorter analogues. Calorimetric investigation reveals one process, the α2 process, for CLC12,14 and 16 and two processes, α2 and α3, for CLC8 and 10. The α2 process of all CLCRs has a similar temperature dependence as the dielectric α1 relaxation, which indicates both BDS and FSC probe the segmental dynamics of alkyl side chains, as observed for the bent shaped cyclic ILCs. We interpret the α3 process of CLC8 and 10 as the segmental dynamics of the cation core. For all CLCRs, the absolute values of DC conductivity increase by 4 orders of magnitude at the transition from the plastic crystalline to hexagonal columnar phase. This increase is due to the change in the underlying conduction mechanism from delocalized electron hopping in the crystalline phase to one dimensional ion mobility in the columnar phase. The glassy dynamics shifts to higher temperatures with increasing alkyl chain length. Conversely, the DC conductivity drops by 3 orders of magnitude from CLC8 to CLC16.
T2 - ILC Project Meeting
CY - Berlin, Germany
DA - 14.09.2021
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2021
AN - OPUS4-53675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Glass transition, glassy dynamics and electrical conductivity of guanidinium based ILCS: Influcence of the cation headgroup configuration
N2 - Molecular mobility and conductivity of four bent shaped tetramethylated guanidiniumbased ionic liquid crystals(ILCs) with varying head group configuration (cyclic or acyclic) and alkyl chain length is investigated by a combination of broadband dielectric spectroscopy (BDS) and specific heat spectroscopy (SHS). Two dielectrically active processes observed in the plastic crystalline phase at low and high temperatures are denoted as γ and α1 relaxation. The former is assigned to localized fluctuations of methyl groups including nitrogen atoms in the guanidinium head groups. SHS investigations reveal one calorimetrically active process termed as α2 Relaxation process. The temperature dependencies of the relaxation rates of α1 and α2 are similar for the cyclic ILCwhile for the acyclic counterpart they are different. Possible molecular assignments for the α1 and α2 relaxation are discussed in detail. Alongside relaxation processes, a significant conductivity contribution was observed for all ILCs, where the absolute value of DC conductivity increases by 4 orders of magnitude at the transition from the crystalline to the hexagonal columnar phase. The increase is traced to the change in the underlying conduction mechanism from the delocalized electrical conduction in the Cry phase to ionic conduction in the quasi 1D ion columns formed in the hexagonal columnar mesophase.
T2 - DPG Online Spring Conference 2021
CY - Online meeting
DA - 22.03.2021
KW - Fast Scanning Calorimetry
KW - Glass transition
KW - Conductivity
KW - Dynamics
PY - 2021
AN - OPUS4-52336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Phase Behaviour and Molecular Mobility of a confined Ionic Liquid Crystal
N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing orientational order and phase transition behaviors. Here, the plastic crystal to hexagonal columnar, and hexagonal columnar to isotropic transition temperatures are studied for the guanidinium-based ionic discotic liquid crystal confined in self- ordered nanoporous alumina membranes. The phase transition temperature of the plastic crystal to hexagonal columnar phase is reduced with inverse pore diameter. The hexagonal columnar to isotropic transition is suppressed completely in all pores and a possible explanation is given. The results are of technological relevance for the design of liquid crystal-based devices such as batteries and sensors with optimum tunable properties.
T2 - Interpore Konferenz
CY - Online meeting
DA - 31.05.2021
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2021
AN - OPUS4-53298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
ED - Schönhals, Andreas
ED - Szymoniak, Paulina
T1 - Epoxy-Based Nanocomposites—What Can Be Learned from Dielectric and Calorimetric Investigations?
N2 - Epoxy-based nanocomposites are promisingmaterials for industrial applications (i.e., aerospace, marine, and automotive industries) due to their extraordinary mechanical and thermal properties. Regardless of the broad field of applications, there is still a considerable need to identify their structure–property relationships. Here, a detailed dielectric and calorimetric (DSC and fast scanning calorimetry) study on different epoxy-based nanocomposites was performed. Bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) was employed as the polymeric matrix, which was reinforced with three diverse nanofillers that exhibit different interaction strengths with the epoxy matrix (halloysite nanotubes, surface modified halloysite nanotubes, and taurine-modified layered double hydroxide). The structure, molecular mobility, and vitrification behavior are discussed in detail, focusing on the intrinsic structural and dynamic heterogeneity, as well as interfacial properties.
KW - Nanocomposites
KW - Epoxi nanocomposites
KW - Dynamics
KW - Interphase
KW - Ridis amorphous fraction
KW - Dielectric spectroscopy
KW - Flash DSC
KW - Temparatur modulated Flash DSC
KW - Temperature modulated DSC
PY - 2022
DO - https://doi.org/10.1007/978-3-030-89723-9_11
SP - 335
EP - 367
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-54566
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Qu, Xintong
A1 - Abbasi, M.
A1 - Pauw, Brian Richard
A1 - Henning, S.
A1 - Li, Z.
A1 - Wang, D.-Y.
A1 - Schick, C.
A1 - Saalwächter, K.
A1 - Schönhals, Andreas
T1 - Spatial inhomogeneity, Interfaces and Complex Vitrification Kinetics in a Network Forming Nanocomposite
N2 - A detailed calorimetric study on an epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) as the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) as nanofiller. The -NH2 group of taurine can react with DGEBA improving the interaction of the polymer with the filler. The combined X-ray scattering, and electron microscopy data showed that the nanocomposite has a partially exfoliated morphology. Calorimetric studies were performed with conventional DSC, temperature modulated DSC (TMDSC) and fast scanning calorimetry (FSC) in the temperature modulated approach (TMFSC) to investigate the vitrification and molecular mobility in dependence of the filler concentration. First, TMDSC and NMR were used to estimate the amount of the rigid amorphous fraction which consists of immobilized polymer segments at the nanoparticle surface. It was found to be 40 wt% for the highest filler concentration, indicating that the interface dominates the overall macroscopic properties and behavior of the material to a great extent. Second, the relaxation rates of the α-relaxation obtained by TMDSC and TMFSC were compared with the thermal and dielectric relaxation rates measured by static FSC. The investigation revealed that the system shows two distinct α-relaxation processes. Furthermore, also two separate vitrification mechanisms were found for a bulk network-former without geometrical confinement as also confirmed by NMR. This was discussed in terms of the intrinsic spatial heterogeneity on a molecular scale, which becomes more pronounced with increasing nanofiller content.
KW - Polymer based Nanocomposites
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523199
DO - https://doi.org/10.1039/d0sm01992e
SN - 1744-6848
VL - 17
IS - 10
SP - 2775
EP - 2790
PB - Royal Society of Chemistry
AN - OPUS4-52319
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Z.
A1 - Raab, A.
A1 - Kolmangadi, Mohamed Aejaz
A1 - Busch, M.
A1 - Grunwald, M.
A1 - Demel, F.
A1 - Bertram, F.
A1 - Kityk, A. V.
A1 - Schönhals, Andreas
A1 - Laschat, S.
A1 - Huber, P.
T1 - Self-Assembly of Ionic Superdiscs in Nanopores
N2 - Discotic ionic liquid crystals (DILCs) consist of self-assembled superdiscs of cations and anions that spontaneously stack in linear columns with high one-dimensional ionic and electronic charge mobility, making them prominent model systems for functional soft matter. Compared to classical nonionic discotic liquid crystals, many liquid crystalline structures with a combination of electronic and ionic conductivity have been reported, which are of interest for separation membranes, artificial ion/proton conducting membranes, and optoelectronics. Unfortunately, a homogeneous alignment of the DILCs on the macroscale is often not achievable, which significantly limits the applicability of DILCs. Infiltration into nanoporous solid scaffolds can, in principle, overcome this drawback. However, due to the experimental challenges to scrutinize liquid crystalline order in extreme spatial confinement, little is known about the structures of DILCs in nanopores. Here, we present temperaturedependent high-resolution optical birefringence measurement and 3D reciprocal space mapping based on synchrotron X-ray scattering to investigate the thermotropic phase behavior of dopamine-based ionic liquid crystals confined in cylindrical channels of 180 nm diameter in macroscopic anodic aluminum oxide membranes. As a function of the membranes’ hydrophilicity and thus the molecular anchoring to the pore walls (edge-on or face-on) and the variation of the hydrophilic−hydrophobic balance between the aromatic cores and the alkyl side chain motifs of the superdiscs by tailored chemical synthesis, we find a particularly rich phase behavior, which is not present in the bulk state. It is governed by a complex interplay of liquid crystalline elastic energies (bending and splay deformations), polar interactions, and pure geometric confinement and includes textural transitions between radial and axial alignment of the columns with respect to the long nanochannel axis. Furthermore, confinement-induced continuous order formation is observed in contrast to discontinuous first-order phase transitions, which can be quantitatively described by Landau-de Gennes free energy models for liquid crystalline order transitions in confinement. Our observations suggest that the infiltration of DILCs into nanoporous solids allows tailoring their nanoscale texture and ion channel formation and thus their electrical and optical functionalities over an even wider range than in the bulk state in a homogeneous manner on the centimeter scale as controlled by the monolithic nanoporous scaffolds.
KW - Ionic Liquid Crystals
KW - Nanopropous materials
KW - Landau de-Gennes analysis
KW - X-ray scattering
KW - Optical birefringence
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600797
DO - https://doi.org/10.1021/acsnano.4c01062
SN - 1936-0851
VL - 18
IS - 22
SP - 14414
EP - 14426
PB - ACS
AN - OPUS4-60079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nikitin, D.
A1 - Biliak, K.
A1 - Protsak, M.
A1 - Adejube, B.
A1 - Ali-Ogly, S.
A1 - Škorvanková, K.
A1 - Červenková, V.
A1 - Katuta, R.
A1 - Tosco, M.
A1 - Hanuš, J.
A1 - Černochová, Z.
A1 - Černoch, P.
A1 - Štěpánek, P.
A1 - Boiko, O.
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Faupel, F.
A1 - Biedermann, H.
A1 - Vahl, A.
A1 - Choukourov, A.
T1 - Unveiling the Fundamental Principles of Reconfigurable Resistance States in Silver/Poly(ethylene glycol) Nanofluids
N2 - Developing novel memristive systems aims to implement key principles of biological neuron assemblies – plasticity, adaptivity, and self-organization – into artificial devices for parallel, energy-efficient computing. Solid-state memristive devices, such as crossbar arrays and percolated nanoparticle (NP) networks, already demonstrate these properties. However, closer similarity to neural networks is expected from liquid-state systems, including polymer melts, which remain largely unexplored. Here, the resistive switching in silver/poly(ethylene glycol) (Ag/PEG) nanofluids, prepared by depositing gas-aggregated Ag NPs into PEGs of varying molecular mass, is investigated.
These systems form long-range conductive NP bridges with reconfigurable resistance states in response to an electric field. The zeta-potential of Ag NPs and molecular mobility of PEG determine the prevalence of low resistance (ohmic) state, high resistance states (poor conductance) or intermediate transition states governed by space-charge-limited conduction or electron tunneling. The occurrence of these states is given by the interparticle gaps, which are determined by the conformation of PEG molecules adsorbed on the NPs. It is presented, for the first time, an equivalent circuit model for the Ag/PEG system. These findings pave the way to adopt polymer melts as matrices for neuromorphic engineering and bio-inspired electronics.
KW - Nanofluids
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635351
DO - https://doi.org/10.1002/advs.202505103
VL - 12
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-63535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Ahamadi, Shayan
A1 - Hülagü, Deniz
A1 - Hidde, Gundula
A1 - Hertwig, Andreas
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Investigations of the adsorbed layer of polysulfone: Influence of the thickness of the adsorbed layer on the glass transition of thin films
N2 - This work studies the influence of the adsorbed layer on the glass transition of thin films of polysulfone. Therefore, the growth kinetics of the irreversibly adsorbed layer of polysulfone on silicon substrates was first investigated using the solvent leaching approach, and the thickness of the remaining layer was measured with atomic force microscopy. Annealing conditions before leaching were varied in temperature and time (0–336 h). The growth kinetics showed three distinct regions: a pre-growth step where it was assumed that phenyl rings align parallel to the substrate at the shortest annealing times, a linear growth region, and a crossover from linear to logarithmic growth observed at higher temperatures for the longest annealing times. No signs of desorption were observed, pointing to the formation of a strongly adsorbed layer.
Second, the glass transition of thin polysulfone films was studied in dependence on the film thickness using spectroscopic ellipsometry. Three annealing conditions were compared: two with only a tightly bound layer formed in the linear growth regime and one with both tightly bound and loosely adsorbed layers formed in the logarithmic growth regime. The onset thickness and increase in the glass transition temperature increases with annealing time and temperature. These differences were attributed to the distinct conformations of the formed adsorbed layers.
KW - Glass transition
KW - Adsorbed Layer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607701
DO - https://doi.org/10.1063/5.0223415
SN - 0021-9606
VL - 161
IS - 5
SP - 1
EP - 12
PB - AIP Publishing
AN - OPUS4-60770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Juranyi, F.
A1 - Kruteva, M.
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Low-Frequency Vibrational Density of States of Nanophase- Separated Poly(n‑alkyl methacrylate)s: Confined Phonons and Relationship to Specific Heat
N2 - This study investigates the low-frequency vibrational Density of states of nanophase-separated poly(n-alkyl methacrylate)s (PnMAs) and its relationship to specific heat. This system undergoes a nanophase separation for n > 1 in alkyl side chain-rich domains and a backbone-rich matrix. Using inelastic neutron scattering, the low-frequency vibrational density of states (Boson peak, BP) of PnMAs with varying alkyl side chain lengths (methyl, butyl, hexyl, and octyl) is measured. The results reveal that the BP shifts to higher frequencies with increasing side chain length reaching a maximum. This result indicates a counterbalance of confinement effects and the scattering of the matrix. The behavior of the Boson peak of the PnMAs is compared to other nanophase-separated systems, such as Janus-polynorbornenes and hexakis(n-alkyloxy)triphenylene discotic liquid crystals. The study also explores the connection between the BP and specific heat capacity, showing a linear relationship between the maximum frequency of the BP and the maximum temperature of the specific heat capacity anomaly. Moreover, from the measured vibrational density of states, the specific heat capacity is calculated and compared to experimental results. The comparison reveals qualitative agreement between the calculated and experimental data. These findings provide evidence for the sound wave interpretation of the Boson peak.
KW - Inelastic Neutron Scattering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636928
DO - https://doi.org/10.1021/acs.macromol.5c00898
SN - 1520-5835
SP - 1
EP - 12
PB - ACS Publications
AN - OPUS4-63692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Böhning, Martin
A1 - De Souza, N. R.
A1 - Juranyi, F.
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Inelastic and Quasielastic Neutron Scattering on Polynorbornenes with Bulky Carbocyclic Side groups
N2 - This study investigates the molecular mobility and vibrational properties of polynorbornenes with bulky carbocyclic side groups using inelastic and quasielastic neutron scattering techniques. The polymers, synthesized via metathesis and addition polymerization, exhibit varying degrees of microporosity, which ignificantly influences their gas separation performance. By inelastic neutron scattering experiments, it could be shown that all considered polymers have excess contributions to the low frequency vibrational density of states known as the Boson peak. The maximum frequency of the Boson peak correlates to the microporosity of the polymers.
This correlation supports the sound wave interpretation of the Boson peak, suggesting that the microporous structure enhances the compressibility of the material at a microscopic length scale. The molecular mobility, particularly the methyl group rotation, was characterized using elastic scans and quasielastic neutron scattering. The study revealed a temperature dependent relaxation process, with the onset of molecular fluctuations observed around 200 K for the polymer containing methyl groups. For the polymer having no methyl groups only elastic scattering is observed. The methyl group rotation was analyzed in terms of a jump diffusion in a threefold potential with three equivalent energy minima. This leads to an almost correct description of the q dependence of the elastic incoherent scattering function when the number of hydrogen nuclei undergoing the methyl group rotation is considered. It was further evidenced that the fraction of methyl undergoing the methyl group rotation increases with increasing temperature.
KW - Polymers of Intrinsic Microporosity
KW - Neutron scattering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630297
DO - https://doi.org/10.1016/j.polymer.2025.128358
SN - 1873-2291
VL - 328
SP - 241
PB - Elsevier Ltd.
AN - OPUS4-63029
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Ahmadi, Shayan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Molecular Mobility of Thin Films of Poly (bisphenol-A carbonate) Capped and with one Free Surface: From Bulk-like Samples down to the Adsorbed Layer
N2 - The molecular mobility of thin films of poly(bisphenol A carbonate) (PBAC) was systematically investigated using broadband dielectric spectroscopy, employing two distinct electrode configurations. First, films were prepared in a capped geometry between aluminum electrodes employing a crossed electrode capacitor (CEC) configuration, down to film thicknesses of 40 nm. The Vogel temperature, derived from the temperature dependence of relaxation rate of the α-relaxation, increases with decreasing film thickness characterized by an onset thickness. The onset thickness depends on the annealing conditions, with less intense annealing yielding a lower onset thickness. Additionally, a broadening of the β-relaxation peak was observed with decreasing thickness, attributed to the interaction of phenyl groups with thermally evaporated aluminum, resulting in a shift of certain relaxation modes to higher temperatures relative to the bulk material. A novel phenomenon, termed the slow Arrhenius process (SAP), was also identified in proximity to the α-relaxation temperature.
For films with thicknesses below 40 nm, nanostructured electrodes (NSE) were utilized, incorporating nanostructured silica spacers to establish a free surface with air. This free surface causes an enhancement in the molecular mobility for the 40 nm sample, preserving the β-relaxation as a distinct peak. The α-relaxation was detectable in the dielectric loss down to 18 nm, shifting to higher temperatures as film thickness is decreased. Notably, the onset thickness for the increase in Vogel temperature was lower in the NSE configuration compared to the CEC setup, attributed to the presence of the polymer-air interface.
KW - Thin polymer films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623422
DO - https://doi.org/10.1039/d4sm01238k
SN - 1744-6848
VL - 21
IS - 2
SP - 241
EP - 254
PB - RSC
AN - OPUS4-62342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, Q.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Yang, Z.
A1 - Wang, S.
A1 - Gao, Y.
A1 - Shang, J.
A1 - Hunger, J.
A1 - Aldiyarov, A.
A1 - Schönhals, Andreas
A1 - Ge, Y.
A1 - Qi, Z.
T1 - Molecular engineering of supramolecular polymer adhesive with confined water and a single crown ether
N2 - Here, we report a water-induced supramolecular polymer built from confined structural water and an intrinsic amphiphilic macrocyclic self-assembly in a nanophase separated structure. The newly designed crown ether macrocycle, featuring strong hydrophilic hydrogen bonding receptor selenoxide and a synergistical hydrophobic selenium-substituted crown core, confines the structural water in a segregated, interdigitated architecture. Although water molecules typically freeze around 0 °C, the confined structural water in this supramolecular polymer remains in a liquid-like state down to 80 °C. Previous studies suggest that multiple crown ether units are needed to generate structural water. However, here, one unit is sufficient to control the formation and disappearance of structural water and consequent supramolecular polymerization. Typically, the DC conductivity of water shows Arrhenius temperature dependency (lnσDC ∝ 1/T). In contrast, this new crown unit maintains water in confined states, which exhibit a Vogel/Fulcher/Tammann behavior (lnσDC ∝ 1/(T-T0)) at temperatures above the glass transition temperature. Moreover, this water-induced supramolecular polymer exhibits remarkable adhesion properties to hydrophilic surfaces and maintains tough adhesion at low temperatures. These findings show how a single small macrocycle can govern the complex structure and functionality of water in supramolecular systems.
KW - Supramolecular polymerization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623631
DO - https://doi.org/10.1039/D4SC06771A
SN - 2041-6539
VL - 16
SP - 1
EP - 9
PB - RSC
AN - OPUS4-62363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Haug, T. C. V.
A1 - Fröba, M.
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Molecular fluctuations in mixed-metal MOF-74: influence of the metal composition
N2 - A selected series of metal–organic frameworks M-MOF-74 (M = Mg, Co, Ni) and mixed metal MM-MOF-74 (Mg/Co or Mg/Ni) with different compositions of metal atoms have been prepared and further investigated by broadband dielectric spectroscopy (BDS) in a wide temperature range. The dielectric spectra show at least two relaxation processes. Process-A is observed only for the Ni-containing MOFs and is attributed to localized fluctuations of the metal oxide corners. Relaxation processes-B and -C are observed for all prepared MOFs, except that process-B is not observed for Ni-MOF-74. Large-angle fluctuations such as free rotations of the linkers can be excluded due to the structure of MOF-74, but small-angle fluctuations such as torsions are possible. According to numerical simulations carried out for MOF-74, process-B can be attributed to inward and outward fluctuations of the linkers relative to the pore center.
Process-C is related to small-angle rotational fluctuations of the linker together with co-rotations of the metal nodes. The latter interpretation is supported by the dependence of the activation energy of the relaxation rate of process-C on the metal composition of the MOFs, which is discussed in terms of the bond lengths between the metal atoms and the linker which decrease in the sequence Mg, Co and Ni.
KW - Metal Organic Frameworks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639378
DO - https://doi.org/10.1039/d5ra05357a
SN - 2046-2069
VL - 15
IS - 35
SP - 29109
EP - 29118
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
T1 - Investigations of Ultrathin Polymer Films Supported on Inorganic Substrates
N2 - Interactions between a polymer and a substrate interface play a vital role in understanding the improvement in thin film material properties as well as serving as a model for nanocomposites. For any non-repulsive polymer-substrate interactions, polymer segments form an irreversibly adsorbed layer and show a slowdown in the glassy dynamics and thus an increase in the thermal glass transition temperature compared to the bulk-like values. The growth kinetics of the adsorbed layer showed a deviation for both poly (bisphenol-A carbonate) (PBAC) and polysulfone (PSU), two bulky polymers containing a functional group (phenyl ring) in the backbone.
T2 - Royal Society of Chemistry (RSC) Online Poster Conference
CY - Online meeting
DA - 05.03.2024
KW - Adsorbed Layer
KW - Thin Films
KW - Atomic Force Microscopy
KW - Ellipsometry
PY - 2024
AN - OPUS4-59625
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Huang, J.
A1 - Mosane Razavi, Negar
A1 - Bojdys, M. J.
A1 - Forster, A. B.
A1 - Budd, P. M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Molecular Mobility and Gas Transport Properties of Mixed Matrix Membranes Based on PIM‑1 and a Phosphinine Containing Covalent Organic Framework
N2 - Polymers with intrinsic microporosity (PIMs) are gaining attention as gas separation membranes. Nevertheless, they face limitations due to pronounced physical aging. In this study a covalent organic framework containing λ5-phosphinine moieties, CPSF-EtO were incorporated as a nanofiller (concentration range 0-10 wt%) into a PIM-1 matrix forming dense films with a thickness of ca. 100 μm. The aim of the investigation was to investigate possible enhancements of gas transport properties and mitigating effects on physical aging. The incorporation of the nanofiller occurred on aggregate level with domains up to 100 nm as observed by T-SEM and confirmed by X-ray scattering. Moreover, the X-ray data show that the structure of the microporous network of the PIM-1 matrix is changed by the nanofiller.
As the molecular mobility is fundamental for gas transport as well as for physical aging, the study includes dielectric investigations of pure PIM-1 and PIM-1/CPSF-EtO mixed matrix membranes to establish a correlation between the molecular mobility and the gas transport properties. Using the time-lag method the gas permeability and the permselectivity were determined for N2, O2, CH4 and CO2 for samples with variation in filler content. A significant increase in the permeability of CH4 and CO2 (50 % increase compared to pure PIM-1) was observed for a concentration of 5 wt% of the nanofiller. Furthermore, the most pronounced change in the permselectivity was found for the gas pair CO2/N2 at a filler concentration of 7 wt%.
KW - Polymers of Intrinsic Microporosity
KW - Nanocomposites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595031
DO - https://doi.org/10.1021/acs.macromol.3c02419
SN - 0024-9297
VL - 57
IS - 4
SP - 1829
EP - 1845
PB - ACS Publications
AN - OPUS4-59503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Topolniak, Ievgeniia
A1 - Elert, Anna Maria
A1 - Knigge, Xenia
A1 - Ciftci, G. C.
A1 - Radnik, Jörg
A1 - Sturm, Heinz
T1 - High precision micropatterning of polydopamine by Multiphoton Lithography
N2 - Mussel-inspired polydopamine (PDA) initiated a multifunctional modification route that leads to the generation of novel advanced materials and their applications. However, existing PDA deposition techniques still exhibit poor spatial control, have a very limited capability of micropatterning and do not allow to locally tune PDA topography. Herein, we demonstrate PDA deposition based on Multiphoton Lithography (MPL) that enables full spatial and temporal control with nearly total freedom of patterning design. Using MPL, we achieve 2D microstructures of complex design with pattern precision of 0.8 μm without the need of a photomask or stamp. Moreover, this approach permits adjusting the morphology and thickness of the fabricated microstructure within one deposition step, resulting in a unique tunability of materials properties. The chemical composition of PDA is confirmed and its ability for protein enzyme immobilization is demonstrated. This work presents a new methodology for high precision and complete control of PDA deposition, enabling PDA incorporation in applications where fine and precise local surface functionalization is required. Possible applications include multicomponent functional elements and devices in microfluidics or lab-on-a-chip systems.
KW - Multiphoton lithography
KW - Polydopamine
KW - Micropatterning
PY - 2022
DO - https://doi.org/10.1002/adma.202109509
VL - 34
IS - 18
SP - e2109509
PB - Wiley online library
AN - OPUS4-54535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waniek, Tassilo
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
T1 - The influence of water released from particles in epoxy‐based nanocomposites
N2 - AbstractRecent studies have hypothesized that the reinforcing effects of boehmite nanoparticles (BNPs) in polymer nanocomposites (PNCs) are partly related to the particles themselves and partly to the water released from the BNP during curing. In this work, PNCs made from dried BNP (dBNP) with concentrations up to 15 wt% are investigated to differentiate particle and water related effects. The observed trend of the storage modulus in dynamic mechanical thermal analysis measurements was found to be independent of the drying procedure. Stiffness maps from intermodulation atomic force microscopy showed that dBNP leads to a stiffening of the interphase surrounding the particles compared with the unaffected epoxy matrix, while a softer interphase was reported for PNCs with as received BNP. A slight decrease in the glass transition temperature was observed by broadband dielectric spectroscopy related to a lowered crosslink density due to the particles. A significantly higher decrease was reported for PNCs with BNP, attributed to water influencing the curing process. In conclusion, the stiffening of PNC with BNP is related to the particles themselves, while the release of water causes the formation of a soft interphase in the vicinity of the particles and a significant decrease in crosslink density.
KW - AFM stiffness of interface
KW - Aluminium oxide hydroxide
KW - Boehmit nanoparticle
KW - Glass transition temperature
KW - Broadband dielectric spectroscopy
KW - Crosslink density control
KW - Structure–property relationship
KW - Nanocomposites
KW - Thermoset
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606772
DO - https://doi.org/10.1002/app.55937
SN - 0021-8995
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-60677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed A.
A1 - Zhuoqing, L.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Wuckert, E.
A1 - Raab, A.
A1 - Laschat, S.
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Confinement-suppressed phase transition and dynamic self-assembly of ionic superdiscs in ordered nanochannels: Implication for nanoscale applications
N2 - Ionic Liquid Crystals are ionic liquids that exhibit liquid crystalline mesomorphism together with ionic conductivity. As known confined liquid crystal mesophases can show an anomalous dynamics and phase behavior. Investigations considering the factors controlling the macroscopic properties of ILCs in confinement are scare in the literature. This study reports the molecular mobility, and the phase transition behavior of a guanidinium based columnar ILC confined in the nanopores of self-ordered anodic aluminum oxide membranes of various pore diameters (25 – 180 nm) using Broadband Dielectric Spectroscopy (BDS), calorimetry and X-ray scattering. It is aimed to reveal in which way the pore size as well as the pore surface wettability (hydrophobic or hydrophilic) alters the molecular dynamics, and phase transition behavior for this system. These properties are crucial for applications. The DSC investigations reveal: (i) the phase transition temperature for the transition from the plastic crystalline to the crystalline-liquid state has non-monotonic dependence versus the inverse pore diameter and (ii) the transition from the liquid crystalline to the isotropic phase is suppressed for all nanoconfined samples. This transition suppressed in the thermal signal was evidenced by BDS and X-ray scattering. It is discussed as a continuous phase transition taking place in the pores instead of a discontinuous first order transition as observed for the bulk. BDS investigations show different relaxation processes for the bulk and the nanoconfined ILC. Molecular origins for various relaxation processes are discussed and suggested. It is further shown that the self-assembly of this ILC is dynamic in nature which might apply for other ILCs too. The obtained results will have implications for the nanoscale applications of ionic liquid crystals.
KW - Ionic Liquid Crystals
PY - 2023
DO - https://doi.org/10.1021/acsanm.3c02473
VL - 6
IS - 17
SP - 15673
EP - 15684
PB - ACS
AN - OPUS4-58210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Juranyi, Fanni
A1 - Böhning, Martin
A1 - Zorn, Reiner
A1 - Schönhals, Andreas
T1 - Low-Frequency Vibrational Density of State of Janus-Polynorbornenes: The Dependence of the Boson Peak on the Nanophase-Separated Structure
N2 - Inelastic incoherent neutron time-of-flight scattering was employed to investigate the low-frequency vibrational density of states (VDOSs) for a series of glassy Janus-poly(tricyclononenes), which consist of a rigid main chain and flexible alkyl side chains. Here, the length of the flexible side chains was systematically varied from propyl to octyl. Such materials have potential applications as active separation layers in gas separation membranes as a green future technology, especially for the separation of higher hydrocarbons. From the morphological point of view, the Janus polynorbornenes undergo a nanophase separation into alkyl side chain-rich nanodomains surrounded by a rigid polynorbornene matrix. Here, the influence of the nanophase-separated structure on the low-frequency VDOS is investigated from a fundamental point of view. The low-frequency VDOSs of these Janus polynorbornene show excess contributions to the Debye type VDOS known as the Boson peak (BP) for all side chain lengths. Due to the high incoherent scattering cross-section of hydrogen, most of the scattering comes from the alkyl side chain-rich domains.
Compared to conventional glass-forming materials, in the considered Janus polynorbornenes, the BP has a much lower intensity and its frequency position is shifted to higher values. These experimental results are discussed in terms of the nanophase-separated structure where the alkyl chain-rich domains were constrained by the surrounding matrix dominated by the rigid backbone. With increasing alkyl chain length, the size of the alkyl chain-rich domains increases. The frequency position of the BP shifts linearly to lower frequencies with the size of these nanodomains estimated from X-ray measurements. The obtained results support the sound wave interpretation to the BP
KW - Inelastic neutron scattering
PY - 2023
DO - https://doi.org/10.1021/acs.macromol.3c00913
SN - 0024-9297
SP - 1
EP - 10
PB - ACS
AN - OPUS4-57972
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emamverdi, Farnaz
T1 - Molecular Mobility and Physical Aging of Polymers with Intrinsic Microporosity (PIM-1) Revisited: A Big Glassy World
N2 - Polymeric membranes represent a cost- and energy-efficient solution for gas separation. Recently Polymers of Intrinsic Microporosity (PIMs) have been in a great interest because of their outstanding BET surface area larger than 700m2/g and pore size smaller than 1 nm. PIMs are a promising candidate in gas separation with high permeability and appealing selectivity due to their inefficient packing derived from a combination of ladder-like rigid segments with sites of contortion. However, it is recognized this class of polymers suffer from decrease in performance with time due to physical aging. The initial microporous structures approach a denser state via local chain rearrangements, leading to a dramatic reduction in permeability. As chain packing during film casting and physical aging are the key factors determine the performance in separation applications, characterization of the molecular mobility in these materials has been proved to provide valuable information. In recent research on PIM-1 the archetypal PIM, a molecular relaxation process with high activation energy together with a significant conductivity in the glassy state has been found and explained with the formation of local intermolecular agglomerates due to interaction of π-electrons in aromatic moieties of the polymer backbone. In this work, the dielectric behavior of the polymeric films and their response upon heating (aging) were measured by isothermal frequency scans during different heating/cooling cycles in a broad temperature range down to 133K for the first time. Multiple dielectric processes following Arrhenius behavior were observed. Local fluctuations, Maxwell-Wagner-Sillars (MWS) polarization and structural relaxations were discussed correlating to structural-properties of PIM-1. Up to now, no other work has studied the role of porosity and thermal history of PIM-1 film in dielectric processes. The goal is by eliminating thermal history and considering storing conditions provide better understanding on aging and plasticizing in high free volume glassy polymer PIM-1.
T2 - Euromembrane conference
CY - Copenhagen, Denmark
DA - 29.11.2021
KW - Physical aging
KW - Membrane
KW - Microporous structure
KW - Glassy polymer
PY - 2021
AN - OPUS4-55758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Physical investigations on Super glassy Polymers having possible applications in gas Separation Membranes
N2 - The properties of polymers of intrinsic microporosity were investigated by fast scanning calorimetry, dielectric spectroscopy and neutron scattering
T2 - University of Pennsylvania
CY - Online meeting
DA - 25.01.2021
KW - Polymer of intrisic microporosity
PY - 2021
AN - OPUS4-52065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Thermal behavior of high preformance polymers - Fast Scanning Calorimetry and more
N2 - The glass tranistion behavior of polymers of intrinsic microporosity and polynornornes is discussed.
T2 - Flash DSC Conference 2021
CY - Online meeting
DA - 06.12.2021
KW - Polymer of Intrisic Maicroporosity
KW - Highly permeable polynorbornenes
PY - 2021
AN - OPUS4-53938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
T1 - Growth Kinetics and Molecular Mobility of the adsorbed Layer of Poly(bisphenol-A Carbonate) (PBAC), Polysulfone (PSU), and Poly (2-Vinyl Pyridine) (P2VP)
N2 - Interactions between a polymer and a substrate interface play a vital role in understanding the improvement in thin film material properties as well as serving as a model for nanocomposites. For any non-repulsive polymer-substrate interactions, polymer segments form an irreversibly adsorbed layer and show a slowdown in the glassy dynamics and thus an increase in the thermal glass transition temperature compared to the bulk-like values. The growth kinetics of the adsorbed layer obey a two-step mechanism: formation of immobilized layer with flat segmental conformations and a loosely bound layer with stretched chains pinned to the surface. Here the adsorbed layer was studied for: poly (bisphenol-A carbonate) (PBAC) and polysulfone (PSU), two bulky polymers containing a functional group (phenyl ring) in the backbone and compared to poly (2-vinyl pyridine) (P2VP), where the backbone is a vinyl-derivative and the functional group (pyridine) is in the side chain. The growth kinetics for PBAC and PSU were found to deviate from the well-known mechanism, observed for polymers such as P2VP. Atomic force microscopy and ellipsometry were used for this investigation and was additionally supported by broadband dielectric spectroscopy.
T2 - Deutschen Physikalische Gesellschaft (DPG) Tagung
CY - Dresden, Germany
DA - 26.03.2023
KW - Thin films
KW - Adsorbed Layer
KW - Broadband dielectric spectroscopy
KW - Atomic force microscopy
KW - Growth Kinetics
PY - 2023
AN - OPUS4-57282
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winckelmann, Alexander
T1 - Next level lithium isotope analysis by atomic absorption spectrometry in combination with machine learning
N2 - An alternative method for lithium isotope amount ratio analysis is proposed by combining atomic absorption spectrometry with spectra data analysis by machine leaning. It is based on the well-known isotope shift of around 15 pm for the electronic transition at wavelength 670.7845 nm which can be measured by a high-resolution continuum source atomic absorption spectrometer (HR-CS-AAS). For isotope amount ratio analysis, a scalable three boosting machine learning algorithm (XGBoost) was employed and calibrated with a set of samples with a 6Li isotope amount fraction ranging from 99% to 6%. The absolute Li isotope amount fractions of these calibration samples were previously measured by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) and used as ab-initio data for the machine learning algorithm. Validation of the machine leaning model was performed with two standard reference materials (LSVEC and IRMM-016). The procedure was employed for the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, LiOH, and LiF) as well as a BAM candidate LiMNC cathode reference material. Achieved uncertainties are one order of magnitude higher than those obtained by MC-ICP-MS. This precision and accuracy is nonetheless sufficient to resolve natural occurring variations in Lithium isotope ratios. Also, the LiMNC material was analyzed by HR-CS-AAS with and without matrix purification. The results are comparable within statistical error.
T2 - Make and Measure 2020
CY - Online Meeting
DA - 15.10.2020
KW - Lithium batteries
KW - HR-CS-AAS
KW - Machine learning
KW - Isotope analysis
KW - Spectrometry
PY - 2020
AN - OPUS4-51541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Friedrich, J.
T1 - Structure of plasma deposited acrylic acid‐allyl alcohol copolymers
N2 - Copolymer thin films with two types of functional groups have excellent performance as sensors, for example. The formation and deposition of allyl alcohol‐acrylic acid copolymer films by pulsed high frequency plasma is a complex process. As usual, the chemical composition of the top surface of the films was investigated by XPS and FTIR measurements. Furthermore, contact angle measurements with water were used to characterise the hydrophilicity and wettability of the polymer films.
After plasma deposition, a significant decrease in functional groups (OH and COOH) was observed compared to the classically copolymerised equivalent.
The remaining functional groups, i.e. the majority of these groups, were sufficient for application as sensor layers. Segmental mobility and conductivity, important for sensor applications, were analysed by broadband dielectric spectroscopy.
KW - Plasma Polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578349
DO - https://doi.org/10.1002/ppap.202300071
SN - 1612-8850
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-57834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abdel-Wakil, W.
A1 - Fahmy, Alaa
A1 - Kamoun, E.
A1 - Hassan, W.
A1 - Abdelhai, Q.
A1 - Salama, T.
T1 - A New Route for Synthesis of Polyurethanevinyl Acetate Acrylate Emulsions as Binders for Pigment Printing of Cotton Fabrics
N2 - Herein, two polyurethane oligomers were successfully synthesized using a prepolymer mixing process. The prepolymers were synthesized based on the step-growth addition polymerization of polypropylene glycol, Methylene diphenyl diisocyanate and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was functioned as the isocyanate blocking agent. Thereafter, different terpolymer emulsions were prepared by the emulsion graft copolymerization with the vinyl acetate monomer in presence of 2-ethylhexyl acrylate as a vinyl monomer. The chemical structures of the synthesized oligomeric monomers were probed by FTIR spectroscopy and found to vary with the content of acrylic monomer used in the oligomer synthesis phase (i.e.hydroxyethyl acrylate or hydroxyethyl methacrylate). The topography, thermal stability, and particle size of terpolymers were investigated by SEM, TGA, and zeta potential, respectively. The TGA results demonstrated marked enhancement in thermal stability of the synthesized terpolymers up to ca. 600°C, which was concurrent with enhanced surface homogeneity and film properties as evidenced by the SEM images. These terpolymers showed also property enhancement as binders for textile pigment printing in terms of rubbing resistance, color strength and fastness to washing when compared to the commercial binders.
These judgments would provide a new competent synthesis route by introducing polyurethane acetate vinyl acrylate as the binder for use in pigment printing of cotton fabrics.
KW - Vinyl monomer
KW - Polyurethane acetate vinyl acrylate
KW - Surface coating
KW - Terpolymer
KW - Textile binder
PY - 2020
DO - https://doi.org/10.21608/ejchem.2020.21712.2292
VL - 63
IS - 3
SP - 1063
EP - 1073
AN - OPUS4-52300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
T1 - DICONDE für die Schienenprüfung
N2 - Bei der zerstörungsfreien Prüfung verlegter Eisenbahnschienen werden die Rohdaten derzeit in proprietären Datenformaten gespeichert und auf Datenträgern zwischen den Prüfzügen und den auswertenden Stellen versendet. Die proprietären Datenformate sind in der Regel nur den Herstellern der Prüfsysteme bekannt und deren Dokumentation nicht allgemein zugänglich.
Das Forschungsprojekt „Artificial Intelligence for Rail Inspection“ (AIFRI) erfordert den Austausch von Prüfdaten in einem offenen Format sowohl zwischen den Projektpartnern als auch die Veröffentlichung anonymisierter Daten ausgewählter Strecken aus dem Offenen Digitalen Testfeld (ODT). Wir haben uns in dem Projekt für die Verwendung der „Standard Practice for Digital Imaging and Communication in Nondestructive Evaluation“ (DICONDE) entschieden. DICONDE basiert auf dem medizinischen Standard „Digital Imaging and Communication in Medicine“ (DICOM) und wurde von ASTM an die ZfP angepasst. DICOM bzw. DICONDE ist nicht nur ein Datenformat, sondern beinhaltet auch Kommunikationsschnittstellen für die Auftragsvergabe, Datenübertragung und Abfrage gespeicherter Datensätze aus einem Archiv.
In dem Vortrag werden DICOM und DICONDE vorgestellt, sowie die Verwendung von DICONDE für die Schienenprüfung im Projekt AIFRI näher erläutert. Es wird gezeigt, wie sich Prüfdaten, Prüfparameter, Streckeninformationen incl. Kilometertafeln und Geokoordinaten und Befunde in DICONDE kodieren lassen.
T2 - 13. Fachtagung ZfP im Eisenbahnwesen
CY - Erfurt, Germany
DA - 12.03.2024
KW - DICONDE
KW - Wirbelstromprüfung
KW - Ultraschallprüfung
KW - Schienenprüfung
PY - 2024
AN - OPUS4-59663
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Kolmangadi, Mohamed Aejaz
A1 - Schönhals, Andreas
A1 - Friedrich, J.
T1 - Structure of plasma‐deposited copolymer films preparedfrom acrylic acid and styrene: Part III sulfonation andelectrochemical properties
N2 - Acrylic acid-styrene copolymer films were deposited plasma-chemically more gently using the pulsed plasma mode instead of the continuous mode, with linear and some slightly branched chains and marginal crosslinking.
Then, the styrene unit of copolymers was wet-chemically sulfonated by chlorosulfuric acid. On exposure to air, the formed 4-chlorosulfonic acid groups hydrolyze to sulfonic acid groups (-SO3H).
FTIR, XPS and broadband dielectric spectroscopy were employed to characterize the composition, the structure, the functional groups, and the electrochemical performance for the copolymers. A high concentration of sulfonic acid-containing groups was obtained in the sulfonated PS sample. The values of the DC conductivity DC for the sulfonated sample of the AA/S copolymer are ca. five orders of magnitude higher than that of the not-sulfonated copolymer materials.
KW - Plasma Polymers
KW - Electrolyte membrane
PY - 2022
DO - https://doi.org/10.1002/ppap.202100222
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-54539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - NeXus at the core of the HExX-lab
N2 - Through bottom-up, comprehensive digitalisation of all aspects of an experiment, the HEX-lab improves the trustworthiness (traceability, reproducibility, quality) of scientific findings.
The five main parts that make up a materials science experiment, i.e. Sample preparation, Measurements, Processing, Analysis, and Interpretation, each have been addressed in thorough and unique ways in this lab, building up a foundation for a wide range of materials science collaborations. Improvements span the spectrum.
Hardware developments include new sample environments and stages, such as grazing incidence motion towers, electrochemistry cells and flow-through holders, electronic components such as safety interlocks and multipurpose I/O controllers, and liquid handling systems such as coolant flow cross-over systems.
Software developments include:
1) a new comprehensive control system operating on both the RoWaN as well as the MOUSE allowing for full Python control and sequencing of all experimentation,
2) Automated scripts for instrument optimization, sample alignments and measurements,
3) revamped data pipelines and analysis software, standalone or launched as part of operations sequencing dashboards on servers, and
4) meticulously structured archival datafiles, fully documenting sample preparation, measurements, processing and analyses. These allow for holistic databases and dashboards to be constructed to investigate the links between synthesis parameters and resulting morphology.
This presentation will highlight some of the tools and techniques developed and available in the HEX-lab over the years, from sample environments to overarching experiment and data organisation structures.
T2 - Materials Science Core Facility Synergy Forum 2025
CY - Bremen, Germany
DA - 26.02.2025
KW - Digitalization
KW - Automation
KW - HDF5
KW - Traceability
KW - Data stewardship
KW - Lab automation
KW - Holistic science
KW - Methodology
PY - 2025
AN - OPUS4-62676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bresch, Harald
T1 - Nano and Advanced Materials - Competences at BAM and perspectives
N2 - This presentation gives an overview about the competencies and the characterization possibilities of nanoparticles at BAT, based on this the development of the OECD TG 125 at BAM. It further describes research activities at BAM concerning the characterization of nanoparticles and the way to the digital representation of these characterization possibilities. It concludes with the challenges of a digital product passport (DPP) for nanomaterial based products and the need of a digital materials passport (DMP). Finally, the activities of BAM are presented which address the former mentioned challenges from ESRP and DPP.
T2 - Austausch Helmholtz Hereon / Digipass & BAM
CY - Berlin, Germany
DA - 07.07.2025
KW - Nanomaterials
KW - ESPR
KW - DPP
KW - Nano
KW - Advanced Materials
PY - 2025
AN - OPUS4-64974
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - DACHS/MOFs/AutoMOFs_3/Synthesis
N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters.
DACHS_MOFs is simultaneously used to test the DACHS principles.
This upload contain synthesis data from AutoMOFs_3 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample.
KW - Synthesis
KW - Automation
KW - Traceability
KW - Procedure
PY - 2024
DO - https://doi.org/10.5281/zenodo.11237815
PB - Zenodo
CY - Geneva
AN - OPUS4-60633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Scoppola, E.
A1 - Jha, D.
A1 - Morales, L. F. G.
A1 - Moya, A.
A1 - Wirth, R.
A1 - Pauw, Brian Richard
A1 - Emmerling, Franziska
A1 - Van Driessche, A. E. S.
T1 - Seeds of imperfection rule the mesocrystalline disorder in natural anhydrite single crystals
N2 - In recent years, we have come to appreciate the astounding intricacies associated with the formation of minerals from ions in aqueous solutions. In this context, a number of studies have revealed that the nucleation of calcium sulfate systems occurs nonclassically, involving the aggregation and reorganization of nanosized prenucleation species. In recent work, we have shown that this particle-mediated nucleation pathway is actually imprinted in the resultant micrometer-sized CaSO4 crystals. This property of CaSO4 minerals provides us with the unique opportunity to search for evidence of nonclassical nucleation pathways in geological environments.
In particular, we focused on large anhydrite Crystals extracted from the Naica Mine in Mexico. We were able to shed light on this mineral's growth history by mapping defects at different length scales. Based on this, we argue that the nanoscale misalignment of the structural subunits, observed in the initial calcium sulfate crystal seeds, propagates through different length scales both in morphological, as well as in strictly crystallographic aspects, eventually causing the formation of large mesostructured single crystals of anhydrite. Hence, the nonclassical nucleation mechanism introduces a “seed of imperfection,” which leads to a macroscopic “single” crystal whose fragments do not fit together at different length scales in a self-similar manner. Consequently, anisotropic voids of various sizes are formed with very welldefined walls/edges. However, at the same time, the material retains in part its single crystal nature.
KW - Calcium sulfate
KW - Anhydrite
KW - Mesocrystal
KW - Nucleation
KW - Naica
PY - 2021
DO - https://doi.org/10.1073/pnas.2111213118
SN - 0027-8424
VL - 118
IS - 48
SP - 1
EP - 11
PB - National Academy of Sciences (USA)
CY - Washington
AN - OPUS4-53820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Wimmer, Lukas
A1 - Alcolea-Rodriguez, Victor
A1 - Waniek, Tassilo
A1 - Wachtendorf, Volker
A1 - Matzdorf, Kay
A1 - Ciornii, Dmitri
A1 - Fengler, Petra
A1 - Milczewski, Frank
A1 - Otazo-Aseguinolaza, Itziar
A1 - Ferrer, Manuel
A1 - Bañares, Miguel A.
A1 - Portela, Raquel
A1 - Dailey, Lea Ann
T1 - Quality-by-design and current good practices for the production of test and reference materials for micro- and nano-plastic research
N2 - Understanding the environmental and human health impacts of micro- and nanoplastic pollutants is currently a high priority, stimulating intensive methodological research work in the areas of sampling, sample preparation and detection as well as intensive monitoring and testing. It is challenging to identify and quantify microplastics in complex organic matrices and concepts for nanoplastic detection are still in their infancy. All analytical techniques employed in studying micro- and nanoplastics require suitable reference materials for validation measurements, with requirements as diverse as the analytical tools used, ranging from different polymer types, size distributions and shapes of the material to the concentrations employed in different experimental set ups (ng to g amounts). The aim of this manuscript is to outline current good practices for small-scale laboratory production and characterization of suitable test and reference materials. The focus is placed on top-downfragmentation methods as well as bottom-up precipitation methods. Examples using polyethylene, polypropylene, polystyrene and polyethylene terephthalate with size distribution classes of mainly 10–1000, 1–10 and <1 μm particles will be provided. Experiences and suggestions on how to produce well-characterized micro- and nano-plastics for internal research needs will ensure that studies using the materials have robust and informative outcomes.
KW - Mmicroplastics
KW - Nanoplastics
KW - Reference materials
KW - Standard validation method
PY - 2025
DO - https://doi.org/10.1016/j.jhazmat.2025.139595
SN - 0304-3894
VL - 497
SP - 1
EP - 20
PB - Elsevier B.V.
AN - OPUS4-63958
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wiesner, Yosri
T1 - Reference material candidates for Microplastic analysis
N2 - Microplastic reference material is required for validation and harmonization purposes. This includes the analysis of the pure polymer particles and the validation of the respective measurement methods. In addition, there is the harmonization of different laboratories. On the other hand, sample preparation methods must be validated and harmonized with regard to their recovery and subsequent analysis in the respective matrices. For this purpose, we produce reference material candidates in the form of tablets with different mass fractions and particle numbers of polyethelene terephthalate. In the presentation first measurement results by µ-Raman, µ-FTIR, pyrolysis-GC-MS and TED-GC/MS will be presented.
T2 - SETAC Europe 34th Annual Meeting
CY - Seville, Spain
DA - 05.05.2024
KW - Reference material
KW - Microplastics
KW - PlasticTrace
PY - 2024
AN - OPUS4-60019
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - May, Anastasia
T1 - Pyrazinamide-Pimelic Acid Cocrystals: A Mechanochemical and Thermal Study
N2 - Cocrystals represent a promising class of crystalline materials, offering a wide potential for physico-chemical property alteration of chemical compounds, such as their solubility, by cocrystallizing the targeted compound with another solid material. In the present study, we investigated the cocrystal system between the anti-tuberculosis drug pyrazinamide (PZA) and pimelic acid (PA) by thermal characterization and milling conditions of mechanochemical synthesis. Thermal treatment resulted in the formation of a eutectic between the compounds PZA and PA. Furthermore, irreversible separation of the cocrystal occurred upon melting. This finding indicated low stability of the cocrystal and the necessity of mechanochemical synthesis for cocrystal formation. The mechanochemical synthesis parameters were elucidated by investigating the temperature effect while milling and the role of pre-milling the coformer PA using in-situ monitoring techniques. The polymorphism of PA, influenced by temperature and pre-milling, exhibited a substantial impact on the kinetics of cocrystallization. This finding underscores the significance of coformer polymorphism as an additional factor in mechanochemical cocrystallization reactions.
T2 - 11th International Conference on Mechanochemistry and Mechanical Alloying
CY - Berlin, Germany
DA - 14.09.2025
KW - Cocrystal
PY - 2025
AN - OPUS4-65353
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martins, I.
A1 - Carta, M.
A1 - Haferkamp, Sebastian
A1 - Feiler, Torvid
A1 - Delogu, F.
A1 - Colacino, E.
A1 - Emmerling, Franziska
T1 - Mechanochemical N‑Chlorination Reaction of Hydantoin: In Situ Real-Time Kinetic Study by Powder X‑ray Diffraction and Raman Spectroscopy
N2 - Mechanochemistry has become a valuable tool for the synthesis of new molecules, especially in the field of organic chemistry. In the present work, we investigate the kinetic profile of the chlorination reaction of N-3-ethyl-5,5-dimethylhydantoin (EDMH) activated and driven by ball milling. The reaction has been carried out using 2 mm, 4 mm, 5 mm, 6 mm, and 8 mm ball sizes in a new small custom-made Perspex milling jar. The Crystal structure of the starting material EDMH and the 1-chloro-3-ethyl5,5′-dimethyl hydantoin (CEDMH) chlorination product was solved by single-crystal X-ray diffraction. The reaction was monitored, in situ and in real time, by both powder X-ray diffraction (PXRD) and Raman spectroscopy. Our kinetic data show that the reaction progress to equilibrium is similar at all milling ball sizes. The induction period is very short (between 10 and 40 s) when using 4 mm, 5 mm, 6 mm, and 8 mm balls. For the reaction performed with a 2 mm ball, a significantly longer induction period of 9 min was observed. This could indicate that an initial energy accumulation and higher mixing efficiency are necessary before the reaction starts. Using different kinetic models, we found that the amount of powder affected by critical loading conditions during individual impacts is significantly dependent on the ball size used. An almost linear correlation between the rate of the chemical transformations and the ball volume is observed.
KW - Mechanochemistry
KW - In situ real-time monitoring
KW - N-Chlorination
KW - Kinetics
KW - Hydantoin
KW - Powder X-ray diffraction
KW - Raman spectroscopy
PY - 2021
DO - https://doi.org/10.1021/acssuschemeng.1c03812
VL - 9
IS - 37
SP - 12591
EP - 12601
AN - OPUS4-53541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Souza, B.
A1 - Chauque, S.
A1 - de Oliveira, P.
A1 - Emmerling, Franziska
A1 - Torresi, R.
T1 - Mechanochemical optimization of ZIF-8/Carbon/S8 composites for lithium-sulfur batteries positive electrodes
N2 - The application of lithium-sulfur (Li-S) batteries is still limited by their rapid capacity fading. The pulverization of the sulfur positive electrode after the lithiation and the consequence dissolution of long chain polysulfides in organic solvents lead to the shuttle effect. To address these issues, here we report the mechanochemical preparation of ZIF-8 (Zeolitic Imidazole Framework-8)-based composites as sulfur hosts for positive electrodes in Li-S batteries. We studied different methods for the incorporation of conductive carbon. Also, the replacement of Zn2+ metal centers by other bivalent metals (Cu2+, Co2+ and Ni2+), enabled the preparation of other ZIF-8-based materials. The positive electrode ZIF-8/C/S8 showed initial discharges of 772 mA h g−1 while the pristine one, ZIF-8/S8, displayed 502 mA h g−1. The enhanced performance of 54% for ZIF-8/C/S8 indicates that the direct mechanochemical synthesis of ZIF-8 with conductive carbon is beneficial at initials charge/discharge process in comparison to traditional slurry preparation (ZIF-8/S8). Also, the Li2S6 absorption tests shows 87% of discoloration with ZIF-8/C/S8, confirming the better polysulfides absorption.
KW - Lithium-sulfur battery
KW - Metal organic frameworks
KW - ZIF-8
KW - Mechanochemistry
PY - 2021
DO - https://doi.org/10.1016/j.jelechem.2021.115459
VL - 896
SP - 115459
PB - Elsevier B.V.
AN - OPUS4-53542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stawski, Tomasz
T1 - Seeds of imperfection rule the mesocrystalline disorder in natural anhydrite single crystals
N2 - In recent years, we have come to appreciate the astounding intricacy of the formation process of minerals from ions in aqueous solutions. In this context, a number of studies have revealed that nucleation in the calcium sulfate system is non-classical, involving the aggregation and reorganization of nanosized prenucleation particles. In a recent work we have shown that this particle-mediated nucleation pathway is actually imprinted in the resultant single micron-sized CaSO4 crystals. This property of CaSO4 minerals provides us with an unique opportunity to search for evidence of non-classical nucleation pathways in geological environments. In particular, we focused on the quintessential single crystals of anhydrite extracted from the Naica mine in Mexico. We elucidated the growth history from this mineral sample by mapping growth defects at different length scales. Based on these data we argue that the nano-scale misalignment of the structural sub-units observed in the initial calcium sulfate crystal seed propagate through different length-scales both in morphological, as well as strictly crystallographic aspects, eventually causing the formation of large mesostructured single crystals of anhydrite. Hence, the nanoparticle mediated nucleation mechanism introduces a 'seed of imperfection', which leads to a macroscopic single crystal, in which its fragments do not fit together at different length-scales in a self-similar manner. Consequently, anisotropic voids of various sizes are formed with very well-defined walls/edges. But, at the same time the material retains its essential single crystal nature. These findings shed new light on the longstanding concept of crystal structure.
T2 - S4SAS Conference 2021
CY - Online meeting
DA - 01.09.2021
KW - SAXS
KW - Calcium sulfate
KW - Anhydrite
KW - Mesocrystals
PY - 2021
AN - OPUS4-53630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - Fluorine Modified ZIF 8 for Electrochemical Catalysis: Where does the Fluorine go?
N2 - Carbonization of fluorinated metal-organic frameworks (MOFs) should yield fluorinated nitrogen- and metal-doped carbons (F-NMCs), which are a combination of NMCs and fluorinated carbons, each promising electrocatalysts on their own. We synthesized two polymorphs of a fluorinated MOF by mechanical ball mill grinding, and carbonized them to yield potential electrocatalyt materials. The catalytical activity towards the oxygen reduction reaction (ORR) was examined, finding good activites. Simulations from a theoretic model helped assesing the stability of proposed catalytic sites and understanding the measured activites towards the ORR catalysis.
T2 - Online symposium of the CRC 1349 "fluorine-specific interactions"
CY - Online meeting
DA - 29.06.2021
KW - PGM-free catalyst
KW - Oxygen Reduction Reaction
KW - Mechanochemistry
KW - MOFs
KW - Computational chemistry
PY - 2021
AN - OPUS4-53538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - Synthesis and characterization of fluorinated Co-Zn-Zeolitic imidazole frameworks for catalysis of the oxygen reduction reaction
N2 - The oxygen reduction reaction (ORR) is a common process in a variety of electrochemical devices, like fuel cells
and metal air batteries. The sluggish kinetics of the ORR require an electrocatalyst to pass this bottleneck.[1]
Currently, the most used catalytical systems are platinum-based, with several drawbacks, such as the high cost,
low availability, and deactivation by CO poisoning.[2] Efforts are made to develop efficient, durable and low cost
catalysts to promote the commercialization of fuel cells.
Non-precious metal catalysts are promising candidates for efficient ORR catalysis. It has been shown that
pyrolyzing metal organic frameworks (MOFs) under inert conditions yields carbon-rich materials, with evenly
distributed metal sites, which possess promising electrocatalytic activity.[3] One widely used type of MOF as ORR
catalyst precursors is the zeolitic imidazole framework (ZIF) where metal cations are linked through imidazolebased ligands.
Herein we report the mechanochemical synthesis, structural analysis and of Co-doped ZIF-8 (Zn), as well as its
fluorinated counterpart Co-doped CF3
-ZIF-8 (Zn). The samples showed electrochemical performance comparable
to platinum after carbonization for 1h at temperatures ranging between 850 – 1000°C.
T2 - 15th International conference on materials chemistry (MC15)
CY - Online meeting
DA - 12.07.2021
KW - PGM-free catalyst
KW - Oxygen Reduction Reaction
KW - Mechanochemistry
KW - MOFs
PY - 2021
AN - OPUS4-53539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - The Effect of Fluorine on Catalysts for the Oxygen Reduction Reaction obtained from Metal Organic Frameworks
N2 - The oxygen reduction reaction (ORR) – an important reaction in electrochemical devices, such as fuel cells - is characterized by its sluggish kinetics and therefore requires catalysis. The industry currently relies on platinum as a catalyst, although it is scarce and expensive, hindering the commercial breakthrough of fuel cells in automotive applications. Platinum-free catalysts on basis of nitrogen- and metal doped carbons (NMCs) and fluorinated carbons are promising materials to replace platinum-based catalysts for the ORR. In this work we prepared six metal-organic frameworks (MOFs) by mechanical ball mill grinding and studied their formation by in-situ powder X-ray diffraction. Furthermore, the samples were carbonized under controlled conditions (900°C, 1h, N2-atmosphere) to yield carbon materials, that were employed in ORR-electrocatalysis. The effect of Co-doping and fluorination was systematically studied and outstanding ORR activity was found for the catalyst prepared from the Co-doped fluorinated ZIF-8.
T2 - International Symposium on Fluorine-specific interactions
CY - Berlin, Germany
DA - 27.09.2021
KW - PGM-free catalyst
KW - Oxygen Reduction Reaction
KW - Mechanochemistry
KW - MOFs
PY - 2021
AN - OPUS4-53533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rautenberg, Max
T1 - Fluorination and co-doping of ZIF-8 by ball mill grinding for efficient oxygen reduction electrocatalysis
N2 - The oxygen reduction reaction (ORR) is a common process in a variety of electrochemical devices, like fuel cells and metal air batteries. The sluggish kinetics of the ORR require an electrocatalyst to pass this bottleneck.[1] Currently, the most used catalytical systems are platinum-based, with several drawbacks, such as the high cost, low availability, and deactivation by CO poisoning.[2] Efforts are made to develop efficient, durable and low cost catalysts to promote the commercialization of fuel cells.
Non-precious metal catalysts are promising candidates for efficient ORR catalysis. It has been shown that pyrolyzing metal organic frameworks (MOFs) under inert conditions yields carbon-rich materials, with evenly distributed metal sites, which possess promising electrocatalytic activity.[3] One widely used type of MOF as ORR catalyst precursors is the zeolitic imidazole framework (ZIF) where metal cations are linked through imidazole-based ligands. Their porous nature is partially retained after carbonization, making MOFs very suitable precursor materials.
Herein we report the mechanochemical synthesis and structural analysis of Co-doped ZIF-8 (Zn), as well as two polymorphs (dense and prorous) of fluorinated Co-doped CF3-ZIF-8 (Zn). The samples showed electrochemical performance comparable to platinum after carbonization for 1 h at temperatures ranging between 850 – 1000°C.
T2 - XXV General Assembly and Congress of the International Union of Crystallography - IUCr 2021
CY - Prague, Czech Republic
DA - 14.08.2021
KW - PGM-free catalyst
KW - Oxygen Reduction Reaction
KW - Mechanochemistry
KW - MOFs
PY - 2021
AN - OPUS4-53535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Linberg, Kevin
T1 - Tipping the Energy Scales to Control Mechanochemical Polymorphism
N2 - Control of ball milling conversions is required before the full potential of mechanochemical processing can be realized. It is well known that many parameters affect the outcome of mechanochemical polymorphism, but the energy of ball milling itself is often overlooked. We show here how this parameter alone can exert a significant influence on the polymorphic outcome of ball mill grinding by allowing the selective isolation of two polymorphic forms in their pure form under the same grinding conditions. Furthermore, we show how apparent mechanochemical equilibria can be deceptive. Our results clearly demonstrate the need for careful design and interpretation of ball milling experiments beyond current thinking.
T2 - SALSA make and measure
CY - Online meeting
DA - 16.09.2021
KW - Mechanochemistry
KW - Energy
KW - Polymorph
KW - Cocrystal
PY - 2021
AN - OPUS4-53293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - Next Level Grazing Incidence, Part I: Standardization of Calibration and Alignment for Grazing Incidence Small-Angle (X-ray) Scattering
N2 - We present initial results of our survey on grazing incidence methods which focuses on hardware, software, sample alignment and instrument calibration. We illustrate both sample alignment and sample-to-detector distance calibration with data recorded at the MOUSE and conclude with promising results from our Bayesian beam optimization procedure based on Gaussian Process regression.
T2 - XIX edition of the International Small-Angle Scattering Conference (SAS2024)
CY - Taipei, Taiwan
DA - 04.11.2024
KW - Standardisation
KW - Grazing incidence
KW - Sample alignment
KW - Instrument calibration
PY - 2024
AN - OPUS4-62775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Kochovski, Z.
A1 - Scoppola, E.
A1 - Retzmann, Anika
A1 - Hodoroaba, Vasile-Dan
A1 - ten Elshof, J. E.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz Maciej
T1 - Nonclassical Crystallization Pathway of Transition Metal Phosphate Compounds
N2 - Here, we elucidate nonclassical multistep crystallization pathways of transition metal phosphates from aqueous solutions. We followed precipitation processes of M-struvites, NH4MPO4·6H2O, and M-phosphate octahydrates, M3(PO4)2·8H2O, where M = Ni, Co, or NixCo1–x, by using in situ scattering and spectroscopy-based techniques, supported by elemental mass spectrometry analyses and advanced electron microscopy. Ni and Co phosphates crystallize via intermediate colloidal amorphous nanophases, which change their complex structures while agglomerating, condensing, and densifying throughout the extended reaction times. We reconstructed the three-dimensional morphology of these precursors by employing cryo-electron tomography (cryo-ET). We found that the complex interplay between metastable amorphous colloids and protocrystalline units determines the reaction pathways. Ultimately, the same crystalline structure, such as struvite, is formed. However, the multistep process stages vary in complexity and can last from a few minutes to several hours depending on the selected transition metal(s), their concentration, and the Ni/Co ratio.
KW - Non-classical crystallization theory
KW - Transition metals
KW - Phosphates
KW - Amorphous phases
KW - Intermediate phases
PY - 2023
DO - https://doi.org/10.1021/acs.chemmater.3c02346
SN - 1520-5002
VL - 35
IS - 24
SP - 10645
EP - 10657
PB - American Chemical Society (ACS)
CY - Washington D.C.
AN - OPUS4-59135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wahl, S.
A1 - El-Refaei, S. M.
A1 - Amsalem, P.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Koch, N.
A1 - Pinna, N.
T1 - Operando diffuse reflectance UV-vis spectroelectrochemistry for investigating oxygen evolution electrocatalysts
N2 - The characterization of the active structure of water-splitting catalysts is crucial to evolve to a sustainable energy future based on hydrogen. Such information can only be obtained by operando methods. We present a diffuse reflectance UV-vis (DRUV) spectroelectrochemical study that allows tracking the changes of solid oxygen evolution catalysts under working conditions. The versatility of our approach is demonstrated on two cobalt-containing catalysts, Zn0.35Co0.65O and CoAl2O4. The changes the catalysts undergo during the oxygen evolution reaction can be tracked by probing the electronic structure using UV-vis spectroscopy. These findings are compared to ex situ analyses, which support the assignments of the structures stabilized under different potentials. Thus, structure–activity correlations can be proposed, and deeper insights into the catalytically active structures can be obtained.
KW - EXAFS
PY - 2020
DO - https://doi.org/10.1039/c9cy02329a
VL - 10
IS - 2
SP - 517
EP - 528
PB - Royal Society of Chemistry
AN - OPUS4-50468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heilmann, Maria
T1 - Synthesis of Bimetallic Nickel Nanoparticles as Catalysts for the Sabatier Reaction
N2 - Nanoparticles (NP) have become important materials for a variety of chemical technologies. The enhance surface-area-to-volume ratio of NPs is very high, making them excellent for use as catalyst, in analytical assays, and for antimicrobial applications.
Nickel NPs have exhibited immense potential as important catalyst for the Sabatier reaction, i.e. converting waste to energy via transformation of CO2 into CH4, and could replace the rare earth elements such as Ru, PT, or Rh. In this work we describe the solvothermal synthesis of monometallic and bimetallic nickel nanoparticles.
Monodisperse monometallic Ni nanoparticles were synthesized using Oleylamin as solvent and reducing agent. The nanoparticles were investigated using small angle scattering (SAXS), scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX), showing that the catalytically active sites are accessible. However, Ni has a high propensity to undergo oxidation, and becoming deactivated by coke formation. Hence, we further explore the preparation of bimetallic NPs, where a second metal is added to stabilize the Ni.
Bimetallic Cu-Ni NPs were synthesized by simultaneous solvothermal reduction. These bimetallic NPs exhibit excellent catalytic properties are promising candidates to be used as catalysts for efficient energy storage.
T2 - Joint Polish-German Crystallographic Meeting
CY - Wroclaw, Poland
DA - 24.02.2020
KW - Nanoparticles
KW - Synthesis
KW - Catalysis
PY - 2020
AN - OPUS4-51663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Braun, U.
A1 - Herper, D.
A1 - Knefel, M.
A1 - Bednarz, M.
A1 - Bannick, C.-G.
T1 - Smart filters for the analysis of microplastic in beverages filled in plastic bottles
N2 - The occurrence of microplastic (MP) in food products, such as beverages in plastic bottles, is of high public concern. Existing analytical methods focus on the determination of particle numbers, requiring elaborate sampling tools, laboratory infrastructure and generally time-consuming imaging detection methods. A comprehensive routine analysis of MP in food products is still not possible. In the present work, we present the development of a smart filter crucible as sampling and detection tool. After filtration and drying of the filtered-off solids, a direct determination of the MP mass content from the crucible sample can be done by thermal extraction desorption gas chromatography mass spectroscopy (TED-GC/MS). The new filter crucible allows a filtration of MP down to particle sizes of 5 µm. We determined MP contents below 0.01 µg/L up to 2 µg/L, depending on beverages bottle type. This may be directly related to the bottle type, especially the quality of the plastic material of the screw cap. Dependent on the plastic material, particle formation increases due to opening and closing operations during the use phase. However, we have also found that some individual determinations of samples were subjected to high errors due to random events. A conclusive quantitative evaluation of the products is therefore not possible at present.
KW - Microplastic
KW - TED-GC/MS
KW - Plastic bottles
KW - Bbeverages
KW - Filter crucible
PY - 2021
DO - https://doi.org/10.1080/19440049.2021.1889042
SN - 1944-0057
VL - 38
IS - 4
SP - 691
EP - 700
PB - Taylor & Francis
AN - OPUS4-52323
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Repräsentative Untersuchungsstrategien für ein integratives Systemverständnis von spezifischen Einträgen von Kunststoffen in die Umwelt (RUSEKU)
N2 - Der Vortrag wurde im Rahmen der Abschlusskonferenz des Forschungsschwerpunktes "Plastik in der Umwelt" des BMBF gehalten. Er fasst die Ergebnisse des Verbundprojektes RUSEKU zusammen. Es wurde die Herstellung verschiedener Testmaterialien für die Mikroplastik (MP) Analytik beschrieben. Im weiteren geht es um verschiedene Ansätze MP kostengünstig und schnell zu detektieren, z.B. mit Nahinfrarotspektroskopie. Nanoplastik konnte mit der Transmissionselektronenmikroskopie sichtbar gemacht werden. Für die praxisnahe Beprobung von Gewässern wurde die Fraktionierte Filtration entwickelt. Integrale Beprobungen können mit dem Sedimentationskasten erfolgen. Als Beispiele für die Beprobung realer Gewässer wurde das urbane Abwassersystem Kaiserslautern, Getränkewasser und Waschmaschinenwasser gezeigt.
T2 - Abschlusskonferenz des Forschungsschwerpunktes "Plastik in der Umwelt" des BMBF
CY - Online meeting
DA - 20.04.2021
KW - Mikroplastik
KW - TED-GC/MS
KW - Probennahme
KW - RUSEKU
PY - 2021
AN - OPUS4-52546
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Mikroplastik an der BAM: TED-GC/MS und Referenzmaterialien
N2 - Thema ist die Funktionsweise der TED-GC/MS als Methode für die Mikroplastik-Detektion sowie die Herstellung dazugehöriger Referenzmaterialien an der BAM
T2 - 25. Kolloquium Massenspektrometrie von Polymeren
CY - Online meeting
DA - 17.06.2021
KW - Mikroplastik
KW - TED-GC/MS
KW - Referenzmaterial
PY - 2021
AN - OPUS4-52835
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Results of the Plastic in the environment comparative test
N2 - The talk describes the sturcture and the results of the "plastics in the environment" comparative test of 2019.
T2 - Symposium "Challenges of microplastic analysis – Bridging state of the art and policy needs”
CY - Online meeting
DA - 09.09.2021
KW - Microplastic
KW - Comparative test
KW - ILC
PY - 2021
AN - OPUS4-53236
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Linberg, Kevin
T1 - Insights into Mechanochemical Reactions using High Pressure XRD and DFT Simulations
N2 - The reactivity of organic solids under mechanochemical conditions remains very little understood, though many processes have been found empirically. Importantly, it is not well understood how mechanical treatment induces experimentally observed chemical transformations, and if the elevated pressures arising at the point of impact can play a role in the transformation. To understand this aspect of the mechanochemical reactions, the same compounds need to be explored under high pressure conditions. As a model system, we considered the reaction between the bis(4-chlorophenyl) disulfide and bis(2-nitrophenyl) disulfide. A powder mixture of these two compounds is known to undergo a disulfide exchange reaction under ball milling conditions. Using a combination of X-ray powder diffraction and dispersion-corrected density functional theory calculations, we investigated how this binary solid system behaves at elevated pressures and whether pressure alone can explain its mechanochemical reactivity.
T2 - International Scientific Student Conference 2021
CY - Online meeting
DA - 12.04.2021
KW - Mechanochemistry
KW - High Pressure
KW - Density-functional theory
PY - 2021
AN - OPUS4-52494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lakshmipathi, M.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
A1 - Ghosh, S.
T1 - Structure-mechanical property correlation of a series of 4-(1-Napthylvinyl) pyridine based cocrystals
N2 - We obtained three 4-(1-Napthylvinyl) pyridine based cocrystals ( 1–3 ) and studied its structure mechan- ical property correlation which aimed towards various applications for photo switches, mechanical ac- tuators etc. Selection of coformer molecules is important in fine tuning mechanical property outcome of synthesized cocrystals. Amongst three cocrystals, cocrystal 1 is mechanically flexible and its mechani- cal property is attributed to underlying crystal packing features which is in line with existing elastically bendable crystals while other two cocrystals ( 2, 3 ) are brittle in nature. Hirshfeld analysis was carried out to illustrate structure-property correlation particularly in terms of number as well as types of non- covalent interactions in the lattice and further to corroborate the space of the molecules in the lattice.
KW - Cocrystals
KW - Mechanical properties
KW - Halogen bond interaction
KW - Structure-mechanical property correlation
PY - 2022
DO - https://doi.org/10.1016/j.molstruc.2022.133670
SN - 0022-2860
VL - 1268
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Waniek, Tassilo
T1 - The practical implementation of MP reference material production according to ISO standards
N2 - Micro- and nanoplastic particles became a topic of public concern all over the world e.g. in water, soil, sludge and air. For a profound risk assessment, it is necessary to identify the origins, hotspots, or transport between different media. Therefore, a representative repeatable analysis is required and reference materials (RM) to proof and compare methods.
The basis of MNP investigations is a harmonized analysis which includes sampling, sample preparation and detection. In recent years, spectroscopic methods like µRaman and µFTIR for the determination of particle numbers or thermoanalytical methods like Pyrolysis gas chromatography/mass spectrometry (py-GC/MS) and Thermo extraction/ desorption gas chromatography / mass spectrometry (TED-GC/MS) for mass determination have proven to be particularly suitable.
The technical committees (TC) of ISO TC 61 “plastics” and TC 147 “water quality" are working on harmonisation processes on international level. For all standardization approaches, it is necessary that the detection methods and analysis processes can be validated. Therefore, BAM develops reference material for microplastic (MP) analysis for several years with focus on the most common polymers PE, PP, PS, PET and PA.
MP particles with a close to reality fragment shape are obtained by cryomilling and sieving. For sample preparation purposes with mass detection methods MP particles are pressed into pills with a water-soluble matrix. Thereby losses due to sample preparation e.g. filtration are included in the verification of an analysis.
To ensure a constant quality throughout all MP RM batches the homogeneity and stability is controlled according to ISO Guide 35. Next to TED-GC/MS measurements particle size distribution, infrared spectroscopy and differential scanning calorimetry spectra are taken as accompanying parameters.
This presentation aims to introduce into the MP RM production process with ensured quality and special focus on pointing out customized setups for particle comminution, separation, and characterization for standardization.
T2 - ASTM Syposioum on Microplastic Analytical and Reference Standards - Opportunities to Advance Microplastic Science
CY - Seattle, WA, USA
DA - 30.06.2022
KW - Microplastic
KW - Reference material
KW - Cryo milling
KW - Polymer
PY - 2022
AN - OPUS4-55891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 33th European Crrystallography Meeting
CY - Versailles, France
DA - 23.08.2022
KW - Mechanochemistry
KW - Cocrystals
KW - Kinetics
KW - Polymorphs
PY - 2022
AN - OPUS4-55586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, U.
T1 - Detection of plastics in soil
N2 - Soil acts as a final sink for pollutants. Microplastics from different sources such as plastic mulching, littering, compost, sewage sludge, sedimentary deposition, and tyre abrasion are expected to be found in soil. However, representative and comprehensive information is missing on the sources, transport, and fate. Therefore, a reliable analysis method for microplastics in soils needs to be developed.
The presented work describes the development of a procedure for microplastics analysis in soils. A representative sampling based on the on-site conditions and a sample preparation method was established and comprised of a drying step, the separation of microplastic particles > 1 mm, and a density separation for particles < 1 mm. The detection of the large microplastic particles (> 1 mm) was conducted with Attenuated Total Reflection - Fourier Transform infrared Spectroscopy (ATR-FTIR) , while Thermal Extraction Desorption - Gas Chromatography / Mass Spectrometry (TED-GC/MS) was applied for particles < 1 mm, gaining information on the type of polymer and mass fraction. Based on the established method, 14 environmental soil samples ? with different exposure of microplastics from agriculture, industrial sites, roads, and floods were investigated.
Due to the arbitrary microplastic particle distribution among the samples for large microplastics, it was reasoned that the found particles were unrepresentative. In contrast, microplastic particles < 1 mm were discovered in a high mass in soil samples exposed to plastic mulching or fertilization with sewage sludge or compost (0 – 115 mg/kg). On average, microplastic contents detected in soil samples taken from a construction site and an inner-city lake were higher (13 – 238 mg/kg). As expected, microplastic content in soil sampled in proximity to roads was more pronounced in the upper soil layers. In contrast, very remote sampling sites, expectably uncontaminated, did not lead to the detection of microplastic regarding to thermoanalytical detection method.
In a proof of concept experiment several in vivo and in vitro ecotoxicological tests were applied to evaluate the effect of microplastics (tyre abrasion, polystyrene containing hexabromocyclododecane) in natural soils. In summary, while no effects of the examined probes could be detected on higher levels of biological organization after exposures to earthworm E. andrei, significant changes in several oxidative stress related biomarkers were observed.
T2 - SETAC Europe 2022
CY - Kopenhagen, Denmark
DA - 15.05.2022
KW - Microplastic
KW - TED-GC/MS
KW - Soil
PY - 2022
AN - OPUS4-55872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics
N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes.
T2 - 3rd CEFMC meeting
CY - Kashmir, India
DA - 31.08.2022
KW - Mechanochemistry
KW - Crystal Engeneering
PY - 2022
AN - OPUS4-55641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Harmonisation efforts of the CUSP projects
N2 - The talk is about harmonisation approaches within CUSP. First the five H2020 projects for research on risk assessment regarding microplastics topic were presented. Secondly, harmonisation process were discussed.
T2 - VAMAS SC 47 Meeting
CY - Turin, Italy
DA - 19.10.2022
KW - Microplastics
KW - Harmonisation
KW - Nanoplastics
KW - H2020
KW - Risk assessment
PY - 2022
AN - OPUS4-56077
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, U.
T1 - Analysis of Microplastics in Soil: Harmonisation and Standardisation - a first approach
N2 - The talk is about microplastics in soil. Some results were presented with mainly state of the art according to microplastics in standardization.
T2 - International Conference Microplastics in Soils
CY - Berlin, Germany
DA - 19.10.2022
KW - Microplastics
KW - Microplastics standardisation
KW - Microplastics in soil
PY - 2022
AN - OPUS4-56078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Welche Rolle spielen Textilien als Mikroplastik-Quelle im Abwasser? Was kann man dagegen tun?
N2 - Diskutiert wird die Frage, ob Textilien gewaschen in der Waschmaschine ein Eintragspfad von Mikroplastik in die Umwelt sind. Nachgewiesen wird dies experimentell über Messungen zur Massenbestimmung mit der TED-GC/MS.
T2 - DWA-Seminar: Mikroplastik in der (Siedlungs-)Wasserwirtschaft – Einordnung und Handlungsempfehlungen für die Praxis
CY - Online meeting
DA - 29.11.2023
KW - Mikroplastik
KW - TED-GC/MS
KW - Waschmaschine
KW - Polymer 3R
PY - 2023
AN - OPUS4-59279
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Kazlagić, Anera
T1 - Provenancing of cement by the means of isotope techniques
N2 - Concrete is the most important human-made material because it serves as the basis of our built environment. Since the properties of concretes are dominated by their key compound, cement, devising a way to determine the cement’s origin, known as provenancing, is of great importance for answering different provenance-related questions. These questions range from liability issues when damage occurs to concrete-made structures, to forensic investigations where cement particles are found at crime scenes. This thesis showcases the use of isotope techniques to answer these provenance-related questions. Conventional 87Sr/86Sr and 143Nd/144Nd isotope and elemental ratios consisting of Ca, Sr, K, Mn, Mg, and Ti are used as fingerprints for ordinary Portland cement (OPC) provenancing. The first part of this thesis describes research previously conducted in fingerprinting cementitious materials, providing an overview of provenance studies of cement and the main approaches commonly used. In several studies, the origin of clinker for certain locations was determined via different approaches. However, clinker is an intermediate product, which is available only at the production site and therefore, the practical relevance is rather limited. Furthermore, the use of Sr and Nd isotope systems, together with elemental fingerprints are presented as state of the art in the field. Therein, the principal approach for the overall study is sketched. For the second part of the study, a sample preparation technique for Sr isotopes in Portland cement was developed. The aim was to find the most appropriate sample preparation procedure for cement provenancing and selection was realised by comparing the 87Sr/86Sr isotope ratios of differently treated OPCs with those of the corresponding clinkers. Based on these findings, the third part of the study focused on the measurements of Sr and Nd isotope ratios, together with elemental ratios, to establish a reliable technique for OPC provenancing. The outcomes of this final stage are then used to establish a procedure for fingerprinting cements. This becomes possible with the use of Sr and Nd isotope ratios and geochemical profiles. To perform isotope ratio measurements and obtain reliable data, it was necessary to establish a quality control procedure. Thus, an interlaboratory comparison (ILC) was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the conventional method for 87Sr/86Sr isotope ratios. As reference material, four cements (VDZ 100a, VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG/CGL ML-3) and one slate (IAG OU-6) were selected, thus covering a wide range of Sr isotope signatures.
KW - Isotope ratio
KW - Strontium
KW - Neodymium
KW - Ordinary Portland cement
PY - 2023
SP - 1
EP - 148
CY - Berlin
AN - OPUS4-59172
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Understanding mechanochemical reactions: Real-time insights and collaborative research
N2 - Mechanochemistry emerges as a potent, environmentally friendly, and straightforward approach for crafting novel multicomponent crystal systems. Various milling parameters, including milling frequency, time, filling degree of the milling jar, ball diameter, vessel size, degree of milling ball filling, and material of jars, are recognized influencers on the mechanisms and rates of product formation. Despite the growing interest in mechanochemistry, there exists a gap in understanding the mechanistic aspects of mechanochemical reactivity and selectivity. To address this, diverse analytical methods and their combinations, such as powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography, have been developed for real-time, in situ monitoring of mechanochemical transformations.
This discussion centers on our recent findings, specifically investigating the formation of (polymorphic) cocrystals and metal-organic frameworks. Through these studies, we aim to unravel the impact of milling parameters and reaction sequences on the formation mechanism and kinetics. Notably, in the mechanochemical chlorination reaction of hydantoin, normalizing kinetic profiles to the volume of the milling ball unequivocally demonstrates the conservation of milling reaction kinetics. In this ball-milling transformation, physical kinetics outweigh chemical factors in determining reaction rates. Attempting to interpret such kinetics solely through chemical terms poses a risk of misinterpretation. Our results highlight that time-resolved in situ investigations of milling reactions provide a novel avenue for fine-tuning and optimizing mechanochemical processes.
T2 - PhD Seminar
CY - Online meeting
DA - 12.10.2023
KW - Mechanochemistry
KW - In situ
PY - 2023
AN - OPUS4-59022
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Investigating the mechanism and kinetics of the mechanochemical synthesis of multi-component systems
N2 - Mechanochemistry is a promising and environmentally friendly approach for synthesizing (novel) multicomponent crystal systems. Various milling parameters, such as milling frequency, milling time, and ball diameter have been shown to influence the mechanisms and rates of product formation. Despite increasing interest in mechanochemistry, there is still limited understanding of the underlying reactivity and selectivity mechanisms.
Various analytical techniques have been developed to gain insight into the mechanochemical transformations, including powder X-ray diffraction, X-ray adsorption spectroscopy, NMR, Raman spectroscopy and thermography. Using these techniques, we have studied the formation of (polymorphic) cocrystals, organometallic compounds and salts, and elucidated the influence of milling parameters and reaction sequences on the formation mechanism and kinetics.
For example, our study of the mechanochemical chlorination reaction of hydantoin revealed that normalisation of the kinetic profiles to the volume of the grinding ball clearly showed that physical kinetics dominate the reaction rates in a ball-milling transformation. Attempts to interpret such kinetics in purely chemical terms risk misinterpretation of the results.
Our results suggest that time-resolved in situ investigation of milling reactions is a promising way to fine-tune and optimise mechanochemical processes.
T2 - ISIC 2023
CY - Glasgow, Scotland
DA - 05.09.2023
KW - Mechanochemistry
KW - Polymorphy
KW - In situ
PY - 2023
AN - OPUS4-59023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Combination of complementary methods For in situ studies
N2 - This talk explores the synergistic application of complementary synchrotron methods for in situ investigations, providing a comprehensive approach to enhance analytical capabilities in materials research and characterization.
T2 - INSYNX - DEUTSCH-BRASILIANISCHER WORKSHOP ON BREAKING BOUNDARIES OF IN SITU SYNCHROTRON X-RAY METHODS
CY - Sao Paulo, Brazil
DA - 06.03.2023
KW - In situ
KW - Synchrotron
PY - 2023
AN - OPUS4-59025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Understanding mechanochemical reactions: Real-time insights and collaborative research
N2 - Mechanochemistry emerges as a potent, environmentally friendly, and straightforward approach for crafting novel multicomponent crystal systems. Various milling parameters, including milling frequency, time, filling degree of the milling jar, ball diameter, vessel size, degree of milling ball filling, and material of jars, are recognized influencers on the mechanisms and rates of product formation. Despite the growing interest in mechanochemistry, there exists a gap in understanding the mechanistic aspects of mechanochemical reactivity and selectivity. To address this, diverse analytical methods and their combinations, such as powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography, have been developed for real-time, in situ monitoring of mechanochemical transformations.
This discussion centers on our recent findings, specifically investigating the formation of (polymorphic) cocrystals and metal-organic frameworks. Through these studies, we aim to unravel the impact of milling parameters and reaction sequences on the formation mechanism and kinetics. Notably, in the mechanochemical chlorination reaction of hydantoin, normalizing kinetic profiles to the volume of the milling ball unequivocally demonstrates the conservation of milling reaction kinetics. In this ball-milling transformation, physical kinetics outweigh chemical factors in determining reaction rates. Attempting to interpret such kinetics solely through chemical terms poses a risk of misinterpretation. Our results highlight that time-resolved in situ investigations of milling reactions provide a novel avenue for fine-tuning and optimizing mechanochemical processes.
T2 - Brimingham Green chemistry
CY - Birmingham, England
DA - 08.09.2023
KW - Mechanochemistry
KW - Green Chemistry
PY - 2023
AN - OPUS4-59024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Understanding mechanochemical reactions: Real-time insights and collaborative research
N2 - Mechanochemistry has become a compelling method for producing (new) molecule s and mate-rials, but the inner workings of the milling jars remain a fascinating mystery. Advances in this field include tailor-made chemical systems and real-time revelations using techniques such as XRD and Raman spectroscopy.
This talk will discuss our recent progress in using X-ray diffraction and sophisticated spectros-copy to observe reactions in various material systems during ball milling and extrusion in real-time.
The complexity of mechanochemical reactions spans multiple scales and requires a holistic ap-proach. The categorisation of reactions by investigative methods precedes the exploration of real-time analysis that reveals macroscopic processes using synchrotron techniques.
During this exploration, one resounding realisation remains: We are on the threshold of under-standing. The complexity of mechanochemistry requires a collective effort, drawing on the ex-pertise of a diverse community. As we unravel the web of mechanochemical phenomena, we acknowledge the collaborative nature of this ongoing journey.
T2 - CMCC Mechanochemistry Discussions
CY - Online meeting
DA - 21.09.2023
KW - Mechanochemistry
KW - In situ
PY - 2023
AN - OPUS4-59026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Getting reliable data on microplastic detection methods by means of ILC
N2 - There is an urgent demand for reliable data on microplastic analysis, particularly on its physico-chemical properties as well as validated methodology to obtain such data. Through interlaboratory comparisons (ILCs) it becomes possible to assess accuracy and precision of methods by involving many laboratories around the world. At BAM, my tasks focused around organisation of an ILC on physico-chemical characterisation of microplastic detection methods under the international pre-standardisation platform VAMAS (www.vamas.org/twa45/) as Project 2 “Development of standardized methodologies for characterisation of microplastics with microscopy and spectroscopy methods” under the Technical Working Area TWA 45 “Micro and Nano Plastics in the Environment”.
With a proud number of 84 participants this ILC is able to provide superior statistical results. Thermoanalytical (Py-GC/MS and TED-GC/MS) and vibrational (µ-IR and µ-Raman) methods were asked for identification and quantification of microplastic test samples according to mass or particle number. Preliminary results indicate which methods show a higher accuracy and precision and reveal some sample preparation ideas which work best for microplastics characterisation. At the end of the ILC an overall plausibility of the results will be assessed.
T2 - CUSP Early Career Researchers Meeting
CY - Online meeting
DA - 21.11.2023
KW - Micro- and Nanoplastics
KW - Interlaboratory comparison
KW - Microplastic reference materials
PY - 2023
AN - OPUS4-59056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Emmerling, Franziska
T1 - Connecting the nodes: networks and networking
N2 - This talk explores the intricate connections between scientists, focusing on the networking dynamics within the realm of metal-organic frameworks (MOFs). The study delves into the collaborative networks formed among scientists, shedding light on the synergistic relationships that contribute to advancements in MOF research.
T2 - WINS School 2023 Frameworks and networks
CY - Blossin, Germany
DA - 02.06.2023
KW - Metal-organic frameworks
PY - 2023
AN - OPUS4-59028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casali, Lucia
T1 - Use of the solvent-free mechanochemical method for a sustainable preparation of pharmaceuticals
N2 - With the growing interest in environmental issues on the part of governments and institutions, pharmaceutical industries are asked to reduce their environmental footprint. Given the major impact related to the use of solvents, the development of methodologies less solvent demanding is nowadays even more urgent. In light of that, mechanochemistry would be a suitable solvent-free technology since it promotes the activation of the chemical reactions between (generally) solid materials via inputs of mechanical energy. Since such reactions may occur outside the kinetic and thermodynamic rules of conventional solution chemistry, the main limit of mechanochemistry is the poor mechanistic understanding of the solid-state transformations involved, which is still hindering a widespread use of the method, as well a scale-up to the industrial level. However, the development of methods for real-time monitoring of the mechanochemical reactions enables obtaining (in)accessible information on reaction intermediates, new products, or reaction time, thus getting closer to a better understanding of the mechanistic behaviour. With the rules of this chemistry becoming increasingly clear, the new reaction pathways of mechanochemistry wouldn’t represent a limit anymore, but an asset, that may lead to lot of opportunities for the pharmaceutical industry.
T2 - Post Doc Day Berlin
CY - Berlin, Germany
DA - 02.11.2023
KW - Mechanochemistry
KW - Sustainability
KW - Pharmaceuticals
PY - 2023
AN - OPUS4-59010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Somasundaram, S. K.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Krishnan, S.
A1 - Senthilkumar, K.
A1 - Joseyphus, R.J.
T1 - New insights into pertinent Fe-complexes for the synthesis of iron via the instant polyol process
N2 - Chemically synthesized iron is in demand for biomedical applications due to its large saturation magnetization compared to iron oxides. The polyol process, suitable for obtaining Co and Ni particles and their alloys, is laborious in synthesizing Fe. The reaction yields iron oxides, and the reaction pathway remains unexplored. This study shows that a vicinal polyol, such as 1,2-propanediol, is suitable for obtaining Fe rather than 1,3-propanediol owing to the formation of a reducible Fe intermediate complex. X-ray absorption spectroscopy analysis reveals the ferric octahedral geometry and tetrahedral geometry in the ferrous state of the reaction intermediates in 1,2-propanediol and 1,3-propanediol, respectively. The final product obtained using a vicinal polyol is Fe with a γ-Fe2O3 shell, while the terminal polyol is favourable for Fe3O4. The distinct Fe–Fe and Fe–O bond lengths suggest the presence of a carboxylate group and a terminal alkoxide ligand in the intermediate of 1,2-propanediol. A large Fe–Fe bond distance suggests diiron complexes with bidentate carboxylate bridges. Prominent high-spin and low-spin states indicate the possibility of transition, which favors the reduction of iron ions in the reaction using 1,2-propanediol.
KW - XAS
KW - Nanoparticle
PY - 2023
DO - https://doi.org/10.1039/D3CP01969A
SN - 1463-9076
VL - 25
IS - 33
SP - 21970
EP - 21980
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58073
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Surov, A.
A1 - Vasilev, N.
A1 - Voronin, A.
A1 - Churakov, A.
A1 - Emmerling, Franziska
A1 - Perlovich, G.
T1 - Ciprofloxacin salts with benzoic acid derivatives: structural aspects, solid-state properties and solubility performance
N2 - n this work, three new pharmaceutical hydrated salts of ciprofloxacin with selected derivatives of benzoic acid, namely 4-hydroxybenzoic acid, 4-aminobenzoic acid and gallic acid, were obtained and systematically investigated by several solid-state analytical techniques. In situ Raman spectroscopy was applied to elucidate the alternative pathways of the solid forms' formation under mechanochemical conditions. Crystal structure analysis and a CSD survey allowed us to establish a distinct supramolecular motif formed by infinite columnar stacks of ciprofloxacin dimers arranged in the “head-to-tail” manner. An alternative “head-to-head” packing arrangement was only observed in the crystal of the hydrated ciprofloxacin salt with 4-aminobenzoic acid. In addition, the pH-solubility behavior of the solid forms was thoroughly investigated. Furthermore, a distinct structure–property relationship between the specific features of the supramolecular organization of the hydrated salts and their solubility was observed and discussed.
KW - Mechanochemistry
KW - XRD
PY - 2020
DO - https://doi.org/10.1039/D0CE00514B
VL - 22
IS - 25
SP - 4238
EP - 4249
AN - OPUS4-51818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Altmann, Korinna
T1 - Deliverable 2: Summary report on: The development of pristine SI traceable reference materials for SMPs (0.1 μm - 10 μm) and NPs (< 0.1 μm), representative of partially degraded/naturally aged samples in complex food and environmental matrices, and for realistic polydisperse size distributions and irregular shapes
N2 - PlasticTrace aims to address the urgent need for development and harmonisation of methods for the chemical identification, physical characterisation and quantification of released small micro/nanoplastics (SMPs/NPs) in drinking water, food and environmental matrices, as required by the EU’s Circular Economy Action Plan (CEAP). This report describs the characterisation of nanoPP analysed in the PlasticTrace project aiming to develop a reference material. The nanoPP was analysed mainly by light scattering methods. Homogeneity control was done by DLS.
KW - Nanoplastics
KW - Reference materials
PY - 2024
N1 - Project Number 21GRD07: PlasticTrace (Tracing Micro and NanoPlastics in Food and Environment), funded by the European Union
SP - 1
EP - 29
PB - European Association of National Metrology Institutes (EURAMET)
CY - Braunschweig
AN - OPUS4-62299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goswami, Juli Nanda
A1 - Haque, Najirul
A1 - Seikh, Asiful H.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Bar, Nimai
A1 - Ifseisi, Ahmad A.
A1 - Biswas, Surajit
A1 - Dolai, Malay
T1 - Carboxylative cyclization of propargyl alcohols with carbon dioxide for the synthesis of α-alkylidene cyclic carbonates in presence of Co(III) schiff base complex catalyst
N2 - A cobalt(III) complex, [Co(L)3](DMF) (1) of Schiff base ligand HL, 2-((E)-(benzylimino)methyl)-4-bromophenol is prepared and single crystal X-ray structural analysis have also been performed. The structures of complex 1 showed hexa-coordinated mononuclear systems that adopt octahedral geometry. The complex has also exhibited the supramolecular networks through non-covalent interactions like H-bonding, C–Hπ stacking. Moreover, the complex 1 is very effective in the catalytic fixation of carbon dioxide in propergyl alcohols to produce α-alkylidene cyclic carbonates. The catalytic production of α-alkylidene cyclic carbonates have been carried out through carboxylative cyclization of propargyl alcohols using CO2 balloon of 1 atm pressure at 80 ◦C. Solvent free condition (green synthesis) made this catalytic protocol eco-friendly towards the environment. Utilizing various substrates of propargyl alcohols moderate to high percentage yield (62–95%) of respective α-alkylidene cyclic carbonates product have been isolated over this catalytic reaction. Besides, the theoretical calculations (DFT) was performed for the prediction of probable mechanism of the catalytic reaction
KW - Catalytic fixation of carbon dioxide
KW - Carboxylative cyclization of propargyl alcohols
KW - Cobalt (III) Schiff base complex
KW - X-ray crystal analysis
PY - 2024
DO - https://doi.org/10.1016/j.molstruc.2023.136868
SN - 0022-2860
VL - 1296
IS - Part 1
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-58947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karafiludis, Stephanos
A1 - Stawski, Tomasz
T1 - Deciphering the non-classical Crystallization of transition metal phosphates (TMP)
N2 - A crucial aspect of ensuring sustainable raw material utilization to meet global demand lies in the efficient recovery and reuse of critical elements and compounds. Phosphate, PO43-, and many transition metals e.g. Ni and Co are listed as critical raw materials (CRMs) due to their indispensable role in numerous industrial processes. However, these elements can also exert harmful environmental impacts, with phosphorus being a major contributor to anthropogenic eutrophication and transition metal ions acting as toxic pollutants, particularly in ground- and wastewaters. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we report the crystallization pathways of transition metal phosphate (TMP) compounds, M-struvite and M-phosphate octahydrate with M = Ni2+, Co2+, NixCo1-x2+, NH4MPO4∙6H2O, M3(PO4)2∙8H2O from aqueous solutions. The co-precipitation of these particular TMP compounds from industrial and agricultural wastewaters has high potential as a P- and 3d metal recovery route.
For efficient extraction and transformation of the TMPs, a comprehensive understanding of their nucleation and crystallization pathways from aqueous solutions is required. While the crystallization mechanisms of magnesium or calcium phosphate-bearing phases have been researched for many decades (e.g. struvite, apatite), investigations into TMP materials are relatively scarce and often focus on the adsorption of transition metals on the surface instead of their actual incorporation in minerals. In our study, we investigated in detail the precipitation process of several Co and Ni phosphates using ex- and in-situ spectroscopic-, spectrometric- and diffraction-/scattering-based techniques. We show that the crystallization behavior of TMPs, indeed deviates from a classical crystallization paradigm and follows a non-classical multi-step pathway. Our work extends the understanding of TMP crystallization by elucidating the formation of amorphous precursors preceding the final crystalline phase This time-dependent transition of the transition metal precursor phases can be observed by electron-imaging/tomography depicting a progressively changing amorphous solids until their ultimate reconfiguration to a crystal (Figure 1). Here, the two-metallic NixCo1-x-mixtures deviated anomalously in their reaction kinetics, crystallization outcome and participation of both metals from their pure endmembers. By measuring the crystallization with in-situ X-ray scattering and pH using a flow-through setup geometry, a complex prolonged interplay among nucleating entities e.g. and amorphous or crystalline solids could be observed in the metal phosphate mixtures reaching equilibrium after almost two and a half hours (Figure 2). Our results provide a holistic perspective on the crystallization behavior of transition metal phosphate phases, shedding light on their unique nucleation and growth kinetics involving structural and chemical transformations of the intermediate phases.
T2 - Granada Münster Discussion Meeting 2023
CY - Münster, Germany
DA - 29.11.2023
KW - Non-classical crystallization theory
KW - Transition metals
KW - Phosphates
PY - 2023
AN - OPUS4-59007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pütz, E.
A1 - Smales, Glen Jacob
A1 - Jegel, O.
A1 - Emmerling, Franziska
A1 - Tremel, W.
T1 - Tuning ceria catalysts in aqueous media at the nanoscale: how do surface charge and surface defects determine peroxidase- and haloperoxidase-like reactivity
N2 - Designing the shape and size of catalyst particles, and their interfacial charge, at the nanometer scale can radically change their performance. We demonstrate this with ceria nanoparticles. In aqueous media, nanoceria is a functional mimic of haloperoxidases, a group of enzymes that oxidize organic substrates, or of peroxidases that can degrade reactive oxygen species (ROS) such as H2O2 by oxidizing an organic substrate. We show that the chemical activity of CeO2−x nanoparticles in haloperoxidase- and peroxidaselike reactions scales with their active surface area, their surface charge, given by the ζ-potential, and their surface defects (via the Ce3+/Ce4+ ratio). Haloperoxidase-like reactions are controlled through the ζ-potential as they involve the adsorption of charged halide anions to the CeO2 surface, whereas peroxidase-like reactions without charged substrates are controlled through the specific surface area SBET. Mesoporous CeO2−x particles, with large surface areas, were prepared via template-free hydrothermal reactions and characterized by small-angle X-ray scattering. Surface area, ζ-potential and the Ce3+/Ce4+ ratio are controlled in a simple and predictable manner by the synthesis time of the hydrothermal reaction as demonstrated by X-ray photoelectron spectroscopy, sorption and ζ-potential measurements. The surface area increased with synthesis time, whilst the Ce3+/Ce4+ ratio scales inversely with decreasing ζ-potential. In this way the catalytic activity of mesoporous CeO2−x particles could be tailored selectively for haloperoxidase- and peroxidase-like reactions. The ease of tuning the surface properties of mesoporous CeO2x particles by varying the synthesis time makes the synthesis a powerful general tool for the preparation of nanocatalysts according to individual needs.
KW - SAXS
KW - Ceria
KW - Zeta potential
PY - 2022
DO - https://doi.org/10.1039/D2NR03172H
SP - 1
EP - 12
PB - Royal Society of Chemistry
AN - OPUS4-55649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Reference material candidates for microplastic analysis
N2 - Every day, there are new headlines in the media about microplastics (1-1000 µm, ISO/TR 21960:2020) and nanoplastics (< 1 µm, ISO/TR 21960:2020) findings all over the planet with high variations in particle number and mass. The challenges in analytics are very complex, e.g. representative sampling, non-destructive sample preparation with concentrated particles and homogeneous distribution and true detection. All together lead to lacks in harmonization and results, which are hardly comparable. On the other hand, monitoring of microplastics is mandatory in the future strictly regulated by the EU commission in the Drinking water and Wastewater Framework Directive. One step to accurate and precise results will be the development of suitable reference materials mimicking particles in the environment.
BAM developed test materials, which are produced by mixing a small portion of microplastic particles with a water-soluble matrix. After solid phase dilution and homogenisation small portions are pressed into tablets and bottled in glass vials (Figure 1). These tablets are well characterized with particle size distribution and SEM images. Additionally, they are tested as reference material candidate according to homogeneity and stability for particle number with µ-IR and µ-Raman as well as on particle mass with Py-GC/MS and TED-GC/MS after ISO Guide 35. Results are promising. The material passed the homogeneity control. No changes are observed within 6 months of storage.
The same tested reference material is finally used in sample preparation experiments, where environmental suspended particular matter from surface water or baby milk powders are spiked with the tablets.
T2 - ESOPS
CY - Berlin, Germany
DA - 09.09.2024
KW - Microplastics
KW - TED-GC/MS
KW - Reference materials
KW - Polymer 3R
KW - Tablets
PY - 2024
AN - OPUS4-61017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Akhmetova, Irinia
A1 - Emmerling, Franziska
T1 - Mechanochemical and solution syntheses of two novel cocrystals of orcinol with two N,N0-Dipyridines: Structural diversity with varying ligand flexibility
N2 - We studied the influence of coformers flexibility on the supramolecular assembly of 5-substituted resorcinol. Two cocrystals of orcinol (ORL) with two dipyridine molecules, i.e. 1,2-di(4-pyridyl)ethane (ORLeBPE) and 1,2-di(4-pyridyl)ethylene (ORLeBPY), were prepared by mechanochemical synthesis and slow evaporation of solvent. The new crystalline solids were thoroughly characterized by single crystal Xray diffraction (SCXRD), powder X-ray diffraction analysis (PXRD), Fourier-transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Structural determination reveals that in both cocrystals, the phenolepyridine, i.e. OeH/N(py) heterosynthon takes the main role in the formation of cocrystals. In ORLeBPE, the components form infinite 1D zig-zag chains, which are extended to 2D layer structure by inter-chain CeH/O interactions between BPE hydrogen atoms and hydroxyl oxygen atoms of ORL. In ORLeBPY, the components form a 0D fourcomponent complex. Formation of the discrete assemblies is attributed to the comparative rigid nature of BPY, which restricts the formation of an extended network.
KW - Cocrystal
KW - Single crystal
KW - X-ray diffraction
KW - Mechanochemistry
PY - 2020
DO - https://doi.org/10.1016/j.molstruc.2020.128303
SN - 0022-2860
VL - 1217
SP - 128303
PB - Elsevier B.V.
AN - OPUS4-51023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Opitz, P.
A1 - Besch, L.
A1 - Panthöfer, M.
A1 - Kabelitz, Anke
A1 - Unger, R.
A1 - Emmerling, Franziska
A1 - Mondeshki, M.
A1 - Tremel, W.
T1 - Insights into the In Vitro Formation of Apatite from Mg‐Stabilized Amorphous Calcium Carbonate
N2 - A protein‐free formation of bone‐like apatite from amorphous precursors through ball‐milling is reported. Mg2+ ions are crucial to achieve full amorphization of CaCO3. Mg2+ incorporation generates defects which strongly retard a recrystallization of ball‐milled Mg‐doped amorphous calcium carbonate (BM‐aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg‐doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg2+ contents, BM‐aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg‐doped ACC forms in the presence of phosphate ions bone‐like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH−) and type B (PO43−) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin‐free material and makes BM‐aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases.
KW - Total Scattering
KW - XRD
KW - Mechanochemistry
PY - 2020
DO - https://doi.org/10.1002/adfm.202007830
VL - 31
IS - 3
SP - 7830
PB - Wiley VHC-Verlag
AN - OPUS4-51761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Alić Stolar, Jasna
T1 - Harnessing mechanochemistry to combat PFAS contamination
N2 - For over 70 years, the uncontrolled production, use, and disposal of per- and polyfluoroalkyl substances (PFAS) have led to widespread global contamination, necessitating the rapid development of innovative and efficient remediation technologies. State-of-the-art strategies rely on energy-intensive incineration, which releases greenhouse gases and smaller, volatile PFAS derivatives. Here, we present a fast, simple, and sustainable method for the complete degradation of PFAS leveraging mechanochemistry to break down the persistent carbon-fluorine bonds. Our findings indicate that liquid-assisted grinding conditions accelerate the degradation of perfluorooctanoic acid compared to neat grinding conditions, resulting in a significant reduction in energy consumption. Moreover, the fluoride released during the process binds to inorganic additives, allowing fluorine recovery as crystalline salts and preventing the formation of secondary toxic waste. The method has strong potential for scaling up and offers a green and viable solution for real-world application in PFAS decontamination.
T2 - The International Symposium on Mechanochemistry (Mech’cheM 2025)
CY - Montpellier, France
DA - 04.06.2025
KW - Mechanochemistry
KW - PFAS
PY - 2025
AN - OPUS4-63956
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Moss, Caitlin
T1 - Framework Materials for the Electrocatalytic Reduction of Nitrate to Ammonia
N2 - The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process while simultaneously addressing the pressing issue of nitrate pollution in water sources. Developing efficient catalysts for this reaction is therefore vital for both environmental remediation and green ammonia production. Framework materials such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and coordination polymers present an emerging class of electrocatalytic materials due to their high surface area, tunable porosity, and structural modularity. Their ability to incorporate diverse metal centers and functional groups makes them promising candidates for selective and efficient nitrate reduction. In order to change and improve catalytic properties, different synthesis strategies can be pursued, such as metal alloying or calcination under different conditions. To fully understand and optimize these materials, advanced characterization techniques are essential to correlate structural features with catalytic performance, alongside in-situ methods for real-time mechanistic insights.
T2 - Tag der Chemie 2025
CY - Berlin, Germany
DA - 03.07.2025
KW - Electrocatalysis
KW - Electrochemisty
KW - Framework Materials
KW - Ammonia Synthesis
KW - Nitrate Reduction
PY - 2025
AN - OPUS4-63815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmalz, Alina
T1 - Framework Materials for the Electrocatalytic Reduction of Nitrate to Ammonia
N2 - The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process while simultaneously addressing the pressing issue of nitrate pollution in water sources. Developing efficient catalysts for this reaction is therefore vital for both environmental remediation and green ammonia production. Framework materials such as metal-organic frameworks (MOFs) or metalated covalent organic frameworks (COFs) present an emerging class of electrocatalytic materials due to their high surface area, tunable porosity, and structural modularity. Their ability to incorporate diverse metal centers and functional groups makes them promising candidates for selective and efficient nitrate reduction. In order to change and improve catalytic properties, different synthesis strategies can be pursued, such as metal alloying, doping or calcination. To fully understand and optimize these materials, advanced characterization techniques are essential to correlate structural features with catalytic performance, alongside in-situ methods for real-time mechanistic insights.
T2 - 10th European Crystallography School
CY - Ohrid, North Macedonia
DA - 23.06.2025
KW - Electrocatalysis
KW - Electrochemistry
KW - Framework Materials
KW - Ammonia Synthesis
KW - Nitrate Reduction
PY - 2025
AN - OPUS4-63846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ryll, Tom William
T1 - In-situ analysis of nucleation processes – case study: calciumsulfate
N2 - In this project we investigate nucleation pathways by utilizing synchrotron-XRD and running a case-study on calcium sulfate and its polymorphs. To accomplish this, we developed a modular automation setup for reactions in solution to run synthesis and control reaction conditions. So far we successfully characterized the recycling process of gypsum (CaSO4*2H2O) and are now investigating the formation of anhydrite (CaSO4*0H2O) as well as possible applications for the automation setup and analysis.
T2 - SALSA Make & Measure 2025
CY - Berlin, Germany
DA - 10.09.2025
KW - Recycling
KW - Gypsum
KW - Synchrotron-X-ray-diffraction
KW - Raman-spectroscopy
KW - Automation
PY - 2025
AN - OPUS4-64135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Getting down to business: pragmatic solutions for laboratory automation
N2 - A chemical engineer by training, Brian drifted towards physics and now focuses on a broad spectrum of activities with the aim to improve scientific reproducibility. This includes studies on holistically improving data quality, data collection efficiency and traceability, as well as concomitant laboratory automation for the preparation of consistent, well-documented sample series. The need for pragmatism led to an inexpensive, flexible laboratory automation platform that can be implemented in a modest amount of time. This talk presents that effort.
T2 - Future Labs Live 2024
CY - Basel, Switzerland
DA - 25.06.2024
KW - Laboratory automation
KW - Experiment tracking
KW - Holistic experimentation
KW - Experimental traceability
KW - Data visualisation
KW - Parameter correlation.
PY - 2024
AN - OPUS4-60583
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Glimpses of the future: a “full stack”, highly automated materials research laboratory
N2 - In our (dramatically understaffed) X-ray scattering laboratory, developing a systematic, holistic methodology let us provide scattering and diffraction information for more than 2100 samples for 200+ projects led by 120+ collaborators. Combined with automated data correction pipelines, and our analysis and simulation software, this led to more than 40 papers in the last 5 years with just over 2 full-time staff members.
This year, our new, modular synthesis platform has made more than 1000 additional samples for us to analyse and catalogue. By virtue of the automation, the synthesis of these samples is automatically documented in excruciating detail, preparing them for upload and exploitation in large-scale materials databases. Having developed these proof-of-concepts, we find that materials research itself is changed dramatically by automating dull tasks in a laboratory.
This talk is intended to spark ideas and collaborations by providing an overview of: 1) the current improvements in our scattering laboratory methodology, 2) introducing our open, modular robotic platform that is used for systematic sample preparation, and 3) demonstrating the data structure of the synthesis logs and measurements. Finally, the remaining bottlenecks and points of attention across all three are highlighted.
T2 - FAIRmat seminar
CY - Berlin, Germany
DA - 28.09.2023
KW - Data stewartship
KW - Metadata collection
KW - Laboratory methodology
KW - MOUSE
KW - Robotics
KW - Lab automation
KW - Holistic science
PY - 2023
UR - https://www.fairmat-nfdi.eu/events/brian-pauw
AN - OPUS4-58464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - Chasing perfection: A holistic approach to materials science scattering experiments
N2 - The materials scientists we work with do not want (or need) to learn the ways of the scatterer; they are primarily interested in obtaining trustworthy answers. In particular, they need structural understanding in light of the wider framework of their experiment(s). Our interest, therefore, lies in helping them attain this this interconnected understanding, while using such investigations to further hone our methodology to approximate perfection.
While perfection is by definition an unattainable goal, we have spent the last 15+ years exploring and expanding on many of its constituent aspects (often together with likeminded people) [1]. These aspects include:
- developing various visualization and simulation tools,
- deconstructing data corrections and uncertainty estimation,
- advancing analysis methods,
- quantifying questions on traceability, documentation,
- reproducible automation of synthesis-, measurement- and data pipelines,
- data visualization, exploration and education,
- and many more…
T2 - XIX International Small Angle Scattering Conference
CY - Taipei, Taiwan
DA - 04.11.2024
KW - Methodology
KW - X-ray scattering
KW - Data quality
KW - Data provenance
KW - Data stewardship
KW - Lab automation
KW - Perfection
PY - 2024
AN - OPUS4-61625
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - DACHS/MOFs/AutoMOFs_2/Synthesis
N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters.
DACHS_MOFs is simultaneously used to test the DACHS principles.
This upload contain synthesis data from AutoMOFs_2 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample.
KW - Automation
KW - Procedure
KW - Synthesis
KW - Traceability
PY - 2024
DO - https://doi.org/10.5281/zenodo.11236074
PB - Zenodo
CY - Geneva
AN - OPUS4-60611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - A holistic experiment chain for scattering-powered materials science investigations
N2 - In our (dramatically understaffed) X-ray scattering laboratory, developing a systematic, holistic methodology1 let us provide scattering and diffraction information for more than 2100 samples for 200+ projects led by 120+ collaborators over the last five years. Combined with universal, automat-ed data correction pipelines, as well as our analysis and simulation software, this led to more than 40 papers2 in the last 5 years with just over 2 full-time staff members.
While this approach greatly improved the consistency of the results, the consistency of the samples and sample series provided by the users was less reliable nor necessarily reproducible. To address this issue, we built an EPICS-controlled, modular synthesis platform to add to our laboratory. To date, this has prepared over 1200 additional (Metal-Organic Framework) samples for us to meas-ure, analyse and catalogue. By virtue of the automation, the synthesis of these samples is automat-ically documented in excruciating detail, preparing them for upload and exploitation in large-scale materials databases alongside the morphological results obtained from the automated X-ray scat-tering analysis.
Having developed these proof-of-concepts, we find that the consistency of results are greatly im-proved by virtue of their reproducibility, hopefully adding to the reliability of the scientific findings as well. Additionally, the nature of the experiments has changed greatly, with much more emphasis on preparation and careful planning. This talk will discuss the advantages and disadvantages of this highly integrated approach and will touch upon upcoming developments.
T2 - canSAS-XIII
CY - Grenoble, France
DA - 16.10.2023
KW - Methodology
KW - Lab automation
KW - X-ray scattering
KW - Automated synthesis
KW - Data stewardship
KW - Holistic experimental procedures
KW - Scicat
PY - 2023
AN - OPUS4-58643
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - High Tm poly(L-lactide)s via REP or ROPPOC of L-lactide
N2 - A new kind of high melting (HTm) pol(L-lactide) was discovered when cyclic poly(L-lactide)s were prepared by ring-expansion polymerization with cyclic tin catalysts at 130–160 °C in bulk. By DSC measurements with 10 K min−1 melting temperatures (Tm) in the range of 190–196 °C were found. The WAXS and SAXS measurements evidenced that not a new crystal lattice but a well-ordered morphology and a higher perfection of the crystallites are responsible for the high Tm values and high crystallinities. Under identical reaction conditions SnOct2-catalyzed and alcohol-initiated ROPs do not yield these crystallites.
Furthermore, it was found that the standard crystallites are kinetically favored upon rapid crystallization, whereas the high melting form of poly(L-lactide) is thermodynamically more stable.
KW - Polylactide
KW - MALDI-TOF MS
KW - ROPPOC
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507477
DO - https://doi.org/10.1039/c9py01908a
VL - 11
IS - 12
SP - 2182
EP - 2193
PB - Royal Society of Chemistry
AN - OPUS4-50747
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Chatti, S.
A1 - Kricheldorf, H. R.
T1 - About the transformation of low Tm into high Tm poly(L-lactide)s by annealing under the influence of transesterification catalysts
N2 - Cyclic polylactides were prepared in bulk at 170 °C, crystallized at 120 °C and then annealed at temperatures between 130 and 170 C with variation of catalyst, catalyst concentration and annealing time. The transformation of the initially formed low melting (LTm) crystallites, having melting temperatures (Tm) <180 °C into high melting (HTm) crystallites having Tm values > 189 °C was monitored by means of DSC measurements and characterized in selected cases by SAXS measurements. It was confirmed that the formation of HTm crystallites involves a significant growth of the thickness of the lamellar crystallites along with smoothing of their surface. Annealing at 170 °C for 1 d or longer causes thermal degradation with lowering of the molecular weights, a gradual transition of cyclic into linear chains and a moderate decrease of lamellar thickness. An unexpected result revealed by MALDI TOF mass spectrometry is a partial reorganization of the molecular weight distribution driven by a gain of crystallization enthalpy.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystallization
KW - Annealing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521062
DO - https://doi.org/10.1039/d0ra10012a
VL - 11
IS - 5
SP - 2872
EP - 2883
PB - Royal Society of Chemistry
AN - OPUS4-52106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Polymerization of L-lactide with SnCl2: A Low Toxic and Eco-friendly Catalyst
N2 - Polymerizations of L-lactide catalyzed either by neat SnCl2 or by SnCl2 + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/Cat ratio and time. With neat SnCl2 poly(L-lactide) having weight average molecular weights (uncorrected Mw’s) up to 190 000 g mol−1 were obtained mainly consisting of linear chains. Addition of salicylic acid or 1,1-bisphenol yielded a higher fraction of cyclic polylactides but lower molecular weights. Furthermore, SnCl2 was compared with Bu2SnCl2 and various other metal chlorides and the best results were obtained with SnCl2. With ethyl L-lactate as initiator SnCl2-catalyzed ROPs were performed at 120 °C and the lac/initiator ratio was varied. All these experiments were conducted under conditions allowing for comparison with ROPs catalyzed with neat Sn(II)-2-ethyhexanoate. Such a comparison was also performed with ε-caprolactone as monomer.
KW - Catalyst
KW - Polylactide
KW - MALDI-TOF MS
KW - Polycondensation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520517
DO - https://doi.org/10.1007/s10924-020-02042-w
SN - 1566-2543
SP - 1
EP - 13
PB - Springer Nature
AN - OPUS4-52051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - High molecular weight poly(l-lactide) via ring-opening polymerization with bismuth subsalicylate-The role of cocatalysts
N2 - The catalytic potential of bismuth subsalicylate (BiSub), a commercial drug, for ring-opening polymerization (ROP) of L-lactide was explored by variation of co-catalyst and polymerization time. Various monofunctional phenols or carboxylic acids, aromatic ortho-hydroxy acids and diphenols were examined as potential co-catalysts. 2,2´-Dihydroxybiphenyl proved to be the most successful co-catalyst yielding weight average molecular weights (uncorrected Mw values up to 185 000) after optimization of reaction time and temperature. Prolonged heating (>1-2h) depending on catalyst concentration) caused thermal degradation. In polymerization experiments with various commercial Bi(III) salts a better alternative to BiSub was not found. By means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry a couple of unusual and unexpected transesterification reactions were discovered. Finally, the effectiveness of several antioxidants and potential catalyst poisons was explored, and triphenylphosphine was found to be an effective catalyst poison.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-opening polymerization
KW - Bismuth
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519513
DO - https://doi.org/10.1002/app.50394
SN - 0021-8995
VL - 138
IS - 19
SP - 50394
PB - Wiley
AN - OPUS4-51951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - ROP of L-lactide and ε-caprolactone catalyzed by tin(ii) and tin(iv) acetates–switching from COOH terminated linear chains to cycles
N2 - The catalytic potential of tin(II)acetate, tin(IV)acetate, dibutyltin-bis-acetate and dioctyl tin-bis-acetate was compared based on polymerizations of L-lactide conducted in bulk at 160 or 130C. With SnAc2 low-Lac/Cat ratios (15/1–50/1) were studied and linear chains having one acetate and one carboxyl end group almost free of cyclics were obtained. Higher monomer/catalyst ratios and lower temperatures favored formation of cycles that reached weight average molecular weights (Mw's) between 100,000 and 2,500,000. SnAc4 yielded mixtures of cycles and linear species under all reaction conditions. Dibutyltin- and dioctyl tin bis-acetate yielded cyclic polylactides under most reaction conditions with Mw's in the range of 20,000–80,000. Ring-opening polymerizations performed with ε-caprolactone showed similar trends, but the formation of COOH-terminated linear chains was significantly more favored compared to analogous experiments with lactide. The reactivity of the acetate catalysts decreased in the following order: SnAc2> SnAc4>Bu2SnAc2 Oct2SnAc2.
KW - Catalyst
KW - MALDI-TOF MS
KW - Ring-opening polymerization
KW - Tin acetates
KW - Polylactide
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520831
DO - https://doi.org/10.1002/pol.20200866
SP - 1
EP - 12
PB - Wiley Online Library
AN - OPUS4-52083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Kricheldorf, H. R.
A1 - Scheliga, F.
T1 - Ring-expansion copolymerization of L-lactide and glycolide
N2 - 1:1 Copolymerizations of glycolide (GL) and L-lactide (LA) is performed in bulk at 100°C and at 160°C with four cyclic tin catalysts. The resulting copolyesters are characterized by SEC measurements, 1H and 13C NMR spectroscopy and by MALDI TOF mass spectrometry. At 160°C and longer reaction time (22 h) nearly complete conversion of both monomers is achieved, and cyclic copolymers with nearly random sequences are formed. At shorter times (0.5-3.0 h, depending on catalyst) the conversion of LA is incomplete, and only cyclics having even numbers of lactyl units are obtained. At 100°C at 22 h again cycles mainly consisting of even numbered lactyl units are formed, but with even and odd numbers of glycolyl units. Copolymerization of lactide at 160°C with small amounts of GL show that formation of high Tm crystallites (Tm > 190°C) is hindered even when only > 2% of GL is added. For polyglycolide containing a smaller amount of lactide complete solubility in hexafluoroisopropanol is only observed around and above 20 mol% of lactide.
KW - Ring-expansion polymerization
KW - Copolymerization
KW - MALDI-TOF MS
KW - L-lactide
KW - Glycolide
KW - Crystallization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520270
DO - https://doi.org/10.1002/macp.202000307
SN - 1022-1352
VL - 22
IS - 3
SP - 307
PB - WileyVCH
AN - OPUS4-52027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholz, Philipp
A1 - Falkenhagen, Jana
A1 - Wachtendorf, Volker
A1 - Brüll, Robert
A1 - Simon, Franz-Georg
T1 - Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios
N2 - Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.
KW - Geotextiles
KW - Microplastic
KW - Size exclusion chromatography
KW - Accelerated aging
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599739
DO - https://doi.org/10.3390/su16093559
SN - 2071-1050
VL - 16
IS - 9
SP - 1
EP - 15
PB - MDPI AG
CY - Basel
AN - OPUS4-59973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Choi, Ching-Yi
A1 - Lossada, F.
A1 - Walter, K.
A1 - Fleck-Kunde, T.
A1 - Behrens, S.
A1 - Meinelt, T.
A1 - Falkenhagen, Jana
A1 - Hiller, M.
A1 - Oschkinat, H.
A1 - Dallmann, A.
A1 - Taden, A.
A1 - Börner, H.G.
T1 - Organic transformation of lignin into mussel-inspired glues: next-generation 2K adhesive for setting corals under saltwater
N2 - The 2-methoxyphenol units (G-units) in lignin are modified by demethylation and oxidation to provide the activated lignin as one part of an advanced biobased two-component (2K) adhesive system, which exhibits promising shear strengths in dry and underwater applications. The activation of lignin is straightforward and generates quinones via demethylation and periodate oxidation. These act as Michael acceptors and react smoothly with multi-thiol-star polymers to yield thiol-catechol connectivities (TCCs). The mussel-inspired material platform acts as a very robust and versatile adhesive, combining low-cost and readily available lignin with multi-thiols to achieve outstanding adhesion strengths of up to 15 MPa in dry application. In particular, the 2K system is compatible with the marine biological environment and shows no acute toxicity to sensitive organisms such as fish eggs. Thus, one possible application of this material could be an adhesive for setting temperature-resistant corals in damaged reefs.
KW - Lignin modification
KW - Mussel-inspired adhesive systems
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594588
DO - https://doi.org/10.1039/d3gc03680d
SN - 1463-9270
SP - 1
EP - 15
PB - RSC
CY - Cambridge
AN - OPUS4-59458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H.
T1 - Cyclic polyglycolides via ring-expansion polymerization with cyclic tin catalysts
N2 - Glycolide was polymerized in bulk with two cyclic catalysts − 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzepane (SnBiph). The monomer/initiator ratio, temperature (140 – 180 °C) and time (1–––4 days) were varied. The MALDI TOF mass spectra exclusively displayed peaks of cyclic polyglycolide (PGA) and revealed an unusual “saw-tooth pattern” in the mass range below m/z 2 500 suggesting formation of extended ring crystallites. The DSC measurements indicated increasing crystallinity with higher temperature and longer time, and after annealing for 4 d at 160 °C a hitherto unknown and unexpected glass transition was found in the temperature range of 170–185 °C. Linear PGAs prepared by means of metal alkoxides under identical conditions did not show the afore-mentioned features of the cyclic PGAs, neither in the mass spectra nor in the DSC measurements. All PGAs were also characterized by SAXS measurements, which revealed relatively small L-values suggesting formation of thin crystallites in all cases with little influence of the reaction conditions.
KW - Polyglycolide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Crystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595541
DO - https://doi.org/10.1016/j.eurpolymj.2024.112811
SN - 0014-3057
VL - 207
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-59554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Polycondensation of poly(L-lactide) alkyl esters combined with disproportionation and symproportionation of the chain lengths
N2 - Ring-opening polymerizations (ROPs) of l-lactide (LA) were performed with ethyl l-lactate or 11-bromoundecanol as initiators (In) and tin(II) ethyl hexanoate (SnOct2) as catalyst (Cat) using four different LA/In ratios (20/1, 40/1, 60/1, and 100/1). One series of ROPs was conducted in bulk at 120 °C, yielding PLAs with low dispersities (Ð ~ 1.2–1.4), and a second series was conducted in bulk at 160 °C, yielding higher dispersities (Ð ~ 1.3–1.9). Samples from both series were annealed for 1 or 14 days at 140 °C in the presence of SnOct2. Both polycondensation and disproportionation reactions occurred, so that all four samples tended to form the same type of molar mass distribution below 10,000 Da, regardless of their initially different number average molar masses (Mn). Both initiators gave nearly identical results. The thermodynamic control of all reversible transesterification processes favored the formation of crystallites composed of chains with a Mn around 3500–3700, corresponding to a crystal thickness of 10–13 nm.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600081
DO - https://doi.org/10.1002/pol.20240118
SN - 2642-4150
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-60008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Syntheses of high molecular mass polyglycolides via ring-opening polymerization with simultaneous polycondensation (ROPPOC) by means of tin and zinc catalysts
N2 - Glycolide was polymerized in bulk by means of four different ROPPOC catalysts: tin(II) 2-ethylhexanoate (SnOct2), dibutyltin bis(pentafluoro-phenoxide) (BuSnOPF),zinc biscaproate (ZnCap), and zinc bis(pentafluoro-phenyl sulfide) (ZnSPF). The temperature was varied between 110 and 180°C and the time between 3 h and 7 days. For the few polyglycolides (PGAs) that were soluble extremely high molecular masses were obtained. The MALDI TOF mass spectra had all a low signal-to-noise ration and displayed the peaks of cyclic PGAs with a“saw-tooth pattern ”indicating formation of extended-ring crystallites in the mass range below m/z 2500. The shape of DSC curves varied considerably with catalyst and reaction conditions, whereas the long-distance values measured by SAXS were small and varied little with the polymeriza-tion conditions.
KW - MALDI TOF MS
KW - Polyglycolide
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598221
DO - https://doi.org/10.1002/pat.6365
VL - 35
IS - 4
SP - 1
EP - 10
PB - John Wiley & Sons Ltd.
AN - OPUS4-59822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
T1 - Low Molar Mass Cyclic Poly(L-lactide)s: Separate Transesterification Reactions of Cycles and Linear Chains in the Solid State
N2 - L-Lactide (LA) was polymerized with neat tin(II) 2-ethylhexanoate (SnOct2) in toluene at 115 °C at low concentration with variation of the LA/Cat ratio. Cyclic polylactides (cPLAs) with number average molecular weights (Mn) between 7 000 and 17 000 were obtained. MALDI-TOF mass spectrometry also revealed the formation of a few percent of linear chains. Crystalline cPLAs with Mn around 9 000 and 14 000 were annealed at 140 °C in the presence of ScOct2 or dibutyl-2-stanna-1,3-dithiolane (DSTL). Simultaneously, crystallites of extended linear chains and crystallites of extended cycles were formed regardless of the catalyst, indicating that transesterification reaction proceeded different for linear chains and for cycles, governed by thermodynamic control. The formation of extended chain crystallites with low dispersity indicates the existence of symproportionation of short and long chains. A complementary experiment was carried out with a PLA ethyl ester composed mainly of linear chains with a small fraction of cycles
KW - Polylactide
KW - MALDI-TOF MS
KW - Annealing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606228
DO - https://doi.org/10.1039/D4SM00567H
SN - 1744-6848
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cherbib, S.
A1 - Jlalia, I.
A1 - Chabbah, T.
A1 - Chatti, S.
A1 - Marestin, C.
A1 - Mercier, R.
A1 - Weidner, Steffen
A1 - Casabianca, H.
A1 - Jaffrezic-Renault, N.
A1 - Abderrazak, H.
T1 - Design of New Partially Bio-Based Polyguanamines for the Reversible Adsorption of Phenolic Molecules from Olive Mill Wastes
N2 - Olive mill wastewater produces a variety of potent antioxidants, including hydroxytyrosol, oleuropein, and tyrosol, that have been widely used in agriculture, pharmacy, and cosmetics. This study aims to design new poly(guanamine)s phases by polycondensation of modified triazine monomers with both petro-based and biosourced diamines, to act as stationary phases for the uptake of these phenolic molecules. Obtained polymers were characterized by NMR spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The adsorption results showed that the newly synthesized polymers can effectively uptake the less polar phenolic compounds, ferulic acid, and caffeic acid. The isosorbide-based polymer (P6) presented the highest sorption efficiency, due to the hydrophilic properties of isosorbide associated with the proton affinity of the triazine groups. All the phenolic compounds were successfully desorbed from the P6 polymer using a minimal amount of a methanol/acetonitrile mixture. P6 polymer could be used for four successive adsorption processes without loss of efficiency.
KW - Olive mill wastewater
KW - Triazine
KW - Isosorbide
KW - Adsorption
KW - Phenolic compounds
PY - 2024
DO - https://doi.org/10.1007/s42250-024-01081-3
SN - 2522-5758
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61348
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - SnOct2-catalyzed and alcohol-initiated ROPS of L-lactide - Control of the molecular weight and the role of cyclization
N2 - Ring-opening polymerizations (ROP) of l-lactide (LA) are conducted in bulk at 130, 160, or 180 °C and are initiated with two different alcohols at 160 °C. The lactide/initiator ratio (LA/In) is varied from 50/1 (20/1 at 180 °C) to 900/1 and the lactide/catalyst ratio (LA/Cat) between 2000/1 and 8000/1. At all temperatures a nearly perfect control of number average molecular weight (Mn) via the LA/In ratio is feasible up to LA/In = 200/1, but at higher ratios the Mn value lags behind the theoretical values and the discrepancy increases with higher LA/Cat ratios. Variation of the LA/Cat ratio influences the formation of cycles but does not significantly influence Mn, when the LA/In ratio is kept constant. The formation of cycles is favored by lower In/Cat ratios and is the main reason for the unsatisfactory control of Mn at high LA/In ratios. The results also suggest that the cycles are mainly or exclusively formed by end-to-end cyclization and not, as believed previously, by back-biting.
KW - Polylactide
KW - MALDI-TOF MS
KW - Cyclization
KW - Ring-opening polymerization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543066
DO - https://doi.org/10.1002/macp.202100464
SN - 1521-3935
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Syntheses of Polyglycolide via Polycondensation: A Reinvestigation
N2 - The Na salt of chloroacetic acid is condensed in suspension. Furthermore,glycolic acid is condensed in bulk or in concentrated solution by means of SnCl2 or 4-toluene sulfonic acid (TSA) as catalysts. The temperatures are varied from 160 to 200°C and the time from 1 to 5 days. Low molar mass cyclic poly(glycolic acid) (PGA) is detected by means of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry in most PGAs. A predominance of certain cycles having an even number of repeat units is observed suggesting a thermodynamically favored formation of extended-ring crystals. Extremely high melting temperatures (up to 237.5°C)and high melting enthalpies are found for polycondensations with TSA in 1,2-dichlorobenzene.
KW - MALDI TOF MS
KW - Polycondensation
KW - Polyglycolide
KW - Cyclization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596856
DO - https://doi.org/10.1002/macp.202300397
IS - 2300397
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-59685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Roland
A1 - Scholz, Philipp
A1 - Jung, Christian
A1 - Weidner, Steffen
T1 - Thermo-Desorption Gas Chromatography-Mass Spectrometry for investigating the thermal degradation of polyurethanes
N2 - Thermo-Desorption Gas Chromatography-Mass Spectrometry (TD-GC-MS) was used to investigate the thermal degradation of two different polyurethanes (PU). PU samples were heated at different heating rates and the desorbed products were collected in a cold injection system and thereafter submitted to GC-MS. Prospects and limitations of the detection and quantification of semi-volatile degradation products were investigated. A temperature dependent PU depolymerization was
found at temperatures above 200 °C proved by an increasing release of 1,4-butanediol and methylene diphenyl diisocyanate (MDI) representing the main building blocks of both polymers. Their release was monitored quantitatively based on external calibration with authentic compounds. Size Exclusion Chromatography (SEC) of the residues obtained after thermodesorption confirmed the initial competitive degradation mechanism indicating an equilibrium of crosslinking and depolymerization as previously suggested. Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry of SEC fractions of thermally degraded PUs provided additional hints on degradation mechanism.
KW - Thermo-desorption
KW - Mass spectrometry
KW - Polyurethanes
KW - Thermal degradation
PY - 2023
DO - https://doi.org/10.1039/D3AY00173C
SN - 1759-9660
SP - 1
EP - 6
PB - Royal Society for Chemistry
AN - OPUS4-57307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Synthesis of polylactides by means of tin catalysts
N2 - This article reviews the usefulness of tin(II) and tin(IV) salts and compounds as catalysts for the polymerization of lactides. The text is subdivided into nine parts mainly reflecting different polymerization strategies, such as ring-opening polymerization (ROP), ring-expansion polymerization (REP), ROP combined with simultaneous polycondensation (ROPPOC), various catalysts with unknown polymerization mechanisms, and polycondensation of lactic acid. Since the toxicity of tin salts and compounds is a matter of concern and frequently mentioned in numerous publications, the first section deals with facts instead of myths about the toxicity of tin salts and compounds.
KW - Polylactide
KW - MALDI-TOF MS
KW - Tin catalysts
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545050
DO - https://doi.org/10.1039/d2py00092j
SP - 1
EP - 30
PB - Royal Society for Chemistry
AN - OPUS4-54505
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
T1 - Ring-ring equilibration (RRE) of cyclic poly(L-lactide)s by means of cyclic tin catalysts
N2 - With 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzoxepane (SnBiPh) as catalysts ring-expansion polymerizations (REP) were performed either in 2 M solution using three different solvents and two different temperatures or in bulk at 140 and 120 ◦C. A kinetically controlled rapid REP up to weight average molecular masses (Mẃs) above 300 000 was followed by a slower degradation of the molecular masses at 140 ◦C, but not at 120 ◦C Furthermore, a low molecular mass cyclic poly(L-lactide) (cPLA) with a Mn around 16 000 was prepared by polymerization in dilute solution and used as starting material for ring-ring equilibration at 140 ◦C in 2 M solutions. Again, a decrease of the molecular mass was detectable, suggesting that the equilibrium Mn is below 5 000. The degradation of the molecular masses via RRE was surprisingly more effective in solid cyclic PLA than in solution, and a specific transesterification mechanism involving loops on the surface of crystallites is proposed. This degradation favored the formation of extended-ring crystallites, which were detectable by a “saw-tooth pattern” in their MALDI mass spectra.
KW - Organic Chemistry
KW - Polymers and Plastics
KW - MALDI-TOF MS
KW - Materials Chemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593819
DO - https://doi.org/10.1016/j.eurpolymj.2024.112765
SN - 0014-3057
VL - 206
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-59381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Scheliga, F.
A1 - Weidner, Steffen
T1 - Syntheses of Cyclic Poly(l-lactide)s by Means of Zinc-Based Ring-Opening Polymerization with Simultaneous Polycondensation (ROPPOC) Catalysts
N2 - Ring-opening polymerizations of l-lactide are studied in bulk at 140 or 160 °C with zinc n-hexanoate, zinc 4-chlorothiophenolate, and zinc pentafluoro thiophenolate (ZnSPF) as catalysts. The reactivity increases in the given order.
With all three catalysts a high fraction of cycles is obtained only at polymerization (annealing) times around 7 d. With ZnSPF weight average molecular weights (Mw) up to 178 000, a Tm around 199 °C and a 𝚫Hm around 99 J g−1 were achieved. The samples annealed for 4 or 7 d also display a saw tooth pattern of the mass peak distribution in the matrix-assisted laser desorption/ionization time of flight spectra indicating transesterification reactions across the surface of extended ring crystals. This process optimizes the thermodynamical properties of the crystalline cyclic polylactides and is responsible for the high Tm and 𝚫Hm values.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring opening polymerization
KW - Polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578264
DO - https://doi.org/10.1002/macp.202300070
SN - 1022-1352
SP - 202300070
PB - Wiley VHC-Verlag
AN - OPUS4-57826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Ring-opening polymerizations of L-Lactide catalyzed by zinc caprylate: Syntheses of cyclic and linear poly(L-lactide)s
N2 - Alcohol-initiated ring-opening polymerizations (ROPs) of L-Lactide (LA) were conducted in bulk at 130 °C catalyzed by Zn acetate (ZnAc2), lactate (ZnLac2), or caprylate (ZnCap2). 11-undecenol (UND), 1-hydroxymethylnaphtalene (HMN), and 4-nitrobenzylalcohol (4NB) were used as alcohols. Whereas variation of the alcohols had little effect, the usefulness of the catalysts increased in the order: acetate < lactate < caprylate. Hence, further alcohol-initiated polymerizations were performed with ZnCap2 alone and with variation of the lactide/catalyst (LA/Cat) ratio. With increasing LA/Cat ratio higher fractions of cyclic poly(L-lactide) (PLA) were found, so that the measured degree of polymerization (DP) is considerably lower than the theoretical value (i.e., 2 x LA/alcohol). With neat ZnCap2 cyclic PLAs were the largely prevailing reaction products. For these cyclic PLAs weight average molar masses (Mw) up to 134,000 were obtained and an optical purity around 99% was indicated by 13C NMR spectroscopy and DSC measurements even after 48 h at 150 or 160 °C.
KW - Cyclization
KW - Lactide
KW - Ring opening polymerization
KW - Transesterification
KW - Zinc catalyst
KW - MALDI
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557565
DO - https://doi.org/10.1002/pol.20220328
SN - 2642-4150
SP - 1
EP - 10
PB - Wiley
AN - OPUS4-55756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
T1 - Cyclic and linear poly(L-lactide)s by ring-expansion polymerization with Bu2SnO, Oct2SnO, and Bu2SnS
N2 - To elucidate the usefulness of commercial Bu2SnO as catalyst for syntheses of linear and/or cyclic polylactides L-Lactide was polymerized in bulk with variation of the LA/Cat ratio, temperature and time. Based on a ring-expansion polymerization (REP) mechanism cyclic polylactides (PLAs) with weight average molecular weights in the range of 200,000–300,000 are obtained at the highest temperature (180 °C). Polymerizations at 150 °C yielded crystalline, mainly cyclic polylactides which, after annealing, showed high melting temperatures (up to 197.5 °C) and high crystallinities (>80%). Polymerization at 120 °C confirmed the trend towards more linear chains with lower temperatures but yielded extended-ring crystals showing a “saw-tooth pattern” in the mass spectra. Oct2SnO gave similar results as Bu2SnO. Bu2SnS proved a sluggish polymerization catalyst, but a good transesterification catalyst in solid PLA.
KW - MALDI TOF MS
KW - Biobased polymers
KW - Polylactide
KW - Ring-expansion polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584121
DO - https://doi.org/10.1002/pol.20230515
SN - 2642-4169
SP - 1
EP - 10
PB - Wiley
CY - Hoboken, NJ
AN - OPUS4-58412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About the Influence of (Non-)Solvents on the Ring Expansion Polymerization of l-Lactide and the Formation of Extended Ring Crystals
N2 - Ring-expansion polymerizations (REPs) catalyzed by two cyclic tin catalysts (2-stanna-1.3-dioxa-4,5,6,7-dibenzazepine [SnBiph] and
2,2-dibutyl-2-stanna-1,3-dithiolane [DSTL]) are performed at 140 °C in bulk.
Small amounts (4 vol%) of chlorobenzene or other solvents are added to
facilitate transesterification reactions (ring–ring equilibration) in the solid poly(l-lactide)s. In the mass range up to m/z 13 000 crystalline PLAs displaying a so-called saw-tooth pattern in the MALDI-TOF mass spectra are obtained indicating the formation of extended-ring crystals. The characteristics of extended-ring crystallites and folded-ring crystallites are discussed. Furthermore, extremely high melting temperatures (Tm’s up to 201.2 °C) and melting enthalpies (𝚫Hm’s up to 106 J g−1)) are found confirming that 𝚫Hm max, the 𝚫Hm of a perfect crystal, is around or above 115 J g−1 in contrast to literature data.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Biobased
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573063
DO - https://doi.org/10.1002/macp.202200385
VL - 224
IS - 5
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-57306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geburtig, Anja
A1 - Wachtendorf, Volker
A1 - Falkenhagen, Jana
T1 - Combined impact of UV radiation and nitric acid on high‐density polyethylene containers as a laboratory test
N2 - In a laboratory test, transparent high‐density polyethylene (HDPE) jerrycans have been exposed to both UV radiation and 55 wt‐% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The damages are compared with FTIR spectroscopy in ATR and HT‐gel permeation chromatography(GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. This is caused by the decomposition of nitric acid into nitrous gases by UV radiation, which is also observed at lower concentrations (28 wt‐%). After 6 days of laboratory exposure, this is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. The gradual increase in oxidative damage shows the reproducibility of the test.
KW - Molecular mass distribution
KW - High-density polyethylene
KW - Nitric acid
KW - UV radiation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550141
DO - https://doi.org/10.1002/pts.2673
SN - 0894-3214
VL - 35
IS - 10
SP - 729
EP - 735
PB - Wiley
CY - New York, NY
AN - OPUS4-55014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, Andreas
A1 - Weidner, Steffen
A1 - Kricheldorf, Hans R.
T1 - Star-shaped poly(l-lactide)s based on pentaerythritol: About crystallization and polycondensation plus disproportionation and ring formation in the solid state
N2 - Star-shaped poly( L-lactide)s (s-PLAs), were prepared by ring-opening polymerization of with pentaerythritol and catalyzed by tin(II) 2-ethylhyexanoate (SnOct out in bulk at either 120 ◦ C or 160 ◦ L-lactide (LA) initiated 2 ). Two small series of ROPs were carried C with variation of the LA/initiator ratio. Matrix-assisted laser desorption/ ionization time-of-flight (MALDI-TOF) mass spectra revealed traces of cycles in 120 ◦ C samples only at low initiator/catalyst ratios. In contrast, higher fractions of cycles were detected in samples prepared at 160 C, suggesting a "back-biting" origin. The influence of arm length and thermal history on crystallinity was investigated by differential scanning calorimetry (DSC) and wide-angle x-ray scattering (WAXS). It was shown that annealing increased the melting temperature (T ◦ ◦ m ) and crystallinity. However, annealing at 140 ◦ C for 14 d also caused significant solid-state transesterification. In addition, crystallites composed of s-PLAs with extended arms and, simultaneously, crystallites composed exclusively of extended rings were formed, identified by their typical "sawtooth" pattern in the MALDI mass spectra. Small angle x-ray scattering (SAXS) indicated that the crystal thickness was lower than that of linear PLAs annealed under identical conditions, but increased upon annealing at 140 C.
KW - MALDI-TOF MS
KW - Polylactide
KW - Crystallisation
KW - AStar-shaped polymers
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636832
DO - https://doi.org/10.1016/j.polymer.2025.128709
SN - 0032-3861
VL - 334
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
T1 - Zwitterionic polymerization of glycolide catalyzed by pyridine
N2 - The usefulness of various N- and P-based catalysts for syntheses of cyclic polyglycolide via zwitterionic polymerization of glycolide was examined. Most catalysts produced discolored, largely insoluble polyglycolides consisting of cycles and unidentified byproducts. Soluble, cyclic polyglycolides were obtained using neat pyridine as catalyst at 120 °C, 100 °C, 80 °C, and even at 60 °C. The number-average molecular weights were extremely low and depended slightly on the glycolide-to-pyridine ratio. Three different mass distributions of the cycles were detected by mass spectrometry, depending on the reaction conditions. The cyclic polyglycolides were also characterized by differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) measurements. The SAXS data in combination with the mass spectra indicate that the majority of the cycles form extended-ring crystallites
KW - MALDI-TOF MS
KW - Polylactide
KW - Polymerization
KW - Zitterions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639748
DO - https://doi.org/10.1039/d5py00762c
SN - 1759-9954
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63974
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bui, Minh
A1 - Heinekamp, Christian
A1 - Fuhry, Emil
A1 - Weidner, Steffen
A1 - Radnik, Jörg
A1 - Ahrens, Mike
A1 - Scheurell, Kerstin
A1 - Balasubramanian, Kannan
A1 - Emmerling, Franziska
A1 - Braun, Thomas
T1 - Lewis-acid induced mechanochemical degradation of polyvinylidene fluoride: transformation into valuable products
N2 - Polyvinylidene fluoride (–[CH2CF2]n–, PVDF) waste poses significant environmental challenges due to its recalcitrant nature and widespread use. This study addresses the end-of-life management of PVDF by introducing a novel, sustainable mechanochemical approach for its valorisation. We investigated the degradation of PVDF into value-added materials using ball milling with anhydrous AlCl3 to achieve a quantitative mineralisation producing AlF3 and halide-functionalised graphite, along with gaseous products (HCl and CH4). Mechanistic key steps involve Lewis-acid catalysed C–F bond activation, dehydrofluorination and aromatisation. This approach provides an effective solution for PVDF waste management while offering a promising route for the production of high-value materials from polymer waste streams. Our findings contribute to sustainable practices in polymer recycling and resource recovery, respond to pressing environmental concerns associated with fluoropolymer disposal, and demonstrate the potential to convert polymer wastes into useful products.
KW - Mechanochemistry
KW - Polyvinylidenfluoride
KW - Degradation
KW - Ball mill
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649015
DO - https://doi.org/10.1039/d5sc05783c
SN - 2041-6520
VL - 16
IS - 40
SP - 18903
EP - 18910
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About Polycondensation, Disproportionation, and Cyclization of Acetylated Poly(L-Lactide) Esters
N2 - L-lactide (LA) is polymerized with ethyl L-lactate or trifluoroethanol as initiators (LA/In = 30/1), and the resulting poly(L-lactide) esters are acetylated with acetic anhydride. The acetylated PLA esters are mixed with SnOct2, dibutyltin bis(4-chlorophenoxide), or dibutyltin bis(pentafluorophenoxide) in solution and crystallized at 120 °C. The doped crystals are annealed at 140 °C or at 160 °C for 7, 14, and 28 days, and the chemical modifications that occurred in the solid state are monitored by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) measurements. All catalysts promoted polycondensation, while no significant formation of cycles is observed. However, in the presence of SnOct2, disproportionation of chains occurred upon annealing at 120 or 140 °C, and crystallites consisting of extended chains with Mn values ≈3500 – 3600 and low dispersities (Ð < 1.5) are formed.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Polylactides
KW - Transesterifcation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630349
DO - https://doi.org/10.1002/macp.202400175
SN - 1521-3935
VL - 225
IS - 19
PB - Wiley VHC-Verlag
AN - OPUS4-63034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Schwab, Alexander
A1 - Carraro, Francesco
A1 - Tavernaro, Isabella
A1 - Falkenhagen, Jana
A1 - Villajos, Jose
A1 - Falcaro, Paolo
A1 - Emmerling, Franziska
T1 - ZIF-8-based biocomposites via reactive extrusion: towards industrial-scale manufacturing
N2 - Mechanochemistry, a sustainable synthetic method that minimizes solvent use, has shown great promise in producing metal–organic framework (MOF)-based biocomposites through ball milling. While ball milling offers fast reaction times, biocompatible conditions, and access to previously unattainable biocomposites, it is a batch-type process typically limited to gram-scale production, which is insufficient to meet commercial capacity. We introduce a scalable approach for the continuous solid-state production of MOF-based biocomposites. Our study commences with model batch reactions to examine the encapsulation of various biomolecules into Zeolitic Imidazolate Framework-8 (ZIF-8) via hand mixing, establishing a foundation for upscaling. Subsequently, the process is scaled up using reactive extrusion, enabling continuous and reproducible kilogram-scale production of bovine serum albumin (BSA)@ZIF-8 with tunable protein loading. Furthermore, we achieve the one-step formation of shaped ZIF-8 extrudates encapsulating clinical therapeutic hyaluronic acid (HA). Upon release of HA from the composite, the molecular weight of HA is preserved, highlighting the industrial potential of reactive extrusion for the cost-effective and reliable manufacturing of biocomposites for drug-delivery applications.
KW - Mechanochemistry
KW - Extrusion
KW - Biocompoites
KW - MOFs
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654777
DO - https://doi.org/10.1039/D5TA08276E
SN - 2050-7496
SP - 1
EP - 14
PB - Royal Society of Chemistry
AN - OPUS4-65477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, Andreas
T1 - Poly(butylene terephthalate): About condensation, cyclization, degradation and elimination reactions in the solid state, and the role of smooth crystal surfaces
N2 - Three commercial poly(butylene terephthalate) (PBT) samples - Pocan B1300 (B13), Pocan B1600 (B16), and Addigy P 1210 (AP121) - served as the starting materials for the annealing experiments, which were conducted with and without the addition of esterification and transesterification catalysts. The catalysts used were Sn(II) 2-ethylhexanoate (SnOct₂), Zr(IV) acetylacetonate, and 4-toluene sulfonic acid (TSA). Temperatures varied between 150 and 210 °C. The PBT samples were characterized using differential scanning calorimetry (DSC), gel permeation chromatography (GPC), small-angle X-ray scattering (SAXS), and matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry. The MALDI mass spectra of all three samples differed greatly but displayed mass peaks of cycles. Similar results were produced by annealing with SnOct₂ or Zr(acac)₄, which favored the formation of even-numbered cycles within the mass range below m/z 5000, along with slow degradation. TSA favored a more intensive degradation without the formation of cycles or even with the destruction of cycles. PBT chains with two carboxylic (COOH) end groups were the most stable species under all circumstances. The origin of the extremely high melting point of AP121 (241–242 °C) can be explained by the smoothing of crystallite surfaces via transesterification. The results suggest that combining MALDI mass spectrometry and SAXS measurements provides a new way to better understand the solid-state chemistry of PBT and related polyesters.
KW - MALDI-TOF MS
KW - Polybutylene Terephthalate
KW - Crystallization
KW - solid state
KW - cyclization
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652844
DO - https://doi.org/10.1016/j.polymdegradstab.2025.111862
SN - 0141-3910
VL - 245
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-65284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, Andreas
A1 - Falkenhagen, Jana
A1 - Kricheldorf, Hans R.
T1 - Cyclic polyglycolide by means of metal acetylacetonates
N2 - Glycolide was polymerized in bulk at 160 °C using various metal acetylacetonates as catalysts. Zirconium acetylacetonate was particularly efficient, enabling rapid polymerization even at 130 °C. The formation of cyclic poly(glycolic acid) (PGA), most likely via a ring-expansion polymerization (REP) mechanism, was proven by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Depending on the polymerization conditions, the formation of even-numbered cycles was favored to varying degrees. Number-average molecular weights (Mn) in the range of 2000–3500 g mol−1 were achieved with dispersities below 2.0. Wide-angle X-ray scattering (WAXS) powder patterns showed that the crystal lattice was the same as that of known linear PGAs, regardless of the Mn values. These patterns enabled a comparison of crystallinities with values derived from DSC measurements.
KW - MALDI-TOF MS
KW - Polyglycolide
KW - Crystallization
KW - Small-angle X-ray scattering
KW - Cyclization
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653731
DO - https://doi.org/10.1039/d5ra07961f
SN - 2046-2069
VL - 16
IS - 2
SP - 1757
EP - 1764
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zou, T.
A1 - Nonappa, N.
A1 - Khavani, M.
A1 - Vuorte, M.
A1 - Penttilä, P.
A1 - Zitting, A.
A1 - Valle-Delgado, J. J.
A1 - Elert, Anna Maria
A1 - Silbernagl, Dorothee
A1 - Balakshin, M.
A1 - Sammalkorpi, M.
A1 - Österberg, M.
T1 - Experimental and Simulation Study of the Solvent Effects on the Intrinsic Properties of Spherical Lignin Nanoparticles
N2 - Spherical lignin nanoparticles (LNPs) fabricated via nanoprecipitation of dissolved lignin are among the most attractive biomass-derived nanomaterials. Despite various studies exploring the methods to improve the uniformity of LNPs or seeking more application opportunities for LNPs, little attention has been given to the fundamental aspects of the solvent effects on the intrinsic properties of LNPs. In this study, we employed a variety of experimental techniques and molecular dynamics (MD) simulations to investigate the solvent effects on the intrinsic properties of LNPs. The LNPs were prepared from softwood Kraft lignin (SKL) using the binary solvents of aqueous acetone or aqueous tetrahydrofuran (THF) via nanoprecipitation. The internal morphology, porosity, and mechanical properties of the LNPs were analyzed with electron tomography (ET), small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and intermodulation AFM (ImAFM). We found that aqueous acetone resulted in smaller LNPs with higher uniformity compared to aqueous THF, mainly ascribing to stronger solvent−lignin interactions as suggested by MD simulation results and confirmed with aqueous 1,4-dioxane (DXN) and aqueous dimethyl sulfoxide (DMSO).
More importantly, we report that both LNPs were compact particles with relatively homogeneous density distribution and very low porosity in the internal structure. The stiffness of the particles was independent of the size, and the Young’s modulus was in the range of 0.3−4 GPa. Overall, the fundamental understandings of LNPs gained in this study are essential for the design of LNPs with optimal performance in applications.
KW - Lignin
KW - Electron tomography
KW - Intermodulation AFM
KW - Modulus
KW - SAXS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546948
DO - https://doi.org/10.1021/acs.jpcb.1c05319
SN - 1520-5207
VL - 125
IS - 44
SP - 12315
EP - 12328
PB - ACS
AN - OPUS4-54694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schutter, Jan David
A1 - Eberhardt, Karl
A1 - Elert, Anna Maria
A1 - Radnik, Jörg
A1 - Geißler, Daniel
A1 - Özcan Sandikcioglu, Özlem
T1 - Synthesis and characterization of lipopolysaccharide (LPS) anchored polystyrene microparticles as a synthetic model system for attachment studies
N2 - Outer membrane lipopolysaccharides (LPS) play a crucial role in determining attachment behavior and pathogenicity of bacteria. The aim of this study was to develop a simple procedure for anchoring bacterial lipopolysaccharides to polystyrene (PS) microparticles as a model system for in situ attachment studies. By using a swellcapture methodology, commercially available LPS of Pseudomonas aeruginosa (strain ATCC 27316 serotype 10.22) was anchored onto PS microparticles in a proof-of-concept study. A detailed chemical and morphological characterization has proven the success of LPS incorporation. It was shown that the coverage and structure of the LPS film was concentration dependent. The procedure can easily be adapted to LPS of other bacterial strains to generate a synthetic model toolkit for attachment studies.
KW - Bacterial lipopolysaccharides
KW - Pseudomonas aeruginosa
KW - Polystyrene microparticles
KW - Swell-capture
KW - Biomimicry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579818
DO - https://doi.org/10.1016/j.colsurfb.2023.113301
SN - 0927-7765
VL - 226
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-57981
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gawek, Marcel
A1 - Szymoniak, Paulina
A1 - Hülagü, Deniz
A1 - Hertwig, Andreas
A1 - Schönhals, Andreas
T1 - Molecular Mobility of Thin Films and the Adsorbed Layer of Poly(2-vinylpyridine)
N2 - The molecular dynamics of thin films and the adsorbed layer of poly(2-vinylpyridine) (P2VP) were investigated using broadband dielectric spectroscopy (BDS) and spectroscopic ellipsometry. Thin films of P2VP were prepared on silicon substrates and characterized to understand the influence of film thickness on the thermal glass transition temperature (Tg) and molecular mobility. The ellipsometric study revealed a decrease in Tg with decreasing film thickness, attributed to the enhanced mobility at the polymer/air interface. The adsorbed layer, prepared via the solvent leaching approach, exhibited a higher Tg compared to the bulk, indicating reduced molecular mobility due to strong polymer substrate interactions. The dielectric measurements were carried out in two different electrode configurations, crossed electrode capacitors (CEC) and nanostructured electrodes (NSE), where the latter allows for a free surface layer at the polymer/air interface. The relaxation rates of the α-relaxation measured in the CEC geometry collapse into one chart independent from the film thickness. For the thin films measured in the NSE arrangement the relaxation rates slow down with decreasing film thickness which was discussed as related to a stronger interaction of the P2VP segments with the native SiO2 at the surface of the silicon substrate compared to aluminum. It is worth to note that the effect of the enhanced mobility at the polymer/air interface is not observed in the dielectric measurements. BDS measurements in NSE geometry identified an additional relaxation process (α*-relaxation) in thin films, which was more pronounced in the adsorbed layer. This process is hypothesized to be related to molecular fluctuations within the adsorbed layer including the adsorption/desorption dynamics of segments or to a Slow Arrhenius Process (SAP) related to the equilibration dynamics deep in the glassy state.
KW - Thin polymer films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637181
DO - https://doi.org/10.1039/d5sm00539f
SN - 1744-6848
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Suppressed Transition and Dynamic self-asembly of ionic superdiscs in cylindrical nanochannels
N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing phase transition behaviors and relaxation dynamics. Here, we investigate the molecular mobility and electrical conductivity of a columnar ionic liquid crystal confined in self-ordered nanoporous alumina oxide membranes of pore size ranging from 180 nm down to 25 nm. We use nano-broadband dielectric spectroscopy (BDS) and calorimetry to study the dynamics and phase behavior. Calorimetric investigation reveals a complete suppression of the columnar – isotropic transition, while the plastic crystalline – columnar transition temperature decreases with inverse pore size and deviates from the Gibbs – Thomson equation.
For the bulk case, BDS detects two relaxation modes in the crystalline phase, the γ relaxation and the α1 relaxation, and two relaxation modes in the columnar phase, the α2 and α3 relaxation. All relaxation modes slow down for the confined case compared to the bulk. However, a new relaxation mode reflecting the interfacial layer emerges for the 80 and 25 nm. We discuss the possible molecular origins of the different relaxation modes observed. For the bulk ILC, a clear jump of 4 orders of magnitude in the absolute values of DC conductivity occurs at the transition from the plastic crystalline to hexagonal columnar phase, for the confined ILC, this transition is smooth. DC conductivity is reduced for the confined case, except for the 25nm, where the values are similar to the bulk.
T2 - DPG Spring Meet 2023
CY - Dresden, Germany
DA - 26.03.2023
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2023
AN - OPUS4-57345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maaß, Robert
T1 - Opening Ideas
N2 - This article explores the strategic and operational framework of programming within The Minerals, Metals & Materials Society (TMS). Operating as a grassroots organization, the Society faces the unique challenge of balancing member autonomy with the necessity of a cohesive, high-quality technical program. The author, serving as the TMS Program Director, reflects on the leadership's role as an enabler, emphasizing that success is defined by the ability to support the symposium-organizer community while maintaining the internationally respected TMS brand.
KW - Association Management
KW - Symposium Programming
KW - Grassroots Governance
PY - 2026
DO - https://doi.org/10.1007/s11837-026-08312-7
SN - 1047-4838
SP - 1
PB - Springer Science and Business Media LLC
AN - OPUS4-65837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
T1 - Growth Kinetics and Molecular Mobility of the Adsorbed Layer of Poly(bisphenol-A Carbonate) (PBAC), Polysulfone (PSU), and Poly (2-Vinyl Pyridine) (P2VP)
N2 - Interactions between a polymer and a substrate interface play a vital role in understanding the improvement in thin film material properties as well as serving as a model for nanocomposites. For any non-repulsive polymer-substrate interactions, polymer segments form an irreversibly adsorbed layer and show a slowdown in the glassy dynamics and thus an increase in the thermal glass transition temperature compared to the bulk-like values. The growth kinetics of the adsorbed layer showed a deviation for both poly (bisphenol-A carbonate) (PBAC) and polysulfone (PSU), two bulky polymers containing a functional group (phenyl ring) in the backbone, compared to conventional polymers previously studied like poly-2-vinyl pyridine (P2VP). This deviation was attributed to the bulkiness of the phenyl rings. . Further investigations into the influence of the adsorbed layer on glassy dynamics were conducted. The molecular mobility and glass transition for thin films of PBAC and PSU were compared to bulk samples of each polymer. Broadband dielectric spectroscopy, atomic force microscopy, and ellipsometry were primarily used and additionally supported by sum frequency generation spectroscopy.
T2 - Deutsche Physikalische Gesellschaft (DPG) Tagung
CY - Berlin, Germany
DA - 17.03.2024
KW - Thin films
KW - Adsorbed Layer
KW - Atomic Force Microscopy
KW - Ellipsometry
KW - Dielectric Spectroscopy
PY - 2024
AN - OPUS4-59821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Nanoscale Confinement Effects in Thin Films of Rigid-Backbone Polymers
N2 - Thin polymer films play a crucial role in modern technologies, with applications spanning flexible electronics, membranes, coatings, and nanodevices. Their reduced dimensions result in unique physical behavior, often deviating significantly from bulk properties due to confinement and interfacial effects. In this study, we investigate how nanoscale confinement and polymer–substrate interactions influence the structural and dynamic properties of supported thin films of two rigid-backbone polymers: poly(bisphenol A carbonate) (PBAC) and polysulfone (PSU). Emphasis was placed on the development of adsorbed interfacial layers, molecular mobility, and the glass transition behavior as functions of film thickness and thermal history. Using a multimodal experimental approach—including Atomic Force Microscopy (AFM), Broadband Dielectric Spectroscopy (BDS), Differential and Fast Scanning Calorimetry (DSC, FSC), and Ellipsometry—we characterized adsorption kinetics, desorption processes, and segmental dynamics across a wide range of thicknesses and annealing conditions. Special attention was given to the formation and growth regimes of the adsorbed polymer layers, including a newly observed pre-growth stage, and their effect on thermal and dielectric relaxation behavior. To probe dynamics in ultrathin films, two dielectric electrode configurations—crossed electrode capacitors and nanostructured electrodes—were employed, enabling measurements down to 10 nm and isolated adsorbed layer. This comprehensive analysis provides insight into how one-dimensional confinement and interfacial interactions modulate macromolecular behavior, which is critical for the design of functional nanostructured polymeric systems in advanced applications.
T2 - 10th International Discussion Meeting on Relaxations in Complex Systems (10thIDMRCS)
CY - Barcelona, Spanien
DA - 20.06.2025
KW - Thin films
PY - 2025
AN - OPUS4-63858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Ghasem Zadeh Khorasani, Media
A1 - Cano Murillo, Natalia
A1 - Elert, Anna Maria
A1 - Sturm, Heinz
ED - Glatzel, T.
T1 - Bulk chemical composition contrast from attractive forces in AFM force spectroscopy
N2 - A key application of atomic force microscopy (AFM) is the measurement of physical properties at sub-micrometer resolution. Methods such as force–distance curves (FDCs) or dynamic variants (such as intermodulation AFM (ImAFM)) are able to measure mechanical properties (such as the local stiffness, kr) of nanoscopic heterogeneous materials. For a complete structure–property correlation, these mechanical measurements are considered to lack the ability to identify the chemical structure of the materials. In this study, the measured attractive force, Fattr, acting between the AFM tip and the sample is shown to be an independent measurement for the local chemical composition and hence a complete structure–property correlation can be obtained. A proof of concept is provided by two model samples comprised of (1) epoxy/polycarbonate and (2) epoxy/boehmite. The preparation of the model samples allowed for the assignment of material phases based on AFM topography. Additional chemical characterization on the nanoscale is performed by an AFM/infrared-spectroscopy hybrid method. Mechanical properties (kr) and attractive forces (Fattr) are calculated and a structure–property correlation is obtained by a manual principle component analysis (mPCA) from a kr/Fattr diagram. A third sample comprised of (3) epoxy/polycarbonate/boehmite is measured by ImAFM. The measurement of a 2 × 2 µm cross section yields 128 × 128 force curves which are successfully evaluated by a kr/Fattr diagram and the nanoscopic heterogeneity of the sample is determined.
KW - AFM force spectroscopy
KW - Composites
KW - Principle component analysis
KW - Structure–property correlation
KW - Van der Waals forces
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520175
DO - https://doi.org/10.3762/bjnano.12.5
SN - 2190-4286
VL - 12
IS - 5
SP - 58
EP - 71
PB - Beilstein Institute
CY - Frankfurt am Main
AN - OPUS4-52017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezera, Marek
A1 - Alamri, S.
A1 - Hendriks, W. A. P. M.
A1 - Hertwig, Andreas
A1 - Elert, Anna Maria
A1 - Bonse, Jörn
A1 - Kunze, T.
A1 - Lasagni, A. F.
A1 - Römer, G. R. B. E.
T1 - Hierarchical micro-/nano-structures on polycarbonate via UV pulsed laser processing
N2 - Hierarchical micro/-nanostructures were produced on polycarbonate polymer surfaces by employing a two-step UV-laser processing strategy based on the combination of Direct Laser Interference Patterning (DLIP) of gratings and pillars on the microscale (3 ns, 266 nm, 2 kHz) and subsequently superimposing Laser-induced Periodic Surface Structures (LIPSS; 7–10 ps, 350 nm, 100 kHz) which adds nanoscale surface features. Particular emphasis was laid on the influence of the direction of the laser beam polarization on the morphology of resulting hierarchical surfaces. Scanning electron and atomic force microscopy methods were used for the characterization of the hybrid surface structures. Finite-difference time-domain (FDTD) calculations of the laser intensity distribution on the DLIP structures allowed to address the specific polarization dependence of the LIPSS formation observed in the second processing step. Complementary chemical analyzes by micro-Raman spectroscopy and attenuated total reflection Fourier-transform infrared spectroscopy provided in-depth information on the chemical and structural material modifications and material degradation imposed by the laser processing. It was found that when the linear laser polarization was set perpendicular to the DLIP ridges, LIPSS could be formed on top of various DLIP structures. FDTD calculations showed enhanced optical intensity at the topographic maxima, which can explain the dependency of the morphology of LIPSS on the polarization with respect to the orientation of the DLIP structures. It was also found that the degradation of the polymer was enhanced for increasing accumulated fluence levels.
KW - Direct laser interference patterning
KW - Laser-induced periodic surface structures (LIPSS)
KW - Polycarbonate
KW - Hierarchical structures
KW - Surface functionalization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509101
DO - https://doi.org/10.3390/nano10061184
SN - 2079-4991
VL - 10(6)
IS - Special issue "Laser-generated periodic nanostructures"
SP - 1184-1
EP - 1184-19
PB - MDPI
CY - Basel
AN - OPUS4-50910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Silbernagl, Dorothee
A1 - Rautenberg, Max
A1 - Schmid, Thomas
A1 - Feiler, Torvid
A1 - Reimann, K.
A1 - Ghalgaoui, A.
A1 - Sturm, Heinz
A1 - Paulus, B.
A1 - Emmerling, Franziska
T1 - A Mechanistic Perspective on Plastically Flexible Coordination Polymers
N2 - Mechanical flexibility in single crystals of covalently bound materials is a fascinating and poorly understood phenomenon. We present here the first example of a plastically flexible one-dimensional (1D) coordination polymer. The compound [Zn(m-Cl)2(3,5-dichloropyridine)2]n is flexible over two crystallographic faces. Remarkably, the single crystal remains intact when bent to 1808. A combination of microscopy, diffraction, and spectroscopic studies have been used to probe the structural response of the crystal lattice to mechanical bending. Deformation of the covalent polymer chains does not appear to be responsible for the observed macroscopic bending. Instead, our results suggest that mechanical bending occurs by displacement of the coordination polymer chains. Based on experimental and theoretical evidence, we propose a new model for mechanical flexibility in 1D coordination polymers. Moreover, our calculations propose a cause of the different mechanical properties of this compound and a structurally similar elastic material
KW - Coordination polymer
KW - Flexible crystals
KW - Mechanical properties
KW - Plastic deformation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504755
DO - https://doi.org/10.1002/anie.201914798
VL - 59
IS - 14
SP - 5557
EP - 5561
PB - Wiley-VCH
AN - OPUS4-50475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hernández García, María Amparo
T1 - SAF-based optical biosensor with 3D-printed free-form optics for targeted explosives immuno-detection
N2 - Guaranteeing safety and security of citizens requires a significant effort and innovative tools from national and international agencies and governments, especially when it comes to the field of explosives detection. The need to detect Improvised Explosive Devices (IEDs) and Home-made Explosives (HMEs) at a point of suspicion, has grown rapidly due to the ease with which the precursors can be obtained and the reagents synthesised. The limited availability of immunoanalytical tools for HME detection presents an opportunity for the development of new devices, which enable a rapid detection and recognise the target analyte with high specificity and sensitivity. In this work, we introduce an optical biosensor for highly specific and sensitive HME detection. The immunoassay system is placed in a hydrogel environment permeable to the analyte and transparent to light interrogating the fluorescently labelled antibodies. The readout of the immunoanalytical system is realized with Supercritical Angle Fluorescence (SAF), an advanced microscopy technique. To accomplish this, we made use of recent, commercial high resolution (< 22 µm) Liquid Crystal Display 3D printers to fabricate a parabolic optical element with high refractive index (RI>1.5) and transmission values (>90%) from photo-resin. Aiming at a new generation of sensors, which not only can meet the requirements of trace detection, but can also be used for substance identification, the combination of immunoanalytical recognition with SAF detection offers a modularity and versatility that is principally well suitable for the measurements of target analytes at trace levels.
T2 - 8th International conference in Biosensing Technology
CY - Seville, Spain
DA - 12.05.2024
KW - 3D printing
KW - Biosensor
KW - Fluorescence
KW - Explosives
PY - 2024
AN - OPUS4-60561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frunza, L.
A1 - Zgura, I
A1 - Ganea, C. P.
A1 - Schönhals, Andreas
T1 - Molecular dynamics of alkyl benzoate liquid crystals in the bulk state and in the surface layer of their composites with oxide nanopowders
N2 - This paper presents the results concerning monotropic nematic liquid crystals 4-pentylphenyl 40-alkyl benzoate (5PnB) (n = 3 or 5 carbon atoms in the alkyl chain). Their mesophase properties were supported by images of the polarized optical microscopy. Molecular dynamics in the bulk samples or in the composites prepared with aerosil A380 was investigated by broadband dielectric spectroscopy in a large temperature range, appropriately chosen. Thermo gravimetric and infrared investigations were additionally performed. The data were compared with those of structurally related nematics like cyanophenyl pentyl benzoates, which have a cyan group instead of the pentyl chain. The dielectric spectra of the bulk 3P5B and 5P5B demonstrate a dielectric behavior with several relaxation processes as expected for nematic liquid crystals. The temperature dependence of the relaxation rates (and of the dielectric strength) seems to have two distinguished regimes. Thus, in the isotropic state, at higher temperatures the data obey the Vogel–Fulcher–Tammann law, whereas an Arrhenius law is fitted at lower temperature, in a close similarity to the behavior of a constrained dynamic glass transition. Samples with a high density of silica (larger than 7 g aerosil/1 g of 5PnB) were prepared to observe a thin layer adsorbed on the particle surface; it was estimated that almost each guest 5PnB molecule interacts with the aerosil surface. For the composites only one main relaxation process is observed at frequencies much lower than those for the corresponding bulk, which was assigned to the dynamics of the molecules in the surface layer. Infrared spectroscopy shows that these molecules interact with the surface by the ester carbonyl group leading to the monolayer self-assembly at liquid–solid interface. We note once more the importance of the functional unit(s) for the interaction with the hydroxyl groups on the aerosil surface.
KW - Liquid crystals
PY - 2022
DO - https://doi.org/10.1016/j.molliq.2022.119374
SN - 0167-7322
VL - 359
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-54867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raab, A. R.
A1 - Grießler, T. R.
A1 - Rück, D.
A1 - Li, Z.
A1 - Zens, A.
A1 - Bruckner, J. R.
A1 - Huber, P.
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
A1 - Laschat, S.
T1 - Salt complexation drives liquid crystalline selfassembly in crown ether–amino acid hybrids
N2 - Crown ether–amino acid hybrids represent a promising class of amphiphilic molecules combining ion recognition with self-assembly capabilities. Despite extensive studies on their binding properties, the influence of inorganic salt complexation on their liquid crystalline behaviour remains underexplored. Here we synthesized amphiphilic [18]-crown-6 derivatives of L-dihydroxyphenylalanine and tetrahydroisoquinoline analogues, systematically investigating the effects of alkyl chain length and salt type on mesophase formation. Complexation with various salts induced liquid crystalline phases, transitioning from smectic A to columnar hexagonal structures as anion size and alkyl chain length increased.
Structural analyses and electron density mapping revealed assembly into charged superdiscs forming columnar stacks with tunable ion channels. Broadband dielectric spectroscopy highlighted differences in molecular mobility and conductivity linked to molecular design. These findings establish salt complexation as a key strategy to control self-assembly and ion transport in crown ether–amino acid hybrids, advancing their potential in responsive soft materials and ion-conductive applications.
KW - Ionic liquid crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655986
DO - https://doi.org/10.1039/d5tc04129e
SP - 1
EP - 18
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed A.
A1 - Raab, A. R.
A1 - Szymoniak, Paulina
A1 - Li, Z.
A1 - Huber, P.
A1 - Laschat, S.
A1 - Schönhals, Andreas
T1 - Molecular mobility and electrical conductivity of amino acid-based (DOPA) ionic liquid crystals in the bulk state and nanoconfinement
N2 - This study explores the molecular mobility, phase behavior, and electrical conductivity of dihydroxyphenylalanine-based ionic liquid crystals (DOPAn, with alkyl side chains n = 12, 14, 16) featuring cyclic guanidiniumchloride headgroups, in both bulk and nanoconfined states. Using broadband dielectric spectroscopy, differential scanning calorimetry, and fast scanning calorimetry, the research uncovers a complex interplay between molecular structure, self-assembly, and molecular mobility. In bulk, DOPAn shows a phase sequence from plastic crystalline to hexagonal columnar and isotropic phases, driven by superdisc formation and columnar organization. Multiple relaxation processes are identified: localized side-chain dynamics (γ-relaxation), ionic headgroup or core motions (α1-relaxation), and cooperative alkyl domain fluctuations (α2-relaxation). Conductivity decreases with increasing side chain length. Under nanoconfinement in anodic aluminum oxide membranes, phase behavior changes: the Colh–Iso transition is suppressed, and a new α3-relaxation appears, linked to dynamics in an adsorbed interfacial layer. DC conductivity drops by up to four orders of magnitude due to confinement effects, altered molecular orientation, and phase transitions—especially the emergence of a nematic-like state in DOPA16. These findings highlight the importance of molecular design, pore geometry, and surface chemistry in tuning ionic liquid crystal properties for advanced applications in nanofluidics, ion transport, and responsive materials.
KW - Ionic Liquid Crystals
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639657
DO - https://doi.org/10.1039/d5cp02406d
SN - 1463-9084
SP - 1
EP - 17
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Fürstenwerth, Paul
A1 - Würth, Christian
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
T1 - Validated workflows for preparing and characterizing core-stained and surface-labeled fluorescent polymer particles with simple commercial automation tools
N2 - Preparation workflows of fluorescent nm- and µm-sized polymer particles used as reporters in fluorescent assays, bioimaging, and sensing studies or calibration tools for fluorescence methods in the life sciences can be time-consuming and labor-intensive. Also, the outcome can be operator dependent. Here, we present simple and cost-efficient automated workflows for dye loading and surface labeling of polystyrene particles (PSP), using a commercial self-programmable pipetting robot. For developing and fine-tuning automated staining workflows, hydrophobic Nile Red (NR) was incorporated into 100 nm, 200 nm, and 1000 nm PSP by an adapted swelling procedure of premanufactured particles in the presence of hydrophobic dyes, thereby confirming its reliability and versatility. Subsequent expansion of our automation concept to the labeling of carboxylated PSP with pH-sensitive 6-aminofluorescein (6-AMF) and aminated PSP with pH-responsive fluorescein isocyanate (FITC) demonstrated its broad applicability. All automated workflows were optimized and validated by gravimetry and spectroscopic measurements with a microtiter plate (MTP) reader in absorption and fluorescence mode to ensure particle recovery and reproducible fluorescence features and determine PSP dye loading and labeling efficiencies. Comparison with the manual fabrication of NR-stained PSP using an established swelling protocol showed that our automation approach utilizing a pipetting robot considerably reduced the variability in particle recovery and dye loading efficiency. Overall, our simple, labor- and time-efficient workflows with inexpensive and broadly available commercial automation tools present attractive alternatives to manual particle loading and labeling and provide the basis for fast parameter screening, parallel processing, and decreased hands-on time.
KW - Automation
KW - Fluorescent polymer beads
KW - Dye staining
KW - Fluorescent labeling
KW - Nanomaterials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658451
DO - https://doi.org/10.1007/s00216-026-06443-z
SN - 1618-2642
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Multiple glassy dynamics of a homologous series of triphenylene-based columnar liquid crystals – A study by broadband dielectric spectroscopy, advanced calorimetry and Neutron Scattering
N2 - Hexakis(n-alkyloxy)triphenylene) (HATn) consisting of an aromatic triphenylene core and alkyl side chains are model discotic liquid crystal (DLC) systems forming a columnar mesophase. In the mesophase, the molecules of HATn self-assemble in columns, which has one-dimensional high charge carrier mobility along the columns. Here, a homologous series of HATn with different length of the alkyl chain (n=5,6,8,10,12) is investigated using differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and advanced calorimetric techniques including fast scanning calorimetry (FSC) and specific heat spectroscopy (SHS). The investigation of the phase behavior was done utilizing DSC experiments and the influence of the alkyl chain length on the phase behavior was revealed. By the dielectric investigations probing the molecular mobility, a γ-relaxation due to localized fluctuations as well as two glassy dynamics the αcore and αalkyl relaxation were observed in the temperature range of the plastic crystalline phase. Moreover, the observed glassy dynamics were further studied employing advanced calorimetry. All observed relaxation processes are attributed to the possible specific molecular fluctuations and discussed in detail. From the results a transition at around n=8 from a rigid constrained (n=5,6) to a softer system (n=10,12) on a molecular lenght scale was revealed with increasing alkyl chain length. A counterbalance of two competing effects of a polyethylene like behavior of the alkyl chains in the intercolumnar domains and self-organized confinement is discussed in the context of a hindered glass transition.
T2 - 11th Conferenz on Broadband Dielectric Spectroscopy and its Applications
CY - San Sebastian, Spain
DA - 04.09.2022
KW - Discotic Liquid Crystals
PY - 2022
AN - OPUS4-55672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Omar, Hassan
T1 - Growth Kinetics and Molecular Mobility of the Adsorbed Layer of Poly(bisphenol-A Carbonate) (PBAC), Polysulfone (PSU), and Poly (2-Vinyl Pyridine) (P2VP)
N2 - Interactions between a polymer and a substrate interface play a vital role in understanding the improvement in thin film material properties as well as serving as a model for nanocomposites. For any non-repulsive polymer-substrate interactions, polymer segments form an irreversibly adsorbed layer and show a slowdown in the glassy dynamics and thus an increase in the thermal glass transition temperature compared to the bulk-like values. The growth kinetics of the adsorbed layer obey a two-step mechanism: formation of immobilized layer with flat segmental conformations and a loosely bound layer with stretched chains pinned to the surface. Here the adsorbed layer was studied for: poly (bisphenol-A carbonate) (PBAC) and polysulfone (PSU), two bulky polymers containing a functional group (phenyl ring) in the backbone and compared to poly (2-vinyl pyridine) (P2VP), where the backbone is a vinyl-derivative and the functional group (pyridine) is in the side chain. The growth kinetics for PBAC and PSU were found to deviate from the well-known mechanism, observed for polymers such as P2VP. Atomic force microscopy and ellipsometry were used for this investigation and was additionally supported by broadband dielectric spectroscopy.
T2 - 11th International Conference on Times of Polymers (TOP) and Composites
CY - Ischia, Italy
DA - 11.06.2023
KW - Adsorbed Layer
KW - Dielectric Spectroscopy
KW - Atomic Force Microscopy
KW - Ellipsometry
KW - Growth Kinetics
KW - Molecular Mobility
PY - 2023
AN - OPUS4-57709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Böhning, Martin
A1 - Zamponi, M.
A1 - Frick, B.
A1 - Appel, M.
A1 - Günther, G.
A1 - Russina, M.
A1 - Alentiev, D.
A1 - Bermeshev, M.
A1 - Zorn, R.
T1 - Microscopic dynamics of highly permeable super glassy polynorbornenes revealed by quasielastic neutron scattering
N2 - The molecular dynamics of addition-type poly(tricyclononenes) with Si-substituted bulky side groups has been investigated by a combination of neutron time-of-flight and neutron backscattering spectroscopy methods on a time scale from 0.1 ps to ca. 3 ns. The investigated poly(tricyclononenes) PTCNSi1 and PTCNSi2g both bear a high microporosity which makes them promising candidates for active separation layers for gas separation membranes. At least for larger gas molecules it is assumed that the pathways for diffusion require an enlargement of pre-existing micropores in terms of an activated zone. A low temperature relaxation process was found for both polymers by the performed neutron scattering experiments. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized. For PTCNSi1 (3 methyl groups in the monomeric unit) it was found that all methyl groups take part in the methyl group rotation whereas for PTCNSi2g (6 methyl groups in monomeric unit) a considerable number of methyl groups are blocked in their rotation. This immobilization of methyl groups is due to the sterically demanding arrangement of the methyl groups in PTCNSi2g. This conclusion is further supported by the result that the activation energy for the methyl group rotation is three times higher for PTCNSi2g than that of PTCNSi1.
KW - Highly permeably polynorbornenes
KW - Polymers of intrinsic microporosity
KW - Gas separation membranes
KW - Quasielastic neutron scattering
PY - 2021
DO - https://doi.org/10.1016/j.memsci.2021.119972
SN - 0376-7388
VL - 642
PB - Elesevier B.V.
AN - OPUS4-53508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
A1 - Böhning, Martin
A1 - Zorn, Reiner
A1 - Schönhals, Andreas
T1 - Inelastic and quasielastic neutron scattering experiments on microporous membranes fro green separation processes
N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. These polymers are characterized by a high permeability and reasonable permselectivity. The latter point is somehow surprising because for microporous systems a more Knudson-like diffusion is expected then a size dependent temperature activated sieving process. It was argued in the framework of a random gate model that molecular fluctuations on a time scale from ps to ns are responsible for the permselectivity.
Here series of polymers of intrinsic microporosity (PIMs) as well as microporous polynorbornenes with bulky Si side groups and a rigid backbone are considered. The polymers have different microporosity characterized by high BET surface area values.
First inelastic time-of-flight neutron scattering measurements were carried out to investigate the low frequency density of state (VDOS). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. It was found that the frequency of the maximum position of the Boson peak correlates with the BET surface area value.
Secondly elastic scans as well as quasielastic neutron scattering measurements by a combination of neutron time-of-flight and backscattering have been out. A low temperature relaxation process was found for both polymers. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized.
The neutron scattering experiments were accompanied by fast scanning calorimetry and broadband dielectric investigations as well as atomistic molecular dynamic simulations.
T2 - Kolloquiumsvortrag an der Technischen Universität München
CY - Garching, Germany
DA - 20.11.2023
KW - Polymers with intrinsic microporosity
PY - 2023
AN - OPUS4-59036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmid, Thomas
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative Analysis by Raman and other Micro & Nanospectroscopic Imaging Techniques
N2 - In the present talk the basics of the Raman spectroscopy and particularly of Raman microscopy are explained. Advantages and disadvantages of the method are highlighted through selected case studies. In the second part of the lecture examples of correlative imaging with electron, X-ray, ion and optical microscopies from micro- to the nanoscale are highlighted.
T2 - Charisma School on Raman Harmonisation
CY - Turin, Italy
DA - 19.10.2022
KW - Raman
KW - Correlative Imaging
KW - Microscopy
KW - Hyperspectral imaging
PY - 2022
UR - https://amdgroup.inrim.it/events/vamas-sc-meeting-47/program-sc47
AN - OPUS4-56094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Suppressed Transition and Dynamic self-asembly of ionic superdiscs in cylindrical nanochannels
N2 - Liquid crystalline mesophases in nanoconfinement exhibit intriguing phase transition behaviors and relaxation dynamics. Here, we investigate the molecular mobility and electrical conductivity of a columnar ionic liquid crystal confined in self-ordered nanoporous alumina oxide membranes of pore size ranging from 180 nm down to 25 nm. We use nano-broadband dielectric spectroscopy (BDS) and calorimetry to study the dynamics and phase behavior. Calorimetric investigation reveals a complete suppression of the columnar – isotropic transition, while the plastic crystalline – columnar transition temperature decreases with inverse pore size and deviates from the Gibbs – Thomson equation.
For the bulk case, BDS detects two relaxation modes in the crystalline phase, the γ relaxation and the α1 relaxation, and two relaxation modes in the columnar phase, the α2 and α3 relaxation. All relaxation modes slow down for the confined case compared to the bulk. However, a new relaxation mode reflecting the interfacial layer emerges for the 80 and 25 nm. We discuss the possible molecular origins of the different relaxation modes observed. For the bulk ILC, a clear jump of 4 orders of magnitude in the absolute values of DC conductivity occurs at the transition from the plastic crystalline to hexagonal columnar phase, for the confined ILC, this transition is smooth. DC conductivity is reduced for the confined case, except for the 25nm, where the values are similar to the bulk.
T2 - APS March Meeting 2023
CY - Las Vegas, NV, USA
DA - 05.03.2023
KW - Ionic Liquid crystals
KW - Nanoconfinement
KW - Conductivity
PY - 2023
AN - OPUS4-57342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hernández García, María Amparo
A1 - Rurack, Knut
A1 - Bell, Jérémy
T1 - Rapid fabrication of optical elements for sensing applications using a standard SLA printer
N2 - The demand for compact, high-performance optical components has driven the development of increasingly sophisticated and miniaturized optical elements, often requiring complex and costly fabrication methods. In this work, we propose a cost-effective and accessible methodology for the fabrication of lenses and free-form optics using a commercially available stereolithography (SLA) 3D printer. A systematic characterization of six transparent photopolymer resins was conducted in terms of their spectroscopic, optical, and morphological properties, i.e., surface and dimensional properties. The evaluation encompassed parameters such as transmittance, autofluorescence, refractive index, and surface roughness. A straightforward and robust printing and posttreatment protocol was developed, facilitating the fabrication of optical components with over 80% transmittance, minimal intrinsic fluorescence, and a surface quality that is compatible with demanding optical applications. The fabricated components demonstrated excellent dimensional fidelity to digital designs and high reproducibility. To demonstrate the versatility of this approach, aspherical, miniaturized, and free-form lenses were designed and integrated into three fluorescence sensing systems, including oil (strip based) and chlorine (microfluidic based) detection platforms, as well as a smartphone-based SARSCoV-2 biosensor. The integration of customized 3Dprinted optics has been shown to improve signal collection and readout performance, thereby highlighting the potential of this approach for broad application by a wide range of user groups in rapid prototyping and use in miniaturized optical systems. This work represents a significant advancement in the field of additive manufacturing, particularly in relation to the development of functional photonic devices. Furthermore, it opens new prospects for sensor applications in biosensing, microfluidics, imaging, and integrated optics.
KW - 3D-printing
KW - Free-form
KW - Prototyping
KW - Optical resin
KW - Surface-finishing
KW - Fluorescence
KW - Sensor
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655558
DO - https://doi.org/10.37188/lam.2026.024
SN - 2689-9620
VL - 7
SP - 1
EP - 12
PB - Light Publishing Group
CY - Foshan City
AN - OPUS4-65555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Falkenhagen, Jana
A1 - Panne, Ulrich
A1 - Hiller, W.
A1 - Gruendling, T.
A1 - Staal, B.
A1 - Lang, C.
A1 - Lamprou, A.
T1 - Simultaneous characterization of poly(acrylic acid) andpolysaccharide polymers and copolymers
N2 - Copolymer products that result from grafting acrylic acid and other hydrophilicmonomers onto polysaccharides have recently gained significant interest in researchand industry. Originating from renewable sources, these biodegradable, low toxicity,and polar copolymer products exhibit potential to replace polymers from fossil sourcesin several applications and industries. The methods usually employed to character-ize these copolymers are, however, quite limited, especially for the measurement ofbulk properties. With more sophisticated applications, for example, in pharmaceu-tics requiring a more detailed analysis of the chemical structure, we describe a newapproach for this kind of complex polymers. Our approach utilizes chromatographyin combination with several detection methods to separate and characterize reactionproducts of the copolymerization of acrylic acid and chemically hydrolyzed starch.These samples consisted of a mixture of homopolymer poly (acrylic acid), homopoly-mer hydrolyzed starch, and – in a lower amount – the formed copolymers. Several chro-matographic methods exist that are capable of characterizing either poly (acrylic acid)or hydrolyzed starch. In contrast, our approach offers simultaneous characterization ofboth polymers. The combination of LC and UV/RI offered insight into the compositionand copolymer content of the samples. Size exclusion chromatography experimentsrevealed the molar mass distribution of homopolymers and copolymers. FTIR inves-tigations confirmed the formation of copolymers while ESI-MS gave more details onthe end groups of hydrolyzed starches and poly (acrylic acids). Evidence of copolymerstructures was obtained through NMR measurements. Finally, two-dimensional chro-matography led to the separation of the copolymers from both homopolymers as wellas the additional separation of sodium clusters. The methods described in this work area powerful toolset to characterize copolymerization products of hydrolyzed starch andpoly(acrylic acid). Together, our approach successfully correlates the physicochemicalproperties of such complex mixtures with their actual composition.
KW - 2D chromatography
KW - LC-MS
KW - SEC
KW - Renewable copolymers
KW - Grafting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508873
DO - https://doi.org/10.1002/ansa.202000044
SP - 1
EP - 12
PB - Wiley-VCH Verlag-GmbH&Co. KGaA
CY - Weinheim
AN - OPUS4-50887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Denkler, Tilman
T1 - The Metabuilding Labs approach to Quality Assurance – Standard Operating Procedures and Work Instructions for the O3BETs
N2 - The development of the Standard Operating Procedures and Work Instructions for the O3BETs by setting up 3 working roups during Summer 2024 aredescribed. Major achievements are shown and future work is outlined.
T2 - 6th General Meeting Metabuilding Labs
CY - Szentender, Hungary
DA - 26.11.2024
KW - Open innovation test bed
KW - Metabuilding Labs
KW - Quality management
PY - 2024
AN - OPUS4-61866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Czeskleba, Denis
A1 - Rhode, Michael
A1 - Kannengiesser, Thomas
ED - Lippold, John C.
ED - Fink, Carolin
ED - Valiente Bermejo, Maria Asuncion
ED - Westin, Elin Marianne
T1 - Numerical Simulation of Hydrogen Diffusion in Thick-Walled S690 SAW Joints: Comparison of Microstructure-Dependent Diffusion and Welding Heat Input Effects
N2 - S690 steel is increasingly employed in modern steel construction, including building, plant, and mobile crane applications, due to their high strength and weldability. Submerged arc welding (SAW) is commonly used for these thick-walled structures but poses a risk of delayed hydrogen-assisted cold cracking (HACC). The influence of microstructure-dependent diffusion coefficients (DH) on hydrogen accumulation and distribution during welding and cooling remains poorly understood. In this study, the HACC susceptibility of SAW joints of thermomechanically rolled (MC) and quenched and tempered (Q) variants of S690 steel were compared, followed by electrochemical hydrogen permeation tests to determine the microstructure-specific DH. A numerical model was developed to analyze hydrogen diffusion as a function of temperature, time, and microstructure. Results showed that the MC-grade exhibited slightly faster hydrogen diffusion than the Q-grade. However, simulations indicated that higher welding heat input and increased plate thickness had a significantly greater impact on hydrogen retention than microstructure-dependent diffusion effects. These findings suggest that while differences in hydrogen diffusivity exist between S690MC and S690Q, microstructure-specific diffusion plays a minor role in HACC risk. Instead, proper control of welding parameters is crucial for mitigating HACC, particularly in thick-plate, multi-layer SAW joints.
T2 - 5th International Conference on Cracking Phenomena in Welding and Additive Manufacturing
CY - Trollhättan, Sweden
DA - 13.03.2025
KW - Hydrogen assisted cracking
KW - Numerical simulation
KW - Submerged arc welding
KW - Microstructure
KW - Hydrogen diffusion
PY - 2026
SN - 978-3-032-16393-6
DO - https://doi.org/10.1007/978-3-032-16393-6_18
SP - 364
EP - 393
PB - Springer Nature Switzerland AG
CY - Cham (Switzerland)
AN - OPUS4-65829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Schroepfer, Dirk
A1 - Rhode, Michael
A1 - Kannengiesser, Thomas
ED - Lippold, J.C.
ED - Valiente Bermejo, M. A.
ED - Fink, C.
ED - Westin, E. M.
T1 - Influence of Residual Stresses and Heat Control on Stress Relief Cracking in a CrMoV Steel Mockup
N2 - Preventing failures in the manufacture or operation of petrochemical reactors made from creep-resistant, low-alloy steels such as 13CrMoV9-10 still requires research, despite over 60 years of investigation into the field of stress relief cracking. Welding this steel grade requires care. This is due to its low toughness and high strength in the as-welded condition if not heat treated after welding, combined with an increased susceptibility to cracking during stress relaxation.
Previous research on cracking has focused on metallurgical factors; little knowledge has been gained on cracking under real-life restraint conditions. In this work,the influence of welding heat control on cracking was investigated by simulating the manufacturing conditions prevailing in the construction of petrochemical reactors using a weld mockup. Cracks formed during post-weld heat treatment in a temperature range between 300 °C and 500 °C. Compared to small scale samples, the toughness of the restrained welds was significantly lower. SEM and TEM analyses of the samples revealed early ageing due to precipitation of carbides during post-weld heat treatment under restraint. An overview of how a comprehensive assessment of the integrity of submerged arc welded CrMoV steels can be achieved is provided.
T2 - 5th International Conference on Cracking Phenomena in Welding and Additive Manufacturing
CY - Trollhättan, Sweden
DA - 12.03.2025
KW - Stress relief cracking
KW - Residual stress
KW - Sub-merged arc welding
KW - Mockup
PY - 2026
SN - 978-3-032-16393-6
SN - 978-3-032-16392-9
DO - https://doi.org/10.1007/978-3-032-16393-6_17
SP - 336
EP - 363
PB - Springer
CY - Cham
AN - OPUS4-65823
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - Mikrobielle Einflüsse auf Wasserstoffspeicherung: Materialien, Abbauprozesse und Teststrategien
N2 - Wasserstoff gilt als Schlüsseltechnologie für die Energiewende – doch seine sichere Anwendung stellt neue Anforderungen an Technik, Infrastruktur und Personal. Die Veranstaltung „H₂ Sicherheit“ bietet eine umfassende Plattform, um sich über die sicherheitsrelevanten Aspekte von Wasserstoff zu informieren und praxisnahe Lösungen kennenzulernen. Expert:innen aus Forschung, Industrie und Netzbetrieb geben Einblicke in aktuelle Entwicklungen, Herausforderungen und Best Practices. Fokus dieser Präsentation war der Mikrobielle Einfluss bei der unterirdischen Speicherung von Wasserstoff und das neuartige Testsystem (MISTRAL)
T2 - DVGW- H₂ Sicherheit
CY - Online meeting
DA - 24.03.2026
KW - Wasserstoff
KW - Unterirdische geologische Formationen
KW - MISTRAL
KW - MIC
KW - Hochdruckbehälter
KW - Biokorrosion
PY - 2026
UR - https://www.dvgw-kongress.de/veranstaltungen/gas/h2-sicherheit#collapse-8103
AN - OPUS4-65810
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hodoroaba, Vasile-Dan
T1 - Capacity building and Knowledge Exchange in Research Management from the Perspective of a Project Coordinator
N2 - In the Seminar "Capacity building and Knowledge Exchange in Research Management" following three points are presented in detail:
- Example of a successfully completed international project,
- Role of institutional support in project success, and
- Practical challenges and lessons learned from a coordinator‘s perspective.
T2 - Seminar "Capacity building and Knowledge Exchange in Research Management"
CY - Online meeting
DA - 25.03.2026
KW - Research management
KW - Institutional support
KW - Project coordination
KW - European projects
PY - 2026
AN - OPUS4-65811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Zengchao
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
A1 - Panne, Ulrich
A1 - Weidner, Steffen
T1 - Separation of polystyrene nanoparticles bearing different carboxyl group densities and functional groups quantification with capillary electrophoresis and asymmetrical flow field flow fractionation
N2 - Two sets of polystyrene nanoparticles (PSNPs) with comparable core sizes but different carboxyl group densities were made and separated using asymmetric flow field flow fractionation (AF4), capillary electrophoresis (CE), and the off-line hyphenation of both methods. Our results revealed the significant potential of two-dimensional off-line AF4-CE hyphenation to improve the separation and demonstrated for the first time, the applicability of CE to determine the functional group density of nanoparticles (NPs). Compared to the result acquired with conductometric titration, the result obtained with synthesized 100 nm sized PSNPs revealed only a slight deviation of 1.7%. Commercial 100 nm sized PSNPs yielded a deviation of 4.6 %. For 60 nm sized PSNPs, a larger deviation of 10.6 % between both methods was observed, which is attributed to the lower separation resolution.
KW - Nanoparticle
KW - A4F
KW - Capillary electrophoresis
KW - Carboxyl group
PY - 2020
DO - https://doi.org/10.1016/j.chroma.2020.461392
VL - 1626
SP - 461392
PB - Elsevier B.V.
AN - OPUS4-51080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayat, Mehmet Emin
A1 - Nandayapa, Edgar R.
A1 - Tiebe, Carlo
A1 - Unger, Eva L.
A1 - List-Kratochvil, Emil J. W.
T1 - An operando spectroscopic examination of the influence of trace humidity on interdigital back contact metal halide perovskite solar cells
N2 - Controlling trace humidity is vital for both the fabrication and long-term stability of metal halide perovskite (MHP) solar cells. Relevant humidity levels are typically below 10 ppmV, especially in glovebox-based processing and in well-encapsulated devices. Even minute amounts during fabrication can influence crystallization, introducing defects and lowering efficiency. Over time, humidity accelerates degradation of the perovskite layer and internal interfaces, ultimately reducing operational lifetime. Probing these effects at low concentrations under operando conditions is therefore essential for advancing device performance and durability. In this work, we employed a high-precision transfer standard dew point hygrometer to investigate humidity levels between 5 and 35 ppmV in non-encapsulated MHP solar cells. To permit unobstructed water migration during operation, we fabricated interdigital back contact devices. Operando measurements revealed water transport through the perovskite layer and enabled quantification of outgassing. Under trace-humidified conditions, devices exhibited initial charge-carrier quenching, followed by gradual recovery. Notably, the photocurrent response to humidified nitrogen demonstrated that the MHP layer behaves fully reversibly within the explored timescale and across the investigated humidity levels and conditions. These findings establish a systematic operando framework for examining extrinsic stressors in perovskites and highlight opportunities for assessing passivation strategies.
KW - Metal halide perovskite
KW - IBC solar cells
KW - In operando
KW - Extrinsic stressors
KW - Fabrication and encapsulation
KW - Trace humidity
KW - Two-site Stern-Volmer
KW - Charge-carrier quenching
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657560
DO - https://doi.org/10.1039/D6TA01295G
SN - 2050-7496
SP - 1
EP - 16
PB - The Royal Society of Chemistry
CY - London
AN - OPUS4-65756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Parthasarathy, Thiyagaraj
A1 - Bhowmik, Aritra
A1 - Bhattacharya, Biswajit
A1 - Mishra, Manish Kumar
A1 - Ghosh, Soumyajit
T1 - Reversible twisting-induced crystalline–polycrystalline transformation in cyanoacrylate crystals
N2 - Centimeter-long single crystals of cyanoacrylate derivatives exhibit 1D elasticity, 2D plasticity and can be manually twisted and untwisted without any visible fractures, demonstrating exceptional mechanical flexibility and structural resilience.
KW - Weak intermolecular interactions
KW - Crystals
KW - Mechanical flexiblity
KW - Micro-focus Raman spectroscopy
KW - Single-crystal X-ray diffraction
PY - 2025
DO - https://doi.org/10.1039/D5CC05852J
SN - 1359-7345
VL - 62
IS - 1
SP - 264
EP - 267
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Soraya
A1 - Hülagü, Deniz
A1 - Bennet, Francesca
A1 - Carl, Peter
A1 - Flemig, Sabine
A1 - Schmid, Thomas
A1 - Schenk, J. A.
A1 - Hodoroaba, Vasile-Dan
A1 - Schneider, Rudolf
T1 - Electrochemical Immunomagnetic Ochratoxin A Sensing: Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine in Amperometric Assays
N2 - Electrochemical methods offer great promise in meeting the demand for user-friendly on-site devices for Monitoring important parameters. The food industry often runs own lab procedures, for example, for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with smart technologies. Enzyme-linked immunosorbent assays, with photometric detection of 3,3’,5,5’-tetramethylbenzidine (TMB),form a good basis for sensitive detection. To provide a straightforward approach for the miniaturization of the detectionstep, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. A stable electrode response to TMB could be achieved at pH 1 on gold electrodes. We created a smartphonebased, electrochemical, immunomagnetic assay for the detection of ochratoxin A in real samples, providing a solid basis forsensing of further analytes.
KW - Ochratoxin A
KW - Amperometry
KW - Cyclic voltammetry
KW - Electrochemistry
KW - Immunoassay
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530421
DO - https://doi.org/10.1002/celc.202100446
N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S.
VL - 8
IS - 13
SP - 2597
EP - 2606
AN - OPUS4-53042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - The Origin of Delayed Polymorphism in Molecular Crystals Under Mechanochemical Conditions
N2 - We show that mechanochemically driven polymorphic transformations can require extremely long induction periods, which can be tuned from hours to days by changing ball milling energy. The robust design and interpretation of ball milling experiments must account for this unexpected kinetics that arises from energetic phenomena unique to the solid state. Detailed thermal analysis, combined with DFT simulations, indicates that these marked induction periods are associated with processes of mechanical activation. Correspondingly, we show that the pre‐activation of reagents can also lead to marked changes in the length of induction periods. Our findings demonstrate a new dimension for exerting control over polymorphic transformations in organic crystals. We expect mechanical activation to have a much broader implication across organic solid‐state mechanochemistry.
KW - General Chemistry
KW - Catalysis
KW - Organic Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589219
DO - https://doi.org/10.1002/chem.202302150
SN - 0947-6539
SP - e202302150
PB - Wiley
AN - OPUS4-58921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Krause, Christina
A1 - Zorn, R.
A1 - Lohstroh, W.
A1 - Schneider, G. J.
A1 - Zamponi, M.
A1 - Holerer, O.
A1 - Frick, B.
A1 - Schönhals, Andreas
T1 - Complex molecular dynamics of a symmetric model discotic liquid crystal revealed by broadband dielectric, thermal and neutron spectroscopy
N2 - The molecular dynamics of the triphenylene-based discotic liquid crystal HAT6 is investigated by broadband dielectric spectroscopy, advanced dynamical calorimetry and neutron scattering. Differential scanning calorimetry in combination with X-ray scattering reveals that HAT6 has a plastic crystalline phase at low temperatures, a hexagonally ordered liquid crystalline phase at higher temperatures and undergoes a clearing transition at even higher temperatures. The dielectric spectra show several relaxation processes: a localized gamma-relaxation a lower temperature and a so called alpha-2-relaxation at higher temperatures. The relaxation rates of the alpha-2-relaxation have a complex temperature dependence and bear similarities to a dynamic glass transition. The relaxation rates estimated by hyper DSC, Fast Scanning calorimetry and AC Chip calorimetry have a different temperature dependence than the dielectric alpha-2-relaxation and follows the VFT-behavior characteristic for glassy dynamics. Therefore, this process is called alpha-1-relaxation. Its relaxation rates show a similarity with that of polyethylene. For this reason, the alpha-1-relaxation is assigned to the dynamic glass transition of the alkyl chains in the intercolumnar space. Moreover, this process is not observed by dielectric spectroscopy which supports its assignment. The alpha-2-relaxation was assigned to small scale translatorial and/or small angle fluctuations of the cores.
The neutron scattering data reveal two relaxation processes. The process observed at shorter relaxation times is assigned to the methyl group rotation. The second relaxation process at longer time scales agree in the temperature dependence of its relaxation rates with that of the dielectric gamma-relaxation.
KW - Discotic Liquid Crystals
PY - 2020
DO - https://doi.org/10.1039/c9sm02487e
VL - 16
IS - 8
SP - 2005
EP - 2016
PB - Royal Chemical Society
AN - OPUS4-50466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Lohstroh, W.
A1 - Zamponi, M.
A1 - Harrison, W.
A1 - Budd, P.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Molecular mobility of a polymer of intrinsic microporosity revealed by quasielastic neutron scattering
N2 - Quasielastic neutron scattering by employing a combination of time-of-flight and backscattering techniques is carried out to explore the molecular mobility of a polymer of intrinsic microporosity (PIM-1) at microscopic time scales in comparison with a high-performance polyimide. Molecular fluctuations can change the structure of the temporary network of micropores and open or close pathways for gas molecules. Therefore, the investigation might help to understand the selectivity of PIMs in gas separation processes. The performed neutron scattering experiments provide evidence for a low-temperature relaxation process, which was assigned to methyl group rotation. This methyl group rotation was analyzed in terms of jump diffusion in a three-fold potential. The analysis results in a fraction of methyl groups which are immobilized. For PIM-1 it was found that the fraction of immobilized methyl groups decreases with increasing temperature up to 350 K. At higher temperatures the number of immobilized methyl group increases gain due to an underlying relaxation process. This motional process on a somewhat larger length scale might lead to a reversible structural rearrangement which partially hinders the strongly localized methyl group rotation. In addition, it was found that the activation energy for the methyl group rotation for PIM-1 and the polyimide is significantly higher than for conventional polymers.
KW - Polymer of intrinsic microporosity
KW - Quasielastic neutron scattering
PY - 2020
DO - https://doi.org/10.1021/acs.macromol.0c00963
SN - 0024-9297
SN - 1520-5835
VL - 53
IS - 15
SP - 6731
EP - 6739
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-51147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knelles, J.
A1 - Wanner, C.
A1 - Schulz, F.
A1 - Freund, M.
A1 - Kolmangadi, Mohamed Aejaz
A1 - Baro, A.
A1 - Huber, P.
A1 - Schönhals, Andreas
A1 - Lachat, S.
T1 - Liquid crystalline hydrazones revisited: dipolar interactions vs hydrogen bonding affecting mesomorphic properties
N2 - In order to understand the role of dipolar interactions vs. H-bonding, a series of hydrazones were synthesised from 4-alkoxy-, 3,4-dialkoxy- or 3,4,5-trialkoxybenzaldehydes and phenyl, bromo- or nitrophenylhydrazine, respectively. Their mesomorphic properties were investigated by differential scanning calorimetry (DSC), polarising optical microscopy (POM), X-ray diffraction (WAXS, SAXS) and compared with known members. Only those hydrazones derived from 3,4,5-trisalkoxybenzaldehyde and either meta, meta-dinitro- or ortho, para-dinitrophenylhydrazine displayed hexagonal columnar mesophases. All other derivatives were non-mesomorphic, even when H-bonds were present. Dipole moments of the various nitro-substituted hydrazones were experimentally determined by dielectric measurements and supported by theoretical DFT calculations, which indicated that the mesophase formation is mostly governed by strong dipole moment and further enforced by intramolecular H-bonding.
KW - Discotic liquid crystals
PY - 2021
DO - https://doi.org/10.1080/02678292.2021.1873438
VL - 48
IS - 10
SP - 1382
EP - 1391
PB - Taylor & Francis
AN - OPUS4-52409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönhals, Andreas
T1 - Inelastic neutron scattering as a tool to investigate polymers of intrinsic microporosity for green membrane processes and electronic applications
N2 - Polymers with intrinsic microporosity are promising candidates for the active separation layer in green gas separation membranes and as active materials for electronic applicatons. Here, by means of inelastic neutron scattering, the vibrational density of states (VDOS) and the molecular mobility were investigated for PIM-1, the prototypical polymer with intrinsic microporosity. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid).
The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. In comparison to the Boson peak of Matrimid, that of PIM-1 is shifted to lower frequencies. This shift is discussed considering the microporous, sponge-like structure of PIM-1 as providing a higher compressibility at the molecular scale than for conventional polymers.
Elastic fixed window scans were measured on a neutron backscattering spectrometer to have an overview about the molecular dynamics at a time scale of ca. 1 ns. The temperature dependence of the estimated mean squared displacement shows a step-like increase in the temperature range from 100 K to 250 K indicating the onset of some molecular mobility. The nature of this motional process was analysed in detail by quasielastic neutron scattering combining Time-of-Flight and backscattering where the data are discussed with regard to both the q- and the temperature dependence.
T2 - Symposium on Large Scale Facilities
CY - Berlin, Germany
DA - 09.03.2020
KW - Polymer membranen
PY - 2020
AN - OPUS4-50546
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachenberger, Y. U.
A1 - Rosenkranz, Daniel
A1 - Kromer, C.
A1 - Krause, B. C.
A1 - Dreiack, N.
A1 - Kriegel, F. L.
A1 - Kozmenko, E.
A1 - Jungnickel, H.
A1 - Tentschert, J.
A1 - Bierkandt, F. S.
A1 - Laux, P.
A1 - Panne, Ulrich
A1 - Luch, A.
T1 - Nanomaterial Characterization in Complex Media - Guidance and Application
N2 - A broad range of inorganic nanoparticles (NPs) and their dissolved ions possess a possible toxicological risk for human health and the environment. Reliable and robust measurements of dissolution effects may be influenced by the sample matrix, which challenges the analytical method of choice. In this study, CuO NPs were investigated in several dissolution experiments. Two analytical techniques (dynamic light scattering (DLS) and inductively-coupled plasma mass spectrometry (ICP-MS)) were used to characterize NPs (size distribution curves) time-dependently in different complex matrices (e.g., artificial lung lining fluids and cell culture media). The advantages and challenges of each analytical approach are evaluated and discussed. Additionally, a direct-injection single particle (DI sp)ICP-MS technique for assessing the size distribution curve of the dissolved particles was developed and evaluated. The DI technique provides a sensitive response even at low concentrations without any dilution of the complex sample matrix. These experiments were further enhanced with an automated data evaluation procedure to objectively distinguish between ionic and NP events.
With this approach, a fast and reproducible determination of inorganic NPs and ionic backgrounds can be achieved. This study can serve as guidance when choosing the optimal analytical method for NP characterization and for the determination of the origin of an adverse effect in NP toxicity.
KW - Nanon
KW - Characterization
KW - SpICP-MS
KW - Matrix
KW - Dissolution
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572138
DO - https://doi.org/10.3390/nano13050922
VL - 13
IS - 5
SP - 1
EP - 19
AN - OPUS4-57213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mondal, Saikat
A1 - Prakash, Swayam
A1 - Riechers, Birte
A1 - Maaß, Robert
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Comprehensive Structure–Property Mapping of Tuned Mechanical Flexibility in Organic Cocrystals
N2 - Mechanically flexible crystals offer unique opportunities for adaptive materials, yet predictive control over their responses remains a major challenge. Here, we present a chemically unified series of 4-nitrophenol-based cocrystals, cocrystallized with bipyridyl linkers of varied geometries, to systematically map structure–property relationships. Subtle variations in interplanar angles and intermolecular interactions, such as π–π stacking and hydrogen bonding, enable tuning of mechanical responses ranging from brittle fracture to different extents of elastic bending and plastic bending or twistability. This design differs from previous strategies that relied primarily on van der Waals interactions or halogen bonding to impart mechanical compliance to organic crystals. Structural analysis, supported by energy framework calculations, explains the divergent mechanical behaviors. Notably, the studied cocrystal series spans all four canonical structure–property quadrants, manifested through mechanical flexibility, photoluminescence activity, or both. This systematic and comparative study highlights the delicate interplay between molecular packing and supramolecular interactions, providing structure–property correlations that inform emerging design principles for multifunctional crystalline materials for targeted applications.
KW - Aromatic compounds
KW - Crystals
KW - Deformation
KW - Flexibility
KW - Plastics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658364
DO - https://doi.org/10.1021/acs.cgd.5c01550
SN - 1528-7483
VL - 26
IS - 3
SP - 1370
EP - 1377
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-65836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Adapted ISO 3690 tests for quantifying realistic H contents for multi-layer manual welds of pipeline steels for an extended definition of HD classification
N2 - Pipeline steels are widely applicated for long-distance transmission pipelines. However, the welded joints of these steels can be susceptible to hydrogen-assisted cold cracking (HACC) during welding and after cooling especially in the heat-affected zone (HAZ). HACC in welds basically involves a critical combination of local, mutually dependent parameters consisting of: (1) a crack-critical microstructure; (2) sufficiently high mechanical stress; and (3) a diffusible hydrogen concentration (HD). In this context, thick-walled steel weld joints typically involve multi-layer welding with several passes. This leads to an effective, empirically known reduction in the global HD in the weld seam. This reduction is due to the repeated reheating of subsequently welded beads or layers, which reduces the local HD in the individual weld beads or layers. However, this has not yet been adequately quantified or described. Bead-on-plate tests, such as ISO 3690, cannot correctly reproduce the local HD distribution in individual welding passes (and thus, the global HD in the entire seam). Therefore, these tests lead to an extremely conservative evaluation of hydrogen ingress and the potential for "self-reduction" of HD due to increased interpass temperature during multi-layer welding, which has not yet been adequately addressed in the literature. Ideally, the local HD in each pass and the global (average) HD of the multi-layer weld would be known immediately after welding. For this reason, the study proposes an approach to address the local welding pass and layer-dependent, as well as global HD of multi-layer welds via a modified ISO 3690 test. To this end, representative welding parameter combinations for selected practical welding processes (e.g., SAW, GMAW, or SMAW) will be carried out as conventional bead-on-plate samples. These samples will be systematically extended by an increasing number of welding passes. Several sample series with an increasing number of beads or layers will be examined. Additionally, the initial HD is varied by methods such as targeted shielding gas variation (e.g., addition of hydrogen in GMAW) or moistened flux/coating (e.g., SAW/SMAW). Based on experimental data (temperature field measurements during welding and determination of temperature-dependent HD coefficients), a numerical hydrogen diffusion model is created. This model calculates the local HD (in the beads) and the HD across the weld cross-section. Additional variation calculations represent heat transfer conditions that were not recorded experimentally and their influence on HD distribution. Finally, we investigate the potential use of the modified ISO 3690 multi-layer geometry for application cases such as predicting the effectiveness and necessity of hydrogen removal heat treatment procedures for given welding parameter sets. Finally, an international round robin should be initiated once the concept has been successfully confirmed and verified.
T2 - IIW Intermediate Meeting, Com. XI
CY - Lahti, Finland
DA - 31.03.2026
KW - Hydrogen assisted cracking
KW - ISO 3690
KW - Multi-pass welding
KW - Diffusion
PY - 2026
AN - OPUS4-65825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - About the crystallization of cyclic and linear poly(L-lactide)s in alcohol-initiated and Sn(II)2-ethylhexanoate- catalyzed ROPs of L-lactide conducted in solution
N2 - 1-Hydroxymethylnaphtalene (HMN) or 11-bromoundecanol (BUND) were used as initiators and Sn(II) 2-ethylhexanoate (SnOct2) as catalyst for ROPs of L-Lactide (LA) at 115 °C in bulk or in 4 M and 2M solutions in toluene. The LA/In ratio, the LA/Cat ratio and the time were varied. The matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectra exclusively displayed peaks of linear chains, when the ROPs were conducted in bulk. But in contrast to reports in the literature, mixtures of linear and cyclic poly(L-lactide) (PLA), were obtained, when the ROPs were performed in solution. The intensity distribution of the mass peaks of cyclic PLAs displayed a “saw-tooth pattern” after annealing in contrast to the mass peak distribution of the liner chains. This new phenomenon indicated that cyclic PLAs and linear PLAs crystallized in separate crystals from the same reaction mixture. This conclusion was confirmed by fractionated crystallization from 2 M solution, which confirmed that the cyclic PLAs nucleate and crystallize faster than the linear chains.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring opening polymerization
KW - Crystallization
PY - 2023
DO - https://doi.org/10.1016/j.polymer.2023.125946
SN - 0032-3861
VL - 276
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-57308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Falkenhagen, Jana
T1 - Biobased and biogegradable polymers: Analytical challenges
N2 - The variability and heterogeneity in their structural composition is significant for nearly all synthetic and natural polymers. Beside molar mass also functionality type distribution, copolymer composition distribution and architectural features are responsible for changing the material properties.
A wide range of analytical techniques are available to get insight into these parameters. However, in most cases it is essential to combine different sophisticated techniques to get closer to actual structures and to avoid statistical averages.
Different liquid chromatographic separation modes and their coupling in a two-dimensional way (SEC, LCCC, HILIC, 2D-LC) in combination with suitable detection techniques (e.g. UV, RI, LS, IR, MALDI/ESI-MS) as well as techniques like BET, DCS, SEM/TEM were applied to make structural features visible.
A few aspects are discussed for structural different polylactides from various synthesis routes and their behavior in LC-MS. Moreover, some analytical results for technical lignins valorized by mechanochemical treatment or modified by functional polymers are presented.
T2 - 10th Intern. Symp. on the Separation and Characterisation of Natural and Synthetic Macromolecules (SCM-10)
CY - Amsterdam, Netherlands
DA - 01.02.2023
KW - Poly(lactides)
KW - Technical lignin
PY - 2023
AN - OPUS4-57002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Falkenhagen, Jana
T1 - Biobased and biodegradable Polymers: Analytical Challenges
N2 - The variability and heterogeneity in their structural composition is significant for nearly all synthetic and natural polymers. Beside molar mass also functionality type distribution, copolymer composition distribution and architectural features are responsible for changing the material properties.
A wide range of analytical techniques are available to get insight into these parameters. However, in most cases it is essential to combine different sophisticated techniques to get closer to actual structures and to avoid statistical averages.
Different liquid chromatographic separation modes and their coupling in a two-dimensional way (SEC, LCCC, HILIC, 2D-LC) in combination with suitable detection techniques (e.g. UV, RI, LS, IR, MALDI/ESI-MS) as well as techniques like BET, DCS, SEM/TEM were applied to make structural features visible.
A few aspects are discussed for structural different polylactides from various synthesis routes and their behavior in LC-MS.
T2 - 34th International Symposium on Polymer Analysis and Characterization (ISPAC)
CY - Stellenbosch, South Africa
DA - 24.04.2023
KW - Biobased polymers
KW - Biodegradable polymers
KW - Analytical techniques
PY - 2023
AN - OPUS4-60002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Falkenhagen, Jana
T1 - A Tribute to Harald –Lignin as biobased polymer-Trends and analytical issues
N2 - The presentation includes aspects of material design and characterization with a focus on lignin. Examples are the structural elucidation of lignosulfonates by means of two-dimensional chromatography, the mechanochemical degradation and functionalization of Kraft-Lignin with accompanying analytics. Future projects involving the incorporation of lignin into polymers will be presented.
T2 - Farewell Symposium for Prof. Harald Pasch; Polymer Analysis: Advancements in Characterization and Quantification
CY - Teltow, Germany
DA - 18.03.2024
KW - Lignin
KW - Biobased polymers
PY - 2024
AN - OPUS4-60003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kricheldorf, H. R.
T1 - Reversible Polycondensations and the Jacobson-Stockmayer Theory
N2 - Reversible polycondensations are polycondensations that include equilibration reactions at any stage of the process. Syntheses of Polyesters in bulk involving transesterification reactions and syntheses of polyamides in bulk involving transamidation are typical examples. In 1950, Jacobson and Stockmayer published a first theory of reversible polycondensations based on experimental studies with aliphatic polyesters.[1,2] They explained the reversibility by the reversible formation of cyclic oligomers and low molar mass polymers from an active chain end (so-called “back-biting”). The formation of cycles via end-to-end cyclization was excluded in agreement with Flory´s theory of irreversible polycondensations.[3] The reinvestigation of the Jacobson-Stockmayer experiments by the authors in combination with theoretical considerations shows that the JS theory is wrong. [4,5] It turned out that the experimental scenario is far from the reality. In real polycondensations, intermolecular equilibration is faster than “back-biting”, and end-to-end cyclization is quite normal. The revised theory of step-growth polymerization predicts that in the ideal case of 100% conversion, all reaction products are cycles, regardless, of whether the step-growth polymerization is reversible or not.
T2 - Polycondensation 2024
CY - Lyon, France
DA - 15.09.2024
KW - Polycondensation
KW - Cyclisation
KW - MALDI TOF MS
PY - 2024
UR - https://polycond-2024.sciencesconf.org/
AN - OPUS4-61070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Waste to value: upcycling PET bottles into MOFs using mechanochemistry
N2 - Single-use plastics are causing plastic pollution, and less than 10% of plastic waste gets recycled globally. Most of it ends up in landfills or gets incinerated in a highly unsustainable manner. Here, I will present a sustainable mechanochemical protocol for the chemical upcycling of waste polyethylene terephthalate (PET) bottles to porous UiO-66 metal-organic framework (MOF). We used in situ and ex situ characterization to gain a deep understanding of the underlying mechanochemical process leading to high crystallinity and -porosity UiO-66. Our results show the potential of mechanochemistry for the sustainable production of high-quality value-added materials such as UiO-66 from waste PET bottles.
T2 - 2024 Green Chemistry Gordon Research Conference
CY - Barcelona, Spain
DA - 31.07.2024
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2024
AN - OPUS4-62107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Alcohol-Initiated and SnOct2-Catalyzed Ring-Opening Polymerization (ROP) of L-Lactide in Solution: A Re-investigation
N2 - Alcohol-initiated ring-opening polymerizations (ROP) of L-lactide (LA) were studied in solution at 70 °C, whereupon the nature of the alcohol, the LA/initiator ratio, the LA/SnOct2 ratio and the time were varied. In contrast to literature, neat SnOct2 is catalytically active in THF and several aromatic but donor solvents, such as 1,3-dioxolane, dimethylformamide (DMF) or N-methyl pyrrolidone (NMP), strongly reduce the activity of SnOct2. In agreement with literature, no cycles were formed by neat SnOct2 at 70 °C in toluene, whereas almost complete cyclization occurs at 115 °C. This finding is attributed to strongly reduced mobility of the initially formed linear chains having one Sn-O-CH and one anhydride end group. Due to better solvation and enhanced mobility cyclization occurs in THF at 70 °C.
KW - Polylactide
KW - Ring-opening polymerization
KW - MALDI-TOF MS
KW - Transesterification
PY - 2023
DO - https://doi.org/10.1016/j.eurpolymj.2023.111822
SN - 0014-3057
SP - 1
EP - 18
PB - Elsevier
CY - New York, NY [u.a.]
AN - OPUS4-56818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chatti, Saber
T1 - Chemical modification of lignin by functional polymers: towards specific green phases for the adsorption of organic pollutants in water
N2 - Lignin is a highly aromatic low value biomass residue, which can be utilized for chemicals, fuels and materials production. In recent years, significant attention has focused on adsorber materials based on lignin. However, only 5% of the available lignin is exploited worldwide, thus significant opportunities for materials development still exist. Lignin has been vastly utilized as a feedstock for the synthesis of adsorbers for the removal of dyes and toxic organic molecules . To improve adsorption capacity, lignin can be chemically modified with oxygen-, nitrogen-, or sulfur-containing functional groups. Most frequently the phenolic groups of lignin were modified. In order to extend the application of lignin as adsorbers, we are especially interested in the chemical modification of this natural resource with a bio-based linear difluoro oligomers LOx (di- or monofunctional) or a heterocyclic monomer (Figure).
T2 - 12. Journees maghreb-europe. Matériaux et Applications aux Dispositifs et Capteurs
CY - Monastir, Tunisia
DA - 08.11.2022
KW - Lignin
KW - Biobased polymers
KW - Modification
PY - 2022
AN - OPUS4-56238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Effect of a High-Performance Modified Spray Arc MAG Process on Load-Oriented Repair of Old Steel Structures
N2 - Steel structures erected in the late 19th and early 20th centuries still constitute a substantial part of today’s technical infrastructure. A significant proportion of bridge and engineering structures have been in service for more than 80 or even 100 years and are subjected to continuously increasing traffic volumes, axle loads, and dynamic actions. In view of these rising service demands, load-oriented and structurally adequate repair strategies are essential to ensure long-term structural integrity while preserving the existing building stock in a sustainable manner.
As historical steel constructions were predominantly designed for riveted or bolted joints, the subsequent implementation of welded repair or strengthening measures represents a particular challenge. In addition to the specific material characteristics of old mild steels, welding-induced residual stresses and microstructural alterations must be carefully considered, as they can significantly affect load-bearing capacity and the overall structure performance. Consequently, repair concepts must not only restore geometry but also be adapted to the actual stress conditions and service requirements of the structure.
Against this background, the present study investigates MAG welding trials on mixed joints between old and modern structural steels. The groove opening angle was systematically varied between 50° and 30° in order to analyse the influence of joint geometry on weld metal volume, heat input, and the resulting residual stress state. Furthermore, advanced high-performance arc processes, such as a modified spray arc mode, were applied to enable controlled and reduced heat input. The objective is to minimise welding-induced residual stresses through process and joint design optimisation, thereby providing a technically sound and load-oriented repair strategy for existing old steel structures suitable for long-term service.
T2 - IIW Intermediate Meeting, Commission II-E
CY - Bangkok, Thailand
DA - 16.03.2026
KW - Historic mild steel
KW - Weldability
KW - High strength steel
PY - 2026
AN - OPUS4-65745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stolar, Tomislav
T1 - Mechanochemical Conversion Of Polyethylene Terephthalate Into Valuable Metal-organic Frameworks
N2 - Single-use plastics are causing plastic pollution, and less than 10% of plastic waste is recycled globally. Here, we present a sustainable mechanochemical protocol for converting post-consumer polyethylene terephthalate (PET) textile and bottles into the porous metal-organic framework (MOF) UiO-66. We used time-resolved in situ synchrotron powder X-ray diffraction and Raman spectroscopy to monitor the depolymerization of PET during ball milling with sodium and potassium hydroxide and water as a liquid additive. For synthesizing UiO-66, we focused on the better performing sodium hydroxide and optimized two distinct synthetic routes to produce high-quality UiO-66. Our results demonstrate the potential of mechanochemistry to enable more circular MOF synthesis using post-consumer PET waste.
T2 - International Conference on Sustainable Chemistry for Net Zero
CY - St. Andrews, United Kingdom
DA - 10.06.2025
KW - Mechanochemistry
KW - Plastic recycling
KW - Circular economy
PY - 2025
AN - OPUS4-63944
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Boccaccini, Aldo R.
A1 - Müller, Ralf
T1 - CuO nanocrystal formation during sintering of Cu-doped bioactive silicate glass powder surfaces
N2 - CuO nanocrystals were found to grow on polished, fractured, and glass powder particle surfaces of the copper-doped bioactive glass BG F3-Cu (44.8 SiO2–2.5 P2O3–35.5 CaO–6.6 Na2O–6.6 K2O–3 CaF2–1 CuO; mol%). Our results indicate that this CuO formation is driven by an inhibited Cu+/Cu2+ redox equilibrium. Since Cu2+ (CuO) is unstable during melting, a Cu+ (Cu2O) excess is frozen during cooling. Due to the limited oxygen availability, Cu + diffuses to the surface to get oxidized to Cu2+. Such oxidation, however, also occurs close beneath the melt surface during casting. As this reduces the CuO formation driving force, no CuO was found on the as-cast glass surface. The large low-temperature driving force of Cu oxidation also explains why CuO nanocrystals can easily grow during prolonged annealing well below the onset of the dominating surface crystallization of combeite during heating at 10 K/min. The minor influence of CuO surface crystal formation on sintering and overall crystallization allows for its control largely independent of the achievable densification and phase composition of the sintered BG compacts.
KW - Bioactive glass
KW - Copper oxide
KW - surface crystals
PY - 2026
DO - https://doi.org/10.1016/j.ceramint.2026.03.017
SN - 0272-8842
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-65764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Supramolecular Polymerization Induced by Confined Structural Water in Small Crown Macrocycle
N2 - Structural water, integral to biological systems, i.e., for protein stability and function, has rarely been explored in materials science. Supramolecular polymers, which assemble through non-covalent interactions, offer functionalities such as responsiveness and self-healing. Traditionally, in such systems water is considered as a solvent. Herein, a novel water-induced supramolecular polymer hydrogel is reported, formed by a single crown ether macrocycle with a selenoxide hydrogen bonding receptor and a hydrophobic selenium-substituted core. Structural water was confined in a nanosegregated three-dimensional architecture, maintaining water in a liquid-like state down to -80 °C. Unlike previous studies requiring multiple crown ether units for structural water formation, this single unit system effectively controls structural water and supramolecular polymerization. The presence of confined water was revealed through dielectric and Flash DSC experiments. The resulting hydrogel exhibits exceptional adhesion to hydrophilic surfaces, retaining strength at low temperatures. These findings demonstrate the significant role of a single macrocycle in governing water structure and functionality in supramolecular systems. An expansion of the understanding of water's role beyond a solvent has been achieved, showcasing its potential as a comonomer in material science, particularly in the development of responsive, adhesive supramolecular polymers and hydrogels.
T2 - Polydays 2024
CY - Berlin, Germany
DA - 30.09.2024
KW - Hydrogels
KW - Structural water
PY - 2024
AN - OPUS4-61658
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hernández García, María Amparo
T1 - Low-cost production of free-form optical components via standard LCD 3D printing for advanced opto-sensing
N2 - Nowadays, the use of complex optical elements is increasing also in applications such as miniaturized (bio)chemical opto-sensors. However, this can easily result in considerably high costs, time-consuming fabrication processes and the restricted availability of unconventional optics, which is especially problematic during the development phase of such devices. In this work, we propose LCD 3D printing as an alternative cost-effective technique, which is not only user-friendly but also free of design constrains enabling to fabricate free-form optics. A physical and spectroscopic characterization of six commercially available resins was performed together with the replication of optics and chemical sensing applications as a proof of concept. The optical transparency of the commercial mixtures was evaluated to discriminate the materials optically not suitable for the fabrication of transparent optical elements. Among the six resins, five were considered optimally transparent, with an optical transmittance >85% in the visible spectra range. However, fluorescence analysis of two of these commercial resins, assessed with an excitation-emission matrix (EEM), showed a high autofluorescence in the most common spectral working area of 410–600 nm. Therefore, only three commercial resins were considered for an in-depth evaluation. Ensuring that the refractive index (RI) of the resins complies with that of the most common optical materials, i.e., possesses a RI ~1.5 like polymers such as plexiglass or polycarbonate and glasses such as N-BK7, another important feature is an adequate surface quality of the printed objects. This could be accomplished with a dedicated post-treatment procedure allowing to reach a surface roughness of Rq = 0.07 μm, which agrees well with the values of common glass (Rq = 0.05 μm) and polymer lenses (Rq = 0.075 μm). To demonstrate the suitability of the 3D printed lenses, two different chemical sensors earlier published by us were replicated using the equivalent 3D printed lenses, i.e., a strip test for hydrocarbon detection using a 3D printed aspheric condenser and a microfluidic device for the determination of water chlorination using two cylindrical 3D printed lenses.[1, 2] Independent of the optical material used for the lenses, both assays exhibit similar calibration curves and results (see Figure 1 for one example), suggesting that LCD 3D printing is a suitable technique for the fabrication of free-form optics that allows to design, fabricate and test unconventional optics for miniaturized sensors in a much faster and distinctly less expensive manner.
T2 - How to develop a sensor? Academic Approaches vs. Industrial Interests (EU Training School)
CY - Kaiserslautern, Germany
DA - 18.09.2024
KW - 3D-printing
KW - Optics
KW - Photopolymerization
KW - Rapid prototyping
KW - Sensors
PY - 2024
AN - OPUS4-61444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Famy, A.
A1 - Agudo Jácome, Leonardo
A1 - Schönhals, Andreas
T1 - Effect of Silver Nanoparticles on the Dielectric Properties and the Homogeneity of Plasma Poly(acrylic acid) Thin Films
N2 - For the first time, structure−electrochemical relationships of thin films of a plasma-polymerized acrylic acid/carbon dioxide AA/CO2 (75/25%) copolymer modified by implanted silver nanoparticles are discussed. The pulsed plasma polymerization of AA/CO2 was utilized and adjusted to obtain a maximal amount of COOH Groups forming an almost uncross-linked polymer structure. The prepared polymer layer is rinsed by a silver nitrate solution to impregnate Ag+ ions. This step is followed by its reduction of Ag+ with NaBH4 as a chemical route in comparison to the reduction by sunlight as an ecofriendly photoreduction method. The chemical composition and morphology of the topmost surface layer of the AA/CO2 polymer thin film were investigated by X-ray photoelectron spectroscopy and atomic force microscopy. Moreover, the molecular mobility, conductivity, and thermal stability of the polymer layer were analyzed using broadband dielectric spectroscopy. The dielectric properties of the AA/
CO2 polymer thin film were studied in the presence of Ag+ ions or Ag0. It was found that a cross-linked polymer layer with a smooth surface and high conductivity was obtained in the presence of Ag+/ Ag0.
KW - Nanoparticles
PY - 2020
DO - https://doi.org/10.1021/acs.jpcc.0c06712
SN - 1932-7447
VL - 124
IS - 41
SP - 22817
EP - 22826
PB - ACS
AN - OPUS4-51468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silvestro, L.
A1 - Ruviaro, A. S.
A1 - Lima, G.
A1 - Durlo Tambara, Luís Urbano
A1 - Feys, D.
A1 - Kirchheim, A. P.
T1 - Rotational rheometry test of Portland cement-based materials - A systematic literature review
N2 - This study systematically reviews 62 papers on the use of rotational rheometry to assess the fresh state behavior of Portland cement-based materials. The research highlights the wide variation in test methods and aims to provide a comprehensive overview. Findings reveal that 50.0% of studies employed vane geometry, despite its limitations in providing transformation equations. Regarding dynamic shearing tests, 67.0% followed a consensus using a pre-shearing step and a step-wise routine with stabilization times ≥ 10 s. While the Bingham model is commonly used, the study emphasizes the importance of considering shear-thinning behavior in cementitious materials. Models like Herschel-Bulkley and modified Bingham may be more appropriate. This review offers insights into testing conditions for rotational rheometry of cementitious materials, serving as a foundation for future research in the field.
KW - Review
KW - Rheology
KW - Rheometry
KW - Rotational
KW - Cement
PY - 2024
DO - https://doi.org/10.1016/j.conbuildmat.2024.136667
SN - 0950-0618
VL - 432
SP - 1
EP - 14
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-60075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Materials design using chemical heuristics, workflows, and machine learning
N2 - Software implementations such as ChemEnv and LobsterEnv identify local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis (here using Crystal Orbital Hamilton Populations as computed with LOBSTER). Fully automated workflows and analysis tools now enable large-scale quantum-chemical bonding analysis. The first part of the lecture will demonstrate how these tools help develop new machine-learning models and intuitive understandings of material properties.
New universal machine-learned interatomic potentials, such as MACE-MP-0, have been developed. The second part of the lecture will showcase how these potentials, combined with DFT, can accelerate research. It will focus on the interplay between DFT and machine-learned interatomic potentials, presenting automated workflows for training, fine-tuning, and benchmarking these potentials, implemented in our software autoplex. Additionally, it will show how to train new interatomic potentials from scratch by exploring potential energy surfaces, with the potential to enhance current universal machine-learned potentials.
The lecture will also discuss the trend toward automation in computational materials science and our recent contributions
T2 - Group Seminar at the University of Toronto
CY - Online Meeting
DA - 18.07.2025
KW - Automation
KW - Magnetism
KW - High-throughput
KW - Amorphous Materials
KW - Phase Change Materials
KW - Phonons
PY - 2025
AN - OPUS4-63743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strobl, Dominic
T1 - Reduced Order Model for Temperature Field Simulation of Wire Arc Additive Manufacturing with Domain Mapping
N2 - Additive manufacturing (AM) has revolutionized the manufacturing industry, offering a new paradigm to produce complex geometries and parts with customized properties. Among the different AM techniques, the wire arc additive manufacturing (WAAM) process has gained significant attention due to its high deposition rate and low equipment cost. However, the process is characterized by a complex thermal history making it challenging to simulate it in real-time for online process control and optimization.
In this context, a reduced order model (ROM) using the proper generalized decomposition (PGD) method [1] is proposed as a powerful tool to overcome the limitations of conventional numerical methods and enable the real-time simulation of the temperature field of WAAM processes. These simulations use a moving heat source leading to a hardly separable parametric problem, which is handled by applying a novel mapping approach [2]. This procedure makes it possible to create a simple separated representation of the model, which allows to simulate multiple layers.
In this contribution, a PGD model is derived for the temperature field simulation of the WAAM process. A good agreement with a standard finite element method is shown. The reduced model is further used in a stochastic model parameter estimation using Bayesian inference, speeding up calibrations and ultimately leading to a calibrated real-time simulation.
T2 - MORTech 2023 - 6th International Workshop on Model Reduction Techniques
CY - Paris, France
DA - 22.11.2023
KW - Wire arc additive manufacturing
KW - Reduced order modelling
PY - 2023
AN - OPUS4-59105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schilling, Markus
A1 - Skrotzki, Birgit
T1 - Full dataset of several mechanical tests on an S355 steel sheet as reference data for digital representations
N2 - The dataset provided in this repository comprises data obtained from a series of characterization tests performed to a sheet of typical S355 (material number: 1.0577) structural steel (designation of steel according to DIN EN 10025-2:2019). The tests include methods for the determination of mechanical properties such as, e.g., tensile test, Charpy test and sonic resonance test. This dataset is intended to be extended by the inclusion of data obtained from further test methods. Therefore, the entire dataset (concept DOI) comprises several parts (versions), each of which is addressed by a unique version DOI.
The data were generated in the frame of the digitization project Innovationplatform MaterialDigital (PMD) which, amongst other activities, aims to store data in a semantically and machine understandable way. Therefore, data structuring and data formats are focused in addition to aspects in the field of material science and engineering (MSE). Hence, this data is supposed to provide reference data as basis for experimental data inclusion, conversion and structuring (data management and processing) that leads to semantical expressivity as well as for MSE experts being generally interested in the material properties and knowledge.
KW - S355 steel sheet
KW - Mechanical testing
KW - Tensile test
KW - Charpy test
KW - Microstructure analysis
KW - Digital representation
KW - Data management
KW - Data format
PY - 2022
DO - https://doi.org/10.5281/zenodo.6778336
PB - Zenodo
CY - Geneva
AN - OPUS4-55141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Grandel, Jonas
T1 - Harmonic phonon dataset
N2 - Phonon Dataset calculated with DFT PBE and the foundational MACE-MP-0b3 model.
The data are presented and discussed in the following publication: https://doi.org/10.1063/5.0297006
KW - Phonon
KW - MACE
KW - DFT
PY - 2025
UR - https://github.com/ACEsuit/mace-foundations
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-64747
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Management of Reference Data of Creep of Ni-Based Superalloys Exemplified for CMSX-6
N2 - The identification of process-structure-property relationships of materials inevitably requires the combination of research data from different measurements. Therefore, the concepts related to FAIR (findable, accessible, interoperable, reusable) data handling, increasingly reported in literature, are particularly important in the materials science and engineering domain. However, they have not yet been integrated into a single, overarching methodological framework, particularly for reference data. Here, we introduce such a framework, which covers data generation, documentation, handling, storage, sharing, data search and discovery, retrieval, and usage. Furthermore, we prototypically implement it using a real dataset with creep data of a single-crystal CMSX-6 Ni-based superalloy. The implementation is traceable and permanently accessible through open repositories. The individual elements considered in the framework ensure the functionality and usability of the data and, thus, the adherence to the FAIR principles. In conjunction with this, we present a definition for reference data of materials. Our definition underlines particularly the importance of a comprehensive documentation, e.g., on material provenance, data processing procedures, and the software and hardware used, including software-specific input parameters, as these details enable data users or independent parties to assess the quality of the datasets and to reuse and reproduce the results. Reference data that is managed according to the proposed framework can be used to advance knowledge in the materials science and engineering domain, e.g., by identifying new process-structure-property relations.
T2 - TMS 2025 Annual Meeting & Exhibition
CY - Las Vegas, NV, USA
DA - 22.03.2025
KW - Referenzdaten
KW - Creep
KW - Data schema
KW - NFDI-MatWerk
PY - 2025
AN - OPUS4-62849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
A1 - Schurig, M.
A1 - Schlums, H.
A1 - Madia, Mauro
A1 - Zerbst, Uwe
T1 - Bruchmechanische Bewertung der Integrität einer Turbinenscheibe bei Überdrehzahl
N2 - Turbinenscheiben sind thermisch und mechanisch hochbeanspruchte, sicherheitsrelevante Komponenten in Gasturbinen. Ihre Integrität wird in Bauteiltests unter Überdrehzahlbedingungen nachgewiesen. Kontext des Aufsatzes ist die Erarbeitung einer zusätzlichen Bewertungsebene auf der Grundlage von Versuchen unter monotoner Beanspruchung, die die Beanspruchung im Bauteil realistisch wiedergeben soll. Betrachtet wird ein halbelliptischer Riss, der bei der weiteren Ausbreitung als Umfangsriss wächst (rim peeling). Die Simulation dieser Stelle im Bauteil schließt die mechanische und thermische Beanspruchung sowie sie Dehnungsbehinderung ein. Letztere wird anhand zweier Parameter, der Spannungsmehrachsigkeit ℎ und des (allerdings modifizierten) Constraint-Parameters nach Newman, der die Spannungen über den plastisch verformten Bereich mittelt, bestimmt. Erwartungsgemäß zeigt sich, dass die höchste Dehnungsbehinderung weder an den Oberflächenpunkten, noch an den tiefsten Punkten, sondern an einer Stelle zwischen beiden auf der Rissfront auftritt. Als Versuchsgeometrie für die monotonen Tests soll eine Kreuzprobe mit wanddurchdringenden Rissen ausgehend von einer Innenbohrung dienen. Durch geeignete Wahl der Risstiefe sowie der in beiden Richtungen angreifenden Kräfte gelingt es, bauteiladäquate Zustände zu erzeugen.
T2 - 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 22.02.2022
KW - Bruchmechanik
KW - Struktur Integrität
KW - Turbinenscheibe
KW - Constraint
PY - 2022
SP - 13
EP - 22
AN - OPUS4-54403
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Experimentelle und numerische Untersuchung des Druckanschwingens von bruchmechanischen Proben aus konventionell und additiv gefertigtem 316L Stahl
N2 - Die Erzeugung rissschließfreier Anrisse in gekerbten bruchmechanischen Proben für anschließende Ermüdungsversuche kann durch eine zyklische Druckbelastung an der Kerbe erfolgen: Bei der Erstbelastung wird eine plastische Verformung an der Kerbspitze erzeugt, welche Zugeigenspannungen und damit eine risstreibende Kraft bei der folgenden zyklischen Druckbelastung hervorruft. Durch das Risswachstum kommt es zu einer Entspannung, bis der Riss schließlich arretiert, weil die effektive risstreibende Kraft auf den Schwellenwert abgesunken ist. Um Kurzrisswachstum in additiv, mittels pulverbettbasiertem Laserstrahlschmelzen (Laser Powder Bed Fusion - LPBF) gefertigtem AISI 316L Stahl und seinem konventionell erzeugten, warmgewalzten Pendant zu untersuchen, wurde dieses Verfahren im Rahmen der vorliegenden Arbeit genutzt. Im Falle des additiv gefertigten Materials kam es zu unerwartet langem Ermüdungsrisswachstum, bevor der Riss arretierte. Zur Ermittlung der Ursache erfolgte eine Messung der Eigenspannungsverteilungen mittels Neutronendiffraktion in der Kerbebene der additiv gefertigten Proben. Anschließend wurde ein Finite-Elemente-Modell zur Simulation des Ermüdungsrisswachstums in konventionellem und additiv gefertigtem Material implementiert. Im Rahmen dieses Vortrages wird insbesondere auf das Vorgehen bei der Simulation und auf die getroffenen Annahmen und Vereinfachungen eingegangen. Die Resultate werden mit den experimentellen Ergebnissen verglichen und das für die Simulation von Risswachstum genutzte Knoten-Freigabe-Verfahren (Node-Release), das Einbringen von Eigenspannungen als initiale Spannungen in der Simulation, und die Rechengrößen zur Quantifizierung der risstreibenden Kraft kritisch diskutiert.
T2 - 56. DVM Tagung "Bruchmechanik und Bauteilsicherheit"
CY - Kassel, Germany
DA - 20.02.2024
KW - PBF/LB
KW - Additive Fertigung
KW - Ermüdungsrisswachstum
KW - Druckanschwingen
KW - FEM
KW - Node-release
KW - Eigenspannungsmessung
KW - Neutronendiffraktion
PY - 2024
AN - OPUS4-59559
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Anwendung der zyklischen R-Kurven-Analyse zur Ermittlung des Kitagawa-Takahashi-Diagramms
N2 - Die ausgeprägte Langzeitfestigkeit eines Werkstoffes entspricht der maximalen Spannung, unterhalb derer alle ursprünglich wachstumsfähigen Mikrorisse arretieren. Für fehlerbehaftete Werkstoffe stellt das Kitagawa-Takahashi (KT)-Diagramm die Abhängigkeit der ausgeprägten Langzeitfestigkeit von der Defektgröße dar. Das KT-Diagramm kann mit großem Aufwand experimentell bestimmt oder durch verschiedene Modelle abgeschätzt werden. Solche Ansätze ergeben oft nichtkonservative Prognosen und berücksichtigen weder den Aufbau der Rissschließeffekte noch lokale Spannungen. In dieser Arbeit wird ein Kurzrissmodell auf Grundlage der zyklischen R-Kurve und des Rissarrestphänomens zur Abschätzung des KT-Diagramms vorgestellt. Die Abschätzungen werden mit experimentellen Daten validiert, die mit gekerbten Proben nach dem Treppenstufenverfahren ermittelt wurden.
T2 - AK-Bruch 2025
CY - Cologne, Germany
DA - 18.02.2025
KW - Langzeitfestigkeit
KW - KT-Diagramm
KW - Zyklische R-Kurven-Analyse
PY - 2025
AN - OPUS4-62598
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Thermografie-gestützte Untersuchung des Potentials des Kaltgasspritzens für die Reparatur zyklisch belasteter Bauteile
N2 - Die Reparatur mittels Kaltgasspritzen ist eine vielversprechende Alternative zum teuren Austausch fehlerbehafteter Bauteile in der Luft- und Raumfahrt. Durch die Beschleunigung von Metallpartikeln auf Überschallgeschwindigkeiten und die resultierende plastische Verformung der Partikel beim Aufschlag auf das Substrat ohne Aufschmelzen ermöglicht Kaltgasspritzen den schichtweisen Materialauftrag. Die Gewährleistung der Strukturintegrität reparierter Bauteile, insbesondere an der Schnittstelle zwischen dem Substrat und dem aufgetragenen Material, bleibt jedoch eine große Herausforderung.
Um dieses Problem zu lösen, wurden verschiedene Prozesse und Behandlungen untersucht, um die Festigkeit und Tragfähigkeit der Reparatur unter zyklischer Belastung zu optimieren. Röntgen-Computertomographie (XCT) ermöglicht die Analyse der Defekte in dem aufgetragenen Material und in der Grenzfläche. Die XCT kann jedoch nur mit hohem Aufwand in-situ während der mechanischen Prüfung eingesetzt werden. Im Gegensatz dazu kann die digitale Bildkorrelation (DIC) in-situ verwendet werden, da es sich um eine berührungslose Vollfeldtechnik handelt, die jedoch in erster Linie die durch das Prüfverfahren bedingten Verschiebungen an der Oberfläche erfasst.
Um die Entwicklung der Schädigung an der Grenzfläche zu überwachen, wurde die Infrarot-Thermografie (IRT) parallel zur DIC bei der Zug- und Ermüdungsprüfung von reparierten Al6061 Proben eingesetzt. Es wurde eine gekühlte IRT-Kamera mit hoher Bildrate verwendet, die Nachverarbeitung erfolgte mittels Lock-in IRT. Mit Hilfe von IRT war es möglich, die frühe Schadensentstehung an der Grenzfläche des Substrats zu erkennen und das Risswachstum zu verfolgen. Die Bruchflächen bestätigten, dass die identifizierten Merkmale an der Grenzfläche lagen. Es werden Ergebnisse eines Vergleichs von DIC und IRT aus Ermüdungs- und Zugversuchen vorgestellt.
T2 - Werkstoffprüfung 2025
CY - Dresden, Germany
DA - 27.11.2025
KW - Additive Fertigung
KW - Kaltgasspritzen
KW - Thermografie
KW - Digitale Bildkorrelation
KW - Ermüdungsfestigkeit
PY - 2025
AN - OPUS4-64998
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Cyclic Deformation Behavior of Laser Powder Bed Fused Stainless Steel 316L Role of the Manufacturing Induced Cell Structure
N2 - The cyclic deformation behavior of an austenitic 316L stainless steel produced by laser powder bed fusion in two heat treated conditions and featuring a low defect population is presented. Strain controlled push/pull tests were performed between room temperature and 600 °C. The PBF‑LB/M/316L exhibits an initial cyclic hardening, followed by a cyclic softening. The grade of softening decreases (i) with increasing test temperature and (ii) after a partial dissolution of its dislocation substructure through heat treatment. The deformation behavior and its dependency on test temperature and heat-treated/microstructural condition are attributed to the slip character and related changes. With either a partially dissolved dislocation substructure or increasing test temperature the material exhibits typical wavy slip characteristics. In the opposite case, the deformation mechanism seems to be rather planar dislocation slip as the formation of slip planes spanning through entire grains was observed, seemingly acting as pathways of easy dislocation movement.
T2 - TMS 2025
CY - Las Vegas, Nevada, US
DA - 23.03.2025
KW - AGIL
KW - Additive Fertigung
KW - Low-Cycle-Fatigue
KW - Mikrostruktur
KW - 316L
PY - 2025
AN - OPUS4-64855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Radners, J.
A1 - Han, Ying
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Aluminium Hochtemperaturermüdung
N2 - Die hohen Betriebstemperaturen während des Einsatzes von Radialverdichterrädern in Abgasturboladern führen zu einer Änderung der ursprünglich eingestellten Mikrostruktur in der warmfesten Aluminiumlegierung EN AW-2618A (Überalterung). Grund dafür sind thermische Belastungen, die nahe der Aushärtetemperatur liegen und diese kurzzeitig sogar überschreiten können. Die Alterungsmechanismen wurden zusammen mit den Themen niederzyklische (LCF) und thermomechanische Ermüdung (TMF) sowie Kriechen bis max. 190 °C in vorangegangenen Forschungsvorhaben untersucht. Kaum untersucht war bisher das Verhalten der Legierung unter hochzyklischer Beanspruchung (HCF) sowie der Einfluss von Kerben und Lastkollektiven. Da zukünftig mit weiter steigenden Betriebstemperaturen für Radialverdichter zu rechnen ist, wurde in diesem Forschungsvorhaben das HCF-Verhalten bei 230 °C untersucht und somit bei einer Prüftemperatur, die deutlich oberhalb der Aushärtetemperatur liegt. Das Ziel des Projektes war der Aufbau einer geeigneten experimentellen Datenbasis, das Verständnis der relevanten mikrostrukturellen Prozesse sowie die Weiterentwicklung und Anpassung geeigneter Modelle und Bewertungsmethoden.
Das experimentelle Untersuchungsprogramm umfasste neben einer Basischarakterisierung des HCF-Verhaltens am Ausgangszustand T61 gezielte mechanische Versuche zur Isolierung der Einflussfakto-ren Mittelspannung (𝑅 = −1, 𝑅 = 0,1), Werkstoffüberalterung (T61, 10 h/230 °C, 1000 h/230 °C), Prüftemperatur (20 °C, 230 °C), Prüffrequenz (0,2 Hz, 20 Hz) sowie Kerbwirkung und variable Amplituden. Darauf aufbauend wurden die in den vorangegangenen Projekten entwickelten Modelle und Bewertungsmethoden angepasst und weiterentwickelt, um die genannten thermischen und mechanischen Belastungen in der Lebensdauerbewertung abzubilden.
KW - HCF
KW - Aluminium
KW - EN AW-2618A
KW - Ermüdung
PY - 2023
SP - 1
EP - 111
CY - Frankfurt am Main
AN - OPUS4-57850
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhu, Jiangchao
A1 - Madia, Mauro
A1 - Schurig, Michael
A1 - Fedelich, Bernard
A1 - Schlums, Hartmut
A1 - Zerbst, Uwe
T1 - Burst speed assessment of aero-engine turbine disk based on failure assessment diagram and global stability criterion
N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on production-similar disks. While these tests provide, on the one hand, a reliable definition of the critical conditions for real components, on the other hand they represent a relevant cost item for engine manufacturers. The aim of this work is to present two alternative burst speed assessment methods under development based on the Failure Assessment Diagram (FAD) and a global stability criterion, respectively. In the scope of the fracture mechanics assessment, the failure modes hoop-burst and rim-peeling are investigated with semicircular surface cracks modelled at the critical regions on the turbine disk. The comparison of the predicted critical rotational speed shows good agreement between the assessment methods.
KW - Global stability criterion
KW - Fracture mechanics
KW - Burst
KW - Turbine disk
PY - 2023
DO - https://doi.org/10.1016/j.engfracmech.2022.109005
SN - 0013-7944
VL - 277
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-56736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Ermüdung von additiv gefertigtem Stahl AISI 316L: Zyklische plastische Verformung
N2 - Das zyklische plastische Verformungsverhalten von additiv gefertigtem Edelstahl AISI 316L wurde in dehnungsgeregelten Kurzzeitfestigkeitsversuchen (LCF-Versuchen) untersucht. Dabei wurden zwei Wärmebehandlungszustände betrachtet: Beim ersten Zustand war die fertigungsbedingte zelluläre Struktur vorhanden, während sie durch die zweite Wärmebehandlung aufgelöst wurde. Untersuchungen im Transmissions-Elektronen-Mikroskop (TEM) zeigten, dass die zyklische Verformung die Zellstruktur lokal zerstörte und Gleitbänder entstanden, was die Entfestigung in diesem Fall erklärt. Für Material ohne Zellstrukturen resultierten nach zyklischer Verformung ähnliche Versetzungsstrukturen wie in konventionell gefertigtem (warmgewalzten) Material.
T2 - OVGU-Kolloquium (BMDK des IWF)
CY - Magdeburg, Germany
DA - 23.06.2022
KW - Additive Fertigung
KW - Kurzzeitfestigkeit
KW - Mikrostrukturentwicklung
KW - Versetzungsstrukturen
KW - TEM
PY - 2022
AN - OPUS4-56789
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stephan-Scherb, Christiane
T1 - Elucidation of competitive oxidation/sulfidation reactions on binary ferritic alloys
N2 - Ferritic-austenitic chromia-forming alloys are frequently used as boiler tubes and heat exchanger materials for fossil-,biomass, and co-fired power plants. In all applied environments several strongly corrosive gaseous species such as CO2, SO2, SO3, H2O, O2 exist, causing materials degradation by high-temperature corrosion. The elucidation of degradation mechanisms introduced by multiple gases is challenging due to the presence of different oxidizing agents contributing to the competing reactions for oxidation, sulfurization or carburization. The degradation processes can be divided into initial stages, a transitional stage and the further proceeding steady-state oxidation reaction. Especially the long-term steady-state oxidation and further materials’ life-time are strongly dependent on the initial stages. The adsorption and absorption of the reactive species at the alloy surface and the growing oxide in the initial reaction is further influenced by dissociation and re-reactions of the gas phase molecules. To understand these mechanisms from a fundamental point of view in more detail, dedicated experiments and advanced characterization techniques on various length scale need to be applied. Real-time approaches using highly energetic synchrotron X-ray diffraction showed a high potential to enlighten competitively mechanisms by following the corrosion reactions in-situ in the environment they occur. Despite various other thin film characterization techniques, time of flight secondary ion mass spectroscopy (ToF-SIMS) is a powerful tool to visualize light atoms or labeled isotopes enabling the Differentiation between different oxidizing species. It was especially shown to be applicable in challenging atmospheres containing KCl deposits or in CO/CO2/O2 environments. The present study analyses the competing oxidation/sulfidation process in a humid atmosphere on two ferritic alloys with 2 and 9 % in weight chromium by in situ energy dispersive X-ray diffraction (EDXRD) and comparative tube furnace exposure using S16O2 and H2 18O atmosphere.
T2 - Conference on High Temperature Corrosion and Protection of Materials HTCPM 2021
CY - Online Meeting
DA - 29.03.2021
KW - Oxidation
KW - High Temperature Corrosion
KW - Ferritic Alloys
KW - SIMS
KW - EDXRD
PY - 2021
AN - OPUS4-52363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schönherr, J. A.
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Geilen, M. B.
A1 - Klein, M.
A1 - Oechsner, M.
T1 - Robust determination of fatigue crack propagation thresholds from crack growth data
N2 - The robust determination of the threshold against fatigue crack propagation DKth is of paramount importance in fracture mechanics based fatigue assessment procedures. The standards ASTM E647 and ISO 12108 introduce operational definitions of DKth based on the crack propagation rate da/dN and suggest linear fits of logarithmic DK– da/dN test data to calculate DKth. Since these fits typically suffer from a poor representation of the actual curvature of the crack propagation curve, a method for evaluating DKth using a nonlinear function is proposed. It is shown that the proposed method reduces the artificial conservativeness induced by the evaluation method as well as the susceptibility to scatter in test data and the influence of test data density.
KW - Fatigue crack propagation threshold
KW - ISO 12108
KW - ASTM E647
KW - Data evaluation methods
KW - Experimental determination
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552153
DO - https://doi.org/10.3390/ma15144737
SN - 1996-1944
VL - 15
IS - 14
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-55215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Kriech- und Bruchverhalten von additiv hergestelltem austenitischem Stahl 316L. Vergleich zum konventionellen Werkstoff.
N2 - Eine kritische Aufgabe im Rahmen der Etablierung von Prozess-Struktur-Eigenschafts-Performance-Beziehungen bei der additiven Fertigung (AM) von Metallen ist die Ermittlung von zuverlässigen und gut dokumentierten Kennwerten zum Materialverhalten sowie das Schaffen von Wissen über die Struktur-Eigenschafts-Korrelation. Schließlich ist dies die Grundlage für die Entwicklung gezielterer Prozessoptimierungen und zuverlässigerer Lebensdauer-Vorhersagen. In diesem Zusammenhang zielt dieser Beitrag darauf ab, Daten und Erkenntnisse über das Kriechverhalten des austenitischen Edelstahls 316L zu liefern, der mittels Laser-Powder-Bed-Fusion (L-PBF) hergestellt wird. Um dieses Ziel zu erreichen, wurden Proben aus konventionellem warmgewalztem sowie AM-Material gemäß den bestehenden Normen für konventionelles Material geprüft und vor und nach dem Versagen mikrostrukturell charakterisiert. Die Probekörper wurden aus einzelnen Blöcken des AM-Materials gefertigt. Die Blöcke wurden mit einer Standard-Scan- und Aufbaustrategie hergestellt und anschließend wärmebehandelt. Das Kriechverhalten wird anhand der Kriechlebensdauer und ausgewählter Kriechkurven und Kennwerte beschrieben und vergleichend bewertet. Der Einfluss von Defekten und Mikrostruktur auf das Materialverhalten wird anhand von zerstörenden und zerstörungsfreien Auswertungen an ausgewählten Proben analysiert. Der AM-Werkstoff zeigt kürzere Kriechlebensdauern, erreicht das sekundäre Kriechstadium deutlich schneller und bei geringerer Dehnung und weist eine geringere Kriechduktilität im Vergleich zu seinem konventionellen Gegenstück auf. Das Kriechschädigungsverhalten des AM-Werkstoffs ist eher mikrostruktur- als defektgesteuert und ist durch die Bildung intergranularer Kriechrisse gekennzeichnet. Als kritische Merkmale werden die Versetzungsdichte sowie die Versprödung der Korngrenzen identifiziert. Die Mikro-Computertomographie (µCT) erweist sich als Alternative zur Metallographie, um die Kriechschädigung zu analysieren.
T2 - Sitzung des DGM-Arbeitskreises Mechanisches Werkstoffverhalten bei hoher Temperatur
CY - Online meeting
DA - 07.10.2020
KW - 316L
KW - Kriechen
KW - Additive Fertigung
KW - Mikrostruktur
KW - Mikro-Computertomographie
PY - 2020
AN - OPUS4-51824
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
A1 - Schartel, Bernhard
A1 - Lin, Xuebao
A1 - Tan, Yi
A1 - Schoch, R.
A1 - Lang, M.
A1 - Tröppner, O.
A1 - Bosse, M.
ED - Ziegahn, K.-F.
T1 - Untersuchung der Witterungsbeständigkeit komplexer Funktionalitäten von Polymerwerkstoffen durch künstliche Bewitterung: Flammschutz
N2 - In den letzten Jahrzehnten wurde die Degradation der polymeren Matrix von flammgeschützten Polymeren eingehend untersucht. Erst in den letzten Jahren jedoch hat sich die Frage der Lebensdauer der Funktionalität des Flammschutzes selbst als wichtige Fragestellung herauskristallisiert, z.B. bei Kabeln. Deshalb sollte diese Fragestellung durch systematisch-variierte künstliche Klima- und Bewitterungstests an flammgeschützten Polymerwerkstoffen untersucht werden.
T2 - 50. Jahrestagung der Gesellschaft für Umweltsimulation (GUS)
CY - Online meeting
DA - 23.03.2022
KW - Flammschutz, Witterungsbeständigkeit, Langzeitbeständigkeit, UV, E&E
PY - 2022
SN - 978-3-9818507-7-2
VL - 50
SP - 143
EP - 148
CY - Pfinztal (Berghausen)
AN - OPUS4-54543
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Influence of Ultrasonic-Assisted Milling on Surface Integrity of Additively Manufactured Components Using DED-Arc/GMAW
N2 - Additive manufacturing (AM) is increasingly used for producing complex metallic com-ponents. Subsequent machining is essential to achieve final geometries and surface conditions. The resulting surface integrity, particularly the near-surface residual stress state, plays a crucial role in component performance and fatigue life. This study inves-tigates the potential of ultrasonic-assisted milling (USAM), a hybrid machining process, to improve surface integrity and machinability compared to conventional milling (CM). Three materials were investigated, two difficult-to-cut materials CoCr26Ni9Mo5W and FeNi36 and a low-alloy steel S355J2C. The CoCr26Ni9Mo5W and FeNi36 were addi-tively manufactured via DED-Arc and then machined with varying cutting speeds and feed rates within a Design of Experiments. USAM exhibited enhanced machinability and surface integrity, particularly at low cutting speeds, by reducing cutting forces up to 40% and shifting near-surface residual stresses from tensile to compressive. For S355J2C, USAM reduced cutting forces by approximately 45% and induced surface-near compressive residual stresses up to approximately -700 MPa, leading to a 11% higher fatigue strength compared to CM. These findings highlight the advantages of ultrasonic assistance in post-AM machining, offering enhanced fatigue performance and surface quality for various metallic materials.
T2 - 4th International Conference on Advanced Joining Processes 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - Surface integrity
KW - Fatigue strength
KW - Residual stress
PY - 2025
AN - OPUS4-65051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Serrano-Munoz, Itziar
T1 - Influence of microstructure and residual stress state on the fatigue behaviour of a PBF-LB/M AlSi10Mg alloy
N2 - The high cooling rates (~106 K/s) occurring during Laser Powder Bed Fusion (PBF-LB/M) of AlSi10Mg induce to the formation of a fine nanometric silicon network in the as-built condition. Such unprecedented microstructure enhances the mechanical strength when compared to equivalent as-cast materials. Nevertheless, PBF-LB/M also leads to high magnitude residual stress (RS) due to the extreme localized temperature gradients. The presence of RS can be detrimental to the fatigue life of engineering components, and great efforts are focused on understanding their generation and evolution after post-process heat treatments. Typically, T6 heat treatments are used to mitigate RS and improve mechanical performances by Mg2Si precipitation during ageing at 160-180°C. Nevertheless, the solutionizing at 500-540°C vanishes the fine silicon network, leading to the formation of micrometric (average of ~2-5 µm) polygonal Si particles, similar to those observed in T6 heat-treated Al-Si cast materials. Therefore, the aim of this work is to evaluate the ability of two so-called low temperature heat treatments (i.e., at 265°C and 300°C) to mitigate RS while retaining the fine as-built microstructure inherent to PBF-LB/M AlSi10Mg. The fatigue behavior of the as-built material is subsequently compared to the two low temperature conditions.
T2 - LightMat 2023
CY - Trondheim, Norway
DA - 21.06.2023
KW - AlSi10Mg
KW - Fatigue crack propagation
KW - Residual stress
KW - Post processing heat treatment
PY - 2023
AN - OPUS4-57807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Han, Ying
T1 - Hochtemperaturermüdung der Aluminiumlegierung EN AW-2618A
N2 - Abgasturbolader tragen wesentlich zur Effizienzsteigerung moderner Verbrennungsmotoren bei. Die im Abgasturbolader eingesetzten Radialverdichterräder werden überwiegend aus der warmfesten ausscheidungsgehärteten Aluminiumlegierung EN AW-2618A hergestellt.
Die Anforderungen an die Radialverdichterräder steigen und die Betriebszeiten verlängern sich. Für eine optimale Auslegung des Bauteils ist unter anderem die Kenntnis des Ermüdungsverhaltens dieser Legierung erforderlich. Es ist bekannt, dass sich die Mikrostruktur dieser Legierung während des Betriebs vergröbert und dadurch die Festigkeit abnimmt. Das niederzyklische Ermüdungsverhalten für den Ausgangszustand des Werkstoffs und Prüftemperaturen bis 190 °C ist bereits gut untersucht. Für das hochzyklische Ermüdungsverhalten, insbesondere für Prüftemperaturen über 190 °C, liegen jedoch nur wenige Ergebnisse vor. Das Ziel dieser Arbeit ist es daher, die Datenbasis hinsichtlich der hochzyklischen Ermüdungslebensdauer bei erhöhten Prüftemperatur zu vervollständigen und das Werkstoffverhalten sowie die Schädigungsmechanismen zu charakterisieren.
Zu diesem Zweck wurden axiale Ermüdungsversuche an glatten Proben durchgeführt.
Neben dem T61-Ausgangszustand für eine Basischarakterisierung wurden zwei überalterte Zustände, jeweils bei 230 °C für 10 h und 1000 h ausgelagert und anschließend geprüft, um den Einfluss der Überalterung auf die Ermüdungslebensdauer zu erfassen. Die Auslagerungstemperatur von 230 °C der überalterten Zustände liegt deutlich über der Aushärtungstemperatur von 195 °C des T61-Zustands, was zu Veränderungen der optimal eingestellten Mikrostruktur führt, die sich wiederum in den mechanischen Eigenschaften widerspiegeln. Mit der Überalterungszeit von 10 h wurde ein Zustand untersucht, der einem Härteniveau entspricht, der bei Bauteilrückläufern nach Langzeitbetrieb beobachtet wurde und mit der Überalterungszeit von 1000 h wurden die Werkstoffgrenzen ermittelt. Zusätzlich wurde mittels Transmissionselektronenmikroskopie (TEM) die Vergröberung der festigkeitssteigernden S-Phase untersucht. Der Einfluss der Prüftemperatur auf die Ermüdungslebensdauer wurde durch Versuche bei 230 °C untersucht. Die Ermüdungsversuche wurde durch fraktographische Untersuchungen ergänzt und ausgewählte Ermüdungsversuche wurden mit zerstörungsfreien Prüfmethoden begleitet, um die Schädigung mit zunehmender Zyklenzahl dazustellen.
Die Ergebnisse dieser Untersuchungen zeigen eine kürzere Ermüdungslebensdauer für die längere Überalterungszeit bei gleicher Spannungsamplitude. Die Transmissionselektronenmikroskopie zeigt, dass der mittlere Radius der S-Phase nach einer Überalterungszeit von 10 h um den Faktor 2,3 und nach 1000 h um den Faktor 2,7 im Vergleich zum Ausgangszustand zunimmt. Eine Erhöhung der Prüftemperatur auf 230 °C führt bei gleicher Spannungsamplitude zu einer Verkürzung der Ermüdungslebensdauer im Vergleich zu Raumtemperatur. Die fraktographischen Untersuchungen zeigen, dass unabhängig vom Werkstoffzustand und der Prüftemperatur die Rissinitiierung überwiegend an der Probenoberfläche oder in der Nähe der Primärphasen erfolgt. Das Risswachstum mit zunehmender Zyklenzahl kann mit der Replika-Methode erfolgreich abgebildet werden. Die
Abbildung des Risses in der noch nicht gebrochenen Probe ist auch mit der Computertomographie möglich.
KW - Aluminiumlegierung
KW - EN AW-2618A
KW - Ermüdung
KW - HCF
KW - Mikroskopie
KW - Fraktographie
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615288
DO - https://doi.org/10.14279/depositonce-21381
SP - 1
EP - 109
PB - Depostit Once
CY - Berlin
AN - OPUS4-61528
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Hanke, Thomas
A1 - Skrotzki, Birgit
T1 - Semantic Representation of Low‐Cycle‐Fatigue Testing Data Using a Fatigue Test Ontology and ckan.kupferdigital Data Management System
N2 - Addressing a strategy for publishing open and digital research data, this article presents the approach for streamlining and automating the process of storage and conversion of research data to those of semantically queryable data on the web. As the use case for demonstrating and evaluating the digitalization process, the primary datasets from low‐cycle‐fatigue testing of several copper alloys are prepared. The fatigue test ontology (FTO) and ckan.kupferdigital data management system are developed as two main prerequisites of the data digitalization process. FTO has been modeled according to the content of the fatigue testing standard and by reusing the basic formal ontology, industrial ontology foundry core ontology, and material science and engineering ontology. The ckan.kupferdigital data management system is also constructed in such a way that enables the users to prepare the protocols for mapping the datasets into the knowledge graph and automatically convert all the primary datasets to those machine‐readable data which are represented by the web ontology language. The retrievability of the converted digital data is also evaluated by querying the example competency questions, confirming that ckan.kupferdigital enables publishing open data that can be highly reused in the semantic web.
KW - Accessible
KW - CKAN
KW - Interoperable
KW - Digitalizations
KW - Ontologies
KW - Reusable data
KW - Fatigue testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604991
UR - https://onlinelibrary.wiley.com/doi/10.1002/adem.202400675
DO - https://doi.org/10.1002/adem.202400675
SN - 1527-2648
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-60499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-throughput and data-driven approaches for materials understanding and design
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties.[1] Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available.[2,3] Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale.[3,4] The lecture will demonstrate how our tools, which assess local atomic environments and perform automatic bonding analysis, help to develop new machine-learning models and a new intuitive understanding of materials.[5,6]
Beyond this, the general trend toward automation in computational materials science and some of our recent contributions will be discussed.[7–11] The focus will be especially on the interplay of DFT and machine-learned interatomic potentials will present new fully automated workflows for training and benchmarking machine-learned interatomic potentials with force predictions accurate enough to compute harmonic phonons in very good agreement with DFT. Semi-automated fine-tuning of existing ML models for phonon properties will also be discussed.
T2 - XXIV Chilean Physics Symposium
CY - Temucu, Chile
DA - 20.11.2024
KW - Automation
KW - Machine Learning
KW - Chemically Complex Materials
KW - Machine-Learned Interatomic Potentials
KW - Finetuning
PY - 2024
AN - OPUS4-61749
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Elektronenstrahl schweißt additiv gefertigte Nickel-Superlegierungen
N2 - Die Additive Fertigung ist ideal zur Herstellung und Reparatur komplexer Bauteile aus hochfesten Werkstoffen. Doch es fehlen Fügeverfahren, die Heißrisse vermeiden. Die Lösung heißt
Elektronenstrahl.
KW - Additive Fertigung
PY - 2021
SP - 1
EP - 6
AN - OPUS4-53979
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Creep and fracture behavior of conventionally and additively manufactured stainless steel 316L
N2 - A critical task within the frame of establishing process-structure-property-performance relationships in additive manufacturing (AM) of metals is producing reliable and well-documented material behavior’s data and knowledge regarding the structure-property correlation, including the role of defects. After all, it represents the basis for developing more targeted process optimizations and more reliable predictions of performance in the future. Within this context, this contribution aims to close the actual gap of limited historical data and knowledge concerning the creep behavior of the widely used austenitic stainless steel 316L, manufactured by Laser-Powder-Bed-Fusion (L-PBF). To address this objective, specimens from conventional hot-rolled and AM material were tested under application-relevant conditions according to existing standards for conventional material, and microstructurally characterized before and after failure. The test specimens were machined from single blocks from the AM material. The blocks were manufactured using a standard scan and build-up strategy and were subsequently heat-treated. The creep behavior is described and comparatively assessed based on the creep lifetime and selected creep curves and characteristic values. The effect of defects and microstructure on the material’s behavior is analyzed based on destructive and non-destructive evaluations on selected specimens. The AM material shows shorter creep lives, reaches the secondary creep stage much faster and at a lower strain, and features lower creep ductility compared to its conventional counterpart. The creep damage behavior of the AM material is more microstructure than defect controlled and is characterized by the formation and accumulation of single intergranular damage along the whole volume. Critical features identified are the grain morphology and the grain-boundary as well as the dislocation’s density. Micro-computed tomography (µCT) proves to be an alternative to metallography to analyze the creep damage.
T2 - ASTM International Conference on Additive Manufacturing 2020
CY - Online meeting
DA - 16.11.2020
KW - 316L
KW - Creep behavior
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Microstructure
PY - 2020
AN - OPUS4-51823
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Framework for Curation and Distribution of Reference Datasets on the Example of Creep Data of Ni- Based Superalloys
N2 - This presentation introduces our current effort to develop a best practice framework for generating and distributing MSE reference datasets using creep data of Ni-based superalloys as an example, building on previous approaches. Such reference datasets can be used in the verification of testing equipment or to compare experimental or simulation results among different laboratories or collaborative centers. Our framework concept, for reference data, includes the generation of the data along with an agreement on the necessary metadata, considering the intended usage, and the integration into an easily accessible digital infrastructure to annotate and discover/distribute the datasets using a metadata schema accordingly aligned to a domain ontology.
T2 - International Materials Science and Engineering Congress - MSE 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Referenzdaten
KW - Digitalisierung
KW - Data schema
KW - NFDI-MatWerk
KW - Datenschema
KW - FAIR
PY - 2024
AN - OPUS4-61175
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Jürgens, Maria
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Creep-fatigue of P92 in service-like tests with combined stress- and strain-controlled dwell times
N2 - Complex service-like relaxation- and creep-fatigue tests with strain- and stress-controlled dwells and fatigue cycle durations of approx. 2200 s were performed exemplarily on a grade P92 steel at 620 ◦C in this study. The results indicate deviations in the prevailing creep mechanisms of long-term relaxation and creep dwells, affecting subsequent dwells, load shifts, and the macroscopic softening behavior quite differently. In addition, fracture surfaces and longitudinal metallographic sections reveal intergranular crack growth for complex loading with stress-controlled dwells, whereas complex strain-controlled tests enhance oxidation and transgranular crack propagation. These findings substantiate the limited transferability of relaxation-fatigue to creep-fatigue conditions.
KW - Tempered martensite-ferritic steel
KW - P92
KW - Dwell periods
KW - Creep-fatigue interaction
KW - Stress relaxation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564239
DO - https://doi.org/10.1016/j.ijfatigue.2022.107381
SN - 0142-1123
VL - 168
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-56423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaudhuri, Somsubhro
A1 - Purayil, Sruthi Krishna Kunji
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Nielsen, Sören
T1 - Thermography-Assisted Mechanical Testing of Cold-Spray (AM) Repair
N2 - Cold Spray Additive Manufacturing (CSAM) is a solid-state process that is being increasingly used for structural repairs in aerospace and energy sectors. It enables the deposition of dense material at low temperatures by accelerating metal particles to supersonic velocities, thereby reducing thermal distortion. However, the structural integrity of CSAM repairs—particularly at the interface between the deposited layer and the substrate—remains a critical concern. Various post-treatments and characterization methods have been explored to optimize performance. While X-ray Computed Tomography (XCT) is effective for sub-surface inspection, it cannot be applied in situ during mechanical testing. Digital Image Correlation (DIC), a surface-based method, also lacks sub-surface sensitivity. To address this, Infrared Thermography (IRT) was employed alongside DIC during the tensile and fatigue testing of aluminum CSAM-repaired specimens. A cooled IRT camera operating at 200 FPS captured thermal data, with lock-in processing subsequently applied in post-processing. IRT successfully detected early interfacial damage and enabled the tracking of crack propagation, which was later confirmed through fracture surface analysis. This extended abstract presents findings from fatigue tests using IRT.
T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025)
CY - Kobe, Japan
DA - 15.09.2025
KW - Thermography
KW - Thermografie
KW - Thermal stress analysis
KW - Cold spray
KW - Damage detection
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642299
DO - https://doi.org/10.3390/proceedings2025129018
VL - 129
IS - 1
SP - 1
EP - 5
PB - MDPI
CY - Basel
AN - OPUS4-64229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
T1 - Aspekte der analytischen bruchmechanischen Bauteilbewertung
N2 - Am Beispiel eines abgesetzten zylindrischen Bauteils (Achsschenkel) werden Probleme der analytischen bruchmechanischen Bauteilbewertung diskutiert. Als Basis-philosophie wird ein Fail Safe-Kriterium (kontrolliertes Versagen) angesetzt. Die Forderung ist, dass sich der Achsschenkel, bevor er bricht, in einem Ausmaß plastisch verformen kann, bei dem der Fahrer bemerkt, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Um das zu gewährleisten, muss der Werkstoff einen bestimmten Riss-widerstand aufweisen. Dazu werden im hier vorgestellten ersten Teil des Projektes mittels FEM Rissspitzenbeanspruchungen in Abhängigkeit von der Auslenkung des Zylinders und angenommener Rissgrößen ermittelt. Diese finden als Zielgrößen in der weiteren Analyse Anwendung. Da eine einfach umzusetzende Lösung angestrebt wird, werden zusätzlich analytische Rechnungen an Ersatzgeometrien (halbunendliche Platte und Vollzylinder), aber mit den realen Spannungen am Bauteil durchgeführt. Es zeigt sich, dass die Ergebnisse wegen des Steifigkeitsunterschieds zwischen Bauteil und Ersatzgeometrie unvertretbar konservativ sind. Alternativ wird ein hybrides Konzept vorgestellt, für das die Modellparameter mittels FEM bestimmt werden. Es liefert sehr genaue Ergebnisse. Im Rahmen der analytischen Rechenvorschrift können die Lösungen auf andere Werkstoffe übertragen werden, ohne dass zusätzliche FEM-Analysen notwendig sind.
T2 - 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 22.02.2022
KW - Bauteilbewertung
KW - Fail-safe
KW - Analytisches Modell
KW - FEM
PY - 2022
AN - OPUS4-54408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ávila Calderón, Luis Alexander
A1 - Matzak, Kathrin
A1 - Olbricht, Jürgen
A1 - Dolabella Portella, Pedro
A1 - Skrotzki, Birgit
T1 - BAM Reference Data: High Temperature Tensile Data of Single-Crystal Ni-Based Superalloy CMSX-6
N2 - This publication provides comprehensive metadata and test results of tensile tests at elevated temperature according to DIN EN ISO 6892-2:2018-09 on the single crystal Ni-based superalloy CMSX-6 at T = 980 °C. The tests were performed in an ISO 17025-accredited test laboratory. The calibrations of measuring equipment are documented, meet the requirements of the measurement standard, and are metrologically traceable. The provided data were audited and are BAM reference data.
KW - Digitalisierung
KW - Referenzdaten
KW - CMSX-6
KW - Zugversuch
KW - NFDI-MatWerk
KW - Ni-Basis-Superlegierung
PY - 2025
DO - https://doi.org/10.5281/zenodo.17846616
PB - Zenodo
CY - Geneva
AN - OPUS4-65338
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Determination of critical local straining conditions for solidification cracking at laser beam welding by experimental and numerical methods
N2 - The phenomenon of solidification cracking has been the subject of numerous research projects over the years. Great efforts have been made to understand the fundamentals of hot cracking. It is generally agreed that solidification cracks form in the solidification range between the liquidus and solidus temperatures under the combination of thermal, metallurgical and mechanical factors. There is still a need to determine the time-resolved strain distribution in the cracksensitive region in order to analyse the local critical conditions for solidification cracking phenomena. This was a strong motivation for the development of a measurement system used in this study to estimate the local strains and strain rates in the zone where the solidification crack is expected to occur. The laser beam welding experiments were conducted using the Controlled-Tensile-Weldability test (CTW test) to apply an external strain condition during welding to generate solidification cracks. The CTW test is a test method for investigating the suscep�tibility of laser-welded joints to solidification cracking, in which the sample can be subjected to a defined strain at a defined strain rate during welding. In combination with experimental investigations, numerical simulations provide spatially detailed and time-dependent information about the strain development during the welding process, especially regarding the critical conditions for solidification cracking. Therefore, this tool was also used in the present study to evaluate the accuracy of measurement methods and to estimate experimentally derived values and their concrete influence on the formation of solidification cracks. By integrating experimental methods and numerical simulations, this study investigates the spatially resolved and temporally changing development of strain during welding, with a particular focus on the critical conditions that lead to the formation of solidification cracks.
T2 - GAMM 94th Annual Meeting
CY - Magdeburg, Germany
DA - 18.03.2024
KW - Laser beam welding
KW - Solidification cracking
KW - FEM simulation
PY - 2024
AN - OPUS4-62417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Topolniak, Ievgeniia
T1 - Direct laser writing of mussel inspired polydopamine
N2 - Polydopamine (PDA) is one of the simplest and most versatile approaches for forming an excellent binding exterior to confer new functionalities to nearly any material surface. Inspired by nature, it mimics the behavior of mussels and can be easily deposited on virtually all types of inorganic and organic substrates, including superhydrophobic surfaces. Moreover, PDA exhibits high potential for surface modification and diversified secondary reactions that makes it extremely interesting for a wide range of application including biomedical field, e.g., drug delivery, adhesives, cell adhesion, biosensing. PDA has undergone significant expansion in its applications and is one of the most attractive areas within the materials field. Nevertheless, PDA integration in microdevices is still constrained by poor spatial and temporal control of excited deposition methods.
Herein, we demonstrate a novel maskless approach for PDA micropatterning based on Direct Laser Writing that overcomes present limitations. The pattern is formed upon exposure of the dopamine solution by light produced by tightly-focused fs NIR laser that scans substrate surface accordingly to the selected pattern design. Neither strong oxidants, metal ions nor adjusting pH to alkaline is required by this technique to perform dopamine polymerization. Our method achieves the PDA micropatterns with the spatial resolution of 0.8 µm, at least an order of magnitude smaller than what is possible with other PDA microplanning techniques. Some examples of PDA patterns are shown in Figure 1. The here introduced PDA deposition technique will uniquely unravel applications of polydopamine and other catecholamine-based mussel-inspired materials in various multifunctional systems and microdevices (e.g., MEMS elements, microfluidics).
The chemical nature of PDA was confirmed by locally recorded vibrational and x-ray photoelectron spectra. Moreover, the morphology and thickness of PDA microstructure can be controlled by the laser power and scanning velocity revealing the possibility of fabricating the structures with gradient. In most of the applied conditions the increase of the laser intensity and decrease of the scanning velocity would lead to the thicker PDA pattern. Different morphologies from smooth and bulky-like to grain like has been obtained.
PDA was produced in the presence of tris buffer, phosphate buffer and DI water only. We also tested the effect of the solution pH applying pH 6.0, 7.0 and 8.5. Furthermore, the effect of antioxidants and purging of the solution with oxygen and nitrogen was investigated. Summarizing, we could see that the structures could be produced in all the given conditions, however their thickness and quality, morphology and roughness would differ. We did not observe negative impact of the antioxidants and nitrogen purging on the performance of PDA build up indicating that the PDA formation mechanism is different to common autooxidation. The current mechanism is based on the interaction of dopamine molecules with the photoinitiator added to solution as active to DLW laser light component.
Apart from the glass substrate, we achieved PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips.
We also performed facile posts-modification of the PDA surface with protein enzymes like trypsin that was confirmed by XPS. Obtained bioactive pattern could be further integrated in the protein sensing devices.
Presented in this work DLW-based microfabrication technique and the possibilities for further PDA surface post-functionalization empowers advanced applications of this material in single-molecule bioassays, sensors and other complex microdevices.
T2 - MNE EUROSENSORS
CY - Leuven, Belgium
DA - 19.09.2022
KW - Polydopamine
KW - Two-photon polymerisation
KW - Micropatterning
PY - 2022
AN - OPUS4-56421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Baer, Wolfram
A1 - Wagener, Rainer
A1 - Kiyak, Yusuf
T1 - Betriebsfestigkeit und Bruchverhalten von bainitischen Schmiedestählen
N2 - Die neue Generation von bainitischen Schmiedestählen bietet auf der einen Seite ein erhebliches Festigkeitspotenzial, das es im Sinne des Leichtbaus auch für zyklisch belastete Sicherheitsbauteile zu heben gilt. Auf der anderen Seite geht mit dieser Festigkeitssteigerung im Vergleich zu Vergütungsstählen ein Verlust an Duktilität und Zähigkeit einher. Am Beispiel des Demonstratorbauteils Achsschenkel ging das Forschungsvorhaben der Frage nach, wie ein Freigabeprozess zu gestalten ist, damit das Festigkeitspotenzial der neuen Stähle zuverlässig ausgenutzt werden kann. Als Ergebnis wird eine Vorgehensweise dargestellt, die den Eigenschaften der neuen Generation von Schmiedestählen Rechnung trägt, um den sicheren Betrieb der Komponenten zu gewährleisten.
KW - Bainitischer Schmiedestahl
KW - Bruchmechanik
KW - Sicherheit
KW - Betriebsfestigkeit
KW - Bauteilauslegung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594296
SN - 2366-5106
SP - 50
EP - 54
PB - Industrieverband Massivumformung e. V
CY - Hagen
AN - OPUS4-59429
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Madia, Mauro
A1 - Schröpfer, Dirk
A1 - Kruse, Julius
A1 - Saliwan Neumann, Romeo
A1 - Kannengießer, Thomas
T1 - Influence of Ultrasonic-Assisted Milling on Surface Integrity and Fatigue Strength of a Low Alloy Steel
N2 - The milling process significantly influences the surface integrity of metallic components through machining induced near surface residual stresses. Modern hybrid machining processes, such as ultrasonic-assisted milling (USAM), offer the potential to induce beneficial near-surface compressive residual stresses compared to the near-surface tensile residual stresses typically resulting from conventional milling (CM). This study investigates the effects of USAM compared to CM on the near-surface residual stress state and fatigue performance of a S355J2C low-alloy steel. Milling experiments and subsequent rotating bending tests revealed that USAM significantly reduces cutting force by approximately 45% and induces near-surface compressive re sidual stresses as low as −733MPa. This leads to a significant improvement in fatigue strength estimated in approximately 34% compared to polished specimens and 11% compared to the CM. These findings highlight the potential of USAM to enhance the fatigue performance of components made of steel.
KW - Fatigue strength
KW - Residual stress
KW - Surface integrity
KW - Surface roughness
KW - Ultrasonic-assisted milling
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657358
DO - https://doi.org/10.1111/ffe.70259
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-65735
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Jonathan
T1 - Near-real-time in-situ powder bed anomaly detection using machine learning algorithms for high-resolution image analysis in PBF-LB/M
N2 - In-situ captured visual images of the laser powder bed fusion process (PBF-LB/M) provide valuable insights into process dynamics. Automatic analysis of after-recoating images using machine learning algorithms enables the detection of process deviations to reduce scrap production. However, current industrial monitoring systems for PBF-LB/M are limited by low image resolution. While higher resolutions enable the system’s ability to capture smaller features, they increase storage and computational demand.
Edge devices offer a solution by enabling near-real-time, on-premises image analysis within the machine and company network. In this study, high-resolution after-recoating images, captured with a spatial resolution of 17 µm/pixel and an image size of 9344 x 7000 pixels, were processed on an Nvidia Jetson Orin NX16 edge device. The images were downscaled, and anomaly detection algorithms were used to identify regions of interest for segmentation and classification at full resolution. To address computational constraints, state-of-the-art anomaly detection algorithms were evaluated and an appropriate downscaling factor for the on-edge implementation was determined. The EfficientAD algorithm achieved promising results, detecting anomalies within an inference time of less than 10 seconds. The presented framework enables anomaly detection with a maximum delay of one layer. This lays the foundation for the future development of near-real-time intervention in the PBF-LB/M process.
T2 - ISAM 2025 – 6th International Symposium on Additive Manufacturing
CY - Dresden, Germany
DA - 21.05.2025
KW - Additive manufacturing
KW - Image processing
KW - In-situ monitoring
KW - Powder bed fusion
PY - 2025
AN - OPUS4-63231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Tensile stress relaxation test ontology (TSRTO)
N2 - Tensile Stress Relaxation Test Ontology (TSRTO) has developed for representing the tensile stress relaxation testing process, testing equipment requirements, test pieces charactristics, and related testing parameters and their measurement procedure according to DIN EN ISO 10319-1 standard.
Versions info:
V1 developed using BFO+CCO top-level ontologies.
V3 developed using PROV+PMDco top-level ontologies.
Repositories:
GitLab: https://gitlab.com/kupferdigital/process-graphs/relaxation-test
GitHub: https://github.com/HosseinBeygiNasrabadi/Tensile-Stress-Relaxation-Test-Ontology-TSRTO
MatPortal: https://matportal.org/ontologies/TSRTO
IndustryPortal: https://industryportal.enit.fr/ontologies/TSRTO
KW - Ontology
KW - Tensile stress relaxation testing
KW - FAIR data
PY - 2024
UR - https://gitlab.com/kupferdigital/process-graphs/relaxation-test
UR - https://github.com/HosseinBeygiNasrabadi/Tensile-Stress-Relaxation-Test-Ontology-TSRTO
UR - https://matportal.org/ontologies/TSRTO
UR - https://industryportal.enit.fr/ontologies/TSRTO
PB - GitLab
CY - San Francisco, CA, USA
AN - OPUS4-60546
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tahir, Warisha
A1 - Liberra, Eric
A1 - Khalil, Islam E.
A1 - Das, Prasenjit
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Schmidt, Johannes
A1 - Bergmann, Arno
A1 - Cuenya, Beatriz Roldan
A1 - Thomas, Arne
T1 - Cu2O@COF core–shell catalyst for electrochemical CO2 reduction
N2 - The electrochemical reduction of CO2 (CO2RR) to C2+ products offers a sustainable approach for carbon utilization and the production of valuable chemicals. Cu2O nanocubes (NCs) have emerged as effective electrocatalysts for the formation of C2+ products. In this study, we applied a coating of Cu2O NCs with robust covalent organic framework (COF) layers prepared by multicomponent reactions. Compact layers of COFs are formed, which, due to their porosity, allow full accessibility of the Cu2O catalytic surfaces to CO2 molecules. Furthermore, the thickness and chemical functionality of the COF layers can be continuously varied by changing the type and quantity of monomers used to cover the Cu2O NCs. Electrocatalytic measurements demonstrate that these hybrid core–shell Cu@COF systems remain active in CO2 reduction, achieving good current density and faradaic efficiency, while maintaining selectivity for the desired CO2 reduction products. Additionally, the COF shell provides remarkable stability to the system under electrochemical conditions.
KW - Electrochemical CO2 reduction
KW - Copper(I) oxide
KW - Nanocubes
KW - COF
KW - Core shell
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659177
DO - https://doi.org/10.1039/d5ta09283c
SN - 2050-7488
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
CY - London [u.a.]
AN - OPUS4-65917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulmer, A.
T1 - Making Every Particle Count: The ConcenSus Approach to Nanoparticle Metrology
N2 - Engineered nanoparticles offer immense potential across diverse applications, from drug delivery and catalysis to quantum dot lasers and solar cells. At the same time, persistent and emerging nanoscale pollutants are becoming increasingly significant. Despite this growing relevance, validated and standardized methods for measuring nanoparticle number concentrations remain scarce, hindering regulatory compliance and technological innovation.
The ConcenSus project, a collaborative effort by a European metrology consortium, aims to address this gap through a comprehensive, multi-faceted approach. Three representative test materials will be developed, guided by the specific needs of key industrial sectors identified through a stakeholder survey. The performance of state-of-the-art number concentration measurement methods—both particle counting and ensemble-based techniques—will be systematically evaluated.
Among these, Small-Angle X-ray Scattering (SAXS) is a cornerstone technique, delivering unparalleled, statistically robust, traceable structural parameters and standing out as one of the most promising methods for determining number concentrations of soft-matter systems. However, SAXS can only deliver fully validated number concentrations when accurate input quantities—particularly particle density—are known. Similarly, optical ensemble-based methods depend on precise knowledge of the refractive index (RI). Therefore, one of the major challenges addressed in this project is the traceable determination of nanoparticle density and RI to establish reliable, low-uncertainty standards for total particle number concentration measurements.
To ensure broad applicability—including health and personal care, energy and semiconductor industries, and environmental monitoring—a wide range of nanoparticle samples will be investigated using SAXS as a primary ensemble technique, complemented by other ensemble methods and direct particle counting. Standardized sample preparation protocols will be developed, and an interlaboratory comparison will validate the measurement approaches. This poster presents the project roadmap toward new standard materials and documentary standards for traceable nanoparticle number concentration measurements.
T2 - 22nd Nordic Workshop on Scattering from Soft Matter (NSSM)
CY - Lund, Sweden
DA - 13.01.2026
KW - Particles
KW - Concentration
KW - Metrology
KW - Particle density
KW - Refractive index
PY - 2026
UR - https://kemisamfundet.se/event/22nd-nordic-workshop-on-scattering-from-soft-matter/
AN - OPUS4-65928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulmer, A.
T1 - Making Every Particle Count: The ConcenSus Approach to Nanoparticle Metrology
N2 - Engineered nanoparticles offer immense potential across diverse applications, from drug delivery and catalysis to quantum dot lasers and solar cells. At the same time, persistent and emerging nanoscale pollutants are becoming increasingly significant. Despite this growing relevance, validated and standardized methods for measuring nanoparticle number concentrations remain scarce, hindering regulatory compliance and technological innovation.
The ConcenSus project, a collaborative effort by a European metrology consortium, aims to address this gap through a comprehensive, multi-faceted approach. Three representative test materials will be developed, guided by the specific needs of key industrial sectors. The performance of state-of-the-art number concentration measurement methods—both particle counting and ensemble-based techniques—will be systematically evaluated.
Among these, Small-Angle X-ray Scattering (SAXS) is a cornerstone technique, delivering unparalleled, statistically robust, traceable structural parameters and standing out as one of the most promising methods for determining number concentrations of soft-matter systems. However, SAXS can only deliver fully validated number concentrations when accurate input quantities—particularly particle density—are known. Similarly, optical ensemble-based methods depend on precise knowledge of the refractive index (RI). Therefore, one of the major challenges addressed in this project is the traceable determination of nanoparticle density and RI to establish reliable, low-uncertainty standards for total particle number concentration measurements.
To ensure broad applicability—including health and personal care, energy and semiconductor industries, and environmental monitoring—a wide range of nanoparticle samples will be investigated using SAXS as a primary ensemble technique, complemented by other ensemble methods and direct particle counting. Standardized sample preparation protocols will be developed, and interlaboratory comparisons will validate the measurement approaches. This poster presents the project roadmap towards new standard materials and documentary standards for traceable nanoparticle number concentration measurements.
T2 - SAXS excites & XRD excites 2026
CY - Graz, Austria
DA - 13.04.2026
KW - Particles
KW - Concentration
KW - Metrology
KW - Particle density
KW - Refractive index
PY - 2026
UR - https://www.anton-paar.com/corp-en/saxs-xrd-excites/?srsltid=AfmBOoqqdYhwDL6_ywhpBpHT30_kC8YHKgEB3RJJ3zK-47pqWYBuGP-M
AN - OPUS4-65929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cameli Manzo, Riccardo
A1 - Baran, Volodymyr
A1 - Shevchenko, Artem
A1 - Sleptsova, Anastasia
A1 - Hoffmann, Frank
A1 - Stolar, Tomislav
A1 - Dinnebier, Robert E.
A1 - Etter, Martin
T1 - N-Methylated Nucleobases Crystal Structures and π-π Stacking Interactions
N2 - Solid-state studies evaluating intermolecular geometries in methylated nucleobases are not extensively explored. In the course of the present study, we have solved the crystal structures of 1-, 3- and 7-methylated adenines and guanines, including the monohydrate and sesquihydrate forms of 3-methyladenine and 3-methylguanine, respectively, by means of single-crystal X-ray diffraction and synchrotron/laboratory X-ray powder diffraction (XRPD). In situ high temperature XRPD experiments, coupled with differential thermal analysis/thermogravimetry (DTA/TG) measurements, allowed for monitoring crystallographic changes after water removal of N3-methylated compounds, and the discovery of a high temperature polymorph in the case of 3-methyladenine. Our findings indicate that H-bonding schemes describe ribbon planar motifs of molecules in the majority of cases, or linear double-bonded strands of molecules in a few cases. π-π stacking interactions were compared with existing findings of theoretical calculations and existing crystallographic data, showing how N-methylated purine bases follow the trend predicted by Hunter and Sanders, 1990. The present study provides the first systematic experimental insights into the solid state of the presented compounds.
KW - Solid state
KW - Synchrotron PXRD
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659188
DO - https://doi.org/10.3390/molecules31081326
VL - 31
IS - 8
SP - 1
EP - 30
PB - MDPI
CY - Basel
AN - OPUS4-65918
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huo, Wenjie
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, Katinka
T1 - Detection of solidification crack formation in laser beam welding videos of sheet metal using neural networks
N2 - AbstractLaser beam welding has become widely applied in many industrial fields in recent years. Solidification cracks remain one of the most common welding faults that can prevent a safe welded joint. In civil engineering, convolutional neural networks (CNNs) have been successfully used to detect cracks in roads and buildings by analysing images of the constructed objects. These cracks are found in static objects, whereas the generation of a welding crack is a dynamic process. Detecting the formation of cracks as early as possible is greatly important to ensure high welding quality. In this study, two end-to-end models based on long short-term memory and three-dimensional convolutional networks (3D-CNN) are proposed for automatic crack formation detection. To achieve maximum accuracy with minimal computational complexity, we progressively modify the model to find the optimal structure. The controlled tensile weldability test is conducted to generate long videos used for training and testing. The performance of the proposed models is compared with the classical neural network ResNet-18, which has been proven to be a good transfer learning model for crack detection. The results show that our models can detect the start time of crack formation earlier, while ResNet-18 only detects cracks during the propagation stage.
KW - Artificial Intelligence
KW - Software
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586116
DO - https://doi.org/10.1007/s00521-023-09004-y
SN - 0941-0643
VL - 35
IS - 34
SP - 24315
EP - 24332
PB - Springer Science and Business Media LLC
AN - OPUS4-58611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thünemann, Andreas
T1 - Back to the roots: Line-focus convoluted models in small-angle X-ray scattering
N2 - We present analytically convoluted expressions for models commonly used in small-angle X-ray scatteringv(SAXS), specifically for measurements made with instruments operating in line-focus (Kratky-type) or Ultra-SAXS (Bonse-Hart) geometries. Starting with Guinier's approximation for determining the radii of gyration, we discuss power laws, random-coil conformations of macromolecules, and spherical nanoparticles. We provide expressions for the Guinier-Porod model, the Teubner-Strey model (for microemulsions), and the generalized Ornstein-Zernike model (for gels and nanogels1). An example of the Teubner-Strey model is provided. The line-convoluted models discussed here are intended for interpreting data that has not been deconvoluted (i.e., not "desmeared"). Using line-convoluted data allows for lower detection limits and shorter measurement times compared to deconvoluted data, as artifacts introduced by deconvolution can be avoided by applying these models. We suggest utilizing line-convoluted models for high-throughput in-house SAXS analysis, which could enable time-saving routine examinations. For instance, SAXS investigations could help determine whether certain materials should be classified as nanomaterials under the European Commission's regulatory.
T2 - SAXS and XRD excites
CY - Graz, Austria
DA - 13.04.2026
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticles
KW - Advanced materials
KW - Reference materials
KW - Reference product
KW - Reference method
PY - 2026
AN - OPUS4-65897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Topolniak, Ievgeniia
T1 - Direct laser surface micropatterning with polydopamine
N2 - Inspired by the chemistry of mussel adhesive proteins, polydopamine (PDA) is one of the simplest and most versatile approaches to confer new functionalities to nearly any material surface. Moreover, PDA exhibits high potential for surface modification and diversified secondary reactions that makes it extremely interesting for a wide range of application including biomedical field, e.g., drug delivery, adhesives, cell adhesion, biosensing. PDA has undergone significant expansion in its applications and is one of the most attractive areas within the materials field. Nevertheless, PDA integration in microdevices is still constrained by poor spatial and temporal control of excited deposition methods.
Herein, we demonstrate a novel maskless approach for PDA micropatterning based on Direct Laser Writing (DLW) that overcomes present limitations. The pattern is formed upon exposure of the dopamine solution by light produced by tightly-focused fs NIR laser that scans substrate surface accordingly to the selected pattern design. Neither strong oxidants, metal ions nor adjusting pH to alkaline is required by this technique. Our method achieves the PDA micropatterns with the spatial resolution of 0.8 µm, at least an order of magnitude smaller than what is possible with other PDA microplanning techniques. The here introduced PDA deposition technique will uniquely unravel applications of polydopamine and other catecholamine-based mussel-inspired materials in various multifunctional systems and microdevices (e.g., MEMS elements, microfluidics).
Adjustment of MPL parameters revealed that the morphology and thickness of resulted PDA microstructures can be controlled by altering the laser power and its scanning velocity. As a result, it also enables the production of micropatterns with structural gradient.
Apart from the glass substrate, we achieved PDA patterning at surfaces of different nature such as polychlorotrifluoroethylene, polydimethylsiloxane, polyethylene terephthalate, silicon wafers, and fluorinated glass coverslips.
The chemical nature of PDA was confirmed by locally recorded vibrational and x-ray photoelectron spectra. To ensure post-modification potential of MPL deposited PDA we demonstrated one-step deposition of micropatterns with trypsin. Obtained bio-functionalised surface can be further applied as a protein sensing active microelement.
Presented in this work DLW-based microfabrication technique and the possibilities for further PDA surface post-functionalization empowers advanced applications of this material in single-molecule bioassays, sensors and other complex microdevices.
T2 - Swiss ePrint 2022
CY - Buchs, Switzerland
DA - 05.09.2022
KW - Polydopamine
KW - Two-photon polymerisation
KW - Micropatterning
PY - 2022
AN - OPUS4-56422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Rethmeier, Michael
A1 - Biegler, M.
A1 - Javaheri, E.
T1 - Qualifizierung der instrumentierten Eindringprüfung zur Kennwertermittlung für hochfeste Stähle mit Schweißungen
N2 - Der Einsatz von hochfesten Stählen im Karosseriebereich des Automobilbaus hat während der letzten Jahre stark zugenommen. Hierzu zählen Dual- und Komplexphasenstähle, welche durch Kombination unterschiedlicher Gefügebestandteile auch deren Vorteile kombinieren, sowie TRIP (TRansformation Induced Plasticity) und Mangan-Bor Stähle, welche sehr gute Umformeigenschaften mit hohen Festigkeiten durch Martensitbildung bei der Umformung kombinieren. TWIP (Twinning Induced Plasticity) Stähle erreichen ähnliche Effekte durch forcierte Zwillingsbildung.
Die Ursachen für den Einsatz dieser Stähle liegen in dem Potential dieser Materialien zur Gewichts- und Kostenreduzierung, bei gleichzeitiger Erhöhung der Fahrgastsicherheit. Auf Grund der prinzipiell gegebenen Schweißeignung dieser Stähle, werden die klassischen Fügeverfahren im Karosseriebau wie das kostengünstige und effektive Widerstandspunktschweißen, das Metall-Schutzgas (MSG)-Schweißen oder das Laserschweißen angewendet. Allerdings treten teilweise Herausforderungen, beispielsweise durch Gefügeveränderungen in den Fügestellen auf, die zu ungewollten Aufhärtungen oder Erweichungen führen.
In diesem Projekt wird ein Verfahren entwickelt, mit welchem die lokalen Werkstoffeigenschaften von im Automobilbau typischen Werkstoffen und deren Fügestellen bestimmt werden können. Relevante Kennwerte sind in erster Linie das SpannungsDehnungs-Verhalten der verschiedenen Zonen einer Schweißverbindung; relevante Zonen wiederum sind neben dem Grundwerkstoff die Wärmeeinflusszone und das Schweißgut. Zu diesem Zweck wird das Verfahren der instrumentierten Eindringprüfung für den Einsatz bei hochfesten Stählen weiterentwickelt. Zunächst werden hierzu Zugversuche an einfachen Grundwerkstoffgeometrien durchgeführt. Im Anschluss wird die optische Dehnungsfeldmessung an stark taillierten, geschweißten Zugversuchsproben durchgeführt.
Die Taillierung dient dem Zweck, die WEZ auch mittels WPS über den gesamten Querschnitt der Probe erzeugen zu können, bzw. im Versuch auch Dehnungen in den relevanten Bereichen herbeizuführen.
Das im Projekt angewendete Auswerteverfahren, welches auf nichtlinearen Regressionsmodellen in Form von künstlichen, neuronalen Netzwerken beruht, ermöglicht die Vorhersage des Festigkeitsverhaltens des Werkstoffes anhand der gemessenen Krafteindringwegdaten.
KW - Eindringprüfung
KW - Hochfester Stahl
KW - Prüfverfahren
PY - 2020
SN - 978-3-946885-98-6
SP - 1
EP - 164
PB - Forschungsvereinigung Stahlanwendungen
AN - OPUS4-57322
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Javaheri, E.
A1 - Kumala, V.
A1 - Javaheri, A.
A1 - Rawassizadeh, R.
A1 - Lubritz, J.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Quantifying Mechanical Properties of Automotive Steels with Deep Learing Based Computer Vision Algorithms
N2 - This paper demonstrates that the instrumented indentation test (IIT), together with a trained artificial neural network (ANN), has the capability to characterize the mechanical properties of the local parts of a welded steel structure such as a weld nugget or heat affected zone.
Aside from force-indentation depth curves generated from the IIT, the profile of the indented surface deformed after the indentation test also has a strong correlation with the materials’ plastic behavior. The profile of the indented surface was used as the training dataset to design an ANN to determine the material parameters of the welded zones. The deformation of the indented surface in three dimensions shown in images were analyzed with the computer vision algorithms and the obtained data were employed to train the ANN for the characterization of the mechanical properties. Moreover, this method was applied to the images taken with a simple light microscope from the surface of a specimen. Therefore, it is possible to quantify the mechanical properties of the automotive steels with the four independent methods: (1) force-indentation depth curve; (2) profile of the indented surface; (3) analyzing of the 3D-measurement image; and (4) evaluation of the images taken by a simple light microscope. The results show that there is a very good Agreement between the material parameters obtained from the trained ANN and the experimental uniaxial tensile test. The results present that the mechanical properties of an unknown steel can be determined by only analyzing the images taken from its surface after pushing a simple indenter into its surface.
KW - Deep learning
KW - Computer vision
KW - Artificial neural network
KW - Clustering
KW - Mechanical properties
KW - High strength steels
KW - Instumented indentation test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503038
DO - https://doi.org/10.3390/met10020163
VL - 10
IS - 2
SP - 163
PB - MDPI
AN - OPUS4-50303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Nahteigenschaftsverbesserung von dickwandigen laserstrahlgeschweißten Duplexblechen mittels pulveraufgetragenen Pufferschichten
N2 - Duplexstähle finden aufgrund ihrer Eigenschaften, wie der guten Korrosionsbeständigkeit, einer hohen Festigkeit bei gleichzeitig guter Duktilität häufig industrielle Anwendung. Durch die hohen Abkühlraten beim Laserstrahlschweißen weisen Schweißnähte jedoch anstelle eines ausgeglichenen Duplexgefüges einen deutlich erhöhten Ferritanteil, im Vergleich zum Basiswerkstoff, auf. Dies führt zu einer verringerten Duktilität sowie Korrosionsbeständigkeit. Um dieses Problem zu lösen, wurde ein Prozess entwickelt, der auf einer Kantenbeschichtung mit nickelhaltigem Zusatzmaterial der zu fügenden Bleche mittels Laser-Pulver-Auftragschweißen (LPA) basiert.
Die resultierenden Schweißnähte wurden zerstörend anhand von Schliffbildern, EDX-Aufnahmen, Härtemessungen und Kerbschlagbiegeversuchen geprüft.
T2 - 40. Assistentenseminar der Füge- und Schweißtechnik
CY - Braunlage, Germany
DA - 25.09.2019
KW - Laser-Pulver-Auftragschweißen; Laserstrahlschweißen, Duplex, Pufferschichten
PY - 2020
VL - 357
SP - 131
EP - 140
PB - DVS Media
CY - Düsseldorf
AN - OPUS4-50144
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Influence of heat input on cooling rates and mechanical properties of laser hybrid welded thick structural steels
N2 - The laser hybrid welding process offers many advantages such as the high penetration depth and high welding speed, and it is characterized by its low heat input compared to the arc-based welding processes, which makes the laser hybrid welding process as a suitable alternative process when welding thick-walled steels. However, there are some challenges when using laser hybrid welding process for thick steels. Due to the uneven cooling conditions and the inhomogeneous filler wire mixing, a typical laser hybrid weld can be divided into two different zones over the depth: the arc-dominated zone on the upper part and the laser-dominated zone in the root part. This leads to different mechanical properties in a laser hybrid welded joint. Due to the high cooling rates and the lack of filler wire in the laser-dominated zone, this area is more critical regarding the mechanical properties, especially the Charpy impact toughness. A low heat input can lead to undesired microstructure consisting of martensite, hardening and deteriorated impact toughness due to the high cooling rate, where higher heat inputs can lead to grain-coarsening and even loss of impact strength. This study deals with the influence of the welding speed and resulting heat input on the cooling rates, the microstructure and the mechanical properties of single-pass laser hybrid welded steels of S355J2 with thickness up to 30 mm. The experiments were performed with a 20-kW fibre laser system and a contactless electromagnetic weld backing on up to 30 mm thick steels in butt-joint configuration in 1G welding position. The cooling time was measured in three different locations near to fusion lines corresponding to different heights of the seam using a special configuration with pyrometers, collimators, and optical fibres. The test specimens for the Charpy impact testing and tensile testing were extracted in up to three different depths. Based on the experiments, a heat input of 1.3 kJ/mm - 1.6 kJ/mm, 2 kJ/mm - 2.4 kJ/mm and 3.7 kJ/mm were recommended when single-pass laser hybrid welding of 20 mm, 25 mm and 30 mm thick structural steels in regard to the minimum requirements of the mechanical properties, respectively. The optical measurement of the cooling times in different depths could be carried out reproducibly.
T2 - Advances in Welding and Metal Additive Manufacturing Technologies 2023
CY - Istanbul, Türkiye
DA - 30.10.2023
KW - Laser hybrid welding
KW - Electromagnetic backing
KW - Charpy impact toughness
KW - Thick-plate welding
KW - Thermal cycles
PY - 2023
AN - OPUS4-58942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Yin, Huajie
A1 - Smales, Glen Jacob
A1 - Harrison, W. J.
A1 - Budd, P. M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Polymers of intrinsic microporosity - Molecular mobility and physical aging revisited by dielectric spectroscopy and X‑ray scattering
N2 - Polymers of intrinsic microporosity (PIMs) are promising candidates for the active layer in gas separation membranes due to their high permeability and reasonable permselectivity. These appealing properties originate from a microporous structure as a result of inefficient segment packing in the condensed state due to a combination of a ladder-like rigid backbone and sites of contortion. However, this class of polymers suffers from a significant decrease in the permeability with time due to physical aging, whereby typically, the permselectivity increases. The initial microporous structures approach a denser state via local rearrangements, leading to the reduction of the permeability. Hence, a detailed characterization of the molecular mobility in such materials can provide valuable information on physical aging. In this work, the dielectric behavior of PIM-1 films and their behavior upon heating (aging) were revisited by isothermal frequency scans during different heating/cooling cycles over a broad temperature range between 133 and 523 K (−140 to 250 °C). In addition, the obtained results were compared with data of samples that were annealed at ambient temperatures over different time scales. Multiple dielectric processes were observed: several relaxation processes due to local fluctuations and a Maxwell−Wagner−Sillars polarization effect related to the microporosity. The temperature dependence of the rates of all processes follows the Arrhenius law where the estimated activation energy depends on the nature of the process. The influence of the thermal history (aging) on the processes is discussed in detail.
KW - Polymers of intrinsic microporosity
PY - 2022
DO - https://doi.org/10.1021/acs.macromol.2c00934
VL - 55
SP - 7340
EP - 7350
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-55485
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed Aejaz
A1 - Szymoniak, Paulina
A1 - Smales, Glen Jacob
A1 - Alentiev, D.
A1 - Bermeshev, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation
N2 - For the first time, dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbones and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter is related to the glassy dynamics of the flexible -Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain rich and backbone rich domains. This is confirmed through temperature modulated DSC measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using Fast Scanning Calorimetry employing both fast heating and cooling rates. This is complimented with scattering experiments that show how the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with -Si(OR)3 side groups, which is interpreted in terms of a percolation model.
KW - Polynorbornenes
KW - Broadband Dielectric Spectrscopy
KW - Advanced calorimetry
PY - 2020
DO - https://doi.org/10.1021/acs.macromol.0c01450
VL - 53
IS - 17
SP - 7410
EP - 7419
PB - ACS
AN - OPUS4-51196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Porosity prediction in laser beam welding with a multimodal physics-informed machine learning framework
N2 - Laser beam welding (LBW) of metallic components is a knowledge‑intensive manufacturing process whose quality depends on the complex multi‑physics. However, its engineering application is often hindered by the occurrence of porosity defects. Achieving a thorough understanding and reliable prediction of porosity defects remains difficult because it demands robust representation and reasoning over nonlinear and hard‑to‑observe physical information. In this study, we propose an integrated multimodal physics-informed machine learning (PIML) framework with the help of multi-physical modelling and experimental data to predict the porosity defects in laser beam welding of aluminum alloys. The whole framework contains a multimodal PIML model for predicting the porosity ratio and an ML-based estimator for relevant physical information. By utilizing the scalar welding parameters and high-dimensional physical information (probability of keyhole collapses, cumulative existing time of collapses, and molten pool geometry) as inputs, the multimodal PIML model shows great superiority in predicting the porosity ratio, with a reduction of the mean square error by 45%, compared with the ML model trained only with welding parameters. The ML-based estimator constructed with an encoder‐decoder architecture can accurately reproduce the critical physical information within a timeframe of seconds. By integrating these two ML models, the proposed framework advances engineering informatics by offering a scalable, physics-knowledge‑centric solution for fast and accurate porosity prediction in LBW manufacturing.
KW - Laser beam welding
KW - Porosity defect
KW - Physics-informed machine learning
KW - Multimodal model
KW - Simulation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657589
DO - https://doi.org/10.1016/j.aei.2026.104611
SN - 1474-0346
VL - 74
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-65758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Akyel, Fatma
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Brunner-Schwer, Christian
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of heat input on cooling rates and mechanical properties of laser hybrid welded thick structural steels
N2 - Laser hybrid welding presents several challenges when used to weld thick steels. A typical weld is divided into the arcdominated and laser-dominated zone. These zones lead to variations in the mechanical properties of the weld. The laserdominated zone is of particular importance regarding mechanical properties, notably Charpy impact toughness, due to the high cooling rates and the absence of filler wire. The low heat input of the laser can lead to martensitic microstructure causing hardening and deterioration of impact toughness. The high heat input of the arc can lead to grain coarsening and even loss of impact toughness. This study examines the influence of heat input on the cooling rates, microstructure and mechanical properties of single-pass laser hybrid welded steels of S355J2 and EH36 with thicknesses up to 30 mm. The experiments were performed with a 20-kW fibre laser and a contactless electromagnetic weld backing in the butt-joint configuration in 1G welding position. The cooling time was measured in three different locations near the fusion lines corresponding to different heights of the seam using a special configuration with pyrometers, collimators and optical fibres. The test specimens for the Charpy impact testing and tensile testing were extracted in three different depths. The experiments indicated that a heat input of 1.6 kJ/mm–2 kJ/mm, 2 kJ/mm–2.4 kJ/mm and 3.7 kJ/mm were recommended when single-pass laser hybrid welding of 20-, 25-, and 30-mm-thick structural steels regarding the minimum requirements of the mechanical properties, respectively.
KW - Laser hybrid welding
KW - Heat input
KW - Mechanical properties
KW - Charpy impact toughness
KW - Cooling rate
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625282
DO - https://doi.org/10.1007/s40194-025-01924-8
SN - 1878-6669
SP - 1
EP - 15
PB - Springer
CY - United Kingdom
AN - OPUS4-62528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simón Muzás, Juan
A1 - Brunner-Schwer, Christian
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - Mechanical properties of laser welded joints of wrought and heat treated PBF LB/M Inconel 718 parts depending on build direction
N2 - Laser-based Powder Bed Fusion of Metal (PBF-LB/M) is a broadly used metal additive manufacturing (AM) method for fabricating complex metallic parts, whose sizes are however limited by the build envelope of PBF-LB/M machines. Laser welding arises as a valid joining method for effectively integrating these AM parts into larger assemblies.
PBF-LB/M components must usually be stress-relieved before they can be separated from the build plate. An additional heat treatment can be beneficial for obtaining homogeneous mechanical properties across the seam or for the formation of desired precipitations in nickel-based-alloys.
Therefore, the tensile performance of laser welded hybrid (AM/wrought) and AM-AM tensile samples of Inconel 718 is examined after undergoing three different heat treatments and considering three relevant build directions. It can be shown that the build orientation is an influencing factor on weld properties even after two applied heat treatments.
T2 - Lasers in Manufacturing LiM 2023
CY - Munich, Germany
DA - 26.09.2023
KW - Inconel 718
KW - Laser welding
KW - PBF/LB-M
KW - Hybrid components
KW - Heat treatments
KW - Build direction
KW - Tensile performance
PY - 2023
SP - 1
EP - 10
PB - Proceedings Lasers in Manufacturing 2023
CY - München
AN - OPUS4-58394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaurasia, Prashant Kumar
T1 - Automated In-situ Monitoring and Analysis of Process Signatures and Build Profile During Arc-based Directed Energy Deposition
N2 - Automated in-situ synchronous monitoring and analysis of key process signatures during arc-based directed energy deposition (DED) process are the key challenges for layer-by-layer printing of large-scale parts. An attempt is presented here for real-time monitoring of process transients, deposit profile, and quantitative assessment of arc power, energy input and its influence on deposit dimensions. The workflow including setup, job generation and data analysis is fully automated in Python to allow large scale experiments with fast analysis results.
T2 - 2nd Online Young Welding Professional International Conference
CY - Online meeting
DA - 06.02.2025
KW - Additive Manufacturing
KW - Arc welding
KW - DED-arc
KW - Monitoring
KW - Deposition profile
PY - 2025
AN - OPUS4-62663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marquardt, R.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Functionally graded material for improved wear resistance manufactured by directed energy deposition
N2 - Protecting components against wear and corrosion is a common way to improve their lifetime. This can be achieved by coating them with a hardfacing material. Common coatings consist of materials such as tungsten carbide or cobalt-chromium alloys, also known as Stellite. Hardfacing materials can be deposited by welding methods like plasma welding or laser cladding. The discrete change of the base material to the hardfacing layer can lead to cracks and chipping. Studies showed a reduced risk of cracking when a functionally graded material is used to create a smooth transition between the base and the hardfacing. Gradings from austenitic steel to cobalt-chromium alloys are already known in the literature. However, there is no knowledge about austenitic- ferritic duplex steels as base material. Therefore, this study aims to demonstrate the feasibility of a functionally graded material from duplex steel to cobalt-chromium alloy with a new approach. By using powder-based directed energy deposition, a graded material with smooth material transition is manufactured additively. Cracking and porosity are examined through metallography. Microhardness measurements as well as the analysis of the chemical composition by energy dispersive X-ray spectroscopy and X-ray fluorescence are used to validate the build-up strategy.
KW - Additive manufacturing
KW - Functionally graded material
KW - Functionally graded additive manufacturing
KW - Directed energy deposition
KW - Laser metal deposition
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621683
DO - https://doi.org/10.1007/s40964-024-00879-4
SP - 1
EP - 6
PB - Springer Science and Business Media LLC
AN - OPUS4-62168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Pittner, Andreas
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Einlagiges MSG-Hochleistungsschweißen von dickwandigen Baustählen mit kontaktloser elektromagnetischer Schmelzbadsicherung
N2 - Diese Arbeit zeigt erstmals die Anwendung einer elektromagnetischen Schmelzbadsicherung beim einlagigen MSG-Schweißen von dickwandigen Stählen. Die innovativen Entwicklungen im Bereich des Lichtbogenschweißverfahrens ermöglichen eine Erhöhung der Abschmelzleistung, um die Einschweißtiefe zu steigern. Somit kann die Lagenanzahl reduziert und die Produktivität gesteigert werden. Allerdings besteht insbesondere beim einlagigen Schweißen von dickwandigen Bauteilen in PA-Position ein erhöhtes Risiko für das gravitationsbedingte Austropfen der Schmelze an der Wurzel. Zur Verhinderung werden Badsicherungen eingesetzt, die mechanisch angebracht und nach dem Schweißen entfernt werden müssen, was zeit- und kostenintensiv ist.
Die im Rahmen dieser Studie eingesetzte elektromagnetische Schmelzbadsicherung wirkt dem gravitationsbedingten Austropfen der Schmelze entgegen und kompensiert den hydrostatischen Druck. Sie wirkt kontaktlos, was im Gegensatz zu herkömmlichen Badsicherungen vorteilhaft ist, so dass auf eine zeit- und kostenintensive Nachbearbeitung der Schweißnahtwurzel verzichtet werden kann. Das auf extern angelegten oszillierenden Magnetfeldern beruhende Verfahren wird dabei unterhalb des zu schweißenden Bauteils positioniert. Die Magnetfeldlinien sind quer zur Schweißrichtung ausgerichtet, sodass längs zur Schweißrichtung Wirbelströme im Werkstück und eine stets nach oben gerichtete Lorentzkraft generiert werden. Mit Hilfe der elektromagnetischen Badsicherung konnten beim einlagigen MSG-Schweißen von bis zu 10 mm dicken Blechen die Tropfenbildung vermieden werden. Die innovative Technologie ermöglicht es, dickwandige Bauteile einlagig zu schweißen und reduziert die Nachbearbeitungszeiten und -kosten deutlich.
T2 - DVS Congress 2022 - Große Schweißtechnische Tagung
CY - Koblenz, Germany
DA - 19.09.2022
KW - Elektromagnetische Schmelzbadsicherung
KW - Hochleistungsschweißen
KW - MSG-Schweißen
PY - 2022
SN - 978-3-96144-189-1
VL - 382
SP - 640
EP - 645
PB - DVS Media GmbH
AN - OPUS4-56371
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Silbernagl, Dorothee
A1 - Szymoniak, Paulina
A1 - Tavasolyzadeh, Zeynab
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - Interpenetrating networks with tuned thermal and mechanical properties
N2 - Text Multiphoton lithography (MPL) has recently attracted significant research interest as a versatile tool capable of producing 2D and 3D micro- and nanoscopic features with high spatial resolution. The integrity of MPL microstructures, or their ability to respond to external stimuli, is of critical importance. However, achieving the desired properties of fabricated microcomponents for a specific application remains a challenge.
In this work, we present new MPL materials based on epoxy-acrylate interpenetrating networks (IPNs). We aim at 3D microstructures, whose properties can be easily tuned by varying the ratio of the IPN components and fabrication parameters (Figure 1). The resulting library of 3D microstructures was investigated for their thermal and mechanical properties using highly-sensitive space-resolved methods. Flash scanning calorimetry revealed the influence of both, IPN composition and fabrication parameters, on glass transition temperature and material fragility. AFM force-distance curve and intermodulation methods were used to characterize the mechanical properties with a lateral resolution of 1 micron and 4 nm, respectively. The deformation, stiffness and elastic behavior are discussed in detail in relation to the morphology. Moreover, we found that some 3D IPN microstructures exhibit fully elastic behavior. Our funding encourages the further development of IPN systems as versatile and easily tunable MPL materials.
T2 - Micro Nano Engineering (MNE conference)
CY - Berlin, Germany
DA - 25.09.2023
KW - Interpenetrating polymer network
KW - Multiphoton Lithography
KW - Two photon polymerisation
KW - Direct laser writing
KW - Polyethylene glycol diacrylate
PY - 2023
AN - OPUS4-58879
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Hybrid laser-arc welding of laser and plasma-cut 20 mm thick structural steels
N2 - It is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20 mm thick structural steel plates which were prepared by laser and plasma-cutting. Single-pass welds were conducted in butt-joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single-pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.
T2 - 74th IIW Annual Assembly and International Conference 2021
CY - Online meeting
DA - 07.07.2021
KW - Hybrid laser-arc welding
KW - Thick-walled steel
KW - Edge quality
KW - Gap bridgeability
KW - Misalignment of the edges
KW - Plasma-cutting
KW - Laser-cutting
PY - 2021
AN - OPUS4-53577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Chady, G.
A1 - Klawoon, Alexander
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
A1 - Robens-Radermacher, Annika
T1 - Efficient bead-on-plate weld model for parameter estimation towards effective wire arc additive manufacturing simulation
N2 - Despite the advances in hardware and software techniques, standard numerical methods fail in providing real-time simulations, especially for complex processes such as additive manufacturing applications. A real-time simulation enables process control through the combination of process monitoring and automated feedback, which increases the flexibil- ity and quality of a process. Typically, before producing a whole additive manufacturing structure, a simplified experiment in form of a bead-on- plate experiment is performed to get a first insight into the process and to set parameters suitably. In this work, a reduced order model for the transient thermal problem of the bead-on-plate weld simulation is devel- oped, allowing an efficient model calibration and control of the process. The proposed approach applies the proper generalized decomposition (PGD) method, a popular model order reduction technique, to decrease the computational effort of each model evaluation required multiple times in parameter estimation, control and optimization. The welding torch is modeled by a moving heat source, which leads to difficulties separating space and time, a key ingredient in PGD simulations. A novel approach for separating space and time is applied and extended to 3D problems allowing the derivation of an efficient separated representation of the tem- perature. The results are verified against a standard finite element model showing excellent agreement. The reduced order model is also leveraged in a Bayesian model parameter estimation setup, speeding up calibrations and ultimately leading to an optimized real-time simulation approach for welding experiment using synthetic as well as real measurement data.
KW - Ermüdung
PY - 2023
DO - https://doi.org/10.5281/zenodo.7456813
PB - Zenodo
CY - Geneva
AN - OPUS4-59651
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hartwig, Philipp
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Scheunemann, Lisa
A1 - Schröder, Jörg
A1 - Rethmeier, Michael
T1 - A Physically Motivated Heat Source Model for Laser Beam Welding
N2 - In this contribution, we present a physically motivated heat source model for the numerical modeling of laser beam welding processes. Since the calibration of existing heat source models, such as the conic or Goldak model, is difficult, the representation of the heat source using so-called Lamé curves has been established, relying on prior Computational Fluid Dynamics (CFD) simulations.
Lamé curves, which describe the melting isotherm, are used in a subsequent finite-element (FE) simulation to define a moving Dirichlet boundary condition, which prescribes a constant temperature in the melt pool. As an alternative to this approach, we developed a physically motivated heat source model, which prescribes the heat input as a body load directly. The new model also relies on prior CFD simulations to identify the melting isotherm. We demonstrate numerical results of the new heat source model on boundary-value problems from the field of laser beam welding and compare it with the prior CFD simulation and the results of the Lamé curve model and experimental data.
KW - Welding simulation
KW - Heat source models
KW - Laser beam welding
KW - Thermal analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600899
DO - https://doi.org/10.3390/met14040430
VL - 14
IS - 4
SP - 1
EP - 26
PB - MDPI
CY - Basel
AN - OPUS4-60089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.
A1 - Fedelich, Bernard
A1 - Finn, Monika
A1 - Künecke, Georgia
A1 - Rehmer, Birgit
A1 - Nolze, Gert
A1 - Leistner, C.
A1 - Petrushin, N.
A1 - Svetlov, I.
T1 - Investigation of Elastic Properties of the Single-Crystal Nickel-Base Superalloy CMSX-4 in the Temperature Interval between Room Temperature and 1300 °C
N2 - The elastic properties of the single-crystal nickel-base superalloy CMSX-4 used as a blade material in gas turbines were investigated by the sonic resonance method in the temperature interval between room temperature and 1300 °C. Elastic constants at such high temperatures are needed to model the mechanical behavior of blade material during manufacturing (hot isostatic pressing) as well as during technical accidents which may happen in service (overheating). High reliability of the results was achieved using specimens of different crystallographic orientations, exciting various vibration modes as well as precise measurement of the material density and thermal Expansion required for modeling the resonance frequencies by finite element method. Combining the results measured in this work and literature data the elastic constants of the gamma and gamma' phases were predicted.
This prediction was supported by measurement of the temperature dependence of the gamma'fraction.
All data obtained in this work are given in numerical or analytical forms and can be easily used for different scientific and engineering calculations.
KW - Nickel-base superalloys
KW - Single-crystals
KW - Characterization
KW - Elastic constants
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520972
DO - https://doi.org/10.3390/cryst11020152
VL - 11
IS - 2
SP - 152
PB - MDPI
AN - OPUS4-52097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Rethmeier, Michael
A1 - Gumenyuk, Andrey
T1 - Influence of edge‑deposited layers on mechanical and corrosion properties of laser beam welds of 15 mm thick AISI 2205 duplex stainless steel
N2 - AISI 2205 duplex stainless steel is used in a variety of industries, including the chemical and petrochemical industries. This is due to its high tensile strength combined with good ductility and corrosion resistance. However, in laser beam welding, these properties are negatively afected by the high cooling rates typical of the welding process. The resulting higher ferrrite content in the weld metal than in the base material leads to a reduction in the ductility and corrosion resistance of the welded joint. To overcome this problem, in this study, thick plates were coated by direct energy deposition (DED) prior to laser beam welding, whereas a duplex powder mixture containing a higher nickel concentration was used as a coating material. To improve the weld quality for the proposed two-step process, a method of additional material deposition instead of conventional tack weld was investigated. The resulting welded joints showed a well-balanced austenite to ferrite ratio and their properties and microstructure were verifed by metallographic analysis, electron backscatter difraction and Charpy impact testing. Using the standard ASTM G48 test method, it was found that the corrosion resistance of the welds was improved by a factor of four in average compared to the conventionally welded joints. The resulting properties, such as good ductility and corrosion resistance, of the welds with pre-coated edges showed good agreement with those of the base metal and confrmed the proposed two-step process as a promising alternative to the conventional approaches for welding thick duplex stainless steel plates.
KW - Laser metal deposition
KW - Laser beam welding
KW - Duplex steels
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581731
UR - https://rdcu.be/dlb6E
DO - https://doi.org/10.1007/s40194-023-01567-7
SN - 0043-2288
SP - 1
EP - 12
PB - Springer
AN - OPUS4-58173
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Kising, Pascal
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative artificial intelligence approach
N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A Conditional Variational Autoencoder (CVAE) model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-VAE model with the Evidence Lower Bound (ELBO) loss function and include Kullback-Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes.
T2 - International Congress of Applications of Lasers & Electro-Optics 2025
CY - Orlando, USA
DA - 12.10.2025
KW - Laser beam welding
KW - Generative artificial intelligence
KW - Machine learning
KW - numerical simulation
PY - 2025
SP - 1
EP - 10
AN - OPUS4-65075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of the weld pool geometry on solidification cracking in partial penetration high power laser beam welding
N2 - Solidification cracking is still a serious problem in laser beam welding, especially in the welding of thick-walled plates. The influence of weld pool geometry on solidification cracking in partial penetration welding of thick plates is investigated within scope of this study. Therefore, a specific experimental setup of steel and quartz glass in butt configuration and on the side with high-speed camera were used to record the weld pool shape. In addition, the influence of laser inclination angle on the weld pool geometry and on solidification crack formation was investigated. The results show a bulge in the weld pool root, which is separated from an upper region by a necking region. This leads to a case where there are three different longitudinal region lengths with different solidification zones. This temporal sequence of solidification strongly promotes the formation of solidification cracks in the weld root.
T2 - 12th CIRP Conference on photonic technologies (LANE 2022)
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser beam welding
KW - Partial penetration
KW - Weld pool shape
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563940
DO - https://doi.org/10.1016/j.procir.2022.08.174
VL - 111
SP - 397
EP - 400
PB - Elsevier B.V.
AN - OPUS4-56394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Improvement of the mechanical properties and corrosion resistance of laser welds on thick duplex plates by laser cladded buttering
N2 - Because of its excellent corrosion resistance, high tensile strength and
high ductility, duplex stainless steel 2205 offers many areas of application. Though laser beam welding accompanied by high cooling rates, duplex steels tend to perform higher ferrite contents in weld metal as the base metal, which leads to a reduction of ductility and corrosion resistance of the weld joint. To overcome this problem, a solution, based on buttering the plate edges by laser metal deposition (LMD) with material containing higher Ni concentrations prior to laser welding was suggested.
In this context different process parameters for LMD and different mixtures of duplex and nickel powder, were investigated. In a second step the possibility of welding those edges defect free while achieving balanced austenite-ferrite ratio was verified with metallographic analysis, Electron Backscatter Diffraction (EBSD) and impact testing according to Charpy. The improved corrosion resistance was observed with ASTM G48 standard test method.
T2 - X International Conference «Beam Technologies in Welding and Materials Processing»
CY - Odessa, Ukraine
DA - 7.09.2021
KW - Laser beam welding
KW - Laser metal deposition
KW - Duplex steels
PY - 2021
AN - OPUS4-53568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dávila, Josué
T1 - Influence of initial powder oxidation on mechanical properties of components fabricated via PBF-LB/M
N2 - The reuse of feedstock in laser powder bed fusion of metals (PBF-LB/M) enhances sustainability and reduces production costs but is limited by progressive degradation of the material [1]. One contributor to powder degradation is oxidation, even in protective atmospheres [2]. This study investigates how the initial oxidation state of Haynes 282, a nickel-based alloy for high-temperature applications, influences its performance at both ambient and elevated temperatures (850 °C). For this purpose, four feedstock batches with oxygen contents ranging from approximately 140 ppm to 1400 ppm were produced by controlled oxidation of virgin powder in a laboratory furnace.
Microscopy analysis revealed that higher oxidation levels promoted irregular melt pool morphology and increased surface roughness, accompanied by a reduction in grain size. Electron probe microanalysis revealed that the oxide layers observed on the surface of the manufactured specimens in the as-build condition consisted primarily of aluminium and titanium oxides. Oxygen analysis via inert gas fusion on heat-treated specimens measured approximately 90 ppm in material from virgin feedstock and approximately 600 ppm in material from the most oxidized batch. Notwithstanding these discrepancies, the part porosity and the room-temperature tensile properties, including ultimate strength and elongation at break, remained largely unaltered. Conversely, creep testing at elevated temperatures under application-relevant conditions showed a pronounced decline in creep resistance and a corresponding increase in creep strain with rising oxygen content. However, both the tensile strength and the deformation mechanisms observed in high-temperature tensile tests remained comparable across all batches. These findings indicate that while the use of oxidized powder is viable for less demanding service conditions, strict powder quality control is imperative when manufacturing components for high-temperature applications.
T2 - 5th Symposium on Materials and Additive Manufacturing
CY - Kassel, Germany
DA - 24.03.2026
KW - Additive manufacturing
KW - Powder bed fusion
KW - Powder oxidation
KW - Powder reuse
KW - High-temperature properties
KW - Creep resistance
PY - 2026
AN - OPUS4-65904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Fasselt, Janek Maria
A1 - Klötzer-Freese, Christian
A1 - Kruse, Tobias
A1 - Kleba-Ehrhardt, Rafael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Recycling nickel aluminium bronze grinding chips to feedstock for directed energy deposition via impact whirl milling: Investigation on processability, microstructure and mechanical properties
N2 - During the production of ship propellers, considerable quantities of grinding chips from nickel aluminium bronze areproduced. This paper examines the mechanical comminution of such chips via impact whirl milling and the utilization of twochip-powder batches as feedstock for a laser-based directed energy deposition process. The materials are characterized viadigital image analysis, standardized flowability tests, scanning electron microscopy and energy dispersive X-ray spectroscopyand are compared to conventional, gas atomized powder. The specimens deposited via directed energy deposition areanalyzed for density, hardness and microstructure and tensile properties for vertical and horizontal build up directions arecompared. At elevated mill rotation speeds, the comminution with impact whirl milling produced rounded particles, favorableflow properties and particle size distribution, making them suitable to deposit additive specimens. The microstructureexhibited characteristic martensitic phases due to the high cooling rates of the additive manufacturing process. The presenceof ceramic inclusions was observed in both the powder and on the tensile fracture surfaces, partly impairing the mechanicalproperties. However, specimens in the vertical build-up direction (Z) showed competitive tensile results, with 775 MPa intensile strength, 455 MPa in yield strength and 12.6 % elongation at break. The findings of this study indicate that recyclingof machining chips to additive manufacturing feedstock can be a viable option for reducing material costs and environmentalimpact.
KW - Nickel aluminium bronze
KW - Grinding chips
KW - Recycling
KW - Directed energy deposition
KW - Material characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651214
DO - https://doi.org/10.1016/j.addma.2025.104804
SN - 2214-8604
VL - 105
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Brunner-Schwer, C.
A1 - Knöfel, F.
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laserstrahlhybridschweissen von Türmen für Windkraftanlagen Ökonomische und ökologische Vorteile
N2 - Das Laserstrahlhybridschweißen ist beim Schweißen von Türmen für Windkraftanlagen eine Alternative zum Unterpulverschweißen von Dickblechen in Mehrlagentechnik und bietet hier ökonomische und ökologische Vorteile. Der industrielle Einsatz des Verfahrens ist jedoch durch prozessspezifische Herausforderungen eingeschränkt. Die im Beitrag beschriebene kontaktlose elektromagnetische Badstütze dient zur Erweiterung des Verfahrenspotenzials im Dickblechbereich >15 mm.
KW - Elektromagnetische Badstütze
KW - Laserhybridschweißen
KW - Windkraftanlagen
KW - Ökonomische und ökologische Vorteile
PY - 2022
VL - 7
SP - 340
EP - 347
PB - DVS Media GmbH
AN - OPUS4-56372
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Life Cycle Assessment of Fusion Welding Processes - A Case Study of Resistance Spot Welding Versus Laser Beam Welding
N2 - The high amount of resource consumption of fusion welding processes offers the potential to reduce their environmental impact. While the driving forces are known froma qualitative perspective, the quantitative assessment of the crucial parameters is not a trivial task. Therefore, herein, a welding-specific methodology to utilize life cycle assessment as a tool for evaluating the environmental impact of fusion welding processes is presented. In this context, two welding processes, resistance spot welding and laser beam welding, are analyzed for two different use cases.
These comprise the welding of shear test specimens and a cap profile made of electrogalvanized sheets of DC 05þ ZE (1.0312) as representative of an automotive application. For both welding processes, the main influences on the resulting environmental impact categories are evaluated and compared. The requirements for ecological efficient welding processes are discussed and implemented.
KW - Resistance spot welding
KW - Carbon dioxide footprint
KW - Environmental impact categories
KW - Laser beam welding
KW - Life cycle assessment
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566458
DO - https://doi.org/10.1002/adem.202101343
SN - 1438-1656
VL - 24
IS - 6
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Batahgy, A.
A1 - Elkousy, M.
A1 - Al-Rahman, A.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Gook, S.
T1 - Retaining Mechanical Properties of GMA-Welded Joints of 9%Ni Steel Using Experimentally Produced Matching Ferritic Filler Metal
N2 - Motivated by the loss of tensile strength in 9%Ni steel arc-welded joints performed using commercially available Ni-based austenitic filler metals, the viability of retaining tensile strength using an experimentally produced matching ferritic filler metal was confirmed. Compared to the austenitic Ni-based filler metal (685 MPa), higher tensile strength in gas metal arc (GMA) welded joints was achieved using a ferritic filler metal (749 MPa) due to its microstructure being similar to the base metal (645 MPa). The microstructure of hard martensite resulted in an impact energy of 71 J (-196 °C), which was two times higher than the specified minimum value of _>34 J. The
tensile and impact strength of the welded joint is affected not only by its microstructure, but also by the degree of its mechanical mismatch depending on the type of filler metal. Welds with a harder microstructure and less mechanical mismatch are important for achieving an adequate combination of tensile strength and notched impact strength. This is achievable with the cost-effective ferritic filler metal. A more desirable combination of mechanical properties is guaranteed by applying low preheating temperature (200 °C), which is a more practicable and economical solution compared to the high post-weld heat treatment (PWHT) temperature (580 °C) suggested by other research.
KW - 9%Ni steel
KW - Ni-based austenitic filler metal
KW - Mechanical mismatching
KW - Microstructure
KW - Post-weld heat treatment
KW - Preheating
KW - Matching ferritic filler metal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564610
DO - https://doi.org/10.3390/ma15238538
SN - 1996-1944
VL - 15
IS - 23
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-56461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, S.
A1 - Midik, A.
A1 - Biegler, M.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Joining 30 mm Thick Shipbuilding Steel Plates EH36 Using a Process Combination of Hybrid Laser Arc Welding and Submerged Arc Welding
N2 - This article presents a cost-effective and reliable method for welding 30 mm thick sheets of shipbuilding steel EH36. The method proposes to perform butt welding in a two-run technique using hybrid laser arc welding (HLAW) and submerged arc welding (SAW). The HLAW is performed as a partial penetration weld with a penetration depth of approximately 25 mm. The SAWis carried out as a second run on the opposite side. With a SAWpenetration depth of 8 mm, the weld cross-section is closed with the reliable intersection of both passes. The advantages of the proposed welding method are: no need for forming of the HLAW root; the SAW pass can effectively eliminate pores in the HLAWroot; the high stability of the welding process regarding the preparation quality of the weld edges. Plasma cut edges can be welded without lack of fusion defects. The weld quality achieved is confirmed by destructive tests.
KW - Shipbuilding steel
KW - Hybrid laser arc welding
KW - Submerged arc welding
KW - Hardness
KW - Bending test
KW - Two-run welding technique
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556090
DO - https://doi.org/10.3390/jmmp6040084
SN - 2504-4494
VL - 6
IS - 4
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-55609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Bähring, S.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Quality Prediction in Directed Energy Deposition Using Artificial Neural Networks Based on Process Signals
N2 - The Directed Energy Deposition process is used in a wide range of applications including the repair, coating or modification of existing structures and the additive manufacturing of individual parts. As the process is frequently applied in the aerospace industry, the requirements for quality assurance are extremely high. Therefore, more and more sensor systems are being implemented for process monitoring. To evaluate the generated data, suitable methods must be developed. A solution, in this context, was the application of artificial neural networks (ANNs). This article demonstrates how measurement data can be used as input data for ANNs. The measurement data were generated using a pyrometer, an emission spectrometer, a camera (Charge-Coupled Device) and a laser scanner. First, a concept for the extraction of relevant features from dynamic measurement data series was presented. The developed method was then applied to generate a data set for the quality prediction of various geometries, including weld beads, coatings and cubes. The results were compared to ANNs trained with process parameters such as laser power, scan speed and powder mass flow. It was shown that the use of measurement data provides additional value. Neural networks trained with measurement data achieve significantly higher prediction accuracy, especially for more complex geometries.
KW - DED
KW - Artificial neural network
KW - Data preparation
KW - Quality assurance
KW - Process monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555063
DO - https://doi.org/10.3390/app12083955
SN - 2076-3417
VL - 12
IS - 8
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Study on Duplex Stainless Steel Powder Compositions forthe Coating of Thick Plates for Laser Beam Welding
N2 - Duplex stainless steels combine the positive properties of its two phases, austenite and ferrite. Due to its good corrosion resistance, high tensile strength and good ductility it has multiple applications. But laser beam welding of duplex steels changes the balanced phase distribution in favor of ferrite. This results in a higher vulnerability to corrosion and a lower ductility. In this study different powder combinations consisting of duplex and nickel for coating layers by laser metal deposition are investigated. Afterwards laser tracks are welded, and the temperature cycles measured. The ferrite content of the tracks are analyzed by feritscope, metallographic analysis and Electron Backscatter Diffraction. The goal is the development of a powder mixture allowing for a duplex microstructure in a two-step process, where firstly the edges of the weld partners are coated with the powder mixture by LMD and secondly those edges are laser beam welded. The powder mixture identified by the pretests is tested in the two-step process and analyzed by metallographic analysis, energy dispersive X-ray spectroscopy and Vickers hardness tests. The resulting weld seams show a balanced duplex microstructure with a homogenous nickel distribution and a hardness of the weld seam similar to the base material.
KW - Duplex AISI 2205
KW - Stainless Steel
KW - Laser Beam Welding
KW - Nickel
KW - Laser Metal Deposition
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554663
DO - https://doi.org/10.1002/adem.202101327
SN - 1438-1656
VL - 24
IS - 6
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding
N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. First, the local variation of the solidification sequence of the weld pool causes an increase in the hot-cracking susceptibility due to a locally delayed solidification. Second, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g., during the welding with filler materials, is blocked. This leads to a non-homogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results that were supported by selected experimental validation results.
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
KW - Porosity
KW - Numerical process simulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557759
DO - https://doi.org/10.2351/7.0000733
SN - 1042-346X
VL - 34
IS - 4
SP - 1
EP - 7
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-55775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brunner-Schwer, C.
A1 - Simón Muzás, Juan
A1 - Biegler, M.
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - Laser Welding of L-PBF AM components out of Inconel 718
N2 - With regard to efficient production, it is desirable to combine the respective advantages of additively and conventionally manufactured components. Particularly in the case of large-volume components that also include filigree or complex structures, it makes sense to divide the overall part into individual elements, which afterwards have to be joined by welding.
The following research represents a first step in fundamentally investigating and characterizing the joint welding of Laser Powder Bed Fusion (L-PBF) components made of Inconel 718. For this purpose, bead-on-plate welds were performed on plates manufactured using the L-PBF process and compared with the conventionally manufactured material. Conventional laser beam welding was used as welding process. The weld geometry was investigated as a function of the L-PBF build-up orientation. It was found that the welding depth and weld geometry differ depending on this orientation and in comparison to the conventional material.
T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser Welding
KW - L-PBF
KW - PBF-LB/M
KW - Seam geometry
KW - Bead-on-plate welds
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560012
DO - https://doi.org/10.1016/j.procir.2022.08.072
SN - 2212-8271
VL - 111
SP - 92
EP - 96
PB - Elsevier B.V.
AN - OPUS4-56001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Improvement of Charpy impact toughness by using an AC magnet backing system for laser hybrid welding of thick S690QL steels
N2 - The study deals with the influence of the heat input and the resulting cooling times on the microstructure and Charpy impact toughness of single-pass laser hybrid welded 20-mm thick high-strength steel S690QL. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured in-situ using a pyrometer and an optical fibre in three different depths of the seam where Charpy impact test specimens were also later taken. Thereby, three different heat inputs from 1.3 kJ/mm to 2 kJ/mm were investigated. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required impact toughness of 38 J/cm2 could be reached in dependance on applied heat input, especially at the heat input of 1.6 kJ/mm.
T2 - 12th CIRP conference on photonic technologies [lane 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Thick-plate welding
KW - Laser hybrid welding
KW - Electromagnetic backing
KW - Charpy impact toughness
KW - Thermal cycles
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563731
DO - https://doi.org/10.1016/j.procir.2022.08.067
VL - 111
SP - 462
EP - 465
PB - Elsevier B.V.
AN - OPUS4-56373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Miliūtė, Aistė
ED - Bustamante, Joana
ED - Karafiludis, Stephanos
ED - Zöllner, Moritz
ED - Eddah, Mustapha
ED - Emmerling, Franziska
ED - Mieller, Björn
ED - George, Janine
ED - Stawski, Tomasz
T1 - Synthesis and phase purity of the negative thermal expansion material ZrV2O7
N2 - Synthesis of pure, homogeneous, and reproducible materials is key for the comprehensive understanding, design, and tailoring of material properties. In this study, we focus on the synthesis of ZrV2O7, a material known for its negative thermal expansion properties. We investigate the influence of solid-state and wet chemistry synthesis methods on the purity and homogeneity of ZrV2O7 samples. Our findings indicate that different synthesis methods significantly impact the material's characteristics. The solid-state reaction provided high-purity material through extended milling time and repeated calcination cycles, while the sol-gel reaction enabled a “near-atomic” level of mixing and, therefore, homogenous phase-pure ZrV2O7. We confirmed purity via X-ray diffraction and Raman spectroscopy, highlighting differences between phase-pure and multiphase ceramics. These analytical techniques allowed us to distinguish subtle differences in the structure of the material. Based on ab initio simulated phonon data, we were able to interpret the Raman spectra and visualise Raman active atom vibrations. We show that phase purity enables the unbiased characterisation of material properties such as negative thermal expansion.
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - XRD
KW - Raman
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613643
DO - https://doi.org/10.26434/chemrxiv-2024-d4sj9
SN - 2573-2293
VL - 2024
SP - 1
EP - 60
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-61364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srinivasan, Krishnanand
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser Metal Deposition of Rene 80—Microstructure and Solidification Behavior Modelling
N2 - New developments in nickel-based superalloys and production methods, such as the use of additive manufacturing (AM), can result in innovative designs for turbines. It is crucial to understand how the material behaves during the AM process to advance the industrial use of these techniques. An analytical model based on reaction–diffusion formalism is developed to better explain the solidification behavior of the material during laser metal deposition (LMD). The well-known Scheil–Gulliver theory has some drawbacks, such as the assumption of equilibrium at the solid–liquid interface, which is addressed by this method. The solidified fractions under the Scheil model and the pure equilibrium model are calculated using CALPHAD simulations. A differential scanning calorimeter is used to measure the heat flow during the solid–liquid phase transformation, the result of which is further converted to solidified fractions. The analytical model is compared with all the other models for validation.
KW - Laser metal deposition
KW - Solidification behavior
KW - Additive manufacturing
KW - Analytical model
KW - Nickel‐based superalloy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612095
DO - https://doi.org/10.3390/mi15101234
SN - 2072-666X
VL - 15
IS - 10
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-61209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Determination of critical local straining conditions for solidification cracking at laser beam welding by experimental and numerical methods
N2 - AbstractThe phenomenon of solidification cracking has been the subject of numerous research projects over the years. Great efforts have been made to understand the fundamentals of hot cracking. It is generally agreed that solidification cracks form in the solidification range between the liquidus and solidus temperatures under the combination of thermal, metallurgical and mechanical factors. There is still a need to determine the time‐resolved strain distribution in the crack‐sensitive region in order to analyse the local critical conditions for solidification cracking phenomena. This was a strong motivation for the development of a measurement system used in this study to estimate the local strains and strain rates in the zone where the solidification crack is expected to occur. The laser beam welding experiments were conducted using the Controlled‐Tensile‐Weldability test (CTW test) to apply an external strain condition during welding to generate solidification cracks. The CTW test is a test method for investigating the susceptibility of laser‐welded joints to solidification cracking, in which the sample can be subjected to a defined strain at a defined strain rate during welding.In combination with experimental investigations, numerical simulations provide spatially detailed and time‐dependent information about the strain development during the welding process, especially regarding the critical conditions for solidification cracking. Therefore, this tool was also used in the present study to evaluate the accuracy of measurement methods and to estimate experimentally derived values and their concrete influence on the formation of solidification cracks. By integrating experimental methods and numerical simulations, this study investigates the spatially resolved and temporally changing development of strain during welding, with a particular focus on the critical conditions that lead to the formation of solidification cracks. The use of numerical simulations serves a dual purpose by validating the accuracy of measurement methods and examining experimentally determined values for their actual influence on the formation of solidification cracks. A three‐dimensional finite element (FE) model implemented with ANSYS is used to simulate strains and stresses during welding. The credibility of the model was first established by validation using experimental temperature measurements. Subsequently, structural simulations were carried out under external load. The results of the simulations showed commendable agreement with the strain measurements performed using the developed technique.
KW - Laser beam welding
KW - Solidification cracking
KW - FEM simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612044
DO - https://doi.org/10.1002/pamm.202400020
SN - 1617-7061
VL - 24
IS - 2
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-61204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Assessment of keyhole stability in laser beam welding with external magnetic field using numerical simulation
N2 - The challenge of understanding the physical mechanisms behind porosity reduction by a magnetic field during laser beam welding (LBW) is partly due to the difficulty in quantitatively evaluating keyhole stability. The commonly used index, such as keyhole depth, is typically one-dimensional, which is insufficient to capture the dynamic and three-dimensional fluctuations of the keyhole. In this paper, by utilizing a 3D multiphysical model of LBW with magnetic field, a novel keyhole geometry reconstruction algorithm has been developed to describe the keyhole profile and its fluctuation in a statistical manner to evaluate keyhole stability quantitatively. An equivalent diameter is proposed in this algorithm to reduce the irregularity of the keyhole geometry. The calculation results indicate that the time-averaged keyhole shape over 300 ms in the LBWof steel is conical, regardless of the application of an external magnetic field, which provides a more representative shape. Meanwhile, it is observed from the statistical aspect that the keyhole diameter becomes smaller, except the top part, under the influence of the magnetic field. The standard deviation of the equivalent diameter can be used as a physical variable to assess the keyhole stability quantitatively. The application of an external magnetic field can produce a noticeable reduction of the standard deviation of the equivalent diameter, namely, stabilizing the keyhole during LBW of steel. However, the different contribution from the keyhole stability affected by a magnetic field in suppressing porosity is different with materials.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 04.11.2024
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Keyhole shape
KW - Keyhole stability
KW - Magnetic field
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614984
DO - https://doi.org/10.2351/7.0001528
VL - 36
IS - 4
SP - 1
EP - 7
PB - AIP Publishing
CY - Melville, NY
AN - OPUS4-61498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Assessment of keyhole stability in laser beam welding with external magnetic field using numerical simulation
N2 - The challenge of understanding the physical mechanisms behind porosity reduction by a magnetic field during laser beam welding (LBW) is partly due to the difficulty in quantitatively evaluating keyhole stability. The commonly used index, such as keyhole depth, is typically one-dimensional, which is insufficient to capture the dynamic and three-dimensional fluctuations of the keyhole. In this paper, by utilizing a 3D multiphysical model of LBW with magnetic field, a novel keyhole geometry reconstruction algorithm has been developed to describe the keyhole profile and its fluctuation in a statistical manner to evaluate keyhole stability quantitatively. An equivalent diameter is proposed in this algorithm to reduce the irregularity of the keyhole geometry. The calculation results indicate that the time-averaged keyhole shape over 300 ms in the LBW of steel is conical, regardless of the application of an external magnetic field, which provides a more representative shape. Meanwhile, it is observed from the statistical aspect that the keyhole diameter becomes smaller, except the top part, under the influence of the magnetic field. The standard deviation of the equivalent diameter can be used as a physical variable to assess the keyhole stability quantitatively. The application of an external magnetic field can produce a noticeable reduction of the standard deviation of the equivalent diameter, namely, stabilizing the keyhole during LBW of steel. However, the different contribution from the keyhole stability affected by a magnetic field in suppressing porosity is different with materials.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Hollywood, Los Angeles, USA
DA - 04.11.2024
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Keyhole shape
KW - Keyhole stability
KW - Magnetic field
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616024
DO - https://doi.org/10.2351/7.0001528
VL - 36
IS - 4
SP - 1
EP - 7
PB - AIP Publishing
AN - OPUS4-61602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gumenyuk, Andrey
A1 - Bakir, Nasim
A1 - Rethmeier, Michael
T1 - Two-colour thermography for measurement of temperature distribution in laser beam welding
N2 - Solidification cracking is a frequently observed phenomenon in laser beam welding of austenitic stainless steels and other metallic alloys. Characterisation of cracking susceptibility requires knowledge of the precise and spatially resolved temperature distribution near the solidification front in the welding process. Thermography is a standard tool that provides a qualitative estimate of the 2D temperature field. The general disadvantage of this method is its dependence on the emission characteristics of the measured object. For welding applications, these can vary significantly in the temperature range above and below the melting temperature. For this purpose, we have developed a thermography-based measurement technique using a SWIR camera system in combination with two narrow bandpass filters that use the principle of two-wavelength pyrometry to estimate absolute temperature values. This technique was used to determine the temperature distributions and gradients near the solidification front of laser-welded austenitic steel. The results were validated by other measurements.
KW - Laser beam welding
KW - Two-colour thermography
KW - Solidification cracking
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612070
DO - https://doi.org/10.1016/j.procir.2024.08.155
VL - 124
SP - 468
EP - 471
PB - Elsevier BV
AN - OPUS4-61207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical studies of magnetohydrodynamic technology in suppressing process porosity during laser beam welding
N2 - The magnetohydrodynamic (MHD) technology is employed to mitigate the porosity problem during partial penetration laser beam welding (LBW) of 10 mm thick aluminum alloy. The effectiveness and universal applicability of the MHD technology in reducing porosity during the LBW process are confirmed by a reduction in the porosity ratio of more than 89%. A transient 3D multi-physical model coupled with the MHD effect has been developed to investigate the suppression mechanism of process porosity. Due to the influence of Lorentz force, there is an obvious change in the weld pool length. This change widens the escaping channel of bubbles escaping from the weld pool. The application of an oscillating magnetic field changes the fluid flow pattern noticeably, whose influence on the formation of porosity defects is highly complicated and nonlinear.
T2 - CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Aluminum alloy
KW - Process Porosity
KW - Porosity suppression
KW - Magnetohydrodynamic technology
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616053
DO - https://doi.org/10.1016/j.procir.2024.08.175
VL - 124
SP - 565
EP - 569
PB - Elsevier B.V.
AN - OPUS4-61605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Putra, Stephen Nugraha
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Pusbatzkies, Pablo
A1 - Rethmeier, Michael
T1 - Elucidation of the laser beam energy attenuation by the vapor plume formation during high-power laser beam welding
N2 - In high-power laser beam welding, a common phenomenon is the formation of a keyhole caused by the rapid evaporation of the material. Under atmospheric pressure, this evaporation generates a vapor plume that interacts with the laser beam, leading to energy attenuation and scattering of the laser radiation along its path. These interactions affect the stability of the process and the overall weld quality. This study investigates the influence of the vapor plume on the weld pool and keyhole dynamics during high-power laser beam welding of AlMg3 aluminum alloy through experimental and numerical approaches. The primary goal is to identify key vapor plume characteristics, particularly its length fluctuations, and to improve the accuracy of the numerical models. To achieve this, an algorithm was developed for the automated measurement of the vapor plume length using high-speed imaging and advanced data processing techniques. The measured plume length is then used to estimate additional vapor heating and laser energy attenuation using the Beer–Lambert law. A refined numerical CFD model, incorporating 3D transient heat transfer, fluid flow, and ray tracing, was developed to evaluate the vapor plume’s impact. Results show that already the time-averaged plume length effectively captures its transient influence and aligns well with experimental weld seam geometries. Additionally, energy scattering and absorption caused by the vapor plume led to a wider weld pool at the top surface. The study also shows an increased percentage of keyhole collapses due to the reduced laser power absorption at the keyhole bottom, further highlighting the importance of accurately modeling vapor plume effects.
T2 - International Congress of Applications of Lasers & Electro-Optics 2025
CY - Orlando, USA
DA - 12.10.2025
KW - Laser beam welding
KW - Vapor plume formation
KW - Weld pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2026
DO - https://doi.org/10.2351/7.0001863
SN - 1938-1387
IS - 38
SP - 012001-1
EP - 012001-9
PB - Laser Institute of America
AN - OPUS4-64949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winterkorn, R.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Wire Arc Additive Manufacturing von einer neuartigen, höherfesten Al-Mg-Si Legierungen
N2 - Der Einsatz von Aluminiumlegierungen als Konstruktionswerkstoff hat in den letzten Jahrzehnten aufgrund seines überlegenen Festigkeits-/ Gewichtsverhältnisses zugenommen. Dabei spielen höherfeste aushärtbare Al-Mg-Si-Legierungen eine wichtige Rolle.
Dieser Beitrag konzentriert sich auf die additive Fertigung von Prinzipbauteilen aus einer Al-Mg-Si-Aluminiumlegierung mittels Wire + Arc Additive Manufacturing. Werkstoffe dieses Legierungssystems weisen eine ausgeprägte Heißrissanfälligkeit auf, weshalb das artgleiche Fügen dieser Materialien, mittels Metallschutzgasschweißen, heutzutage immer noch eine Herausforderung darstellt. Kommerzielle Al-Mg-Si-Schweißdrähte sind am Markt nicht verfügbar.
In dieser Arbeit wird die Anwendbarkeit eines neuartigen Al-Mg-Si-Schweißdrahtes mit zusätzlichen kornfeinenden Elementen für die additive Fertigung mittels MSG-Verfahren gezeigt. Dazu wird der Zusammenhang von verwendeten Prozessparametern und der resultierenden Bauteilqualität untersucht, wobei die Größe und Verteilung von Poren sowie die Kornmorphologie analysiert werden. Darüber hinaus wird der Einfluss einer T6 Wärmenachbehandlung auf die mechanischen Eigenschaften des Werkstoffes untersucht und ein Vergleich zum entsprechenden Referenzmaterial (Knetlegierung) gezogen.
T2 - 40. Assistentenseminar Fügetechnik
CY - Braulage, Germany
DA - 25.09.2019
KW - WAAM
KW - Al-Mg-Si
PY - 2020
SN - 978-3-96144-071-9
VL - 357
SP - 68
EP - 77
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-52901
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Braun, Ulrike
A1 - Bannick, C.-G.
A1 - Bednarz, M.
A1 - Herper, D.
A1 - Knefel, M.
T1 - TED-GC/MS: Schnelle Bestimmung von Mikroplastik-Massegehalten in verschiedenen Proben
N2 - Zur Ermittlung von Mikroplastik-Gehalten in verschiedenen Umweltmatrices ist ein schnelles Detektionsverfahren für die Routineanalytik notwendig. Ein solches Verfahren wird hier in Form der ThermoExtraktion/Desorption-GasChromatographie/ MassenSpektroskopie (TED-GC/MS) vorgestellt. Neben grundlegenden verfahrensspezifischen Erläuterungen zur Identifizierung und Quantifizierung von Mikroplastik werden auch exemplarische Beispiele aus unterschiedlichen Umweltkompartimenten und Produkten dargestellt. Neu vorgestellt wird ein neues Verfahren zur Analytik von Flaschenwasser. Dazu wurde ein Messfiltertiegel entwickelt, der besonders für Proben mit geringen Gehalten an abfiltrierbaren Stoffen geeignet ist
KW - Mikroplasik
KW - Mikroplastik-Analyse
KW - TED-GC/MS
KW - Thermoanalytische Verfahren
KW - Mikroplastik-Massengehalte
PY - 2020
VL - 2020
IS - 02
SP - 55
EP - 57
PB - Gesellschaft Deutscher Chemiker (GDCh)
CY - Frankfurt am Main
AN - OPUS4-50835
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
T1 - Wire arc additive manufacturing of high strength AL-MG-SI alloys
N2 - Gas metal arc-based direct energy deposition (DED) additive manufacturing technologies hold significant promise for producing large-scale metal components. However, determining optimal process parameters to achieve the desired near-net shape design and mechanical performance is a complex challenge due to the intricate interplay between process parameters and material properties. This presentation highlights the use of a newly developed solid welding wire doped with TiB to improve grain refinement in metals deposited via DED-Arc for high-strength precipitation-hardening AlMgSi aluminum alloys. This wire stems from our initial metallurgical investigations into grain refinement in aluminum weld metals.
The research emphasizes the relationship between process parameters and component quality, aiming to uncover the mechanisms that influence performance. This is essential for establishing a reliable range of parameters that meet quality standards, many of which are derived from traditional welding practices.
Component quality was assessed by studying pore size, pore distribution, and grain morphology. To further enhance the mechanical properties of the deposited material, post-weld heat treatments—including solution treatment, quenching, and artificial aging—were applied. The study also explores how different heat treatment strategies affect the final mechanical properties.
To validate the feasibility of 3D printing high-strength aluminum alloys, a more complex demonstrator component was fabricated. The results demonstrate that DED-Arc technology can produce large aluminum parts with a quality comparable to subtractive manufacturing techniques.
Furthermore, the entire additive manufacturing workflow has been digitally integrated, enabling full traceability of all key process steps. This digital integration is critical for ensuring reliable quality assessments of the finished components.
T2 - 77th IIW Annual Assembly and International Conference Joint Meeting of C-I, C-IV, and C-XII
CY - Rhodos, Greece
DA - 07.07.2024
KW - DED-Arc
KW - High-strength aluminium alloys
KW - Porosity assessment
KW - Component testing
KW - CT-analyses
PY - 2024
AN - OPUS4-62014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Walterbos, Luc
T1 - Double trouble: exploring the chemical landscape of halide double perovskites
N2 - Halide Double Perovskites (HDPs) are an emerging class of materials with chemical formula A2BB’X6 with possible applications in photovoltaics, X-ray detection, sensing, photocatalysis and spintronics.. However, with more than 40,000 potential HDP compositions, much of the chemical landscape remains unexplored. We have generated a database of spin-polarized, hybrid functional (HSE06) electronic structure data of all HPDs with A=Cs that are predicted to be stable based on a tolerance-factor analysis. Our high-throughput workflow also consists or a chemical bonding and orbital projection analysis based on LOBSTER (ww.cohp.de), leading to a comprehensivedatabase of electronic, magnetic and chemical bonding properties of >2700 HDP compositions, which can serve as a starting point for material design and discovery via interpretable machine learning techniques, which we use to identify unexpected trends and relations in the chemical landscape.
T2 - Psi-k 2025
CY - Lausanne, Swiss
DA - 25.08.2025
KW - Materials design
KW - Halide perovskite
KW - Halide double perovskite
KW - High-throughput
KW - Hybrid functional
PY - 2025
AN - OPUS4-64009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Plarre, Rüdiger
A1 - Zocca, Andrea
A1 - Spitzer, Andrea
A1 - Benemann, Sigrid
A1 - Gorbushina, Anna
A1 - Li, Y.
A1 - Waske, Anja
A1 - Funk, Alexander
A1 - Wilgig, Janka
A1 - Günster, Jens
T1 - Searching for biological feedstock material: 3D printing of wood particles from house borer and drywood termite frass
N2 - Frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects) of larvae of the European house borer (EHB) and of drywood termites was tested as a natural and novel feedstock for 3D-printing of wood-based materials. Small particles produced by the drywood termite Incisitermes marginipennis and the EHB Hylotrupes bajulus during feeding in construction timber, were used. Frass is a powdery material of particularly consistent quality that is essentially biologically processed wood mixed with debris of wood and faeces. The filigree-like particles flow easily permitting the build-up of woodbased structures in a layer wise fashion using the Binder Jetting printing process. The Quality of powders produced by different insect species was compared along with the processing steps and properties of the printed parts. Drywood termite frass with a Hausner Ratio HR = 1.1 with ρBulk = 0.67 g/cm3 and ρTap = 0.74 g/cm3 was perfectly suited to deposition of uniformly packed layers in 3D printing. We suggest that a variety of naturally available feedstocks could be used in environmentally responsible approaches to scientific material sciences/additive manufacturing.
KW - 3D printing
KW - X-ray tomographic
KW - SEM micrography
KW - Drywood termite
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521517
DO - https://doi.org/10.1371/journal.pone.0246511
VL - 16
IS - 2
SP - e0246511
AN - OPUS4-52151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design
N2 - Despite significant progress, computational materials design still faces major challenges—particularly when simulating advanced and chemically complex materials with the accuracy of density functional theory (DFT) or beyond.[1] To overcome these limitations, machine learning (ML) methods have gained considerable traction in recent years.
We have developed robust data-generation strategies to support the creation and benchmarking of new ML models.[2] In this talk, I will highlight methods for large-scale quantum-chemical bonding analysis and workflows for ML interatomic potentials.
Our work demonstrates that quantum-chemical bonding properties can be incorporated into ML models to predict phononic properties.[3] This approach enables large-scale validation of expected correlations—such as the link between bonding strength and force constants or thermal conductivities.
Furthermore, we have built an automated training framework for machine-learned interatomic potentials (autoplex).[4] Initial workflows include random structure searches, suitable for general-purpose potentials, as well as specialized workflows targeting ML potentials with accurate phonon properties.
While atomistic simulations are highly effective for certain material properties, others—such as magnetism or synthesizability—remain challenging. In these cases, promising strategies include benchmarking established ab initio methods against chemical heuristics or developing new ML models primarily based on experimental data.[5,6]
T2 - MATSUS Spring 2026
CY - Barcelona, Spain
DA - 24.03.2026
KW - Materials Design
KW - High-througput
KW - Bonding properties
KW - Thermal conductivity
KW - Amorphous materials
KW - Crystallisation
PY - 2026
AN - OPUS4-65734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials
N2 - Understanding the chemistry and nature of individual chemical bonds is essential for materials design. Bonding analysis via the LOBSTER software package has provided valuable insights into the properties of materials for thermoelectric and catalysis applications. Thus, the data generated from
bonding analysis becomes an invaluable asset that could be utilized as features in large-scale data analysis and machine learning of material properties. However, no systematic studies exist that conducted high-throughput materials simulations to curate and validate bonding data obtained from LOBSTER. Here we present an approach to constructing such a large database consisting of quantum-chemical bonding information.
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Ireland
DA - 03.07.2023
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
AN - OPUS4-57889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Namrata, Jaykhedkara
A1 - George, Janine
T1 - Atomistic interaction at the solid interface between Li6PS5Cl and Li metal
N2 - Solid-state batteries offer higher energy density and improved safety than conventional lithium-ion cells with flammable liquid electrolytes, [1] but poor interfacial compatibility at the solid-electrolyte (SE)|electrode interface, especially with lithium metal anodes, remains a major challenge. [2] To gain a deeper understanding of the structural and chemical factors governing the formation and growth of this interface, we selected Li6PS5Cl (SE) and Li metal anode as prototype materials. In this work, we begin by performing ab initio molecular dynamics accelerated by machine-learning potentials in VASP, to obtain lattice parameters and bulk moduli of the bulk Li6PS5Cl and Li metal phases, thereby quantifying lattice-mismatch strain, compressibility differences, and their thermal evolution. We then analyze the atomic structure and coordination environments at the Li6PS5Cl|Li interface, which is carefully constructed for the [100] orientation for both SE and Li, allowing the lowest possible strain (see Fig. 1). Dominant bonding motifs are identified using Crystal Orbital Hamilton Population [3] analysis via LOBSTER.[4] Radial distribution functions of the interface are compared with those of the respective bulk phases in the 200-400 K range to elucidate temperature-driven structural rearrangements. This combined analysis reveals how interfacial bonding evolves with temperature and provides critical insight into chemical and mechanical stability at the interface. Our findings offer a quantitative framework for correlating bulk properties with interfacial structure, thereby informing the design of more robust SEs and engineering strategies to improve interfacial compatibility.
T2 - 12th Workshop “Lithium-Sulfur Batteries”
CY - Dresden, Germany
DA - 17.11.2025
KW - Solid-state batteries
KW - Interface chemistry
KW - Machine learning-molecuar dynamics
PY - 2025
AN - OPUS4-64804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design
N2 - This talk first introduces students to the Materials Acceleration Platforms and Advanced Materials Characterization at BAM. Then, it motivates high-throuhgput screening for materials discovery and advanced materials simulations based on these core topics. Then four different research studies are presentend: evaluation of generative models, synthesizability prediction via PU learning, acceleration of materials property predictions with bonding analysis and advanced materials simulations supported by automatically trained machine learning potentials.
T2 - Guest Lecture in MSE 403/1003, a Seminar in the Curriculum of the University of Toronto
CY - Online meeting
DA - 13.02.2026
KW - Automation
KW - Materials Acceleration Platforms
KW - Machine Learning
KW - Workflows
KW - Phonons
KW - Bonding Analysis
KW - Thermal Conductivity
PY - 2026
AN - OPUS4-65514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, R.
A1 - Osayi, J.
A1 - Kmieciak, S.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Verschleißschutz einer Schneckengeometrie durch funktional gradierte Materialien
N2 - Hochbelastete Stahlbauteile lassen sich durch Auftragen von Kobalt-Chrom Legierungen vor Verschleiß schüt-zen. Die plötzliche Änderung der Materialeigenschaften führt jedoch zu Spannungen und Rissen im Anbindungs-bereich. Daraus resultierende Abplatzungen stellen eine Gefahr für die Funktionsfähigkeit der Maschine und damit für Mensch und Umwelt dar. Um die Belastbarkeit der Schutzschicht zu verbessern, kann die Anbindung durch einen gradierten Materialübergang optimiert werden. Diese funktional gradierten Materialien können mit-tels pulverbasiertem Directed Energy Deposition aufgetragen werden. Die Methodik zum Aufbau und zur Quali-tätssicherung solcher Materialien wurde in vorangegangenen Arbeiten für dickwandige Geometrien gezeigt. Für dünnwandige Geometrien ist die Anwendbarkeit bisher unzureichend untersucht worden. Diese Arbeit zeigt am Beispiel einer dünnwandigen gradierten Schneckengeometrie die Einsatzfähigkeit der Methodik. Dafür wird die Gefügestruktur der Gradierung auf Fehler untersucht und der Härteverlauf gemessen. Außerdem wird die relative Dichte anhand eines bereits trainierten neuronalen Netzes vorhergesagt und mit einer Porositätsuntersuchung verglichen.
T2 - 14. Tagung Verschleiß- und Korrosionsschutz von Bauteilen durch Auftragschweißen
CY - Halle (Saale), Germany
DA - 12.06.2024
KW - Directed Enery Deposition
KW - Funktionally Graded Material
KW - Additive Manufacturing
KW - DED
KW - FGM
KW - AM
PY - 2024
AN - OPUS4-62688
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böhne, C.
A1 - Meschut, G.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - The Influence of Electrode Indentation Rate on LME Formation during RSW
N2 - During resistance spot welding of zinc-coated advanced high-strength steels (AHSSs) for automotive production, liquid metal embrittlement (LME) cracking may occur in the event of a combination of various unfavorable influences. In this study, the interactions of different welding current levels and weld times on the tendency for LME cracking in third-generation AHSSs were investigated. LME manifested itself as high penetration cracks around the circumference of the spot welds for welding currents closely below the expulsion limit. At the same time, the observed tendency for LME cracking showed no direct correlation with the overall heat input of the investigated welding processes. To identify a reliable indicator of the tendency for LME cracking, the local strain rate at the origin of the observed cracks was analyzed over the course of the welding process via finite element simulation. While the local strain rate showed a good correlation with the process-specific LME cracking tendency, it was difficult to interpret due to its discontinuous course. Therefore, based on the experimental measurement of electrode displacement during welding, electrode indentation velocity was proposed as a descriptive indicator for quantifying cracking tendency.
KW - Liquid Metal Embrittlement (LME)
KW - Crack
KW - Resistance Spot Welding (RSW)
KW - Advanced High-Strength Steel (AHSS)
KW - Welding Current
KW - Heat Input
KW - Simulation
PY - 2022
DO - https://doi.org/10.29391/2022.101.015
SN - 0043-2296
VL - 101
IS - 7
SP - 197-s
EP - 207-s
PB - American Welding Society
CY - New York, NY [u.a.]
AN - OPUS4-55600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, Julius
A1 - Beret, Alexander
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Ökobilanzierung in der additiven Fertigung – Laser- vs. Elektronenstrahl
N2 - Die additive Fertigung gewinnt für industrielle Anwendungen zunehmend an Bedeutung. In diesem Zusammenhang sind Verfahren der Directed Energy Deposition (DED) besonders gefragt, um hohe Aufbauraten zu erreichen. Neben den bekannten laserstrahlbasierten Verfahren hat auch der Elektronenstrahl die industrielle Marktreife erreicht. Das Wire Electron Beam Additive Manufacturing bietet zum Beispiel Vorteile bei der Verarbeitung von Kupferwerkstoffen. In der Literatur wird die höhere Energieeffizienz und die daraus resultierende Verbesserung der CO2-Bilanz des Elektronenstrahls hervorgehoben. Es fehlt jedoch an praktischen Studien mit Messdaten, um das Potenzial der Technologie zu quantifizieren. In dieser Arbeit wird eine vergleichende Ökobilanz zwischen der additiven Fertigung mit Draht und Elektronenstrahl (DED-EB) und der additiven Fertigung mit Laserstrahl und Pulver (DED-LB) durchgeführt. Dazu werden die Ressourcen für die Herstellung ermittelt, ein Testbauteil mit beiden Verfahren hergestellt und der gesamte Energieverbrauch gemessen. Die Umweltauswirkungen werden dann mit den Faktoren Treibhauspotenzial (GWP100), Ozonbildungspotenzial (POCP), Versauerungspotenzial (AP), Eutrophierungspotenzial (EP) abgeschätzt. Es zeigt sich, dass das Wire Electron Beam Additive Manufacturing durch einen deutlich geringeren Energiebedarf gekennzeichnet ist. Darüber hinaus gewährleistet die Verwendung von Draht eine größere Ressourceneffizienz, was zu insgesamt besseren Ökobilanzergebnissen führt.
KW - Ökobilanzierung (LCA)
KW - Additive Fertigung
KW - Directed Energy Deposition
KW - Kupfer
KW - Wire Electron Beam Additive Manufacturing
PY - 2024
SP - 26
EP - 32
AN - OPUS4-62234
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raute, J.
A1 - Seitz, G.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Wire Electron Beam Additive Manufacturing von niedriglegierten Zinnbronzen – Erreichbare Bauteileigenschaften und Prozessmerkmale
N2 - Die Additive Fertigung gewinnt zunehmend an Bedeutung für die Verarbeitung von Kupferwerkstoffen im industriellen Umfeld. Hierbei wird verstärkt auf drahtförmige Ausgangswerkstoffe gesetzt, da diese Vorteile im Handling bieten, bereits aus der Schweißtechnik bekannt sind und sich zumeist durch geringere Beschaffungskosten auszeichnen. In den letzten Jahren entwickelte sich unter den drahtbasierten Verfahren der Directed-Energy-Deposition (DED) eine Prozessvariante unter Nutzung des Elektronenstrahls zur industriellen Marktreife. Dabei zeigt die Technologie Wire Electron Beam Additive Manufacturing (DED-EB) besondere Vorteile gegenüber anderen DED-Prozessen für die Anwendung an Kupfer. Um das Verfahren einem breiten Anwenderkreis in der Industrie zugänglich zu machen, fehlen jedoch Daten zu Leistungsfähigkeit, Prozessgrenzen und Anwendungsmöglichkeit- en. Die vorliegende Untersuchung beschäftigt sich mit dieser Problemstellung am Beispiel der Legierung CuSn1MnSi. Über mehrstufige Testschweißungen werden die physikalisch möglichen Prozessgrenzen ermittelt und Rückschlüsse über die Eignung der Parameter zum additiven Aufbau gezogen. An verschiedenen additiv gefertigten Probekörpern werden anschließend Kennwerte für Aufbaurate, Härte, Mikrostruktur, Oberflächenqualität sowie mechanische Festigkeitswerte ermittelt. Es zeigt sich, dass das die durch DED-EB hergestellten Proben, trotz des groben Gefüges sowie der thermischen Belastung im Aufbauprozess, in ihren Eigenschaften gut mit den Spezifikationen des Ausgangsmaterials übereinstimmen.
T2 - Kupfersymposium 2023
CY - Jena, Germany
DA - 29.11.2023
KW - Wire Electron Beam Additive Manufacturing
KW - DED-EB
KW - CuSn1
KW - Additive Fertigung
PY - 2023
SN - 978-3-910411-03-6
SP - 28
EP - 33
PB - Kupferverband e. V.
AN - OPUS4-59118
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
T1 - Theoretical and experimental development of negative thermal expansion material ZrV2O7
N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which stands out for its remarkable isotropic unit cell contraction over a broad temperature range (130°C < T < 800°C). This enables the fabrication of composites where the overall expansion coefficient can be tailored to a specific negative, positive, or neutral value. Consequently, such composite materials are attractive for many device applications because they can compensate for damage caused by thermal expansion. They are relevant to optical systems, electronic and biomedical applications.
In this study, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation (QHA), temperature-dependent effective harmonic potentials (TDEP)[5]) in combination with experimental methods to follow and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder, microstructure, and defects. In analytical techniques that can provide structural information such as pair distribution function analysis (PDF), X-ray diffraction (XRD), and Extended X-ray Absorption Fine Structure (EXAFS), molecules and atoms are fit geometrically without consideration of atom interactions. Therefore, in combination with these methods, we also consider potential energy surfaces and conclude what structures are likely to form energetically in the full NTE temperature range, in addition to fitting experimental data geometrically. We also optimise experimentally fitted structures to their lowest energy configurations and re-generate comparative data to observe what differences would be visible experimentally.
T2 - XLVIII International Congress of Theoretical Chemists of Latin Expression
CY - Cartagena de Indias, Colombia
DA - 13.07.2025
KW - NTE
KW - Ab initio
KW - QHA
KW - TDEP
KW - anharmonicity
PY - 2025
AN - OPUS4-63873
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design
N2 - Despite significant progress, computational materials design still faces challenges, especially when simulating large systems needed to describe defects, interfaces, or amorphous states with the accuracy of density functional theory (DFT) or beyond.[1] To address these limitations, machine learning (ML) methods have become increasingly popular in recent years. In this talk, I will present how we’ve developed robust data generation strategies that support the creation and benchmarking of new ML models.[2] I’ll focus on methods for large-scale quantum-chemical bonding analysis and workflows for ML interatomic potentials. We’ve shown that quantum-chemical bonding properties can be used in ML models to predict phononic properties.[3] This enables us to validate several expected correlations— such as the link between bonding strength and force constants—on a large scale. Additionally, we’ve built an automated training framework for machine-learned interatomic potentials (autoplex).[4] Initial workflows include random structure searches, which are well-suited for general-purpose potentials, as well as workflows tailored to ML potentials with accurate phonon properties. While atomistic simulations are highly effective for certain material properties, others— like magnetism or synthesizability—remain difficult. In these cases, it’s promising to benchmark established ab initio methods against chemical heuristics or to develop new ML models based primarily on experimental data.[5,6]
T2 - SusML (Sustainable Machine Learning Workshop)
CY - Dresden, Germany
DA - 29.09.2025
KW - Materials Design
KW - Materials Acceleration Platforms
KW - Automation
KW - Workflows
KW - Machine Learned Interatomic Potentials
KW - Synthesizability
KW - Magnetism
PY - 2025
AN - OPUS4-64244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust data generation, heuristics and machine learning for materials design
N2 - Machine learning (ML) offers new routes to overcome the limitations of density functional theory (DFT) for advanced materials. We present data-generation strategies and workflows for ML interatomic potentials, including large-scale quantum-chemical bonding analysis.[1,2,3] Incorporating bonding descriptors into ML models enables prediction of phononic properties and validation of correlations between bonding strength, force constants, and thermal conductivity.[3] We introduce autoplex, an automated framework for training ML potentials, supporting general-purpose and phonon-focused workflows.[4] These developments provide a basis for fine-tuning foundation models for thermal transport at reduced cost.[5] For properties such as magnetism or synthesizability, we discuss complementary approaches, comparing ab initio methods with chemical heuristics and experimental data-driven ML models.[6,7]Our work advances scalable, accurate simulations for materials discovery.
T2 - DPG Dresden, Condensed Matter
CY - Dresden, Germany
DA - 10.03.2026
KW - Materials Design
KW - Materials Acceleration Platforms
KW - Advanced materials simulations
KW - Automation
KW - High-throughput
KW - Thermal Conductivity
KW - Chemical Bonding Analysis
KW - Phonons
KW - Amorphous Materials
PY - 2026
AN - OPUS4-65648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of oscillating magnetic field on the keyhole stability in deep penetration laser beam welding
N2 - The stability of the keyhole decreases for deep penetrated high-power laser beam welding. The keyhole tends to collapse with increasing laser power and e.g. keyhole induced porosity can occur. This study deals with the observation of the keyhole during high-power laser beam welding in partial penetration mode by means of a high-speed camera. A butt configuration of 25 mm thick structural steel and transparent quartz glass was used for the experiments. An oscillating magnetic field was applied perpendicular to the welding direction on the root side of the steel plate. The keyhole was highlighted with a coaxial diode laser. It was ascertained that the stability of the keyhole and the weld penetration depth were increased by applying an oscillating magnetic field with an oscillating frequency of 1.2 kHz and a magnetic flux density of 50 mT.
KW - Magnetic field
KW - Laser beam welding
KW - Keyhole stability
PY - 2021
DO - https://doi.org/10.1016/j.optlastec.2020.106715
SN - 0030-3992
VL - 135
SP - 106715
PB - Elsevier Ltd.
AN - OPUS4-52007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Analysis of microstructure and mechanical properties of single-pass laser hybrid welded thick-walled steels up to 30 mm with contactless electromagnetic backing
N2 - The study deals with the influence of the heat input on the thermal cycles, the microstructure and the mechanical properties for laser-hybrid welded steels of S355J2 with thicknesses up to 30 mm using a 20-kW high-power laser with contactless electromagnetic backing. The focus is on the change of the mechanical properties over the seam thickness. Therefore, the impact toughness and tensile strength were tested in different depths. Based on the experiments, a heat input of 1.3 kJ/mm - 1.6 kJ/mm, 2 kJ/mm - 2.4 kJ/mm and 3.7 kJ/mm were recommended when single-pass welding of 20 mm, 25 mm and 30 mm with a 20-kW laser in regard to the minimum requirements of the mechanical properties, respectively. Lower heat inputs led to undesired microstructure consisting of martensite, hardening and deteriorated impact toughness, where higher heat inputs led to grain-coarsening and even loss of impact strength due to the formation of retained-austenite on the grain boundaries.
T2 - EMPOrIA 2023 - International Joint Conference
CY - Aachen, Germany
DA - 16.05.2023
KW - Laser hybrid welding
KW - Electromagnetic backing
KW - Thermal cycles
KW - Charpy impact toughness
KW - Thick-plate welding
PY - 2023
AN - OPUS4-58614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strommer, Bettina
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
A1 - Böhning, Martin
T1 - Networking Skills: The Effect of Graphene on the Crosslinking of Natural Rubber Nanocomposites with Sulfur and Peroxide Systems
N2 - Tailored crosslinking in elastomers is crucial for their technical applications. The incorporation of nanoparticles with high surface-to-volume ratios not only leads to the formation of physical networks and influences the ultimate performance of nanocomposites, but it also affects the chemical crosslinking reactions. The influence of few-layer graphene (FLG) on the crosslinking behavior of natural rubber is investigated. Four different curing systems, two sulfur-based with different accelerator-to-sulfur ratios, and two peroxide-based with different peroxide concentrations, are combined with different FLG contents. Using differential scanning calorimetry (DSC), vulcametry (MDR) and swelling measurements, the results show an accelerating effect of FLG on the kinetics of the sulfur-based curing systems, with an exothermic reaction peak in DSC shifted to lower temperatures and lower scorch and curing times in the MDR. While a higher accelerator-to-sulfur ratio in combination with FLG leads to reduced crosslinking densities, the peroxide crosslinkers are hardly affected by the presence of FLG. The good agreement of crosslink densities obtained from the swelling behavior confirms the suitability of vulcameter measurements for monitoring the complex vulcanization process of such nanocomposite systems in a simple and efficient way. The reinforcing effect of FLG shows the highest relative improvements in weakly crosslinked nanocomposites.
KW - Nanocomposite
KW - Elastomers
KW - Graphene
KW - Crosslinking
KW - Network
KW - Rubber
KW - Vulcanization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560409
DO - https://doi.org/10.3390/polym14204363
VL - 14
IS - 20
PB - MDPI
AN - OPUS4-56040
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Balderas-Xicohtencatl, R.
A1 - Villajos, José Antonio
A1 - Casabán, J.
A1 - Wong, D.
A1 - Maiwald, Michael
A1 - Hirscher, M.
T1 - ZIF‑8 Pellets as a Robust Material for Hydrogen Cryo-Adsorption Tanks
N2 - Cryoadsorption on the inner surface of porous materials is a promising solution for safe, fast, and reversible hydrogen storage. Within the class of highly porous metal−organic frameworks, zeolitic imidazolate frameworks (ZIFs) show high thermal, chemical, and mechanical stability. In this study, we selected ZIF-8 synthesized mechanochemically by twin-screw extrusion as powder and pellets. The hydrogen storage capacity at 77 K and up to 100 bar has been analyzed in two laboratories applying three different measurement setups showing a high reproducibility. Pelletizing ZIF-8 increases the packing density close to the corresponding value for a single crystal without loss of porosity, resulting in an improved volumetric hydrogen storage capacity close to the upper limit for a single crystal. The high volumetric uptake combined with a low and constant heat of adsorption provides ca. 31 g of usable hydrogen per liter of pellet assuming a temperature−pressure swing adsorption process between 77 K − 100 bar and 117 K − 5 bar. Cycling experiments do not indicate any degradation in storage capacity. The excellent stability during preparation, handling, and operation of ZIF-8 pellets demonstrates its potential as a robust adsorbent material for technical application in pilot- and full-scale adsorption vessel prototypes.
KW - Hydrogen adsorption storage
KW - Metal−organic frameworks
KW - ZIF-8
KW - Cryoadsorption
KW - Hydrogen Storage
KW - MefHySto
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569473
DO - https://doi.org/10.1021/acsaem.2c03719
SN - 2574-0962
SP - 1
EP - 8
PB - ACS Publications
CY - Washington DC
AN - OPUS4-56947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schubnell, J.
A1 - Konidena, S. K.
A1 - Jung, M.
A1 - Braun, M.
A1 - Ehlers, S.
A1 - Madia, Mauro
A1 - Kannengießer, Thomas
A1 - Löschner, D.
T1 - Approach for the probabilistic fatigue assessment of welded joints based on the local geometry of the weld seam
N2 - Welded joints show large variation of the weld toe geometry along the weld seam, which is one important reason for the comparably large scatter in fatigue life. Therefore, it is crucial to take the local geometry at the weld toe into account, to reduce the conservatism in fatigue assessment of welded joints. This study is based on the IBESS procedure for the calculation of the fatigue strength, whereby the evaluation of local geometrical parameters is carried out by means of 3D surface scans. The approach is validated against 26 fatigue test series. The fatigue life is in general overpredicted, whereas good agreement is achieved for high stress ratio (R = 0.5). A sensitivity analysis conducted with IBESS shows that weld toe radii ρ < 2 mm and flank angle α < 30° have a significant influence on the calculated fatigue strength. In contrast to this, no strong correlation between ρ and the fatigue strength was determined experimentally in this study.
KW - 3D Scanning
KW - Fatigue Strength
KW - Fracture Mechanics
KW - IBESS Approach
KW - Local Weld Geometry
KW - Welded Joints
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585700
DO - https://doi.org/10.1111/ffe.14170
SN - 8756-758X
SP - 1
EP - 20
PB - Wiley
AN - OPUS4-58570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strommer, Bettina
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
A1 - Böhning, Martin
T1 - The quantification of anisotropy in graphene/natural rubber nanocomposites: Evaluation of the aspect ratio, concentration, and crosslinking
N2 - In the processing of nanocomposites, high shear stresses at elevated tempera-tures orient two-dimensional nanoparticles like graphene. This orientationleads to anisotropic mechanical, thermal or barrier properties of the nanocom-posite. This anisotropy is addressed in this study by comparing graphene (few-layer graphene, FLG) with a nanoscaled carbon black (nCB) at a filler contentof 3 phr, by varying the vulcanization, and by comparing different FLG con-tents. Transmission electron microscopy gives insight into the qualitative ori-entation in the nanocomposite with FLG or nCB. The storage moduli paralleland normal to the orientation reveal the direction dependency of reinforce-ment through dynamic mechanical analysis (DMA). Dimensional swellingmeasurements show a restriction of the expansion parallel to the FLG orienta-tion, and an increased expansion normal to the orientation. The vulcanizationsystem and crosslinking determine the respective level of property values, andhigher crosslinking densities increase the anisotropy in DMA resulting invalues of up to 2.9 for the quantified anisotropy factor. With increasing FLGcontent, the anisotropy increases. A comparison of the results reveals swellingmeasurements as the most suitable method for the determination of anisot-ropy. Compared to recent literature, the presented processing induces higheranisotropy, leading to higher reinforcing effects in the direction of orientation
KW - Natural rubber
KW - Graphene
KW - Nanocomposite
KW - Mechanical properties
KW - Swelling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571522
DO - https://doi.org/10.1002/app.53753
SN - 1097-4628
VL - 140
IS - 16
SP - 1
EP - 15
PB - Wiley online library
CY - Hoboken, New Jersey (USA)
AN - OPUS4-57152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Han, Ying
A1 - Kruse, Julius
A1 - Rosalie, Julian
A1 - Radners, J.
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Influence of mean stress and overaging on fatigue life of aluminum alloy EN AW-2618A
N2 - Fatigue tests were performed on the forged aluminum alloy EN AW-2618A in the T61 state. Different stress ratios (R = -1, R = 0.1) were selected to study the influence of mean stress on fatigue life. Two overaged states (10 h/230 ◦C, 1000 h/230 ◦C) were also tested to investigate the influence of overaging on fatigue life. Transmission electron microscopy (TEM) was used to characterize the precipitates (S-phase), which are mainly responsible for the strength of the alloy. A fractographic analysis was also performed to determine the failure mode. Overaging reduces the fatigue life compared to the T61 state. The longer the aging time, the lower the fatigue resistance. The reason is the decrease in (yield) strength, which correlates with the radius of the S-phase: the precipitate radius increases by a factor of approximately two for the overaged states compared to the initial state. The analysis of the fracture surfaces showed crack initiation occurs predominantly on the outer surface and is
associated with the primary phases.
KW - Aluminum alloys
KW - Aging
KW - Fatigue
KW - Microstructure
KW - Electron microscopy
KW - S-Phase
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583708
DO - https://doi.org/10.1016/j.msea.2023.145660
SN - 0921-5093
VL - 886
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-58370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Ávila Calderón, Luis
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
A1 - Bruno, Giovanni
T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion
N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed.
KW - Creep
KW - Computed Tomography
KW - PBF-LB/M/316L
KW - Laser Powder Bed Fusion
KW - Microstructure
KW - AISI 316L
KW - Additive Manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574127
DO - https://doi.org/10.1002/adem.202201581
SP - 1
EP - 9
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-57412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Jürgens, Maria
A1 - Uhlemann, Patrick
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Experimental data from service-like creep-fatigue experiments on grade P92 steel
N2 - This article refers to the research article entitled “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times” [1]. It presents experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress. Such service-like (SL) tests with additional long-term stress- and strain-controlled dwell times are non-standard, rare, and expensive, making these data very valuable. They may be used to approximate cyclic softening in the technically relevant range, for the design of complex SL experiments, or for detailed analyses of stress-strain hystereses (e.g., for stress or strain partitioning methods, for the determination of hysteresis energies (work), inelastic strain components, etc.). In addition, the latter analyses may supply important input for advanced parametric lifetime modeling of components under creep-fatigue loading or model calibration parameters.
KW - Tempered martensite-ferritic steel
KW - Creep
KW - Stress relaxation
KW - Creep-fatigue
KW - Dwell times
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578407
DO - https://doi.org/10.1016/j.dib.2023.109333
SN - 2352-3409
VL - 49
SP - 1
EP - 9
PB - Elsevier Inc.
AN - OPUS4-57840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rockenhäuser, Christian
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Brinell-Hardness data (HBW 2.5/62.5) of aluminum alloy EN AW-2618A after different aging times and temperatures
N2 - The article covers data on the Brinell hardness of the forged precipitation-hardened aluminum alloy EN AW-2618A in the initial T61 condition (i. e. slightly underaged) and after isothermal aging for up to 25,0 0 0 h at aging temperatures between 160 °C and 350 °C. In addition, the hardness was determined on specimens after creep testing at 190 °C and various stresses. The hardness decreases with increasing ag- ing time due to the microstructural evolution of the harden- ing precipitates. The drop occurs faster the higher the aging temperature. Aging under creep load additionally accelerates the hardness decrease.
KW - Aluminum alloy
KW - EN AW-2618A
KW - Brinell hardness
KW - Aging
KW - Creep
KW - Ostwald ripening
KW - Reheating
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567611
DO - https://doi.org/10.1016/j.dib.2022.108830
SN - 2352-3409
VL - 46
PB - Elsevier Inc.
AN - OPUS4-56761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Abel, Andreas
T1 - Microstructural and mechanical characterisation of cast Fe-Al-Mo-Ti-B alloys
N2 - With the advent of variable renewable energies, long-term energy storage capacities and flexible power generation technologies will be required for reliable grid stability. Hence, power plant technologies and turbomachinery components will continue to be developed and employed for efficient re-conversion of stored energy. With the introduction of new working fluids for higher thermal efficiencies, the working conditions of exposed components and materials will require higher corrosion resistance, but with the same mechanical performance, manufacturability and cost. Intermetallic iron aluminide alloys with their outstanding oxidation and corrosion resistance and good high-temperature properties depict a possible candidate for use in high-temperature structural applications. A quinary Fe-26Al-4Mo-0.5Ti-1B solid-solution alloy with eutectic particle hardening particularly demonstrated competitive mechanical properties compared to high-alloy P92 steels in previous studies. To derive standard material specifications with industrially relevant casting strategies, centrifugal investment-cast Fe-25Al-3.7Mo-0.4Ti-1B was characterised with respect to microstructure, thermophysical properties and mechanical properties under quasi-static tensile and creep loading up to 700 °C. Compared to P92 steel, the alloy demonstrated superior tensile strength above 550 °C and lower creep rates at 650 °C if stresses increase above 170 MPa. At lower temperatures though, the mechanical properties were inferior to P92 steel and related Fe-Al-Mo-Ti-B alloys, which was correlated to large grain sizes, a high tendency to surface and bulk cracking and a pronounced effect of tension-compression asymmetry. In further studies on alloy composition with varying Al, Mo and B concentration, a non-linear relationship of solid-solution hardening with solute Mo concentration was found. In this regard, halving Mo was the most effective measure for reducing brittleness without decreasing strength at room and elevated temperatures. Higher solidification rates and grain refinement down to 30 µm by die casting had a positive effect on ambient tensile strength, but were not achievable by investment casting. Dilatometry and hardness measurements indicated a low thermal vacancy hardening effect which was less sensitive to low-temperature annealing than in B2 FeAl alloys. Although mechanical properties up to 550 °C could be considerably improved by alloy development and processing, ductility at room temperature generally remained below 1%, necessitating substantial design margins for components from Fe-Al-Mo-Ti-B alloys. Despite the inherent limitations of alloy and casting process, the gained insights will help to prioritise future areas of research to mature cost-effective higher-order Fe
Al alloys for high-temperature structural applications.
KW - Hardness
KW - Iron aluminide alloy
KW - Micro structure
KW - Tensile strength
KW - Creep strength
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632810
DO - https://doi.org/10.5445/IR/1000181739
SP - 1
EP - 179
PB - Karlsruher Institut für Technologie (KIT)
CY - Karlsruhe
AN - OPUS4-63281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Han, Ying
A1 - Fritsch, Tobias
A1 - Hejazi, Bardia
A1 - Ulbricht, Alexander
A1 - Skrotzki, Birgit
A1 - Bruno, Giovanni
T1 - X-ray computed tomography quantifies primary phases and reveals crack morphology in high-cycle fatigue of aluminum alloy EN AW-2618A
N2 - Since the introduction of high-strength aluminum alloys understanding their fatigue behavior is of high interest for the structural integrity of engineering components, in this context, the alloy EN AW-2618A gains its high strength from both nanometer size precipitates and micrometer size primary phases. The latter phases are often identified as crack initiation sites. In this study, it uses a combination of synchrotron and laboratory-based X-ray computed tomography to image and quantify such primary phases and the fatigue cracks appearing in interrupted tests. Based on the gray-level differences in the synchrotron X-ray computed tomography scans, this study is able to distinguish low- and high-absorbing particles. The dominant (volume fraction >99%) high absorbing primary phase can be quantified in good agreement with results of Thermo-Calc calculations. To image the fatigue crack, laboratory X-ray computed tomography scans are performed at different tensile loads to open the crack. The results show that with an appropriate crack opening tensile load, the fatigue crack morphology can be reliably revealed. Based on these results, the influence of the primary phases on the fatigue crack initiation and propagation are discussed.
KW - X-ray computed tomography
KW - Fatigue
KW - Aluminum
KW - Primary phases
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632724
DO - https://doi.org/10.1002/adem.202500235
SN - 1527-2648
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-63272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Han, Ying
A1 - Schriever, Sina
A1 - von Hartrott, Philipp
A1 - Rockenhäuser, Christian
A1 - Skrotzki, Birgit
T1 - Creep dataset for aluminum alloy EN AW-2618A in the T61 and overaged condition 1000 h/190 °C
N2 - The article presents creep data for the precipitation-hardened aluminum alloy EN AW-2618A, which was tested in its initial slightly underaged T61 condition and after being aged at 190 °C for 1000 h. The creep test temperatures ranged between 160 °C and 230 °C, and the applied initial stresses between 40 MPa and 290 MPa. The testing times reached up to 4700 h. 19 data sets are provided as creep strain vs. time series. A data schema originally developed to manage creep reference data of a single-crystalline nickel-based superalloy was adapted for the research data set of the polycrystalline aluminum alloy and used to enrich the test data with extensive metadata. The dataset can be used to calibrate and validate creep models. The creep data supplement the hardness and microstructure data that have been previously published.
KW - Aluminum alloy EN AW-2618A
KW - Aging
KW - Overaging
KW - High temperature
KW - Creep
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641517
DO - https://doi.org/10.1016/j.dib.2025.112054
SN - 2352-3409
VL - 62
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-64151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
A1 - Jokisch, Torsten
A1 - Olbricht, Jürgen
A1 - Fedelich, Bernard
T1 - Fatigue crack growth in nickel-based alloy 247DS with side-brazed pre-sintered preform
N2 - Pre-sintered preform (PSP) brazing is employed in the repair of gas turbine components made of nickel-based alloys, including restoring the surface and dimensions of turbine blades and vanes. This study investigates the fatigue crack growth (FCG) behavior of Alloy 247DS specimens with side-brazed PSP material, mimicking a typical sandwich structure formed during such repairs. FCG tests were conducted at an elevated temperature of 950 °C and a stress ratio (R) of 0.1 on specimens with PSP layer thicknesses of 1.5 mm, 2 mm, 3 mm, and 4.5 mm to assess the influence of PSP thickness on fatigue crack growth behavior. Fractographic and metallographic analyses were performed to elucidate the underlying crack growth mechanisms and the microstructural characteristics of both materials. The results revealed that a crack consistently initiated in the PSP material, originating from the starter notch, particularly at the specimen corner during the pre-cracking phase. Additionally, crack propagation in the PSP material consistently advanced ahead of the crack in the Alloy 247DS. This crack growth behavior is attributed to the difference in elastic properties and microstructural differences between the PSP and base material. Metallographic analysis revealed the presence of porosity and brittle precipitates within the PSP material, which led to faster intergranular crack growth. Conversely, Alloy 247DS exhibited transgranular crack growth, contributing to the observed crack propagation behavior. This study demonstrates the applicability of standard FCG testing methods and an approach to characterize the FCG behavior in sandwich specimens, where crack growth occurs simultaneously in both materials, providing a preliminary understanding of crack growth behavior in Alloy 247DS with side-brazed PSP.
KW - High-temperature fatigue crack growth (FCG)
KW - Nickel-based alloys
KW - Alloy 247DS
KW - Pre-Sintered Preform (PSP)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629783
DO - https://doi.org/10.1016/j.ijfatigue.2025.108961
VL - 197
SP - 1
EP - 13
PB - Elsevier BV
AN - OPUS4-62978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Durlo Tambara, Luís Urbano
A1 - Dehn, F.
A1 - Gluth, Gregor
T1 - Effect of alkali-activated concrete composition on carbonation rate under accelerated and natural conditions
N2 - While alkali-activated binders offer certain advantages over traditional Portland cement binders, particu¬larly in terms of resistance against chemical attacks and potentially environmental footprint, their degradation mechanisms remain incompletely understood at present, specifically carbonation. Thus, this study investigates the impact of natural and accelerated carbonation (1% and 4% CO2) on three different compositions of alkali-activated concretes: 100% calcined clay (C100) binder, 100% ground blast furnace slag (S100) binder, and a 40% calcined clay and 60% blast furnace slag blend (C40S60). C100 concretes exhibit faster carbonation kinetics, with five times greater natural carbonation depths than S100. This difference diminishes under accelerated carbonation, showing a 1.5 times difference for 1% CO2 and complete carbonation for 4% CO2 at 90 days. The results thus confirm that accelerated carbonation testing of low-Ca alkali-activated concretes yields results that are not representative of natural carbonation. The C40S60 sample demonstrates a carbonation profile similar to a CEM I concrete, i.e., a high carbonation resistance. Microstructure analysis indicates the formation of three polymorphs of calcium carbonate for S100 (calcite, vaterite, and aragonite), with a higher CO2 concentration favouring aragonite over vaterite. C100 exhibits no calcium carbonates; instead, sodium carbonates form, including trona for 4% CO2 and natrite for both accelerated tests. C40S60 shows calcium and sodium carbonates, although to a lesser extent, containing predominantly calcite and minor signals of natrite. Suitable compositions, like C40S60, prove as effective during natural or accelerated carbonation tests as conventional Portland cement concrete.
T2 - RILEM Spring Convention 2024
CY - Milan, Italy
DA - 10.04.2024
KW - Alkali-activated concrete
KW - Carbonation
KW - Calcined clay
KW - Slag
KW - Durability
PY - 2024
AN - OPUS4-59915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strommer, Bettina
T1 - Natural Rubber Nanocomposites via Optimized Latex Premixing and Conventional Technical Processing
N2 - Creation of highly functional materials and replacement of high amounts of conventional fillers are driving forces for the development of nanocomposites. Besides the type and properties of nanoparticles, their dispersing in the elastomeric matrix and the stability of this dispersion through all processing steps are the
main factors for the resulting performance of the produced material. Therefore, a preparation chain via latex premixing to a highly filled masterbatch, followed by conventional technical processing is to be developed.
Three types of carbon-based particles are characterized as such (SEM, Raman Spectroscopy, BET specific surface area) and in combination with natural rubber, as nanocomposites (TEM. Hardness, Abrasion resistance, Compression set, Cone calorimetry).
All of the studied particles lead to an improvement in the investigated mechanical properties, the extent of reinforcement depends strongly on the specific surface of the particle interacting with the elastomeric matrix in combination with their shape.
T2 - DKG Elastomer Symposium
CY - Online meeting
DA - 28.06.2021
KW - Processing
KW - Elastomers
KW - Nanocomposites
KW - Graphene
KW - Nanoparticles
KW - Latex
KW - Natural rubber
PY - 2021
AN - OPUS4-53106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Management of Reference Data in Materials Science and Engineering Exemplified for Creep Data of a Single-Crystalline Ni-Based Superalloy
N2 - Here we present our research data management (RDM) framework to conceptualize & implement a digital infrastructure for the Generation, Distribution, and Utilization of reference datasets of materials. The documentation of the test data is often incomplete. This concerns, e.g., material’s manufacturing process or chemical composition, or test equipment’s
description and its calibration status. Our concept addresses this issue by proposing the implementation of a requirements profile. A crucial aspect of our concept is to reach a community-agreement on the definition of reference data and on the underlying data schema and vocabulary.
T2 - MaRDA2025 Virtual Annual Meeting
CY - Online meeting
DA - 18.02.2025
KW - NFDI MatWerk
KW - Referenzdaten
KW - Kriechen
KW - Datenschema
PY - 2025
AN - OPUS4-64858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Fatigue test ontology (FTO)
N2 - Fatigue Test Ontology (FTO) has developed for representing the fatigue testing process, testing equipment requirements, test pieces charactristics, and related testing parameters and their measurement procedure according to DIN EN ISO 12106 standard.
Versions info:
V2 developed using PROVO+PMDco top-level ontologies.
V3 developed using BFO+IOF top-level ontologies.
Repositories:
GitLab: https://gitlab.com/kupferdigital/process-graphs/lcf-test
GitHub: https://github.com/HosseinBeygiNasrabadi/Fatigue-Test-Ontology-FTO-
MatPortal: https://matportal.org/ontologies/FTO
IndustryPortal: https://industryportal.enit.fr/ontologies/FTO
KW - Ontology
KW - Fatigue testing
KW - FAIR data
PY - 2024
UR - https://gitlab.com/kupferdigital/process-graphs/lcf-test
UR - https://github.com/HosseinBeygiNasrabadi/Fatigue-Test-Ontology-FTO-
UR - https://matportal.org/ontologies/FTO
UR - https://industryportal.enit.fr/ontologies/FTO
PB - GitLab
CY - San Francisco, CA, USA
AN - OPUS4-60547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
A1 - Teske, Tanita
A1 - Hilgenberg, Kai
A1 - Madia, Mauro
A1 - Nielsen, S.
A1 - Gärtner, F.
A1 - Klassen, T.
T1 - Untersuchung des Potenzials von Kaltgasspritzen für die Reparatur zyklisch belasteter Bauteile
T1 - Investigation on the capability of cold-spray for repair of cyclically loaded components
N2 - Die Reparatur mittels Kaltgasspritzen ist eine vielversprechende Alternative zum
teuren Austausch fehlerbehafteter Bauteile in der Luft- und Raumfahrt. Im Rahmen
dieser Arbeit wurde das Potential des Verfahrens an der hochfesten
Aluminiumlegierungen Al6061-T6 unter Anwendung von Stickstoff als kostengünstiges
Prozessgas untersucht. Es wurden quasi-statische Zugversuche und einachsige
Zeitfestigkeitsversuche mit besonderem Fokus auf das in-situ Kugelstrahlen zur
Verbesserung der mechanischen Eigenschaften durchgeführt. Im Ergebnis wurde die
Verbesserung der Adhäsion zwischen Substrat und aufgebautem Werkstoff als
entscheidendes Kriterium für eine Anwendbarkeit ermittelt. Die Laserstrukturierung
von Substratoberflächen ist hierfür vielversprechend und wurde im Rahmen der Arbeit
mittels Adhäsionsversuchen untersucht.
N2 - Repair by cold-spray is a promising alternative to the costly replacement of flawed
components in aerospace applications. In the present work this process was
investigated on the high-strength aluminum alloy Al6061-T6. For the cold-spray
process, inexpensive Nitrogen was used as process-gas. Quasi-static tensile and highcycle-
fatigue tests (HCF) were performed, focusing on in-situ shot peening to improve
the mechanical properties of the repaired part. An improved adhesion between
substrate and built-up material was identified as a key-factor for the applicability of the
process. Under this respect laser-structuring of the substrate surface was applied and
its effect on the mechanical performance of the restored samples were examined by
adhesion tests.
T2 - 9. Tagung des DVM-Arbeitskreises Additiv gefertigte Bauteile und Strukturen
CY - Stuttgart, Germany
DA - 06.11.2024
KW - Kaltgasspritzen
KW - cold-spray
KW - Reparatur
KW - Repair
KW - Ermüdungsfestigkeit
KW - Fatigue
KW - Luft- und Raumfahrt
KW - Aerospace
KW - Substratvorbehandlung
KW - Substrate pre-treatment
PY - 2024
DO - https://doi.org/10.48447/ADD-2024-BB
VL - 409
SP - 67
EP - 79
AN - OPUS4-63182
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
A1 - Naik, Aakash
A1 - Jackson, A. J.
A1 - Baird, S.
T1 - Scripts to reproduce "Automated bonding analysis with crystal orbital Hamilton populations"
N2 - This repo allows to recreate our publication: https://doi.org/10.1002/cplu.202200123 In contrast to 0.2.2, we fixed an issue with absolute path.
KW - Automation
KW - High-throughput computations
KW - Bonding analysis
PY - 2022
UR - https://github.com/JaGeo/LobsterAutomation
UR - https://doi.org/10.5281/zenodo.6421928
UR - https://doi.org/10.5281/zenodo.6595062
UR - https://doi.org/10.5281/zenodo.6599556
UR - https://doi.org/10.5281/zenodo.6674670
UR - https://doi.org/10.5281/zenodo.6704163
DO - https://doi.org/10.5281/zenodo.6421927
PB - Zenodo
CY - Geneva
AN - OPUS4-55177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Bauer, Felix
A1 - Uhlemann, Patrick
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
T1 - KupferDigital mechanical testing datasets: Stress relaxation and low-cycle fatigue (LCF) tests
N2 - The KupferDigital project deals with the development of a data ecosystem for digital materials research on the basis of ontology-based digital representations of copper and copper alloys. This document provides exemplary mechanical testing datasets for training the developed KupferDigital infrastructures. Different types of cast copper alloys were provided for this research and their mechanical testing (stress relaxation and low-cycle fatigue) was performed in the accredited materials testing laboratory, while the test results were reported according to the DIN/ISO standards and attached with the maximum possible metadata about the sample history, equipment, and calibration. The attached content file consisted of the obtained primary raw testing data as well as the secondary datasets of these tests containing the detailed metadata of mechanical testing methods. Such test data files are processed by the KupferDigital digital tools to be converted to standardized machine-readable data files.
KW - Copper alloys
KW - Dataset
KW - Stress relaxation
KW - Mechanical testing
KW - Low-cycle fatigue.
PY - 2024
DO - https://doi.org/10.5281/zenodo.10820437
PB - Zenodo
CY - Geneva
AN - OPUS4-59665
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - BOOK
A1 - Schoch, R.
A1 - Schartel, Bernhard
A1 - Wachtendorf, Volker
A1 - Tan, Yi
A1 - Lin, Xuebao
A1 - Tröppner, O.
A1 - Lang, M.
A1 - Hochrein, T.
A1 - Bastian, M.
T1 - Langzeit- und Witterungsstabilität von halogenfreiem Flammschutz in Polymeren
N2 - Die Forderung, dass der Flammschutz von Kunststoffen nicht nur zum bei der Herstellung der jeweiligen Produkte, sondern auch über die gesamte Einsatzdauer im geforderten Maß wirksam ist, stellt eine große Aufgabe dar. Ferner ist die Anforderung für viele Produkte in der Praxis neu, da bisher vor allem der Einfluss der Flammschutzmittel auf die Stabilität der Polymerwerkstoffe, nicht aber die Stabilität des Flammschutzes untersucht wurde. Das Langzeitverhalten halogenfreier Systeme ist bis heute wenig untersucht, insbesondere weil Phosphor- und Stickstoff-basierte Systeme die oxidative Beständigkeit von Polymeren weniger zu beeinflussen scheinen als halogenhaltige FSM. Die Frage, wie zuverlässig der Flammschutz wirkt, wenn Kunststoffe einige Jahre im Innen- und Außenbereich im Einsatz sind und dabei wechselnden Beanspruchungen ausgesetzt waren, wurde bislang nur vereinzelt untersucht. Mögliche Auswirkungen von Witterungseinflüssen auf flammgeschützte Polymerwerkstoffe sind, dass die Flammschutzmittel selbst abbauen, ausgewaschen werden, oder auch durch Wechselwirkung mit den eingesetzten Additiven oder mit den Alterungsprodukten der Polymermatrix in ihrer Wirkung nachlassen. Hier bestand großer Forschungsbedarf, um an den Punkt zu gelangen, die Beständigkeit der Flammschutzeigenschaften eines Produktes über seine gesamte Lebensdauer zuverlässig garantieren zu können. Diese Fragestellung greift das durchgeführte Forschungsvorhaben auf.
Ziel war die Untersuchung der Langzeitstabilität der Flammschutzwirkung von halogenfrei flammgeschützten Polymerwerkstoffen unter diversen Witterungseinflüssen. Dazu wurden die Schädigungsmechanismen der Polymerwerkstoffe und der Flammschutzmittel sowie die auftretenden Wechselwirkungen analysiert, um ein Verständnis für die ablaufenden Prozesse zu entwickeln und Empfehlung für die Reduzierung der Alterung zu erarbeiten. Gegenstand der Untersuchungen waren anwendungsrelevante Flammschutz-Konzepte, die miteinander verglichen wurden. Die Erarbeitung von Struktur-Eigenschafts-Beziehungen ermöglichte die Beschreibung der Empfindlichkeiten und den Vergleich zwischen den Systemen. Darauf basierend wurden für die FSM spezifische Leitlinien für die Optimierung der Langzeitstabilität des Flammschutzes erstellt.
N2 - The requirement that the flame retardancy of plastics is still effective to the required degree not only at the time of manufacture of the respective products, but also over the entire period of use, is a major challenge in view of the very long periods of time involved. In addition, the requirement is new for many products in practice, as up to now the influence of flame retardants on the stability of the polymer materials has been investigated, but not the stability of the flame retardant itself. The long-term behaviour of halogen-free systems has been little studied to date, especially because phosphorus- and nitrogen-based systems seem to have a much smaller influence on the oxidative stability of polymers than halogene containing flame retardants. The question of how reliable flame retardancy is when plastic products have been in use for several years indoors and outdoors and have been exposed to a wide range of climatic stresses has only been investigated in isolated cases. Possible effects of weathering on flame-retarded polymer materials are that the flame retardants themselves degrade, migrate or are washed out, or that their effect diminishes through interaction with other additives used or with the ageing products of the polymer matrix. At this point, there was a great need for research in order to reach the point where the stability of the flame retardant properties of a product can be reliably guaranteed over its entire service life. This question is taken up by the research project carried out.
The aim of the research project was the systematic investigation of the long-term stability of the flame-retardant effect of halogen-free flame-retardant polymer materials under various weather conditions. For this purpose, the predominant damage mechanisms of the polymers and the flame retardants as well as the interactions occurring were analysed in order to develop an understanding of the processes taking place and to work out recommendations for reducing ageing. Subject of the investigations were different applicationrelevant flame retardant concepts, which were compared with each other. The development of structure-property relationships enabled the description of the specific sensitivities and the comparison between the different systems. Based on this, specific guidelines for the optimisation of the long-term stability of the flame retardants were developed for the different flame retardants.
KW - Durability
KW - Flame retardant
KW - Flammschutz
KW - Weathering
KW - Ethylene-vinyl acetate
KW - Cables
KW - Polyamid
KW - Langzeitstabilität
PY - 2021
SN - 978-3-8440-7781-0
SN - 2364-754X
SP - 1
EP - 222
PB - Shaker
CY - Düren
AN - OPUS4-54274
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Jokisch, T.
A1 - Marko, A.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Influence of electron beam welding parameters on the weld seam geometry of Inconel718 at low feed rates
N2 - Ni-based superalloys are well established in various industrial applications, because of their excellentmechanical properties and corrosion resistance at high temperatures. Despite the high development stage anda common industrial use of these alloys, hot cracking remains a major challenge limiting the weldability ofthe materials. As commonly known, the hot cracking susceptibility during welding increases with the amountof precipitation phases. Hence, a large amount of highstrength Ni-Alloys is rated as non-weldable. A newapproach based on electron beam welding at low feed rates shows great potential for reducing the hotcracking tendency of precipitation-hardened alloys. However, geometry and properties of the weld seamdiffer significantly in comparison to the common process range for practical uses. The aim of this study is toinvestigate the influence of welding parameters on the seam geometry at low feed rates between 1 mm/s and10 mm/s. For this purpose, 25 bead on plate welds on a 12 mm thick sheet made of Inconel 718 are carriedout. First, the relevant parameters are identified by performing a screening. Then the effects discovered arefurther studied by using a central composite design. The results show a significant difference between theanalyzed weld seam geometry in comparison to the well-known appearance of electron beam welded seams.
KW - Electron beam welding
KW - Ni-based superalloy
KW - Inconel 718
KW - Low feed rates
KW - Seam geometry
KW - Hot crack
PY - 2020
DO - https://doi.org/10.3139/120.111614
SN - 0025-5300
VL - 62
IS - 12
SP - 1221
EP - 1227
PB - Carl Hanser Verlag GmbH & Co. KG
CY - München
AN - OPUS4-52016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Entwicklung der Mikrostruktur der mechanischen Eigenschaften und der Eigenspannungen in L-PBF 316L
N2 - Die additive Fertigung (AM) metallischer Werkstoffe mittels Laser Powder Bed Fusion (L-PBF) ermöglicht einzigartige hierarchische Mikrostrukturen, die zu Verbesserungen bestimmter mechanischer Eigenschaften gegenüber konventionell hergestellten Varianten derselben Legierung führen können. Allerdings ist das L-PBF-Verfahren häufig durch das Vorhandensein hoher Eigenspannungen gekennzeichnet, die es zu verstehen und zu mindern gilt. Daher ist das Verständnis der Mikrostrukturen, der Eigenspannungen und der daraus resultierenden mechanischen Eigenschaften entscheidend für eine breite Akzeptanz bei sicherheitskritischen Anwendungen. Die BAM hat ein multidisziplinäres Forschungsprogramm gestartet, um diese Aspekte bei LPBF 316L zu untersuchen. Der vorliegende Beitrag stellt einige der wichtigsten Ergebnisse vor: der Einfluss von Prozessparametern auf die Mikrostruktur, der Einfluss von Mikrostruktur und Textur auf die Festigkeit, Kriechverhalten und Schädigung und die Stabilität von Eigenspannungen und Mikrostruktur unter Wärmebehandlungsbedingungen.
T2 - DGM 3. Fachtagung Werkstoffe und Additive Fertigung
CY - Dresden, Germany
DA - 11.05.2022
KW - Mechanische Eigenschaften
KW - Additive Fertigung
KW - L-PBF 316L
KW - Entwicklung
KW - Mikrostruktur
KW - Eigenspannung
PY - 2022
AN - OPUS4-55786
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Merz, Benjamin
T1 - Impact of illumination technique on the detectability of irregularities for in-situ process monitoring in PBF-LB/M
N2 - The layerwise geometry build-up of additive manufacturing (AM) enables the possibility of in-situ process monitoring. The objective is the detection of irregularities during the build cycle, ensuring component quality and process stability. Focus of this work is the visual in-situ monitoring of the process of powder bed fusion with laser beam of metals (PBF-LB/M). Current state of the art visual monitoring systems for PBF-LB/M are limited by low resolution, allowing the detection of gross flaws. In this work a 65 Mpixel high-resolution monochrome camera is integrated into a commercial PBF-LB/M machine enabling a spatial resolution of approx. 17.2 µm/Pixel. The observed inhomogeneities are clustered into directly detectable irregularities, and indirectly detectable irregularities that can be inferred from the surface. In parallel, two different illumination techniques are realized in the process chamber and compared. The impact of the distinct illumination technique, direct light and dark field, on the identification of irregularities is evaluated.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Powder bed fusion with laser beam of metals
KW - In-situ monitoring
KW - High-resolution camera
KW - Illumination technique
PY - 2024
AN - OPUS4-61094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Grandel, Jonas
A1 - George, Janine
T1 - Mace-mp-03b Phonon Benchmark
N2 - This repository contains phonon calculations and evaluations for the MACE MP-0b3 model. First release of the scripts used for the phonon benchmark in the paper benchmarking the MACE-MP-03b model. See https://arxiv.org/abs/2401.00096 for a previous version of the paper. Full Changelog: https://github.com/JaGeo/mace-mp-03b-phonon-benchmark/commits/v0.0.1
KW - Machine Learned Interatomic Potentials
KW - Phonons
KW - Thermal Conductivity
KW - Materials Searches
KW - Foundation Model
PY - 2025
DO - https://doi.org/10.5281/zenodo.15462975
PB - Zenodo
CY - Geneva
AN - OPUS4-63174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Tensile test ontology (TTO)
N2 - Tensile Test Ontology (TTO) has developed for representing the Tensile testing process, testing equipment requirements, test pieces charactristics, and related testing parameters and their measurement procedure according to DIN EN ISO 6892-1 standard.
Versions info:
V2 developed using BFO+CCO top-level ontologies.
V3 developed using PROVO+PMDco top-level ontologies.
Repositories:
GitLab: https://gitlab.com/kupferdigital/process-graphs/tensile-test
GitHub: https://github.com/HosseinBeygiNasrabadi/Tensile-Test-Ontology-TTO-
MatPortal: https://matportal.org/ontologies/TTO
IndustryPortal: https://industryportal.enit.fr/ontologies/TTO
KW - Ontology
KW - Tensile testing
PY - 2024
UR - https://gitlab.com/kupferdigital/process-graphs/tensile-test
UR - https://github.com/HosseinBeygiNasrabadi/Tensile-Test-Ontology-TTO-
UR - https://matportal.org/ontologies/TTO
UR - https://industryportal.enit.fr/ontologies/TTO
PB - GitLab
CY - San Francisco, CA, USA
AN - OPUS4-60545
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pu, Y.
A1 - Celorrio, V.
A1 - Stockmann, Jörg Manfred
A1 - Sobol, Oded
A1 - Sun, Z.
A1 - Wang, W.
A1 - Lawrence, M. J.
A1 - Radnik, Jörg
A1 - Russel, A. E.
A1 - Hodoroaba, Vasile-Dan
A1 - Huang, L.
A1 - Rodriguez, P.
T1 - Surface galvanic formation of Co-OH on Birnessite and its catalytic activity for the oxygen evolution reaction
N2 - Low-cost, high-efficient catalysts for water splitting can be potentially fulfilled by developing earthabundant metal oxides. In this work, surface galvanic formation of Co-OH on K0.45MnO2 (KMO) was achieved via the redox reaction of hydrated Co2+ with crystalline Mn4+. The synthesis method takes place at ambient temperature without using any surfactant agent or organic solvent, providing a clean, green route for the design of highly efficient catalysts. The redox reaction resulted in the formation of ultrathin Co-OH nanoflakes with high electrochemical surface area. X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the changes in the oxidation state of the bulk and
surface species on the Co-OH nanoflakes supported on the KMO. The effect of the anions, such as chloride, nitrate and sulfate, on the preparation of the catalyst was evaluated by electrochemical and spectrochemical means. XPS and Time of flight secondary ion mass spectrometry (ToF-SIMS) analysis demonstrated that the layer of CoOxHy deposited on the KMO and its electronic structure strongly depend on the anion of the precursor used during the synthesis of the catalyst. In particular, it was found that Cl- favors the formation of Co-OH, changing the rate-determining step of the reaction, which enhances the catalytic activity towards the OER, producing the most active OER catalyst in alkaline media.
KW - Nanoparticles
KW - Oxygen evolution reaction (OER)
KW - Catalysis
KW - ToF-SIMS
KW - XPS
KW - K-rich Birnessite (K0.45MnO2)
PY - 2021
DO - https://doi.org/10.1016/j.jcat.2021.02.025
VL - 396
SP - 304
EP - 314
PB - Elsevier Inc.
AN - OPUS4-52328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Damage Tolerant Approach in Additively Manufactured Metallic Materials
N2 - Damage tolerance counts as one of the most widespread approach to fatigue assessment and surely as one of the most promising in understanding the process-structure-property-performance relationships in additively manufactured metallic materials. Manufacturing defects, surface roughness, microstructural features, short and long crack fatigue propagation, residual stresses and applied loads can be taken into consideration in a fracture mechanics-based fatigue assessment. Many aspects are crucial to the reliable component life prediction. Among those a prominent role is played by an accurate measurement and modelling of the short crack fatigue behavior, and reliable statistical characterization of defects and residual stresses.
This work aims at addressing the issues related to both experimental testing, fatigue and fatigue crack propagation, and fracture mechanics-based modelling of fatigue lives. Examples will be provided on an additively manufactured AISI 316 L.
T2 - TMS2021 VIRTUAL
CY - Online meeting
DA - 15.03.2021
KW - AISI 316L
KW - Additive Manufacturing
KW - Damage Tolerance
KW - Microstructure
KW - Defects
KW - Residual Stress
PY - 2021
AN - OPUS4-52293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bergant, M.
A1 - Larrosa, N.
A1 - Yawny, A.
A1 - Madia, Mauro
T1 - Short crack growth model for the evaluation of the fatigue strength of WAAM Ti-6Al-4V alloy containing pore-type defects
N2 - The role of defects in the fatigue strength of Wire Arc Additively Manufactured (WAAMed) Ti-6Al-4V is analysed by means of the IBESS model, a fracture mechanics short crack growth approach based on the cyclic R-curve. Pores and crack-like defects are analysed. Estimations of the role of pore shape and size agree well with published fatigue data of WAAM Ti-6Al-4V with pores. The model is also used to explain the effect of fabrication defects on the scatter of experimental data. This demonstrates that short crack growth models represent a suitable engineering tool for the fatigue assessment of defective AM materials.
KW - WAAM Ti-6Al-4V
KW - Cyclic R-curve
KW - IBESS model for short cracks
KW - Kitagawa-Takahashi (K-T) diagram
PY - 2023
DO - https://doi.org/10.1016/j.engfracmech.2023.109467
SN - 0013-7944
VL - 289
SP - 1
EP - 21
PB - Elsevier Ltd.
AN - OPUS4-57963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Singh, Shobhit Pratap
A1 - Löwe, Peter
A1 - Schriever, Sina
A1 - Olbricht, Jürgen
A1 - Rehmer, Birgit
A1 - Nolze, Gert
A1 - Skrotzki, Birgit
T1 - High-throughput creep evaluation of IN738LC in bending using digital image correlation at 850 °C
N2 - High-temperature alloys, when used in structural applications, undergo slow time-dependent deformation known as creep. Assessing creep behavior is critical for estimating the in-service life of these alloys. Conventionally, uniaxial creep tests are widely conducted at elevated temperatures to determine creep rates. In recent years, bending creep of cantilevers, when combined with digital image correlation (DIC), has emerged as a promising high-throughput technique for rapidly estimating creep life. However, the applicability of bending creep above 700 ◦C for high-temperature alloys using DIC has not been fully established. In this work, we compare uniaxial creep rates of the nickel-based superalloy IN738LC with bending creep rates measured at 850 ◦C using high-temperature DIC. The bending creep data show excellent agreement with uniaxial creep results in the stress range of 240–360 MPa. The measured creep xponent, a critical rate-determining parameter, is found to be ~8 for both uniaxial and bending creep, with the rate data scattered within a factor of two. An in-house experimental setup was developed to perform bending creep tests at high temperatures, with strain monitored through DIC. Our results demonstrate that bending creep, combined with DIC, provides a reliable and efficient method for creep testing of high-temperature alloys. Compared to conventional uniaxial creep experiments, this approach requires significantly less time and material, thereby reducing effort, energy, and cost. We anticipate that this technique will serve as a foundation for testing precious high-temperature materials. For instance, in ongoing rapid discoveries of advanced alloys, in-service creep life can be evaluated much faster with reduced material requirements. Moreover, this method holds strong potential for application to high-entropy alloys and additively manufactured alloys designed for demanding high-temperature environments.
KW - Digital image correlation
KW - Bending creep
KW - Nickel-based superalloys
KW - High throughput testing
KW - High-temperature materials
PY - 2025
UR - https://www.sciencedirect.com/science/article/pii/S0921509325017034?via%3Dihub
DO - https://doi.org/10.1016/j.msea.2025.149479
VL - 950
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-64814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pourheidar, A.
A1 - Patriarca, L.
A1 - Madia, Mauro
A1 - Werner, Tiago
A1 - Beretta, S.
T1 - Progress in the measurement of the cyclic R-curve and its application to fatigue assessment
N2 - The cyclic R-curve describes the resistance of a material to fatigue crack propagation fromthe short to the long crack regimes and it is therefore an essential ingredient in any fracturemechanics-based fatigue assessment procedure. This work presents different testing proceduresemployed in the experimental determination of the cyclic R-curve, especially focusing onthe comparison with long fatigue crack propagation thresholds obtained by means of thecompression precracking load reduction (CPLR) procedure. The tests were performed on theEA4T steel considering different stress ratios. The results show a good reproducibility of thecyclic R-curves at every stress ratio and for any testing procedure. In addition, the cyclicR-curves were used in a fracture mechanics-based assessment to predict the fatigue limits ofspecimens containing micro-notches.
KW - Cyclic R-curve
KW - Fatigue limit
KW - Fatigue propagation threshold
KW - EA4T steel
KW - Digital image correlation
PY - 2022
DO - https://doi.org/10.1016/j.engfracmech.2021.108122
SN - 0013-7944
VL - 260
SP - 1
EP - 17
PB - Elsevier
CY - Kidlington
AN - OPUS4-54208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shikomba, Nikanor
A1 - Böllinghaus, Thomas
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Blasón Gonzalez, Sergio
A1 - Krafft, Eike
A1 - Staudt, Thorsten
T1 - Testing the resistance of low-alloyed steel welds for pressurized gaseous hydrogen applications
N2 - Green hydrogen has become an essential energy carrier to achieve a climate-neutral economy. The production, storage, transport and usage of green hydrogen (GH2) requires facilities and systems that are safe and sustainable. Systems for GH2 facilities, especially for storage and transport are mainly assembled of welded steel components. These components are exposed to the gaseous hydrogen environment throughout their service life. In contrast to hydrogen absorption from electrochemical environments entailing hydrogen-assisted corrosion cracking, the absorption and material degradation in gaseous environments have less been investigated. Nevertheless, the degradation of mechanical properties in materials and their welds due to absorbed hydrogen poses significant risks, including cracking and leakages. To ensure the safety and reliability of GH2 facilities throughout their service life, it is crucial to investigate and prevent such hydrogen-induced degradation, thereby avoiding potential incidental and accidental scenarios.
Due to the worldwide technology push for new energy carriers like GH2 and its derivates, extensive research and testing of welded components is not an option to avoid delays in the GH2-readiness of respective facilities. The present contribution shows how to investigate the compatibility of low alloyed steels and their welds for GH2 storage and transport subjected to quasi-static mechanical loads in principle by utilizing the Slow Strain Rate Test (SSRT) with the Hollow Specimen Technique (HST). Exemplarily, low-alloyed steel welds of the P355NL1 type currently used for hydrogen storage tanks at intermediate pressures have been investigated and compared to welds of type X65, as a very common pipeline material.
Test results show a higher value of the Hydrogen Embrittlement Index (HEI) in weld specimens than the base specimens in both investigated materials. HEI of 8.3% was recorded in base specimens and 15% in weld specimens of P355NL1, while X65 EI gives 30.2% in BM and 27.7 in WM. The fractography analysis reveals that hydrogen promotes the transition from tensile fracture to brittle fracture. Hydrogen did not show any effect on the yield strength and tensile strength of all tested specimens. However, it affects the plastic elongation of the tested materials. In conclusion, the obtained HEI values indicate a mild but significant degradation in the materials. The results confirm that hydrogen absorption from gaseous environments leads to a reduction in the mechanical properties of steels and their welds, with a more pronounced impact on ductility than on strength.
T2 - IIW Annual Assembly July 2024, Commission XI
CY - Rhodes, Greece
DA - 07.07.2024
KW - Hydrogen-assisted cracking
KW - Welded joint
KW - Hollow specimens
KW - SSRT
KW - Structural steels
PY - 2024
AN - OPUS4-61113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Multifunctional Elastomer/Graphene Nanocomposites
N2 - A few layer/multilayer graphene (MLG) with a specific surface area of BET=250 m2/g is proposed as an efficient multifunctional nanofiller for rubbers. The preparation method, i.e., ultrasonically-assisted solution mixing of master batches followed by two-roll milling, strongly influences the dispersion in the elastomeric matrix and is fundamental for the final properties. When homogenously dispersed, single stacks of only approximately 10 graphene sheets, with an aspect ratio of 34, work at low loadings, enabling the replacement of large amounts of carbon black (CB), an increase in efficiency, and a reduction in filler load. The appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing, gas barrier properties, electrical and thermal conductivity, as well as mechanical properties of different rubbers, as shown for chlorine-Isobutylene-Isoprene rubber (CIIR), nitrile-butadiene rubber (NBR), natural rubber (NR), and styrene-butadiene rubber (SBR). 3 phr of MLG tripled the Young’s modulus of CIIR, an effect equivalent to 20 phr of CB. The stronger interactions between MLG and NR or SBR also resulted in a reduction in the elongation at break by 20% and 50%, respectively, while the same parameter was hardly changed for CIIR/MLG and NBR/MLG. CIIR/MLG and NBR/MLG were stiffer but just as defomable than CIIR and NBR. The strong reinforcing effect of 3 phr MLG was confirmed by the increase of greater than 10 Shore A in hardness. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards flammability, the latter shown by the reduction in heat release rate in the cone calorimeter. We investigated MLG also as a synergist for reducing the aluminium trihydrate loading in flame retardant hydrogenated acrylonitrile-butadiene (HNBR), polybutadiene chloroprene (BR/CR), and chlorosulfonated polyethylene rubber(CSM). The higher the nanofiller concentration is, the greater the improvement in the properties. For instance, the permeability decreased by 30% at 3 phr of MLG, 50% at 5 phr and 60% at 10 phr, respectively. Moreover, the MLG nanocomposites improve stability of mechanical properties against the effects of weathering. In key experiments an increase in UV-absorption and a pronounced radical scavenging were proved as stabilizing mechanisms. In a nutshell, MLG is an efficient multifunctional nanofiller ready to be used for innovative rubber development.
T2 - 19th European Polymer Congress, EPF 2022
CY - Prague, Czech Republic
DA - 26.06.2022
KW - Graphene
KW - Nanocomposite
KW - Rubber
KW - Elastomer
PY - 2022
AN - OPUS4-55196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Ansätze zur digitalen Wissensrepräsentation aus der Plattform MaterialDigital (PMD)
N2 - Die Digitalisierung von Materialien und Prozessen stellt eine große Herausforderung dar, die nur durch eine Bündelung der Bemühungen aller Beteiligten in diesem Bereich erreicht werden kann. Bei einer derartigen digitalen Beschreibung spielen Datenanalysemethoden, eine Qualitätssicherung von Prozessen inklusive Input- und Output-Daten sowie die Interoperabilität zwischen Anwendungen nach den FAIR-Prinzipien eine wichtige Rolle. Dies umfasst das Speichern, Verarbeiten und Abfragen von Daten in einer vorzugsweise standardisierten Form (Beteiligung von Normungsgremien).
Zur Bewältigung dieser Herausforderung ist eine mit allen Stakeholdern konsistente Kontextualisierung der Materialdaten anzustreben, d.h. alle erforderlichen Informationen über den Zustand des Materials einschließlich produktions- und anwendungsbezogener Änderungen müssen über eine einheitliche, maschinenlesbare Beschreibung verfügbar gemacht werden. Dazu werden Wissensrepräsentationen und Konzeptualisierungen ermöglichende Ontologien verwendet. Eine zentrale Betrachtungsweise in diesem Zusammenhang ist die Realisierung von (automatisierten) Datenpipelines, die eine Beschreibung und Verfolgung von Daten ausgehend von ihrer Erzeugung, bspw. in einem Messgerät, bis zu ihrer globalen Verwendung in möglicherweise verschiedenen Kontexten beinhalten.
Erste Bemühungen und Ansätze zu diesen Problemstellungen führten im Projekt Innovations-Plattform Material Digital (PMD, materialdigital.de) zur Erstellung von Anwendungsontologien, die Prozesse und Testmethoden explizit beschreiben. Dabei wurde u.a. der Zugversuch an Metallen bei Raumtemperatur nach ISO 6892-1 ontologisch beschrieben. Diese als Beispiel dienende Ontologieentwicklung wird in dieser Präsentation vorgestellt. Weiterhin wurde, ausgehend von der domänenspezifischen Entwicklung von Anwendungsontologien, eine Kernontologie erstellt, die eine übergeordnete Verbindung von ontologischen Konzepten aufgrund der Verwendung gleichen Vokabulars und semantischer Verknüpfungen erlaubt. Diese sowie die das PMD-Projekt selbst werden ebenfalls in dieser Präsentation vorgestellt.
T2 - DVM Workshop: Grundlagen und Beispiele zur Digitalisierung für die Materialforschung und -prüfung
CY - Online meeting
DA - 19.10.2021
KW - Plattform Material Digital (PMD)
KW - Ontologie
KW - Zugversuch
KW - Wissensrepräsentation
KW - Semantic Web
PY - 2021
AN - OPUS4-53565
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bergant, M.
A1 - Werner, Tiago
A1 - Madia, Mauro
A1 - Yawny, A.
A1 - Zerbst, Uwe
T1 - Short crack propagation analysis and fatigue strength assessment of additively manufactured materials: An application to AISI 316L
N2 - This paper presents the application of short crack propagation models based on the cyclic R-curve for assessing the fatigue strength of additively manufactured (AM) materials containing fabrication defects. Chapetti’s and IBESS models were implemented in combination with Murakami’s √area parameter, considering recently published data on laser powder bed fusion processed AISI 316L stainless steels. Estimated S-N curves and Kitagawa-Takahashi diagrams predict fairly well the experimental data, especially the origin of the failure from internal or surface defects. These results provide an indication that the methods based on the cyclic R-curve constitute suitable tools for fatigue behavior assessment of AM materials.
KW - AM 316L stainless steel
KW - Cyclic R-curve
KW - Chapetti’s and IBESS model
KW - S-N curve
KW - Kitagawa-Takahashi diagram
PY - 2021
DO - https://doi.org/10.1016/j.ijfatigue.2021.106396
VL - 151
PB - Elsevier Ltd.
AN - OPUS4-53082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuschner, Nils
A1 - Altenburg, Simon
A1 - Pignatelli, Giuseppe
A1 - Maierhofer, Christiane
A1 - Straße, Anne
A1 - Gornushkin, Igor B.
A1 - Gumenyuk, Andrey
T1 - Vergleich der Messungen der Schmelzbadtemperatur bei der Additiven Fertigung von Metallen mittels IR-Spektroskopie und Thermografie
T1 - Comparison of measurements of the melt pool temperature during the additive production of metals by means of IR spectroscopy and thermography
N2 - Im Rahmen des Themenfeldprojektes „Process Monitoring of AM“ (ProMoAM) evaluiert die Bundesanstalt für Materialforschung und -Prüfung (BAM) gegenwärtig die Anwendbarkeit verschiedenster ZfP-Verfahren zur in-situ Prozessüberwachung in der additiven Fertigung (AM) von Metallen in Hinblick auf die Qualitätssicherung.
Einige der wichtigsten Messgrößen sind hierbei die Temperatur des Schmelzbades und die Abkühlrate, welche starken Einfluss auf das Gefüge und die Eigenspannung haben. Aufgrund der Zugänglichkeit zum Werkstück während des Bauprozesses bieten sich optische Verfahren zu Temperaturbestimmung an. Hierbei stellen jedoch u. a. die hohe Bandbreite der zu messenden Temperaturen, die Bestimmung der Emissivität und ihre Änderung bei Phasenübergängen der verwendeten Legierung große experimentelle Herausforderungen dar. Eine weitere Herausforderung stellt für die IR-Spektroskopie die Absorption durch das Schutzgas und weitere optische Elemente dar. Um diese auch in einem industriellen Umfeld kompensieren zu können, wurde eine Methode entwickelt, die das gemessene Spektrum bei der Verfestigung des Werkstoffes als Referenz nutzt. In diesem Beitrag wird die Anwendung dieser Methode für die IR-Spektrometrie als auch Thermografische Messungen beim Laser-Pulver-Auftragschweißen von 316L gezeigt, wobei beide Methoden weiterhin in Hinblick auf ihre individuellen Vor- und
Nachteile miteinander verglichen werden.
N2 - Within the topic area project “Process Monitoring of AM” (ProMoAM) the Federal Institute for Materials Research and Testing is currently evaluating the applicability of various NDT methods for in-situ process Monitoring in the additive manufacturing (AM) of metals with regard to quality assurance. Two of the most important variables to measure are the temperature of the molten pool and the cooling rate, which have a strong influence on the microstructure and the residual stress. Due to the accessibility of the workpiece during the construction process, optical methods for temperature determination are suitable.
However, the wide range of temperatures to be measured, the determination of emissivity and its change during phase transitions of the alloy pose great experimental challenges. Another challenge for IR spectroscopy is the absorption by the inert gas and other optical elements. In order to be able to compensate for this in an industrial environment, a method was developed which uses the measured spectrum as a reference when the material is solidified.
This paper shows the application of this method for IR spectrometry as well as thermographic measurements during laser powder cladding of 316L. Furthermore both methods are compared with respect to their individual Advantages and disadvantages.
KW - Laser-Pulver-Auftragschweißen
KW - Thermografie
KW - Direct Energy Deposition
KW - IR-Spektroskopie
KW - Additive Fertigung
KW - Laser metal deposition
KW - Thermography
KW - IR-spectroscopy
KW - Additive manufacturing
PY - 2021
DO - https://doi.org/10.1515/teme-2021-0056
VL - 88
IS - 10
SP - 626
EP - 632
PB - De Gruyter
CY - Oldenburg
AN - OPUS4-52987
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Kiyak, Yusuf
A1 - Breidung, Marc
A1 - Baer, Wolfram
A1 - Küppers, M.
ED - Madia, Mauro
T1 - Stiffness/constraint effects in analytical flaw assessment - A technical note
N2 - Using the case study of a fail-safe design criterion for a steering knuckle of a commercial vehicle, the effect of stiffness/constraint on the crack driving force in the component is discussed. The problem arises when assessment procedures such as R6, BS 7910 or SINTAP/FITNET are applied in conjunction with substitute geometries for determining the model parameters K-factor and limit load (or a substitute for the latter), as it is common practice. In the example, the conservatism was so pronounced that this procedure was in fact unusable. A way out could be the finite element-based determination of the model parameters and their use in the analytical framework. This procedure is useful and effective if the finite element-based calculations are used in parameter sensitivity analyses.
KW - Fail-safe design
KW - Fracture resistance
KW - Fracture assessment
KW - Stiffness
KW - Constraint
PY - 2022
DO - https://doi.org/10.1016/j.engfracmech.2022.108728
SN - 0013-7944
IS - 273
SP - 1
EP - 15
PB - Elsevier Science
CY - Kidlington
AN - OPUS4-55544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baer, Wolfram
A1 - Breidung, Marc
A1 - Kiyak, Yusuf
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Küppers, M.
T1 - Aspekte der analytischen bruchmechanischen Bauteilbewertung
N2 - Am Beispiel eines abgesetzten zylindrischen Bauteils (Achsschenkel) werden Probleme der analytischen bruchmechanischen Bauteilbewertung diskutiert. Als Basis-philosophie wird ein Fail Safe-Kriterium (kontrolliertes Versagen) angesetzt. Die Forderung ist, dass sich der Achsschenkel, bevor er bricht, in einem Ausmaß plastisch verformen kann, bei dem der Fahrer bemerkt, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Um das zu gewährleisten, muss der Werkstoff einen bestimmten Riss-widerstand aufweisen. Dazu werden im hier vorgestellten ersten Teil des Projektes mittels FEM Rissspitzenbeanspruchungen in Abhängigkeit von der Auslenkung des Zylinders und angenommener Rissgrößen ermittelt. Diese finden als Zielgrößen in der weiteren Analyse Anwendung. Da eine einfach umzusetzende Lösung angestrebt wird, werden zusätzlich analytische Rechnungen an Ersatzgeometrien (halbunendliche Platte und Vollzylinder), aber mit den realen Spannungen am Bauteil durchgeführt. Es zeigt sich, dass die Ergebnisse wegen des Steifigkeitsunterschieds zwischen Bauteil und Ersatzgeometrie unvertretbar konservativ sind. Alternativ wird ein hybrides Konzept vorgestellt, für das die Modellparameter mittels FEM bestimmt werden. Es liefert sehr genaue Ergebnisse. Im Rahmen der analytischen Rechenvorschrift können die Lösungen auf andere Werkstoffe übertragen werden, ohne dass zusätzliche FEM-Analysen notwendig sind.
T2 - 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 22.02.2022
KW - FEM
KW - Bauteilbewertung
KW - Fail-safe
KW - Analytisches Modell
PY - 2022
DO - https://doi.org/10.48447/Br-2022-BB
VL - 254
SP - 1
EP - 11
PB - DVM
CY - Berlin
AN - OPUS4-54406
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Kurzrisswachstum in additiv gefertigtem austenitischem Edelstahl 316L
N2 - Diese Untersuchung beschäftigt sich mit der Charakterisierung von Kurzrisswachstum in mittels Laser-Pulverbett-Verschmelzen (LPBF - Laser Powder Bed Fusion) hergestelltem rostfreien austenitischen Stahl. Spezifischer wird die Ermittlung zyklischer R-Kurven untersucht. Diese beschreiben den Aufbau des Widerstands gegen Ermüdungsrisswachstum - d.h. des Schwellenwertes - aufgrund von Rissschließeffekten bei physikalisch kurzen Rissen. Mit Hilfe der zyklischen R-Kurven kann die Fähigkeit eines Bauteils, physikalisch kurze Risse zu arretieren, charakterisiert werden. Wir verfügen damit über eine Schnittstelle zwischen klassischer Ermüdung und Bruchmechanik. Das ist gerade auch für additiv gefertigte (AM – Additive Manufacturing) Materialien von Interesse. Diese weisen prozessintrinsische Defekte auf, die als Initiierungsstellen kurzer Ermüdungsrisse agieren. Im Rahmen der experimentellen Untersuchungen wurden zyklische R-Kurven für konventionellen und LPBF AISI-316L-Stahl ermittelt. Insbesondere wurde der Einfluss verschiedener Wärmebehandlungen (WB1: 450°C, WB2: 800°C und WB3: 900°C) auf das Wachstumsverhalten physikalisch kurzer Risse im LPBF-Material untersucht. Aufgrund hoher Eigenspannungen war die Ermittlung des Kurzrisswachstumsverhaltens bei WB1 nicht möglich. Für WB2 und WB3 ergaben sich sehr unterschiedliche zyklische R-Kurven. Untersuchungen der Eigenspannungen, der Bruchfläche (insbesondere der Rauheit) und der Mikrostruktur sollen die Ursachen für das unterschiedliche Verhalten erklären. Die Ergebnisse werden mit den Verhältnissen in konventionellem Material verglichen.
T2 - 41. Werkstoffmechanikseminar TU Darmstadt
CY - Online meeting
DA - 26.10.2020
KW - AM
KW - Additiv
KW - Zyklische R-Kurve
KW - 316L
KW - Ermüdung
KW - Ermüdungsrisswachstum
KW - Risswachstum
PY - 2020
AN - OPUS4-51603
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chen, Yue
T1 - Ontopanel: a diagrams.net plugin for graphical semantic modelling
N2 - Ontologies that represent a map of the concepts and relationships between them, are becoming an effective solution for data standardization and integration of different resources in the field of materials science, as efficient data storage and management is the building block of material digitization. However, building a domain ontology is not a simple task. It requires not only a collaborative effort between ontologists and domain experts, but also the modeling approaches and tools play a key role in the process. Among all approaches, graphical representation of domain ontologies based on standard conceptual modeling languages is widely used because of its intuitiveness and simplicity. Various tools have been developed to realize this approach in an intuitive way, such as Protégé plugins and web visualization tools.
The Materials-open-Lab (MatOLab) project, which aims to develop ontologies and workflows in accordance with testing standards for the materials science and engineering domains, adopted a UML (Unified Modeling Language) approach based on the diagrams.net. It is a powerful, popular, open-source graphical editor. In practical case studies, however, many users’ needs could not be met, such as reusing ontology, conversion, and data mapping. Users must switch between different tools to achieve a certain step, and thereby invariably increase learning cost. The lack of validation also leads to incorrect diagrams and results for users who are not familiar with the ontology rules. To address these issues, we designed Ontopanel, a diagrams.net-based plugin that includes a set of pipeline tools for semantic modeling: importing and displaying protégé-like ontologies, converting diagrams to OWL, validating diagrams by OWL rules, and mapping data. It uses diagrams.net as the front-end for method modeling and Django as the back-end for data processing. As a web-based tool, it is very easy to expand its functionality to meet changing practical needs.
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Ontology
KW - Tools
KW - Material digital
KW - Mat-o-lab
KW - Graphic design
KW - Ontology development
KW - Data mapping
KW - FAIR
KW - Materials testing
PY - 2022
AN - OPUS4-55884
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Ermittlung des intrinsischen Schwellenwerts und dessen Validierung als Werkstoffparameter
N2 - Die schadenstolerante Bewertung von zyklisch beanspruchten Bauteilen auf bruchmechanischer Grundlage ist von großer praktischer Bedeutung, insbesondere für die Spezifizierung von Inspektionsintervallen. Eine Schwachstelle der gegenwärtigen Vorgehensweise bildet der nur ungenügend verstandene Schwellenwertbereich der da/dN-ΔK -Kurve. Relevant ist das deshalb, weil viele Bauteile bei Lasten betrieben werden, die in eben diesen Bereich fallen. Der Vortrag beschäftigt sich mit Unsicherheiten bei der Ermittlung des Schwellenwertes, mit Einflussparametern, die dabei zu berücksichtigen sind, und mit einem Vorschlag zur konservativen Einbeziehung des Schwellenwertbereichs
in die Bauteilauslegung.
Der Schwellenwert gegen Ermüdungsrissausbreitung ist als der zyklische Spannungsintensitätsfaktor definiert, unterhalb dessen kein Risswachstum mehr stattfindet. Dabei ist zu beachten, dass der Wert in der konventionellen da/dN-ΔK -Kurve auf Langrisswachstum beschränkt ist und, strenggenommen, auch das nur dann, wenn das Rissschließphänomen voll ausgebildet ist. Unter Rissschließen versteht man das Schließen des zyklisch beanspruchten Risses in der Regel oberhalb des Nulldurchgangs der Last. Wichtige Rissschließmechanismen sind das plastizitäts-, das rauheits- und das oxid-induzierte Schließen wobei die beiden letztgenannten im Schwellenwertbereich dominierend sind. Der Schwellenwert selbst besteht aus zwei Anteilen, einem intrinsischen, der von den elastischen Konstanten und vom Gittertyp abhängt und einem extrinsischen, der mit dem Aufbau der Rissschließeffekte zusammenhängt und von Parametern wie der Mikrostruktur, dem Spannungsverhältnis aus Unter- und Oberlast und der Risstiefe beeinflusst wird.
In Fällen, bei denen oxid-induziertes Rissschließen eine Rolle spielt, hängt der erhaltene Wert des Schwellenwerts vom experimentellen Verfahren ab, wobei die konventionelle Lastabsenkung nach Standard nicht-konservative Werte ergeben kann. Der Vortrag thematisiert die unterschiedlichen Optionen der experimentellen Ermittlung mit besonderem Fokus auf dem intrinsischen Schwellenwert und, davon ausgehend, die Anbindung an den rissschließkorrigierten Paris-Bereich der da/dN-ΔK -Kurve.
T2 - Werkstoffmechanikseminar 2020
CY - Online meeting
DA - 26.10.2020
KW - Intrinsischer Schwellenwert gegen Ermüdungsrissausbreitung
KW - Schadenstolerante Bauteilauslegung
KW - Restlebensdauer
PY - 2020
AN - OPUS4-51604
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Jonathan
T1 - Hochaufgelöste visuelle In-situ Prozessüberwachung im PBF-LB/M
N2 - Im Rahmen dieses Vortrags werden die bisherigen Arbeiten des Fachbereichs 9.6 zur hochauflösenden visuellen In-Situ Prozessüberwachung im pulverbettbasierten Schmelzen von Metall mittels Laserstrahl (PBF-LB/M) vorgestellt. Als Kamerasystem dient eine 65-Megapixel-Monochromkamera, die in eine kommerzielle PBF-LB/M-Maschine integriert wurde und eine räumliche Auflösung von 17,2 µm/Pixel erreicht. Zur Problemstrukturierung werden Defekte im PBF-LB/M als indirekte und direkte Defekte klassifiziert und ihre Erkennung anhand von Schichtbildern diskutiert. Zudem wird der Einfluss der Beleuchtungssituation auf die Erkennbarkeit von Defekten untersucht. Darüber hinaus wird der Kontrast der Grauwertmatrix als Indikator für das Vorliegen von Bindefehlern vorgestellt.
T2 - 11. Mitteldeutsches Forum 3D-Druck in der Anwendung
CY - Merseburg, Germany
DA - 16.10.2024
KW - Additive manufacturing
KW - Image processing
KW - In-situ monitoring
PY - 2024
AN - OPUS4-61376
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dittmann, Daniel
T1 - Aktivkohlecharakterisierung von GAK-Filtern bei unterschiedlichen Laufzeiten
N2 - Eine umfangreich ausgestaltete Trinkwasseraufbereitung als Multibarrieren-System ist notwendig, wenn das Rohwasser direkt aus Fließgewässern entnommen wird (z. B. für das Mülheimer Verfahren). Eine der Barrieren wird, als gezielte Behandlungs- oder Sicherheitsstufe, oft als Filter mit granulierter Aktivkohle (GAK-Filter) realisiert. Ihre Standzeit kann bei geringer Wasserbelastung (DOC < 2 mg/L), z. B. bei der Landeswasserversorgung Langenau, bis zu 5 Jahre betragen. Bei Rohwasser mit höherem Organikgehalt (DOC > 7 mg/L), wie bei der Nordwasser in Rostock, wird hingegen mindestens alle drei Jahre die GAK in den Filterkolonnen ausgetauscht.
Die Rest-Adsorptionskapazität der GAK kann durch verschiedene Verfahren abgeschätzt werden, ist aber nach wie vor Gegenstand aktueller Forschung. Die weitergehende Charakterisierung der beladenen GAK kann hierbei helfen.
Auf dem Poster sollen erste Ergebnisse zu den in Langenau und Rostock eingesetzten Aktivkohlen präsentiert werden. Hierzu wurden die frischen und nach unterschiedlichen Laufzeiten beladenen GAK untersucht. Die Zusammensetzung der Anorganik und der adsorbierten Organik, welche mittels Zersetzungs¬gasanalyse charakterisiert wurde, zeigt deutliche Unterschiede. Bspw. nimmt der Calcium-Gehalt der GAK in Langenau kontinuierlich zu, wohingegen dieser in den Proben aus Rostock mit zunehmender Laufzeit zurückgeht. Umgekehrt verhält es sich mit der Organik: Die GAK aus Rostock zeigen Hinweise auf biologische Besiedelung, während diese in Langenau trotz längerer Filterlaufzeit auszubleiben scheint.
T2 - 4. Mülheimer Wasseranalytisches Seminar (MWAS2020)
CY - Mülheim an der Ruhr, Germany
DA - 16.09.2020
KW - Thermogravimetrie
KW - Trinkwasser
KW - Wasseraufbereitung
KW - Aktivkohle
PY - 2020
AN - OPUS4-51433
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Creep Behavior of Stainless Steel 316L Manufactured by Laser Powder Bed Fusion
N2 - Metal additive manufacturing (Metal AM) continues to gain momentum. Many companies explore the manufacturing of innovative products, including components for safety critical applications. Despite the intensive research of recent years, a fundamental understanding of the process‑structure‑property relationships remains challenging due to, i.a., the inherently complex and highly hierarchical microstructures arising from the wide range of build process parameter variability. This contribution presents the resu lts of an experimental study on the creep behavior of an austenitic 316L stainless steel produced by laser powder bed fusion (PBF LB/M/316L) with an emphasis on understanding the effects of microstructure on creep mechanisms. Hot tensile tests and constant force creep tests at 600 °C and 650 °C, X ray computed tomography, as well as optical and electron microscopy were performed. The produced PBF LB/M/316L exhibits a low void population 0.01 %) resulting from the manufacturing parameters used and which a llowed us to understand the effects of other microstructural aspects on creep behavior, e.g., grain morphology and dislocation substructure. A hot‑rolled variant of 316L hwas also tested as a reference. The produced PBF LB/M/316L possesses shorter primary and secondary creep stages and times to rupture and smaller creep stress exponents than the hot‑rolled variant. Overall, the creep damage is more extensive in the PBF LB/M/316L and is characterized as predominantly intergranular. It is considered that the damage behavior is mainly impacted by the formation of precipitates at the grain boundaries combined with their unfavorable orientation. The dislocation substructure and local elemental segregation appear to have a decisive impact on the overall creep behavior.
T2 - 16th International Conference on Creep and Fracture of Engineering Materials and Structures
CY - Bangalore, India
DA - 28.07.2024
KW - AGIL
KW - 316L
KW - Additive Manufacturing
KW - Creep
KW - Microstructure evolution
PY - 2024
AN - OPUS4-60839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
A1 - George, Janine
A1 - Mieller, Björn
A1 - Stawski, Tomasz
T1 - ZrV2O7 negative thermal expansion (NTE) material
N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material that exhibits significant isotropic contraction over a broad temperature range (~150°C < T < 800°C). Therefore, it can be used to create composites with controllable expansion coefficients and prevent thermal stress, fatigue, cracking, and deformation at interfaces. We implement interdisciplinary research to analyze such material. We study the influence of the synthesis methods and their parameters on the sample's purity, crystallinity, and homogeneity. Moreover, we implement ab initio-based vibrational computations with partially treated anharmonicity in combination with experimental methods to follow temperature-induced structural changes and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder.
T2 - SALSA Make and Measure Conference
CY - Berlin, Germany
DA - 13.09.2023
KW - NTE
KW - Composites
KW - TEM
PY - 2023
AN - OPUS4-58367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Skrotzki, Birgit
A1 - Czichos, Horst
ED - Hennecke, Manfred
ED - Skrotzki, Birgit
T1 - Die Werkstoffklassen
N2 - Es werden die vier Werkstoffklassen Metalle, Keramiken, Polymere und Verbundwerkstoffe sowie ihre Untergruppen vorgestellt. Die metallischen Werkstoffe umfassen die Eisen- wie die Nichteisenwerkstoffe und ihre Legierungen. Neben den Ingenieurkeramiken werden auch Glas und Glaskeramik, Naturstoffe und Erdstoffe sowie Baustoffe behandelt.
KW - Metall
KW - Keramik
KW - Glas
KW - Polymer
KW - Verbundwerkstoff
PY - 2020
SN - 978-3-662-57492-8
DO - https://doi.org/10.1007/978-3-662-57492-8_28-1
SP - 1
EP - 35
PB - Springer-Verlag GmbH Deutschland
CY - Berlin, Heidelberg
ET - 35.
AN - OPUS4-50297
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Camin, B.
T1 - Grenzflächenanalyse diffusionsgeschweißter Werkstoffpaarungen Nickel/ Nickelbasis-Superlegierung CMSX-4
N2 - Der Kirkendall-Effekt tritt bei aneinandergrenzenden Metallpaarungen auf, die höheren Temperaturen ausgesetzt sind. Es findet als Funktion von der Temperatur, der Zeit und der Konzentration die Diffusion von Atomen und Leerstellen über die Phasengrenze hinweg statt. Für die Untersuchung des Kirkendall-Effekts wurde mittels Diffusionsschweißens eine Werkstoffpaarung bestehend aus reinem Nickel (Ni) und der Nickelbasis-Superlegierung CMSX-4 hergestellt. Das Gefüge des reinen Nickels ist polykristallin und von CMSX-4 einkristallin. Da der Kirkendall-Effekt neben den oben genannten Parametern zudem von der Kristallorientierung abhängig ist, wurden zwei verschiedene Kristallorientierungen, die [111]- und [001]-Richtungen, gewählt. Aus 3D µ-tomografischen Untersuchungen ist bekannt, dass heiß-isostatisches Pressen (HIP) eine Verringerung der Porosität in CMSX-4 bewirkt, die durch die Erstarrung des Einkristalls bei der Herstellung entsteht [1]. Daher wurden bei den Diffusionsschweißungen Werkstoffpaarungen von reinem Nickel mit drei CMSX-4-Varianten -mit einer γ/γ‘-Mikrostrukturkombiniert: Ni/ CMSX-4 [111], Ni/ CMSX-4 [001] und Ni/ CMSX-4 [001]-HIPed. Die bei der Diffusionsschweißung entstehenden Grenzschichten wurden mittels Stereo-, Licht- und
Rasterelektronenmikroskopie sowie EDX-Analysen untersucht. Bei allen Diffusionsschweißungen entstand eine feste Verbindung zwischen den Werkstoffpaarungen. Wie bereits aus [2] bekannt, bildet sich bei allen Proben auf der Rein-Nickelseite der Grenzfläche ein Porensaum aus, während sich auf der CMSX-4-Seite ein γ‘-freie Zone bildet (Abbildung 1). Sowohl die jeweilige Porosität als auch Porengröße des Porensaums der drei Werkstoffpaarungen ist verschieden. Dieses gilt ebenso für die durchschnittliche Schichtdicke der γ‘-freie Zone. Die geringste durchschnittliche Schichtdicke mit 1,45 µm weist die Paarung Ni/ CMSX-4 [001]-HIPed (Abbildung 1b) auf, wobei die Dicke über den
Probenquerschnitt konstant ist. Dagegen schwanken die Schichtdicken der γ‘-freie Zonen bei Ni/ CMSX� 4 [111] (Abbildung 1c) zwischen 1,82 – 4,1 µm und Ni/ CMSX-4 [001] (Abbildung 1a) zwischen 1,36 - 4,55 µm.
EDX-Messungen (Linescans) von der CMSX-4-Seite über die γ‘-freie Zone bis in den Nickelwerkstoff zeigen den qualitativen Verlauf der Elementkonzentrationen von Nickel und Aluminium (Abbildung 2). Bei allen Werkstoffpaarungen nimmt die Konzentration des Elements Nickel kontinuierlich zu. Während in der Werkstoffpaarung Ni/CMSX-4 [111] der Konzentrationszunahme symmetrisch über die
Grenzfläche verläuft, weist Nickel bei den Werkstoffpaarungen Ni/CMSX-4 mit [001]-Orientierung keinen symmetrischer Konzentrationsverlauf auf. Daraus lässt sich schließen, dass hier die Diffusion von Nickel über die Grenzfläche in die γ‘-freie Zone in Abhängigkeit von der Kristallorientierung unterschiedlich stattfindet.
Entgegengesetzt diffundiert das Element Aluminium von der CMSX-4-Seite zur Nickelseite, wie sich aus dem ebenfalls unsymmetrischen Elementverlauf schließen lässt. Bemerkenswert ist hier ein Knick, der sich nach einem Steilabfall einem Plateau anschließt, wie im vergrößerten Ausschnitt in Abbildung 2 mit einem roten Pfeil markiert ist. Dieser Verlauf ist von der Kristallorientierung unabhängig und ist auf die bessere Diffusivität von Al im Vergleich zu Ni zurückzuführen.
T2 - Materialographie 2024
CY - Berlin, Germany
DA - 18.09.2024
KW - Diffusionsschweißen
KW - Grenzfläche
KW - Nickelbasis-Superlegierung
KW - Kirkendall-Effekt
PY - 2024
AN - OPUS4-61095
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Han, Ying
T1 - Segmented primary phases of Al-alloy EN AW-2618A in the T61 state using synchrotron computed tomography
N2 - The video file contains data from a synchrotron computed tomography measurement of the primary phases of the Al-alloy EN AW-2618A in the T61 state. The volume fraction of the primary phases was determined.
KW - Aluminum alloy
KW - EN AW-2618A
KW - Computed tomography
KW - Primary phases
PY - 2024
DO - https://doi.org/10.5281/zenodo.12730717
PB - Zenodo
CY - Geneva
AN - OPUS4-60657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gesell, Stephan
T1 - A CTOD-based crack growth law for thermomechanical fatigue
N2 - Due to combined cyclic mechanical and thermal loading during operation, the material of exhaust gas conducting components of combustion engines is exposed to thermomechanical fatigue (TMF). This leads to formation and growth of cracks, especially at the most highly stressed points of these components. In order to better predict the service life of cracked components before failure, it is necessary to identify a crack propagation law for the material used. Isothermal crack propagation tests have been carried out at several temperatures with a typical cast iron to identify such a law. The crack length is measured by the potential drop method. The compliance method, fractography and thermographic camera measurements have been used to validate and calibrate the potential drop measurements. Each of the isothermal tests has been simulated using a specially developed FEM-algorithm based on remeshing and remapping. This algorithm has been implemented in python and ABAQUS. Thereby, the crack tip region is modeled by collapsed Quad8 elements. From the individual simulations, the cyclic crack tip opening displacement (ΔCTOD) is extracted and regarded as a potential fracture mechanics parameter which controls the crack growth rate. By combining the data from the experiments and the simulations, the crack propagation law has been identified. Finally, anisothermal crack propagation tests have been performed for validation of the crack growth law.
T2 - European Conference on Fracture 2022
CY - Funchal, Portugal
DA - 27.06.2022
KW - Fatigue crack growth
KW - Finite elmenet simulation
KW - TMF experiments
PY - 2022
AN - OPUS4-56934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Anwendung von repräsentativen Proben zur Bewertung der Strukturintegrität von sicherheitsrelevanten Komponenten
N2 - Sicherheitsrelevante Bauteile, bei denen ein Versagen im Betrieb katastrophale Folgen haben könnte, sind in der Regel für eine sehr geringe Ausfallwahrscheinlichkeit ausgelegt und unterliegen strengen Qualifizierungsverfahren gemäß den von den Aufsichtsbehörden festgelegten Richtlinien. Die Hersteller sind oft gezwungen, Tests an realen oder skalierten Komponenten durchzuführen, um die Strukturintegrität unter definierten Belastungsbedingungen sicherzustellen, die in der Regel strenger sind als die im Betrieb zu erwartenden. Dies ist in der Regel mit einem enormen experimentellen und finanziellen Aufwand verbunden. Daher versuchen die Unternehmen, neue Strategien wie digitale Zwillinge zu entwickeln, mit denen die Kosten massiv gesenkt werden können, ohne die Sicherheit zu beeinträchtigen. In dieser Arbeit wird ein neues quasistatisches Prüf- und Bewertungskonzept vorgestellt, dessen Hauptidee darin besteht, die experimentelle Prüfung von Bauteilen durch die Prüfung von für das Bauteil repräsentativen Proben zu ersetzen oder zumindest zu reduzieren. Der größte Vorteil des vorgeschlagenen Konzepts besteht darin, dass die Versuche auf Laborprüfmaschinen durchgeführt werden können. Die Wirksamkeit der Methodik wird anhand der Bewertung der Strukturintegrität einer Turbinenscheibe aus einer Ni-Basis-Superlegierung für Flugzeugtriebwerke bei Überdrehzahl demonstriert.
T2 - 57. Tagung des Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Cologne, Germany
DA - 18.02.2025
KW - Strukturintegrität
KW - Bruchmechanik
KW - Turbinenscheibe
KW - Repräsentative Proben
PY - 2025
AN - OPUS4-62601
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Szymoniak, Paulina
T1 - Bio-Based Vitrimers: Cracking the Code of Recyclability, Exchange Reactions and Flame Retardancy
N2 - Vitrimers are a promising class of sustainable materials that offer an alternative to traditional epoxy thermosets in line with circular economy principles. Built on covalent adaptive networks (CANs), they can rearrange their chemical bonds in response to external stimuli, giving them properties like recyclability, shape-memory, and self-healing. These materials combine the strength of thermosets with the reprocessability of thermoplastics, making them attractive for next-generation applications.
This study focuses on a bio-based vitrimer made from glycerol triglycidyl ether (GTE) and a vanillin-derived imine hardener (VA), which reacts through catalyst-free imine metathesis. To better understand the recyclability mechanisms of such systems, especially the dynamic bond exchange, we apply a comprehensive suite of techniques including dielectric spectroscopy, neutron scattering, mechanical analysis, and calorimetry. By linking molecular dynamics with macroscopic performance, the work aims to support the development of vitrimers as practical, recyclable materials.
T2 - EPF2025 - European Polymer Congress
CY - Groningen, The Netherlands
DA - 22.06.2025
KW - Polymer recycling
PY - 2025
AN - OPUS4-63859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abel, Andreas
A1 - Zapala, P.
T1 - Materials Applications FeAl (WAFEAL)
N2 - The increasing importance of resource availability and closed-loop material cycles are driving materials research to reduce alloying content in conventional materials or even substitute them with more sustainable alternatives. Intermetallic iron aluminide alloys (FeAl) present a potential alternative. Many alloy concepts for improved high-temperature properties or ductility have already been successfully implemented in casting technologies on a laboratory scale. However, successful testing of FeAl alloys on an industrial scale was still pending at the beginning of the project.
Therefore, the aim of the project was to develop simulation-based casting concepts for industrial casting processes using the base alloy Fe-26Al-4Mo-0.5Ti-1B and to narrow down process limits by means of hot cracking tests. Findings were transferred into practice-oriented guidelines for casting of iron aluminides, which is accessible to future applicants in SMEs. The focus was placed on centrifugal casting combined with investment casting or die casting. In addition to numerous design and casting process parameters, heat treatments and alloying additions (Al, Mo, B) were varied to determine the influence of alloying elements on castability, microstructure and mechanical properties. Data from microstructure analyses (microscopic imaging, determination of grain sizes as well as phase compositions and volume fractions, fractography), mechanical tests (hardness measurements, compression tests, ambient and high-temperature tensile tests, creep tests) as well as measurements of thermophysical properties could be generated on the base alloy. Correlations of materials data with process variables allowed conclusions to be drawn on strengthening mechanisms and ductility of the alloy and how they can be controlled in terms of processing and component design. Successful casting of highly complex components with thin wall thicknesses and optimised alloy compositions points out prospects for new fields of application.
T2 - FVV Transfer + Netzwerktreffen | Informationstagung – Frühjahr 2023
CY - Würzburg, Germany
DA - 29.03.2023
KW - Fe-Al alloys
KW - Intermetallics
KW - Iron aluminides
KW - Microstructure-property-correlation
KW - High temperature mechanical properties
KW - Creep data
KW - Tensile data
KW - Fractography
KW - Casting
PY - 2023
AN - OPUS4-57248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Observation of the weld pool shape in partial penetration welding and its influence on solidification crack formation for high-power laser beam welding
N2 - In this study, steel-glass experiments were conducted to observe the melt pool geometry using a high-speed camera. The high-speed recordings and optical flow analysis show that two main flows take place in form of vortices. The lower vortex drives the melt backwards from the front keyhole wall and thus causes an extension of the melt pool, which is called bulging. This bulging promotes solidification cracking by forming a closed area filled with melt and the accumulation of impurities in the final solidification phase, resulting in low-melting phases which are under tensile stress at the end of solidification.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - Laser beam welding
KW - Weld pool shape
KW - Solidification craking
KW - Partial penetration
PY - 2021
SP - 1
EP - 5
AN - OPUS4-53587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Improving the Reproducibility of Characterization and Quantification of Precipitates through Automated Image Processing and Digital Representation of Processing Steps
N2 - The strength of age-hardenable aluminum alloys is based on the controlled formation of nm-sized precipitates, which represent obstacles to dislocation movement. Transmission electron microscopy (TEM) is generally used to identify precipitate types and orientations and to determine their size. This geometric quantification (e.g., length, diameter) is often performed by manual image analysis, which is very time consuming and sometimes poses reproducibility problems. The present work aims at the digital representation of this characterization method by proposing an automatable digital approach. Based on DF-TEM images of different precipitation states of alloy EN AW-2618A, a modularizable digital workflow is described for the quantitative analysis of precipitate dimensions. The integration of this workflow into a data pipeline concept is also presented. The semantic structuring of data allows data to be shared and reused for other applications and purposes, which enables interoperability.
T2 - ICAA19 International Conference on Aluminum Alloys
CY - Atlanta, GA, USA
DA - 23.06.2024
KW - Digital representation
KW - Automatable digital approach
KW - Digital workflow
KW - Quantitative image analysis
KW - Data pipeline concept
KW - Semantic structuring
KW - Interoperability
KW - FAIR data management
PY - 2024
AN - OPUS4-60427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan-Scherb, Christiane
A1 - Lehmusto, Juho
A1 - Falk, Florian
A1 - Sobol, Oded
A1 - Pint, Bruce
T1 - Comprehensive insights into competitive oxidation/sulfidation reactions on binary ferritic alloys at high temperatures
N2 - Interpreting high-temperature corrosion induced by mixed-gas atmospheres is challenging due to the different contributions of oxidizing gases. Here, a comprehensive study on the combined oxidation/sulfidation using label molecules is presented. Fe-Cr model alloys with 2 wt% and 9 wt% Cr were isothermally exposed using a volumetric mixture of 0.5%S16O2/27%H218O and 0.5%S16O2/7%H218O at 650 ◦C for 5 h and then characterized by secondary ion mass spectroscopy (SIMS). Additionally, the reactions were followed in-situ utilizing energy dispersive X-ray diffraction. The study showed that both S16O2 and H218O contribute to the oxidation of the alloys but to different extents depending on the Cr-content.
KW - SEM
KW - Steel
KW - Iron
KW - SIMS
PY - 2022
DO - https://doi.org/10.1016/j.corsci.2022.110236
SN - 0010-938X
VL - 203
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-58992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - The detrimental molten pool narrowing phenomenon in wire feed laser beam welding and its suppression by magnetohydrodynamic technique
N2 - Element transport in the wire feed laser beam welding (WFLBW) is directly determined by the molten pool shape and thermo-fluid flow therein. In this paper, an untypical molten pool profile, i.e., elongated at its top and bottom but narrowed at the middle, is found experimentally by real-time metal/glass observa- tion and numerically by multi-physical modeling. Ex-situ X-ray fluorescence element mapping is used to characterize the element dilution status in the fusion zone. For the first time, the detrimental influence of the molten pool narrowing on the element transport is identified and discussed, combining the exper- imental and numerical results. A magnetohydrodynamic technique is utilized to suppress the narrowing, aiming at a more homogenous element distribution. It is found that due to the interaction of the two dominant circulations from the top and bottom regions of the molten pool, a low-temperature region is formed. It leads to an untypical growth of the mushy zone, narrowing the molten pool in the middle re- gion. Its detrimental effect on material mixing is non-negligible considering the direct blocking effect on the downward flow and the premature solidification at the middle region. The Lorentz force from a trans- verse oscillating magnetic field can change the flow pattern into a single-circulation type. The downward transfer channel is widened, and its premature solidification is prevented because the low-temperature- gradient region is mitigated. This paper provides a supplementary reason regarding the common issue of insufficient material mixing during LBW, and a promising technique to optimize the process.
KW - Thermo-fluid flow
KW - Element transport
KW - Laser beam welding
KW - Magnetohydrodynamics
KW - Multi-physical modeling
PY - 2022
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2022.122913
VL - 193
SP - 122913
PB - Elsevier B.V.
AN - OPUS4-55006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Richter, Tim
A1 - Mayr, P.
A1 - Nitsche, A.
A1 - Mente, Tobias
A1 - Böllinghaus, Thomas
T1 - Hydrogen diffusion in creep-resistant 9% Cr P91 multi-layer weld metal
N2 - Welded components of P91 9% Cr steel demand for careful welding fabrication with necessary post weld heat treatment (PWHT). Before the PWHT, a hydrogen removal heat treatment is necessary for avoidance of hydrogen assisted cracking (HAC). In this context, the microstructure and temperature-dependent hydrogen diffusion is important, and reliable diffusion coefficients of P91 weld metal are rare. For that reason, the diffusion behavior of P91 multi-layer weld metal was investigated for as-welded (AW) and PWHT condition by electrochemical permeation experiments at room temperature and carrier gas hot extraction (CGHE) from 100 to 400 °C. Hydrogen diffusion coefficients were calculated, and the corresponding hydrogen
concentration was measured. It was ascertained that both heat treatment conditions show significant differences. At room
temperature the AW condition showed significant hydrogen trapping expressed by to seven times lower diffusion coefficients. A preferred diffusion direction was found in perpendicular direction expressed by high permeability. The CGHE experiments
revealed lower diffusion coefficients for the AW condition up to 400 °C. In this context, a hydrogen concentration of approximately 21 ml/100 g was still trapped at 100 °C. For that reason, a certain HAC susceptibility of as-welded P91 weld metal cannot
be excluded, and hydrogen removal should be done before PWHT.
KW - Creep resisting materials
KW - Diffusion
KW - Hydrogen
KW - Weld metal
KW - Post weld heat treatment
KW - Microstructure
PY - 2020
DO - https://doi.org/10.1007/s40194-019-00828-8
SN - 0043-2288
VL - 64
IS - 2
SP - 267
EP - 281
PB - Springer
AN - OPUS4-50471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Portella, Pedro Dolabella
A1 - Skrotzki, Birgit
A1 - Muth, Thilo
T1 - Die Digitalisierung der Materialwissenschaft und Werkstofftechnik - ein Überblick
N2 - Die Bereitstellung von zuverlässigen Werkstoffdaten stand für die Werkstoffprüfung seit dem 19. Jahrhundert in zentraler Stelle. Mit der zunehmender Digitalisierung unserer Gesellschaft gewinnt das Datenmanagement insbesondere im Hinblick auf die Modellierungs- und Simulationsaktivitäten an Bedeutung.
In unserem Beitrag beschreiben wir die gegenwärtigen Aktivitäten in Deutschland – insbesondere die NFDI-MatWerk und die BMBF-Initiative MaterialDigital – sowie in Europa und Übersee. Abschließend heben wir die Auswirkungen auf die technische und akademische Aus- und Weiterbildung.
T2 - DVM - Tagung Werkstoffprüfung
CY - Online meeting
DA - 03.12.2020
KW - Werkstoffdaten
KW - Digitalisierung
KW - Materialwissenschaft
PY - 2020
AN - OPUS4-52044
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Koerdt, Andrea
T1 - The impact and potential of halophilic microorganisms on alternative fuels
N2 - As more industrial interests focusing on using salt caverns and repurposed gas or petroleum reservoirs for alternative fuel storage, i.e. CO2/H2, the question raises whether microorganisms may impact the infrastructure, gas purity and storage condition over time.
Environments with high salinity (> 1.5 Meq of NaCl) are resided by halophiles (salt-loving microorganisms). To compensate for the intensive osmotic stress, they have resorted to two main adaptation strategies: 1) production of compatible solutes and 2) accumulation of intracellular KCl. Microbial community analysis of several high salinity environments revealed a number of recurring genera, including Halomonas and Halanaerobium. However, the impact of halophiles on the overall integrity and stability of the storage facilities remain largely unknown.
To evaluate the suitability and stability of saline storage facilities, several model halophilic microorganisms, such as members of Halomonas, will be selected as testing subjects. First, the impact of halophiles on the infrastructure will be determined using an integrative approach by combining a number of techniques, including electrochemistry, TOF-SIMS, SEM/FIB/EDS and FIB-TEM. Second, the abilities of halophiles to alter the fuel composition (i.e. increase/decrease the fractions of H2) will be monitored using gas chromatography by growing them under high pressure.
As a result of climate change and the accompanying mandatory shift to renewable energy resources, microorganisms will continue to play an important role in the energy sector, both to their benefit and detriment. Thus, it is important to achieve a certain level of understanding regarding the activities and mechanisms of halophiles prior to large-scaled excursions.
T2 - ISMOS-8
CY - Online meeting
DA - 07.06.2021
KW - Microbiologically influenced corrosion
KW - Hydrogen
KW - Gas storage
KW - Contamination
PY - 2021
AN - OPUS4-52891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dittmann, Daniel
T1 - Aktivkohle-Charakterisierung als weiterer Schlüssel für das Verständnis der Spurenstoffadsorption in der 4. Reinigungsstufe
N2 - Aktivkohle ≠ Aktivkohle, Adäquate Materialcharakterisierung - Voraussetzung für Adsorptionsprognosen und Wasserspezifische Auswahl von Aktivkohleprodukten.
Ausblick: Publikationen zu Aktivkohlecharakterisierung und Adsorptionsprognose in Vorbereitung
T2 - Wasser 2021 - Jahrestagung der Wasserchemischen Gesellschaft
CY - Online meeting
DA - 10.05.2021
KW - Aktivkohle
KW - Thermogravimetrie
KW - Zersetzungsgasanalyse
KW - Proximatanalyse
PY - 2021
AN - OPUS4-52742
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Durlo Tambara, Luís Urbano
A1 - Lima, G. T. S.
A1 - Silvestro, L.
A1 - Ruviaro, A. S.
A1 - Gleize, P. J. P.
A1 - de Azevedo, A. R. G.
T1 - Influence of polycarboxylate superplasticizer and calcium sulfoaluminate cement on the rheology, hydration kinetics, and porosity of Portland cement pastes
N2 - Binary systems composed of Portland cement (PC) and calcium sulfoaluminate (CSA) cement have stood out for applications requiring high early strengths. Nevertheless, the application of these systems may be limited due to their properties in the fresh state, which requires a better understanding of the rheological behavior of these materials. Thus, this study evaluated the incorporation of different polycarboxylate-based superplasticizer (SP) contents (0.15, 0.20, and 0.25 wt%) on PC and PC-CSA binary cement pastes. Rotational rheometry, isothermal calorimetry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption and desorption tests to assess the pore size distribution of cement pastes were conducted. While the SP incorporation reduced the dynamic yield stress of PC pastes, it progressively increased the yield stress of PC-CSA systems. The increase in SP content increased the main heat flow peak of PC-CSA pastes, although it did not significantly affect the cumulative heat after 160 h of hydration. FTIR and XRD confirm higher ettringite contents in the binary systems and indicate the presence of carboaluminates phases after 7 d of hydration in both PC and PC-CSA and hemicarboaluminate in PC-CSA pastes. The CSA incorporation reduced the cumulative pore volume by up to 32% compared to PC pastes, while the SP content evaluated did not significantly affect the porosity of PC-CSA pastes.
KW - Calcium sulfoaluminate cement
KW - Portland cement
KW - Superplasticizer
KW - Rheology
KW - Hydration
PY - 2023
DO - https://doi.org/10.1016/j.jobe.2023.106120
SN - 2352-7102
VL - 68
SP - 1
EP - 15
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-57034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hébrard, Louis
T1 - Comparison of Room and High Temperature Fatigue Behavior of a New LPBF VDM 780 Alloy
N2 - The actual environmental challenges require a huge effort from all industrial sectors to reduce their emissions of greenhouse gasses and pollutants. In this context, aeronautics is deeply concerned as one of the most emissive industrial sectors (cf. EU Green Deal). The answer to this pressing challenge is complex and involves new fuels and engine concepts, new aerostructures with higher weight-savings, as well as new, energy-efficient, and sustainable manufacturing technologies and materials. Two technologies may contribute particularly to achieving the goals: (i) new and more energy-efficient processes such as additive manufacturing (AM) can be used for part production; (ii) the engine efficiency of airplanes can be significantly improved to save fuel and reduce gas emissions. The latter can be achieved by increasing the engine thermal efficiency, i.e., increasing the turbine inlet temperature. Currently, only single-crystalline cast materials are available to be used for the thermally highest-loaded parts in the gas turbine engine, i.e., the turbine blades in the high-pressure turbine just behind the combustion chamber. These materials rely on a special casting technology, although they lose these original material performances when additive manufactured. In addition, current materials suitable for metal additive manufacturing have a limited range of temperature application. Therefore, the focus is on the development of new materials targeting higher in-service operation temperatures and durability. Recently, a new Ni-based superalloy (VDM 780) has been developed to ensure microstructural stability up to 800 °C. The goal of this work is to provide a deeper understanding of the high temperature fatigue properties of this alloy. This will enable the identification of the maximum operating temperature of this alloy and assess its performance in order to establish its potential in view of a new generation of more efficient aero-engines.
T2 - 11th Edition of Fatigue Design International Conference
CY - Senlis, France
DA - 19.11.2025
KW - Fatigue
KW - Additive Manufacturing
KW - Ni-based superalloy
KW - High Temperature
PY - 2025
AN - OPUS4-64992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blasón Gonzalez, Sergio
A1 - Werner, Tiago
A1 - Kruse, Julius
A1 - Gilli, D.
A1 - Madia, Mauro
T1 - Procedimiento experimental para la determinación del valor ΔK umbral intrínseco y caracterización de velocidad de propagación de grietas en fatiga en probetas de acero
N2 - Se presenta una guía completa del procedimiento experimental para la determinación del valor umbral ΔKth intrínseco y caracterización de curvas FCGR sobre el acero de alta resistencia S960QL empleando probetas de pequeña escala. El análisis se realiza comparando probetas SENB de diferentes geometrías, distinguiendo entre “convencionales” y “miniatura”. Las primeras con espesor (B) de 6 mm y anchura (W) de 19, y las segundas con B = 3 y dos valores distintos de W, 4 y 6 mm. A fin de identificar el valor umbral ΔKth intrínseco, la relación de cargas (R) aplicada en todos los ensayos fue 0,8. La técnica de caída de potencial (DCPD) se utilizó para la monitorización del tamaño de grieta a lo largo de los ensayos.
La evaluación de los resultados experimentales confirma la equiparación de resultados entre las distintas geometrías y configuraciones de ensayo practicadas, así como la viabilidad de emplear probetas de pequeña escala en la determinación del valor umbral ΔKth intrínseco. Esto abre nuevas perspectivas en lo relativo al empleo de probetas de reducidas dimensiones en la caracterización de materiales a fatiga. A su vez, permite ofrecer una serie de recomendaciones para reproducir con éxito ensayos semejantes utilizando probetas de pequeñas dimensiones de acero y otros materiales metálicos.
T2 - XXXVII Congreso del Grupo Español de Fractura
CY - Online meeting
DA - 07.06.2021
KW - Probetas miniatura
KW - Determinación Kth intrínseco
KW - Curvas FCGR
KW - Acero alta resistencia
KW - Recomendaciones procedimiento de ensayo
PY - 2021
AN - OPUS4-55244
LA - spa
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Structural integrity of cold spray repaired aerospace components
N2 - Components in aircrafts are usually replaced when critical defects are present.
An alternative approach is repairing using gas dynamic cold spraying: metal particles are shot at a surface at supersonic speeds to selectively rebuild damaged material. Compared to other material-deposition techniques, its advantage is the small thermal impact on the component, preserving its mechanical properties.
Component-repair can save considerable amounts of energy and resources. However, its industrial application at large scale needs reproducible, good repair-material properties to guarantee a safe component life. The aim of this project is the development of safe, automatized repair-procedures considering the mechanical fatigue properties of the repair.
T2 - ICEAF VII Conference 2023
CY - Spetses, Greece
DA - 21.06.2023
KW - Cold Spray
KW - Repair
KW - Fatigue
KW - Fatigue Crack Growth
KW - Slow Strain Rate Testing
PY - 2023
AN - OPUS4-57784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Roveda, Ilaria
T1 - Effect of heat treatment on the microstructure, residual stress state and fatigue properties of PBF-LB/M AlSi10Mg
N2 - Al-Si alloys produced by Laser Powder Bed Fusion (PBF-LB/M) techniques allow the fabrication of lightweight free-shape components. Due to the extremely heterogeneous cooling and heating, PBF-LB/M induces high magnitude residual stress (RS) and a fine Si microstructure. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their evolution before and after post-process heat treatments (HT).
T2 - Alloys for Additive Manufacturing Symposium 2022 (AAMS22)
CY - Munich, Germany
DA - 12.09.2022
KW - Neutron diffraction
KW - X-ray diffraction
KW - Crack propagation
PY - 2022
AN - OPUS4-55871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - A parametric study of the laser energy absorption in high power laser beam welding
N2 - Laser energy absorption on the keyhole wall is decisive for the thermodynamic behavior and the resultant weld properties in the high-power laser beam welding process. However, its highly transient nature on a microsecond scale makes the quantitative analysis challenging. In this paper, the influence of the relevant welding parameters on laser energy absorption is studied statistically by utilizing multiphysical modeling, in which the three-dimensional transient keyhole dynamics and thermo-fluid flow are calculated. A dynamic mesh adaption technique and a localized level-set-based ray-tracing method are employed to improve the model accuracy further. The results show that the focus position has a remarkable effect on the time-averaged laser absorption, and in contrast, the laser energy distribution regime is only slightly influenced by the welding speed in the studied parameter range (1.5–3.0 m/min). The absorption ratio of the laser energy on the keyhole front wall decreases with increasing welding speed and increases with upward-moving focus positions. The comparison between the calculated results and the experimental measurements ensures the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 03.11.2024
KW - Laser beam welding
KW - Laser energy absorption
KW - Weld pool
KW - Parametric study
KW - Multiphysics modeling
PY - 2024
AN - OPUS4-61619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Der Weg zur Standardisierung der Hohlzugtechnik für die Nutzung mit gasförmigem Wasserstoff
N2 - Dieser Kurzvortrag stellt selektierte Ergebnisse des Projektes "H2Hohlzug" im übergeordneten Projekt "TransHyDE" kurz vor. Insbesondere wird auf die Herausforderung eingegangen, wiederholbare Prüfbedingungen unter Druckwasserstoffbeanspruchung, einzuhalten.
T2 - Herbstsitzung des DGM Arbeitskreises "Materialprüfung unter Wasserstoff"
CY - Dortmund, Germany
DA - 19.11.2024
KW - Hohlzugprobe
KW - Wasserstoff
KW - Materialprüfung
KW - Standardisierung
PY - 2024
AN - OPUS4-61718
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Jentzsch, Stefan
A1 - Stock, Daniel
A1 - Häcker, Ralf
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
A1 - Klingbeil, Dietmar
A1 - Kindrachuk, Vitaliy
T1 - Split Hopkinson Pressure Bar (SHPB) investigations of steel S355 specimens and complementary characterization methods
N2 - The workbook SHPB_S355.xlsx contains in the main spreadsheet S355_TestOverview an overview on the S355 specimens, which were tested in Split Hopkinson Pressure Bar (SHPB) and complementary quasi-static (QS) tests. The tests were conducted with notched hat-shaped specimens without a notch offset (S355_TestOverview/column geometry: “no offset”) and a small notch offset of x=0.35 mm (S355_TestOverview/column geometry: “offset”), cf. Fig. 1 [1]. Furthermore, for selected specimens, links are provided to DIC and bar strain measurement files as well as to evaluations from further characterization methods (microhardness, EBSD). For the boundary conditions at the SHPB projectile impact, the pressures of the compressor p, driving the projectile, and the associated projectile impact velocities are provided in SHPB_S355.xlsx.
The DIC displacement measurements are provided in FurtherMeasurements/DIC with frame output times in the file labels, which are associated with an imaginary trigger at the left end of the shortened incident bar (length 300 mm), which is considered within the SHPB simulation setup, see [1]. Furthermore, the DIC reference coordinate systems are provided as COS.jpg files in the respective DIC folders.
Starting from the strain signals at the bars, captured by strain gauges at the incident (file name BC_Inc) and transmission bar (BC_Trans), displacement boundary conditions (which are provided for the tests in FurtherMeasurements/BarDisplBCs) are calculated by eq. (12) in [1], incorporating the acoustic velocity equal to 4639 m/s at the bars and a correction factor. Fig. 1 shows the shear specimen geometry (lengths in mm) with the offset of the notches x.
For the quasi-static tests force(displacements)-values are directly provided in FurtherMeasurements/Fu_curves, which are considered from the relative displacements of the specimens, evaluated by DIC.
The Vickers microhardness (HV 0.01) distribution across the shear localization zone was assessed by QNESS 60A+ EVO (DIN EN ISO 6507-1) for quasi-statically and dynamically tested specimens, applying the small notch offset, such that the specimens did not fail in the localization region. Therefore, raw data is provided in FurtherMeasurements/Microhardness. For fitting the microhardness distribution perpendicularly to the shear bands (as i.e. provided for the SHPB specimen in [1]), representative microhardness profiles were considered. Similarly for specimens with the small notch offset, EBSD data on dynamic and quasi-static tests is provided in FurtherMeasurements/EBSD. The grain size distributions for positions at the notch and the undeformed region are included in the subdirectory ./GrainLists_Shortened and EBSD images in the PowerPoint Presentations. Further information as the sizes and misorientations of the single grains, is incorporated in the subfolders ./GrainLists_FurtherInf.
KW - Adiabatic shear bands
KW - Split Hopkinson pressure bar
KW - Digital image correlation
PY - 2025
DO - https://doi.org/10.5281/zenodo.17591439
PB - Zenodo
CY - Geneva
AN - OPUS4-64842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
T1 - Measurement of thermal cycle and layer hight at multi-pass build-up during LMD-Process
N2 - The shape of the parts, created by the technology of laser metal deposition (LMD), is influenced by various parameters, for example, the power and diameter of the laser source spot. The contribution of energy from the laser affects the temperature distribution in the formed layers. The changing temperature in the working area entails a change in the geometry of the layers and affects the stability of the process. In this paper, experiments on the measurement of temperature cycles in the DLMD process with different directions of the filling track are carried out. An infrared camera was used to measure thermal cycles. The calibration of the acquired data (i.e. correspondence table between the intensity of thermal radiation of the material and the absolute temperature) was done with help of two-color pyrometer ex situ and in situ measurements. The experiments are carried out on two materials 316L and Inconel 718. The effect of the maximum temperature on the layer height is shown, and thermal cycles in the formation of layers for different filling strategies are presented.
T2 - 1st Workshop on in-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online meeting
DA - 11.12.2020
KW - Laser metal deposition
KW - AISI 316L
KW - Alloy 718
KW - Thermography
PY - 2020
AN - OPUS4-51816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
A1 - Madia, Mauro
A1 - Schurig, Michael
A1 - Fedelich, Bernard
A1 - Schlums, H.
A1 - Zerbst, Uwe
T1 - Burst Behaviours Of Aero Engine Turbine Disk At Overspeed Conditions
N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on production-similar disks. The aim of this work is to present part of a fracture mechanics-based procedure under development which aims at replacing the tests on production-similar disks with lab tests on fracture mechanics specimens. The finite element simulation of the cracked disk considers the real thermal and mechanical loading conditions. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of 𝐽-integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. This has been achieved and as expected, both the highest 𝐽 -integral and constraint factor are calculated at the same location along the crack front for both disk and specimen. The results of the structural integrity assessment in the form of a Failure Assessment Diagram (FAD) show good agreement between designed specimen and disk both in terms of expected failure mode and value of the critical speed. In addition, probabilistic aspects are also considered in the calculations.
T2 - 43rd Int. Conference on Materials Mechanics, June 5-10, 2022, Greece
CY - Sani, Chalkidiki, Greece
DA - 05.06.2022
KW - Structural integrity
KW - Turbine disk
KW - Fracture mechanics
KW - Overspeed
PY - 2022
SP - 1
EP - 13
AN - OPUS4-57279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strobl, Dominic
T1 - Reduced Order Model with Domain Mapping for Temperature Field Simulation of Wire Arc Additive Manufacturing
N2 - Additive manufacturing (AM) has revolutionized the manufacturing industry, offering a new paradigm to produce complex geometries and parts with customized properties. Among the different AM techniques, the wire arc additive manufacturing (WAAM) process has gained significant attention due to its high deposition rate and low equipment cost. However, the process is characterized by a complex thermal history, dynamic metallurgy, and mechanical behaviour that make it challenging to simulate it in real-time for online process control and optimization.
In this context, a reduced order model (ROM) using the proper generalized decomposition (PGD) method is proposed as a powerful tool to overcome the limitations of conventional numerical methods and enable the real-time simulation of the temperature field of WAAM processes. Though, the simulation of a moving heat source leads to a hardly separable parametric problem, which is handled by applying a novel mapping approach. Using this procedure, it is possible to create a simple separated representation of the model, also allowing to simulate multiple layers.
In this contribution, a PGD model is derived for the WAAM procedure simulating the temperature field. A good agreement with a standard finite element method is shown. The reduced model is further used in a stochastic model parameter estimation using Bayesian inference, speeding up calibrations and ultimately leading to a calibrated real-time simulation.
T2 - SIM-AM 2023
CY - Munich, Germany
DA - 26.07.2023
KW - Additive manufacturing
KW - Reduced Order Model
PY - 2023
AN - OPUS4-58253
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blasón Gonzalez, Sergio
A1 - Chaudry, Mohsin Ali
A1 - Elorriaga, A.
A1 - Madia, Mauro
A1 - Llavori, I.
A1 - Hilgenberg, Kai
T1 - Diseño de componentes fabricados aditivamente basado en propiedades locales del material
T1 - Design of additively manufactured components based on locally representative material fatigue properties
N2 - La tecnología de fabricación aditiva (AM) continúan progresando y permitiendo alcanzar diseños cada vez más complejos y optimizados. La industria química es uno de los sectores donde componentes AM han adquirido un gran interés. La falta hasta la fecha de una directiva europea que regule la inspección, certificación y aceptación de equipos sometidos a presión hace necesario progresar en esta línea. El objetivo que se persigue en este trabajo es el de desarrollar una metodología de diseño sobre componentes fabricados aditivamente basada en la estimación de vida a fatiga de las zonas más susceptibles de sufrir dicho tipo de fallo. El estudio comprende diversas facetas de análisis, simulaciones numéricas, análisis de la microestructura del material y una extensa campaña experimental. La evaluación de la integridad estructural se realiza aplicando mecánica de fractura. La historia térmica a lo largo del proceso de fabricación determina la microestructura del componente en cada región y, por ende, influye en las propiedades mecánicas en cada una. Se presentan los resultados preliminares de un proyecto de investigación en curso dirigido a la caracterización de propiedades mecánicas en recipientes de presión producidos por fusión láser en lecho de polvo (L-PBF, por sus siglas en inglés) de acero inoxidable 316L. Se detallan los resultados preliminares en términos de velocidad de crecimiento de grietas por fatiga (FCGR), y se comparan los resultados de probetas extraídas de diferentes regiones de los depósitos.
N2 - Additive manufacturing (AM) technology continues to make progress and allows for reaching increasingly complex and optimised designs. The chemical industry is one of the sectors where AM components have acquired relevance. There is a lack of any European directive in order to regulate the inspection, certification as well as acceptance of additively manufactured (AM) equipment subjected to pressure loads, so progression in this line becomes necessary. This work aimed to develop a design methodology for AM components based on the estimation of fatigue lifetime on those regions with a higher risk of failure. Diverse facets are involved in this study, including numerical simulations, microstructure analysis and an extensive experimental campaign. The fatigue assessment is performed based on fracture mechanics. The microstructure characteristics are dependent on the thermal history along the manufacturing process for each region and, accordingly, the mechanical properties are likewise influenced. Preliminary results of an ongoing research project for characterizing the mechanical properties in demonstrator pressure vessels produced by laser powder bed fusion (L-PBF) on stainless steel 316L are presented. The preliminary findings obtained in terms of fatigue crack growth rate (FCGR) and are detailed. Results from specimens extracted from different regions of the vessel are compared.
T2 - 5th Iberian Conference on Structural Integrity IbCSI 2022
CY - Coimbra, Portugal
DA - 30.03.2022
KW - Fabricación Aditiva
KW - Additive Manufacturing
KW - Acero 316L
KW - Mecánica de Fractura
KW - Predicción vida a fatiga
KW - Fit4AM
KW - Steel 316L
KW - Fracture Mechanics
KW - Fatigue lifetime prediction
PY - 2022
AN - OPUS4-55241
LA - spa
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blasón Gonzalez, Sergio
A1 - Chaudry, Mohsin Ali
A1 - Elorriaga, A.
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Llavori, I.
A1 - Hilgenberg, Kai
T1 - Design methodology of vessel produced by L PBF stainless steel using representative specimens
N2 - This work presents the preliminary results of an ongoing project with a double objective: on the one hand, the characterisation of the mechanical properties against fatigue damage of an additively manufactured 316 stainless steel produced by laser powder bed-based (L-PBF) technology; on the other hand, the implementation of numerical simulation techniques able to predict the mechanical behaviour of the material in order to optimise and reduce the design costs of vessels used in the chemical sector. The current state of the work developed in this research framework allows showing the first batch of experimental results of crack propagation rate (FCGR) and high cycle fatigue (HCF) tests. The geometry of the vessels studied presents three clearly differentiated regions, either in terms of thickness (11-15 mm) or concerning the inclination of the walls to the direction of manufacturing (0º - 45º). The experimental campaign carried out so far allows identifying the differences in behaviour when comparing different extraction locations around the vessel. This is due to the variations in thermal cycles that the deposited material undergoes during the manufacturing process. Therefore, this causes variations in the microstructure which lead to changes in the response of the material. In this work, these differences are analysed qualitatively and quantitatively from the results of FCGR and HCF, thus allowing to locate the regions with the highest risk in terms of structural integrity against fatigue. This preliminary phase together with the numerical simulation of the additive manufacturing process are key to achieving a reliable description and modelling of the material. The latter will make it possible to address the priority aim of this project, involving the manufacture of independent samples whose properties are representative of the original material extracted from the reference vessels. It is, therefore, a comprehensive methodology for the design of additively manufactured components based on the localised fatigue mechanical properties of representative specimens.
T2 - ECF23, European Conference on Fracture 2022
CY - Funchal, Portugal
DA - 27.06.2022
KW - Additive manufacturing
KW - Steel 316L
KW - Fracture Mechanics
PY - 2022
AN - OPUS4-55240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falk, Florian
A1 - Sobol, Oded
A1 - Stephan-Scherb, Christiane
T1 - The impact of the microstructure of Fe-16Cr-0.2C on high-temperature oxidation – sulphidation in SO2
N2 - This study elucidates the impact of the microstructure of Fe-16Cr-0.2C on oxide layer formation at 650 ◦C in Ar-0.5 % SO2. A cold-rolled and two heat-treated states of the alloy were exposed for up to 1000 h. The samples were characterised in detail from microstructural and chemical perspectives using scanning electron microscopy (SEM), X-ray diffraction (XRD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The microstructural modification of the alloy by heat-treatment was advantageous. It was found that Cr-carbides support chromia formation and reduce sulphidation when their area fraction is low and diameter is small.
KW - Steel
KW - Iron
KW - SIMS
KW - SEM
KW - High temperature corrosion
KW - Oxidation
KW - Sulphidation
PY - 2021
DO - https://doi.org/10.1016/j.corsci.2021.109618
VL - 190
SP - 109618
PB - Elsevier Ltd.
AN - OPUS4-53001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Die Hohlzugprobentechnik - Eine neue Methodik zur Untersuchung der Materialverträglichkeit unter Wasserstoffeinfluss
N2 - Die schädigende Wirkung von Wasserstoff auf die mechanischen Eigenschaften von Stählen ist zwar bekannt, aber noch immer nicht ausreichend erforscht. Die schnelle und sichere Markteinführung von Wasserstofftechnologien macht es erforderlich, dieses Thema genauer zu untersuchen. Im Allgemeinen wird dies oft als Wasserstoffversprödung bezeichnet. Daher ist es wünschenswert, eine Prüfmethode zu entwickeln, die auf einfache Weise die Materialeigenschaften unter Wasserstoffatmosphäre ermitteln kann. Derzeit werden mechanische Prüfungen unter Wasserstoffatmosphäre in Autoklaven durchgeführt. Für diese Technik ist eine aufwendige Hardware erforderlich, daher sind die Prüfungen teuer und die Prüfkapazitäten nur in geringem Umfang verfügbar. Die hier vorgestellte Prüfmethode verspricht einen zukunftsweisenden Ansatz zur Reduzierung von Kosten und Bearbeitungszeiten durch die Verwendung von Hohlkörpern, d.h. die Probe selbst stellt den Autoklav dar.
T2 - Sitzung des DIN-Gemeinschaftsarbeitsausschusses NA 092 00 05 GA, NAS/NMP: Zerstörende Prüfung von Schweißverbindungen
CY - Berlin, Germany
DA - 15.03.2023
KW - Prüfung
KW - Wasserstoff
KW - Probengeometrie
KW - Hochdruck
PY - 2023
AN - OPUS4-57168
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Konert, Florian
A1 - Nietzke, Jonathan
T1 - Application of an in-situ H2Test Method
N2 - The degradation effect of hydrogen on the mechanical properties of steels is well known, but still not sufficiently understood. The fast and safe market ramp up of hydrogen technologies makes it evident to evaluate a wider understanding of this topic. In general it is often described as hydrogen embrittlement. Therefore it is desirable to achieve a test method which is able to provide material properties under hydrogen atmosphere in an easy way. Currently mechanical tests under hydrogen atmosphere are executed in autoclaves. For this technique complex hardware is needed, therefore tests are expensive and test capacities are only available in a small scale. The shown test method promises a trendsetting approach for reducing costs and machine time by using hollow specimen.
T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022
CY - Ghent, Belgium
DA - 11.10.2022
KW - Hydrogen
KW - Hollow specimen
KW - In-situ
KW - Test procedure
PY - 2022
AN - OPUS4-56032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Einfluss von Oberflächenbeschichtungen auf die flüssigmetallinduzierte Rissbildung beim Widerstandspunktschweißen von hochfesten Stahlfeinblechen
BT - Schlussbericht vom 15.09.2022 zu IGF-Vorhaben Nr. 20812 N : Berichtszeit: 01.10.2019 bis 31.03.2022
N2 - Die Beschichtung hochfester Stahlfeinbleche beeinflusst das Auftreten von flüssigmetallinduzierter Rissbildung (LME). Daher wurden in dieser Arbeit industrieübliche Beschichtungen bei gleichem Grundwerkstoff hinsichtlich ihres Aufbaus und chemischer Zusammensetzung charakterisiert und bezüglich ihrer LME Anfälligkeit untersucht. Aus dieser vergleichenden Untersuchung heraus wurden Potentiale für die Widerstandsfähigkeit gegen LME identifiziert. Diese Potentiale werden experimentell durch den Einsatz einer von der Forschungsstelle entwickelten Methode überprüft. Gegenstand der Untersuchungen waren neben unbeschichteten Proben industrieübliche Zinküberzüge wie Elektrolytisch verzinkt, Feuerverzinkt, Galvannealed und Zink-Magnesium Beschichtungen.
Die LME Anfälligkeit dieser unterschiedlichen Überzüge wird mit einem Schweißen unter Zugbelastung Versuchsaufbau untersucht. Dabei ergibt sich die resultierende Anfälligkeit aus den auftretenden Risslängen und der Auftrittswahrscheinlichkeit von LME bei den einzelnen Versuchen. Es konnte eine LME Anfälligkeits-Rangfolge für die Zinküberzüge festgestellt werden. Zink-Magnesium Beschichtungen galten als besonders LME Anfällig, gefolgt von Feuerverzinkt und Galvannealed. Die größte LME Resistenz wurde bei elektrolytisch verzinkten Proben festgestellt.
Aus den Ergebnissen werden Handlungsempfehlungen zur Erhöhung der Verarbeitungssicherheit bzw. Schweißpunktqualität abgeleitet.
KW - Widerstandspunktschweißen
KW - Hochfester Stahl
KW - Liquid Metal Embrittlement
KW - Flüssigmetallinduzierte Rissbildung
KW - Zink
PY - 2022
SN - 978-3-96780-030-2
SP - 1
EP - 39
PB - Forschungsvereinigung Stahlanwendung e. V.
CY - Düsseldorf
AN - OPUS4-58060
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Schönherr, J. A.
A1 - Geilen, M. B.
A1 - Klein, M.
A1 - Oechsner, M.
T1 - Recent developments in the determination of fatigue crack propagation thresholds
N2 - The impact of crack closure and environmental effects on the experimental determination of the fatigue crack propagation threshold is a major problem for the assessment of cyclically loaded components, especially at low stress ratios 𝑅. In this work, the influence of the experimental procedure and air humidity on d𝑎∕d𝑁 − 𝛥𝐾 data at different 𝑅 is discussed. Unlike the results at 𝑅 = −1, the threshold values obtained at 𝑅 ≈ 0.8, i.e. under negligible crack closure levels, show a very small scatter band regardless of the variation of the test parameters and environmental conditions.
KW - Fatigue crack propagation threshold
KW - Component assessment
KW - Crack closure
KW - Environmental effects
KW - Testing parameters
PY - 2022
DO - https://doi.org/10.1016/j.ijfatigue.2022.107131
SN - 0142-1123
VL - 164
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-55403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - von Hartrott, Philipp
A1 - Skrotzki, Birgit
T1 - Room temperature and elevated temperature tensile test and elastic properties data of Al-alloy EN AW-2618A after different aging times and temperatures
N2 - The dataset contains two types of data: elastic properties (Young's and shear modulus, Poisson's ratio) between room temperature and 250 °C and a set of tensile tests at different aging times, aging temperatures, and test temperatures.
KW - Aluminium alloy
KW - Young's modulus
KW - Shear modulus
KW - Aging
KW - Tensile test
KW - Strength
PY - 2023
UR - https://doi.org/10.5281/zenodo.10377164
DO - https://doi.org/10.5281/zenodo.10377163
PB - Zenodo
CY - Geneva
AN - OPUS4-59161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buljak, Vladimir
A1 - Fritsch, Tobias
A1 - Bruno, Giovanni
T1 - Application of inverse analysis for characterization of local material properties in additively manufactured lattice structures
N2 - An inverse analysis (IA) procedure was coupled with X-ray Computed Tomography (XCT) data of lattice structures to identify the materials parameters of the lattice and successively predict the macroscopic behaviour of larger structures. The materials parameters were identified by minimizing the deviation between experimental and FEM simulated force–displacement data of a lattice unit cell; the same parameters were input to the simulation of the force–displacement behaviour of larger cells. The agreement between such simulations and the experimental data proved to be excellent. Since both the small- and large-scale cells were tested along the build direction, a simple isotropic material model was considered adequate to rationalize the experimental results. The approach proved that the IA and the FEM simulations are extremely powerful for material parameter identification and for the prediction of the mechanical behaviour of larger structures. We found that the materials parameters of PBF-L IN625 lattices substantially differ from the bulk properties. The latter cannot be used for FEM calculations.
KW - X-ray computer tomography
KW - Finite element modelling
KW - Large deformation
KW - IN625 nickel alloy
KW - Compression tests
KW - Digital volume correlation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659387
DO - https://doi.org/10.1007/s40964-026-01654-3
SN - 2363-9512
SP - 1
EP - 8
PB - Springer International Publishing
CY - Cham
AN - OPUS4-65938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hörmann, Anja Franziska
T1 - Extending the MOUSE in spirit: Lifecycle of a GIXS experiment
N2 - We present the new grazing incidence mode at the MOUSE, which adapts and extends the MOUSE methodology developed for transmission X-ray scattering (Smales and Pauw, 2021). Our methodology begins and ends in discussion with our users and embraces automation for reproducible experiments including sample organisation, instrument configuration, documentation and data processing. Our innovations address repeatability of measurements via laser-cut labels and an automated record of sample visual appearance. We further discuss our sample alignment routine and conclude with the example of 100 nm diameter spheres whose diameter we could resolve successfully on silicon substrate as well as polished stainless steel.
T2 - SAXS excites
CY - Graz, Austria
DA - 13.04.2026
KW - Grazing incidence
KW - Reproducibility
KW - X-ray scattering
KW - MOUSE
PY - 2026
AN - OPUS4-65937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Sanghamitra
A1 - Chaurasia, Prashant Kumar
A1 - P K, Diljith
A1 - De, Amitava
T1 - Probing build profile in wire arc directed energy deposition
N2 - An easy-to-use methodology for a prior estimation of the overlapping track profile during wire arc directed energy deposition is in ever-demand to assess the dimensional consistency of the fabricated part. A novel analytical framework is proposed here to compute the cross-section of a deposited track, considering the spread of molten filler wire volume on a substrate until solidification. The final track cross-section is obtained as a function of the surface tension force, viscous force, and the contact angle between the liquid filler wire droplet and the substrate. The profile of multiple overlapping tracks is estimated further, considering the remelting of the adjacent tracks. The analytically computed build profiles are compared with the experimentally measured results for different process conditions. The model predicts the width and height of the single-track deposits with average errors of approximately 5% and 14%, respectively, while the multi-track widths are estimated with an error ranging between 2% to 9%. The proposed computational framework serves as a reliable mechanistic model for an effective design of the wire arc directed energy deposition process with improved part quality.
KW - DED-Arc
KW - Wire arc additive manufacturing
KW - Track profile
KW - Analytical model
KW - Experimental measurement
PY - 2026
DO - https://doi.org/10.1080/09507116.2026.2646280
SN - 0950-7116
SP - 1
EP - 12
PB - Taylor & Francis
CY - London [u.a.]
AN - OPUS4-65940
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Experimental and numerical investigations of suppression mechanisms by an oscillating magnetic field on process porosity during laser beam welding
N2 - The magnetohydrodynamic (MHD) technology is recognized as a promising approach for improving the quality of deep penetration laser beam welding. This study employs experimental and numerical methods to investigate the effects of an auxiliary oscillating magnetic field on reducing porosity in the laser beam welding of 5754
aluminum alloy. The experimental results clearly demonstrate a significant reduction of 97% in the porosity ratio of the welded joints applied with an oscillating magnetic field compared to those without magnetic field, thereby validating the efficiency of applying MHD technology in mitigating porosity during the laser beam welding process. In addition, a transient 3D multi-physical model has been developed, integrating the MHD model and metal vapor plume, to gain a more comprehensive understanding of the porosity suppression mechanism. The weld pool shape is significantly widened and enlarged because of the Lorentz force, which facilitates the escape of gas bubbles. Meanwhile, the introduction of an oscillating magnetic field generates a time-averaged downward Lorentz force. This averaged downward Lorentz force, in turn, enhances and stables the downward fluid flow, which hinders the bubble backward movement. Meanwhile, this averaged downward Lorentz force induces an upward electromagnetic expulsive force on the bubble, which effectively increases the upward escape velocity of bubbles in the weld pool. The simulation results agree well with the experimental results.
T2 - 44. Assistentenseminar Füge- und Schweißtechnik
CY - Päwesin, Germany
DA - 20.09.2023
KW - Laser beam welding
KW - Numerical simulation
KW - Magnetohydrodynamic technology
KW - Porosity defect
KW - Keyhole
PY - 2024
UR - https://www.dvs-media.eu/de/neuerscheinungen/4671/44.-assistentenseminar-fuegetechnik
SN - 978-3-96144-267-6
VL - 394
SP - 77
EP - 86
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-60784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
T1 - Life cycle assessment of fusion welding processes strategies and implementation
N2 - In manufacturing, fusion welding processes use a lot of resources, which presents an opportunity to reduce environmental impact. While there is a general understanding of the environmental impact of these processes, it is difficult to quantitatively assess key parameters. This study introduces a welding-specific methodology that uses life cycle assessment (LCA) to evaluate the environmental impact of fusion welding technologies. Our approach analyses the main parameters that affect the environmental performance of different welding techniques, including traditional methods and additive manufacturing through the Direct Energy Deposition-Arc (DED-Arc) process. We integrate real-time resource usage data to offer an innovative framework for directly deriving environmental impacts. This research contributes to optimising welding processes by providing a precise and quantifiable measure of their ecological impact, facilitating the advancement of sustainable manufacturing practices.
T2 - CEMIVET - Circular Economy in Metal Industries
CY - Berlin, Germany
DA - 06.06.2023
KW - Life Cycle Assessment
KW - Fusion welding
KW - Additive manufacturing
KW - DED-Arc
PY - 2023
AN - OPUS4-59499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suarez Ocano, Patricia
T1 - Influence of heat-treatment-induced microstructural evolution on the Low Cycle Fatigue behavior of 316L stainless steel fabricated by Laser Powder Bed Fusion
N2 - Additive manufacturing, particularly the laser powder bed fusion (PBF-LB/M) process, has gained significant attention in recent years due to its ability to produce complex geometries with enhanced mechanical properties. Among the various materials used, 316L stainless steel is highly favored for cyclically loaded components due to its exceptional mechanical strength, high-temperature performance, and corrosion resistance, making it widely applicable across various industries. 316L SS fabricated by PBF-LB/M (PBF-LB/M/316L) exhibits a unique hierarchical microstructure, with high density of low-angle grain boundaries (LAGBs), nano-dispersed silicates, chemical micro-segregations, and solidification-induced cellular structures. Particularly, the submicron-sized cellular features enriched with chromium (Cr) and molybdenum (Mo), along with high dislocation densities, contribute to a superior strength-ductility balance compared to conventionally manufactured 316L SS. The dispersed silicate particles act also as a strengthening phase, impeding dislocation movement and enhancing plastic deformation resistance.
This study explores the effect of heat treatments on the low-cycle fatigue (LCF) behavior of PBF-LB/M/316L at room temperature (RT) and 600 °C. First, three heat treatment conditions were applied to the as-built material: 450 °C for 4 hours (HT450/4), 800 °C for 3 hours (HT800/3), and 900 °C for 1 hour (HT900/1) to investigate their influence on microstructural evolution. Microstructural analysis revealed that the HT450/4 condition preserved the cellular structure with high dislocation density, while the HT800/3 condition showed partial dissolution of cells together with reduction in segregated elements along the cell walls and a reduced dislocation density. The HT900/1 condition resulted in complete segregation and cellular structure dissolution with comparable dislocation density to HT800/3 while maintaining the crystallographic texture and grain morphology. Intermetallic χ phase was mostly observed at the grain boundaries in HT800/3, but not in HT900/1. Fully reversed LCF tests were conducted under strain-controlled conditions with a strain amplitude of 0.8 %. Tests were interrupted at specific intervals to analyze the interaction between hierarchical microstructural features and deformation mechanisms in the three heat-treated conditions. Due to the pronounced dislocation cell structures and elemental segregation, the microstructure of the HT450/4 condition significantly impact deformation and damage mechanisms during cyclic loading, which in turn, differ from the conventional produced counterparts. The results provide insights into the relationship between microstructural features and fatigue performance, highlighting key deformation and failure mechanisms under cyclic loading.
T2 - FEMS 2025 EUROMAT 18th European Congress and Exhibition on Advanced Materials and Processes
CY - Granada, Spain
DA - 14.09.2025
KW - Additive manufacturing
KW - 316L stainless steel
KW - Heat treatments
KW - Low Cycle Fatigue
KW - Microstructure
PY - 2025
AN - OPUS4-64238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Additive manufacturing for components in hydrogen technologies
N2 - With the introduction of a hydrogen-based energy and national economy, safety-relevant components for hydrogen technologies are becoming increasingly important. Characteristic of hydrogen technologies are, for example, harsh environmental conditions such as cryogenic or high-pressure storage, corrosion issues in fuel cells and electrolyzers, turbines, and many more. Additive manufacturing of components is becoming increasingly important and irreplaceable for the production of complex technical systems. Using the case studies of burners for gas turbines and electrodes and membranes for polymer (PEMFC) and solid oxide (SOFC) fuel cells, this article shows the potential of additive manufacturing of components. At the same time, however, the challenge of considering divergent mechanical properties depending on the direction of assembly in a "hydrogen-compatible" manner is also highlighted. Finally, the challenges posed by additive manufacturing and hydrogen for materials testing are highlighted under scenarios that are as realistic as possible.
T2 - MPA-Workshop Hydrogen
CY - Online meeting
DA - 10.11.2022
KW - Additive manufacturing
KW - Hydrogen
KW - Technologies
KW - Overview
KW - Component
PY - 2022
AN - OPUS4-56233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dittmann, Daniel
A1 - Saal, L.
A1 - Zietzschmann, F.
A1 - Mai, M.
A1 - Altmann, Korinna
A1 - Al-Sabbagh, Dominik
A1 - Ruhl, A. S.
A1 - Jekel, M.
A1 - Braun, U.
T1 - Aktivkohlecharakterisierung als weiterer Schlüssel für Adsorptionsprognosen organischer Spurenstoffe in der vierten Reinigungsstufe
N2 - In diesem Beitrag wird der Einfluss des Aktivkohleprodukts auf die Adsorption von Spurenstoffen aus Kläranlagenablauf gezeigt und diskutiert. Im zweiten Teil wird das Material Aktivkohle analytisch charakterisiert und die Eigenschaften systematisiert. Die gewonnenen Erkenntnisse werden mit Bezug zu Praxislösungen zusammengefasst.
T2 - Wasser 2021
CY - Online meeting
DA - 10.05.2021
KW - Aktivkohle
KW - Thermogravimetrie
KW - Zersetzungsgasanalyse
KW - Proximatanalyse
PY - 2021
SP - 373
EP - 378
AN - OPUS4-52740
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmann, Daniel
A1 - Eisentraut, Paul
A1 - Goedecke, Caroline
A1 - Wiesner, Yosri
A1 - Jekel, M
A1 - Ruhl, A S
A1 - Braun, Ulrike
T1 - Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine
N2 - The adsorption of organic micropollutants onto activated carbon is a favourable solution for the treatment of drinking water and wastewater. However, these adsorption processes are not sufficiently understood to allow for the appropriate prediction of removal processes. In this study, thermogravimetric analysis, alongside evolved gas analysis, is proposed for the characterisation of micropollutants adsorbed on activated carbon. Varying amounts of carbamazepine were adsorbed onto three different activated carbons, which were subsequently dried, and their thermal decomposition mechanisms examined. The discovery of 55 different pyrolysis products allowed differentiations to be made between specific adsorption sites and conditions. However, the same adsorption mechanisms were found for all samples, which were enhanced by inorganic constituents and oxygen containing surface groups. Furthermore, increasing the loadings led to the evolution of more hydrated decomposition products, whilst parts of the carbamazepine molecules were also integrated into the carbon structure. It was also found that the chemical composition, especially the degree of dehydration of the activated carbon, plays an important role in the adsorption of carbamazepine. Hence, it is thought that the adsorption sites may have a higher adsorption energy for specific adsorbates, when the activated carbon can then potentially increase its degree of graphitisation.
KW - Aktivkohle
KW - TED-GC/MS
KW - Adsorption
KW - Thermoanalytik
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506946
DO - https://doi.org/10.1038/s41598-020-63481-y
VL - 10
IS - 1
SP - 6695
PB - Nature Publishing Group
AN - OPUS4-50694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Usmani, Shirin M.
A1 - Plarre, Rüdiger
A1 - Hübert, Thomas
A1 - Kemnitz, E.
ED - Richter, K.
ED - Van de Kulien, J.-W.
T1 - Termite resistance of pine wood treated with nano metal fluorides
N2 - Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect wood from termite attack.
KW - Holzschutzmittel
KW - Nanoparticles
KW - Fluorides
KW - Termites
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514325
DO - https://doi.org/10.1007/s00107-020-01522-z
VL - 78
SP - 493
EP - 499
PB - Springer
CY - Berlin
AN - OPUS4-51432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chinellato, Fabio
A1 - Wilbig, Janka
A1 - Al-Sabbagh, Dominik
A1 - Colombo, P.
A1 - Günster, Jens
T1 - Gas flow assisted powder deposition for enhanced flowability of fine powders: 3D printing of alpha-tricalcium phosphate
N2 - The possibility of creating patient-specific individual implants makes Additive Manufacturing technologies of special interest for the medical sector. For substitution of bone defects, powder based Additive Manufacturing by Binder Jetting is a suitable method to produce complex scaffold-like structures made of bioceramics with easily adapted geometries and controlled porosity. The process inherent residual porosity in the printed part, even though desired as it supports bone ingrowth, also leads to limited mechanical strength. Currently, bioceramic scaffolds made by Binder Jetting feature suitable biocompatible and biodegradable properties, while a sufficient mechanical stability is rather challenging. The purpose of this work is to apply the gas flow assisted powder deposition introduced in 2014 by Zocca et al., to the powder bed during printing of bioceramic tablets and scaffolds using α-TCP powder as feedstock. This enables exploiting the advantages of an increased powder bed density, thereby improving the mechanical properties of the printed parts.
KW - Additive Manufacturing
KW - Binder Jetting
KW - Gas flow assisted powder deposition
KW - Alpha-tricalcium phosphate
KW - Scaffold
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510138
DO - https://doi.org/10.1016/j.oceram.2020.100003
SN - 2666-5395
VL - 1
SP - 100003
PB - Elsevier Ltd.
AN - OPUS4-51013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Getenet, M.
A1 - Otálora, F.
A1 - Emmerling, Franziska
A1 - Al-Sabbagh, Dominik
A1 - García-Ruiz, J. M.
T1 - Mineral precipitation and hydrochemical evolution through evaporitic processes in soda brines (East African Rift Valley)
N2 - Soda lakes of the East African Rift Valley are hyperalkaline, hypersaline lakes extremely enriched in Na+, K+, Cl−, CO32−, HCO3−, and SiO2. In this paper, we investigate the chemical evolution in these lakes and the production of chemical sediments by salt precipitation via evaporation. Water samples from tributary springs and three lakes (Magadi, Nasikie Engida and Natron) have been experimentally studied by in-situ X-ray diffraction during evaporation experiments to characterize the sequence of mineral precipitation. These data are complemented by ex-situ diffraction studies, chemical analyses and thermodynamic hydrochemical calculations producing detailed information on the activity of all solution species and the saturation state of all minerals potentially generated by the given composition. Major minerals precipitating from these samples are sodium carbonates/bicarbonates as well as halite. The CO3/HCO3 ratio, controlled by pH, is the main factor defining the Na‑carbonates precipitation sequence: in lake brines where CO3/HCO3 > 1, trona precipitates first whereas in hot springs, where CO3/HCO3 ≪ 1, nahcolite precipitates instead of trona, which forms later via partial dissolution of nahcolite. Precipitation of nahcolite is possible only at lower pH values (pCO2 higher than −2.7) explaining the distribution of trona and nahcolite in current lakes and the stratigraphic sequences. Later, during evaporation, thermonatrite precipitates, normally at the same time as halite, at a very high pH (>11.2) after significant depletion of HCO3− due to trona precipitation. The precipitation of these soluble minerals increases the pH of the brine and is the main factor contributing to the hyperalkaline and hypersaline character of the lakes. Villiaumite, sylvite, alkaline earth carbonates, fluorapatite and silica are also predicted to precipitate, but most of them have not been observed in evaporation experiments, either because of the small amount of precipitates produced, kinetic effects delaying the nucleation of some phases, or by biologically induced effects in the lake chemistry that are not considered in our calculations. Even in these cases, the chemical composition in the corresponding ions allows for discussion on their accumulation and the eventual precipitation of these phases. The coupling of in-situ and ex-situ experiments and geochemical modelling is key to understanding the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and other extraterrestrial bodies.
KW - Crystallization sequence
KW - Hydrochemical evolution
KW - Alkaline brines
KW - Sodium carbonate minerals
KW - Soda lakes
KW - Evaporite deposits
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568431
DO - https://doi.org/10.1016/j.chemgeo.2022.121222
SN - 0009-2541
VL - 616
SP - 1
EP - 13
PB - Elsevier
CY - New York, NY
AN - OPUS4-56843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Söftje, M.
A1 - Weingartz, T.
A1 - Plarre, Rüdiger
A1 - Gjikaj, M.
A1 - Namysko, J. C.
A1 - Kaufmann, D. E.
T1 - Surface Tuning of Wood via Covalent Modification of Its Lignocellulosic Biopolymers with Substituted BenzoatesA Study on Reactivity, Efficiency, and Durability
N2 - Chemical modification of wood applying benzotriazolyl-activated carboxylic acids has proven to be a versatile method for the durable functionalization of its lignocellulosic biopolymers. Through this process, the material properties of Wood can be influenced and specifically optimized. To check the scope and limitations of this modification method, various benzamide derivatives with electron-withdrawing (EWG) or electron-donating (EDG) functional groups in different positions of the aromatic ring were synthesized and applied for covalent modification of Scots pine (Pinus sylvestris L.) sapwood in this study. The bonded amounts of substances (up to 2.20 mmol) were compared with the reactivity constants of the Hammett equation, revealing a significant correlation between the modification efficiency and the theoretical reactivity constants of the corresponding aromatic substitution pattern. The successful covalent attachment of the respective substituted benzamides was proven by attenuated total reflection infrared (ATR-IR) spectroscopy, while the stability of the newly formed ester bond was proven in a standardized leaching test.
KW - Leaching
KW - Wood Protection
KW - Wood Modification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538932
DO - https://doi.org/10.1021/acsomega.1c04353
VL - 6
IS - 49
SP - 33542
EP - 33553
AN - OPUS4-53893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Röder, Bettina
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point.
Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools.
KW - Mechanochemistry
KW - Kinetics
KW - In situ
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558878
DO - https://doi.org/10.1039/d2fd00115b
SP - 1
EP - 16
PB - Royal Society of Chemistry
AN - OPUS4-55887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waniek, Tassilo
A1 - Braun, Ulrike
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
T1 - The impact of water released from boehmite nanoparticles during curing in epoxy-based nanocomposites
N2 - The enhancing effect on mechanical properties of boehmite (γ-AlOOH) nanoparticles (BNP) in epoxy-based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro- and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action.
With FTIR-spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail.
The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (Tg) and an interphase formation.
KW - Spectroscopy
KW - Aluminium oxide hydroxide
KW - Glass transition temperature
KW - Material chemistry
KW - Nanocomposites
KW - Structure-property relationship
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527202
DO - https://doi.org/10.1002/app.51006
VL - 138
IS - 39
SP - 51006
PB - Wiley Periodicals LLC
CY - Hoboken
AN - OPUS4-52720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - New developments in high power laser and hybrid welding of thick plates for application in modern ship building
N2 - High power laser beam welding has been already introduced in ship building industry since last two decades and is characterized by higher performance as conventional arc welding technologies through its higher welding speed, penetration depth and therefore higher productivity. Moreover, high quality weld joints are achievable thanks to a stronger automatization degree and better repeatability of the process. A further advantage of the laser beam welding is a manufacturing of parts with very low distortion according to much lower heat input, so that rework amount can be reduced significantly. Nevertheless, there are still some unresolved problems limiting the range of application of the technology in part manufacturing within ship building industry, restricted by development and application of new materials or new design of ship vessels.
The present contribution deals with some novel aspects of laser beam welding technology allowing to widen this range significantly. One of the possibilities is to increase the weld seam thickness for single pass laser or laser-hybrid welding is to apply contactless EM-support system based on generation of the Lorentz force counteracting the liquid metal drop out. Also, application of laser-hybrid welding technology for welding novel materials like cold resistant steel X8Ni9 used for construction of LNG tanks brings technological and design advantages comparing to conventional welding technologies by using of a similar alloyed filler wire instead of expensive Ni-based filler material. Finally, it is shown how the application of computational techniques can be used to helps to improve the quality of laser welded joints and avoid the critical weld failure by optimization of the welding process parameters.
T2 - SHY Virtual Laserforum 2020
CY - Online meeting
DA - 01.09.2020
KW - Ship building
KW - Laser beam welding
KW - Hybrid laser arc welding
PY - 2020
UR - https://laserforum.mobieforum.fi/
AN - OPUS4-51221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Medrano Sandonas, Leonardo
A1 - Balcells, David
A1 - Bochkarev, Anton
A1 - Cole, Jacqueline M.
A1 - Deringer, Volker L.
A1 - Dobrautz, Werner
A1 - Ehrenhofer, Adrian
A1 - Frank, Thorben
A1 - Friederich, Pascal
A1 - Friedrich, Rico
A1 - George, Janine
A1 - Ghiringhelli, Luca
A1 - Hinostroza Caldas, Alejandra
A1 - Juraskova, Veronika
A1 - Kneiding, Hannes
A1 - Lysogorskiy, Yury
A1 - Margraf, Johannes T.
A1 - Türk, Hanna
A1 - von Lilienfeld, Anatole
A1 - Todorović, Milica
A1 - Tkatchenko, Alexandre
A1 - Rossi, Mariana
A1 - Cuniberti, Gianaurelio
T1 - Perspective: Towards sustainable exploration of chemical spaces with machine learning
N2 - Artificial intelligence is transforming molecular and materials science, but its growing computational and data demands raise critical sustainability challenges. In this Perspective, we examine resource considerations across the AI-driven discovery pipeline--from quantum-mechanical (QM) data generation and model training to automated, self-driving research workflows--building on discussions from the ``SusML workshop: Towards sustainable exploration of chemical spaces with machine learning'' held in Dresden, Germany. In this context, the availability of large quantum datasets has enabled rigorous benchmarking and rapid methodological progress, while also incurring substantial energy and infrastructure costs. We highlight emerging strategies to enhance efficiency, including general-purpose machine learning (ML) models, multi-fidelity approaches, model distillation, and active learning. Moreover, incorporating physics-based constraints within hierarchical workflows, where fast ML surrogates are applied broadly and high-accuracy QM methods are used selectively, can further optimize resource use without compromising reliability. Equally important is bridging the gap between idealized computational predictions and real-world conditions by accounting for synthesizability and multi-objective design criteria, which is essential for practical impact. Finally, we argue that sustainable progress will rely on open data and models, reusable workflows, and domain-specific AI systems that maximize scientific value per unit of computation, enabling efficient and responsible discovery of technological materials and therapeutics.
KW - Materials acceleration platforms
KW - Autonomous and digitalized workflows
KW - Energy and functional materials design
KW - Physics‑informed and multi‑fidelity ML
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658911
DO - https://doi.org/10.48550/arXiv.2604.00069
SN - 2331-8422
SP - 1
EP - 44
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-65891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Moraes, M. C.
A1 - Durlo Tambara, Luís Urbano
A1 - Cheriaf, M.
A1 - Rocha, J. C.
T1 - The influence of relative humidity on drying shrinkage mechanisms in hybrid alkaline systems with bottom ash and rice husk ash
N2 - This study investigated the influence of relative humidity (RH = 30%, 60 %, and 90 %) on the drying shrinkage behaviour of hybrid alkaline cement (HAC) systems, composed of 30 % Portland cement and 70 % bottom ash (BA) and/or rice husk ash (RHA). At RH < 30 %, HAC mortars exhibited shrinkage strains up to 7 times higher than Portland cement, whereas curing at RH > 90 % reduced shrinkage by nearly 15-fold compared to dry conditions. The 70RHA mixture demonstrated the highest shrinkage under low RH, associated with its refined micropore structure and elevated internal surface area. Nitrogen adsorption-desorption analysis revealed that low RH hindered pore refinement, while wet curing promoted gel densification, increasing the fraction of pores below 5 nm and improving compressive strength. At intermediate RH, mesopore volume increased after 28 days, consistent with microstructural changes associated with moisture exchange processes. This work provides a combined analysis of humidity-dependent shrinkage mechanisms and pore structure evolution in hybrid alkaline systems incorporating industrial and agricultural residues. The main contribution lies in identifying two distinct shrinkage regimes governed by pore-scale mechanisms under different RH conditions, offering practical guidance for curing optimisation and dimensional stability control in sustainable cementitious materials.
KW - Alkali activation
KW - Hybrid alkaline cement
KW - Bottom ash
KW - Rice husk ash
KW - Drying shrinkage
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659064
DO - https://doi.org/10.1016/j.rineng.2026.110206
SN - 2590-1230
VL - 30
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65906
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Grandel, Jonas
A1 - Benner, Philipp
A1 - George, Janine
T1 - Parameter-efficient fine-tuning of machine-learning interatomic potentials for phonon and thermal properties
N2 - Machine-learning interatomic potentials are widely used as computationally efficient surrogates for density functional theory in atomistic simulations, enabling large-scale, long-time modeling of materials systems. We investigate how different fine-tuning strategies influence the prediction of harmonic phonon band structures, thermal properties, and the potential energy surface along imaginary phonon modes. We achieve substantial accuracy improvements with minimal additional data, with as few as 10 additional training structures already yielding significant gains. In addition to existing approaches, we introduce Equitrain, a finetuning framework that implements LoRA-based adaptation. Across 53 materials systems, we show that fine-tuned models consistently outperform both the underlying pretrained model and models trained from scratch. Equitrain achieves the best overall performance, and our results demonstrate that fine-tuning enables accurate phonon predictions.
KW - Phonons
KW - Thermodynamic properties
KW - Phase transitions
KW - Long-term stability
KW - Machine learning interatomic potentials
KW - Finetuning
KW - Automation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658932
DO - https://doi.org/10.48550/arXiv.2604.01017
SN - 2331-8422
SP - 1
EP - 32
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-65893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, Andreas
A1 - Buijsen, Paul
T1 - Poly(trimethylene terephthalate) − solid state polycondensation and the formation of monodisperse Extended-Ring crystals
N2 - Linear, low-molar-mass poly(trimethylene terephthalate) (PTT) was synthesized via the polycondensation of 1,3-propanediol and dimethyl terephthalate and investigated by matrix-assisted laser desorption/ionization time of flight (MALDI TOF) mass spectrometry, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and x-ray scattering. The obtained PTT was used in crystalline plaque or powder form for studies of its solid-state polycondensation (SSP). The combination of powder and vacuum increased the number-average molecular weight (Mn) by a factor of three. Interestingly, even-numbered cycles with degrees of polymerization (DPs) between six and 16 were preferentially formed. Annealing after doping with tin catalysts produced three cyclic main reaction products (C10, C12 and C14), which suggest that thermodynamic control of transesterification processes favors the formation of three types of monodisperse extended-ring crystallites (ERC) with thicknesses of 5, 6 of 7 repeat units. Additionally, a predominantly cyclic PTT was prepared, once again demonstrating the formation of even-numbered ERC upon annealing. Crystallinities calculated from WAXS measurements showed satisfactory agreement with those determined by DSC. SAXS measurements confirmed that the crystal thickness defined by ERC is also valid for long chains and large cycles that crystallize with chain folding.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Crystallisation
KW - Poly(trimethylene terephthalate)
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659071
DO - https://doi.org/10.1016/j.eurpolymj.2026.114716
SN - 0014-3057
VL - 252
SP - 1
EP - 10
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-65907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Schilling, Markus
A1 - Bayerlein, Bernd
A1 - Waitelonis, J.
A1 - Birkholz, H.
A1 - von Hartrott, P.
T1 - Tensile Test Ontology (TTO)
N2 - This is the tensile test ontology (TTO) in version 3.0.0 as developed on the basis of the tensile test standard ISO 6892-1:2019-11: Metallic materials - Tensile Testing - Part 1: Method of test at room temperature.
The TTO was developed in the frame of the project Plattform MaterialDigital (PMD). The TTO provides conceptualizations valid for the description of tensile tests and corresponding data in accordance with the respective test standard. By using TTO for storing tensile test data, all data will be well structured and based on a common vocabulary agreed upon by an expert group (generation of FAIR data) which will lead to enhanced data interoperability. Due to the import of the PMD core ontology (PMDco), here in version 3.0.0, the interoperability of tensile test data is enhanced and querying in combination with other aspects and data within the broad field of material science and engineering (MSE) is facilitated.
KW - Semantic Technology
KW - Knowledge Graph
KW - Tensile Test Ontology
KW - Ontology
KW - Machine-actionability
PY - 2026
UR - https://github.com/materialdigital/tensile-test-ontology/releases/tag/v3.0.0
UR - https://github.com/materialdigital/tensile-test-ontology
PB - GitHub
CY - San Francisco, CA, USA
AN - OPUS4-65909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation of the Extrapolation Capability of an Artificial Neural Network Algorithm in Combination with Process Signals in Resistance Spot Welding of Advanced High-Strength Steels
N2 - Resistance spot welding is an established joining process for the production of safetyrelevant components in the automotive industry. Therefore, consecutive process monitoring is essential to meet the high quality requirements. Artificial neural networks can be used to evaluate the process parameters and signals, to ensure individual spot weld quality. The predictive accuracy of such algorithms depends on the provided training data set, and the prediction of untrained data is challenging. The aim of this paper was to investigate the extrapolation capability of a multi-layer perceptron model. That means, the predictive performance of the model was tested with data that clearly differed from the training data in terms of material and coating composition. Therefore, three multi-layer perceptron regression models were implemented to predict the nugget diameter from process data. The three models were able to predict the training datasets very well. The models, which were provided with features from the dynamic resistance curve predicted the new dataset better than the model with only process parameters. This study shows the beneficial influence of process signals on the predictive accuracy and robustness of artificial neural network algorithms.
Especially, when predicting a data set from outside of the training space.
KW - Automotive
KW - Artificial intelligence
KW - Quality monitoring
KW - Resistance spot welding
KW - Quality assurance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539783
DO - https://doi.org/10.3390/met11111874
VL - 11
IS - 11
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-53978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Schmidt, Jonathan
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Olbricht, Jürgen
A1 - Jokisch, T.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation on seam quality and fatigue crack propagation in electron beam welded additive manufactured Inconel 939
N2 - Laser powder bed fusion of metals (PBF-LB/M) offers great potential for the production of new and spare parts for stationary gas turbines made of nickel superalloys such as Inconel 939 (IN939). In order to enable integration into existing assemblies and overcome design limitations, the additive manufacturing process chain must be expanded by suitable joining techniques. This study compares the electron beam welding of cast IN939 sheets and sheets produced additively using PBF-LB/M. The investigation focuses on the achievable seam quality with regard to geometric irregularities and internal defects in the form of liquation cracks on the microscale in the heat-affected zone. The evaluation of the welded samples shows no differences in the formation of the seam shape between the additively manufactured material and the cast material. For both materials, the highest quality category for beam-welded seams according to DIN EN ISO 13,919–1 was achieved at high welding speeds of 20 mm/s. Regardless of the manufacturing method, both materials show an increase in crack formation with increasing welding speed. However, due to its microstructure, the PBF-LB/M material exhibits significantly fewer microcracks overall. Final crack propagation tests on welded PBF-LB/M samples that were treated using HIP also show stable crack growth without sudden failure, which opens up potential for practical application.
KW - Electron beam welding
KW - Inconel 939
KW - PBF-LB/M
KW - Liquation cracking
KW - Fatigue crack propagation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657015
DO - https://doi.org/10.1016/j.jajp.2026.100389
SN - 2666-3309
VL - 13
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huo, Wenjie
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, Katinka
T1 - An illumination based backdoor attack against crack detection systems in laser beam welding
N2 - Deep neural networks (DNNs) have been wildly used in engineering and have achieved state-of-the-art performance in prediction and measurement tasks. A solidification crack is a serious fault during laser beam welding and it has been proven to be successfully detected using DNNs. Recently, research on the security of DNNs is receiving increasing attention because it is necessary to explore the reliability of DNNs to avoid potential security risks. The backdoor attack is a serious threat, where attackers aim to inject an inconspicuous pattern referred to as trigger into a small portion of training data, resulting in incorrect predictions in the reference phase whenever the input contains the trigger. In this work, we first generate experimental data containing actual cracks in the welding laboratory for training a crack detection model. Then, targeting this scenario, we design a new type of backdoor attack to induce the model to predict the crack as a normal state. Considering the stealthiness of the attack, a common phenomenon during the welding process, illumination, is used as the backdoor trigger. Experimental results demonstrate that the proposed method can successfully attack the crack detection system and achieve over 90% attack success rate on the test set.
T2 - 8th ML4CPS 2025 – Machine Learning for Cyber-Physical Systems
CY - Berlin, Germany
DA - 06.03,2025
KW - System security
KW - Welding crack detection
KW - Backdoor attack
KW - Deep neural networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651357
DO - https://doi.org/10.24405/20021
VL - 2025
SP - 12
EP - 21
PB - Universitätsbibliothek der HSU/UniBw H
CY - Hamburg
AN - OPUS4-65135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shakeel, Yusra
A1 - Ávila Calderón, Luis
T1 - Creating Exemplary RDM Reference Datasets: Technical Process Overview
N2 - The aim of the task area Materials Data Infrastructure (TA-MDI) of the consortium Materials Science and Engineering (MatWerk) of National Research Data Infrastructure (NFDI) is to shape scientific datasets obtained through the Participant Projects (PPs) from a data management perspective conforming to the FAIR principles, making use of the FAIR Digital Object (FAIR DO) concept, including structured metadata and storage solutions. As an example, they apply PP18 (BAM) as a use case to demonstrate the proposed technical workflow.
T2 - All-Hands-on-Deck congress from the NFDI-MatWerk
CY - Siegburg, Germany
DA - 08.03.2023
KW - NFDI
KW - Reference Dataset
KW - FAIR
KW - Research Data Management
PY - 2022
AN - OPUS4-57149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huo, Wenjie
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, Katinka
T1 - Prediction of mean strain from laser beam welding images and detection of defects via strain curves based on machine learning
N2 - With the advancement of machine learning, many predictions and measurements in visual tasks can be achieved by convolutional neural networks (CNNs). Solidification hot cracking is a significant defect in laser beam welding, commonly encountered in practical applications. Existing theories indicate that the formation of cracks is closely related to strain accumulation near the solidification front. In this paper, we first leverage supervised Regression networks to design CNNs that achieve real-time average strain estimation for each frame in the collected welding videos. Two different architectures are proposed and compared: the first model stacks two frames at a set interval and feeds them into the network, while the second model extracts image features individually and predicts the results by calculating the correlation between them. Each network has its own advantages in Terms of computational efficiency and accuracy. Finally, we further train a multilayer perceptron (MLP) classification model that can detect the occurrence of cracks based on the predicted strain behaviors.
KW - Laser beam welding
KW - Mean strain prediction
KW - Solidification cracking detection Convolutional neural networks
KW - Convolutional neural networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644495
DO - https://doi.org/10.1016/j.optlastec.2025.113975
SN - 0030-3992
VL - 192, Part F
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-64449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Arc-sidewall-attaching-driven control of swing arc motion in narrow gap GMAW
N2 - A novel, event-driven approach to controlling the weaving motion in swing arc narrow gap GMAW is presented in this study. The control method is based on independently detecting the arc attachment event at each sidewall of the narrow groove to adjust the weaving motion in real time. Previous arc sensing approaches for swing arc principles are based on evaluating and comparing arc sensor readings collected during the dwell periods at each sidewall. Not only does this require the torch to be positioned at the groove centre and the arc motion to be symmetric, but previous methods have also been shown to rely on complex parametrization of control parameters. The newly presented approach is based on the real-time monitoring of the welding current progression during the approach of the arc towards the sidewall of the groove independently on each side. As soon as the arc attachment at the sidewall is detected based on a characteristic rise in the current signal, the weaving motion is stopped. For reference experiments in a 21-mm wide groove, the weaving angle amplitude is controlled and limited to 50° on both sides individually, resulting in stable process conditions and uniform sidewall fusion. It is further shown that the newly developed control method can successfully be applied to groove widths of 18 mm and 24 mm without reconfiguration of the control parameters, highlighting the flexibility of the approach.
KW - Gas metal arc welding
KW - Narrow gap
KW - Arc sensor
KW - Control
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647640
DO - https://doi.org/10.1007/s40194-025-02238-5
SN - 0043-2288
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-64764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Kising, Pascal
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative artificial intelligence approach
N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A conditional variational autoencoder model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-variational autoencoder model with the evidence lower bound loss function and include Kullback–Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes.
KW - Laser beam welding
KW - Generative artificial intelligence
KW - Machine learning
KW - Numerical simulation
KW - Weld pool
KW - Keyhole dynamics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656621
DO - https://doi.org/10.2351/7.0001862
SN - 1042-346X
VL - 38
IS - 1
SP - 1
EP - 8
PB - Laser Institute of America
AN - OPUS4-65662
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Kaplan, Alexander
A1 - Rethmeier, Michael
T1 - Digitalisation and Carbon Footprint Evaluation of Gas Metal Arc Welding and Wire-Arc Directed Energy Deposition
N2 - This paper showcases how a holistic approach to digitalisation enables data-driven welding applications, exemplarily for a gas metal arc welding (GMAW) laboratory. The workflow integrates advanced process monitoring, synchronised multi-sensor data acquisition and tools for data analytics. A welding domain-specific data exchange format weldx is presented that unifies and aggregates the data sets acquired during process monitoring with final component quality metrics, supporting reuse, traceability, and reproducibility. Two case studies illustrate the approach. First, GMAW parameters are adaptively adjusted according to local seam geometry to compensate joint-preparation deviations from nominal values typical for large-scale steel fabrication. Second, the seamless data aggregation along the welding production chain enables an automatic life-cycle assessment (LCA), quantifying the environmental impacts of additive manufacturing with DED Arc/M and attributing the dominant contributors to the carbon footprint. Collectively, the results indicate that a fully integrated experimental set-up together with standardised data structures and scalable analytics can couple monitoring, control, and sustainability, thereby realising the potential of digitalisation for high-quality and environmentally informed welding production.
KW - Digitalisation
KW - Arc welding
KW - DED-arc
KW - Life Cycle Assessment
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656812
DO - https://doi.org/10.1088/1757-899X/1342/1/012067
SN - 1757-8981
VL - 1342
IS - 1
SP - 1
EP - 15
PB - IOP Publishing
AN - OPUS4-65681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
T1 - Experimental and numerical investigations of suppression mechanism of an oscillating magnetic field on process porosity during laser beam welding
N2 - Magnetohydrodynamic technology is increasingly recognized as a promising approach for enhancing the quality of deep penetration laser beam welding. This study employs experimental and numerical methods to investigate the effects of an auxiliary oscillating magnetic field on reducing porosity in the laser beam welding of 5754 aluminum alloy. The experimental results clearly demonstrate a significant reduction in the porosity ratio, thereby validating the efficacy of applying MHD technology in mitigating porosity during the laser beam welding process. In addition, a transient 3D multi-physical model has been developed, integrating the magnetohydrodynamic and metal vapor plume, to gain a more comprehensive understanding of the porosity suppression mechanism. The introduction of an oscillating magnetic field generates a time-averaged downward Lorentz force. This Lorentz force, in turn, induces an electromagnetic expulsive force, which effectively increases the upward escape velocity of bubbles in the molten pool. Furthermore, the molten pool shape is significantly enlarged, which further facilitate the escape of bubbles. The simulation results agree well with the experimental results.
T2 - Assistentenseminar der WGF (Wissenschaftliche Gesellschaft Fügetechnik e.V. im DVS)
CY - Päwesin, Germany
DA - 20.09.2023
KW - Deep penetration laser beam welding
KW - Oscillating magnetic field
KW - Numerical simulation
KW - Porosity
PY - 2023
AN - OPUS4-58796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sonntag, Nadja
T1 - Dwell-Fatigue and Cyclic Softening of Grade P92 Steel under LCF and TMF Conditions
N2 - Tempered martensite-ferritic steels, such as the grade P92 steel studied in this contribution, exhibit pronounced macroscopic cyclic softening under isothermal low-cycle fatigue (LCF) and non-isothermal thermomechanical fatigue (TMF) conditions, which is considered to be the predominant degradation mechanism in high-temperature fatigue in this and other material groups. However, such softening processes are highly complex since microscopic (e.g., recovery) and macroscopic (e.g., crack initiation and growth), as well as global and local effects superimpose, especially under creep-fatigue conditions. In this contribution, we discuss the cyclic deformation and softening behavior of P92 in strain-controlled LCF, in-phase (IP) TMF, and out-of-phase (OP) TMF tests with and without dwell times in the temperature range from 300 °C to 620°C. EBSD-based dislocation analysis on various fatigued material states confirms the continuous redistribution and annihilation of geometrically necessary dislocations in all studied states, which can be quantitatively correlated with macroscopic softening despite different damage mechanisms for different test types. Deviations from this correlation are observed for OP TMF and LCF with dwell times, i.e., for conditions where optical microscopy reveals pronounced crack-oxidation interactions at the specimen surfaces.
T2 - LCF9 - Ninth International Conference on Low Cycle Fatigue
CY - Berlin, Germany
DA - 21.06.2022
KW - LCF
KW - TMF
KW - EBSD
PY - 2022
DO - https://doi.org/10.48447/LCF9-2022-111
AN - OPUS4-55128
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Putra, Stephen Nugraha
T1 - Numerical study on the temperature characteristic of material absorptivity and its significance in high-power laser beam welding
N2 - The absorptivity of metallic materials plays an important role in high-power laser beam welding. It affects the amount of absorbed laser power leading to the heating and melting of the surfaces to be joined and is highly dependent on the temperature. Nonetheless, this key characteristic is often ignored in numerical simulations and an empirical parameter determined by trial-and-error approaches is rather implemented to calibrate the results. In the present work, the temperature dependence of laser absorption is included in a three-dimensional multiphase numerical model considering the coupled fluid flow and heat transfer. The calculated laser absorption is determined by the temperature-dependent material properties, laser characteristics, and incident angle of the laser beam. It is found that the temperature dependence of the laser absorption is crucial for accurately determining the keyhole and weld pool geometries, which is validated by experimental measurements using 304 austenitic steel.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Temperature dependent absorption
KW - Weld pool
KW - Keyhole dynamics
KW - Numerical modelling
PY - 2024
AN - OPUS4-61612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - A statistical assessment of the laser energy absorption and keyhole stability in high-power laser welding
N2 - The behavior of the molten pool and final weld qualities in high-power laser welding are significantly influenced by laser absorption and keyhole stability. However, the dynamic features involved make the in-depth analyses challenging. This study addresses the challenges by conducting a thorough statistical evaluation of the effects of key welding parameters on laser absorption and keyhole fluctuations, using experimental investigations and a robustly validated multi-physics model. From a statistical aspect, the laser energy distribution and the keyhole collapse, commonly considered to be highly time-varying, show certain regularities, for example, three distinct regions of the temporally averaged energy distribution and a universal normal distribution of the keyhole collapse positions. Further discussion is performed to clarify the greater potential of the statistical data in revealing some well-known, industry-related but unclearly explained findings, such as the saturation of the weld penetration with increasing heat input and the physical basis of the contributions of different welding parameters in the porosity reduction.
KW - Laser welding
KW - Laser absorption
KW - Keyhole stability
KW - Porosity defect
KW - Multi-physics modeling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628367
DO - https://doi.org/10.1016/j.jmapro.2025.03.053
SN - 2212-4616
VL - 141
SP - 885
EP - 896
AN - OPUS4-62836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Experimental and numerical study on grain refinement in electromagnetic assisted laser beam welding of 5754 Al alloy
N2 - Through experimental observation and auxiliary numerical simulation, this investigation studies the different types of grain refinement of 5754 aluminum alloy laser beam welding by applying a transverse oscillating magnetic field. Scanning electron microscope results have proved that the application of a magnetic field can reduce the average crystal branch width and increase its number. The interaction between the induced eddy current generated by the Seebeck effect and the applied external magnetic field produces a Lorentz force, which is important for the increase in the number of crystal branches. Based on the theory of dendrite fragmentation and the magnetic field-induced branches increment, the grain size reduction caused by the magnetic field is studied. Furthermore, the effects of the magnetic field are analyzed by combining a phase field method model and simulations of nucleation and grain growth. The grain distribution and average grain
size after welding verify the reliability of the model. In addition, the introduction of a magnetic field can increase the number of periodic three-dimensional solidification patterns. In the intersection of two periods of solidification patterns, the metal can be re-melted and then re-solidified, which prevents the grains, that have been solidified and formed previously, from further growth and generates some small cellular grains in the new fusion line. The magnetic field increases the building frequency of these solidification structures and thus promotes this kind of grain refinement.
KW - Laser beam welding
KW - Magnetic field
KW - Crystal branch development
KW - Grain refinement
KW - Periodic solidification pattern
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584905
DO - https://doi.org/10.2351/7.0001085
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
PB - AIP Publishing
AN - OPUS4-58490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - The influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling
N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a ray-tracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized Level-Set method. The PLIC-based method is discrete, resulting in non-continuous free surface reconstruction. In the localized Level-Set method, a continuous free surface is reconstructed, and thus the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics.
T2 - The 41st annual International Congress on Applications of Lasers & Electro-Optics
CY - Orlando, FL, USA
DA - 17.10.2022
KW - Laser beam welding
KW - Laser energy distribution
KW - Weld pool dynamics
KW - Ray-tracing
PY - 2022
AN - OPUS4-56312
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Challenges in dynamic heat source modeling in high-power laser beam welding
N2 - The amount of absorbed energy in the keyhole as well as its spatial and temporal distribution is essential to model the laser beam welding process. The recoil pressure, which develops because of the evaporation process induced by the absorbed laser energy at the keyhole wall, is a key determining factor for the macroscopic flow of the molten metal in the weld pool during high-power laser beam welding. Consequently, a realistic implementation of the effect of laser radiation on the weld metal is crucial to obtain reliable and accurate simulation results. In this paper, we discuss manyfold different improvements on the laser-material interaction, namely, the ray tracing method, in the numerical simulation of the laser beam welding process. The first improvement relates to locating the exact reflection points in the ray tracing method using a so-called cosine condition in the determination algorithm for the intersection of reflected rays and the keyhole surface. A second correction refers to the numerical treatment of the Gaussian distribution of the laser beam, whose beam width is defined by a decay of the laser intensity by a factor of 1/e2, thus ignoring around 14% of the total laser beam energy. In the third step, the changes in the laser radiation distribution in the vertical direction were adapted by using different approximations for the converging and the diverging regions of the laser beam, thus mimicking the beam caustic. Finally, a virtual mesh refinement was adopted in the ray tracing routine. The obtained numerical results were validated with experimental measurements.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, Illinois, USA
DA - 16.10.2023
KW - Laser beam welding
KW - Laser energy distribution
KW - Ray tracing
KW - Numerical modeling
PY - 2023
AN - OPUS4-58759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative approach
N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A Conditional Variational Autoencoder (CVAE) model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-VAE model with the Evidence Lower Bound (ELBO) loss function and include Kullback-Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes.
T2 - The 45th annual International Congress on Applications of Lasers & Electro-Optics
CY - Orlando, FL, USA
DA - 12.10.2025
KW - Laser beam welding
KW - Generative artificial intelligence
KW - Machine Learning
KW - Numerical Simulation
KW - Weld pool
KW - Keyhole dynamics
PY - 2025
AN - OPUS4-64812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
ED - Schmidt, M.
ED - Vollertsen, F.
ED - Govekar, E.
T1 - LMD coatings as filler material for laser beam welded 30 mm thick plates
N2 - The development of high energy laser sources enables single-pass welds of thick plates up to 30 mm, but often additional materials are needed to influence the properties of the weld seams. However, the homogenous distribution of filler materials in form of e.g. electrodes is only possible up to 7 mm while the elements are only traceable up to a depth of 14 mm. To overcome this problem a two-step process is used where first the edges of the weld partners are coated with the filler material by laser metal deposition (LMD) and afterwards are welded by laser beam. Single-pass welds with electromagnetic weld pool support of 30 mm thick S355 J2+N-plates with austenitic AISI 316L-coatings were investigated as well as the influence of the coatings to the penetration depth of the laser beam without electromagnetic weld pool support in double-sided joints. The weld seams were tested by X-ray inspection and cross sections.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
CY - Online meeting
DA - 07.09.2020
KW - Penetration depth
KW - Laser metal deposition (LMD)
KW - Laser beam welding
KW - Filler material distribution
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512790
DO - https://doi.org/10.1016/j.procir.2020.09.055
SN - 2212-8271
VL - 94
SP - 293
EP - 297
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-51279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
ED - Schmidt, M.
ED - Vollertsen, F.
ED - Schmidt, B. M.
T1 - Preliminary study to investigate the applicability of optical strain measurement technique for the detection of hot cracks in laser metal deposited layers
N2 - Laser metal deposition (LMD) as an additive manufacturing technique became increasingly important in recent years and thus the demand for component safety. This is the reason, for the need for reliable in-situ defect detection techniques. For laser beam weld seams an optical measurement technique based on an optical flow algorithm was successfully used to define the critical straining conditions that lead to hot cracking. This algorithm was adapted for bead-on-plate weld seams on LMD deposited layers of IN718 alloy while performing external strain on the specimen in an externally loaded hot cacking test facility. The resulting transversal hot cracks along the weld seam were localized via X-Ray inspection and the type of cracking confirmed by Scanning Electron Microscopy (SEM). The strain distribution was measured in the vicinity of the solidification front and correlated to the detected hot cracks. Based on the results this technique could be adopted for LMD experiments.
T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser Metal Deposition (LMD)
KW - Strain measurement
KW - Optical flow
KW - Critical strain
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556445
DO - https://doi.org/10.1016/j.procir.2022.08.034
VL - 111
SP - 335
EP - 339
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-55644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Elektromagnetische Schmelzbadbeeinflussung beim Laserhybridschweißen von Dickblechen
N2 - Die technischen Entwicklungen in der Lasertechnologie in den letzten Jahrzehnten haben eine neue Generation von Hochleistungslasersystemen im Leistungsbereich bis zu 100 kW auf den Markt gebracht. Dennoch ist die industrielle Anwendung des Hochleistungslaserstrahlschweißens auf bis zu 15 mm dicke Bleche beschränkt. Mögliche Ursachen der Einschränkungen des Verfahrens sind z.B. die Sensibilität des Verfahrens auf Fertigungstoleranzen wie Spalt und Kantenversatz, die erhöhte Tropfenbildung bei höheren Blechdicken und eine inhomogene Verteilung des Zusatzwerkstoffes beim Laserhybridschweißen. In dieser Studie wird ein auf extern angelegte Magnetfelder basierte elektromagnetische Schmelzbadstütze eingesetzt, um die Grenzen des Verfahrens zu erweitern und die Herausforderungen zu minimieren. Der wesentliche Vorteil der elektromagnetischen Schmelzbadstütze ist, dass sie berührungslos arbeitet. Mit Hilfe der elektromagnetischen Schmelzbadstütze konnten bei 20 mm dicken Proben aus S355J2 die Tropfenbildung an der Wurzel vermieden werden. Zudem wurde der Einfluss der Kantenqualität auf die Schweißnahtqualität untersucht, wobei verschiedene Schneidverfahren zur Kantenvorbereitung eingesetzt wurden, wie z.B. Plasma-, Brenn- oder Laserschneiden. Es konnte gezeigt werden, dass auch bei schlechteren Kantenvorbereitung im Gegensatz zu gefrästen Bauteilen die Werkstoffe einlagig mittels Laserhybridschweißen bei einer hohen Schweißnahtqualität gefügt werden konnten. Bei plasmageschnittenen Proben wurden zudem eine Spaltüberbrückbarkeit bzw. Kantenversatz von bis zu 2 mm sicher überbrückt. Des Weiteren war es mit Hilfe der externen Magnetfelder möglich, die Durchmischung des Zusatzwerkstoffes über die gesamte Schweißnahttiefe deutlich zu homogenisieren.
T2 - 42. Assistentenseminar der Wissenschaftlichen Gesellschaft Fügetechnik e.V.
CY - Blankenau, Germany
DA - 06.10.2021
KW - Elektromagnetische Schmelzbadstütze
KW - Laserhybridschweißen
KW - Dickblech
PY - 2022
VL - 385
SP - 1
EP - 7
PB - DVS Media GmbH
AN - OPUS4-56375
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
A1 - Meng, Xiangmeng
T1 - Project title: Multi-physical simulation of the influence of an auxiliary magnetic field on the process porosity formation during high-power laser beam welding
N2 - In this project, a multiphysically coupled numerical model will be developed to quantitatively describe porosity reduction in high-power laser beam welding of up to 10 mm thick AlMg3 using an oscillating magnetic field. The aim is to gain fundamental insights into the physical dependencies of the introduced electromagnetic forces on the melt pool behavior and the reduction of porosity. With the help of the numerical model, the transient, multi-coupled, three-dimensional problem of heat transfer, liquid flow, free surface deformation, and magnetic induction is to be solved, taking into account temperature-dependent material properties. The numerical modelling of the heat source will integrate all relevant physical mechanisms, for instance, multiple reflections of the laser radiation by an advanced ray tracing model, as well as local Fresnel absorption at the keyhole wall. This allows an analysis of the keyhole fluctuations, which have a dominant influence on the formation of process spores during deep penetration welding, based on physical principles. In addition, further physical factors such as the ablation pressure of the evaporating metal, the Laplace pressure, and Marangoni shear stresses are also to be integrated into the model. To evaluate the pore formation and reduction by means of the electromagnetic forces introduced in the molten pool, suitable models for describing the movement of the pores in the melt are to be developed. For the process pores, their movement can be implemented by tracking their surface under consideration of their internal pressure and temperature. With the help of the simulation model, all key factors for the formation of process pores during laser beam welding of the used aluminum alloy, as well as their avoidance, can be decoupled and analyzed. Accompanying welding tests are planned at BAM on a 20 kW fiber laser and a 16 kW disk laser. The magnetic flux density will be up to 500 mT at a maximum frequency of 5 kHz. The experimental results, in particular temperature measurements, weld cross sections, computer tomography, and X-ray examinations, will be used to verify the multiphysical model and its calibration. Moreover, the models will be validated and quantified by in situ high-speed imaging of the keyhole dynamics in a metal/quartz glass configuration with keyhole illumination by a diode laser coaxial to the processing laser. On the basis of the numerical and experimental results, the dependencies between applied magnetic field, melt pool behavior, and porosity formation will be revealed in this project.
KW - Laser beam welding
KW - Electromagnetic weld pool control
KW - Numerical simulation
KW - Process porosity
PY - 2026
DO - https://doi.org/10.34657/27669
SP - 1
EP - 14
AN - OPUS4-65335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Parametric study of the laser energy absorption in high-power laser beam welding
N2 - Laser energy absorption on the keyhole wall is decisive for the thermodynamic behavior and the resultant weld properties in the high-power laser beam welding process. However, its highly transient nature on a microsecond scale makes the quantitative analysis challenging. In this paper, the influence of the relevant welding parameters on laser energy absorption is studied statistically by utilizing multiphysical modeling, in which the three-dimensional transient keyhole dynamics and thermo-fluid flow are calculated. A dynamic mesh adaption technique and a localized level-set-based ray-tracing method are employed to improve the model accuracy further. The results show that the focus position has a remarkable effect on the time-averaged laser absorption, and in contrast, the laser energy distribution regime is only slightly influenced by the welding speed in the studied parameter range (1.5–3.0 m/min). The absorption ratio of the laser energy on the keyhole front wall decreases with increasing welding speed and increases with upward-moving focus positions. The comparison between the calculated results and the experimental measurements ensures the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 03.11.2024
KW - Laser beam welding
KW - Laser energy absorption
KW - Multiphysics modeling
KW - Parametric study
KW - Weld pool
PY - 2024
SP - 1
EP - 8
AN - OPUS4-61629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hickel, Tilmann
A1 - Waske, Anja
A1 - Tehranchi, Ali
A1 - Bhattacharya, Biswajit
A1 - Stawski, Tomasz M.
A1 - Fellinger, Tim-Patrick
A1 - Mehmood, Asad
A1 - Witt, Julia
A1 - Ozcan, Ozlem
A1 - Guilherme Buzanich, Ana
A1 - Kumar, Sourabh
A1 - Mishra, Rajesh Kumar
A1 - Holzer, Marco
A1 - Stucchi de Camargo, Andrea Simone
A1 - Agudo Jácome, Leonardo
A1 - Manzoni, Anna
A1 - Fantin, Andrea
A1 - John, Elisabeth
A1 - Hodoroaba, Vasile-Dan
A1 - Bührig, Sophia
A1 - Murugan, Jegatheesan
A1 - Marschall, Niklas
A1 - George, Janine
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
A1 - Emmerling, Franziska
T1 - Chemically complex materials enable sustainable high-performance materials
N2 - Chemically complex materials (CCMats) including high-entropy alloys, oxides, and related multi-principal element systems offer a paradigm shift in materials design by leveraging chemical diversity to simultaneously optimize functional, structural, and sustainability criteria. The vastness of the compositional and structural space in CCMats propels the field into an expanding exploratory state. To reconcile functional and structural performance across this immense parameter space remains an open challenge. This Perspective evaluates the opportunities and challenges associated with harnessing chemical complexity across a broad spectrum of applications, such as hydrogen storage, ionic conductors, catalysis, magnetics, dielectrics, semiconductors, optical materials, and multifunctional structural systems. It is delineated how three central design strategies: targeted substitution (SUB), defect engineering (DEF), and diversity management (DIV) enable the reconciliation of high functional performance with long-term structural stability and environmental responsibility.
Advances in computational thermodynamics, microstructure simulations, machine learning, and multimodal characterization are accelerating the exploration and optimization of CCMats, while robust data infrastructures and automated synthesis workflows are emerging as essential tools for navigating their complex compositional space. By fostering cross-disciplinary knowledge transfer and embracing data-driven design, CCMats are poised to deliver next-generation materials solutions that address urgent technological, energy, and
environmental demands.
KW - Chemically complex materials
KW - Structural stability
KW - Functional performance
KW - Design strategies
KW - Sustainability
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655598
UR - https://www.sciencedirect.com/science/article/pii/S1359028626000033?via%3Dihub
DO - https://doi.org/10.1016/j.cossms.2026.101256
SN - 1359-0286
VL - 42
SP - 1
EP - 26
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-65559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bustamante, Joana
A1 - Ghata, Anupama
A1 - Naik, Aakash A.
A1 - Ertural, Christina
A1 - Ueltzen, Katharina
A1 - Zeier, Wolfgang G.
A1 - George, Janine
T1 - Thermal transport in Ag8T S6(T = Si, Ge, Sn) argyrodites: an integrated experimental, quantum-chemical, and computational modelling study
N2 - Argyrodite-type Ag-based sulfides combine exceptionally low lattice thermal and high ionic conductivity, making them promising candidates for thermoelectric and solid-state energy applications. In this work, we studied Ag8TS6 (T = Si, Ge, Sn) argyrodite family by combining chemical-bonding analysis, lattice vibrational properties simulation, and experimental measurements to investigate their structural and thermal transport properties. Furthermore, we propose a two-channel lattice-dynamics model based on Grüneisen-derived phonon lifetimes and compare it to an approach using machine-learned interatomic potentials. Both approaches are able to predict thermal conductivity in agreement with experimental lattice thermal conductivities along the whole temperature range, highlighting their potential suitability for future high-throughput predictions. Our findings also reveal a relationship between bond heterogeneity arising from weakly bonded Ag+ ions and occupied antibonding states in Ag–S and Ag–Ag interactions and strong anharmonicity, including large Grüneisen parameters, and low sound velocities, which are responsible for the low lattice thermal conductivity of Ag8SnS6, Ag8GeS6, and Ag8SiS6. We furthermore show that thermal and ionic conductivities in all three compounds are independent of each other and can likely be tuned individually.
KW - Thermal Conductivity
KW - Ionic Conductivity
KW - Machine Learning
KW - Materials Design
KW - Microstructure
KW - Bonding Analysis
KW - Anharmonicity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657076
DO - https://doi.org/10.1039/D5TA08709K
SN - 2050-7488
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Naik, Aakash A.
A1 - Dhamrait, Nidal
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - Benner, Philipp
A1 - Rignanese, Gian-Marco
A1 - George, Janine
T1 - A critical assessment of bonding descriptors for predicting materials properties
N2 - Most machine learning models for materials science rely on descriptors based on materials compositions and structures, even though the chemical bond has been proven to be a valuable concept for predicting materials properties. Over the years, various theoretical frameworks have been developed to characterize bonding in solid-state materials. However, integrating bonding information from these frameworks into machine learning pipelines at scale has been limited by the lack of a systematically generated and validated database. Recent advances in high-throughput bonding analysis workflows have addressed this issue, and our previously computed Quantum-Chemical Bonding Database for Solid-State Materials was extended to include approximately 13,000 materials. This database is then used to derive a new set of quantum-chemical bonding descriptors. A systematic assessment is performed using statistical significance tests to evaluate how the inclusion of these descriptors influences the performance of machine-learning models that otherwise rely solely on structure- and composition-derived features. Models are built to predict elastic, vibrational, and thermodynamic properties typically associated with chemical bonding in materials. The results demonstrate that incorporating quantum-chemical bonding descriptors not only improves predictive performance but also helps identify intuitive expressions for
properties such as the projected force constant and lattice thermal conductivity via symbolic regression.
KW - Bonding Analysis
KW - Machine Learning
KW - Symbolic Regression
KW - Chemical Understanding
KW - Phonons
KW - Thermal Conductivity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655150
DO - https://doi.org/10.48550/arXiv.2602.12109
SP - 1
EP - 28
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-65515
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yuanbin
A1 - Zhou, Yuxing
A1 - Ademuwagun, Richard
A1 - Walterbos, Luc
A1 - George, Janine
A1 - Elliott, Stephen R.
A1 - Deringer, Volker L.
T1 - Medium-Range Structural Order in Amorphous Arsenic
N2 - Medium-range order (MRO) is a key structural feature of amorphous materials, but its origin and nature remain elusive. Here, we reveal the MRO in amorphous arsenic (a-As) using advanced atomistic simulations, based on machine-learned potentials derived using automated workflows. Our simulations accurately reproduce the experimental structure factor of a-As, especially the first sharp diffraction peak (FSDP), which is a signature of MRO. We compare and contrast the structure of a-As with that of its lighter homologue, red amorphous phosphorus (a-P): we find that a-As has a more uniform dihedral-angle distribution, and so we confirm that its structure can be thought of as a 3-fold coordinated continuous random network in first approximation, in contrast to the more molecular-cluster-like structure of a-P. The pressure-dependent structural behaviors of a-As and a-P differ as well, and the origin of the FSDP is closely correlated with the size and spatial distribution of voids in the amorphous networks. Our work provides fundamental insights into MRO in an amorphous elemental system, and more widely it illustrates the usefulness of automation for machine-learning-driven atomistic simulations.
KW - Machine Learned Interatomic Potentials
KW - Amorphous
KW - Advanced Materials
KW - Automation
KW - Digitalisation
KW - Structure-Property- Relationships
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655952
DO - https://doi.org/10.1021/jacs.5c18688
SN - 0002-7863
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-65595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, Raphael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Influence of laser power on the melt pool shape of handheld laser beam welding of 1.5 mm thick micro alloyed steel
N2 - Manual welding of structures requires highly skilled welders due to the large heat-affected zone of arc-based processes, that can negatively impact microstructure and cause distortion. Handheld laser beam welding is a promising alternative with high welding velocity and a concentrated heat input. However, its current use in industry is limited to parts with aesthetic requirements, often made of high-alloyed steel. To extend the use of handheld laser beam welding to low-cost steels with good mechanical properties, this study investigates the influence of laser power on the melt pool shape for micro-alloyed steel with a thickness of 1.5 mm. Tested joint geometries are T-joints welded with filler wire as well as butt joints and overlap joints without filler wire, which are typically found in assemblies under mechanical load. Weld quality is assessed by weld porosity analysis. The results show that the handheld laser beam welding with filler wire produces T-joints with a very good external appearance, but with porosity between level C and D in the cross sections according to DIN EN ISO 13919-1. By increasing the laser power, a deep penetration of the T-joint zone can be achieved without increasing the actual throat thickness. For handheld laser beam welding of butt joints a full penetration weld of the highest quality class can be reached. Overlap joints can be welded with full or partial penetration depending on the laser power selected, with quality classes between B and C in terms of porosity.
T2 - 20th Nordic Laser Materials Processing Conference
CY - Kongens Lyngby, Denmark
DA - 26.08.2025
KW - Hand held laser welding
KW - Laser beam welding
KW - Low alloyed steel
KW - Process parameter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641671
DO - https://doi.org/10.1088/1757-899X/1332/1/012015
SN - 1757-899X
VL - 1332
SP - 1
EP - 6
PB - Institute of Physics
CY - London [u.a.]
AN - OPUS4-64167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
A1 - Ouellet-Plamondon, Claudiane
A1 - Reyes, Kristofer
T1 - Introduction to the “Accelerate Conference 2023–2024” themed collection
N2 - The collection showcases the ways in which automation, machine learning and robotics are transforming experimental materials science and chemistry into continuous, computationally integrated processes. It features innovations regarding autonomous laboratories, Bayesian optimisation, high-throughput experimentation and computation, and AI-driven literature extraction, which simplify and scale up materials discovery. Together, these works outline a modular, responsible framework for accelerating scientific progress through human-guided, data-driven autonomy.
KW - Automation
KW - Materials Acceleration Platforms
KW - Synthesizability
KW - Workflows
KW - Large Language Models
KW - Ontologies
KW - Materials Discovery
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654658
DO - https://doi.org/10.1039/d5dd90057c
SN - 2635-098X
SP - 1
EP - 2
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmann, Daniel
A1 - Lucke, T.
A1 - Ruhl, A. S.
A1 - Winzenbacher, R.
A1 - Jekel, M.
A1 - Braun, Ulrike
T1 - Untersuchungen zu biologischen, organischen und anorganischen Veränderungen granulierter Aktivkohlen während der Trinkwasseraufbereitung
N2 - Untersuchungen zu biologischen, organischen und anorganischen Veränderungen granulierter Aktivkohlen während der Trinkwasseraufbereitung des Landeswasserversorgers Langenau.
KW - Thermogravimetrie
KW - Trinkwasser
KW - Wasseraufbereitung
KW - Aktivkohle
PY - 2020
SN - 0083-6915
VL - 118
IS - 2
SP - 47
EP - 50
PB - Wiley-VCH Verlag GmbH & Co. KGaA
AN - OPUS4-51434
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - Pauw, Brian Richard
T1 - "Ultima Ratio": Multi-scale, high-resolution 3D-FFT scattering pattern simulations
N2 - This talk highlights a proof-of-concept that demonstrates the ability to calculate high-resolution Fourier transforms. These can be combined with multi-scale modeling to simulate scattering over a wide range, from small-angle scattering to XRD and PDF.
The preprint documenting this is available on the ArXiv here:
https://doi.org/10.48550/arXiv.2303.13435
The Jupyter notebook, VASP calculation details and MOUSE measured scattering patterns are available from this Zenodo repository: https://dx.doi.org/10.5281/zenodo.7764045
T2 - Shapespyer/MuSSIC Launch Workshop
CY - Didcot, UK
DA - 20.02.2023
KW - Video
KW - Simulation
KW - High-resolution
KW - Fourier Transform
KW - 3D FFT
KW - Nanomaterial
KW - Metal organic framework
KW - MOF
KW - SAXS
KW - XRD
KW - PDF
KW - X-ray diffraction
KW - Pair distribution function
KW - Small-angle X-ray scattering
PY - 2023
UR - https://www.youtube.com/watch?v=lEApkOqR5e8
DO - https://doi.org/10.26272/opus4-57212
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-57212
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
A1 - Petretto, G.
A1 - Naik, Aakash
A1 - Esters, M.
A1 - Jackson, A. J.
A1 - Nelson, R.
A1 - Dronskowski, R.
A1 - Rignanese, G.-M.
A1 - Hautier, G.
T1 - Automated bonding analysis with crystal orbital Hamilton populations (program code LobsterPy)
N2 - This is the code for the program LobsterPy that can be used to automatically analyze and plot outputs of the program Lobster.
KW - Automation
KW - High-throughput computations
KW - Bonding analysis
PY - 2022
UR - https://doi.org/10.5281/zenodo.6320074
UR - https://doi.org/10.5281/zenodo.6415169
UR - https://doi.org/10.5281/zenodo.6415336
UR - https://doi.org/10.5281/zenodo.6581118
UR - https://doi.org/10.5281/zenodo.15034145
DO - https://doi.org/10.5281/zenodo.6320073
PB - Zenodo
CY - Geneva
AN - OPUS4-55174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Karkhin, V.
A1 - Bakir, Nasim
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Lamé curve approximation for the assessment of the 3D temperature distribution in keyhole mode welding processes
N2 - A novel approach for the reconstruction of an equivalent volumetric heat source from a known weld pool shape is proposed. It is based on previously obtained weld pool geometries from a steady-state thermo-fluid dynamics simulation. Hereby, the weld pool dimensions are obtained under consideration of the most crucial physical phenomena, such as phase transformations, thermo-capillary convection, natural convection, and temperature-dependent material properties. The algorithm provides a time and calibration efficient way for the reproduction of the weld pool shape by local Lamé curves. By adjusting their parameters, the identification of the finite elements located within the weld pool is enabled. The heat input due to the equivalent heat source is assured by replacing the detected nodes’ temperature by the melting temperature. The model offers variable parameters making it flexible and adaptable for a wide range of workpiece thicknesses and materials and allows for the investigation of transient thermal effects, e.g., the cooling stage of the workpiece. The calculation times remain acceptably short especially when compared to a fully coupled process simulation. The computational results are in good agreement with performed complete-penetration laser beam welding experiments.
KW - Lamé curves approximation
KW - Equivalent heat source
KW - Thermal cycles
KW - Numerical modeling
KW - Keyhole mode welding
PY - 2020
DO - https://doi.org/10.2351/7.0000076
VL - 32
IS - 2
SP - 022042-1
EP - 022042-8
PB - AIP Publishing
AN - OPUS4-50768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash
T1 - Material property predictions by incorporating quantum chemical bonding information
N2 - Interactions between constituent atoms in crystalline materials have been shown to influence the properties of materials, such as elasticity, ionic and thermal conductivity, etc.[1–3] These interactions between constituent atoms, often quantified as bond strengths, can be extracted from crystalline materials using density-based[4], energy-based[5], and orbital-based methods. LOBSTER[6] is a software that relies on the orbital-based method to extract such bonding information by projecting the plane wave-based wave functions of modern density functional theory computations (DFT) onto a local atomic orbital basis. To garner a better understanding of how this bonding information relates to material properties on a larger scale, machine learning seems an obvious choice. However, for such data-driven studies, large quantities of data that are systematically generated, validated, and post-processed (feature engineering) in a form suitable for input in state-of-the-art ML models are often needed.[7] Here, we first present a workflow implemented in atomate2[8] that can generate such bonding-related data using the LOBSTER program with minimal user input and a post-processing tool, LobsterPy[9], which can summarize and engineer features that could be directly used as input for ML studies. Lastly, we demonstrate the utility of these newly generated features by building a simple machine-learned model to predict harmonic phonon properties using the bonding dataset[10] generated by us for 1500 materials. We find a clear correlation between the bonding information and the phonon property.
T2 - STC 2024
CY - Braunschweig, Germany
DA - 02.09.2024
KW - Bonding analysis
KW - Machine learning
KW - Feature engineering
PY - 2024
AN - OPUS4-61130
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Thermal Cycles and Charpy Impact Toughness of Single-Pass Hybrid Laser-Arc Welded Thick-Walled Structures
N2 - The study deals with the influence of the heat input on the thermal cycles and Charpy impact toughness for hybrid laser-arc welding of 25 mm thick structural steel S355J2 using a 20-kW high-power laser in combination with an electromagnetic weld pool support. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured using a pyrometer in combination with an optical fibre in three different locations near to fusion lines corresponding to different heights of the seam. Also, Charpy impact specimens were taken from different parts of the weld joint corresponding to the different heights. The influence of the heat input was investigated for 1.8 kJ mm-1 and 3.2 kJ mm-1. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required values could be reached in dependance on applied heat input.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - Hybrid laser-arc welding
KW - Thick-walled structures
KW - Charpy impact toughness
KW - Thermal cycles
PY - 2021
AN - OPUS4-53576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bakir, Nasim
T1 - In situ determination of the critical staining condition for solidification cracking during laser beam welding
N2 - Using a novel optical measurement technique together with the OF algorithm, a two-dimensional deformation analysis during welding was conducted.
The OF technique was the first of its kind to provide a measurement of the full strain field locally in the immediate vicinity of the solidification front. The local critical strain and strain rate in vicinity of the solidification front has observed 1.57%, 28 %/s, respectively.
T2 - Lane 2020
CY - Online meeting
DA - 07.09.2020
KW - Optical measurement technique
KW - Laser beam welding
KW - Solidification cracking
PY - 2020
AN - OPUS4-51741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Openness, Curiosity and Identity
N2 - I am introducing early-career researchers to my view on the academic career. I highlighted openness with regard to people. I mentioned my interest in multiple fields of the natural sciences, driving my curiosity. I additionally highlight my core belief that science is a team sport.
T2 - Open Minds – Exploring Science Careers
CY - Berlin, Germany
DA - 05.03.2026
KW - Materials Informatics
PY - 2026
AN - OPUS4-65632
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Röder, Bettina
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point. Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools.
KW - Mechanochemistry
KW - Polymorphism
KW - TRIS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564728
DO - https://doi.org/10.1039/d2fd00115b
SP - 1
EP - 16
PB - Royal Society of Chemistry
AN - OPUS4-56472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Scheuschner, Nils
A1 - Altenburg, Simon
A1 - Pignatelli, Giuseppe
A1 - Gornushkin, Igor B.
A1 - Baensch, Franziska
A1 - Rethmeier, Michael
T1 - In-situ Prozessüberwachung beim Laser-Pulver-Auftragschweißen (LPA) mittels Thermografie, optischer Emissionsspektroskopie (OES) und Schallemissionsanalyse (SEA)
N2 - Vor allem in den letzten Jahren ist das Interesse der Industrie an der additiven Fertigung deutlich gestiegen. Die Vorteile dieser Verfahren sind zahlreich und ermöglichen eine ressourcenschonende, kundenorientierte Fertigung von Bauteilen, welche zur stetigen Entwicklung neue Anwendungsbereiche und Werkstoffe führen. Aufgrund der steigenden Anwendungsfälle, nimmt auch der Wunsch nach Betriebssicherheit unabhängig von anschließenden kostenintensiven zerstörenden und zerstörungsfreien Prüfverfahren zu. Zu diesem Zweck werden im Rahmen des von der BAM durchgeführten Themenfeldprojektes „Prozessmonitoring in Additive Manufacturing“ verschiedenste Verfahren auf ihre Tauglichkeit für den in-situ Einsatz bei der Prozessüberwachung in der additiven Fertigung untersucht. Hier werden drei dieser in-situ Verfahren, die Thermografie, die optische Emissionsspektroskopie und die Schallmissionsanalyse für den Einsatz beim Laser-Pulver-Auftragschweißen betrachtet.
T2 - 41. Assistentenseminar der Füge- und Schweißtechnik
CY - Magdeburg, Germany
DA - 02.09.2020
KW - Laser-Pulver-Auftragschweißen (LPA)
KW - Thermographie
KW - Optische Emissionsspektroskopie (OES)
KW - Schallemissionsanalyse (SEA)
PY - 2021
SN - 978-3-96144-141-9
VL - 370
SP - 132
EP - 140
PB - DVS MEdia
CY - Düsseldorf
AN - OPUS4-53967
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Numerische Simulation im 3D-Druck
N2 - Die numerische Simulation hilft, Probleme bei additiven Bauprozessen früh zu erkennen und Optimierungspotentiale auszuschöpfen. Ziel ist, im additiven Auftragschweißen (DED) die Zahl der nötigen Versuche durch Vorhersagen zu verringern und Prozessgrößen zu visualisieren. Eine besondere Anwendung der Simulation ist die Generierung verzugskompensierter Geometrien: Durch die Berechnung des Bauteilverzugs kann die Geometrie vor dem Bauen so verändert werden, dass sie mit Verzug die gewünschte Toleranz erreicht. So kann Zerspanvolumen und Aufmaß reduziert werden.
KW - Schweißsimulation
KW - FEM
KW - Auftragschweißen
KW - Additive Fertigung
KW - Verzug
PY - 2020
IS - 4
SP - 45
EP - 48
AN - OPUS4-51097
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
T1 - Raw data for "Automated bonding analysis with crystal orbital Hamilton populations"
N2 - Raw data corresponding to the following paper: 10.1002/cplu.202200123.
KW - Automation
KW - High-throughput computations
KW - Bonding analysis
PY - 2022
UR - https://doi.org/10.5281/zenodo.6373369
DO - https://doi.org/10.5281/zenodo.6373368
PB - Zenodo
CY - Geneva
AN - OPUS4-55175
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simón Muzás, Juan
A1 - Brunner-Schwer, C.
A1 - Rethmeier, Michael
A1 - Hilgenberg, Kai
T1 - Mitigation of liquation cracking in laser welding of pairs of L-PBF processed and wrought plates of Inconel 718
N2 - Laser welding is an appropriate technique for joining Laser Powder Bed Fusion (L-PBF) parts together and to conventional wrought ones. The potential consists of profiting from synergies between additive and conventional manufacturing methods and overcoming the existing limitations of both. On the one hand, L-PBF is a widely spread metal-based additive manufacturing technique suitable for generating complex parts which can present intrinsic designed cavities, conformal cooling channels, and filigree structures contributing to sustainable manufacturing and efficiency-oriented designs. On the other hand, chamber sizes for producing L-PBF parts are limited, and the process is time-consuming. Thus, its employment is not for every geometry justified. Additionally, they are in most cases individual elements of a larger assembly and need to be joined together to conventionally fabricated parts.
The present research suggests laser welding parameters to adequately bond pairs of wrought and L-PBF processed plates and two L-PBF plates of Inconel 718 in butt position. L-PBF samples are printed in three different build-up orientations. Additionally, the influence of as-built L-PBF roughness qualities and usual pre-weld preparations such as edge milling are examined. The effect of normed pre-weld heat treatments is also contemplated. Identified cracks are analyzed by means of EDS in order to confirm the present phases on the areas of interest. EBSD is also employed to obtain a clear depiction of the crystallographic texture and distribution of the hot cracks.
The quality of the weldment was examined according to existing standards. Substantial differences in seam geometry and microstructure across different edge’s surface qualities and build directions of stress relieved L-PBF parts have not been detected. Nevertheless, even if no other irregularities are present in the seam, variability in liquation cracking susceptibility has been confirmed. This defect is prone to happen when parts made of this nickel-based superalloy are welded together when not enough precautions are taken. It has been determined that grain size and ductility of the material before welding play a crucial role and mitigating or intensifying these imperfections. Moreover, recommendations are presented to avoid this potential welding defect.
T2 - IIW 2022 International Conference on Welding and Joining
CY - Tokyo, Japan
DA - 17.07.2022
KW - Hybrid Part
KW - Liquation Cracking
KW - Build-up Orientation
KW - Pre-weld Preparation
KW - Heat treatment
KW - Inconel 718
KW - Laser Welding
KW - Laser Powder Bed Fusion
KW - Selective Laser Melting
KW - SLM
KW - L-PBF
KW - PBF-LB/M
KW - LW
PY - 2022
UR - www.iiw2022.com
SP - 372
EP - 375
PB - The International Institute of Welding (IIW)
CY - Tokyo, Japan
AN - OPUS4-56066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altmann, Korinna
T1 - Microplastic occurrence in urban sewage systems: Identification of sources for pathways into the environment
N2 - All over the world, microplastic (MP) particles (particle size: 1 - 1.000 µm) are found in water, soil, air, biota and even food products. But plenty of these discussed findings are based on a very low number of real datasets, which are extrapolated to general projections. Furthermore, most data are not comparable because the strategies for sampling, sample preparation and detection methods are not harmonised/ or standardised. This would require extensive proficiancy tests. Because of the ubiquity presence and the unclear risks, which might arise from those particles, various political and environmental organisations (i.e. OECD, UNEP, WHO) identify the reduction of plastic entry in the environment as a key challenge for now and the future. This challenge includes the identification of relevant entry pathways but also the demand of harmonised, meaningful and reliable analytical procedures.
Regarding this task within the last few years, a fast practical solution for MP analysis has been developed, which includes the steps of representative sampling, adequate sample preparation and fast detection. Sampling is done by fractional filtration over sieves with mesh sizes of 500, 100, 50 and 5 µm [1]. The received samples are measured by ThermoExtraction/Desorption-Gas Chromatography-Mass Spectrometry (TED-GC-MS) [1,2]. for the most abundant polymers used in practice, which are polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polyamide (PA) and acrylate as well as styrene-butadiene-rubber (SBR), a main component of tires.
The present presentation will give first-time insight in a comprehensive dataset of microplastic analysis for an exemplary urban sewage system. MP mass contents of different waters at several days, such as greywater, stormwater retention tank, influent and effluent of a wastewater treatment plant (WWTP) within an urban sewage system in Germany are determined. Furthermore, the mass of the polymers found in dry weather and rain weather flow are compared. The use of these large datasets allows first expressive conclusions regarding the contribution of urban sewage system to the MP entry sources in the environments.
We found PP and PS in all different waters. Furthermore, there is SBR in influent and also in effluent of the WWTP. Surprisingly, we could also detect hugh amounts of PE in the effluent of the WWTP.
T2 - SETAC Europe 2020
CY - Online meeting
DA - 03.05.2020
KW - Microplastic analysis
KW - TED-GC/MS
KW - Microplastic particles
KW - Microplastic mass contents
PY - 2020
AN - OPUS4-50795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Elucidation of the Laser Beam Energy Attenuation by the Vapor Plume Formation during High Power Laser Beam Welding
N2 - In high-power laser beam welding, a common phenomenon is the formation of a keyhole caused by the rapid evaporation of the material. Under atmospheric pressure, this evaporation generates a vapor plume that interacts with the laser beam, leading to energy attenuation and scattering of the laser radiation along its path. These interactions affect the stability of the process and the overall weld quality. This study investigates the influence of the vapor plume on the weld pool and keyhole dynamics during high-power laser beam welding of AlMg3 aluminum alloy through experimental and numerical approaches. The primary goal is to identify key vapor plume characteristics, particularly its length fluctuations, and to improve the accuracy of the numerical models. To achieve this, an algorithm was developed for the automated measurement of the vapor plume length using high-speed imaging and advanced data processing techniques. The measured plume length is then used to estimate the additional vapor heating and laser energy attenuation using the Beer–Lambert law. A refined numerical CFD model, incorporating 3D transient heat transfer, fluid flow, and ray tracing, was developed to evaluate the vapor plume’s impact. Results show that already the time-averaged plume length effectively captures its transient influence and aligns well with experimental weld seam geometries. Additionally, energy scattering and absorption caused by the vapor plume led to a wider weld pool at the top surface. The study also shows an increased percentage of keyhole collapses due to the reduced laser power absorption at the keyhole bottom, further highlighting the importance of accurately modeling vapor plume effects.
T2 - International Congress of Applications of Lasers & Electro-Optics 2025
CY - Orlando, FL, USA
DA - 12.10.2025
KW - Laser beam welding
KW - Vapor plume formation
KW - Weld pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2025
AN - OPUS4-64816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Dufrenoy, Philippe
A1 - Magnier, Vincent
T1 - Rationalizing the microstructure interplay in the thermal conductivity of a metal matrix composite via 3D imaged-based finite element modeling
N2 - The thermal performance of metallic brake lining materials plays a decisive role in the safety and efficiency of high-speed railway braking systems. In this study, a combined experimental–numerical methodology is developed to rationalize the influence of microstructural constituents on the effective thermal conductivity of a sintered metal matrix composite (MMC) brake lining. Laser Flash Analysis (LFA) is first employed to determine the thermal conductivity of some individual constituents as well as that of reference composites. X-ray CT (XCT) provides three-dimensional reconstructions of the microstructure that are subsequently used to generate realistic image-based finite element meshes. The unknown thermal conductivities of the graphite particles are identified through a Finite Element Model Updating (FEMU) scheme, where numerical predictions of the effective conductivity are iteratively matched to LFA measurements. These findings highlight the strong anisotropy of graphite particles and their favored orientation after compaction, which governs heat transport pathways. Moreover, the presence of intra-, inter-, and inter-connectivity porosity within and around the graphite is shown to significantly reduce the transverse conductivity, rationalizing the discrepancy between the FEM predictions and experimental values. Overall, the proposed approach demonstrates how combining LFA, XCT and FEMU enables the identification of constituent-level conductivities and provides new insights into the microstructure/thermal-property relationships of MMC brake linings.
KW - Brake lining material
KW - Thermal conductivity
KW - Graphite particles
KW - Laser flash analysis (LFA)
KW - X-ray computed tomography (XCT)
KW - 3D finite element model updating (FEMU)
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657756
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2026.128735
SN - 0017-9310
VL - 264
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Getenet, M.
A1 - Garcia-Ruiz, J. M.
A1 - Otálora, F.
A1 - Emmerling, Franziska
A1 - Al-Sabbagh, Dominik
A1 - Verdugo-Escamilla, E.
T1 - A comprehensive methodology for monitoring evaporitic mineral precipitation and hydrochemical evolution of saline lakes: The case of Lake Magadi soda brine (East African Rift Valley, Kenya)
N2 - Lake Magadi, East African Rift Valley, is a hyperalkaline and saline soda lake highly enriched in Na+, K+, CO32–, Cl–, HCO3–, and SiO2 and depleted in Ca2+ and Mg2+, where thick evaporite deposits and siliceous sediments have been forming for 100 000 years. The hydrogeochemistry and the evaporite deposits of soda lakes are subjects of growing interest in paleoclimatology, astrobiology, and planetary sciences. In Lake Magadi, different hydrates of sodium carbonate/bicarbonate and other saline minerals precipitate. The precipitation sequence of these minerals is a key for understanding the hydrochemical evolution, the paleoenvironmental conditions of ancient evaporite deposits, and industrial crystallization. However, accurate determination of the precipitation sequence of these minerals was challenging due to the dependency of the different hydrates on temperature, water activity, pH and pCO2, which could induce phase transformation and secondary mineral precipitation during sample handling. Here, we report a comprehensive methodology applied for monitoring the evaporitic mineral precipitation and hydrochemical evolution of Lake Magadi. Evaporation and mineral precipitations were monitored by using in situ video microscopy and synchrotron X-ray diffraction of acoustically levitated droplets. The mineral patterns were characterized by ex situ Raman spectroscopy, X-ray diffraction, and scanning electron microscopy. Experiments were coupled with thermodynamic models to understand the evaporation and precipitation-driven hydrochemical evolution of brines. Our results closely reproduced the mineral assemblages, patterns, and textural relations observed in the natural setting. Alkaline earth carbonates and fluorite were predicted to precipitate first followed by siliceous sediments. Among the salts, dendritic and acicular trona precipitate first via fractional crystallization─reminiscent of grasslike trona layers of Lake Magadi. Halite/villiaumite, thermonatrite, and sylvite precipitate sequentially after trona from residual brines depleted in HCO3–. The precipitation of these minerals between trona crystals resembles the precipitation process observed in the interstitial brines of the trona layers. Thermonatrite precipitation began after trona equilibrated with the residual brines due to the absence of excess CO2 input. We have shown that evaporation and mineral precipitation are the major drivers for the formation of hyperalkaline, saline, and SiO2-rich brines. The discrepancy between predicted and actual sulfate and phosphate ion concentrations implies the biological cycling of these ions. The combination of different in situ and ex situ methods and modeling is key to understanding the mineral phases, precipitation sequences, and textural relations of modern and ancient evaporite deposits. The synergy of these methods could be applicable in industrial crystallization and natural brines to reconstruct the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and extraterrestrial planets.
KW - Crystallization
KW - Precipitation
KW - Crystals
KW - Evaporation
KW - Minerals
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546712
DO - https://doi.org/10.1021/acs.cgd.1c01391
SN - 1528-7483
VL - 22
IS - 4
SP - 2307
EP - 2317
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-54671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ueltzen, Katharina
T1 - Unveiling the potential of the Kanamori-Goodenough-Anderson rules for magnetic property prediction
N2 - Recently, machine learning of magnetic properties of transition metal compounds has attracted large interest due to environmental and availability issues of rare-earth-based functional magnetic materials. Surprisingly, bond-angle-derived features were not found to be relevant for magnetic structure prediction in previous studies using DFT-computed labels. This contrasts with a well-known magnetism heuristic, the Kanamori-Goodenough-Anderson (KGA) rules of superexchange. We review magnetic interaction trends within the MAGNDATA database of experimentally determined magnetic structures. Observed trends follow the KGA rules „of thumb“ and exceptions can be rationalized. We introduce a new, informative label for predicting magnetic structures that can be extended to magnetic sites and structures of arbitrary complexity. Bond-angle-derived features are found to be highly relevant for magnetic structure prediction.
T2 - Faraday Discussion: Data-driven discovery in the chemical sciences
CY - Oxford, UK
DA - 10.09.2024
KW - Magnetism
KW - High-throughput analysis
KW - Machine learning
KW - Transition metal compounds
PY - 2024
AN - OPUS4-62250
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ueltzen, Katharina
T1 - Revisiting the Kanamori-Goodenough-Anderson rules for magnetic property prediction
N2 - Recently, machine learning of magnetic properties of transition metal compounds has attracted large interest due to environmental and availability issues of rare-earth-based functional magnetic materials. Surprisingly, bond-angle-derived features were not found to be relevant for magnetic structure prediction in previous studies using DFT-computed labels. This contrasts with a well-known magnetism heuristic, the Kanamori-Goodenough-Anderson (KGA) rules of superexchange. We review magnetic interaction trends within the MAGNDATA database of experimentally determined magnetic structures. Observed trends follow the KGA rules „of thumb“ and exceptions can be rationalized. We introduce a new, informative label for predicting magnetic structures that can be extended to magnetic sites and structures of arbitrary complexity. Bond-angle-derived features are found to be highly relevant for magnetic structure prediction.
T2 - 60th Symposium on Theoretical Chemistry (STC 2024)
CY - Braunschweig, Germany
DA - 02.09.2024
KW - Magnetism
KW - High-throughput analysis
KW - Machine learning
KW - Transition metal compounds
PY - 2024
AN - OPUS4-62249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Benner, Philipp
A1 - Grandel, Jonas
T1 - A shortcut towards phonon predictions
N2 - Phonon calculations with ab-initio methods are computationally expensive. The use of universal machine learning models reduces the cost, but raises concerns about prediction quality. Fine-tuning with only a few structures, improves predictions of phonons, thermal properties and especially diffusive thermal conductivity, while reducing computational cost by a factor of 10 in average compared to DFT methods.
T2 - DPG Frühjahrstagung
CY - Regensburg, Germany
DA - 16.03.2025
KW - Machine Learning
KW - MACE
KW - Phonons
PY - 2025
AN - OPUS4-62770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 2)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852107
PB - Zenodo
CY - Geneva
AN - OPUS4-57442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
A1 - Bustamante, Joana
A1 - Mieller, Björn
A1 - Stawski, Tomasz
A1 - George, Janine
A1 - Knoop, F.
T1 - High-quality zirconium vanadate samples for negative thermal expansion (NTE) analysis
N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which exhibits significant isotropic contraction over a broad temperature range (~150°C < T < 800°C). The linear thermal expansion coefficient of ZrV2O7 is −7.1×10-6 K-. Therefore, it can be used to create composites with controllable expansion coefficients and prevent destruction by thermal shock.
Material characterization, leading to application, requires pure, homogenous samples of high crystallinity via a reliable synthesis route. While there is a selection of described syntheses in the literature, it still needs to be addressed which synthesis route leads to truly pure and homogenous samples. Here, we study the influence of the synthesis methods (solid-state, sol-gel, solvothermal) and their parameters on the sample's purity, crystallinity, and homogeneity. The reproducibility of results and data obtained with scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric analysis (DSC/TGA) were analyzed extensively. The sol-gel method proves superior to the solid-state method and produces higher-quality samples over varying parameters. Sample purity also plays an important role in NTE micro and macro-scale characterizations that explain the impact of porosity versus structural changes.
Moreover, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation, temperature-dependent effective harmonic potentials) in combination with experimental methods to follow and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder, microstructure, and defects. Khosrovani et al. and Korthuis et al., in a series of diffraction experiments, attributed the thermal contraction of ZrV2O7 to the transverse thermal motion of oxygen atoms in V-O-V linkages. In addition to previous explanations, we hypothesize that local disorder develops in ZrV2O7 crystals during heating.
We are working on the experimental ZrV2O7 development and discuss difficulties one might face in the process as well as high-quality sample significance in further investigation. The obtained samples are currently used in the ongoing research of structure analysis and the negative thermal expansion mechanism.
T2 - 4th International Symposium on Negative Thermal Expansion and Related Materials (ISNTE-4)
CY - Padua, Italy
DA - 04.07.2023
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - TDEP
PY - 2023
AN - OPUS4-58132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ö.
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Hybrid laser arc welding of thick high-strength piepline steels of grade X120 with adapted heat input
N2 - The influence of heat input and welding speed on the microstructure and mechanical properties of single-pass hybrid laser arc welded 20mm thick plates of high-strength pipeline steel X120 were presented. The heat Input was varied in the range of 1.4 kJ mm−1 to 2.9 kJ mm−1, while the welding speed was changed between 0.5m min−1 and 1.5m min−1. A novel technique of bath support based on external oscillating electromagnetic field was used to compensate the hydrostatic pressure at low welding velocities. A major advantage of this technology is, that the welding speed and thus the cooling time t8/5 can be variated in a wide parameter window without issues regarding the weld root quality. The recommended welding thermal cycles for the pipeline steel X120 can be met by that way. All tested Charpy-V specimens meet the requirements of API 5 L regarding the impact energy. For higher heat inputs the average impact energy was 144 ± 37 J at a testing temperature of −40 °C. High heat Input above 1.6 kJ mm−1 leads to softening in the weld metal and heat-affected-zone resulting in loss of strength. The minimum tensile strength of 915 MPa could be achieved at heat inputs between 1.4 kJ mm−1 and 1.6 kJ mm−1.
KW - High-strength low-alloy steel
KW - Hybrid laser-arc welding
KW - Mechanical-technological properties
KW - Microstructure
KW - Toughness
KW - Pipeline steel of grade X120
PY - 2020
DO - https://doi.org/10.1016/j.jmatprotec.2019.116358
SN - 0924-0136
VL - 275
SP - 116358
PB - Elsevier B.V.
AN - OPUS4-50008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Materials design using chemical heuristics, workflows, and machine learning
N2 - Bonds and local atomic environments are key descriptors of material properties, used to establish design rules and heuristics, and serve as descriptors in machine-learned interatomic potentials and the general machine learning of material properties.
Software implementations such as ChemEnv and LobsterEnv identify local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis (here using Crystal Orbital Hamilton Populations as computed with LOBSTER). Fully automated workflows and analysis tools now enable large-scale quantum-chemical bonding analysis. The first part of the lecture will demonstrate how these tools help develop new machine-learning models and intuitive understandings of material properties.
New universal machine-learned interatomic potentials, such as MACE-MP-0, have been developed. The second part of the lecture will showcase how these potentials, combined with DFT, can accelerate research. It will focus on the interplay between DFT and machine-learned interatomic potentials, presenting automated workflows for training, fine-tuning, and benchmarking these potentials, implemented in our software autoplex. Additionally, it will show how to train new interatomic potentials from scratch by exploring potential energy surfaces, with the potential to enhance current universal machine-learned potentials.
The lecture will also discuss the trend toward automation in computational materials science and our recent contributions.
T2 - FAIRmat Seminar
CY - Berlin, Germany
DA - 05.06.2025
KW - Automation
KW - Machine learning
KW - Synthesizability
KW - Sustainable materials design
KW - High-throughput
KW - Bonding analysis
KW - Materials acceleration platforms
PY - 2025
AN - OPUS4-63315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash
T1 - Harnessing quantum chemical bonding analysis descriptors for material property predictions
N2 - Examining the bonding between their constituent atoms in crystalline materials has played a vital role in understanding material properties.[1–4] For instance, low thermal conductivity in materials is typically attributed to its anharmonicity, which has been reported to arise from strong antibonding interactions and local environment distortions.[5–7] The bonds in the material are often quantified in terms of bond strength and can be extracted from crystalline materials using density-based[8], energy-based[9], and orbital-based[10] methods. LOBSTER[11] is a program that relies on an orbital-based method to extract such bonding information by projecting the plane wave-based wave functions of modern density functional theory computations (DFT) onto a local atomic orbital basis. Since our goal was to use bonding analysis descriptors for material property predictions, we needed to first systematically generate large quantities of bonding analysis data. To streamline this process, we have developed a user-friendly workflow[12], which is now also part of the atomate2[13] package that can generate bonding information data extracted using the LOBSTER program for crystalline materials. This workflow requires only the structure as input from the user. Employing this workflow, we have generated for ~13000 crystalline compounds such bonding analysis data. To create new descriptors from these data, we use our package LobsterPy.[14] The curated descriptors span different types, including statistical representations of bonding characteristics for traditional ML algorithms (e.g., random forests), textual descriptions for large language models (LLMs), and structure graphs for graph neural networks (GNNs). These descriptors are then tested by employing them in several state-of-the-art ML algorithms and architectures to predict the mechanical, vibrational, and thermal properties of crystalline materials. Through this work, we are not only able to demonstrate how one can enhance the model’s predictive accuracy[15] by incorporating quantum chemical bonding-based descriptors alongside typical composition and structure-based descriptors but it also aids in uncovering relationships between bonding and materials properties on a larger scale, which was not possible before.
T2 - MRS SPRING 2025
CY - Seattle, WA, USA
DA - 07.04.2025
KW - Bonding analysis
KW - Machine learning
KW - Materials Descriptors
PY - 2025
AN - OPUS4-63001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Janssen, Jan
A1 - George, Janine
A1 - Geiger, Julian
A1 - Bercx, Marnik
A1 - Wang, Xing
A1 - Ertural, Christina
A1 - Schaarschmidt, Joerg
A1 - Ganose, Alex M.
A1 - Pizzi, Giovanni
A1 - Hickel, Tilmann
A1 - Neugebauer, Joerg
T1 - A Python workflow definition for computational materials design
N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements
the PWD in AiiDA, jobflow, and pyiron.
KW - Automation
KW - Workflows
KW - Materials Design
KW - Multi-scale simulation
KW - Digitalization
PY - 2025
DO - https://doi.org/10.5281/zenodo.15516179
PB - Zenodo
CY - Geneva
AN - OPUS4-63233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, Julius
A1 - Schmidt, Jonathan
A1 - Jokisch, Torsten
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Prozessführung und erreichbare Nahtqualitäten: Elektronenstrahlschweißen von additiv gefertigtem Inconel 939
N2 - Additive Fertigungstechnologien wie das Laser-Pulverbett-Verfahren bieten großes Potenzial für die Fertigung von Neu und Ersatzteilen für stationäre Gasturbinen aus Nickelsuperlegierungen wie Inconel 939 (IN939). Um die Integration in bestehende Baugruppen zu ermöglichen und Bauraumbeschränkungen zu überwinden, muss die Prozesskette der additiven Fertigung um geeignete Fügetechniken erweitert werden. Die vorliegende Arbeit beschäftigt sich daher mit dem Schweißen von Inconel 939. Hierbei werden Bleche aus Gussmaterial und der additiven Herstellung mittels Laser im Pulverbett beim Elektronenstrahlschweißen verglichen. Im Fokus der Untersuchung stehen die erreichbare Nahtqualität im Hinblick auf geometrische Unregelmäßigkeiten sowie innere Defekte in Form von Mikrorissen in der Wärmeeinflusszone. Bei der Auswertung der geschweißten Proben zeigen sich keine Unterschiede in der Ausbildung der Nahtform zwischen dem additiv gefertigten Material und dem Gusswerkstoff. Für beide Materialien ließ sich bei hohen Vorschubgeschwindigkeiten von 20 mm/s die höchste Bewertungsgruppe für Strahlgeschweißte Nähte nach DIN EN ISO 13919-1 erreichen. Unabhängig von der Herstellungsart zeigen beide Materialien eine Zunahme der Rissneigung mit steigendem Vorschub. Das Material aus der additiven Herstellung weist aufgrund seiner Mikrostruktur insgesamt jedoch deutlich weniger Mikrorisse auf, was Potenzial für die Anwendung in der Praxis eröffnet.
KW - Elektronenstrahlschweißen
KW - PBF-LB/M
KW - Inconell939
PY - 2025
UR - https://www.schweissenundschneiden.de/artikel/prozessfuehrung-und-erreichbare-naht-qualitaeten-elektronenstrahlschweissen-von-additiv-gefertigtem-inconel-939
DO - https://doi.org/10.53192/SUS202510
VL - 77
IS - 10
SP - 2
EP - 8
PB - DVS Media Verlag
CY - Eltville am Rhein, Deutschland
AN - OPUS4-64300
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolmangadi, Mohamed Aejaz
T1 - Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation
N2 - For the first time, dielectric and calorimetric investigations of a homologous series of Janus polynorbornenes with rigid main backbones and flexible −Si(OR)3 side groups of differing length alkyl chains (R = propyl, butyl, hexyl, octyl, and decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α-relaxation. The former can be assigned to localized fluctuations, while the latter is related to the glassy dynamics of the flexible −Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain-rich and backbone-rich domains. This is confirmed through temperature-modulated differential scanning calorimetry (TMDSC) measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using fast scanning calorimetry employing both fast heating and cooling rates. This is complemented with scattering experiments that show how the size of the alkyl chain-rich domains increases with the side chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with −Si(OR)3 side groups, which is interpreted in terms of a percolation model.
T2 - DPG Online Spring Conference 2021
CY - Online meeting
DA - 22.03.2021
KW - Dynamics
KW - Glass transition
KW - Conductivity
PY - 2021
AN - OPUS4-52335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
T1 - Handling of orbital-resolved "ICOHPLIST.lobster" files from the software Lobster in pymatgen
N2 - Python Materials Genomics (pymatgen) is a robust materials analysis code that defines classes for structures and molecules with support for many electronic structure codes. This open-source software package powers the Materials Project.
In this particular contribution, the handling of obital-resolved "ICOHPLIST.lobster" files from Lobster was implemented in the software package (github handle: @JaGeo).
KW - Bonding analysis
KW - Density functional theory
PY - 2023
UR - https://github.com/materialsproject/pymatgen/pull/2993
PB - Zenodo
CY - Geneva
AN - OPUS4-57569
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Quality improvement of laser welds on thick duplex plates by laser cladded buttering
N2 - Because of its excellent corrosion resistance, high tensile strength and high ductility, duplex stainless steel 2205 offers many areas of application. Though laser beam welding accompanied by high cooling rates, duplex steels tend to perform higher ferrite contents in weld metal as the base metal, which leads to a reduction of ductility and corrosion resistance of the weld joint. To overcome this problem, a solution, based on buttering the plate edges by laser metal deposition (LMD) with material containing higher Ni concentrations prior to laser welding was suggested.
In this context different process parameters for LMD process were investigated. In a second step the possibility of welding those edges defect free while achieving balanced austenite-ferrite ratio was verified with metallographic analysis, Electron Backscatter Diffraction (EBSD) and impact testing according to Charpy.
T2 - Lasers in Manufacturing (LiM) 2019
CY - Munich, Germany
DA - 24.06.2019
KW - Laser Metal Deposition; Laser Beam Welding; Duplex; Stainless Steel
PY - 2020
SP - We_A31_4_4-1
EP - We_A31_4_4-6
PB - WLT (Wissenschaftliche Gesellschaft für Lasertechnik)
AN - OPUS4-50143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meyerdierks, M.
A1 - Schreiber, V.
A1 - Böhne, Ch.
A1 - Jüttner, S.
A1 - Meschut, G.
A1 - Rethmeier, Michael
T1 - Validierung von Methoden zur Vermeidung von Liquid Metal Embrittlement an realitätsnahen Prinzipbauteilen (IGF 21483 BG / P 1488)
N2 - Ziel des Forschungsprojekts ist es, eine Korrelation zwischen Gleeble-Heißzug-Prüfverfahren und Widerstandspunktschweiß-basierten Prüfverfahren herzustellen. Es soll die Effektivität von Methoden zu Vermeidung von Liquid Metal Embrittlement an realitätsnahen Prinzipbauteilen bewertet werden. Weiterhin soll Kenntnis über Auswirkungen von LME Rissen auf das Tragverhalten von realitätsnahen Prinzipbauteilen gewonnen werden.
T2 - 30. Schweißtechnische Fachtagung
CY - Barleben, Germany
DA - 07.10.2021
KW - Liquid Metal Embrittlement
KW - Gleeble
KW - Heißzug
KW - Widerstandpunktschweißen
KW - Flüssigmetallversprödung
PY - 2021
AN - OPUS4-54061
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Towards Structured Data Spaces: Prototypical Application of Semantic Technologies as a Driver for Innovation in Materials Science
N2 - In the pursuit of advancing development and digitalization within materials science, ensuring quality assurance, interoperability, and adherence to FAIR principles is significant. To address these aspects, semantic technologies are employed for storage, processing, and contextualization of data, offering machine-actionable and human-readable knowledge representations crucial for data management.
This presentation showcases the prototypical application of generic approaches of knowledge representation in materials science. It includes the design and documentation of graph patterns that may be compiled into rule-based semantic shapes. The development and application of the PMD Core Ontology 3.0 (PMDco 3.0) tailored for materials science is highlighted. Its integration into daily lab life is demonstrated through its functional incorporation into electronic lab notebooks (ELN). Examples of material processing and standardized mechanical testing illustrate how knowledge graph operations enhance ELN capabilities, providing a generalizable unified approach for managing diverse experimental data from different sources with automation potentials.
T2 - TMS Specialty Congress 2025
CY - Anaheim, CA, USA
DA - 15.06.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
KW - Plattform MaterialDigital
PY - 2025
AN - OPUS4-63401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
A1 - Hammerschmidt, T.
A1 - Stotzka, R.
T1 - Demonstration of the Infrastructure Use Case 02: Framework for curation and distribution of reference datasets
N2 - In our current view, reference datasets in the MSE domain represent specific material properties, e.g., structural, mechanical, … characteristics. A reference dataset must fulfill high-quality standards, not only in precision of measurement but also in a comprehensive documentation of material, processing, and testing history (metadata). This Infrastructure Use Case (IUC) aims to develop a framework for generating reference material datasets using creep data of a single crystal Ni-based superalloy as a best practice example. In a community-driven process, we aim to encourage the discussion and establish a framework for the creation and distribution of reference material datasets. In this poster presentation, we highlight our current vision and activities and intend to stimulate the discussion about the topic reference datasets and future collaborations and work.
T2 - NFDI-MatWerk Conference
CY - Siegburg, Germany
DA - 27.06.2023
KW - Referenzdaten
KW - Reference data
KW - Creep
KW - Metadata schema
KW - Syngle Crystal alloy
PY - 2023
AN - OPUS4-57924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Advancing Industrial Mechanochemistry: Real-Time Insights for Sustainable, Solvent-Free Manufacturing
N2 - Reactive extrusion has emerged as a continuous approach for conducting mechanochemical reactions on a large scale. However, the use of this method under industrial conditions is hindered by limited understanding. In this study, we unveil the black box of reactive extrusion by employing energy-dispersive X-ray diffraction (EDXRD) to collect time- and spatially resolved in situ data. Our findings demonstrate the EDXRD method’s applicability to a range of chemical transformations and conditions associated with reactive extrusion.
T2 - Chemie-Kolloquium & IfC Science Day
CY - Berlin, Germany
DA - 22.01.2025
KW - Mechanochemistry
PY - 2025
AN - OPUS4-63801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
A1 - Zerbst, Uwe
A1 - Madia, Mauro
T1 - Der Schwellenwert der da/dN-∆K-Kurve als Auslegungskriterium für die Bauteilbewertung
N2 - Für die Bestimmung der Restlebensdauer zyklisch beanspruchter Bauteile kommt dem Schwellenwert für Ermüdungsrissausbreitung ∆Kth und dem sich anschließenden Schwellenwertbereich der da/dN-∆K-Kurve große Bedeutung zu. Dem stehen Unsicherheiten bei der Bestimmung und Analyse gegenüber. Der Aufsatz befasst sich mit der Ermittlung des sogenannten intrinsischen Schwellenwerts, der als robuster Eingangsparameter für eine „rissschließfreie“ Analyse der Restlebensdauer von entscheidender Bedeutung ist.
T2 - Tagung Werkstoffprüfung 2020
CY - Online meeting
DA - 03.12.2020
KW - Schadenstolerante Bauteilauslegung,
KW - Intrinsischer Schwellenwert gegen Ermüdungsrissausbreitung
KW - Restlebensdauer
PY - 2020
DO - https://doi.org/10.48447/WP-2020-025
SP - 1
EP - 8
AN - OPUS4-52788
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos, José Antonio
A1 - Bienert, M.
A1 - Gugin, Nikita
A1 - Emmerling, Franziska
A1 - Maiwald, Michael
T1 - A database to select affordable MOFs for volumetric hydrogen cryoadsorption considering the cost of their linkers
N2 - Physical adsorption at cryogenic temperature (cryoadsorption) is a reversible mechanism that can reduce the pressure of conventional compressed gas storage systems. Metal–organic framework (MOF) materials are remarkable candidates due to the combination of high specific surface area and density which, in some cases, provide a high volumetric storage capacity. However, such extensive use of MOFs for this application requires the selection of affordable structures, easy to produce and made from feasible metallic and organic components. Herein, we introduce a MOF database detailing the crystallographic and porous properties of 3600 existing MOFs made from industrially relevant metals and their organic composition. The comparison of the available minimum costs of linkers allowed the creation of a database to select affordable structures with high potential for volumetric hydrogen storage by cryoadsorption, considering their composition based on individual or mixed building blocks. A user inter� face, available online, facilitates the selection of MOFs based on the properties or names of structures and linkers.
KW - MOF´s
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583619
DO - https://doi.org/10.1039/d3ma00315a
VL - 4
IS - 18
SP - 4226
EP - 4237
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58361
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schork, B.
A1 - Zerbst, Uwe
A1 - Kiyak, Yusuf
A1 - Kaffenberger, M.
A1 - Madia, Mauro
A1 - Oechsner, M.
T1 - Effect of the parameters of weld toe geometry on the FAT class as obtained by means of fracture mechanics-based simulations
N2 - The fracture mechanics-based IBESS approach is applied to the determination of FAT classes of butt welds with crack Initiation along the weld toe. The aim is an investigation of the effect of the geometrical parameters toe radius, flank angle, reinforcement and secondary notches such as roughness or undercuts. The influence of these parameters is discussed both individually and in combination; however, excluding statistical distributions of them and the material data. The results, when compared with conventional FAT classes for butt welds, are encouraging with respect to a potential contribution of IBESS to the discussion of more advanced quality criteria for welds. To that purpose, demands for further research are proposed.
KW - Fracture mechanics
KW - Weld toe geometry
KW - Fatigue crack initiation
KW - FAT class approach
PY - 2020
DO - https://doi.org/10.1007/s40194-020-00874-7
IS - 64
SP - 925
EP - 936
PB - Springer
AN - OPUS4-53079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Bio, Waste, Non-vegan – Fun, Food for Thought, or Future
N2 - Overview of the state of the art and current trends with the main topics:
- renewable sources in flame retardant polymers (flame retarded bio-polymers and biocomposites; bio-flame retardants, renewable adjuvants from industrial waste)
- flame retardancy meets sustainability
- concepts between analogy and out-of-the-box.
T2 - 18th SKZ International Conference on Trends in Fire Safety and InnovativeRFlame retardants for Plastics
CY - Würzburg/Rottendorf, Germany
DA - 27.09.2022
KW - Bio-polymer
KW - Bio-composite
KW - Renewable source
KW - Renewable adjuvants
KW - Vitrimer
KW - Bio-flame retardant
PY - 2022
AN - OPUS4-55840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocaño, Patricia
A1 - Ávila Calderón, Luis
A1 - Agudo Jácome, Leonardo
A1 - Rehmer, Birgit
A1 - Mohr, Gunther
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Effect of 700–900 °C heat treatments and room and high temperature tensile deformation on the microstructure of laser powder bed fused 316L stainless steel
N2 - The effect of post-processing heat treatments on the hierarchical microstructure evolution and mechanical strength of the austenitic stainless steel 316L produced by laser powder bed fusion has been investigated. Heat treatments between 700 and 900 ◦C and 0.5 to 3 h, were applied to samples treated at 450 ◦C for 4 h. The results showed a stable microstructure at all studied temperatures and times in terms of grain size, morphology, aspect ratio, density of low-angle grain boundaries, and texture. However, temperature and time promoted the diffusion of segregated elements together with a reduction in dislocation density and disappearance of the cellular structure. This was associated with a reduction in hardness and tensile proof strength at both room and high temperature. In addition, microstructural characterization coupled with thermodynamic CALPHAD-based equilibrium calculations showed that the formation of carbides and intermetallic phases was already visible after annealing at 800 ◦C for 3 hours, although these intermetallics did not affect the tensile properties at this level. Analysis of the microstructure evolution after tensile deformation showed differences in the deformation mechanisms at room and high temperature, with twinning and martensitic transformation occurring at room temperature, the latter not widely reported for additively manufactured 316L. Finally, comparisons with similar materials produced under comparable conditions showed differences in the tensile properties, attributed to differences in chemical composition and the associated presence of stacking faults in the undeformed state.
KW - Additive manufacturing
KW - 316L stainless steel
KW - Heat treatments
KW - Tensile properties
KW - Microstructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632471
DO - https://doi.org/10.1016/j.msea.2025.148469
SN - 0921-5093
VL - 939
SP - 1
EP - 24
PB - Elsevier
CY - Amsterdam
AN - OPUS4-63247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jentzsch, Stefan
A1 - Stock, Daniel
A1 - Häcker, Ralf
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
A1 - Klingbeil, Dietmar
A1 - Kindrachuk, Vitaliy
T1 - Shear Band Formation with Split Hopkinson Bar Experiments
N2 - The essence of dynamic failure is closely linked to dramatic shear deformations which often lead to the formation of adiabatic shear bands (ASB). Under high loading velocities and the subsequent rapid temperature increase, the localization of shear strain is crucial in view of safety issues of systems in mechanical and aircraft engineering, especially with respect to fast rotating components and diverse crash scenarios. In this research, we perform high speed impact tests at the split Hopkinson pressure bar (SHPB) setup and use particular hat-shaped specimen geometries that resemble the stresses and failure conditions at the component level.
In the first step, we specify a notched specimen geometry using finite element (FE) simulations to ensure pure shear. Further, quasi-static compressive tests and a series of impact tests at high strain rates of 10^3-10^4 s^-1 are conducted on specimens manufactured from a fine-grain structural steel with the properties of S355. Optical microscopy and electron backscatter diffraction (EBSD) of the sheared zones unveil significant localization to maximal shear strains of about 0.9 accompanied by grain refinement by factors 5 to 14. The displacements across the surface of the specimens are captured with subset-based local digital image correlation (DIC) during the impact time, and serve as an objective to validate a viscoplastic constitutive relationship. More precisely, the deformation distribution is accurately reproduced by the widely recognized Johnson-Cook (JC) model, which features an enhanced description of damage evolution. Thus, combining experimental and characterization techniques, continuum mechanics and reasonable optimization strategies for the identification of model parameters provides an efficient approach for comprehensive insights into the strain localization behaviour and its impact on the mechanical performance of S355 under extreme strain rates and deformations.
KW - Adiabatic shear bands
KW - Finite element analysis
KW - Viscoplastic material modelling
KW - Split Hopkinson pressure bar
KW - Hat-shaped specimen
KW - Johnson–Cook parameter identification
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613339
DO - https://doi.org/10.1016/j.ijmecsci.2024.109749
VL - 284
SP - 1
EP - 14
PB - Elsevier BV
AN - OPUS4-61333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abel, Andreas
A1 - Rosalie, Julian
A1 - Reinsch, Stefan
A1 - Zapala, Pawel
A1 - Michels, Heiner
A1 - Skrotzki, Birgit
T1 - Influence of Mo and B additions in intermetallic near-Fe3Al alloys on microstructure and mechanical properties
N2 - Iron aluminides, already reported in the late 19th century, did not cease to attract the interest of scientists and engineers ever since. Besides good oxidation resistance, low density and resource availability, potentials for hightemperature strengths that compete with high-alloy steels were unlocked by low alloy contents. Still, research on alloy design continues, as alloying usually comes at the price of brittleness in low-temperature regimes. A potential candidate is the quinary Fe–Al–Mo–Ti–B system which is strengthened by solid solution and eutectic borides. It was shown to have good strength and outstanding creep resistance under compressive loading up to elevated temperatures. Although the individual effect of alloy additions is well understood in iron aluminides, little is known about the combined effects of alloying concentrations on microstructure, phase stability and mechanical properties. Therefore a systematic study of two Ti-doped near-Fe3Al alloys with varying contents of Mo (2–4 at.%) and B (0.5–1 at.%) was conducted. In total eight different alloys were fabricated by investment casting into ceramic shell molds. Alloys were characterized and compared by grain size, phase transitions, microstructure evolution as well as elemental compositions and volume fractions of phases. For mechanical characterization, macrohardness and microhardness tests as well as tensile tests at ambient and high tempera tures were conducted. Independent of alloy additions, alloys with 24–25 at.% Al exhibit superior proof strength due to a higher matrix hardness. Decreasing B content generally decreases strength by lower secondary phase fractions which contribute via particle hardening. Reducing Mo content decreases both the solute concentration in the matrix and secondary phase fractions. Surprisingly, strength is similar or even superior to alloys with higher Mo content. Strength relations are discussed with a focus on solid-solution hardening theory and other competing strengthening mechanisms.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585284
DO - https://doi.org/10.1016/j.intermet.2023.108074
VL - 163
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-58528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vecchiato, L.
A1 - Madia, Mauro
A1 - Meneghetti, G.
T1 - Extension of the peak stress method to estimate the fatigue limit of welded joints by means of the cyclic R-curve method
N2 - A new simplified and effective method has been formalised to estimate the Constant Amplitude Fatigue Limit (CAFL) of stress-relieved steel welded joints subjected to uniaxial push–pull loading and failing from the weld toe. Starting from the sharp V-notch assumption of the NSIF approach and the cyclic R-curve of the material in the heat affected zone, the proposed method identifies the CAFL as threshold level of the local stress field at the V-notched weld toe in the uncracked configuration. Such threshold stress field assures the crack arrest at the V-notched weld toe, according to the cyclic R-curve analysis. The method has been validated against experimental results and proved effective for a straightforward assessment of the CAFL of welded joints, as the stable crack propagation analysis of classical fracture mechanics approaches can be avoided.
KW - Cyclic R-curve
KW - Welded joint
KW - Fatigue limit
KW - Peak stress method
KW - Finite element analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581059
DO - https://doi.org/10.1016/j.tafmec.2023.104039
SN - 0167-8442
VL - 127
SP - 1
EP - 19
PB - Elsevier
AN - OPUS4-58105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chang, Yen-Ting
A1 - Sharda, Abhi
A1 - Rosalie, Julian
A1 - Maaß, Robert
A1 - Charpagne, Marie A.
T1 - A bcc refractory high-entropy alloy: the ideal case of smooth plastic flow
N2 - Single crystalline metals exhibit correlated dislocation dynamics, irrespective of lattice system. This collective evolution of dislocation structures is intermittent and scale-free, implying divergent length scales that play a critical role in failure initiation and therefore microstructural design. Here we report on a HfNbTaTiZr refractory high-entropy alloy, that lacks criticality in the collective dislocation response. This unusual behaviour manifests itself in almost quenched-out microplastic stress-strain fluctuations and sluggish dislocation avalanching, otherwise only seen in complex engineering alloys. These findings demonstrate how the high-entropy paradigm can serve as a role model to effectively suppress unwanted plastic fluctuations in metals deformation.
KW - Plasticity
KW - Dislocations
KW - Avalanches
KW - Refractory high-entropy alloys
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630241
DO - https://doi.org/10.1080/21663831.2025.2497860
SN - 2166-3831
SP - 1
EP - 8
PB - Taylor & Francis Group
AN - OPUS4-63024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Avila Calderon, Luis Alexander
A1 - Schriever, Sina
A1 - Hang, Y.
A1 - Olbricht, Jürgen
A1 - Portella, P. D.
A1 - Skrotzki, Birgit
T1 - Creep reference data of single-crystal Ni-based superalloy CMSX-6
N2 - The article presents creep data for the single-crystal, [001]-oriented nickel-based superalloy CMSX-6, tested at a temperature of 980 °C under initial stresses ranging from 140 MPa to 230 MPa. The constant-load creep experiments were performed in accordance with DIN EN ISO 204:2019–4 standard within an ISO 17025 accredited laboratory. A total of 12 datasets are included, each of which includes the percentage creep extension as a function of time. The data series and associated metadata were systematically documented using a data schema specifically developed for creep data of single-crystal Ni-based superalloys. This dataset serves multiple purposes: it can be used to compare with one's own creep test results on similar materials, to verify testing setups (e.g., by replicating tests on the same or comparable materials), to calibrate and validate creep models, and to support alloy development efforts.
KW - NFDI MatWerk
KW - Referenzdaten
KW - Kriechen
KW - CMSX-6
KW - Digitalisierung
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654056
DO - https://doi.org/10.1016/j.dib.2025.112436
VL - 65
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-65405
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Numerical studies of keyhole dynamic behavior during the laser beam welding with an oscillating magnetic field
N2 - The formation of keyhole induced porosity (Process porosity) during laser beam welding (LBW) is mainly associated with the dynamic keyhole behavior. Experimental studies have confirmed that the application of a magnetic field can effectively suppress process porosity. However, there is still no quantitative evidence supporting that this suppression mechanism involves a direct influence of the magnetic field on the keyhole dynamics. In this paper, a novel keyhole reconstruction algorithm is developed and incorporated into a three-dimensional transient multi-physics coupled numerical model to study the dynamic keyhole behavior under the influence of an oscillating magnetic field. This keyhole reconstruction algorithm accurately reproduces the 2D time-averaged keyhole shape, effectively capturing the keyhole tailing and the backward shift of its centroid on the keyhole top. The application of an oscillating magnetic field reduces the keyhole diameter and enhances its stability. The frequency of keyhole collapse is reduced under the influence of a magnetic field. Additionally, the occurrence of keyhole collapses with long duration is significantly reduced in the presence of a magnetic field.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genua, Italy
DA - 22.06.2025
KW - Laser beam welding
KW - Magnetohydrodynamics
KW - Porosity
KW - Numerical simulation
PY - 2025
AN - OPUS4-63645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Short fatigue crack propagation in L-PBF 316L stainless steel
N2 - Fracture mechanics is a key to fatigue assessment in AM metal components. Short fatigue cracks are initiated at defects and pronounced surface roughness intrinsic to AM. The subsequent crack-propagation is strongly influenced by microstructural interactions and the build-up of crack-closure. The aim of the present study is to give an insight into short-crack propagation in AM-metals. Fatigue crack propagation resistance curves were determined experimentally for AISI 316L manufactured by Laser Powder Bed Fusion (L-PBF) which was heat treated at three different temperatures. Differences in the build-up of the fatigue-crack propagation threshold in between the L-PBF specimens and compared to wrought material are due to the residual stress states, a pronounced roughness of the crack-faces in the L-PBF specimens and phase transformation in the vicinity of the crack-tip, resulting in increased crack-closure. This, together with crack-branching found along the crack path, enhances the resistance to the propagation of fatigue cracks.
T2 - ASTM International Conference on Additive Manufacturing 2020
CY - Online meeting
DA - 16.11.2020
KW - Additive Manufacturing
KW - Cyclic R-Curve
KW - Component assessment
KW - L-PBF
KW - 316L
KW - Residual Stress
KW - Fatigue Crack Growth
PY - 2020
AN - OPUS4-51585
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rehmer, Birgit
A1 - Bayram, Faruk
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
T1 - BAM reference data: Temperature-dependent Young's and shear modulus data for additively and conventionally manufactured variants of Ti-6Al-4V
N2 - The elastic properties (Young's modulus, shear modulus) of titanium alloy Ti-6Al-4V were investigated between room temperature and 400 °C in an additively manufactured variant (laser-based directed energy deposition with powder as feedstock, DED-LB/M) and from a conventional process route (hot rolled bar). The moduli were determined using the dynamic resonance method. The data set includes information on processing parameters, heat treatments, microstructure, grain size, specimen dimensions and weight, Young’s and shear modulus as well as their measurement uncertainty.
The dataset was generated in an accredited testing lab using calibrated measuring equipment. The calibrations meet the requirements of the test procedure and are metrologically traceable. The dataset was audited as BAM reference data.
KW - Elastic modulus
KW - Young's modulus
KW - Shear modulus
KW - Additive manufacturing
KW - Ti-6Al-4V
PY - 2023
DO - https://doi.org/10.5281/zenodo.7813732
PB - Zenodo
CY - Geneva
AN - OPUS4-57286
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fareed, Adnan
A1 - Rosalie, Julian
A1 - Kumar, Sourabh
A1 - Kar, S.
A1 - Hickel, Tilmann
A1 - Fähler, S.
A1 - Maaß, Robert
T1 - Constrained incipient phase transformation in Ni-Mn-Ga films: A small-scale design challenge
N2 - Ni-Mn-Ga shape-memory alloys are promising candidates for large strain actuation and magnetocaloric cooling devices. In view of potential small-scale applications, we probe here nanomechanically the stress-induced austenite–martensite transition in single crystalline austenitic thin films as a function of temperature. In 0.5 μm thin films, a marked incipient phase transformation to martensite is observed during nanoindentation, leaving behind pockets of residual martensite after unloading. These nanomechanical instabilities occur irrespective of deformation rate and temperature, are Weibull distributed, and reveal large spatial variations in transformation stress. In contrast, at a larger film thickness of 2 μm fully reversible transformations occur, and mechanical loading remains entirely smooth. Ab-initio simulations demonstrate how an in-plane constraint can considerably increase the martensitic transformation stress, explaining the thickness-dependent nanomechanical behavior. These findings for a shape-memory Heusler alloy give insights into how reduced dimensions and constraints can lead to unexpectedly large transformation stresses that need to be considered in small-scale actuation design.
KW - Shape-memory alloys
KW - Nanoindentation
KW - Incipient plasticity
KW - NiMaGa
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581422
DO - https://doi.org/10.1016/j.matdes.2023.112259
VL - 233
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-58142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Madia, Mauro
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kruse, Julius
A1 - Kannengießer, Thomas
A1 - Wesling, V.
T1 - Influence of ultrasonic-assisted milling on surface integrity of additively manufactured components using MSG processes
N2 - Additive manufacturing (AM) is increasingly used for producing complex metallic components. Subsequent machining is essential to achieve final geometries and surface conditions. The resulting surface integrity, particularly the near-surface residual stress state, plays a crucial role in component performance and fatigue life. This study investigates the potential of ultrasonic-assisted milling (USAM), a hybrid machining process, to improve surface integrity and machinability compared to conventional milling (CM). Three materials were investigated, two difficult-to-cut materials CoCr26Ni9Mo5W and FeNi36 and a low-alloy steel S355J2C. The CoCr26Ni9Mo5W and FeNi36 were additively manufactured via Directed Energy Deposition (DED)-Arc and then machined with varying cutting speeds and feed rates within a Design of Experiments. USAM exhibited enhanced machinability and surface integrity, particularly at low cutting speeds, by reducing cutting forces up to 40% and shifting near-surface residual stresses from tensile to compressive. For S355J2C, USAM reduced cutting forces by approximately 45% and induced near-surface compressive residual stresses up to approximately −700 MPa. Rotating bending tests (DIN50100) show that USAM increases the technical fatigue limit from 307 MPa (CM) to 341 MPa (USAM), i.e., by ∼11%. These findings highlight the advantages of ultrasonic assistance in post-AM machining, offering enhanced fatigue performance and surface quality for various metallic materials.
T2 - 4th International Conference on Advanced Joining Processes 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Ultrasonic-assisted milling
KW - Residual stress
KW - Surface integrity
PY - 2026
DO - https://doi.org/10.1177/14644207261416395
SP - 1
EP - 12
PB - Sage Journals
AN - OPUS4-65682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Han, Ying
A1 - Rosalie, Julian
A1 - Radners, Jan
A1 - Madia, Mauro
A1 - von Hartrott, Philipp
A1 - Skrotzki, Birgit
T1 - Influence of test temperature and test frequency on fatigue life of aluminum alloy EN AW-2618A
N2 - The aluminum alloy EN AW-2618A is a high-strength, precipitation-hardened material developed for applications at elevated temperatures. In service, components such as radial compressor wheels and pistons are exposed to thermal conditions that cause microstructural overaging, leading to mechanical softening. With future exhaust gas turbochargers expected to operate at temperatures up to 230°C and with increasing demands for efficiency and compression ratio, reliable data on fatigue behavior under these conditions is essential but currently lacking. This study aims to close this gap by conducting fully reversed (R = −1) high-cycle fatigue (HCF) tests at room temperature and at 230°C on specimens in an overaged condition (1000 h at 230°C), simulating the degradation that occurs in service due to the coarsening of the strengthening S-phase. Additionally, the influence of test frequency on fatigue performance is investigated.
KW - High-cycle fatigue
KW - EN AW-2618A
KW - High-temperature
KW - Recipitation hardening
KW - Overaging
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658655
DO - https://doi.org/10.1002/adem.202503187
SN - 1527-2648
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gook, S.
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Verfahren zum fehlerfreien Laserstrahl-Hybridschweißen von gechlossenen Rundnähten
N2 - In diesem Beitrag werden Ergebnisse der Untersuchungen eines Verfahrens zum fehlerfreien Laserstrahl Hybridschweißen von geschlossenen Rundnähten vorgestellt. Das Verfahren zielt auf die Vermeidung von Schweißimperfektionen im Überlappbereich einer laserstrahlhybridgeschweißten Rundnaht. Eine Strategie der Prozessführung beim Schließen der Rundnaht wurde entwickelt, mit der ein fehlerfreier Überlappbereich durch die Kontrolle der Erstarrungsbedingungen am Schweißnahtende erreicht wird. Die kontrollierte Wärmeführung wird durch eine Anpassung der Parameter von beiden beteiligten Schweißprozessen, dem Laserstrahl- sowie MSG Schweißprozess realisiert. Experimentelle Untersuchungen wurden an 12 mm bis 15 mm dicken Rohrabschnitten durchgeführt. Der Einfluss von Prozessparametern wie der Laserleistungsrampe und Rampenzeit, der Veränderung des Abbildungsmaßstabes und der Defokussierung des Laserstrahls auf die Erstarrungsbedingungen am Ende der Rundnaht wurde untersucht, um eine optimale Strategie zum Herausführen der Prozessenergie zu finden. Im Rahmen der experimentellen Untersuchungen konnte gezeigt werden, dass eine Defokussierung des Laserstrahls im Bereich zwischen 60 mm und 100 mm über einen kurzen Auslaufbereich der Naht von ca. 15 mm zu einer deutlich besseren Nahtausbildung im Überlappbereich führte. Es konnte eine günstige kelchförmige Schweißnahtform ohne eine Tendenz zur Rissbildung erzielt werden. Die Laseroptik mit motorisch angesteuertem Linsensystem ermöglichte dabei eine Vergrößerung des Laserstrahldurchmessers ohne eine Veränderung der Position des MSG-Lichtbogens relativ zur Bauteiloberfläche.
T2 - DVS Congress 2020
CY - Online meeting
DA - 14.09.2020
KW - Defokussierung
KW - Endkrater
KW - Laser-Hybridschweißen
KW - Rundnaht
KW - Überlappbereich
PY - 2020
SN - 978-3-96144-098-6
VL - 365
SP - 855
EP - 860
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-51324
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Hybrid Laser-Arc Welding of Thick-Walled, Closed, Circumferential Pipe Welds
N2 - The application of hybrid laser-arc welding (HLAW) for joining closed circumferential welds is a challenge due to the high risk of forming a defective overlap area with a shrinkage void or solidification cracks in the material thickness. A series of HLAW experiments were performed to understand the development of a faulty overlap area when closing the circumferential weld. Welding trials on flat specimens and pipe segments were supported by numerical analyses in which the thermomechanical behavior of the welds in the overlap area was investigated. Different process control strategies were tested, including variations in defocusing levels and the overlap length. The newly developed HLAW head, including laser optics with a motor-driven collimation system, made it possible to defocus the laser beam during welding without disturbing the stability of the welding process. High-level defocusing of the laser beam of more than 40 mm relative to the specimen surface with a resulting beam diameter of > 2.9 mm, and in combination with a short overlap length of 15 mm, was promising with respect to the formation of a desired cup-shaped weld profile that is resistant to solidification cracks.
KW - Hybrid Laser-Arc Welding
KW - Thick-Walled Steel
KW - High-Power Welding
KW - Crater
KW - Pipe Welding
PY - 2022
DO - https://doi.org/10.29391/2022.101.002
SN - 0043-2296
VL - 101
IS - 1
SP - 15
EP - 26
PB - American Welding Society
CY - New York, NY
AN - OPUS4-55508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, S.
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
A1 - Lichtenthäler, F.
A1 - Stark, M.
T1 - Multiple-wire submerged arc welding of high-strength fine-grained steels
N2 - Ensuring the required mechanical-technological properties of welds is a critical issue in the application of multi-wire submerged arc welding processes for welding high-strength fine-grained steels. Excessive heat input is one of the main causes for microstructural zones with deteriorated mechanical properties of the welded joint, such as a reduced notched impact strength and a lower structural robustness. A process variant is proposed which reduces the weld volume as well as the heat input by adjusting the welding wire configuration as well as the energetic parameters of the arcs, while retaining the advantages of multiwire submerged arc welding such as high process stability and production speed.
KW - Submerged arc welding
KW - High-strength fine-grained steels
KW - Mechanical properties of the joints
KW - Energy parameters of the arc
PY - 2022
DO - https://doi.org/10.37434/tpwj2022.01.02
SN - 0957-798X
IS - 1
SP - 9
EP - 13
PB - Paton Publishing House
CY - Kiev
AN - OPUS4-54701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Batahgy, A.
A1 - Saiyah, A.
A1 - Khafagi, S.
A1 - Gumenyuk, Andrey
A1 - Gook, S.
A1 - Rethmeier, Michael
T1 - Shielded metal arc welding of 9%Ni steel using matching ferritic filler metal
N2 - Motivated by the tensile strength loss of 9%Ni steel arc welded joints made using Ni-based austenitic filler metals, the feasibility of maintaining the tensile strength using matching ferritic filler metal has been demonstrated. In comparison with shielded metal arc welded joint made using Ni-based austenitic electrode ENiCrMo-6, higher tensile strength comparable to that of the base metal was obtained using matching ferritic electrode. Besides, sufficient impact toughness energies with much lower mismatch were obtained for weld metal and heat-affected zone.
Welded joint with a lower mechanical mismatching is of considerable importance for achieving acceptable combination of tensile strength and impact toughness.Abetter combination of These mechanical properties is ensured by applying a post weld heat treatment.
KW - Mechanical mismatching
KW - Mechanical properties
KW - Microstructure
KW - Austenitic welding electrode
KW - Matching ferritic welding electrode
PY - 2020
DO - https://doi.org/10.1080/13621718.2020.1846936
SN - 1362-1718
SP - 1
EP - 7
PB - Taylor & Francis
AN - OPUS4-51835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jokisch, T.
A1 - Gook, S.
A1 - Marko, A.
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laserstrahlschweißen additiv gefertigter Bauteile: Einsetzbarkeit bestehender Bewertungsvorschriften
N2 - Bei der additiven Fertigung im Pulverbett ist die Bauteilgröße durch den Bauraum begrenzt. Das Verbindungsschweißen additiv gefertigter Teile bietet eine Möglichkeit diese Größenbegrenzung aufzuheben. Aufgrund des spezifischen Spannungs- und Gefügezustands im additiv aufgebauten Teil ist jedoch unklar, inwiefern bestehende Bewertungsvorschriften des Verbindungsschweißens auch für Schweißnähte an additiv gefertigten Bauteilen geeignet sind. Dies wird anhand des Laserstrahlschweißens additiv gefertigter Rohrverbindungen untersucht. Die Schweißnähte werden mittels visueller Prüfung, metallografischer Untersuchungen sowie Computertomografie ausgewertet. Die festgestellten Fehlerarten sind vergleichbar zu konventionellen Bauteilen. Dies ist ein Indikator dafür, dass bestehende Bewertungsvorschriften die möglichen auftretenden Defekte auch für Schweißnähte an additiven Bauteilen abbilden.
KW - Schweißunregelmäßigkeiten
KW - Additive Fertigung
KW - Laserstrahlschweißen
KW - Schweißeignung
PY - 2021
VL - 73
IS - 3
SP - 132
EP - 137
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-53575
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jokisch, T.
A1 - Gook, S.
A1 - Marko, A.
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser beam welding of additive manufactured components: Applicability of existing valuation regulations
N2 - With additive manufacturing in the powder bed, the component size is limited by the installation space. Joint welding of additively manufactured parts offers a possibility to remove this size limitation. However, due to the specific stress and microstructure state in the additively built material, it is unclear to what extent existing evaluation rules of joint welding are also suitable for welds on additive components. This is investigated using laser beam welding of additively manufactured pipe joints. The welds are evaluated by means of visual inspection, metallographic examinations as well as computed tomography. The types of defects found are comparable to conventional components. This is an indicator that existing evaluation regulations also map the possible defects occurring for weld seams on additive components.
KW - Weld imperfections
KW - Additive manufacturing
KW - Weldability
KW - Laser welding
PY - 2022
VL - 2
SP - 109
EP - 113
PB - DVS Media GmbH
AN - OPUS4-56374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marquardt, R.
A1 - Gook, S.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Handgeführtes Laserstrahlschweissen am T-Stoss eines niedrig legierten Stahls
N2 - Das handgeführte Laserstrahlschweißen gewinnt in der Industrie zunehmend an Bedeutung, da die hohe Produktivität und die einfache Handhabung Unternehmen wirtschaftliche Vorteile bieten. Derzeit ist der Einsatz in der Industrie jedoch auf Teile mit ästhetischen Anforderungen beschränkt, die häufig aus hochlegiertem Stahl bestehen. Um das Handschweißen mit Laserstrahl auch für Bauteile aus kostengünstigen Stähle mit guten mechanischen Eigenschaften einsetzen zu können, untersucht diese Studie den Einfluss des Schutzgases auf die Porosität am mikrolegierten Stahl HX340LAD mit einer Dicke von 1,5 mm. Getestet wurden die Gase Argon, Stickstoff, CO2 sowie Mischungen aus Argon und CO2 an T-Stöße mit Zusatzdraht. Die Qualifizierung der Porosität erfolgte gemäß DIN EN ISO 13919-1 an Querschliffen als auch mittels Röntgenuntersuchung. Die Ergebnisse zeigen, dass für diesen Stahl die Bewertungsgruppe B mittels CO2 als Schutzgas erreicht werden kann. Stickstoff führt zu Gruppe C, Argon zu D.
KW - Handgeführtes Laserstrahlschweißen, HHLW, Stahl, Laser
KW - HHLW
KW - Stahl
KW - Laser
PY - 2025
SP - 22
EP - 25
PB - Schweizerischer Verein für Schweisstechnik SVS
AN - OPUS4-65041
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
T1 - Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support
N2 - One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds.
T2 - X International Conference «Beam Technologies & Laser Application
CY - Online meeting
DA - 20.09.2021
KW - Plasma-cutting
KW - Hybrid laser-arc welding
KW - Thick-walled steel
KW - Edge quality
KW - Gap bridgeability
KW - Misalignment of the edges
PY - 2021
AN - OPUS4-53920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design
N2 - My talk covered, among other things, robust data generation for machine learning. It showed how heuristics can be used within machine learning models and how they might also be extracted from machine learning models. Beyond this, I showed an automated pipeline for training machine learning potentials.
T2 - Workshop on AI in Sustainable Materials Science
CY - Düsseldorf, Germany
DA - 27.01.2026
KW - Automation
KW - Digitalisation
KW - Materials Design
KW - Thermal Conductivity
KW - Chemical bonding
KW - Materials Acceleration Platforms
PY - 2026
AN - OPUS4-65427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automation in Computational Materials Science
N2 - This lecture illustrated the current state of automation in the field of computational materials science based on recent examples from my research.
T2 - NOA Lecture Series FSU Jena
CY - Jena, Germany
DA - 02.11.2021
KW - Data analysis
KW - Machine learning
KW - High-throughput computations
PY - 2021
AN - OPUS4-54089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash Ashok
T1 - Linking quantum chemical bonding analysis descriptors to material property predictions
N2 - Examining the bonding between their constituent atoms in crystalline materials has played a vital role in understanding material properties. For instance, low thermal conductivity in materials is typically attributed to its anharmonicity, which has been reported to arise from strong antibonding interactions and local environment distortions. Employing an automated for bonding analysis that we developed, we have generated for ~13000 crystalline compounds such bonding analysis data. To create new descriptors from these data automatically, we extended our package LobsterPy. The curated descriptors span different types, including statistical representations of bonding characteristics for traditional ML algorithms (e.g., random forests), textual descriptions for large language models (LLMs), and structure graphs for graph neural networks (GNNs). These descriptors are then tested by employing them in several state-of-the-art ML algorithms and architectures to predict the mechanical, vibrational, and thermal properties of crystalline materials. Through this work, we are not only able to demonstrate how one can enhance the model’s predictive accuracy by incorporating quantum chemical bonding-based descriptors alongside typical composition and structure-based descriptors, but it also aids in uncovering relationships between bonding and materials properties on a larger scale, which was not possible before.
T2 - AI MSE 2025
CY - Bochum, Germany
DA - 18.11.2025
KW - Bonding analysis
KW - Machine learning
KW - Materials Descriptors
KW - Force constants
PY - 2025
AN - OPUS4-64791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
T1 - Werkstoffsichere Dickblechschweißung und KI
N2 - Der Vortrag zeigt, welche Herausforderungen beim Schweißen sogenannter Dickblechverbindungen bestehen und welche Strategien zur Lösung genutzt werden können. Ansätze zur Fehlerprävention werden vorgestellt. Es wird dargestellt, wie KI-basierte Methoden die Fehlererkennung erleichtern. Letztlich werden Potentiale zur effizienten Fehlerbeseitigung aufgezeigt und der Anwendernutzen herausgestellt.
T2 - Mitgliederversammlung der Forschungsvereinigung Stahlanwendung e. V.
CY - Essen, Germany
DA - 17.12.2025
KW - UP-Schweißen
KW - Eigenspannungen
KW - Künstliche Intelligenz
KW - Reparatur
PY - 2025
AN - OPUS4-65210
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation of the Application of a C-ring Geometry to validate the Stress Relief Heat Treatment Simulation of Additive Manufactured Austenitic Stainless Steel Parts via Displacement
N2 - Directed energy deposition is a metal additive manufacturing process that builds parts by joining material in a layer-by-layer fashion on a substrate. Those parts are exposed to rapid thermo-cycles which cause steep stress gradients and the layer-upon-layer manufacturing fosters an anisotropic microstructure, therefore stress relief heat treatment is necessary. The numerical simulation can be used to find suitable parameters for the heat treatment and to reduce the necessary efforts to perform an effective stress relieving. Suitable validation Experiments are necessary to verify the results of the numerical simulation.
In this paper, a 3D coupled thermo-mechanical model is used to simulate the heat treatment of an additive manufactured component to investigate the application of a C-ring geometry for the distortion-based validation of the numerical simulation.
Therefore, the C-ring samples were 3D scanned using a structured light 3D scanner to quantify the distortion after each process step.
KW - Additive manufacturing
KW - Directed energy deposition
KW - Laser
KW - Heat treatment
KW - Numerical simulation
PY - 2020
DO - https://doi.org/10.3139/105.110417
VL - 75
IS - 4
SP - 248
EP - 259
PB - Carl Hanser Verlag
AN - OPUS4-51318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust data generation, heuristics and machine learning for designing sustainable materials
N2 - Despite advances in computational materials design, simulating large systems—such as defects, interfaces, or amorphous states—with quantum-chemical accuracy remains a major challenge.[1] Machine learning (ML) methods are emerging as powerful tools to overcome these limitations, enabling scalable and accurate modeling beyond traditional quantum-chemical approaches.[2] They also open new avenues for discovering non-toxic, earth-abundant alternatives to existing materials and can be combined with self-driving labs. [3] There are nowadays robust data generation strategies that underpin the development and benchmarking of ML models. [4,5]atomate2 I will focus on such strategies for quantum-chemical bonding analysis and ML interatomic potentials in my talk. Quantum-chemical bonding descriptors can be effectively used in ML models to predict phononic properties. [6] ML interatomic potentials offer a powerful approach for predicting energies, forces, and stresses—but their performance hinges on high-quality training data. Our automated framework, autoplex, enables diverse and scalable training workflows, from random structure searches for general-purpose models to phonon-aware pipelines for high-accuracy predictions.[7] While quantum chemistry excels in many domains, properties like magnetism and synthesizability remain elusive. Here, heuristics or leveraging experimental data for ML offer promising alternatives.[8,9]
T2 - Advanced Materials Safety 2025
CY - Dresden, Germany
DA - 04.11.2025
KW - Nano Particles
KW - Machine Learning
KW - Automation
KW - Materials Design
KW - Sustainability
KW - Material Safety
PY - 2025
AN - OPUS4-64599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bustamante, Joana
A1 - Naik, Aakash
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - George, Janine
T1 - Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study.
N2 - This repository includes raw data for bonding analysis and lattice thermal conductivity using MLIP-MACE-MP03b, supporting the manuscript “Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study”
KW - DFT
KW - LOBSTER
KW - Lattice thermal conductivity
KW - MLIP
PY - 2025
DO - https://doi.org/10.5281/zenodo.17397456
PB - Zenodo
CY - Geneva
AN - OPUS4-64674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pérez Blanes, H.
A1 - Ghiasi, P.
A1 - Sandkühler, J.
A1 - Yesilcicek, Yasemin
A1 - Pentzien, Simone
A1 - Conradi, Andrea
A1 - Prinz, Carsten
A1 - Al-Sabbagh, Dominik
A1 - Thünemann, Andreas
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation
N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts.
KW - Multi-principal element alloys
KW - Chemically Complex Materials
KW - CCMat
KW - Electrocatalysis
KW - Carbon dioxide reduction
KW - Pulsed laser ablation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594018
DO - https://doi.org/10.1016/j.jmrt.2023.05.143
VL - 24
SP - 9434
EP - 9440
PB - Elsevier BV
AN - OPUS4-59401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design
N2 - My talk covered, among other things, robust data generation for machine learning. It showed how heuristics can be used within machine learning models and how they might also be extracted from machine learning models. Beyond this, I showed an automated pipeline for training machine learning potentials.
T2 - Seminar Gruppe Stephan Roche
CY - Barcelona, Spain
DA - 22.01.2026
KW - Automation
KW - Machine Learning
KW - Materials Acceleration Platforms
KW - Thermal Conductivity
KW - Phonons
KW - Bonding Analysis
PY - 2026
AN - OPUS4-65428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strobl, Dominic
T1 - Real-time Bead-on-Plate weld Simulation for Wire Arc Additive Manufacturing using Reduced Order modelling coupled with stochastic model Calibration
N2 - Numerical simulations are essential in predicting the behavior of systems in many engineering fields and industrial sectors. The development of accurate virtual representations of actual physical products or processes (also known as digital twins) allows huge savings in cost and resources. In fact, digital twins would allow reducing the number of real, physical prototypes, tests, and experiments, thus also increasing the sustainability of production processes and products’ lifetime. Standard numerical methods fail in providing real time simulations, especially for complex processes such as additive manufacturing applications.
This work aims to use a reduced order model for efficient wire arc additive manufacturing simulations, calibrations and real-time process control. Model reduction, e.g. the proper generalized decomposition [1,2] method, is a popular concept to decrease the computational effort. A new mapping approach [3] was applied to simulate a moving heat source with the proper generalized decomposition. Using this procedure even complex models can be simulated in real-time. The physical model is later on calibrated with the use of a stochastic model updating process and the reduced order model, leading to an optimized real-time simulation.
In this contribution, a proper generalized decomposition model for a bead-on-plate wire arc additive manufacturing is presented. It is also coupled with a stochastic model updating process identifying the heat source characteristics as well as the boundary conditions of the transient thermal problem, whereas the heat source shape is simulated using a Goldak heat source
T2 - 15th World Congress on Computational Mechanics (WCCM-XV)
CY - Yokohama, Japan
DA - 31.07.2022
KW - Wire arc additive manufacturing
KW - Reduced order modelling
KW - Model calibration
PY - 2022
AN - OPUS4-55576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holzer, Marco
T1 - Glass fracture surface energy calculated from crystal structure and bond-energy data
N2 - Enhancing the fracture toughness is still one of the major challenges in the field of oxide glasses. To screen different glass systems for promising candidates, a theoretical expression for the fracture surface energy, G, linked to the fracture toughness, KIc, is thus of interest. Extending our earlier work on nucleation and surface energies [1], we present a simple approach for predicting the fracture surface energy of oxide glasses, G using readily available crystallographic structure data and diatomic bond energies. The proposed method assumes that G of glass equals the surface fracture energy of the weakest fracture (cleavage) plane of the isochemical crystal. For non-isochemically crystallizing glasses, an average G is calculated from the weighed fracture energy data of the constitutional crystal phases according to Conradt [2]. Our predictions yield good agreement with the glass density- and chemical bond energy-based prediction model of Rouxel [3] and with experimentally obtained G values known at present.
[1] C. Tielemann, S. Reinsch, R. Maass, J. Deubener, R. Müller, J. Non-Cryst. Solids 2022, 14, 100093
[2] R. Conradt, J. Non-Cryst. Solids 2004, 345-346, 16
[3] R., Tanguy, Scripta Materialia 2017, 109-13, 137
T2 - DPG Spring Meeting of the Condensed Matter Section
CY - Dresden, Germany
DA - 26.03.2023
KW - Fracture Toughness
KW - Oxide Glasses
KW - Surface Energy
PY - 2023
AN - OPUS4-58414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grandel, Jonas
T1 - Fine-tuning universal interatomic potentials for phonon properties without catastrophic forgetting
N2 - Accurate phonon predictions are essential for evaluating material stability and thermal behavior. Traditional DFT-based methods are computationally intensive, driving interest in faster, machine-learning-based alternatives. In this work, we fine-tune the machine learning interatomic potential MACE-MP-0b3 (https://arxiv.org/abs/2401.00096) to improve the prediction of harmonic phonons and thermal properties.
A key challenge is the need for highly accurate force calculations. While fine-tuning can enhance phonon accuracy, it may reduce generalizability to other properties.
Despite this, our study shows that fine-tuned models can accurately predict phonon properties (including renormalization of imaginary phonons) at the same time as volume-dependent properties like the bulk modulus. We fine-tune the base model using small sets of rattled structures and introduce a novel fine-tuning method, benchmarking it against existing techniques. These results suggest that refined MACE-based universal potentials are a promising path for efficient and accurate phonon modeling. All implementations are included in the equitrain training code (https://github.com/BAMeScience/equitrain).
T2 - Psi-k Konferenz
CY - Lausanne, France
DA - 25.08.2025
KW - Machine Learning
KW - MACE
KW - Phonon
KW - Thermal properites
PY - 2025
AN - OPUS4-64010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ganose, Alex M.
A1 - Sahasrabuddhe, Hrushikesh
A1 - Asta, Mark
A1 - Beck, Kevin
A1 - Biswas, Tathagata
A1 - Bonkowski, Alexander
A1 - Bustamante, Joana
A1 - Chen, Xin
A1 - Chiang, Yuan
A1 - Chrzan, Daryl C.
A1 - Clary, Jacob
A1 - Cohen, Orion A.
A1 - Ertural, Christina
A1 - Gallant, Max C.
A1 - George, Janine
A1 - Gerits, Sophie
A1 - Goodall, Rhys E. A.
A1 - Guha, Rishabh D.
A1 - Hautier, Geoffroy
A1 - Horton, Matthew
A1 - Inizan, T. J.
A1 - Kaplan, Aaron D.
A1 - Kingsbury, Ryan S.
A1 - Kuner, Matthew C.
A1 - Li, Bryant
A1 - Linn, Xavier
A1 - McDermott, Matthew J.
A1 - Mohanakrishnan, Rohith Srinivaas
A1 - Naik, Aakash A.
A1 - Neaton, Jeffrey B.
A1 - Parmar, Shehan M.
A1 - Persson, Kristin A.
A1 - Petretto, Guido
A1 - Purcell, Thomas A. R.
A1 - Ricci, Francesco
A1 - Rich, Benjamin
A1 - Riebesell, Janosh
A1 - Rignanese, Gian-Marco
A1 - Rosen, Andrew S.
A1 - Scheffler, Matthias
A1 - Schmidt, Jonathan
A1 - Shen, Jimmy-Xuan
A1 - Sobolev, Andrei
A1 - Sundararaman, Ravishankar
A1 - Tezak, Cooper
A1 - Trinquet, Victor
A1 - Varley, Joel B.
A1 - Vigil-Fowler, Derek
A1 - Wang, Duo
A1 - Waroquiers, David
A1 - Wen, Mingjian
A1 - Yang, Han
A1 - Zheng, Hui
A1 - Zheng, Jiongzhi
A1 - Zhu, Zhuoying
A1 - Jain, Anubhav
T1 - Atomate2: Modular workflows for materials science
N2 - High-throughput density functional theory (DFT) calculations have become a vital element of computational materials science, enabling materials screening, property database generation, and training of “universal” machine learning models. While several software frameworks have emerged to support these computational efforts, new developments such as machine learned force fields have increased demands for more flexible and programmable workflow solutions. This manuscript introduces atomate2, a comprehensive evolution of our original atomate framework, designed to address existing limitations in computational materials research infrastructure. Key features include the support for multiple electronic structure packages and interoperability between them, along with generalizable workflows that can be written in an abstract form irrespective of the DFT package or machine learning force field used within them. Our hope is that atomate2's improved usability and extensibility can reduce technical barriers for high-throughput research workflows and facilitate the rapid adoption of emerging methods in computational material science.
KW - Automation
KW - Materials design
KW - DFT workflows
KW - Phonons
KW - Thermal conductivity
KW - Bonding analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635759
DO - https://doi.org/10.1039/d5dd00019j
SN - 2635-098X
SP - 1
EP - 30
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-63575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical studies of process porosity suppression by magnetohydrodynamic technology during the laser beam welding of aluminum alloy
N2 - Magnetohydrodynamic (MHD) technology is acknowledged as a promising method for mitigating the porosity defects in laser-welded joints of aluminum alloys. A transient 3D multi-physical numerical model of laser beam welding (LBW), coupled with the MHD and oscillating metal vapor plume model, is developed to study the suppression mechanisms of process porosity by an external magnetic field. The experimental results demonstrate that the porosity ratio is reduced by 93.5 % as the oscillating magnetic field is applied. This significant reduction confirms the effectiveness of the MHD technology in suppressing porosity defects. A downward time-averaged Lorentz force is induced in the weld pool, which affects the fluid flow pattern and the weld pool profile. The change of the flowing pattern in the weld pool by the magnetic field does not always have a positive effect on the porosity suppression. In addition, an analytical model shows that the bubble escape window is expanded by 62 % under the effect of the oscillating magnetic field. The additional upward velocity provided by the electromagnetic expulsive force on the bubbles and the change of weld pool profile are considered favorable factors in eliminating the porosity defects. The numerical and analytical model developed for analyzing the bubble escape window have been validated by experimental results.
KW - Laser beam welding
KW - Aluminum alloy
KW - Process porosity defects
KW - Magnetohydrodynamic technology
KW - Bubble escape
KW - Numerical simulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637642
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2025.127525
SN - 0017-9310
VL - 253
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-63764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, Max
A1 - Yang, Keke
A1 - Meschut, Gerson
A1 - Rethmeier, Michael
T1 - Occurrence and avoidance of liquid metal embrittlement in resistance spot welding of springback-afflicted deep-drawn components
N2 - This study investigates the occurrence and mitigation of liquid metal embrittlement occurring during resistance spot welding in deep-drawn automotive components, specifically focusing on an S-Rail made from advanced high-strength steel. A simulation-based liquid metal embrittlement risk criterion based on local major component stresses was established and used to quantify and compare liquid metal embrittlement risks between different tests. Experimental and numerical analyses were conducted, revealing that springback significantly impacts liquid metal embrittlement formation. Adjustments in electrode geometry and hold time post-welding were found to mitigate liquid metal embrittlement risks. The effects of stack-up configuration and related parameter settings on liquid metal embrittlement occurrence were identified and liquid metal embrittlement was effectively prevented across both stack-up configurations. These findings advance the understanding of liquid metal embrittlement mechanisms and provide practical approaches to enhance the spot weld quality in AHSS-based body-in-whites.
KW - Liquid metal embrittlement
KW - Crack
KW - Advanced high-strength steels
KW - Resistance spot welding
KW - Weld current
KW - Heat input
KW - Simulation
KW - Springback
KW - Deep drawing
KW - S-Rail
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636577
DO - https://doi.org/10.1177/13621718251340452
SN - 1362-1718
SP - 1
EP - 9
PB - SAGE Publications
AN - OPUS4-63657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Multi-refining effects of an AC electromagnetic field on the microstructure in AA5754 laser beam welding
N2 - Fine-grain structure is beneficial to the mechanical properties of the joint. Different kinds of grain and sub-grain structures refined by magnetic field during laser beam welding of AA5754 aluminum alloy are analyzed in this manuscript, and the influences of different magnetic field parameters (magnetic flux density and frequency) in these refining effects are also studied. Using the scanning electron microscope (SEM), the sub-grain structure near the fusion line was obtained, and it was found that the branching promotion and branches refinement can be achieved by the magnetic field. The branches become finer with the magnetic flux density or frequency increases, and this effect is stronger in the dendritic region than in the equiaxed region. The results of electron backscatter diffraction (EBSD) in the equiaxed region show that a high-frequency magnetic field can greatly reduce the average grain size, while a low-frequency one has little effect. A phenomenological nucleation model based on dendrite fragmentation theory was established, and it was introduced into the phase field model to analyze the equiaxed grains evolution process. In addition, another refinement mechanism was also observed. The periodic solidification pattern caused by the unstable solidification in the molten pool can refine the grains, and the magnetic field promotes this kind of grain refinement by promoting the solidification period.
KW - Laser beam welding
KW - Magnetic field
KW - Aluminum alloy
KW - Crystal branch development
KW - Periodic solidification pattern
KW - Grain refinement
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637222
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2025.127509
SN - 0017-9310
VL - 252
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-63722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riebesell, Janosh
A1 - Goodall, Rhys E. A.
A1 - Benner, Philipp
A1 - Chiang, Yuan
A1 - Deng, Bowen
A1 - Ceder, Gerbrand
A1 - Asta, Mark
A1 - Lee, Alpha A.
A1 - Jain, Anubhav
A1 - Persson, Kristin A.
T1 - A framework to evaluate machine learning crystal stability predictions
N2 - The rapid adoption of machine learning in various scientific domains calls for the development of best practices and community agreed-upon benchmarking tasks and metrics. We present Matbench Discovery as an example evaluation framework for machine learning energy models, here applied as pre-filters to first-principles computed data in a high-throughput search for stable inorganic crystals. We address the disconnect between (1) thermodynamic stability and formation energy and (2) retrospective and prospective benchmarking for materials discovery. Alongside this paper, we publish a Python package to aid with future model submissions and a growing online leaderboard with adaptive user-defined weighting of various performance metrics allowing researchers to prioritize the metrics they value most. To answer the question of which machine learning methodology performs best at materials discovery, our initial release includes random forests, graph neural networks, one-shot predictors, iterative Bayesian optimizers and universal interatomic potentials. We highlight a misalignment between commonly used regression metrics and more task-relevant classification metrics for materials discovery. Accurate regressors are susceptible to unexpectedly high false-positive rates if those accurate predictions lie close to the decision boundary at 0 eV per atom above the convex hull. The benchmark results demonstrate that universal interatomic potentials have advanced sufficiently to effectively and cheaply pre-screen thermodynamic stable hypothetical materials in future expansions of high-throughput materials databases.
KW - Machine Learning
KW - Interatomic Potentials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637139
DO - https://doi.org/10.1038/s42256-025-01055-1
SN - 2522-5839
VL - 7
IS - 6
SP - 836
EP - 847
PB - Springer Science and Business Media LLC
AN - OPUS4-63713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amariamir, Sasan
A1 - George, Janine
A1 - Benner, Philipp
T1 - SynCoTrain: a dual classifier PU-learning framework for synthesizability prediction
N2 - Material discovery is a cornerstone of modern science, driving advancements in diverse disciplines from biomedical technology to climate solutions. Predicting synthesizability, a critical factor in realizing novel materials, remains a complex challenge due to the limitations of traditional heuristics and thermodynamic proxies. While stability metrics such as formation energy offer partial insights, they fail to account for kinetic factors and technological constraints that influence synthesis outcomes. These challenges are further compounded by the scarcity of negative data, as failed synthesis attempts are often unpublished or context-specific. We present SynCoTrain, a semi-supervised machine learning model designed to predict the synthesizability of materials. SynCoTrain employs a co-training framework leveraging two complementary graph convolutional neural networks: SchNet and ALIGNN. By iteratively exchanging predictions between classifiers, SynCoTrain mitigates model bias and enhances generalizability. Our approach uses Positive and Unlabeled (PU) learning to address the absence of explicit negative data, iteratively refining predictions through collaborative learning. The model demonstrates robust performance, achieving high recall on internal and leave-out test sets. By focusing on oxide crystals, a well-characterized material family with extensive experimental data, we establish SynCoTrain as a reliable tool for predicting synthesizability while balancing dataset variability and computational efficiency. This work highlights the potential of co-training to advance high-throughput materials discovery and generative research, offering a scalable solution to the challenge of synthesizability prediction.
KW - Synthesizability
KW - Accelerated Materials Design
KW - Materials Acceleration Platforms
KW - Materials Design
KW - Materials Discovery
KW - Co-training
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637907
DO - https://doi.org/10.1039/D4DD00394B
SN - 2635-098X
VL - 4
IS - 6
SP - 1437
EP - 1448
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Ueltzen, Katharina
A1 - Naik, Aakash A.
A1 - Ertural, Christina
A1 - Benner, Philipp
A1 - George, Janine
T1 - Can simple exchange heuristics guide us in predicting magnetic properties of solids?
N2 - A popular heuristic derived from the Kanamori-Goodenough-Anderson rules of superexchange connects bond angles and magnetism in certain transition metal compounds. We evaluate the fulfillment of this heuristic on databases of magnetic structures. The heuristic is partly satisfied in magnetic structures from experiment, and exceptions can be rationalized. We further show that incorporating this heuristic into machine learning models for magnetism improves the prediction.
KW - Magnetism
KW - Transition Metal Compounds
KW - Materials Design
KW - Sustainable Materials Design
KW - Machine Learning
KW - Materials Understanding
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639290
DO - https://doi.org/10.26434/chemrxiv-2025-xj84d
VL - Version 1
SP - 1
EP - 43
AN - OPUS4-63929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Janssen, Jan
A1 - George, Janine
A1 - Geiger, Julian
A1 - Bercx, Marnik
A1 - Wang, Xing
A1 - Ertural, Christina
A1 - Schaarschmidt, Joerg
A1 - Ganose, Alex M.
A1 - Pizzi, Giovanni
A1 - Hickel, Tilmann
A1 - Neugebauer, Joerg
T1 - A Python workflow definition for computational materials design
N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron.
KW - Automation
KW - Workflow
KW - Materials Design
KW - Multi-scale simulation
KW - Digitalization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632328
DO - https://doi.org/10.48550/arXiv.2505.20366
SP - 1
EP - 12
AN - OPUS4-63232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Fasselt, Janek Maria
A1 - Klötzer-Freese, Christian
A1 - Kruse, Tobias
A1 - Kleba-Ehrhardt, Rafael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Recycling nickel aluminium bronze grinding chips to feedstock for directed energy deposition via impact whirl milling: Investigation on processability, microstructure and mechanical properties
N2 - During the production of ship propellers, considerable quantities of grinding chips from nickel aluminium bronze are produced. This paper examines the mechanical comminution of such chips via impact whirl milling and the utilization of two chip-powder batches as feedstock for a laser-based directed energy deposition process. The materials are characterized via digital image analysis, standardized flowability tests, scanning electron microscopy and energy dispersive X-ray spectroscopy and are compared to conventional, gas atomized powder. The specimens deposited via directed energy deposition are analyzed for density, hardness and microstructure and tensile properties for vertical and horizontal build up directions are compared. At elevated mill rotation speeds, the comminution with impact whirl milling produced rounded particles, favorable flow properties and particle size distribution, making them suitable to deposit additive specimens. The microstructure exhibited characteristic martensitic phases due to the high cooling rates of the additive manufacturing process. The presence of ceramic inclusions was observed in both the powder and on the tensile fracture surfaces, partly impairing the mechanical properties. However, specimens in the vertical build-up direction (Z) showed competitive tensile results, with 775 MPa in tensile strength, 455 MPa in yield strength and 12.6 % elongation at break. The findings of this study indicate that recycling of machining chips to additive manufacturing feedstock can be a viable option for reducing material costs and environmental impact.
KW - Nickel aluminium bronze
KW - Grinding chips
KW - Recycling
KW - Directed energy deposition
KW - Material characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633442
DO - https://doi.org/10.1016/j.addma.2025.104804
SN - 2214-8604
VL - 105
SP - 1
EP - 9
PB - Elsevier BV
AN - OPUS4-63344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Klement, Oliver
A1 - Sander, Steffen
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Recycling of Stainless Steel Milling Chips for Additive Manufacturing: A Three-Stage Comminution Approach Using a Fine Impact Mill
N2 - The production of conventional metal powders for additive manufacturing process is energy intensive and costly. This study introduces a sustainable alternative by recycling stainless steel milling chips as feedstock for laser-powder directed energy deposition. The recycling process employs a three-stage mechanical comminution method utilizing a fine impact mill UPZ100 from Hosokawa Alpine AG. Characterization of the resulting powders is conducted through particle morphology analysis, flowability tests, and mechanical property assessments. The chip-derived powders exhibit comparable aspect ratios and sphericity to conventional water atomized powders, though with reduced flowability due to a pronounced fine fraction content. Elevated levels of oxides are observed, leading to the formation of an oxide layer on specimen blocks, without impairing the mechanical properties. Analyses of porosity, microstructure, and hardness indicate no significant differences when compared to conventional powders from water or gas atomization. This recycling approach not only mitigates waste but also enhances the potential for a circular and sustainable manufacturing process in the additive manufacturing industry and beyond.
KW - Directed Energy Deposition
KW - Recycling
KW - Stainless steel
KW - Comminution
KW - Powder characteristics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652037
DO - https://doi.org/10.1088/1757-899X/1332/1/012014
SN - 1757-8981
VL - 1332
IS - 1
SP - 1
EP - 7
PB - IOP Publishing
AN - OPUS4-65203
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
T1 - The bulging effect and its relevance in high power laser beam welding
N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high speed camera, and two thermal imaging cameras is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs above 10 mm penetration depth. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root
T2 - The 18th Nordic Laser Materials Processing Conference
CY - Lulea, Sweden
DA - 18.01.2022
KW - Laser beam welding
KW - Melt pool dinamics
PY - 2022
AN - OPUS4-54333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seitz, Georg
A1 - Bantle, Patrick
A1 - Biegler, Max
A1 - Elsner, Beatrix A. M.
A1 - Rethmeier, Michael
T1 - An Inherent Strain Method Using Progressive Element Activation for Fast Distortion Calculation in Directed Energy Deposition
N2 - The finite element analysis (FEA) simulation of directed energy deposition (DED) processes offers many potential cost savings during the build job optimization process, through, e.g., distortion predictions. However, the biggest challenge is the long calculation time, frequently exceeding the actual build time. One way of simplifying the simulation with the aim of reducing the calculation times is the inherent strain method. While this method is already used commercially in the simulation of powder bed-based processes and conventional welding technologies, its use in DED is still the subject of research. In this work, an inverse determination of an inherent strain is carried out on a 20-layer-high, single-track-wide wall, common theories are reviewed, and an approach based on thermal strain is introduced. As a result, the calculation time could be reduced by 83% and the accuracy remained at 92%.
KW - Inherent strain method
KW - Simulation
KW - Finite element analysis
KW - Directed energy deposition
KW - Additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622595
DO - https://doi.org/10.3390/met14121338
SN - 2075-4701
VL - 14
IS - 12
SP - 1
EP - 12
PB - MDPI
AN - OPUS4-62259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kampffmeyer, D.
A1 - Wolters, M.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Laserstrahlauftragschweißen – Einfluss von Schutzgasgemischen auf die Bauteilqualität
N2 - Im Additive Manufacturing Verfahren Directed Energy Deposition (DED) wird bei der Verarbeitung von Werkzeugstahl in der Regel reines Argon als Schutzgas verwendet. Dabei kann die Verwendung von speziellen Schutzgasgemischen, auch bei geringen Anteilen zugemischter Gase, durchaus die Bauteilqualität positiv beeinflussen.
In Vorarbeiten der Messer SE & Co. KGaA zeigte ein gewisser Sauerstoffanteil im Schutzgas die Tendenz, den Flankenwinkel von Schweißspuren beim DED zu verbessern. In der vorliegenden Studie wurde daher detailliert untersucht in wie weit unterschiedliche Schutzgasgemische einen Einfluss auf die Qualität sowie die geometrischen Eigenschaften der additiv gefertigten Strukturen des Werkzeugstahls 1.2709 beim Laser-DED ausüben. Es erfolgten zunächst Testschweißungen in Form von Einzelspuren mit unterschiedlichen Gemischen aus dem Basisschutzgas Argon mit geringen Anteilen verschiedener Gase. Dabei wurde der Einfluss der Zusätze auf die Spurgeometrie und Aufbauqualität untersucht. Auf Basis dieser Vorversuche wurde eine Auswahl vielversprechender Gasgemische getroffen und Detailuntersuchungen in Form von Spuren, Flächen und Quadern unter Zugabe verschiedener Mengen an Zusätzen durchgeführt. Zur Bewertung des Einflusses der Schutzgasbeimengungen wurden der Flankenwinkel, die Porosität und das Gefüge der Proben anhand metallografischer Schliffe untersucht. Es zeigte sich, dass eine Zugabe von geringen Anteilen an Zusätzen zunächst zu einer Vergrößerung des Flankenwinkels im Vergleich zu reinem Argon führt. Mit steigendem Anteil der Gase nimmt dieser Winkel jedoch ab. So kann je nach Menge des zugesetzten Gases eine individuelle Benetzung des aufgetragenen Materials an der Oberfläche erreicht werden. Auch die Porosität ließ sich durch Schutzgasgemische beeinflussen und zeigt ein abweichendes Verhalten im Vergleich zu reinem Argon.
T2 - DVS Congress 2023 Große Schweißtechnische Tagung DVS CAMPUS
CY - Essen, Germany
DA - 11.09.2023
KW - Laser-Pulver-Auftragschweißen
KW - DED-LB
KW - Schutzgas
KW - Additive Fertigung
PY - 2023
SN - 978-3-96144-230-0
SP - 505
EP - 511
PB - DVS-Media
AN - OPUS4-58585
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Ökologische Bilanzierung von Schmelzschweißverfahren unter Berücksichtigung vor- und nachgelagerter Prozessschritte
N2 - Ein wesentliches Ziel der deutschen Industriepolitik besteht darin, Rahmenbedingungen zu schaffen, welche die Positionierung nachhaltiger Produkte und Prozesse innerhalb globaler Wertschöpfungsketten ermöglichen und ökoeffiziente Fertigungsprozesse langfristig sichern. In diesem Beitrag werden aktuelle Forschungsarbeiten zur Bewertung der Umweltwirkungen der schweißtechnischen Fertigungskette anhand ausgewählter Schmelzschweißverfahren unter Berücksichtigung vor- sowie nachgelagerter Fertigungsschritte dargestellt. Eine weit verbreitete und standardisierte Methode zur Abschätzung der Umweltwirkungen eines Produkts oder Prozesses ist die Ökobilanzierung. Hierbei stellen die Sachbilanzierung, das heißt die Ermittlung sämtlicher relevanter Energie- und Ressourcenverbräuche während der schweißtechnischen Fertigung, aufgrund des hohen Dokumentationsaufwands, sowie die Ableitung assoziierter Wirkkategorien das größte Hindernis für eine Etablierung und Akzeptanz der Ökobilanzierung in der Praxis dar. Gleichwohl wird seitens Unternehmen, welche als Zulieferer von OEM’s (engl.: original equipment manufacturer) agieren, die Dokumentation des fertigungsspezifischen CO2-Verbrauches gefordert. Ein weiterer Aspekt der Arbeiten beinhaltet Methoden zur automatisierten Erfassung von schweißtechnischen Produktionsdaten sowie deren Nachverfolgbarkeit. Anhand unterschiedlicher Schweißverfahren werden die aus den Produktionsdaten abgeleiteten Energie- und Ressourcenverbräuche automatisiert in die relevanten Umweltwirkungen überführt. Die analysierten Schweißprozesse umfassen dabei ein breites für kleine und mittlere Unternehmen (KMU) relevantes Spektrum. Durch die softwareseitige Bereitstellung der aufgestellten Umweltprofile ist der Anwender in der Lage, Schweißprozesse unter ökologischen Aspekten zu bewerten und die effizienteste Variante zu identifizieren.
T2 - Webinar „Zukunft des Bauens – Nachhaltigkeit bei Errichtung, Abbruch und Rückbau“
CY - Online meeting
DA - 15.11.2021
KW - Ökobilanzierung
KW - Verfahrensvergleich
KW - Umweltwirkungen
PY - 2021
AN - OPUS4-56649
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, A.
A1 - Saeed, A.
A1 - Dawood, U.
A1 - Abdelbary, H.
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
T1 - Nano-MnO2/xanthan gum composite films for NO2 gas sensing
N2 - Nowadays, sensors based on polymers/nanostructured metal oxide composites have been investigated exten-sively because of their sensitivity to NO2 gas at ambient temperature. In this work, nanocomposite membranes of xanthan gum (XG) with different contents of MnO2 nanoparticles were prepared as a potential NO2 gas sensor operating at room temperature by a simple one-step oxidation-reduction reaction. The structural, morphological, thermal, and electrical properties of the composite membrane were investigated. The FT-IR results confirm the successful preparation of MnO2 through the oxidation of XG by KMnO4 and reveal further the structural changes of the XG/MnO2 nanocomposite upon its exposure to NO2 gas. The capping of the synthesized MnO2 nano-particles by XG, the surface composition of the XG/MnO2 nanocomposite membranes, and the effect of NO2 gas on the surface composition was investigated using the XPS technique. The DC conductivity and dielectric loss of nanocomposites were higher than for neat XG. The conductivities of the nanocomposites XG/MO-4, XG/MO-4/ low NO2, and XG/MO-4/high NO2 composites are half, one, and three orders of magnitude higher than that for pure XG revealing a transition from insulating to conductive properties. The results demonstrated that XG/MnO2 nanocomposite membranes are promising for potential applications in NO2 gas sensing.
KW - Gas sensors
KW - Membranes
KW - Metal oxides
KW - Nanocomposites
KW - Semiconductors
PY - 2022
DO - https://doi.org/10.1016/j.matchemphys.2022.127277
SN - 0254-0584
VL - 296
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-56769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Szymoniak, Paulina
A1 - Qu, Xintong
A1 - Schönhals, Andreas
A1 - Sturm, Heinz
ED - Sinapius, M.
ED - Ziegmann, G.
T1 - Characterization of Polymer Nanocomposites
N2 - The complex effect of nanoparticles on an epoxy-based and anhydride cured DGEBA/Boehmite nanocomposite with different particle concentrations is considered in this chapter. A combination of X-ray scattering, calorimetry (fast scanning and temperature modulated calorimetry) and dielectric spectroscopy was employed to characterize the structure, vitrification kinetics and the molecular dynamics of the nanocomposites. Firstly, the unfilled polymer was found to be intrinsically heterogeneous, showing regions with different crosslinking density, indicated by two separate dynamic glass transitions. Moreover, the glass transition temperature decreases with increasing nanoparticle concentration, as a result of changes in the crosslinking density. In addition, it was shown that the incorporation of nanoparticles can result in simultaneous increase in the number of mobile segments for low nanoparticle concentrations and on the other hand, for higher loading degrees the number of mobile segments decreases, due to the formation of an immobilized interphase.
KW - Rigid amorphous fraction
KW - Epoxy nanocomposites
KW - X-ray scattering
KW - Differential scanning calorimetry
KW - Broadband dielectric spectroscopy
KW - Flash DSC
PY - 2021
DO - https://doi.org/10.1007/978-3-030-68523-2_4
SP - 55
EP - 77
PB - Springer Nature
AN - OPUS4-52698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Kantenbeschichtung für das Laserstrahlschweißen dickwandiger Duplexstahl-Bleche
N2 - Duplexstähle finden in vielen industriellen Bereichen Anwendung, dies ist nicht zuletzt ihren hervorragenden Eigenschaften, wie einer guten Korrosionsbeständigkeit, einer guten Duktilität bei trotzdem hoher Festigkeit, zuzuschreiben. Diese Eigenschaften werden jedoch durch das Schweißen, vor allem das Laserstrahlschweißen, beeinträchtigt, da die hohen Abkühlraten zu erhöhten Ferritanteilen im Schweißgut führen. Mit Hilfe eines zweistufigen Prozesses, bei dem die Kanten der Fügepartner vor dem Schweißen mit nickelhaltigem Pulver beschichtet werden, soll dieses Problem für dickwandige Bleche gelöst werden.
In diesem Zusammenhang wurden verschiedene Prozessparameter für den Laser-Pulver-Auftragschweiß-Prozess untersucht sowie die defektfreie Schweißung dieser beschichteten Kanten mit unterschiedlichen Prozessgasen.
KW - Pufferschichten
KW - Laser-Pulver-Auftragschweißen
KW - Laserstrahlschweißen
KW - Duplex
PY - 2020
VL - 72
IS - 7
SP - 382
EP - 387
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-50145
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
T1 - Adaptive manufacturing strategies for DED-Arc: Case studies on high-strength aluminium alloys and gas-turbine blade repair
N2 - In this presentation, we showcase BAM’s current research activities on DED-Arc/M processes, covering both the manufacture of novel high-strength aluminium alloys and the development of automated repair strategies for gas turbine blades, with a focus on robust process control and repeatable component quality.
T2 - 12. Wissenschaftliches Kolloquium im Rahmen des SFB/TRR 375 "Multifunktionale Hochleistungskomponenten aus hybriden porösen Materialien"
CY - Online meeting
DA - 05.02.2026
KW - DED-Arc
KW - Automation
KW - Quality assessment
PY - 2026
AN - OPUS4-65472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
A1 - Fabry, Çağtay
A1 - Rethmeier, Michael
A1 - Ratkovac, Mirjana
A1 - Thiele, Marc
A1 - Baeßler, Matthias
T1 - Innovative Design- und Fertigungsstrategien zur Steigerung der Leichtbaupotenziale im Stahlbau
N2 - Offshore wind energy plays an important role for the desired transition towards a carbon dioxide free industry within the next decades. However, the grounding of the offshore wind plants governs the overall installation process besides bureaucratic bottlenecks.
The application of lightweight principles in steel construction, e.g. the usage dissolved load-bearing structures, so called Jackets foundations, offer great potential in reducing the resource consumption, especially with respect to the needed amount of steel.
In this context this presentation focuses on a fully digitalization of the welding manufacturing and as well as testing chain to enable a fully automated manufacturing as well as quality assessment of tubular nodes as key element of Jackets foundation structures. Furthermore, the relationship between the seam shape geometry and resulting fatigue strength is evaluated by numerical methods incorporating bionic principles. It is shown that tubular nodes can be welded fully automatically taking geometry tolerances into account. Moreover, the seam shape could be manufactured as requested by the numerical models which offers great potential for an extended lifetime. Subsequently, the improvements in resource efficiency and reduction of carbon dioxide emissions are evaluated by a life-cycle-assessment.
T2 - Leichtbau in der Hauptstadtregion - Rohstoffe - Recycling - Rohstoffe: Kreislaufwirtschaft im Leichtbau
CY - Berlin, Germany
DA - 28.11.2022
KW - Offshore Windenergie
KW - Gründungsstrukturen
KW - Leichtbau
KW - Automatisierte schweißtechnische Fertigung
PY - 2022
AN - OPUS4-56657
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - SmartWeld - Innovatives Design und Fertigungskonzept zur Steigerung der Leichtbaupotenziale im Stahlbau
N2 - Die Anwendung von Leichtbauprinzipien im Stahlbau, wie z.B. die Verwendung von aufgelösten Tragstrukturen, sog. Jackets-Fundamenten, bietet ein großes Potential zur Reduzierung des Ressourcenverbrauchs, insbesondere im Hinblick auf die benötigte Stahlmenge.
In diesem Vortrag zeigen wir die Potenziale einer vollständigen Digitalisierung der schweißtechnischen Fertigungs- und Prüfkette auf, um eine vollautomatische Fertigung sowie Qualitätsprüfung von Rohrknoten als Schlüsselelement von Jackets-Fundamenten zu ermöglichen. Darüber hinaus wird der Zusammenhang zwischen der Geometrie der Nahtform und der resultierenden Ermüdungsfestigkeit durch numerische Methoden unter Einbeziehung bionischer Prinzipien bewertet. Es wird gezeigt, dass Hohlprofilknoten vollautomatisch unter Berücksichtigung von Geometrietoleranzen geschweißt werden können. Darüber hinaus konnte die Nahtform gemäß den numerischen Modellen hergestellt werden, was ein großes Potenzial für eine verlängerte Lebensdauer bietet. Anschließend werden die Verbesserungen bei der Ressourceneffizienz und die Reduzierung der Kohlendioxidemissionen durch eine Lebenszyklusanalyse bewertet.
T2 - Bundesverband der Windparkbetreiber Offshore: Tagung der Arbeitsgruppe Engineering
CY - Online meeting
DA - 26.11.2021
KW - Offshore Windenergieanlagen
KW - Gründungsstrukturen
KW - Automatisierte Fertigung
KW - Aufgelöste Tragstrukturen
PY - 2021
AN - OPUS4-56652
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Ghnatios, C.
A1 - Klawoon, Alexander
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
A1 - Robens-Radermacher, Annika
T1 - Efficient bead-on-plate weld model for parameter estimation towards effective wire arc additive manufacturing simulation
N2 - Despite the advances in hardware and software techniques, standard numerical methods fail in providing real-time simulations, especially for complex processes such as additive manufacturing applications. A real-time simulation enables process control through the combination of process monitoring and automated feedback, which increases the flexibility and quality of a process. Typically, before producing a whole additive manufacturing structure, a simplified experiment in the form of a beadon-plate experiment is performed to get a first insight into the process and to set parameters suitably. In this work, a reduced order model for the transient thermal problem of the bead-on-plate weld simulation is developed, allowing an efficient model calibration and control of the process. The proposed approach applies the proper generalized decomposition (PGD) method, a popular model order reduction technique, to decrease the computational effort of each model evaluation required multiple times in parameter estimation, control, and optimization. The welding torch is modeled by a moving heat source, which leads to difficulties separating space and time, a key ingredient in PGD simulations. A novel approach for separating space and time is applied and extended to 3D problems allowing the derivation of an efficient separated representation of the temperature.
The results are verified against a standard finite element model showing excellent agreement. The reduced order model is also leveraged in a Bayesian model parameter estimation setup, speeding up calibrations and ultimately leading to an optimized real-time simulation approach for welding experiment using synthetic as well as real measurement data.
KW - Proper generalized decomposition
KW - Model order reduction
KW - Hardly separable problem
KW - Additive manufacturing
KW - Model calibration
KW - Wire arc additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596502
DO - https://doi.org/10.1007/s40194-024-01700-0
SN - 0043-2288
SP - 1
EP - 18
PB - Springer
AN - OPUS4-59650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX Projektvorstellung
N2 - Der Vortrag gibt eine Übersicht über die fortlaufende Entwicklung des WelDX Projektes an der BAM.
Die Notwendigkeit des Datenaustausches für die deutsche Forschungslandschaft im Bereich des Lichtbogenschweißens wird motiviert und die wesentlichen Funktionen der weldx Python-Bibliothek anhand von Forschungsbeispielen dargestellt.
T2 - Sitzung des DVS Fachausschuss FA03 - Lichtbogenschweißen
CY - Ilmenau, Germany
DA - 13.05.2025
KW - Forschungsdatenmanagement
KW - Lichtbogenschweißen
KW - Digitalisierung
KW - Weldx
PY - 2025
AN - OPUS4-63278
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - Welding Process Data Management - Perspectives on the BAM Data Store
N2 - Arc welding processes are an important manufacturing technology applied to a wide range of critical materials and components such as offshore constructions, pressure vessels and additive manufacturing. Data management for experimental arc welding research faces the challenge of constantly changing experimental setups, incorporating a wide range of custom sensor integrations. Measurements include timeseries process and temperature recordings, 3D-geometry data and video recordings of the process from a sub-millisecond scale to multiple hour-long experiments. In addition, various manual pre-processing steps of the workpieces need to be considered to track the complete manufacturing process and its analysis – from raw materials to final dataset and publication.
As a unified RDM system, the BAM Data Store offers the capability to incorporate all steps – albeit not without its own challenges.
The talk gives an overview of the different workflows and processing steps along the welding experiments together with their integration into the BAM Data Store. Current solutions and ongoing integration work is explained and discussed. This includes the direct integration and upload of automated processing steps into the Data Store from different machines and sensors using custom Python APIs.
Ultimately the complete processing chain across multiple internal steps should be represented in the Data Store.
T2 - Data Store Days
CY - Berlin, Germany
DA - 09.03.2025
KW - Data Store
KW - Openbis
KW - Research Data Management
KW - Reference Data
KW - Welding
PY - 2025
AN - OPUS4-62976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Churiaque Bermejo, C.
A1 - Sánchez-Amaya, J. M.
A1 - Porrúa-Lara, M.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - The Effects of HLAW Parameters for One Side T-Joints in 15 mm Thickness Naval Steel
N2 - The present contribution is the first research reporting full penetration HLAW joints in 15 mm thick EH36 steel butt T-welds with square grooves on 2F welding position by single-sided welding. The effects of welding parameters were investigated to increase the quality of the joints.
Conditions leading to defect-free full penetration welds fulfilling naval regulations includes a laser power of 12.5 kW, a welding speed of 1.6 m/min and the vertical laser offset distance from the flange of 1 mm. Advanced characterization of selected welds included a microstructural identification by optical microscopy, SEM, and XRD, revealing the presence of acicular, polygonal and Widmanstätten ferrite, lath martensite, and some retained austenite at FZ. Hardness and microhardness mapping tests showed values of 155 HV at base metal and 200 to 380 HV at the fusion zone connecting the web to the flange.
KW - Ship building
KW - Laser beam welding
KW - Hybrid laser arc welding
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523931
DO - https://doi.org/10.3390/met11040600
VL - 11
IS - 4
SP - 600
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altenburg, Simon
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Maierhofer, Christiane
T1 - In-situ monitoring of a laser metal deposition (LMD) process: comparison of MWIR, SWIR and high-speed NIR thermography
N2 - Additive manufacturing offers a range of novel applications. However, the manufacturing process is complex and the production of almost defect-free parts with high reliability and durability is still a challenge. Thermography is a valuable tool for process surveillance, especially in metal additive manufacturing processes. The high process temperatures allow one to use cameras usually operating in the visible spectral range. Here, we compare the results of measurements during the manufacturing process of a commercial laser metal deposition setup using a mid wavelength infrared camera with those from a short wavelength infrared camera and those from a visual spectrum high-speed camera with band pass filter in the near infrared range.
KW - Additive Manufacturing
KW - Process monitoring
KW - Thermography
KW - LMD
KW - Metal
KW - MWIR
KW - SWIR
KW - NIR
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516318
DO - https://doi.org/10.1080/17686733.2020.1829889
VL - 19
IS - 2
SP - 97
EP - 114
PB - Taylor & Francis Group
CY - London, UK
AN - OPUS4-51631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Karkhin, V.
A1 - Rethmeier, Michael
T1 - On the relationship between the bulge effect and the hot cracking formation during deep penetration laser beam welding
N2 - Recent studies have confirmed the widening of the weld pool interface, known as a bulge effect, during deep penetration high power laser beam welding. The link between such geometric particularities of the weld pool shape and the hot cracking phenomena is significant. The present work seeks to extend the level of understanding by investigating their relationship. A coupled multiphysics, multiscale numerical framework is developed, comprising a series of subsequent analyses. The study examines the influences of the bulge on the three most dominant effects causing hot cracking, namely the thermal cycles, the mechanical loading, and the local microstructure. The bulge in the weld pool shape forms approximately in the middle of the plate, thus correlating with the location of hot cracking. It increases the hot cracking susceptibility by enhancing the three dominant effects. The numerical results are backed up by experimental data.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
KW - Hot cracking
KW - Bulge effect
KW - Numerical modelling
KW - Laser beam welding
KW - Deep penetration
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512783
DO - https://doi.org/10.1016/j.procir.2020.09.002
SN - 2212-8271
VL - 94
SP - 5
EP - 10
PB - Elsevier B.V.
CY - Amsterdam [u.a.]
AN - OPUS4-51278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Uhlmann, E.
A1 - Düchting, J.
A1 - Petrat, T.
A1 - Krohmer, E.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Effects on the distortion of Inconel 718 components along a hybrid laser‑based additive manufacturing process chain using laser powder bed fusion and laser metal deposition
N2 - The combination of laser powder bed fusion (LPBF), known for its geometrical freedom and accuracy, and the nozzle-based laser metal deposition process (LMD), known for its high build-up rates, has great potential to reduce the additive manufacturing times for large metallic parts. For the industrial application of the LPBF-LMD hybrid process chain, it is necessary to investigate the infuence of the LMD process on the LPBF substrate. In addition, the build plate material also has a signifcant impact on the occurrence of distortion along the additive manufacturing process chain. In the literature, steel build plates are often used in laser-based additive manufacturing processes of Inconel 718, since a good metallurgical Bonding can be assured whilst reducing costs in the production and restoration of the build plates. This paper examines the distortion caused by LMD material deposition and the infuence of the build plate material along the hybrid additive manufacturing process chain. Twin cantilevers are manufactured by LPBF and an additional layer is subsequently deposited with LMD. The distortion is measured in the as-built condition as well as after heat treatment. The efect of diferent LMD hatch strategies on the distortion is determined. The experiments are conducted using the nickel-base alloy Inconel 718. The results show a signifcant infuence of LMD path strategies on distortion, with shorter tool paths leading to less distortion. The remaining distortion after heat treatment is considerably dependent on the material of the build plate.
KW - Laser powder bed fusion
KW - Directed energy deposition
KW - Laser metal deposition
KW - Distortion
KW - Heat treatment
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521439
DO - https://doi.org/10.1007/s40964-021-00171-9
SP - 1
EP - 10
PB - Springer-Verlag GmbH
CY - Heidelberg
AN - OPUS4-52143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Hybrid laser-arc welding of thick-walled pipe segments with optimization of the end crater
N2 - The study deals with the application of the high-power hybrid-laser arc welding process on up to 15 mm thick pipe segments with the intention to avoid end crater imperfections during closing of the circumferential welds, where the pipes were turned during welding in 1G- and 2Gpositions.
Different techniques such as laser power ramp-down, abrupt switch-off of the laser power and change of the magnification of the laser spot diameter and defocusing of the laser beam relative to the workpiece were tested to remove the laser energy from the process. It could be shown that a high defocusing of the optic system above 40 mm with a resulting beam diameter > 2.9 mm in a short overlap length of approx.
20 mm leads to the formation of a cup-shaped weld seam, which is preferred for avoidance of cracks and pores in the end crater. A laser optics with motor-driven lens system was used for the welding experiments to defocuse the laser beam without changing the position of the arc.
KW - Hybrid laser-arc welding
KW - Circumferential weld
KW - Thick-walled steel
KW - Single-pass welding
KW - End crater
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513260
DO - https://doi.org/10.1016/j.procir.2020.09.106
VL - 94
SP - 676
EP - 679
PB - Elsevier B.V.
AN - OPUS4-51326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical study of additional element transport in wire feed laser beam welding
N2 - The transport phenomena in the wire feed laser beam welding are investigated numerically. A three-dimensional transient heat transfer and fluid flow model coupled with free surface tracing and element transport is developed. A ray-tracing method with local grid refinement algorithm is used to calculate the multiple reflections and Fresnel absorption on the keyhole wall. The filler material flows backward along the lateral side of the weld pool, and subsequently flows forward along the longitudinal plane. The occurrence of the bulging phenomenon may further prevent the downward transfer of the additional elements to the root of the weld pool.
KW - Laser beam welding
KW - Element transport
KW - Filler wire
KW - Numerical modelling
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513271
DO - https://doi.org/10.1016/j.procir.2020.09.129
VL - 94
SP - 722
EP - 725
PB - Elsevier B.V.
AN - OPUS4-51327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, Raphael
T1 - Influence of laser power on the melt pool shape of handheld laser beam welding of 1.5 mm thick micro alloyed steel
N2 - Manual welding of structures requires highly skilled welders due to the large heat-affected zone of arc-based processes, that can negatively impact microstructure and cause distortion. Handheld laser beam welding is a promising alternative with high welding velocity and a concentrated heat input. However, its current use in industry is limited to parts with aesthetic requirements, often made of high-alloyed steel. To extend the use of handheld laser beam welding to low-cost steels with good mechanical properties, this study investigates the influence of laser power on the melt pool shape for micro-alloyed steel with a thickness of 1.5 mm. Tested joint geometries are T-joints welded with filler wire as well as butt joints and overlap joints without filler wire, which are typically found in assemblies under mechanical load. Weld quality is assessed by weld porosity analysis. The results show that the handheld laser beam welding with filler wire produces T-joints with a very good external appearance, but with porosity between level C and D in the cross sections according to DIN EN ISO 13919-1. By increasing the laser power, a deep penetration of the T-joint zone can be achieved without increasing the actual throat thickness. For handheld laser beam welding of butt joints a full penetration weld of the highest quality class can be reached. Overlap joints can be welded with full or partial penetration depending on the laser power selected, with quality classes between B and C in terms of porosity.
T2 - 20th Nordic Laser Materials Processing Conference
CY - Kongens Lyngby, Denmark
DA - 26.08.2025
KW - Hand held laser welding
KW - Laser beam welding
KW - Low alloyed steel
KW - Process parameter
PY - 2025
AN - OPUS4-64169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, R.
A1 - Seifert, M.
A1 - George, Janine
A1 - Blaurock, S.
A1 - Botti, S.
A1 - Krautscheid, H.
A1 - Grundmann, M.
A1 - Sturm, C.
T1 - Determination of acoustic phonon anharmonicities via second-order Raman scattering in CuI
N2 - We demonstrate the determination of anharmonic acoustic phonon properties via second-order Raman scattering exemplarily on copper iodide single crystals. The origin of multi-phonon features from the second-order Raman spectra was assigned by the support of the calculated 2-phonon density of states. In this way, the temperature dependence of acoustic phonons was determined down to 10 K. To determine independently the harmonic contributions of respective acoustic phonons, density functional theory in quasi-harmonic approximation was used. Finally, the anharmonic contributions were determined. The results are in agreement with earlier publications and extend CuI’s determined acoustic phonon properties to lower temperatures with higher accuracy. This approach demonstrates that it is possible to characterize the acoustic anharmonicities via Raman scattering down to zero-temperature renormalization constants of at least 0.1 cm⁻¹.
KW - Thermoelectrics
KW - Thermal transport
KW - Phonon interactions
KW - Density functional theory
KW - Phonons
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593164
DO - https://doi.org/10.1088/1367-2630/ad1141
SN - 1367-2630
VL - 25
IS - 12
SP - 1
EP - 12
PB - IOP Publishing
CY - London
AN - OPUS4-59316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prabitz, Konstantin Manuel
A1 - Antretter, Thomas
A1 - Rethmeier, Michael
A1 - El-Sari, Bassel
A1 - Schubert, Holger
A1 - Hilpert, Benjamin
A1 - Gruber, Martin
A1 - Sierlinger, Robert
A1 - Ecker, Werner
T1 - Numerical and experimental assessment of liquid metal embrittlement in externally loaded spot welds
N2 - Zinc-based surface coatings are widely applied with high-strength steels in automotive industry. Some of these base materials show an increased brittle cracking risk during loading. It is necessary to examine electrogalvanized and uncoated samples of a high strength steel susceptible to liquid metal embrittlement during spot welding with applied external load. Therefore, a newly developed tensile test method with a simultaneously applied spot weld is conducted. A fully coupled 3D electrical, thermal, metallurgical and mechanical finite element model depicting the resistant spot welding process combined with the tensile test conducted is mandatory to correct geometric influences of the sample geometry and provides insights into the sample’s time dependent local loading. With increasing external loads, the morphology of the brittle cracks formed is affected more than the crack depth. The validated finite element model applies newly developed damage indicators to predict and explain the liquid metal embrittlement cracking onset and development as well as even ductile failure.
KW - Resistance spot welding
KW - Finite element simulation
KW - Advanced high-strength steel
KW - Liquid metal embrittlement
KW - Damage prediction
KW - Tensile resistance spot welding experiment
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594848
DO - https://doi.org/10.1007/s40194-024-01696-7
SN - 0043-2288
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-59484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Rethmeier, Michael
T1 - Challenges in dynamic heat source modeling in high-power laser beam welding
N2 - The amount of absorbed energy in the keyhole as well as its spatial and temporal distribution is essential to model the laser beam welding process. The recoil pressure, which develops because of the evaporation process induced by the absorbed laser energy at the keyhole wall, is a key determining factor for the macroscopic flow of the molten metal in the weld pool during high-power laser beam welding. Consequently, a realistic implementation of the effect of laser radiation on the weld metal is crucial to obtain reliable and accurate simulation results. In this paper, we discuss manyfold different improvements on the laser-material interaction, namely, the ray tracing method, in the numerical simulation of the laser beam welding process. The first improvement relates to locating the exact reflection points in the ray tracing method using a so-called cosine condition in the determination algorithm for the intersection of reflected rays and the keyhole surface. A second correction refers to the numerical treatment of the Gaussian distribution of the laser beam, whose beam width is defined by a decay of the laser intensity by a factor of 1/e2, thus ignoring around 14% of the total laser beam energy. In the third step, the changes in the laser radiation distribution in the vertical direction were adapted by using different approximations for the converging and the diverging regions of the laser beam, thus mimicking the beam caustic. Finally, a virtual mesh refinement was adopted in the ray tracing routine. The obtained numerical results were validated with experimental measurements.
KW - Laser beam welding
KW - Laser energy distribution
KW - Ray tracing
KW - Numerical modeling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584748
DO - https://doi.org/10.2351/7.0001079
VL - 35
IS - 4
SP - 1
EP - 9
PB - Laser Institute of America
AN - OPUS4-58474
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naik, Aakash
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - Jackson, Adam J.
A1 - George, Janine
T1 - LobsterPy: A package to automatically analyze LOBSTERruns
N2 - The LOBSTER (Deringer et al., 2011;Maintz et al., 2013 ,2016 ;Nelson et al., 2020 ) software aids in extracting quantum-chemical bonding information from materials by projecting the plane-wave based wave functions from density functional theory (DFT) onto an atomic orbital basis. LobsterEnv, a module implemented in pymatgen (Ong et al., 2013) by some of the authors of this package, facilitates the use of quantum-chemical bonding information obtained from LOBSTER calculations to identify neighbors and coordination environments. LobsterPy is a Python package that offers a set of convenient tools to further analyze and summarize the LobsterEnv outputs in the form of JSONs that are easy to interpret and process. These tools enable the estimation of (anti) bonding contributions, generation of textual descriptions, and visualization of LOBSTER computation results. Since its first release, both LobsterPy and LobsterEnv capabilities have been extended significantly. Unlike earlier versions, which could only automatically analyze Crystal Orbital Hamilton Populations (COHPs) (Dronskowski & Blöchl, 1993), both can now also analyze Crystal Orbital Overlap Populations (COOP) (Hughbanks & Hoffmann, 1983) and Crystal Orbital Bond Index (COBI) (Müller et al., 2021). Extracting the information about the most important orbitals contributing to the bonds is optional, and users can enable it as needed. Additionally, bonding-based features for machinelearning (ML) studies can be engineered via the sub-packages “featurize” and “structuregraphs”. Alongside its Python interface, it also provides an easy-to-use command line interface (CLI) that runs automatic analysis of the computations and generates a summary of results and publication-ready figures. LobsterPy has been used to produce the results in Ngo et al. (2023), Chen et al. (2024), Naik et al. (2023), and it is also part of Atomate2 (2023) bonding analysis workflow for generating bonding analysis data in a format compatible with the Materials Project (Jain et al., 2013) API.
KW - Materials Science
KW - Automation
KW - Bonding Analysis
KW - Materials Properties
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595809
DO - https://doi.org/10.21105/joss.06286
VL - 9
IS - 94
SP - 1
EP - 4
PB - The Open Journal
AN - OPUS4-59580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosen, Andrew S.
A1 - Gallant, Max
A1 - George, Janine
A1 - Riebesell, Janosh
A1 - Sahasrabuddhe, Hrushikesh
A1 - Shen, Jimmy-Xuan
A1 - Wen, Mingjian
A1 - Evans, Matthew L.
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Rignanese, Gian-Marco
A1 - Persson, Kristin A.
A1 - Jain, Anubhav
A1 - Ganose, Alex M.
T1 - Jobflow: Computational Workflows Made Simple
N2 - We present Jobflow, a domain-agnostic Python package for writing computational workflows tailored for high-throughput computing applications. With its simple decorator-based approach, functions and class methods can be transformed into compute jobs that can be stitched together into complex workflows. Jobflow fully supports dynamic workflows where the full acyclic graph of compute jobs is not known until runtime, such as compute jobs that launch
other jobs based on the results of previous steps in the workflow. The results of all Jobflow compute jobs can be easily stored in a variety of filesystem- and cloud-based databases without the data storage process being part of the underlying workflow logic itself. Jobflow has been intentionally designed to be fully independent of the choice of workflow manager used to dispatch the calculations on remote computing resources. At the time of writing, Jobflow
workflows can be executed either locally or across distributed compute environments via an adapter to the FireWorks package, and Jobflow fully supports the integration of additional workflow execution adapters in the future.
KW - Automation
KW - Workflow
KW - Computational Materials Science
KW - Computations
KW - Software
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593104
DO - https://doi.org/10.21105/joss.05995
VL - 9
IS - 93
SP - 1
EP - 7
PB - The Open Journal
AN - OPUS4-59310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Fasselt, Janek Maria
A1 - Kruse, Tobias
A1 - Klötzer, Christian
A1 - Kleba-Ehrhardt, Rafael
A1 - Choma, Tomasz
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Using ultrasonic atomization to recycle aluminium bronze chips for additive laser directed energy deposition
N2 - Abstract
In the post-processing of large maritime components, a considerable amount of waste in the form of milling and grinding chips is produced. At the same time, additive manufacturing technologies have shown great potential in producing high-volume parts for maritime applications, allowing novel design approaches and short lead times. In this context, this study presents a sustainable approach to recycle and use aluminium bronze waste material, generated during post-processing of large cast ship propellers, as feedstock for laser-powder directed energy deposition. The recycling technology used to produce powder batches is inductive re-melting in combination with ultrasonic atomization. The derived metal powders are characterized using digital image analysis, powder flowability tests, scanning electron microscopy as well as energy dispersive X-ray spectroscopy. Compared to conventional metal powders produced by gas atomization, the recycled material shows excellent sphericity and a powder size distribution with a higher content of finer and coarser particles. Metallographic sections of deposited additively produced specimens show an increased hardness and reduced ductility, but also competitive densities and higher yield and ultimate tensile strength compared to cast material. The process chain shows high potential for the maritime sector to enable circular and sustainable manufacturing.
KW - Industrial and Manufacturing Engineering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594444
DO - https://doi.org/10.1088/1757-899X/1296/1/012036
VL - 1296
IS - 1
SP - 1
EP - 11
PB - IOP Publishing
AN - OPUS4-59444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, K.
A1 - Meschut, G.
A1 - Seitz, G.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - The Identification of a New Liquid Metal Embrittlement (LME) Type in Resistance Spot Welding of Advanced High Strength Steels on Reduced Flange Widths
N2 - Liquid metal embrittlement (LME) cracking is a phenomenon observed during resistance spot welding (RSW) of zinccoated advanced highstrength steels (AHSS) in automotive manufacturing. In this study, severe cracks are observed at the edge of the sheet under reduced flange widths. These cracks, traversing the AHSS sheet, culminate at the edge with a width of approximately 1.2 mm.
Through combined numerical and experimental investigations, and material testing, these cracks are identified and validated as a new type of LME crack. The mechanism behind this crack formation is attributed to unique geometric conditions that, when compared to center welding, amplify radial material flow by ninefold to 0.87 mm. The resultant tangential tensile stresses approximate 760 MPa, which exceed the yield strength of the examined advanced highstrength steel (AHSS) under heightened temperature conditions, and when combined with liquid zinc, promote the formation of this new type of LME crack.
KW - Liquid metal embrittlement
KW - Crack
KW - Advanced high strength steels
KW - Resistance spot welding
KW - Simulation
KW - Flange width
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586940
DO - https://doi.org/10.3390/met13101754
VL - 13
IS - 10
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-58694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Artinov, Antoni
T1 - On the mathematical analysis of the relationship between the bulging region and the centerline solidification cracking in laser beam welding
N2 - The present Ph.D. thesis provides a comprehensive experimental and theoretical study of the bulging-cracking relationship in laser beam welding of thick unalloyed steel sheets. It focuses on experimentally proving the existence of the bulging region and on developing a coupled multiphysics mathematical framework to analyze its influence on the three critical factors controlling the susceptibility to solidification cracking, namely the thermal, metallurgical, and mechanical factors.
The research employs a novel experimental setup, utilizing a combination of transparent quartz glass and thick unalloyed steel sheet, enabling real-time visualization of the weld pool geometry and confirming the existence of a distinctive bulging region. To deepen the understanding of these experimental insights, an extensive multiphysics mathematical framework was developed and rigorously verified and validated. This framework introduces an innovative approach using Lamé curves for accurately describing complex three-dimensional weld pool geometries, including the bulging region's characteristics. Through analytical solutions and numerical procedures, it facilitates the computation of solidification parameters, which are crucial for understanding the metallurgical aspects of crack formation. The framework also incorporates a mechanical model to assess and evaluate the local stress distribution within the bulging region.
The findings indicate that an elongated, sharply shaped bulging region significantly increases the susceptibility to solidification cracking. This is attributed to its adverse impact on the distribution and local dwell time of liquid metal residing at grain boundaries during solidification, combined with the localized tensile stresses identified in the bulging region.
In essence, this research contributes to the broader understanding of solidification cracking in laser beam welding of thick unalloyed steel sheets, with a particular focus on the bulging region. The insights and methodologies developed in this thesis are valuable for future research and advancements in the application of the laser beam welding technology for joining high-thickness unalloyed steel components.
KW - Bulging effect
KW - Centerline solidification cracking
KW - Mathematical modeling
KW - Structural steel
KW - High power laser beam welding
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599010
DO - https://doi.org/10.14279/depositonce-20090
SP - 1
EP - 152
CY - Berlin
AN - OPUS4-59901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Batatia, Ilyes
A1 - Benner, Philipp
A1 - Chiang, Yuan
A1 - Elena, Alin M.
A1 - Kovács, Dávid P.
A1 - Riebesell, Janosh
A1 - Advincula, Xavier R.
A1 - Asta, Mark
A1 - Avaylon, Matthew
A1 - Baldwin, William J.
A1 - Berger, Fabian
A1 - Bernstein, Noam
A1 - Bhowmik, Arghya
A1 - Bigi, Filippo
A1 - Blau, Samuel M.
A1 - Cărare, Vlad
A1 - Ceriotti, Michele
A1 - Chong, Sanggyu
A1 - Darby, James P.
A1 - De, Sandip
A1 - Della Pia, Flaviano
A1 - Deringer, Volker L.
A1 - Elijošius, Rokas
A1 - El-Machachi, Zakariya
A1 - Fako, Edvin
A1 - Falcioni, Fabio
A1 - Ferrari, Andrea C.
A1 - Gardner, John L. A.
A1 - Gawkowski, Mikołaj J.
A1 - Genreith-Schriever, Annalena
A1 - George, Janine
A1 - Goodall, Rhys E. A.
A1 - Grandel, Jonas
A1 - Grey, Clare P.
A1 - Grigorev, Petr
A1 - Han, Shuang
A1 - Handley, Will
A1 - Heenen, Hendrik H.
A1 - Hermansson, Kersti
A1 - Ho, Cheuk Hin
A1 - Hofmann, Stephan
A1 - Holm, Christian
A1 - Jaafar, Jad
A1 - Jakob, Konstantin S.
A1 - Jung, Hyunwook
A1 - Kapil, Venkat
A1 - Kaplan, Aaron D.
A1 - Karimitari, Nima
A1 - Naik, Aakash A.
A1 - Csányi, Gábor
T1 - A foundation model for atomistic materials chemistry
N2 - Atomistic simulations of matter, especially those that leverage first-principles (ab initio) electronic structure theory, provide a microscopic view of the world, underpinning much of our understanding of chemistry and materials science. Over the last decade or so, machine-learned force fields have transformed atomistic modeling by enabling simulations of ab initio quality over unprecedented time and length scales. However, early machine-learning (ML) force fields have largely been limited by (i) the substantial computational and human effort required to develop and validate potentials for each particular system of interest and (ii) a general lack of transferability from one chemical system to the next. Here, we show that it is possible to create a general-purpose atomistic ML model, trained on a public dataset of moderate size, that is capable of running stable molecular dynamics for a wide range of molecules and materials. We demonstrate the power of the MACE-MP-0 model—and its qualitative and at times quantitative accuracy—on a diverse set of problems in the physical sciences, including properties of solids, liquids, gases, chemical reactions, interfaces, and even the dynamics of a small protein. The model can be applied out of the box as a starting or “foundation” model for any atomistic system of interest and, when desired, can be fine-tuned on just a handful of application-specific data points to reach ab initio accuracy. Establishing that a stable force-field model can cover almost all materials changes atomistic modeling in a fundamental way: experienced users obtain reliable results much faster, and beginners face a lower barrier to entry. Foundation models thus represent a step toward democratizing the revolution in atomic-scale modeling that has been brought about by ML force fields.
KW - Materials Design
KW - Thermal Conducitivity
KW - Nanoparticles
KW - Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647829
DO - https://doi.org/10.1063/5.0297006
SN - 0021-9606
VL - 163
IS - 18
SP - 1
EP - 89
PB - AIP Publishing
AN - OPUS4-64782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janssen, Jan
A1 - George, Janine
A1 - Geiger, Julian
A1 - Bercx, Marnik
A1 - Wang, Xing
A1 - Ertural, Christina
A1 - Schaarschmidt, Jörg
A1 - Ganose, Alexander Miguel
A1 - Pizzi, Giovanni
A1 - Hickel, Tilmann
A1 - Neugebauer, Jörg
T1 - A Python workflow definition for computational materials design
N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron.
KW - Worklows
KW - FAIR Workflows
KW - Automation
KW - Materials Acceleration Platforms
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643325
DO - https://doi.org/10.1039/D5DD00231A
SN - 2635-098X
SP - 1
EP - 14
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yuanbin
A1 - Morrow, Joe D.
A1 - Ertural, Christina
A1 - Fragapane, Natascia L.
A1 - Gardner, John L. A.
A1 - Naik, Aakash A.
A1 - Zhou, Yuxing
A1 - George, Janine
A1 - Deringer, Volker L.
T1 - An automated framework for exploring and learning potential-energy surfaces
N2 - Machine learning has become ubiquitous in materials modelling and now routinely enables large-scale atomistic simulations with quantum-mechanical accuracy. However, developing machine-learned interatomic potentials requires high-quality training data, and the manual generation and curation of such data can be a major bottleneck. Here, we introduce an automated framework for the exploration and fitting of potential-energy surfaces, implemented in an openly available software package that we call (‘automatic potential-landscape explorer’). We discuss design choices, particularly the interoperability with existing software architectures, and the ability for the end user to easily use the computational workflows provided. We show wide-ranging capability demonstrations: for the titanium–oxygen system, SiO2, crystalline and liquid water, as well as phase-change memory materials. More generally, our study illustrates how automation can speed up atomistic machine learning in computational materials science.
KW - Automation
KW - Machine Learning
KW - Machine learning potentials
KW - Amorphous materials
KW - High-throughput
KW - Ab initio
KW - Materials property prediction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639882
DO - https://doi.org/10.1038/s41467-025-62510-6
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-63988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cope, Elana J.
A1 - Bustamante, Joana
A1 - Johnson, Zöe M.
A1 - Lancaster, Alicia
A1 - Gurunathan, Ramya
A1 - George, Janine
A1 - Agne, Matthias T.
T1 - Heat capacity estimation of complex materials for energy technologies
N2 - The control of heat in energy materials is one of the greatest current engineering challenges. Accurate estimations of heat capacity are key in creating and using materials safely and efficiently. Current models for heat capacity are often limited due to crude estimations of the phonon density of states, which is a key component of the thermodynamic definition of heat capacity. Utilization of a more detailed phonon density of states, which can easily be obtained from machine-learned algorithms, combined with dilation and electronic contributions, yields heat capacity estimations that are 29% better than the widely utilized Debye model and are comparable to state-of-the-art quantum mechanical calculations. The framework and necessary tools for heat capacity estimations demonstrated herein can be built into more detailed models and analyses, such as high-throughput characterization, transport models, or other thermodynamic assessments. Consequently, the so-called vibrational + dilation + electronic (VDE) model of heat capacity developed in this work better enables the informed design of next-generation devices.
KW - Materials Design
KW - Heat Capacity
KW - Machine learning potentials
KW - Thermal Management
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645711
DO - https://doi.org/10.1016/j.joule.2025.102054
SN - 2542-4351
VL - 9
IS - 8
SP - 1
EP - 12
PB - Elsevier Inc.
AN - OPUS4-64571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Liu, Yuanbin
A1 - Zhou, Yuxing
A1 - Ademuwagun, Richard
A1 - Walterbos, Luc
A1 - George, Janine
A1 - Elliott, Stephen R.
A1 - Deringer, Volker L.
T1 - Medium-range structural order in amorphous arsenic
N2 - Medium-range order (MRO) is a key structural feature of amorphous materials, but ist origin and nature remain elusive. Here, we reveal the MRO in amorphous arsenic (a-As) using advanced atomistic simulations, based on machine-learned potentials derived using automated workflows. Our simulations accurately reproduce the experimental structurefactor of a-As, especially the first sharp diffraction peak (FSDP), which is a signature of MRO. We compare and contrast the structure of a-As with that of its lighter homologue, red amorphous phosphorus (a-P), identifying the dihedral-angle distribution as a key factor differentiating the MRO in both. The pressure-dependent structural behaviors of a-As and a-P differ as well, which we link to the interplay of ring topology and structural entropy. We finally show that the origin of the FSDP is closely correlated with the size and spatial distribution of voids in the amorphous networks. Our work provides fundamental insights into MRO in an amorphous elemental system, and more widely it illustrates the usefulness of automation for machine-learning-driven atomistic simulations.
KW - Materials Design
KW - Amorphous
KW - Machine Learning
KW - Machine Learning Interatomic Potentials
KW - Automation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640204
DO - https://doi.org/10.48550/arXiv.2509.02484
SP - 1
EP - 43
AN - OPUS4-64020
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoque, Maroof Arshadul
A1 - Sommerfeld, Thomas
A1 - Lisec, Jan
A1 - Das, Prasenjit
A1 - Prinz, Carsten
A1 - Heinekamp, Christian
A1 - Stolar, Tomislav
A1 - Etter, Martin
A1 - Rosenberger, David
A1 - George, Janine
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Mechanochemically Synthesized Covalent Organic Framework Effectively Captures PFAS Contaminants
N2 - Per‐ and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that pose significant health risks, prompting urgent efforts to develop effective removal methods and adsorbers. Covalent organic frameworks (COFs) are metal‐free adsorbers with high stability and tunable porosity. A highly crystalline COF is synthesised mechanochemically using 1,3,5‐tris(4‐aminophenyl)benzene (TAPB) and 1,3,5‐triformylbenzene (TFB). The formation dynamics are monitored in real time with time‐resolved in situ synchrotron X‐ray diffraction. The TAPB‐TFB COF demonstrates good efficiency in eliminating PFAS from water. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are effectively extracted, and most of the adsorption occurred within the first 10 min. Additionally, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and DFT calculations are employed to elucidate the molecular interactions between PFAS and the COF framework. The rapid and efficient removal of PFAS makes TAPB‐TFB COF a promising material for water treatment applications.
KW - COFs
KW - Ball-milling
KW - PFAS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648712
DO - https://doi.org/10.1002/smll.202509275
SN - 1613-6810
VL - 21
IS - 44
SP - 1
EP - 8
PB - Wiley
CY - Weinheim
AN - OPUS4-64871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yalçınyüz, Aybike
A1 - Raute, Julius
A1 - Gonzalez-Gutierrez, Joamin
A1 - Pei, Eujin
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Electron Beam Bonding: A novel method for joining additively manufactured carbon fiber thermoplastic composites with aluminum to produce multi-material joints for lightweight applications
N2 - In recent years, new solutions have been explored to reduce the weight of components for the automotive, railway, and aerospace industries. For this reason, Carbon Fiber Composites (CFCs) have increasingly replaced metals in products that need to be lightweight. However, due to their poor thermal conductivity, CFCs have limited use in applications requiring efficient heat dissipation. In such applications, conventionally manufactured metal alloys are typically utilized. To address these limitations, a novel approach using a combination of additively manufactured aluminum and CFCs is proposed to exploit the distinct advantages of both materials. These innovative hybrid structures aim to combine good structural and thermal management properties with reduced weight compared to conventionally produced metal products. In this study, additively manufactured aluminum alloy (AlSi10Mg) and short carbon fiber Polyamide 6 composite (sCF-PA6) are utilized to produce metal–polymer pairs using electron beam energy to bond the two materials. Direct irradiation of short CFCs with electron beam leads to polymer degradation. Thus, a novel method “Electron Beam Bonding” for joining CFCs with aluminum alloy in various joint configurations using electron beam technology is demonstrated. This innovative approach presents a promising solution for creating metal–polymer multi-materials for lightweight applications.
KW - Electron beam bonding
KW - Multi-material
KW - Lightweight
KW - Additive manufactured materials
KW - Short carbon fiber composites
KW - AlSi10Mg
KW - Joining
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641705
DO - https://doi.org/10.1007/s40964-025-01206-1
SN - 2363-9512
SP - 1
EP - 7
PB - Springer International Publishing
CY - Cham
AN - OPUS4-64170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Klotz, Ulrich E.
A1 - Tiberto, Dario
A1 - Vafaeenezhad, Hossein
A1 - Mishurova, Tatiana
A1 - Skrotzki, Birgit
T1 - Effect of keyhole and lack-of-fusion pores on the anisotropic microstructure and mechanical properties of PBF-LB/M-produced CuCrZr alloy
N2 - Due to the high reflectance and heat conductivity of copper and its alloys, the processing window for laser-based powder bed fusion (PBF-LB/M) processing of high-density copper components fundamentally overlaps with conduction and keyhole melting zones, resulting in the emergence of certain pores in the structure of printed parts. The present research aims to study how the development of process-induced lack-of-fusion or keyhole porosities during the PBF-LB/M process can affect the anisotropic microstructure and mechanical properties of the produced copper alloys. For this purpose, several samples were produced utilizing a similar CuCrZr-feedstock composition but varied process parameters from different areas of the PBF-LB/M processing window, specifically at laser powers of 300 W and 380 W which define the boarders of the conduction and keyhole regimes. X-ray computed tomography (XCT) revealed that the 300-W and 380-W samples achieved relative densities of 98.88% and 99.99%, respectively, with elongated lack-of-fusion pores forming at 300 W and semi-spherical keyhole pores at 380 W. Microstructural analyses employing scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) demonstrated strong anisotropy in different build directions of the samples, owing to the growth of long columnar grains with intense < 101 orientation along the build directions. Here, the emergence of different types of pores can cause competition between the epitaxial growth of columnar grains and the heterogeneous nucleation of new grains on the layers’ interfaces, thereby significantly varying the grain size, preferred orientation, crystallographic texture, and microstructural anisotropy of the samples. Furthermore, compression tests and nanoindentation measurements of the printed alloys in the longitudinal and transverse directions revealed that the 300 W and 380 W samples exhibited compressive strength anisotropies of 0.061 and 0.072, and average nanoindentation hardness values of 1.3 GPa and 1.5 GPa, respectively. The orientation of elongated lack-of-fusion porosities perpendicular to the loading axis was identified as the most damaging factor, significantly reducing mechanical performance compared to the uniformly distributed keyhole pores.
KW - Copper Alloy
KW - Laser-based powder bed fusion
KW - Microstructure
KW - Mechanical properties
KW - X-ray computed tomography (XCT)
KW - Porosity
KW - Anisotropy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625655
DO - https://doi.org/10.1007/s40964-025-00972-2
SN - 2363-9520
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-62565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis
A1 - Shakeel, Y.
A1 - Gedsun, A.
A1 - Forti, M.
A1 - Hunke, S.
A1 - Han, Ying
A1 - Hammerschmidt, T.
A1 - Aversa, R.
A1 - Olbricht, Jürgen
A1 - Chmielowski, M.
A1 - Stotzka, R.
A1 - Bitzek, E.
A1 - Hickel, Tilmann
A1 - Skrotzki, Birgit
T1 - Management of reference data in materials science and engineering exemplified for creep data of a single-crystalline Ni-based superalloy
N2 - The identification of process-structure-property relationships of materials inevitably requires the combination of research data from different measurements. Therefore, the concepts related to FAIR (findable, accessible, interoperable, reusable) data handling, increasingly reported in literature, are particularly important in the materials science and engineering domain. However, they have not yet been integrated into a single, overarching methodological framework, particularly for reference data. Here, we introduce such a framework. Our concept covers data generation, documentation, handling, storage, sharing, data search and discovery, retrieval, and usage. Furthermore, we prototypically implement it using a real dataset with creep data of a single-crystal CMSX-6 Ni-based superalloy. The presented implementation is traceable and permanently accessible through open repositories. The individual elements considered in the framework ensure the functionality and usability of the data and, thus, the adherence to the FAIR principles. In conjunction with this, we present a definition for reference data of materials. Our definition underlines particularly the importance of a comprehensive documentation, e.g., on material provenance, data processing procedures, and the software and hardware used, including software-specific input parameters, as these details enable data users or independent parties to assess the quality of the datasets and to reuse and reproduce the results. Reference data that is managed according to the proposed framework can be used to advance knowledge in the materials science and engineering domain, e.g., by identifying new process-structure-property relations.
KW - Referenzdaten
KW - NFDI-MatWerk
KW - Data schema
KW - Research Data Management
KW - Reference Data
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625047
DO - https://doi.org/10.1016/j.actamat.2025.120735
VL - 286
SP - 1
EP - 15
PB - Elsevier Inc.
AN - OPUS4-62504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Anker, A. S.
A1 - Annadurai, V.
A1 - Balazs, D. M.
A1 - Bienert, Ralf
A1 - Bouwman, W. G.
A1 - Breßler, Ingo
A1 - Breternitz, J.
A1 - Brok, E. S.
A1 - Bryant, G.
A1 - Clulow, A. J.
A1 - Crater, E. R.
A1 - De Geuser, F.
A1 - Del Giudice, A.
A1 - Deumer, J.
A1 - Disch, S.
A1 - Dutt, S.
A1 - Frank, K.
A1 - Fratini, E.
A1 - Garcia, P. R. A. F.
A1 - Gilbert, E. P.
A1 - Hahn, Marc Benjamin
A1 - Hallett, J.
A1 - Hohenschutz, M.
A1 - Hollamby, M.
A1 - Huband, S.
A1 - Ilavsky, J.
A1 - Jochum, J. K.
A1 - Juelsholt, M.
A1 - Mansel, B. W.
A1 - Penttilä, P.
A1 - Pittkowski, R. K.
A1 - Portale, G.
A1 - Pozzo, L. D.
A1 - Rochels, L.
A1 - Rosalie, Julian
A1 - Saloga, Patrick E. J.
A1 - Seibt, S.
A1 - Smith, A. J.
A1 - Smith, G. N.
A1 - Spiering, G. A.
A1 - Stawski, Tomasz M.
A1 - Taché, O.
A1 - Thünemann, Andreas
A1 - Toth, K.
A1 - Whitten, A. E.
A1 - Wuttke, J.
T1 - The human factor - Results of a small-angle scattering data analysis round robin
N2 - A round-robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5% and half of the population width entries within 40%. Due to the added complexity of the structure factor, far fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 and 86%, respectively. This round-robin experiment highlights several causes for the discrepancies, for which solutions are proposed.
KW - Round Robin
KW - Data analysis
KW - Small-angle scattering
KW - Nanomaterials
KW - Interlaboratory comparability
KW - Nanostructure quantification
KW - Methodology
KW - MOUSE
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587091
DO - https://doi.org/10.1107/S1600576723008324
SN - 1600-5767
VL - 56
IS - 6
SP - 1618
EP - 1629
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Rosalie, Julian
A1 - Pauw, Brian R.
A1 - Hohenwarter, Anton
T1 - Precipitate size evolution in an ultrafine-grained magnesium-manganese alloy
N2 - Precipitate size evolution during room temperature high-pressure torsion (HPT) of a Mg-1.35wt.%Mn alloy was studied using scanning transmission electron microscopy (STEM) and Small-/Wide-angle X-ray scattering (SAXS/WAXS). The volume fraction of the nm-scale α-Mn particles increased with applied strain, however small angle X-ray scattering (SAXS) indicated that the majority of manganese remained in solution even after 10 HPT rotations, indicating that the reaction progress is still limited by the diffusivity of Mn. Analysis of the precipitate size distribution determined that the mean particle size did not increase over the course of HPT. This, in combination with the precipitate size distribution suggested that precipitate growth was subject to interfacial rather than diffusional control.
KW - Severe plastic deformation
KW - High-pressure torsion
KW - Ultrafine-grained alloys
KW - Magnesium
KW - Grain-boundary pinning
KW - Precipitate growth
KW - Interface control
KW - Diffusional control
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653422
DO - https://doi.org/10.48550/arXiv.2601.05619
SP - 1
EP - 15
AN - OPUS4-65342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Theoretical study of influence of electromagnetic stirring on transport phenomena in wire feed laser beam welding
N2 - The additional element from the filler wire in the laser beam welding is usually distributed inhomogeneously in the final weld due to the high solidification rate of weld pool. It has been found that the electromagnetic stirring produced by an external oscillating magnetic field can enhance the material mixing in the weld pool to achieve a more uniform element distribution. However, the magnetic field has a highly nonlinear and multicoupled interaction with the weld pool behavior, which makes the quantitative explanation of the physical mechanism difficult. In this study, the effect of electromagnetic stirring on the transport phenomena in the wire feed laser beam welding is investigated by a numerical modeling. A 3D transient multiphysical model considering the magnetohydrodynamics, heat transfer, fluid flow, keyhole dynamics, and element transport is developed. The multiple reflections and the Fresnel absorption of the laser on the keyhole wall are calculated using the ray tracing method. The numerical results show that a Lorentz force produced by the oscillating magnetic field and its induced eddy current gives significant influence on the transport phenomena in the molten pool. The forward and downward flow is enhanced by the electromagnetic stirring, which homogenizes the distribution of the additional elements from a nickel-based filler wire in a steel weld pool. The numerical results show a good agreement with the high-speed images of the molten pool, the fusion line from the optical micrograph, and the element distribution from the energy dispersive x-ray spectroscopy. This work provides a physical base for the electromagnetic-controlled laser beam welding and some guidance for the selection of electromagnetic parameters.
KW - Magnetohydrodynamics
KW - Molten pool dynamics
KW - Element transport
KW - Laser beam welding
PY - 2020
DO - https://doi.org/10.2351/7.0000069
VL - 32
IS - 2
SP - 022026-1
EP - 022026-9
AN - OPUS4-50874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
T1 - The influence of aging and mean stress on fatigue of Al-alloy EN AW-2618A
N2 - In this study, the influence of aging and mean stress on fatigue of the aluminium-alloy EN AW-2618A is investigated. Therefore axial fatigue tests are carried out on smooth specimens. The experiments show that the fatigue life decreases with increasing mean stress. Furthermore, the tests with the overaged specimens demonstrate that the number of cycles to failure is decreasing with increasing aging time.
T2 - LCF9
CY - Berlin, Germany
DA - 21.06.2022
KW - Fatigue
KW - Aluminium alloy
KW - EN AW-2618A
KW - Damage Behavior
PY - 2022
AN - OPUS4-55125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Ermittlung des intrinsischen Schwellenwerts und dessen Validierung als Werkstoffparameter
N2 - Zuverlässige Rissfortschrittsdaten sind notwendig für die sichere Bewertung zyklisch beanspruchter Bauteile. Diese werden häufig im Schwellenwertbereich betrieben, daher ist die genaue experimentelle Ermittlung der Schwellenwerte gegen Rissausbreitung wichtig, um die Unsicherheit der Lebensdauerprognose zu minimieren. Viele Faktoren können die experimentellen Ergebnisse beeinflussen, u.a. die Versuchsparameter und die Umgebungsbedingungen. Diese Arbeit zeigt, dass der intrinsische Schwellenwert von der experimentellen Verfahren und von der Umgebung unabhängig ist. Daraus kann man schließen, dass der intrinsische Schwellenwert als Werkstoffparameter betrachtet werden kann.
T2 - Workshop Schwellenwert
CY - Munich, Germany
DA - 26.02.2026
KW - Schwingbruchmechanik
KW - Schwellenwert
KW - Rissfortschritt
KW - Umgebungseffekte
PY - 2026
AN - OPUS4-65646
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Der Schwellenwert der da/dN-∆K-Kurve als Auslegungskriterium für die Bauteilbewertung
N2 - Für die Bestimmung der Restlebensdauer zyklisch beanspruchter Bauteile kommt dem Schwellenwert für Ermüdungsrissausbreitung ΔKth und dem sich anschließenden Schwellenwertbereich der dadN⁄-ΔK-Kurve große Bedeutung zu. Dem stehen Unsicherheiten bei der Bestimmung und Analyse gegenüber. Der Aufsatz befasst sich mit der Ermittlung des sogenannten intrinsischen Schwellenwerts, der als robuster Eingangsparameter für eine „rissschließfreie“ Analyse der Restlebensdauer von entscheidender Bedeutung ist.
T2 - Tagung Werkstoffprüfung 2020
CY - Online meeting
DA - 03.12.2020
KW - Intrinsischer Schwellenwert gegen Ermüdungsrissausbreitung
KW - Schadenstolerante Bauteilauslegung
KW - Restlebensdauer
PY - 2020
AN - OPUS4-51754
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Anker, A. S.
A1 - Balazs, D. M.
A1 - Beyer, F. L.
A1 - Bienert, Ralf
A1 - Bouwman, W. G.
A1 - Breßler, Ingo
A1 - Breternitz, J.
A1 - Brok, E. S.
A1 - Bryant, G.
A1 - Clulow, A. J.
A1 - Crater, E. R.
A1 - De Geuser, F.
A1 - Giudice, A. D.
A1 - Deumer, J.
A1 - Disch, S.
A1 - Dutt, S.
A1 - Frank, K.
A1 - Fratini, E.
A1 - Gilbert, E. P.
A1 - Hahn, Marc Benjamin
A1 - Hallett, J.
A1 - Hohenschutz, Max
A1 - Hollamby, M. J.
A1 - Huband, S.
A1 - Ilavsky, J.
A1 - Jochum, J. K.
A1 - Juelsholt, M.
A1 - Mansel, B. W.
A1 - Penttilä, P.
A1 - Pittkowski, R. K.
A1 - Portale, G.
A1 - Pozzo, L. D.
A1 - Ricardo de Abreu Furtado Garcia, P.
A1 - Rochels, L.
A1 - Rosalie, Julian
A1 - Saloga, P. E. J.
A1 - Seibt, S.
A1 - Smith, A. J.
A1 - Smith, G. N.
A1 - Annadurai, V.
A1 - Spiering, G. A.
A1 - Stawski, Tomasz
A1 - Taché, O.
A1 - Thünemann, Andreas
A1 - Toth, K.
A1 - Whitten, A. E.
A1 - Wuttke, J.
T1 - The human factor - Results of a small-angle scattering data analysis round robin
N2 - A Round Robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions, and two from powders.
Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5 % and half of the population width entries within 40 %, respectively. Due to the added complexity of the structure factor, much fewer people submitted answers on the powder datasets.
For those that did, half of the entries for the means and widths were within 44 % and 86 % respectively. This Round Robin experiment highlights several causes for the discrepancies, for which solutions are proposed.
KW - Round robin
KW - Sall-angle scattering
KW - Nanostructure quantification
KW - Nanostructure
KW - SAXS
KW - MOUSE
KW - X-ray scattering
KW - Size distribution
KW - Nanoparticles
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571342
DO - https://doi.org/10.48550/arXiv.2303.03772
SP - 1
EP - 23
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-57134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - The effect of an AC magnetic field on flow dynamics and filler wire mixing in high power laser hybrid welding
N2 - The use of the oscillating magnetic field as a backing support for the welding of thick components is already known. The influence of the magnetic field and the induced Lorentz forces in the melt on the melt pool geometry and the fluid flows is not yet fully investigated. The study deals with the determination of the influence of an externally applied oscillating magnetic field on the melt pool dynamics in high power laser hybrid welding process. An AC magnet was positioned under the specimen to create an electromagnetic force directed upwards to oppose dropping. To visualise the flow characteristics of the melt, several experiments were carried out using a technique specifically designed for this purpose with mild steel made of S355J2 with a wall thickness of 20 mm and a quartz glass in a butt configuration. A high-speed camera was used to monitor the geometry of the melt pool through the glass. The influence of the magnetic field orientation to the welding direction and the oscillation frequency on the molten pool was investigated for the case of the metal-glass configuration and for laser hybrid welding. The high-speed recordings were analysed with the Optical Flow Algorithm to characterise the flow within the melt pool. The element distribution over the whole seam thickness was evaluated by X-ray fluorescence (XRF). The high-speed analysis showed that in the melt pool two vortices are formed, one in the upper part and the other in the lower part. In the region where the two vortices come together, a narrow region (necking region) forms in the melt pool. The evaluation of the high-speed recordings shows that the depth of the region where the two vortices meet is strongly influenced by the oscillation frequency. Additionally, the oscillation frequency demonstrated a greater influence on the melt pool dynamics and the mixing of the elements of the filler wire.
T2 - X International Conference «Beam Technologies & Laser Application»
CY - Pushkin (St. Petersburg), Russia
DA - 20.09.2021
KW - Hybrid laser arc welding
KW - Laser beam welding
KW - Material transport
PY - 2021
AN - OPUS4-53573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Darvishi Kamachali, Reza
A1 - Wang, Lei
A1 - Lin, L. L.
A1 - Manzoni, Anna Maria
A1 - Skrotzki, Birgit
A1 - Thompson, G. B.
T1 - CALPHAD-informed density-based grain boundary thermodynamics
N2 - The Gibbs free energy of a grain boundary is a complex thermodynamic function of temperature, pressure, and composition. These complexities add to the intrinsic crystallographic and chemical constraints imposed by the adjacent bulk phase. Recently we have proposed a density-based model for assessing grain boundary thermodynamics that enables a CALPHAD-informed description of the grain boundary. As such, the Gibbs free energy of the grain boundary is directly linked with available CALPHAD thermodynamic data. In this talk, new aspects of interfacial segregation and phase transformation are revealed by benchmarking the current model for various experimental cases, including several steels, high-entropy alloys and aluminum alloys. The effects of elastic interactions on the grain boundary segregation and the application of the model to a nanocrystalline Pt-Au alloy, with numerous grain boundaries of various characters, will be discussed.
T2 - DPG (Deutsche Physiker Gesellschaft)
CY - Online meeting
DA - 27.09.2021
KW - Density-based model
KW - Defects thermodynamics
KW - Defects phase diagram
KW - CALPHAD
KW - Crystal Defects
PY - 2021
AN - OPUS4-53556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosalie, Julian
A1 - Hohenwarter, A.
T1 - Dynamic Precipitation during High-Pressure Torsion of a Magnesium–Manganese Alloy
N2 - An ultrafine-grained magnesium alloy has been produced through room temperature high-pressure torsion (HPT) of solutionized Mg–1.35 wt% Mn. Dynamic precipitation of nanometer-scale Mn particles occurs during deformation. These particles populate the grain boundaries, acting as pinning sites which allow the alloy to develop a grain size of 140 nm after 0.5 rotations. Further, HPT deformation results in a gradual increase in grain size with no increase in precipitate size. Despite the extensive deformation applied, the alloy does not develop a bimodal grain structure and retains a grain size of 230 nm after 10 complete rotations, demonstrating the stability and effectiveness of these pinning particles.
KW - Grain-boundary pinning
KW - Magnesium alloys
KW - High-pressure torsion
KW - Severe plastic deformation
KW - Ultrafine-grained materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656471
DO - https://doi.org/10.1002/adem.202500424
SN - 1527-2648
VL - 28
IS - 4
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-65647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eisenbart, M.
T1 - Development of an ontology for the lifecycle of copper and copper alloys
N2 - Efforts towards digitalization in the material science and technology community have enhanced in the last years. In 2019 the German digitalization initiative platform „MaterialDigital“1 (MD) has been started. Numerous projects concerning digitalization, including the copper related project „KupferDigital“ (copper digital) have been initiated under the umbrella of MD. The initiative strives to
address numerous issues concerning data access, exchange, security, provenance and sovereignty. Heterogeneous data origin, storage and evaluation often result in problems concerning comparability and reproducibility of scientific and technological results. In many cases material data are recorded, but the methods of testing are insufficiently described, or such information is not communicated along with the raw data. The material data can also have numerous different formats such as paper printouts, pdfs, excel sheets or csv-files. Hence, gathering and integrating material data from different sources is challenging for potential users like materials scientists and engineers, especially if there are contradictory data where the reasons for contradictions is not clear due their vague description. In order to address these problems, data should comply to the so called „FAIR“ principle which calls for data to be findable, accessible, interoperable, and reusable (FAIR)2 and hence be accessible via so-called decentralized but interconnected data spaces. By using knowledge representation withontologies, data can be enriched with meaning and the methods of the testing procedures can be accurately provided. In this presentation we want to introduce our approach to such knowledge representation based on a high-throughput alloy development process for Cu-based alloys³ along with characterization techniques such as hardness testing and microstructural characterization (e.g. EBSD – Electron Backscattered Diffraction).
T2 - Copper Alloys Conference
CY - Dusseldorf, Germany
DA - 22.11.2022
KW - Copper
KW - Life cycle
KW - Ontology
PY - 2022
AN - OPUS4-56406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Fedelich, Bernard
A1 - Olbricht, Jürgen
A1 - Skrotzki, Birgit
A1 - Jokisch, T.
ED - Zimmermann, M.
T1 - Rissfortschrittsuntersuchungen an gefügten Nickelbasiswerkstoffen bei hoher Temperatur
N2 - In nickelbasierten Superlegierungen, die für Gasturbinenschaufeln verwendet werden, sind bei hohen Betriebstemperaturen und -belastungen Kriechschäden, Ermüdung, Korrosion und Oxi-dation zu beobachten. Die betroffenen Turbinenschaufeln müssen ersetzt oder repariert werden, um Effizienzverluste und ein eventuelles Bauteilversagen zu vermeiden. In letzter Zeit wurden additive Fertigungs- und Lötverfahren für die Reparatur und das Fügen von Nickelbasiswerk-stoffen entwickelt, um die Einschränkungen der traditionellen Reparaturverfahren zu überwinden. Für eine auslegungsrelevante Bewertung des Risswachstumsverhaltens in den Fügezonen, die durch diese neuen Technologien erzeugt werden, sind Rissfortschrittsuntersuchungen erfor-derlich. Entsprechende Untersuchungen an gefügten Proben werden in diesem Beitrag vorge-stellt. Die Rissfortschrittsversuche werden an gefügten SEN-Proben (Single Edge Notch) bei einem Spannungsverhältnis von 0,1 und einer Temperatur von 950 °C durchgeführt. Das Riss-wachstum wird mit der DCPD-Methode (Direct Current Potential Drop) überwacht, und die ge-messenen Potenzialsignale werden anhand der optisch vermessenen Risslänge und einer Finite-Elemente-Analyse kalibriert. Der Spannungsintensitätsfaktor (SIF) für die gefügte SEN-Geometrie wird mit Hilfe von Finite-Elemente-Analysen berechnet. Auf diese Weise können Rissfortschrittskurven aus den experimentellen Daten abgeleitet werden.
T2 - Tagung „Werkstoffprüfung 2022“
CY - Dresden, Germany
DA - 27.10.2022
KW - Lötverbindung
KW - Rissfortschritt
KW - SEN-Probe
KW - Gefügte Nickelbasislegierungen
PY - 2022
SN - 978-3-88355-430-3
VL - 2022
SP - 67
EP - 72
AN - OPUS4-57090
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Phonon workflow and applications
N2 - This talk introduced the participants to phonons and how they are typically computed. Then, I introduced the participants to the harmonic phonon, the Grüneisen, and the quasi-harmonic workflow that allows the computation of properties related to phonons. I also had detailed examples of how these workflows can be used in practice. Beyond this, I showed how these workflows can be used to automatically benchmark interatomic potentials and use them for the development of such potentials.
T2 - "Automated ab initio workflows with Jobflow and Atomate2" CECAM Flagship school
CY - Lausanne, Switzerland
DA - 17.03.2025
KW - Automation
KW - Phonons
KW - Thermal Conductivity
KW - Machine Learning
KW - Software Development
KW - Machine Learned interatomic Potentials
PY - 2025
AN - OPUS4-62949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Avila Calderon, Luis Alexander
T1 - On the role of the manufacturing-induced cell structure in laser-powder-bed-fused stainless steel 316L during cyclic plastic deformation
N2 - The room temperature cyclic plastic deformation behavior of stainless steel 316L produced by laser powder bed fusion and heat treated to two microstructural conditions was investigated in strain-controlled incremental-step-test low-cycle fatigue experiments. The heat treatments were performed at 450 °C for 4 h and at 900 °C for 1 h. The lower temperature heat treatment retains the cell structure present in the as-built material. The higher temperature heat treatment leads to disappearance of the cell structure and a decreased proof strength. Both investigated heat treatment conditions exhibited cyclic softening. In the condition heat treated at 900 °C for 1 h, the ability of the cell structure to act as barrier against plastic deformation when cyclically strained is degraded, which is reflected in the reduction of the cyclic yield strength. In that same condition, the cyclic softening was less pronounced. The presence or absence of the manufacturing-induced cell structure seems to determine the slip mode. When present, the microstructural evidence points to a planar slip behavior. After heat treatment at 900 °C for 1 h, which led to its dissolution, microstructural investigations revealed a wavy slip behavior, which has been also reported for the conventionally manufactured 316L counterpart [1]. In this case, the formation of low-energy dislocation structures acts as softening agent.
T2 - Additive Manufacturing 2026
CY - Kassel, Germany
DA - 25.03.2026
KW - AGIL
KW - Additive Fertigung
KW - Low-Cycle-Fatigue
KW - 316L
KW - Mikrostruktur
PY - 2026
AN - OPUS4-65746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Verknüpfung von Datenrepositorien: Die Plattform MaterialDigital (PMD)
N2 - Vorstellung der Plattform MaterialDigital. Darstellung der Bedürfnisse und Herausforderungen in der Materialwissenschaft und Werkstofftechnik.
T2 - Vision Keramik
CY - Dresden, Germany
DA - 07.06.2022
KW - Digitalisierung
KW - Ontologie
KW - Standardisierung
PY - 2022
AN - OPUS4-54979
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winterkorn, René
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Lichtbogenbasierte additive Fertigung dickwandiger Strukturen aus einer höherfesten Al-Mg-Si-Aluminiumlegierungen
N2 - Die lichtbogenbasierte, additive Fertigung ist dank hoher erreichbarer Aufbauraten und nahezu uneingeschränktem Bauraum zur Fertigung großvolumiger Bauteile prädestiniert. Die Kombination etablierter Maschinenkomponenten aus Robotertechnik, Schweißtechnik und Sensorik ermöglicht den präzisen schichtweisen Materialauftrag. Die Wirkmechanismen zwischen Prozessparametern und den daraus resultierenden mechanisch-technologischen Eigenschaften der additiv gefertigten Bauteile stellen eine Herausforderung dar. Dies gilt insbesondere auch für dickwandige Bauteile. Bei der Fertigung von Bauteilen aus höherfesten Al-Mg-Si-Aluminiumlegierungen ist aufgrund der hohen Anfälligkeit für Erstarrungsrisse und der Neigung zu wasserstoffinduzierter Porosität im besonderen Maße auf das Temperaturregime und die gewählte Aufbaustrategie zu achten.
Der Einfluss der Prozessparameter auf die Bauteilqualität wurde durch die Analyse der Größe und Verteilung von Poren sowie der resultierenden Festigkeit untersucht. Darüber hinaus wurde der Einfluss einer Wärmenachbehandlungsstrategien auf das Festigkeitsverhalten analysiert. Es konnte gezeigt werden, dass dickwandige Strukturen aus höherfesten Al-Mg-Si-Aluminiumlegierungen mit mechanischen Kennwerten im Bereich des Referenzmaterials mittels MSGLichtbogenverfahren additiv gefertigt werden können.
T2 - Additive Fertigung – Werkstoffe – Prozesse – Wärmebehandlung 2022
CY - Bremen, Germany
DA - 29.06.2022
KW - WAAM
KW - Al-Mg-Si-Legierungen
KW - Porosität
KW - Wärmenachbehandlung
KW - Mechanisch technologische Kennwerte
PY - 2022
SP - 169
EP - 181
PB - Arbeitsgemeinschaft Wärmebehandlung und Werkstofftechnik e. V.
CY - Bremen
AN - OPUS4-56673
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Microstructure Based Study on the Low Cycle Fatigue Behavior of Stainless Steel 316L manufactured by Laser Powder Bed Fusion
N2 - Due to the advantages of Laser Powder Bed Fusion (PBF-LB), i.e., design freedom and the possibility to manufacture parts with filigree structures, and the considerable amount of knowledge available for 316L in its conventional variant, the mechanical behavior, and related microstructure-property relationships of PBF-LB/316L are increasingly subject of research. However, many aspects regarding the - application-relevant - mechanical behavior at high temperatures are not yet fully understood. Here, we present the results of an experimental study on the LCF behavior of PBF-LB/316L featuring a low defect population, which makes this study more microstructure-focused than most of the studies in the literature. The LCF tests were performed between room temperature (RT) and 600 °C. The mechanical response is characterized by strain-life curves, and hysteresis and cyclic deformation curves. The damage and deformation mechanisms are studied with X-ray computed tomography, and optical and electron microscopy. The PBF-LB/M/316L was heat treated at 450 °C for 4 h, and a hot‑rolled (HR) 316L variant with a fully recrystallized equiaxed microstructure was tested as a reference. Besides, selected investigations were performed after a subsequent heat treatment at 900 °C for 1 h. The PBF-LB/316L exhibits higher cyclic stresses than HR/316L for most of the fatigue life, especially at room temperature. At the smallest strain amplitudes, the fatigue lives of PBF-LB/M/316L are markedly shorter than in HR/316L. The main damage mechanisms are multiple cracking at slip bands (RT) and intergranular cracking (600 °C). Neither the melt pool boundaries nor the gas porosity have a significant influence on the LCF damage mechanism. The cyclic stress-strain deformation behavior of PBF-LB/M/316L features an initial hardening followed by a continuous softening. The additional heat treatment at 900 °C for 1 h led to decreased cyclic stresses, and a longer fatigue life.
T2 - 4th Symposium on Materials and Additive Manufacturing
CY - Berlin, Germany
DA - 12.06.2024
KW - AGIL
KW - 316L
KW - Microstructure
KW - Low Cycle Fatigue
KW - Heat Treatment
KW - Laser Poeder Bed Fusion
PY - 2024
AN - OPUS4-60432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Singh, Shobhit
T1 - Accelerated Creep Testing in High- Temperature Alloys
N2 - This study introduces an innovative method for efficiently determining the creep properties of high-temperature materials through high-throughput testing, employing digital image correlation [1,2]. The focus is on the AlCoCrFeNiTi alloy [3-5], synthesized by directional solidification, known for its exceptional strength and unique properties. Experimental investigations, including compression, and bending creep tests, were conducted at 750°C.
Capitalizing on the inhomogeneous stress and strain distribution within a cantilever subjected to bending, we leverage this characteristic to extract multiple creep curves from a single test. Stresses at key points were determined using existing analytical solutions [5,6]. Uniaxial tests spanning 300 to 500 MPa initial stress were complemented by bending tests designed to induce similar stress levels. A detailed comparison between bending and uniaxial creep is presented, including the results of verification studies on additional alloys.
This methodology not only expedites testing but also minimizes material usage, energy consumption, and manual labour. This research showcases a reliable and time-efficient approach to exploring the creep behavior of high-temperature materials. The technique is particularly advantageous for characterizing precious alloys with limited dimensions. Microstructural heterogeneity may exist in specimens tested under bending load, however, it can still be correlated to the mechanical properties with modern high-resolution characterization methods. Stress and resulting strain can be directly compared in a single specimen, ensuring uniform manufacturing, and heating history. This method eliminates the possible errors due to testing with different rigs, which could impair the accuracy of studies based on individual tests.
T2 - International Conference on Creep and Fracture of Engineering Materials and Structures
CY - Bengaluru, KA, India
DA - 28.07.2024
KW - Digital Image Correlation
KW - Creep
KW - High-Temperature Materials
PY - 2024
AN - OPUS4-60925
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Teske, Tanita
T1 - Untersuchung des Potentials des Kaltgasspritzens für die Reparatur zyklisch belasteter Bauteile
N2 - Das Kaltgasspritzen als Reparaturverfahren bietet die Möglichkeit den teuren Austausch beschädigter Bauteile in der Luft- und Raumfahrt zu vermeiden. In dieser Arbeit wurden das Potential an der Aluminiumlegierung AL6061-T6, unter Verwendung von Stickstoff als Prozessgas, untersucht. Mit Fokus auf das In-situ Kugelstrahlen, zur Verbesserung der mechanischen Eigenschaften, wurden quasi-statische Zugversuche und einachsige Zeitfestigkeitsversuche durchgeführt. Im Ergebnis zeigte sich die Verbesserung der Adhäsion zwischen Grundwerkstoff und aufgebrachten Material als entscheidendes Kriterium für eine erfolgreiche Anwendung. Zur Verbesserung der Adhäsion wurden die Substratoberflächen laserstrukturiert und der Einfluss mit Adhäsionsversuchen überprüft.
T2 - 9. Tagung des DVM-Arbeitskreises Additiv gefertigte Bauteile und Strukturen
CY - Stuttgart, Germany
DA - 06.11.2024
KW - Kaltgasspritzen
KW - Reparatur
KW - Ermüdungsfestigkeit
KW - Laserstrukturierung
KW - Luft- und Raumfahrt
PY - 2024
AN - OPUS4-63179
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Creep Behavior of Stainless Steel 316L Manufactured by Laser Powder Bed Fusion
N2 - The broader industrial adoption of metal AM in safety-critical applications is limited, among others, by the still in-sufficient understanding of process–structure–property relationships and a lack of reliable mate-rial data. The content presented here approaches this limitation regarding the creep behavior of one of the most studied AM alloys: PBF-LB/M/316L stainless steel. A nearly as-built and a condition heat treated at 900 °C for 1 h, along with a conventionally manufactured variant are investigated. The creep behavior until reaching the minimum creep rate is mainly determined by the solidification cell structure. The damage is overall mainly intergranular, independent of the heat treated condition. The heat treatment at 900 °C for 1 h partially influenced the microstructure (mainly in terms of cell
structure). The creep behavior until reaching the minimum creep rate remained nearly unchanged. The creep lifetime and ductility were enhanced. The crystallographic texture evolved after creep deformation.
T2 - TMS 2025 Annual Meeting & Exhibition
CY - Las Vegas, NV, USA
DA - 23.03.2025
KW - AGIL
KW - Creep
KW - 316L
KW - Microstructure
PY - 2025
AN - OPUS4-63456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Neue Wege in der Materialforschung: Zusammenspiel von Hochdurchsatz-Simulationen und maschinellem Lernen
N2 - Dies ist meine Antrittsvorlesung an der Friedrich-Schiller-Universität Jena, die im Rahmen der BAM-Universität-Jena-Kooperation entstanden ist. Hier stelle ich die Materialinformatik und unsere Forschung im speziellen vor.
T2 - Antrittsvorlesung an der Friedrich-Schiller-Universität Jena
CY - Jena, Germany
DA - 20.01.2025
KW - Automation
KW - Ab initio
KW - Machine learning
KW - Phonons
KW - Materialdesign
KW - Materials Acceleration Platforms
PY - 2025
AN - OPUS4-62437
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
T1 - Burst behaviours of aero-engine turbine disk at overspeed conditions
N2 - This presentation focuses on the basic ideas and current status of the development of an arithmetical method to predict the failure rotational speed of turbine disks. The certification specification requires that a gas turbine aero-engine must hold 5 minutes at overspeed conditions without critical failure. Therefore, instead of experimental proof from spin-tests using test-disks similar to engine components, it is considered to use simple specimen with similar test conditions compared to real overspeed scenarios. These test conditions, or stress fields are determined using arithmetical method, e.g. finite element method, with consideration of fracture mechanics under quasi-static conditions with a given rotational speed.
Failure modes like hoop burst and rim peeling are considered during determination of stress fields. Various crack-tip parameters are used to explore the similarity of stress field between simple specimen and real overspeed scenarios. Additionally, probabilistic aspects and the implementation of a global stability criterion for overspeed analysis are also considered.
T2 - 43rd Materials Mechanics Seminar
CY - Sani, Chalkidiki, Greece
DA - 06.06.2022
KW - Structural integrity
KW - Fracture mechanics
KW - Turbine disk
KW - Overspeed
PY - 2022
AN - OPUS4-55081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Jonathan
T1 - Visual surface structure analysis of high-resolution images from visual in-situ process monitoring in laser powder bed fusion
N2 - Parameter studies are a common step in selecting process parameters for powder bed fusion of metals with laser beam (PBF-LB/M). Density cubes manufactured with varied process parameters exhibit distinguishable surface structures visible to the human eye. Industrial visual in-situ monitoring systems for PBF-LB/M currently have limited resolution and are incapable of reliably capturing differences in the surface structures. For this work, a 65 MPixel high resolution monochrome camera is integrated in an industrial PBF-LB/M machine together with a high intensity led bar. Post-exposure images are taken to analyze differences in light reflection on the specimen’s surface. The grey level co-occurrence matrix is used to quantify the in-situ measured visual surface structure of nickel-based super alloy IN939 density cubes. The properties of the grey level co-occurrence matrix correlate to the energy input and resulting porosity of specimens. Low energy samples with lack of fusion flaws show an increased contrast in the grey level co-occurrence matrix compared to specimens with an optimal energy input. The potential of high-resolution images as reference data in in-situ process monitoring in PBF-LB/M is discussed.
T2 - 77th IIW Annual Assembly and International Conference
CY - Rhodos, Greece
DA - 06.07.2024
KW - Additive manufacturing
KW - Powder bed fusion
KW - In-situ monitoring
KW - Image processing
KW - Lack of fusion
PY - 2024
AN - OPUS4-60688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
T1 - Numerical analysis of the effect of an oscillating metal vapor plume on the keyhole and molten pool behavior during deep penetration laser beam welding
N2 - The effect of the oscillating metal vapor plume on the keyhole and molten pool behavior during the laser beam welding of AlMg3 aluminum alloys is investigated by experimental and numerical methods. The real-time height of the metal vapor plume is measured by high-speed camera observation. The obtained experimental results are used to evaluate the additional heating source and laser beam attenuation caused by the scattering and absorption based on the Beer–Lambert theory. Furthermore, the dynamic behavior of the metal vapor plume is incorporated into a 3D transient heat transfer and fluid flow model, coupled with the ray tracing method, for the laser beam welding of the AlMg3 alloy. It is found that additional heating resulting from the scattered and absorbed laser beam energy by the metal vapor plume significantly expands the shape of the molten pool on the top region. Moreover, the oscillating metal vapor plume caused the fluctuation of the high-temperature region in the molten pool. The probability of keyhole collapse at the bottom increases 17% due to the oscillating laser power induced by the laser beam attenuation. The internal interplay between the metal vapor plume, molten pool shape, and keyhole collapse is obtained. The developed model has been validated by experiments, which shows a good agreement.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Oscillating vapor plume
KW - Keyhole collapse
PY - 2023
AN - OPUS4-58794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bär, J.
A1 - Kanna, N.K.
A1 - Duarte, Larissa
A1 - Madia, Mauro
T1 - Determination of the Kitagawa-Takahashi Diagram using DC Potential Drop Measurements
N2 - The Kitagawa-Takahashi Diagram is an important tool for describing the fatigue limit of components containing defects. The models used for its description differ, particularly in the transition region corresponding to the short crack regime. Therefore, for a reliable statement about the fatigue limit in this area, an experimental validation of the models is necessary. However, the standardized staircase method requires a large number of samples and has a long test duration. In this work, a method is presented that allows a simpler and faster validation of the Kitagawa-Takahashi Diagram in the region of short cracks. Rectangular notches with a defined width and depth were manufactured in flat samples of a low-alloyed steel with two different heat treatments using an engraving laser. This method allows a rapid production of very sharp notches without plastic deformation and with only a slight thermal influence on the surrounding material. The samples prepared in this way were fatigued with block wise increasing loads until failure. Cracks are detected by means of a Direct Current Potential Drop method. The length of the loading block (number of cycles) is determined by the measured potential drop. This procedure enables a reliable and precise determination of the limit stress for the respective notch size with low experimental effort and time consumption. The tests have
shown that in case of the normalized steel none of the models describes the determined values for the fatigue limit. For the hardened steel, the plot of the fatigue limit as a function of the Murakami parameter √area in combination with the El Haddad model allows a satisfactory description of the measured values.
T2 - 5th International Symposium on Fatigue Design and Material Defects
CY - Trento, Italy
DA - 14.05.2025
KW - Kitagawa-Takahashi diagram
KW - Damage tolerance
KW - Fatigue
KW - Potential drop
KW - Fracture mechanics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655519
DO - https://doi.org/10.1016/j.prostr.2025.12.283
VL - 76
SP - 27
EP - 34
PB - Elsevier B.V.
AN - OPUS4-65551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Hybrid laser-arc welding of thick-walled pipe segments with optimization of the end crater
N2 - The study deals with the application of the high-power hybrid-laser arc welding process on up to 15 mm thick pipe segments with the intention to avoid end crater imperfections during closing of the circumferential welds, where the pipes were turned during welding in 1G- and 2G-positions. Different techniques such as laser power ramp-down, abrupt switch-off of the laser power and change of the magnification of the laser spot diameter and defocusing of the laser beam relative to the workpiece were tested to remove the laser energy from the process. It could be shown that a high defocusing of the optic system above 40 mm with a resulting beam diameter > 2.9 mm in a short overlap length of approx. 20 mm leads to the formation of a cup-shaped weld seam, which is preferred for avoidance of cracks and pores in the end crater. A laser optics with motor-driven lens system was used for the welding experiments to defocuse the laser beam without changing the position of the arc.
T2 - 11th CIRP Conference on Photonic Technologies LANE 2020
CY - Online Meeting
DA - 07.09.2020
KW - End crater
KW - Hybrid laser-arc welding
KW - Circumferential weld
PY - 2020
AN - OPUS4-51634
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Anker, Andy S.
A1 - Aspuru-Guzik, Alán
A1 - Ben Mahmoud, Chiheb
A1 - Bennett, Sophie
A1 - Briling, Ksenia R.
A1 - Changiarath, Arya
A1 - Chong, Sanggyu
A1 - Collins, Christopher M.
A1 - Cooper, Andrew I.
A1 - Crusius, Daniel
A1 - Darmawan, Kevion K.
A1 - Das, Basita
A1 - David, Nicholas
A1 - Day, Graeme M.
A1 - Deringer, Volker L.
A1 - Duarte, Fernanda
A1 - Eardley-Brunt, Annabel
A1 - Evans, Matthew L.
A1 - Evans, Rob
A1 - Fairlamb, Ian
A1 - Franklin, Barnabas A.
A1 - Frey, Jeremy
A1 - Ganose, Alex M.
A1 - Goulding, Mark
A1 - Hafizi, Roohollah
A1 - Hakkennes, Matthijs
A1 - Hickey, Niamh
A1 - James, Gillian
A1 - Jelfs, Kim E.
A1 - Kalikadien, Adarsh V.
A1 - Kapil, Venkat
A1 - Koczor-Benda, Zsuzsanna
A1 - Krammer, Ferdinand
A1 - Kulik, Heather J.
A1 - Kumar, Vishank
A1 - Kuttner, Christian
A1 - Lam, Erwin
A1 - Lou, Yuchen
A1 - Mante, Eltjo
A1 - Martin, Jennie
A1 - Mroz, Austin M.
A1 - Nematiaram, Tahereh
A1 - Pare, Charles W. P.
A1 - Patra, Sarbani
A1 - Proudfoot, James
A1 - Ruscic, Branko
A1 - Ryder, Matthew R.
A1 - Sakaushi, Ken
A1 - Saßmannshausen, Jörg
A1 - Savoie, Brett M.
A1 - Schneider, Nadine
A1 - Schwaller, Philippe
A1 - Skjelstad, Bastian Bjerkem
A1 - Sun, Wenhao
A1 - Szczypiński, Filip T.
A1 - Torrisi, Steven
A1 - Ueltzen, Katharina
A1 - Vishnoi, Shubham
A1 - Walsh, Aron
A1 - Wang, Xinwei
A1 - Wilson, Chloe
A1 - Wu, Ruiqi
A1 - Zeitler, Jakob
T1 - Discovering structure–property correlations: General discussion
N2 - This article is a discussion of the paper "Web-BO: Towards increased accessibility of Bayesian optimisation (BO) for chemistry" by Austin M. Mroz, Piotr N. Toka, Ehecatl Antonio del Río Chanona and Kim E. Jelfs (Faraday discussions, 2025, 256, 221-234).
KW - Materials design
KW - Machine learning
KW - Automation
KW - Materials discovery
PY - 2025
DO - https://doi.org/10.1039/d4fd90062f
SN - 1359-6640
SN - 1364-5498
VL - 256
IS - Themed collection: Data-driven discovery in the chemical sciences
SP - 373
EP - 412
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-62208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-throughput Computational Screening With Chemical Heuristics, Workflows, and Machine Learning
N2 - Within my talk, I have introduced the audience to high-throughput materials discovery with the help of workflow tools, machine learning and chemical heuristics. I started with a general introduction to the Materials Project software infrastructure and databases such as the Materials Project and NOMAD. Then, I dived into machine learning tasks relying on chemical bonding information, machine-learned interatomic potentials, and experimental data. Target properties of the machine-learning tasks were thermal properties, phonons, magnetism and synthesizability.
T2 - Seminar at the Inorganic Chemistry Laboratory in Oxford
CY - Oxford, United Kingdom
DA - 25.09.2025
KW - High-throughput
KW - Sustainability
KW - Machine Learning
KW - Materials Design
KW - Thermal Conductivity
KW - Magnetism
KW - Synthesizability
KW - Materials Acceleration Platform
PY - 2025
AN - OPUS4-64217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
A1 - Bustamante, Joana
A1 - Mieller, Björn
A1 - Stawski, Tomasz
A1 - George, Janine
A1 - Knoop, F.
T1 - High-quality zirconium vanadate samples for negative thermal expansion (NTE) analysis
N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which exhibits significant isotropic contraction over a broad temperature range (~150°C < T < 800°C). The linear thermal expansion coefficient of ZrV2O7 is −7.1×10-6 K-. Therefore, it can be used to create composites with controllable expansion coefficients and prevent destruction by thermal shock.
Material characterization, leading to application, requires pure, homogenous samples of high crystallinity via a reliable synthesis route. While there is a selection of described syntheses in the literature, it still needs to be addressed which synthesis route leads to truly pure and homogenous samples. Here, we study the influence of the synthesis methods (solid-state, sol-gel, solvothermal) and their parameters on the sample's purity, crystallinity, and homogeneity. The reproducibility of results and data obtained with scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric analysis (DSC/TGA) were analyzed extensively. The sol-gel method proves superior to the solid-state method and produces higher-quality samples over varying parameters. Sample purity also plays an important role in NTE micro and macro-scale characterizations that explain the impact of porosity versus structural changes.
Moreover, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation, temperature-dependent effective harmonic potentials) in combination with experimental methods to follow and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder, microstructure, and defects. Khosrovani et al. and Korthuis et al., in a series of diffraction experiments, attributed the thermal contraction of ZrV2O7 to the transverse thermal motion of oxygen atoms in V-O-V linkages. In addition to previous explanations, we hypothesize that local disorder develops in ZrV2O7 crystals during heating.
We are working on the experimental ZrV2O7 development and discuss difficulties one might face in the process as well as high-quality sample significance in further investigation. The obtained samples are currently used in the ongoing research of structure analysis and the negative thermal expansion mechanism.
T2 - 16th International conference on materials chemistry (MC16)
CY - Dublin, Ireland
DA - 03.07.2023
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - TDEP
PY - 2023
AN - OPUS4-58134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Gook, S.
A1 - Rethmeier, Michael
T1 - KI zur Prozessüberwachung im Unterpulverschweißen
N2 - Beim Unterpulverschweißen sind die Prozessgeräusche ein Indikator für eine gute Fügequalität. Diese Beurteilung kann i.d.R. nur von einer erfahrenen Fachkraft durchgeführt werden. Eine kürzlich entwickelte künstliche Intelligenz kann automatisch das akustische Prozesssignal anhand vortrainierter Merkmale klassifizieren und die Fügequalität anhand des Geräuschs beurteilen. Der Algorithmus, einmal richtig trainiert, kann den Prüfaufwand beim Unterpulverschweißen deutlich reduzieren.
KW - Unterpulverschweißen
KW - Künstliche Intelligenz
KW - Prozessüberwachung
KW - Körperschall
PY - 2024
SP - 1
EP - 2
AN - OPUS4-59483
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zimmermann, Yoel
A1 - Bazgir, Adib
A1 - Al-Feghali, Alexander
A1 - Ansari, Mehrad
A1 - Bocarsly, Joshua
A1 - Brinson, L Catherine
A1 - Chiang, Yuan
A1 - Circi, Defne
A1 - Chiu, Min-Hsueh
A1 - Daelman, Nathan
A1 - Evans, Matthew
A1 - Gangan, Abhijeet S
A1 - George, Janine
A1 - Harb, Hassan
A1 - Khalighinejad, Ghazal
A1 - Takrim Khan, Sartaaj
A1 - Klawohn, Sascha
A1 - Lederbauer, Magdalena
A1 - Mahjoubi, Soroush
A1 - Mohr, Bernadette
A1 - Mohamad Moosavi, Seyed
A1 - Naik, Aakash Ashok
A1 - Ozhan, Aleyna Beste
A1 - Plessers, Dieter
A1 - Roy, Aritra
A1 - Schoeppach, Fabian
A1 - Schwaller, Philippe
A1 - Terboven, Carla
A1 - Ueltzen, Katharina
A1 - Wu, Yue
A1 - Zhu, Shang
A1 - Janssen, Jan
A1 - Li, Calvin
A1 - Foster, Ian
A1 - Blaiszik, Ben
T1 - 32 examples of LLM applications in materials science and chemistry: towards automation, assistants, agents, and accelerated scientific discovery
N2 - Large Language Models (LLMs) are reshaping many aspects of materials science and chemistry research, enabling advances in molecular property prediction, materials design, scientific automation, knowledge extraction, and more. Recent developments demonstrate that the latest class of models are able to integrate structured and unstructured data, assist in hypothesis generation, and streamline research workflows. To explore the frontier of LLM capabilities across the research lifecycle, we review applications of LLMs through 34 total projects developed during the second annual Large Language Model Hackathon for Applications in Materials Science and Chemistry, a global hybrid event. These projects spanned seven key research areas: (1) molecular and material property prediction, (2) molecular and material design, (3) automation and novel interfaces, (4) scientific communication and education, (5) research data management and automation, (6) hypothesis generation and evaluation, and (7) knowledge extraction and reasoning from the scientific literature. Collectively, these applications illustrate how LLMs serve as versatile predictive models, platforms for rapid prototyping of domain-specific tools, and much more. In particular, improvements in both open source and proprietary LLM performance through the addition of reasoning, additional training data, and new techniques have expanded effectiveness, particularly in low-data environments and interdisciplinary research. As LLMs continue to improve, their integration into scientific workflows presents both new opportunities and new challenges, requiring ongoing exploration, continued refinement, and further research to address reliability, interpretability, and reproducibility.
KW - Large Language Models
KW - Machine Learning
KW - Materials Design
KW - Bonding Analysis
KW - Phonons
KW - Thermal properties
PY - 2025
DO - https://doi.org/10.1088/2632-2153/ae011a
SN - 2632-2153
VL - 6
IS - 3
SP - 1
EP - 34
PB - IOP Publishing
AN - OPUS4-64019
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Anker, Andy S.
A1 - Aspuru-Guzik, Alán
A1 - Bechtel, Tim
A1 - Bigi, Filippo
A1 - Briling, Ksenia R.
A1 - Das, Basita
A1 - David, Nicholas
A1 - Day, Graeme M.
A1 - Deringer, Volker L.
A1 - Dyer, Matthew
A1 - Eardley-Brunt, Annabel
A1 - Evans, Matthew L.
A1 - Evans, Rob
A1 - Franklin, Barnabas A.
A1 - Ganose, Alex M.
A1 - George, Janine
A1 - Goulding, Mark
A1 - Hickey, Niamh
A1 - James, Gillian
A1 - Kalikadien, Adarsh V.
A1 - Kapil, Venkat
A1 - Kulik, Heather J.
A1 - Kumar, Vishank
A1 - Kuttner, Christian
A1 - Lam, Erwin
A1 - Lederbauer, Magdalena
A1 - Lou, Yuchen
A1 - Martin, Jennie
A1 - Marulanda Bran, Andres
A1 - Mathea, Miriam
A1 - Pickard, Chris J.
A1 - Ruscic, Branko
A1 - Ryder, Matthew R.
A1 - Sabanza Gil, Victor
A1 - Schwaller, Philippe
A1 - Segler, Marwin H. S.
A1 - Sun, Wenhao
A1 - Tanovic, Sara
A1 - Treyde, Wojtek
A1 - Walsh, Aron
A1 - Wu, Ruiqi
T1 - Discovering synthesis targets: General discussion
N2 - This article is a discussion of the paper "Analysis of uncertainty of neural fingerprint-based models" by Christian W. Feldmann, Jochen Sieg and Miriam Mathea (Faraday discussions, 2025, DOI: 10.1039/D4FD00095A).
KW - Automation
KW - Materials acceleration platforms
KW - Machine learning
KW - Materials design
KW - Materials discovery
KW - Density functional theory
KW - Ab initio
PY - 2025
DO - https://doi.org/10.1039/D4FD90064B
SN - 1359-6640
SN - 1364-5498
VL - 256
IS - Themed collection: Data-driven discovery in the chemical sciences
SP - 639
EP - 663
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-62317
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automated Bonding Analysis with LobSTER and ATOMATE2
N2 - The talk introduced automated bonding analysis with the programs LobsterPy and atomate2. I especially emphasized how bonding descriptors can be used for materials design.
T2 - Lobster Bonding Analysis School
CY - Berlin, Germany
DA - 11.06.2025
KW - Automation
KW - Bonding Analysis
KW - Materials Design
KW - High throughput
KW - Ab initio
KW - Thermal conductivity
PY - 2025
AN - OPUS4-63420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
T1 - Mathematical analysis of the bulging effect in high power laser beam welding of thick steel sheets
N2 - The present work is devoted to the mathematical analysis of the bulging effect in high-power laser beam welding of thick steel sheets. The numerical results are based upon experimental results from previous studies, revealing the relationships between the bulging effect, the hot cracking formation, and the distribution of alloying elements in the weld pool. The widening of the molten pool in its middle area is observed for both complete and partial penetration welding of 8 mm - 15 mm thick structural steel sheets. The weld pool shape is extracted from the simulations to evaluate the extent of the necking and bulging of the solidification isotherm and their influence on the hot cracking formation and the mixing behavior of the weld pool. Relying on an earlier numerical study utilizing a fixed keyhole, simulation models considering a dynamic keyhole are developed thereto. The link between the bulge and the studied phenomena is found to be significant.
T2 - Beam Technologies & Laser Applications
CY - Saint Petersburg, Russia
DA - 20.09.2021
KW - Deep penetration laser beam welding
KW - Bulge effect
KW - Numerical modelling
KW - Hot cracking
KW - Necking
KW - Mixing behavior
PY - 2021
AN - OPUS4-53375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ueltzen, Katharina
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Benner, Philipp
A1 - George, Janine
T1 - Software and data repository: Can simple exchange heuristics guide us in predicting magnetic properties of solids?
N2 - Software and data for the publication "Can simple exchange heuristics guide us in predicting magnetic properties of solids?" Release that corresponds to the first preprint version of the article. Full Changelog: https://github.com/DigiMatChem/paper-exchange-heuristics-in-magnetic-materials/commits/v1.0.0
KW - Magnetism
KW - Machine Learning
KW - Materials Design
KW - Chemically Complex Materials
KW - Sustainable Materials Design
PY - 2025
DO - https://doi.org/10.5281/zenodo.16811104
PB - Zenodo
CY - Geneva
AN - OPUS4-64672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - Towards arc welding reference data: Open Science laboratories at BAM
N2 - As industries move for ever faster development and adoption cycles of emerging new technologies in the field of welding, the meticulous and longer-winded approach of the scientific research process can feel harder to integrate. To help bridge this gap and increase the speed, quality, and adoption rate of publicly funded research, the Bundesanstalt für Materialforschung und -prüfung (BAM) continues to work towards enabling scientists with direct access to necessary software tools and - in the future – highest quality welding research reference data to further foster collaborations.
On the experimental side, the arc welding group at BAM division 9.3 “welding technologies” is continuing to expand and upgrade its capacities of robotic welding systems with integrated state of the art sensor technologies and software solutions. This allows all experiments to be recorded and measured in micro-millimeter accuracy and at sub-millisecond precision, including welding process data, complete spatial geometry and temperature measurements, process video recordings and more. The custom software-based solutions and interfaces allow scaling of the welding systems from large thick plate offshore applications to small additive repair weldments in wind turbine blades to multi-hour continuous weldments in additive manufacturing applications. In addition to the data gathered during the welding process itself, the relevant testing results and materials properties produced at BAM or externally can be integrated seamlessly. This allows detailed traceability of all results back to the actual welding process.
Regardless of the scope and application, complete datasets can be made accessible for research or industry partners in the highest resolution based on the open source WelDX (welding data exchange) file format.
Figure 1. Welding experiment representation including dynamic process data, cross-section imaging and hardness measurements from a single weldx file.
The talk will give an overview of the experimental facilities and workflows as well as current software developments with a focus on research data quality assurance, traceability, and accessibility.
Based on the integration into latest research trends and activities of the “welding technologies” division, the path to publishing reference datasets for arc welding process for various applications and materials is outlined and discussed.
T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024
CY - Berlin, Germany
DA - 12.06.2024
KW - Additive Manufacturing
KW - Arc welding
KW - DED-arc
KW - Research data
KW - Reference data
PY - 2024
AN - OPUS4-60249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
T1 - Experimental and analytical investigation of high temperature fatigue crack growth at notches in a polycrystalline Nickel base superalloy
N2 - The scatter of fatigue crack growth data can become significant for coarse grained materials. By using a probabilistic description of crack propagation as the foundation of a lifetime prediction model, lifetime scatter of laboratory specimens can be reproduced. However, the lifetime of real components is subjected to additional scattering factors such as surface condition or uncertainty regarding direction and shape of emerging cracks. These factors need to be addressed in order to exploit the advantages of probabilistic description, i.e. the reduction of unnecessary conservatisms.
High temperature LCF (Low-Cycle-Fatigue) tests were performed with center hole specimens of a coarse-grained Nickel base Superalloy. In addition, crack propagation tests with Double Edge Notch specimens were performed. A procedure to detect the shape of the starting crack that combines the potential drop method and induction thermography was developed. The geometry and the number of notches were varied. Moreover, specimen with different hole surface finishes were investigated, which showed a detrimental effect of the roughness of the hole surface.
The results have been compared to predictions of a probabilistic tool for the estimation of lcf lifetime that has been calibrated beforehand on laboratory specimens with and without notches. In parallel, a fracture mechanics-based lifetime model was developed, which includes the initial crack size as a critical parameter. Thereby, the influence of the large grain size (>1mm), and the shape of the starting crack at the notch were considered.
Acknowledgements
The investigations are conducted as part of the joint research program COOREFLEX-Turbo in the frame of AG Turbo. The work is supported by Siemens AG and the Bundesministerium für Wirtschaft und Technologie (BMWi) as per resolution of the German Federal Parliament under grant number 03ET7071E.
T2 - Low Cycle Fatigue 9
CY - Berlin, Germany
DA - 21.06.2022
KW - Nickel-base superalloys
KW - Notches
KW - LCF
PY - 2022
AN - OPUS4-55335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
T1 - Experimental and analytical investigation of Low Cycle Fatigue Damage at notches in a polycrystalline Nickel base superalloy
N2 - Turbine blades often contain cylindric holes used to generate an air film that protects the blade alloy from the hot gases. These cooling holes of diameter around one mm are drilled by laser through the thickness of the blades. Unfortunately, the resulting stress concentration and the drilling-induced damage are known to favor crack initiation from the holes. It is thus necessary to assess the impact of these cooling holes on the structural integrity of the blades. Since cracks initiate very readily, the fatigue life of the components is mainly controlled by the propagation of the cracks in the stress gradient induced by the holes.
For this purpose, displacement controlled high-temperature LCF (Low-Cycle-Fatigue) tests were performed with center hole specimens of a coarse-grained Nickel base Superalloy. The tests were stopped after a defined load drop. In addition, crack propagation tests with Double Edge Notch specimens were performed. Moreover, specimens with different hole surface finishes were investigated, which showed a detrimental effect of the hole surface roughness. In parallel, an evaluation of the LCF tests based on a fracture mechanics-based model (Madia et al., Eng. Fract. Mech., 2018) has been applied. Thereby, the specimen life is controlled by the crack propagation time until failure. Crack growth is controlled by a modified NASGRO equation accounting for large-scale yielding and a progressive build-up of crack closure. The initial crack size has been derived from the measurements of defects around the borehole. A reasonable agreement between predicted and measured lifetimes is observed if one keeps in mind the large uncertainty regarding the effective shape of the cracks.
T2 - 23rd European Conference on Fracture
CY - Funchal, Madeira, Portugal
DA - 27.06.2022
KW - Nickel-base superalloys
KW - Notches
KW - LCF
PY - 2022
AN - OPUS4-55338
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brunner-Schwer, C.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Entwicklung des hybriden Auftragschweißens als leistungsfähigen Bechichtungsprozess für Korrosions- und Verschleißschutzschichten
N2 - Dieser Beitrag stellt Ergebnisse der Untersuchungen zum Auftragschweißen als Plasma-Laserstrahl-Hybrid-Prozess dar. Es hat sich gezeigt, dass ein Laserstrahl, der in einer gemeinsamen Prozesszone mit einem Plasma-Pulver-Auftragschweißprozess vorlaufend angeordnet ist, diesem Prozess eine erhebliche Geschwindigkeitssteigerung sowie eine Verbesserung der Stabilität ermöglicht. Der Hybrid-Prozess konnte mit Verschleißschutzwerkstoffen
sowie dem Korrosionsschutzwerkstoff Inconel 625 bei Vorschubgeschwindigkeiten von bis zu 10 m/min erfolgreich validiert werden.
Im Hinblick auf die aktuellen Entwicklungen zu Hochgeschwindiglceits-Laserstrahlauftragschweißen kann der Plasma-Laserstrahl-Hybrid-Prozess
zwischen diesen und den konventionellen Verfahren eingeordnet werden.
KW - Auftragschweißen
KW - Hybridschweißen
KW - Laserstrahlschweißen
KW - Schutzgasschweißen
PY - 2020
SN - 0036-7184
VL - 72
IS - 8
SP - 474
EP - 475
AN - OPUS4-51321
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Improvement of Charpy impact toughness by using an AC magnet backing system at laser hybrid welding of thick S690QL steels
N2 - The study deals with the influence of the heat input and the resulting cooling times on the microstructure and Charpy impact toughness of single-pass laser hybrid welded 20-mm thick high-strength steel S690QL. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured in-situ using a pyrometer and an optical fibre in three different depths of the seam where Charpy impact test specimens were also later taken. Thereby, three different heat inputs from 1.3 kJ/mm to 2 kJ/mm were investigated. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required impact toughness of 38 J/cm2 could be reached in dependance on applied heat input, especially at the heat input of 1.6 kJ/mm.
T2 - LANE 2022: 12th CIRP Conference on Photonic Technologies
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser hybrid welding
KW - Electromagnetic backing
KW - Charpy impact toughness
KW - Thick-plate welding
KW - Thermal cycles
PY - 2022
AN - OPUS4-56369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Jonathan
T1 - High-resolution in-situ image analysis in laser powder bed fusion
N2 - Visual images captured - in-situ - in laser powder bed fusion (PBF-LB/M) provide valuable insights into process dynamics. This poster presents methods for analyzing high-resolution images with a spatial resolution of 17 µm/pixel and a size of 9344 × 7000 pixels. In the context of identifying microstructural anomalies, the relationship between the contrast values derived from the grey-level co-occurrence matrix (GLCM) of post-exposure images and ex situ measurements of surface roughness, porosity, and melt pool depth is illustrated. Furthermore, a workflow to detect process anomalies in post recoating images using an edge device is presented.
T2 - BAM Advisory Council Meeting
CY - Berlin, Germany
DA - 25.06.2025
KW - Additive manufacturing
KW - High resolution camera
KW - Image processing
KW - In situ monitoring
KW - Powder bed fusion
PY - 2025
AN - OPUS4-63990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Bayerlein, Bernd
A1 - Chen, Yue
A1 - Olbricht, Jürgen
A1 - Skrotzki, Birgit
A1 - von Hartrott, P.
A1 - Portella, Pedro Dolabella
A1 - Waitelonis, J.
A1 - Birkholz, H.
A1 - Grundmann, J.
ED - Zimmermann, M.
T1 - Zugversuchsdaten FAIR integriert: Von einer normenkonformen Ontologie bis zu interoperablen Daten im Triple Store
N2 - Das hochaktuelle Thema der Integration und Wiederverwendung von Wissen und Daten aus Herstellung, Bearbeitung und Charakterisierung von Materialien ('Digitalisierung von Materialien') wird in den Projekten Innovationsplattform MaterialDigital (PMD, materialdigital.de) und Materials-open-Lab (Mat-o-Lab, matolab.org) adressiert. In diesem Beitrag werden die Weiterentwicklungen in diesen Projekten hinsichtlich der Speicherung von Zugversuchsdaten gemäß einer normenkonformen (DIN EN ISO 6892-1:2019-11) ontologischen Repräsentation vorgestellt. Das umfasst den Weg von der Entwicklung einer Ontologie nach Norm, der Konvertierung von Daten aus Standardtests in das interoperable RDF-Format bis hin zur Verknüpfung von Ontologie und Daten. Letztendlich können die entsprechenden Daten in einem Triple Store abgelegt und abgefragt werden.
T2 - Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Ontology
KW - Semantic Web
KW - Digitalization
KW - Knowledge Representation
KW - Tensile Test
PY - 2022
UR - https://dgm.de/fileadmin/DGM/Veranstaltungen/2022/Werkstoffpruefung/Tagungsband/WP2022-Tagungsband-online.pdf
SN - 978-3-88355-430-3
SP - 105
EP - 110
PB - DGM - Deutsche Gesellschaft für Materialkunde e.V
CY - Sankt Augustin
AN - OPUS4-56836
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
T1 - Assessment of keyhole stability in laser beam welding with external magnetic field using numerical simulation
N2 - The challenge of understanding the physical mechanisms behind porosity reduction by a magnetic field during laser beam welding (LBW) is partly due to the difficulty in quantitatively evaluating keyhole stability. The commonly used index, such as keyhole depth, is typically one-dimensional, which is insufficient to capture the dynamic and three-dimensional fluctuations of the keyhole. In this paper, by utilizing a 3D multiphysical model of LBW with magnetic field, a novel keyhole geometry reconstruction algorithm has been developed to describe the keyhole profile and its fluctuation in a statistical manner to evaluate keyhole stability quantitatively. An equivalent diameter is proposed in this algorithm to reduce the irregularity of the keyhole geometry. The calculation results indicate that the time-averaged keyhole shape over 300 ms in the LBW of steel is conical, regardless of the application of an external magnetic field, which provides a more representative shape. Meanwhile, it is observed from the statistical aspect that the keyhole diameter becomes smaller, except the top part, under the influence of the magnetic field. The standard deviation of the equivalent diameter can be used as a physical variable to assess the keyhole stability quantitatively. The application of an external magnetic field can produce a noticeable reduction of the standard deviation of the equivalent diameter, namely, stabilizing the keyhole during LBW of steel. However, the different contribution from the keyhole stability affected by a magnetic field in suppressing porosity is different with materials.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 04.11.2024
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Keyhole shape
KW - Keyhole stability
KW - Magnetic field
PY - 2024
AN - OPUS4-61600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Strain distribution vs strain evolution during solidification cracking CTW test for laser beam welding of 1 mm austenitic stainless steels
N2 - Laser welding is a widely established manufacturing process across many industrial sectors. However, solidification cracking and the weldability of materials have remained contentious issues for many years, particularly concerning the causes of hot crack formation.
The local distribution of total strain was measured in close proximity to the solidification zone during laser welding of AISI 304 and AISI 310S stainless steels, using the Controlled Tensile Weldability (CTW) test. In this setup, 1 mm thick weld coupons were subjected to a defined external tensile load during welding. Mechanical loading parameters were varied by adjusting the strain rate and ultimate strain level to identify the critical conditions that lead to solidification crack formation along the weld seam centerline. Using Digital Image Correlation (DIC) and the optical flow method [1], we estimated the local strain distribution at the surface near the molten pool and tracked its evolution across several characteristic zones—before, during, and after the application of mechanical loading. The results revealed that solidification crack formation coincides with regions of high plastic deformation within a critical temperature range. Furthermore, we identified a clear relationship between strain rate and both crack initiation probability and maximum local strain. Importantly, neither strain rate nor maximum strain alone is sufficient to predict cracking; instead, their combined effect must be considered to accurately assess hot cracking susceptibility.
T2 - AJP 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Laser beam welding
KW - Solidification cracking
KW - Optical measurement
PY - 2025
AN - OPUS4-64431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ueltzen, Katharina
T1 - Can simple exchange heuristics help us in predicting magnetic properties of solids?
N2 - Environmental and scarcity issues of common functional magnetic materials for, e.g., permanent magnets have intensified the search for rare-earth-free alternatives. This challenge is increasingly met by machine learning of magnetic properties of transition-metal compounds. Surprisingly, bond-angle-derived features were not found to be relevant for magnetic structure prediction in previous studies using DFT-computed labels. This contrasts with the Kanamori-Goodenough-Anderson (KGA) rules of superexchange, present in every magnetism textbook.
These semiempirical rules predict whether a nearest-neighbor magnetic interaction in insulators is FM or AFM based on the bond angle, orbital symmetry, and orbital occupancy. For some cases, the rules can be simplified further to only consider the bond angle of neighboring magnetic sites (KGA rules of thumb).
We review magnetism—bond angle trends within the MAGNDATA database, the largest collection of experimentally determined magnetic structures. Observed trends follow the KGA rules of thumb, and exceptions can be rationalized. In contrast, bond angles in a popular theoretical DFT database show very different trends and do not depend on the magnetic ordering.
Building on our analysis, we engineer heuristic-derived features for the machine learning of magnetic structures. We introduce a new, informative label for predicting magnetic structures that can be extended to magnetic sites and structures of arbitrary complexity. We show that features derived from the heuristic are of high importance for this machine learning task. Beyond this, our model enables the prediction of non-collinear magnetic structures.
T2 - AI MSE 2025
CY - Bochum, Germany
DA - 18.11.2025
KW - Magnetism
KW - Machine Learning
KW - Materials Design
KW - Chemically Complex Materials
PY - 2025
AN - OPUS4-64799
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-throughput Computational Screening
N2 - I provided a tutorial lecture on high-throughput DFT calculations in combination with heuristics, machine learning and workflows. I started with the introduction of the software infrastructure. Then, I showed applications for phonon predictions, magnetism and synthesizability prediction.
T2 - Machine Learning for Materials 2025
CY - Karlsruhe, Germany
DA - 08.09.2025
KW - Materials Design
KW - Automation
KW - High-throughput
KW - Magnetism
KW - Thermal conductivity
PY - 2025
AN - OPUS4-64074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Introduction to computational methods with periodic boundaries
N2 - I provided an introduction to density functional theory (DFT) with periodic boundary conditions. I repeated the derivation of DFT and the Bloch theorem. Then, I combined both concepts. Additionally, I delivered an outlook to automatic DFT for solids and machine learning in the field.
T2 - Computational Methods in Crystallography
CY - Lausanne, Switzerland
DA - 09.09.2025
KW - DFT
KW - Automation
KW - Machine Learning
KW - Bloch Theorem
KW - Materials Design
PY - 2025
AN - OPUS4-64044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Von der Computerchemie zur Materialinformatik
N2 - In dem Vortrag stelle ich meinen Lebenslauf von einem Chemiestudium bis hin zur Materialinformatik vor. Hierbei stelle ich unter anderem Computerchemie und Materialinformatik vor. Das beinhaltet Kurzeinführungen in die Quantenmechanik und das maschinelle Lernen.
T2 - Landesseminar Berlin Brandenburg der deutschen Auswahl für die Internationale Chemieolympiade (Schülerwettbewerb)
CY - Berlin, Germany
DA - 17.10.2025
KW - Materials Design
KW - Computational Chemistry
KW - Materials Acceleration Platforms
KW - Automation
KW - Machine Learning Potentials
KW - Outreach
PY - 2025
AN - OPUS4-64412
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Advancing Industrial Mechanochemistry: Real-Time Insights for Sustainable, Solvent-Free Manufacturing
N2 - Mechanochemistry is an environmentally friendly synthetic approach that enables the sustainable production of a wide range of chemicals while reducing or eliminating the need for solvents. Reactive extrusion aims to move mechanochemistry from its conventional gram-scale batch reactions, typically performed in laboratory ball mills, to a continuous, large-scale process. Meeting this challenge requires in situ monitoring techniques to gain insights into reactive extrusion and its underlying processes. While the effectiveness of in situ Raman spectroscopy in providing molecular-level information has been demonstrated, our study uses energy-dispersive X-ray diffraction to monitor reactive extrusion in real time at the crystalline level. Our results provide previously unavailable control over thereactiveextrusion process, promoting its perception as an industrially feasible green alternative to traditional solventbased syntheses.
T2 - #RSCPoster 2025
CY - Online meeting
DA - 04.03.2025
KW - Mechanochemistry
PY - 2025
AN - OPUS4-63803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Bähring, S.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Transferability of ANN-generated parameter sets from welding tracks to 3D-geometries in Directed Energy Deposition
N2 - Directed energy deposition (DED) has been in industrial use as a coating process for many years. Modern applications include the repair of existing components and additive manufacturing. The main advantages of DED are high deposition rates and low energy input. However, the process is influenced by a variety of parameters affecting the component quality. Artificial neural networks (ANNs) offer the possibility of mapping complex processes such as DED. They can serve as a tool for predicting optimal process parameters and quality characteristics. Previous research only refers to weld beads: a transferability to additively manufactured three-dimensional components has not been investigated. In the context of this work, an ANN is generated based on 86 weld beads. Quality categories (poor, medium, and good) are chosen as target variables to combine several quality features. The applicability of this categorization compared to conventional characteristics is discussed in detail. The ANN predicts the quality category of weld beads with an average accuracy of 81.5%. Two randomly generated parameter sets predicted as “good” by the network are then used to build tracks, coatings,walls, and cubes. It is shown that ANN trained with weld beads are suitable for complex parameter predictions in a limited way.
KW - Welding parameter
KW - Quality assurance
KW - DED
KW - Artificial neural network
KW - Additive manufacturing
PY - 2022
DO - https://doi.org/10.1515/mt-2022-0054
SN - 0025-5300
VL - 64
IS - 11
SP - 1586
EP - 1596
PB - De Gruyter
AN - OPUS4-56278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, Sergej
A1 - El-sari, Bassel
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Application of AI-based welding process monitoring for quality control in pipe production
N2 - The paper presents the experimental results into the development of a multi-channel system for monitoring and quality assurance of the multi-wire submerged arc welding (SAW) process for the manufacture of large diameter pipes. Process signals such as welding current, arc voltage and the acoustic signal emitted from the weld zone are recorded and processed to provide information on the stability of the welding process. It was shown by the experiments that the acoustic pattern of the SAW process in a frequency range between 30 Hz and 2.5 kHz contains the most diagnostic information. The on-line quality assessment of the weld seam produced is carried out in combination with methods of artificial intelligence (AI). From the results obtained, it can be concluded that the use of the latest concepts in welding and automation technology, combined with the high potential of AI, can achieve a new level of quality assurance in pipe manufacturing.
KW - Submerged arc welding
KW - Artificial intelligence
KW - High-strength fine-grain steels
KW - Quality control
PY - 2024
DO - https://doi.org/10.37434/tpwj2024.06.01
SN - 0957-798X
IS - 6
SP - 3
EP - 8
PB - The Paton Publishing House
AN - OPUS4-61000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, M.
A1 - Wang, J.
A1 - Kaiser, L.
A1 - Rethmeier, Michael
T1 - Automated Tool-Path Generation for Rapid Manufacturing of Additive Manufacturing Directed Energy Deposition Geometries
N2 - In additive manufacturing (AM) directed energy deposition (DED), parts are built by welding layers of powder or wire feedstock onto a substrate with applications for steel powders in the fields of forging tools, spare parts, and structural components for various industries. For large and bulky parts, the choice of toolpaths influences the build rate, the mechanical performance, and the distortions in a highly geometry-dependent manner. With weld-path lengths in the range of hundreds of meters, a reliable, automated tool-path generation is essential for the usability of DED processes. This contribution presents automated tool-path generation approaches and discusses the results for arbitrary geometries. Socalled “zig-zag” and “contour-parallel” processing strategies are investigated and the tool-paths are automatically formatted into machine-readable g-code for experimental validation to build sample geometries. The results are discussed in regard to volume-fill, microstructure, and porosity in dependence of the path planning according to photographs and metallographic cross-sections.
KW - Porosity
KW - Path planning
KW - Mechanical properties
KW - Laser metal deposition
KW - Additive manufacturing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510454
DO - https://doi.org/10.1002/srin.202000017
VL - 91
IS - 11
SP - 2000017
PB - WILEY-VCH Verlag GmbH & co. KGaA
CY - Weinheim
AN - OPUS4-51045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Batahgy, A.
A1 - Saiyah, A.
A1 - Khafagi, S.
A1 - Gumenyuk, Andrey
A1 - Gook, Sergej
A1 - Rethmeier, Michael
T1 - Shielded metal arc welding of 9%Ni steel using matching ferritic filler metal
N2 - Motivated by the tensile strength loss of 9%Ni steel arc welded joints made using Ni-based austenitic filler metals, the feasibility of maintaining the tensile strength using matching ferritic filler metal has been demonstrated. In comparison with shielded metal arc welded joint made using Ni-based austenitic electrode ENiCrMo-6, higher tensile strength comparable to that of the base metal was obtained using matching ferritic electrode. Besides, sufficient impact toughness energies with much lower mismatch were obtained for weld metal and heat-affected zone.
Welded joint with a lower mechanical mismatching is of considerable importance for achieving acceptable combination of tensile strength and impact toughness. A better combination of These mechanical properties is ensured by applying a post weld heat treatment.
KW - 9%Ni steel
KW - Ni-based austenitic welding electrode
KW - Matching ferritic welding electrode
KW - Mechanical properties
KW - Mechanical mismatching
KW - Microstructure
KW - SMAW
PY - 2020
DO - https://doi.org/10.1080/13621718.2020.1846936
VL - 26
IS - 2
SP - 116
EP - 122
PB - Taylor & Francis
AN - OPUS4-52025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, Sergej
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Method for defect-free hybrid laser-arc welding of closed circumferential welds
N2 - This paper presents investigation results of a process for defect-free hybrid laser arc welding (HLAW) of closed circumferential welds. The process aims to avoid weld imperfections in the overlap area of a HLAW circumferential weld. A process control strategy for closing the circumferential weld was developed to achieve a defect-free overlap region by controlling the solidification conditions at the end of the weld. The controlled heat flow is achieved by adjusting the parameters of both welding processes involved, the laser beam as well as gas metal arc welding (GMAW) process. Experimental investigations were carried out on 12 mm to 15 mm thick tube sections. The influence of process parameters such as the laser ramp time, the change in magnification scale and the defocusing of the laser beam on the solidifi-cation conditions at the end of the circumferential weld was investigated to find an optimum strategy for ramping out the process energy. Within the framework of the experimental studies, it was demonstrated that defocusing the laser beam in the range between 60 mm and 100 mm over a short run-out area of the weld of approximately 15 mm led to a significantly better weld formation in the overlap area. A favourable cup-shaped weld shape could be achieved without a tendency to crack. The laser optics with a motor-driven lens system made it possible to increase the laser beam diameter without changing the position of the GMAW arc relative to the component surface.
KW - Weld defects
KW - Hybrid welding
KW - Laser beam welding
KW - Pipe manufacturing
KW - Gas shielded arc welding
PY - 2021
VL - 20
IS - 4
SP - 334
EP - 339
PB - DVS Media
AN - OPUS4-54665
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
A1 - Gook, Sergej
T1 - Verfahren zum fehlerfreien Laserstrahl-Hybridschweißen von geschlossenen Rundnähten
N2 - In diesem Beitrag werden Ergebnisse der Untersuchungen eines Verfahrens zum fehlerfreien Laserstrahl-Hybridschweißen von geschlossenen Rundnähten vorgestellt. Das Verfahren zielt auf die Vermeidung von Schweißimperfektionen im Überlappbereich einer laserstrahlhybridgeschweißten Rundnaht. Eine Strategie der Prozessführung beim Schließen der Rundnaht wurde entwickelt, mit der ein fehlerfreier Überlappbereich durch die Kontrolle der Erstarrungsbedingungen am Schweißnahtende erreicht wird. Die kontrollierte Wärmeführung wird durch eine Anpassung der Parameter von beiden beteiligten Schweißprozessen, dem Laserstrahl- sowie MSG-Schweißprozess realisiert. Experimentelle Untersuchungen wurden an 12 mm bis 15 mm dicken Rohrabschnitten durchgeführt. Der Einfluss von Prozessparametern wie der Laserleistungsrampe und Rampenzeit, der Veränderung des Abbildungsmaßstabes und der Defokussierung des Laserstrahls auf die Erstarrungsbedingungen am Ende der Rundnaht wurde untersucht, um eine optimale Strategie zum Herausführen der Prozessenergie zu finden. Im Rahmen der experimentellen Untersuchungen konnte gezeigt werden, dass eine Defokussierung des Laserstrahls im Bereich zwischen 60 mm und 100 mm über einen kurzen Auslaufbereich der Naht von ca. 15 mm zu einer deutlich besseren Nahtausbildung im Überlappbereich führte. Es konnte eine günstige kelchförmige Schweißnahtform ohne eine Tendenz zur Rissbildung erzielt werden. Die Laseroptik mit motorisch angesteuertem Linsensystem ermöglichte dabei eine Vergrößerung des Laserstrahldurchmessers ohne eine Veränderung der Position des MSG-Lichtbogens relativ zur Bauteiloberfläche.
T2 - DVS CONGRESS 2020
CY - Online meeting
DA - 14.09.2020
KW - Endkrater
KW - Rundnaht
KW - Laserhybridschweißen
PY - 2020
AN - OPUS4-51749
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
A1 - Gook, Sergej
T1 - Notch impact toughness of laser beam welded thick sheets of cryogenic nickel alloyed steel X8Ni9
N2 - This research work deals with the investigations of the impact toughness of laser beam welded 14.5 mm thick sheets made of cryogenic steel X8Ni9 as a function of preheating. This 9% nickel alloyed steel is widely used in the liquefied natural gas (LNG) industry. An application of highly efficient welding processes such as high-power laser beam welding (LBW) in LNG sector requires an understanding of the interactions between the LBW process parameters and weld properties, in particular the impact toughness. The results show that the original fine-grained martensitic microstructure of the base metal (BM) is significantly changed by melting and crystallization during the LBW, what can lead to a decrease in the impact toughness of the weld metal (WM) below the required level. An optimal preheating temperature range leads to the favorable thermal welding cycle and is of remarkable importance for maintaining the notch impact toughness of laser beam welded joints of these thick steel sheets. A parameter window was identified in which V-notch impact toughness comparable to that of the BM at -196 °C was achieved.
T2 - 11th CIRP Conference on Photonic Technologies LANE 2020
CY - Online meeting
DA - 06.09.2020
KW - Cryogenic steel
KW - Laser beam welding
KW - Welding thermal cycle
PY - 2020
AN - OPUS4-51750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - Influence of residual stress and microstructure on mechanical performance of LPBF TI-6AL-4V
N2 - Ti-6Al-4V alloy is intensively used in the aerospace industry because of its high specific strength. However, the application of Laser Powder Bed Fusion (LPBF) Ti-6Al-4V alloy for structurally critical load-bearing components is limited. One of the main limiting factors affecting the structural integrity, are manufacturing defects. Additionally, the high cooling rates associated with LPBF process result in the formation of large residual stress (RS) with complex fields. Such RS can cause cracking and geometrical distortions of the part even right after production. Also, the microstructure of LPBF Ti-6Al-4V in the as-built condition is significantly different from that of the conventionally produced alloy. All these factors affect the mechanical behavior of the material. Therefore, to improve the material performance it is important to evaluate the individual effect of RS, defects, and microstructure on fatigue life. To this aim Ti-6Al-4V LPBF material in as-built condition and subjected to different post-processing, including two heat treatments (for stress relief and microstructural modification) and Hot Isostatic Pressing (HIP, for densification), were investigated.
Prior to Low Cycle Fatigue (LCF) tests at operating temperature (300°C), the microstructure (phases, crystallographic texture, and grain morphology), the mesostructure (defect shape and distribution), and subsurface RS on the LCF samples were investigated. It was found that the fatigue performance of HIPped samples is similar to that of conventionally produced Ti-6Al-4V. The tensile RS found at the surface of as-built samples decreased the fatigue life compared to heat-treated samples. Additionally, the modification of the microstructure (by heat treatment) did not affect the fatigue performance in the regime of mostly elastic strain. This shows that in the absence of tensile RS the manufacturing defects solely control the failure of LPBF components and densification has the strongest effect on the improvement of the mechanical performance.
T2 - ASTM ICAM 2020
CY - Online meeting
DA - 16.11.2020
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Computed tomography
KW - Residual stress
PY - 2020
AN - OPUS4-51695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
T1 - The bulging effect and its relevance in high power laser beam welding
N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and two thermal imaging cameras is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs above 10 mm penetration depth. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.
T2 - 1st Annual Assembly and Conference of The Welding Federation of Africa (TWF-Africa)
CY - Cairo, Egypt
DA - 14.03.2023
KW - Laser beam welding
KW - Melt pool dinamics
PY - 2023
AN - OPUS4-58695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fu, B.
A1 - Shen, J.
A1 - Suhuddin, U.
A1 - Pereira, A.
A1 - Maawad, E.
A1 - dos Santos, J.
A1 - Klusemann, B.
A1 - Rethmeier, Michael
T1 - Revealing joining mechanism in refill friction stir spot welding of AZ31 magnesium alloy to galvanized DP600 steel
N2 - The application of magnesium (Mg) inevitably involves dissimilar welding with steel. A novel solid state spot welding method, refill friction stir spot welding (refill FSSW), was utilized to weld AZ31 Mg alloy to galvanized DP600 steel. Although Mg/Fe is an immiscible alloy system, defect-free welds with high strength were successfully obtained in a wide parameter window. The results of microstructure, interfacial reactions, and mechanical properties are reported to reveal the underlying joining mechanism. Due to the melting of Zn coating and subsequent Mg-Zn reactions, Mg-Zn eutectic and intermetallic compounds were detected within welds. Heterogeneous interfacial reactions occur along Mg/steel interface, and the relationship between interfacial structure and fracture behavior was investigated. The joining mechanism is associated with Zn coating and Fe-Al layer: 1) the presence of Zn coating is beneficial for achieving high-quality welding between Mg and steel, it protects the interface from oxidation and contributes to brazing of the weld; 2) the Al present in Mg alloy reacts with Fe, resulting in the growth of Fe-Al layer, which contributes to the diffusion bonding in the interface. The overall results clearly show that Refill FSSW is a competitive welding method for joining Mg and galvanized steel.
KW - Refill friction stir spot welding
KW - Multi-materials joining
KW - Magnesium alloy
KW - Galvanized steel
KW - Mechanical properties
KW - Microstructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536878
DO - https://doi.org/10.1016/j.matdes.2021.109997
SN - 0264-1275
VL - 209
SP - 109997
PB - Elsevier Ltd.
AN - OPUS4-53687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Churiaque, C.
A1 - Sanchez-Amaya, J.M.
A1 - Üstündag, Ömer
A1 - Porrua-Lara, M.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Improvements of hybrid laser arc welding for shipbuilding T-joints with 2F position of 8 mm thick steel
N2 - the joints throughout the structure. The flat units are constituted by butt welded flat plates, on which longitudinal T-welded reinforcements are placed to rigidize the structure. Among the different welding technologies, Hybrid Laser Arc Welding (HLAW) is becoming a mature process, profitable and highly productive. In addition, more innovative welding equipment are being developed nowadays, offering greater work flexibility, and raising expectations of achieving better quality, and economic viability. Another key point of HLAW to keep in mind is that structural distortions are reduced, resulting in decreasing the cost and time of straightening work.
In the present contribution, the influence of HLAW parameters on the quality of fillet joints of naval steel has been analysed. Experimental HLAW tests were performed with a high power disk laser to join EH36 naval steel plates, with a T configuration. The influence of different processing parameters has been analysed, as the laser power, welding speed, wire feed rate and the configuration of the HLAW processes (including head angle and laser/arc leading process). In addition, FEM simulations were carried out in order to estimate residual stresses and distortion of welded part. The distortion values provided by FEM presented excellent agreement with the measured experimental results. To evaluate the welds, non destructive tests including X-ray tests, metallographic analysis of cross sections, and microhardness mapping tests were performed.
Full penetration 8 mm T welds were obtained for the first time at an industrially applicable 2F position with a reasonable HLAW head angle, in one single step without sealing root, and using zero gap square groove Edge preparation. The present contribution presents welding rates up to 2.2 m/min for 2F T-joints of this steel thickness, a much higher processing velocity than previously reported for industrial applications.
KW - Hybrid laser arc welding
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528410
DO - https://doi.org/10.1016/j.optlastec.2021.107284
VL - 143
SP - 1
EP - 20
PB - Elsevier Ltd.
AN - OPUS4-52841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical analysis of the partial penetration high power laser beam welding of thick sheets at high process speeds
N2 - The present work is devoted to the numerical analysis of the high-power laser beam welding of thick sheets at different welding speeds. A three-dimensional transient multi-physics numerical model is developed, allowing for the prediction of the keyhole geometry and the final penetration depth. Two ray tracing algorithms are implemented and compared, namely a standard ray tracing approach and an approach using a virtual mesh refinement for a more accurate calculation of the reflection points. Both algorithms are found to provide sufficient accuracy for the prediction of the keyhole depth during laser beam welding with process speeds of up to 1.5 m/min. However, with the standard algorithm, the penetration depth is underestimated by the model for a process speed of 2.5 m/min due to a trapping effect of the laser energy in the top region. In contrast, the virtually refined ray tracing approach results in high accuracy results for process speeds of both 1.5 m/min and 2.5 m/min. A detailed study on the trapping effect is provided, accompanied by a benchmark including a predefined keyhole geometry with typical characteristics for the high-power laser beam welding of thick plates at high process speed, such as deep keyhole, inclined front keyhole wall, and a hump.
KW - High-power laser beam welding
KW - High process speeds
KW - Deep penetration
KW - Numerical modeling
KW - Ray tracing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532170
DO - https://doi.org/10.3390/met11081319
SN - 2075-4701
VL - 11
IS - 8
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fu, B.
A1 - Shen, J.
A1 - Suhuddin, U.
A1 - Chen, T.
A1 - dos Santos, J.
A1 - Klusemann, B.
A1 - Rethmeier, Michael
T1 - Improved mechanical properties of cast Mg alloy welds via texture weakening by differential rotation refill friction stir spot welding
N2 - Cast magnesium alloys welds produced by refill friction stir spot welding (refill FSSW) show low lap shear strength (LSS) and constantly fail in stirred zone (SZ) shear mode. The cause is most probably related to the heavily textured microstructure. Here, to re-engineer the resulting microstructure, we pro- pose a novel process variant, the differential rotation refill FSSW (DR-refill FSSW). DR-refill FSSW stim- ulates discontinuous dynamic recrystallization and produces a bimodal microstructure with weakened texture. Therefore, the deformation incompatibility between SZ and thermal-mechanically affected zone is avoided. The welds have 50% higher LSS than that of standard refill FSSW welds, and fail in a different failure mode, i.e., SZ pull-out mode. DR-refill FSSW provides a new and effective strategy for improving the performance of spot welds based on microstructural engineering.
KW - Refill friction stir spot welding
KW - Magnesium Alloy
KW - Texture
KW - EBSD
KW - Plastic deformation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536885
DO - https://doi.org/10.1016/j.scriptamat.2021.114113
SN - 1359-6462
VL - 203
SP - 114113
PB - Elsevier Ltd.
AN - OPUS4-53688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winterkorn, René
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Wire arc additive manufacturing with novel Al-Mg-Si filler wire - Assessment of weld quality and mechanical properties
N2 - Wire arc additive manufacturing enables the production of near-net shape large-volume metallic components leveraging an established industrial base of welding and cladding technology and adapting it for layer-wise material deposition. However, the complex relationship between the process parameters and resulting mechanical properties of the components still remains challenging. In case of high-strength Al-Mg-Si aluminum alloys, no commercial filler wires are yet available due the high susceptibility of solidification cracking as well as the necessary efforts to obtain acceptable mechanical properties. To address this need, we evaluated a novel filler wire based on AlMg0.7Si doped with a Ti5B1 master alloy to foster fine equiaxed grains within the deposited metal. The correlation between the process parameters and component quality was examined by analyzing the size and distribution of pores as well as the grain morphology. Furthermore, we evaluated the influence of different post-weld heat treatment strategies to achieve mechanical properties corresponding to the reference wrought material. We demonstrated that fine equiaxed grains in the weld metal reduced the susceptibility of solidification cracking significantly. The novel AlMg0.7Si-TiB (S Al 6063-TiB) filler wire facilitated wire arc additive manufacturing of high-strength aluminum components with mechanical properties that were almost as superior as the corresponding wrought base material.
KW - Wire arc additive manufacturing
KW - Precipitation hardening aluminum alloys
KW - AlMg0.7SiTiB filler wire
KW - Grain refinement
KW - Mechanical properties
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538327
DO - https://doi.org/10.3390/met11081243
SN - 2075-4701
VL - 11
IS - 8
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-53832
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Elucidation of the Bulging Effect by an Improved Ray-Tracing Algorithm in Deep Penetration Wire Feed Laser Beam Welding and its Influence on the Mixing Behavior
N2 - Herein, an improved ray-tracing routine using a virtual mesh refinement approach is adopted in a 3D transientmultiphysics computational fluid Dynamics model for deep penetration wire feed laser beam welding. In a previous study, it was shown that the improved localization of the reflection points of the subrays within the keyhole leads to a more realistic development of the keyhole Depth being validated with experimental results. Another effect investigated in Detail herein is a drastic change in the flow behavior in the weld pool, which promotes the occurrence of a necking area in the solidification line and subsequent bulging under specific circumstances. This has a detrimental effect on the filler material element transport in the weld pool, leading to an inhomogeneous dilution of the added material. The numerical observations are backed up by experimentally obtained data, allowing to provide a clear physics-based explanation of the reduced mixing behavior of the filler wire in the melt pool.
KW - Bulging effects
KW - Numerical welding simulations
KW - Ray-tracing methods
KW - Wire feed laser beam welding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543322
DO - https://doi.org/10.1002/adem.202101299
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-54332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - The bulging effect and its relevance in high power laser beam welding
N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and an infrared camera is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs more frequently during partial penetration above 6 mm and complete penetration above 8 mm penetration depth, respectively. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.
T2 - 18th Nordic Laser Materials Processing Conference (18th NOLAMP)
KW - High-power laser beam welding
KW - Bulge effect
KW - Solidification cracking
KW - Multi-physical modelling
KW - Metal mixing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539149
DO - https://doi.org/10.1088/1757-899X/1135/1/012003
VL - 1135
IS - 012003
SP - 1
EP - 11
PB - IOP Publishing
AN - OPUS4-53914
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support
N2 - One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds.
T2 - X International Conference «Beam Technologies & Laser Application»
KW - Laser hybrid welding
KW - Magnetic bath support
KW - Plasma-cut samples
KW - Thick plate welding
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539248
DO - https://doi.org/10.1088/1742-6596/2077/1/012007
VL - 2077
IS - 012007
SP - 1
EP - 8
PB - IOP Publishing
AN - OPUS4-53924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghata, Anupama
A1 - Bernges, Tim
A1 - Maus, Oliver
A1 - Wankmiller, Björn
A1 - Naik, Aakash
A1 - Bustamante, Joana
A1 - Gaultois, Michael W.
A1 - Delaire, Olivier
A1 - Hansen, Michael Ryan
A1 - George, Janine
A1 - Zeier, Wolfgang G.
T1 - Exploring the Thermal and Ionic Transport of Cu+ Conducting Argyrodite Cu7PSe6
N2 - AbstractUnderstanding the origin of low thermal conductivities in ionic conductors is essential for improving their thermoelectric efficiency, although accompanying high ionic conduction may present challenges for maintaining thermoelectric device integrity. This study investigates the thermal and ionic transport in Cu7PSe6, aiming to elucidate their fundamental origins and correlation with the structural and dynamic properties. Through a comprehensive approach including various characterization techniques and computational analyses, it is demonstrated that the low thermal conductivity in Cu7PSe6 arises from structural complexity, variations in bond strengths, and high lattice anharmonicity, leading to pronounced diffuson transport of heat and fast ionic conduction. It is found that upon increasing the temperature, the ionic conductivity increases significantly in Cu7PSe6, whereas the thermal conductivity remains nearly constant, revealing no direct correlation between ionic and thermal transport. This absence of direct influence suggests innovative design strategies in thermoelectric applications to enhance stability by diminishing ionic conduction, while maintaining low thermal conductivity, thereby linking the domains of solid‐state ionics and thermoelectrics. Thus, this study attempts to clarify the fundamental principles governing thermal and ionic transport in Cu+‐superionic conductors, similar to recent findings in Ag+ argyrodites.
KW - Thermoelectrics
KW - Phonons
KW - Chemically Complex Materials
KW - DFT
KW - Bonding Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608866
DO - https://doi.org/10.1002/aenm.202402039
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-60886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ghosh, Sheuly
A1 - Ueltzen, Katharina
A1 - George, Janine
A1 - Neugebauer, Jörg
A1 - Körmann, Fritz
T1 - Chemical ordering and magnetism in face-centered cubic CrCoNi alloy
N2 - The impact of magnetism on chemical ordering in face-centered cubic CrCoNi medium entropy alloy is studied by a combination of ab initio simulations, machine learning potentials, and Monte Carlo simulations. Large magnetic energies are revealed for some mixed L12 /L10 type ordered configurations, which are rooted in strong nearest-neighbor magnetic exchange interactions and chemical bonding among the constituent elements. There is a delicate interplay between magnetism and stability of MoPt2 and L12 /L10 type of ordering which may explain opposing experimental and theoretical findings.
KW - Bonding analysis
KW - Alloys
KW - Magnetism
KW - Material design
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600040
DO - https://doi.org/10.21203/rs.3.rs-3978660/v1
SN - 2693-5015
SP - 1
EP - 13
PB - Research Square Platform LLC
CY - Durham, NC
AN - OPUS4-60004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merz, Benjamin
A1 - Schmidt, Jonathan
A1 - Poka, Konstantin
A1 - Mohr, Gunther
A1 - Polte, Julian
A1 - Hilgenberg, Kai
T1 - Impact of illumination technique on the detectability of irregularities in high-resolution images of visual in-situ process monitoring in Laser Powder Bed Fusion
N2 - The layerwise geometry build-up of additive manufacturing (AM) enables the possibility of in-situ process monitoring. The objective is the detection of irregularities during the build cycle, ensuring component quality and process stability. Focus of this work is the visual in-situ monitoring of the process of powder bed fusion with laser beam of metals (PBF-LB/M). Current state of the art visual monitoring systems for PBF-LB/M are limited by low resolution, allowing the detection of gross flaws. In this work a 65 Mpixel high-resolution monochrome camera is integrated into a commercial PBF-LB/M machine enabling a spatial resolution of approx. 17.2 µm/Pixel. The observed inhomogeneities are clustered into directly detectable irregularities, and indirectly detectable irregularities that can be inferred from the surface. In parallel, two different illumination techniques are realized in the process chamber and compared. The impact of the distinct illumination technique, direct light and dark field, on the identification of irregularities is evaluated.
KW - Powder bed fusion with laser beam of metals
KW - In-situ monitoring
KW - High-resolution camera
KW - Illumination technique
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610929
DO - https://doi.org/10.1016/j.procir.2024.08.079
SN - 2212-8271
VL - 124
SP - 98
EP - 103
PB - Elsevier B.V.
AN - OPUS4-61092
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martins, Ines
A1 - Al-Sabbagh, Dominik
A1 - Bentrup, U.
A1 - Marquardt, Julien
A1 - Schmid, Thomas
A1 - Scoppola, E.
A1 - Kraus, Werner
A1 - Stawski, Tomasz
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
A1 - Weidner, Steffen
A1 - Emmerling, Franziska
T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate
N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure.
KW - Bismuth
KW - In situ EXAFS
KW - In situ SAXS/WAXS
KW - Lacunary Keggin ion
KW - Polyoxometalates
KW - Self-assembly
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546823
DO - https://doi.org/10.1002/chem.202200079
SN - 0947-6539
VL - 28
IS - 27
SP - 1
EP - 7
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - Entwicklung einer neuartigen Fügetechnologie
N2 - Vorstellung einer neuartigen Fügetechnologie für artungleiche Werkstoffe (Aluminium und Stahl) mit Hilfe von Laserstrahlschweißen und elektromagnetischer Schmelzbadbeeinflussung.
T2 - Assistentenseminar
CY - Braunlage, Germany
DA - 25.09.2019
KW - Laserstrahlschweißen
KW - Artungleiche Werkstoffe
KW - Elektromagnetische Schmelzbadbeeinflussung
KW - Fügetechnologie
KW - Stahl und Aluminium
PY - 2020
SN - 978-3-96144-071-9
VL - 357
SP - 34
EP - 43
PB - DVS Media GmbH
CY - Deutschland, Düsseldorf
AN - OPUS4-51052
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dzugan, J.
A1 - Lucon, E.
A1 - Koukolikova, M.
A1 - Li, Y.
A1 - Rzepa, S.
A1 - Yasin, M.S.
A1 - Shao, S.
A1 - Shamsaei, N.
A1 - Seifi, M.
A1 - Lodeiro, M.
A1 - Lefebvre, F.
A1 - Mayer, U.
A1 - Olbricht, Jürgen
A1 - Houska, M.
A1 - Mentl, V.
A1 - You, Z.
T1 - ASTM interlaboratory study on tensile testing of AM deposited and wrought steel using miniature specimens
N2 - An interlaboratory study, involving eigth international laboratories and coordinated by COMTES FHT (Czech Republic), was conducted to validate tensile measurements obtained using miniature specimens on additively manufactured (AM) components and artifacts. In addition to AM 316L stainless steel (316L SS), a wrought highstrength steel (34CrNiMo6V, equivalent to AISI 4340) was also used. Based on the results, a precision statement in accordance with ASTM E691 standard practice was developed, intended for inclusion in a proposed annex to the ASTM E8/E8M tension testing method. The primary outcomes of the study highlighted the agreement between yield and tensile strength measured from miniature and standard-sized tensile specimens. Furthermore, most tensile properties exhibited similar standard deviations, offering users insight into the efficacy of miniature specimen applications.
KW - 316L stainless steel
KW - Additive manufacturing
KW - High-strength steel
KW - Miniature specimens
KW - Tensile tests
PY - 2024
DO - https://doi.org/10.1016/j.tafmec.2024.104410
SN - 0167-8442
VL - 131
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böhne, Chr.
A1 - Meschut, G.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Avoidance of liquid metal embrittlement during resistance spot welding by heat input dependent hold time adaption
N2 - Liquid metal embrittlement (LME) cracking can occur during resistance spot welding (RSW) in zinc-coated advanced high-strength steels (AHSS) for automotive production. In this study, a methodological variation of hold time is performed to investigate the process-related crack influence factors. A combination of numerical and experimental investigations confirms, that the extent of heat dissipation and re-heating of the sheet surface can be influenced and thus the degree of crack formation can be controlled in a targeted manner by the parameterisation of the hold time. The temperature and stress history of crack-free and crack-afflicted spot welds are analysed and a conclusion on the borders defining the LME active region is derived.
KW - Liquid metal embrittlement
KW - Crack
KW - Advanced high-strength steels
KW - Resistance spot welding
KW - Hold time
KW - Heat input
KW - Simulation
PY - 2020
DO - https://doi.org/10.1080/13621718.2020.1795585
SN - 1362-1718
VL - 25
IS - 7
SP - 617
EP - 624
PB - Taylor Francis Online
AN - OPUS4-51096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bakir, Nasim
T1 - Observation of the weld pool shape in partial penetration welding and its influence on solidification crack formation for high-power laser beam welding
N2 - Solidification cracking is still a particular problem in laser beam welding, especially in the welding of thick-walled plates. In this study, the influence of weld pool geometry on solidification cracking in partial penetration welding of thick plates is a subject of discussion. For this purpose, a special experimental setup of steel and quartz glass in butt configuration and lateral with high speed camera was used to capture the weld pool shape. Additionally, laser beam welding experiments were carried out to compare the crack positions and the cross section with the high-speed camera observations. The results showed a bulge in the weld pool root separated from the upper region by a nick area. This leads to the fact that three different longitudinal lengths with different solidification areas are taking place. This temporal sequence of solidification strongly promotes the solidification cracks in the weld root.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - Solidification cracking
KW - Laser beam welding
KW - Partial penetration
PY - 2021
AN - OPUS4-53586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Experimental and numerical study on the influence of the laser hybrid parameters in partial penetration welding on the solidification cracking in the weld root
N2 - In this study, the influence of the welding speed, the arc power, and the laser focal position on the solidification crack formation for partial penetration laser hybrid–welded thick-walled plates was investigated.
The solidification cracking in the weld root is a result of interaction between metallurgical and geometrical and thermomechanical factors.
Experimentally, a direct correlation between the welding speed and the crack number was observed. That is by reducing the welding velocity, the crack number was decreased. The focal position shows also a significant influence on the crack number. By focusing the laser on the specimen surface, the crack number has been significantly diminished.
The wire feed speed showed a very slight influence on the crack formation. That is due to the large distance between the critical region for cracking and the arc region.
The numerical model shows a high stress concentration in the weld root for both components (vertical and transversal).
Numerically, the reduced welding speed showed a strong impact on stress, as the model demonstrated a lower stress amount by decreasing the welding speed.
The metallurgical factors, such as the assumed accumulation of the low-melting eutectics in the weld root, should be a contribution for solidification cracking, where the tensile stress is acting.
KW - Laser hybrid welding
KW - Solidification cracking
KW - Partial penetration welding
KW - Weld root
KW - Numerical simulation
PY - 2020
DO - https://doi.org/10.1007/s40194-020-00847-w
VL - 64
SP - 501
EP - 511
PB - Springer
AN - OPUS4-50625
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven materials discovery and understanding
N2 - Developments in density functional theory (DFT) calculations, their automation and therefore easier access to materials data have enabled ab initio high-throughput searches for new materials for numerous applications. These studies open up exciting opportunities to find new materials in a much faster way than based on experimental work alone. However, performing density functional theory calculations for several thousand materials can still be very time consuming. The use of, for example, faster chemical heuristics and machine-learned interatomic potentials would allow to consider a much larger number of candidate materials. In addition to DFT based high-throughput searches, the seminar will discuss two possible ways to accelerate high-throughput searches.
Using data analysis on the structures and coordination environments of 5000 oxides, we were able to investigate a chemical heuristic – the famous Pauling rules – regarding its usefulness for the fast prediction of stable materials.
We have also investigated how machine-learned interatomic potentials can be used to accelerate the prediction of (dynamically) stable materials. The use of these potentials makes vibrational properties accessible in a much faster way than based on DFT. Our results based on a newly developed potential for silicon allotropes showed excellent agreement with DFT reference data (agreement of the frequencies within 0.1-0.2 THz).
In addition, we have successfully used high-throughput calculations in the search for new candidate materials for spintronic applications and ferroelectrics
T2 - ETSF Webinar
CY - Online meeting
DA - 25.06.2021
KW - High-throughput computations
KW - Data analysis
KW - Machine learning
PY - 2021
AN - OPUS4-52980
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Karkhin, Victor
A1 - Bachmann, Marcel
A1 - Khomich, Pavel
A1 - Rethmeier, Michael
T1 - МОДЕЛИРОВАНИЕ ГИДРОДИНАМИЧЕСКИХ И ТЕПЛОВЫХ ПРОЦЕССОВ ПРИ ЛАЗЕРНОЙ СВАРКЕ СО СКВОЗНЫМ ПРОПЛАВЛЕНИЕМ
N2 - Разработана модель физических процессов при сварке плавлением на основе концепции эквивалентных источников теплоты. Модель включает в себя две части: термогидродинамику сварочной ванны и теплопроводность свариваемого тела вне ванны. В задаче термогидродинамики учитываются температурные зависимости свойств материала, форма парогазового канала, термокапиллярная и естественная конвекция, фазовые превращения и другие физические явления.Приведено решение задачи термогидродинамики методом конечных элементов на примере сварки стальной пластины толщиной 15 мм со сквозным проплавлением лазерным лучом (по технологии "замочная скважина"). Показано, что термокапиллярная конвекция жидкого металла является основной причиной сложной выпукло-вогнутой формы границы ванны с увеличенными размерами в приповерхностных областях. Получено удовлетворительное совпадение расчетных и экспериментальных размеров сварочной ванны.
KW - ЛАЗЕРНАЯ СВАРКА
KW - СВАРОЧНАЯ ВАННА
KW - ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ
KW - ГИДРОДИНАМИКА
KW - КОНВЕКЦИЯ
KW - ТЕПЛОПРОВОДНОСТЬ
KW - ТЕМПЕРАТУРНОЕ ПОЛЕ
KW - МЕТОД КОНЕЧНЫХ ЭЛЕМЕНТОВ
PY - 2020
SN - 0491-6441
SP - 58
EP - 69
AN - OPUS4-50290
LA - rus
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Neueste Entwicklungen im Bereich des Hochleistungslaserstrahl- und Hybridschweißens von hohen Blechdicken
N2 - Bislang kommt das Laserstrahlschweißen bzw. Laserhybridschweißen hauptsächlich bei Dickblechen mit einer Wandstärke von bis zu 15 mm zum Einsatz. Für Anwendungen über 20 mm war dieses Verfahren aufgrund einiger Herausforderungen bisher nur bedingt realisierbar. Eine von der Bundesanstalt für Materialforschung und -prüfung (BAM) entwickelte elektromagnetische Schmelzbadunterstützung ermöglicht nun ein einlagiges Schweißen von bis zu 30 mm Wandstärke.
KW - Laserstrahlschweißen
KW - Laserhybridschweißen
KW - Modellierung
KW - Elektromagnetische Schmelzbadunterstützung
KW - Kaltzähe Stähle
PY - 2020
VL - 2
SP - 26
EP - 30
PB - DVV Media Group GmbH
CY - Hamburg
AN - OPUS4-51632
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
T1 - Structural evolution of ZrV2O7: supercell persistence revealing local and global structure duality
N2 - In the AM2O7 family of negative thermal expansion materials (NTE), evidence of supercell at room temperature was reported following the Völlenke et al. discovery of missed superlattice due to the apparent linearity of the M-O-M bond in GeP2O7. Korthuis et al. and Khosrovani et al. demonstrated it to be true for cubic ZrV2O7 as well. It was concluded that at room temperature, the structure consists of 27 'subcells' with bent M2O7 groups that appear to form a linear configuration due to refinement of averaged position. However, around 100 °C, the transition to the “parent” cell was reported, where the cell volume increases, and the M-O-M angles are constrained by the Pa-3 space group symmetry to be 180°.
We followed structural changes in the ZrV2O7 at high temperatures to demonstrate partial disorder within the crystal, local and global structural duality and supercell persistence at high temperatures. Total scattering measurements and Pair Distribution Function (PDF) analysis revealed that the experimental pattern cannot be fitted with the “parent structure” model, and only the 3×3×3 supercell model can correspond to local and global structures throughout the full 25-700 °C temperature range.
We also show how short and long-range order within the crystal changes when approaching the phase transition, which might indicate the existence of coherent structural domains that evolve between order and disorder with increasing temperature. We further hypothesize how this can be related to the negative thermal expansion mechanism and the interpretation of structure solutions presenting data from high-temperature X-ray absorption fine structure (XAFS) and Transmission Electron Microscopy (TEM) measurements.
T2 - 5th International Symposium on Negative Thermal Expansion and Related Materials (ISNTE-5)
CY - Porto, Portugal
DA - 29.07.2025
KW - NTE
KW - Ab initio
KW - PDF
KW - CSM
PY - 2025
AN - OPUS4-63874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - High-power hybrid laser arc welding of thick materials with electromagnetic weld pool support
N2 - In addition to the many advantages of deep penetration, increased welding speed and a low sensitivity to manufacturing tolerances such as gap and edge offset, the hybrid laser arc welding (HLAW) process is used increasingly in industrial applications such as shipbuilding or pipeline manufacturing. Nonetheless, thick-walled sheets with a wall thickness of 20 mm or more are still multi-pass welded using the arc welding process, due to increased process instability by increasing laser power. Welding at reduced speed, especially in a flat position, leads to an irregular formation of the root part such as dropping. The hydrostatic pressure exceeds the surface tension, which decreases with increasing seam width. In order to prevent gravity drop-outs, the use of a melt pool support is necessary. Usual weld pool supports such as ceramic or powder supports require time-consuming mechanical detachment. The electromagnetic weld pool support system, which is described in this study, operates without contact and based on generating Lorentz forces in the weld pool. An externally applied oscillating magnetic field induces eddy currents and generates an upward directed Lorentz force, which counteracts the hydrostatic pressure. This allows single-pass welds up to 30 mm by hybrid laser arc welding process with a 20-kW fibre laser. Moreover, it is favoured by the diminished welding speed the cooling rate which leads to an improvement of the mechanical-technological properties of the seams – the lower formation of martensite in the microstructure enables better Charpy impact toughness. The electromagnetic weld pool support extends the limitation of the laser hybrid welding process in the thick sheet area. By adapting the electromagnetic weld pool support to the laser and laser hybrid welding process, the application potential of these technologies for industrial implementation can be drastically increased.
T2 - 23rd Technical Conference on Welding and Joining Technologies
CY - Irun, Spain
DA - 07.03.2023
KW - Laser hybrid welding
KW - Thick-walled steel
KW - Electromagnetic backing
KW - High-power laser
PY - 2023
AN - OPUS4-58613
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - In-situ temperature measurements of the LMD process by IR-spectroscopy and Thermography
N2 - Temperature measurements of the LMD process by IR-spectroscopy and Thermography are presenet and compared.
T2 - 2st Workshop on In-situ Monitoring and Microstructure Development in Additive Manufacturing
CY - Online meeting
DA - 19.04.2021
KW - Additive Manufacturing
KW - Thermography
PY - 2021
AN - OPUS4-52565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Untersuchung zur Herstellung von Cu-Strukturen mittels Wire Electron Beam Additive Manufacturing
N2 - Das Additive Manufacturing gewinnt zunehmend an Bedeutung für die Fertigung metallischer Bauteile im industriellen Umfeld. Hierbei wird zunehmend auch auf drahtförmige Ausgangswerkstoffe gesetzt, da diese Vorteile im Handling bieten, bereits in der Industrie etabliert sind und sich in der Regel durch geringere Beschaffungskosten auszeichnen. In den letzten Jahren entwickelte sich neben den bereits im großen Umfeld untersuchten Wire-DED-Verfahren auch eine Prozessvariante unter Nutzung des Elektronenstrahls zur industriellen Marktreife. Dabei zeigt die als Wire Electron Beam Additive Manufacturing bezeichnete Technologie besondere Vorteile gegenüber anderen, zumeist Laser- oder Lichtbogen-basierten DED-Prozessen. Das Verfahren bietet vor allem Potenzial für die Verarbeitung von hochleitfähigen, reflektierenden oder oxidationsgefährdeten Werkstoffen. Insbesondere für die Herstellung von Bauteilen aus Kupferlegierungen zeigt sich der Elektronenstrahl als besonders geeignet. Um das Verfahren einem breiten Anwenderkreis in der Industrie zugänglich zu machen, fehlen jedoch übergreifende Daten zu Leistungsfähigkeit, Prozessgrenzen und Anwendungsmöglichkeiten. Die vorliegende Untersuchung beschäftigt sich mit dieser Problemstellung am Beispiel zweier Cu-Werkstoffe. Dabei werden ein korrosionsbeständiger Werkstoff aus dem maritimen Bereich sowie eine Bronze mit guten Verschleißeigenschaften aus dem Anlagenbau getestet.
Über mehrstufige Testschweißungen wurden die physikalisch möglichen Prozessgrenzen ermittelt und Rückschlüsse über die Eignung der Parameter zum additiven Aufbau gezogen. Hierfür wurden zunächst optimale Bereiche für den Energieeintrag anhand von Volumenenergie sowie mögliche Schweißgeschwindigkeiten untersucht.
Anschließend wurde die Skalierbarkeit des Prozesses anhand von Strahlstrom und Drahtvorschub getestet.
Als wesentliche Zielgrößen wurden dabei Spurgeometrie, Aufmischung und Härte herangezogen. Die Eignung der ermittelten Parameter wurde im letzten Schritt exemplarisch anhand einer additiven Testgeometrie in Form eines Zylinders nachgewiesen.
T2 - DVS Congress 2022 Große Schweißtechnische Tagung DVS CAMPUS
CY - Koblenz, Germany
DA - 19.09.2022
KW - WEBAM
KW - Electron beam
KW - EBAM
KW - Wire electron beam additive manufacturing
PY - 2022
SN - 978-3-96144-189-1
VL - 382
SP - 446
EP - 454
PB - DVS Media
AN - OPUS4-56058
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaurasia, Prashant Kumar
A1 - Cagtay, Fabry
A1 - Andreas, Pittner
A1 - Rethmeier, Michael
T1 - Automated in situ monitoring and analysis of process signatures and build profiles during wire arc directed energy deposition
N2 - Wire arc directed energy deposition (DED-Arc) is an emerging metal additive manufacturing process to build near-net shaped metallic parts in a layer-by-layer with minimal material wastage. Automated in situ monitoring and fast-responsive analyses of process signatures and deposit profiles during DED-Arc are in ever demand to print dimensionally consistent parts and reduce post-deposition machining. A comprehensive experimental investigation is presented here involving real-time synchronous measurement of arc current, voltage, and the deposit profile using a novel multi-sensor monitoring framework integrated with the DED-Arc set-up. The recorded current–voltage transients are used to estimate the time-averaged arc power, and energy input in real time for an insight of the influence of wire feed rate and printing travel speed on the deposit characteristics. A unique attempt is made to represent the geometric profiles of the single-track deposits in a generalized mathematical form corresponding to a segmented ellipse, which has exhibited the minimum root-mean-square error of 0.03 mm. The dimensional inconsistency of multi-track deposits is evaluated quantitatively in terms of waviness using build profile monitoring and automated estimation, which is found to increase with an increase in step-over ratio and energy input. For the multi-track mild steel deposits, the suitable range of step-over ratio for the minimum surface waviness is observed to lie between 0.6 and 0.65. Collectively, the proposed framework of synchronized process monitoring and real-time analysis provides a pathway to achieve dimensionally consistent and defect-free parts, and highlights the potential for closed-loop control systems for a wider industrial application of DED-Arc.
T2 - IIW Annual Assembly 2025
CY - Genova, Italy
DA - 23.06.2025
KW - Additive Manufacturing
KW - Arc welding
KW - Real-time monitoring and control
KW - Dimensional inconsistency
KW - DED-arc
PY - 2025
AN - OPUS4-65231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
T1 - Wire arc additive manufacturing of high strength al-mg-si alloys
N2 - Direct energy deposition additive manufacturing technologies utilizing an electric arc offer a great potential in generating large volume metal components. However, the selection of process parameters that yield the desired near net shape design as well as the requested mechanical component behavior is not a trivial task due to the complex relationship. Exemplarily for additive manufacturing of high-strength precipitation hardening AlMgSi-aluminum alloy this paper shows the application of a newly developed matching solid welding wire doped with TiB as grain refiner. The correlation between process parameters and component quality is examined analyzing the size and distribution of pores as well as the grain morphology. Furthermore, the influences of different post-weld heat treatments are evaluated to meet the reference mechanical properties of the corresponding wrought material. Finally, the digital integration of the entire additive manufacturing chain enables an overall traceability of the relevant process steps which is the basis for a reliable subsequent quality assessment.
T2 - THERMEC'2023 International Conference on PROCESSING & MANUFACTURING OF ADVANCED MATERIALS: Processing, Fabrication, Properties, Applications
CY - Vienna, Austria
DA - 02.07.2023
KW - Additive Manufacturing
KW - DED-Arc
KW - Grain refinement
KW - High strength AlMgSi aluminium alloys
KW - Mechanical properties
PY - 2023
AN - OPUS4-59500
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Reconstruction of the time-averaged keyhole geometry in laser beam welding with electromagnetic support
N2 - In laser beam welding (LBW), the time-averaged keyhole shape provides statistical insights into the process compared to its transient geometry, offering a deeper understanding of the overall keyhole behaviour. However, capturing the time-averaged keyhole shape through experimental methods remains challenging. In this paper, a reconstruction algorithm for the time-averaged keyhole is developed and integrated into a three-dimensional transient multi-physical coupled numerical model. The algorithm can accurately capture the key characteristics of the keyhole, including its diameter and centroid. In addition, it can also successfully reproduce the experimentally observed phenomena of keyhole tailing. The overall shape of the keyhole appears smooth, without exhibiting obvious instability features. Furthermore, the time-averaged keyhole shape is compared under different magnetic flux densities when an external oscillating magnetic field is applied. The results indicate that the application of external magnetic fields does not fundamentally alter the overall keyhole shape. With increasing magnetic flux density, the trailing tail becomes progressively less pronounced and a noticeable increase in the curvature of the rear wall is observed. The standard deviation of the keyhole diameter can serve as an effective index for evaluating the keyhole instability. Keyhole stability in LBW of aluminium alloys is improved under the assistance of electromagnetic fields, and this stabilization is positively correlated with increasing magnetic flux density.
T2 - 14th International Seminar Numerical Analysis of Weldability
CY - Seggau, Austria
DA - 21.09.2025
KW - Laser beam welding
KW - Keyhole reconstruction
KW - Electromagnetic weld pool support
KW - Porosity defects
KW - Keyhole stability
PY - 2025
AN - OPUS4-64257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hernández García, María Amparo
T1 - Fabrication of low-cost free-form optical elements with standard LCD 3D printer for advanced opto-sensing and imaging applications
N2 - Nowadays, more and more complex optical elements are used in optical applications, but this can lead to high costs, a time-consuming manufacturing process and limited availability of unconventional elements. Therefore, in this work, we propose LCD 3D printing as alternative cost-effective technique, which is not only user-friendly but also free from design constrains and enables the fabrication of free-form optics. The tested polymeric materials showed promising results for printed optics and optical applications. In addition, 3D printed optical elements were evaluated in terms of their suitability in selected applications with opto-chemical sensors and imaging techniques, with results comparable to those obtained with the corresponding glass optical elements.
T2 - 12th European Optical Society Annual Meeting
CY - Naples, Italy
DA - 09.09.2024
KW - 3D-printing
KW - Optics
KW - Photopolymerization
KW - Rapid prototyping
KW - Sensors
PY - 2024
AN - OPUS4-61442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
A1 - Kising, Pascal
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Rethmeier, Michael
T1 - Numerical analysis of the dependency of the weld pool shape on turbulence and thermodynamic activity of solutes in laser beam welding of unalloyed steels
N2 - A three-dimensional numerical model was developed to accurately predict the steady-state weld pool shape in full penetration laser beam welding. The model accounts for the coupling between the heat transfer and the fluid dynamics by considering the effects of solid/liquid phase transition, thermo-capillary convection, natural convection, and phase-specific and temperature-dependent material properties up to the evaporation temperature. A fixed right circular cone was utilized as a keyhole geometry to consider the heat absorbed from the laser beam. The model was used to analyze the influence of the thermodynamic activity of solutes and turbulence on the weld pool shape. A mesh sensitivity analysis was performed on a hybrid mesh combining hexahedral and tetrahedral elements. For the case of full penetration laser beam welding of 8 mm thick unalloyed steel sheets, the dependence of the weld pool shape on the surface-active element sulfur was found to be negligible. The analysis of the results showed that a laminar formulation is sufficient for accurately predicting the weld pool shape since the turbulence has a minor impact on the flow dynamics in the weld pool. The validity of the numerical results was backed up by experimental measurements and observations, including weld pool length, local temperature history, and a range of metallographic crosssections.
T2 - 13th International Seminar Numerical Analysis of Weldability
CY - Seggau, Austria
DA - 04.09.2022
KW - Weld pool shape
KW - Numerical modeling
KW - Laser beam welding
KW - Thermo-capillary convection
KW - Turbulence
PY - 2023
SN - 978-3-85125-968-1
SN - 978-3-85125-969-8
SN - 2410-0544
VL - 13
SP - 161
EP - 188
PB - Verlag der Technischen Universität Graz
AN - OPUS4-58803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Experimental and numerical study on grain refinement in electromagnetic assisted laser beam welding of 5754 al alloy
N2 - Through experimental observation and auxiliary numerical simulation, this investigation studies the different types of grain refinement of 5754 aluminum alloy laser beam welding by applying a transverse oscillating magnetic field. Scanning electron microscope results have proved that the application of a magnetic field can reduce the average crystal branch width and increase its number. The interaction between the induced eddy current generated by the Seebeck effect and the applied external magnetic field produces a Lorentz force, which is important for the increase of the number of crystal branches. Based on the theory of dendrite fragmentation and the magnetic field-induced branches increment, the grain size reduction caused by the magnetic field is studied. Furthermore, the effects of the magnetic field are analyzed by combining a phase field method model and simulations of nucleation and grain growth. The grain distribution and average grain size after welding verifies the reliability of the model. In addition, the introduction of a magnetic field can increase the number of periodic three-dimensional solidification patterns. In the intersection of two periods of solidification patterns, the metal can be re-melted and then re-solidified, which prevents the grains that have been solidified and formed previously from further growth and generates some small cellular grains in the new fusion line. The magnetic field increases the building frequency of these solidification structures and thus promotes this kind of grain refinement.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, USA
DA - 16.10.2023
KW - Laser beam welding
KW - Magnetic field
KW - Crystal branch development
KW - Grain refinement
KW - Periodic solidification pattern
PY - 2023
SP - 1
EP - 10
AN - OPUS4-58809
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Rethmeier, Michael
T1 - Numerical study of the bulging effect in deep penetration laser beam welding
N2 - This article is devoted to the study of the bulging effect in deep penetration laser beam welding. The numerical results of the investigations are based upon experimental results from previous studies to reveal the relationship between the bulging effect and the hot cracking formation, as well as the mixing of alloying elements in the weld pool. The widening of the molten pool in its center area can be observed in full penetration as well as in partial penetration welds on 8 mm and 12 mm thick structural steel plates, respectively. The weld pool shape is extracted from the simulations to evaluate the extent of the necking of the solidification line as well as the bulging phenomena and its influence on the hot cracking phenomena. Relying on an earlier numerical study utilizing a fixed keyhole, simulation models considering a dynamic keyhole are developed thereto. Additionally, the mixing behavior of alloying elements during partial penetration is investigated. The link between the bulge and the studied phenomena is found to be significant.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - Deep penetration laser beam welding
KW - Welding simulation
KW - Solidification cracking
KW - Bulging effect
PY - 2021
SP - 1
EP - 8
AN - OPUS4-52848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
A1 - Fabry, Çağtay
A1 - Rethmeier, Michael
A1 - Thiele, Marc
A1 - Baeßler, Matthias
A1 - Brauser, S.
T1 - SmartWeld - Leichtbautechnik für Tragstrukturen von Offshore Windenergieanlagen
N2 - Die Anwendung von Leichtbauprinzipien im Stahlbau, wie z.B. die Verwendung von aufgelösten Tragstrukturen, sog. Jackets-Fundamenten, bietet ein großes Potential zur Reduzierung des Ressourcenverbrauchs, insbesondere im Hinblick auf die benötigte Stahlmenge.
In diesem Vortrag zeigen wir die Potenziale einer vollständigen Digitalisierung der schweißtechnischen Fertigungs- und Prüfkette auf, um eine vollautomatische Fertigung sowie Qualitätsprüfung von Rohrknoten als Schlüsselelement von Jackets-Fundamenten zu ermöglichen. Darüber hinaus wird der Zusammenhang zwischen der Geometrie der Nahtform und der resultierenden Ermüdungsfestigkeit durch numerische Methoden unter Einbeziehung bionischer Prinzipien bewertet. Es wird gezeigt, dass Hohlprofilknoten vollautomatisch unter Berücksichtigung von Geometrietoleranzen geschweißt werden können. Darüber hinaus konnte die Nahtform gemäß den numerischen Modellen hergestellt werden, was ein großes Potenzial für eine verlängerte Lebensdauer bietet. Anschließend werden die Verbesserungen bei der Ressourceneffizienz und die Reduzierung der Kohlendioxidemissionen durch eine Lebenszyklusanalyse bewertet.
T2 - 11. Zukunftskonferenz Wind & Maritim
CY - Rostock, Germany
DA - 01.09.2022
KW - Offshore Windenergieanlagen
KW - Gründungsstrukturen
KW - Leichtbauprinzipien
KW - Automatisierte Fertigung
PY - 2022
AN - OPUS4-56654
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
T1 - Additive Manufacturing of High Strength Al-Mg-Si Alloys with DED-Arc
N2 - Direct energy deposition additive manufacturing technologies that utilize an electric arc have great potential for generating large volume metal components. However, selecting process parameters that yield the desired near net shape design and requested mechanical component behavior is not a trivial task due to the complex relationship between all process parameters and material characteristics. This presentation exemplifies the application of a newly developed solid welding wire doped with TiB to enhance grain refinement in the deposited metal for additive manufacturing based on DED-Arc of high-strength precipitation hardening AlMgSi-aluminum alloys. It is worth noting that the solid wire is the result of our preliminary metallurgical studies on grain refinement in aluminum weld metal.
Consequently, research focuses on the correlation between process parameters and component quality to understand the underlying mechanisms. This is crucial for evaluating a robust process parameter space that yields component quality in line with corresponding standards which are mainly taken from welding technology.
Specifically, we examine component quality by analyzing pore size and distribution, as well as grain morphology. To enhance the mechanical properties of the deposited metal, a post-weld heat treatment was conducted, comprising of solution treatment, quenching, and artificial aging. The study also evaluates the effects of various heat treatment strategies on the final mechanical properties of the material.
To demonstrate the applicability of 3D metal printing of high-strength aluminium alloys, a more complex demonstrator was created. It has been shown that DED-Arc can produce high-volume aluminium parts with the same quality as the corresponding subtractive processing strategy.
Additionally, the entire additive manufacturing chain has been digitally integrated, enabling traceability of all relevant process steps, which is essential for reliable subsequent quality assessment.
T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024
CY - Berlin, Germany
DA - 12.06.2024
KW - DED-Arc
KW - High-stength aluminium alloys
KW - Grain refinement
KW - Quality assurance
PY - 2024
AN - OPUS4-60248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - A statistical investigation of the laser energy absorption and keyhole stability in high-power laser beam welding
N2 - The behaviour of the weld pool in high-power laser beam welding is significantly influenced by laser absorption and keyhole stability, which determines the final weld qualities. However, their dynamic features and multi-coupled interactions make in-depth analyses difficult. This study addresses the challenges by conducting a thorough statistical evaluation of the effects of welding parameters on laser absorption and keyhole fluctuations, using experimental investigations and a well-validated numerical model. From a statistical aspect, the laser energy distribution and the keyhole collapse, commonly considered highly time-varying, show clear regularities. Three distinct regions of the time-averaged energy distribution are identified. The possibility of the keyhole collapse positions obeys a universal normal distribution. The statistical data show greater potential in revealing some well-known, industry-related but unclearly explained findings, such as the saturation of the weld penetration with increasing heat input and the physical basis of the contributions of different welding parameters in the porosity reduction.
T2 - The 14th International Seminar Numerical Analysis of Weldability
CY - Graz, Austria
DA - 21.09.2025
KW - Laser beam welding
KW - Energy absorption
KW - Keyhole stability
KW - Multi-physics modelling
PY - 2025
AN - OPUS4-64811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
T1 - Challenges in Modelling Dynamic Heat Sources in High-Power Laser Beam Welding
N2 - The amount of absorbed energy in the keyhole as well as its distribution is essential to model the laser beam welding process. The recoil pressure is a key determining factor for the macroscopic flow of the molten metal in the weld pool during high-power laser beam welding. Consequently, a realistic implementation of the laser radiation on the weld metal is crucial to obtain accurate simulation results.
The following developments on the laser-material interaction are discussed for the numerical simulation of the laser beam welding process. The first implemented improvements relate to locating the exact reflection points in the ray tracing method in the determination algorithm for the intersection of the reflected rays and the keyhole surface. A second correction refers to the numerical treatment of the Gaussian distribution of the laser beam, whose beam width is defined by a decay of the laser intensity by a factor of 1/e2 thus ignoring around 14 % of the total laser beam energy. In a third step, the laser radiation distribution in vertical direction was approximated according to the beam caustics. Finally, a virtual mesh refinement was adopted in the ray tracing routine. The obtained numerical results were validated with experimental measurements.
T2 - IIW Annual Assembly 2024
CY - Rhodes , Greece
DA - 07.07.2024
KW - Laser beam welding
KW - Numerical modeling
KW - Ray tracing
KW - Heat source modeling
PY - 2024
AN - OPUS4-60634
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
T1 - JaGeo/Advanced_Jobflow_Tutorial: v.0.1.0
N2 - This tutorial is aimed at developers who would like to develop workflows with Jobflow. This could include contributions to atomate2 and quacc. Jobflow workflows can also be executed with Fireworks on Supercomputers.
This tutorial includes information on how to write a job for jobflows, how to connect jobs to a workflow including dynamic features and how to store job results in databases. The structure of the workflow is inspired by workflows that have been developed for atomate2 and quacc.
This tutorial is also connected to google collab so that you can execute the code via their services.
Please access the tutorial here: https://jageo.github.io/Advanced_Jobflow_Tutorial/intro.html
KW - Automation
KW - Computational Materials Science
PY - 2023
UR - https://jageo.github.io/Advanced_Jobflow_Tutorial/intro.html
DO - https://doi.org/10.5281/zenodo.8004401
PB - Zenodo
CY - Geneva
AN - OPUS4-57588
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Artzt, K.
A1 - Rehmer, Birgit
A1 - Haubrich, J.
A1 - Ávila Calderón, Luis
A1 - Schoenstein, F.
A1 - Serrano-Munoz, Itziar
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Separation of the impact of residual stress and microstructure on the fatigue performance of LPBF Ti-6Al-4V at elevated temperature
N2 - Manufacturing defects, high residual stress (RS), and microstructures affect the structural integrity of laser powder bed fusion (LPBF) Ti-6Al-4V. In this study, the individual effect of these factors on fatigue performance at elevated temperature (300 °C) was evaluated. Material in as-built condition and subjected to post-processing, including two heat treatments and hot isostatic pressing, was investigated. It was found that in the absence of tensile RS, the fatigue life at elevated temperature is primary controlled by the defects; and densification has a much stronger effect than the considered heat treatments on the improvement of the mechanical performance.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Residual stress
KW - Fatigue performance
KW - Computed tomography
PY - 2021
DO - https://doi.org/10.1016/j.ijfatigue.2021.106239
SN - 0142-1123
VL - 148
SP - 106239
PB - Elsevier Ltd.
AN - OPUS4-52369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Putra, Stephen Nugraha
A1 - Meng, Xiangmeng
A1 - Yang, Fan
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Einfluss der temperaturabhängigen Modellierung der Laserstrahlabsorption auf die Schmelzbadgeometrie beim Hochleistungslaserstrahlschweißen
N2 - Der Absorptionsgrad metallischer Werkstoffe spielt bei Fügeprozessen mit einer Strahlungsquelle wie dem Hochleistungslaserstrahltiefschweißen eine bedeutende Rolle. Dieser beeinflusst die Menge der absorbierten Laserenergie, welche zum Aufschmelzen sowie zur lokalen Verdampfung des zu verbindenden Materials führt. Die Laserstrahlabsorption wird von vielen physikalischen Faktoren, z.B. Laserprofil, Laserwellenlänge, Materialeigenschaft sowie Temperatur, entschieden. Dennoch wird die Temperaturabhängigkeit in vielen Simulationsarbeiten häufig ignoriert und stattdessen ein empirisch angepasster Parameter zur Kalibrierung der Ergebnisse implementiert. Diese Vorgehensweise wirkt sich negativ auf die Zuverlässigkeit des numerischen Modells sowie auf die Vorhersagbarkeit der Simulationsergebnisse aus. In der vorliegenden Arbeit wird die Temperaturabhängigkeit des Laserabsorptionsgrades in ein selbstkonsistentes zweiphasiges Modell unter Berücksichtigung der gekoppelten 3D-Fluidströmung und Wärmeübertragung einbezogen. Die berechnete Laserstrahlabsorption wird durch die temperaturabhängigen Materialeigenschaften, die Lasercharakteristik und den Einfallswinkel des Laserstrahls bestimmt. Die freie Oberfläche jeder Phase wird mithilfe der Volume-of-Fluid Methode (VOF), berechnet und die Laser-Material-Wechselwirkung wird durch ein implementiertes Ray-Tracing-Verfahren modelliert, welches auf einem lokalisierten Level-Set-Algorithmus basiert. Anschließend wird die transiente Wärmeeinbringung und die Geometrie der Schweißnaht analysiert und mit dem temperaturunabhängigen Absorptionsmodell verglichen. Es wurde festgestellt, dass die Temperaturabhängigkeit der Laserabsorption entscheidend für die genaue Bestimmung der Wärmeeinbringung und der Schmelzbadgeometrie ist. Das entwickelte Modell wurde anhand der experimentellen Untersuchungen validiert und die Bedeutung der Temperaturabhängigkeit bei der Laserstrahlabsorption wurde für die Simulation des Laserstrahltiefschweißens quantifiziert.
T2 - 44. Assistentenseminar Füge- und Schweißtechnik
CY - Päwesin, Germany
DA - 20.09.2023
KW - Laser beam welding
KW - Numerical modeling
KW - Ray tracing method
KW - Weld pool dynamics
PY - 2024
UR - https://www.dvs-media.eu/de/neuerscheinungen/4671/44.-assistentenseminar-fuegetechnik
SN - 978-3-96144-267-6
VL - 394
SP - 57
EP - 68
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-60779
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Verbesserung der Übertragbarkeit eines künstlichen neuronalen Netzes zur Qualitätsvorhersage beim Widerstandspunktschweißen von hochfesten Stählen
N2 - Eine typische Automobilkarosserie kann bis zu 5000 Widerstandspunktschweißverbindungen aufweisen, welche hohen Qualitätsanforderungen genügen müssen. Daher ist eine durchgehende Prozessüberwachung unerlässlich. Die Transformation zur E-Mobilität in der Automobilindustrie und die damit einhergehende Reichweitenproblematik treiben die Entwicklung und Einführung neuer hochfester Stähle an. Dies resultiert in einem gesteigerten Fertigungsaufwand hinsichtlich einer stabilen Prozess-führung in der Fügetechnik. Um diesen Anstieg an Komplexität zu bewältigen, sind die Methoden der künstlichen Intelligenz ein geeignetes Mittel. Mit ihnen kann, durch Auswertung der Prozessparameter und -signale, die individuelle Schweißpunktqualität sichergesellt werden. Die Vorhersagegenauigkeit von neuen Daten, also das extrapolieren, stellt für die meisten Algorithmen eine große Herausforderung dar.
In dieser Arbeit wird ein künstliches neuronales Netz zur Vorhersage des Punktdurchmessers von Widerstandspunktschweißungen anhand von Prozessparametern implementiert. Die Vorhersagegenauigkeit und Extrapolationsfähigkeit des Modells wird durch die Auswertung des dynamischen Widerstandssignals verbessert.
Um die Extrapolationsfähigkeit zu untersuchen, wird die Vorhersagegenauigkeit des Modells mit Daten getestet, die sich in Bezug auf den Werkstoff und der Beschichtungszusammensetzung deutlich von den Trainingsdaten unterscheiden. Dazu wurden mehrere Schweißexperimente mit Werkstoffen verschiedener Hersteller durchgeführt und nur ein Teil der Daten in das Training einbezogen. Die Ergebnisse dieser Arbeit verdeutlichen den positiven Einfluss der Prozesssignale auf die Robustheit des Modells und die Skalierbarkeit der Algorithmen
künstlicher neuronaler Netze auf Daten außerhalb des Trainingsraums.
T2 - DVS Congress 2023 Große Schweißtechnische Tagung
CY - Essen, Germany
DA - 11.09.2023
KW - Widerstandspunktschweißen
KW - Hochfester Stahl
KW - Künstliche Intelligenz
KW - Neuronales Netz
KW - Fügequalität
PY - 2023
SN - 978-3-96144-230-0
SP - 772
EP - 779
AN - OPUS4-58693
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Karkhin, V.
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - A General Analytical Solution for Two-Dimensional Columnar Crystal Growth during Laser Beam Welding of Thin Steel Sheets
N2 - A technique for calculating the main solidification parameters for a two-dimensional columnar crystal growth during complete penetration laser beam welding of thin steel sheets was developed. Given that the weld pool interface is described by Lamé curves (superellipses) within the horizontal plane of growth, general analytical solutions were derived for the geometry of the crystal axis and the corresponding growth rate and cross-sectional area of the crystal. A dimensionless analysis was performed to provide insights on the dependence of the solidification parameters on the shape and dimensions of the rear part of the weld pool boundary. The derived solutions were applied for the case of complete penetration laser beam keyhole welding of 2 mm thick 316L austenitic chromium-nickel steel sheets. It was shown that the reconstruction of the weld pool boundary with Lamé curves provides higher accuracy and flexibility compared to results obtained with elliptical functions. The validity of the proposed technique and the derived analytical solutions was backed up by a comparison of the obtained solutions to known analytical solutions and experimentally determined shapes and sizes of the crystals on the top surface of the sheet. The dimensions of the calculated crystal axis correlated well with the experimentally obtained results.
KW - General analytical solutions
KW - Two-dimensional solidification
KW - Columnar crystal growth
KW - Lamé curves
KW - Laser beam welding
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576788
DO - https://doi.org/10.3390/app13106249
IS - 10
SP - 1
EP - 10
ET - 13
AN - OPUS4-57678
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of an external applied AC magnetic field on the melt pool dynamics at high-power laser beam welding
N2 - The study deals with the determination of the influence of an externally applied oscillating magnetic field on the melt pool dynamics in high power laser beam and hybrid laser arc welding processes. An AC magnet was positioned under the workpiece which is generating an upward directed electromagnetic force to counteract the formation of the droplets. To visualise the melt flow characteristics, several experiments were carried out using a special technique with mild steel from S355J2 with a plate thickness of up to 20 mm and a quartz glass in butt configuration. The profile of the keyhole and the melt flow were recorded with a highspeed camera from the glass side. Additionally, the influence of the magnetic field orientation to the welding direction on the filler material dilution on laser hybrid welding was studied with variating oscillation frequency. The element distribution over the whole seam thickness was measured with X-ray fluorescence (XRF). The oscillation frequency demonstrated a great influence on the melt pool dynamics and the mixing of the elements of the filler wire. The highspeed recordings showed, under the influence of the magnetic field, that the melt is affected under strong vortex at the weld root, which also avoids the formation of droplets.
T2 - 18th Nordic Laser Materials Processing Conference (18th NOLAMP)
KW - Laser beam welding
KW - AC magnetic field
KW - Melt pool dynamics
KW - Filler wire mixing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539231
DO - https://doi.org/10.1088/1757-899X/1135/1/012017
VL - 1135
IS - 012017
SP - 1
EP - 10
PB - IOP Publishing
AN - OPUS4-53923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marquardt, R.
A1 - Gook, S.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Handgeführtes Laserstrahlschweißen am T-Stoß eines niedrig legierten Stahls
N2 - Das handgeführte Laserstrahlschweißen gewinnt in der Industrie zunehmend an Bedeutung, da die hohe Produktivität und die einfache Handhabung Unternehmen wirtschaftliche Vorteile bieten. Derzeit ist der Einsatz in der Industrie jedoch auf Teile mit ästhetischen Anforderungen beschränkt, die häufig aus hochlegiertem Stahl bestehen. Um das Handschweißen mit Laserstrahl auch für Bauteile aus kostengünstigen Stähle mit guten mechanischen Eigenschaften einsetzen zu können, untersucht diese Studie den Einfluss des Schutzgases auf die Porosität am mikrolegierten Stahl HX340LAD mit einer Dicke von 1,5 mm. Getestet wurden die Gase Argon, Stickstoff, CO2 sowie Mischungen aus Argon und CO2 an T-Stöße mit Zusatzdraht. Die Qualifizierung der Porosität erfolgte gemäß DIN EN ISO 13919-1 an Querschliffen als auch mittels Röntgenuntersuchung. Die Ergebnisse zeigen, dass für diesen Stahl die Bewertungsgruppe B mittels CO2 als Schutzgas erreicht werden kann. Stickstoff führt zu Gruppe C, Argon zu D.
KW - Handgeführtes Laserstrahlschweißen
KW - HHLW
KW - Stahl
KW - Laser
PY - 2025
VL - 2025
IS - 06
SP - 44
EP - 47
PB - DVS Media
AN - OPUS4-63345
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - The influence of magnetic field orientation on metal mixing in electromagnetic stirring enhanced wire feed laser beam welding
N2 - The application of the electromagnetic stirring from an oscillating magnetic field can improve the metal mixing in wire feed laser beam welding. However, the extra parameters introduced in this technique make the selection of an optimal combination of process parameters more difficult. In the current study, besides the commonly concerned magnetic flux density and frequency, the influence of the magnetic field orientation (magnetic field angle) on the transport of filler metal is studied numerically and experimentally. Ex-situ X-ray fluorescence spectrometer measurements are used to map the metal mixing in the final weld. A three-dimensional transient multi-physical model is developed to reveal the deeper physical essence, considering the coupling between heat transfer, fluid flow, keyhole dynamics, element transport and magnetohydrodynamics. The spatial distribution of the laser energy on the keyhole wall is calculated by a ray tracing algorithm. The results show that the magnetic field with smaller angle with respect to the transverse direction provides better penetration capacity, and its stirring effect can reach the lower part of the molten pool. Therefore, the smaller magnetic field angle produces better metal mixing. A constant downward flow is formed at the lower part of the molten pool when magnetic field of 10° angle is applied, which brings the filler metal to the root region. As the magnetic field angle increases to 40°, the beneficial downward flow changes into a constant upward flow, resulting in a concentration of the filler metal in the upper region. This study provides further insight of the underlying physics in the electromagnetically enhanced laser beam welding, which may guide the optimization of parameters to achieve property homogeneity or to avoid potential defects.
KW - Laser welding
KW - Metal mixing
KW - Magnetic field
KW - Magnetohydrodynamics
KW - Multi-physical modelling
PY - 2021
DO - https://doi.org/10.1016/j.jmatprotec.2021.117135
VL - 294
SP - 117135
PB - Elsevier B.V.
AN - OPUS4-52469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - A statistical assessment of the laser energy absorption and keyhole stability in high-power laser welding
N2 - The behavior of the weld pool in high-power laser beam welding is significantly influenced by laser absorption and keyhole stability, which determines the final weld qualities. However, their dynamic features and multi-coupled interactions make in-depth analyses difficult. This study addresses the challenges by conducting a thorough statistical evaluation of the effects of welding parameters on laser absorption and keyhole fluctuations, using experimental investigations and a well-validated numerical model. From a statistical aspect, the laser energy distribution and the keyhole collapse, commonly considered to be highly time-varying, show clear regularities. Three distinct regions of the time-averaged energy distribution are identified. The possibility of the keyhole collapse positions obeys a universal normal distribution. The statistical data show greater potential in revealing some well-known, industry-related but unclearly explained findings, such as the saturation of the weld penetration with increasing heat input and the physical basis of the contributions of different welding parameters in the porosity reduction.
T2 - 78th IIW Annual Assembly
CY - Genoa, Italy
DA - 22.06.2025
KW - Laser beam welding
KW - Energy absorption
KW - Keyhole stability
PY - 2025
AN - OPUS4-64810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - Welding Process Data Management - openBIS workflows and lab integration
N2 - Arc welding processes are an important manufacturing technology applied to a wide range of critical materials and components such as offshore constructions, pressure vessels and additive manufacturing. Data management for experimental arc welding research faces the challenge of constantly changing experimental setups, incorporating a wide range of custom sensor integrations. Measurements include timeseries process and temperature recordings, 3D-geometry data and video recordings of the process from a sub-millisecond scale to multiple hour-long experiments. In addition, various manual pre-processing steps of the workpieces need to be considered to track the complete manufacturing process and its analysis – from raw materials to final dataset and publication.
As a unified RDM system, the BAM Data Store offers the capability to incorporate all steps – albeit not without its own challenges.
The talk gives an overview of the different workflows and processing steps along the welding experiments together with their integration into the BAM Data Store. Current solutions and ongoing integration work is explained and discussed. This includes the direct integration and upload of automated processing steps into the Data Store from different machines and sensors using custom Python APIs.
Ultimately the complete processing chain across multiple internal steps should be represented in the Data Store.
T2 - openBIS user group meeting 2025
CY - Berlin, Germany
DA - 22.09.2025
KW - Data Store
KW - Openbis
KW - Research Data Management
KW - Research data
KW - Digitalisation
PY - 2025
AN - OPUS4-64203
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, S.
A1 - Krieger, S.
A1 - Gumenyuk, Andrey
A1 - El-Batahgy, A. M.
A1 - Rethmeier, Michael
T1 - Notch impact toughness of laser beam welded thick sheets of cryogenic nickel alloyed steel X8Ni9
N2 - The paper deals with the investigations of the impact toughness of laser beam welded 14.5 mm thick sheets made of cryogenic steel X8Ni9 as a function of preheating. This 9% nickel alloyed steel is widely used in the liquefied natural gas (LNG) industry. An application of highly efficient welding processes such as high-power laser beam welding (LBW) in LNG sector requires an understanding of the interactions between the LBW process parameters and weld properties, in particular the impact toughness. The results show that the original fine-grained martensitic microstructure of the base metal (BM) is significantly changed by melting and crystallization during the LBW, what can lead to a decrease in the impact toughness of the weld metal (WM) below the required level. An optimal preheating temperature range leads to the favorable thermal welding cycle and is of remarkable importance for maintaining the notch impact toughness of laser beam welded joints of these thick steel sheets. A parameter window was identified in which V-notch impact toughness comparable to that of the BM at -196 °C was achieved.
KW - Cryogenic steel
KW - Laser beam welding
KW - Preheating
KW - Welding thermal cycle
KW - Microstructure
KW - Hardness
KW - V-notch impact toughness
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513250
DO - https://doi.org/10.1016/j.procir.2020.09.095
VL - 94
SP - 627
EP - 631
PB - Elsevier B.V.
AN - OPUS4-51325
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Pavlov, V.
A1 - Volvenko, S.
A1 - Rethmeier, Michael
T1 - In situ determination of the critical straining condition for solidification cracking during laser beam welding
N2 - A self-restraint hot cracking test (free edge test) was used in combination with a novel optical measurement technique to determine the critical straining conditions for solidification cracking for the stainless steel grade 1.4828 (AISI 309). The Lucas-Kanade algorithm for the optical flow (OF) calculation was implemented to obtain the full-field displacement and then the full-field strain.
The use of external laser illumination with appropriate filters allows to obtain good image quality with good contrast. The critical straining conditions required for solidification cracking can be obtained by means the proposed technique in the immediate vicinity of the solidification front. A very good repeatability was demonstrated for the used measurement technique. The critical straining conditions for solidification cracking for the tested steel und under this welding conditions has been detected
KW - Laser beam welding
KW - Solidification cracking
KW - Critical strain
KW - Critical strain rate
KW - Optical flow
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513070
DO - https://doi.org/10.1016/j.procir.2020.09.104
SN - 2212-8271
VL - 94
SP - 666
EP - 670
PB - Elsevier
AN - OPUS4-51307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Distortion-based validation of the heat treatment simulation of Directed Energy Deposition additive manufactured parts
N2 - Directed energy deposition additive manufactured parts have steep stress gradients and an anisotropic microstructure caused by the rapid thermo-cycles and the layer-upon-layer manufacturing, hence heat treatment can be used to reduce the residual stresses and to restore the microstructure. The numerical simulation is a suitable tool to determine the parameters of the heat treatment process and to reduce the necessary application efforts. The heat treatment simulation calculates the distortion and residual stresses during the process. Validation experiments are necessary to verify the simulation results. This paper presents a 3D coupled thermo-mechanical model of the heat treatment of additive components. A distortion-based validation is conducted to verify the simulation results, using a C-ring shaped specimen geometry. Therefore, the C-ring samples were 3D scanned using a structured light 3D scanner to compare the distortion of the samples with different post-processing histories.
KW - Directed Energy Deposition
KW - Additive Manufacturing
KW - Heat Treatment
KW - Numerical Simulation
KW - Finite Element Method
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513153
DO - https://doi.org/10.1016/j.procir.2020.09.146
VL - 94
SP - 362
EP - 366
PB - Elsevier B.V.
AN - OPUS4-51315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Hildebrandt, R.
A1 - Seifert, M.
A1 - George, Janine
A1 - Blaurock, S.
A1 - Botti, S.
A1 - Krautscheid, H.
A1 - Grundmann, M.
A1 - Sturm, C.
T1 - Determination of acoustic phonon anharmonicities via second-order Raman scattering in CuI
N2 - We demonstrate the determination of anharmonic acoustic phonon properties via second-order Raman scattering exemplarily on copper iodide single crystals. The origin of multi-phonon features from the second-order Raman spectra was assigned by the support of the calculated 2-phonon density of states. In this way, the temperature dependence of acoustic phonons was determined down to 10 K. To determine independently the harmonic contributions of respective acoustic phonons, density functional theory (DFT) in quasi-harmonic approximation was used. Finally, the anharmonic contributions were determined. The results are in agreement with earlier publications and extend CuI's determined acoustic phonon properties to lower temperatures with higher accuracy. This approach demonstrates that it is possible to characterize the acoustic anharmonicities via Raman scattering down to zero-temperature renormalization constants of at least 0.1 cm⁻¹.
KW - DFT
KW - Quasi-harmonic approximation
KW - Raman
KW - Phonons
KW - Anharmonicity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583699
DO - https://doi.org/10.48550/arXiv.2305.18931
SN - 2331-8422
SP - 1
EP - 14
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-58369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials
N2 - An in-depth insight into the chemistry and nature of the individual chemical bonds is essential for understanding materials. Bonding analysis is thus expected to provide important features for large-scale data analysis and machine learning of material properties. Such chemical bonding information can be computed using the LOBSTER software package, which post-processes modern density functional theory data by projecting the plane wave-based wave functions onto an atomic orbital basis. With the help of a fully automatic workflow, the VASP and LOBSTER software packages are used to generate the data. We then perform bonding analyses on 1520 compounds (insulators and semiconductors) and provide the results as a database. The projected densities of states and bonding indicators are benchmarked on standard density-functional theory computations and available heuristics, respectively. Lastly, we illustrate the predictive power of bonding descriptors by constructing a machine learning model for phononic properties, which shows an increase in prediction accuracies by 27% (mean absolute errors) compared to a benchmark model differing only by not relying on any quantum-chemical bonding features.
KW - Bonding Analysis
KW - DFT
KW - High-throughput
KW - Database
KW - Phonons
KW - Machine Learning
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582892
DO - https://doi.org/10.1038/s41597-023-02477-5
VL - 10
IS - 1
SP - 1
EP - 18
AN - OPUS4-58289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Process Setup and Boundaries of Wire Electron Beam Additive Manufacturing of High-Strength Aluminum Bronze
N2 - In recent years, in addition to the commonly known wire-based processes of Directed Energy Deposition using lasers, a process variant using the electron beam has also developed to industrial market maturity. The process variant offers particular potential for processing highly conductive, reflective or oxidation-prone materials. However, for industrial usage, there is a lack of comprehensive data on performance, limitations and possible applications. The present study bridges the gap using the example of the high-strength aluminum bronze CuAl8Ni6. Multi-stage test welds are used to determine the limitations of the process and to draw conclusions about the suitability of the parameters for additive manufacturing. For this purpose, optimal ranges for energy input, possible welding speeds and the scalability of the process were investigated. Finally, additive test specimens in the form of cylinders and walls are produced, and the hardness profile, microstructure and mechanical properties are investigated. It is found that the material CuAl8Ni6 can be well processed using wire electron beam additive manufacturing. The microstructure is similar to a cast structure, the hardness profile over the height of the specimens is constant, and the tensile strength
and elongation at fracture values achieved the specification of the raw material.
KW - Wire electron beam additive manufacturing
KW - Aluminum bronze
KW - Wire-based additive manufacturing
KW - EBAM
KW - DED-EB
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580890
DO - https://doi.org/10.3390/met13081416
VL - 13
IS - 8
SP - 1
EP - 16
PB - MDPI
AN - OPUS4-58089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huo, W.
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, K.
T1 - Strain Prediction Using Deep Learning during Solidification Crack Initiation and Growth in Laser Beam Welding of Thin Metal Sheets
N2 - The strain field can reflect the initiation time of solidification cracks during the welding process. The traditional strain measurement is to first obtain the displacement field through digital image correlation (DIC) or optical flow and then calculate the strain field. The main disadvantage is that the calculation takes a long time, limiting its suitability to real-time applications. Recently, convolutional neural networks (CNNs) have made impressive achievements in computer vision.
To build a good prediction model, the network structure and dataset are two key factors. In this paper, we first create the training and test sets containing welding cracks using the controlled tensile weldability (CTW) test and obtain the real strain fields through the Lucas–Kanade algorithm. Then, two new networks using ResNet and DenseNet as encoders are developed for strain prediction, called StrainNetR and StrainNetD. The results show that the average endpoint error (AEE) of the two networks on our test set is about 0.04, close to the real strain value. The computation time could be reduced to the millisecond level, which would greatly improve efficiency.
KW - Convolutional neural network
KW - Strain fields prediction
KW - Laser beam welding
KW - Solidification cracking
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570565
DO - https://doi.org/10.3390/app13052930
VL - 13
IS - 5
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-57056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Pauw, Brian Richard
A1 - Laskina, Sofya
A1 - Naik, Aakash
A1 - Smales, Glen Jacob
A1 - George, Janine
A1 - Breßler, Ingo
A1 - Benner, Philipp
T1 - "Ultima Ratio": Simulating wide-range X-ray scattering and diffraction
N2 - We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated patterns can be used to test holistic analysis models, and, since the diffraction intensity is on the same scale as the scattering intensity, may offer a novel pathway for determining the degree of crystallinity.
The "Ultima Ratio" strategy is demonstrated on a 64-nm Metal Organic Framework (MOF) particle, calculated from Q < 0.01 1/nm up to Q < 150 1/nm, with a resolution of 0.16 Angstrom. The computations exploit a modified 3D Fast Fourier Transform (3D-FFT), whose modifications enable the transformations of matrices at least up to 8000^3 voxels in size. Multiple of these modified 3D-FFTs are combined to improve the low-Q behaviour. The resulting curve is compared to a wide-range scattering pattern measured on a polydisperse MOF powder. While computationally intensive, the approach is expected to be useful for simulating scattering from a wide range of realistic, complex structures, from (poly-)crystalline particles to hierarchical, multicomponent structures such as viruses and catalysts.
KW - X-ray
KW - Simulation
KW - 3D Fourier Transform
KW - High resolution
KW - XRD
KW - SAXS
KW - PDF
KW - Total scattering
KW - X-ray scattering
KW - Metal organic framework
KW - Electron density map
KW - FFT
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572067
DO - https://doi.org/10.48550/arXiv.2303.13435
VL - Cornell University
SP - 1
EP - 12
PB - Ithaca, NY
AN - OPUS4-57206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation of the LME Susceptibility of Dual Phase Steel with Different Zinc Coatings
N2 - The application of anti-corrosion coated, high-strength steels in the automotive industry has increased in recent years. In combination with various zinc-based surface coatings, liquid metal embrittlement cracking can be observed in some of these materials. A high-quality, crack-free spot-welded joint is essential to realize the lightweight potential of the materials. In this work, the LME susceptibility of different coatings, which will be determined by the crack length and the occurrence rate, will be investigated using a welding under external load setup. The uncoated specimens did not show any LME. EG, GI and GA showed significantly less LME than ZM coatings. The latter coatings showed much larger crack lengths than the EG, GI and GA coatings. Furthermore, two mechanisms regarding the LME occurrence rate were observed: the occurrence of LME in zinc–magnesium coatings was theorized to be driven by the material properties of the coatings, whereas the occurrence of LME at EG, GI and GA samples was forced mainly by the application of the external tensile load.
In the experimental setup of this work, the materials were exposed to unusually high mechanical loads (up to 80% of their yield strength) to evoke LME cracks.
KW - Widerstandspunktschweißen
KW - Hochfester Stahl
KW - Liquid Metal Embrittlement
KW - Flüssigmetallinduzierte Rissbildung
KW - Zink
KW - AHSS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580428
DO - https://doi.org/10.3390/met13050890
VL - 13
IS - 5
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-58042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Ganose, Alex
A1 - Sahasrabuddhe, Hrushikesh
A1 - Asta, Mark
A1 - Beck, Kevin
A1 - Biswas, Tathagata
A1 - Bonkowski, Alexander
A1 - Bustamante, Joana
A1 - Chen, Xin
A1 - Chiang, Yuan
A1 - Chrzan, Daryl
A1 - Clary, Jacob
A1 - Cohen, Orion
A1 - Ertural, Christina
A1 - George, Janine
A1 - Gallant, Max
A1 - George, Janine
A1 - Gerits, Sophie
A1 - Goodall, Rhys
A1 - Guha, Rishabh
A1 - Hautier, Geoffroy
A1 - Horton, Matthew
A1 - Kaplan, Aaron
A1 - Kingsbury, Ryan
A1 - Kuner, Matthew
A1 - Li, Bryant
A1 - Linn, Xavier
A1 - McDermott, Matthew
A1 - Rohith Srinivaas Mohanakrishnan,
A1 - Naik, Aakash
A1 - Neaton, Jeffrey
A1 - Persson, Kristin
A1 - Petretto, Guido
A1 - Purcell, Thomas
A1 - Ricci, Francesco
A1 - Rich, Benjamin
A1 - Riebesell, Janosh
A1 - Rignanese, Gian-Marco
A1 - Rosen, Andrew
A1 - Scheffler, Matthias
A1 - Schmidt, Jonathan
A1 - Shen, Jimmy-Xuan
A1 - Sobolev, Andrei
A1 - Sundararaman, Ravishankar
A1 - Tezak, Cooper
A1 - Trinquet, Victor
A1 - Varley, Joel
A1 - Vigil-Fowler, Derek
A1 - Wang, Duo
A1 - Waroquiers, David
A1 - Wen, Mingjian
A1 - Yang, Han
A1 - Zheng, Hui
A1 - Zheng, Jiongzhi
A1 - Zhu, Zhuoying
A1 - Jain, Anubhav
T1 - Atomate2: Modular workflows for materials science
N2 - High-throughput density functional theory (DFT) calculations have become a vital element of computational materials science, enabling materials screening, property database generation, and training of “universal” machine learning models. While several software frameworks have emerged to support these computational efforts, new developments such as machine learned force fields have increased demands for more flexible and programmable workflow solutions. This manuscript introduces atomate2, a comprehensive evolution of our original atomate framework, designed to address existing limitations in computational materials research infrastructure. Key features include the support for multiple electronic structure packages and interoperability between them, along with generalizable workflows that can be written in an abstract form irrespective of the DFT package or machine learning force field used within them. Our hope is that atomate2’s improved usability and extensibility can reduce technical barriers for high-throughput research workflows and facilitate the rapid adoption of emerging methods in computational material science.
KW - Automation
KW - DFT
KW - Digitalisation
KW - Materials design
KW - Machine learning
KW - Machine learned interatomic potentials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624487
DO - https://doi.org/10.26434/chemrxiv-2025-tcr5h
SN - 2573-2293
SP - 1
EP - 66
PB - American Chemical Society (ACS)
CY - Washington, D.C.
AN - OPUS4-62448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - Wang, Zhuoqun
A1 - Haak, Viktor
A1 - Olfert, Viktoria
A1 - El-Sari, Bassel
A1 - Hein, David
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - A novel welding schedule for expanding the expulsion-free process window in resistance spot welding of dissimilar joints with ultra-high strength steel
N2 - This study introduces a novel approach to expanding the maximum expulsion-free process window in resistance spot welding (RSW) of dissimilar joints between ultra-high strength steel (UHSS) and mild steel. Quantitative analysis revealed that expulsion is driven by the interaction between nugget growth rate and plastic shell thickness. Based on this finding, the welding schedule was optimized by applying a preheating current to form an initial plastic shell, followed by a ramp-up current profile during the main welding phase. Welding simulations indicated that the ramp-up current slowed nugget growth, improved plastic shell formation, and prevented nugget breakthrough, thereby reducing the risk of expulsion. Experimental validation showed a 19 % increase in maximum expulsion-free heat input, with the nugget diameter increasing by 7.6 % to 8.94 mm compared to the reference welding schedule. Furthermore, even when expulsion occurred beyond the process window, this optimization delayed its occurrence, minimizing its impact on spot weld quality. Finally, the optimized welding schedule also exhibited significant robustness. Despite a 2 mm initial gap disturbance, the maximum expulsionfree heat input increased by 57 %, while the nugget diameter grew by 30 % to 8.92 mm. These results confirm that the proposed approach effectively extends the process window by preventing expulsion and enhances process stability.
KW - Expulsion
KW - Resistance spot welding
KW - Finite element modelling
KW - Preheating
KW - Ultra-high-strength steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626877
DO - https://doi.org/10.1016/j.jmapro.2025.02.009
SN - 2212-4616
VL - 137
SP - 306
EP - 309
PB - Elsevier BV
AN - OPUS4-62687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Zimmermann, Yoel
A1 - Bazgir, Adib
A1 - Al-Feghali, Alexander
A1 - Ansari, Mehrad
A1 - Bocarsly, Joshua
A1 - Brinson, L. Catherine
A1 - Chiang, Yuan
A1 - Circi, Defne
A1 - Chiu, Min-Hsueh
A1 - Daelman, Nathan
A1 - Evans, Matthew L.
A1 - Gangan, Abhijeet S.
A1 - George, Janine
A1 - Harb, Hassan
A1 - Khalighinejad, Ghazal
A1 - Khan, Sartaaj Takrim
A1 - Klawohn, Sascha
A1 - Lederbauer, Magdalena
A1 - Mahjoubi, Soroush
A1 - Mohr, Bernadette
A1 - Moosavi, Seyed Mohamad
A1 - Naik, Aakash
A1 - Ozhan, Aleyna Beste
A1 - Plessers, Dieter
A1 - Roy, Aritra
A1 - Schöppach, Fabian
A1 - Schwaller, Philippe
A1 - Terboven, Carla
A1 - Ueltzen, Katharina
A1 - Wu, Yue
A1 - Zhu, Shang
A1 - Janssen, Jan
A1 - Li, Calvin
A1 - Foster, Ian
A1 - Blaiszik, Ben
T1 - 34 Examples of LLM Applications in Materials Science and Chemistry: Towards Automation, Assistants, Agents, and Accelerated Scientific Discovery
N2 - Large Language Models (LLMs) are reshaping many aspects of materials science and chemistry research, enabling advances in molecular property prediction, materials design, scientific automation, knowledge extraction, and more. Recent developments demonstrate that the latest class of models are able to integrate structured and unstructured data, assist in hypothesis generation, and streamline research workflows. To explore the frontier of LLM capabilities across the research lifecycle, we review applications of LLMs through 34 total projects developed during the second annual Large Language Model Hackathon for Applications in Materials Science and Chemistry, a global hybrid event. These projects spanned seven key research areas: (1) molecular and material property prediction, (2) molecular and material design, (3) automation and novel interfaces, (4) scientific communication and education, (5) research data management and automation, (6) hypothesis generation and evaluation, and (7) knowledge extraction and reasoning from the scientific literature. Collectively, these applications illustrate how LLMs serve as versatile predictive models, platforms for rapid prototyping of domain-specific tools, and much more. In particular, improvements in both open source and proprietary LLM performance through the addition of reasoning, additional training data, and new techniques have expanded effectiveness, particularly in low-data environments and interdisciplinary research. As LLMs continue to improve, their integration into scientific workflows presents both new opportunities and new challenges, requiring ongoing exploration, continued refinement, and further research to address reliability, interpretability, and reproducibility.
KW - Automation
KW - LLM
KW - Machine Learning
KW - Agent
KW - Bonding Analysis
KW - Materials Searches
KW - Finetuning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631720
DO - https://doi.org/10.48550/arXiv.2505.03049
SP - 1
EP - 33
AN - OPUS4-63172
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Jonathan
A1 - Merz, Benjamin
A1 - Poka, Konstantin
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Surface structure analysis using visual high-resolution in situ process monitoring in laser powder bed fusion
N2 - Parameter studies are a common step in selecting process parameters for laser powder bed fusion of metals (PBF-LB/M). Density cubes are commonly used for this purpose. Density cubes manufactured with varied process parameters can exhibit distinguishable surface structures visible to the human eye. The layer-wise process enables such surface structures to be detected during manufacturing. However, industrial visual in situ monitoring systems for PBF-LB/M currently have limited resolution and are incapable of reliably capturing small differences in the surface structures. In this work, a 65 MPixel high-resolution monochrome camera was integrated into an industrial PBF-LB/M machine together with a high-intensity LED (light-emitting diode) bar. Post-exposure images were taken to analyse differences in light reflection of fused areas. It is revealed that the grey-level co-occurrence matrix can be used to quantify the visual surface structure of nickel-based superalloy Inconel®939 density cubes per layer. The properties of the grey-level co-occurrence matrix correlate to the energy input and the resulting porosity of density cubes. Low-energy samples containing lack of fusion flaws show an increased contrast in the grey-level co-occurrence matrix compared to specimens with optimal energy input. The potential of high-resolution images for quality assurance via in situ process monitoring in PBF-LB/M is further discussed.
KW - Additive manufacturing
KW - Powder bed fusion
KW - In situ monitoring
KW - Image processing
KW - High resolution camera
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626685
DO - https://doi.org/10.1007/s40194-025-01955-1
SN - 1878-6669
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-62668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Savitsky, Viktor
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Comparative performance of DIC and optical flow algorithms for displacement and strain analysis in laser beam welding
N2 - The measurement of strain and displacement in the context of the welding process represents a significant challenge. Optical methods, such as digital image correlation (DIC) or optical flow algorithms, have demonstrated their efficacy in robust and reliable data acquisition in harsh environments, including those encountered in welding processes. Concurrently, a trade-off between the accuracy of the measurement and the computational resources required for the associated calculations must be evaluated on a case-by-case basis. The application of filters to initial images represents a technique that serves to enhance the quality and accuracy of the strain and displacement prediction. In the present study, the estimated error of two algorithms, namely the Lucas-Kanade (LK) and the inverse compositional Gauss-Newton (IC-GN), is compared on the basis of both synthetic and real welding images. The displacement field is evaluated for different zones in the laser weld seam with varying contrast performance. Based on the aforementioned results, a strain calculation was conducted for both methods, which yielded comparable results for the LK and IC-GN algorithms.
KW - Laser speckle
KW - DIC
KW - Optical flow
KW - Error estimation
KW - Strain measurement
KW - Laser beam welding
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625919
DO - https://doi.org/10.1016/j.optlaseng.2025.108870
SN - 1873-0302
VL - 187
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-62591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmolke, Tobias
A1 - Brunner-Schwer, Christian
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - On welding of high-strength steels using laser beam welding and resistance spot weld bonding with emphasis on seam leak tightness
N2 - The design of most electric vehicles provides for the positioning of the heavy energy storage units in the underbody of the cars. In addition to crash safety, the battery housing has to meet high requirements for gas tightness. In order to test the use of high-strength steels for this sub-assembly, this paper examines welded joints utilizing resistance spot weld bonding and laser remote welding, with special regard to the gas tightness of the welds. For this purpose, the pressure difference test and helium sniffer leak detection are presented and applied. The combination of both leak test methods has proven ideal in experimental investigations. For laser remote welding, gas-tight seams can be achieved with an inter-sheet gap of 0.1 mm, even if occasionally leaking samples cannot be prevented. Resistance spot welding suits gas-tight joining with both one- and two-component adhesives. Against the background of leak tightness, process fluctuations that lead to weld spatter and defects in the adhesive layer must be prevented with high priority.
KW - Resistance spot weld bonding
KW - Laser welding
KW - Seam leak tightness
KW - High-strength steel
KW - Leak testing
KW - Helium sniffer leak detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624250
DO - https://doi.org/10.3390/jmmp7030116
SN - 2504-4494
VL - 7
IS - 3
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-62425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Liu, Yuanbin
A1 - Morrow, Joe D.
A1 - Ertural, Christina
A1 - Fragapane, Natascia L.
A1 - Gardner, John L. A.
A1 - Naik, Aakash
A1 - Zhou, Yuxing
A1 - George, Janine
A1 - Deringer, Volker L.
T1 - An automated framework for exploring and learning potential-energy surfaces
N2 - Machine learning has become ubiquitous in materials modelling and now routinely enables large-scale atomistic simulations with quantum-mechanical accuracy. However, developing machine-learned interatomic potentials requires high-quality training data, and the manual generation and curation of such data can be a major bottleneck. Here, we introduce an automated framework for the exploration and fitting of potential-energy surfaces, implemented in an openly available software package that we call autoplex ('automatic potential-landscape explorer'). We discuss design choices, particularly the interoperability with existing software architectures, and the ability for the end user to easily use the computational workflows provided. We show wide-ranging capability demonstrations: for the titanium-oxygen system, SiO2, crystalline and liquid water, as well as phase-change memory materials. More generally, our study illustrates how automation can speed up atomistic machine learning -- with a long-term vision of making it a genuine mainstream tool in physics, chemistry, and materials science.
KW - Machine learned interatomic potentials
KW - Ab initio
KW - DFT
KW - Automation
KW - Workflows
KW - Machine learning
KW - Materials design
KW - Materials discovery
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623188
DO - https://doi.org/10.48550/arXiv.2412.16736
SN - 2331-8422
SP - 1
EP - 27
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-62318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Sonntag, Nadja
A1 - Jürgens, M.
A1 - Uhlemann, Patrick
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Datasets for Service-Like Creep-Fatigue Experiments on Grade P92 Steel
N2 - The dataset contains experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress.
Further information on data and data acquisition, analysis, and experimental details are given in “Experimental Data from Service-Like Creep-Fatigue Experiments on Grade P92 Steel”, submitted to Data in Brief. Additional analyses of these datasets, as well as experimental findings and discussions are presented in “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times”, submitted to International Journal of Fatigue.
KW - Creep-fatigue
KW - Stress relaxation
KW - Dwell-Fatigue
KW - Tempered martensite-ferritic steel
PY - 2022
DO - https://doi.org/10.5281/zenodo.7198218
PB - Zenodo
CY - Geneva
AN - OPUS4-55995
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eisenbart, Miriam
A1 - Hanke, Thomas
A1 - Bauer, Felix
A1 - Beygi Nasrabadi, Hossein
A1 - Junghanns, Kurt
A1 - Dziwis, Gordian
A1 - Tikana, Ladji
A1 - Parvez, Ashak Mahmud
A1 - van den Boogaart, Karl Gerald
A1 - Sajjad, Mohsin
A1 - Friedmann, Valerie
A1 - Preußner, Johannes
A1 - Ramakrishnan, Anantha Narayanan
A1 - Klengel, Sandy
A1 - Meyer, Lars‐Peter
A1 - Martin, Michael
A1 - Klotz, Ulrich Ernst
A1 - Skrotzki, Birgit
A1 - Weber, Matthias
T1 - KupferDigital: Ontology‐Based Digital Representation for the Copper Life Cycle
N2 - The copper life cycle comprises numerous stages from the alloy production to the manufacturing and usage of engineered parts until recycling. At each step, valuable data are generated and stored; some are transferred to the subsequent stations. A thorough understanding of the materials’ behavior during manufacturing processes or throughout their product lifetime is highly dependent on a reliable data transfer. If, for example, a failure occurs during the service life, information about the manufacturing route can be of decisive importance for detecting the root cause of the failure. Additionally, the life cycle assessment hinges on the availability of data. Recording and storing interoperable structured data is, therefore, a thriving research field with huge implications for the economic strength of the manufacturing industry. In the KupferDigital project, it is demonstrated how an ontology‐based data space can be utilized not only as an innovative method for storing and providing interoperable life cycle data but also as a means to enable automated data analysis and evaluation, leading to new insights and the creation of new knowledge using semantic data and technologies. This work illustrates how data recorded at different research facilities can be integrated into one single data space, allowing queries across heterogeneous sources.
KW - Copper Alloy
KW - Ontology
KW - Digitalization
KW - Data Space
KW - Semantic Representation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630213
SN - 1527-2648
DO - https://doi.org/10.1002/adem.202401735
VL - 27
IS - 8
SP - 1
EP - 29
PB - Wiley
AN - OPUS4-63021
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Hanke, T.
A1 - Muth, Thilo
A1 - Riedel, Jens
A1 - Schilling, Markus
A1 - Schweizer, C.
A1 - Skrotzki, Birgit
A1 - Todor, A.
A1 - Moreno Torres, Benjami
A1 - Unger, Jörg F.
A1 - Völker, Christoph
A1 - Olbricht, Jürgen
T1 - A Perspective on Digital Knowledge Representation in Materials Science and Engineering
N2 - The amount of data generated worldwide is constantly increasing. These data come from a wide variety of sources and systems, are processed differently, have a multitude of formats, and are stored in an untraceable and unstructured manner, predominantly in natural language in data silos. This problem can be equally applied to the heterogeneous research data from materials science and engineering. In this domain, ways and solutions are increasingly being generated to smartly link material data together with their contextual information in a uniform and well-structured manner on platforms, thus making them discoverable, retrievable, and reusable for research and industry. Ontologies play a key role in this context. They enable the sustainable representation of expert knowledge and the semantically structured filling of databases with computer-processable data triples.
In this perspective article, we present the project initiative Materials-open-Laboratory (Mat-o-Lab) that aims to provide a collaborative environment for domain experts to digitize their research results and processes and make them fit for data-driven materials research and development. The overarching challenge is to generate connection points to further link data from other domains to harness the promised potential of big materials data and harvest new knowledge.
KW - Data infrastructures
KW - Digital representations
KW - Digital workflows
KW - Knowledge graphs
KW - Materials informatics
KW - Ontologies
KW - Vocabulary providers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546729
DO - https://doi.org/10.1002/adem.202101176
SN - 1438-1656
SP - 1
EP - 14
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-54672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Ermittlung von Kitagawa-Takahashi Diagrammen auf der Basis der Schwingbruchmechanik
N2 - Das Kitagawa-Takahashi Diagramm ist ein unverzichtbares Werkszeug zur Auslegung von Bauteilen aus fehlerbehafteten Werkstoffen. Zur Beschreibung des Diagramms werden im Allgemeinen die Modelle nach Kitagawa-Takahashi, El Haddad oder Chapetti verwendet, die sich aber im technisch relevanten Bereich zum Teil deutlich voneinander unterscheiden. Daher ist eine experimentelle Absicherung dieses Bereichs zwingend erforderlich. Im Rahmen dieser Arbeit wurden verschiedene Methoden zur experimentellen Absicherung miteinander verglichen, mit dem Ziel eine einfache und schnelle experimentelle Absicherung des KT-Diagramms zu ermöglichen. Die neue experimentelle Methode hat sich als nützliches Werkzeug zur Validierung von KT-Diagrammen erwiesen. Durch die Erzeugung von Kerben mittels eines Gravierlasers und die Durchführung der Versuche mit Potentialmessung kann das KT-Diagramm eines Werkstoffes schnell und mit wenig Aufwand validiert werden.
T2 - 58. Tagung des Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Stuttgart, Germany
DA - 24.02.2026
KW - Schwingbruchmechanik
KW - Ermüdungsfestigkeit
KW - Kitagawa-Takahashi Diagramm
KW - Gleichstrom-Potentialsonde
PY - 2026
AN - OPUS4-65645
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
T1 - Aluminium High Temperature Fatigue
N2 - The studied aluminium alloy is EN AW-2618A (2618A). It is very widely used for exhaust gas turbo-charger compressor wheels. Due to long operating times, high cycle fatigue (HCF) and material aging under the influence of temperatures up to 230 °C is particularly relevant for the wheels. The wheels are typically milled from round wrought blanks. From such round blanks, different testpieces are extracted and a comprehensive series of HCF tests is conducted at room temperature. The tests investigate the materials fatigue performance in the T61 state for two load-ratios, namely R = -1 and R = 0.1. Additionally, two overaged material states are tested, accounting for the aging process the material undergoes during long operating times at high temperatures. The experimental results are evaluated and compared to each other.
Furthermore, the design process of notched specimens is presented. With the notched specimens, it is aimed to quantify the notch sensitivity of the material. Relating thereto, two potential model parameters for the fatigue lifetime model are introduced.
T2 - FVV Frühjahrstagung 2022
CY - Würzburg, Germany
DA - 31.03.2022
KW - High Cycle Fatigue
KW - Aluminium Alloy
KW - EN AW-2618A
PY - 2022
AN - OPUS4-54886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - Numerical study of additional element transport in wire feed laser beam welding
N2 - The distribution of the alloying elements from the filler wire in laser beam welding plays an important role on the property of the final weld. In this study, the transport phenomena in the wire feed laser beam welding are investigated numerically. A three-dimensional transient heat transfer and fluid flow model coupled with free surface tracing and element transport is developed. A ray-tracing method with local grid refinement algorithm is used to calculate the multiple reflections and Fresnel absorption on the keyhole wall. The filler material flows backward along the lateral side of the weld pool, and subsequently flows forward along the longitudinal plane to bring the additional alloying elements to the forepart of the weld pool. The occurrence of the bulging phenomenon may further prevent the downward transfer of the additional elements to the root of the weld pool. The numerical results show a good agreement with the experimental fusion line and element distribution.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
CY - Online meeting
DA - 07.09.2020
KW - Laser beam welding
KW - Element transport
KW - Filler material
PY - 2020
AN - OPUS4-51568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Skrotzki, Birgit
T1 - Radii of S-phase Al2CuMg in Al-alloy EN AW 2618A after different aging times at 190°C
N2 - The dataset contains data from quantitative microstructural analysis of transmission electron microscopy (TEM) studies of the S-phase (Al2CuMg) radii in Al-alloy EN AW 2618A. The investigated material and the applied methods were described in detail in two publications.
KW - Aluminium alloy
KW - EN AW 2618A a
KW - S-phase
KW - Al2CuMg
KW - Aging
KW - Creep
KW - Radii distribution
KW - TEM
PY - 2022
UR - https://doi.org/10.5281/zenodo.6659461
UR - https://doi.org/10.5281/zenodo.7625259
DO - https://doi.org/10.5281/zenodo.6659460
PB - Zenodo
CY - Geneva
AN - OPUS4-55067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis
A1 - Graf, B.
A1 - Rehmer, Birgit
A1 - Petrat, T.
A1 - Skrotzki, Birgit
A1 - Rethmeier, Michael
T1 - Characterization of Ti-6Al-4V fabricated by multilayer laser powder-based directed energy deposition
N2 - Laser powder-based directed energy deposition (DED-L) is increasingly being used in additive manufacturing (AM). As AM technology, DED-L must consider specific challenges. It must achieve uniform volume growth over hundreds of layers and avoid heat buildup of the deposited material. Herein, Ti–6Al–4V is fabricated using an approach that addresses these challenges and is relevant in terms of transferability to DED–L applications in AM. The assessment of the obtained properties and the discussion of their relationship to the process conditions and resulting microstructure are presented. The quality of the manufacturing process is proven in terms of the reproducibility of properties between individual blanks and with respect to the building height. The characterization demonstrates that excellent mechanical properties are achieved at room temperature and at 400 °C.
KW - AGIL
KW - Laser powder-based directed energy deposition
KW - Tensile properties
KW - Ti-6Al-4V
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542262
DO - https://doi.org/10.1002/adem.202101333
SN - 1438-1656
SN - 1527-2648
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Non-vegan flame-retardant (adjuvants in) biocomposites
N2 - Emanating from developing flame retarded biocomposites, we have proposed renewable natural fibers (including keratin) taken from industrial waste as an authentic sustainable approach. More recently, we have investigated non-vegan flame retardant approaches. This paper loves to give you an insight into our ongoing projects on biogenic industrial wastes like leather, bone meal, and insects. Materials were characterized multi-methodically, flame retardant modes of action quantified, decomposition mechanism proposed, and synergisms explained. Considering the large quantities of leather waste (LW) in industrial-scale production, we underline LW as multifunctional bio-adjuvants. LW enhances the flame retardancy of poly(ethylene-vinyl acetate) (EVA) containing phosphorus flame retardants (P-FR). Products/by-products of the invertebrate and vertebrate farming, respectively, are promising bio-based adjuvants in flame retarded bio-epoxy thermosets. While the addition of bone meal yields the formation of an inorganic shield, protein-based powders from insects provide an intumescent behavior. In combination with a P-FR superior charring and self-extinguishing are obtained.
Acknowledgement: In part of this work was supported by the Volkswagen Foundation grant “Experiment!” No. 97437.
T2 - Fire and Polymers, workshop, ACS Division of Polymer Chemistry
CY - Napa, California, US
DA - 05.06.2022
KW - Fire behaviour
KW - Renewable
KW - Circular economy
KW - Biocomposite
PY - 2022
AN - OPUS4-55025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachtendorf, Volker
T1 - Untersuchung der Witterungsbeständigkeit komplexer Funktionalitäten von Polymerwerkstoffen durch künstliche Bewitterung: Flammschutz
N2 - In den letzten Jahrzehnten wurde die Degradation der polymeren Matrix von flammgeschützten Polymeren eingehend untersucht. Erst in den letzten Jahren jedoch hat sich die Frage der Lebensdauer der Funktionalität des Flammschutzes selbst als wichtige Fragestellung herauskristallisiert, z.B. bei Kabeln. Deshalb sollte diese Fragestellung durch systematisch-variierte künstliche Klima- und Bewitterungstests an flammgeschützten Polymerwerkstoffen untersucht werden
T2 - 50. Jahrestagung der Gesellschaft für Umweltsimulation (GUS)
CY - Online meeting
DA - 23.03.2022
KW - Flammschutz
KW - Witterungsbeständigkeit
KW - Langzeitbeständigkeit
KW - UV
KW - E&E
PY - 2022
AN - OPUS4-54541
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suarez Ocano, Patricia
T1 - Effect of the powder composition on the microstructure and mechanical properties of 316L stainless steel fabricated by laser powder bed fusion
N2 - Additive manufacturing (AM) has seen rapid growth in recent decades, with Laser Powder Bed Fusion (PBF-LB/M) emerging as the leading technique for producing high-density, geometrically complex metal parts. Austenitic stainless steel 316L is one of the most studied alloys for PBF-LB/M due to its excellent strength, ductility, and corrosion resistance [1]. The microstructure formed during PBF-LB/M processing can improve certain mechanical properties compared to conventionally manufactured 316L [2].
However, the current 316L standards allow broad ranges for key alloying elements, particularly Cr and Ni. While such variations have little effect on conventionally produced alloys, emerging evidence shows that they can markedly alter the microstructure and mechanical properties in PBF-LB/316L—even within specification limits [3]. This study investigates through microstructural and thermodynamical assessment, how two powders of nominally standard 316L composition (Alloys A and B) respond to identical PBF-LB/M processing parameters. Despite identical printing conditions, Alloy A exhibited
twice the grain size and five times higher low-angle grain boundary (LAGB) density compared to Alloy B . Conversely, Alloy B showed a significantly higher density of Σ3 twin boundaries, nearly absent in Alloy A. These microstructural differences are attributed primarily to variations in Cr and Ni content in the liquid, which may influence icosahedral short-range ordering (ISRO) mechanism [4]. ISRO potentially facilitates twin boundary formation, ultimately refining grain structure [5]. This work highlights the critical impact of compositional control on final part microstructures and consequent mechanical properties and emphasizes the need to reassess compositional tolerances for AM-specific applications.
T2 - 5th Symposium on Materials and Additive Manufacturing (Additive 2026)
CY - Kassel, Germany
DA - 24.03.2026
KW - Additive manufacturing
KW - 316L stainless steel
KW - Chemical composition
KW - Lcosahedral short-range ordering mechanism
KW - Grain size
PY - 2026
AN - OPUS4-65738
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Assessing the low cycle fatigue behaviour of additively manufactured Ti-6Al-4V: Challenges and first results
N2 - The understanding of process-microstructure-property-performance (PMPP) relationships in additive manufacturing (AM) of metals is highly necessary to achieve wide-spread industrial application and replace conventionally manufactured parts, especially regarding safety-relevant applications. To achieve this understanding, reliable data and knowledge regarding material’s microstructure-property relationships (e.g. the role of defects) is needed, since it represents the base for future more targeted process optimizations and more reliable calculations of performance. However, producing reliable material data and assessing the AM material behaviour is not an easy task: big challenges are e.g. the actual lack of standard testing methods for AM materials and the occasional difficulties in finding one-to-one comparable material data for the conventional counterpart.
This work aims to contribute to end this lack of reliable material data and knowledge for the low cycle fatigue behaviour of the most used titanium alloy in aerospace applications (Ti-6Al-4V). For this purpose, two sets of test specimens were investigated. The first set was manufactured from cylindrical rods produced by an optimized DED-L process and the second was manufactured from a hot formed round bar. The test specimens were cyclically loaded until failure in the low-cycle-fatigue (LCF) regime. The tests were carried out according to ISO 12106 between 0.3 to 1.0 % axial strain amplitude from room temperature up to 400°C. The LCF behaviour is described and compared between materials and with literature values based on cyclic deformation curves and strain-based fatigue life curves. Besides, the parameters of Manson-Coffin-Basquin relationship were calculated. The microstructures (initial and after failure) and fracture surfaces were comparative characterized. Thereby, the focus lied on understanding the role of grain morphology and defects on the failure mechanisms and fatigue lifetimes. For this latter characterization, optical microscopy (OM), scanning electron microscopy (SEM) and micro computed tomography (µCT) were used.
T2 - 4th International Symposium on Fatigue Design and Material Defects
CY - Online meeting
DA - 26.05.2020
KW - Ti-6Al-4V
KW - Additive manufacturing
KW - Low cycle fatigue
KW - Micro computed tomography
KW - Microstructure
PY - 2020
AN - OPUS4-50893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Han, Ying
A1 - Schriever, Sina
A1 - von Hartrott, Philipp
A1 - Rockenhäuser, Christian
A1 - Skrotzki, Birgit
T1 - Dataset on the Creep Properties of EN AW-2618A Aluminum Alloy in the T61 and an overaged condition
N2 - This publication contains comprehensive metadata and test results of constant force creep tests according to DIN EN ISO 204 on the aluminum alloy EN AW-2618A in the T61 condition (8 h/530 °C/quenching in boiling water followed by 28 h/195 °C/air cooling) and in an overaged condition (T61 + 1.000 h/190 °C). The test temperatures cover 160 °C, 180 °C, 190 °C, and 230 °C, and the initial stresses range between 40 MPa and 290 MPa.
KW - Creep
KW - Aging
KW - Overaging
KW - Aluminum alloy
KW - EN AW-2618A
KW - High temperature
PY - 2025
DO - https://doi.org/10.5281/zenodo.15744297
PB - Zenodo
CY - Geneva
AN - OPUS4-63572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zirnstein, Benjamin
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
T1 - Combination of phosphorous flame retardants and aluminum trihydrate in multicomponent EPDM composites
N2 - Ethylene propylene diene monomer (EPDM) Rubbers with the flame retardants tris(2-ethylhexyl)phosphate, ammonium polyphosphate, polyaniline, and aluminum trihydroxide were prepared and analyzed in this study. The homogenous dispersion of the fillers in the rubber matrix was confirmed by scanning electron microscope. To investigate the interplay of the different flame retardants, the flame retardants were varied systematically. The comprehensive study sought combinations of flame retardants that allow high loadings of flame retardants without deterioration of the physical and mechanical properties of the EPDM rubber. The eight EPDM rubbers were investigated via thermogravimetric analysis and pyrolysis gas chromatography coupled with a mass spectrometer (Py GC/MS) to investigate the potential synergistic effects. In the Py-GC/MS experiments, 27 pyrolysis products were identified. Furthermore, UL 94, limiting oxygen index, FMVSS 302, glow wire tests, and cone calorimeter tests were carried out. In the cone calorimeter test the EPDM rubbers R-1AP and R-1/2P achieved an increase in residue at flameout of 76% and a reduction in total heat evolved of about 35%. Furthermore, the compounds R-1AP and R-1/2P achieved a reduction in MARHE to about 150 kW m−1, a reduction of over 50% compared to the unprotected rubber R.
KW - EPDM
KW - Rubber
KW - Aluminum hydroxide (ATH)
KW - Phosphorous flame retardant
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502859
DO - https://doi.org/10.1002/pen.25280
SN - 1548-2634
VL - 60
IS - 2
SP - 267
EP - 280
PB - Wiley
AN - OPUS4-50285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Agudo Jácome, Leonardo
T1 - Low-Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature
N2 - The nickel-base superalloy Inconel 718 (IN718) is one of the most commonly used Ni-based superalloys for high temperature structural applications for its remarkable strength, as well as creep, fatigue, and corrosion resistance up to 650 °C. While IN718 has traditionally been employed as cast or wrought material, it is difficult to machine because of its high strength and toughness. The additive manufacturing of IN718 components made by metal AM has thus gained extensive attention to produce expensive near-net shaped components of high-temperature alloys such as IN718, for it saves material and costs in processing and machining steps. Among all metal additive manufacturing (AM) technologies, laser powder bed fusion (PBF-LB/M) is the most widespread, IN718 being one of the most common alloys produced with it. However, high cooling rates associated to the PBF-LB/M process, hinders the primary strengthening phases γ’’ and γ’ to form, as these cooling rates induce a dislocation cellular substructure, at which walls primary Laves phases bind segregating Nb, Ti and Mo. Many of the therefore needed heat-treatment strategies can then promote Laves-phase transformation into the stable δ phase along the cell and grain boundaries. Laves and δ phases, as well as grain-boundary primary carbides may have adverse effects on mechanical properties. The mostly needle-shaped δ phase was namely found to have a detrimental effect on creep rupture life while no direct effect on LCF fatigue life was evident. In this work room- and high-temperature (650 °C) low-cycle fatigue behavior of PBF-LB/M IN718 is investigated in the four-step heat-treated state and compared to wrought IN718. The microstructure of both materials is characterized across length scales via microscopy methods. The fatigue life at room temperature of the PBF-LB/M IN718 material is slightly lower than that for the wrought material, which is reversed at 650 °C. The cyclic stress response for both materials is marked by cyclic softening that is more pronounced at higher test temperatures. Multiple secondary cracks form at high strain amplitudes, at both room and high temperatures. High testing temperatures enhance specially crack formation at the transitions of regions between elongated grains and columns of stacked grains with ripple patterns in the PBF-LB/M material. Additional to this behavior, pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients.
T2 - EUROMAT 2025
CY - Granada, Spain
DA - 14.09.2025
KW - Additive manufacturing
KW - Low-cycle fatigue
KW - Microstructural characterization
KW - Ni-base superalloy
PY - 2025
AN - OPUS4-64354
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Management of Reference Data of Creep of Ni-Based Superalloys Exemplified for CMSX-6
N2 - The identification of process-structure-property relationships of materials inevitably requires the combination of research data from different measurements. Therefore, the concepts related to FAIR (findable, accessible, interoperable, reusable) data handling, increasingly reported in literature, are particularly important in the materials science and engineering domain. However, they have not yet been integrated into a single, overarching methodological framework, particularly for reference data. Here, we introduce such a framework, which covers data generation, documentation, handling, storage, sharing, data search and discovery, retrieval, and usage. Furthermore, we prototypically implement it using a real dataset with creep data of a single-crystal CMSX-6 Ni-based superalloy. The implementation is traceable and permanently accessible through open repositories. The individual elements considered in the framework ensure the functionality and usability of the data and, thus, the adherence to the FAIR principles. In conjunction with this, we present a definition for reference data of materials. Our definition underlines particularly the importance of a comprehensive documentation, e.g., on material provenance, data processing procedures, and the software and hardware used, including software-specific input parameters, as these details enable data users or independent parties to assess the quality of the datasets and to reuse and reproduce the results. Reference data that is managed according to the proposed framework can be used to advance knowledge in the materials science and engineering domain, e.g., by identifying new process-structure-property relations.
T2 - The 20th International Conference on Strength of Materials
CY - Kyoto, Japan
DA - 02.06.2025
KW - NFDI-MatWerk
KW - Referenzdaten
KW - Data schema
KW - Creep
PY - 2025
AN - OPUS4-63428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ávila Calderón, Luis
A1 - Han, Ying
A1 - Matzak, Kathrin
A1 - Olbricht, Jürgen
A1 - Skrotzki, Birgit
T1 - NFDI-MatWerk/IUC02 data schema for elevated temperature tensile data of Ni-based superalloys
N2 - Strength characteristics, such as proof strength and tensile strength, of metallic materials are usually measured at room temperature. However, for high-temperature materials, the values at operational temperatures are equally important for analyzing the mechanical behavior of components or for designing purposes. Elevated temperature tensile tests (often referred to as hot tensile tests) generally enable the measurement of the same material parameters as those obtained at room temperature. Typically, tensile and proof strength, elongation after fracture, and reduction of area are analyzed, with the focus often being on proof strength.
The attached data schema for elevated temperature tensile tests was developed within the German NFDI-MatWerk initiative (https://nfdi-matwerk.de/). It builds on a previously published creep data schema and follows a reference data methodology that has also been previously outlined.
The presented schema constitutes a structured approach for collecting all relevant information on an elevated temperature tensile test experiment. Overall, this development, as defined in the previously published data schema for creep data, aims to provide a comprehensive hierarchical data description that can be implemented in data management platforms (such as electronic laboratory notebooks), facilitate consistent quality assessment across different users and data providers, and promote the alignment of datasets to the FAIR principles by providing easy interoperability and full reusability.
The presented schema was initially developed for datasets of Ni-based high-temperature alloys. However, thanks to its modular structure, it can also be applied to tensile tests of various metallic and other materials. Although the focus is on elevated temperature tensile testing, the data schema also offers a solid foundation for documenting room temperature tensile tests. In such cases, an adjustment of the requirement profile might be necessary, and categories or entries specific to mechanical testing at elevated temperatures, such as “temperature-measuring system”, “specified temperature”, or “soaking time”, become irrelevant.
Overall, a detailed approach was followed to ensure the collection of all relevant information, including both metadata and test results. This includes, for example, comprehensive descriptions of the material’s manufacturing history and of the laboratory equipment, and basic strength and deformation characteristic values. The resulting data schema aims to support the description and identification of high-quality datasets, which may qualify as reference data of materials. Our current definition of reference data of materials has been published elsewhere. It should be noted, however, that not all research datasets —depending on their origin and purpose— require this full level of detail. Nevertheless, the presented data schema can support data providers in evaluating the completeness and value of their datasets.
This version of the data schema covers elevated temperature tensile tests on both single- and polycrystalline specimen materials. The terminology is aligned with DIN EN ISO 6892-1 and DIN EN ISO 6892-2. It is designed to record the use of temperature measurement using thermocouples and the use of contacting extensometer systems.
The requirement profile refers to the highest quality class of reference data, taken from calibrated instruments, and which shall enable the following usages:
1. Checking one's own elevated temperature tensile test results on nominally similar material
2. Verification of own testing set-up (e.g., by testing the same or a similar material)
3. Using the data as input data for simulations in the context of design or alloy development
KW - NFDI MatWerk
KW - Referenzdaten
KW - Zugversuch
KW - CMSX-6
KW - Datenschema
KW - NFDI MatWerk
KW - CMSX-6
KW - Data schema
KW - Reference data
KW - Tensile test
PY - 2025
UR - https://doi.org/10.5281/zenodo.17846436
DO - https://doi.org/10.5281/zenodo.17846435
PB - Zenodo
CY - Geneva
AN - OPUS4-65190
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Mit Hilfe künstlicher Intelligenz neue Materialien finden
N2 - Dieser Vortrag wurde im Rahmen einer Outreach-Veranstaltung für Schüler*innen gehalten (https://www.hansenberg.de/lernen/hansenberg-summit/summit-2022.html). Er beschreibt, wie wir an der BAM und an anderen Institutionen nach neuen Materialien suchen.
T2 - Hansenberg Summit
CY - Geisenheim, Germany
DA - 09.07.2022
KW - Materialdesign
KW - Materialinformatik
PY - 2022
AN - OPUS4-55408
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, R.
A1 - Osayi, J.
A1 - Kmieciak, S.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Verschleißschutz einer Schneckengeometrie durch funktional gradierte Materialien
N2 - Hochbelastete Stahlbauteile lassen sich durch Auftragen von Kobalt-Chrom Legierungen vor Verschleiß schützen. Die plötzliche Änderung der Materialeigenschaften führt jedoch zu Spannungen und Rissen im Anbindungsbereich. Daraus resultierende Abplatzungen stellen eine Gefahr für die Funktionsfähigkeit der Maschine und damit für Mensch und Umwelt dar. Um die Belastbarkeit der Schutzschicht zu verbessern, kann die Anbindung durch einen gradierten Materialübergang optimiert werden. Diese funktional gradierten Materialien können mittels pulverbasiertem Directed Energy Deposition aufgetragen werden. Die Methodik zum Aufbau und zur Qualitätssicherung solcher Materialien wurde in vorangegangenen Arbeiten für dickwandige Geometrien gezeigt. Für dünnwandige Geometrien ist die Anwendbarkeit bisher unzureichend untersucht worden. Diese Arbeit zeigt am Beispiel einer dünnwandigen gradierten Schneckengeometrie die Einsatzfähigkeit der Methodik. Dafür wird die Gefügestruktur der Gradierung auf Fehler untersucht und der Härteverlauf gemessen. Außerdem wird die relative Dichte anhand eines bereits trainierten neuronalen Netzes vorhergesagt und mit einer Porositätsuntersuchung verglichen.
T2 - 14. Tagung Verschleiß- und Korrosionsschutz von Bauteilen durch Auftragschweißen
CY - Halle a. d. Saale, Germany
DA - 12.06.2024
KW - Directed Enery Deposition
KW - Funktionally Graded Material
KW - Additive Manufacturing
KW - DED
KW - FGM
KW - AM
PY - 2024
SP - 1
EP - 7
PB - SLV Halle
AN - OPUS4-60721
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winkler, Michael
T1 - Automated Repair of Gas Turbine Blades Using DED-Arc
N2 - Gas turbine blades are critical components in aerospace and power generation, often subject to wear, erosion, and fatigue-induced damage. Traditional repair methods are labor-intensive, costly, prone to inconsistencies, and not rapidly adaptable. This work presents an automated approach for repairing gas turbine blade tips using Wire and Arc Directed Energy Deposition (DED-Arc) in combination with a high-precision point to point registration technique of laser line triangulation (LLT) 3D scans. The proposed workflow begins with affixation of the milled down turbine blade to a work piece manipulator using a 3D printed clamping mechanism and a rough alignment of the turbine tip. Subsequently, the turbine blade’s geometry is acquired using a fully integrated 3D laser triangulation sensor, transforming, and aggregating the captured 2D line data into a 3D scan in the working user coordinate system using live feedback data from a finely calibrated industry robot. This point cloud representation of the real-world turbine blade is then used as the target during an advanced point-to-point shape registration technique transforming the digital representation of the repair process containing all relevant tool path and geometry data into the coordinate system of the real-world turbine blade. Afterwards, the turbine tip is then iteratively repaired whereby the turbine tip geometry is divided into differentiated sections, each with its own optimized process parameter set.
A key innovation in this approach is the adaptability of the repair process through a closed-loop monitoring system. After each DED-Arc deposition, a 3D scan is performed to document the deposited geometry, to detect the interaction of the different process parameter sets, to activate an intervention if necessary, and calculate subsequent tool paths based on current geometry data.
The results indicate that the combination of precise 3D scan registration with DED-Arc is a viable solution for the industrial-scale repair of gas turbine blades leading to significant reduction in labor, tooling, process, and time related cost.
T2 - IIW Assembly
CY - Genoa, Italy
DA - 22.06.2025
KW - DED-Arc
KW - Additive Manufacturing
KW - Repair
KW - Turbine Blade
KW - Automation
PY - 2025
AN - OPUS4-63624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Toward prediction and insight of porosity formation in laser welding: A physics-informed deep learning framework
N2 - The laser welding process is an important manufacturing technology for metallic materials. However, its application is often hindered by the occurrence of porosity defects. By far, an accurate prediction of the porosity defects and an insight into its formation mechanism are still challenging due to the highly nonlinear physics involved. In this paper, we propose a physics-informed deep learning (PIDL) framework by utilizing mechanistic modeling and experimental data to predict the porosity level during laser beam welding of aluminum alloys. With a proper selection of the physical variables (features) concerning the solidification, liquid metal flow, keyhole stability, and weld pool geometry, the PIDL model shows great superiority in predicting the porosity ratio, with a reduction of mean square error by 41 %, in comparison with the conventional DL model trained with welding parameters. Furthermore, the selected variables are fused into dimensionless features with explicit physical meanings to improve the interpretability and extendibility of the PIDL model. Based on a well-trained PIDL model, the hierarchical importance of the physical variables/procedures on the porosity formation is for the first time revealed with the help of the Shapley Additive Explanations analysis. The keyhole ratio is identified as the most influential factor in the porosity formation, followed by the downward flow-driven drag force, which offers a valuable guideline for process optimization and porosity minimization.
KW - Laser beam welding
KW - Physics-informed deep learning
KW - Porosity prediction
KW - Feature fusion
KW - Hierarchical importance
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624708
DO - https://doi.org/10.1016/j.actamat.2025.120740
VL - 286
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-62470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Hirthammer, Volker
A1 - Rethmeier, Michael
T1 - Recommendations for an Open Science approach to welding process research data
N2 - The increasing adoption of Open Science principles has been a prevalent topic in the welding science community over the last years. Providing access to welding knowledge in the form of complex and complete datasets in addition to peer-reviewed publications can be identified as an important step to promote knowledge exchange and cooperation. There exist previous efforts on building data models specifically for fusion welding applications; however, a common agreed upon implementation that is used by the community is still lacking. One proven approach in other domains has been the use of an openly accessible and agreed upon file and data format used for archiving and sharing domain knowledge in the form of experimental data. Going into a similar direction, the welding community faces particular practical, technical, and also ideological challenges that are discussed in this paper. Collaboratively building upon previous work with modern tools and platforms, the authors motivate, propose, and outline the use of a common file format specifically tailored to the needs of the welding research community as a complement to other already established Open Science practices. Successfully establishing a culture of openly accessible research data has the potential to significantly stimulate progress in welding research.
KW - Welding
KW - Research data management
KW - Open science
KW - Digitalization
KW - Weldx
KW - Open source
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529332
DO - https://doi.org/10.1007/s40194-021-01151-x
SN - 1878-6669
SN - 0043-2288
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-52933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Karkhin, V.
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Mathematical modeling of the geometrical differences between the weld end crater and the steady-state weld pool
N2 - The geometrical characteristics of the weld end crater are commonly used as a means of validating numerical results in welding simulations.
In this paper, an analytical model is developed for calculating the cooling stage of the welding process after the moving energy source is turned off. Solutions for various combinations of heat sources and heated bodies are found. It is shown that after turning off the Energy source, additional melting of the base material in the longitudinal direction may occur due to the overheated liquid metal. The developed technique is applied to complete-penetration keyhole laser beam welding of 2 mm thick austenitic stainless-steel plate 316L at a Welding speed of 20 mm/s and a laser power of 2.3 kW. The results show a theoretical increase in the weld end crater length of up to 19% compared to the length of the steady-state weld pool. It is found that at the moment of switch off, the weld end crater center, where solidification of the liquid metal ends, is shifted from the heat source axis toward the weld pool tail. The solidification rate and the direction of crystallization of the molten material during the welding process and those in the weld end crater differ significantly. A good agreement between the computational results and the welding experiments is achieved.
KW - Weld end crater
KW - Steady-state weld pool
KW - Mathematical modeling
KW - Solidification
KW - Laser beam welding
PY - 2020
DO - https://doi.org/10.2351/7.0000068
VL - 32
IS - 2
SP - 022024-1
EP - 022024-6
PB - AIP Publishing
AN - OPUS4-50767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
T1 - On the relationship between the bulge effect and the hot cracking formation during deep penetration laser beam welding
N2 - Recent studies have confirmed the widening of the weld pool interface, known as a bulge effect, during deep penetration high power laser beam welding. The link between such geometric particularities of the weld pool shape and the hot cracking phenomena is significant. The present work seeks to extend the level of understanding by investigating their relationship. A coupled multiphysics, multiscale numerical framework is developed, comprising a series of subsequent analyses. The study examines the influences of the bulge on the three most dominant effects causing hot cracking, namely the thermal cycles, the mechanical loading, and the local microstructure. The bulge in the weld pool shape forms approximately in the middle of the plate, thus correlating with the location of hot cracking. It increases the hot cracking susceptibility by enhancing the three dominant effects. The numerical results are backed up by experimental data.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
CY - Online meeting
DA - 07.09.2020
KW - Hot cracking
KW - Bulge effect
KW - Numerical modelling
KW - Laser beam welding
KW - Deep penetration
PY - 2020
AN - OPUS4-51277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Chaurasia, Prashant Kumar
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Tandem-GMAW: advanced pulsed and short cicuiting process mode experimental data
N2 - This dataset consists of raw recordings for 5 Tandem gas metal arc welding experiments (Tandem-GMAW / T-GMAW).
KW - T-GMAW
KW - High power welding
KW - Deposition efficiency
KW - Life Cycle Assessment
PY - 2025
DO - https://doi.org/10.5281/zenodo.17951724
PB - Zenodo
CY - Geneva
AN - OPUS4-65206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaurasia, Prashant Kumar
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - De, Amitava
A1 - Rethmeier, Michael
T1 - Automated in situ monitoring and analysis of process signatures and build profiles during wire arc directed energy deposition
N2 - Wire arc directed energy deposition (DED-Arc) is an emerging metal additive manufacturing process to build near-net shaped metallic parts in a layer-by-layer with minimal material wastage. Automated in situ monitoring and fast-responsive analyses of process signatures and deposit profiles during DED-Arc are in ever demand to print dimensionally consistent parts and reduce post-deposition machining. A comprehensive experimental investigation is presented here involving real-time synchronous measurement of arc current, voltage, and the deposit profile using a novel multi-sensor monitoring framework integrated with the DED-Arc set-up. The recorded current–voltage transients are used to estimate the time-averaged arc power, and energy input in real time for an insight of the influence of wire feed rate and printing travel speed on the deposit characteristics. A unique attempt is made to represent the geometric profiles of the single-track deposits in a generalized mathematical form corresponding to a segmented ellipse, which has exhibited the minimum root-mean-square error of 0.03 mm. The dimensional inconsistency of multi-track deposits is evaluated quantitatively in terms of waviness using build profile monitoring and automated estimation, which is found to increase with an increase in step-over ratio and energy input. For the multi-track mild steel deposits, the suitable range of step-over ratio for the minimum surface waviness is observed to lie between 0.6 and 0.65. Collectively, the proposed framework of synchronized process monitoring and real-time analysis provides a pathway to achieve dimensionally consistent and defect-free parts, and highlights the potential for closed-loop control systems for a wider industrial application of DED-Arc.
KW - Additive Manufacturing
KW - Arc welding
KW - DED-arc
KW - Real-time monitoring and control
KW - Dimensional inconsistency
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642029
DO - https://doi.org/10.1007/s40964-025-01333-9
SN - 2363-9512
SP - 1
EP - 20
PB - Springer Science and Business Media LLC
CY - Cham
AN - OPUS4-64202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Bähring, S.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Quality Prediction in Directed Energy Deposition Using Artificial Neural Networks Based on Process Signals
N2 - The Directed Energy Deposition process is used in a wide range of applications including the repair, coating or modification of existing structures and the additive manufacturing of individual parts. As the process is frequently applied in the aerospace industry, the requirements for quality assurance are extremely high. Therefore, more and more sensor systems are being implemented for process monitoring. To evaluate the generated data, suitable methods must be developed. A solution, in this context, was the application of artificial neural networks (ANNs). This article demonstrates how measurement data can be used as input data for ANNs. The measurement data were generated using a pyrometer, an emission spectrometer, a camera (Charge-Coupled Device) and a laser scanner. First, a concept for the extraction of relevant features from dynamic measurement data series was presented. The developed method was then applied to generate a data set for the
quality prediction of various geometries, including weld beads, coatings and cubes. The results were compared to ANNs trained with process parameters such as laser power, scan speed and powder mass flow. It was shown that the use of measurement data provides additional value. Neural networks trained with measurement data achieve significantly higher prediction accuracy, especially for more complex geometries.
KW - DED
KW - Artificial neural network
KW - Process monitoring
KW - Quality assurance
KW - Data preparation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547039
DO - https://doi.org/10.3390/app12083955
VL - 12
IS - 8
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-54703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling
N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a raytracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized level-set method. The PLIC-based method is discrete, resulting in noncontinuous free surface reconstruction. In the localized level-set method, a continuous free surface is reconstructed, and, thus, the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics.
KW - Laser beam welding
KW - Laser energy distribution
KW - Weld pool dynamics
KW - Ray teacing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562429
DO - https://doi.org/10.2351/7.0000739
SN - 1042-346X
VL - 34
IS - 4
SP - 042023-1
EP - 042023-8
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-56242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Miliūtė, Aistė
A1 - Bustamante, Joana
A1 - Karafiludis, Stephanos
A1 - Zöllner, Moritz
A1 - Eddah, Mustapha
A1 - Emmerling, Franziska
A1 - Mieller, Björn
A1 - George, Janine
A1 - Stawski, Tomasz M.
T1 - Synthesis and phase purity of the negative thermal expansion material ZrV2O7
N2 - Synthesis of pure, homogeneous, and reproducible materials is key for the comprehensive understanding, design, and tailoring of material properties. In this study, we focus on the synthesis of ZrV2O7, a material known for its negative thermal expansion properties. We investigate the influence of solid-state and wet chemistry synthesis methods on the purity and homogeneity of ZrV2O7 samples. Our findings indicate that different synthesis methods significantly impact the material's characteristics. The solid-state reaction provided high-purity material through extended milling time and repeated calcination cycles, while the sol-gel reaction enabled a “near-atomic” level of mixing and, therefore, homogenous phase-pure ZrV2O7. We confirmed purity via X-ray diffraction and Raman spectroscopy, highlighting differences between phase-pure and multiphase ceramics. These analytical techniques allowed us to distinguish subtle differences in the structure of the material. Based on ab initio simulated phonon data, we were able to interpret the Raman spectra and visualise Raman active atom vibrations. We show that phase purity enables the unbiased characterisation of material properties such as negative thermal expansion.
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - XRD
KW - Raman
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624013
DO - https://doi.org/10.1039/d4tc04095c
SN - 2050-7534
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed A.
A1 - Wani, Y. M.
A1 - Schönhals, Andreas
A1 - Nikoubashman, A.
T1 - Coarse-Grained Simulations of Columnar Ionic Liquid Crystals: Comparison with Experiments
N2 - We simulate a homologous series of guanidinium-based columnar ionic liquid crystals (ILCs) using coarse-grained molecular dynamics (MD) simulations with the Martini force field. We systematically vary the length of alkyl side chains, ILC-n (n = 8, 12, 16), and compare our results with previous experimental findings. Experimentally, ILC-8 exhibits a narrow mesophase window and weak columnar order, while ILC-12 and ILC-16 display a broad mesophase window and high columnar order. The MD simulations show that ILC-8 forms a percolated structure, whereas the longer chain analogues self-assemble into columns, with columnar assembly becoming more prominent as the side chain length increases, in qualitative agreement with the experiments. Furthermore, the intercolumnar distance increases monotonically with increasing side chain length and decreases with increasing temperature. Finally, we find that the diffusion coefficient and ionic conductivity decrease substantially with increasing chain length, consistent with experimental observations. We attribute this decrease in mobility to the formation of hexagonally ordered columns, which restrict transport more than percolated networks.
KW - Ionic liquid crystals
PY - 2024
DO - https://doi.org/10.1021/acs.jpcb.4c03041
SN - 1520-6106
SP - 1
EP - 8
PB - ACS
AN - OPUS4-60857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Parametric study of the laser energy absorption in high-power laser beam welding
N2 - Laser energy absorption on the keyhole wall is decisive for the thermodynamic behavior and the resultant weld properties in the high-power laser beam welding process. However, its highly transient nature on a microsecond scale makes the quantitative analysis challenging. In this paper, the influence of the relevant welding parameters on laser energy absorption is studied statistically by utilizing multiphysical modeling, in which the three-dimensional transient keyhole dynamics and thermo-fluid flow are calculated. A dynamic mesh adaption technique and a localized level-set-based ray-tracing method are employed to improve the model accuracy further. The results show that the focus position has a remarkable effect on the time-averaged laser absorption, and in contrast, the laser energy distribution regime is only slightly influenced by the welding speed in the studied parameter range (1.5–3.0 m/min). The absorption ratio of the laser energy on the keyhole front wall decreases with increasing welding speed and increases with upward-moving focus positions. The comparison between the calculated results and the experimental measurements ensures the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 03.11.2024
KW - Laser beam welding
KW - Laser energy absorption
KW - Weld pool
KW - Parametric study
KW - Multiphysics modeling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616070
DO - https://doi.org/10.2351/7.0001537
SN - 1042-346X
VL - 36
IS - 3
SP - 1
EP - 6
PB - AIP Publishing
AN - OPUS4-61607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bevilacqua, Tommaso
A1 - Gumenyuk, Andrey
A1 - Habibi, Niloufar
A1 - Hartwig, Philipp
A1 - Klawonn, Axel
A1 - Lanser, Martin
A1 - Rethmeier, Michael
A1 - Scheunemann, Lisa
A1 - Schröder, Jörg
T1 - Large-scale thermo-mechanical simulation of laser beam welding using high-performance computing: A qualitative reproduction of experimental results
N2 - Laser beam welding (LBW) is a non-contact joining technique that has gained significant importance in modern industrial manufacturing. One potential problem, however, is the formation of solidification cracks, which particularly affects alloys with a pronounced melting range. The aim of the present work is the development of computational methods and software tools to numerically simulate LBW. In order to obtain a sufficiently accurate solution, a large number of finite elements has to be used. Therefore, a highly parallel scalable solver framework, based on the software library PETSc, was used to solve this computationally challenging problem on a high-performance computing architecture. Finally, the experimental results and the numerical simulations are compared. They are found to be in good qualitative agreement, which confirms the validity of the numerical simulations and allows for a better interpretation of the experimentally observed strain distribution.
KW - Laser beam welding
KW - Thermo-mechanical processes
KW - Solidification cracking
KW - High-performance computing
KW - Domain decomposition methods
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652902
DO - https://doi.org/10.1016/j.rineng.2025.108827
SN - 2590-1230
VL - 29
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Phase-field simulation of the dendrite fragmentation by electromagnetic stirring in AA5754 aluminum alloy laser beam welding
N2 - A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding. Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force, without fragmentation, at the characteristic time instants. Both in the early and late stages, the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth, especially in the direction perpendicular to the solidification. The later stage fragmentation has the possibility of breaking one grain into several, which verifies the possibility of grain refinement caused by dendrite fragmentation. The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth. In addition, the cases with different initial nuclear positions were compared. The grain growth in the low-temperature zone can be inhibited by the equiaxed grains' fragmentation at the high-temperature area (179.8 μm² and 14.7 % start at the center, 115.4 μm² and 9.4 % start at the high-temperature corner, 134.3 μm² and 10.9 % start at the low-temperature corner), which is another kind of grain refinement by the dendrite fragmentation. This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’ appearance (179.8 μm² and 14.7 % when virtual grains appear at t = 4.3803 s and t = 4.3803 s, 134.3 μm² and 10.9 % at t = 4.0977 s and t = 3.9564 s, and 115.4 μm² and 9.4 % at t = 3.8151 s and t = 3.5325 s).
KW - Laser beam welding
KW - Electromagnetic
KW - Aluminum alloys
KW - Phase field method
KW - Equiaxed grain
KW - Dendrite fragmentation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656610
DO - https://doi.org/10.1016/j.cwe.2025.100014
SN - 3117-4159
VL - 35
IS - 1
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-65661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical analysis of the effect of an oscillating metal vapor plume on the keyhole and molten pool behavior during deep penetration laser beam welding
N2 - The effect of the oscillating metal vapor plume on the keyhole and molten pool behavior during the laser beam welding of AlMg3 aluminum alloys is investigated by experimental and numerical methods. The real-time height of the metal vapor plume is measured by high-speed camera observation. The obtained experimental results are used to evaluate the additional heating source and laser beam attenuation caused by the scattering and absorption based on the Beer–Lambert theory. Furthermore, the dynamic behavior of the metal vapor plume is incorporated into a 3D transient heat transfer and fluid flow model, coupled with the ray tracing method, for the laser beam welding of the AlMg3 alloy. It is found that additional heating resulting from the scattered and absorbed laser beam energy by the metal vapor plume significantly expands the shape of the molten pool on the top region. Moreover, the oscillating metal vapor plume caused the fluctuation of the high-temperature region in the molten pool. The probability of keyhole collapse at the bottom increases 17% due to the oscillating laser power induced by the laser beam attenuation. The internal interplay between the metal vapor plume, molten pool shape, and keyhole collapse is obtained. The developed model has been validated by experiments, which shows a good agreement.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Oscillating vapor plume
KW - Keyhole collapse
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587978
DO - https://doi.org/10.2351/7.0001094
SN - 1938-1387
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
PB - AIP Publishing
CY - Melville, NY
AN - OPUS4-58797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
A1 - Gook, Sergej
A1 - Biegler, Max
A1 - Gumenyuk, Andrey
T1 - Anwendung einer Kombination aus Laserhybrid- und Unterpulverschweißen zum Fügen dicker Bleche aus Schiffbaustahl EH36
N2 - In diesem Beitrag wird ein Schweißverfahren vorgestellt, mit dem 30 mm dicke Bleche aus Schiffbaustahl EH36 effizient und werkstoffgerecht gefügt werden können. Die wirtschaftlichen Vorteile des Verfahrens ergeben sich aus dem Wegfall der aufwendigen Kantenvorbereitung und der Reduzierung des Schweißzusatzbedarfs. Die Stumpfschweißnähte werden in einer Lagen-/Gegenlage-Technik durch Laserhybridschweißen und Unterpulverschweißen ausgeführt. Dabei erfolgt die Laserhybridschweißung als Einschweißung mit einer Tiefe von etwa 25 mm, während die Unterpulvernaht als zweiter Durchgang auf der gegenüberliegenden Seite des Bauteils mit einer Einschweißtiefe von 8 mm aufgebracht wird. Die Überlappung der beiden Lagen gewährleistet einen geschlossenen Nahtquerschnitt. Dank der partiellen Durchschweißung der Laserhybridnaht entfällt die Notwendigkeit zur Wurzelformierung. Darüber hinaus bietet die Prozesskombination eine höhere Toleranz gegenüber Ungenauigkeiten in der
Kantenvorbereitung, was die Prozesskomplexität reduziert. Der Einsatz dieses robusteren Verfahrens, das weniger von einer präzisen Kantenvorbereitung abhängig ist, erleichtert die Produktionsvorbereitung, minimiert die Fehleranfälligkeit und senkt die Nachbearbeitungskosten. Dies macht das Laserhybridschweißen besonders attraktiv für Anwendungen im Schiffbau.
T2 - 22. Tagung Schweißen in der maritimen Technik und im Ingenieurbau
CY - Hamburg, Germany
DA - 13.05.2025
KW - Laserhybridschweißen
KW - Unterpulverschweißen
KW - Kerbschlagbiegeversuch
PY - 2025
SP - 87
EP - 98
PB - DVS – Deutsche Verband für Schweißen und verwandte Verfahren e. V
AN - OPUS4-63342
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
T1 - Numerical study of the bulging effect in deep penetration laser beam welding
N2 - This article is devoted to the study of the bulging effect in deep penetration laser beam welding. The numerical results of the investigations are based upon experimental results from previous studies to reveal the relationship between the bulging effect and the hot cracking formation, as well as the mixing of alloying elements in the weld pool. The widening of the molten pool in its center area can be observed in full penetration as well as in partial penetration welds on 8 mm and 12 mm thick structural steel plates, respectively. The weld pool shape is extracted from the simulations to evaluate the extent of the necking of the solidification line as well as the bulging phenomena and its influence on the hot cracking phenomena. Relying on an earlier numerical study utilizing a fixed keyhole, simulation models considering a dynamic keyhole are developed thereto. Additionally, the mixing behavior of alloying elements during partial penetration is investigated. The link between the bulge and the studied phenomena is found to be significant.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - Deep penetration laser beam welding
KW - Welding simulation
KW - Solidification cracking
KW - Bulging effect
PY - 2021
AN - OPUS4-52847
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical analysis of the effect of the metal vapor plume on the keyhole and the molten pool behavior during deep penetration laser beam welding
N2 - The effect of the oscillating metal vapor plume on the keyhole and molten pool behavior during the laser beam welding of AlMg3 aluminum alloys is investigated by the experimental and numerical method. The real-time height of the metal vapor plume is measured by high-speed camera observation. The obtained experimental results are used to evaluate the additional heating source and laser beam attenuation caused by the scattering and absorption based on the Beer-Lambert theory. Furthermore, the dynamic behavior of the metal vapor plume is incorporated into a 3D transient heat transfer and fluid flow model, coupled with the ray tracing method, for the laser beam welding of the AlMg3 alloy. It is found that the additional heating resulting from the scattered and absorbed laser beam energy by the metal vapor plume significantly expands the shape of the molten pool on the top region. Moreover, the oscillating metal vapor plume caused the fluctuation of the molten pool shape. The probability of keyhole collapse at the bottom increases significantly to 72% due to the oscillating laser power induced by the laser beam attenuation. The internal interplay between the metal vapor plume, molten pool shape, and the keyhole collapse are obtained. The developed model has been validated by the experiments, which shows a good agreement.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, Illinois, USA
DA - 16.10.2023
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Oscillating vapor plume
KW - Keyhole collapse
PY - 2023
SP - 1
EP - 10
AN - OPUS4-58841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lemke, J.
T1 - Water and gas atomized AISI 316L powder for DED-LB: A comparative study on powder properties and build quality
N2 - Powder properties are considered a key factor in part quality in laser additive manufacturing, although few studies have investigated the effects in directed energy deposition (DED). Water atomized (WA) and gas atomized (GA) powders are frequently used but may result in different part properties due to powder properties. To examine their qualification for DED-LB, this work examines powders and build quality of AISI 316L. Also, examination techniques are compared. The results show that the powder production has no relevant influence on porosity and Archimedian density of built parts. WA powders show good processability in DED-LB, despite unfavorable morphology. In contrast, WA specimen reach only 10% fracture elongation in tensile testing whereas GA-based specimen achieve 30%. Tensile strength of both is above 500 MPa. The reason for the lower mechanical property values can be attributed to defects and oxides. WA powders may provide a cost-effective alternative for DED-LB when mechanical load requirements are not important.
T2 - Lasers in Manufacturing Conference
CY - Munich, Germany
DA - 23.06.2025
KW - DED-LB
KW - Porosity
KW - AISI 316L
KW - Water atomized
KW - Gas atomized
KW - Powder
PY - 2025
AN - OPUS4-65120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bakir, Nasim
T1 - Influence of the weld pool geometry on solidification cracking in partial penetration high power laser beam welding
N2 - Solidification cracking is still a serious problem in laser beam welding, especially in the welding of thick-walled plates. The influence of weld pool geometry on solidification cracking in partial penetration welding of thick plates is investigated within scope of this study. Therefore, a specific experimental setup of steel and quartz glass in butt configuration and on the side with high-speed camera were used to record the weld pool shape. In addition, the influence of laser inclination angle on the weld pool geometry and on solidification crack formation was investigated. The results show a bulge in the weld pool root, which is separated from an upper region by a necking region. This leads to a case where there are three different longitudinal region lengths with different solidification zones. This temporal sequence of solidification strongly promotes the formation of solidification cracks in the weld root.
T2 - LANE 2022: 12th CIRP Conference on Photonic Technologies
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser beam welding
KW - Weld pool shape
KW - Solidification craking
PY - 2022
AN - OPUS4-56395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Maack, Stefan
A1 - Benner, Philipp
A1 - Kröll, Mirco
A1 - Prager, Jens
A1 - Daum, Werner
A1 - Casperson, Ralf
A1 - Heckel, Thomas
A1 - Spaltmann, Dirk
A1 - et al.,
ED - Wahlster, W.
ED - Winterhalter, C.
T1 - Deutsche Normungsroadmap künstliche Intelligenz
T1 - German standardization roadmap on artificial intelligence
N2 - Im Auftrag des Bundesministeriums für Wirtschaft und Klimaschutz haben DIN und DKE im Januar 2022 die Arbeiten an der zweiten Ausgabe der Deutschen Normungsroadmap Künstliche Intelligenz gestartet. In einem breiten Beteiligungsprozess und unter Mitwirkung von mehr als 570 Fachleuten aus Wirtschaft, Wissenschaft, öffentlicher Hand und Zivilgesellschaft wurde damit der strategische Fahrplan für die KI-Normung weiterentwickelt. Koordiniert und begleitet wurden diese Arbeiten von einer hochrangigen Koordinierungsgruppe für KI-Normung und -Konformität.
Mit der Normungsroadmap wird eine Maßnahme der KI-Strategie der Bundesregierung umgesetzt und damit ein wesentlicher Beitrag zur „KI – Made in Germany“ geleistet.
Die Normung ist Teil der KI-Strategie und ein strategisches Instrument zur Stärkung der Innovations- und Wettbewerbsfähigkeit der deutschen und europäischen Wirtschaft. Nicht zuletzt deshalb spielt sie im geplanten europäischen Rechtsrahmen für KI, dem Artificial Intelligence Act, eine besondere Rolle.
N2 - On behalf of the German Federal Ministry of Economic Affairs and Climate Action, DIN and DKE started work on the second edition of the German Standardization Roadmap Artificial Intelligence in January 2022. With the broad participation and involvement of more than 570 experts from industry, science, the public sector and civil society, the strategic Roadmap for AI standardization was thus further developed. This work was coordinated and accompanied by a high-level coordination group for AI standardization and conformity.
The standardization roadmap implements a measure of the German government’s AI Strategy and thus makes a significant contribution to “AI – Made in Germany”.
Standardization is part of the AI Strategy and is a strategic instrument for strengthening the innovation and competitiveness of the German and European economies. Not least for this reason, standardization plays a special role in the planned European legal framework for AI, the Artificial Intelligence Act.
KW - Digitalisierung
KW - Künstliche Intelligenz
KW - Datenwissenschaft
KW - Normung Roadmap
KW - Data science
KW - Artificial intelligence
KW - Standardization roadmap
KW - Digitization
PY - 2022
UR - https://www.din.de/resource/blob/1072988/20bf33d405710a703aa26f81362493bb/ausgabe-2-nrm-ki-data.pdf
UR - https://www.dke.de/de/arbeitsfelder/core-safety/normungsroadmap-ki
SP - 1
EP - 448
PB - Deutsches Institut für Normung (DIN)
CY - Berlin
ET - 2.
AN - OPUS4-56576
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Laskina, Sofya
T1 - Computing the forward and inverse problem of X-ray scattering
N2 - Continuing progress in the field of X-ray scattering methods empowers scientists with new possibilities to capture the most important piece of information about the structure of the sample - its 3D electron density.
Although the first methods appeared almost a century ago, recovering the density structure of a sample is still very problematic. Most avail-able imaging techniques transform a 3D electron density of a realspace structure into the 2D Fourier Transform of the intensity of scattered waves in the reciprocal space. This process causes a loss of information.
Firstly, instead of a 3D sample, a 2D image is created, and secondly, the phase information of the scattered waves is lost. The latter is known as the ”phase problem” and poses a serious obstacle on a way to recover a 3D electron density. In this work, we draw attention to the problem of forward and inverse Small Angle X-Ray Scattering. In the first, forward, part, we rethink the existing pipelines to computationally simulate such scattering experiments. Although there are efficient implementations of fast Fourier transformation, they often have some drawbacks. For instance, to calculate a 3D fast Fourier transform it is required to place its density in the RAM. For high-resolution structures of size > 1024 3 , this becomes very problematic, as the whole density structure requires more than 16 GB of memory.
CUDA solution allows for a very fast and parallelizable implementation of high-resolution data on hundreds of last-generation machines.
Such computations are very pricy and inaccessible for most scientists.
To bypass this limitation, we propose a solution for a split-up 3D fast Fourier transform, which is implemented as a sequence of 2D and 1D operations. We compare our implementation on the simulated 3D shapes and show the result of a proof-of-concept on 4096 3 Metallorganic framework density structure. In the second, inverse problem, we train an invertible neural network, that given scattering data can predict the shape and its parameters. The architecture is built such, that the inverse problem is learned together with the forward process - the Fourier Transformation. We achieved very good results with this architecture, nonetheless, further testing is required, as the current training set only encompasses three simple shapes: sphere, hard sphere and cylinder.
All code to reproduce and analyze the results is available at https: //github.com/sofyalaski/SAXS-simulations.
KW - Machine Learning
KW - SAXS
KW - DFT
PY - 2023
SP - 1
EP - 76
PB - Freie Universität Berlin
CY - Berlin
AN - OPUS4-56798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Amariamir, Sasan
A1 - Benner, Philipp
A1 - George, Janine
T1 - Prediction of materials synthesizability
N2 - In the pursuit of discovering materials with desirable properties, extending the available material libraries is crucial. High-throughput simulations have become an integral part in designing new materials in the past decades. However, there is no straightforward way of distinguishing synthesizable materials from all the proposed candidates. This project focuses on employing AI-driven methods to estimate synthesizability of materials.
Up to now, material scientists and engineers have relied on domain knowledge as well as empirical heuristics to guess the stability and synthesizability of molecules and crystals. The famous Pauling rules of crystal stability are an example of such heuristics. However, after the accelerating material discovery in all the years since Pauling, these rules now fail to account for the stability of most known crystals. A new predictive set of heuristics for crystal stability/synthesizability is unlikely to be uncovered by human perception, given the magnitude and dimensionality of crystallographic data. Hence, a data-driven approach should be proposed to find a predictive model or set of heuristics which differentiate synthesizable crystal structures from the rest. The main challenge of this research problem is the lack of a negative set for classification. Here, there are two classes of data: the positive class which contains synthesizable materials and the negative class which contains materials which are not synthesizable. While the data from the positive class is simply the data of crystals which have been experimentally synthesized, we do not have access to data points which are certainly unsynthesizable. Strictly speaking, if an attempt of synthesizing a crystal fails, it does not necessarily follow that the crystal is not synthesizable. Also, there is no database available which contains the intended crystal structures of unsuccessful synthesis attempts.
This project proposes a semi-supervised learning scheme to predict crystal synthesizability. The ML model is trained on experimental and theoretical crystal data. The initial featurization focuses on local environments which is inspired by the Pauling Rules. The experimental data points are downloaded through the Pymatgen API from the Materials Project database which contains relaxed structures recorded in Inorganic Crystal Structure Database – ICSD. The theoretical data is queried from select databases accessible through the Optimade project’s API.
T2 - MSE Congress 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Synthesizability
KW - PU Learning
KW - Cheminformatics
PY - 2022
AN - OPUS4-56731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials
N2 - A deep insight into the chemistry and nature of individual chemical bonds is essential for understanding materials. Bonding analysis is expected to provide important features for large-scale data analysis and machine learning of material properties. Such information on chemical bonds can be calculated using the LOBSTER (www.cohp.de) software package, which post-processes data from modern density functional theory computations by projecting plane wave-based wave functions onto a local atomic orbital basis. We have performed bonding analysis on 1520 compounds (insulators and semiconductors) using a fully automated workflow combining the VASP and LOBSTER software packages. We then automatically evaluated the data with LobsterPy (https://github.com/jageo/lobsterpy) and provide results as a database. The projected densities of states and bonding indicators are benchmarked on VASP projections and available heuristics, respectively. Lastly, we illustrate the predictive power of bonding descriptors by constructing a machine-learning model for phononic properties, which shows an increase in prediction accuracies by 27 % (mean absolute errors) compared to a benchmark model differing only by not relying on any quantum-chemical bonding features.
T2 - Sommersymposium des Fördervereins Chemieolympiade
CY - Online meeting
DA - 15.04.2023
KW - Automation
KW - Chemical Bonds
KW - DFT
KW - Quantum Chemistry
PY - 2023
AN - OPUS4-57310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Pauw, Brian Richard
A1 - Laskina, Sofya
A1 - Naik, Aakash
A1 - Smales, Glen Jacob
A1 - George, Janine
A1 - Breßler, Ingo
A1 - Benner, Philipp
T1 - Jupyter notebook and VASP calculation details accompanying the manuscript: "Ultima Ratio: Simulating wide-range X-ray scattering and diffraction"
N2 - Summary:
This notebook and associated datasets (including VASP details) accompany a manuscript available on the ArXiv (https://doi.org/10.48550/arXiv.2303.13435) and hopefully soon in a journal as short communication as well. Most of the details needed to understand this notebook are explained in that paper with the same title as above. For convenience, the abstract is repeated here:
Paper abstract:
We demonstrate a strategy for simulating wide-range X-ray scattering patterns, which spans the small- and wide scattering angles as well as the scattering angles typically used for Pair Distribution Function (PDF) analysis. Such simulated patterns can be used to test holistic analysis models, and, since the diffraction intensity is presented coupled to the scattering intensity, may offer a novel pathway for determining the degree of crystallinity.
The "Ultima Ratio" strategy is demonstrated on a 64-nm Metal Organic Framework (MOF) particle, calculated from $Q<0.01$\,$\mathrm{nm}^{-1}$ up to $Q\approx150$\,$\mathrm{nm}^{-1}$, with a resolution of 0.16\,\AA. The computations exploit a modified 3D Fast Fourier Transform (3D-FFT), whose modifications enable the transformations of matrices at least up to $8000^3$ voxels in size. Multiple of these modified 3D-FFTs are combined to improve the low-$Q$ behaviour.
The resulting curve is compared to a wide-range scattering pattern measured on a polydisperse MOF powder.
While computationally intensive, the approach is expected to be useful for simulating scattering from a wide range of realistic, complex structures, from (poly-)crystalline particles to hierarchical, multicomponent structures such as viruses and catalysts.
KW - X-ray
KW - Simulation
KW - Scattering
KW - MOUSE
KW - Nanomaterials
KW - XRD
KW - SAXS
KW - PDF
KW - Total scattering
KW - 3D Fourier transform
KW - High resolution
KW - FFT
PY - 2023
DO - https://doi.org/10.5281/zenodo.7764044
PB - Zenodo
CY - Geneva
AN - OPUS4-57207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pauw, Brian Richard
T1 - "Ultima Ratio": Multi-scale, high-resolution 3D-FFT scattering pattern simulations
N2 - This talk highlights a proof-of-concept that demonstrates the ability to calculate high-resolution Fourier transforms. These can be combined with multi-scale modeling to simulate scattering over a wide range, from small-angle scattering to XRD and PDF.
T2 - Shapespyer/MuSSIC Launch Workshop
CY - Didcot, UK
DA - 20.02.2023
KW - X-ray scattering
KW - Simulation
KW - Fourier Transform
KW - 3D
KW - High resolution
KW - Multi-scale
PY - 2023
AN - OPUS4-57031
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials (JSONS: Part 1)
N2 - This database consists of bonding data computed using Lobster for 1520 solid-state compounds consisting of insulators and semiconductors. It consists of two kinds of json files. Smaller lightweight JSONS consists of summarized bonding information for each of the compounds. The files are named as per ID numbers in the materials project database.
Here we provide also the larger computational data json files for 700 compounds. This files consists of all important LOBSTER computation output files data stored as dictionary.
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7794811
PB - Zenodo
CY - Geneva
AN - OPUS4-57439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials (JSONS: Part 2)
N2 - This database consists of bonding data computed using Lobster for 1520 solid-state compounds consisting of insulators and semiconductors. The files are named as per ID numbers in the materials project database.
Here we provide the larger computational data JSON files for the rest of the 820 compounds. This file consists of all important LOBSTER computation output files data stored as a dictionary.
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7821727
PB - Zenodo
CY - Geneva
AN - OPUS4-57440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 1)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
Refer to README.md file instructions to reproduce the data.
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852082
PB - Zenodo
CY - Geneva
AN - OPUS4-57441
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 3)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852791
PB - Zenodo
CY - Geneva
AN - OPUS4-57443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 4)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852798
PB - Zenodo
CY - Geneva
AN - OPUS4-57444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 5)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852806
PB - Zenodo
CY - Geneva
AN - OPUS4-57445
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 6)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852808
PB - Zenodo
CY - Geneva
AN - OPUS4-57446
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 7)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852820
PB - Zenodo
CY - Geneva
AN - OPUS4-57447
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - Quantum-Chemical Bonding Database (Unprocessed data : Part 8)
N2 - This data is associated with the manuscript "A Quantum-Chemical Bonding Database for Solid-State Materials."
Refer to mpids.txt to see data related to which compounds are available in the tar file. (mp-xxx refer to Materials Project ID)
KW - Bonding analysis
KW - Automation
KW - Materials Informatics
KW - Computational Chemistry
KW - Database
PY - 2023
DO - https://doi.org/10.5281/zenodo.7852823
PB - Zenodo
CY - Geneva
AN - OPUS4-57448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Crossing Scientific Disciplines with Materials Informatics:� From Atoms to Algorithms
N2 - Within this talk, I introduced students from Physics to Materials Informatics. To provide a context for this research, I have introduced the students to BAM and its tasks. I then started to introduce our activity field materials design, including materials acceleration platforms. Then, I explained how simulations speed up the materials searches as parf of materials acceleration platforms.
T2 - jDPG Jena Meeting - Poland exchange
CY - Jena, Germany
DA - 26.02.2026
KW - Automation
KW - Machine Learning
KW - Materials Design
KW - Batteries
KW - Workflows
PY - 2026
AN - OPUS4-65589
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, S.
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Verfahren zum fehlerfreien Laserstrahl-MSG-Hybridschweißen geschlossener Rundnähte
N2 - In diesem Beitrag werden Ergebnisse der Untersuchungen eines Verfahrens zum fehlerfreien Laserstrahl-MSG-Hybridschweißen von geschlossenen Rundnähten vorgestellt. Das Verfahren zielt auf die Vermeidung von Schweißnahtunregelmäßigkeiten im Überlappbereich einer hybridgeschweißten Rundnaht. Eine Strategie der Prozessführung beim Schließen der Rundnaht wurde entwickelt, mit der ein fehlerfreier Überlappbereich durch die Kontrolle der Erstarrungsbedingungen am Schweißnahtende erreicht wird. Die kontrollierte Wärmeführung wird durch eine Anpassung der Parameter von beiden beteiligten Schweißprozessen, dem Laserstrahl sowie dem Metallschutzgas (MSG)-Schweißprozess, realisiert. Experimentelle Untersuchungen wurden an 12 bis 15 mm dicken Rohrabschnitten durchgeführt. Der Einfluss von Prozessparametern wie der Veränderung des Abbildungsmaßstabs und der Defokussierung des Laserstrahls auf die Erstarrungsbedingungen am Ende der Rundnaht wurde untersucht, um eine optimale Strategie zum Herausführen der Prozessenergie zu finden.
Im Rahmen der experimentellen Untersuchungen konnte gezeigt werden, dass eine Defokussierung des Laserstrahls im Bereich zwischen 60 mm und 100 mm über einen kurzen Auslaufbereich der Naht von etwa 15 mm zu einer deutlich besseren Nahtausbildung im Überlappbereich führt. Es konnte eine günstige kelchförmige Schweißnaht ohne eine Tendenz zur Rissbildung erzielt werden. Die Laseroptik mit motorisch angesteuertem Linsensystem ermöglichte dabei eine Vergrößerung des Laserstrahldurchmessers ohne eine Veränderung der Position des MSG-Lichtbogens relativ zur Bauteiloberfläche.
KW - Hybrid welding
KW - Laser beam welding
KW - Pipe manufacturing
KW - As-shielded arc welding
KW - Weld defects
PY - 2021
VL - 73
IS - 3
SP - 116
EP - 121
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-52365
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Neumann, B.
A1 - Gottschalk, G.-F.
A1 - Biegler, M.
A1 - Goecke, S.-F.
A1 - Rethmeier, Michael
T1 - Detektion von Bindefehlern mittels neuronaler Netze bei DED-Arc/M von Aluminium anhand von Echtzeit- Schweißstromquellendaten
N2 - Mit der Anwendung des Schutzgasschweißens für additive Strukturen wird aufbauend auf Machine-Learning-Modellen, welche bereits zum Überwachen beim Verbindungsschweißen erforscht wurden, ein tiefes neuronales Netz (DNN) zum Monitoring beim DED-Arc/M von Aluminium vorgestellt. Ziel des Machine Learning Modells ist das Identifizieren von Bindefehlern in den aufgebauten Volumina mit prozessbegleitend gemessenen Schweißstromquellensignalen als Input. Es werden durch Algorithmen Merkmalsvariablen in der Vorverarbeitung der Daten extrahiert und die Korrelation zwischen den Merkmalsvariablen und den Bindefehlern analysiert. Durch den vorgestellten Algorithmus werden diese automatisiert als Input an ein DNN übergeben. Diese Arbeit untersucht die Genauigkeit der Klassifizierung von verschiedenen DNN-Architekturen mit jeweils 4 verdeckten Schichten. Als Trainings- und Testsatz werden randomisiert extrahierte Merkmale von defektfreien und fehlerhaften Proben verwendet, wobei Bindefehler zum Teil absichtlich provoziert werden. Das entwickelte neuronale Netz erkennt anhand signifikanter Merkmale aus den Strom- und Spannungsdaten Bindefehler mit einer Genauigkeit von ca. 90%.
T2 - 45. Assistentenseminar Füge- und Schweißtechnik
CY - Niederaudorf, Germany
DA - 09.11.2024
KW - DED-Arc/M
KW - Aluminiumschweißen
KW - Prozessüberwachung
KW - Machine Learning
KW - Deep Neural Network
KW - Bindefehler
PY - 2025
SP - 139
EP - 144
PB - DVS Media GmbH
AN - OPUS4-64838
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Horton, Matthew K.
A1 - Huck, Patrick
A1 - Yang, Ruo Xi
A1 - Munro, Jason M.
A1 - Dwaraknath, Shyam
A1 - Ganose, Alex M.
A1 - Kingsbury, Ryan S.
A1 - Wen, Mingjian
A1 - Shen, Jimmy X.
A1 - Mathis, Tyler S.
A1 - Kaplan, Aaron D.
A1 - Berket, Karlo
A1 - Riebesell, Janosh
A1 - George, Janine
A1 - Rosen, Andrew S.
A1 - Spotte-Smith, Evan W. C.
A1 - McDermott, Matthew J.
A1 - Cohen, Orion A.
A1 - Dunn, Alex
A1 - Kuner, Matthew C.
A1 - Rignanese, Gian-Marco
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Griffin, Sinead M.
A1 - Neaton, Jeffrey B.
A1 - Chrzan, Daryl C.
A1 - Asta, Mark
A1 - Hautier, Geoffroy
A1 - Cholia, Shreyas
A1 - Ceder, Gerbrand
A1 - Ong, Shyue Ping
A1 - Jain, Anubhav
A1 - Persson, Kristin A.
T1 - Accelerated data-driven materials science with the Materials Project
N2 - The Materials Project was launched formally in 2011 to drive materials discovery forwards through high-throughput computation and open data. More than a decade later, the Materials Project has become an indispensable tool used by more than 600,000 materials researchers around the world.
This Perspective describes how the Materials Project, as a data platform and a software ecosystem, has helped to shape research in data-driven materials science. We cover how sustainable software and computational Methods have accelerated materials design while becoming more open source and collaborative in nature. Next, we present cases where the Materials Project was used to understand and discover functional materials. We then describe our eforts to meet the needs of an expanding user base, through technical infrastructure updates ranging from data architecture and cloud resources to interactive web applications. Finally, we discuss opportunities to better aid the research community, with the vision that more accessible and easy-to-understand materials data will result in democratized materials knowledge and an increasingly collaborative community.
KW - Databases
KW - Materials Informatics
KW - Materials Design
KW - Automation
KW - Workflows
KW - Accelerated Discovery
PY - 2025
DO - https://doi.org/10.1038/s41563-025-02272-0
SN - 1476-1122
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-63616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
A1 - Putra, Stephen Nugraha
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Pusbatzkies, Pablo
A1 - Rethmeier, Michael
T1 - Elucidation of the Laser Beam Energy Attenuation by the Vapor Plume Formation during High Power Laser Beam Welding
N2 - In high-power laser beam welding, a common phenomenon is the formation of a keyhole caused by the rapid evaporation of the material. Under atmospheric pressure, this evaporation generates a vapor plume that interacts with the laser beam, leading to energy attenuation and scattering of the laser radiation along its path. These interactions affect the stability of the process and the overall weld quality. This study investigates the influence of the vapor plume on the weld pool and keyhole dynamics during high-power laser beam welding of AlMg3 aluminum alloy through experimental and numerical approaches. The primary goal is to identify key vapor plume characteristics, particularly its length fluctuations, and to improve the accuracy of the numerical models. To achieve this, an algorithm was developed for the automated measurement of the vapor plume length using high-speed imaging and advanced data processing techniques. The measured plume length is then used to estimate the additional vapor heating and laser energy attenuation using the Beer–Lambert law. A refined numerical CFD model, incorporating 3D transient heat transfer, fluid flow, and ray tracing, was developed to evaluate the vapor plume’s impact. Results show that already the time-averaged plume length effectively captures its transient influence and aligns well with experimental weld seam geometries. Additionally, energy scattering and absorption caused by the vapor plume led to a wider weld pool at the top surface. The study also shows an increased percentage of keyhole collapses due to the reduced laser power absorption at the keyhole bottom, further highlighting the importance of accurately modeling vapor plume effects.
T2 - International Congress of Applications of Lasers & Electro-Optics 2025
CY - Orlando, USA
DA - 12.10.2025
KW - Laser beam welding
KW - Vapor plume formation
KW - Weld pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2025
SP - 1
EP - 10
AN - OPUS4-64817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bustamante Pineda, Joana Cecibel
T1 - Lattice thermal conductivity on argyrodite compounds Ag8TS6 (T= Si, Ge and Sn): Experimental and full ab initio approach
N2 - Thermoelectric materials offer a promising solution for energy conservation and environmental protection by addressing the significant heat waste in energy production. These innovative materials have the ability to directly convert heat into electricity and vice versa. Here, we have studied the family of Ag8TS6 (T= Sn, Ge, S) by combining experimental and theoretical approaches. We investigated their structural, vibrational and thermodynamic properties employing the Local Orbital Basis Suite Towards Electronic-Structure Reconstruction (LOBSTER), density-functional theory (DFT) and lattice dynamics computations included in the automated workflows in atomate2 software.
These structures exhibit lower group and sound velocities, along with higher Grüneisen parameters, primarily influenced by the vibrations of Ag⁺ ions due to their low bonding interaction. Based on a newly introduced two-channel lattice dynamics model[4] including lifetimes stated from Grüneisen parameters (similar to the approach in the Slack model), we were also able to successfully model lattice thermal conductivity and compare these results with experimental measurements.
Finally, a bonding analysis of all studied compounds was carried out, indicating a similar bonding situation in all our structures. By using bonding analysis and our model for the lattice thermal conductivity calculations, we demonstrate that the bond heterogeneity found in Ag8SnS6, Ag8GeS6, and Ag8SiS6 is closely connected to its low thermal conductivity, dominated mainly by heat transport via a diffusive exchange of thermal energy between phonon modes (diffusons).
T2 - XLVIII International Congress of Theoretical Chemists of Latin Expression
CY - Cartagena, Colombia
DA - 14.07.2025
KW - Grüneisen parameter
KW - LOBSTER
KW - DFT
KW - QHA
PY - 2025
AN - OPUS4-63818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strobl, Domninic
T1 - Reduced order model for temperature field simulation of wire arc additive manufacturing
N2 - Additive manufacturing (AM) has revolutionized the manufacturing industry, offering a new paradigm to produce complex geometries and parts with customized properties. Among the different AM techniques, the wire arc additive manufacturing (WAAM) process has gained significant attention due to its high deposition rate and low equipment cost. However, the process is characterized by a complex thermal history making it challenging to simulate it in real-time for online process control and optimization.
In this context, a reduced order model (ROM) using the proper generalized decomposition (PGD) method [1] is proposed as a powerful tool to overcome the limitations of conventional numerical methods and enable the real-time simulation of the temperature field of WAAM processes. These simulations use a moving heat source leading to a hardly separable parametric problem, which is handled by applying a novel mapping approach [2]. This procedure makes it possible to create a separated representation of the model, which is required to apply the PGD method, allowing a simulation of multiple layers.
In this contribution, a PGD model is derived for the temperature field simulation of the WAAM process. A layer-by-layer simulation in combination with a compression of the PGD modes, without influencing the approximation error, is shown. The compression is an essential step since the modes sum up quickly over the layers and thus a reduction of the number of modes is needed. Furthermore, using an element birth technique leads usually to an update of the mesh or a new mesh in each time step. Though, this is not the case applying the mapping approach, where only a single nonchanging mesh is required to simulate the deposition of a whole layer.
T2 - ECCOMAS Congress 2024
CY - Lisbon, Portugal
DA - 03.06.2024
KW - Reduced Order Model
KW - Proper Generalized Decomposition
KW - Thermal transient problem
KW - Additive manufacturing
PY - 2024
AN - OPUS4-62231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Bauer, Felix
A1 - Tikana, Ladji
A1 - Uhlemann, Patrick
A1 - Thärig, Steffen
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
T1 - KupferDigital mechanical testing datasets
N2 - The KupferDigital project aims to develop digital methods, tools, and data space infrastructures for digitalizing the entire life cycle of copper materials. The mechanical testing process is one of the main chains of such life cycles which generates lots of important testing data about the mechanical properties of the materials and their related materials and testing metadata. To train the digitalization of the mechanical testing process, different kinds of copper alloys were provided for this project, and their mechanical properties were measured by typical methods like Brinell and Vickers hardness and tensile testing. The primary raw testing data as well as the secondary datasets of these tests are provided. The detailed materials specifications, the utilized mechanical testing methods, and provided datasets are described in the content file. The test data files of heterogeneous structures are processed by the KupferDigital digital tools to be converted to standardized machine-readable data files.
KW - Copper alloys
KW - Dataset
KW - Tensile testing
KW - Mechanical testing
KW - Hardness test
PY - 2023
DO - https://doi.org/10.5281/zenodo.7670582
PB - Zenodo
CY - Geneva
AN - OPUS4-57038
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Usmani, Shirin
T1 - Wood treated with nano metal fluorides - relations between composition, size, and durability
N2 - In this study, nanoscopic particles of magnesium Fluoride (MgF2) and calcium fluoride (CaF2) also known as nano metal fluorides (NMFs), were evaluated for their potential to improve wood durability. Even though these fluorides are sparingly soluble, their synthesis in the form of nano-sized particles turns them into promising candidates for wood preservation. Their distinct property of low-water solubility is proposed to maintain long-lasting protection of treated wood by reducing the leaching of fluoride. Analytical methods were used to characterize the synthesized NMFs and their distribution in treated wood specimens. Transmission electron microscopy images showed that these fluoride particles are smaller than 10 nm. In nano metal fluoride (NMF) treated specimens, aggregates of these particles are uniformly distributed in the wood matrix as confirmed with scanning electron microscopy images and their corresponding energy-dispersive X-ray spectroscopy maps. The fluoride aggregates form a protective layer around the tracheid walls and block the bordered pits, thus reducing the possible flow path for water absorption into wood. This is reflected in the reduced swelling and increased hydrophobicity of wood treated with NMFs. The biocidal efficacy of NMFs was tested against brown-rot fungi (Coniophora puteanaand Rhodonia placenta), white-rot fungus (Trametes versicolor), and termites (Coptotermes formosanus). The fungal and termite tests were performed in accordance with the EN 113 (1996) and EN 117 (2012) standards, respectively. Prior to fungal tests, the NMF treated wood specimens were leached according to the EN 84 (1997)standard. Compared to untreated specimens, the NMF treated wood specimens have a higher resistance to decay caused by brown-rot fungi, white-rot fungus, and termites. Although all NMF treatments in wood reduce the mass loss caused by fungal decay, only the combined treatment of MgF2 and CaF2 has efficacy against both brown-rot fungi and white-rot fungus. Similarly, wood treated with the combined NMF formulation is the least susceptible to attack by C. formosanus.It is proposed that combining MgF2 and CaF2changes their overall solubility to promote the release of fluoride ions at the optimal concentration needed for biocidal efficacy against fungi and termites. In this thesis, it was proven that even after leaching, sufficient fluoride was present to protect NMF treated wood from fungal decay. This shows that NMFs are robust enough for above ground contact outdoor applications of wood, where permanent wetness cannot be avoided according to Use Class 3.2, as per the EN 335 (2013) standard. Also, they pose a low risk to human health and the environment because they are sparingly soluble. Since NMFs significantly reduce the decay of wood, the CO2 fixed in it will be retained for longer than in unpreserved wood. Overall, the novel results of this study show the potential of NMFs to increase the service life of building materials made from non-durable wood.
KW - Termites
KW - Nano metal fluorides
KW - Solubility
KW - Wood protection
KW - Fungi
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525108
DO - https://doi.org/10.18452/22553
SP - i
EP - 118
PB - Humboldt-Universität zu Berlin
CY - Berlin
AN - OPUS4-52510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghazanfari, M. R.
A1 - Vittadello, L.
A1 - Al-Sabbagh, Dominik
A1 - Santhosh, A.
A1 - Frankcom, C.
A1 - Fuß, F.
A1 - von Randow, C. A.
A1 - Siemensmeyer, K.
A1 - Vrijmoed, J. C.
A1 - Emmerling, Franziska
A1 - Jerabek, P.
A1 - Irmlau, M.
A1 - Thiele, G.
T1 - Remarkable Infrared Nonlinear Optical, Dielectric, and Strong Diamagnetic Characteristics of Semiconducting K3[BiS3]
N2 - The ternary sulfido bismuthate K3[BiS3] is synthesized in quantitative yields. The material exhibits nonlinear optical properties with strong second harmonic generation properties at arbitrary wavelengths in the infrared spectral range and a notable laser-induced damage threshold of 5.22 GW cm−2 for pulsed laser radiation at a wavelength of 1040 nm, a pulse duration of 180 fs, and a repetition rate of 12.5 kHz. K3[BiS3] indicates semiconductivity with a direct optical band gap of 2.51 eV. Dielectric and impedance characterizations demonstrate κ values in the range of 6−13 at 1 kHz and a high electrical resistivity. A strong diamagnetic behavior with a susceptibility of −2.73 × 10−4 m3 kg−1 at room temperature is observed. These results suggest it is a promising nonlinear optical candidate for the infrared
region. The synergic physical characteristics of K3[BiS3] provide insight into the correlation of optical, electrical, and magnetic properties.
KW - Electrical properties
KW - Insulators
KW - Materials
KW - Nonlinear optics
KW - Quantum mechanics
PY - 2022
DO - https://doi.org/10.1021/acs.jpclett.2c01689
VL - 13
IS - 30
SP - 6987
EP - 6993
PB - ACS Publications
AN - OPUS4-55456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Palmer, Tahlia M.
A1 - Al-Sabbagh, Dominik
A1 - May, Anastasia
A1 - Prinz, Carsten
A1 - Michalik, Stefan
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - Pre‐Activation as a Route for Tuning the Kinetics of Mechanochemical Transformations
N2 - Learning to control reaction kinetics is essential for translating any chemical technology into real‐world application. Based on time‐resolved in situ powder X‐ray diffraction data, we demonstrate the opportunity to tune mechanochemical reaction rates through the pre‐activation of the starting reagents. For three model co‐crystal systems, the pre‐activation of the most stable reagent yields up to a ca 10‐fold increase in the reaction rate, whilst negligible kinetic enhancement is seen when the less stable reagent is pre‐activated. Moreover, we demonstrate how the polymorphic outcome of mechano‐co‐crystallization is also sensitive to pre‐activation of the starting material. Our results suggest that reproducibility of mechanochemical processes requires detailed understanding over the origin and history of reagent powders, whilst providing a new conceptual framework to design and control mechanochemical reactions.
KW - Mechanochemistry
KW - In situ synthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649409
DO - https://doi.org/10.1002/anie.202516632
SN - 1433-7851
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-64940
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winterkorn, R.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Vorteile und Herausforderungen dynamischer Parameterstudien beim Wire Arc Additive Manufacturing von Al-Mg-Si-Legierungen
N2 - Der Einsatz von Aluminiumlegierungen als Konstruktionswerkstoff hat in den letzten Jahren stetig zugenommen. Insbesondere höherfeste Aluminiumlegierungen, wie die Vertreter der 6000’er Aluminiumgruppe, rücken Aufgrund ihres hervorragenden Festigkeits- / Gewichtsverhältnisses immer mehr in den Fokus.
Vertreter dieser Aluminiumklasse, die als Hauptlegierungselemente Magnesium und Silizium beinhalten, weisen neben der bei allen Aluminiumlegierungen präsenten Affinität zur Porenbildung zusätzlich eine ausgeprägte Heißrissanfälligkeit auf. Die additive Verarbeitung von Al-Mg-Si-Legierungen mittels MSG Verfahren gestaltet sich daher herausfordernd.
Neben der Schweißeignung ist die geometrische Gestalt der Schweißraupe für die additive Fertigung von entscheidender Bedeutung. Spurbreite und Spurhöhe sind maßgebliche Größen, die bei der Pfadgenerierung im Hinblick auf Endkonturnähe und der Vermeidung von Ungänzen, Poren und Bildefehlern zu beachten sind.
Dieser Beitrag zeigt am Beispiel des Wire Arc Additive Manufacturing von Al-Mg-Si-Legierungen einen Ansatz, mit dem es möglich ist, zeit- und kostenintensive vollfaktorielle Parameterstudien zum Erhalt von Spurgeometrie und Schweißqualität durch dynamische Parameterstudien zu ersetzen.
T2 - 41. Assistentenseminar Fügetechnik
CY - Magdeburg, Germany
DA - 02.09.2020
KW - WAAM
PY - 2021
SN - 978-3-96144-141-9
VL - 370
SP - 1
EP - 10
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-52902
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
T1 - How experimental and computational methods allow us to design negative thermal expansion materials
N2 - Combined experimental and computational methods allow comprehensive understanding, design, and tailoring of material properties. We focus on a wellknown negative thermal expansion (NTE) material, zirconium vanadate (ZrV2O7), and address synthesis, characterisation and validation of results with computational simulations. Experimental and computational X-ray diffraction and Raman spectroscopy data highlighted differences between phase-pure and multiphase ceramics. These techniques allowed us to distinguish subtle differences in the structure of the material. Based on ab initio simulated phonon data, unaffected by impurities or instrumental errors, we could interpret the Raman spectra and visualise Raman active atom vibrations. These computational models allowed better insight and further experimental improvement while high-quality experimental data granted the validation and improvement of computational simulation strategy.
T2 - SALSA Make and Measure 2024
CY - Berlin, Germany
DA - 11.09.2024
KW - NTE
KW - Sol-gel
KW - Ab initio
KW - Raman
KW - XRD
PY - 2024
AN - OPUS4-61358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Towards the determination of real process temperatures in the LMD process my multispectral thermography
N2 - Due to the rapid thermal cycles involved in additive manufacturing of metals, high internal stresses and peculiar microstructures occur, which influence the parts mechanical properties. To systematically examine their formation, in-process measurements of the temperature are needed. Since the part emissivity is strongly inhomogeneous and rapidly changing in the process, the applicability of thermography for the determination of thermodynamic temperatures is limited. Measuring the thermal radiation in different wavelengths simultaneously, temperature and emissivity can be separated. Here, we present results of a preliminary study using multispectral thermography to obtain real temperatures and emissivities in directed energy deposition (DED) processes.
T2 - Thermosense: Thermal Infrared Applications XLIII
CY - Online meeting
DA - 12.04.2021
KW - Additive Manufacturing
KW - Process monitoring
KW - Multispectral thermography
KW - Laser metal deposition
KW - TES
KW - LMD
KW - Temperature emissivity separation
PY - 2021
DO - https://doi.org/10.1117/12.2587881
AN - OPUS4-52515
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
T1 - LMD coatings as filler material for laser beam welded 30 mm thick plates
N2 - The development of high energy laser sources enables single-pass welds of thick plates up to 30 mm, but often additional materials are needed to influence the properties of the weld seams. However, the homogenous distribution of filler materials in form of e.g. electrodes is only possible up to 7 mm while the elements are only traceable up to a depth of 14 mm. To overcome this problem a two-step process is used where first the edges of the weld partners are coated with the filler material by laser metal deposition (LMD) and afterwards are welded by laser beam. Single-pass welds with electromagnetic weld pool support of 30 mm thick S355 J2+N-plates with austenitic AISI 316L-coatings were investigated as well as the influence of the coatings to the penetration depth of the laser beam without electromagnetic weld pool support in double-sided joints. The weld seams were tested by X-ray inspection and cross sections.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
CY - Online meeting
DA - 07.09.2020
KW - Penetration depth
KW - Laser metal deposition (LMD)
KW - Laser beam welding
KW - Filler material distribution
PY - 2020
AN - OPUS4-51276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
T1 - Werkstoffsichere Dickblechschweißung und KI - Ressourceneffizienz für die Energiewende
N2 - Die Energiewende erfordert sichere und beanspruchungsgerechte Schweißverbindungen für Windenergieanlagen, Wasserstoff-Pipelines und Speicher. Hochfeste Stähle ermöglichen leichtere Strukturen und reduzieren den Materialverbrauch, was zu einer ressourceneffizienten Fertigung mit geringeren CO₂-Emissionen führt. Das Projekt fokussiert auf KI-gestützte Fertigungs- und Reparaturstrategien, insbesondere beim Unterpulverschweißen, um fehlerfreie Verbindungen und Kaltrissvermeidung sicherzustellen. Ergänzend werden Prüf- und Bewertungskonzepte für die H₂-Readiness sowie Normungsgrundlagen entwickelt, um die Ergebnisse in Richtlinien und Regelwerke wie DIN, DVS und DVGW zu integrieren.
T2 - Mitgliederversammlung 2025 der Forschungsvereinigung Stahlanwendung e. V.
CY - Essen, Germany
DA - 17.12.2025
KW - Werkstoffsicherheit
KW - Kaltrissvermeidung
KW - H₂-Readiness
KW - KI-gestützte Fertigung
KW - Prozessüberwachung
KW - Normung und Regelwerke
KW - Ressourceneffizienz
KW - Prüf- und Bewertungskonzepte
KW - Hochfeste Stähle
KW - Schweißtechnische Reparatur
PY - 2025
AN - OPUS4-65244
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Fateri, M.
A1 - Al-Sabbagh, Dominik
A1 - Günster, Jens
T1 - Investigation of the sintering and melting of JSC-2A lunar regolith simulant
N2 - Future lunar exploration can benefit greatly from In-Situ Resource Utilization. Accordingly, the in-Situ Resource Utilization approach highlights the need for detailed analysis of lunar regolith. In this study, JSC-2A Simulant was studied regarding its sintering and melting behaviour using Differential Thermal Analysis under ambient and inert conditions. The minerals at the crystalline peaks were determined using X-Ray Diffraction analysis.
Moreover, melting droplet shape and wetting behaviour of pressed regolith samples of different particle size distributions were studied by Hot Stage Microscopy technique. Hot Stage Microscopy experiments were performed at different heating rates under ambient conditions. Bloating effects within the solidified samples were then qualitatively examined by X-ray tomography. Lastly, the optimization of processing strategies for the Additive Manufacturing of lunar regolith is discussed.
KW - Lunar regolith
KW - Sintering
KW - Melting
KW - Hot stage microscopy
PY - 2020
DO - https://doi.org/10.1016/j.ceramint.2020.02.212
VL - 46
IS - 9
SP - 14097
EP - 14104
PB - Elsevier Ltd.
AN - OPUS4-50869
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernges, T.
A1 - Hanus, R.
A1 - Wankmiller, B.
A1 - Imasato, K.
A1 - Lin, S.
A1 - Ghidiu, M.
A1 - Gerlitz, M.
A1 - Peterlechner, M.
A1 - Graham, S.
A1 - Hautier, G.
A1 - Pei, Y.
A1 - Hansen, M. R.
A1 - Wilde, G.
A1 - Snyder, G. J.
A1 - George, Janine
A1 - Agne, M T.
A1 - Zeier, W. G.
T1 - Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity
N2 - Next-generation thermal management requires the development of low lattice thermal conductivity materials, as observed in ionic conductors. For example, thermoelectric efficiency is increased when thermal conductivity is decreased. Detrimentally, high ionic conductivity leads to thermoelectric device degradation. Battery safety and design also require an understanding of thermal transport in ionic conductors. Ion mobility, structural complexity, and anharmonicity have been used to explain the thermal transport properties of ionic conductors. However, thermal and ionic transport are rarely discussed in direct comparison. Herein, the ionic conductivity of Ag+ argyrodites is found to change by orders of magnitude without altering the thermal conductivity. Thermal conductivity measurements and two-channel lattice dynamics modeling reveal that the majority of Ag+ vibrations have a non-propagating diffuson-like character, similar to amorphous materials. It is found that high ionic mobility is not a requirement for diffuson-mediated transport. Instead, the same bonding and structural traits that can lead to fast ionic conduction also lead to diffuson-mediated transport. Bridging the fields of solid-state ionics and thermal transport, it is proposed that a vibrational perspective can lead to new design strategies for functional ionic conducting materials. As a first step, the authors relate the so-called Meyer-Neldel behavior in ionic conductors to phonon occupations.
KW - Diffusons
KW - DFT
KW - Phonons
KW - Thermoelectrics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547140
DO - https://doi.org/10.1002/aenm.202200717
SN - 1614-6832
VL - 12
IS - 22
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-54714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Study on the transition behavior of the bulging effect during deep penetration laser beam welding
N2 - The present work is devoted to the study of the transition behavior of the recently confirmed widening of the weld pool, known as the bulging effect, during high-power deep penetration laser beam welding of thick unalloyed steel sheets. A three-dimensional transient multi-physics numerical model is developed, allowing for the prediction of the bulge formation and the study of its temporal behavior. The model is generalized to account automatically for the transition from partial to complete penetration. Several experimental measurements and observations, such as drilling period, weld pool length, temperature, efficiency, and metallographic cross-sections are used to verify the model and assure the plausibility of the numerical results. The analysis of the calculated temperature and velocity distributions, as well as the evolution of the keyhole geometry, shows that the formation of a bulging region strongly depends on the penetration depth of the weld. Based on the numerical results, the bulge is found to occur transiently, having its transition from a slight bulge to a fully developed bulging between penetration depths of 6 mm and 9 mm, respectively.
KW - Laser beam welding
KW - Deep penetration
KW - Bulge formation
KW - Numerical modeling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545067
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2021.122171
VL - 184
SP - 122171
PB - Elsevier Ltd.
AN - OPUS4-54506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
A1 - Petretto, G.
A1 - Naik, Aakash
A1 - Esters, M.
A1 - Jackson, A. J.
A1 - Nelson, R.
A1 - Dronskowski, R.
A1 - Rignanese, G.-M.
A1 - Hautier, G.
T1 - Automated bonding analysis with crystal orbital Hamilton populuations
N2 - Automated bonding analysis software has been developed based on Crystal Orbital Hamilton Populations to facilitate high-throughput bonding analysis and machine-learning of bonding features. This work presents the software and discusses its applications to simple and complex materials such as GaN, NaCl, the oxynitrides XTaO2N (X=Ca, Ba, Sr) and Yb14Mn1Sb11.
KW - Chemical bonds
KW - Automation
KW - High-throughput
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551641
DO - https://doi.org/10.1002/cplu.202200123
SN - 2192-6506
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arnold, M.
A1 - Katzmann, J.
A1 - Naik, Aakash
A1 - Görne, A. L.
A1 - Härtling, Thomas
A1 - George, Janine
A1 - Schuster, C.
T1 - Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: Evidence for and DFT simulation of a radiation-induced phase
N2 - A recent approach to measure electron radiation doses in the kGy range is the use of phosphors with an irradiation dose-dependent luminescence decay time. However, the applicability of the previously investigated material NaYF4:Yb3+,Er3+ is limited as it shows pronounced fading. Therefore, in this work, a modified SrF2 synthesis is presented that results in SrF2 nanoparticles codoped with Yb and either Er, Hm, or Tm. To assess their suitability as dosimeter material, dose response, as well as its degree of fading over 50 up to 140 days after irradiation were measured. Fading rates as small as 5% in SrF2:Er,Yb and 4% in SrF2:Ho,Yb were derived, which are comparable to established dosimeter materials. A combination of spectroscopy, diffraction and DFT calculations was used to elucidate the effect of irradiation, pointing towards the formation of a secondary phase of Yb2+ that we predict could be Yb2OF2. This irreversible formation of a secondary phase is considered to be the explanation for the low fading behavior in SrF2-based phosphors compared to NaYF4:Yb, Er, a highly attractive feature for electron beam dosimetry.
KW - DFT
KW - Structure prediction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554115
DO - https://doi.org/10.1039/D2TC01773C
SN - 2050-7526
VL - 10
IS - 32
SP - 11579
EP - 11587
PB - RSC
CY - London
AN - OPUS4-55411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Study on Duplex Stainless Steel Powder Compositions for the Coating of thick Plates of Laser Beam Welding
N2 - Duplex stainless steels combine the positive properties of its two phases, austenite and ferrite. Due to its good corrosion resistance, high tensile strength, and good ductility, it has multiple applications. But laser beam welding of duplex steels changes the balanced phase distribution in favor of ferrite. This results in a higher vulnerability to corrosion and a lower ductility. Herein, different powder combinations consisting of duplex and nickel for coating layers by laser metal deposition (LMD) are investigated. Afterward, laser tracks are welded, and the temperature cycles are measured. The ferrite content of the tracks is analyzed by feritscope, metallographic analysis, and electron backscatter diffraction. The goal is the development of a powder mixture allowing for a duplex microstructure in a two-step process, where first the edges of the weld partners are coated with the powder mixture by LMD and second those edges are laser beam welded. The powder mixture identified by the pretests is tested in the two-step process and analyzed by metallographic analysis, energy-dispersive X-ray spectroscopy, and
Vickers hardness tests. The resulting weld seams show a balanced duplex microstructure with a homogenous nickel distribution and a hardness of the weld seam similar to the base material.
KW - Duplex AISI 2205
KW - Laser metal deposition
KW - Laser beam welding
KW - Nickel
KW - Stainless steels
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547024
DO - https://doi.org/10.1002/adem.202101327
SN - 1438-1656
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54702
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mosquera Feijoo, Maria
A1 - Oder, Gabriele
A1 - Saliwan Neumann, Romeo
A1 - Buchheim, Michaela
A1 - Kranzmann, Axel
A1 - Olbricht, Jürgen
T1 - Impact of Sample Geometry and Surface Finish on VM12‑SHC Ferritic–Martensitic Steel Under Cyclic Steam Atmosphere Operating Conditions
N2 - The steam side oxidation of ferritic–martensitic VM12-SHC steel was investigated under thermo-cyclic conditions in water steam at 620/320 °C and 30 bar with a focus on assessing the influence of pre-oxidation time, specimen geometry and surface finish. The specimens were pre-oxidized under isothermal conditions in water steam at 620 °C and 30 bar for 500 h or 1500 h. After pre-oxidation treatment, all specimens were subjected up to 258 thermal cycles. Three different geometries—rectangular coupons, U-shaped ring segments and ring samples—were investigated to evaluate the influence of open/closed shape, and flat/curved surface on corrosion rate. At the same time, two types of surface finish were considered: “as received” and “ground.” The formation of a protective scale by pre-oxidation was investigated. EBSD and ESMA analyses revealed that the Cr-content of the alloy appeared to be insufficient for obtaining a protective oxide scale under studied conditions, at the same time the anayses confirmed that initial oxidation depends on presence of minor alloying elements as Si and Mn, strong oxide formers which can alter the kinetics and morphology of the corrosion reaction. Moreover, rectangular coupons with small wall thickness and flat surface exhibited the highest corrosion rate, while “ground” curved samples showed only local oxidation. This indicates that for same pre-oxidation time, oxidation kinetics is controlled by curvature.
KW - Cyclic steam oxidation
KW - 12%Cr steel
KW - Specimen geometry
KW - Surface treatments
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551808
DO - https://doi.org/10.1007/s11085-022-10114-6
SN - 0030-770X
SP - 1
EP - 18
PB - Springer
AN - OPUS4-55180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geisen, O.
A1 - Müller, V.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Integrated weld preparation designs for the joining of L‑PBF and conventional components via TIG welding
N2 - size limitations and high production costs of L-PBF make it competitive for smaller, highly complex components, while the less complex elements of an assembly are manufactured conventionally. This leads to scenarios that use L-PBF only where it’s beneficial, and it require an integration and joining to form the final product. For example, L-PBF combustion swirlers are welded onto cast parts to produce combustion systems for stationary gas turbines. Today, the welding process requires complex welding fixtures and tack welds to ensure the correct alignment and positioning of the parts for repeatable weld results. In this paper, L-PBF and milled weld preparations are presented as a way to simplify the Tungsten inert gas (TIG) welding of rotationally symmetrical geometries using integrated features for alignment and fixation. Pipe specimens with the proposed designs are manufactured in Inconel 625 using L-PBF and milling. The pipe assembly is tested and TIG welding is performed for validation. 3D scans of the pipes before and after welding are evaluated, and the weld quality is examined via metallography and computed tomography (CT) scans. All welds produced in this study passed the highest evaluation group B according to DIN 5817. Thanks to good component alignment, safe handling, and a stable welding process, the developed designs eliminate the need for part-specific fixtures, simplify the process chain, and increase the process reliability. The results are applicable to a wide range of components with similar requirements.
KW - L-PBF
KW - AM feature integration
KW - TIG welding
KW - Integrated alignment features
KW - Pipe weld preparation
KW - Dissimilar joints
KW - Inconel 625
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547042
DO - https://doi.org/10.1007/s40964-021-00221-2
SN - 2363-9512
SP - 1
EP - 11
PB - Springer
AN - OPUS4-54704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Hybrid laser‑arc welding of laser‑ and plasma‑cut 20‑mm‑thick structural steels
N2 - It is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could
be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively.
Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.
KW - Hybrid laser-arc welding
KW - Thick-walled steel
KW - Edge quality
KW - Gap bridgeability
KW - Laser cutting
KW - Plasma cutting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552013
DO - https://doi.org/10.1007/s40194-022-01255-y
SN - 0043-2288
VL - 66
SP - 507
EP - 514
PB - Springer
AN - OPUS4-55201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - George, Janine
A1 - Naik, Aakash
A1 - Ueltzen, Katharina
T1 - Reflections from the 2024 Large Language Model (LLM) Hackathon for Applications in Materials Science and Chemistry
N2 - Here, we present the outcomes from the second Large Language Model (LLM) Hackathon for Applications in Materials Science and Chemistry, which engaged participants across global hybrid locations, resulting in 34 team submissions. The submissions spanned seven key application areas and demonstrated the diverse utility of LLMs for applications in (1) molecular and material property prediction; (2) molecular and material design; (3) automation and novel interfaces; (4) scientific communication and education; (5) research data management and automation; (6) hypothesis generation and evaluation; and (7) knowledge extraction and reasoning from scientific literature. Each team submission is presented in a summary table with links to the code and as brief papers in the appendix. Beyond team results, we discuss the hackathon event and its hybrid format, which included physical hubs in Toronto, Montreal, San Francisco, Berlin, Lausanne, and Tokyo, alongside a global online hub to enable local and virtual collaboration. Overall, the event highlighted significant improvements in LLM capabilities since the previous year's hackathon, suggesting continued expansion of LLMs for applications in materials science and chemistry research. These outcomes demonstrate the dual utility of LLMs as both multipurpose models for diverse machine learning tasks and platforms for rapid prototyping custom applications in scientific research.
KW - Large Language Models
KW - Materials Design
KW - Materials Properties
KW - Phonons
KW - Bonding Analysis
KW - Machine Learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622113
DO - https://doi.org/10.48550/arXiv.2411.15221
SP - 1
EP - 98
AN - OPUS4-62211
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - El-Sari, Bassel
A1 - Olfert, Viktoria
A1 - Wang, Zhuoqun
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - Expulsion prevention in resistance spot welding of dissimilar joints with ultra-high strength steel: An analysis of the mechanism and effect of preheating current
N2 - The widespread adoption of ultra-high strength steels, due to their high bulk resistivity, intensifies expulsion issues in resistance spot welding (RSW), deteriorating both the spot weld and surface quality. This study presents a novel approach to prevent expulsion by employing a preheating current. Through characteristic analysis of joint formation under critical welding current, the importance of plastic material encapsulation around the weld nugget (plastic shell) at high temperatures in preventing expulsion is highlighted. To evaluate the effect of preheating on the plastic shell and understand its mechanism in expulsion prevention, a two-dimensional welding simulation model for dissimilar ultra-high strength steel joints was established. The results showed that optimal preheating enhances the thickness of the plastic shell, improving its ability to encapsulate the weld nugget during the primary welding phase, thereby diminishing expulsion risks. Experimental validation confirmed that by employing the optimal preheating current, the maximum nugget diameter was enhanced to 9.42 mm, marking an increase of 13.4 % and extending the weldable current range by 27.5 %. Under quasi-static cross-tensile loading, joints with preheating demonstrated a 7.9 % enhancement in maximum load-bearing capacity compared to joints without preheating, showing a reproducible and complete pull-out failure mode within the heat-affected zone. This study offers a prevention method based on underlying mechanisms, providing a new perspective for future research on welding parameter optimization with the aim of expulsion prevention.
KW - Resistance spot welding
KW - Finite element modelling
KW - Preheating
KW - Weldable current range
KW - Ultra-high strength steel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621719
DO - https://doi.org/10.1016/j.jmapro.2024.06.034
VL - 124
SP - 489
EP - 502
PB - Elsevier Ltd.
AN - OPUS4-62171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Uhlmann, Eckart
A1 - Polte, Julian
A1 - Fasselt, Janek Maria
A1 - Müller, Vinzenz
A1 - Klötzer-Freese, Christian
A1 - Kleba-Ehrhardt, Rafael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - A Comparative Evaluation of Powder Characteristics of Recycled Material from Bronze Grinding Chips for Additive Manufacturing
N2 - In the manufacturing process of ship propellers, large quantities of grinding chips are generated. These grinding chips result from the finishing of the blade surfaces after the primary casting process of the propeller. The aim of this study was to investigate and compare different preparation processes used to produce chip powders with sufficient powder quality for the additive manufacturing process of directed energy deposition. The preparation of the samples was performed through different sieving, milling and re-melting processes. For the characterization of the prepared samples, powder analysis according to relevant industry standards was carried out. It was found that the re-melting processes result in superior powder quality for additive manufacturing in terms of particle size, morphology, and flowability. For some characteristics, the powder exhibits even better properties than those of commercial powders. Furthermore, the powder properties of the milled samples demonstrate a promising potential for u
KW - Grinding chips
KW - Comminution
KW - Aluminium bronze
KW - Additive manufacturing
KW - Recycling
KW - Sustainability
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621696
DO - https://doi.org/10.3390/ma17143396
VL - 17
IS - 14
SP - 1
EP - 15
PB - MDPI AG
AN - OPUS4-62169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - Sowada, Matthias
A1 - Olfert, Viktoria
A1 - Seitz, Georg
A1 - Schreiber, Vincent
A1 - Heitmann, Marcel
A1 - Hein, David
A1 - Biegler, Max
A1 - Jüttner, Sven
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - Influence of liquid metal embrittlement on the failure behavior of dissimilar spot welds with advanced high-strength steel: A component study
N2 - This study investigates the effects of liquid metal embrittlement (LME) cracks on the mechanical performance of resistance spot-welded joints in zinc-coated advanced high-strength steel (AHSS) at the component level. To this end, a novel component-level test specimen featuring a hat and L-shaped profile was developed to identify
critical failure points under three-point bending loads. Load-bearing capacity tests were subsequently conducted under both quasi-static and impact loading conditions, specifically targeting LME cracks with an average depth reaching 63.6% of the sheet thickness. By monitoring the surface strain of spot welds affected by LME cracks, the study visualizes stress concentration effects at the crack tips and traces the propagation of these cracks into the base material, which ultimately leads to material tearing and joint failure. The findings reveal that the effect of LME cracks in reducing load-bearing capacity is more pronounced under impact loading than under quasi-static
loading, highlighting a previously underexplored aspect of LME behavior under impact loading. Specifically, the peak load decreased by 3.9% and 10.8%, while energy absorption declined by 52.2% and 78.3% under quasistatic and impact loading, respectively.
KW - Liquid metal embrittlement
KW - Resistance spot welding
KW - Impact loading
KW - Crack propagation
KW - Advanced high-strength steel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621727
DO - https://doi.org/10.1016/j.jmrt.2024.11.166
VL - 33
SP - 8321
EP - 8328
PB - Elsevier B.V.
AN - OPUS4-62172
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghosh, Sheuly
A1 - Ueltzen, Katharina
A1 - George, Janine
A1 - Neugebauer, Jörg
A1 - Körmann, Fritz
T1 - Chemical ordering and magnetism in face-centered cubic CrCoNi alloy
N2 - AbstractThe impact of magnetism on chemical ordering in face-centered cubic CrCoNi medium entropy alloy is studied by a combination of ab initio simulations, machine learning potentials, and Monte Carlo simulations. Large magnetic energies are revealed for some mixed L12/L10 type ordered configurations, which are rooted in strong nearest-neighbor magnetic exchange interactions and chemical bonding among the constituent elements. There is a delicate interplay between magnetism and stability of MoPt2 and L12/L10 type of order, which may explain opposing experimental and theoretical findings.
KW - Chemically complex materials
KW - Alloys
KW - Magnetism
KW - Bonding analysis
KW - Machine learning
KW - Machine-learned interatomic potentials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623114
DO - https://doi.org/10.1038/s41524-024-01439-8
SN - 2057-3960
VL - 10
IS - 1
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-62311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, Julius
A1 - Beret, Alexander
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam
N2 - Additive manufacturing is becoming increasingly important for industrial production. In this context, directed energy deposition processes are in demand to achieve high deposition rates. In addition to the well-known laser-based processes, the electron beam has also reached industrial market maturity. The wire electron beam additive manufacturing offers advantages in the processing of copper materials, for example. In the literature, the higher energy efficiency and the resulting improvement in the carbon footprint of the electron beam are highlighted. However, there is a lack of practical studies with measurement data to quantify the potential of the technology. In this work, a comparative life cycle assessment between wire electron beam additive manufacturing (DED-EB) and laser powder additive manufacturing (DED-LB) is carried out. This involves determining the resources for manufacturing, producing a test component using both processes, and measuring the entire energy consumption. The environmental impact is then estimated using the factors global warming potential (GWP100), photochemical ozone creation potential (POCP), acidification potential (AP), and eutrophication potential (EP). It can be seen that wire electron beam additive manufacturing is characterized by a significantly lower energy requirement. In addition, the use of wire ensures greater resource efficiency, which leads to overall better life cycle assessment results.
KW - Life cycle assessment (LCA)
KW - Additive manufacturing
KW - Directed energy deposition
KW - Wire electron beam additive manufacturing
KW - Copper alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621705
DO - https://doi.org/10.1007/s40194-024-01856-9
SP - 3169
EP - 3176
PB - Springer Science and Business Media LLC
AN - OPUS4-62170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Amariamir, Sasan
A1 - George, Janine
A1 - Benner, Philipp
T1 - SynCoTrain: A Dual Classifier PU-learning Framework for Synthesizability Prediction
N2 - Material discovery is a cornerstone of modern science, driving advancements in diverse disciplines from biomedical technology to climate solutions. Predicting synthesizability, a critical factor in realizing novel materials, remains a complex challenge due to the limitations of traditional heuristics and thermodynamic proxies. While stability metrics such as formation energy offer partial insights, they fail to account for kinetic factors and technological constraints that influence synthesis outcomes. These challenges are further compounded by the scarcity of negative data, as failed synthesis attempts are often unpublished or context-specific.
We present SynCoTrain, a semi-supervised machine learning model designed to predict the synthesizability of materials. SynCoTrain employs a co-training framework leveraging two complementary graph convolutional neural networks: SchNet and ALIGNN. By iteratively exchanging predictions between classifiers, SynCoTrain mitigates model bias and enhances generalizability. Our approach uses Positive and Unlabeled (PU) Learning to address the absence of explicit negative data, iteratively refining predictions through collaborative learning.
The model demonstrates robust performance, achieving high recall on internal and leave-out test sets. By focusing on oxide crystals, a well-characterized material family with extensive experimental data, we establish SynCoTrain as a reliable tool for predicting synthesizability while balancing dataset variability and computational efficiency. This work highlights the potential of co-training to advance high-throughput materials discovery and generative research, offering a scalable solution to the challenge of synthesizability prediction.
KW - Materials Design
KW - Materials Discovery
KW - Synthesizability
KW - Machine Learning
KW - Cotraining
KW - New Materials
KW - Materials Acceleration Platforms
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622104
DO - https://doi.org/10.48550/arXiv.2411.12011
SP - 1
EP - 39
AN - OPUS4-62210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemke, Josefine
A1 - Höfemann, Matthias
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Process strategies for optimizing the cooling behaviour of laser-welded Tailor Welded Blanks made of advanced high strength steels (AHSS)
N2 - AHSS with 1000 MPa tensile strength show promising properties for the use in Tailor Welded Blanks (TWBs) to locally strengthen car body parts. Challenges in laser beam welding of the sheets are hardness-drops and -peaks in the heat-affected zone (HAZ) and weld, which cause risks during cold-forming. This happens due to rapid cooling caused by laser welding. A numerical approach aiming for slower cooling rates in the weld region is presented in this article. Laser welded sheets served as reference for setting up a process simulation. Models for pre-heating and a coaxial setup with power split were set up. A correlation between cooling-rate and hardness in the joining zone was established and applied to the modelled strategy. Splitting the power led to a slightly narrower weld seam and experimental pre-heating of the sheets to 600 °C could lower total seam hardening. It achieved a homogenization of the fusion zone.
KW - AHSS
KW - Laser welding
KW - Tailor Welded Blanks
KW - Hardness
KW - FEM
KW - HAZ
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622324
DO - https://doi.org/10.1016/j.procir.2024.08.176
VL - 124
SP - 570
EP - 573
PB - Elsevier B.V.
AN - OPUS4-62232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Putra, Stephen Nugraha
A1 - Meng, Xiangmeng
A1 - Yang, Fan
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical study on the temperature characteristic of material absorptivity and its significance in high-power laser beam welding
N2 - The absorptivity of metallic materials plays an important role in high-power laser beam welding. It affects the amount of absorbed laser power leading to the heating and melting of the surfaces to be joined and is highly dependent on the temperature. Nonetheless, this key characteristic is often ignored in numerical simulations and an empirical parameter determined by trial-and-error approaches is rather implemented to calibrate the results. In the present work, the temperature dependence of laser absorption is included in a three-dimensional multiphase numerical model considering the coupled fluid flow and heat transfer. The calculated laser absorption is determined by the temperature-dependent material properties, laser characteristics, and incident angle of the laser beam. It is found that the temperature dependence of the laser absorption is crucial for accurately determining the keyhole and weld pool geometries, which is validated by experimental measurements using 304 austenitic steel.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Temperature dependent absorption
KW - Weld pool
KW - Keyhole dynamics
KW - Numerical modelling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616146
DO - https://doi.org/10.1016/j.procir.2024.08.179
VL - 124
SP - 585
EP - 589
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-61614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lima, G. T. S.
A1 - Silvestro, L.
A1 - Durlo Tambara, Luís Urbano
A1 - Cheriaf, M.
A1 - Rocha, J. C.
T1 - Autonomous Self-Healing Agents in Cementitious Materials: Parameters and Impacts on Mortar Properties
N2 - The concept of self-healing materials and the development of encapsulated curing agents represent a cutting-edge approach to enhancing the longevity and reducing the maintenance costs of cementitious structures. This systematic literature review aims to shed light on the parameters involved in the autonomous self-healing of cementitious materials, utilizing various encapsulated healing agents such as pellets, granules, and capsules. This review also identifies and selects studies that offer additional insights into the efficacy of the self-healing process in cementitious materials and the influence of these specific encapsulated healing agents on the physical mechanical properties of mortars. This comprehensive approach provides a deep understanding of the interplay between self-healing and the physical–mechanical properties of mortars containing these encapsulated healing agents. The main findings indicate that the cement-to-sand ratio, characteristics of fine aggregates, and encapsulation methods significantly impact crack control, self-healing efficiency, and properties of mortar in both fresh and hardened states. The content of encapsulated healing agents within the cementitious matrix affects both the initial workability or flow and subsequent mechanical properties. While pellets coated with PVA film typically reduce workability in the fresh state and compressive strength, capsules coated with Portland cement and sodium silicate mitigate these effects and improve crack sealing in fresh and hardened states without compromising the self-healing capacity of cracks. The three-point flexural test has emerged as the preferred method for a pre-crack assessment over 28 days, with variations depending on the type of healing agent used. As noted in the literature, water has been identified as the optimal environment for autonomous healing. These findings underscore the potential of encapsulation techniques to enhance self-healing capabilities through the controlled release of agents within the cementitious matrix, thereby advancing the research on and development of intelligent construction materials and increasing the durability of cement-based structures.
KW - Self-healing cementitious composite
KW - Encapsulated curing agents
KW - Pellets
KW - Granules
KW - Capsules
KW - Physical–mechanical properties
KW - Autonomous self-healing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611860
DO - https://doi.org/10.3390/buildings14072000
SN - 2075-5309
VL - 14
IS - 7
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-61186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, Christina
A1 - Szymoniak, Paulina
A1 - Lohstroh, W.
A1 - Juranyi, F.
A1 - Zamponi, M.
A1 - Frick, B.
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Complex molecular dynamics of symmetric model discotic liquid crystals: Comparison of Hexakis(hepta-alkanoyloxy)triphenylene (HOT6) with Hexakis(hexa-alkyloxy)triphenylene (HAT6)
N2 - This study investigates the complex molecular dynamics of discotic liquid crystals (DLCs) by comparing two structurally similar compounds: Hexakis(hepta-alkanoyloxy)triphenylene (HOT6) and Hexakis(hexa-alkyloxy)triphenylene (HAT6) having the same triphenyl core and the same length of the alkyl side chain. The difference of both materials is that the alkyl chain is linked by an oxygen bridge to the triphenylene core for HAT6 and by a ester group for HOT6. Using a combination of broadband dielectric spectroscopy, differential scanning calorimetry, X-ray scattering, and neutron scattering techniques, the research explores the glass transition phenomena and relaxation processes in these materials. HOT6, featuring ester linkages, exhibits distinct dynamic behavior compared to HAT6, including two separate glass transitions indicated by the 1- and 2-relaxation found by dielectric spectroscopy which are assigned to the glassy dynamics of the alkyl side chain in the intercolumnar space and that of the columns, respectively. The study reveals that the ester group in HOT6 leads to increased molecular rigidity and altered packing in the intercolumnar space, as evidenced by X-ray scattering and the vibrational density of states. Neutron scattering confirms localized methyl group rotations and a further relaxation process which relates to the -relaxation revealed by dielectric spectroscopy. The findings contribute to a deeper understanding of glassy dynamics in partially ordered systems and highlight the influence of molecular architecture on relaxation behavior in DLCs.
KW - Discotic Liquid Crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655171
DO - https://doi.org/10.1039/d5sm01247c
SN - 1744-6848
SP - 1
EP - 17
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pérez Blanes, H.
A1 - Ghiasi, Pouria
A1 - Sandkühler, J.
A1 - Yesilcicek, Yasemin
A1 - Pentzien, Simone
A1 - Conradi, Andrea
A1 - Prinz, Carsten
A1 - Al-Sabbagh, Dominik
A1 - Thünemann, Andreas
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation
N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts.
KW - Metals and Alloys
KW - Surfaces
KW - Biomaterials
KW - Ceramics and Composites
KW - Coatings and Films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588218
DO - https://doi.org/10.1016/j.jmrt.2023.05.143
SN - 2238-7854
VL - 24
SP - 9434
EP - 9440
PB - Elsevier B.V.
AN - OPUS4-58821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tambara, R. F.
A1 - Durlo Tambara, Luís Urbano
A1 - Venquiaruto, S. D.
A1 - Pereira da Costa, F. B.
T1 - Evaluation of the mechanical performance and capillary absorption of concretes with incorporation of crystallizing admixtures and subjected to damage at early ages
T1 - Avaliação do desempenho mecânico e absorção capilar de concretos com incorporação de aditivos cristalizante submetidos a danos nas primeiras idades
N2 - This study assessed the self-healing phenomenon in the mechanical properties and capillary absorption of structural concretes. Two crystalline powder additives were evaluated, dosed according to the manufacturers’ recommendations. Crystalline additives increase the density of the C-S-H gel and form insoluble crystals, effectively blocking fissures. Three concrete mixes were produced: a reference mix, additive-X with 0.8%, and additive-Y with 2.0%, relative to the mass of cement. 75% of the rupture load was applied at 3- and 14-days to induce microfissures for comparison with the reference mix. Subsequently, self-healing was assessed at 28- and 76-days. The property of axial compressive strength was determined at 28-days, revealing that crystalline additives contributed to an average increase of 12% in this property. While the age of loading did not significantly impact axial compressive strength, there were significant variations among the types of additives studied, as indicated by ANOVA. Water absorption properties through capillarity were evaluated at 28- and 76-days, showing an average reduction of 42% in water absorption due to the use of crystalline additives. In conclusion, the inclusion of crystalline additives positively contributed to the self-healing of the studied concretes, suggesting a partial recovery of microfissures.
N2 - Esta pesquisa avaliou o fenômeno de autocicatrização nas propriedades mecânicas e absorção capilar de concretos estruturais. Foram avaliados dois aditivos cristalizantes em pó, dosados de acordo com o teor recomendado pelos fabricantes. Aditivos cristalizantes aumentam a densidade do gel C-S-H e formam cristais insolúveis, bloqueando fissuras. Três traços de concreto foram produzidos: referência, aditivo-X com 0,8% e aditivo-Y com 2,0% em relação a massa do cimento. Aplicou-se 75% da carga de ruptura aos 3- e 14-dias para gerar microfissuras e comparar com a referência. Posteriormente, a autocicatrização foi avaliada aos 28- e 76-dias. A propriedade de resistência à compressão axial foi determinada aos 28-dias, revelando que os aditivos cristalizantes contribuíram para um aumento médio de 12% desta propriedade. A idade do carregamento dos concretos não apresentou um impacto significativo na resistência à compressão axial, mas apontou resultados significativos entre os tipos de aditivos estudados, conforme ANOVA. As propriedades de absorção de água por capilaridade foram avaliadas aos 28- e 76-dias, indicando uma redução de absorção de água média de 42% devido ao uso dos aditivos cristalizantes. Em conclusão, a incorporação dos aditivos cristalizantes contribuiu de maneira positiva para a autocicatrização dos concretos estudados, indicando uma recuperação parcial das microfissuras.
KW - Self-healing
KW - Crystalline admixture
KW - Concrete
KW - Cracks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599140
DO - https://doi.org/10.1590/1517-7076-RMAT-2023-0355
SN - 1517-7076
VL - 29
IS - 1
SP - 1
EP - 20
CY - Rio de Janeiro
AN - OPUS4-59914
LA - por
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Starkholm, A.
A1 - Al-Sabbagh, Dominik
A1 - Sarisozen, S
A1 - von Reppert, A
A1 - Rössle, M
A1 - Ostermann, Markus
A1 - Unger, E
A1 - Emmerling, Franziska
A1 - Kloo, L
A1 - Svensson, P
A1 - Lang, F
A1 - Maslyanchuk, O.
T1 - Green Fabrication of Sulfonium-Containing Bismuth Materials for High-Sensitivity X-Ray Detection
N2 - Organic–inorganic hybrid materials based on lead and bismuth have recently been proposed as novel X- and gamma-ray detectors for medical imaging, non-destructive testing, and security, due to their high atomic numbers and facile preparation compared to traditional materials like amorphous selenium and Cd(Zn)Te. However, challenges related to device operation, excessively high dark currents, and long-term stability have delayed commercialization. Here, two novel semiconductors incorporating stable sulfonium cations are presented, [(CH3CH2)3S]6Bi8I30 and [(CH3CH2)3S]AgBiI5, synthesized via solvent-free ball milling and fabricated into dense polycrystalline pellets using cold isostatic compression, two techniques that can easily be upscaled, for X-ray detection application. The fabricated detectors exhibit exceptional sensitivities (14 100–15 190 µC Gyair−1 cm−2) and low detection limits (90 nGyair s−1 for [(CH3CH2)3S]6Bi8I30 and 78 nGyair s−1 for [(CH3CH2)3S]AgBiI5), far surpassing current commercial detectors. Notably, they maintain performance after 9 months of ambient storage. The findings highlight [(CH3CH2)3S]6Bi8I30 and [(CH3CH2)3S]AgBiI5 as scalable, cost-effective and highly stable alternatives to traditional semiconductor materials, offering great potential as X-ray detectors in medical and security applications.
KW - Mechanochemistry
KW - X-ray detectors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630306
DO - https://doi.org/10.1002/adma.202418626
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-63030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
T1 - Prediction of porosity formation in high power laser beam welding using physics informed machine learning framework
N2 - The applications of the high-power laser beam welding process are often hindered by the occurrence of the porosity defect. However, an accurate prediction and an insight of the porosity formation are still challenging due to the highly nonlinear physics involved in the dynamic weld pool and keyhole behaviours. In this paper, the effects of relevant physical variables related to the porosity defect are evaluated by utilizing mechanistic modelling and experimental data within a physics-informed machine learning (PIML) framework. With a proper selection of the physical variables (features) in the aspects of keyhole stability, liquid metal flow and weld pool geometry, which correspondingly describes the bubble formation, bubble movement and bubble capture by the solidification front, the PIML shows great superiority in predicting the porosity ratio in the laser welding of aluminium in comparison with conventional ML model using welding parameters. The Shapley Additive Explanations analysis is employed to provide a hierarchical importance of the variables on the defect formation.
T2 - 77th IIW Annual Assembly and International Conference
CY - Rhodes, Greece
DA - 07.07.2024
KW - Laser beam welding
KW - Machine learning
KW - Porosity
KW - Modelling
PY - 2024
AN - OPUS4-61610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX file format for arc welding research data
N2 - Scientific welding data covers a wide range of physical domains and timescales and are measured using various different sensors. Complex and highly specialized experimental setups at different welding institutes complicate the exchange of welding research data further. The project aims to simplify the exchange and quality assurance of scientific welding data by establishing a common open source file format.
T2 - QPTDat Workshop OpenScience
CY - Eggenstein-Leopoldshafen, Germany
DA - 23.01.2020
KW - Welding
KW - Research data management
KW - Open science
KW - Open data
KW - Digitalization
PY - 2020
AN - OPUS4-50677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Willms, Thomas
T1 - Beware the artifact: Generation of ellagic acid and related species during atmospheric solid analysis probe (ASAP) measurements of iron gall inks and tannins in the negative ionization mode
N2 - A detailed comparative analysis of the results of atmospheric solid analysis probe (ASAP) mass spectrometry of inks, tannins, and gallic acid (GA) in the negative ionization mode was performed. Results obtained for tannin by ASAP have been compared with those obtained with electrospray ionization (ESI). Apart from the GA ion, measurements frequently also yielded anions corresponding to association products and condensation products. At zero collision energy, pure GA gave a dimeric adduct (m/z 339); the formation of ions at m/z 303 and 304 was favored by increased temperatures and collision energies. In the case of inks, the subsequent dehydrogenation of such species to ellagic acid (EA) (m/z 301) was attributed to the oxidative effect of the iron III ion. On the basis of the results, a modification of the “standard ink protocol” has been suggested. Furthermore, several yet non‐described breakdown products and radical ion species of GA and EA ions were identified.
KW - Ink research
KW - ASAP
KW - Ellagic acid
KW - Gallic acid
KW - Metacyclophane
KW - Tannic acid
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659252
DO - https://doi.org/10.1002/jms.70045
SN - 1076-5174
VL - 61
IS - 4
SP - 1
EP - 20
PB - Wiley
CY - Chichester
AN - OPUS4-65925
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Design of representative specimens for the characterization of the fatigue properties of metallic components fabricated by PBF-LB/M
N2 - The process-structure-property-performance relationship is a fundamental paradigm in metal additive manufacturing (AM). The knowledge of how process parameters and post-process treatments influence the material properties and therefore the structural integrity of additively manufactured metallic components is of paramount importance. With respect to this, one of the unsolved problems related to the unique AM process is the reliability of witness samples for part qualification. Focusing on the Laser Powder Bed Fusion (PBF-LB/M) process, the microstructure and therefore the mechanical performance of test coupons are not representative of parts of the same material in every case. This work summarizes part of the results of an ongoing cooperation between BAM and BASF, which aims at addressing this issue by designing dedicated specimens, representative of the fatigue properties of the real component. The considered case study consisted in the fabrication and characterization of the fatigue properties of a pressure vessel made of AISI 316L. The first phase of the project was devoted to the process monitoring to understand the relationship between process parameters and temperature distribution during the fabrication of the component. Finite element models were tuned on the experimental data from the process monitoring and simulations of the temperature field in the component were conducted. The numerical results were in good agreement with the temperature profiles measured during the fabrication of the component. The second phase dealt with the evaluation of the fatigue and fatigue crack propagation properties on specimens extracted from different regions of the pressure vessel. The experimental investigations showed significant differences in hoop and longitudinal direction. A clear dependence of the fatigue properties on heat accumulation (temperature distribution) and defect size was pointed out. The third phase encompassed the fabrication and testing of the representative specimens. Numerical simulations were used to design specimens displaying the same temperature profile as in the most critical region of the component. The fatigue testing of the representative specimens is subject of ongoing work.
T2 - 8. DVM-Tagung Additiv gefertigte Bauteile und Strukturen
CY - Berlin, Germany
DA - 28.11.2023
KW - PBF-LB/M
KW - Process Monitoring
KW - Process Simulation
KW - Fatigue
KW - Representative Specimens
PY - 2023
AN - OPUS4-58973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Albornoz, Ricardo Valencia
A1 - Antypov, Dmytro
A1 - Blanke, Gerd
A1 - Borges, Itamar
A1 - Marulanda Bran, Andres
A1 - Cheung, Joshua
A1 - Collins, Christopher M.
A1 - David, Nicholas
A1 - Day, Graeme M.
A1 - Deringer, Volker L.
A1 - Draxl, Claudia
A1 - Eardley-Brunt, Annabel
A1 - Evans, Matthew L.
A1 - Fairlamb, Ian
A1 - Fieseler, Kate
A1 - Franklin, Barnabas A.
A1 - George, Janine
A1 - Grundy, Joanna
A1 - Johal, Jay
A1 - Kalikadien, Adarsh V.
A1 - Kapil, Venkat
A1 - Kotopanov, Lyubomir
A1 - Kumar, Vishank
A1 - Kuttner, Christian
A1 - Lederbauer, Magdalena
A1 - Ojeda-Porras, Andrea Carolina
A1 - Pang, Jiayun
A1 - Parkes, Michael
A1 - Pemberton, Miles
A1 - Ruscic, Branko
A1 - Ryder, Matthew R.
A1 - Sakaushi, Ken
A1 - Saleh, Gabriele
A1 - Savoie, Brett M.
A1 - Schwaller, Philippe
A1 - Skjelstad, Bastian Bjerkem
A1 - Sun, Wenhao
A1 - Taniguchi, Takuya
A1 - Taylor, Christopher R.
A1 - Torrisi, Steven
A1 - Vishnoi, Shubham
A1 - Walsh, Aron
A1 - Wu, Ruiqi
T1 - Discovering trends in big data: General discussion
N2 - This article is a discussion of the paper "Specialising and analysing instruction-tuned and byte-level language models for organic reaction prediction" by Jiayun Pang and Ivan Vulić (Faraday discussions, 2025, 256, 413-433).
KW - Automation
KW - Big data
KW - Machine learning
KW - Materials design
KW - Chemically complex materials
PY - 2025
DO - https://doi.org/10.1039/D4FD90063D
SN - 1359-6640
SN - 1364-5498
VL - 256
IS - Themed collection: Data-driven discovery in the chemical sciences
SP - 520
EP - 550
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-62652
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Formation of Creep Damage of 316L Produced by Laser Powder Bed Fusion
N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed.
T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024
CY - Berlin, Germany
DA - 12.06.2024
KW - AISI 316L
KW - Additive Manufacturing
KW - Computed Tomography
KW - Creep
KW - Laser Powder Bed Fusion
KW - Microstructure
KW - PBF-LB/M/316L
PY - 2024
AN - OPUS4-60295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ávila Calderón, Luis
A1 - Shakeel, Y.
A1 - Schriever, Sina
A1 - Gedsun, A.
A1 - Forti, M.
A1 - Jordan, Hans
A1 - Han, Ying
A1 - Baer, O.
A1 - Aversa, R.
A1 - Olbricht, Jürgen
A1 - Hammerschmidt, T.
A1 - Hickel, T.
A1 - Skrotzki, Birgit
T1 - NFDI-MatWerk/IUC02 Data schema for creep data of Ni-based superalloys including a comprehensive documentation of test results and metadata
N2 - This data schema was developed within the infrastructure use case IUC02: “Framework for curation and distribution of reference datasets” of the consortium NFDI-MatWerk. It intends to define a structured approach for collecting all required information on a creep experiment using the established terminology of the respective test standard ISO 204:2022 and additional terminology agreed upon by the domain experts. The individual entries are grouped according to their content type and sub-summarized under respective headlines, thereby suggesting a basic categorization and a related hierarchy of concepts. This hierarchy can be similarly applied to other test methods and different metallic (and other) materials.
In version 1.1 some editorial and formal changes were made.
KW - NFDI-MatWerk
KW - Digitalisierung
KW - Referenzdaten
KW - Kriechen
KW - Ni-based Superalloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611629
DO - https://doi.org/10.5281/zenodo.11668375
PB - Zenodo
CY - Geneva
AN - OPUS4-61162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX - Forschungsdaten beim Metallschutzgasschweißen
N2 - Ziel des WelDX Forschungsvorhabens ist es, den Austausch wissenschaftlicher Forschungsdaten aus dem Bereich der Schweißtechnik auf Basis eines einheitlichen Open Source Dateiformates zu ermöglichen und damit die Einhaltung und Dokumentation geeigneter Qualitätsstandards zu fördern. Im Zuge der Projektarbeit wird die Zusammenarbeit und der Wissenstransfer schweißtechnischer Institute zunächst auf nationaler Ebene gefördert und die Bildung eines von der Fachcommunity getragenen Kuratoriums zur Betreuung und Weiterentwicklung des Dateiformates und der Ausarbeitung zugehöriger Qualitätsstandards angestrebt.
Der Vortrag gibt eine Übersicht zur Motivation, der technischen Umsetzung des Dateiformates sowie möglicher Anwendungsfälle.
T2 - WelDX Open Science Seminar
CY - Berlin, Germany
DA - 04.03.2020
KW - Schweißen
KW - Forschungsdatenmanagement
KW - Open science
KW - Open data
KW - Digitalisierung
PY - 2020
AN - OPUS4-50678
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blasón Gonzalez, Sergio
T1 - Determination of the fatigue limit and initial crack length by means of fracture mechanics
N2 - The fatigue design of metallic components is usually based on two different approaches, namely total life and damage tolerance. The former takes into account both the initiation and propagation stages. The latter is based on fracture mechanics and needs an initial defect, which propagates until the critical size under cyclic loading, provided it is large enough. In this case, a residual life rather than a total life is obtained. The overall lifetime of a cyclically loaded structure involves four consecutive stages: a) crack initiation; b) propagation of microstructurally short cracks; c) propagation of physically/mechanically short cracks; d) propagation of long cracks. Considering the propagation from the short crack regime, the damage tolerance approach can be extended to adequately calculate the total life of a component.
The fatigue strength of metallic materials containing defects depends on the non-propagation condition of small cracks emanating from these defects. In this work, the presence of mechanically short cracks from the beginning of the component's life is considered. Consequently, the methodology of analysis must be able to treat adequately local ligament yielding effects typical for short cracks and must include the thorough description of the crack closure effect up to the long-crack regime. In the analysis based on long cracks, the linear-elastic condition is mostly satisfied which allows the use of the linear elastic parameter ΔK for describing the crack driving force. On the contrary, this assumption is not adequate for mechanically short cracks because the crack depth is in the order of the plastic zone. Instead, an elastic-plastic driving force should be considered. Furthermore, the gradual build-up of the plasticity-induced crack closure effect must be considered, which implies a transition from the intrinsic (effective) threshold value, ΔKth,eff, to the long-crack threshold, ΔKth,LC.
The effective component is a material parameter which is dependent on the elastic properties and crystal lattice. The gradual build-up of crack-closure is described by ΔKth,op which is a function of the plastic properties, grain-size, environment conditions, load ratio and crack-depth. The crack closure can be characterized experimentally by the so-called cyclic R-curve. Some other crack closure effects, such as roughness or oxide-debris induced, might be incorporated as well.
The knowledge of the cyclic R-curve can be useful to determine the largest non-propagating crack size at the material fatigue limit. This is realised by means of the so-called cyclic R-curve analysis: The tangent criterion between the driving force and the cyclic R-curve define the transition between crack arrest and propagation. In this regard, a0 is defined as that crack depth which will only grow into a non-propagating crack due to the development of crack closure.
The procedure outlined briefly here has been successfully applied to the determination of the fatigue limits of steel weldments. Considering the stochastic distribution of the weld geometric parameters (namely, weld toe radius, the flank angle, and the excess weld metal) it is possible to perform a full probabilistic cyclic R-curve analysis and determine this way the statistical distribution of the initial crack size at the weld toe at the fatigue limit.
T2 - Virtual Conference on Mechanical Fatigue
CY - Online meeting
DA - 09.09.2020
KW - Cyclic R-curve
KW - Fracture Mechanics
KW - Fatigue Strength
KW - Short Crack Propagation
PY - 2020
AN - OPUS4-51238
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
A1 - Hammerschmidt, T.
A1 - Gedsun, A.
A1 - Forti, M.
A1 - Olbricht, Jürgen
A1 - Stotzka, R.
A1 - Skrotzki, Birgit
T1 - IUC02 Framework for Curation and Distribution of Reference Datasets using Creep Data of Ni-Base Superalloys as an Example
N2 - In our current view, reference datasets in the MSE domain represent specific material properties, e.g., structural, mechanical, … characteristics. A reference dataset must fulfill high-quality standards, not only in precision of measurement but also in a comprehensive documentation of material, processing, and testing history (metadata). This Infrastructure Use Case (IUC) aims to develop a framework for generating reference material datasets using creep data of a single crystal Ni-based superalloy as a best practice example. In a community-driven process, we aim to encourage the discussion and establish a framework for the creation and distribution of reference material datasets. In this poster presentation, we highlight our current vision and activities and intend to stimulate the discussion about the topic reference datasets and future collaborations and work.
T2 - NFDI-MatWerk Conference
CY - Siegburg, Germany
DA - 27.06.2023
KW - Referenzdaten
KW - Reference data
KW - Syngle Crystal alloy
KW - Creep
KW - Metadata schema
PY - 2023
AN - OPUS4-57923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Narsabadi, Hossein
A1 - Vafaeenezhad, H.
A1 - Klotz, U.E.
A1 - Tiberto, D.
A1 - Hosseinabadi, F.
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
A1 - Skrotzki, Birgit
T1 - XCT-assisted micromechanical modeling of the effect of pores on the plastic deformation and mechanical characteristics of PBF-LB/M-produced copper alloys
N2 - Due to the low absorption of fiber laser by copper particles, the laser-based powder bed fusion (PBF-LB/M) processing of copper components is accompanied by the development of different types of porosities within the printed samples. This research aims to assess the consequences of various process-induced pores on the me
chanical characteristics and deformation of PBF-LB/M-produced copper alloys. Several copper alloys were processed using metal-coated particles and varied laser intensities, yielding samples with different types and amounts of porosities. For instance, CuCrZr alloys processed at 325 J/mm³ and 257 J/mm³ had 0.009 % and 1.117 % porosities, dominated by keyhole and lack-of-fusion pores, respectively. Moreover, PBF-LB/M pro cessing of Cr- and Nb-coated CuNi3SiCr particles accompanied by the generation of 0.004 % and 1.861 % porosities within the samples, predominantly featuring metallurgical and oxidation pores, respectively.
Compression and nanoindentation tests revealed that the CuNi3SiCr alloy exhibited superior mechanical properties compared to the CuCrZr sample (nanoindentation hardness values 2.2 GPa and 1.4 GPa, respectively), while the presence of lack-of-fusion pores notably diminished their mechanical performance. X-ray computed tomography (XCT) reconstruction slices and scanning electron microscopy (SEM) images were then used for developing the representative volume elements (RVEs) based micromechanical models. The micromechanical
simulations established a structure-property correlation that can simulate the compressive deformation and mechanical characteristics of PBF-LB/M-produced copper alloys as a function of their incorporated pore characteristics. Due to the closure of the pores at the first stages of deformation, samples with minimal keyhole and metallurgical porosities exhibited homogeneous plastic deformation. On the other side, based on the JohnsonCook model, strain concentration and crack propagation around the lack-of-fusion pores lead to damage initi
ation in the printed samples at a strain level of 5 %
KW - X-ray Computed tomography
KW - Defects
KW - Copper alloys
KW - PBF-LB/M
KW - Micromechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624004
DO - https://doi.org/10.1016/j.msea.2025.147836
SN - 0921-5093
VL - 924
PB - Elsevier B.V.
AN - OPUS4-62400
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, André
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - Influence of welding parameters on electromagnetic supported degassing of die-casted and wrought aluminum
N2 - Laser beam welding of aluminum die casting is challenging. A large quantity of gases (in particular, hydrogen) is absorbed by aluminum during the die-cast manufacturing process and is contained in the base material in solved or bound form. After remelting by the laser, the gases are released and are present in the melt as pores. Many of these metallurgic pores remain in the weld seam as a result of the high solidification velocities. The natural (Archimedean) buoyancy is not sufficient to remove the pores from the weld pool, leading to process instabilities
and poor mechanical properties of the weld. Therefore, an electromagnetic (EM) system is used to apply an additional buoyancy
component to the pores. The physical mechanism is based on the generation of Lorentz forces, whereby an electromagnetic pressure is introduced into the weld pool. The EM system exploits the difference in electrical conductivity between poorly conducting pores (inclusions) and the comparatively better conducting aluminum melt to increase the resulting buoyancy velocity of the pores. Within the present study, the electromagnetic supported degassing is investigated in dependence on the laser beam power, welding velocity, and electromagnetic flux density. By means of a design of experiments, a systematic variation of these parameters is carried out for partial penetration laser beam welding of 6mm thick sheets of wrought aluminum alloy AlMg3 and die-cast aluminum alloy AlSi12(Fe), where the wrought alloy serves as a reference. The proportion of pores in the weld seams is determined using x-ray images, computed tomography images, and cross-sectional images. The results prove a significant reduction of the porosity up to 70% for both materials as a function of the magnetic flux density.
T2 - ICALEO 2019
CY - Orlando, FL, USA
DA - 07.10.2019
KW - Laser beam welding
KW - Electromagnetic supported degassing
KW - Die-casted aluminum
PY - 2020
DO - https://doi.org/10.2351/7.0000064
VL - 32
IS - 2
SP - 022031-1
EP - 022031-8
PB - AIP Publishing
AN - OPUS4-50728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
A1 - Shakeel, Yusra
T1 - NFDI-MatWerk PP18 / IUC02 Reference Data: Creep Data of a single crystalline Ni-Base Alloy
N2 - Reference datasets in the MSE domain represent specific material properties, e.g., structural, mechanical, … characteristics. A reference dataset must fulfill high-quality standards, not only in precision of measurement but also in a comprehensive documentation of material, processing, and testing history (metadata). This Infrastructure Use Case (IUC) of the consortium Materials Science and Engineering (MatWerk) of National Research Data Infrastructure (NFDI) aims to develop, together with BAM and other Participant Projects (PP), a framework for generating reference material datasets using creep data of a single crystal Ni-based superalloy as a best practice example. In a community-driven process, we aim to encourage the discussion and establish a framework for identifying reference material datasets. In this poster presentation, we highlight our current vision and activities and intend to stimulate the discussion about the topic reference datasets and future collaborations and work.
T2 - All-Hands-on-Deck congress from the NFDI-MatWerk
CY - Siegburg, Germany
DA - 08.03.2023
KW - Referenzdaten
KW - Reference data
KW - Creep
KW - Syngle Crystal alloy
KW - Metadata schema
PY - 2023
AN - OPUS4-57146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rehmer, Birgit
A1 - Bayram, Faruk
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
T1 - BAM reference data: Temperature-dependent Young's and shear modulus data for additively and conventionally manufactured variants of Ni-based alloy Inconel IN718
N2 - The elastic properties (Young's modulus, shear modulus) of Ni-based alloy Inconel IN718 were investigated between room temperature and 800 °C in an additively manufactured variant (laser powder bed fusion, PBF‑LB/M) and from a conventional process route (hot rolled bar). The moduli were determined using the dynamic resonance method. The data set includes information on processing parameters, heat treatments, grain size, specimen dimensions and weight, Young’s and shear modulus as well as their measurement uncertainty.
The dataset was generated in an accredited testing lab using calibrated measuring equipment. The calibrations meet the requirements of the test procedure and are metrologically traceable. The dataset was audited as BAM reference data.
KW - Elastic modulus
KW - Young's modulus
KW - Shear modulus
KW - Additive manufacturing
KW - IN718
PY - 2023
DO - https://doi.org/10.5281/zenodo.7813824
PB - Zenodo
CY - Geneva
AN - OPUS4-57287
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rehmer, Birgit
A1 - Bayram, Faruk
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
T1 - BAM reference data: Temperature-dependent Young's and shear modulus data for additively and conventionally manufactured variants of austenitic stainless steel AISI 316L
N2 - The elastic properties (Young's modulus, shear modulus) of austenitic stainless steel AISI 316L were investigated between room temperature and 900 °C in an additively manufactured variant (laser powder bed fusion, PBF‑LB/M) and from a conventional process route (hot rolled sheet). The moduli were determined using the dynamic resonance method. The data set includes information on processing parameters, heat treatments, grain size, specimen dimensions and weight, Young’s and shear modulus as well as their measurement uncertainty.
The dataset was generated in an accredited testing lab using calibrated measuring equipment. The calibrations meet the requirements of the test procedure and are metrologically traceable. The dataset was audited as BAM reference data.
KW - Elastic modulus
KW - Young's modulus
KW - Shear modulus
KW - Additive manufacturing
KW - AISI 316L
PY - 2023
DO - https://doi.org/10.5281/zenodo.7813835
PB - Zenodo
CY - Geneva
AN - OPUS4-57288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rosen, Andrew S.
A1 - Gallant, Max
A1 - George, Janine
A1 - Riebesell, Janosh
A1 - Sahasrabuddhe, Hrushikesh
A1 - Shen, Jimmy-Xuan
A1 - Wen, Mingjian
A1 - Evans, Matthew L.
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Rignanese, Gian-Marco
A1 - Persson, Kristin A.
A1 - Jain, Anubhav
A1 - Ganose, Alex M.
T1 - Jobflow: Computational Workflows Made Simple
N2 - Jobflow is a free, open-source library for writing and executing workflows. Complex workflows can be defined using simple python functions and executed locally or on arbitrary computing resources using the FireWorks workflow manager.
Some features that distinguish jobflow are dynamic workflows, easy compositing and connecting of workflows, and the ability to store workflow outputs across multiple databases.
KW - Automation
KW - Workflows
KW - Computational Materials Science
PY - 2024
DO - https://doi.org/10.5281/zenodo.10466868
PB - Zenodo
CY - Geneva
AN - OPUS4-59313
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Bruno, Giovanni
A1 - Hilgenberg, Kai
T1 - Towards a Methodology for Component Design of Metallic AM Parts Subjected to Cyclic Loading
N2 - The safe fatigue design of metallic components fabricated by additive manufacturing (AM) is still a largely unsolved problem. This is primarily due to (a) a significant inhomogeneity of the material properties across the component; (b) defects such as porosity and lack of fusion as well as pronounced surface roughness of the asuilt components; and (c) residual stresses, which are very often present in the as‐built parts and need to be removed by post‐fabrication treatments. Such morphological and microstructural features are very different than in conventionally manufactured parts and play a much bigger role in determining the fatigue life. The above problems require specific solutions with respect to the identification of the critical (failure) sites in AM fabricated components. Moreover, the generation of representative test specimens characterized by similar temperature cycles needs to be guaranteed if one wants to reproducibly identify the critical sites and establish fatigue assessment methods taking into account the effect of defects on crack initiation and early propagation. The latter requires fracture mechanics‐based approaches which, unlike common methodologies, cover the specific characteristics of so‐called short fatigue cracks. This paper provides a discussion of all these aspects with special focus on components manufactured by laser powder bed fusion (L‐PBF). It shows how to adapt existing solutions, identifies fields where there are still gaps, and discusses proposals for potential improvement of the damage tolerance design of L‐PBF components
KW - L‐PBF
KW - Fatigue
KW - Fracture
KW - Defects
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525822
DO - https://doi.org/10.3390/met11050709
VL - 11
IS - 5
SP - 709
PB - MDPI
CY - Basel
AN - OPUS4-52582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis
A1 - Rehmer, Birgit
A1 - Schriever, Sina
A1 - Ulbricht, Alexander
A1 - Agudo Jácome, Leonardo
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
A1 - Evans, Alexander
T1 - Creep and creep damage behavior of stainless steel 316L manufactured by laser powder bed fusion
N2 - This study presents a thorough characterization of the creep properties of austenitic stainless steel 316L produced by laser powder bed fusion (LPBF 316L) contributing to the sparse available data to date. Experimental results (mechanical tests, microscopy, X-ray computed tomography) concerning the creep deformation and damage mechanisms are presented and discussed. The tested LPBF material exhibits a low defect population, which allows for the isolation and improved understanding of the effect of other typical aspects of an LPBF microstructure on the creep behavior. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant of 316L was also tested. To characterize the creep properties, hot tensile tests and constant force creep tests at 600 °C and 650 °C are performed. The creep stress exponents of the LPBF material are smaller than that of the conventional variant. The primary and secondary creep stages and the times to rupture of the LPBF material are shorter than the hot rolled 316L. Overall the creep damage is more extensive in the LPBF material. The creep damage of the LPBF material is overall mainly intergranular. It is presumably caused and accelerated by both the appearance of precipitates at the grain boundaries and the unfavorable orientation of the grain boundaries. Neither the melt pool boundaries nor entrapped gas pores show a significant influence on the creep damage mechanism.
KW - 316L
KW - Laser Powder Bed Fusion (LPBF)
KW - Creep behavior
KW - Additive Manufacturing
KW - AGIL
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539373
DO - https://doi.org/10.1016/j.msea.2021.142223
SN - 0921-5093
VL - 830
SP - 142223
PB - Elsevier B.V.
AN - OPUS4-53937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Abdou-Rahaman Fadul, Naïssa
A1 - Frasca, Daniele
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
T1 - Multifunctional graphene nanofiller in flame retarded polybutadiene/chloroprene/carbon black composites
N2 - To curtail flammability risks and improve material properties, flame retardants (FRs) and fillers are mixed into rubbers. High loadings of aluminum trihydroxide (ATH) and carbon black (CB) are the most used FRs and reinforcing additive, respectively, in rubbers. To reduce loading without losing mechanical properties, partial substitution of ATH as well as CB by low amounts of multilayer graphene (MLG) nanoparticles is investigated. The high aspect ratio MLG is made of ten graphene sheets. In polybutadiene/chloroprene (BR/CR) nanocomposites 3 phr MLG replaced 15 phr CB and/or 3 phr ATH. Material and mechanical properties as well as fire behavior of the nanocomposites are compared to BR/CR with 20 phr CB both with and without 50 phr ATH. MLG appears as a promising nanofiller to improve the functional properties: replacement of CB improved rheological, curing, and mechanical properties; substitution of ATH improved nanocomposite properties without affecting flame retardancy.
KW - Nanocomposites
KW - Rubber
KW - Multilayer graphene
KW - Carbon black
KW - Polybutadiene/chloroprene
KW - Graphene
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523468
DO - https://doi.org/10.1515/epoly-2021-0026
SN - 1618-7229
VL - 21
IS - 1
SP - 244
EP - 262
PB - De Gruyter
AN - OPUS4-52346
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
T1 - The effect of the environmental conditions on the threshold against fatigue crack propagation
N2 - The threshold against fatigue crack propagation (ΔKth) is a crucial parameter for the damage tolerance assessment of engineering components subjected to cyclic loading and it is composed by two distinct components, one intrinsic, dependent on the elastic material properties and the lattice type, and one extrinsic, related to the occurrence of crack closure effects. An important issue is that several factors can influence ΔKth and, in general, the fatigue crack propagation behavior. In this work, the influence of the experimental procedure, air humidity, stress ratio and test frequency on da/dN-ΔK data has been investigated. Results are discussed with their potential causes and consequences on the calculations of the residual lifetime.
KW - Fatigue crack propagation threshold
KW - Crack closure effect
KW - Experimental procedure
KW - Environmental conditions
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544905
DO - https://doi.org/10.1016/j.prostr.2022.03.030
VL - 38
SP - 292
EP - 299
PB - Elsevier B.V.
AN - OPUS4-54490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Müller, Patrick
A1 - Bertin, Annabelle
A1 - Schartel, Bernhard
T1 - Hyperbranched Rigid Aromatic Phosphorus-Containing Flame Retardants for Epoxy Resins
N2 - A rigid aromatic phosphorus-containing hyperbranched flame retardant structure is synthesized from 10-(2,5 dihydroxyphenyl)-10H-9-oxa-
10-phosphaphenanthrene-10-oxide (DOPO-HQ), tris(4-hydroxyphenyl)phosphine oxide (THPPO), and 1,4-terephthaloyl chloride (TPC). The resulting poly-(DOPO-HQ/THPPO-terephthalate) (PDTT) is implemented as a flame retardant into an epoxy resin (EP) at a 10 wt% loading. The effects on EP are compared with those of the monomer DOPO-HQ and triphenylphosphine oxide (OPPh3) as low molar mass flame retardants. The glass transition temperature, thermal decomposition, flammability (reaction to small flame), and burning behavior of the thermosets are investigated using differential scanning calorimetry, thermogravimetric analysis, pyrolysis combustion flow calorimetry, UL 94-burning chamber testing, and cone calorimeter measurements.
Although P-contents are low at only 0.6 wt%, the study aims not at attaining V-0, but at presenting a proof of principle: Epoxy resinswith PDTT show promising fire performance, exhibiting a 25% reduction in total heat evolved (THE), a 30% reduction in peak heat release rate (PHRR) due to flame inhibition (21% reduction in effective heat of combustion (EHC)), and an increase in Tg at the same time. This study indicates that rigid aromatic hyperbranched polymeric structures offer a promising route toward multifunctional flame retardancy.
KW - Hyperbranched
KW - Aromatic
KW - Phosphorus
KW - Phosphine oxide
KW - DOPO
KW - Flame retardant
KW - Xpoxy resin
KW - Rigid
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525910
DO - https://doi.org/10.1002/mame.202000731
SN - 1439-2054
VL - 306
IS - 4
SP - 731
PB - Wiley
AN - OPUS4-52591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhu, Jiangchao
A1 - Madia, Mauro
A1 - Schurig, Michael
A1 - Kruse, Julius
A1 - Conrad, Fabian
A1 - Schlums, Hartmut
A1 - Kontermann, Christian
A1 - Zerbst, Uwe
T1 - On the use of representative specimens for the structural integrity assessment of safety-relevant rotating components
N2 - Safety-relevant components, for which a failure in service could have catastrophic consequences, are usually designed for extremely low probability of failure and they are subjected to stringent part qualification procedures according to guidelines set by regulatory agencies. Manufacturers are often forced to perform tests on full scale or scaled components to ensure the structural integrity under defined loading conditions, which usually implies a huge experimental and financial effort. Therefore, companies try to develop new strategies such as digital twins, which allow to massively reduce costs, without compromising safety. This work presents a new quasi-static testing and assessment concept, the main idea of which is to replace, or at least reduce, the experimental testing on components by testing specimens representative of the component.
Fracture mechanics specimens have been designed iteratively by numerical simulations to match the stress state at the crack-tip of the maximum permissible defect defined by regulatory agencies for the component. Potentially, the major benefit of the proposed approach is that the tests can be performed on conventional laboratory testing machines. The effectiveness of the methodology is demonstrated in case of the structural integrity assessment of a Ni-base superalloy aero-engine turbine disk at overspeed conditions.
KW - Structural integrity
KW - Turbine disk
KW - Burst
KW - Fracture mechanics
KW - Representative specimens
KW - Quasi-static testing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624208
DO - https://doi.org/10.1016/j.engfracmech.2024.110710
SN - 0013-7944
VL - 314
SP - 1
EP - 23
PB - Elsevier Ltd.
AN - OPUS4-62420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX – progress report on the welding data exchange format
N2 - The presentation shows the current development status of the Welding Data Exchange (weldx) format based on the Advanced Scientific Data Format (ASDF).
The use of a complete single pass arc welding experiment example stored in a single weldx file and validated against a predefined schema definition is presented.
The example includes generic experimental metadata, the workpiece geometry and materials definition following associated standards, the weld process spatial movement description, the welding process parameter descriptions and welding process measurements. The inclusion of 3D scan data of the workpiece description is also included.
The full code and data is available on GitHub: https://github.com/BAMWelDX/IIW2021_joint_intermediate_CXII
T2 - IIW joint intermediate meeting Comm. I,IV,XII,SG212 2021
CY - Online meeting
DA - 30.03.2021
KW - WelDX
KW - Research data management
KW - Open science
KW - Arc welding
KW - Digitalization
PY - 2021
AN - OPUS4-52661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strauß, Lea
A1 - Duarte, Larissa
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Löwisch, Günther
T1 - An equivalent stress approach for predicting fatigue behavior of additively manufactured AlSi10Mg
N2 - Laser-based powder bed fusion (PBF-LB) is an advanced additive manufacturing technique renowned for its precision and capability to fabricate complex metal components. However, the high thermal gradients and rapid cooling rates intrinsic to this process introduce significant process-induced effects, such as inhomogeneities, surface roughness, anisotropy, and residual stress, all of which critically influence the fatigue behavior of the produced parts. This study investigates the fatigue performance of AlSi10Mg samples produced by PBF-LB, examining the impact of varying surface conditions, geometries, and residual stress levels. Fatigue-life prediction models are formulated based on nominal stress amplitude, residual stress, form factor, crack-initiating inhomogeneity, and surface roughness, with smooth samples serving as a baseline reference. The study presents two empirical models for predicting fatigue life and fatigue strength using S–N curves and the Kitagawa–Takahashi diagram with the El Haddad approach, derived from comprehensive experimental data, including finite element modeling, fatigue-life measurements, surface roughness evaluations, and residual stress analysis.
KW - AlSi10Mg
KW - Kitagawa–Takahashi diagram
KW - El Haddad
KW - Equivalent stress
KW - Fatigue-life prediction
KW - PBF-LB/M
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625176
DO - https://doi.org/10.1007/s40964-025-00974-0
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-62517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Norouzi, Ebrahim
A1 - Sack, Harald
A1 - Skrotzki, Birgit
T1 - Performance Evaluation of Upper‐Level Ontologies in Developing Materials Science Ontologies and Knowledge Graphs
N2 - This study tackles a significant challenge in ontology development for materials science: selecting the most appropriate upper‐level ontologies for creating application‐level ontologies and knowledge graphs. Focusing on the use case of Brinell hardness testing, the research assesses the performance of various top‐level ontologies (TLOs)—basic formal ontology (BFO), elementary multiperspective material ontology (EMMO), and provenance ontology (PROVO)—in developing Brinell testing ontologies (BTOs). Consequently, three versions of BTOs are created using combinations of these TLOs along with their integrated mid‐ and domain‐level ontologies. The performance of these ontologies is evaluated based on ten parameters: semantic richness, domain coverage, extensibility, complexity, mapping efficiency, query efficiency, integration with other ontologies, adaptability to different data contexts, community acceptance, and documentation and maintainability. The results show that all candidate TLOs can effectively develop BTOs, each with its distinct advantages. BFO provides a well‐structured, understandable hierarchy, and excellent query efficiency, making it suitable for integration across various ontologies and applications. PROVO demonstrates balanced performance with strong integration capabilities. Meanwhile, EMMO offers high semantic richness and domain coverage, though its complex structure impacts query efficiency and integration with other ontologies.
KW - Materials Science
KW - Ontology
KW - Knowledge Graph
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612227
DO - https://doi.org/10.1002/adem.202401534
SN - 1527-2648
SP - 1
EP - 18
PB - Wiley
AN - OPUS4-61222
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Yusenko, Kirill
A1 - King, Andrew
A1 - Meyer, Klas
A1 - Al-Sabbagh, Dominik
A1 - Villajos, José Antonio
A1 - Emmerling, Franziska
T1 - Lighting up industrial mechanochemistry: Real-time in situ monitoring of reactive extrusion using energy-dispersive X-ray diffraction
N2 - Mechanochemistry is an environmentally friendly synthetic approach that enables the sustainable production of a wide range of chemicals while reducing or eliminating the need for solvents. Reactive extrusion aims to move mechanochemistry from its conventional gram-scale batch reactions, typically performed in laboratory ball mills, to a continuous, large-scale process. Meeting this challenge requires in situ monitoring techniques to gain insights into reactive extrusion and its underlying processes. While the effectiveness of in situ Raman spectroscopy in providing molecular-level information has been demonstrated, our study uses energy-dispersive X-ray diffraction to monitor reactive extrusion in real time at the crystalline level. Our results provide previously unavailable control over the reactive extrusion process, promoting its perception as an industrially feasible green alternative to traditional solvent-based syntheses.
KW - Mechanochemistry
KW - Reactive extrusion
KW - Green chemistry
KW - In situ studies
KW - Time-resolved in situ
KW - TRIS
KW - Synchrotron radiation
KW - Scalable synthesis
KW - Solid-state reactions
KW - Reaction mechanisms
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613969
DO - https://doi.org/10.1016/j.chempr.2024.07.033
VL - 10
IS - 11
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-61396
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Fedelich, Bernard
A1 - Jokisch, T.
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Fatigue crack growth behavior of Alloy 247DS brazed joints at high temperatures
N2 - Gas turbine components made of nickel-based alloys can be repaired through diffusion brazing. However, process-induced imperfections, defects within the brazing zone, and material property mismatches between the braze alloy and base material may facilitate crack initiation and propagation, ultimately leading to early component failure. To gain insight into the crack growth mechanism and quantitatively characterize fatigue crack growth behavior within brazing zones, fatigue crack growth (FCG) experiments were conducted on brazed joint specimens of nickel-based alloy Alloy 247DS at a temperature of 950 ◦C and a stress ratio R = 0.1. The FCG tests were complemented by fractographic and microstructural analyses, to elucidate the relationship between crack growth mechanisms and the microstructure of the brazed joint. The results demonstrate stable crack propagation within the brazing zone and the nickel-based braze alloy. The latter contains brittle eutectic boride phases and intermetallic phases that reduce the resistance to crack propagation compared to the parent material. This study demonstrates the applicability of standard FCG experimental procedures to fusion zones, thereby enabling a preliminary understanding of crack growth behavior in brazing zones.
KW - Diffusion brazing
KW - High-temperature fatigue crack growth
KW - Nickel-based alloys
KW - Alloy 247DS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615250
DO - https://doi.org/10.1016/j.msea.2024.147488
SN - 0921-5093
VL - 918
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-61525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanna, Naveen
T1 - Ermittlung von Kitagawa-Takahashi-Diagrammen mittels Gleichstrom-Potentialsondenmessungen
N2 - Das Kitagawa-Takahashi Diagramm ist ein wichtiges Werkzeug zur Beschreibung der ausgeprägten Langzeitfestigkeit fehlerbehafteter Bauteile. Insbesondere im technisch relevanten Übergangsbereich unterscheiden sich jedoch die verwendeten Modelle. Daher ist für eine sichere Aussage eine experimentelle Absicherung in diesem Bereich zwingend notwendig. In dieser Arbeit wird eine Methode vorgestellt, die eine einfache und schnelle Absicherung des Verlaufs im Übergangsbereich erlaubt. Hierzu werden in Flachproben mittels eines Gravierlasers scharfe Kerben mit einer definierten Breite und Tiefe eingebracht. Die so präparierten Proben werden mit blockweise steigender Last bis zum Bruch ermüdet. Die Erkennung von Anrissen erfolgt mittels einer Gleichstrom-Potentialsonde mit der auch die Länge des Lastblocks gesteuert wird.
T2 - Tagung AK-Bruch 2025
CY - Cologne, Germany
DA - 18.02.2025
KW - Ausgeprägte Langzeitfestigkeit
KW - Materialdefekte
KW - KT-Diagramm
KW - Gleichstrom-Potentialsonde
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625992
AN - OPUS4-62599
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hickel, Tilmann
A1 - Richter, Silke
A1 - Bitzek, E.
A1 - Ávila Calderón, Luis
A1 - Gedsun, A.
A1 - Forti, M.
A1 - Hammerschmidt, T.
A1 - Olbricht, Jürgen
A1 - Skrotzki, Birgit
T1 - NFDI-MatWerk/IUC02 Definition for Reference Data of Materials
N2 - This definition was agreed within the infrastructure use case IUC02 “Framework for curation and distribution of reference datasets” of the consortium NFDI-MatWerk. It is broadly formulated to cover experimental and simulation MSE data and will be developed further in agreement with the MSE community.
KW - Referenzdaten
KW - Digitalisierung
KW - NFDI-MatWerk
KW - Research Data Management
KW - Reference Data
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611688
DO - https://doi.org/10.5281/zenodo.11667673
PB - Zenodo
CY - Geneva
AN - OPUS4-61168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scacco, F.
A1 - Zerbst, Uwe
A1 - Meneghetti, G.
A1 - Madia, Mauro
T1 - Comparison between PSM and IBESS approaches for the fatigue life estimation of weldments
N2 - In the framework of the fatigue assessment of welded components, several methods are available in design standards such as the nominal stress, hot-spot stress, notch stress and linear elastic fracture mechanics approaches. The present paper aims at comparing two advanced local approaches for the fatigue strength assessment of different welded joints made of steel. The first one is IBESS which is based on short crack fracture mechanics. The second one is the PSM which instead involves the strain energy density approach. Both methods will be briefly presented, and the fatigue life prediction results discussed. The results obtained for the joint geometries considered in this work show advantages and drawbacks of the approaches, which are thoroughly analysed as well.
KW - Fatigue
KW - Welded joints
KW - FAT class
KW - IBESS
KW - Peak stress method (PSM)
KW - Finite element (FE)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545139
DO - https://doi.org/10.1007/s40194-022-01284-7
SP - 1
EP - 23
PB - Springer
AN - OPUS4-54513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Mishurova, Tatiana
A1 - Madia, Mauro
A1 - Pirling, T.
A1 - Evans, Alexander
A1 - Klaus, M.
A1 - Haubrich, J.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Influence of a 265 °C heat treatment on the residual stress state of a PBF-LB/M AlSi10Mg alloy
N2 - Laser Powder Bed Fusion (PBF-LB/M) additive manufacturing (AM) induces
high magnitude residual stress (RS) in structures due to the extremely heterogeneous cooling and heating rates. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their generation and evolution after post-process heat treatments. In this study, one of the few of its kind, the RS relaxation induced in an as-built PBF-LB/M AlSi10Mg material by a low-temperature heat treatment (265 °C for 1 h) is studied by means of X-ray and neutron diffraction. Since the specimens are manufactured using a baseplate heated up to 200 °C, low RS are found in the as-built condition. After heat treatment a redistribution of the RS is observed, while their magnitude remains constant. It is proposed that the redistribution is induced by a repartition of stresses between the a-aluminium matrix and the silicon phase, as the morphology of the silicon phase is affected by the heat treatment. A considerable scatter is observed in the neutron diffraction RS profiles, which is principally correlated to the presence (or absence) of pockets of porosity developed at the borders of the chessboard pattern.
KW - Neutron diffraction
KW - Additive manufacturing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565115
DO - https://doi.org/10.1007/s10853-022-07997-w
SN - 1573-4803
VL - 57
SP - 22082
EP - 22098
PB - Springer Science + Business Media
CY - Dordrecht
AN - OPUS4-56511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna Christiane
A1 - Pauw, Brian Richard
A1 - Riechers, Birte
A1 - Zocca, Andrea
A1 - Rosalie, Julian
A1 - Maaß, Robert
A1 - Sturm, Heinz
A1 - Günster, Jens
T1 - Entering a new dimension in powder processing for advanced ceramics shaping
N2 - Filigree structures can be manufactured via two-photon-polymerization (2PP) operating in the regime of non-linear light absorption. For the first time it is possible to apply this technique to the powder processing of ceramic structures with a feature size in the range of the critical defect size responsible for brittle fracture and, thus, affecting fracture toughness of high-performance ceramics. In this way, tailoring of advanced properties can be achieved already in the shaping process. Traditionally, 2PP relies on transparent polymerizable resins, which is diametrically opposed to the usually completely opaque ceramic resins and slurries. Here we present a transparent and photocurable suspension of nanoparticles (resin) with very high mass fractions of yttria-stabilized zirconia particles (YSZ). Due to the extremely well dispersed nanoparticles, scattering of light can be effectively suppressed at the process-relevant wavelength of 800 nm. Sintered ceramic structures with a resolution of down to 500 nm were obtained. Even at reduced densities of 1 to 4 g/cm³, the resulting compressive strength with 4,5 GPa is equivalent or even exceeding bulk monolithic yttria stabilized zirconia. A ceramic metamaterial is born, where the mechanical properties of yttria stabilized zirconia are altered by changing geometrical parameters and gives access to a new class of ceramic materials.
KW - Two-photon-polymerization
KW - Ceramics
KW - Powder processing
KW - Transparency
KW - Meta material
KW - Yttria stabilized zirconia
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564598
DO - https://doi.org/10.1002/adma.202208653
SN - 1521-4095
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Werner, Tiago
A1 - Madia, Mauro
A1 - Zerbst, Uwe
T1 - Comparison of the fatigue behavior of wrought and additively manufactured AISI 316L
N2 - Additive manufacturing (AM) is becoming increasingly important in engineering applications due to the possibility of producing components with a high geometrical complexity allowing for optimized forms with respect to the in-service functionality. Despite the promising potential, AM components are still far from being used in safety-relevant applications, mainly due to a lack of understanding of the feedstock-process-properties-performance relationship. This work aims at providing a full characterization of the fatigue behavior of the additively manufactured AISI 316L austenitic stainless steel and a direct comparison with the fatigue performance of the wrought steel. To this purpose, a set of specimens has been produced by laser powder bed fusion (L-PBF) and subsequently heat treated at 900 °C for 1 hour for complete stress relief, whereas a second set of specimens has been machined out of hot-rolled plates. Low cycle fatigue (LCF) and high cycle fatigue (HCF) tests have been conducted for characterizing the fatigue behavior. The L-PBF material had a higher fatigue limit and better finite life performance compared to wrought material. Both, LCF and HCF-testing revealed an extensive cyclic softening.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Additive manufacturing
KW - L-PBF
KW - 316L
KW - Fatigue
KW - LCF
KW - HCF
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544952
DO - https://doi.org/10.1016/j.prostr.2022.03.056
SN - 2452-3216
VL - 38
SP - 554
EP - 563
PB - Elsevier B.V.
AN - OPUS4-54495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Yue
A1 - Schilling, Markus
A1 - von Hartrott, P.
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Ontopanel: A Tool for Domain Experts Facilitating Visual Ontology Development and Mapping for FAIR Data Sharing in Materials Testing
N2 - In recent years, the design and development of materials are strongly interconnected with the development of digital technologies. In this respect, efficient data management is the building block of material digitization and, in the field of materials science and engineering (MSE), effective solutions for data standardization and sharing of different digital resources are needed. Therefore, ontologies are applied that represent a map of MSE concepts and relationships between them. Among different ontology development approaches, graphical editing based on standard conceptual modeling languages is increasingly used due to its intuitiveness and simplicity. This approach is also adopted by the Materials-open-Laboratory project (Mat-o-Lab), which aims to develop domain ontologies and method graphs in accordance with testing standards in the field of MSE. To suit the actual demands of domain experts in the project, Ontopanel was created as a plugin for the popular open-source graphical editor diagrams.net to enable graphical ontology editing. It includes a set of pipeline tools to foster ontology development in diagrams.net, comprising imports and reusage of ontologies, converting diagrams to Web Ontology Language (OWL), verifying diagrams using OWL rules, and mapping data. It reduces learning costs by eliminating the need for domain experts to switch between various tools. Brinell hardness testing is chosen in this study as a use case to demonstrate the utilization of Ontopanel.
KW - Materials Testing
KW - Ontology
KW - Visual ontology development
KW - Data mapping
KW - FAIR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560339
DO - https://doi.org/10.1007/s40192-022-00279-y
SP - 1
EP - 12
PB - Springer
AN - OPUS4-56033
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Werner, Tiago
A1 - Blasón Gonzalez, Sergio
A1 - Madia, Mauro
A1 - Kruse, Julius
A1 - Benedetti, Matteo
T1 - Determination of fatigue crack propagation thresholds using small-scale specimens
N2 - The damage tolerance approach is widely used in the design and estimation of inspection intervals of safety-relevant metallic components subject to fatigue loading. The approach relies on the knowledge of the fatigue crack propagation characteristics, wherein a relevant role is played by the fatigue crack propagation threshold. Nevertheless, the use of material data determined by testing on conventional specimens is not straightforward in the case of thin-walled components such as turbine blades or additively manufactured parts, in which the local variation of material properties in highly stressed regions must be considered. In these cases, the possibility of investigating the fatigue crack propagation properties on a limited portion of material is crucial. For this purpose, a new test procedure has been developed for small-scale specimens which allows the determination of the intrinsic fatigue crack propagation threshold and the near-threshold regime. The validity and limitations of the method are demonstrated on the high strength steel S960QL, along with a comparison with data determined by testing on conventional geometries.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue crack propagation threshold
KW - Small-scale specimens
KW - High strength steel
KW - Crack-tip constraint
KW - Damage tolerance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544967
DO - https://doi.org/10.1016/j.prostr.2022.03.031
SN - 2452-3216
VL - 38
SP - 300
EP - 308
PB - Elsevier B.V.
AN - OPUS4-54496
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Kromm, Arne
A1 - Madia, Mauro
T1 - Investigation of residual stresses and microstructure effects on the fatigue behaviour of a L-PBF AlSi10Mg alloy
N2 - Al-Si alloys produced by Laser Powder Bed Fusion (L-PBF) techniques allow the fabrication of lightweight free-shape components that find space in aerospace, automotive, biomedical and military applications. Due to the high cooling rates occurring during the building process, L-PBF AlSi10Mg alloys exhibit an ultra-fine microstructure that leads to superior mechanical properties in the as-built condition compared to conventional cast Al-Si materials. Nevertheless, L-PBF processing induces high thermal gradients, leading to deleterious residual stress levels that must be considered to avoid part distortion and unpredicted failures. In order to relax detrimental residual stress and to increase the ductility, post-processing stress relief treatments are generally performed. In as-built condition the hypoeutectic AlSi10Mg microstructure consist of fine α-Al cells containing uniformly dispersed silicon nanoparticles, which are, in addition, surrounded by a eutectic Si network. Above 260°C the silicon interconnectivity starts to breakdown into spheroidized particles and to coarsen. At the same time, the heating residual stresses are relieved.
The objective of the contribution is to investigate, under different heat treatment conditions, the evolution of microstructure and residual stresses in view of optimizing the fatigue performance of the alloy. To this purpose various heat treatments in a range of temperatures between 265°C and 300°C for a duration between 15 minutes and 2 hours are performed. The microstructure modifications are analysed using a scanning electron microscope and the residual stress state is measured by laboratory X-ray diffraction.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - AlSi10Mg alloy
KW - Additive manufacturing
KW - L-PBF
KW - Residual stress
KW - Heat treatment
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544942
DO - https://doi.org/10.1016/j.prostr.2022.03.057
SN - 2452-3216
VL - 38
SP - 564
EP - 571
PB - Elsevier B.V.
AN - OPUS4-54494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Villajos, José Antonio
A1 - Feldmann, Ines
A1 - Emmerling, Franziska
T1 - Mix and wait – a relaxed way for synthesizing ZIF-8
N2 - Herein we report the synthesis of a zeolitic imidazolate framework (ZIF-8) by an easy “mix and wait” procedure. In a closed vial, without any interference, the mixture of 2-methylimidazole and basic zinc carbonate assembles into the crystalline product with approx. 90% conversion after 70 h. The reaction exhibits sigmoidal kinetics due to the self-generated water which accelerates the reaction.
KW - In-situ analysis
KW - Mechanochemistry
KW - MOF
KW - Synthesis
KW - ZIF-8
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546841
DO - https://doi.org/10.1039/D2RA00740A
VL - 12
SP - 8940
EP - 8944
PB - Royal Society of Chemistry
AN - OPUS4-54684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Werner, Tiago
T1 - Estimation of the Kitagawa-Takahashi diagram by cyclic R curve analysis
N2 - The Kitagawa-Takahashi (KT) diagram is a proven concept for describing the fatigue limit in presence of a defect or crack. It can be determined empirically with great experimental effort. It can also be estimated by means of the El Haddad relationship if the endurance limit and the long fatigue crack propagation threshold are available in reasonable accuracy. A third option is the determination using the cyclic R-curve, which describes the dependency of the fatigue crack propagation threshold on the crack growth at the short crack propagation stage. This can be experimentally determined using a closure-free initial pre-crack. It can then be applied to the determination of crack arrest for a given applied load and a given defect or crack size. Compared to the other two methods mentioned above, this option has considerable advantages: It can be applied to any component and any stress ratio. It allows the treatment of multiple cracks and provides estimations of the S-N curve in the finite life regime as well as at the endurance limit. Compared to the empirical determination of the KT diagram, the experimental effort is significantly lower and compared to the El Haddad approach it avoids problems such as the use of non-conservative long fatigue crack propagation thresholds (when the conventional load reduction method is applied to materials prone to corrosion) and the mathematical predetermination of the curve shape. The work introduces the method and provides a critical discussion as well as quantitative comparison between the different methods.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue life
KW - Endurance limit
KW - Kitagawa-Takahashi diagram
KW - Cyclic R-curve
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544931
DO - https://doi.org/10.1016/j.prostr.2022.03.032
SN - 2452-3216
VL - 38
SP - 309
EP - 316
PB - Elsevier B.V.
AN - OPUS4-54493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kempf, Andreas
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Hilgenberg, Kai
T1 - Correlation between quasistatic und fatigue properties of additively manufactured AlSi10Mg using Laser Powder Bed Fusion
N2 - In order to find a resource efficient approach for the fatigue lifetime prediction of laser powder bed fusion (L-PBF) processed AlSi10Mg material, results of tensile and fatigue tests were compared. The specimens were manufactured with three different L-PBF machines and studied in different heat treatment conditions (as-built, annealed, T6 heat treated). The investigations showed that the high attainable tensile strength properties after the manufacturing process are not beneficial in the high cycle fatigue (HCF) regime. In contrast, the applied heat treatments, which lead typically to a decrease of ultimate tensile strength, improved dramatically the fatigue behavior. Additionally, a clear correlation between the elongation at fracture and HCF resistance has been found for individual heat treatment conditions. This empiric relationship provides an estimation of the fatigue resistance in the presence of material defects and can be implemented in part and process approvals.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Additive Manufacturing
KW - Laser powder bed fusion
KW - AlSi10Mg
KW - Tensile properties
KW - Fatigue properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544921
DO - https://doi.org/10.1016/j.prostr.2022.03.009
SN - 2452-3216
VL - 38
SP - 77
EP - 83
PB - Elsevier B.V.
AN - OPUS4-54492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Fedelich, Bernard
A1 - Jokisch, T.
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Fatigue and fracture in dual-material specimens of nickel-based alloys fabricated by hybrid additive manufacturing
N2 - The integration of additive manufacturing with traditional processes, termed hybrid additive manufacturing, has expanded its application domain, particularly in the repair of gas turbine blade tips. However, process-related defects in additively manufactured materials, interface formation, and material property mismatches in dual-material structures can significantly impact the fatigue performance of components. This investigation examines the low cycle fatigue and fatigue crack growth behaviors in dual-material specimens of nickel-based alloys, specifically the additively manufactured STAL15 and the cast alloy 247DS, at elevated temperatures. Low cycle fatigue experiments were conducted at temperatures of 950 °C and 1000 °C under a range of strain levels (0.3%–0.8%) and fatigue crack growth tests were conducted at 950 °C with stress ratios of 0.1 and −1. Fractographic and microscopic analyses were performed to comprehend fatigue crack initiation and crack growth mechanisms in the dual-material structure. The results consistently indicated crack initiation and fatigue fracture in the additively manufactured STAL15 material. Notably, fatigue crack growth retardation was observed near the interface when the crack extended from the additively manufactured STAL15 material to the perpendicularly positioned interface. This study highlights the importance of considering yield strength mismatch, as well as the potential effects of residual stresses and grain structure differences, in the interpretation of fatigue crack growth behavior at the interface.
KW - Hybrid additive manufacturing
KW - Dual-material nickel-based alloys
KW - High-temperature fatigue crack growth
KW - Low cycle fatigue
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609340
DO - https://doi.org/10.1016/j.jmrt.2024.08.211
SN - 2238-7854
VL - 32
SP - 3737
EP - 3749
PB - Elsevier B.V.
AN - OPUS4-60934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Bhatia, Riya
A1 - Dey, R.
A1 - Falkenhagen, Jana
A1 - Ullrich, M. S.
A1 - Thomsen, C.
A1 - Schartel, Bernhard
T1 - Wastewater phosphorus enriched algae as a sustainable flame retardant in polylactide
N2 - Revolutionizing our polymer industry for adaption to a sustainable carbon circular economy has become one of today’s most demanding challenges. Exploiting renewable resources to replace fossil-fuel—based plastics with biopolymers such as poly(lactic acid) (PLA) is inevitable while using waste streams as a raw material resource at least is promising. When it comes to using PLA as technical polymer, its high flammability must be addressed by flame retardants compatible with the thermoplastic processing of PLA and its compostability. This study proposes microalgae enriched with phosphorus from wastewater (P-Algae) as an elegant way towards a kind of sustainable organophosphorus flame retardant. The concept is demonstrated by investigating the processing, pyrolysis, flammability, and fire behavior of PLA/P-Algae, while varying the P-Algae content and comparing P-Algae with four alternative bio-fillers (phosphorylated lignin, biochar, thermally treated sewage sludge, and metal phytate) with different P-contents as meaningful benchmarks.
KW - PLA
KW - Flame Retardancy
KW - Phosphorylated Algae
KW - Wastewater flame retardants
KW - Zink phytate
KW - Phosphorylated lignin
KW - Thermally treated sludge
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604150
DO - https://doi.org/10.1016/j.polymdegradstab.2024.110885
SN - 1873-2321
SN - 0141-3910
VL - 227
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-60415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rashidi, Reza
A1 - Riechers, Birte
A1 - Rosalie, Julian
A1 - Maaß, Robert
T1 - Annealing-dependent elastic microstructure in a Zr-based metallic glass
N2 - In this letter, we demonstrate the robust presence of an elastic microstructure in a Zr-based metallic glass (MG) with a characteristic length-scale of the order of 100 nm. This length scale increases systematically towards the MG surface in differently sized casts, whereas thermal relaxation homogenizes both the internal length-scale gradient and the magnitude of the elastic fluctuations. Strongest changes during relaxation arise in the stiffest parts of the elastic microstructure. These findings indicate that the elastic microstructure emerges due to cooling constraints and may therefore be a microstructural manifestation of the internal residual stresses that arise during MG-solidification.
KW - Metallic glass
KW - Heterogeneity
KW - Elastic microstructure
KW - Nanoindentation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610962
DO - https://doi.org/10.1016/j.scriptamat.2024.116380
VL - 255
SP - 1
EP - 5
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-61096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Haubrich, Jan
A1 - Requena, Guillermo
A1 - Madia, Mauro
T1 - Investigation on the fatigue strength of AlSi10Mg fabricated by PBF-LB/M and subjected to low temperature heat treatments
N2 - This work provides an investigation of the influence of low temperature heat treatments on the fatigue behavior of a PBF-LB AlSi10Mg alloy. Fatigue specimens are produced in form of round bars on a build platform preheated at 200 ◦C. The specimens have been tested in three different conditions: as-built, and after heat treatments at 265 ◦C for 1 h and 300 ◦C for 2 h. Prior to the fatigue testing, the defect distribution is analyzed by means of micro computed tomography. Subsequently, the peak over threshold method is successfully applied to provide a prediction of the size of killer defect. The defect population was of gas porosity type. No clear improvement of the fatigue performance is observed after the heat treatments. The fatigue strength predicted using fracture mechanics-based approaches is in good agreement with the experimental data. Among the studied approaches, short crack models provided the most conservative predictions.
KW - PBF-LB/M AlSi10Mg
KW - Fatigue strength
KW - Defects
KW - Kitagawa-Takahashi Diagram
KW - Short Crack Models
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607071
DO - https://doi.org/10.1016/j.matdes.2024.113170
SN - 0264-1275
VL - 244
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-60707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Bauer, Felix
A1 - Uhlemann, Patrick
A1 - Thärig, Steffen
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
T1 - Mechanical testing dataset of cast copper alloys for the purpose of digitalization
N2 - This data article presents a set of primary, analyzed, and digitalized mechanical testing datasets for nine copper alloys. The mechanical testing methods including the Brinell and Vickers hardness, tensile, stress relaxation, and low-cycle fatigue (LCF) testing were performed according to the DIN/ISO standards. The obtained primary testing data (84 files) mainly contain the raw measured data along with the testing metadata of the processes, materials, and testing machines. Five secondary datasets were also provided for each testing method by collecting the main meta- and measurement data from the primary data and the outputs of data analyses. These datasets give materials scientists beneficial data for comparative material selection analyses by clarifying the wide range of mechanical properties of copper alloys, including Brinell and Vickers hardness, yield and tensile strengths, elongation, reduction of area, relaxed and residual stresses, and LCF fatigue life. Furthermore, both the primary and secondary datasets were digitalized by the approach introduced in the research article entitled “Toward a digital materials mechanical testing lab” [1]. The resulting open-linked data are the machine-processable semantic descriptions of data and their generation processes and can be easily queried by semantic searches to enable advanced data-driven materials research.
KW - FAIR principles
KW - Hardness
KW - Low-Cycle Fatigue (LCF)
KW - Tensile testing
KW - Stress relaxation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605005
DO - https://doi.org/10.1016/j.dib.2024.110687
SN - 2352-3409
SP - 1
EP - 15
PB - Elsevier BV
AN - OPUS4-60500
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madkour, Sherif
A1 - Garwek, Marcel
A1 - Hertwig, Andreas
A1 - Schönhals, Andreas
T1 - Do Interfacial Layers in Thin Films Act as an Independent Layer Within Thin Films?
N2 - The thermodynamic behavior of thin PVME films including the irreversible adsorbed layer on the substrate is investigated. In a first step, the growth kinetics of the adsorbed layer was studied combining a leaching technique and atomic force microscopy. Further, it was shown that there is a critical initial film thickness for the formation of a surface-filling adsorbed layer. Additionally, spectroscopic ellipsometry measurements were carried out to investigate the influence of the adsorbed layer on the glass transition temperature of the thin films. For 30 nm films and below, the influence of the adsorbed layer percolates strongly to the bulk-like layer of the film. Finally, the molecular dynamics of the adsorbed layer was studied by broadband dielectric spectroscopy, employing nanostructured-electrode systems. One process was revealed, which was assigned either to molecular fluctuations taking place in a loosely-bounded the part of the adsorbed layer, or to the desorption/adsorption of segments at the substrate.
KW - Thin polymer films
PY - 2021
DO - https://doi.org/10.1021/acs.macromol.0c02149
VL - 54
IS - 1
SP - 509
EP - 519
PB - ACS Publications
AN - OPUS4-52037
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
A1 - Scheuschner, Nils
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Maierhofer, Christiane
T1 - Towards the determination of real process temperatures in the LMD process by multispectral thermography
N2 - Due to the rapid thermal cycles involved in additive manufacturing of metals, high internal stresses and peculiar microstructures occur, which influence the parts mechanical properties. To systematically examine their formation, in-process measurements of the temperature are needed. Since the part emissivity is strongly inhomogeneous and rapidly changing in the process, the applicability of thermography for the determination of thermodynamic temperatures is limited. Measuring the thermal radiation in different wavelengths simultaneously, temperature and emissivity can be separated. Here, we present results of a preliminary study using multispectral thermography to obtain real temperatures and emissivities in directed energy deposition (DED) processes.
T2 - Thermosense: Thermal Infrared Applications XLIII
CY - Online meeting
DA - 12.04.2021
KW - Additive Manufacturing
KW - Process monitoring
KW - Multispectral thermography
KW - Laser metal deposition
KW - TES
KW - LMD
KW - Temperature emissivity separation
PY - 2021
DO - https://doi.org/10.1117/12.2587881
VL - 2021
SP - 77
EP - 83
PB - SPIE
AN - OPUS4-52516
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strauß, Lea
T1 - Empirical Model for Fatigue Life Prediction
N2 - Laser-based powder bed fusion (PBF-LB) is an advanced additive manufacturing technique renowned for its precision and capability to fabricate complex metal components. However, the high thermal gradients and rapid cooling rates intrinsic to this process introduce significant process-induced effects, such as inhomogeneities, surface roughness, anisotropy, and residual stress, all of which critically influence the fatigue behavior of the produced parts. This study investigates the fatigue performance of AlSi10Mg samples produced by PBF-LB, examining the impact of varying surface conditions, geometries, and residual stress levels. Fatigue life prediction models are formulated based on nominal stress amplitude, residual stress, notch factor, crackinitiating inhomogeneity, and surface roughness, with smooth samples serving as a baseline reference. The study presents two empirical models for predicting fatigue life and fatigue strength using S-N curves and the Kitagawa-Takahashi diagram with the El Haddad approach, derived from comprehensive experimental data, including finite element modelling, fatigue life measurements, surface roughness evaluations, and residual stress analysis.
T2 - ICAM2024
CY - Atlanta, GA, USA
DA - 28.10.2024
KW - AlSi10Mg
KW - Kitagawa-Takahashi diagram
KW - Equivalent stress
KW - Fatigue life prediction
KW - PBF-LB/M
PY - 2024
AN - OPUS4-61538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Low cycle fatigue behavior of DED-L Ti-6AL-4V
N2 - Laser powder-based directed energy deposition (DED-L) is a technology that offers the possibility for 3D material deposition over hundreds of layers and has thus the potential for application in additive manufacturing (AM). However, to achieve broad industrial application as AM technology, more data and knowledge about the fabricated materials regarding the achieved properties and their relationship to the manufacturing process and the resulting microstructure is still needed. In this work, we present data regarding the low-cycle fatigue (LCF) behavior of Ti-6Al-4V. The material was fabricated using an optimized DED-L process. It features a low defect population and excellent tensile properties. To assess its LCF behavior two conventionally manufactured variants of the same alloy featuring different microstructures were additionally tested. The strain-controlled LCF tests were carried out in fully reversed mode with 0.3 % to 1.0 % axial strain amplitude from room temperature up to 400°C. The LCF behavior and failure mechanisms are described. For characterization, optical microscopy (OM), scanning electron microscopy (SEM), and micro-computed tomography (µCT) were used. The low defect population allows for a better understanding of the intrinsic material’s properties and enables a fairer comparison against the conventional variants. The fatigue lifetimes of the DED-L material are nearly independent of the test temperature. At elevated test temperatures, they are similar or higher than the lifetimes of the conventional counterparts. At room temperature, they are only surpassed by the lifetimes of one of them. The principal failure mechanism involves multiple crack initiation sites.
T2 - Ninth International Conference on Low Cycle Fatigue (LCF9)
CY - Berlin, Germany
DA - 21.06.2022
KW - AGIL
KW - Additive Manufacturing
KW - Ti-6Al-4V
KW - Low-Cycle-Fatigue
KW - Microstructure
PY - 2022
AN - OPUS4-55123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Ökobilanzierung schweißtechnischer Fertigungsverfahren - Methodik, Einflussgrößen und Implementierung
N2 - Ein wesentliches Ziel der deutschen Industriepolitik besteht darin, Rahmenbedingungen zu schaffen, welche die Positionierung nachhaltiger Produkte und Prozesse innerhalb globaler Wertschöpfungsketten ermöglichen und ökoeffiziente Fertigungsprozesse langfristig sichern. In diesem Beitrag werden aktuelle Forschungsarbeiten zur Bewertung der Umweltwirkungen der schweißtechnischen Fertigungskette anhand ausgewählter Schmelzschweißverfahren unter Berücksichtigung vor- sowie nachgelagerter Fertigungsschritte dargestellt. Eine weit verbreitete und standardisierte Methode zur Abschätzung der Umweltwirkungen eines Produkts oder Prozesses ist die Ökobilanzierung. Hierbei stellen die Sachbilanzierung, das heißt die Ermittlung sämtlicher relevanter Energie- und Ressourcenverbräuche während der schweißtechnischen Fertigung, aufgrund des hohen Dokumentationsaufwands, sowie die Ableitung assoziierter Wirkkategorien das größte Hindernis für eine Etablierung und Akzeptanz der Ökobilanzierung in der Praxis dar. Gleichwohl wird seitens Unternehmen, welche als Zulieferer von OEM’s (engl.: original equipment manufacturer) agieren, die Dokumentation des fertigungsspezifischen CO2-Verbrauches gefordert. Ein weiterer Aspekt der Arbeiten beinhaltet Methoden zur automatisierten Erfassung von schweißtechnischen Produktionsdaten sowie deren Nachverfolgbarkeit. Anhand unterschiedlicher Schweißverfahren werden die aus den Produktionsdaten abgeleiteten Energie- und Ressourcenverbräuche automatisiert in die relevanten Umweltwirkungen überführt. Die analysierten Schweißprozesse umfassen dabei ein breites für kleine und mittlere Unternehmen (KMU) relevantes Spektrum. Durch die softwareseitige Bereitstellung der aufgestellten Umweltprofile ist der Anwender in der Lage, Schweißprozesse unter ökologischen Aspekten zu bewerten und die effizienteste Variante zu identifizieren.
T2 - Woche der Fügetechnik 2022, HWK Münster
CY - Online meeting
DA - 30.11.2022
KW - Ökobilanzierung
KW - Verfahrensvergleich
KW - Schweißprozesse
KW - Umweltwirkungen
KW - Implementierung
PY - 2022
AN - OPUS4-56650
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Gesell, Stephan
A1 - Fedelich, Bernard
A1 - Rehmer, Birgit
A1 - Uhlemann, Patrick
A1 - Skrotzki, Birgit
A1 - Ganesh, R.
A1 - Dude, D. P.
A1 - Kuna, M.
A1 - Kiefer, B.
T1 - TMF-Rissverlaufsberechnung für ATL-Heißteile
N2 - Die Steigerung der Leistung und des thermodynamischen Wirkungsgrades von Verbrennungsmotoren führt zu erhöhten Anforderungen an die Festigkeit abgasführender Komponenten wie z. Bsp. Abgasturbolader. Als Folge erhöhter thermomechanischer Wechselbeanspruchungen (TMF) im Betrieb kommt es an den mechanisch und/oder thermisch höchst beanspruchten Stellen der Bauteile zur Bildung von Rissen, wodurch die Lebensdauer der Komponenten begrenzt wird. Derzeit werden bei Turboladern heißgehende Bauteile mit detektierten Rissen zumeist prophylaktisch ersetzt, da die weitere Ausbreitung der Risse während des Betriebs nicht vorhergesagt werden kann. Um diese aufwändige und un- ökonomische Praxis zu vermeiden, wurde im vorliegenden Forschungsvorhaben eine rechnerische Bewertungsmethode auf Basis der experimentellen und numerischen Bruchmechanik erarbeitet, mit deren Hilfe bereits in der Auslegungsphase oder während des Betriebs die (restliche) Lebensdauer der abgasführenden Komponenten vorhergesagt werden kann. Damit wird erstmalig die quantitative Vorhersage der Rissentwicklung bei TMF-Beanspruchungsbedingungen unter Berücksichtigung großer zyklischer viskoplastischer Verformungen ermöglicht.
Zentrales Ergebnis des Vorhabens ist eine automatisierte Berechnungsprozedur auf der Basis spezieller Finite-Elemente-Techniken (FEM), womit sowohl der Pfad als auch die Größe eines Risses als Funktion der Anzahl der Lastwechsel in Bauteilen unter TMF-Bedingungen berechnet werden kann. Als geeigneter Beanspruchungsparameter zur Bewertung des Rissfortschritts unter TMF wurde die zyklische Rissöffnungsverschiebung ΔCTOD verwendet. Das Werkstoffverhalten des betrachteten austenitischen Gusseisens Ni-Resist D-5S wurde mit einem validierten viskoplastischen, temperaturabhängigen Materialmodell modelliert, das zur Berücksichtigung große Verzerrungen und Rotationen am Riss erweitert wurde. Für die genaue Berechnung des ΔCTOD bei TMF wurden effiziente FEM-Techniken erarbeitet. Zur Simulation der Rissausbreitung wurde ein automatischer FEM-Algorithmus mit inkrementeller adaptiver Neuvernetzung entwickelt, bei dem die Verformungen und inelastischen Zustandsvariablen jeweils vom alten auf das neue Netz übertragen werden. Dieser Algorithmus wurde im Software-Paket ProCrackPlast implementiert, das in Verbindung mit dem kommerziellen FEM-Code Abaqus zur Lösung dreidimensionaler Rissprobleme zur Verfügung steht. Ziel der umfangreichen experimentellen Arbeiten war es, an isothermen LCF und anisothermen TMF-Versuchen mit gekerbten Flachzugproben (SENT) das Risswachstum im Temperaturbereich von 20 °C bis 700 °C zu ermitteln. Mit Hilfe begleitender 2D FEM Simulationen wurden anhand dieser Datenbasis die Rissfortschrittskurven des Werkstoffs unter Anwendung des ΔCTOD-Konzepts bestimmt und in geeigneter, parametrisierter Form den Nutzern zur Verfügung gestellt. Die Versuche an SENT-Proben wurden mit der entwickelten Software ProCrackPlast als 3D Modell simuliert. Der Vergleich der 2D und 3D Simulationen ergab einen systematischen Unterschied im CTOD und CTOD, der mit Hilfe eines Übertragungsfaktors korrigiert wurde. Der Vergleich der 3D Berechnungen mit den Experimenten zeigte eine zufriedenstellende Übereinstimmung der er- reichten Risslänge mit der Zahl der Lastzyklen im gesamten Temperaturbereich, wobei die numerische Prognose meist auf der konservativen / sicheren Seite lag. Die Übertragbarkeit der Ergebnisse der 2D Parameteridentifikation auf 3D Risskonfigurationen mit Mixed-Mode Beanspruchung ist mit zusätzlichen Versagenshypothesen verbunden, die aufgrund fehlender Versuchsdaten im Vorhaben nicht endgültig geklärt werden konnten. Zur Validierung des Gesamtkonzeptes wurden LCF-Proben mit einem bauteil- typischen Oberflächenriss experimentell und numerisch untersucht. In der Simulation konnte die komplexe Form und Größe der Rissentwicklung zufriedenstellend (richtig) vorhergesagt werden. Die Leis- tungsfähigkeit der erarbeiteten rechnerische Bewertungsmethode wurde an weiteren TMF-Beispielen vorgestellt und diskutiert. Die Software ProCrackPlast und die viskoplastische Materialroutine wurden dem Anwenderkreis des Vorhabens zusammen mit einem Nutzer-Handbuch und Verifikationsbeispielen zur Verfügung gestellt.
Das Ziel des Forschungsvorhabens ist erreicht worden.
KW - Abgasturbolader Heißteile
KW - Numerische Simulation
KW - Rissverlauf
PY - 2023
VL - 1320
SP - 1
EP - 137
PB - Forschungsvereinigung Verbrennungskraftmaschinen (FVV)
CY - Frankfurt am Main
AN - OPUS4-56960
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Creep Behavior of Stainless Steel 316L Manufactured by Laser Powder Bed Fusion
N2 - This contribution presents the results of an experimental study on the creep behavior of an austenitic 316L stainless steel produced by laser powder bed fusion (PBF-LB/M/316L) with an emphasis on understanding the effects of microstructure on the creep mechanisms. Hot tensile tests and constant force creep tests at 600 °C and 650 °C, X-ray computed tomography, as well as optical and electron microscopy were performed. The produced PBF-LB/M/316L exhibits a low void population (< 0.01 %) resulting from the manufacturing parameters used and which allowed us to understand the effects of other microstructural aspects on creep behavior, e.g., grain morphology and dislocation substructure. A hot‑rolled variant of 316L was also tested as a reference.
T2 - International Materials Science and Engineering Congress - MSE 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - AGIL
KW - Additive Fertigung
KW - Mikrostruktur
KW - Mikrostrukturentwicklung
KW - Kriechen
KW - Kriechschädigung
PY - 2024
AN - OPUS4-61169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Two-colour thermography for measurement of temperature distribution in laser beam welding
N2 - Solidification cracking is a frequently observed phenomenon in laser beam welding of austenitic stainless steels and other metallic alloys. Characterisation of cracking susceptibility requires knowledge of the precise and spatially resolved temperature distribution near the solidification front in the welding process. Thermography is a standard tool that provides a qualitative estimate of the 2D temperature field. The general disadvantage of this method is its dependence on the emission characteristics of the measured object. For welding applications, these can vary significantly in the temperature range above and below the melting temperature. For this purpose, we have developed a thermography-based measurement technique using a SWIR camera system in combination with two narrow bandpass filters that use the principle of two-wavelength pyrometry to estimate absolute temperature values. This technique was used to determine the temperature distributions and gradients near the solidification front of laser-welded austenitic steel. The results were validated by other measurements.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 16.09.2024
KW - Laser beam welding
KW - Solidification cracking
KW - FEM simulation
PY - 2024
AN - OPUS4-62415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Phonon-accurate machine-learning potentials from automated workflows
N2 - Data-driven materials design aims to predict and optimize material properties, such as stability and thermal conductivity, which are influenced by vibrational behavior. Approaches like DFT are computationally demanding and have limitations for phonon calculations. Machine learning-driven interatomic potentials (MLIP), like the Gaussian approximation potential (GAP), offer a more efficient alternative.1–8 We developed a Python workflow to automate MLIP generation using the Materials Project database.9 DFT computations, MLIP fitting and benchmark steps are automated.10,11 This approach accelerates phonon calculations and supports testing different data generation strategies and hyperparameters, and further validation12 is planned. Our goal is to provide open-source code and share these potentials.
T2 - Faraday Discussions: Data-driven discovery in the chemical sciences
CY - Oxford, UK
DA - 10.09.2024
KW - Interatomic potentials
KW - Machine learning
KW - Phonons
KW - Thermoelectrics
PY - 2024
AN - OPUS4-61061
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Bustamante, Joana
A1 - Naik, Aakash
A1 - Ueltzen, Katharina
A1 - George, Janine
A1 - Ertural, Christina
T1 - Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study. DFT-part
N2 - This repository contains computational data supporting the manuscript titled *“Thermal Transport in Ag8TS6 (T= Si, Ge, Sn) Argyrodites: An Integrated Experimental, Quantum-Chemical, and Computational Modelling Study”* It includes raw data for vibrational properties, elastic properties and Bonding analysis.
KW - DFT
KW - QHA
KW - Lattice thermal conductivity
KW - Grüneisen parameter
PY - 2025
DO - https://doi.org/10.5281/zenodo.17399975
PB - Zenodo
CY - Geneva
AN - OPUS4-64671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Jokisch, T.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Effects on crack formation of additive manufactured Inconel 939 sheets during electron beam welding
N2 - The potential of additive manufacturing for processing precipitation hardened nickel-base superalloys, such as Inconel 939 is considerable, but in order to fully exploit this potential, fusion welding capabilities for additive parts need to be explored. Currently, it is uncertain how the different properties from the additive manufacturing process will affect the weldability of materials susceptible to hot cracking. Therefore, this work investigates the possibility of joining additively manufactured nickel-based superalloys using electron beam welding. In particular,
the influence of process parameters on crack formation is investigated. In addition, hardness measurements are performed on cross-sections of the welds. It is shown that cracks at the seam head are enhanced by Welding speed and energy per unit length and correlate with the hardness of the weld metal. Cracking parallel to the weld area shows no clear dependence on the process variables that have been investigated, but is related to the hardness of the heat-affected zone.
KW - Electron beam welding
KW - Hot Cracks
KW - Superalloy
KW - Inconel 939
PY - 2021
DO - https://doi.org/10.1016/j.vacuum.2021.110649
SN - 0042-207X
VL - 195
SP - 10649
PB - Elsevier Ltd.
AN - OPUS4-53689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
T1 - Life cycle assessment of fusion welding processes considering upstream and downstream process steps
N2 - In manufacturing, fusion welding processes consume significant resources, presenting a significant opportunity for reducing environmental impact. Although there is a qualitative understanding of the environmental implications of these processes, a quantitative assessment of key parameters remains complex. This study introduces a welding-specific methodology that employs life cycle assessment (LCA) to quantitatively evaluate the environmental footprint of fusion welding technologies. Our approach identifies and analyses the principal parameters affecting the environmental performance of various welding techniques, including traditional joint welding and additive manufacturing via the Direct Energy Deposition-Arc (DED-Arc) process. Real-time resource usage data is integrated to offer an innovative framework for directly deriving environmental impacts. This research contributes to optimising welding processes by providing a precise and quantifiable measure of their ecological impact. This facilitates the advancement of sustainable manufacturing practices.
T2 - Joining Smart Technologies - International Automotive Conference
CY - Wels, Austria
DA - 10.05.2023
KW - Life Cycle Assessment
KW - Arc welding
KW - Additive manufacturing
KW - DED-Arc
PY - 2023
AN - OPUS4-59494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abel, Andreas
T1 - Ambient and high-temperature mechanical properties of intermetallic Fe3Al alloys with complex borides
N2 - Due to the increasing scarcity of critical raw materials current high-temperature materials are sought to be replaced by alloys based on more abundant metals. One possibility within the class of intermetallics are iron aluminides, which combine sustainability and cost-efficiency with the prospect of mass savings. Iron aluminides show competitive specific strength up to 700 °C and excellent creep and wet corrosion resistance by small additions of Mo, Ti and B. Nevertheless, a Mo content of above 2 at.% which is needed for optimum corrosion resistance results in enhanced brittleness, especially at room temperature. This is why alloys with these Mo fractions were only mechanically tested under compressive loading so far. Still, testing of static and creep properties under tensile loading is required for reliable component design. Besides high standards for crack-free processing, data acquisition for tensile loads is especially complicated by environmental embrittling effects for iron aluminides. To cope with these challenges, the AiF research project “WAFEAL – Materials applications for iron aluminides” was initiated. The main goal is to collect standardised data on ambient and high-temperature tensile properties and creep properties. Samples with a nominal composition of Fe-26Al-4Mo-0.5Ti-1B [at.%] were manufactured via centrifugal casting in ceramic shell moulds followed by machining. Heat treatment for homogenisation and final polishing were carried out where appropriate. A summary of the achieved tensile and creep properties such as yield and tensile strength, maximum elongation, secondary creep rate and stress exponents will be given. Results will be also discussed regarding the influence of temperature, stress level and microstructure on the damage mechanisms. Furthermore, the effect of different alloy concentrations on the mechanical response at different temperatures will be outlined within a small experimental series.
T2 - MSE Congress 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Fe-Al alloys
KW - Intermetallics
KW - Iron aluminides
KW - Tensile data
KW - High temperature mechanical properties
KW - Creep data
KW - Fractography
PY - 2022
AN - OPUS4-55993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - Multi-Layer welding data analysis and open data approach using WelDX
N2 - The talk motivates and introduces the WelDX project and the proposed solutions for current challenges in the field of research data management and Open Science practices in welding research.
Using an exemplary welding dataset based on the joint and welding process design of offshore structures, advanced data fusion and analysis capabilities are demonstrated.
The dataset shown consists of a complex welding sequence covering multiple weld layers with varying process parameters and adaptive weaving motions to cover manufacturing tolerances. In the presentation, an interactive exploration of the dataset contents in the spatial domain is presented. Furthermore, transformation between spatial and time domain of the data is demonstrated.
In addition to data gathered during the welding process, the integration of downstream testing data and results is also explained. For demonstration, integration of weld seam cross section images and Vickers hardness mapping test results into the dataset are explained an demonstrated. The testing data is set into context with the welding process information.
Finally, implications for advancements in research data management for WAAM and AI applications are discussed.
T2 - The 75th IIW Annual Assembly and International Conference
CY - Tokyo, Japan
DA - 17.07.2022
KW - WelDX
KW - Research data management
KW - Open science
KW - Arc welding
KW - Digital transformation
PY - 2022
AN - OPUS4-55354
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - VIDEO
A1 - George, Janine
T1 - Materials design using chemical heuristics, workflows, and machine learning
N2 - Bonds and local atomic environments are key descriptors of material properties, used to establish design rules and heuristics, and serve as descriptors in machine-learned interatomic potentials and the general machine learning of material properties.
Software implementations such as ChemEnv and LobsterEnv identify local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis (here using Crystal Orbital Hamilton Populations as computed with LOBSTER). Fully automated workflows and analysis tools now enable large-scale quantum-chemical bonding analysis. The first part of the lecture will demonstrate how these tools help develop new machine-learning models and intuitive understandings of material properties.
New universal machine-learned interatomic potentials, such as MACE-MP-0, have been developed. The second part of the lecture will showcase how these potentials, combined with DFT, can accelerate research. It will focus on the interplay between DFT and machine-learned interatomic potentials, presenting automated workflows for training, fine-tuning, and benchmarking these potentials, implemented in our software autoplex. Additionally, it will show how to train new interatomic potentials from scratch by exploring potential energy surfaces, with the potential to enhance current universal machine-learned potentials.
The lecture will also discuss the trend toward automation in computational materials science and our recent contributions.
T2 - FAIRmat Seminar
CY - Berlin, Germany
DA - 05.06.2025
KW - Materials Design
KW - Machine Learning
KW - Chemical Bonding
KW - Batteries
KW - Amorphous Materials
KW - Workflows
KW - Machine Learned Interatomic Potentials
KW - Phonons
KW - Magnetism
KW - Synthesizability
PY - 2025
UR - https://www.youtube.com/watch?v=Sfco48s1fpU
PB - YouTube, LLC
CY - San Bruno, CA, USA
AN - OPUS4-63744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Su, C.
A1 - Shi, J.
A1 - Durlo Tambara, Luís Urbano
A1 - Yang, Y.
A1 - Liu, B.
A1 - Revilla-Cuesta, V.
T1 - Improving the mechanical properties and durability of steam-cured concrete by incorporating recycled clay bricks aggregates from C&D waste
N2 - The output of C&D waste is increasing year by year, among which low-quality recycled brick aggregates (RBAs) have not been well utilized and brought environmental burden. The durability of steam-cured concrete (HCC) is often compromised due to the detrimental effects of this curing regime on the long-term performance and microstructure development of the concrete material. To address this issue, this study investigates the potential of incorporating RBAs to improve the long-term durability of HCC. The results demonstrate that the incorporation of a small amount of RBA (10–20%) not only enhances the 28-d strength of HCC by 2.5–11.3%, but also improves its impermeability by mitigating heat damage effects. The combined application of fine and coarse RBA was found to effectively balance the negative effects of coarse RBA on the performance of HCC. Furthermore, the utilization of RBA in HCC was shown to have economic and environmental benefits. The results of this study demonstrate a simple and effective approach to improve the long-term durability of HCC while promoting the high-value utilization of solid waste.
KW - Steam-cured concrete
KW - C&D waste
KW - Durability
KW - Recycled aggregate
KW - Environmental benefits
PY - 2024
DO - https://doi.org/10.1016/j.powtec.2024.119571
VL - 438
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-59799
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX - a file format for processing and archiving welding research data
N2 - The talk gives an introduction into gas metal arc welding and its relation to plasma science as well as current challenges in welding research concerning research data management and the application of the FAIR principles.
The WelDX project is introduced and the main goals are discussed and contrasted with the current features of the weldx API.
Different internal and public facing use cases focusing on research data management and their implementation using weldx are presented.
The interactive part of the presentation displays some advanced multi layer use cases and data analysis using the weldx API as well as the integration of materials properties into weldx.
T2 - International Workshop on FAIR Data in Plasma Science
CY - Online meeting
DA - 16.05.2022
KW - WelDX
KW - Open science
KW - Research data management
KW - Arc welding
KW - Digital transformation
PY - 2022
AN - OPUS4-55153
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX – progress report on the welding data exchange format
N2 - The presentation shows the current development status of the Welding Data Exchange (weldx) format based on the Advanced Scientific Data Format (ASDF).
The use of a complete single pass arc welding experiment example stored in a single weldx file and validated against a predefined schema definition is presented.
The example includes generic experimental metadata, the workpiece geometry and materials definition following associated standards, the weld process spatial movement description, the welding process parameter descriptions and welding process measurements. The inclusion of 3D scan data of the workpiece description is also included.
The full code and data is available on GitHub: https://github.com/BAMWelDX/IIW2021_AA_CXII
T2 - 2021 IIW Annual Assembly and International Conference on welding and Joining
CY - Online meeting
DA - 07.07.2021
KW - Arc welding
KW - Digitalization
KW - Open science
KW - Research data management
KW - WelDX
PY - 2021
AN - OPUS4-53401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jürgens, Maria
A1 - Sonntag, Nadja
A1 - Olbricht, Jürgen
A1 - Fedelich, Bernard
A1 - Skrotzki, Birgit
T1 - The effect of dwell times on the thermomechanical fatigue life performance of grade P92 steel at intermediate and low strain amplitudes
N2 - Results of an extended TMF test program on grade P92 steel in the temperature range of 620 °C - 300 °C, comprising in-phase (IP) and out-of-phase (OP) tests, partly performed with symmetric dwells at Tmax/Tmin, are presented. In contrast to previous studies, the low-strain regime is also illuminated, which approaches flexible operation in a power plant with start/stop cycles. At all strain amplitudes, the material performance is characterized by continuous cyclic softening, which is retarded in tests at lower strains but reaches similar magnitudes in the course of testing. In the investigated temperature range, the phase angle does not affect fatigue life in continuous experiments, whereas the IP condition is more detrimental in tests with dwells. Fractographic analyses indicate creep-dominated and fatigue-dominated damage for IP and OP, respectively. Analyses of the (micro)hardness distribution in the tested specimens suggest an enhanced microstructural softening in tests with dwell times for the low- but not for the high-strain regime. To rationalize the obtained fatigue data, the fracture-mechanics-based D_TMF concept, which was developed for TMF life assessment of ductile alloys, was applied. It is found that the D_TMF parameter correlates well with the measured fatigue lives, suggesting that subcritical growth of cracks (with sizes from a few microns to a few millimeters) governs failure in the investigated range of strain amplitudes.
KW - 9-12%Cr steel
KW - Thermomechanical fatigue
KW - Symmetric dwell periods
KW - Low strain
KW - Parametric modeling
PY - 2021
DO - https://doi.org/10.1016/j.msea.2020.140593
VL - 805
SP - 140593
PB - Elsevier B.V.
AN - OPUS4-52374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - An, Biwen Annie
A1 - Deland, Eric
A1 - Sobol, Oded
A1 - Yao, Jizheng
A1 - Skovhus, T. L.
A1 - Koerdt, Andrea
T1 - The differences in the corrosion product compositions of Methanogen-induced microbiologically influenced corrosion (Mi-MIC) between static and dynamic growth conditions
N2 - Currently, corrosion rates (CR) and/or corrosion products (CP) obtained for methanogen-induced microbiologically influenced corrosion (Mi-MIC) on carbon steel are mainly analyzed from static-incubations. By using a multiport-flow-column, much higher CRs (0.72 mm/yr) were observed, indicating static-incubations are not suitable for determining the corrosive potential of Mi-MIC. With the combination of various analytical methods (ToF-SIMS/SEM-EDS/SEM-FIB) and contrary to previously published data, we observed that CPs contained phosphorus, oxygen, magnesium, calcium and iron but lacked carbon-related species (e.g. siderite). Overall, siderite nucleation is disrupted by methanogens, as they convert aqueous bicarbonate into carbon dioxide for methanogenesis resulting in increased localized corrosion.
KW - Carbon steel
KW - Modelling studies
KW - SIMS
KW - SEM
KW - Reactor conditions
KW - Microbiologically influenced corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517632
DO - https://doi.org/10.1016/j.corsci.2020.109179
SN - 0010-938X
VL - 180
SP - 9179
PB - Elsevier
AN - OPUS4-51763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böllinghaus, Thomas
A1 - Wentland, Eva
A1 - Jaßmann, R.
A1 - Keller, R.
A1 - Wolfrum, Anne
T1 - Conservation of the Shaft #1 Headgear at the Tsumeb Mine, Namibia: Corrosion Protection
N2 - The Tsumeb Mine in Namibia represents one of the best-preserved mining sites in the world and is rapidly gaining cross-disciplinary interest among cultural and engineering scientists. Most of the open pit and the shaft mining equipment are still in place, including the ore processing units and the local power plant. The mining area thus deserves recognition as an industrial world heritage site, especially due to the rarity of such locations on the African continent. The Shaft #1 headgear, built in 1924, represents one of the oldest known riveted steel headgears of the Promnitz design worldwide. In contrast to similar steel structures located in the northern hemisphere, it has been exposed to a different rural semi-arid climate since it is located in the Otavi Mountain Land, characterized by semi-annual change of rainy and dry seasons. Parts of the Shaft #1 headgear have remained largely untouched for more than 70 years. Besides its outstanding heritage value, it thus also represents an interesting object for studying the composition of corrosion layers formed on mild steel surfaces when exposed to continental and industrial mining atmospheres. To find a suitable transparent corrosion prevention coating, various on-site coating samples were evaluated after 11 months of outdoor exposure, including Owatrol Oil®, which is based on natural oil and alkyd resin with strong wicking potential. The substance is frequently applied for the conservation of single components but is not yet widely used on large steel structures in the field of industrial heritage conservation. However, it represented the most stable anti-corrosion coating under the local atmospheric conditions in the on-site tests. Thus, the suitability of Owatrol Oil® as a transparent coating for corrosion protection of riveted mild steel structures in such climates was further investigated as a more recent approach for the conservation of large steel structures. Since the protective coatings are exposed to strong UV radiation in the local climate, the addition of a specific UV stabilizer mixture was also tested. For such laboratory tests, two mild steel samples were taken. The first one originated from a diagonal strut of the 1920s and the second one from a handrail mounted in the early 1960s. Using corresponding high-resolution scanning electron microscopy (HR-SEM) and energy-dispersive X-ray spectroscopy (EDX) it was found that the corrosion layers are predominantly composed of lepidocrocite and goethite. A weathering program simulating the specific environmental conditions at Tsumeb in a UV climate chamber was developed and the corrosion resistance of the mild steel surface was subsequently evaluated by potentiodynamic measurements. Such tests proved to be a fast and reliable procedure for ranking the corrosion resistance of the old mild steels. It was found that the long-term corrosion layers already provide significant protection against further corrosion in the simulated environment. However, the study also showed that this can be further improved by the application of the Owatrol Oil® as a protective coating that also seals crevices. The addition of the UV stabilizers, however, led to a significant deterioration in corrosion protection, even in comparison to that of the uncoated long-term corrosion layers on the surface. Regular overcoating seems more advisable for the long-term preservation of the Shaft #1 headgear than modifying the Owatrol Oil® Coating with the tested UV-stabilizing additives.
KW - Potentiodynamic measurements
KW - Mining head gear
KW - Mild steels
KW - Chemical composition
KW - Characterization of corrosion layers
KW - Alkyd resin-based coating
KW - UV-blocker addition
KW - Weathering tests
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541476
DO - https://doi.org/10.1080/00393630.2021.2004007
SN - 0039-3630
SP - 1
EP - 15
PB - Taylor & Francis Online
AN - OPUS4-54147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Röhsler, Andreas
A1 - Sobol, Oded
A1 - Hänninen, H.
A1 - Böllinghaus, Thomas
T1 - In-situ ToF-SIMS analyses of deuterium re-distribution in austenitic steel AISI 304L under mechanical load
N2 - Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (2H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α’-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress.
KW - ToF-SIMS
KW - Hydrogen
KW - Deuterium
KW - AISI 304L
KW - EBSD
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505142
DO - https://doi.org/10.1038/s41598-020-60370-2
VL - 10
IS - 1
SP - 3611
PB - Nature
AN - OPUS4-50514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Rhode, Michael
A1 - Yahyaoui, Hamza
A1 - Kannengießer, Thomas
ED - Lippold, J.
ED - Böllinghaus, Thomas
ED - Norrish, J.
ED - Scotti, A.
T1 - Hydrogen-assisted cracking in GMA welding of high-strength structural steels using the modified spray arc process
N2 - High-strength structural steels are used in machine, steel, and crane construction with yield strength up to 960 MPa. However, welding of these steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of microstructure, local stress/strain, and local hydrogen concentration. In addition to the three main factors, the used arc process is also important for the performance of the welded joint. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of high-strength steel grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been increasingly used for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared with the Conv. A. Economic benefits of using this arc type are a reduction of necessary weld beads and required filler material. In the present study, the susceptibility to HAC in the heat-affected zone (HAZ) of the high-strength structural steel S960QL was investigated with the externally loaded implant test. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. Both conducted test series showed same embrittlement index “EI” of 0.21 at diffusible hydrogen concentrations of 1.3 to 1.6 ml/100 g of arc weld metal. The fracture occurred in the HAZ or in the weld metal (WM). However, the test series withMod. SA showed a significant extension of the time to failure of several hours compared with tests carried out with Conv. A.
KW - High-strength steel
KW - GMA welding
KW - Diffusible hydrogen
KW - Implant test
KW - Fractography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515330
DO - https://doi.org/10.1007/s40194-020-00978-0
SN - 1878-6669
SN - 0043-2288
VL - 64
IS - 12
SP - 1997
EP - 2009
PB - Springer
CY - Berlin Heidelberg
AN - OPUS4-51533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steiner, S.
A1 - Heldt, J.
A1 - Sobol, Oded
A1 - Unger, Wolfgang
A1 - Frömeling, T.
T1 - Influence of oxygen vacancies on core-shell formation in solid solutions of (Na,Bi)TiO3 and SrTiO3
N2 - Solid solutions of (Na,Bi)TiO3 (NBT) and SrTiO3 (ST) are materials of interest for high-strain or high-energy density capacitor applications. Often, they exhibit chemical heterogeneity and develop core-shell structures during regular solid-state synthesis with an NBT-rich core. In this case, the NBT forms first so that the strontium needs to diffuse into the material to reach chemical homogeneity. Depending on the presence of core-shell structures, the electrical properties can vary drastically. In this work, we rationalize the effect of variations in oxygen vacancy concentration by Fe-acceptor and Nb-donor doping. It can be shown that a diffusion couple of strontium and oxygen is responsible for chemical homogenization and that the oxygen vacancy content can control the formation of a core-shell structure.
KW - Lead-free ceramics
KW - Bismuth titanates
KW - Core-shell structures
KW - Diffusion/diffusivity
KW - Ferroelectricity/ferroelectric materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525988
DO - https://doi.org/10.1111/jace.17845
SP - 1
EP - 10
PB - Wiley Periodicals LLC, John Wiley & Sons, Inc.
AN - OPUS4-52598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Sobol, Oded
A1 - Altmann, Korinna
A1 - Radnik, Jörg
A1 - Özcan Sandikcioglu, Özlem
T1 - Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part I: Effect on surface chemistry and corrosion behavior
N2 - Stainless steel AISI 304 surfaces were studied after a mild anodic polarization for oxide growth in the presence and absence of two derivatives of vitamin B2 (riboflavin and flavin mononucleotide) that can be secreted by metal‐reducing bacteria and act as a chelating agent for iron species. The alterations in oxide chemistry were studied by means of surface‐sensitive techniques such as X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry analysis. The complementary electrochemical characterization revealed a preferential growth of an oxide/hydroxide iron‐rich film that is responsible for an altered pit initiation and nucleation behavior. These findings suggest that as the corrosion behavior is determined by the interplay of the chemical and electronic properties, only a mild anodic polarization in the presence of redox‐active molecules is able to alter the chemical and electronic structure of the passive film formed on stainless steel AISI 304. This helps to achieve a profound understanding of the mechanisms of microbially influenced corrosion (MIC) and especially the possible effects of the redox‐active biomolecules, as they may play an important role in the corrosion susceptibility of stainless steel surfaces.
KW - Corrosion
KW - Stainless steel
KW - Surface analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528117
DO - https://doi.org/10.1002/maco.202012191
VL - 72
IS - 6
SP - 974
EP - 982
PB - Wiley
AN - OPUS4-52811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drexler, A.-K.
A1 - Konert, Florian
A1 - Nietzke, Jonathan
A1 - Hodžić, E.
A1 - Pastore, S.
A1 - Domitner, J.
A1 - Rhode, Michael
A1 - Sommitsch, C.
A1 - Böllinghaus, Thomas
T1 - Effect of Tensile Loading and Temperature on the Hydrogen Solubility of Steels at High Gas Pressure
N2 - The hydrogen solubility in ferritic and martensitic steels is affected by hydrostatic stress, pressure, and temperature. In general, compressive stresses decrease but tensile stresses increase the hydrogen solubility. This important aspect must be considered when qualifying materials for high‐pressure hydrogen applications (e.g., for pipelines or tanks) by using autoclave systems. In this work, a pressure equivalent for compensating the effect of compressive stresses on the hydrogen solubility inside of closed autoclaves is proposed to achieve solubilities that are equivalent to those in pipelines and tanks subjected to tensile stresses. Moreover, it is shown that the temperature effect becomes critical at low temperatures (e.g., under cryogenic conditions for storing liquid hydrogen). Trapping of hydrogen in the microstructure can increase the hydrogen solubility with decreasing temperature, having a solubility minimum at about room temperature. To demonstrate this effect, the generalized law of the hydrogen solubility is parameterized for different steels using measured contents of gaseous hydrogen. The constant parameter sets are verified and critically discussed with respect to the high‐pressure hydrogen experiments.
KW - Hydrogen
KW - Solubility
KW - Temperature
KW - Tensile loading
KW - Analytical calculation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586701
DO - https://doi.org/10.1002/srin.202300493
SN - 1611-3683
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-58670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böllinghaus, Thomas
A1 - Cross, Carl
T1 - Obituary: Prof. Dr.-Ing. Hans Hoffmeister
N2 - On November 3, 2023, our dear colleague, Prof. Dr.-Ing. Hans Hoffmeister, born in 1932 in Kassel, Germany, passed away in Ahrensburg, near Hamburg, Germany.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594160
DO - https://doi.org/10.1007/s40194-023-01675-4
SP - 1
EP - 2
PB - Springer Science and Business Media LLC
AN - OPUS4-59416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Research Data Management for Creep Reference Data of Ni Based Superalloys
N2 - In times of digital data processing and sharing, a central challenge for the Materials Science and Engineering (MSE) community is the complete digital representation of materials, including their relevant processing and microstructure details and the resulting properties. This digital representation, supported by digital infrastructures, enables entirely new qualities of collaborative work and is central to how we will conduct MSE research and develop products in the future. The main challenges are the composition, shaping, and description of the data so that it can be easily interpreted, trusted, and re-used. This presentation introduces our current effort to develop a best practice framework for generating and distributing creep reference datasets for Ni-based superalloys, which builds on previous approaches. Researchers can use such datasets to compare their own experimental or simulation results, used, for instance, to perform simulation-based alloy design and optimization or in the verification of the own testing equipment. The concept includes building an easily accessible digital infrastructure to annotate and discover the datasets and the integration of an ontology that aligns with the necessary metadata schema. With the help of an ontology, the reference dataset for creep can be semantically described, thus enabling the digital representation and reusage of shared concepts from domain experts and the community. To achieve this, it is necessary to establish a defined vocabulary with corresponding relations and annotations. The interplay between a digital infrastructure, the agreement on the necessary metadata and related metadata schema, and an underlying ontology will ensure that data and results can be easily shared, taken up, and re-used, thus fulfilling the FAIR principles (Findable, Accessible, Interoperable, Reusable). Furthermore, we aim to develop a widely accepted definition of reference data and data quality levels and to reach a self-supported community process. We intend to motivate the discussion about reference material datasets, necessary metadata, and future collaborations within the creep community.
T2 - 16th International Conference on Creep and Fracture of Engineering Materials and Structures
CY - Bangalore, India
DA - 28.07.2024
KW - Reference Data
KW - Creep
KW - Data schema
KW - Research Data Management
PY - 2024
AN - OPUS4-60837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Low-cycle-fatigue behavior of stainless steel 316L manufactured by laser powder bed fusion
N2 - This contribution presents the results of an experimental study on the LCF behavior of an austenitic 316L stainless steel produced by laser powder bed fusion featuring a low defect population, which allows for an improved understanding of the role of other typical aspects of a PBF‑LB microstructure. The LCF tests were performed between room temperature and 600 °C. A hot‑rolled 316L variant was tested as a reference. The mechanical response is characterized by strain-life curves, a Coffin‑Manson‑Basquin fitting, and cyclic deformation curves. The damage and deformation mechanisms are studied with X-ray computed tomography, optical and electron microscopy. The PBF‑LB/M/316L exhibits lower fatigue lives at lower strain amplitudes. The crack propagation is mainly transgranular. The solidification cellular structure seems to be the most relevant underlying microstructural feature determining the cyclic deformation behavior.
T2 - TMS 2024 Annual Meeting & Exhibition
CY - Orlando, Florida, US
DA - 03.03.2024
KW - AGIL
KW - Additive Fertigung
KW - Mikrostruktur
KW - LCF
KW - 316L
PY - 2024
AN - OPUS4-59782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaudhuri, Somsubhro
T1 - Infrarot-Thermografie zur Überwachung von mittels Kaltgasspritzen (Cold- Spray) reparierten Bauteilen unter zyklischer Belastung
N2 - Das Kaltgasspritzen ist ein vielversprechendes Verfahren für die Reparatur von metallischen Komponenten , insbesondere sicherheitsrelevante Bauteile in der Luft- und Raumfahrt. Durch die Abscheidung von Partikeln mit hoher Geschwindigkeit ohne Schmelzen entsteht eine mechanisch verbundene Grenzfläche zwischen dem Substrat und der Beschichtung. Die Überwachung der Integrität dieser Grenzfläche unter Ermüdungsbelastung stellt jedoch nach wie vor eine Herausforderung dar, da die Grenzfläche nicht sichtbar ist.
Die Röntgencomputertomographie (XCT) wird bereits häufig zur Charakterisierung von Defekten in Kaltgasspritzbeschichtungen und Grenzflächenbereichen eingesetzt. XCT bietet zwar hochauflösende Einblicke in interne Strukturen, ihre Anwendung bei mechanischen Prüfungen ist jedoch aufgrund praktischer Einschränkungen bei der In-situ-Implementierung begrenzt.
In dieser Studie wurde die Infrarot-Thermografie (IRT) eingesetzt, um die Schadensentwicklung in kaltgespritzten Al6061-Proben während Zug- und Ermüdungsbelastung zu überwachen. Eine gekühlte Infrarotkamera mit hoher Bildfrequenz wurde synchron mit den mechanischen Prüfungen eingesetzt, und die Daten wurden mit Lock-in-Thermografieverfahren verarbeitet, um Phasen- und Amplitudensignale zu extrahieren, die mit thermoelastischen und dissipativen Effekten in Zusammenhang stehen.
Die IRT ermöglichte die Erkennung thermischer Anomalien an der Grenzfläche zwischen Beschichtung und Substrat, die mit der Rissbildung und -ausbreitung korrelierten. Parallel dazu wurde die digitale Bildkorrelation (DIC) angewendet, um Oberflächenverformungsfelder abzubilden. Der Vergleich von DIC und IRT ermöglichte eine multimodale Betrachtung der Schadensmechanismen. Die fraktografische Analyse bestätigte, dass die mit IRT identifizierten Bereiche gut mit der Rissentstehung an der Grenzfläche übereinstimmen.
Diese Ergebnisse bestätigen den Wert der Infrarot-Thermografie als zerstörungsfreies Verfahren zur In-situ-Überwachung der strukturellen Integrität bei Kaltgasspritzreparaturen. Sie ergänzt XCT und DIC, indem sie eine kontinuierliche Verfolgung der Schadensentwicklung unter realistischen Belastungsbedingungen ermöglicht.
T2 - Thermo25: Infrarot-Thermografie im Dialog zwischen Forschung und Praxis
CY - Garching bei München, Germany
DA - 12.11.2025
KW - Thermografie
KW - Lock-In
KW - Kaltgasspritzen
KW - Grenzflächenintegrität
PY - 2025
AN - OPUS4-64709
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
A1 - Fabry, Çağtay
A1 - Rethmeier, Michael
A1 - Ratkovac, Mirjana
A1 - Thiele, Marc
A1 - Baeßler, Matthias
T1 - Innovative Design- und Fertigungsstrategien zur Steigerung der Leichtbaupotenziale im Stahlbau
N2 - Ziel des Verbundvorhabens „SmartWeld“ ist es, für die schweißtechnische Fertigung von Stahlbaustrukturen exemplarisch am Beispiel von Hohlprofilknoten, welche als designrelevante Elemente von Gründungsstrukturen für Offshore-Windenergieanlagen (OWEA) einsetzbar sind, die Möglichkeiten des Leichtbaus unter konsequenter Digitalisierung der Fertigungskette aufzuzeigen, um einerseits die Ressourceneffizienz zu forcieren und gleichzeitig wettbewerbsfähige Fertigungsstrategien aufzuzeigen.
Innerhalb von „SmartWeld“ werden daher die Möglichkeiten einer wirtschaftlichen Fertigung von Leichtbau-Gründungsstrukturen am Beispiel aufgelöster Tragstrukturen (Jackets) aufgezeigt. Eine lastgerechte Auslegung der Schweißverbindungen nach bionischen Prinzipien ermöglicht, weitere Einsparpotenziale an Ressourcen bei gleichzeitiger Erhöhung der Lebensdauer zu erschließen.
Die Ausnutzung konstruktiver Prinzipien des Leichtbaus zur Erzeugung innovativer und ressourcenschonender Produkte erfordert den Einsatz digitaler Werkzeuge in der Designphase, der virtuellen Absicherung, der Fertigung und Qualitätsüberwachung sowie nachgelagerten Bauteilprüfung zur Abbildung der Nutzungsphase. Im Rahmen der Arbeiten wird daher der gesamte Produktentstehungs- und Prüfprozess betrachtet. Dies beinhaltet das Design im Kontext des konstruktiven Leichtbaus, den schweißtechnischen Fertigungsprozess, die Bauteilprüfung sowie den Transfer der Ergebnisse in die Industrie durch serientaugliche Demonstratoren. Der Fokus der Arbeiten ist, die Fertigung auch im Umfeld eines für großskalige Stahlstrukturen üblichen hohen Individualisierungsgrades schweißtechnisch zu automatisieren und das Leichtbaupotenzial gezielt umzusetzen. Die Vorgaben aus der Designphase hinsichtlich einer lastgerechten Gestaltung bzw. Implementierung bionischer Ansätze können so gezielt durch einen adaptiven, automatisierten Schweißprozess eingestellt werden. Dies führt zu einer Erhöhung der Ermüdungs¬festigkeit und damit Produktlebensdauer, wodurch die Strukturen dünnwandiger ausgeführt und Ressourcen sowie CO2 eingespart werden können.
T2 - Sitzung des DVS Fachausschuss FA03 - Lichtbogenschweißen
CY - Rostock, Germany
DA - 11.10.2022
KW - Offshore Windenergieanlagen
KW - Gründungsstrukturen
KW - Leichtbau
KW - Automatisierte schweißtechnische Fertigung
PY - 2022
AN - OPUS4-56656
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Automated arc welding of support structures for offshore wind turbines
N2 - Offshore wind energy plays an important role for the desired transition towards a carbon dioxide free industry within the next decades. However, the grounding of the offshore wind plants governs the overall installation process besides bureaucratic bottlenecks.
The application of lightweight principles in steel construction, e.g. the usage dissolved load-bearing structures, so called Jackets foundations, offer great potential in reducing the resource consumption, especially with respect to the needed amount of steel.
In this context this paper focuses on a fully digitalization of the welding manufacturing and as well as testing chain to enable a fully automated manufacturing as well as quality assessment of tubular nodes as key element of Jackets foundation structures. Furthermore, the relationship between the seam shape geometry and resulting fatigue strength is evaluated by numerical methods incorporating bionic principles. It is shown that tubular nodes can be welded fully automatically taking geometry tolerances into account. Moreover, the seam shape could be manufactured as requested by the numerical models which offers great potential for an extended lifetime. Subsequently, the improvements in resource efficiency and reduction of carbon dioxide emissions are evaluated by a life-cycle-assessment.
T2 - IIW Annual Assembly 2022 Tokyo, Japan
CY - Tokyo, Japan
DA - 21.07.2022
KW - Offshore wind turbines
KW - Support structures
KW - Automated welding
KW - Lightweight principles
PY - 2022
AN - OPUS4-56653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Fabry, Çağtay
A1 - Hirthammer, Volker
A1 - Scherer, Martin K.
T1 - weldx - welding data exchange format
N2 - Scientific welding data covers a wide range of physical domains and timescales and are measured using various different sensors. Complex and highly specialized experimental setups at different welding institutes complicate the exchange of welding research data further. The WelDX research project aims to foster the exchange of scientific data inside the welding community by developing and establishing a new open source file format suitable for the documentation of experimental welding data and upholding associated quality standards. In addition to fostering scientific collaboration inside the national and international welding community an associated advisory committee will be established to oversee the future development of the file format. The proposed file format will be developed with regard to current needs of the community regarding interoperability, data quality and performance and will be published under an appropriate open source license. By using the file format objectivity, comparability and reproducibility across different experimental setups can be improved.
KW - Welding
KW - Research data management
KW - Open science
KW - Open Data
KW - WelDX
PY - 2021
DO - https://doi.org/10.5281/zenodo.6563282
PB - Zenodo
CY - Geneva
AN - OPUS4-55226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
T1 - Welding of thick metal plates with laser - Where are the limits?
N2 - -With modern high-power lasers (and vacuum) penetration around 100 mm is possible
-Important for industrial applications: single-pass full penetration welds with tolerances
-Contactless EM-backing helps to overcome many main restrictions:
-Single-pass HLAW of up to 30 mm can be realized with 20 kW laser power
-Increase of the gap bridgeability and misalignement of edges
-Lower sensitivity to manufacturing tolerances and edge quality; samples can be prepared by a plasma-cut instead of time-consuming milling process
-Gives the possibility to increase the welding parameter window and cooling rate so that the required mechanical properties can be reached
-Improved filler wire mixing behaviour
T2 - AKL22 - International Laser Technology Congress
CY - Aachen, Germany
DA - 04.05.2022
KW - Laser hybrid welding
KW - Thick-walled steel
KW - High-power laser
KW - Electromagnetic backing
PY - 2022
AN - OPUS4-56367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Waitelonis, Jörg
A1 - Birkholz, Henk
A1 - Jung, Matthias
A1 - Schilling, Markus
A1 - v. Hartrott, Philipp
A1 - Bruns, Marian
A1 - Schaarschmidt, Jörg
A1 - Beilke, Kristian
A1 - Mutz, Marcel
A1 - Nebel, Vincent
A1 - Königer, Veit
A1 - Beran, Lisa
A1 - Kraus, Tobias
A1 - Vyas, Akhilesh
A1 - Vogt, Lars
A1 - Blum, Moritz
A1 - Ell, Basil
A1 - Chen, Ya‐Fan
A1 - Waurischk, Tina
A1 - Thomas, Akhil
A1 - Durmaz, Ali Riza
A1 - Ben Hassine, Sahar
A1 - Fresemann, Carina
A1 - Dziwis, Gordian
A1 - Beygi Nasrabadi, Hossein
A1 - Hanke, Thomas
A1 - Telong, Melissa
A1 - Pirskawetz, Stephan
A1 - Kamal, Mohamed
A1 - Bjarsch, Thomas
A1 - Pähler, Ursula
A1 - Hofmann, Peter
A1 - Leemhuis, Mena
A1 - Özçep, Özgür L.
A1 - Meyer, Lars‐Peter
A1 - Skrotzki, Birgit
A1 - Neugebauer, Jörg
A1 - Wenzel, Wolfgang
A1 - Sack, Harald
A1 - Eberl, Chris
A1 - Portella, Pedro Dolabella
A1 - Hickel, Tilmann
A1 - Mädler, Lutz
A1 - Gumbsch, Peter
T1 - Concepts for a Semantically Accessible Materials Data Space: Overview over Specific Implementations in Materials Science
N2 - This article describes advancements in the ongoing digital transformation in materials science and engineering. It is driven by domain‐specific successes and the development of specialized digital data spaces. There is an evident and increasing need for standardization across various subdomains to support science data exchange across entities. The MaterialDigital Initiative, funded by the German Federal Ministry of Education and Research, takes on a key role in this context, fostering collaborative efforts to establish a unified materials data space. The implementation of digital workflows and Semantic Web technologies, such as ontologies and knowledge graphs, facilitates the semantic integration of heterogeneous data and tools at multiple scales. Central to this effort is the prototyping of a knowledge graph that employs application ontologies tailored to specific data domains, thereby enhancing semantic interoperability. The collaborative approach of the Initiative's community provides significant support infrastructure for understanding and implementing standardized data structures, enhancing the efficiency of data‐driven processes in materials development and discovery. Insights and methodologies developed via the MaterialDigital Initiative emphasize the transformative potential of ontology‐based approaches in materials science, paving the way toward simplified integration into a unified, consolidated data space of high value.
KW - Semantic Interoperability
KW - Data Spaces
KW - Integration Workflows
KW - MaterialDigital
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622952
DO - https://doi.org/10.1002/adem.202401092
SN - 1527-2648
SP - 1
EP - 25
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-62295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rehmer, Birgit
A1 - Bayram, Faruk
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
T1 - Elastic modulus data for additively and conventionally manufactured variants of Ti-6Al-4V, IN718 and AISI 316 L
N2 - This article reports temperature-dependent elastic properties (Young’s modulus, shear modulus) of three alloys measured by the dynamic resonance method. The alloys Ti-6Al-4V, Inconel IN718, and AISI 316 L were each investigated in a variant produced by an additive manufacturing processing route and by a conventional manufacturing processing route. The datasets include information on processing routes and parameters, heat treatments, grain size, specimen dimensions, and weight, as well as Young’s and shear modulus along with their measurement uncertainty. The process routes and methods are described in detail. The datasets were generated in an accredited testing lab, audited as BAM reference data, and are hosted in the open data repository Zenodo. Possible data usages include the verification of the correctness of the test setup via Young’s modulus comparison in low-cycle fatigue (LCF) or thermo-mechanical fatigue (TMF) testing campaigns, the design auf VHCF specimens and the use as input data for simulation purposes.
KW - Elastic modulus
KW - Young's modulus
KW - Shear modulus
KW - Additive manufacturing
KW - AISI 316L
KW - IN 718
KW - Ti-6Al-4V
KW - Reference data
KW - Temperature dependence
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579716
DO - https://doi.org/10.1038/s41597-023-02387-6
VL - 10
IS - 1
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-57971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lin, Y.-Y.
A1 - Schleifer, F.
A1 - Holzinger, M.
A1 - Ta, N.
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
A1 - Glatzel, U.
A1 - Fleck, M.
T1 - Quantitative Shape-Classification of Misfitting Precipitates during Cubic to Tetragonal Transformations: Phase-Field Simulations and Experiments
N2 - The effectiveness of the mechanism of precipitation strengthening in metallic alloys depends on the shapes of the precipitates. Two different material systems are considered: tetragonal γ′′ precipitates in Ni-based alloys and tetragonal θ′ precipitates in Al-Cu-alloys. The shape formation and evolution of the tetragonally misfitting precipitates was investigated by means of experiments and phase-field simulations. We employed the method of invariant moments for the consistent shape quantification of precipitates obtained from the simulation as well as those obtained from the experiment. Two well-defined shape-quantities are proposed: (i) a generalized measure for the particles aspect ratio and (ii) the normalized λ2, as a measure for shape deviations from an ideal ellipse of the given aspect ratio. Considering the size dependence of the aspect ratio of γ′′ precipitates, we find good agreement between the simulation results and the experiment. Further, the precipitates’ in-plane shape is defined as the central 2D cut through the 3D particle in a plane normal to the tetragonal c-axes of the precipitate. The experimentally observed in-plane shapes of γ′′-precipitates can be quantitatively reproduced by the phase-field model.
KW - γ″ phase
KW - Phase-field simulation
KW - Misfitting precipitate
KW - Nickel-base alloy
KW - Al-Cu alloy
KW - θ′ phase
KW - Precipitate shape
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522743
DO - https://doi.org/10.3390/ma14061373
VL - 14
IS - 6
SP - 1373
PB - MDPI
AN - OPUS4-52274
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charmi, Amir
A1 - Falkenberg, Rainer
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Sommer, Konstantin
A1 - Ulbricht, Alexander
A1 - Sprengel, Maximilian
A1 - Saliwan Neumann, Romeo
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Mechanical anisotropy of additively manufactured stainless steel 316L: An experimental and numerical study
N2 - The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures. To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF). Tensile specimens were machined from these AM bulk materials for three different inclinations: 0◦, 45◦, and 90◦ relative to the build plate. Dynamic Young’s modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography (μCT), and texture analysis with electron backscatter diffraction (EBSD). These investigations revealed that the specimens exhibited near full density and the detected defects were spherical. Furthermore, the residual stresses in the loading direction were between −74 ± 24 MPa and 137 ± 20 MPa, and the EBSD measurements showed a preferential ⟨110⟩ orientation parallel to the build direction. A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture.
KW - Mechanical anisotropy
KW - Residual stress
KW - Crystal plasticity
KW - Selective laser melting (SLM)
KW - Laser beam melting (LBM)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511719
DO - https://doi.org/10.1016/j.msea.2020.140154
SN - 0921-5093
VL - 799
SP - 140154
PB - Elsevier B.V.
AN - OPUS4-51171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ta, N.
A1 - Bilal, M. U.
A1 - Häusler, I.
A1 - Saxena, A.
A1 - Lin, Y.-Y.
A1 - Schleifer, F.
A1 - Fleck, M.
A1 - Glatzel, U.
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
T1 - Simulation of the θ′ Precipitation Process with Interfacial Anisotropy Effects in Al-Cu Alloys
N2 - The effects of anisotropic interfacial properties and heterogeneous elasticity on the growth and ripening of plate-like θ′-phase (Al2Cu) in Al-1.69 at.% Cu alloy are studied. Multi-phase-field simulations are conducted and discussed in comparison with aging experiments. The precipitate/matrix interface is considered to be anisotropic in terms of its energy and mobility. We find that the additional incorporation of an anisotropic interfacial mobility in conjunction with the elastic anisotropy result in substantially larger aspect ratios of the precipitates closer to the experimental observations. The anisotropy of the interfacial energy shows comparably small effect on the precipitate’s aspect ratio but changes the interface’s shape at the rim. The effect of the chemo-mechanical coupling, i.e., the composition dependence of the elastic constants, is studied as well. We show that the inverse ripening phenomenon, recently evidenced for δ’ precipitates in Al-Li alloys (Park et al. Sci. Rep. 2019, 9, 3981), does not establish for the θ′ precipitates. This is because of the anisotropic stress fields built around the θ′ precipitates, stemming from the precipitate’s shape and the interaction among different variants of the θ′ precipitate, that disturb the chemo-mechanical effects. These results show that the chemo-mechanical effects on the precipitation ripening strongly depend on the degree of sphericity and elastic isotropy of the precipitate and matrix phases.
KW - Aging
KW - Phase-field simulation
KW - Interfacial anisotropy
KW - Chemo-mechanical coupling
KW - Precipitation
KW - Elasticity
KW - θ′-(Al2Cu) precipitate phase
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522672
DO - https://doi.org/10.3390/ma14051280
VL - 14
IS - 5
SP - 1280
PB - MDPI
AN - OPUS4-52267
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goedecke, Caroline
A1 - Dittmann, Daniel
A1 - Eisentraut, Paul
A1 - Wiesner, Yosri
A1 - Schartel, Bernhard
A1 - Klack, Patrick
A1 - Braun, Ulrike
T1 - Evaluation of thermoanalytical methods equipped with evolved gas analysis for the detection of microplastic in environmental samples
N2 - Microplastic particles are currently detected in almost all environmental compartments. The results of detection vary widely, as a multitude of very different methods are used with very different requirements for analytical validity.
In this work four thermoanalytical methods are compared and their advantages and limitations are discussed. One of them is thermal extraction-desorption gas chromatography mass spectrometry (TED-GC/MS), an analysis method for microplastic detection that has become established in recent years. In addition, thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS) were applied, two methods that are less common in this field but are still used in other research areas. Finally, microscale combustion calorimeter (MCC) was applied, a method not yet used for microplastic detection.
The presented results are taken from a recently published interlaboratory comparison test by Becker et al. (2020). Here a reference material consisting of suspended matter and specified added polymer masses was examined, and only the results of the recoveries were presented. In the present paper, however, the results for the individual polymers are discussed in detail and individual perspectives for all instruments are shown.
It was found that TED-GC/MS is the most suitable method for samples with unknown matrix and unknown, variable kinds and contents of microplastic. TGA-FTIR is a robust method for samples with known matrix and with defined kinds of microplastic. TGA-MS may offer a solution for the detection of PVC particles in the future. MCC can be used as a very fast and simple screening method for the identification of a potential microplastic load of standard polymers in unknown samples.
KW - Microplastic
KW - TED-GC/MS
KW - TGA-MS
KW - TGA-FTIR
KW - MCC
KW - Thermal analysis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516687
DO - https://doi.org/10.1016/j.jaap.2020.104961
VL - 152
SP - 104961
PB - Elsevier B.V.
AN - OPUS4-51668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markwart, J. C.
A1 - Battig, Alexander
A1 - Urbaniak, T.
A1 - Haag, K.
A1 - Koschek, K.
A1 - Schartel, Bernhard
A1 - Wurm, F. R.
T1 - Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials
N2 - Recycling of crosslinked fiber-reinforced polymers is difficult. Moreover, as they are often based on flammable resins, additional additives are needed. So-called “vitrimers” open the possibility of Recycling and reprocessing and repairing with dynamically crosslinked chemistries. To date, vitrimer-based composites still need flame retardant additives, such as organophosphates. An additive-free vitrimer composite has not been reported. Herein, we synthesized an intrinsic flame-retardant vitrimer, relying on vinylogous polyurethanes containing covalently installed phosphonates as flame-retardant units and prepared glassfiber-reinforced composites. We studied recycling and flame retardant properties and compared the data to phosphorus-free vitrimers and conventional epoxy resins (with and without additive flame retardant).
Our phosphonate-based vitrimer proved in first tests, a flame retardant effect comparable to commercial flame retardant resins. The bending strength and bending modulus for the phosphorus-vitrimer glass fiber composites were comparable to glass fiber composites with permanently cross-linked epoxies. In summary, we were able to prove that the covalent installation of phosphonates into vitrimers allows the preparation of recyclable and intrinsic flame retardant composites that do not need flame retardant additives. We believe this concept can be expanded to other polymer networks and additives to generate recyclable and sustainable high-performance materials.
KW - Vitrimer
KW - Flame retardant
KW - Recyclable
KW - Organophosphonate
KW - Polyurethane
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510889
DO - https://doi.org/10.1039/d0py00275e
VL - 11
IS - 30
SP - 4933
EP - 4941
AN - OPUS4-51088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rockenhäuser, Christian
A1 - Rowolt, C.
A1 - Milkereit, B.
A1 - Darvishi Kamachali, Reza
A1 - Kessler, O.
A1 - Skrotzki, Birgit
T1 - On the long-term aging of S-phase in aluminum alloy 2618A
N2 - The aluminum alloy 2618A is applied for engine components such as radial compressor wheels which operate for long time at elevated temperatures. This results in coarsening of the hardening precipitates and degradation in mechanical properties during the long-term operation, which is not taken into account in the current lifetime prediction models due to the lack of quantitative microstructural and mechanical data. To address this issue, a quantitative investigation on the evolution of precipitates during long-term aging at 190 °C for up to 25,000 h was conducted. Detailed transmission electron microscopy (TEM) was combined with Brinell hardness measurements and thorough differential scanning calorimetry (DSC) experiments. The results showthat GPB zones and S-phase Al2CuMg grow up to < 1,000 h during which the GPB zones dissolve and S-phase precipitates form. For longer aging times, only S-phase precipitates coarsen, which can be well described using the Lifshitz–Slyozov Wagner theory of ripening. A thorough understanding of the underlying microstructural processes is a prerequisite to enable the integration of aging behavior into the established lifetime models for components manufactured from alloy 2618A.
KW - Long-term aging
KW - Transmission electron microscopy (TEM)
KW - Differential scanning calorimetry (DSC)
KW - Microstructure
KW - S-phase
KW - Ostwald ripening
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519899
DO - https://doi.org/10.1007/s10853-020-05740-x
SN - 0022-2461
VL - 56
IS - 14
SP - 8704
EP - 8716
PB - Springer Nature
AN - OPUS4-51989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
T1 - Rissfortschrittsuntersuchungen an gefügten Nickelbasiswerkstoffen bei hoher Temperatur
N2 - Nickelbasierte Superlegierungen werden in großem Umfang für Gasturbinenschaufeln verwendet, da sie einer Kombination aus hoher Belastung und hohen Temperaturen widerstehen können. Um die Effizienz moderner Gasturbinen zu verbessern, werden hohe Betriebstemperaturen angestrebt. Diese hohen Temperaturen verbunden mit mechanischen Belastungen führen zu Materialschäden aufgrund von Kriechen, Ermüdung und anderen Schadensmechanismen. Aus diesem Grund werden Turbinenschaufeln regelmäßig im Rahmen von Wartungs- und Instandsetzungsmaßnahmen geprüft und falls erforderlich ausgetauscht, um ein katastrophales Versagen im Betrieb zu vermeiden. Ein kompletter Austausch ist mit sehr hohen Kosten verbunden, weshalb geeignete Reparaturverfahren entwickelt wurden und werden. Neue Reparaturtechnologien wie die Additive Fertigung, Lötverfahren und der Einsatz von vorgesinterten Vorformen (Presintered Preform PSP) sollen eine effiziente Reparatur und optimale Eigenschaften der reparierten Bauteile sichterstellen.
Im Allgemeinen stellen die Fügezonen typische Schwachstellen dar, da sie die Anrissbildung und Rissausbreitung erleichtern und die Anzahl der Lastzyklen bis zum Bruch reduzieren können. Aus diesem Grund ist eine umfassende Untersuchung des Rissfortschrittsverhaltens in diesen, durch neue Reparaturtechnologien entstandenen Bereichen erforderlich, um die Restlebensdauer der Turbinenschaufeln vorherzusagen.
Als ein erster Beitrag zu dieser Fragestellung werden Ergebnisse von Rissfortschrittsversuchen (Fig. 1) an SENT-Proben vorgestellt, die durch Engspaltlöten gefügt wurden. Die Versuche wurden bei einer Temperatur von 950 °C und einem Spannungsverhältnis R = 0,1 durchgeführt. Die Erfassung des Rissfortschritts erfolgte mit dem Gleichstrom-Potentialsonden-Verfahren. Mit der Finite-Element-Methode konnte der Spannungsintensitätsfaktor für gefügte SENT-Proben berechnet werden, der dann zur Berechnung der Risswachstumskurven verwendet wurde. Eine abschließende licht- und rasterelektronenmikroskopische Untersuchung der Bruchflächen soll einen Beitrag zum Verständnis der Bruchmechanismen liefern und klären, ob der Riss sich im Lotwerkstoff, im Grundwerkstoff oder in der Grenzfläche ausbreitet. Die Ergebnisse werden zur Kalibrierung des Rissfortschrittsmodells und der Auslegung zukünftiger Komponenten verwendet.
T2 - Werkstoffprüfung Tagung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Rissfortschritts
KW - Gelötete Nickel-Basis-Legierungen
PY - 2022
AN - OPUS4-60894
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Evans, Alexander
T1 - Ageing behaviour of laser powder bed fused 316L: a powder to failure approach
N2 - Laser powder bed fusion (LPBF) is an additive manufacturing process for materials which inherently tends to yield various degrees of metastable hierarchical microstructures, defects and high residual stresses in the as-built condition depending on the process parameters. The understanding of the evolution of these typical features during heat treatment and subsequent thermal and mechanical ageing is crucial for the wider acceptance for safety critical structures. A multi-disciplinary research project at BAM studying the development of the microstructure, defects, residual stresses typical of LPBF 316L and their evolution during thermal and mechanical ageing has led to insights into the stability of these inherent features. This presentation aims to give a broad overview of the project with a few specific cases of investigation. Firstly, the formation of residual stresses, the nature of the initial microstructure, the tensile properties and a modelling approach to understand the anisotropy will be presented. This will be followed by examples of studies of their evolution during heat treatment, long term thermal exposure, and room temperature and high temperature mechanical testing compared to a baseline of conventional wrought variant of the same alloy.
T2 - International Conference on Additive Manufacturing 2021 (ICAM 2021)
CY - Online meeting
DA - 01.11.2021
KW - Ageing
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - AGIL
PY - 2021
AN - OPUS4-54106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Winterkorn, René
A1 - Fabry, Çağtay
A1 - Rethmeier, Michael
A1 - Ratkovac, Mirjana
A1 - Thiele, Marc
A1 - Baeßler, Matthias
T1 - Innovative Design- und Fertigungsstrategien zur Steigerung der Leichtbaupotenziale im Stahlbau
N2 - Ziel des Verbundvorhabens „SmartWeld“ ist es, für die schweißtechnische Fertigung von Stahlbaustrukturen exemplarisch am Beispiel von Hohlprofilknoten, welche als designrelevante Elemente von Gründungsstrukturen für Offshore-Windenergieanlagen (OWEA) einsetzbar sind, die Möglichkeiten des Leichtbaus unter konsequenter Digitalisierung der Fertigungskette aufzuzeigen, um einerseits die Ressourceneffizienz zu forcieren und gleichzeitig wettbewerbsfähige Fertigungsstrategien aufzuzeigen.
Innerhalb von „SmartWeld“ werden daher die Möglichkeiten einer wirtschaftlichen Fertigung von Leichtbau-Gründungsstrukturen am Beispiel aufgelöster Tragstrukturen (Jackets) aufgezeigt. Eine lastgerechte Auslegung der Schweißverbindungen nach bionischen Prinzipien ermöglicht, weitere Einsparpotenziale an Ressourcen bei gleichzeitiger Erhöhung der Lebensdauer zu erschließen.
Die Ausnutzung konstruktiver Prinzipien des Leichtbaus zur Erzeugung innovativer und ressourcenschonender Produkte erfordert den Einsatz digitaler Werkzeuge in der Designphase, der virtuellen Absicherung, der Fertigung und Qualitätsüberwachung sowie nachgelagerten Bauteilprüfung zur Abbildung der Nutzungsphase. Im Rahmen der Arbeiten wird daher der gesamte Produktentstehungs- und Prüfprozess betrachtet. Dies beinhaltet das Design im Kontext des konstruktiven Leichtbaus, den schweißtechnischen Fertigungsprozess, die Bauteilprüfung sowie den Transfer der Ergebnisse in die Industrie durch serientaugliche Demonstratoren. Der Fokus der Arbeiten ist, die Fertigung auch im Umfeld eines für großskalige Stahlstrukturen üblichen hohen Individualisierungsgrades schweißtechnisch zu automatisieren und das Leichtbaupotenzial gezielt umzusetzen. Die Vorgaben aus der Designphase hinsichtlich einer lastgerechten Gestaltung bzw. Implementierung bionischer Ansätze können so gezielt durch einen adaptiven, automatisierten Schweißprozess eingestellt werden. Dies führt zu einer Erhöhung der Ermüdungs¬festigkeit und damit Produktlebensdauer, wodurch die Strukturen dünnwandiger ausgeführt und Ressourcen sowie CO2 eingespart werden können.
T2 - 9. Forum Leichtbau - Fortschrittliche Fertigungstechnologien und Werkstoffe für den Klimaschutz
CY - Berlin, Germany
DA - 29.09.2022
KW - Offshore Windenergieanlagen
KW - Gründungsstrukturen
KW - Leichtbau
KW - Bionik
KW - Automatisierte schweißtechniche Fertigung
PY - 2022
AN - OPUS4-56655
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - Management of Reference Data of Creep of Ni Based Superalloys Exemplified for CMSX 6
N2 - Research data management (RDM) framework to conceptualize & implement a digital infrastructure for the Generation, Distribution, and Utilization of reference datasets of materials. Documentation of the test data is often incomplete. This concerns, e.g., material’s manufacturing process or chemical composition, or test equipment’s description and its calibration status. Our concept addresses this issue by proposing the implementation of a requirements profile. A crucial part of the concept is to reach a community-agreement on the definition of reference data and on the underlying data schema and vocabulary.
T2 - 2. SupERBO Symposium on Superalloys
CY - Bochum, Germany
DA - 27.02.2025
KW - NFDI MatWerk
KW - Referenzdaten
KW - Kriechen
PY - 2025
AN - OPUS4-64859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - In-situ Monitoring der Additiven Fertigung von Metallen im LPA Prozess mittels Optischer Emissionsspektrometrie (OES) und Thermografie (TT)
N2 - Einer der aussichtsreichsten Ansätze, die Qualität und Sicherheit der gefertigten Teile in der metallbasierten additiven Fertigung (AM) zu erhöhen und die Notwendigkeit aufwändiger und zeitintensiver, zerstörender oder zerstörungsfreier Prüfungen (ZfP) nach der Fertigung zu verringern, liegt in dem Einsatz von in-situ Prozessüberwachungstechniken. Viele wichtige Prozessgrößen bei der additiven Fertigung sind thermischer Natur, wie z.B. die Temperatur des Schmelzbades. Aufgrund der Zugänglichkeit zum Werkstück während des Bauprozesses bieten sich optische Verfahren zur Temperaturbestimmung an. Für die Thermografie und Optische Emissionsspektrometrie im IR-Bereich, welche für die in-situ Anwendung prinzipiell als geeignet angesehen werden können, gibt es allerdings noch wenig konkrete praktische Umsetzungen, da die Möglichkeiten und individuellen Grenzen dieser Methoden, angewendet auf AM, noch nicht ausreichend erforscht sind. Aus diesem Grund verfolgt die BAM mit dem Projekt „Process Monitoring of AM“ (ProMoAM) im Themenfeld Material das Ziel, Verfahren des Prozessmonitorings zur in-situ Bewertung der Qualität additiv gefertigter Metallbauteile weiterzuentwickeln.
Im Beitrag wird der Fokus auf eine Versuchsserie gelegt, bei der Aufbau von Probekörpern aus dem austenitischen Edelstahl 316L mittels Laser-Pulver-Auftragschweißen (LPA) durch od. mit Hilfe von IR-Spektrometrie und Thermografie in-situ überwacht wurde. Hierbei stellen u.a. die hohe Bandbreite der zu messenden Temperaturen, die Bestimmung der Emissivität und ihre Änderung bei Phasenübergängen des Metalls große experimentelle Herausforderungen dar, wobei jede Methode individuelle Vor- und Nachteile aufweist, welche verglichen werden.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Additive Manufacturing
KW - Thermography
KW - Direct Energy Deposition
KW - Additive Fertigung
KW - Thermografie
KW - Laserauftragschweißen
PY - 2021
AN - OPUS4-52744
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
A1 - Petretto, G.
A1 - Naik, Aakash
A1 - Esters, M.
A1 - Jackson, A. J.
A1 - Nelson, R.
A1 - Dronskowski, R.
A1 - Rignanese, G.-M.
A1 - Hautier, G.
T1 - Cover profile for the article "Automated bonding analysis with crystal orbital Hamilton populuations"
N2 - Invited for this month’s cover are researchers from Bundesanstalt für Materialforschung und -prüfung (Federal Institute for Materials Research and Testing) in Germany, Friedrich Schiller University Jena, Université catholique de Louvain, University of Oregon, Science & Technology Facilities Council, RWTH Aachen University, Hoffmann Institute of Advanced Materials, and Dartmouth College. The cover picture shows a workflow for automatic bonding analysis with Python tools (green python). The bonding analysis itself is performed with the program LOBSTER (red lobster). The starting point is a crystal structure, and the results are automatic assessments of the bonding situation based on Crystal Orbital Hamilton Populations (COHP), including automatic plots and text outputs. Coordination environments and charges are also assessed. More information can be found in the Research Article by J. George, G. Hautier, and co-workers.
KW - Automation
KW - Chemical bonds
KW - High-throughput
PY - 2022
DO - https://doi.org/10.1002/cplu.202200246
SN - 2192-6506
SP - 1
EP - 2
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - New chemical understanding with the help of automation and highthroughput computations
N2 - High-throughput computations are nowadays an established way to suggest new candidate materials for applications to experimentalists. Due to new packages for automation and access to databases of computed materials properties, these studies became more and more complex over the last years. Besides suggesting new candidate materials for applications, they also offer a way to understanding the materials properties based on chemical bonds. For example, we have recently used orbital-based bonding analysis to understand the results of high-throughput studies for spintronic materials, ferroelectric materials and photovoltaic materials in detail. To do so, we have developed Python tools for high-throughput bonding analysis with the programs VASP and Lobster (see www.cohp.de). They are based on the Python packages pymatgen, atomate, and custodian. This implementation will be discussed within the talk. We also expect that these tools offer possibilities to arrive at new descriptors based on chemical bonds for materials properties.
T2 - High-throughput workflows for materials science with the Atomic Simulation Environment (ASE) and Fireworks
CY - Lyngby, Denmark
DA - 15. November 2021
KW - Automation
KW - High-throughput computations
KW - DFT
PY - 2021
AN - OPUS4-53840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suarez Ocano, Patricia
T1 - Exploring the impact of heat treatment on room and high temperature strength of 316L stainless steel fabricated by PBF-LB
N2 - Laser Powder Bed Fusion (PBF-LB/M) enables the fabrication of 316L stainless steel components with superior strength and intricate geometries. The alloy PBF-LB/M/316L features a fully austenitic microstructure with hierarchical characteristics— such as fine dislocation structures, segregated elements, low-angle grain boundaries, and nano-dispersed silicates—that enhance strength and ductility. Additionally, it includes metallurgical defects and residual stresses. Apart from process control, heat treatments (HTs) are used to tailor the microstructure for specific loading conditions. This study investigate the effects of post-processing HTs on the hierarchical microstructure and tensile properties of PBF-LB/M/316L at room and high temperature. The heat treatments, ranging from 400 °C to 900 °C for 1 to 4 hours, focus on sub-recrystallization temperatures to preserve the microstructural hierarchy. The HTs applied had minimal impact on the grain shape, size, or texture of PBF-LB/M/316L. However, significant modifications occurred in the solidification cellular substructure after HTs at 800 °C and 900 °C, when compared to a heat-treated condition at 450 °C. HTs at 800 °C notably decreased dislocation density and enlarged cellular structures, though they remained partially intact. After 1 hour at 900 °C, the cellular substructure dissipated, correlating with a further reduction in dislocation density. These microstructural changes resulted in a decreased yield strength and increased work hardening capacity at both room and high temperature, highlighting the critical link between HT parameters, microstructural evolution, and mechanical performance.
T2 - The 20th International Conference on Strength of Materials (ICSMA 20)
CY - Kyoto, Japan
DA - 02.06.2025
KW - Additive manufacturing
KW - 316L stainless steel
KW - Heat treatments
KW - Tensile properties
KW - Microstructure
PY - 2025
AN - OPUS4-63914
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bayerlein, Bernd
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
A1 - Birkholz, Henk
A1 - Portella, Pedro Dolabella
A1 - Skrotzki, Birgit
T1 - FAIR and Structured Data: A Domain Ontology Aligned with Standard‐Compliant Tensile Testing
N2 - The digitalization of materials science and engineering (MSE) is currently leading to remarkable advancements in materials research, design, and optimization, fueled by computer‐driven simulations, artificial intelligence, and machine learning. While these developments promise to accelerate materials innovation, challenges in quality assurance, data interoperability, and data management have to be addressed. In response, the adoption of semantic web technologies has emerged as a powerful solution in MSE. Ontologies provide structured and machine‐actionable knowledge representations that enable data integration, harmonization, and improved research collaboration. This study focuses on the tensile test ontology (TTO), which semantically represents the mechanical tensile test method and is developed within the project Plattform MaterialDigital (PMD) in connection with the PMD Core Ontology. Based on ISO 6892‐1, the test standard‐compliant TTO offers a structured vocabulary for tensile test data, ensuring data interoperability, transparency, and reproducibility. By categorizing measurement data and metadata, it facilitates comprehensive data analysis, interpretation, and systematic search in databases. The path from developing an ontology in accordance with an associated test standard, converting selected tensile test data into the interoperable resource description framework format, up to connecting the ontology and data is presented. Such a semantic connection using a data mapping procedure leads to an enhanced ability of querying. The TTO provides a valuable resource for materials researchers and engineers, promoting data and metadata standardization and sharing. Its usage ensures the generation of finable, accessible, interoperable, and reusable data while maintaining both human and machine actionability.
KW - Data Interoperability
KW - Domain Ontology Development
KW - FAIR Data Management
KW - Knowledge Representation
KW - Tensile Test Ontology
KW - Semantic Web Technologies
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598142
DO - https://doi.org/10.1002/adem.202400138
SN - 1438-1656
SP - 1
EP - 19
PB - Wiley VHC-Verlag
AN - OPUS4-59814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fareed, Adnan
A1 - Rosalie, Julian
A1 - Kar, Satyakam
A1 - Fähler, Sebastian
A1 - Maaß, Robert
T1 - Small-scale functional fatigue of a Ni-Mn-Ga Heusler alloy
N2 - Functional fatigue of shape-memory alloys is a considerable threat to the reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipation amounts to about 1/5 of the bulk counterpart and remains unaffected during cycling, even after the introduction of dislocation structures via plastic straining. Plastic yielding and the transformation stress largely exceed the known bulk values. However, the transformation-stress is found to depend on plastic pre-straining, which suggests that the size-affected transformation stress is sensitive to the initial defect structure and that it can be tuned by a targeted introduction of dislocations. These findings demonstrate the high suitability of Ni-Mn-Ga as a robust shape-memory alloy in small-scale functional device engineering.
KW - Superelasticity
KW - Shape-memory alloys
KW - Functional fatigue
KW - Ni-Mn-Ga
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600695
DO - https://doi.org/10.1016/j.actamat.2024.119988
VL - 274
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-60069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Hanke, T.
A1 - Weber, M.
A1 - Eisenbart, M.
A1 - Bauer, F.
A1 - Meissner, R.
A1 - Dziwis, G.
A1 - Tikana, L.
A1 - Chen, Yue
A1 - Skrotzki, Birgit
T1 - Toward a digital materials mechanical testing lab
N2 - To accelerate the growth of Industry 4.0 technologies, the digitalization of mechanical testing laboratories as one of the main data-driven units of materials processing industries is introduced in this paper. The digital lab infrastructure consists of highly detailed and standard-compliant materials testing knowledge graphs for a wide range of mechanical testing processes, as well as some tools that enable the efficient ontology development and conversion of heterogeneous materials’ mechanical testing data to the machine-readable data of uniform and standardized structures. As a basis for designing such a digital lab, the mechanical testing ontology (MTO) was developed based on the ISO 23718 and ISO/IEC 21838-2 standards for the semantic representation of the mechanical testing experiments, quantities, artifacts, and report data. The trial digitalization of materials mechanical testing lab was successfully performed by utilizing the developed tools and knowledge graph of processes for converting the various experimental test data of heterogeneous structures, languages, and formats to standardized Resource Description Framework (RDF) data formats. The concepts of data storage and data sharing in data spaces were also introduced and SPARQL queries were utilized to evaluate how the introduced approach can result in the data retrieval and response to the competency questions. The proposed digital materials mechanical testing lab approach allows the industries to access lots of trustworthy and traceable mechanical testing data of other academic and industrial organizations, and subsequently organize various data-driven research for their faster and cheaper product development leading to a higher performance of products in engineering and ecological aspects.
KW - General Engineering
KW - General Computer Science
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582698
DO - https://doi.org/10.1016/j.compind.2023.104016
SN - 0166-3615
VL - 153
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-58269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zia, Ghezal Ahmad Jan
A1 - Hanke, Thomas
A1 - Skrotzki, Birgit
A1 - Völker, Christoph
A1 - Bayerlein, Bernd
T1 - Enhancing Reproducibility in Precipitate Analysis: A FAIR Approach with Automated Dark-Field Transmission Electron Microscope Image Processing
N2 - AbstractHigh-strength aluminum alloys used in aerospace and automotive applications obtain their strength through precipitation hardening. Achieving the desired mechanical properties requires precise control over the nanometer-sized precipitates. However, the microstructure of these alloys changes over time due to aging, leading to a deterioration in strength. Typically, the size, number, and distribution of precipitates for a quantitative assessment of microstructural changes are determined by manual analysis, which is subjective and time-consuming. In our work, we introduce a progressive and automatable approach that enables a more efficient, objective, and reproducible analysis of precipitates. The method involves several sequential steps using an image repository containing dark-field transmission electron microscopy (DF-TEM) images depicting various aging states of an aluminum alloy. During the process, precipitation contours are generated and quantitatively evaluated, and the results are comprehensibly transferred into semantic data structures. The use and deployment of Jupyter Notebooks, along with the beneficial implementation of Semantic Web technologies, significantly enhances the reproducibility and comparability of the findings. This work serves as an exemplar of FAIR image and research data management.
KW - Industrial and Manufacturing Engineering
KW - General Materials Science
KW - Automated image analysis
KW - FAIR research data management
KW - Reproducibility
KW - microstructural changes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593905
DO - https://doi.org/10.1007/s40192-023-00331-5
SN - 2193-9772
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
CY - Heidelberg
AN - OPUS4-59390
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Piesker, Benjamin
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Rehmer, Birgit
A1 - Agudo Jácome, Leonardo
A1 - Hilgenberg, Kai
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature
N2 - This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters.
KW - Additive manufacturing
KW - Fatigue damage
KW - Heat treatment
KW - Inconel 718
KW - Laser powder bed fusion
KW - Low-cycle fatigue
KW - Tensile strength
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599316
DO - https://doi.org/10.1002/adem.202302122
SN - 1527-2648
SP - 1
EP - 17
PB - Wiley
AN - OPUS4-59931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Chaudry, Mohsin Ali
A1 - Scheuschner, Nils
A1 - Blasón Gonzalez, Sergio
A1 - Madia, Mauro
A1 - Hilgenberg, Kai
T1 - Thermal history transfer from complex components to representative test specimens in laser powder bed fusion
N2 - Additively manufactured components are characterized by heterogeneous mechanical properties due to variations of the microstructure, flaws and residual stresses resulting from the inhomogeneous fabrication process. The large number of influencing factors poses a further challenge in understanding the correlation between material properties, process parameters and component geometry. Therefore, the qualification of components based on witness specimens produced within the same job is questionable. This work aims to present a new strategy for the characterization of PBF-LB/M components based on representative specimens. The key assumption is the feasibility of a transfer of the thermal history from a component to a specimen. It is assumed that similar material properties are determined for components and specimens produced adopting a similar thermal history. After the definition of a region of interest in the component, a combination of thermal analyses by means of finite elements and in-situ experimental determination of the thermal history through infrared thermography is used to produce test coupons with a similar thermal history. The effectiveness of the procedure is demonstrated on a pressure vessel for applications in the chemical industry.
KW - Additive manufacturing
KW - Heat accumulation
KW - Thermal history
KW - In situ monitoring
KW - Process simulation
KW - Representative specimens
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602651
DO - https://doi.org/10.1007/s40964-024-00689-8
SN - 2363-9512
SN - 2363-9520
SP - 1
EP - 16
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-60265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fornacon-Wood, C.
A1 - Stühler, M. R.
A1 - Gallizioli, C.
A1 - Manjunatha, B. R.
A1 - Wachtendorf, Volker
A1 - Schartel, Bernhard
A1 - Plajer, A. J.
T1 - Precise construction of weather-sensitive poly(ester-alt-thioesters) from phthalic thioanhydride and oxetane
N2 - We report the selective ring opening copolymerisation (ROCOP) of
oxetane and phthalic thioanhydride by a heterobimetallic Cr(III)K
catalyst precisely yielding semi-crystalline alternating poly(esteralt-
thioesters) which show improved degradability due to the
thioester links in the polymer backbone.
KW - Sulfur containing polymers
KW - Durability
KW - Weathering
KW - Synthesis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590762
DO - https://doi.org/10.1039/d3cc03315e
SN - 1364-548X
VL - 59
IS - 76
SP - 11353
EP - 11356
PB - RSC
AN - OPUS4-59076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Ávila Calderón, Luis
T1 - Mechanisches Verhalten von additiv gefertigtem nichtrostendem Stahl X2CrNiMo17-12-2 (AISI 316L) und Vergleich zur konventionell gefertigten Variante
T1 - Mechanical behavior of additively manufactured stainless steel X2CrNiMo17-12-2 (AISI 316L) and comparison with a conventionally manufactured variant
N2 - Die additive Fertigung (AM) metallischer Werkstoffe ist eine Technologie, die zunehmend Gegenstand von Forschungsaktivitäten und industrieller Anwendung ist. Dennoch steht sie noch vor Herausforderungen, um eine breite Nutzung in sicherheitsrelevanten Anwendungen zu erreichen. Die Hauptgründe für die Verzögerung des technologischen Durchbruchs zugunsten von AM-Metallen gegenüber konventionell hergestellten Varianten sind das Fehlen eines tieferen Verständnisses der Prozess-Struktur-Eigenschafts-Beziehungen und die begrenzte Verfügbarkeit von Daten zu den Materialeigenschaften. In diesem Kontext stellt diese Arbeit einen Beitrag sowohl zum Verständnis der Prozess-Struktur-Eigenschafts-Beziehungen als auch zur Verbesserung der Datenlage von 316L dar, einem häufig als Konstruktionswerkstoff in verschiedenen Hochtemperaturbauteilen verwendeten Werkstoff. Die Arbeit legt den Fokus auf die mittels Laser-Pulverbettschmelzen hergestellte Werkstoffvariante, PBF-LB/M/316L. Eine konventionell hergestellte Variante, HR/316L, wurde auch untersucht. Bei PBF-LB/M/316L wurde zusätzlich der Effekt ausgewählter Wärmebehandlungen ausgewertet. Die Untersuchung umfasste die Charakterisierung der mechanischen Eigenschaften und der Verformungs- und Schädigungsmechanismen bei erhöhten Prüftemperaturen bei LCF und Kriechen, wo die Daten und Wissenslage am spärlichsten ist. Außerdem hat die untersuchte PBF-LB/M/316L-Wersktoffvariante einen geringen Porositätsgrad. Somit hat diese Arbeit die Mikrostruktur stärker in den Fokus genommen als die meisten bisher in der Literatur verfügbaren Studien.
Die mechanische Prüfkampagne umfasste Zugversuche zwischen Raumtemperatur und 650 °C, LCF-Versuche zwischen Raumtemperatur und 600 °C sowie Kriechversuche bei 600 °C und 650 °C. In Ermangelung konkreter Richtlinien und Normen wurde die Charakterisierung zumeist anhand der bestehenden internationalen Prüfnormen und Probengeometrien durchgeführt. Aus jedem dieser Prüfverfahren wurden die entsprechenden Festigkeits- und Verformungskennwerte ermittelt. Darüber hinaus wurde mit Hilfe gezielter mikrostruktureller Untersuchungen ein Beitrag zum Verständnis des Zusammenhangs zwischen der Mikrostruktur und den mechanischen Eigenschaften in Bezug auf die Verformungs- und Schädigungsmechanismen geleistet.
Die Dehngrenze von PBF-LB/M/316L ist etwa doppelt so hoch wie die von HR/316L und dieser Trend setzt sich mit ansteigender Prüftemperatur fort. Die Bruchdehnung ist bei allen Prüftemperaturen geringer. PBF-LB/M/316L weist über den größten Teil der Ermüdungslebensdauer vor allem bei Raumtemperatur höhere zyklische Spannungen als HR/316L auf. Ausschließlich bei den kleinsten Dehnungs-schwingbreiten sind die Ermüdungslebensdauer ausgeprägt kürzer. Das Wechselverformungsverhalten von PBF-LB/M/316L ist durch eine Anfangsverfestigung gefolgt von einer kontinuierlichen Entfestigung charakterisiert, welche bis zum Auftreten der zum Versagen führenden Entfestigung stattfindet. Die Kriechbruchzeiten und die Dauer jeder Kriechphase sind bei allen Kombinationen von Prüfparametern bei PBF-LB/M/316 kürzer als bei HR/316L. Die Spannungsabhängigkeit von PBF-LB/M/316L ist im Vergleich zu HR/316L geringer und die Duktilität beim Kriechen kleiner. Die minimale Kriechrate wird bei allen geprüften Parameterkombinationen bei deutlich geringeren Kriechdehnungen erreicht. Eine Wärmebehandlung bei 450 °C / 4 h bewirkt keine wesentliche Änderungen der Mikrostruktur und Zugversuchseigenschaften. Eine zusätzliche Wärmebehandlung bei 900 °C / 1 h verursacht eine Abnahme der Dehngrenze des PBF-LB/M/316L. Diese blieb aber immer noch um den Faktor 1,5x höher als bei HR/316L. Die Verformungsmerkmale wurden kaum davon beeinflusst. Bezüglich des Kriechverhaltens hat die Wärmebehandlung bei 900 °C / 1 h längere sekundäre und tertiäre Kriechstadien bewirkt und die Kriechdehnung hat sich signifikant erhöht. Die Bruchbilder unterscheiden sich generell nicht nur aber vor allem mit ansteigender Prüftemperatur, bei der bei PBF-LB/M/316L oft interkristalline Rissbildung beobachtet wurde. Die Zellstruktur trägt als der Hauptfaktor zu den unterschiedlichen mechanischen Eigenschaften im Vergleich zur HR/316L-Variante bei. Darüber hinaus spielen mutmaßlich die Kornmorphologie, die Stapelfehlerenergie und der Stickstoffgehalt eine Rolle.
N2 - Metal additive manufacturing (AM) is a technology that is increasingly the subject of research activities and industrial applications. However, it still faces challenges to achieve widespread use in safety-relevant applications. The main reasons for the delay of this technological breakthrough in favor of AM metals over conventionally manufactured variants are the lack of a deeper understanding of process-structure-property relationships and the limited availability of data on material properties. In this context, this work contributes to both achieving a better understanding of process-structure-property relationships and the improvement of data for 316L, an alloy frequently used as a structural material in various high-temperature components. The work focuses on a material variant produced by laser pow-der bed fusion, PBF-LB/M/316L. A conventionally produced variant, HR/316L, was also investigated. For PBF-LB/M/316L, the effect of selected heat treatments was also evaluated. The investigation included the characterization of the mechanical properties and the related deformation and damage mechanisms at elevated test temperatures in LCF and creep, where data and knowledge are scarce. The PBF-LB/M/316L variant studied has a low degree of porosity. Thus, this work is more focused on the microstructure than most studies available in the literature.
The mechanical test campaign included tensile tests between room temperature and 650 °C, LCF tests between room temperature and 600 °C, and creep tests at 600 °C and 650 °C. In the absence of concrete guidelines and standards for testing of AM metals, the characterization mostly took place using existing international test standards and specimen geometries. From each of the test methods, corresponding strength, and deformation characteristic values were determined. In addition, targeted microstructural investigations contributed to understanding the relationship between the microstructure and the mechanical properties in terms of deformation and damage mechanisms.
The proof stress of PBF-LB/M/316L is about twice that of HR/316L. This trend remains with increasing test temperature. The elongation after fracture is lower at all test temperatures. Regarding LCF, PBF-LB/M/316L exhibits higher cyclic stresses than HR/316L for most of the fatigue life, especially at room temperature. Exclusively at the smallest strain amplitudes, the fatigue lives of PBF-LB/M/316L are markedly shorter than in HR/316L. The cyclic stress-strain deformation behavior of PBF-LB/M/316L features an initial strain hardening followed by a continuous softening, which occurs until the softening leading to failure takes place. The creep rupture times and the duration of each creep stage are shorter for PBF-LB/M/316 than for HR/316L for all combinations of test parameters. The stress dependence of PBF-LB/M/316L is lower, and the creep ductility is smaller compared to HR/316L. The minimum creep rate is reached at significantly lower creep extensions for all parameter combinations tested. A heat treatment at 450 °C / 4 h did not cause significant changes in the microstructure and tensile behavior. An additional heat treatment at 900 °C / 1 h caused a decrease in the proof stress of PBF-LB/M/316L. However, it still remained higher than the one of HR/316L by a factor of 1.5x. The deformation characteristics were hardly affected. Regarding the creep behavior, this latter heat treatment at 900 °C / 1 h caused longer secondary and tertiary creep stages, and the creep strain increased significantly. The fracture characteristics generally differed, which happened not only but especially with increasing test temperature, where intergranular cracking often took place in PBF-LB/M/316L. The cellular structure is considered the main factor contributing to the different mechanical properties compared to the HR/316L variant. In addition, grain morphology, stacking fault energy, and nitrogen content might play a role.
KW - AGIL
KW - Additive Fertigung
KW - Laser-Pulverbettschmelzen
KW - Mikrostrukturentwicklung
KW - 316L
KW - LCF
KW - Kriechen
KW - Additive Manufacturing
KW - Microstructure
KW - Mechanical Properties
KW - Mechanische Eigenschaften
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597143
DO - https://doi.org/10.14279/depositonce-19828
SP - 1
EP - 190
CY - Berlin
AN - OPUS4-59714
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meinderink, D.
A1 - Kielar, C.
A1 - Sobol, Oded
A1 - Ruhm, L.
A1 - Rieker, F.
A1 - Nolkemper, K.
A1 - Orive, A. G.
A1 - Özcan Sandikcioglu, Özlem
A1 - Grundmeier, G.
T1 - Effect of PAA-induced surface etching on the adhesion properties of ZnO nanostructured films
N2 - Zinc oxide - polymer interfaces are known to exhibit interesting properties regarding molecular adhesion. This work is aimed at the investigation of the effect of the morphology and surface chemistry on the macroscopic adhesion of a model epoxy-based adhesive to nanorod (ZnO NR) and nanocrystalline (ZnO NC) ZnO-modified surfaces. Both ZnO films have been prepared using hydrothermal synthesis on hot-dip galvanized steel (HDG) surfaces by varying the precursor chemistry in order to control the film morphology. Poly (acrylic acid) (PAA) was used to improve the interfacial adhesion by modifying the morphology and surface chemistry of ZnO nanostructured films. The strong interaction of PAA from a dilute and neutral aqueous solution with the ZnO nanocrystallites was shown to significantly improve the interfacial adhesion by means of a nanoetching process.
It was shown that the wet peel-forces correlate well with the considered morphology and surface chemistry.
KW - Interfacial stability
KW - Morphology control
KW - Poly(acrylic acid)
KW - Adhesion by mechanical interlocking
KW - ZnO films
KW - ZnO nanorods Nanocrystalline
PY - 2021
DO - https://doi.org/10.1016/j.ijadhadh.2021.102812
SN - 0143-7496
VL - 106
SP - 102812
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-52600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Haubrich, J.
A1 - Requena, G.
A1 - Madia, Mauro
T1 - Influence of post-process heat treatments on the fatigue crack propagation behaviour of a PBF-LB/M AlSi10Mg alloy
N2 - The microstructure has a great influence on short fatigue crack growth in metallic materials. Laser-based Powder Bed Fusion AlSi10Mg alloys exhibit in the as-built condition a fine fibrous Si structure and a supersaturated solid solution of Si in the α-Al matrix, which is significantly modified by heat treatments starting already at temperatures under 260 °C. This study focuses on the influence of post-process heat treatments on the microstructural evolution and the resulting fatigue crack growth resistance. As compared to the as-built condition, two heat treatments at 265 °C/1 h and at 300 °C/2 h are found to be beneficial to the fatigue crack growth resistance of the investigated material.
KW - Additive manufacturing
KW - Fatigue crack growth
KW - Cyclic R-curve
KW - Heat treatment
PY - 2023
DO - https://doi.org/10.1016/j.ijfatigue.2023.107808
SN - 0142-1123
VL - 175
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-57822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beygi Nasrabadi, Hossein
T1 - Domain-level ontology formulation based on the Platform Material Digital (PMD) ontology: case study Brinell hardness
N2 - A large amount of publicly available data is reproduced every day in the field of materials science, while these kind of material data can have different formats and types like paper-type publications, standards, datasheets or isolated datasets in repositories. However, gathering a specific library from such extensive and diverse material data is always challenging for the materials scientists and engineers, since the time-related limitations are not allowed to fully access the large publicly available databases; search across these disparate databases, manage the large volumes of heterogeneous datasets, and integrate data from multiple sources. To address these challenges and make data findable, accessible, interoperable, and reusable (FAIR), an efficient data management system is necessary to build comprehensive, documented, and connected data spaces in the future. A formal standardized knowledge representation through an ontology can address such problems and make data more available and interoperable between related domains. Ontology can also rich machine processable semantic descriptions that increases the performance of scientific searches. In this regard, the Platform MaterialDigital (PMD) is currently working on developing a high-level ontology for the materials and material related processes. For example, in one of the PMD projects of “KupferDigital”, we will try to develop a data ecosystem for digital materials research based on ontology-based digital representations of copper and copper alloys. As a case study, this paper describes the methodology for ontology development of Brinell hardness, based on PMD core ontology. The methodology we describe includes the following steps; gathering the required domain terminology from different resources like standards (DIN EN ISO 6506-1) and test reports, representing the performance of a standard-conformant hardness test and the treatment of the recorded values up to a “reportable” hardness value for a material, designing the process chain according to the semantic technologies, and developing a domain-level ontology of Brinell hardness based on PMD ontology semantic formalization. Apart the mentioned methodology, some interesting tools and methods were introduced and ontology design challenges and possible solutions for modelling materials and processes were discussed. Furthermore, a dataset from the Brinell hardness measurement of cast copper samples is prepared for testing the query process.
T2 - MSE 2022
CY - Darmstadt, Germany
DA - 27.09.2022
KW - Copper
KW - Materials Science
KW - Ontology
KW - Platform MaterialDigital (PMD)
KW - Brinell hardness
PY - 2022
AN - OPUS4-56092
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bär, Jürgen
T1 - Determination of the Kitagawa-Takahashi Diagram using DC Potential Drop Measurements
N2 - The Kitagawa-Takahashi Diagram is an important tool for describing the fatigue limit of components containing defects. The models used for its description differ, particularly in the transition region corresponding to the short crack regime. Therefore, for a reliable statement about the fatigue limit in this area, an experimental validation of the curve is necessary. However, the standardized stair-case method requires a large number of samples and has a long test duration. In this work, a method is presented that allows a simpler and faster validation of the Kitagawa-Takahashi Diagram in the region of short cracks.
Notches with a defined width and depth were manufactured in flat samples of a low-alloyed steel with two different heat treatments using an engraving laser. This method allows to produce very sharp notches without plastic deformation and with only a slight thermal influence on the surrounding material. The samples prepared in this way were fatigued with block wise increasing loads until failure. Cracks are detected by means of a direct current potential drop method. The length of the loading block (number of cycles) is determined by the measured potential drop. This procedure enables a reliable and precise determination of the limit stress for the respective notch size with a low experimental effort and time consumption.
T2 - 5th International Symposium on Fatigue Design and Material Defects
CY - Trento, Italy
DA - 14.05.2025
KW - Fatigue limit
KW - Material defects
KW - Kitagawa-Takahashi Diagram
KW - DC Potential Drop
PY - 2025
AN - OPUS4-63145
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Digitalisierung der Materialien in PMD & Mat-o-Lab - Eine normkonforme Anwendungsontologie des Zugversuchs
N2 - Zur Bewältigung der Herausforderung bei der Digitalisierung von Materialien und Prozessen ist eine mit allen Stakeholdern konsistente Kontextualisierung von Materialdaten anzustreben, d.h. alle erforderlichen Informationen über den Zustand des Materials einschließlich produktions- und anwendungsbezogener Änderungen müssen über eine einheitliche, maschinenlesbare Beschreibung verfügbar gemacht werden. Dazu werden Wissensrepräsentationen und Konzeptualisierungen ermöglichende Ontologien verwendet. Erste Bemühungen in den beiden Projekten Plattform Material Digital und Materials-open-Laboratory führten zur Erstellung von Anwendungsontologien, die Prozesse und Testmethoden explizit beschreiben. Dabei wurde u.a. der Zugversuch an Metallen bei Raumtemperatur nach DIN EN ISO 6892-1 ontologisch beschrieben. Diese als Beispiel dienende Ontologieentwicklung wird in dieser Präsentation vorgestellt.
T2 - Werkstoffprüfung 2021
CY - Online meeting
DA - 02.12.2021
KW - Ontologie
KW - Semantisches Web
KW - Wissensrepräsentation
KW - Digitalisierung
KW - Zugversuch
PY - 2021
AN - OPUS4-53929
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drexler, A
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Rhode, Michael
A1 - Domitner, J
A1 - Sommitsch, C
A1 - Böllinghaus, Thomas
T1 - Enhanced gaseous hydrogen solubility in ferritic and martensitic steels at low temperatures
N2 - Metals that are exposed to high pressure hydrogen gas may undergo detrimental failure by embrittlement. Understanding the mechanisms and driving forces of hydrogen absorption on the surface of metals is crucial for avoiding hydrogen embrittlement. In this study, the effect of stress-enhanced gaseous hydrogen uptake in bulk metals is investigated in detail. For that purpose, a generalized form of Sievert's law is derived from thermodynamic potentials considering the effect of microstructural trapping sites and multiaxial stresses. This new equation is parametrized and verified using experimental data for carbon steels, which were charged under gaseous hydrogen atmosphere at pressures up to 1000 bar. The role of microstructural trapping sites on the parameter identification is critically discussed.
KW - Hydrogen
KW - Thermodynamic modelling
KW - Pressure-dependent solubility
KW - Steel
KW - Trapping
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559307
DO - https://doi.org/10.1016/j.ijhydene.2022.09.109
SN - 0360-3199
VL - 47
IS - 93
SP - 39639
EP - 39653
PB - Elsevier Ltd.
AN - OPUS4-55930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tan, Yi
A1 - Wachtendorf, Volker
A1 - Klack, Patrick
A1 - Kukofka, Tobias
A1 - Ruder, J.
A1 - Schartel, Bernhard
T1 - Durability of the flame retardance of ethylene-vinyl acetate copolymer cables: Comparing different flame retardants exposed to different weathering conditions
N2 - Scientific publications addressing the durability of the flame retardance of cables during their long-term application are rare and our understanding lacks. Three commercial flame retardants, aluminum hydroxide, aluminum diethyl phosphinate (AlPi-Et), and intumescent flame retardant based on ammonium polyphosphate, applied in ethylene-vinyl acetate copolymer (EVA) model cables, are investigated. Different artificial aging scenarios were applied: accelerated weathering (UV-irradiation/temperature/rain phases), humidity exposure (elevated temperature/humidity), and salt spray exposure. The deterioration of cables’ surface and flame retardancy were monitored through imaging, color measurements, attenuated total reflectance Fourier transform infrared spectroscopy, and cone calorimeter investigations. Significant degradation of the materials’ surface occurred. The flame retardant EVA cables are most sensitive to humidity exposure; the cable with AlPi-Et is the most sensitive to the artificial aging scenarios. Nevertheless, substantial flame retardance persisted after being subjected for 2000 h, which indicates that the equivalent influence of natural exposure is limited for several years, but less so for long-term use.
KW - Durability
KW - Flame retardant
KW - Cable
KW - Weathering
KW - Cone calorimeter
PY - 2020
DO - https://doi.org/10.1002/APP.47548
SN - 0021-8995
VL - 137
IS - 1
SP - 47548
PB - Wiley
AN - OPUS4-50237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Putra, Stephen Nugraha
A1 - Rethmeier, Michael
T1 - Numerical analysis of the influence of an auxiliary oscillating magnetic field on suppressing the porosity formation in deep penetration laser beam alloys of aluminum alloys
N2 - The contactless magnetohydrodynamic technology has been considered as a potential and promising method to improve the weld qualities of deep penetration laser beam welding. In this paper, numerical investigations are conducted to study the influence of the auxiliary oscillating magnetic field on the porosity suppression in laser beam welding of 5754 aluminum alloy. To obtain a deeper insight into the suppression mechanism, a three-dimensional transient multi-physical model is developed to calculate the heat transfer, fluid flow, keyhole dynamic, and magnetohydrodynamics. A ray tracing algorithm is employed to calculate the laser energy distribution on the keyhole wall. A time-averaged downward Lorentz force is produced by an oscillating magnetic field. This force acts in the molten pool, leading to a dominant downward flow motion in the longitudinal section, which blocks the bubble migration from the keyhole tip to the rear part of the molten pool. Therefore, the possibility for the bubbles to be captured by the solidification front is reduced. The electromagnetic expulsive force provides an additional upward escaping speed for the bubbles of 1 m/s ~ 5 m/s in the lower and middle region of the molten pool. The simulation results are in a good agreement with experimental measurements. Based on the results obtained in this study, a better understanding of the underlying physics in laser beam welding enhanced by an auxiliary oscillating magnetic field can be provided and thus the welding process can be further optimized reducing the porosity formation.
T2 - 13th International Seminar Numerical Analysis of Weldability
CY - Seggau, Austria
DA - 04.09.2022
KW - Deep penetration laser beam welding
KW - Oscillating magnetic field
KW - Numerical simulation
KW - Porosity
KW - Molten pool behaviour
PY - 2023
SN - 2410-0544
VL - 13
SP - 237
EP - 254
PB - Verlag der Technischen Universität Graz
AN - OPUS4-58804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fabry, Çağtay
T1 - WelDX – Entwicklung und Anwendung eines einheitlichen Dateiformates für das Lichtbogenschweißen
N2 - Ziel des WelDX Forschungsvorhabens ist es, den Austausch wissenschaftlicher Forschungsdaten aus dem Bereich der Schweißtechnik auf Basis eines einheitlichen Open Source Dateiformates zu ermöglichen und damit die Einhaltung und Dokumentation geeigneter Qualitätsstandards zu fördern. Im Zuge der Projektarbeit wird die Zusammenarbeit und der Wissenstransfer schweißtechnischer Institute zunächst auf nationaler Ebene gefördert und die Bildung eines von der Fachcommunity getragenen Kuratoriums zur Betreuung und Weiterentwicklung des Dateiformates und der Ausarbeitung zugehöriger Qualitätsstandards angestrebt.
T2 - DVS AG V 2.8 Workshop "Lichtbogenphysik"
CY - Krefeld, Germany
DA - 10.03.2020
KW - Schweißen
KW - Forschungsdatenmanagement
KW - Open science
KW - Open data
KW - Digitalisierung
PY - 2020
AN - OPUS4-50679
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittner, Andreas
A1 - Fabry, Çağtay
A1 - Hirthammer, Volker
A1 - Rethmeier, Michael
T1 - Open Science in der Schweißtechnik
N2 - Darstellung der aktuellen Situation sowie des Potenzials von Forschungsdatenmanagement und OpenScience in der Schweißtechnik.
T2 - WelDX - Open Science Seminar
CY - BAM Berlin, Germany
DA - 04.03.2020
KW - Digitalisierung
KW - Schweißtechnik
KW - OpenScience
KW - Forschungsdatenmanagement
PY - 2020
UR - https://www.bam.de/Content/DE/Veranstaltungen/2020/2020-03-09-weldx-open-science-seminar.html
AN - OPUS4-51857
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Thermal Cycles and Charpy Impact Toughness of Single-Pass Hybrid Laser-Arc Welded Thick-Walled Structures
N2 - The study deals with the influence of the heat input on the thermal cycles and Charpy impact toughness for hybrid laser-arc welding of 25 mm thick structural steel S355J2 using a 20-kW high-power laser in combination with an electromagnetic weld pool support. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured using a pyrometer in combination with an optical fibre in three different locations near to fusion lines corresponding to different heights of the seam. Also, Charpy impact specimens were taken from different parts of the weld joint corresponding to the different heights. The influence of the heat input was investigated for 1.8 kJ mm-1 and 3.2 kJ mm-1. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required values could be reached in dependance on applied heat input.
T2 - Lasers in Manufacturing Conference 2021
CY - Online meeting
DA - 21.06.2021
KW - laser hybrid welding
KW - Charpy impact toughness
KW - thick plate welding
KW - thermal cycles
PY - 2021
SP - 1
EP - 8
AN - OPUS4-53926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ávila Calderón, Luis
T1 - IUC02: Framework for Curation & Distribution of Reference Datasets (On the example of Creep Data of Ni Based superalloys)
N2 - A research data management framework to conceptualize & implement a digital infrastructure for the Generation, Distribution, and Utilization of reference datasets of materials is presented. The documentation of the test data is often incomplete. This concerns, e.g., material’s manufacturing process or chemical composition, or test equipment’s description and its calibration status. Our concept addresses this issue by proposing the implementation of a requirements profile. A crucial part of the concept is to reach a community-agreement on the definition of reference data and on the underlying data schema and vocabulary. In this presentation a general workflow overview and the relevance of selected individual subworkflows is presented.
T2 - MSE Research Data Forum 2025
CY - Siegburg, Germany
DA - 08.07.2025
KW - NFDI MatWerk
KW - Referenzdaten
KW - Kriechen
PY - 2025
AN - OPUS4-64881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neumann, Benedikt
A1 - Biegler, Max
A1 - Goecke, Sven-Frithjof
A1 - Rethmeier, Michael
T1 - Detektion von Bindefehlern beim DED-Arc
T1 - Detection of Lack of Fusion during DED-Arc
N2 - Based on artificial intelligence (AI) developed for monitoring arc welding, this article presents a deep neural network for monitoring lack of fusion defects in wire arc additive manufacturing of aluminium. The aim is to detect defects in built-up volumes on the basis of weld source data. These can be successfully processed by the algorithm presented and a trained AI. The achieved accuracy of the network is 90 percent.
N2 - In dem Beitrag wird aufbauend auf Machine-Learning-Modellen, welche bereits zum Überwachen des Schutzgasschweißen erforscht wurden, ein tiefes neuronales Netz (DNN) zum Monitoring beim DED-Arc von Aluminium vorgestellt. Ziel ist die Detektion von Bindefehlern in den aufgebauten Volumina auf Grundlage von in Echtzeit gemessenen Schweißstromquellensignalen. Es werden Merkmalsvariablen durch Vorverarbeitung extrahiert sowie die Korrelation zwischen den Merkmalsvariablen und den Defekten analysiert. Durch den vorgestellten Algorithmus werden diese automatisiert als Input an ein DNN übergeben. Das entwickelte und trainierte neuronale Netz erkennt anhand signifikanter Merkmale aus den Strom- und Spannungsdaten Bindefehler mit einer Genauigkeit von ca. 90 Prozent.
KW - DED-Arc
KW - Aluminiumschweißen
KW - Bindefehler
KW - Prozessüberwachung
KW - Maschinelles Lernen
KW - Deep Neural Network
PY - 2024
DO - https://doi.org/10.1515/zwf-2024-1107
VL - 8
SP - 577
EP - 583
PB - Walter de Gruyter GmbH
AN - OPUS4-61630
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raute, J.
A1 - Marquardt, R.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Untersuchung zum Elektronenstrahlschweißen additiv gefertigter Ni-Basis-Bauteile
N2 - Die vorliegende Untersuchung befasst sich mit dem Einfluss des Additive Manufacturing auf die Schweißeignung von Bauteilen aus Inconel 718. Hierfür wurden Proben mittels DED und L-PBF hergestellt und ihr Verhalten in Blindschweißversuchen anhand eines Vergleichs mit konventionellen Gussblechen untersucht. Im zweiten Schritt wurden die verschiedenen additiv hergestellten Proben mit dem Gussmaterial im I-Stoß sowie untereinander verschweißt.
Als Schweißverfahren wurde für alle Proben das Elektronenstrahlschweißen angewandt. Zur Auswertung wurde anhand von Schliffen das Nahtprofil vermessen und die Proben auf Poren und Risse untersucht. Zusätzlich wurde die Dichte vermessen und eine Prüfung auf Oberflächenrisse durchgeführt. Das AM-Material zeigte dabei Unterschiede in Nahtform und Defektneigung im Vergleich zum Gusswerkstoff. Insbesondere die DED-proben neigten unter bestimmten Parameterkonstellationen verstärkt zu Porenbildung. Risse konnten nicht beobachtet werden. Trotz auftretender Nahtunregelmäßigkeiten wurde in den kombinierten AM-Schweißproben die Bewertungsgruppe C erreicht. Eine Prüfung der bestehenden Regelwerke zur Schweißnahtbewertung anhand der gewonnenen Erkenntnisse zu additiv gefertigten Proben im Elektronenstrahlschweißprozess zeigte keinen Ergänzungsbedarf.
T2 - #additivefertigung: Metall in bestForm
CY - Essen, Germany
DA - 26.10.2022
KW - Elektronenstrahlschweißen
KW - Additive Fertigung
KW - Schweißnahtbewertung
PY - 2022
SN - 978-3-96144-202-7
VL - 383
SP - 81
EP - 92
PB - DVS-Media GmbH
AN - OPUS4-56173
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Chunliang
T1 - Numerical analysis of ultrasonic vibration enhanced friction stir welding of dissimilar Al/Mg alloys
N2 - The ultrasonic vibration enhanced friction stir welding (UVeFSW) process has unique advantages in joining dissimilar Al/Mg alloys. While there are complex coupling mechanisms of multi-fields in the process, it is of great significance to model this process, to reveal the influence mechanism of ultrasonic vibration on the formation of Al/Mg joints.
In this study, the acoustic-plastic constitutive equation was established by considering the influence of both ultrasonic softening and residual hardening on the flow stress at different temperatures and strain rates. And the ultrasonic induced friction reduction (UiFR) effect on friction coefficient in different relative directions at the FSW tool-workpiece interface was quantitatively calculated and analyzed.
The Al/Mg UVeFSW process model was developed through introducing the above acoustic effects into the model of Al/Mg friction stir welding (FSW). The ultrasonic energy is stronger on the aluminum alloy side. In the stirred zone, there is the pattern distribution of ultrasonic sound pressure and energy. The heat generation at the tool-workpiece contact interface and viscous dissipation were reduced after applying ultrasonic vi-bration. Due to the UiFR effect, the projection of friction coefficient and heat flux distributions at the tool-workpiece interface present a "deformed" butterfly shape. The calculated results show that ultrasonic vibration enhanced the material flow and promoted the mixing of dissimilar materials.
T2 - The 13th International Seminar "Numerical Analysis of Weldability"
CY - Graz, Austria
DA - 04.09.2022
KW - Numerical simulation
KW - Friction stir welding
KW - Ultrasonic vibration
KW - Al/Mg alloys
PY - 2022
AN - OPUS4-56319
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abel, Andreas
T1 - Microstructure-Property-Correlation of a Mo-Ti-B alloyed iron aluminide
N2 - Iron aluminides depict a sustainable and light-weight material class which could be employed in many applications requiring high strength at intermediate to high temperatures. According to first results, the alloy Fe-26Al-4Mo-0.5Ti-1B surpasses conventional materials in wet corrosion resistance and creep resistance up to 650 °C. For these reasons, the AiF research project “WAFEAL – Materials applications for iron aluminides” was initiated to transfer these findings into a standardised materials dataset and to derive best practices for processing. In the first place, a set of different microstructures adjusted by varying casting methods, wall thicknesses and heat treatments was investigated and correlated with hardness on macro and micro scale. Correlations were drawn between solidification rates and resulting grain sizes and hardness. The effect of vacancy hardening was only verified for wall thickness as low as 2.5 mm. Moreover, a common decrease of macrohardness after a heat treatment at 1000 °C for 100 h was observed irrespective of casting process or wall thickness. This effect was linked with an unexpected decrease of the complex boride phase fraction which acts as a hardening phase.
T2 - Intermetallics 2021
CY - Bad Staffelstein, Germany
DA - 04.10.2021
KW - Fe-Al alloys
KW - Intermetallics
KW - Iron aluminides
KW - Heat treatment
KW - Wall thickness
KW - Centrifugal casting
KW - Die casting
KW - Investment casting
KW - Microstructure
KW - Hardness
KW - Complex borides
PY - 2021
AN - OPUS4-53617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
A1 - Naik, Aakash
T1 - DFT raw data for "Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: Evidence for and DFT simulation of a radiation-induced phase"
N2 - DFT raw data for the publication https://doi.org/10.1039/D2TC01773C
It includes all predicted structures, the structure optimizations and the phonon computations in VASP format. Phonon computations were performed with the finite displacement method.
KW - DFT
KW - Phonons
KW - Structure prediction
PY - 2022
DO - https://doi.org/10.5281/zenodo.5942729
PB - Zenodo
CY - Geneva
AN - OPUS4-55417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Skrotzki, Birgit
A1 - Schriever, Sina
T1 - BAM reference data - Results of ASTM E139-11 creep tests on a reference material of Nimonic 75 nickel-base alloy
N2 - Results of creep tests on a certified reference material at T = 600°C and a tensile creep load of 160 MPa are provided. The evaluated results include the times to reach 2% and 4% creep strain, respectively, and the creep rate after 400 h.
The data were audited and are BAM reference data.
KW - Reference data
KW - Creep
KW - Nickel-base alloy
KW - Nimonic 75
KW - Reference material BCR-425
PY - 2021
DO - https://doi.org/10.5281/zenodo.5106606
PB - Zenodo
CY - Geneva
AN - OPUS4-52970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
A1 - Zerbst, Uwe
A1 - Madia, Mauro
T1 - Vergleichende Untersuchungen zum intrinsischen Schwellenwert der da/dN-ΔK-Kurve
N2 - Für die Bestimmung der Restlebensdauer zyklisch beanspruchter Bauteile kommt dem Schwellenwert für Ermüdungsrissausbreitung, Δ𝐾𝑡ℎ, und dem sich anschließenden Schwellenwertbereich der 𝑑𝑎𝑑𝑁⁄−Δ𝐾-Kurve große Bedeutung zu. Dem stehen Unsicherheiten bei der Bestimmung und Analyse gegenüber. Der Aufsatz befasst sich mit der Ermittlung des sogenannten intrinsischen Schwellenwerts, der als robuster Eingangsparameter für eine „rissschließfreie“ Analyse der Restlebensdauer von entscheidender Bedeutung ist.
T2 - 53. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 18.02.2021
KW - Schadenstolerante Bauteilauslegung, Restlebensdauer, intrinsischer Schwellenwert gegen Ermüdungsrissausbreitung
PY - 2021
SN - 2366-4797
SP - 211
EP - 220
PB - Deutscher Verband für Materialforschung und -prüfung e.V. (DVM)
CY - Berlin
AN - OPUS4-52704
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Fatigue Crack Growth of Heat Resistant Austenitic Cast Iron under Isothermal and Anisothermal Conditions
N2 - The heat-resistant cast iron EN-GJSA-XNiSiCr35-5-2 (Ni-Resist D-5S) was investigated for its fatigue crack growth behavior at room and high temperatures. Force-controlled tests were carried out at constant temperatures (20 °C, 500 °C, 700 °C) without and with hold time and different load ratios. The crack growth behavior was also characterized under TMF loading (Tmin = 400 °C, Tmax = 700 °C) by applying IP and OP conditions and different load ratios. Three different techniques were combined to monitor crack growth: potential drop, thermography, and compliance method. The effect of the different loading conditions on the fatigue crack growth behavior will be presented and discussed.
T2 - TMF Workshop 2024
CY - Berlin, Germany
DA - 25.04.2024
KW - Fatigue crack growth
KW - Thermomechanical fatigue
KW - Austenitic cast iron
KW - Ni-Resist
PY - 2024
AN - OPUS4-59964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Towards the Use of Representative Specimens for the Qualification of Additively Manufactured Parts
N2 - The understanding of the process-structure-property-performance relationship is the key challenge for the qualification of safety-relevant parts made of additively manufactured metallic materials. The complexity of the manufacturing process and the number of influencing parameters affect the properties of test coupons and parts even fabricated in the same batch. This poses the problem of using reliable witness specimens for part qualification.
This work presents a new approach which aims at the fabrication of test coupons tailored to the specific microstructure and fatigue properties of a component. The first step consisted in the evaluation of the temperature field by means of process monitoring during the production of parts. The results were used to tailor finite element models which were then used to design witness specimens representative of the thermal history in the component. Finally, the fatigue properties of designed specimens were compared to coupons machined out of the component.
T2 - TMS2024 – 153rd Annual Meeting & Exhibition
CY - Orlando, FL, USA
DA - 03.03.2024
KW - Additive Manufacturing
KW - Process simulation
KW - Thermal history
KW - Structural integrity
KW - Damage tolerance
PY - 2024
AN - OPUS4-65072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
T1 - Numerical study on the formation of a bulging region in partial penetration laser beam welding
N2 - A transient three-dimensional thermo-fluid dynamics numerical model was developed to study the formation of a bulging region in partial penetration laser beam welding. The model accounts for the coupling between the fluid flow, the heat transfer, and the keyhole dynamics by considering the effects of multiple reflections and Fresnel absorption of the laser beam in the keyhole, the phase transitions during melting and evaporating, the thermo-capillary convection, the natural convection, and the phase-specific and temperature-dependent material properties up to the evaporation temperature. The validity of the model was backed up by experimentally obtained data, including the drilling time, the weld pool length, the local temperature history outside the weld pool, the process efficiency, and a range of metallographic cross-sections. The model was applied for the cases of partial penetration laser beam welding of 8 mm and 12 mm thick unalloyed steel sheets. The obtained experimental and numerical results reveal that the bulging region forms transiently depending on the penetration depth of the weld, showing a tendency to transition from a slight bulging to a fully developed bulging region between penetration depths of 6 mm and 9 mm, respectively.
T2 - The 13th International Seminar "Numerical Analysis of Weldability"
CY - Graz - Castle Seggau, Austria
DA - 04.09.2022
KW - Laser beam welding
KW - Deep penetration
KW - Bulge formation
KW - Numerical modeling
PY - 2022
AN - OPUS4-55719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Vojtek, T.
A1 - Duarte, Larissa
A1 - Zerbst, Uwe
A1 - Pokorný, P.
A1 - Jambor, M.
A1 - Hutař, P.
T1 - Determination of fatigue crack propagation thresholds for steel in presence of environmental effects
N2 - The experimental determination of the resistance to fatigue crack propagation in steel, particularly in the socalled near-threshold regime, is a crucial issue for safety-relevant components which are designed to operate for a large number of loading cycles before undergoing periodic inspections. This work summarizes the most relevant results of extensive experimental campaigns conducted at BAM and IPM over the last years, which have been devoted to the determination of fatigue crack propagation characteristics on medium and high strength steels. The influence of environment, oxide-induced crack closure and test methodologies in the near-threshold regime are discussed.
KW - Steel
KW - Fatigue crack propagation threshold
KW - Oxide-induced crack closure
KW - Environmental effect
PY - 2021
DO - https://doi.org/10.1016/j.ijfatigue.2021.106449
SN - 0142-1123
VL - 153
SP - 1
PB - Elsevier Ltd.
AN - OPUS4-53525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Hennecke, M.
ED - Skrotzki, Birgit
T1 - Hütte Band 1: Mathematisch-naturwissenschaftliche und allgemeine Grundlagen für Ingenieure
N2 - Die HÜTTE ist ein Kompendium und Nachschlagewerk für unterschiedliche Aufgabenstellungen. Durch Kombination der Einzeldisziplinen dieses Wissenskreises kann das multidisziplinäre Grundwissen für die verschiedenen Technikbereiche und Ingenieuraufgaben zusammengestellt werden.
Die HÜTTE enthält in drei Bänden - orientiert am Stand von Wissenschaft und Technik und den Lehrplänen der Technischen Universitäten und Hochschulen - die Grundlagen des Ingenieurwissens.
Band 1 enthält die mathematisch-naturwissenschaftlichen und allgemeinen Grundlagen.
KW - Mathematisch-naturwissenschaftliche Grundlagen
KW - Allgemeine Grundlagen
PY - 2022
SN - 978-3-662-64368-6
DO - https://doi.org/10.1007/978-3-662-64369-3
SN - 2522-8188
SP - 1
EP - 895
PB - Springer Vieweg
CY - Berlin
ET - 35
AN - OPUS4-56234
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Zugversuchsdaten FAIR integriert: Von der normenkonformen Ontologie bis zu interoperablen Daten im Triple Store
N2 - Mit der Digitalisierung von Materialien und Prozessen ist ein Paradigmenwechsel in der Materialentwicklung, -gestaltung und -optimierung verbunden, welcher gleichermaßen vielseitige Möglichkeiten eröffnet und eine große Herausforderung darstellt. Insbesondere sind bei den Digitalisierungsbestrebungen die Qualitätssicherung von Prozessen und Ausgabedaten sowie die Interoperabilität zwischen Anwendungen nach FAIR-Prinzipien (Findability, Accessibility, Interoperability, Reusability) sicherzustellen. Dies umfasst die Speicherung, Verarbeitung und Abfrage von Daten in möglichst standardisierter Form, wobei entsprechend auch Normungs- und Standardisierungsgremien beteiligt werden müssen. Um der Herausforderung gerecht zu werden, Materialdaten für alle Beteiligten konsistent zu kontextualisieren, müssen alle notwendigen Informationen zum Zustand des Materials inklusive produktions- und anwendungsbedingter Veränderungen über eine einheitliche, maschinenlesbare Beschreibung verfügbar gemacht werden. Hierfür sollen Ontologien genutzt werden, da sie maschinenverständliche und -interpretierbare Wissensrepräsentationen durch semantische Konzeptualisierungen ermöglichen, die für das Datenmanagement und die Digitalisierung im Bereich der Materialwissenschaften benötigt werden.
Dieses hochaktuelle Thema der Integration und Wiederverwendung von Wissen und Daten aus Herstellung, Bearbeitung und Charakterisierung von Materialien wird in den Projekten Innovationsplattform MaterialDigital (PMD, materialdigital.de) und Materials-open-Lab (Mat-o-Lab, matolab.org) adressiert. Diese beiden unter der Beteiligung der Bundeanstalt für Materialforschung und -prüfung (BAM) durchgeführten Projekte wurden auf der 39. Vortrags- und Diskussionstagung „Werkstoffprüfung“ (2021) grundlegend vorgestellt. In dieser Präsentation sollen die Weiterentwicklungen hinsichtlich der Speicherung von Zugversuchsdaten gemäß einer normenkonformen ontologischen Repräsentation vorgestellt werden. Das umfasst den Weg von der Entwicklung einer Ontologie nach Norm, der Konvertierung von Daten aus Standardtests in das interoperable RDF-Format bis hin zur Verknüpfung von Ontologie und Daten. Letztendlich können die entsprechenden Daten in einem Triple Store abgelegt und abgefragt werden.
Die übliche Standardisierung von mechanischen Prüfverfahren im Bereich der Materialwissenschaft und Werkstofftechnik dient als solide Grundlage für die Ontologieentwicklung. Daher wurde der Zugversuch von Metallen bei Raumtemperatur nach DIN EN ISO Norm 6892-1:2019-11 als einer der ersten Anwendungsfälle in den genannten Projekten ausgewählt. Die Betrachtung und Beschreibung des Zugversuchs beinhaltet sowohl dessen ontologische Darstellung als auch eine exemplarische Datengenerierung. Die semantische Verbindung von Ontologie und Daten führt zu Interoperabilität und einer verbesserten Abfragefähigkeit.
T2 - Tagung Werkstoffprüfung 2022
CY - Dresden, Germany
DA - 27.10.2022
KW - Ontologie
KW - Semantisches Web
KW - Wissensrepräsentation
KW - Digitalisierung
KW - Zugversuch
PY - 2022
AN - OPUS4-56130
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Ermüdungsrisswachstum von warmfestem austenitischem Gusseisen unter isothermen und anisothermen Belastungen
N2 - Das Ermüdungsrisswachstumsverhalten des warmfesten Gusseisens EN-GJSA-XNiSiCr35-5-2 (auch unter der Bezeichnung Ni-Resist D-5S bekannt) wurde bei Raum- und hoher Temperatur untersucht. Es wurden kraftgeregelte Versuche bei konstanten Temperaturen (20 °C, 500 °C, 700 °C) ohne und mit Haltezeit und unterschiedlichen Lastverhältnissen durchgeführt. Zusätzlich wurde das Risswachstumsverhalten auch unter TMF-Belastung (Tmin = 400 °C, Tmax = 700 °C) unter IP- und OP-Bedingungen charakterisiert. Die Überwachung des Rissfortschritts erfolgte durch die Kombination von drei verschiedenen Techniken: Potenzialabfall, Thermografie und Compliance-Methode. Die Auswirkungen der verschiedenen Belastungsbedingungen auf das Ermüdungsrisswachstum werden vorgestellt und diskutiert.
T2 - Bauteilverhalten bei thermomechanischer Ermüdung
CY - Berlin, Germany
DA - 25.03.2025
KW - Gusseisen
KW - Thermomechanische Ermüdung
KW - Rissfortschritt
KW - Risswachstum
KW - Ermüdungsriss
KW - Thermographie
PY - 2025
AN - OPUS4-63185
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Damage tolerant design of metallic AM parts
N2 - Additive Manufacturing (AM) opens new possibilities in the design of metallic components, including very complex geometries (e.g. structures optimized for certain loads), optimization of materials (e.g. gradient materials) and cost-effective manufacturing of spare parts. In the recent years, it has been used for the first safety-relevant parts, but the consideration of cyclic mechanical behavior in AM is still at the very beginning. The reason for this is the complexity of mechanical material properties, i.e. inhomogeneity, anisotropy and a large number of defects frequently textured and characterized by large scattering in size. Additionally, high surface roughness and residual stresses with complex distributions are typical of AM. Due to these reasons, the transferability of experimentally determined properties from specimens to components is a challenge. This presentation provides an overview of the questions concerning the application of AM to safety-relevant components. Possible strategies for the fatigue design of such components are presented. Besides the Kitagawa-Takahashi-diagram method and the cyclic R-curve analysis as approaches for damage-tolerant design, the identification of critical locations, the problem of representative material properties and the handling of residual stresses are addressed.
T2 - 4th international symposium on Fatigue Design and Material Defects
CY - Online meeting
DA - 26.05.2020
KW - Additive Manufacturing
KW - Cyclic R-Curve
KW - Component assessment
PY - 2020
AN - OPUS4-50938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Preparing and structuring experimental laboratory data for the publication of reference data
N2 - Using a practical example, this contribution provides an insight into the procedure for processing and structuring experimental elastic modulus data (Young's modulus, E, shear modulus, G), which were determined using the resonance method for three different metallic materials [1]. The data were internally audited as BAM reference data. By reference data, we mean research data that have been measured (or simulated) to a particularly high standard and are well-documented concerning material processing, testing, and data evaluation.
The datasets include information on processing routes and parameters, heat treatments, grain size, specimen dimensions, weight, and Young’s and shear modulus along with their measurement uncertainty. The processing routes and measuring methods are described in detail. The data structure is shown in Fig. 1. The datasets were generated in an accredited testing lab and are hosted in the open data repository Zenodo [2-4].
The comprehensive documentation of the metadata, which is linked to the intended usages of the dataset, and the sharing in a machine-readable structured format in an open repository represents an important step towards fulfilling the FAIR (Findability, Accessibility, Interoperability, Reusable) principles. The publication of a data descriptor article increases the visibility of the dataset in the targeted community.
T2 - MSE2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Reference data
KW - Young's modulus
PY - 2024
AN - OPUS4-61144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Jonathan
T1 - High resolution visual in-situ process monitoring in SONRISA
N2 - The LuFo Project "SONRISA" presented an update on its objectives for the coming years to Working Group 3 – In-Situ Process Monitoring – during the EASA/FAA Additive Manufacturing Workshop 2025. As part of this update, BAM provided a brief overview of its prior work in high-resolution visual in-situ process monitoring for PBF-LB/M, which will be integrated into the project. The presentation included a comparison between the BAM system and the OEM in-situ monitoring system “EOSTATE PowderBed” and an outline of the correlation between texture contrast and the occurrence of lack-of-fusion anomalies in high resolution after exposure images.g.
T2 - EASA–FAA AM Workshop 2025
CY - Cologne, Germany
DA - 21.10.2025
KW - Additive manufacturing
KW - High resolution camera
KW - Lack of fusion
PY - 2025
AN - OPUS4-64456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - A numerical study on the suppression of a detrimental weld pool profile in wire feed laser beam welding by magnetohydrodynamic technique
N2 - The weld quality and the possible defect formation are directly determined by the weld pool shape and the thermo-fluid dynamics therein. In this paper, an untypical weld pool profile, i.e., elongated at its top and bottom but narrowed at the middle, is found experimentally and numerically in the wire feed laser beam welding. The detrimental influence of the weld pool narrowing on the element transport is analyzed and discussed. A magnetohydrodynamic technique is utilized to suppress the narrowing, aiming at a more homogenous element distribution. It is found that a low-temperature region is formed in the middle of the weld pool due to the interaction of the two dominant circulations from the top and bottom regions. The weld pool is significantly narrowed due to the untypical growth of the mushy zone in the low-temperature region, which results in a direct blocking effect on the downward flow and the premature solidification in the middle region. The Lorentz force produced by a transverse oscillating magnetic field shows the potential to change the flow pattern into a single-circulation type and the low-temperature-gradient region is mitigated.
Therefore, the downward transfer channel is widened, and its premature solidification is prevented. The numerical results are well validated by experimental measurements of metal/glass observation and X-ray fluorescence element mapping.
T2 - 13th International Seminar Numerical Analysis of Weldability
CY - Seggau, Austria
DA - 04.09.2022
KW - Thermo-fluid flow
KW - Element transport
KW - Laser beam welding
KW - Magnetohydrodynamics
KW - Multi - physical modeling
PY - 2023
SN - 2410-0544
VL - 13
SP - 143
EP - 160
PB - Verlag der Technischen Universität Graz
AN - OPUS4-58806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
ED - Bastian, P.
ED - Dranzlmüller, D.
ED - Brüchle, H.
ED - Mathias, G.
T1 - Accelerated Materials Discovery with Automation and MachineLearned Chemical Knowledge
N2 - This project aims to accelerate the search for new materials (e.g., for thermoelectric applications, battery materials, magnets, and other materials classes) based on ab initio highthroughput studies. Highthroughput searches are typically restricted to known materials. This project explores strategies (datadriven chemical heuristics in subproject 1 and machinelearned interatomic potentials in subproject 2) to go beyond current database entries and include such computationally demanding properties in highthroughput searches. To accomplish each subproject, we develop automated workflows for highthroughput computations and provide large open databases of computed materials properties to the research community.
KW - Automation
KW - Chemically Complex Materials
KW - Machine Learning
KW - Machine-Learned Interatomic Potentials
KW - Workflows
PY - 2024
UR - https://doku.lrz.de/files/10745976/1136429625/1/1731329162337/2024_SuperMUC-Results-Reports.pdf
SN - 978-3-9816675-6-1
SP - 72
EP - 75
AN - OPUS4-61618
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Fatigue Strength of Aerospace Parts Repaired by Cold Spray
N2 - Aerospace components are safety critical parts, which are often replaced when found defective after the fabrication process or after periodic inspection in-service. Cold spray repair is a promising and cost-saving alternative to replacing worn parts. Depositing materials in decent quality fill machined damage volumes can enhance the performance of refurbished parts and extend their working life. Furthermore, repair represents a resource-efficient and green process in a world targeting at decarbonization of many industrial sectors.
Component repair consists of a defined sequence of operations. First, damage is removed by machining, then new material is applied by cold spray on the machined substrate. Usually, the original functional shape of the component is restored by machining. Post-spraying heat treatments can be applied where required. Despite the advantages, cold spray repair still suffers from major limitations which prevent its application in safety relevant parts. The main challenges are posed by the poor adhesion strength, the porosity inherent in the manufacturing process, the reduced ductility and the presence of residual stresses. This work presents recent results obtained in the frame of the cluster project CORE devoted to the development of automatized repair of aerospace parts by cold spray. The investigations consider high-strength aluminum alloys typically used in structural applications in the aerospace industry. As the fatigue properties are crucial to the safe application of repaired components, and given the presence of process-induced defects, a damage tolerant framework is peculiarly suitable for the structural integrity assessment of repaired commponents and give an indication of the permissible defects to optimize the parameters of the cold spray process. Several high cycle fatigue and fatigue crack propagation tests have been performed to compare the fatigue performance of base and repaired materials. The mechanical tests are corroborated by fractographic and microstructural investigations.
T2 - ICAM2024
CY - Atlanta, GA, USA
DA - 28.10.2024
KW - Cold Spray
KW - Aerospace
KW - Repair
KW - Structural Integrity
KW - Fatigue Strength
PY - 2024
AN - OPUS4-61539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical studies of magnetohydrodynamic technology in suppressing process porosity during laser beam welding
N2 - The magnetohydrodynamic (MHD) technology is employed to mitigate the porosity problem during partial penetration laser beam welding (LBW) of 10 mm thick aluminum alloy. The effectiveness and universal applicability of the MHD technology in reducing porosity during the LBW process are confirmed by a reduction in the porosity ratio of more than 89%. A transient 3D multi-physical model coupled with the MHD effect has been developed to investigate the suppression mechanism of process porosity. Due to the influence of Lorentz force, there is an obvious change in the weld pool length. This change widens the escaping channel of bubbles escaping from the weld pool. The application of an oscillating magnetic field changes the fluid flow pattern noticeably, whose influence on the formation of porosity defects is highly complicated and nonlinear.
T2 - 13th CIRP Conference on Photonic Technologies
CY - Nuremberg, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Aluminum alloy
KW - Process Porosity
KW - Porosity suppression
KW - Magnetohydrodynamic technology
PY - 2024
AN - OPUS4-61604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Smales, G. J.
T1 - DACHS-MOFs Database for Automation, Characterisation, and Holistic Synthesis
N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS MOFs focuses on the synthesis and characterisation of metal-organic frameworks (MOFs), across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF syntheses. So far > 1200 MOF samples have been synthesised, with SAXS/WAXS data currently being collected on all samples. All results, including those from “failed” syntheses, are included in the database, as results are results and should be considered agnostic to any positive ornegative interpretations. DACHS MOFs represents the initial trial of the DACHS project, serving as a comprehensive resource for researchers aiming to optimize the synthesis and characterization of MOFs.
T2 - XIX International Small Angle Scattering Conference
CY - Taipei, Taiwan
DA - 04.11.2024
KW - Lab automation
KW - Synthesis
KW - Metal organic frameworks
KW - Zif-8
KW - Databases
KW - Synthesis data
PY - 2024
AN - OPUS4-61626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ávila Calderón, Luis
A1 - Schriever, Sina
T1 - BAM Reference Data: Creep of Single-Crystal Ni-Based Superalloy CMSX-6
N2 - This publication provides comprehensive metadata and test results of constant force creep tests according to DIN EN ISO 204:2019-4 on the single crystal Ni-based superalloy CMSX-6 at T = 980 °C and initial stresses between 140 MPa and 230 MPa. The tests were carried out in an accredited test laboratory using calibrated measuring equipment. The data were audited and are BAM reference data.
KW - NFDI-MatWerk
KW - Digitalisierung
KW - CMSX-6
KW - Creep
KW - Reference Data
KW - Referenzdaten
KW - Ni-Based Superalloy
PY - 2024
DO - https://doi.org/10.5281/zenodo.13937986
PB - Zenodo
CY - Geneva
AN - OPUS4-61649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Miliūtė, Aistė
T1 - Synthesis and phase purity of the negative thermal expansion material ZrV2O7
N2 - This repository contains computational and experimental data for the manuscript titled “Synthesis and phase purity of the negative thermal expansion material ZrV2O7”.
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - XRD
KW - Raman
PY - 2024
DO - https://doi.org/10.5281/zenodo.12688634
PB - Zenodo
CY - Geneva
AN - OPUS4-61360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
T1 - Materialinformatik
N2 - Die Materialinformatik ermöglicht es, vorhandenes/etabliertes chemisches Wissen zu überprüfen, aber auch neues Wissen zu generieren. Zu diesem Zweck wurden automatisierte Methoden entwickelt, die es ermöglichen, große Datenbanken mit Materialeigenschaften zu berechnen. Diese Datenbanken mit berechneten Eigenschaften können nun mit Datenanalysetechniken und maschinellem Lernen ausgewertet werden. Unsere Entwicklungen ermöglichen es insbesondere, die Analyse der chemischen Bindung mit anderen Materialeigenschaften in großem Maßstab zu kombinieren. Auf der Grundlage von Deskriptoren für chemische Bindungen haben wir die ersten Schritte zur Entwicklung neuer chemischer Regeln unternommen. Daneben entwickeln wir weitere Programmcodes, die die Tätigkeiten in der Materialinformatik deutlich erleichtern
KW - Materialdesign
KW - Maschinelles Lernen
KW - Automatisierung
KW - Hochdurchsatz
KW - Workflows
KW - Materialeigenschaften
PY - 2024
SN - 978-3-8007-6472-3
SP - 14
EP - 32
CY - Berlin
AN - OPUS4-62256
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Naik, Aakash
T1 - Enhancing material property predictions using quantum chemical bonding descriptors
N2 - The properties of crystalline materials, such as elasticity, ionic conductivity, and thermal conductivity, are influenced by interactions between their constituent atoms.[1–3] These interactions, which are often quantified in terms of bond strength, can be extracted from crystalline materials using density-based[4], energy-based[5] and orbital-based methods. LOBSTER[6] is a software that relies on the orbital-based method to extract such bonding information by projecting the plane wave-based wave functions of modern density functional theory computations (DFT) onto a local atomic orbital basis. To garner a better understanding of how this bonding information relates to material properties on a larger scale, machine learning seems an obvious choice. However, for such data-driven studies, large quantities of data need to be systematically generated, validated, and post-processed (e.g., by feature engineering), as they can only then be used as input for state-of-the-art ML models. We have, therefore, previously developed workflows for high-throughput bonding analysis[7]. In this work, we use the results[8] from high-throughput LOBSTER calculations using our workflows to generate bonding-based features. To extract such features from the LOBSTER computations, we use our package LobsterPy.[9] The importance of these features is then tested by employing them in several state-of-the-art ML algorithms and architectures to predict the mechanical and vibrational properties of crystalline materials. We show that including these bonding-based features alongside typical composition and structure-based features helps enhance the model’s predictive accuracy.
T2 - 18th German Conference on Cheminformatics
CY - Bad Soden am Taunus, Germany
DA - 03.11.2024
KW - Bonding analysis
KW - Machine learning
KW - Materials Descriptors
PY - 2024
AN - OPUS4-62217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
T1 - Laser and hybrid welding with ultra high power lasers
N2 - Welding with high-power lasers has a history of over 30 years. With the introduction of high-powerCO2 lasers, the subject was investigated as early as the 1990s as part of various research projects. A renewed interest in the subject was awakened with the market launch of high-brilliance, high-power fibre and disc lasers at the beginning of the 2000s.
In industrial production, the use of high-power lasers for welding shipbuilding constructions at the same time as for mobile crane construction is mainly associated with low-alloy high-strength steels with a maximum wall thickness of 15 mm. The use of high-power multi 10kW lasers for even greater sheet thicknesses (20mm-100 mm) promises significantly greater advantages [1]. For these wall thicknesses the economic, technological and ecological advantages of the process over conventional welding methods become especially clear and visible [2]. Despite numerous research projects on this topic, laser technology still faces a number of hurdles that need to be overcome. The new lasers with scalable laser powers up to 100 kW and the application of an electromagnetic weld pool support as well as local vacuum environment widen the possible application range tremendously.
In this contribution, the authors address the technical solutions for high-power laser beam welding in the field of thick sheet metal applications, highlight the technological and normative challenges in the industrial implementation of the process and present a perspective for the first concrete applications in the field of off-shore wind energy.
T2 - Stuttgarter Laser Tage
CY - Stuttgart, Germany
DA - 04.06.2024
KW - High-power laserbeam welding
KW - Thick plates
KW - Electromagnetic weld pool support
PY - 2024
AN - OPUS4-62412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rethmeier, Michael
T1 - Single pass laser vacuum welding of thick steel plates using electromagnetic support
N2 - The increasing demand for renewable energy produced by offshore wind turbines goes along with an increased demand in the production of offshore wind turbine foundations, so called “monopiles”, which are made by joining thick metal sheets. The industrial standard of multi-layer submerged arc welding (SAW) for joining of thick metal sheets is the current bottleneck in the production of monopiles. A possible increase in productivity by the implementation of high-power laser welding in a newly developed mobile vacuum chamber (MoVac) and an electromagnetic root support is the subject of this study. Single run butt welds are performed in flat position on S355 mild steel of thicknesses up to 80 mm using a disc laser system with 1030 nm wavelength and a maximum output of 60 kW. The laser optic is fixed on the MoVac-System which is held and manipulated by an articulated robot.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Furth, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Laser welding with mobile vacuum
PY - 2024
AN - OPUS4-62413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-Driven Materials Design
N2 - Implementations and algorithms, such as ChemEnv and LobsterEnv, for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are now available. Fully automatic workflows and analysis tools have been developed to use quantumchemical bonding analysis on a large scale. The first part of the lecture will demonstrate how our tools, which assess local atomic environments and perform automatic bonding analysis, help develop new machine-learning models and a new intuitive understanding of material properties. Many new universal machine-learned interatomic potentials, such as MACE-MP-0, have been developed. The second part of the lecture will showcase how these potentials, in combination with DFT, could significantly accelerate our research. The focus will be on the interplay of DFT and machine-learned interatomic potentials, presenting new fully automated workflows for training, finetuning, and implemented benchmarking these potentials, in our software autoplex (https://github.com/autoatml/autoplex). Additionally, I will show how to train new interatomic potentials from scratch by exploring potential energy surfaces extensively, offering a method to enhance current universal machine-learned potentials. Beyond this, the general trend toward automation in computational materials science and some of our recent contributions will be discussed.
T2 - AI4AM2025
CY - Donostia, Spain
DA - 08.04.2025
KW - Automation
KW - Machine Learning
KW - Chemically Complex Materials
KW - Thermal Conductivity
KW - Bonding Analysis
KW - Workflows
KW - Machine Learned Interatomic Potentials
PY - 2025
AN - OPUS4-62950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
T1 - How 3D X-ray Imaging and Residual Stress Analysis contribute to safety of materials and structures
N2 - The safety of materials and structures can be detrimentally influenced by residual stresses (RS) and defect populations (voids or other features leading to failure) if they are not correctly accounted for in the design. Therefore, the accurate characterization of these features and the consideration of their impact is crucial for the safe design of components. The ability to characterize these features non-destructively enables the direct correlation on resulting mechanical performance. 3D X-ray computed tomography (XCT) is used to resolve and quantitively analyze microstructural features (i.e., voids, porosity). This is often used to assess the capability of the manufacturing route, i.e., additive manufacturing (AM). The non-destructive nature of the method also enables the study of the evolution of damage in materials from such microstructural features [1]. Using in-situ methods such as compression or tension, the propagation of damage from initial microstructure can be assessed, aiding our understanding of which features are detrimental to safety [3]. Diffraction based residual stress analysis methods including high energy X-ray and neutron diffraction can be used to study the residual stress gradients from the surface, subsurface and into the bulk non-destructively. These methods can be used to study the influence of heat treatments on residual stress and can be combined with XCT results to correlate the interaction of residual stresses with microstructural features (i.e., void clusters).
This talk will give an overview of the capabilities and opportunities of 3D XCT and diffraction based residual stress analysis to close the gap in our understanding of material degradation on mechanical performance, enabling manufacturers to adjust their designs accordingly for safety critical applications. A particular focus will be made on examples where the two advanced techniques are combined to enhance such understanding.
T2 - MaterialsWeek 2025
CY - Frankfurt am Main, Germany
DA - 02.04.2025
KW - Neutron Diffraction
KW - Residual Stress
KW - X-ray Computed Tomography
KW - Additive Manufacturing
KW - Large Scale facilites
KW - Creep
KW - Defects
KW - BAMline
PY - 2025
AN - OPUS4-62895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hilgenberg, Kai
A1 - Madia, Mauro
T1 - Additive Fertigung von Bauteilen und Strukturen – Grenzen, Risiken, Chancen
N2 - Dieser Eröffnungsvortrag des DVM-Tages beleuchtet Herausforderungen in der additiven Fertigung und plädiert für eine enge Zusammenarbeit von Fertigungstechnik und Bruchmechanik für die Vorhersage der Lebensdauer AM-gefertigter Komponenten.
T2 - DVM-Tag
CY - Berlin, Germany
DA - 08.04.2025
KW - Additive Fertigung
KW - Digitale Qualitätssicherung
KW - Ermüdungsfestigkeit
PY - 2025
AN - OPUS4-62971
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
T1 - How experimental and computational methods allow us to design negative thermal expansion materials
N2 - Combined experimental and computational methods allow comprehensive understanding, design, and tailoring of material properties. We focus on a well-known negative thermal expansion (NTE) material, zirconium vanadate (ZrV2O7), and address synthesis, characterisation and validation of results with computational simulations. Experimental and computational X-ray diffraction and Raman spectroscopy data highlighted differences between phase-pure and multiphase ceramics. These techniques allowed us to distinguish subtle differences in the structure of the material. Based on ab initio simulated phonon data, unaffected by impurities or instrumental errors, we could interpret the Raman spectra and visualise Raman active atom vibrations. These computational models allowed better insight and further experimental improvement while high-quality experimental data granted the validation and improvement of computational simulation strategy.
T2 - Application of Neutrons and Synchrotron Radiation in Engineering Materials Science
CY - Hamburg, Germany
DA - 23.03.2025
KW - NTE
KW - Sol-gel
KW - Ab initio
KW - Raman
KW - XRD
PY - 2025
AN - OPUS4-62832
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, J.
A1 - Madia, Mauro
A1 - Schurig, M.
A1 - Kruse, Julius
A1 - Conrad, F.
A1 - Schlums, H.
A1 - Kontermann, C.
A1 - Zerbst, Uwe
T1 - Anwendung von repräsentativen Proben zur Bewertung der Strukturintegrität von sicherheitsrelevanten Komponenten
N2 - Sicherheitsrelevante Bauteile, bei denen ein Versagen im Betrieb katastrophale Folgen haben könnte, sind in der Regel für eine sehr geringe Ausfallwahrscheinlichkeit ausgelegt und unterliegen strengen Qualifizierungsverfahren gemäß den von den Aufsichtsbehörden festgelegten Richtlinien. Die Hersteller sind oft gezwungen, Tests an realen oder skalierten Komponenten durchzuführen, um die Strukturintegrität unter definierten Belastungsbedingungen sicherzustellen, die in der Regel strenger sind als die im Betrieb zu erwartenden. Dies ist in der Regel mit einem enormen experimentellen und finanziellen Aufwand verbunden. Daher versuchen die Unternehmen, neue Strategien wie digitale Zwillinge zu entwickeln, mit denen die Kosten massiv gesenkt werden können, ohne die Sicherheit zu beeinträchtigen. In dieser Arbeit wird ein neues quasistatisches Prüf- und Bewertungskonzept vorgestellt, dessen Hauptidee darin besteht, die experimentelle Prüfung von Bauteilen durch die Prüfung von für das Bauteil repräsentativen Proben zu ersetzen oder zumindest zu reduzieren. Der größte Vorteil des vorgeschlagenen Konzepts besteht darin, dass die Versuche auf Laborprüfmaschinen durchgeführt werden können. Die Wirksamkeit der Methodik wird anhand der Bewertung der Strukturintegrität einer Turbinenscheibe aus einer Ni-Basis-Superlegierung für Flugzeugtriebwerke bei Überdrehzahl demonstriert.
T2 - 57. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Köln, Germany
DA - 18.02.2025
KW - Strukturintegrität
KW - Bruchmechanik
KW - Turbinenscheibe
KW - Repräsentative Proben
PY - 2025
DO - https://doi.org/10.48447/BR-2025-536
SP - 231
EP - 240
PB - DVM
CY - Berlin
AN - OPUS4-62602
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lemke, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Fließfähigkeitsanalyse zweier Pulverfraktionen aus AISI 316L und resultierende Bauteildichte DED-LB aufgebauter Quader
N2 - Die Fließfähigkeit von Metallpulvern gilt als wichtige Pulvereigenschaft für den additiven Aufbau mittels Laser, wobei bisher wenige Arbeiten die Auswirkungen im Laserpulverauftragschweißen (Engl.: Directed Energy Deposition DED-LB) untersuchen. Arbeiten, die sich mit den Pulvereigenschaften für Pulverbettverfahren beschäftigen, zeigen Korrelationen zwischen Partikelgrößenverteilung und Fließeigenschaften mit der Bauteildichte und den mechanischen Eigenschaften. Sie bewerten insbesondere Pulverbettdichte und -stabilität. In der vorliegenden Arbeit werden daher die Eigenschaften zweier Pulverfraktionen (20 µm – 63 µm und 63 µm – 150 µm) des austenitischen Stahls AISI 316L und deren freien Ausfluss im Vergleich zur Pulverdichte untersucht. Die Untersuchungen zeigen, dass die feinere Pulverfraktion eine um 14,5 % höhere Durchflussrate erzielt als die gröbere Fraktion. korreliert die Ergebnisse zur inneren Porosität und Partikelgrößenverteilung.
Die Analyse der Bauteilqualität zeigt einen geringen Einfluss der Korngrößenverteilung auf die Porosiät der DED-LB aufgebauten Quader.
T2 - 44. Assistentenseminar Fügetechnik der WGF
CY - Päwesin, Germany
DA - 20.09.2023
KW - 316L
KW - Fließfähigkeit
KW - DED-LB
KW - Hall-Flow
KW - Metallpulver
PY - 2024
SP - 131
EP - 140
AN - OPUS4-60723
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Lobster workflow and applications
N2 - This talk introduced bonding analysis to the participants of the school including several examples of its usefulness. Additionally, I talked in detail about the workflows related to bonding analysis within the atomate2 workflow library. I then showed how the workflow was applied to build a very large bonding data database that can now be used for machine learning of materials properties.
T2 - "Automated ab initio workflows with Jobflow and Atomate2" CECAM Flagship school
CY - Lausanne, Switzerland
DA - 17.03.2025
KW - Automation
KW - Materials design
KW - Machine learning
KW - Thermal conductivity
KW - Inorganic materials
KW - High-throughput
PY - 2025
AN - OPUS4-62948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Schönherr, J. A.
T1 - Ermittlung des intrinsischen Schwellenwerts und dessen Validierung als Werkstoffparameter
N2 - Die Anwendung bruchmechanischer Methoden zur schadenstoleranten Bauteilauslegung ist für zyklische Lasten im Bereich der Paris-Geraden Stand der Technik. Technisch relevant sind jedoch häufig geringere Lasten im Schwellenwertbereich der d𝑎/d𝑁-Δ𝐾-Kurve. Aufgrund des großen Einflusses von Rissschließeffekten ist dessen Bestimmung jedoch nicht nur aufwändig, sondern auch potenziell fehlerbehaftet. Die Bauteilauslegung erfolgt zweckmäßigerweise auf der Basis effektiver, d. h. rissschließkorrigierter Rissfortschrittsdaten. Von großer Bedeutung ist auch der intrinsische Schwellenwert, unterhalb dessen keine Risserweiterung mehr eintritt. In diesem Forschungsprojekt erfolgte eine Untersuchung des Einflusses verschiedener Prüfverfahren und Umgebungsbedingungen auf die Ermittlung des Schwellenwerts gegen Ermüdungsrissausbreitung Δ𝐾th. Es wurden statistisch abgesicherte Empfehlungen zur experimentellen Ermittlung des intrinsischen Schwellenwerts Δ𝐾th,eff abgeleitet. Dieser dient auch als Eingangsparameter einer weiterentwickelten Prozedur zur Bauteilauslegung auf der Basis bei einem Lastverhältnis von 𝑅 ≈ 0,8 ermittelter, effektiver, Rissfortschrittsdaten. Es zeigte sich, dass die bei einem Lastverhältnis von 𝑅 ≈ 0,8 in Laborluft bei höherer Prüffrequenzen (≥90 Hz) ermittelten Schwellenwerte eine konservative Abschätzung des intrinsischen Schwellenwerts erlaubten. Bei Lastverhältnissen 𝑅 ≪ 0,8 wurde ein teilweise stark ausgeprägter Einfluss extrinsischer Effekte auf das Rissfortschrittsverhalten festgestellt. Eine Untersuchung der Bruchflächen ergab Oxidschichtdicken in der Größenordnung mehrerer hundert Nanometer. Bei Reduktion der Prüffrequenz auf ≈55 Hz und Prüfung in feuchter Luft (60 % r.F. und 80 % r.F.) konnte auch bei 𝑅 = 0,8 Rissschließen beobachtet werden. Die weiterentwickelte Prozedur zur Bauteilauslegung auf Basis effektiver Rissfortschrittsdaten lieferte aber stets konservative Ergebnisse in einem tolerierbaren Fehlerbereich und ist deshalb zur Anwendung geeignet. Die im Projekt gewonnenen Erkenntnisse tragen zu einer robusten Bauteilauslegung auf bruchmechanischer Basis bei. Der stark reduzierte Versuchsumfang bei Nutzung effektiver Rissfortschrittsdaten gegenüber der Ermittlung von spannungsverhältnisabhängigen Rissfortschrittskurven beschleunigt und vereinfacht die Bauteilauslegung auf Basis bruchmechanischer Methoden.
KW - Schwellenwert gegen Ermüdungsrissausbreitung
KW - Einflussfaktoren auf Rissfortschrittsdaten
KW - Bauteilauslegung
KW - Rissschließeffekte
PY - 2023
SN - 978-3-96780-151-4
SP - 1
EP - 190
PB - Forschungsvereinigung Stahlanwendung e. V.
CY - Düsseldorf
AN - OPUS4-58459
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Ontology-oriented modeling of the Vickers hardness knowledge graph
N2 - This research deals with the development of the Vickers hardness knowledge graph, mapping the example dataset in them, and exporting the data-mapped knowledge graph as a machine-readable Resource Description Framework (RDF). Modeling the knowledge graph according to the standardized test procedure and using the appropriate upper-level ontologies were taken into consideration to develop the highly standardized, incorporable, and industrial applicable models. Furthermore, the Ontopanel approach was utilized for mapping the real experimental data in the developed knowledge graphs and the resulting RDF files were successfully evaluated through the SPARQL queries.
T2 - ICMMM 2023: 10th International Conference on Mechanics, Materials and Manufacturing
CY - Washington, D.C., USA
DA - 18.08.2023
KW - Ontology
KW - Knowledge graph
KW - Data mapping
KW - Vickers hardness
KW - FAIR data
PY - 2023
AN - OPUS4-58100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strommer, Bettina
T1 - Anisotropy in natural rubber / graphene nanocomposites
N2 - The incorporation of nanoscale particles into elastomers enable a boost in performance and/or a distinct reduction of conventional filler loadings due to their high surface to volume ratio. 2D layered nanoparticles like graphene and graphene-related materials provide a great potential as effective fillers in rubber, especially by enhancing mechanical and barrier properties. The type and properties of the nanoparticles, their interface and the elastomeric matrix materials influence the technical behavior, and therefore the potential application fields of such rubber nanocomposites. Especially crucial for the efficiency of the nanofiller, however, is its best possible incorporation into the elastomer. The dispersing of nanoparticles without agglomerates usually constitutes a challenge when using conventional two-roll milling or internal mixing. Academic approaches for highly dispersed nanocomposites solve this problem but are often energy and time consuming with no feasible scale up possibility. Therefore, an ultrasonic assisted NR latex premixing process was established to produce highly filled masterbatches, enabling the main processing with conventional rubber processing techniques.
Two carbon-based nanoparticles with similar specific surface areas were investigated and incorporated in natural rubber as nanocomposites: A commercially available multilayer graphene (MLG) and a nanoscale carbon black (nCB). The mentioned premixed masterbatches were further processed to nanocomposites by the addition of matrix NR, two-roll milling, and hot pressing (vulcanization). By this procedure an increase in Young’s modulus of 157% (MLG) and 71% (nCB) could be obtained at a concentration level of 3 phr. As anisotropic material behavior was observable for the nanocomposites containing MLG, different measurement methods were investigated to quantify the orientation of the nanoparticles in the nanocomposites: Sorption measurements (swelling in 2 dimensions), hardness and dynamical mechanical analysis (in-plane vs. cross-plane), X-Ray diffraction and transmission and scanning electron microscopy.
T2 - DKT IRC 21
CY - Nuremberg, Germany
DA - 27.06.2022
KW - Processing
KW - Elastomers
KW - Nanocomposites
KW - Graphene
KW - Orientation
KW - Anisotropy
PY - 2022
AN - OPUS4-55205
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Interlinking Structured Data about Aging and Fattigue of an Aluminum Alloy
N2 - In typical material oriented research projects numerous types and sources of data need to get connected to form the final outcome. The data-structures have to be described in a manner semantically concise enough so that all participants share the meaning and at the same time flexible enough to allow connecting findings and facts that have not been connected before.
The present contribution describes the approach that is being taken in a public funded research project with two cooperating research institutes. The aim of the data-management solution is to describe and interlink three main entity types: material entities like a test specimen that is under observation, immaterial entities like a fatigue life model and processes that generate and transform the immaterial and material entities.
The shared understanding of what is described by the data is achieved by referring to existing linked data resources. In addition a common thesaurus that is subject to ongoing discussion is used for concepts and terms that need precision beyond publicly available concept descriptions. The data associated with the entities and processes and entities is rather small and well structured. The entities and processes covered by the vocabularies are typical to laboratories performing fatigue testing and microstructure analysis. Through the interlinking of the entities and processes it becomes possible to intuitively understand the knowledge that is accumulating in the database. For example it is easy to trace the history of a creep test specimen starting from the chemical composition that has been analyzed for the heat, continuing with the heat treatment of the material, going into the creep test itself with the associated creep data and finally finding the transmission electron microscopy images that have been taken from the crept sample.
The presented approach is prototypical way to tackle the sustainable management of structured open research data. Open questions remain for example with the management of attributions, the acceptance of an increased effort in data creation and the access control to specific regions of the data. On the other hand the approach sketches what added value can be created, if the community adopts and contributes to the linked data principles.
T2 - LCF9
CY - Berlin, Germany
DA - 21.6.2022
KW - Data management
KW - Data linking
KW - Thesaurus
PY - 2022
AN - OPUS4-55159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Durlo Tambara, Luís Urbano
T1 - Influence of dredging mud on the calcium sulfoaluminate cement hydration
N2 - Dredging sediment refers to materials removed from the bottom of a water body during dredging operations. Mainly the dreading mud contains clay, silt, sand, water, and alkalis. This work incorporated dredging mud into the calcium sulfoaluminate cement at replacement levels of 0%, 10%, 30%, and 50% by weight. Pastes were evaluated after 1d, 28d, and 90d- hydration through mechanical strengths and the reaction rate by isothermal conduction calorimetry. XRD and MIP characterized the reaction products. The findings showed that small replacements (10% and 30%) increased early strength with higher ettringite formation in the system at 1d of curing. However, the evolution of mechanical strength was lower than the reference (0% replacement) over time. The results showed that in low replacement dosages, the dredging mud act as a nucleation site for the hydration of calcium sulfoaluminate phases.
T2 - 7th International Conference Non-Traditional Cement & Concrete (NTCC)
CY - Brno, Czech Republic
DA - 25.06.2023
KW - Calcium sulfoaluminate cement
KW - Dredging mud
KW - Hydration
KW - Paste
PY - 2023
AN - OPUS4-58054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Blasón Gonzalez, Sergio
A1 - Werner, Tiago
A1 - Kruse, Julius
A1 - Gilli, Daniel
A1 - Madia, Mauro
T1 - Experimental procedure for the determination of intrinsic fatigue crack propagation threshold ΔKth,eff and characterization of FCGR curves on miniature steel specimens
N2 - The largest percentage of component life under fatigue loading conditions is spent in the short crack regime and in the initial phase of long cracks. The use of Fracture Mechanics in the characterization of fatigue crack growth rate curves has proven to be a useful and adequate tool in the prediction of fatigue lifetimes as long as certain conditions are satisfied. All the above implies the need for a methodical and accurate procedure of assessment of the material response in order to achieve a reliable prediction of lifetime in components under safe conditions, based on the damage tolerance approach. It also highlights the need to analyse the response of increasingly reduced thicknesses, which, as time goes by, show greater differences with respect to those commonly studied and defined in standards and design guidelines, as well as to the experimental studies that can be found in the literature at present. Some examples of thin-walled components are turbine blades or certain additively manufactured parts where, additionally, variations in material properties can occur locally and should also be examined.
T2 - 2nd International Symposium on Notch Mechanics (2nd ISNM)
CY - Madrid, Spain
DA - 03.09.2020
KW - miniature specimens; FCGR curves; intrinsic threshold
PY - 2021
SP - 1
EP - 2
AN - OPUS4-55242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Skrotzki, Birgit
T1 - Brinell-Hardness (HBW 2.5/62.5) of Al-alloy EN AW-2618A after different aging times and temperatures
N2 - The dataset contains data from Brinell hardness measurements of Al-alloy EN AW-2618A after aging for different times and temperatures. Aging was either load free or with applied tensile load (creep).
KW - Aluminium alloy
KW - EN AW-2618A
KW - Brinell hardness
KW - Aging
KW - Creep
PY - 2022
UR - https://doi.org/10.5281/zenodo.6787085
UR - https://doi.org/10.5281/zenodo.10396823
DO - https://doi.org/10.5281/zenodo.6787084
PB - Zenodo
CY - Geneva
AN - OPUS4-55158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - George, Janine
T1 - DFT-based Phonon-computations for "Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity"
N2 - These are the harmonic phonon and Grüneisen parameter computations for the publication "Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity" (https://doi.org/10.1002/aenm.202200717). VASP and Phonopy outputs are included in this data set.
KW - Thermal conductivity
KW - Phonons
PY - 2021
DO - https://doi.org/10.5281/zenodo.5116360
PB - Zenodo
CY - Geneva
AN - OPUS4-55168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
T1 - High temperature fatigue crack growth in nickel-based alloys joined by brazing and additive manufacturing
N2 - Nickel-based alloys have been widely used for gas turbine blades owing to their excellent mechanical properties and corrosion resistance at high temperatures. The operating temperatures of modern gas turbines have been increased in pursuit of increased thermal efficiency. Turbine blades are exposed to these high temperatures combined with mechanical stresses, resulting in material damage through creep, fatigue, and other mechanisms. These turbine blades must be regularly inspected and replaced as needed, to prevent the loss of efficiency, breakdown, and catastrophic failure. Repair of the damaged turbine blades is often a more practical and cost-effective option than replacement, as replacement is associated with high costs and loss of material resources. To this end, state-of-the-art repair technologies including different additive manufacturing and brazing processes are considered to ensure efficient repair and optimum properties of repaired components.
In any repaired part, materials property-mismatches and/or inner defects may facilitate the crack initiation and propagation and thus reduce the number of load cycles to failure. Therefore, a fundamental understanding of the fatigue crack growth and fracture mechanisms in joining zones is required to enable the prediction of the remaining life of repaired components and to further improve and adapt the repair technologies.
Fatigue crack growth experiments have been conducted on SEN (Single Edge Notch) specimens joined via brazing, and pre-sintered Preform (PSP) and multi-materials (casted/printed) specimens layered via additive manufacturing (AM). The experiments were performed at 950 °C and various stress ratios. The crack growth was measured using DCPD (Direct Current Potential Drop) method. The stress intensity factors for joined SEN specimens were calculated using the finite element method and then used to derive the fatigue crack growth curves. Metallographic and fractographic analyses were conducted to get insight into the fracture mechanism.
Results show that the experimental technique for fatigue crack growth was successfully adapted and applied for testing joined specimens. Furthermore, the initial tests indicate that the investigated braze filler material provides a lower resistance to crack growth, and bonding defects cause a crack to deviate to the interface of the base material and joining zone. In AM-sandwich specimens, the crack growth rates are significantly reduced when the crack reaches the interface of printed material and casted material. The obtained crack growth data can be used to calibrate a crack growth model, which will further be utilized to predict the remaining life of repaired components.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Fatigue crack growth
KW - Joined nickel-based alloys
PY - 2023
AN - OPUS4-58266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Adopting FAIR data practices in materials science: Semantic representation of a quantitative precipitation analysis
N2 - Many metallic materials gain better mechanical properties through controlled heat treatments. For example, in age-hardenable aluminium alloys, the strengthening mechanism is based on the controlled formation of nanometre-sized precipitates, which represent obstacles to dislocation movement and consequently increase the strength. Precise tuning of the material microstructure is thus crucial for optimal mechanical behaviour under service condition of a component. Therefore, analysis of the microstructure, especially the precipitates, is essential to determine the optimum parameters for the interplay of material and heat treatment. Transmission electron microscopy (TEM) is utilized to identify precipitate types and orientations in the first step. Dark-field imaging (DF-TEM) is often used to image the precipitates and thereafter quantify their relevant dimensions. Often, these evaluations are still performed by manual image analysis, which is very time-consuming and to some extent also poses reproducibility problems.
Our work aims at a semantic representation of an automatable digital approach for this material specific characterization method under adaption of FAIR data practices. Based on DF-TEM images of different precipitation states of a wrought aluminium alloy, the modularizable, digital workflow of quantitative analysis of precipitate dimensions is described. The integration of this workflow into a data pipeline concept will also be discussed. Using ontologies, the raw image data, their respective contextual information, and the resulting output data of the quantitative image analysis can be linked in a triplestore. Publishing the digital workflow and the ontologies will ensure data reproducibility. In addition, the semantic structure enables data sharing and reuse for other applications and purposes, demonstrating interoperability.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Semantic Representation
KW - FAIR data management
KW - Quantitative Precipitation Analysis
KW - Knowledge graph and ontologies
PY - 2023
AN - OPUS4-58199
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
T1 - Hollow specimens as simplified approach for testing metallic materials under high pressure hydrogen development and utilization
N2 - The hydrogen economy requires large-scale storage and transportation options like long-distance transmission pipelines. The applied materials (typically steels) must be carefully tested under different conditions (pressure, temperature, impact of impurities, etc.) for their suitability and service with hydrogen. In combination with mechanical load, as occurs in every gas network, hydrogen can induce degradation of the mechanical properties and promote finally resulting in embrittlement, i.e., the formation of cracks. The conventional testing procedures consist of autoclaves in which samples are strained under pressurized hydrogen. The test apparatus requires large amounts of hydrogen and thus a high level of safety and costs. In very specific cases, these tests might be replaced by simplified electrochemical charging. However, these test alternatives raise several questions regarding the equivalency of both testing scenarios. In the early 1980’s the idea of a so-called hollow tensile sample raised and was reinitiated 2021 in ISO TC 164 by T. Ogata (NIMS, Japan) and further developed (e.g. by Fraunhofer IWM, Germany). The idea was: the sample itself represents the autoclave instead of charging a sample from outside. For that reason, a hole is drilled through the sample and the inner surface is pressurized by hydrogen gas during the mechanical testing. Indeed, this represents the main advantage as no expensive pressure-resistant autoclave equipment for large H-volumes is necessary, which significantly reduces the safety-related issues and thus the high costs. In the following, we show recent activities at BAM Berlin on adaption of the hollow-specimen technique for slow strain rate testing (SSRT). The current research activities are focussed on macroscopic influences like the sample geometry, minimum necessary dimensions, and microscopic influences e.g., on the surface by the processing method (drill hole quality and geometric precision) as well as the gas pressure effect (mechanical deformation of surface in different media).
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 04.09.2023
KW - Hydrogen
KW - Hollow tensile specimen
KW - High-pressure
KW - Mechanical properties
KW - Testing
PY - 2023
AN - OPUS4-58220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beygi Nasrabadi, Hossein
T1 - Materials Mechanical Testing Ontology (MTO)
N2 - The materials mechanical testing ontology (MTO) was developed by collecting the mechanical testing vocabulary from ISO 23718 standard, as well as the standardized testing processes described for various mechanical testing of materials like tensile testing, Brinell hardness test, Vickers hardness test, stress relaxation test, and fatigue testing. Confirming the ISO/IEC 21838-2 standard, MTO utilizes the Basic Formal Ontology (BFO), Common Core Ontology (CCO), Industrial Ontologies Foundry (IOF), Quantities, Units, Dimensions, and data Types ontologies (QUDT), and Material Science and Engineering Ontology (MSEO) as the upper-level ontologies. Reusing these upper-level ontologies and materials testing standards not only makes MTO highly interoperable with other ontologies but also ensures its acceptance and applicability in the industry. MTO represents the mechanical testing entities in the 230 classes and four main parts: i) Mechanical testing experiments entities like tensile, hardness, creep, and fatigue tests as the subclasses of mseo:Experiment, ii) Mechanical testing quantity concepts such as toughness, elongation, and fatigue strength in the appropriate hierarchies of bfo:Disposition and bfo:Quality classes, iii) Mechanical testing artifacts like indenter as the subclasses of cco:Artifact, and iv) mechanical testing data like the stress-strain, S-N, or creep curves as the subclasses of cco:InformationContentEntity. MTO is publicly available via the KupferDigital GitLab repository.
T2 - FEMS EUROMAT 2023
CY - Frankfurt a. M., Germany
DA - 03.09.2023
KW - Mechanical testing
KW - Ontology
KW - Standard
PY - 2023
AN - OPUS4-58270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Miliūtė, Aistė
A1 - Bustamante, Joana
A1 - Mieller, Björn
A1 - Stawski, Tomasz
A1 - George, Janine
A1 - Knoop, F.
T1 - High-quality zirconium vanadate samples for negative thermal expansion (NTE) analysis
N2 - Zirconium vanadate (ZrV2O7) is a well-known negative thermal expansion (NTE) material which exhibits significant isotropic contraction over a broad temperature range (~150°C < T < 800°C). The linear thermal expansion coefficient of ZrV2O7 is −7.1×10-6 K-1. Therefore, it can be used to create composites with controllable expansion coefficients and prevent destruction by thermal shock.
Material characterization, leading to application, requires pure, homogenous samples of high crystallinity via a reliable synthesis route. While there is a selection of described syntheses in the literature, it still needs to be addressed which synthesis route leads to truly pure and homogenous samples. Here, we study the influence of the synthesis methods (solid-state, sol-gel, solvothermal) and their parameters on the sample's purity, crystallinity, and homogeneity. The reproducibility of results and data obtained with scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric analysis (DSC/TGA) were analyzed extensively. The sol-gel method proves superior to the solid-state method and produces higher-quality samples over varying parameters. Sample purity also plays an important role in NTE micro and macro-scale characterizations that explain the impact of porosity versus structural changes.
Moreover, we implement ab-initio-based vibrational computations with partially treated anharmonicity (quasi-harmonic approximation, temperature-dependent effective harmonic potentials) in combination with experimental methods to follow and rationalize the negative thermal expansion in this material, including the influence of the local structure disorder, microstructure, and defects. Khosrovani et al. and Korthuis et al., in a series of diffraction experiments, attributed the thermal contraction of ZrV2O7 to the transverse thermal motion of oxygen atoms in V-O-V linkages. In addition to previous explanations, we hypothesize that local disorder develops in ZrV2O7 crystals during heating.
We are working on the experimental ZrV2O7 development and discuss difficulties one might face in the process as well as high-quality sample significance in further investigation. The obtained samples are currently used in the ongoing research of structure analysis and the negative thermal expansion mechanism.
T2 - TDEP2023: Finite-temperature and anharmonic response properties of solids in theory and practice
CY - Linköping, Sweden
DA - 21.08.2023
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - TDEP
PY - 2023
AN - OPUS4-58135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Understanding and Machine Learning of Materials Properties with Quantum-Chemical Bonding Analysis
N2 - Bonds and local atomic environments are crucial descriptors for material properties. They have been used to create design rules for materials and are used as features in machine learning of material properties. This talk will show how our recently developed tools, that automatically perform quantum chemical bond analysis and enable the study of chemical bonds and local atomic environments, accelerate and improve the development of such heuristics and machine-learned models for materials properties.
T2 - Accelerate Conference 2023
CY - Toronto, Canada
DA - 22.08.2023
KW - Automation
KW - DFT
KW - Bonds
PY - 2023
AN - OPUS4-58131
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bustamante, Joana
A1 - Naik, Aakash
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - George, Janine
T1 - Thermodynamic and Thermoelectric Properties of the Canfieldite, (Ag8SnS6 ), in the Quasi-Harmonic Approximation
N2 - Argyrodite-type materials have lately sparked a lot of research interest due to their thermoelectric properties. One promising candidate is canfieldite (Ag8SnS6), which has a Pna21 orthorhombic crystal structure at room temperature (RT). Recently, Slade group found a new low-temperature (LT) phase transition of canfieldite at 120K. Therefore, we investigate structural, vibrational and thermodynamic properties of Ag8SnS6 at room- and low-temperature employing density-functional theory (DFT) and lattice dynamics computations. Thermal properties calculations were based on the quasi-harmonic approximation (QHA) as implemented in phonopy. We achieve good agreement with experiments. Lattice parameters were overestimated by 2%, and thermal properties such as the constant-pressure heat capacity Cp are very close to experimental measurements. Our simulations also reveal a possible new phase transition at around 312 K. Furthermore, we compared RT and LT Ag8SnS6 Grüneisen parameters with some argyrodites analogues, Ag8TS6 (T = Si, Ge, Ti and Sn), finding a relationship between the anharmonicity and low thermal conductivity.
T2 - TDEP Summer School 2023 (TDEP2023: Finite-temperature and anharmonic response properties of solids in theory and practice)
CY - Linköping, Sweden
DA - 20.08.2023
KW - Thermoelectric materials
KW - DFT
KW - QHA
KW - Grüneisen parameter
PY - 2023
AN - OPUS4-58147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Schartel, Bernhard
ED - Hu, Y.
ED - Wang, X.
T1 - Influence of the Size and Dispersion State of Two-Dimensional Nanomaterials on the Fire Safety of Polymers
N2 - Only the nano-scaled structure of the nanocomposite and the dispersion of nanoparticles within the polymer matrix harbor multifunctional potential including superior fire retardancy. Thus, this chapter focuses on the dispersion of nanoplates, based mainly on studies of layered silicates and graphene/graphene-related nanoplates. The nanostructure and properties of the nanocomposites are dependent mainly on thermodynamic and kinetic factors during preparation. Improving nano-dispersion often directly improves flame retardancy. Therefore, the modification of the nanoplates as well as the preparation of nanocomposites becomes very important to control this dispersion. The dispersion of nanoplates functions as a prerequisite for the formation of an efficient protective layer, changing the melt flow and dripping behavior, or the improvement of the char properties.
KW - Nanocomposite
KW - Flame retardancy
KW - 2D nanoparticle
KW - Exfoliation
KW - Dispersion
KW - Flammability
PY - 2023
SN - 978-1-032-35268-8
SN - 978-1-032-35502-3
SN - 978-1-003-32715-8
DO - https://doi.org/10.1201/9781003327158-2
SP - 23
EP - 58
PB - CRC Press
CY - Boca Raton
AN - OPUS4-58290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holzer, Marco
T1 - A new model for predicting fracture surface energies in oxide glasses - How cleavage planes help us understand the intrinsic fracture toughness of oxide glasses
N2 - The search for strong and tough oxide glasses is important for making safer, more environmentally friendly, thinner glass products. However, this task remains generally difficult due to the material’s inherent brittleness. In search for tougher glasses, fracture toughness (KIC) prediction models are helpful tools to screen for promising candidates.
In this work, a novel model to predict KIC via the fracture surface energy, γ, is presented. Our approach uses readily available crystallographic structure data of the glass’s isochemical crystal and tabled diatomic chemical bond energies, D0. The method assumes that γ of a glass equals the fracture surface energy of the most likely cleavage plane of the crystal. Calculated values were not only in excellent agreement with those calculated with a former well-working model, but also demonstrates a remarkable equivalence between crystal cleavage planes and glass fracture surfaces.
Finally, the effectiveness of fracture toughness enhancement by chemical substitution is discussed based on our results and alternative toughening strategies will be suggested.
T2 - Deparment Seminar Materials Engineering
CY - Berlin, Germany
DA - 15.06.2023
KW - Fracture Toughness
KW - Oxide Glasses
KW - Fracture Mechanics
KW - Silicate Glasses
KW - Phase Separation
PY - 2023
AN - OPUS4-58419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holzer, Marco
T1 - Fracture surface energy of glasses obtained from crystalline structure and bond energy data
N2 - The search for strong and tough oxide glasses is important for making safer, environment-friendlier, thinner glasses. As fracture toughness experiments in brittle materials are complicated and time-consuming , modelling glass fracture surface energy, G, and fracture toughness, KIc, is of interest for screening promising candidates. Inspired by Rouxel´s idea of preferred crack growth along cutting weakest bonds within a glass structure and a study by Tielemann et al. , which indicates a correlation between crystal fracture surface and glass-crys¬tal interfacial energies, we present a new approach for predicting G. Combining both ideas, we used diatomic bond energies and readily available crystallographic structure data for estimating G. The proposed method assumes that G of the glass equals the surface fracture energy of the cleavage plane in its respective isochemical crystal. We calculated G- values for more than 25 iso-chemical silicate systems and compared them to calculated values from Rouxel’s widely used procedure, which is well working and based on glass densities and chemical bond energies. Not only does our model yields good agreement with [3], but it also enables an estimation for glasses with unknown density and can therefore contribute to broaden the data basis for glass property modelling tools. Most interestingly, however, this agreement indicates an interesting similarity between cleavage planes in a crystal and its corresponding glass state in terms of fracture processes.
T2 - DGG-USTV Joint annual meeting 2023
CY - Orleans, France
DA - 22.05.2023
KW - Fracture Toughness
KW - Oxide Glasses
KW - Surface Energy
KW - Silicate Glasses
PY - 2023
AN - OPUS4-58416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ulbricht, Alexander
T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion
N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed.
T2 - Annual International Solid Freeform Fabrication Symposium
CY - Austin, TX, USA
DA - 14.08.2023
KW - AISI 316L
KW - Additive Manufacturing
KW - Computed Tomography
KW - Creep
KW - Laser Powder Bed Fusion
KW - Microstructure
KW - PBF-LB/M/316L
PY - 2023
AN - OPUS4-58285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Olbricht, Jürgen
T1 - Einfluss von Haltezeiten auf die TMF-Lebensdauer von P92 bei mittleren und geringen Dehnungsamplituden
N2 - Results of an extended TMF test program on grade P92 steel in the temperature range of 620 ◦C–300 ◦C, comprising in-phase (IP) and out-of-phase (OP) tests, partly performed with symmetric dwells at Tmax/Tmin, are presented. In contrast to previous studies, the low-strain regime is also illuminated, which approaches flexible operation in a power plant with start/stop cycles. At all strain amplitudes, the material performance is characterized by continuous cyclic softening, which is retarded in tests at lower strains but reaches similar magnitudes in the course of testing. In the investigated temperature range, the phase angle does not affect fatigue life in continuous experiments, whereas the IP condition is more detrimental in tests with dwells. Fractographic analyses indicate creep-dominated and fatigue-dominated damage for IP and OP, respectively. Analyses of the (micro)hardness distribution in the tested specimens suggest an enhanced microstructural softening in tests with dwell times for the low- but not for the high-strain regime. To rationalize the obtained fatigue data, the fracturemechanics-based DTMF concept, which was developed for TMF life assessment of ductile alloys, was applied. It is found that the DTMF parameter correlates well with the measured fatigue lives, suggesting that subcritical growth of cracks (with sizes from a few microns to a few millimeters) governs failure in the investigated range of strain amplitudes.
T2 - DVM-Arbeitskreis Bauteilverhalten bei thermomechanischer Ermüdung - Workshop 2023
CY - Berlin, Germany
DA - 20.09.2023
KW - 9–12%Cr steel
KW - Thermomechanical fatigue
KW - Symmetric dwell periods
KW - Parametric modeling
PY - 2023
AN - OPUS4-58431
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bustamante Pineda, Joana Cecibel
A1 - George, Janine
T1 - Sulfide-Argyrodites: Thermal properties within the QHA
N2 - Argyrodite-type materials have lately sparked a lot of research interest due to their thermoelectric properties. One promising candidate is canfieldite (Ag8SnS6), which has a Pna21 orthorhombic crystal structure at room temperature (RT). Recently, experimentalists have found a new low-temperature (LT) phase transition of canfieldite at 120K. Therefore, we investigate structural, vibrational and thermodynamic properties of Ag8SnS6 at room- and low-temperature employing density-functional theory (DFT) and lattice dynamics computations. Thermal properties calculations were based on the quasi-harmonic approximation (QHA) as implemented in phonopy. We achieve good agreement with experiments. Lattice parameters were overestimated by 2%, and thermal properties such as the constant-pressure heat capacity Cp are very close to experimental measurements. Our simulations also reveal a possible new phase transition at around 312 K. Furthermore, we compared RT and LT Ag8SnS6 Grüneisen parameters with some argyrodites analogues, Ag8TQ6 (T = Si, Ge, Ti and Sn; Q = S, Se), finding a relationship between the anharmonicity and low thermal conductivity.
T2 - SALSA Make and Measure Conference
CY - Berlin, Germany
DA - 13.09.2023
KW - Thermoelectric materials
KW - DFT
KW - QHA
KW - Grüneisen parameter
PY - 2023
AN - OPUS4-58368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ertural, Christina
T1 - Automation of machine learning driven interatomic potential generation for predicting vibrational properties
N2 - Knowing phonon properties is beneficial for predicting low thermal conductivity thermoelectric materials. Employing DFT consumes lots of computational resources. Using ML-driven interatomic potentials (MLIP, e.g., GAP) opens up a faster route, but most potentials are specifically tailored to a certain compound. We aim to generalize the MLIP generation in a Python code-based workflow, combining automatic DFT runs with automated GAP fits. Automation enables easier tests, benchmarks, and validation.
T2 - SALSA Make and Measure Conference: Interfaces
CY - Berlin, Germany
DA - 13.09.2023
KW - Interatomic potentials
KW - Machine learning
KW - Phonons
KW - Thermoelectrics
KW - Automated workflows
PY - 2023
AN - OPUS4-58374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
A1 - Hanke, Thomas
A1 - Eisenbart, Miriam
T1 - Mechanical testing ontology (MTO)
N2 - The materials mechanical testing ontology (MTO) was developed by collecting the mechanical testing vocabulary from ISO 23718 standard, as well as the standardized testing processes described for various mechanical testing of materials like tensile testing, Brinell hardness test, Vickers hardness test, stress relaxation test, and fatigue testing.
Versions info:
V2 developed using BFO+CCO top-level ontologies.
V3 developed using PROVO+PMDco top-level ontologies.
V4 developed using BFO+IOF top-level ontologies.
Repositories:
GitLab: https://gitlab.com/kupferdigital/ontologies/mechanical-testing-ontology
GitHub: https://github.com/HosseinBeygiNasrabadi/Mechanical-Testing-Ontology
MatPortal: https://matportal.org/ontologies/MTO
IndustryPortal: https://industryportal.enit.fr/ontologies/MTO
KW - Ontology
KW - Mechanical testing
KW - FAIR data
PY - 2023
UR - https://gitlab.com/kupferdigital/ontologies/mechanical-testing-ontology/
PB - GitLab
CY - San Francisco, CA, USA
AN - OPUS4-58271
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radners, Jan
A1 - Han, Ying
A1 - von Hartrott, Philipp
A1 - Skrotzki, Birgit
T1 - Aluminum High Temperature Fatigue
N2 - The high operating temperatures of radial compressor wheels in exhaust gas turbochargers lead to a change in the original microstructure of the heat-resistant aluminum alloy EN AW-2618A (overaging). This is caused by thermal loads that are close to the age hardening temperature and can even exceed it for a short time. The aging mechanisms have been investigated together with low cycle fatigue (LCF), thermomechanical fatigue (TMF) and creep up to max. 190 °C in previous research projects. The be-havior of the alloy under high cycle fatigue (HCF) and the influence of load spectra have hardly been investigated. Since the operating temperatures of centrifugal compressors are expected to increase in the future, this research project investigated the HCF behavior at 230 °C, a test temperature significantly higher than the age hardening temperature. The objectives of the project were to establish a suitable experimental database, to understand the relevant microstructural processes, and to further develop and adapt suitable models and evaluation methods.
In addition to a basic characterization of the HCF behavior in the initial condition T61, the experimental investigation program included targeted mechanical tests to isolate the influencing factors of mean stress (𝑅=−1, 𝑅=0.1), material overaging (T61, 10 h/230 °C, 1000 h/230 °C), test temperature (20 °C, 230 °C), test frequency (0.2 Hz, 20 Hz) as well as variable amplitudes. On this basis, the models and evaluation methods developed in the previous projects were adapted and further developed to reflect thermal and mechanical loads in the lifetime assessment.
T2 - The FVV Transfer + Networking Event (Herbst 2023)
CY - Würzburg, Germany
DA - 04.10.2023
KW - Aluminum alloys
KW - Fatigue
KW - EN AW-2618A
PY - 2023
SP - 1
EP - 30
AN - OPUS4-58562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Rethmeier, Michael
T1 - Challenges in dynamic heat source modeling in high-power laser beam welding
N2 - The amount of absorbed energy in the keyhole as well as its spatial and temporal distribution is essential to model the laser beam welding process. The recoil pressure, which develops because of the evaporation process induced by the absorbed laser energy at the keyhole wall, is a key determining factor for the macroscopic flow of the molten metal in the weld pool during high-power laser beam welding. Consequently, a realistic implementation of the effect of the laser radiation on the weld metal is crucial to obtain reliable and accurate simulation results.
In this paper, we discuss manyfold different improvements on the laser-material interaction, namely the ray-tracing method, in the numerical simulation of the laser beam welding process. The first improvement relates to locating the exact reflection points in the ray tracing method using a so-called cosine condition in the determination algorithm for the intersection of the reflected rays and the keyhole surface. A second correction refers to the numerical treatment of the Gaussian distribution of the laser beam, whose beam width is defined by a decay of the laser intensity by a factor of 1/e2 thus ignoring around 14 % of the total laser beam energy. In a third step, the changes in the laser radiation distribution in the vertical direction were adapted by using different approximations for the converging and the diverging regions of the laser beam thus mimicking the beam caustic. Finally, a virtual mesh refinement was adopted in the ray tracing routine. The obtained numerical results were validated with experimental measurements.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, USA
DA - 16.10.2023
KW - Laser beam welding
KW - Laser energy distribution
KW - Ray tracing
KW - Numerical modeling
PY - 2023
SP - 1
EP - 10
AN - OPUS4-58475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Srinivasan, Krishnanand
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser Metal Deposition of Rene 80 – Microstructure and Solidification Behaviour Modelling
N2 - New developments in nickel-based superalloys and production methods, such as the use of additive manufacturing (AM), can result in innovative designs for turbines. It is crucial to understand how the material behaves during the AM process to advance industrial use of these techniques. An analytical model based on reaction-diffusion formalism is developed to better explain the solidification behavior of the material during laser metal deposition (LMD). The well-known Scheil-Gulliver theory has some drawbacks, such as the assumption of equilibrium at the solid-liquid interface, which is addressed by this method. The solidified fractions under the Scheil model and the pure equilibrium model are calculated using CALPHAD simulations. Differential scanning calorimeter is used to measure the heat flow during the solid-liquid phase transformation, the result of which is further converted to solidified fractions. The analytical model is compared with all the other models for validation.
T2 - Lasers in Manufacturing Conference 2023
CY - Munich, Germany
DA - 26.06.2023
KW - Additive manufacturing
KW - Laser metal deposition
KW - Solidification behaviour
KW - Analytical model
KW - Nickel-based superalloy
PY - 2023
SP - 1
EP - 10
AN - OPUS4-58612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mente, Tobias
T1 - Schadensprävention durch Werkstoff- und Komponentenprüfung unter Druckwasserstoff
N2 - Historischer Schadensfall Wasserstoff-Gasflaschen von A. Martens aus dem Jahr 1894 .Prüfung von Hohlzugproben unter Druckwasserstoff - Herausforderungen und Umsetzung.
T2 - Forum Schadenverhütung der Arbeitsgemeinschaft Berlin Brandenburg (AGS) in Kooperation mit der AGBB Berlin e.V.
CY - Berlin, Germany
DA - 12.10.2023
KW - Hohlzugprobe
KW - Wasserstoff
PY - 2023
AN - OPUS4-58623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Radners, Jan
T1 - Aluminum High Temperature Fatigue
N2 - The high operating temperatures of radial compressor wheels in exhaust gas turbochargers lead to abchange in the original microstructure of the heat-resistant aluminum alloy EN AW-2618A (overaging). This is caused by thermal loads that are close to the age hardening temperature and can even exceed it for a short time. The aging mechanisms have been investigated together with low cycle fatigue (LCF), thermomechanical fatigue (TMF) and creep up to max. 190 °C in previous research projects. The behavior of the alloy under high cycle fatigue (HCF) and the influence of load spectra have hardly been investigated. Since the operating temperatures of centrifugal compressors are expected to increase in the future, this research project investigated the HCF behavior at 230 °C, a test temperature significantly higher than the age hardening temperature. The objectives of the project were to establish a suitable experimental database, to understand the relevant microstructural processes, and to further develop and adapt suitable models and evaluation methods. In addition to a basic characterization of the HCF behavior in the initial condition T61, the experimental investigation program included targeted mechanical tests to isolate the influencing factors of mean stress (𝑅 = −1, 𝑅 = 0.1), material overaging (T61, 10 h/230 °C, 1000 h/230 °C), test temperature (20 °C, 230 °C), test frequency (0.2 Hz, 20 Hz) as well as variable amplitudes. On this basis, the models and evaluation methods developed in the previous projects were adapted and further developed to reflect thermal and mechanical loads in the lifetime assessment.
T2 - The FVV Transfer + Networking Event (Herbst 2023)
CY - Würzburg, Germany
DA - 04.10.2023
KW - Aluminum alloys
KW - Fatigue
KW - EN AW-2618A
PY - 2023
AN - OPUS4-58537
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Influence of shielding gas on filler wire mixing at laser hybrid welding of thick high strength steels
N2 - The laser hybrid welding process offers many advantages during welding oft hick-walled steels, such as the increased penetration depth and, thus, reduced number of layers, reduced heat input and decreased distortion compared to arc-based welding processes. Especially, when welding high-strength steels (HSS), the reduced heat input plays an essential role. However, a major challenge when laser hybrid welding of thick-walled steels is the limited filler wire mixing over the entire seam thickness, which can lead to changed mechanical properties over the depth. To overcome this issue, the add of oxygen into the shielding gas and its influence on the filler wire mixing and finally to the mechanical properties were investigated within this work. Therefore, 20 mm thick S690QL steels were laser hybrid welded in a single-pass. A contactless electromagnetic backing was used to avoid sagging. The admixture of oxygen was performed by a gas mixer, where the oxygen content was varied between 0 % and 7.2 %. The experiments were also accompanied by laser beam welding tests in steel/glass configuration, where the melt pool geometry as well as the melt flow characteristics were captured by a high-speed camera. It can be concluded, that adding of 2 % to 4 % oxygen into the shielding gas had a positive effect on the filler wire mixing, were up to a depth of 18 mm elements of the filler wire could be observed.
T2 - 19th Nordic Laser Material Processing Conference
CY - Turku, Finland
DA - 22.08.2023
KW - Laser hybrid welding
KW - Electromagnetic backing
KW - Shielding gas
KW - Charpy impact toughness
KW - Thick-plate welding
KW - Filler wire mixing
PY - 2023
AN - OPUS4-58615
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Putra, Stephen Nugraha
A1 - Rethmeier, Michael
T1 - Experimental and numerical study on grain refinement in electromagnetic assisted laser beam welding of 5754 al alloy
N2 - Through experimental observation and auxiliary numerical simulation, this investigation studies the different types of grain refinement of 5754 aluminum alloy laser beam welding by applying a transverse oscillating magnetic field. Scanning electron microscope results have proved that the application of a magnetic field can reduce the average crystal branch width and increase its number. The interaction between the induced eddy current generated by the Seebeck effect and the applied external magnetic field produces a Lorentz force, which is important for the increase in the number of crystal branches. Based on the theory of dendrite fragmentation and the magnetic field-induced branches increment, the grain size reduction caused by the magnetic field is studied. Furthermore, the effects of the magnetic field are ana lyzed by combining a phase field method model and simulations of nucleation and grain growth. The grain distribution and average grain size after welding verify the reliability of the model. In addition, the introduction of a magnetic field can increase the number of periodic three-dimensional solidification patterns. In the intersection of two periods of solidification patterns, the metal can be re-melted and then re-solidified, which prevents the grains, that have been solidified and formed previously, from further growth and generates some small cel lular grains in the new fusion line. The magnetic field increases the building frequency of these solidification structures and thus promotes this kind of grain refinement.
T2 - ICALEO 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Laser beam welding
KW - Magnetic field
KW - Crystal branch development
KW - Grain refinement
KW - Periodic solidification pattern
PY - 2023
AN - OPUS4-58493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Böllinghaus, Thomas
A1 - Rhode, Michael
A1 - Falkenreck, T.
ED - Grote, K.-H.
ED - Hefazi, H.
T1 - 6. Corrosion and Corrosion Resistance
N2 - The chapter starts with a brief introduction about corrosion, which is defined as the interdependency between a metal, a corrosive environment, and the respective component design. The second section introduces the most important forms of aqueous electrochemical corrosion (uniform corrosion, galvanic corrosion, selective and intergranular corrosion, and finally pitting and crevice corrosion in the case of passive layer forming metals). In addition, electrochemical corrosion under applied mechanical load is introduced (stress corrosion cracking, hydrogen-assisted cracking, corrosion fatigue), as well as special forms of corrosion (erosion, fretting, and microbiologically induced corrosion). The third section of this chapter introduces (mostly dry) chemical corrosion and high-temperature corrosion (oxidation, carburization, high-temperature hydrogen attack, sulfurization, nitriding, halogenation). As in the case of electrochemical corrosion, chemical corrosion can also be superimposed by mechanical loads. Finally, general facts on the testing of corrosion are introduced.
KW - Corrosion
KW - Corrosion testing
KW - Handbook
KW - Electrochemical corrosion
KW - Chemical corrosion
PY - 2021
SN - 978-3-030-47035-7
DO - https://doi.org/10.1007/978-3-030-47035-7_6
VL - 2021
SP - 185
EP - 213
PB - Springer Nature Switzerland AG
CY - Cham (CH)
ET - 2nd Edition
AN - OPUS4-52423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schartel, Bernhard
T1 - Weathering resistance of halogen-free flame retardancy in thermoplastics
N2 - Weathering resistance of halogen-free flame retardancy in thermoplastics
- Durability of fire retardancy
- Impact of different exposure condition
- Degradation with respect to different fire tests
T2 - 17th SKZ Conference on Trends in Fire Safety and Innovative Flame Retardants for Plastics
CY - Online Meeting
DA - 18.05.2021
KW - Durability
KW - Flame retardant
KW - Aluminum hydroxide (ATH)
KW - Weathering
KW - Cable
KW - TPU
KW - EVA
KW - Polyamide 6.6
KW - Aluminium diethylphosphinate
PY - 2021
AN - OPUS4-52680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Experimentelle Ermittlung zyklischer R-Kurven in additiv gefertigtem AISI 316L Stahl
N2 - Diese Untersuchung beschäftigt sich mit der Charakterisierung von Kurzrisswachstum in mittels Laser-Pulverbett-Verschmelzen (LPBF - Laser Powder Bed Fusion) hergestelltem rostfreien austenitischen Stahl. Spezifischer wird die Ermittlung zyklischer R-Kurven untersucht. Diese beschreiben den Aufbau des Widerstands gegen Ermüdungsrisswachstum - d.h. des Schwellenwertes - aufgrund von Rissschließeffekten bei physikalisch kurzen Rissen. Mit Hilfe der zyklischen R-Kurven kann die Fähigkeit eines Bauteils, physikalisch kurze Risse zu arretieren, charakterisiert werden. Wir verfügen damit über eine Schnittstelle zwischen klassischer Ermüdung und Bruchmechanik. Das ist gerade auch für additiv gefertigte (AM – Additive Manufacturing) Materialien von Interesse. Diese weisen prozessintrinsische Defekte auf, die als Initiierungsstellen kurzer Ermüdungsrisse agieren. Im Rahmen der experimentellen Untersuchungen wurden zyklische R-Kurven für konventionellen und LPBF AISI-316L-Stahl ermittelt. Insbesondere wurde der Einfluss verschiedener Wärmebehandlungen (WB1: 450°C, WB2: 800°C und WB3: 900°C) auf das Wachstumsverhalten physikalisch kurzer Risse im LPBF-Material untersucht. Aufgrund hoher Eigenspannungen war die Ermittlung des Kurzrisswachstumsverhaltens bei WB1 nicht möglich. Für WB2 und WB3 ergaben sich sehr unterschiedliche zyklische R-Kurven. Untersuchungen der Eigenspannungen, der Bruchfläche (insbesondere der Rauheit) und der Mikrostruktur sollen die Ursachen für das unterschiedliche Verhalten erklären. Die Ergebnisse werden mit den Verhältnissen in konventionellem Material verglichen.
T2 - Tagung des Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 18.02.2021
KW - Additive Manufacturing
KW - Zyklische R-Kurve
KW - Ermüdungsriss
KW - L-PBF
KW - 316L
PY - 2021
AN - OPUS4-52250
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Vergleichende Untersuchungen zum intrinsischen Schwellenwert der da/dN-∆K Kurve
N2 - Für die Bestimmung der Restlebensdauer zyklisch beanspruchter Bauteile kommt dem Schwellenwert für Ermüdungsrissausbreitung, Δ𝐾𝑡ℎ, und dem sich anschließenden Schwellenwertbereich der 𝑑𝑎𝑑𝑁⁄−Δ𝐾-Kurve große Bedeutung zu. Dem stehen Unsicherheiten bei der Bestimmung und Analyse gegenüber. Der Aufsatz befasst sich mit der Ermittlung des sogenannten intrinsischen Schwellenwerts, der als robuster Eingangsparameter für eine „rissschließfreie“ Analyse der Restlebensdauer von entscheidender Bedeutung ist.
T2 - DVM-Arbeitskreis „Bruchmechanik und Bauteilsicherheit“ 2021
CY - Online meeting
DA - 18.02.2021
KW - Schadenstolerante Bauteilauslegung
KW - Restlebensdauer
KW - Intrinsischer Schwellenwert gegen Ermüdungsrissausbreitung
PY - 2021
AN - OPUS4-52263
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Short fatigue crack propagation in additively manufactured stainless steel 316L
N2 - Fracture mechanics is a key to fatigue assessment in AM metal components. Short fatigue cracks are initiated at defects and pronounced surface roughness intrinsic to AM. The subsequent crack-propagation is strongly influenced by microstructural interactions and the build-up of crack-closure. The aim of the present study is to give an insight into short-crack propagation in AM-metals. Fatigue crack propagation resistance curves were determined experimentally for AISI 316L manufactured by Laser Powder Bed Fusion (L-PBF) which was heat treated at three different temperatures. Differences in the build-up of the fatigue-crack propagation threshold in between the L-PBF specimens and compared to wrought material are due to the residual stress states, a pronounced roughness of the crack-faces in the L-PBF specimens and phase transformation in the vicinity of the crack-tip, resulting in increased crack-closure. This, together with crack-branching found along the crack path, enhances the resistance to the propagation of fatigue cracks.
T2 - In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys
CY - Online meeting
DA - 19.04.2021
KW - AM
KW - Cyclic R-Curve
KW - Fatigue Crack Propagation
PY - 2021
AN - OPUS4-52587
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
T1 - Unraveling thermal radiation by multispectral thermography: Real temperatures in LMD
N2 - Additive manufacturing of metals offers the opportunity to build parts with a high degree of complexity without additional costs, opening a new space for design optimization. However, the processes are highly complex and due to the rapid thermal cycles involved, high internal stresses and peculiar microstructures occur, which influence the parts mechanical properties. To systematically examine the formation of internal stresses and the microstructure, in-process spatially resolved measurements of the part temperature are needed. If the emissivity of the inspected part is known, its thermodynamic temperature can be reconstructed by a suited radiometric model. However, in additive manufacturing of metals, the emissivity of the part surface is strongly inhomogeneous and rapidly changing due to variations of, e.g., the degree of oxidation, the material state and temperature. Thus, here, the applicability of thermography in the determination of thermodynamic temperatures is limited. However, measuring the process thermal radiation at different wavelengths simultaneously enables one to separate temperature and emissivity spatially resolved to obtain further insight into the process. Here, we present results of an initial study using multispectral thermography to obtain real temperatures and emissivities in the powderfree LMD process.
T2 - 2nd Workshop on In-situ Monitoring and Microstructure Development in Additive Manufactured Alloys
CY - Online meeting
DA - 19.04.2021
KW - Additive Manufacturing
KW - Process monitoring
KW - Multispectral thermography
KW - Laser metal deposition
KW - TES
KW - LMD
KW - Temperature emissivity separation
PY - 2021
AN - OPUS4-52514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abel, Andreas
T1 - Microstructural evolution of Fe-26Al-4Mo-0.5Ti-1B with varying wall thicknesses
N2 - With an increasing demand in more efficient fuel consumption to reduce CO2 emissions, weight reductions in high-temperature materials at affordable costs gain increasing attention. One potential candidate is the intermetallic material class of iron aluminides, combining the advantages in mass savings, high temperature performance and recyclability of resources. The alloy Fe-26Al-4Mo-0.5Ti-1B was selected to study the microstructural features evolving from two casting processes, five wall thicknesses and three final conditions. Conclusions are drawn upon the correlations of processing variables, grain sizes and hardness.
T2 - DGM Fachausschuss "Intermetallische Phasen"
CY - Online meeting
DA - 09.02.2021
KW - Intermetallics
KW - Iron aluminides
KW - Fe-Al alloys
KW - Wall thickness
KW - Microstructure
PY - 2021
AN - OPUS4-52288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lee, P.-W.
A1 - Kaynak, T.
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Schalley, C.
T1 - Effect of Perfluorinated Side-Chain Length on the Morphology, Hydrophobicity, and Stability of Xerogel Coatings
N2 - Superhydrophobic surfaces can be quickly formed with supramolecular materials. Incorporating low-molecular-weight gelators (LMWGs) with perfluorinated chains generates xerogel coatings with low surface energies and high roughness. Here, we examine and compare the properties of the xerogel coatings formed with eight different LMWGs. These LMWGs all have a trans-1,2-diamidocyclohexane core and two perfluorinated ponytails, whose lengths vary from three to ten carbon atoms (CF3 to CF10). Investigation of the xerogels aims to provide in-depth information on the chain length effect. LMWGs with a higher degree of fluorination (CF7 to CF10) form superhydrophobic xerogel coatings with very low surface energies. Scanning electron microscopy images of the coatings show that the aggregates of CF5 and CF7 are fibrous, while the others are crystal-like. Aggregates of CF10 are particularly small and further assemble into a porous structure on the micrometer scale. To test their stabilities, the xerogel coatings were flushed multiple times with a standardized water flush test. The removal of material from the surface in these flushes was monitored by a combination of the water contact angle, contact angle hysteresis, and coating thickness measurements. A new method based on image processing techniques was developed to reliably determine the change of the coating thickness. The CF7, CF9, and CF10 surfaces show consistent hydrophobicity and coating durability after repetitive flushing tests. The length of the perfluorinated side chains thus has a significant effect on the morphology of the deposited xerogel coatings, their roughness, and, in consequence, their hydrophobicity and mechanical durability.
KW - Coating materials
KW - Amorphous materials
KW - Hydrophobicity
KW - Materials Stability
PY - 2021
DO - https://doi.org/10.1021/acs.langmuir.1c02341
SN - 1520-5827
VL - 37
IS - 49
SP - 14390
EP - 14397
PB - ACS Publications
AN - OPUS4-54071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
A1 - Karkhin, V.
A1 - Khomich, P.
T1 - Modeling of hydrodynamic and thermal processes at laser welding with through penetration
N2 - A mathematical model for physical processes in fusion welding has been developed. It is based on the equivalent heat source concept and consists of two parts: thermo-hydrodynamics of the weld pool and heat conduction in the weldment outside the pool. In thermo-hydrodynamic problem, temperature – dependent material properties, keyhole shape, thermo-capillary and natural convection, phase transformations and other physical phenomena are taken into consideration.
Solution of the thermo-hydrodynamic problem by the finite element method is demonstrated with keyhole laser beam welding of a 15 mm thick steel plate. Thermo-capillary convection is primarily responsible for the intricate convex-concave melt pool shape and pool enlargement near the plate surfaces. The calculated and experimental molten pool dimensions are in close agreement.
KW - Laser welding
KW - Weld pool modeling
KW - Heat conduction
KW - Greens function method
PY - 2021
DO - https://doi.org/10.1080/09507116.2021.1989209
SP - 1
EP - 12
PB - Taylor & Francis Group
AN - OPUS4-54022
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Verbesserung der Vorhersagegüte von künstlichen neuronalen Netzen zum Widerstandspunktschweißen durch Auswertung des dynamischen Widerstands
N2 - Das Widerstandspunktschweißen ist ein etabliertes Fügeverfahren in der Automobilindustrie. Es wird vor allem bei der Herstellung sicherheitsrelevanter Bauteile, zum Beispiel der Karosserie, eingesetzt. Daher ist eine kontinuierliche Prozessüberwachung unerlässlich, um die hohen Qualitätsanforderungen zu erfüllen. Künstliche neuronale Netzalgorithmen können zur Auswertung der Prozessparameter und -signale eingesetzt werden, um die individuelle Schweißpunktqualität zu gewährleisten. Die Vorhersagegenauigkeit solcher Algorithmen hängt von dem zur Verfügung gestellten Trainingsdatensatz ab. In diesem Beitrag wird untersucht, inwieweit die Vorhersagegüte eines künstlichen neuronalen Netzes durch Auswertung einer Prozessgröße, dem dynamischen Widerstand, verbessert werden kann.
KW - Künstliche Intelligenz
KW - Qualität
KW - Neuronales Netz
KW - Widerstandspunktschweißen
PY - 2021
SP - 785
EP - 789
AN - OPUS4-53976
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, V.
A1 - Marko, A.
A1 - Kruse, T.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Analysis and recycling of bronze grinding waste to produce maritime components using directed energy deposition
N2 - Additive manufacturing promises a high potential for the maritime sector. Directed Energy Deposition (DED) in particular offers the opportunity to produce large-volume maritime components like propeller hubs or blades without the need of a costly casting process. The post processing of such components usually generates a large amount of aluminum bronze grinding waste. The aim of the presented project is to develop a sustainable circular AM process chain for maritime components by recycling aluminum bronze grinding waste to be used as raw material to manufacture ship Propellers with a laser-powder DED process. In the present paper, grinding waste is investigated using a dynamic image Analysis system and compared to commercial DED powder. To be able to compare the material quality and to verify DED process parameters, semi-academic sample geometries are manufactured.
T2 - LiM 2021
CY - Munich, Germany
DA - 21.06.2021
KW - Additive Manufacturing
KW - Maritime Components
KW - Powder Analysis
KW - Recycling
KW - Directed Energy Deposition
PY - 2021
SP - 1
EP - 9
AN - OPUS4-54067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Deland, Eric
T1 - Environmental conditions affect the corrosion product composition of Methanogen induced microbiologically influenced corrosion (Mi-MIC)
N2 - Corrosion is a very expensive and serious problem in the different industry sectors, eg. Petroleum-, On- and off-shore, infrastructure. It is estimated that 20% of all corrosion damage is caused by microorganisms or microbiologically influenced corrosion (MIC). Several microorganisms are known to cause corrosion, including sulfate-reducing bacteria, nitrate-reducing bacteria, methanogens etc. For several years, methanogens were regarded as a mild corroder (~0.065 mm/yr), largely due to a lack of detailed investigation on the corrosion mechanism under real-environment simulated conditions. Resulting in the common belief that siderite, a non-conductive compound, is the sole corrosion product (CP) of methanogen-induced MIC (Mi-MIC).
To simulate natural environmental conditions, we developed and introduced the multiport flow column system (MFC), a multi-sectional corrosion flow-cell. Using the MFC, we obtained ten times higher corrosion rates than previously reported. With a combination of several analytical techniques, such as ToF-SIMS, SEM-EDS and FIB-SEM, we found strong indication that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contained phosphorus, oxygen, magnesium, calcium and iron. The differences in the CP between static and dynamic environments demonstrated the impact of testing procedures on the corrosive potential of methanogens. To further verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate) on Mi-MIC.
Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors.
T2 - ISMOS-8
CY - Online meeting
DA - 08.06.2021
KW - Methanogen-induced microbiologically influenced corrosion
KW - Carbon steel
KW - ToF-SIMS
KW - Modelling studies
PY - 2021
AN - OPUS4-54041
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Deland, Eric
T1 - Environmental conditions impact the corrosion layer composition of Methanogen induced microbiologically influenced corrosion (Mi-MIC)
N2 - Microbiologically influenced corrosion (MIC) is a now well-known challenge and affects industry, society and infrastructure. For a long time, the impact of methanogen-induced MIC (Mi-MIC) was underestimated. This was mainly due to the rather low published corrosion rates and the presumed corrosion product siderite, which is not electrically conductive. In our laboratory, we were able to show that this trivialization or underestimation of Mi-MIC was due to the nature of the testing. The static systems used so far do not provide environmentally relevant information about the corrosion rate and the corrosion product, especially for methanogens
To further illustrate the importance of the environment on the MIC process, we established a multiport flow column (MFC), to simulate the natural environment. With this method, and in contrast to published results using the static conditions, we obtained ten times higher corrosion rates. We analyzed the corrosion products with a combination of techniques, like ToF-SIMS, SEM-EDS and FIB-SEM, and found strong evidence that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron and lacked on carbon-related species. It is hypothesized that methanogens may have influenced the nucleation process of siderite, converting bicarbonate into carbon dioxide for methanogenesis. This results in increased localized corrosion and reduced siderite formation. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate etc.) on Mi-MIC and the subsequent impacts on corrosion rates and the corrosion products.
Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors.
T2 - Eurocorr 2021
CY - Online meeting
DA - 20.09.2021
KW - Methanogen-induced microbiologically influenced corrosion
KW - Carbon steel
KW - SEM-EDS
KW - Modelling studies
PY - 2021
AN - OPUS4-54043
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, M.
A1 - El-Sari, B.
A1 - Rethmeier, Michael
A1 - Finus, F.
T1 - Schweißen unter Zug – LME-Eingangsprüfung für die Autoindustrie
N2 - Der Trend zum Leichtbau und die Transformation zur E-Mobilität in der
Automobilindustrie befeuern die Entwicklung neuer hochfester Stähle für den Karosseriebau. Derartige Werkstoffe sind beim Widerstandspunktschweißen besonders rissanfällig (LME). Das Schweißen unter Zug stellt eine effektive Methode um die LME-Anfälligkeit unterschiedlicher Werkstoffe qualitativ zu bestimmen.
KW - Automobilindustrie
KW - Widerstandspunktschweißen
KW - Liquid Metal Embrittlement
KW - Zinkbeschichtung
KW - Hochfester Stahl
PY - 2021
IS - 6
SP - 54
EP - 55
AN - OPUS4-54057
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Roveda, Ilaria
T1 - Investigation of residual stresses and microstructure effects on the fatigue behaviour of a L-PBF AlSi10Mg alloy
N2 - Al-Si alloys produced by Laser Powder Bed Fusion (L-PBF) techniques allow the fabrication of lightweight free-shape components. Due to the high cooling rates occurring during the building process, L-PBF AlSi10Mg alloys exhibit an ultra-fine microstructure that leads to superior mechanical properties in the as-built condition compared to conventional cast Al-Si materials. Nevertheless, L-PBF processing induces high thermal gradients, leading to deleterious residual stress. In order to relax detrimental residual stress and to increase the ductility, post-processing stress relief treatments are performed. The objective of the contribution is to investigate, under different heat treatment condition, the evolution of microstructure and residual stresses in view of optimizing the fatigue performance of the alloy. To this purpose various heat treatments in a range of temperatures between 265°C and 300°C for a duration between 15 minutes and 2 hours are performed.
T2 - Fatigue Design 2021
CY - Senlis, France
DA - 17.11.2021
KW - AlSi10Mg
KW - Additive manufacturing
KW - L-PBF
KW - Residual stress
KW - Heat treatment
PY - 2021
AN - OPUS4-53794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brunner-Schwer, Chr.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation on laser cladding of rail steel without preheating
N2 - The contact between train wheels and rail tracks is known to induce material degradation in the form of wear, and rolling contact fatigue in the railhead. Rails with a pearlitic microstructure have proven to provide the best wear resistance under severe wheel-rail interaction in heavy haul applications. High speed laser cladding, a state-of-the-art surface engineering technique, is a promising solution to repair damaged railheads. However, without appropriate preheating or processing strategies, the utilized steel grades lead to martensite formation and cracking during deposition welding.
In this study, laser cladding of low-alloy steel at very high speeds was investigated, without preheating the railheads. Process speeds of up to 27 m/min and laser power of 2 kW are used. The clad, heat affected zone and base material are examined for cracks and martensite formation by hardness tests and metallographic inspections. A methodology for process optimization is presented and the specimens are characterized for suitability. Within the resulting narrow HAZ, the hardness could be significantly reduced.
T2 - Lasers in Manufacturing Conference 2021
CY - Erlangen, Germany
DA - 21.06.2021
KW - High speed laser cladding
KW - Preheatin
KW - Rail tracks
KW - Pearlitic microstructure
PY - 2021
AN - OPUS4-53974
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Deland, Eric
A1 - Kleinbub, Sherin
T1 - Is Methanogen-induced microbiologically influenced corrosion (Mi-MIC) underestimated?
N2 - The role of methanogens in microbiologically influenced corrosion (Mi-MIC) is often neglected, due to 1) low reported corrosion rates and 2) the suspected corrosion product siderite, which is electrically non-conductive. Typically, MIC corrosion studies are carried out using batch cultures, which did not represent the dynamic conditions, i.e. pipeline and provide insufficient information on the overall corrosion potential.
We established a unique approach, a multiport flow column (MFC), to simulate pipeline conditions and obtained 10-times higher corrosion rates than previously published. Our result showed that testing procedures have a large impact on the corrosive potential of methanogens. We found strong indications with a combination of ToF-SIMS, SEM-EDS and FIB-SEM analyses that siderite is not the sole corrosion product. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of other environmental parameters (e.g. pH) on Mi-MIC.
T2 - VAAM 2021
CY - Online meeting
DA - 18.03.2021
KW - Methanogen-induced microbiologically influenced corrosion
KW - Carbon steel
KW - MIC Island
PY - 2021
AN - OPUS4-54042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strommer, Bettina
A1 - Battig, Alexander
A1 - Frasca, Daniele
A1 - Schulze, Dietmar
A1 - Huth, Christian
A1 - Böhning, Martin
A1 - Schartel, Bernhard
T1 - Multifunctional Property Improvements by Combining Graphene and Conventional Fillers in Chlorosulfonated Polyethylene Rubber Composites
N2 - The incorporation of nanoparticles like multilayer graphene (MLG) into elastomeric composites boosts their technical performance, such as their mechanical behavior and electrical conductivity. Common filler types (carbon black (CB) and aluminum trihydroxide (ATH)) generally fulfill single, specific purposes and are often used in high loadings. CB typically reinforces rubber mechanically, while ATH increases flame retardancy. Small amounts of MLG reduce these high filler contents and maintain the multifunctional characteristics of rubber composites. In chlorosulfonated polyethylene (CSM) + ATH, an intrinsically flame-retardant rubber was designed to achieve the highest standards such as maximum average of heat emission (MARHE) <90 kW m−2, 3 phrMLG was substituted for 15 phr CB and/or 3 phr ATH via an industrially applicable processing approach. Replacing either CB or ATH resulted in a property profile that was multifunctionally improved in terms of features such as mechanical performance, reduced sorption, and flame retardance. MLG nanocomposites are reported to show promise as an industrially utilizable route to obtain multifunctional high-performance rubbers.
KW - Nanocomposites
KW - Rubber
KW - Multilayer graphene
KW - Flame retardancy
KW - Synergy
KW - Nanoparticles
KW - Elastomers
PY - 2022
DO - https://doi.org/10.1021/acsapm.1c01469
SN - 2637-6105
VL - 4
IS - 2
SP - 1021
EP - 1034
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-54330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blasón Gonzalez, Sergio
A1 - Werner, Tiago
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Miarka, P.
A1 - Seitl, S.
A1 - Benedetti, M.
T1 - Determination of fatigue crack growth in the near-threshold regime using small-scale specimens
N2 - A complete description of the experimental procedure for characterizing the intrinsic fatigue crack propagation threshold (ΔKth,eff) as well as the fatigue crack growth rate (FCGR) in the near-threshold regime using small-scale specimens is presented. A comparative study is carried out on the high strength steel S960QL considering different single edge notch bend (SENB) specimen geometries. On one hand, the reference dimensions of 6 mm thickness (B) and 19 mm width (W) are analysed and referred to as conventional specimens. On the other hand, small-scale specimens with B = 3 mm and W = 4 and 6 mm are also considered. Several loading configurations (3-, 4- and 8-point bending) are used and a load ratio R = 0.8 is applied to avoid crack closure effects. The direct current potential drop (DCPD) technique is used to monitor the crack length. The reduced dimensions of the small-scale specimens imply the necessity of implementing a modified testing procedure compared to the recommendations of current standards for the generation of FCGR data. The results show a good agreement between tests conducted on different specimen sizes, which opens new perspectives in the use of small-scale specimens for characterizing the fatigue crack growth properties in metallic materials. Recommendations and limitations of the procedure are provided and discussed.
KW - Fatigue crack growth
KW - Small-scale specimens
KW - Intrinsic fatigue propagation threshold
KW - Near-threshold regime
KW - High-strength steel
KW - Alternative test procedure
PY - 2022
DO - https://doi.org/10.1016/j.tafmec.2021.103224
SN - 0167-8442
VL - 118
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Scheuschner, Nils
T1 - Infrared Thermography of the DED-LB/M and PBF LB/M processes
N2 - Infrared thermography is a technique that allows to measure the temperatures of objects by analyzing the intensity of the thermal emission without the need of direct contact with very high spatial and temporal resolution. As the temperature is a fundamental factor for the additive manufacturing processes of metals, infrared thermography can provide experimental data that can be used for the validation of simulations and improving the understanding of the processes as well as for in-situ process monitoring for nondestructive evaluation (NDE) for quality control.
In this talk we will provide an overview over the possibilities of state of the art thermographic in-situ monitoring systems for the DED-LB/M and PBF-LB/M processes and the challenges such as phase transitions and unknown emissivity values in respect to the determination of real temperatures. We define the requirements for different camera systems in various configurations and give examples on the selection of appropriate measurement parameters and data acquisition techniques as well as on techniques for data analysis and interpretation. Finally, we compare in-situ monitoring methods against post NDE methods by analyzing the advantages and disadvantages of both.
This research was funded by BAM within the Focus Area Materials.
T2 - Coupled2021 - IX International Conference on Coupled Problems in Science and Engineering
CY - Online meeting
DA - 13.06.2021
KW - Additive Manufacturing
KW - Thermography
KW - Direct Energy Deposition
PY - 2021
AN - OPUS4-54399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
T1 - Bruchmechanische Bewertung der Integrität einer Turbinenscheibe bei Überdrehzahl
N2 - Turbinenscheiben sind thermisch und mechanisch hochbeanspruchte, sicherheitsrelevante Komponenten in Gasturbinen. Ihre Integrität wird in Bauteiltests unter Überdrehzahlbedingungen nachgewiesen. Kontext des Aufsatzes ist die Erarbeitung einer zusätzlichen Bewertungsebene auf der Grundlage von Versuchen unter monotoner Beanspruchung, die die Beanspruchung im Bauteil realistisch wiedergeben soll. Betrachtet wird ein halbelliptischer Riss, der bei der weiteren Ausbreitung als Umfangsriss wächst (rim peeling). Die Simulation dieser Stelle im Bauteil schließt die mechanische und thermische Beanspruchung sowie sie Dehnungsbehinderung ein. Letztere wird anhand zweier Parameter, der Spannungsmehrachsigkeit ℎ und des (allerdings modifizierten) Constraint-Parameters nach Newman, der die Spannungen über den plastisch verformten Bereich mittelt, bestimmt. Erwartungsgemäß zeigt sich, dass die höchste Dehnungsbehinderung weder an den Oberflächenpunkten, noch an den tiefsten Punkten, sondern an einer Stelle zwischen beiden auf der Rissfront auftritt. Als Versuchsgeometrie für die monotonen Tests soll eine Kreuzprobe mit wanddurchdringenden Rissen ausgehend von einer Innenbohrung dienen. Durch geeignete Wahl der Risstiefe sowie der in beiden Richtungen angreifenden Kräfte gelingt es, bauteiladäquate Zustände zu erzeugen.
T2 - 54. Tagung des Arbeitskreis Bruchmechanik und Bauteilsicherheit
CY - Online meeting
DA - 22.02.2022
KW - Struktur Integrität
KW - Turbinenscheibe
KW - Constraint
KW - Bruchmechanik
PY - 2022
AN - OPUS4-54402
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Influence of an external applied AC magnetic field on the melt pool dynamics at high-power laser beam welding
N2 - The study deals with the determination of the influence of an externally applied oscillating magnetic field on the melt pool dynamics in high power laser beam and hybrid laser arc welding processes. An AC magnet was positioned under the workpiece which is generating an upward directed electromagnetic force to counteract the formation of the droplets. To visualise the melt flow characteristics, several experiments were carried out using a special technique with mild steel from S355J2 with a wall thickness of up to 20 mm and a quartz glass in butt configuration. The profile of the keyhole and the melt flow were recorded with a high-speed camera from the glass side. Additionally, the influence of the magnetic field orientation to the welding direction on the filler material dilution on laser hybrid welding was studied with variating oscillation frequency. The element distribution over the whole seam thickness was measured with X-ray fluorescence (XRF). The oscillation frequency demonstrated a greater influence on the melt pool dynamics and the mixing of the elements of the filler wire. The high-speed recordings showed, under the influence of the magnetic field, that the melt is affected under strong vortex at the weld root, which also avoids the formation of droplets
T2 - The 18th Nordic Laser Materials Processing Conference
CY - Lulea, Sweden
DA - 18.01.2022
KW - Laser beam welding
KW - Melt pool dinamics
PY - 2022
AN - OPUS4-54331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Accelerated Materials Discovery Based on Data Analysis and Machine Learning
N2 - The stability of materials is a very important property for materials discovery. In recent years, we have explored several approaches for advancing the prediction of the stability of crystals (e.g., classical chemical heuristics and machine-learned interatomic potentials). For example, we have assessed a famous chemical heuristic – the Pauling rules – regarding their usefulness for structure prediction. They are only of limited predictive power, i.e. the rules 2 to 5 only work for 13 % of all tested oxides. Furthermore, we have shown that machine-learned interatomic potentials can be used to predict phonon properties of a range of silicon allotropes accurately and, therefore, they can also be used to assess the dynamic stability of materials. To do so, we have developed new schemes to build reference databases for machine learned interatomic potentials.
T2 - PACRIM & GOMD 2021
CY - Online meeting
DA - 13.12.2021
KW - Data analysis
KW - Machine learning
KW - High-throughput computations
PY - 2021
AN - OPUS4-54088
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Garfias González, Karla I.
A1 - Schartel, Bernhard
T1 - Valorizing “non-vegan” bio-fillers: Synergists for phosphorus flame retardants in epoxy resins
N2 - Sustainable, biogenic flame retardant adjuvants for epoxy resins are receiving increased focus. Zoological products like insects, bone meal, and eggshells are available in large quantities, but remain uninvestigated as functional fillers to epoxy resins, although they are potential synergists to flame retardants. The efficacy and flame retardancy of “non-vegan” additives in combination with flame retardants is investigated and the fire behavior and thermal decomposition of bio-sourced epoxy resin composites is characterized. By comparing the fire performance of composites containing flame retardants or fillers at varying loadings (5, 10, and 20%), their role as synergists that enhance the function of organophosphorus flame retardants in bio-epoxy composites is identified and quantified. Peak heat release rates were 44% lower in composites containing both filler and flame retardant versus those containing only flame retardants, and fire loads were reduced by 44% versus the pure resin, highlighting the ability of “non-vegan” fillers to function as synergists.
KW - Flame retardancy
KW - Synergy
KW - Bio-composite
KW - Epoxy resin
KW - Biogenic
KW - Renewable
PY - 2022
DO - https://doi.org/10.1016/j.polymdegradstab.2022.109875
SN - 0141-3910
VL - 198
SP - 109875
PB - Elsevier Ltd.
AN - OPUS4-54438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
A1 - Radners, J.
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Aluminium high temperature fatigue
N2 - The studied aluminium alloy is EN AW-2618A (2618A). It is very widely used for exhaust gas turbo-charger compressor wheels. Due to long operating times, high cycle fatigue (HCF) and material aging under the influence of temperatures up to 230 °C is particularly relevant for the wheels. The wheels are typically milled from round wrought blanks. From such round blanks, different testpieces are extracted and a comprehensive series of HCF tests is conducted at room temperature. The tests investigate the materials fatigue performance in the T61 state for two load-ratios, namely R = -1 and R = 0.1. Additionally, two overaged material states are tested, accounting for the aging process the material undergoes during long operating times at high temperatures. The experimental results are evaluated and compared to each other.
Furthermore, the design process of notched specimens is presented. With the notched specimens, it is aimed to quantify the notch sensitivity of the material. Relating thereto, two potential model parameters for the fatigue lifetime model are introduced. Finally, the extended research data management in this project is highlighted and its advantages for sustainable use in material science and engineering applications are shown.
N2 - In diesem Projekt wird die Aluminiumlegierung EN AW-2618A (2618A) untersucht, welche sehr verbreitet in Verdichterrädern von Abgasturboladern zum Einsatz kommt. Hochzyklische Ermüdung und Werkstoffalterung bei Temperaturen von bis zu 230 °C ist bei Abgasturboladern aufgrund der langen Einsatzzeiten besonders relevant. Die Verdichterräder werden typischerweise aus geschmiedeten Rohlingen gefräst. Aus entsprechenden Rohlingen werden im Rahmen des Projekts eine Vielzahl von Proben mit unterschiedlichen Geometrien entnommen. Die Proben werden unter verschiedenen Prüfbedingungen in hochzyklischen Ermüdungsversuchen bei Raumtemperatur getestet. Zum einen wird das Ermüdungsverhalten des Werkstoffs im T61-Zustand für die zwei Belastungsverhältnisse R = -1 und R = 0,1 untersucht. Zum anderen werden zwei überalterte Materialzustände getestet. Damit soll dem Alterungsprozess Rechnung getragen werden, den das Material während langer Betriebszeiten bei hohen Temperaturen durchläuft. Die experimentellen Ergebnisse werden evaluiert und miteinander verglichen.
Darüber hinaus wird der Entwurfsprozess von gekerbten Probengeometrien dokumentiert. Die gekerbten Proben sollen Aufschluss über die Kerbempfindlichkeit des Werkstoffs geben. In diesem Zusammenhang werden zwei mögliche Modellparameter für das zu entwickelnde Lebensdauermodell vorgestellt. Abschließend wird das erweiterte Forschungsdatenmanagement des Projekts beleuchtet und seine Vorteile für die nachhaltige Nutzung in materialwissenschaftlichen und ingenieurtechnischen Anwendungen aufgezeigt.
T2 - FVV Frühjahrstagung 2022
CY - Würzburg, Germany
DA - 31.03.2022
KW - EN AW-2618A
KW - High cycle fatigue
KW - Aluminium alloy
PY - 2022
IS - FVV Publikationen Heft R602
SP - 617
EP - 634
PB - Forschungsvereinigung Verbrennungskraftmaschinen (FVV)
CY - Frankfurt am Main
AN - OPUS4-54622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Progress in the determination of the fatigue propagation resistance in metals and its application to fatigue assessment
N2 - This plenary lecture aims at showing the progress in the experimental determination of the fatigue propagation resistance in metals and its application to fatigue assessment. In particular, different new experimental techniques are introduced, which allow a better description of the crack propagation resistance from short to long crack regime. These data can be then applied in the fatigue assessment to predict the fatigue limit and the total life of metallic components.
T2 - 5th Iberian Conference on Structural Integrity
CY - Coimbra, Portugal
DA - 30.03.2022
KW - Crack propagation resistance
KW - Cyclic R-Curve
KW - Fatigue assessment
KW - Kitagawa-Takahashi diagram
KW - S-N diagram
PY - 2022
AN - OPUS4-54603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Accelerated materials discovery with data analysis and machine learning
N2 - Talk on my research on machine-learning and automation for students of TU Berlin.
T2 - TU Berlin Seminar
CY - Online meeting
DA - 24.01.2022
KW - Automation
KW - High-throughput
KW - DFT
PY - 2022
AN - OPUS4-54686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strommer, Bettina
T1 - Networking Skills: The Effect of Graphene on Crosslinking
N2 - 2D layered nanoparticles enable a distinct reduction of filler loadings in rubber compounds combined with a boost in performance due to their high surface to volume ratio. They often enable unique property profiles providing a great potential as effective fillers in rubber, especially by enhancing mechanical and barrier properties.
As the best possible incorporation into the elastomer matrix is crucial for the efficiency of the nanofiller, dispersing and exfoliation of the nanoparticles without formation of agglomerates usually constitutes an outstanding challenge - especially when using conventional processing methods. Laboratory-scale approaches for highly dispersed nanocomposites sometimes solve this problem, but these are often too energy and time consuming and provide no scale up possibility for real applications. Therefore, a latex premixing process was established to produce highly filled masterbatches, enabling the processing with conventional techniques.
The presence of nanoparticles greatly impacts the behavior of elastomeric compounds, besides affecting the properties of the final product also the processing is influenced (rheology, crosslinking).
In this study, nanocomposites of natural rubber and multilayer graphene (MLG) were prepared via a latex masterbatch route. Different strategies for masterbatch premixing are compared (stirring vs. ultrasonication, coagulation vs. drying). Dispersion and exfoliation of MLG were determined by transmission electron microscopy. The reinforcing effect of MLG affects the viscosity while the dispersed graphene layers may also act as diffusion barrier/absorbent for the crosslinking agents. In contrast to that, MLG forms physical crosslinks in the final product. Swelling measurements and differential scanning calorimetry allow a differentiation between chemical and physical network links. Different technical properties of the nanocomposites were measured with respect to mechanical and application relevant behavior.
T2 - PPS 37
CY - Online meeting
DA - 12.04.2022
KW - Elastomers
KW - Nanocomposites
KW - Graphene
KW - Nanoparticles
KW - Latex
KW - Natural rubber
KW - Processing
PY - 2022
AN - OPUS4-54696
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Roveda, Ilaria
T1 - Investigation of residual stresses and microstructure effects on the fatigue behaviour of a L-PBF AlSi10Mg alloy
N2 - Laser Powder Bed Fusion (L-PBF) allow the fabrication of lightweight near net shape AlSi10Mg components attractive to the aerospace, automotive, biomedical and military industries. During the build-up process, high cooling rates occur. Thus, L-PBF AlSi10Mg alloys exhibit a Si-nanostructure in the as-built condition, which leads to superior mechanical properties compared to conventional cast materials. At the same time, such high thermal gradients generally involve a deleterious residual stress (RS) state that needs to be assessed during the design process, before placing a component in service. To this purpose post-process heat treatments are commonly performed to relieve detrimental RS. In this contribution two low-temperature stress-relief heat treatments (SRHT) are studied and compared with the as-built state: a SRHT at 265°C for 1 hour and a SRHT at 300°C for 2 hours. At these temperatures microstructural changes occur. In the as-built state, Si atoms are supersaturated in the α-aluminium matrix, which is enveloped by a eutectic Si-network. At 265°C the Si precipitation from the matrix to the pre-existing network is triggered. Thereafter, above 295°C the fragmentation and spheroidization of the Si branches takes place, presumably by Al–Si interdiffusion. After 2 hours the original eutectic network is completely replaced by uniformly distributed blocky particles. The effect of the heat and the microstructure modification on the RS state and the fatigue properties is investigated. Energy dispersive x-ray and neutron diffraction are combined to investigate the near-surface and bulk RS state of a L-PBF AlSi10Mg material. Differences in the endurance limit are evaluated experimentally by high cycle fatigue (HCF) tests and cyclic R-curve determination.
T2 - 43rd Materials Mechanics Seminar
CY - Sani, Chalkidiki, Greece
DA - 05.06.2022
KW - AlSi10Mg
KW - Fatigue
KW - Neutron diffraction
KW - X-ray diffraction
PY - 2022
AN - OPUS4-55090
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding
N2 - Chemical heuristics are essential to understanding molecules and materials in chemistry. The periodic table, atomic radii, and electronegativities are only a few examples. Initially, they have been developed by a combination of physical insight and a limited amount of data. It is now possible to test these heuristics and generate new ones using automation based on Materials Informatic tools like pymatgen and greater amounts of data from databases such as a Materials Project. In this session, I'll speak about heuristics and design rules based on coordination environments and the concept of chemical bonding. For example, we have tested the Pauling rules which describe the stability of materials based on coordination environments and their connections on 5000 oxides from the Materials Project. In addition, we have created automated processes for analyzing the chemical bonding situation in crystalline materials with Lobster (www.cohp.de) in order to discover new heuristics and design rules.
T2 - Materials Project Seminar Series
CY - Online meeting
DA - 18.05.2022
KW - DFT
KW - Chemical heuristics
KW - Crystal Orbital Hamilton Populations
KW - Machine learning
KW - Phonons
PY - 2022
UR - https://www.youtube.com/watch?v=e7zYrz6fgog
UR - https://next-gen.materialsproject.org/community/seminar
AN - OPUS4-55008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Fracture mechanics fatigue life assessmente based on effective crack propagation data obtained at closure-free conditions
N2 - The use of effective crack propagation data, i.e. not affected by the crack closure mechanisms, is proposed as a reliable and robust alternative for the fatigue life assessment of cyclically loaded components.
T2 - 43rd Materials Mechanics Seminar
CY - Sani, Greece
DA - 05.06.2022
KW - Effective crack propagation data
KW - Crack-closure
KW - Component assessment
PY - 2022
AN - OPUS4-55044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zhu, Jiangchao
T1 - Fracture mechanics-based structural integrity assessment of aero-engine turbine disks under overspeed conditions
N2 - Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on production-similar disks. While these tests provide, on the one hand, a reliable definition of the critical conditions for real components, on the other hand they represent a relevant cost item for engine manufacturers. The aim of this work is to present part of a fracture mechanics-based procedure under development which aims at replacing the tests on production-similar disks with lab tests on fracture mechanics specimens. In particular, the rim-peeling failure mode is considered as case study. A semi-circular surface crack is modelled at the most stressed region at the diaphragm of a turbine disk, with the crack plane perpendicular to the radial direction. The crack is therefore subjected to a biaxial stress state and grows under increasing rotational speed until it triggers the rim-peeling failure. The finite element simulation of the cracked disk considers the real thermal and mechanical loading conditions. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of J-integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. This has been achieved and as expected, both the highest J-integral and constraint factor are calculated at the same location along the crack front for both disk and specimen. The results of the structural integrity assessment in the form of a Failure Assessment Diagram (FAD) show good agreement between designed specimen and disk both in terms of expected failure mode and value of the critical speed. Probabilistic aspects are also considered in the calculations.
T2 - Turbo Expo 2022
CY - Rotterdam, Netherlands
DA - 13.06.2022
KW - Structural integrity
KW - Fracture mechanics
KW - Turbine disk
KW - Overspeed
PY - 2022
AN - OPUS4-55082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ciornii, Dmitri
T1 - Interlaboratory Comparisons – ILCs (2022-2023)
N2 - To obtain reliable data on micro- and nanoplastics (MPs, NPs) BAM (Federal Institute for Materials Research and Testing) is organizing interlaboratory comparisons (ILCs). Main focus is detection and physico-chemical characterisation. The accuracy and precision of the results of different laboratories and comparability of the results among the participants are addressed. The ILCs will be performed in the following order: i) ILC #1: Detection and Characterisation of MPs (1-1000 µm) and ii) ILC #2: Detection and Characterisation of NPs (< 1 µm).
For the ILC #1 the parameters to be analysed are: particle size distribution, shape, mass content, particle concentration, with thermoanalytic (Py-GC/MS, TED-GC/MS) and spectroscopy (µ-Raman, µ-FTIR) methods. For the ILC #2 the parameters are: particle size distribution, shape, particle concentration, with methods such as spectroscopical (Raman), Electron Microscopies (SEM, AFM), etc. Exact measurands and methods are still under discussion. BAM will provide test materials of well-known stability and homogeneity. ILC participants will include partners of the CUSP (the European research cluster to understand the health impacts of micro- and nanoplastics), and any other institutions over the world. The ILCs will take place under the international pre-standardisation platform VAMAS, new Technical Working Area 35 “Micro and Nano Plastics in the Environment” (http://www.vamas.org/twa45/).
T2 - Progressing Together: 2nd CUSP Annual Meeting at the JRC (Ispra)
CY - Ispra, Italy
DA - 08.06.2022
KW - ILC
KW - Micro- and nanoplastics
KW - VAMAS
KW - Analytical methods
PY - 2022
AN - OPUS4-55097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Zerbst, Uwe
A1 - Madia, Mauro
ED - Yadroitsev, I.
ED - Yadroitsava, I.
ED - Du Plessies, A.
ED - McDonald, E.
T1 - Structural integrity II: fatigue properties
N2 - If a component is cyclically loaded, its load carrying capacity is considerably lower than in the monotonic loading case. This general observation applies in particular to L-PBF parts. The causes of this are mainly material defects such as pores and unwelded regions (Chapter 8) and a pronounced surface roughness in the as-built condition (Chapter 9). In addition, effects due to the anisotropy of the microstructure (Chapter 6) and a complex residual stress pattern (Chapter 7) play an important role. A consequence is that common strategies of fatigue assessment cannot be transferred to L-PBF applications without modifications. Due to the inhomogeneity of the material, the determination of representative material properties and the transfer to the component is a problem, and this is also the case with regard to the consideration of defects, surface roughness and residual stresses. The chapter gives a brief introduction to these problem areas.
KW - Fatigue crack propagation stagesdefects
KW - Fatigue strength
KW - Fatigue life
KW - Fracture mechanics
PY - 2021
SN - 978-0-12-824090-8
DO - https://doi.org/10.1016/B978-0-12-824090-8.00015-9
SP - 377
EP - 394
PB - Elsevier Inc.
CY - Amsterdam
ET - 1
AN - OPUS4-52854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Schafner, A.
A1 - Raute, J.
A1 - Rethmeier, Michael
T1 - Relative density prognosis for directed energy deposition with the help of artificial neural networks
N2 - Additive manufacturing, and therefore directed energy deposition, is
gaining more and more interest from industrial users. However, quality assurance for the components produced is still a challenge. Machine learning, especially using artificial neuronal networks, is a potential method for ensuring a high-quality standard. Based on process Parameters and monitoring data, part quality can be predicted. A further advantage is the ability to constantly learn and adopt to slight process changes.
First tests using artificial neural networks focus on the prediction of track geometry. The results show that even a small data set is enough to provide high accuracy in the predictions. In this work, an artificial neural network for the predictive analysis of relative density in laser powder cladding has been developed. A central composite experimental design is used to generate 19 data sets. Input variables are laser power, feed rate and powder mass flow. Cubes are built up where density is considered as a target value. Several neural networks are trained and evaluated with these data sets. Different topologies and initial weights are considered. The best network reaches a confidence level of around 90 % for the prediction of relative density based on the process parame� ters. Finally, the optimization of the generalization performance is investigated. To this purpose, methods of variation in error limit as well as cross-validation are applied. In this way, density is predictable by an artificial neural network with an accuracy of about 95 %.
KW - Directed energy deposition
KW - Artificial neural network
PY - 2021
DO - https://doi.org/10.1515/mt-2020-0004
SN - 0025-5300
VL - 63
IS - 1
SP - 41
EP - 47
PB - DE Gruyter
CY - Berlin
AN - OPUS4-52690
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Investigation on the influence of different testing methods and parameters on the determination of fatigue crack growth data
N2 - The correct determination of fatigue crack propagation data is of great importance for the damage tolerance design of engineering components, especially with regard to the calculation of residual lifetime and the establishment of inspection intervals. The fatigue crack propagation threshold Δ𝐾th, in this respect, is a crucial input parameter for simulating crack growth, since it corresponds to the stress intensity factor range at which a non-growing crack starts to propagate. However, the experimental determination of Δ𝐾th, as well as its application, is still confronted with few issues related among others to the load ratio (R) dependency of Δ𝐾th, the testing procedure, and environmental effects. These can lead to large scatter and significant errors in the prediction of component failure. In this context, the use of the intrinsic fatigue crack propagation threshold Δ𝐾th,eff in component assessment is a promising alternative, since it does not depend on a number of factors that affect Δ𝐾th, but only on the elastic properties (𝐸-modulus) and the lattice (Burger’s vector ‖𝑏‖) of the material. The aim of the present work is therefore to investigate different experimental procedures for the determination of Δ𝐾th,eff, namely: (a) conventional load reduction (LR) procedures, (b) the 𝐾max procedure and (c) compression pre-cracking load reduction and constant amplitude (respectively CPLR and CPCA) methods. Furthermore, the determination of Δ𝐾th has been carried out varying some testing parameters, such as test frequency, Δ𝐾 at the beginning of the crack propagation test (Δ𝐾0) and stress ratio (R). The results are statistically analyzed and a discussion about the use of Δ𝐾th and Δ𝐾th,eff for the component fatigue assessment is presented.
T2 - 6th. International Virtual Conference of Engineering Against Failure
CY - Online meeting
DA - 23.06.2021
KW - Crack closure
KW - Damage tolerance assessment
KW - Residual lifetime
KW - Intrinsic fatigue crack propagation threshold
PY - 2021
AN - OPUS4-52899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automatisierung in der Computerchemie
N2 - Im Vortrag wird der aktuelle Stand zur Automatisierung in der Computerchemie und der computergestützten Materialwissenschaft besprochen.
T2 - Online-Workshop des Fördervereins Chemieolympiade 2021
CY - Online meeting
DA - 19.06.2021
KW - Computergestützte Materialwissenschaft
KW - Automatisierung
KW - Hochdurchsatz
KW - Computerchemie
PY - 2021
AN - OPUS4-52981
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Interconnecting data repositories: The Platform MaterialDigital (BMBF)
N2 - Presentation of the Platform MaterialDigital. Presentation of the needs and challenges in materials science and engineering.
T2 - 3rd EMMC International Workshop - EMMC
CY - Online meeting
DA - 02.03.2021
KW - Digitization
KW - Standardization
KW - Ontology
PY - 2021
AN - OPUS4-52247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
T1 - Automation in DFT-based computational materials science
N2 - Automation simplifies the use of computational materials science software and makes it accessible to a wide range of users. This enables high-throughput calcula-tionsand makesiteasier for non-specialists to enter computational materials science. However, in-creasing automation also poses threats that should be considered while interacting with automated procedures.
KW - DFT
KW - Automation
KW - High-throughput computations
PY - 2021
DO - https://doi.org/10.1016/j.trechm.2021.07.001
SN - 2589-5974
VL - 3
IS - 9
SP - 697
EP - 699
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53127
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Battig, Alexander
T1 - Multifunctional Graphene in Flame Retarded Polybutadiene/ Chloroprene/ Carbon Black Composites
N2 - Multilayer graphene is investigated as a multifunctional nanofiller to polybutadiene/ chloroprene rubbers (BR/CR) that partially substitutes carbon black (CB) and aluminum trihydroxide (ATH). Loadings of only 3 parts per hundred rubber (phr) MLG replaced 15 phr of CB and/or 3 phr of ATH in BR/CR nanocomposites. Mechanical and fire behavior were investigated, and results point to improved rheological, curing and mechanical properties of MLG-containing rubber composites.
T2 - 18th European Meeting on Fire Retardant Polymeric Materials, FRPM21
CY - Budapest, Hungary
DA - 29.08.2021
KW - Graphene
KW - Rubber
KW - Fire Retardant
KW - Nanofiller
KW - Nanocomposite
KW - ATH
PY - 2021
AN - OPUS4-53202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Maiwald, Michael
A1 - Villajos, José Antonio
T1 - Metal-organic framework compounds as hydrogen storage materials to enhance the safety, capacity, and efficiency of hydrogen refueling stations
N2 - Gas adsorption is based on physical properties between gases and solid materials, enriching the surface with packed gas molecules with a higher density than in the bulk phase. For using this mechanism as a gas storage strategy, highly porous materials are necessary since large surfaces in small volumes can provide the storage system with a higher density than the gas phase. In the case of hydrogen gas, the interaction forces with solid surfaces are generally low at room temperature but can increase considerably at low operating temperatures. As a counterpart, the storage pressure is considerably lower than that necessary by traditional gas compression.
Amongst ultra-porous adsorbent materials for hydrogen cryoadsorption, metal-organic frameworks (MOFs) are a group of remarkable solids made from metallic nodes linked by organic molecules exhibiting a wide variety of composition, geometry, porous properties, and chemical functionality. The scientific community focused in the last years on enhancing both the specific area of materials and the interaction energy to extend the storage properties of cryoadsorption to ambient-temperature and use it as hydrogen storage mechanisms in vehicles. However, the found difficulty in achieving ultra-porous structures with high-enough interaction energies decreased this research interest in the last years.
However, for a stationary application like hydrogen refueling stations, where space and weight are not such limits as in vehicles, cryoadsorption can still be considered a feasible candidate for hydrogen storage. Cryoadsorption is the only fast and fully reversible approach to store hydrogen at similar density values as compressed gas. Cryogenic operation is a technological challenge, but first, liquid nitrogen is cheap, and second, it is less energy-demanding than hydrogen liquefaction, which is indeed considered as feasible for transportation and storage. Cryoadsorption involves lower pressure
than compressed gas, increasing safety in the storage facilities, but additional research on the construction materials properties is necessary to better understand their behavior in contact with hydrogen at cryogenic temperatures. However, the knowledge of all these mechanisms is important to identify the improvement opportunities based on, probably, the interphase between different solutions.
To achieve the set project goals, this internal research report describes the work packages realised within the framework of the project.
KW - Metal-organic frameworks (MOFs)
KW - Hydrogen Storage
KW - Reversible Hydrogen Storage
KW - Hydrogen Fuelling Stations
KW - Croyo-starage
KW - High-pressure volumetric analyzer (HPVA)
PY - 2021
SP - 1
EP - 48
CY - Berlin
AN - OPUS4-53582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automation in Computational Materials Science
N2 - The talk „Automation in computational materials science“ deals with the current state of automation in the field of computational materials science. It illustrates how automation can, for example, be used to speed up the search for new ferroelectric materials and spintronic materials. Furthermore, it lists current tools for automation and challenges in the field.
T2 - SALSA School 2021
CY - Online meeting
DA - 16.09.2021
KW - Automation
KW - High-throughput
PY - 2021
AN - OPUS4-53483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishurova, Tatiana
T1 - Separation of the impact of residual stress and microstructure on the fatigue performance of LPBF Ti-6Al-4V at elevated temperature (Keynote)
N2 - Ti-6Al-4V alloy is intensively used in the aerospace industry because of its high specific strength. However, the application of Laser Powder Bed Fusion (LPBF) Ti-6Al-4V alloy for structurally critical load-bearing components is limited. One of the main limiting factors affecting the structural integrity, are manufacturing defects. Additionally, the high cooling rates associated with LPBF process result in the formation of large residual stress (RS) with complex fields. Such RS can cause cracking and geometrical distortions of the part even right after production. Also, the microstructure of LPBF Ti-6Al-4V in the as-built condition is significantly different from that of the conventionally produced alloy. All these factors affect the mechanical behavior of the material. Therefore, to improve the material performance it is important to evaluate the individual effect of RS, defects, and microstructure on fatigue life. To this aim Ti-6Al-4V LPBF material in as-built condition and subjected to different post-processing, including two heat treatments (for stress relief and microstructural modification) and Hot Isostatic Pressing (HIP, for densification), were investigated.
Prior to fatigue tests at elevated temperature, the microstructure, the mesostructure, and subsurface RS on the fatigue samples were investigated. It was found that the fatigue performance of HIPped samples is similar to that of conventionally produced Ti-6Al-4V. The tensile RS found at the surface of as-built samples decreased the fatigue life compared to heat-treated samples. Additionally, the modification of the microstructure (by heat treatment) did not affect the fatigue performance in the regime of mostly elastic strain. This shows that in the absence of tensile RS the manufacturing defects solely control the failure of LPBF components and densification has the strongest effect on the improvement of the mechanical performance.
T2 - EUROMAT 2021
CY - Online meeting
DA - 12.09.2021
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Residual stress
KW - Fatigue performance
PY - 2021
AN - OPUS4-53278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Towards digitalization of materials in PMD: An application ontology of the tensile test
N2 - Due to the diversity of materials and the processes associated with their production and use, the complexity of the lifecycles of materials and the multitude of academic and industrial researchers participating in generation of data for material design impose a huge challenge. The topical goal of digitalizing materials and processes can only be adequately addressed by consolidating the efforts of all stakeholders in this field. There are many scattered activities, but there is a demand for an elimination of redundancies as well as an advance in acceptance and a common basis in the digitalization of materials. Furthermore, data analysis methods play an important role in both, the experimental and simulation-based digital description of materials, but they have been poorly structured so far.
Therefore, the two joint projects Platform Material Digital (PMD, materialdigital.de) and Materials open Laboratory (Mat-o-Lab, matolab.de) aim to contribute to a standardized description of data processing methods in materials research. Besides stimulating the formation of a collaborative community in this respect, their main technical goals are the quality assurance of the processes and the output data, the acquisition and definition of their accuracy as well as the interoperability between applications. In this regard, data management in accordance with the FAIR (findability, accessibility, interoperability, reuseability) principles is addressed. There is a common agreement in the scientific community following current discussions that data is supposed to be conform to these principles. This includes storage, processing and querying of data in a preferably standardized form.
To meet the challenge to contextualize material data in a way that is consistent with all stakeholders, all necessary information on the condition of the material including production and application-related changes have to be made available via a uniform, machine-readable description. For this purpose, ontologies are to be used since they allow for machine-understandable knowledge representations and conceptualizations that are needed for data management and the digitalization in the field of materials science.
As first efforts in PMD and Mat-o-Lab, application ontologies are created to explicitly describe processes and test methods. Thereby, the well-known tensile test of metals at room temperature was described ontologically in accordance with the respective ISO standard 6892-1:2019-11.
The efforts in creating this tensile test application ontology are shown in this presentation. Especially, the path of ontology development based on standards to be pursued is focused, which is in accordance with the generic recommendations for ontology development and which is supposed to be exemplary for the creation of other application ontologies.
T2 - VirtMet: 1st International Workshop on Metrology for Virtual Measuring Instruments and Digital Twins
CY - Online meeting
DA - 21.09.2021
KW - Platform Material Digital (PMD)
KW - Ontology
KW - Tensile test
KW - Standard
KW - Ontology development
PY - 2021
AN - OPUS4-53481
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support
N2 - One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds.
T2 - X International Conference «Beam Technologies in Welding and Materials Processing»
CY - Odessa, Ukraine
DA - 7.09.2021
KW - Laser beam welding
KW - Hybrid laser arc welding
KW - Material transport
PY - 2021
AN - OPUS4-53569
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Üstündag, Ömer
T1 - Elektromagnetische Schmelzbadbeeinflussung beim Laserhybridschweißen von Dickblechen
N2 - -Elektromagnetische Schmelzbadstütze wurde beim
Laserhybridschweißen von Dickblechen erfolgreich zur
Unterdrückung der Tropfenbildung eingesetzt
-Auch bei „schlechteren“ Kantenqualitäten konnten einlagige
Schweißnähte mit hoher Qualität erzielt werden
-Spaltüberbrückbarkeit bis zu 2 mm (bei plasmageschnittenen
Proben) konnte gewährleistet werden
-Homogenere Verteilung des Zusatzwerkstoffes wurde erzielt
T2 - 42. Assistentenseminar der Wissenschaftlichen Gesellschaft Fügetechnik e.V.
CY - Blankenau (Beverungen), Germany
DA - 06.10.2021
KW - Laserhybridschweißen
KW - Elektromagnetische Schmelzbadbeeinflussung
KW - Dickblech
PY - 2021
AN - OPUS4-53578
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rethmeier, Michael
A1 - Gumenyuk, Andrey
A1 - Bachmann, Marcel
T1 - High-power laser beam welding for thick section steels – new perspectives using electromagnetic systems
N2 - In recent years, it was shown that the introduction of additional oscillating and permanent magnetic fields to laser beam and laser-arc hybrid welding can bring several beneficial effects.
Examples are a contactless weld pool support for metals of high thickness suffering from severe drop-out when being welded conventionally or an enhanced stirring to improve the mixing of added filler material in the depth of the weld pool to guarantee homogeneous resulting mechanical properties of the weld. The latest research results show the applicability to various metal types over a wide range of thicknesses and welding conditions. The observations made were demonstrated in numerous experimental studies and a deep understanding of the interaction of the underlying physical mechanisms was extracted from numerical calculations.
KW - Laser beam welding
KW - Numerical simulations
KW - Electromagnetic support
PY - 2021
DO - https://doi.org/10.1080/13621718.2021.1999763
VL - 27
IS - 1
SP - 43
EP - 51
PB - Taylor & Francis Group
AN - OPUS4-53970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Einflussfaktoren auf die Bestimmung von Rissfortschrittsdaten
N2 - Rissfortschrittsdaten sind notwendig für die bruchmechanische Bewertung zyklisch beanspruchter Bauteile. Deren zuverlässige experimentelle Ermittlung wird von verschiedenen Faktoren beeinflusst, was wiederum zur Unsicherheit bei der Restlebensdauerprognose führen kann. Der Vortrag befasst sich mit der Untersuchung der Einflussfaktoren auf die Ermittlung von Rissfortschrittsdaten. Eine Prozedur zur Berechnung der Restlebensdauer wird eingeführt, die auf rissschließfrei Rissfortschrittsdaten basiert.
T2 - 42. Werkstoffmechanikseminar 2021
CY - Online meeting
DA - 11.10.2021
KW - Rissfortschrittsdaten
KW - Einflussfaktoren
KW - Restlebensdauerprognose
PY - 2021
AN - OPUS4-53615
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Determination of fatigue crack propagation thresholds using small scale specimens
N2 - The damage tolerance approach is widely used in the design and estimation of inspection intervals of safety-relevant metallic components subject to fatigue loading. The approach relies on the knowledge of the fatigue crack propagation characteristics, wherein a relevant role is played by the fatigue crack propagation threshold. Nevertheless, the use of material data determined by testing on conventional specimens is not straightforward in case of thin-walled components such as turbine-blades or additively manufactured parts, in which the local variation of material properties in highly stressed regions must be considered. In these cases, the possibility of investigating the fatigue crack propagation properties on a limited portion of material is crucial. For this purpose, a new test methodology has been developed for small-scale specimens which allows the determination of the intrinsic fatigue crack propagation threshold and the near-threshold regime. The use of small-scale specimens poses a challenge to the applicability of the method to metallic materials, especially regarding the
limitations on material strength and requirements for the application of the linear elastic fracture mechanics concepts. These aspects are discussed in this work. Furthermore, the application on the high strength steel S960QL is presented, along with a comparison with data determined by conventional testing.
T2 - Fatigue Design 2021
CY - Online meeting
DA - 17.11.2021
KW - Small scale testing
KW - Fatigue crack growth
KW - Threshold regime
PY - 2021
AN - OPUS4-53781
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - The effect of the environmental conditions on the threshold against fatigue crack propagation
N2 - The threshold against fatigue crack propagation (ΔKth) is a crucial parameter for the damage tolerance assessment of engineering components subjected to cyclic loading and it is composed by two distinct components, one intrinsic, dependent on the elastic material properties and the lattice type, and one extrinsic, related to the occurrence of crack closure effects. An important issue is that several factors can influence ΔKth and, in general, the fatigue crack propagation behavior. In this work, the influence of the experimental procedure, air humidity and test parameters on da/dN-ΔK data has been investigated. Results are discussed with their potential causes and consequences on the calculations of the residual lifetime.
T2 - Conference Fatigue Design 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue crack propagation threshold
KW - Crack closure effect
KW - Experimental procedure
KW - Environmental conditions
PY - 2021
AN - OPUS4-53770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Wie digitalisieren wir die Werkstoffprüfung? Entwicklung standardisierter Versuchsbeschreibungen und Daten-Infrastrukturen in aktuellen Digitalisierungs-Initiativen
N2 - Die Entwicklung digitaler Prozesse für die Materialwissenschaft und Werkstofftechnik muss naturgemäß auch die Charakterisierungsmethoden der Werkstoffprüfung abbilden, die oft durch eine hohe Komplexität gekennzeichnet sind. Als vorteilhaft erweist sich dabei der hohe Standardisierungsgrad, der sich z.B. in klaren Anforderungen an die eingesetzten Prüfmittel und festgelegten Vorgehensweisen ausdrückt. Diese können (und müssen) in entsprechenden digitalen Versuchsbeschreibungen abgebildet werden, wobei sich die klaren Datenstrukturen und Terminologien als vorteilhaft erweisen.
T2 - Tagung Werkstoffprüfung 2021: Werkstoffe und Bauteile auf dem Prüfstand Prüftechnik – Kennwertermittlung – Schadensvermeidung
CY - Online meeting
DA - 02.12.2021
KW - Digitalisierung
KW - Standardisierung
KW - Normung
KW - Ontologien
KW - Wissensrepräsentation
PY - 2021
AN - OPUS4-53943
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kempf, A.
T1 - Correlation between quasistatic und fatigue properties of additively manufactured AlSi10Mg using Laser Powder Bed Fusion
N2 - In order to find a resource efficient approach for the fatigue lifetime prediction of laser powder bed fusion (L-PBF) processed AlSi10Mg material, results of tensile and fatigue tests were compared. The specimens were manufactured with three different L-PBF machines and studied in different heat treatment conditions (as-built, annealed, T6 heat treated). The investigations showed that the high attainable tensile strength properties after the manufacturing process are not beneficial in the high cycle fatigue (HCF) regime. In contrast, the applied heat treatments, which lead typically to a decrease of ultimate tensile strength, improved dramatically the fatigue behavior. Additionally, a clear correlation between the elongation at fracture and HCF resistance has been found for individual heat treatment conditions. This empiric relationship provides an estimation of the fatigue resistance in the presence of material defects and can be implemented in part and process approvals.
T2 - Fatigue Design 2021
CY - Online meeting
DA - 17.11.2021
KW - Additive Manufacturing
KW - Laser powder bed fusion
KW - AlSi10Mg
KW - Tensile properties
KW - Fatigue properties
PY - 2021
AN - OPUS4-53792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Estimation of the Kitagawa-Takahashi diagram by cyclic R-curve analysis
N2 - The Kitagawa-Takahashi (KT) diagram is a proven concept for describing the fatigue limit in presence of a defect or crack. It can be determined empirically with great experimental effort. It can also be estimated by means of the El Haddad relationship if the endurance limit and the long fatigue crack propagation threshold are available in reasonable accuracy. A third option is the determination using the cyclic R-curve, which describes the dependency of the fatigue crack propagation threshold on the crack growth at the short crack propagation stage. This can be experimentally determined using a closure-free initial pre-crack. It can then be applied to the determination of crack arrest for a given applied load and a given defect or crack size. Compared to the other two methods mentioned above, this option has considerable advantages: It can be applied to any component and any stress ratio. It allows the treatment of multiple cracks and provides estimations of the S-N curve in the finite life regime as well as at the endurance limit. Compared to the empirical determination of the KT diagram, the experimental effort is significantly lower and compared to the El Haddad approach it avoids problems such as the use of non-conservative long fatigue crack propagation thresholds (when the conventional load reduction method is applied to materials prone to corrosion) and the mathematical predetermination of the curve shape. The work introduces the method and provides a critical discussion as well as quantitative comparison between the different methods.
T2 - Fatigue Design 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue life
KW - Endurance limit
KW - Kitagawa-Takahashi diagram
KW - Cyclic R-curve
PY - 2021
AN - OPUS4-53778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Werner, Tiago
T1 - Comparison of the fatigue behavior of wrought and additively manufactured AISI 316L
N2 - Additively Manufactured (AM) parts are still far from being used in safety-relevant applications, mainly due to a lack of understanding of the feedstock-process-propertiesperformance relationship. This work aims at providing a characterization of the fatigue behavior of the additively manufactured AISI 316L austenitic stainless steel and a direct comparison with the fatigue performance of the wrought steel. A set of specimens has been produced by laser powder bed fusion (L-PBF) and a second set of specimens has been machined out of hot-rolled plates. The L-PBF material shows a higher fatigue limit and better finite life performance compared to the wrought material, accompanied by an extensive amount of cyclic softening.
T2 - Fatigue Design 2021
CY - Online meeting
DA - 17.11.2021
KW - Additive Manufacturing
KW - AM
KW - 316L
KW - Fatigue
KW - High Cycle Fatigue
KW - Low Cycle Fatigue
PY - 2021
AN - OPUS4-53780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Bruno, Giovanni
A1 - Buffière, J.-Y.
A1 - Wegener, T.
A1 - Niendorf, T.
A1 - Wu, T.
A1 - Zhang, X.
A1 - Kashaev, N.
A1 - Meneghetti, G.
A1 - Hrabe, Nik
A1 - Madia, Mauro
A1 - Werner, Tiago
A1 - Hilgenberg, Kai
A1 - Koukolikova, M.
A1 - Prochazka, R.
A1 - Dzugan, J.
A1 - Möller, B.
A1 - Beretta, S.
A1 - Evans, Alexander
A1 - Wagener, R.
A1 - Schnabel, K.
T1 - Damage tolerant design of additively manufactured metallic components subjected to cyclic loading: State of the art and challenges
N2 - This article is an outcome of a workshop on Fatigue of Additive Manufactured Metallic Components jointly organized by the Federal Institute for Materials Research and Testing (BAM) Berlin, Germany and the National Institute of Standards and Technology (NIST) Boulder, CO, U.S.A. The aim of the workshop was a comprehensive discussion of the specific aspects of additively manufactured (AM) components in regard to failure under cyclic loading. Undoubtedly, a better understanding and the further development of approaches for damage tolerant component design of AM parts are among the most significant challenges currently facing the use of these new technologies.
This article presents a thorough overview of the workshop discussions. It aims to provide a review of the parameters affecting the damage tolerance of AM parts with special emphasis on the process parameters intrinsic to the AM technologies, the resulting defects and residual stresses. Based on these aspects, concepts for damage tolerant component design for AM are reviewed and critically discussed.
KW - Additive manufacturing
KW - Fatigue loading
KW - Component assessment
KW - Damage tolerance
KW - Defects
KW - Residual stresses
PY - 2021
DO - https://doi.org/10.1016/j.pmatsci.2021.100786
SN - 0079-6425
VL - 121
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Böllinghaus, Thomas
A1 - Rhode, Michael
A1 - Falkenreck, T.
ED - Bender, B.
ED - Göhlich, D.
T1 - Korrosion und Korrosionsschutz
N2 - Das Kapitel beginnt mit einer kurzen Einführung über die Korrosion (Wechselwirkung zwischen einem Metall, einer korrosiven Umgebung und der der jeweiligen Konstruktion). Im zweiten Abschnitt werden die wichtigsten Formen der wässrigen elektrochemischen Korrosion (Flächenkorrosion, galvanische, selektive und interkristalline Korrosion sowie Loch- und Spaltkorrosion) betrachtet. Darüber hinaus wird die elektrochemische Korrosion unter mechanischer Belastung betrachtet (Spannungsrisskorrosion, wasserstoffunterstützte Rissbildung, Korrosionsermüdung), sowie Sonderformen der Korrosion (Erosion, Fretting und mikrobiologisch induzierte Korrosion). Der dritte Abschnitt befasst sich mit der chemischen und Hochtemperaturkorrosion (Oxidation, Aufkohlung, Hochtemperatur-Wasserstoffangriff, Aufschwefelung, Nitrierung, Halogenierung). Zusätzlich enthält das Kapitel Maßnahmen zur Vermeidung der Korrosion.
KW - Korrosion
KW - Korrosionsschutz
KW - Spannungsrisskorrosion
KW - Wasserstoff
KW - Loch- u. Spaltkorrosion
PY - 2021
SN - 978-3-662-59710-1
DO - https://doi.org/10.1007/978-3-662-59711-8_34
VL - 1
SP - 691
EP - 725
PB - Springer-Verlag GmbH, ein Teil von Springer Nature
CY - Berlin
ET - 26
AN - OPUS4-52156
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonego, M.
A1 - Madia, Mauro
A1 - Eder, M.
A1 - Fleck, C.
A1 - Pessan, L. A.
T1 - Microstructural features influencing the mechanical performance of the Brazil nut (Bertholletia excelsa) mesocarp
N2 - Brazil nut (Bertholletia excelsa) fruits are capable of resisting high mechanical forces when released from trees as tall as 50 m, as well as during animal dispersal by sharp-teethed rodents. Thick mesocarp plays a crucial part in seed protection. We investigated the role of microstructure and how sclereids, fibers, and voids affect nutshell performance using compression, tensile and fracture toughness tests. Fractured specimens were analyzed through scanning electron microscopy (SEM) and microtomography (microCT). Mesocarp showed high deformability (strain at max. stress of ~30%) under compression loading, a critical tensile strength of ~24.9 MPa, a Weibull modulus of ~3, and an elastic modulus of ~2 GPa in the tensile test. The fracture toughness, estimated through the work of fracture of SENB tests, reached ~2 kJ/m2. The thick and strong walls of mesocarp cells, with a weaker boundary between them (compound middle lamella), promote a tortuous intercellular crack path. Several toughening mechanisms, such as crack deflection, breaking of fiber bundles, fiber pullout and bridging as well as crack branching, occur depending on how fiber bundles and voids are oriented.
KW - Toughening mechanisms
KW - Brazil nut Mesocarp
KW - Microstructure
KW - Mechanical properties
PY - 2021
DO - https://doi.org/10.1016/j.jmbbm.2020.104306
VL - 116
SP - 104306
PB - Elsevier Ltd.
AN - OPUS4-52081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Braun, Ulrike
T1 - Detektion von Mikroplastik in Flaschenwasser mittels thermoanalytischer Verfahren
N2 - Im Vortrag wird ein Messfiltertiegel als Zusatztool für die TED-GC/MS vorgestellt, welcher für die Probenaufbereitung von kleinen Partikelfrachten oder kleinen Partikelgrößen genutzt werden kann. Er ist Filtereinheit und Messtiegel in einem, wodurch Verluste bei der Überführung der Probe in das Messgefäß sowie Kontaminationen vermindert werden. Das beispiel ist hier die Filtration von Flaschenwasser mit anschließender Detektion mit der TED-GC/MS.
T2 - BVL_Kick-off Meeting "Mikroplastik in Lebensmitteln"
CY - Online meeting
DA - 03.12.2020
KW - Mikroplastik
KW - TED-GC/MS
KW - Kleine Partikel
KW - Geringe Partikelfrachten
KW - Mikroplastik-Massengehalte
PY - 2020
AN - OPUS4-51794
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Dittmann, Daniel
T1 - Experimental raw data for "Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine"
N2 - This is the repository of all experimental raw data used in the Scientific Reports publication "Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine" by Daniel Dittmann, Paul Eisentraut, Caroline Goedecke, Yosri Wiesner, Martin Jekel, Aki Sebastian Ruhl, and Ulrike Braun.
It includes
- overview_measurements.xlsx and overview_measurements.ods containing a list of all TGA experiments (TGA, TGA-FTIR, TED-GC-MS, and ramp-kinetics)
- TED-GC-MS.zip containing gas chromatography-mass spectrometry experimtent files for the Chemstation and OpenChrom
- TGA.zip containing thermogravimetric analyses raw data on evolved gas analyses experiments (TGA-FTIR and TED-GC-MS)
- TGA_kinetics.zip containing thermogravimetric analyses raw data on decomposition kinetic experiments (ramp-kinetics)
- TGA-FTIR.zip containing Fourier-transform infrared spectroscopy series files for OMNIC
- XRF.zip containing x-ray flourescence data on elemental composition
KW - Adsorption
KW - Aktivkohle
KW - TED-GC/MS
KW - Thermoanalytik
PY - 2020
DO - https://doi.org/10.5281/zenodo.3716316
PB - Zenodo
CY - Geneva
AN - OPUS4-51902
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Transforming Materials Science with ontologies, ELN, and LIMS: Semantic Web Solutions for Digitalization and Data Excellence
N2 - Following the new paradigm of materials development, design and optimization, digitalization is the main goal in materials sciences (MS) which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR (findability, accessibility, interoperability, reusability) principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web Technologies (SWT) are used since they allow for machine-understandable and human-readable knowledge representations needed for data management, retrieval, and (re)use.
The project ‘platform MaterialDigital’ (PMD) is part of an initiative that aims to bring together and support interested parties from both industrial and academic sectors in a sustainable manner in solving digitalization tasks and implementing digital solutions. Therefore, the establishment of a virtual material data space and the systematization of the handling of hierarchical, process-dependent material data are focused. Core points to be dealt with are the development of agreements on data structures and interfaces implemented in distinct software tools and to offer users specific added values in their projects. Furthermore, the platform contributes to a standardized description of data processing methods in materials research. In this respect, selected MSE methods are ontologically represented which are supposed to serve as best practice examples with respect to knowledge representation and the creation of knowledge graphs used for material data.
Accordingly, this presentation shows the efforts taken within the PMD project to store data in accordance with a testing standard compliant ontological representation of a tensile test of metals at room temperature (ISO 6892-1:2019-11). This includes the path from developing an ontology in accordance with the respective standard up to connecting the ontology and data. The semantic connection of the ontology and data leads to interoperability and an enhanced ability of querying. For further enhanced reusability of data and knowledge from synthesis, production, and characterization of materials, the PMD core ontology (PMDco) was developed as mid-level ontology in the field of MSE. The semantic connection of the tensile test ontology (TTO) to the PMDco leads to enhanced expressivity and interoperability.
Moreover, as a best practice example, generation and acquisition of test data semantically connected to the ontology (data mapping) was realized by applying an electronic laboratory notebook (ELN). Corresponding tensile tests were performed by materials science students at university. This enabled a fully digitally integrated experimental procedure that can be transferred to other test series and experiments. In addition to facilitating the acquisition, analysis, processing, and (re)usability of data, this also raises the awareness of students with respect to data structuring and semantic technologies in the sense of education and training. The entire data pipeline is further seamlessly integrable in a laboratory information management system (LIMS). More specifically, the integration of semantic conceptualization and knowledge graphs may become essential parts in LIMS as this would be very beneficial. Therefore, some first approaches of SWT integration in LIMS will also be presented briefly.
T2 - TMS Specialty Congress 2024
CY - Cleveland, OH, USA
DA - 16.06.2024
KW - Semantic Data
KW - Plattform Material Digital
KW - Tensile Test Ontology
KW - Electronic Lab Notebook
KW - Material Life Cycle
PY - 2024
AN - OPUS4-60394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Suárez Ocano, Patricia
T1 - Effect of heat treatment on the hierarchical microstructure and properties of 316L stainless steel produced by Laser Powder Bed Fusion (PBF-LB/M).
N2 - Laser Powder Bed Fusion (PBF-LB/M) of AISI 316L stainless steel has gained popularity due to its exceptional capacity to produce complex geometries and hierarchical microstructures, which can increase the yield strength while maintaining good ductility. Nevertheless, owing to high thermal gradients encountered during the process, the as printed 316L stainless steel often exhibit microstructural heterogeneities and residual stresses, which can limit its performance in demanding environments. Hence, employing heat treatments which balance the reduction of residual stresses while retaining improved static strength may be beneficial in various scenarios and applications. This study investigates the impact of post-processing heat treatments on the microstructure of 316L stainless steel manufactured via PBF-LB/M, along with its correlation with micro-hardness properties. To this end, 6 different heat treatments, i.e., 450 °C for 4h, 700 °C for 1h, 700 °C for 3h, 800 °C for 1h, 800 °C for 3h, and 900 °C for 1h, were applied to different specimens and Vickers hardness measurements (HV1) were performed in all states. At 800 °C, although the cellular structure appears to be retained, there is an observable increase in cellular size. However, while treatments exceeding 900 °C indicate no significant grain growth compared to other conditions, the cellular structure is entirely dissolved, which leads to a reduced Vickers hardness. The effect of the heat treatments on other microstructural features such as grain size and morphology, melt pool boundaries (MPB), crystallographic texture, chemical segregation, dispersoids and phase stability are also discussed in the present work
T2 - 4th Symposium on Materials and Additive Manufacturing
CY - Berlin, Germany
DA - 12.06.2024
KW - Additive manufacturing
KW - Heat treatment
KW - Microstructure
PY - 2024
AN - OPUS4-60304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Adapting FAIR Practices in Materials Science: Digital Representation of Material-Specific Characterization Methods
N2 - Age-hardenable aluminum alloys undergo precise heat treatments to yield nanometer-sized precipitates that increase their strength and durability by hindering the dislocation mobility. Tensile tests provide mechanical properties, while microstructure evaluation relies on transmission electron microscopy (TEM), specifically the use of dark-field TEM images for precise dimensional analysis of the precipitates. However, this manual process is time consuming, skill dependent, and prone to errors and reproducibility issues.
Our primary goal is to digitally represent these processes while adhering to FAIR principles. Ontologies play a critical role in facilitating semantic annotation of (meta)data and form the basis for advanced data management. Publishing raw data, digital workflows, and ontologies ensures reproducibility.
This work introduces innovative solutions to traditional bottlenecks and offers new perspectives on digitalization challenges in materials science. We support advanced data management by leveraging knowledge graphs and foster collaborative and open data ecosystems that potentially revolutionize materials research and discovery.
T2 - TMS - Specialty Congress 2024
CY - Cleveland, Ohio, US
DA - 16.06.2024
KW - FAIR
KW - Research Data Management
KW - Semantic Interoperability
KW - Ontologies
KW - Materials and Processes Data Reusability
PY - 2024
AN - OPUS4-60375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mohr, Gunther
T1 - Development of representative test specimens by thermal history transfer in laser powder bed fusion
N2 - The use of components manufactured by laser powder bed fusion (PBF LB/M) and subjected to fatigue loading is still hampered by the uncertainty about the homogeneity of the process results. Numerous influencing factors including the component’s geometry contribute to the risk of process instability and resulting inhomogeneity of properties. This drastically limits the comparability of different built parts and requires expensive full component testing. The thermal history as the spatiotemporal temperature distribution has been identified as a major cause for flaw formation. Therefore, it can be hypothesized that a similar thermal history between components and test specimens enhances their comparability. Following this assumption, a strategy is developed to transfer the intrinsic preheating temperature as a measure of comparability of thermal histories from a region of interest of a complex component to a simple test specimen. This transfer concept has been successfully proved by the use of FEM-based macroscale thermal simulations, validated by calibrated infrared thermography. An adoption of the specimen manufacturing process by the adjustment of the inter layer times was established to manufacture specimens which are representatives of a specific region of a large-scale component in terms of the thermal history similarity criterion. The concept is schematically illustrated in Figure 1 and was demonstrated using a pressure vessel geometry from the chemical industry.
T2 - 4th Symposium on Materials and Additive Manufacturing
CY - Berlin, Germany
DA - 12.06.2024
KW - Additive manufacturing
KW - Thermal history
KW - Laboratory specimens
KW - In situ monitoring
KW - Representative specimens
PY - 2024
AN - OPUS4-60260
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Ueltzen, Katharina
A1 - George, Janine
T1 - Bonding analysis results for "Chemical ordering and magnetism in face-centered cubic CrCoNi alloy"
N2 - This repository contains the code and data to produce the results of chapter IIIC. Covalent bonding analysis for L12/L10 type configurations of the publication Chemical ordering and magnetism in face-centered cubic CrCoNi alloy by Sheuly Ghosh et al.
KW - Magnetism
KW - Bonding Analysis
KW - Medium Entropy Alloys
PY - 2024
DO - https://doi.org/10.5281/zenodo.11104874
PB - Zenodo
CY - Geneva
AN - OPUS4-59987
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skrotzki, Birgit
T1 - Fatigue Behavior at Elevated Temperature of Alloy EN AW-2618A
N2 - The influence of test temperature and frequency on the fatigue life of the alloy EN AW-2618A (2618A) was characterized. The overaged condition (T61 followed by 1000 h/230 °C) was investigated in load-controlled tests with a stress ratio of R = -1 and two test frequencies (0.2 Hz, 20 Hz) at room temperature and at 230°C, respectively. An increase in the test temperature reduces fatigue life, whereby this effect is more pronounced at lower stress amplitudes. Decreasing the test frequency in tests at high temperatures further reduces the service life.
T2 - ICAA19 International Conference on Aluminum Alloys
CY - Atlanta, GA, USA
DA - 23.06.2024
KW - Aluminium alloy
KW - EN AW 2618A
KW - Fatigue
KW - Overaging
KW - Damage behavior
PY - 2024
AN - OPUS4-60426
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
A1 - Hanke, Thomas
A1 - Chen, Yue
T1 - Brinell test ontology (BTO)
N2 - Brinell Test Ontology (BTO) has developed for representing the Brinell testing process, testing equipment requirements, test pieces charactristics, and related testing parameters and their measurement procedure according to DIN EN ISO 6506-1 standard.
Versions info:
V2 developed using BFO+CCO top-level ontologies.
V3 developed using EMMO+CHAMEO top-level ontologies.
V4 developed using PROVO+PMDco top-level ontologies.
V5 developed using BFO+IOF top-level ontologies.
Repositories:
GitLab: https://gitlab.com/kupferdigital/process-graphs/brinell-hardness-test
GitHub: https://github.com/HosseinBeygiNasrabadi/Brinell-Test-Ontology-BTO-
MatPortal: https://matportal.org/ontologies/BTO
IndustryPortal: https://industryportal.enit.fr/ontologies/BTO
KW - Ontology
KW - Knowledge graph
KW - Data mapping
KW - Brinell hardness
KW - FAIR data
PY - 2024
UR - https://gitlab.com/kupferdigital/process-graphs/brinell-hardness-test
UR - https://github.com/HosseinBeygiNasrabadi/Brinell-Test-Ontology-BTO-
UR - https://matportal.org/ontologies/BTO
UR - https://industryportal.enit.fr/ontologies/BTO
PB - GitLab
CY - San Francisco, CA, USA
AN - OPUS4-60543
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Vickers test ontology (VTO)
N2 - Vickers Test Ontology (VTO) has developed for representing the Vickers testing process, testing equipment requirements, test pieces charactristics, and related testing parameters and their measurement procedure according to DIN EN ISO 6507-1 standard.
Versions info:
V2 developed using BFO+CCO top-level ontologies.
Repositories:
GitLab: https://gitlab.com/kupferdigital/process-graphs/vickers-hardness-test
GitHub: https://github.com/HosseinBeygiNasrabadi/Vickers-Test-Ontology-VTO-
MatPortal: https://matportal.org/ontologies/VTO
IndustryPortal: https://industryportal.enit.fr/ontologies/VTO
KW - Ontology
KW - Knowledge graph
KW - Data mapping
KW - Vickers hardness
KW - FAIR data.
PY - 2024
UR - https://gitlab.com/kupferdigital/process-graphs/vickers-hardness-test
UR - https://github.com/HosseinBeygiNasrabadi/Vickers-Test-Ontology-VTO-
UR - https://matportal.org/ontologies/VTO
UR - https://industryportal.enit.fr/ontologies/VTO
PB - GitLab
CY - San Francisco, CA, USA
AN - OPUS4-60544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-Throughput Approaches for Materials Understanding and Design
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale. The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials. Furthermore, the general trend toward automation in computational materials science and some of our recent contributions will be discussed.
T2 - International Symposium on Computational Structure Prediction and Advanced Materials
CY - Louvain-la-Neuve, Belgium
DA - 22.08.2024
KW - Automation
KW - High-throughput
KW - Magnetism
KW - Phonons
KW - Machine learning
KW - Chemically complex materials
PY - 2024
AN - OPUS4-60870
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven approaches for materials understanding and design
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale. The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials. Furthermore, the general trend toward automation in computational materials science and some of our recent contributions will be discussed.
T2 - Machine Learning of First Principles Observables
CY - Berlin, Germany
DA - 08.07.2024
KW - Automation
KW - Bonding Analysis
KW - Machine Learned Potentials
PY - 2024
AN - OPUS4-60660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Crafting High-Quality, Reliable, and FAIR Data: From Metadata, Schema and Ontologies to Data Management and Knowledge Transfer
N2 - Following the new paradigm of materials development, design and optimization, digitalization is the main goal in materials sciences (MS) which imposes a huge challenge. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR (findability, accessibility, interoperability, reusability) principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web Technologies (SWT) are used since they allow for machine-actionable and human-readable knowledge representations needed for data management, retrieval, and (re)use.
In this respect, the motivation for digital transformation in materials sciences stemming from the need to handle the ever-increasing volume and complexity of data will be elaborated on. By embracing digital tools and methodologies, researchers can enhance the efficiency, accuracy, and reproducibility of their work. The benefits of digital transformation in materials sciences are manifold, including improved data management, enhanced collaboration, and accelerated innovation. Being a core component of this transformation, ensuring data reliability and reproducibility is critical for the advancement of the field, enabling researchers to build on each other's work with confidence. Implementing FAIR data principles facilitates this by making data more accessible and usable across different platforms and studies. Furthermore, Semantic Web technologies (SWT) and ontologies play a crucial role in achieving these goals. Ontologies, typically consisting of the T-Box (terminological component) and A-Box (assertional component), provide a structured framework for representing knowledge. This presentation will outline the path of ontology creation and the formal transformation procedure, highlighting the various ontology levels that organize data into meaningful hierarchies.
Real-world use cases presented, such as the Tensile Test Ontology (TTO) and the Orowan Demonstrator, illustrate the practical applications of these technologies. These examples will demonstrate how ontologies can be leveraged to standardize data and facilitate interoperability between different systems and research groups. Finally, in this presentation, Ontopanel is introduced, a tool designed to aid in the creation and management of ontologies. Ontopanel simplifies the process of developing and maintaining ontologies, making it accessible to researchers and practitioners in the field. By integrating these technologies and principles, the materials science community can move towards a more digital, interconnected, and efficient future making the knowledge and education on these topics very valuable.
T2 - MaRDA MaRCN FAIR Train Workshop
CY - Washington, DC, USA
DA - 29.07.2024
KW - FAIR
KW - Metadata
KW - Digitalization
KW - Data Interoperability
KW - Ontology
KW - Education
KW - Workshop
PY - 2024
AN - OPUS4-60720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
T1 - Numerical Investigations of Porosity Mitigation in High-Power Laser Beam Welding with an External Magnetic Field
N2 - The application of an external magnetic field has been found to significantly mitigate the porosity ratio in laser beam welded joints of AlMg3 aluminum alloy. To investigate the suppression mechanism, a 3D transient multi-physics coupled numerical model of laser beam welding (LBW), including laser propagation, laser-material interaction, and magnetohydrodynamic effects, has been developed to calculate the keyhole dynamics and weld pool behaviors during the welding process. The induced time-averaged Lorenz force is directed downward. Under the effects of the external magnetic field, the fluid flow pattern and the weld pool profile are both affected. The keyhole geometry reconstruction algorithm is proposed to calculate the keyhole diameter and its fluctuation, which is used to evaluate the keyhole stability. The results indicate that the oscillating magnetic field does not affect keyhole stability obviously in the LBW of aluminum alloy. Moreover, an electromagnetic expulsive force is induced on the bubble because of the time-averaged downward Lorentz force. This electromagnetic expulsive force can accelerate the bubble escape speed considerably. An analytical model is developed for investigating the bubble escape window, which shows that the bubble escape window is expanded by 45% under the effect of the external magnetic field. The calculated results based on the developed model agree well with the experimental results.
T2 - 77th IIW Annual Assembly and International Conference
CY - Rhodes, Greece
DA - 07.07.2024
KW - Numerical simulation
KW - Deep penetration laser beam welding; Keyhole stability
KW - Porosity defects
KW - Magnetic field
PY - 2024
AN - OPUS4-60667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Fedelich, Bernard
A1 - Jokisch, Torsten
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - High Temperature Fatigue Crack Growth in Nickel-Based Alloys Refurbished by Additive Manufacturing
N2 - Hybrid additive manufacturing plays a crucial role in the restoration of gas turbine blades, where, e.g., the damaged blade tip is reconstructed by the additive manufacturing process on the existing blade made of a parent nickel-based alloy. However, inherent process-related defects in additively manufactured material, along with the interface created between the additively manufactured and the cast base material, impact the fatigue crack growth behavior in bi-material components. This study investigates the fatigue crack growth behavior in bi-material specimens of nickel-based alloys, specifically, additively manufactured STAL15 and cast alloy 247DS. The tests were conducted at 950 °C with stress ratios of 0.1 and −1. Metallographic and fractographic investigations were carried out to understand crack growth mechanisms. The results revealed significant retardation in crack growth at the interface. This study highlights the potential contributions of residual stresses and microstructural differences to the observed crack growth retardation phenomenon, along with the conclusion from an earlier study on the effect of yield strength mismatch on crack growth behavior at a perpendicular interface in bi-material specimens.
T2 - Superalloys 2024 Conference
CY - Champion, Pennsylvania, USA
DA - 08.09.2024
KW - Fatigue crack growth
KW - Bi-material structure
KW - Additive manufacturing
KW - Nickel-based alloys
PY - 2024
SN - 978-3-031-63937-1
DO - https://doi.org/10.1007/978-3-031-63937-1_92
SN - 2367-1181
SN - 2367-1696
VL - 15th
SP - 994
EP - 1001
PB - Springer
CY - Cham
AN - OPUS4-60907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-throughput Approaches for Materials Understanding and Design
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties.[1] Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available.[2,3] Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale.[3,4] The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials.[5,6] Furthermore, the general trend toward automation in computational materials science and some of our recent contributions will be discussed.[7–10]
T2 - International Materials Science and Engineering Congress - MSE 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Automation
KW - High-throughput
KW - Chemically Complex Materials
KW - Thermal Properties
KW - Phonons
KW - Bonding Analysis
PY - 2024
AN - OPUS4-61118
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - New opportunities through an efficient combination of machine learning and high-throughput computing
N2 - The underlying data is crucial for machine learning (ML) tasks.[1] Ab initio data is often used as a target (occasionally as features[2]). High-throughput calculations and automation make it possible to generate such data as efficiently as possible and with uniform standards.[3,4] The high-throughput data of the Materials Project has recently been used to train new foundation interatomic potentials[5].
Several high-throughput frameworks have been developed in recent years. This presentation will introduce the atomate2/jobflow[3,4] framework that is used and developed by researchers around the Materials Project. In the future, it will be used to generate the data for the Materials Project.
Atomate2 allows both the use of DFT and ML potentials within one framework. Building upon this framework, we have developed a package with the possibility to train and benchmark ML potentials automatically. Currently, the package can be used to train ML interatomic potentials sufficient to predict harmonic phononic properties of materials. Typical foundation models in this area now achieve acceptable results but are still far from routinely replacing DFT.[5,6] Building on the promising results from the ref where we explored data generation strategies for accurate phononic properties[7], we will present new fully automated workflows for training and benchmarking ML interatomic potentials with force predictions that are accurate enough to compute harmonic phonons in very good agreement with DFT for different crystal structures of the same composition.
T2 - GAP/(M)ACE Developers & Users Meeting 2024
CY - Berlin, Germany
DA - 17.09.2024
KW - Automation
KW - Workflows
KW - Machine Learned Interatomic Potentials
KW - Thermal Properties
KW - Bonding Analysis
KW - Chemically Complex Materials
PY - 2024
AN - OPUS4-61099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
T1 - High temperature fatigue crack growth in nickel-based alloys joined by brazing and additive manufacturing
N2 - Nickel-based alloys have been widely used for gas turbine blades owing to their excellent mechanical properties and corrosion resistance at high temperatures. The operating temperatures of modern gas turbines have been increased in pursuit of increased thermal efficiency. Turbine blades are exposed to these high temperatures combined with mechanical stresses, resulting in material damage through creep, fatigue, and other mechanisms. These turbine blades must be regularly inspected and replaced as needed, to prevent the loss of efficiency, breakdown, and catastrophic failure. Repair of the damaged turbine blades is often a more practical and cost-effective option than replacement, as replacement is associated with high costs and loss of material resources. To this end, state-of-the-art repair technologies including different additive manufacturing and brazing processes are considered to ensure efficient repair and optimum properties of repaired components.
In any repaired part, materials property-mismatches and/or inner defects may facilitate the crack initiation and propagation and thus reduce the number of load cycles to failure. Therefore, a fundamental understanding of the fatigue crack growth and fracture mechanisms in joining zones is required to enable the prediction of the remaining life of repaired components and to further improve and adapt the repair technologies.
Fatigue crack growth experiments have been conducted on SEN (Single Edge Notch) specimens joined via brazing, and pre-sintered Preform (PSP) and multi-materials (casted/printed) specimens layered via additive manufacturing (AM). The experiments were performed at 950 °C and various stress ratios. The crack growth was measured using DCPD (Direct Current Potential Drop) method. The stress intensity factors for joined SEN specimens were calculated using the finite element method and then used to derive the fatigue crack growth curves. Metallographic and fractographic analyses were conducted to get insight into the fracture mechanism.
Results show that the experimental technique for fatigue crack growth was successfully adapted and applied for testing joined specimens. Furthermore, the initial tests indicate that the investigated braze filler material provides a lower resistance to crack growth, and bonding defects cause a crack to deviate to the interface of the base material and joining zone. In AM-sandwich specimens, the crack growth rates are significantly reduced when the crack reaches the interface of printed material and casted material. The obtained crack growth data can be used to calibrate a crack growth model, which will further be utilized to predict the remaining life of repaired components.
T2 - DGM Arbeitskreis Mechanisches Werkstoffverhalten bei hoher Temperatur im FachausschussWerkstoffverhalten unter mechanischer Beanspruchung
CY - Munich, Germany
DA - 10.10.2023
KW - Fatigue crack growth
KW - Joined nickel-based alloys
PY - 2023
AN - OPUS4-60908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
T1 - High temperature fatigue crack growth in nickel-based alloys joined by brazing and additive manufacturing
N2 - Nickel-based alloys have been widely used for gas turbine blades owing to their excellent mechanical properties and corrosion resistance at high temperatures. The operating temperatures of modern gas turbines have been increased in pursuit of increased thermal efficiency. Turbine blades are exposed to these high temperatures combined with mechanical stresses, resulting in material damage through creep, fatigue, and other mechanisms. These turbine blades must be regularly inspected and replaced as needed, to prevent the loss of efficiency, breakdown, and catastrophic failure. Repair of the damaged turbine blades is often a more practical and cost-effective option than replacement, as replacement is associated with high costs and loss of material resources. To this end, state-of-the-art repair technologies including different additive manufacturing and brazing processes are considered to ensure efficient repair and optimum properties of repaired components.
In any repaired part, materials property-mismatches and/or inner defects may facilitate the crack initiation and propagation and thus reduce the number of load cycles to failure. Therefore, a fundamental understanding of the fatigue crack growth and fracture mechanisms in joining zones is required to enable the prediction of the remaining life of repaired components and to further improve and adapt the repair technologies.
Fatigue crack growth experiments have been conducted on SEN (Single Edge Notch) specimens joined via brazing, and pre-sintered Preform (PSP) and multi-materials (casted/printed) specimens layered via additive manufacturing (AM). The experiments were performed at 950 °C and various stress ratios. The crack growth was measured using DCPD (Direct Current Potential Drop) method. The stress intensity factors for joined SEN specimens were calculated using the finite element method and then used to derive the fatigue crack growth curves. Metallographic and fractographic analyses were conducted to get insight into the fracture mechanism.
Results show that the experimental technique for fatigue crack growth was successfully adapted and applied for testing joined specimens. Furthermore, the initial tests indicate that the investigated braze filler material provides a lower resistance to crack growth, and bonding defects cause a crack to deviate to the interface of the base material and joining zone. In AM-sandwich specimens, the crack growth rates are significantly reduced when the crack reaches the interface of printed material and casted material. The obtained crack growth data can be used to calibrate a crack growth model, which will further be utilized to predict the remaining life of repaired components.
T2 - Fatigue 2024 Conference
CY - Cambridge, UK
DA - 19.06.2024
KW - Fatigue crack growth
KW - Joined nickel-based alloys
PY - 2024
AN - OPUS4-60893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
T1 - High Temperature Fatigue Crack Growth in Nickel-Based Alloys Refurbished by Additive Manufacturing and Brazing
N2 - Hybrid additive manufacturing plays a crucial role in the restoration of gas turbine blades, where e.g., the damaged blade tip is reconstructed by the additive manufacturing process on the existing blade made of a parent nickel-based alloy. However, inherent process-related defects in additively manufactured material, along with the interface created between the additively manufactured and the cast base material, impact the fatigue crack growth behavior in bi-material components. This study investigates the fatigue crack growth behavior in bi-material specimens of nickel-based alloys, specifically, additively manufactured STAL15 and cast alloy 247DS. The tests were conducted at 950 °C with stress ratios of 0.1 and -1. Metallographic and fractographic investigations were carried out to understand crack growth mechanisms. The results revealed significant retardation in crack growth at the interface. This study highlights the potential contributions of residual stresses and microstructural differences to the observed crack growth retardation phenomenon, along with the conclusion from an earlier study on the effect of yield strength mismatch on crack growth behavior at a perpendicular interface in bi-material specimens.
T2 - Superalloys 2024 Conference
CY - Champion, PA, USA
DA - 08.09.2024
KW - Fatigue crack growth
KW - Bi-material structure
KW - Nickel-based alloys
KW - Additive Manufacturing
KW - Brazing
PY - 2024
AN - OPUS4-61047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-Driven Approaches for Materials Understanding and Design
N2 - Data-Driven Approaches for Materials Understanding and Design
Analyzing the crystal structure (including coordination environments, bond distances, and angles) and chemical bonding are standardly used in chemistry to understand material properties. In this talk, I will show how we can use this information in machine learning of material properties. For this purpose, I will present our software tools ChemEnv[1] for analyzing coordination environments and for automation of orbital-based bonding analysis with LOBSTER[2] (LobsterPy[3] and density-functional theory workflows in atomate2[4]). Enabled by these software tools, we have built interpretable machine-learned models for magnetic and vibrational properties that allow us to test and further develop intuitive rules.[5,6]
T2 - Institutskolloqium Institut für Anorganische Chemie und Kristallographie
CY - Leipzig, Germany
DA - 23.10.2024
KW - Automation
KW - Bonding Analysis
KW - Materials Design
KW - Chemically Complex Materials
KW - Phonons
KW - Thermal Properties
KW - Synthesizability
KW - Machine Learning
PY - 2024
AN - OPUS4-61445
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-throughput approaches for materials understanding and design
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties.[1] Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available.[2,3] Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale.[3,4] The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials.[5,6] Furthermore, the general trend toward automation in computational materials science and some of our recent contributions will be discussed.[7–11]
T2 - TCO 2024 - Transparent Conductive Oxides, Fundamentals and Applications
CY - Leipzig, Germany
DA - 23.09.2024
KW - Automation
KW - Materials discovery
KW - Machine Learned Interatomic Potentials
KW - Workflows
KW - Chemically Complex Materials
KW - Bonding Analysis
PY - 2024
AN - OPUS4-61153
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Digital representation of materials testing data for semantic web analytics: Tensile stress relaxation testing use case
N2 - This study aims to represent an approach for transferring the materials testing datasets to the digital schema that meets the prerequisites of the semantic web. As a use case, the tensile stress relaxation testing method was evaluated and the testing datasets for several copper alloys were prepared. The tensile stress relaxation testing ontology (TSRTO) was modeled following the test standard requirements and by utilizing the appropriate upper-level ontologies. Eventually, mapping the testing datasets into the knowledge graph and converting the data-mapped graphs to the machine-readable Resource Description Framework (RDF) schema led to the preparation of the digital version of testing data which can be efficiently queried on the web.
KW - Digitalization
KW - Tensile stress relaxation
KW - Ontology
KW - Mechanical testing
KW - Semantic web
PY - 2024
DO - https://doi.org/10.4028/p-xSmHN2
VL - 987
SP - 47
EP - 52
PB - Trans Tech Publications Ltd
CY - Switzerland
AN - OPUS4-61152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bayerlein, Bernd
T1 - Digital Transformation in Materials Science:Insights from Platform MaterialDigital
N2 - In the digital transformation of materials science and engineering, existing processes are being closely examined to optimize and extend them using technologies such as the Semantic Web, while adhering to the FAIR principles. The challenge is to identify and adapt these technologies to significantly improve daily operations, covering the entire cycle of data generation, collection, storage to its processing and use. This presentation presents different approaches developed within the Platform MaterialDigital (PMD) and related initiatives, each addressing specific challenges of digitalization and demonstrating their benefits. These will be illustrated by a case study on age-hardenable aluminium alloys in different aging states, based on a comprehensive dataset of microstructural and mechanical properties.
In this context, ontologies are essential for organizing data into interoperable semantic structures, thereby enabling the representation of concepts and their relationships. The PMD Core Ontology (PMDco) serves as a higher semantic layer that connects domain-specific ontologies [1]. The PMDco provides MSE-specific bridging concepts that enhance data mapping and integration capabilities. This approach facilitates the linking of results from natural language processing of a corpus of microscopy abstracts, which supported the development of a microscopy ontology. In addition, the presentation highlights how modular, digital workflows can improve the reproducibility of transmission electron microscopy image processing and analysis [2]. It also shows how freely available mechanical and microstructural datasets are semantically integrated and made searchable through PMDco, facilitating correlation analysis [3]. Looking ahead, the integration of these components has the potential to advance and sustain MSE practices.
T2 - MSE Congress 2024 - Materials Science and Engineering
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Semantic Interoperability
KW - FAIR data management
KW - Digtial Representation
PY - 2024
AN - OPUS4-61137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Seamless Science: Navigating Daily Lab Life through Semantic Data Integration, Electronic Lab Notebooks, and Knowledge Graphs in the Era of MSE Digitalization
N2 - The field of materials science and engineering (MSE) is currently experiencing a significant paradigm shift towards enhanced digitalization which imposes a huge challenge on researchers, scientists, engineers, and technicians. In this respect, the quality assurance of processes and output data as well as the interoperability between applications following FAIR principles are to be ensured. For storage, processing, and querying of data in contextualized form, Semantic Web technologies (SWT) are used as they allow for machine-actionable and human-readable knowledge representations needed for data management, retrieval, and (re)use.
The collaborative project ‘platform MaterialDigital’ (PMD) aims to solve digitalization tasks and implement digital solutions in the field of MSE in a prototypical manner. Therefore, the establishment of a virtual material data space and the systematization of the handling of hierarchical, process-dependent material data are focused. In this respect, selected MSE methods are semantically represented which are supposed to serve as best practice examples with respect to knowledge representation and the creation of knowledge graphs used for material data.
Accordingly, this presentation shows the efforts taken within PMD to store data in accordance with a testing standard compliant semantic representation of a tensile test of metals at room temperature (ISO 6892-1:2019-11). A semantic link of the corresponding tensile test ontology (TTO) and data leads to enhanced data useability and interoperability. The PMD core ontology (PMDco), developed in PMD and used as mid-level ontology in TTO, is also presented briefly. Moreover, as a best practice example, the acquisition of tensile test data with subsequent generation of knowledge graph data by semantic interconnection using TTO was realized by applying an electronic laboratory notebook (ELN). Corresponding tensile tests were performed by undergraduate MSE students at the Technical University of Darmstadt. The resulting data pipeline, also illustrated in the presentation, enabled a fully-fledged digitally integrated experimental procedure, the approach of which may be transferred to other test series and experiments. In addition to facilitating the acquisition, analysis, processing, and (re)usability of data, this also raises the awareness of students with respect to data structuring and semantic technologies in terms of education and training.
T2 - Materials Science and Engineering Congress 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - FAIR
KW - Plattform Material Digital
KW - Digitalization
KW - Data Interoperability
KW - Electronic Lab Notebook
KW - Education
PY - 2024
AN - OPUS4-61138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beygi Nasrabadi, Hossein
T1 - Platform MaterialDigital (PMD) approach for the integration and management of FAIR low cycle fatigue (LCF) testing data
N2 - This study represents the generation and storage of findable, accessible, interoperable, and reusable (FAIR) fatigue testing data by utilizing the Platform MaterialDigital (PMD) core ontology (PMDco) as well as some containerized PMD-server applications. Based on the specifications of the ISO 12106:2017-03 standard [1] and the acquired test reports of the mechanical testing facility, a highly comprehensive process graph of the fatigue testing procedure was created. Consequently, the PROV Ontology (PROVO) and PMDco [2] were used as upper-level ontologies to model the fatigue testing ontology (FTO). A part of the FTO classes hierarchy is shown in Fig. 1, where all the concepts of test procedure, test apparatus, test piece, and test properties were respectively located in the appropriate hierarchies of pmd:Process (prov:Activity), pmd:ProcessingNode (prov:Agent), pmd:Object (prov:Entity), and pmd:ValueObject (prov:Entity) classes. FTO is publicly available via the GitLab repository [3]. Reusing these upper-level ontologies and materials testing standards not only improves FTO's compatibility with other ontologies but also ensures its acceptance and deployment in industry [4]. The fatigue testing process graph has also been designed in such a manner that it allows for the entire mapping of testing metadata. In this respect, low-cycle fatigue (LCF) experiments were carried out on several cast copper alloys at various strain ratios, and the resulting CSV test report files were stored in a public repository [5]. Eventually, the processes of mapping the experimental test data into the fatigue process graph, converting the RDF data, storage of the triples in a triple store, and SPARQL query from the obtained triples are evaluated by different PMD-based tools like PMD OntoDocker [6].
T2 - MSE2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Digitalization
KW - FAIR
KW - Low cycle fatigue
PY - 2024
AN - OPUS4-61151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beygi Nasrabadi, Hossein
T1 - Nb and Cr coating the CuNi3SiCr powders for low-power laser-based powder bed fusion processing of copper alloys
N2 - The laser-based powder bed fusion (PBF-LB/M) processing of high-density copper components is mainly performed with high laser powers due to the low laser absorption of copper powders [1-2]. Metal coating the copper particles has been investigated in this research as an approach for increasing the laser absorption of the feedstock and processing of highly dense copper alloys with low-power lasers. CuNi3SiCr powders were coated with the thin and uniform metallic shells of Nb (60 ± 10 nm) using a rotating Direct Current Magnetron Sputtering Physical Vapor Deposition (DCMS-PVD) reactor. Using such metal-coated particles, copper parts of 98.14% relative density were printed with the PBF-LB/M parameters of 200 W laser powers, 800 mm/s scanning speed, 55 µm hatch distance, and 25 µm layer thickness. The X-ray computed tomography (XCT), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) investigations show that partial oxidation of Nb-coated particles is responsible for the development of lack-of-fusion holes between the printed layers. An approach based on the nanoindentation and electron backscattered diffraction (EBSD) measurements was utilized to evaluate the correlation between the crystallographic orientations and mechanical properties of the produced samples. In this approach, arrays of indentations (Fig. 1a) were applied on four planes of the samples trimmed in different directions. The EBSD images of these indentation regions reveal the location of each indent in colored grains of different orientations. Here, a microstructure with columnar grains and a high texture intensity of 9.2 has been observed in the plane perpendicular to the building direction. This plane comprises a mixture of red-, green-, and blue-colored grains, while the measured average hardness (H) and indentation modulus (Er) were increased from red grains to green and blue ones, respectively (Fig. 1b). Eventually, the nanoindentation load-displacement curves of [001], [101], and [111] grains (Fig. 1c) were utilized for modeling the elastoplastic features of the produced samples.
T2 - MSE2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Coating
KW - Laser-based powder bed fusion processing
KW - Copper
PY - 2024
AN - OPUS4-61149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Han, Ying
T1 - The influence of overaging on high cycle fatigue of Al-alloy EN AW-2618A
N2 - The aluminum alloy EN AW-2618A (2618A) is a precipitation hardened high strength alloy that is used at elevated temperatures in the transportation and aerospace industries. The main alloying elements are Cu and Mg which form a coarse intermetallic primary phase (Al9FeNi) of several µm in size. This phase is responsible for the long-term high temperature creep resistance. The basic strength is due to the precipitation of the so-called S-phase (Al2CuMg) of nm-size, which is known to coarsen during service at elevated temperatures.
Previous projects have characterized the alloy in terms of strength, low cycle fatigue (LCF) and creep behavior, especially at high temperatures (up to 190 °C). Both the T61 and overaged states were used. In addition, the microstructural changes associated with overaging were extensively studied and quantified microscopically [1-2].
However, data on high cycle fatigue (HCF) is still very limited. Therefore, this study [3] investigates the influence of overaging on HCF of 2618A. For this purpose, axial HCF tests were performed at room temperature on two overaged states which are aged for 10 h and 1000 h at 230 °C. Electron microscopy was used to characterize the coarsening of the S-phase from the two overaged states. Fractographic studies were also performed to investigate the influence of the primary phase on the fatigue life.
T2 - MSE 2024
CY - Darmstadt, Germany
DA - 24.09.2024
KW - Fatigue
KW - Aluminum alloy
KW - EN AW-2618A
PY - 2024
AN - OPUS4-61188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Czichos, Horst
A1 - Skrotzki, Birgit
ED - Hennecke, Manfred
ED - Skrotzki, Birgit
T1 - Anforderungen, Eigenschaften und Verhalten von Werkstoffen
N2 - Die Eigenschaften verschiedener Werkstoffe werden behandelt und typische Werkstoffkennwerte angegeben. Es werden Arten der Beanspruchung von Bauteilen und Werkstoffen vorgestellt, die diese in technischen Anwendungen unterworfen sind. Im Betrieb von Bauteilen kann Materialschädigung und unter Umständen auch Versagen eintreten. Mögliche Mechanismen und Ursachen werden erläutert und Einblicke in die Methodik der Schadensanalyse gegeben.
KW - Beanspruchung
KW - Werkstoffkennwerte
KW - Mechanische Eigenschaften
KW - Thermophysikalische Eigenschaften
KW - Schadenskunde
KW - Alterung
KW - Bruch
KW - Korrosion
KW - Tribologie
KW - Werkstoffauswahl
PY - 2020
DO - https://doi.org/10.1007/978-3-662-57492-8_29-1
SP - 1
EP - 45
PB - Springer-Verlag GmbH Deutschland
AN - OPUS4-51286
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
A1 - Mishurova, Tatiana
A1 - Serrano-Munoz, Itziar
A1 - Ulbricht, Alexander
A1 - Fritsch, Tobias
A1 - Sprengel, Maximilian
A1 - Evans, Alexander
A1 - Kromm, Arne
A1 - Madia, Mauro
ED - Bruno, Giovanni
T1 - A Critical Discussion on the Diffraction-Based Experimental Determination of Residual Stress in AM Parts
N2 - As opposed to reviewing results on experimental determination of residual stress by diffraction, this paper discusses the open issues when dealing with residual stress determination in additive manufactured parts, in particular those manufactured with laser powder bed fusion techniques. Three points are addressed in detail: (a) the proper determination of the strain-free reference d0, (b) the problem of the determination of the principal axes, and (c) the use of the correct diffraction elastic constants. It is shown that all methods to determine the strain-free reference d0 suffer from caveats, and care must be taken in evaluating the most suitable for the problem being tackled. In addition, it is shown that, in some systems, the principal axes do correspond to the geometrical axes of the specimen, but this needs to be systematically checked, especially in the case of uni- or bidirectional hatching strategies. Finally, the need to experimentally determine the proper diffraction elastic constants is underlined, especially in the case of strongly textured specimens, which again depends on the deposition strategy.
T2 - ASTM ICAM 2020 – ASTM International Conference on Additive Manufacturing
CY - Online meeting
DA - 16.11.2020
KW - Additive Manufacturing
KW - Diffraction
KW - Residual Stress
PY - 2020
DO - https://doi.org/10.1520/STP163120190148
VL - STP1631
SP - 122
EP - 138
PB - ASTM International
CY - USA
AN - OPUS4-51347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, M.
A1 - Elsner, B.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Geometric distortion-compensation via transient numerical simulation for directed energy deposition additive manufacturing
N2 - Components distort during directed energy deposition (DED) additive manufacturing (AM) due to the repeated localised heating. Changing the geometry in such a way that distortion causes it to assume the desired shape – a technique called distortion-compensation – is a promising method to reach geometrically accurate parts. Transient numerical simulation can be used to generate the compensated geometries and severely reduce the amount of necessary experimental trials. This publication demonstrates the simulation-based generation of a distortioncompensated DED build for an industrial-scale component. A transient thermo-mechanical approach is extended for large parts and the accuracy is demonstrated against 3d-scans. The calculated distortions are inverted to derive the compensated geometry and the distortions after a single compensation iteration are reduced by over 65%.
KW - DED
KW - Welding simulation
KW - Dimensional accuracy
KW - Additive manufacturing
KW - Laser metal deposition
KW - LMD
PY - 2020
DO - https://doi.org/10.1080/13621718.2020.1743927
SP - 1
EP - 8
PB - Taylor & Francis
AN - OPUS4-50877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Raute, J.
A1 - Jokisch, T.
A1 - Marko, A.
A1 - Rethmeier, Michael
T1 - Untersuchung zum Elektronenstrahlschweißen heißrissgefährdeter Nickelbasis-Superlegierungen mittels statistischer Versuchsplanung
N2 - Nickelbasis-Superlegierungen sind seit vielen Jahren in unterschiedlichen Industrieanwendungen im Einsatz. Aufgrund der großen Heißrissneigung ist das Schweißen dieser Werkstoffe jedoch bei einer Vielzahl von Legierungen problematisch. Neue Arbeiten auf dem Gebiet zeigen, dass entgegen den gängigen Theorien auch reduzierte Schweißgeschwindigkeiten eine Tendenz zur Verringerung der Rissneigung aufweisen. Bisher existieren jedoch kaum Erkenntnisse zum Prozessverhalten in diesem Parameterbereich. In dieser Arbeit wird daher der Einfluss der relevanten Prozessparameter beim Elektronenstrahlschweißen (EBW) auf die Nahtgestalt im Bereich geringer Vorschubgeschwindigkeiten untersucht. Auf Grundlage der gewonnenen Erkenntnisse soll ein Ansatz zum rissfreien Fügen von komplexen Nickelbasis-Superlegierung gebildet werden. Die praktische Umsetzbarkeit wird abschließend anhand einiger Probeschweißungen an einem besonders heißrissgefährdeten Werkstoff demonstriert. Um fehlerfreie Verbindungen zu ermöglichen, wurden zunächst die relevanten Parameter für die Einstellung von Nahtbreite, Einschweißtiefe, Aspektverhältnis und Nahtfläche anhand einer Versuchsreihe mit 17 Blindschweißungen auf einer 12 mm dicken Platte aus Inconel 718 bestimmt. Die genaue Beschreibung des Einflusses der als signifikant identifizierten Faktoren erfolgte über die Anwendung einer Regressions- und Varianzanalyse. Die Ergebnisse zeigen, dass die Einschweißtiefe, die Nahtbreite, das Aspektverhältnis sowie die Nahtfläche vorrangig über den Strahlstrom, die Fokuslage sowie den Vorschub beeinflusst werden können. Auf Basis der gebildeten statistischen Modelle erfolgte die Vorhersage geeigneter Parameter für eine finale Versuchsreihe. Die abschließenden Demonstratorschweißungen wurden exemplarisch an einer Nickelbasis-Gusslegierung mit besonders hohem Ausscheidungsphasenanteil durchgeführt. Hierfür wurden Schweißungen im I- Stoß an 6,5 mm und 10 mm dicken Blechen ausgeführt. Trotz der mangelnden Schweißeignung und dem hohen Anteil an Ausscheidungsphase des Werkstoffes, zeigten sich nach Optimierung der Prozessparameter keine Heißrisse mehr.
T2 - DVS Congress 2020
CY - Online meeting
DA - 14.09.2020
KW - Heißrisse
KW - Nickelbasis-Superlegierungen
KW - Elektonenstrahlschweißen
KW - Alloy 247
PY - 2020
SN - 978-3-96144-098-6
VL - 365
SP - 17
EP - 22
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-51320
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
T1 - In-situ Prozessüberwachung beim Laser-Pulver-Auftragschweißen (LPA) mittels Thermographie, optischer Emissionsspektroskopie (OES) und Schallemission (AE)
N2 - In diesem Vortrag wird ein Überblick über die in-situ Messverfahren gegeben, die im Rahmen des Projektes ProMoAM an der LPA- Anlage eingesetzt wurden. Im Speziellen sind das die Thermographie, die optische Emissionsspektroskopie (OES) und die Akustische Emission (AE).
T2 - 41. Assistentenseminar der WGF e.V.
CY - Online meeting
DA - 02.09.2020
KW - Schallemission
KW - Laser-Pulver-Auftragschweißen
KW - Thermographie
KW - Optische Emissionsspektroskopie
PY - 2020
AN - OPUS4-51273
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holzer, Marco
A1 - Waurischk, Tina
A1 - George, Janine
A1 - Maaß, Robert
A1 - Müller, Ralf
T1 - Silicate glass fracture surface energy calculated from crystal structure and bond-energy data
N2 - We present a novel method to predict the fracture surface energy, γ, of isochemically crystallizing silicate glasses using readily available crystallographic structure data of their crystalline counterpart and tabled diatomic chemical bond energies, D0. The method assumes that γ equals the fracture surface energy of the most likely cleavage plane of the crystal. Calculated values were in excellent agreement with those calculated from glass density, network connectivity and D0 data in earlier work. This finding demonstrates a remarkable equivalence between crystal cleavage planes and glass fracture surfaces.
KW - Glass
KW - Fracture surface energy
KW - Toughness
KW - Modeling
KW - Mechanical properties
PY - 2023
DO - https://doi.org/10.1016/j.jnoncrysol.2023.122679
SN - 0022-3093
VL - 622
SP - 1
EP - 6
PB - Elsevier B.V.
AN - OPUS4-58767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical study on the formation of a bulging region in partial penetration laser beam welding
N2 - A transient three-dimensional thermo-fluid dynamics numerical model was developed to study the formation of a bulging region in partial penetration laser beam welding. The model accounts for the coupling between the fluid flow, the heat transfer, and the keyhole dynamics by considering the effects of multiple reflections and Fresnel absorption of the laser beam in the keyhole, the phase transitions during melting and evaporating, the thermo-capillary convection, the natural convection, and the phase-specific and temperature-dependent material properties up to the evaporation temperature. The validity of the model was backed up by experimentally obtained data, including the drilling time, the weld pool length, the local temperature history outside the weld pool, the process efficiency, and a range of metallographic crosssections.
The model was applied for the cases of partial penetration laser beam welding of 8 mm and 12 mm thick unalloyed steel sheets. The obtained experimental and numerical results reveal that the bulging region forms transiently depending on the penetration depth of the weld, showing a tendency to transition from a slight bulging to a fully developed bulging region between penetration depths of 6 mm and 9 mm, respectively.
T2 - 13th International Seminar "Numerical Analysis of Weldability"
CY - Seggau, Austria
DA - 04.09.2022
KW - Laser beam welding
KW - Deep penetration
KW - Bulge formation
KW - Numerical modeling
PY - 2023
SN - 978-3-85125-968-1
SN - 978-3-85125-969-8
SN - 2410-0544
VL - 13
SP - 101
EP - 126
PB - Verlag der Technischen Universität Graz
AN - OPUS4-58802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Chunliang
A1 - Wu, Chuansong
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical analysis of ultrasonic vibration enhanced friction stir welding of dissimilar Al/Mg alloys
N2 - The ultrasonic vibration enhanced friction stir welding (UVeFSW) process has unique advantages in joining dissimilar Al/Mg alloys. While there are complex coupling mechanisms of multi-fields in the process, it is of great significance to model this process, to reveal the influence mechanism of ultrasonic vibration on the formation of Al/Mg joints.
In this study, the acoustic-plastic constitutive equation was established by considering the influence of both ultrasonic softening and residual hardening on the flow stress at different temperatures and strain rates. And the ultrasonic induced friction reduction (UiFR) effect on friction coefficient in different relative directions at the FSW tool-workpiece interface was quantitatively calculated and analyzed.
The Al/Mg UVeFSW process model was developed through introducing the above acoustic effects into the model of Al/Mg friction stir welding (FSW). The ultrasonic energy is stronger on the aluminum alloy side. In the stirred zone, there is the pattern distribution of ultrasonic sound pressure and energy. The heat generation at the tool-workpiece contact interface and viscous dissipation were reduced after applying ultrasonic vibra-tion. Due to the UiFR effect, the projection of friction coefficient and heat flux distributions at the tool-workpiece interface present a "deformed" butterfly shape. The calculated results show that ultrasonic vibra-tion enhanced the material flow and promoted the mixing of dissimilar materials.
T2 - 13th International Seminar Numerical Analysis of Weldability
CY - Seggau, Austria
DA - 04.09.2022
KW - Friction stir welding
KW - Ultrasonic vibration
KW - Al/Mg alloys
KW - Numerical simulation
PY - 2023
SN - 2410-0544
VL - 13
SP - 517
EP - 538
PB - Verlag der Technischen Universität Graz
AN - OPUS4-58805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, R.
A1 - Bähring, S.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Künstliche Neuronale Netze zur Qualitätsprognose von Funktional Gradierten Materialien im laserbasierten Directed Energy Deposition
N2 - Durch pulverbasiertes Directed-Energy Deposition lassen sich Gradierungen fertigen, um diskrete Materialübergänge zu vermeiden und die Lebensdauer von Hartschichten zu erhöhen. Die Kombination aus Stahl als Basiswerkstoff und einer verschleiß- und korrosionsbeständigen Co-Cr Legierung verspricht durch Vermeiden von Spannungskonzentrationen das Verhindern von Abplatzungen und Rissen in der Schutzschicht. Um die Qualität des gefertigten Bauteils zu beurteilen, liegen für solche Funktional Gradierten Materialien (FGM) wenig Erkenntnisse vor. Daher wird im Rahmen dieser Studie eine Methodik erarbeitet, um die relative Dichte eines Funktional Gradierten Materials auf Stahl und Co-Cr Basis mittels Maschinendaten zu bestimmen. Anschließend wird unter Einsatz eines künstlichen neuronalen Netzes anhand von Sensordaten die relative Dichte vorhergesagt. Das trainierte Netz erreicht eine Vorhersagegenauigkeiten von 99,83%. Abschließend wird eine Anwendung anhand von einem Demonstrator gezeigt.
T2 - 3. Fachtagung Additive Manufacturing
CY - Halle, Germany
DA - 05.10.2023
KW - Directed Enery Deposition
KW - Künstliche Neuronale Netze
KW - Additive Manufacturing
KW - DED
KW - KI
KW - AM
PY - 2023
SP - 1
EP - 8
PB - SLV Halle
AN - OPUS4-58692
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mente, Tobias
T1 - Schadensprävention durch Werkstoff- und Komponentenprüfung unter Druckwasserstoff
N2 - Historischer Schadensfall Wasserstoff-Gasflaschen von A. Martens aus dem Jahr 1894 / Kurzvorstellung H2Safety und ModuH2Pipe / Prüfung von Hohlzugproben unter Druckwasserstoff
T2 - 49. VDI-Jahrestagung Schadensanalyse - Schadensprävention bei Druckwasserstoff und Schadensprävention für Kunststoff- und Elastomerprodukte
CY - Würzburg, Germany
DA - 18.10.2023
KW - Hohlzugprobe
KW - Wasserstoff
KW - H2Safety@BAM
KW - MatCom
KW - ModuH2Pipe@BAM
PY - 2023
AN - OPUS4-58624
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Automated quantum-chemical bonding analysis with workflow tools
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale. The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials. Furthermore, other recent workflow contributions to the Materials Project software infrastructure (pymatgen, atomate2) related to phonons and machine-learning potentials will be discussed.
T2 - ADIS Workshop 2023
CY - Tegernsee, Germany
DA - 29.10.2023
KW - Automation
KW - Materials Properties
KW - DFT
KW - Workflows
KW - Machine Learning
KW - Thermodynamic Properties
PY - 2023
AN - OPUS4-58745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Prediction of the fatigue limit of additively manufactured metallic materials
N2 - Structural alloys are largely employed in key industrial sectors and their demand is predicted to rise rapidly for the next decades. Most of these materials require a large amount of energy for extraction and manufacturing, which causes the emission of greenhouse gases and other pollutants. Therefore, strategies for improving the sustainability of structural metallic alloys are urgently needed.
Additive Manufacturing (AM), in particular Laser Powder Bed Fusion (PBF-LB/M), aims to be a sustainable manufacturing process, as it allows the build-up of complex geometry in near net-shape from 3D models, while minimizing material waste and the energy required for the process and post-process treatments.
Nevertheless, the application of additively manufactured parts in structural safety-relevant applications is still hindered by the poor fatigue performance. The cause of this has been mainly attributed to the presence of manufacturing defects and surface roughness. Therefore, a huge effort has been made to optimize the process parameters and to introduce post-process treatments to minimize the defect content. However, material flaws cannot be fully eliminated, but these can be considered in a damage tolerance framework for the prediction of the fatigue performance of additively manufactured metallic materials, which is essential for part design and qualification.
This work aims at presenting different modelling strategies for the prediction of the fatigue limit of AM metals. Simple empirical models and more complex models based on fatigue short crack propagation are proposed. The investigated material is an AlSi10Mg alloy fabricated by PBF-LB/M and subjected to two different low-temperature heat-treatments (265°C for 1 h and 300°C for 2h). The results show that the models can provide good approximation of the fatigue limits and help in the interpretation of the scatter of fatigue data.
T2 - ASTM International Conference on Advanced Manufacturing
CY - Washington DC, USA
DA - 30.10.2023
KW - Additive Manufacturing
KW - AlSi10Mg
KW - Fatigue
KW - Residual stress
KW - Microstructure
PY - 2023
AN - OPUS4-58866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Fatigue assessment procedure based on effective crack propagation data and cyclic R-curve
N2 - Fracture mechanics-based methods can be applied to the fatigue assessment of mechanical components containing defects or cracks subjected to cyclic loading. The knowledge of the crack growth behavior for short and long cracks enables the determination of both finite and infinite life regimes. Nevertheless, a first problem arises from the empirical determination of the fatigue data, which vary according to the test conditions, e.g., the test method, frequency and the stress ratio R. This is due to crack closure and further environmental phenomena affecting crack propagation behavior. A second issue regards the lack of standard experimental procedures for the determination of the fatigue crack propagation threshold ΔKth dependency on the crack size. This is problematic, since ΔKth increases with the build-up of the closure effects in the short crack regime and its inaccurate experimental determination leads to large deviations in the assessment and, even more critical, to non-conservative predictions. Aiming at providing more reliable and safer assessment procedures, the present work proposes a method based on effective crack growth data obtained at high stress ratios (R ≈ 0.8). A short-crack model based on the cyclic R-curve and CPLR data is employed for describing the development of the closure effects. The predictions are compared to established methods and validated by experimental tests.
T2 - Fatigue 2022+1
CY - Hiroshima, Japan
DA - 06.11.2023
KW - Component assessment
KW - Fatigue crack propagation
KW - Fatigue threshold
KW - Crack closure
KW - Cyclic R-curve
PY - 2023
AN - OPUS4-58842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Putra, Stephen Nugraha
T1 - Einfluss der Temperaturabhängigen Modellierung der Laserstrahlabsorption auf die Schmelzbadgeometrie beim Hochleistungslaserstrahlschweißen
N2 - Der Absorptionsgrad metallischer Werkstoffe spielt bei Fügeprozessen mit einer Strahlungsquelle wie dem Hochleistungslaserstrahltiefschweißen eine bedeutende Rolle. Dieser beeinflusst die Menge der absorbierten Laserenergie, welche zum Aufschmelzen sowie zur lokalen Verdampfung des zu verbindenden Materials führt. Eine der wichtigsten Eigenschaften der Laserstrahlabsorption ist die Temperaturabhängigkeit. Dennoch wird sie in vielen Simulationsarbeiten häufig ignoriert und stattdessen ein angepasster Parameter zur Kalibrierung der Ergebnisse implementiert. Diese Vorgehensweise wirkt sich negativ auf die Zuverlässigkeit sowie die Genauigkeit des numerischen Modells sowie auf die Vorhersagbarkeit der Simulationsergebnisse aus. In der vorliegenden Arbeit wird die Temperaturabhängigkeit der Laserabsorption in ein selbstkonsistentes zweiphasiges Modell unter Berücksichtigung der gekoppelten 3D-Fluidströmung und Wärmeübertragung einbezogen. Die berechnete Laserstrahlabsorption wird durch die temperaturabhängigen Materialeigenschaften, die Lasercharakteristik und den Einfallswinkel des Laserstrahls bestimmt. Die freie Oberfläche jeder Phase wird mithilfe der volume-of-fluid Methode, kurz VOF, berechnet und die Laser-Material-Wechselwirkung wird durch ein neulich implementiertes Ray-Tracing-Verfahren modelliert, die auf einem lokalisierten Level-Set-Algorithmus basiert. Anschließend wird die transiente Wärmeeinbringung und die Geometrie der Schweißnaht analysiert und mit dem temperaturunabhängigen Absorptionsmodell verglichen. Es wurde festgestellt, dass die Temperaturabhängigkeit der Laserabsorption entscheidend für die genaue Bestimmung der Wärmeeinbringung und der Schmelzbadgeometrie ist. Das entwickelte Modell wurde anhand der experimentellen Untersuchungen validiert und die Bedeutung der Temperaturabhängigkeit bei der Laserstrahlabsorption wurde für die Simulation des Laserstrahltiefschweißens aufgeklärt.
T2 - 44. Assistentenseminar
CY - Päwesin, Germany
DA - 20.09.2023
KW - Laser beam welding
KW - Temperature dependent absorption
KW - Weld pool dynamics
KW - Numerical modeling
PY - 2023
AN - OPUS4-58810
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Putra, Stephen Nugraha
T1 - Der Einfluss verschiedener räumlicher Diskretisierungsansätze des Ray-Tracing-Verfahrens bei der Simulation des Laserstrahltiefschweißen
N2 - Die Wärmeverteilung des Lasers beim Laserstrahltiefschweißen ist für die Formgebung der Dampfkapillare und für die Schweißbaddynamik entscheidend. In dieser Arbeit werden die Laserwärmeverteilung und deren Einflüsse auf die Schweißbadtiefe sowie -breite numerisch anhand des Ray-Tracing-Verfahrens analysiert. Hierbei wird der La-serstrahl in mehreren Strahlenbündeln bzw. Subrays unterteilt. Diesbezüglich soll der Pfad der Subrays präzis berechnet werden, um die Dynamik der Dampfkapillare und des Schweißbades eines realen Schweißprozesses richtig abzubilden. Zu diesem Zweck beschäftigt sich die vorliegende Arbeit mit der Genauigkeitsverbesserung der Kontaktposition und der Reflexionsrichtung der Subrays auf der freien Oberfläche anhand der Level-Set-Methode. Um die Güte dieses Simulationsansatzes zu gewährleisten, wurde eine Gegenüberstellung mit den zwei klassi-schen Ray-Tracing-Verfahren mittels drei verschiedenen Benchmark-Testreihen durchgeführt. Anschließend wur-den die Versuchsergebnisse zur Validierung der implementierten numerischen Ansätze verwendet. Im Rahmen dieser Arbeit kann es gezeigt werden, dass unterschiedliche Wärmeverteilung aufgrund der verschiedenen Ray-Tracing-Verfahren deutlich zu erkennen ist, welche wiederum die Schweißbaddynamik sowie die lokalisierte Dampfkapillardynamik stark beeinflussen. Ferner wurde es bestätigt, dass die implementierte Level-Set-Methode zu einer genaueren Ermittlung der Kontaktposition und der Reflexionsrichtung der Subrays und somit zu einer Ver-besserung der simulierten Schmelzkontur führt.
T2 - 43. Assistentenseminar
CY - Schwarzenberg, Germany
DA - 27.09.2022
KW - Laser beam welding
KW - Ray tracing method
KW - Weld pool dynamics
KW - Numerical modeling
PY - 2022
AN - OPUS4-58840
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Determination of the Kitagawa-Takahashi diagram for the EA4T railway axle steel by means of the cyclic R-curve method
N2 - The Kitagawa-Takahashi (KT) diagram is a well-established tool in the fatigue community for the prediction of the fatigue limit of metallic materials in presence of defects. Nevertheless, its determination is associated with a large number of fatigue tests carried out on specimens with artificial defects (notches) to describe the fatigue limit-defect size relationship in the short crack regime. The preparation of the specimens and the execution of the tests is time expensive. Therefore, few phenomenological models have been introduced in the past to provide a first approximation of the KT diagram based solely on the fatigue limit for smooth specimen and the fatigue crack propagation threshold for long cracks. Despite the use of such models is widely spread, these suffer from problems related to the uncertainties of the material parameters. Furthermore, the mechanics of short cracks, which is the physical mechanism behind the concept of the fatigue limit, is not considered. This work discusses the advantages and drawbacks of using short fatigue crack propagation models for predicting the fatigue limit of flawed metallic materials. The KT diagrams for a EA4T railway axle steel in as-received and full-hardened condition are approximated by means of the cyclic R-curve method.
T2 - 13th International Fatigue Congress
CY - Hiroshima, Japan
DA - 06.11.2023
KW - Fatigue limit
KW - Crack propagation
KW - Short crack
KW - Cyclic R-curve
KW - EA4T railway axle steel
PY - 2023
AN - OPUS4-58867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy
N2 - ZIF-8 is a prominent member of the zeolitic imidazolate frameworks (ZIFs) subfamily of MOFs which possesses high thermal, chemical, and mechanical stabilities. Different routes have been explored to achieve the large-scale production of ZIF-8. However, these synthetic procedures are often inconsistent with the principles of sustainable chemical manufacturing. Aimed at developing scalable and greener production of ZIF-8, we adapted our previously reported in-batch „mix and wait“ synthesis[2] to continuous extrusion. To optimize the process, in-situ Raman spectroscopy was applied. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of MOF syntheses in view of their large-scale production.
The synthesis of ZIF-8 was performed using a twin-screw extruder ZE 12 HMI equipped with an automatic volumetric feeder ZD 12B (Three-Tec GmbH, Switzerland) and peristaltic pump BT-L (Lead Fluid, China). The process was monitored in six different zones using a Raman RXN1TM analyzer (Kaiser Optical Systems, France) with a non-contact probe head. PMMA screw-in parts, which are transparent to Raman laser radiation, were specially manufactured to provide the laser focus within the barrel. PXRD, TGA, N2 adsorption measurements, and SEM were used as complementary techniques to characterize the extrudates.
The batch ‘mix and wait’ synthesis of ZIF-8, consisting of bringing solid basic zinc carbonate and 2-methylimidazole in contact in a closed vial, was successfully adapted to reactive extrusion. The crystalline ZIF-8 continuously forms in the extruder under the mixing of solid reagents in the presence of a catalytic amounts of H2O or EtOH. The temperature, type of liquid, feeding rate, and excess of linker were optimized using in situ Raman spectroscopy. Pure and highly crystalline ZIF-8 was isolated at 40 °C by adding a catalytic amount of EtOH and a linker excess of 25%. The resulting material has excellent porosity with the BET surface area slightly exceeding that of the reference Basolite® Z1200 (1816 vs. 1734 m2 g–1). The reaction could yield ~ 3 kg d–1 assuming a continuous operation, with a space-time yield of ca. 67,000 kg m–3 d–1. The present method was compared to the published pathways based on Green Chemistry principles and proved to have the highest potential for large-scale production of ZIF-8.
T2 - 5th European Conference on Metal Organic Frameworks and Porous Polymers (EuroMOF2023)
CY - Granada, Spain
DA - 24.09.2023
KW - In situ Raman
KW - Reactive extrusion
KW - Green chemistry
KW - Mechanochemistry
KW - MOFs
KW - Large-scale synthesis
PY - 2023
AN - OPUS4-58950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
A1 - Schwab, Alexander
T1 - Reactive extrusion of a model BSA@ZIF-8 biocomposite: a scalable, continuous and sustainable approach
N2 - Metal-organic framework-based biocomposites (MOF-biocomposites) are promising materials for biosensing, biocatalysis, and delivery of biopharmaceuticals. One of the most studied MOFs for bioapplications is ZIF-8 (zeolitic imidazolate framework 8) due to its high surface area, high thermal and chemical stability, and low cytotoxicity. The conventional synthesis of ZIF-8-biocomposites called biomimetic mineralization includes mixing selected biomolecules 2-methylimidazole, and soluble Zn2+ source in water. Despite the high efficiency of the method, it does not allow for large-scale production and is restricted to hydrophilic biomolecules. Aimed at developing a scalable and versatile approach, we adapted our recently-reported ZIF-8 reactive extrusion for biocomposite production.
We selected bovine serum albumin (BSA) as an inexpensive model biomacromolecule for the preparation of biocomposites. The synthesis of BSA@ZIF-8 was performed using a twin-screw extruder ZE 12 HMI (Three-Tec Gmbh) at a mild temperature of 40 °C. Automatic volumetric feeder ZD 12B (Three-Tec GmbH) was used to supply the reagent mixture consisting of 2-methylimidazole, zinc source, and BSA. To initiate the reaction, a catalytic amount of EtOH was added using a peristaltic pump BT-L (Lead Fluid, China). Powder X-Ray diffraction (PXRD), thermogravimetric analysis (TGA), FTIR, and N2 adsorption were used to characterize the extrudates.
Highly crystalline and pure BSA@ZIF-8 with different BSA loadings was isolated after washing the extrudate with EtOH and sodium dodecyl sulfate. The EtOH feeding rate was optimized by following the protein encapsulation efficiency at a BSA mass fraction of 10%. A continuous extruder operation under optimized conditions showed good reproducibility and capability of producing biocomposites on the kilograms scale. These results provide highly valuable information for cheap and large-scale production of ZIF-8-based biocomposites. Due to the lack of restrictions on molecule size and solubility, our proof-of-concept study may significantly expand the selection of biomolecules for immobilization in ZIF-8, making the method applicable to various functional applications
T2 - Tag der Chemie 2023
CY - Berlin, Germany
DA - 05.07.2023
KW - Biocomposite
KW - MOFs
KW - Reactive extrusion
KW - Zeolitic imidazolate framework
PY - 2023
AN - OPUS4-58949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Putra, Stephen Nugraha
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Der Einfluss verschiedener räumlicher Diskretisierungsansätze des Ray-Tracing-Verfahrens bei der Simulation des Laserstrahltiefschweißen
N2 - Die Wärmeverteilung des Lasers beim Laserstrahltiefschweißen ist für die Formgebung der Dampfkapillare und für die Schweißbaddynamik entscheidend. In dieser Arbeit werden die Laserwärmeverteilung und deren Einflüsse auf die Schweißbadtiefe sowie -breite numerisch anhand des Ray-Tracing-Verfahrens analysiert. Hierbei wird der La-serstrahl in mehreren Strahlenbündeln bzw. Subrays unterteilt. Diesbezüglich soll der Pfad der Subrays präzis be-rechnet werden, um die Dynamik der Dampfkapillare und des Schweißbades eines realen Schweißprozesses rich-tig abzubilden. Zu diesem Zweck beschäftigt sich die vorliegende Arbeit mit der Genauigkeitsverbesserung der Kontaktposition und der Reflexionsrichtung der Subrays auf der freien Oberfläche anhand der Level-Set-Methode. Um die Güte dieses Simulationsansatzes zu gewährleisten, wurde eine Gegenüberstellung mit den zwei klassischen Ray-Tracing-Verfahren mittels drei verschiedenen Benchmark-Testreihen durchgeführt. Anschließend wurden die Versuchsergebnisse zur Validierung der implementierten numerischen Ansätze verwendet. Im Rahmen dieser Arbeit kann es gezeigt werden, dass unterschiedliche Wärmeverteilung aufgrund der verschiedenen Ray-Tracing-Verfahren deutlich zu erkennen ist, welche wiederum die Schweißbaddynamik sowie die lokalisierte Dampfkapil-lardynamik stark beeinflussen. Ferner wurde es bestätigt, dass die implementierte Level-Set-Methode zu einer ge-naueren Ermittlung der Kontaktposition und der Reflexionsrichtung der Subrays und somit zu einer Verbesserung der simulierten Schmelzkontur führt.
T2 - 43. Assistentenseminar Füge- und Schweißtechnik
CY - Schwarzenberg/Erzgebirge, Germany
DA - 27.09.2022
KW - Laser beam welding
KW - Ray tracing method
KW - Weld pool dynamics
KW - Numerical modeling
PY - 2023
UR - https://www.dvs-media.eu/de/neuerscheinungen/4584/43.-assistentenseminar-fuegetechnik
SN - 978-3-96144-212-6
VL - 386
SP - 91
EP - 102
PB - DVS Media GmbH
CY - Düsseldorf
AN - OPUS4-59119
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding with bonding analysis
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics for materials. More and more frequently, they are used as features in machine learning. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying these local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale and for machine-learning approaches. The latter relates to a general trend toward automation in density functional-based materials science. The lecture will demonstrate how our tools, that assess local atomic environments, helped to test and develop heuristics and design rules and an intuitive understanding of materials.
T2 - 2023 MRS Fall Meeting & Exhibit
CY - Boston, Massachusetts, USA
DA - 26.11.2023
KW - Automation
KW - Machine learning
KW - Materials Understanding
KW - Magnetism
KW - Phonons
PY - 2023
AN - OPUS4-59002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, R.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Laser-Pulver-Auftragschweißen von funktional gradierten Materialien auf Cobalt-Chrom Basis
N2 - Um Bauteile vor Verschleiß und Korrosion zu schützen werden Beschichtungen aus resistenteren Materialien aufgetragen. Hierzu zählen unter anderen die Legierungen auf Cobalt-Chrom Basis. Der diskrete Materialsprung ist jedoch unter thermischen und mechanischen Belastungen häufig Ursache für das Versagen der Beschichtung. In dieser Arbeit werden daher Materialgradierungen von verschiedenen Stahllegierungen zu einer Cobalt-Chrom Basislegierung untersucht. Die Ergebnissen werden dafür auch mit Resultaten zu vorangegangenen Untersuchungen verglichen. Kern der Arbeit bilden geätzte Schliffbilder der Materialpaarungen und Auswertungen mittels Farbeindringprüfung sowie die metallografische Bestimmung der Porosität. Ziel der Arbeit ist ein defektfreier Aufbau der funktional gradierten Materialpaarungen.
T2 - 43. Assistentenseminar Fügetechnik
CY - Päwesin, Germany
DA - 20.09.2023
KW - Directed Enery Deposition
KW - Funktionally Graded Material
KW - Additive Manufacturing
KW - DED
KW - FGM
KW - AM
PY - 2023
SN - 978-3-96144-212-6
SP - 1
EP - 6
PB - DVS Media GmbH
AN - OPUS4-59116
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Chemists have solutions and know how to get rid of them
N2 - Metal-organic framework-based biocomposites (MOF-biocomposites) are promising materials for biosensing, biocatalysis, and delivery of biopharmaceuticals. One of the most studied MOFs for bioapplications is ZIF-8 (zeolitic imidazolate framework 8) due to its high surface area, high thermal and chemical stability, and low cytotoxicity. The conventional synthesis of ZIF-8-biocomposites called biomimetic mineralization includes mixing selected biomolecules 2-methylimidazole, and soluble Zn2+ source in water.[3] Despite the high efficiency of the method, it does not allow for large-scale production and is restricted to hydrophilic biomolecules. Aimed at developing a scalable and versatile approach, we adapted our recently-reported ZIF-8 reactive extrusion for biocomposite production.
We selected bovine serum albumin (BSA) as an inexpensive model biomacromolecule for the preparation of biocomposites. The synthesis of BSA@ZIF-8 was performed using a twin-screw extruder ZE 12 HMI (Three-Tec Gmbh) at a mild temperature of 40 °C. Automatic volumetric feeder ZD 12B (Three-Tec GmbH) was used to supply the reagent mixture consisting of 2-methylimidazole, zinc source, and BSA. To initiate the reaction, a catalytic amount of EtOH was added using a peristaltic pump BT-L (Lead Fluid, China). Powder X-Ray diffraction (PXRD), thermogravimetric analysis (TGA), FTIR, and N2 adsorption were used to characterize the extrudates.
Highly crystalline and pure BSA@ZIF-8 with different BSA loadings was isolated after washing the extrudate with EtOH and sodium dodecyl sulfate. The EtOH feeding rate was optimized by following the protein encapsulation efficiency at a BSA mass fraction of 10%. A continuous extruder operation under optimized conditions showed good reproducibility and capability of producing biocomposites on the kilograms scale. These results provide highly valuable information for cheap and large-scale production of ZIF-8-based biocomposites. Due to the lack of restrictions on molecule size and solubility, our proof-of-concept study may significantly expand the selection of biomolecules for immobilization in ZIF-8, making the method applicable to various functional applications
T2 - SALSA Make and Measure conference
CY - Berlin, Germany
DA - 13.09.2023
KW - In situ Raman
KW - Large-scale processing
KW - Reactive extrusion
KW - Large-scale production
KW - Mechanochemistry
PY - 2023
AN - OPUS4-58953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Artinov, Antoni
T1 - A General Analytical Solution for Two-Dimensional Columnar Crystal Growth during Laser Beam Welding of Thin Steel Sheets
N2 - The main solidification parameters, namely the crystal axis, the growth rate, and the cross-sectional area of the columnar crystal control the primary microstructure and thus the final weld seam properties.
Limited understanding of solidification parameters due to complexities in experimental and theoretical weld pool boundary determination and
its mathematical description.
Application of local Lamé curves for efficient weld pool boundary reconstruction Derivation of general analytical solutions for the main solidification parameters of a two-dimensional columnar crystal growth during laser beam welding of thin steel sheets.
The Lamé curves approximation technique was successfully applied for the reconstruction of the rear part of the two-dimensional steady-state weld pool boundary. General analytical expressions for the main solidification parameters, namely the crystal axis, the growth rate and the cross-sectional area of the crystal were derived.
The derived expressions and herewith obtained results were verified and validated by comparing them to known theoretical solutions and experimental measurements. Dimensionless analysis of the influence of the size and shape of the rear weld pool boundary on the solidification parameters was provided.
The derived general solutions and the analysis provided allow for critical welding parameters to be estimated and adapted accordingly to improve the welding process.
T2 - 3rd International Conference on Advanced Joining Processes
CY - Braga, Portugal
DA - 19.10.2023
KW - Laser beam welding
KW - Analytical solution
KW - Columnar crystal growth
PY - 2023
AN - OPUS4-59174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gugin, Nikita
T1 - Mixing Reactions Enable Green Synthesis of ZIF-8 at Large Scale: Batch and Continuous Modes
N2 - We report the scale-up of a batch solid synthesis of zeolitic imidazolate framework-8 (ZIF-8) for reactive extrusion. The crystalline product forms in the extruder directly under the mixture of solid 2-methylimidazole and basic zinc carbonate in the presence of a catalytic amount of liquid. The process parameters such as temperature, liquid type, feeding rate, and linker excess were optimized using the setup specifically designed for in situ Raman spectroscopy. Highly crystalline ZIF-8 with a Brunauer–Emmett–Teller (BET) surface area of 1816 m2 g–1 was quantitatively prepared at mild temperature using a catalytic amount of ethanol and a small excess of the linker. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of metal–organic framework (MOF) syntheses in view of their large-scale production.
T2 - 2023 #RSCPoster Twitter Conference
CY - Online meeting
DA - 28.02.2023
KW - MOFs
KW - Green chemistry
KW - Reactive extrusion
KW - Large-scale production
KW - Mechanochemistry
KW - Zeolitic imidazolate framework
PY - 2023
UR - https://twitter.com/NikitaGugin/status/1630538555675099139
AN - OPUS4-58951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - A fundamental study of physical mechanisms of wineglass-shaped fusion zone profile in laser melting
N2 - The fusion zone geometry in laser melting processes e.g., laser welding and laser-based additive manufacturing, of metallic materials has commonly a wineglass-shaped profile which is critical to the grain orientation and stress distribution. Hereby, we adopt for the first time a decoupling work through a combination of multi-physics modelling and experiments to reveal the fundamental mechanisms of this special morphology. Two physicsbased easy-to-use metal vapour models are proposed to consider the vapour’s momentum and thermal effects separately. It is found that the direct laser energy absorption and Marangoni shear stress which are widely hypothesised to dominate the wineglass-shape formation show only a minor influence. The additional heating from the metallic vapour plume rather than its momentum impact contributes predominantly to the enlarging of the molten pool top region, resulting directly in the formation of the wineglass-shaped fusion zone. The generality of the plume heating effect is also validated in two types of materials (steel and Al) in a wide range of parameters.
KW - Laser melting
KW - Fusion zone profile
KW - Wineglass shape
KW - Multi-physical modelling
KW - Metallic vapour plume
KW - Steel and Al
PY - 2024
DO - https://doi.org/10.1016/j.jmatprotec.2023.118265
SN - 0924-0136
VL - 324
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-59692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Karkhin, Victor
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Simulation of solidification during keyhole laser welding of thick plates
T1 - Моделирование процесса кристаллизациипри лазерной сварке со сквозным
проплавлением пластин большой толщины
N2 - A method of solving the thermo-fluid dynamics problem is presented, enabling the prediction of the shape and dimensions of the weld pool during keyhole laser welding of thick plates. It is shown that the rear weld pool boundary can be satisfactorily approximated by a set of superellipses (Lamé curves). The presence of a convex rear weld pool boundary in the mid-plane has been observed experimentally and reproduced numerically. It was shown that in this zone the concentration of liquating impurities increases and the local solidification temperature decreases, contributing to the susceptibility to hot cracking.
KW - Laser beam welding
KW - Three-dimensional crystallization
KW - Mathematical modeling
KW - Superellipse
KW - Thick steel plates
PY - 2024
DO - https://doi.org/10.34641/SP.2023.1062.5.041
VL - 5
SP - 31
EP - 36
AN - OPUS4-59639
LA - rus
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karkhin, Victor
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Simulation of solidification during laser welding of thin plates
T1 - Моделирование процесса кристаллизации при лазерной сварке пластин малой толщины
N2 - It is proposed to model the experimentally observed weld pool boundary with superellipses (Lamé curves) and to find the unknown parameters of the curves using optimization methods. It has been shown experimentally that during laser welding of austenitic stainless steel with a thickness of 2 mm at a speed of 20 mm/s, the rear weld pool part has a shape close to triangular which can be accurately approximated by a superellipse. Analytical dependences of the trajectory and growth rate of the crystal and its cross-sectional area on the geometry of the rear weld pool part are obtained.
KW - Laser beam welding
KW - Plane crystalization
KW - Mathematical modeling
KW - Superellipse
KW - Thin steel plates
PY - 2023
DO - https://doi.org/10.34641/SP.2023.1061.4.033
VL - 4
SP - 28
EP - 33
AN - OPUS4-59649
LA - rus
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-Driven Chemical Understanding with Bonding Analysis
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale. The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials. Furthermore, the general trend toward automation in density functional-based materials science and some of our recent contributions will be discussed.
T2 - Otaniemi Center for Atomic-scale Materials Modeling Seminar
CY - Aalto, Finland
DA - 11.03.2024
KW - Automation
KW - Materials Design
KW - Bonding Analysis
KW - Machine Learning
PY - 2024
AN - OPUS4-59671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - High-throughput and automated bonding Analysis
N2 - Talk as a part of the LOBSTER CECAM SCHOOL. This talk introduced all participants to automation tools around the software LOBSTER.
T2 - CECAM LOBSTER School
CY - Aalto, Finland
DA - 12.03.2024
KW - Automation
KW - Workflows
KW - Bonding Analysis
KW - Materials Design
KW - Chemically Complex Materials
PY - 2024
AN - OPUS4-59672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kruse, Julius
T1 - Anwendung der IBESS-Prozedur zur Berechnung der Schwingfestigkeit geschweißter bauteilähnlicher Proben mit künstlichen Defekten
N2 - Im Rahmen eines Kooperationsprojekts mit der Schottel GmbH wurde eine bauteilnahe Probengeometrie entwickelt, mit der sich unter Verwendung einer einachsigen Prüfmaschine das Spannungstiefenprofil in dem unter überlagerter Biege- und Zugspannung beanspruchtem Querschnitt im Schweißnahtübergang des Bauteils reproduzieren ließ.
Proben dieser Geometrie wurden vom Kooperationspartner im geschweißten bzw. geschweißten und spannungsarmgeglühten Zustand bereitgestellt. An der BAM wurden je Wärmebehandlungszustand mittels Senkerodieren zwei verschiedene künstliche Defektgeometrien im Schweißnahtübergang eingebracht.
Anhand der Proben wurden experimentell für alle vier Probenzustände Wöhlerlinien für ein Spannungsverhältnis von R = 0,1 ermittelt.
Zusätzlich wurde das u.a. an der BAM entwickelte IBESS-Verfahren angewandt, um die Wöhlerlinien analytisch zu bestimmen. Hierbei wurde eine sehr gute Übereinstimmung von Berechnung und Experiment erreicht, wobei die Berechnung zu einer leicht konservativen Lebensdauervorhersage führte.
T2 - 56. DVM Tagung "Bruchmechanik und Bauteilsicherheit"
CY - Kassel, Germany
DA - 20.02.2024
KW - Bruchmechanik
KW - Ermüdung
KW - Schwingfestigkeit
KW - Schweißverbindungen
PY - 2024
AN - OPUS4-59781
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Data-driven chemical understanding with bonding analysis
N2 - Bonds and local atomic environments are crucial descriptors of material properties. They have been used to create design rules and heuristics and as features in machine learning of materials properties. Implementations and algorithms (e.g., ChemEnv and LobsterEnv) for identifying local atomic environments based on geometrical characteristics and quantum-chemical bonding analysis are nowadays available. Fully automatic workflows and analysis tools have been developed to use quantum-chemical bonding analysis on a large scale. The lecture will demonstrate how our tools, that assess local atomic environments and perform automatic bonding analysis, help to develop new machine learning models and a new intuitive understanding of materials.[5,6] Furthermore, the general trend toward automation in density functional-based materials science and some of our recent contributions will be discussed.
T2 - Seminar of the Department of Chemistry at Imperial College London
CY - Online meeting
DA - 20.02.2024
KW - Automation
KW - Magnetism
KW - Bonding Analysis
KW - Machine Learning
PY - 2024
AN - OPUS4-59546
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
T1 - Ontology-Oriented Modeling of the Vickers Hardness Knowledge Graph
N2 - This research deals with the development of the Vickers hardness knowledge graph, mapping the example dataset in them, and exporting the data-mapped knowledge graph as a machine-readable Resource Description Framework (RDF). Modeling the knowledge graph according to the standardized test procedure and using the appropriate upper-level ontologies were taken into consideration to develop the highly standardized, incorporable, and industrial applicable models. Furthermore, the Ontopanel approach was utilized for mapping the real experimental data in the developed knowledge graphs and the resulting RDF files were successfully evaluated through the SPARQL queries.
KW - Data Mapping
KW - FAIR Data
KW - Ontology
KW - Knowledge Graph
KW - Vickers Hardness
PY - 2024
DO - https://doi.org/10.4028/p-k8Gj2L
VL - 149
SP - 33
EP - 38
PB - Trans Tech Publications Ltd
CY - Switzerland
AN - OPUS4-59981
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - New Opportunities for Data-Driven Chemistry and Materials Science Through Automation
N2 - In recent years, many protocols in computational materials science have been automated and made available within software packages (primarily Python-based). This ranges from the automation of simple heuristics (oxidation states, coordination environments) to the automation of protocols, including multiple DFT and post-processing tools such as (an)harmonic phonon computations or bonding analysis. Such developments also shorten the time frames of projects after such developments have been made available and open new possibilities. For example, we can now easily make data-driven tests of well-known rules and heuristics or develop quantum chemistry-based materials descriptors for machine learning approaches. These tests and descriptors can have applications related to magnetic ground state predictions of materials relevant for spintronic applications or for predicting thermal properties relevant for thermal management in electronics. Combining high-throughput ab initio computations with fitting, fine-tuning machine learning models and predictions of such models within complex workflows is also possible and promises further acceleration in the field. In this talk, I will show our latest efforts to link automation with data-driven chemistry and materials science.
T2 - MRS Spring
CY - Seattle, Washington, USA
DA - 21.04.2024
KW - Automation
KW - Workflows
KW - Chemical Bonding
KW - Thermal Properties
KW - Materials Design
PY - 2024
AN - OPUS4-59982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Analytische Prozedur zur Berechnung der Ermüdungslebensdauer basierend auf effektiven Rissfortschrittsdaten und zyklischer R-Kurve
N2 - Bruchmechanik-basierende Methoden können für die Ermüdungsbewertung von mechanischen Bauteilen angewendet werden, die Defekte oder Risse enthalten und zyklischen Belastungen ausgesetzt sind. Die Kenntnis des Risswachstumsverhaltens für kurze und lange Risse ermöglicht die Bestimmung sowohl endlicher als auch unendlicher Lebensdauer. Ein erstes Problem ergibt sich jedoch aus der empirischen Bestimmung von Ermüdungswerkstoffkennwerten, die je nach Prüfbedingungen, z. B. Prüfmethode, Frequenz und Spannungsverhältnis R, variieren. Dies ist auf die Rissschließeffekte und weitere Umgebungsphänomene zurückzuführen, die das Rissfortschrittsverhalten beeinflussen. Ein zweites Problem ist das Fehlen von Standardversuchsverfahren zur Bestimmung des Schwellenwerts gegen Ermüdungsrissausbreitung ΔKth in Abhängigkeit von der Rissausbreitung. Dies ist problematisch, da ΔKth mit der Zunahme der Rissschließeffekte im Kurzrissbereich zunimmt und seine ungenaue experimentelle Bestimmung zu großen Abweichungen bei der Bewertung und, was noch kritischer ist, zu nicht konservativen Vorhersagen führt. Mit dem Ziel, zuverlässigere und sicherere Bewertungsverfahren bereitzustellen, wird in dieser Arbeit eine Methode vorgeschlagen, die auf effektiven Risswachstumsdaten basiert, die bei hohen Spannungsverhältnissen (R ≈ 0,8) ermittelt wurden. Zur Beschreibung der Entwicklung der Rissschließeffekte wird ein Kurzrissmodell auf der Grundlage von zyklischen R-Kurven und CPLR-Daten verwendet. Die analytischen Vorhersagen werden mit experimentellen Daten verglichen, die zur Validierung des Verfahrens durchgeführt wurden, und die daraus entstandenen Unterschiede werden diskutiert.
Übersetzt mit DeepL.com (kostenlose Version)
T2 - BMDK-Seminar SS24
CY - Magdeburg, Germany
DA - 10.04.2024
KW - Schwellenwert gegen Ermüdungsrissausbreitung
KW - Rissschließeffekte
KW - Ermüdungslebensdauer
KW - Zyklische R-Kurve
PY - 2024
AN - OPUS4-59876
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beygi Nasrabadi, Hossein
T1 - Digital representation of materials testing data for semantic web analytics: Tensile stress relaxation testing use case
N2 - This study aims to represent an approach for transferring the materials testing datasets to the digital schema that meets the prerequisites of the semantic web. As a use case, the tensile stress relaxation testing method was evaluated and the testing datasets for several copper alloys were prepared. The tensile stress relaxation testing ontology (TSRTO) was modeled following the test standard requirements and by utilizing the appropriate upper-level ontologies. Eventually, mapping the testing datasets into the knowledge graph and converting the data-mapped graphs to the machine-readable Resource Description Framework (RDF) schema led to the preparation of the digital version of testing data which can be efficiently queried on the web.
T2 - ICMDA 2024: 7th International Conference on Materials Design and Applications
CY - Tokyo, Japan
DA - 09.04.2024
KW - Digitalization
KW - Tensile stress relaxation
KW - Ontology
KW - Mechanical testing
KW - Semantic web
PY - 2024
AN - OPUS4-59979
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bhadeliya, Ashok
T1 - High temperature fatigue crack growth in nickel-based alloys joined by brazing and additive manufacturing
N2 - Gas turbine components, made of nickel-based alloys, undergo material damage due to high temperatures and mechanical stresses. These components need periodic replacement to avoid efficiency loss and failure. Repair of these parts is more cost-effective than replacement. State-of-the-art repair technologies, including different additive manufacturing (AM) and brazing processes, are considered for efficient restoration. Materials properties mismatches and/or internal defects in repaired parts may expedite crack initiation and propagation, reducing fatigue life. To understand the crack growth behavior in joining zones and predict the remaining life of repaired components, fatigue crack growth (FCG) tests were conducted on specimens of nickel-based alloys joined via brazing, pre-sintered preforms and AM. The FCG experimental technique was successfully adapted for joined specimens and results indicate that the investigated braze material provides a lower resistance to crack growth. In AM-sandwich specimens, the crack growth rates are significantly reduced at the interface of AM and cast material.
T2 - TMS 2024 Annual Meeting & Exhibition
CY - Orlando, Florida, USA
DA - 03.03.2024
KW - Fatigue crack growth
KW - Joined nickel-based alloys
PY - 2024
AN - OPUS4-59854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaudhuri, Somsubhro
T1 - Thermography-Assisted Mechanical Testing of Cold-Spray (AM) Repair
N2 - Cold Spray Additive Manufacturing (CSAM) is a solid-state process that is being increasingly used for structural repairs in aerospace and energy sectors. It enables the deposition of dense material at low temperatures by accelerating metal particles to supersonic velocities, thereby reducing thermal distortion. However, the structural integrity of CSAM repairs—particularly at the interface between the deposited layer and the substrate—remains a critical concern. Various post-treatments and characterization methods have been explored to optimize performance. While X-ray Computed Tomography (XCT) is effective for sub-surface inspection, it cannot be applied in situ during mechanical testing. Digital Image Correlation (DIC), a surface-based method, also lacks sub-surface sensitivity. To address this, Infrared Thermography (IRT) was employed alongside DIC during the tensile and fatigue testing of aluminum CSAM-repaired specimens. A cooled IRT camera operating at 200 FPS captured thermal data, with lock-in processing subsequently applied in post-processing. IRT successfully detected early interfacial damage and enabled the tracking of crack propagation, which was later confirmed through fracture surface analysis.
T2 - Advanced Infrared Technology and Applications (AITA) 2025
CY - Kobe, Japan
DA - 15.09.2025
KW - Thermography
KW - Thermografie
KW - Thermal stress analysis
KW - Cold spray
KW - Damage detection
PY - 2025
AN - OPUS4-64227
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gumenyuk, Andrey
T1 - Reducing Noise Impact on Strain Accuracy Measurement by Optical Flow and DIC for Laser Welding Applications
N2 - In recent years, non-contact methods for in situ local strain measurement during welding processes have gained increasing importance. This trend is driven by advancements in both measurement technology—such as improved camera systems, illumination sources, and X-ray techniques—and in image processing algorithms for strain evaluation. Laser beam welding poses specific challenges for optical strain measurement due to various types of process-related emissions that impair measurement accuracy. In this study, two different algorithms were applied to analyze the local strain field in the solidification zone during laser welding of AISI 310S stainless steel: the inverse compositional Gauss-Newton algorithm for Digital Image Correlation (DIC) and the Lucas-Kanade method for optical flow analysis [1]. Video sequences were recorded under Controlled Tensile Weldability Test (CTW) conditions, in which the specimens were subjected to a defined external tensile load during welding. This setup consistently induced solidification cracking at the material surface, which could be observed in the video recordings.
To enhance the robustness and accuracy of the strain evaluation, various noise reduction techniques were implemented. These included identification and mitigation of erroneous frames caused by process emissions and dynamic disturbances. The resulting strain distributions showed high repeatability across multiple experiments and were in good qualitative agreement with predictions from high-fidelity finite element simulations. [2].
T2 - AJP 2025
CY - Coimbra, Portugal
DA - 16.10.2025
KW - Laser beam welding
KW - Solidification cracking
KW - Optical measurement
PY - 2025
AN - OPUS4-64428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schilling, Markus
T1 - Semantic Technologies in Action: Integrating Mechanical and Microstructure Data in MSE
N2 - Semantic technologies (ST) are a powerful tool for storing, processing, and querying data in a contextualized and interoperable manner. They enable machine-actionable and human-readable knowledge representations essential for advanced data management, retrieval, and reuse. As one of the key factors within the frame of the collaborative project platform MaterialDigital (PMD), the establishment of a virtual material data space and the semantic modeling of hierarchical, process-dependent material data is aimed at to serve as best-practice examples of knowledge representation through ontologies and knowledge graphs.
In this presentation, the application of ST to a specific use case from the field of materials sciences and engineering (MSE) is demonstrated: the integration and analysis of data related to a 2000 series age-hardenable aluminum alloy. By semantically representing mechanical and microstructural data obtained from tensile tests and dark-field transmission electron microscopy across various aging times, an expandable knowledge graph was constructed that is aligned with the PMD Core Ontology (PMDco) and enriched through the Tensile Test (TTO) and Precipitate Geometry Ontologies. This semantically integrated dataset enables advanced analytical capabilities via SPARQL queries and reveals microstructure–property relationships consistent with the well-known Orowan mechanism. The approach highlights the potential of semantic data integration to support FAIR data principles and to foster a more data-centric and interoperable research infrastructure in MSE.
T2 - MSE Research Data Forum 2025
CY - Siegburg, Germany
DA - 08.07.2025
KW - Semantic Data
KW - Data Integration
KW - Digitalization
KW - Data Interoperability
PY - 2025
AN - OPUS4-63666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
T1 - Application of the cyclic R-curve analysis to determine the Kitagawa-Takahashi Diagram
N2 - The fatigue limit of metallic materials corresponds to the maximum stress below which all microcracks that were originally able to grow still arrest. In technical alloys, microcracks are normally initiated at material defects. As a result, the fatigue limit of these materials is a function of the defect size. The Kitagawa-Takahashi Diagram (KT-diagram) provides a useful description of this dependency. However, the established methods for its determination are associated with great uncertainties, especially in the technically interesting region corresponding to the short crack regime. In addition, the effect of crack closure and the influence of local stresses are not considered. For this reason, short crack models offer a better alternative for estimating KT-diagrams. In this work, a methodology is presented that incorporates the determination of the fatigue limit based on crack arrest (cyclic R-curve analysis). The crack driving force is determined by FE simulations, while the increase in material resistance with cyclic crack propagation in the region of physically short cracks is described experimentally by the cyclic R-curve. To validate the procedure, fatigue limit tests based on the staircase method are carried out on smooth and notched specimens with 3 different notch sizes. Furthermore, tests are carried out on a low-alloyed steel with two different heat treatments for considering different strengths. The experimental results are compared with the simulations and the possible differences are discussed.
T2 - 5th International Symposium on Fatigue Design and Material Defects
CY - Trento, Italy
DA - 14.05.2025
KW - Fatigue limit
KW - Material defects
KW - Kitagawa-Takahashi Diagram
KW - Cyclic R-curve analysis
PY - 2025
AN - OPUS4-63144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Madia, Mauro
T1 - Influence of defects on the fatigue strength of parts repaired by cold spray
N2 - Cold spray repair is a promising and cost-saving alternative to replacing worn parts. Depositing of materials into machined damage volumes in decent quality can restore the performance of refurbished parts and extend their working life. Furthermore, repair counts as resource-efficient and green process in a world targeting at decarbonization of many industrial sectors. Despite the advantages, cold spray repair still suffers from major limitations which prevent its application in safety relevant parts. The main factors influencing the structural integrity concern the adhesion strength, inherent non-bonded internal interfaces, the reduced ductility by work hardening during the manufacturing process, and the presence of residual stresses. This work presents the results of the collaborative project CORE devoted to the development of automatized repair of aerospace parts by cold spray. The investigations considered the aluminum alloy Al6061-T6 which combines medium-high strength, good workability, and high corrosion resistance. Quasi-static tensile tests, high cycle fatigue and fatigue crack propagation tests were performed to compare the performance of base and repaired materials. These were complemented by fractographic and microstructural investigations.
T2 - 5th International Symposium on Fatigue Design and Material Defects
CY - Trento, Italy
DA - 14.05.2025
KW - Cold Spray
KW - Component Repair
KW - Fatigue Strength
KW - Defects
KW - Surface Treatment
PY - 2025
AN - OPUS4-63146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Durlo Tambara, Luís Urbano
T1 - Early hydration reactions of calcium sulfoaluminate cement in water and alkaline media
N2 - This study investigates the early hydration of calcium sulfoaluminate (CSA) cement in water (CSAH) and 2M NaOH (CSA2M), both with a liquid/solid ratio of 0.5. Hydration kinetics were assessed using in situ X-ray diffraction, isothermal conduction calorimetry, ultrasonic pulse velocity (UPV) and mechanical strength measurements. The results indicate that in the CSA2M system, the maximum heat release occurs earlier, and UPV measurements reveal a more rapid increase in mechanical stiffness (Figure 1a). The presence of alkalis accelerates the dissolution of ye’elimite and anhydrite, leading to a shorter induction period and faster precipitation of ettringite (Figure 1b-d). The phase refinement confirmed a higher dissolution rate of anhydrite in the alkaline environment, while the formation of ettringite stabilizes within 10 hours. Initial dissolution (0–40 min) increases ion concentration, followed by accelerated ettringite formation (0.6–2.5 h) with rising heat flow and UPV. A secondary acceleration (2.5–4.3 h) occurs only in CSAH. Deceleration (2.5–10 h) leads to further stabilization, with reactions proceeding at a slower rate. At 25 h, CSAH reached 58.3% ettringite and CSA2M 48.2%. These findings contribute to a deeper understanding of the early hydration mechanisms of CSA cement and the impact of alkalis on phase evolution.
T2 - 3rd International Workshop on Calcium Sulfoaluminate Cements
CY - Leeds, UK
DA - 23.06.2025
KW - Calcium sulfoaluminate cement
KW - Ultrasonic pulse velocity
KW - Early hydration
KW - Alkali
KW - In situ XRD
PY - 2025
AN - OPUS4-63758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanna, Naveen
A1 - Bär, Jürgen
A1 - Duarte, Larissa
A1 - Madia, Mauro
ED - Ricoeur, Andreas
T1 - Ermittlung von Kitagawa-Takahashi-Diagrammen mittels Gleichstrompotentialsondenmessungen
N2 - Das Kitagawa-Takahashi Diagramm ist ein wichtiges Werkzeug zur Beschreibung der ausgeprägten Langzeitfestigkeit fehlerbehafteter Bauteile. Insbesondere im technisch relevanten Übergangsbereich unterscheiden sich jedoch die verwendeten Modelle. Daher ist für eine sichere Aussage eine experimentelle Absicherung in diesem Bereich zwingend notwendig. In dieser Arbeit wird eine Methode vorgestellt, die eine einfache und schnelle Absicherung des Verlaufs im Übergangsbereich erlaubt. Hierzu werden in Flachproben mittels eines Gravierlasers scharfe Kerben mit einer definierten Breite und Tiefe eingebracht. Die so präparierten Proben werden mit blockweise steigender Last bis zum Bruch ermüdet. Die Erkennung von Anrissen erfolgt mittels einer Gleichstrom-Potentialsonde mit der auch die Länge des Lastblocks gesteuert wird.
T2 - 57. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Cologne, Germany
DA - 18.02.2025
KW - Ausgeprägte Langzeitfestigkeit
KW - Materialdefekte
KW - KT-Diagramm
KW - Gleichstrom-Potentialsonde
PY - 2025
DO - https://doi.org/10.48447/BR-2025-513
VL - 257
SP - 105
EP - 112
PB - Deutscher Verband für Materialforschung und -prüfung e.V.
CY - Berlin, Deutschland
AN - OPUS4-62604
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Kanna, Naveen
A1 - Bär, Jürgen
ED - Ricoeur, Andreas
T1 - Anwendung der zyklischen R-Kurven-Analyse zur Abschätzung des Kitagawa-Takahashi-Diagramms
N2 - Die ausgeprägte Langzeitfestigkeit eines Werkstoffes entspricht der maximalen Spannung, unterhalb derer alle ursprünglich wachstumsfähigen Mikrorisse arretieren. Für fehlerbehaftete Werkstoffe stellt das Kitagawa-Takahashi (KT)-Diagramm die Abhängigkeit der ausgeprägten Langzeitfestigkeit von der Defektgröße dar. Das KT-Diagramm kann mit großem Aufwand experimentell bestimmt oder durch verschiedene Modelle abgeschätzt werden. Solche Ansätze ergeben oft nichtkonservative Prognosen und berücksichtigen weder den Aufbau der Rissschließeffekte noch lokale Spannungen. In dieser Arbeit wird ein Kurzrissmodell auf Grundlage der zyklischen R-Kurve und des Rissarrestphänomens zur Abschätzung des KT-Diagramms vorgestellt. Die Abschätzungen werden mit experimentellen Daten validiert, die mit gekerbten Proben nach dem Treppenstufenverfahren ermittelt wurden.
T2 - 57. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit
CY - Köln, Germany
DA - 18.02.2025
KW - Langzeitfestigkeit
KW - KT-Diagramm
KW - zyklische R-Kurven-Analyse
PY - 2025
DO - https://doi.org/10.48447/BR-2025-512
VL - 257
SP - 93
EP - 104
PB - Deutscher Verband für Materialforschung und -prüfung e.V.
CY - Berlin, Deutschland
AN - OPUS4-62603
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -